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 "gc/shared/gcLocker.hpp"
32 #include "logging/log.hpp"
33 #include "logging/logMessage.hpp"
34 #include "logging/logStream.hpp"
35 #include "memory/archiveUtils.hpp"
36 #include "memory/filemap.hpp"
37 #include "memory/heapShared.inline.hpp"
38 #include "memory/iterator.inline.hpp"
39 #include "memory/metadataFactory.hpp"
40 #include "memory/metaspaceClosure.hpp"
41 #include "memory/metaspaceShared.hpp"
42 #include "memory/resourceArea.hpp"
43 #include "memory/universe.hpp"
44 #include "oops/compressedOops.inline.hpp"
45 #include "oops/fieldStreams.inline.hpp"
46 #include "oops/oop.inline.hpp"
47 #include "runtime/fieldDescriptor.inline.hpp"
48 #include "runtime/safepointVerifiers.hpp"
49 #include "utilities/bitMap.inline.hpp"
50 #if INCLUDE_G1GC
51 #include "gc/g1/g1CollectedHeap.hpp"
52 #endif
53
54 #if INCLUDE_CDS_JAVA_HEAP
55
56 bool HeapShared::_closed_archive_heap_region_mapped = false;
57 bool HeapShared::_open_archive_heap_region_mapped = false;
58 bool HeapShared::_archive_heap_region_fixed = false;
59
60 address HeapShared::_narrow_oop_base;
61 int HeapShared::_narrow_oop_shift;
62
63 //
64 // If you add new entries to the following tables, you should know what you're doing!
65 //
66
67 // Entry fields for shareable subgraphs archived in the closed archive heap
68 // region. Warning: Objects in the subgraphs should not have reference fields
69 // assigned at runtime.
70 static ArchivableStaticFieldInfo closed_archive_subgraph_entry_fields[] = {
71 {"java/lang/Integer$IntegerCache", "archivedCache"},
72 {"java/lang/Long$LongCache", "archivedCache"},
73 {"java/lang/Byte$ByteCache", "archivedCache"},
74 {"java/lang/Short$ShortCache", "archivedCache"},
75 {"java/lang/Character$CharacterCache", "archivedCache"},
76 {"java/util/jar/Attributes$Name", "KNOWN_NAMES"},
77 {"sun/util/locale/BaseLocale", "constantBaseLocales"},
78 };
79 // Entry fields for subgraphs archived in the open archive heap region.
80 static ArchivableStaticFieldInfo open_archive_subgraph_entry_fields[] = {
81 {"jdk/internal/module/ArchivedModuleGraph", "archivedModuleGraph"},
82 {"java/util/ImmutableCollections", "archivedObjects"},
83 {"java/lang/module/Configuration", "EMPTY_CONFIGURATION"},
84 {"jdk/internal/math/FDBigInteger", "archivedCaches"},
85 };
86
87 const static int num_closed_archive_subgraph_entry_fields =
88 sizeof(closed_archive_subgraph_entry_fields) / sizeof(ArchivableStaticFieldInfo);
89 const static int num_open_archive_subgraph_entry_fields =
90 sizeof(open_archive_subgraph_entry_fields) / sizeof(ArchivableStaticFieldInfo);
91
92 ////////////////////////////////////////////////////////////////
93 //
94 // Java heap object archiving support
95 //
96 ////////////////////////////////////////////////////////////////
97 void HeapShared::fixup_mapped_heap_regions() {
98 FileMapInfo *mapinfo = FileMapInfo::current_info();
99 mapinfo->fixup_mapped_heap_regions();
100 set_archive_heap_region_fixed();
101 SystemDictionaryShared::update_archived_mirror_native_pointers();
102 }
103
104 unsigned HeapShared::oop_hash(oop const& p) {
105 assert(!p->mark().has_bias_pattern(),
106 "this object should never have been locked"); // so identity_hash won't safepoin
107 unsigned hash = (unsigned)p->identity_hash();
108 return hash;
109 }
110
111 HeapShared::ArchivedObjectCache* HeapShared::_archived_object_cache = NULL;
112 oop HeapShared::find_archived_heap_object(oop obj) {
113 assert(DumpSharedSpaces, "dump-time only");
114 ArchivedObjectCache* cache = archived_object_cache();
115 oop* p = cache->get(obj);
116 if (p != NULL) {
117 return *p;
118 } else {
119 return NULL;
120 }
121 }
122
123 oop HeapShared::archive_heap_object(oop obj, Thread* THREAD) {
124 assert(DumpSharedSpaces, "dump-time only");
125
126 oop ao = find_archived_heap_object(obj);
127 if (ao != NULL) {
128 // already archived
129 return ao;
130 }
131
132 int len = obj->size();
133 if (G1CollectedHeap::heap()->is_archive_alloc_too_large(len)) {
134 log_debug(cds, heap)("Cannot archive, object (" PTR_FORMAT ") is too large: " SIZE_FORMAT,
135 p2i(obj), (size_t)obj->size());
136 return NULL;
137 }
138
139 oop archived_oop = (oop)G1CollectedHeap::heap()->archive_mem_allocate(len);
140 if (archived_oop != NULL) {
141 Copy::aligned_disjoint_words(cast_from_oop<HeapWord*>(obj), cast_from_oop<HeapWord*>(archived_oop), len);
142 MetaspaceShared::relocate_klass_ptr(archived_oop);
143 // Reinitialize markword to remove age/marking/locking/etc.
144 //
145 // We need to retain the identity_hash, because it may have been used by some hashtables
146 // in the shared heap. This also has the side effect of pre-initializing the
147 // identity_hash for all shared objects, so they are less likely to be written
148 // into during run time, increasing the potential of memory sharing.
