1 /*
2 * Copyright (c) 2018, 2022, 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/archiveHeapLoader.hpp"
28 #include "cds/archiveUtils.hpp"
29 #include "cds/cdsHeapVerifier.hpp"
30 #include "cds/heapShared.hpp"
31 #include "cds/metaspaceShared.hpp"
32 #include "classfile/classLoaderData.hpp"
33 #include "classfile/classLoaderDataShared.hpp"
34 #include "classfile/javaClasses.inline.hpp"
35 #include "classfile/moduleEntry.hpp"
36 #include "classfile/stringTable.hpp"
37 #include "classfile/symbolTable.hpp"
38 #include "classfile/systemDictionary.hpp"
39 #include "classfile/systemDictionaryShared.hpp"
40 #include "classfile/vmClasses.hpp"
41 #include "classfile/vmSymbols.hpp"
42 #include "gc/shared/collectedHeap.hpp"
43 #include "gc/shared/gcLocker.hpp"
44 #include "gc/shared/gcVMOperations.hpp"
45 #include "logging/log.hpp"
46 #include "logging/logStream.hpp"
47 #include "memory/iterator.inline.hpp"
48 #include "memory/resourceArea.hpp"
49 #include "memory/universe.hpp"
50 #include "oops/compressedOops.inline.hpp"
51 #include "oops/fieldStreams.inline.hpp"
52 #include "oops/objArrayOop.inline.hpp"
53 #include "oops/oop.inline.hpp"
54 #include "oops/typeArrayOop.inline.hpp"
55 #include "prims/jvmtiExport.hpp"
56 #include "runtime/fieldDescriptor.inline.hpp"
57 #include "runtime/init.hpp"
58 #include "runtime/javaCalls.hpp"
59 #include "runtime/safepointVerifiers.hpp"
60 #include "utilities/bitMap.inline.hpp"
61 #include "utilities/copy.hpp"
62 #if INCLUDE_G1GC
63 #include "gc/g1/g1CollectedHeap.hpp"
64 #endif
65
66 #if INCLUDE_CDS_JAVA_HEAP
67
68 struct ArchivableStaticFieldInfo {
69 const char* klass_name;
70 const char* field_name;
71 InstanceKlass* klass;
72 int offset;
73 BasicType type;
74
75 ArchivableStaticFieldInfo(const char* k, const char* f)
76 : klass_name(k), field_name(f), klass(NULL), offset(0), type(T_ILLEGAL) {}
77
78 bool valid() {
79 return klass_name != NULL;
80 }
81 };
82
83 bool HeapShared::_disable_writing = false;
84 DumpedInternedStrings *HeapShared::_dumped_interned_strings = NULL;
85 GrowableArrayCHeap<Metadata**, mtClassShared>* HeapShared::_native_pointers = NULL;
86
87 #ifndef PRODUCT
88 #define ARCHIVE_TEST_FIELD_NAME "archivedObjects"
89 static Array<char>* _archived_ArchiveHeapTestClass = NULL;
90 static const char* _test_class_name = NULL;
91 static const Klass* _test_class = NULL;
92 static const ArchivedKlassSubGraphInfoRecord* _test_class_record = NULL;
93 #endif
94
95
96 //
97 // If you add new entries to the following tables, you should know what you're doing!
98 //
99
100 // Entry fields for shareable subgraphs archived in the closed archive heap
101 // region. Warning: Objects in the subgraphs should not have reference fields
102 // assigned at runtime.
103 static ArchivableStaticFieldInfo closed_archive_subgraph_entry_fields[] = {
104 {"java/lang/Integer$IntegerCache", "archivedCache"},
105 {"java/lang/Long$LongCache", "archivedCache"},
106 {"java/lang/Byte$ByteCache", "archivedCache"},
107 {"java/lang/Short$ShortCache", "archivedCache"},
108 {"java/lang/Character$CharacterCache", "archivedCache"},
109 {"java/util/jar/Attributes$Name", "KNOWN_NAMES"},
110 {"sun/util/locale/BaseLocale", "constantBaseLocales"},
111 {NULL, NULL},
112 };
113 // Entry fields for subgraphs archived in the open archive heap region.
114 static ArchivableStaticFieldInfo open_archive_subgraph_entry_fields[] = {
115 {"jdk/internal/module/ArchivedModuleGraph", "archivedModuleGraph"},
116 {"java/util/ImmutableCollections", "archivedObjects"},
117 {"java/lang/ModuleLayer", "EMPTY_LAYER"},
118 {"java/lang/module/Configuration", "EMPTY_CONFIGURATION"},
119 {"jdk/internal/math/FDBigInteger", "archivedCaches"},
120 #ifndef PRODUCT
121 {NULL, NULL}, // Extra slot for -XX:ArchiveHeapTestClass
122 #endif
123 {NULL, NULL},
124 };
125
126 // Entry fields for subgraphs archived in the open archive heap region (full module graph).
127 static ArchivableStaticFieldInfo fmg_open_archive_subgraph_entry_fields[] = {
128 {"jdk/internal/loader/ArchivedClassLoaders", "archivedClassLoaders"},
129 {"jdk/internal/module/ArchivedBootLayer", "archivedBootLayer"},
130 {"java/lang/Module$ArchivedData", "archivedData"},
131 {NULL, NULL},
132 };
133
134 GrowableArrayCHeap<oop, mtClassShared>* HeapShared::_pending_roots = NULL;
135 OopHandle HeapShared::_roots;
136
137 #ifdef ASSERT
138 bool HeapShared::is_archived_object_during_dumptime(oop p) {
139 assert(HeapShared::can_write(), "must be");
140 assert(DumpSharedSpaces, "this function is only used with -Xshare:dump");
141 return Universe::heap()->is_archived_object(p);
142 }
143 #endif
144
145 static bool is_subgraph_root_class_of(ArchivableStaticFieldInfo fields[], InstanceKlass* ik) {
146 for (int i = 0; fields[i].valid(); i++) {
147 if (fields[i].klass == ik) {
148 return true;
149 }
150 }
151 return false;
152 }
153
154 bool HeapShared::is_subgraph_root_class(InstanceKlass* ik) {
155 return is_subgraph_root_class_of(closed_archive_subgraph_entry_fields, ik) ||
156 is_subgraph_root_class_of(open_archive_subgraph_entry_fields, ik) ||
157 is_subgraph_root_class_of(fmg_open_archive_subgraph_entry_fields, ik);
158 }
159
160 unsigned HeapShared::oop_hash(oop const& p) {
161 // Do not call p->identity_hash() as that will update the
162 // object header.
163 return primitive_hash(cast_from_oop<intptr_t>(p));
164 }
165
166 static void reset_states(oop obj, TRAPS) {
167 Handle h_obj(THREAD, obj);
168 InstanceKlass* klass = InstanceKlass::cast(obj->klass());
169 TempNewSymbol method_name = SymbolTable::new_symbol("resetArchivedStates");
170 Symbol* method_sig = vmSymbols::void_method_signature();
171
172 while (klass != NULL) {
173 Method* method = klass->find_method(method_name, method_sig);
174 if (method != NULL) {
175 assert(method->is_private(), "must be");
176 if (log_is_enabled(Debug, cds)) {
177 ResourceMark rm(THREAD);
178 log_debug(cds)(" calling %s", method->name_and_sig_as_C_string());
179 }
180 JavaValue result(T_VOID);
181 JavaCalls::call_special(&result, h_obj, klass,
182 method_name, method_sig, CHECK);
183 }
184 klass = klass->java_super();
185 }
186 }
187
188 void HeapShared::reset_archived_object_states(TRAPS) {
189 assert(DumpSharedSpaces, "dump-time only");
190 log_debug(cds)("Resetting platform loader");
191 reset_states(SystemDictionary::java_platform_loader(), CHECK);
192 log_debug(cds)("Resetting system loader");
193 reset_states(SystemDictionary::java_system_loader(), CHECK);
194
195 // Clean up jdk.internal.loader.ClassLoaders::bootLoader(), which is not
196 // directly used for class loading, but rather is used by the core library
197 // to keep track of resources, etc, loaded by the null class loader.
198 //
199 // Note, this object is non-null, and is not the same as
200 // ClassLoaderData::the_null_class_loader_data()->class_loader(),
201 // which is null.
202 log_debug(cds)("Resetting boot loader");
203 JavaValue result(T_OBJECT);
204 JavaCalls::call_static(&result,
205 vmClasses::jdk_internal_loader_ClassLoaders_klass(),
206 vmSymbols::bootLoader_name(),
207 vmSymbols::void_BuiltinClassLoader_signature(),
208 CHECK);
209 Handle boot_loader(THREAD, result.get_oop());
210 reset_states(boot_loader(), CHECK);
211 }
212
213 HeapShared::ArchivedObjectCache* HeapShared::_archived_object_cache = NULL;
214 HeapShared::OriginalObjectTable* HeapShared::_original_object_table = NULL;
215 oop HeapShared::find_archived_heap_object(oop obj) {
216 assert(DumpSharedSpaces, "dump-time only");
217 ArchivedObjectCache* cache = archived_object_cache();
218 CachedOopInfo* p = cache->get(obj);
219 if (p != NULL) {
220 return p->_obj;
221 } else {
222 return NULL;
223 }
224 }
225
226 int HeapShared::append_root(oop obj) {
227 assert(DumpSharedSpaces, "dump-time only");
228
229 // No GC should happen since we aren't scanning _pending_roots.
