1 /* 2 * Copyright (c) 2003, 2014, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "classfile/symbolTable.hpp" 27 #include "classfile/systemDictionary.hpp" 28 #include "classfile/vmSymbols.hpp" 29 #include "code/codeCache.hpp" 30 #include "jvmtifiles/jvmtiEnv.hpp" 31 #include "oops/instanceMirrorKlass.hpp" 32 #include "oops/markOop.inline.hpp" 33 #include "oops/objArrayKlass.hpp" 34 #include "oops/oop.inline.hpp" 35 #include "oops/oop.inline2.hpp" 36 #include "prims/jvmtiEventController.hpp" 37 #include "prims/jvmtiEventController.inline.hpp" 38 #include "prims/jvmtiExport.hpp" 39 #include "prims/jvmtiImpl.hpp" 40 #include "prims/jvmtiTagMap.hpp" 41 #include "runtime/biasedLocking.hpp" 42 #include "runtime/javaCalls.hpp" 43 #include "runtime/jniHandles.hpp" 44 #include "runtime/mutex.hpp" 45 #include "runtime/mutexLocker.hpp" 46 #include "runtime/reflectionUtils.hpp" 47 #include "runtime/vframe.hpp" 48 #include "runtime/vmThread.hpp" 49 #include "runtime/vm_operations.hpp" 50 #include "services/serviceUtil.hpp" 51 #include "utilities/macros.hpp" 52 #if INCLUDE_ALL_GCS 53 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp" 54 #endif // INCLUDE_ALL_GCS 55 56 // JvmtiTagHashmapEntry 57 // 58 // Each entry encapsulates a reference to the tagged object 59 // and the tag value. In addition an entry includes a next pointer which 60 // is used to chain entries together. 61 62 class JvmtiTagHashmapEntry : public CHeapObj<mtInternal> { 63 private: 64 friend class JvmtiTagMap; 65 66 oop _object; // tagged object 67 jlong _tag; // the tag 68 JvmtiTagHashmapEntry* _next; // next on the list 69 70 inline void init(oop object, jlong tag) { 71 _object = object; 72 _tag = tag; 73 _next = NULL; 74 } 75 76 // constructor 77 JvmtiTagHashmapEntry(oop object, jlong tag) { init(object, tag); } 78 79 public: 80 81 // accessor methods 82 inline oop object() const { return _object; } 83 inline oop* object_addr() { return &_object; } 84 inline jlong tag() const { return _tag; } 85 86 inline void set_tag(jlong tag) { 87 assert(tag != 0, "can't be zero"); 88 _tag = tag; 89 } 90 91 inline JvmtiTagHashmapEntry* next() const { return _next; } 92 inline void set_next(JvmtiTagHashmapEntry* next) { _next = next; } 93 }; 94 95 96 // JvmtiTagHashmap 97 // 98 // A hashmap is essentially a table of pointers to entries. Entries 99 // are hashed to a location, or position in the table, and then 100 // chained from that location. The "key" for hashing is address of 101 // the object, or oop. The "value" is the tag value. 102 // 103 // A hashmap maintains a count of the number entries in the hashmap 104 // and resizes if the number of entries exceeds a given threshold. 105 // The threshold is specified as a percentage of the size - for 106 // example a threshold of 0.75 will trigger the hashmap to resize 107 // if the number of entries is >75% of table size. 108 // 109 // A hashmap provides functions for adding, removing, and finding 110 // entries. It also provides a function to iterate over all entries 111 // in the hashmap. 112 113 class JvmtiTagHashmap : public CHeapObj<mtInternal> { 114 private: 115 friend class JvmtiTagMap; 116 117 enum { 118 small_trace_threshold = 10000, // threshold for tracing 119 medium_trace_threshold = 100000, 120 large_trace_threshold = 1000000, 121 initial_trace_threshold = small_trace_threshold 122 }; 123 124 static int _sizes[]; // array of possible hashmap sizes 125 int _size; // actual size of the table 126 int _size_index; // index into size table 127 128 int _entry_count; // number of entries in the hashmap 129 130 float _load_factor; // load factor as a % of the size 131 int _resize_threshold; // computed threshold to trigger resizing. 132 bool _resizing_enabled; // indicates if hashmap can resize 133 134 int _trace_threshold; // threshold for trace messages 135 136 JvmtiTagHashmapEntry** _table; // the table of entries. 137 138 // private accessors 139 int resize_threshold() const { return _resize_threshold; } 140 int trace_threshold() const { return _trace_threshold; } 141 142 // initialize the hashmap 143 void init(int size_index=0, float load_factor=4.0f) { 144 int initial_size = _sizes[size_index]; 145 _size_index = size_index; 146 _size = initial_size; 147 _entry_count = 0; 148 if (TraceJVMTIObjectTagging) { 149 _trace_threshold = initial_trace_threshold; 150 } else { 151 _trace_threshold = -1; 152 } 153 _load_factor = load_factor; 154 _resize_threshold = (int)(_load_factor * _size); 155 _resizing_enabled = true; 156 size_t s = initial_size * sizeof(JvmtiTagHashmapEntry*); 157 _table = (JvmtiTagHashmapEntry**)os::malloc(s, mtInternal); 158 if (_table == NULL) { 159 vm_exit_out_of_memory(s, OOM_MALLOC_ERROR, 160 "unable to allocate initial hashtable for jvmti object tags"); 161 } 162 for (int i=0; i<initial_size; i++) { 163 _table[i] = NULL; 164 } 165 } 166 167 // hash a given key (oop) with the specified size 168 static unsigned int hash(oop key, int size) { 169 // shift right to get better distribution (as these bits will be zero 170 // with aligned addresses) 171 unsigned int addr = (unsigned int)(cast_from_oop<intptr_t>(key)); 172 #ifdef _LP64 173 return (addr >> 3) % size; 174 #else 175 return (addr >> 2) % size; 176 #endif 177 } 178 179 // hash a given key (oop) 180 unsigned int hash(oop key) { 181 return hash(key, _size); 182 } 183 184 // resize the hashmap - allocates a large table and re-hashes 185 // all entries into the new table. 186 void resize() { 187 int new_size_index = _size_index+1; 188 int new_size = _sizes[new_size_index]; 189 if (new_size < 0) { 190 // hashmap already at maximum capacity 191 return; 192 } 193 194 // allocate new table 195 size_t s = new_size * sizeof(JvmtiTagHashmapEntry*); 196 JvmtiTagHashmapEntry** new_table = (JvmtiTagHashmapEntry**)os::malloc(s, mtInternal); 197 if (new_table == NULL) { 198 warning("unable to allocate larger hashtable for jvmti object tags"); 199 set_resizing_enabled(false); 200 return; 201 } 202 203 // initialize new table 204 int i; 205 for (i=0; i<new_size; i++) { 206 new_table[i] = NULL; 207 } 208 209 // rehash all entries into the new table 210 for (i=0; i<_size; i++) { 211 JvmtiTagHashmapEntry* entry = _table[i]; 212 while (entry != NULL) { 213 JvmtiTagHashmapEntry* next = entry->next(); 214 oop key = entry->object(); 215 assert(key != NULL, "jni weak reference cleared!!"); 216 unsigned int h = hash(key, new_size); 217 JvmtiTagHashmapEntry* anchor = new_table[h]; 218 if (anchor == NULL) { 219 new_table[h] = entry; 220 entry->set_next(NULL); 221 } else { 222 entry->set_next(anchor); 223 new_table[h] = entry; 224 } 225 entry = next; 226 } 227 } 228 229 // free old table and update settings. 230 os::free((void*)_table); 231 _table = new_table; 232 _size_index = new_size_index; 233 _size = new_size; 234 235 // compute new resize threshold 236 _resize_threshold = (int)(_load_factor * _size); 237 } 238 239 240 // internal remove function - remove an entry at a given position in the 241 // table. 242 inline void remove(JvmtiTagHashmapEntry* prev, int pos, JvmtiTagHashmapEntry* entry) { 243 assert(pos >= 0 && pos < _size, "out of range"); 244 if (prev == NULL) { 245 _table[pos] = entry->next(); 246 } else { 247 prev->set_next(entry->next()); 248 } 249 assert(_entry_count > 0, "checking"); 250 _entry_count--; 251 } 252 253 // resizing switch 254 bool is_resizing_enabled() const { return _resizing_enabled; } 255 void set_resizing_enabled(bool enable) { _resizing_enabled = enable; } 256 257 // debugging 258 void print_memory_usage(); 259 void compute_next_trace_threshold(); 260 261 public: 262 263 // create a JvmtiTagHashmap of a preferred size and optionally a load factor. 264 // The preferred size is rounded down to an actual size. 265 JvmtiTagHashmap(int size, float load_factor=0.0f) { 266 int i=0; 267 while (_sizes[i] < size) { 268 if (_sizes[i] < 0) { 269 assert(i > 0, "sanity check"); 270 i--; 271 break; 272 } 273 i++; 274 } 275 276 // if a load factor is specified then use it, otherwise use default 277 if (load_factor > 0.01f) { 278 init(i, load_factor); 279 } else { 280 init(i); 281 } 282 } 283 284 // create a JvmtiTagHashmap with default settings 285 JvmtiTagHashmap() { 286 init(); 287 } 288 289 // release table when JvmtiTagHashmap destroyed 290 ~JvmtiTagHashmap() { 291 if (_table != NULL) { 292 os::free((void*)_table); 293 _table = NULL; 294 } 295 } 296 297 // accessors 298 int size() const { return _size; } 299 JvmtiTagHashmapEntry** table() const { return _table; } 300 int entry_count() const { return _entry_count; } 301 302 // find an entry in the hashmap, returns NULL if not found. 303 inline JvmtiTagHashmapEntry* find(oop key) { 304 unsigned int h = hash(key); 305 JvmtiTagHashmapEntry* entry = _table[h]; 306 while (entry != NULL) { 307 if (entry->object() == key) { 308 return entry; 309 } 310 entry = entry->next(); 311 } 312 return NULL; 313 } 314 315 316 // add a new entry to hashmap 317 inline void add(oop key, JvmtiTagHashmapEntry* entry) { 318 assert(key != NULL, "checking"); 319 assert(find(key) == NULL, "duplicate detected"); 320 unsigned int h = hash(key); 321 JvmtiTagHashmapEntry* anchor = _table[h]; 322 if (anchor == NULL) { 323 _table[h] = entry; 324 entry->set_next(NULL); 325 } else { 326 entry->set_next(anchor); 327 _table[h] = entry; 328 } 329 330 _entry_count++; 331 if (trace_threshold() > 0 && entry_count() >= trace_threshold()) { 332 assert(TraceJVMTIObjectTagging, "should only get here when tracing"); 333 print_memory_usage(); 334 compute_next_trace_threshold(); 335 } 336 337 // if the number of entries exceed the threshold then resize 338 if (entry_count() > resize_threshold() && is_resizing_enabled()) { 339 resize(); 340 } 341 } 342 343 // remove an entry with the given key. 344 inline JvmtiTagHashmapEntry* remove(oop key) { 345 unsigned int h = hash(key); 346 JvmtiTagHashmapEntry* entry = _table[h]; 347 JvmtiTagHashmapEntry* prev = NULL; 348 while (entry != NULL) { 349 if (key == entry->object()) { 350 break; 351 } 352 prev = entry; 353 entry = entry->next(); 354 } 355 if (entry != NULL) { 356 remove(prev, h, entry); 357 } 358 return entry; 359 } 360 361 // iterate over all entries in the hashmap 362 void entry_iterate(JvmtiTagHashmapEntryClosure* closure); 363 }; 364 365 // possible hashmap sizes - odd primes that roughly double in size. 366 // To avoid excessive resizing the odd primes from 4801-76831 and 367 // 76831-307261 have been removed. The list must be terminated by -1. 368 int JvmtiTagHashmap::_sizes[] = { 4801, 76831, 307261, 614563, 1228891, 369 2457733, 4915219, 9830479, 19660831, 39321619, 78643219, -1 }; 370 371 372 // A supporting class for iterating over all entries in Hashmap 373 class JvmtiTagHashmapEntryClosure { 374 public: 375 virtual void do_entry(JvmtiTagHashmapEntry* entry) = 0; 376 }; 377 378 379 // iterate over all entries in the hashmap 380 void JvmtiTagHashmap::entry_iterate(JvmtiTagHashmapEntryClosure* closure) { 381 for (int i=0; i<_size; i++) { 382 JvmtiTagHashmapEntry* entry = _table[i]; 383 JvmtiTagHashmapEntry* prev = NULL; 384 while (entry != NULL) { 385 // obtain the next entry before invoking do_entry - this is 386 // necessary because do_entry may remove the entry from the 387 // hashmap. 388 JvmtiTagHashmapEntry* next = entry->next(); 389 closure->do_entry(entry); 390 entry = next; 391 } 392 } 393 } 394 395 // debugging 396 void JvmtiTagHashmap::print_memory_usage() { 397 intptr_t p = (intptr_t)this; 398 tty->print("[JvmtiTagHashmap @ " INTPTR_FORMAT, p); 399 400 // table + entries in KB 401 int hashmap_usage = (size()*sizeof(JvmtiTagHashmapEntry*) + 402 entry_count()*sizeof(JvmtiTagHashmapEntry))/K; 403 404 int weak_globals_usage = (int)(JNIHandles::weak_global_handle_memory_usage()/K); 405 tty->print_cr(", %d entries (%d KB) <JNI weak globals: %d KB>]", 406 entry_count(), hashmap_usage, weak_globals_usage); 407 } 408 409 // compute threshold for the next trace message 410 void JvmtiTagHashmap::compute_next_trace_threshold() { 411 if (trace_threshold() < medium_trace_threshold) { 412 _trace_threshold += small_trace_threshold; 413 } else { 414 if (trace_threshold() < large_trace_threshold) { 415 _trace_threshold += medium_trace_threshold; 416 } else { 417 _trace_threshold += large_trace_threshold; 418 } 419 } 420 } 421 422 // create a JvmtiTagMap 423 JvmtiTagMap::JvmtiTagMap(JvmtiEnv* env) : 424 _env(env), 425 _lock(Mutex::nonleaf+2, "JvmtiTagMap._lock", false), 426 _free_entries(NULL), 427 _free_entries_count(0) 428 { 429 assert(JvmtiThreadState_lock->is_locked(), "sanity check"); 430 assert(((JvmtiEnvBase *)env)->tag_map() == NULL, "tag map already exists for environment"); 431 432 _hashmap = new JvmtiTagHashmap(); 433 434 // finally add us to the environment 435 ((JvmtiEnvBase *)env)->set_tag_map(this); 436 } 437 438 439 // destroy a JvmtiTagMap 440 JvmtiTagMap::~JvmtiTagMap() { 441 442 // no lock acquired as we assume the enclosing environment is 443 // also being destroryed. 444 ((JvmtiEnvBase *)_env)->set_tag_map(NULL); 445 446 JvmtiTagHashmapEntry** table = _hashmap->table(); 447 for (int j = 0; j < _hashmap->size(); j++) { 448 JvmtiTagHashmapEntry* entry = table[j]; 449 while (entry != NULL) { 450 JvmtiTagHashmapEntry* next = entry->next(); 451 delete entry; 452 entry = next; 453 } 454 } 455 456 // finally destroy the hashmap 457 delete _hashmap; 458 _hashmap = NULL; 459 460 // remove any entries on the free list 461 JvmtiTagHashmapEntry* entry = _free_entries; 462 while (entry != NULL) { 463 JvmtiTagHashmapEntry* next = entry->next(); 464 delete entry; 465 entry = next; 466 } 467 _free_entries = NULL; 468 } 469 470 // create a hashmap entry 471 // - if there's an entry on the (per-environment) free list then this 472 // is returned. Otherwise an new entry is allocated. 