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/classLoaderData.hpp"
27 #include "classfile/classLoaderDataShared.hpp"
28 #include "classfile/javaClasses.inline.hpp"
29 #include "classfile/moduleEntry.hpp"
30 #include "classfile/stringTable.hpp"
31 #include "classfile/symbolTable.hpp"
32 #include "classfile/systemDictionary.hpp"
33 #include "classfile/systemDictionaryShared.hpp"
34 #include "classfile/vmSymbols.hpp"
35 #include "gc/shared/gcLocker.hpp"
36 #include "logging/log.hpp"
37 #include "logging/logMessage.hpp"
38 #include "logging/logStream.hpp"
39 #include "memory/archiveUtils.hpp"
40 #include "memory/filemap.hpp"
41 #include "memory/heapShared.inline.hpp"
42 #include "memory/iterator.inline.hpp"
43 #include "memory/metadataFactory.hpp"
44 #include "memory/metaspaceClosure.hpp"
45 #include "memory/metaspaceShared.hpp"
46 #include "memory/resourceArea.hpp"
47 #include "memory/universe.hpp"
48 #include "oops/compressedOops.inline.hpp"
49 #include "oops/fieldStreams.inline.hpp"
50 #include "oops/oop.inline.hpp"
51 #include "runtime/fieldDescriptor.inline.hpp"
52 #include "runtime/javaCalls.hpp"
53 #include "runtime/safepointVerifiers.hpp"
54 #include "utilities/bitMap.inline.hpp"
55 #if INCLUDE_G1GC
56 #include "gc/g1/g1CollectedHeap.hpp"
57 #endif
58
59 #if INCLUDE_CDS_JAVA_HEAP
60
61 bool HeapShared::_closed_archive_heap_region_mapped = false;
62 bool HeapShared::_open_archive_heap_region_mapped = false;
63 bool HeapShared::_archive_heap_region_fixed = false;
64
65 address HeapShared::_narrow_oop_base;
66 int HeapShared::_narrow_oop_shift;
67
68 //
69 // If you add new entries to the following tables, you should know what you're doing!
70 //
71
72 // Entry fields for shareable subgraphs archived in the closed archive heap
73 // region. Warning: Objects in the subgraphs should not have reference fields
74 // assigned at runtime.
75 static ArchivableStaticFieldInfo closed_archive_subgraph_entry_fields[] = {
76 {"java/lang/Integer$IntegerCache", 0, "archivedCache"},
77 {"java/lang/Long$LongCache", 0, "archivedCache"},
78 {"java/lang/Byte$ByteCache", 0, "archivedCache"},
79 {"java/lang/Short$ShortCache", 0, "archivedCache"},
80 {"java/lang/Character$CharacterCache", 0, "archivedCache"},
81 {"java/util/jar/Attributes$Name", 0, "KNOWN_NAMES"},
82 {"sun/util/locale/BaseLocale", 0, "constantBaseLocales"},
83 };
84 // Entry fields for subgraphs archived in the open archive heap region.
85 static ArchivableStaticFieldInfo open_archive_subgraph_entry_fields[] = {
86 {"jdk/internal/loader/ArchivedClassLoaders", 1, "archivedClassLoaders"},
87 {"jdk/internal/module/ArchivedBootLayer", 1, "archivedBootLayer"},
88 {"jdk/internal/module/ArchivedModuleGraph", 0, "archivedModuleGraph"},
89 {"java/util/ImmutableCollections", 0, "archivedObjects"},
90 {"java/lang/Module$ArchivedData", 1, "archivedData"},
91 {"java/lang/module/Configuration", 0, "EMPTY_CONFIGURATION"},
92 {"jdk/internal/math/FDBigInteger", 0, "archivedCaches"},
93 };
94
95 const static int num_closed_archive_subgraph_entry_fields =
96 sizeof(closed_archive_subgraph_entry_fields) / sizeof(ArchivableStaticFieldInfo);
97 const static int num_open_archive_subgraph_entry_fields =
98 sizeof(open_archive_subgraph_entry_fields) / sizeof(ArchivableStaticFieldInfo);
99
100 ////////////////////////////////////////////////////////////////
101 //
102 // Java heap object archiving support
103 //
104 ////////////////////////////////////////////////////////////////
105 void HeapShared::fixup_mapped_heap_regions() {
106 FileMapInfo *mapinfo = FileMapInfo::current_info();
107 mapinfo->fixup_mapped_heap_regions();
108 set_archive_heap_region_fixed();
109 SystemDictionaryShared::update_archived_mirror_native_pointers();
110 }
111
112 unsigned HeapShared::oop_hash(oop const& p) {
113 assert(!p->mark().has_bias_pattern(),
114 "this object should never have been locked"); // so identity_hash won't safepoin
115 unsigned hash = (unsigned)p->identity_hash();
116 return hash;
117 }
118
119 static void reset_states(oop obj, TRAPS) {
120 Handle h_obj(THREAD, obj);
121 InstanceKlass* klass = InstanceKlass::cast(obj->klass());
122 TempNewSymbol method_name = SymbolTable::new_symbol("resetArchivedStates");
123 Symbol* method_sig = vmSymbols::void_method_signature();
124
125 while (klass != NULL) {
126 Method* method = klass->find_method(method_name, method_sig);
127 if (method != NULL) {
128 assert(method->is_private(), "must be");
129 if (log_is_enabled(Debug, cds)) {
130 ResourceMark rm(THREAD);
131 log_debug(cds)(" calling %s", method->name_and_sig_as_C_string());
132 }
133 JavaValue result(T_VOID);
134 JavaCalls::call_special(&result, h_obj, klass,
135 method_name, method_sig, CHECK);
136 }
137 klass = klass->java_super();
138 }
139 }
140
141 void HeapShared::reset_archived_object_states(TRAPS) {
142 assert(DumpSharedSpaces, "dump-time only");
143 log_debug(cds)("Resetting platform loader");
144 reset_states(SystemDictionary::java_platform_loader(), THREAD);
145 log_debug(cds)("Resetting system loader");
146 reset_states(SystemDictionary::java_system_loader(), THREAD);
147 }
148
149 HeapShared::ArchivedObjectCache* HeapShared::_archived_object_cache = NULL;
150 oop HeapShared::find_archived_heap_object(oop obj) {
151 assert(DumpSharedSpaces, "dump-time only");
152 ArchivedObjectCache* cache = archived_object_cache();
153 oop* p = cache->get(obj);
154 if (p != NULL) {
155 return *p;
156 } else {
157 return NULL;
158 }
159 }
160
161 oop HeapShared::archive_heap_object(oop obj, Thread* THREAD) {
162 assert(DumpSharedSpaces, "dump-time only");
163
164 oop ao = find_archived_heap_object(obj);
165 if (ao != NULL) {
166 // already archived
167 return ao;
168 }
169
170 int len = obj->size();
171 if (G1CollectedHeap::heap()->is_archive_alloc_too_large(len)) {
172 log_debug(cds, heap)("Cannot archive, object (" PTR_FORMAT ") is too large: " SIZE_FORMAT,
173 p2i(obj), (size_t)obj->size());
174 return NULL;
175 }
176
177 oop archived_oop = (oop)G1CollectedHeap::heap()->archive_mem_allocate(len);
178 if (archived_oop != NULL) {
179 Copy::aligned_disjoint_words(cast_from_oop<HeapWord*>(obj), cast_from_oop<HeapWord*>(archived_oop), len);
180 MetaspaceShared::relocate_klass_ptr(archived_oop);
181 // Reinitialize markword to remove age/marking/locking/etc.
