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/mountUnmountDisabler.hpp"
61 #include "runtime/mutex.hpp"
62 #include "runtime/mutexLocker.hpp"
63 #include "runtime/safepoint.hpp"
64 #include "runtime/threadSMR.hpp"
65 #include "runtime/timerTrace.hpp"
66 #include "runtime/vframe.hpp"
67 #include "runtime/vmOperations.hpp"
68 #include "runtime/vmThread.hpp"
69 #include "utilities/macros.hpp"
70 #include "utilities/objectBitSet.inline.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 count += interfaces->at(i)->java_fields_count();
434
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->super(); super_klass != nullptr; super_klass = super_klass->super()) {
456 index += super_klass->java_fields_count();
457 }
458
459 for (JavaFieldStream fld(ik); !fld.done(); fld.next(), index++) {
460 // ignore instance fields
461 if (!fld.access_flags().is_static()) {
462 continue;
463 }
464 field_map->add(index, fld.signature()->char_at(0), fld.offset());
465 }
466
467 return field_map;
468 }
469
470 // Returns a heap allocated ClassFieldMap to describe the instance fields
471 // of the given class. All instance fields are included (this means public
472 // and private fields declared in superclasses too).
473 ClassFieldMap* ClassFieldMap::create_map_of_instance_fields(oop obj) {
474 InstanceKlass* ik = InstanceKlass::cast(obj->klass());
475
476 // create the field map
477 ClassFieldMap* field_map = new ClassFieldMap();
478
479 // fields of the superclasses are reported first, so need to know total field number to calculate field indices
480 int total_field_number = interfaces_field_count(ik);
481 for (InstanceKlass* klass = ik; klass != nullptr; klass = klass->super()) {
482 total_field_number += klass->java_fields_count();
483 }
484
485 for (InstanceKlass* klass = ik; klass != nullptr; klass = klass->super()) {
486 JavaFieldStream fld(klass);
487 int start_index = total_field_number - klass->java_fields_count();
488 for (int index = 0; !fld.done(); fld.next(), index++) {
489 // ignore static fields
490 if (fld.access_flags().is_static()) {
491 continue;
492 }
493 field_map->add(start_index + index, fld.signature()->char_at(0), fld.offset());
494 }
495 // update total_field_number for superclass (decrease by the field count in the current class)
496 total_field_number = start_index;
497 }
498
499 return field_map;
500 }
501
502 // Helper class used to cache a ClassFileMap for the instance fields of
503 // a cache. A JvmtiCachedClassFieldMap can be cached by an InstanceKlass during
504 // heap iteration and avoid creating a field map for each object in the heap
505 // (only need to create the map when the first instance of a class is encountered).
506 //
507 class JvmtiCachedClassFieldMap : public CHeapObj<mtInternal> {
508 private:
509 enum {
510 initial_class_count = 200
511 };
512 ClassFieldMap* _field_map;
513
514 ClassFieldMap* field_map() const { return _field_map; }
515
516 JvmtiCachedClassFieldMap(ClassFieldMap* field_map);
517 ~JvmtiCachedClassFieldMap();
518
519 static GrowableArray<InstanceKlass*>* _class_list;
520 static void add_to_class_list(InstanceKlass* ik);
521
522 public:
523 // returns the field map for a given object (returning map cached
524 // by InstanceKlass if possible
525 static ClassFieldMap* get_map_of_instance_fields(oop obj);
526
527 // removes the field map from all instanceKlasses - should be
528 // called before VM operation completes
529 static void clear_cache();
530
531 // returns the number of ClassFieldMap cached by instanceKlasses
532 static int cached_field_map_count();
533 };
534
535 GrowableArray<InstanceKlass*>* JvmtiCachedClassFieldMap::_class_list;
536
537 JvmtiCachedClassFieldMap::JvmtiCachedClassFieldMap(ClassFieldMap* field_map) {
538 _field_map = field_map;
539 }
540
541 JvmtiCachedClassFieldMap::~JvmtiCachedClassFieldMap() {
542 if (_field_map != nullptr) {
543 delete _field_map;
544 }
545 }
557 _is_active = true;
558 }
559 ~ClassFieldMapCacheMark() {
560 JvmtiCachedClassFieldMap::clear_cache();
561 _is_active = false;
562 }
563 static bool is_active() { return _is_active; }
564 };
565
566 bool ClassFieldMapCacheMark::_is_active;
567
568 // record that the given InstanceKlass is caching a field map
569 void JvmtiCachedClassFieldMap::add_to_class_list(InstanceKlass* ik) {
570 if (_class_list == nullptr) {
571 _class_list = new (mtServiceability)
572 GrowableArray<InstanceKlass*>(initial_class_count, mtServiceability);
573 }
574 _class_list->push(ik);
575 }
576
577 // returns the instance field map for the given object
578 // (returns field map cached by the InstanceKlass if possible)
579 ClassFieldMap* JvmtiCachedClassFieldMap::get_map_of_instance_fields(oop obj) {
580 assert(Thread::current()->is_VM_thread(), "must be VMThread");
581 assert(ClassFieldMapCacheMark::is_active(), "ClassFieldMapCacheMark not active");
582
583 Klass* k = obj->klass();
584 InstanceKlass* ik = InstanceKlass::cast(k);
585
586 // return cached map if possible
587 JvmtiCachedClassFieldMap* cached_map = ik->jvmti_cached_class_field_map();
588 if (cached_map != nullptr) {
589 assert(cached_map->field_map() != nullptr, "missing field list");
590 return cached_map->field_map();
591 } else {
592 ClassFieldMap* field_map = ClassFieldMap::create_map_of_instance_fields(obj);
593 cached_map = new JvmtiCachedClassFieldMap(field_map);
594 ik->set_jvmti_cached_class_field_map(cached_map);
595 add_to_class_list(ik);
596 return field_map;
597 }
598 }
599
600 // remove the fields maps cached from all instanceKlasses
601 void JvmtiCachedClassFieldMap::clear_cache() {
602 assert(Thread::current()->is_VM_thread(), "must be VMThread");
603 if (_class_list != nullptr) {
604 for (int i = 0; i < _class_list->length(); i++) {
605 InstanceKlass* ik = _class_list->at(i);
606 JvmtiCachedClassFieldMap* cached_map = ik->jvmti_cached_class_field_map();
607 assert(cached_map != nullptr, "should not be null");
608 ik->set_jvmti_cached_class_field_map(nullptr);
609 delete cached_map; // deletes the encapsulated field map
610 }
611 delete _class_list;
612 _class_list = nullptr;
624 int heap_filter) {
625 // apply the heap filter
626 if (obj_tag != 0) {
627 // filter out tagged objects
628 if (heap_filter & JVMTI_HEAP_FILTER_TAGGED) return true;
629 } else {
630 // filter out untagged objects
631 if (heap_filter & JVMTI_HEAP_FILTER_UNTAGGED) return true;
632 }
633 if (klass_tag != 0) {
634 // filter out objects with tagged classes
635 if (heap_filter & JVMTI_HEAP_FILTER_CLASS_TAGGED) return true;
636 } else {
637 // filter out objects with untagged classes.
638 if (heap_filter & JVMTI_HEAP_FILTER_CLASS_UNTAGGED) return true;
639 }
640 return false;
641 }
642
643 // helper function to indicate if an object is filtered by a klass filter
644 static inline bool is_filtered_by_klass_filter(oop obj, Klass* klass_filter) {
645 if (klass_filter != nullptr) {
646 if (obj->klass() != klass_filter) {
647 return true;
648 }
649 }
650 return false;
651 }
652
653 // helper function to tell if a field is a primitive field or not
654 static inline bool is_primitive_field_type(char type) {
655 return (type != JVM_SIGNATURE_CLASS && type != JVM_SIGNATURE_ARRAY);
656 }
657
658 // helper function to copy the value from location addr to jvalue.
659 static inline void copy_to_jvalue(jvalue *v, address addr, jvmtiPrimitiveType value_type) {
660 switch (value_type) {
661 case JVMTI_PRIMITIVE_TYPE_BOOLEAN : { v->z = *(jboolean*)addr; break; }
662 case JVMTI_PRIMITIVE_TYPE_BYTE : { v->b = *(jbyte*)addr; break; }
663 case JVMTI_PRIMITIVE_TYPE_CHAR : { v->c = *(jchar*)addr; break; }
664 case JVMTI_PRIMITIVE_TYPE_SHORT : { v->s = *(jshort*)addr; break; }
665 case JVMTI_PRIMITIVE_TYPE_INT : { v->i = *(jint*)addr; break; }
666 case JVMTI_PRIMITIVE_TYPE_LONG : { v->j = *(jlong*)addr; break; }
667 case JVMTI_PRIMITIVE_TYPE_FLOAT : { v->f = *(jfloat*)addr; break; }
668 case JVMTI_PRIMITIVE_TYPE_DOUBLE : { v->d = *(jdouble*)addr; break; }
669 default: ShouldNotReachHere();
670 }
671 }
672
673 // helper function to invoke string primitive value callback
674 // returns visit control flags
675 static jint invoke_string_value_callback(jvmtiStringPrimitiveValueCallback cb,
676 CallbackWrapper* wrapper,
677 oop str,
678 void* user_data)
679 {
680 assert(str->klass() == vmClasses::String_klass(), "not a string");
681
682 typeArrayOop s_value = java_lang_String::value(str);
683
684 // JDK-6584008: the value field may be null if a String instance is
685 // partially constructed.
686 if (s_value == nullptr) {
687 return 0;
688 }
689 // get the string value and length
690 // (string value may be offset from the base)
691 int s_len = java_lang_String::length(str);
692 bool is_latin1 = java_lang_String::is_latin1(str);
693 jchar* value;
694 if (s_len > 0) {
695 if (!is_latin1) {
696 value = s_value->char_at_addr(0);
697 } else {
698 // Inflate latin1 encoded string to UTF16
699 jchar* buf = NEW_C_HEAP_ARRAY(jchar, s_len, mtInternal);
708 }
709
710 // invoke the callback
711 jint res = (*cb)(wrapper->klass_tag(),
712 wrapper->obj_size(),
713 wrapper->obj_tag_p(),
714 value,
715 (jint)s_len,
716 user_data);
717
718 if (is_latin1 && s_len > 0) {
719 FREE_C_HEAP_ARRAY(jchar, value);
720 }
721 return res;
722 }
723
724 // helper function to invoke string primitive value callback
725 // returns visit control flags
726 static jint invoke_array_primitive_value_callback(jvmtiArrayPrimitiveValueCallback cb,
727 CallbackWrapper* wrapper,
728 oop obj,
729 void* user_data)
730 {
731 assert(obj->is_typeArray(), "not a primitive array");
732
733 // get base address of first element
734 typeArrayOop array = typeArrayOop(obj);
735 BasicType type = TypeArrayKlass::cast(array->klass())->element_type();
736 void* elements = array->base(type);
737
738 // jvmtiPrimitiveType is defined so this mapping is always correct
739 jvmtiPrimitiveType elem_type = (jvmtiPrimitiveType)type2char(type);
740
741 return (*cb)(wrapper->klass_tag(),
742 wrapper->obj_size(),
743 wrapper->obj_tag_p(),
744 (jint)array->length(),
745 elem_type,
746 elements,
747 user_data);
748 }
749
750 // helper function to invoke the primitive field callback for all static fields
751 // of a given class
752 static jint invoke_primitive_field_callback_for_static_fields
753 (CallbackWrapper* wrapper,
754 oop obj,
804 &reference_info,
805 wrapper->klass_tag(),
806 wrapper->obj_tag_p(),
807 value,
808 value_type,
809 user_data);
810 if (res & JVMTI_VISIT_ABORT) {
811 delete field_map;
812 return res;
813 }
814 }
815
816 delete field_map;
817 return 0;
818 }
819
820 // helper function to invoke the primitive field callback for all instance fields
821 // of a given object
822 static jint invoke_primitive_field_callback_for_instance_fields(
823 CallbackWrapper* wrapper,
824 oop obj,
825 jvmtiPrimitiveFieldCallback cb,
826 void* user_data)
827 {
828 // for instance fields only the index will be set
829 static jvmtiHeapReferenceInfo reference_info = { 0 };
830
831 // get the map of the instance fields
832 ClassFieldMap* fields = JvmtiCachedClassFieldMap::get_map_of_instance_fields(obj);
833
834 // invoke the callback for each instance primitive field
835 for (int i=0; i<fields->field_count(); i++) {
836 ClassFieldDescriptor* field = fields->field_at(i);
837
838 // ignore non-primitive fields
839 char type = field->field_type();
840 if (!is_primitive_field_type(type)) {
841 continue;
842 }
843 // one-to-one mapping
844 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
845
846 // get offset and field value
847 int offset = field->field_offset();
848 address addr = cast_from_oop<address>(obj) + offset;
849 jvalue value;
850 copy_to_jvalue(&value, addr, value_type);
851
852 // field index
853 reference_info.field.index = field->field_index();
854
855 // invoke the callback
856 jint res = (*cb)(JVMTI_HEAP_REFERENCE_FIELD,
857 &reference_info,
858 wrapper->klass_tag(),
859 wrapper->obj_tag_p(),
860 value,
861 value_type,
862 user_data);
863 if (res & JVMTI_VISIT_ABORT) {
864 return res;
865 }
866 }
867 return 0;
868 }
942
943 // invoked for each object in the heap
944 void IterateOverHeapObjectClosure::do_object(oop o) {
945 assert(o != nullptr, "Heap iteration should never produce null!");
946 // check if iteration has been halted
947 if (is_iteration_aborted()) return;
948
949 // instanceof check when filtering by klass
950 if (klass() != nullptr && !o->is_a(klass())) {
951 return;
952 }
953
954 // skip if object is a dormant shared object whose mirror hasn't been loaded
955 if (o->klass()->java_mirror() == nullptr) {
956 log_debug(aot, heap)("skipped dormant archived object " INTPTR_FORMAT " (%s)", p2i(o),
957 o->klass()->external_name());
958 return;
959 }
960
961 // prepare for the calllback
962 CallbackWrapper wrapper(tag_map(), o);
963
964 // if the object is tagged and we're only interested in untagged objects
965 // then don't invoke the callback. Similarly, if the object is untagged
966 // and we're only interested in tagged objects we skip the callback.
967 if (wrapper.obj_tag() != 0) {
968 if (object_filter() == JVMTI_HEAP_OBJECT_UNTAGGED) return;
969 } else {
970 if (object_filter() == JVMTI_HEAP_OBJECT_TAGGED) return;
971 }
972
973 // invoke the agent's callback
974 jvmtiIterationControl control = (*object_callback())(wrapper.klass_tag(),
975 wrapper.obj_size(),
976 wrapper.obj_tag_p(),
977 (void*)user_data());
978 if (control == JVMTI_ITERATION_ABORT) {
979 set_iteration_aborted(true);
980 }
981 }
982
994 int heap_filter() const { return _heap_filter; }
995 const jvmtiHeapCallbacks* callbacks() const { return _callbacks; }
996 Klass* klass() const { return _klass; }
997 const void* user_data() const { return _user_data; }
998
999 // indicates if the iteration has been aborted
1000 bool _iteration_aborted;
1001 bool is_iteration_aborted() const { return _iteration_aborted; }
1002
1003 // used to check the visit control flags. If the abort flag is set
1004 // then we set the iteration aborted flag so that the iteration completes
1005 // without processing any further objects
1006 bool check_flags_for_abort(jint flags) {
1007 bool is_abort = (flags & JVMTI_VISIT_ABORT) != 0;
1008 if (is_abort) {
1009 _iteration_aborted = true;
1010 }
1011 return is_abort;
1012 }
1013
1014 public:
1015 IterateThroughHeapObjectClosure(JvmtiTagMap* tag_map,
1016 Klass* klass,
1017 int heap_filter,
1018 const jvmtiHeapCallbacks* heap_callbacks,
1019 const void* user_data) :
1020 _tag_map(tag_map),
1021 _klass(klass),
1022 _heap_filter(heap_filter),
1023 _callbacks(heap_callbacks),
1024 _user_data(user_data),
1025 _iteration_aborted(false)
1026 {
1027 }
1028
1029 void do_object(oop o);
1030 };
1031
1032 // invoked for each object in the heap
1033 void IterateThroughHeapObjectClosure::do_object(oop obj) {
1034 assert(obj != nullptr, "Heap iteration should never produce null!");
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->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;
1313 if (error != JVMTI_ERROR_NONE) {
1314 if (object_result_ptr != nullptr) {
1315 _env->Deallocate((unsigned char*)object_result_ptr);
1316 }
1317 return error;
1318 }
1319 for (int i=0; i<count; i++) {
1320 (*tag_result_ptr)[i] = (jlong)_tag_results->at(i);
1321 }
1322 }
1323
1324 *count_ptr = count;
1325 return JVMTI_ERROR_NONE;
1326 }
1327 };
1328
1329 // return the list of objects with the specified tags
1330 jvmtiError JvmtiTagMap::get_objects_with_tags(const jlong* tags,
1331 jint count, jint* count_ptr, jobject** object_result_ptr, jlong** tag_result_ptr) {
1332
1333 TagObjectCollector collector(env(), tags, count);
1334 {
1335 // iterate over all tagged objects
1336 MutexLocker ml(lock(), Mutex::_no_safepoint_check_flag);
1337 // Can't post ObjectFree events here from a JavaThread, so this
1338 // will race with the gc_notification thread in the tiny
1339 // window where the object is not marked but hasn't been notified that
1340 // it is collected yet.
1341 entry_iterate(&collector);
1342 }
1343 return collector.result(count_ptr, object_result_ptr, tag_result_ptr);
1344 }
1345
1346 // helper to map a jvmtiHeapReferenceKind to an old style jvmtiHeapRootKind
1347 // (not performance critical as only used for roots)
1348 static jvmtiHeapRootKind toJvmtiHeapRootKind(jvmtiHeapReferenceKind kind) {
1349 switch (kind) {
1350 case JVMTI_HEAP_REFERENCE_JNI_GLOBAL: return JVMTI_HEAP_ROOT_JNI_GLOBAL;
1351 case JVMTI_HEAP_REFERENCE_SYSTEM_CLASS: return JVMTI_HEAP_ROOT_SYSTEM_CLASS;
1352 case JVMTI_HEAP_REFERENCE_STACK_LOCAL: return JVMTI_HEAP_ROOT_STACK_LOCAL;
1353 case JVMTI_HEAP_REFERENCE_JNI_LOCAL: return JVMTI_HEAP_ROOT_JNI_LOCAL;
1354 case JVMTI_HEAP_REFERENCE_THREAD: return JVMTI_HEAP_ROOT_THREAD;
1355 case JVMTI_HEAP_REFERENCE_OTHER: return JVMTI_HEAP_ROOT_OTHER;
1356 default: ShouldNotReachHere(); return JVMTI_HEAP_ROOT_OTHER;
1357 }
1358 }
1359
1360 // Base class for all heap walk contexts. The base class maintains a flag
1361 // to indicate if the context is valid or not.
1362 class HeapWalkContext {
1363 private:
1364 bool _valid;
1365 public:
1366 HeapWalkContext(bool valid) { _valid = valid; }
1367 void invalidate() { _valid = false; }
1368 bool is_valid() const { return _valid; }
1369 };
1370
1371 // A basic heap walk context for the deprecated heap walking functions.
