1 /* 2 * Copyright (c) 2018, 2020, 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/javaClasses.inline.hpp" 27 #include "classfile/stringTable.hpp" 28 #include "classfile/symbolTable.hpp" 29 #include "classfile/systemDictionaryShared.hpp" 30 #include "classfile/vmSymbols.hpp" 31 #include "logging/log.hpp" 32 #include "logging/logMessage.hpp" 33 #include "logging/logStream.hpp" 34 #include "memory/archiveUtils.hpp" 35 #include "memory/filemap.hpp" 36 #include "memory/heapShared.inline.hpp" 37 #include "memory/iterator.inline.hpp" 38 #include "memory/metadataFactory.hpp" 39 #include "memory/metaspaceClosure.hpp" 40 #include "memory/metaspaceShared.hpp" 41 #include "memory/resourceArea.hpp" 42 #include "memory/universe.hpp" 43 #include "oops/compressedOops.inline.hpp" 44 #include "oops/fieldStreams.inline.hpp" 45 #include "oops/oop.inline.hpp" 46 #include "runtime/fieldDescriptor.inline.hpp" 47 #include "runtime/safepointVerifiers.hpp" 48 #include "utilities/bitMap.inline.hpp" 49 #if INCLUDE_G1GC 50 #include "gc/g1/g1CollectedHeap.hpp" 51 #endif 52 53 #if INCLUDE_CDS_JAVA_HEAP 54 55 bool HeapShared::_closed_archive_heap_region_mapped = false; 56 bool HeapShared::_open_archive_heap_region_mapped = false; 57 bool HeapShared::_archive_heap_region_fixed = false; 58 59 address HeapShared::_narrow_oop_base; 60 int HeapShared::_narrow_oop_shift; 61 62 // 63 // If you add new entries to the following tables, you should know what you're doing! 64 // 65 66 // Entry fields for shareable subgraphs archived in the closed archive heap 67 // region. Warning: Objects in the subgraphs should not have reference fields 68 // assigned at runtime. 69 static ArchivableStaticFieldInfo closed_archive_subgraph_entry_fields[] = { 70 {"java/lang/Integer$IntegerCache", "archivedCache"}, 71 {"java/lang/Long$LongCache", "archivedCache"}, 72 {"java/lang/Byte$ByteCache", "archivedCache"}, 73 {"java/lang/Short$ShortCache", "archivedCache"}, 74 {"java/lang/Character$CharacterCache", "archivedCache"}, 75 {"java/util/jar/Attributes$Name", "KNOWN_NAMES"}, 76 {"sun/util/locale/BaseLocale", "constantBaseLocales"}, 77 }; 78 // Entry fields for subgraphs archived in the open archive heap region. 79 static ArchivableStaticFieldInfo open_archive_subgraph_entry_fields[] = { 80 {"jdk/internal/module/ArchivedModuleGraph", "archivedModuleGraph"}, 81 {"java/util/ImmutableCollections", "archivedObjects"}, 82 {"java/lang/module/Configuration", "EMPTY_CONFIGURATION"}, 83 {"jdk/internal/math/FDBigInteger", "archivedCaches"}, 84 }; 85 86 const static int num_closed_archive_subgraph_entry_fields = 87 sizeof(closed_archive_subgraph_entry_fields) / sizeof(ArchivableStaticFieldInfo); 88 const static int num_open_archive_subgraph_entry_fields = 89 sizeof(open_archive_subgraph_entry_fields) / sizeof(ArchivableStaticFieldInfo); 90 91 //////////////////////////////////////////////////////////////// 92 // 93 // Java heap object archiving support 94 // 95 //////////////////////////////////////////////////////////////// 96 void HeapShared::fixup_mapped_heap_regions() { 97 FileMapInfo *mapinfo = FileMapInfo::current_info(); 98 mapinfo->fixup_mapped_heap_regions(); 99 set_archive_heap_region_fixed(); 100 } 101 102 unsigned HeapShared::oop_hash(oop const& p) { 103 assert(!p->mark().has_bias_pattern(), 104 "this object should never have been locked"); // so identity_hash won't safepoin 105 unsigned hash = (unsigned)p->identity_hash(); 106 return hash; 107 } 108 109 HeapShared::ArchivedObjectCache* HeapShared::_archived_object_cache = NULL; 110 oop HeapShared::find_archived_heap_object(oop obj) { 111 assert(DumpSharedSpaces, "dump-time only"); 112 ArchivedObjectCache* cache = archived_object_cache(); 113 oop* p = cache->get(obj); 114 if (p != NULL) { 115 return *p; 116 } else { 117 return NULL; 118 } 119 } 120 121 oop HeapShared::archive_heap_object(oop obj, Thread* THREAD) { 122 assert(DumpSharedSpaces, "dump-time only"); 123 124 oop ao = find_archived_heap_object(obj); 125 if (ao != NULL) { 126 // already archived 127 return ao; 128 } 129 130 int len = obj->size(); 131 if (G1CollectedHeap::heap()->is_archive_alloc_too_large(len)) { 132 log_debug(cds, heap)("Cannot archive, object (" PTR_FORMAT ") is too large: " SIZE_FORMAT, 133 p2i(obj), (size_t)obj->size()); 134 return NULL; 135 } 136 137 // Pre-compute object identity hash at CDS dump time. 138 obj->identity_hash(); 139 140 oop archived_oop = (oop)G1CollectedHeap::heap()->archive_mem_allocate(len); 141 if (archived_oop != NULL) { 142 Copy::aligned_disjoint_words(cast_from_oop<HeapWord*>(obj), cast_from_oop<HeapWord*>(archived_oop), len); 143 MetaspaceShared::relocate_klass_ptr(archived_oop); 144 ArchivedObjectCache* cache = archived_object_cache(); 145 cache->put(obj, archived_oop); 146 log_debug(cds, heap)("Archived heap object " PTR_FORMAT " ==> " PTR_FORMAT, 147 p2i(obj), p2i(archived_oop)); 148 } else { 149 log_error(cds, heap)( 150 "Cannot allocate space for object " PTR_FORMAT " in archived heap region", 151 p2i(obj)); 152 vm_exit(1); 153 } 154 return archived_oop; 155 } 156 157 