149 int hash_original = obj->identity_hash();
150 archived_oop->set_mark_raw(markWord::prototype().copy_set_hash(hash_original));
151 assert(archived_oop->mark().is_unlocked(), "sanity");
152
153 DEBUG_ONLY(int hash_archived = archived_oop->identity_hash());
154 assert(hash_original == hash_archived, "Different hash codes: original %x, archived %x", hash_original, hash_archived);
155
156 ArchivedObjectCache* cache = archived_object_cache();
157 cache->put(obj, archived_oop);
158 log_debug(cds, heap)("Archived heap object " PTR_FORMAT " ==> " PTR_FORMAT,
159 p2i(obj), p2i(archived_oop));
160 } else {
161 log_error(cds, heap)(
162 "Cannot allocate space for object " PTR_FORMAT " in archived heap region",
163 p2i(obj));
164 vm_exit(1);
165 }
166 return archived_oop;
167 }
168
169 oop HeapShared::materialize_archived_object(narrowOop v) {
170 assert(archive_heap_region_fixed(),
171 "must be called after archive heap regions are fixed");
172 if (!CompressedOops::is_null(v)) {
173 oop obj = HeapShared::decode_from_archive(v);
174 return G1CollectedHeap::heap()->materialize_archived_object(obj);
175 }
176 return NULL;
177 }
178
179 void HeapShared::archive_klass_objects(Thread* THREAD) {
180 GrowableArray<Klass*>* klasses = MetaspaceShared::collected_klasses();
181 assert(klasses != NULL, "sanity");
182 for (int i = 0; i < klasses->length(); i++) {
183 Klass* k = klasses->at(i);
184
185 // archive mirror object
186 java_lang_Class::archive_mirror(k, CHECK);
187
188 // archive the resolved_referenes array
189 if (k->is_instance_klass()) {
190 InstanceKlass* ik = InstanceKlass::cast(k);
191 ik->constants()->archive_resolved_references(THREAD);
192 }
193 }
194 }
195
196 void HeapShared::run_full_gc_in_vm_thread() {
197 if (is_heap_object_archiving_allowed()) {
198 // Avoid fragmentation while archiving heap objects.
199 // We do this inside a safepoint, so that no further allocation can happen after GC
200 // has finished.
201 if (GCLocker::is_active()) {
202 // Just checking for safety ...
203 // This should not happen during -Xshare:dump. If you see this, probably the Java core lib
204 // has been modified such that JNI code is executed in some clean up threads after
205 // we have finished class loading.
206 log_warning(cds)("GC locker is held, unable to start extra compacting GC. This may produce suboptimal results.");
207 } else {
208 log_info(cds)("Run GC ...");
209 Universe::heap()->collect_as_vm_thread(GCCause::_archive_time_gc);
210 log_info(cds)("Run GC done");
211 }
212 }
213 }
214
215 void HeapShared::archive_java_heap_objects(GrowableArray<MemRegion> *closed,
216 GrowableArray<MemRegion> *open) {
217 if (!is_heap_object_archiving_allowed()) {
218 log_info(cds)(
219 "Archived java heap is not supported as UseG1GC, "
220 "UseCompressedOops and UseCompressedClassPointers are required."
221 "Current settings: UseG1GC=%s, UseCompressedOops=%s, UseCompressedClassPointers=%s.",
222 BOOL_TO_STR(UseG1GC), BOOL_TO_STR(UseCompressedOops),
223 BOOL_TO_STR(UseCompressedClassPointers));
224 return;
225 }
226
227 G1HeapVerifier::verify_ready_for_archiving();
228
229 {
230 NoSafepointVerifier nsv;
231
232 // Cache for recording where the archived objects are copied to
233 create_archived_object_cache();
234
235 log_info(cds)("Dumping objects to closed archive heap region ...");
236 NOT_PRODUCT(StringTable::verify());
237 copy_closed_archive_heap_objects(closed);
238
239 log_info(cds)("Dumping objects to open archive heap region ...");
240 copy_open_archive_heap_objects(open);
241
242 destroy_archived_object_cache();
243 }
244
245 G1HeapVerifier::verify_archive_regions();
246 }
247
248 void HeapShared::copy_closed_archive_heap_objects(
249 GrowableArray<MemRegion> * closed_archive) {
250 assert(is_heap_object_archiving_allowed(), "Cannot archive java heap objects");
251
252 Thread* THREAD = Thread::current();
253 G1CollectedHeap::heap()->begin_archive_alloc_range();
254
255 // Archive interned string objects
256 StringTable::write_to_archive();
257
258 archive_object_subgraphs(closed_archive_subgraph_entry_fields,
259 num_closed_archive_subgraph_entry_fields,
260 true /* is_closed_archive */, THREAD);
261
262 G1CollectedHeap::heap()->end_archive_alloc_range(closed_archive,
263 os::vm_allocation_granularity());
264 }
265
266 void HeapShared::copy_open_archive_heap_objects(
267 GrowableArray<MemRegion> * open_archive) {
268 assert(is_heap_object_archiving_allowed(), "Cannot archive java heap objects");
269
270 Thread* THREAD = Thread::current();
271 G1CollectedHeap::heap()->begin_archive_alloc_range(true /* open */);
272
273 java_lang_Class::archive_basic_type_mirrors(THREAD);
274
275 archive_klass_objects(THREAD);
276
277 archive_object_subgraphs(open_archive_subgraph_entry_fields,
278 num_open_archive_subgraph_entry_fields,
279 false /* is_closed_archive */,
280 THREAD);
281
282 G1CollectedHeap::heap()->end_archive_alloc_range(open_archive,
283 os::vm_allocation_granularity());
284 }
285
286 void HeapShared::init_narrow_oop_decoding(address base, int shift) {
287 _narrow_oop_base = base;
288 _narrow_oop_shift = shift;
289 }
290
291 //
292 // Subgraph archiving support
293 //
294 HeapShared::DumpTimeKlassSubGraphInfoTable* HeapShared::_dump_time_subgraph_info_table = NULL;
295 HeapShared::RunTimeKlassSubGraphInfoTable HeapShared::_run_time_subgraph_info_table;
296
297 // Get the subgraph_info for Klass k. A new subgraph_info is created if
298 // there is no existing one for k. The subgraph_info records the relocated
299 // Klass* of the original k.
