1 /*
2 * Copyright (c) 2018, 2021, 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 "cds/archiveBuilder.hpp"
27 #include "cds/archiveUtils.hpp"
28 #include "cds/filemap.hpp"
29 #include "cds/heapShared.inline.hpp"
30 #include "cds/metaspaceShared.hpp"
31 #include "classfile/classLoaderData.hpp"
32 #include "classfile/classLoaderDataShared.hpp"
33 #include "classfile/javaClasses.inline.hpp"
34 #include "classfile/moduleEntry.hpp"
35 #include "classfile/stringTable.hpp"
36 #include "classfile/symbolTable.hpp"
37 #include "classfile/systemDictionary.hpp"
38 #include "classfile/systemDictionaryShared.hpp"
39 #include "classfile/vmClasses.hpp"
40 #include "classfile/vmSymbols.hpp"
41 #include "gc/shared/gcLocker.hpp"
42 #include "gc/shared/gcVMOperations.hpp"
43 #include "logging/log.hpp"
44 #include "logging/logMessage.hpp"
45 #include "logging/logStream.hpp"
46 #include "memory/iterator.inline.hpp"
47 #include "memory/metadataFactory.hpp"
48 #include "memory/metaspaceClosure.hpp"
49 #include "memory/resourceArea.hpp"
50 #include "memory/universe.hpp"
51 #include "oops/compressedOops.inline.hpp"
52 #include "oops/fieldStreams.inline.hpp"
53 #include "oops/objArrayOop.hpp"
54 #include "oops/oop.inline.hpp"
55 #include "prims/jvmtiExport.hpp"
56 #include "runtime/fieldDescriptor.inline.hpp"
57 #include "runtime/globals_extension.hpp"
58 #include "runtime/init.hpp"
59 #include "runtime/java.hpp"
60 #include "runtime/javaCalls.hpp"
61 #include "runtime/safepoint.hpp"
62 #include "runtime/safepointVerifiers.hpp"
63 #include "utilities/bitMap.inline.hpp"
64 #include "utilities/copy.hpp"
65 #if INCLUDE_G1GC
66 #include "gc/g1/g1CollectedHeap.hpp"
67 #endif
68
69 #if INCLUDE_CDS_JAVA_HEAP
70
71 bool HeapShared::_closed_archive_heap_region_mapped = false;
72 bool HeapShared::_open_archive_heap_region_mapped = false;
73 bool HeapShared::_archive_heap_region_fixed = false;
74 address HeapShared::_narrow_oop_base;
75 int HeapShared::_narrow_oop_shift;
76 DumpedInternedStrings *HeapShared::_dumped_interned_strings = NULL;
77
78 //
79 // If you add new entries to the following tables, you should know what you're doing!
80 //
81
82 // Entry fields for shareable subgraphs archived in the closed archive heap
83 // region. Warning: Objects in the subgraphs should not have reference fields
84 // assigned at runtime.
85 static ArchivableStaticFieldInfo closed_archive_subgraph_entry_fields[] = {
86 {"java/lang/Integer$IntegerCache", "archivedCache"},
87 {"java/lang/Long$LongCache", "archivedCache"},
88 {"java/lang/Byte$ByteCache", "archivedCache"},
89 {"java/lang/Short$ShortCache", "archivedCache"},
90 {"java/lang/Character$CharacterCache", "archivedCache"},
91 {"java/util/jar/Attributes$Name", "KNOWN_NAMES"},
92 {"sun/util/locale/BaseLocale", "constantBaseLocales"},
93 };
94 // Entry fields for subgraphs archived in the open archive heap region.
95 static ArchivableStaticFieldInfo open_archive_subgraph_entry_fields[] = {
96 {"jdk/internal/module/ArchivedModuleGraph", "archivedModuleGraph"},
97 {"java/util/ImmutableCollections", "archivedObjects"},
98 {"java/lang/ModuleLayer", "EMPTY_LAYER"},
99 {"java/lang/module/Configuration", "EMPTY_CONFIGURATION"},
100 {"jdk/internal/math/FDBigInteger", "archivedCaches"},
101 };
102
103 // Entry fields for subgraphs archived in the open archive heap region (full module graph).
104 static ArchivableStaticFieldInfo fmg_open_archive_subgraph_entry_fields[] = {
105 {"jdk/internal/loader/ArchivedClassLoaders", "archivedClassLoaders"},
106 {"jdk/internal/module/ArchivedBootLayer", "archivedBootLayer"},
107 {"java/lang/Module$ArchivedData", "archivedData"},
108 };
109
110 const static int num_closed_archive_subgraph_entry_fields =
111 sizeof(closed_archive_subgraph_entry_fields) / sizeof(ArchivableStaticFieldInfo);
112 const static int num_open_archive_subgraph_entry_fields =
113 sizeof(open_archive_subgraph_entry_fields) / sizeof(ArchivableStaticFieldInfo);
114 const static int num_fmg_open_archive_subgraph_entry_fields =
115 sizeof(fmg_open_archive_subgraph_entry_fields) / sizeof(ArchivableStaticFieldInfo);
116
117 GrowableArrayCHeap<oop, mtClassShared>* HeapShared::_pending_roots = NULL;
118 narrowOop HeapShared::_roots_narrow;
119 OopHandle HeapShared::_roots;
120
121 ////////////////////////////////////////////////////////////////
122 //
123 // Java heap object archiving support
124 //
125 ////////////////////////////////////////////////////////////////
126 void HeapShared::fixup_mapped_heap_regions() {
127 FileMapInfo *mapinfo = FileMapInfo::current_info();
128 mapinfo->fixup_mapped_heap_regions();
129 set_archive_heap_region_fixed();
130 if (is_mapped()) {
131 _roots = OopHandle(Universe::vm_global(), decode_from_archive(_roots_narrow));
132 if (!MetaspaceShared::use_full_module_graph()) {
133 // Need to remove all the archived java.lang.Module objects from HeapShared::roots().
134 ClassLoaderDataShared::clear_archived_oops();
135 }
136 }
137 SystemDictionaryShared::update_archived_mirror_native_pointers();
138 }
139
140 unsigned HeapShared::oop_hash(oop const& p) {
141 assert(!p->mark().has_bias_pattern(),
142 "this object should never have been locked"); // so identity_hash won't safepoin
143 unsigned hash = (unsigned)p->identity_hash();
144 return hash;
145 }
146
147 static void reset_states(oop obj, TRAPS) {
148 Handle h_obj(THREAD, obj);
149 InstanceKlass* klass = InstanceKlass::cast(obj->klass());
150 TempNewSymbol method_name = SymbolTable::new_symbol("resetArchivedStates");
151 Symbol* method_sig = vmSymbols::void_method_signature();
152
153 while (klass != NULL) {
154 Method* method = klass->find_method(method_name, method_sig);
155 if (method != NULL) {
156 assert(method->is_private(), "must be");
157 if (log_is_enabled(Debug, cds)) {
158 ResourceMark rm(THREAD);
159 log_debug(cds)(" calling %s", method->name_and_sig_as_C_string());
160 }
161 JavaValue result(T_VOID);
162 JavaCalls::call_special(&result, h_obj, klass,
163 method_name, method_sig, CHECK);
164 }
165 klass = klass->java_super();
166 }
167 }
168
169 void HeapShared::reset_archived_object_states(TRAPS) {
170 assert(DumpSharedSpaces, "dump-time only");
171 log_debug(cds)("Resetting platform loader");
172 reset_states(SystemDictionary::java_platform_loader(), CHECK);
173 log_debug(cds)("Resetting system loader");
174 reset_states(SystemDictionary::java_system_loader(), CHECK);
175 }
176
177 HeapShared::ArchivedObjectCache* HeapShared::_archived_object_cache = NULL;
178 oop HeapShared::find_archived_heap_object(oop obj) {
179 assert(DumpSharedSpaces, "dump-time only");
180 ArchivedObjectCache* cache = archived_object_cache();
181 oop* p = cache->get(obj);
182 if (p != NULL) {
183 return *p;
184 } else {
185 return NULL;
186 }
187 }
188
189 int HeapShared::append_root(oop obj) {
190 assert(DumpSharedSpaces, "dump-time only");
191
192 // No GC should happen since we aren't scanning _pending_roots.