oop HeapShared::materialize_archived_object(narrowOop v) { 158 assert(archive_heap_region_fixed(), 159 "must be called after archive heap regions are fixed"); 160 if (!CompressedOops::is_null(v)) { 161 oop obj = HeapShared::decode_from_archive(v); 162 return G1CollectedHeap::heap()->materialize_archived_object(obj); 163 } 164 return NULL; 165 } 166 167 void HeapShared::archive_klass_objects(Thread* THREAD) { 168 GrowableArray<Klass*>* klasses = MetaspaceShared::collected_klasses(); 169 assert(klasses != NULL, "sanity"); 170 for (int i = 0; i < klasses->length(); i++) { 171 Klass* k = klasses->at(i); 172 173 // archive mirror object 174 java_lang_Class::archive_mirror(k, CHECK); 175 176 // archive the resolved_referenes array 177 if (k->is_instance_klass()) { 178 InstanceKlass* ik = InstanceKlass::cast(k); 179 ik->constants()->archive_resolved_references(THREAD); 180 } 181 } 182 } 183 184 void HeapShared::archive_java_heap_objects(GrowableArray<MemRegion> *closed, 185 GrowableArray<MemRegion> *open) { 186 if (!is_heap_object_archiving_allowed()) { 187 log_info(cds)( 188 "Archived java heap is not supported as UseG1GC, " 189 "UseCompressedOops and UseCompressedClassPointers are required." 190 "Current settings: UseG1GC=%s, UseCompressedOops=%s, UseCompressedClassPointers=%s.", 191 BOOL_TO_STR(UseG1GC), BOOL_TO_STR(UseCompressedOops), 192 BOOL_TO_STR(UseCompressedClassPointers)); 193 return; 194 } 195 196 G1HeapVerifier::verify_ready_for_archiving(); 197 198 { 199 NoSafepointVerifier nsv; 200 201 // Cache for recording where the archived objects are copied to 202 create_archived_object_cache(); 203 204 log_info(cds)("Dumping objects to closed archive heap region ..."); 205 NOT_PRODUCT(StringTable::verify()); 206 copy_closed_archive_heap_objects(closed); 207 208 log_info(cds)("Dumping objects to open archive heap region ..."); 209 copy_open_archive_heap_objects(open); 210 211 destroy_archived_object_cache(); 212 } 213 214 G1HeapVerifier::verify_archive_regions(); 215 } 216 217 void HeapShared::copy_closed_archive_heap_objects( 218 GrowableArray<MemRegion> * closed_archive) { 219 assert(is_heap_object_archiving_allowed(), "Cannot archive java heap objects"); 220 221 Thread* THREAD = Thread::current(); 222 G1CollectedHeap::heap()->begin_archive_alloc_range(); 223 224 // Archive interned string objects 225 StringTable::write_to_archive(); 226 227 archive_object_subgraphs(closed_archive_subgraph_entry_fields, 228 num_closed_archive_subgraph_entry_fields, 229 true /* is_closed_archive */, THREAD); 230 231 G1CollectedHeap::heap()->end_archive_alloc_range(closed_archive, 232 os::vm_allocation_granularity()); 233 } 234 235 void HeapShared::copy_open_archive_heap_objects( 236 GrowableArray<MemRegion> * open_archive) { 237 assert(is_heap_object_archiving_allowed(), "Cannot archive java heap objects"); 238 239 Thread* THREAD = Thread::current(); 240 G1CollectedHeap::heap()->begin_archive_alloc_range(true /* open */); 241 242 java_lang_Class::archive_basic_type_mirrors(THREAD); 243 244 archive_klass_objects(THREAD); 245 246 archive_object_subgraphs(open_archive_subgraph_entry_fields, 247 num_open_archive_subgraph_entry_fields, 248 false /* is_closed_archive */, 249 THREAD); 250 251 G1CollectedHeap::heap()->end_archive_alloc_range(open_archive, 252 os::vm_allocation_granularity()); 253 } 254 255 void HeapShared::init_narrow_oop_decoding(address base, int shift) { 256 _narrow_oop_base = base; 257 _narrow_oop_shift = shift; 258 } 259 260 // 261 // Subgraph archiving support 262 // 263 HeapShared::DumpTimeKlassSubGraphInfoTable* HeapShared::_dump_time_subgraph_info_table = NULL; 264 HeapShared::RunTimeKlassSubGraphInfoTable HeapShared::_run_time_subgraph_info_table; 265 266 // Get the subgraph_info for Klass k. A new subgraph_info is created if 267 // there is no existing one for k. The subgraph_info records the relocated 268 // Klass* of the original k. 269 KlassSubGraphInfo* HeapShared::get_subgraph_info(Klass* k) { 270 assert(DumpSharedSpaces, "dump time only"); 271 Klass* relocated_k = MetaspaceShared::get_relocated_klass(k); 272 KlassSubGraphInfo* info = _dump_time_subgraph_info_table->get(relocated_k); 273 if (info == NULL) { 274 _dump_time_subgraph_info_table->put(relocated_k, KlassSubGraphInfo(relocated_k)); 275 info = _dump_time_subgraph_info_table->get(relocated_k); 276 ++ _dump_time_subgraph_info_table->_count; 277 } 278 return info; 279 } 280 281 // Add an entry field to the current KlassSubGraphInfo. 282 void KlassSubGraphInfo::add_subgraph_entry_field( 283 int static_field_offset, oop v, bool is_closed_archive) { 284 assert(DumpSharedSpaces, "dump time only"); 285 if (_subgraph_entry_fields == NULL) { 286 _subgraph_entry_fields = 287 new(ResourceObj::C_HEAP, mtClass) GrowableArray<juint>(10, true); 288 } 289 _subgraph_entry_fields->append((juint)static_field_offset); 290 _subgraph_entry_fields->append(CompressedOops::encode(v)); 291 _subgraph_entry_fields->append(is_closed_archive ? 1 : 0); 292 } 293 294 // Add the Klass* for an object in the current KlassSubGraphInfo's subgraphs. 