1372 // The context for a basic heap walk are the callbacks and fields used by
1373 // the referrer caching scheme.
1374 class BasicHeapWalkContext: public HeapWalkContext {
1375 private:
1376 jvmtiHeapRootCallback _heap_root_callback;
1377 jvmtiStackReferenceCallback _stack_ref_callback;
1378 jvmtiObjectReferenceCallback _object_ref_callback;
1379
1380 // used for caching
1381 oop _last_referrer;
1382 jlong _last_referrer_tag;
1383
1384 public:
1385 BasicHeapWalkContext() : HeapWalkContext(false) { }
1386
1387 BasicHeapWalkContext(jvmtiHeapRootCallback heap_root_callback,
1388 jvmtiStackReferenceCallback stack_ref_callback,
1389 jvmtiObjectReferenceCallback object_ref_callback) :
1390 HeapWalkContext(true),
1391 _heap_root_callback(heap_root_callback),
1392 _stack_ref_callback(stack_ref_callback),
1393 _object_ref_callback(object_ref_callback),
1394 _last_referrer(nullptr),
1395 _last_referrer_tag(0) {
1396 }
1397
1398 // accessors
1399 jvmtiHeapRootCallback heap_root_callback() const { return _heap_root_callback; }
1400 jvmtiStackReferenceCallback stack_ref_callback() const { return _stack_ref_callback; }
1401 jvmtiObjectReferenceCallback object_ref_callback() const { return _object_ref_callback; }
1402
1403 oop last_referrer() const { return _last_referrer; }
1404 void set_last_referrer(oop referrer) { _last_referrer = referrer; }
1405 jlong last_referrer_tag() const { return _last_referrer_tag; }
1406 void set_last_referrer_tag(jlong value) { _last_referrer_tag = value; }
1407 };
1408
1409 // The advanced heap walk context for the FollowReferences functions.
1410 // The context is the callbacks, and the fields used for filtering.
1411 class AdvancedHeapWalkContext: public HeapWalkContext {
1412 private:
1413 jint _heap_filter;
1414 Klass* _klass_filter;
1415 const jvmtiHeapCallbacks* _heap_callbacks;
1416
1417 public:
1418 AdvancedHeapWalkContext() : HeapWalkContext(false) { }
1419
1420 AdvancedHeapWalkContext(jint heap_filter,
1421 Klass* klass_filter,
1422 const jvmtiHeapCallbacks* heap_callbacks) :
1423 HeapWalkContext(true),
1424 _heap_filter(heap_filter),
1457 static bool is_basic_heap_walk() { return _heap_walk_type == basic; }
1458 static bool is_advanced_heap_walk() { return _heap_walk_type == advanced; }
1459
1460 // context for basic style heap walk
1461 static BasicHeapWalkContext _basic_context;
1462 static BasicHeapWalkContext* basic_context() {
1463 assert(_basic_context.is_valid(), "invalid");
1464 return &_basic_context;
1465 }
1466
1467 // context for advanced style heap walk
1468 static AdvancedHeapWalkContext _advanced_context;
1469 static AdvancedHeapWalkContext* advanced_context() {
1470 assert(_advanced_context.is_valid(), "invalid");
1471 return &_advanced_context;
1472 }
1473
1474 // context needed for all heap walks
1475 static JvmtiTagMap* _tag_map;
1476 static const void* _user_data;
1477 static GrowableArray<oop>* _visit_stack;
1478 static JVMTIBitSet* _bitset;
1479
1480 // accessors
1481 static JvmtiTagMap* tag_map() { return _tag_map; }
1482 static const void* user_data() { return _user_data; }
1483 static GrowableArray<oop>* visit_stack() { return _visit_stack; }
1484
1485 // if the object hasn't been visited then push it onto the visit stack
1486 // so that it will be visited later
1487 static inline bool check_for_visit(oop obj) {
1488 if (!_bitset->is_marked(obj)) visit_stack()->push(obj);
1489 return true;
1490 }
1491
1492 // invoke basic style callbacks
1493 static inline bool invoke_basic_heap_root_callback
1494 (jvmtiHeapRootKind root_kind, oop obj);
1495 static inline bool invoke_basic_stack_ref_callback
1496 (jvmtiHeapRootKind root_kind, jlong thread_tag, jint depth, jmethodID method,
1497 int slot, oop obj);
1498 static inline bool invoke_basic_object_reference_callback
1499 (jvmtiObjectReferenceKind ref_kind, oop referrer, oop referree, jint index);
1500
1501 // invoke advanced style callbacks
1502 static inline bool invoke_advanced_heap_root_callback
1503 (jvmtiHeapReferenceKind ref_kind, oop obj);
1504 static inline bool invoke_advanced_stack_ref_callback
1505 (jvmtiHeapReferenceKind ref_kind, jlong thread_tag, jlong tid, int depth,
1506 jmethodID method, jlocation bci, jint slot, oop obj);
1507 static inline bool invoke_advanced_object_reference_callback
1508 (jvmtiHeapReferenceKind ref_kind, oop referrer, oop referree, jint index);
1509
1510 // used to report the value of primitive fields
1511 static inline bool report_primitive_field
1512 (jvmtiHeapReferenceKind ref_kind, oop obj, jint index, address addr, char type);
1513
1514 public:
1515 // initialize for basic mode
1516 static void initialize_for_basic_heap_walk(JvmtiTagMap* tag_map,
1517 GrowableArray<oop>* visit_stack,
1518 const void* user_data,
1519 BasicHeapWalkContext context,
1520 JVMTIBitSet* bitset);
1521
1522 // initialize for advanced mode
1523 static void initialize_for_advanced_heap_walk(JvmtiTagMap* tag_map,
1524 GrowableArray<oop>* visit_stack,
1525 const void* user_data,
1526 AdvancedHeapWalkContext context,
1527 JVMTIBitSet* bitset);
1528
1529 // functions to report roots
1530 static inline bool report_simple_root(jvmtiHeapReferenceKind kind, oop o);
1531 static inline bool report_jni_local_root(jlong thread_tag, jlong tid, jint depth,
1532 jmethodID m, oop o);
1533 static inline bool report_stack_ref_root(jlong thread_tag, jlong tid, jint depth,
1534 jmethodID method, jlocation bci, jint slot, oop o);
1535
1536 // functions to report references
1537 static inline bool report_array_element_reference(oop referrer, oop referree, jint index);
1538 static inline bool report_class_reference(oop referrer, oop referree);
1539 static inline bool report_class_loader_reference(oop referrer, oop referree);
1540 static inline bool report_signers_reference(oop referrer, oop referree);
1541 static inline bool report_protection_domain_reference(oop referrer, oop referree);
1542 static inline bool report_superclass_reference(oop referrer, oop referree);
1543 static inline bool report_interface_reference(oop referrer, oop referree);
1544 static inline bool report_static_field_reference(oop referrer, oop referree, jint slot);
1545 static inline bool report_field_reference(oop referrer, oop referree, jint slot);
1546 static inline bool report_constant_pool_reference(oop referrer, oop referree, jint index);
1547 static inline bool report_primitive_array_values(oop array);
1548 static inline bool report_string_value(oop str);
1549 static inline bool report_primitive_instance_field(oop o, jint index, address value, char type);
1550 static inline bool report_primitive_static_field(oop o, jint index, address value, char type);
1551 };
1552
1553 // statics
1554 int CallbackInvoker::_heap_walk_type;
1555 BasicHeapWalkContext CallbackInvoker::_basic_context;
1556 AdvancedHeapWalkContext CallbackInvoker::_advanced_context;
1557 JvmtiTagMap* CallbackInvoker::_tag_map;
1558 const void* CallbackInvoker::_user_data;
1559 GrowableArray<oop>* CallbackInvoker::_visit_stack;
1560 JVMTIBitSet* CallbackInvoker::_bitset;
1561
1562 // initialize for basic heap walk (IterateOverReachableObjects et al)
1563 void CallbackInvoker::initialize_for_basic_heap_walk(JvmtiTagMap* tag_map,
1564 GrowableArray<oop>* visit_stack,
1565 const void* user_data,
1566 BasicHeapWalkContext context,
1567 JVMTIBitSet* bitset) {
1568 _tag_map = tag_map;
1569 _visit_stack = visit_stack;
1570 _user_data = user_data;
1571 _basic_context = context;
1572 _advanced_context.invalidate(); // will trigger assertion if used
1573 _heap_walk_type = basic;
1574 _bitset = bitset;
1575 }
1576
1577 // initialize for advanced heap walk (FollowReferences)
1578 void CallbackInvoker::initialize_for_advanced_heap_walk(JvmtiTagMap* tag_map,
1579 GrowableArray<oop>* visit_stack,
1580 const void* user_data,
1581 AdvancedHeapWalkContext context,
1582 JVMTIBitSet* bitset) {
1583 _tag_map = tag_map;
1584 _visit_stack = visit_stack;
1585 _user_data = user_data;
1586 _advanced_context = context;
1587 _basic_context.invalidate(); // will trigger assertion if used
1588 _heap_walk_type = advanced;
1589 _bitset = bitset;
1590 }
1591
1592
1593 // invoke basic style heap root callback
1594 inline bool CallbackInvoker::invoke_basic_heap_root_callback(jvmtiHeapRootKind root_kind, oop obj) {
1595 // if we heap roots should be reported
1596 jvmtiHeapRootCallback cb = basic_context()->heap_root_callback();
1597 if (cb == nullptr) {
1598 return check_for_visit(obj);
1599 }
1600
1601 CallbackWrapper wrapper(tag_map(), obj);
1602 jvmtiIterationControl control = (*cb)(root_kind,
1603 wrapper.klass_tag(),
1604 wrapper.obj_size(),
1605 wrapper.obj_tag_p(),
1606 (void*)user_data());
1607 // push root to visit stack when following references
1608 if (control == JVMTI_ITERATION_CONTINUE &&
1609 basic_context()->object_ref_callback() != nullptr) {
1610 visit_stack()->push(obj);
1611 }
1612 return control != JVMTI_ITERATION_ABORT;
1613 }
1614
1615 // invoke basic style stack ref callback
1616 inline bool CallbackInvoker::invoke_basic_stack_ref_callback(jvmtiHeapRootKind root_kind,
1617 jlong thread_tag,
1618 jint depth,
1619 jmethodID method,
1620 int slot,
1621 oop obj) {
1622 // if we stack refs should be reported
1623 jvmtiStackReferenceCallback cb = basic_context()->stack_ref_callback();
1624 if (cb == nullptr) {
1625 return check_for_visit(obj);
1626 }
1627
1628 CallbackWrapper wrapper(tag_map(), obj);
1629 jvmtiIterationControl control = (*cb)(root_kind,
1630 wrapper.klass_tag(),
1631 wrapper.obj_size(),
1632 wrapper.obj_tag_p(),
1633 thread_tag,
1634 depth,
1635 method,
1636 slot,
1637 (void*)user_data());
1638 // push root to visit stack when following references
1639 if (control == JVMTI_ITERATION_CONTINUE &&
1640 basic_context()->object_ref_callback() != nullptr) {
1641 visit_stack()->push(obj);
1642 }
1643 return control != JVMTI_ITERATION_ABORT;
1644 }
1645
1646 // invoke basic style object reference callback
1647 inline bool CallbackInvoker::invoke_basic_object_reference_callback(jvmtiObjectReferenceKind ref_kind,
1648 oop referrer,
1649 oop referree,
1650 jint index) {
1651
1652 BasicHeapWalkContext* context = basic_context();
1653
1654 // callback requires the referrer's tag. If it's the same referrer
1655 // as the last call then we use the cached value.
1656 jlong referrer_tag;
1657 if (referrer == context->last_referrer()) {
1658 referrer_tag = context->last_referrer_tag();
1659 } else {
1660 referrer_tag = tag_for(tag_map(), referrer);
1661 }
1662
1663 // do the callback
1664 CallbackWrapper wrapper(tag_map(), referree);
1665 jvmtiObjectReferenceCallback cb = context->object_ref_callback();
1666 jvmtiIterationControl control = (*cb)(ref_kind,
1667 wrapper.klass_tag(),
1668 wrapper.obj_size(),
1669 wrapper.obj_tag_p(),
1670 referrer_tag,
1671 index,
1672 (void*)user_data());
1673
1674 // record referrer and referrer tag. For self-references record the
1675 // tag value from the callback as this might differ from referrer_tag.
1676 context->set_last_referrer(referrer);
1677 if (referrer == referree) {
1678 context->set_last_referrer_tag(*wrapper.obj_tag_p());
1679 } else {
1680 context->set_last_referrer_tag(referrer_tag);
1681 }
1682
1683 if (control == JVMTI_ITERATION_CONTINUE) {
1684 return check_for_visit(referree);
1685 } else {
1686 return control != JVMTI_ITERATION_ABORT;
1687 }
1688 }
1689
1690 // invoke advanced style heap root callback
1691 inline bool CallbackInvoker::invoke_advanced_heap_root_callback(jvmtiHeapReferenceKind ref_kind,
1692 oop obj) {
1693 AdvancedHeapWalkContext* context = advanced_context();
1694
1695 // check that callback is provided
1696 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
1697 if (cb == nullptr) {
1698 return check_for_visit(obj);
1699 }
1700
1701 // apply class filter
1702 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
1703 return check_for_visit(obj);
1704 }
1705
1706 // setup the callback wrapper
1707 CallbackWrapper wrapper(tag_map(), obj);
1708
1709 // apply tag filter
1710 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
1711 wrapper.klass_tag(),
1712 context->heap_filter())) {
1713 return check_for_visit(obj);
1714 }
1715
1716 // for arrays we need the length, otherwise -1
1717 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
1718
1719 // invoke the callback
1720 jint res = (*cb)(ref_kind,
1721 nullptr, // referrer info
1722 wrapper.klass_tag(),
1723 0, // referrer_class_tag is 0 for heap root
1724 wrapper.obj_size(),
1725 wrapper.obj_tag_p(),
1726 nullptr, // referrer_tag_p
1727 len,
1728 (void*)user_data());
1729 if (res & JVMTI_VISIT_ABORT) {
1730 return false;// referrer class tag
1731 }
1732 if (res & JVMTI_VISIT_OBJECTS) {
1733 check_for_visit(obj);
1734 }
1735 return true;
1736 }
1737
1738 // report a reference from a thread stack to an object
1739 inline bool CallbackInvoker::invoke_advanced_stack_ref_callback(jvmtiHeapReferenceKind ref_kind,
1740 jlong thread_tag,
1741 jlong tid,
1742 int depth,
1743 jmethodID method,
1744 jlocation bci,
1745 jint slot,
1746 oop obj) {
1747 AdvancedHeapWalkContext* context = advanced_context();
1748
1749 // check that callback is provider
1750 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
1751 if (cb == nullptr) {
1752 return check_for_visit(obj);
1753 }
1754
1755 // apply class filter
1756 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
1757 return check_for_visit(obj);
1758 }
1759
1760 // setup the callback wrapper
1761 CallbackWrapper wrapper(tag_map(), obj);
1762
1763 // apply tag filter
1764 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
1765 wrapper.klass_tag(),
1766 context->heap_filter())) {
1767 return check_for_visit(obj);
1768 }
1769
1770 // setup the referrer info
1771 jvmtiHeapReferenceInfo reference_info;
1772 reference_info.stack_local.thread_tag = thread_tag;
1773 reference_info.stack_local.thread_id = tid;
1774 reference_info.stack_local.depth = depth;
1775 reference_info.stack_local.method = method;
1776 reference_info.stack_local.location = bci;
1777 reference_info.stack_local.slot = slot;
1778
1779 // for arrays we need the length, otherwise -1
1780 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
1781
1782 // call into the agent
1783 int res = (*cb)(ref_kind,
1784 &reference_info,
1785 wrapper.klass_tag(),
1786 0, // referrer_class_tag is 0 for heap root (stack)
1787 wrapper.obj_size(),
1788 wrapper.obj_tag_p(),
1789 nullptr, // referrer_tag is 0 for root
1790 len,
1791 (void*)user_data());
1792
1793 if (res & JVMTI_VISIT_ABORT) {
1794 return false;
1795 }
1796 if (res & JVMTI_VISIT_OBJECTS) {
1797 check_for_visit(obj);
1798 }
1799 return true;
1800 }
1801
1802 // This mask is used to pass reference_info to a jvmtiHeapReferenceCallback
1803 // only for ref_kinds defined by the JVM TI spec. Otherwise, null is passed.