193 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
194
195 if (_pending_roots == NULL) {
196 _pending_roots = new GrowableArrayCHeap<oop, mtClassShared>(500);
197 }
198
199 return _pending_roots->append(obj);
200 }
201
202 objArrayOop HeapShared::roots() {
203 if (DumpSharedSpaces) {
204 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
205 if (!is_heap_object_archiving_allowed()) {
206 return NULL;
207 }
208 } else {
209 assert(UseSharedSpaces, "must be");
210 }
211
212 objArrayOop roots = (objArrayOop)_roots.resolve();
213 assert(roots != NULL, "should have been initialized");
214 return roots;
215 }
216
217 void HeapShared::set_roots(narrowOop roots) {
218 assert(UseSharedSpaces, "runtime only");
219 assert(open_archive_heap_region_mapped(), "must be");
220 _roots_narrow = roots;
221 }
222
223 // Returns an objArray that contains all the roots of the archived objects
224 oop HeapShared::get_root(int index, bool clear) {
225 assert(index >= 0, "sanity");
226 if (DumpSharedSpaces) {
227 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
228 assert(_pending_roots != NULL, "sanity");
229 return _pending_roots->at(index);
230 } else {
231 assert(UseSharedSpaces, "must be");
232 assert(!_roots.is_empty(), "must have loaded shared heap");
233 oop result = roots()->obj_at(index);
234 if (clear) {
235 clear_root(index);
236 }
237 return result;
238 }
239 }
240
241 void HeapShared::clear_root(int index) {
242 assert(index >= 0, "sanity");
243 assert(UseSharedSpaces, "must be");
244 if (open_archive_heap_region_mapped()) {
245 if (log_is_enabled(Debug, cds, heap)) {
246 oop old = roots()->obj_at(index);
247 log_debug(cds, heap)("Clearing root %d: was " PTR_FORMAT, index, p2i(old));
248 }
249 roots()->obj_at_put(index, NULL);
250 }
251 }
252
253 oop HeapShared::archive_heap_object(oop obj) {
254 assert(DumpSharedSpaces, "dump-time only");
255
256 oop ao = find_archived_heap_object(obj);
257 if (ao != NULL) {
258 // already archived
259 return ao;
260 }
261
262 int len = obj->size();
263 if (G1CollectedHeap::heap()->is_archive_alloc_too_large(len)) {
264 log_debug(cds, heap)("Cannot archive, object (" PTR_FORMAT ") is too large: " SIZE_FORMAT,
265 p2i(obj), (size_t)obj->size());
266 return NULL;
267 }
268
269 oop archived_oop = cast_to_oop(G1CollectedHeap::heap()->archive_mem_allocate(len));
270 if (archived_oop != NULL) {
271 Copy::aligned_disjoint_words(cast_from_oop<HeapWord*>(obj), cast_from_oop<HeapWord*>(archived_oop), len);
272 // Reinitialize markword to remove age/marking/locking/etc.
273 //
274 // We need to retain the identity_hash, because it may have been used by some hashtables
275 // in the shared heap. This also has the side effect of pre-initializing the
276 // identity_hash for all shared objects, so they are less likely to be written
277 // into during run time, increasing the potential of memory sharing.
278 int hash_original = obj->identity_hash();
279 if (UseCompactObjectHeaders) {
280 markWord mark = obj->mark();
281 if (mark.has_displaced_mark_helper()) {
282 mark = mark.displaced_mark_helper();
283 }
284 narrowKlass nklass = mark.narrow_klass();
285 archived_oop->set_mark(markWord::prototype().copy_set_hash(hash_original) LP64_ONLY(.set_narrow_klass(nklass)));
286 } else {
287 archived_oop->set_mark(markWord::prototype().copy_set_hash(hash_original));
288 }
289 assert(archived_oop->mark().is_unlocked(), "sanity");
290
291 DEBUG_ONLY(int hash_archived = archived_oop->identity_hash());
292 assert(hash_original == hash_archived, "Different hash codes: original %x, archived %x", hash_original, hash_archived);
293
294 ArchivedObjectCache* cache = archived_object_cache();
295 cache->put(obj, archived_oop);
296 if (log_is_enabled(Debug, cds, heap)) {
297 ResourceMark rm;
298 log_debug(cds, heap)("Archived heap object " PTR_FORMAT " ==> " PTR_FORMAT " : %s",
299 p2i(obj), p2i(archived_oop), obj->klass()->external_name());
300 }
301 } else {
302 log_error(cds, heap)(
303 "Cannot allocate space for object " PTR_FORMAT " in archived heap region",
304 p2i(obj));
305 vm_direct_exit(-1,
306 err_msg("Out of memory. Please run with a larger Java heap, current MaxHeapSize = "
307 SIZE_FORMAT "M", MaxHeapSize/M));
308 }
309 return archived_oop;
310 }
311
312 void HeapShared::archive_klass_objects() {
313 GrowableArray<Klass*>* klasses = ArchiveBuilder::current()->klasses();
314 assert(klasses != NULL, "sanity");
315 for (int i = 0; i < klasses->length(); i++) {
316 Klass* k = ArchiveBuilder::get_relocated_klass(klasses->at(i));
317
318 // archive mirror object
319 java_lang_Class::archive_mirror(k);
320
321 // archive the resolved_referenes array
322 if (k->is_instance_klass()) {
323 InstanceKlass* ik = InstanceKlass::cast(k);
324 ik->constants()->archive_resolved_references();
325 }
326 }
327 }
328
329 void HeapShared::run_full_gc_in_vm_thread() {
330 if (is_heap_object_archiving_allowed()) {
331 // Avoid fragmentation while archiving heap objects.
332 // We do this inside a safepoint, so that no further allocation can happen after GC
333 // has finished.
334 if (GCLocker::is_active()) {
335 // Just checking for safety ...
336 // This should not happen during -Xshare:dump. If you see this, probably the Java core lib
337 // has been modified such that JNI code is executed in some clean up threads after
338 // we have finished class loading.