295 // Only objects of boot classes can be included in sub-graph. 296 void KlassSubGraphInfo::add_subgraph_object_klass(Klass* orig_k, Klass *relocated_k) { 297 assert(DumpSharedSpaces, "dump time only"); 298 assert(relocated_k == MetaspaceShared::get_relocated_klass(orig_k), 299 "must be the relocated Klass in the shared space"); 300 301 if (_subgraph_object_klasses == NULL) { 302 _subgraph_object_klasses = 303 new(ResourceObj::C_HEAP, mtClass) GrowableArray<Klass*>(50, true); 304 } 305 306 assert(relocated_k->is_shared(), "must be a shared class"); 307 308 if (_k == relocated_k) { 309 // Don't add the Klass containing the sub-graph to it's own klass 310 // initialization list. 311 return; 312 } 313 314 if (relocated_k->is_instance_klass()) { 315 assert(InstanceKlass::cast(relocated_k)->is_shared_boot_class(), 316 "must be boot class"); 317 // SystemDictionary::xxx_klass() are not updated, need to check 318 // the original Klass* 319 if (orig_k == SystemDictionary::String_klass() || 320 orig_k == SystemDictionary::Object_klass()) { 321 // Initialized early during VM initialization. No need to be added 322 // to the sub-graph object class list. 323 return; 324 } 325 } else if (relocated_k->is_objArray_klass()) { 326 Klass* abk = ObjArrayKlass::cast(relocated_k)->bottom_klass(); 327 if (abk->is_instance_klass()) { 328 assert(InstanceKlass::cast(abk)->is_shared_boot_class(), 329 "must be boot class"); 330 } 331 if (relocated_k == Universe::objectArrayKlassObj()) { 332 // Initialized early during Universe::genesis. No need to be added 333 // to the list. 334 return; 335 } 336 } else { 337 assert(relocated_k->is_typeArray_klass(), "must be"); 338 // Primitive type arrays are created early during Universe::genesis. 339 return; 340 } 341 342 if (log_is_enabled(Debug, cds, heap)) { 343 if (!_subgraph_object_klasses->contains(relocated_k)) { 344 ResourceMark rm; 345 log_debug(cds, heap)("Adding klass %s", orig_k->external_name()); 346 } 347 } 348 349 _subgraph_object_klasses->append_if_missing(relocated_k); 350 } 351 352 // Initialize an archived subgraph_info_record from the given KlassSubGraphInfo. 353 void ArchivedKlassSubGraphInfoRecord::init(KlassSubGraphInfo* info) { 354 _k = info->klass(); 355 _entry_field_records = NULL; 356 _subgraph_object_klasses = NULL; 357 358 // populate the entry fields 359 GrowableArray<juint>* entry_fields = info->subgraph_entry_fields(); 360 if (entry_fields != NULL) { 361 int num_entry_fields = entry_fields->length(); 362 assert(num_entry_fields % 3 == 0, "sanity"); 363 _entry_field_records = 364 MetaspaceShared::new_ro_array<juint>(num_entry_fields); 365 for (int i = 0 ; i < num_entry_fields; i++) { 366 _entry_field_records->at_put(i, entry_fields->at(i)); 367 } 368 } 369 370 // the Klasses of the objects in the sub-graphs 371 GrowableArray<Klass*>* subgraph_object_klasses = info->subgraph_object_klasses(); 372 if (subgraph_object_klasses != NULL) { 373 int num_subgraphs_klasses = subgraph_object_klasses->length(); 374 _subgraph_object_klasses = 375 MetaspaceShared::new_ro_array<Klass*>(num_subgraphs_klasses); 376 for (int i = 0; i < num_subgraphs_klasses; i++) { 377 Klass* subgraph_k = subgraph_object_klasses->at(i); 378 if (log_is_enabled(Info, cds, heap)) { 379 ResourceMark rm; 380 log_info(cds, heap)( 381 "Archived object klass %s (%2d) => %s", 382 _k->external_name(), i, subgraph_k->external_name()); 383 } 384 _subgraph_object_klasses->at_put(i, subgraph_k); 385 ArchivePtrMarker::mark_pointer(_subgraph_object_klasses->adr_at(i)); 386 } 387 } 388 389 ArchivePtrMarker::mark_pointer(&_k); 390 ArchivePtrMarker::mark_pointer(&_entry_field_records); 391 ArchivePtrMarker::mark_pointer(&_subgraph_object_klasses); 392 } 393 394 struct CopyKlassSubGraphInfoToArchive : StackObj { 395 CompactHashtableWriter* _writer; 396 CopyKlassSubGraphInfoToArchive(CompactHashtableWriter* writer) : _writer(writer) {} 397 398 bool do_entry(Klass* klass, KlassSubGraphInfo& info) { 399 if (info.subgraph_object_klasses() != NULL || info.subgraph_entry_fields() != NULL) { 400 ArchivedKlassSubGraphInfoRecord* record = 401 (ArchivedKlassSubGraphInfoRecord*)MetaspaceShared::read_only_space_alloc(sizeof(ArchivedKlassSubGraphInfoRecord)); 402 record->init(&info); 403 404 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary(klass); 405 u4 delta = MetaspaceShared::object_delta_u4(record); 406 _writer->add(hash, delta); 407 } 408 return true; // keep on iterating 409 } 410 }; 411 412 // Build the records of archived subgraph infos, which include: 413 // - Entry points to all subgraphs from the containing class mirror. The entry 414 // points are static fields in the mirror. For each entry point, the field 415 // offset, value and is_closed_archive flag are recorded in the sub-graph 416 // info. The value is stored back to the corresponding field at runtime. 417 // - A list of klasses that need to be loaded/initialized before archived 418 // java object sub-graph can be accessed at runtime. 419 void HeapShared::write_subgraph_info_table() { 420 // Allocate the contents of the hashtable(s) inside the RO region of the CDS archive. 