1 /*
2 * Copyright (c) 2018, 2020, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/javaClasses.inline.hpp"
27 #include "classfile/stringTable.hpp"
28 #include "classfile/symbolTable.hpp"
29 #include "classfile/systemDictionaryShared.hpp"
30 #include "classfile/vmSymbols.hpp"
31 #include "gc/shared/gcLocker.hpp"
32 #include "logging/log.hpp"
33 #include "logging/logMessage.hpp"
34 #include "logging/logStream.hpp"
35 #include "memory/archiveUtils.hpp"
36 #include "memory/filemap.hpp"
37 #include "memory/heapShared.inline.hpp"
38 #include "memory/iterator.inline.hpp"
39 #include "memory/metadataFactory.hpp"
40 #include "memory/metaspaceClosure.hpp"
41 #include "memory/metaspaceShared.hpp"
42 #include "memory/resourceArea.hpp"
43 #include "memory/universe.hpp"
44 #include "oops/compressedOops.inline.hpp"
45 #include "oops/fieldStreams.inline.hpp"
46 #include "oops/oop.inline.hpp"
47 #include "runtime/fieldDescriptor.inline.hpp"
48 #include "runtime/safepointVerifiers.hpp"
49 #include "utilities/bitMap.inline.hpp"
50 #if INCLUDE_G1GC
51 #include "gc/g1/g1CollectedHeap.hpp"
52 #endif
53
54 #if INCLUDE_CDS_JAVA_HEAP
55
56 bool HeapShared::_closed_archive_heap_region_mapped = false;
57 bool HeapShared::_open_archive_heap_region_mapped = false;
58 bool HeapShared::_archive_heap_region_fixed = false;
59
60 address HeapShared::_narrow_oop_base;
61 int HeapShared::_narrow_oop_shift;
62
63 //
64 // If you add new entries to the following tables, you should know what you're doing!
65 //
66
67 // Entry fields for shareable subgraphs archived in the closed archive heap
68 // region. Warning: Objects in the subgraphs should not have reference fields
69 // assigned at runtime.
70 static ArchivableStaticFieldInfo closed_archive_subgraph_entry_fields[] = {
71 {"java/lang/Integer$IntegerCache", "archivedCache"},
72 {"java/lang/Long$LongCache", "archivedCache"},
73 {"java/lang/Byte$ByteCache", "archivedCache"},
74 {"java/lang/Short$ShortCache", "archivedCache"},
75 {"java/lang/Character$CharacterCache", "archivedCache"},
76 {"java/util/jar/Attributes$Name", "KNOWN_NAMES"},
77 {"sun/util/locale/BaseLocale", "constantBaseLocales"},
78 };
79 // Entry fields for subgraphs archived in the open archive heap region.
80 static ArchivableStaticFieldInfo open_archive_subgraph_entry_fields[] = {
81 {"jdk/internal/module/ArchivedModuleGraph", "archivedModuleGraph"},
82 {"java/util/ImmutableCollections", "archivedObjects"},
83 {"java/lang/module/Configuration", "EMPTY_CONFIGURATION"},
84 {"jdk/internal/math/FDBigInteger", "archivedCaches"},
85 };
86
87 const static int num_closed_archive_subgraph_entry_fields =
88 sizeof(closed_archive_subgraph_entry_fields) / sizeof(ArchivableStaticFieldInfo);
89 const static int num_open_archive_subgraph_entry_fields =
90 sizeof(open_archive_subgraph_entry_fields) / sizeof(ArchivableStaticFieldInfo);
91
92 ////////////////////////////////////////////////////////////////
93 //
94 // Java heap object archiving support
95 //
96 ////////////////////////////////////////////////////////////////
97 void HeapShared::fixup_mapped_heap_regions() {
98 FileMapInfo *mapinfo = FileMapInfo::current_info();
99 mapinfo->fixup_mapped_heap_regions();
100 set_archive_heap_region_fixed();
101 SystemDictionaryShared::update_archived_mirror_native_pointers();
102 }
103
104 unsigned HeapShared::oop_hash(oop const& p) {
105 assert(!p->mark().has_bias_pattern(),
106 "this object should never have been locked"); // so identity_hash won't safepoin
107 unsigned hash = (unsigned)p->identity_hash();
108 return hash;
109 }
110
111 HeapShared::ArchivedObjectCache* HeapShared::_archived_object_cache = NULL;
112 oop HeapShared::find_archived_heap_object(oop obj) {
113 assert(DumpSharedSpaces, "dump-time only");
114 ArchivedObjectCache* cache = archived_object_cache();
115 oop* p = cache->get(obj);
116 if (p != NULL) {
117 return *p;
118 } else {
119 return NULL;
120 }
121 }
122
123 oop HeapShared::archive_heap_object(oop obj, Thread* THREAD) {
124 assert(DumpSharedSpaces, "dump-time only");
125
126 oop ao = find_archived_heap_object(obj);
127 if (ao != NULL) {
128 // already archived
129 return ao;
130 }
131
132 int len = obj->size();
133 if (G1CollectedHeap::heap()->is_archive_alloc_too_large(len)) {
134 log_debug(cds, heap)("Cannot archive, object (" PTR_FORMAT ") is too large: " SIZE_FORMAT,
135 p2i(obj), (size_t)obj->size());
136 return NULL;
137 }
138
139 // Pre-compute object identity hash at CDS dump time.
