1 /*
2 * Copyright (c) 2018, 2019, 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 "memory/universe.hpp"
40 #include "oops/compressedOops.inline.hpp"
41 #include "oops/fieldStreams.hpp"
42 #include "oops/oop.inline.hpp"
43 #include "runtime/fieldDescriptor.inline.hpp"
44 #include "runtime/safepointVerifiers.hpp"
45 #include "utilities/bitMap.inline.hpp"
46 #if INCLUDE_G1GC
47 #include "gc/g1/g1CollectedHeap.hpp"
48 #endif
49
50 #if INCLUDE_CDS_JAVA_HEAP
51
52 bool HeapShared::_closed_archive_heap_region_mapped = false;
53 bool HeapShared::_open_archive_heap_region_mapped = false;
54 bool HeapShared::_archive_heap_region_fixed = false;
55
56 address HeapShared::_narrow_oop_base;
57 int HeapShared::_narrow_oop_shift;
58
59 //
60 // If you add new entries to the following tables, you should know what you're doing!
61 //
62
63 // Entry fields for shareable subgraphs archived in the closed archive heap
64 // region. Warning: Objects in the subgraphs should not have reference fields
65 // assigned at runtime.
66 static ArchivableStaticFieldInfo closed_archive_subgraph_entry_fields[] = {
67 {"java/lang/Integer$IntegerCache", "archivedCache"},
68 {"java/lang/Long$LongCache", "archivedCache"},
69 {"java/lang/Byte$ByteCache", "archivedCache"},
70 {"java/lang/Short$ShortCache", "archivedCache"},
71 {"java/lang/Character$CharacterCache", "archivedCache"},
72 {"java/util/jar/Attributes$Name", "KNOWN_NAMES"},
73 {"sun/util/locale/BaseLocale", "constantBaseLocales"},
74 };
75 // Entry fields for subgraphs archived in the open archive heap region.
76 static ArchivableStaticFieldInfo open_archive_subgraph_entry_fields[] = {
77 {"jdk/internal/module/ArchivedModuleGraph", "archivedModuleGraph"},
78 {"java/util/ImmutableCollections$ListN", "EMPTY_LIST"},
79 {"java/util/ImmutableCollections$MapN", "EMPTY_MAP"},
80 {"java/util/ImmutableCollections$SetN", "EMPTY_SET"},
81 {"java/lang/module/Configuration", "EMPTY_CONFIGURATION"},
82 {"jdk/internal/math/FDBigInteger", "archivedCaches"},
83 {"java/math/BigInteger", "archivedCaches"},
84 };
85
86 const static int num_closed_archive_subgraph_entry_fields =
87 sizeof(closed_archive_subgraph_entry_fields) / sizeof(ArchivableStaticFieldInfo);
88 const static int num_open_archive_subgraph_entry_fields =
89 sizeof(open_archive_subgraph_entry_fields) / sizeof(ArchivableStaticFieldInfo);
90
91 ////////////////////////////////////////////////////////////////
92 //
93 // Java heap object archiving support
94 //
95 ////////////////////////////////////////////////////////////////
96 void HeapShared::fixup_mapped_heap_regions() {
97 FileMapInfo *mapinfo = FileMapInfo::current_info();
98 mapinfo->fixup_mapped_heap_regions();
99 set_archive_heap_region_fixed();
100 }
101
102 unsigned HeapShared::oop_hash(oop const& p) {
103 assert(!p->mark()->has_bias_pattern(),
104 "this object should never have been locked"); // so identity_hash won't safepoin
105 unsigned hash = (unsigned)p->identity_hash();
106 return hash;
107 }
108
109 HeapShared::ArchivedObjectCache* HeapShared::_archived_object_cache = NULL;
110 oop HeapShared::find_archived_heap_object(oop obj) {
111 assert(DumpSharedSpaces, "dump-time only");
112 ArchivedObjectCache* cache = archived_object_cache();
113 oop* p = cache->get(obj);
114 if (p != NULL) {
115 return *p;
116 } else {
117 return NULL;
118 }
119 }
120
121 oop HeapShared::archive_heap_object(oop obj, Thread* THREAD) {
122 assert(DumpSharedSpaces, "dump-time only");
123
124 oop ao = find_archived_heap_object(obj);
125 if (ao != NULL) {
126 // already archived
127 return ao;
128 }
129
130 int len = obj->size();
131 if (G1CollectedHeap::heap()->is_archive_alloc_too_large(len)) {
132 log_debug(cds, heap)("Cannot archive, object (" PTR_FORMAT ") is too large: " SIZE_FORMAT,
133 p2i(obj), (size_t)obj->size());
134 return NULL;
135 }
136
137 // Pre-compute object identity hash at CDS dump time.
