1 /*
2 * Copyright (c) 2003, 2026, 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 "classfile/classLoaderDataGraph.hpp"
26 #include "classfile/javaClasses.inline.hpp"
27 #include "classfile/symbolTable.hpp"
28 #include "classfile/vmClasses.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "gc/shared/collectedHeap.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.hpp"
38 #include "oops/constantPool.inline.hpp"
39 #include "oops/fieldStreams.inline.hpp"
40 #include "oops/flatArrayOop.inline.hpp"
41 #include "oops/inlineKlass.inline.hpp"
42 #include "oops/instanceMirrorKlass.hpp"
43 #include "oops/klass.inline.hpp"
44 #include "oops/objArrayKlass.hpp"
45 #include "oops/objArrayOop.inline.hpp"
46 #include "oops/oop.inline.hpp"
47 #include "oops/oopCast.inline.hpp"
48 #include "oops/typeArrayOop.inline.hpp"
49 #include "oops/valuePayload.inline.hpp"
50 #include "prims/jvmtiEventController.inline.hpp"
51 #include "prims/jvmtiExport.hpp"
52 #include "prims/jvmtiImpl.hpp"
53 #include "prims/jvmtiTagMap.hpp"
54 #include "prims/jvmtiTagMapTable.hpp"
55 #include "prims/jvmtiThreadState.hpp"
56 #include "runtime/continuationWrapper.inline.hpp"
57 #include "runtime/deoptimization.hpp"
58 #include "runtime/frame.inline.hpp"
59 #include "runtime/handles.inline.hpp"
60 #include "runtime/interfaceSupport.inline.hpp"
61 #include "runtime/javaCalls.hpp"
62 #include "runtime/javaThread.inline.hpp"
63 #include "runtime/jniHandles.inline.hpp"
64 #include "runtime/mountUnmountDisabler.hpp"
65 #include "runtime/mutex.hpp"
66 #include "runtime/mutexLocker.hpp"
67 #include "runtime/safepoint.hpp"
68 #include "runtime/threadSMR.hpp"
69 #include "runtime/timerTrace.hpp"
70 #include "runtime/vframe.hpp"
71 #include "runtime/vmOperations.hpp"
72 #include "runtime/vmThread.hpp"
73 #include "utilities/macros.hpp"
74 #include "utilities/objectBitSet.inline.hpp"
75
76 typedef ObjectBitSet<mtServiceability> JVMTIBitSet;
77
78
79 // Helper class to store objects to visit.
80 class JvmtiHeapwalkVisitStack {
81 private:
82 enum {
83 initial_visit_stack_size = 4000
84 };
85
86 GrowableArray<JvmtiHeapwalkObject>* _visit_stack;
87 JVMTIBitSet _bitset;
88
89 static GrowableArray<JvmtiHeapwalkObject>* create_visit_stack() {
90 return new (mtServiceability) GrowableArray<JvmtiHeapwalkObject>(initial_visit_stack_size, mtServiceability);
91 }
92
93 public:
94 JvmtiHeapwalkVisitStack(): _visit_stack(create_visit_stack()) {
95 }
96 ~JvmtiHeapwalkVisitStack() {
97 if (_visit_stack != nullptr) {
98 delete _visit_stack;
99 }
100 }
101
102 bool is_empty() const {
103 return _visit_stack->is_empty();
104 }
105
106 void push(const JvmtiHeapwalkObject& obj) {
107 _visit_stack->push(obj);
108 }
109
110 // If the object hasn't been visited then push it onto the visit stack
111 // so that it will be visited later.
112 void check_for_visit(const JvmtiHeapwalkObject& obj) {
113 if (!is_visited(obj)) {
114 _visit_stack->push(obj);
115 }
116 }
117
118 JvmtiHeapwalkObject pop() {
119 return _visit_stack->pop();
120 }
121
122 bool is_visited(const JvmtiHeapwalkObject& obj) /*const*/ { // TODO: _bitset.is_marked() should be const
123 // The method is called only for objects from visit_stack to ensure an object is not visited twice.
124 // Flat objects can be added to visit_stack only when we visit their holder object, so we cannot get duplicate reference to it.
125 if (obj.is_flat()) {
126 return false;
127 }
128 return _bitset.is_marked(obj.obj());
129 }
130
131 void mark_visited(const JvmtiHeapwalkObject& obj) {
132 if (!obj.is_flat()) {
133 _bitset.mark_obj(obj.obj());
134 }
135 }
136 };
137
138 bool JvmtiTagMap::_has_object_free_events = false;
139
140 // create a JvmtiTagMap
141 JvmtiTagMap::JvmtiTagMap(JvmtiEnv* env) :
142 _env(env),
143 _lock(Mutex::nosafepoint, "JvmtiTagMap_lock"),
144 _needs_cleaning(false),
145 _posting_events(false),
146 _converting_flat_object(false) {
147
148 assert(JvmtiThreadState_lock->is_locked(), "sanity check");
149 assert(((JvmtiEnvBase *)env)->tag_map() == nullptr, "tag map already exists for environment");
150
151 _hashmap = new JvmtiTagMapTable();
152 _flat_hashmap = new JvmtiFlatTagMapTable();
153
154 // finally add us to the environment
155 ((JvmtiEnvBase *)env)->release_set_tag_map(this);
156 }
157
158 // destroy a JvmtiTagMap
159 JvmtiTagMap::~JvmtiTagMap() {
160
161 // no lock acquired as we assume the enclosing environment is
162 // also being destroyed.
163 ((JvmtiEnvBase *)_env)->set_tag_map(nullptr);
164
165 // finally destroy the hashmap
166 delete _hashmap;
167 _hashmap = nullptr;
168 delete _flat_hashmap;
169 }
170
171 // Called by env_dispose() to reclaim memory before deallocation.
172 // Remove all the entries but keep the empty table intact.
173 // This needs the table lock.
174 void JvmtiTagMap::clear() {
175 MutexLocker ml(lock(), Mutex::_no_safepoint_check_flag);
176 _hashmap->clear();
177 _flat_hashmap->clear();
178 }
179
180 // returns the tag map for the given environments. If the tag map
181 // doesn't exist then it is created.
182 JvmtiTagMap* JvmtiTagMap::tag_map_for(JvmtiEnv* env) {
183 JvmtiTagMap* tag_map = ((JvmtiEnvBase*)env)->tag_map_acquire();
184 if (tag_map == nullptr) {
185 MutexLocker mu(JvmtiThreadState_lock);
186 tag_map = ((JvmtiEnvBase*)env)->tag_map();
187 if (tag_map == nullptr) {
188 tag_map = new JvmtiTagMap(env);
189 }
190 } else {
191 DEBUG_ONLY(JavaThread::current()->check_possible_safepoint());
192 }
193 return tag_map;
194 }
195
196 // returns true if the hashmaps are empty
197 bool JvmtiTagMap::is_empty() const {
198 assert(SafepointSynchronize::is_at_safepoint() || is_locked(), "checking");
199 return _hashmap->is_empty() && _flat_hashmap->is_empty();
200 }
201
202 // This checks for posting before operations that use
203 // this tagmap table.
204 void JvmtiTagMap::check_hashmap(GrowableArray<jlong>* objects) {
205 assert(is_locked(), "checking");
206
207 if (is_empty()) { return; }
208
209 if (_needs_cleaning &&
210 objects != nullptr &&
211 env()->is_enabled(JVMTI_EVENT_OBJECT_FREE)) {
212 remove_dead_entries_locked(objects);
213 }
214 }
215
216 // This checks for posting and is called from the heap walks.
217 void JvmtiTagMap::check_hashmaps_for_heapwalk(GrowableArray<jlong>* objects) {
218 assert(SafepointSynchronize::is_at_safepoint(), "called from safepoints");
219
220 // Verify that the tag map tables are valid and unconditionally post events
221 // that are expected to be posted before gc_notification.
222 JvmtiEnvIterator it;
223 for (JvmtiEnv* env = it.first(); env != nullptr; env = it.next(env)) {
224 JvmtiTagMap* tag_map = env->tag_map_acquire();
225 if (tag_map != nullptr) {
226 // The ZDriver may be walking the hashmaps concurrently so this lock is needed.
227 MutexLocker ml(tag_map->lock(), Mutex::_no_safepoint_check_flag);
228 tag_map->check_hashmap(objects);
229 }
230 }
231 }
232
233 // Converts entries from JvmtiFlatTagMapTable to JvmtiTagMapTable in batches.
234 // 1. (JvmtiTagMap is locked)
235 // reads entries from JvmtiFlatTagMapTable (describe flat value objects);
236 // 2. (JvmtiTagMap is unlocked)
237 // creates heap-allocated copies of the flat object;
238 // 3. (JvmtiTagMap is locked)
239 // ensures source entry still exists, removes it from JvmtiFlatTagMapTable, adds new entry to JvmtiTagMapTable.
240 // If some error occurs in step 2 (OOM?), the process stops.
241 class JvmtiTagMapFlatEntryConverter: public StackObj {
242 private:
243 struct Entry {
244 // source flat value object
245 Handle holder;
246 int offset;
247 InlineKlass* inline_klass;
248 LayoutKind layout_kind;
249 // converted heap-allocated object
250 Handle dst;
251
252 Entry(): holder(), offset(0), inline_klass(nullptr), dst() {}
253 Entry(Handle holder, int offset, InlineKlass* inline_klass, LayoutKind lk)
254 : holder(holder), offset(offset), inline_klass(inline_klass), layout_kind(lk), dst() {}
255 };
256
257 int _batch_size;
258 GrowableArray<Entry> _entries;
259 bool _has_error;
260
261 public:
262 JvmtiTagMapFlatEntryConverter(int batch_size): _batch_size(batch_size), _entries(batch_size, mtServiceability), _has_error(false) { }
263 ~JvmtiTagMapFlatEntryConverter() {}
264
265 // returns false if there is nothing to convert
266 bool import_entries(JvmtiFlatTagMapTable* table) {
267 if (_has_error) {
268 // stop the process to avoid infinite loop
269 return false;
270 }
271
272 class Importer: public JvmtiFlatTagMapKeyClosure {
273 private:
274 GrowableArray<Entry>& _entries;
275 int _batch_size;
276 public:
277 Importer(GrowableArray<Entry>& entries, int batch_size): _entries(entries), _batch_size(batch_size) {}
278
279 bool do_entry(JvmtiFlatTagMapKey& key, jlong& tag) {
280 Entry entry(Handle(Thread::current(), key.holder()), key.offset(), key.inline_klass(), key.layout_kind());
281 _entries.append(entry);
282
283 return _entries.length() < _batch_size;
284 }
285 } importer(_entries, _batch_size);
286 table->entry_iterate(&importer);
287
288 return !_entries.is_empty();
289 }
290
291 void convert() {
292 for (int i = 0; i < _entries.length(); i++) {
293 EXCEPTION_MARK;
294 Entry& entry = _entries.at(i);
295 FlatValuePayload payload = FlatValuePayload::construct_from_parts(
296 entry.holder(), entry.offset, entry.inline_klass, entry.layout_kind);
297 oop obj = payload.read(JavaThread::current());
298
299 if (HAS_PENDING_EXCEPTION) {
300 tty->print_cr("Exception in JvmtiTagMapFlatEntryConverter: ");
301 java_lang_Throwable::print(PENDING_EXCEPTION, tty);
302 tty->cr();
303 CLEAR_PENDING_EXCEPTION;
304 // stop the conversion
305 _has_error = true;
306 } else {
307 entry.dst = Handle(Thread::current(), obj);
308 }
309 }
310 }
311
312 // returns number of converted entries
313 int move(JvmtiFlatTagMapTable* src_table, JvmtiTagMapTable* dst_table) {
314 int count = 0;
315 for (int i = 0; i < _entries.length(); i++) {
316 Entry& entry = _entries.at(i);
317 if (entry.dst() == nullptr) {
318 // some error during conversion, skip the entry
319 continue;
320 }
321 JvmtiHeapwalkObject obj(entry.holder(), entry.offset, entry.inline_klass, entry.layout_kind);
322 jlong tag = src_table->remove(obj);
323
324 if (tag != 0) { // ensure the entry is still in the src_table
325 dst_table->add(entry.dst(), tag);
326 count++;
327 } else {
328
329 }
330 }
331 // and clean the array
332 _entries.clear();
333 return count;
334 }
335 };
336
337 void JvmtiTagMap::convert_flat_object_entries() {
338 Thread* current = Thread::current();
339 assert(current->is_Java_thread(), "must be executed on JavaThread");
340
341 log_debug(jvmti, table)("convert_flat_object_entries, main table size = %d, flat table size = %d",
342 _hashmap->number_of_entries(), _flat_hashmap->number_of_entries());
343
344 {
345 MonitorLocker ml(lock(), Mutex::_no_safepoint_check_flag);
346 // If another thread is converting, let it finish.
347 while (_converting_flat_object) {
348 ml.wait();
349 }
350 if (_flat_hashmap->is_empty()) {
351 // nothing to convert
352 return;
353 }
354 _converting_flat_object = true;
355 }
356
357 const int BATCH_SIZE = 1024;
358 JvmtiTagMapFlatEntryConverter converter(BATCH_SIZE);
359
360 int count = 0;
361 while (true) {
362 HandleMark hm(current);
363 {
364 MonitorLocker ml(lock(), Mutex::_no_safepoint_check_flag);
365 if (!converter.import_entries(_flat_hashmap)) {
366 break;
367 }
368 }
369 // Convert flat objects to heap-allocated without table lock (so agent callbacks can get/set tags).
370 converter.convert();
371 {
372 MonitorLocker ml(lock(), Mutex::_no_safepoint_check_flag);
373 count += converter.move(_flat_hashmap, _hashmap);
374 }
375 }
376
377 log_info(jvmti, table)("%d flat value objects are converted, flat table size = %d",
378 count, _flat_hashmap->number_of_entries());
379 {
380 MonitorLocker ml(lock(), Mutex::_no_safepoint_check_flag);
381 _converting_flat_object = false;
382 ml.notify_all();
383 }
384 }
385
386 jlong JvmtiTagMap::find(const JvmtiHeapwalkObject& obj) const {
387 jlong tag = _hashmap->find(obj);
388 if (tag == 0 && obj.is_value()) {
389 tag = _flat_hashmap->find(obj);
390 }
391 return tag;
392 }
393
394 void JvmtiTagMap::add(const JvmtiHeapwalkObject& obj, jlong tag) {
395 if (obj.is_flat()) {
396 // we may have tag for equal (non-flat) object in _hashmap, try to update it 1st
397 if (!_hashmap->update(obj, tag)) {
398 // no entry in _hashmap, add to _flat_hashmap
399 _flat_hashmap->add(obj, tag);
400 }
401 } else {
402 _hashmap->add(obj, tag);
403 }
404 }
405
406 void JvmtiTagMap::remove(const JvmtiHeapwalkObject& obj) {
407 if (!_hashmap->remove(obj)) {
408 if (obj.is_value()) {
409 _flat_hashmap->remove(obj);
410 }
411 }
412 }
413
414 // A CallbackWrapper is a support class for querying and tagging an object
415 // around a callback to a profiler. The constructor does pre-callback
416 // work to get the tag value, klass tag value, ... and the destructor
417 // does the post-callback work of tagging or untagging the object.
418 //
419 // {
420 // CallbackWrapper wrapper(tag_map, o);
421 //
422 // (*callback)(wrapper.klass_tag(), wrapper.obj_size(), wrapper.obj_tag_p(), ...)
423 //
424 // }
425 // wrapper goes out of scope here which results in the destructor
426 // checking to see if the object has been tagged, untagged, or the
427 // tag value has changed.
428 //
429 class CallbackWrapper : public StackObj {
430 private:
431 JvmtiTagMap* _tag_map;
432 const JvmtiHeapwalkObject& _o;
433 jlong _obj_size;
434 jlong _obj_tag;
435 jlong _klass_tag;
436
437 protected:
438 JvmtiTagMap* tag_map() const { return _tag_map; }
439
440 // invoked post-callback to tag, untag, or update the tag of an object
441 void inline post_callback_tag_update(const JvmtiHeapwalkObject& o, JvmtiTagMap* tag_map, jlong obj_tag);
442
443 public:
444 CallbackWrapper(JvmtiTagMap* tag_map, const JvmtiHeapwalkObject& o)
445 : _tag_map(tag_map), _o(o)
446 {
447 assert(Thread::current()->is_VM_thread() || tag_map->is_locked(),
448 "MT unsafe or must be VM thread");
449
450 // object size
451 if (!o.is_flat()) {
452 // common case: we have oop
453 _obj_size = (jlong)o.obj()->size() * wordSize;
454 } else {
455 // flat value object, we know its InstanceKlass
456 assert(_o.inline_klass() != nullptr, "must be");
457 _obj_size = _o.inline_klass()->size() * wordSize;;
458 }
459
460 // get object tag
461 _obj_tag = _tag_map->find(_o);
462
463 // get the class and the class's tag value
464 assert(vmClasses::Class_klass()->is_mirror_instance_klass(), "Is not?");
465
466 _klass_tag = _tag_map->find(_o.klass()->java_mirror());
467 }
468
469 ~CallbackWrapper() {
470 post_callback_tag_update(_o, _tag_map, _obj_tag);
471 }
472
473 inline jlong* obj_tag_p() { return &_obj_tag; }
474 inline jlong obj_size() const { return _obj_size; }
475 inline jlong obj_tag() const { return _obj_tag; }
476 inline jlong klass_tag() const { return _klass_tag; }
477 };
478
479 // callback post-callback to tag, untag, or update the tag of an object
480 void inline CallbackWrapper::post_callback_tag_update(const JvmtiHeapwalkObject& o,
481 JvmtiTagMap* tag_map,
482 jlong obj_tag) {
483 if (obj_tag == 0) {
484 // callback has untagged the object, remove the entry if present
485 tag_map->remove(o);
486 } else {
487 // object was previously tagged or not present - the callback may have
488 // changed the tag value
489 assert(Thread::current()->is_VM_thread(), "must be VMThread");
490 tag_map->add(o, obj_tag);
491 }
492 }
493
494 // An extended CallbackWrapper used when reporting an object reference
495 // to the agent.