140 obj->identity_hash();
141
142 oop archived_oop = (oop)G1CollectedHeap::heap()->archive_mem_allocate(len);
143 if (archived_oop != NULL) {
144 Copy::aligned_disjoint_words(cast_from_oop<HeapWord*>(obj), cast_from_oop<HeapWord*>(archived_oop), len);
145 MetaspaceShared::relocate_klass_ptr(archived_oop);
146 // Clear age -- it might have been set if a GC happened during -Xshare:dump
147 markWord mark = archived_oop->mark_raw();
148 mark = mark.set_age(0);
149 archived_oop->set_mark_raw(mark);
150 ArchivedObjectCache* cache = archived_object_cache();
151 cache->put(obj, archived_oop);
152 log_debug(cds, heap)("Archived heap object " PTR_FORMAT " ==> " PTR_FORMAT,
153 p2i(obj), p2i(archived_oop));
154 } else {
155 log_error(cds, heap)(
156 "Cannot allocate space for object " PTR_FORMAT " in archived heap region",
157 p2i(obj));
158 vm_exit(1);
159 }
160 return archived_oop;
161 }
162
163 oop HeapShared::materialize_archived_object(narrowOop v) {
164 assert(archive_heap_region_fixed(),
165 "must be called after archive heap regions are fixed");
166 if (!CompressedOops::is_null(v)) {
167 oop obj = HeapShared::decode_from_archive(v);
168 return G1CollectedHeap::heap()->materialize_archived_object(obj);
169 }
170 return NULL;
171 }
172
173 void HeapShared::archive_klass_objects(Thread* THREAD) {
174 GrowableArray<Klass*>* klasses = MetaspaceShared::collected_klasses();
175 assert(klasses != NULL, "sanity");
176 for (int i = 0; i < klasses->length(); i++) {
177 Klass* k = klasses->at(i);
178
179 // archive mirror object
180 java_lang_Class::archive_mirror(k, CHECK);
181
182 // archive the resolved_referenes array
183 if (k->is_instance_klass()) {
184 InstanceKlass* ik = InstanceKlass::cast(k);
185 ik->constants()->archive_resolved_references(THREAD);
186 }
187 }
188 }
189
190 void HeapShared::run_gc() {
191 if (is_heap_object_archiving_allowed()) {
192 // Avoid fragmentation while archiving heap objects.
193 // We do this inside a safepoint, so that no further allocation can happen after GC
194 // has finished.
195 if (GCLocker::is_active()) {
196 // Just checking for safety ...
197 // This should not happen during -Xshare:dump. If you see this, probably the Java core lib
198 // has been modified such that JNI code is executed in some clean up threads after
199 // we have finished class loading.
200 log_warning(cds)("GC locker is held, unable to start extra compacting GC. This may produce suboptimal results.");
201 } else {
202 log_info(cds)("Run GC ...");
203 Universe::heap()->collect_as_vm_thread(GCCause::_archive_time_gc);
204 log_info(cds)("Run GC done");
205 }
206 }
207 }
208
209 void HeapShared::archive_java_heap_objects(GrowableArray<MemRegion> *closed,
210 GrowableArray<MemRegion> *open) {
211 if (!is_heap_object_archiving_allowed()) {
212 log_info(cds)(
213 "Archived java heap is not supported as UseG1GC, "
214 "UseCompressedOops and UseCompressedClassPointers are required."
215 "Current settings: UseG1GC=%s, UseCompressedOops=%s, UseCompressedClassPointers=%s.",
216 BOOL_TO_STR(UseG1GC), BOOL_TO_STR(UseCompressedOops),
217 BOOL_TO_STR(UseCompressedClassPointers));
218 return;
219 }
220
221 G1HeapVerifier::verify_ready_for_archiving();
222
223 {
224 NoSafepointVerifier nsv;
225
226 // Cache for recording where the archived objects are copied to
227 create_archived_object_cache();
228
229 log_info(cds)("Dumping objects to closed archive heap region ...");
230 NOT_PRODUCT(StringTable::verify());
231 copy_closed_archive_heap_objects(closed);
232
233 log_info(cds)("Dumping objects to open archive heap region ...");
234 copy_open_archive_heap_objects(open);
235
236 destroy_archived_object_cache();
237 }
238
239 G1HeapVerifier::verify_archive_regions();
240 }
241
242 void HeapShared::copy_closed_archive_heap_objects(
243 GrowableArray<MemRegion> * closed_archive) {
244 assert(is_heap_object_archiving_allowed(), "Cannot archive java heap objects");
245
246 Thread* THREAD = Thread::current();
247 G1CollectedHeap::heap()->begin_archive_alloc_range();
248
249 // Archive interned string objects
250 StringTable::write_to_archive();
251
252 archive_object_subgraphs(closed_archive_subgraph_entry_fields,
253 num_closed_archive_subgraph_entry_fields,
254 true /* is_closed_archive */, THREAD);
255
256 G1CollectedHeap::heap()->end_archive_alloc_range(closed_archive,
257 os::vm_allocation_granularity());
258 }
259
260 void HeapShared::copy_open_archive_heap_objects(
261 GrowableArray<MemRegion> * open_archive) {
262 assert(is_heap_object_archiving_allowed(), "Cannot archive java heap objects");
263
264 Thread* THREAD = Thread::current();
265 G1CollectedHeap::heap()->begin_archive_alloc_range(true /* open */);
266
267 java_lang_Class::archive_basic_type_mirrors(THREAD);
268
269 archive_klass_objects(THREAD);
270
271 archive_object_subgraphs(open_archive_subgraph_entry_fields,
272 num_open_archive_subgraph_entry_fields,
273 false /* is_closed_archive */,
274 THREAD);
275
276 G1CollectedHeap::heap()->end_archive_alloc_range(open_archive,
277 os::vm_allocation_granularity());
278 }
279
280 void HeapShared::init_narrow_oop_decoding(address base, int shift) {
281 _narrow_oop_base = base;
282 _narrow_oop_shift = shift;
283 }
284
285 //
286 // Subgraph archiving support
287 //
288 HeapShared::DumpTimeKlassSubGraphInfoTable* HeapShared::_dump_time_subgraph_info_table = NULL;
289 HeapShared::RunTimeKlassSubGraphInfoTable HeapShared::_run_time_subgraph_info_table;
290
291 // Get the subgraph_info for Klass k. A new subgraph_info is created if
292 // there is no existing one for k. The subgraph_info records the relocated
293 // Klass* of the original k.