138 obj->identity_hash();
139
140 oop archived_oop = (oop)G1CollectedHeap::heap()->archive_mem_allocate(len);
141 if (archived_oop != NULL) {
142 Copy::aligned_disjoint_words((HeapWord*)obj, (HeapWord*)archived_oop, len);
143 MetaspaceShared::relocate_klass_ptr(archived_oop);
144 ArchivedObjectCache* cache = archived_object_cache();
145 cache->put(obj, archived_oop);
146 log_debug(cds, heap)("Archived heap object " PTR_FORMAT " ==> " PTR_FORMAT,
147 p2i(obj), p2i(archived_oop));
148 } else {
149 log_error(cds, heap)(
150 "Cannot allocate space for object " PTR_FORMAT " in archived heap region",
151 p2i(obj));
152 vm_exit(1);
153 }
154 return archived_oop;
155 }
156
157 oop HeapShared::materialize_archived_object(narrowOop v) {
158 assert(archive_heap_region_fixed(),
159 "must be called after archive heap regions are fixed");
160 if (!CompressedOops::is_null(v)) {
161 oop obj = HeapShared::decode_from_archive(v);
162 return G1CollectedHeap::heap()->materialize_archived_object(obj);
163 }
164 return NULL;
165 }
166
167 void HeapShared::archive_klass_objects(Thread* THREAD) {
168 GrowableArray<Klass*>* klasses = MetaspaceShared::collected_klasses();
169 assert(klasses != NULL, "sanity");
170 for (int i = 0; i < klasses->length(); i++) {
171 Klass* k = klasses->at(i);
172
173 // archive mirror object
174 java_lang_Class::archive_mirror(k, CHECK);
175
176 // archive the resolved_referenes array
177 if (k->is_instance_klass()) {
178 InstanceKlass* ik = InstanceKlass::cast(k);
179 ik->constants()->archive_resolved_references(THREAD);
180 }
181 }
182 }
183
184 void HeapShared::archive_java_heap_objects(GrowableArray<MemRegion> *closed,
185 GrowableArray<MemRegion> *open) {
186 if (!is_heap_object_archiving_allowed()) {
187 if (log_is_enabled(Info, cds)) {
188 log_info(cds)(
189 "Archived java heap is not supported as UseG1GC, "
190 "UseCompressedOops and UseCompressedClassPointers are required."
191 "Current settings: UseG1GC=%s, UseCompressedOops=%s, UseCompressedClassPointers=%s.",
192 BOOL_TO_STR(UseG1GC), BOOL_TO_STR(UseCompressedOops),
193 BOOL_TO_STR(UseCompressedClassPointers));
194 }
195 return;
196 }
197
198 G1HeapVerifier::verify_ready_for_archiving();
199
200 {
201 NoSafepointVerifier nsv;
202
203 // Cache for recording where the archived objects are copied to
204 create_archived_object_cache();
205
206 tty->print_cr("Dumping objects to closed archive heap region ...");
207 NOT_PRODUCT(StringTable::verify());
208 copy_closed_archive_heap_objects(closed);
209
210 tty->print_cr("Dumping objects to open archive heap region ...");
211 copy_open_archive_heap_objects(open);
212
213 destroy_archived_object_cache();
214 }
215
216 G1HeapVerifier::verify_archive_regions();
217 }
218
219 void HeapShared::copy_closed_archive_heap_objects(
220 GrowableArray<MemRegion> * closed_archive) {
221 assert(is_heap_object_archiving_allowed(), "Cannot archive java heap objects");
222
223 Thread* THREAD = Thread::current();
224 G1CollectedHeap::heap()->begin_archive_alloc_range();
225
226 // Archive interned string objects
227 StringTable::write_to_archive();
228
229 archive_object_subgraphs(closed_archive_subgraph_entry_fields,
230 num_closed_archive_subgraph_entry_fields,
231 true /* is_closed_archive */, THREAD);
232
233 G1CollectedHeap::heap()->end_archive_alloc_range(closed_archive,
234 os::vm_allocation_granularity());
235 }
236
237 void HeapShared::copy_open_archive_heap_objects(
238 GrowableArray<MemRegion> * open_archive) {
239 assert(is_heap_object_archiving_allowed(), "Cannot archive java heap objects");
240
241 Thread* THREAD = Thread::current();
242 G1CollectedHeap::heap()->begin_archive_alloc_range(true /* open */);
243
244 java_lang_Class::archive_basic_type_mirrors(THREAD);
245
246 archive_klass_objects(THREAD);
247
248 archive_object_subgraphs(open_archive_subgraph_entry_fields,
249 num_open_archive_subgraph_entry_fields,
250 false /* is_closed_archive */,
251 THREAD);
252
253 G1CollectedHeap::heap()->end_archive_alloc_range(open_archive,
254 os::vm_allocation_granularity());
255 }
256
257 void HeapShared::init_narrow_oop_decoding(address base, int shift) {
258 _narrow_oop_base = base;
259 _narrow_oop_shift = shift;
260 }
261
262 //
263 // Subgraph archiving support
264 //
265 HeapShared::DumpTimeKlassSubGraphInfoTable* HeapShared::_dump_time_subgraph_info_table = NULL;
266 HeapShared::RunTimeKlassSubGraphInfoTable HeapShared::_run_time_subgraph_info_table;
267
268 // Get the subgraph_info for Klass k. A new subgraph_info is created if
269 // there is no existing one for k. The subgraph_info records the relocated
270 // Klass* of the original k.
271 KlassSubGraphInfo* HeapShared::get_subgraph_info(Klass* k) {
272 assert(DumpSharedSpaces, "dump time only");
273 Klass* relocated_k = MetaspaceShared::get_relocated_klass(k);
274 KlassSubGraphInfo* info = _dump_time_subgraph_info_table->get(relocated_k);
275 if (info == NULL) {
276 _dump_time_subgraph_info_table->put(relocated_k, KlassSubGraphInfo(relocated_k));
277 info = _dump_time_subgraph_info_table->get(relocated_k);
278 ++ _dump_time_subgraph_info_table->_count;
279 }
280 return info;
281 }
282
283 // Add an entry field to the current KlassSubGraphInfo.
