1 /*
2 * Copyright (c) 2018, 2026, 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 "cds/aotArtifactFinder.hpp"
26 #include "cds/aotClassInitializer.hpp"
27 #include "cds/aotClassLocation.hpp"
28 #include "cds/aotCompressedPointers.hpp"
29 #include "cds/aotLogging.hpp"
30 #include "cds/aotMappedHeapLoader.hpp"
31 #include "cds/aotMappedHeapWriter.hpp"
32 #include "cds/aotMetaspace.hpp"
33 #include "cds/aotOopChecker.hpp"
34 #include "cds/aotReferenceObjSupport.hpp"
35 #include "cds/aotStreamedHeapLoader.hpp"
36 #include "cds/aotStreamedHeapWriter.hpp"
37 #include "cds/archiveBuilder.hpp"
38 #include "cds/archiveUtils.hpp"
39 #include "cds/cds_globals.hpp"
40 #include "cds/cdsConfig.hpp"
41 #include "cds/cdsEnumKlass.hpp"
42 #include "cds/cdsHeapVerifier.hpp"
43 #include "cds/heapShared.inline.hpp"
44 #include "cds/regeneratedClasses.hpp"
45 #include "classfile/classLoaderData.hpp"
46 #include "classfile/javaClasses.inline.hpp"
47 #include "classfile/modules.hpp"
48 #include "classfile/stringTable.hpp"
49 #include "classfile/symbolTable.hpp"
50 #include "classfile/systemDictionary.hpp"
51 #include "classfile/systemDictionaryShared.hpp"
52 #include "classfile/vmClasses.hpp"
53 #include "classfile/vmSymbols.hpp"
54 #include "gc/shared/collectedHeap.hpp"
55 #include "gc/shared/gcLocker.hpp"
56 #include "gc/shared/gcVMOperations.hpp"
57 #include "logging/log.hpp"
58 #include "logging/logStream.hpp"
59 #include "memory/iterator.inline.hpp"
60 #include "memory/resourceArea.hpp"
61 #include "memory/universe.hpp"
62 #include "oops/compressedOops.inline.hpp"
63 #include "oops/fieldStreams.inline.hpp"
64 #include "oops/objArrayOop.inline.hpp"
65 #include "oops/oop.inline.hpp"
66 #include "oops/oopHandle.inline.hpp"
67 #include "oops/typeArrayOop.inline.hpp"
68 #include "prims/jvmtiExport.hpp"
69 #include "runtime/arguments.hpp"
70 #include "runtime/fieldDescriptor.inline.hpp"
71 #include "runtime/globals_extension.hpp"
72 #include "runtime/init.hpp"
73 #include "runtime/javaCalls.hpp"
74 #include "runtime/mutexLocker.hpp"
75 #include "runtime/safepointVerifiers.hpp"
76 #include "utilities/bitMap.inline.hpp"
77 #include "utilities/copy.hpp"
78 #if INCLUDE_G1GC
79 #include "gc/g1/g1CollectedHeap.hpp"
80 #endif
81
82 #if INCLUDE_CDS_JAVA_HEAP
83
84 struct ArchivableStaticFieldInfo {
85 const char* klass_name;
86 const char* field_name;
87 InstanceKlass* klass;
88 int offset;
89 BasicType type;
90
91 ArchivableStaticFieldInfo(const char* k, const char* f)
92 : klass_name(k), field_name(f), klass(nullptr), offset(0), type(T_ILLEGAL) {}
93
94 bool valid() {
95 return klass_name != nullptr;
96 }
97 };
98
99 HeapArchiveMode HeapShared::_heap_load_mode = HeapArchiveMode::_uninitialized;
100 HeapArchiveMode HeapShared::_heap_write_mode = HeapArchiveMode::_uninitialized;
101
102 size_t HeapShared::_alloc_count[HeapShared::ALLOC_STAT_SLOTS];
103 size_t HeapShared::_alloc_size[HeapShared::ALLOC_STAT_SLOTS];
104 size_t HeapShared::_total_obj_count;
105 size_t HeapShared::_total_obj_size;
106
107 #ifndef PRODUCT
108 #define ARCHIVE_TEST_FIELD_NAME "archivedObjects"
109 static Array<char>* _archived_ArchiveHeapTestClass = nullptr;
110 static const char* _test_class_name = nullptr;
111 static Klass* _test_class = nullptr;
112 static const ArchivedKlassSubGraphInfoRecord* _test_class_record = nullptr;
113 #endif
114
115
116 //
117 // If you add new entries to the following tables, you should know what you're doing!
118 //
119
120 static ArchivableStaticFieldInfo archive_subgraph_entry_fields[] = {
121 {"java/lang/Integer$IntegerCache", "archivedCache"},
122 {"java/lang/Long$LongCache", "archivedCache"},
123 {"java/lang/Byte$ByteCache", "archivedCache"},
124 {"java/lang/Short$ShortCache", "archivedCache"},
125 {"java/lang/Character$CharacterCache", "archivedCache"},
126 {"java/util/jar/Attributes$Name", "KNOWN_NAMES"},
127 {"sun/util/locale/BaseLocale", "constantBaseLocales"},
128 {"jdk/internal/module/ArchivedModuleGraph", "archivedModuleGraph"},
129 {"java/util/ImmutableCollections", "archivedObjects"},
130 {"java/lang/ModuleLayer", "EMPTY_LAYER"},
131 {"java/lang/module/Configuration", "EMPTY_CONFIGURATION"},
132 {"jdk/internal/math/FDBigInteger", "archivedCaches"},
133
134 #ifndef PRODUCT
135 {nullptr, nullptr}, // Extra slot for -XX:ArchiveHeapTestClass
136 #endif
137 {nullptr, nullptr},
138 };
139
140 // full module graph
141 static ArchivableStaticFieldInfo fmg_archive_subgraph_entry_fields[] = {
142 {"jdk/internal/loader/ArchivedClassLoaders", "archivedClassLoaders"},
143 {ARCHIVED_BOOT_LAYER_CLASS, ARCHIVED_BOOT_LAYER_FIELD},
144 {"java/lang/Module$ArchivedData", "archivedData"},
145 {nullptr, nullptr},
146 };
147
148 KlassSubGraphInfo* HeapShared::_dump_time_special_subgraph;
149 ArchivedKlassSubGraphInfoRecord* HeapShared::_run_time_special_subgraph;
150 GrowableArrayCHeap<oop, mtClassShared>* HeapShared::_pending_roots = nullptr;
151 OopHandle HeapShared::_scratch_basic_type_mirrors[T_VOID+1];
152 MetaspaceObjToOopHandleTable* HeapShared::_scratch_objects_table = nullptr;
153
154 static bool is_subgraph_root_class_of(ArchivableStaticFieldInfo fields[], InstanceKlass* ik) {
155 for (int i = 0; fields[i].valid(); i++) {
156 if (fields[i].klass == ik) {
157 return true;
158 }
159 }
160 return false;
161 }
162
163 bool HeapShared::is_subgraph_root_class(InstanceKlass* ik) {
164 assert(CDSConfig::is_dumping_heap(), "dump-time only");
165 if (CDSConfig::is_dumping_klass_subgraphs()) {
166 // Legacy CDS archive support (to be deprecated)
167 return is_subgraph_root_class_of(archive_subgraph_entry_fields, ik) ||
168 is_subgraph_root_class_of(fmg_archive_subgraph_entry_fields, ik);
169 } else {
170 return false;
171 }
172 }
173
174 oop HeapShared::CachedOopInfo::orig_referrer() const {
175 return _orig_referrer.resolve();
176 }
177
178 // This is a simple hashing of the oop's address. This function is used
179 // while copying the oops into the AOT heap region. We don't want to
180 // have any side effects during the copying, so we avoid calling
181 // p->identity_hash() which can update the object header.
182 unsigned HeapShared::oop_address_hash(oop const& p) {
183 assert(SafepointSynchronize::is_at_safepoint() ||
184 JavaThread::current()->is_in_no_safepoint_scope(), "sanity");
185 return primitive_hash(cast_from_oop<intptr_t>(p));
186 }
187
188 // About the hashcode in the cached objects:
189 // - If a source object has a hashcode, it must be copied into the cache.
190 // That's because some cached hashtables are laid out using this hashcode.
191 // - If a source object doesn't have a hashcode, we avoid computing it while
192 // copying the objects into the cache. This will allow the hashcode to be
193 // dynamically and randomly computed in each production, which generally
194 // desirable to make the hashcodes more random between runs.
195 unsigned HeapShared::archived_object_cache_hash(OopHandle const& oh) {
196 oop o = oh.resolve();
197 if (o == nullptr) {
198 return 0;
199 }
200 if (!_use_identity_hash_for_archived_object_cache) {
201 // This is called while we are copying the objects. Don't call o->identity_hash()
202 // as that will update the object header.
203 return oop_address_hash(o);
204 } else {
205 // This is called after all objects are copied. It's OK to update
206 // the object's hashcode.
207 //
208 // This may be called after we have left the AOT dumping safepoint.
209 // Objects in archived_object_cache() may be moved by the GC, so we
210 // can't use the address of o for computing the hash.
211 return o->identity_hash();
212 }
213 }
214
215 bool HeapShared::oop_handle_equals(const OopHandle& a, const OopHandle& b) {
216 return a.resolve() == b.resolve();
217 }
218
219 static void reset_states(oop obj, TRAPS) {
220 Handle h_obj(THREAD, obj);
221 InstanceKlass* klass = InstanceKlass::cast(obj->klass());
222 TempNewSymbol method_name = SymbolTable::new_symbol("resetArchivedStates");
223 Symbol* method_sig = vmSymbols::void_method_signature();
224
225 while (klass != nullptr) {
226 Method* method = klass->find_method(method_name, method_sig);
227 if (method != nullptr) {
228 assert(method->is_private(), "must be");
229 if (log_is_enabled(Debug, aot)) {
230 ResourceMark rm(THREAD);
231 log_debug(aot)(" calling %s", method->name_and_sig_as_C_string());
232 }
233 JavaValue result(T_VOID);
234 JavaCalls::call_special(&result, h_obj, klass,
235 method_name, method_sig, CHECK);
236 }
237 klass = klass->super();
238 }
239 }
240
241 void HeapShared::reset_archived_object_states(TRAPS) {
242 assert(CDSConfig::is_dumping_heap(), "dump-time only");
243 log_debug(aot)("Resetting platform loader");
244 reset_states(SystemDictionary::java_platform_loader(), CHECK);
245 log_debug(aot)("Resetting system loader");
246 reset_states(SystemDictionary::java_system_loader(), CHECK);
247
248 // Clean up jdk.internal.loader.ClassLoaders::bootLoader(), which is not
249 // directly used for class loading, but rather is used by the core library
250 // to keep track of resources, etc, loaded by the null class loader.
251 //
252 // Note, this object is non-null, and is not the same as
253 // ClassLoaderData::the_null_class_loader_data()->class_loader(),
254 // which is null.
255 log_debug(aot)("Resetting boot loader");
256 JavaValue result(T_OBJECT);
257 JavaCalls::call_static(&result,
258 vmClasses::jdk_internal_loader_ClassLoaders_klass(),
259 vmSymbols::bootLoader_name(),
260 vmSymbols::void_BuiltinClassLoader_signature(),
261 CHECK);
262 Handle boot_loader(THREAD, result.get_oop());
263 reset_states(boot_loader(), CHECK);
264 }
265
266 void HeapShared::ensure_determinism(TRAPS) {
267 TempNewSymbol class_name = SymbolTable::new_symbol("jdk/internal/util/WeakReferenceKey");
268 TempNewSymbol method_name = SymbolTable::new_symbol("ensureDeterministicAOTCache");
269
270 Klass* weak_ref_key_class = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
271 precond(weak_ref_key_class != nullptr);
272
273 log_debug(aot)("Calling WeakReferenceKey::ensureDeterministicAOTCache(Object.class)");
274 JavaValue result(T_BOOLEAN);
275 JavaCalls::call_static(&result,
276 weak_ref_key_class,
277 method_name,
278 vmSymbols::void_boolean_signature(),
279 CHECK);
280 assert(result.get_jboolean() == false, "sanity");
281 }
282
283 void HeapShared::prepare_for_archiving(TRAPS) {
284 reset_archived_object_states(CHECK);
285 ensure_determinism(CHECK);
286 }
287
288 HeapShared::ArchivedObjectCache* HeapShared::_archived_object_cache = nullptr;
289
290 // Controls the hashing method for the _archived_object_cache.
291 // Changes from false to true once, after all objects are copied,
292 // inside make_archived_object_cache_gc_safe().
293 // See archived_object_cache_hash() for more details.
