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