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/symbolTable.hpp"
28 #include "classfile/vmSymbols.hpp"
29 #include "logging/log.hpp"
30 #include "logging/logMessage.hpp"
31 #include "logging/logStream.hpp"
32 #include "memory/heapShared.inline.hpp"
33 #include "memory/iterator.inline.hpp"
34 #include "memory/metadataFactory.hpp"
35 #include "memory/metaspaceClosure.hpp"
36 #include "memory/metaspaceShared.hpp"
37 #include "memory/resourceArea.hpp"
38 #include "oops/compressedOops.inline.hpp"
39 #include "oops/oop.inline.hpp"
40 #include "runtime/fieldDescriptor.inline.hpp"
41 #include "utilities/bitMap.inline.hpp"
42
43 #if INCLUDE_CDS_JAVA_HEAP
44 KlassSubGraphInfo* HeapShared::_subgraph_info_list = NULL;
45 int HeapShared::_num_archived_subgraph_info_records = 0;
46 Array<ArchivedKlassSubGraphInfoRecord>* HeapShared::_archived_subgraph_info_records = NULL;
47
48 // Currently there is only one class mirror (ArchivedModuleGraph) with archived
49 // sub-graphs.
50 KlassSubGraphInfo* HeapShared::find_subgraph_info(Klass* k) {
51 KlassSubGraphInfo* info = _subgraph_info_list;
52 while (info != NULL) {
53 if (info->klass() == k) {
54 return info;
55 }
56 info = info->next();
57 }
58 return NULL;
59 }
60
61 // Get the subgraph_info for Klass k. A new subgraph_info is created if
62 // there is no existing one for k. The subgraph_info records the relocated
63 // Klass* of the original k.
64 KlassSubGraphInfo* HeapShared::get_subgraph_info(Klass* k) {
65 Klass* relocated_k = MetaspaceShared::get_relocated_klass(k);
66 KlassSubGraphInfo* info = find_subgraph_info(relocated_k);
67 if (info != NULL) {
68 return info;
69 }
70
71 info = new KlassSubGraphInfo(relocated_k, _subgraph_info_list);
72 _subgraph_info_list = info;
73 return info;
74 }
75
76 address HeapShared::_narrow_oop_base;
77 int HeapShared::_narrow_oop_shift;
78
79 int HeapShared::num_of_subgraph_infos() {
80 int num = 0;
81 KlassSubGraphInfo* info = _subgraph_info_list;
82 while (info != NULL) {
83 num ++;
84 info = info->next();
85 }
86 return num;
87 }
88
89 // Add an entry field to the current KlassSubGraphInfo.
90 void KlassSubGraphInfo::add_subgraph_entry_field(int static_field_offset, oop v) {
91 assert(DumpSharedSpaces, "dump time only");
92 if (_subgraph_entry_fields == NULL) {
93 _subgraph_entry_fields =
94 new(ResourceObj::C_HEAP, mtClass) GrowableArray<juint>(10, true);
95 }
96 _subgraph_entry_fields->append((juint)static_field_offset);
97 _subgraph_entry_fields->append(CompressedOops::encode(v));
98 }
99
100 // Add the Klass* for an object in the current KlassSubGraphInfo's subgraphs.
101 // Only objects of boot classes can be included in sub-graph.
102 void KlassSubGraphInfo::add_subgraph_klass(Klass* orig_k, Klass *relocated_k) {
103 assert(DumpSharedSpaces, "dump time only");
104 assert(relocated_k == MetaspaceShared::get_relocated_klass(orig_k),
105 "must be the relocated Klass in the shared space");
106
107 if (_subgraph_klasses == NULL) {
108 _subgraph_klasses =
109 new(ResourceObj::C_HEAP, mtClass) GrowableArray<Klass*>(50, true);
110 }
111
112 assert(relocated_k->is_shared(), "must be a shared class");
113
114 if (_k == relocated_k) {
115 // Don't add the Klass containing the sub-graph to it's own klass
116 // initialization list.
