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