339 log_warning(cds)("GC locker is held, unable to start extra compacting GC. This may produce suboptimal results.");
340 } else {
341 log_info(cds)("Run GC ...");
342 Universe::heap()->collect_as_vm_thread(GCCause::_archive_time_gc);
343 log_info(cds)("Run GC done");
344 }
345 }
346 }
347
348 void HeapShared::archive_java_heap_objects(GrowableArray<MemRegion>* closed,
349 GrowableArray<MemRegion>* open) {
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)("Heap range = [" PTR_FORMAT " - " PTR_FORMAT "]",
360 p2i(CompressedOops::begin()), p2i(CompressedOops::end()));
361 log_info(cds)("Dumping objects to closed archive heap region ...");
362 copy_closed_archive_heap_objects(closed);
363
364 log_info(cds)("Dumping objects to open archive heap region ...");
365 copy_open_archive_heap_objects(open);
366
367 destroy_archived_object_cache();
368 }
369
370 G1HeapVerifier::verify_archive_regions();
371 }
372
373 void HeapShared::copy_closed_archive_heap_objects(
374 GrowableArray<MemRegion> * closed_archive) {
375 assert(is_heap_object_archiving_allowed(), "Cannot archive java heap objects");
376
377 G1CollectedHeap::heap()->begin_archive_alloc_range();
378
379 // Archive interned string objects
380 StringTable::write_to_archive(_dumped_interned_strings);
381
382 archive_object_subgraphs(closed_archive_subgraph_entry_fields,
383 num_closed_archive_subgraph_entry_fields,
384 true /* is_closed_archive */,
385 false /* is_full_module_graph */);
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 G1CollectedHeap::heap()->begin_archive_alloc_range(true /* open */);
396
397 java_lang_Class::archive_basic_type_mirrors();
398
399 archive_klass_objects();
400
401 archive_object_subgraphs(open_archive_subgraph_entry_fields,
402 num_open_archive_subgraph_entry_fields,
403 false /* is_closed_archive */,
404 false /* is_full_module_graph */);
405 if (MetaspaceShared::use_full_module_graph()) {
406 archive_object_subgraphs(fmg_open_archive_subgraph_entry_fields,
407 num_fmg_open_archive_subgraph_entry_fields,
408 false /* is_closed_archive */,
409 true /* is_full_module_graph */);
410 ClassLoaderDataShared::init_archived_oops();
411 }
412
413 copy_roots();
414
415 G1CollectedHeap::heap()->end_archive_alloc_range(open_archive,
416 os::vm_allocation_granularity());
417 }
418
419 // Copy _pending_archive_roots into an objArray
420 void HeapShared::copy_roots() {
421 int length = _pending_roots != NULL ? _pending_roots->length() : 0;
422 int size = objArrayOopDesc::object_size(length);
423 Klass* k = Universe::objectArrayKlassObj(); // already relocated to point to archived klass
424 HeapWord* mem = G1CollectedHeap::heap()->archive_mem_allocate(size);
425
426 memset(mem, 0, size * BytesPerWord);
427 {
428 // This is copied from MemAllocator::finish
429 if (UseBiasedLocking) {
430 oopDesc::set_mark(mem, k->prototype_header());
431 } else if (UseCompactObjectHeaders) {
432 oopDesc::release_set_mark(mem, k->prototype_header());
433 } else {
434 oopDesc::set_mark(mem, markWord::prototype());
435 }
436 if (!UseCompactObjectHeaders) {
437 oopDesc::release_set_klass(mem, k);
438 }
439 }
440 {
441 // This is copied from ObjArrayAllocator::initialize
442 arrayOopDesc::set_length(mem, length);
443 }
444
445 _roots = OopHandle(Universe::vm_global(), cast_to_oop(mem));
446 for (int i = 0; i < length; i++) {
447 roots()->obj_at_put(i, _pending_roots->at(i));
448 }
449 log_info(cds)("archived obj roots[%d] = %d words, klass = %p, obj = %p", length, size, k, mem);
450 }
451
452 void HeapShared::init_narrow_oop_decoding(address base, int shift) {
453 _narrow_oop_base = base;
454 _narrow_oop_shift = shift;
455 }
456
457 //
458 // Subgraph archiving support
459 //
460 HeapShared::DumpTimeKlassSubGraphInfoTable* HeapShared::_dump_time_subgraph_info_table = NULL;
461 HeapShared::RunTimeKlassSubGraphInfoTable HeapShared::_run_time_subgraph_info_table;
462
463 // Get the subgraph_info for Klass k. A new subgraph_info is created if
464 // there is no existing one for k. The subgraph_info records the relocated
465 // Klass* of the original k.
466 KlassSubGraphInfo* HeapShared::init_subgraph_info(Klass* k, bool is_full_module_graph) {
467 assert(DumpSharedSpaces, "dump time only");
468 bool created;
469 Klass* relocated_k = ArchiveBuilder::get_relocated_klass(k);
470 KlassSubGraphInfo* info =
471 _dump_time_subgraph_info_table->put_if_absent(relocated_k, KlassSubGraphInfo(relocated_k, is_full_module_graph),
472 &created);
473 assert(created, "must not initialize twice");
474 return info;
475 }
476
477 KlassSubGraphInfo* HeapShared::get_subgraph_info(Klass* k) {
478 assert(DumpSharedSpaces, "dump time only");
479 Klass* relocated_k = ArchiveBuilder::get_relocated_klass(k);
480 KlassSubGraphInfo* info = _dump_time_subgraph_info_table->get(relocated_k);
481 assert(info != NULL, "must have been initialized");
482 return info;
483 }
484
485 // Add an entry field to the current KlassSubGraphInfo.
486 void KlassSubGraphInfo::add_subgraph_entry_field(
487 int static_field_offset, oop v, bool is_closed_archive) {
488 assert(DumpSharedSpaces, "dump time only");
489 if (_subgraph_entry_fields == NULL) {
490 _subgraph_entry_fields =
491 new(ResourceObj::C_HEAP, mtClass) GrowableArray<int>(10, mtClass);
492 }
493 _subgraph_entry_fields->append(static_field_offset);
494 _subgraph_entry_fields->append(HeapShared::append_root(v));
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) {
500 assert(DumpSharedSpaces, "dump time only");
501 Klass* relocated_k = ArchiveBuilder::get_relocated_klass(orig_k);
502
503 if (_subgraph_object_klasses == NULL) {
504 _subgraph_object_klasses =
505 new(ResourceObj::C_HEAP, mtClass) GrowableArray<Klass*>(50, mtClass);
506 }
507
508 assert(ArchiveBuilder::current()->is_in_buffer_space(relocated_k), "must be a shared class");
509
510 if (_k == relocated_k) {
511 // Don't add the Klass containing the sub-graph to it's own klass
512 // initialization list.
513 return;
514 }
515
516 if (relocated_k->is_instance_klass()) {
517 assert(InstanceKlass::cast(relocated_k)->is_shared_boot_class(),
518 "must be boot class");
519 // vmClasses::xxx_klass() are not updated, need to check
520 // the original Klass*
521 if (orig_k == vmClasses::String_klass() ||
522 orig_k == vmClasses::Object_klass()) {
523 // Initialized early during VM initialization. No need to be added
524 // to the sub-graph object class list.
525 return;
526 }
527 } else if (relocated_k->is_objArray_klass()) {
528 Klass* abk = ObjArrayKlass::cast(relocated_k)->bottom_klass();
529 if (abk->is_instance_klass()) {
530 assert(InstanceKlass::cast(abk)->is_shared_boot_class(),
531 "must be boot class");
532 }
533 if (relocated_k == Universe::objectArrayKlassObj()) {
534 // Initialized early during Universe::genesis. No need to be added
535 // to the list.
536 return;
537 }
538 } else {
539 assert(relocated_k->is_typeArray_klass(), "must be");
540 // Primitive type arrays are created early during Universe::genesis.
541 return;
542 }
543
544 if (log_is_enabled(Debug, cds, heap)) {
545 if (!_subgraph_object_klasses->contains(relocated_k)) {
546 ResourceMark rm;
547 log_debug(cds, heap)("Adding klass %s", orig_k->external_name());
548 }
549 }
550
551 _subgraph_object_klasses->append_if_missing(relocated_k);
552 _has_non_early_klasses |= is_non_early_klass(orig_k);
553 }
554
555 bool KlassSubGraphInfo::is_non_early_klass(Klass* k) {
556 if (k->is_objArray_klass()) {
557 k = ObjArrayKlass::cast(k)->bottom_klass();
558 }
559 if (k->is_instance_klass()) {
560 if (!SystemDictionaryShared::is_early_klass(InstanceKlass::cast(k))) {
561 ResourceMark rm;
562 log_info(cds, heap)("non-early: %s", k->external_name());
563 return true;
564 } else {
565 return false;
566 }
567 } else {
568 return false;
569 }
570 }
571
572 // Initialize an archived subgraph_info_record from the given KlassSubGraphInfo.