117 return;
118 }
119
120 if (relocated_k->is_instance_klass()) {
121 assert(InstanceKlass::cast(relocated_k)->is_shared_boot_class(),
122 "must be boot class");
123 // SystemDictionary::xxx_klass() are not updated, need to check
124 // the original Klass*
125 if (orig_k == SystemDictionary::String_klass() ||
126 orig_k == SystemDictionary::Object_klass()) {
127 // Initialized early during VM initialization. No need to be added
128 // to the sub-graph object class list.
129 return;
130 }
131 } else if (relocated_k->is_objArray_klass()) {
132 Klass* abk = ObjArrayKlass::cast(relocated_k)->bottom_klass();
133 if (abk->is_instance_klass()) {
134 assert(InstanceKlass::cast(abk)->is_shared_boot_class(),
135 "must be boot class");
136 }
137 if (relocated_k == Universe::objectArrayKlassObj()) {
138 // Initialized early during Universe::genesis. No need to be added
139 // to the list.
140 return;
141 }
142 } else {
143 assert(relocated_k->is_typeArray_klass(), "must be");
144 // Primitive type arrays are created early during Universe::genesis.
145 return;
146 }
147
148 if (log_is_enabled(Debug, cds, heap)) {
149 if (!_subgraph_klasses->contains(relocated_k)) {
150 ResourceMark rm;
151 log_debug(cds, heap)("Adding klass %s", orig_k->external_name());
152 }
153 }
154
155 _subgraph_klasses->append_if_missing(relocated_k);
156 }
157
158 // Initialize an archived subgraph_info_record from the given KlassSubGraphInfo.
159 void ArchivedKlassSubGraphInfoRecord::init(KlassSubGraphInfo* info) {
160 _k = info->klass();
161 _next = NULL;
162 _entry_field_records = NULL;
163 _subgraph_klasses = NULL;
164
165 // populate the entry fields
166 GrowableArray<juint>* entry_fields = info->subgraph_entry_fields();
167 if (entry_fields != NULL) {
168 int num_entry_fields = entry_fields->length();
169 assert(num_entry_fields % 2 == 0, "sanity");
170 _entry_field_records =
171 MetaspaceShared::new_ro_array<juint>(num_entry_fields);
172 for (int i = 0 ; i < num_entry_fields; i++) {
173 _entry_field_records->at_put(i, entry_fields->at(i));
174 }
175 }
176
177 // the Klasses of the objects in the sub-graphs
178 GrowableArray<Klass*>* subgraph_klasses = info->subgraph_klasses();
179 if (subgraph_klasses != NULL) {
180 int num_subgraphs_klasses = subgraph_klasses->length();
181 _subgraph_klasses =
182 MetaspaceShared::new_ro_array<Klass*>(num_subgraphs_klasses);
183 for (int i = 0; i < num_subgraphs_klasses; i++) {
184 Klass* subgraph_k = subgraph_klasses->at(i);
185 if (log_is_enabled(Info, cds, heap)) {
186 ResourceMark rm;
187 log_info(cds, heap)(
188 "Archived object klass %s (%2d) => %s",
189 _k->external_name(), i, subgraph_k->external_name());
190 }
191 _subgraph_klasses->at_put(i, subgraph_k);
192 }
193 }
194 }
195
196 // Build the records of archived subgraph infos, which include:
197 // - Entry points to all subgraphs from the containing class mirror. The entry
198 // points are static fields in the mirror. For each entry point, the field
199 // offset and value are recorded in the sub-graph info. The value are stored
200 // back to the corresponding field at runtime.
201 // - A list of klasses that need to be loaded/initialized before archived
202 // java object sub-graph can be accessed at runtime.
203 //
204 // The records are saved in the archive file and reloaded at runtime. Currently
205 // there is only one class mirror (ArchivedModuleGraph) with archived sub-graphs.
