1 /*
2 * Copyright (c) 2003, 2012, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/symbolTable.hpp"
27 #include "classfile/systemDictionary.hpp"
28 #include "classfile/vmSymbols.hpp"
29 #include "jvmtifiles/jvmtiEnv.hpp"
30 #include "oops/instanceMirrorKlass.hpp"
31 #include "oops/objArrayKlass.hpp"
32 #include "oops/oop.inline2.hpp"
33 #include "prims/jvmtiEventController.hpp"
34 #include "prims/jvmtiEventController.inline.hpp"
35 #include "prims/jvmtiExport.hpp"
36 #include "prims/jvmtiImpl.hpp"
37 #include "prims/jvmtiTagMap.hpp"
38 #include "runtime/biasedLocking.hpp"
39 #include "runtime/javaCalls.hpp"
40 #include "runtime/jniHandles.hpp"
41 #include "runtime/mutex.hpp"
42 #include "runtime/mutexLocker.hpp"
43 #include "runtime/reflectionUtils.hpp"
44 #include "runtime/vframe.hpp"
45 #include "runtime/vmThread.hpp"
46 #include "runtime/vm_operations.hpp"
47 #include "services/serviceUtil.hpp"
48 #ifndef SERIALGC
49 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"
50 #endif
51
52 // JvmtiTagHashmapEntry
53 //
54 // Each entry encapsulates a reference to the tagged object
55 // and the tag value. In addition an entry includes a next pointer which
56 // is used to chain entries together.
57
58 class JvmtiTagHashmapEntry : public CHeapObj<mtInternal> {
59 private:
60 friend class JvmtiTagMap;
61
62 oop _object; // tagged object
63 jlong _tag; // the tag
64 JvmtiTagHashmapEntry* _next; // next on the list
65
66 inline void init(oop object, jlong tag) {
67 _object = object;
68 _tag = tag;
69 _next = NULL;
70 }
71
72 // constructor
73 JvmtiTagHashmapEntry(oop object, jlong tag) { init(object, tag); }
74
75 public:
76
77 // accessor methods
78 inline oop object() const { return _object; }
79 inline oop* object_addr() { return &_object; }
80 inline jlong tag() const { return _tag; }
81
82 inline void set_tag(jlong tag) {
83 assert(tag != 0, "can't be zero");
84 _tag = tag;
85 }
86
87 inline JvmtiTagHashmapEntry* next() const { return _next; }
88 inline void set_next(JvmtiTagHashmapEntry* next) { _next = next; }
89 };
90
91
92 // JvmtiTagHashmap
93 //
94 // A hashmap is essentially a table of pointers to entries. Entries
95 // are hashed to a location, or position in the table, and then
96 // chained from that location. The "key" for hashing is address of
97 // the object, or oop. The "value" is the tag value.
98 //
99 // A hashmap maintains a count of the number entries in the hashmap
100 // and resizes if the number of entries exceeds a given threshold.
101 // The threshold is specified as a percentage of the size - for
102 // example a threshold of 0.75 will trigger the hashmap to resize
103 // if the number of entries is >75% of table size.
104 //
105 // A hashmap provides functions for adding, removing, and finding
106 // entries. It also provides a function to iterate over all entries
107 // in the hashmap.
108
109 class JvmtiTagHashmap : public CHeapObj<mtInternal> {
110 private:
111 friend class JvmtiTagMap;
112
113 enum {
114 small_trace_threshold = 10000, // threshold for tracing
115 medium_trace_threshold = 100000,
116 large_trace_threshold = 1000000,
117 initial_trace_threshold = small_trace_threshold
118 };
119
120 static int _sizes[]; // array of possible hashmap sizes
121 int _size; // actual size of the table
122 int _size_index; // index into size table
123
124 int _entry_count; // number of entries in the hashmap
125
126 float _load_factor; // load factor as a % of the size
127 int _resize_threshold; // computed threshold to trigger resizing.
128 bool _resizing_enabled; // indicates if hashmap can resize
129
130 int _trace_threshold; // threshold for trace messages
131
132 JvmtiTagHashmapEntry** _table; // the table of entries.
133
134 // private accessors
135 int resize_threshold() const { return _resize_threshold; }
136 int trace_threshold() const { return _trace_threshold; }
137
138 // initialize the hashmap
139 void init(int size_index=0, float load_factor=4.0f) {
140 int initial_size = _sizes[size_index];
141 _size_index = size_index;
142 _size = initial_size;
143 _entry_count = 0;
144 if (TraceJVMTIObjectTagging) {
145 _trace_threshold = initial_trace_threshold;
146 } else {
147 _trace_threshold = -1;
148 }
149 _load_factor = load_factor;
150 _resize_threshold = (int)(_load_factor * _size);
151 _resizing_enabled = true;
152 size_t s = initial_size * sizeof(JvmtiTagHashmapEntry*);
153 _table = (JvmtiTagHashmapEntry**)os::malloc(s, mtInternal);
154 if (_table == NULL) {
155 vm_exit_out_of_memory(s, "unable to allocate initial hashtable for jvmti object tags");
156 }
157 for (int i=0; i<initial_size; i++) {
158 _table[i] = NULL;
159 }
160 }
161
162 // hash a given key (oop) with the specified size
163 static unsigned int hash(oop key, int size) {
164 // shift right to get better distribution (as these bits will be zero
165 // with aligned addresses)
166 unsigned int addr = (unsigned int)((intptr_t)key);
167 #ifdef _LP64
168 return (addr >> 3) % size;
169 #else
170 return (addr >> 2) % size;
171 #endif
172 }
173
174 // hash a given key (oop)
175 unsigned int hash(oop key) {
176 return hash(key, _size);
177 }
178
179 // resize the hashmap - allocates a large table and re-hashes
180 // all entries into the new table.
181 void resize() {
182 int new_size_index = _size_index+1;
183 int new_size = _sizes[new_size_index];
184 if (new_size < 0) {
185 // hashmap already at maximum capacity
186 return;
187 }
188
189 // allocate new table
190 size_t s = new_size * sizeof(JvmtiTagHashmapEntry*);
191 JvmtiTagHashmapEntry** new_table = (JvmtiTagHashmapEntry**)os::malloc(s, mtInternal);
192 if (new_table == NULL) {
193 warning("unable to allocate larger hashtable for jvmti object tags");
194 set_resizing_enabled(false);
195 return;
196 }
197
198 // initialize new table
199 int i;
200 for (i=0; i<new_size; i++) {
201 new_table[i] = NULL;
202 }
203
204 // rehash all entries into the new table
205 for (i=0; i<_size; i++) {
206 JvmtiTagHashmapEntry* entry = _table[i];
207 while (entry != NULL) {
208 JvmtiTagHashmapEntry* next = entry->next();
209 oop key = entry->object();
210 assert(key != NULL, "jni weak reference cleared!!");
211 unsigned int h = hash(key, new_size);
212 JvmtiTagHashmapEntry* anchor = new_table[h];
213 if (anchor == NULL) {
214 new_table[h] = entry;
215 entry->set_next(NULL);
216 } else {
217 entry->set_next(anchor);
218 new_table[h] = entry;
219 }
220 entry = next;
221 }
222 }
223
224 // free old table and update settings.
225 os::free((void*)_table);
226 _table = new_table;
227 _size_index = new_size_index;
228 _size = new_size;
229
230 // compute new resize threshold
231 _resize_threshold = (int)(_load_factor * _size);
232 }
233
234
235 // internal remove function - remove an entry at a given position in the
236 // table.
237 inline void remove(JvmtiTagHashmapEntry* prev, int pos, JvmtiTagHashmapEntry* entry) {
238 assert(pos >= 0 && pos < _size, "out of range");
239 if (prev == NULL) {
240 _table[pos] = entry->next();
241 } else {
242 prev->set_next(entry->next());
243 }
244 assert(_entry_count > 0, "checking");
245 _entry_count--;
246 }
247
248 // resizing switch
249 bool is_resizing_enabled() const { return _resizing_enabled; }
250 void set_resizing_enabled(bool enable) { _resizing_enabled = enable; }
251
252 // debugging
253 void print_memory_usage();
254 void compute_next_trace_threshold();
255
256 public:
257
258 // create a JvmtiTagHashmap of a preferred size and optionally a load factor.
259 // The preferred size is rounded down to an actual size.
260 JvmtiTagHashmap(int size, float load_factor=0.0f) {
261 int i=0;
262 while (_sizes[i] < size) {
263 if (_sizes[i] < 0) {
264 assert(i > 0, "sanity check");
265 i--;
266 break;
267 }
268 i++;
269 }
270
271 // if a load factor is specified then use it, otherwise use default
272 if (load_factor > 0.01f) {
273 init(i, load_factor);
274 } else {
275 init(i);
276 }
277 }
278
279 // create a JvmtiTagHashmap with default settings
280 JvmtiTagHashmap() {
281 init();
282 }
283
284 // release table when JvmtiTagHashmap destroyed
285 ~JvmtiTagHashmap() {
286 if (_table != NULL) {
287 os::free((void*)_table);
288 _table = NULL;
289 }
290 }
291
292 // accessors
293 int size() const { return _size; }
294 JvmtiTagHashmapEntry** table() const { return _table; }
295 int entry_count() const { return _entry_count; }
296
297 // find an entry in the hashmap, returns NULL if not found.
298 inline JvmtiTagHashmapEntry* find(oop key) {
299 unsigned int h = hash(key);
300 JvmtiTagHashmapEntry* entry = _table[h];
301 while (entry != NULL) {
302 if (entry->object() == key) {
303 return entry;
304 }
305 entry = entry->next();
306 }
307 return NULL;
308 }
309
310
311 // add a new entry to hashmap
312 inline void add(oop key, JvmtiTagHashmapEntry* entry) {
313 assert(key != NULL, "checking");
314 assert(find(key) == NULL, "duplicate detected");
315 unsigned int h = hash(key);
316 JvmtiTagHashmapEntry* anchor = _table[h];
317 if (anchor == NULL) {
318 _table[h] = entry;
319 entry->set_next(NULL);
320 } else {
321 entry->set_next(anchor);
322 _table[h] = entry;
323 }
324
325 _entry_count++;
326 if (trace_threshold() > 0 && entry_count() >= trace_threshold()) {
327 assert(TraceJVMTIObjectTagging, "should only get here when tracing");
328 print_memory_usage();
329 compute_next_trace_threshold();
330 }
331
332 // if the number of entries exceed the threshold then resize
333 if (entry_count() > resize_threshold() && is_resizing_enabled()) {
334 resize();
335 }
336 }
337
338 // remove an entry with the given key.
339 inline JvmtiTagHashmapEntry* remove(oop key) {
340 unsigned int h = hash(key);
341 JvmtiTagHashmapEntry* entry = _table[h];
342 JvmtiTagHashmapEntry* prev = NULL;
343 while (entry != NULL) {
344 if (key == entry->object()) {
345 break;
346 }
347 prev = entry;
348 entry = entry->next();
349 }
350 if (entry != NULL) {
351 remove(prev, h, entry);
352 }
353 return entry;
354 }
355
356 // iterate over all entries in the hashmap
357 void entry_iterate(JvmtiTagHashmapEntryClosure* closure);
358 };
359
360 // possible hashmap sizes - odd primes that roughly double in size.
361 // To avoid excessive resizing the odd primes from 4801-76831 and
362 // 76831-307261 have been removed. The list must be terminated by -1.
363 int JvmtiTagHashmap::_sizes[] = { 4801, 76831, 307261, 614563, 1228891,
364 2457733, 4915219, 9830479, 19660831, 39321619, 78643219, -1 };
365
366
367 // A supporting class for iterating over all entries in Hashmap
368 class JvmtiTagHashmapEntryClosure {
369 public:
370 virtual void do_entry(JvmtiTagHashmapEntry* entry) = 0;
371 };
372
373
374 // iterate over all entries in the hashmap
375 void JvmtiTagHashmap::entry_iterate(JvmtiTagHashmapEntryClosure* closure) {
376 for (int i=0; i<_size; i++) {
377 JvmtiTagHashmapEntry* entry = _table[i];
378 JvmtiTagHashmapEntry* prev = NULL;
379 while (entry != NULL) {
380 // obtain the next entry before invoking do_entry - this is
381 // necessary because do_entry may remove the entry from the
382 // hashmap.
383 JvmtiTagHashmapEntry* next = entry->next();
384 closure->do_entry(entry);
385 entry = next;
386 }
387 }
388 }
389
390 // debugging
391 void JvmtiTagHashmap::print_memory_usage() {
392 intptr_t p = (intptr_t)this;
393 tty->print("[JvmtiTagHashmap @ " INTPTR_FORMAT, p);
394
395 // table + entries in KB
396 int hashmap_usage = (size()*sizeof(JvmtiTagHashmapEntry*) +
397 entry_count()*sizeof(JvmtiTagHashmapEntry))/K;
398
399 int weak_globals_usage = (int)(JNIHandles::weak_global_handle_memory_usage()/K);
400 tty->print_cr(", %d entries (%d KB) <JNI weak globals: %d KB>]",
401 entry_count(), hashmap_usage, weak_globals_usage);
402 }
403
404 // compute threshold for the next trace message
405 void JvmtiTagHashmap::compute_next_trace_threshold() {
406 if (trace_threshold() < medium_trace_threshold) {
407 _trace_threshold += small_trace_threshold;
408 } else {
409 if (trace_threshold() < large_trace_threshold) {
410 _trace_threshold += medium_trace_threshold;
411 } else {
412 _trace_threshold += large_trace_threshold;
413 }
414 }
415 }
416
417 // create a JvmtiTagMap
418 JvmtiTagMap::JvmtiTagMap(JvmtiEnv* env) :
419 _env(env),
420 _lock(Mutex::nonleaf+2, "JvmtiTagMap._lock", false),
421 _free_entries(NULL),
422 _free_entries_count(0)
423 {
424 assert(JvmtiThreadState_lock->is_locked(), "sanity check");
425 assert(((JvmtiEnvBase *)env)->tag_map() == NULL, "tag map already exists for environment");
426
427 _hashmap = new JvmtiTagHashmap();
428
429 // finally add us to the environment
430 ((JvmtiEnvBase *)env)->set_tag_map(this);
431 }
432
433
434 // destroy a JvmtiTagMap
435 JvmtiTagMap::~JvmtiTagMap() {
436
437 // no lock acquired as we assume the enclosing environment is
438 // also being destroryed.
439 ((JvmtiEnvBase *)_env)->set_tag_map(NULL);
440
441 JvmtiTagHashmapEntry** table = _hashmap->table();
442 for (int j = 0; j < _hashmap->size(); j++) {
443 JvmtiTagHashmapEntry* entry = table[j];
444 while (entry != NULL) {
445 JvmtiTagHashmapEntry* next = entry->next();
446 delete entry;
447 entry = next;
448 }
449 }
450
451 // finally destroy the hashmap
452 delete _hashmap;
453 _hashmap = NULL;
454
455 // remove any entries on the free list
456 JvmtiTagHashmapEntry* entry = _free_entries;
457 while (entry != NULL) {
458 JvmtiTagHashmapEntry* next = entry->next();
459 delete entry;
460 entry = next;
461 }
462 _free_entries = NULL;
463 }
464
465 // create a hashmap entry
466 // - if there's an entry on the (per-environment) free list then this
467 // is returned. Otherwise an new entry is allocated.