1804 #define REF_INFO_MASK ((1 << JVMTI_HEAP_REFERENCE_FIELD) \
1805 | (1 << JVMTI_HEAP_REFERENCE_STATIC_FIELD) \
1806 | (1 << JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT) \
1807 | (1 << JVMTI_HEAP_REFERENCE_CONSTANT_POOL) \
1808 | (1 << JVMTI_HEAP_REFERENCE_STACK_LOCAL) \
1809 | (1 << JVMTI_HEAP_REFERENCE_JNI_LOCAL))
1810
1811 // invoke the object reference callback to report a reference
1812 inline bool CallbackInvoker::invoke_advanced_object_reference_callback(jvmtiHeapReferenceKind ref_kind,
1813 oop referrer,
1814 oop obj,
1815 jint index)
1816 {
1817 // field index is only valid field in reference_info
1818 static jvmtiHeapReferenceInfo reference_info = { 0 };
1819
1820 AdvancedHeapWalkContext* context = advanced_context();
1821
1822 // check that callback is provider
1823 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
1824 if (cb == nullptr) {
1825 return check_for_visit(obj);
1826 }
1827
1828 // apply class filter
1829 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
1830 return check_for_visit(obj);
1831 }
1832
1833 // setup the callback wrapper
1834 TwoOopCallbackWrapper wrapper(tag_map(), referrer, obj);
1835
1836 // apply tag filter
1837 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
1838 wrapper.klass_tag(),
1839 context->heap_filter())) {
1840 return check_for_visit(obj);
1841 }
1842
1843 // field index is only valid field in reference_info
1844 reference_info.field.index = index;
1845
1846 // for arrays we need the length, otherwise -1
1847 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
1848
1849 // invoke the callback
1850 int res = (*cb)(ref_kind,
1851 (REF_INFO_MASK & (1 << ref_kind)) ? &reference_info : nullptr,
1852 wrapper.klass_tag(),
1853 wrapper.referrer_klass_tag(),
1854 wrapper.obj_size(),
1855 wrapper.obj_tag_p(),
1856 wrapper.referrer_tag_p(),
1857 len,
1858 (void*)user_data());
1859
1860 if (res & JVMTI_VISIT_ABORT) {
1861 return false;
1862 }
1863 if (res & JVMTI_VISIT_OBJECTS) {
1864 check_for_visit(obj);
1865 }
1866 return true;
1867 }
1868
1869 // report a "simple root"
1870 inline bool CallbackInvoker::report_simple_root(jvmtiHeapReferenceKind kind, oop obj) {
1871 assert(kind != JVMTI_HEAP_REFERENCE_STACK_LOCAL &&
1872 kind != JVMTI_HEAP_REFERENCE_JNI_LOCAL, "not a simple root");
1873
1874 if (is_basic_heap_walk()) {
1875 // map to old style root kind
1876 jvmtiHeapRootKind root_kind = toJvmtiHeapRootKind(kind);
1877 return invoke_basic_heap_root_callback(root_kind, obj);
1878 } else {
1879 assert(is_advanced_heap_walk(), "wrong heap walk type");
1880 return invoke_advanced_heap_root_callback(kind, obj);
1881 }
1882 }
1883
1884
1885 // invoke the primitive array values
1886 inline bool CallbackInvoker::report_primitive_array_values(oop obj) {
1887 assert(obj->is_typeArray(), "not a primitive array");
1888
1889 AdvancedHeapWalkContext* context = advanced_context();
1890 assert(context->array_primitive_value_callback() != nullptr, "no callback");
1891
1892 // apply class filter
1893 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
1894 return true;
1895 }
1896
1897 CallbackWrapper wrapper(tag_map(), obj);
1898
1899 // apply tag filter
1900 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
1901 wrapper.klass_tag(),
1902 context->heap_filter())) {
1903 return true;
1904 }
1905
1906 // invoke the callback
1907 int res = invoke_array_primitive_value_callback(context->array_primitive_value_callback(),
1908 &wrapper,
1909 obj,
1910 (void*)user_data());
1911 return (!(res & JVMTI_VISIT_ABORT));
1912 }
1913
1914 // invoke the string value callback
1915 inline bool CallbackInvoker::report_string_value(oop str) {
1916 assert(str->klass() == vmClasses::String_klass(), "not a string");
1917
1918 AdvancedHeapWalkContext* context = advanced_context();
1919 assert(context->string_primitive_value_callback() != nullptr, "no callback");
1920
1921 // apply class filter
1922 if (is_filtered_by_klass_filter(str, context->klass_filter())) {
1923 return true;
1924 }
1925
1926 CallbackWrapper wrapper(tag_map(), str);
1927
1928 // apply tag filter
1929 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
1930 wrapper.klass_tag(),
1931 context->heap_filter())) {
1932 return true;
1933 }
1934
1935 // invoke the callback
1936 int res = invoke_string_value_callback(context->string_primitive_value_callback(),
1937 &wrapper,
1938 str,
1939 (void*)user_data());
1940 return (!(res & JVMTI_VISIT_ABORT));
1941 }
1942
1943 // invoke the primitive field callback
1944 inline bool CallbackInvoker::report_primitive_field(jvmtiHeapReferenceKind ref_kind,
1945 oop obj,
1946 jint index,
1947 address addr,
1948 char type)
1949 {
1950 // for primitive fields only the index will be set
1951 static jvmtiHeapReferenceInfo reference_info = { 0 };
1952
1953 AdvancedHeapWalkContext* context = advanced_context();
1954 assert(context->primitive_field_callback() != nullptr, "no callback");
1955
1956 // apply class filter
1957 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
1958 return true;
1959 }
1960
1961 CallbackWrapper wrapper(tag_map(), obj);
1962
1963 // apply tag filter
1964 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
1965 wrapper.klass_tag(),
1973 // map the type
1974 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
1975
1976 // setup the jvalue
1977 jvalue value;
1978 copy_to_jvalue(&value, addr, value_type);
1979
1980 jvmtiPrimitiveFieldCallback cb = context->primitive_field_callback();
1981 int res = (*cb)(ref_kind,
1982 &reference_info,
1983 wrapper.klass_tag(),
1984 wrapper.obj_tag_p(),
1985 value,
1986 value_type,
1987 (void*)user_data());
1988 return (!(res & JVMTI_VISIT_ABORT));
1989 }
1990
1991
1992 // instance field
1993 inline bool CallbackInvoker::report_primitive_instance_field(oop obj,
1994 jint index,
1995 address value,
1996 char type) {
1997 return report_primitive_field(JVMTI_HEAP_REFERENCE_FIELD,
1998 obj,
1999 index,
2000 value,
2001 type);
2002 }
2003
2004 // static field
2005 inline bool CallbackInvoker::report_primitive_static_field(oop obj,
2006 jint index,
2007 address value,
2008 char type) {
2009 return report_primitive_field(JVMTI_HEAP_REFERENCE_STATIC_FIELD,
2010 obj,
2011 index,
2012 value,
2013 type);
2014 }
2015
2016 // report a JNI local (root object) to the profiler
2017 inline bool CallbackInvoker::report_jni_local_root(jlong thread_tag, jlong tid, jint depth, jmethodID m, oop obj) {
2018 if (is_basic_heap_walk()) {
2019 return invoke_basic_stack_ref_callback(JVMTI_HEAP_ROOT_JNI_LOCAL,
2020 thread_tag,
2021 depth,
2022 m,
2023 -1,
2024 obj);
2025 } else {
2026 return invoke_advanced_stack_ref_callback(JVMTI_HEAP_REFERENCE_JNI_LOCAL,
2027 thread_tag, tid,
2028 depth,
2029 m,
2030 (jlocation)-1,
2031 -1,
2032 obj);
2033 }
2034 }
2035
2036
2037 // report a local (stack reference, root object)
2038 inline bool CallbackInvoker::report_stack_ref_root(jlong thread_tag,
2039 jlong tid,
2040 jint depth,
2041 jmethodID method,
2042 jlocation bci,
2043 jint slot,
2044 oop obj) {
2045 if (is_basic_heap_walk()) {
2046 return invoke_basic_stack_ref_callback(JVMTI_HEAP_ROOT_STACK_LOCAL,
2047 thread_tag,
2048 depth,
2049 method,
2050 slot,
2051 obj);
2052 } else {
2053 return invoke_advanced_stack_ref_callback(JVMTI_HEAP_REFERENCE_STACK_LOCAL,
2054 thread_tag,
2055 tid,
2056 depth,
2057 method,
2058 bci,
2059 slot,
2060 obj);
2061 }
2062 }
2063
2064 // report an object referencing a class.
2065 inline bool CallbackInvoker::report_class_reference(oop referrer, oop referree) {
2066 if (is_basic_heap_walk()) {
2067 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS, referrer, referree, -1);
2068 } else {
2069 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CLASS, referrer, referree, -1);
2070 }
2071 }
2072
2073 // report a class referencing its class loader.
2074 inline bool CallbackInvoker::report_class_loader_reference(oop referrer, oop referree) {
2075 if (is_basic_heap_walk()) {
2076 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS_LOADER, referrer, referree, -1);
2077 } else {
2078 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CLASS_LOADER, referrer, referree, -1);
2079 }
2080 }
2081
2082 // report a class referencing its signers.
2083 inline bool CallbackInvoker::report_signers_reference(oop referrer, oop referree) {
2084 if (is_basic_heap_walk()) {
2085 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_SIGNERS, referrer, referree, -1);
2086 } else {
2087 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_SIGNERS, referrer, referree, -1);
2088 }
2089 }
2090
2091 // report a class referencing its protection domain..
2092 inline bool CallbackInvoker::report_protection_domain_reference(oop referrer, oop referree) {
2093 if (is_basic_heap_walk()) {
2094 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_PROTECTION_DOMAIN, referrer, referree, -1);
2095 } else {
2096 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_PROTECTION_DOMAIN, referrer, referree, -1);
2097 }
2098 }
2099
2100 // report a class referencing its superclass.
2101 inline bool CallbackInvoker::report_superclass_reference(oop referrer, oop referree) {
2102 if (is_basic_heap_walk()) {
2103 // Send this to be consistent with past implementation
2104 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS, referrer, referree, -1);
2105 } else {
2106 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_SUPERCLASS, referrer, referree, -1);
2107 }
2108 }
2109
2110 // report a class referencing one of its interfaces.
2111 inline bool CallbackInvoker::report_interface_reference(oop referrer, oop referree) {
2112 if (is_basic_heap_walk()) {
2113 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_INTERFACE, referrer, referree, -1);
2114 } else {
2115 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_INTERFACE, referrer, referree, -1);
2116 }
2117 }
2118
2119 // report a class referencing one of its static fields.
2120 inline bool CallbackInvoker::report_static_field_reference(oop referrer, oop referree, jint slot) {
2121 if (is_basic_heap_walk()) {
2122 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_STATIC_FIELD, referrer, referree, slot);
2123 } else {
2124 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_STATIC_FIELD, referrer, referree, slot);
2125 }
2126 }
2127
2128 // report an array referencing an element object
2129 inline bool CallbackInvoker::report_array_element_reference(oop referrer, oop referree, jint index) {
2130 if (is_basic_heap_walk()) {
2131 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_ARRAY_ELEMENT, referrer, referree, index);
2132 } else {
2133 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT, referrer, referree, index);
2134 }
2135 }
2136
2137 // report an object referencing an instance field object
2138 inline bool CallbackInvoker::report_field_reference(oop referrer, oop referree, jint slot) {
2139 if (is_basic_heap_walk()) {
2140 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_FIELD, referrer, referree, slot);
2141 } else {
2142 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_FIELD, referrer, referree, slot);
2143 }
2144 }
2145
2146 // report an array referencing an element object
2147 inline bool CallbackInvoker::report_constant_pool_reference(oop referrer, oop referree, jint index) {
2148 if (is_basic_heap_walk()) {
2149 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CONSTANT_POOL, referrer, referree, index);
2150 } else {
2151 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CONSTANT_POOL, referrer, referree, index);
2152 }
2153 }
2154
2155 // A supporting closure used to process simple roots
2156 class SimpleRootsClosure : public OopClosure {
2157 private:
2158 jvmtiHeapReferenceKind _kind;
2159 bool _continue;
2160
2161 jvmtiHeapReferenceKind root_kind() { return _kind; }
2162
2163 public:
2164 void set_kind(jvmtiHeapReferenceKind kind) {
2165 _kind = kind;
2166 _continue = true;
2167 }
2287
2288 public:
2289 StackRefCollector(JvmtiTagMap* tag_map, JNILocalRootsClosure* blk, JavaThread* java_thread)
2290 : _tag_map(tag_map), _blk(blk), _java_thread(java_thread),
2291 _threadObj(nullptr), _thread_tag(0), _tid(0),
2292 _is_top_frame(true), _depth(0), _last_entry_frame(nullptr)
2293 {
2294 }
2295
2296 bool set_thread(oop o);
2297 // Sets the thread and reports the reference to it with the specified kind.
2298 bool set_thread(jvmtiHeapReferenceKind kind, oop o);
2299
2300 bool do_frame(vframe* vf);
2301 // Handles frames until vf->sender() is null.
2302 bool process_frames(vframe* vf);
2303 };
2304
2305 bool StackRefCollector::set_thread(oop o) {
2306 _threadObj = o;
2307 _thread_tag = tag_for(_tag_map, _threadObj);
2308 _tid = java_lang_Thread::thread_id(_threadObj);
2309
2310 _is_top_frame = true;
2311 _depth = 0;
2312 _last_entry_frame = nullptr;
2313
2314 return true;
2315 }
2316
2317 bool StackRefCollector::set_thread(jvmtiHeapReferenceKind kind, oop o) {
2318 return set_thread(o)
2319 && CallbackInvoker::report_simple_root(kind, _threadObj);
2320 }
2321
2322 bool StackRefCollector::report_java_stack_refs(StackValueCollection* values, jmethodID method, jlocation bci, jint slot_offset) {
2323 for (int index = 0; index < values->size(); index++) {
2324 if (values->at(index)->type() == T_OBJECT) {
2325 oop obj = values->obj_at(index)();
2326 if (obj == nullptr) {
2327 continue;
2420 return true;
2421 }
2422
2423
2424 // A VM operation to iterate over objects that are reachable from
2425 // a set of roots or an initial object.
2426 //
2427 // For VM_HeapWalkOperation the set of roots used is :-
2428 //
2429 // - All JNI global references
2430 // - All inflated monitors
2431 // - All classes loaded by the boot class loader (or all classes
2432 // in the event that class unloading is disabled)
2433 // - All java threads
2434 // - For each java thread then all locals and JNI local references
2435 // on the thread's execution stack
2436 // - All visible/explainable objects from Universes::oops_do
2437 //
2438 class VM_HeapWalkOperation: public VM_Operation {
2439 private:
2440 enum {
2441 initial_visit_stack_size = 4000
2442 };
2443
2444 bool _is_advanced_heap_walk; // indicates FollowReferences
2445 JvmtiTagMap* _tag_map;
2446 Handle _initial_object;
2447 GrowableArray<oop>* _visit_stack; // the visit stack
2448
2449 JVMTIBitSet _bitset;
2450
2451 // Dead object tags in JvmtiTagMap
2452 GrowableArray<jlong>* _dead_objects;
2453
2454 bool _following_object_refs; // are we following object references
2455
2456 bool _reporting_primitive_fields; // optional reporting
2457 bool _reporting_primitive_array_values;
2458 bool _reporting_string_values;
2459
2460 GrowableArray<oop>* create_visit_stack() {
2461 return new (mtServiceability) GrowableArray<oop>(initial_visit_stack_size, mtServiceability);
2462 }
2463
2464 // accessors
2465 bool is_advanced_heap_walk() const { return _is_advanced_heap_walk; }
2466 JvmtiTagMap* tag_map() const { return _tag_map; }
2467 Handle initial_object() const { return _initial_object; }
2468
2469 bool is_following_references() const { return _following_object_refs; }
2470
2471 bool is_reporting_primitive_fields() const { return _reporting_primitive_fields; }
2472 bool is_reporting_primitive_array_values() const { return _reporting_primitive_array_values; }
2473 bool is_reporting_string_values() const { return _reporting_string_values; }
2474
2475 GrowableArray<oop>* visit_stack() const { return _visit_stack; }
2476
2477 // iterate over the various object types
2478 inline bool iterate_over_array(oop o);
2479 inline bool iterate_over_type_array(oop o);
2480 inline bool iterate_over_class(oop o);
2481 inline bool iterate_over_object(oop o);
2482
2483 // root collection
2484 inline bool collect_simple_roots();
2485 inline bool collect_stack_roots();
2486 inline bool collect_stack_refs(JavaThread* java_thread, JNILocalRootsClosure* blk);
2487 inline bool collect_vthread_stack_refs(oop vt);
2488
2489 // visit an object
2490 inline bool visit(oop o);
2491
2492 public:
2493 VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2494 Handle initial_object,
2495 BasicHeapWalkContext callbacks,
2496 const void* user_data,
2497 GrowableArray<jlong>* objects);
2498
2499 VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2500 Handle initial_object,
2501 AdvancedHeapWalkContext callbacks,
2502 const void* user_data,
2503 GrowableArray<jlong>* objects);
2504
2505 ~VM_HeapWalkOperation();
2506
2507 VMOp_Type type() const { return VMOp_HeapWalkOperation; }
2508 void doit();
2509 };
2510
2511
2512 VM_HeapWalkOperation::VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2513 Handle initial_object,
2514 BasicHeapWalkContext callbacks,
2515 const void* user_data,
2516 GrowableArray<jlong>* objects) {
2517 _is_advanced_heap_walk = false;
2518 _tag_map = tag_map;
2519 _initial_object = initial_object;
2520 _following_object_refs = (callbacks.object_ref_callback() != nullptr);
2521 _reporting_primitive_fields = false;
2522 _reporting_primitive_array_values = false;
2523 _reporting_string_values = false;
2524 _visit_stack = create_visit_stack();
2525 _dead_objects = objects;
2526
2527 CallbackInvoker::initialize_for_basic_heap_walk(tag_map, _visit_stack, user_data, callbacks, &_bitset);
2528 }
2529
2530 VM_HeapWalkOperation::VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2531 Handle initial_object,
2532 AdvancedHeapWalkContext callbacks,
2533 const void* user_data,
2534 GrowableArray<jlong>* objects) {
2535 _is_advanced_heap_walk = true;
2536 _tag_map = tag_map;
2537 _initial_object = initial_object;
2538 _following_object_refs = true;
2539 _reporting_primitive_fields = (callbacks.primitive_field_callback() != nullptr);;
2540 _reporting_primitive_array_values = (callbacks.array_primitive_value_callback() != nullptr);;
2541 _reporting_string_values = (callbacks.string_primitive_value_callback() != nullptr);;
2542 _visit_stack = create_visit_stack();
2543 _dead_objects = objects;
2544 CallbackInvoker::initialize_for_advanced_heap_walk(tag_map, _visit_stack, user_data, callbacks, &_bitset);
2545 }
2546
2547 VM_HeapWalkOperation::~VM_HeapWalkOperation() {
2548 if (_following_object_refs) {
2549 assert(_visit_stack != nullptr, "checking");
2550 delete _visit_stack;
2551 _visit_stack = nullptr;
2552 }
2553 }
2554
2555 // an array references its class and has a reference to
2556 // each element in the array
2557 inline bool VM_HeapWalkOperation::iterate_over_array(oop o) {
2558 objArrayOop array = objArrayOop(o);
2559
2560 // array reference to its class
2561 oop mirror = ObjArrayKlass::cast(array->klass())->java_mirror();
2562 if (!CallbackInvoker::report_class_reference(o, mirror)) {
2563 return false;
2564 }
2565
2566 // iterate over the array and report each reference to a
2567 // non-null element
2568 for (int index=0; index<array->length(); index++) {
2569 oop elem = array->obj_at(index);
2570 if (elem == nullptr) {
2571 continue;
2572 }
2573
2574 // report the array reference o[index] = elem
2575 if (!CallbackInvoker::report_array_element_reference(o, elem, index)) {
2576 return false;
2577 }
2578 }
2579 return true;
2580 }
2581
2582 // a type array references its class
2583 inline bool VM_HeapWalkOperation::iterate_over_type_array(oop o) {
2584 Klass* k = o->klass();
2585 oop mirror = k->java_mirror();
2586 if (!CallbackInvoker::report_class_reference(o, mirror)) {
2587 return false;
2588 }
2589
2590 // report the array contents if required
2591 if (is_reporting_primitive_array_values()) {
2592 if (!CallbackInvoker::report_primitive_array_values(o)) {
2593 return false;
2594 }
2595 }
2596 return true;
2597 }
2598
2599 #ifdef ASSERT
2600 // verify that a static oop field is in range
2601 static inline bool verify_static_oop(InstanceKlass* ik,
2602 oop mirror, int offset) {
2603 address obj_p = cast_from_oop<address>(mirror) + offset;
2604 address start = (address)InstanceMirrorKlass::start_of_static_fields(mirror);
2605 address end = start + (java_lang_Class::static_oop_field_count(mirror) * heapOopSize);
2606 assert(end >= start, "sanity check");
2607
2608 if (obj_p >= start && obj_p < end) {
2609 return true;
2610 } else {
2611 return false;
2612 }
2613 }
2614 #endif // #ifdef ASSERT
2615
2616 // a class references its super class, interfaces, class loader, ...
2617 // and finally its static fields
2618 inline bool VM_HeapWalkOperation::iterate_over_class(oop java_class) {
2619 int i;
2620 Klass* klass = java_lang_Class::as_Klass(java_class);
2621
2622 if (klass->is_instance_klass()) {
2623 InstanceKlass* ik = InstanceKlass::cast(klass);
2624
2625 // Ignore the class if it hasn't been initialized yet
2626 if (!ik->is_linked()) {
2627 return true;
2628 }
2629
2630 // get the java mirror
2631 oop mirror = klass->java_mirror();
2632
2633 // super (only if something more interesting than java.lang.Object)
2634 InstanceKlass* super_klass = ik->super();
2635 if (super_klass != nullptr && super_klass != vmClasses::Object_klass()) {
2636 oop super_oop = super_klass->java_mirror();
2637 if (!CallbackInvoker::report_superclass_reference(mirror, super_oop)) {
2638 return false;
2639 }
2640 }
2641
2642 // class loader
2643 oop cl = ik->class_loader();
2644 if (cl != nullptr) {
2645 if (!CallbackInvoker::report_class_loader_reference(mirror, cl)) {
2646 return false;
2647 }
2648 }
2649
2650 // protection domain
2651 oop pd = ik->protection_domain();
2700 // (These will already have been reported as references from the constant pool
2701 // but are specified by IterateOverReachableObjects and must be reported).