230 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
231
232 if (_pending_roots == NULL) {
233 _pending_roots = new GrowableArrayCHeap<oop, mtClassShared>(500);
234 }
235
236 return _pending_roots->append(obj);
237 }
238
239 objArrayOop HeapShared::roots() {
240 if (DumpSharedSpaces) {
241 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
242 if (!HeapShared::can_write()) {
243 return NULL;
244 }
245 } else {
246 assert(UseSharedSpaces, "must be");
247 }
248
249 objArrayOop roots = (objArrayOop)_roots.resolve();
250 assert(roots != NULL, "should have been initialized");
251 return roots;
252 }
253
254 // Returns an objArray that contains all the roots of the archived objects
255 oop HeapShared::get_root(int index, bool clear) {
256 assert(index >= 0, "sanity");
257 if (DumpSharedSpaces) {
258 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
259 assert(_pending_roots != NULL, "sanity");
260 return _pending_roots->at(index);
261 } else {
262 assert(UseSharedSpaces, "must be");
263 assert(!_roots.is_empty(), "must have loaded shared heap");
264 oop result = roots()->obj_at(index);
265 if (clear) {
266 clear_root(index);
267 }
268 return result;
269 }
270 }
271
272 void HeapShared::clear_root(int index) {
273 assert(index >= 0, "sanity");
274 assert(UseSharedSpaces, "must be");
275 if (ArchiveHeapLoader::is_fully_available()) {
276 if (log_is_enabled(Debug, cds, heap)) {
277 oop old = roots()->obj_at(index);
278 log_debug(cds, heap)("Clearing root %d: was " PTR_FORMAT, index, p2i(old));
279 }
280 roots()->obj_at_put(index, NULL);
281 }
282 }
283
284 oop HeapShared::archive_object(oop obj) {
285 assert(DumpSharedSpaces, "dump-time only");
286
287 assert(!obj->is_stackChunk(), "do not archive stack chunks");
288
289 oop ao = find_archived_heap_object(obj);
290 if (ao != NULL) {
291 // already archived
292 return ao;
293 }
294
295 int len = obj->size();
296 if (G1CollectedHeap::heap()->is_archive_alloc_too_large(len)) {
297 log_debug(cds, heap)("Cannot archive, object (" PTR_FORMAT ") is too large: " SIZE_FORMAT,
298 p2i(obj), (size_t)obj->size());
299 return NULL;
300 }
301
302 oop archived_oop = cast_to_oop(G1CollectedHeap::heap()->archive_mem_allocate(len));
303 if (archived_oop != NULL) {
304 Copy::aligned_disjoint_words(cast_from_oop<HeapWord*>(obj), cast_from_oop<HeapWord*>(archived_oop), len);
305 // Reinitialize markword to remove age/marking/locking/etc.
306 //
307 // We need to retain the identity_hash, because it may have been used by some hashtables
308 // in the shared heap. This also has the side effect of pre-initializing the
309 // identity_hash for all shared objects, so they are less likely to be written
310 // into during run time, increasing the potential of memory sharing.
311 if (!(EnableValhalla && obj->mark().is_inline_type())) {
312 int hash_original = obj->identity_hash();
313 archived_oop->set_mark(archived_oop->klass()->prototype_header().copy_set_hash(hash_original));
314 assert(archived_oop->mark().is_unlocked(), "sanity");
315
316 DEBUG_ONLY(int hash_archived = archived_oop->identity_hash());
317 assert(hash_original == hash_archived, "Different hash codes: original %x, archived %x", hash_original, hash_archived);
318 }
319
320 ArchivedObjectCache* cache = archived_object_cache();
321 CachedOopInfo info = make_cached_oop_info(archived_oop);
322 cache->put(obj, info);
323 if (_original_object_table != NULL) {
324 _original_object_table->put(archived_oop, obj);
325 }
326 mark_native_pointers(obj, archived_oop);
327 if (log_is_enabled(Debug, cds, heap)) {
328 ResourceMark rm;
329 log_debug(cds, heap)("Archived heap object " PTR_FORMAT " ==> " PTR_FORMAT " : %s",
330 p2i(obj), p2i(archived_oop), obj->klass()->external_name());
331 }
332 } else {
333 log_error(cds, heap)(
334 "Cannot allocate space for object " PTR_FORMAT " in archived heap region",
335 p2i(obj));
336 log_error(cds)("Out of memory. Please run with a larger Java heap, current MaxHeapSize = "
337 SIZE_FORMAT "M", MaxHeapSize/M);
338 os::_exit(-1);
339 }
340 return archived_oop;
341 }
342
343 void HeapShared::archive_klass_objects() {
344 GrowableArray<Klass*>* klasses = ArchiveBuilder::current()->klasses();
345 assert(klasses != NULL, "sanity");
346 for (int i = 0; i < klasses->length(); i++) {
347 Klass* k = ArchiveBuilder::get_buffered_klass(klasses->at(i));
348
349 // archive mirror object
350 java_lang_Class::archive_mirror(k);
351
352 // archive the resolved_referenes array
353 if (k->is_instance_klass()) {
354 InstanceKlass* ik = InstanceKlass::cast(k);
355 ik->constants()->archive_resolved_references();
356 }
357 }
358 }
359
360 void HeapShared::mark_native_pointers(oop orig_obj, oop archived_obj) {
361 if (java_lang_Class::is_instance(orig_obj)) {
362 mark_one_native_pointer(archived_obj, java_lang_Class::klass_offset());
363 mark_one_native_pointer(archived_obj, java_lang_Class::array_klass_offset());
364 }
365 }
366
367 void HeapShared::mark_one_native_pointer(oop archived_obj, int offset) {
368 Metadata* ptr = archived_obj->metadata_field_acquire(offset);
369 if (ptr != NULL) {
370 // Set the native pointer to the requested address (at runtime, if the metadata
371 // is mapped at the default location, it will be at this address).
372 address buffer_addr = ArchiveBuilder::current()->get_buffered_addr((address)ptr);
373 address requested_addr = ArchiveBuilder::current()->to_requested(buffer_addr);
374 archived_obj->metadata_field_put(offset, (Metadata*)requested_addr);
375
376 // Remember this pointer. At runtime, if the metadata is mapped at a non-default
377 // location, the pointer needs to be patched (see ArchiveHeapLoader::patch_native_pointers()).
378 _native_pointers->append(archived_obj->field_addr<Metadata*>(offset));
379
380 log_debug(cds, heap, mirror)(
381 "Marked metadata field at %d: " PTR_FORMAT " ==> " PTR_FORMAT,
382 offset, p2i(ptr), p2i(requested_addr));
383 }
384 }
385
386 // -- Handling of Enum objects
387 // Java Enum classes have synthetic <clinit> methods that look like this
388 // enum MyEnum {FOO, BAR}
389 // MyEnum::<clinint> {
390 // /*static final MyEnum*/ MyEnum::FOO = new MyEnum("FOO");
391 // /*static final MyEnum*/ MyEnum::BAR = new MyEnum("BAR");
392 // }
393 //
394 // If MyEnum::FOO object is referenced by any of the archived subgraphs, we must
395 // ensure the archived value equals (in object address) to the runtime value of
396 // MyEnum::FOO.
397 //
398 // However, since MyEnum::<clinint> is synthetically generated by javac, there's
399 // no way of programmatically handling this inside the Java code (as you would handle
400 // ModuleLayer::EMPTY_LAYER, for example).
401 //
402 // Instead, we archive all static field of such Enum classes. At runtime,
403 // HeapShared::initialize_enum_klass() will skip the <clinit> method and pull
404 // the static fields out of the archived heap.
405 void HeapShared::check_enum_obj(int level,
406 KlassSubGraphInfo* subgraph_info,
407 oop orig_obj,
408 bool is_closed_archive) {
409 Klass* k = orig_obj->klass();
410 Klass* buffered_k = ArchiveBuilder::get_buffered_klass(k);
411 if (!k->is_instance_klass()) {
412 return;
413 }
414 InstanceKlass* ik = InstanceKlass::cast(k);
415 if (ik->java_super() == vmClasses::Enum_klass() && !ik->has_archived_enum_objs()) {
416 ResourceMark rm;
417 ik->set_has_archived_enum_objs();
418 buffered_k->set_has_archived_enum_objs();
419 oop mirror = ik->java_mirror();
420
421 for (JavaFieldStream fs(ik); !fs.done(); fs.next()) {
422 if (fs.access_flags().is_static()) {
423 fieldDescriptor& fd = fs.field_descriptor();
424 if (fd.field_type() != T_OBJECT && fd.field_type() != T_ARRAY) {
425 guarantee(false, "static field %s::%s must be T_OBJECT or T_ARRAY",
426 ik->external_name(), fd.name()->as_C_string());
427 }
428 oop oop_field = mirror->obj_field(fd.offset());
429 if (oop_field == NULL) {
430 guarantee(false, "static field %s::%s must not be null",
431 ik->external_name(), fd.name()->as_C_string());
432 } else if (oop_field->klass() != ik && oop_field->klass() != ik->array_klass_or_null()) {
433 guarantee(false, "static field %s::%s is of the wrong type",
434 ik->external_name(), fd.name()->as_C_string());
435 }
436 oop archived_oop_field = archive_reachable_objects_from(level, subgraph_info, oop_field, is_closed_archive);
437 int root_index = append_root(archived_oop_field);
438 log_info(cds, heap)("Archived enum obj @%d %s::%s (" INTPTR_FORMAT " -> " INTPTR_FORMAT ")",
439 root_index, ik->external_name(), fd.name()->as_C_string(),
440 p2i((oopDesc*)oop_field), p2i((oopDesc*)archived_oop_field));
441 SystemDictionaryShared::add_enum_klass_static_field(ik, root_index);
442 }
443 }
444 }
445 }
446
447 // See comments in HeapShared::check_enum_obj()
448 bool HeapShared::initialize_enum_klass(InstanceKlass* k, TRAPS) {
449 if (!ArchiveHeapLoader::is_fully_available()) {
450 return false;
451 }
452
453 RunTimeClassInfo* info = RunTimeClassInfo::get_for(k);
454 assert(info != NULL, "sanity");
455
456 if (log_is_enabled(Info, cds, heap)) {
457 ResourceMark rm;
458 log_info(cds, heap)("Initializing Enum class: %s", k->external_name());
459 }
460
461 oop mirror = k->java_mirror();
462 int i = 0;
463 for (JavaFieldStream fs(k); !fs.done(); fs.next()) {
464 if (fs.access_flags().is_static()) {
465 int root_index = info->enum_klass_static_field_root_index_at(i++);
466 fieldDescriptor& fd = fs.field_descriptor();
467 assert(fd.field_type() == T_OBJECT || fd.field_type() == T_ARRAY, "must be");
468 mirror->obj_field_put(fd.offset(), get_root(root_index, /*clear=*/true));
469 }
470 }
471 return true;
472 }
473
474 void HeapShared::run_full_gc_in_vm_thread() {
475 if (HeapShared::can_write()) {
476 // Avoid fragmentation while archiving heap objects.
477 // We do this inside a safepoint, so that no further allocation can happen after GC
478 // has finished.
479 if (GCLocker::is_active()) {
480 // Just checking for safety ...
