1 /*
2 * Copyright (c) 2003, 2019, 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/classLoaderDataGraph.hpp"
27 #include "classfile/javaClasses.inline.hpp"
28 #include "classfile/symbolTable.hpp"
29 #include "classfile/systemDictionary.hpp"
30 #include "classfile/vmSymbols.hpp"
31 #include "jvmtifiles/jvmtiEnv.hpp"
32 #include "logging/log.hpp"
33 #include "memory/allocation.inline.hpp"
34 #include "memory/resourceArea.hpp"
35 #include "memory/universe.hpp"
36 #include "oops/access.inline.hpp"
37 #include "oops/arrayOop.inline.hpp"
38 #include "oops/constantPool.inline.hpp"
39 #include "oops/instanceMirrorKlass.hpp"
40 #include "oops/objArrayKlass.hpp"
41 #include "oops/objArrayOop.inline.hpp"
42 #include "oops/oop.inline.hpp"
43 #include "oops/typeArrayOop.inline.hpp"
44 #include "prims/jvmtiEventController.hpp"
45 #include "prims/jvmtiEventController.inline.hpp"
46 #include "prims/jvmtiExport.hpp"
47 #include "prims/jvmtiImpl.hpp"
48 #include "prims/jvmtiTagMap.hpp"
49 #include "runtime/biasedLocking.hpp"
50 #include "runtime/deoptimization.hpp"
51 #include "runtime/frame.inline.hpp"
52 #include "runtime/handles.inline.hpp"
53 #include "runtime/javaCalls.hpp"
54 #include "runtime/jniHandles.inline.hpp"
55 #include "runtime/mutex.hpp"
56 #include "runtime/mutexLocker.hpp"
57 #include "runtime/reflectionUtils.hpp"
58 #include "runtime/thread.inline.hpp"
59 #include "runtime/threadSMR.hpp"
60 #include "runtime/vframe.hpp"
61 #include "runtime/vmThread.hpp"
62 #include "runtime/vmOperations.hpp"
63 #include "utilities/macros.hpp"
64 #if INCLUDE_ZGC
65 #include "gc/z/zGlobals.hpp"
66 #endif
67
68 // JvmtiTagHashmapEntry
69 //
70 // Each entry encapsulates a reference to the tagged object
71 // and the tag value. In addition an entry includes a next pointer which
72 // is used to chain entries together.
73
74 class JvmtiTagHashmapEntry : public CHeapObj<mtInternal> {
75 private:
76 friend class JvmtiTagMap;
77
78 oop _object; // tagged object
79 jlong _tag; // the tag
80 JvmtiTagHashmapEntry* _next; // next on the list
81
82 inline void init(oop object, jlong tag) {
83 _object = object;
84 _tag = tag;
85 _next = NULL;
86 }
87
88 // constructor
89 JvmtiTagHashmapEntry(oop object, jlong tag) { init(object, tag); }
90
91 public:
92
93 // accessor methods
94 inline oop* object_addr() { return &_object; }
95 inline oop object() { return NativeAccess<ON_PHANTOM_OOP_REF>::oop_load(object_addr()); }
96 // Peek at the object without keeping it alive. The returned object must be
97 // kept alive using a normal access if it leaks out of a thread transition from VM.
98 inline oop object_peek() {
99 return NativeAccess<ON_PHANTOM_OOP_REF | AS_NO_KEEPALIVE>::oop_load(object_addr());
100 }
101 inline jlong tag() const { return _tag; }
102
103 inline void set_tag(jlong tag) {
104 assert(tag != 0, "can't be zero");
105 _tag = tag;
106 }
107
108 inline bool equals(oop object) {
109 return oopDesc::equals(object, object_peek());
110 }
111
112 inline JvmtiTagHashmapEntry* next() const { return _next; }
113 inline void set_next(JvmtiTagHashmapEntry* next) { _next = next; }
114 };
115
116
117 // JvmtiTagHashmap
118 //
119 // A hashmap is essentially a table of pointers to entries. Entries
120 // are hashed to a location, or position in the table, and then
121 // chained from that location. The "key" for hashing is address of
122 // the object, or oop. The "value" is the tag value.
123 //
124 // A hashmap maintains a count of the number entries in the hashmap
125 // and resizes if the number of entries exceeds a given threshold.
126 // The threshold is specified as a percentage of the size - for
127 // example a threshold of 0.75 will trigger the hashmap to resize
128 // if the number of entries is >75% of table size.
129 //
130 // A hashmap provides functions for adding, removing, and finding
131 // entries. It also provides a function to iterate over all entries
132 // in the hashmap.
133
134 class JvmtiTagHashmap : public CHeapObj<mtInternal> {
135 private:
136 friend class JvmtiTagMap;
137
138 enum {
139 small_trace_threshold = 10000, // threshold for tracing
140 medium_trace_threshold = 100000,
141 large_trace_threshold = 1000000,
142 initial_trace_threshold = small_trace_threshold
143 };
144
145 static int _sizes[]; // array of possible hashmap sizes
146 int _size; // actual size of the table
147 int _size_index; // index into size table
148
149 int _entry_count; // number of entries in the hashmap
150
151 float _load_factor; // load factor as a % of the size
152 int _resize_threshold; // computed threshold to trigger resizing.
153 bool _resizing_enabled; // indicates if hashmap can resize
154
155 int _trace_threshold; // threshold for trace messages
156
157 JvmtiTagHashmapEntry** _table; // the table of entries.
158
159 // private accessors
160 int resize_threshold() const { return _resize_threshold; }
161 int trace_threshold() const { return _trace_threshold; }
162
163 // initialize the hashmap
164 void init(int size_index=0, float load_factor=4.0f) {
165 int initial_size = _sizes[size_index];
166 _size_index = size_index;
167 _size = initial_size;
168 _entry_count = 0;
169 _trace_threshold = initial_trace_threshold;
170 _load_factor = load_factor;
171 _resize_threshold = (int)(_load_factor * _size);
172 _resizing_enabled = true;
173 size_t s = initial_size * sizeof(JvmtiTagHashmapEntry*);
174 _table = (JvmtiTagHashmapEntry**)os::malloc(s, mtInternal);
175 if (_table == NULL) {
176 vm_exit_out_of_memory(s, OOM_MALLOC_ERROR,
177 "unable to allocate initial hashtable for jvmti object tags");
178 }
179 for (int i=0; i<initial_size; i++) {
180 _table[i] = NULL;
181 }
182 }
183
184 // hash a given key (oop) with the specified size
185 static unsigned int hash(oop key, int size) {
186 const oop obj = Access<>::resolve(key);
187 const unsigned int hash = Universe::heap()->hash_oop(obj);
188 return hash % size;
189 }
190
191 // hash a given key (oop)
192 unsigned int hash(oop key) {
193 return hash(key, _size);
194 }
195
196 // resize the hashmap - allocates a large table and re-hashes
197 // all entries into the new table.
198 void resize() {
199 int new_size_index = _size_index+1;
200 int new_size = _sizes[new_size_index];
201 if (new_size < 0) {
202 // hashmap already at maximum capacity
203 return;
204 }
205
206 // allocate new table
207 size_t s = new_size * sizeof(JvmtiTagHashmapEntry*);
208 JvmtiTagHashmapEntry** new_table = (JvmtiTagHashmapEntry**)os::malloc(s, mtInternal);
209 if (new_table == NULL) {
210 warning("unable to allocate larger hashtable for jvmti object tags");
211 set_resizing_enabled(false);
212 return;
213 }
214
215 // initialize new table
216 int i;
217 for (i=0; i<new_size; i++) {
218 new_table[i] = NULL;
219 }
220
221 // rehash all entries into the new table
222 for (i=0; i<_size; i++) {
223 JvmtiTagHashmapEntry* entry = _table[i];
224 while (entry != NULL) {
225 JvmtiTagHashmapEntry* next = entry->next();
226 oop key = entry->object_peek();
227 assert(key != NULL, "jni weak reference cleared!!");
228 unsigned int h = hash(key, new_size);
229 JvmtiTagHashmapEntry* anchor = new_table[h];
230 if (anchor == NULL) {
231 new_table[h] = entry;
232 entry->set_next(NULL);
233 } else {
234 entry->set_next(anchor);
235 new_table[h] = entry;
236 }
237 entry = next;
238 }
239 }
240
241 // free old table and update settings.
242 os::free((void*)_table);
243 _table = new_table;
244 _size_index = new_size_index;
245 _size = new_size;
246
247 // compute new resize threshold
248 _resize_threshold = (int)(_load_factor * _size);
249 }
250
251
252 // internal remove function - remove an entry at a given position in the
253 // table.
254 inline void remove(JvmtiTagHashmapEntry* prev, int pos, JvmtiTagHashmapEntry* entry) {
255 assert(pos >= 0 && pos < _size, "out of range");
256 if (prev == NULL) {
257 _table[pos] = entry->next();
258 } else {
259 prev->set_next(entry->next());
260 }
261 assert(_entry_count > 0, "checking");
262 _entry_count--;
263 }
264
265 // resizing switch
266 bool is_resizing_enabled() const { return _resizing_enabled; }
267 void set_resizing_enabled(bool enable) { _resizing_enabled = enable; }
268
269 // debugging
270 void print_memory_usage();
271 void compute_next_trace_threshold();
272
273 public:
274
275 // create a JvmtiTagHashmap of a preferred size and optionally a load factor.
276 // The preferred size is rounded down to an actual size.
277 JvmtiTagHashmap(int size, float load_factor=0.0f) {
278 int i=0;
279 while (_sizes[i] < size) {
280 if (_sizes[i] < 0) {
281 assert(i > 0, "sanity check");
282 i--;
283 break;
284 }
285 i++;
286 }
287
288 // if a load factor is specified then use it, otherwise use default
289 if (load_factor > 0.01f) {
290 init(i, load_factor);
291 } else {
292 init(i);
293 }
294 }
295
296 // create a JvmtiTagHashmap with default settings
297 JvmtiTagHashmap() {
298 init();
299 }
300
301 // release table when JvmtiTagHashmap destroyed
302 ~JvmtiTagHashmap() {
303 if (_table != NULL) {
304 os::free((void*)_table);
305 _table = NULL;
306 }
307 }
308
309 // accessors
310 int size() const { return _size; }
311 JvmtiTagHashmapEntry** table() const { return _table; }
312 int entry_count() const { return _entry_count; }
313
314 // find an entry in the hashmap, returns NULL if not found.
315 inline JvmtiTagHashmapEntry* find(oop key) {
316 unsigned int h = hash(key);
317 JvmtiTagHashmapEntry* entry = _table[h];
318 while (entry != NULL) {
319 if (entry->equals(key)) {
320 return entry;
321 }
322 entry = entry->next();
323 }
324 return NULL;
325 }
326
327
328 // add a new entry to hashmap
329 inline void add(oop key, JvmtiTagHashmapEntry* entry) {
330 assert(key != NULL, "checking");
331 assert(find(key) == NULL, "duplicate detected");
332 unsigned int h = hash(key);
333 JvmtiTagHashmapEntry* anchor = _table[h];
334 if (anchor == NULL) {
335 _table[h] = entry;
336 entry->set_next(NULL);
337 } else {
338 entry->set_next(anchor);
339 _table[h] = entry;
340 }
341
342 _entry_count++;
343 if (log_is_enabled(Debug, jvmti, objecttagging) && entry_count() >= trace_threshold()) {
344 print_memory_usage();
345 compute_next_trace_threshold();
346 }
347
348 // if the number of entries exceed the threshold then resize
349 if (entry_count() > resize_threshold() && is_resizing_enabled()) {
350 resize();
351 }
352 }
353
354 // remove an entry with the given key.
355 inline JvmtiTagHashmapEntry* remove(oop key) {
356 unsigned int h = hash(key);
357 JvmtiTagHashmapEntry* entry = _table[h];
358 JvmtiTagHashmapEntry* prev = NULL;
359 while (entry != NULL) {
360 if (entry->equals(key)) {
361 break;
362 }
363 prev = entry;
364 entry = entry->next();
365 }
366 if (entry != NULL) {
367 remove(prev, h, entry);
368 }
369 return entry;
370 }
371
372 // iterate over all entries in the hashmap
373 void entry_iterate(JvmtiTagHashmapEntryClosure* closure);
374 };
375
376 // possible hashmap sizes - odd primes that roughly double in size.
377 // To avoid excessive resizing the odd primes from 4801-76831 and
378 // 76831-307261 have been removed. The list must be terminated by -1.
379 int JvmtiTagHashmap::_sizes[] = { 4801, 76831, 307261, 614563, 1228891,
380 2457733, 4915219, 9830479, 19660831, 39321619, 78643219, -1 };
381
382
383 // A supporting class for iterating over all entries in Hashmap
384 class JvmtiTagHashmapEntryClosure {
385 public:
386 virtual void do_entry(JvmtiTagHashmapEntry* entry) = 0;
387 };
388
389
390 // iterate over all entries in the hashmap
391 void JvmtiTagHashmap::entry_iterate(JvmtiTagHashmapEntryClosure* closure) {
392 for (int i=0; i<_size; i++) {
393 JvmtiTagHashmapEntry* entry = _table[i];
394 JvmtiTagHashmapEntry* prev = NULL;
395 while (entry != NULL) {
396 // obtain the next entry before invoking do_entry - this is
397 // necessary because do_entry may remove the entry from the
398 // hashmap.
399 JvmtiTagHashmapEntry* next = entry->next();
400 closure->do_entry(entry);
401 entry = next;
402 }
403 }
404 }
405
406 // debugging
407 void JvmtiTagHashmap::print_memory_usage() {
408 intptr_t p = (intptr_t)this;
409 tty->print("[JvmtiTagHashmap @ " INTPTR_FORMAT, p);
410
411 // table + entries in KB
412 int hashmap_usage = (size()*sizeof(JvmtiTagHashmapEntry*) +
413 entry_count()*sizeof(JvmtiTagHashmapEntry))/K;
414
415 int weak_globals_usage = (int)(JNIHandles::weak_global_handle_memory_usage()/K);
416 tty->print_cr(", %d entries (%d KB) <JNI weak globals: %d KB>]",
417 entry_count(), hashmap_usage, weak_globals_usage);
418 }
419
420 // compute threshold for the next trace message
421 void JvmtiTagHashmap::compute_next_trace_threshold() {
422 _trace_threshold = entry_count();
423 if (trace_threshold() < medium_trace_threshold) {
424 _trace_threshold += small_trace_threshold;
425 } else {
426 if (trace_threshold() < large_trace_threshold) {
427 _trace_threshold += medium_trace_threshold;
428 } else {
429 _trace_threshold += large_trace_threshold;
430 }
431 }
432 }
433
434 // create a JvmtiTagMap
435 JvmtiTagMap::JvmtiTagMap(JvmtiEnv* env) :
436 _env(env),
437 _lock(Mutex::nonleaf+2, "JvmtiTagMap._lock", false),
438 _free_entries(NULL),
439 _free_entries_count(0)
440 {
441 assert(JvmtiThreadState_lock->is_locked(), "sanity check");
442 assert(((JvmtiEnvBase *)env)->tag_map() == NULL, "tag map already exists for environment");
443
444 _hashmap = new JvmtiTagHashmap();
445
446 // finally add us to the environment
447 ((JvmtiEnvBase *)env)->release_set_tag_map(this);
448 }
449
450
451 // destroy a JvmtiTagMap
452 JvmtiTagMap::~JvmtiTagMap() {
453
454 // no lock acquired as we assume the enclosing environment is
455 // also being destroryed.
