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