206 //
207 // Layout of the archived subgraph info records:
208 //
209 // records_size | num_records | records*
210 // ArchivedKlassSubGraphInfoRecord | entry_fields | subgraph_klasses
211 size_t HeapShared::build_archived_subgraph_info_records(int num_records) {
212 // remember the start address
213 char* start_p = MetaspaceShared::read_only_space_top();
214
215 // now populate the archived subgraph infos, which will be saved in the
216 // archive file
217 _archived_subgraph_info_records =
218 MetaspaceShared::new_ro_array<ArchivedKlassSubGraphInfoRecord>(num_records);
219 KlassSubGraphInfo* info = _subgraph_info_list;
220 int i = 0;
221 while (info != NULL) {
222 assert(i < _archived_subgraph_info_records->length(), "sanity");
223 ArchivedKlassSubGraphInfoRecord* record =
224 _archived_subgraph_info_records->adr_at(i);
225 record->init(info);
226 info = info->next();
227 i ++;
228 }
229
230 // _subgraph_info_list is no longer needed
231 delete _subgraph_info_list;
232 _subgraph_info_list = NULL;
233
234 char* end_p = MetaspaceShared::read_only_space_top();
235 size_t records_size = end_p - start_p;
236 return records_size;
237 }
238
239 // Write the subgraph info records in the shared _ro region
240 void HeapShared::write_archived_subgraph_infos() {
241 assert(DumpSharedSpaces, "dump time only");
242
243 Array<intptr_t>* records_header = MetaspaceShared::new_ro_array<intptr_t>(3);
244
245 _num_archived_subgraph_info_records = num_of_subgraph_infos();
246 size_t records_size = build_archived_subgraph_info_records(
247 _num_archived_subgraph_info_records);
248
249 // Now write the header information:
250 // records_size, num_records, _archived_subgraph_info_records
251 assert(records_header != NULL, "sanity");
252 intptr_t* p = (intptr_t*)(records_header->data());
253 *p = (intptr_t)records_size;
254 p ++;
255 *p = (intptr_t)_num_archived_subgraph_info_records;
256 p ++;
257 *p = (intptr_t)_archived_subgraph_info_records;
258 }
259
260 char* HeapShared::read_archived_subgraph_infos(char* buffer) {
261 Array<intptr_t>* records_header = (Array<intptr_t>*)buffer;
262 intptr_t* p = (intptr_t*)(records_header->data());
263 size_t records_size = (size_t)(*p);
264 p ++;
265 _num_archived_subgraph_info_records = *p;
266 p ++;
267 _archived_subgraph_info_records =
268 (Array<ArchivedKlassSubGraphInfoRecord>*)(*p);
269
270 buffer = (char*)_archived_subgraph_info_records + records_size;
271 return buffer;
272 }
273
274 void HeapShared::initialize_from_archived_subgraph(Klass* k) {
275 if (!MetaspaceShared::open_archive_heap_region_mapped()) {
276 return; // nothing to do
277 }
278
279 if (_num_archived_subgraph_info_records == 0) {
280 return; // no subgraph info records
281 }
282
283 // Initialize from archived data. Currently only ArchivedModuleGraph
284 // has archived object subgraphs, which is used during VM initialization
285 // time when bootstraping the system modules. No lock is needed.
286 Thread* THREAD = Thread::current();
287 for (int i = 0; i < _archived_subgraph_info_records->length(); i++) {
288 ArchivedKlassSubGraphInfoRecord* record = _archived_subgraph_info_records->adr_at(i);
289 if (record->klass() == k) {
290 int i;
291 // Found the archived subgraph info record for the requesting klass.
292 // Load/link/initialize the klasses of the objects in the subgraph.
293 // NULL class loader is used.
294 Array<Klass*>* klasses = record->subgraph_klasses();
295 if (klasses != NULL) {
296 for (i = 0; i < klasses->length(); i++) {
297 Klass* obj_k = klasses->at(i);
298 Klass* resolved_k = SystemDictionary::resolve_or_null(
299 (obj_k)->name(), THREAD);
300 if (resolved_k != obj_k) {
301 return;
302 }
303 if ((obj_k)->is_instance_klass()) {
304 InstanceKlass* ik = InstanceKlass::cast(obj_k);
305 ik->initialize(THREAD);
306 } else if ((obj_k)->is_objArray_klass()) {
307 ObjArrayKlass* oak = ObjArrayKlass::cast(obj_k);
308 oak->initialize(THREAD);
309 }
310 }
311 }
312
313 if (HAS_PENDING_EXCEPTION) {
314 CLEAR_PENDING_EXCEPTION;
315 // None of the field value will be set if there was an exception.