573 void ArchivedKlassSubGraphInfoRecord::init(KlassSubGraphInfo* info) {
574 _k = info->klass();
575 _entry_field_records = NULL;
576 _subgraph_object_klasses = NULL;
577 _is_full_module_graph = info->is_full_module_graph();
578
579 if (_is_full_module_graph) {
580 // Consider all classes referenced by the full module graph as early -- we will be
581 // allocating objects of these classes during JVMTI early phase, so they cannot
582 // be processed by (non-early) JVMTI ClassFileLoadHook
583 _has_non_early_klasses = false;
584 } else {
585 _has_non_early_klasses = info->has_non_early_klasses();
586 }
587
588 if (_has_non_early_klasses) {
589 ResourceMark rm;
590 log_info(cds, heap)(
591 "Subgraph of klass %s has non-early klasses and cannot be used when JVMTI ClassFileLoadHook is enabled",
592 _k->external_name());
593 }
594
595 // populate the entry fields
596 GrowableArray<int>* entry_fields = info->subgraph_entry_fields();
597 if (entry_fields != NULL) {
598 int num_entry_fields = entry_fields->length();
599 assert(num_entry_fields % 2 == 0, "sanity");
600 _entry_field_records =
601 ArchiveBuilder::new_ro_array<int>(num_entry_fields);
602 for (int i = 0 ; i < num_entry_fields; i++) {
603 _entry_field_records->at_put(i, entry_fields->at(i));
604 }
605 }
606
607 // the Klasses of the objects in the sub-graphs
608 GrowableArray<Klass*>* subgraph_object_klasses = info->subgraph_object_klasses();
609 if (subgraph_object_klasses != NULL) {
610 int num_subgraphs_klasses = subgraph_object_klasses->length();
611 _subgraph_object_klasses =
612 ArchiveBuilder::new_ro_array<Klass*>(num_subgraphs_klasses);
613 for (int i = 0; i < num_subgraphs_klasses; i++) {
614 Klass* subgraph_k = subgraph_object_klasses->at(i);
615 if (log_is_enabled(Info, cds, heap)) {
616 ResourceMark rm;
617 log_info(cds, heap)(
618 "Archived object klass %s (%2d) => %s",
619 _k->external_name(), i, subgraph_k->external_name());
620 }
621 _subgraph_object_klasses->at_put(i, subgraph_k);
622 ArchivePtrMarker::mark_pointer(_subgraph_object_klasses->adr_at(i));
623 }
624 }
625
626 ArchivePtrMarker::mark_pointer(&_k);
627 ArchivePtrMarker::mark_pointer(&_entry_field_records);
628 ArchivePtrMarker::mark_pointer(&_subgraph_object_klasses);
629 }
630
631 struct CopyKlassSubGraphInfoToArchive : StackObj {
632 CompactHashtableWriter* _writer;
633 CopyKlassSubGraphInfoToArchive(CompactHashtableWriter* writer) : _writer(writer) {}
634
635 bool do_entry(Klass* klass, KlassSubGraphInfo& info) {
636 if (info.subgraph_object_klasses() != NULL || info.subgraph_entry_fields() != NULL) {
637 ArchivedKlassSubGraphInfoRecord* record =
638 (ArchivedKlassSubGraphInfoRecord*)ArchiveBuilder::ro_region_alloc(sizeof(ArchivedKlassSubGraphInfoRecord));
639 record->init(&info);
640
641 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary((address)klass);
642 u4 delta = ArchiveBuilder::current()->any_to_offset_u4(record);
643 _writer->add(hash, delta);
644 }
645 return true; // keep on iterating
646 }
647 };
648
649 // Build the records of archived subgraph infos, which include:
650 // - Entry points to all subgraphs from the containing class mirror. The entry
651 // points are static fields in the mirror. For each entry point, the field
652 // offset, value and is_closed_archive flag are recorded in the sub-graph
653 // info. The value is stored back to the corresponding field at runtime.
654 // - A list of klasses that need to be loaded/initialized before archived
655 // java object sub-graph can be accessed at runtime.
656 void HeapShared::write_subgraph_info_table() {
657 // Allocate the contents of the hashtable(s) inside the RO region of the CDS archive.
658 DumpTimeKlassSubGraphInfoTable* d_table = _dump_time_subgraph_info_table;
659 CompactHashtableStats stats;
660
661 _run_time_subgraph_info_table.reset();
662
663 CompactHashtableWriter writer(d_table->_count, &stats);
664 CopyKlassSubGraphInfoToArchive copy(&writer);
665 d_table->iterate(©);
666
667 writer.dump(&_run_time_subgraph_info_table, "subgraphs");
668 }
669
670 void HeapShared::serialize_subgraph_info_table_header(SerializeClosure* soc) {
671 _run_time_subgraph_info_table.serialize_header(soc);
672 }
673
674 static void verify_the_heap(Klass* k, const char* which) {
675 if (VerifyArchivedFields > 0) {
676 ResourceMark rm;
677 log_info(cds, heap)("Verify heap %s initializing static field(s) in %s",
678 which, k->external_name());
679
680 VM_Verify verify_op;
681 VMThread::execute(&verify_op);
682
683 if (VerifyArchivedFields > 1 && is_init_completed()) {
684 // At this time, the oop->klass() of some archived objects in the heap may not
685 // have been loaded into the system dictionary yet. Nevertheless, oop->klass() should
686 // have enough information (object size, oop maps, etc) so that a GC can be safely
687 // performed.
688 //
689 // -XX:VerifyArchivedFields=2 force a GC to happen in such an early stage
690 // to check for GC safety.
691 log_info(cds, heap)("Trigger GC %s initializing static field(s) in %s",
692 which, k->external_name());
693 FlagSetting fs1(VerifyBeforeGC, true);
694 FlagSetting fs2(VerifyDuringGC, true);
695 FlagSetting fs3(VerifyAfterGC, true);
696 Universe::heap()->collect(GCCause::_java_lang_system_gc);
697 }
698 }
699 }
700
701 // Before GC can execute, we must ensure that all oops reachable from HeapShared::roots()
702 // have a valid klass. I.e., oopDesc::klass() must have already been resolved.
703 //
704 // Note: if a ArchivedKlassSubGraphInfoRecord contains non-early classes, and JVMTI
705 // ClassFileLoadHook is enabled, it's possible for this class to be dynamically replaced. In
706 // this case, we will not load the ArchivedKlassSubGraphInfoRecord and will clear its roots.
707 void HeapShared::resolve_classes(JavaThread* THREAD) {
708 if (!is_mapped()) {
709 return; // nothing to do
710 }
711 resolve_classes_for_subgraphs(closed_archive_subgraph_entry_fields,
712 num_closed_archive_subgraph_entry_fields,
713 THREAD);
714 resolve_classes_for_subgraphs(open_archive_subgraph_entry_fields,
715 num_open_archive_subgraph_entry_fields,
716 THREAD);
717 resolve_classes_for_subgraphs(fmg_open_archive_subgraph_entry_fields,
718 num_fmg_open_archive_subgraph_entry_fields,
719 THREAD);
720 }
721
722 void HeapShared::resolve_classes_for_subgraphs(ArchivableStaticFieldInfo fields[],
723 int num, JavaThread* THREAD) {
724 for (int i = 0; i < num; i++) {
725 ArchivableStaticFieldInfo* info = &fields[i];
726 TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name);
727 InstanceKlass* k = SystemDictionaryShared::find_builtin_class(klass_name);
728 assert(k != NULL && k->is_shared_boot_class(), "sanity");
729 resolve_classes_for_subgraph_of(k, THREAD);
730 }
731 }
732
733 void HeapShared::resolve_classes_for_subgraph_of(Klass* k, JavaThread* THREAD) {
734 ExceptionMark em(THREAD);
735 const ArchivedKlassSubGraphInfoRecord* record =
736 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/false, THREAD);
737 if (HAS_PENDING_EXCEPTION) {
738 CLEAR_PENDING_EXCEPTION;
739 }
740 if (record == NULL) {
741 clear_archived_roots_of(k);
742 }
743 }
744
745 void HeapShared::initialize_from_archived_subgraph(Klass* k, JavaThread* THREAD) {
746 if (!is_mapped()) {
747 return; // nothing to do
748 }
749
750 ExceptionMark em(THREAD);
751 const ArchivedKlassSubGraphInfoRecord* record =
752 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/true, THREAD);
753
754 if (HAS_PENDING_EXCEPTION) {
755 CLEAR_PENDING_EXCEPTION;
756 // None of the field value will be set if there was an exception when initializing the classes.
757 // The java code will not see any of the archived objects in the
758 // subgraphs referenced from k in this case.