496 //
497 // {
498 // TwoOopCallbackWrapper wrapper(tag_map, referrer, o);
499 //
500 // (*callback)(wrapper.klass_tag(),
501 // wrapper.obj_size(),
502 // wrapper.obj_tag_p()
503 // wrapper.referrer_tag_p(), ...)
504 //
505 // }
506 // wrapper goes out of scope here which results in the destructor
507 // checking to see if the referrer object has been tagged, untagged,
508 // or the tag value has changed.
509 //
510 class TwoOopCallbackWrapper : public CallbackWrapper {
511 private:
512 const JvmtiHeapwalkObject& _referrer;
513 bool _is_reference_to_self;
514 jlong _referrer_obj_tag;
515 jlong _referrer_klass_tag;
516 jlong* _referrer_tag_p;
517
518 bool is_reference_to_self() const { return _is_reference_to_self; }
519
520 public:
521 TwoOopCallbackWrapper(JvmtiTagMap* tag_map, const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& o) :
522 CallbackWrapper(tag_map, o), _referrer(referrer)
523 {
524 // self reference needs to be handled in a special way
525 _is_reference_to_self = (referrer == o);
526
527 if (_is_reference_to_self) {
528 _referrer_klass_tag = klass_tag();
529 _referrer_tag_p = obj_tag_p();
530 } else {
531 // get object tag
532 _referrer_obj_tag = tag_map->find(_referrer);
533
534 _referrer_tag_p = &_referrer_obj_tag;
535
536 // get referrer class tag.
537 _referrer_klass_tag = tag_map->find(_referrer.klass()->java_mirror());
538 }
539 }
540
541 ~TwoOopCallbackWrapper() {
542 if (!is_reference_to_self()) {
543 post_callback_tag_update(_referrer,
544 tag_map(),
545 _referrer_obj_tag);
546 }
547 }
548
549 // address of referrer tag
550 // (for a self reference this will return the same thing as obj_tag_p())
551 inline jlong* referrer_tag_p() { return _referrer_tag_p; }
552
553 // referrer's class tag
554 inline jlong referrer_klass_tag() { return _referrer_klass_tag; }
555 };
556
557 // tag an object
558 //
559 // This function is performance critical. If many threads attempt to tag objects
560 // around the same time then it's possible that the Mutex associated with the
561 // tag map will be a hot lock.
562 void JvmtiTagMap::set_tag(jobject object, jlong tag) {
563 MutexLocker ml(lock(), Mutex::_no_safepoint_check_flag);
564
565 // SetTag should not post events because the JavaThread has to
566 // transition to native for the callback and this cannot stop for
567 // safepoints with the hashmap lock held.
568 check_hashmap(nullptr); /* don't collect dead objects */
569
570 // resolve the object
571 oop o = JNIHandles::resolve_non_null(object);
572
573 // see if the object is already tagged
574 JvmtiHeapwalkObject obj(o);
575 if (tag == 0) {
576 // remove the entry if present
577 _hashmap->remove(obj);
578 } else {
579 // if the object is already tagged or not present then we add/update
580 // the tag
581 add(obj, tag);
582 }
583 }
584
585 // get the tag for an object
586 jlong JvmtiTagMap::get_tag(jobject object) {
587 MutexLocker ml(lock(), Mutex::_no_safepoint_check_flag);
588
589 // GetTag should not post events because the JavaThread has to
590 // transition to native for the callback and this cannot stop for
591 // safepoints with the hashmap lock held.
592 check_hashmap(nullptr); /* don't collect dead objects */
593
594 // resolve the object
595 oop o = JNIHandles::resolve_non_null(object);
596
597 return find(o);
598 }
599
600
601 // Helper class used to describe the static or instance fields of a class.
602 // For each field it holds the field index (as defined by the JVMTI specification),
603 // the field type, and the offset.
604
605 class ClassFieldDescriptor: public CHeapObj<mtInternal> {
606 private:
607 int _field_index;
608 int _field_offset;
609 char _field_type;
610 InlineKlass* _inline_klass; // nullptr for heap object
611 LayoutKind _layout_kind;
612 public:
613 ClassFieldDescriptor(int index, const FieldStreamBase& fld) :
614 _field_index(index), _field_offset(fld.offset()), _field_type(fld.signature()->char_at(0)) {
615 if (fld.is_flat()) {
616 const fieldDescriptor& fd = fld.field_descriptor();
617 InstanceKlass* holder_klass = fd.field_holder();
618 InlineLayoutInfo* layout_info = holder_klass->inline_layout_info_adr(fd.index());
619 _inline_klass = layout_info->klass();
620 _layout_kind = layout_info->kind();
621 } else {
622 _inline_klass = nullptr;
623 _layout_kind = LayoutKind::REFERENCE;
624 }
625 }
626 int field_index() const { return _field_index; }
627 char field_type() const { return _field_type; }
628 int field_offset() const { return _field_offset; }
629 bool is_flat() const { return _inline_klass != nullptr; }
630 InlineKlass* inline_klass() const { return _inline_klass; }
631 LayoutKind layout_kind() const { return _layout_kind; }
632 };
633
634 class ClassFieldMap: public CHeapObj<mtInternal> {
635 private:
636 enum {
637 initial_field_count = 5
638 };
639
640 // list of field descriptors
641 GrowableArray<ClassFieldDescriptor*>* _fields;
642
643 // constructor
644 ClassFieldMap();
645
646 // calculates number of fields in all interfaces
647 static int interfaces_field_count(InstanceKlass* ik);
648
649 // add a field
650 void add(int index, const FieldStreamBase& fld);
651
652 public:
653 ~ClassFieldMap();
654
655 // access
656 int field_count() { return _fields->length(); }
657 ClassFieldDescriptor* field_at(int i) { return _fields->at(i); }
658
659 // functions to create maps of static or instance fields
660 static ClassFieldMap* create_map_of_static_fields(Klass* k);
661 static ClassFieldMap* create_map_of_instance_fields(Klass* k);
662 };
663
664 ClassFieldMap::ClassFieldMap() {
665 _fields = new (mtServiceability)
666 GrowableArray<ClassFieldDescriptor*>(initial_field_count, mtServiceability);
667 }
668
669 ClassFieldMap::~ClassFieldMap() {
670 for (int i=0; i<_fields->length(); i++) {
671 delete _fields->at(i);
672 }
673 delete _fields;
674 }
675
676 int ClassFieldMap::interfaces_field_count(InstanceKlass* ik) {
677 const Array<InstanceKlass*>* interfaces = ik->transitive_interfaces();
678 int count = 0;
679 for (int i = 0; i < interfaces->length(); i++) {
680 count += interfaces->at(i)->java_fields_count();
681
682 }
683 return count;
684 }
685
686 void ClassFieldMap::add(int index, const FieldStreamBase& fld) {
687 ClassFieldDescriptor* field = new ClassFieldDescriptor(index, fld);
688 _fields->append(field);
689 }
690
691 // Returns a heap allocated ClassFieldMap to describe the static fields
692 // of the given class.
693 ClassFieldMap* ClassFieldMap::create_map_of_static_fields(Klass* k) {
694 InstanceKlass* ik = InstanceKlass::cast(k);
695
696 // create the field map
697 ClassFieldMap* field_map = new ClassFieldMap();
698
699 // Static fields of interfaces and superclasses are reported as references from the interfaces/superclasses.
700 // Need to calculate start index of this class fields: number of fields in all interfaces and superclasses.
701 int index = interfaces_field_count(ik);
702 for (InstanceKlass* super_klass = ik->super(); super_klass != nullptr; super_klass = super_klass->super()) {
703 index += super_klass->java_fields_count();
704 }
705
706 for (JavaFieldStream fld(ik); !fld.done(); fld.next(), index++) {
707 // ignore instance fields
708 if (!fld.access_flags().is_static()) {
709 continue;
710 }
711 field_map->add(index, fld);
712 }
713
714 return field_map;
715 }
716
717 // Returns a heap allocated ClassFieldMap to describe the instance fields
718 // of the given class. All instance fields are included (this means public
719 // and private fields declared in superclasses too).
720 ClassFieldMap* ClassFieldMap::create_map_of_instance_fields(Klass* k) {
721 InstanceKlass* ik = InstanceKlass::cast(k);
722
723 // create the field map
724 ClassFieldMap* field_map = new ClassFieldMap();
725
726 // fields of the superclasses are reported first, so need to know total field number to calculate field indices
727 int total_field_number = interfaces_field_count(ik);
728 for (InstanceKlass* klass = ik; klass != nullptr; klass = klass->super()) {
729 total_field_number += klass->java_fields_count();
730 }
731
732 for (InstanceKlass* klass = ik; klass != nullptr; klass = klass->super()) {
733 JavaFieldStream fld(klass);
734 int start_index = total_field_number - klass->java_fields_count();
735 for (int index = 0; !fld.done(); fld.next(), index++) {
736 // ignore static fields
737 if (fld.access_flags().is_static()) {
738 continue;
739 }
740 field_map->add(start_index + index, fld);
741 }
742 // update total_field_number for superclass (decrease by the field count in the current class)
743 total_field_number = start_index;
744 }
745
746 return field_map;
747 }
748
749 // Helper class used to cache a ClassFileMap for the instance fields of
750 // a cache. A JvmtiCachedClassFieldMap can be cached by an InstanceKlass during
751 // heap iteration and avoid creating a field map for each object in the heap
752 // (only need to create the map when the first instance of a class is encountered).
753 //
754 class JvmtiCachedClassFieldMap : public CHeapObj<mtInternal> {
755 private:
756 enum {
757 initial_class_count = 200
758 };
759 ClassFieldMap* _field_map;
760
761 ClassFieldMap* field_map() const { return _field_map; }
762
763 JvmtiCachedClassFieldMap(ClassFieldMap* field_map);
764 ~JvmtiCachedClassFieldMap();
765
766 static GrowableArray<InstanceKlass*>* _class_list;
767 static void add_to_class_list(InstanceKlass* ik);
768
769 public:
770 // returns the field map for a given klass (returning map cached
771 // by InstanceKlass if possible
772 static ClassFieldMap* get_map_of_instance_fields(Klass* k);
773
774 // removes the field map from all instanceKlasses - should be
775 // called before VM operation completes
776 static void clear_cache();
777
778 // returns the number of ClassFieldMap cached by instanceKlasses
779 static int cached_field_map_count();
780 };
781
782 GrowableArray<InstanceKlass*>* JvmtiCachedClassFieldMap::_class_list;
783
784 JvmtiCachedClassFieldMap::JvmtiCachedClassFieldMap(ClassFieldMap* field_map) {
785 _field_map = field_map;
786 }
787
788 JvmtiCachedClassFieldMap::~JvmtiCachedClassFieldMap() {
789 if (_field_map != nullptr) {
790 delete _field_map;
791 }
792 }
793
794 // Marker class to ensure that the class file map cache is only used in a defined
795 // scope.
796 class ClassFieldMapCacheMark : public StackObj {
797 private:
798 static bool _is_active;
799 public:
800 ClassFieldMapCacheMark() {
801 assert(Thread::current()->is_VM_thread(), "must be VMThread");
802 assert(JvmtiCachedClassFieldMap::cached_field_map_count() == 0, "cache not empty");
803 assert(!_is_active, "ClassFieldMapCacheMark cannot be nested");
804 _is_active = true;
805 }
806 ~ClassFieldMapCacheMark() {
807 JvmtiCachedClassFieldMap::clear_cache();
808 _is_active = false;
809 }
810 static bool is_active() { return _is_active; }
811 };
812
813 bool ClassFieldMapCacheMark::_is_active;
814
815 // record that the given InstanceKlass is caching a field map
816 void JvmtiCachedClassFieldMap::add_to_class_list(InstanceKlass* ik) {
817 if (_class_list == nullptr) {
818 _class_list = new (mtServiceability)
819 GrowableArray<InstanceKlass*>(initial_class_count, mtServiceability);
820 }
821 _class_list->push(ik);
822 }
823
824 // returns the instance field map for the given klass
825 // (returns field map cached by the InstanceKlass if possible)
826 ClassFieldMap* JvmtiCachedClassFieldMap::get_map_of_instance_fields(Klass *k) {
827 assert(Thread::current()->is_VM_thread(), "must be VMThread");
828 assert(ClassFieldMapCacheMark::is_active(), "ClassFieldMapCacheMark not active");
829
830 InstanceKlass* ik = InstanceKlass::cast(k);
831
832 // return cached map if possible
833 JvmtiCachedClassFieldMap* cached_map = ik->jvmti_cached_class_field_map();
834 if (cached_map != nullptr) {
835 assert(cached_map->field_map() != nullptr, "missing field list");
836 return cached_map->field_map();
837 } else {
838 ClassFieldMap* field_map = ClassFieldMap::create_map_of_instance_fields(k);
839 cached_map = new JvmtiCachedClassFieldMap(field_map);
840 ik->set_jvmti_cached_class_field_map(cached_map);
841 add_to_class_list(ik);
842 return field_map;
843 }
844 }
845
846 // remove the fields maps cached from all instanceKlasses
847 void JvmtiCachedClassFieldMap::clear_cache() {
848 assert(Thread::current()->is_VM_thread(), "must be VMThread");
849 if (_class_list != nullptr) {
850 for (int i = 0; i < _class_list->length(); i++) {
851 InstanceKlass* ik = _class_list->at(i);
852 JvmtiCachedClassFieldMap* cached_map = ik->jvmti_cached_class_field_map();
853 assert(cached_map != nullptr, "should not be null");
854 ik->set_jvmti_cached_class_field_map(nullptr);
855 delete cached_map; // deletes the encapsulated field map
856 }
857 delete _class_list;
858 _class_list = nullptr;
859 }
860 }
861
862 // returns the number of ClassFieldMap cached by instanceKlasses
863 int JvmtiCachedClassFieldMap::cached_field_map_count() {
864 return (_class_list == nullptr) ? 0 : _class_list->length();
865 }
866
867 // helper function to indicate if an object is filtered by its tag or class tag
868 static inline bool is_filtered_by_heap_filter(jlong obj_tag,
869 jlong klass_tag,
870 int heap_filter) {
871 // apply the heap filter
872 if (obj_tag != 0) {
873 // filter out tagged objects
874 if (heap_filter & JVMTI_HEAP_FILTER_TAGGED) return true;
875 } else {
876 // filter out untagged objects
877 if (heap_filter & JVMTI_HEAP_FILTER_UNTAGGED) return true;
878 }
879 if (klass_tag != 0) {
880 // filter out objects with tagged classes
881 if (heap_filter & JVMTI_HEAP_FILTER_CLASS_TAGGED) return true;
882 } else {
883 // filter out objects with untagged classes.
884 if (heap_filter & JVMTI_HEAP_FILTER_CLASS_UNTAGGED) return true;
885 }
886 return false;
887 }
888
889 // helper function to indicate if an object is filtered by a klass filter
890 static inline bool is_filtered_by_klass_filter(const JvmtiHeapwalkObject& obj, Klass* klass_filter) {
891 if (klass_filter != nullptr) {
892 if (obj.klass() != klass_filter) {
893 return true;
894 }
895 }
896 return false;
897 }
898
899 // helper function to tell if a field is a primitive field or not
900 static inline bool is_primitive_field_type(char type) {
901 return (type != JVM_SIGNATURE_CLASS && type != JVM_SIGNATURE_ARRAY);
902 }
903
904 // helper function to copy the value from location addr to jvalue.
905 static inline void copy_to_jvalue(jvalue *v, address addr, jvmtiPrimitiveType value_type) {
906 switch (value_type) {
907 case JVMTI_PRIMITIVE_TYPE_BOOLEAN : { v->z = *(jboolean*)addr; break; }
908 case JVMTI_PRIMITIVE_TYPE_BYTE : { v->b = *(jbyte*)addr; break; }
909 case JVMTI_PRIMITIVE_TYPE_CHAR : { v->c = *(jchar*)addr; break; }
910 case JVMTI_PRIMITIVE_TYPE_SHORT : { v->s = *(jshort*)addr; break; }
911 case JVMTI_PRIMITIVE_TYPE_INT : { v->i = *(jint*)addr; break; }
912 case JVMTI_PRIMITIVE_TYPE_LONG : { v->j = *(jlong*)addr; break; }
913 case JVMTI_PRIMITIVE_TYPE_FLOAT : { v->f = *(jfloat*)addr; break; }
914 case JVMTI_PRIMITIVE_TYPE_DOUBLE : { v->d = *(jdouble*)addr; break; }
915 default: ShouldNotReachHere();
916 }
917 }
918
919 // helper function to invoke string primitive value callback
920 // returns visit control flags
921 static jint invoke_string_value_callback(jvmtiStringPrimitiveValueCallback cb,
922 CallbackWrapper* wrapper,
923 const JvmtiHeapwalkObject& obj,
924 void* user_data)
925 {
926 assert(!obj.is_flat(), "cannot be flat");
927 oop str = obj.obj();
928 assert(str->klass() == vmClasses::String_klass(), "not a string");
929
930 typeArrayOop s_value = java_lang_String::value(str);
931
932 // JDK-6584008: the value field may be null if a String instance is
933 // partially constructed.