294 KlassSubGraphInfo* HeapShared::get_subgraph_info(Klass* k) {
295 assert(DumpSharedSpaces, "dump time only");
296 Klass* relocated_k = MetaspaceShared::get_relocated_klass(k);
297 KlassSubGraphInfo* info = _dump_time_subgraph_info_table->get(relocated_k);
298 if (info == NULL) {
299 _dump_time_subgraph_info_table->put(relocated_k, KlassSubGraphInfo(relocated_k));
300 info = _dump_time_subgraph_info_table->get(relocated_k);
301 ++ _dump_time_subgraph_info_table->_count;
302 }
303 return info;
304 }
305
306 // Add an entry field to the current KlassSubGraphInfo.
307 void KlassSubGraphInfo::add_subgraph_entry_field(
308 int static_field_offset, oop v, bool is_closed_archive) {
309 assert(DumpSharedSpaces, "dump time only");
310 if (_subgraph_entry_fields == NULL) {
311 _subgraph_entry_fields =
312 new(ResourceObj::C_HEAP, mtClass) GrowableArray<juint>(10, true);
313 }
314 _subgraph_entry_fields->append((juint)static_field_offset);
315 _subgraph_entry_fields->append(CompressedOops::encode(v));
316 _subgraph_entry_fields->append(is_closed_archive ? 1 : 0);
317 }
318
319 // Add the Klass* for an object in the current KlassSubGraphInfo's subgraphs.
320 // Only objects of boot classes can be included in sub-graph.
321 void KlassSubGraphInfo::add_subgraph_object_klass(Klass* orig_k, Klass *relocated_k) {
322 assert(DumpSharedSpaces, "dump time only");
323 assert(relocated_k == MetaspaceShared::get_relocated_klass(orig_k),
324 "must be the relocated Klass in the shared space");
325
326 if (_subgraph_object_klasses == NULL) {
327 _subgraph_object_klasses =
328 new(ResourceObj::C_HEAP, mtClass) GrowableArray<Klass*>(50, true);
329 }
330
331 assert(relocated_k->is_shared(), "must be a shared class");
332
333 if (_k == relocated_k) {
334 // Don't add the Klass containing the sub-graph to it's own klass
335 // initialization list.
336 return;
337 }
338
339 if (relocated_k->is_instance_klass()) {
340 assert(InstanceKlass::cast(relocated_k)->is_shared_boot_class(),
341 "must be boot class");
342 // SystemDictionary::xxx_klass() are not updated, need to check
343 // the original Klass*
344 if (orig_k == SystemDictionary::String_klass() ||
345 orig_k == SystemDictionary::Object_klass()) {
346 // Initialized early during VM initialization. No need to be added
347 // to the sub-graph object class list.
348 return;
349 }
350 } else if (relocated_k->is_objArray_klass()) {
351 Klass* abk = ObjArrayKlass::cast(relocated_k)->bottom_klass();
352 if (abk->is_instance_klass()) {
353 assert(InstanceKlass::cast(abk)->is_shared_boot_class(),
354 "must be boot class");
355 }
356 if (relocated_k == Universe::objectArrayKlassObj()) {
357 // Initialized early during Universe::genesis. No need to be added
358 // to the list.
359 return;
360 }
361 } else {
362 assert(relocated_k->is_typeArray_klass(), "must be");
363 // Primitive type arrays are created early during Universe::genesis.
364 return;
365 }
366
367 if (log_is_enabled(Debug, cds, heap)) {
368 if (!_subgraph_object_klasses->contains(relocated_k)) {
369 ResourceMark rm;
370 log_debug(cds, heap)("Adding klass %s", orig_k->external_name());
371 }
372 }
373
374 _subgraph_object_klasses->append_if_missing(relocated_k);
375 }
376
377 // Initialize an archived subgraph_info_record from the given KlassSubGraphInfo.
378 void ArchivedKlassSubGraphInfoRecord::init(KlassSubGraphInfo* info) {
379 _k = info->klass();
380 _entry_field_records = NULL;
381 _subgraph_object_klasses = NULL;
382
383 // populate the entry fields
384 GrowableArray<juint>* entry_fields = info->subgraph_entry_fields();
385 if (entry_fields != NULL) {
386 int num_entry_fields = entry_fields->length();
387 assert(num_entry_fields % 3 == 0, "sanity");
388 _entry_field_records =
389 MetaspaceShared::new_ro_array<juint>(num_entry_fields);
390 for (int i = 0 ; i < num_entry_fields; i++) {
391 _entry_field_records->at_put(i, entry_fields->at(i));
392 }
393 }
394
395 // the Klasses of the objects in the sub-graphs
396 GrowableArray<Klass*>* subgraph_object_klasses = info->subgraph_object_klasses();
397 if (subgraph_object_klasses != NULL) {
398 int num_subgraphs_klasses = subgraph_object_klasses->length();
399 _subgraph_object_klasses =
400 MetaspaceShared::new_ro_array<Klass*>(num_subgraphs_klasses);
401 for (int i = 0; i < num_subgraphs_klasses; i++) {
402 Klass* subgraph_k = subgraph_object_klasses->at(i);
403 if (log_is_enabled(Info, cds, heap)) {
404 ResourceMark rm;
405 log_info(cds, heap)(
406 "Archived object klass %s (%2d) => %s",
407 _k->external_name(), i, subgraph_k->external_name());
408 }
409 _subgraph_object_klasses->at_put(i, subgraph_k);
410 ArchivePtrMarker::mark_pointer(_subgraph_object_klasses->adr_at(i));
411 }
412 }
413
414 ArchivePtrMarker::mark_pointer(&_k);
415 ArchivePtrMarker::mark_pointer(&_entry_field_records);
416 ArchivePtrMarker::mark_pointer(&_subgraph_object_klasses);
417 }
418
419 struct CopyKlassSubGraphInfoToArchive : StackObj {
420 CompactHashtableWriter* _writer;
421 CopyKlassSubGraphInfoToArchive(CompactHashtableWriter* writer) : _writer(writer) {}
422
423 bool do_entry(Klass* klass, KlassSubGraphInfo& info) {
424 if (info.subgraph_object_klasses() != NULL || info.subgraph_entry_fields() != NULL) {
425 ArchivedKlassSubGraphInfoRecord* record =
426 (ArchivedKlassSubGraphInfoRecord*)MetaspaceShared::read_only_space_alloc(sizeof(ArchivedKlassSubGraphInfoRecord));
427 record->init(&info);
428
429 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary(klass);
430 u4 delta = MetaspaceShared::object_delta_u4(record);
431 _writer->add(hash, delta);
432 }
433 return true; // keep on iterating
434 }
435 };
436
437 // Build the records of archived subgraph infos, which include:
438 // - Entry points to all subgraphs from the containing class mirror. The entry
439 // points are static fields in the mirror. For each entry point, the field
440 // offset, value and is_closed_archive flag are recorded in the sub-graph
441 // info. The value is stored back to the corresponding field at runtime.