481 // This should not happen during -Xshare:dump. If you see this, probably the Java core lib
482 // has been modified such that JNI code is executed in some clean up threads after
483 // we have finished class loading.
484 log_warning(cds)("GC locker is held, unable to start extra compacting GC. This may produce suboptimal results.");
485 } else {
486 log_info(cds)("Run GC ...");
487 Universe::heap()->collect_as_vm_thread(GCCause::_archive_time_gc);
488 log_info(cds)("Run GC done");
489 }
490 }
491 }
492
493 void HeapShared::archive_objects(GrowableArray<MemRegion>* closed_regions,
494 GrowableArray<MemRegion>* open_regions) {
495
496 G1HeapVerifier::verify_ready_for_archiving();
497
498 {
499 NoSafepointVerifier nsv;
500
501 // Cache for recording where the archived objects are copied to
502 create_archived_object_cache(log_is_enabled(Info, cds, map));
503
504 log_info(cds)("Heap range = [" PTR_FORMAT " - " PTR_FORMAT "]",
505 UseCompressedOops ? p2i(CompressedOops::begin()) :
506 p2i((address)G1CollectedHeap::heap()->reserved().start()),
507 UseCompressedOops ? p2i(CompressedOops::end()) :
508 p2i((address)G1CollectedHeap::heap()->reserved().end()));
509 log_info(cds)("Dumping objects to closed archive heap region ...");
510 copy_closed_objects(closed_regions);
511
512 log_info(cds)("Dumping objects to open archive heap region ...");
513 copy_open_objects(open_regions);
514
515 CDSHeapVerifier::verify();
516 }
517
518 G1HeapVerifier::verify_archive_regions();
519 }
520
521 void HeapShared::copy_closed_objects(GrowableArray<MemRegion>* closed_regions) {
522 assert(HeapShared::can_write(), "must be");
523
524 G1CollectedHeap::heap()->begin_archive_alloc_range();
525
526 // Archive interned string objects
527 StringTable::write_to_archive(_dumped_interned_strings);
528
529 archive_object_subgraphs(closed_archive_subgraph_entry_fields,
530 true /* is_closed_archive */,
531 false /* is_full_module_graph */);
532
533 G1CollectedHeap::heap()->end_archive_alloc_range(closed_regions,
534 os::vm_allocation_granularity());
535 }
536
537 void HeapShared::copy_open_objects(GrowableArray<MemRegion>* open_regions) {
538 assert(HeapShared::can_write(), "must be");
539
540 G1CollectedHeap::heap()->begin_archive_alloc_range(true /* open */);
541
542 java_lang_Class::archive_basic_type_mirrors();
543
544 archive_klass_objects();
545
546 archive_object_subgraphs(open_archive_subgraph_entry_fields,
547 false /* is_closed_archive */,
548 false /* is_full_module_graph */);
549 if (MetaspaceShared::use_full_module_graph()) {
550 archive_object_subgraphs(fmg_open_archive_subgraph_entry_fields,
551 false /* is_closed_archive */,
552 true /* is_full_module_graph */);
553 ClassLoaderDataShared::init_archived_oops();
554 }
555
556 copy_roots();
557
558 G1CollectedHeap::heap()->end_archive_alloc_range(open_regions,
559 os::vm_allocation_granularity());
560 }
561
562 // Copy _pending_archive_roots into an objArray
563 void HeapShared::copy_roots() {
564 // HeapShared::roots() points into an ObjArray in the open archive region. A portion of the
565 // objects in this array are discovered during HeapShared::archive_objects(). For example,
566 // in HeapShared::archive_reachable_objects_from() -> HeapShared::check_enum_obj().
567 // However, HeapShared::archive_objects() happens inside a safepoint, so we can't
568 // allocate a "regular" ObjArray and pass the result to HeapShared::archive_object().
569 // Instead, we have to roll our own alloc/copy routine here.
570 int length = _pending_roots != NULL ? _pending_roots->length() : 0;
571 size_t size = objArrayOopDesc::object_size(length);
572 Klass* k = Universe::objectArrayKlassObj(); // already relocated to point to archived klass
573 HeapWord* mem = G1CollectedHeap::heap()->archive_mem_allocate(size);
574
575 memset(mem, 0, size * BytesPerWord);
576 {
577 // This is copied from MemAllocator::finish
578 oopDesc::set_mark(mem, k->prototype_header());
579 oopDesc::release_set_klass(mem, k);
580 }
581 {
582 // This is copied from ObjArrayAllocator::initialize
583 arrayOopDesc::set_length(mem, length);
584 }
585
586 _roots = OopHandle(Universe::vm_global(), cast_to_oop(mem));
587 for (int i = 0; i < length; i++) {
588 roots()->obj_at_put(i, _pending_roots->at(i));
589 }
590 log_info(cds)("archived obj roots[%d] = " SIZE_FORMAT " words, klass = %p, obj = %p", length, size, k, mem);
591 }
592
593 //
594 // Subgraph archiving support
595 //
596 HeapShared::DumpTimeKlassSubGraphInfoTable* HeapShared::_dump_time_subgraph_info_table = NULL;
597 HeapShared::RunTimeKlassSubGraphInfoTable HeapShared::_run_time_subgraph_info_table;
598
599 // Get the subgraph_info for Klass k. A new subgraph_info is created if
600 // there is no existing one for k. The subgraph_info records the "buffered"
601 // address of the class.
602 KlassSubGraphInfo* HeapShared::init_subgraph_info(Klass* k, bool is_full_module_graph) {
603 assert(DumpSharedSpaces, "dump time only");
604 bool created;
605 Klass* buffered_k = ArchiveBuilder::get_buffered_klass(k);
606 KlassSubGraphInfo* info =
607 _dump_time_subgraph_info_table->put_if_absent(k, KlassSubGraphInfo(buffered_k, is_full_module_graph),
608 &created);
609 assert(created, "must not initialize twice");
610 return info;
611 }
612
613 KlassSubGraphInfo* HeapShared::get_subgraph_info(Klass* k) {
614 assert(DumpSharedSpaces, "dump time only");
615 KlassSubGraphInfo* info = _dump_time_subgraph_info_table->get(k);
616 assert(info != NULL, "must have been initialized");
617 return info;
618 }
619
620 // Add an entry field to the current KlassSubGraphInfo.
621 void KlassSubGraphInfo::add_subgraph_entry_field(
622 int static_field_offset, oop v, bool is_closed_archive) {
623 assert(DumpSharedSpaces, "dump time only");
624 if (_subgraph_entry_fields == NULL) {
625 _subgraph_entry_fields =
626 new(ResourceObj::C_HEAP, mtClass) GrowableArray<int>(10, mtClass);
627 }
628 _subgraph_entry_fields->append(static_field_offset);
629 _subgraph_entry_fields->append(HeapShared::append_root(v));
630 }
631
632 // Add the Klass* for an object in the current KlassSubGraphInfo's subgraphs.
633 // Only objects of boot classes can be included in sub-graph.
634 void KlassSubGraphInfo::add_subgraph_object_klass(Klass* orig_k) {
635 assert(DumpSharedSpaces, "dump time only");
636 Klass* buffered_k = ArchiveBuilder::get_buffered_klass(orig_k);
637
638 if (_subgraph_object_klasses == NULL) {
639 _subgraph_object_klasses =
640 new(ResourceObj::C_HEAP, mtClass) GrowableArray<Klass*>(50, mtClass);
641 }
642
643 assert(ArchiveBuilder::current()->is_in_buffer_space(buffered_k), "must be a shared class");
644
645 if (_k == buffered_k) {
646 // Don't add the Klass containing the sub-graph to it's own klass
647 // initialization list.
648 return;
649 }
650
651 if (buffered_k->is_instance_klass()) {
652 assert(InstanceKlass::cast(buffered_k)->is_shared_boot_class(),
653 "must be boot class");
654 // vmClasses::xxx_klass() are not updated, need to check
655 // the original Klass*
656 if (orig_k == vmClasses::String_klass() ||
657 orig_k == vmClasses::Object_klass()) {
658 // Initialized early during VM initialization. No need to be added
659 // to the sub-graph object class list.
660 return;
661 }
662 check_allowed_klass(InstanceKlass::cast(orig_k));
663 } else if (buffered_k->is_objArray_klass()) {
664 Klass* abk = ObjArrayKlass::cast(buffered_k)->bottom_klass();
665 if (abk->is_instance_klass()) {
666 assert(InstanceKlass::cast(abk)->is_shared_boot_class(),
667 "must be boot class");
668 check_allowed_klass(InstanceKlass::cast(ObjArrayKlass::cast(orig_k)->bottom_klass()));
669 }
670 if (buffered_k == Universe::objectArrayKlassObj()) {
671 // Initialized early during Universe::genesis. No need to be added
672 // to the list.
673 return;
674 }
675 } else {
676 assert(buffered_k->is_typeArray_klass(), "must be");
677 // Primitive type arrays are created early during Universe::genesis.
678 return;
679 }
680
681 if (log_is_enabled(Debug, cds, heap)) {
682 if (!_subgraph_object_klasses->contains(buffered_k)) {
683 ResourceMark rm;
684 log_debug(cds, heap)("Adding klass %s", orig_k->external_name());
685 }
686 }
687
688 _subgraph_object_klasses->append_if_missing(buffered_k);
689 _has_non_early_klasses |= is_non_early_klass(orig_k);
690 }
691
692 void KlassSubGraphInfo::check_allowed_klass(InstanceKlass* ik) {
693 if (ik->module()->name() == vmSymbols::java_base()) {
694 assert(ik->package() != NULL, "classes in java.base cannot be in unnamed package");
695 return;
696 }
697
698 #ifndef PRODUCT
699 if (!ik->module()->is_named() && ik->package() == NULL) {
700 // This class is loaded by ArchiveHeapTestClass
701 return;
702 }
703 const char* extra_msg = ", or in an unnamed package of an unnamed module";
704 #else
705 const char* extra_msg = "";
706 #endif
707
708 ResourceMark rm;
709 log_error(cds, heap)("Class %s not allowed in archive heap. Must be in java.base%s",
710 ik->external_name(), extra_msg);
711 os::_exit(1);
712 }
713
714 bool KlassSubGraphInfo::is_non_early_klass(Klass* k) {
715 if (k->is_objArray_klass()) {
716 k = ObjArrayKlass::cast(k)->bottom_klass();
717 }
718 if (k->is_instance_klass()) {
719 if (!SystemDictionaryShared::is_early_klass(InstanceKlass::cast(k))) {
720 ResourceMark rm;
721 log_info(cds, heap)("non-early: %s", k->external_name());
722 return true;
723 } else {
724 return false;
725 }
726 } else {
727 return false;
728 }
729 }
730
731 // Initialize an archived subgraph_info_record from the given KlassSubGraphInfo.