468 JvmtiTagHashmapEntry* JvmtiTagMap::create_entry(oop ref, jlong tag) {
469 assert(Thread::current()->is_VM_thread() || is_locked(), "checking");
470 JvmtiTagHashmapEntry* entry;
471 if (_free_entries == NULL) {
472 entry = new JvmtiTagHashmapEntry(ref, tag);
473 } else {
474 assert(_free_entries_count > 0, "mismatched _free_entries_count");
475 _free_entries_count--;
476 entry = _free_entries;
477 _free_entries = entry->next();
478 entry->init(ref, tag);
479 }
480 return entry;
481 }
482
483 // destroy an entry by returning it to the free list
484 void JvmtiTagMap::destroy_entry(JvmtiTagHashmapEntry* entry) {
485 assert(SafepointSynchronize::is_at_safepoint() || is_locked(), "checking");
486 // limit the size of the free list
487 if (_free_entries_count >= max_free_entries) {
488 delete entry;
489 } else {
490 entry->set_next(_free_entries);
491 _free_entries = entry;
492 _free_entries_count++;
493 }
494 }
495
496 // returns the tag map for the given environments. If the tag map
497 // doesn't exist then it is created.
498 JvmtiTagMap* JvmtiTagMap::tag_map_for(JvmtiEnv* env) {
499 JvmtiTagMap* tag_map = ((JvmtiEnvBase*)env)->tag_map();
500 if (tag_map == NULL) {
501 MutexLocker mu(JvmtiThreadState_lock);
502 tag_map = ((JvmtiEnvBase*)env)->tag_map();
503 if (tag_map == NULL) {
504 tag_map = new JvmtiTagMap(env);
505 }
506 } else {
507 CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
508 }
509 return tag_map;
510 }
511
512 // iterate over all entries in the tag map.
513 void JvmtiTagMap::entry_iterate(JvmtiTagHashmapEntryClosure* closure) {
514 hashmap()->entry_iterate(closure);
515 }
516
517 // returns true if the hashmaps are empty
518 bool JvmtiTagMap::is_empty() {
519 assert(SafepointSynchronize::is_at_safepoint() || is_locked(), "checking");
520 return hashmap()->entry_count() == 0;
521 }
522
523
524 // Return the tag value for an object, or 0 if the object is
525 // not tagged
526 //
527 static inline jlong tag_for(JvmtiTagMap* tag_map, oop o) {
528 JvmtiTagHashmapEntry* entry = tag_map->hashmap()->find(o);
529 if (entry == NULL) {
530 return 0;
531 } else {
532 return entry->tag();
533 }
534 }
535
536 // If the object is a java.lang.Class then return the klassOop,
537 // otherwise return the original object
538 static inline oop klassOop_if_java_lang_Class(oop o) {
539 if (o->klass() == SystemDictionary::Class_klass()) {
540 if (!java_lang_Class::is_primitive(o)) {
541 o = (oop)java_lang_Class::as_klassOop(o);
542 assert(o != NULL, "class for non-primitive mirror must exist");
543 }
544 }
545 return o;
546 }
547
548 // A CallbackWrapper is a support class for querying and tagging an object
549 // around a callback to a profiler. The constructor does pre-callback
550 // work to get the tag value, klass tag value, ... and the destructor
551 // does the post-callback work of tagging or untagging the object.
552 //
553 // {
554 // CallbackWrapper wrapper(tag_map, o);
555 //
556 // (*callback)(wrapper.klass_tag(), wrapper.obj_size(), wrapper.obj_tag_p(), ...)
557 //
558 // } // wrapper goes out of scope here which results in the destructor
559 // checking to see if the object has been tagged, untagged, or the
560 // tag value has changed.
561 //
562 class CallbackWrapper : public StackObj {
563 private:
564 JvmtiTagMap* _tag_map;
565 JvmtiTagHashmap* _hashmap;
566 JvmtiTagHashmapEntry* _entry;
567 oop _o;
568 jlong _obj_size;
569 jlong _obj_tag;
570 klassOop _klass; // the object's class
571 jlong _klass_tag;
572
573 protected:
574 JvmtiTagMap* tag_map() const { return _tag_map; }
575
576 // invoked post-callback to tag, untag, or update the tag of an object
577 void inline post_callback_tag_update(oop o, JvmtiTagHashmap* hashmap,
578 JvmtiTagHashmapEntry* entry, jlong obj_tag);
579 public:
580 CallbackWrapper(JvmtiTagMap* tag_map, oop o) {
581 assert(Thread::current()->is_VM_thread() || tag_map->is_locked(),
582 "MT unsafe or must be VM thread");
583
584 // for Classes the klassOop is tagged
585 _o = klassOop_if_java_lang_Class(o);
586
587 // object size
588 _obj_size = (jlong)_o->size() * wordSize;
589
590 // record the context
591 _tag_map = tag_map;
592 _hashmap = tag_map->hashmap();
593 _entry = _hashmap->find(_o);
594
595 // get object tag
596 _obj_tag = (_entry == NULL) ? 0 : _entry->tag();
597
598 // get the class and the class's tag value
599 if (_o == o) {
600 _klass = _o->klass();
601 } else {
602 // if the object represents a runtime class then use the
603 // tag for java.lang.Class
604 _klass = SystemDictionary::Class_klass();
605 }
606 _klass_tag = tag_for(tag_map, _klass);
607 }
608
609 ~CallbackWrapper() {
610 post_callback_tag_update(_o, _hashmap, _entry, _obj_tag);
611 }
612
613 inline jlong* obj_tag_p() { return &_obj_tag; }
614 inline jlong obj_size() const { return _obj_size; }
615 inline jlong obj_tag() const { return _obj_tag; }
616 inline klassOop klass() const { return _klass; }
617 inline jlong klass_tag() const { return _klass_tag; }
618 };
619
620
621
622 // callback post-callback to tag, untag, or update the tag of an object
623 void inline CallbackWrapper::post_callback_tag_update(oop o,
624 JvmtiTagHashmap* hashmap,
625 JvmtiTagHashmapEntry* entry,
626 jlong obj_tag) {
627 if (entry == NULL) {
628 if (obj_tag != 0) {
629 // callback has tagged the object
630 assert(Thread::current()->is_VM_thread(), "must be VMThread");
631 entry = tag_map()->create_entry(o, obj_tag);
632 hashmap->add(o, entry);
633 }
634 } else {
635 // object was previously tagged - the callback may have untagged
636 // the object or changed the tag value
637 if (obj_tag == 0) {
638
639 JvmtiTagHashmapEntry* entry_removed = hashmap->remove(o);
640 assert(entry_removed == entry, "checking");
641 tag_map()->destroy_entry(entry);
642
643 } else {
644 if (obj_tag != entry->tag()) {
645 entry->set_tag(obj_tag);
646 }
647 }
648 }
649 }
650
651 // An extended CallbackWrapper used when reporting an object reference
652 // to the agent.
653 //
654 // {
655 // TwoOopCallbackWrapper wrapper(tag_map, referrer, o);
656 //
657 // (*callback)(wrapper.klass_tag(),
658 // wrapper.obj_size(),
659 // wrapper.obj_tag_p()
660 // wrapper.referrer_tag_p(), ...)
661 //
662 // } // wrapper goes out of scope here which results in the destructor
663 // checking to see if the referrer object has been tagged, untagged,
664 // or the tag value has changed.
665 //
666 class TwoOopCallbackWrapper : public CallbackWrapper {
667 private:
668 bool _is_reference_to_self;
669 JvmtiTagHashmap* _referrer_hashmap;
670 JvmtiTagHashmapEntry* _referrer_entry;
671 oop _referrer;
672 jlong _referrer_obj_tag;
673 jlong _referrer_klass_tag;
674 jlong* _referrer_tag_p;
675
676 bool is_reference_to_self() const { return _is_reference_to_self; }
677
678 public:
679 TwoOopCallbackWrapper(JvmtiTagMap* tag_map, oop referrer, oop o) :
680 CallbackWrapper(tag_map, o)
681 {
682 // self reference needs to be handled in a special way
683 _is_reference_to_self = (referrer == o);
684
685 if (_is_reference_to_self) {
686 _referrer_klass_tag = klass_tag();
687 _referrer_tag_p = obj_tag_p();
688 } else {
689 // for Classes the klassOop is tagged
690 _referrer = klassOop_if_java_lang_Class(referrer);
691 // record the context
692 _referrer_hashmap = tag_map->hashmap();
693 _referrer_entry = _referrer_hashmap->find(_referrer);
694
695 // get object tag
696 _referrer_obj_tag = (_referrer_entry == NULL) ? 0 : _referrer_entry->tag();
697 _referrer_tag_p = &_referrer_obj_tag;
698
699 // get referrer class tag.
700 klassOop k = (_referrer == referrer) ? // Check if referrer is a class...
701 _referrer->klass() // No, just get its class
702 : SystemDictionary::Class_klass(); // Yes, its class is Class
703 _referrer_klass_tag = tag_for(tag_map, k);
704 }
705 }
706
707 ~TwoOopCallbackWrapper() {
708 if (!is_reference_to_self()){
709 post_callback_tag_update(_referrer,
710 _referrer_hashmap,
711 _referrer_entry,
712 _referrer_obj_tag);
713 }
714 }
715
716 // address of referrer tag
717 // (for a self reference this will return the same thing as obj_tag_p())
718 inline jlong* referrer_tag_p() { return _referrer_tag_p; }
719
720 // referrer's class tag
721 inline jlong referrer_klass_tag() { return _referrer_klass_tag; }
722 };
723
724 // tag an object
725 //
726 // This function is performance critical. If many threads attempt to tag objects
727 // around the same time then it's possible that the Mutex associated with the
728 // tag map will be a hot lock.
729 void JvmtiTagMap::set_tag(jobject object, jlong tag) {
730 MutexLocker ml(lock());
731
732 // resolve the object
733 oop o = JNIHandles::resolve_non_null(object);
734
735 // for Classes we tag the klassOop
736 o = klassOop_if_java_lang_Class(o);
737
738 // see if the object is already tagged
739 JvmtiTagHashmap* hashmap = _hashmap;
740 JvmtiTagHashmapEntry* entry = hashmap->find(o);
741
742 // if the object is not already tagged then we tag it
743 if (entry == NULL) {
744 if (tag != 0) {
745 entry = create_entry(o, tag);
746 hashmap->add(o, entry);
747 } else {
748 // no-op
749 }
750 } else {
751 // if the object is already tagged then we either update
752 // the tag (if a new tag value has been provided)
753 // or remove the object if the new tag value is 0.
754 if (tag == 0) {
755 hashmap->remove(o);
756 destroy_entry(entry);
757 } else {
758 entry->set_tag(tag);
759 }
760 }
761 }
762
763 // get the tag for an object
764 jlong JvmtiTagMap::get_tag(jobject object) {
765 MutexLocker ml(lock());
766
767 // resolve the object
768 oop o = JNIHandles::resolve_non_null(object);
769
770 // for Classes get the tag from the klassOop
771 return tag_for(this, klassOop_if_java_lang_Class(o));
772 }
773
774
775 // Helper class used to describe the static or instance fields of a class.
776 // For each field it holds the field index (as defined by the JVMTI specification),
777 // the field type, and the offset.
778
779 class ClassFieldDescriptor: public CHeapObj<mtInternal> {
780 private:
781 int _field_index;
782 int _field_offset;
783 char _field_type;
784 public:
785 ClassFieldDescriptor(int index, char type, int offset) :
786 _field_index(index), _field_type(type), _field_offset(offset) {
787 }
788 int field_index() const { return _field_index; }
789 char field_type() const { return _field_type; }
790 int field_offset() const { return _field_offset; }
791 };
792
793 class ClassFieldMap: public CHeapObj<mtInternal> {
794 private:
795 enum {
796 initial_field_count = 5
797 };
798
799 // list of field descriptors
800 GrowableArray<ClassFieldDescriptor*>* _fields;
801
802 // constructor
803 ClassFieldMap();
804
805 // add a field
806 void add(int index, char type, int offset);
807
808 // returns the field count for the given class
809 static int compute_field_count(instanceKlassHandle ikh);
810
811 public:
812 ~ClassFieldMap();
813
814 // access
815 int field_count() { return _fields->length(); }
816 ClassFieldDescriptor* field_at(int i) { return _fields->at(i); }
817
818 // functions to create maps of static or instance fields
819 static ClassFieldMap* create_map_of_static_fields(klassOop k);
820 static ClassFieldMap* create_map_of_instance_fields(oop obj);
821 };
822
823 ClassFieldMap::ClassFieldMap() {
824 _fields = new (ResourceObj::C_HEAP, mtInternal)
825 GrowableArray<ClassFieldDescriptor*>(initial_field_count, true);
826 }
827
828 ClassFieldMap::~ClassFieldMap() {
829 for (int i=0; i<_fields->length(); i++) {
830 delete _fields->at(i);
831 }
832 delete _fields;
833 }
834
835 void ClassFieldMap::add(int index, char type, int offset) {
836 ClassFieldDescriptor* field = new ClassFieldDescriptor(index, type, offset);
837 _fields->append(field);
838 }
839
840 // Returns a heap allocated ClassFieldMap to describe the static fields
841 // of the given class.
842 //
843 ClassFieldMap* ClassFieldMap::create_map_of_static_fields(klassOop k) {
844 HandleMark hm;
845 instanceKlassHandle ikh = instanceKlassHandle(Thread::current(), k);
846
847 // create the field map
848 ClassFieldMap* field_map = new ClassFieldMap();
849
850 FilteredFieldStream f(ikh, false, false);
851 int max_field_index = f.field_count()-1;
852
853 int index = 0;
854 for (FilteredFieldStream fld(ikh, true, true); !fld.eos(); fld.next(), index++) {
855 // ignore instance fields
856 if (!fld.access_flags().is_static()) {
857 continue;
858 }
859 field_map->add(max_field_index - index, fld.signature()->byte_at(0), fld.offset());
860 }
861 return field_map;
862 }
863
864 // Returns a heap allocated ClassFieldMap to describe the instance fields
865 // of the given class. All instance fields are included (this means public
866 // and private fields declared in superclasses and superinterfaces too).
867 //
868 ClassFieldMap* ClassFieldMap::create_map_of_instance_fields(oop obj) {
869 HandleMark hm;
870 instanceKlassHandle ikh = instanceKlassHandle(Thread::current(), obj->klass());
871
872 // create the field map
873 ClassFieldMap* field_map = new ClassFieldMap();
874
875 FilteredFieldStream f(ikh, false, false);
876
877 int max_field_index = f.field_count()-1;
878
879 int index = 0;
880 for (FilteredFieldStream fld(ikh, false, false); !fld.eos(); fld.next(), index++) {
881 // ignore static fields
882 if (fld.access_flags().is_static()) {
883 continue;
884 }
885 field_map->add(max_field_index - index, fld.signature()->byte_at(0), fld.offset());
886 }
887
888 return field_map;
889 }
890
891 // Helper class used to cache a ClassFileMap for the instance fields of
892 // a cache. A JvmtiCachedClassFieldMap can be cached by an instanceKlass during
893 // heap iteration and avoid creating a field map for each object in the heap
894 // (only need to create the map when the first instance of a class is encountered).