300 KlassSubGraphInfo* HeapShared::get_subgraph_info(Klass* k) {
301 assert(DumpSharedSpaces, "dump time only");
302 Klass* relocated_k = MetaspaceShared::get_relocated_klass(k);
303 KlassSubGraphInfo* info = _dump_time_subgraph_info_table->get(relocated_k);
304 if (info == NULL) {
305 _dump_time_subgraph_info_table->put(relocated_k, KlassSubGraphInfo(relocated_k));
306 info = _dump_time_subgraph_info_table->get(relocated_k);
307 ++ _dump_time_subgraph_info_table->_count;
308 }
309 return info;
310 }
311
312 // Add an entry field to the current KlassSubGraphInfo.
313 void KlassSubGraphInfo::add_subgraph_entry_field(
314 int static_field_offset, oop v, bool is_closed_archive) {
315 assert(DumpSharedSpaces, "dump time only");
316 if (_subgraph_entry_fields == NULL) {
317 _subgraph_entry_fields =
318 new(ResourceObj::C_HEAP, mtClass) GrowableArray<juint>(10, mtClass);
319 }
320 _subgraph_entry_fields->append((juint)static_field_offset);
321 _subgraph_entry_fields->append(CompressedOops::encode(v));
322 _subgraph_entry_fields->append(is_closed_archive ? 1 : 0);
323 }
324
325 // Add the Klass* for an object in the current KlassSubGraphInfo's subgraphs.
326 // Only objects of boot classes can be included in sub-graph.
327 void KlassSubGraphInfo::add_subgraph_object_klass(Klass* orig_k, Klass *relocated_k) {
328 assert(DumpSharedSpaces, "dump time only");
329 assert(relocated_k == MetaspaceShared::get_relocated_klass(orig_k),
330 "must be the relocated Klass in the shared space");
331
332 if (_subgraph_object_klasses == NULL) {
333 _subgraph_object_klasses =
334 new(ResourceObj::C_HEAP, mtClass) GrowableArray<Klass*>(50, mtClass);
335 }
336
337 assert(relocated_k->is_shared(), "must be a shared class");
338
339 if (_k == relocated_k) {
340 // Don't add the Klass containing the sub-graph to it's own klass
341 // initialization list.
342 return;
343 }
344
345 if (relocated_k->is_instance_klass()) {
346 assert(InstanceKlass::cast(relocated_k)->is_shared_boot_class(),
347 "must be boot class");
348 // SystemDictionary::xxx_klass() are not updated, need to check
349 // the original Klass*
350 if (orig_k == SystemDictionary::String_klass() ||
351 orig_k == SystemDictionary::Object_klass()) {
352 // Initialized early during VM initialization. No need to be added
353 // to the sub-graph object class list.
354 return;
355 }
356 } else if (relocated_k->is_objArray_klass()) {
357 Klass* abk = ObjArrayKlass::cast(relocated_k)->bottom_klass();
358 if (abk->is_instance_klass()) {
359 assert(InstanceKlass::cast(abk)->is_shared_boot_class(),
360 "must be boot class");
361 }
362 if (relocated_k == Universe::objectArrayKlassObj()) {
363 // Initialized early during Universe::genesis. No need to be added
364 // to the list.
365 return;
366 }
367 } else {
368 assert(relocated_k->is_typeArray_klass(), "must be");
369 // Primitive type arrays are created early during Universe::genesis.
370 return;
371 }
372
373 if (log_is_enabled(Debug, cds, heap)) {
374 if (!_subgraph_object_klasses->contains(relocated_k)) {
375 ResourceMark rm;
376 log_debug(cds, heap)("Adding klass %s", orig_k->external_name());
377 }
378 }
379
380 _subgraph_object_klasses->append_if_missing(relocated_k);
381 }
382
383 // Initialize an archived subgraph_info_record from the given KlassSubGraphInfo.
384 void ArchivedKlassSubGraphInfoRecord::init(KlassSubGraphInfo* info) {
385 _k = info->klass();
386 _entry_field_records = NULL;
387 _subgraph_object_klasses = NULL;
388
389 // populate the entry fields
390 GrowableArray<juint>* entry_fields = info->subgraph_entry_fields();
391 if (entry_fields != NULL) {
392 int num_entry_fields = entry_fields->length();
393 assert(num_entry_fields % 3 == 0, "sanity");
394 _entry_field_records =
395 MetaspaceShared::new_ro_array<juint>(num_entry_fields);
396 for (int i = 0 ; i < num_entry_fields; i++) {
397 _entry_field_records->at_put(i, entry_fields->at(i));
398 }
399 }
400
401 // the Klasses of the objects in the sub-graphs
402 GrowableArray<Klass*>* subgraph_object_klasses = info->subgraph_object_klasses();
403 if (subgraph_object_klasses != NULL) {
404 int num_subgraphs_klasses = subgraph_object_klasses->length();
405 _subgraph_object_klasses =
406 MetaspaceShared::new_ro_array<Klass*>(num_subgraphs_klasses);
407 for (int i = 0; i < num_subgraphs_klasses; i++) {
408 Klass* subgraph_k = subgraph_object_klasses->at(i);
409 if (log_is_enabled(Info, cds, heap)) {
410 ResourceMark rm;
411 log_info(cds, heap)(
412 "Archived object klass %s (%2d) => %s",
413 _k->external_name(), i, subgraph_k->external_name());
414 }
415 _subgraph_object_klasses->at_put(i, subgraph_k);
416 ArchivePtrMarker::mark_pointer(_subgraph_object_klasses->adr_at(i));
417 }
418 }
419
420 ArchivePtrMarker::mark_pointer(&_k);
421 ArchivePtrMarker::mark_pointer(&_entry_field_records);
422 ArchivePtrMarker::mark_pointer(&_subgraph_object_klasses);
423 }
424
425 struct CopyKlassSubGraphInfoToArchive : StackObj {
426 CompactHashtableWriter* _writer;
427 CopyKlassSubGraphInfoToArchive(CompactHashtableWriter* writer) : _writer(writer) {}
428
429 bool do_entry(Klass* klass, KlassSubGraphInfo& info) {
430 if (info.subgraph_object_klasses() != NULL || info.subgraph_entry_fields() != NULL) {
431 ArchivedKlassSubGraphInfoRecord* record =
432 (ArchivedKlassSubGraphInfoRecord*)MetaspaceShared::read_only_space_alloc(sizeof(ArchivedKlassSubGraphInfoRecord));
433 record->init(&info);
434
435 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary(klass);
436 u4 delta = MetaspaceShared::object_delta_u4(record);
437 _writer->add(hash, delta);
438 }
439 return true; // keep on iterating
440 }
441 };
442
443 // Build the records of archived subgraph infos, which include:
444 // - Entry points to all subgraphs from the containing class mirror. The entry
445 // points are static fields in the mirror. For each entry point, the field
446 // offset, value and is_closed_archive flag are recorded in the sub-graph
447 // info. The value is stored back to the corresponding field at runtime.
