1 /*
2 * Copyright (c) 2018, 2020, 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/classLoaderData.hpp"
27 #include "classfile/classLoaderDataShared.hpp"
28 #include "classfile/javaClasses.inline.hpp"
29 #include "classfile/moduleEntry.hpp"
30 #include "classfile/stringTable.hpp"
31 #include "classfile/symbolTable.hpp"
32 #include "classfile/systemDictionary.hpp"
33 #include "classfile/systemDictionaryShared.hpp"
34 #include "classfile/vmSymbols.hpp"
35 #include "gc/shared/gcLocker.hpp"
36 #include "logging/log.hpp"
37 #include "logging/logMessage.hpp"
38 #include "logging/logStream.hpp"
39 #include "memory/archiveBuilder.hpp"
40 #include "memory/archiveUtils.hpp"
41 #include "memory/filemap.hpp"
42 #include "memory/heapShared.inline.hpp"
43 #include "memory/iterator.inline.hpp"
44 #include "memory/metadataFactory.hpp"
45 #include "memory/metaspaceClosure.hpp"
46 #include "memory/metaspaceShared.hpp"
47 #include "memory/resourceArea.hpp"
48 #include "memory/universe.hpp"
49 #include "oops/compressedOops.inline.hpp"
50 #include "oops/fieldStreams.inline.hpp"
51 #include "oops/objArrayOop.hpp"
52 #include "oops/oop.inline.hpp"
53 #include "oops/oopHandle.hpp"
54 #include "runtime/fieldDescriptor.inline.hpp"
55 #include "runtime/init.hpp"
56 #include "runtime/javaCalls.hpp"
57 #include "runtime/safepointVerifiers.hpp"
58 #include "utilities/bitMap.inline.hpp"
59 #if INCLUDE_G1GC
60 #include "gc/g1/g1CollectedHeap.hpp"
61 #endif
62
63 #if INCLUDE_CDS_JAVA_HEAP
64
65 bool HeapShared::_closed_archive_heap_region_mapped = false;
66 bool HeapShared::_open_archive_heap_region_mapped = false;
67 bool HeapShared::_archive_heap_region_fixed = false;
68 address HeapShared::_narrow_oop_base;
69 int HeapShared::_narrow_oop_shift;
70 DumpedInternedStrings *HeapShared::_dumped_interned_strings = NULL;
71
72 //
73 // If you add new entries to the following tables, you should know what you're doing!
74 //
75
76 // Entry fields for shareable subgraphs archived in the closed archive heap
77 // region. Warning: Objects in the subgraphs should not have reference fields
78 // assigned at runtime.
79 static ArchivableStaticFieldInfo closed_archive_subgraph_entry_fields[] = {
80 {"java/lang/Integer$IntegerCache", "archivedCache"},
81 {"java/lang/Long$LongCache", "archivedCache"},
82 {"java/lang/Byte$ByteCache", "archivedCache"},
83 {"java/lang/Short$ShortCache", "archivedCache"},
84 {"java/lang/Character$CharacterCache", "archivedCache"},
85 {"java/util/jar/Attributes$Name", "KNOWN_NAMES"},
86 {"sun/util/locale/BaseLocale", "constantBaseLocales"},
87 };
88 // Entry fields for subgraphs archived in the open archive heap region.
89 static ArchivableStaticFieldInfo open_archive_subgraph_entry_fields[] = {
90 {"jdk/internal/module/ArchivedModuleGraph", "archivedModuleGraph"},
91 {"java/util/ImmutableCollections", "archivedObjects"},
92 {"java/lang/module/Configuration", "EMPTY_CONFIGURATION"},
93 {"jdk/internal/math/FDBigInteger", "archivedCaches"},
94 };
95
96 // Entry fields for subgraphs archived in the open archive heap region (full module graph).
97 static ArchivableStaticFieldInfo fmg_open_archive_subgraph_entry_fields[] = {
98 {"jdk/internal/loader/ArchivedClassLoaders", "archivedClassLoaders"},
99 {"jdk/internal/module/ArchivedBootLayer", "archivedBootLayer"},
100 {"java/lang/Module$ArchivedData", "archivedData"},
101 };
102
103 const static int num_closed_archive_subgraph_entry_fields =
104 sizeof(closed_archive_subgraph_entry_fields) / sizeof(ArchivableStaticFieldInfo);
105 const static int num_open_archive_subgraph_entry_fields =
106 sizeof(open_archive_subgraph_entry_fields) / sizeof(ArchivableStaticFieldInfo);
107 const static int num_fmg_open_archive_subgraph_entry_fields =
108 sizeof(fmg_open_archive_subgraph_entry_fields) / sizeof(ArchivableStaticFieldInfo);
109
110 static GrowableArrayCHeap<oop, mtClassShared>* _pending_roots = NULL;
111 static objArrayOop _dumptime_roots = NULL; // FIXME -- combine this with _runtime_roots??
112 static narrowOop _runtime_roots_narrow;
113 static OopHandle _runtime_roots;
114
115 ////////////////////////////////////////////////////////////////
116 //
117 // Java heap object archiving support
118 //
119 ////////////////////////////////////////////////////////////////
120 void HeapShared::fixup_mapped_heap_regions() {
121 FileMapInfo *mapinfo = FileMapInfo::current_info();
122 mapinfo->fixup_mapped_heap_regions();
123 set_archive_heap_region_fixed();
124 if (is_mapped()) {
125 _runtime_roots = OopHandle(Universe::vm_global(), HeapShared::materialize_archived_object(_runtime_roots_narrow));
126 if (!MetaspaceShared::use_full_module_graph()) {
127 // Need to remove all the archived java.lang.Module objects from HeapShared::roots().
128 ClassLoaderDataShared::clear_archived_oops();
129 }
130 }
131 SystemDictionaryShared::update_archived_mirror_native_pointers();
132 }
133
134 unsigned HeapShared::oop_hash(oop const& p) {
135 assert(!p->mark().has_bias_pattern(),
136 "this object should never have been locked"); // so identity_hash won't safepoin
137 unsigned hash = (unsigned)p->identity_hash();
138 return hash;
139 }
140
141 static void reset_states(oop obj, TRAPS) {
142 Handle h_obj(THREAD, obj);
143 InstanceKlass* klass = InstanceKlass::cast(obj->klass());
144 TempNewSymbol method_name = SymbolTable::new_symbol("resetArchivedStates");
145 Symbol* method_sig = vmSymbols::void_method_signature();
146
147 while (klass != NULL) {
148 Method* method = klass->find_method(method_name, method_sig);
149 if (method != NULL) {
150 assert(method->is_private(), "must be");
151 if (log_is_enabled(Debug, cds)) {
152 ResourceMark rm(THREAD);
153 log_debug(cds)(" calling %s", method->name_and_sig_as_C_string());
154 }
155 JavaValue result(T_VOID);
156 JavaCalls::call_special(&result, h_obj, klass,
157 method_name, method_sig, CHECK);
158 }
159 klass = klass->java_super();
160 }
161 }
162
163 void HeapShared::reset_archived_object_states(TRAPS) {
164 assert(DumpSharedSpaces, "dump-time only");
165 log_debug(cds)("Resetting platform loader");
166 reset_states(SystemDictionary::java_platform_loader(), THREAD);
167 log_debug(cds)("Resetting system loader");
168 reset_states(SystemDictionary::java_system_loader(), THREAD);
169 }
170
171 HeapShared::ArchivedObjectCache* HeapShared::_archived_object_cache = NULL;
172 oop HeapShared::find_archived_heap_object(oop obj) {
173 assert(DumpSharedSpaces, "dump-time only");
174 ArchivedObjectCache* cache = archived_object_cache();
175 oop* p = cache->get(obj);
176 if (p != NULL) {
177 return *p;
178 } else {
179 return NULL;
180 }
181 }
182
183 int HeapShared::append_root(oop obj) {
184 assert(DumpSharedSpaces, "dump-time only");
185
186 // No GC should happen since we aren't scanning _pending_roots.