456 ((JvmtiEnvBase *)_env)->set_tag_map(NULL);
457
458 JvmtiTagHashmapEntry** table = _hashmap->table();
459 for (int j = 0; j < _hashmap->size(); j++) {
460 JvmtiTagHashmapEntry* entry = table[j];
461 while (entry != NULL) {
462 JvmtiTagHashmapEntry* next = entry->next();
463 delete entry;
464 entry = next;
465 }
466 }
467
468 // finally destroy the hashmap
469 delete _hashmap;
470 _hashmap = NULL;
471
472 // remove any entries on the free list
473 JvmtiTagHashmapEntry* entry = _free_entries;
474 while (entry != NULL) {
475 JvmtiTagHashmapEntry* next = entry->next();
476 delete entry;
477 entry = next;
478 }
479 _free_entries = NULL;
480 }
481
482 // create a hashmap entry
483 // - if there's an entry on the (per-environment) free list then this
484 // is returned. Otherwise an new entry is allocated.
485 JvmtiTagHashmapEntry* JvmtiTagMap::create_entry(oop ref, jlong tag) {
486 assert(Thread::current()->is_VM_thread() || is_locked(), "checking");
487 JvmtiTagHashmapEntry* entry;
488 if (_free_entries == NULL) {
489 entry = new JvmtiTagHashmapEntry(ref, tag);
490 } else {
491 assert(_free_entries_count > 0, "mismatched _free_entries_count");
492 _free_entries_count--;
493 entry = _free_entries;
494 _free_entries = entry->next();
495 entry->init(ref, tag);
496 }
497 return entry;
498 }
499
500 // destroy an entry by returning it to the free list
501 void JvmtiTagMap::destroy_entry(JvmtiTagHashmapEntry* entry) {
502 assert(SafepointSynchronize::is_at_safepoint() || is_locked(), "checking");
503 // limit the size of the free list
504 if (_free_entries_count >= max_free_entries) {
505 delete entry;
506 } else {
507 entry->set_next(_free_entries);
508 _free_entries = entry;
509 _free_entries_count++;
510 }
511 }
512
513 // returns the tag map for the given environments. If the tag map
514 // doesn't exist then it is created.
515 JvmtiTagMap* JvmtiTagMap::tag_map_for(JvmtiEnv* env) {
516 JvmtiTagMap* tag_map = ((JvmtiEnvBase*)env)->tag_map_acquire();
517 if (tag_map == NULL) {
518 MutexLocker mu(JvmtiThreadState_lock);
519 tag_map = ((JvmtiEnvBase*)env)->tag_map();
520 if (tag_map == NULL) {
521 tag_map = new JvmtiTagMap(env);
522 }
523 } else {
524 DEBUG_ONLY(Thread::current()->check_possible_safepoint());
525 }
526 return tag_map;
527 }
528
529 // iterate over all entries in the tag map.
530 void JvmtiTagMap::entry_iterate(JvmtiTagHashmapEntryClosure* closure) {
531 hashmap()->entry_iterate(closure);
532 }
533
534 // returns true if the hashmaps are empty
535 bool JvmtiTagMap::is_empty() {
536 assert(SafepointSynchronize::is_at_safepoint() || is_locked(), "checking");
537 return hashmap()->entry_count() == 0;
538 }
539
540
541 // Return the tag value for an object, or 0 if the object is
542 // not tagged
543 //
544 static inline jlong tag_for(JvmtiTagMap* tag_map, oop o) {
545 JvmtiTagHashmapEntry* entry = tag_map->hashmap()->find(o);
546 if (entry == NULL) {
547 return 0;
548 } else {
549 return entry->tag();
550 }
551 }
552
553
554 // A CallbackWrapper is a support class for querying and tagging an object
555 // around a callback to a profiler. The constructor does pre-callback
556 // work to get the tag value, klass tag value, ... and the destructor
557 // does the post-callback work of tagging or untagging the object.
558 //
559 // {
560 // CallbackWrapper wrapper(tag_map, o);
561 //
562 // (*callback)(wrapper.klass_tag(), wrapper.obj_size(), wrapper.obj_tag_p(), ...)
563 //
564 // } // wrapper goes out of scope here which results in the destructor
565 // checking to see if the object has been tagged, untagged, or the
566 // tag value has changed.
567 //
568 class CallbackWrapper : public StackObj {
569 private:
570 JvmtiTagMap* _tag_map;
571 JvmtiTagHashmap* _hashmap;
572 JvmtiTagHashmapEntry* _entry;
573 oop _o;
574 jlong _obj_size;
575 jlong _obj_tag;
576 jlong _klass_tag;
577
578 protected:
579 JvmtiTagMap* tag_map() const { return _tag_map; }
580
581 // invoked post-callback to tag, untag, or update the tag of an object
582 void inline post_callback_tag_update(oop o, JvmtiTagHashmap* hashmap,
583 JvmtiTagHashmapEntry* entry, jlong obj_tag);
584 public:
585 CallbackWrapper(JvmtiTagMap* tag_map, oop o) {
586 assert(Thread::current()->is_VM_thread() || tag_map->is_locked(),
587 "MT unsafe or must be VM thread");
588
589 // object to tag
590 _o = o;
591
592 // object size
593 _obj_size = (jlong)_o->size() * wordSize;
594
595 // record the context
596 _tag_map = tag_map;
597 _hashmap = tag_map->hashmap();
598 _entry = _hashmap->find(_o);
599
600 // get object tag
601 _obj_tag = (_entry == NULL) ? 0 : _entry->tag();
602
603 // get the class and the class's tag value
604 assert(SystemDictionary::Class_klass()->is_mirror_instance_klass(), "Is not?");
605
606 _klass_tag = tag_for(tag_map, _o->klass()->java_mirror());
607 }
608
609 ~CallbackWrapper() {
610 post_callback_tag_update(_o, _hashmap, _entry, _obj_tag);
611 }
612
613 inline jlong* obj_tag_p() { return &_obj_tag; }
614 inline jlong obj_size() const { return _obj_size; }
615 inline jlong obj_tag() const { return _obj_tag; }
616 inline jlong klass_tag() const { return _klass_tag; }
617 };
618
619
620
621 // callback post-callback to tag, untag, or update the tag of an object
622 void inline CallbackWrapper::post_callback_tag_update(oop o,
623 JvmtiTagHashmap* hashmap,
624 JvmtiTagHashmapEntry* entry,
625 jlong obj_tag) {
626 if (entry == NULL) {
627 if (obj_tag != 0) {
628 // callback has tagged the object
629 assert(Thread::current()->is_VM_thread(), "must be VMThread");
630 entry = tag_map()->create_entry(o, obj_tag);
631 hashmap->add(o, entry);
632 }
633 } else {
634 // object was previously tagged - the callback may have untagged
635 // the object or changed the tag value
636 if (obj_tag == 0) {
637
638 JvmtiTagHashmapEntry* entry_removed = hashmap->remove(o);
639 assert(entry_removed == entry, "checking");
640 tag_map()->destroy_entry(entry);
641
642 } else {
643 if (obj_tag != entry->tag()) {
644 entry->set_tag(obj_tag);
645 }
646 }
647 }
648 }
649
650 // An extended CallbackWrapper used when reporting an object reference
651 // to the agent.
652 //
653 // {
654 // TwoOopCallbackWrapper wrapper(tag_map, referrer, o);
655 //
656 // (*callback)(wrapper.klass_tag(),
657 // wrapper.obj_size(),
658 // wrapper.obj_tag_p()
659 // wrapper.referrer_tag_p(), ...)
660 //
661 // } // wrapper goes out of scope here which results in the destructor
662 // checking to see if the referrer object has been tagged, untagged,
663 // or the tag value has changed.
664 //
665 class TwoOopCallbackWrapper : public CallbackWrapper {
666 private:
667 bool _is_reference_to_self;
668 JvmtiTagHashmap* _referrer_hashmap;
669 JvmtiTagHashmapEntry* _referrer_entry;
670 oop _referrer;
671 jlong _referrer_obj_tag;
672 jlong _referrer_klass_tag;
673 jlong* _referrer_tag_p;
674
675 bool is_reference_to_self() const { return _is_reference_to_self; }
676
677 public:
678 TwoOopCallbackWrapper(JvmtiTagMap* tag_map, oop referrer, oop o) :
679 CallbackWrapper(tag_map, o)
680 {
681 // self reference needs to be handled in a special way
682 _is_reference_to_self = (referrer == o);
683
684 if (_is_reference_to_self) {
685 _referrer_klass_tag = klass_tag();
686 _referrer_tag_p = obj_tag_p();
687 } else {
688 _referrer = referrer;
689 // record the context
690 _referrer_hashmap = tag_map->hashmap();
691 _referrer_entry = _referrer_hashmap->find(_referrer);
692
693 // get object tag
694 _referrer_obj_tag = (_referrer_entry == NULL) ? 0 : _referrer_entry->tag();
695 _referrer_tag_p = &_referrer_obj_tag;
696
697 // get referrer class tag.
698 _referrer_klass_tag = tag_for(tag_map, _referrer->klass()->java_mirror());
699 }
700 }
701
702 ~TwoOopCallbackWrapper() {
703 if (!is_reference_to_self()){
704 post_callback_tag_update(_referrer,
705 _referrer_hashmap,
706 _referrer_entry,
707 _referrer_obj_tag);
708 }
709 }
710
711 // address of referrer tag
712 // (for a self reference this will return the same thing as obj_tag_p())
713 inline jlong* referrer_tag_p() { return _referrer_tag_p; }
714
715 // referrer's class tag
716 inline jlong referrer_klass_tag() { return _referrer_klass_tag; }
717 };
718
719 // tag an object
720 //
721 // This function is performance critical. If many threads attempt to tag objects
722 // around the same time then it's possible that the Mutex associated with the
723 // tag map will be a hot lock.
724 void JvmtiTagMap::set_tag(jobject object, jlong tag) {
725 MutexLocker ml(lock());
726
727 // resolve the object
728 oop o = JNIHandles::resolve_non_null(object);
729
730 // see if the object is already tagged
731 JvmtiTagHashmap* hashmap = _hashmap;
732 JvmtiTagHashmapEntry* entry = hashmap->find(o);
733
734 // if the object is not already tagged then we tag it
735 if (entry == NULL) {
736 if (tag != 0) {
737 entry = create_entry(o, tag);
738 hashmap->add(o, entry);
739 } else {
740 // no-op
741 }
742 } else {
743 // if the object is already tagged then we either update
744 // the tag (if a new tag value has been provided)
745 // or remove the object if the new tag value is 0.
746 if (tag == 0) {
747 hashmap->remove(o);
748 destroy_entry(entry);
749 } else {
750 entry->set_tag(tag);
751 }
752 }
753 }
754
755 // get the tag for an object
756 jlong JvmtiTagMap::get_tag(jobject object) {
757 MutexLocker ml(lock());
758
759 // resolve the object
760 oop o = JNIHandles::resolve_non_null(object);
761
762 return tag_for(this, o);
763 }
764
765
766 // Helper class used to describe the static or instance fields of a class.
767 // For each field it holds the field index (as defined by the JVMTI specification),
768 // the field type, and the offset.
769
770 class ClassFieldDescriptor: public CHeapObj<mtInternal> {
771 private:
772 int _field_index;
773 int _field_offset;
774 char _field_type;
775 public:
776 ClassFieldDescriptor(int index, char type, int offset) :
777 _field_index(index), _field_offset(offset), _field_type(type) {
778 }
779 int field_index() const { return _field_index; }
780 char field_type() const { return _field_type; }
781 int field_offset() const { return _field_offset; }
782 };
783
784 class ClassFieldMap: public CHeapObj<mtInternal> {
785 private:
786 enum {
787 initial_field_count = 5
788 };
789
790 // list of field descriptors
791 GrowableArray<ClassFieldDescriptor*>* _fields;
792
793 // constructor
794 ClassFieldMap();
795
796 // add a field
797 void add(int index, char type, int offset);
798
799 // returns the field count for the given class
800 static int compute_field_count(InstanceKlass* ik);
801
802 public:
803 ~ClassFieldMap();
804
805 // access
806 int field_count() { return _fields->length(); }
807 ClassFieldDescriptor* field_at(int i) { return _fields->at(i); }
808
809 // functions to create maps of static or instance fields
810 static ClassFieldMap* create_map_of_static_fields(Klass* k);
811 static ClassFieldMap* create_map_of_instance_fields(oop obj);
812 };
813
814 ClassFieldMap::ClassFieldMap() {
815 _fields = new (ResourceObj::C_HEAP, mtInternal)
816 GrowableArray<ClassFieldDescriptor*>(initial_field_count, true);
817 }
818
819 ClassFieldMap::~ClassFieldMap() {
820 for (int i=0; i<_fields->length(); i++) {
821 delete _fields->at(i);
822 }
823 delete _fields;
824 }
825
826 void ClassFieldMap::add(int index, char type, int offset) {
827 ClassFieldDescriptor* field = new ClassFieldDescriptor(index, type, offset);
828 _fields->append(field);
829 }
830
831 // Returns a heap allocated ClassFieldMap to describe the static fields
832 // of the given class.
833 //
834 ClassFieldMap* ClassFieldMap::create_map_of_static_fields(Klass* k) {
835 HandleMark hm;
836 InstanceKlass* ik = InstanceKlass::cast(k);
837
838 // create the field map
839 ClassFieldMap* field_map = new ClassFieldMap();
840
841 FilteredFieldStream f(ik, false, false);
842 int max_field_index = f.field_count()-1;
843
844 int index = 0;
845 for (FilteredFieldStream fld(ik, true, true); !fld.eos(); fld.next(), index++) {
846 // ignore instance fields
847 if (!fld.access_flags().is_static()) {
848 continue;
849 }
850 field_map->add(max_field_index - index, fld.signature()->char_at(0), fld.offset());
851 }
852 return field_map;
853 }
854
855 // Returns a heap allocated ClassFieldMap to describe the instance fields
856 // of the given class. All instance fields are included (this means public
857 // and private fields declared in superclasses and superinterfaces too).
858 //
859 ClassFieldMap* ClassFieldMap::create_map_of_instance_fields(oop obj) {
860 HandleMark hm;
861 InstanceKlass* ik = InstanceKlass::cast(obj->klass());
862
863 // create the field map
864 ClassFieldMap* field_map = new ClassFieldMap();
865
866 FilteredFieldStream f(ik, false, false);
867
868 int max_field_index = f.field_count()-1;
869
870 int index = 0;
871 for (FilteredFieldStream fld(ik, false, false); !fld.eos(); fld.next(), index++) {
872 // ignore static fields
873 if (fld.access_flags().is_static()) {
874 continue;
875 }
876 field_map->add(max_field_index - index, fld.signature()->char_at(0), fld.offset());
877 }
878
879 return field_map;
880 }
881
882 // Helper class used to cache a ClassFileMap for the instance fields of
883 // a cache. A JvmtiCachedClassFieldMap can be cached by an InstanceKlass during
884 // heap iteration and avoid creating a field map for each object in the heap
885 // (only need to create the map when the first instance of a class is encountered).