182 //
183 // We need to retain the identity_hash, because it may have been used by some hashtables
184 // in the shared heap. This also has the side effect of pre-initializing the
185 // identity_hash for all shared objects, so they are less likely to be written
186 // into during run time, increasing the potential of memory sharing.
187 int hash_original = obj->identity_hash();
188 archived_oop->set_mark_raw(markWord::prototype().copy_set_hash(hash_original));
189 assert(archived_oop->mark().is_unlocked(), "sanity");
190
191 DEBUG_ONLY(int hash_archived = archived_oop->identity_hash());
192 assert(hash_original == hash_archived, "Different hash codes: original %x, archived %x", hash_original, hash_archived);
193
194 ArchivedObjectCache* cache = archived_object_cache();
195 cache->put(obj, archived_oop);
196 log_debug(cds, heap)("Archived heap object " PTR_FORMAT " ==> " PTR_FORMAT,
197 p2i(obj), p2i(archived_oop));
198 } else {
199 log_error(cds, heap)(
200 "Cannot allocate space for object " PTR_FORMAT " in archived heap region",
201 p2i(obj));
202 vm_exit(1);
203 }
204 return archived_oop;
205 }
206
207 oop HeapShared::materialize_archived_object(narrowOop v) {
208 assert(archive_heap_region_fixed(),
209 "must be called after archive heap regions are fixed");
210 if (!CompressedOops::is_null(v)) {
211 oop obj = HeapShared::decode_from_archive(v);
212 return G1CollectedHeap::heap()->materialize_archived_object(obj);
213 }
214 return NULL;
215 }
216
217 void HeapShared::archive_klass_objects(Thread* THREAD) {
218 GrowableArray<Klass*>* klasses = MetaspaceShared::collected_klasses();
219 assert(klasses != NULL, "sanity");
220 for (int i = 0; i < klasses->length(); i++) {
221 Klass* k = klasses->at(i);
222
223 // archive mirror object
224 java_lang_Class::archive_mirror(k, CHECK);
225
226 // archive the resolved_referenes array
227 if (k->is_instance_klass()) {
228 InstanceKlass* ik = InstanceKlass::cast(k);
229 ik->constants()->archive_resolved_references(THREAD);
230 }
231 }
232 }
233
234 void HeapShared::run_full_gc_in_vm_thread() {
235 if (is_heap_object_archiving_allowed()) {
236 // Avoid fragmentation while archiving heap objects.
237 // We do this inside a safepoint, so that no further allocation can happen after GC
238 // has finished.
239 if (GCLocker::is_active()) {
240 // Just checking for safety ...
241 // This should not happen during -Xshare:dump. If you see this, probably the Java core lib
242 // has been modified such that JNI code is executed in some clean up threads after
243 // we have finished class loading.
244 log_warning(cds)("GC locker is held, unable to start extra compacting GC. This may produce suboptimal results.");
245 } else {
246 log_info(cds)("Run GC ...");
247 Universe::heap()->collect_as_vm_thread(GCCause::_archive_time_gc);
248 log_info(cds)("Run GC done");
249 }
250 }
251 }
252
253 void HeapShared::archive_java_heap_objects(GrowableArray<MemRegion> *closed,
254 GrowableArray<MemRegion> *open) {
255 if (!is_heap_object_archiving_allowed()) {
256 log_info(cds)(
257 "Archived java heap is not supported as UseG1GC, "
258 "UseCompressedOops and UseCompressedClassPointers are required."
259 "Current settings: UseG1GC=%s, UseCompressedOops=%s, UseCompressedClassPointers=%s.",
260 BOOL_TO_STR(UseG1GC), BOOL_TO_STR(UseCompressedOops),
261 BOOL_TO_STR(UseCompressedClassPointers));
262 return;
263 }
264
265 G1HeapVerifier::verify_ready_for_archiving();
266
267 {
268 NoSafepointVerifier nsv;
269
270 // Cache for recording where the archived objects are copied to
271 create_archived_object_cache();
272
273 log_info(cds)("Dumping objects to closed archive heap region ...");
274 NOT_PRODUCT(StringTable::verify());
275 copy_closed_archive_heap_objects(closed);
276
277 log_info(cds)("Dumping objects to open archive heap region ...");
278 copy_open_archive_heap_objects(open);
279
280 ClassLoaderDataShared::init_archived_oops();
281
282 destroy_archived_object_cache();
283 }
284
285 G1HeapVerifier::verify_archive_regions();
286 }
287
288 void HeapShared::copy_closed_archive_heap_objects(
289 GrowableArray<MemRegion> * closed_archive) {
290 assert(is_heap_object_archiving_allowed(), "Cannot archive java heap objects");
291
292 Thread* THREAD = Thread::current();
293 G1CollectedHeap::heap()->begin_archive_alloc_range();
294
295 // Archive interned string objects
296 StringTable::write_to_archive();
297
298 archive_object_subgraphs(closed_archive_subgraph_entry_fields,
299 num_closed_archive_subgraph_entry_fields,
300 true /* is_closed_archive */, THREAD);
301
302 G1CollectedHeap::heap()->end_archive_alloc_range(closed_archive,
303 os::vm_allocation_granularity());
304 }
305
306 void HeapShared::copy_open_archive_heap_objects(
307 GrowableArray<MemRegion> * open_archive) {
308 assert(is_heap_object_archiving_allowed(), "Cannot archive java heap objects");
309
310 Thread* THREAD = Thread::current();
311 G1CollectedHeap::heap()->begin_archive_alloc_range(true /* open */);
312
313 java_lang_Class::archive_basic_type_mirrors(THREAD);
314
315 archive_klass_objects(THREAD);
316
317 archive_object_subgraphs(open_archive_subgraph_entry_fields,
318 num_open_archive_subgraph_entry_fields,
319 false /* is_closed_archive */,
320 THREAD);
321
322 G1CollectedHeap::heap()->end_archive_alloc_range(open_archive,
323 os::vm_allocation_granularity());
324 }
325
326 void HeapShared::init_narrow_oop_decoding(address base, int shift) {
327 _narrow_oop_base = base;
328 _narrow_oop_shift = shift;
329 }
330
331 //
332 // Subgraph archiving support
333 //
334 HeapShared::DumpTimeKlassSubGraphInfoTable* HeapShared::_dump_time_subgraph_info_table = NULL;
335 HeapShared::RunTimeKlassSubGraphInfoTable HeapShared::_run_time_subgraph_info_table;
336
337 // Get the subgraph_info for Klass k. A new subgraph_info is created if
338 // there is no existing one for k. The subgraph_info records the relocated
339 // Klass* of the original k.