294 bool HeapShared::_use_identity_hash_for_archived_object_cache = false;
295
296 bool HeapShared::is_archived_heap_in_use() {
297 if (HeapShared::is_loading()) {
298 if (HeapShared::is_loading_streaming_mode()) {
299 return AOTStreamedHeapLoader::is_in_use();
300 } else {
301 return AOTMappedHeapLoader::is_in_use();
302 }
303 }
304
305 return false;
306 }
307
308 bool HeapShared::can_use_archived_heap() {
309 FileMapInfo* static_mapinfo = FileMapInfo::current_info();
310 if (static_mapinfo == nullptr) {
311 return false;
312 }
313 if (!static_mapinfo->has_heap_region()) {
314 return false;
315 }
316 if (!static_mapinfo->object_streaming_mode() &&
317 !Universe::heap()->can_load_archived_objects() &&
318 !UseG1GC) {
319 // Incompatible object format
320 return false;
321 }
322
323 return true;
324 }
325
326 bool HeapShared::is_too_large_to_archive(size_t size) {
327 if (HeapShared::is_writing_streaming_mode()) {
328 return false;
329 } else {
330 return AOTMappedHeapWriter::is_too_large_to_archive(size);
331 }
332 }
333
334 bool HeapShared::is_too_large_to_archive(oop obj) {
335 if (HeapShared::is_writing_streaming_mode()) {
336 return false;
337 } else {
338 return AOTMappedHeapWriter::is_too_large_to_archive(obj);
339 }
340 }
341
342 bool HeapShared::is_string_too_large_to_archive(oop string) {
343 typeArrayOop value = java_lang_String::value_no_keepalive(string);
344 return is_too_large_to_archive(value);
345 }
346
347 void HeapShared::initialize_loading_mode(HeapArchiveMode mode) {
348 assert(_heap_load_mode == HeapArchiveMode::_uninitialized, "already set?");
349 assert(mode != HeapArchiveMode::_uninitialized, "sanity");
350 _heap_load_mode = mode;
351 };
352
353 void HeapShared::initialize_writing_mode() {
354 assert(!FLAG_IS_ERGO(AOTStreamableObjects), "Should not have been ergonomically set yet");
355
356 if (!CDSConfig::is_dumping_archive()) {
357 // We use FLAG_IS_CMDLINE below because we are specifically looking to warn
358 // a user that explicitly sets the flag on the command line for a JVM that is
359 // not dumping an archive.
360 if (FLAG_IS_CMDLINE(AOTStreamableObjects)) {
361 log_warning(cds)("-XX:%cAOTStreamableObjects was specified, "
362 "AOTStreamableObjects is only used for writing "
363 "the AOT cache.",
364 AOTStreamableObjects ? '+' : '-');
365 }
366 }
367
368 // The below checks use !FLAG_IS_DEFAULT instead of FLAG_IS_CMDLINE
369 // because the one step AOT cache creation transfers the AOTStreamableObjects
370 // flag value from the training JVM to the assembly JVM using an environment
371 // variable that sets the flag as ERGO in the assembly JVM.
372 if (FLAG_IS_DEFAULT(AOTStreamableObjects)) {
373 // By default, the value of AOTStreamableObjects should match !UseCompressedOops.
374 FLAG_SET_DEFAULT(AOTStreamableObjects, !UseCompressedOops);
375 } else if (!AOTStreamableObjects && UseZGC) {
376 // Never write mapped heap with ZGC
377 if (CDSConfig::is_dumping_archive()) {
378 log_warning(cds)("Heap archiving without streaming not supported for -XX:+UseZGC");
379 }
380 FLAG_SET_ERGO(AOTStreamableObjects, true);
381 }
382
383 if (CDSConfig::is_dumping_archive()) {
384 // Select default mode
385 assert(_heap_write_mode == HeapArchiveMode::_uninitialized, "already initialized?");
386 _heap_write_mode = AOTStreamableObjects ? HeapArchiveMode::_streaming : HeapArchiveMode::_mapping;
387 }
388 }
389
390 void HeapShared::initialize_streaming() {
391 assert(is_loading_streaming_mode(), "shouldn't call this");
392 if (can_use_archived_heap()) {
393 AOTStreamedHeapLoader::initialize();
394 }
395 }
396
397 void HeapShared::enable_gc() {
398 if (AOTStreamedHeapLoader::is_in_use()) {
399 AOTStreamedHeapLoader::enable_gc();
400 }
401 }
402
403 void HeapShared::materialize_thread_object() {
404 if (AOTStreamedHeapLoader::is_in_use()) {
405 AOTStreamedHeapLoader::materialize_thread_object();
406 }
407 }
408
409 void HeapShared::archive_interned_string(oop string) {
410 assert(HeapShared::is_writing_mapping_mode(), "Only used by this mode");
411 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, string);
412 assert(success, "shared strings array must not point to arrays or strings that are too large to archive");
413 }
414
415 void HeapShared::finalize_initialization(FileMapInfo* static_mapinfo) {
416 if (HeapShared::is_loading()) {
417 if (HeapShared::is_loading_streaming_mode()) {
418 // Heap initialization can be done only after vtables are initialized by ReadClosure.
419 AOTStreamedHeapLoader::finish_initialization(static_mapinfo);
420 } else {
421 // Finish up archived heap initialization. These must be
422 // done after ReadClosure.
423 AOTMappedHeapLoader::finish_initialization(static_mapinfo);
424 }
425 }
426 }
427
428 void HeapShared::make_archived_object_cache_gc_safe() {
429 ArchivedObjectCache* new_cache = new (mtClass)ArchivedObjectCache(INITIAL_TABLE_SIZE, MAX_TABLE_SIZE);
430
431 // It's safe to change the behavior of the hash function now, because iterate_all()
432 // doesn't call the hash function.
433 // See archived_object_cache_hash() for more details.
434 assert(_use_identity_hash_for_archived_object_cache == false, "happens only once");
435 _use_identity_hash_for_archived_object_cache = true;
436
437 // Copy all CachedOopInfo into a new table using a different hashing algorithm
438 archived_object_cache()->iterate_all([&] (OopHandle oh, CachedOopInfo info) {
439 new_cache->put_when_absent(oh, info);
440 });
441
442 destroy_archived_object_cache();
443 _archived_object_cache = new_cache;
444 }
445
446 HeapShared::CachedOopInfo* HeapShared::get_cached_oop_info(oop obj) {
447 OopHandle oh(Universe::vm_global(), obj);
448 CachedOopInfo* result = _archived_object_cache->get(oh);
449 oh.release(Universe::vm_global());
450 return result;
451 }
452
453 bool HeapShared::has_been_archived(oop obj) {
454 assert(CDSConfig::is_dumping_heap(), "dump-time only");
455 return get_cached_oop_info(obj) != nullptr;
456 }
457
458 int HeapShared::append_root(oop obj) {
459 assert(SafepointSynchronize::is_at_safepoint(), "sanity");
460 assert(CDSConfig::is_dumping_heap(), "dump-time only");
461 assert(_pending_roots != nullptr, "sanity");
462
463 if (obj == nullptr) {
464 assert(_pending_roots->at(0) == nullptr, "root index 0 always maps to null");
465 return 0;
466 } else if (CDSConfig::is_dumping_aot_linked_classes()) {
467 // The AOT compiler may refer the same obj many times, so we
468 // should use the same index for this oop to avoid excessive entries
469 // in the roots array.
470 CachedOopInfo* obj_info = get_cached_oop_info(obj);
471 assert(obj_info != nullptr, "must be archived");
472
473 if (obj_info->root_index() > 0) {
474 return obj_info->root_index();
475 } else {
476 assert(obj_info->root_index() < 0, "must not be zero");
477 int i = _pending_roots->append(obj);
478 obj_info->set_root_index(i);
479 return i;
480 }
481 } else {
482 return _pending_roots->append(obj);
483 }
484 }
485
486 int HeapShared::get_root_index(oop obj) {
487 if (java_lang_Class::is_instance(obj)) {
488 obj = scratch_java_mirror(obj);
489 }
490
491 CachedOopInfo* obj_info = get_cached_oop_info(obj);
492 const char* error = nullptr;
493 if (obj_info == nullptr) {
494 error = "Not a cached oop";
495 } else if (obj_info->root_index() < 0) {
496 error = "Not a cached oop root";
497 } else {
498 return obj_info->root_index();
499 }
500
501 ResourceMark rm;
502 log_debug(aot, codecache, oops)("%s: " INTPTR_FORMAT " (%s)", error,
503 cast_from_oop<uintptr_t>(obj),
504 obj->klass()->external_name());
505 return -1;
506 }
507
508 oop HeapShared::get_root(int index, bool clear) {
509 assert(index >= 0, "sanity");
510 assert(is_archived_heap_in_use(), "getting roots into heap that is not used");
511
512 oop result;
513 if (HeapShared::is_loading_streaming_mode()) {
514 result = AOTStreamedHeapLoader::get_root(index);
515 } else {
516 assert(HeapShared::is_loading_mapping_mode(), "must be");
517 result = AOTMappedHeapLoader::get_root(index);
518 }
519
520 if (clear) {
521 clear_root(index);
522 }
523
524 return result;
525 }
526
527 void HeapShared::finish_materialize_objects() {
528 if (AOTStreamedHeapLoader::is_in_use()) {
529 AOTStreamedHeapLoader::finish_materialize_objects();
530 }
531 }
532
533 void HeapShared::clear_root(int index) {
534 if (CDSConfig::is_using_aot_linked_classes()) {
535 // When AOT linked classes are in use, all roots will be in use all
536 // the time, there's no benefit for clearing the roots. Also, we
537 // can't clear the roots as they can be shared.
538 return;
539 }
540
541 assert(index >= 0, "sanity");
542 assert(CDSConfig::is_using_archive(), "must be");
543 if (is_archived_heap_in_use()) {
544 if (log_is_enabled(Debug, aot, heap)) {
545 log_debug(aot, heap)("Clearing root %d: was %zu", index, p2i(get_root(index, false /* clear */)));
546 }
547 if (HeapShared::is_loading_streaming_mode()) {
548 AOTStreamedHeapLoader::clear_root(index);
549 } else {
550 assert(HeapShared::is_loading_mapping_mode(), "must be");
551 AOTMappedHeapLoader::clear_root(index);
552 }
553 }
554 }
555
556 bool HeapShared::archive_object(oop obj, oop referrer, KlassSubGraphInfo* subgraph_info) {
557 assert(CDSConfig::is_dumping_heap(), "dump-time only");
558
559 assert(!obj->is_stackChunk(), "do not archive stack chunks");
560 if (has_been_archived(obj)) {
561 return true;
562 }
563
564 if (is_too_large_to_archive(obj)) {
565 log_debug(aot, heap)("Cannot archive, object (" PTR_FORMAT ") is too large: %zu",
566 p2i(obj), obj->size());
567 debug_trace();
568 return false;
569 }
570
571 AOTOopChecker::check(obj); // Make sure contents of this oop are safe.
572 count_allocation(obj->size());
573
574 if (HeapShared::is_writing_streaming_mode()) {
575 AOTStreamedHeapWriter::add_source_obj(obj);
576 } else {
577 AOTMappedHeapWriter::add_source_obj(obj);
578 }
579
580 OopHandle oh(Universe::vm_global(), obj);
581 CachedOopInfo info = make_cached_oop_info(obj, referrer);
582 archived_object_cache()->put_when_absent(oh, info);
583 archived_object_cache()->maybe_grow();
584
585 Klass* k = obj->klass();
586 if (k->is_instance_klass()) {
587 // Whenever we see a non-array Java object of type X, we mark X to be aot-initialized.
588 // This ensures that during the production run, whenever Java code sees a cached object
589 // of type X, we know that X is already initialized. (see TODO comment below ...)
590
591 if (InstanceKlass::cast(k)->is_enum_subclass()
592 // We can't rerun <clinit> of enum classes (see cdsEnumKlass.cpp) so
593 // we must store them as AOT-initialized.
594 || (subgraph_info == _dump_time_special_subgraph))
595 // TODO: we do this only for the special subgraph for now. Extending this to
596 // other subgraphs would require more refactoring of the core library (such as
597 // move some initialization logic into runtimeSetup()).
598 //
599 // For the other subgraphs, we have a weaker mechanism to ensure that
600 // all classes in a subgraph are initialized before the subgraph is programmatically
601 // returned from jdk.internal.misc.CDS::initializeFromArchive().
602 // See HeapShared::initialize_from_archived_subgraph().
603 {
604 AOTArtifactFinder::add_aot_inited_class(InstanceKlass::cast(k));
605 }
606
607 if (java_lang_Class::is_instance(obj)) {
608 Klass* mirror_k = java_lang_Class::as_Klass(obj);
609 if (mirror_k != nullptr) {
610 AOTArtifactFinder::add_cached_class(mirror_k);
611 }
612 } else if (java_lang_invoke_ResolvedMethodName::is_instance(obj)) {
613 Method* m = java_lang_invoke_ResolvedMethodName::vmtarget(obj);
614 if (m != nullptr) {
615 if (RegeneratedClasses::has_been_regenerated(m)) {
616 m = RegeneratedClasses::get_regenerated_object(m);
617 }
618 InstanceKlass* method_holder = m->method_holder();
619 AOTArtifactFinder::add_cached_class(method_holder);
620 }
621 }
622 }
623
624 if (log_is_enabled(Debug, aot, heap)) {
625 ResourceMark rm;
626 LogTarget(Debug, aot, heap) log;
627 LogStream out(log);
628 out.print("Archived heap object " PTR_FORMAT " : %s ",
629 p2i(obj), obj->klass()->external_name());
630 if (java_lang_Class::is_instance(obj)) {
631 Klass* k = java_lang_Class::as_Klass(obj);
632 if (k != nullptr) {
633 out.print("%s", k->external_name());
634 } else {
635 out.print("primitive");
636 }
637 }
638 out.cr();
639 }
640
641 return true;
642 }
643
644 class MetaspaceObjToOopHandleTable: public HashTable<MetaspaceObj*, OopHandle,
645 36137, // prime number
646 AnyObj::C_HEAP,
647 mtClassShared> {
648 public:
649 oop get_oop(MetaspaceObj* ptr) {
650 MutexLocker ml(ScratchObjects_lock, Mutex::_no_safepoint_check_flag);
651 OopHandle* handle = get(ptr);
652 if (handle != nullptr) {
653 return handle->resolve();
654 } else {
655 return nullptr;
656 }
657 }
658 void set_oop(MetaspaceObj* ptr, oop o) {
659 MutexLocker ml(ScratchObjects_lock, Mutex::_no_safepoint_check_flag);
660 OopHandle handle(Universe::vm_global(), o);
661 put_when_absent(ptr, handle);
662 }
663 void remove_oop(MetaspaceObj* ptr) {
664 MutexLocker ml(ScratchObjects_lock, Mutex::_no_safepoint_check_flag);
665 OopHandle* handle = get(ptr);
666 if (handle != nullptr) {
667 handle->release(Universe::vm_global());
668 remove(ptr);
669 }
670 }
671 };
672
673 void HeapShared::add_scratch_resolved_references(ConstantPool* src, objArrayOop dest) {
674 if (CDSConfig::is_dumping_preimage_static_archive() && scratch_resolved_references(src) != nullptr) {
675 // We are in AOT training run. The class has been redefined and we are giving it a new resolved_reference.
