1 /* 2 * Copyright (c) 2018, 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/vmSymbols.hpp" 28 #include "logging/log.hpp" 29 #include "logging/logMessage.hpp" 30 #include "logging/logStream.hpp" 31 #include "memory/heapShared.inline.hpp" 32 #include "memory/iterator.inline.hpp" 33 #include "memory/metadataFactory.hpp" 34 #include "memory/metaspaceClosure.hpp" 35 #include "memory/metaspaceShared.hpp" 36 #include "memory/resourceArea.hpp" 37 #include "oops/compressedOops.inline.hpp" 38 #include "oops/oop.inline.hpp" 39 40 #if INCLUDE_CDS_JAVA_HEAP 41 KlassSubGraphInfo* HeapShared::_subgraph_info_list = NULL; 42 int HeapShared::_num_archived_subgraph_info_records = 0; 43 Array<ArchivedKlassSubGraphInfoRecord>* HeapShared::_archived_subgraph_info_records = NULL; 44 45 // Currently there is only one class mirror (ArchivedModuleGraph) with archived 46 // sub-graphs. 47 KlassSubGraphInfo* HeapShared::find_subgraph_info(Klass* k) { 48 KlassSubGraphInfo* info = _subgraph_info_list; 49 while (info != NULL) { 50 if (info->klass() == k) { 51 return info; 52 } 53 info = info->next(); 54 } 55 return NULL; 56 } 57 58 // Get the subgraph_info for Klass k. A new subgraph_info is created if 59 // there is no existing one for k. The subgraph_info records the relocated 60 // Klass* of the original k. 61 KlassSubGraphInfo* HeapShared::get_subgraph_info(Klass* k) { 62 Klass* relocated_k = MetaspaceShared::get_relocated_klass(k); 63 KlassSubGraphInfo* info = find_subgraph_info(relocated_k); 64 if (info != NULL) { 65 return info; 66 } 67 68 info = new KlassSubGraphInfo(relocated_k, _subgraph_info_list); 69 _subgraph_info_list = info; 70 return info; 71 } 72 73 address HeapShared::_narrow_oop_base; 74 int HeapShared::_narrow_oop_shift; 75 76 int HeapShared::num_of_subgraph_infos() { 77 int num = 0; 78 KlassSubGraphInfo* info = _subgraph_info_list; 79 while (info != NULL) { 80 num ++; 81 info = info->next(); 82 } 83 return num; 84 } 85 86 // Add an entry field to the current KlassSubGraphInfo. 87 void KlassSubGraphInfo::add_subgraph_entry_field(int static_field_offset, oop v) { 88 assert(DumpSharedSpaces, "dump time only"); 89 if (_subgraph_entry_fields == NULL) { 90 _subgraph_entry_fields = 91 new(ResourceObj::C_HEAP, mtClass) GrowableArray<juint>(10, true); 92 } 93 _subgraph_entry_fields->append((juint)static_field_offset); 94 _subgraph_entry_fields->append(CompressedOops::encode(v)); 95 } 96 97 // Add the Klass* for an object in the current KlassSubGraphInfo's subgraphs. 98 // Only objects of boot classes can be included in sub-graph. 99 void KlassSubGraphInfo::add_subgraph_object_klass(Klass* orig_k, Klass *relocated_k) { 100 assert(DumpSharedSpaces, "dump time only"); 101 assert(relocated_k == MetaspaceShared::get_relocated_klass(orig_k), 102 "must be the relocated Klass in the shared space"); 103 104 if (_subgraph_object_klasses == NULL) { 105 _subgraph_object_klasses = 106 new(ResourceObj::C_HEAP, mtClass) GrowableArray<Klass*>(50, true); 107 } 108 109 assert(relocated_k->is_shared(), "must be a shared class"); 110 if (relocated_k->is_instance_klass()) { 111 assert(InstanceKlass::cast(relocated_k)->is_shared_boot_class(), 112 "must be boot class"); 113 // SystemDictionary::xxx_klass() are not updated, need to check 114 // the original Klass* 115 if (orig_k == SystemDictionary::String_klass() || 116 orig_k == SystemDictionary::Object_klass()) { 117 // Initialized early during VM initialization. No need to be added 118 // to the sub-graph object class list. 119 return; 120 } 121 } else if (relocated_k->is_objArray_klass()) { 122 Klass* abk = ObjArrayKlass::cast(relocated_k)->bottom_klass(); 123 if (abk->is_instance_klass()) { 124 assert(InstanceKlass::cast(abk)->is_shared_boot_class(), 125 "must be boot class"); 126 } 127 if (relocated_k == Universe::objectArrayKlassObj()) { 128 // Initialized early during Universe::genesis. No need to be added 129 // to the list. 130 return; 131 } 132 } else { 133 assert(relocated_k->is_typeArray_klass(), "must be"); 134 // Primitive type arrays are created early during Universe::genesis. 