340 KlassSubGraphInfo* HeapShared::get_subgraph_info(Klass* k) {
341 assert(DumpSharedSpaces, "dump time only");
342 Klass* relocated_k = MetaspaceShared::get_relocated_klass(k);
343 KlassSubGraphInfo* info = _dump_time_subgraph_info_table->get(relocated_k);
344 if (info == NULL) {
345 _dump_time_subgraph_info_table->put(relocated_k, KlassSubGraphInfo(relocated_k));
346 info = _dump_time_subgraph_info_table->get(relocated_k);
347 ++ _dump_time_subgraph_info_table->_count;
348 }
349 return info;
350 }
351
352 // Add an entry field to the current KlassSubGraphInfo.
353 void KlassSubGraphInfo::add_subgraph_entry_field(
354 int static_field_offset, oop v, bool is_closed_archive) {
355 assert(DumpSharedSpaces, "dump time only");
356 if (_subgraph_entry_fields == NULL) {
357 _subgraph_entry_fields =
358 new(ResourceObj::C_HEAP, mtClass) GrowableArray<juint>(10, mtClass);
359 }
360 _subgraph_entry_fields->append((juint)static_field_offset);
361 _subgraph_entry_fields->append(CompressedOops::encode(v));
362 _subgraph_entry_fields->append(is_closed_archive ? 1 : 0);
363 }
364
365 // Add the Klass* for an object in the current KlassSubGraphInfo's subgraphs.
366 // Only objects of boot classes can be included in sub-graph.
367 void KlassSubGraphInfo::add_subgraph_object_klass(Klass* orig_k, Klass *relocated_k) {
368 assert(DumpSharedSpaces, "dump time only");
369 assert(relocated_k == MetaspaceShared::get_relocated_klass(orig_k),
370 "must be the relocated Klass in the shared space");
371
372 if (_subgraph_object_klasses == NULL) {
373 _subgraph_object_klasses =
374 new(ResourceObj::C_HEAP, mtClass) GrowableArray<Klass*>(50, mtClass);
375 }
376
377 assert(relocated_k->is_shared(), "must be a shared class");
378
379 if (_k == relocated_k) {
380 // Don't add the Klass containing the sub-graph to it's own klass
381 // initialization list.
382 return;
383 }
384
385 if (relocated_k->is_instance_klass()) {
386 assert(InstanceKlass::cast(relocated_k)->is_shared_boot_class(),
387 "must be boot class");
388 // SystemDictionary::xxx_klass() are not updated, need to check
389 // the original Klass*
390 if (orig_k == SystemDictionary::String_klass() ||
391 orig_k == SystemDictionary::Object_klass()) {
392 // Initialized early during VM initialization. No need to be added
393 // to the sub-graph object class list.
394 return;
395 }
396 } else if (relocated_k->is_objArray_klass()) {
397 Klass* abk = ObjArrayKlass::cast(relocated_k)->bottom_klass();
398 if (abk->is_instance_klass()) {
399 assert(InstanceKlass::cast(abk)->is_shared_boot_class(),
400 "must be boot class");
401 }
402 if (relocated_k == Universe::objectArrayKlassObj()) {
403 // Initialized early during Universe::genesis. No need to be added
404 // to the list.
405 return;
406 }
407 } else {
408 assert(relocated_k->is_typeArray_klass(), "must be");
409 // Primitive type arrays are created early during Universe::genesis.
410 return;
411 }
412
413 if (log_is_enabled(Debug, cds, heap)) {
414 if (!_subgraph_object_klasses->contains(relocated_k)) {
415 ResourceMark rm;
416 log_debug(cds, heap)("Adding klass %s", orig_k->external_name());
417 }
418 }
419
420 _subgraph_object_klasses->append_if_missing(relocated_k);
421 }
422
423 // Initialize an archived subgraph_info_record from the given KlassSubGraphInfo.