421 DumpTimeKlassSubGraphInfoTable* d_table = _dump_time_subgraph_info_table; 422 CompactHashtableStats stats; 423 424 _run_time_subgraph_info_table.reset(); 425 426 CompactHashtableWriter writer(d_table->_count, &stats); 427 CopyKlassSubGraphInfoToArchive copy(&writer); 428 d_table->iterate(©); 429 430 writer.dump(&_run_time_subgraph_info_table, "subgraphs"); 431 } 432 433 void HeapShared::serialize_subgraph_info_table_header(SerializeClosure* soc) { 434 _run_time_subgraph_info_table.serialize_header(soc); 435 } 436 437 void HeapShared::initialize_from_archived_subgraph(Klass* k) { 438 if (!open_archive_heap_region_mapped()) { 439 return; // nothing to do 440 } 441 assert(!DumpSharedSpaces, "Should not be called with DumpSharedSpaces"); 442 443 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary(k); 444 const ArchivedKlassSubGraphInfoRecord* record = _run_time_subgraph_info_table.lookup(k, hash, 0); 445 446 // Initialize from archived data. Currently this is done only 447 // during VM initialization time. No lock is needed. 448 if (record != NULL) { 449 Thread* THREAD = Thread::current(); 450 451 int i; 452 // Load/link/initialize the klasses of the objects in the subgraph. 453 // NULL class loader is used. 454 Array<Klass*>* klasses = record->subgraph_object_klasses(); 455 if (klasses != NULL) { 456 for (i = 0; i < klasses->length(); i++) { 457 Klass* obj_k = klasses->at(i); 458 Klass* resolved_k = SystemDictionary::resolve_or_null( 459 (obj_k)->name(), THREAD); 460 if (resolved_k != obj_k) { 461 assert(!SystemDictionary::is_well_known_klass(resolved_k), 462 "shared well-known classes must not be replaced by JVMTI ClassFileLoadHook"); 463 ResourceMark rm(THREAD); 464 log_info(cds, heap)("Failed to load subgraph because %s was not loaded from archive", 465 resolved_k->external_name()); 466 return; 467 } 468 if ((obj_k)->is_instance_klass()) { 469 InstanceKlass* ik = InstanceKlass::cast(obj_k); 470 ik->initialize(THREAD); 471 } else if ((obj_k)->is_objArray_klass()) { 472 ObjArrayKlass* oak = ObjArrayKlass::cast(obj_k); 473 oak->initialize(THREAD); 474 } 475 } 476 } 477 478 if (HAS_PENDING_EXCEPTION) { 479 CLEAR_PENDING_EXCEPTION; 480 // None of the field value will be set if there was an exception. 481 // The java code will not see any of the archived objects in the 482 // subgraphs referenced from k in this case. 483 return; 484 } 485 486 // Load the subgraph entry fields from the record and store them back to 487 // the corresponding fields within the mirror. 488 oop m = k->java_mirror(); 489 Array<juint>* entry_field_records = record->entry_field_records(); 490 if (entry_field_records != NULL) { 491 int efr_len = entry_field_records->length(); 492 assert(efr_len % 3 == 0, "sanity"); 493 for (i = 0; i < efr_len;) { 494 int field_offset = entry_field_records->at(i); 495 narrowOop nv = entry_field_records->at(i+1); 496 int is_closed_archive = entry_field_records->at(i+2); 497 oop v; 498 if (is_closed_archive == 0) { 499 // It's an archived object in the open archive heap regions, not shared. 500 // The object refereced by the field becomes 'known' by GC from this 501 // point. All objects in the subgraph reachable from the object are 502 // also 'known' by GC. 503 v = materialize_archived_object(nv); 504 } else { 505 // Shared object in the closed archive heap regions. Decode directly. 506 assert(!CompressedOops::is_null(nv), "shared object is null"); 507 v = HeapShared::decode_from_archive(nv); 508 } 509 m->obj_field_put(field_offset, v); 510 i += 3; 511 512 log_debug(cds, heap)(" " PTR_FORMAT " init field @ %2d = " PTR_FORMAT, p2i(k), field_offset, p2i(v)); 513 } 514 515 // Done. Java code can see the archived sub-graphs referenced from k's 516 // mirror after this point. 517 if (log_is_enabled(Info, cds, heap)) { 518 ResourceMark rm; 519 log_info(cds, heap)("initialize_from_archived_subgraph %s " PTR_FORMAT, 520 k->external_name(), p2i(k)); 521 } 522 } 523 } 524 } 525 526 class WalkOopAndArchiveClosure: public BasicOopIterateClosure { 527 int _level; 528 bool _is_closed_archive; 529 bool _record_klasses_only; 530 KlassSubGraphInfo* _subgraph_info; 531 oop _orig_referencing_obj; 532 oop _archived_referencing_obj; 533 Thread* _thread; 534 public: 535 WalkOopAndArchiveClosure(int level, 536 bool is_closed_archive, 537 bool record_klasses_only, 538 KlassSubGraphInfo* subgraph_info, 539 oop orig, oop archived, TRAPS) : 540 _level(level), _is_closed_archive(is_closed_archive), 541 _record_klasses_only(record_klasses_only), 542 _subgraph_info(subgraph_info), 543 _orig_referencing_obj(orig), _archived_referencing_obj(archived), 544 _thread(THREAD) {} 545 void do_oop(narrowOop *p) { WalkOopAndArchiveClosure::do_oop_work(p); } 546 void do_oop( oop *p) { WalkOopAndArchiveClosure::do_oop_work(p); } 547 548 protected: 549 template <class T> void do_oop_work(T *p) { 550 oop obj = RawAccess<>::oop_load(p); 551 if (!CompressedOops::is_null(obj)) { 552 assert(!HeapShared::is_archived_object(obj), 553 "original objects must not point to archived objects"); 554 555 size_t field_delta = pointer_delta(p, _orig_referencing_obj, sizeof(char)); 556 T* new_p = (T*)(cast_from_oop<address>(_archived_referencing_obj) + field_delta); 557 Thread* THREAD = _thread; 558 559 if (!