316 // The java code will not see any of the archived objects in the
317 // subgraphs referenced from k in this case.
318 return;
319 }
320
321 // Load the subgraph entry fields from the record and store them back to
322 // the corresponding fields within the mirror.
323 oop m = k->java_mirror();
324 Array<juint>* entry_field_records = record->entry_field_records();
325 if (entry_field_records != NULL) {
326 int efr_len = entry_field_records->length();
327 assert(efr_len % 2 == 0, "sanity");
328 for (i = 0; i < efr_len;) {
329 int field_offset = entry_field_records->at(i);
330 // The object refereced by the field becomes 'known' by GC from this
331 // point. All objects in the subgraph reachable from the object are
332 // also 'known' by GC.
333 oop v = MetaspaceShared::materialize_archived_object(
334 entry_field_records->at(i+1));
335 m->obj_field_put(field_offset, v);
336 i += 2;
337 }
338 }
339
340 // Done. Java code can see the archived sub-graphs referenced from k's
341 // mirror after this point.
342 return;
343 }
344 }
345 }
346
347 class WalkOopAndArchiveClosure: public BasicOopIterateClosure {
348 int _level;
349 oop _orig_referencing_obj;
350 oop _archived_referencing_obj;
351 Thread* _thread;
352 public:
353 WalkOopAndArchiveClosure(int level,
354 oop orig, oop archived, TRAPS) : _level(level),
355 _orig_referencing_obj(orig),
356 _archived_referencing_obj(archived),
357 _thread(THREAD) {}
358 void do_oop(narrowOop *p) { WalkOopAndArchiveClosure::do_oop_work(p); }
359 void do_oop( oop *p) { WalkOopAndArchiveClosure::do_oop_work(p); }
360
361 protected:
362 template <class T> void do_oop_work(T *p) {
363 oop obj = RawAccess<>::oop_load(p);
364 if (!CompressedOops::is_null(obj)) {
365 assert(!MetaspaceShared::is_archive_object(obj),
366 "original objects must not directly point to archived object");
367 size_t field_delta = pointer_delta(p, _orig_referencing_obj, sizeof(char));
368 T* new_p = (T*)(address(_archived_referencing_obj) + field_delta);
369
370 // A java.lang.Class instance cannot be included in an archived
371 // object sub-graph.
372 if (java_lang_Class::is_instance(obj)) {
373 log_error(cds, heap)("(%d) Unknown java.lang.Class object is in the archived sub-graph", _level);
374 vm_exit(1);
375 }
376
377 if (log_is_enabled(Debug, cds, heap)) {
378 ResourceMark rm;
379 log_debug(cds, heap)("(%d) %s[" SIZE_FORMAT "] ==> " PTR_FORMAT " size %d %s", _level,
380 _orig_referencing_obj->klass()->external_name(), field_delta,
381 p2i(obj), obj->size() * HeapWordSize, obj->klass()->external_name());
382 LogTarget(Trace, cds, heap) log;
383 LogStream out(log);
384 obj->print_on(&out);
385 }
386
387 oop archived = MetaspaceShared::find_archived_heap_object(obj);
388 if (archived == NULL) {
389 Thread* THREAD = _thread;
390 archived = HeapShared::archive_reachable_objects_from(_level + 1, obj, THREAD);
391 assert(archived != NULL, "VM should have exited");
392 }
393 assert(MetaspaceShared::is_archive_object(archived), "must be");
394
395 // Update the reference in the archived copy of the referencing object.