886 //
887 class JvmtiCachedClassFieldMap : public CHeapObj<mtInternal> {
888 private:
889 enum {
890 initial_class_count = 200
891 };
892 ClassFieldMap* _field_map;
893
894 ClassFieldMap* field_map() const { return _field_map; }
895
896 JvmtiCachedClassFieldMap(ClassFieldMap* field_map);
897 ~JvmtiCachedClassFieldMap();
898
899 static GrowableArray<InstanceKlass*>* _class_list;
900 static void add_to_class_list(InstanceKlass* ik);
901
902 public:
903 // returns the field map for a given object (returning map cached
904 // by InstanceKlass if possible
905 static ClassFieldMap* get_map_of_instance_fields(oop obj);
906
907 // removes the field map from all instanceKlasses - should be
908 // called before VM operation completes
909 static void clear_cache();
910
911 // returns the number of ClassFieldMap cached by instanceKlasses
912 static int cached_field_map_count();
913 };
914
915 GrowableArray<InstanceKlass*>* JvmtiCachedClassFieldMap::_class_list;
916
917 JvmtiCachedClassFieldMap::JvmtiCachedClassFieldMap(ClassFieldMap* field_map) {
918 _field_map = field_map;
919 }
920
921 JvmtiCachedClassFieldMap::~JvmtiCachedClassFieldMap() {
922 if (_field_map != NULL) {
923 delete _field_map;
924 }
925 }
926
927 // Marker class to ensure that the class file map cache is only used in a defined
928 // scope.
929 class ClassFieldMapCacheMark : public StackObj {
930 private:
931 static bool _is_active;
932 public:
933 ClassFieldMapCacheMark() {
934 assert(Thread::current()->is_VM_thread(), "must be VMThread");
935 assert(JvmtiCachedClassFieldMap::cached_field_map_count() == 0, "cache not empty");
936 assert(!_is_active, "ClassFieldMapCacheMark cannot be nested");
937 _is_active = true;
938 }
939 ~ClassFieldMapCacheMark() {
940 JvmtiCachedClassFieldMap::clear_cache();
941 _is_active = false;
942 }
943 static bool is_active() { return _is_active; }
944 };
945
946 bool ClassFieldMapCacheMark::_is_active;
947
948
949 // record that the given InstanceKlass is caching a field map
950 void JvmtiCachedClassFieldMap::add_to_class_list(InstanceKlass* ik) {
951 if (_class_list == NULL) {
952 _class_list = new (ResourceObj::C_HEAP, mtInternal)
953 GrowableArray<InstanceKlass*>(initial_class_count, true);
954 }
955 _class_list->push(ik);
956 }
957
958 // returns the instance field map for the given object
959 // (returns field map cached by the InstanceKlass if possible)
960 ClassFieldMap* JvmtiCachedClassFieldMap::get_map_of_instance_fields(oop obj) {
961 assert(Thread::current()->is_VM_thread(), "must be VMThread");
962 assert(ClassFieldMapCacheMark::is_active(), "ClassFieldMapCacheMark not active");
963
964 Klass* k = obj->klass();
965 InstanceKlass* ik = InstanceKlass::cast(k);
966
967 // return cached map if possible
968 JvmtiCachedClassFieldMap* cached_map = ik->jvmti_cached_class_field_map();
969 if (cached_map != NULL) {
970 assert(cached_map->field_map() != NULL, "missing field list");
971 return cached_map->field_map();
972 } else {
973 ClassFieldMap* field_map = ClassFieldMap::create_map_of_instance_fields(obj);
974 cached_map = new JvmtiCachedClassFieldMap(field_map);
975 ik->set_jvmti_cached_class_field_map(cached_map);
976 add_to_class_list(ik);
977 return field_map;
978 }
979 }
980
981 // remove the fields maps cached from all instanceKlasses
982 void JvmtiCachedClassFieldMap::clear_cache() {
983 assert(Thread::current()->is_VM_thread(), "must be VMThread");
984 if (_class_list != NULL) {
985 for (int i = 0; i < _class_list->length(); i++) {
986 InstanceKlass* ik = _class_list->at(i);
987 JvmtiCachedClassFieldMap* cached_map = ik->jvmti_cached_class_field_map();
988 assert(cached_map != NULL, "should not be NULL");
989 ik->set_jvmti_cached_class_field_map(NULL);
990 delete cached_map; // deletes the encapsulated field map
991 }
992 delete _class_list;
993 _class_list = NULL;
994 }
995 }
996
997 // returns the number of ClassFieldMap cached by instanceKlasses
998 int JvmtiCachedClassFieldMap::cached_field_map_count() {
999 return (_class_list == NULL) ? 0 : _class_list->length();
1000 }
1001
1002 // helper function to indicate if an object is filtered by its tag or class tag
1003 static inline bool is_filtered_by_heap_filter(jlong obj_tag,
1004 jlong klass_tag,
1005 int heap_filter) {
1006 // apply the heap filter
1007 if (obj_tag != 0) {
1008 // filter out tagged objects
1009 if (heap_filter & JVMTI_HEAP_FILTER_TAGGED) return true;
1010 } else {
1011 // filter out untagged objects
1012 if (heap_filter & JVMTI_HEAP_FILTER_UNTAGGED) return true;
1013 }
1014 if (klass_tag != 0) {
1015 // filter out objects with tagged classes
1016 if (heap_filter & JVMTI_HEAP_FILTER_CLASS_TAGGED) return true;
1017 } else {
1018 // filter out objects with untagged classes.
1019 if (heap_filter & JVMTI_HEAP_FILTER_CLASS_UNTAGGED) return true;
1020 }
1021 return false;
1022 }
1023
1024 // helper function to indicate if an object is filtered by a klass filter
1025 static inline bool is_filtered_by_klass_filter(oop obj, Klass* klass_filter) {
1026 if (klass_filter != NULL) {
1027 if (obj->klass() != klass_filter) {
1028 return true;
1029 }
1030 }
1031 return false;
1032 }
1033
1034 // helper function to tell if a field is a primitive field or not
1035 static inline bool is_primitive_field_type(char type) {
1036 return (type != 'L' && type != '[');
1037 }
1038
1039 // helper function to copy the value from location addr to jvalue.
1040 static inline void copy_to_jvalue(jvalue *v, address addr, jvmtiPrimitiveType value_type) {
1041 switch (value_type) {
1042 case JVMTI_PRIMITIVE_TYPE_BOOLEAN : { v->z = *(jboolean*)addr; break; }
1043 case JVMTI_PRIMITIVE_TYPE_BYTE : { v->b = *(jbyte*)addr; break; }
1044 case JVMTI_PRIMITIVE_TYPE_CHAR : { v->c = *(jchar*)addr; break; }
1045 case JVMTI_PRIMITIVE_TYPE_SHORT : { v->s = *(jshort*)addr; break; }
1046 case JVMTI_PRIMITIVE_TYPE_INT : { v->i = *(jint*)addr; break; }
1047 case JVMTI_PRIMITIVE_TYPE_LONG : { v->j = *(jlong*)addr; break; }
1048 case JVMTI_PRIMITIVE_TYPE_FLOAT : { v->f = *(jfloat*)addr; break; }
1049 case JVMTI_PRIMITIVE_TYPE_DOUBLE : { v->d = *(jdouble*)addr; break; }
1050 default: ShouldNotReachHere();
1051 }
1052 }
1053
1054 // helper function to invoke string primitive value callback
1055 // returns visit control flags
1056 static jint invoke_string_value_callback(jvmtiStringPrimitiveValueCallback cb,
1057 CallbackWrapper* wrapper,
1058 oop str,
1059 void* user_data)
1060 {
1061 assert(str->klass() == SystemDictionary::String_klass(), "not a string");
1062
1063 typeArrayOop s_value = java_lang_String::value(str);
1064
1065 // JDK-6584008: the value field may be null if a String instance is
1066 // partially constructed.
1067 if (s_value == NULL) {
1068 return 0;
1069 }
1070 // get the string value and length
1071 // (string value may be offset from the base)
1072 int s_len = java_lang_String::length(str);
1073 bool is_latin1 = java_lang_String::is_latin1(str);
1074 jchar* value;
1075 if (s_len > 0) {
1076 if (!is_latin1) {
1077 value = s_value->char_at_addr(0);
1078 } else {
1079 // Inflate latin1 encoded string to UTF16
1080 jchar* buf = NEW_C_HEAP_ARRAY(jchar, s_len, mtInternal);
1081 for (int i = 0; i < s_len; i++) {
1082 buf[i] = ((jchar) s_value->byte_at(i)) & 0xff;
1083 }
1084 value = &buf[0];
1085 }
1086 } else {
1087 // Don't use char_at_addr(0) if length is 0
1088 value = (jchar*) s_value->base(T_CHAR);
1089 }
1090
1091 // invoke the callback
1092 jint res = (*cb)(wrapper->klass_tag(),
1093 wrapper->obj_size(),
1094 wrapper->obj_tag_p(),
1095 value,
1096 (jint)s_len,
1097 user_data);
1098
1099 if (is_latin1 && s_len > 0) {
1100 FREE_C_HEAP_ARRAY(jchar, value);
1101 }
1102 return res;
1103 }
1104
1105 // helper function to invoke string primitive value callback
1106 // returns visit control flags
1107 static jint invoke_array_primitive_value_callback(jvmtiArrayPrimitiveValueCallback cb,
1108 CallbackWrapper* wrapper,
1109 oop obj,
1110 void* user_data)
1111 {
1112 assert(obj->is_typeArray(), "not a primitive array");
1113
1114 // get base address of first element
1115 typeArrayOop array = typeArrayOop(obj);
1116 BasicType type = TypeArrayKlass::cast(array->klass())->element_type();
1117 void* elements = array->base(type);
1118
1119 // jvmtiPrimitiveType is defined so this mapping is always correct
1120 jvmtiPrimitiveType elem_type = (jvmtiPrimitiveType)type2char(type);
1121
1122 return (*cb)(wrapper->klass_tag(),
1123 wrapper->obj_size(),
1124 wrapper->obj_tag_p(),
1125 (jint)array->length(),
1126 elem_type,
1127 elements,
1128 user_data);
1129 }
1130
1131 // helper function to invoke the primitive field callback for all static fields
1132 // of a given class
1133 static jint invoke_primitive_field_callback_for_static_fields
1134 (CallbackWrapper* wrapper,
1135 oop obj,
1136 jvmtiPrimitiveFieldCallback cb,
1137 void* user_data)
1138 {
1139 // for static fields only the index will be set
1140 static jvmtiHeapReferenceInfo reference_info = { 0 };
1141
1142 assert(obj->klass() == SystemDictionary::Class_klass(), "not a class");
1143 if (java_lang_Class::is_primitive(obj)) {
1144 return 0;
1145 }
1146 Klass* klass = java_lang_Class::as_Klass(obj);
1147
1148 // ignore classes for object and type arrays
1149 if (!klass->is_instance_klass()) {
1150 return 0;
1151 }
1152
1153 // ignore classes which aren't linked yet
1154 InstanceKlass* ik = InstanceKlass::cast(klass);
1155 if (!ik->is_linked()) {
1156 return 0;
1157 }
1158
1159 // get the field map
1160 ClassFieldMap* field_map = ClassFieldMap::create_map_of_static_fields(klass);
1161
1162 // invoke the callback for each static primitive field
1163 for (int i=0; i<field_map->field_count(); i++) {
1164 ClassFieldDescriptor* field = field_map->field_at(i);
1165
1166 // ignore non-primitive fields
1167 char type = field->field_type();
1168 if (!is_primitive_field_type(type)) {
1169 continue;
1170 }
1171 // one-to-one mapping
1172 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
1173
1174 // get offset and field value
1175 int offset = field->field_offset();
1176 address addr = (address)klass->java_mirror() + offset;
1177 jvalue value;
1178 copy_to_jvalue(&value, addr, value_type);
1179
1180 // field index
1181 reference_info.field.index = field->field_index();
1182
1183 // invoke the callback
1184 jint res = (*cb)(JVMTI_HEAP_REFERENCE_STATIC_FIELD,
1185 &reference_info,
1186 wrapper->klass_tag(),
1187 wrapper->obj_tag_p(),
1188 value,
1189 value_type,
1190 user_data);
1191 if (res & JVMTI_VISIT_ABORT) {
1192 delete field_map;
1193 return res;
1194 }
1195 }
1196
1197 delete field_map;
1198 return 0;
1199 }
1200
1201 // helper function to invoke the primitive field callback for all instance fields
1202 // of a given object
1203 static jint invoke_primitive_field_callback_for_instance_fields(
1204 CallbackWrapper* wrapper,
1205 oop obj,
1206 jvmtiPrimitiveFieldCallback cb,
1207 void* user_data)
1208 {
1209 // for instance fields only the index will be set
1210 static jvmtiHeapReferenceInfo reference_info = { 0 };
1211
1212 // get the map of the instance fields
1213 ClassFieldMap* fields = JvmtiCachedClassFieldMap::get_map_of_instance_fields(obj);
1214
1215 // invoke the callback for each instance primitive field
1216 for (int i=0; i<fields->field_count(); i++) {
1217 ClassFieldDescriptor* field = fields->field_at(i);
1218
1219 // ignore non-primitive fields
1220 char type = field->field_type();
1221 if (!is_primitive_field_type(type)) {
1222 continue;
1223 }
1224 // one-to-one mapping
1225 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
1226
1227 // get offset and field value
1228 int offset = field->field_offset();
1229 address addr = (address)obj + offset;
1230 jvalue value;
1231 copy_to_jvalue(&value, addr, value_type);
1232
1233 // field index
1234 reference_info.field.index = field->field_index();
1235
1236 // invoke the callback
1237 jint res = (*cb)(JVMTI_HEAP_REFERENCE_FIELD,
1238 &reference_info,
1239 wrapper->klass_tag(),
1240 wrapper->obj_tag_p(),
1241 value,
1242 value_type,
1243 user_data);
1244 if (res & JVMTI_VISIT_ABORT) {
1245 return res;
1246 }
1247 }
1248 return 0;
1249 }
1250
1251
1252 // VM operation to iterate over all objects in the heap (both reachable
1253 // and unreachable)
1254 class VM_HeapIterateOperation: public VM_Operation {
1255 private:
1256 ObjectClosure* _blk;
1257 public:
1258 VM_HeapIterateOperation(ObjectClosure* blk) { _blk = blk; }
1259
1260 VMOp_Type type() const { return VMOp_HeapIterateOperation; }
1261 void doit() {
1262 // allows class files maps to be cached during iteration
1263 ClassFieldMapCacheMark cm;
1264
1265 // make sure that heap is parsable (fills TLABs with filler objects)
1266 Universe::heap()->ensure_parsability(false); // no need to retire TLABs
1267
1268 // Verify heap before iteration - if the heap gets corrupted then
1269 // JVMTI's IterateOverHeap will crash.
1270 if (VerifyBeforeIteration) {
1271 Universe::verify();
1272 }
1273
1274 // do the iteration
1275 // If this operation encounters a bad object when using CMS,
1276 // consider using safe_object_iterate() which avoids perm gen
1277 // objects that may contain bad references.