934 if (s_value == nullptr) {
935 return 0;
936 }
937 // get the string value and length
938 // (string value may be offset from the base)
939 int s_len = java_lang_String::length(str);
940 bool is_latin1 = java_lang_String::is_latin1(str);
941 jchar* value;
942 if (s_len > 0) {
943 if (!is_latin1) {
944 value = s_value->char_at_addr(0);
945 } else {
946 // Inflate latin1 encoded string to UTF16
947 jchar* buf = NEW_C_HEAP_ARRAY(jchar, s_len, mtInternal);
948 for (int i = 0; i < s_len; i++) {
949 buf[i] = ((jchar) s_value->byte_at(i)) & 0xff;
950 }
951 value = &buf[0];
952 }
953 } else {
954 // Don't use char_at_addr(0) if length is 0
955 value = (jchar*) s_value->base(T_CHAR);
956 }
957
958 // invoke the callback
959 jint res = (*cb)(wrapper->klass_tag(),
960 wrapper->obj_size(),
961 wrapper->obj_tag_p(),
962 value,
963 (jint)s_len,
964 user_data);
965
966 if (is_latin1 && s_len > 0) {
967 FREE_C_HEAP_ARRAY(jchar, value);
968 }
969 return res;
970 }
971
972 // helper function to invoke string primitive value callback
973 // returns visit control flags
974 static jint invoke_array_primitive_value_callback(jvmtiArrayPrimitiveValueCallback cb,
975 CallbackWrapper* wrapper,
976 const JvmtiHeapwalkObject& obj,
977 void* user_data)
978 {
979 assert(!obj.is_flat(), "cannot be flat");
980 assert(obj.obj()->is_typeArray(), "not a primitive array");
981
982 // get base address of first element
983 typeArrayOop array = typeArrayOop(obj.obj());
984 BasicType type = TypeArrayKlass::cast(array->klass())->element_type();
985 void* elements = array->base(type);
986
987 // jvmtiPrimitiveType is defined so this mapping is always correct
988 jvmtiPrimitiveType elem_type = (jvmtiPrimitiveType)type2char(type);
989
990 return (*cb)(wrapper->klass_tag(),
991 wrapper->obj_size(),
992 wrapper->obj_tag_p(),
993 (jint)array->length(),
994 elem_type,
995 elements,
996 user_data);
997 }
998
999 // helper function to invoke the primitive field callback for all static fields
1000 // of a given class
1001 static jint invoke_primitive_field_callback_for_static_fields
1002 (CallbackWrapper* wrapper,
1003 oop obj,
1004 jvmtiPrimitiveFieldCallback cb,
1005 void* user_data)
1006 {
1007 // for static fields only the index will be set
1008 static jvmtiHeapReferenceInfo reference_info = { 0 };
1009
1010 assert(obj->klass() == vmClasses::Class_klass(), "not a class");
1011 if (java_lang_Class::is_primitive(obj)) {
1012 return 0;
1013 }
1014 Klass* klass = java_lang_Class::as_Klass(obj);
1015
1016 // ignore classes for object and type arrays
1017 if (!klass->is_instance_klass()) {
1018 return 0;
1019 }
1020
1021 // ignore classes which aren't linked yet
1022 InstanceKlass* ik = InstanceKlass::cast(klass);
1023 if (!ik->is_linked()) {
1024 return 0;
1025 }
1026
1027 // get the field map
1028 ClassFieldMap* field_map = ClassFieldMap::create_map_of_static_fields(klass);
1029
1030 // invoke the callback for each static primitive field
1031 for (int i=0; i<field_map->field_count(); i++) {
1032 ClassFieldDescriptor* field = field_map->field_at(i);
1033
1034 // ignore non-primitive fields
1035 char type = field->field_type();
1036 if (!is_primitive_field_type(type)) {
1037 continue;
1038 }
1039 // one-to-one mapping
1040 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
1041
1042 // get offset and field value
1043 int offset = field->field_offset();
1044 address addr = cast_from_oop<address>(klass->java_mirror()) + offset;
1045 jvalue value;
1046 copy_to_jvalue(&value, addr, value_type);
1047
1048 // field index
1049 reference_info.field.index = field->field_index();
1050
1051 // invoke the callback
1052 jint res = (*cb)(JVMTI_HEAP_REFERENCE_STATIC_FIELD,
1053 &reference_info,
1054 wrapper->klass_tag(),
1055 wrapper->obj_tag_p(),
1056 value,
1057 value_type,
1058 user_data);
1059 if (res & JVMTI_VISIT_ABORT) {
1060 delete field_map;
1061 return res;
1062 }
1063 }
1064
1065 delete field_map;
1066 return 0;
1067 }
1068
1069 // helper function to invoke the primitive field callback for all instance fields
1070 // of a given object
1071 static jint invoke_primitive_field_callback_for_instance_fields(
1072 CallbackWrapper* wrapper,
1073 const JvmtiHeapwalkObject& obj,
1074 jvmtiPrimitiveFieldCallback cb,
1075 void* user_data)
1076 {
1077 // for instance fields only the index will be set
1078 static jvmtiHeapReferenceInfo reference_info = { 0 };
1079
1080 // get the map of the instance fields
1081 ClassFieldMap* fields = JvmtiCachedClassFieldMap::get_map_of_instance_fields(obj.klass());
1082
1083 // invoke the callback for each instance primitive field
1084 for (int i=0; i<fields->field_count(); i++) {
1085 ClassFieldDescriptor* field = fields->field_at(i);
1086
1087 // ignore non-primitive fields
1088 char type = field->field_type();
1089 if (!is_primitive_field_type(type)) {
1090 continue;
1091 }
1092 // one-to-one mapping
1093 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
1094
1095 // get field value
1096 address addr = cast_from_oop<address>(obj.obj()) + obj.offset() + field->field_offset();
1097 jvalue value;
1098 copy_to_jvalue(&value, addr, value_type);
1099
1100 // field index
1101 reference_info.field.index = field->field_index();
1102
1103 // invoke the callback
1104 jint res = (*cb)(JVMTI_HEAP_REFERENCE_FIELD,
1105 &reference_info,
1106 wrapper->klass_tag(),
1107 wrapper->obj_tag_p(),
1108 value,
1109 value_type,
1110 user_data);
1111 if (res & JVMTI_VISIT_ABORT) {
1112 return res;
1113 }
1114 }
1115 return 0;
1116 }
1117
1118
1119 // VM operation to iterate over all objects in the heap (both reachable
1120 // and unreachable)
1121 class VM_HeapIterateOperation: public VM_Operation {
1122 private:
1123 ObjectClosure* _blk;
1124 GrowableArray<jlong>* const _dead_objects;
1125 public:
1126 VM_HeapIterateOperation(ObjectClosure* blk, GrowableArray<jlong>* objects) :
1127 _blk(blk), _dead_objects(objects) { }
1128
1129 VMOp_Type type() const { return VMOp_HeapIterateOperation; }
1130 void doit() {
1131 // allows class files maps to be cached during iteration
1132 ClassFieldMapCacheMark cm;
1133
1134 JvmtiTagMap::check_hashmaps_for_heapwalk(_dead_objects);
1135
1136 // make sure that heap is parsable (fills TLABs with filler objects)
1137 Universe::heap()->ensure_parsability(false); // no need to retire TLABs
1138
1139 // Verify heap before iteration - if the heap gets corrupted then
1140 // JVMTI's IterateOverHeap will crash.
1141 if (VerifyBeforeIteration) {
1142 Universe::verify();
1143 }
1144
1145 // do the iteration
1146 Universe::heap()->object_iterate(_blk);
1147 }
1148 };
1149
1150
1151 // An ObjectClosure used to support the deprecated IterateOverHeap and
1152 // IterateOverInstancesOfClass functions
1153 class IterateOverHeapObjectClosure: public ObjectClosure {
1154 private:
1155 JvmtiTagMap* _tag_map;
1156 Klass* _klass;
1157 jvmtiHeapObjectFilter _object_filter;
1158 jvmtiHeapObjectCallback _heap_object_callback;
1159 const void* _user_data;
1160
1161 // accessors
1162 JvmtiTagMap* tag_map() const { return _tag_map; }
1163 jvmtiHeapObjectFilter object_filter() const { return _object_filter; }
1164 jvmtiHeapObjectCallback object_callback() const { return _heap_object_callback; }
1165 Klass* klass() const { return _klass; }
1166 const void* user_data() const { return _user_data; }
1167
1168 // indicates if iteration has been aborted
1169 bool _iteration_aborted;
1170 bool is_iteration_aborted() const { return _iteration_aborted; }
1171 void set_iteration_aborted(bool aborted) { _iteration_aborted = aborted; }
1172
1173 public:
1174 IterateOverHeapObjectClosure(JvmtiTagMap* tag_map,
1175 Klass* klass,
1176 jvmtiHeapObjectFilter object_filter,
1177 jvmtiHeapObjectCallback heap_object_callback,
1178 const void* user_data) :
1179 _tag_map(tag_map),
1180 _klass(klass),
1181 _object_filter(object_filter),
1182 _heap_object_callback(heap_object_callback),
1183 _user_data(user_data),
1184 _iteration_aborted(false)
1185 {
1186 }
1187
1188 void do_object(oop o);
1189 };
1190
1191 // invoked for each object in the heap
1192 void IterateOverHeapObjectClosure::do_object(oop o) {
1193 assert(o != nullptr, "Heap iteration should never produce null!");
1194 // check if iteration has been halted
1195 if (is_iteration_aborted()) return;
1196
1197 // instanceof check when filtering by klass
1198 if (klass() != nullptr && !o->is_a(klass())) {
1199 return;
1200 }
1201
1202 // skip if object is a dormant shared object whose mirror hasn't been loaded
1203 if (o->klass()->java_mirror() == nullptr) {
1204 log_debug(aot, heap)("skipped dormant archived object " INTPTR_FORMAT " (%s)", p2i(o),
1205 o->klass()->external_name());
1206 return;
1207 }
1208
1209 // prepare for the calllback
1210 JvmtiHeapwalkObject wrapper_obj(o);
1211 CallbackWrapper wrapper(tag_map(), wrapper_obj);
1212
1213 // if the object is tagged and we're only interested in untagged objects
1214 // then don't invoke the callback. Similarly, if the object is untagged
1215 // and we're only interested in tagged objects we skip the callback.
1216 if (wrapper.obj_tag() != 0) {
1217 if (object_filter() == JVMTI_HEAP_OBJECT_UNTAGGED) return;
1218 } else {
1219 if (object_filter() == JVMTI_HEAP_OBJECT_TAGGED) return;
1220 }
1221
1222 // invoke the agent's callback
1223 jvmtiIterationControl control = (*object_callback())(wrapper.klass_tag(),
1224 wrapper.obj_size(),
1225 wrapper.obj_tag_p(),
1226 (void*)user_data());
1227 if (control == JVMTI_ITERATION_ABORT) {
1228 set_iteration_aborted(true);
1229 }
1230 }
1231
1232 // An ObjectClosure used to support the IterateThroughHeap function
1233 class IterateThroughHeapObjectClosure: public ObjectClosure {
1234 private:
1235 JvmtiTagMap* _tag_map;
1236 Klass* _klass;
1237 int _heap_filter;
1238 const jvmtiHeapCallbacks* _callbacks;
1239 const void* _user_data;
1240
1241 // accessor functions
1242 JvmtiTagMap* tag_map() const { return _tag_map; }
1243 int heap_filter() const { return _heap_filter; }
1244 const jvmtiHeapCallbacks* callbacks() const { return _callbacks; }
1245 Klass* klass() const { return _klass; }
1246 const void* user_data() const { return _user_data; }
1247
1248 // indicates if the iteration has been aborted
1249 bool _iteration_aborted;
1250 bool is_iteration_aborted() const { return _iteration_aborted; }
1251
1252 // used to check the visit control flags. If the abort flag is set
1253 // then we set the iteration aborted flag so that the iteration completes
1254 // without processing any further objects
1255 bool check_flags_for_abort(jint flags) {
1256 bool is_abort = (flags & JVMTI_VISIT_ABORT) != 0;
1257 if (is_abort) {
1258 _iteration_aborted = true;
1259 }
1260 return is_abort;
1261 }
1262
1263 void visit_object(const JvmtiHeapwalkObject& obj);
1264 void visit_flat_fields(const JvmtiHeapwalkObject& obj);
1265 void visit_flat_array_elements(const JvmtiHeapwalkObject& obj);
1266
1267 public:
1268 IterateThroughHeapObjectClosure(JvmtiTagMap* tag_map,
1269 Klass* klass,
1270 int heap_filter,
1271 const jvmtiHeapCallbacks* heap_callbacks,
1272 const void* user_data) :
1273 _tag_map(tag_map),
1274 _klass(klass),
1275 _heap_filter(heap_filter),
1276 _callbacks(heap_callbacks),
1277 _user_data(user_data),
1278 _iteration_aborted(false)
1279 {
1280 }
1281
1282 void do_object(oop obj);
1283 };
1284
1285 // invoked for each object in the heap
1286 void IterateThroughHeapObjectClosure::do_object(oop obj) {
1287 assert(obj != nullptr, "Heap iteration should never produce null!");
1288 // check if iteration has been halted
1289 if (is_iteration_aborted()) return;
1290
1291 // skip if object is a dormant shared object whose mirror hasn't been loaded
1292 if (obj != nullptr && obj->klass()->java_mirror() == nullptr) {
1293 log_debug(aot, heap)("skipped dormant archived object " INTPTR_FORMAT " (%s)", p2i(obj),
1294 obj->klass()->external_name());
1295 return;
1296 }
1297
1298 visit_object(obj);
1299 }
1300
1301 void IterateThroughHeapObjectClosure::visit_object(const JvmtiHeapwalkObject& obj) {
1302 // apply class filter
1303 if (is_filtered_by_klass_filter(obj, klass())) return;
1304
1305 // prepare for callback
1306 CallbackWrapper wrapper(tag_map(), obj);
1307
1308 // check if filtered by the heap filter
1309 if (is_filtered_by_heap_filter(wrapper.obj_tag(), wrapper.klass_tag(), heap_filter())) {
1310 return;
1311 }
1312
1313 // for arrays we need the length, otherwise -1
1314 bool is_array = obj.klass()->is_array_klass();
1315 int len = is_array ? arrayOop(obj.obj())->length() : -1;
1316
1317 // invoke the object callback (if callback is provided)
1318 if (callbacks()->heap_iteration_callback != nullptr) {
1319 jvmtiHeapIterationCallback cb = callbacks()->heap_iteration_callback;
1320 jint res = (*cb)(wrapper.klass_tag(),
1321 wrapper.obj_size(),
1322 wrapper.obj_tag_p(),
1323 (jint)len,
1324 (void*)user_data());
1325 if (check_flags_for_abort(res)) return;
1326 }
1327
1328 // for objects and classes we report primitive fields if callback provided
1329 if (callbacks()->primitive_field_callback != nullptr && obj.klass()->is_instance_klass()) {
1330 jint res;
1331 jvmtiPrimitiveFieldCallback cb = callbacks()->primitive_field_callback;
1332 if (obj.klass() == vmClasses::Class_klass()) {
1333 assert(!obj.is_flat(), "Class object cannot be flattened");
1334 res = invoke_primitive_field_callback_for_static_fields(&wrapper,
1335 obj.obj(),
1336 cb,
1337 (void*)user_data());
1338 } else {
1339 res = invoke_primitive_field_callback_for_instance_fields(&wrapper,
1340 obj,
1341 cb,
1342 (void*)user_data());
1343 }
1344 if (check_flags_for_abort(res)) return;
1345 }
1346
1347 // string callback
1348 if (!is_array &&
1349 callbacks()->string_primitive_value_callback != nullptr &&
1350 obj.klass() == vmClasses::String_klass()) {
1351 jint res = invoke_string_value_callback(
1352 callbacks()->string_primitive_value_callback,
1353 &wrapper,
1354 obj,
1355 (void*)user_data());
1356 if (check_flags_for_abort(res)) return;
1357 }
1358
1359 // array callback
1360 if (is_array &&
1361 callbacks()->array_primitive_value_callback != nullptr &&
1362 obj.klass()->is_typeArray_klass()) {
1363 jint res = invoke_array_primitive_value_callback(
1364 callbacks()->array_primitive_value_callback,
1365 &wrapper,
1366 obj,
1367 (void*)user_data());
1368 if (check_flags_for_abort(res)) return;
1369 }
1370
1371 // All info for the object is reported.
