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((HeapWord*)obj, (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_object_is_in_heap(p, obj);
553 assert(!HeapShared::is_archived_object(obj),
554 "original objects must not point to archived objects");
555
556 size_t field_delta = pointer_delta(p, _orig_referencing_obj, sizeof(char));
557 T* new_p = (T*)(address(_archived_referencing_obj) + field_delta);
558 Thread* THREAD = _thread;
559
560 if (!_record_klasses_only && log_is_enabled(Debug, cds, heap)) {
561 ResourceMark rm;
562 log_debug(cds, heap)("(%d) %s[" SIZE_FORMAT "] ==> " PTR_FORMAT " size %d %s", _level,
563 _orig_referencing_obj->klass()->external_name(), field_delta,
564 p2i(obj), obj->size() * HeapWordSize, obj->klass()->external_name());
565 LogTarget(Trace, cds, heap) log;
566 LogStream out(log);
567 obj->print_on(&out);
568 }
569
570 oop archived = HeapShared::archive_reachable_objects_from(
571 _level + 1, _subgraph_info, obj, _is_closed_archive, THREAD);
572 assert(archived != NULL, "VM should have exited with unarchivable objects for _level > 1");
573 assert(HeapShared::is_archived_object(archived), "must be");
574
575 if (!_record_klasses_only) {
576 // Update the reference in the archived copy of the referencing object.
577 log_debug(cds, heap)("(%d) updating oop @[" PTR_FORMAT "] " PTR_FORMAT " ==> " PTR_FORMAT,
578 _level, p2i(new_p), p2i(obj), p2i(archived));
579 RawAccess<IS_NOT_NULL>::oop_store(new_p, archived);
580 }
581 }
582 }
583 };
584
585 void HeapShared::check_closed_archive_heap_region_object(InstanceKlass* k,
586 Thread* THREAD) {
587 // Check fields in the object
588 for (JavaFieldStream fs(k); !fs.done(); fs.next()) {
589 if (!fs.access_flags().is_static()) {
590 BasicType ft = fs.field_descriptor().field_type();
591 if (!fs.access_flags().is_final() && is_reference_type(ft)) {
592 ResourceMark rm(THREAD);
593 log_warning(cds, heap)(
594 "Please check reference field in %s instance in closed archive heap region: %s %s",
595 k->external_name(), (fs.name())->as_C_string(),
596 (fs.signature())->as_C_string());
597 }
598 }
599 }
600 }
601
602 // (1) If orig_obj has not been archived yet, archive it.
603 // (2) If orig_obj has not been seen yet (since start_recording_subgraph() was called),
604 // trace all objects that are reachable from it, and make sure these objects are archived.
605 // (3) Record the klasses of all orig_obj and all reachable objects.
606 oop HeapShared::archive_reachable_objects_from(int level,
607 KlassSubGraphInfo* subgraph_info,
608 oop orig_obj,
609 bool is_closed_archive,
610 TRAPS) {
611 assert(orig_obj != NULL, "must be");
612 assert(!is_archived_object(orig_obj), "sanity");
613
614 if (!JavaClasses::is_supported_for_archiving(orig_obj)) {
615 // This object has injected fields that cannot be supported easily, so we disallow them for now.
616 // If you get an error here, you probably made a change in the JDK library that has added
617 // these objects that are referenced (directly or indirectly) by static fields.
618 ResourceMark rm;
619 log_error(cds, heap)("Cannot archive object of class %s", orig_obj->klass()->external_name());
620 vm_exit(1);
621 }
622
623 // java.lang.Class instances cannot be included in an archived object sub-graph. We only support
624 // them as Klass::_archived_mirror because they need to be specially restored at run time.
625 //
626 // If you get an error here, you probably made a change in the JDK library that has added a Class
627 // object that is referenced (directly or indirectly) by static fields.