895 //
896 class JvmtiCachedClassFieldMap : public CHeapObj<mtInternal> {
897 private:
898 enum {
899 initial_class_count = 200
900 };
901 ClassFieldMap* _field_map;
902
903 ClassFieldMap* field_map() const { return _field_map; }
904
905 JvmtiCachedClassFieldMap(ClassFieldMap* field_map);
906 ~JvmtiCachedClassFieldMap();
907
908 static GrowableArray<instanceKlass*>* _class_list;
909 static void add_to_class_list(instanceKlass* ik);
910
911 public:
912 // returns the field map for a given object (returning map cached
913 // by instanceKlass if possible
914 static ClassFieldMap* get_map_of_instance_fields(oop obj);
915
916 // removes the field map from all instanceKlasses - should be
917 // called before VM operation completes
918 static void clear_cache();
919
920 // returns the number of ClassFieldMap cached by instanceKlasses
921 static int cached_field_map_count();
922 };
923
924 GrowableArray<instanceKlass*>* JvmtiCachedClassFieldMap::_class_list;
925
926 JvmtiCachedClassFieldMap::JvmtiCachedClassFieldMap(ClassFieldMap* field_map) {
927 _field_map = field_map;
928 }
929
930 JvmtiCachedClassFieldMap::~JvmtiCachedClassFieldMap() {
931 if (_field_map != NULL) {
932 delete _field_map;
933 }
934 }
935
936 // Marker class to ensure that the class file map cache is only used in a defined
937 // scope.
938 class ClassFieldMapCacheMark : public StackObj {
939 private:
940 static bool _is_active;
941 public:
942 ClassFieldMapCacheMark() {
943 assert(Thread::current()->is_VM_thread(), "must be VMThread");
944 assert(JvmtiCachedClassFieldMap::cached_field_map_count() == 0, "cache not empty");
945 assert(!_is_active, "ClassFieldMapCacheMark cannot be nested");
946 _is_active = true;
947 }
948 ~ClassFieldMapCacheMark() {
949 JvmtiCachedClassFieldMap::clear_cache();
950 _is_active = false;
951 }
952 static bool is_active() { return _is_active; }
953 };
954
955 bool ClassFieldMapCacheMark::_is_active;
956
957
958 // record that the given instanceKlass is caching a field map
959 void JvmtiCachedClassFieldMap::add_to_class_list(instanceKlass* ik) {
960 if (_class_list == NULL) {
961 _class_list = new (ResourceObj::C_HEAP, mtInternal)
962 GrowableArray<instanceKlass*>(initial_class_count, true);
963 }
964 _class_list->push(ik);
965 }
966
967 // returns the instance field map for the given object
968 // (returns field map cached by the instanceKlass if possible)
969 ClassFieldMap* JvmtiCachedClassFieldMap::get_map_of_instance_fields(oop obj) {
970 assert(Thread::current()->is_VM_thread(), "must be VMThread");
971 assert(ClassFieldMapCacheMark::is_active(), "ClassFieldMapCacheMark not active");
972
973 klassOop k = obj->klass();
974 instanceKlass* ik = instanceKlass::cast(k);
975
976 // return cached map if possible
977 JvmtiCachedClassFieldMap* cached_map = ik->jvmti_cached_class_field_map();
978 if (cached_map != NULL) {
979 assert(cached_map->field_map() != NULL, "missing field list");
980 return cached_map->field_map();
981 } else {
982 ClassFieldMap* field_map = ClassFieldMap::create_map_of_instance_fields(obj);
983 cached_map = new JvmtiCachedClassFieldMap(field_map);
984 ik->set_jvmti_cached_class_field_map(cached_map);
985 add_to_class_list(ik);
986 return field_map;
987 }
988 }
989
990 // remove the fields maps cached from all instanceKlasses
991 void JvmtiCachedClassFieldMap::clear_cache() {
992 assert(Thread::current()->is_VM_thread(), "must be VMThread");
993 if (_class_list != NULL) {
994 for (int i = 0; i < _class_list->length(); i++) {
995 instanceKlass* ik = _class_list->at(i);
996 JvmtiCachedClassFieldMap* cached_map = ik->jvmti_cached_class_field_map();
997 assert(cached_map != NULL, "should not be NULL");
998 ik->set_jvmti_cached_class_field_map(NULL);
999 delete cached_map; // deletes the encapsulated field map
1000 }
1001 delete _class_list;
1002 _class_list = NULL;
1003 }
1004 }
1005
1006 // returns the number of ClassFieldMap cached by instanceKlasses
1007 int JvmtiCachedClassFieldMap::cached_field_map_count() {
1008 return (_class_list == NULL) ? 0 : _class_list->length();
1009 }
1010
1011 // helper function to indicate if an object is filtered by its tag or class tag
1012 static inline bool is_filtered_by_heap_filter(jlong obj_tag,
1013 jlong klass_tag,
1014 int heap_filter) {
1015 // apply the heap filter
1016 if (obj_tag != 0) {
1017 // filter out tagged objects
1018 if (heap_filter & JVMTI_HEAP_FILTER_TAGGED) return true;
1019 } else {
1020 // filter out untagged objects
1021 if (heap_filter & JVMTI_HEAP_FILTER_UNTAGGED) return true;
1022 }
1023 if (klass_tag != 0) {
1024 // filter out objects with tagged classes
1025 if (heap_filter & JVMTI_HEAP_FILTER_CLASS_TAGGED) return true;
1026 } else {
1027 // filter out objects with untagged classes.
1028 if (heap_filter & JVMTI_HEAP_FILTER_CLASS_UNTAGGED) return true;
1029 }
1030 return false;
1031 }
1032
1033 // helper function to indicate if an object is filtered by a klass filter
1034 static inline bool is_filtered_by_klass_filter(oop obj, KlassHandle klass_filter) {
1035 if (!klass_filter.is_null()) {
1036 if (obj->klass() != klass_filter()) {
1037 return true;
1038 }
1039 }
1040 return false;
1041 }
1042
1043 // helper function to tell if a field is a primitive field or not
1044 static inline bool is_primitive_field_type(char type) {
1045 return (type != 'L' && type != '[');
1046 }
1047
1048 // helper function to copy the value from location addr to jvalue.
1049 static inline void copy_to_jvalue(jvalue *v, address addr, jvmtiPrimitiveType value_type) {
1050 switch (value_type) {
1051 case JVMTI_PRIMITIVE_TYPE_BOOLEAN : { v->z = *(jboolean*)addr; break; }
1052 case JVMTI_PRIMITIVE_TYPE_BYTE : { v->b = *(jbyte*)addr; break; }
1053 case JVMTI_PRIMITIVE_TYPE_CHAR : { v->c = *(jchar*)addr; break; }
1054 case JVMTI_PRIMITIVE_TYPE_SHORT : { v->s = *(jshort*)addr; break; }
1055 case JVMTI_PRIMITIVE_TYPE_INT : { v->i = *(jint*)addr; break; }
1056 case JVMTI_PRIMITIVE_TYPE_LONG : { v->j = *(jlong*)addr; break; }
1057 case JVMTI_PRIMITIVE_TYPE_FLOAT : { v->f = *(jfloat*)addr; break; }
1058 case JVMTI_PRIMITIVE_TYPE_DOUBLE : { v->d = *(jdouble*)addr; break; }
1059 default: ShouldNotReachHere();
1060 }
1061 }
1062
1063 // helper function to invoke string primitive value callback
1064 // returns visit control flags
1065 static jint invoke_string_value_callback(jvmtiStringPrimitiveValueCallback cb,
1066 CallbackWrapper* wrapper,
1067 oop str,
1068 void* user_data)
1069 {
1070 assert(str->klass() == SystemDictionary::String_klass(), "not a string");
1071
1072 // get the string value and length
1073 // (string value may be offset from the base)
1074 int s_len = java_lang_String::length(str);
1075 typeArrayOop s_value = java_lang_String::value(str);
1076 int s_offset = java_lang_String::offset(str);
1077 jchar* value;
1078 if (s_len > 0) {
1079 value = s_value->char_at_addr(s_offset);
1080 } else {
1081 value = (jchar*) s_value->base(T_CHAR);
1082 }
1083
1084 // invoke the callback
1085 return (*cb)(wrapper->klass_tag(),
1086 wrapper->obj_size(),
1087 wrapper->obj_tag_p(),
1088 value,
1089 (jint)s_len,
1090 user_data);
1091 }
1092
1093 // helper function to invoke string primitive value callback
1094 // returns visit control flags
1095 static jint invoke_array_primitive_value_callback(jvmtiArrayPrimitiveValueCallback cb,
1096 CallbackWrapper* wrapper,
1097 oop obj,
1098 void* user_data)
1099 {
1100 assert(obj->is_typeArray(), "not a primitive array");
1101
1102 // get base address of first element
1103 typeArrayOop array = typeArrayOop(obj);
1104 BasicType type = typeArrayKlass::cast(array->klass())->element_type();
1105 void* elements = array->base(type);
1106
1107 // jvmtiPrimitiveType is defined so this mapping is always correct
1108 jvmtiPrimitiveType elem_type = (jvmtiPrimitiveType)type2char(type);
1109
1110 return (*cb)(wrapper->klass_tag(),
1111 wrapper->obj_size(),
1112 wrapper->obj_tag_p(),
1113 (jint)array->length(),
1114 elem_type,
1115 elements,
1116 user_data);
1117 }
1118
1119 // helper function to invoke the primitive field callback for all static fields
1120 // of a given class
1121 static jint invoke_primitive_field_callback_for_static_fields
1122 (CallbackWrapper* wrapper,
1123 oop obj,
1124 jvmtiPrimitiveFieldCallback cb,
1125 void* user_data)
1126 {
1127 // for static fields only the index will be set
1128 static jvmtiHeapReferenceInfo reference_info = { 0 };
1129
1130 assert(obj->klass() == SystemDictionary::Class_klass(), "not a class");
1131 if (java_lang_Class::is_primitive(obj)) {
1132 return 0;
1133 }
1134 klassOop k = java_lang_Class::as_klassOop(obj);
1135 Klass* klass = k->klass_part();
1136
1137 // ignore classes for object and type arrays
1138 if (!klass->oop_is_instance()) {
1139 return 0;
1140 }
1141
1142 // ignore classes which aren't linked yet
1143 instanceKlass* ik = instanceKlass::cast(k);
1144 if (!ik->is_linked()) {
1145 return 0;
1146 }
1147
1148 // get the field map
1149 ClassFieldMap* field_map = ClassFieldMap::create_map_of_static_fields(k);
1150
1151 // invoke the callback for each static primitive field
1152 for (int i=0; i<field_map->field_count(); i++) {
1153 ClassFieldDescriptor* field = field_map->field_at(i);
1154
1155 // ignore non-primitive fields
1156 char type = field->field_type();
1157 if (!is_primitive_field_type(type)) {
1158 continue;
1159 }
1160 // one-to-one mapping
1161 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
1162
1163 // get offset and field value
1164 int offset = field->field_offset();
1165 address addr = (address)klass->java_mirror() + offset;
1166 jvalue value;
1167 copy_to_jvalue(&value, addr, value_type);
1168
1169 // field index
1170 reference_info.field.index = field->field_index();
1171
1172 // invoke the callback
1173 jint res = (*cb)(JVMTI_HEAP_REFERENCE_STATIC_FIELD,
1174 &reference_info,
1175 wrapper->klass_tag(),
1176 wrapper->obj_tag_p(),
1177 value,
1178 value_type,
1179 user_data);
1180 if (res & JVMTI_VISIT_ABORT) {
1181 delete field_map;
1182 return res;
1183 }
1184 }
1185
1186 delete field_map;
1187 return 0;
1188 }
1189
1190 // helper function to invoke the primitive field callback for all instance fields
1191 // of a given object
1192 static jint invoke_primitive_field_callback_for_instance_fields(
1193 CallbackWrapper* wrapper,
1194 oop obj,
1195 jvmtiPrimitiveFieldCallback cb,
1196 void* user_data)
1197 {
1198 // for instance fields only the index will be set
1199 static jvmtiHeapReferenceInfo reference_info = { 0 };
1200
1201 // get the map of the instance fields
1202 ClassFieldMap* fields = JvmtiCachedClassFieldMap::get_map_of_instance_fields(obj);
1203
1204 // invoke the callback for each instance primitive field
1205 for (int i=0; i<fields->field_count(); i++) {
1206 ClassFieldDescriptor* field = fields->field_at(i);
1207
1208 // ignore non-primitive fields
1209 char type = field->field_type();
1210 if (!is_primitive_field_type(type)) {
1211 continue;
1212 }
1213 // one-to-one mapping
1214 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
1215
1216 // get offset and field value
1217 int offset = field->field_offset();
1218 address addr = (address)obj + offset;
1219 jvalue value;
1220 copy_to_jvalue(&value, addr, value_type);
1221
1222 // field index
1223 reference_info.field.index = field->field_index();
1224
1225 // invoke the callback
1226 jint res = (*cb)(JVMTI_HEAP_REFERENCE_FIELD,
1227 &reference_info,
1228 wrapper->klass_tag(),
1229 wrapper->obj_tag_p(),
1230 value,
1231 value_type,
1232 user_data);
1233 if (res & JVMTI_VISIT_ABORT) {
1234 return res;
1235 }
1236 }
1237 return 0;
1238 }
1239
1240
1241 // VM operation to iterate over all objects in the heap (both reachable
1242 // and unreachable)
1243 class VM_HeapIterateOperation: public VM_Operation {
1244 private:
1245 ObjectClosure* _blk;
1246 public:
1247 VM_HeapIterateOperation(ObjectClosure* blk) { _blk = blk; }
1248
1249 VMOp_Type type() const { return VMOp_HeapIterateOperation; }
1250 void doit() {
1251 // allows class files maps to be cached during iteration
1252 ClassFieldMapCacheMark cm;
1253
1254 // make sure that heap is parsable (fills TLABs with filler objects)
1255 Universe::heap()->ensure_parsability(false); // no need to retire TLABs
1256
1257 // Verify heap before iteration - if the heap gets corrupted then
1258 // JVMTI's IterateOverHeap will crash.
1259 if (VerifyBeforeIteration) {
1260 Universe::verify();
1261 }
1262
1263 // do the iteration
1264 // If this operation encounters a bad object when using CMS,
1265 // consider using safe_object_iterate() which avoids perm gen
1266 // objects that may contain bad references.
1267 Universe::heap()->object_iterate(_blk);
1268
1269 // when sharing is enabled we must iterate over the shared spaces
1270 if (UseSharedSpaces) {
1271 GenCollectedHeap* gch = GenCollectedHeap::heap();
1272 CompactingPermGenGen* gen = (CompactingPermGenGen*)gch->perm_gen();
1273 gen->ro_space()->object_iterate(_blk);
1274 gen->rw_space()->object_iterate(_blk);
1275 }
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 KlassHandle _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 KlassHandle 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 KlassHandle 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 // ignore any objects that aren't visible to profiler
1327 if (!ServiceUtil::visible_oop(o)) return;
1328
1329 // instanceof check when filtering by klass
1330 if (!klass().is_null() && !o->is_a(klass()())) {
1331 return;
1332 }
1333 // prepare for the calllback
1334 CallbackWrapper wrapper(tag_map(), o);
1335
1336 // if the object is tagged and we're only interested in untagged objects
1337 // then don't invoke the callback. Similiarly, if the object is untagged
1338 // and we're only interested in tagged objects we skip the callback.