1372
1373 // If the object has flat fields, report them as heap objects.
1374 if (obj.klass()->is_instance_klass()) {
1375 if (InstanceKlass::cast(obj.klass())->has_inlined_fields()) {
1376 visit_flat_fields(obj);
1377 // check if iteration has been halted
1378 if (is_iteration_aborted()) {
1379 return;
1380 }
1381 }
1382 }
1383 // If the object is flat array, report all elements as heap objects.
1384 if (is_array && obj.obj()->is_flatArray()) {
1385 assert(!obj.is_flat(), "Array object cannot be flattened");
1386 visit_flat_array_elements(obj);
1387 }
1388 }
1389
1390 void IterateThroughHeapObjectClosure::visit_flat_fields(const JvmtiHeapwalkObject& obj) {
1391 // iterate over instance fields
1392 ClassFieldMap* fields = JvmtiCachedClassFieldMap::get_map_of_instance_fields(obj.klass());
1393 for (int i = 0; i < fields->field_count(); i++) {
1394 ClassFieldDescriptor* field = fields->field_at(i);
1395 // skip non-flat and (for safety) primitive fields
1396 if (!field->is_flat() || is_primitive_field_type(field->field_type())) {
1397 continue;
1398 }
1399
1400 int field_offset = field->field_offset();
1401 if (obj.is_flat()) {
1402 // the object is inlined, its fields are stored without the header
1403 field_offset += obj.offset() - obj.inline_klass()->payload_offset();
1404 }
1405 // check for possible nulls
1406 if (LayoutKindHelper::is_nullable_flat(field->layout_kind())) {
1407 address payload = cast_from_oop<address>(obj.obj()) + field_offset;
1408 if (field->inline_klass()->is_payload_marked_as_null(payload)) {
1409 continue;
1410 }
1411 }
1412 JvmtiHeapwalkObject field_obj(obj.obj(), field_offset, field->inline_klass(), field->layout_kind());
1413
1414 visit_object(field_obj);
1415
1416 // check if iteration has been halted
1417 if (is_iteration_aborted()) {
1418 return;
1419 }
1420 }
1421 }
1422
1423 void IterateThroughHeapObjectClosure::visit_flat_array_elements(const JvmtiHeapwalkObject& obj) {
1424 assert(!obj.is_flat() && obj.obj()->is_flatArray() , "sanity check");
1425 flatArrayOop array = flatArrayOop(obj.obj());
1426 FlatArrayKlass* fak = array->klass();
1427 InlineKlass* vk = fak->element_klass();
1428 bool need_null_check = LayoutKindHelper::is_nullable_flat(fak->layout_kind());
1429
1430 for (int index = 0; index < array->length(); index++) {
1431 address addr = (address)array->value_at_addr(index, fak->layout_helper());
1432 // check for null
1433 if (need_null_check) {
1434 if (vk->is_payload_marked_as_null(addr)) {
1435 continue;
1436 }
1437 }
1438
1439 // offset in the array oop
1440 int offset = (int)(addr - cast_from_oop<address>(array));
1441 JvmtiHeapwalkObject elem(obj.obj(), offset, vk, fak->layout_kind());
1442
1443 visit_object(elem);
1444
1445 // check if iteration has been halted
1446 if (is_iteration_aborted()) {
1447 return;
1448 }
1449 }
1450 }
1451
1452 // Deprecated function to iterate over all objects in the heap
1453 void JvmtiTagMap::iterate_over_heap(jvmtiHeapObjectFilter object_filter,
1454 Klass* klass,
1455 jvmtiHeapObjectCallback heap_object_callback,
1456 const void* user_data)
1457 {
1458 // EA based optimizations on tagged objects are already reverted.
1459 EscapeBarrier eb(object_filter == JVMTI_HEAP_OBJECT_UNTAGGED ||
1460 object_filter == JVMTI_HEAP_OBJECT_EITHER,
1461 JavaThread::current());
1462 eb.deoptimize_objects_all_threads();
1463 Arena dead_object_arena(mtServiceability);
1464 GrowableArray <jlong> dead_objects(&dead_object_arena, 10, 0, 0);
1465 {
1466 MutexLocker ml(Heap_lock);
1467 IterateOverHeapObjectClosure blk(this,
1468 klass,
1469 object_filter,
1470 heap_object_callback,
1471 user_data);
1472 VM_HeapIterateOperation op(&blk, &dead_objects);
1473 VMThread::execute(&op);
1474 }
1475 convert_flat_object_entries();
1476
1477 // Post events outside of Heap_lock
1478 post_dead_objects(&dead_objects);
1479 }
1480
1481
1482 // Iterates over all objects in the heap
1483 void JvmtiTagMap::iterate_through_heap(jint heap_filter,
1484 Klass* klass,
1485 const jvmtiHeapCallbacks* callbacks,
1486 const void* user_data)
1487 {
1488 // EA based optimizations on tagged objects are already reverted.
1489 EscapeBarrier eb(!(heap_filter & JVMTI_HEAP_FILTER_UNTAGGED), JavaThread::current());
1490 eb.deoptimize_objects_all_threads();
1491
1492 Arena dead_object_arena(mtServiceability);
1493 GrowableArray<jlong> dead_objects(&dead_object_arena, 10, 0, 0);
1494 {
1495 MutexLocker ml(Heap_lock);
1496 IterateThroughHeapObjectClosure blk(this,
1497 klass,
1498 heap_filter,
1499 callbacks,
1500 user_data);
1501 VM_HeapIterateOperation op(&blk, &dead_objects);
1502 VMThread::execute(&op);
1503 }
1504 convert_flat_object_entries();
1505
1506 // Post events outside of Heap_lock
1507 post_dead_objects(&dead_objects);
1508 }
1509
1510 void JvmtiTagMap::remove_dead_entries_locked(GrowableArray<jlong>* objects) {
1511 assert(is_locked(), "precondition");
1512 if (_needs_cleaning) {
1513 // Recheck whether to post object free events under the lock.
1514 if (!env()->is_enabled(JVMTI_EVENT_OBJECT_FREE)) {
1515 objects = nullptr;
1516 }
1517 log_info(jvmti, table)("TagMap table needs cleaning%s",
1518 ((objects != nullptr) ? " and posting" : ""));
1519 _hashmap->remove_dead_entries(objects);
1520 _needs_cleaning = false;
1521 }
1522 }
1523
1524 void JvmtiTagMap::remove_dead_entries(GrowableArray<jlong>* objects) {
1525 MutexLocker ml(lock(), Mutex::_no_safepoint_check_flag);
1526 remove_dead_entries_locked(objects);
1527 }
1528
1529 void JvmtiTagMap::post_dead_objects(GrowableArray<jlong>* const objects) {
1530 assert(Thread::current()->is_Java_thread(), "Must post from JavaThread");
1531 if (objects != nullptr && objects->length() > 0) {
1532 JvmtiExport::post_object_free(env(), objects);
1533 log_info(jvmti, table)("%d free object posted", objects->length());
1534 }
1535 }
1536
1537 void JvmtiTagMap::remove_and_post_dead_objects() {
1538 ResourceMark rm;
1539 GrowableArray<jlong> objects;
1540 remove_dead_entries(&objects);
1541 post_dead_objects(&objects);
1542 }
1543
1544 void JvmtiTagMap::flush_object_free_events() {
1545 assert_not_at_safepoint();
1546 if (env()->is_enabled(JVMTI_EVENT_OBJECT_FREE)) {
1547 {
1548 // The other thread can block for safepoints during event callbacks, so ensure we
1549 // are safepoint-safe while waiting.
1550 ThreadBlockInVM tbivm(JavaThread::current());
1551 MonitorLocker ml(lock(), Mutex::_no_safepoint_check_flag);
1552 while (_posting_events) {
1553 ml.wait();
1554 }
1555
1556 if (!_needs_cleaning || is_empty()) {
1557 _needs_cleaning = false;
1558 return;
1559 }
1560 _posting_events = true;
1561 } // Drop the lock so we can do the cleaning on the VM thread.
1562 // Needs both cleaning and event posting (up to some other thread
1563 // getting there first after we dropped the lock).
1564 remove_and_post_dead_objects();
1565 {
1566 MonitorLocker ml(lock(), Mutex::_no_safepoint_check_flag);
1567 _posting_events = false;
1568 ml.notify_all();
1569 }
1570 } else {
1571 remove_dead_entries(nullptr);
1572 }
1573 }
1574
1575 // support class for get_objects_with_tags
1576
1577 class TagObjectCollector : public JvmtiTagMapKeyClosure {
1578 private:
1579 JvmtiEnv* _env;
1580 JavaThread* _thread;
1581 jlong* _tags;
1582 jint _tag_count;
1583 bool _some_dead_found;
1584
1585 GrowableArray<jobject>* _object_results; // collected objects (JNI weak refs)
1586 GrowableArray<uint64_t>* _tag_results; // collected tags
1587
1588 public:
1589 TagObjectCollector(JvmtiEnv* env, const jlong* tags, jint tag_count) :
1590 _env(env),
1591 _thread(JavaThread::current()),
1592 _tags((jlong*)tags),
1593 _tag_count(tag_count),
1594 _some_dead_found(false),
1595 _object_results(new (mtServiceability) GrowableArray<jobject>(1, mtServiceability)),
1596 _tag_results(new (mtServiceability) GrowableArray<uint64_t>(1, mtServiceability)) { }
1597
1598 ~TagObjectCollector() {
1599 delete _object_results;
1600 delete _tag_results;
1601 }
1602
1603 bool some_dead_found() const { return _some_dead_found; }
1604
1605 // for each tagged object check if the tag value matches
1606 // - if it matches then we create a JNI local reference to the object
1607 // and record the reference and tag value.
1608 // Always return true so the iteration continues.
1609 bool do_entry(JvmtiTagMapKey& key, jlong& value) {
1610 for (int i = 0; i < _tag_count; i++) {
1611 if (_tags[i] == value) {
1612 // The reference in this tag map could be the only (implicitly weak)
1613 // reference to that object. If we hand it out, we need to keep it live wrt
1614 // SATB marking similar to other j.l.ref.Reference referents. This is
1615 // achieved by using a phantom load in the object() accessor.
1616 oop o = key.object();
1617 if (o == nullptr) {
1618 _some_dead_found = true;
1619 // skip this whole entry
1620 return true;
1621 }
1622 assert(o != nullptr && Universe::heap()->is_in(o), "sanity check");
1623 jobject ref = JNIHandles::make_local(_thread, o);
1624 _object_results->append(ref);
1625 _tag_results->append(value);
1626 }
1627 }
1628 return true;
1629 }
1630
1631 // return the results from the collection
1632 //
1633 jvmtiError result(jint* count_ptr, jobject** object_result_ptr, jlong** tag_result_ptr) {
1634 jvmtiError error;
1635 int count = _object_results->length();
1636 assert(count >= 0, "sanity check");
1637
1638 // if object_result_ptr is not null then allocate the result and copy
1639 // in the object references.
1640 if (object_result_ptr != nullptr) {
1641 error = _env->Allocate(count * sizeof(jobject), (unsigned char**)object_result_ptr);
1642 if (error != JVMTI_ERROR_NONE) {
1643 return error;
1644 }
1645 for (int i=0; i<count; i++) {
1646 (*object_result_ptr)[i] = _object_results->at(i);
1647 }
1648 }
1649
1650 // if tag_result_ptr is not null then allocate the result and copy
1651 // in the tag values.
1652 if (tag_result_ptr != nullptr) {
1653 error = _env->Allocate(count * sizeof(jlong), (unsigned char**)tag_result_ptr);
1654 if (error != JVMTI_ERROR_NONE) {
1655 if (object_result_ptr != nullptr) {
1656 _env->Deallocate((unsigned char*)object_result_ptr);
1657 }
1658 return error;
1659 }
1660 for (int i=0; i<count; i++) {
1661 (*tag_result_ptr)[i] = (jlong)_tag_results->at(i);
1662 }
1663 }
1664
1665 *count_ptr = count;
1666 return JVMTI_ERROR_NONE;
1667 }
1668 };
1669
1670 // return the list of objects with the specified tags
1671 jvmtiError JvmtiTagMap::get_objects_with_tags(const jlong* tags,
1672 jint count, jint* count_ptr, jobject** object_result_ptr, jlong** tag_result_ptr) {
1673
1674 // ensure flat object conversion is completed
1675 convert_flat_object_entries();
1676
1677 TagObjectCollector collector(env(), tags, count);
1678 {
1679 // iterate over all tagged objects
1680 MutexLocker ml(lock(), Mutex::_no_safepoint_check_flag);
1681 // Can't post ObjectFree events here from a JavaThread, so this
1682 // will race with the gc_notification thread in the tiny
1683 // window where the object is not marked but hasn't been notified that
1684 // it is collected yet.
1685 _hashmap->entry_iterate(&collector);
1686 }
1687 return collector.result(count_ptr, object_result_ptr, tag_result_ptr);
1688 }
1689
1690 // helper to map a jvmtiHeapReferenceKind to an old style jvmtiHeapRootKind
1691 // (not performance critical as only used for roots)
1692 static jvmtiHeapRootKind toJvmtiHeapRootKind(jvmtiHeapReferenceKind kind) {
1693 switch (kind) {
1694 case JVMTI_HEAP_REFERENCE_JNI_GLOBAL: return JVMTI_HEAP_ROOT_JNI_GLOBAL;
1695 case JVMTI_HEAP_REFERENCE_SYSTEM_CLASS: return JVMTI_HEAP_ROOT_SYSTEM_CLASS;
1696 case JVMTI_HEAP_REFERENCE_STACK_LOCAL: return JVMTI_HEAP_ROOT_STACK_LOCAL;
1697 case JVMTI_HEAP_REFERENCE_JNI_LOCAL: return JVMTI_HEAP_ROOT_JNI_LOCAL;
1698 case JVMTI_HEAP_REFERENCE_THREAD: return JVMTI_HEAP_ROOT_THREAD;
1699 case JVMTI_HEAP_REFERENCE_OTHER: return JVMTI_HEAP_ROOT_OTHER;
1700 default: ShouldNotReachHere(); return JVMTI_HEAP_ROOT_OTHER;
1701 }
1702 }
1703
1704 // Base class for all heap walk contexts. The base class maintains a flag
1705 // to indicate if the context is valid or not.
1706 class HeapWalkContext {
1707 private:
1708 bool _valid;
1709 public:
1710 HeapWalkContext(bool valid) { _valid = valid; }
1711 void invalidate() { _valid = false; }
1712 bool is_valid() const { return _valid; }
1713 };
1714
1715 // A basic heap walk context for the deprecated heap walking functions.
1716 // The context for a basic heap walk are the callbacks and fields used by
1717 // the referrer caching scheme.
1718 class BasicHeapWalkContext: public HeapWalkContext {
1719 private:
1720 jvmtiHeapRootCallback _heap_root_callback;
1721 jvmtiStackReferenceCallback _stack_ref_callback;
1722 jvmtiObjectReferenceCallback _object_ref_callback;
1723
1724 // used for caching
1725 JvmtiHeapwalkObject _last_referrer;
1726 jlong _last_referrer_tag;
1727
1728 public:
1729 BasicHeapWalkContext() : HeapWalkContext(false) { }
1730
1731 BasicHeapWalkContext(jvmtiHeapRootCallback heap_root_callback,
1732 jvmtiStackReferenceCallback stack_ref_callback,
1733 jvmtiObjectReferenceCallback object_ref_callback) :
1734 HeapWalkContext(true),
1735 _heap_root_callback(heap_root_callback),
1736 _stack_ref_callback(stack_ref_callback),
1737 _object_ref_callback(object_ref_callback),
1738 _last_referrer(),
1739 _last_referrer_tag(0) {
1740 }
1741
1742 // accessors
1743 jvmtiHeapRootCallback heap_root_callback() const { return _heap_root_callback; }
1744 jvmtiStackReferenceCallback stack_ref_callback() const { return _stack_ref_callback; }
1745 jvmtiObjectReferenceCallback object_ref_callback() const { return _object_ref_callback; }
1746
1747 JvmtiHeapwalkObject last_referrer() const { return _last_referrer; }
1748 void set_last_referrer(const JvmtiHeapwalkObject& referrer) { _last_referrer = referrer; }
1749 jlong last_referrer_tag() const { return _last_referrer_tag; }
1750 void set_last_referrer_tag(jlong value) { _last_referrer_tag = value; }
1751 };
1752
1753 // The advanced heap walk context for the FollowReferences functions.
1754 // The context is the callbacks, and the fields used for filtering.