284 void KlassSubGraphInfo::add_subgraph_entry_field(
285 int static_field_offset, oop v, bool is_closed_archive) {
286 assert(DumpSharedSpaces, "dump time only");
287 if (_subgraph_entry_fields == NULL) {
288 _subgraph_entry_fields =
289 new(ResourceObj::C_HEAP, mtClass) GrowableArray<juint>(10, true);
290 }
291 _subgraph_entry_fields->append((juint)static_field_offset);
292 _subgraph_entry_fields->append(CompressedOops::encode(v));
293 _subgraph_entry_fields->append(is_closed_archive ? 1 : 0);
294 }
295
296 // Add the Klass* for an object in the current KlassSubGraphInfo's subgraphs.
297 // Only objects of boot classes can be included in sub-graph.
298 void KlassSubGraphInfo::add_subgraph_object_klass(Klass* orig_k, Klass *relocated_k) {
299 assert(DumpSharedSpaces, "dump time only");
300 assert(relocated_k == MetaspaceShared::get_relocated_klass(orig_k),
301 "must be the relocated Klass in the shared space");
302
303 if (_subgraph_object_klasses == NULL) {
304 _subgraph_object_klasses =
305 new(ResourceObj::C_HEAP, mtClass) GrowableArray<Klass*>(50, true);
306 }
307
308 assert(relocated_k->is_shared(), "must be a shared class");
309
310 if (_k == relocated_k) {
311 // Don't add the Klass containing the sub-graph to it's own klass
312 // initialization list.
313 return;
314 }
315
316 if (relocated_k->is_instance_klass()) {
317 assert(InstanceKlass::cast(relocated_k)->is_shared_boot_class(),
318 "must be boot class");
319 // SystemDictionary::xxx_klass() are not updated, need to check
320 // the original Klass*
321 if (orig_k == SystemDictionary::String_klass() ||
322 orig_k == SystemDictionary::Object_klass()) {
323 // Initialized early during VM initialization. No need to be added
324 // to the sub-graph object class list.
325 return;
326 }
327 } else if (relocated_k->is_objArray_klass()) {
328 Klass* abk = ObjArrayKlass::cast(relocated_k)->bottom_klass();
329 if (abk->is_instance_klass()) {
330 assert(InstanceKlass::cast(abk)->is_shared_boot_class(),
331 "must be boot class");
332 }
333 if (relocated_k == Universe::objectArrayKlassObj()) {
334 // Initialized early during Universe::genesis. No need to be added
335 // to the list.
336 return;
337 }
338 } else {
339 assert(relocated_k->is_typeArray_klass(), "must be");
340 // Primitive type arrays are created early during Universe::genesis.
341 return;
342 }
343
344 if (log_is_enabled(Debug, cds, heap)) {
345 if (!_subgraph_object_klasses->contains(relocated_k)) {
346 ResourceMark rm;
347 log_debug(cds, heap)("Adding klass %s", orig_k->external_name());
348 }
349 }
350
351 _subgraph_object_klasses->append_if_missing(relocated_k);
352 }
353
354 // Initialize an archived subgraph_info_record from the given KlassSubGraphInfo.
355 void ArchivedKlassSubGraphInfoRecord::init(KlassSubGraphInfo* info) {
356 _k = info->klass();
357 _entry_field_records = NULL;
358 _subgraph_object_klasses = NULL;
359
360 // populate the entry fields
361 GrowableArray<juint>* entry_fields = info->subgraph_entry_fields();
362 if (entry_fields != NULL) {
363 int num_entry_fields = entry_fields->length();
364 assert(num_entry_fields % 3 == 0, "sanity");
365 _entry_field_records =
366 MetaspaceShared::new_ro_array<juint>(num_entry_fields);
367 for (int i = 0 ; i < num_entry_fields; i++) {
368 _entry_field_records->at_put(i, entry_fields->at(i));
369 }
370 }
371
372 // the Klasses of the objects in the sub-graphs
373 GrowableArray<Klass*>* subgraph_object_klasses = info->subgraph_object_klasses();
374 if (subgraph_object_klasses != NULL) {
375 int num_subgraphs_klasses = subgraph_object_klasses->length();
376 _subgraph_object_klasses =
377 MetaspaceShared::new_ro_array<Klass*>(num_subgraphs_klasses);
378 for (int i = 0; i < num_subgraphs_klasses; i++) {
379 Klass* subgraph_k = subgraph_object_klasses->at(i);
380 if (log_is_enabled(Info, cds, heap)) {
381 ResourceMark rm;
382 log_info(cds, heap)(
383 "Archived object klass %s (%2d) => %s",
384 _k->external_name(), i, subgraph_k->external_name());
385 }
386 _subgraph_object_klasses->at_put(i, subgraph_k);
387 }
388 }
389 }
390
391 struct CopyKlassSubGraphInfoToArchive : StackObj {
392 CompactHashtableWriter* _writer;
393 CopyKlassSubGraphInfoToArchive(CompactHashtableWriter* writer) : _writer(writer) {}
394
395 bool do_entry(Klass* klass, KlassSubGraphInfo& info) {
396 if (info.subgraph_object_klasses() != NULL || info.subgraph_entry_fields() != NULL) {
397 ArchivedKlassSubGraphInfoRecord* record =
398 (ArchivedKlassSubGraphInfoRecord*)MetaspaceShared::read_only_space_alloc(sizeof(ArchivedKlassSubGraphInfoRecord));
399 record->init(&info);
400
401 unsigned int hash = primitive_hash<Klass*>(klass);
402 u4 delta = MetaspaceShared::object_delta_u4(record);
403 _writer->add(hash, delta);
404 }
405 return true; // keep on iterating
406 }
407 };
408
409 // Build the records of archived subgraph infos, which include:
410 // - Entry points to all subgraphs from the containing class mirror. The entry
411 // points are static fields in the mirror. For each entry point, the field
412 // offset, value and is_closed_archive flag are recorded in the sub-graph
413 // info. The value is stored back to the corresponding field at runtime.