187 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
188
189 if (_pending_roots == NULL) {
190 _pending_roots = new GrowableArrayCHeap<oop, mtClassShared>(500);
191 }
192
193 return _pending_roots->append(obj);
194 }
195
196 objArrayOop HeapShared::roots() {
197 if (DumpSharedSpaces) {
198 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
199 return _dumptime_roots;
200 } else {
201 assert(UseSharedSpaces, "must be");
202 objArrayOop roots = (objArrayOop)_runtime_roots.resolve();
203 assert(roots != NULL, "should have been initialized");
204 return roots;
205 }
206 }
207
208 void HeapShared::set_roots(narrowOop roots) {
209 assert(UseSharedSpaces, "runtime only");
210 assert(open_archive_heap_region_mapped(), "must be");
211 _runtime_roots_narrow = roots;
212 }
213
214 oop HeapShared::get_root(int index, bool clear) {
215 assert(index >= 0, "sanity");
216 if (DumpSharedSpaces) {
217 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
218 assert(_pending_roots != NULL, "sanity");
219 return _pending_roots->at(index);
220 } else {
221 assert(UseSharedSpaces, "must be");
222 assert(!_runtime_roots.is_empty(), "must have loaded shared heap");
223 oop result = roots()->obj_at(index);
224 if (clear) {
225 clear_root(index);
226 }
227 return result;
228 }
229 }
230
231 void HeapShared::clear_root(int index) {
232 assert(index >= 0, "sanity");
233 assert(UseSharedSpaces, "must be");
234 if (open_archive_heap_region_mapped()) {
235 if (log_is_enabled(Debug, cds, heap)) {
236 oop old = roots()->obj_at(index);
237 log_debug(cds, heap)("Clearing root %d: was " PTR_FORMAT, index, p2i(old));
238 }
239 roots()->obj_at_put(index, NULL);
240 }
241 }
242
243 oop HeapShared::archive_heap_object(oop obj, Thread* THREAD) {
244 assert(DumpSharedSpaces, "dump-time only");
245
246 oop ao = find_archived_heap_object(obj);
247 if (ao != NULL) {
248 // already archived
249 return ao;
250 }
251
252 int len = obj->size();
253 if (G1CollectedHeap::heap()->is_archive_alloc_too_large(len)) {
254 log_debug(cds, heap)("Cannot archive, object (" PTR_FORMAT ") is too large: " SIZE_FORMAT,
255 p2i(obj), (size_t)obj->size());
256 return NULL;
257 }
258
259 oop archived_oop = (oop)G1CollectedHeap::heap()->archive_mem_allocate(len);
260 if (archived_oop != NULL) {
261 Copy::aligned_disjoint_words(cast_from_oop<HeapWord*>(obj), cast_from_oop<HeapWord*>(archived_oop), len);
262 MetaspaceShared::relocate_klass_ptr(archived_oop);
263 // Reinitialize markword to remove age/marking/locking/etc.
264 //
265 // We need to retain the identity_hash, because it may have been used by some hashtables
266 // in the shared heap. This also has the side effect of pre-initializing the
267 // identity_hash for all shared objects, so they are less likely to be written
268 // into during run time, increasing the potential of memory sharing.
269 int hash_original = obj->identity_hash();
270 archived_oop->set_mark(markWord::prototype().copy_set_hash(hash_original));
271 assert(archived_oop->mark().is_unlocked(), "sanity");
272
273 DEBUG_ONLY(int hash_archived = archived_oop->identity_hash());
274 assert(hash_original == hash_archived, "Different hash codes: original %x, archived %x", hash_original, hash_archived);
275
276 ArchivedObjectCache* cache = archived_object_cache();
277 cache->put(obj, archived_oop);
278 if (log_is_enabled(Debug, cds, heap)) {
279 ResourceMark rm;
280 log_debug(cds, heap)("Archived heap object " PTR_FORMAT " ==> " PTR_FORMAT " : %s",
281 p2i(obj), p2i(archived_oop), obj->klass()->external_name());
282 }
283 } else {
284 log_error(cds, heap)(
285 "Cannot allocate space for object " PTR_FORMAT " in archived heap region",
286 p2i(obj));
287 vm_exit(1);
288 }
289 return archived_oop;
290 }
291
292 oop HeapShared::materialize_archived_object(narrowOop v) {
293 assert(archive_heap_region_fixed(),
294 "must be called after archive heap regions are fixed");
295 if (!CompressedOops::is_null(v)) {
296 oop obj = HeapShared::decode_from_archive(v);
297 return G1CollectedHeap::heap()->materialize_archived_object(obj);
298 }
299 return NULL;
300 }
301
302 void HeapShared::archive_klass_objects(Thread* THREAD) {
303 GrowableArray<Klass*>* klasses = MetaspaceShared::collected_klasses();
304 assert(klasses != NULL, "sanity");
305 for (int i = 0; i < klasses->length(); i++) {
306 Klass* k = klasses->at(i);
307
308 // archive mirror object
309 java_lang_Class::archive_mirror(k, CHECK);
310
311 // archive the resolved_referenes array
312 if (k->is_instance_klass()) {
313 InstanceKlass* ik = InstanceKlass::cast(k);
314 ik->constants()->archive_resolved_references(THREAD);
315 }
316 }
317 }
318
319 void HeapShared::run_full_gc_in_vm_thread() {
320 if (is_heap_object_archiving_allowed()) {
321 // Avoid fragmentation while archiving heap objects.
322 // We do this inside a safepoint, so that no further allocation can happen after GC
323 // has finished.
324 if (GCLocker::is_active()) {
325 // Just checking for safety ...
326 // This should not happen during -Xshare:dump. If you see this, probably the Java core lib
327 // has been modified such that JNI code is executed in some clean up threads after
328 // we have finished class loading.
329 log_warning(cds)("GC locker is held, unable to start extra compacting GC. This may produce suboptimal results.");
330 } else {
331 log_info(cds)("Run GC ...");
332 Universe::heap()->collect_as_vm_thread(GCCause::_archive_time_gc);
333 log_info(cds)("Run GC done");
334 }
335 }
336 }
337
338 // Returns an objArray that contains all the roots of the archived objects
339 void HeapShared::archive_java_heap_objects(GrowableArray<MemRegion> *closed,
340 GrowableArray<MemRegion> *open) {
341 if (!is_heap_object_archiving_allowed()) {
342 log_info(cds)(
343 "Archived java heap is not supported as UseG1GC, "
344 "UseCompressedOops and UseCompressedClassPointers are required."