442 // - A list of klasses that need to be loaded/initialized before archived
443 // java object sub-graph can be accessed at runtime.
444 void HeapShared::write_subgraph_info_table() {
445 // Allocate the contents of the hashtable(s) inside the RO region of the CDS archive.
446 DumpTimeKlassSubGraphInfoTable* d_table = _dump_time_subgraph_info_table;
447 CompactHashtableStats stats;
448
449 _run_time_subgraph_info_table.reset();
450
451 CompactHashtableWriter writer(d_table->_count, &stats);
452 CopyKlassSubGraphInfoToArchive copy(&writer);
453 d_table->iterate(©);
454
455 writer.dump(&_run_time_subgraph_info_table, "subgraphs");
456 }
457
458 void HeapShared::serialize_subgraph_info_table_header(SerializeClosure* soc) {
459 _run_time_subgraph_info_table.serialize_header(soc);
460 }
461
462 void HeapShared::initialize_from_archived_subgraph(Klass* k) {
463 if (!open_archive_heap_region_mapped()) {
464 return; // nothing to do
465 }
466 assert(!DumpSharedSpaces, "Should not be called with DumpSharedSpaces");
467
468 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary(k);
469 const ArchivedKlassSubGraphInfoRecord* record = _run_time_subgraph_info_table.lookup(k, hash, 0);
470
471 // Initialize from archived data. Currently this is done only
472 // during VM initialization time. No lock is needed.
473 if (record != NULL) {
474 Thread* THREAD = Thread::current();
475
476 int i;
477 // Load/link/initialize the klasses of the objects in the subgraph.
478 // NULL class loader is used.
479 Array<Klass*>* klasses = record->subgraph_object_klasses();
480 if (klasses != NULL) {
481 for (i = 0; i < klasses->length(); i++) {
482 Klass* obj_k = klasses->at(i);
483 Klass* resolved_k = SystemDictionary::resolve_or_null(
484 (obj_k)->name(), THREAD);
485 if (resolved_k != obj_k) {
486 assert(!SystemDictionary::is_well_known_klass(resolved_k),
487 "shared well-known classes must not be replaced by JVMTI ClassFileLoadHook");
488 ResourceMark rm(THREAD);
489 log_info(cds, heap)("Failed to load subgraph because %s was not loaded from archive",
490 resolved_k->external_name());
491 return;
492 }
493 if ((obj_k)->is_instance_klass()) {
494 InstanceKlass* ik = InstanceKlass::cast(obj_k);
495 ik->initialize(THREAD);
496 } else if ((obj_k)->is_objArray_klass()) {
497 ObjArrayKlass* oak = ObjArrayKlass::cast(obj_k);
498 oak->initialize(THREAD);
499 }
500 }
501 }
502
503 if (HAS_PENDING_EXCEPTION) {
504 CLEAR_PENDING_EXCEPTION;
505 // None of the field value will be set if there was an exception.
506 // The java code will not see any of the archived objects in the
507 // subgraphs referenced from k in this case.
508 return;
509 }
510
511 // Load the subgraph entry fields from the record and store them back to
512 // the corresponding fields within the mirror.
513 oop m = k->java_mirror();
514 Array<juint>* entry_field_records = record->entry_field_records();
515 if (entry_field_records != NULL) {
516 int efr_len = entry_field_records->length();
517 assert(efr_len % 3 == 0, "sanity");
518 for (i = 0; i < efr_len;) {
519 int field_offset = entry_field_records->at(i);
520 narrowOop nv = entry_field_records->at(i+1);
521 int is_closed_archive = entry_field_records->at(i+2);
522 oop v;
523 if (is_closed_archive == 0) {
524 // It's an archived object in the open archive heap regions, not shared.
525 // The object refereced by the field becomes 'known' by GC from this
526 // point. All objects in the subgraph reachable from the object are
527 // also 'known' by GC.
528 v = materialize_archived_object(nv);
529 } else {
530 // Shared object in the closed archive heap regions. Decode directly.
531 assert(!CompressedOops::is_null(nv), "shared object is null");
532 v = HeapShared::decode_from_archive(nv);
533 }
534 m->obj_field_put(field_offset, v);
535 i += 3;
536
537 log_debug(cds, heap)(" " PTR_FORMAT " init field @ %2d = " PTR_FORMAT, p2i(k), field_offset, p2i(v));
538 }
539
540 // Done. Java code can see the archived sub-graphs referenced from k's
541 // mirror after this point.