2702 Array<InstanceKlass*>* interfaces = ik->local_interfaces();
2703 for (i = 0; i < interfaces->length(); i++) {
2704 oop interf = interfaces->at(i)->java_mirror();
2705 if (interf == nullptr) {
2706 continue;
2707 }
2708 if (!CallbackInvoker::report_interface_reference(mirror, interf)) {
2709 return false;
2710 }
2711 }
2712
2713 // iterate over the static fields
2714
2715 ClassFieldMap* field_map = ClassFieldMap::create_map_of_static_fields(klass);
2716 for (i=0; i<field_map->field_count(); i++) {
2717 ClassFieldDescriptor* field = field_map->field_at(i);
2718 char type = field->field_type();
2719 if (!is_primitive_field_type(type)) {
2720 oop fld_o = mirror->obj_field(field->field_offset());
2721 assert(verify_static_oop(ik, mirror, field->field_offset()), "sanity check");
2722 if (fld_o != nullptr) {
2723 int slot = field->field_index();
2724 if (!CallbackInvoker::report_static_field_reference(mirror, fld_o, slot)) {
2725 delete field_map;
2726 return false;
2727 }
2728 }
2729 } else {
2730 if (is_reporting_primitive_fields()) {
2731 address addr = cast_from_oop<address>(mirror) + field->field_offset();
2732 int slot = field->field_index();
2733 if (!CallbackInvoker::report_primitive_static_field(mirror, slot, addr, type)) {
2734 delete field_map;
2735 return false;
2736 }
2737 }
2738 }
2739 }
2740 delete field_map;
2741
2742 return true;
2743 }
2744
2745 return true;
2746 }
2747
2748 // an object references a class and its instance fields
2749 // (static fields are ignored here as we report these as
2750 // references from the class).
2751 inline bool VM_HeapWalkOperation::iterate_over_object(oop o) {
2752 // reference to the class
2753 if (!CallbackInvoker::report_class_reference(o, o->klass()->java_mirror())) {
2754 return false;
2755 }
2756
2757 // iterate over instance fields
2758 ClassFieldMap* field_map = JvmtiCachedClassFieldMap::get_map_of_instance_fields(o);
2759 for (int i=0; i<field_map->field_count(); i++) {
2760 ClassFieldDescriptor* field = field_map->field_at(i);
2761 char type = field->field_type();
2762 if (!is_primitive_field_type(type)) {
2763 oop fld_o = o->obj_field_access<AS_NO_KEEPALIVE | ON_UNKNOWN_OOP_REF>(field->field_offset());
2764 // ignore any objects that aren't visible to profiler
2765 if (fld_o != nullptr) {
2766 assert(Universe::heap()->is_in(fld_o), "unsafe code should not "
2767 "have references to Klass* anymore");
2768 int slot = field->field_index();
2769 if (!CallbackInvoker::report_field_reference(o, fld_o, slot)) {
2770 return false;
2771 }
2772 }
2773 } else {
2774 if (is_reporting_primitive_fields()) {
2775 // primitive instance field
2776 address addr = cast_from_oop<address>(o) + field->field_offset();
2777 int slot = field->field_index();
2778 if (!CallbackInvoker::report_primitive_instance_field(o, slot, addr, type)) {
2779 return false;
2780 }
2781 }
2782 }
2783 }
2784
2785 // if the object is a java.lang.String
2786 if (is_reporting_string_values() &&
2787 o->klass() == vmClasses::String_klass()) {
2788 if (!CallbackInvoker::report_string_value(o)) {
2789 return false;
2790 }
2791 }
2792 return true;
2793 }
2794
2795
2796 // Collects all simple (non-stack) roots except for threads;
2797 // threads are handled in collect_stack_roots() as an optimization.
2798 // if there's a heap root callback provided then the callback is
2799 // invoked for each simple root.
2800 // if an object reference callback is provided then all simple
2801 // roots are pushed onto the marking stack so that they can be
2802 // processed later
2803 //
2804 inline bool VM_HeapWalkOperation::collect_simple_roots() {
2805 SimpleRootsClosure blk;
2806
2807 // JNI globals
2836 // Reports the thread as JVMTI_HEAP_REFERENCE_THREAD,
2837 // walks the stack of the thread, finds all references (locals
2838 // and JNI calls) and reports these as stack references.
2839 inline bool VM_HeapWalkOperation::collect_stack_refs(JavaThread* java_thread,
2840 JNILocalRootsClosure* blk)
2841 {
2842 oop threadObj = java_thread->threadObj();
2843 oop mounted_vt = java_thread->is_vthread_mounted() ? java_thread->vthread() : nullptr;
2844 if (mounted_vt != nullptr && !JvmtiEnvBase::is_vthread_alive(mounted_vt)) {
2845 mounted_vt = nullptr;
2846 }
2847 assert(threadObj != nullptr, "sanity check");
2848
2849 StackRefCollector stack_collector(tag_map(), blk, java_thread);
2850
2851 if (!java_thread->has_last_Java_frame()) {
2852 if (!stack_collector.set_thread(JVMTI_HEAP_REFERENCE_THREAD, threadObj)) {
2853 return false;
2854 }
2855 // no last java frame but there may be JNI locals
2856 blk->set_context(tag_for(_tag_map, threadObj), java_lang_Thread::thread_id(threadObj), 0, (jmethodID)nullptr);
2857 java_thread->active_handles()->oops_do(blk);
2858 return !blk->stopped();
2859 }
2860 // vframes are resource allocated
2861 Thread* current_thread = Thread::current();
2862 ResourceMark rm(current_thread);
2863 HandleMark hm(current_thread);
2864
2865 RegisterMap reg_map(java_thread,
2866 RegisterMap::UpdateMap::include,
2867 RegisterMap::ProcessFrames::include,
2868 RegisterMap::WalkContinuation::include);
2869
2870 // first handle mounted vthread (if any)
2871 if (mounted_vt != nullptr) {
2872 frame f = java_thread->last_frame();
2873 vframe* vf = vframe::new_vframe(&f, ®_map, java_thread);
2874 // report virtual thread as JVMTI_HEAP_REFERENCE_OTHER
2875 if (!stack_collector.set_thread(JVMTI_HEAP_REFERENCE_OTHER, mounted_vt)) {
2876 return false;
2936 RegisterMap reg_map(cont.continuation(), RegisterMap::UpdateMap::include);
2937
2938 JNILocalRootsClosure blk;
2939 // JavaThread is not required for unmounted virtual threads
2940 StackRefCollector stack_collector(tag_map(), &blk, nullptr);
2941 // reference to the vthread is already reported
2942 if (!stack_collector.set_thread(vt)) {
2943 return false;
2944 }
2945
2946 frame fr = chunk->top_frame(®_map);
2947 vframe* vf = vframe::new_vframe(&fr, ®_map, nullptr);
2948 return stack_collector.process_frames(vf);
2949 }
2950
2951 // visit an object
2952 // first mark the object as visited
2953 // second get all the outbound references from this object (in other words, all
2954 // the objects referenced by this object).
2955 //
2956 bool VM_HeapWalkOperation::visit(oop o) {
2957 // mark object as visited
2958 assert(!_bitset.is_marked(o), "can't visit same object more than once");
2959 _bitset.mark_obj(o);
2960
2961 // instance
2962 if (o->is_instance()) {
2963 if (o->klass() == vmClasses::Class_klass()) {
2964 if (!java_lang_Class::is_primitive(o)) {
2965 // a java.lang.Class
2966 return iterate_over_class(o);
2967 }
2968 } else {
2969 // we report stack references only when initial object is not specified
2970 // (in the case we start from heap roots which include platform thread stack references)
2971 if (initial_object().is_null() && java_lang_VirtualThread::is_subclass(o->klass())) {
2972 if (!collect_vthread_stack_refs(o)) {
2973 return false;
2974 }
2975 }
2976 return iterate_over_object(o);
2977 }
2978 }
2979
2980 // object array
2981 if (o->is_objArray()) {
2982 return iterate_over_array(o);
2983 }
2984
2985 // type array
2986 if (o->is_typeArray()) {
2987 return iterate_over_type_array(o);
2988 }
2989
2990 return true;
2991 }
2992
2993 void VM_HeapWalkOperation::doit() {
2994 ResourceMark rm;
2995 ClassFieldMapCacheMark cm;
2996
2997 JvmtiTagMap::check_hashmaps_for_heapwalk(_dead_objects);
2998
2999 assert(visit_stack()->is_empty(), "visit stack must be empty");
3000
3001 // the heap walk starts with an initial object or the heap roots
3002 if (initial_object().is_null()) {
3003 // can result in a big performance boost for an agent that is
3004 // focused on analyzing references in the thread stacks.
3005 if (!collect_stack_roots()) return;
3006
3007 if (!collect_simple_roots()) return;
3008 } else {
3009 visit_stack()->push(initial_object()());
3010 }
3011
3012 // object references required
3013 if (is_following_references()) {
3014
3015 // visit each object until all reachable objects have been
3016 // visited or the callback asked to terminate the iteration.
3017 while (!visit_stack()->is_empty()) {
3018 oop o = visit_stack()->pop();
3019 if (!_bitset.is_marked(o)) {
3020 if (!visit(o)) {
3021 break;
3022 }
3023 }
3024 }
3025 }
3026 }
3027
3028 // iterate over all objects that are reachable from a set of roots
3029 void JvmtiTagMap::iterate_over_reachable_objects(jvmtiHeapRootCallback heap_root_callback,
3030 jvmtiStackReferenceCallback stack_ref_callback,
3031 jvmtiObjectReferenceCallback object_ref_callback,
3032 const void* user_data) {
3033 // VTMS transitions must be disabled before the EscapeBarrier.
3034 MountUnmountDisabler disabler;
3035
3036 JavaThread* jt = JavaThread::current();
3037 EscapeBarrier eb(true, jt);
3038 eb.deoptimize_objects_all_threads();
3039 Arena dead_object_arena(mtServiceability);
3040 GrowableArray<jlong> dead_objects(&dead_object_arena, 10, 0, 0);
3041
3042 {
3043 MutexLocker ml(Heap_lock);
3044 BasicHeapWalkContext context(heap_root_callback, stack_ref_callback, object_ref_callback);
3045 VM_HeapWalkOperation op(this, Handle(), context, user_data, &dead_objects);
3046 VMThread::execute(&op);
3047 }
3048 // Post events outside of Heap_lock
3049 post_dead_objects(&dead_objects);
3050 }
3051
3052 // iterate over all objects that are reachable from a given object
3053 void JvmtiTagMap::iterate_over_objects_reachable_from_object(jobject object,
3054 jvmtiObjectReferenceCallback object_ref_callback,
3055 const void* user_data) {
3056 oop obj = JNIHandles::resolve(object);
3057 Handle initial_object(Thread::current(), obj);
3058
3059 Arena dead_object_arena(mtServiceability);
3060 GrowableArray<jlong> dead_objects(&dead_object_arena, 10, 0, 0);
3061
3062 MountUnmountDisabler disabler;
3063
3064 {
3065 MutexLocker ml(Heap_lock);
3066 BasicHeapWalkContext context(nullptr, nullptr, object_ref_callback);
3067 VM_HeapWalkOperation op(this, initial_object, context, user_data, &dead_objects);
3068 VMThread::execute(&op);
3069 }
3070 // Post events outside of Heap_lock
3071 post_dead_objects(&dead_objects);
3072 }
3073
3074 // follow references from an initial object or the GC roots
3075 void JvmtiTagMap::follow_references(jint heap_filter,
3076 Klass* klass,
3077 jobject object,
3078 const jvmtiHeapCallbacks* callbacks,
3079 const void* user_data)
3080 {
3081 // VTMS transitions must be disabled before the EscapeBarrier.
3082 MountUnmountDisabler disabler;
3083
3084 oop obj = JNIHandles::resolve(object);
3085 JavaThread* jt = JavaThread::current();
3086 Handle initial_object(jt, obj);
3087 // EA based optimizations that are tagged or reachable from initial_object are already reverted.
3088 EscapeBarrier eb(initial_object.is_null() &&
3089 !(heap_filter & JVMTI_HEAP_FILTER_UNTAGGED),
3090 jt);
3091 eb.deoptimize_objects_all_threads();
3092
3093 Arena dead_object_arena(mtServiceability);
3094 GrowableArray<jlong> dead_objects(&dead_object_arena, 10, 0, 0);
3095
3096 {
3097 MutexLocker ml(Heap_lock);
3098 AdvancedHeapWalkContext context(heap_filter, klass, callbacks);
3099 VM_HeapWalkOperation op(this, initial_object, context, user_data, &dead_objects);
3100 VMThread::execute(&op);
3101 }
3102 // Post events outside of Heap_lock
3103 post_dead_objects(&dead_objects);
3104 }
3105
3106 // Verify gc_notification follows set_needs_cleaning.
3107 DEBUG_ONLY(static bool notified_needs_cleaning = false;)
3108
3109 void JvmtiTagMap::set_needs_cleaning() {
3110 assert(SafepointSynchronize::is_at_safepoint(), "called in gc pause");
3111 assert(Thread::current()->is_VM_thread(), "should be the VM thread");
3112 // Can't assert !notified_needs_cleaning; a partial GC might be upgraded
3113 // to a full GC and do this twice without intervening gc_notification.
3114 DEBUG_ONLY(notified_needs_cleaning = true;)
3115
3116 JvmtiEnvIterator it;
3117 for (JvmtiEnv* env = it.first(); env != nullptr; env = it.next(env)) {
3118 JvmtiTagMap* tag_map = env->tag_map_acquire();
3119 if (tag_map != nullptr) {
3120 tag_map->_needs_cleaning = !tag_map->is_empty();
3121 }
|
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/mountUnmountDisabler.hpp"
61 #include "runtime/mutex.hpp"
62 #include "runtime/mutexLocker.hpp"
63 #include "runtime/safepoint.hpp"
64 #include "runtime/threadSMR.hpp"
65 #include "runtime/timerTrace.hpp"
66 #include "runtime/vframe.hpp"
67 #include "runtime/vmOperations.hpp"
68 #include "runtime/vmThread.hpp"
69 #include "utilities/macros.hpp"
70 #include "utilities/objectBitSet.inline.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 count += interfaces->at(i)->java_fields_count();
677
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->super(); super_klass != nullptr; super_klass = super_klass->super()) {
699 index += super_klass->java_fields_count();
700 }
701
702 for (JavaFieldStream fld(ik); !fld.done(); fld.next(), index++) {
703 // ignore instance fields
704 if (!fld.access_flags().is_static()) {
705 continue;
706 }
707 field_map->add(index, fld);
708 }
709
710 return field_map;
711 }
712
713 // Returns a heap allocated ClassFieldMap to describe the instance fields
714 // of the given class. All instance fields are included (this means public
715 // and private fields declared in superclasses too).
716 ClassFieldMap* ClassFieldMap::create_map_of_instance_fields(Klass* k) {
717 InstanceKlass* ik = InstanceKlass::cast(k);
718
719 // create the field map
720 ClassFieldMap* field_map = new ClassFieldMap();
721
722 // fields of the superclasses are reported first, so need to know total field number to calculate field indices
723 int total_field_number = interfaces_field_count(ik);
724 for (InstanceKlass* klass = ik; klass != nullptr; klass = klass->super()) {
725 total_field_number += klass->java_fields_count();
726 }
727
728 for (InstanceKlass* klass = ik; klass != nullptr; klass = klass->super()) {
729 JavaFieldStream fld(klass);
730 int start_index = total_field_number - klass->java_fields_count();
731 for (int index = 0; !fld.done(); fld.next(), index++) {
732 // ignore static fields
733 if (fld.access_flags().is_static()) {
734 continue;
735 }
736 field_map->add(start_index + index, fld);
737 }
738 // update total_field_number for superclass (decrease by the field count in the current class)
739 total_field_number = start_index;
740 }
741
742 return field_map;
743 }
744
745 // Helper class used to cache a ClassFileMap for the instance fields of
746 // a cache. A JvmtiCachedClassFieldMap can be cached by an InstanceKlass during
747 // heap iteration and avoid creating a field map for each object in the heap
748 // (only need to create the map when the first instance of a class is encountered).
749 //
750 class JvmtiCachedClassFieldMap : public CHeapObj<mtInternal> {
751 private:
752 enum {
753 initial_class_count = 200
754 };
755 ClassFieldMap* _field_map;
756
757 ClassFieldMap* field_map() const { return _field_map; }
758
759 JvmtiCachedClassFieldMap(ClassFieldMap* field_map);
760 ~JvmtiCachedClassFieldMap();
761
762 static GrowableArray<InstanceKlass*>* _class_list;
763 static void add_to_class_list(InstanceKlass* ik);
764
765 public:
766 // returns the field map for a given klass (returning map cached
767 // by InstanceKlass if possible
768 static ClassFieldMap* get_map_of_instance_fields(Klass* k);
769
770 // removes the field map from all instanceKlasses - should be
771 // called before VM operation completes
772 static void clear_cache();
773
774 // returns the number of ClassFieldMap cached by instanceKlasses
775 static int cached_field_map_count();
776 };
777
778 GrowableArray<InstanceKlass*>* JvmtiCachedClassFieldMap::_class_list;
779
780 JvmtiCachedClassFieldMap::JvmtiCachedClassFieldMap(ClassFieldMap* field_map) {
781 _field_map = field_map;
782 }
783
784 JvmtiCachedClassFieldMap::~JvmtiCachedClassFieldMap() {
785 if (_field_map != nullptr) {
786 delete _field_map;
787 }
788 }
800 _is_active = true;
801 }
802 ~ClassFieldMapCacheMark() {
803 JvmtiCachedClassFieldMap::clear_cache();
804 _is_active = false;
805 }
806 static bool is_active() { return _is_active; }
807 };
808
809 bool ClassFieldMapCacheMark::_is_active;
810
811 // record that the given InstanceKlass is caching a field map
812 void JvmtiCachedClassFieldMap::add_to_class_list(InstanceKlass* ik) {
813 if (_class_list == nullptr) {
814 _class_list = new (mtServiceability)
815 GrowableArray<InstanceKlass*>(initial_class_count, mtServiceability);
816 }
817 _class_list->push(ik);
818 }
819
820 // returns the instance field map for the given klass
821 // (returns field map cached by the InstanceKlass if possible)
822 ClassFieldMap* JvmtiCachedClassFieldMap::get_map_of_instance_fields(Klass *k) {
823 assert(Thread::current()->is_VM_thread(), "must be VMThread");
824 assert(ClassFieldMapCacheMark::is_active(), "ClassFieldMapCacheMark not active");
825
826 InstanceKlass* ik = InstanceKlass::cast(k);
827
828 // return cached map if possible
829 JvmtiCachedClassFieldMap* cached_map = ik->jvmti_cached_class_field_map();
830 if (cached_map != nullptr) {
831 assert(cached_map->field_map() != nullptr, "missing field list");
832 return cached_map->field_map();
833 } else {
834 ClassFieldMap* field_map = ClassFieldMap::create_map_of_instance_fields(k);
835 cached_map = new JvmtiCachedClassFieldMap(field_map);
836 ik->set_jvmti_cached_class_field_map(cached_map);
837 add_to_class_list(ik);
838 return field_map;
839 }
840 }
841
842 // remove the fields maps cached from all instanceKlasses
843 void JvmtiCachedClassFieldMap::clear_cache() {
844 assert(Thread::current()->is_VM_thread(), "must be VMThread");
845 if (_class_list != nullptr) {
846 for (int i = 0; i < _class_list->length(); i++) {
847 InstanceKlass* ik = _class_list->at(i);
848 JvmtiCachedClassFieldMap* cached_map = ik->jvmti_cached_class_field_map();
849 assert(cached_map != nullptr, "should not be null");
850 ik->set_jvmti_cached_class_field_map(nullptr);
851 delete cached_map; // deletes the encapsulated field map
852 }
853 delete _class_list;
854 _class_list = nullptr;
866 int heap_filter) {
867 // apply the heap filter
868 if (obj_tag != 0) {
869 // filter out tagged objects
870 if (heap_filter & JVMTI_HEAP_FILTER_TAGGED) return true;
871 } else {
872 // filter out untagged objects
873 if (heap_filter & JVMTI_HEAP_FILTER_UNTAGGED) return true;
874 }
875 if (klass_tag != 0) {
876 // filter out objects with tagged classes
877 if (heap_filter & JVMTI_HEAP_FILTER_CLASS_TAGGED) return true;
878 } else {
879 // filter out objects with untagged classes.
