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