1339 if (wrapper.obj_tag() != 0) {
1340 if (object_filter() == JVMTI_HEAP_OBJECT_UNTAGGED) return;
1341 } else {
1342 if (object_filter() == JVMTI_HEAP_OBJECT_TAGGED) return;
1343 }
1344
1345 // invoke the agent's callback
1346 jvmtiIterationControl control = (*object_callback())(wrapper.klass_tag(),
1347 wrapper.obj_size(),
1348 wrapper.obj_tag_p(),
1349 (void*)user_data());
1350 if (control == JVMTI_ITERATION_ABORT) {
1351 set_iteration_aborted(true);
1352 }
1353 }
1354
1355 // An ObjectClosure used to support the IterateThroughHeap function
1356 class IterateThroughHeapObjectClosure: public ObjectClosure {
1357 private:
1358 JvmtiTagMap* _tag_map;
1359 KlassHandle _klass;
1360 int _heap_filter;
1361 const jvmtiHeapCallbacks* _callbacks;
1362 const void* _user_data;
1363
1364 // accessor functions
1365 JvmtiTagMap* tag_map() const { return _tag_map; }
1366 int heap_filter() const { return _heap_filter; }
1367 const jvmtiHeapCallbacks* callbacks() const { return _callbacks; }
1368 KlassHandle klass() const { return _klass; }
1369 const void* user_data() const { return _user_data; }
1370
1371 // indicates if the iteration has been aborted
1372 bool _iteration_aborted;
1373 bool is_iteration_aborted() const { return _iteration_aborted; }
1374
1375 // used to check the visit control flags. If the abort flag is set
1376 // then we set the iteration aborted flag so that the iteration completes
1377 // without processing any further objects
1378 bool check_flags_for_abort(jint flags) {
1379 bool is_abort = (flags & JVMTI_VISIT_ABORT) != 0;
1380 if (is_abort) {
1381 _iteration_aborted = true;
1382 }
1383 return is_abort;
1384 }
1385
1386 public:
1387 IterateThroughHeapObjectClosure(JvmtiTagMap* tag_map,
1388 KlassHandle klass,
1389 int heap_filter,
1390 const jvmtiHeapCallbacks* heap_callbacks,
1391 const void* user_data) :
1392 _tag_map(tag_map),
1393 _klass(klass),
1394 _heap_filter(heap_filter),
1395 _callbacks(heap_callbacks),
1396 _user_data(user_data),
1397 _iteration_aborted(false)
1398 {
1399 }
1400
1401 void do_object(oop o);
1402 };
1403
1404 // invoked for each object in the heap
1405 void IterateThroughHeapObjectClosure::do_object(oop obj) {
1406 // check if iteration has been halted
1407 if (is_iteration_aborted()) return;
1408
1409 // ignore any objects that aren't visible to profiler
1410 if (!ServiceUtil::visible_oop(obj)) return;
1411
1412 // apply class filter
1413 if (is_filtered_by_klass_filter(obj, klass())) return;
1414
1415 // prepare for callback
1416 CallbackWrapper wrapper(tag_map(), obj);
1417
1418 // check if filtered by the heap filter
1419 if (is_filtered_by_heap_filter(wrapper.obj_tag(), wrapper.klass_tag(), heap_filter())) {
1420 return;
1421 }
1422
1423 // for arrays we need the length, otherwise -1
1424 bool is_array = obj->is_array();
1425 int len = is_array ? arrayOop(obj)->length() : -1;
1426
1427 // invoke the object callback (if callback is provided)
1428 if (callbacks()->heap_iteration_callback != NULL) {
1429 jvmtiHeapIterationCallback cb = callbacks()->heap_iteration_callback;
1430 jint res = (*cb)(wrapper.klass_tag(),
1431 wrapper.obj_size(),
1432 wrapper.obj_tag_p(),
1433 (jint)len,
1434 (void*)user_data());
1435 if (check_flags_for_abort(res)) return;
1436 }
1437
1438 // for objects and classes we report primitive fields if callback provided
1439 if (callbacks()->primitive_field_callback != NULL && obj->is_instance()) {
1440 jint res;
1441 jvmtiPrimitiveFieldCallback cb = callbacks()->primitive_field_callback;
1442 if (obj->klass() == SystemDictionary::Class_klass()) {
1443 res = invoke_primitive_field_callback_for_static_fields(&wrapper,
1444 obj,
1445 cb,
1446 (void*)user_data());
1447 } else {
1448 res = invoke_primitive_field_callback_for_instance_fields(&wrapper,
1449 obj,
1450 cb,
1451 (void*)user_data());
1452 }
1453 if (check_flags_for_abort(res)) return;
1454 }
1455
1456 // string callback
1457 if (!is_array &&
1458 callbacks()->string_primitive_value_callback != NULL &&
1459 obj->klass() == SystemDictionary::String_klass()) {
1460 jint res = invoke_string_value_callback(
1461 callbacks()->string_primitive_value_callback,
1462 &wrapper,
1463 obj,
1464 (void*)user_data() );
1465 if (check_flags_for_abort(res)) return;
1466 }
1467
1468 // array callback
1469 if (is_array &&
1470 callbacks()->array_primitive_value_callback != NULL &&
1471 obj->is_typeArray()) {
1472 jint res = invoke_array_primitive_value_callback(
1473 callbacks()->array_primitive_value_callback,
1474 &wrapper,
1475 obj,
1476 (void*)user_data() );
1477 if (check_flags_for_abort(res)) return;
1478 }
1479 };
1480
1481
1482 // Deprecated function to iterate over all objects in the heap
1483 void JvmtiTagMap::iterate_over_heap(jvmtiHeapObjectFilter object_filter,
1484 KlassHandle klass,
1485 jvmtiHeapObjectCallback heap_object_callback,
1486 const void* user_data)
1487 {
1488 MutexLocker ml(Heap_lock);
1489 IterateOverHeapObjectClosure blk(this,
1490 klass,
1491 object_filter,
1492 heap_object_callback,
1493 user_data);
1494 VM_HeapIterateOperation op(&blk);
1495 VMThread::execute(&op);
1496 }
1497
1498
1499 // Iterates over all objects in the heap
1500 void JvmtiTagMap::iterate_through_heap(jint heap_filter,
1501 KlassHandle klass,
1502 const jvmtiHeapCallbacks* callbacks,
1503 const void* user_data)
1504 {
1505 MutexLocker ml(Heap_lock);
1506 IterateThroughHeapObjectClosure blk(this,
1507 klass,
1508 heap_filter,
1509 callbacks,
1510 user_data);
1511 VM_HeapIterateOperation op(&blk);
1512 VMThread::execute(&op);
1513 }
1514
1515 // support class for get_objects_with_tags
1516
1517 class TagObjectCollector : public JvmtiTagHashmapEntryClosure {
1518 private:
1519 JvmtiEnv* _env;
1520 jlong* _tags;
1521 jint _tag_count;
1522
1523 GrowableArray<jobject>* _object_results; // collected objects (JNI weak refs)
1524 GrowableArray<uint64_t>* _tag_results; // collected tags
1525
1526 public:
1527 TagObjectCollector(JvmtiEnv* env, const jlong* tags, jint tag_count) {
1528 _env = env;
1529 _tags = (jlong*)tags;
1530 _tag_count = tag_count;
1531 _object_results = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<jobject>(1,true);
1532 _tag_results = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<uint64_t>(1,true);
1533 }
1534
1535 ~TagObjectCollector() {
1536 delete _object_results;
1537 delete _tag_results;
1538 }
1539
1540 // for each tagged object check if the tag value matches
1541 // - if it matches then we create a JNI local reference to the object
1542 // and record the reference and tag value.
1543 //
1544 void do_entry(JvmtiTagHashmapEntry* entry) {
1545 for (int i=0; i<_tag_count; i++) {
1546 if (_tags[i] == entry->tag()) {
1547 oop o = entry->object();
1548 assert(o != NULL, "sanity check");
1549
1550 // the mirror is tagged
1551 if (o->is_klass()) {
1552 klassOop k = (klassOop)o;
1553 o = Klass::cast(k)->java_mirror();
1554 }
1555
1556 jobject ref = JNIHandles::make_local(JavaThread::current(), o);
1557 _object_results->append(ref);
1558 _tag_results->append((uint64_t)entry->tag());
1559 }
1560 }
1561 }
1562
1563 // return the results from the collection
1564 //
1565 jvmtiError result(jint* count_ptr, jobject** object_result_ptr, jlong** tag_result_ptr) {
1566 jvmtiError error;
1567 int count = _object_results->length();
1568 assert(count >= 0, "sanity check");
1569
1570 // if object_result_ptr is not NULL then allocate the result and copy
1571 // in the object references.
1572 if (object_result_ptr != NULL) {
1573 error = _env->Allocate(count * sizeof(jobject), (unsigned char**)object_result_ptr);
1574 if (error != JVMTI_ERROR_NONE) {
1575 return error;
1576 }
1577 for (int i=0; i<count; i++) {
1578 (*object_result_ptr)[i] = _object_results->at(i);
1579 }
1580 }
1581
1582 // if tag_result_ptr is not NULL then allocate the result and copy
1583 // in the tag values.
1584 if (tag_result_ptr != NULL) {
1585 error = _env->Allocate(count * sizeof(jlong), (unsigned char**)tag_result_ptr);
1586 if (error != JVMTI_ERROR_NONE) {
1587 if (object_result_ptr != NULL) {
1588 _env->Deallocate((unsigned char*)object_result_ptr);
1589 }
1590 return error;
1591 }
1592 for (int i=0; i<count; i++) {
1593 (*tag_result_ptr)[i] = (jlong)_tag_results->at(i);
1594 }
1595 }
1596
1597 *count_ptr = count;
1598 return JVMTI_ERROR_NONE;
1599 }
1600 };
1601
1602 // return the list of objects with the specified tags
1603 jvmtiError JvmtiTagMap::get_objects_with_tags(const jlong* tags,
1604 jint count, jint* count_ptr, jobject** object_result_ptr, jlong** tag_result_ptr) {
1605
1606 TagObjectCollector collector(env(), tags, count);
1607 {
1608 // iterate over all tagged objects
1609 MutexLocker ml(lock());
1610 entry_iterate(&collector);
1611 }
1612 return collector.result(count_ptr, object_result_ptr, tag_result_ptr);
1613 }
1614
1615
1616 // ObjectMarker is used to support the marking objects when walking the
1617 // heap.
1618 //
1619 // This implementation uses the existing mark bits in an object for
1620 // marking. Objects that are marked must later have their headers restored.
1621 // As most objects are unlocked and don't have their identity hash computed
1622 // we don't have to save their headers. Instead we save the headers that
1623 // are "interesting". Later when the headers are restored this implementation
1624 // restores all headers to their initial value and then restores the few
1625 // objects that had interesting headers.
1626 //
1627 // Future work: This implementation currently uses growable arrays to save
1628 // the oop and header of interesting objects. As an optimization we could
1629 // use the same technique as the GC and make use of the unused area
1630 // between top() and end().
1631 //
1632
1633 // An ObjectClosure used to restore the mark bits of an object
1634 class RestoreMarksClosure : public ObjectClosure {
1635 public:
1636 void do_object(oop o) {
1637 if (o != NULL) {
1638 markOop mark = o->mark();
1639 if (mark->is_marked()) {
1640 o->init_mark();
1641 }
1642 }
1643 }
1644 };
1645
1646 // ObjectMarker provides the mark and visited functions
1647 class ObjectMarker : AllStatic {
1648 private:
1649 // saved headers
1650 static GrowableArray<oop>* _saved_oop_stack;
1651 static GrowableArray<markOop>* _saved_mark_stack;
1652 static bool _needs_reset; // do we need to reset mark bits?
1653
1654 public:
1655 static void init(); // initialize
1656 static void done(); // clean-up
1657
1658 static inline void mark(oop o); // mark an object
1659 static inline bool visited(oop o); // check if object has been visited
1660
1661 static inline bool needs_reset() { return _needs_reset; }
1662 static inline void set_needs_reset(bool v) { _needs_reset = v; }
1663 };
1664
1665 GrowableArray<oop>* ObjectMarker::_saved_oop_stack = NULL;
1666 GrowableArray<markOop>* ObjectMarker::_saved_mark_stack = NULL;
1667 bool ObjectMarker::_needs_reset = true; // need to reset mark bits by default
1668
1669 // initialize ObjectMarker - prepares for object marking
1670 void ObjectMarker::init() {
1671 assert(Thread::current()->is_VM_thread(), "must be VMThread");
1672
1673 // prepare heap for iteration
1674 Universe::heap()->ensure_parsability(false); // no need to retire TLABs
1675
1676 // create stacks for interesting headers
1677 _saved_mark_stack = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<markOop>(4000, true);
1678 _saved_oop_stack = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(4000, true);
1679
1680 if (UseBiasedLocking) {
1681 BiasedLocking::preserve_marks();
1682 }
1683 }
1684
1685 // Object marking is done so restore object headers
1686 void ObjectMarker::done() {
1687 // iterate over all objects and restore the mark bits to
1688 // their initial value
1689 RestoreMarksClosure blk;
1690 if (needs_reset()) {
1691 Universe::heap()->object_iterate(&blk);
1692 } else {
1693 // We don't need to reset mark bits on this call, but reset the
1694 // flag to the default for the next call.
1695 set_needs_reset(true);
1696 }
1697
1698 // When sharing is enabled we need to restore the headers of the objects
1699 // in the readwrite space too.
1700 if (UseSharedSpaces) {
1701 GenCollectedHeap* gch = GenCollectedHeap::heap();
1702 CompactingPermGenGen* gen = (CompactingPermGenGen*)gch->perm_gen();
1703 gen->rw_space()->object_iterate(&blk);
1704 }
1705
1706 // now restore the interesting headers
1707 for (int i = 0; i < _saved_oop_stack->length(); i++) {
1708 oop o = _saved_oop_stack->at(i);
1709 markOop mark = _saved_mark_stack->at(i);
1710 o->set_mark(mark);
1711 }
1712
1713 if (UseBiasedLocking) {
1714 BiasedLocking::restore_marks();
1715 }
1716
1717 // free the stacks
1718 delete _saved_oop_stack;
1719 delete _saved_mark_stack;
1720 }
1721
1722 // mark an object
1723 inline void ObjectMarker::mark(oop o) {
1724 assert(Universe::heap()->is_in(o), "sanity check");
1725 assert(!o->mark()->is_marked(), "should only mark an object once");
1726
1727 // object's mark word
1728 markOop mark = o->mark();
1729
1730 if (mark->must_be_preserved(o)) {
1731 _saved_mark_stack->push(mark);
1732 _saved_oop_stack->push(o);
1733 }
1734
1735 // mark the object
1736 o->set_mark(markOopDesc::prototype()->set_marked());
1737 }
1738
1739 // return true if object is marked
1740 inline bool ObjectMarker::visited(oop o) {
1741 return o->mark()->is_marked();
1742 }
1743
1744 // Stack allocated class to help ensure that ObjectMarker is used
1745 // correctly. Constructor initializes ObjectMarker, destructor calls
1746 // ObjectMarker's done() function to restore object headers.
1747 class ObjectMarkerController : public StackObj {
1748 public:
1749 ObjectMarkerController() {
1750 ObjectMarker::init();
1751 }
1752 ~ObjectMarkerController() {
1753 ObjectMarker::done();
1754 }
1755 };
1756
1757
1758 // helper to map a jvmtiHeapReferenceKind to an old style jvmtiHeapRootKind
1759 // (not performance critical as only used for roots)
1760 static jvmtiHeapRootKind toJvmtiHeapRootKind(jvmtiHeapReferenceKind kind) {
1761 switch (kind) {
1762 case JVMTI_HEAP_REFERENCE_JNI_GLOBAL: return JVMTI_HEAP_ROOT_JNI_GLOBAL;
1763 case JVMTI_HEAP_REFERENCE_SYSTEM_CLASS: return JVMTI_HEAP_ROOT_SYSTEM_CLASS;
1764 case JVMTI_HEAP_REFERENCE_MONITOR: return JVMTI_HEAP_ROOT_MONITOR;
1765 case JVMTI_HEAP_REFERENCE_STACK_LOCAL: return JVMTI_HEAP_ROOT_STACK_LOCAL;
1766 case JVMTI_HEAP_REFERENCE_JNI_LOCAL: return JVMTI_HEAP_ROOT_JNI_LOCAL;
1767 case JVMTI_HEAP_REFERENCE_THREAD: return JVMTI_HEAP_ROOT_THREAD;
1768 case JVMTI_HEAP_REFERENCE_OTHER: return JVMTI_HEAP_ROOT_OTHER;
1769 default: ShouldNotReachHere(); return JVMTI_HEAP_ROOT_OTHER;
1770 }
1771 }
1772
1773 // Base class for all heap walk contexts. The base class maintains a flag
1774 // to indicate if the context is valid or not.