628 if (java_lang_Class::is_instance(orig_obj)) {
629 log_error(cds, heap)("(%d) Unknown java.lang.Class object is in the archived sub-graph", level);
630 vm_exit(1);
631 }
632
633 oop archived_obj = find_archived_heap_object(orig_obj);
634 if (java_lang_String::is_instance(orig_obj) && archived_obj != NULL) {
635 // To save time, don't walk strings that are already archived. They just contain
636 // pointers to a type array, whose klass doesn't need to be recorded.
637 return archived_obj;
638 }
639
640 if (has_been_seen_during_subgraph_recording(orig_obj)) {
641 // orig_obj has already been archived and traced. Nothing more to do.
642 return archived_obj;
643 } else {
644 set_has_been_seen_during_subgraph_recording(orig_obj);
645 }
646
647 bool record_klasses_only = (archived_obj != NULL);
648 if (archived_obj == NULL) {
649 ++_num_new_archived_objs;
650 archived_obj = archive_heap_object(orig_obj, THREAD);
651 if (archived_obj == NULL) {
652 // Skip archiving the sub-graph referenced from the current entry field.
653 ResourceMark rm;
654 log_error(cds, heap)(
655 "Cannot archive the sub-graph referenced from %s object ("
656 PTR_FORMAT ") size %d, skipped.",
657 orig_obj->klass()->external_name(), p2i(orig_obj), orig_obj->size() * HeapWordSize);
658 if (level == 1) {
659 // Don't archive a subgraph root that's too big. For archives static fields, that's OK
660 // as the Java code will take care of initializing this field dynamically.
661 return NULL;
662 } else {
663 // We don't know how to handle an object that has been archived, but some of its reachable
664 // objects cannot be archived. Bail out for now. We might need to fix this in the future if
665 // we have a real use case.
666 vm_exit(1);
667 }
668 }
669 }
670
671 assert(archived_obj != NULL, "must be");
672 Klass *orig_k = orig_obj->klass();
673 Klass *relocated_k = archived_obj->klass();
674 subgraph_info->add_subgraph_object_klass(orig_k, relocated_k);
675
676 WalkOopAndArchiveClosure walker(level, is_closed_archive, record_klasses_only,
677 subgraph_info, orig_obj, archived_obj, THREAD);
678 orig_obj->oop_iterate(&walker);
679 if (is_closed_archive && orig_k->is_instance_klass()) {
680 check_closed_archive_heap_region_object(InstanceKlass::cast(orig_k), THREAD);
681 }
682 return archived_obj;
683 }
684
685 //
686 // Start from the given static field in a java mirror and archive the
687 // complete sub-graph of java heap objects that are reached directly
688 // or indirectly from the starting object by following references.
689 // Sub-graph archiving restrictions (current):
690 //
691 // - All classes of objects in the archived sub-graph (including the
692 // entry class) must be boot class only.
693 // - No java.lang.Class instance (java mirror) can be included inside
694 // an archived sub-graph. Mirror can only be the sub-graph entry object.
695 //
696 // The Java heap object sub-graph archiving process (see
697 // WalkOopAndArchiveClosure):
698 //
699 // 1) Java object sub-graph archiving starts from a given static field
700 // within a Class instance (java mirror). If the static field is a
701 // refererence field and points to a non-null java object, proceed to
702 // the next step.
703 //
704 // 2) Archives the referenced java object. If an archived copy of the
705 // current object already exists, updates the pointer in the archived
706 // copy of the referencing object to point to the current archived object.
707 // Otherwise, proceed to the next step.
708 //
709 // 3) Follows all references within the current java object and recursively
710 // archive the sub-graph of objects starting from each reference.
711 //
712 // 4) Updates the pointer in the archived copy of referencing object to
713 // point to the current archived object.
714 //
715 // 5) The Klass of the current java object is added to the list of Klasses
716 // for loading and initialzing before any object in the archived graph can
717 // be accessed at runtime.