676 // Ignore it, as this class will be excluded from the AOT config.
677 return;
678 }
679 if (SystemDictionaryShared::is_builtin_loader(src->pool_holder()->class_loader_data())) {
680 _scratch_objects_table->set_oop(src, dest);
681 }
682 }
683
684 objArrayOop HeapShared::scratch_resolved_references(ConstantPool* src) {
685 return (objArrayOop)_scratch_objects_table->get_oop(src);
686 }
687
688 void HeapShared::init_dumping() {
689 _scratch_objects_table = new (mtClass)MetaspaceObjToOopHandleTable();
690 _pending_roots = new GrowableArrayCHeap<oop, mtClassShared>(500);
691 _pending_roots->append(nullptr); // root index 0 represents a null oop
692 }
693
694 void HeapShared::init_scratch_objects_for_basic_type_mirrors(TRAPS) {
695 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
696 BasicType bt = (BasicType)i;
697 if (!is_reference_type(bt)) {
698 oop m = java_lang_Class::create_basic_type_mirror(type2name(bt), bt, CHECK);
699 _scratch_basic_type_mirrors[i] = OopHandle(Universe::vm_global(), m);
700 }
701 }
702 }
703
704 // Given java_mirror that represents a (primitive or reference) type T,
705 // return the "scratch" version that represents the same type T. Note
706 // that java_mirror will be returned if the mirror is already a scratch mirror.
707 //
708 // See java_lang_Class::create_scratch_mirror() for more info.
709 oop HeapShared::scratch_java_mirror(oop java_mirror) {
710 assert(java_lang_Class::is_instance(java_mirror), "must be");
711
712 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
713 BasicType bt = (BasicType)i;
714 if (!is_reference_type(bt)) {
715 if (_scratch_basic_type_mirrors[i].resolve() == java_mirror) {
716 return java_mirror;
717 }
718 }
719 }
720
721 if (java_lang_Class::is_primitive(java_mirror)) {
722 return scratch_java_mirror(java_lang_Class::as_BasicType(java_mirror));
723 } else {
724 return scratch_java_mirror(java_lang_Class::as_Klass(java_mirror));
725 }
726 }
727
728 oop HeapShared::scratch_java_mirror(BasicType t) {
729 assert((uint)t < T_VOID+1, "range check");
730 assert(!is_reference_type(t), "sanity");
731 return _scratch_basic_type_mirrors[t].resolve();
732 }
733
734 oop HeapShared::scratch_java_mirror(Klass* k) {
735 return _scratch_objects_table->get_oop(k);
736 }
737
738 void HeapShared::set_scratch_java_mirror(Klass* k, oop mirror) {
739 _scratch_objects_table->set_oop(k, mirror);
740 }
741
742 void HeapShared::remove_scratch_objects(Klass* k) {
743 // Klass is being deallocated. Java mirror can still be alive, and it should not
744 // point to dead klass. We need to break the link from mirror to the Klass.
745 // See how InstanceKlass::deallocate_contents does it for normal mirrors.
746 oop mirror = _scratch_objects_table->get_oop(k);
747 if (mirror != nullptr) {
748 java_lang_Class::set_klass(mirror, nullptr);
749 }
750 _scratch_objects_table->remove_oop(k);
751 if (k->is_instance_klass()) {
752 _scratch_objects_table->remove(InstanceKlass::cast(k)->constants());
753 }
754 }
755
756 //TODO: we eventually want a more direct test for these kinds of things.
757 //For example the JVM could record some bit of context from the creation
758 //of the klass, such as who called the hidden class factory. Using
759 //string compares on names is fragile and will break as soon as somebody
760 //changes the names in the JDK code. See discussion in JDK-8342481 for
761 //related ideas about marking AOT-related classes.
762 bool HeapShared::is_lambda_form_klass(InstanceKlass* ik) {
763 return ik->is_hidden() &&
764 (ik->name()->starts_with("java/lang/invoke/LambdaForm$MH+") ||
765 ik->name()->starts_with("java/lang/invoke/LambdaForm$DMH+") ||
766 ik->name()->starts_with("java/lang/invoke/LambdaForm$BMH+") ||
767 ik->name()->starts_with("java/lang/invoke/LambdaForm$VH+"));
768 }
769
770 bool HeapShared::is_lambda_proxy_klass(InstanceKlass* ik) {
771 return ik->is_hidden() && (ik->name()->index_of_at(0, "$$Lambda+", 9) > 0);
772 }
773
774 bool HeapShared::is_string_concat_klass(InstanceKlass* ik) {
775 return ik->is_hidden() && ik->name()->starts_with("java/lang/String$$StringConcat");
776 }
777
778 bool HeapShared::is_archivable_hidden_klass(InstanceKlass* ik) {
779 return CDSConfig::is_dumping_method_handles() &&
780 (is_lambda_form_klass(ik) || is_lambda_proxy_klass(ik) || is_string_concat_klass(ik));
781 }
782
783
784 void HeapShared::copy_and_rescan_aot_inited_mirror(InstanceKlass* ik) {
785 ik->set_has_aot_initialized_mirror();
786
787 oop orig_mirror;
788 if (RegeneratedClasses::is_regenerated_object(ik)) {
789 InstanceKlass* orig_ik = RegeneratedClasses::get_original_object(ik);
790 precond(orig_ik->is_initialized());
791 orig_mirror = orig_ik->java_mirror();
792 } else {
793 precond(ik->is_initialized());
794 orig_mirror = ik->java_mirror();
795 }
796
797 oop m = scratch_java_mirror(ik);
798 int nfields = 0;
799 for (JavaFieldStream fs(ik); !fs.done(); fs.next()) {
800 if (fs.access_flags().is_static()) {
801 fieldDescriptor& fd = fs.field_descriptor();
802 int offset = fd.offset();
803 switch (fd.field_type()) {
804 case T_OBJECT:
805 case T_ARRAY:
806 {
807 oop field_obj = orig_mirror->obj_field(offset);
808 if (offset == java_lang_Class::reflection_data_offset()) {
809 // Class::reflectData use SoftReference, which cannot be archived. Set it
810 // to null and it will be recreated at runtime.
811 field_obj = nullptr;
812 }
813 m->obj_field_put(offset, field_obj);
814 if (field_obj != nullptr) {
815 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, field_obj);
816 assert(success, "sanity");
817 }
818 }
819 break;
820 case T_BOOLEAN:
821 m->bool_field_put(offset, orig_mirror->bool_field(offset));
822 break;
823 case T_BYTE:
824 m->byte_field_put(offset, orig_mirror->byte_field(offset));
825 break;
826 case T_SHORT:
827 m->short_field_put(offset, orig_mirror->short_field(offset));
828 break;
829 case T_CHAR:
830 m->char_field_put(offset, orig_mirror->char_field(offset));
831 break;
832 case T_INT:
833 m->int_field_put(offset, orig_mirror->int_field(offset));
834 break;
835 case T_LONG:
836 m->long_field_put(offset, orig_mirror->long_field(offset));
837 break;
838 case T_FLOAT:
839 m->float_field_put(offset, orig_mirror->float_field(offset));
840 break;
841 case T_DOUBLE:
842 m->double_field_put(offset, orig_mirror->double_field(offset));
843 break;
844 default:
845 ShouldNotReachHere();
846 }
847 nfields ++;
848 }
849 }
850
851 oop class_data = java_lang_Class::class_data(orig_mirror);
852 java_lang_Class::set_class_data(m, class_data);
853 if (class_data != nullptr) {
854 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, class_data);
855 assert(success, "sanity");
856 }
857
858 if (log_is_enabled(Debug, aot, init)) {
859 ResourceMark rm;
860 log_debug(aot, init)("copied %3d field(s) in aot-initialized mirror %s%s%s", nfields, ik->external_name(),
861 ik->is_hidden() ? " (hidden)" : "",
862 ik->is_enum_subclass() ? " (enum)" : "");
863 }
864 }
865
866 void HeapShared::copy_java_mirror(oop orig_mirror, oop scratch_m) {
867 // We need to retain the identity_hash, because it may have been used by some hashtables
868 // in the shared heap.
869 if (!orig_mirror->fast_no_hash_check()) {
870 intptr_t src_hash = orig_mirror->identity_hash();
871 if (UseCompactObjectHeaders) {
872 narrowKlass nk = CompressedKlassPointers::encode(orig_mirror->klass());
873 scratch_m->set_mark(markWord::prototype().set_narrow_klass(nk).copy_set_hash(src_hash));
874 } else {
875 scratch_m->set_mark(markWord::prototype().copy_set_hash(src_hash));
876 }
877 assert(scratch_m->mark().is_unlocked(), "sanity");
878
879 DEBUG_ONLY(intptr_t archived_hash = scratch_m->identity_hash());
880 assert(src_hash == archived_hash, "Different hash codes: original " INTPTR_FORMAT ", archived " INTPTR_FORMAT, src_hash, archived_hash);
881 }
882
883 if (CDSConfig::is_dumping_aot_linked_classes()) {
884 java_lang_Class::set_module(scratch_m, java_lang_Class::module(orig_mirror));
885 java_lang_Class::set_protection_domain(scratch_m, java_lang_Class::protection_domain(orig_mirror));
886 }
887 }
888
889 static objArrayOop get_archived_resolved_references(InstanceKlass* src_ik) {
890 if (SystemDictionaryShared::is_builtin_loader(src_ik->class_loader_data())) {
891 objArrayOop rr = src_ik->constants()->resolved_references_or_null();
892 if (rr != nullptr && !HeapShared::is_too_large_to_archive(rr)) {
893 return HeapShared::scratch_resolved_references(src_ik->constants());
894 }
895 }
896 return nullptr;
897 }
898
899 int HeapShared::archive_exception_instance(oop exception) {
900 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, exception);
901 assert(success, "sanity");
902 return append_root(exception);
903 }
904
905 void HeapShared::get_pointer_info(oop src_obj, bool& has_oop_pointers, bool& has_native_pointers) {
906 OopHandle oh(&src_obj);
907 CachedOopInfo* info = archived_object_cache()->get(oh);
908 assert(info != nullptr, "must be");
909 has_oop_pointers = info->has_oop_pointers();
910 has_native_pointers = info->has_native_pointers();
911 }
912
913 void HeapShared::set_has_native_pointers(oop src_obj) {
914 OopHandle oh(&src_obj);
915 CachedOopInfo* info = archived_object_cache()->get(oh);
916 assert(info != nullptr, "must be");
917 info->set_has_native_pointers();
918 }
919
920 // Between start_scanning_for_oops() and end_scanning_for_oops(), we discover all Java heap objects that
921 // should be stored in the AOT cache. The scanning is coordinated by AOTArtifactFinder.
922 void HeapShared::start_scanning_for_oops() {
923 {
924 NoSafepointVerifier nsv;
925
926 // The special subgraph doesn't belong to any class. We use Object_klass() here just
927 // for convenience.
928 _dump_time_special_subgraph = init_subgraph_info(vmClasses::Object_klass(), false);
929
930 // Cache for recording where the archived objects are copied to
931 create_archived_object_cache();
932
933 if (HeapShared::is_writing_mapping_mode() && (UseG1GC || UseCompressedOops)) {
934 aot_log_info(aot)("Heap range = [" PTR_FORMAT " - " PTR_FORMAT "]",
935 UseCompressedOops ? p2i(CompressedOops::begin()) :
936 p2i((address)G1CollectedHeap::heap()->reserved().start()),
937 UseCompressedOops ? p2i(CompressedOops::end()) :
938 p2i((address)G1CollectedHeap::heap()->reserved().end()));
939 }
940
941 archive_subgraphs();
942 }
943
944 init_seen_objects_table();
945 Universe::archive_exception_instances();
946 }
947
948 void HeapShared::end_scanning_for_oops() {
949 if (is_writing_mapping_mode()) {
950 StringTable::init_shared_table();
951 }
952 delete_seen_objects_table();
953 }
954
955 void HeapShared::write_heap(AOTMappedHeapInfo* mapped_heap_info, AOTStreamedHeapInfo* streamed_heap_info) {
956 {
957 NoSafepointVerifier nsv;
958 CDSHeapVerifier::verify();
959 check_special_subgraph_classes();
960 }
961
962 if (HeapShared::is_writing_mapping_mode()) {
963 StringTable::write_shared_table();
964 AOTMappedHeapWriter::write(_pending_roots, mapped_heap_info);
965 } else {
966 assert(HeapShared::is_writing_streaming_mode(), "are there more modes?");
967 AOTStreamedHeapWriter::write(_pending_roots, streamed_heap_info);
968 }
969
970 ArchiveBuilder::OtherROAllocMark mark;
971 write_subgraph_info_table();
972
973 delete _pending_roots;
974 _pending_roots = nullptr;
975
976 make_archived_object_cache_gc_safe();
977 }
978
979 void HeapShared::scan_java_mirror(oop orig_mirror) {
980 oop m = scratch_java_mirror(orig_mirror);
981 if (m != nullptr) { // nullptr if for custom class loader
982 copy_java_mirror(orig_mirror, m);
983 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, m);
984 assert(success, "sanity");
985 }
986 }
987
988 void HeapShared::scan_java_class(Klass* orig_k) {
989 scan_java_mirror(orig_k->java_mirror());
990
991 if (orig_k->is_instance_klass()) {
992 InstanceKlass* orig_ik = InstanceKlass::cast(orig_k);
993 orig_ik->constants()->prepare_resolved_references_for_archiving();
994 objArrayOop rr = get_archived_resolved_references(orig_ik);
995 if (rr != nullptr) {
996 bool success = HeapShared::archive_reachable_objects_from(1, _dump_time_special_subgraph, rr);
997 assert(success, "must be");
998 }
999 }
1000 }
1001
1002 void HeapShared::archive_subgraphs() {
1003 assert(CDSConfig::is_dumping_heap(), "must be");
1004
1005 if (CDSConfig::is_dumping_klass_subgraphs()) {
1006 archive_object_subgraphs(archive_subgraph_entry_fields,
1007 false /* is_full_module_graph */);
1008 if (CDSConfig::is_dumping_full_module_graph()) {
1009 archive_object_subgraphs(fmg_archive_subgraph_entry_fields,
1010 true /* is_full_module_graph */);
1011 }
1012 }
1013 }
1014
1015 //
1016 // Subgraph archiving support
1017 //
1018 HeapShared::DumpTimeKlassSubGraphInfoTable* HeapShared::_dump_time_subgraph_info_table = nullptr;
1019 HeapShared::RunTimeKlassSubGraphInfoTable HeapShared::_run_time_subgraph_info_table;
1020
1021 // Get the subgraph_info for Klass k. A new subgraph_info is created if
1022 // there is no existing one for k. The subgraph_info records the "buffered"
1023 // address of the class.