1278 Universe::heap()->object_iterate(_blk);
1279 }
1280
1281 };
1282
1283
1284 // An ObjectClosure used to support the deprecated IterateOverHeap and
1285 // IterateOverInstancesOfClass functions
1286 class IterateOverHeapObjectClosure: public ObjectClosure {
1287 private:
1288 JvmtiTagMap* _tag_map;
1289 Klass* _klass;
1290 jvmtiHeapObjectFilter _object_filter;
1291 jvmtiHeapObjectCallback _heap_object_callback;
1292 const void* _user_data;
1293
1294 // accessors
1295 JvmtiTagMap* tag_map() const { return _tag_map; }
1296 jvmtiHeapObjectFilter object_filter() const { return _object_filter; }
1297 jvmtiHeapObjectCallback object_callback() const { return _heap_object_callback; }
1298 Klass* klass() const { return _klass; }
1299 const void* user_data() const { return _user_data; }
1300
1301 // indicates if iteration has been aborted
1302 bool _iteration_aborted;
1303 bool is_iteration_aborted() const { return _iteration_aborted; }
1304 void set_iteration_aborted(bool aborted) { _iteration_aborted = aborted; }
1305
1306 public:
1307 IterateOverHeapObjectClosure(JvmtiTagMap* tag_map,
1308 Klass* klass,
1309 jvmtiHeapObjectFilter object_filter,
1310 jvmtiHeapObjectCallback heap_object_callback,
1311 const void* user_data) :
1312 _tag_map(tag_map),
1313 _klass(klass),
1314 _object_filter(object_filter),
1315 _heap_object_callback(heap_object_callback),
1316 _user_data(user_data),
1317 _iteration_aborted(false)
1318 {
1319 }
1320
1321 void do_object(oop o);
1322 };
1323
1324 // invoked for each object in the heap
1325 void IterateOverHeapObjectClosure::do_object(oop o) {
1326 // check if iteration has been halted
1327 if (is_iteration_aborted()) return;
1328
1329 // instanceof check when filtering by klass
1330 if (klass() != 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 Klass* _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 Klass* 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 Klass* 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 // apply class filter
1410 if (is_filtered_by_klass_filter(obj, klass())) return;
1411
1412 // prepare for callback
1413 CallbackWrapper wrapper(tag_map(), obj);
1414
1415 // check if filtered by the heap filter
1416 if (is_filtered_by_heap_filter(wrapper.obj_tag(), wrapper.klass_tag(), heap_filter())) {
1417 return;
1418 }
1419
1420 // for arrays we need the length, otherwise -1
1421 bool is_array = obj->is_array();
1422 int len = is_array ? arrayOop(obj)->length() : -1;
1423
1424 // invoke the object callback (if callback is provided)
1425 if (callbacks()->heap_iteration_callback != NULL) {
1426 jvmtiHeapIterationCallback cb = callbacks()->heap_iteration_callback;
1427 jint res = (*cb)(wrapper.klass_tag(),
1428 wrapper.obj_size(),
1429 wrapper.obj_tag_p(),
1430 (jint)len,
1431 (void*)user_data());
1432 if (check_flags_for_abort(res)) return;
1433 }
1434
1435 // for objects and classes we report primitive fields if callback provided
1436 if (callbacks()->primitive_field_callback != NULL && obj->is_instance()) {
1437 jint res;
1438 jvmtiPrimitiveFieldCallback cb = callbacks()->primitive_field_callback;
1439 if (obj->klass() == SystemDictionary::Class_klass()) {
1440 res = invoke_primitive_field_callback_for_static_fields(&wrapper,
1441 obj,
1442 cb,
1443 (void*)user_data());
1444 } else {
1445 res = invoke_primitive_field_callback_for_instance_fields(&wrapper,
1446 obj,
1447 cb,
1448 (void*)user_data());
1449 }
1450 if (check_flags_for_abort(res)) return;
1451 }
1452
1453 // string callback
1454 if (!is_array &&
1455 callbacks()->string_primitive_value_callback != NULL &&
1456 obj->klass() == SystemDictionary::String_klass()) {
1457 jint res = invoke_string_value_callback(
1458 callbacks()->string_primitive_value_callback,
1459 &wrapper,
1460 obj,
1461 (void*)user_data() );
1462 if (check_flags_for_abort(res)) return;
1463 }
1464
1465 // array callback
1466 if (is_array &&
1467 callbacks()->array_primitive_value_callback != NULL &&
1468 obj->is_typeArray()) {
1469 jint res = invoke_array_primitive_value_callback(
1470 callbacks()->array_primitive_value_callback,
1471 &wrapper,
1472 obj,
1473 (void*)user_data() );
1474 if (check_flags_for_abort(res)) return;
1475 }
1476 };
1477
1478
1479 // Deprecated function to iterate over all objects in the heap
1480 void JvmtiTagMap::iterate_over_heap(jvmtiHeapObjectFilter object_filter,
1481 Klass* klass,
1482 jvmtiHeapObjectCallback heap_object_callback,
1483 const void* user_data)
1484 {
1485 // EA based optimizations on tagged objects are already reverted.
1486 JVMTIEscapeBarrier eb(JavaThread::current(),
1487 object_filter == JVMTI_HEAP_OBJECT_UNTAGGED || object_filter == JVMTI_HEAP_OBJECT_EITHER);
1488 eb.deoptimize_objects_all_threads();
1489 MutexLocker ml(Heap_lock);
1490 IterateOverHeapObjectClosure blk(this,
1491 klass,
1492 object_filter,
1493 heap_object_callback,
1494 user_data);
1495 VM_HeapIterateOperation op(&blk);
1496 VMThread::execute(&op);
1497 }
1498
1499
1500 // Iterates over all objects in the heap
1501 void JvmtiTagMap::iterate_through_heap(jint heap_filter,
1502 Klass* klass,
1503 const jvmtiHeapCallbacks* callbacks,
1504 const void* user_data)
1505 {
1506 // EA based optimizations on tagged objects are already reverted.
1507 JVMTIEscapeBarrier eb(JavaThread::current(), !(heap_filter & JVMTI_HEAP_FILTER_UNTAGGED));
1508 eb.deoptimize_objects_all_threads();
1509 MutexLocker ml(Heap_lock);
1510 IterateThroughHeapObjectClosure blk(this,
1511 klass,
1512 heap_filter,
1513 callbacks,
1514 user_data);
1515 VM_HeapIterateOperation op(&blk);
1516 VMThread::execute(&op);
1517 }
1518
1519 // support class for get_objects_with_tags
1520
1521 class TagObjectCollector : public JvmtiTagHashmapEntryClosure {
1522 private:
1523 JvmtiEnv* _env;
1524 jlong* _tags;
1525 jint _tag_count;
1526
1527 GrowableArray<jobject>* _object_results; // collected objects (JNI weak refs)
1528 GrowableArray<uint64_t>* _tag_results; // collected tags
1529
1530 public:
1531 TagObjectCollector(JvmtiEnv* env, const jlong* tags, jint tag_count) {
1532 _env = env;
1533 _tags = (jlong*)tags;
1534 _tag_count = tag_count;
1535 _object_results = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<jobject>(1,true);
1536 _tag_results = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<uint64_t>(1,true);
1537 }
1538
1539 ~TagObjectCollector() {
1540 delete _object_results;
1541 delete _tag_results;
1542 }
1543
1544 // for each tagged object check if the tag value matches
1545 // - if it matches then we create a JNI local reference to the object
1546 // and record the reference and tag value.
1547 //
1548 void do_entry(JvmtiTagHashmapEntry* entry) {
1549 for (int i=0; i<_tag_count; i++) {
1550 if (_tags[i] == entry->tag()) {
1551 // The reference in this tag map could be the only (implicitly weak)
1552 // reference to that object. If we hand it out, we need to keep it live wrt
1553 // SATB marking similar to other j.l.ref.Reference referents. This is
1554 // achieved by using a phantom load in the object() accessor.
1555 oop o = entry->object();
1556 assert(o != NULL && Universe::heap()->is_in_reserved(o), "sanity check");
1557 jobject ref = JNIHandles::make_local(JavaThread::current(), o);
1558 _object_results->append(ref);
1559 _tag_results->append((uint64_t)entry->tag());
1560 }
1561 }
1562 }
1563
1564 // return the results from the collection
1565 //
1566 jvmtiError result(jint* count_ptr, jobject** object_result_ptr, jlong** tag_result_ptr) {
1567 jvmtiError error;
1568 int count = _object_results->length();
1569 assert(count >= 0, "sanity check");
1570
1571 // if object_result_ptr is not NULL then allocate the result and copy
1572 // in the object references.
1573 if (object_result_ptr != NULL) {
1574 error = _env->Allocate(count * sizeof(jobject), (unsigned char**)object_result_ptr);
1575 if (error != JVMTI_ERROR_NONE) {
1576 return error;
1577 }
1578 for (int i=0; i<count; i++) {
1579 (*object_result_ptr)[i] = _object_results->at(i);
1580 }
1581 }
1582
1583 // if tag_result_ptr is not NULL then allocate the result and copy
1584 // in the tag values.
1585 if (tag_result_ptr != NULL) {
1586 error = _env->Allocate(count * sizeof(jlong), (unsigned char**)tag_result_ptr);
1587 if (error != JVMTI_ERROR_NONE) {
1588 if (object_result_ptr != NULL) {
1589 _env->Deallocate((unsigned char*)object_result_ptr);
1590 }
1591 return error;
1592 }
1593 for (int i=0; i<count; i++) {
1594 (*tag_result_ptr)[i] = (jlong)_tag_results->at(i);
1595 }
1596 }
1597
1598 *count_ptr = count;
1599 return JVMTI_ERROR_NONE;
1600 }
1601 };
1602
1603 // return the list of objects with the specified tags
1604 jvmtiError JvmtiTagMap::get_objects_with_tags(const jlong* tags,
1605 jint count, jint* count_ptr, jobject** object_result_ptr, jlong** tag_result_ptr) {
1606
1607 TagObjectCollector collector(env(), tags, count);
1608 {
1609 // iterate over all tagged objects
1610 MutexLocker ml(lock());
1611 entry_iterate(&collector);
1612 }
1613 return collector.result(count_ptr, object_result_ptr, tag_result_ptr);
1614 }
1615
1616
1617 // ObjectMarker is used to support the marking objects when walking the
1618 // heap.
1619 //
1620 // This implementation uses the existing mark bits in an object for
1621 // marking. Objects that are marked must later have their headers restored.
1622 // As most objects are unlocked and don't have their identity hash computed
1623 // we don't have to save their headers. Instead we save the headers that
1624 // are "interesting". Later when the headers are restored this implementation
1625 // restores all headers to their initial value and then restores the few
1626 // objects that had interesting headers.
1627 //
1628 // Future work: This implementation currently uses growable arrays to save
1629 // the oop and header of interesting objects. As an optimization we could
1630 // use the same technique as the GC and make use of the unused area
1631 // between top() and end().
1632 //
1633
1634 // An ObjectClosure used to restore the mark bits of an object
1635 class RestoreMarksClosure : public ObjectClosure {
1636 public:
1637 void do_object(oop o) {
1638 if (o != NULL) {
1639 markWord mark = o->mark();
1640 if (mark.is_marked()) {
1641 o->init_mark();
1642 }
1643 }
1644 }
1645 };
1646
1647 // ObjectMarker provides the mark and visited functions
1648 class ObjectMarker : AllStatic {
1649 private:
1650 // saved headers
1651 static GrowableArray<oop>* _saved_oop_stack;
1652 static GrowableArray<markWord>* _saved_mark_stack;
1653 static bool _needs_reset; // do we need to reset mark bits?
1654
1655 public:
1656 static void init(); // initialize
1657 static void done(); // clean-up
1658
1659 static inline void mark(oop o); // mark an object
1660 static inline bool visited(oop o); // check if object has been visited
1661
1662 static inline bool needs_reset() { return _needs_reset; }
1663 static inline void set_needs_reset(bool v) { _needs_reset = v; }
1664 };
1665
1666 GrowableArray<oop>* ObjectMarker::_saved_oop_stack = NULL;
1667 GrowableArray<markWord>* ObjectMarker::_saved_mark_stack = NULL;
1668 bool ObjectMarker::_needs_reset = true; // need to reset mark bits by default
1669
1670 // initialize ObjectMarker - prepares for object marking
1671 void ObjectMarker::init() {
1672 assert(Thread::current()->is_VM_thread(), "must be VMThread");
1673
1674 // prepare heap for iteration
1675 Universe::heap()->ensure_parsability(false); // no need to retire TLABs
1676
1677 // create stacks for interesting headers
1678 _saved_mark_stack = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<markWord>(4000, true);
1679 _saved_oop_stack = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(4000, true);
1680
1681 if (UseBiasedLocking) {
1682 BiasedLocking::preserve_marks();
1683 }
1684 }
1685
1686 // Object marking is done so restore object headers
1687 void ObjectMarker::done() {
1688 // iterate over all objects and restore the mark bits to
1689 // their initial value
1690 RestoreMarksClosure blk;
1691 if (needs_reset()) {
1692 Universe::heap()->object_iterate(&blk);
1693 } else {
1694 // We don't need to reset mark bits on this call, but reset the
1695 // flag to the default for the next call.
1696 set_needs_reset(true);
1697 }
1698
1699 // now restore the interesting headers
1700 for (int i = 0; i < _saved_oop_stack->length(); i++) {
1701 oop o = _saved_oop_stack->at(i);
1702 markWord mark = _saved_mark_stack->at(i);
1703 o->set_mark(mark);
1704 }
1705
1706 if (UseBiasedLocking) {
1707 BiasedLocking::restore_marks();
1708 }
1709
1710 // free the stacks
1711 delete _saved_oop_stack;
1712 delete _saved_mark_stack;
1713 }
1714
1715 // mark an object
1716 inline void ObjectMarker::mark(oop o) {
1717 assert(Universe::heap()->is_in(o), "sanity check");
1718 assert(!o->mark().is_marked(), "should only mark an object once");
1719
1720 // object's mark word
1721 markWord mark = o->mark();
1722
1723 if (o->mark_must_be_preserved(mark)) {
1724 _saved_mark_stack->push(mark);
1725 _saved_oop_stack->push(o);
1726 }
1727
1728 // mark the object
1729 o->set_mark(markWord::prototype().set_marked());
1730 }
1731
1732 // return true if object is marked
1733 inline bool ObjectMarker::visited(oop o) {
1734 return o->mark().is_marked();
1735 }
1736
1737 // Stack allocated class to help ensure that ObjectMarker is used
1738 // correctly. Constructor initializes ObjectMarker, destructor calls
1739 // ObjectMarker's done() function to restore object headers.
1740 class ObjectMarkerController : public StackObj {
1741 public:
1742 ObjectMarkerController() {
1743 ObjectMarker::init();
1744 }
1745 ~ObjectMarkerController() {
1746 ObjectMarker::done();
1747 }
1748 };
1749
1750
1751 // helper to map a jvmtiHeapReferenceKind to an old style jvmtiHeapRootKind
1752 // (not performance critical as only used for roots)
1753 static jvmtiHeapRootKind toJvmtiHeapRootKind(jvmtiHeapReferenceKind kind) {
1754 switch (kind) {
1755 case JVMTI_HEAP_REFERENCE_JNI_GLOBAL: return JVMTI_HEAP_ROOT_JNI_GLOBAL;
1756 case JVMTI_HEAP_REFERENCE_SYSTEM_CLASS: return JVMTI_HEAP_ROOT_SYSTEM_CLASS;
1757 case JVMTI_HEAP_REFERENCE_MONITOR: return JVMTI_HEAP_ROOT_MONITOR;
1758 case JVMTI_HEAP_REFERENCE_STACK_LOCAL: return JVMTI_HEAP_ROOT_STACK_LOCAL;
1759 case JVMTI_HEAP_REFERENCE_JNI_LOCAL: return JVMTI_HEAP_ROOT_JNI_LOCAL;
1760 case JVMTI_HEAP_REFERENCE_THREAD: return JVMTI_HEAP_ROOT_THREAD;
1761 case JVMTI_HEAP_REFERENCE_OTHER: return JVMTI_HEAP_ROOT_OTHER;
1762 default: ShouldNotReachHere(); return JVMTI_HEAP_ROOT_OTHER;
1763 }
1764 }
1765
1766 // Base class for all heap walk contexts. The base class maintains a flag
1767 // to indicate if the context is valid or not.