345 "Current settings: UseG1GC=%s, UseCompressedOops=%s, UseCompressedClassPointers=%s.",
346 BOOL_TO_STR(UseG1GC), BOOL_TO_STR(UseCompressedOops),
347 BOOL_TO_STR(UseCompressedClassPointers));
348 return;
349 }
350
351 G1HeapVerifier::verify_ready_for_archiving();
352
353 {
354 NoSafepointVerifier nsv;
355
356 // Cache for recording where the archived objects are copied to
357 create_archived_object_cache();
358
359 log_info(cds)("Dumping objects to closed archive heap region ...");
360 copy_closed_archive_heap_objects(closed);
361
362 log_info(cds)("Dumping objects to open archive heap region ...");
363 copy_open_archive_heap_objects(open);
364
365 destroy_archived_object_cache();
366 }
367
368 G1HeapVerifier::verify_archive_regions();
369 }
370
371 void HeapShared::copy_closed_archive_heap_objects(
372 GrowableArray<MemRegion> * closed_archive) {
373 assert(is_heap_object_archiving_allowed(), "Cannot archive java heap objects");
374
375 Thread* THREAD = Thread::current();
376 G1CollectedHeap::heap()->begin_archive_alloc_range();
377
378 // Archive interned string objects
379 StringTable::write_to_archive(_dumped_interned_strings);
380
381 archive_object_subgraphs(closed_archive_subgraph_entry_fields,
382 num_closed_archive_subgraph_entry_fields,
383 true /* is_closed_archive */,
384 false /* is_full_module_graph */,
385 THREAD);
386
387 G1CollectedHeap::heap()->end_archive_alloc_range(closed_archive,
388 os::vm_allocation_granularity());
389 }
390
391 void HeapShared::copy_open_archive_heap_objects(
392 GrowableArray<MemRegion> * open_archive) {
393 assert(is_heap_object_archiving_allowed(), "Cannot archive java heap objects");
394
395 Thread* THREAD = Thread::current();
396 G1CollectedHeap::heap()->begin_archive_alloc_range(true /* open */);
397
398 java_lang_Class::archive_basic_type_mirrors(THREAD);
399
400 archive_klass_objects(THREAD);
401
402 archive_object_subgraphs(open_archive_subgraph_entry_fields,
403 num_open_archive_subgraph_entry_fields,
404 false /* is_closed_archive */,
405 false /* is_full_module_graph */,
406 THREAD);
407 if (MetaspaceShared::use_full_module_graph()) {
408 archive_object_subgraphs(fmg_open_archive_subgraph_entry_fields,
409 num_fmg_open_archive_subgraph_entry_fields,
410 false /* is_closed_archive */,
411 true /* is_full_module_graph */,
412 THREAD);
413 ClassLoaderDataShared::init_archived_oops();
414 }
415
416 copy_roots();
417
418 G1CollectedHeap::heap()->end_archive_alloc_range(open_archive,
419 os::vm_allocation_granularity());
420 }
421
422 // Copy _pending_archive_roots into an objArray
423 void HeapShared::copy_roots() {
424 int length = _pending_roots != NULL ? _pending_roots->length() : 0;
425 int size = objArrayOopDesc::object_size(length);
426 Klass *k = Universe::objectArrayKlassObj(); // already relocated to point to archived klass
427 HeapWord* mem = G1CollectedHeap::heap()->archive_mem_allocate(size);
428
429 memset(mem, 0, size * BytesPerWord); // Is this correct??
430 {
431 // This is copied from MemAllocator::finish
432 if (UseBiasedLocking) {
433 oopDesc::set_mark(mem, k->prototype_header());
434 } else {
435 oopDesc::set_mark(mem, markWord::prototype());
436 }
437 oopDesc::release_set_klass(mem, k);
438 }
439 {
440 // This is copied from ObjArrayAllocator::initialize
441 arrayOopDesc::set_length(mem, length);
442 }
443
444 _dumptime_roots = (objArrayOop)mem;
445 for (int i = 0; i < length; i++) {
446 _dumptime_roots->obj_at_put(i, _pending_roots->at(i));
447 }
448 log_info(cds)("archived obj roots[%d] = %d words, klass = %p, obj = %p", length, size, k, mem);
449 }
450
451 void HeapShared::init_narrow_oop_decoding(address base, int shift) {
452 _narrow_oop_base = base;
453 _narrow_oop_shift = shift;
454 }
455
456 //
457 // Subgraph archiving support
458 //
459 HeapShared::DumpTimeKlassSubGraphInfoTable* HeapShared::_dump_time_subgraph_info_table = NULL;
460 HeapShared::RunTimeKlassSubGraphInfoTable HeapShared::_run_time_subgraph_info_table;
461
462 // Get the subgraph_info for Klass k. A new subgraph_info is created if
463 // there is no existing one for k. The subgraph_info records the relocated
464 // Klass* of the original k.
465 KlassSubGraphInfo* HeapShared::init_subgraph_info(Klass* k, bool is_full_module_graph) {
466 assert(DumpSharedSpaces, "dump time only");
467 bool created;
468 Klass* relocated_k = MetaspaceShared::get_relocated_klass(k);
469 KlassSubGraphInfo* info =
470 _dump_time_subgraph_info_table->put_if_absent(relocated_k, KlassSubGraphInfo(relocated_k, is_full_module_graph),
471 &created);
472 assert(created, "must not initialize twice");
473 return info;
474 }
475
476 KlassSubGraphInfo* HeapShared::get_subgraph_info(Klass* k) {
477 assert(DumpSharedSpaces, "dump time only");
478 Klass* relocated_k = MetaspaceShared::get_relocated_klass(k);
479 KlassSubGraphInfo* info = _dump_time_subgraph_info_table->get(relocated_k);
480 assert(info != NULL, "must have been initialized");
481 return info;
482 }
483
484 // Add an entry field to the current KlassSubGraphInfo.
485 void KlassSubGraphInfo::add_subgraph_entry_field(
486 int static_field_offset, oop v, bool is_closed_archive) {
487 assert(DumpSharedSpaces, "dump time only");
488 if (_subgraph_entry_fields == NULL) {
489 _subgraph_entry_fields =
490 new(ResourceObj::C_HEAP, mtClass) GrowableArray<int>(10, mtClass);
491 }
492 _subgraph_entry_fields->append(static_field_offset);
493 _subgraph_entry_fields->append(HeapShared::append_root(v));
494 _subgraph_entry_fields->append(is_closed_archive ? 1 : 0);
495 }
496
497 // Add the Klass* for an object in the current KlassSubGraphInfo's subgraphs.
498 // Only objects of boot classes can be included in sub-graph.
499 void KlassSubGraphInfo::add_subgraph_object_klass(Klass* orig_k, Klass *relocated_k) {
500 assert(DumpSharedSpaces, "dump time only");
501 assert(relocated_k == MetaspaceShared::get_relocated_klass(orig_k),
502 "must be the relocated Klass in the shared space");
503
504 if (_subgraph_object_klasses == NULL) {
505 _subgraph_object_klasses =
506 new(ResourceObj::C_HEAP, mtClass) GrowableArray<Klass*>(50, mtClass);
507 }
508
509 assert(ArchiveBuilder::singleton()->is_in_buffer_space(relocated_k), "must be a shared class");
510
511 if (_k == relocated_k) {
512 // Don't add the Klass containing the sub-graph to it's own klass
513 // initialization list.
514 return;
515 }
516
517 if (relocated_k->is_instance_klass()) {
518 assert(InstanceKlass::cast(relocated_k)->is_shared_boot_class(),
519 "must be boot class");
520 // SystemDictionary::xxx_klass() are not updated, need to check
521 // the original Klass*
522 if (orig_k == SystemDictionary::String_klass() ||
523 orig_k == SystemDictionary::Object_klass()) {
524 // Initialized early during VM initialization. No need to be added
525 // to the sub-graph object class list.
526 return;
527 }
528 } else if (relocated_k->is_objArray_klass()) {
529 Klass* abk = ObjArrayKlass::cast(relocated_k)->bottom_klass();
530 if (abk->is_instance_klass()) {
531 assert(InstanceKlass::cast(abk)->is_shared_boot_class(),
532 "must be boot class");
533 }
534 if (relocated_k == Universe::objectArrayKlassObj()) {
535 // Initialized early during Universe::genesis. No need to be added
536 // to the list.
537 return;
538 }
539 } else {
540 assert(relocated_k->is_typeArray_klass(), "must be");
541 // Primitive type arrays are created early during Universe::genesis.
542 return;
543 }
544
545 if (log_is_enabled(Debug, cds, heap)) {
546 if (!_subgraph_object_klasses->contains(relocated_k)) {
547 ResourceMark rm;
548 log_debug(cds, heap)("Adding klass %s", orig_k->external_name());
549 }
550 }
551
552 _subgraph_object_klasses->append_if_missing(relocated_k);
553 _has_non_early_klasses |= is_non_early_klass(orig_k);
554 }
555
556 bool KlassSubGraphInfo::is_non_early_klass(Klass* k) {
557 if (k->is_objArray_klass()) {
558 k = ObjArrayKlass::cast(k)->bottom_klass();
559 }
560 if (k->is_instance_klass()) {
561 if (!SystemDictionaryShared::is_early_klass(InstanceKlass::cast(k))) {
562 ResourceMark rm;
563 log_info(cds, heap)("non-early: %s", k->external_name());
564 return true;
565 } else {
566 return false;
567 }
568 } else {
569 return false;
570 }
571 }
572
573 // Initialize an archived subgraph_info_record from the given KlassSubGraphInfo.