1024 KlassSubGraphInfo* HeapShared::init_subgraph_info(Klass* k, bool is_full_module_graph) {
1025 assert(CDSConfig::is_dumping_heap(), "dump time only");
1026 bool created;
1027 KlassSubGraphInfo* info =
1028 _dump_time_subgraph_info_table->put_if_absent(k, KlassSubGraphInfo(k, is_full_module_graph),
1029 &created);
1030 assert(created, "must not initialize twice");
1031 return info;
1032 }
1033
1034 KlassSubGraphInfo* HeapShared::get_subgraph_info(Klass* k) {
1035 assert(CDSConfig::is_dumping_heap(), "dump time only");
1036 KlassSubGraphInfo* info = _dump_time_subgraph_info_table->get(k);
1037 assert(info != nullptr, "must have been initialized");
1038 return info;
1039 }
1040
1041 // Add an entry field to the current KlassSubGraphInfo.
1042 void KlassSubGraphInfo::add_subgraph_entry_field(int static_field_offset, oop v) {
1043 assert(CDSConfig::is_dumping_heap(), "dump time only");
1044 if (_subgraph_entry_fields == nullptr) {
1045 _subgraph_entry_fields =
1046 new (mtClass) GrowableArray<int>(10, mtClass);
1047 }
1048 _subgraph_entry_fields->append(static_field_offset);
1049 _subgraph_entry_fields->append(HeapShared::append_root(v));
1050 }
1051
1052 // Add the Klass* for an object in the current KlassSubGraphInfo's subgraphs.
1053 // Only objects of boot classes can be included in sub-graph.
1054 void KlassSubGraphInfo::add_subgraph_object_klass(Klass* orig_k) {
1055 assert(CDSConfig::is_dumping_heap(), "dump time only");
1056
1057 if (_subgraph_object_klasses == nullptr) {
1058 _subgraph_object_klasses =
1059 new (mtClass) GrowableArray<Klass*>(50, mtClass);
1060 }
1061
1062 if (_k == orig_k) {
1063 // Don't add the Klass containing the sub-graph to it's own klass
1064 // initialization list.
1065 return;
1066 }
1067
1068 if (orig_k->is_instance_klass()) {
1069 #ifdef ASSERT
1070 InstanceKlass* ik = InstanceKlass::cast(orig_k);
1071 if (CDSConfig::is_dumping_method_handles()) {
1072 // -XX:AOTInitTestClass must be used carefully in regression tests to
1073 // include only classes that are safe to aot-initialize.
1074 assert(ik->class_loader() == nullptr ||
1075 HeapShared::is_lambda_proxy_klass(ik) ||
1076 AOTClassInitializer::has_test_class(),
1077 "we can archive only instances of boot classes or lambda proxy classes");
1078 } else {
1079 assert(ik->class_loader() == nullptr, "must be boot class");
1080 }
1081 #endif
1082 // vmClasses::xxx_klass() are not updated, need to check
1083 // the original Klass*
1084 if (orig_k == vmClasses::String_klass() ||
1085 orig_k == vmClasses::Object_klass()) {
1086 // Initialized early during VM initialization. No need to be added
1087 // to the sub-graph object class list.
1088 return;
1089 }
1090 check_allowed_klass(InstanceKlass::cast(orig_k));
1091 } else if (orig_k->is_objArray_klass()) {
1092 Klass* abk = ObjArrayKlass::cast(orig_k)->bottom_klass();
1093 if (abk->is_instance_klass()) {
1094 assert(InstanceKlass::cast(abk)->defined_by_boot_loader(),
1095 "must be boot class");
1096 check_allowed_klass(InstanceKlass::cast(ObjArrayKlass::cast(orig_k)->bottom_klass()));
1097 }
1098 if (orig_k == Universe::objectArrayKlass()) {
1099 // Initialized early during Universe::genesis. No need to be added
1100 // to the list.
1101 return;
1102 }
1103 } else {
1104 assert(orig_k->is_typeArray_klass(), "must be");
1105 // Primitive type arrays are created early during Universe::genesis.
1106 return;
1107 }
1108
1109 if (log_is_enabled(Debug, aot, heap)) {
1110 if (!_subgraph_object_klasses->contains(orig_k)) {
1111 ResourceMark rm;
1112 log_debug(aot, heap)("Adding klass %s", orig_k->external_name());
1113 }
1114 }
1115
1116 _subgraph_object_klasses->append_if_missing(orig_k);
1117 _has_non_early_klasses |= is_non_early_klass(orig_k);
1118 }
1119
1120 void KlassSubGraphInfo::check_allowed_klass(InstanceKlass* ik) {
1121 #ifndef PRODUCT
1122 if (AOTClassInitializer::has_test_class()) {
1123 // The tests can cache arbitrary types of objects.
1124 return;
1125 }
1126 #endif
1127
1128 if (ik->module()->name() == vmSymbols::java_base()) {
1129 assert(ik->package() != nullptr, "classes in java.base cannot be in unnamed package");
1130 return;
1131 }
1132
1133 const char* lambda_msg = "";
1134 if (CDSConfig::is_dumping_method_handles()) {
1135 lambda_msg = ", or a lambda proxy class";
1136 if (HeapShared::is_lambda_proxy_klass(ik) &&
1137 (ik->class_loader() == nullptr ||
1138 ik->class_loader() == SystemDictionary::java_platform_loader() ||
1139 ik->class_loader() == SystemDictionary::java_system_loader())) {
1140 return;
1141 }
1142 }
1143
1144 #ifndef PRODUCT
1145 if (!ik->module()->is_named() && ik->package() == nullptr && ArchiveHeapTestClass != nullptr) {
1146 // This class is loaded by ArchiveHeapTestClass
1147 return;
1148 }
1149 const char* testcls_msg = ", or a test class in an unnamed package of an unnamed module";
1150 #else
1151 const char* testcls_msg = "";
1152 #endif
1153
1154 ResourceMark rm;
1155 log_error(aot, heap)("Class %s not allowed in archive heap. Must be in java.base%s%s",
1156 ik->external_name(), lambda_msg, testcls_msg);
1157 AOTMetaspace::unrecoverable_writing_error();
1158 }
1159
1160 bool KlassSubGraphInfo::is_non_early_klass(Klass* k) {
1161 if (k->is_objArray_klass()) {
1162 k = ObjArrayKlass::cast(k)->bottom_klass();
1163 }
1164 if (k->is_instance_klass()) {
1165 if (!SystemDictionaryShared::is_early_klass(InstanceKlass::cast(k))) {
1166 ResourceMark rm;
1167 log_info(aot, heap)("non-early: %s", k->external_name());
1168 return true;
1169 } else {
1170 return false;
1171 }
1172 } else {
1173 return false;
1174 }
1175 }
1176
1177 // Initialize an archived subgraph_info_record from the given KlassSubGraphInfo.
1178 void ArchivedKlassSubGraphInfoRecord::init(KlassSubGraphInfo* info) {
1179 _k = ArchiveBuilder::get_buffered_klass(info->klass());
1180 _entry_field_records = nullptr;
1181 _subgraph_object_klasses = nullptr;
1182 _is_full_module_graph = info->is_full_module_graph();
1183
1184 if (_is_full_module_graph) {
1185 // Consider all classes referenced by the full module graph as early -- we will be
1186 // allocating objects of these classes during JVMTI early phase, so they cannot
1187 // be processed by (non-early) JVMTI ClassFileLoadHook
1188 _has_non_early_klasses = false;
1189 } else {
1190 _has_non_early_klasses = info->has_non_early_klasses();
1191 }
1192
1193 if (_has_non_early_klasses) {
1194 ResourceMark rm;
1195 log_info(aot, heap)(
1196 "Subgraph of klass %s has non-early klasses and cannot be used when JVMTI ClassFileLoadHook is enabled",
1197 _k->external_name());
1198 }
1199
1200 // populate the entry fields
1201 GrowableArray<int>* entry_fields = info->subgraph_entry_fields();
1202 if (entry_fields != nullptr) {
1203 int num_entry_fields = entry_fields->length();
1204 assert(num_entry_fields % 2 == 0, "sanity");
1205 _entry_field_records =
1206 ArchiveBuilder::new_ro_array<int>(num_entry_fields);
1207 for (int i = 0 ; i < num_entry_fields; i++) {
1208 _entry_field_records->at_put(i, entry_fields->at(i));
1209 }
1210 }
1211
1212 // <recorded_klasses> has the Klasses of all the objects that are referenced by this subgraph.
1213 // Copy those that need to be explicitly initialized into <_subgraph_object_klasses>.
1214 GrowableArray<Klass*>* recorded_klasses = info->subgraph_object_klasses();
1215 if (recorded_klasses != nullptr) {
1216 // AOT-inited classes are automatically marked as "initialized" during bootstrap. When
1217 // programmatically loading a subgraph, we only need to explicitly initialize the classes
1218 // that are not aot-inited.
1219 int num_to_copy = 0;
1220 for (int i = 0; i < recorded_klasses->length(); i++) {
1221 Klass* subgraph_k = ArchiveBuilder::get_buffered_klass(recorded_klasses->at(i));
1222 if (!subgraph_k->has_aot_initialized_mirror()) {
1223 num_to_copy ++;
1224 }
1225 }
1226
1227 _subgraph_object_klasses = ArchiveBuilder::new_ro_array<Klass*>(num_to_copy);
1228 bool is_special = (_k == ArchiveBuilder::get_buffered_klass(vmClasses::Object_klass()));
1229 for (int i = 0, n = 0; i < recorded_klasses->length(); i++) {
1230 Klass* subgraph_k = ArchiveBuilder::get_buffered_klass(recorded_klasses->at(i));
1231 if (subgraph_k->has_aot_initialized_mirror()) {
1232 continue;
1233 }
1234 if (log_is_enabled(Info, aot, heap)) {
1235 ResourceMark rm;
1236 const char* owner_name = is_special ? "<special>" : _k->external_name();
1237 if (subgraph_k->is_instance_klass()) {
1238 InstanceKlass* src_ik = InstanceKlass::cast(ArchiveBuilder::current()->get_source_addr(subgraph_k));
1239 }
1240 log_info(aot, heap)(
1241 "Archived object klass %s (%2d) => %s",
1242 owner_name, n, subgraph_k->external_name());
1243 }
1244 _subgraph_object_klasses->at_put(n, subgraph_k);
1245 ArchivePtrMarker::mark_pointer(_subgraph_object_klasses->adr_at(n));
1246 n++;
1247 }
1248 }
1249
1250 ArchivePtrMarker::mark_pointer(&_k);
1251 ArchivePtrMarker::mark_pointer(&_entry_field_records);
1252 ArchivePtrMarker::mark_pointer(&_subgraph_object_klasses);
1253 }
1254
1255 class HeapShared::CopyKlassSubGraphInfoToArchive : StackObj {
1256 CompactHashtableWriter* _writer;
1257 public:
1258 CopyKlassSubGraphInfoToArchive(CompactHashtableWriter* writer) : _writer(writer) {}
1259
1260 bool do_entry(Klass* klass, KlassSubGraphInfo& info) {
1261 if (info.subgraph_object_klasses() != nullptr || info.subgraph_entry_fields() != nullptr) {
1262 ArchivedKlassSubGraphInfoRecord* record = HeapShared::archive_subgraph_info(&info);
1263 Klass* buffered_k = ArchiveBuilder::get_buffered_klass(klass);
1264 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary((address)buffered_k);
1265 _writer->add(hash, AOTCompressedPointers::encode_not_null(record));
1266 }
1267 return true; // keep on iterating
1268 }
1269 };
1270
1271 ArchivedKlassSubGraphInfoRecord* HeapShared::archive_subgraph_info(KlassSubGraphInfo* info) {
1272 ArchivedKlassSubGraphInfoRecord* record =
1273 (ArchivedKlassSubGraphInfoRecord*)ArchiveBuilder::ro_region_alloc(sizeof(ArchivedKlassSubGraphInfoRecord));
1274 record->init(info);
1275 if (info == _dump_time_special_subgraph) {
1276 _run_time_special_subgraph = record;
1277 }
1278 return record;
1279 }
1280
1281 // Build the records of archived subgraph infos, which include:
1282 // - Entry points to all subgraphs from the containing class mirror. The entry
1283 // points are static fields in the mirror. For each entry point, the field
1284 // offset, and value are recorded in the sub-graph
1285 // info. The value is stored back to the corresponding field at runtime.