732 void ArchivedKlassSubGraphInfoRecord::init(KlassSubGraphInfo* info) {
733 _k = info->klass();
734 _entry_field_records = NULL;
735 _subgraph_object_klasses = NULL;
736 _is_full_module_graph = info->is_full_module_graph();
737
738 if (_is_full_module_graph) {
739 // Consider all classes referenced by the full module graph as early -- we will be
740 // allocating objects of these classes during JVMTI early phase, so they cannot
741 // be processed by (non-early) JVMTI ClassFileLoadHook
742 _has_non_early_klasses = false;
743 } else {
744 _has_non_early_klasses = info->has_non_early_klasses();
745 }
746
747 if (_has_non_early_klasses) {
748 ResourceMark rm;
749 log_info(cds, heap)(
750 "Subgraph of klass %s has non-early klasses and cannot be used when JVMTI ClassFileLoadHook is enabled",
751 _k->external_name());
752 }
753
754 // populate the entry fields
755 GrowableArray<int>* entry_fields = info->subgraph_entry_fields();
756 if (entry_fields != NULL) {
757 int num_entry_fields = entry_fields->length();
758 assert(num_entry_fields % 2 == 0, "sanity");
759 _entry_field_records =
760 ArchiveBuilder::new_ro_array<int>(num_entry_fields);
761 for (int i = 0 ; i < num_entry_fields; i++) {
762 _entry_field_records->at_put(i, entry_fields->at(i));
763 }
764 }
765
766 // the Klasses of the objects in the sub-graphs
767 GrowableArray<Klass*>* subgraph_object_klasses = info->subgraph_object_klasses();
768 if (subgraph_object_klasses != NULL) {
769 int num_subgraphs_klasses = subgraph_object_klasses->length();
770 _subgraph_object_klasses =
771 ArchiveBuilder::new_ro_array<Klass*>(num_subgraphs_klasses);
772 for (int i = 0; i < num_subgraphs_klasses; i++) {
773 Klass* subgraph_k = subgraph_object_klasses->at(i);
774 if (log_is_enabled(Info, cds, heap)) {
775 ResourceMark rm;
776 log_info(cds, heap)(
777 "Archived object klass %s (%2d) => %s",
778 _k->external_name(), i, subgraph_k->external_name());
779 }
780 _subgraph_object_klasses->at_put(i, subgraph_k);
781 ArchivePtrMarker::mark_pointer(_subgraph_object_klasses->adr_at(i));
782 }
783 }
784
785 ArchivePtrMarker::mark_pointer(&_k);
786 ArchivePtrMarker::mark_pointer(&_entry_field_records);
787 ArchivePtrMarker::mark_pointer(&_subgraph_object_klasses);
788 }
789
790 struct CopyKlassSubGraphInfoToArchive : StackObj {
791 CompactHashtableWriter* _writer;
792 CopyKlassSubGraphInfoToArchive(CompactHashtableWriter* writer) : _writer(writer) {}
793
794 bool do_entry(Klass* klass, KlassSubGraphInfo& info) {
795 if (info.subgraph_object_klasses() != NULL || info.subgraph_entry_fields() != NULL) {
796 ArchivedKlassSubGraphInfoRecord* record =
797 (ArchivedKlassSubGraphInfoRecord*)ArchiveBuilder::ro_region_alloc(sizeof(ArchivedKlassSubGraphInfoRecord));
798 record->init(&info);
799
800 Klass* buffered_k = ArchiveBuilder::get_buffered_klass(klass);
801 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary((address)buffered_k);
802 u4 delta = ArchiveBuilder::current()->any_to_offset_u4(record);
803 _writer->add(hash, delta);
804 }
805 return true; // keep on iterating
806 }
807 };
808
809 // Build the records of archived subgraph infos, which include:
810 // - Entry points to all subgraphs from the containing class mirror. The entry
811 // points are static fields in the mirror. For each entry point, the field
812 // offset, value and is_closed_archive flag are recorded in the sub-graph
813 // info. The value is stored back to the corresponding field at runtime.
814 // - A list of klasses that need to be loaded/initialized before archived
815 // java object sub-graph can be accessed at runtime.
816 void HeapShared::write_subgraph_info_table() {
817 // Allocate the contents of the hashtable(s) inside the RO region of the CDS archive.
818 DumpTimeKlassSubGraphInfoTable* d_table = _dump_time_subgraph_info_table;
819 CompactHashtableStats stats;
820
821 _run_time_subgraph_info_table.reset();
822
823 CompactHashtableWriter writer(d_table->_count, &stats);
824 CopyKlassSubGraphInfoToArchive copy(&writer);
825 d_table->iterate(©);
826 writer.dump(&_run_time_subgraph_info_table, "subgraphs");
827
828 #ifndef PRODUCT
829 if (ArchiveHeapTestClass != NULL) {
830 size_t len = strlen(ArchiveHeapTestClass) + 1;
831 Array<char>* array = ArchiveBuilder::new_ro_array<char>((int)len);
832 strncpy(array->adr_at(0), ArchiveHeapTestClass, len);
833 _archived_ArchiveHeapTestClass = array;
834 }
835 #endif
836 }
837
838 void HeapShared::serialize(SerializeClosure* soc) {
839 oop roots_oop = NULL;
840
841 if (soc->reading()) {
842 soc->do_oop(&roots_oop); // read from archive
843 assert(oopDesc::is_oop_or_null(roots_oop), "is oop");
844 // Create an OopHandle only if we have actually mapped or loaded the roots
845 if (roots_oop != NULL) {
846 assert(ArchiveHeapLoader::is_fully_available(), "must be");
847 _roots = OopHandle(Universe::vm_global(), roots_oop);
848 }
849 } else {
850 // writing
851 roots_oop = roots();
852 soc->do_oop(&roots_oop); // write to archive
853 }
854
855 #ifndef PRODUCT
856 soc->do_ptr((void**)&_archived_ArchiveHeapTestClass);
857 if (soc->reading() && _archived_ArchiveHeapTestClass != NULL) {
858 _test_class_name = _archived_ArchiveHeapTestClass->adr_at(0);
859 setup_test_class(_test_class_name);
860 }
861 #endif
862
863 _run_time_subgraph_info_table.serialize_header(soc);
864 }
865
866 static void verify_the_heap(Klass* k, const char* which) {
867 if (VerifyArchivedFields > 0) {
868 ResourceMark rm;
869 log_info(cds, heap)("Verify heap %s initializing static field(s) in %s",
870 which, k->external_name());
871
872 VM_Verify verify_op;
873 VMThread::execute(&verify_op);
874
875 if (VerifyArchivedFields > 1 && is_init_completed()) {
876 // At this time, the oop->klass() of some archived objects in the heap may not
877 // have been loaded into the system dictionary yet. Nevertheless, oop->klass() should
878 // have enough information (object size, oop maps, etc) so that a GC can be safely
879 // performed.
880 //
881 // -XX:VerifyArchivedFields=2 force a GC to happen in such an early stage
882 // to check for GC safety.
883 log_info(cds, heap)("Trigger GC %s initializing static field(s) in %s",
884 which, k->external_name());
885 FlagSetting fs1(VerifyBeforeGC, true);
886 FlagSetting fs2(VerifyDuringGC, true);
887 FlagSetting fs3(VerifyAfterGC, true);
888 Universe::heap()->collect(GCCause::_java_lang_system_gc);
889 }
890 }
891 }
892
893 // Before GC can execute, we must ensure that all oops reachable from HeapShared::roots()
894 // have a valid klass. I.e., oopDesc::klass() must have already been resolved.
895 //
896 // Note: if a ArchivedKlassSubGraphInfoRecord contains non-early classes, and JVMTI
897 // ClassFileLoadHook is enabled, it's possible for this class to be dynamically replaced. In
898 // this case, we will not load the ArchivedKlassSubGraphInfoRecord and will clear its roots.
899 void HeapShared::resolve_classes(JavaThread* current) {
900 assert(UseSharedSpaces, "runtime only!");
901 if (!ArchiveHeapLoader::is_fully_available()) {
902 return; // nothing to do
903 }
904 resolve_classes_for_subgraphs(current, closed_archive_subgraph_entry_fields);
905 resolve_classes_for_subgraphs(current, open_archive_subgraph_entry_fields);
906 resolve_classes_for_subgraphs(current, fmg_open_archive_subgraph_entry_fields);
907 }
908
909 void HeapShared::resolve_classes_for_subgraphs(JavaThread* current, ArchivableStaticFieldInfo fields[]) {
910 for (int i = 0; fields[i].valid(); i++) {
911 ArchivableStaticFieldInfo* info = &fields[i];
912 TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name);
913 InstanceKlass* k = SystemDictionaryShared::find_builtin_class(klass_name);
914 assert(k != NULL && k->is_shared_boot_class(), "sanity");
915 resolve_classes_for_subgraph_of(current, k);
916 }
917 }
918
919 void HeapShared::resolve_classes_for_subgraph_of(JavaThread* current, Klass* k) {
920 JavaThread* THREAD = current;
921 ExceptionMark em(THREAD);
922 const ArchivedKlassSubGraphInfoRecord* record =
923 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/false, THREAD);
924 if (HAS_PENDING_EXCEPTION) {
925 CLEAR_PENDING_EXCEPTION;
926 }
927 if (record == NULL) {
928 clear_archived_roots_of(k);
929 }
930 }
931
932 void HeapShared::initialize_from_archived_subgraph(JavaThread* current, Klass* k) {
933 JavaThread* THREAD = current;
934 if (!ArchiveHeapLoader::is_fully_available()) {
935 return; // nothing to do
936 }
937
938 ExceptionMark em(THREAD);
939 const ArchivedKlassSubGraphInfoRecord* record =
940 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/true, THREAD);
941
942 if (HAS_PENDING_EXCEPTION) {
943 CLEAR_PENDING_EXCEPTION;
944 // None of the field value will be set if there was an exception when initializing the classes.