542 if (log_is_enabled(Info, cds, heap)) {
543 ResourceMark rm;
544 log_info(cds, heap)("initialize_from_archived_subgraph %s " PTR_FORMAT,
545 k->external_name(), p2i(k));
546 }
547 }
548 }
549 }
550
551 class WalkOopAndArchiveClosure: public BasicOopIterateClosure {
552 int _level;
553 bool _is_closed_archive;
554 bool _record_klasses_only;
555 KlassSubGraphInfo* _subgraph_info;
556 oop _orig_referencing_obj;
557 oop _archived_referencing_obj;
558 Thread* _thread;
559 public:
560 WalkOopAndArchiveClosure(int level,
561 bool is_closed_archive,
562 bool record_klasses_only,
563 KlassSubGraphInfo* subgraph_info,
564 oop orig, oop archived, TRAPS) :
565 _level(level), _is_closed_archive(is_closed_archive),
566 _record_klasses_only(record_klasses_only),
567 _subgraph_info(subgraph_info),
568 _orig_referencing_obj(orig), _archived_referencing_obj(archived),
569 _thread(THREAD) {}
570 void do_oop(narrowOop *p) { WalkOopAndArchiveClosure::do_oop_work(p); }
571 void do_oop( oop *p) { WalkOopAndArchiveClosure::do_oop_work(p); }
572
573 protected:
574 template <class T> void do_oop_work(T *p) {
575 oop obj = RawAccess<>::oop_load(p);
576 if (!CompressedOops::is_null(obj)) {
577 assert(!HeapShared::is_archived_object(obj),
578 "original objects must not point to archived objects");
579
580 size_t field_delta = pointer_delta(p, _orig_referencing_obj, sizeof(char));
581 T* new_p = (T*)(cast_from_oop<address>(_archived_referencing_obj) + field_delta);
582 Thread* THREAD = _thread;
583
584 if (!_record_klasses_only && log_is_enabled(Debug, cds, heap)) {
585 ResourceMark rm;
586 log_debug(cds, heap)("(%d) %s[" SIZE_FORMAT "] ==> " PTR_FORMAT " size %d %s", _level,
587 _orig_referencing_obj->klass()->external_name(), field_delta,
588 p2i(obj), obj->size() * HeapWordSize, obj->klass()->external_name());
589 LogTarget(Trace, cds, heap) log;
590 LogStream out(log);
591 obj->print_on(&out);
592 }
593
594 oop archived = HeapShared::archive_reachable_objects_from(
595 _level + 1, _subgraph_info, obj, _is_closed_archive, THREAD);
596 assert(archived != NULL, "VM should have exited with unarchivable objects for _level > 1");
597 assert(HeapShared::is_archived_object(archived), "must be");
598
599 if (!_record_klasses_only) {
600 // Update the reference in the archived copy of the referencing object.
601 log_debug(cds, heap)("(%d) updating oop @[" PTR_FORMAT "] " PTR_FORMAT " ==> " PTR_FORMAT,
602 _level, p2i(new_p), p2i(obj), p2i(archived));
603 RawAccess<IS_NOT_NULL>::oop_store(new_p, archived);
604 }
605 }
606 }
607 };
608
609 void HeapShared::check_closed_archive_heap_region_object(InstanceKlass* k,
610 Thread* THREAD) {
611 // Check fields in the object
612 for (JavaFieldStream fs(k); !fs.done(); fs.next()) {
613 if (!fs.access_flags().is_static()) {
614 BasicType ft = fs.field_descriptor().field_type();
615 if (!fs.access_flags().is_final() && is_reference_type(ft)) {
616 ResourceMark rm(THREAD);
617 log_warning(cds, heap)(
618 "Please check reference field in %s instance in closed archive heap region: %s %s",
619 k->external_name(), (fs.name())->as_C_string(),
620 (fs.signature())->as_C_string());
621 }
622 }
623 }
624 }
625
626 // (1) If orig_obj has not been archived yet, archive it.
627 // (2) If orig_obj has not been seen yet (since start_recording_subgraph() was called),
628 // trace all objects that are reachable from it, and make sure these objects are archived.
629 // (3) Record the klasses of all orig_obj and all reachable objects.
630 oop HeapShared::archive_reachable_objects_from(int level,
631 KlassSubGraphInfo* subgraph_info,
632 oop orig_obj,
633 bool is_closed_archive,
634 TRAPS) {
635 assert(orig_obj != NULL, "must be");
636 assert(!is_archived_object(orig_obj), "sanity");
637
638 if (!JavaClasses::is_supported_for_archiving(orig_obj)) {
639 // This object has injected fields that cannot be supported easily, so we disallow them for now.
640 // If you get an error here, you probably made a change in the JDK library that has added
641 // these objects that are referenced (directly or indirectly) by static fields.
642 ResourceMark rm;
643 log_error(cds, heap)("Cannot archive object of class %s", orig_obj->klass()->external_name());
644 vm_exit(1);
645 }
646
647 // java.lang.Class instances cannot be included in an archived object sub-graph. We only support
648 // them as Klass::_archived_mirror because they need to be specially restored at run time.
649 //
650 // If you get an error here, you probably made a change in the JDK library that has added a Class
651 // object that is referenced (directly or indirectly) by static fields.
652 if (java_lang_Class::is_instance(orig_obj)) {
653 log_error(cds, heap)("(%d) Unknown java.lang.Class object is in the archived sub-graph", level);
654 vm_exit(1);
655 }
656
657 oop archived_obj = find_archived_heap_object(orig_obj);
658 if (java_lang_String::is_instance(orig_obj) && archived_obj != NULL) {
659 // To save time, don't walk strings that are already archived. They just contain
660 // pointers to a type array, whose klass doesn't need to be recorded.
661 return archived_obj;
662 }
663
664 if (has_been_seen_during_subgraph_recording(orig_obj)) {
665 // orig_obj has already been archived and traced. Nothing more to do.
666 return archived_obj;
667 } else {
668 set_has_been_seen_during_subgraph_recording(orig_obj);
669 }
670
671 bool record_klasses_only = (archived_obj != NULL);
672 if (archived_obj == NULL) {
673 ++_num_new_archived_objs;
674 archived_obj = archive_heap_object(orig_obj, THREAD);
675 if (archived_obj == NULL) {
676 // Skip archiving the sub-graph referenced from the current entry field.