1286 // - A list of klasses that need to be loaded/initialized before archived
1287 // java object sub-graph can be accessed at runtime.
1288 void HeapShared::write_subgraph_info_table() {
1289 // Allocate the contents of the hashtable(s) inside the RO region of the CDS archive.
1290 DumpTimeKlassSubGraphInfoTable* d_table = _dump_time_subgraph_info_table;
1291 CompactHashtableStats stats;
1292
1293 _run_time_subgraph_info_table.reset();
1294
1295 CompactHashtableWriter writer(d_table->number_of_entries(), &stats);
1296 CopyKlassSubGraphInfoToArchive copy(&writer);
1297 d_table->iterate(©);
1298 writer.dump(&_run_time_subgraph_info_table, "subgraphs");
1299
1300 #ifndef PRODUCT
1301 if (ArchiveHeapTestClass != nullptr) {
1302 size_t len = strlen(ArchiveHeapTestClass) + 1;
1303 Array<char>* array = ArchiveBuilder::new_ro_array<char>((int)len);
1304 strncpy(array->adr_at(0), ArchiveHeapTestClass, len);
1305 _archived_ArchiveHeapTestClass = array;
1306 }
1307 #endif
1308 if (log_is_enabled(Info, aot, heap)) {
1309 print_stats();
1310 }
1311 }
1312
1313 void HeapShared::serialize_tables(SerializeClosure* soc) {
1314
1315 #ifndef PRODUCT
1316 soc->do_ptr(&_archived_ArchiveHeapTestClass);
1317 if (soc->reading() && _archived_ArchiveHeapTestClass != nullptr) {
1318 _test_class_name = _archived_ArchiveHeapTestClass->adr_at(0);
1319 setup_test_class(_test_class_name);
1320 }
1321 #endif
1322
1323 _run_time_subgraph_info_table.serialize_header(soc);
1324 soc->do_ptr(&_run_time_special_subgraph);
1325 }
1326
1327 static void verify_the_heap(Klass* k, const char* which) {
1328 if (VerifyArchivedFields > 0) {
1329 ResourceMark rm;
1330 log_info(aot, heap)("Verify heap %s initializing static field(s) in %s",
1331 which, k->external_name());
1332
1333 if (VerifyArchivedFields == 1) {
1334 VM_Verify verify_op;
1335 VMThread::execute(&verify_op);
1336 } else if (VerifyArchivedFields == 2 && is_init_completed()) {
1337 // At this time, the oop->klass() of some archived objects in the heap may not
1338 // have been loaded into the system dictionary yet. Nevertheless, oop->klass() should
1339 // have enough information (object size, oop maps, etc) so that a GC can be safely
1340 // performed.
1341 //
1342 // -XX:VerifyArchivedFields=2 force a GC to happen in such an early stage
1343 // to check for GC safety.
1344 log_info(aot, heap)("Trigger GC %s initializing static field(s) in %s",
1345 which, k->external_name());
1346 FlagSetting fs1(VerifyBeforeGC, true);
1347 FlagSetting fs2(VerifyDuringGC, true);
1348 FlagSetting fs3(VerifyAfterGC, true);
1349 Universe::heap()->collect(GCCause::_java_lang_system_gc);
1350 }
1351 }
1352 }
1353
1354 // Before GC can execute, we must ensure that all oops reachable from HeapShared::roots()
1355 // have a valid klass. I.e., oopDesc::klass() must have already been resolved.
1356 //
1357 // Note: if a ArchivedKlassSubGraphInfoRecord contains non-early classes, and JVMTI
1358 // ClassFileLoadHook is enabled, it's possible for this class to be dynamically replaced. In
1359 // this case, we will not load the ArchivedKlassSubGraphInfoRecord and will clear its roots.
1360 void HeapShared::resolve_classes(JavaThread* current) {
1361 assert(CDSConfig::is_using_archive(), "runtime only!");
1362 if (CDSConfig::is_using_klass_subgraphs()) {
1363 resolve_classes_for_subgraphs(current, archive_subgraph_entry_fields);
1364 resolve_classes_for_subgraphs(current, fmg_archive_subgraph_entry_fields);
1365 }
1366 }
1367
1368 void HeapShared::resolve_classes_for_subgraphs(JavaThread* current, ArchivableStaticFieldInfo fields[]) {
1369 for (int i = 0; fields[i].valid(); i++) {
1370 ArchivableStaticFieldInfo* info = &fields[i];
1371 TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name);
1372 InstanceKlass* k = SystemDictionaryShared::find_builtin_class(klass_name);
1373 assert(k != nullptr && k->defined_by_boot_loader(), "sanity");
1374 resolve_classes_for_subgraph_of(current, k);
1375 }
1376 }
1377
1378 void HeapShared::resolve_classes_for_subgraph_of(JavaThread* current, Klass* k) {
1379 JavaThread* THREAD = current;
1380 ExceptionMark em(THREAD);
1381 const ArchivedKlassSubGraphInfoRecord* record =
1382 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/false, THREAD);
1383 if (HAS_PENDING_EXCEPTION) {
1384 CLEAR_PENDING_EXCEPTION;
1385 }
1386 if (record == nullptr) {
1387 clear_archived_roots_of(k);
1388 }
1389 }
1390
1391 void HeapShared::initialize_java_lang_invoke(TRAPS) {
1392 if (CDSConfig::is_using_aot_linked_classes() || CDSConfig::is_dumping_method_handles()) {
1393 resolve_or_init("java/lang/invoke/Invokers$Holder", true, CHECK);
1394 resolve_or_init("java/lang/invoke/MethodHandle", true, CHECK);
1395 resolve_or_init("java/lang/invoke/MethodHandleNatives", true, CHECK);
1396 resolve_or_init("java/lang/invoke/DirectMethodHandle$Holder", true, CHECK);
1397 resolve_or_init("java/lang/invoke/DelegatingMethodHandle$Holder", true, CHECK);
1398 resolve_or_init("java/lang/invoke/LambdaForm$Holder", true, CHECK);
1399 resolve_or_init("java/lang/invoke/BoundMethodHandle$Species_L", true, CHECK);
1400 }
1401 }
1402
1403 // Initialize the InstanceKlasses of objects that are reachable from the following roots:
1404 // - interned strings
1405 // - Klass::java_mirror() -- including aot-initialized mirrors such as those of Enum klasses.
1406 // - ConstantPool::resolved_references()
1407 // - Universe::<xxx>_exception_instance()
1408 //
1409 // For example, if this enum class is initialized at AOT cache assembly time:
1410 //
1411 // enum Fruit {
1412 // APPLE, ORANGE, BANANA;
1413 // static final Set<Fruit> HAVE_SEEDS = new HashSet<>(Arrays.asList(APPLE, ORANGE));
1414 // }
1415 //
1416 // the aot-initialized mirror of Fruit has a static field that references HashSet, which
1417 // should be initialized before any Java code can access the Fruit class. Note that
1418 // HashSet itself doesn't necessary need to be an aot-initialized class.
1419 void HeapShared::init_classes_for_special_subgraph(Handle class_loader, TRAPS) {
1420 if (!is_archived_heap_in_use()) {
1421 return;
1422 }
1423
1424 assert( _run_time_special_subgraph != nullptr, "must be");
1425 Array<Klass*>* klasses = _run_time_special_subgraph->subgraph_object_klasses();
1426 if (klasses != nullptr) {
1427 for (int pass = 0; pass < 2; pass ++) {
1428 for (int i = 0; i < klasses->length(); i++) {
1429 Klass* k = klasses->at(i);
1430 if (k->class_loader_data() == nullptr) {
1431 // This class is not yet loaded. We will initialize it in a later phase.
1432 // For example, we have loaded only AOTLinkedClassCategory::BOOT1 classes
1433 // but k is part of AOTLinkedClassCategory::BOOT2.
1434 continue;
1435 }
1436 if (k->class_loader() == class_loader()) {
1437 if (pass == 0) {
1438 if (k->is_instance_klass()) {
1439 InstanceKlass::cast(k)->link_class(CHECK);
1440 }
1441 } else {
1442 resolve_or_init(k, /*do_init*/true, CHECK);
1443 }
1444 }
1445 }
1446 }
1447 }
1448 }
1449
1450 void HeapShared::initialize_from_archived_subgraph(JavaThread* current, Klass* k) {
1451 JavaThread* THREAD = current;
1452 if (!CDSConfig::is_using_klass_subgraphs()) {
1453 return; // nothing to do
1454 }
1455
1456 if (k->name()->equals("jdk/internal/module/ArchivedModuleGraph") &&
1457 !CDSConfig::is_using_optimized_module_handling() &&
1458 // archive was created with --module-path
1459 AOTClassLocationConfig::runtime()->num_module_paths() > 0) {
1460 // ArchivedModuleGraph was created with a --module-path that's different than the runtime --module-path.
1461 // Thus, it might contain references to modules that do not exist at runtime. We cannot use it.
1462 log_info(aot, heap)("Skip initializing ArchivedModuleGraph subgraph: is_using_optimized_module_handling=%s num_module_paths=%d",
1463 BOOL_TO_STR(CDSConfig::is_using_optimized_module_handling()),
1464 AOTClassLocationConfig::runtime()->num_module_paths());
1465 return;
1466 }
1467
1468 ExceptionMark em(THREAD);
1469 const ArchivedKlassSubGraphInfoRecord* record =
1470 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/true, THREAD);
1471
1472 if (HAS_PENDING_EXCEPTION) {
1473 CLEAR_PENDING_EXCEPTION;
1474 // None of the field value will be set if there was an exception when initializing the classes.
1475 // The java code will not see any of the archived objects in the
1476 // subgraphs referenced from k in this case.
1477 return;
1478 }
1479
1480 if (record != nullptr) {
1481 init_archived_fields_for(k, record);
1482 }
1483 }
1484
1485 const ArchivedKlassSubGraphInfoRecord*
1486 HeapShared::resolve_or_init_classes_for_subgraph_of(Klass* k, bool do_init, TRAPS) {
1487 assert(!CDSConfig::is_dumping_heap(), "Should not be called when dumping heap");
1488
1489 if (!k->in_aot_cache()) {
1490 return nullptr;
1491 }
1492 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary_quick(k);
1493 const ArchivedKlassSubGraphInfoRecord* record = _run_time_subgraph_info_table.lookup(k, hash, 0);
1494
1495 #ifndef PRODUCT
1496 if (_test_class_name != nullptr && k->name()->equals(_test_class_name) && record != nullptr) {
1497 _test_class = k;
1498 _test_class_record = record;
1499 }
1500 #endif
1501
1502 // Initialize from archived data. Currently this is done only
1503 // during VM initialization time. No lock is needed.
1504 if (record == nullptr) {
1505 if (log_is_enabled(Info, aot, heap)) {
1506 ResourceMark rm(THREAD);
1507 log_info(aot, heap)("subgraph %s is not recorded",
1508 k->external_name());
1509 }
1510 return nullptr;
1511 } else {
1512 if (record->is_full_module_graph() && !CDSConfig::is_using_full_module_graph()) {
1513 if (log_is_enabled(Info, aot, heap)) {
1514 ResourceMark rm(THREAD);
1515 log_info(aot, heap)("subgraph %s cannot be used because full module graph is disabled",
1516 k->external_name());
1517 }
1518 return nullptr;
1519 }
1520
1521 if (record->has_non_early_klasses() && JvmtiExport::should_post_class_file_load_hook()) {
1522 if (log_is_enabled(Info, aot, heap)) {
1523 ResourceMark rm(THREAD);
1524 log_info(aot, heap)("subgraph %s cannot be used because JVMTI ClassFileLoadHook is enabled",
1525 k->external_name());
1526 }
1527 return nullptr;
1528 }
1529
1530 if (log_is_enabled(Info, aot, heap)) {
1531 ResourceMark rm;
1532 log_info(aot, heap)("%s subgraph %s ", do_init ? "init" : "resolve", k->external_name());
1533 }
1534
1535 resolve_or_init(k, do_init, CHECK_NULL);
1536
1537 // Load/link/initialize the klasses of the objects in the subgraph.
1538 // nullptr class loader is used.