414 // - A list of klasses that need to be loaded/initialized before archived
415 // java object sub-graph can be accessed at runtime.
416 void HeapShared::write_subgraph_info_table() {
417 // Allocate the contents of the hashtable(s) inside the RO region of the CDS archive.
418 DumpTimeKlassSubGraphInfoTable* d_table = _dump_time_subgraph_info_table;
419 CompactHashtableStats stats;
420
421 _run_time_subgraph_info_table.reset();
422
423 CompactHashtableWriter writer(d_table->_count, &stats);
424 CopyKlassSubGraphInfoToArchive copy(&writer);
425 d_table->iterate(©);
426
427 writer.dump(&_run_time_subgraph_info_table, "subgraphs");
428 }
429
430 void HeapShared::serialize_subgraph_info_table_header(SerializeClosure* soc) {
431 _run_time_subgraph_info_table.serialize_header(soc);
432 }
433
434 void HeapShared::initialize_from_archived_subgraph(Klass* k) {
435 if (!open_archive_heap_region_mapped()) {
436 return; // nothing to do
437 }
438 assert(!DumpSharedSpaces, "Should not be called with DumpSharedSpaces");
439
440 unsigned int hash = primitive_hash<Klass*>(k);
441 const ArchivedKlassSubGraphInfoRecord* record = _run_time_subgraph_info_table.lookup(k, hash, 0);
442
443 // Initialize from archived data. Currently this is done only
444 // during VM initialization time. No lock is needed.
445 if (record != NULL) {
446 Thread* THREAD = Thread::current();
447
448 int i;
449 // Load/link/initialize the klasses of the objects in the subgraph.
450 // NULL class loader is used.
451 Array<Klass*>* klasses = record->subgraph_object_klasses();
452 if (klasses != NULL) {
453 for (i = 0; i < klasses->length(); i++) {
454 Klass* obj_k = klasses->at(i);
455 Klass* resolved_k = SystemDictionary::resolve_or_null(
456 (obj_k)->name(), THREAD);
457 if (resolved_k != obj_k) {
458 assert(!SystemDictionary::is_well_known_klass(resolved_k),
459 "shared well-known classes must not be replaced by JVMTI ClassFileLoadHook");
460 ResourceMark rm(THREAD);
461 log_info(cds, heap)("Failed to load subgraph because %s was not loaded from archive",
462 resolved_k->external_name());
463 return;
464 }
465 if ((obj_k)->is_instance_klass()) {
466 InstanceKlass* ik = InstanceKlass::cast(obj_k);
467 ik->initialize(THREAD);
468 } else if ((obj_k)->is_objArray_klass()) {
469 ObjArrayKlass* oak = ObjArrayKlass::cast(obj_k);
470 oak->initialize(THREAD);
471 }
472 }
473 }
474
475 if (HAS_PENDING_EXCEPTION) {
476 CLEAR_PENDING_EXCEPTION;
477 // None of the field value will be set if there was an exception.
478 // The java code will not see any of the archived objects in the
479 // subgraphs referenced from k in this case.
480 return;
481 }
482
483 // Load the subgraph entry fields from the record and store them back to
484 // the corresponding fields within the mirror.
485 oop m = k->java_mirror();
486 Array<juint>* entry_field_records = record->entry_field_records();
487 if (entry_field_records != NULL) {
488 int efr_len = entry_field_records->length();
489 assert(efr_len % 3 == 0, "sanity");
490 for (i = 0; i < efr_len;) {
491 int field_offset = entry_field_records->at(i);
492 narrowOop nv = entry_field_records->at(i+1);
493 int is_closed_archive = entry_field_records->at(i+2);
494 oop v;
495 if (is_closed_archive == 0) {
496 // It's an archived object in the open archive heap regions, not shared.
497 // The object refereced by the field becomes 'known' by GC from this
498 // point. All objects in the subgraph reachable from the object are
499 // also 'known' by GC.
500 v = materialize_archived_object(nv);
501 } else {
502 // Shared object in the closed archive heap regions. Decode directly.
503 assert(!CompressedOops::is_null(nv), "shared object is null");
504 v = HeapShared::decode_from_archive(nv);
505 }
506 m->obj_field_put(field_offset, v);
507 i += 3;
508
509 log_debug(cds, heap)(" " PTR_FORMAT " init field @ %2d = " PTR_FORMAT, p2i(k), field_offset, p2i(v));
510 }
511
512 // Done. Java code can see the archived sub-graphs referenced from k's
513 // mirror after this point.