473 JvmtiTagHashmapEntry* JvmtiTagMap::create_entry(oop ref, jlong tag) { 474 assert(Thread::current()->is_VM_thread() || is_locked(), "checking"); 475 JvmtiTagHashmapEntry* entry; 476 if (_free_entries == NULL) { 477 entry = new JvmtiTagHashmapEntry(ref, tag); 478 } else { 479 assert(_free_entries_count > 0, "mismatched _free_entries_count"); 480 _free_entries_count--; 481 entry = _free_entries; 482 _free_entries = entry->next(); 483 entry->init(ref, tag); 484 } 485 return entry; 486 } 487 488 // destroy an entry by returning it to the free list 489 void JvmtiTagMap::destroy_entry(JvmtiTagHashmapEntry* entry) { 490 assert(SafepointSynchronize::is_at_safepoint() || is_locked(), "checking"); 491 // limit the size of the free list 492 if (_free_entries_count >= max_free_entries) { 493 delete entry; 494 } else { 495 entry->set_next(_free_entries); 496 _free_entries = entry; 497 _free_entries_count++; 498 } 499 } 500 501 // returns the tag map for the given environments. If the tag map 502 // doesn't exist then it is created. 503 JvmtiTagMap* JvmtiTagMap::tag_map_for(JvmtiEnv* env) { 504 JvmtiTagMap* tag_map = ((JvmtiEnvBase*)env)->tag_map(); 505 if (tag_map == NULL) { 506 MutexLocker mu(JvmtiThreadState_lock); 507 tag_map = ((JvmtiEnvBase*)env)->tag_map(); 508 if (tag_map == NULL) { 509 tag_map = new JvmtiTagMap(env); 510 } 511 } else { 512 CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops()); 513 } 514 return tag_map; 515 } 516 517 // iterate over all entries in the tag map. 518 void JvmtiTagMap::entry_iterate(JvmtiTagHashmapEntryClosure* closure) { 519 hashmap()->entry_iterate(closure); 520 } 521 522 // returns true if the hashmaps are empty 523 bool JvmtiTagMap::is_empty() { 524 assert(SafepointSynchronize::is_at_safepoint() || is_locked(), "checking"); 525 return hashmap()->entry_count() == 0; 526 } 527 528 529 // Return the tag value for an object, or 0 if the object is 530 // not tagged 531 // 532 static inline jlong tag_for(JvmtiTagMap* tag_map, oop o) { 533 JvmtiTagHashmapEntry* entry = tag_map->hashmap()->find(o); 534 if (entry == NULL) { 535 return 0; 536 } else { 537 return entry->tag(); 538 } 539 } 540 541 542 // A CallbackWrapper is a support class for querying and tagging an object 543 // around a callback to a profiler. The constructor does pre-callback 544 // work to get the tag value, klass tag value, ... and the destructor 545 // does the post-callback work of tagging or untagging the object. 546 // 547 // { 548 // CallbackWrapper wrapper(tag_map, o); 549 // 550 // (*callback)(wrapper.klass_tag(), wrapper.obj_size(), wrapper.obj_tag_p(), ...) 551 // 552 // } // wrapper goes out of scope here which results in the destructor 553 // checking to see if the object has been tagged, untagged, or the 554 // tag value has changed. 555 // 556 class CallbackWrapper : public StackObj { 557 private: 558 JvmtiTagMap* _tag_map; 559 JvmtiTagHashmap* _hashmap; 560 JvmtiTagHashmapEntry* _entry; 561 oop _o; 562 jlong _obj_size; 563 jlong _obj_tag; 564 jlong _klass_tag; 565 566 protected: 567 JvmtiTagMap* tag_map() const { return _tag_map; } 568 569 // invoked post-callback to tag, untag, or update the tag of an object 570 void inline post_callback_tag_update(oop o, JvmtiTagHashmap* hashmap, 571 JvmtiTagHashmapEntry* entry, jlong obj_tag); 572 public: 573 CallbackWrapper(JvmtiTagMap* tag_map, oop o) { 574 assert(Thread::current()->is_VM_thread() || tag_map->is_locked(), 575 "MT unsafe or must be VM thread"); 576 577 // object to tag 578 _o = o; 579 580 // object size 581 _obj_size = (jlong)_o->size() * wordSize; 582 583 // record the context 584 _tag_map = tag_map; 585 _hashmap = tag_map->hashmap(); 586 _entry = _hashmap->find(_o); 587 588 // get object tag 589 _obj_tag = (_entry == NULL) ? 0 : _entry->tag(); 590 591 // get the class and the class's tag value 592 assert(SystemDictionary::Class_klass()->oop_is_instanceMirror(), "Is not?"); 593 594 _klass_tag = tag_for(tag_map, _o->klass()->java_mirror()); 595 } 596 597 ~CallbackWrapper() { 598 post_callback_tag_update(_o, _hashmap, _entry, _obj_tag); 599 } 600 601 inline jlong* obj_tag_p() { return &_obj_tag; } 602 inline jlong obj_size() const { return _obj_size; } 603 inline jlong obj_tag() const { return _obj_tag; } 604 inline jlong klass_tag() const { return _klass_tag; } 605 }; 606 607 608 609 // callback post-callback to tag, untag, or update the tag of an object 610 void inline CallbackWrapper::post_callback_tag_update(oop o, 611 JvmtiTagHashmap* hashmap, 612 JvmtiTagHashmapEntry* entry, 613 jlong obj_tag) { 614 if (entry == NULL) { 615 if (obj_tag != 0) { 616 // callback has tagged the object 617 assert(Thread::current()->is_VM_thread(), "must be VMThread"); 618 entry = tag_map()->create_entry(o, obj_tag); 619 hashmap->add(o, entry); 620 } 621 } else { 622 // object was previously tagged - the callback may have untagged 623 // the object or changed the tag value 624 if (obj_tag == 0) { 625 626 JvmtiTagHashmapEntry* entry_removed = hashmap->remove(o); 627 assert(entry_removed == entry, "checking"); 628 tag_map()->destroy_entry(entry); 629 630 } else { 631 if (obj_tag != entry->tag()) { 632 entry->set_tag(obj_tag); 633 } 634 } 635 } 636 } 637 638 // An extended CallbackWrapper used when reporting an object reference 639 // to the agent. 640 // 641 // { 642 // TwoOopCallbackWrapper wrapper(tag_map, referrer, o); 643 // 644 // (*callback)(wrapper.klass_tag(), 645 // wrapper.obj_size(), 646 // wrapper.obj_tag_p() 647 // wrapper.referrer_tag_p(), ...) 648 // 649 // } // wrapper goes out of scope here which results in the destructor 650 // checking to see if the referrer object has been tagged, untagged, 651 // or the tag value has changed. 652 // 653 class TwoOopCallbackWrapper : public CallbackWrapper { 654 private: 655 bool _is_reference_to_self; 656 JvmtiTagHashmap* _referrer_hashmap; 657 JvmtiTagHashmapEntry* _referrer_entry; 658 oop _referrer; 659 jlong _referrer_obj_tag; 660 jlong _referrer_klass_tag; 661 jlong* _referrer_tag_p; 662 663 bool is_reference_to_self() const { return _is_reference_to_self; } 664 665 public: 666 TwoOopCallbackWrapper(JvmtiTagMap* tag_map, oop referrer, oop o) : 667 CallbackWrapper(tag_map, o) 668 { 669 // self reference needs to be handled in a special way 670 _is_reference_to_self = (referrer == o); 671 672 if (_is_reference_to_self) { 673 _referrer_klass_tag = klass_tag(); 674 _referrer_tag_p = obj_tag_p(); 675 } else { 676 _referrer = referrer; 677 // record the context 678 _referrer_hashmap = tag_map->hashmap(); 679 _referrer_entry = _referrer_hashmap->find(_referrer); 680 681 // get object tag 682 _referrer_obj_tag = (_referrer_entry == NULL) ? 0 : _referrer_entry->tag(); 683 _referrer_tag_p = &_referrer_obj_tag; 684 685 // get referrer class tag. 686 _referrer_klass_tag = tag_for(tag_map, _referrer->klass()->java_mirror()); 687 } 688 } 689 690 ~TwoOopCallbackWrapper() { 691 if (!is_reference_to_self()){ 692 post_callback_tag_update(_referrer, 693 _referrer_hashmap, 694 _referrer_entry, 695 _referrer_obj_tag); 696 } 697 } 698 699 // address of referrer tag 700 // (for a self reference this will return the same thing as obj_tag_p()) 701 inline jlong* referrer_tag_p() { return _referrer_tag_p; } 702 703 // referrer's class tag 704 inline jlong referrer_klass_tag() { return _referrer_klass_tag; } 705 }; 706 707 // tag an object 708 // 709 // This function is performance critical. If many threads attempt to tag objects 710 // around the same time then it's possible that the Mutex associated with the 711 // tag map will be a hot lock. 712 void JvmtiTagMap::set_tag(jobject object, jlong tag) { 713 MutexLocker ml(lock()); 714 715 // resolve the object 716 oop o = JNIHandles::resolve_non_null(object); 717 718 // see if the object is already tagged 719 JvmtiTagHashmap* hashmap = _hashmap; 720 JvmtiTagHashmapEntry* entry = hashmap->find(o); 721 722 // if the object is not already tagged then we tag it 723 if (entry == NULL) { 724 if (tag != 0) { 725 entry = create_entry(o, tag); 726 hashmap->add(o, entry); 727 } else { 728 // no-op 729 } 730 } else { 731 // if the object is already tagged then we either update 732 // the tag (if a new tag value has been provided) 733 // or remove the object if the new tag value is 0. 734 if (tag == 0) { 735 hashmap->remove(o); 736 destroy_entry(entry); 737 } else { 738 entry->set_tag(tag); 739 } 740 } 741 } 742 743 // get the tag for an object 744 jlong JvmtiTagMap::get_tag(jobject object) { 745 MutexLocker ml(lock()); 746 747 // resolve the object 748 oop o = JNIHandles::resolve_non_null(object); 749 750 return tag_for(this, o); 751 } 752 753 754 // Helper class used to describe the static or instance fields of a class. 755 // For each field it holds the field index (as defined by the JVMTI specification), 756 // the field type, and the offset. 757 758 class ClassFieldDescriptor: public CHeapObj<mtInternal> { 759 private: 760 int _field_index; 761 int _field_offset; 762 char _field_type; 763 public: 764 ClassFieldDescriptor(int index, char type, int offset) : 765 _field_index(index), _field_type(type), _field_offset(offset) { 766 } 767 int field_index() const { return _field_index; } 768 char field_type() const { return _field_type; } 769 int field_offset() const { return _field_offset; } 770 }; 771 772 class ClassFieldMap: public CHeapObj<mtInternal> { 773 private: 774 enum { 775 initial_field_count = 5 776 }; 777 778 // list of field descriptors 779 GrowableArray<ClassFieldDescriptor*>* _fields; 780 781 // constructor 782 ClassFieldMap(); 783 784 // add a field 785 void add(int index, char type, int offset); 786 787 // returns the field count for the given class 788 static int compute_field_count(instanceKlassHandle ikh); 789 790 public: 791 ~ClassFieldMap(); 792 793 // access 794 int field_count() { return _fields->length(); } 795 ClassFieldDescriptor* field_at(int i) { return _fields->at(i); } 796 797 // functions to create maps of static or instance fields 798 static ClassFieldMap* create_map_of_static_fields(Klass* k); 799 static ClassFieldMap* create_map_of_instance_fields(oop obj); 800 }; 801 802 ClassFieldMap::ClassFieldMap() { 803 _fields = new (ResourceObj::C_HEAP, mtInternal) 804 GrowableArray<ClassFieldDescriptor*>(initial_field_count, true); 805 } 806 807 ClassFieldMap::~ClassFieldMap() { 808 for (int i=0; i<_fields->length(); i++) { 809 delete _fields->at(i); 810 } 811 delete _fields; 812 } 813 814 void ClassFieldMap::add(int index, char type, int offset) { 815 ClassFieldDescriptor* field = new ClassFieldDescriptor(index, type, offset); 816 _fields->append(field); 817 } 818 819 // Returns a heap allocated ClassFieldMap to describe the static fields 820 // of the given class. 821 // 822 ClassFieldMap* ClassFieldMap::create_map_of_static_fields(Klass* k) { 823 HandleMark hm; 824 instanceKlassHandle ikh = instanceKlassHandle(Thread::current(), k); 825 826 // create the field map 827 ClassFieldMap* field_map = new ClassFieldMap(); 828 829 FilteredFieldStream f(ikh, false, false); 830 int max_field_index = f.field_count()-1; 831 832 int index = 0; 833 for (FilteredFieldStream fld(ikh, true, true); !fld.eos(); fld.next(), index++) { 834 // ignore instance fields 835 if (!fld.access_flags().is_static()) { 836 continue; 837 } 838 field_map->add(max_field_index - index, fld.signature()->byte_at(0), fld.offset()); 839 } 840 return field_map; 841 } 842 843 // Returns a heap allocated ClassFieldMap to describe the instance fields 844 // of the given class. All instance fields are included (this means public 845 // and private fields declared in superclasses and superinterfaces too). 846 // 847 ClassFieldMap* ClassFieldMap::create_map_of_instance_fields(oop obj) { 848 HandleMark hm; 849 instanceKlassHandle ikh = instanceKlassHandle(Thread::current(), obj->klass()); 850 851 // create the field map 852 ClassFieldMap* field_map = new ClassFieldMap(); 853 854 FilteredFieldStream f(ikh, false, false); 855 856 int max_field_index = f.field_count()-1; 857 858 int index = 0; 859 for (FilteredFieldStream fld(ikh, false, false); !fld.eos(); fld.next(), index++) { 860 // ignore static fields 861 if (fld.access_flags().is_static()) { 862 continue; 863 } 864 field_map->add(max_field_index - index, fld.signature()->byte_at(0), fld.offset()); 865 } 866 867 return field_map; 868 } 869 870 // Helper class used to cache a ClassFileMap for the instance fields of 871 // a cache. A JvmtiCachedClassFieldMap can be cached by an InstanceKlass during 872 // heap iteration and avoid creating a field map for each object in the heap 873 // (only need to create the map when the first instance of a class is encountered). 874 // 875 class JvmtiCachedClassFieldMap : public CHeapObj<mtInternal> { 876 private: 877 enum { 878 initial_class_count = 200 879 }; 880 ClassFieldMap* _field_map; 881 882 ClassFieldMap* field_map() const { return _field_map; } 883 884 JvmtiCachedClassFieldMap(ClassFieldMap* field_map); 885 ~JvmtiCachedClassFieldMap(); 886 887 static GrowableArray<InstanceKlass*>* _class_list; 888 static void add_to_class_list(InstanceKlass* ik); 889 890 public: 891 // returns the field map for a given object (returning map cached 892 // by InstanceKlass if possible 893 static ClassFieldMap* get_map_of_instance_fields(oop obj); 894 895 // removes the field map from all instanceKlasses - should be 896 // called before VM operation completes 897 static void clear_cache(); 898 899 // returns the number of ClassFieldMap cached by instanceKlasses 900 static int cached_field_map_count(); 901 }; 902 903 GrowableArray<InstanceKlass*>* JvmtiCachedClassFieldMap::_class_list; 904 905 JvmtiCachedClassFieldMap::JvmtiCachedClassFieldMap(ClassFieldMap* field_map) { 906 _field_map = field_map; 907 } 908 909 JvmtiCachedClassFieldMap::~JvmtiCachedClassFieldMap() { 910 if (_field_map != NULL) { 911 delete _field_map; 912 } 913 } 914 915 // Marker class to ensure that the class file map cache is only used in a defined 916 // scope. 917 class ClassFieldMapCacheMark : public StackObj { 918 private: 919 static bool _is_active; 920 public: 921 ClassFieldMapCacheMark() { 922 assert(Thread::current()->is_VM_thread(), "must be VMThread"); 923 assert(JvmtiCachedClassFieldMap::cached_field_map_count() == 0, "cache not empty"); 924 assert(!