1539 Array<Klass*>* klasses = record->subgraph_object_klasses();
1540 if (klasses != nullptr) {
1541 for (int i = 0; i < klasses->length(); i++) {
1542 Klass* klass = klasses->at(i);
1543 if (!klass->in_aot_cache()) {
1544 return nullptr;
1545 }
1546 resolve_or_init(klass, do_init, CHECK_NULL);
1547 }
1548 }
1549 }
1550
1551 return record;
1552 }
1553
1554 void HeapShared::resolve_or_init(const char* klass_name, bool do_init, TRAPS) {
1555 TempNewSymbol klass_name_sym = SymbolTable::new_symbol(klass_name);
1556 InstanceKlass* k = SystemDictionaryShared::find_builtin_class(klass_name_sym);
1557 if (k == nullptr) {
1558 return;
1559 }
1560 assert(k->defined_by_boot_loader(), "sanity");
1561 resolve_or_init(k, false, CHECK);
1562 if (do_init) {
1563 resolve_or_init(k, true, CHECK);
1564 }
1565 }
1566
1567 void HeapShared::resolve_or_init(Klass* k, bool do_init, TRAPS) {
1568 if (!do_init) {
1569 if (k->class_loader_data() == nullptr) {
1570 Klass* resolved_k = SystemDictionary::resolve_or_null(k->name(), CHECK);
1571 assert(resolved_k == k, "classes used by archived heap must not be replaced by JVMTI ClassFileLoadHook");
1572 }
1573 } else {
1574 assert(k->class_loader_data() != nullptr, "must have been resolved by HeapShared::resolve_classes");
1575 if (k->is_instance_klass()) {
1576 InstanceKlass* ik = InstanceKlass::cast(k);
1577 ik->initialize(CHECK);
1578 } else if (k->is_objArray_klass()) {
1579 ObjArrayKlass* oak = ObjArrayKlass::cast(k);
1580 oak->initialize(CHECK);
1581 }
1582 }
1583 }
1584
1585 void HeapShared::init_archived_fields_for(Klass* k, const ArchivedKlassSubGraphInfoRecord* record) {
1586 verify_the_heap(k, "before");
1587
1588 Array<int>* entry_field_records = record->entry_field_records();
1589 if (entry_field_records != nullptr) {
1590 int efr_len = entry_field_records->length();
1591 assert(efr_len % 2 == 0, "sanity");
1592 for (int i = 0; i < efr_len; i += 2) {
1593 int field_offset = entry_field_records->at(i);
1594 int root_index = entry_field_records->at(i+1);
1595 // Load the subgraph entry fields from the record and store them back to
1596 // the corresponding fields within the mirror.
1597 oop v = get_root(root_index, /*clear=*/true);
1598 oop m = k->java_mirror();
1599 if (k->has_aot_initialized_mirror()) {
1600 assert(v == m->obj_field(field_offset), "must be aot-initialized");
1601 } else {
1602 m->obj_field_put(field_offset, v);
1603 }
1604 log_debug(aot, heap)(" " PTR_FORMAT " init field @ %2d = " PTR_FORMAT, p2i(k), field_offset, p2i(v));
1605 }
1606
1607 // Done. Java code can see the archived sub-graphs referenced from k's
1608 // mirror after this point.
1609 if (log_is_enabled(Info, aot, heap)) {
1610 ResourceMark rm;
1611 log_info(aot, heap)("initialize_from_archived_subgraph %s " PTR_FORMAT "%s%s",
1612 k->external_name(), p2i(k), JvmtiExport::is_early_phase() ? " (early)" : "",
1613 k->has_aot_initialized_mirror() ? " (aot-inited)" : "");
1614 }
1615 }
1616
1617 verify_the_heap(k, "after ");
1618 }
1619
1620 void HeapShared::clear_archived_roots_of(Klass* k) {
1621 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary_quick(k);
1622 const ArchivedKlassSubGraphInfoRecord* record = _run_time_subgraph_info_table.lookup(k, hash, 0);
1623 if (record != nullptr) {
1624 Array<int>* entry_field_records = record->entry_field_records();
1625 if (entry_field_records != nullptr) {
1626 int efr_len = entry_field_records->length();
1627 assert(efr_len % 2 == 0, "sanity");
1628 for (int i = 0; i < efr_len; i += 2) {
1629 int root_index = entry_field_records->at(i+1);
1630 clear_root(root_index);
1631 }
1632 }
1633 }
1634 }
1635
1636 // Push all oop fields (or oop array elemenets in case of an objArray) in
1637 // _referencing_obj onto the _stack.
1638 class HeapShared::OopFieldPusher: public BasicOopIterateClosure {
1639 PendingOopStack* _stack;
1640 GrowableArray<oop> _found_oop_fields;
1641 int _level;
1642 bool _record_klasses_only;
1643 KlassSubGraphInfo* _subgraph_info;
1644 oop _referencing_obj;
1645 bool _is_java_lang_ref;
1646 public:
1647 OopFieldPusher(PendingOopStack* stack,
1648 int level,
1649 bool record_klasses_only,
1650 KlassSubGraphInfo* subgraph_info,
1651 oop orig) :
1652 _stack(stack),
1653 _found_oop_fields(),
1654 _level(level),
1655 _record_klasses_only(record_klasses_only),
1656 _subgraph_info(subgraph_info),
1657 _referencing_obj(orig) {
1658 _is_java_lang_ref = AOTReferenceObjSupport::check_if_ref_obj(orig);
1659 }
1660 void do_oop(narrowOop *p) { OopFieldPusher::do_oop_work(p); }
1661 void do_oop( oop *p) { OopFieldPusher::do_oop_work(p); }
1662
1663 ~OopFieldPusher() {
1664 while (_found_oop_fields.length() > 0) {
1665 // This produces the exact same traversal order as the previous version
1666 // of OopFieldPusher that recurses on the C stack -- a depth-first search,
1667 // walking the oop fields in _referencing_obj by ascending field offsets.
1668 oop obj = _found_oop_fields.pop();
1669 _stack->push(PendingOop(obj, _referencing_obj, _level + 1));
1670 }
1671 }
1672
1673 protected:
1674 template <class T> void do_oop_work(T *p) {
1675 int field_offset = pointer_delta_as_int((char*)p, cast_from_oop<char*>(_referencing_obj));
1676 oop obj = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_load_at(_referencing_obj, field_offset);
1677 if (obj != nullptr) {
1678 if (_is_java_lang_ref && AOTReferenceObjSupport::skip_field(field_offset)) {
1679 // Do not follow these fields. They will be cleared to null.
1680 return;
1681 }
1682
1683 if (!_record_klasses_only && log_is_enabled(Debug, aot, heap)) {
1684 ResourceMark rm;
1685 log_debug(aot, heap)("(%d) %s[%d] ==> " PTR_FORMAT " size %zu %s", _level,
1686 _referencing_obj->klass()->external_name(), field_offset,
1687 p2i(obj), obj->size() * HeapWordSize, obj->klass()->external_name());
1688 if (log_is_enabled(Trace, aot, heap)) {
1689 LogTarget(Trace, aot, heap) log;
1690 LogStream out(log);
1691 obj->print_on(&out);
1692 }
1693 }
1694
1695 _found_oop_fields.push(obj);
1696 }
1697 }
1698
1699 public:
1700 oop referencing_obj() { return _referencing_obj; }
1701 KlassSubGraphInfo* subgraph_info() { return _subgraph_info; }
1702 };
1703
1704 // Checks if an oop has any non-null oop fields
1705 class PointsToOopsChecker : public BasicOopIterateClosure {
1706 bool _result;
1707
1708 template <class T> void check(T *p) {
1709 _result |= (HeapAccess<>::oop_load(p) != nullptr);
1710 }
1711
1712 public:
1713 PointsToOopsChecker() : _result(false) {}
1714 void do_oop(narrowOop *p) { check(p); }
1715 void do_oop( oop *p) { check(p); }
1716 bool result() { return _result; }
1717 };
1718
1719 HeapShared::CachedOopInfo HeapShared::make_cached_oop_info(oop obj, oop referrer) {
1720 PointsToOopsChecker points_to_oops_checker;
1721 obj->oop_iterate(&points_to_oops_checker);
1722 return CachedOopInfo(OopHandle(Universe::vm_global(), referrer), points_to_oops_checker.result());
1723 }
1724
1725 void HeapShared::init_box_classes(TRAPS) {
1726 if (is_archived_heap_in_use()) {
1727 vmClasses::Boolean_klass()->initialize(CHECK);
1728 vmClasses::Character_klass()->initialize(CHECK);
1729 vmClasses::Float_klass()->initialize(CHECK);
1730 vmClasses::Double_klass()->initialize(CHECK);
1731 vmClasses::Byte_klass()->initialize(CHECK);
1732 vmClasses::Short_klass()->initialize(CHECK);
1733 vmClasses::Integer_klass()->initialize(CHECK);
1734 vmClasses::Long_klass()->initialize(CHECK);
1735 vmClasses::Void_klass()->initialize(CHECK);
1736 }
1737 }
1738
1739 // (1) If orig_obj has not been archived yet, archive it.
1740 // (2) If orig_obj has not been seen yet (since start_recording_subgraph() was called),
1741 // trace all objects that are reachable from it, and make sure these objects are archived.
1742 // (3) Record the klasses of all objects that are reachable from orig_obj (including those that
1743 // were already archived when this function is called)
1744 bool HeapShared::archive_reachable_objects_from(int level,
1745 KlassSubGraphInfo* subgraph_info,
1746 oop orig_obj) {
1747 assert(orig_obj != nullptr, "must be");
1748 PendingOopStack stack;
1749 stack.push(PendingOop(orig_obj, nullptr, level));
1750
1751 while (stack.length() > 0) {
1752 PendingOop po = stack.pop();
1753 _object_being_archived = po;
1754 bool status = walk_one_object(&stack, po.level(), subgraph_info, po.obj(), po.referrer());
1755 _object_being_archived = PendingOop();
1756
1757 if (!status) {
1758 // Don't archive a subgraph root that's too big. For archives static fields, that's OK
1759 // as the Java code will take care of initializing this field dynamically.
1760 assert(level == 1, "VM should have exited with unarchivable objects for _level > 1");
1761 return false;
1762 }
1763 }
1764
1765 return true;
1766 }
1767
1768 bool HeapShared::walk_one_object(PendingOopStack* stack, int level, KlassSubGraphInfo* subgraph_info,
1769 oop orig_obj, oop referrer) {
1770 assert(orig_obj != nullptr, "must be");
1771 if (!JavaClasses::is_supported_for_archiving(orig_obj)) {
1772 // This object has injected fields that cannot be supported easily, so we disallow them for now.
1773 // If you get an error here, you probably made a change in the JDK library that has added
1774 // these objects that are referenced (directly or indirectly) by static fields.
1775 ResourceMark rm;
1776 log_error(aot, heap)("Cannot archive object " PTR_FORMAT " of class %s", p2i(orig_obj), orig_obj->klass()->external_name());
1777 debug_trace();
1778 AOTMetaspace::unrecoverable_writing_error();
1779 }
1780
1781 if (log_is_enabled(Debug, aot, heap) && java_lang_Class::is_instance(orig_obj)) {
1782 ResourceMark rm;
1783 LogTarget(Debug, aot, heap) log;
1784 LogStream out(log);
1785 out.print("Found java mirror " PTR_FORMAT " ", p2i(orig_obj));
1786 Klass* k = java_lang_Class::as_Klass(orig_obj);
1787 if (k != nullptr) {
1788 out.print("%s", k->external_name());
1789 } else {
1790 out.print("primitive");
1791 }
1792 out.print_cr("; scratch mirror = " PTR_FORMAT,
1793 p2i(scratch_java_mirror(orig_obj)));
1794 }
1795
1796 if (java_lang_Class::is_instance(orig_obj)) {
1797 Klass* k = java_lang_Class::as_Klass(orig_obj);
1798 if (RegeneratedClasses::has_been_regenerated(k)) {
1799 orig_obj = RegeneratedClasses::get_regenerated_object(k)->java_mirror();
1800 }
1801 }
1802
1803 if (CDSConfig::is_dumping_aot_linked_classes()) {
1804 if (java_lang_Class::is_instance(orig_obj)) {
1805 orig_obj = scratch_java_mirror(orig_obj);
1806 assert(orig_obj != nullptr, "must be archived");
1807 }
1808 } else if (java_lang_Class::is_instance(orig_obj) && subgraph_info != _dump_time_special_subgraph) {
1809 // Without CDSConfig::is_dumping_aot_linked_classes(), we only allow archived objects to
1810 // point to the mirrors of (1) j.l.Object, (2) primitive classes, and (3) box classes. These are initialized
1811 // very early by HeapShared::init_box_classes().
1812 if (orig_obj == vmClasses::Object_klass()->java_mirror()
1813 || java_lang_Class::is_primitive(orig_obj)
1814 || orig_obj == vmClasses::Boolean_klass()->java_mirror()
1815 || orig_obj == vmClasses::Character_klass()->java_mirror()
1816 || orig_obj == vmClasses::Float_klass()->java_mirror()
1817 || orig_obj == vmClasses::Double_klass()->java_mirror()
1818 || orig_obj == vmClasses::Byte_klass()->java_mirror()
1819 || orig_obj == vmClasses::Short_klass()->java_mirror()
1820 || orig_obj == vmClasses::Integer_klass()->java_mirror()
1821 || orig_obj == vmClasses::Long_klass()->java_mirror()
1822 || orig_obj == vmClasses::Void_klass()->java_mirror()) {
1823 orig_obj = scratch_java_mirror(orig_obj);
1824 assert(orig_obj != nullptr, "must be archived");
1825 } else {
1826 // If you get an error here, you probably made a change in the JDK library that has added a Class
1827 // object that is referenced (directly or indirectly) by an ArchivableStaticFieldInfo
1828 // defined at the top of this file.
1829 log_error(aot, heap)("(%d) Unknown java.lang.Class object is in the archived sub-graph", level);
1830 debug_trace();
1831 AOTMetaspace::unrecoverable_writing_error();
1832 }
1833 }
1834
1835 if (has_been_seen_during_subgraph_recording(orig_obj)) {
1836 // orig_obj has already been archived and traced. Nothing more to do.
1837 return true;
1838 } else {
1839 set_has_been_seen_during_subgraph_recording(orig_obj);
1840 }
1841
1842 bool already_archived = has_been_archived(orig_obj);
1843 bool record_klasses_only = already_archived;
1844 if (!already_archived) {
1845 ++_num_new_archived_objs;
1846 if (!archive_object(orig_obj, referrer, subgraph_info)) {
1847 // Skip archiving the sub-graph referenced from the current entry field.