1755 class AdvancedHeapWalkContext: public HeapWalkContext {
1756 private:
1757 jint _heap_filter;
1758 Klass* _klass_filter;
1759 const jvmtiHeapCallbacks* _heap_callbacks;
1760
1761 public:
1762 AdvancedHeapWalkContext() : HeapWalkContext(false) { }
1763
1764 AdvancedHeapWalkContext(jint heap_filter,
1765 Klass* klass_filter,
1766 const jvmtiHeapCallbacks* heap_callbacks) :
1767 HeapWalkContext(true),
1768 _heap_filter(heap_filter),
1769 _klass_filter(klass_filter),
1770 _heap_callbacks(heap_callbacks) {
1771 }
1772
1773 // accessors
1774 jint heap_filter() const { return _heap_filter; }
1775 Klass* klass_filter() const { return _klass_filter; }
1776
1777 jvmtiHeapReferenceCallback heap_reference_callback() const {
1778 return _heap_callbacks->heap_reference_callback;
1779 };
1780 jvmtiPrimitiveFieldCallback primitive_field_callback() const {
1781 return _heap_callbacks->primitive_field_callback;
1782 }
1783 jvmtiArrayPrimitiveValueCallback array_primitive_value_callback() const {
1784 return _heap_callbacks->array_primitive_value_callback;
1785 }
1786 jvmtiStringPrimitiveValueCallback string_primitive_value_callback() const {
1787 return _heap_callbacks->string_primitive_value_callback;
1788 }
1789 };
1790
1791 // The CallbackInvoker is a class with static functions that the heap walk can call
1792 // into to invoke callbacks. It works in one of two modes. The "basic" mode is
1793 // used for the deprecated IterateOverReachableObjects functions. The "advanced"
1794 // mode is for the newer FollowReferences function which supports a lot of
1795 // additional callbacks.
1796 class CallbackInvoker : AllStatic {
1797 private:
1798 // heap walk styles
1799 enum { basic, advanced };
1800 static int _heap_walk_type;
1801 static bool is_basic_heap_walk() { return _heap_walk_type == basic; }
1802 static bool is_advanced_heap_walk() { return _heap_walk_type == advanced; }
1803
1804 // context for basic style heap walk
1805 static BasicHeapWalkContext _basic_context;
1806 static BasicHeapWalkContext* basic_context() {
1807 assert(_basic_context.is_valid(), "invalid");
1808 return &_basic_context;
1809 }
1810
1811 // context for advanced style heap walk
1812 static AdvancedHeapWalkContext _advanced_context;
1813 static AdvancedHeapWalkContext* advanced_context() {
1814 assert(_advanced_context.is_valid(), "invalid");
1815 return &_advanced_context;
1816 }
1817
1818 // context needed for all heap walks
1819 static JvmtiTagMap* _tag_map;
1820 static const void* _user_data;
1821 static JvmtiHeapwalkVisitStack* _visit_stack;
1822
1823 // accessors
1824 static JvmtiTagMap* tag_map() { return _tag_map; }
1825 static const void* user_data() { return _user_data; }
1826 static JvmtiHeapwalkVisitStack* visit_stack() { return _visit_stack; }
1827
1828 // if the object hasn't been visited then push it onto the visit stack
1829 // so that it will be visited later
1830 static inline bool check_for_visit(const JvmtiHeapwalkObject&obj) {
1831 visit_stack()->check_for_visit(obj);
1832 return true;
1833 }
1834
1835 // return element count if the obj is array, -1 otherwise
1836 static jint get_array_length(const JvmtiHeapwalkObject& obj) {
1837 if (!obj.klass()->is_array_klass()) {
1838 return -1;
1839 }
1840 assert(!obj.is_flat(), "array cannot be flat");
1841 return (jint)arrayOop(obj.obj())->length();
1842 }
1843
1844 // invoke basic style callbacks
1845 static inline bool invoke_basic_heap_root_callback
1846 (jvmtiHeapRootKind root_kind, const JvmtiHeapwalkObject& obj);
1847 static inline bool invoke_basic_stack_ref_callback
1848 (jvmtiHeapRootKind root_kind, jlong thread_tag, jint depth, jmethodID method,
1849 int slot, const JvmtiHeapwalkObject& obj);
1850 static inline bool invoke_basic_object_reference_callback
1851 (jvmtiObjectReferenceKind ref_kind, const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree, jint index);
1852
1853 // invoke advanced style callbacks
1854 static inline bool invoke_advanced_heap_root_callback
1855 (jvmtiHeapReferenceKind ref_kind, const JvmtiHeapwalkObject& obj);
1856 static inline bool invoke_advanced_stack_ref_callback
1857 (jvmtiHeapReferenceKind ref_kind, jlong thread_tag, jlong tid, int depth,
1858 jmethodID method, jlocation bci, jint slot, const JvmtiHeapwalkObject& obj);
1859 static inline bool invoke_advanced_object_reference_callback
1860 (jvmtiHeapReferenceKind ref_kind, const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree, jint index);
1861
1862 // used to report the value of primitive fields
1863 static inline bool report_primitive_field
1864 (jvmtiHeapReferenceKind ref_kind, const JvmtiHeapwalkObject& obj, jint index, address addr, char type);
1865
1866 public:
1867 // initialize for basic mode
1868 static void initialize_for_basic_heap_walk(JvmtiTagMap* tag_map,
1869 const void* user_data,
1870 BasicHeapWalkContext context,
1871 JvmtiHeapwalkVisitStack* visit_stack);
1872
1873 // initialize for advanced mode
1874 static void initialize_for_advanced_heap_walk(JvmtiTagMap* tag_map,
1875 const void* user_data,
1876 AdvancedHeapWalkContext context,
1877 JvmtiHeapwalkVisitStack* visit_stack);
1878
1879 // functions to report roots
1880 static inline bool report_simple_root(jvmtiHeapReferenceKind kind, const JvmtiHeapwalkObject& o);
1881 static inline bool report_jni_local_root(jlong thread_tag, jlong tid, jint depth,
1882 jmethodID m, const JvmtiHeapwalkObject& o);
1883 static inline bool report_stack_ref_root(jlong thread_tag, jlong tid, jint depth,
1884 jmethodID method, jlocation bci, jint slot, const JvmtiHeapwalkObject& o);
1885
1886 // functions to report references
1887 static inline bool report_array_element_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree, jint index);
1888 static inline bool report_class_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree);
1889 static inline bool report_class_loader_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree);
1890 static inline bool report_signers_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree);
1891 static inline bool report_protection_domain_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree);
1892 static inline bool report_superclass_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree);
1893 static inline bool report_interface_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree);
1894 static inline bool report_static_field_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree, jint slot);
1895 static inline bool report_field_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree, jint slot);
1896 static inline bool report_constant_pool_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree, jint index);
1897 static inline bool report_primitive_array_values(const JvmtiHeapwalkObject& array);
1898 static inline bool report_string_value(const JvmtiHeapwalkObject& str);
1899 static inline bool report_primitive_instance_field(const JvmtiHeapwalkObject& o, jint index, address value, char type);
1900 static inline bool report_primitive_static_field(const JvmtiHeapwalkObject& o, jint index, address value, char type);
1901 };
1902
1903 // statics
1904 int CallbackInvoker::_heap_walk_type;
1905 BasicHeapWalkContext CallbackInvoker::_basic_context;
1906 AdvancedHeapWalkContext CallbackInvoker::_advanced_context;
1907 JvmtiTagMap* CallbackInvoker::_tag_map;
1908 const void* CallbackInvoker::_user_data;
1909 JvmtiHeapwalkVisitStack* CallbackInvoker::_visit_stack;
1910
1911 // initialize for basic heap walk (IterateOverReachableObjects et al)
1912 void CallbackInvoker::initialize_for_basic_heap_walk(JvmtiTagMap* tag_map,
1913 const void* user_data,
1914 BasicHeapWalkContext context,
1915 JvmtiHeapwalkVisitStack* visit_stack) {
1916 _tag_map = tag_map;
1917 _user_data = user_data;
1918 _basic_context = context;
1919 _advanced_context.invalidate(); // will trigger assertion if used
1920 _heap_walk_type = basic;
1921 _visit_stack = visit_stack;
1922 }
1923
1924 // initialize for advanced heap walk (FollowReferences)
1925 void CallbackInvoker::initialize_for_advanced_heap_walk(JvmtiTagMap* tag_map,
1926 const void* user_data,
1927 AdvancedHeapWalkContext context,
1928 JvmtiHeapwalkVisitStack* visit_stack) {
1929 _tag_map = tag_map;
1930 _user_data = user_data;
1931 _advanced_context = context;
1932 _basic_context.invalidate(); // will trigger assertion if used
1933 _heap_walk_type = advanced;
1934 _visit_stack = visit_stack;
1935 }
1936
1937
1938 // invoke basic style heap root callback
1939 inline bool CallbackInvoker::invoke_basic_heap_root_callback(jvmtiHeapRootKind root_kind, const JvmtiHeapwalkObject& obj) {
1940 // if we heap roots should be reported
1941 jvmtiHeapRootCallback cb = basic_context()->heap_root_callback();
1942 if (cb == nullptr) {
1943 return check_for_visit(obj);
1944 }
1945
1946 CallbackWrapper wrapper(tag_map(), obj);
1947 jvmtiIterationControl control = (*cb)(root_kind,
1948 wrapper.klass_tag(),
1949 wrapper.obj_size(),
1950 wrapper.obj_tag_p(),
1951 (void*)user_data());
1952 // push root to visit stack when following references
1953 if (control == JVMTI_ITERATION_CONTINUE &&
1954 basic_context()->object_ref_callback() != nullptr) {
1955 visit_stack()->push(obj);
1956 }
1957 return control != JVMTI_ITERATION_ABORT;
1958 }
1959
1960 // invoke basic style stack ref callback
1961 inline bool CallbackInvoker::invoke_basic_stack_ref_callback(jvmtiHeapRootKind root_kind,
1962 jlong thread_tag,
1963 jint depth,
1964 jmethodID method,
1965 int slot,
1966 const JvmtiHeapwalkObject& obj) {
1967 // if we stack refs should be reported
1968 jvmtiStackReferenceCallback cb = basic_context()->stack_ref_callback();
1969 if (cb == nullptr) {
1970 return check_for_visit(obj);
1971 }
1972
1973 CallbackWrapper wrapper(tag_map(), obj);
1974 jvmtiIterationControl control = (*cb)(root_kind,
1975 wrapper.klass_tag(),
1976 wrapper.obj_size(),
1977 wrapper.obj_tag_p(),
1978 thread_tag,
1979 depth,
1980 method,
1981 slot,
1982 (void*)user_data());
1983 // push root to visit stack when following references
1984 if (control == JVMTI_ITERATION_CONTINUE &&
1985 basic_context()->object_ref_callback() != nullptr) {
1986 visit_stack()->push(obj);
1987 }
1988 return control != JVMTI_ITERATION_ABORT;
1989 }
1990
1991 // invoke basic style object reference callback
1992 inline bool CallbackInvoker::invoke_basic_object_reference_callback(jvmtiObjectReferenceKind ref_kind,
1993 const JvmtiHeapwalkObject& referrer,
1994 const JvmtiHeapwalkObject& referree,
1995 jint index) {
1996
1997 BasicHeapWalkContext* context = basic_context();
1998
1999 // callback requires the referrer's tag. If it's the same referrer
2000 // as the last call then we use the cached value.
2001 jlong referrer_tag;
2002 if (referrer == context->last_referrer()) {
2003 referrer_tag = context->last_referrer_tag();
2004 } else {
2005 referrer_tag = tag_map()->find(referrer);
2006 }
2007
2008 // do the callback
2009 CallbackWrapper wrapper(tag_map(), referree);
2010 jvmtiObjectReferenceCallback cb = context->object_ref_callback();
2011 jvmtiIterationControl control = (*cb)(ref_kind,
2012 wrapper.klass_tag(),
2013 wrapper.obj_size(),
2014 wrapper.obj_tag_p(),
2015 referrer_tag,
2016 index,
2017 (void*)user_data());
2018
2019 // record referrer and referrer tag. For self-references record the
2020 // tag value from the callback as this might differ from referrer_tag.
2021 context->set_last_referrer(referrer);
2022 if (referrer == referree) {
2023 context->set_last_referrer_tag(*wrapper.obj_tag_p());
2024 } else {
2025 context->set_last_referrer_tag(referrer_tag);
2026 }
2027
2028 if (control == JVMTI_ITERATION_CONTINUE) {
2029 return check_for_visit(referree);
2030 } else {
2031 return control != JVMTI_ITERATION_ABORT;
2032 }
2033 }
2034
2035 // invoke advanced style heap root callback
2036 inline bool CallbackInvoker::invoke_advanced_heap_root_callback(jvmtiHeapReferenceKind ref_kind,
2037 const JvmtiHeapwalkObject& obj) {
2038 AdvancedHeapWalkContext* context = advanced_context();
2039
2040 // check that callback is provided
2041 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
2042 if (cb == nullptr) {
2043 return check_for_visit(obj);
2044 }
2045
2046 // apply class filter
2047 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2048 return check_for_visit(obj);
2049 }
2050
2051 // setup the callback wrapper
2052 CallbackWrapper wrapper(tag_map(), obj);
2053
2054 // apply tag filter
2055 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2056 wrapper.klass_tag(),
2057 context->heap_filter())) {
2058 return check_for_visit(obj);
2059 }
2060
2061 // for arrays we need the length, otherwise -1
2062 jint len = get_array_length(obj);
2063
2064 // invoke the callback
2065 jint res = (*cb)(ref_kind,
2066 nullptr, // referrer info
2067 wrapper.klass_tag(),
2068 0, // referrer_class_tag is 0 for heap root
2069 wrapper.obj_size(),
2070 wrapper.obj_tag_p(),
2071 nullptr, // referrer_tag_p
2072 len,
2073 (void*)user_data());
2074 if (res & JVMTI_VISIT_ABORT) {
2075 return false;// referrer class tag
2076 }
2077 if (res & JVMTI_VISIT_OBJECTS) {
2078 check_for_visit(obj);
2079 }
2080 return true;
2081 }
2082
2083 // report a reference from a thread stack to an object
2084 inline bool CallbackInvoker::invoke_advanced_stack_ref_callback(jvmtiHeapReferenceKind ref_kind,
2085 jlong thread_tag,
2086 jlong tid,
2087 int depth,
2088 jmethodID method,
2089 jlocation bci,
2090 jint slot,
2091 const JvmtiHeapwalkObject& obj) {
2092 AdvancedHeapWalkContext* context = advanced_context();
2093
2094 // check that callback is provider
2095 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
2096 if (cb == nullptr) {
2097 return check_for_visit(obj);
2098 }
2099
2100 // apply class filter
2101 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2102 return check_for_visit(obj);
2103 }
2104
2105 // setup the callback wrapper
2106 CallbackWrapper wrapper(tag_map(), obj);
2107
2108 // apply tag filter
2109 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2110 wrapper.klass_tag(),
2111 context->heap_filter())) {
2112 return check_for_visit(obj);
2113 }
2114
2115 // setup the referrer info
2116 jvmtiHeapReferenceInfo reference_info;
2117 reference_info.stack_local.thread_tag = thread_tag;
2118 reference_info.stack_local.thread_id = tid;
2119 reference_info.stack_local.depth = depth;
2120 reference_info.stack_local.method = method;
2121 reference_info.stack_local.location = bci;
2122 reference_info.stack_local.slot = slot;
2123
2124 // for arrays we need the length, otherwise -1
2125 jint len = get_array_length(obj);
2126
2127 // call into the agent
2128 int res = (*cb)(ref_kind,
2129 &reference_info,
2130 wrapper.klass_tag(),
2131 0, // referrer_class_tag is 0 for heap root (stack)
2132 wrapper.obj_size(),
2133 wrapper.obj_tag_p(),
2134 nullptr, // referrer_tag is 0 for root
2135 len,
2136 (void*)user_data());
2137
2138 if (res & JVMTI_VISIT_ABORT) {
2139 return false;
2140 }
2141 if (res & JVMTI_VISIT_OBJECTS) {
2142 check_for_visit(obj);
2143 }
2144 return true;
2145 }
2146
2147 // This mask is used to pass reference_info to a jvmtiHeapReferenceCallback
2148 // only for ref_kinds defined by the JVM TI spec. Otherwise, null is passed.
