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 (%d): %s in %s sub-graphs",
189 i, subgraph_k->external_name(), _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 public:
352 WalkOopAndArchiveClosure(int level,
353 oop orig, oop archived) : _level(level),
354 _orig_referencing_obj(orig),
355 _archived_referencing_obj(archived) {}
356 void do_oop(narrowOop *p) { WalkOopAndArchiveClosure::do_oop_work(p); }
357 void do_oop( oop *p) { WalkOopAndArchiveClosure::do_oop_work(p); }
358
359 protected:
360 template <class T> void do_oop_work(T *p) {
361 oop obj = RawAccess<>::oop_load(p);
362 if (!CompressedOops::is_null(obj)) {
363 // A java.lang.Class instance cannot be included in an archived
364 // object sub-graph.
365 if (java_lang_Class::is_instance(obj)) {
366 log_error(cds, heap)("Unknown java.lang.Class object is in the archived sub-graph");
367 vm_exit(1);
368 }
369
370 if (log_is_enabled(Debug, cds, heap)) {
371 LogTarget(Debug, cds, heap) log;
372 LogStream ls(log);
373 outputStream* out = &ls;
374 ResourceMark rm;
375 log.print("(%d) %s <--- referenced from: %s",
376 _level, obj->klass()->external_name(),
377 CompressedOops::is_null(_orig_referencing_obj) ?
378 "" : _orig_referencing_obj->klass()->external_name());
379 obj->print_on(out);
380 }
381
382 assert(!MetaspaceShared::is_archive_object(obj),
383 "original objects must not directly point to archived object");
384
385 size_t field_delta = pointer_delta(
386 p, _orig_referencing_obj, sizeof(char));
387 T* new_p = (T*)(address(_archived_referencing_obj) + field_delta);
388 oop archived = MetaspaceShared::find_archived_heap_object(obj);
389 if (archived != NULL) {
390 // There is an archived copy existing, update reference to point
391 // to the archived copy
392 RawAccess<IS_NOT_NULL>::oop_store(new_p, archived);
393 log_debug(cds, heap)("--- found existing archived copy, store archived " PTR_FORMAT " in " PTR_FORMAT,
394 p2i(archived), p2i(new_p));
395 return;
396 }
397
398 Thread* THREAD = Thread::current();
399 // Archive the current oop before iterating through its references
400 archived = MetaspaceShared::archive_heap_object(obj, THREAD);
401 if (archived == NULL) {
402 ResourceMark rm;
403 LogTarget(Error, cds, heap) log_err;
404 LogStream ls_err(log_err);
405 outputStream* out_err = &ls_err;
406 log_err.print("Failed to archive %s object ("
407 PTR_FORMAT "), size[" SIZE_FORMAT "] in sub-graph",
408 obj->klass()->external_name(), p2i(obj), (size_t)obj->size());
409 obj->print_on(out_err);
410 vm_exit(1);
411 }
412 assert(MetaspaceShared::is_archive_object(archived), "must be archived");
413 log_debug(cds, heap)("=== archiving oop " PTR_FORMAT " ==> " PTR_FORMAT,
414 p2i(obj), p2i(archived));
415
416 // Following the references in the current oop and archive any
417 // encountered objects during the process
418 WalkOopAndArchiveClosure walker(_level + 1, obj, archived);
419 obj->oop_iterate(&walker);
420
421 // Update the reference in the archived copy of the referencing object
422 RawAccess<IS_NOT_NULL>::oop_store(new_p, archived);
423 log_debug(cds,heap)("=== store archived " PTR_FORMAT " in " PTR_FORMAT,
424 p2i(archived), p2i(new_p));
425 }
426 }
427 };
428
429 //
430 // Start from the given static field in a java mirror and archive the
431 // complete sub-graph of java heap objects that are reached directly
432 // or indirectly from the starting object by following references.
433 // Currently, only ArchivedModuleGraph class instance (mirror) has archived
434 // object subgraphs. Sub-graph archiving restrictions (current):
435 //
436 // - All classes of objects in the archived sub-graph (including the
437 // entry class) must be boot class only.
438 // - No java.lang.Class instance (java mirror) can be included inside
439 // an archived sub-graph. Mirror can only be the sub-graph entry object.
440 //
441 // The Java heap object sub-graph archiving process (see
442 // WalkOopAndArchiveClosure):
443 //
444 // 1) Java object sub-graph archiving starts from a given static field
445 // within a Class instance (java mirror). If the static field is a
446 // refererence field and points to a non-null java object, proceed to
447 // the next step.
448 //
449 // 2) Archives the referenced java object. If an archived copy of the
450 // current object already exists, updates the pointer in the archived
451 // copy of the referencing object to point to the current archived object.
452 // Otherwise, proceed to the next step.