1848 ResourceMark rm;
1849 log_error(aot, heap)(
1850 "Cannot archive the sub-graph referenced from %s object ("
1851 PTR_FORMAT ") size %zu, skipped.",
1852 orig_obj->klass()->external_name(), p2i(orig_obj), orig_obj->size() * HeapWordSize);
1853 if (level == 1) {
1854 // Don't archive a subgraph root that's too big. For archives static fields, that's OK
1855 // as the Java code will take care of initializing this field dynamically.
1856 return false;
1857 } else {
1858 // We don't know how to handle an object that has been archived, but some of its reachable
1859 // objects cannot be archived. Bail out for now. We might need to fix this in the future if
1860 // we have a real use case.
1861 AOTMetaspace::unrecoverable_writing_error();
1862 }
1863 }
1864 }
1865
1866 Klass *orig_k = orig_obj->klass();
1867 subgraph_info->add_subgraph_object_klass(orig_k);
1868
1869 {
1870 // Find all the oops that are referenced by orig_obj, push them onto the stack
1871 // so we can work on them next.
1872 ResourceMark rm;
1873 OopFieldPusher pusher(stack, level, record_klasses_only, subgraph_info, orig_obj);
1874 orig_obj->oop_iterate(&pusher);
1875 }
1876
1877 if (CDSConfig::is_dumping_aot_linked_classes()) {
1878 // The enum klasses are archived with aot-initialized mirror.
1879 // See AOTClassInitializer::can_archive_initialized_mirror().
1880 } else {
1881 // This is legacy support for enum classes before JEP 483 -- we cannot rerun
1882 // the enum's <clinit> in the production run, so special handling is needed.
1883 if (CDSEnumKlass::is_enum_obj(orig_obj)) {
1884 CDSEnumKlass::handle_enum_obj(level + 1, subgraph_info, orig_obj);
1885 }
1886 }
1887
1888 return true;
1889 }
1890
1891 //
1892 // Start from the given static field in a java mirror and archive the
1893 // complete sub-graph of java heap objects that are reached directly
1894 // or indirectly from the starting object by following references.
1895 // Sub-graph archiving restrictions (current):
1896 //
1897 // - All classes of objects in the archived sub-graph (including the
1898 // entry class) must be boot class only.
1899 // - No java.lang.Class instance (java mirror) can be included inside
1900 // an archived sub-graph. Mirror can only be the sub-graph entry object.
1901 //
1902 // The Java heap object sub-graph archiving process (see OopFieldPusher):
1903 //
1904 // 1) Java object sub-graph archiving starts from a given static field
1905 // within a Class instance (java mirror). If the static field is a
1906 // reference field and points to a non-null java object, proceed to
1907 // the next step.
1908 //
1909 // 2) Archives the referenced java object. If an archived copy of the
1910 // current object already exists, updates the pointer in the archived
1911 // copy of the referencing object to point to the current archived object.
1912 // Otherwise, proceed to the next step.
1913 //
1914 // 3) Follows all references within the current java object and recursively
1915 // archive the sub-graph of objects starting from each reference.
1916 //
1917 // 4) Updates the pointer in the archived copy of referencing object to
1918 // point to the current archived object.
1919 //
1920 // 5) The Klass of the current java object is added to the list of Klasses
1921 // for loading and initializing before any object in the archived graph can
1922 // be accessed at runtime.
1923 //
1924 void HeapShared::archive_reachable_objects_from_static_field(InstanceKlass *k,
1925 const char* klass_name,
1926 int field_offset,
1927 const char* field_name) {
1928 precond(CDSConfig::is_dumping_klass_subgraphs());
1929 assert(k->defined_by_boot_loader(), "must be boot class");
1930
1931 oop m = k->java_mirror();
1932
1933 KlassSubGraphInfo* subgraph_info = get_subgraph_info(k);
1934 oop f = m->obj_field(field_offset);
1935
1936 log_debug(aot, heap)("Start archiving from: %s::%s (" PTR_FORMAT ")", klass_name, field_name, p2i(f));
1937
1938 if (!CompressedOops::is_null(f)) {
1939 if (log_is_enabled(Trace, aot, heap)) {
1940 LogTarget(Trace, aot, heap) log;
1941 LogStream out(log);
1942 f->print_on(&out);
1943 }
1944
1945 bool success = archive_reachable_objects_from(1, subgraph_info, f);
1946 if (!success) {
1947 log_error(aot, heap)("Archiving failed %s::%s (some reachable objects cannot be archived)",
1948 klass_name, field_name);
1949 } else {
1950 // Note: the field value is not preserved in the archived mirror.
1951 // Record the field as a new subGraph entry point. The recorded
1952 // information is restored from the archive at runtime.
1953 subgraph_info->add_subgraph_entry_field(field_offset, f);
1954 log_info(aot, heap)("Archived field %s::%s => " PTR_FORMAT, klass_name, field_name, p2i(f));
1955 }
1956 } else {
1957 // The field contains null, we still need to record the entry point,
1958 // so it can be restored at runtime.
1959 subgraph_info->add_subgraph_entry_field(field_offset, nullptr);
1960 }
1961 }
1962
1963 #ifndef PRODUCT
1964 class VerifySharedOopClosure: public BasicOopIterateClosure {
1965 public:
1966 void do_oop(narrowOop *p) { VerifySharedOopClosure::do_oop_work(p); }
1967 void do_oop( oop *p) { VerifySharedOopClosure::do_oop_work(p); }
1968
1969 protected:
1970 template <class T> void do_oop_work(T *p) {
1971 oop obj = HeapAccess<>::oop_load(p);
1972 if (obj != nullptr) {
1973 HeapShared::verify_reachable_objects_from(obj);
1974 }
1975 }
1976 };
1977
1978 void HeapShared::verify_subgraph_from_static_field(InstanceKlass* k, int field_offset) {
1979 precond(CDSConfig::is_dumping_klass_subgraphs());
1980 assert(k->defined_by_boot_loader(), "must be boot class");
1981
1982 oop m = k->java_mirror();
1983 oop f = m->obj_field(field_offset);
1984 if (!CompressedOops::is_null(f)) {
1985 verify_subgraph_from(f);
1986 }
1987 }
1988
1989 void HeapShared::verify_subgraph_from(oop orig_obj) {
1990 if (!has_been_archived(orig_obj)) {
1991 // It's OK for the root of a subgraph to be not archived. See comments in
1992 // archive_reachable_objects_from().
1993 return;
1994 }
1995
1996 // Verify that all objects reachable from orig_obj are archived.
1997 init_seen_objects_table();
1998 verify_reachable_objects_from(orig_obj);
1999 delete_seen_objects_table();
2000 }
2001
2002 void HeapShared::verify_reachable_objects_from(oop obj) {
2003 _num_total_verifications ++;
2004 if (java_lang_Class::is_instance(obj)) {
2005 Klass* k = java_lang_Class::as_Klass(obj);
2006 if (RegeneratedClasses::has_been_regenerated(k)) {
2007 k = RegeneratedClasses::get_regenerated_object(k);
2008 obj = k->java_mirror();
2009 }
2010 obj = scratch_java_mirror(obj);
2011 assert(obj != nullptr, "must be");
2012 }
2013 if (!has_been_seen_during_subgraph_recording(obj)) {
2014 set_has_been_seen_during_subgraph_recording(obj);
2015 assert(has_been_archived(obj), "must be");
2016 VerifySharedOopClosure walker;
2017 obj->oop_iterate(&walker);
2018 }
2019 }
2020 #endif
2021
2022 void HeapShared::check_special_subgraph_classes() {
2023 if (CDSConfig::is_dumping_aot_linked_classes()) {
2024 // We can have aot-initialized classes (such as Enums) that can reference objects
2025 // of arbitrary types. Currently, we trust the JEP 483 implementation to only
2026 // aot-initialize classes that are "safe".
2027 //
2028 // TODO: we need an automatic tool that checks the safety of aot-initialized
2029 // classes (when we extend the set of aot-initialized classes beyond JEP 483)
2030 return;
2031 } else {
2032 // In this case, the special subgraph should contain a few specific types
2033 GrowableArray<Klass*>* klasses = _dump_time_special_subgraph->subgraph_object_klasses();
2034 int num = klasses->length();
2035 for (int i = 0; i < num; i++) {
2036 Klass* subgraph_k = klasses->at(i);
2037 Symbol* name = subgraph_k->name();
2038 if (subgraph_k->is_instance_klass() &&
2039 name != vmSymbols::java_lang_Class() &&
2040 name != vmSymbols::java_lang_String() &&
2041 name != vmSymbols::java_lang_ArithmeticException() &&
2042 name != vmSymbols::java_lang_ArrayIndexOutOfBoundsException() &&
2043 name != vmSymbols::java_lang_ArrayStoreException() &&
2044 name != vmSymbols::java_lang_ClassCastException() &&
2045 name != vmSymbols::java_lang_InternalError() &&
2046 name != vmSymbols::java_lang_NullPointerException() &&
2047 name != vmSymbols::jdk_internal_vm_PreemptedException()) {
2048 ResourceMark rm;
2049 fatal("special subgraph cannot have objects of type %s", subgraph_k->external_name());
2050 }
2051 }
2052 }
2053 }
2054
2055 HeapShared::SeenObjectsTable* HeapShared::_seen_objects_table = nullptr;
2056 HeapShared::PendingOop HeapShared::_object_being_archived;
2057 size_t HeapShared::_num_new_walked_objs;
2058 size_t HeapShared::_num_new_archived_objs;
2059 size_t HeapShared::_num_old_recorded_klasses;
2060
2061 size_t HeapShared::_num_total_subgraph_recordings = 0;
2062 size_t HeapShared::_num_total_walked_objs = 0;
2063 size_t HeapShared::_num_total_archived_objs = 0;
2064 size_t HeapShared::_num_total_recorded_klasses = 0;
2065 size_t HeapShared::_num_total_verifications = 0;
2066
2067 bool HeapShared::has_been_seen_during_subgraph_recording(oop obj) {
2068 return _seen_objects_table->get(obj) != nullptr;
2069 }
2070
2071 void HeapShared::set_has_been_seen_during_subgraph_recording(oop obj) {
2072 assert(!has_been_seen_during_subgraph_recording(obj), "sanity");
2073 _seen_objects_table->put_when_absent(obj, true);
2074 _seen_objects_table->maybe_grow();
2075 ++ _num_new_walked_objs;
2076 }
2077
2078 void HeapShared::start_recording_subgraph(InstanceKlass *k, const char* class_name, bool is_full_module_graph) {
2079 log_info(aot, heap)("Start recording subgraph(s) for archived fields in %s", class_name);
2080 init_subgraph_info(k, is_full_module_graph);
2081 init_seen_objects_table();
2082 _num_new_walked_objs = 0;
2083 _num_new_archived_objs = 0;
2084 _num_old_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses();
2085 }
2086
2087 void HeapShared::done_recording_subgraph(InstanceKlass *k, const char* class_name) {
2088 size_t num_new_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses() -
2089 _num_old_recorded_klasses;
2090 log_info(aot, heap)("Done recording subgraph(s) for archived fields in %s: "
2091 "walked %zu objs, archived %zu new objs, recorded %zu classes",
2092 class_name, _num_new_walked_objs, _num_new_archived_objs,
2093 num_new_recorded_klasses);
2094
2095 delete_seen_objects_table();
2096
2097 _num_total_subgraph_recordings ++;
2098 _num_total_walked_objs += _num_new_walked_objs;
2099 _num_total_archived_objs += _num_new_archived_objs;
2100 _num_total_recorded_klasses += num_new_recorded_klasses;
2101 }
2102
2103 class ArchivableStaticFieldFinder: public FieldClosure {
2104 InstanceKlass* _ik;
2105 Symbol* _field_name;
2106 bool _found;
2107 int _offset;
2108 public:
2109 ArchivableStaticFieldFinder(InstanceKlass* ik, Symbol* field_name) :
2110 _ik(ik), _field_name(field_name), _found(false), _offset(-1) {}
2111
2112 virtual void do_field(fieldDescriptor* fd) {
2113 if (fd->name() == _field_name) {
2114 assert(!_found, "fields can never be overloaded");
2115 if (is_reference_type(fd->field_type())) {
2116 _found = true;
2117 _offset = fd->offset();
2118 }
2119 }
2120 }
2121 bool found() { return _found; }
2122 int offset() { return _offset; }
2123 };
2124
2125 void HeapShared::init_subgraph_entry_fields(ArchivableStaticFieldInfo fields[],
2126 TRAPS) {
2127 for (int i = 0; fields[i].valid(); i++) {
2128 ArchivableStaticFieldInfo* info = &fields[i];
2129 TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name);
2130 TempNewSymbol field_name = SymbolTable::new_symbol(info->field_name);
2131 ResourceMark rm; // for stringStream::as_string() etc.
2132
2133 #ifndef PRODUCT
2134 bool is_test_class = (ArchiveHeapTestClass != nullptr) && (strcmp(info->klass_name, ArchiveHeapTestClass) == 0);
2135 const char* test_class_name = ArchiveHeapTestClass;
2136 #else
2137 bool is_test_class = false;
2138 const char* test_class_name = ""; // avoid C++ printf checks warnings.