_is_active, "ClassFieldMapCacheMark cannot be nested"); 925 _is_active = true; 926 } 927 ~ClassFieldMapCacheMark() { 928 JvmtiCachedClassFieldMap::clear_cache(); 929 _is_active = false; 930 } 931 static bool is_active() { return _is_active; } 932 }; 933 934 bool ClassFieldMapCacheMark::_is_active; 935 936 937 // record that the given InstanceKlass is caching a field map 938 void JvmtiCachedClassFieldMap::add_to_class_list(InstanceKlass* ik) { 939 if (_class_list == NULL) { 940 _class_list = new (ResourceObj::C_HEAP, mtInternal) 941 GrowableArray<InstanceKlass*>(initial_class_count, true); 942 } 943 _class_list->push(ik); 944 } 945 946 // returns the instance field map for the given object 947 // (returns field map cached by the InstanceKlass if possible) 948 ClassFieldMap* JvmtiCachedClassFieldMap::get_map_of_instance_fields(oop obj) { 949 assert(Thread::current()->is_VM_thread(), "must be VMThread"); 950 assert(ClassFieldMapCacheMark::is_active(), "ClassFieldMapCacheMark not active"); 951 952 Klass* k = obj->klass(); 953 InstanceKlass* ik = InstanceKlass::cast(k); 954 955 // return cached map if possible 956 JvmtiCachedClassFieldMap* cached_map = ik->jvmti_cached_class_field_map(); 957 if (cached_map != NULL) { 958 assert(cached_map->field_map() != NULL, "missing field list"); 959 return cached_map->field_map(); 960 } else { 961 ClassFieldMap* field_map = ClassFieldMap::create_map_of_instance_fields(obj); 962 cached_map = new JvmtiCachedClassFieldMap(field_map); 963 ik->set_jvmti_cached_class_field_map(cached_map); 964 add_to_class_list(ik); 965 return field_map; 966 } 967 } 968 969 // remove the fields maps cached from all instanceKlasses 970 void JvmtiCachedClassFieldMap::clear_cache() { 971 assert(Thread::current()->is_VM_thread(), "must be VMThread"); 972 if (_class_list != NULL) { 973 for (int i = 0; i < _class_list->length(); i++) { 974 InstanceKlass* ik = _class_list->at(i); 975 JvmtiCachedClassFieldMap* cached_map = ik->jvmti_cached_class_field_map(); 976 assert(cached_map != NULL, "should not be NULL"); 977 ik->set_jvmti_cached_class_field_map(NULL); 978 delete cached_map; // deletes the encapsulated field map 979 } 980 delete _class_list; 981 _class_list = NULL; 982 } 983 } 984 985 // returns the number of ClassFieldMap cached by instanceKlasses 986 int JvmtiCachedClassFieldMap::cached_field_map_count() { 987 return (_class_list == NULL) ? 0 : _class_list->length(); 988 } 989 990 // helper function to indicate if an object is filtered by its tag or class tag 991 static inline bool is_filtered_by_heap_filter(jlong obj_tag, 992 jlong klass_tag, 993 int heap_filter) { 994 // apply the heap filter 995 if (obj_tag != 0) { 996 // filter out tagged objects 997 if (heap_filter & JVMTI_HEAP_FILTER_TAGGED) return true; 998 } else { 999 // filter out untagged objects 1000 if (heap_filter & JVMTI_HEAP_FILTER_UNTAGGED) return true; 1001 } 1002 if (klass_tag != 0) { 1003 // filter out objects with tagged classes 1004 if (heap_filter & JVMTI_HEAP_FILTER_CLASS_TAGGED) return true; 1005 } else { 1006 // filter out objects with untagged classes. 1007 if (heap_filter & JVMTI_HEAP_FILTER_CLASS_UNTAGGED) return true; 1008 } 1009 return false; 1010 } 1011 1012 // helper function to indicate if an object is filtered by a klass filter 1013 static inline bool is_filtered_by_klass_filter(oop obj, KlassHandle klass_filter) { 1014 if (!klass_filter.is_null()) { 1015 if (obj->klass() != klass_filter()) { 1016 return true; 1017 } 1018 } 1019 return false; 1020 } 1021 1022 // helper function to tell if a field is a primitive field or not 1023 static inline bool is_primitive_field_type(char type) { 1024 return (type != 'L' && type != '['); 1025 } 1026 1027 // helper function to copy the value from location addr to jvalue. 1028 static inline void copy_to_jvalue(jvalue *v, address addr, jvmtiPrimitiveType value_type) { 1029 switch (value_type) { 1030 case JVMTI_PRIMITIVE_TYPE_BOOLEAN : { v->z = *(jboolean*)addr; break; } 1031 case JVMTI_PRIMITIVE_TYPE_BYTE : { v->b = *(jbyte*)addr; break; } 1032 case JVMTI_PRIMITIVE_TYPE_CHAR : { v->c = *(jchar*)addr; break; } 1033 case JVMTI_PRIMITIVE_TYPE_SHORT : { v->s = *(jshort*)addr; break; } 1034 case JVMTI_PRIMITIVE_TYPE_INT : { v->i = *(jint*)addr; break; } 1035 case JVMTI_PRIMITIVE_TYPE_LONG : { v->j = *(jlong*)addr; break; } 1036 case JVMTI_PRIMITIVE_TYPE_FLOAT : { v->f = *(jfloat*)addr; break; } 1037 case JVMTI_PRIMITIVE_TYPE_DOUBLE : { v->d = *(jdouble*)addr; break; } 1038 default: ShouldNotReachHere(); 1039 } 1040 } 1041 1042 // helper function to invoke string primitive value callback 1043 // returns visit control flags 1044 static jint invoke_string_value_callback(jvmtiStringPrimitiveValueCallback cb, 1045 CallbackWrapper* wrapper, 1046 oop str, 1047 void* user_data) 1048 { 1049 assert(str->klass() == SystemDictionary::String_klass(), "not a string"); 1050 1051 // get the string value and length 1052 // (string value may be offset from the base) 1053 int s_len = java_lang_String::length(str); 1054 typeArrayOop s_value = java_lang_String::value(str); 1055 int s_offset = java_lang_String::offset(str); 1056 jchar* value; 1057 if (s_len > 0) { 1058 value = s_value->char_at_addr(s_offset); 1059 } else { 1060 value = (jchar*) s_value->base(T_CHAR); 1061 } 1062 1063 // invoke the callback 1064 return (*cb)(wrapper->klass_tag(), 1065 wrapper->obj_size(), 1066 wrapper->obj_tag_p(), 1067 value, 1068 (jint)s_len, 1069 user_data); 1070 } 1071 1072 // helper function to invoke string primitive value callback 1073 // returns visit control flags 1074 static jint invoke_array_primitive_value_callback(jvmtiArrayPrimitiveValueCallback cb, 1075 CallbackWrapper* wrapper, 1076 oop obj, 1077 void* user_data) 1078 { 1079 assert(obj->is_typeArray(), "not a primitive array"); 1080 1081 // get base address of first element 1082 typeArrayOop array = typeArrayOop(obj); 1083 BasicType type = TypeArrayKlass::cast(array->klass())->element_type(); 1084 void* elements = array->base(type); 1085 1086 // jvmtiPrimitiveType is defined so this mapping is always correct 1087 jvmtiPrimitiveType elem_type = (jvmtiPrimitiveType)type2char(type); 1088 1089 return (*cb)(wrapper->klass_tag(), 1090 wrapper->obj_size(), 1091 wrapper->obj_tag_p(), 1092 (jint)array->length(), 1093 elem_type, 1094 elements, 1095 user_data); 1096 } 1097 1098 // helper function to invoke the primitive field callback for all static fields 1099 // of a given class 1100 static jint invoke_primitive_field_callback_for_static_fields 1101 (CallbackWrapper* wrapper, 1102 oop obj, 1103 jvmtiPrimitiveFieldCallback cb, 1104 void* user_data) 1105 { 1106 // for static fields only the index will be set 1107 static jvmtiHeapReferenceInfo reference_info = { 0 }; 1108 1109 assert(obj->klass() == SystemDictionary::Class_klass(), "not a class"); 1110 if (java_lang_Class::is_primitive(obj)) { 1111 return 0; 1112 } 1113 Klass* klass = java_lang_Class::as_Klass(obj); 1114 1115 // ignore classes for object and type arrays 1116 if (!klass->oop_is_instance()) { 1117 return 0; 1118 } 1119 1120 // ignore classes which aren't linked yet 1121 InstanceKlass* ik = InstanceKlass::cast(klass); 1122 if (!ik->is_linked()) { 1123 return 0; 1124 } 1125 1126 // get the field map 1127 ClassFieldMap* field_map = ClassFieldMap::create_map_of_static_fields(klass); 1128 1129 // invoke the callback for each static primitive field 1130 for (int i=0; i<field_map->field_count(); i++) { 1131 ClassFieldDescriptor* field = field_map->field_at(i); 1132 1133 // ignore non-primitive fields 1134 char type = field->field_type(); 1135 if (!is_primitive_field_type(type)) { 1136 continue; 1137 } 1138 // one-to-one mapping 1139 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type; 1140 1141 // get offset and field value 1142 int offset = field->field_offset(); 1143 address addr = (address)klass->java_mirror() + offset; 1144 jvalue value; 1145 copy_to_jvalue(&value, addr, value_type); 1146 1147 // field index 1148 reference_info.field.index = field->field_index(); 1149 1150 // invoke the callback 1151 jint res = (*cb)(JVMTI_HEAP_REFERENCE_STATIC_FIELD, 1152 &reference_info, 1153 wrapper->klass_tag(), 1154 wrapper->obj_tag_p(), 1155 value, 1156 value_type, 1157 user_data); 1158 if (res & JVMTI_VISIT_ABORT) { 1159 delete field_map; 1160 return res; 1161 } 1162 } 1163 1164 delete field_map; 1165 return 0; 1166 } 1167 1168 // helper function to invoke the primitive field callback for all instance fields 1169 // of a given object 1170 static jint invoke_primitive_field_callback_for_instance_fields( 1171 CallbackWrapper* wrapper, 1172 oop obj, 1173 jvmtiPrimitiveFieldCallback cb, 1174 void* user_data) 1175 { 1176 // for instance fields only the index will be set 1177 static jvmtiHeapReferenceInfo reference_info = { 0 }; 1178 1179 // get the map of the instance fields 1180 ClassFieldMap* fields = JvmtiCachedClassFieldMap::get_map_of_instance_fields(obj); 1181 1182 // invoke the callback for each instance primitive field 1183 for (int i=0; i<fields->field_count(); i++) { 1184 ClassFieldDescriptor* field = fields->field_at(i); 1185 1186 // ignore non-primitive fields 1187 char type = field->field_type(); 1188 if (!is_primitive_field_type(type)) { 1189 continue; 1190 } 1191 // one-to-one mapping 1192 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type; 1193 1194 // get offset and field value 1195 int offset = field->field_offset(); 1196 address addr = (address)obj + offset; 1197 jvalue value; 1198 copy_to_jvalue(&value, addr, value_type); 1199 1200 // field index 1201 reference_info.field.index = field->field_index(); 1202 1203 // invoke the callback 1204 jint res = (*cb)(JVMTI_HEAP_REFERENCE_FIELD, 1205 &reference_info, 1206 wrapper->klass_tag(), 1207 wrapper->obj_tag_p(), 1208 value, 1209 value_type, 1210 user_data); 1211 if (res & JVMTI_VISIT_ABORT) { 1212 return res; 1213 } 1214 } 1215 return 0; 1216 } 1217 1218 1219 // VM operation to iterate over all objects in the heap (both reachable 1220 // and unreachable) 1221 class VM_HeapIterateOperation: public VM_Operation { 1222 private: 1223 ObjectClosure* _blk; 1224 public: 1225 VM_HeapIterateOperation(ObjectClosure* blk) { _blk = blk; } 1226 1227 VMOp_Type type() const { return VMOp_HeapIterateOperation; } 1228 void doit() { 1229 // allows class files maps to be cached during iteration 1230 ClassFieldMapCacheMark cm; 1231 1232 // make sure that heap is parsable (fills TLABs with filler objects) 1233 Universe::heap()->ensure_parsability(false); // no need to retire TLABs 1234 1235 // Verify heap before iteration - if the heap gets corrupted then 1236 // JVMTI's IterateOverHeap will crash. 1237 if (VerifyBeforeIteration) { 1238 Universe::verify(); 1239 } 1240 1241 // do the iteration 1242 // If this operation encounters a bad object when using CMS, 1243 // consider using safe_object_iterate() which avoids perm gen 1244 // objects that may contain bad references. 1245 Universe::heap()->object_iterate(_blk); 1246 } 1247 1248 }; 1249 1250 1251 // An ObjectClosure used to support the deprecated IterateOverHeap and 1252 // IterateOverInstancesOfClass functions 1253 class IterateOverHeapObjectClosure: public ObjectClosure { 1254 private: 1255 JvmtiTagMap* _tag_map; 1256 KlassHandle _klass; 1257 jvmtiHeapObjectFilter _object_filter; 1258 jvmtiHeapObjectCallback _heap_object_callback; 1259 const void* _user_data; 1260 1261 // accessors 1262 JvmtiTagMap* tag_map() const { return _tag_map; } 1263 jvmtiHeapObjectFilter object_filter() const { return _object_filter; } 1264 jvmtiHeapObjectCallback object_callback() const { return _heap_object_callback; } 1265 KlassHandle klass() const { return _klass; } 1266 const void* user_data() const { return _user_data; } 1267 1268 // indicates if iteration has been aborted 1269 bool _iteration_aborted; 1270 bool is_iteration_aborted() const { return _iteration_aborted; } 1271 void set_iteration_aborted(bool aborted) { _iteration_aborted = aborted; } 1272 1273 public: 1274 IterateOverHeapObjectClosure(JvmtiTagMap* tag_map, 1275 KlassHandle klass, 1276 jvmtiHeapObjectFilter object_filter, 1277 jvmtiHeapObjectCallback heap_object_callback, 1278 const void* user_data) : 1279 _tag_map(tag_map), 1280 _klass(klass), 1281 _object_filter(object_filter), 1282 _heap_object_callback(heap_object_callback), 1283 _user_data(user_data), 1284 _iteration_aborted(false) 1285 { 1286 } 1287 1288 void do_object(oop o); 1289 }; 1290 1291 // invoked for each object in the heap 1292 void IterateOverHeapObjectClosure::do_object(oop o) { 1293 // check if iteration has been halted 1294 if (is_iteration_aborted()) return; 1295 1296 // ignore any objects that aren't visible to profiler 1297 if (!ServiceUtil::visible_oop(o)) return; 1298 1299 // instanceof check when filtering by klass 1300 if (!klass().is_null() && !o->is_a(klass()())) { 1301 return; 1302 } 1303 // prepare for the calllback 1304 CallbackWrapper wrapper(tag_map(), o); 1305 1306 // if the object is tagged and we're only interested in untagged objects 1307 // then don't invoke the callback. Similiarly, if the object is untagged 1308 // and we're only interested in tagged objects we skip the callback. 