424 void ArchivedKlassSubGraphInfoRecord::init(KlassSubGraphInfo* info) {
425 _k = info->klass();
426 _entry_field_records = NULL;
427 _subgraph_object_klasses = NULL;
428
429 // populate the entry fields
430 GrowableArray<juint>* entry_fields = info->subgraph_entry_fields();
431 if (entry_fields != NULL) {
432 int num_entry_fields = entry_fields->length();
433 assert(num_entry_fields % 3 == 0, "sanity");
434 _entry_field_records =
435 MetaspaceShared::new_ro_array<juint>(num_entry_fields);
436 for (int i = 0 ; i < num_entry_fields; i++) {
437 _entry_field_records->at_put(i, entry_fields->at(i));
438 }
439 }
440
441 // the Klasses of the objects in the sub-graphs
442 GrowableArray<Klass*>* subgraph_object_klasses = info->subgraph_object_klasses();
443 if (subgraph_object_klasses != NULL) {
444 int num_subgraphs_klasses = subgraph_object_klasses->length();
445 _subgraph_object_klasses =
446 MetaspaceShared::new_ro_array<Klass*>(num_subgraphs_klasses);
447 for (int i = 0; i < num_subgraphs_klasses; i++) {
448 Klass* subgraph_k = subgraph_object_klasses->at(i);
449 if (log_is_enabled(Info, cds, heap)) {
450 ResourceMark rm;
451 log_info(cds, heap)(
452 "Archived object klass %s (%2d) => %s",
453 _k->external_name(), i, subgraph_k->external_name());
454 }
455 _subgraph_object_klasses->at_put(i, subgraph_k);
456 ArchivePtrMarker::mark_pointer(_subgraph_object_klasses->adr_at(i));
457 }
458 }
459
460 ArchivePtrMarker::mark_pointer(&_k);
461 ArchivePtrMarker::mark_pointer(&_entry_field_records);
462 ArchivePtrMarker::mark_pointer(&_subgraph_object_klasses);
463 }
464
465 struct CopyKlassSubGraphInfoToArchive : StackObj {
466 CompactHashtableWriter* _writer;
467 CopyKlassSubGraphInfoToArchive(CompactHashtableWriter* writer) : _writer(writer) {}
468
469 bool do_entry(Klass* klass, KlassSubGraphInfo& info) {
470 if (info.subgraph_object_klasses() != NULL || info.subgraph_entry_fields() != NULL) {
471 ArchivedKlassSubGraphInfoRecord* record =
472 (ArchivedKlassSubGraphInfoRecord*)MetaspaceShared::read_only_space_alloc(sizeof(ArchivedKlassSubGraphInfoRecord));
473 record->init(&info);
474
475 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary(klass);
476 u4 delta = MetaspaceShared::object_delta_u4(record);
477 _writer->add(hash, delta);
478 }
479 return true; // keep on iterating
480 }
481 };
482
483 // Build the records of archived subgraph infos, which include:
484 // - Entry points to all subgraphs from the containing class mirror. The entry
485 // points are static fields in the mirror. For each entry point, the field
486 // offset, value and is_closed_archive flag are recorded in the sub-graph
487 // info. The value is stored back to the corresponding field at runtime.
488 // - A list of klasses that need to be loaded/initialized before archived
489 // java object sub-graph can be accessed at runtime.
490 void HeapShared::write_subgraph_info_table() {
491 // Allocate the contents of the hashtable(s) inside the RO region of the CDS archive.
492 DumpTimeKlassSubGraphInfoTable* d_table = _dump_time_subgraph_info_table;
493 CompactHashtableStats stats;
494
495 _run_time_subgraph_info_table.reset();
496
497 CompactHashtableWriter writer(d_table->_count, &stats);
498 CopyKlassSubGraphInfoToArchive copy(&writer);
499 d_table->iterate(©);
500
501 writer.dump(&_run_time_subgraph_info_table, "subgraphs");
502 }
503
504 void HeapShared::serialize_subgraph_info_table_header(SerializeClosure* soc) {
505 _run_time_subgraph_info_table.serialize_header(soc);
506 }
507
508 void HeapShared::initialize_from_archived_subgraph(Klass* k) {
509 if (!open_archive_heap_region_mapped()) {
510 return; // nothing to do
511 }
512 assert(!DumpSharedSpaces, "Should not be called with DumpSharedSpaces");
513
514 if (!MetaspaceShared::use_full_module_graph()) {
515 for (int i = 0; i < num_open_archive_subgraph_entry_fields; i++) {
516 const ArchivableStaticFieldInfo* info = &open_archive_subgraph_entry_fields[i];
517 if (info->full_module_graph_only && k->name()->equals(info->klass_name)) {
518 return;
519 }
520 }
521 }
522
523 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary(k);
524 const ArchivedKlassSubGraphInfoRecord* record = _run_time_subgraph_info_table.lookup(k, hash, 0);
525
526 // Initialize from archived data. Currently this is done only
527 // during VM initialization time. No lock is needed.
528 if (record != NULL) {
529 Thread* THREAD = Thread::current();
530
531 int i;
532 // Load/link/initialize the klasses of the objects in the subgraph.
533 // NULL class loader is used.
534 Array<Klass*>* klasses = record->subgraph_object_klasses();
535 if (klasses != NULL) {
536 for (i = 0; i < klasses->length(); i++) {
537 Klass* obj_k = klasses->at(i);
538 Klass* resolved_k = SystemDictionary::resolve_or_null(
539 (obj_k)->name(), THREAD);
540 if (resolved_k != obj_k) {
541 assert(!SystemDictionary::is_well_known_klass(resolved_k),
542 "shared well-known classes must not be replaced by JVMTI ClassFileLoadHook");
543 ResourceMark rm(THREAD);
544 log_info(cds, heap)("Failed to load subgraph because %s was not loaded from archive",
545 resolved_k->external_name());
546 return;
547 }
548 if ((obj_k)->is_instance_klass()) {
549 InstanceKlass* ik = InstanceKlass::cast(obj_k);
550 ik->initialize(THREAD);
551 } else if ((obj_k)->is_objArray_klass()) {
552 ObjArrayKlass* oak = ObjArrayKlass::cast(obj_k);
553 oak->initialize(THREAD);
554 }
555 }
556 }
557
558 if (HAS_PENDING_EXCEPTION) {
559 CLEAR_PENDING_EXCEPTION;
560 // None of the field value will be set if there was an exception.
561 // The java code will not see any of the archived objects in the
562 // subgraphs referenced from k in this case.
563 return;
564 }
565
566 // Load the subgraph entry fields from the record and store them back to
567 // the corresponding fields within the mirror.
568 oop m = k->java_mirror();
569 Array<juint>* entry_field_records = record->entry_field_records();
570 if (entry_field_records != NULL) {
571 int efr_len = entry_field_records->length();
572 assert(efr_len % 3 == 0, "sanity");
573 for (i = 0; i < efr_len;) {
574 int field_offset = entry_field_records->at(i);
575 narrowOop nv = entry_field_records->at(i+1);
576 int is_closed_archive = entry_field_records->at(i+2);
577 oop v;
578 if (is_closed_archive == 0) {
579 // It's an archived object in the open archive heap regions, not shared.
580 // The object refereced by the field becomes 'known' by GC from this
581 // point. All objects in the subgraph reachable from the object are
582 // also 'known' by GC.
583 v = materialize_archived_object(nv);
584 } else {
585 // Shared object in the closed archive heap regions. Decode directly.
586 assert(!CompressedOops::is_null(nv), "shared object is null");
587 v = HeapShared::decode_from_archive(nv);
588 }
589 m->obj_field_put(field_offset, v);
590 i += 3;
591
592 log_debug(cds, heap)(" " PTR_FORMAT " init field @ %2d = " PTR_FORMAT, p2i(k), field_offset, p2i(v));
593 }
594
595 // Done. Java code can see the archived sub-graphs referenced from k's
596 // mirror after this point.