759 return;
760 }
761
762 if (record != NULL) {
763 init_archived_fields_for(k, record);
764 }
765 }
766
767 const ArchivedKlassSubGraphInfoRecord*
768 HeapShared::resolve_or_init_classes_for_subgraph_of(Klass* k, bool do_init, TRAPS) {
769 assert(!DumpSharedSpaces, "Should not be called with DumpSharedSpaces");
770
771 if (!k->is_shared()) {
772 return NULL;
773 }
774 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary_quick(k);
775 const ArchivedKlassSubGraphInfoRecord* record = _run_time_subgraph_info_table.lookup(k, hash, 0);
776
777 // Initialize from archived data. Currently this is done only
778 // during VM initialization time. No lock is needed.
779 if (record != NULL) {
780 if (record->is_full_module_graph() && !MetaspaceShared::use_full_module_graph()) {
781 if (log_is_enabled(Info, cds, heap)) {
782 ResourceMark rm(THREAD);
783 log_info(cds, heap)("subgraph %s cannot be used because full module graph is disabled",
784 k->external_name());
785 }
786 return NULL;
787 }
788
789 if (record->has_non_early_klasses() && JvmtiExport::should_post_class_file_load_hook()) {
790 if (log_is_enabled(Info, cds, heap)) {
791 ResourceMark rm(THREAD);
792 log_info(cds, heap)("subgraph %s cannot be used because JVMTI ClassFileLoadHook is enabled",
793 k->external_name());
794 }
795 return NULL;
796 }
797
798 resolve_or_init(k, do_init, CHECK_NULL);
799
800 // Load/link/initialize the klasses of the objects in the subgraph.
801 // NULL class loader is used.
802 Array<Klass*>* klasses = record->subgraph_object_klasses();
803 if (klasses != NULL) {
804 for (int i = 0; i < klasses->length(); i++) {
805 Klass* klass = klasses->at(i);
806 if (!klass->is_shared()) {
807 return NULL;
808 }
809 resolve_or_init(klass, do_init, CHECK_NULL);
810 }
811 }
812 }
813
814 return record;
815 }
816
817 void HeapShared::resolve_or_init(Klass* k, bool do_init, TRAPS) {
818 if (!do_init) {
819 if (k->class_loader_data() == NULL) {
820 Klass* resolved_k = SystemDictionary::resolve_or_null(k->name(), CHECK);
821 assert(resolved_k == k, "classes used by archived heap must not be replaced by JVMTI ClassFileLoadHook");
822 }
823 } else {
824 assert(k->class_loader_data() != NULL, "must have been resolved by HeapShared::resolve_classes");
825 if (k->is_instance_klass()) {
826 InstanceKlass* ik = InstanceKlass::cast(k);
827 ik->initialize(CHECK);
828 } else if (k->is_objArray_klass()) {
829 ObjArrayKlass* oak = ObjArrayKlass::cast(k);
830 oak->initialize(CHECK);
831 }
832 }
833 }
834
835 void HeapShared::init_archived_fields_for(Klass* k, const ArchivedKlassSubGraphInfoRecord* record) {
836 verify_the_heap(k, "before");
837
838 // Load the subgraph entry fields from the record and store them back to
839 // the corresponding fields within the mirror.
840 oop m = k->java_mirror();
841 Array<int>* entry_field_records = record->entry_field_records();
842 if (entry_field_records != NULL) {
843 int efr_len = entry_field_records->length();
844 assert(efr_len % 2 == 0, "sanity");
845 for (int i = 0; i < efr_len; i += 2) {
846 int field_offset = entry_field_records->at(i);
847 int root_index = entry_field_records->at(i+1);
848 oop v = get_root(root_index, /*clear=*/true);
849 m->obj_field_put(field_offset, v);
850 log_debug(cds, heap)(" " PTR_FORMAT " init field @ %2d = " PTR_FORMAT, p2i(k), field_offset, p2i(v));
851 }
852
853 // Done. Java code can see the archived sub-graphs referenced from k's
854 // mirror after this point.
855 if (log_is_enabled(Info, cds, heap)) {
856 ResourceMark rm;
857 log_info(cds, heap)("initialize_from_archived_subgraph %s " PTR_FORMAT "%s",
858 k->external_name(), p2i(k), JvmtiExport::is_early_phase() ? " (early)" : "");
859 }
860 }
861
862 verify_the_heap(k, "after ");
863 }
864
865 void HeapShared::clear_archived_roots_of(Klass* k) {
866 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary_quick(k);
867 const ArchivedKlassSubGraphInfoRecord* record = _run_time_subgraph_info_table.lookup(k, hash, 0);
868 if (record != NULL) {
869 Array<int>* entry_field_records = record->entry_field_records();
870 if (entry_field_records != NULL) {
871 int efr_len = entry_field_records->length();
872 assert(efr_len % 2 == 0, "sanity");
873 for (int i = 0; i < efr_len; i += 2) {
874 int root_index = entry_field_records->at(i+1);
875 clear_root(root_index);
876 }
877 }
878 }
879 }
880
881 class WalkOopAndArchiveClosure: public BasicOopIterateClosure {
882 int _level;
883 bool _is_closed_archive;
884 bool _record_klasses_only;
885 KlassSubGraphInfo* _subgraph_info;
886 oop _orig_referencing_obj;
887 oop _archived_referencing_obj;
888 public:
889 WalkOopAndArchiveClosure(int level,
890 bool is_closed_archive,
891 bool record_klasses_only,
892 KlassSubGraphInfo* subgraph_info,
893 oop orig, oop archived) :
894 _level(level), _is_closed_archive(is_closed_archive),
895 _record_klasses_only(record_klasses_only),
896 _subgraph_info(subgraph_info),
897 _orig_referencing_obj(orig), _archived_referencing_obj(archived) {}
898 void do_oop(narrowOop *p) { WalkOopAndArchiveClosure::do_oop_work(p); }
899 void do_oop( oop *p) { WalkOopAndArchiveClosure::do_oop_work(p); }
900
901 protected:
902 template <class T> void do_oop_work(T *p) {
903 oop obj = RawAccess<>::oop_load(p);
904 if (!CompressedOops::is_null(obj)) {
905 assert(!HeapShared::is_archived_object(obj),
906 "original objects must not point to archived objects");
907
908 size_t field_delta = pointer_delta(p, _orig_referencing_obj, sizeof(char));
909 T* new_p = (T*)(cast_from_oop<address>(_archived_referencing_obj) + field_delta);
910
911 if (!_record_klasses_only && log_is_enabled(Debug, cds, heap)) {
912 ResourceMark rm;
913 log_debug(cds, heap)("(%d) %s[" SIZE_FORMAT "] ==> " PTR_FORMAT " size %d %s", _level,
914 _orig_referencing_obj->klass()->external_name(), field_delta,
915 p2i(obj), obj->size() * HeapWordSize, obj->klass()->external_name());
916 LogTarget(Trace, cds, heap) log;
917 LogStream out(log);
918 obj->print_on(&out);
919 }
920
921 oop archived = HeapShared::archive_reachable_objects_from(
922 _level + 1, _subgraph_info, obj, _is_closed_archive);
923 assert(archived != NULL, "VM should have exited with unarchivable objects for _level > 1");
924 assert(HeapShared::is_archived_object(archived), "must be");
925
926 if (!_record_klasses_only) {
927 // Update the reference in the archived copy of the referencing object.