448 // - A list of klasses that need to be loaded/initialized before archived
449 // java object sub-graph can be accessed at runtime.
450 void HeapShared::write_subgraph_info_table() {
451 // Allocate the contents of the hashtable(s) inside the RO region of the CDS archive.
452 DumpTimeKlassSubGraphInfoTable* d_table = _dump_time_subgraph_info_table;
453 CompactHashtableStats stats;
454
455 _run_time_subgraph_info_table.reset();
456
457 CompactHashtableWriter writer(d_table->_count, &stats);
458 CopyKlassSubGraphInfoToArchive copy(&writer);
459 d_table->iterate(©);
460
461 writer.dump(&_run_time_subgraph_info_table, "subgraphs");
462 }
463
464 void HeapShared::serialize_subgraph_info_table_header(SerializeClosure* soc) {
465 _run_time_subgraph_info_table.serialize_header(soc);
466 }
467
468 void HeapShared::initialize_from_archived_subgraph(Klass* k) {
469 if (!open_archive_heap_region_mapped()) {
470 return; // nothing to do
471 }
472 assert(!DumpSharedSpaces, "Should not be called with DumpSharedSpaces");
473
474 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary(k);
475 const ArchivedKlassSubGraphInfoRecord* record = _run_time_subgraph_info_table.lookup(k, hash, 0);
476
477 // Initialize from archived data. Currently this is done only
478 // during VM initialization time. No lock is needed.
479 if (record != NULL) {
480 Thread* THREAD = Thread::current();
481
482 int i;
483 // Load/link/initialize the klasses of the objects in the subgraph.
484 // NULL class loader is used.
485 Array<Klass*>* klasses = record->subgraph_object_klasses();
486 if (klasses != NULL) {
487 for (i = 0; i < klasses->length(); i++) {
488 Klass* obj_k = klasses->at(i);
489 Klass* resolved_k = SystemDictionary::resolve_or_null(
490 (obj_k)->name(), THREAD);
491 if (resolved_k != obj_k) {
492 assert(!SystemDictionary::is_well_known_klass(resolved_k),
493 "shared well-known classes must not be replaced by JVMTI ClassFileLoadHook");
494 ResourceMark rm(THREAD);
495 log_info(cds, heap)("Failed to load subgraph because %s was not loaded from archive",
496 resolved_k->external_name());
497 return;
498 }
499 if ((obj_k)->is_instance_klass()) {
500 InstanceKlass* ik = InstanceKlass::cast(obj_k);
501 ik->initialize(THREAD);
502 } else if ((obj_k)->is_objArray_klass()) {
503 ObjArrayKlass* oak = ObjArrayKlass::cast(obj_k);
504 oak->initialize(THREAD);
505 }
506 }
507 }
508
509 if (HAS_PENDING_EXCEPTION) {
510 CLEAR_PENDING_EXCEPTION;
511 // None of the field value will be set if there was an exception.
512 // The java code will not see any of the archived objects in the
513 // subgraphs referenced from k in this case.
514 return;
515 }
516
517 // Load the subgraph entry fields from the record and store them back to
518 // the corresponding fields within the mirror.
519 oop m = k->java_mirror();
520 Array<juint>* entry_field_records = record->entry_field_records();
521 if (entry_field_records != NULL) {
522 int efr_len = entry_field_records->length();
523 assert(efr_len % 3 == 0, "sanity");
524 for (i = 0; i < efr_len;) {
525 int field_offset = entry_field_records->at(i);
526 narrowOop nv = entry_field_records->at(i+1);
527 int is_closed_archive = entry_field_records->at(i+2);
528 oop v;
529 if (is_closed_archive == 0) {
530 // It's an archived object in the open archive heap regions, not shared.
531 // The object refereced by the field becomes 'known' by GC from this
532 // point. All objects in the subgraph reachable from the object are
533 // also 'known' by GC.
534 v = materialize_archived_object(nv);
535 } else {
536 // Shared object in the closed archive heap regions. Decode directly.
537 assert(!CompressedOops::is_null(nv), "shared object is null");
538 v = HeapShared::decode_from_archive(nv);
539 }
540 m->obj_field_put(field_offset, v);
541 i += 3;
542
543 log_debug(cds, heap)(" " PTR_FORMAT " init field @ %2d = " PTR_FORMAT, p2i(k), field_offset, p2i(v));
544 }
545
546 // Done. Java code can see the archived sub-graphs referenced from k's
547 // mirror after this point.