880 if (heap_filter & JVMTI_HEAP_FILTER_CLASS_UNTAGGED) return true;
881 }
882 return false;
883 }
884
885 // helper function to indicate if an object is filtered by a klass filter
886 static inline bool is_filtered_by_klass_filter(const JvmtiHeapwalkObject& obj, Klass* klass_filter) {
887 if (klass_filter != nullptr) {
888 if (obj.klass() != klass_filter) {
889 return true;
890 }
891 }
892 return false;
893 }
894
895 // helper function to tell if a field is a primitive field or not
896 static inline bool is_primitive_field_type(char type) {
897 return (type != JVM_SIGNATURE_CLASS && type != JVM_SIGNATURE_ARRAY);
898 }
899
900 // helper function to copy the value from location addr to jvalue.
901 static inline void copy_to_jvalue(jvalue *v, address addr, jvmtiPrimitiveType value_type) {
902 switch (value_type) {
903 case JVMTI_PRIMITIVE_TYPE_BOOLEAN : { v->z = *(jboolean*)addr; break; }
904 case JVMTI_PRIMITIVE_TYPE_BYTE : { v->b = *(jbyte*)addr; break; }
905 case JVMTI_PRIMITIVE_TYPE_CHAR : { v->c = *(jchar*)addr; break; }
906 case JVMTI_PRIMITIVE_TYPE_SHORT : { v->s = *(jshort*)addr; break; }
907 case JVMTI_PRIMITIVE_TYPE_INT : { v->i = *(jint*)addr; break; }
908 case JVMTI_PRIMITIVE_TYPE_LONG : { v->j = *(jlong*)addr; break; }
909 case JVMTI_PRIMITIVE_TYPE_FLOAT : { v->f = *(jfloat*)addr; break; }
910 case JVMTI_PRIMITIVE_TYPE_DOUBLE : { v->d = *(jdouble*)addr; break; }
911 default: ShouldNotReachHere();
912 }
913 }
914
915 // helper function to invoke string primitive value callback
916 // returns visit control flags
917 static jint invoke_string_value_callback(jvmtiStringPrimitiveValueCallback cb,
918 CallbackWrapper* wrapper,
919 const JvmtiHeapwalkObject& obj,
920 void* user_data)
921 {
922 assert(!obj.is_flat(), "cannot be flat");
923 oop str = obj.obj();
924 assert(str->klass() == vmClasses::String_klass(), "not a string");
925
926 typeArrayOop s_value = java_lang_String::value(str);
927
928 // JDK-6584008: the value field may be null if a String instance is
929 // partially constructed.
930 if (s_value == nullptr) {
931 return 0;
932 }
933 // get the string value and length
934 // (string value may be offset from the base)
935 int s_len = java_lang_String::length(str);
936 bool is_latin1 = java_lang_String::is_latin1(str);
937 jchar* value;
938 if (s_len > 0) {
939 if (!is_latin1) {
940 value = s_value->char_at_addr(0);
941 } else {
942 // Inflate latin1 encoded string to UTF16
943 jchar* buf = NEW_C_HEAP_ARRAY(jchar, s_len, mtInternal);
952 }
953
954 // invoke the callback
955 jint res = (*cb)(wrapper->klass_tag(),
956 wrapper->obj_size(),
957 wrapper->obj_tag_p(),
958 value,
959 (jint)s_len,
960 user_data);
961
962 if (is_latin1 && s_len > 0) {
963 FREE_C_HEAP_ARRAY(jchar, value);
964 }
965 return res;
966 }
967
968 // helper function to invoke string primitive value callback
969 // returns visit control flags
970 static jint invoke_array_primitive_value_callback(jvmtiArrayPrimitiveValueCallback cb,
971 CallbackWrapper* wrapper,
972 const JvmtiHeapwalkObject& obj,
973 void* user_data)
974 {
975 assert(!obj.is_flat(), "cannot be flat");
976 assert(obj.obj()->is_typeArray(), "not a primitive array");
977
978 // get base address of first element
979 typeArrayOop array = typeArrayOop(obj.obj());
980 BasicType type = TypeArrayKlass::cast(array->klass())->element_type();
981 void* elements = array->base(type);
982
983 // jvmtiPrimitiveType is defined so this mapping is always correct
984 jvmtiPrimitiveType elem_type = (jvmtiPrimitiveType)type2char(type);
985
986 return (*cb)(wrapper->klass_tag(),
987 wrapper->obj_size(),
988 wrapper->obj_tag_p(),
989 (jint)array->length(),
990 elem_type,
991 elements,
992 user_data);
993 }
994
995 // helper function to invoke the primitive field callback for all static fields
996 // of a given class
997 static jint invoke_primitive_field_callback_for_static_fields
998 (CallbackWrapper* wrapper,
999 oop obj,
1049 &reference_info,
1050 wrapper->klass_tag(),
1051 wrapper->obj_tag_p(),
1052 value,
1053 value_type,
1054 user_data);
1055 if (res & JVMTI_VISIT_ABORT) {
1056 delete field_map;
1057 return res;
1058 }
1059 }
1060
1061 delete field_map;
1062 return 0;
1063 }
1064
1065 // helper function to invoke the primitive field callback for all instance fields
1066 // of a given object
1067 static jint invoke_primitive_field_callback_for_instance_fields(
1068 CallbackWrapper* wrapper,
1069 const JvmtiHeapwalkObject& obj,
1070 jvmtiPrimitiveFieldCallback cb,
1071 void* user_data)
1072 {
1073 // for instance fields only the index will be set
1074 static jvmtiHeapReferenceInfo reference_info = { 0 };
1075
1076 // get the map of the instance fields
1077 ClassFieldMap* fields = JvmtiCachedClassFieldMap::get_map_of_instance_fields(obj.klass());
1078
1079 // invoke the callback for each instance primitive field
1080 for (int i=0; i<fields->field_count(); i++) {
1081 ClassFieldDescriptor* field = fields->field_at(i);
1082
1083 // ignore non-primitive fields
1084 char type = field->field_type();
1085 if (!is_primitive_field_type(type)) {
1086 continue;
1087 }
1088 // one-to-one mapping
1089 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
1090
1091 // get field value
1092 address addr = cast_from_oop<address>(obj.obj()) + obj.offset() + field->field_offset();
1093 jvalue value;
1094 copy_to_jvalue(&value, addr, value_type);
1095
1096 // field index
1097 reference_info.field.index = field->field_index();
1098
1099 // invoke the callback
1100 jint res = (*cb)(JVMTI_HEAP_REFERENCE_FIELD,
1101 &reference_info,
1102 wrapper->klass_tag(),
1103 wrapper->obj_tag_p(),
1104 value,
1105 value_type,
1106 user_data);
1107 if (res & JVMTI_VISIT_ABORT) {
1108 return res;
1109 }
1110 }
1111 return 0;
1112 }
1186
1187 // invoked for each object in the heap
1188 void IterateOverHeapObjectClosure::do_object(oop o) {
1189 assert(o != nullptr, "Heap iteration should never produce null!");
1190 // check if iteration has been halted
1191 if (is_iteration_aborted()) return;
1192
1193 // instanceof check when filtering by klass
1194 if (klass() != nullptr && !o->is_a(klass())) {
1195 return;
1196 }
1197
1198 // skip if object is a dormant shared object whose mirror hasn't been loaded
1199 if (o->klass()->java_mirror() == nullptr) {
1200 log_debug(aot, heap)("skipped dormant archived object " INTPTR_FORMAT " (%s)", p2i(o),
1201 o->klass()->external_name());
1202 return;
1203 }
1204
1205 // prepare for the calllback
1206 JvmtiHeapwalkObject wrapper_obj(o);
1207 CallbackWrapper wrapper(tag_map(), wrapper_obj);
1208
1209 // if the object is tagged and we're only interested in untagged objects
1210 // then don't invoke the callback. Similarly, if the object is untagged
1211 // and we're only interested in tagged objects we skip the callback.
1212 if (wrapper.obj_tag() != 0) {
1213 if (object_filter() == JVMTI_HEAP_OBJECT_UNTAGGED) return;
1214 } else {
1215 if (object_filter() == JVMTI_HEAP_OBJECT_TAGGED) return;
1216 }
1217
1218 // invoke the agent's callback
1219 jvmtiIterationControl control = (*object_callback())(wrapper.klass_tag(),
1220 wrapper.obj_size(),
1221 wrapper.obj_tag_p(),
1222 (void*)user_data());
1223 if (control == JVMTI_ITERATION_ABORT) {
1224 set_iteration_aborted(true);
1225 }
1226 }
1227
1239 int heap_filter() const { return _heap_filter; }
1240 const jvmtiHeapCallbacks* callbacks() const { return _callbacks; }
1241 Klass* klass() const { return _klass; }
1242 const void* user_data() const { return _user_data; }
1243
1244 // indicates if the iteration has been aborted
1245 bool _iteration_aborted;
1246 bool is_iteration_aborted() const { return _iteration_aborted; }
1247
1248 // used to check the visit control flags. If the abort flag is set
1249 // then we set the iteration aborted flag so that the iteration completes
1250 // without processing any further objects
1251 bool check_flags_for_abort(jint flags) {
1252 bool is_abort = (flags & JVMTI_VISIT_ABORT) != 0;
1253 if (is_abort) {
1254 _iteration_aborted = true;
1255 }
1256 return is_abort;
1257 }
1258
1259 void visit_object(const JvmtiHeapwalkObject& obj);
1260 void visit_flat_fields(const JvmtiHeapwalkObject& obj);
1261 void visit_flat_array_elements(const JvmtiHeapwalkObject& obj);
1262
1263 public:
1264 IterateThroughHeapObjectClosure(JvmtiTagMap* tag_map,
1265 Klass* klass,
1266 int heap_filter,
1267 const jvmtiHeapCallbacks* heap_callbacks,
1268 const void* user_data) :
1269 _tag_map(tag_map),
1270 _klass(klass),
1271 _heap_filter(heap_filter),
1272 _callbacks(heap_callbacks),
1273 _user_data(user_data),
1274 _iteration_aborted(false)
1275 {
1276 }
1277
1278 void do_object(oop obj);
1279 };
1280
1281 // invoked for each object in the heap
1282 void IterateThroughHeapObjectClosure::do_object(oop obj) {
1283 assert(obj != nullptr, "Heap iteration should never produce null!");
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 if (LayoutKindHelper::is_nullable_flat(field->layout_kind())) {
1403 address payload = cast_from_oop<address>(obj.obj()) + field_offset;
1404 if (field->inline_klass()->is_payload_marked_as_null(payload)) {
1405 continue;
1406 }
1407 }
1408 JvmtiHeapwalkObject field_obj(obj.obj(), field_offset, field->inline_klass(), field->layout_kind());
1409
1410 visit_object(field_obj);
1411
1412 // check if iteration has been halted
1413 if (is_iteration_aborted()) {
1414 return;
1415 }
1416 }
1417 }
1418
1419 void IterateThroughHeapObjectClosure::visit_flat_array_elements(const JvmtiHeapwalkObject& obj) {
1420 assert(!obj.is_flat() && obj.obj()->is_flatArray() , "sanity check");
1421 flatArrayOop array = flatArrayOop(obj.obj());
1422 FlatArrayKlass* faklass = FlatArrayKlass::cast(array->klass());
1423 InlineKlass* vk = InlineKlass::cast(faklass->element_klass());
1424 bool need_null_check = LayoutKindHelper::is_nullable_flat(faklass->layout_kind());
1425
1426 for (int index = 0; index < array->length(); index++) {
1427 address addr = (address)array->value_at_addr(index, faklass->layout_helper());
1428 // check for null
1429 if (need_null_check) {
1430 if (vk->is_payload_marked_as_null(addr)) {
1431 continue;
1432 }
1433 }
1434
1435 // offset in the array oop
1436 int offset = (int)(addr - cast_from_oop<address>(array));
1437 JvmtiHeapwalkObject elem(obj.obj(), offset, vk, faklass->layout_kind());
1438
1439 visit_object(elem);
1440
1441 // check if iteration has been halted
1442 if (is_iteration_aborted()) {
1443 return;
1444 }
1445 }
1446 }
1447
1448 // Deprecated function to iterate over all objects in the heap
1449 void JvmtiTagMap::iterate_over_heap(jvmtiHeapObjectFilter object_filter,
1450 Klass* klass,
1451 jvmtiHeapObjectCallback heap_object_callback,
1452 const void* user_data)
1453 {
1454 // EA based optimizations on tagged objects are already reverted.
1455 EscapeBarrier eb(object_filter == JVMTI_HEAP_OBJECT_UNTAGGED ||
1456 object_filter == JVMTI_HEAP_OBJECT_EITHER,
1457 JavaThread::current());
1458 eb.deoptimize_objects_all_threads();
1459 Arena dead_object_arena(mtServiceability);
1460 GrowableArray <jlong> dead_objects(&dead_object_arena, 10, 0, 0);
1461 {
1462 MutexLocker ml(Heap_lock);
1463 IterateOverHeapObjectClosure blk(this,
1464 klass,
1465 object_filter,
1466 heap_object_callback,
1467 user_data);
1468 VM_HeapIterateOperation op(&blk, &dead_objects);
1469 VMThread::execute(&op);
1470 }
1471 convert_flat_object_entries();
1472
1473 // Post events outside of Heap_lock
1474 post_dead_objects(&dead_objects);
1475 }
1476
1477
1478 // Iterates over all objects in the heap
1479 void JvmtiTagMap::iterate_through_heap(jint heap_filter,
1480 Klass* klass,
1481 const jvmtiHeapCallbacks* callbacks,
1482 const void* user_data)
1483 {
1484 // EA based optimizations on tagged objects are already reverted.
1485 EscapeBarrier eb(!(heap_filter & JVMTI_HEAP_FILTER_UNTAGGED), JavaThread::current());
1486 eb.deoptimize_objects_all_threads();
1487
1488 Arena dead_object_arena(mtServiceability);
1489 GrowableArray<jlong> dead_objects(&dead_object_arena, 10, 0, 0);
1490 {
1491 MutexLocker ml(Heap_lock);
1492 IterateThroughHeapObjectClosure blk(this,
1493 klass,
1494 heap_filter,
1495 callbacks,
1496 user_data);
1497 VM_HeapIterateOperation op(&blk, &dead_objects);
1498 VMThread::execute(&op);
1499 }
1500 convert_flat_object_entries();
1501
1502 // Post events outside of Heap_lock
1503 post_dead_objects(&dead_objects);
1504 }
1505
1506 void JvmtiTagMap::remove_dead_entries_locked(GrowableArray<jlong>* objects) {
1507 assert(is_locked(), "precondition");
1508 if (_needs_cleaning) {
1509 // Recheck whether to post object free events under the lock.
1510 if (!env()->is_enabled(JVMTI_EVENT_OBJECT_FREE)) {
1511 objects = nullptr;
1512 }
1513 log_info(jvmti, table)("TagMap table needs cleaning%s",
1514 ((objects != nullptr) ? " and posting" : ""));
1515 _hashmap->remove_dead_entries(objects);
1516 _needs_cleaning = false;
1517 }
1518 }
1519
1520 void JvmtiTagMap::remove_dead_entries(GrowableArray<jlong>* objects) {
1521 MutexLocker ml(lock(), Mutex::_no_safepoint_check_flag);
1522 remove_dead_entries_locked(objects);
1523 }
1524
1525 void JvmtiTagMap::post_dead_objects(GrowableArray<jlong>* const objects) {
1526 assert(Thread::current()->is_Java_thread(), "Must post from JavaThread");
1527 if (objects != nullptr && objects->length() > 0) {
1528 JvmtiExport::post_object_free(env(), objects);
1529 log_info(jvmti, table)("%d free object posted", objects->length());
1530 }
1531 }
1532
1533 void JvmtiTagMap::remove_and_post_dead_objects() {
1534 ResourceMark rm;
1535 GrowableArray<jlong> objects;
1650 if (error != JVMTI_ERROR_NONE) {
1651 if (object_result_ptr != nullptr) {
1652 _env->Deallocate((unsigned char*)object_result_ptr);
1653 }
1654 return error;
1655 }
1656 for (int i=0; i<count; i++) {
1657 (*tag_result_ptr)[i] = (jlong)_tag_results->at(i);
1658 }
1659 }
1660
1661 *count_ptr = count;
1662 return JVMTI_ERROR_NONE;
1663 }
1664 };
1665
1666 // return the list of objects with the specified tags
1667 jvmtiError JvmtiTagMap::get_objects_with_tags(const jlong* tags,
1668 jint count, jint* count_ptr, jobject** object_result_ptr, jlong** tag_result_ptr) {
1669
1670 // ensure flat object conversion is completed
1671 convert_flat_object_entries();
1672
1673 TagObjectCollector collector(env(), tags, count);
1674 {
1675 // iterate over all tagged objects
1676 MutexLocker ml(lock(), Mutex::_no_safepoint_check_flag);
1677 // Can't post ObjectFree events here from a JavaThread, so this
1678 // will race with the gc_notification thread in the tiny
1679 // window where the object is not marked but hasn't been notified that
1680 // it is collected yet.