135 return; 136 } 137 138 _subgraph_object_klasses->append_if_missing(relocated_k); 139 } 140 141 // Initialize an archived subgraph_info_record from the given KlassSubGraphInfo. 142 void ArchivedKlassSubGraphInfoRecord::init(KlassSubGraphInfo* info) { 143 _k = info->klass(); 144 _next = NULL; 145 _entry_field_records = NULL; 146 _subgraph_klasses = NULL; 147 148 // populate the entry fields 149 GrowableArray<juint>* entry_fields = info->subgraph_entry_fields(); 150 if (entry_fields != NULL) { 151 int num_entry_fields = entry_fields->length(); 152 assert(num_entry_fields % 2 == 0, "sanity"); 153 _entry_field_records = 154 MetaspaceShared::new_ro_array<juint>(num_entry_fields); 155 for (int i = 0 ; i < num_entry_fields; i++) { 156 _entry_field_records->at_put(i, entry_fields->at(i)); 157 } 158 } 159 160 // the Klasses of the objects in the sub-graphs 161 GrowableArray<Klass*>* subgraph_klasses = info->subgraph_object_klasses(); 162 if (subgraph_klasses != NULL) { 163 int num_subgraphs_klasses = subgraph_klasses->length(); 164 _subgraph_klasses = 165 MetaspaceShared::new_ro_array<Klass*>(num_subgraphs_klasses); 166 for (int i = 0; i < num_subgraphs_klasses; i++) { 167 Klass* subgraph_k = subgraph_klasses->at(i); 168 if (log_is_enabled(Info, cds, heap)) { 169 ResourceMark rm; 170 log_info(cds, heap)( 171 "Archived object klass (%d): %s in %s sub-graphs", 172 i, subgraph_k->external_name(), _k->external_name()); 173 } 174 _subgraph_klasses->at_put(i, subgraph_k); 175 } 176 } 177 } 178 179 // Build the records of archived subgraph infos, which include: 180 // - Entry points to all subgraphs from the containing class mirror. The entry 181 // points are static fields in the mirror. For each entry point, the field 182 // offset and value are recorded in the sub-graph info. The value are stored 183 // back to the corresponding field at runtime. 184 // - A list of klasses that need to be loaded/initialized before archived 185 // java object sub-graph can be accessed at runtime. 186 // 187 // The records are saved in the archive file and reloaded at runtime. Currently 188 // there is only one class mirror (ArchivedModuleGraph) with archived sub-graphs. 189 // 190 // Layout of the archived subgraph info records: 191 // 192 // records_size | num_records | records* 193 // ArchivedKlassSubGraphInfoRecord | entry_fields | subgraph_object_klasses 194 size_t HeapShared::build_archived_subgraph_info_records(int num_records) { 195 // remember the start address 196 char* start_p = MetaspaceShared::read_only_space_top(); 197 198 // now populate the archived subgraph infos, which will be saved in the 199 // archive file 200 _archived_subgraph_info_records = 201 MetaspaceShared::new_ro_array<ArchivedKlassSubGraphInfoRecord>(num_records); 202 KlassSubGraphInfo* info = _subgraph_info_list; 203 int i = 0; 204 while (info != NULL) { 205 assert(i < _archived_subgraph_info_records->length(), "sanity"); 206 ArchivedKlassSubGraphInfoRecord* record = 207 _archived_subgraph_info_records->adr_at(i); 208 record->init(info); 209 info = info->next(); 210 i ++; 211 } 212 213 // _subgraph_info_list is no longer needed 214 delete _subgraph_info_list; 215 _subgraph_info_list = NULL; 216 217 char* end_p = MetaspaceShared::read_only_space_top(); 218 size_t records_size = end_p - start_p; 219 return records_size; 220 } 221 222 // Write the subgraph info records in the shared _ro region 223 void HeapShared::write_archived_subgraph_infos() { 224 assert(DumpSharedSpaces, "dump time only"); 225 226 Array<intptr_t>* records_header = MetaspaceShared::new_ro_array<intptr_t>(3); 227 228 _num_archived_subgraph_info_records = num_of_subgraph_infos(); 229 size_t records_size = build_archived_subgraph_info_records( 230 _num_archived_subgraph_info_records); 231 232 // Now write the header information: 233 // records_size, num_records, _archived_subgraph_info_records 234 assert(records_header != NULL, "sanity"); 235 intptr_t* p = (intptr_t*)(records_header->data()); 236 *p = (intptr_t)records_size; 237 p ++; 238 *p = (intptr_t)_num_archived_subgraph_info_records; 239 p ++; 240 *p = (intptr_t)_archived_subgraph_info_records; 241 } 242 243 char* HeapShared::read_archived_subgraph_infos(char* buffer) { 244 Array<intptr_t>* records_header = (Array<intptr_t>*)buffer; 245 intptr_t* p = (intptr_t*)(records_header->data()); 246 size_t records_size = (size_t)(*p); 247 p ++; 248 _num_archived_subgraph_info_records = *p; 249 p ++; 250 _archived_subgraph_info_records = 251 (Array<ArchivedKlassSubGraphInfoRecord>*)(*p); 252 253 buffer = (char*)_archived_subgraph_info_records + records_size; 254 return buffer; 255 } 256 257 void HeapShared::initialize_from_archived_subgraph(Klass* k) { 258 if (!MetaspaceShared::open_archive_heap_region_mapped()) { 259 return; // nothing to do 260 } 261 262 if (_num_archived_subgraph_info_records == 0) { 263 return; // no subgraph info records 264 } 265 266 // Initialize from archived data. Currently only ArchivedModuleGraph 267 // has archived object subgraphs, which is used during VM initialization 268 // time when bootstraping the system modules. No lock is needed. 269 Thread* THREAD = Thread::current(); 270 for (int i = 0; i < _archived_subgraph_info_records->length(); i++) { 271 ArchivedKlassSubGraphInfoRecord* record = _archived_subgraph_info_records->adr_at(i); 272 if (record->klass() == k) { 273 int i; 274 // Found the archived subgraph info record for the requesting klass. 275 // Load/link/initialize the klasses of the objects in the subgraph. 276 // NULL class loader is used. 277 Array<Klass*>* klasses = record->subgraph_klasses(); 278 if (klasses != NULL) { 279 for (i = 0; i < klasses->length(); i++) { 280 Klass* obj_k = klasses->at(i); 281 Klass* resolved_k = SystemDictionary::resolve_or_null( 282 (obj_k)->name(), THREAD); 283 if (resolved_k != obj_k) { 284 return; 285 } 286 if ((obj_k)->is_instance_klass()) { 287 InstanceKlass* ik = InstanceKlass::cast(obj_k); 288 ik->initialize(THREAD); 289 } else if ((obj_k)->is_objArray_klass()) { 290 ObjArrayKlass* oak = ObjArrayKlass::cast(obj_k); 291 oak->initialize(THREAD); 292 } 293 } 294 } 295 296 if (HAS_PENDING_EXCEPTION) { 297 CLEAR_PENDING_EXCEPTION; 298 // None of the field value will be set if there was an exception. 299 // The java code will not see any of the archived objects in the 300 // subgraphs referenced from k in this case. 301 return; 302 } 303 304 // Load the subgraph entry fields from the record and store them back to 305 // the corresponding fields within the mirror. 306 oop m = k->java_mirror(); 307 Array<juint>* entry_field_records = record->entry_field_records(); 308 if (entry_field_records != NULL) { 309 int efr_len = entry_field_records->length(); 310 assert(efr_len % 2 == 0, "sanity"); 311 for (i = 0; i < efr_len;) { 312 int field_offset = entry_field_records->at(i); 313 // The object refereced by the field becomes 'known' by GC from this 314 // point. All objects in the subgraph reachable from the object are 315 // also 'known' by GC. 316 oop v = MetaspaceShared::materialize_archived_object( 317 entry_field_records->at(i+1)); 318 m->obj_field_put(field_offset, v); 319 i += 2; 320 } 321 } 322 323 // Done. Java code can see the archived sub-graphs referenced from k's 324 // mirror after this point. 