574 void ArchivedKlassSubGraphInfoRecord::init(KlassSubGraphInfo* info) {
575 _k = info->klass();
576 _entry_field_records = NULL;
577 _subgraph_object_klasses = NULL;
578 _is_full_module_graph = info->is_full_module_graph();
579 _has_non_early_klasses = info->has_non_early_klasses();
580
581 if (_has_non_early_klasses) {
582 ResourceMark rm;
583 log_info(cds, heap)(
584 "Subgraph of klass %s has non-early klasses and cannot be used when JVMTI ClassFileLoadHook is enabled",
585 _k->external_name());
586 }
587
588 // populate the entry fields
589 GrowableArray<int>* entry_fields = info->subgraph_entry_fields();
590 if (entry_fields != NULL) {
591 int num_entry_fields = entry_fields->length();
592 assert(num_entry_fields % 3 == 0, "sanity");
593 _entry_field_records =
594 MetaspaceShared::new_ro_array<int>(num_entry_fields);
595 for (int i = 0 ; i < num_entry_fields; i++) {
596 _entry_field_records->at_put(i, entry_fields->at(i));
597 }
598 }
599
600 // the Klasses of the objects in the sub-graphs
601 GrowableArray<Klass*>* subgraph_object_klasses = info->subgraph_object_klasses();
602 if (subgraph_object_klasses != NULL) {
603 int num_subgraphs_klasses = subgraph_object_klasses->length();
604 _subgraph_object_klasses =
605 MetaspaceShared::new_ro_array<Klass*>(num_subgraphs_klasses);
606 for (int i = 0; i < num_subgraphs_klasses; i++) {
607 Klass* subgraph_k = subgraph_object_klasses->at(i);
608 if (log_is_enabled(Info, cds, heap)) {
609 ResourceMark rm;
610 log_info(cds, heap)(
611 "Archived object klass %s (%2d) => %s",
612 _k->external_name(), i, subgraph_k->external_name());
613 }
614 _subgraph_object_klasses->at_put(i, subgraph_k);
615 ArchivePtrMarker::mark_pointer(_subgraph_object_klasses->adr_at(i));
616 }
617 }
618
619 ArchivePtrMarker::mark_pointer(&_k);
620 ArchivePtrMarker::mark_pointer(&_entry_field_records);
621 ArchivePtrMarker::mark_pointer(&_subgraph_object_klasses);
622 }
623
624 struct CopyKlassSubGraphInfoToArchive : StackObj {
625 CompactHashtableWriter* _writer;
626 CopyKlassSubGraphInfoToArchive(CompactHashtableWriter* writer) : _writer(writer) {}
627
628 bool do_entry(Klass* klass, KlassSubGraphInfo& info) {
629 if (info.subgraph_object_klasses() != NULL || info.subgraph_entry_fields() != NULL) {
630 ArchivedKlassSubGraphInfoRecord* record =
631 (ArchivedKlassSubGraphInfoRecord*)MetaspaceShared::read_only_space_alloc(sizeof(ArchivedKlassSubGraphInfoRecord));
632 record->init(&info);
633
634 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary(klass);
635 u4 delta = MetaspaceShared::object_delta_u4(record);
636 _writer->add(hash, delta);
637 }
638 return true; // keep on iterating
639 }
640 };
641
642 // Build the records of archived subgraph infos, which include:
643 // - Entry points to all subgraphs from the containing class mirror. The entry
644 // points are static fields in the mirror. For each entry point, the field
645 // offset, value and is_closed_archive flag are recorded in the sub-graph
646 // info. The value is stored back to the corresponding field at runtime.
647 // - A list of klasses that need to be loaded/initialized before archived
648 // java object sub-graph can be accessed at runtime.
649 void HeapShared::write_subgraph_info_table() {
650 // Allocate the contents of the hashtable(s) inside the RO region of the CDS archive.
651 DumpTimeKlassSubGraphInfoTable* d_table = _dump_time_subgraph_info_table;
652 CompactHashtableStats stats;
653
654 _run_time_subgraph_info_table.reset();
655
656 CompactHashtableWriter writer(d_table->_count, &stats);
657 CopyKlassSubGraphInfoToArchive copy(&writer);
658 d_table->iterate(©);
659
660 writer.dump(&_run_time_subgraph_info_table, "subgraphs");
661 }
662
663 void HeapShared::serialize_subgraph_info_table_header(SerializeClosure* soc) {
664 _run_time_subgraph_info_table.serialize_header(soc);
665 }
666
667 static void verify_the_heap(Klass* k, const char* which) {
668 if (VerifyArchivedFields) {
669 ResourceMark rm;
670 log_info(cds, heap)("Verify heap %s initializing static field(s) in %s",
671 which, k->external_name());
672 VM_Verify verify_op;
673 VMThread::execute(&verify_op);
674 #if 0
675 // For some reason, this causes jtreg to lock up with
676 // "jtreg -vmoptions:-XX:+VerifyArchivedFields HelloTest.java"
677 if (is_init_completed()) {
678 FlagSetting fs1(VerifyBeforeGC, true);
679 FlagSetting fs2(VerifyDuringGC, true);
680 FlagSetting fs3(VerifyAfterGC, true);
681 Universe::heap()->collect(GCCause::_java_lang_system_gc);
682 }
683 #endif
684 }
685 }
686
687 // Before GC can execute, we must ensure that all oops reachable from HeapShared::roots()
688 // have a valid klass. I.e., oopDesc::klass() must have already been resolved.
689 //
690 // Note: if a ArchivedKlassSubGraphInfoRecord contains non-early classes, and JVMTI
691 // ClassFileLoadHook is enabled, it's possible for this class to be dynamically replaced. In
692 // this case, we will not load the ArchivedKlassSubGraphInfoRecord and will clear its roots.
693 void HeapShared::resolve_classes(TRAPS) {
694 if (!is_mapped()) {
695 return; // nothing to do
696 }
697 resolve_classes_for_subgraphs(closed_archive_subgraph_entry_fields,
698 num_closed_archive_subgraph_entry_fields,
699 CHECK);
700 resolve_classes_for_subgraphs(open_archive_subgraph_entry_fields,
701 num_open_archive_subgraph_entry_fields,
702 CHECK);
703 resolve_classes_for_subgraphs(fmg_open_archive_subgraph_entry_fields,
704 num_fmg_open_archive_subgraph_entry_fields,
705 CHECK);
706 }
707
708 void HeapShared::resolve_classes_for_subgraphs(ArchivableStaticFieldInfo fields[],
709 int num, TRAPS) {
710 for (int i = 0; i < num; i++) {
711 ArchivableStaticFieldInfo* info = &fields[i];
712 TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name);
713 InstanceKlass* k = SystemDictionaryShared::find_builtin_class(klass_name);
714 assert(k != NULL && k->is_shared_boot_class(), "sanity");
715 resolve_classes_for_subgraph_of(k, CHECK);
716 }
717 }
718
719 void HeapShared::resolve_classes_for_subgraph_of(Klass* k, TRAPS) {
720 const ArchivedKlassSubGraphInfoRecord* record = resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/false, THREAD);
721 if (HAS_PENDING_EXCEPTION) {
722 CLEAR_PENDING_EXCEPTION;
723 }
724 if (record == NULL) {
725 clear_archived_roots_of(k);
726 }
727 }
728
729 void HeapShared::initialize_from_archived_subgraph(Klass* k, TRAPS) {
730 if (!is_mapped()) {
731 return; // nothing to do
732 }
733
734 const ArchivedKlassSubGraphInfoRecord* record =
735 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/true, THREAD);
736
737 if (HAS_PENDING_EXCEPTION) {
738 CLEAR_PENDING_EXCEPTION;
739 // None of the field value will be set if there was an exception when initializing the classes.
740 // The java code will not see any of the archived objects in the
741 // subgraphs referenced from k in this case.