2149 #define REF_INFO_MASK ((1 << JVMTI_HEAP_REFERENCE_FIELD) \
2150 | (1 << JVMTI_HEAP_REFERENCE_STATIC_FIELD) \
2151 | (1 << JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT) \
2152 | (1 << JVMTI_HEAP_REFERENCE_CONSTANT_POOL) \
2153 | (1 << JVMTI_HEAP_REFERENCE_STACK_LOCAL) \
2154 | (1 << JVMTI_HEAP_REFERENCE_JNI_LOCAL))
2155
2156 // invoke the object reference callback to report a reference
2157 inline bool CallbackInvoker::invoke_advanced_object_reference_callback(jvmtiHeapReferenceKind ref_kind,
2158 const JvmtiHeapwalkObject& referrer,
2159 const JvmtiHeapwalkObject& obj,
2160 jint index)
2161 {
2162 // field index is only valid field in reference_info
2163 static jvmtiHeapReferenceInfo reference_info = { 0 };
2164
2165 AdvancedHeapWalkContext* context = advanced_context();
2166
2167 // check that callback is provider
2168 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
2169 if (cb == nullptr) {
2170 return check_for_visit(obj);
2171 }
2172
2173 // apply class filter
2174 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2175 return check_for_visit(obj);
2176 }
2177
2178 // setup the callback wrapper
2179 TwoOopCallbackWrapper wrapper(tag_map(), referrer, obj);
2180
2181 // apply tag filter
2182 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2183 wrapper.klass_tag(),
2184 context->heap_filter())) {
2185 return check_for_visit(obj);
2186 }
2187
2188 // field index is only valid field in reference_info
2189 reference_info.field.index = index;
2190
2191 // for arrays we need the length, otherwise -1
2192 jint len = get_array_length(obj);
2193
2194 // invoke the callback
2195 int res = (*cb)(ref_kind,
2196 (REF_INFO_MASK & (1 << ref_kind)) ? &reference_info : nullptr,
2197 wrapper.klass_tag(),
2198 wrapper.referrer_klass_tag(),
2199 wrapper.obj_size(),
2200 wrapper.obj_tag_p(),
2201 wrapper.referrer_tag_p(),
2202 len,
2203 (void*)user_data());
2204
2205 if (res & JVMTI_VISIT_ABORT) {
2206 return false;
2207 }
2208 if (res & JVMTI_VISIT_OBJECTS) {
2209 check_for_visit(obj);
2210 }
2211 return true;
2212 }
2213
2214 // report a "simple root"
2215 inline bool CallbackInvoker::report_simple_root(jvmtiHeapReferenceKind kind, const JvmtiHeapwalkObject& obj) {
2216 assert(kind != JVMTI_HEAP_REFERENCE_STACK_LOCAL &&
2217 kind != JVMTI_HEAP_REFERENCE_JNI_LOCAL, "not a simple root");
2218
2219 if (is_basic_heap_walk()) {
2220 // map to old style root kind
2221 jvmtiHeapRootKind root_kind = toJvmtiHeapRootKind(kind);
2222 return invoke_basic_heap_root_callback(root_kind, obj);
2223 } else {
2224 assert(is_advanced_heap_walk(), "wrong heap walk type");
2225 return invoke_advanced_heap_root_callback(kind, obj);
2226 }
2227 }
2228
2229
2230 // invoke the primitive array values
2231 inline bool CallbackInvoker::report_primitive_array_values(const JvmtiHeapwalkObject& obj) {
2232 assert(obj.klass()->is_typeArray_klass(), "not a primitive array");
2233
2234 AdvancedHeapWalkContext* context = advanced_context();
2235 assert(context->array_primitive_value_callback() != nullptr, "no callback");
2236
2237 // apply class filter
2238 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2239 return true;
2240 }
2241
2242 CallbackWrapper wrapper(tag_map(), obj);
2243
2244 // apply tag filter
2245 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2246 wrapper.klass_tag(),
2247 context->heap_filter())) {
2248 return true;
2249 }
2250
2251 // invoke the callback
2252 int res = invoke_array_primitive_value_callback(context->array_primitive_value_callback(),
2253 &wrapper,
2254 obj,
2255 (void*)user_data());
2256 return (!(res & JVMTI_VISIT_ABORT));
2257 }
2258
2259 // invoke the string value callback
2260 inline bool CallbackInvoker::report_string_value(const JvmtiHeapwalkObject& str) {
2261 assert(str.klass() == vmClasses::String_klass(), "not a string");
2262
2263 AdvancedHeapWalkContext* context = advanced_context();
2264 assert(context->string_primitive_value_callback() != nullptr, "no callback");
2265
2266 // apply class filter
2267 if (is_filtered_by_klass_filter(str, context->klass_filter())) {
2268 return true;
2269 }
2270
2271 CallbackWrapper wrapper(tag_map(), str);
2272
2273 // apply tag filter
2274 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2275 wrapper.klass_tag(),
2276 context->heap_filter())) {
2277 return true;
2278 }
2279
2280 // invoke the callback
2281 int res = invoke_string_value_callback(context->string_primitive_value_callback(),
2282 &wrapper,
2283 str,
2284 (void*)user_data());
2285 return (!(res & JVMTI_VISIT_ABORT));
2286 }
2287
2288 // invoke the primitive field callback
2289 inline bool CallbackInvoker::report_primitive_field(jvmtiHeapReferenceKind ref_kind,
2290 const JvmtiHeapwalkObject& obj,
2291 jint index,
2292 address addr,
2293 char type)
2294 {
2295 // for primitive fields only the index will be set
2296 static jvmtiHeapReferenceInfo reference_info = { 0 };
2297
2298 AdvancedHeapWalkContext* context = advanced_context();
2299 assert(context->primitive_field_callback() != nullptr, "no callback");
2300
2301 // apply class filter
2302 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2303 return true;
2304 }
2305
2306 CallbackWrapper wrapper(tag_map(), obj);
2307
2308 // apply tag filter
2309 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2310 wrapper.klass_tag(),
2311 context->heap_filter())) {
2312 return true;
2313 }
2314
2315 // the field index in the referrer
2316 reference_info.field.index = index;
2317
2318 // map the type
2319 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
2320
2321 // setup the jvalue
2322 jvalue value;
2323 copy_to_jvalue(&value, addr, value_type);
2324
2325 jvmtiPrimitiveFieldCallback cb = context->primitive_field_callback();
2326 int res = (*cb)(ref_kind,
2327 &reference_info,
2328 wrapper.klass_tag(),
2329 wrapper.obj_tag_p(),
2330 value,
2331 value_type,
2332 (void*)user_data());
2333 return (!(res & JVMTI_VISIT_ABORT));
2334 }
2335
2336
2337 // instance field
2338 inline bool CallbackInvoker::report_primitive_instance_field(const JvmtiHeapwalkObject& obj,
2339 jint index,
2340 address value,
2341 char type) {
2342 return report_primitive_field(JVMTI_HEAP_REFERENCE_FIELD,
2343 obj,
2344 index,
2345 value,
2346 type);
2347 }
2348
2349 // static field
2350 inline bool CallbackInvoker::report_primitive_static_field(const JvmtiHeapwalkObject& obj,
2351 jint index,
2352 address value,
2353 char type) {
2354 return report_primitive_field(JVMTI_HEAP_REFERENCE_STATIC_FIELD,
2355 obj,
2356 index,
2357 value,
2358 type);
2359 }
2360
2361 // report a JNI local (root object) to the profiler
2362 inline bool CallbackInvoker::report_jni_local_root(jlong thread_tag, jlong tid, jint depth, jmethodID m, const JvmtiHeapwalkObject& obj) {
2363 if (is_basic_heap_walk()) {
2364 return invoke_basic_stack_ref_callback(JVMTI_HEAP_ROOT_JNI_LOCAL,
2365 thread_tag,
2366 depth,
2367 m,
2368 -1,
2369 obj);
2370 } else {
2371 return invoke_advanced_stack_ref_callback(JVMTI_HEAP_REFERENCE_JNI_LOCAL,
2372 thread_tag, tid,
2373 depth,
2374 m,
2375 (jlocation)-1,
2376 -1,
2377 obj);
2378 }
2379 }
2380
2381
2382 // report a local (stack reference, root object)
2383 inline bool CallbackInvoker::report_stack_ref_root(jlong thread_tag,
2384 jlong tid,
2385 jint depth,
2386 jmethodID method,
2387 jlocation bci,
2388 jint slot,
2389 const JvmtiHeapwalkObject& obj) {
2390 if (is_basic_heap_walk()) {
2391 return invoke_basic_stack_ref_callback(JVMTI_HEAP_ROOT_STACK_LOCAL,
2392 thread_tag,
2393 depth,
2394 method,
2395 slot,
2396 obj);
2397 } else {
2398 return invoke_advanced_stack_ref_callback(JVMTI_HEAP_REFERENCE_STACK_LOCAL,
2399 thread_tag,
2400 tid,
2401 depth,
2402 method,
2403 bci,
2404 slot,
2405 obj);
2406 }
2407 }
2408
2409 // report an object referencing a class.
2410 inline bool CallbackInvoker::report_class_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree) {
2411 if (is_basic_heap_walk()) {
2412 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS, referrer, referree, -1);
2413 } else {
2414 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CLASS, referrer, referree, -1);
2415 }
2416 }
2417
2418 // report a class referencing its class loader.
2419 inline bool CallbackInvoker::report_class_loader_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree) {
2420 if (is_basic_heap_walk()) {
2421 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS_LOADER, referrer, referree, -1);
2422 } else {
2423 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CLASS_LOADER, referrer, referree, -1);
2424 }
2425 }
2426
2427 // report a class referencing its signers.
2428 inline bool CallbackInvoker::report_signers_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree) {
2429 if (is_basic_heap_walk()) {
2430 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_SIGNERS, referrer, referree, -1);
2431 } else {
2432 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_SIGNERS, referrer, referree, -1);
2433 }
2434 }
2435
2436 // report a class referencing its protection domain..
2437 inline bool CallbackInvoker::report_protection_domain_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree) {
2438 if (is_basic_heap_walk()) {
2439 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_PROTECTION_DOMAIN, referrer, referree, -1);
2440 } else {
2441 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_PROTECTION_DOMAIN, referrer, referree, -1);
2442 }
2443 }
2444
2445 // report a class referencing its superclass.
2446 inline bool CallbackInvoker::report_superclass_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree) {
2447 if (is_basic_heap_walk()) {
2448 // Send this to be consistent with past implementation
2449 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS, referrer, referree, -1);
2450 } else {
2451 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_SUPERCLASS, referrer, referree, -1);
2452 }
2453 }
2454
2455 // report a class referencing one of its interfaces.
2456 inline bool CallbackInvoker::report_interface_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree) {
2457 if (is_basic_heap_walk()) {
2458 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_INTERFACE, referrer, referree, -1);
2459 } else {
2460 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_INTERFACE, referrer, referree, -1);
2461 }
2462 }
2463
2464 // report a class referencing one of its static fields.
2465 inline bool CallbackInvoker::report_static_field_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree, jint slot) {
2466 if (is_basic_heap_walk()) {
2467 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_STATIC_FIELD, referrer, referree, slot);
2468 } else {
2469 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_STATIC_FIELD, referrer, referree, slot);
2470 }
2471 }
2472
2473 // report an array referencing an element object
2474 inline bool CallbackInvoker::report_array_element_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree, jint index) {
2475 if (is_basic_heap_walk()) {
2476 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_ARRAY_ELEMENT, referrer, referree, index);
2477 } else {
2478 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT, referrer, referree, index);
2479 }
2480 }
2481
2482 // report an object referencing an instance field object
2483 inline bool CallbackInvoker::report_field_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree, jint slot) {
2484 if (is_basic_heap_walk()) {
2485 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_FIELD, referrer, referree, slot);
2486 } else {
2487 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_FIELD, referrer, referree, slot);
2488 }
2489 }
2490
2491 // report an array referencing an element object
2492 inline bool CallbackInvoker::report_constant_pool_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree, jint index) {
2493 if (is_basic_heap_walk()) {
2494 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CONSTANT_POOL, referrer, referree, index);
2495 } else {
2496 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CONSTANT_POOL, referrer, referree, index);
2497 }
2498 }
2499
2500 // A supporting closure used to process simple roots
2501 class SimpleRootsClosure : public OopClosure {
2502 private:
2503 jvmtiHeapReferenceKind _kind;
2504 bool _continue;
2505
2506 jvmtiHeapReferenceKind root_kind() { return _kind; }
2507
2508 public:
2509 void set_kind(jvmtiHeapReferenceKind kind) {
2510 _kind = kind;
2511 _continue = true;
2512 }
2513
2514 inline bool stopped() {
2515 return !_continue;
2516 }
2517
2518 void do_oop(oop* obj_p) {
2519 // iteration has terminated
2520 if (stopped()) {
2521 return;
2522 }
2523
2524 oop o = NativeAccess<AS_NO_KEEPALIVE>::oop_load(obj_p);
2525 // ignore null
2526 if (o == nullptr) {
2527 return;
2528 }
2529
2530 assert(Universe::heap()->is_in(o), "should be impossible");
2531
2532 jvmtiHeapReferenceKind kind = root_kind();
2533
2534 // invoke the callback
2535 _continue = CallbackInvoker::report_simple_root(kind, o);
2536
2537 }
2538 virtual void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
2539 };
2540
2541 // A supporting closure used to process ClassLoaderData roots.
2542 class CLDRootsClosure: public OopClosure {
2543 private:
2544 bool _continue;
2545 public:
2546 CLDRootsClosure(): _continue(true) {}
2547
2548 inline bool stopped() {
2549 return !_continue;
2550 }
2551
2552 void do_oop(oop* obj_p) {
2553 if (stopped()) {
2554 return;
2555 }
2556
2557 oop o = NativeAccess<AS_NO_KEEPALIVE>::oop_load(obj_p);
2558 // ignore null
2559 if (o == nullptr) {
2560 return;
2561 }
2562
2563 jvmtiHeapReferenceKind kind = JVMTI_HEAP_REFERENCE_OTHER;
2564 if (o->klass() == vmClasses::Class_klass()) {
2565 kind = JVMTI_HEAP_REFERENCE_SYSTEM_CLASS;
2566 }
2567
2568 // invoke the callback
2569 _continue = CallbackInvoker::report_simple_root(kind, o);
2570 }
2571 virtual void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
2572 };
2573
2574 // A supporting closure used to process JNI locals
2575 class JNILocalRootsClosure : public OopClosure {
2576 private:
2577 jlong _thread_tag;
2578 jlong _tid;
2579 jint _depth;
2580 jmethodID _method;
2581 bool _continue;
2582 public:
2583 void set_context(jlong thread_tag, jlong tid, jint depth, jmethodID method) {
2584 _thread_tag = thread_tag;
2585 _tid = tid;
2586 _depth = depth;
2587 _method = method;
2588 _continue = true;
2589 }
2590
2591 inline bool stopped() {
2592 return !_continue;
2593 }
2594
2595 void do_oop(oop* obj_p) {
2596 // iteration has terminated
2597 if (stopped()) {
2598 return;
2599 }
2600
2601 oop o = *obj_p;
2602 // ignore null
2603 if (o == nullptr) {
2604 return;
2605 }
2606
2607 // invoke the callback
2608 _continue = CallbackInvoker::report_jni_local_root(_thread_tag, _tid, _depth, _method, o);
2609 }
2610 virtual void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
2611 };
2612
2613 // Helper class to collect/report stack references.
2614 class StackRefCollector {
2615 private:
2616 JvmtiTagMap* _tag_map;
2617 JNILocalRootsClosure* _blk;
2618 // java_thread is needed only to report JNI local on top native frame;
2619 // I.e. it's required only for platform/carrier threads or mounted virtual threads.
2620 JavaThread* _java_thread;
2621
2622 oop _threadObj;
2623 jlong _thread_tag;
2624 jlong _tid;
2625
2626 bool _is_top_frame;
2627 int _depth;
2628 frame* _last_entry_frame;
2629
2630 bool report_java_stack_refs(StackValueCollection* values, jmethodID method, jlocation bci, jint slot_offset);
2631 bool report_native_stack_refs(jmethodID method);
2632
2633 public:
2634 StackRefCollector(JvmtiTagMap* tag_map, JNILocalRootsClosure* blk, JavaThread* java_thread)
2635 : _tag_map(tag_map), _blk(blk), _java_thread(java_thread),
2636 _threadObj(nullptr), _thread_tag(0), _tid(0),
2637 _is_top_frame(true), _depth(0), _last_entry_frame(nullptr)
2638 {
2639 }
2640
2641 bool set_thread(oop o);
2642 // Sets the thread and reports the reference to it with the specified kind.
2643 bool set_thread(jvmtiHeapReferenceKind kind, oop o);
2644
2645 bool do_frame(vframe* vf);
2646 // Handles frames until vf->sender() is null.
2647 bool process_frames(vframe* vf);
2648 };
2649
2650 bool StackRefCollector::set_thread(oop o) {
2651 _threadObj = o;
2652 _thread_tag = _tag_map->find(_threadObj);
2653 _tid = java_lang_Thread::thread_id(_threadObj);
2654
2655 _is_top_frame = true;
2656 _depth = 0;
2657 _last_entry_frame = nullptr;
2658
2659 return true;
2660 }
2661
2662 bool StackRefCollector::set_thread(jvmtiHeapReferenceKind kind, oop o) {
2663 return set_thread(o)
2664 && CallbackInvoker::report_simple_root(kind, _threadObj);
2665 }
2666
2667 bool StackRefCollector::report_java_stack_refs(StackValueCollection* values, jmethodID method, jlocation bci, jint slot_offset) {
2668 for (int index = 0; index < values->size(); index++) {
2669 if (values->at(index)->type() == T_OBJECT) {
2670 oop obj = values->obj_at(index)();
2671 if (obj == nullptr) {
2672 continue;
2673 }
2674 // stack reference
2675 if (!CallbackInvoker::report_stack_ref_root(_thread_tag, _tid, _depth, method,
2676 bci, slot_offset + index, obj)) {
2677 return false;
2678 }
2679 }
2680 }
2681 return true;
2682 }
2683
2684 bool StackRefCollector::report_native_stack_refs(jmethodID method) {
2685 _blk->set_context(_thread_tag, _tid, _depth, method);
2686 if (_is_top_frame) {
2687 // JNI locals for the top frame.
2688 if (_java_thread != nullptr) {
2689 _java_thread->active_handles()->oops_do(_blk);
2690 if (_blk->stopped()) {
2691 return false;
2692 }
2693 }
2694 } else {
2695 if (_last_entry_frame != nullptr) {
2696 // JNI locals for the entry frame.
