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