718 //
719 void HeapShared::archive_reachable_objects_from_static_field(InstanceKlass *k,
720 const char* klass_name,
721 int field_offset,
722 const char* field_name,
723 bool is_closed_archive,
724 TRAPS) {
725 assert(DumpSharedSpaces, "dump time only");
726 assert(k->is_shared_boot_class(), "must be boot class");
727
728 oop m = k->java_mirror();
729
730 KlassSubGraphInfo* subgraph_info = get_subgraph_info(k);
731 oop f = m->obj_field(field_offset);
732
733 log_debug(cds, heap)("Start archiving from: %s::%s (" PTR_FORMAT ")", klass_name, field_name, p2i(f));
734
735 if (!CompressedOops::is_null(f)) {
736 if (log_is_enabled(Trace, cds, heap)) {
737 LogTarget(Trace, cds, heap) log;
738 LogStream out(log);
739 f->print_on(&out);
740 }
741
742 oop af = archive_reachable_objects_from(1, subgraph_info, f,
743 is_closed_archive, CHECK);
744
745 if (af == NULL) {
746 log_error(cds, heap)("Archiving failed %s::%s (some reachable objects cannot be archived)",
747 klass_name, field_name);
748 } else {
749 // Note: the field value is not preserved in the archived mirror.
750 // Record the field as a new subGraph entry point. The recorded
751 // information is restored from the archive at runtime.
752 subgraph_info->add_subgraph_entry_field(field_offset, af, is_closed_archive);
753 log_info(cds, heap)("Archived field %s::%s => " PTR_FORMAT, klass_name, field_name, p2i(af));
754 }
755 } else {
756 // The field contains null, we still need to record the entry point,
757 // so it can be restored at runtime.
758 subgraph_info->add_subgraph_entry_field(field_offset, NULL, false);
759 }
760 }
761
762 #ifndef PRODUCT
763 class VerifySharedOopClosure: public BasicOopIterateClosure {
764 private:
765 bool _is_archived;
766
767 public:
768 VerifySharedOopClosure(bool is_archived) : _is_archived(is_archived) {}
769
770 void do_oop(narrowOop *p) { VerifySharedOopClosure::do_oop_work(p); }
771 void do_oop( oop *p) { VerifySharedOopClosure::do_oop_work(p); }
772
773 protected:
774 template <class T> void do_oop_work(T *p) {
775 oop obj = RawAccess<>::oop_load(p);
776 if (!CompressedOops::is_null(obj)) {
777 assert_object_is_in_heap(p, obj);
778
779 HeapShared::verify_reachable_objects_from(obj, _is_archived);
780 }
781 }
782 };
783
784 void HeapShared::verify_subgraph_from_static_field(InstanceKlass* k, int field_offset) {
785 assert(DumpSharedSpaces, "dump time only");
786 assert(k->is_shared_boot_class(), "must be boot class");
787
788 oop m = k->java_mirror();
789 oop f = m->obj_field(field_offset);
790 if (!CompressedOops::is_null(f)) {
791 verify_subgraph_from(f);
792 }
793 }
794
795 void HeapShared::verify_subgraph_from(oop orig_obj) {
796 oop archived_obj = find_archived_heap_object(orig_obj);
797 if (archived_obj == NULL) {
798 // It's OK for the root of a subgraph to be not archived. See comments in
799 // archive_reachable_objects_from().
800 return;
801 }
802
803 // Verify that all objects reachable from orig_obj are archived.
804 init_seen_objects_table();
805 verify_reachable_objects_from(orig_obj, false);
806 delete_seen_objects_table();
807
808 // Note: we could also verify that all objects reachable from the archived
809 // copy of orig_obj can only point to archived objects, with:
810 // init_seen_objects_table();
811 // verify_reachable_objects_from(archived_obj, true);
812 // init_seen_objects_table();
813 // but that's already done in G1HeapVerifier::verify_archive_regions so we
814 // won't do it here.