677 ResourceMark rm;
678 log_error(cds, heap)(
679 "Cannot archive the sub-graph referenced from %s object ("
680 PTR_FORMAT ") size %d, skipped.",
681 orig_obj->klass()->external_name(), p2i(orig_obj), orig_obj->size() * HeapWordSize);
682 if (level == 1) {
683 // Don't archive a subgraph root that's too big. For archives static fields, that's OK
684 // as the Java code will take care of initializing this field dynamically.
685 return NULL;
686 } else {
687 // We don't know how to handle an object that has been archived, but some of its reachable
688 // objects cannot be archived. Bail out for now. We might need to fix this in the future if
689 // we have a real use case.
690 vm_exit(1);
691 }
692 }
693 }
694
695 assert(archived_obj != NULL, "must be");
696 Klass *orig_k = orig_obj->klass();
697 Klass *relocated_k = archived_obj->klass();
698 subgraph_info->add_subgraph_object_klass(orig_k, relocated_k);
699
700 WalkOopAndArchiveClosure walker(level, is_closed_archive, record_klasses_only,
701 subgraph_info, orig_obj, archived_obj, THREAD);
702 orig_obj->oop_iterate(&walker);
703 if (is_closed_archive && orig_k->is_instance_klass()) {
704 check_closed_archive_heap_region_object(InstanceKlass::cast(orig_k), THREAD);
705 }
706 return archived_obj;
707 }
708
709 //
710 // Start from the given static field in a java mirror and archive the
711 // complete sub-graph of java heap objects that are reached directly
712 // or indirectly from the starting object by following references.
713 // Sub-graph archiving restrictions (current):
714 //
715 // - All classes of objects in the archived sub-graph (including the
716 // entry class) must be boot class only.
717 // - No java.lang.Class instance (java mirror) can be included inside
718 // an archived sub-graph. Mirror can only be the sub-graph entry object.
719 //
720 // The Java heap object sub-graph archiving process (see
721 // WalkOopAndArchiveClosure):
722 //
723 // 1) Java object sub-graph archiving starts from a given static field
724 // within a Class instance (java mirror). If the static field is a
725 // refererence field and points to a non-null java object, proceed to
726 // the next step.
727 //
728 // 2) Archives the referenced java object. If an archived copy of the
729 // current object already exists, updates the pointer in the archived
730 // copy of the referencing object to point to the current archived object.
731 // Otherwise, proceed to the next step.
732 //
733 // 3) Follows all references within the current java object and recursively
734 // archive the sub-graph of objects starting from each reference.
735 //
736 // 4) Updates the pointer in the archived copy of referencing object to
737 // point to the current archived object.
738 //
739 // 5) The Klass of the current java object is added to the list of Klasses
740 // for loading and initialzing before any object in the archived graph can
741 // be accessed at runtime.
742 //
743 void HeapShared::archive_reachable_objects_from_static_field(InstanceKlass *k,
744 const char* klass_name,
745 int field_offset,
746 const char* field_name,
747 bool is_closed_archive,
748 TRAPS) {
749 assert(DumpSharedSpaces, "dump time only");
750 assert(k->is_shared_boot_class(), "must be boot class");
751
752 oop m = k->java_mirror();
753
754 KlassSubGraphInfo* subgraph_info = get_subgraph_info(k);
755 oop f = m->obj_field(field_offset);
756
757 log_debug(cds, heap)("Start archiving from: %s::%s (" PTR_FORMAT ")", klass_name, field_name, p2i(f));
758
759 if (!CompressedOops::is_null(f)) {
760 if (log_is_enabled(Trace, cds, heap)) {
761 LogTarget(Trace, cds, heap) log;
762 LogStream out(log);
763 f->print_on(&out);
764 }
765
766 oop af = archive_reachable_objects_from(1, subgraph_info, f,
767 is_closed_archive, CHECK);
768
769 if (af == NULL) {
770 log_error(cds, heap)("Archiving failed %s::%s (some reachable objects cannot be archived)",
771 klass_name, field_name);
772 } else {
773 // Note: the field value is not preserved in the archived mirror.
774 // Record the field as a new subGraph entry point. The recorded
775 // information is restored from the archive at runtime.
776 subgraph_info->add_subgraph_entry_field(field_offset, af, is_closed_archive);
777 log_info(cds, heap)("Archived field %s::%s => " PTR_FORMAT, klass_name, field_name, p2i(af));
778 }
779 } else {
780 // The field contains null, we still need to record the entry point,
781 // so it can be restored at runtime.
782 subgraph_info->add_subgraph_entry_field(field_offset, NULL, false);
783 }
784 }
785
786 #ifndef PRODUCT
787 class VerifySharedOopClosure: public BasicOopIterateClosure {
788 private:
789 bool _is_archived;
790
791 public:
792 VerifySharedOopClosure(bool is_archived) : _is_archived(is_archived) {}
793
794 void do_oop(narrowOop *p) { VerifySharedOopClosure::do_oop_work(p); }
795 void do_oop( oop *p) { VerifySharedOopClosure::do_oop_work(p); }
796
797 protected:
798 template <class T> void do_oop_work(T *p) {
799 oop obj = RawAccess<>::oop_load(p);
800 if (!CompressedOops::is_null(obj)) {
801 HeapShared::verify_reachable_objects_from(obj, _is_archived);
802 }
803 }
804 };
805
806 void HeapShared::verify_subgraph_from_static_field(InstanceKlass* k, int field_offset) {
807 assert(DumpSharedSpaces, "dump time only");
808 assert(k->is_shared_boot_class(), "must be boot class");
809
810 oop m = k->java_mirror();
811 oop f = m->obj_field(field_offset);
812 if (!CompressedOops::is_null(f)) {
813 verify_subgraph_from(f);
814 }
815 }
816
817 void HeapShared::verify_subgraph_from(oop orig_obj) {
818 oop archived_obj = find_archived_heap_object(orig_obj);
819 if (archived_obj == NULL) {
820 // It's OK for the root of a subgraph to be not archived. See comments in
821 // archive_reachable_objects_from().