1309 if (wrapper.obj_tag() != 0) { 1310 if (object_filter() == JVMTI_HEAP_OBJECT_UNTAGGED) return; 1311 } else { 1312 if (object_filter() == JVMTI_HEAP_OBJECT_TAGGED) return; 1313 } 1314 1315 // invoke the agent's callback 1316 jvmtiIterationControl control = (*object_callback())(wrapper.klass_tag(), 1317 wrapper.obj_size(), 1318 wrapper.obj_tag_p(), 1319 (void*)user_data()); 1320 if (control == JVMTI_ITERATION_ABORT) { 1321 set_iteration_aborted(true); 1322 } 1323 } 1324 1325 // An ObjectClosure used to support the IterateThroughHeap function 1326 class IterateThroughHeapObjectClosure: public ObjectClosure { 1327 private: 1328 JvmtiTagMap* _tag_map; 1329 KlassHandle _klass; 1330 int _heap_filter; 1331 const jvmtiHeapCallbacks* _callbacks; 1332 const void* _user_data; 1333 1334 // accessor functions 1335 JvmtiTagMap* tag_map() const { return _tag_map; } 1336 int heap_filter() const { return _heap_filter; } 1337 const jvmtiHeapCallbacks* callbacks() const { return _callbacks; } 1338 KlassHandle klass() const { return _klass; } 1339 const void* user_data() const { return _user_data; } 1340 1341 // indicates if the iteration has been aborted 1342 bool _iteration_aborted; 1343 bool is_iteration_aborted() const { return _iteration_aborted; } 1344 1345 // used to check the visit control flags. If the abort flag is set 1346 // then we set the iteration aborted flag so that the iteration completes 1347 // without processing any further objects 1348 bool check_flags_for_abort(jint flags) { 1349 bool is_abort = (flags & JVMTI_VISIT_ABORT) != 0; 1350 if (is_abort) { 1351 _iteration_aborted = true; 1352 } 1353 return is_abort; 1354 } 1355 1356 public: 1357 IterateThroughHeapObjectClosure(JvmtiTagMap* tag_map, 1358 KlassHandle klass, 1359 int heap_filter, 1360 const jvmtiHeapCallbacks* heap_callbacks, 1361 const void* user_data) : 1362 _tag_map(tag_map), 1363 _klass(klass), 1364 _heap_filter(heap_filter), 1365 _callbacks(heap_callbacks), 1366 _user_data(user_data), 1367 _iteration_aborted(false) 1368 { 1369 } 1370 1371 void do_object(oop o); 1372 }; 1373 1374 // invoked for each object in the heap 1375 void IterateThroughHeapObjectClosure::do_object(oop obj) { 1376 // check if iteration has been halted 1377 if (is_iteration_aborted()) return; 1378 1379 // ignore any objects that aren't visible to profiler 1380 if (!ServiceUtil::visible_oop(obj)) return; 1381 1382 // apply class filter 1383 if (is_filtered_by_klass_filter(obj, klass())) return; 1384 1385 // prepare for callback 1386 CallbackWrapper wrapper(tag_map(), obj); 1387 1388 // check if filtered by the heap filter 1389 if (is_filtered_by_heap_filter(wrapper.obj_tag(), wrapper.klass_tag(), heap_filter())) { 1390 return; 1391 } 1392 1393 // for arrays we need the length, otherwise -1 1394 bool is_array = obj->is_array(); 1395 int len = is_array ? arrayOop(obj)->length() : -1; 1396 1397 // invoke the object callback (if callback is provided) 1398 if (callbacks()->heap_iteration_callback != NULL) { 1399 jvmtiHeapIterationCallback cb = callbacks()->heap_iteration_callback; 1400 jint res = (*cb)(wrapper.klass_tag(), 1401 wrapper.obj_size(), 1402 wrapper.obj_tag_p(), 1403 (jint)len, 1404 (void*)user_data()); 1405 if (check_flags_for_abort(res)) return; 1406 } 1407 1408 // for objects and classes we report primitive fields if callback provided 1409 if (callbacks()->primitive_field_callback != NULL && obj->is_instance()) { 1410 jint res; 1411 jvmtiPrimitiveFieldCallback cb = callbacks()->primitive_field_callback; 1412 if (obj->klass() == SystemDictionary::Class_klass()) { 1413 res = invoke_primitive_field_callback_for_static_fields(&wrapper, 1414 obj, 1415 cb, 1416 (void*)user_data()); 1417 } else { 1418 res = invoke_primitive_field_callback_for_instance_fields(&wrapper, 1419 obj, 1420 cb, 1421 (void*)user_data()); 1422 } 1423 if (check_flags_for_abort(res)) return; 1424 } 1425 1426 // string callback 1427 if (!is_array && 1428 callbacks()->string_primitive_value_callback != NULL && 1429 obj->klass() == SystemDictionary::String_klass()) { 1430 jint res = invoke_string_value_callback( 1431 callbacks()->string_primitive_value_callback, 1432 &wrapper, 1433 obj, 1434 (void*)user_data() ); 1435 if (check_flags_for_abort(res)) return; 1436 } 1437 1438 // array callback 1439 if (is_array && 1440 callbacks()->array_primitive_value_callback != NULL && 1441 obj->is_typeArray()) { 1442 jint res = invoke_array_primitive_value_callback( 1443 callbacks()->array_primitive_value_callback, 1444 &wrapper, 1445 obj, 1446 (void*)user_data() ); 1447 if (check_flags_for_abort(res)) return; 1448 } 1449 }; 1450 1451 1452 // Deprecated function to iterate over all objects in the heap 1453 void JvmtiTagMap::iterate_over_heap(jvmtiHeapObjectFilter object_filter, 1454 KlassHandle klass, 1455 jvmtiHeapObjectCallback heap_object_callback, 1456 const void* user_data) 1457 { 1458 MutexLocker ml(Heap_lock); 1459 IterateOverHeapObjectClosure blk(this, 1460 klass, 1461 object_filter, 1462 heap_object_callback, 1463 user_data); 1464 VM_HeapIterateOperation op(&blk); 1465 VMThread::execute(&op); 1466 } 1467 1468 1469 // Iterates over all objects in the heap 1470 void JvmtiTagMap::iterate_through_heap(jint heap_filter, 1471 KlassHandle klass, 1472 const jvmtiHeapCallbacks* callbacks, 1473 const void* user_data) 1474 { 1475 MutexLocker ml(Heap_lock); 1476 IterateThroughHeapObjectClosure blk(this, 1477 klass, 1478 heap_filter, 1479 callbacks, 1480 user_data); 1481 VM_HeapIterateOperation op(&blk); 1482 VMThread::execute(&op); 1483 } 1484 1485 // support class for get_objects_with_tags 1486 1487 class TagObjectCollector : public JvmtiTagHashmapEntryClosure { 1488 private: 1489 JvmtiEnv* _env; 1490 jlong* _tags; 1491 jint _tag_count; 1492 1493 GrowableArray<jobject>* _object_results; // collected objects (JNI weak refs) 1494 GrowableArray<uint64_t>* _tag_results; // collected tags 1495 1496 public: 1497 TagObjectCollector(JvmtiEnv* env, const jlong* tags, jint tag_count) { 1498 _env = env; 1499 _tags = (jlong*)tags; 1500 _tag_count = tag_count; 1501 _object_results = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<jobject>(1,true); 1502 _tag_results = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<uint64_t>(1,true); 1503 } 1504 1505 ~TagObjectCollector() { 1506 delete _object_results; 1507 delete _tag_results; 1508 } 1509 1510 // for each tagged object check if the tag value matches 1511 // - if it matches then we create a JNI local reference to the object 1512 // and record the reference and tag value. 1513 // 1514 void do_entry(JvmtiTagHashmapEntry* entry) { 1515 for (int i=0; i<_tag_count; i++) { 1516 if (_tags[i] == entry->tag()) { 1517 oop o = entry->object(); 1518 assert(o != NULL && Universe::heap()->is_in_reserved(o), "sanity check"); 1519 jobject ref = JNIHandles::make_local(JavaThread::current(), o); 1520 _object_results->append(ref); 1521 _tag_results->append((uint64_t)entry->tag()); 1522 } 1523 } 1524 } 1525 1526 // return the results from the collection 1527 // 1528 jvmtiError result(jint* count_ptr, jobject** object_result_ptr, jlong** tag_result_ptr) { 1529 jvmtiError error; 1530 int count = _object_results->length(); 1531 assert(count >= 0, "sanity check"); 1532 1533 // if object_result_ptr is not NULL then allocate the result and copy 1534 // in the object references. 1535 if (object_result_ptr != NULL) { 1536 error = _env->Allocate(count * sizeof(jobject), (unsigned char**)object_result_ptr); 1537 if (error != JVMTI_ERROR_NONE) { 1538 return error; 1539 } 1540 for (int i=0; i<count; i++) { 1541 (*object_result_ptr)[i] = _object_results->at(i); 1542 } 1543 } 1544 1545 // if tag_result_ptr is not NULL then allocate the result and copy 1546 // in the tag values. 1547 if (tag_result_ptr != NULL) { 1548 error = _env->Allocate(count * sizeof(jlong), (unsigned char**)tag_result_ptr); 1549 if (error != JVMTI_ERROR_NONE) { 1550 if (object_result_ptr != NULL) { 1551 _env->Deallocate((unsigned char*)object_result_ptr); 1552 } 1553 return error; 1554 } 1555 for (int i=0; i<count; i++) { 1556 (*tag_result_ptr)[i] = (jlong)_tag_results->at(i); 1557 } 1558 } 1559 1560 *count_ptr = count; 1561 return JVMTI_ERROR_NONE; 1562 } 1563 }; 1564 1565 // return the list of objects with the specified tags 1566 jvmtiError JvmtiTagMap::get_objects_with_tags(const jlong* tags, 1567 jint count, jint* count_ptr, jobject** object_result_ptr, jlong** tag_result_ptr) { 1568 1569 TagObjectCollector collector(env(), tags, count); 1570 { 1571 // iterate over all tagged objects 1572 MutexLocker ml(lock()); 1573 entry_iterate(&collector); 1574 } 1575 return collector.result(count_ptr, object_result_ptr, tag_result_ptr); 1576 } 1577 1578 1579 // ObjectMarker is used to support the marking objects when walking the 1580 // heap. 1581 // 1582 // This implementation uses the existing mark bits in an object for 1583 // marking. Objects that are marked must later have their headers restored. 1584 // As most objects are unlocked and don't have their identity hash computed 1585 // we don't have to save their headers. Instead we save the headers that 1586 // are "interesting". Later when the headers are restored this implementation 1587 // restores all headers to their initial value and then restores the few 1588 // objects that had interesting headers. 1589 // 1590 // Future work: This implementation currently uses growable arrays to save 1591 // the oop and header of interesting objects. As an optimization we could 1592 // use the same technique as the GC and make use of the unused area 1593 // between top() and end(). 1594 // 1595 1596 // An ObjectClosure used to restore the mark bits of an object 1597 class RestoreMarksClosure : public ObjectClosure { 1598 public: 1599 void do_object(oop o) { 1600 if (o != NULL) { 1601 markOop mark = o->mark(); 1602 if (mark->is_marked()) { 1603 o->init_mark(); 1604 } 1605 } 1606 } 1607 }; 1608 1609 // ObjectMarker provides the mark and visited functions 1610 class ObjectMarker : AllStatic { 1611 private: 1612 // saved headers 1613 static GrowableArray<oop>* _saved_oop_stack; 1614 static GrowableArray<markOop>* _saved_mark_stack; 1615 static bool _needs_reset; // do we need to reset mark bits? 1616 1617 public: 1618 static void init(); // initialize 1619 static void done(); // clean-up 1620 1621 static inline void mark(oop o); // mark an object 1622 static inline bool visited(oop o); // check if object has been visited 1623 1624 static inline bool needs_reset() { return _needs_reset; } 1625 static inline void set_needs_reset(bool v) { _needs_reset = v; } 1626 }; 1627 1628 GrowableArray<oop>* ObjectMarker::_saved_oop_stack = NULL; 1629 GrowableArray<markOop>* ObjectMarker::_saved_mark_stack = NULL; 1630 bool ObjectMarker::_needs_reset = true; // need to reset mark bits by default 1631 1632 // initialize ObjectMarker - prepares for object marking 1633 void ObjectMarker::init() { 1634 assert(Thread::current()->is_VM_thread(), "must be VMThread"); 1635 1636 // prepare heap for iteration 1637 Universe::heap()->ensure_parsability(false); // no need to retire TLABs 1638 1639 // create stacks for interesting headers 1640 _saved_mark_stack = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<markOop>(4000, true); 1641 _saved_oop_stack = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(4000, true); 1642 1643 if (UseBiasedLocking) { 1644 BiasedLocking::preserve_marks(); 1645 } 1646 } 1647 1648 // Object marking is done so restore object headers 1649 void ObjectMarker::done() { 1650 // iterate over all objects and restore the mark bits to 1651 // their initial value 1652 RestoreMarksClosure blk; 1653 if (needs_reset()) { 1654 Universe::heap()->object_iterate(&blk); 1655 } else { 1656 // We don't need to reset mark bits on this call, but reset the 1657 // flag to the default for the next call. 1658 set_needs_reset(true); 1659 } 1660 1661 // now restore the interesting headers 1662 for (int i = 0; i < _saved_oop_stack->length(); i++) { 1663 oop o = _saved_oop_stack->at(i); 1664 markOop mark = _saved_mark_stack->at(i); 1665 o->set_mark(mark); 1666 } 1667 1668 if (UseBiasedLocking) { 1669 BiasedLocking::restore_marks(); 1670 } 1671 1672 // free the stacks 1673 delete _saved_oop_stack; 1674 delete _saved_mark_stack; 1675 } 1676 1677 // mark an object 1678 inline void ObjectMarker::mark(oop o) { 1679 assert(Universe::heap()->is_in(o), "sanity check"); 1680 assert(!o->mark()->is_marked(), "should only mark an object once"); 1681 1682 // object's mark word 1683 markOop mark = o->mark(); 1684 1685 if (mark->must_be_preserved(o)) { 1686 _saved_mark_stack->push(mark); 1687 _saved_oop_stack->push(o); 1688 } 1689 1690 // mark the object 1691 o->set_mark(markOopDesc::prototype()->set_marked()); 1692 } 1693 1694 // return true if object is marked 1695 inline bool ObjectMarker::visited(oop o) { 1696 return o->mark()->is_marked(); 1697 } 1698 1699 // Stack allocated class to help ensure that ObjectMarker is used 1700 // correctly. Constructor initializes ObjectMarker, destructor calls 1701 // ObjectMarker's done() function to restore object headers. 1702 class ObjectMarkerController : public StackObj { 1703 public: 1704 ObjectMarkerController() { 1705 ObjectMarker::init(); 1706 } 1707 ~ObjectMarkerController() { 1708 ObjectMarker::done(); 1709 } 1710 }; 1711 1712 1713 // helper to map a jvmtiHeapReferenceKind to an old style jvmtiHeapRootKind 1714 // (not performance critical as only used for roots) 1715 static jvmtiHeapRootKind toJvmtiHeapRootKind(jvmtiHeapReferenceKind kind) { 1716 switch (kind) { 1717 case JVMTI_HEAP_REFERENCE_JNI_GLOBAL: return JVMTI_HEAP_ROOT_JNI_GLOBAL; 1718 case JVMTI_HEAP_REFERENCE_SYSTEM_CLASS: return JVMTI_HEAP_ROOT_SYSTEM_CLASS; 1719 case JVMTI_HEAP_REFERENCE_MONITOR: return JVMTI_HEAP_ROOT_MONITOR; 1720 case JVMTI_HEAP_REFERENCE_STACK_LOCAL: return JVMTI_HEAP_ROOT_STACK_LOCAL; 1721 case JVMTI_HEAP_REFERENCE_JNI_LOCAL: return JVMTI_HEAP_ROOT_JNI_LOCAL; 1722 case JVMTI_HEAP_REFERENCE_THREAD: return JVMTI_HEAP_ROOT_THREAD; 1723 case JVMTI_HEAP_REFERENCE_OTHER: return JVMTI_HEAP_ROOT_OTHER; 1724 default: ShouldNotReachHere(); return JVMTI_HEAP_ROOT_OTHER; 1725 } 1726 } 1727 1728 // Base class for all heap walk contexts. The base class maintains a flag 1729 // to indicate if the context is valid or not. 1730 class HeapWalkContext VALUE_OBJ_CLASS_SPEC { 1731 private: 1732 bool _valid; 1733 public: 1734 HeapWalkContext(bool valid) { _valid = valid; } 1735 void invalidate() { _valid = false; } 1736 bool is_valid() const { return _valid; } 1737 }; 1738 1739 // A basic heap walk context for the deprecated heap walking functions. 1740 // The context for a basic heap walk are the callbacks and fields used by 1741 // the referrer caching scheme. 