815 }
816
817 void HeapShared::verify_reachable_objects_from(oop obj, bool is_archived) {
818 _num_total_verifications ++;
819 if (!has_been_seen_during_subgraph_recording(obj)) {
820 set_has_been_seen_during_subgraph_recording(obj);
821
822 if (is_archived) {
823 assert(is_archived_object(obj), "must be");
824 assert(find_archived_heap_object(obj) == NULL, "must be");
825 } else {
826 assert(!is_archived_object(obj), "must be");
827 assert(find_archived_heap_object(obj) != NULL, "must be");
828 }
829
830 VerifySharedOopClosure walker(is_archived);
831 obj->oop_iterate(&walker);
832 }
833 }
834 #endif
835
836 HeapShared::SeenObjectsTable* HeapShared::_seen_objects_table = NULL;
837 int HeapShared::_num_new_walked_objs;
838 int HeapShared::_num_new_archived_objs;
839 int HeapShared::_num_old_recorded_klasses;
840
841 int HeapShared::_num_total_subgraph_recordings = 0;
842 int HeapShared::_num_total_walked_objs = 0;
843 int HeapShared::_num_total_archived_objs = 0;
844 int HeapShared::_num_total_recorded_klasses = 0;
845 int HeapShared::_num_total_verifications = 0;
846
847 bool HeapShared::has_been_seen_during_subgraph_recording(oop obj) {
848 return _seen_objects_table->get(obj) != NULL;
849 }
850
851 void HeapShared::set_has_been_seen_during_subgraph_recording(oop obj) {
852 assert(!has_been_seen_during_subgraph_recording(obj), "sanity");
853 _seen_objects_table->put(obj, true);
854 ++ _num_new_walked_objs;
855 }
856
857 void HeapShared::start_recording_subgraph(InstanceKlass *k, const char* class_name) {
858 log_info(cds, heap)("Start recording subgraph(s) for archived fields in %s", class_name);
859 init_seen_objects_table();
860 _num_new_walked_objs = 0;
861 _num_new_archived_objs = 0;
862 _num_old_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses();
863 }
864
865 void HeapShared::done_recording_subgraph(InstanceKlass *k, const char* class_name) {
866 int num_new_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses() -
867 _num_old_recorded_klasses;
868 log_info(cds, heap)("Done recording subgraph(s) for archived fields in %s: "
869 "walked %d objs, archived %d new objs, recorded %d classes",
870 class_name, _num_new_walked_objs, _num_new_archived_objs,
871 num_new_recorded_klasses);
872
873 delete_seen_objects_table();
874
875 _num_total_subgraph_recordings ++;
876 _num_total_walked_objs += _num_new_walked_objs;
877 _num_total_archived_objs += _num_new_archived_objs;
878 _num_total_recorded_klasses += num_new_recorded_klasses;
879 }
880
881 class ArchivableStaticFieldFinder: public FieldClosure {
882 InstanceKlass* _ik;
883 Symbol* _field_name;
884 bool _found;
885 int _offset;
886 public:
887 ArchivableStaticFieldFinder(InstanceKlass* ik, Symbol* field_name) :
888 _ik(ik), _field_name(field_name), _found(false), _offset(-1) {}
889
890 virtual void do_field(fieldDescriptor* fd) {
891 if (fd->name() == _field_name) {
892 assert(!_found, "fields cannot be overloaded");
893 assert(is_reference_type(fd->field_type()), "can archive only fields that are references");
894 _found = true;
895 _offset = fd->offset();
896 }
897 }
898 bool found() { return _found; }
899 int offset() { return _offset; }
900 };
901
902 void HeapShared::init_subgraph_entry_fields(ArchivableStaticFieldInfo fields[],
903 int num, Thread* THREAD) {
904 for (int i = 0; i < num; i++) {
905 ArchivableStaticFieldInfo* info = &fields[i];
906 TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name);
907 TempNewSymbol field_name = SymbolTable::new_symbol(info->field_name);
908
909 Klass* k = SystemDictionary::resolve_or_null(klass_name, THREAD);