396 log_debug(cds, heap)("(%d) archiving oop @[" PTR_FORMAT "] " PTR_FORMAT " ==> " PTR_FORMAT,
397 _level, p2i(new_p), p2i(obj), p2i(archived));
398 RawAccess<IS_NOT_NULL>::oop_store(new_p, archived);
399 }
400 }
401 };
402
403 oop HeapShared::archive_reachable_objects_from(int level, oop orig_obj, TRAPS) {
404 assert(orig_obj != NULL, "must be");
405 assert(!MetaspaceShared::is_archive_object(orig_obj), "sanity");
406
407 // get the archived copy of the field referenced object
408 oop archived_obj = MetaspaceShared::archive_heap_object(orig_obj, THREAD);
409 if (archived_obj == NULL) {
410 // Skip archiving the sub-graph referenced from the current entry field.
411 ResourceMark rm;
412 log_error(cds, heap)(
413 "Cannot archive the sub-graph referenced from %s object ("
414 PTR_FORMAT ") size %d, skipped.",
415 orig_obj->klass()->external_name(), p2i(orig_obj), orig_obj->size() * HeapWordSize);
416 if (level == 1) {
417 // See runtime/appcds/cacheObject/ArchivedIntegerCacheTest.java
418 return NULL;
419 } else {
420 // We don't know how to handle an object that has been archived, but some of its reachable
421 // objects cannot be archived. Bail out for now. We might need to fix this in the future if
422 // we have a real use case.
423 vm_exit(1);
424 }
425 }
426
427 WalkOopAndArchiveClosure walker(level, orig_obj, archived_obj, THREAD);
428 orig_obj->oop_iterate(&walker);
429 assert(archived_obj != NULL, "must be");
430 return archived_obj;
431 }
432
433 //
434 // Start from the given static field in a java mirror and archive the
435 // complete sub-graph of java heap objects that are reached directly
436 // or indirectly from the starting object by following references.
437 // Sub-graph archiving restrictions (current):
438 //
439 // - All classes of objects in the archived sub-graph (including the
440 // entry class) must be boot class only.
441 // - No java.lang.Class instance (java mirror) can be included inside
442 // an archived sub-graph. Mirror can only be the sub-graph entry object.
443 //
444 // The Java heap object sub-graph archiving process (see
445 // WalkOopAndArchiveClosure):
446 //
447 // 1) Java object sub-graph archiving starts from a given static field
448 // within a Class instance (java mirror). If the static field is a
449 // refererence field and points to a non-null java object, proceed to
450 // the next step.
451 //
452 // 2) Archives the referenced java object. If an archived copy of the
453 // current object already exists, updates the pointer in the archived
454 // copy of the referencing object to point to the current archived object.
455 // Otherwise, proceed to the next step.
456 //
457 // 3) Follows all references within the current java object and recursively
458 // archive the sub-graph of objects starting from each reference.
459 //
460 // 4) Updates the pointer in the archived copy of referencing object to
461 // point to the current archived object.
462 void HeapShared::archive_reachable_objects_from_static_field(InstanceKlass *k,
463 const char* klass_name,
464 int field_offset,
465 const char* field_name,
466 TRAPS) {
467 assert(DumpSharedSpaces, "dump time only");
468 assert(k->is_shared_boot_class(), "must be boot class");
469
470 oop m = k->java_mirror();
471 oop archived_m = MetaspaceShared::find_archived_heap_object(m);
472 if (CompressedOops::is_null(archived_m)) {
473 return;
474 }
475
476 KlassSubGraphInfo* subgraph_info = get_subgraph_info(k);
477 oop f = m->obj_field(field_offset);
478
479 log_debug(cds, heap)("Start archiving from: %s::%s ", klass_name, field_name);
480 if (log_is_enabled(Trace, cds, heap) && !CompressedOops::is_null(f)) {
481 LogTarget(Trace, cds, heap) log;
482 LogStream out(log);
483 f->print_on(&out);
484 }
485
486 if (!CompressedOops::is_null(f)) {
487 oop af = archive_reachable_objects_from(1, f, CHECK);
488 if (af == NULL) {
489 log_error(cds, heap)("Archiving failed %s::%s (some reachable objects cannot be archived)",
490 klass_name, field_name);
491 } else {
492 // Note: the field value is not preserved in the archived mirror.