1775 class HeapWalkContext VALUE_OBJ_CLASS_SPEC {
1776 private:
1777 bool _valid;
1778 public:
1779 HeapWalkContext(bool valid) { _valid = valid; }
1780 void invalidate() { _valid = false; }
1781 bool is_valid() const { return _valid; }
1782 };
1783
1784 // A basic heap walk context for the deprecated heap walking functions.
1785 // The context for a basic heap walk are the callbacks and fields used by
1786 // the referrer caching scheme.
1787 class BasicHeapWalkContext: public HeapWalkContext {
1788 private:
1789 jvmtiHeapRootCallback _heap_root_callback;
1790 jvmtiStackReferenceCallback _stack_ref_callback;
1791 jvmtiObjectReferenceCallback _object_ref_callback;
1792
1793 // used for caching
1794 oop _last_referrer;
1795 jlong _last_referrer_tag;
1796
1797 public:
1798 BasicHeapWalkContext() : HeapWalkContext(false) { }
1799
1800 BasicHeapWalkContext(jvmtiHeapRootCallback heap_root_callback,
1801 jvmtiStackReferenceCallback stack_ref_callback,
1802 jvmtiObjectReferenceCallback object_ref_callback) :
1803 HeapWalkContext(true),
1804 _heap_root_callback(heap_root_callback),
1805 _stack_ref_callback(stack_ref_callback),
1806 _object_ref_callback(object_ref_callback),
1807 _last_referrer(NULL),
1808 _last_referrer_tag(0) {
1809 }
1810
1811 // accessors
1812 jvmtiHeapRootCallback heap_root_callback() const { return _heap_root_callback; }
1813 jvmtiStackReferenceCallback stack_ref_callback() const { return _stack_ref_callback; }
1814 jvmtiObjectReferenceCallback object_ref_callback() const { return _object_ref_callback; }
1815
1816 oop last_referrer() const { return _last_referrer; }
1817 void set_last_referrer(oop referrer) { _last_referrer = referrer; }
1818 jlong last_referrer_tag() const { return _last_referrer_tag; }
1819 void set_last_referrer_tag(jlong value) { _last_referrer_tag = value; }
1820 };
1821
1822 // The advanced heap walk context for the FollowReferences functions.
1823 // The context is the callbacks, and the fields used for filtering.
1824 class AdvancedHeapWalkContext: public HeapWalkContext {
1825 private:
1826 jint _heap_filter;
1827 KlassHandle _klass_filter;
1828 const jvmtiHeapCallbacks* _heap_callbacks;
1829
1830 public:
1831 AdvancedHeapWalkContext() : HeapWalkContext(false) { }
1832
1833 AdvancedHeapWalkContext(jint heap_filter,
1834 KlassHandle klass_filter,
1835 const jvmtiHeapCallbacks* heap_callbacks) :
1836 HeapWalkContext(true),
1837 _heap_filter(heap_filter),
1838 _klass_filter(klass_filter),
1839 _heap_callbacks(heap_callbacks) {
1840 }
1841
1842 // accessors
1843 jint heap_filter() const { return _heap_filter; }
1844 KlassHandle klass_filter() const { return _klass_filter; }
1845
1846 const jvmtiHeapReferenceCallback heap_reference_callback() const {
1847 return _heap_callbacks->heap_reference_callback;
1848 };
1849 const jvmtiPrimitiveFieldCallback primitive_field_callback() const {
1850 return _heap_callbacks->primitive_field_callback;
1851 }
1852 const jvmtiArrayPrimitiveValueCallback array_primitive_value_callback() const {
1853 return _heap_callbacks->array_primitive_value_callback;
1854 }
1855 const jvmtiStringPrimitiveValueCallback string_primitive_value_callback() const {
1856 return _heap_callbacks->string_primitive_value_callback;
1857 }
1858 };
1859
1860 // The CallbackInvoker is a class with static functions that the heap walk can call
1861 // into to invoke callbacks. It works in one of two modes. The "basic" mode is
1862 // used for the deprecated IterateOverReachableObjects functions. The "advanced"
1863 // mode is for the newer FollowReferences function which supports a lot of
1864 // additional callbacks.
1865 class CallbackInvoker : AllStatic {
1866 private:
1867 // heap walk styles
1868 enum { basic, advanced };
1869 static int _heap_walk_type;
1870 static bool is_basic_heap_walk() { return _heap_walk_type == basic; }
1871 static bool is_advanced_heap_walk() { return _heap_walk_type == advanced; }
1872
1873 // context for basic style heap walk
1874 static BasicHeapWalkContext _basic_context;
1875 static BasicHeapWalkContext* basic_context() {
1876 assert(_basic_context.is_valid(), "invalid");
1877 return &_basic_context;
1878 }
1879
1880 // context for advanced style heap walk
1881 static AdvancedHeapWalkContext _advanced_context;
1882 static AdvancedHeapWalkContext* advanced_context() {
1883 assert(_advanced_context.is_valid(), "invalid");
1884 return &_advanced_context;
1885 }
1886
1887 // context needed for all heap walks
1888 static JvmtiTagMap* _tag_map;
1889 static const void* _user_data;
1890 static GrowableArray<oop>* _visit_stack;
1891
1892 // accessors
1893 static JvmtiTagMap* tag_map() { return _tag_map; }
1894 static const void* user_data() { return _user_data; }
1895 static GrowableArray<oop>* visit_stack() { return _visit_stack; }
1896
1897 // if the object hasn't been visited then push it onto the visit stack
1898 // so that it will be visited later
1899 static inline bool check_for_visit(oop obj) {
1900 if (!ObjectMarker::visited(obj)) visit_stack()->push(obj);
1901 return true;
1902 }
1903
1904 // invoke basic style callbacks
1905 static inline bool invoke_basic_heap_root_callback
1906 (jvmtiHeapRootKind root_kind, oop obj);
1907 static inline bool invoke_basic_stack_ref_callback
1908 (jvmtiHeapRootKind root_kind, jlong thread_tag, jint depth, jmethodID method,
1909 int slot, oop obj);
1910 static inline bool invoke_basic_object_reference_callback
1911 (jvmtiObjectReferenceKind ref_kind, oop referrer, oop referree, jint index);
1912
1913 // invoke advanced style callbacks
1914 static inline bool invoke_advanced_heap_root_callback
1915 (jvmtiHeapReferenceKind ref_kind, oop obj);
1916 static inline bool invoke_advanced_stack_ref_callback
1917 (jvmtiHeapReferenceKind ref_kind, jlong thread_tag, jlong tid, int depth,
1918 jmethodID method, jlocation bci, jint slot, oop obj);
1919 static inline bool invoke_advanced_object_reference_callback
1920 (jvmtiHeapReferenceKind ref_kind, oop referrer, oop referree, jint index);
1921
1922 // used to report the value of primitive fields
1923 static inline bool report_primitive_field
1924 (jvmtiHeapReferenceKind ref_kind, oop obj, jint index, address addr, char type);
1925
1926 public:
1927 // initialize for basic mode
1928 static void initialize_for_basic_heap_walk(JvmtiTagMap* tag_map,
1929 GrowableArray<oop>* visit_stack,
1930 const void* user_data,
1931 BasicHeapWalkContext context);
1932
1933 // initialize for advanced mode
1934 static void initialize_for_advanced_heap_walk(JvmtiTagMap* tag_map,
1935 GrowableArray<oop>* visit_stack,
1936 const void* user_data,
1937 AdvancedHeapWalkContext context);
1938
1939 // functions to report roots
1940 static inline bool report_simple_root(jvmtiHeapReferenceKind kind, oop o);
1941 static inline bool report_jni_local_root(jlong thread_tag, jlong tid, jint depth,
1942 jmethodID m, oop o);
1943 static inline bool report_stack_ref_root(jlong thread_tag, jlong tid, jint depth,
1944 jmethodID method, jlocation bci, jint slot, oop o);
1945
1946 // functions to report references
1947 static inline bool report_array_element_reference(oop referrer, oop referree, jint index);
1948 static inline bool report_class_reference(oop referrer, oop referree);
1949 static inline bool report_class_loader_reference(oop referrer, oop referree);
1950 static inline bool report_signers_reference(oop referrer, oop referree);
1951 static inline bool report_protection_domain_reference(oop referrer, oop referree);
1952 static inline bool report_superclass_reference(oop referrer, oop referree);
1953 static inline bool report_interface_reference(oop referrer, oop referree);
1954 static inline bool report_static_field_reference(oop referrer, oop referree, jint slot);
1955 static inline bool report_field_reference(oop referrer, oop referree, jint slot);
1956 static inline bool report_constant_pool_reference(oop referrer, oop referree, jint index);
1957 static inline bool report_primitive_array_values(oop array);
1958 static inline bool report_string_value(oop str);
1959 static inline bool report_primitive_instance_field(oop o, jint index, address value, char type);
1960 static inline bool report_primitive_static_field(oop o, jint index, address value, char type);
1961 };
1962
1963 // statics
1964 int CallbackInvoker::_heap_walk_type;
1965 BasicHeapWalkContext CallbackInvoker::_basic_context;
1966 AdvancedHeapWalkContext CallbackInvoker::_advanced_context;
1967 JvmtiTagMap* CallbackInvoker::_tag_map;
1968 const void* CallbackInvoker::_user_data;
1969 GrowableArray<oop>* CallbackInvoker::_visit_stack;
1970
1971 // initialize for basic heap walk (IterateOverReachableObjects et al)
1972 void CallbackInvoker::initialize_for_basic_heap_walk(JvmtiTagMap* tag_map,
1973 GrowableArray<oop>* visit_stack,
1974 const void* user_data,
1975 BasicHeapWalkContext context) {
1976 _tag_map = tag_map;
1977 _visit_stack = visit_stack;
1978 _user_data = user_data;
1979 _basic_context = context;
1980 _advanced_context.invalidate(); // will trigger assertion if used
1981 _heap_walk_type = basic;
1982 }
1983
1984 // initialize for advanced heap walk (FollowReferences)
1985 void CallbackInvoker::initialize_for_advanced_heap_walk(JvmtiTagMap* tag_map,
1986 GrowableArray<oop>* visit_stack,
1987 const void* user_data,
1988 AdvancedHeapWalkContext context) {
1989 _tag_map = tag_map;
1990 _visit_stack = visit_stack;
1991 _user_data = user_data;
1992 _advanced_context = context;
1993 _basic_context.invalidate(); // will trigger assertion if used
1994 _heap_walk_type = advanced;
1995 }
1996
1997
1998 // invoke basic style heap root callback
1999 inline bool CallbackInvoker::invoke_basic_heap_root_callback(jvmtiHeapRootKind root_kind, oop obj) {
2000 assert(ServiceUtil::visible_oop(obj), "checking");
2001
2002 // if we heap roots should be reported
2003 jvmtiHeapRootCallback cb = basic_context()->heap_root_callback();
2004 if (cb == NULL) {
2005 return check_for_visit(obj);
2006 }
2007
2008 CallbackWrapper wrapper(tag_map(), obj);
2009 jvmtiIterationControl control = (*cb)(root_kind,
2010 wrapper.klass_tag(),
2011 wrapper.obj_size(),
2012 wrapper.obj_tag_p(),
2013 (void*)user_data());
2014 // push root to visit stack when following references
2015 if (control == JVMTI_ITERATION_CONTINUE &&
2016 basic_context()->object_ref_callback() != NULL) {
2017 visit_stack()->push(obj);
2018 }
2019 return control != JVMTI_ITERATION_ABORT;
2020 }
2021
2022 // invoke basic style stack ref callback
2023 inline bool CallbackInvoker::invoke_basic_stack_ref_callback(jvmtiHeapRootKind root_kind,
2024 jlong thread_tag,
2025 jint depth,
2026 jmethodID method,
2027 jint slot,
2028 oop obj) {
2029 assert(ServiceUtil::visible_oop(obj), "checking");
2030
2031 // if we stack refs should be reported
2032 jvmtiStackReferenceCallback cb = basic_context()->stack_ref_callback();
2033 if (cb == NULL) {
2034 return check_for_visit(obj);
2035 }
2036
2037 CallbackWrapper wrapper(tag_map(), obj);
2038 jvmtiIterationControl control = (*cb)(root_kind,
2039 wrapper.klass_tag(),
2040 wrapper.obj_size(),
2041 wrapper.obj_tag_p(),
2042 thread_tag,
2043 depth,
2044 method,
2045 slot,
2046 (void*)user_data());
2047 // push root to visit stack when following references
2048 if (control == JVMTI_ITERATION_CONTINUE &&
2049 basic_context()->object_ref_callback() != NULL) {
2050 visit_stack()->push(obj);
2051 }
2052 return control != JVMTI_ITERATION_ABORT;
2053 }
2054
2055 // invoke basic style object reference callback
2056 inline bool CallbackInvoker::invoke_basic_object_reference_callback(jvmtiObjectReferenceKind ref_kind,
2057 oop referrer,
2058 oop referree,
2059 jint index) {
2060
2061 assert(ServiceUtil::visible_oop(referrer), "checking");
2062 assert(ServiceUtil::visible_oop(referree), "checking");
2063
2064 BasicHeapWalkContext* context = basic_context();
2065
2066 // callback requires the referrer's tag. If it's the same referrer
2067 // as the last call then we use the cached value.
2068 jlong referrer_tag;
2069 if (referrer == context->last_referrer()) {
2070 referrer_tag = context->last_referrer_tag();
2071 } else {
2072 referrer_tag = tag_for(tag_map(), klassOop_if_java_lang_Class(referrer));
2073 }
2074
2075 // do the callback
2076 CallbackWrapper wrapper(tag_map(), referree);
2077 jvmtiObjectReferenceCallback cb = context->object_ref_callback();
2078 jvmtiIterationControl control = (*cb)(ref_kind,
2079 wrapper.klass_tag(),
2080 wrapper.obj_size(),
2081 wrapper.obj_tag_p(),
2082 referrer_tag,
2083 index,
2084 (void*)user_data());
2085
2086 // record referrer and referrer tag. For self-references record the
2087 // tag value from the callback as this might differ from referrer_tag.