597 if (log_is_enabled(Info, cds, heap)) {
598 ResourceMark rm;
599 log_info(cds, heap)("initialize_from_archived_subgraph %s " PTR_FORMAT,
600 k->external_name(), p2i(k));
601 }
602 }
603 }
604 }
605
606 class WalkOopAndArchiveClosure: public BasicOopIterateClosure {
607 int _level;
608 bool _is_closed_archive;
609 bool _record_klasses_only;
610 KlassSubGraphInfo* _subgraph_info;
611 oop _orig_referencing_obj;
612 oop _archived_referencing_obj;
613 Thread* _thread;
614 public:
615 WalkOopAndArchiveClosure(int level,
616 bool is_closed_archive,
617 bool record_klasses_only,
618 KlassSubGraphInfo* subgraph_info,
619 oop orig, oop archived, TRAPS) :
620 _level(level), _is_closed_archive(is_closed_archive),
621 _record_klasses_only(record_klasses_only),
622 _subgraph_info(subgraph_info),
623 _orig_referencing_obj(orig), _archived_referencing_obj(archived),
624 _thread(THREAD) {}
625 void do_oop(narrowOop *p) { WalkOopAndArchiveClosure::do_oop_work(p); }
626 void do_oop( oop *p) { WalkOopAndArchiveClosure::do_oop_work(p); }
627
628 protected:
629 template <class T> void do_oop_work(T *p) {
630 oop obj = RawAccess<>::oop_load(p);
631 if (!CompressedOops::is_null(obj)) {
632 assert(!HeapShared::is_archived_object(obj),
633 "original objects must not point to archived objects");
634
635 size_t field_delta = pointer_delta(p, _orig_referencing_obj, sizeof(char));
636 T* new_p = (T*)(cast_from_oop<address>(_archived_referencing_obj) + field_delta);
637 Thread* THREAD = _thread;
638
639 if (!_record_klasses_only && log_is_enabled(Debug, cds, heap)) {
640 ResourceMark rm;
641 log_debug(cds, heap)("(%d) %s[" SIZE_FORMAT "] ==> " PTR_FORMAT " size %d %s", _level,
642 _orig_referencing_obj->klass()->external_name(), field_delta,
643 p2i(obj), obj->size() * HeapWordSize, obj->klass()->external_name());
644 LogTarget(Trace, cds, heap) log;
645 LogStream out(log);
646 obj->print_on(&out);
647 }
648
649 oop archived = HeapShared::archive_reachable_objects_from(
650 _level + 1, _subgraph_info, obj, _is_closed_archive, THREAD);
651 assert(archived != NULL, "VM should have exited with unarchivable objects for _level > 1");
652 assert(HeapShared::is_archived_object(archived), "must be");
653
654 if (!_record_klasses_only) {
655 // Update the reference in the archived copy of the referencing object.
656 log_debug(cds, heap)("(%d) updating oop @[" PTR_FORMAT "] " PTR_FORMAT " ==> " PTR_FORMAT,
657 _level, p2i(new_p), p2i(obj), p2i(archived));
658 RawAccess<IS_NOT_NULL>::oop_store(new_p, archived);
659 }
660 }
661 }
662 };
663
664 void HeapShared::check_closed_archive_heap_region_object(InstanceKlass* k,
665 Thread* THREAD) {
666 // Check fields in the object
667 for (JavaFieldStream fs(k); !fs.done(); fs.next()) {
668 if (!fs.access_flags().is_static()) {
669 BasicType ft = fs.field_descriptor().field_type();
670 if (!fs.access_flags().is_final() && is_reference_type(ft)) {
671 ResourceMark rm(THREAD);
672 log_warning(cds, heap)(
673 "Please check reference field in %s instance in closed archive heap region: %s %s",
674 k->external_name(), (fs.name())->as_C_string(),
675 (fs.signature())->as_C_string());
676 }
677 }
678 }
679 }
680
681 void HeapShared::check_module_oop(oop orig_module_obj) {
682 assert(DumpSharedSpaces, "must be");
683 assert(java_lang_Module::is_instance(orig_module_obj), "must be");
684 ModuleEntry* orig_module_ent = java_lang_Module::module_entry_raw(orig_module_obj);
685 if (orig_module_ent == NULL) {
686 // These special Module objects are created in Java code. They are not
687 // defined via Modules::define_module(), so they don't have a ModuleEntry:
688 // java.lang.Module::ALL_UNNAMED_MODULE
689 // java.lang.Module::EVERYONE_MODULE
690 // jdk.internal.loader.ClassLoaders$BootClassLoader::unnamedModule
691 assert(java_lang_Module::name(orig_module_obj) == NULL, "must be unnamed");
692 log_info(cds, heap)("Module oop with No ModuleEntry* @[" PTR_FORMAT "]", p2i(orig_module_obj));
693 } else {
694 ClassLoaderData* loader_data = orig_module_ent->loader_data();
695 assert(loader_data->is_builtin_class_loader_data(), "must be");
696 }
697 }
698
699
700 // (1) If orig_obj has not been archived yet, archive it.
701 // (2) If orig_obj has not been seen yet (since start_recording_subgraph() was called),
702 // trace all objects that are reachable from it, and make sure these objects are archived.
703 // (3) Record the klasses of all orig_obj and all reachable objects.
704 oop HeapShared::archive_reachable_objects_from(int level,
705 KlassSubGraphInfo* subgraph_info,
706 oop orig_obj,
707 bool is_closed_archive,
708 TRAPS) {
709 assert(orig_obj != NULL, "must be");
710 assert(!is_archived_object(orig_obj), "sanity");
711
712 if (!JavaClasses::is_supported_for_archiving(orig_obj)) {
713 // This object has injected fields that cannot be supported easily, so we disallow them for now.
714 // If you get an error here, you probably made a change in the JDK library that has added
715 // these objects that are referenced (directly or indirectly) by static fields.
716 ResourceMark rm;
717 log_error(cds, heap)("Cannot archive object of class %s", orig_obj->klass()->external_name());
718 vm_exit(1);
719 }
720
721 // java.lang.Class instances cannot be included in an archived object sub-graph. We only support
722 // them as Klass::_archived_mirror because they need to be specially restored at run time.
723 //
724 // If you get an error here, you probably made a change in the JDK library that has added a Class
725 // object that is referenced (directly or indirectly) by static fields.
726 if (java_lang_Class::is_instance(orig_obj)) {
727 log_error(cds, heap)("(%d) Unknown java.lang.Class object is in the archived sub-graph", level);
728 vm_exit(1);
729 }
730
731 oop archived_obj = find_archived_heap_object(orig_obj);
732 if (java_lang_String::is_instance(orig_obj) && archived_obj != NULL) {
733 // To save time, don't walk strings that are already archived. They just contain
734 // pointers to a type array, whose klass doesn't need to be recorded.