493 // Record the field as a new subGraph entry point. The recorded
494 // information is restored from the archive at runtime.
495 subgraph_info->add_subgraph_entry_field(field_offset, af);
496 log_info(cds, heap)("Archived field %s::%s => " PTR_FORMAT, klass_name, field_name, p2i(af));
497 }
498 } else {
499 // The field contains null, we still need to record the entry point,
500 // so it can be restored at runtime.
501 subgraph_info->add_subgraph_entry_field(field_offset, NULL);
502 }
503 }
504
505 HeapShared::SeenObjectsTable* HeapShared::_seen_objects_table = NULL;
506
507 bool HeapShared::has_been_seen_during_subgraph_klasses_recording(oop obj) {
508 if (_seen_objects_table->get(obj) == NULL) {
509 _seen_objects_table->put(obj, true);
510 return false;
511 } else {
512 return true;
513 }
514 }
515
516 void HeapShared::start_recording_subgraph_klasses(InstanceKlass *k, const char* class_name) {
517 log_info(cds, heap)("Record classes for archived fields in %s", class_name);
518 assert(_seen_objects_table == NULL, "must be");
519 _seen_objects_table = new (ResourceObj::C_HEAP, mtClass)SeenObjectsTable();
520 }
521
522 void HeapShared::done_recording_subgraph_klasses(InstanceKlass *k) {
523 delete _seen_objects_table;
524 _seen_objects_table = NULL;
525 }
526
527 void HeapShared::record_subgraph_klasses_from_static_field(InstanceKlass *k,
528 const char* klass_name,
529 int field_offset,
530 const char* field_name) {
531 assert(DumpSharedSpaces, "dump time only");
532 assert(k->is_shared_boot_class(), "must be boot class");
533
534 log_debug(cds, heap)("Start recording from: %s::%s", klass_name, field_name);
535
536 oop m = k->java_mirror();
537 oop f = m->obj_field(field_offset);
538 record_subgraph_klasses_for(get_subgraph_info(k), f);
539 }
540
541 class RecordKlassesClosure: public BasicOopIterateClosure {
542 KlassSubGraphInfo* _subgraph_info;
543 public:
544 RecordKlassesClosure(KlassSubGraphInfo* subgraph_info) :
545 _subgraph_info(subgraph_info) {}
546 void do_oop(narrowOop *p) { do_oop_work(p); }
547 void do_oop( oop *p) { do_oop_work(p); }
548
549 protected:
550 template <class T> void do_oop_work(T *p) {
551 oop obj = RawAccess<>::oop_load(p);
552 if (!CompressedOops::is_null(obj)) {
553 assert(!java_lang_Class::is_instance(obj), "should have been excluded");
554
555 if (!HeapShared::has_been_seen_during_subgraph_klasses_recording(obj)) {
556 HeapShared::record_subgraph_klasses_for(_subgraph_info, obj);
557 }
558 }
559 }
560 };
561
562 void HeapShared::record_subgraph_klasses_for(KlassSubGraphInfo* subgraph_info, oop obj) {
563 assert(!java_lang_Class::is_instance(obj), "should have been excluded");
564
565 if (!CompressedOops::is_null(obj)) {
566 oop archived = MetaspaceShared::find_archived_heap_object(obj);
567 if (CompressedOops::is_null(archived)) {
568 // Object was skipped because it was too big
569 return;
570 }
571
572 Klass *orig_k = obj->klass();
573 Klass *relocated_k = archived->klass();
574 subgraph_info->add_subgraph_klass(orig_k, relocated_k);
575
576 RecordKlassesClosure walker(subgraph_info);
577 obj->oop_iterate(&walker);
578 }
579 }
580
581 struct ArchivableStaticFieldInfo {
582 const char* klass_name;
583 const char* field_name;
584 InstanceKlass* klass;
585 int offset;
586 BasicType type;
587 };
588
589 // If you add new entries to this table, you should know what you're doing!