514 if (log_is_enabled(Info, cds, heap)) {
515 ResourceMark rm;
516 log_info(cds, heap)("initialize_from_archived_subgraph %s " PTR_FORMAT,
517 k->external_name(), p2i(k));
518 }
519 }
520 }
521 }
522
523 class WalkOopAndArchiveClosure: public BasicOopIterateClosure {
524 int _level;
525 bool _is_closed_archive;
526 bool _record_klasses_only;
527 KlassSubGraphInfo* _subgraph_info;
528 oop _orig_referencing_obj;
529 oop _archived_referencing_obj;
530 Thread* _thread;
531 public:
532 WalkOopAndArchiveClosure(int level,
533 bool is_closed_archive,
534 bool record_klasses_only,
535 KlassSubGraphInfo* subgraph_info,
536 oop orig, oop archived, TRAPS) :
537 _level(level), _is_closed_archive(is_closed_archive),
538 _record_klasses_only(record_klasses_only),
539 _subgraph_info(subgraph_info),
540 _orig_referencing_obj(orig), _archived_referencing_obj(archived),
541 _thread(THREAD) {}
542 void do_oop(narrowOop *p) { WalkOopAndArchiveClosure::do_oop_work(p); }
543 void do_oop( oop *p) { WalkOopAndArchiveClosure::do_oop_work(p); }
544
545 protected:
546 template <class T> void do_oop_work(T *p) {
547 oop obj = RawAccess<>::oop_load(p);
548 if (!CompressedOops::is_null(obj)) {
549 assert(!HeapShared::is_archived_object(obj),
550 "original objects must not point to archived objects");
551
552 size_t field_delta = pointer_delta(p, _orig_referencing_obj, sizeof(char));
553 T* new_p = (T*)(address(_archived_referencing_obj) + field_delta);
554 Thread* THREAD = _thread;
555
556 if (!_record_klasses_only && log_is_enabled(Debug, cds, heap)) {
557 ResourceMark rm;
558 log_debug(cds, heap)("(%d) %s[" SIZE_FORMAT "] ==> " PTR_FORMAT " size %d %s", _level,
559 _orig_referencing_obj->klass()->external_name(), field_delta,
560 p2i(obj), obj->size() * HeapWordSize, obj->klass()->external_name());
561 LogTarget(Trace, cds, heap) log;
562 LogStream out(log);
563 obj->print_on(&out);
564 }
565
566 oop archived = HeapShared::archive_reachable_objects_from(
567 _level + 1, _subgraph_info, obj, _is_closed_archive, THREAD);
568 assert(archived != NULL, "VM should have exited with unarchivable objects for _level > 1");
569 assert(HeapShared::is_archived_object(archived), "must be");
570
571 if (!_record_klasses_only) {
572 // Update the reference in the archived copy of the referencing object.
573 log_debug(cds, heap)("(%d) updating oop @[" PTR_FORMAT "] " PTR_FORMAT " ==> " PTR_FORMAT,
574 _level, p2i(new_p), p2i(obj), p2i(archived));
575 RawAccess<IS_NOT_NULL>::oop_store(new_p, archived);
576 }
577 }
578 }
579 };
580
581 void HeapShared::check_closed_archive_heap_region_object(InstanceKlass* k,
582 Thread* THREAD) {
583 // Check fields in the object
584 for (JavaFieldStream fs(k); !fs.done(); fs.next()) {
585 if (!fs.access_flags().is_static()) {
586 BasicType ft = fs.field_descriptor().field_type();
587 if (!fs.access_flags().is_final() && (ft == T_ARRAY || ft == T_OBJECT)) {
588 ResourceMark rm(THREAD);
589 log_warning(cds, heap)(
590 "Please check reference field in %s instance in closed archive heap region: %s %s",
591 k->external_name(), (fs.name())->as_C_string(),
592 (fs.signature())->as_C_string());
593 }
594 }
595 }
596 }
597
598 // (1) If orig_obj has not been archived yet, archive it.
599 // (2) If orig_obj has not been seen yet (since start_recording_subgraph() was called),
600 // trace all objects that are reachable from it, and make sure these objects are archived.
601 // (3) Record the klasses of all orig_obj and all reachable objects.
602 oop HeapShared::archive_reachable_objects_from(int level,
603 KlassSubGraphInfo* subgraph_info,
604 oop orig_obj,
605 bool is_closed_archive,
606 TRAPS) {
607 assert(orig_obj != NULL, "must be");
608 assert(!is_archived_object(orig_obj), "sanity");
609
610 // java.lang.Class instances cannot be included in an archived
611 // object sub-graph.
612 if (java_lang_Class::is_instance(orig_obj)) {
613 log_error(cds, heap)("(%d) Unknown java.lang.Class object is in the archived sub-graph", level);
614 vm_exit(1);
615 }
616
617 oop archived_obj = find_archived_heap_object(orig_obj);
618 if (java_lang_String::is_instance(orig_obj) && archived_obj != NULL) {
619 // To save time, don't walk strings that are already archived. They just contain
620 // pointers to a type array, whose klass doesn't need to be recorded.
621 return archived_obj;
622 }
623
624 if (has_been_seen_during_subgraph_recording(orig_obj)) {
625 // orig_obj has already been archived and traced. Nothing more to do.
626 return archived_obj;
627 } else {
628 set_has_been_seen_during_subgraph_recording(orig_obj);
629 }
630
631 bool record_klasses_only = (archived_obj != NULL);
632 if (archived_obj == NULL) {
633 ++_num_new_archived_objs;
634 archived_obj = archive_heap_object(orig_obj, THREAD);
635 if (archived_obj == NULL) {
636 // Skip archiving the sub-graph referenced from the current entry field.
637 ResourceMark rm;
638 log_error(cds, heap)(
639 "Cannot archive the sub-graph referenced from %s object ("
640 PTR_FORMAT ") size %d, skipped.",
641 orig_obj->klass()->external_name(), p2i(orig_obj), orig_obj->size() * HeapWordSize);
642 if (level == 1) {
643 // Don't archive a subgraph root that's too big. For archives static fields, that's OK
644 // as the Java code will take care of initializing this field dynamically.
645 return NULL;
646 } else {
647 // We don't know how to handle an object that has been archived, but some of its reachable
648 // objects cannot be archived. Bail out for now. We might need to fix this in the future if
649 // we have a real use case.