742 return;
743 }
744
745 if (record != NULL) {
746 init_archived_fields_for(k, record, THREAD);
747 }
748 }
749
750 const ArchivedKlassSubGraphInfoRecord*
751 HeapShared::resolve_or_init_classes_for_subgraph_of(Klass* k, bool do_init, TRAPS) {
752 assert(!DumpSharedSpaces, "Should not be called with DumpSharedSpaces");
753
754 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary(k);
755 const ArchivedKlassSubGraphInfoRecord* record = _run_time_subgraph_info_table.lookup(k, hash, 0);
756
757 // Initialize from archived data. Currently this is done only
758 // during VM initialization time. No lock is needed.
759 if (record != NULL) {
760 if (record->is_full_module_graph() && !MetaspaceShared::use_full_module_graph()) {
761 if (log_is_enabled(Info, cds, heap)) {
762 ResourceMark rm;
763 log_info(cds, heap)("subgraph %s cannot be used because full module graph is disabled",
764 k->external_name());
765 }
766 return NULL;
767 }
768
769 if (record->has_non_early_klasses() && JvmtiExport::should_post_class_file_load_hook()) {
770 if (log_is_enabled(Info, cds, heap)) {
771 ResourceMark rm;
772 log_info(cds, heap)("subgraph %s cannot be used because JVMTI ClassFileLoadHook is enabled",
773 k->external_name());
774 }
775 return NULL;
776 }
777
778 resolve_or_init(k, do_init, CHECK_NULL);
779
780 // Load/link/initialize the klasses of the objects in the subgraph.
781 // NULL class loader is used.
782 Array<Klass*>* klasses = record->subgraph_object_klasses();
783 if (klasses != NULL) {
784 for (int i = 0; i < klasses->length(); i++) {
785 resolve_or_init(klasses->at(i), do_init, CHECK_NULL);
786 }
787 }
788 }
789
790 return record;
791 }
792
793 void HeapShared::resolve_or_init(Klass* k, bool do_init, TRAPS) {
794 if (!do_init) {
795 if (k->class_loader_data() == NULL) {
796 Klass* resolved_k = SystemDictionary::resolve_or_null(k->name(), CHECK);
797 assert(resolved_k == k, "classes used by archived heap must not be replaced by JVMTI ClassFileLoadHook");
798 }
799 } else {
800 assert(k->class_loader_data() != NULL, "must have been resolved by HeapShared::resolve_classes");
801 if (k->is_instance_klass()) {
802 InstanceKlass* ik = InstanceKlass::cast(k);
803 ik->initialize(CHECK);
804 } else if (k->is_objArray_klass()) {
805 ObjArrayKlass* oak = ObjArrayKlass::cast(k);
806 oak->initialize(CHECK);
807 }
808 }
809 }
810
811 void HeapShared::init_archived_fields_for(Klass* k, const ArchivedKlassSubGraphInfoRecord* record, TRAPS) {
812 verify_the_heap(k, "before");
813
814 // Load the subgraph entry fields from the record and store them back to
815 // the corresponding fields within the mirror.
816 oop m = k->java_mirror();
817 Array<int>* entry_field_records = record->entry_field_records();
818 if (entry_field_records != NULL) {
819 int efr_len = entry_field_records->length();
820 assert(efr_len % 3 == 0, "sanity");
821 for (int i = 0; i < efr_len; i += 3) {
822 int field_offset = entry_field_records->at(i);
823 int root_index = entry_field_records->at(i+1);
824 int is_closed_archive = entry_field_records->at(i+2);
825 oop v = get_root(root_index, /*clear=*/true);
826 m->obj_field_put(field_offset, v);
827 log_debug(cds, heap)(" " PTR_FORMAT " init field @ %2d = " PTR_FORMAT, p2i(k), field_offset, p2i(v));
828 }
829
830 // Done. Java code can see the archived sub-graphs referenced from k's
831 // mirror after this point.
832 if (log_is_enabled(Info, cds, heap)) {
833 ResourceMark rm;
834 log_info(cds, heap)("initialize_from_archived_subgraph %s " PTR_FORMAT "%s",
835 k->external_name(), p2i(k), JvmtiExport::is_early_phase() ? " (early)" : "");
836 }
837 }
838
839 verify_the_heap(k, "after ");
840 }
841
842 void HeapShared::clear_archived_roots_of(Klass* k) {
843 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary(k);
844 const ArchivedKlassSubGraphInfoRecord* record = _run_time_subgraph_info_table.lookup(k, hash, 0);
845 if (record != NULL) {
846 Array<int>* entry_field_records = record->entry_field_records();
847 if (entry_field_records != NULL) {
848 int efr_len = entry_field_records->length();
849 assert(efr_len % 3 == 0, "sanity");
850 for (int i = 0; i < efr_len; i += 3) {
851 int root_index = entry_field_records->at(i+1);
852 clear_root(root_index);
853 }
854 }
855 }
856 }
857
858 class WalkOopAndArchiveClosure: public BasicOopIterateClosure {
859 int _level;
860 bool _is_closed_archive;
861 bool _record_klasses_only;
862 KlassSubGraphInfo* _subgraph_info;
863 oop _orig_referencing_obj;
864 oop _archived_referencing_obj;
865 Thread* _thread;
866 public:
867 WalkOopAndArchiveClosure(int level,
868 bool is_closed_archive,
869 bool record_klasses_only,
870 KlassSubGraphInfo* subgraph_info,
871 oop orig, oop archived, TRAPS) :
872 _level(level), _is_closed_archive(is_closed_archive),
873 _record_klasses_only(record_klasses_only),
874 _subgraph_info(subgraph_info),
875 _orig_referencing_obj(orig), _archived_referencing_obj(archived),
876 _thread(THREAD) {}
877 void do_oop(narrowOop *p) { WalkOopAndArchiveClosure::do_oop_work(p); }
878 void do_oop( oop *p) { WalkOopAndArchiveClosure::do_oop_work(p); }
879
880 protected:
881 template <class T> void do_oop_work(T *p) {
882 oop obj = RawAccess<>::oop_load(p);
883 if (!CompressedOops::is_null(obj)) {
884 assert(!HeapShared::is_archived_object(obj),
885 "original objects must not point to archived objects");
886
887 size_t field_delta = pointer_delta(p, _orig_referencing_obj, sizeof(char));
888 T* new_p = (T*)(cast_from_oop<address>(_archived_referencing_obj) + field_delta);
889 Thread* THREAD = _thread;
890
891 if (!_record_klasses_only && log_is_enabled(Debug, cds, heap)) {
892 ResourceMark rm;
893 log_debug(cds, heap)("(%d) %s[" SIZE_FORMAT "] ==> " PTR_FORMAT " size %d %s", _level,
894 _orig_referencing_obj->klass()->external_name(), field_delta,
895 p2i(obj), obj->size() * HeapWordSize, obj->klass()->external_name());
896 LogTarget(Trace, cds, heap) log;
897 LogStream out(log);
898 obj->print_on(&out);
899 }
900
901 oop archived = HeapShared::archive_reachable_objects_from(
902 _level + 1, _subgraph_info, obj, _is_closed_archive, THREAD);
903 assert(archived != NULL, "VM should have exited with unarchivable objects for _level > 1");
904 assert(HeapShared::is_archived_object(archived), "must be");
905
906 if (!_record_klasses_only) {
907 // Update the reference in the archived copy of the referencing object.