548 if (log_is_enabled(Info, cds, heap)) {
549 ResourceMark rm;
550 log_info(cds, heap)("initialize_from_archived_subgraph %s " PTR_FORMAT,
551 k->external_name(), p2i(k));
552 }
553 }
554 }
555 }
556
557 class WalkOopAndArchiveClosure: public BasicOopIterateClosure {
558 int _level;
559 bool _is_closed_archive;
560 bool _record_klasses_only;
561 KlassSubGraphInfo* _subgraph_info;
562 oop _orig_referencing_obj;
563 oop _archived_referencing_obj;
564 Thread* _thread;
565 public:
566 WalkOopAndArchiveClosure(int level,
567 bool is_closed_archive,
568 bool record_klasses_only,
569 KlassSubGraphInfo* subgraph_info,
570 oop orig, oop archived, TRAPS) :
571 _level(level), _is_closed_archive(is_closed_archive),
572 _record_klasses_only(record_klasses_only),
573 _subgraph_info(subgraph_info),
574 _orig_referencing_obj(orig), _archived_referencing_obj(archived),
575 _thread(THREAD) {}
576 void do_oop(narrowOop *p) { WalkOopAndArchiveClosure::do_oop_work(p); }
577 void do_oop( oop *p) { WalkOopAndArchiveClosure::do_oop_work(p); }
578
579 protected:
580 template <class T> void do_oop_work(T *p) {
581 oop obj = RawAccess<>::oop_load(p);
582 if (!CompressedOops::is_null(obj)) {
583 assert(!HeapShared::is_archived_object(obj),
584 "original objects must not point to archived objects");
585
586 size_t field_delta = pointer_delta(p, _orig_referencing_obj, sizeof(char));
587 T* new_p = (T*)(cast_from_oop<address>(_archived_referencing_obj) + field_delta);
588 Thread* THREAD = _thread;
589
590 if (!_record_klasses_only && log_is_enabled(Debug, cds, heap)) {
591 ResourceMark rm;
592 log_debug(cds, heap)("(%d) %s[" SIZE_FORMAT "] ==> " PTR_FORMAT " size %d %s", _level,
593 _orig_referencing_obj->klass()->external_name(), field_delta,
594 p2i(obj), obj->size() * HeapWordSize, obj->klass()->external_name());
595 LogTarget(Trace, cds, heap) log;
596 LogStream out(log);
597 obj->print_on(&out);
598 }
599
600 oop archived = HeapShared::archive_reachable_objects_from(
601 _level + 1, _subgraph_info, obj, _is_closed_archive, THREAD);
602 assert(archived != NULL, "VM should have exited with unarchivable objects for _level > 1");
603 assert(HeapShared::is_archived_object(archived), "must be");
604
605 if (!_record_klasses_only) {
606 // Update the reference in the archived copy of the referencing object.
607 log_debug(cds, heap)("(%d) updating oop @[" PTR_FORMAT "] " PTR_FORMAT " ==> " PTR_FORMAT,
608 _level, p2i(new_p), p2i(obj), p2i(archived));
609 RawAccess<IS_NOT_NULL>::oop_store(new_p, archived);
610 }
611 }
612 }
613 };
614
615 void HeapShared::check_closed_archive_heap_region_object(InstanceKlass* k,
616 Thread* THREAD) {
617 // Check fields in the object
618 for (JavaFieldStream fs(k); !fs.done(); fs.next()) {
619 if (!fs.access_flags().is_static()) {
620 BasicType ft = fs.field_descriptor().field_type();
621 if (!fs.access_flags().is_final() && is_reference_type(ft)) {
622 ResourceMark rm(THREAD);
623 log_warning(cds, heap)(
624 "Please check reference field in %s instance in closed archive heap region: %s %s",
625 k->external_name(), (fs.name())->as_C_string(),
626 (fs.signature())->as_C_string());
627 }
628 }
629 }
630 }
631
632 // (1) If orig_obj has not been archived yet, archive it.
633 // (2) If orig_obj has not been seen yet (since start_recording_subgraph() was called),
634 // trace all objects that are reachable from it, and make sure these objects are archived.
635 // (3) Record the klasses of all orig_obj and all reachable objects.
636 oop HeapShared::archive_reachable_objects_from(int level,
637 KlassSubGraphInfo* subgraph_info,
638 oop orig_obj,
639 bool is_closed_archive,
640 TRAPS) {
641 assert(orig_obj != NULL, "must be");
642 assert(!is_archived_object(orig_obj), "sanity");
643
644 if (!JavaClasses::is_supported_for_archiving(orig_obj)) {
645 // This object has injected fields that cannot be supported easily, so we disallow them for now.
646 // If you get an error here, you probably made a change in the JDK library that has added
647 // these objects that are referenced (directly or indirectly) by static fields.
648 ResourceMark rm;
649 log_error(cds, heap)("Cannot archive object of class %s", orig_obj->klass()->external_name());
650 vm_exit(1);
651 }
652
653 // java.lang.Class instances cannot be included in an archived object sub-graph. We only support
654 // them as Klass::_archived_mirror because they need to be specially restored at run time.
655 //
656 // If you get an error here, you probably made a change in the JDK library that has added a Class
657 // object that is referenced (directly or indirectly) by static fields.
658 if (java_lang_Class::is_instance(orig_obj)) {
659 log_error(cds, heap)("(%d) Unknown java.lang.Class object is in the archived sub-graph", level);
660 vm_exit(1);
661 }
662
663 oop archived_obj = find_archived_heap_object(orig_obj);
664 if (java_lang_String::is_instance(orig_obj) && archived_obj != NULL) {
665 // To save time, don't walk strings that are already archived. They just contain
666 // pointers to a type array, whose klass doesn't need to be recorded.
667 return archived_obj;
668 }
669
670 if (has_been_seen_during_subgraph_recording(orig_obj)) {
671 // orig_obj has already been archived and traced. Nothing more to do.
672 return archived_obj;
673 } else {
674 set_has_been_seen_during_subgraph_recording(orig_obj);
675 }
676
677 bool record_klasses_only = (archived_obj != NULL);
678 if (archived_obj == NULL) {
679 ++_num_new_archived_objs;
680 archived_obj = archive_heap_object(orig_obj, THREAD);
681 if (archived_obj == NULL) {
682 // Skip archiving the sub-graph referenced from the current entry field.