2697 assert(_last_entry_frame->is_entry_frame(), "checking");
2698 _last_entry_frame->entry_frame_call_wrapper()->handles()->oops_do(_blk);
2699 if (_blk->stopped()) {
2700 return false;
2701 }
2702 }
2703 }
2704 return true;
2705 }
2706
2707 bool StackRefCollector::do_frame(vframe* vf) {
2708 if (vf->is_java_frame()) {
2709 // java frame (interpreted, compiled, ...)
2710 javaVFrame* jvf = javaVFrame::cast(vf);
2711
2712 jmethodID method = jvf->method()->jmethod_id();
2713
2714 if (!(jvf->method()->is_native())) {
2715 jlocation bci = (jlocation)jvf->bci();
2716 StackValueCollection* locals = jvf->locals();
2717 if (!report_java_stack_refs(locals, method, bci, 0)) {
2718 return false;
2719 }
2720 if (!report_java_stack_refs(jvf->expressions(), method, bci, locals->size())) {
2721 return false;
2722 }
2723
2724 // Follow oops from compiled nmethod.
2725 if (jvf->cb() != nullptr && jvf->cb()->is_nmethod()) {
2726 _blk->set_context(_thread_tag, _tid, _depth, method);
2727 // Need to apply load barriers for unmounted vthreads.
2728 nmethod* nm = jvf->cb()->as_nmethod();
2729 nm->run_nmethod_entry_barrier();
2730 nm->oops_do(_blk);
2731 if (_blk->stopped()) {
2732 return false;
2733 }
2734 }
2735 } else {
2736 // native frame
2737 if (!report_native_stack_refs(method)) {
2738 return false;
2739 }
2740 }
2741 _last_entry_frame = nullptr;
2742 _depth++;
2743 } else {
2744 // externalVFrame - for an entry frame then we report the JNI locals
2745 // when we find the corresponding javaVFrame
2746 frame* fr = vf->frame_pointer();
2747 assert(fr != nullptr, "sanity check");
2748 if (fr->is_entry_frame()) {
2749 _last_entry_frame = fr;
2750 }
2751 }
2752
2753 _is_top_frame = false;
2754
2755 return true;
2756 }
2757
2758 bool StackRefCollector::process_frames(vframe* vf) {
2759 while (vf != nullptr) {
2760 if (!do_frame(vf)) {
2761 return false;
2762 }
2763 vf = vf->sender();
2764 }
2765 return true;
2766 }
2767
2768
2769 // A VM operation to iterate over objects that are reachable from
2770 // a set of roots or an initial object.
2771 //
2772 // For VM_HeapWalkOperation the set of roots used is :-
2773 //
2774 // - All JNI global references
2775 // - All inflated monitors
2776 // - All classes loaded by the boot class loader (or all classes
2777 // in the event that class unloading is disabled)
2778 // - All java threads
2779 // - For each java thread then all locals and JNI local references
2780 // on the thread's execution stack
2781 // - All visible/explainable objects from Universes::oops_do
2782 //
2783 class VM_HeapWalkOperation: public VM_Operation {
2784 private:
2785 bool _is_advanced_heap_walk; // indicates FollowReferences
2786 JvmtiTagMap* _tag_map;
2787 Handle _initial_object;
2788 JvmtiHeapwalkVisitStack _visit_stack;
2789
2790 // Dead object tags in JvmtiTagMap
2791 GrowableArray<jlong>* _dead_objects;
2792
2793 bool _following_object_refs; // are we following object references
2794
2795 bool _reporting_primitive_fields; // optional reporting
2796 bool _reporting_primitive_array_values;
2797 bool _reporting_string_values;
2798
2799 // accessors
2800 bool is_advanced_heap_walk() const { return _is_advanced_heap_walk; }
2801 JvmtiTagMap* tag_map() const { return _tag_map; }
2802 Handle initial_object() const { return _initial_object; }
2803
2804 bool is_following_references() const { return _following_object_refs; }
2805
2806 bool is_reporting_primitive_fields() const { return _reporting_primitive_fields; }
2807 bool is_reporting_primitive_array_values() const { return _reporting_primitive_array_values; }
2808 bool is_reporting_string_values() const { return _reporting_string_values; }
2809
2810 JvmtiHeapwalkVisitStack* visit_stack() { return &_visit_stack; }
2811
2812 // iterate over the various object types
2813 inline bool iterate_over_array(const JvmtiHeapwalkObject& o);
2814 inline bool iterate_over_flat_array(const JvmtiHeapwalkObject& o);
2815 inline bool iterate_over_type_array(const JvmtiHeapwalkObject& o);
2816 inline bool iterate_over_class(const JvmtiHeapwalkObject& o);
2817 inline bool iterate_over_object(const JvmtiHeapwalkObject& o);
2818
2819 // root collection
2820 inline bool collect_simple_roots();
2821 inline bool collect_stack_roots();
2822 inline bool collect_stack_refs(JavaThread* java_thread, JNILocalRootsClosure* blk);
2823 inline bool collect_vthread_stack_refs(oop vt);
2824
2825 // visit an object
2826 inline bool visit(const JvmtiHeapwalkObject& o);
2827
2828 public:
2829 VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2830 Handle initial_object,
2831 BasicHeapWalkContext callbacks,
2832 const void* user_data,
2833 GrowableArray<jlong>* objects);
2834
2835 VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2836 Handle initial_object,
2837 AdvancedHeapWalkContext callbacks,
2838 const void* user_data,
2839 GrowableArray<jlong>* objects);
2840
2841 ~VM_HeapWalkOperation();
2842
2843 VMOp_Type type() const { return VMOp_HeapWalkOperation; }
2844 void doit();
2845 };
2846
2847
2848 VM_HeapWalkOperation::VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2849 Handle initial_object,
2850 BasicHeapWalkContext callbacks,
2851 const void* user_data,
2852 GrowableArray<jlong>* objects) {
2853 _is_advanced_heap_walk = false;
2854 _tag_map = tag_map;
2855 _initial_object = initial_object;
2856 _following_object_refs = (callbacks.object_ref_callback() != nullptr);
2857 _reporting_primitive_fields = false;
2858 _reporting_primitive_array_values = false;
2859 _reporting_string_values = false;
2860 _dead_objects = objects;
2861 CallbackInvoker::initialize_for_basic_heap_walk(tag_map, user_data, callbacks, &_visit_stack);
2862 }
2863
2864 VM_HeapWalkOperation::VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2865 Handle initial_object,
2866 AdvancedHeapWalkContext callbacks,
2867 const void* user_data,
2868 GrowableArray<jlong>* objects) {
2869 _is_advanced_heap_walk = true;
2870 _tag_map = tag_map;
2871 _initial_object = initial_object;
2872 _following_object_refs = true;
2873 _reporting_primitive_fields = (callbacks.primitive_field_callback() != nullptr);;
2874 _reporting_primitive_array_values = (callbacks.array_primitive_value_callback() != nullptr);;
2875 _reporting_string_values = (callbacks.string_primitive_value_callback() != nullptr);;
2876 _dead_objects = objects;
2877 CallbackInvoker::initialize_for_advanced_heap_walk(tag_map, user_data, callbacks, &_visit_stack);
2878 }
2879
2880 VM_HeapWalkOperation::~VM_HeapWalkOperation() {
2881 }
2882
2883 // an array references its class and has a reference to
2884 // each element in the array
2885 inline bool VM_HeapWalkOperation::iterate_over_array(const JvmtiHeapwalkObject& o) {
2886 assert(!o.is_flat(), "Array object cannot be flattened");
2887 refArrayOop array = oop_cast<refArrayOop>(o.obj());
2888
2889 // array reference to its class
2890 oop mirror = array->klass()->java_mirror();
2891 if (!CallbackInvoker::report_class_reference(o, mirror)) {
2892 return false;
2893 }
2894
2895 // iterate over the array and report each reference to a
2896 // non-null element
2897 for (int index=0; index<array->length(); index++) {
2898 oop elem = array->obj_at(index);
2899 if (elem == nullptr) {
2900 continue;
2901 }
2902
2903 // report the array reference o[index] = elem
2904 if (!CallbackInvoker::report_array_element_reference(o, elem, index)) {
2905 return false;
2906 }
2907 }
2908 return true;
2909 }
2910
2911 // similar to iterate_over_array(), but itrates over flat array
2912 inline bool VM_HeapWalkOperation::iterate_over_flat_array(const JvmtiHeapwalkObject& o) {
2913 assert(!o.is_flat(), "Array object cannot be flattened");
2914 flatArrayOop array = flatArrayOop(o.obj());
2915 FlatArrayKlass* fak = array->klass();
2916 InlineKlass* vk = fak->element_klass();
2917 bool need_null_check = LayoutKindHelper::is_nullable_flat(fak->layout_kind());
2918
2919 // array reference to its class
2920 oop mirror = fak->java_mirror();
2921 if (!CallbackInvoker::report_class_reference(o, mirror)) {
2922 return false;
2923 }
2924
2925 // iterate over the array and report each reference to a
2926 // non-null element
2927 for (int index = 0; index < array->length(); index++) {
2928 address addr = (address)array->value_at_addr(index, fak->layout_helper());
2929
2930 // check for null
2931 if (need_null_check) {
2932 if (vk->is_payload_marked_as_null(addr)) {
2933 continue;
2934 }
2935 }
2936
2937 // offset in the array oop
2938 int offset = (int)(addr - cast_from_oop<address>(array));
2939 JvmtiHeapwalkObject elem(o.obj(), offset, vk, fak->layout_kind());
2940
2941 // report the array reference
2942 if (!CallbackInvoker::report_array_element_reference(o, elem, index)) {
2943 return false;
2944 }
2945 }
2946 return true;
2947 }
2948
2949 // a type array references its class
2950 inline bool VM_HeapWalkOperation::iterate_over_type_array(const JvmtiHeapwalkObject& o) {
2951 assert(!o.is_flat(), "Array object cannot be flattened");
2952 Klass* k = o.klass();
2953 oop mirror = k->java_mirror();
2954 if (!CallbackInvoker::report_class_reference(o, mirror)) {
2955 return false;
2956 }
2957
2958 // report the array contents if required
2959 if (is_reporting_primitive_array_values()) {
2960 if (!CallbackInvoker::report_primitive_array_values(o)) {
2961 return false;
2962 }
2963 }
2964 return true;
2965 }
2966
2967 #ifdef ASSERT
2968 // verify that a static oop field is in range
2969 static inline bool verify_static_oop(InstanceKlass* ik,
2970 oop mirror, int offset) {
2971 address obj_p = cast_from_oop<address>(mirror) + offset;
2972 address start = (address)InstanceMirrorKlass::start_of_static_fields(mirror);
2973 address end = start + (java_lang_Class::static_oop_field_count(mirror) * heapOopSize);
2974 assert(end >= start, "sanity check");
2975
2976 if (obj_p >= start && obj_p < end) {
2977 return true;
2978 } else {
2979 return false;
2980 }
2981 }
2982 #endif // #ifdef ASSERT
2983
2984 // a class references its super class, interfaces, class loader, ...
2985 // and finally its static fields
2986 inline bool VM_HeapWalkOperation::iterate_over_class(const JvmtiHeapwalkObject& o) {
2987 assert(!o.is_flat(), "Klass object cannot be flattened");
2988 Klass* klass = java_lang_Class::as_Klass(o.obj());
2989 int i;
2990
2991 if (klass->is_instance_klass()) {
2992 InstanceKlass* ik = InstanceKlass::cast(klass);
2993
2994 // Ignore the class if it hasn't been initialized yet
2995 if (!ik->is_linked()) {
2996 return true;
2997 }
2998
2999 // get the java mirror
3000 oop mirror_oop = klass->java_mirror();
3001 JvmtiHeapwalkObject mirror(mirror_oop);
3002
3003 // super (only if something more interesting than java.lang.Object)
3004 InstanceKlass* super_klass = ik->super();
3005 if (super_klass != nullptr && super_klass != vmClasses::Object_klass()) {
3006 oop super_oop = super_klass->java_mirror();
3007 if (!CallbackInvoker::report_superclass_reference(mirror, super_oop)) {
3008 return false;
3009 }
3010 }
3011
3012 // class loader
3013 oop cl = ik->class_loader();
3014 if (cl != nullptr) {
3015 if (!CallbackInvoker::report_class_loader_reference(mirror, cl)) {
3016 return false;
3017 }
3018 }
3019
3020 // protection domain
3021 oop pd = ik->protection_domain();
3022 if (pd != nullptr) {
3023 if (!CallbackInvoker::report_protection_domain_reference(mirror, pd)) {
3024 return false;
3025 }
3026 }
3027
3028 // signers
3029 oop signers = ik->signers();
3030 if (signers != nullptr) {
3031 if (!CallbackInvoker::report_signers_reference(mirror, signers)) {
3032 return false;
3033 }
3034 }
3035
3036 // references from the constant pool
3037 {
3038 ConstantPool* pool = ik->constants();
3039 for (int i = 1; i < pool->length(); i++) {
3040 constantTag tag = pool->tag_at(i).value();
3041 if (tag.is_string() || tag.is_klass() || tag.is_unresolved_klass()) {
3042 oop entry;
3043 if (tag.is_string()) {
3044 entry = pool->resolved_string_at(i);
3045 // If the entry is non-null it is resolved.
3046 if (entry == nullptr) {
3047 continue;
3048 }
3049 } else if (tag.is_klass()) {
3050 entry = pool->resolved_klass_at(i)->java_mirror();
3051 } else {
3052 // Code generated by JIT compilers might not resolve constant
3053 // pool entries. Treat them as resolved if they are loaded.
3054 assert(tag.is_unresolved_klass(), "must be");
3055 constantPoolHandle cp(Thread::current(), pool);
3056 Klass* klass = ConstantPool::klass_at_if_loaded(cp, i);
3057 if (klass == nullptr) {
3058 continue;
3059 }
3060 entry = klass->java_mirror();
3061 }
3062 if (!CallbackInvoker::report_constant_pool_reference(mirror, entry, (jint)i)) {
3063 return false;
3064 }
3065 }
3066 }
3067 }
3068
3069 // interfaces
3070 // (These will already have been reported as references from the constant pool
3071 // but are specified by IterateOverReachableObjects and must be reported).
3072 Array<InstanceKlass*>* interfaces = ik->local_interfaces();
3073 for (i = 0; i < interfaces->length(); i++) {
3074 oop interf = interfaces->at(i)->java_mirror();
3075 if (interf == nullptr) {
3076 continue;
3077 }
3078 if (!CallbackInvoker::report_interface_reference(mirror, interf)) {
3079 return false;
3080 }
3081 }
3082
3083 // iterate over the static fields
3084
3085 ClassFieldMap* field_map = ClassFieldMap::create_map_of_static_fields(klass);
3086 for (i=0; i<field_map->field_count(); i++) {
3087 ClassFieldDescriptor* field = field_map->field_at(i);
3088 char type = field->field_type();
3089 if (!is_primitive_field_type(type)) {
3090 oop fld_o = mirror_oop->obj_field(field->field_offset());
3091 assert(verify_static_oop(ik, mirror_oop, field->field_offset()), "sanity check");
3092 if (fld_o != nullptr) {
3093 int slot = field->field_index();
3094 if (!CallbackInvoker::report_static_field_reference(mirror, fld_o, slot)) {
3095 delete field_map;
3096 return false;
3097 }
3098 }
3099 } else {
3100 if (is_reporting_primitive_fields()) {
3101 address addr = cast_from_oop<address>(mirror_oop) + field->field_offset();
3102 int slot = field->field_index();
3103 if (!CallbackInvoker::report_primitive_static_field(mirror, slot, addr, type)) {
3104 delete field_map;
3105 return false;
3106 }
3107 }
3108 }
3109 }
3110 delete field_map;
3111
3112 return true;
3113 }
3114
3115 return true;
3116 }
3117
3118 // an object references a class and its instance fields
3119 // (static fields are ignored here as we report these as
3120 // references from the class).