_record_klasses_only && log_is_enabled(Debug, cds, heap)) { 560 ResourceMark rm; 561 log_debug(cds, heap)("(%d) %s[" SIZE_FORMAT "] ==> " PTR_FORMAT " size %d %s", _level, 562 _orig_referencing_obj->klass()->external_name(), field_delta, 563 p2i(obj), obj->size() * HeapWordSize, obj->klass()->external_name()); 564 LogTarget(Trace, cds, heap) log; 565 LogStream out(log); 566 obj->print_on(&out); 567 } 568 569 oop archived = HeapShared::archive_reachable_objects_from( 570 _level + 1, _subgraph_info, obj, _is_closed_archive, THREAD); 571 assert(archived != NULL, "VM should have exited with unarchivable objects for _level > 1"); 572 assert(HeapShared::is_archived_object(archived), "must be"); 573 574 if (!_record_klasses_only) { 575 // Update the reference in the archived copy of the referencing object. 576 log_debug(cds, heap)("(%d) updating oop @[" PTR_FORMAT "] " PTR_FORMAT " ==> " PTR_FORMAT, 577 _level, p2i(new_p), p2i(obj), p2i(archived)); 578 RawAccess<IS_NOT_NULL>::oop_store(new_p, archived); 579 } 580 } 581 } 582 }; 583 584 void HeapShared::check_closed_archive_heap_region_object(InstanceKlass* k, 585 Thread* THREAD) { 586 // Check fields in the object 587 for (JavaFieldStream fs(k); !fs.done(); fs.next()) { 588 if (!fs.access_flags().is_static()) { 589 BasicType ft = fs.field_descriptor().field_type(); 590 if (!fs.access_flags().is_final() && is_reference_type(ft)) { 591 ResourceMark rm(THREAD); 592 log_warning(cds, heap)( 593 "Please check reference field in %s instance in closed archive heap region: %s %s", 594 k->external_name(), (fs.name())->as_C_string(), 595 (fs.signature())->as_C_string()); 596 } 597 } 598 } 599 } 600 601 // (1) If orig_obj has not been archived yet, archive it. 602 // (2) If orig_obj has not been seen yet (since start_recording_subgraph() was called), 603 // trace all objects that are reachable from it, and make sure these objects are archived. 604 // (3) Record the klasses of all orig_obj and all reachable objects. 605 oop HeapShared::archive_reachable_objects_from(int level, 606 KlassSubGraphInfo* subgraph_info, 607 oop orig_obj, 608 bool is_closed_archive, 609 TRAPS) { 610 assert(orig_obj != NULL, "must be"); 611 assert(!is_archived_object(orig_obj), "sanity"); 612 613 if (!JavaClasses::is_supported_for_archiving(orig_obj)) { 614 // This object has injected fields that cannot be supported easily, so we disallow them for now. 615 // If you get an error here, you probably made a change in the JDK library that has added 616 // these objects that are referenced (directly or indirectly) by static fields. 617 ResourceMark rm; 618 log_error(cds, heap)("Cannot archive object of class %s", orig_obj->klass()->external_name()); 619 vm_exit(1); 620 } 621 622 // java.lang.Class instances cannot be included in an archived object sub-graph. We only support 623 // them as Klass::_archived_mirror because they need to be specially restored at run time. 624 // 625 // If you get an error here, you probably made a change in the JDK library that has added a Class 626 // object that is referenced (directly or indirectly) by static fields. 627 if (java_lang_Class::is_instance(orig_obj)) { 628 log_error(cds, heap)("(%d) Unknown java.lang.Class object is in the archived sub-graph", level); 629 vm_exit(1); 630 } 631 632 oop archived_obj = find_archived_heap_object(orig_obj); 633 if (java_lang_String::is_instance(orig_obj) && archived_obj != NULL) { 634 // To save time, don't walk strings that are already archived. They just contain 635 // pointers to a type array, whose klass doesn't need to be recorded. 636 return archived_obj; 637 } 638 639 if (has_been_seen_during_subgraph_recording(orig_obj)) { 640 // orig_obj has already been archived and traced. Nothing more to do. 641 return archived_obj; 642 } else { 643 set_has_been_seen_during_subgraph_recording(orig_obj); 644 } 645 646 bool record_klasses_only = (archived_obj != NULL); 647 if (archived_obj == NULL) { 648 ++_num_new_archived_objs; 649 archived_obj = archive_heap_object(orig_obj, THREAD); 650 if (archived_obj == NULL) { 651 // Skip archiving the sub-graph referenced from the current entry field. 652 ResourceMark rm; 653 log_error(cds, heap)( 654 "Cannot archive the sub-graph referenced from %s object (" 655 PTR_FORMAT ") size %d, skipped.", 656 orig_obj->klass()->external_name(), p2i(orig_obj), orig_obj->size() * HeapWordSize); 657 if (level == 1) { 658 // Don't archive a subgraph root that's too big. For archives static fields, that's OK 659 // as the Java code will take care of initializing this field dynamically. 