325 return; 326 } 327 } 328 } 329 330 class WalkOopAndArchiveClosure: public BasicOopIterateClosure { 331 int _level; 332 KlassSubGraphInfo* _subgraph_info; 333 oop _orig_referencing_obj; 334 oop _archived_referencing_obj; 335 public: 336 WalkOopAndArchiveClosure(int level, KlassSubGraphInfo* subgraph_info, 337 oop orig, oop archived) : _level(level), 338 _subgraph_info(subgraph_info), 339 _orig_referencing_obj(orig), 340 _archived_referencing_obj(archived) {} 341 void do_oop(narrowOop *p) { WalkOopAndArchiveClosure::do_oop_work(p); } 342 void do_oop( oop *p) { WalkOopAndArchiveClosure::do_oop_work(p); } 343 344 protected: 345 template <class T> void do_oop_work(T *p) { 346 oop obj = RawAccess<>::oop_load(p); 347 if (!CompressedOops::is_null(obj)) { 348 // A java.lang.Class instance can not be included in an archived 349 // object sub-graph. 350 if (java_lang_Class::is_instance(obj)) { 351 tty->print("Unknown java.lang.Class object is in the archived sub-graph\n"); 352 vm_exit(1); 353 } 354 355 LogTarget(Debug, cds, heap) log; 356 LogStream ls(log); 357 outputStream* out = &ls; 358 { 359 ResourceMark rm; 360 log.print("(%d) %s <--- referenced from: %s", 361 _level, obj->klass()->external_name(), 362 CompressedOops::is_null(_orig_referencing_obj) ? 363 "" : _orig_referencing_obj->klass()->external_name()); 364 obj->print_on(out); 365 } 366 367 if (MetaspaceShared::is_archive_object(obj)) { 368 // The current oop is an archived oop, nothing needs to be done 369 log.print("--- object is already archived ---"); 370 return; 371 } 372 373 size_t field_delta = pointer_delta( 374 p, _orig_referencing_obj, sizeof(char)); 375 T* new_p = (T*)(address(_archived_referencing_obj) + field_delta); 376 oop archived = MetaspaceShared::find_archived_heap_object(obj); 377 if (archived != NULL) { 378 // There is an archived copy existing, update reference to point 379 // to the archived copy 380 RawAccess<IS_NOT_NULL>::oop_store(new_p, archived); 381 log.print( 382 "--- found existing archived copy, store archived " PTR_FORMAT " in " PTR_FORMAT, 383 p2i(archived), p2i(new_p)); 384 return; 385 } 386 387 int l = _level + 1; 388 Thread* THREAD = Thread::current(); 389 // Archive the current oop before iterating through its references 390 archived = MetaspaceShared::archive_heap_object(obj, THREAD); 391 assert(MetaspaceShared::is_archive_object(archived), "must be archived"); 392 log.print("=== archiving oop " PTR_FORMAT " ==> " PTR_FORMAT, 393 p2i(obj), p2i(archived)); 394 395 // Following the references in the current oop and archive any 396 // encountered objects during the process 397 WalkOopAndArchiveClosure walker(l, _subgraph_info, obj, archived); 398 obj->oop_iterate(&walker); 399 400 // Update the reference in the archived copy of the referencing object 401 RawAccess<IS_NOT_NULL>::oop_store(new_p, archived); 402 log.print("=== store archived " PTR_FORMAT " in " PTR_FORMAT, 403 p2i(archived), p2i(new_p)); 404 405 // Add the klass to the list of classes that need to be loaded before 406 // module system initialization 407 Klass *orig_k = obj->klass(); 408 Klass *relocated_k = archived->klass(); 409 _subgraph_info->add_subgraph_object_klass(orig_k, relocated_k); 410 } 411 } 412 }; 413 414 // 415 // Start from the given static field in a java mirror and archive the 416 // complete sub-graph of java heap objects that are reached directly 417 // or indirectly from the starting object by following references. 418 // Currently, only ArchivedModuleGraph class instance (mirror) has archived 419 // object subgraphs. Sub-graph archiving restrictions (current): 420 // 421 // - All classes of objects in the archived sub-graph (including the 422 // entry class) must be boot class only. 423 // - No java.lang.Class instance (java mirror) can be included inside 424 // an archived sub-graph. Mirror can only be the sub-graph entry object. 