1742 class BasicHeapWalkContext: public HeapWalkContext { 1743 private: 1744 jvmtiHeapRootCallback _heap_root_callback; 1745 jvmtiStackReferenceCallback _stack_ref_callback; 1746 jvmtiObjectReferenceCallback _object_ref_callback; 1747 1748 // used for caching 1749 oop _last_referrer; 1750 jlong _last_referrer_tag; 1751 1752 public: 1753 BasicHeapWalkContext() : HeapWalkContext(false) { } 1754 1755 BasicHeapWalkContext(jvmtiHeapRootCallback heap_root_callback, 1756 jvmtiStackReferenceCallback stack_ref_callback, 1757 jvmtiObjectReferenceCallback object_ref_callback) : 1758 HeapWalkContext(true), 1759 _heap_root_callback(heap_root_callback), 1760 _stack_ref_callback(stack_ref_callback), 1761 _object_ref_callback(object_ref_callback), 1762 _last_referrer(NULL), 1763 _last_referrer_tag(0) { 1764 } 1765 1766 // accessors 1767 jvmtiHeapRootCallback heap_root_callback() const { return _heap_root_callback; } 1768 jvmtiStackReferenceCallback stack_ref_callback() const { return _stack_ref_callback; } 1769 jvmtiObjectReferenceCallback object_ref_callback() const { return _object_ref_callback; } 1770 1771 oop last_referrer() const { return _last_referrer; } 1772 void set_last_referrer(oop referrer) { _last_referrer = referrer; } 1773 jlong last_referrer_tag() const { return _last_referrer_tag; } 1774 void set_last_referrer_tag(jlong value) { _last_referrer_tag = value; } 1775 }; 1776 1777 // The advanced heap walk context for the FollowReferences functions. 1778 // The context is the callbacks, and the fields used for filtering. 1779 class AdvancedHeapWalkContext: public HeapWalkContext { 1780 private: 1781 jint _heap_filter; 1782 KlassHandle _klass_filter; 1783 const jvmtiHeapCallbacks* _heap_callbacks; 1784 1785 public: 1786 AdvancedHeapWalkContext() : HeapWalkContext(false) { } 1787 1788 AdvancedHeapWalkContext(jint heap_filter, 1789 KlassHandle klass_filter, 1790 const jvmtiHeapCallbacks* heap_callbacks) : 1791 HeapWalkContext(true), 1792 _heap_filter(heap_filter), 1793 _klass_filter(klass_filter), 1794 _heap_callbacks(heap_callbacks) { 1795 } 1796 1797 // accessors 1798 jint heap_filter() const { return _heap_filter; } 1799 KlassHandle klass_filter() const { return _klass_filter; } 1800 1801 const jvmtiHeapReferenceCallback heap_reference_callback() const { 1802 return _heap_callbacks->heap_reference_callback; 1803 }; 1804 const jvmtiPrimitiveFieldCallback primitive_field_callback() const { 1805 return _heap_callbacks->primitive_field_callback; 1806 } 1807 const jvmtiArrayPrimitiveValueCallback array_primitive_value_callback() const { 1808 return _heap_callbacks->array_primitive_value_callback; 1809 } 1810 const jvmtiStringPrimitiveValueCallback string_primitive_value_callback() const { 1811 return _heap_callbacks->string_primitive_value_callback; 1812 } 1813 }; 1814 1815 // The CallbackInvoker is a class with static functions that the heap walk can call 1816 // into to invoke callbacks. It works in one of two modes. The "basic" mode is 1817 // used for the deprecated IterateOverReachableObjects functions. The "advanced" 1818 // mode is for the newer FollowReferences function which supports a lot of 1819 // additional callbacks. 1820 class CallbackInvoker : AllStatic { 1821 private: 1822 // heap walk styles 1823 enum { basic, advanced }; 1824 static int _heap_walk_type; 1825 static bool is_basic_heap_walk() { return _heap_walk_type == basic; } 1826 static bool is_advanced_heap_walk() { return _heap_walk_type == advanced; } 1827 1828 // context for basic style heap walk 1829 static BasicHeapWalkContext _basic_context; 1830 static BasicHeapWalkContext* basic_context() { 1831 assert(_basic_context.is_valid(), "invalid"); 1832 return &_basic_context; 1833 } 1834 1835 // context for advanced style heap walk 1836 static AdvancedHeapWalkContext _advanced_context; 1837 static AdvancedHeapWalkContext* advanced_context() { 1838 assert(_advanced_context.is_valid(), "invalid"); 1839 return &_advanced_context; 1840 } 1841 1842 // context needed for all heap walks 1843 static JvmtiTagMap* _tag_map; 1844 static const void* _user_data; 1845 static GrowableArray<oop>* _visit_stack; 1846 1847 // accessors 1848 static JvmtiTagMap* tag_map() { return _tag_map; } 1849 static const void* user_data() { return _user_data; } 1850 static GrowableArray<oop>* visit_stack() { return _visit_stack; } 1851 1852 // if the object hasn't been visited then push it onto the visit stack 1853 // so that it will be visited later 1854 static inline bool check_for_visit(oop obj) { 1855 if (!ObjectMarker::visited(obj)) visit_stack()->push(obj); 1856 return true; 1857 } 1858 1859 // invoke basic style callbacks 1860 static inline bool invoke_basic_heap_root_callback 1861 (jvmtiHeapRootKind root_kind, oop obj); 1862 static inline bool invoke_basic_stack_ref_callback 1863 (jvmtiHeapRootKind root_kind, jlong thread_tag, jint depth, jmethodID method, 1864 int slot, oop obj); 1865 static inline bool invoke_basic_object_reference_callback 1866 (jvmtiObjectReferenceKind ref_kind, oop referrer, oop referree, jint index); 1867 1868 // invoke advanced style callbacks 1869 static inline bool invoke_advanced_heap_root_callback 1870 (jvmtiHeapReferenceKind ref_kind, oop obj); 1871 static inline bool invoke_advanced_stack_ref_callback 1872 (jvmtiHeapReferenceKind ref_kind, jlong thread_tag, jlong tid, int depth, 1873 jmethodID method, jlocation bci, jint slot, oop obj); 1874 static inline bool invoke_advanced_object_reference_callback 1875 (jvmtiHeapReferenceKind ref_kind, oop referrer, oop referree, jint index); 1876 1877 // used to report the value of primitive fields 1878 static inline bool report_primitive_field 1879 (jvmtiHeapReferenceKind ref_kind, oop obj, jint index, address addr, char type); 1880 1881 public: 1882 // initialize for basic mode 1883 static void initialize_for_basic_heap_walk(JvmtiTagMap* tag_map, 1884 GrowableArray<oop>* visit_stack, 1885 const void* user_data, 1886 BasicHeapWalkContext context); 1887 1888 // initialize for advanced mode 1889 static void initialize_for_advanced_heap_walk(JvmtiTagMap* tag_map, 1890 GrowableArray<oop>* visit_stack, 1891 const void* user_data, 1892 AdvancedHeapWalkContext context); 1893 1894 // functions to report roots 1895 static inline bool report_simple_root(jvmtiHeapReferenceKind kind, oop o); 1896 static inline bool report_jni_local_root(jlong thread_tag, jlong tid, jint depth, 1897 jmethodID m, oop o); 1898 static inline bool report_stack_ref_root(jlong thread_tag, jlong tid, jint depth, 1899 jmethodID method, jlocation bci, jint slot, oop o); 1900 1901 // functions to report references 1902 static inline bool report_array_element_reference(oop referrer, oop referree, jint index); 1903 static inline bool report_class_reference(oop referrer, oop referree); 1904 static inline bool report_class_loader_reference(oop referrer, oop referree); 1905 static inline bool report_signers_reference(oop referrer, oop referree); 1906 static inline bool report_protection_domain_reference(oop referrer, oop referree); 1907 static inline bool report_superclass_reference(oop referrer, oop referree); 1908 static inline bool report_interface_reference(oop referrer, oop referree); 1909 static inline bool report_static_field_reference(oop referrer, oop referree, jint slot); 1910 static inline bool report_field_reference(oop referrer, oop referree, jint slot); 1911 static inline bool report_constant_pool_reference(oop referrer, oop referree, jint index); 1912 static inline bool report_primitive_array_values(oop array); 1913 static inline bool report_string_value(oop str); 1914 static inline bool report_primitive_instance_field(oop o, jint index, address value, char type); 1915 static inline bool report_primitive_static_field(oop o, jint index, address value, char type); 1916 }; 1917 1918 // statics 1919 int CallbackInvoker::_heap_walk_type; 1920 BasicHeapWalkContext CallbackInvoker::_basic_context; 1921 AdvancedHeapWalkContext CallbackInvoker::_advanced_context; 1922 JvmtiTagMap* CallbackInvoker::_tag_map; 1923 const void* CallbackInvoker::_user_data; 1924 GrowableArray<oop>* CallbackInvoker::_visit_stack; 1925 1926 // initialize for basic heap walk (IterateOverReachableObjects et al) 1927 void CallbackInvoker::initialize_for_basic_heap_walk(JvmtiTagMap* tag_map, 1928 GrowableArray<oop>* visit_stack, 1929 const void* user_data, 1930 BasicHeapWalkContext context) { 1931 _tag_map = tag_map; 1932 _visit_stack = visit_stack; 1933 _user_data = user_data; 1934 _basic_context = context; 1935 _advanced_context.invalidate(); // will trigger assertion if used 1936 _heap_walk_type = basic; 1937 } 1938 1939 // initialize for advanced heap walk (FollowReferences) 1940 void CallbackInvoker::initialize_for_advanced_heap_walk(JvmtiTagMap* tag_map, 1941 GrowableArray<oop>* visit_stack, 1942 const void* user_data, 1943 AdvancedHeapWalkContext context) { 1944 _tag_map = tag_map; 1945 _visit_stack = visit_stack; 1946 _user_data = user_data; 1947 _advanced_context = context; 1948 _basic_context.invalidate(); // will trigger assertion if used 1949 _heap_walk_type = advanced; 1950 } 1951 1952 1953 // invoke basic style heap root callback 1954 inline bool CallbackInvoker::invoke_basic_heap_root_callback(jvmtiHeapRootKind root_kind, oop obj) { 1955 assert(ServiceUtil::visible_oop(obj), "checking"); 1956 1957 // if we heap roots should be reported 1958 jvmtiHeapRootCallback cb = basic_context()->heap_root_callback(); 1959 if (cb == NULL) { 1960 return check_for_visit(obj); 1961 } 1962 1963 CallbackWrapper wrapper(tag_map(), obj); 1964 jvmtiIterationControl control = (*cb)(root_kind, 1965 wrapper.klass_tag(), 1966 wrapper.obj_size(), 1967 wrapper.obj_tag_p(), 1968 (void*)user_data()); 1969 // push root to visit stack when following references 1970 if (control == JVMTI_ITERATION_CONTINUE && 1971 basic_context()->object_ref_callback() != NULL) { 1972 visit_stack()->push(obj); 1973 } 1974 return control != JVMTI_ITERATION_ABORT; 1975 } 1976 1977 // invoke basic style stack ref callback 1978 inline bool CallbackInvoker::invoke_basic_stack_ref_callback(jvmtiHeapRootKind root_kind, 1979 jlong thread_tag, 1980 jint depth, 1981 jmethodID method, 1982 jint slot, 1983 oop obj) { 1984 assert(ServiceUtil::visible_oop(obj), "checking"); 1985 1986 // if we stack refs should be reported 1987 jvmtiStackReferenceCallback cb = basic_context()->stack_ref_callback(); 1988 if (cb == NULL) { 1989 return check_for_visit(obj); 1990 } 1991 1992 CallbackWrapper wrapper(tag_map(), obj); 1993 jvmtiIterationControl control = (*cb)(root_kind, 1994 wrapper.klass_tag(), 1995 wrapper.obj_size(), 1996 wrapper.obj_tag_p(), 1997 thread_tag, 1998 depth, 1999 method, 2000 slot, 2001 (void*)user_data()); 2002 // push root to visit stack when following references 2003 if (control == JVMTI_ITERATION_CONTINUE && 2004 basic_context()->object_ref_callback() != NULL) { 2005 visit_stack()->push(obj); 2006 } 2007 return control != JVMTI_ITERATION_ABORT; 2008 } 2009 2010 // invoke basic style object reference callback 2011 inline bool CallbackInvoker::invoke_basic_object_reference_callback(jvmtiObjectReferenceKind ref_kind, 2012 oop referrer, 2013 oop referree, 2014 jint index) { 2015 2016 assert(ServiceUtil::visible_oop(referrer), "checking"); 2017 assert(ServiceUtil::visible_oop(referree), "checking"); 2018 2019 BasicHeapWalkContext* context = basic_context(); 2020 2021 // callback requires the referrer's tag. If it's the same referrer 2022 // as the last call then we use the cached value. 2023 jlong referrer_tag; 2024 if (referrer == context->last_referrer()) { 2025 referrer_tag = context->last_referrer_tag(); 2026 } else { 2027 referrer_tag = tag_for(tag_map(), referrer); 2028 } 2029 2030 // do the callback 2031 CallbackWrapper wrapper(tag_map(), referree); 2032 jvmtiObjectReferenceCallback cb = context->object_ref_callback(); 2033 jvmtiIterationControl control = (*cb)(ref_kind, 2034 wrapper.klass_tag(), 2035 wrapper.obj_size(), 2036 wrapper.obj_tag_p(), 2037 referrer_tag, 2038 index, 2039 (void*)user_data()); 2040 2041 // record referrer and referrer tag. For self-references record the 2042 // tag value from the callback as this might differ from referrer_tag. 2043 context->set_last_referrer(referrer); 2044 if (referrer == referree) { 2045 context->set_last_referrer_tag(*wrapper.obj_tag_p()); 2046 } else { 2047 context->set_last_referrer_tag(referrer_tag); 2048 } 2049 2050 if (control == JVMTI_ITERATION_CONTINUE) { 2051 return check_for_visit(referree); 2052 } else { 2053 return control != JVMTI_ITERATION_ABORT; 2054 } 2055 } 2056 2057 // invoke advanced style heap root callback 2058 inline bool CallbackInvoker::invoke_advanced_heap_root_callback(jvmtiHeapReferenceKind ref_kind, 2059 oop obj) { 2060 assert(ServiceUtil::visible_oop(obj), "checking"); 2061 2062 AdvancedHeapWalkContext* context = advanced_context(); 2063 2064 // check that callback is provided 2065 jvmtiHeapReferenceCallback cb = context->heap_reference_callback(); 2066 if (cb == NULL) { 2067 return check_for_visit(obj); 2068 } 2069 2070 // apply class filter 2071 if (is_filtered_by_klass_filter(obj, context->klass_filter())) { 2072 return check_for_visit(obj); 2073 } 2074 2075 // setup the callback wrapper 2076 CallbackWrapper wrapper(tag_map(), obj); 2077 2078 // apply tag filter 2079 if (is_filtered_by_heap_filter(wrapper.obj_tag(), 2080 wrapper.klass_tag(), 2081 context->heap_filter())) { 2082 return check_for_visit(obj); 2083 } 2084 2085 // for arrays we need the length, otherwise -1 2086 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1); 2087 2088 // invoke the callback 2089 jint res = (*cb)(ref_kind, 2090 NULL, // referrer info 2091 wrapper.klass_tag(), 2092 0, // referrer_class_tag is 0 for heap root 2093 wrapper.obj_size(), 2094 wrapper.obj_tag_p(), 2095 NULL, // referrer_tag_p 2096 len, 2097 (void*)user_data()); 2098 if (res & JVMTI_VISIT_ABORT) { 2099 return false;// referrer class tag 2100 } 2101 if (res & JVMTI_VISIT_OBJECTS) { 2102 check_for_visit(obj); 