660 return NULL; 661 } else { 662 // We don't know how to handle an object that has been archived, but some of its reachable 663 // objects cannot be archived. Bail out for now. We might need to fix this in the future if 664 // we have a real use case. 665 vm_exit(1); 666 } 667 } 668 } 669 670 assert(archived_obj != NULL, "must be"); 671 Klass *orig_k = orig_obj->klass(); 672 Klass *relocated_k = archived_obj->klass(); 673 subgraph_info->add_subgraph_object_klass(orig_k, relocated_k); 674 675 WalkOopAndArchiveClosure walker(level, is_closed_archive, record_klasses_only, 676 subgraph_info, orig_obj, archived_obj, THREAD); 677 orig_obj->oop_iterate(&walker); 678 if (is_closed_archive && orig_k->is_instance_klass()) { 679 check_closed_archive_heap_region_object(InstanceKlass::cast(orig_k), THREAD); 680 } 681 return archived_obj; 682 } 683 684 // 685 // Start from the given static field in a java mirror and archive the 686 // complete sub-graph of java heap objects that are reached directly 687 // or indirectly from the starting object by following references. 688 // Sub-graph archiving restrictions (current): 689 // 690 // - All classes of objects in the archived sub-graph (including the 691 // entry class) must be boot class only. 692 // - No java.lang.Class instance (java mirror) can be included inside 693 // an archived sub-graph. Mirror can only be the sub-graph entry object. 694 // 695 // The Java heap object sub-graph archiving process (see 696 // WalkOopAndArchiveClosure): 697 // 698 // 1) Java object sub-graph archiving starts from a given static field 699 // within a Class instance (java mirror). If the static field is a 700 // refererence field and points to a non-null java object, proceed to 701 // the next step. 702 // 703 // 2) Archives the referenced java object. If an archived copy of the 704 // current object already exists, updates the pointer in the archived 705 // copy of the referencing object to point to the current archived object. 706 // Otherwise, proceed to the next step. 707 // 708 // 3) Follows all references within the current java object and recursively 709 // archive the sub-graph of objects starting from each reference. 710 // 711 // 4) Updates the pointer in the archived copy of referencing object to 712 // point to the current archived object. 713 // 714 // 5) The Klass of the current java object is added to the list of Klasses 715 // for loading and initialzing before any object in the archived graph can 716 // be accessed at runtime. 717 // 718 void HeapShared::archive_reachable_objects_from_static_field(InstanceKlass *k, 719 const char* klass_name, 720 int field_offset, 721 const char* field_name, 722 bool is_closed_archive, 723 TRAPS) { 724 assert(DumpSharedSpaces, "dump time only"); 725 assert(k->is_shared_boot_class(), "must be boot class"); 726 727 oop m = k->java_mirror(); 728 729 KlassSubGraphInfo* subgraph_info = get_subgraph_info(k); 730 oop f = m->obj_field(field_offset); 731 732 log_debug(cds, heap)("Start archiving from: %s::%s (" PTR_FORMAT ")", klass_name, field_name, p2i(f)); 733 734 if (!CompressedOops::is_null(f)) { 735 if (log_is_enabled(Trace, cds, heap)) { 736 LogTarget(Trace, cds, heap) log; 737 LogStream out(log); 738 f->print_on(&out); 739 } 740 741 oop af = archive_reachable_objects_from(1, subgraph_info, f, 742 is_closed_archive, CHECK); 743 744 if (af == NULL) { 745 log_error(cds, heap)("Archiving failed %s::%s (some reachable objects cannot be archived)", 746 klass_name, field_name); 747 } else { 748 // Note: the field value is not preserved in the archived mirror. 749 // Record the field as a new subGraph entry point. The recorded 750 // information is restored from the archive at runtime. 751 subgraph_info->add_subgraph_entry_field(field_offset, af, is_closed_archive); 752 log_info(cds, heap)("Archived field %s::%s => " PTR_FORMAT, klass_name, field_name, p2i(af)); 753 } 754 } else { 755 // The field contains null, we still need to record the entry point, 756 // so it can be restored at runtime. 757 subgraph_info->add_subgraph_entry_field(field_offset, NULL, false); 758 } 759 } 760 761 #ifndef PRODUCT 762 class VerifySharedOopClosure: public BasicOopIterateClosure { 763 private: 764 bool _is_archived; 765 766 public: 767 VerifySharedOopClosure(bool is_archived) : _is_archived(is_archived) {} 768 769 void do_oop(narrowOop *p) { VerifySharedOopClosure::do_oop_work(p); } 770 void do_oop( oop *p) { VerifySharedOopClosure::do_oop_work(p); } 771 772 protected: 773 template <class T> void do_oop_work(T *p) { 774 oop obj = RawAccess<>::oop_load(p); 775 if (!CompressedOops::is_null(obj)) { 776 HeapShared::verify_reachable_objects_from(obj, _is_archived); 777 } 778 } 779 }; 780 781 void HeapShared::verify_subgraph_from_static_field(InstanceKlass* k, int field_offset) { 782 assert(DumpSharedSpaces, "dump time only"); 783 assert(k->is_shared_boot_class(), "must be boot class"); 784 785 oop m = k->java_mirror(); 786 oop f = m->obj_field(field_offset); 787 if (!CompressedOops::is_null(f)) { 788 verify_subgraph_from(f); 789 } 790 } 791 792 void HeapShared::verify_subgraph_from(oop orig_obj) { 793 oop archived_obj = find_archived_heap_object(orig_obj); 794 if (archived_obj == NULL) { 795 // It's OK for the root of a subgraph to be not archived. See comments in 796 // archive_reachable_objects_from(). 