908 log_debug(cds, heap)("(%d) updating oop @[" PTR_FORMAT "] " PTR_FORMAT " ==> " PTR_FORMAT,
909 _level, p2i(new_p), p2i(obj), p2i(archived));
910 RawAccess<IS_NOT_NULL>::oop_store(new_p, archived);
911 }
912 }
913 }
914 };
915
916 void HeapShared::check_closed_archive_heap_region_object(InstanceKlass* k,
917 Thread* THREAD) {
918 // Check fields in the object
919 for (JavaFieldStream fs(k); !fs.done(); fs.next()) {
920 if (!fs.access_flags().is_static()) {
921 BasicType ft = fs.field_descriptor().field_type();
922 if (!fs.access_flags().is_final() && is_reference_type(ft)) {
923 ResourceMark rm(THREAD);
924 log_warning(cds, heap)(
925 "Please check reference field in %s instance in closed archive heap region: %s %s",
926 k->external_name(), (fs.name())->as_C_string(),
927 (fs.signature())->as_C_string());
928 }
929 }
930 }
931 }
932
933 void HeapShared::check_module_oop(oop orig_module_obj) {
934 assert(DumpSharedSpaces, "must be");
935 assert(java_lang_Module::is_instance(orig_module_obj), "must be");
936 ModuleEntry* orig_module_ent = java_lang_Module::module_entry_raw(orig_module_obj);
937 if (orig_module_ent == NULL) {
938 // These special Module objects are created in Java code. They are not
939 // defined via Modules::define_module(), so they don't have a ModuleEntry:
940 // java.lang.Module::ALL_UNNAMED_MODULE
941 // java.lang.Module::EVERYONE_MODULE
942 // jdk.internal.loader.ClassLoaders$BootClassLoader::unnamedModule
943 assert(java_lang_Module::name(orig_module_obj) == NULL, "must be unnamed");
944 log_info(cds, heap)("Module oop with No ModuleEntry* @[" PTR_FORMAT "]", p2i(orig_module_obj));
945 } else {
946 ClassLoaderData* loader_data = orig_module_ent->loader_data();
947 assert(loader_data->is_builtin_class_loader_data(), "must be");
948 }
949 }
950
951
952 // (1) If orig_obj has not been archived yet, archive it.
953 // (2) If orig_obj has not been seen yet (since start_recording_subgraph() was called),
954 // trace all objects that are reachable from it, and make sure these objects are archived.
955 // (3) Record the klasses of all orig_obj and all reachable objects.
956 oop HeapShared::archive_reachable_objects_from(int level,
957 KlassSubGraphInfo* subgraph_info,
958 oop orig_obj,
959 bool is_closed_archive,
960 TRAPS) {
961 assert(orig_obj != NULL, "must be");
962 assert(!is_archived_object(orig_obj), "sanity");
963
964 if (!JavaClasses::is_supported_for_archiving(orig_obj)) {
965 // This object has injected fields that cannot be supported easily, so we disallow them for now.
966 // If you get an error here, you probably made a change in the JDK library that has added
967 // these objects that are referenced (directly or indirectly) by static fields.
968 ResourceMark rm;
969 log_error(cds, heap)("Cannot archive object of class %s", orig_obj->klass()->external_name());
970 vm_exit(1);
971 }
972
973 // java.lang.Class instances cannot be included in an archived object sub-graph. We only support
974 // them as Klass::_archived_mirror because they need to be specially restored at run time.
975 //
976 // If you get an error here, you probably made a change in the JDK library that has added a Class
977 // object that is referenced (directly or indirectly) by static fields.
978 if (java_lang_Class::is_instance(orig_obj)) {
979 log_error(cds, heap)("(%d) Unknown java.lang.Class object is in the archived sub-graph", level);
980 vm_exit(1);
981 }
982
983 oop archived_obj = find_archived_heap_object(orig_obj);
984 if (java_lang_String::is_instance(orig_obj) && archived_obj != NULL) {
985 // To save time, don't walk strings that are already archived. They just contain
986 // pointers to a type array, whose klass doesn't need to be recorded.
987 return archived_obj;
988 }
989
990 if (has_been_seen_during_subgraph_recording(orig_obj)) {
991 // orig_obj has already been archived and traced. Nothing more to do.
992 return archived_obj;
993 } else {
994 set_has_been_seen_during_subgraph_recording(orig_obj);
995 }
996
997 bool record_klasses_only = (archived_obj != NULL);
998 if (archived_obj == NULL) {
999 ++_num_new_archived_objs;
1000 archived_obj = archive_heap_object(orig_obj, THREAD);
1001 if (archived_obj == NULL) {
1002 // Skip archiving the sub-graph referenced from the current entry field.
1003 ResourceMark rm;
1004 log_error(cds, heap)(
1005 "Cannot archive the sub-graph referenced from %s object ("
1006 PTR_FORMAT ") size %d, skipped.",
1007 orig_obj->klass()->external_name(), p2i(orig_obj), orig_obj->size() * HeapWordSize);
1008 if (level == 1) {
1009 // Don't archive a subgraph root that's too big. For archives static fields, that's OK
1010 // as the Java code will take care of initializing this field dynamically.
1011 return NULL;
1012 } else {
1013 // We don't know how to handle an object that has been archived, but some of its reachable
1014 // objects cannot be archived. Bail out for now. We might need to fix this in the future if
1015 // we have a real use case.
1016 vm_exit(1);
1017 }
1018 }
1019
1020 if (java_lang_Module::is_instance(orig_obj)) {
1021 check_module_oop(orig_obj);
1022 java_lang_Module::set_module_entry(archived_obj, NULL);
1023 java_lang_Module::set_loader(archived_obj, NULL);
1024 } else if (java_lang_ClassLoader::is_instance(orig_obj)) {
1025 // class_data will be restored explicitly at run time.
1026 guarantee(orig_obj == SystemDictionary::java_platform_loader() ||
1027 orig_obj == SystemDictionary::java_system_loader() ||
1028 java_lang_ClassLoader::loader_data_raw(orig_obj) == NULL, "must be");
1029 java_lang_ClassLoader::release_set_loader_data(archived_obj, NULL);
1030 }
1031 }
1032
1033 assert(archived_obj != NULL, "must be");
1034 Klass *orig_k = orig_obj->klass();
1035 Klass *relocated_k = archived_obj->klass();
1036 subgraph_info->add_subgraph_object_klass(orig_k, relocated_k);
1037
1038 WalkOopAndArchiveClosure walker(level, is_closed_archive, record_klasses_only,
1039 subgraph_info, orig_obj, archived_obj, THREAD);
1040 orig_obj->oop_iterate(&walker);
1041 if (is_closed_archive && orig_k->is_instance_klass()) {
1042 check_closed_archive_heap_region_object(InstanceKlass::cast(orig_k), THREAD);
1043 }
1044 return archived_obj;
1045 }
1046
1047 //
1048 // Start from the given static field in a java mirror and archive the
1049 // complete sub-graph of java heap objects that are reached directly
1050 // or indirectly from the starting object by following references.
1051 // Sub-graph archiving restrictions (current):
1052 //
1053 // - All classes of objects in the archived sub-graph (including the
1054 // entry class) must be boot class only.
1055 // - No java.lang.Class instance (java mirror) can be included inside
1056 // an archived sub-graph. Mirror can only be the sub-graph entry object.
1057 //
1058 // The Java heap object sub-graph archiving process (see
1059 // WalkOopAndArchiveClosure):
1060 //
1061 // 1) Java object sub-graph archiving starts from a given static field
1062 // within a Class instance (java mirror). If the static field is a
1063 // refererence field and points to a non-null java object, proceed to
1064 // the next step.
1065 //
1066 // 2) Archives the referenced java object. If an archived copy of the
1067 // current object already exists, updates the pointer in the archived
1068 // copy of the referencing object to point to the current archived object.
1069 // Otherwise, proceed to the next step.
1070 //
1071 // 3) Follows all references within the current java object and recursively
1072 // archive the sub-graph of objects starting from each reference.
1073 //
1074 // 4) Updates the pointer in the archived copy of referencing object to
1075 // point to the current archived object.
1076 //
1077 // 5) The Klass of the current java object is added to the list of Klasses
1078 // for loading and initialzing before any object in the archived graph can
1079 // be accessed at runtime.
1080 //
1081 void HeapShared::archive_reachable_objects_from_static_field(InstanceKlass *k,
1082 const char* klass_name,
1083 int field_offset,
1084 const char* field_name,
1085 bool is_closed_archive,
1086 TRAPS) {
1087 assert(DumpSharedSpaces, "dump time only");
1088 assert(k->is_shared_boot_class(), "must be boot class");
1089
1090 oop m = k->java_mirror();
1091
1092 KlassSubGraphInfo* subgraph_info = get_subgraph_info(k);
1093 oop f = m->obj_field(field_offset);
1094
1095 log_debug(cds, heap)("Start archiving from: %s::%s (" PTR_FORMAT ")", klass_name, field_name, p2i(f));
1096
1097 if (!CompressedOops::is_null(f)) {
1098 if (log_is_enabled(Trace, cds, heap)) {
1099 LogTarget(Trace, cds, heap) log;
1100 LogStream out(log);
1101 f->print_on(&out);
1102 }
1103
1104 oop af = archive_reachable_objects_from(1, subgraph_info, f,
1105 is_closed_archive, CHECK);
1106
1107 if (af == NULL) {
1108 log_error(cds, heap)("Archiving failed %s::%s (some reachable objects cannot be archived)",
1109 klass_name, field_name);
1110 } else {
1111 // Note: the field value is not preserved in the archived mirror.