590 static ArchivableStaticFieldInfo archivable_static_fields[] = {
591 {"jdk/internal/module/ArchivedModuleGraph", "archivedSystemModules"},
592 {"jdk/internal/module/ArchivedModuleGraph", "archivedModuleFinder"},
593 {"jdk/internal/module/ArchivedModuleGraph", "archivedMainModule"},
594 {"jdk/internal/module/ArchivedModuleGraph", "archivedConfiguration"},
595 {"java/util/ImmutableCollections$ListN", "EMPTY_LIST"},
596 {"java/util/ImmutableCollections$MapN", "EMPTY_MAP"},
597 {"java/util/ImmutableCollections$SetN", "EMPTY_SET"},
598 {"java/lang/Integer$IntegerCache", "archivedCache"},
599 {"java/lang/module/Configuration", "EMPTY_CONFIGURATION"},
600 };
601
602 const static int num_archivable_static_fields = sizeof(archivable_static_fields) / sizeof(ArchivableStaticFieldInfo);
603
604 class ArchivableStaticFieldFinder: public FieldClosure {
605 InstanceKlass* _ik;
606 Symbol* _field_name;
607 bool _found;
608 int _offset;
609 BasicType _type;
610 public:
611 ArchivableStaticFieldFinder(InstanceKlass* ik, Symbol* field_name) :
612 _ik(ik), _field_name(field_name), _found(false), _offset(-1), _type(T_ILLEGAL) {}
613
614 virtual void do_field(fieldDescriptor* fd) {
615 if (fd->name() == _field_name) {
616 assert(!_found, "fields cannot be overloaded");
617 _found = true;
618 _offset = fd->offset();
619 _type = fd->field_type();
620 assert(_type == T_OBJECT || _type == T_ARRAY, "can archive only obj or array fields");
621 }
622 }
623 bool found() { return _found; }
624 int offset() { return _offset; }
625 BasicType type() { return _type; }
626 };
627
628 void HeapShared::init_archivable_static_fields(Thread* THREAD) {
629 for (int i = 0; i < num_archivable_static_fields; i++) {
630 ArchivableStaticFieldInfo* info = &archivable_static_fields[i];
631 TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name, THREAD);
632 TempNewSymbol field_name = SymbolTable::new_symbol(info->field_name, THREAD);
633
634 Klass* k = SystemDictionary::resolve_or_null(klass_name, THREAD);
635 assert(k != NULL && !HAS_PENDING_EXCEPTION, "class must exist");
636 InstanceKlass* ik = InstanceKlass::cast(k);
637
638 ArchivableStaticFieldFinder finder(ik, field_name);
639 ik->do_local_static_fields(&finder);
640 assert(finder.found(), "field must exist");
641
642 info->klass = ik;
643 info->offset = finder.offset();
644 info->type = finder.type();
645
646 assert(info->type == T_OBJECT || info->type == T_ARRAY, "must be");
647 }
648 }
649
650 void HeapShared::archive_module_graph_objects(Thread* THREAD) {
651 for (int i = 0; i < num_archivable_static_fields; i++) {
652 ArchivableStaticFieldInfo* info = &archivable_static_fields[i];
653 archive_reachable_objects_from_static_field(info->klass, info->klass_name,
654 info->offset, info->field_name, CHECK);
655 }
656
657 record_subgraph_klasses();
658 }
659
660 // For each class X that has one or more archived fields, create a list of
661 // all the class of the objects that can be reached by any of these static
662 // fields.
663 //
664 // At runtime, these classes are initialized before X's archived fields
665 // are restored by HeapShared::initialize_from_archived_subgraph().