683 ResourceMark rm;
684 log_error(cds, heap)(
685 "Cannot archive the sub-graph referenced from %s object ("
686 PTR_FORMAT ") size %d, skipped.",
687 orig_obj->klass()->external_name(), p2i(orig_obj), orig_obj->size() * HeapWordSize);
688 if (level == 1) {
689 // Don't archive a subgraph root that's too big. For archives static fields, that's OK
690 // as the Java code will take care of initializing this field dynamically.
691 return NULL;
692 } else {
693 // We don't know how to handle an object that has been archived, but some of its reachable
694 // objects cannot be archived. Bail out for now. We might need to fix this in the future if
695 // we have a real use case.
696 vm_exit(1);
697 }
698 }
699 }
700
701 assert(archived_obj != NULL, "must be");
702 Klass *orig_k = orig_obj->klass();
703 Klass *relocated_k = archived_obj->klass();
704 subgraph_info->add_subgraph_object_klass(orig_k, relocated_k);
705
706 WalkOopAndArchiveClosure walker(level, is_closed_archive, record_klasses_only,
707 subgraph_info, orig_obj, archived_obj, THREAD);
708 orig_obj->oop_iterate(&walker);
709 if (is_closed_archive && orig_k->is_instance_klass()) {
710 check_closed_archive_heap_region_object(InstanceKlass::cast(orig_k), THREAD);
711 }
712 return archived_obj;
713 }
714
715 //
716 // Start from the given static field in a java mirror and archive the
717 // complete sub-graph of java heap objects that are reached directly
718 // or indirectly from the starting object by following references.
719 // Sub-graph archiving restrictions (current):
720 //
721 // - All classes of objects in the archived sub-graph (including the
722 // entry class) must be boot class only.
723 // - No java.lang.Class instance (java mirror) can be included inside
724 // an archived sub-graph. Mirror can only be the sub-graph entry object.
725 //
726 // The Java heap object sub-graph archiving process (see
727 // WalkOopAndArchiveClosure):
728 //
729 // 1) Java object sub-graph archiving starts from a given static field
730 // within a Class instance (java mirror). If the static field is a
731 // refererence field and points to a non-null java object, proceed to
732 // the next step.
733 //
734 // 2) Archives the referenced java object. If an archived copy of the
735 // current object already exists, updates the pointer in the archived
736 // copy of the referencing object to point to the current archived object.
737 // Otherwise, proceed to the next step.
738 //
739 // 3) Follows all references within the current java object and recursively
740 // archive the sub-graph of objects starting from each reference.
741 //
742 // 4) Updates the pointer in the archived copy of referencing object to
743 // point to the current archived object.
744 //
745 // 5) The Klass of the current java object is added to the list of Klasses
746 // for loading and initialzing before any object in the archived graph can
747 // be accessed at runtime.
748 //
749 void HeapShared::archive_reachable_objects_from_static_field(InstanceKlass *k,
750 const char* klass_name,
751 int field_offset,
752 const char* field_name,
753 bool is_closed_archive,
754 TRAPS) {
755 assert(DumpSharedSpaces, "dump time only");
756 assert(k->is_shared_boot_class(), "must be boot class");
757
758 oop m = k->java_mirror();
759
760 KlassSubGraphInfo* subgraph_info = get_subgraph_info(k);
761 oop f = m->obj_field(field_offset);
762
763 log_debug(cds, heap)("Start archiving from: %s::%s (" PTR_FORMAT ")", klass_name, field_name, p2i(f));
764
765 if (!CompressedOops::is_null(f)) {
766 if (log_is_enabled(Trace, cds, heap)) {
767 LogTarget(Trace, cds, heap) log;
768 LogStream out(log);
769 f->print_on(&out);
770 }
771
772 oop af = archive_reachable_objects_from(1, subgraph_info, f,
773 is_closed_archive, CHECK);
774
775 if (af == NULL) {
776 log_error(cds, heap)("Archiving failed %s::%s (some reachable objects cannot be archived)",
777 klass_name, field_name);
778 } else {
779 // Note: the field value is not preserved in the archived mirror.
780 // Record the field as a new subGraph entry point. The recorded
781 // information is restored from the archive at runtime.
782 subgraph_info->add_subgraph_entry_field(field_offset, af, is_closed_archive);
783 log_info(cds, heap)("Archived field %s::%s => " PTR_FORMAT, klass_name, field_name, p2i(af));
784 }
785 } else {
786 // The field contains null, we still need to record the entry point,
787 // so it can be restored at runtime.
788 subgraph_info->add_subgraph_entry_field(field_offset, NULL, false);
789 }
790 }
791
792 #ifndef PRODUCT
793 class VerifySharedOopClosure: public BasicOopIterateClosure {
794 private:
795 bool _is_archived;
796
797 public:
798 VerifySharedOopClosure(bool is_archived) : _is_archived(is_archived) {}
799
800 void do_oop(narrowOop *p) { VerifySharedOopClosure::do_oop_work(p); }
801 void do_oop( oop *p) { VerifySharedOopClosure::do_oop_work(p); }
802
803 protected:
804 template <class T> void do_oop_work(T *p) {
805 oop obj = RawAccess<>::oop_load(p);
806 if (!CompressedOops::is_null(obj)) {
807 HeapShared::verify_reachable_objects_from(obj, _is_archived);
808 }
809 }
810 };
811
812 void HeapShared::verify_subgraph_from_static_field(InstanceKlass* k, int field_offset) {
813 assert(DumpSharedSpaces, "dump time only");
814 assert(k->is_shared_boot_class(), "must be boot class");
815
816 oop m = k->java_mirror();
817 oop f = m->obj_field(field_offset);
818 if (!CompressedOops::is_null(f)) {
819 verify_subgraph_from(f);
820 }
821 }
822
823 void HeapShared::verify_subgraph_from(oop orig_obj) {
824 oop archived_obj = find_archived_heap_object(orig_obj);
825 if (archived_obj == NULL) {
826 // It's OK for the root of a subgraph to be not archived. See comments in
827 // archive_reachable_objects_from().