3121 inline bool VM_HeapWalkOperation::iterate_over_object(const JvmtiHeapwalkObject& o) {
3122 // reference to the class
3123 if (!CallbackInvoker::report_class_reference(o, o.klass()->java_mirror())) {
3124 return false;
3125 }
3126
3127 // iterate over instance fields
3128 ClassFieldMap* field_map = JvmtiCachedClassFieldMap::get_map_of_instance_fields(o.klass());
3129 for (int i=0; i<field_map->field_count(); i++) {
3130 ClassFieldDescriptor* field = field_map->field_at(i);
3131 char type = field->field_type();
3132 int slot = field->field_index();
3133 int field_offset = field->field_offset();
3134 if (o.is_flat()) {
3135 // the object is inlined, its fields are stored without the header
3136 field_offset += o.offset() - o.inline_klass()->payload_offset();
3137 }
3138 if (!is_primitive_field_type(type)) {
3139 if (field->is_flat()) {
3140 // check for possible nulls
3141 if (LayoutKindHelper::is_nullable_flat(field->layout_kind())) {
3142 address payload = cast_from_oop<address>(o.obj()) + field_offset;
3143 if (field->inline_klass()->is_payload_marked_as_null(payload)) {
3144 continue;
3145 }
3146 }
3147 JvmtiHeapwalkObject field_obj(o.obj(), field_offset, field->inline_klass(), field->layout_kind());
3148 if (!CallbackInvoker::report_field_reference(o, field_obj, slot)) {
3149 return false;
3150 }
3151 } else {
3152 oop fld_o = o.obj()->obj_field_access<AS_NO_KEEPALIVE | ON_UNKNOWN_OOP_REF>(field_offset);
3153 // ignore any objects that aren't visible to profiler
3154 if (fld_o != nullptr) {
3155 assert(Universe::heap()->is_in(fld_o), "unsafe code should not have references to Klass* anymore");
3156 if (!CallbackInvoker::report_field_reference(o, fld_o, slot)) {
3157 return false;
3158 }
3159 }
3160 }
3161 } else {
3162 if (is_reporting_primitive_fields()) {
3163 // primitive instance field
3164 address addr = cast_from_oop<address>(o.obj()) + field_offset;
3165 if (!CallbackInvoker::report_primitive_instance_field(o, slot, addr, type)) {
3166 return false;
3167 }
3168 }
3169 }
3170 }
3171
3172 // if the object is a java.lang.String
3173 if (is_reporting_string_values() &&
3174 o.klass() == vmClasses::String_klass()) {
3175 if (!CallbackInvoker::report_string_value(o)) {
3176 return false;
3177 }
3178 }
3179 return true;
3180 }
3181
3182
3183 // Collects all simple (non-stack) roots except for threads;
3184 // threads are handled in collect_stack_roots() as an optimization.
3185 // if there's a heap root callback provided then the callback is
3186 // invoked for each simple root.
3187 // if an object reference callback is provided then all simple
3188 // roots are pushed onto the marking stack so that they can be
3189 // processed later
3190 //
3191 inline bool VM_HeapWalkOperation::collect_simple_roots() {
3192 SimpleRootsClosure blk;
3193
3194 // JNI globals
3195 blk.set_kind(JVMTI_HEAP_REFERENCE_JNI_GLOBAL);
3196 JNIHandles::oops_do(&blk);
3197 if (blk.stopped()) {
3198 return false;
3199 }
3200
3201 // Preloaded classes and loader from the system dictionary
3202 CLDRootsClosure cld_roots_closure;
3203 CLDToOopClosure cld_closure(&cld_roots_closure, ClassLoaderData::_claim_none);
3204 ClassLoaderDataGraph::always_strong_cld_do(&cld_closure);
3205 if (cld_roots_closure.stopped()) {
3206 return false;
3207 }
3208
3209 // threads are now handled in collect_stack_roots()
3210
3211 // Other kinds of roots maintained by HotSpot
3212 // Many of these won't be visible but others (such as instances of important
3213 // exceptions) will be visible.
3214 blk.set_kind(JVMTI_HEAP_REFERENCE_OTHER);
3215 Universe::vm_global()->oops_do(&blk);
3216 if (blk.stopped()) {
3217 return false;
3218 }
3219
3220 return true;
3221 }
3222
3223 // Reports the thread as JVMTI_HEAP_REFERENCE_THREAD,
3224 // walks the stack of the thread, finds all references (locals
3225 // and JNI calls) and reports these as stack references.
3226 inline bool VM_HeapWalkOperation::collect_stack_refs(JavaThread* java_thread,
3227 JNILocalRootsClosure* blk)
3228 {
3229 oop threadObj = java_thread->threadObj();
3230 oop mounted_vt = java_thread->is_vthread_mounted() ? java_thread->vthread() : nullptr;
3231 if (mounted_vt != nullptr && !JvmtiEnvBase::is_vthread_alive(mounted_vt)) {
3232 mounted_vt = nullptr;
3233 }
3234 assert(threadObj != nullptr, "sanity check");
3235
3236 StackRefCollector stack_collector(tag_map(), blk, java_thread);
3237
3238 if (!java_thread->has_last_Java_frame()) {
3239 if (!stack_collector.set_thread(JVMTI_HEAP_REFERENCE_THREAD, threadObj)) {
3240 return false;
3241 }
3242 // no last java frame but there may be JNI locals
3243 blk->set_context(_tag_map->find(threadObj), java_lang_Thread::thread_id(threadObj), 0, (jmethodID)nullptr);
3244 java_thread->active_handles()->oops_do(blk);
3245 return !blk->stopped();
3246 }
3247 // vframes are resource allocated
3248 Thread* current_thread = Thread::current();
3249 ResourceMark rm(current_thread);
3250 HandleMark hm(current_thread);
3251
3252 RegisterMap reg_map(java_thread,
3253 RegisterMap::UpdateMap::include,
3254 RegisterMap::ProcessFrames::include,
3255 RegisterMap::WalkContinuation::include);
3256
3257 // first handle mounted vthread (if any)
3258 if (mounted_vt != nullptr) {
3259 frame f = java_thread->last_frame();
3260 vframe* vf = vframe::new_vframe(&f, ®_map, java_thread);
3261 // report virtual thread as JVMTI_HEAP_REFERENCE_OTHER
3262 if (!stack_collector.set_thread(JVMTI_HEAP_REFERENCE_OTHER, mounted_vt)) {
3263 return false;
3264 }
3265 // split virtual thread and carrier thread stacks by vthread entry ("enterSpecial") frame,
3266 // consider vthread entry frame as the last vthread stack frame
3267 while (vf != nullptr) {
3268 if (!stack_collector.do_frame(vf)) {
3269 return false;
3270 }
3271 if (vf->is_vthread_entry()) {
3272 break;
3273 }
3274 vf = vf->sender();
3275 }
3276 }
3277 // Platform or carrier thread.
3278 vframe* vf = JvmtiEnvBase::get_cthread_last_java_vframe(java_thread, ®_map);
3279 if (!stack_collector.set_thread(JVMTI_HEAP_REFERENCE_THREAD, threadObj)) {
3280 return false;
3281 }
3282 return stack_collector.process_frames(vf);
3283 }
3284
3285
3286 // Collects the simple roots for all threads and collects all
3287 // stack roots - for each thread it walks the execution
3288 // stack to find all references and local JNI refs.
3289 inline bool VM_HeapWalkOperation::collect_stack_roots() {
3290 JNILocalRootsClosure blk;
3291 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) {
3292 oop threadObj = thread->threadObj();
3293 if (threadObj != nullptr && !thread->is_exiting() && !thread->is_hidden_from_external_view()) {
3294 if (!collect_stack_refs(thread, &blk)) {
3295 return false;
3296 }
3297 }
3298 }
3299 return true;
3300 }
3301
3302 // Reports stack references for the unmounted virtual thread.
3303 inline bool VM_HeapWalkOperation::collect_vthread_stack_refs(oop vt) {
3304 if (!JvmtiEnvBase::is_vthread_alive(vt)) {
3305 return true;
3306 }
3307 ContinuationWrapper cont(java_lang_VirtualThread::continuation(vt));
3308 if (cont.is_empty()) {
3309 return true;
3310 }
3311 assert(!cont.is_mounted(), "sanity check");
3312
3313 stackChunkOop chunk = cont.last_nonempty_chunk();
3314 if (chunk == nullptr || chunk->is_empty()) {
3315 return true;
3316 }
3317
3318 // vframes are resource allocated
3319 Thread* current_thread = Thread::current();
3320 ResourceMark rm(current_thread);
3321 HandleMark hm(current_thread);
3322
3323 RegisterMap reg_map(cont.continuation(), RegisterMap::UpdateMap::include);
3324
3325 JNILocalRootsClosure blk;
3326 // JavaThread is not required for unmounted virtual threads
3327 StackRefCollector stack_collector(tag_map(), &blk, nullptr);
3328 // reference to the vthread is already reported
3329 if (!stack_collector.set_thread(vt)) {
3330 return false;
3331 }
3332
3333 frame fr = chunk->top_frame(®_map);
3334 vframe* vf = vframe::new_vframe(&fr, ®_map, nullptr);
3335 return stack_collector.process_frames(vf);
3336 }
3337
3338 // visit an object
3339 // first mark the object as visited
3340 // second get all the outbound references from this object (in other words, all
3341 // the objects referenced by this object).
3342 //
3343 bool VM_HeapWalkOperation::visit(const JvmtiHeapwalkObject& o) {
3344 // mark object as visited
3345 assert(!visit_stack()->is_visited(o), "can't visit same object more than once");
3346 visit_stack()->mark_visited(o);
3347
3348 Klass* klass = o.klass();
3349 // instance
3350 if (klass->is_instance_klass()) {
3351 if (klass == vmClasses::Class_klass()) {
3352 assert(!o.is_flat(), "Class object cannot be flattened");
3353 if (!java_lang_Class::is_primitive(o.obj())) {
3354 // a java.lang.Class
3355 return iterate_over_class(o);
3356 }
3357 } else {
3358 // we report stack references only when initial object is not specified
3359 // (in the case we start from heap roots which include platform thread stack references)
3360 if (initial_object().is_null() && java_lang_VirtualThread::is_subclass(klass)) {
3361 assert(!o.is_flat(), "VirtualThread object cannot be flattened");
3362 if (!collect_vthread_stack_refs(o.obj())) {
3363 return false;
3364 }
3365 }
3366 return iterate_over_object(o);
3367 }
3368 }
3369
3370 // flat object array
3371 if (klass->is_flatArray_klass()) {
3372 return iterate_over_flat_array(o);
3373 }
3374
3375 // object array
3376 if (klass->is_objArray_klass()) {
3377 return iterate_over_array(o);
3378 }
3379
3380 // type array
3381 if (klass->is_typeArray_klass()) {
3382 return iterate_over_type_array(o);
3383 }
3384
3385 return true;
3386 }
3387
3388 void VM_HeapWalkOperation::doit() {
3389 ResourceMark rm;
3390 ClassFieldMapCacheMark cm;
3391
3392 JvmtiTagMap::check_hashmaps_for_heapwalk(_dead_objects);
3393
3394 assert(visit_stack()->is_empty(), "visit stack must be empty");
3395
3396 // the heap walk starts with an initial object or the heap roots
3397 if (initial_object().is_null()) {
3398 // can result in a big performance boost for an agent that is
3399 // focused on analyzing references in the thread stacks.
3400 if (!collect_stack_roots()) return;
3401
3402 if (!collect_simple_roots()) return;
3403 } else {
3404 visit_stack()->push(initial_object()());
3405 }
3406
3407 // object references required
3408 if (is_following_references()) {
3409
3410 // visit each object until all reachable objects have been
3411 // visited or the callback asked to terminate the iteration.
3412 while (!visit_stack()->is_empty()) {
3413 const JvmtiHeapwalkObject o = visit_stack()->pop();
3414 if (!visit_stack()->is_visited(o)) {
3415 if (!visit(o)) {
3416 break;
3417 }
3418 }
3419 }
3420 }
3421 }
3422
3423 // iterate over all objects that are reachable from a set of roots
3424 void JvmtiTagMap::iterate_over_reachable_objects(jvmtiHeapRootCallback heap_root_callback,
3425 jvmtiStackReferenceCallback stack_ref_callback,
3426 jvmtiObjectReferenceCallback object_ref_callback,
3427 const void* user_data) {
3428 // VTMS transitions must be disabled before the EscapeBarrier.
3429 MountUnmountDisabler disabler;
3430
3431 JavaThread* jt = JavaThread::current();
3432 EscapeBarrier eb(true, jt);
3433 eb.deoptimize_objects_all_threads();
3434 Arena dead_object_arena(mtServiceability);
3435 GrowableArray<jlong> dead_objects(&dead_object_arena, 10, 0, 0);
3436
3437 {
3438 MutexLocker ml(Heap_lock);
3439 BasicHeapWalkContext context(heap_root_callback, stack_ref_callback, object_ref_callback);
3440 VM_HeapWalkOperation op(this, Handle(), context, user_data, &dead_objects);
3441 VMThread::execute(&op);
3442 }
3443 convert_flat_object_entries();
3444
3445 // Post events outside of Heap_lock
3446 post_dead_objects(&dead_objects);
3447 }
3448
3449 // iterate over all objects that are reachable from a given object
3450 void JvmtiTagMap::iterate_over_objects_reachable_from_object(jobject object,
3451 jvmtiObjectReferenceCallback object_ref_callback,
3452 const void* user_data) {
3453 oop obj = JNIHandles::resolve(object);
3454 Handle initial_object(Thread::current(), obj);
3455
3456 Arena dead_object_arena(mtServiceability);
3457 GrowableArray<jlong> dead_objects(&dead_object_arena, 10, 0, 0);
3458
3459 MountUnmountDisabler disabler;
3460
3461 {
3462 MutexLocker ml(Heap_lock);
3463 BasicHeapWalkContext context(nullptr, nullptr, object_ref_callback);
3464 VM_HeapWalkOperation op(this, initial_object, context, user_data, &dead_objects);
3465 VMThread::execute(&op);
3466 }
3467 convert_flat_object_entries();
3468
3469 // Post events outside of Heap_lock
3470 post_dead_objects(&dead_objects);
3471 }
3472
3473 // follow references from an initial object or the GC roots
3474 void JvmtiTagMap::follow_references(jint heap_filter,
3475 Klass* klass,
3476 jobject object,
3477 const jvmtiHeapCallbacks* callbacks,
3478 const void* user_data)
3479 {
3480 // VTMS transitions must be disabled before the EscapeBarrier.
3481 MountUnmountDisabler disabler;
3482
3483 oop obj = JNIHandles::resolve(object);
3484 JavaThread* jt = JavaThread::current();
3485 Handle initial_object(jt, obj);
3486 // EA based optimizations that are tagged or reachable from initial_object are already reverted.
3487 EscapeBarrier eb(initial_object.is_null() &&
3488 !(heap_filter & JVMTI_HEAP_FILTER_UNTAGGED),
3489 jt);
3490 eb.deoptimize_objects_all_threads();
3491
3492 Arena dead_object_arena(mtServiceability);
3493 GrowableArray<jlong> dead_objects(&dead_object_arena, 10, 0, 0);
3494
3495 {
3496 MutexLocker ml(Heap_lock);
3497 AdvancedHeapWalkContext context(heap_filter, klass, callbacks);
3498 VM_HeapWalkOperation op(this, initial_object, context, user_data, &dead_objects);
3499 VMThread::execute(&op);
3500 }
3501 convert_flat_object_entries();
3502
3503 // Post events outside of Heap_lock
3504 post_dead_objects(&dead_objects);
3505 }
3506
3507 // Verify gc_notification follows set_needs_cleaning.
3508 DEBUG_ONLY(static bool notified_needs_cleaning = false;)
3509
3510 void JvmtiTagMap::set_needs_cleaning() {
3511 assert(SafepointSynchronize::is_at_safepoint(), "called in gc pause");
3512 assert(Thread::current()->is_VM_thread(), "should be the VM thread");
3513 // Can't assert !notified_needs_cleaning; a partial GC might be upgraded
3514 // to a full GC and do this twice without intervening gc_notification.
3515 DEBUG_ONLY(notified_needs_cleaning = true;)
3516
3517 JvmtiEnvIterator it;
3518 for (JvmtiEnv* env = it.first(); env != nullptr; env = it.next(env)) {
3519 JvmtiTagMap* tag_map = env->tag_map_acquire();
3520 if (tag_map != nullptr) {
3521 tag_map->_needs_cleaning = !tag_map->is_empty();
3522 }
3523 }
3524 }
3525
3526 void JvmtiTagMap::gc_notification(size_t num_dead_entries) {
3527 assert(notified_needs_cleaning, "missing GC notification");
3528 DEBUG_ONLY(notified_needs_cleaning = false;)
3529
3530 // Notify ServiceThread if there's work to do.
3531 {
3532 MonitorLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
3533 _has_object_free_events = (num_dead_entries != 0);
3534 if (_has_object_free_events) ml.notify_all();
3535 }
3536
3537 // If no dead entries then cancel cleaning requests.
3538 if (num_dead_entries == 0) {
3539 JvmtiEnvIterator it;
3540 for (JvmtiEnv* env = it.first(); env != nullptr; env = it.next(env)) {
3541 JvmtiTagMap* tag_map = env->tag_map_acquire();
3542 if (tag_map != nullptr) {
3543 MutexLocker ml (tag_map->lock(), Mutex::_no_safepoint_check_flag);
3544 tag_map->_needs_cleaning = false;
3545 }
3546 }
3547 }
3548 }
3549
3550 // Used by ServiceThread to discover there is work to do.
3551 bool JvmtiTagMap::has_object_free_events_and_reset() {
3552 assert_lock_strong(Service_lock);
3553 bool result = _has_object_free_events;
3554 _has_object_free_events = false;
3555 return result;
3556 }
3557
3558 // Used by ServiceThread to clean up tagmaps.
3559 void JvmtiTagMap::flush_all_object_free_events() {
3560 JavaThread* thread = JavaThread::current();
3561 JvmtiEnvIterator it;
3562 for (JvmtiEnv* env = it.first(); env != nullptr; env = it.next(env)) {
3563 JvmtiTagMap* tag_map = env->tag_map_acquire();
3564 if (tag_map != nullptr) {
3565 tag_map->flush_object_free_events();
3566 ThreadBlockInVM tbiv(thread); // Be safepoint-polite while looping.
3567 }
3568 }
3569 }