2103 } 2104 return true; 2105 } 2106 2107 // report a reference from a thread stack to an object 2108 inline bool CallbackInvoker::invoke_advanced_stack_ref_callback(jvmtiHeapReferenceKind ref_kind, 2109 jlong thread_tag, 2110 jlong tid, 2111 int depth, 2112 jmethodID method, 2113 jlocation bci, 2114 jint slot, 2115 oop obj) { 2116 assert(ServiceUtil::visible_oop(obj), "checking"); 2117 2118 AdvancedHeapWalkContext* context = advanced_context(); 2119 2120 // check that callback is provider 2121 jvmtiHeapReferenceCallback cb = context->heap_reference_callback(); 2122 if (cb == NULL) { 2123 return check_for_visit(obj); 2124 } 2125 2126 // apply class filter 2127 if (is_filtered_by_klass_filter(obj, context->klass_filter())) { 2128 return check_for_visit(obj); 2129 } 2130 2131 // setup the callback wrapper 2132 CallbackWrapper wrapper(tag_map(), obj); 2133 2134 // apply tag filter 2135 if (is_filtered_by_heap_filter(wrapper.obj_tag(), 2136 wrapper.klass_tag(), 2137 context->heap_filter())) { 2138 return check_for_visit(obj); 2139 } 2140 2141 // setup the referrer info 2142 jvmtiHeapReferenceInfo reference_info; 2143 reference_info.stack_local.thread_tag = thread_tag; 2144 reference_info.stack_local.thread_id = tid; 2145 reference_info.stack_local.depth = depth; 2146 reference_info.stack_local.method = method; 2147 reference_info.stack_local.location = bci; 2148 reference_info.stack_local.slot = slot; 2149 2150 // for arrays we need the length, otherwise -1 2151 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1); 2152 2153 // call into the agent 2154 int res = (*cb)(ref_kind, 2155 &reference_info, 2156 wrapper.klass_tag(), 2157 0, // referrer_class_tag is 0 for heap root (stack) 2158 wrapper.obj_size(), 2159 wrapper.obj_tag_p(), 2160 NULL, // referrer_tag is 0 for root 2161 len, 2162 (void*)user_data()); 2163 2164 if (res & JVMTI_VISIT_ABORT) { 2165 return false; 2166 } 2167 if (res & JVMTI_VISIT_OBJECTS) { 2168 check_for_visit(obj); 2169 } 2170 return true; 2171 } 2172 2173 // This mask is used to pass reference_info to a jvmtiHeapReferenceCallback 2174 // only for ref_kinds defined by the JVM TI spec. Otherwise, NULL is passed. 2175 #define REF_INFO_MASK ((1 << JVMTI_HEAP_REFERENCE_FIELD) \ 2176 | (1 << JVMTI_HEAP_REFERENCE_STATIC_FIELD) \ 2177 | (1 << JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT) \ 2178 | (1 << JVMTI_HEAP_REFERENCE_CONSTANT_POOL) \ 2179 | (1 << JVMTI_HEAP_REFERENCE_STACK_LOCAL) \ 2180 | (1 << JVMTI_HEAP_REFERENCE_JNI_LOCAL)) 2181 2182 // invoke the object reference callback to report a reference 2183 inline bool CallbackInvoker::invoke_advanced_object_reference_callback(jvmtiHeapReferenceKind ref_kind, 2184 oop referrer, 2185 oop obj, 2186 jint index) 2187 { 2188 // field index is only valid field in reference_info 2189 static jvmtiHeapReferenceInfo reference_info = { 0 }; 2190 2191 assert(ServiceUtil::visible_oop(referrer), "checking"); 2192 assert(ServiceUtil::visible_oop(obj), "checking"); 2193 2194 AdvancedHeapWalkContext* context = advanced_context(); 2195 2196 // check that callback is provider 2197 jvmtiHeapReferenceCallback cb = context->heap_reference_callback(); 2198 if (cb == NULL) { 2199 return check_for_visit(obj); 2200 } 2201 2202 // apply class filter 2203 if (is_filtered_by_klass_filter(obj, context->klass_filter())) { 2204 return check_for_visit(obj); 2205 } 2206 2207 // setup the callback wrapper 2208 TwoOopCallbackWrapper wrapper(tag_map(), referrer, obj); 2209 2210 // apply tag filter 2211 if (is_filtered_by_heap_filter(wrapper.obj_tag(), 2212 wrapper.klass_tag(), 2213 context->heap_filter())) { 2214 return check_for_visit(obj); 2215 } 2216 2217 // field index is only valid field in reference_info 2218 reference_info.field.index = index; 2219 2220 // for arrays we need the length, otherwise -1 2221 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1); 2222 2223 // invoke the callback 2224 int res = (*cb)(ref_kind, 2225 (REF_INFO_MASK & (1 << ref_kind)) ? &reference_info : NULL, 2226 wrapper.klass_tag(), 2227 wrapper.referrer_klass_tag(), 2228 wrapper.obj_size(), 2229 wrapper.obj_tag_p(), 2230 wrapper.referrer_tag_p(), 2231 len, 2232 (void*)user_data()); 2233 2234 if (res & JVMTI_VISIT_ABORT) { 2235 return false; 2236 } 2237 if (res & JVMTI_VISIT_OBJECTS) { 2238 check_for_visit(obj); 2239 } 2240 return true; 2241 } 2242 2243 // report a "simple root" 2244 inline bool CallbackInvoker::report_simple_root(jvmtiHeapReferenceKind kind, oop obj) { 2245 assert(kind != JVMTI_HEAP_REFERENCE_STACK_LOCAL && 2246 kind != JVMTI_HEAP_REFERENCE_JNI_LOCAL, "not a simple root"); 2247 assert(ServiceUtil::visible_oop(obj), "checking"); 2248 2249 if (is_basic_heap_walk()) { 2250 // map to old style root kind 2251 jvmtiHeapRootKind root_kind = toJvmtiHeapRootKind(kind); 2252 return invoke_basic_heap_root_callback(root_kind, obj); 2253 } else { 2254 assert(is_advanced_heap_walk(), "wrong heap walk type"); 2255 return invoke_advanced_heap_root_callback(kind, obj); 2256 } 2257 } 2258 2259 2260 // invoke the primitive array values 2261 inline bool CallbackInvoker::report_primitive_array_values(oop obj) { 2262 assert(obj->is_typeArray(), "not a primitive array"); 2263 2264 AdvancedHeapWalkContext* context = advanced_context(); 2265 assert(context->array_primitive_value_callback() != NULL, "no callback"); 2266 2267 // apply class filter 2268 if (is_filtered_by_klass_filter(obj, context->klass_filter())) { 2269 return true; 2270 } 2271 2272 CallbackWrapper wrapper(tag_map(), obj); 2273 2274 // apply tag filter 2275 if (is_filtered_by_heap_filter(wrapper.obj_tag(), 2276 wrapper.klass_tag(), 2277 context->heap_filter())) { 2278 return true; 2279 } 2280 2281 // invoke the callback 2282 int res = invoke_array_primitive_value_callback(context->array_primitive_value_callback(), 2283 &wrapper, 2284 obj, 2285 (void*)user_data()); 2286 return (!(res & JVMTI_VISIT_ABORT)); 2287 } 2288 2289 // invoke the string value callback 2290 inline bool CallbackInvoker::report_string_value(oop str) { 2291 assert(str->klass() == SystemDictionary::String_klass(), "not a string"); 2292 2293 AdvancedHeapWalkContext* context = advanced_context(); 2294 assert(context->string_primitive_value_callback() != NULL, "no callback"); 2295 2296 // apply class filter 2297 if (is_filtered_by_klass_filter(str, context->klass_filter())) { 2298 return true; 2299 } 2300 2301 CallbackWrapper wrapper(tag_map(), str); 2302 2303 // apply tag filter 2304 if (is_filtered_by_heap_filter(wrapper.obj_tag(), 2305 wrapper.klass_tag(), 2306 context->heap_filter())) { 2307 return true; 2308 } 2309 2310 // invoke the callback 2311 int res = invoke_string_value_callback(context->string_primitive_value_callback(), 2312 &wrapper, 2313 str, 2314 (void*)user_data()); 2315 return (!(res & JVMTI_VISIT_ABORT)); 2316 } 2317 2318 // invoke the primitive field callback 2319 inline bool CallbackInvoker::report_primitive_field(jvmtiHeapReferenceKind ref_kind, 2320 oop obj, 2321 jint index, 2322 address addr, 2323 char type) 2324 { 2325 // for primitive fields only the index will be set 2326 static jvmtiHeapReferenceInfo reference_info = { 0 }; 2327 2328 AdvancedHeapWalkContext* context = advanced_context(); 2329 assert(context->primitive_field_callback() != NULL, "no callback"); 2330 2331 // apply class filter 2332 if (is_filtered_by_klass_filter(obj, context->klass_filter())) { 2333 return true; 2334 } 2335 2336 CallbackWrapper wrapper(tag_map(), obj); 2337 2338 // apply tag filter 2339 if (is_filtered_by_heap_filter(wrapper.obj_tag(), 2340 wrapper.klass_tag(), 2341 context->heap_filter())) { 2342 return true; 2343 } 2344 2345 // the field index in the referrer 2346 reference_info.field.index = index; 2347 2348 // map the type 2349 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type; 2350 2351 // setup the jvalue 2352 jvalue value; 2353 copy_to_jvalue(&value, addr, value_type); 2354 2355 jvmtiPrimitiveFieldCallback cb = context->primitive_field_callback(); 2356 int res = (*cb)(ref_kind, 2357 &reference_info, 2358 wrapper.klass_tag(), 2359 wrapper.obj_tag_p(), 2360 value, 2361 value_type, 2362 (void*)user_data()); 2363 return (!(res & JVMTI_VISIT_ABORT)); 2364 } 2365 2366 2367 // instance field 2368 inline bool CallbackInvoker::report_primitive_instance_field(oop obj, 2369 jint index, 2370 address value, 2371 char type) { 2372 return report_primitive_field(JVMTI_HEAP_REFERENCE_FIELD, 2373 obj, 2374 index, 2375 value, 2376 type); 2377 } 2378 2379 // static field 2380 inline bool CallbackInvoker::report_primitive_static_field(oop obj, 2381 jint index, 2382 address value, 2383 char type) { 2384 return report_primitive_field(JVMTI_HEAP_REFERENCE_STATIC_FIELD, 2385 obj, 2386 index, 2387 value, 2388 type); 2389 } 2390 2391 // report a JNI local (root object) to the profiler 2392 inline bool CallbackInvoker::report_jni_local_root(jlong thread_tag, jlong tid, jint depth, jmethodID m, oop obj) { 2393 if (is_basic_heap_walk()) { 2394 return invoke_basic_stack_ref_callback(JVMTI_HEAP_ROOT_JNI_LOCAL, 2395 thread_tag, 2396 depth, 2397 m, 2398 -1, 2399 obj); 2400 } else { 2401 return invoke_advanced_stack_ref_callback(JVMTI_HEAP_REFERENCE_JNI_LOCAL, 2402 thread_tag, tid, 2403 depth, 2404 m, 2405 (jlocation)-1, 2406 -1, 2407 obj); 2408 } 2409 } 2410 2411 2412 // report a local (stack reference, root object) 2413 inline bool CallbackInvoker::report_stack_ref_root(jlong thread_tag, 2414 jlong tid, 2415 jint depth, 2416 jmethodID method, 2417 jlocation bci, 2418 jint slot, 2419 oop obj) { 2420 if (is_basic_heap_walk()) { 2421 return invoke_basic_stack_ref_callback(JVMTI_HEAP_ROOT_STACK_LOCAL, 2422 thread_tag, 2423 depth, 2424 method, 2425 slot, 2426 obj); 2427 } else { 2428 return invoke_advanced_stack_ref_callback(JVMTI_HEAP_REFERENCE_STACK_LOCAL, 2429 thread_tag, 2430 tid, 2431 depth, 2432 method, 2433 bci, 2434 slot, 2435 obj); 2436 } 2437 } 2438 2439 // report an object referencing a class. 2440 inline bool CallbackInvoker::report_class_reference(oop referrer, oop referree) { 2441 if (is_basic_heap_walk()) { 2442 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS, referrer, referree, -1); 2443 } else { 2444 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CLASS, referrer, referree, -1); 2445 } 2446 } 2447 2448 // report a class referencing its class loader. 2449 inline bool CallbackInvoker::report_class_loader_reference(oop referrer, oop referree) { 2450 if (is_basic_heap_walk()) { 2451 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS_LOADER, referrer, referree, -1); 2452 } else { 2453 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CLASS_LOADER, referrer, referree, -1); 2454 } 2455 } 2456 2457 // report a class referencing its signers. 2458 inline bool CallbackInvoker::report_signers_reference(oop referrer, oop referree) { 2459 if (is_basic_heap_walk()) { 2460 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_SIGNERS, referrer, referree, -1); 2461 } else { 2462 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_SIGNERS, referrer, referree, -1); 2463 } 2464 } 2465 2466 // report a class referencing its protection domain.. 2467 inline bool CallbackInvoker::report_protection_domain_reference(oop referrer, oop referree) { 2468 if (is_basic_heap_walk()) { 2469 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_PROTECTION_DOMAIN, referrer, referree, -1); 2470 } else { 2471 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_PROTECTION_DOMAIN, referrer, referree, -1); 2472 } 2473 } 2474 2475 // report a class referencing its superclass. 2476 inline bool CallbackInvoker::report_superclass_reference(oop referrer, oop referree) { 2477 if (is_basic_heap_walk()) { 2478 // Send this to be consistent with past implementation 2479 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS, referrer, referree, -1); 2480 } else { 2481 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_SUPERCLASS, referrer, referree, -1); 2482 } 2483 } 2484 2485 // report a class referencing one of its interfaces. 2486 inline bool CallbackInvoker::report_interface_reference(oop referrer, oop referree) { 2487 if (is_basic_heap_walk()) { 2488 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_INTERFACE, referrer, referree, -1); 2489 } else { 2490 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_INTERFACE, referrer, referree, -1); 2491 } 2492 } 2493 2494 // report a class referencing one of its static fields. 2495 inline bool CallbackInvoker::report_static_field_reference(oop referrer, oop referree, jint slot) { 2496 if (is_basic_heap_walk()) { 2497 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_STATIC_FIELD, referrer, referree, slot); 2498 } else { 2499 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_STATIC_FIELD, referrer, referree, slot); 2500 } 2501 } 2502 2503 // report an array referencing an element object 2504 inline bool CallbackInvoker::report_array_element_reference(oop referrer, oop referree, jint index) { 2505 if (is_basic_heap_walk()) { 2506 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_ARRAY_ELEMENT, referrer, referree, index); 2507 } else { 2508 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT, referrer, referree, index); 2509 } 2510 } 2511 2512 // report an object referencing an instance field object 2513 inline bool CallbackInvoker::report_field_reference(oop referrer, oop referree, jint slot) { 2514 if (is_basic_heap_walk()) { 2515 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_FIELD, referrer, referree, slot); 2516 } else { 2517 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_FIELD, referrer, referree, slot); 2518 } 2519 } 2520 2521 // report an array referencing an element object 2522 inline bool CallbackInvoker::report_constant_pool_reference(oop referrer, oop referree, jint index) { 2523 if (is_basic_heap_walk()) { 2524 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CONSTANT_POOL, referrer, referree, index); 2525 } else { 2526 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CONSTANT_POOL, referrer, referree, index); 2527 } 2528 } 2529 2530 // A supporting closure used to process simple roots 2531 class SimpleRootsClosure : public OopClosure { 2532 private: 2533 jvmtiHeapReferenceKind _kind; 2534 bool _continue; 2535 2536 jvmtiHeapReferenceKind root_kind() { return _kind; } 2537 2538 public: 2539 void set_kind(jvmtiHeapReferenceKind kind) { 2540 _kind = kind; 2541 _continue = true; 2542 } 2543 2544 inline bool stopped() { 2545 return !