1681 _hashmap->entry_iterate(&collector);
1682 }
1683 return collector.result(count_ptr, object_result_ptr, tag_result_ptr);
1684 }
1685
1686 // helper to map a jvmtiHeapReferenceKind to an old style jvmtiHeapRootKind
1687 // (not performance critical as only used for roots)
1688 static jvmtiHeapRootKind toJvmtiHeapRootKind(jvmtiHeapReferenceKind kind) {
1689 switch (kind) {
1690 case JVMTI_HEAP_REFERENCE_JNI_GLOBAL: return JVMTI_HEAP_ROOT_JNI_GLOBAL;
1691 case JVMTI_HEAP_REFERENCE_SYSTEM_CLASS: return JVMTI_HEAP_ROOT_SYSTEM_CLASS;
1692 case JVMTI_HEAP_REFERENCE_STACK_LOCAL: return JVMTI_HEAP_ROOT_STACK_LOCAL;
1693 case JVMTI_HEAP_REFERENCE_JNI_LOCAL: return JVMTI_HEAP_ROOT_JNI_LOCAL;
1694 case JVMTI_HEAP_REFERENCE_THREAD: return JVMTI_HEAP_ROOT_THREAD;
1695 case JVMTI_HEAP_REFERENCE_OTHER: return JVMTI_HEAP_ROOT_OTHER;
1696 default: ShouldNotReachHere(); return JVMTI_HEAP_ROOT_OTHER;
1697 }
1698 }
1699
1700 // Base class for all heap walk contexts. The base class maintains a flag
1701 // to indicate if the context is valid or not.
1702 class HeapWalkContext {
1703 private:
1704 bool _valid;
1705 public:
1706 HeapWalkContext(bool valid) { _valid = valid; }
1707 void invalidate() { _valid = false; }
1708 bool is_valid() const { return _valid; }
1709 };
1710
1711 // A basic heap walk context for the deprecated heap walking functions.
1712 // The context for a basic heap walk are the callbacks and fields used by
1713 // the referrer caching scheme.
1714 class BasicHeapWalkContext: public HeapWalkContext {
1715 private:
1716 jvmtiHeapRootCallback _heap_root_callback;
1717 jvmtiStackReferenceCallback _stack_ref_callback;
1718 jvmtiObjectReferenceCallback _object_ref_callback;
1719
1720 // used for caching
1721 JvmtiHeapwalkObject _last_referrer;
1722 jlong _last_referrer_tag;
1723
1724 public:
1725 BasicHeapWalkContext() : HeapWalkContext(false) { }
1726
1727 BasicHeapWalkContext(jvmtiHeapRootCallback heap_root_callback,
1728 jvmtiStackReferenceCallback stack_ref_callback,
1729 jvmtiObjectReferenceCallback object_ref_callback) :
1730 HeapWalkContext(true),
1731 _heap_root_callback(heap_root_callback),
1732 _stack_ref_callback(stack_ref_callback),
1733 _object_ref_callback(object_ref_callback),
1734 _last_referrer(),
1735 _last_referrer_tag(0) {
1736 }
1737
1738 // accessors
1739 jvmtiHeapRootCallback heap_root_callback() const { return _heap_root_callback; }
1740 jvmtiStackReferenceCallback stack_ref_callback() const { return _stack_ref_callback; }
1741 jvmtiObjectReferenceCallback object_ref_callback() const { return _object_ref_callback; }
1742
1743 JvmtiHeapwalkObject last_referrer() const { return _last_referrer; }
1744 void set_last_referrer(const JvmtiHeapwalkObject& referrer) { _last_referrer = referrer; }
1745 jlong last_referrer_tag() const { return _last_referrer_tag; }
1746 void set_last_referrer_tag(jlong value) { _last_referrer_tag = value; }
1747 };
1748
1749 // The advanced heap walk context for the FollowReferences functions.
1750 // The context is the callbacks, and the fields used for filtering.
1751 class AdvancedHeapWalkContext: public HeapWalkContext {
1752 private:
1753 jint _heap_filter;
1754 Klass* _klass_filter;
1755 const jvmtiHeapCallbacks* _heap_callbacks;
1756
1757 public:
1758 AdvancedHeapWalkContext() : HeapWalkContext(false) { }
1759
1760 AdvancedHeapWalkContext(jint heap_filter,
1761 Klass* klass_filter,
1762 const jvmtiHeapCallbacks* heap_callbacks) :
1763 HeapWalkContext(true),
1764 _heap_filter(heap_filter),
1797 static bool is_basic_heap_walk() { return _heap_walk_type == basic; }
1798 static bool is_advanced_heap_walk() { return _heap_walk_type == advanced; }
1799
1800 // context for basic style heap walk
1801 static BasicHeapWalkContext _basic_context;
1802 static BasicHeapWalkContext* basic_context() {
1803 assert(_basic_context.is_valid(), "invalid");
1804 return &_basic_context;
1805 }
1806
1807 // context for advanced style heap walk
1808 static AdvancedHeapWalkContext _advanced_context;
1809 static AdvancedHeapWalkContext* advanced_context() {
1810 assert(_advanced_context.is_valid(), "invalid");
1811 return &_advanced_context;
1812 }
1813
1814 // context needed for all heap walks
1815 static JvmtiTagMap* _tag_map;
1816 static const void* _user_data;
1817 static JvmtiHeapwalkVisitStack* _visit_stack;
1818
1819 // accessors
1820 static JvmtiTagMap* tag_map() { return _tag_map; }
1821 static const void* user_data() { return _user_data; }
1822 static JvmtiHeapwalkVisitStack* visit_stack() { return _visit_stack; }
1823
1824 // if the object hasn't been visited then push it onto the visit stack
1825 // so that it will be visited later
1826 static inline bool check_for_visit(const JvmtiHeapwalkObject&obj) {
1827 visit_stack()->check_for_visit(obj);
1828 return true;
1829 }
1830
1831 // return element count if the obj is array, -1 otherwise
1832 static jint get_array_length(const JvmtiHeapwalkObject& obj) {
1833 if (!obj.klass()->is_array_klass()) {
1834 return -1;
1835 }
1836 assert(!obj.is_flat(), "array cannot be flat");
1837 return (jint)arrayOop(obj.obj())->length();
1838 }
1839
1840
1841 // invoke basic style callbacks
1842 static inline bool invoke_basic_heap_root_callback
1843 (jvmtiHeapRootKind root_kind, const JvmtiHeapwalkObject& obj);
1844 static inline bool invoke_basic_stack_ref_callback
1845 (jvmtiHeapRootKind root_kind, jlong thread_tag, jint depth, jmethodID method,
1846 int slot, const JvmtiHeapwalkObject& obj);
1847 static inline bool invoke_basic_object_reference_callback
1848 (jvmtiObjectReferenceKind ref_kind, const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree, jint index);
1849
1850 // invoke advanced style callbacks
1851 static inline bool invoke_advanced_heap_root_callback
1852 (jvmtiHeapReferenceKind ref_kind, const JvmtiHeapwalkObject& obj);
1853 static inline bool invoke_advanced_stack_ref_callback
1854 (jvmtiHeapReferenceKind ref_kind, jlong thread_tag, jlong tid, int depth,
1855 jmethodID method, jlocation bci, jint slot, const JvmtiHeapwalkObject& obj);
1856 static inline bool invoke_advanced_object_reference_callback
1857 (jvmtiHeapReferenceKind ref_kind, const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree, jint index);
1858
1859 // used to report the value of primitive fields
1860 static inline bool report_primitive_field
1861 (jvmtiHeapReferenceKind ref_kind, const JvmtiHeapwalkObject& obj, jint index, address addr, char type);
1862
1863 public:
1864 // initialize for basic mode
1865 static void initialize_for_basic_heap_walk(JvmtiTagMap* tag_map,
1866 const void* user_data,
1867 BasicHeapWalkContext context,
1868 JvmtiHeapwalkVisitStack* visit_stack);
1869
1870 // initialize for advanced mode
1871 static void initialize_for_advanced_heap_walk(JvmtiTagMap* tag_map,
1872 const void* user_data,
1873 AdvancedHeapWalkContext context,
1874 JvmtiHeapwalkVisitStack* visit_stack);
1875
1876 // functions to report roots
1877 static inline bool report_simple_root(jvmtiHeapReferenceKind kind, const JvmtiHeapwalkObject& o);
1878 static inline bool report_jni_local_root(jlong thread_tag, jlong tid, jint depth,
1879 jmethodID m, const JvmtiHeapwalkObject& o);
1880 static inline bool report_stack_ref_root(jlong thread_tag, jlong tid, jint depth,
1881 jmethodID method, jlocation bci, jint slot, const JvmtiHeapwalkObject& o);
1882
1883 // functions to report references
1884 static inline bool report_array_element_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree, jint index);
1885 static inline bool report_class_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree);
1886 static inline bool report_class_loader_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree);
1887 static inline bool report_signers_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree);
1888 static inline bool report_protection_domain_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree);
1889 static inline bool report_superclass_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree);
1890 static inline bool report_interface_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree);
1891 static inline bool report_static_field_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree, jint slot);
1892 static inline bool report_field_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree, jint slot);
1893 static inline bool report_constant_pool_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree, jint index);
1894 static inline bool report_primitive_array_values(const JvmtiHeapwalkObject& array);
1895 static inline bool report_string_value(const JvmtiHeapwalkObject& str);
1896 static inline bool report_primitive_instance_field(const JvmtiHeapwalkObject& o, jint index, address value, char type);
1897 static inline bool report_primitive_static_field(const JvmtiHeapwalkObject& o, jint index, address value, char type);
1898 };
1899
1900 // statics
1901 int CallbackInvoker::_heap_walk_type;
1902 BasicHeapWalkContext CallbackInvoker::_basic_context;
1903 AdvancedHeapWalkContext CallbackInvoker::_advanced_context;
1904 JvmtiTagMap* CallbackInvoker::_tag_map;
1905 const void* CallbackInvoker::_user_data;
1906 JvmtiHeapwalkVisitStack* CallbackInvoker::_visit_stack;
1907
1908 // initialize for basic heap walk (IterateOverReachableObjects et al)
1909 void CallbackInvoker::initialize_for_basic_heap_walk(JvmtiTagMap* tag_map,
1910 const void* user_data,
1911 BasicHeapWalkContext context,
1912 JvmtiHeapwalkVisitStack* visit_stack) {
1913 _tag_map = tag_map;
1914 _user_data = user_data;
1915 _basic_context = context;
1916 _advanced_context.invalidate(); // will trigger assertion if used
1917 _heap_walk_type = basic;
1918 _visit_stack = visit_stack;
1919 }
1920
1921 // initialize for advanced heap walk (FollowReferences)
1922 void CallbackInvoker::initialize_for_advanced_heap_walk(JvmtiTagMap* tag_map,
1923 const void* user_data,
1924 AdvancedHeapWalkContext context,
1925 JvmtiHeapwalkVisitStack* visit_stack) {
1926 _tag_map = tag_map;
1927 _user_data = user_data;
1928 _advanced_context = context;
1929 _basic_context.invalidate(); // will trigger assertion if used
1930 _heap_walk_type = advanced;
1931 _visit_stack = visit_stack;
1932 }
1933
1934
1935 // invoke basic style heap root callback
1936 inline bool CallbackInvoker::invoke_basic_heap_root_callback(jvmtiHeapRootKind root_kind, const JvmtiHeapwalkObject& obj) {
1937 // if we heap roots should be reported
1938 jvmtiHeapRootCallback cb = basic_context()->heap_root_callback();
1939 if (cb == nullptr) {
1940 return check_for_visit(obj);
1941 }
1942
1943 CallbackWrapper wrapper(tag_map(), obj);
1944 jvmtiIterationControl control = (*cb)(root_kind,
1945 wrapper.klass_tag(),
1946 wrapper.obj_size(),
1947 wrapper.obj_tag_p(),
1948 (void*)user_data());
1949 // push root to visit stack when following references
1950 if (control == JVMTI_ITERATION_CONTINUE &&
1951 basic_context()->object_ref_callback() != nullptr) {
1952 visit_stack()->push(obj);
1953 }
1954 return control != JVMTI_ITERATION_ABORT;
1955 }
1956
1957 // invoke basic style stack ref callback
1958 inline bool CallbackInvoker::invoke_basic_stack_ref_callback(jvmtiHeapRootKind root_kind,
1959 jlong thread_tag,
1960 jint depth,
1961 jmethodID method,
1962 int slot,
1963 const JvmtiHeapwalkObject& obj) {
1964 // if we stack refs should be reported
1965 jvmtiStackReferenceCallback cb = basic_context()->stack_ref_callback();
1966 if (cb == nullptr) {
1967 return check_for_visit(obj);
1968 }
1969
1970 CallbackWrapper wrapper(tag_map(), obj);
1971 jvmtiIterationControl control = (*cb)(root_kind,
1972 wrapper.klass_tag(),
1973 wrapper.obj_size(),
1974 wrapper.obj_tag_p(),
1975 thread_tag,
1976 depth,
1977 method,
1978 slot,
1979 (void*)user_data());
1980 // push root to visit stack when following references
1981 if (control == JVMTI_ITERATION_CONTINUE &&
1982 basic_context()->object_ref_callback() != nullptr) {
1983 visit_stack()->push(obj);
1984 }
1985 return control != JVMTI_ITERATION_ABORT;
1986 }
1987
1988 // invoke basic style object reference callback
1989 inline bool CallbackInvoker::invoke_basic_object_reference_callback(jvmtiObjectReferenceKind ref_kind,
1990 const JvmtiHeapwalkObject& referrer,
1991 const JvmtiHeapwalkObject& referree,
1992 jint index) {
1993
1994 BasicHeapWalkContext* context = basic_context();
1995
1996 // callback requires the referrer's tag. If it's the same referrer
1997 // as the last call then we use the cached value.
1998 jlong referrer_tag;
1999 if (referrer == context->last_referrer()) {
2000 referrer_tag = context->last_referrer_tag();
2001 } else {
2002 referrer_tag = tag_map()->find(referrer);
2003 }
2004
2005 // do the callback
2006 CallbackWrapper wrapper(tag_map(), referree);
2007 jvmtiObjectReferenceCallback cb = context->object_ref_callback();
2008 jvmtiIterationControl control = (*cb)(ref_kind,
2009 wrapper.klass_tag(),
2010 wrapper.obj_size(),
2011 wrapper.obj_tag_p(),
2012 referrer_tag,
2013 index,
2014 (void*)user_data());
2015
2016 // record referrer and referrer tag. For self-references record the
2017 // tag value from the callback as this might differ from referrer_tag.
2018 context->set_last_referrer(referrer);
2019 if (referrer == referree) {
2020 context->set_last_referrer_tag(*wrapper.obj_tag_p());
2021 } else {
2022 context->set_last_referrer_tag(referrer_tag);
2023 }
2024
2025 if (control == JVMTI_ITERATION_CONTINUE) {
2026 return check_for_visit(referree);
2027 } else {
2028 return control != JVMTI_ITERATION_ABORT;
2029 }
2030 }
2031
2032 // invoke advanced style heap root callback
2033 inline bool CallbackInvoker::invoke_advanced_heap_root_callback(jvmtiHeapReferenceKind ref_kind,
2034 const JvmtiHeapwalkObject& obj) {
2035 AdvancedHeapWalkContext* context = advanced_context();
2036
2037 // check that callback is provided
2038 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
2039 if (cb == nullptr) {
2040 return check_for_visit(obj);
2041 }
2042
2043 // apply class filter
2044 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2045 return check_for_visit(obj);
2046 }
2047
2048 // setup the callback wrapper
2049 CallbackWrapper wrapper(tag_map(), obj);
2050
2051 // apply tag filter
2052 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2053 wrapper.klass_tag(),
2054 context->heap_filter())) {
2055 return check_for_visit(obj);
2056 }
2057
2058 // for arrays we need the length, otherwise -1
2059 jint len = get_array_length(obj);
2060
2061 // invoke the callback
2062 jint res = (*cb)(ref_kind,
2063 nullptr, // referrer info
2064 wrapper.klass_tag(),
2065 0, // referrer_class_tag is 0 for heap root
2066 wrapper.obj_size(),
2067 wrapper.obj_tag_p(),
2068 nullptr, // referrer_tag_p
2069 len,
2070 (void*)user_data());
2071 if (res & JVMTI_VISIT_ABORT) {
2072 return false;// referrer class tag
2073 }
2074 if (res & JVMTI_VISIT_OBJECTS) {
2075 check_for_visit(obj);
2076 }
2077 return true;
2078 }
2079
2080 // report a reference from a thread stack to an object
2081 inline bool CallbackInvoker::invoke_advanced_stack_ref_callback(jvmtiHeapReferenceKind ref_kind,
2082 jlong thread_tag,
2083 jlong tid,
2084 int depth,
2085 jmethodID method,
2086 jlocation bci,
2087 jint slot,
2088 const JvmtiHeapwalkObject& obj) {
2089 AdvancedHeapWalkContext* context = advanced_context();
2090
2091 // check that callback is provider
2092 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
2093 if (cb == nullptr) {
2094 return check_for_visit(obj);
2095 }
2096
2097 // apply class filter
2098 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2099 return check_for_visit(obj);
2100 }
2101
2102 // setup the callback wrapper
2103 CallbackWrapper wrapper(tag_map(), obj);
2104
2105 // apply tag filter
2106 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2107 wrapper.klass_tag(),
2108 context->heap_filter())) {
2109 return check_for_visit(obj);
2110 }
2111
2112 // setup the referrer info
2113 jvmtiHeapReferenceInfo reference_info;
2114 reference_info.stack_local.thread_tag = thread_tag;
2115 reference_info.stack_local.thread_id = tid;
2116 reference_info.stack_local.depth = depth;
2117 reference_info.stack_local.method = method;
2118 reference_info.stack_local.location = bci;
2119 reference_info.stack_local.slot = slot;
2120
2121 // for arrays we need the length, otherwise -1
2122 jint len = get_array_length(obj);
2123
2124 // call into the agent
2125 int res = (*cb)(ref_kind,
2126 &reference_info,
2127 wrapper.klass_tag(),
2128 0, // referrer_class_tag is 0 for heap root (stack)
2129 wrapper.obj_size(),
2130 wrapper.obj_tag_p(),
2131 nullptr, // referrer_tag is 0 for root
2132 len,
2133 (void*)user_data());
2134
2135 if (res & JVMTI_VISIT_ABORT) {
2136 return false;
2137 }
2138 if (res & JVMTI_VISIT_OBJECTS) {
2139 check_for_visit(obj);
2140 }
2141 return true;
2142 }
2143
2144 // This mask is used to pass reference_info to a jvmtiHeapReferenceCallback
2145 // only for ref_kinds defined by the JVM TI spec. Otherwise, null is passed.