425 // 426 // The Java heap object sub-graph archiving process (see 427 // WalkOopAndArchiveClosure): 428 // 429 // 1) Java object sub-graph archiving starts from a given static field 430 // within a Class instance (java mirror). If the static field is a 431 // refererence field and points to a non-null java object, proceed to 432 // the next step. 433 // 434 // 2) Archives the referenced java object. If an archived copy of the 435 // current object already exists, updates the pointer in the archived 436 // copy of the referencing object to point to the current archived object. 437 // Otherwise, proceed to the next step. 438 // 439 // 3) Follows all references within the current java object and recursively 440 // archive the sub-graph of objects starting from each reference. 441 // 442 // 4) Updates the pointer in the archived copy of referencing object to 443 // point to the current archived object. 444 // 445 // 5) The Klass of the current java object is added to the list of Klasses 446 // for loading and initialzing before any object in the archived graph can 447 // be accessed at runtime. 448 // 449 void HeapShared::archive_reachable_objects_from_static_field(Klass *k, 450 int field_offset, 451 BasicType field_type, 452 TRAPS) { 453 assert(DumpSharedSpaces, "dump time only"); 454 assert(k->is_instance_klass(), "sanity"); 455 assert(InstanceKlass::cast(k)->is_shared_boot_class(), 456 "must be boot class"); 457 458 oop m = k->java_mirror(); 459 oop archived_m = MetaspaceShared::find_archived_heap_object(m); 460 if (CompressedOops::is_null(archived_m)) { 461 return; 462 } 463 464 if (field_type == T_OBJECT) { 465 // obtain k's subGraph Info 466 KlassSubGraphInfo* subgraph_info = get_subgraph_info(k); 467 468 // get the object referenced by the field 469 oop f = m->obj_field(field_offset); 470 if (!CompressedOops::is_null(f)) { 471 LogTarget(Debug, cds, heap) log; 472 LogStream ls(log); 473 outputStream* out = &ls; 474 log.print("Start from: "); 475 f->print_on(out); 476 477 // get the archived copy of the field referenced object 478 oop af = MetaspaceShared::archive_heap_object(f, THREAD); 479 if (!MetaspaceShared::is_archive_object(f)) { 480 WalkOopAndArchiveClosure walker(1, subgraph_info, f, af); 481 f->oop_iterate(&walker); 482 } 483 484 // The field value is not preserved in the archived mirror. 485 // Record the field as a new subGraph entry point. The recorded 486 // information is restored from the archive at runtime. 487 subgraph_info->add_subgraph_entry_field(field_offset, af); 488 Klass *relocated_k = af->klass(); 489 Klass *orig_k = f->klass(); 490 subgraph_info->add_subgraph_object_klass(orig_k, relocated_k); 491 } else { 492 // The field contains null, we still need to record the entry point, 493 // so it can be restored at runtime. 494 subgraph_info->add_subgraph_entry_field(field_offset, NULL); 495 } 496 } else { 497 ShouldNotReachHere(); 498 } 499 } 500 501 #define do_module_object_graph(archive_object_graph_do) \ 502 archive_object_graph_do(SystemDictionary::ArchivedModuleGraph_klass(), jdk_internal_module_ArchivedModuleGraph::archivedSystemModules_offset(), T_OBJECT, CHECK); \ 503 archive_object_graph_do(SystemDictionary::ArchivedModuleGraph_klass(), jdk_internal_module_ArchivedModuleGraph::archivedModuleFinder_offset(), T_OBJECT, CHECK); \ 504 archive_object_graph_do(SystemDictionary::ArchivedModuleGraph_klass(), jdk_internal_module_ArchivedModuleGraph::archivedMainModule_offset(), T_OBJECT, CHECK) 505 506 void HeapShared::archive_module_graph_objects(Thread* THREAD) { 507 do_module_object_graph(archive_reachable_objects_from_static_field); 508 } 509 510 void HeapShared::init_narrow_oop_decoding(address base, int shift) { 511 _narrow_oop_base = base; 512 _narrow_oop_shift = shift; 513 } 514 515 #endif // INCLUDE_CDS_JAVA_HEAP