910 assert(k != NULL && !HAS_PENDING_EXCEPTION, "class must exist");
911 InstanceKlass* ik = InstanceKlass::cast(k);
912 assert(InstanceKlass::cast(ik)->is_shared_boot_class(),
913 "Only support boot classes");
914 ik->initialize(THREAD);
915 guarantee(!HAS_PENDING_EXCEPTION, "exception in initialize");
916
917 ArchivableStaticFieldFinder finder(ik, field_name);
918 ik->do_local_static_fields(&finder);
919 assert(finder.found(), "field must exist");
920
921 info->klass = ik;
922 info->offset = finder.offset();
923 }
924 }
925
926 void HeapShared::init_subgraph_entry_fields(Thread* THREAD) {
927 _dump_time_subgraph_info_table = new (ResourceObj::C_HEAP, mtClass)DumpTimeKlassSubGraphInfoTable();
928
929 init_subgraph_entry_fields(closed_archive_subgraph_entry_fields,
930 num_closed_archive_subgraph_entry_fields,
931 THREAD);
932 init_subgraph_entry_fields(open_archive_subgraph_entry_fields,
933 num_open_archive_subgraph_entry_fields,
934 THREAD);
935 }
936
937 void HeapShared::archive_object_subgraphs(ArchivableStaticFieldInfo fields[],
938 int num, bool is_closed_archive,
939 Thread* THREAD) {
940 _num_total_subgraph_recordings = 0;
941 _num_total_walked_objs = 0;
942 _num_total_archived_objs = 0;
943 _num_total_recorded_klasses = 0;
944 _num_total_verifications = 0;
945
946 // For each class X that has one or more archived fields:
947 // [1] Dump the subgraph of each archived field
948 // [2] Create a list of all the class of the objects that can be reached
949 // by any of these static fields.
950 // At runtime, these classes are initialized before X's archived fields
951 // are restored by HeapShared::initialize_from_archived_subgraph().
952 int i;
953 for (i = 0; i < num; ) {
954 ArchivableStaticFieldInfo* info = &fields[i];
955 const char* klass_name = info->klass_name;
956 start_recording_subgraph(info->klass, klass_name);
957
958 // If you have specified consecutive fields of the same klass in
959 // fields[], these will be archived in the same
960 // {start_recording_subgraph ... done_recording_subgraph} pass to
961 // save time.
962 for (; i < num; i++) {
963 ArchivableStaticFieldInfo* f = &fields[i];
964 if (f->klass_name != klass_name) {
965 break;
966 }
967 archive_reachable_objects_from_static_field(f->klass, f->klass_name,
968 f->offset, f->field_name,
969 is_closed_archive, CHECK);
970 }
971 done_recording_subgraph(info->klass, klass_name);
972 }
973
974 log_info(cds, heap)("Archived subgraph records in %s archive heap region = %d",
975 is_closed_archive ? "closed" : "open",
976 _num_total_subgraph_recordings);
977 log_info(cds, heap)(" Walked %d objects", _num_total_walked_objs);
978 log_info(cds, heap)(" Archived %d objects", _num_total_archived_objs);
979 log_info(cds, heap)(" Recorded %d klasses", _num_total_recorded_klasses);
980
981 #ifndef PRODUCT
982 for (int i = 0; i < num; i++) {
983 ArchivableStaticFieldInfo* f = &fields[i];
984 verify_subgraph_from_static_field(f->klass, f->offset);
985 }
986 log_info(cds, heap)(" Verified %d references", _num_total_verifications);
987 #endif
988 }
989
990 // At dump-time, find the location of all the non-null oop pointers in an archived heap
991 // region. This way we can quickly relocate all the pointers without using
992 // BasicOopIterateClosure at runtime.
993 class FindEmbeddedNonNullPointers: public BasicOopIterateClosure {
994 narrowOop* _start;
995 BitMap *_oopmap;
996 int _num_total_oops;
997 int _num_null_oops;
998 public:
999 FindEmbeddedNonNullPointers(narrowOop* start, BitMap* oopmap)
1000 : _start(start), _oopmap(oopmap), _num_total_oops(0), _num_null_oops(0) {}
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