453 //
454 // 3) Follows all references within the current java object and recursively
455 // archive the sub-graph of objects starting from each reference.
456 //
457 // 4) Updates the pointer in the archived copy of referencing object to
458 // point to the current archived object.
459 void HeapShared::archive_reachable_objects_from_static_field(InstanceKlass *k,
460 const char* klass_name,
461 int field_offset,
462 const char* field_name,
463 TRAPS) {
464 assert(DumpSharedSpaces, "dump time only");
465 assert(k->is_shared_boot_class(), "must be boot class");
466
467 oop m = k->java_mirror();
468 oop archived_m = MetaspaceShared::find_archived_heap_object(m);
469 if (CompressedOops::is_null(archived_m)) {
470 return;
471 }
472
473 // obtain k's subGraph Info
474 KlassSubGraphInfo* subgraph_info = get_subgraph_info(k);
475
476 // get the object referenced by the field
477 oop f = m->obj_field(field_offset);
478
479 if (log_is_enabled(Debug, cds, heap)) {
480 LogTarget(Debug, cds, heap) log;
481 LogStream ls(log);
482 outputStream* out = &ls;
483 log.print("Start archiving from: %s::%s ", klass_name, field_name);
484 if (!CompressedOops::is_null(f)) {
485 f->print_on(out);
486 } else {
487 log.print("null");
488 }
489 }
490
491 if (!CompressedOops::is_null(f)) {
492 // get the archived copy of the field referenced object
493 oop af = MetaspaceShared::archive_heap_object(f, THREAD);
494 if (af == NULL) {
495 // Skip archiving the sub-graph referenced from the current entry field.
496 ResourceMark rm;
497 log_info(cds, heap)(
498 "Cannot archive the sub-graph referenced from %s object ("
499 PTR_FORMAT ") size[" SIZE_FORMAT "], skipped.",
500 f->klass()->external_name(), p2i(f), (size_t)f->size());
501 return;
502 }
503 if (!MetaspaceShared::is_archive_object(f)) {
504 WalkOopAndArchiveClosure walker(1, f, af);
505 f->oop_iterate(&walker);
506 }
507
508 // The field value is not preserved in the archived mirror.
509 // Record the field as a new subGraph entry point. The recorded
510 // information is restored from the archive at runtime.
511 subgraph_info->add_subgraph_entry_field(field_offset, af);
512 if (log_is_enabled(Info, cds, heap)) {
513 ResourceMark rm;
514 log_info(cds, heap)(
515 "Archived the sub-graph referenced from %s object " PTR_FORMAT,
516 f->klass()->external_name(), p2i(f));
517 }
518 } else {
519 // The field contains null, we still need to record the entry point,
520 // so it can be restored at runtime.
521 subgraph_info->add_subgraph_entry_field(field_offset, NULL);
522 }
523 }
524
525 HeapShared::SeenObjectsTable* HeapShared::_seen_objects_table = NULL;
526
527 bool HeapShared::has_been_seen_during_subgraph_klasses_recording(oop obj) {
528 if (_seen_objects_table->get(obj) == NULL) {
529 _seen_objects_table->put(obj, true);
530 return false;
531 } else {
532 return true;
533 }
534 }
535
536 void HeapShared::start_recording_subgraph_klasses(InstanceKlass *k, const char* class_name) {
537 log_info(cds, heap)("Record classes for archived fields in %s", class_name);
538 assert(_seen_objects_table == NULL, "must be");
539 _seen_objects_table = new (ResourceObj::C_HEAP, mtClass)SeenObjectsTable();
540 }
541
542 void HeapShared::done_recording_subgraph_klasses(InstanceKlass *k) {
543 delete _seen_objects_table;
544 _seen_objects_table = NULL;
545 }
546
547 void HeapShared::record_subgraph_klasses_from_static_field(InstanceKlass *k,
548 const char* klass_name,
549 int field_offset,
550 const char* field_name) {
551 assert(DumpSharedSpaces, "dump time only");
552 assert(k->is_shared_boot_class(), "must be boot class");
553
554 if (log_is_enabled(Debug, cds, heap)) {
555 LogTarget(Debug, cds, heap) log;
556 LogStream ls(log);
557 outputStream* out = &ls;
558 log.print("Start recording from: %s::%s", klass_name, field_name);
559 }
560
561 oop m = k->java_mirror();
562 oop f = m->obj_field(field_offset);
563 record_subgraph_klasses_for(get_subgraph_info(k), f);
564 }
565
566 class RecordKlassesClosure: public BasicOopIterateClosure {
567 KlassSubGraphInfo* _subgraph_info;
568 public:
569 RecordKlassesClosure(KlassSubGraphInfo* subgraph_info) :
570 _subgraph_info(subgraph_info) {}
571 void do_oop(narrowOop *p) { do_oop_work(p); }
572 void do_oop( oop *p) { do_oop_work(p); }
573