1768 class HeapWalkContext {
1769 private:
1770 bool _valid;
1771 public:
1772 HeapWalkContext(bool valid) { _valid = valid; }
1773 void invalidate() { _valid = false; }
1774 bool is_valid() const { return _valid; }
1775 };
1776
1777 // A basic heap walk context for the deprecated heap walking functions.
1778 // The context for a basic heap walk are the callbacks and fields used by
1779 // the referrer caching scheme.
1780 class BasicHeapWalkContext: public HeapWalkContext {
1781 private:
1782 jvmtiHeapRootCallback _heap_root_callback;
1783 jvmtiStackReferenceCallback _stack_ref_callback;
1784 jvmtiObjectReferenceCallback _object_ref_callback;
1785
1786 // used for caching
1787 oop _last_referrer;
1788 jlong _last_referrer_tag;
1789
1790 public:
1791 BasicHeapWalkContext() : HeapWalkContext(false) { }
1792
1793 BasicHeapWalkContext(jvmtiHeapRootCallback heap_root_callback,
1794 jvmtiStackReferenceCallback stack_ref_callback,
1795 jvmtiObjectReferenceCallback object_ref_callback) :
1796 HeapWalkContext(true),
1797 _heap_root_callback(heap_root_callback),
1798 _stack_ref_callback(stack_ref_callback),
1799 _object_ref_callback(object_ref_callback),
1800 _last_referrer(NULL),
1801 _last_referrer_tag(0) {
1802 }
1803
1804 // accessors
1805 jvmtiHeapRootCallback heap_root_callback() const { return _heap_root_callback; }
1806 jvmtiStackReferenceCallback stack_ref_callback() const { return _stack_ref_callback; }
1807 jvmtiObjectReferenceCallback object_ref_callback() const { return _object_ref_callback; }
1808
1809 oop last_referrer() const { return _last_referrer; }
1810 void set_last_referrer(oop referrer) { _last_referrer = referrer; }
1811 jlong last_referrer_tag() const { return _last_referrer_tag; }
1812 void set_last_referrer_tag(jlong value) { _last_referrer_tag = value; }
1813 };
1814
1815 // The advanced heap walk context for the FollowReferences functions.
1816 // The context is the callbacks, and the fields used for filtering.
1817 class AdvancedHeapWalkContext: public HeapWalkContext {
1818 private:
1819 jint _heap_filter;
1820 Klass* _klass_filter;
1821 const jvmtiHeapCallbacks* _heap_callbacks;
1822
1823 public:
1824 AdvancedHeapWalkContext() : HeapWalkContext(false) { }
1825
1826 AdvancedHeapWalkContext(jint heap_filter,
1827 Klass* klass_filter,
1828 const jvmtiHeapCallbacks* heap_callbacks) :
1829 HeapWalkContext(true),
1830 _heap_filter(heap_filter),
1831 _klass_filter(klass_filter),
1832 _heap_callbacks(heap_callbacks) {
1833 }
1834
1835 // accessors
1836 jint heap_filter() const { return _heap_filter; }
1837 Klass* klass_filter() const { return _klass_filter; }
1838
1839 const jvmtiHeapReferenceCallback heap_reference_callback() const {
1840 return _heap_callbacks->heap_reference_callback;
1841 };
1842 const jvmtiPrimitiveFieldCallback primitive_field_callback() const {
1843 return _heap_callbacks->primitive_field_callback;
1844 }
1845 const jvmtiArrayPrimitiveValueCallback array_primitive_value_callback() const {
1846 return _heap_callbacks->array_primitive_value_callback;
1847 }
1848 const jvmtiStringPrimitiveValueCallback string_primitive_value_callback() const {
1849 return _heap_callbacks->string_primitive_value_callback;
1850 }
1851 };
1852
1853 // The CallbackInvoker is a class with static functions that the heap walk can call
1854 // into to invoke callbacks. It works in one of two modes. The "basic" mode is
1855 // used for the deprecated IterateOverReachableObjects functions. The "advanced"
1856 // mode is for the newer FollowReferences function which supports a lot of
1857 // additional callbacks.
1858 class CallbackInvoker : AllStatic {
1859 private:
1860 // heap walk styles
1861 enum { basic, advanced };
1862 static int _heap_walk_type;
1863 static bool is_basic_heap_walk() { return _heap_walk_type == basic; }
1864 static bool is_advanced_heap_walk() { return _heap_walk_type == advanced; }
1865
1866 // context for basic style heap walk
1867 static BasicHeapWalkContext _basic_context;
1868 static BasicHeapWalkContext* basic_context() {
1869 assert(_basic_context.is_valid(), "invalid");
1870 return &_basic_context;
1871 }
1872
1873 // context for advanced style heap walk
1874 static AdvancedHeapWalkContext _advanced_context;
1875 static AdvancedHeapWalkContext* advanced_context() {
1876 assert(_advanced_context.is_valid(), "invalid");
1877 return &_advanced_context;
1878 }
1879
1880 // context needed for all heap walks
1881 static JvmtiTagMap* _tag_map;
1882 static const void* _user_data;
1883 static GrowableArray<oop>* _visit_stack;
1884
1885 // accessors
1886 static JvmtiTagMap* tag_map() { return _tag_map; }
1887 static const void* user_data() { return _user_data; }
1888 static GrowableArray<oop>* visit_stack() { return _visit_stack; }
1889
1890 // if the object hasn't been visited then push it onto the visit stack
1891 // so that it will be visited later
1892 static inline bool check_for_visit(oop obj) {
1893 if (!ObjectMarker::visited(obj)) visit_stack()->push(obj);
1894 return true;
1895 }
1896
1897 // invoke basic style callbacks
1898 static inline bool invoke_basic_heap_root_callback
1899 (jvmtiHeapRootKind root_kind, oop obj);
1900 static inline bool invoke_basic_stack_ref_callback
1901 (jvmtiHeapRootKind root_kind, jlong thread_tag, jint depth, jmethodID method,
1902 int slot, oop obj);
1903 static inline bool invoke_basic_object_reference_callback
1904 (jvmtiObjectReferenceKind ref_kind, oop referrer, oop referree, jint index);
1905
1906 // invoke advanced style callbacks
1907 static inline bool invoke_advanced_heap_root_callback
1908 (jvmtiHeapReferenceKind ref_kind, oop obj);
1909 static inline bool invoke_advanced_stack_ref_callback
1910 (jvmtiHeapReferenceKind ref_kind, jlong thread_tag, jlong tid, int depth,
1911 jmethodID method, jlocation bci, jint slot, oop obj);
1912 static inline bool invoke_advanced_object_reference_callback
1913 (jvmtiHeapReferenceKind ref_kind, oop referrer, oop referree, jint index);
1914
1915 // used to report the value of primitive fields
1916 static inline bool report_primitive_field
1917 (jvmtiHeapReferenceKind ref_kind, oop obj, jint index, address addr, char type);
1918
1919 public:
1920 // initialize for basic mode
1921 static void initialize_for_basic_heap_walk(JvmtiTagMap* tag_map,
1922 GrowableArray<oop>* visit_stack,
1923 const void* user_data,
1924 BasicHeapWalkContext context);
1925
1926 // initialize for advanced mode
1927 static void initialize_for_advanced_heap_walk(JvmtiTagMap* tag_map,
1928 GrowableArray<oop>* visit_stack,
1929 const void* user_data,
1930 AdvancedHeapWalkContext context);
1931
1932 // functions to report roots
1933 static inline bool report_simple_root(jvmtiHeapReferenceKind kind, oop o);
1934 static inline bool report_jni_local_root(jlong thread_tag, jlong tid, jint depth,
1935 jmethodID m, oop o);
1936 static inline bool report_stack_ref_root(jlong thread_tag, jlong tid, jint depth,
1937 jmethodID method, jlocation bci, jint slot, oop o);
1938
1939 // functions to report references
1940 static inline bool report_array_element_reference(oop referrer, oop referree, jint index);
1941 static inline bool report_class_reference(oop referrer, oop referree);
1942 static inline bool report_class_loader_reference(oop referrer, oop referree);
1943 static inline bool report_signers_reference(oop referrer, oop referree);
1944 static inline bool report_protection_domain_reference(oop referrer, oop referree);
1945 static inline bool report_superclass_reference(oop referrer, oop referree);
1946 static inline bool report_interface_reference(oop referrer, oop referree);
1947 static inline bool report_static_field_reference(oop referrer, oop referree, jint slot);
1948 static inline bool report_field_reference(oop referrer, oop referree, jint slot);
1949 static inline bool report_constant_pool_reference(oop referrer, oop referree, jint index);
1950 static inline bool report_primitive_array_values(oop array);
1951 static inline bool report_string_value(oop str);
1952 static inline bool report_primitive_instance_field(oop o, jint index, address value, char type);
1953 static inline bool report_primitive_static_field(oop o, jint index, address value, char type);
1954 };
1955
1956 // statics
1957 int CallbackInvoker::_heap_walk_type;
1958 BasicHeapWalkContext CallbackInvoker::_basic_context;
1959 AdvancedHeapWalkContext CallbackInvoker::_advanced_context;
1960 JvmtiTagMap* CallbackInvoker::_tag_map;
1961 const void* CallbackInvoker::_user_data;
1962 GrowableArray<oop>* CallbackInvoker::_visit_stack;
1963
1964 // initialize for basic heap walk (IterateOverReachableObjects et al)
1965 void CallbackInvoker::initialize_for_basic_heap_walk(JvmtiTagMap* tag_map,
1966 GrowableArray<oop>* visit_stack,
1967 const void* user_data,
1968 BasicHeapWalkContext context) {
1969 _tag_map = tag_map;
1970 _visit_stack = visit_stack;
1971 _user_data = user_data;
1972 _basic_context = context;
1973 _advanced_context.invalidate(); // will trigger assertion if used
1974 _heap_walk_type = basic;
1975 }
1976
1977 // initialize for advanced heap walk (FollowReferences)
1978 void CallbackInvoker::initialize_for_advanced_heap_walk(JvmtiTagMap* tag_map,
1979 GrowableArray<oop>* visit_stack,
1980 const void* user_data,
1981 AdvancedHeapWalkContext context) {
1982 _tag_map = tag_map;
1983 _visit_stack = visit_stack;
1984 _user_data = user_data;
1985 _advanced_context = context;
1986 _basic_context.invalidate(); // will trigger assertion if used
1987 _heap_walk_type = advanced;
1988 }
1989
1990
1991 // invoke basic style heap root callback
1992 inline bool CallbackInvoker::invoke_basic_heap_root_callback(jvmtiHeapRootKind root_kind, oop obj) {
1993 // if we heap roots should be reported
1994 jvmtiHeapRootCallback cb = basic_context()->heap_root_callback();
1995 if (cb == NULL) {
1996 return check_for_visit(obj);
1997 }
1998
1999 CallbackWrapper wrapper(tag_map(), obj);
2000 jvmtiIterationControl control = (*cb)(root_kind,
2001 wrapper.klass_tag(),
2002 wrapper.obj_size(),
2003 wrapper.obj_tag_p(),
2004 (void*)user_data());
2005 // push root to visit stack when following references
2006 if (control == JVMTI_ITERATION_CONTINUE &&
2007 basic_context()->object_ref_callback() != NULL) {
2008 visit_stack()->push(obj);
2009 }
2010 return control != JVMTI_ITERATION_ABORT;
2011 }
2012
2013 // invoke basic style stack ref callback
2014 inline bool CallbackInvoker::invoke_basic_stack_ref_callback(jvmtiHeapRootKind root_kind,
2015 jlong thread_tag,
2016 jint depth,
2017 jmethodID method,
2018 int slot,
2019 oop obj) {
2020 // if we stack refs should be reported
2021 jvmtiStackReferenceCallback cb = basic_context()->stack_ref_callback();
2022 if (cb == NULL) {
2023 return check_for_visit(obj);
2024 }
2025
2026 CallbackWrapper wrapper(tag_map(), obj);
2027 jvmtiIterationControl control = (*cb)(root_kind,
2028 wrapper.klass_tag(),
2029 wrapper.obj_size(),
2030 wrapper.obj_tag_p(),
2031 thread_tag,
2032 depth,
2033 method,
2034 slot,
2035 (void*)user_data());
2036 // push root to visit stack when following references
2037 if (control == JVMTI_ITERATION_CONTINUE &&
2038 basic_context()->object_ref_callback() != NULL) {
2039 visit_stack()->push(obj);
2040 }
2041 return control != JVMTI_ITERATION_ABORT;
2042 }
2043
2044 // invoke basic style object reference callback
2045 inline bool CallbackInvoker::invoke_basic_object_reference_callback(jvmtiObjectReferenceKind ref_kind,
2046 oop referrer,
2047 oop referree,
2048 jint index) {
2049
2050 BasicHeapWalkContext* context = basic_context();
2051
2052 // callback requires the referrer's tag. If it's the same referrer
2053 // as the last call then we use the cached value.
2054 jlong referrer_tag;
2055 if (referrer == context->last_referrer()) {
2056 referrer_tag = context->last_referrer_tag();
2057 } else {
2058 referrer_tag = tag_for(tag_map(), referrer);
2059 }
2060
2061 // do the callback
2062 CallbackWrapper wrapper(tag_map(), referree);
2063 jvmtiObjectReferenceCallback cb = context->object_ref_callback();
2064 jvmtiIterationControl control = (*cb)(ref_kind,
2065 wrapper.klass_tag(),
2066 wrapper.obj_size(),
2067 wrapper.obj_tag_p(),
2068 referrer_tag,
2069 index,
2070 (void*)user_data());
2071
2072 // record referrer and referrer tag. For self-references record the
2073 // tag value from the callback as this might differ from referrer_tag.