2088 context->set_last_referrer(referrer);
2089 if (referrer == referree) {
2090 context->set_last_referrer_tag(*wrapper.obj_tag_p());
2091 } else {
2092 context->set_last_referrer_tag(referrer_tag);
2093 }
2094
2095 if (control == JVMTI_ITERATION_CONTINUE) {
2096 return check_for_visit(referree);
2097 } else {
2098 return control != JVMTI_ITERATION_ABORT;
2099 }
2100 }
2101
2102 // invoke advanced style heap root callback
2103 inline bool CallbackInvoker::invoke_advanced_heap_root_callback(jvmtiHeapReferenceKind ref_kind,
2104 oop obj) {
2105 assert(ServiceUtil::visible_oop(obj), "checking");
2106
2107 AdvancedHeapWalkContext* context = advanced_context();
2108
2109 // check that callback is provided
2110 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
2111 if (cb == NULL) {
2112 return check_for_visit(obj);
2113 }
2114
2115 // apply class filter
2116 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2117 return check_for_visit(obj);
2118 }
2119
2120 // setup the callback wrapper
2121 CallbackWrapper wrapper(tag_map(), obj);
2122
2123 // apply tag filter
2124 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2125 wrapper.klass_tag(),
2126 context->heap_filter())) {
2127 return check_for_visit(obj);
2128 }
2129
2130 // for arrays we need the length, otherwise -1
2131 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
2132
2133 // invoke the callback
2134 jint res = (*cb)(ref_kind,
2135 NULL, // referrer info
2136 wrapper.klass_tag(),
2137 0, // referrer_class_tag is 0 for heap root
2138 wrapper.obj_size(),
2139 wrapper.obj_tag_p(),
2140 NULL, // referrer_tag_p
2141 len,
2142 (void*)user_data());
2143 if (res & JVMTI_VISIT_ABORT) {
2144 return false;// referrer class tag
2145 }
2146 if (res & JVMTI_VISIT_OBJECTS) {
2147 check_for_visit(obj);
2148 }
2149 return true;
2150 }
2151
2152 // report a reference from a thread stack to an object
2153 inline bool CallbackInvoker::invoke_advanced_stack_ref_callback(jvmtiHeapReferenceKind ref_kind,
2154 jlong thread_tag,
2155 jlong tid,
2156 int depth,
2157 jmethodID method,
2158 jlocation bci,
2159 jint slot,
2160 oop obj) {
2161 assert(ServiceUtil::visible_oop(obj), "checking");
2162
2163 AdvancedHeapWalkContext* context = advanced_context();
2164
2165 // check that callback is provider
2166 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
2167 if (cb == NULL) {
2168 return check_for_visit(obj);
2169 }
2170
2171 // apply class filter
2172 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2173 return check_for_visit(obj);
2174 }
2175
2176 // setup the callback wrapper
2177 CallbackWrapper wrapper(tag_map(), obj);
2178
2179 // apply tag filter
2180 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2181 wrapper.klass_tag(),
2182 context->heap_filter())) {
2183 return check_for_visit(obj);
2184 }
2185
2186 // setup the referrer info
2187 jvmtiHeapReferenceInfo reference_info;
2188 reference_info.stack_local.thread_tag = thread_tag;
2189 reference_info.stack_local.thread_id = tid;
2190 reference_info.stack_local.depth = depth;
2191 reference_info.stack_local.method = method;
2192 reference_info.stack_local.location = bci;
2193 reference_info.stack_local.slot = slot;
2194
2195 // for arrays we need the length, otherwise -1
2196 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
2197
2198 // call into the agent
2199 int res = (*cb)(ref_kind,
2200 &reference_info,
2201 wrapper.klass_tag(),
2202 0, // referrer_class_tag is 0 for heap root (stack)
2203 wrapper.obj_size(),
2204 wrapper.obj_tag_p(),
2205 NULL, // referrer_tag is 0 for root
2206 len,
2207 (void*)user_data());
2208
2209 if (res & JVMTI_VISIT_ABORT) {
2210 return false;
2211 }
2212 if (res & JVMTI_VISIT_OBJECTS) {
2213 check_for_visit(obj);
2214 }
2215 return true;
2216 }
2217
2218 // This mask is used to pass reference_info to a jvmtiHeapReferenceCallback
2219 // only for ref_kinds defined by the JVM TI spec. Otherwise, NULL is passed.
2220 #define REF_INFO_MASK ((1 << JVMTI_HEAP_REFERENCE_FIELD) \
2221 | (1 << JVMTI_HEAP_REFERENCE_STATIC_FIELD) \
2222 | (1 << JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT) \
2223 | (1 << JVMTI_HEAP_REFERENCE_CONSTANT_POOL) \
2224 | (1 << JVMTI_HEAP_REFERENCE_STACK_LOCAL) \
2225 | (1 << JVMTI_HEAP_REFERENCE_JNI_LOCAL))
2226
2227 // invoke the object reference callback to report a reference
2228 inline bool CallbackInvoker::invoke_advanced_object_reference_callback(jvmtiHeapReferenceKind ref_kind,
2229 oop referrer,
2230 oop obj,
2231 jint index)
2232 {
2233 // field index is only valid field in reference_info
2234 static jvmtiHeapReferenceInfo reference_info = { 0 };
2235
2236 assert(ServiceUtil::visible_oop(referrer), "checking");
2237 assert(ServiceUtil::visible_oop(obj), "checking");
2238
2239 AdvancedHeapWalkContext* context = advanced_context();
2240
2241 // check that callback is provider
2242 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
2243 if (cb == NULL) {
2244 return check_for_visit(obj);
2245 }
2246
2247 // apply class filter
2248 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2249 return check_for_visit(obj);
2250 }
2251
2252 // setup the callback wrapper
2253 TwoOopCallbackWrapper wrapper(tag_map(), referrer, obj);
2254
2255 // apply tag filter
2256 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2257 wrapper.klass_tag(),
2258 context->heap_filter())) {
2259 return check_for_visit(obj);
2260 }
2261
2262 // field index is only valid field in reference_info
2263 reference_info.field.index = index;
2264
2265 // for arrays we need the length, otherwise -1
2266 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
2267
2268 // invoke the callback
2269 int res = (*cb)(ref_kind,
2270 (REF_INFO_MASK & (1 << ref_kind)) ? &reference_info : NULL,
2271 wrapper.klass_tag(),
2272 wrapper.referrer_klass_tag(),
2273 wrapper.obj_size(),
2274 wrapper.obj_tag_p(),
2275 wrapper.referrer_tag_p(),
2276 len,
2277 (void*)user_data());
2278
2279 if (res & JVMTI_VISIT_ABORT) {
2280 return false;
2281 }
2282 if (res & JVMTI_VISIT_OBJECTS) {
2283 check_for_visit(obj);
2284 }
2285 return true;
2286 }
2287
2288 // report a "simple root"
2289 inline bool CallbackInvoker::report_simple_root(jvmtiHeapReferenceKind kind, oop obj) {
2290 assert(kind != JVMTI_HEAP_REFERENCE_STACK_LOCAL &&
2291 kind != JVMTI_HEAP_REFERENCE_JNI_LOCAL, "not a simple root");
2292 assert(ServiceUtil::visible_oop(obj), "checking");
2293
2294 if (is_basic_heap_walk()) {
2295 // map to old style root kind
2296 jvmtiHeapRootKind root_kind = toJvmtiHeapRootKind(kind);
2297 return invoke_basic_heap_root_callback(root_kind, obj);
2298 } else {
2299 assert(is_advanced_heap_walk(), "wrong heap walk type");
2300 return invoke_advanced_heap_root_callback(kind, obj);
2301 }
2302 }
2303
2304
2305 // invoke the primitive array values
2306 inline bool CallbackInvoker::report_primitive_array_values(oop obj) {
2307 assert(obj->is_typeArray(), "not a primitive array");
2308
2309 AdvancedHeapWalkContext* context = advanced_context();
2310 assert(context->array_primitive_value_callback() != NULL, "no callback");
2311
2312 // apply class filter
2313 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2314 return true;
2315 }
2316
2317 CallbackWrapper wrapper(tag_map(), obj);
2318
2319 // apply tag filter
2320 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2321 wrapper.klass_tag(),
2322 context->heap_filter())) {
2323 return true;
2324 }
2325
2326 // invoke the callback
2327 int res = invoke_array_primitive_value_callback(context->array_primitive_value_callback(),
2328 &wrapper,
2329 obj,
2330 (void*)user_data());
2331 return (!(res & JVMTI_VISIT_ABORT));
2332 }
2333
2334 // invoke the string value callback
2335 inline bool CallbackInvoker::report_string_value(oop str) {
2336 assert(str->klass() == SystemDictionary::String_klass(), "not a string");
2337
2338 AdvancedHeapWalkContext* context = advanced_context();
2339 assert(context->string_primitive_value_callback() != NULL, "no callback");
2340
2341 // apply class filter
2342 if (is_filtered_by_klass_filter(str, context->klass_filter())) {
2343 return true;
2344 }
2345
2346 CallbackWrapper wrapper(tag_map(), str);
2347
2348 // apply tag filter
2349 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2350 wrapper.klass_tag(),
2351 context->heap_filter())) {
2352 return true;
2353 }
2354
2355 // invoke the callback
2356 int res = invoke_string_value_callback(context->string_primitive_value_callback(),
2357 &wrapper,
2358 str,
2359 (void*)user_data());
2360 return (!(res & JVMTI_VISIT_ABORT));
2361 }
2362
2363 // invoke the primitive field callback
2364 inline bool CallbackInvoker::report_primitive_field(jvmtiHeapReferenceKind ref_kind,
2365 oop obj,
2366 jint index,
2367 address addr,
2368 char type)
2369 {
2370 // for primitive fields only the index will be set
2371 static jvmtiHeapReferenceInfo reference_info = { 0 };
2372
2373 AdvancedHeapWalkContext* context = advanced_context();
2374 assert(context->primitive_field_callback() != NULL, "no callback");
2375
2376 // apply class filter
2377 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2378 return true;
2379 }
2380
2381 CallbackWrapper wrapper(tag_map(), obj);
2382
2383 // apply tag filter
2384 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2385 wrapper.klass_tag(),
2386 context->heap_filter())) {
2387 return true;
2388 }
2389
2390 // the field index in the referrer
2391 reference_info.field.index = index;
2392
2393 // map the type
2394 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
2395
2396 // setup the jvalue
2397 jvalue value;
2398 copy_to_jvalue(&value, addr, value_type);
2399
2400 jvmtiPrimitiveFieldCallback cb = context->primitive_field_callback();
2401 int res = (*cb)(ref_kind,
2402 &reference_info,
2403 wrapper.klass_tag(),
2404 wrapper.obj_tag_p(),
2405 value,
2406 value_type,
2407 (void*)user_data());
2408 return (!(res & JVMTI_VISIT_ABORT));
2409 }
2410
2411
2412 // instance field
2413 inline bool CallbackInvoker::report_primitive_instance_field(oop obj,
2414 jint index,
2415 address value,
2416 char type) {
2417 return report_primitive_field(JVMTI_HEAP_REFERENCE_FIELD,
2418 obj,
2419 index,
2420 value,
2421 type);
2422 }
2423
2424 // static field
2425 inline bool CallbackInvoker::report_primitive_static_field(oop obj,
2426 jint index,
2427 address value,
2428 char type) {
2429 return report_primitive_field(JVMTI_HEAP_REFERENCE_STATIC_FIELD,
2430 obj,
2431 index,
2432 value,
2433 type);
2434 }
2435
2436 // report a JNI local (root object) to the profiler
2437 inline bool CallbackInvoker::report_jni_local_root(jlong thread_tag, jlong tid, jint depth, jmethodID m, oop obj) {
2438 if (is_basic_heap_walk()) {
2439 return invoke_basic_stack_ref_callback(JVMTI_HEAP_ROOT_JNI_LOCAL,
2440 thread_tag,
2441 depth,
2442 m,
2443 -1,
2444 obj);
2445 } else {
2446 return invoke_advanced_stack_ref_callback(JVMTI_HEAP_REFERENCE_JNI_LOCAL,
2447 thread_tag, tid,
2448 depth,
2449 m,
2450 (jlocation)-1,
2451 -1,
2452 obj);
2453 }
2454 }
2455
2456
2457 // report a local (stack reference, root object)
2458 inline bool CallbackInvoker::report_stack_ref_root(jlong thread_tag,
2459 jlong tid,
2460 jint depth,
2461 jmethodID method,
2462 jlocation bci,
2463 jint slot,
2464 oop obj) {
2465 if (is_basic_heap_walk()) {
2466 return invoke_basic_stack_ref_callback(JVMTI_HEAP_ROOT_STACK_LOCAL,
2467 thread_tag,
2468 depth,
2469 method,
2470 slot,
2471 obj);
2472 } else {
2473 return invoke_advanced_stack_ref_callback(JVMTI_HEAP_REFERENCE_STACK_LOCAL,
2474 thread_tag,
2475 tid,
2476 depth,
2477 method,
2478 bci,
2479 slot,
2480 obj);
2481 }
2482 }
2483
2484 // report an object referencing a class.
2485 inline bool CallbackInvoker::report_class_reference(oop referrer, oop referree) {
2486 if (is_basic_heap_walk()) {
2487 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS, referrer, referree, -1);
2488 } else {
2489 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CLASS, referrer, referree, -1);
2490 }
2491 }
2492
2493 // report a class referencing its class loader.
2494 inline bool CallbackInvoker::report_class_loader_reference(oop referrer, oop referree) {
2495 if (is_basic_heap_walk()) {
2496 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS_LOADER, referrer, referree, -1);
2497 } else {
2498 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CLASS_LOADER, referrer, referree, -1);
2499 }
2500 }
2501
2502 // report a class referencing its signers.
2503 inline bool CallbackInvoker::report_signers_reference(oop referrer, oop referree) {
2504 if (is_basic_heap_walk()) {
2505 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_SIGNERS, referrer, referree, -1);
2506 } else {
2507 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_SIGNERS, referrer, referree, -1);
2508 }
2509 }
2510
2511 // report a class referencing its protection domain..
2512 inline bool CallbackInvoker::report_protection_domain_reference(oop referrer, oop referree) {
2513 if (is_basic_heap_walk()) {
2514 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_PROTECTION_DOMAIN, referrer, referree, -1);
2515 } else {
2516 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_PROTECTION_DOMAIN, referrer, referree, -1);
2517 }
2518 }
2519
2520 // report a class referencing its superclass.
2521 inline bool CallbackInvoker::report_superclass_reference(oop referrer, oop referree) {
2522 if (is_basic_heap_walk()) {
2523 // Send this to be consistent with past implementation
2524 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS, referrer, referree, -1);
2525 } else {
2526 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_SUPERCLASS, referrer, referree, -1);
2527 }
2528 }
2529
2530 // report a class referencing one of its interfaces.
2531 inline bool CallbackInvoker::report_interface_reference(oop referrer, oop referree) {
2532 if (is_basic_heap_walk()) {
2533 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_INTERFACE, referrer, referree, -1);
2534 } else {
2535 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_INTERFACE, referrer, referree, -1);
2536 }
2537 }
2538
2539 // report a class referencing one of its static fields.
2540 inline bool CallbackInvoker::report_static_field_reference(oop referrer, oop referree, jint slot) {
2541 if (is_basic_heap_walk()) {
2542 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_STATIC_FIELD, referrer, referree, slot);
2543 } else {
2544 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_STATIC_FIELD, referrer, referree, slot);
2545 }
2546 }
2547
2548 // report an array referencing an element object
2549 inline bool CallbackInvoker::report_array_element_reference(oop referrer, oop referree, jint index) {
2550 if (is_basic_heap_walk()) {
2551 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_ARRAY_ELEMENT, referrer, referree, index);
2552 } else {
2553 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT, referrer, referree, index);
2554 }
2555 }
2556
2557 // report an object referencing an instance field object
2558 inline bool CallbackInvoker::report_field_reference(oop referrer, oop referree, jint slot) {
2559 if (is_basic_heap_walk()) {
2560 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_FIELD, referrer, referree, slot);
2561 } else {
2562 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_FIELD, referrer, referree, slot);
2563 }
2564 }
2565
2566 // report an array referencing an element object
2567 inline bool CallbackInvoker::report_constant_pool_reference(oop referrer, oop referree, jint index) {
2568 if (is_basic_heap_walk()) {
2569 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CONSTANT_POOL, referrer, referree, index);
2570 } else {
2571 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CONSTANT_POOL, referrer, referree, index);
2572 }
2573 }
2574
2575 // A supporting closure used to process simple roots
2576 class SimpleRootsClosure : public OopClosure {
2577 private:
2578 jvmtiHeapReferenceKind _kind;
2579 bool _continue;
2580
2581 jvmtiHeapReferenceKind root_kind() { return _kind; }
2582
2583 public:
2584 void set_kind(jvmtiHeapReferenceKind kind) {
2585 _kind = kind;
2586 _continue = true;
2587 }
2588
2589 inline bool stopped() {
2590 return !_continue;
2591 }
2592
2593 void do_oop(oop* obj_p) {
2594 // iteration has terminated
2595 if (stopped()) {
2596 return;
2597 }
2598
2599 // ignore null or deleted handles
2600 oop o = *obj_p;
2601 if (o == NULL || o == JNIHandles::deleted_handle()) {
2602 return;
2603 }
2604
2605 jvmtiHeapReferenceKind kind = root_kind();
2606
2607 // many roots are Klasses so we use the java mirror
2608 if (o->is_klass()) {
2609 klassOop k = (klassOop)o;
2610 o = Klass::cast(k)->java_mirror();
2611 if (o == NULL) {
2612 // Classes without mirrors don't correspond to real Java
2613 // classes so just ignore them.