797 return; 798 } 799 800 // Verify that all objects reachable from orig_obj are archived. 801 init_seen_objects_table(); 802 verify_reachable_objects_from(orig_obj, false); 803 delete_seen_objects_table(); 804 805 // Note: we could also verify that all objects reachable from the archived 806 // copy of orig_obj can only point to archived objects, with: 807 // init_seen_objects_table(); 808 // verify_reachable_objects_from(archived_obj, true); 809 // init_seen_objects_table(); 810 // but that's already done in G1HeapVerifier::verify_archive_regions so we 811 // won't do it here. 812 } 813 814 void HeapShared::verify_reachable_objects_from(oop obj, bool is_archived) { 815 _num_total_verifications ++; 816 if (!has_been_seen_during_subgraph_recording(obj)) { 817 set_has_been_seen_during_subgraph_recording(obj); 818 819 if (is_archived) { 820 assert(is_archived_object(obj), "must be"); 821 assert(find_archived_heap_object(obj) == NULL, "must be"); 822 } else { 823 assert(!is_archived_object(obj), "must be"); 824 assert(find_archived_heap_object(obj) != NULL, "must be"); 825 } 826 827 VerifySharedOopClosure walker(is_archived); 828 obj->oop_iterate(&walker); 829 } 830 } 831 #endif 832 833 HeapShared::SeenObjectsTable* HeapShared::_seen_objects_table = NULL; 834 int HeapShared::_num_new_walked_objs; 835 int HeapShared::_num_new_archived_objs; 836 int HeapShared::_num_old_recorded_klasses; 837 838 int HeapShared::_num_total_subgraph_recordings = 0; 839 int HeapShared::_num_total_walked_objs = 0; 840 int HeapShared::_num_total_archived_objs = 0; 841 int HeapShared::_num_total_recorded_klasses = 0; 842 int HeapShared::_num_total_verifications = 0; 843 844 bool HeapShared::has_been_seen_during_subgraph_recording(oop obj) { 845 return _seen_objects_table->get(obj) != NULL; 846 } 847 848 void HeapShared::set_has_been_seen_during_subgraph_recording(oop obj) { 849 assert(!has_been_seen_during_subgraph_recording(obj), "sanity"); 850 _seen_objects_table->put(obj, true); 851 ++ _num_new_walked_objs; 852 } 853 854 void HeapShared::start_recording_subgraph(InstanceKlass *k, const char* class_name) { 855 log_info(cds, heap)("Start recording subgraph(s) for archived fields in %s", class_name); 856 init_seen_objects_table(); 857 _num_new_walked_objs = 0; 858 _num_new_archived_objs = 0; 859 _num_old_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses(); 860 } 861 862 void HeapShared::done_recording_subgraph(InstanceKlass *k, const char* class_name) { 863 int num_new_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses() - 864 _num_old_recorded_klasses; 865 log_info(cds, heap)("Done recording subgraph(s) for archived fields in %s: " 866 "walked %d objs, archived %d new objs, recorded %d classes", 867 class_name, _num_new_walked_objs, _num_new_archived_objs, 868 num_new_recorded_klasses); 869 870 delete_seen_objects_table(); 871 872 _num_total_subgraph_recordings ++; 873 _num_total_walked_objs += _num_new_walked_objs; 874 _num_total_archived_objs += _num_new_archived_objs; 875 _num_total_recorded_klasses += num_new_recorded_klasses; 876 } 877 878 class ArchivableStaticFieldFinder: public FieldClosure { 879 InstanceKlass* _ik; 880 Symbol* _field_name; 881 bool _found; 882 int _offset; 883 public: 884 ArchivableStaticFieldFinder(InstanceKlass* ik, Symbol* field_name) : 885 _ik(ik), _field_name(field_name), _found(false), _offset(-1) {} 886 887 virtual void do_field(fieldDescriptor* fd) { 888 if (fd->name() == _field_name) { 889 assert(!_found, "fields cannot be overloaded"); 890 assert(is_reference_type(fd->field_type()), "can archive only fields that are references"); 891 _found = true; 892 _offset = fd->offset(); 893 } 894 } 895 bool found() { return _found; } 896 int offset() { return _offset; } 897 }; 898 899 void HeapShared::init_subgraph_entry_fields(ArchivableStaticFieldInfo fields[], 900 int num, Thread* THREAD) { 901 for (int i = 0; i < num; i++) { 902 ArchivableStaticFieldInfo* info = &fields[i]; 903 TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name); 904 TempNewSymbol field_name = SymbolTable::new_symbol(info->field_name); 905 906 Klass* k = SystemDictionary::resolve_or_null(klass_name, THREAD); 907 assert(k != NULL && !HAS_PENDING_EXCEPTION, "class must exist"); 908 InstanceKlass* ik = InstanceKlass::cast(k); 909 assert(InstanceKlass::cast(ik)->is_shared_boot_class(), 910 "Only support boot classes"); 911 ik->initialize(THREAD); 912 guarantee(!HAS_PENDING_EXCEPTION, "exception in initialize"); 913 914 ArchivableStaticFieldFinder finder(ik, field_name); 915 ik->do_local_static_fields(&finder); 916 assert(finder.found(), "field must exist"); 917 918 info->klass = ik; 919 info->offset = finder.offset(); 920 } 921 } 922 923 void HeapShared::init_subgraph_entry_fields(Thread* THREAD) { 924 _dump_time_subgraph_info_table = new (ResourceObj::C_HEAP, mtClass)DumpTimeKlassSubGraphInfoTable(); 925 926 init_subgraph_entry_fields(closed_archive_subgraph_entry_fields, 927 num_closed_archive_subgraph_entry_fields, 928 THREAD); 929 init_subgraph_entry_fields(open_archive_subgraph_entry_fields, 930 num_open_archive_subgraph_entry_fields, 931 THREAD); 932 } 933 934 void HeapShared::archive_object_subgraphs(ArchivableStaticFieldInfo fields[], 935 int num, bool is_closed_archive, 936 Thread* THREAD) { 937 _num_total_subgraph_recordings = 0; 938 _num_total_walked_objs = 0; 939 _num_total_archived_objs = 0; 940 _num_total_recorded_klasses = 0; 941 _num_total_verifications = 0; 942 943 // For each class X that has one or more archived fields: 944 // [1] Dump the subgraph of each archived field 945 // [2] Create a list of all the class of the objects that can be reached 946 // by any of these static fields. 