666 void HeapShared::record_subgraph_klasses() {
667 for (int i = 0; i < num_archivable_static_fields; ) {
668 ArchivableStaticFieldInfo* info = &archivable_static_fields[i];
669 const char* klass_name = info->klass_name;
670 start_recording_subgraph_klasses(info->klass, klass_name);
671
672 int j = i;
673 while (j < num_archivable_static_fields) {
674 ArchivableStaticFieldInfo* f = &archivable_static_fields[j];
675 if (f->klass_name == klass_name) {
676 record_subgraph_klasses_from_static_field(f->klass, f->klass_name,
677 f->offset, f->field_name);
678 j++;
679 } else {
680 break;
681 }
682 }
683 done_recording_subgraph_klasses(info->klass);
684 i = j;
685 }
686 }
687
688 // At dump-time, find the location of all the non-null oop pointers in an archived heap
689 // region. This way we can quickly relocate all the pointers without using
690 // BasicOopIterateClosure at runtime.
691 class FindEmbeddedNonNullPointers: public BasicOopIterateClosure {
692 narrowOop* _start;
693 BitMap *_oopmap;
694 int _num_total_oops;
695 int _num_null_oops;
696 public:
697 FindEmbeddedNonNullPointers(narrowOop* start, BitMap* oopmap)
698 : _start(start), _oopmap(oopmap), _num_total_oops(0), _num_null_oops(0) {}
699
700 virtual bool should_verify_oops(void) {
701 return false;
702 }
703 virtual void do_oop(narrowOop* p) {
704 _num_total_oops ++;
705 narrowOop v = *p;
706 if (!CompressedOops::is_null(v)) {
707 size_t idx = p - _start;
708 _oopmap->set_bit(idx);
709 } else {
710 _num_null_oops ++;
711 }
712 }
713 virtual void do_oop(oop *p) {
714 ShouldNotReachHere();
715 }
716 int num_total_oops() const { return _num_total_oops; }
717 int num_null_oops() const { return _num_null_oops; }
718 };
719
720 ResourceBitMap HeapShared::calculate_oopmap(MemRegion region) {
721 assert(UseCompressedOops, "must be");
722 size_t num_bits = region.byte_size() / sizeof(narrowOop);
723 ResourceBitMap oopmap(num_bits);
724
725 HeapWord* p = region.start();
726 HeapWord* end = region.end();
727 FindEmbeddedNonNullPointers finder((narrowOop*)p, &oopmap);
728
729 int num_objs = 0;
730 while (p < end) {
731 oop o = (oop)p;
732 o->oop_iterate(&finder);
733 p += o->size();
734 ++ num_objs;
735 }
736
737 log_info(cds, heap)("calculate_oopmap: objects = %6d, embedded oops = %7d, nulls = %7d",
738 num_objs, finder.num_total_oops(), finder.num_null_oops());
739 return oopmap;
740 }
741
742 void HeapShared::init_narrow_oop_decoding(address base, int shift) {
743 _narrow_oop_base = base;
744 _narrow_oop_shift = shift;
745 }
746
747 // Patch all the embedded oop pointers inside an archived heap region,
748 // to be consistent with the runtime oop encoding.
749 class PatchEmbeddedPointers: public BitMapClosure {
750 narrowOop* _start;
751
752 public:
753 PatchEmbeddedPointers(narrowOop* start) : _start(start) {}
754
755 bool do_bit(size_t offset) {
756 narrowOop* p = _start + offset;
757 narrowOop v = *p;
758 assert(!CompressedOops::is_null(v), "null oops should have been filtered out at dump time");
759 oop o = HeapShared::decode_with_archived_oop_encoding_mode(v);
760 RawAccess<IS_NOT_NULL>::oop_store(p, o);
761 return true;
762 }
763 };
764
765 void HeapShared::patch_archived_heap_embedded_pointers(MemRegion region, address oopmap,
766 size_t oopmap_size_in_bits) {
767 BitMapView bm((BitMap::bm_word_t*)oopmap, oopmap_size_in_bits);
768
769 #ifndef PRODUCT
770 ResourceMark rm;
771 ResourceBitMap checkBm = calculate_oopmap(region);
772 assert(bm.is_same(checkBm), "sanity");
773 #endif
774
775 PatchEmbeddedPointers patcher((narrowOop*)region.start());
776 bm.iterate(&patcher);
777 }
778
779 #endif // INCLUDE_CDS_JAVA_HEAP