2614 return;
2615 }
2616 } else {
2617
2618 // SystemDictionary::always_strong_oops_do reports the application
2619 // class loader as a root. We want this root to be reported as
2620 // a root kind of "OTHER" rather than "SYSTEM_CLASS".
2621 if (o->is_instance() && root_kind() == JVMTI_HEAP_REFERENCE_SYSTEM_CLASS) {
2622 kind = JVMTI_HEAP_REFERENCE_OTHER;
2623 }
2624 }
2625
2626 // some objects are ignored - in the case of simple
2627 // roots it's mostly Symbol*s that we are skipping
2628 // here.
2629 if (!ServiceUtil::visible_oop(o)) {
2630 return;
2631 }
2632
2633 // invoke the callback
2634 _continue = CallbackInvoker::report_simple_root(kind, o);
2635
2636 }
2637 virtual void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
2638 };
2639
2640 // A supporting closure used to process JNI locals
2641 class JNILocalRootsClosure : public OopClosure {
2642 private:
2643 jlong _thread_tag;
2644 jlong _tid;
2645 jint _depth;
2646 jmethodID _method;
2647 bool _continue;
2648 public:
2649 void set_context(jlong thread_tag, jlong tid, jint depth, jmethodID method) {
2650 _thread_tag = thread_tag;
2651 _tid = tid;
2652 _depth = depth;
2653 _method = method;
2654 _continue = true;
2655 }
2656
2657 inline bool stopped() {
2658 return !_continue;
2659 }
2660
2661 void do_oop(oop* obj_p) {
2662 // iteration has terminated
2663 if (stopped()) {
2664 return;
2665 }
2666
2667 // ignore null or deleted handles
2668 oop o = *obj_p;
2669 if (o == NULL || o == JNIHandles::deleted_handle()) {
2670 return;
2671 }
2672
2673 if (!ServiceUtil::visible_oop(o)) {
2674 return;
2675 }
2676
2677 // invoke the callback
2678 _continue = CallbackInvoker::report_jni_local_root(_thread_tag, _tid, _depth, _method, o);
2679 }
2680 virtual void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
2681 };
2682
2683
2684 // A VM operation to iterate over objects that are reachable from
2685 // a set of roots or an initial object.
2686 //
2687 // For VM_HeapWalkOperation the set of roots used is :-
2688 //
2689 // - All JNI global references
2690 // - All inflated monitors
2691 // - All classes loaded by the boot class loader (or all classes
2692 // in the event that class unloading is disabled)
2693 // - All java threads
2694 // - For each java thread then all locals and JNI local references
2695 // on the thread's execution stack
2696 // - All visible/explainable objects from Universes::oops_do
2697 //
2698 class VM_HeapWalkOperation: public VM_Operation {
2699 private:
2700 enum {
2701 initial_visit_stack_size = 4000
2702 };
2703
2704 bool _is_advanced_heap_walk; // indicates FollowReferences
2705 JvmtiTagMap* _tag_map;
2706 Handle _initial_object;
2707 GrowableArray<oop>* _visit_stack; // the visit stack
2708
2709 bool _collecting_heap_roots; // are we collecting roots
2710 bool _following_object_refs; // are we following object references
2711
2712 bool _reporting_primitive_fields; // optional reporting
2713 bool _reporting_primitive_array_values;
2714 bool _reporting_string_values;
2715
2716 GrowableArray<oop>* create_visit_stack() {
2717 return new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(initial_visit_stack_size, true);
2718 }
2719
2720 // accessors
2721 bool is_advanced_heap_walk() const { return _is_advanced_heap_walk; }
2722 JvmtiTagMap* tag_map() const { return _tag_map; }
2723 Handle initial_object() const { return _initial_object; }
2724
2725 bool is_following_references() const { return _following_object_refs; }
2726
2727 bool is_reporting_primitive_fields() const { return _reporting_primitive_fields; }
2728 bool is_reporting_primitive_array_values() const { return _reporting_primitive_array_values; }
2729 bool is_reporting_string_values() const { return _reporting_string_values; }
2730
2731 GrowableArray<oop>* visit_stack() const { return _visit_stack; }
2732
2733 // iterate over the various object types
2734 inline bool iterate_over_array(oop o);
2735 inline bool iterate_over_type_array(oop o);
2736 inline bool iterate_over_class(klassOop o);
2737 inline bool iterate_over_object(oop o);
2738
2739 // root collection
2740 inline bool collect_simple_roots();
2741 inline bool collect_stack_roots();
2742 inline bool collect_stack_roots(JavaThread* java_thread, JNILocalRootsClosure* blk);
2743
2744 // visit an object
2745 inline bool visit(oop o);
2746
2747 public:
2748 VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2749 Handle initial_object,
2750 BasicHeapWalkContext callbacks,
2751 const void* user_data);
2752
2753 VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2754 Handle initial_object,
2755 AdvancedHeapWalkContext callbacks,
2756 const void* user_data);
2757
2758 ~VM_HeapWalkOperation();
2759
2760 VMOp_Type type() const { return VMOp_HeapWalkOperation; }
2761 void doit();
2762 };
2763
2764
2765 VM_HeapWalkOperation::VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2766 Handle initial_object,
2767 BasicHeapWalkContext callbacks,
2768 const void* user_data) {
2769 _is_advanced_heap_walk = false;
2770 _tag_map = tag_map;
2771 _initial_object = initial_object;
2772 _following_object_refs = (callbacks.object_ref_callback() != NULL);
2773 _reporting_primitive_fields = false;
2774 _reporting_primitive_array_values = false;
2775 _reporting_string_values = false;
2776 _visit_stack = create_visit_stack();
2777
2778
2779 CallbackInvoker::initialize_for_basic_heap_walk(tag_map, _visit_stack, user_data, callbacks);
2780 }
2781
2782 VM_HeapWalkOperation::VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2783 Handle initial_object,
2784 AdvancedHeapWalkContext callbacks,
2785 const void* user_data) {
2786 _is_advanced_heap_walk = true;
2787 _tag_map = tag_map;
2788 _initial_object = initial_object;
2789 _following_object_refs = true;
2790 _reporting_primitive_fields = (callbacks.primitive_field_callback() != NULL);;
2791 _reporting_primitive_array_values = (callbacks.array_primitive_value_callback() != NULL);;
2792 _reporting_string_values = (callbacks.string_primitive_value_callback() != NULL);;
2793 _visit_stack = create_visit_stack();
2794
2795 CallbackInvoker::initialize_for_advanced_heap_walk(tag_map, _visit_stack, user_data, callbacks);
2796 }
2797
2798 VM_HeapWalkOperation::~VM_HeapWalkOperation() {
2799 if (_following_object_refs) {
2800 assert(_visit_stack != NULL, "checking");
2801 delete _visit_stack;
2802 _visit_stack = NULL;
2803 }
2804 }
2805
2806 // an array references its class and has a reference to
2807 // each element in the array
2808 inline bool VM_HeapWalkOperation::iterate_over_array(oop o) {
2809 objArrayOop array = objArrayOop(o);
2810 if (array->klass() == Universe::systemObjArrayKlassObj()) {
2811 // filtered out
2812 return true;
2813 }
2814
2815 // array reference to its class
2816 oop mirror = objArrayKlass::cast(array->klass())->java_mirror();
2817 if (!CallbackInvoker::report_class_reference(o, mirror)) {
2818 return false;
2819 }
2820
2821 // iterate over the array and report each reference to a
2822 // non-null element
2823 for (int index=0; index<array->length(); index++) {
2824 oop elem = array->obj_at(index);
2825 if (elem == NULL) {
2826 continue;
2827 }
2828
2829 // report the array reference o[index] = elem
2830 if (!CallbackInvoker::report_array_element_reference(o, elem, index)) {
2831 return false;
2832 }
2833 }
2834 return true;
2835 }
2836
2837 // a type array references its class
2838 inline bool VM_HeapWalkOperation::iterate_over_type_array(oop o) {
2839 klassOop k = o->klass();
2840 oop mirror = Klass::cast(k)->java_mirror();
2841 if (!CallbackInvoker::report_class_reference(o, mirror)) {
2842 return false;
2843 }
2844
2845 // report the array contents if required
2846 if (is_reporting_primitive_array_values()) {
2847 if (!CallbackInvoker::report_primitive_array_values(o)) {
2848 return false;
2849 }
2850 }
2851 return true;
2852 }
2853
2854 // verify that a static oop field is in range
2855 static inline bool verify_static_oop(instanceKlass* ik,
2856 oop mirror, int offset) {
2857 address obj_p = (address)mirror + offset;
2858 address start = (address)instanceMirrorKlass::start_of_static_fields(mirror);
2859 address end = start + (java_lang_Class::static_oop_field_count(mirror) * heapOopSize);
2860 assert(end >= start, "sanity check");
2861
2862 if (obj_p >= start && obj_p < end) {
2863 return true;
2864 } else {
2865 return false;
2866 }
2867 }
2868
2869 // a class references its super class, interfaces, class loader, ...
2870 // and finally its static fields
2871 inline bool VM_HeapWalkOperation::iterate_over_class(klassOop k) {
2872 int i;
2873 Klass* klass = klassOop(k)->klass_part();
2874
2875 if (klass->oop_is_instance()) {
2876 instanceKlass* ik = instanceKlass::cast(k);
2877
2878 // ignore the class if it's has been initialized yet
2879 if (!ik->is_linked()) {
2880 return true;
2881 }
2882
2883 // get the java mirror
2884 oop mirror = klass->java_mirror();
2885
2886 // super (only if something more interesting than java.lang.Object)
2887 klassOop java_super = ik->java_super();
2888 if (java_super != NULL && java_super != SystemDictionary::Object_klass()) {
2889 oop super = Klass::cast(java_super)->java_mirror();
2890 if (!CallbackInvoker::report_superclass_reference(mirror, super)) {
2891 return false;
2892 }
2893 }
2894
2895 // class loader
2896 oop cl = ik->class_loader();
2897 if (cl != NULL) {
2898 if (!CallbackInvoker::report_class_loader_reference(mirror, cl)) {
2899 return false;
2900 }
2901 }
2902
2903 // protection domain
2904 oop pd = ik->protection_domain();
2905 if (pd != NULL) {
2906 if (!CallbackInvoker::report_protection_domain_reference(mirror, pd)) {
2907 return false;
2908 }
2909 }
2910
2911 // signers
2912 oop signers = ik->signers();
2913 if (signers != NULL) {
2914 if (!CallbackInvoker::report_signers_reference(mirror, signers)) {
2915 return false;
2916 }
2917 }
2918
2919 // references from the constant pool
2920 {
2921 const constantPoolOop pool = ik->constants();
2922 for (int i = 1; i < pool->length(); i++) {
2923 constantTag tag = pool->tag_at(i).value();
2924 if (tag.is_string() || tag.is_klass()) {
2925 oop entry;
2926 if (tag.is_string()) {
2927 entry = pool->resolved_string_at(i);
2928 assert(java_lang_String::is_instance(entry), "must be string");
2929 } else {
2930 entry = Klass::cast(pool->resolved_klass_at(i))->java_mirror();
2931 }
2932 if (!CallbackInvoker::report_constant_pool_reference(mirror, entry, (jint)i)) {
2933 return false;
2934 }
2935 }
2936 }
2937 }
2938
2939 // interfaces
2940 // (These will already have been reported as references from the constant pool
2941 // but are specified by IterateOverReachableObjects and must be reported).
2942 objArrayOop interfaces = ik->local_interfaces();
2943 for (i = 0; i < interfaces->length(); i++) {
2944 oop interf = Klass::cast((klassOop)interfaces->obj_at(i))->java_mirror();
2945 if (interf == NULL) {
2946 continue;
2947 }
2948 if (!CallbackInvoker::report_interface_reference(mirror, interf)) {
2949 return false;
2950 }
2951 }
2952
2953 // iterate over the static fields
2954
2955 ClassFieldMap* field_map = ClassFieldMap::create_map_of_static_fields(k);
2956 for (i=0; i<field_map->field_count(); i++) {
2957 ClassFieldDescriptor* field = field_map->field_at(i);
2958 char type = field->field_type();
2959 if (!is_primitive_field_type(type)) {
2960 oop fld_o = mirror->obj_field(field->field_offset());
2961 assert(verify_static_oop(ik, mirror, field->field_offset()), "sanity check");
2962 if (fld_o != NULL) {
2963 int slot = field->field_index();
2964 if (!CallbackInvoker::report_static_field_reference(mirror, fld_o, slot)) {
2965 delete field_map;
2966 return false;
2967 }
2968 }
2969 } else {
2970 if (is_reporting_primitive_fields()) {
2971 address addr = (address)mirror + field->field_offset();
2972 int slot = field->field_index();
2973 if (!CallbackInvoker::report_primitive_static_field(mirror, slot, addr, type)) {
2974 delete field_map;
2975 return false;
2976 }
2977 }
2978 }
2979 }
2980 delete field_map;
2981
2982 return true;
2983 }
2984
2985 return true;
2986 }
2987
2988 // an object references a class and its instance fields
2989 // (static fields are ignored here as we report these as
2990 // references from the class).
2991 inline bool VM_HeapWalkOperation::iterate_over_object(oop o) {
2992 // reference to the class
2993 if (!CallbackInvoker::report_class_reference(o, Klass::cast(o->klass())->java_mirror())) {
2994 return false;
2995 }
2996
2997 // iterate over instance fields
2998 ClassFieldMap* field_map = JvmtiCachedClassFieldMap::get_map_of_instance_fields(o);
2999 for (int i=0; i<field_map->field_count(); i++) {
3000 ClassFieldDescriptor* field = field_map->field_at(i);
3001 char type = field->field_type();
3002 if (!is_primitive_field_type(type)) {
3003 oop fld_o = o->obj_field(field->field_offset());
3004 // ignore any objects that aren't visible to profiler
3005 if (fld_o != NULL && ServiceUtil::visible_oop(fld_o)) {
3006 // reflection code may have a reference to a klassOop.