650 vm_exit(1);
651 }
652 }
653 }
654
655 assert(archived_obj != NULL, "must be");
656 Klass *orig_k = orig_obj->klass();
657 Klass *relocated_k = archived_obj->klass();
658 subgraph_info->add_subgraph_object_klass(orig_k, relocated_k);
659
660 WalkOopAndArchiveClosure walker(level, is_closed_archive, record_klasses_only,
661 subgraph_info, orig_obj, archived_obj, THREAD);
662 orig_obj->oop_iterate(&walker);
663 if (is_closed_archive && orig_k->is_instance_klass()) {
664 check_closed_archive_heap_region_object(InstanceKlass::cast(orig_k), THREAD);
665 }
666 return archived_obj;
667 }
668
669 //
670 // Start from the given static field in a java mirror and archive the
671 // complete sub-graph of java heap objects that are reached directly
672 // or indirectly from the starting object by following references.
673 // Sub-graph archiving restrictions (current):
674 //
675 // - All classes of objects in the archived sub-graph (including the
676 // entry class) must be boot class only.
677 // - No java.lang.Class instance (java mirror) can be included inside
678 // an archived sub-graph. Mirror can only be the sub-graph entry object.
679 //
680 // The Java heap object sub-graph archiving process (see
681 // WalkOopAndArchiveClosure):
682 //
683 // 1) Java object sub-graph archiving starts from a given static field
684 // within a Class instance (java mirror). If the static field is a
685 // refererence field and points to a non-null java object, proceed to
686 // the next step.
687 //
688 // 2) Archives the referenced java object. If an archived copy of the
689 // current object already exists, updates the pointer in the archived
690 // copy of the referencing object to point to the current archived object.
691 // Otherwise, proceed to the next step.
692 //
693 // 3) Follows all references within the current java object and recursively
694 // archive the sub-graph of objects starting from each reference.
695 //
696 // 4) Updates the pointer in the archived copy of referencing object to
697 // point to the current archived object.
698 //
699 // 5) The Klass of the current java object is added to the list of Klasses
700 // for loading and initialzing before any object in the archived graph can
701 // be accessed at runtime.
702 //
703 void HeapShared::archive_reachable_objects_from_static_field(InstanceKlass *k,
704 const char* klass_name,
705 int field_offset,
706 const char* field_name,
707 bool is_closed_archive,
708 TRAPS) {
709 assert(DumpSharedSpaces, "dump time only");
710 assert(k->is_shared_boot_class(), "must be boot class");
711
712 oop m = k->java_mirror();
713
714 KlassSubGraphInfo* subgraph_info = get_subgraph_info(k);
715 oop f = m->obj_field(field_offset);
716
717 log_debug(cds, heap)("Start archiving from: %s::%s (" PTR_FORMAT ")", klass_name, field_name, p2i(f));
718
719 if (!CompressedOops::is_null(f)) {
720 if (log_is_enabled(Trace, cds, heap)) {
721 LogTarget(Trace, cds, heap) log;
722 LogStream out(log);
723 f->print_on(&out);
724 }
725
726 oop af = archive_reachable_objects_from(1, subgraph_info, f,
727 is_closed_archive, CHECK);
728
729 if (af == NULL) {
730 log_error(cds, heap)("Archiving failed %s::%s (some reachable objects cannot be archived)",
731 klass_name, field_name);
732 } else {
733 // Note: the field value is not preserved in the archived mirror.
734 // Record the field as a new subGraph entry point. The recorded
735 // information is restored from the archive at runtime.
736 subgraph_info->add_subgraph_entry_field(field_offset, af, is_closed_archive);
737 log_info(cds, heap)("Archived field %s::%s => " PTR_FORMAT, klass_name, field_name, p2i(af));
738 }
739 } else {
740 // The field contains null, we still need to record the entry point,
741 // so it can be restored at runtime.
742 subgraph_info->add_subgraph_entry_field(field_offset, NULL, false);
743 }
744 }
745
746 #ifndef PRODUCT
747 class VerifySharedOopClosure: public BasicOopIterateClosure {
748 private:
749 bool _is_archived;
750
751 public:
752 VerifySharedOopClosure(bool is_archived) : _is_archived(is_archived) {}
753
754 void do_oop(narrowOop *p) { VerifySharedOopClosure::do_oop_work(p); }
755 void do_oop( oop *p) { VerifySharedOopClosure::do_oop_work(p); }
756
757 protected:
758 template <class T> void do_oop_work(T *p) {
759 oop obj = RawAccess<>::oop_load(p);
760 if (!CompressedOops::is_null(obj)) {
761 HeapShared::verify_reachable_objects_from(obj, _is_archived);
762 }
763 }
764 };
765
766 void HeapShared::verify_subgraph_from_static_field(InstanceKlass* k, int field_offset) {
767 assert(DumpSharedSpaces, "dump time only");
768 assert(k->is_shared_boot_class(), "must be boot class");
769
770 oop m = k->java_mirror();
771 oop f = m->obj_field(field_offset);
772 if (!CompressedOops::is_null(f)) {
773 verify_subgraph_from(f);
774 }
775 }
776
777 void HeapShared::verify_subgraph_from(oop orig_obj) {
778 oop archived_obj = find_archived_heap_object(orig_obj);
779 if (archived_obj == NULL) {
780 // It's OK for the root of a subgraph to be not archived. See comments in
781 // archive_reachable_objects_from().
782 return;
783 }
784
785 // Verify that all objects reachable from orig_obj are archived.
786 init_seen_objects_table();
787 verify_reachable_objects_from(orig_obj, false);
788 delete_seen_objects_table();
789
790 // Note: we could also verify that all objects reachable from the archived
791 // copy of orig_obj can only point to archived objects, with:
792 // init_seen_objects_table();
793 // verify_reachable_objects_from(archived_obj, true);
794 // init_seen_objects_table();
795 // but that's already done in G1HeapVerifier::verify_archive_regions so we
796 // won't do it here.