574 protected:
575 template <class T> void do_oop_work(T *p) {
576 oop obj = RawAccess<>::oop_load(p);
577 if (!CompressedOops::is_null(obj)) {
578 assert(!java_lang_Class::is_instance(obj), "should have been excluded");
579
580 if (!HeapShared::has_been_seen_during_subgraph_klasses_recording(obj)) {
581 HeapShared::record_subgraph_klasses_for(_subgraph_info, obj);
582 }
583 }
584 }
585 };
586
587 void HeapShared::record_subgraph_klasses_for(KlassSubGraphInfo* subgraph_info, oop obj) {
588 assert(!java_lang_Class::is_instance(obj), "should have been excluded");
589
590 if (!CompressedOops::is_null(obj)) {
591 oop archived = MetaspaceShared::find_archived_heap_object(obj);
592 if (CompressedOops::is_null(archived)) {
593 // Object was skipped because it was too big
594 return;
595 }
596
597 Klass *orig_k = obj->klass();
598 Klass *relocated_k = archived->klass();
599 subgraph_info->add_subgraph_klass(orig_k, relocated_k);
600
601 RecordKlassesClosure walker(subgraph_info);
602 obj->oop_iterate(&walker);
603 }
604 }
605
606 struct ArchivableStaticFieldInfo {
607 const char* klass_name;
608 const char* field_name;
609 InstanceKlass* klass;
610 int offset;
611 BasicType type;
612 };
613
614 // If you add new entries to this table, you should know what you're doing!
615 static ArchivableStaticFieldInfo archivable_static_fields[] = {
616 {"jdk/internal/module/ArchivedModuleGraph", "archivedSystemModules"},
617 {"jdk/internal/module/ArchivedModuleGraph", "archivedModuleFinder"},
618 {"jdk/internal/module/ArchivedModuleGraph", "archivedMainModule"},
619 {"jdk/internal/module/ArchivedModuleGraph", "archivedConfiguration"},
620 {"java/util/ImmutableCollections$ListN", "EMPTY_LIST"},
621 {"java/util/ImmutableCollections$MapN", "EMPTY_MAP"},
622 {"java/util/ImmutableCollections$SetN", "EMPTY_SET"},
623 {"java/lang/Integer$IntegerCache", "archivedCache"},
624 {"java/lang/module/Configuration", "EMPTY_CONFIGURATION"},
625 };
626
627 const static int num_archivable_static_fields = sizeof(archivable_static_fields) / sizeof(ArchivableStaticFieldInfo);
628
629 class ArchivableStaticFieldFinder: public FieldClosure {
630 InstanceKlass* _ik;
631 Symbol* _field_name;
632 bool _found;
633 int _offset;
634 BasicType _type;
635 public:
636 ArchivableStaticFieldFinder(InstanceKlass* ik, Symbol* field_name) :
637 _ik(ik), _field_name(field_name), _found(false), _offset(-1), _type(T_ILLEGAL) {}
638
639 virtual void do_field(fieldDescriptor* fd) {
640 if (fd->name() == _field_name) {
641 assert(!_found, "fields cannot be overloaded");
642 _found = true;
643 _offset = fd->offset();
644 _type = fd->field_type();
645 assert(_type == T_OBJECT || _type == T_ARRAY, "can archive only obj or array fields");
646 }
647 }
648 bool found() { return _found; }
649 int offset() { return _offset; }
650 BasicType type() { return _type; }
651 };
652
653 void HeapShared::init_archivable_static_fields(Thread* THREAD) {
654 for (int i = 0; i < num_archivable_static_fields; i++) {
655 ArchivableStaticFieldInfo* info = &archivable_static_fields[i];
656 TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name, THREAD);
657 TempNewSymbol field_name = SymbolTable::new_symbol(info->field_name, THREAD);
658
659 Klass* k = SystemDictionary::resolve_or_null(klass_name, THREAD);
660 assert(k != NULL && !HAS_PENDING_EXCEPTION, "class must exist");
661 InstanceKlass* ik = InstanceKlass::cast(k);
662
663 ArchivableStaticFieldFinder finder(ik, field_name);
664 ik->do_local_static_fields(&finder);
665 assert(finder.found(), "field must exist");
666
667 info->klass = ik;
668 info->offset = finder.offset();
669 info->type = finder.type();
670
671 assert(info->type == T_OBJECT || info->type == T_ARRAY, "must be");
672 }
673 }
674
675 void HeapShared::archive_module_graph_objects(Thread* THREAD) {
676 for (int i = 0; i < num_archivable_static_fields; i++) {
677 ArchivableStaticFieldInfo* info = &archivable_static_fields[i];
678 archive_reachable_objects_from_static_field(info->klass, info->klass_name,
679 info->offset, info->field_name, CHECK);
680 }
681
682 record_subgraph_klasses();
683 }
684
685 // For each class X that has one or more archived fields, create a list of
686 // all the class of the objects that can be reached by any of these static
687 // fields.