947 // At runtime, these classes are initialized before X's archived fields 948 // are restored by HeapShared::initialize_from_archived_subgraph(). 949 int i; 950 for (i = 0; i < num; ) { 951 ArchivableStaticFieldInfo* info = &fields[i]; 952 const char* klass_name = info->klass_name; 953 start_recording_subgraph(info->klass, klass_name); 954 955 // If you have specified consecutive fields of the same klass in 956 // fields[], these will be archived in the same 957 // {start_recording_subgraph ... done_recording_subgraph} pass to 958 // save time. 959 for (; i < num; i++) { 960 ArchivableStaticFieldInfo* f = &fields[i]; 961 if (f->klass_name != klass_name) { 962 break; 963 } 964 archive_reachable_objects_from_static_field(f->klass, f->klass_name, 965 f->offset, f->field_name, 966 is_closed_archive, CHECK); 967 } 968 done_recording_subgraph(info->klass, klass_name); 969 } 970 971 log_info(cds, heap)("Archived subgraph records in %s archive heap region = %d", 972 is_closed_archive ? "closed" : "open", 973 _num_total_subgraph_recordings); 974 log_info(cds, heap)(" Walked %d objects", _num_total_walked_objs); 975 log_info(cds, heap)(" Archived %d objects", _num_total_archived_objs); 976 log_info(cds, heap)(" Recorded %d klasses", _num_total_recorded_klasses); 977 978 #ifndef PRODUCT 979 for (int i = 0; i < num; i++) { 980 ArchivableStaticFieldInfo* f = &fields[i]; 981 verify_subgraph_from_static_field(f->klass, f->offset); 982 } 983 log_info(cds, heap)(" Verified %d references", _num_total_verifications); 984 #endif 985 } 986 987 // At dump-time, find the location of all the non-null oop pointers in an archived heap 988 // region. This way we can quickly relocate all the pointers without using 989 // BasicOopIterateClosure at runtime. 990 class FindEmbeddedNonNullPointers: public BasicOopIterateClosure { 991 narrowOop* _start; 992 BitMap *_oopmap; 993 int _num_total_oops; 994 int _num_null_oops; 995 public: 996 FindEmbeddedNonNullPointers(narrowOop* start, BitMap* oopmap) 997 : _start(start), _oopmap(oopmap), _num_total_oops(0), _num_null_oops(0) {} 998 999 virtual bool should_verify_oops(void) { 1000 return false; 1001 } 1002 virtual void do_oop(narrowOop* p) { 1003 _num_total_oops ++; 1004 narrowOop v = *p; 1005 if (!CompressedOops::is_null(v)) { 1006 size_t idx = p - _start; 1007 _oopmap->set_bit(idx); 1008 } else { 1009 _num_null_oops ++; 1010 } 1011 } 1012 virtual void do_oop(oop *p) { 1013 ShouldNotReachHere(); 1014 } 1015 int num_total_oops() const { return _num_total_oops; } 1016 int num_null_oops() const { return _num_null_oops; } 1017 }; 1018 1019 ResourceBitMap HeapShared::calculate_oopmap(MemRegion region) { 1020 assert(UseCompressedOops, "must be"); 1021 size_t num_bits = region.byte_size() / sizeof(narrowOop); 1022 ResourceBitMap oopmap(num_bits); 1023 1024 HeapWord* p = region.start(); 1025 HeapWord* end = region.end(); 1026 FindEmbeddedNonNullPointers finder((narrowOop*)p, &oopmap); 1027 1028 int num_objs = 0; 1029 while (p < end) { 1030 oop o = (oop)p; 1031 o->oop_iterate(&finder); 1032 p += o->size(); 1033 ++ num_objs; 1034 } 1035 1036 log_info(cds, heap)("calculate_oopmap: objects = %6d, embedded oops = %7d, nulls = %7d", 1037 num_objs, finder.num_total_oops(), finder.num_null_oops()); 1038 return oopmap; 1039 } 1040 1041 // Patch all the embedded oop pointers inside an archived heap region, 1042 // to be consistent with the runtime oop encoding. 1043 class PatchEmbeddedPointers: public BitMapClosure { 1044 narrowOop* _start; 1045 1046 public: 1047 PatchEmbeddedPointers(narrowOop* start) : _start(start) {} 1048 1049 bool do_bit(size_t offset) { 1050 narrowOop* p = _start + offset; 1051 narrowOop v = *p; 1052 assert(!CompressedOops::is_null(v), "null oops should have been filtered out at dump time"); 1053 oop o = HeapShared::decode_from_archive(v); 1054 RawAccess<IS_NOT_NULL>::oop_store(p, o); 1055 return true; 1056 } 1057 }; 1058 1059 void HeapShared::patch_archived_heap_embedded_pointers(MemRegion region, address oopmap, 1060 size_t oopmap_size_in_bits) { 1061 BitMapView bm((BitMap::bm_word_t*)oopmap, oopmap_size_in_bits); 1062 1063 #ifndef PRODUCT 1064 ResourceMark rm; 1065 ResourceBitMap checkBm = calculate_oopmap(region); 1066 assert(bm.is_same(checkBm), "sanity"); 1067 #endif 1068 1069 PatchEmbeddedPointers patcher((narrowOop*)region.start()); 1070 bm.iterate(&patcher); 1071 } 1072 1073 #endif // INCLUDE_CDS_JAVA_HEAP