828 return;
829 }
830
831 // Verify that all objects reachable from orig_obj are archived.
832 init_seen_objects_table();
833 verify_reachable_objects_from(orig_obj, false);
834 delete_seen_objects_table();
835
836 // Note: we could also verify that all objects reachable from the archived
837 // copy of orig_obj can only point to archived objects, with:
838 // init_seen_objects_table();
839 // verify_reachable_objects_from(archived_obj, true);
840 // init_seen_objects_table();
841 // but that's already done in G1HeapVerifier::verify_archive_regions so we
842 // won't do it here.
843 }
844
845 void HeapShared::verify_reachable_objects_from(oop obj, bool is_archived) {
846 _num_total_verifications ++;
847 if (!has_been_seen_during_subgraph_recording(obj)) {
848 set_has_been_seen_during_subgraph_recording(obj);
849
850 if (is_archived) {
851 assert(is_archived_object(obj), "must be");
852 assert(find_archived_heap_object(obj) == NULL, "must be");
853 } else {
854 assert(!is_archived_object(obj), "must be");
855 assert(find_archived_heap_object(obj) != NULL, "must be");
856 }
857
858 VerifySharedOopClosure walker(is_archived);
859 obj->oop_iterate(&walker);
860 }
861 }
862 #endif
863
864 HeapShared::SeenObjectsTable* HeapShared::_seen_objects_table = NULL;
865 int HeapShared::_num_new_walked_objs;
866 int HeapShared::_num_new_archived_objs;
867 int HeapShared::_num_old_recorded_klasses;
868
869 int HeapShared::_num_total_subgraph_recordings = 0;
870 int HeapShared::_num_total_walked_objs = 0;
871 int HeapShared::_num_total_archived_objs = 0;
872 int HeapShared::_num_total_recorded_klasses = 0;
873 int HeapShared::_num_total_verifications = 0;
874
875 bool HeapShared::has_been_seen_during_subgraph_recording(oop obj) {
876 return _seen_objects_table->get(obj) != NULL;
877 }
878
879 void HeapShared::set_has_been_seen_during_subgraph_recording(oop obj) {
880 assert(!has_been_seen_during_subgraph_recording(obj), "sanity");
881 _seen_objects_table->put(obj, true);
882 ++ _num_new_walked_objs;
883 }
884
885 void HeapShared::start_recording_subgraph(InstanceKlass *k, const char* class_name) {
886 log_info(cds, heap)("Start recording subgraph(s) for archived fields in %s", class_name);
887 init_seen_objects_table();
888 _num_new_walked_objs = 0;
889 _num_new_archived_objs = 0;
890 _num_old_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses();
891 }
892
893 void HeapShared::done_recording_subgraph(InstanceKlass *k, const char* class_name) {
894 int num_new_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses() -
895 _num_old_recorded_klasses;
896 log_info(cds, heap)("Done recording subgraph(s) for archived fields in %s: "
897 "walked %d objs, archived %d new objs, recorded %d classes",
898 class_name, _num_new_walked_objs, _num_new_archived_objs,
899 num_new_recorded_klasses);
900
901 delete_seen_objects_table();
902
903 _num_total_subgraph_recordings ++;
904 _num_total_walked_objs += _num_new_walked_objs;
905 _num_total_archived_objs += _num_new_archived_objs;
906 _num_total_recorded_klasses += num_new_recorded_klasses;
907 }
908
909 class ArchivableStaticFieldFinder: public FieldClosure {
910 InstanceKlass* _ik;
911 Symbol* _field_name;
912 bool _found;
913 int _offset;
914 public:
915 ArchivableStaticFieldFinder(InstanceKlass* ik, Symbol* field_name) :
916 _ik(ik), _field_name(field_name), _found(false), _offset(-1) {}
917
918 virtual void do_field(fieldDescriptor* fd) {
919 if (fd->name() == _field_name) {
920 assert(!_found, "fields cannot be overloaded");
921 assert(is_reference_type(fd->field_type()), "can archive only fields that are references");
922 _found = true;
923 _offset = fd->offset();
924 }
925 }
926 bool found() { return _found; }
927 int offset() { return _offset; }
928 };
929
930 void HeapShared::init_subgraph_entry_fields(ArchivableStaticFieldInfo fields[],
931 int num, Thread* THREAD) {
932 for (int i = 0; i < num; i++) {
933 ArchivableStaticFieldInfo* info = &fields[i];
934 TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name);
935 TempNewSymbol field_name = SymbolTable::new_symbol(info->field_name);
936
937 Klass* k = SystemDictionary::resolve_or_null(klass_name, THREAD);
938 assert(k != NULL && !HAS_PENDING_EXCEPTION, "class must exist");
939 InstanceKlass* ik = InstanceKlass::cast(k);
940 assert(InstanceKlass::cast(ik)->is_shared_boot_class(),
941 "Only support boot classes");
942 ik->initialize(THREAD);
943 guarantee(!HAS_PENDING_EXCEPTION, "exception in initialize");
944
945 ArchivableStaticFieldFinder finder(ik, field_name);
946 ik->do_local_static_fields(&finder);
947 assert(finder.found(), "field must exist");
948
949 info->klass = ik;
950 info->offset = finder.offset();
951 }
952 }
953
954 void HeapShared::init_subgraph_entry_fields(Thread* THREAD) {
955 _dump_time_subgraph_info_table = new (ResourceObj::C_HEAP, mtClass)DumpTimeKlassSubGraphInfoTable();
956
957 init_subgraph_entry_fields(closed_archive_subgraph_entry_fields,
958 num_closed_archive_subgraph_entry_fields,
959 THREAD);
960 init_subgraph_entry_fields(open_archive_subgraph_entry_fields,
961 num_open_archive_subgraph_entry_fields,
962 THREAD);
963 }
964
965 void HeapShared::archive_object_subgraphs(ArchivableStaticFieldInfo fields[],
966 int num, bool is_closed_archive,
967 Thread* THREAD) {
968 _num_total_subgraph_recordings = 0;
969 _num_total_walked_objs = 0;
970 _num_total_archived_objs = 0;
971 _num_total_recorded_klasses = 0;
972 _num_total_verifications = 0;
973
974 // For each class X that has one or more archived fields:
975 // [1] Dump the subgraph of each archived field
976 // [2] Create a list of all the class of the objects that can be reached
977 // by any of these static fields.