688 //
689 // At runtime, these classes are initialized before X's archived fields
690 // are restored by HeapShared::initialize_from_archived_subgraph().
691 void HeapShared::record_subgraph_klasses() {
692 for (int i = 0; i < num_archivable_static_fields; ) {
693 ArchivableStaticFieldInfo* info = &archivable_static_fields[i];
694 const char* klass_name = info->klass_name;
695 start_recording_subgraph_klasses(info->klass, klass_name);
696
697 int j = i;
698 while (j < num_archivable_static_fields) {
699 ArchivableStaticFieldInfo* f = &archivable_static_fields[j];
700 if (f->klass_name == klass_name) {
701 record_subgraph_klasses_from_static_field(f->klass, f->klass_name,
702 f->offset, f->field_name);
703 j++;
704 } else {
705 break;
706 }
707 }
708 done_recording_subgraph_klasses(info->klass);
709 i = j;
710 }
711 }
712
713 // At dump-time, find the location of all the non-null oop pointers in an archived heap
714 // region. This way we can quickly relocate all the pointers without using
715 // BasicOopIterateClosure at runtime.
716 class FindEmbeddedNonNullPointers: public BasicOopIterateClosure {
717 narrowOop* _start;
718 BitMap *_oopmap;
719 int _num_total_oops;
720 int _num_null_oops;
721 public:
722 FindEmbeddedNonNullPointers(narrowOop* start, BitMap* oopmap)
723 : _start(start), _oopmap(oopmap), _num_total_oops(0), _num_null_oops(0) {}
724
725 virtual bool should_verify_oops(void) {
726 return false;
727 }
728 virtual void do_oop(narrowOop* p) {
729 _num_total_oops ++;
730 narrowOop v = *p;
731 if (!CompressedOops::is_null(v)) {
732 size_t idx = p - _start;
733 _oopmap->set_bit(idx);
734 } else {
735 _num_null_oops ++;
736 }
737 }
738 virtual void do_oop(oop *p) {
739 ShouldNotReachHere();
740 }
741 int num_total_oops() const { return _num_total_oops; }
742 int num_null_oops() const { return _num_null_oops; }
743 };
744
745 ResourceBitMap HeapShared::calculate_oopmap(MemRegion region) {
746 assert(UseCompressedOops, "must be");
747 size_t num_bits = region.byte_size() / sizeof(narrowOop);
748 ResourceBitMap oopmap(num_bits);
749
750 HeapWord* p = region.start();
751 HeapWord* end = region.end();
752 FindEmbeddedNonNullPointers finder((narrowOop*)p, &oopmap);
753
754 int num_objs = 0;
755 while (p < end) {
756 oop o = (oop)p;
757 o->oop_iterate(&finder);
758 p += o->size();
759 ++ num_objs;
760 }
761
762 log_info(cds, heap)("calculate_oopmap: objects = %6d, embedded oops = %7d, nulls = %7d",
763 num_objs, finder.num_total_oops(), finder.num_null_oops());
764 return oopmap;
765 }
766
767 void HeapShared::init_narrow_oop_decoding(address base, int shift) {
768 _narrow_oop_base = base;
769 _narrow_oop_shift = shift;
770 }
771
772 // Patch all the embedded oop pointers inside an archived heap region,
773 // to be consistent with the runtime oop encoding.
774 class PatchEmbeddedPointers: public BitMapClosure {
775 narrowOop* _start;
776
777 public:
778 PatchEmbeddedPointers(narrowOop* start) : _start(start) {}
779
780 bool do_bit(size_t offset) {
781 narrowOop* p = _start + offset;
782 narrowOop v = *p;
783 assert(!CompressedOops::is_null(v), "null oops should have been filtered out at dump time");
784 oop o = HeapShared::decode_with_archived_oop_encoding_mode(v);
785 RawAccess<IS_NOT_NULL>::oop_store(p, o);
786 return true;
787 }
788 };
789
790 void HeapShared::patch_archived_heap_embedded_pointers(MemRegion region, address oopmap,
791 size_t oopmap_size_in_bits) {
792 BitMapView bm((BitMap::bm_word_t*)oopmap, oopmap_size_in_bits);
793
794 #ifndef PRODUCT
795 ResourceMark rm;
796 ResourceBitMap checkBm = calculate_oopmap(region);
797 assert(bm.is_same(checkBm), "sanity");
798 #endif
799
800 PatchEmbeddedPointers patcher((narrowOop*)region.start());
801 bm.iterate(&patcher);
802 }
803
804 #endif // INCLUDE_CDS_JAVA_HEAP