_continue; 2546 } 2547 2548 void do_oop(oop* obj_p) { 2549 // iteration has terminated 2550 if (stopped()) { 2551 return; 2552 } 2553 2554 // ignore null or deleted handles 2555 oop o = *obj_p; 2556 if (o == NULL || o == JNIHandles::deleted_handle()) { 2557 return; 2558 } 2559 2560 assert(Universe::heap()->is_in_reserved(o), "should be impossible"); 2561 2562 jvmtiHeapReferenceKind kind = root_kind(); 2563 if (kind == JVMTI_HEAP_REFERENCE_SYSTEM_CLASS) { 2564 // SystemDictionary::always_strong_oops_do reports the application 2565 // class loader as a root. We want this root to be reported as 2566 // a root kind of "OTHER" rather than "SYSTEM_CLASS". 2567 if (!o->is_instanceMirror()) { 2568 kind = JVMTI_HEAP_REFERENCE_OTHER; 2569 } 2570 } 2571 2572 // some objects are ignored - in the case of simple 2573 // roots it's mostly Symbol*s that we are skipping 2574 // here. 2575 if (!ServiceUtil::visible_oop(o)) { 2576 return; 2577 } 2578 2579 // invoke the callback 2580 _continue = CallbackInvoker::report_simple_root(kind, o); 2581 2582 } 2583 virtual void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); } 2584 }; 2585 2586 // A supporting closure used to process JNI locals 2587 class JNILocalRootsClosure : public OopClosure { 2588 private: 2589 jlong _thread_tag; 2590 jlong _tid; 2591 jint _depth; 2592 jmethodID _method; 2593 bool _continue; 2594 public: 2595 void set_context(jlong thread_tag, jlong tid, jint depth, jmethodID method) { 2596 _thread_tag = thread_tag; 2597 _tid = tid; 2598 _depth = depth; 2599 _method = method; 2600 _continue = true; 2601 } 2602 2603 inline bool stopped() { 2604 return !_continue; 2605 } 2606 2607 void do_oop(oop* obj_p) { 2608 // iteration has terminated 2609 if (stopped()) { 2610 return; 2611 } 2612 2613 // ignore null or deleted handles 2614 oop o = *obj_p; 2615 if (o == NULL || o == JNIHandles::deleted_handle()) { 2616 return; 2617 } 2618 2619 if (!ServiceUtil::visible_oop(o)) { 2620 return; 2621 } 2622 2623 // invoke the callback 2624 _continue = CallbackInvoker::report_jni_local_root(_thread_tag, _tid, _depth, _method, o); 2625 } 2626 virtual void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); } 2627 }; 2628 2629 2630 // A VM operation to iterate over objects that are reachable from 2631 // a set of roots or an initial object. 2632 // 2633 // For VM_HeapWalkOperation the set of roots used is :- 2634 // 2635 // - All JNI global references 2636 // - All inflated monitors 2637 // - All classes loaded by the boot class loader (or all classes 2638 // in the event that class unloading is disabled) 2639 // - All java threads 2640 // - For each java thread then all locals and JNI local references 2641 // on the thread's execution stack 2642 // - All visible/explainable objects from Universes::oops_do 2643 // 2644 class VM_HeapWalkOperation: public VM_Operation { 2645 private: 2646 enum { 2647 initial_visit_stack_size = 4000 2648 }; 2649 2650 bool _is_advanced_heap_walk; // indicates FollowReferences 2651 JvmtiTagMap* _tag_map; 2652 Handle _initial_object; 2653 GrowableArray<oop>* _visit_stack; // the visit stack 2654 2655 bool _collecting_heap_roots; // are we collecting roots 2656 bool _following_object_refs; // are we following object references 2657 2658 bool _reporting_primitive_fields; // optional reporting 2659 bool _reporting_primitive_array_values; 2660 bool _reporting_string_values; 2661 2662 GrowableArray<oop>* create_visit_stack() { 2663 return new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(initial_visit_stack_size, true); 2664 } 2665 2666 // accessors 2667 bool is_advanced_heap_walk() const { return _is_advanced_heap_walk; } 2668 JvmtiTagMap* tag_map() const { return _tag_map; } 2669 Handle initial_object() const { return _initial_object; } 2670 2671 bool is_following_references() const { return _following_object_refs; } 2672 2673 bool is_reporting_primitive_fields() const { return _reporting_primitive_fields; } 2674 bool is_reporting_primitive_array_values() const { return _reporting_primitive_array_values; } 2675 bool is_reporting_string_values() const { return _reporting_string_values; } 2676 2677 GrowableArray<oop>* visit_stack() const { return _visit_stack; } 2678 2679 // iterate over the various object types 2680 inline bool iterate_over_array(oop o); 2681 inline bool iterate_over_type_array(oop o); 2682 inline bool iterate_over_class(oop o); 2683 inline bool iterate_over_object(oop o); 2684 2685 // root collection 2686 inline bool collect_simple_roots(); 2687 inline bool collect_stack_roots(); 2688 inline bool collect_stack_roots(JavaThread* java_thread, JNILocalRootsClosure* blk); 2689 2690 // visit an object 2691 inline bool visit(oop o); 2692 2693 public: 2694 VM_HeapWalkOperation(JvmtiTagMap* tag_map, 2695 Handle initial_object, 2696 BasicHeapWalkContext callbacks, 2697 const void* user_data); 2698 2699 VM_HeapWalkOperation(JvmtiTagMap* tag_map, 2700 Handle initial_object, 2701 AdvancedHeapWalkContext callbacks, 2702 const void* user_data); 2703 2704 ~VM_HeapWalkOperation(); 2705 2706 VMOp_Type type() const { return VMOp_HeapWalkOperation; } 2707 void doit(); 2708 }; 2709 2710 2711 VM_HeapWalkOperation::VM_HeapWalkOperation(JvmtiTagMap* tag_map, 2712 Handle initial_object, 2713 BasicHeapWalkContext callbacks, 2714 const void* user_data) { 2715 _is_advanced_heap_walk = false; 2716 _tag_map = tag_map; 2717 _initial_object = initial_object; 2718 _following_object_refs = (callbacks.object_ref_callback() != NULL); 2719 _reporting_primitive_fields = false; 2720 _reporting_primitive_array_values = false; 2721 _reporting_string_values = false; 2722 _visit_stack = create_visit_stack(); 2723 2724 2725 CallbackInvoker::initialize_for_basic_heap_walk(tag_map, _visit_stack, user_data, callbacks); 2726 } 2727 2728 VM_HeapWalkOperation::VM_HeapWalkOperation(JvmtiTagMap* tag_map, 2729 Handle initial_object, 2730 AdvancedHeapWalkContext callbacks, 2731 const void* user_data) { 2732 _is_advanced_heap_walk = true; 2733 _tag_map = tag_map; 2734 _initial_object = initial_object; 2735 _following_object_refs = true; 2736 _reporting_primitive_fields = (callbacks.primitive_field_callback() != NULL);; 2737 _reporting_primitive_array_values = (callbacks.array_primitive_value_callback() != NULL);; 2738 _reporting_string_values = (callbacks.string_primitive_value_callback() != NULL);; 2739 _visit_stack = create_visit_stack(); 2740 2741 CallbackInvoker::initialize_for_advanced_heap_walk(tag_map, _visit_stack, user_data, callbacks); 2742 } 2743 2744 VM_HeapWalkOperation::~VM_HeapWalkOperation() { 2745 if (_following_object_refs) { 2746 assert(_visit_stack != NULL, "checking"); 2747 delete _visit_stack; 2748 _visit_stack = NULL; 2749 } 2750 } 2751 2752 // an array references its class and has a reference to 2753 // each element in the array 2754 inline bool VM_HeapWalkOperation::iterate_over_array(oop o) { 2755 objArrayOop array = objArrayOop(o); 2756 2757 // array reference to its class 2758 oop mirror = ObjArrayKlass::cast(array->klass())->java_mirror(); 2759 if (!CallbackInvoker::report_class_reference(o, mirror)) { 2760 return false; 2761 } 2762 2763 // iterate over the array and report each reference to a 2764 // non-null element 2765 for (int index=0; index<array->length(); index++) { 2766 oop elem = array->obj_at(index); 2767 if (elem == NULL) { 2768 continue; 2769 } 2770 2771 // report the array reference o[index] = elem 2772 if (!CallbackInvoker::report_array_element_reference(o, elem, index)) { 2773 return false; 2774 } 2775 } 2776 return true; 2777 } 2778 2779 // a type array references its class 2780 inline bool VM_HeapWalkOperation::iterate_over_type_array(oop o) { 2781 Klass* k = o->klass(); 2782 oop mirror = k->java_mirror(); 2783 if (!CallbackInvoker::report_class_reference(o, mirror)) { 2784 return false; 2785 } 2786 2787 // report the array contents if required 2788 if (is_reporting_primitive_array_values()) { 2789 if (!CallbackInvoker::report_primitive_array_values(o)) { 2790 return false; 2791 } 2792 } 2793 return true; 2794 } 2795 2796 #ifdef ASSERT 2797 // verify that a static oop field is in range 2798 static inline bool verify_static_oop(InstanceKlass* ik, 2799 oop mirror, int offset) { 2800 address obj_p = (address)mirror + offset; 2801 address start = (address)InstanceMirrorKlass::start_of_static_fields(mirror); 2802 address end = start + (java_lang_Class::static_oop_field_count(mirror) * heapOopSize); 2803 assert(end >= start, "sanity check"); 2804 2805 if (obj_p >= start && obj_p < end) { 2806 return true; 2807 } else { 2808 return false; 2809 } 2810 } 2811 #endif // #ifdef ASSERT 2812 2813 // a class references its super class, interfaces, class loader, ... 2814 // and finally its static fields 2815 inline bool VM_HeapWalkOperation::iterate_over_class(oop java_class) { 2816 int i; 2817 Klass* klass = java_lang_Class::as_Klass(java_class); 2818 2819 if (klass->oop_is_instance()) { 2820 InstanceKlass* ik = InstanceKlass::cast(klass); 2821 2822 // ignore the class if it's has been initialized yet 2823 if (!ik->is_linked()) { 2824 return true; 2825 } 2826 2827 // get the java mirror 2828 oop mirror = klass->java_mirror(); 2829 2830 // super (only if something more interesting than java.lang.Object) 2831 Klass* java_super = ik->java_super(); 2832 if (java_super != NULL && java_super != SystemDictionary::Object_klass()) { 2833 oop super = java_super->java_mirror(); 2834 if (!CallbackInvoker::report_superclass_reference(mirror, super)) { 2835 return false; 2836 } 2837 } 2838 2839 // class loader 2840 oop cl = ik->class_loader(); 2841 if (cl != NULL) { 2842 if (!CallbackInvoker::report_class_loader_reference(mirror, cl)) { 2843 return false; 2844 } 2845 } 2846 2847 // protection domain 2848 oop pd = ik->protection_domain(); 2849 if (pd != NULL) { 2850 if (!CallbackInvoker::report_protection_domain_reference(mirror, pd)) { 2851 return false; 2852 } 2853 } 2854 2855 // signers 2856 oop signers = ik->signers(); 2857 if (signers != NULL) { 2858 if (!CallbackInvoker::report_signers_reference(mirror, signers)) { 2859 return false; 2860 } 2861 } 2862 2863 // references from the constant pool 2864 { 2865 ConstantPool* pool = ik->constants(); 2866 for (int i = 1; i < pool->length(); i++) { 2867 constantTag tag = pool->tag_at(i).value(); 2868 if (tag.is_string() || tag.is_klass()) { 2869 oop entry; 2870 if (tag.is_string()) { 2871 entry = pool->resolved_string_at(i); 2872 // If the entry is non-null it is resolved. 2873 if (entry == NULL) continue; 2874 } else { 2875 entry = pool->resolved_klass_at(i)->java_mirror(); 2876 } 2877 if (!CallbackInvoker::report_constant_pool_reference(mirror, entry, (jint)i)) { 2878 return false; 2879 } 2880 } 2881 } 2882 } 2883 2884 // interfaces 2885 // (These will already have been reported as references from the constant pool 2886 // but are specified by IterateOverReachableObjects and must be reported). 2887 Array<Klass*>* interfaces = ik->local_interfaces(); 2888 for (i = 0; i < interfaces->length(); i++) { 2889 oop interf = ((Klass*)interfaces->at(i))->java_mirror(); 2890 if (interf == NULL) { 2891 continue; 2892 } 2893 if (!CallbackInvoker::report_interface_reference(mirror, interf)) { 2894 return false; 2895 } 2896 } 2897 2898 // iterate over the static fields 2899 2900 ClassFieldMap* field_map = ClassFieldMap::create_map_of_static_fields(klass); 2901 for (i=0; i<field_map->field_count(); i++) { 2902 ClassFieldDescriptor* field = field_map->field_at(i); 2903 char type = field->field_type(); 2904 if (!is_primitive_field_type(type)) { 2905 oop fld_o = mirror->obj_field(field->field_offset()); 2906 assert(verify_static_oop(ik, mirror, field->field_offset()), "sanity check"); 2907 if (fld_o != NULL) { 2908 int slot = field->field_index(); 2909 if (!CallbackInvoker::report_static_field_reference(mirror, fld_o, slot)) { 2910 delete field_map; 2911 return false; 2912 } 2913 } 2914 } else { 2915 if (is_reporting_primitive_fields()) { 2916 address addr = (address)mirror + field->field_offset(); 2917 int slot = field->field_index(); 2918 if (!CallbackInvoker::report_primitive_static_field(mirror, slot, addr, type)) { 2919 delete field_map; 2920 return false; 2921 } 2922 } 2923 } 2924 } 2925 delete field_map; 2926 2927 return true; 2928 } 2929 2930 return true; 2931 } 2932 2933 // an object references a class and its instance fields 2934 // (static fields are ignored here as we report these as 2935 // references from the class). 2936 inline bool VM_HeapWalkOperation::iterate_over_object(oop o) { 2937 // reference to the class 2938 if (!CallbackInvoker::report_class_reference(o, o->klass()->java_mirror())) { 2939 return false; 2940 } 2941 2942 // iterate over instance fields 2943 ClassFieldMap* field_map = JvmtiCachedClassFieldMap::get_map_of_instance_fields(o); 2944 for (int i=0; i<field_map->field_count(); i++) { 2945 ClassFieldDescriptor* field = field_map->field_at(i); 2946 char type = field->field_type(); 2947 if (!is_primitive_field_type(type)) { 2948 oop fld_o = o->obj_field(field->field_offset()); 2949 // ignore any objects that aren't visible to profiler 2950 if (fld_o != NULL && ServiceUtil::visible_oop(fld_o)) { 2951 assert(Universe::heap()->is_in_reserved(fld_o), "unsafe code should not " 2952 "have references to Klass* anymore"); 2953 int slot = field->field_index(); 2954 if (!CallbackInvoker::report_field_reference(o, fld_o, slot)) { 2955 return false; 2956 } 2957 } 2958 } else { 2959 if (is_reporting_primitive_fields()) { 2960 // primitive instance field 2961 address addr = (address)o + field->field_offset(); 2962 int slot = field->field_index(); 2963 if (!CallbackInvoker::report_primitive_instance_field(o, slot, addr, type)) { 2964 return false; 2965 } 2966 } 2967 } 2968 } 2969 2970 // if the object is a java.lang.String 2971 if (is_reporting_string_values() && 2972 o->klass() == SystemDictionary::String_klass()) { 2973 if (!CallbackInvoker::report_string_value(o)) { 2974 return false; 2975 } 2976 } 2977 return true; 2978 } 2979 2980 2981 // Collects all simple (non-stack) roots except for threads; 2982 // threads are handled in collect_stack_roots() as an optimization. 