978 // At runtime, these classes are initialized before X's archived fields
979 // are restored by HeapShared::initialize_from_archived_subgraph().
980 int i;
981 for (i = 0; i < num; ) {
982 ArchivableStaticFieldInfo* info = &fields[i];
983 const char* klass_name = info->klass_name;
984 start_recording_subgraph(info->klass, klass_name);
985
986 // If you have specified consecutive fields of the same klass in
987 // fields[], these will be archived in the same
988 // {start_recording_subgraph ... done_recording_subgraph} pass to
989 // save time.
990 for (; i < num; i++) {
991 ArchivableStaticFieldInfo* f = &fields[i];
992 if (f->klass_name != klass_name) {
993 break;
994 }
995 archive_reachable_objects_from_static_field(f->klass, f->klass_name,
996 f->offset, f->field_name,
997 is_closed_archive, CHECK);
998 }
999 done_recording_subgraph(info->klass, klass_name);
1000 }
1001
1002 log_info(cds, heap)("Archived subgraph records in %s archive heap region = %d",
1003 is_closed_archive ? "closed" : "open",
1004 _num_total_subgraph_recordings);
1005 log_info(cds, heap)(" Walked %d objects", _num_total_walked_objs);
1006 log_info(cds, heap)(" Archived %d objects", _num_total_archived_objs);
1007 log_info(cds, heap)(" Recorded %d klasses", _num_total_recorded_klasses);
1008
1009 #ifndef PRODUCT
1010 for (int i = 0; i < num; i++) {
1011 ArchivableStaticFieldInfo* f = &fields[i];
1012 verify_subgraph_from_static_field(f->klass, f->offset);
1013 }
1014 log_info(cds, heap)(" Verified %d references", _num_total_verifications);
1015 #endif
1016 }
1017
1018 // At dump-time, find the location of all the non-null oop pointers in an archived heap
1019 // region. This way we can quickly relocate all the pointers without using
1020 // BasicOopIterateClosure at runtime.
1021 class FindEmbeddedNonNullPointers: public BasicOopIterateClosure {
1022 narrowOop* _start;
1023 BitMap *_oopmap;
1024 int _num_total_oops;
1025 int _num_null_oops;
1026 public:
1027 FindEmbeddedNonNullPointers(narrowOop* start, BitMap* oopmap)
1028 : _start(start), _oopmap(oopmap), _num_total_oops(0), _num_null_oops(0) {}
1029
1030 virtual bool should_verify_oops(void) {
1031 return false;
1032 }
1033 virtual void do_oop(narrowOop* p) {
1034 _num_total_oops ++;
1035 narrowOop v = *p;
1036 if (!CompressedOops::is_null(v)) {
1037 size_t idx = p - _start;
1038 _oopmap->set_bit(idx);
1039 } else {
1040 _num_null_oops ++;
1041 }
1042 }
1043 virtual void do_oop(oop *p) {
1044 ShouldNotReachHere();
1045 }
1046 int num_total_oops() const { return _num_total_oops; }
1047 int num_null_oops() const { return _num_null_oops; }
1048 };
1049
1050 ResourceBitMap HeapShared::calculate_oopmap(MemRegion region) {
1051 assert(UseCompressedOops, "must be");
1052 size_t num_bits = region.byte_size() / sizeof(narrowOop);
1053 ResourceBitMap oopmap(num_bits);
1054
1055 HeapWord* p = region.start();
1056 HeapWord* end = region.end();
1057 FindEmbeddedNonNullPointers finder((narrowOop*)p, &oopmap);
1058
1059 int num_objs = 0;
1060 while (p < end) {
1061 oop o = (oop)p;
1062 o->oop_iterate(&finder);
1063 p += o->size();
1064 ++ num_objs;
1065 }
1066
1067 log_info(cds, heap)("calculate_oopmap: objects = %6d, embedded oops = %7d, nulls = %7d",
1068 num_objs, finder.num_total_oops(), finder.num_null_oops());
1069 return oopmap;
1070 }
1071
1072 // Patch all the embedded oop pointers inside an archived heap region,
1073 // to be consistent with the runtime oop encoding.
1074 class PatchEmbeddedPointers: public BitMapClosure {
1075 narrowOop* _start;
1076
1077 public:
1078 PatchEmbeddedPointers(narrowOop* start) : _start(start) {}
1079
1080 bool do_bit(size_t offset) {
1081 narrowOop* p = _start + offset;
1082 narrowOop v = *p;
1083 assert(!CompressedOops::is_null(v), "null oops should have been filtered out at dump time");
1084 oop o = HeapShared::decode_from_archive(v);
1085 RawAccess<IS_NOT_NULL>::oop_store(p, o);
1086 return true;
1087 }
1088 };
1089
1090 void HeapShared::patch_archived_heap_embedded_pointers(MemRegion region, address oopmap,
1091 size_t oopmap_size_in_bits) {
1092 BitMapView bm((BitMap::bm_word_t*)oopmap, oopmap_size_in_bits);
1093
1094 #ifndef PRODUCT
1095 ResourceMark rm;
1096 ResourceBitMap checkBm = calculate_oopmap(region);
1097 assert(bm.is_same(checkBm), "sanity");
1098 #endif
1099
1100 PatchEmbeddedPointers patcher((narrowOop*)region.start());
1101 bm.iterate(&patcher);
1102 }
1103
1104 #endif // INCLUDE_CDS_JAVA_HEAP