2146 #define REF_INFO_MASK ((1 << JVMTI_HEAP_REFERENCE_FIELD) \
2147 | (1 << JVMTI_HEAP_REFERENCE_STATIC_FIELD) \
2148 | (1 << JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT) \
2149 | (1 << JVMTI_HEAP_REFERENCE_CONSTANT_POOL) \
2150 | (1 << JVMTI_HEAP_REFERENCE_STACK_LOCAL) \
2151 | (1 << JVMTI_HEAP_REFERENCE_JNI_LOCAL))
2152
2153 // invoke the object reference callback to report a reference
2154 inline bool CallbackInvoker::invoke_advanced_object_reference_callback(jvmtiHeapReferenceKind ref_kind,
2155 const JvmtiHeapwalkObject& referrer,
2156 const JvmtiHeapwalkObject& obj,
2157 jint index)
2158 {
2159 // field index is only valid field in reference_info
2160 static jvmtiHeapReferenceInfo reference_info = { 0 };
2161
2162 AdvancedHeapWalkContext* context = advanced_context();
2163
2164 // check that callback is provider
2165 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
2166 if (cb == nullptr) {
2167 return check_for_visit(obj);
2168 }
2169
2170 // apply class filter
2171 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2172 return check_for_visit(obj);
2173 }
2174
2175 // setup the callback wrapper
2176 TwoOopCallbackWrapper wrapper(tag_map(), referrer, obj);
2177
2178 // apply tag filter
2179 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2180 wrapper.klass_tag(),
2181 context->heap_filter())) {
2182 return check_for_visit(obj);
2183 }
2184
2185 // field index is only valid field in reference_info
2186 reference_info.field.index = index;
2187
2188 // for arrays we need the length, otherwise -1
2189 jint len = get_array_length(obj);
2190
2191 // invoke the callback
2192 int res = (*cb)(ref_kind,
2193 (REF_INFO_MASK & (1 << ref_kind)) ? &reference_info : nullptr,
2194 wrapper.klass_tag(),
2195 wrapper.referrer_klass_tag(),
2196 wrapper.obj_size(),
2197 wrapper.obj_tag_p(),
2198 wrapper.referrer_tag_p(),
2199 len,
2200 (void*)user_data());
2201
2202 if (res & JVMTI_VISIT_ABORT) {
2203 return false;
2204 }
2205 if (res & JVMTI_VISIT_OBJECTS) {
2206 check_for_visit(obj);
2207 }
2208 return true;
2209 }
2210
2211 // report a "simple root"
2212 inline bool CallbackInvoker::report_simple_root(jvmtiHeapReferenceKind kind, const JvmtiHeapwalkObject& obj) {
2213 assert(kind != JVMTI_HEAP_REFERENCE_STACK_LOCAL &&
2214 kind != JVMTI_HEAP_REFERENCE_JNI_LOCAL, "not a simple root");
2215
2216 if (is_basic_heap_walk()) {
2217 // map to old style root kind
2218 jvmtiHeapRootKind root_kind = toJvmtiHeapRootKind(kind);
2219 return invoke_basic_heap_root_callback(root_kind, obj);
2220 } else {
2221 assert(is_advanced_heap_walk(), "wrong heap walk type");
2222 return invoke_advanced_heap_root_callback(kind, obj);
2223 }
2224 }
2225
2226
2227 // invoke the primitive array values
2228 inline bool CallbackInvoker::report_primitive_array_values(const JvmtiHeapwalkObject& obj) {
2229 assert(obj.klass()->is_typeArray_klass(), "not a primitive array");
2230
2231 AdvancedHeapWalkContext* context = advanced_context();
2232 assert(context->array_primitive_value_callback() != nullptr, "no callback");
2233
2234 // apply class filter
2235 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2236 return true;
2237 }
2238
2239 CallbackWrapper wrapper(tag_map(), obj);
2240
2241 // apply tag filter
2242 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2243 wrapper.klass_tag(),
2244 context->heap_filter())) {
2245 return true;
2246 }
2247
2248 // invoke the callback
2249 int res = invoke_array_primitive_value_callback(context->array_primitive_value_callback(),
2250 &wrapper,
2251 obj,
2252 (void*)user_data());
2253 return (!(res & JVMTI_VISIT_ABORT));
2254 }
2255
2256 // invoke the string value callback
2257 inline bool CallbackInvoker::report_string_value(const JvmtiHeapwalkObject& str) {
2258 assert(str.klass() == vmClasses::String_klass(), "not a string");
2259
2260 AdvancedHeapWalkContext* context = advanced_context();
2261 assert(context->string_primitive_value_callback() != nullptr, "no callback");
2262
2263 // apply class filter
2264 if (is_filtered_by_klass_filter(str, context->klass_filter())) {
2265 return true;
2266 }
2267
2268 CallbackWrapper wrapper(tag_map(), str);
2269
2270 // apply tag filter
2271 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2272 wrapper.klass_tag(),
2273 context->heap_filter())) {
2274 return true;
2275 }
2276
2277 // invoke the callback
2278 int res = invoke_string_value_callback(context->string_primitive_value_callback(),
2279 &wrapper,
2280 str,
2281 (void*)user_data());
2282 return (!(res & JVMTI_VISIT_ABORT));
2283 }
2284
2285 // invoke the primitive field callback
2286 inline bool CallbackInvoker::report_primitive_field(jvmtiHeapReferenceKind ref_kind,
2287 const JvmtiHeapwalkObject& obj,
2288 jint index,
2289 address addr,
2290 char type)
2291 {
2292 // for primitive fields only the index will be set
2293 static jvmtiHeapReferenceInfo reference_info = { 0 };
2294
2295 AdvancedHeapWalkContext* context = advanced_context();
2296 assert(context->primitive_field_callback() != nullptr, "no callback");
2297
2298 // apply class filter
2299 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2300 return true;
2301 }
2302
2303 CallbackWrapper wrapper(tag_map(), obj);
2304
2305 // apply tag filter
2306 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2307 wrapper.klass_tag(),
2315 // map the type
2316 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
2317
2318 // setup the jvalue
2319 jvalue value;
2320 copy_to_jvalue(&value, addr, value_type);
2321
2322 jvmtiPrimitiveFieldCallback cb = context->primitive_field_callback();
2323 int res = (*cb)(ref_kind,
2324 &reference_info,
2325 wrapper.klass_tag(),
2326 wrapper.obj_tag_p(),
2327 value,
2328 value_type,
2329 (void*)user_data());
2330 return (!(res & JVMTI_VISIT_ABORT));
2331 }
2332
2333
2334 // instance field
2335 inline bool CallbackInvoker::report_primitive_instance_field(const JvmtiHeapwalkObject& obj,
2336 jint index,
2337 address value,
2338 char type) {
2339 return report_primitive_field(JVMTI_HEAP_REFERENCE_FIELD,
2340 obj,
2341 index,
2342 value,
2343 type);
2344 }
2345
2346 // static field
2347 inline bool CallbackInvoker::report_primitive_static_field(const JvmtiHeapwalkObject& obj,
2348 jint index,
2349 address value,
2350 char type) {
2351 return report_primitive_field(JVMTI_HEAP_REFERENCE_STATIC_FIELD,
2352 obj,
2353 index,
2354 value,
2355 type);
2356 }
2357
2358 // report a JNI local (root object) to the profiler
2359 inline bool CallbackInvoker::report_jni_local_root(jlong thread_tag, jlong tid, jint depth, jmethodID m, const JvmtiHeapwalkObject& obj) {
2360 if (is_basic_heap_walk()) {
2361 return invoke_basic_stack_ref_callback(JVMTI_HEAP_ROOT_JNI_LOCAL,
2362 thread_tag,
2363 depth,
2364 m,
2365 -1,
2366 obj);
2367 } else {
2368 return invoke_advanced_stack_ref_callback(JVMTI_HEAP_REFERENCE_JNI_LOCAL,
2369 thread_tag, tid,
2370 depth,
2371 m,
2372 (jlocation)-1,
2373 -1,
2374 obj);
2375 }
2376 }
2377
2378
2379 // report a local (stack reference, root object)
2380 inline bool CallbackInvoker::report_stack_ref_root(jlong thread_tag,
2381 jlong tid,
2382 jint depth,
2383 jmethodID method,
2384 jlocation bci,
2385 jint slot,
2386 const JvmtiHeapwalkObject& obj) {
2387 if (is_basic_heap_walk()) {
2388 return invoke_basic_stack_ref_callback(JVMTI_HEAP_ROOT_STACK_LOCAL,
2389 thread_tag,
2390 depth,
2391 method,
2392 slot,
2393 obj);
2394 } else {
2395 return invoke_advanced_stack_ref_callback(JVMTI_HEAP_REFERENCE_STACK_LOCAL,
2396 thread_tag,
2397 tid,
2398 depth,
2399 method,
2400 bci,
2401 slot,
2402 obj);
2403 }
2404 }
2405
2406 // report an object referencing a class.
2407 inline bool CallbackInvoker::report_class_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree) {
2408 if (is_basic_heap_walk()) {
2409 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS, referrer, referree, -1);
2410 } else {
2411 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CLASS, referrer, referree, -1);
2412 }
2413 }
2414
2415 // report a class referencing its class loader.
2416 inline bool CallbackInvoker::report_class_loader_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree) {
2417 if (is_basic_heap_walk()) {
2418 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS_LOADER, referrer, referree, -1);
2419 } else {
2420 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CLASS_LOADER, referrer, referree, -1);
2421 }
2422 }
2423
2424 // report a class referencing its signers.
2425 inline bool CallbackInvoker::report_signers_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree) {
2426 if (is_basic_heap_walk()) {
2427 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_SIGNERS, referrer, referree, -1);
2428 } else {
2429 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_SIGNERS, referrer, referree, -1);
2430 }
2431 }
2432
2433 // report a class referencing its protection domain..
2434 inline bool CallbackInvoker::report_protection_domain_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree) {
2435 if (is_basic_heap_walk()) {
2436 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_PROTECTION_DOMAIN, referrer, referree, -1);
2437 } else {
2438 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_PROTECTION_DOMAIN, referrer, referree, -1);
2439 }
2440 }
2441
2442 // report a class referencing its superclass.
2443 inline bool CallbackInvoker::report_superclass_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree) {
2444 if (is_basic_heap_walk()) {
2445 // Send this to be consistent with past implementation
2446 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS, referrer, referree, -1);
2447 } else {
2448 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_SUPERCLASS, referrer, referree, -1);
2449 }
2450 }
2451
2452 // report a class referencing one of its interfaces.
2453 inline bool CallbackInvoker::report_interface_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree) {
2454 if (is_basic_heap_walk()) {
2455 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_INTERFACE, referrer, referree, -1);
2456 } else {
2457 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_INTERFACE, referrer, referree, -1);
2458 }
2459 }
2460
2461 // report a class referencing one of its static fields.
2462 inline bool CallbackInvoker::report_static_field_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree, jint slot) {
2463 if (is_basic_heap_walk()) {
2464 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_STATIC_FIELD, referrer, referree, slot);
2465 } else {
2466 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_STATIC_FIELD, referrer, referree, slot);
2467 }
2468 }
2469
2470 // report an array referencing an element object
2471 inline bool CallbackInvoker::report_array_element_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree, jint index) {
2472 if (is_basic_heap_walk()) {
2473 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_ARRAY_ELEMENT, referrer, referree, index);
2474 } else {
2475 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT, referrer, referree, index);
2476 }
2477 }
2478
2479 // report an object referencing an instance field object
2480 inline bool CallbackInvoker::report_field_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree, jint slot) {
2481 if (is_basic_heap_walk()) {
2482 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_FIELD, referrer, referree, slot);
2483 } else {
2484 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_FIELD, referrer, referree, slot);
2485 }
2486 }
2487
2488 // report an array referencing an element object
2489 inline bool CallbackInvoker::report_constant_pool_reference(const JvmtiHeapwalkObject& referrer, const JvmtiHeapwalkObject& referree, jint index) {
2490 if (is_basic_heap_walk()) {
2491 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CONSTANT_POOL, referrer, referree, index);
2492 } else {
2493 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CONSTANT_POOL, referrer, referree, index);
2494 }
2495 }
2496
2497 // A supporting closure used to process simple roots
2498 class SimpleRootsClosure : public OopClosure {
2499 private:
2500 jvmtiHeapReferenceKind _kind;
2501 bool _continue;
2502
2503 jvmtiHeapReferenceKind root_kind() { return _kind; }
2504
2505 public:
2506 void set_kind(jvmtiHeapReferenceKind kind) {
2507 _kind = kind;
2508 _continue = true;
2509 }
2629
2630 public:
2631 StackRefCollector(JvmtiTagMap* tag_map, JNILocalRootsClosure* blk, JavaThread* java_thread)
2632 : _tag_map(tag_map), _blk(blk), _java_thread(java_thread),
2633 _threadObj(nullptr), _thread_tag(0), _tid(0),
2634 _is_top_frame(true), _depth(0), _last_entry_frame(nullptr)
2635 {
2636 }
2637
2638 bool set_thread(oop o);
2639 // Sets the thread and reports the reference to it with the specified kind.
2640 bool set_thread(jvmtiHeapReferenceKind kind, oop o);
2641
2642 bool do_frame(vframe* vf);
2643 // Handles frames until vf->sender() is null.
2644 bool process_frames(vframe* vf);
2645 };
2646
2647 bool StackRefCollector::set_thread(oop o) {
2648 _threadObj = o;
2649 _thread_tag = _tag_map->find(_threadObj);
2650 _tid = java_lang_Thread::thread_id(_threadObj);
2651
2652 _is_top_frame = true;
2653 _depth = 0;
2654 _last_entry_frame = nullptr;
2655
2656 return true;
2657 }
2658
2659 bool StackRefCollector::set_thread(jvmtiHeapReferenceKind kind, oop o) {
2660 return set_thread(o)
2661 && CallbackInvoker::report_simple_root(kind, _threadObj);
2662 }
2663
2664 bool StackRefCollector::report_java_stack_refs(StackValueCollection* values, jmethodID method, jlocation bci, jint slot_offset) {
2665 for (int index = 0; index < values->size(); index++) {
2666 if (values->at(index)->type() == T_OBJECT) {
2667 oop obj = values->obj_at(index)();
2668 if (obj == nullptr) {
2669 continue;
2762 return true;
2763 }
2764
2765
2766 // A VM operation to iterate over objects that are reachable from
2767 // a set of roots or an initial object.
2768 //
2769 // For VM_HeapWalkOperation the set of roots used is :-
2770 //
2771 // - All JNI global references
2772 // - All inflated monitors
2773 // - All classes loaded by the boot class loader (or all classes
2774 // in the event that class unloading is disabled)
2775 // - All java threads
2776 // - For each java thread then all locals and JNI local references
2777 // on the thread's execution stack
2778 // - All visible/explainable objects from Universes::oops_do
2779 //
2780 class VM_HeapWalkOperation: public VM_Operation {
2781 private:
2782 bool _is_advanced_heap_walk; // indicates FollowReferences
2783 JvmtiTagMap* _tag_map;
2784 Handle _initial_object;
2785 JvmtiHeapwalkVisitStack _visit_stack;
2786
2787 // Dead object tags in JvmtiTagMap
2788 GrowableArray<jlong>* _dead_objects;
2789
2790 bool _following_object_refs; // are we following object references
2791
2792 bool _reporting_primitive_fields; // optional reporting
2793 bool _reporting_primitive_array_values;
2794 bool _reporting_string_values;
2795
2796 // accessors
2797 bool is_advanced_heap_walk() const { return _is_advanced_heap_walk; }
2798 JvmtiTagMap* tag_map() const { return _tag_map; }
2799 Handle initial_object() const { return _initial_object; }
2800
2801 bool is_following_references() const { return _following_object_refs; }
2802
2803 bool is_reporting_primitive_fields() const { return _reporting_primitive_fields; }
2804 bool is_reporting_primitive_array_values() const { return _reporting_primitive_array_values; }
2805 bool is_reporting_string_values() const { return _reporting_string_values; }
2806
2807 JvmtiHeapwalkVisitStack* visit_stack() { return &_visit_stack; }
2808
2809 // iterate over the various object types
2810 inline bool iterate_over_array(const JvmtiHeapwalkObject& o);
2811 inline bool iterate_over_flat_array(const JvmtiHeapwalkObject& o);
2812 inline bool iterate_over_type_array(const JvmtiHeapwalkObject& o);
2813 inline bool iterate_over_class(const JvmtiHeapwalkObject& o);
2814 inline bool iterate_over_object(const JvmtiHeapwalkObject& o);
2815
2816 // root collection
2817 inline bool collect_simple_roots();
2818 inline bool collect_stack_roots();
2819 inline bool collect_stack_refs(JavaThread* java_thread, JNILocalRootsClosure* blk);
2820 inline bool collect_vthread_stack_refs(oop vt);
2821
2822 // visit an object
2823 inline bool visit(const JvmtiHeapwalkObject& o);
2824
2825 public:
2826 VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2827 Handle initial_object,
2828 BasicHeapWalkContext callbacks,
2829 const void* user_data,
2830 GrowableArray<jlong>* objects);
2831
2832 VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2833 Handle initial_object,
2834 AdvancedHeapWalkContext callbacks,
2835 const void* user_data,
2836 GrowableArray<jlong>* objects);
2837
2838 ~VM_HeapWalkOperation();
2839
2840 VMOp_Type type() const { return VMOp_HeapWalkOperation; }
2841 void doit();
2842 };
2843
2844
2845 VM_HeapWalkOperation::VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2846 Handle initial_object,
2847 BasicHeapWalkContext callbacks,
2848 const void* user_data,
2849 GrowableArray<jlong>* objects) {
2850 _is_advanced_heap_walk = false;
2851 _tag_map = tag_map;
2852 _initial_object = initial_object;
2853 _following_object_refs = (callbacks.object_ref_callback() != nullptr);
2854 _reporting_primitive_fields = false;
2855 _reporting_primitive_array_values = false;
2856 _reporting_string_values = false;
2857 _dead_objects = objects;
2858 CallbackInvoker::initialize_for_basic_heap_walk(tag_map, user_data, callbacks, &_visit_stack);
2859 }
2860
2861 VM_HeapWalkOperation::VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2862 Handle initial_object,
2863 AdvancedHeapWalkContext callbacks,
2864 const void* user_data,
2865 GrowableArray<jlong>* objects) {
2866 _is_advanced_heap_walk = true;
2867 _tag_map = tag_map;
2868 _initial_object = initial_object;
2869 _following_object_refs = true;
2870 _reporting_primitive_fields = (callbacks.primitive_field_callback() != nullptr);;
2871 _reporting_primitive_array_values = (callbacks.array_primitive_value_callback() != nullptr);;
2872 _reporting_string_values = (callbacks.string_primitive_value_callback() != nullptr);;
2873 _dead_objects = objects;
2874 CallbackInvoker::initialize_for_advanced_heap_walk(tag_map, user_data, callbacks, &_visit_stack);
2875 }
2876
2877 VM_HeapWalkOperation::~VM_HeapWalkOperation() {
2878 }
2879
2880 // an array references its class and has a reference to
2881 // each element in the array
2882 inline bool VM_HeapWalkOperation::iterate_over_array(const JvmtiHeapwalkObject& o) {
2883 assert(!o.is_flat(), "Array object cannot be flattened");
2884 objArrayOop array = objArrayOop(o.obj());
2885
2886 // array reference to its class
2887 oop mirror = ObjArrayKlass::cast(array->klass())->java_mirror();
2888 if (!CallbackInvoker::report_class_reference(o, mirror)) {
2889 return false;
2890 }
2891
2892 // iterate over the array and report each reference to a
2893 // non-null element
2894 for (int index=0; index<array->length(); index++) {
2895 oop elem = array->obj_at(index);
2896 if (elem == nullptr) {
2897 continue;
2898 }
2899
2900 // report the array reference o[index] = elem
2901 if (!CallbackInvoker::report_array_element_reference(o, elem, index)) {
2902 return false;
2903 }
2904 }
2905 return true;
2906 }
2907
2908 // similar to iterate_over_array(), but itrates over flat array
2909 inline bool VM_HeapWalkOperation::iterate_over_flat_array(const JvmtiHeapwalkObject& o) {
2910 assert(!o.is_flat(), "Array object cannot be flattened");
2911 flatArrayOop array = flatArrayOop(o.obj());
2912 FlatArrayKlass* faklass = FlatArrayKlass::cast(array->klass());
2913 InlineKlass* vk = InlineKlass::cast(faklass->element_klass());
2914 bool need_null_check = LayoutKindHelper::is_nullable_flat(faklass->layout_kind());
2915
2916 // array reference to its class
2917 oop mirror = faklass->java_mirror();
2918 if (!CallbackInvoker::report_class_reference(o, mirror)) {
2919 return false;
2920 }
2921
2922 // iterate over the array and report each reference to a
2923 // non-null element
2924 for (int index = 0; index < array->length(); index++) {
2925 address addr = (address)array->value_at_addr(index, faklass->layout_helper());
2926
2927 // check for null
2928 if (need_null_check) {
2929 if (vk->is_payload_marked_as_null(addr)) {
2930 continue;
2931 }
2932 }
2933
2934 // offset in the array oop
2935 int offset = (int)(addr - cast_from_oop<address>(array));
2936 JvmtiHeapwalkObject elem(o.obj(), offset, vk, faklass->layout_kind());
2937
2938 // report the array reference
2939 if (!CallbackInvoker::report_array_element_reference(o, elem, index)) {
2940 return false;
2941 }
2942 }
2943 return true;
2944 }
2945
2946 // a type array references its class
2947 inline bool VM_HeapWalkOperation::iterate_over_type_array(const JvmtiHeapwalkObject& o) {
2948 assert(!o.is_flat(), "Array object cannot be flattened");
2949 Klass* k = o.klass();
2950 oop mirror = k->java_mirror();
2951 if (!CallbackInvoker::report_class_reference(o, mirror)) {
2952 return false;
2953 }
2954
2955 // report the array contents if required
2956 if (is_reporting_primitive_array_values()) {
2957 if (!CallbackInvoker::report_primitive_array_values(o)) {
2958 return false;
2959 }
2960 }
2961 return true;
2962 }
2963
2964 #ifdef ASSERT
2965 // verify that a static oop field is in range
2966 static inline bool verify_static_oop(InstanceKlass* ik,
2967 oop mirror, int offset) {
2968 address obj_p = cast_from_oop<address>(mirror) + offset;
2969 address start = (address)InstanceMirrorKlass::start_of_static_fields(mirror);
2970 address end = start + (java_lang_Class::static_oop_field_count(mirror) * heapOopSize);
2971 assert(end >= start, "sanity check");
2972
2973 if (obj_p >= start && obj_p < end) {
2974 return true;
2975 } else {
2976 return false;
2977 }
2978 }
2979 #endif // #ifdef ASSERT
2980
2981 // a class references its super class, interfaces, class loader, ...