945 // The java code will not see any of the archived objects in the
946 // subgraphs referenced from k in this case.
947 return;
948 }
949
950 if (record != NULL) {
951 init_archived_fields_for(k, record);
952 }
953 }
954
955 const ArchivedKlassSubGraphInfoRecord*
956 HeapShared::resolve_or_init_classes_for_subgraph_of(Klass* k, bool do_init, TRAPS) {
957 assert(!DumpSharedSpaces, "Should not be called with DumpSharedSpaces");
958
959 if (!k->is_shared()) {
960 return NULL;
961 }
962 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary_quick(k);
963 const ArchivedKlassSubGraphInfoRecord* record = _run_time_subgraph_info_table.lookup(k, hash, 0);
964
965 #ifndef PRODUCT
966 if (_test_class_name != NULL && k->name()->equals(_test_class_name) && record != NULL) {
967 _test_class = k;
968 _test_class_record = record;
969 }
970 #endif
971
972 // Initialize from archived data. Currently this is done only
973 // during VM initialization time. No lock is needed.
974 if (record != NULL) {
975 if (record->is_full_module_graph() && !MetaspaceShared::use_full_module_graph()) {
976 if (log_is_enabled(Info, cds, heap)) {
977 ResourceMark rm(THREAD);
978 log_info(cds, heap)("subgraph %s cannot be used because full module graph is disabled",
979 k->external_name());
980 }
981 return NULL;
982 }
983
984 if (record->has_non_early_klasses() && JvmtiExport::should_post_class_file_load_hook()) {
985 if (log_is_enabled(Info, cds, heap)) {
986 ResourceMark rm(THREAD);
987 log_info(cds, heap)("subgraph %s cannot be used because JVMTI ClassFileLoadHook is enabled",
988 k->external_name());
989 }
990 return NULL;
991 }
992
993 if (log_is_enabled(Info, cds, heap)) {
994 ResourceMark rm;
995 log_info(cds, heap)("%s subgraph %s ", do_init ? "init" : "resolve", k->external_name());
996 }
997
998 resolve_or_init(k, do_init, CHECK_NULL);
999
1000 // Load/link/initialize the klasses of the objects in the subgraph.
1001 // NULL class loader is used.
1002 Array<Klass*>* klasses = record->subgraph_object_klasses();
1003 if (klasses != NULL) {
1004 for (int i = 0; i < klasses->length(); i++) {
1005 Klass* klass = klasses->at(i);
1006 if (!klass->is_shared()) {
1007 return NULL;
1008 }
1009 resolve_or_init(klass, do_init, CHECK_NULL);
1010 }
1011 }
1012 }
1013
1014 return record;
1015 }
1016
1017 void HeapShared::resolve_or_init(Klass* k, bool do_init, TRAPS) {
1018 if (!do_init) {
1019 if (k->class_loader_data() == NULL) {
1020 Klass* resolved_k = SystemDictionary::resolve_or_null(k->name(), CHECK);
1021 assert(resolved_k == k, "classes used by archived heap must not be replaced by JVMTI ClassFileLoadHook");
1022 }
1023 } else {
1024 assert(k->class_loader_data() != NULL, "must have been resolved by HeapShared::resolve_classes");
1025 if (k->is_instance_klass()) {
1026 InstanceKlass* ik = InstanceKlass::cast(k);
1027 ik->initialize(CHECK);
1028 } else if (k->is_objArray_klass()) {
1029 ObjArrayKlass* oak = ObjArrayKlass::cast(k);
1030 oak->initialize(CHECK);
1031 }
1032 }
1033 }
1034
1035 void HeapShared::init_archived_fields_for(Klass* k, const ArchivedKlassSubGraphInfoRecord* record) {
1036 verify_the_heap(k, "before");
1037
1038 // Load the subgraph entry fields from the record and store them back to
1039 // the corresponding fields within the mirror.
1040 oop m = k->java_mirror();
1041 Array<int>* entry_field_records = record->entry_field_records();
1042 if (entry_field_records != NULL) {
1043 int efr_len = entry_field_records->length();
1044 assert(efr_len % 2 == 0, "sanity");
1045 for (int i = 0; i < efr_len; i += 2) {
1046 int field_offset = entry_field_records->at(i);
1047 int root_index = entry_field_records->at(i+1);
1048 oop v = get_root(root_index, /*clear=*/true);
1049 m->obj_field_put(field_offset, v);
1050 log_debug(cds, heap)(" " PTR_FORMAT " init field @ %2d = " PTR_FORMAT, p2i(k), field_offset, p2i(v));
1051 }
1052
1053 // Done. Java code can see the archived sub-graphs referenced from k's
1054 // mirror after this point.
1055 if (log_is_enabled(Info, cds, heap)) {
1056 ResourceMark rm;
1057 log_info(cds, heap)("initialize_from_archived_subgraph %s " PTR_FORMAT "%s",
1058 k->external_name(), p2i(k), JvmtiExport::is_early_phase() ? " (early)" : "");
1059 }
1060 }
1061
1062 verify_the_heap(k, "after ");
1063 }
1064
1065 void HeapShared::clear_archived_roots_of(Klass* k) {
1066 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary_quick(k);
1067 const ArchivedKlassSubGraphInfoRecord* record = _run_time_subgraph_info_table.lookup(k, hash, 0);
1068 if (record != NULL) {
1069 Array<int>* entry_field_records = record->entry_field_records();
1070 if (entry_field_records != NULL) {
1071 int efr_len = entry_field_records->length();
1072 assert(efr_len % 2 == 0, "sanity");
1073 for (int i = 0; i < efr_len; i += 2) {
1074 int root_index = entry_field_records->at(i+1);
1075 clear_root(root_index);
1076 }
1077 }
1078 }
1079 }
1080
1081 class WalkOopAndArchiveClosure: public BasicOopIterateClosure {
1082 int _level;
1083 bool _is_closed_archive;
1084 bool _record_klasses_only;
1085 KlassSubGraphInfo* _subgraph_info;
1086 oop _orig_referencing_obj;
1087 oop _archived_referencing_obj;
1088
1089 // The following are for maintaining a stack for determining
1090 // CachedOopInfo::_referrer
1091 static WalkOopAndArchiveClosure* _current;
1092 WalkOopAndArchiveClosure* _last;
1093 public:
1094 WalkOopAndArchiveClosure(int level,
1095 bool is_closed_archive,
1096 bool record_klasses_only,
1097 KlassSubGraphInfo* subgraph_info,
1098 oop orig, oop archived) :
1099 _level(level), _is_closed_archive(is_closed_archive),
1100 _record_klasses_only(record_klasses_only),
1101 _subgraph_info(subgraph_info),
1102 _orig_referencing_obj(orig), _archived_referencing_obj(archived) {
1103 _last = _current;
1104 _current = this;
1105 }
1106 ~WalkOopAndArchiveClosure() {
1107 _current = _last;
1108 }
1109 void do_oop(narrowOop *p) { WalkOopAndArchiveClosure::do_oop_work(p); }
1110 void do_oop( oop *p) { WalkOopAndArchiveClosure::do_oop_work(p); }
1111
1112 protected:
1113 template <class T> void do_oop_work(T *p) {
1114 oop obj = RawAccess<>::oop_load(p);
1115 if (!CompressedOops::is_null(obj)) {
1116 assert(!HeapShared::is_archived_object_during_dumptime(obj),
1117 "original objects must not point to archived objects");
1118
1119 size_t field_delta = pointer_delta(p, _orig_referencing_obj, sizeof(char));
1120 T* new_p = (T*)(cast_from_oop<address>(_archived_referencing_obj) + field_delta);
1121
1122 if (!_record_klasses_only && log_is_enabled(Debug, cds, heap)) {
1123 ResourceMark rm;
1124 log_debug(cds, heap)("(%d) %s[" SIZE_FORMAT "] ==> " PTR_FORMAT " size " SIZE_FORMAT " %s", _level,
1125 _orig_referencing_obj->klass()->external_name(), field_delta,
1126 p2i(obj), obj->size() * HeapWordSize, obj->klass()->external_name());
1127 LogTarget(Trace, cds, heap) log;
1128 LogStream out(log);
1129 obj->print_on(&out);
1130 }
1131
1132 oop archived = HeapShared::archive_reachable_objects_from(
1133 _level + 1, _subgraph_info, obj, _is_closed_archive);
1134 assert(archived != NULL, "VM should have exited with unarchivable objects for _level > 1");
1135 assert(HeapShared::is_archived_object_during_dumptime(archived), "must be");
1136
1137 if (!_record_klasses_only) {
1138 // Update the reference in the archived copy of the referencing object.