1112 // Record the field as a new subGraph entry point. The recorded
1113 // information is restored from the archive at runtime.
1114 subgraph_info->add_subgraph_entry_field(field_offset, af, is_closed_archive);
1115 log_info(cds, heap)("Archived field %s::%s => " PTR_FORMAT, klass_name, field_name, p2i(af));
1116 }
1117 } else {
1118 // The field contains null, we still need to record the entry point,
1119 // so it can be restored at runtime.
1120 subgraph_info->add_subgraph_entry_field(field_offset, NULL, false);
1121 }
1122 }
1123
1124 #ifndef PRODUCT
1125 class VerifySharedOopClosure: public BasicOopIterateClosure {
1126 private:
1127 bool _is_archived;
1128
1129 public:
1130 VerifySharedOopClosure(bool is_archived) : _is_archived(is_archived) {}
1131
1132 void do_oop(narrowOop *p) { VerifySharedOopClosure::do_oop_work(p); }
1133 void do_oop( oop *p) { VerifySharedOopClosure::do_oop_work(p); }
1134
1135 protected:
1136 template <class T> void do_oop_work(T *p) {
1137 oop obj = RawAccess<>::oop_load(p);
1138 if (!CompressedOops::is_null(obj)) {
1139 HeapShared::verify_reachable_objects_from(obj, _is_archived);
1140 }
1141 }
1142 };
1143
1144 void HeapShared::verify_subgraph_from_static_field(InstanceKlass* k, int field_offset) {
1145 assert(DumpSharedSpaces, "dump time only");
1146 assert(k->is_shared_boot_class(), "must be boot class");
1147
1148 oop m = k->java_mirror();
1149 oop f = m->obj_field(field_offset);
1150 if (!CompressedOops::is_null(f)) {
1151 verify_subgraph_from(f);
1152 }
1153 }
1154
1155 void HeapShared::verify_subgraph_from(oop orig_obj) {
1156 oop archived_obj = find_archived_heap_object(orig_obj);
1157 if (archived_obj == NULL) {
1158 // It's OK for the root of a subgraph to be not archived. See comments in
1159 // archive_reachable_objects_from().
1160 return;
1161 }
1162
1163 // Verify that all objects reachable from orig_obj are archived.
1164 init_seen_objects_table();
1165 verify_reachable_objects_from(orig_obj, false);
1166 delete_seen_objects_table();
1167
1168 // Note: we could also verify that all objects reachable from the archived
1169 // copy of orig_obj can only point to archived objects, with:
1170 // init_seen_objects_table();
1171 // verify_reachable_objects_from(archived_obj, true);
1172 // init_seen_objects_table();
1173 // but that's already done in G1HeapVerifier::verify_archive_regions so we
1174 // won't do it here.
1175 }
1176
1177 void HeapShared::verify_reachable_objects_from(oop obj, bool is_archived) {
1178 _num_total_verifications ++;
1179 if (!has_been_seen_during_subgraph_recording(obj)) {
1180 set_has_been_seen_during_subgraph_recording(obj);
1181
1182 if (is_archived) {
1183 assert(is_archived_object(obj), "must be");
1184 assert(find_archived_heap_object(obj) == NULL, "must be");
1185 } else {
1186 assert(!is_archived_object(obj), "must be");
1187 assert(find_archived_heap_object(obj) != NULL, "must be");
1188 }
1189
1190 VerifySharedOopClosure walker(is_archived);
1191 obj->oop_iterate(&walker);
1192 }
1193 }
1194 #endif
1195
1196 HeapShared::SeenObjectsTable* HeapShared::_seen_objects_table = NULL;
1197 int HeapShared::_num_new_walked_objs;
1198 int HeapShared::_num_new_archived_objs;
1199 int HeapShared::_num_old_recorded_klasses;
1200
1201 int HeapShared::_num_total_subgraph_recordings = 0;
1202 int HeapShared::_num_total_walked_objs = 0;
1203 int HeapShared::_num_total_archived_objs = 0;
1204 int HeapShared::_num_total_recorded_klasses = 0;
1205 int HeapShared::_num_total_verifications = 0;
1206
1207 bool HeapShared::has_been_seen_during_subgraph_recording(oop obj) {
1208 return _seen_objects_table->get(obj) != NULL;
1209 }
1210
1211 void HeapShared::set_has_been_seen_during_subgraph_recording(oop obj) {
1212 assert(!has_been_seen_during_subgraph_recording(obj), "sanity");
1213 _seen_objects_table->put(obj, true);
1214 ++ _num_new_walked_objs;
1215 }
1216
1217 void HeapShared::start_recording_subgraph(InstanceKlass *k, const char* class_name, bool is_full_module_graph) {
1218 log_info(cds, heap)("Start recording subgraph(s) for archived fields in %s", class_name);
1219 init_subgraph_info(k, is_full_module_graph);
1220 init_seen_objects_table();
1221 _num_new_walked_objs = 0;
1222 _num_new_archived_objs = 0;
1223 _num_old_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses();
1224 }
1225
1226 void HeapShared::done_recording_subgraph(InstanceKlass *k, const char* class_name) {
1227 int num_new_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses() -
1228 _num_old_recorded_klasses;
1229 log_info(cds, heap)("Done recording subgraph(s) for archived fields in %s: "
1230 "walked %d objs, archived %d new objs, recorded %d classes",
1231 class_name, _num_new_walked_objs, _num_new_archived_objs,
1232 num_new_recorded_klasses);
1233
1234 delete_seen_objects_table();
1235
1236 _num_total_subgraph_recordings ++;
1237 _num_total_walked_objs += _num_new_walked_objs;
1238 _num_total_archived_objs += _num_new_archived_objs;
1239 _num_total_recorded_klasses += num_new_recorded_klasses;
1240 }
1241
1242 class ArchivableStaticFieldFinder: public FieldClosure {
1243 InstanceKlass* _ik;
1244 Symbol* _field_name;
1245 bool _found;
1246 int _offset;
1247 public:
1248 ArchivableStaticFieldFinder(InstanceKlass* ik, Symbol* field_name) :
1249 _ik(ik), _field_name(field_name), _found(false), _offset(-1) {}
1250
1251 virtual void do_field(fieldDescriptor* fd) {
1252 if (fd->name() == _field_name) {
1253 assert(!_found, "fields cannot be overloaded");
1254 assert(is_reference_type(fd->field_type()), "can archive only fields that are references");
1255 _found = true;
1256 _offset = fd->offset();
1257 }
1258 }
1259 bool found() { return _found; }
1260 int offset() { return _offset; }
1261 };
1262
1263 void HeapShared::init_subgraph_entry_fields(ArchivableStaticFieldInfo fields[],
1264 int num, Thread* THREAD) {
1265 for (int i = 0; i < num; i++) {
1266 ArchivableStaticFieldInfo* info = &fields[i];
1267 TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name);
1268 TempNewSymbol field_name = SymbolTable::new_symbol(info->field_name);
1269
1270 Klass* k = SystemDictionary::resolve_or_null(klass_name, THREAD);
1271 assert(k != NULL && !HAS_PENDING_EXCEPTION, "class must exist");
1272 InstanceKlass* ik = InstanceKlass::cast(k);
1273 assert(InstanceKlass::cast(ik)->is_shared_boot_class(),
1274 "Only support boot classes");
1275 ik->initialize(THREAD);
1276 guarantee(!HAS_PENDING_EXCEPTION, "exception in initialize");
1277
1278 ArchivableStaticFieldFinder finder(ik, field_name);
1279 ik->do_local_static_fields(&finder);
1280 assert(finder.found(), "field must exist");
1281
1282 info->klass = ik;
1283 info->offset = finder.offset();
1284 }
1285 }
1286
1287 void HeapShared::init_subgraph_entry_fields(Thread* THREAD) {
1288 _dump_time_subgraph_info_table = new (ResourceObj::C_HEAP, mtClass)DumpTimeKlassSubGraphInfoTable();
1289
1290 init_subgraph_entry_fields(closed_archive_subgraph_entry_fields,
1291 num_closed_archive_subgraph_entry_fields,
1292 THREAD);
1293 init_subgraph_entry_fields(open_archive_subgraph_entry_fields,
1294 num_open_archive_subgraph_entry_fields,
1295 THREAD);
1296 if (MetaspaceShared::use_full_module_graph()) {
1297 init_subgraph_entry_fields(fmg_open_archive_subgraph_entry_fields,
1298 num_fmg_open_archive_subgraph_entry_fields,
1299 THREAD);
1300 }
1301 }
1302
1303 void HeapShared::init_for_dumping(Thread* THREAD) {
1304 _dumped_interned_strings = new (ResourceObj::C_HEAP, mtClass)DumpedInternedStrings();
1305 init_subgraph_entry_fields(THREAD);
1306 }
1307
1308 void HeapShared::archive_object_subgraphs(ArchivableStaticFieldInfo fields[],
1309 int num, bool is_closed_archive,
1310 bool is_full_module_graph,
1311 Thread* THREAD) {
1312 _num_total_subgraph_recordings = 0;
1313 _num_total_walked_objs = 0;
1314 _num_total_archived_objs = 0;
1315 _num_total_recorded_klasses = 0;
1316 _num_total_verifications = 0;
1317
1318 // For each class X that has one or more archived fields:
1319 // [1] Dump the subgraph of each archived field
1320 // [2] Create a list of all the class of the objects that can be reached
1321 // by any of these static fields.