2983 // if there's a heap root callback provided then the callback is 2984 // invoked for each simple root. 2985 // if an object reference callback is provided then all simple 2986 // roots are pushed onto the marking stack so that they can be 2987 // processed later 2988 // 2989 inline bool VM_HeapWalkOperation::collect_simple_roots() { 2990 SimpleRootsClosure blk; 2991 2992 // JNI globals 2993 blk.set_kind(JVMTI_HEAP_REFERENCE_JNI_GLOBAL); 2994 JNIHandles::oops_do(&blk); 2995 if (blk.stopped()) { 2996 return false; 2997 } 2998 2999 // Preloaded classes and loader from the system dictionary 3000 blk.set_kind(JVMTI_HEAP_REFERENCE_SYSTEM_CLASS); 3001 SystemDictionary::always_strong_oops_do(&blk); 3002 KlassToOopClosure klass_blk(&blk); 3003 ClassLoaderDataGraph::always_strong_oops_do(&blk, &klass_blk, false); 3004 if (blk.stopped()) { 3005 return false; 3006 } 3007 3008 // Inflated monitors 3009 blk.set_kind(JVMTI_HEAP_REFERENCE_MONITOR); 3010 ObjectSynchronizer::oops_do(&blk); 3011 if (blk.stopped()) { 3012 return false; 3013 } 3014 3015 // threads are now handled in collect_stack_roots() 3016 3017 // Other kinds of roots maintained by HotSpot 3018 // Many of these won't be visible but others (such as instances of important 3019 // exceptions) will be visible. 3020 blk.set_kind(JVMTI_HEAP_REFERENCE_OTHER); 3021 Universe::oops_do(&blk); 3022 3023 // If there are any non-perm roots in the code cache, visit them. 3024 blk.set_kind(JVMTI_HEAP_REFERENCE_OTHER); 3025 CodeBlobToOopClosure look_in_blobs(&blk, !CodeBlobToOopClosure::FixRelocations); 3026 CodeCache::scavenge_root_nmethods_do(&look_in_blobs); 3027 3028 return true; 3029 } 3030 3031 // Walk the stack of a given thread and find all references (locals 3032 // and JNI calls) and report these as stack references 3033 inline bool VM_HeapWalkOperation::collect_stack_roots(JavaThread* java_thread, 3034 JNILocalRootsClosure* blk) 3035 { 3036 oop threadObj = java_thread->threadObj(); 3037 assert(threadObj != NULL, "sanity check"); 3038 3039 // only need to get the thread's tag once per thread 3040 jlong thread_tag = tag_for(_tag_map, threadObj); 3041 3042 // also need the thread id 3043 jlong tid = java_lang_Thread::thread_id(threadObj); 3044 3045 3046 if (java_thread->has_last_Java_frame()) { 3047 3048 // vframes are resource allocated 3049 Thread* current_thread = Thread::current(); 3050 ResourceMark rm(current_thread); 3051 HandleMark hm(current_thread); 3052 3053 RegisterMap reg_map(java_thread); 3054 frame f = java_thread->last_frame(); 3055 vframe* vf = vframe::new_vframe(&f, ®_map, java_thread); 3056 3057 bool is_top_frame = true; 3058 int depth = 0; 3059 frame* last_entry_frame = NULL; 3060 3061 while (vf != NULL) { 3062 if (vf->is_java_frame()) { 3063 3064 // java frame (interpreted, compiled, ...) 3065 javaVFrame *jvf = javaVFrame::cast(vf); 3066 3067 // the jmethodID 3068 jmethodID method = jvf->method()->jmethod_id(); 3069 3070 if (!(jvf->method()->is_native())) { 3071 jlocation bci = (jlocation)jvf->bci(); 3072 StackValueCollection* locals = jvf->locals(); 3073 for (int slot=0; slot<locals->size(); slot++) { 3074 if (locals->at(slot)->type() == T_OBJECT) { 3075 oop o = locals->obj_at(slot)(); 3076 if (o == NULL) { 3077 continue; 3078 } 3079 3080 // stack reference 3081 if (!CallbackInvoker::report_stack_ref_root(thread_tag, tid, depth, method, 3082 bci, slot, o)) { 3083 return false; 3084 } 3085 } 3086 } 3087 3088 StackValueCollection* exprs = jvf->expressions(); 3089 for (int index=0; index < exprs->size(); index++) { 3090 if (exprs->at(index)->type() == T_OBJECT) { 3091 oop o = exprs->obj_at(index)(); 3092 if (o == NULL) { 3093 continue; 3094 } 3095 3096 // stack reference 3097 if (!CallbackInvoker::report_stack_ref_root(thread_tag, tid, depth, method, 3098 bci, locals->size() + index, o)) { 3099 return false; 3100 } 3101 } 3102 } 3103 3104 } else { 3105 blk->set_context(thread_tag, tid, depth, method); 3106 if (is_top_frame) { 3107 // JNI locals for the top frame. 3108 java_thread->active_handles()->oops_do(blk); 3109 } else { 3110 if (last_entry_frame != NULL) { 3111 // JNI locals for the entry frame 3112 assert(last_entry_frame->is_entry_frame(), "checking"); 3113 last_entry_frame->entry_frame_call_wrapper()->handles()->oops_do(blk); 3114 } 3115 } 3116 } 3117 last_entry_frame = NULL; 3118 depth++; 3119 } else { 3120 // externalVFrame - for an entry frame then we report the JNI locals 3121 // when we find the corresponding javaVFrame 3122 frame* fr = vf->frame_pointer(); 3123 assert(fr != NULL, "sanity check"); 3124 if (fr->is_entry_frame()) { 3125 last_entry_frame = fr; 3126 } 3127 } 3128 3129 vf = vf->sender(); 3130 is_top_frame = false; 3131 } 3132 } else { 3133 // no last java frame but there may be JNI locals 3134 blk->set_context(thread_tag, tid, 0, (jmethodID)NULL); 3135 java_thread->active_handles()->oops_do(blk); 3136 } 3137 return true; 3138 } 3139 3140 3141 // Collects the simple roots for all threads and collects all 3142 // stack roots - for each thread it walks the execution 3143 // stack to find all references and local JNI refs. 3144 inline bool VM_HeapWalkOperation::collect_stack_roots() { 3145 JNILocalRootsClosure blk; 3146 for (JavaThread* thread = Threads::first(); thread != NULL ; thread = thread->next()) { 3147 oop threadObj = thread->threadObj(); 3148 if (threadObj != NULL && !thread->is_exiting() && !thread->is_hidden_from_external_view()) { 3149 // Collect the simple root for this thread before we 3150 // collect its stack roots 3151 if (!CallbackInvoker::report_simple_root(JVMTI_HEAP_REFERENCE_THREAD, 3152 threadObj)) { 3153 return false; 3154 } 3155 if (!collect_stack_roots(thread, &blk)) { 3156 return false; 3157 } 3158 } 3159 } 3160 return true; 3161 } 3162 3163 // visit an object 3164 // first mark the object as visited 3165 // second get all the outbound references from this object (in other words, all 3166 // the objects referenced by this object). 3167 // 3168 bool VM_HeapWalkOperation::visit(oop o) { 3169 // mark object as visited 3170 assert(!ObjectMarker::visited(o), "can't visit same object more than once"); 3171 ObjectMarker::mark(o); 3172 3173 // instance 3174 if (o->is_instance()) { 3175 if (o->klass() == SystemDictionary::Class_klass()) { 3176 if (!java_lang_Class::is_primitive(o)) { 3177 // a java.lang.Class 3178 return iterate_over_class(o); 3179 } 3180 } else { 3181 return iterate_over_object(o); 3182 } 3183 } 3184 3185 // object array 3186 if (o->is_objArray()) { 3187 return iterate_over_array(o); 3188 } 3189 3190 // type array 3191 if (o->is_typeArray()) { 3192 return iterate_over_type_array(o); 3193 } 3194 3195 return true; 3196 } 3197 3198 void VM_HeapWalkOperation::doit() { 3199 ResourceMark rm; 3200 ObjectMarkerController marker; 3201 ClassFieldMapCacheMark cm; 3202 3203 assert(visit_stack()->is_empty(), "visit stack must be empty"); 3204 3205 // the heap walk starts with an initial object or the heap roots 3206 if (initial_object().is_null()) { 3207 // If either collect_stack_roots() or collect_simple_roots() 3208 // returns false at this point, then there are no mark bits 3209 // to reset. 3210 ObjectMarker::set_needs_reset(false); 3211 3212 // Calling collect_stack_roots() before collect_simple_roots() 3213 // can result in a big performance boost for an agent that is 3214 // focused on analyzing references in the thread stacks. 3215 if (!collect_stack_roots()) return; 3216 3217 if (!collect_simple_roots()) return; 3218 3219 // no early return so enable heap traversal to reset the mark bits 3220 ObjectMarker::set_needs_reset(true); 3221 } else { 3222 visit_stack()->push(initial_object()()); 3223 } 3224 3225 // object references required 3226 if (is_following_references()) { 3227 3228 // visit each object until all reachable objects have been 3229 // visited or the callback asked to terminate the iteration. 3230 while (!visit_stack()->is_empty()) { 3231 oop o = visit_stack()->pop(); 3232 if (!ObjectMarker::visited(o)) { 3233 if (!visit(o)) { 3234 break; 3235 } 3236 } 3237 } 3238 } 3239 } 3240 3241 // iterate over all objects that are reachable from a set of roots 3242 void JvmtiTagMap::iterate_over_reachable_objects(jvmtiHeapRootCallback heap_root_callback, 3243 jvmtiStackReferenceCallback stack_ref_callback, 3244 jvmtiObjectReferenceCallback object_ref_callback, 3245 const void* user_data) { 3246 MutexLocker ml(Heap_lock); 3247 BasicHeapWalkContext context(heap_root_callback, stack_ref_callback, object_ref_callback); 3248 VM_HeapWalkOperation op(this, Handle(), context, user_data); 3249 VMThread::execute(&op); 3250 } 3251 3252 // iterate over all objects that are reachable from a given object 3253 void JvmtiTagMap::iterate_over_objects_reachable_from_object(jobject object, 3254 jvmtiObjectReferenceCallback object_ref_callback, 3255 const void* user_data) { 3256 oop obj = JNIHandles::resolve(object); 3257 Handle initial_object(Thread::current(), obj); 3258 3259 MutexLocker ml(Heap_lock); 3260 BasicHeapWalkContext context(NULL, NULL, object_ref_callback); 3261 VM_HeapWalkOperation op(this, initial_object, context, user_data); 3262 VMThread::execute(&op); 3263 } 3264 3265 // follow references from an initial object or the GC roots 3266 void JvmtiTagMap::follow_references(jint heap_filter, 3267 KlassHandle klass, 3268 jobject object, 3269 const jvmtiHeapCallbacks* callbacks, 3270 const void* user_data) 3271 { 3272 oop obj = JNIHandles::resolve(object); 3273 Handle initial_object(Thread::current(), obj); 3274 3275 MutexLocker ml(Heap_lock); 3276 AdvancedHeapWalkContext context(heap_filter, klass, callbacks); 3277 VM_HeapWalkOperation op(this, initial_object, context, user_data); 3278 VMThread::execute(&op); 3279 } 3280 3281 3282 void JvmtiTagMap::weak_oops_do(BoolObjectClosure* is_alive, OopClosure* f) { 3283 // No locks during VM bring-up (0 threads) and no safepoints after main 3284 // thread creation and before VMThread creation (1 thread); initial GC 3285 // verification can happen in that window which gets to here. 3286 assert(Threads::number_of_threads() <= 1 || 3287 SafepointSynchronize::is_at_safepoint(), 3288 "must be executed at a safepoint"); 3289 if (JvmtiEnv::environments_might_exist()) { 3290 JvmtiEnvIterator it; 3291 for (JvmtiEnvBase* env = it.first(); env != NULL; env = it.next(env)) { 3292 JvmtiTagMap* tag_map = env->tag_map(); 3293 if (tag_map != NULL && !tag_map->is_empty()) { 3294 tag_map->do_weak_oops(is_alive, f); 3295 } 3296 } 3297 } 3298 } 3299 3300 void JvmtiTagMap::do_weak_oops(BoolObjectClosure* is_alive, OopClosure* f) { 3301 3302 // does this environment have the OBJECT_FREE event enabled 3303 bool post_object_free = env()->is_enabled(JVMTI_EVENT_OBJECT_FREE); 3304 3305 // counters used for trace message 3306 int freed = 0; 3307 int moved = 0; 3308 3309 JvmtiTagHashmap* hashmap = this->hashmap(); 3310 3311 // reenable sizing (if disabled) 3312 hashmap->set_resizing_enabled(true); 3313 3314 // if the hashmap is empty then we can skip it 3315 if (hashmap->_entry_count == 0) { 3316 return; 3317 } 3318 3319 // now iterate through each entry in the table 3320 3321 JvmtiTagHashmapEntry** table = hashmap->table(); 3322 int size = hashmap->size(); 3323 3324 JvmtiTagHashmapEntry* delayed_add = NULL; 3325 3326 for (int pos = 0; pos < size; ++pos) { 3327 JvmtiTagHashmapEntry* entry = table[pos]; 3328 JvmtiTagHashmapEntry* prev = NULL; 3329 3330 while (entry != NULL) { 3331 JvmtiTagHashmapEntry* next = entry->next(); 3332 3333 oop* obj = entry->object_addr(); 3334 3335 // has object been GC'ed 3336 if (!is_alive->do_object_b(entry->object())) { 3337 // grab the tag 3338 jlong tag = entry->tag(); 3339 guarantee(tag != 0, "checking"); 3340 3341 // remove GC'ed entry from hashmap and return the 3342 // entry to the free list 3343 hashmap->remove(prev, pos, entry); 3344 destroy_entry(entry); 3345 3346 // post the event to the profiler 3347 if (post_object_free) { 3348 JvmtiExport::post_object_free(env(), tag); 3349 } 3350 3351 ++freed; 3352 } else { 3353 f->do_oop(entry->object_addr()); 3354 oop new_oop = entry->object(); 3355 3356 // if the object has moved then re-hash it and move its 3357 // entry to its new location. 3358 unsigned int new_pos = JvmtiTagHashmap::hash(new_oop, size); 3359 if (new_pos != (unsigned int)pos) { 3360 if (prev == NULL) { 3361 table[pos] = next; 3362 } else { 3363 prev->set_next(next); 3364 } 3365 if (new_pos < (unsigned int)pos) { 3366 entry->set_next(table[new_pos]); 3367 table[new_pos] = entry; 3368 } else { 3369 // Delay adding this entry to it's new position as we'd end up 3370 // hitting it again during this iteration. 3371 entry->set_next(delayed_add); 3372 delayed_add = entry; 3373 } 3374 moved++; 3375 } else { 3376 // object didn't move 3377 prev = entry; 3378 } 3379 } 3380 3381 entry = next; 3382 } 3383 } 3384 3385 // Re-add all the entries which were kept aside 3386 while (delayed_add != NULL) { 3387 JvmtiTagHashmapEntry* next = delayed_add->next(); 3388 unsigned int pos = JvmtiTagHashmap::hash(delayed_add->object(), size); 3389 delayed_add->set_next(table[pos]); 3390 table[pos] = delayed_add; 3391 delayed_add = next; 3392 } 3393 3394 // stats 3395 if (TraceJVMTIObjectTagging) { 3396 int post_total = hashmap->_entry_count; 3397 int pre_total = post_total + freed; 3398 3399 tty->print_cr("(%d->%d, %d freed, %d total moves)", 3400 pre_total, post_total, freed, moved); 3401 } 3402 }