735 return archived_obj;
736 }
737
738 if (has_been_seen_during_subgraph_recording(orig_obj)) {
739 // orig_obj has already been archived and traced. Nothing more to do.
740 return archived_obj;
741 } else {
742 set_has_been_seen_during_subgraph_recording(orig_obj);
743 }
744
745 bool record_klasses_only = (archived_obj != NULL);
746 if (archived_obj == NULL) {
747 ++_num_new_archived_objs;
748 archived_obj = archive_heap_object(orig_obj, THREAD);
749 if (archived_obj == NULL) {
750 // Skip archiving the sub-graph referenced from the current entry field.
751 ResourceMark rm;
752 log_error(cds, heap)(
753 "Cannot archive the sub-graph referenced from %s object ("
754 PTR_FORMAT ") size %d, skipped.",
755 orig_obj->klass()->external_name(), p2i(orig_obj), orig_obj->size() * HeapWordSize);
756 if (level == 1) {
757 // Don't archive a subgraph root that's too big. For archives static fields, that's OK
758 // as the Java code will take care of initializing this field dynamically.
759 return NULL;
760 } else {
761 // We don't know how to handle an object that has been archived, but some of its reachable
762 // objects cannot be archived. Bail out for now. We might need to fix this in the future if
763 // we have a real use case.
764 vm_exit(1);
765 }
766 }
767
768 if (java_lang_Module::is_instance(orig_obj)) {
769 check_module_oop(orig_obj);
770 java_lang_Module::set_module_entry(archived_obj, NULL);
771 java_lang_Module::set_loader(archived_obj, NULL);
772 } else if (java_lang_ClassLoader::is_instance(orig_obj)) {
773 // class_data will be restored explicitly at run time.
774 guarantee(orig_obj == SystemDictionary::java_platform_loader() ||
775 orig_obj == SystemDictionary::java_system_loader() ||
776 java_lang_ClassLoader::loader_data_raw(orig_obj) == NULL, "must be");
777 java_lang_ClassLoader::release_set_loader_data(archived_obj, NULL);
778 }
779 }
780
781 assert(archived_obj != NULL, "must be");
782 Klass *orig_k = orig_obj->klass();
783 Klass *relocated_k = archived_obj->klass();
784 subgraph_info->add_subgraph_object_klass(orig_k, relocated_k);
785
786 WalkOopAndArchiveClosure walker(level, is_closed_archive, record_klasses_only,
787 subgraph_info, orig_obj, archived_obj, THREAD);
788 orig_obj->oop_iterate(&walker);
789 if (is_closed_archive && orig_k->is_instance_klass()) {
790 check_closed_archive_heap_region_object(InstanceKlass::cast(orig_k), THREAD);
791 }
792 return archived_obj;
793 }
794
795 //
796 // Start from the given static field in a java mirror and archive the
797 // complete sub-graph of java heap objects that are reached directly
798 // or indirectly from the starting object by following references.
799 // Sub-graph archiving restrictions (current):
800 //
801 // - All classes of objects in the archived sub-graph (including the
802 // entry class) must be boot class only.
803 // - No java.lang.Class instance (java mirror) can be included inside
804 // an archived sub-graph. Mirror can only be the sub-graph entry object.
805 //
806 // The Java heap object sub-graph archiving process (see
807 // WalkOopAndArchiveClosure):
808 //
809 // 1) Java object sub-graph archiving starts from a given static field
810 // within a Class instance (java mirror). If the static field is a
811 // refererence field and points to a non-null java object, proceed to
812 // the next step.
813 //
814 // 2) Archives the referenced java object. If an archived copy of the
815 // current object already exists, updates the pointer in the archived
816 // copy of the referencing object to point to the current archived object.
817 // Otherwise, proceed to the next step.
818 //
819 // 3) Follows all references within the current java object and recursively
820 // archive the sub-graph of objects starting from each reference.
821 //
822 // 4) Updates the pointer in the archived copy of referencing object to
823 // point to the current archived object.
824 //
825 // 5) The Klass of the current java object is added to the list of Klasses
826 // for loading and initialzing before any object in the archived graph can
827 // be accessed at runtime.
828 //
829 void HeapShared::archive_reachable_objects_from_static_field(InstanceKlass *k,
830 const char* klass_name,
831 int field_offset,
832 const char* field_name,
833 bool is_closed_archive,
834 TRAPS) {
835 assert(DumpSharedSpaces, "dump time only");
836 assert(k->is_shared_boot_class(), "must be boot class");
837
838 oop m = k->java_mirror();
839
840 KlassSubGraphInfo* subgraph_info = get_subgraph_info(k);
841 oop f = m->obj_field(field_offset);
842
843 log_debug(cds, heap)("Start archiving from: %s::%s (" PTR_FORMAT ")", klass_name, field_name, p2i(f));
844
845 if (!CompressedOops::is_null(f)) {
846 if (log_is_enabled(Trace, cds, heap)) {
847 LogTarget(Trace, cds, heap) log;
848 LogStream out(log);
849 f->print_on(&out);
850 }
851
852 oop af = archive_reachable_objects_from(1, subgraph_info, f,
853 is_closed_archive, CHECK);
854
855 if (af == NULL) {
856 log_error(cds, heap)("Archiving failed %s::%s (some reachable objects cannot be archived)",
857 klass_name, field_name);
858 } else {
859 // Note: the field value is not preserved in the archived mirror.
860 // Record the field as a new subGraph entry point. The recorded
861 // information is restored from the archive at runtime.
862 subgraph_info->add_subgraph_entry_field(field_offset, af, is_closed_archive);
863 log_info(cds, heap)("Archived field %s::%s => " PTR_FORMAT, klass_name, field_name, p2i(af));
864 }
865 } else {
866 // The field contains null, we still need to record the entry point,
867 // so it can be restored at runtime.