797 }
798
799 void HeapShared::verify_reachable_objects_from(oop obj, bool is_archived) {
800 _num_total_verifications ++;
801 if (!has_been_seen_during_subgraph_recording(obj)) {
802 set_has_been_seen_during_subgraph_recording(obj);
803
804 if (is_archived) {
805 assert(is_archived_object(obj), "must be");
806 assert(find_archived_heap_object(obj) == NULL, "must be");
807 } else {
808 assert(!is_archived_object(obj), "must be");
809 assert(find_archived_heap_object(obj) != NULL, "must be");
810 }
811
812 VerifySharedOopClosure walker(is_archived);
813 obj->oop_iterate(&walker);
814 }
815 }
816 #endif
817
818 HeapShared::SeenObjectsTable* HeapShared::_seen_objects_table = NULL;
819 int HeapShared::_num_new_walked_objs;
820 int HeapShared::_num_new_archived_objs;
821 int HeapShared::_num_old_recorded_klasses;
822
823 int HeapShared::_num_total_subgraph_recordings = 0;
824 int HeapShared::_num_total_walked_objs = 0;
825 int HeapShared::_num_total_archived_objs = 0;
826 int HeapShared::_num_total_recorded_klasses = 0;
827 int HeapShared::_num_total_verifications = 0;
828
829 bool HeapShared::has_been_seen_during_subgraph_recording(oop obj) {
830 return _seen_objects_table->get(obj) != NULL;
831 }
832
833 void HeapShared::set_has_been_seen_during_subgraph_recording(oop obj) {
834 assert(!has_been_seen_during_subgraph_recording(obj), "sanity");
835 _seen_objects_table->put(obj, true);
836 ++ _num_new_walked_objs;
837 }
838
839 void HeapShared::start_recording_subgraph(InstanceKlass *k, const char* class_name) {
840 log_info(cds, heap)("Start recording subgraph(s) for archived fields in %s", class_name);
841 init_seen_objects_table();
842 _num_new_walked_objs = 0;
843 _num_new_archived_objs = 0;
844 _num_old_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses();
845 }
846
847 void HeapShared::done_recording_subgraph(InstanceKlass *k, const char* class_name) {
848 int num_new_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses() -
849 _num_old_recorded_klasses;
850 log_info(cds, heap)("Done recording subgraph(s) for archived fields in %s: "
851 "walked %d objs, archived %d new objs, recorded %d classes",
852 class_name, _num_new_walked_objs, _num_new_archived_objs,
853 num_new_recorded_klasses);
854
855 delete_seen_objects_table();
856
857 _num_total_subgraph_recordings ++;
858 _num_total_walked_objs += _num_new_walked_objs;
859 _num_total_archived_objs += _num_new_archived_objs;
860 _num_total_recorded_klasses += num_new_recorded_klasses;
861 }
862
863 class ArchivableStaticFieldFinder: public FieldClosure {
864 InstanceKlass* _ik;
865 Symbol* _field_name;
866 bool _found;
867 int _offset;
868 public:
869 ArchivableStaticFieldFinder(InstanceKlass* ik, Symbol* field_name) :
870 _ik(ik), _field_name(field_name), _found(false), _offset(-1) {}
871
872 virtual void do_field(fieldDescriptor* fd) {
873 if (fd->name() == _field_name) {
874 assert(!_found, "fields cannot be overloaded");
875 assert(fd->field_type() == T_OBJECT || fd->field_type() == T_ARRAY, "can archive only obj or array fields");
876 _found = true;
877 _offset = fd->offset();
878 }
879 }
880 bool found() { return _found; }
881 int offset() { return _offset; }
882 };
883
884 void HeapShared::init_subgraph_entry_fields(ArchivableStaticFieldInfo fields[],
885 int num, Thread* THREAD) {
886 for (int i = 0; i < num; i++) {
887 ArchivableStaticFieldInfo* info = &fields[i];
888 TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name);
889 TempNewSymbol field_name = SymbolTable::new_symbol(info->field_name);
890
891 Klass* k = SystemDictionary::resolve_or_null(klass_name, THREAD);
892 assert(k != NULL && !HAS_PENDING_EXCEPTION, "class must exist");
893 InstanceKlass* ik = InstanceKlass::cast(k);
894 assert(InstanceKlass::cast(ik)->is_shared_boot_class(),
895 "Only support boot classes");
896 ik->initialize(THREAD);
897 guarantee(!HAS_PENDING_EXCEPTION, "exception in initialize");
898
899 ArchivableStaticFieldFinder finder(ik, field_name);
900 ik->do_local_static_fields(&finder);
901 assert(finder.found(), "field must exist");
902
903 info->klass = ik;
904 info->offset = finder.offset();
905 }
906 }
907
908 void HeapShared::init_subgraph_entry_fields(Thread* THREAD) {
909 _dump_time_subgraph_info_table = new (ResourceObj::C_HEAP, mtClass)DumpTimeKlassSubGraphInfoTable();
910
911 init_subgraph_entry_fields(closed_archive_subgraph_entry_fields,
912 num_closed_archive_subgraph_entry_fields,
913 THREAD);
914 init_subgraph_entry_fields(open_archive_subgraph_entry_fields,
915 num_open_archive_subgraph_entry_fields,
916 THREAD);
917 }
918
919 void HeapShared::archive_object_subgraphs(ArchivableStaticFieldInfo fields[],
920 int num, bool is_closed_archive,
921 Thread* THREAD) {
922 _num_total_subgraph_recordings = 0;
923 _num_total_walked_objs = 0;
924 _num_total_archived_objs = 0;
925 _num_total_recorded_klasses = 0;
926 _num_total_verifications = 0;
927
928 // For each class X that has one or more archived fields:
929 // [1] Dump the subgraph of each archived field
930 // [2] Create a list of all the class of the objects that can be reached
931 // by any of these static fields.