2074 context->set_last_referrer(referrer);
2075 if (referrer == referree) {
2076 context->set_last_referrer_tag(*wrapper.obj_tag_p());
2077 } else {
2078 context->set_last_referrer_tag(referrer_tag);
2079 }
2080
2081 if (control == JVMTI_ITERATION_CONTINUE) {
2082 return check_for_visit(referree);
2083 } else {
2084 return control != JVMTI_ITERATION_ABORT;
2085 }
2086 }
2087
2088 // invoke advanced style heap root callback
2089 inline bool CallbackInvoker::invoke_advanced_heap_root_callback(jvmtiHeapReferenceKind ref_kind,
2090 oop obj) {
2091 AdvancedHeapWalkContext* context = advanced_context();
2092
2093 // check that callback is provided
2094 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
2095 if (cb == NULL) {
2096 return check_for_visit(obj);
2097 }
2098
2099 // apply class filter
2100 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2101 return check_for_visit(obj);
2102 }
2103
2104 // setup the callback wrapper
2105 CallbackWrapper wrapper(tag_map(), obj);
2106
2107 // apply tag filter
2108 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2109 wrapper.klass_tag(),
2110 context->heap_filter())) {
2111 return check_for_visit(obj);
2112 }
2113
2114 // for arrays we need the length, otherwise -1
2115 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
2116
2117 // invoke the callback
2118 jint res = (*cb)(ref_kind,
2119 NULL, // referrer info
2120 wrapper.klass_tag(),
2121 0, // referrer_class_tag is 0 for heap root
2122 wrapper.obj_size(),
2123 wrapper.obj_tag_p(),
2124 NULL, // referrer_tag_p
2125 len,
2126 (void*)user_data());
2127 if (res & JVMTI_VISIT_ABORT) {
2128 return false;// referrer class tag
2129 }
2130 if (res & JVMTI_VISIT_OBJECTS) {
2131 check_for_visit(obj);
2132 }
2133 return true;
2134 }
2135
2136 // report a reference from a thread stack to an object
2137 inline bool CallbackInvoker::invoke_advanced_stack_ref_callback(jvmtiHeapReferenceKind ref_kind,
2138 jlong thread_tag,
2139 jlong tid,
2140 int depth,
2141 jmethodID method,
2142 jlocation bci,
2143 jint slot,
2144 oop obj) {
2145 AdvancedHeapWalkContext* context = advanced_context();
2146
2147 // check that callback is provider
2148 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
2149 if (cb == NULL) {
2150 return check_for_visit(obj);
2151 }
2152
2153 // apply class filter
2154 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2155 return check_for_visit(obj);
2156 }
2157
2158 // setup the callback wrapper
2159 CallbackWrapper wrapper(tag_map(), obj);
2160
2161 // apply tag filter
2162 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2163 wrapper.klass_tag(),
2164 context->heap_filter())) {
2165 return check_for_visit(obj);
2166 }
2167
2168 // setup the referrer info
2169 jvmtiHeapReferenceInfo reference_info;
2170 reference_info.stack_local.thread_tag = thread_tag;
2171 reference_info.stack_local.thread_id = tid;
2172 reference_info.stack_local.depth = depth;
2173 reference_info.stack_local.method = method;
2174 reference_info.stack_local.location = bci;
2175 reference_info.stack_local.slot = slot;
2176
2177 // for arrays we need the length, otherwise -1
2178 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
2179
2180 // call into the agent
2181 int res = (*cb)(ref_kind,
2182 &reference_info,
2183 wrapper.klass_tag(),
2184 0, // referrer_class_tag is 0 for heap root (stack)
2185 wrapper.obj_size(),
2186 wrapper.obj_tag_p(),
2187 NULL, // referrer_tag is 0 for root
2188 len,
2189 (void*)user_data());
2190
2191 if (res & JVMTI_VISIT_ABORT) {
2192 return false;
2193 }
2194 if (res & JVMTI_VISIT_OBJECTS) {
2195 check_for_visit(obj);
2196 }
2197 return true;
2198 }
2199
2200 // This mask is used to pass reference_info to a jvmtiHeapReferenceCallback
2201 // only for ref_kinds defined by the JVM TI spec. Otherwise, NULL is passed.
2202 #define REF_INFO_MASK ((1 << JVMTI_HEAP_REFERENCE_FIELD) \
2203 | (1 << JVMTI_HEAP_REFERENCE_STATIC_FIELD) \
2204 | (1 << JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT) \
2205 | (1 << JVMTI_HEAP_REFERENCE_CONSTANT_POOL) \
2206 | (1 << JVMTI_HEAP_REFERENCE_STACK_LOCAL) \
2207 | (1 << JVMTI_HEAP_REFERENCE_JNI_LOCAL))
2208
2209 // invoke the object reference callback to report a reference
2210 inline bool CallbackInvoker::invoke_advanced_object_reference_callback(jvmtiHeapReferenceKind ref_kind,
2211 oop referrer,
2212 oop obj,
2213 jint index)
2214 {
2215 // field index is only valid field in reference_info
2216 static jvmtiHeapReferenceInfo reference_info = { 0 };
2217
2218 AdvancedHeapWalkContext* context = advanced_context();
2219
2220 // check that callback is provider
2221 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
2222 if (cb == NULL) {
2223 return check_for_visit(obj);
2224 }
2225
2226 // apply class filter
2227 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2228 return check_for_visit(obj);
2229 }
2230
2231 // setup the callback wrapper
2232 TwoOopCallbackWrapper wrapper(tag_map(), referrer, obj);
2233
2234 // apply tag filter
2235 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2236 wrapper.klass_tag(),
2237 context->heap_filter())) {
2238 return check_for_visit(obj);
2239 }
2240
2241 // field index is only valid field in reference_info
2242 reference_info.field.index = index;
2243
2244 // for arrays we need the length, otherwise -1
2245 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
2246
2247 // invoke the callback
2248 int res = (*cb)(ref_kind,
2249 (REF_INFO_MASK & (1 << ref_kind)) ? &reference_info : NULL,
2250 wrapper.klass_tag(),
2251 wrapper.referrer_klass_tag(),
2252 wrapper.obj_size(),
2253 wrapper.obj_tag_p(),
2254 wrapper.referrer_tag_p(),
2255 len,
2256 (void*)user_data());
2257
2258 if (res & JVMTI_VISIT_ABORT) {
2259 return false;
2260 }
2261 if (res & JVMTI_VISIT_OBJECTS) {
2262 check_for_visit(obj);
2263 }
2264 return true;
2265 }
2266
2267 // report a "simple root"
2268 inline bool CallbackInvoker::report_simple_root(jvmtiHeapReferenceKind kind, oop obj) {
2269 assert(kind != JVMTI_HEAP_REFERENCE_STACK_LOCAL &&
2270 kind != JVMTI_HEAP_REFERENCE_JNI_LOCAL, "not a simple root");
2271
2272 if (is_basic_heap_walk()) {
2273 // map to old style root kind
2274 jvmtiHeapRootKind root_kind = toJvmtiHeapRootKind(kind);
2275 return invoke_basic_heap_root_callback(root_kind, obj);
2276 } else {
2277 assert(is_advanced_heap_walk(), "wrong heap walk type");
2278 return invoke_advanced_heap_root_callback(kind, obj);
2279 }
2280 }
2281
2282
2283 // invoke the primitive array values
2284 inline bool CallbackInvoker::report_primitive_array_values(oop obj) {
2285 assert(obj->is_typeArray(), "not a primitive array");
2286
2287 AdvancedHeapWalkContext* context = advanced_context();
2288 assert(context->array_primitive_value_callback() != NULL, "no callback");
2289
2290 // apply class filter
2291 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2292 return true;
2293 }
2294
2295 CallbackWrapper wrapper(tag_map(), obj);
2296
2297 // apply tag filter
2298 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2299 wrapper.klass_tag(),
2300 context->heap_filter())) {
2301 return true;
2302 }
2303
2304 // invoke the callback
2305 int res = invoke_array_primitive_value_callback(context->array_primitive_value_callback(),
2306 &wrapper,
2307 obj,
2308 (void*)user_data());
2309 return (!(res & JVMTI_VISIT_ABORT));
2310 }
2311
2312 // invoke the string value callback
2313 inline bool CallbackInvoker::report_string_value(oop str) {
2314 assert(str->klass() == SystemDictionary::String_klass(), "not a string");
2315
2316 AdvancedHeapWalkContext* context = advanced_context();
2317 assert(context->string_primitive_value_callback() != NULL, "no callback");
2318
2319 // apply class filter
2320 if (is_filtered_by_klass_filter(str, context->klass_filter())) {
2321 return true;
2322 }
2323
2324 CallbackWrapper wrapper(tag_map(), str);
2325
2326 // apply tag filter
2327 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2328 wrapper.klass_tag(),
2329 context->heap_filter())) {
2330 return true;
2331 }
2332
2333 // invoke the callback
2334 int res = invoke_string_value_callback(context->string_primitive_value_callback(),
2335 &wrapper,
2336 str,
2337 (void*)user_data());
2338 return (!(res & JVMTI_VISIT_ABORT));
2339 }
2340
2341 // invoke the primitive field callback
2342 inline bool CallbackInvoker::report_primitive_field(jvmtiHeapReferenceKind ref_kind,
2343 oop obj,
2344 jint index,
2345 address addr,
2346 char type)
2347 {
2348 // for primitive fields only the index will be set
2349 static jvmtiHeapReferenceInfo reference_info = { 0 };
2350
2351 AdvancedHeapWalkContext* context = advanced_context();
2352 assert(context->primitive_field_callback() != NULL, "no callback");
2353
2354 // apply class filter
2355 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2356 return true;
2357 }
2358
2359 CallbackWrapper wrapper(tag_map(), obj);
2360
2361 // apply tag filter
2362 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2363 wrapper.klass_tag(),
2364 context->heap_filter())) {
2365 return true;
2366 }
2367
2368 // the field index in the referrer
2369 reference_info.field.index = index;
2370
2371 // map the type
2372 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
2373
2374 // setup the jvalue
2375 jvalue value;
2376 copy_to_jvalue(&value, addr, value_type);
2377
2378 jvmtiPrimitiveFieldCallback cb = context->primitive_field_callback();
2379 int res = (*cb)(ref_kind,
2380 &reference_info,
2381 wrapper.klass_tag(),
2382 wrapper.obj_tag_p(),
2383 value,
2384 value_type,
2385 (void*)user_data());
2386 return (!(res & JVMTI_VISIT_ABORT));
2387 }
2388
2389
2390 // instance field
2391 inline bool CallbackInvoker::report_primitive_instance_field(oop obj,
2392 jint index,
2393 address value,
2394 char type) {
2395 return report_primitive_field(JVMTI_HEAP_REFERENCE_FIELD,
2396 obj,
2397 index,
2398 value,
2399 type);
2400 }
2401
2402 // static field
2403 inline bool CallbackInvoker::report_primitive_static_field(oop obj,
2404 jint index,
2405 address value,
2406 char type) {
2407 return report_primitive_field(JVMTI_HEAP_REFERENCE_STATIC_FIELD,
2408 obj,
2409 index,
2410 value,
2411 type);
2412 }
2413
2414 // report a JNI local (root object) to the profiler
2415 inline bool CallbackInvoker::report_jni_local_root(jlong thread_tag, jlong tid, jint depth, jmethodID m, oop obj) {
2416 if (is_basic_heap_walk()) {
2417 return invoke_basic_stack_ref_callback(JVMTI_HEAP_ROOT_JNI_LOCAL,
2418 thread_tag,
2419 depth,
2420 m,
2421 -1,
2422 obj);
2423 } else {
2424 return invoke_advanced_stack_ref_callback(JVMTI_HEAP_REFERENCE_JNI_LOCAL,
2425 thread_tag, tid,
2426 depth,
2427 m,
2428 (jlocation)-1,
2429 -1,
2430 obj);
2431 }
2432 }
2433
2434
2435 // report a local (stack reference, root object)
2436 inline bool CallbackInvoker::report_stack_ref_root(jlong thread_tag,
2437 jlong tid,
2438 jint depth,
2439 jmethodID method,
2440 jlocation bci,
2441 jint slot,
2442 oop obj) {
2443 if (is_basic_heap_walk()) {
2444 return invoke_basic_stack_ref_callback(JVMTI_HEAP_ROOT_STACK_LOCAL,
2445 thread_tag,
2446 depth,
2447 method,
2448 slot,
2449 obj);
2450 } else {
2451 return invoke_advanced_stack_ref_callback(JVMTI_HEAP_REFERENCE_STACK_LOCAL,
2452 thread_tag,
2453 tid,
2454 depth,
2455 method,
2456 bci,
2457 slot,
2458 obj);
2459 }
2460 }
2461
2462 // report an object referencing a class.
2463 inline bool CallbackInvoker::report_class_reference(oop referrer, oop referree) {
2464 if (is_basic_heap_walk()) {
2465 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS, referrer, referree, -1);
2466 } else {
2467 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CLASS, referrer, referree, -1);
2468 }
2469 }
2470
2471 // report a class referencing its class loader.
2472 inline bool CallbackInvoker::report_class_loader_reference(oop referrer, oop referree) {
2473 if (is_basic_heap_walk()) {
2474 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS_LOADER, referrer, referree, -1);
2475 } else {
2476 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CLASS_LOADER, referrer, referree, -1);
2477 }
2478 }
2479
2480 // report a class referencing its signers.
2481 inline bool CallbackInvoker::report_signers_reference(oop referrer, oop referree) {
2482 if (is_basic_heap_walk()) {
2483 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_SIGNERS, referrer, referree, -1);
2484 } else {
2485 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_SIGNERS, referrer, referree, -1);
2486 }
2487 }
2488
2489 // report a class referencing its protection domain..
2490 inline bool CallbackInvoker::report_protection_domain_reference(oop referrer, oop referree) {
2491 if (is_basic_heap_walk()) {
2492 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_PROTECTION_DOMAIN, referrer, referree, -1);
2493 } else {
2494 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_PROTECTION_DOMAIN, referrer, referree, -1);
2495 }
2496 }
2497
2498 // report a class referencing its superclass.
2499 inline bool CallbackInvoker::report_superclass_reference(oop referrer, oop referree) {
2500 if (is_basic_heap_walk()) {
2501 // Send this to be consistent with past implementation
2502 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS, referrer, referree, -1);
2503 } else {
2504 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_SUPERCLASS, referrer, referree, -1);
2505 }
2506 }
2507
2508 // report a class referencing one of its interfaces.
2509 inline bool CallbackInvoker::report_interface_reference(oop referrer, oop referree) {
2510 if (is_basic_heap_walk()) {
2511 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_INTERFACE, referrer, referree, -1);
2512 } else {
2513 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_INTERFACE, referrer, referree, -1);
2514 }
2515 }
2516
2517 // report a class referencing one of its static fields.
2518 inline bool CallbackInvoker::report_static_field_reference(oop referrer, oop referree, jint slot) {
2519 if (is_basic_heap_walk()) {
2520 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_STATIC_FIELD, referrer, referree, slot);
2521 } else {
2522 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_STATIC_FIELD, referrer, referree, slot);
2523 }
2524 }
2525
2526 // report an array referencing an element object
2527 inline bool CallbackInvoker::report_array_element_reference(oop referrer, oop referree, jint index) {
2528 if (is_basic_heap_walk()) {
2529 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_ARRAY_ELEMENT, referrer, referree, index);
2530 } else {
2531 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT, referrer, referree, index);
2532 }
2533 }
2534
2535 // report an object referencing an instance field object
2536 inline bool CallbackInvoker::report_field_reference(oop referrer, oop referree, jint slot) {
2537 if (is_basic_heap_walk()) {
2538 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_FIELD, referrer, referree, slot);
2539 } else {
2540 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_FIELD, referrer, referree, slot);
2541 }
2542 }
2543
2544 // report an array referencing an element object
2545 inline bool CallbackInvoker::report_constant_pool_reference(oop referrer, oop referree, jint index) {
2546 if (is_basic_heap_walk()) {
2547 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CONSTANT_POOL, referrer, referree, index);
2548 } else {
2549 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CONSTANT_POOL, referrer, referree, index);
2550 }
2551 }
2552
2553 // A supporting closure used to process simple roots
2554 class SimpleRootsClosure : public OopClosure {
2555 private:
2556 jvmtiHeapReferenceKind _kind;
2557 bool _continue;
2558
2559 jvmtiHeapReferenceKind root_kind() { return _kind; }
2560
2561 public:
2562 void set_kind(jvmtiHeapReferenceKind kind) {
2563 _kind = kind;
2564 _continue = true;
2565 }
2566
2567 inline bool stopped() {
2568 return !_continue;
2569 }
2570
2571 void do_oop(oop* obj_p) {
2572 // iteration has terminated
2573 if (stopped()) {
2574 return;
2575 }
2576
2577 oop o = NativeAccess<AS_NO_KEEPALIVE>::oop_load(obj_p);
2578 // ignore null
2579 if (o == NULL) {
2580 return;
2581 }
2582
2583 assert(Universe::heap()->is_in_reserved(o), "should be impossible");
2584
2585 jvmtiHeapReferenceKind kind = root_kind();
2586 if (kind == JVMTI_HEAP_REFERENCE_SYSTEM_CLASS) {
2587 // SystemDictionary::oops_do reports the application
2588 // class loader as a root. We want this root to be reported as
2589 // a root kind of "OTHER" rather than "SYSTEM_CLASS".