868 subgraph_info->add_subgraph_entry_field(field_offset, NULL, false);
869 }
870 }
871
872 #ifndef PRODUCT
873 class VerifySharedOopClosure: public BasicOopIterateClosure {
874 private:
875 bool _is_archived;
876
877 public:
878 VerifySharedOopClosure(bool is_archived) : _is_archived(is_archived) {}
879
880 void do_oop(narrowOop *p) { VerifySharedOopClosure::do_oop_work(p); }
881 void do_oop( oop *p) { VerifySharedOopClosure::do_oop_work(p); }
882
883 protected:
884 template <class T> void do_oop_work(T *p) {
885 oop obj = RawAccess<>::oop_load(p);
886 if (!CompressedOops::is_null(obj)) {
887 HeapShared::verify_reachable_objects_from(obj, _is_archived);
888 }
889 }
890 };
891
892 void HeapShared::verify_subgraph_from_static_field(InstanceKlass* k, int field_offset) {
893 assert(DumpSharedSpaces, "dump time only");
894 assert(k->is_shared_boot_class(), "must be boot class");
895
896 oop m = k->java_mirror();
897 oop f = m->obj_field(field_offset);
898 if (!CompressedOops::is_null(f)) {
899 verify_subgraph_from(f);
900 }
901 }
902
903 void HeapShared::verify_subgraph_from(oop orig_obj) {
904 oop archived_obj = find_archived_heap_object(orig_obj);
905 if (archived_obj == NULL) {
906 // It's OK for the root of a subgraph to be not archived. See comments in
907 // archive_reachable_objects_from().
908 return;
909 }
910
911 // Verify that all objects reachable from orig_obj are archived.
912 init_seen_objects_table();
913 verify_reachable_objects_from(orig_obj, false);
914 delete_seen_objects_table();
915
916 // Note: we could also verify that all objects reachable from the archived
917 // copy of orig_obj can only point to archived objects, with:
918 // init_seen_objects_table();
919 // verify_reachable_objects_from(archived_obj, true);
920 // init_seen_objects_table();
921 // but that's already done in G1HeapVerifier::verify_archive_regions so we
922 // won't do it here.
923 }
924
925 void HeapShared::verify_reachable_objects_from(oop obj, bool is_archived) {
926 _num_total_verifications ++;
927 if (!has_been_seen_during_subgraph_recording(obj)) {
928 set_has_been_seen_during_subgraph_recording(obj);
929
930 if (is_archived) {
931 assert(is_archived_object(obj), "must be");
932 assert(find_archived_heap_object(obj) == NULL, "must be");
933 } else {
934 assert(!is_archived_object(obj), "must be");
935 assert(find_archived_heap_object(obj) != NULL, "must be");
936 }
937
938 VerifySharedOopClosure walker(is_archived);
939 obj->oop_iterate(&walker);
940 }
941 }
942 #endif
943
944 HeapShared::SeenObjectsTable* HeapShared::_seen_objects_table = NULL;
945 int HeapShared::_num_new_walked_objs;
946 int HeapShared::_num_new_archived_objs;
947 int HeapShared::_num_old_recorded_klasses;
948
949 int HeapShared::_num_total_subgraph_recordings = 0;
950 int HeapShared::_num_total_walked_objs = 0;
951 int HeapShared::_num_total_archived_objs = 0;
952 int HeapShared::_num_total_recorded_klasses = 0;
953 int HeapShared::_num_total_verifications = 0;
954
955 bool HeapShared::has_been_seen_during_subgraph_recording(oop obj) {
956 return _seen_objects_table->get(obj) != NULL;
957 }
958
959 void HeapShared::set_has_been_seen_during_subgraph_recording(oop obj) {
960 assert(!has_been_seen_during_subgraph_recording(obj), "sanity");
961 _seen_objects_table->put(obj, true);
962 ++ _num_new_walked_objs;
963 }
964
965 void HeapShared::start_recording_subgraph(InstanceKlass *k, const char* class_name) {
966 log_info(cds, heap)("Start recording subgraph(s) for archived fields in %s", class_name);
967 init_seen_objects_table();
968 _num_new_walked_objs = 0;
969 _num_new_archived_objs = 0;
970 _num_old_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses();
971 }
972
973 void HeapShared::done_recording_subgraph(InstanceKlass *k, const char* class_name) {
974 int num_new_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses() -
975 _num_old_recorded_klasses;
976 log_info(cds, heap)("Done recording subgraph(s) for archived fields in %s: "
977 "walked %d objs, archived %d new objs, recorded %d classes",
978 class_name, _num_new_walked_objs, _num_new_archived_objs,
979 num_new_recorded_klasses);
980
981 delete_seen_objects_table();
982
983 _num_total_subgraph_recordings ++;
984 _num_total_walked_objs += _num_new_walked_objs;
985 _num_total_archived_objs += _num_new_archived_objs;
986 _num_total_recorded_klasses += num_new_recorded_klasses;
987 }
988
989 class ArchivableStaticFieldFinder: public FieldClosure {
990 InstanceKlass* _ik;
991 Symbol* _field_name;
992 bool _found;
993 int _offset;
994 public:
995 ArchivableStaticFieldFinder(InstanceKlass* ik, Symbol* field_name) :
996 _ik(ik), _field_name(field_name), _found(false), _offset(-1) {}
997
998 virtual void do_field(fieldDescriptor* fd) {
999 if (fd->name() == _field_name) {
1000 assert(!_found, "fields cannot be overloaded");
1001 assert(is_reference_type(fd->field_type()), "can archive only fields that are references");
1002 _found = true;
1003 _offset = fd->offset();
1004 }
1005 }
1006 bool found() { return _found; }
1007 int offset() { return _offset; }
1008 };
1009
1010 void HeapShared::init_subgraph_entry_fields(ArchivableStaticFieldInfo fields[],
1011 int num, Thread* THREAD) {
1012 for (int i = 0; i < num; i++) {
1013 ArchivableStaticFieldInfo* info = &fields[i];
1014 TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name);
1015 TempNewSymbol field_name = SymbolTable::new_symbol(info->field_name);
1016
1017 Klass* k = SystemDictionary::resolve_or_null(klass_name, THREAD);
1018 assert(k != NULL && !HAS_PENDING_EXCEPTION, "class must exist");
1019 InstanceKlass* ik = InstanceKlass::cast(k);
1020 assert(InstanceKlass::cast(ik)->is_shared_boot_class(),
1021 "Only support boot classes");
1022 ik->initialize(THREAD);
1023 guarantee(!HAS_PENDING_EXCEPTION, "exception in initialize");
1024
1025 ArchivableStaticFieldFinder finder(ik, field_name);
1026 ik->do_local_static_fields(&finder);
1027 assert(finder.found(), "field must exist");
1028
1029 info->klass = ik;
1030 info->offset = finder.offset();
1031 }
1032 }
1033
1034 void HeapShared::init_subgraph_entry_fields(Thread* THREAD) {
1035 _dump_time_subgraph_info_table = new (ResourceObj::C_HEAP, mtClass)DumpTimeKlassSubGraphInfoTable();
1036
1037 init_subgraph_entry_fields(closed_archive_subgraph_entry_fields,
1038 num_closed_archive_subgraph_entry_fields,
1039 THREAD);
1040 init_subgraph_entry_fields(open_archive_subgraph_entry_fields,
1041 num_open_archive_subgraph_entry_fields,
1042 THREAD);
1043 }
1044
1045 void HeapShared::archive_object_subgraphs(ArchivableStaticFieldInfo fields[],
1046 int num, bool is_closed_archive,
1047 Thread* THREAD) {
1048 _num_total_subgraph_recordings = 0;
1049 _num_total_walked_objs = 0;
1050 _num_total_archived_objs = 0;
1051 _num_total_recorded_klasses = 0;
1052 _num_total_verifications = 0;
1053
1054 // For each class X that has one or more archived fields:
1055 // [1] Dump the subgraph of each archived field
1056 // [2] Create a list of all the class of the objects that can be reached
1057 // by any of these static fields.