1139 log_debug(cds, heap)("(%d) updating oop @[" PTR_FORMAT "] " PTR_FORMAT " ==> " PTR_FORMAT,
1140 _level, p2i(new_p), p2i(obj), p2i(archived));
1141 RawAccess<IS_NOT_NULL>::oop_store(new_p, archived);
1142 }
1143 }
1144 }
1145
1146 public:
1147 static WalkOopAndArchiveClosure* current() { return _current; }
1148 oop orig_referencing_obj() { return _orig_referencing_obj; }
1149 KlassSubGraphInfo* subgraph_info() { return _subgraph_info; }
1150 };
1151
1152 WalkOopAndArchiveClosure* WalkOopAndArchiveClosure::_current = NULL;
1153
1154 HeapShared::CachedOopInfo HeapShared::make_cached_oop_info(oop orig_obj) {
1155 CachedOopInfo info;
1156 WalkOopAndArchiveClosure* walker = WalkOopAndArchiveClosure::current();
1157
1158 info._subgraph_info = (walker == NULL) ? NULL : walker->subgraph_info();
1159 info._referrer = (walker == NULL) ? NULL : walker->orig_referencing_obj();
1160 info._obj = orig_obj;
1161
1162 return info;
1163 }
1164
1165 void HeapShared::check_closed_region_object(InstanceKlass* k) {
1166 // Check fields in the object
1167 for (JavaFieldStream fs(k); !fs.done(); fs.next()) {
1168 if (!fs.access_flags().is_static()) {
1169 BasicType ft = fs.field_descriptor().field_type();
1170 if (!fs.access_flags().is_final() && is_reference_type(ft)) {
1171 ResourceMark rm;
1172 log_warning(cds, heap)(
1173 "Please check reference field in %s instance in closed archive heap region: %s %s",
1174 k->external_name(), (fs.name())->as_C_string(),
1175 (fs.signature())->as_C_string());
1176 }
1177 }
1178 }
1179 }
1180
1181 void HeapShared::check_module_oop(oop orig_module_obj) {
1182 assert(DumpSharedSpaces, "must be");
1183 assert(java_lang_Module::is_instance(orig_module_obj), "must be");
1184 ModuleEntry* orig_module_ent = java_lang_Module::module_entry_raw(orig_module_obj);
1185 if (orig_module_ent == NULL) {
1186 // These special Module objects are created in Java code. They are not
1187 // defined via Modules::define_module(), so they don't have a ModuleEntry:
1188 // java.lang.Module::ALL_UNNAMED_MODULE
1189 // java.lang.Module::EVERYONE_MODULE
1190 // jdk.internal.loader.ClassLoaders$BootClassLoader::unnamedModule
1191 assert(java_lang_Module::name(orig_module_obj) == NULL, "must be unnamed");
1192 log_info(cds, heap)("Module oop with No ModuleEntry* @[" PTR_FORMAT "]", p2i(orig_module_obj));
1193 } else {
1194 ClassLoaderData* loader_data = orig_module_ent->loader_data();
1195 assert(loader_data->is_builtin_class_loader_data(), "must be");
1196 }
1197 }
1198
1199
1200 // (1) If orig_obj has not been archived yet, archive it.
1201 // (2) If orig_obj has not been seen yet (since start_recording_subgraph() was called),
1202 // trace all objects that are reachable from it, and make sure these objects are archived.
1203 // (3) Record the klasses of all orig_obj and all reachable objects.
1204 oop HeapShared::archive_reachable_objects_from(int level,
1205 KlassSubGraphInfo* subgraph_info,
1206 oop orig_obj,
1207 bool is_closed_archive) {
1208 assert(orig_obj != NULL, "must be");
1209 assert(!is_archived_object_during_dumptime(orig_obj), "sanity");
1210
1211 if (!JavaClasses::is_supported_for_archiving(orig_obj)) {
1212 // This object has injected fields that cannot be supported easily, so we disallow them for now.
1213 // If you get an error here, you probably made a change in the JDK library that has added
1214 // these objects that are referenced (directly or indirectly) by static fields.
1215 ResourceMark rm;
1216 log_error(cds, heap)("Cannot archive object of class %s", orig_obj->klass()->external_name());
1217 os::_exit(1);
1218 }
1219
1220 // java.lang.Class instances cannot be included in an archived object sub-graph. We only support
1221 // them as Klass::_archived_mirror because they need to be specially restored at run time.
1222 //
1223 // If you get an error here, you probably made a change in the JDK library that has added a Class
1224 // object that is referenced (directly or indirectly) by static fields.
1225 if (java_lang_Class::is_instance(orig_obj)) {
1226 log_error(cds, heap)("(%d) Unknown java.lang.Class object is in the archived sub-graph", level);
1227 os::_exit(1);
1228 }
1229
1230 oop archived_obj = find_archived_heap_object(orig_obj);
1231 if (java_lang_String::is_instance(orig_obj) && archived_obj != NULL) {
1232 // To save time, don't walk strings that are already archived. They just contain
1233 // pointers to a type array, whose klass doesn't need to be recorded.
1234 return archived_obj;
1235 }
1236
1237 if (has_been_seen_during_subgraph_recording(orig_obj)) {
1238 // orig_obj has already been archived and traced. Nothing more to do.
1239 return archived_obj;
1240 } else {
1241 set_has_been_seen_during_subgraph_recording(orig_obj);
1242 }
1243
1244 bool record_klasses_only = (archived_obj != NULL);
1245 if (archived_obj == NULL) {
1246 ++_num_new_archived_objs;
1247 archived_obj = archive_object(orig_obj);
1248 if (archived_obj == NULL) {
1249 // Skip archiving the sub-graph referenced from the current entry field.
1250 ResourceMark rm;
1251 log_error(cds, heap)(
1252 "Cannot archive the sub-graph referenced from %s object ("
1253 PTR_FORMAT ") size " SIZE_FORMAT ", skipped.",
1254 orig_obj->klass()->external_name(), p2i(orig_obj), orig_obj->size() * HeapWordSize);
1255 if (level == 1) {
1256 // Don't archive a subgraph root that's too big. For archives static fields, that's OK
1257 // as the Java code will take care of initializing this field dynamically.
1258 return NULL;
1259 } else {
1260 // We don't know how to handle an object that has been archived, but some of its reachable
1261 // objects cannot be archived. Bail out for now. We might need to fix this in the future if
1262 // we have a real use case.
1263 os::_exit(1);
1264 }
1265 }
1266
1267 if (java_lang_Module::is_instance(orig_obj)) {
1268 check_module_oop(orig_obj);
1269 java_lang_Module::set_module_entry(archived_obj, NULL);
1270 java_lang_Module::set_loader(archived_obj, NULL);
1271 } else if (java_lang_ClassLoader::is_instance(orig_obj)) {
1272 // class_data will be restored explicitly at run time.
1273 guarantee(orig_obj == SystemDictionary::java_platform_loader() ||
1274 orig_obj == SystemDictionary::java_system_loader() ||
1275 java_lang_ClassLoader::loader_data(orig_obj) == NULL, "must be");
1276 java_lang_ClassLoader::release_set_loader_data(archived_obj, NULL);
1277 }
1278 }
1279
1280 assert(archived_obj != NULL, "must be");
1281 Klass *orig_k = orig_obj->klass();
1282 subgraph_info->add_subgraph_object_klass(orig_k);
1283
1284 WalkOopAndArchiveClosure walker(level, is_closed_archive, record_klasses_only,
1285 subgraph_info, orig_obj, archived_obj);
1286 orig_obj->oop_iterate(&walker);
1287 if (is_closed_archive && orig_k->is_instance_klass()) {
1288 check_closed_region_object(InstanceKlass::cast(orig_k));
1289 }
1290
1291 check_enum_obj(level + 1, subgraph_info, orig_obj, is_closed_archive);
1292 return archived_obj;
1293 }
1294
1295 //
1296 // Start from the given static field in a java mirror and archive the
1297 // complete sub-graph of java heap objects that are reached directly
1298 // or indirectly from the starting object by following references.
1299 // Sub-graph archiving restrictions (current):
1300 //
1301 // - All classes of objects in the archived sub-graph (including the
1302 // entry class) must be boot class only.
1303 // - No java.lang.Class instance (java mirror) can be included inside
1304 // an archived sub-graph. Mirror can only be the sub-graph entry object.
1305 //
1306 // The Java heap object sub-graph archiving process (see
1307 // WalkOopAndArchiveClosure):
1308 //
1309 // 1) Java object sub-graph archiving starts from a given static field
1310 // within a Class instance (java mirror). If the static field is a
1311 // reference field and points to a non-null java object, proceed to
1312 // the next step.
1313 //
1314 // 2) Archives the referenced java object. If an archived copy of the
1315 // current object already exists, updates the pointer in the archived
1316 // copy of the referencing object to point to the current archived object.
1317 // Otherwise, proceed to the next step.
1318 //
1319 // 3) Follows all references within the current java object and recursively
1320 // archive the sub-graph of objects starting from each reference.
1321 //
1322 // 4) Updates the pointer in the archived copy of referencing object to
1323 // point to the current archived object.
1324 //
1325 // 5) The Klass of the current java object is added to the list of Klasses
1326 // for loading and initializing before any object in the archived graph can
1327 // be accessed at runtime.
1328 //
1329 void HeapShared::archive_reachable_objects_from_static_field(InstanceKlass *k,
1330 const char* klass_name,
1331 int field_offset,
1332 const char* field_name,
1333 bool is_closed_archive) {
1334 assert(DumpSharedSpaces, "dump time only");
1335 assert(k->is_shared_boot_class(), "must be boot class");
1336
1337 oop m = k->java_mirror();
1338
1339 KlassSubGraphInfo* subgraph_info = get_subgraph_info(k);
1340 oop f = m->obj_field(field_offset);
1341
1342 log_debug(cds, heap)("Start archiving from: %s::%s (" PTR_FORMAT ")", klass_name, field_name, p2i(f));
1343
1344 if (!CompressedOops::is_null(f)) {
1345 if (log_is_enabled(Trace, cds, heap)) {
1346 LogTarget(Trace, cds, heap) log;
1347 LogStream out(log);
1348 f->print_on(&out);
1349 }
1350
1351 oop af = archive_reachable_objects_from(1, subgraph_info, f, is_closed_archive);
1352
1353 if (af == NULL) {
1354 log_error(cds, heap)("Archiving failed %s::%s (some reachable objects cannot be archived)",
1355 klass_name, field_name);
1356 } else {
1357 // Note: the field value is not preserved in the archived mirror.
1358 // Record the field as a new subGraph entry point. The recorded
1359 // information is restored from the archive at runtime.
1360 subgraph_info->add_subgraph_entry_field(field_offset, af, is_closed_archive);
1361 log_info(cds, heap)("Archived field %s::%s => " PTR_FORMAT, klass_name, field_name, p2i(af));
1362 }
1363 } else {
1364 // The field contains null, we still need to record the entry point,
1365 // so it can be restored at runtime.
1366 subgraph_info->add_subgraph_entry_field(field_offset, NULL, false);
1367 }
1368 }
1369
1370 #ifndef PRODUCT
1371 class VerifySharedOopClosure: public BasicOopIterateClosure {
1372 private:
1373 bool _is_archived;
1374
1375 public:
1376 VerifySharedOopClosure(bool is_archived) : _is_archived(is_archived) {}
1377
1378 void do_oop(narrowOop *p) { VerifySharedOopClosure::do_oop_work(p); }
1379 void do_oop( oop *p) { VerifySharedOopClosure::do_oop_work(p); }
1380
1381 protected:
1382 template <class T> void do_oop_work(T *p) {
1383 oop obj = RawAccess<>::oop_load(p);
1384 if (!CompressedOops::is_null(obj)) {
1385 HeapShared::verify_reachable_objects_from(obj, _is_archived);
1386 }
1387 }
1388 };
1389
1390 void HeapShared::verify_subgraph_from_static_field(InstanceKlass* k, int field_offset) {
1391 assert(DumpSharedSpaces, "dump time only");
1392 assert(k->is_shared_boot_class(), "must be boot class");
1393
1394 oop m = k->java_mirror();
1395 oop f = m->obj_field(field_offset);
1396 if (!CompressedOops::is_null(f)) {
1397 verify_subgraph_from(f);
1398 }
1399 }
1400
1401 void HeapShared::verify_subgraph_from(oop orig_obj) {
1402 oop archived_obj = find_archived_heap_object(orig_obj);
1403 if (archived_obj == NULL) {
1404 // It's OK for the root of a subgraph to be not archived. See comments in
1405 // archive_reachable_objects_from().