2590 if (!o->is_instance() || !InstanceKlass::cast(o->klass())->is_mirror_instance_klass()) {
2591 kind = JVMTI_HEAP_REFERENCE_OTHER;
2592 }
2593 }
2594
2595 // invoke the callback
2596 _continue = CallbackInvoker::report_simple_root(kind, o);
2597
2598 }
2599 virtual void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
2600 };
2601
2602 // A supporting closure used to process JNI locals
2603 class JNILocalRootsClosure : public OopClosure {
2604 private:
2605 jlong _thread_tag;
2606 jlong _tid;
2607 jint _depth;
2608 jmethodID _method;
2609 bool _continue;
2610 public:
2611 void set_context(jlong thread_tag, jlong tid, jint depth, jmethodID method) {
2612 _thread_tag = thread_tag;
2613 _tid = tid;
2614 _depth = depth;
2615 _method = method;
2616 _continue = true;
2617 }
2618
2619 inline bool stopped() {
2620 return !_continue;
2621 }
2622
2623 void do_oop(oop* obj_p) {
2624 // iteration has terminated
2625 if (stopped()) {
2626 return;
2627 }
2628
2629 oop o = *obj_p;
2630 // ignore null
2631 if (o == NULL) {
2632 return;
2633 }
2634
2635 // invoke the callback
2636 _continue = CallbackInvoker::report_jni_local_root(_thread_tag, _tid, _depth, _method, o);
2637 }
2638 virtual void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
2639 };
2640
2641
2642 // A VM operation to iterate over objects that are reachable from
2643 // a set of roots or an initial object.
2644 //
2645 // For VM_HeapWalkOperation the set of roots used is :-
2646 //
2647 // - All JNI global references
2648 // - All inflated monitors
2649 // - All classes loaded by the boot class loader (or all classes
2650 // in the event that class unloading is disabled)
2651 // - All java threads
2652 // - For each java thread then all locals and JNI local references
2653 // on the thread's execution stack
2654 // - All visible/explainable objects from Universes::oops_do
2655 //
2656 class VM_HeapWalkOperation: public VM_Operation {
2657 private:
2658 enum {
2659 initial_visit_stack_size = 4000
2660 };
2661
2662 bool _is_advanced_heap_walk; // indicates FollowReferences
2663 JvmtiTagMap* _tag_map;
2664 Handle _initial_object;
2665 GrowableArray<oop>* _visit_stack; // the visit stack
2666
2667 bool _collecting_heap_roots; // are we collecting roots
2668 bool _following_object_refs; // are we following object references
2669
2670 bool _reporting_primitive_fields; // optional reporting
2671 bool _reporting_primitive_array_values;
2672 bool _reporting_string_values;
2673
2674 GrowableArray<oop>* create_visit_stack() {
2675 return new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(initial_visit_stack_size, true);
2676 }
2677
2678 // accessors
2679 bool is_advanced_heap_walk() const { return _is_advanced_heap_walk; }
2680 JvmtiTagMap* tag_map() const { return _tag_map; }
2681 Handle initial_object() const { return _initial_object; }
2682
2683 bool is_following_references() const { return _following_object_refs; }
2684
2685 bool is_reporting_primitive_fields() const { return _reporting_primitive_fields; }
2686 bool is_reporting_primitive_array_values() const { return _reporting_primitive_array_values; }
2687 bool is_reporting_string_values() const { return _reporting_string_values; }
2688
2689 GrowableArray<oop>* visit_stack() const { return _visit_stack; }
2690
2691 // iterate over the various object types
2692 inline bool iterate_over_array(oop o);
2693 inline bool iterate_over_type_array(oop o);
2694 inline bool iterate_over_class(oop o);
2695 inline bool iterate_over_object(oop o);
2696
2697 // root collection
2698 inline bool collect_simple_roots();
2699 inline bool collect_stack_roots();
2700 inline bool collect_stack_roots(JavaThread* java_thread, JNILocalRootsClosure* blk);
2701
2702 // visit an object
2703 inline bool visit(oop o);
2704
2705 public:
2706 VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2707 Handle initial_object,
2708 BasicHeapWalkContext callbacks,
2709 const void* user_data);
2710
2711 VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2712 Handle initial_object,
2713 AdvancedHeapWalkContext callbacks,
2714 const void* user_data);
2715
2716 ~VM_HeapWalkOperation();
2717
2718 VMOp_Type type() const { return VMOp_HeapWalkOperation; }
2719 void doit();
2720 };
2721
2722
2723 VM_HeapWalkOperation::VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2724 Handle initial_object,
2725 BasicHeapWalkContext callbacks,
2726 const void* user_data) {
2727 _is_advanced_heap_walk = false;
2728 _tag_map = tag_map;
2729 _initial_object = initial_object;
2730 _following_object_refs = (callbacks.object_ref_callback() != NULL);
2731 _reporting_primitive_fields = false;
2732 _reporting_primitive_array_values = false;
2733 _reporting_string_values = false;
2734 _visit_stack = create_visit_stack();
2735
2736
2737 CallbackInvoker::initialize_for_basic_heap_walk(tag_map, _visit_stack, user_data, callbacks);
2738 }
2739
2740 VM_HeapWalkOperation::VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2741 Handle initial_object,
2742 AdvancedHeapWalkContext callbacks,
2743 const void* user_data) {
2744 _is_advanced_heap_walk = true;
2745 _tag_map = tag_map;
2746 _initial_object = initial_object;
2747 _following_object_refs = true;
2748 _reporting_primitive_fields = (callbacks.primitive_field_callback() != NULL);;
2749 _reporting_primitive_array_values = (callbacks.array_primitive_value_callback() != NULL);;
2750 _reporting_string_values = (callbacks.string_primitive_value_callback() != NULL);;
2751 _visit_stack = create_visit_stack();
2752
2753 CallbackInvoker::initialize_for_advanced_heap_walk(tag_map, _visit_stack, user_data, callbacks);
2754 }
2755
2756 VM_HeapWalkOperation::~VM_HeapWalkOperation() {
2757 if (_following_object_refs) {
2758 assert(_visit_stack != NULL, "checking");
2759 delete _visit_stack;
2760 _visit_stack = NULL;
2761 }
2762 }
2763
2764 // an array references its class and has a reference to
2765 // each element in the array
2766 inline bool VM_HeapWalkOperation::iterate_over_array(oop o) {
2767 objArrayOop array = objArrayOop(o);
2768
2769 // array reference to its class
2770 oop mirror = ObjArrayKlass::cast(array->klass())->java_mirror();
2771 if (!CallbackInvoker::report_class_reference(o, mirror)) {
2772 return false;
2773 }
2774
2775 // iterate over the array and report each reference to a
2776 // non-null element
2777 for (int index=0; index<array->length(); index++) {
2778 oop elem = array->obj_at(index);
2779 if (elem == NULL) {
2780 continue;
2781 }
2782
2783 // report the array reference o[index] = elem
2784 if (!CallbackInvoker::report_array_element_reference(o, elem, index)) {
2785 return false;
2786 }
2787 }
2788 return true;
2789 }
2790
2791 // a type array references its class
2792 inline bool VM_HeapWalkOperation::iterate_over_type_array(oop o) {
2793 Klass* k = o->klass();
2794 oop mirror = k->java_mirror();
2795 if (!CallbackInvoker::report_class_reference(o, mirror)) {
2796 return false;
2797 }
2798
2799 // report the array contents if required
2800 if (is_reporting_primitive_array_values()) {
2801 if (!CallbackInvoker::report_primitive_array_values(o)) {
2802 return false;
2803 }
2804 }
2805 return true;
2806 }
2807
2808 #ifdef ASSERT
2809 // verify that a static oop field is in range
2810 static inline bool verify_static_oop(InstanceKlass* ik,
2811 oop mirror, int offset) {
2812 address obj_p = (address)mirror + offset;
2813 address start = (address)InstanceMirrorKlass::start_of_static_fields(mirror);
2814 address end = start + (java_lang_Class::static_oop_field_count(mirror) * heapOopSize);
2815 assert(end >= start, "sanity check");
2816
2817 if (obj_p >= start && obj_p < end) {
2818 return true;
2819 } else {
2820 return false;
2821 }
2822 }
2823 #endif // #ifdef ASSERT
2824
2825 // a class references its super class, interfaces, class loader, ...
2826 // and finally its static fields
2827 inline bool VM_HeapWalkOperation::iterate_over_class(oop java_class) {
2828 int i;
2829 Klass* klass = java_lang_Class::as_Klass(java_class);
2830
2831 if (klass->is_instance_klass()) {
2832 InstanceKlass* ik = InstanceKlass::cast(klass);
2833
2834 // Ignore the class if it hasn't been initialized yet
2835 if (!ik->is_linked()) {
2836 return true;
2837 }
2838
2839 // get the java mirror
2840 oop mirror = klass->java_mirror();
2841
2842 // super (only if something more interesting than java.lang.Object)
2843 InstanceKlass* java_super = ik->java_super();
2844 if (java_super != NULL && java_super != SystemDictionary::Object_klass()) {
2845 oop super = java_super->java_mirror();
2846 if (!CallbackInvoker::report_superclass_reference(mirror, super)) {
2847 return false;
2848 }
2849 }
2850
2851 // class loader
2852 oop cl = ik->class_loader();
2853 if (cl != NULL) {
2854 if (!CallbackInvoker::report_class_loader_reference(mirror, cl)) {
2855 return false;
2856 }
2857 }
2858
2859 // protection domain
2860 oop pd = ik->protection_domain();
2861 if (pd != NULL) {
2862 if (!CallbackInvoker::report_protection_domain_reference(mirror, pd)) {
2863 return false;
2864 }
2865 }
2866
2867 // signers
2868 oop signers = ik->signers();
2869 if (signers != NULL) {
2870 if (!CallbackInvoker::report_signers_reference(mirror, signers)) {
2871 return false;
2872 }
2873 }
2874
2875 // references from the constant pool
2876 {
2877 ConstantPool* pool = ik->constants();
2878 for (int i = 1; i < pool->length(); i++) {
2879 constantTag tag = pool->tag_at(i).value();
2880 if (tag.is_string() || tag.is_klass() || tag.is_unresolved_klass()) {
2881 oop entry;
2882 if (tag.is_string()) {
2883 entry = pool->resolved_string_at(i);
2884 // If the entry is non-null it is resolved.
2885 if (entry == NULL) {
2886 continue;
2887 }
2888 } else if (tag.is_klass()) {
2889 entry = pool->resolved_klass_at(i)->java_mirror();
2890 } else {
2891 // Code generated by JIT and AOT compilers might not resolve constant
2892 // pool entries. Treat them as resolved if they are loaded.
2893 assert(tag.is_unresolved_klass(), "must be");
2894 constantPoolHandle cp(Thread::current(), pool);
2895 Klass* klass = ConstantPool::klass_at_if_loaded(cp, i);
2896 if (klass == NULL) {
2897 continue;
2898 }
2899 entry = klass->java_mirror();
2900 }
2901 if (!CallbackInvoker::report_constant_pool_reference(mirror, entry, (jint)i)) {
2902 return false;
2903 }
2904 }
2905 }
2906 }
2907
2908 // interfaces
2909 // (These will already have been reported as references from the constant pool
2910 // but are specified by IterateOverReachableObjects and must be reported).
2911 Array<InstanceKlass*>* interfaces = ik->local_interfaces();
2912 for (i = 0; i < interfaces->length(); i++) {
2913 oop interf = interfaces->at(i)->java_mirror();
2914 if (interf == NULL) {
2915 continue;
2916 }
2917 if (!CallbackInvoker::report_interface_reference(mirror, interf)) {
2918 return false;
2919 }
2920 }
2921
2922 // iterate over the static fields
2923
2924 ClassFieldMap* field_map = ClassFieldMap::create_map_of_static_fields(klass);
2925 for (i=0; i<field_map->field_count(); i++) {
2926 ClassFieldDescriptor* field = field_map->field_at(i);
2927 char type = field->field_type();
2928 if (!is_primitive_field_type(type)) {
2929 oop fld_o = mirror->obj_field(field->field_offset());
2930 assert(verify_static_oop(ik, mirror, field->field_offset()), "sanity check");
2931 if (fld_o != NULL) {
2932 int slot = field->field_index();
2933 if (!CallbackInvoker::report_static_field_reference(mirror, fld_o, slot)) {
2934 delete field_map;
2935 return false;
2936 }
2937 }
2938 } else {
2939 if (is_reporting_primitive_fields()) {
2940 address addr = (address)mirror + field->field_offset();
2941 int slot = field->field_index();
2942 if (!CallbackInvoker::report_primitive_static_field(mirror, slot, addr, type)) {
2943 delete field_map;
2944 return false;
2945 }
2946 }
2947 }
2948 }
2949 delete field_map;
2950
2951 return true;
2952 }
2953
2954 return true;
2955 }
2956
2957 // an object references a class and its instance fields
2958 // (static fields are ignored here as we report these as
2959 // references from the class).
2960 inline bool VM_HeapWalkOperation::iterate_over_object(oop o) {
2961 // reference to the class
2962 if (!CallbackInvoker::report_class_reference(o, o->klass()->java_mirror())) {
2963 return false;
2964 }
2965
2966 // iterate over instance fields
2967 ClassFieldMap* field_map = JvmtiCachedClassFieldMap::get_map_of_instance_fields(o);
2968 for (int i=0; i<field_map->field_count(); i++) {
2969 ClassFieldDescriptor* field = field_map->field_at(i);
2970 char type = field->field_type();
2971 if (!is_primitive_field_type(type)) {
2972 oop fld_o = o->obj_field(field->field_offset());
2973 // ignore any objects that aren't visible to profiler
2974 if (fld_o != NULL) {
2975 assert(Universe::heap()->is_in_reserved(fld_o), "unsafe code should not "
2976 "have references to Klass* anymore");
2977 int slot = field->field_index();
2978 if (!CallbackInvoker::report_field_reference(o, fld_o, slot)) {
2979 return false;
2980 }
2981 }
2982 } else {
2983 if (is_reporting_primitive_fields()) {
2984 // primitive instance field
2985 address addr = (address)o + field->field_offset();
2986 int slot = field->field_index();
2987 if (!CallbackInvoker::report_primitive_instance_field(o, slot, addr, type)) {
2988 return false;
2989 }
2990 }
2991 }
2992 }
2993
2994 // if the object is a java.lang.String
2995 if (is_reporting_string_values() &&
2996 o->klass() == SystemDictionary::String_klass()) {
2997 if (!CallbackInvoker::report_string_value(o)) {
2998 return false;
2999 }
3000 }
3001 return true;
3002 }
3003
3004
3005 // Collects all simple (non-stack) roots except for threads;
3006 // threads are handled in collect_stack_roots() as an optimization.
3007 // if there's a heap root callback provided then the callback is
3008 // invoked for each simple root.