1058 // At runtime, these classes are initialized before X's archived fields
1059 // are restored by HeapShared::initialize_from_archived_subgraph().
1060 int i;
1061 for (i = 0; i < num; ) {
1062 ArchivableStaticFieldInfo* info = &fields[i];
1063 const char* klass_name = info->klass_name;
1064 start_recording_subgraph(info->klass, klass_name);
1065
1066 // If you have specified consecutive fields of the same klass in
1067 // fields[], these will be archived in the same
1068 // {start_recording_subgraph ... done_recording_subgraph} pass to
1069 // save time.
1070 for (; i < num; i++) {
1071 ArchivableStaticFieldInfo* f = &fields[i];
1072 if (f->klass_name != klass_name) {
1073 break;
1074 }
1075
1076 if (!info->full_module_graph_only || MetaspaceShared::use_full_module_graph()) {
1077 archive_reachable_objects_from_static_field(f->klass, f->klass_name,
1078 f->offset, f->field_name,
1079 is_closed_archive, CHECK);
1080 }
1081 }
1082 done_recording_subgraph(info->klass, klass_name);
1083 }
1084
1085 log_info(cds, heap)("Archived subgraph records in %s archive heap region = %d",
1086 is_closed_archive ? "closed" : "open",
1087 _num_total_subgraph_recordings);
1088 log_info(cds, heap)(" Walked %d objects", _num_total_walked_objs);
1089 log_info(cds, heap)(" Archived %d objects", _num_total_archived_objs);
1090 log_info(cds, heap)(" Recorded %d klasses", _num_total_recorded_klasses);
1091
1092 #ifndef PRODUCT
1093 for (int i = 0; i < num; i++) {
1094 ArchivableStaticFieldInfo* f = &fields[i];
1095 verify_subgraph_from_static_field(f->klass, f->offset);
1096 }
1097 log_info(cds, heap)(" Verified %d references", _num_total_verifications);
1098 #endif
1099 }
1100
1101 // At dump-time, find the location of all the non-null oop pointers in an archived heap
1102 // region. This way we can quickly relocate all the pointers without using
1103 // BasicOopIterateClosure at runtime.
1104 class FindEmbeddedNonNullPointers: public BasicOopIterateClosure {
1105 narrowOop* _start;
1106 BitMap *_oopmap;
1107 int _num_total_oops;
1108 int _num_null_oops;
1109 public:
1110 FindEmbeddedNonNullPointers(narrowOop* start, BitMap* oopmap)
1111 : _start(start), _oopmap(oopmap), _num_total_oops(0), _num_null_oops(0) {}
1112
1113 virtual bool should_verify_oops(void) {
1114 return false;
1115 }
1116 virtual void do_oop(narrowOop* p) {
1117 _num_total_oops ++;
1118 narrowOop v = *p;
1119 if (!CompressedOops::is_null(v)) {
1120 size_t idx = p - _start;
1121 _oopmap->set_bit(idx);
1122 } else {
1123 _num_null_oops ++;
1124 }
1125 }
1126 virtual void do_oop(oop *p) {
1127 ShouldNotReachHere();
1128 }
1129 int num_total_oops() const { return _num_total_oops; }
1130 int num_null_oops() const { return _num_null_oops; }
1131 };
1132
1133 ResourceBitMap HeapShared::calculate_oopmap(MemRegion region) {
1134 assert(UseCompressedOops, "must be");
1135 size_t num_bits = region.byte_size() / sizeof(narrowOop);
1136 ResourceBitMap oopmap(num_bits);
1137
1138 HeapWord* p = region.start();
1139 HeapWord* end = region.end();
1140 FindEmbeddedNonNullPointers finder((narrowOop*)p, &oopmap);
1141
1142 int num_objs = 0;
1143 while (p < end) {
1144 oop o = (oop)p;
1145 o->oop_iterate(&finder);
1146 p += o->size();
1147 ++ num_objs;
1148 }
1149
1150 log_info(cds, heap)("calculate_oopmap: objects = %6d, embedded oops = %7d, nulls = %7d",
1151 num_objs, finder.num_total_oops(), finder.num_null_oops());
1152 return oopmap;
1153 }
1154
1155 // Patch all the embedded oop pointers inside an archived heap region,
1156 // to be consistent with the runtime oop encoding.
1157 class PatchEmbeddedPointers: public BitMapClosure {
1158 narrowOop* _start;
1159
1160 public:
1161 PatchEmbeddedPointers(narrowOop* start) : _start(start) {}
1162
1163 bool do_bit(size_t offset) {
1164 narrowOop* p = _start + offset;
1165 narrowOop v = *p;
1166 assert(!CompressedOops::is_null(v), "null oops should have been filtered out at dump time");
1167 oop o = HeapShared::decode_from_archive(v);
1168 RawAccess<IS_NOT_NULL>::oop_store(p, o);
1169 return true;
1170 }
1171 };
1172
1173 void HeapShared::patch_archived_heap_embedded_pointers(MemRegion region, address oopmap,
1174 size_t oopmap_size_in_bits) {
1175 BitMapView bm((BitMap::bm_word_t*)oopmap, oopmap_size_in_bits);
1176
1177 #ifndef PRODUCT
1178 ResourceMark rm;
1179 ResourceBitMap checkBm = calculate_oopmap(region);
1180 assert(bm.is_same(checkBm), "sanity");
1181 #endif
1182
1183 PatchEmbeddedPointers patcher((narrowOop*)region.start());
1184 bm.iterate(&patcher);
1185 }
1186
1187 #endif // INCLUDE_CDS_JAVA_HEAP