932 // At runtime, these classes are initialized before X's archived fields
933 // are restored by HeapShared::initialize_from_archived_subgraph().
934 int i;
935 for (i = 0; i < num; ) {
936 ArchivableStaticFieldInfo* info = &fields[i];
937 const char* klass_name = info->klass_name;
938 start_recording_subgraph(info->klass, klass_name);
939
940 // If you have specified consecutive fields of the same klass in
941 // fields[], these will be archived in the same
942 // {start_recording_subgraph ... done_recording_subgraph} pass to
943 // save time.
944 for (; i < num; i++) {
945 ArchivableStaticFieldInfo* f = &fields[i];
946 if (f->klass_name != klass_name) {
947 break;
948 }
949 archive_reachable_objects_from_static_field(f->klass, f->klass_name,
950 f->offset, f->field_name,
951 is_closed_archive, CHECK);
952 }
953 done_recording_subgraph(info->klass, klass_name);
954 }
955
956 log_info(cds, heap)("Archived subgraph records in %s archive heap region = %d",
957 is_closed_archive ? "closed" : "open",
958 _num_total_subgraph_recordings);
959 log_info(cds, heap)(" Walked %d objects", _num_total_walked_objs);
960 log_info(cds, heap)(" Archived %d objects", _num_total_archived_objs);
961 log_info(cds, heap)(" Recorded %d klasses", _num_total_recorded_klasses);
962
963 #ifndef PRODUCT
964 for (int i = 0; i < num; i++) {
965 ArchivableStaticFieldInfo* f = &fields[i];
966 verify_subgraph_from_static_field(f->klass, f->offset);
967 }
968 log_info(cds, heap)(" Verified %d references", _num_total_verifications);
969 #endif
970 }
971
972 // At dump-time, find the location of all the non-null oop pointers in an archived heap
973 // region. This way we can quickly relocate all the pointers without using
974 // BasicOopIterateClosure at runtime.
975 class FindEmbeddedNonNullPointers: public BasicOopIterateClosure {
976 narrowOop* _start;
977 BitMap *_oopmap;
978 int _num_total_oops;
979 int _num_null_oops;
980 public:
981 FindEmbeddedNonNullPointers(narrowOop* start, BitMap* oopmap)
982 : _start(start), _oopmap(oopmap), _num_total_oops(0), _num_null_oops(0) {}
983
984 virtual bool should_verify_oops(void) {
985 return false;
986 }
987 virtual void do_oop(narrowOop* p) {
988 _num_total_oops ++;
989 narrowOop v = *p;
990 if (!CompressedOops::is_null(v)) {
991 size_t idx = p - _start;
992 _oopmap->set_bit(idx);
993 } else {
994 _num_null_oops ++;
995 }
996 }
997 virtual void do_oop(oop *p) {
998 ShouldNotReachHere();
999 }
1000 int num_total_oops() const { return _num_total_oops; }
1001 int num_null_oops() const { return _num_null_oops; }
1002 };
1003
1004 ResourceBitMap HeapShared::calculate_oopmap(MemRegion region) {
1005 assert(UseCompressedOops, "must be");
1006 size_t num_bits = region.byte_size() / sizeof(narrowOop);
1007 ResourceBitMap oopmap(num_bits);
1008
1009 HeapWord* p = region.start();
1010 HeapWord* end = region.end();
1011 FindEmbeddedNonNullPointers finder((narrowOop*)p, &oopmap);
1012
1013 int num_objs = 0;
1014 while (p < end) {
1015 oop o = (oop)p;
1016 o->oop_iterate(&finder);
1017 p += o->size();
1018 ++ num_objs;
1019 }
1020
1021 log_info(cds, heap)("calculate_oopmap: objects = %6d, embedded oops = %7d, nulls = %7d",
1022 num_objs, finder.num_total_oops(), finder.num_null_oops());
1023 return oopmap;
1024 }
1025
1026 // Patch all the embedded oop pointers inside an archived heap region,
1027 // to be consistent with the runtime oop encoding.
1028 class PatchEmbeddedPointers: public BitMapClosure {
1029 narrowOop* _start;
1030
1031 public:
1032 PatchEmbeddedPointers(narrowOop* start) : _start(start) {}
1033
1034 bool do_bit(size_t offset) {
1035 narrowOop* p = _start + offset;
1036 narrowOop v = *p;
1037 assert(!CompressedOops::is_null(v), "null oops should have been filtered out at dump time");
1038 oop o = HeapShared::decode_from_archive(v);
1039 RawAccess<IS_NOT_NULL>::oop_store(p, o);
1040 return true;
1041 }
1042 };
1043
1044 void HeapShared::patch_archived_heap_embedded_pointers(MemRegion region, address oopmap,
1045 size_t oopmap_size_in_bits) {
1046 BitMapView bm((BitMap::bm_word_t*)oopmap, oopmap_size_in_bits);
1047
1048 #ifndef PRODUCT
1049 ResourceMark rm;
1050 ResourceBitMap checkBm = calculate_oopmap(region);
1051 assert(bm.is_same(checkBm), "sanity");
1052 #endif
1053
1054 PatchEmbeddedPointers patcher((narrowOop*)region.start());
1055 bm.iterate(&patcher);
1056 }
1057
1058 #endif // INCLUDE_CDS_JAVA_HEAP