1406 return;
1407 }
1408
1409 // Verify that all objects reachable from orig_obj are archived.
1410 init_seen_objects_table();
1411 verify_reachable_objects_from(orig_obj, false);
1412 delete_seen_objects_table();
1413
1414 // Note: we could also verify that all objects reachable from the archived
1415 // copy of orig_obj can only point to archived objects, with:
1416 // init_seen_objects_table();
1417 // verify_reachable_objects_from(archived_obj, true);
1418 // init_seen_objects_table();
1419 // but that's already done in G1HeapVerifier::verify_archive_regions so we
1420 // won't do it here.
1421 }
1422
1423 void HeapShared::verify_reachable_objects_from(oop obj, bool is_archived) {
1424 _num_total_verifications ++;
1425 if (!has_been_seen_during_subgraph_recording(obj)) {
1426 set_has_been_seen_during_subgraph_recording(obj);
1427
1428 if (is_archived) {
1429 assert(is_archived_object_during_dumptime(obj), "must be");
1430 assert(find_archived_heap_object(obj) == NULL, "must be");
1431 } else {
1432 assert(!is_archived_object_during_dumptime(obj), "must be");
1433 assert(find_archived_heap_object(obj) != NULL, "must be");
1434 }
1435
1436 VerifySharedOopClosure walker(is_archived);
1437 obj->oop_iterate(&walker);
1438 }
1439 }
1440 #endif
1441
1442 HeapShared::SeenObjectsTable* HeapShared::_seen_objects_table = NULL;
1443 int HeapShared::_num_new_walked_objs;
1444 int HeapShared::_num_new_archived_objs;
1445 int HeapShared::_num_old_recorded_klasses;
1446
1447 int HeapShared::_num_total_subgraph_recordings = 0;
1448 int HeapShared::_num_total_walked_objs = 0;
1449 int HeapShared::_num_total_archived_objs = 0;
1450 int HeapShared::_num_total_recorded_klasses = 0;
1451 int HeapShared::_num_total_verifications = 0;
1452
1453 bool HeapShared::has_been_seen_during_subgraph_recording(oop obj) {
1454 return _seen_objects_table->get(obj) != NULL;
1455 }
1456
1457 void HeapShared::set_has_been_seen_during_subgraph_recording(oop obj) {
1458 assert(!has_been_seen_during_subgraph_recording(obj), "sanity");
1459 _seen_objects_table->put(obj, true);
1460 ++ _num_new_walked_objs;
1461 }
1462
1463 void HeapShared::start_recording_subgraph(InstanceKlass *k, const char* class_name, bool is_full_module_graph) {
1464 log_info(cds, heap)("Start recording subgraph(s) for archived fields in %s", class_name);
1465 init_subgraph_info(k, is_full_module_graph);
1466 init_seen_objects_table();
1467 _num_new_walked_objs = 0;
1468 _num_new_archived_objs = 0;
1469 _num_old_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses();
1470 }
1471
1472 void HeapShared::done_recording_subgraph(InstanceKlass *k, const char* class_name) {
1473 int num_new_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses() -
1474 _num_old_recorded_klasses;
1475 log_info(cds, heap)("Done recording subgraph(s) for archived fields in %s: "
1476 "walked %d objs, archived %d new objs, recorded %d classes",
1477 class_name, _num_new_walked_objs, _num_new_archived_objs,
1478 num_new_recorded_klasses);
1479
1480 delete_seen_objects_table();
1481
1482 _num_total_subgraph_recordings ++;
1483 _num_total_walked_objs += _num_new_walked_objs;
1484 _num_total_archived_objs += _num_new_archived_objs;
1485 _num_total_recorded_klasses += num_new_recorded_klasses;
1486 }
1487
1488 class ArchivableStaticFieldFinder: public FieldClosure {
1489 InstanceKlass* _ik;
1490 Symbol* _field_name;
1491 bool _found;
1492 int _offset;
1493 public:
1494 ArchivableStaticFieldFinder(InstanceKlass* ik, Symbol* field_name) :
1495 _ik(ik), _field_name(field_name), _found(false), _offset(-1) {}
1496
1497 virtual void do_field(fieldDescriptor* fd) {
1498 if (fd->name() == _field_name) {
1499 assert(!_found, "fields can never be overloaded");
1500 if (is_reference_type(fd->field_type())) {
1501 _found = true;
1502 _offset = fd->offset();
1503 }
1504 }
1505 }
1506 bool found() { return _found; }
1507 int offset() { return _offset; }
1508 };
1509
1510 void HeapShared::init_subgraph_entry_fields(ArchivableStaticFieldInfo fields[],
1511 TRAPS) {
1512 for (int i = 0; fields[i].valid(); i++) {
1513 ArchivableStaticFieldInfo* info = &fields[i];
1514 TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name);
1515 TempNewSymbol field_name = SymbolTable::new_symbol(info->field_name);
1516 ResourceMark rm; // for stringStream::as_string() etc.
1517
1518 #ifndef PRODUCT
1519 bool is_test_class = (ArchiveHeapTestClass != NULL) && (strcmp(info->klass_name, ArchiveHeapTestClass) == 0);
1520 #else
1521 bool is_test_class = false;
1522 #endif
1523
1524 if (is_test_class) {
1525 log_warning(cds)("Loading ArchiveHeapTestClass %s ...", ArchiveHeapTestClass);
1526 }
1527
1528 Klass* k = SystemDictionary::resolve_or_fail(klass_name, true, THREAD);
1529 if (HAS_PENDING_EXCEPTION) {
1530 CLEAR_PENDING_EXCEPTION;
1531 stringStream st;
1532 st.print("Fail to initialize archive heap: %s cannot be loaded by the boot loader", info->klass_name);
1533 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
1534 }
1535
1536 if (!k->is_instance_klass()) {
1537 stringStream st;
1538 st.print("Fail to initialize archive heap: %s is not an instance class", info->klass_name);
1539 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
1540 }
1541
1542 InstanceKlass* ik = InstanceKlass::cast(k);
1543 assert(InstanceKlass::cast(ik)->is_shared_boot_class(),
1544 "Only support boot classes");
1545
1546 if (is_test_class) {
1547 if (ik->module()->is_named()) {
1548 // We don't want ArchiveHeapTestClass to be abused to easily load/initialize arbitrary
1549 // core-lib classes. You need to at least append to the bootclasspath.
1550 stringStream st;
1551 st.print("ArchiveHeapTestClass %s is not in unnamed module", ArchiveHeapTestClass);
1552 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
1553 }
1554
1555 if (ik->package() != NULL) {
1556 // This restriction makes HeapShared::is_a_test_class_in_unnamed_module() easy.
1557 stringStream st;
1558 st.print("ArchiveHeapTestClass %s is not in unnamed package", ArchiveHeapTestClass);
1559 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
1560 }
1561 } else {
1562 if (ik->module()->name() != vmSymbols::java_base()) {
1563 // We don't want to deal with cases when a module is unavailable at runtime.
1564 // FUTURE -- load from archived heap only when module graph has not changed
1565 // between dump and runtime.
1566 stringStream st;
1567 st.print("%s is not in java.base module", info->klass_name);
1568 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
1569 }
1570 }
1571
1572 if (is_test_class) {
1573 log_warning(cds)("Initializing ArchiveHeapTestClass %s ...", ArchiveHeapTestClass);
1574 }
1575 ik->initialize(CHECK);
1576
1577 ArchivableStaticFieldFinder finder(ik, field_name);
1578 ik->do_local_static_fields(&finder);
1579 if (!finder.found()) {
1580 stringStream st;
1581 st.print("Unable to find the static T_OBJECT field %s::%s", info->klass_name, info->field_name);
1582 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
1583 }
1584
1585 info->klass = ik;
1586 info->offset = finder.offset();
1587 }
1588 }
1589
1590 void HeapShared::init_subgraph_entry_fields(TRAPS) {
1591 assert(HeapShared::can_write(), "must be");
1592 _dump_time_subgraph_info_table = new (ResourceObj::C_HEAP, mtClass)DumpTimeKlassSubGraphInfoTable();
1593 init_subgraph_entry_fields(closed_archive_subgraph_entry_fields, CHECK);
1594 init_subgraph_entry_fields(open_archive_subgraph_entry_fields, CHECK);
1595 if (MetaspaceShared::use_full_module_graph()) {
1596 init_subgraph_entry_fields(fmg_open_archive_subgraph_entry_fields, CHECK);
1597 }
1598 }
1599
1600 #ifndef PRODUCT
1601 void HeapShared::setup_test_class(const char* test_class_name) {
1602 ArchivableStaticFieldInfo* p = open_archive_subgraph_entry_fields;
1603 int num_slots = sizeof(open_archive_subgraph_entry_fields) / sizeof(ArchivableStaticFieldInfo);
1604 assert(p[num_slots - 2].klass_name == NULL, "must have empty slot that's patched below");
1605 assert(p[num_slots - 1].klass_name == NULL, "must have empty slot that marks the end of the list");
1606
1607 if (test_class_name != NULL) {
1608 p[num_slots - 2].klass_name = test_class_name;
1609 p[num_slots - 2].field_name = ARCHIVE_TEST_FIELD_NAME;
1610 }
1611 }
1612
1613 // See if ik is one of the test classes that are pulled in by -XX:ArchiveHeapTestClass
1614 // during runtime. This may be called before the module system is initialized so
1615 // we cannot rely on InstanceKlass::module(), etc.
