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