822 return;
823 }
824
825 // Verify that all objects reachable from orig_obj are archived.
826 init_seen_objects_table();
827 verify_reachable_objects_from(orig_obj, false);
828 delete_seen_objects_table();
829
830 // Note: we could also verify that all objects reachable from the archived
831 // copy of orig_obj can only point to archived objects, with:
832 // init_seen_objects_table();
833 // verify_reachable_objects_from(archived_obj, true);
834 // init_seen_objects_table();
835 // but that's already done in G1HeapVerifier::verify_archive_regions so we
836 // won't do it here.
837 }
838
839 void HeapShared::verify_reachable_objects_from(oop obj, bool is_archived) {
840 _num_total_verifications ++;
841 if (!has_been_seen_during_subgraph_recording(obj)) {
842 set_has_been_seen_during_subgraph_recording(obj);
843
844 if (is_archived) {
845 assert(is_archived_object(obj), "must be");
846 assert(find_archived_heap_object(obj) == NULL, "must be");
847 } else {
848 assert(!is_archived_object(obj), "must be");
849 assert(find_archived_heap_object(obj) != NULL, "must be");
850 }
851
852 VerifySharedOopClosure walker(is_archived);
853 obj->oop_iterate(&walker);
854 }
855 }
856 #endif
857
858 HeapShared::SeenObjectsTable* HeapShared::_seen_objects_table = NULL;
859 int HeapShared::_num_new_walked_objs;
860 int HeapShared::_num_new_archived_objs;
861 int HeapShared::_num_old_recorded_klasses;
862
863 int HeapShared::_num_total_subgraph_recordings = 0;
864 int HeapShared::_num_total_walked_objs = 0;
865 int HeapShared::_num_total_archived_objs = 0;
866 int HeapShared::_num_total_recorded_klasses = 0;
867 int HeapShared::_num_total_verifications = 0;
868
869 bool HeapShared::has_been_seen_during_subgraph_recording(oop obj) {
870 return _seen_objects_table->get(obj) != NULL;
871 }
872
873 void HeapShared::set_has_been_seen_during_subgraph_recording(oop obj) {
874 assert(!has_been_seen_during_subgraph_recording(obj), "sanity");
875 _seen_objects_table->put(obj, true);
876 ++ _num_new_walked_objs;
877 }
878
879 void HeapShared::start_recording_subgraph(InstanceKlass *k, const char* class_name) {
880 log_info(cds, heap)("Start recording subgraph(s) for archived fields in %s", class_name);
881 init_seen_objects_table();
882 _num_new_walked_objs = 0;
883 _num_new_archived_objs = 0;
884 _num_old_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses();
885 }
886
887 void HeapShared::done_recording_subgraph(InstanceKlass *k, const char* class_name) {
888 int num_new_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses() -
889 _num_old_recorded_klasses;
890 log_info(cds, heap)("Done recording subgraph(s) for archived fields in %s: "
891 "walked %d objs, archived %d new objs, recorded %d classes",
892 class_name, _num_new_walked_objs, _num_new_archived_objs,
893 num_new_recorded_klasses);
894
895 delete_seen_objects_table();
896
897 _num_total_subgraph_recordings ++;
898 _num_total_walked_objs += _num_new_walked_objs;
899 _num_total_archived_objs += _num_new_archived_objs;
900 _num_total_recorded_klasses += num_new_recorded_klasses;
901 }
902
903 class ArchivableStaticFieldFinder: public FieldClosure {
904 InstanceKlass* _ik;
905 Symbol* _field_name;
906 bool _found;
907 int _offset;
908 public:
909 ArchivableStaticFieldFinder(InstanceKlass* ik, Symbol* field_name) :
910 _ik(ik), _field_name(field_name), _found(false), _offset(-1) {}
911
912 virtual void do_field(fieldDescriptor* fd) {
913 if (fd->name() == _field_name) {
914 assert(!_found, "fields cannot be overloaded");
915 assert(is_reference_type(fd->field_type()), "can archive only fields that are references");
916 _found = true;
917 _offset = fd->offset();
918 }
919 }
920 bool found() { return _found; }
921 int offset() { return _offset; }
922 };
923
924 void HeapShared::init_subgraph_entry_fields(ArchivableStaticFieldInfo fields[],
925 int num, Thread* THREAD) {
926 for (int i = 0; i < num; i++) {
927 ArchivableStaticFieldInfo* info = &fields[i];
928 TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name);
929 TempNewSymbol field_name = SymbolTable::new_symbol(info->field_name);
930
931 Klass* k = SystemDictionary::resolve_or_null(klass_name, THREAD);
932 assert(k != NULL && !HAS_PENDING_EXCEPTION, "class must exist");
933 InstanceKlass* ik = InstanceKlass::cast(k);
934 assert(InstanceKlass::cast(ik)->is_shared_boot_class(),
935 "Only support boot classes");
936 ik->initialize(THREAD);
937 guarantee(!HAS_PENDING_EXCEPTION, "exception in initialize");
938
939 ArchivableStaticFieldFinder finder(ik, field_name);
940 ik->do_local_static_fields(&finder);
941 assert(finder.found(), "field must exist");
942
943 info->klass = ik;
944 info->offset = finder.offset();
945 }
946 }
947
948 void HeapShared::init_subgraph_entry_fields(Thread* THREAD) {
949 _dump_time_subgraph_info_table = new (ResourceObj::C_HEAP, mtClass)DumpTimeKlassSubGraphInfoTable();
950
951 init_subgraph_entry_fields(closed_archive_subgraph_entry_fields,
952 num_closed_archive_subgraph_entry_fields,
953 THREAD);
954 init_subgraph_entry_fields(open_archive_subgraph_entry_fields,
955 num_open_archive_subgraph_entry_fields,
956 THREAD);
957 }
958
959 void HeapShared::archive_object_subgraphs(ArchivableStaticFieldInfo fields[],
960 int num, bool is_closed_archive,
961 Thread* THREAD) {
962 _num_total_subgraph_recordings = 0;
963 _num_total_walked_objs = 0;
964 _num_total_archived_objs = 0;
965 _num_total_recorded_klasses = 0;
966 _num_total_verifications = 0;
967
968 // For each class X that has one or more archived fields:
969 // [1] Dump the subgraph of each archived field
970 // [2] Create a list of all the class of the objects that can be reached
971 // by any of these static fields.