2982 // and finally its static fields
2983 inline bool VM_HeapWalkOperation::iterate_over_class(const JvmtiHeapwalkObject& o) {
2984 assert(!o.is_flat(), "Klass object cannot be flattened");
2985 Klass* klass = java_lang_Class::as_Klass(o.obj());
2986 int i;
2987
2988 if (klass->is_instance_klass()) {
2989 InstanceKlass* ik = InstanceKlass::cast(klass);
2990
2991 // Ignore the class if it hasn't been initialized yet
2992 if (!ik->is_linked()) {
2993 return true;
2994 }
2995
2996 // get the java mirror
2997 oop mirror_oop = klass->java_mirror();
2998 JvmtiHeapwalkObject mirror(mirror_oop);
2999
3000 // super (only if something more interesting than java.lang.Object)
3001 InstanceKlass* super_klass = ik->super();
3002 if (super_klass != nullptr && super_klass != vmClasses::Object_klass()) {
3003 oop super_oop = super_klass->java_mirror();
3004 if (!CallbackInvoker::report_superclass_reference(mirror, super_oop)) {
3005 return false;
3006 }
3007 }
3008
3009 // class loader
3010 oop cl = ik->class_loader();
3011 if (cl != nullptr) {
3012 if (!CallbackInvoker::report_class_loader_reference(mirror, cl)) {
3013 return false;
3014 }
3015 }
3016
3017 // protection domain
3018 oop pd = ik->protection_domain();
3067 // (These will already have been reported as references from the constant pool
3068 // but are specified by IterateOverReachableObjects and must be reported).
3069 Array<InstanceKlass*>* interfaces = ik->local_interfaces();
3070 for (i = 0; i < interfaces->length(); i++) {
3071 oop interf = interfaces->at(i)->java_mirror();
3072 if (interf == nullptr) {
3073 continue;
3074 }
3075 if (!CallbackInvoker::report_interface_reference(mirror, interf)) {
3076 return false;
3077 }
3078 }
3079
3080 // iterate over the static fields
3081
3082 ClassFieldMap* field_map = ClassFieldMap::create_map_of_static_fields(klass);
3083 for (i=0; i<field_map->field_count(); i++) {
3084 ClassFieldDescriptor* field = field_map->field_at(i);
3085 char type = field->field_type();
3086 if (!is_primitive_field_type(type)) {
3087 oop fld_o = mirror_oop->obj_field(field->field_offset());
3088 assert(verify_static_oop(ik, mirror_oop, field->field_offset()), "sanity check");
3089 if (fld_o != nullptr) {
3090 int slot = field->field_index();
3091 if (!CallbackInvoker::report_static_field_reference(mirror, fld_o, slot)) {
3092 delete field_map;
3093 return false;
3094 }
3095 }
3096 } else {
3097 if (is_reporting_primitive_fields()) {
3098 address addr = cast_from_oop<address>(mirror_oop) + field->field_offset();
3099 int slot = field->field_index();
3100 if (!CallbackInvoker::report_primitive_static_field(mirror, slot, addr, type)) {
3101 delete field_map;
3102 return false;
3103 }
3104 }
3105 }
3106 }
3107 delete field_map;
3108
3109 return true;
3110 }
3111
3112 return true;
3113 }
3114
3115 // an object references a class and its instance fields
3116 // (static fields are ignored here as we report these as
3117 // references from the class).
3118 inline bool VM_HeapWalkOperation::iterate_over_object(const JvmtiHeapwalkObject& o) {
3119 // reference to the class
3120 if (!CallbackInvoker::report_class_reference(o, o.klass()->java_mirror())) {
3121 return false;
3122 }
3123
3124 // iterate over instance fields
3125 ClassFieldMap* field_map = JvmtiCachedClassFieldMap::get_map_of_instance_fields(o.klass());
3126 for (int i=0; i<field_map->field_count(); i++) {
3127 ClassFieldDescriptor* field = field_map->field_at(i);
3128 char type = field->field_type();
3129 int slot = field->field_index();
3130 int field_offset = field->field_offset();
3131 if (o.is_flat()) {
3132 // the object is inlined, its fields are stored without the header
3133 field_offset += o.offset() - o.inline_klass()->payload_offset();
3134 }
3135 if (!is_primitive_field_type(type)) {
3136 if (field->is_flat()) {
3137 // check for possible nulls
3138 if (LayoutKindHelper::is_nullable_flat(field->layout_kind())) {
3139 address payload = cast_from_oop<address>(o.obj()) + field_offset;
3140 if (field->inline_klass()->is_payload_marked_as_null(payload)) {
3141 continue;
3142 }
3143 }
3144 JvmtiHeapwalkObject field_obj(o.obj(), field_offset, field->inline_klass(), field->layout_kind());
3145 if (!CallbackInvoker::report_field_reference(o, field_obj, slot)) {
3146 return false;
3147 }
3148 } else {
3149 oop fld_o = o.obj()->obj_field_access<AS_NO_KEEPALIVE | ON_UNKNOWN_OOP_REF>(field_offset);
3150 // ignore any objects that aren't visible to profiler
3151 if (fld_o != nullptr) {
3152 assert(Universe::heap()->is_in(fld_o), "unsafe code should not have references to Klass* anymore");
3153 if (!CallbackInvoker::report_field_reference(o, fld_o, slot)) {
3154 return false;
3155 }
3156 }
3157 }
3158 } else {
3159 if (is_reporting_primitive_fields()) {
3160 // primitive instance field
3161 address addr = cast_from_oop<address>(o.obj()) + field_offset;
3162 if (!CallbackInvoker::report_primitive_instance_field(o, slot, addr, type)) {
3163 return false;
3164 }
3165 }
3166 }
3167 }
3168
3169 // if the object is a java.lang.String
3170 if (is_reporting_string_values() &&
3171 o.klass() == vmClasses::String_klass()) {
3172 if (!CallbackInvoker::report_string_value(o)) {
3173 return false;
3174 }
3175 }
3176 return true;
3177 }
3178
3179
3180 // Collects all simple (non-stack) roots except for threads;
3181 // threads are handled in collect_stack_roots() as an optimization.
3182 // if there's a heap root callback provided then the callback is
3183 // invoked for each simple root.
3184 // if an object reference callback is provided then all simple
3185 // roots are pushed onto the marking stack so that they can be
3186 // processed later
3187 //
3188 inline bool VM_HeapWalkOperation::collect_simple_roots() {
3189 SimpleRootsClosure blk;
3190
3191 // JNI globals
3220 // Reports the thread as JVMTI_HEAP_REFERENCE_THREAD,
3221 // walks the stack of the thread, finds all references (locals
3222 // and JNI calls) and reports these as stack references.
3223 inline bool VM_HeapWalkOperation::collect_stack_refs(JavaThread* java_thread,
3224 JNILocalRootsClosure* blk)
3225 {
3226 oop threadObj = java_thread->threadObj();
3227 oop mounted_vt = java_thread->is_vthread_mounted() ? java_thread->vthread() : nullptr;
3228 if (mounted_vt != nullptr && !JvmtiEnvBase::is_vthread_alive(mounted_vt)) {
3229 mounted_vt = nullptr;
3230 }
3231 assert(threadObj != nullptr, "sanity check");
3232
3233 StackRefCollector stack_collector(tag_map(), blk, java_thread);
3234
3235 if (!java_thread->has_last_Java_frame()) {
3236 if (!stack_collector.set_thread(JVMTI_HEAP_REFERENCE_THREAD, threadObj)) {
3237 return false;
3238 }
3239 // no last java frame but there may be JNI locals
3240 blk->set_context(_tag_map->find(threadObj), java_lang_Thread::thread_id(threadObj), 0, (jmethodID)nullptr);
3241 java_thread->active_handles()->oops_do(blk);
3242 return !blk->stopped();
3243 }
3244 // vframes are resource allocated
3245 Thread* current_thread = Thread::current();
3246 ResourceMark rm(current_thread);
3247 HandleMark hm(current_thread);
3248
3249 RegisterMap reg_map(java_thread,
3250 RegisterMap::UpdateMap::include,
3251 RegisterMap::ProcessFrames::include,
3252 RegisterMap::WalkContinuation::include);
3253
3254 // first handle mounted vthread (if any)
3255 if (mounted_vt != nullptr) {
3256 frame f = java_thread->last_frame();
3257 vframe* vf = vframe::new_vframe(&f, ®_map, java_thread);
3258 // report virtual thread as JVMTI_HEAP_REFERENCE_OTHER
3259 if (!stack_collector.set_thread(JVMTI_HEAP_REFERENCE_OTHER, mounted_vt)) {
3260 return false;
3320 RegisterMap reg_map(cont.continuation(), RegisterMap::UpdateMap::include);
3321
3322 JNILocalRootsClosure blk;
3323 // JavaThread is not required for unmounted virtual threads
3324 StackRefCollector stack_collector(tag_map(), &blk, nullptr);
3325 // reference to the vthread is already reported
3326 if (!stack_collector.set_thread(vt)) {
3327 return false;
3328 }
3329
3330 frame fr = chunk->top_frame(®_map);
3331 vframe* vf = vframe::new_vframe(&fr, ®_map, nullptr);
3332 return stack_collector.process_frames(vf);
3333 }
3334
3335 // visit an object
3336 // first mark the object as visited
3337 // second get all the outbound references from this object (in other words, all
3338 // the objects referenced by this object).
3339 //
3340 bool VM_HeapWalkOperation::visit(const JvmtiHeapwalkObject& o) {
3341 // mark object as visited
3342 assert(!visit_stack()->is_visited(o), "can't visit same object more than once");
3343 visit_stack()->mark_visited(o);
3344
3345 Klass* klass = o.klass();
3346 // instance
3347 if (klass->is_instance_klass()) {
3348 if (klass == vmClasses::Class_klass()) {
3349 assert(!o.is_flat(), "Class object cannot be flattened");
3350 if (!java_lang_Class::is_primitive(o.obj())) {
3351 // a java.lang.Class
3352 return iterate_over_class(o);
3353 }
3354 } else {
3355 // we report stack references only when initial object is not specified
3356 // (in the case we start from heap roots which include platform thread stack references)
3357 if (initial_object().is_null() && java_lang_VirtualThread::is_subclass(klass)) {
3358 assert(!o.is_flat(), "VirtualThread object cannot be flattened");
3359 if (!collect_vthread_stack_refs(o.obj())) {
3360 return false;
3361 }
3362 }
3363 return iterate_over_object(o);
3364 }
3365 }
3366
3367 // flat object array
3368 if (klass->is_flatArray_klass()) {
3369 return iterate_over_flat_array(o);
3370 }
3371
3372 // object array
3373 if (klass->is_objArray_klass()) {
3374 return iterate_over_array(o);
3375 }
3376
3377 // type array
3378 if (klass->is_typeArray_klass()) {
3379 return iterate_over_type_array(o);
3380 }
3381
3382 return true;
3383 }
3384
3385 void VM_HeapWalkOperation::doit() {
3386 ResourceMark rm;
3387 ClassFieldMapCacheMark cm;
3388
3389 JvmtiTagMap::check_hashmaps_for_heapwalk(_dead_objects);
3390
3391 assert(visit_stack()->is_empty(), "visit stack must be empty");
3392
3393 // the heap walk starts with an initial object or the heap roots
3394 if (initial_object().is_null()) {
3395 // can result in a big performance boost for an agent that is
3396 // focused on analyzing references in the thread stacks.
3397 if (!collect_stack_roots()) return;
3398
3399 if (!collect_simple_roots()) return;
3400 } else {
3401 visit_stack()->push(initial_object()());
3402 }
3403
3404 // object references required
3405 if (is_following_references()) {
3406
3407 // visit each object until all reachable objects have been
3408 // visited or the callback asked to terminate the iteration.
3409 while (!visit_stack()->is_empty()) {
3410 const JvmtiHeapwalkObject o = visit_stack()->pop();
3411 if (!visit_stack()->is_visited(o)) {
3412 if (!visit(o)) {
3413 break;
3414 }
3415 }
3416 }
3417 }
3418 }
3419
3420 // iterate over all objects that are reachable from a set of roots
3421 void JvmtiTagMap::iterate_over_reachable_objects(jvmtiHeapRootCallback heap_root_callback,
3422 jvmtiStackReferenceCallback stack_ref_callback,
3423 jvmtiObjectReferenceCallback object_ref_callback,
3424 const void* user_data) {
3425 // VTMS transitions must be disabled before the EscapeBarrier.
3426 MountUnmountDisabler disabler;
3427
3428 JavaThread* jt = JavaThread::current();
3429 EscapeBarrier eb(true, jt);
3430 eb.deoptimize_objects_all_threads();
3431 Arena dead_object_arena(mtServiceability);
3432 GrowableArray<jlong> dead_objects(&dead_object_arena, 10, 0, 0);
3433
3434 {
3435 MutexLocker ml(Heap_lock);
3436 BasicHeapWalkContext context(heap_root_callback, stack_ref_callback, object_ref_callback);
3437 VM_HeapWalkOperation op(this, Handle(), context, user_data, &dead_objects);
3438 VMThread::execute(&op);
3439 }
3440 convert_flat_object_entries();
3441
3442 // Post events outside of Heap_lock
3443 post_dead_objects(&dead_objects);
3444 }
3445
3446 // iterate over all objects that are reachable from a given object
3447 void JvmtiTagMap::iterate_over_objects_reachable_from_object(jobject object,
3448 jvmtiObjectReferenceCallback object_ref_callback,
3449 const void* user_data) {
3450 oop obj = JNIHandles::resolve(object);
3451 Handle initial_object(Thread::current(), obj);
3452
3453 Arena dead_object_arena(mtServiceability);
3454 GrowableArray<jlong> dead_objects(&dead_object_arena, 10, 0, 0);
3455
3456 MountUnmountDisabler disabler;
3457
3458 {
3459 MutexLocker ml(Heap_lock);
3460 BasicHeapWalkContext context(nullptr, nullptr, object_ref_callback);
3461 VM_HeapWalkOperation op(this, initial_object, context, user_data, &dead_objects);
3462 VMThread::execute(&op);
3463 }
3464 convert_flat_object_entries();
3465
3466 // Post events outside of Heap_lock
3467 post_dead_objects(&dead_objects);
3468 }
3469
3470 // follow references from an initial object or the GC roots
3471 void JvmtiTagMap::follow_references(jint heap_filter,
3472 Klass* klass,
3473 jobject object,
3474 const jvmtiHeapCallbacks* callbacks,
3475 const void* user_data)
3476 {
3477 // VTMS transitions must be disabled before the EscapeBarrier.
3478 MountUnmountDisabler disabler;
3479
3480 oop obj = JNIHandles::resolve(object);
3481 JavaThread* jt = JavaThread::current();
3482 Handle initial_object(jt, obj);
3483 // EA based optimizations that are tagged or reachable from initial_object are already reverted.
3484 EscapeBarrier eb(initial_object.is_null() &&
3485 !(heap_filter & JVMTI_HEAP_FILTER_UNTAGGED),
3486 jt);
3487 eb.deoptimize_objects_all_threads();
3488
3489 Arena dead_object_arena(mtServiceability);
3490 GrowableArray<jlong> dead_objects(&dead_object_arena, 10, 0, 0);
3491
3492 {
3493 MutexLocker ml(Heap_lock);
3494 AdvancedHeapWalkContext context(heap_filter, klass, callbacks);
3495 VM_HeapWalkOperation op(this, initial_object, context, user_data, &dead_objects);
3496 VMThread::execute(&op);
3497 }
3498 convert_flat_object_entries();
3499
3500 // Post events outside of Heap_lock
3501 post_dead_objects(&dead_objects);
3502 }
3503
3504 // Verify gc_notification follows set_needs_cleaning.
3505 DEBUG_ONLY(static bool notified_needs_cleaning = false;)
3506
3507 void JvmtiTagMap::set_needs_cleaning() {
3508 assert(SafepointSynchronize::is_at_safepoint(), "called in gc pause");
3509 assert(Thread::current()->is_VM_thread(), "should be the VM thread");
3510 // Can't assert !notified_needs_cleaning; a partial GC might be upgraded
3511 // to a full GC and do this twice without intervening gc_notification.
3512 DEBUG_ONLY(notified_needs_cleaning = true;)
3513
3514 JvmtiEnvIterator it;
3515 for (JvmtiEnv* env = it.first(); env != nullptr; env = it.next(env)) {
3516 JvmtiTagMap* tag_map = env->tag_map_acquire();
3517 if (tag_map != nullptr) {
3518 tag_map->_needs_cleaning = !tag_map->is_empty();
3519 }
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