1616 bool HeapShared::is_a_test_class_in_unnamed_module(Klass* ik) {
1617 if (_test_class != NULL) {
1618 if (ik == _test_class) {
1619 return true;
1620 }
1621 Array<Klass*>* klasses = _test_class_record->subgraph_object_klasses();
1622 if (klasses == NULL) {
1623 return false;
1624 }
1625
1626 for (int i = 0; i < klasses->length(); i++) {
1627 Klass* k = klasses->at(i);
1628 if (k == ik) {
1629 Symbol* name;
1630 if (k->is_instance_klass()) {
1631 name = InstanceKlass::cast(k)->name();
1632 } else if (k->is_objArray_klass()) {
1633 Klass* bk = ObjArrayKlass::cast(k)->bottom_klass();
1634 if (!bk->is_instance_klass()) {
1635 return false;
1636 }
1637 name = bk->name();
1638 } else {
1639 return false;
1640 }
1641
1642 // See KlassSubGraphInfo::check_allowed_klass() - only two types of
1643 // classes are allowed:
1644 // (A) java.base classes (which must not be in the unnamed module)
1645 // (B) test classes which must be in the unnamed package of the unnamed module.
1646 // So if we see a '/' character in the class name, it must be in (A);
1647 // otherwise it must be in (B).
1648 if (name->index_of_at(0, "/", 1) >= 0) {
1649 return false; // (A)
1650 }
1651
1652 return true; // (B)
1653 }
1654 }
1655 }
1656
1657 return false;
1658 }
1659 #endif
1660
1661 void HeapShared::init_for_dumping(TRAPS) {
1662 if (HeapShared::can_write()) {
1663 setup_test_class(ArchiveHeapTestClass);
1664 _dumped_interned_strings = new (ResourceObj::C_HEAP, mtClass)DumpedInternedStrings();
1665 _native_pointers = new GrowableArrayCHeap<Metadata**, mtClassShared>(2048);
1666 init_subgraph_entry_fields(CHECK);
1667 }
1668 }
1669
1670 void HeapShared::archive_object_subgraphs(ArchivableStaticFieldInfo fields[],
1671 bool is_closed_archive,
1672 bool is_full_module_graph) {
1673 _num_total_subgraph_recordings = 0;
1674 _num_total_walked_objs = 0;
1675 _num_total_archived_objs = 0;
1676 _num_total_recorded_klasses = 0;
1677 _num_total_verifications = 0;
1678
1679 // For each class X that has one or more archived fields:
1680 // [1] Dump the subgraph of each archived field
1681 // [2] Create a list of all the class of the objects that can be reached
1682 // by any of these static fields.
1683 // At runtime, these classes are initialized before X's archived fields
1684 // are restored by HeapShared::initialize_from_archived_subgraph().
1685 int i;
1686 for (int i = 0; fields[i].valid(); ) {
1687 ArchivableStaticFieldInfo* info = &fields[i];
1688 const char* klass_name = info->klass_name;
1689 start_recording_subgraph(info->klass, klass_name, is_full_module_graph);
1690
1691 // If you have specified consecutive fields of the same klass in
1692 // fields[], these will be archived in the same
1693 // {start_recording_subgraph ... done_recording_subgraph} pass to
1694 // save time.
1695 for (; fields[i].valid(); i++) {
1696 ArchivableStaticFieldInfo* f = &fields[i];
1697 if (f->klass_name != klass_name) {
1698 break;
1699 }
1700
1701 archive_reachable_objects_from_static_field(f->klass, f->klass_name,
1702 f->offset, f->field_name,
1703 is_closed_archive);
1704 }
1705 done_recording_subgraph(info->klass, klass_name);
1706 }
1707
1708 log_info(cds, heap)("Archived subgraph records in %s archive heap region = %d",
1709 is_closed_archive ? "closed" : "open",
1710 _num_total_subgraph_recordings);
1711 log_info(cds, heap)(" Walked %d objects", _num_total_walked_objs);
1712 log_info(cds, heap)(" Archived %d objects", _num_total_archived_objs);
1713 log_info(cds, heap)(" Recorded %d klasses", _num_total_recorded_klasses);
1714
1715 #ifndef PRODUCT
1716 for (int i = 0; fields[i].valid(); i++) {
1717 ArchivableStaticFieldInfo* f = &fields[i];
1718 verify_subgraph_from_static_field(f->klass, f->offset);
1719 }
1720 log_info(cds, heap)(" Verified %d references", _num_total_verifications);
1721 #endif
1722 }
1723
1724 // Not all the strings in the global StringTable are dumped into the archive, because
1725 // some of those strings may be only referenced by classes that are excluded from
1726 // the archive. We need to explicitly mark the strings that are:
1727 // [1] used by classes that WILL be archived;
1728 // [2] included in the SharedArchiveConfigFile.
1729 void HeapShared::add_to_dumped_interned_strings(oop string) {
1730 assert_at_safepoint(); // DumpedInternedStrings uses raw oops
1731 bool created;
1732 _dumped_interned_strings->put_if_absent(string, true, &created);
1733 }
1734
1735 // At dump-time, find the location of all the non-null oop pointers in an archived heap
1736 // region. This way we can quickly relocate all the pointers without using
1737 // BasicOopIterateClosure at runtime.
1738 class FindEmbeddedNonNullPointers: public BasicOopIterateClosure {
1739 void* _start;
1740 BitMap *_oopmap;
1741 int _num_total_oops;
1742 int _num_null_oops;
1743 public:
1744 FindEmbeddedNonNullPointers(void* start, BitMap* oopmap)
1745 : _start(start), _oopmap(oopmap), _num_total_oops(0), _num_null_oops(0) {}
1746
1747 virtual void do_oop(narrowOop* p) {
1748 assert(UseCompressedOops, "sanity");
1749 _num_total_oops ++;
1750 narrowOop v = *p;
1751 if (!CompressedOops::is_null(v)) {
1752 // Note: HeapShared::to_requested_address() is not necessary because
1753 // the heap always starts at a deterministic address with UseCompressedOops==true.
1754 size_t idx = p - (narrowOop*)_start;
1755 _oopmap->set_bit(idx);
1756 } else {
1757 _num_null_oops ++;
1758 }
1759 }
1760 virtual void do_oop(oop* p) {
1761 assert(!UseCompressedOops, "sanity");
1762 _num_total_oops ++;
1763 if ((*p) != NULL) {
1764 size_t idx = p - (oop*)_start;
1765 _oopmap->set_bit(idx);
1766 if (DumpSharedSpaces) {
1767 // Make heap content deterministic.
1768 *p = HeapShared::to_requested_address(*p);
1769 }
1770 } else {
1771 _num_null_oops ++;
1772 }
1773 }
1774 int num_total_oops() const { return _num_total_oops; }
1775 int num_null_oops() const { return _num_null_oops; }
1776 };
1777
1778
1779 address HeapShared::to_requested_address(address dumptime_addr) {
1780 assert(DumpSharedSpaces, "static dump time only");
1781 if (dumptime_addr == NULL || UseCompressedOops) {
1782 return dumptime_addr;
1783 }
1784
1785 // With UseCompressedOops==false, actual_base is selected by the OS so
1786 // it's different across -Xshare:dump runs.
1787 address actual_base = (address)G1CollectedHeap::heap()->reserved().start();
1788 address actual_end = (address)G1CollectedHeap::heap()->reserved().end();
1789 assert(actual_base <= dumptime_addr && dumptime_addr <= actual_end, "must be an address in the heap");
1790
1791 // We always write the objects as if the heap started at this address. This
1792 // makes the heap content deterministic.
1793 //
1794 // Note that at runtime, the heap address is also selected by the OS, so
1795 // the archive heap will not be mapped at 0x10000000. Instead, we will call
1796 // HeapShared::patch_embedded_pointers() to relocate the heap contents
1797 // accordingly.
1798 const address REQUESTED_BASE = (address)0x10000000;
1799 intx delta = REQUESTED_BASE - actual_base;
1800
1801 address requested_addr = dumptime_addr + delta;
1802 assert(REQUESTED_BASE != 0 && requested_addr != NULL, "sanity");
1803 return requested_addr;
1804 }
1805
1806 ResourceBitMap HeapShared::calculate_oopmap(MemRegion region) {
1807 size_t num_bits = region.byte_size() / (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop));
1808 ResourceBitMap oopmap(num_bits);
1809
1810 HeapWord* p = region.start();
1811 HeapWord* end = region.end();
1812 FindEmbeddedNonNullPointers finder((void*)p, &oopmap);
1813 ArchiveBuilder* builder = DumpSharedSpaces ? ArchiveBuilder::current() : NULL;
1814
1815 int num_objs = 0;
1816 while (p < end) {
1817 oop o = cast_to_oop(p);
1818 o->oop_iterate(&finder);
1819 p += o->size();
1820 if (DumpSharedSpaces) {
1821 builder->relocate_klass_ptr_of_oop(o);
1822 }
1823 ++ num_objs;
1824 }
1825
1826 log_info(cds, heap)("calculate_oopmap: objects = %6d, oop fields = %7d (nulls = %7d)",
1827 num_objs, finder.num_total_oops(), finder.num_null_oops());
1828 return oopmap;
1829 }
1830
1831
1832 ResourceBitMap HeapShared::calculate_ptrmap(MemRegion region) {
1833 size_t num_bits = region.byte_size() / sizeof(Metadata*);
1834 ResourceBitMap oopmap(num_bits);
1835
1836 Metadata** start = (Metadata**)region.start();
1837 Metadata** end = (Metadata**)region.end();
1838
1839 int num_non_null_ptrs = 0;
1840 int len = _native_pointers->length();
1841 for (int i = 0; i < len; i++) {
1842 Metadata** p = _native_pointers->at(i);
1843 if (start <= p && p < end) {
1844 assert(*p != NULL, "must be non-null");
1845 num_non_null_ptrs ++;
1846 size_t idx = p - start;
1847 oopmap.set_bit(idx);
1848 }
1849 }
1850
1851 log_info(cds, heap)("calculate_ptrmap: marked %d non-null native pointers out of "
1852 SIZE_FORMAT " possible locations", num_non_null_ptrs, num_bits);
1853 if (num_non_null_ptrs > 0) {
1854 return oopmap;
1855 } else {
1856 return ResourceBitMap(0);
1857 }
1858 }
1859
1860 #endif // INCLUDE_CDS_JAVA_HEAP