972 // At runtime, these classes are initialized before X's archived fields
973 // are restored by HeapShared::initialize_from_archived_subgraph().
974 int i;
975 for (i = 0; i < num; ) {
976 ArchivableStaticFieldInfo* info = &fields[i];
977 const char* klass_name = info->klass_name;
978 start_recording_subgraph(info->klass, klass_name);
979
980 // If you have specified consecutive fields of the same klass in
981 // fields[], these will be archived in the same
982 // {start_recording_subgraph ... done_recording_subgraph} pass to
983 // save time.
984 for (; i < num; i++) {
985 ArchivableStaticFieldInfo* f = &fields[i];
986 if (f->klass_name != klass_name) {
987 break;
988 }
989 archive_reachable_objects_from_static_field(f->klass, f->klass_name,
990 f->offset, f->field_name,
991 is_closed_archive, CHECK);
992 }
993 done_recording_subgraph(info->klass, klass_name);
994 }
995
996 log_info(cds, heap)("Archived subgraph records in %s archive heap region = %d",
997 is_closed_archive ? "closed" : "open",
998 _num_total_subgraph_recordings);
999 log_info(cds, heap)(" Walked %d objects", _num_total_walked_objs);
1000 log_info(cds, heap)(" Archived %d objects", _num_total_archived_objs);
1001 log_info(cds, heap)(" Recorded %d klasses", _num_total_recorded_klasses);
1002
1003 #ifndef PRODUCT
1004 for (int i = 0; i < num; i++) {
1005 ArchivableStaticFieldInfo* f = &fields[i];
1006 verify_subgraph_from_static_field(f->klass, f->offset);
1007 }
1008 log_info(cds, heap)(" Verified %d references", _num_total_verifications);
1009 #endif
1010 }
1011
1012 // At dump-time, find the location of all the non-null oop pointers in an archived heap
1013 // region. This way we can quickly relocate all the pointers without using
1014 // BasicOopIterateClosure at runtime.
1015 class FindEmbeddedNonNullPointers: public BasicOopIterateClosure {
1016 narrowOop* _start;
1017 BitMap *_oopmap;
1018 int _num_total_oops;
1019 int _num_null_oops;
1020 public:
1021 FindEmbeddedNonNullPointers(narrowOop* start, BitMap* oopmap)
1022 : _start(start), _oopmap(oopmap), _num_total_oops(0), _num_null_oops(0) {}
1023
1024 virtual bool should_verify_oops(void) {
1025 return false;
1026 }
1027 virtual void do_oop(narrowOop* p) {
1028 _num_total_oops ++;
1029 narrowOop v = *p;
1030 if (!CompressedOops::is_null(v)) {
1031 size_t idx = p - _start;
1032 _oopmap->set_bit(idx);
1033 } else {
1034 _num_null_oops ++;
1035 }
1036 }
1037 virtual void do_oop(oop *p) {
1038 ShouldNotReachHere();
1039 }
1040 int num_total_oops() const { return _num_total_oops; }
1041 int num_null_oops() const { return _num_null_oops; }
1042 };
1043
1044 ResourceBitMap HeapShared::calculate_oopmap(MemRegion region) {
1045 assert(UseCompressedOops, "must be");
1046 size_t num_bits = region.byte_size() / sizeof(narrowOop);
1047 ResourceBitMap oopmap(num_bits);
1048
1049 HeapWord* p = region.start();
1050 HeapWord* end = region.end();
1051 FindEmbeddedNonNullPointers finder((narrowOop*)p, &oopmap);
1052
1053 int num_objs = 0;
1054 while (p < end) {
1055 oop o = (oop)p;
1056 o->oop_iterate(&finder);
1057 p += o->size();
1058 ++ num_objs;
1059 }
1060
1061 log_info(cds, heap)("calculate_oopmap: objects = %6d, embedded oops = %7d, nulls = %7d",
1062 num_objs, finder.num_total_oops(), finder.num_null_oops());
1063 return oopmap;
1064 }
1065
1066 // Patch all the embedded oop pointers inside an archived heap region,
1067 // to be consistent with the runtime oop encoding.
1068 class PatchEmbeddedPointers: public BitMapClosure {
1069 narrowOop* _start;
1070
1071 public:
1072 PatchEmbeddedPointers(narrowOop* start) : _start(start) {}
1073
1074 bool do_bit(size_t offset) {
1075 narrowOop* p = _start + offset;
1076 narrowOop v = *p;
1077 assert(!CompressedOops::is_null(v), "null oops should have been filtered out at dump time");
1078 oop o = HeapShared::decode_from_archive(v);
1079 RawAccess<IS_NOT_NULL>::oop_store(p, o);
1080 return true;
1081 }
1082 };
1083
1084 void HeapShared::patch_archived_heap_embedded_pointers(MemRegion region, address oopmap,
1085 size_t oopmap_size_in_bits) {
1086 BitMapView bm((BitMap::bm_word_t*)oopmap, oopmap_size_in_bits);
1087
1088 #ifndef PRODUCT
1089 ResourceMark rm;
1090 ResourceBitMap checkBm = calculate_oopmap(region);
1091 assert(bm.is_same(checkBm), "sanity");
1092 #endif
1093
1094 PatchEmbeddedPointers patcher((narrowOop*)region.start());
1095 bm.iterate(&patcher);
1096 }
1097
1098 #endif // INCLUDE_CDS_JAVA_HEAP