1322 // At runtime, these classes are initialized before X's archived fields
1323 // are restored by HeapShared::initialize_from_archived_subgraph().
1324 int i;
1325 for (i = 0; i < num; ) {
1326 ArchivableStaticFieldInfo* info = &fields[i];
1327 const char* klass_name = info->klass_name;
1328 start_recording_subgraph(info->klass, klass_name, is_full_module_graph);
1329
1330 // If you have specified consecutive fields of the same klass in
1331 // fields[], these will be archived in the same
1332 // {start_recording_subgraph ... done_recording_subgraph} pass to
1333 // save time.
1334 for (; i < num; i++) {
1335 ArchivableStaticFieldInfo* f = &fields[i];
1336 if (f->klass_name != klass_name) {
1337 break;
1338 }
1339
1340 archive_reachable_objects_from_static_field(f->klass, f->klass_name,
1341 f->offset, f->field_name,
1342 is_closed_archive, CHECK);
1343 }
1344 done_recording_subgraph(info->klass, klass_name);
1345 }
1346
1347 log_info(cds, heap)("Archived subgraph records in %s archive heap region = %d",
1348 is_closed_archive ? "closed" : "open",
1349 _num_total_subgraph_recordings);
1350 log_info(cds, heap)(" Walked %d objects", _num_total_walked_objs);
1351 log_info(cds, heap)(" Archived %d objects", _num_total_archived_objs);
1352 log_info(cds, heap)(" Recorded %d klasses", _num_total_recorded_klasses);
1353
1354 #ifndef PRODUCT
1355 for (int i = 0; i < num; i++) {
1356 ArchivableStaticFieldInfo* f = &fields[i];
1357 verify_subgraph_from_static_field(f->klass, f->offset);
1358 }
1359 log_info(cds, heap)(" Verified %d references", _num_total_verifications);
1360 #endif
1361 }
1362
1363 // Not all the strings in the global StringTable are dumped into the archive, because
1364 // some of those strings may be only referenced by classes that are excluded from
1365 // the archive. We need to explicitly mark the strings that are:
1366 // [1] used by classes that WILL be archived;
1367 // [2] included in the SharedArchiveConfigFile.
1368 void HeapShared::add_to_dumped_interned_strings(oop string) {
1369 assert_at_safepoint(); // DumpedInternedStrings uses raw oops
1370 bool created;
1371 _dumped_interned_strings->put_if_absent(string, true, &created);
1372 }
1373
1374 // At dump-time, find the location of all the non-null oop pointers in an archived heap
1375 // region. This way we can quickly relocate all the pointers without using
1376 // BasicOopIterateClosure at runtime.
1377 class FindEmbeddedNonNullPointers: public BasicOopIterateClosure {
1378 narrowOop* _start;
1379 BitMap *_oopmap;
1380 int _num_total_oops;
1381 int _num_null_oops;
1382 public:
1383 FindEmbeddedNonNullPointers(narrowOop* start, BitMap* oopmap)
1384 : _start(start), _oopmap(oopmap), _num_total_oops(0), _num_null_oops(0) {}
1385
1386 virtual bool should_verify_oops(void) {
1387 return false;
1388 }
1389 virtual void do_oop(narrowOop* p) {
1390 _num_total_oops ++;
1391 narrowOop v = *p;
1392 if (!CompressedOops::is_null(v)) {
1393 size_t idx = p - _start;
1394 _oopmap->set_bit(idx);
1395 } else {
1396 _num_null_oops ++;
1397 }
1398 }
1399 virtual void do_oop(oop *p) {
1400 ShouldNotReachHere();
1401 }
1402 int num_total_oops() const { return _num_total_oops; }
1403 int num_null_oops() const { return _num_null_oops; }
1404 };
1405
1406 ResourceBitMap HeapShared::calculate_oopmap(MemRegion region) {
1407 assert(UseCompressedOops, "must be");
1408 size_t num_bits = region.byte_size() / sizeof(narrowOop);
1409 ResourceBitMap oopmap(num_bits);
1410
1411 HeapWord* p = region.start();
1412 HeapWord* end = region.end();
1413 FindEmbeddedNonNullPointers finder((narrowOop*)p, &oopmap);
1414
1415 int num_objs = 0;
1416 while (p < end) {
1417 oop o = (oop)p;
1418 o->oop_iterate(&finder);
1419 p += o->size();
1420 ++ num_objs;
1421 }
1422
1423 log_info(cds, heap)("calculate_oopmap: objects = %6d, embedded oops = %7d, nulls = %7d",
1424 num_objs, finder.num_total_oops(), finder.num_null_oops());
1425 return oopmap;
1426 }
1427
1428 // Patch all the embedded oop pointers inside an archived heap region,
1429 // to be consistent with the runtime oop encoding.
1430 class PatchEmbeddedPointers: public BitMapClosure {
1431 narrowOop* _start;
1432
1433 public:
1434 PatchEmbeddedPointers(narrowOop* start) : _start(start) {}
1435
1436 bool do_bit(size_t offset) {
1437 narrowOop* p = _start + offset;
1438 narrowOop v = *p;
1439 assert(!CompressedOops::is_null(v), "null oops should have been filtered out at dump time");
1440 oop o = HeapShared::decode_from_archive(v);
1441 RawAccess<IS_NOT_NULL>::oop_store(p, o);
1442 return true;
1443 }
1444 };
1445
1446 void HeapShared::patch_archived_heap_embedded_pointers(MemRegion region, address oopmap,
1447 size_t oopmap_size_in_bits) {
1448 BitMapView bm((BitMap::bm_word_t*)oopmap, oopmap_size_in_bits);
1449
1450 #ifndef PRODUCT
1451 ResourceMark rm;
1452 ResourceBitMap checkBm = calculate_oopmap(region);
1453 assert(bm.is_same(checkBm), "sanity");
1454 #endif
1455
1456 PatchEmbeddedPointers patcher((narrowOop*)region.start());
1457 bm.iterate(&patcher);
1458 }
1459
1460 #endif // INCLUDE_CDS_JAVA_HEAP