928 log_debug(cds, heap)("(%d) updating oop @[" PTR_FORMAT "] " PTR_FORMAT " ==> " PTR_FORMAT,
929 _level, p2i(new_p), p2i(obj), p2i(archived));
930 RawAccess<IS_NOT_NULL>::oop_store(new_p, archived);
931 }
932 }
933 }
934 };
935
936 void HeapShared::check_closed_archive_heap_region_object(InstanceKlass* k) {
937 // Check fields in the object
938 for (JavaFieldStream fs(k); !fs.done(); fs.next()) {
939 if (!fs.access_flags().is_static()) {
940 BasicType ft = fs.field_descriptor().field_type();
941 if (!fs.access_flags().is_final() && is_reference_type(ft)) {
942 ResourceMark rm;
943 log_warning(cds, heap)(
944 "Please check reference field in %s instance in closed archive heap region: %s %s",
945 k->external_name(), (fs.name())->as_C_string(),
946 (fs.signature())->as_C_string());
947 }
948 }
949 }
950 }
951
952 void HeapShared::check_module_oop(oop orig_module_obj) {
953 assert(DumpSharedSpaces, "must be");
954 assert(java_lang_Module::is_instance(orig_module_obj), "must be");
955 ModuleEntry* orig_module_ent = java_lang_Module::module_entry_raw(orig_module_obj);
956 if (orig_module_ent == NULL) {
957 // These special Module objects are created in Java code. They are not
958 // defined via Modules::define_module(), so they don't have a ModuleEntry:
959 // java.lang.Module::ALL_UNNAMED_MODULE
960 // java.lang.Module::EVERYONE_MODULE
961 // jdk.internal.loader.ClassLoaders$BootClassLoader::unnamedModule
962 assert(java_lang_Module::name(orig_module_obj) == NULL, "must be unnamed");
963 log_info(cds, heap)("Module oop with No ModuleEntry* @[" PTR_FORMAT "]", p2i(orig_module_obj));
964 } else {
965 ClassLoaderData* loader_data = orig_module_ent->loader_data();
966 assert(loader_data->is_builtin_class_loader_data(), "must be");
967 }
968 }
969
970
971 // (1) If orig_obj has not been archived yet, archive it.
972 // (2) If orig_obj has not been seen yet (since start_recording_subgraph() was called),
973 // trace all objects that are reachable from it, and make sure these objects are archived.
974 // (3) Record the klasses of all orig_obj and all reachable objects.
975 oop HeapShared::archive_reachable_objects_from(int level,
976 KlassSubGraphInfo* subgraph_info,
977 oop orig_obj,
978 bool is_closed_archive) {
979 assert(orig_obj != NULL, "must be");
980 assert(!is_archived_object(orig_obj), "sanity");
981
982 if (!JavaClasses::is_supported_for_archiving(orig_obj)) {
983 // This object has injected fields that cannot be supported easily, so we disallow them for now.
984 // If you get an error here, you probably made a change in the JDK library that has added
985 // these objects that are referenced (directly or indirectly) by static fields.
986 ResourceMark rm;
987 log_error(cds, heap)("Cannot archive object of class %s", orig_obj->klass()->external_name());
988 vm_direct_exit(1);
989 }
990
991 // java.lang.Class instances cannot be included in an archived object sub-graph. We only support
992 // them as Klass::_archived_mirror because they need to be specially restored at run time.
993 //
994 // If you get an error here, you probably made a change in the JDK library that has added a Class
995 // object that is referenced (directly or indirectly) by static fields.
996 if (java_lang_Class::is_instance(orig_obj)) {
997 log_error(cds, heap)("(%d) Unknown java.lang.Class object is in the archived sub-graph", level);
998 vm_direct_exit(1);
999 }
1000
1001 oop archived_obj = find_archived_heap_object(orig_obj);
1002 if (java_lang_String::is_instance(orig_obj) && archived_obj != NULL) {
1003 // To save time, don't walk strings that are already archived. They just contain
1004 // pointers to a type array, whose klass doesn't need to be recorded.
1005 return archived_obj;
1006 }
1007
1008 if (has_been_seen_during_subgraph_recording(orig_obj)) {
1009 // orig_obj has already been archived and traced. Nothing more to do.
1010 return archived_obj;
1011 } else {
1012 set_has_been_seen_during_subgraph_recording(orig_obj);
1013 }
1014
1015 bool record_klasses_only = (archived_obj != NULL);
1016 if (archived_obj == NULL) {
1017 ++_num_new_archived_objs;
1018 archived_obj = archive_heap_object(orig_obj);
1019 if (archived_obj == NULL) {
1020 // Skip archiving the sub-graph referenced from the current entry field.
1021 ResourceMark rm;
1022 log_error(cds, heap)(
1023 "Cannot archive the sub-graph referenced from %s object ("
1024 PTR_FORMAT ") size %d, skipped.",
1025 orig_obj->klass()->external_name(), p2i(orig_obj), orig_obj->size() * HeapWordSize);
1026 if (level == 1) {
1027 // Don't archive a subgraph root that's too big. For archives static fields, that's OK
1028 // as the Java code will take care of initializing this field dynamically.
1029 return NULL;
1030 } else {
1031 // We don't know how to handle an object that has been archived, but some of its reachable
1032 // objects cannot be archived. Bail out for now. We might need to fix this in the future if
1033 // we have a real use case.
1034 vm_direct_exit(1);
1035 }
1036 }
1037
1038 if (java_lang_Module::is_instance(orig_obj)) {
1039 check_module_oop(orig_obj);
1040 java_lang_Module::set_module_entry(archived_obj, NULL);
1041 java_lang_Module::set_loader(archived_obj, NULL);
1042 } else if (java_lang_ClassLoader::is_instance(orig_obj)) {
1043 // class_data will be restored explicitly at run time.
1044 guarantee(orig_obj == SystemDictionary::java_platform_loader() ||
1045 orig_obj == SystemDictionary::java_system_loader() ||
1046 java_lang_ClassLoader::loader_data_raw(orig_obj) == NULL, "must be");
1047 java_lang_ClassLoader::release_set_loader_data(archived_obj, NULL);
1048 }
1049 }
1050
1051 assert(archived_obj != NULL, "must be");
1052 Klass *orig_k = orig_obj->klass();
1053 subgraph_info->add_subgraph_object_klass(orig_k);
1054
1055 WalkOopAndArchiveClosure walker(level, is_closed_archive, record_klasses_only,
1056 subgraph_info, orig_obj, archived_obj);
1057 orig_obj->oop_iterate(&walker);
1058 if (is_closed_archive && orig_k->is_instance_klass()) {
1059 check_closed_archive_heap_region_object(InstanceKlass::cast(orig_k));
1060 }
1061 return archived_obj;
1062 }
1063
1064 //
1065 // Start from the given static field in a java mirror and archive the
1066 // complete sub-graph of java heap objects that are reached directly
1067 // or indirectly from the starting object by following references.
1068 // Sub-graph archiving restrictions (current):
1069 //
1070 // - All classes of objects in the archived sub-graph (including the
1071 // entry class) must be boot class only.
1072 // - No java.lang.Class instance (java mirror) can be included inside
1073 // an archived sub-graph. Mirror can only be the sub-graph entry object.
1074 //
1075 // The Java heap object sub-graph archiving process (see
1076 // WalkOopAndArchiveClosure):
1077 //
1078 // 1) Java object sub-graph archiving starts from a given static field
1079 // within a Class instance (java mirror). If the static field is a
1080 // refererence field and points to a non-null java object, proceed to
1081 // the next step.
1082 //
1083 // 2) Archives the referenced java object. If an archived copy of the
1084 // current object already exists, updates the pointer in the archived
1085 // copy of the referencing object to point to the current archived object.
1086 // Otherwise, proceed to the next step.
1087 //
1088 // 3) Follows all references within the current java object and recursively
1089 // archive the sub-graph of objects starting from each reference.
1090 //
1091 // 4) Updates the pointer in the archived copy of referencing object to
1092 // point to the current archived object.
1093 //
1094 // 5) The Klass of the current java object is added to the list of Klasses
1095 // for loading and initialzing before any object in the archived graph can
1096 // be accessed at runtime.
1097 //
1098 void HeapShared::archive_reachable_objects_from_static_field(InstanceKlass *k,
1099 const char* klass_name,
1100 int field_offset,
1101 const char* field_name,
1102 bool is_closed_archive) {
1103 assert(DumpSharedSpaces, "dump time only");
1104 assert(k->is_shared_boot_class(), "must be boot class");
1105
1106 oop m = k->java_mirror();
1107
1108 KlassSubGraphInfo* subgraph_info = get_subgraph_info(k);
1109 oop f = m->obj_field(field_offset);
1110
1111 log_debug(cds, heap)("Start archiving from: %s::%s (" PTR_FORMAT ")", klass_name, field_name, p2i(f));
1112
1113 if (!CompressedOops::is_null(f)) {
1114 if (log_is_enabled(Trace, cds, heap)) {
1115 LogTarget(Trace, cds, heap) log;
1116 LogStream out(log);
1117 f->print_on(&out);
1118 }
1119
1120 oop af = archive_reachable_objects_from(1, subgraph_info, f, is_closed_archive);
1121
1122 if (af == NULL) {
1123 log_error(cds, heap)("Archiving failed %s::%s (some reachable objects cannot be archived)",
1124 klass_name, field_name);
1125 } else {
1126 // Note: the field value is not preserved in the archived mirror.