3007 // - see sun.reflect.UnsafeStaticFieldAccessorImpl and sun.misc.Unsafe
3008 if (fld_o->is_klass()) {
3009 klassOop k = (klassOop)fld_o;
3010 fld_o = Klass::cast(k)->java_mirror();
3011 }
3012 int slot = field->field_index();
3013 if (!CallbackInvoker::report_field_reference(o, fld_o, slot)) {
3014 return false;
3015 }
3016 }
3017 } else {
3018 if (is_reporting_primitive_fields()) {
3019 // primitive instance field
3020 address addr = (address)o + field->field_offset();
3021 int slot = field->field_index();
3022 if (!CallbackInvoker::report_primitive_instance_field(o, slot, addr, type)) {
3023 return false;
3024 }
3025 }
3026 }
3027 }
3028
3029 // if the object is a java.lang.String
3030 if (is_reporting_string_values() &&
3031 o->klass() == SystemDictionary::String_klass()) {
3032 if (!CallbackInvoker::report_string_value(o)) {
3033 return false;
3034 }
3035 }
3036 return true;
3037 }
3038
3039
3040 // Collects all simple (non-stack) roots except for threads;
3041 // threads are handled in collect_stack_roots() as an optimization.
3042 // if there's a heap root callback provided then the callback is
3043 // invoked for each simple root.
3044 // if an object reference callback is provided then all simple
3045 // roots are pushed onto the marking stack so that they can be
3046 // processed later
3047 //
3048 inline bool VM_HeapWalkOperation::collect_simple_roots() {
3049 SimpleRootsClosure blk;
3050
3051 // JNI globals
3052 blk.set_kind(JVMTI_HEAP_REFERENCE_JNI_GLOBAL);
3053 JNIHandles::oops_do(&blk);
3054 if (blk.stopped()) {
3055 return false;
3056 }
3057
3058 // Preloaded classes and loader from the system dictionary
3059 blk.set_kind(JVMTI_HEAP_REFERENCE_SYSTEM_CLASS);
3060 SystemDictionary::always_strong_oops_do(&blk);
3061 if (blk.stopped()) {
3062 return false;
3063 }
3064
3065 // Inflated monitors
3066 blk.set_kind(JVMTI_HEAP_REFERENCE_MONITOR);
3067 ObjectSynchronizer::oops_do(&blk);
3068 if (blk.stopped()) {
3069 return false;
3070 }
3071
3072 // threads are now handled in collect_stack_roots()
3073
3074 // Other kinds of roots maintained by HotSpot
3075 // Many of these won't be visible but others (such as instances of important
3076 // exceptions) will be visible.
3077 blk.set_kind(JVMTI_HEAP_REFERENCE_OTHER);
3078 Universe::oops_do(&blk);
3079
3080 // If there are any non-perm roots in the code cache, visit them.
3081 blk.set_kind(JVMTI_HEAP_REFERENCE_OTHER);
3082 CodeBlobToOopClosure look_in_blobs(&blk, false);
3083 CodeCache::scavenge_root_nmethods_do(&look_in_blobs);
3084
3085 return true;
3086 }
3087
3088 // Walk the stack of a given thread and find all references (locals
3089 // and JNI calls) and report these as stack references
3090 inline bool VM_HeapWalkOperation::collect_stack_roots(JavaThread* java_thread,
3091 JNILocalRootsClosure* blk)
3092 {
3093 oop threadObj = java_thread->threadObj();
3094 assert(threadObj != NULL, "sanity check");
3095
3096 // only need to get the thread's tag once per thread
3097 jlong thread_tag = tag_for(_tag_map, threadObj);
3098
3099 // also need the thread id
3100 jlong tid = java_lang_Thread::thread_id(threadObj);
3101
3102
3103 if (java_thread->has_last_Java_frame()) {
3104
3105 // vframes are resource allocated
3106 Thread* current_thread = Thread::current();
3107 ResourceMark rm(current_thread);
3108 HandleMark hm(current_thread);
3109
3110 RegisterMap reg_map(java_thread);
3111 frame f = java_thread->last_frame();
3112 vframe* vf = vframe::new_vframe(&f, ®_map, java_thread);
3113
3114 bool is_top_frame = true;
3115 int depth = 0;
3116 frame* last_entry_frame = NULL;
3117
3118 while (vf != NULL) {
3119 if (vf->is_java_frame()) {
3120
3121 // java frame (interpreted, compiled, ...)
3122 javaVFrame *jvf = javaVFrame::cast(vf);
3123
3124 // the jmethodID
3125 jmethodID method = jvf->method()->jmethod_id();
3126
3127 if (!(jvf->method()->is_native())) {
3128 jlocation bci = (jlocation)jvf->bci();
3129 StackValueCollection* locals = jvf->locals();
3130 for (int slot=0; slot<locals->size(); slot++) {
3131 if (locals->at(slot)->type() == T_OBJECT) {
3132 oop o = locals->obj_at(slot)();
3133 if (o == NULL) {
3134 continue;
3135 }
3136
3137 // stack reference
3138 if (!CallbackInvoker::report_stack_ref_root(thread_tag, tid, depth, method,
3139 bci, slot, o)) {
3140 return false;
3141 }
3142 }
3143 }
3144 } else {
3145 blk->set_context(thread_tag, tid, depth, method);
3146 if (is_top_frame) {
3147 // JNI locals for the top frame.
3148 java_thread->active_handles()->oops_do(blk);
3149 } else {
3150 if (last_entry_frame != NULL) {
3151 // JNI locals for the entry frame
3152 assert(last_entry_frame->is_entry_frame(), "checking");
3153 last_entry_frame->entry_frame_call_wrapper()->handles()->oops_do(blk);
3154 }
3155 }
3156 }
3157 last_entry_frame = NULL;
3158 depth++;
3159 } else {
3160 // externalVFrame - for an entry frame then we report the JNI locals
3161 // when we find the corresponding javaVFrame
3162 frame* fr = vf->frame_pointer();
3163 assert(fr != NULL, "sanity check");
3164 if (fr->is_entry_frame()) {
3165 last_entry_frame = fr;
3166 }
3167 }
3168
3169 vf = vf->sender();
3170 is_top_frame = false;
3171 }
3172 } else {
3173 // no last java frame but there may be JNI locals
3174 blk->set_context(thread_tag, tid, 0, (jmethodID)NULL);
3175 java_thread->active_handles()->oops_do(blk);
3176 }
3177 return true;
3178 }
3179
3180
3181 // Collects the simple roots for all threads and collects all
3182 // stack roots - for each thread it walks the execution
3183 // stack to find all references and local JNI refs.
3184 inline bool VM_HeapWalkOperation::collect_stack_roots() {
3185 JNILocalRootsClosure blk;
3186 for (JavaThread* thread = Threads::first(); thread != NULL ; thread = thread->next()) {
3187 oop threadObj = thread->threadObj();
3188 if (threadObj != NULL && !thread->is_exiting() && !thread->is_hidden_from_external_view()) {
3189 // Collect the simple root for this thread before we
3190 // collect its stack roots
3191 if (!CallbackInvoker::report_simple_root(JVMTI_HEAP_REFERENCE_THREAD,
3192 threadObj)) {
3193 return false;
3194 }
3195 if (!collect_stack_roots(thread, &blk)) {
3196 return false;
3197 }
3198 }
3199 }
3200 return true;
3201 }
3202
3203 // visit an object
3204 // first mark the object as visited
3205 // second get all the outbound references from this object (in other words, all
3206 // the objects referenced by this object).
3207 //
3208 bool VM_HeapWalkOperation::visit(oop o) {
3209 // mark object as visited
3210 assert(!ObjectMarker::visited(o), "can't visit same object more than once");
3211 ObjectMarker::mark(o);
3212
3213 // instance
3214 if (o->is_instance()) {
3215 if (o->klass() == SystemDictionary::Class_klass()) {
3216 o = klassOop_if_java_lang_Class(o);
3217 if (o->is_klass()) {
3218 // a java.lang.Class
3219 return iterate_over_class(klassOop(o));
3220 }
3221 } else {
3222 return iterate_over_object(o);
3223 }
3224 }
3225
3226 // object array
3227 if (o->is_objArray()) {
3228 return iterate_over_array(o);
3229 }
3230
3231 // type array
3232 if (o->is_typeArray()) {
3233 return iterate_over_type_array(o);
3234 }
3235
3236 return true;
3237 }
3238
3239 void VM_HeapWalkOperation::doit() {
3240 ResourceMark rm;
3241 ObjectMarkerController marker;
3242 ClassFieldMapCacheMark cm;
3243
3244 assert(visit_stack()->is_empty(), "visit stack must be empty");
3245
3246 // the heap walk starts with an initial object or the heap roots
3247 if (initial_object().is_null()) {
3248 // If either collect_stack_roots() or collect_simple_roots()
3249 // returns false at this point, then there are no mark bits
3250 // to reset.
3251 ObjectMarker::set_needs_reset(false);
3252
3253 // Calling collect_stack_roots() before collect_simple_roots()
3254 // can result in a big performance boost for an agent that is
3255 // focused on analyzing references in the thread stacks.
3256 if (!collect_stack_roots()) return;
3257
3258 if (!collect_simple_roots()) return;
3259
3260 // no early return so enable heap traversal to reset the mark bits
3261 ObjectMarker::set_needs_reset(true);
3262 } else {
3263 visit_stack()->push(initial_object()());
3264 }
3265
3266 // object references required
3267 if (is_following_references()) {
3268
3269 // visit each object until all reachable objects have been
3270 // visited or the callback asked to terminate the iteration.
3271 while (!visit_stack()->is_empty()) {
3272 oop o = visit_stack()->pop();
3273 if (!ObjectMarker::visited(o)) {
3274 if (!visit(o)) {
3275 break;
3276 }
3277 }
3278 }
3279 }
3280 }
3281
3282 // iterate over all objects that are reachable from a set of roots
3283 void JvmtiTagMap::iterate_over_reachable_objects(jvmtiHeapRootCallback heap_root_callback,
3284 jvmtiStackReferenceCallback stack_ref_callback,
3285 jvmtiObjectReferenceCallback object_ref_callback,
3286 const void* user_data) {
3287 MutexLocker ml(Heap_lock);
3288 BasicHeapWalkContext context(heap_root_callback, stack_ref_callback, object_ref_callback);
3289 VM_HeapWalkOperation op(this, Handle(), context, user_data);
3290 VMThread::execute(&op);
3291 }
3292
3293 // iterate over all objects that are reachable from a given object
3294 void JvmtiTagMap::iterate_over_objects_reachable_from_object(jobject object,
3295 jvmtiObjectReferenceCallback object_ref_callback,
3296 const void* user_data) {
3297 oop obj = JNIHandles::resolve(object);
3298 Handle initial_object(Thread::current(), obj);
3299
3300 MutexLocker ml(Heap_lock);
3301 BasicHeapWalkContext context(NULL, NULL, object_ref_callback);
3302 VM_HeapWalkOperation op(this, initial_object, context, user_data);
3303 VMThread::execute(&op);
3304 }
3305
3306 // follow references from an initial object or the GC roots
3307 void JvmtiTagMap::follow_references(jint heap_filter,
3308 KlassHandle klass,
3309 jobject object,
3310 const jvmtiHeapCallbacks* callbacks,
3311 const void* user_data)
3312 {
3313 oop obj = JNIHandles::resolve(object);
3314 Handle initial_object(Thread::current(), obj);
3315
3316 MutexLocker ml(Heap_lock);
3317 AdvancedHeapWalkContext context(heap_filter, klass, callbacks);
3318 VM_HeapWalkOperation op(this, initial_object, context, user_data);
3319 VMThread::execute(&op);
3320 }
3321
3322
3323 void JvmtiTagMap::weak_oops_do(BoolObjectClosure* is_alive, OopClosure* f) {
3324 // No locks during VM bring-up (0 threads) and no safepoints after main
3325 // thread creation and before VMThread creation (1 thread); initial GC
3326 // verification can happen in that window which gets to here.
3327 assert(Threads::number_of_threads() <= 1 ||
3328 SafepointSynchronize::is_at_safepoint(),
3329 "must be executed at a safepoint");
3330 if (JvmtiEnv::environments_might_exist()) {
3331 JvmtiEnvIterator it;
3332 for (JvmtiEnvBase* env = it.first(); env != NULL; env = it.next(env)) {
3333 JvmtiTagMap* tag_map = env->tag_map();
3334 if (tag_map != NULL && !tag_map->is_empty()) {
3335 tag_map->do_weak_oops(is_alive, f);
3336 }
3337 }
3338 }
3339 }
3340
3341 void JvmtiTagMap::do_weak_oops(BoolObjectClosure* is_alive, OopClosure* f) {
3342
3343 // does this environment have the OBJECT_FREE event enabled
3344 bool post_object_free = env()->is_enabled(JVMTI_EVENT_OBJECT_FREE);
3345
3346 // counters used for trace message
3347 int freed = 0;
3348 int moved = 0;
3349
3350 JvmtiTagHashmap* hashmap = this->hashmap();
3351
3352 // reenable sizing (if disabled)
3353 hashmap->set_resizing_enabled(true);
3354
3355 // if the hashmap is empty then we can skip it
3356 if (hashmap->_entry_count == 0) {
3357 return;
3358 }
3359
3360 // now iterate through each entry in the table
3361
3362 JvmtiTagHashmapEntry** table = hashmap->table();
3363 int size = hashmap->size();
3364
3365 JvmtiTagHashmapEntry* delayed_add = NULL;
3366
3367 for (int pos = 0; pos < size; ++pos) {
3368 JvmtiTagHashmapEntry* entry = table[pos];
3369 JvmtiTagHashmapEntry* prev = NULL;
3370
3371 while (entry != NULL) {
3372 JvmtiTagHashmapEntry* next = entry->next();
3373
3374 oop* obj = entry->object_addr();
3375
3376 // has object been GC'ed
3377 if (!is_alive->do_object_b(entry->object())) {
3378 // grab the tag
3379 jlong tag = entry->tag();
3380 guarantee(tag != 0, "checking");
3381
3382 // remove GC'ed entry from hashmap and return the
3383 // entry to the free list
3384 hashmap->remove(prev, pos, entry);
3385 destroy_entry(entry);
3386
3387 // post the event to the profiler
3388 if (post_object_free) {
3389 JvmtiExport::post_object_free(env(), tag);
3390 }
3391
3392 ++freed;
3393 } else {
3394 f->do_oop(entry->object_addr());
3395 oop new_oop = entry->object();
3396
3397 // if the object has moved then re-hash it and move its
3398 // entry to its new location.
3399 unsigned int new_pos = JvmtiTagHashmap::hash(new_oop, size);
3400 if (new_pos != (unsigned int)pos) {
3401 if (prev == NULL) {
3402 table[pos] = next;
3403 } else {
3404 prev->set_next(next);
3405 }
3406 if (new_pos < (unsigned int)pos) {
3407 entry->set_next(table[new_pos]);
3408 table[new_pos] = entry;
3409 } else {
3410 // Delay adding this entry to it's new position as we'd end up
3411 // hitting it again during this iteration.
3412 entry->set_next(delayed_add);
3413 delayed_add = entry;
3414 }
3415 moved++;
3416 } else {
3417 // object didn't move
3418 prev = entry;
3419 }
3420 }
3421
3422 entry = next;
3423 }
3424 }
3425
3426 // Re-add all the entries which were kept aside
3427 while (delayed_add != NULL) {
3428 JvmtiTagHashmapEntry* next = delayed_add->next();
3429 unsigned int pos = JvmtiTagHashmap::hash(delayed_add->object(), size);
3430 delayed_add->set_next(table[pos]);
3431 table[pos] = delayed_add;
3432 delayed_add = next;
3433 }
3434
3435 // stats
3436 if (TraceJVMTIObjectTagging) {
3437 int post_total = hashmap->_entry_count;
3438 int pre_total = post_total + freed;
3439
3440 tty->print_cr("(%d->%d, %d freed, %d total moves)",
3441 pre_total, post_total, freed, moved);
3442 }
3443 }