3009 // if an object reference callback is provided then all simple
3010 // roots are pushed onto the marking stack so that they can be
3011 // processed later
3012 //
3013 inline bool VM_HeapWalkOperation::collect_simple_roots() {
3014 SimpleRootsClosure blk;
3015
3016 // JNI globals
3017 blk.set_kind(JVMTI_HEAP_REFERENCE_JNI_GLOBAL);
3018 JNIHandles::oops_do(&blk);
3019 if (blk.stopped()) {
3020 return false;
3021 }
3022
3023 // Preloaded classes and loader from the system dictionary
3024 blk.set_kind(JVMTI_HEAP_REFERENCE_SYSTEM_CLASS);
3025 SystemDictionary::oops_do(&blk);
3026 CLDToOopClosure cld_closure(&blk, false);
3027 ClassLoaderDataGraph::always_strong_cld_do(&cld_closure);
3028 if (blk.stopped()) {
3029 return false;
3030 }
3031
3032 // Inflated monitors
3033 blk.set_kind(JVMTI_HEAP_REFERENCE_MONITOR);
3034 ObjectSynchronizer::oops_do(&blk);
3035 if (blk.stopped()) {
3036 return false;
3037 }
3038
3039 // threads are now handled in collect_stack_roots()
3040
3041 // Other kinds of roots maintained by HotSpot
3042 // Many of these won't be visible but others (such as instances of important
3043 // exceptions) will be visible.
3044 blk.set_kind(JVMTI_HEAP_REFERENCE_OTHER);
3045 Universe::oops_do(&blk);
3046 if (blk.stopped()) {
3047 return false;
3048 }
3049
3050 return true;
3051 }
3052
3053 // Walk the stack of a given thread and find all references (locals
3054 // and JNI calls) and report these as stack references
3055 inline bool VM_HeapWalkOperation::collect_stack_roots(JavaThread* java_thread,
3056 JNILocalRootsClosure* blk)
3057 {
3058 oop threadObj = java_thread->threadObj();
3059 assert(threadObj != NULL, "sanity check");
3060
3061 // only need to get the thread's tag once per thread
3062 jlong thread_tag = tag_for(_tag_map, threadObj);
3063
3064 // also need the thread id
3065 jlong tid = java_lang_Thread::thread_id(threadObj);
3066
3067
3068 if (java_thread->has_last_Java_frame()) {
3069
3070 // vframes are resource allocated
3071 Thread* current_thread = Thread::current();
3072 ResourceMark rm(current_thread);
3073 HandleMark hm(current_thread);
3074
3075 RegisterMap reg_map(java_thread);
3076 frame f = java_thread->last_frame();
3077 vframe* vf = vframe::new_vframe(&f, ®_map, java_thread);
3078
3079 bool is_top_frame = true;
3080 int depth = 0;
3081 frame* last_entry_frame = NULL;
3082
3083 while (vf != NULL) {
3084 if (vf->is_java_frame()) {
3085
3086 // java frame (interpreted, compiled, ...)
3087 javaVFrame *jvf = javaVFrame::cast(vf);
3088
3089 // the jmethodID
3090 jmethodID method = jvf->method()->jmethod_id();
3091
3092 if (!(jvf->method()->is_native())) {
3093 jlocation bci = (jlocation)jvf->bci();
3094 StackValueCollection* locals = jvf->locals();
3095 for (int slot=0; slot<locals->size(); slot++) {
3096 if (locals->at(slot)->type() == T_OBJECT) {
3097 oop o = locals->obj_at(slot)();
3098 if (o == NULL) {
3099 continue;
3100 }
3101
3102 // stack reference
3103 if (!CallbackInvoker::report_stack_ref_root(thread_tag, tid, depth, method,
3104 bci, slot, o)) {
3105 return false;
3106 }
3107 }
3108 }
3109
3110 StackValueCollection* exprs = jvf->expressions();
3111 for (int index=0; index < exprs->size(); index++) {
3112 if (exprs->at(index)->type() == T_OBJECT) {
3113 oop o = exprs->obj_at(index)();
3114 if (o == NULL) {
3115 continue;
3116 }
3117
3118 // stack reference
3119 if (!CallbackInvoker::report_stack_ref_root(thread_tag, tid, depth, method,
3120 bci, locals->size() + index, o)) {
3121 return false;
3122 }
3123 }
3124 }
3125
3126 // Follow oops from compiled nmethod
3127 if (jvf->cb() != NULL && jvf->cb()->is_nmethod()) {
3128 blk->set_context(thread_tag, tid, depth, method);
3129 jvf->cb()->as_nmethod()->oops_do(blk);
3130 }
3131 } else {
3132 blk->set_context(thread_tag, tid, depth, method);
3133 if (is_top_frame) {
3134 // JNI locals for the top frame.
3135 java_thread->active_handles()->oops_do(blk);
3136 } else {
3137 if (last_entry_frame != NULL) {
3138 // JNI locals for the entry frame
3139 assert(last_entry_frame->is_entry_frame(), "checking");
3140 last_entry_frame->entry_frame_call_wrapper()->handles()->oops_do(blk);
3141 }
3142 }
3143 }
3144 last_entry_frame = NULL;
3145 depth++;
3146 } else {
3147 // externalVFrame - for an entry frame then we report the JNI locals
3148 // when we find the corresponding javaVFrame
3149 frame* fr = vf->frame_pointer();
3150 assert(fr != NULL, "sanity check");
3151 if (fr->is_entry_frame()) {
3152 last_entry_frame = fr;
3153 }
3154 }
3155
3156 vf = vf->sender();
3157 is_top_frame = false;
3158 }
3159 } else {
3160 // no last java frame but there may be JNI locals
3161 blk->set_context(thread_tag, tid, 0, (jmethodID)NULL);
3162 java_thread->active_handles()->oops_do(blk);
3163 }
3164 return true;
3165 }
3166
3167
3168 // Collects the simple roots for all threads and collects all
3169 // stack roots - for each thread it walks the execution
3170 // stack to find all references and local JNI refs.
3171 inline bool VM_HeapWalkOperation::collect_stack_roots() {
3172 JNILocalRootsClosure blk;
3173 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) {
3174 oop threadObj = thread->threadObj();
3175 if (threadObj != NULL && !thread->is_exiting() && !thread->is_hidden_from_external_view()) {
3176 // Collect the simple root for this thread before we
3177 // collect its stack roots
3178 if (!CallbackInvoker::report_simple_root(JVMTI_HEAP_REFERENCE_THREAD,
3179 threadObj)) {
3180 return false;
3181 }
3182 if (!collect_stack_roots(thread, &blk)) {
3183 return false;
3184 }
3185 }
3186 }
3187 return true;
3188 }
3189
3190 // visit an object
3191 // first mark the object as visited
3192 // second get all the outbound references from this object (in other words, all
3193 // the objects referenced by this object).
3194 //
3195 bool VM_HeapWalkOperation::visit(oop o) {
3196 // mark object as visited
3197 assert(!ObjectMarker::visited(o), "can't visit same object more than once");
3198 ObjectMarker::mark(o);
3199
3200 // instance
3201 if (o->is_instance()) {
3202 if (o->klass() == SystemDictionary::Class_klass()) {
3203 if (!java_lang_Class::is_primitive(o)) {
3204 // a java.lang.Class
3205 return iterate_over_class(o);
3206 }
3207 } else {
3208 return iterate_over_object(o);
3209 }
3210 }
3211
3212 // object array
3213 if (o->is_objArray()) {
3214 return iterate_over_array(o);
3215 }
3216
3217 // type array
3218 if (o->is_typeArray()) {
3219 return iterate_over_type_array(o);
3220 }
3221
3222 return true;
3223 }
3224
3225 void VM_HeapWalkOperation::doit() {
3226 ResourceMark rm;
3227 ObjectMarkerController marker;
3228 ClassFieldMapCacheMark cm;
3229
3230 assert(visit_stack()->is_empty(), "visit stack must be empty");
3231
3232 // the heap walk starts with an initial object or the heap roots
3233 if (initial_object().is_null()) {
3234 // If either collect_stack_roots() or collect_simple_roots()
3235 // returns false at this point, then there are no mark bits
3236 // to reset.
3237 ObjectMarker::set_needs_reset(false);
3238
3239 // Calling collect_stack_roots() before collect_simple_roots()
3240 // can result in a big performance boost for an agent that is
3241 // focused on analyzing references in the thread stacks.
3242 if (!collect_stack_roots()) return;
3243
3244 if (!collect_simple_roots()) return;
3245
3246 // no early return so enable heap traversal to reset the mark bits
3247 ObjectMarker::set_needs_reset(true);
3248 } else {
3249 visit_stack()->push(initial_object()());
3250 }
3251
3252 // object references required
3253 if (is_following_references()) {
3254
3255 // visit each object until all reachable objects have been
3256 // visited or the callback asked to terminate the iteration.
3257 while (!visit_stack()->is_empty()) {
3258 oop o = visit_stack()->pop();
3259 if (!ObjectMarker::visited(o)) {
3260 if (!visit(o)) {
3261 break;
3262 }
3263 }
3264 }
3265 }
3266 }
3267
3268 // iterate over all objects that are reachable from a set of roots
3269 void JvmtiTagMap::iterate_over_reachable_objects(jvmtiHeapRootCallback heap_root_callback,
3270 jvmtiStackReferenceCallback stack_ref_callback,
3271 jvmtiObjectReferenceCallback object_ref_callback,
3272 const void* user_data) {
3273 JavaThread* jt = JavaThread::current();
3274 JVMTIEscapeBarrier eb(jt, true);
3275 eb.deoptimize_objects_all_threads();
3276 MutexLocker ml(Heap_lock);
3277 BasicHeapWalkContext context(heap_root_callback, stack_ref_callback, object_ref_callback);
3278 VM_HeapWalkOperation op(this, Handle(), context, user_data);
3279 VMThread::execute(&op);
3280 }
3281
3282 // iterate over all objects that are reachable from a given object
3283 void JvmtiTagMap::iterate_over_objects_reachable_from_object(jobject object,
3284 jvmtiObjectReferenceCallback object_ref_callback,
3285 const void* user_data) {
3286 oop obj = JNIHandles::resolve(object);
3287 Handle initial_object(Thread::current(), obj);
3288
3289 MutexLocker ml(Heap_lock);
3290 BasicHeapWalkContext context(NULL, NULL, object_ref_callback);
3291 VM_HeapWalkOperation op(this, initial_object, context, user_data);
3292 VMThread::execute(&op);
3293 }
3294
3295 // follow references from an initial object or the GC roots
3296 void JvmtiTagMap::follow_references(jint heap_filter,
3297 Klass* klass,
3298 jobject object,
3299 const jvmtiHeapCallbacks* callbacks,
3300 const void* user_data)
3301 {
3302 oop obj = JNIHandles::resolve(object);
3303 JavaThread* jt = JavaThread::current();
3304 Handle initial_object(jt, obj);
3305 // EA based optimizations that are tagged or reachable from initial_object are already reverted.
3306 JVMTIEscapeBarrier eb(jt,
3307 initial_object.is_null() && !(heap_filter & JVMTI_HEAP_FILTER_UNTAGGED));
3308 eb.deoptimize_objects_all_threads();
3309 MutexLocker ml(Heap_lock);
3310 AdvancedHeapWalkContext context(heap_filter, klass, callbacks);
3311 VM_HeapWalkOperation op(this, initial_object, context, user_data);
3312 VMThread::execute(&op);
3313 }
3314
3315
3316 void JvmtiTagMap::weak_oops_do(BoolObjectClosure* is_alive, OopClosure* f) {
3317 // No locks during VM bring-up (0 threads) and no safepoints after main
3318 // thread creation and before VMThread creation (1 thread); initial GC
3319 // verification can happen in that window which gets to here.
3320 assert(Threads::number_of_threads() <= 1 ||
3321 SafepointSynchronize::is_at_safepoint(),
3322 "must be executed at a safepoint");
3323 if (JvmtiEnv::environments_might_exist()) {
3324 JvmtiEnvIterator it;
3325 for (JvmtiEnvBase* env = it.first(); env != NULL; env = it.next(env)) {
3326 JvmtiTagMap* tag_map = env->tag_map_acquire();
3327 if (tag_map != NULL && !tag_map->is_empty()) {
3328 tag_map->do_weak_oops(is_alive, f);
3329 }
3330 }
3331 }
3332 }
3333
3334 void JvmtiTagMap::do_weak_oops(BoolObjectClosure* is_alive, OopClosure* f) {
3335
3336 // does this environment have the OBJECT_FREE event enabled
3337 bool post_object_free = env()->is_enabled(JVMTI_EVENT_OBJECT_FREE);
3338
3339 // counters used for trace message
3340 int freed = 0;
3341 int moved = 0;
3342
3343 JvmtiTagHashmap* hashmap = this->hashmap();
3344
3345 // reenable sizing (if disabled)
3346 hashmap->set_resizing_enabled(true);
3347
3348 // if the hashmap is empty then we can skip it
3349 if (hashmap->_entry_count == 0) {
3350 return;
3351 }
3352
3353 // now iterate through each entry in the table
3354
3355 JvmtiTagHashmapEntry** table = hashmap->table();
3356 int size = hashmap->size();
3357
3358 JvmtiTagHashmapEntry* delayed_add = NULL;
3359
3360 for (int pos = 0; pos < size; ++pos) {
3361 JvmtiTagHashmapEntry* entry = table[pos];
3362 JvmtiTagHashmapEntry* prev = NULL;
3363
3364 while (entry != NULL) {
3365 JvmtiTagHashmapEntry* next = entry->next();
3366
3367 // has object been GC'ed
3368 if (!is_alive->do_object_b(entry->object_peek())) {
3369 // grab the tag
3370 jlong tag = entry->tag();
3371 guarantee(tag != 0, "checking");
3372
3373 // remove GC'ed entry from hashmap and return the
3374 // entry to the free list
3375 hashmap->remove(prev, pos, entry);
3376 destroy_entry(entry);
3377
3378 // post the event to the profiler
3379 if (post_object_free) {
3380 JvmtiExport::post_object_free(env(), tag);
3381 }
3382
3383 ++freed;
3384 } else {
3385 f->do_oop(entry->object_addr());
3386 oop new_oop = entry->object_peek();
3387
3388 // if the object has moved then re-hash it and move its
3389 // entry to its new location.
3390 unsigned int new_pos = JvmtiTagHashmap::hash(new_oop, size);
3391 if (new_pos != (unsigned int)pos) {
3392 if (prev == NULL) {
3393 table[pos] = next;
3394 } else {
3395 prev->set_next(next);
3396 }
3397 if (new_pos < (unsigned int)pos) {
3398 entry->set_next(table[new_pos]);
3399 table[new_pos] = entry;
3400 } else {
3401 // Delay adding this entry to it's new position as we'd end up
3402 // hitting it again during this iteration.
3403 entry->set_next(delayed_add);
3404 delayed_add = entry;
3405 }
3406 moved++;
3407 } else {
3408 // object didn't move
3409 prev = entry;
3410 }
3411 }
3412
3413 entry = next;
3414 }
3415 }
3416
3417 // Re-add all the entries which were kept aside
3418 while (delayed_add != NULL) {
3419 JvmtiTagHashmapEntry* next = delayed_add->next();
3420 unsigned int pos = JvmtiTagHashmap::hash(delayed_add->object_peek(), size);
3421 delayed_add->set_next(table[pos]);
3422 table[pos] = delayed_add;
3423 delayed_add = next;
3424 }
3425
3426 log_debug(jvmti, objecttagging)("(%d->%d, %d freed, %d total moves)",
3427 hashmap->_entry_count + freed, hashmap->_entry_count, freed, moved);
3428 }