1127 // Record the field as a new subGraph entry point. The recorded
1128 // information is restored from the archive at runtime.
1129 subgraph_info->add_subgraph_entry_field(field_offset, af, is_closed_archive);
1130 log_info(cds, heap)("Archived field %s::%s => " PTR_FORMAT, klass_name, field_name, p2i(af));
1131 }
1132 } else {
1133 // The field contains null, we still need to record the entry point,
1134 // so it can be restored at runtime.
1135 subgraph_info->add_subgraph_entry_field(field_offset, NULL, false);
1136 }
1137 }
1138
1139 #ifndef PRODUCT
1140 class VerifySharedOopClosure: public BasicOopIterateClosure {
1141 private:
1142 bool _is_archived;
1143
1144 public:
1145 VerifySharedOopClosure(bool is_archived) : _is_archived(is_archived) {}
1146
1147 void do_oop(narrowOop *p) { VerifySharedOopClosure::do_oop_work(p); }
1148 void do_oop( oop *p) { VerifySharedOopClosure::do_oop_work(p); }
1149
1150 protected:
1151 template <class T> void do_oop_work(T *p) {
1152 oop obj = RawAccess<>::oop_load(p);
1153 if (!CompressedOops::is_null(obj)) {
1154 HeapShared::verify_reachable_objects_from(obj, _is_archived);
1155 }
1156 }
1157 };
1158
1159 void HeapShared::verify_subgraph_from_static_field(InstanceKlass* k, int field_offset) {
1160 assert(DumpSharedSpaces, "dump time only");
1161 assert(k->is_shared_boot_class(), "must be boot class");
1162
1163 oop m = k->java_mirror();
1164 oop f = m->obj_field(field_offset);
1165 if (!CompressedOops::is_null(f)) {
1166 verify_subgraph_from(f);
1167 }
1168 }
1169
1170 void HeapShared::verify_subgraph_from(oop orig_obj) {
1171 oop archived_obj = find_archived_heap_object(orig_obj);
1172 if (archived_obj == NULL) {
1173 // It's OK for the root of a subgraph to be not archived. See comments in
1174 // archive_reachable_objects_from().
1175 return;
1176 }
1177
1178 // Verify that all objects reachable from orig_obj are archived.
1179 init_seen_objects_table();
1180 verify_reachable_objects_from(orig_obj, false);
1181 delete_seen_objects_table();
1182
1183 // Note: we could also verify that all objects reachable from the archived
1184 // copy of orig_obj can only point to archived objects, with:
1185 // init_seen_objects_table();
1186 // verify_reachable_objects_from(archived_obj, true);
1187 // init_seen_objects_table();
1188 // but that's already done in G1HeapVerifier::verify_archive_regions so we
1189 // won't do it here.
1190 }
1191
1192 void HeapShared::verify_reachable_objects_from(oop obj, bool is_archived) {
1193 _num_total_verifications ++;
1194 if (!has_been_seen_during_subgraph_recording(obj)) {
1195 set_has_been_seen_during_subgraph_recording(obj);
1196
1197 if (is_archived) {
1198 assert(is_archived_object(obj), "must be");
1199 assert(find_archived_heap_object(obj) == NULL, "must be");
1200 } else {
1201 assert(!is_archived_object(obj), "must be");
1202 assert(find_archived_heap_object(obj) != NULL, "must be");
1203 }
1204
1205 VerifySharedOopClosure walker(is_archived);
1206 obj->oop_iterate(&walker);
1207 }
1208 }
1209 #endif
1210
1211 HeapShared::SeenObjectsTable* HeapShared::_seen_objects_table = NULL;
1212 int HeapShared::_num_new_walked_objs;
1213 int HeapShared::_num_new_archived_objs;
1214 int HeapShared::_num_old_recorded_klasses;
1215
1216 int HeapShared::_num_total_subgraph_recordings = 0;
1217 int HeapShared::_num_total_walked_objs = 0;
1218 int HeapShared::_num_total_archived_objs = 0;
1219 int HeapShared::_num_total_recorded_klasses = 0;
1220 int HeapShared::_num_total_verifications = 0;
1221
1222 bool HeapShared::has_been_seen_during_subgraph_recording(oop obj) {
1223 return _seen_objects_table->get(obj) != NULL;
1224 }
1225
1226 void HeapShared::set_has_been_seen_during_subgraph_recording(oop obj) {
1227 assert(!has_been_seen_during_subgraph_recording(obj), "sanity");
1228 _seen_objects_table->put(obj, true);
1229 ++ _num_new_walked_objs;
1230 }
1231
1232 void HeapShared::start_recording_subgraph(InstanceKlass *k, const char* class_name, bool is_full_module_graph) {
1233 log_info(cds, heap)("Start recording subgraph(s) for archived fields in %s", class_name);
1234 init_subgraph_info(k, is_full_module_graph);
1235 init_seen_objects_table();
1236 _num_new_walked_objs = 0;
1237 _num_new_archived_objs = 0;
1238 _num_old_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses();
1239 }
1240
1241 void HeapShared::done_recording_subgraph(InstanceKlass *k, const char* class_name) {
1242 int num_new_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses() -
1243 _num_old_recorded_klasses;
1244 log_info(cds, heap)("Done recording subgraph(s) for archived fields in %s: "
1245 "walked %d objs, archived %d new objs, recorded %d classes",
1246 class_name, _num_new_walked_objs, _num_new_archived_objs,
1247 num_new_recorded_klasses);
1248
1249 delete_seen_objects_table();
1250
1251 _num_total_subgraph_recordings ++;
1252 _num_total_walked_objs += _num_new_walked_objs;
1253 _num_total_archived_objs += _num_new_archived_objs;
1254 _num_total_recorded_klasses += num_new_recorded_klasses;
1255 }
1256
1257 class ArchivableStaticFieldFinder: public FieldClosure {
1258 InstanceKlass* _ik;
1259 Symbol* _field_name;
1260 bool _found;
1261 int _offset;
1262 public:
1263 ArchivableStaticFieldFinder(InstanceKlass* ik, Symbol* field_name) :
1264 _ik(ik), _field_name(field_name), _found(false), _offset(-1) {}
1265
1266 virtual void do_field(fieldDescriptor* fd) {
1267 if (fd->name() == _field_name) {
1268 assert(!_found, "fields cannot be overloaded");
1269 assert(is_reference_type(fd->field_type()), "can archive only fields that are references");
1270 _found = true;
1271 _offset = fd->offset();
1272 }
1273 }
1274 bool found() { return _found; }
1275 int offset() { return _offset; }
1276 };
1277
1278 void HeapShared::init_subgraph_entry_fields(ArchivableStaticFieldInfo fields[],
1279 int num, TRAPS) {
1280 for (int i = 0; i < num; i++) {
1281 ArchivableStaticFieldInfo* info = &fields[i];
1282 TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name);
1283 TempNewSymbol field_name = SymbolTable::new_symbol(info->field_name);
1284
1285 Klass* k = SystemDictionary::resolve_or_fail(klass_name, true, CHECK);
1286 InstanceKlass* ik = InstanceKlass::cast(k);
1287 assert(InstanceKlass::cast(ik)->is_shared_boot_class(),
1288 "Only support boot classes");
1289 ik->initialize(CHECK);
1290
1291 ArchivableStaticFieldFinder finder(ik, field_name);
1292 ik->do_local_static_fields(&finder);
1293 assert(finder.found(), "field must exist");
1294
1295 info->klass = ik;
1296 info->offset = finder.offset();
1297 }
1298 }
1299
1300 void HeapShared::init_subgraph_entry_fields(TRAPS) {
1301 assert(is_heap_object_archiving_allowed(), "Sanity check");
1302 _dump_time_subgraph_info_table = new (ResourceObj::C_HEAP, mtClass)DumpTimeKlassSubGraphInfoTable();
1303 init_subgraph_entry_fields(closed_archive_subgraph_entry_fields,
1304 num_closed_archive_subgraph_entry_fields,
1305 CHECK);
1306 init_subgraph_entry_fields(open_archive_subgraph_entry_fields,
1307 num_open_archive_subgraph_entry_fields,
1308 CHECK);
1309 if (MetaspaceShared::use_full_module_graph()) {
1310 init_subgraph_entry_fields(fmg_open_archive_subgraph_entry_fields,
1311 num_fmg_open_archive_subgraph_entry_fields,
1312 CHECK);
1313 }
1314 }
1315
1316 void HeapShared::init_for_dumping(TRAPS) {
1317 if (is_heap_object_archiving_allowed()) {
1318 _dumped_interned_strings = new (ResourceObj::C_HEAP, mtClass)DumpedInternedStrings();
1319 init_subgraph_entry_fields(CHECK);
1320 }
1321 }
1322
1323 void HeapShared::archive_object_subgraphs(ArchivableStaticFieldInfo fields[],
1324 int num, bool is_closed_archive,
1325 bool is_full_module_graph) {
1326 _num_total_subgraph_recordings = 0;
1327 _num_total_walked_objs = 0;
1328 _num_total_archived_objs = 0;
1329 _num_total_recorded_klasses = 0;
1330 _num_total_verifications = 0;
1331
1332 // For each class X that has one or more archived fields:
1333 // [1] Dump the subgraph of each archived field
1334 // [2] Create a list of all the class of the objects that can be reached
1335 // by any of these static fields.
1336 // At runtime, these classes are initialized before X's archived fields
1337 // are restored by HeapShared::initialize_from_archived_subgraph().
1338 int i;
1339 for (i = 0; i < num; ) {
1340 ArchivableStaticFieldInfo* info = &fields[i];
1341 const char* klass_name = info->klass_name;
1342 start_recording_subgraph(info->klass, klass_name, is_full_module_graph);
1343
1344 // If you have specified consecutive fields of the same klass in
1345 // fields[], these will be archived in the same
1346 // {start_recording_subgraph ... done_recording_subgraph} pass to
1347 // save time.
1348 for (; i < num; i++) {
1349 ArchivableStaticFieldInfo* f = &fields[i];
1350 if (f->klass_name != klass_name) {
1351 break;
1352 }
1353
1354 archive_reachable_objects_from_static_field(f->klass, f->klass_name,
1355 f->offset, f->field_name,
1356 is_closed_archive);
1357 }
1358 done_recording_subgraph(info->klass, klass_name);
1359 }
1360
1361 log_info(cds, heap)("Archived subgraph records in %s archive heap region = %d",
1362 is_closed_archive ? "closed" : "open",
1363 _num_total_subgraph_recordings);
1364 log_info(cds, heap)(" Walked %d objects", _num_total_walked_objs);
1365 log_info(cds, heap)(" Archived %d objects", _num_total_archived_objs);
1366 log_info(cds, heap)(" Recorded %d klasses", _num_total_recorded_klasses);
1367
1368 #ifndef PRODUCT
1369 for (int i = 0; i < num; i++) {
1370 ArchivableStaticFieldInfo* f = &fields[i];
1371 verify_subgraph_from_static_field(f->klass, f->offset);
1372 }
1373 log_info(cds, heap)(" Verified %d references", _num_total_verifications);
1374 #endif
1375 }
1376
1377 // Not all the strings in the global StringTable are dumped into the archive, because
1378 // some of those strings may be only referenced by classes that are excluded from
1379 // the archive. We need to explicitly mark the strings that are:
1380 // [1] used by classes that WILL be archived;
1381 // [2] included in the SharedArchiveConfigFile.
1382 void HeapShared::add_to_dumped_interned_strings(oop string) {
1383 assert_at_safepoint(); // DumpedInternedStrings uses raw oops
1384 bool created;
1385 _dumped_interned_strings->put_if_absent(string, true, &created);
1386 }
1387
1388 // At dump-time, find the location of all the non-null oop pointers in an archived heap
1389 // region. This way we can quickly relocate all the pointers without using
1390 // BasicOopIterateClosure at runtime.
1391 class FindEmbeddedNonNullPointers: public BasicOopIterateClosure {
1392 narrowOop* _start;
1393 BitMap *_oopmap;
1394 int _num_total_oops;
1395 int _num_null_oops;
1396 public:
1397 FindEmbeddedNonNullPointers(narrowOop* start, BitMap* oopmap)
1398 : _start(start), _oopmap(oopmap), _num_total_oops(0), _num_null_oops(0) {}
1399
1400 virtual void do_oop(narrowOop* p) {
1401 _num_total_oops ++;
1402 narrowOop v = *p;
1403 if (!CompressedOops::is_null(v)) {
1404 size_t idx = p - _start;
1405 _oopmap->set_bit(idx);
1406 } else {
1407 _num_null_oops ++;
1408 }
1409 }
1410 virtual void do_oop(oop *p) {
1411 ShouldNotReachHere();
1412 }
1413 int num_total_oops() const { return _num_total_oops; }
1414 int num_null_oops() const { return _num_null_oops; }
1415 };
1416
1417 ResourceBitMap HeapShared::calculate_oopmap(MemRegion region) {
1418 assert(UseCompressedOops, "must be");
1419 size_t num_bits = region.byte_size() / sizeof(narrowOop);
1420 ResourceBitMap oopmap(num_bits);
1421
1422 HeapWord* p = region.start();
1423 HeapWord* end = region.end();
1424 FindEmbeddedNonNullPointers finder((narrowOop*)p, &oopmap);
1425 ArchiveBuilder* builder = DumpSharedSpaces ? ArchiveBuilder::current() : NULL;
1426
1427 int num_objs = 0;
1428 while (p < end) {
1429 oop o = cast_to_oop(p);
1430 o->oop_iterate(&finder);
1431 p += o->size();
1432 if (DumpSharedSpaces) {
1433 builder->relocate_klass_ptr(o);
1434 }
1435 ++ num_objs;
1436 }
1437
1438 log_info(cds, heap)("calculate_oopmap: objects = %6d, embedded oops = %7d, nulls = %7d",
1439 num_objs, finder.num_total_oops(), finder.num_null_oops());
1440 return oopmap;
1441 }
1442
1443 // Patch all the embedded oop pointers inside an archived heap region,
1444 // to be consistent with the runtime oop encoding.
1445 class PatchEmbeddedPointers: public BitMapClosure {
1446 narrowOop* _start;
1447
1448 public:
1449 PatchEmbeddedPointers(narrowOop* start) : _start(start) {}
1450
1451 bool do_bit(size_t offset) {
1452 narrowOop* p = _start + offset;
1453 narrowOop v = *p;
1454 assert(!CompressedOops::is_null(v), "null oops should have been filtered out at dump time");
1455 oop o = HeapShared::decode_from_archive(v);
1456 RawAccess<IS_NOT_NULL>::oop_store(p, o);
1457 return true;
1458 }
1459 };
1460
1461 void HeapShared::patch_archived_heap_embedded_pointers(MemRegion region, address oopmap,
1462 size_t oopmap_size_in_bits) {
1463 BitMapView bm((BitMap::bm_word_t*)oopmap, oopmap_size_in_bits);
1464
1465 #ifndef PRODUCT
1466 ResourceMark rm;
1467 ResourceBitMap checkBm = calculate_oopmap(region);
1468 assert(bm.is_same(checkBm), "sanity");
1469 #endif
1470
1471 PatchEmbeddedPointers patcher((narrowOop*)region.start());
1472 bm.iterate(&patcher);
1473 }
1474
1475 #endif // INCLUDE_CDS_JAVA_HEAP