2139 #endif
2140
2141 if (is_test_class) {
2142 log_warning(aot)("Loading ArchiveHeapTestClass %s ...", test_class_name);
2143 }
2144
2145 Klass* k = SystemDictionary::resolve_or_fail(klass_name, true, THREAD);
2146 if (HAS_PENDING_EXCEPTION) {
2147 CLEAR_PENDING_EXCEPTION;
2148 stringStream st;
2149 st.print("Fail to initialize archive heap: %s cannot be loaded by the boot loader", info->klass_name);
2150 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
2151 }
2152
2153 if (!k->is_instance_klass()) {
2154 stringStream st;
2155 st.print("Fail to initialize archive heap: %s is not an instance class", info->klass_name);
2156 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
2157 }
2158
2159 InstanceKlass* ik = InstanceKlass::cast(k);
2160 assert(InstanceKlass::cast(ik)->defined_by_boot_loader(),
2161 "Only support boot classes");
2162
2163 if (is_test_class) {
2164 if (ik->module()->is_named()) {
2165 // We don't want ArchiveHeapTestClass to be abused to easily load/initialize arbitrary
2166 // core-lib classes. You need to at least append to the bootclasspath.
2167 stringStream st;
2168 st.print("ArchiveHeapTestClass %s is not in unnamed module", test_class_name);
2169 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
2170 }
2171
2172 if (ik->package() != nullptr) {
2173 // This restriction makes HeapShared::is_a_test_class_in_unnamed_module() easy.
2174 stringStream st;
2175 st.print("ArchiveHeapTestClass %s is not in unnamed package", test_class_name);
2176 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
2177 }
2178 } else {
2179 if (ik->module()->name() != vmSymbols::java_base()) {
2180 // We don't want to deal with cases when a module is unavailable at runtime.
2181 // FUTURE -- load from archived heap only when module graph has not changed
2182 // between dump and runtime.
2183 stringStream st;
2184 st.print("%s is not in java.base module", info->klass_name);
2185 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
2186 }
2187 }
2188
2189 if (is_test_class) {
2190 log_warning(aot)("Initializing ArchiveHeapTestClass %s ...", test_class_name);
2191 }
2192 ik->initialize(CHECK);
2193
2194 ArchivableStaticFieldFinder finder(ik, field_name);
2195 ik->do_local_static_fields(&finder);
2196 if (!finder.found()) {
2197 stringStream st;
2198 st.print("Unable to find the static T_OBJECT field %s::%s", info->klass_name, info->field_name);
2199 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
2200 }
2201
2202 info->klass = ik;
2203 info->offset = finder.offset();
2204 }
2205 }
2206
2207 void HeapShared::init_subgraph_entry_fields(TRAPS) {
2208 assert(CDSConfig::is_dumping_heap(), "must be");
2209 _dump_time_subgraph_info_table = new (mtClass)DumpTimeKlassSubGraphInfoTable();
2210 if (CDSConfig::is_dumping_klass_subgraphs()) {
2211 init_subgraph_entry_fields(archive_subgraph_entry_fields, CHECK);
2212 if (CDSConfig::is_dumping_full_module_graph()) {
2213 init_subgraph_entry_fields(fmg_archive_subgraph_entry_fields, CHECK);
2214 }
2215 }
2216 }
2217
2218 #ifndef PRODUCT
2219 void HeapShared::setup_test_class(const char* test_class_name) {
2220 ArchivableStaticFieldInfo* p = archive_subgraph_entry_fields;
2221 int num_slots = sizeof(archive_subgraph_entry_fields) / sizeof(ArchivableStaticFieldInfo);
2222 assert(p[num_slots - 2].klass_name == nullptr, "must have empty slot that's patched below");
2223 assert(p[num_slots - 1].klass_name == nullptr, "must have empty slot that marks the end of the list");
2224
2225 if (test_class_name != nullptr) {
2226 p[num_slots - 2].klass_name = test_class_name;
2227 p[num_slots - 2].field_name = ARCHIVE_TEST_FIELD_NAME;
2228 }
2229 }
2230
2231 // See if ik is one of the test classes that are pulled in by -XX:ArchiveHeapTestClass
2232 // during runtime. This may be called before the module system is initialized so
2233 // we cannot rely on InstanceKlass::module(), etc.
2234 bool HeapShared::is_a_test_class_in_unnamed_module(Klass* ik) {
2235 if (_test_class != nullptr) {
2236 if (ik == _test_class) {
2237 return true;
2238 }
2239 Array<Klass*>* klasses = _test_class_record->subgraph_object_klasses();
2240 if (klasses == nullptr) {
2241 return false;
2242 }
2243
2244 for (int i = 0; i < klasses->length(); i++) {
2245 Klass* k = klasses->at(i);
2246 if (k == ik) {
2247 Symbol* name;
2248 if (k->is_instance_klass()) {
2249 name = InstanceKlass::cast(k)->name();
2250 } else if (k->is_objArray_klass()) {
2251 Klass* bk = ObjArrayKlass::cast(k)->bottom_klass();
2252 if (!bk->is_instance_klass()) {
2253 return false;
2254 }
2255 name = bk->name();
2256 } else {
2257 return false;
2258 }
2259
2260 // See KlassSubGraphInfo::check_allowed_klass() - we only allow test classes
2261 // to be:
2262 // (A) java.base classes (which must not be in the unnamed module)
2263 // (B) test classes which must be in the unnamed package of the unnamed module.
2264 // So if we see a '/' character in the class name, it must be in (A);
2265 // otherwise it must be in (B).
2266 if (name->index_of_at(0, "/", 1) >= 0) {
2267 return false; // (A)
2268 }
2269
2270 return true; // (B)
2271 }
2272 }
2273 }
2274
2275 return false;
2276 }
2277
2278 void HeapShared::initialize_test_class_from_archive(JavaThread* current) {
2279 Klass* k = _test_class;
2280 if (k != nullptr && is_archived_heap_in_use()) {
2281 JavaThread* THREAD = current;
2282 ExceptionMark em(THREAD);
2283 const ArchivedKlassSubGraphInfoRecord* record =
2284 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/false, THREAD);
2285
2286 // The _test_class is in the unnamed module, so it can't call CDS.initializeFromArchive()
2287 // from its <clinit> method. So we set up its "archivedObjects" field first, before
2288 // calling its <clinit>. This is not strictly clean, but it's a convenient way to write unit
2289 // test cases (see test/hotspot/jtreg/runtime/cds/appcds/cacheObject/ArchiveHeapTestClass.java).
2290 if (record != nullptr) {
2291 init_archived_fields_for(k, record);
2292 }
2293 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/true, THREAD);
2294 }
2295 }
2296 #endif
2297
2298 void HeapShared::init_for_dumping(TRAPS) {
2299 if (CDSConfig::is_dumping_heap()) {
2300 setup_test_class(ArchiveHeapTestClass);
2301 init_subgraph_entry_fields(CHECK);
2302 }
2303 }
2304
2305 void HeapShared::init_heap_writer() {
2306 if (HeapShared::is_writing_streaming_mode()) {
2307 AOTStreamedHeapWriter::init();
2308 } else {
2309 AOTMappedHeapWriter::init();
2310 }
2311 }
2312
2313 void HeapShared::archive_object_subgraphs(ArchivableStaticFieldInfo fields[],
2314 bool is_full_module_graph) {
2315 _num_total_subgraph_recordings = 0;
2316 _num_total_walked_objs = 0;
2317 _num_total_archived_objs = 0;
2318 _num_total_recorded_klasses = 0;
2319 _num_total_verifications = 0;
2320
2321 // For each class X that has one or more archived fields:
2322 // [1] Dump the subgraph of each archived field
2323 // [2] Create a list of all the class of the objects that can be reached
2324 // by any of these static fields.
2325 // At runtime, these classes are initialized before X's archived fields
2326 // are restored by HeapShared::initialize_from_archived_subgraph().
2327 for (int i = 0; fields[i].valid(); ) {
2328 ArchivableStaticFieldInfo* info = &fields[i];
2329 const char* klass_name = info->klass_name;
2330 start_recording_subgraph(info->klass, klass_name, is_full_module_graph);
2331
2332 // If you have specified consecutive fields of the same klass in
2333 // fields[], these will be archived in the same
2334 // {start_recording_subgraph ... done_recording_subgraph} pass to
2335 // save time.
2336 for (; fields[i].valid(); i++) {
2337 ArchivableStaticFieldInfo* f = &fields[i];
2338 if (f->klass_name != klass_name) {
2339 break;
2340 }
2341
2342 archive_reachable_objects_from_static_field(f->klass, f->klass_name,
2343 f->offset, f->field_name);
2344 }
2345 done_recording_subgraph(info->klass, klass_name);
2346 }
2347
2348 log_info(aot, heap)("Archived subgraph records = %zu",
2349 _num_total_subgraph_recordings);
2350 log_info(aot, heap)(" Walked %zu objects", _num_total_walked_objs);
2351 log_info(aot, heap)(" Archived %zu objects", _num_total_archived_objs);
2352 log_info(aot, heap)(" Recorded %zu klasses", _num_total_recorded_klasses);
2353
2354 #ifndef PRODUCT
2355 for (int i = 0; fields[i].valid(); i++) {
2356 ArchivableStaticFieldInfo* f = &fields[i];
2357 verify_subgraph_from_static_field(f->klass, f->offset);
2358 }
2359 log_info(aot, heap)(" Verified %zu references", _num_total_verifications);
2360 #endif
2361 }
2362
2363 bool HeapShared::is_interned_string(oop obj) {
2364 if (!java_lang_String::is_instance(obj)) {
2365 return false;
2366 }
2367
2368 ResourceMark rm;
2369 int len = 0;
2370 jchar* name = java_lang_String::as_unicode_string_or_null(obj, len);
2371 if (name == nullptr) {
2372 fatal("Insufficient memory for dumping");
2373 }
2374 return StringTable::lookup(name, len) == obj;
2375 }
2376
2377 bool HeapShared::is_dumped_interned_string(oop o) {
2378 return is_interned_string(o) && has_been_archived(o);
2379 }
2380
2381 // These tables should be used only within the CDS safepoint, so
2382 // delete them before we exit the safepoint. Otherwise the table will
2383 // contain bad oops after a GC.
2384 void HeapShared::delete_tables_with_raw_oops() {
2385 assert(_seen_objects_table == nullptr, "should have been deleted");
2386
2387 if (is_writing_mapping_mode()) {
2388 AOTMappedHeapWriter::delete_tables_with_raw_oops();
2389 } else {
2390 assert(is_writing_streaming_mode(), "what other mode?");
2391 AOTStreamedHeapWriter::delete_tables_with_raw_oops();
2392 }
2393 }
2394
2395 void HeapShared::debug_trace() {
2396 ResourceMark rm;
2397 oop referrer = _object_being_archived.referrer();
2398 if (referrer != nullptr) {
2399 LogStream ls(Log(aot, heap)::error());
2400 ls.print_cr("Reference trace");
2401 CDSHeapVerifier::trace_to_root(&ls, referrer);
2402 }
2403 }
2404
2405 #ifndef PRODUCT
2406 // At dump-time, find the location of all the non-null oop pointers in an archived heap
2407 // region. This way we can quickly relocate all the pointers without using
2408 // BasicOopIterateClosure at runtime.
2409 class FindEmbeddedNonNullPointers: public BasicOopIterateClosure {
2410 void* _start;
2411 BitMap *_oopmap;
2412 size_t _num_total_oops;
2413 size_t _num_null_oops;
2414 public:
2415 FindEmbeddedNonNullPointers(void* start, BitMap* oopmap)
2416 : _start(start), _oopmap(oopmap), _num_total_oops(0), _num_null_oops(0) {}
2417
2418 virtual void do_oop(narrowOop* p) {
2419 assert(UseCompressedOops, "sanity");
2420 _num_total_oops ++;
2421 narrowOop v = *p;
2422 if (!CompressedOops::is_null(v)) {
2423 size_t idx = p - (narrowOop*)_start;
2424 _oopmap->set_bit(idx);
2425 } else {
2426 _num_null_oops ++;
2427 }
2428 }
2429 virtual void do_oop(oop* p) {
2430 assert(!UseCompressedOops, "sanity");
2431 _num_total_oops ++;
2432 if ((*p) != nullptr) {
2433 size_t idx = p - (oop*)_start;
2434 _oopmap->set_bit(idx);
2435 } else {
2436 _num_null_oops ++;
2437 }
2438 }
2439 size_t num_total_oops() const { return _num_total_oops; }
2440 size_t num_null_oops() const { return _num_null_oops; }
2441 };
2442 #endif
2443
2444 void HeapShared::count_allocation(size_t size) {
2445 _total_obj_count ++;
2446 _total_obj_size += size;
2447 for (int i = 0; i < ALLOC_STAT_SLOTS; i++) {
2448 if (size <= (size_t(1) << i)) {
2449 _alloc_count[i] ++;
2450 _alloc_size[i] += size;
2451 return;
2452 }
2453 }
2454 }
2455
2456 static double avg_size(size_t size, size_t count) {
2457 double avg = 0;
2458 if (count > 0) {
2459 avg = double(size * HeapWordSize) / double(count);
2460 }
2461 return avg;
2462 }
2463
2464 void HeapShared::print_stats() {
2465 size_t huge_count = _total_obj_count;
2466 size_t huge_size = _total_obj_size;
2467
2468 for (int i = 0; i < ALLOC_STAT_SLOTS; i++) {
2469 size_t byte_size_limit = (size_t(1) << i) * HeapWordSize;
2470 size_t count = _alloc_count[i];
2471 size_t size = _alloc_size[i];
2472 log_info(aot, heap)("%8zu objects are <= %-6zu"
2473 " bytes (total %8zu bytes, avg %8.1f bytes)",
2474 count, byte_size_limit, size * HeapWordSize, avg_size(size, count));
2475 huge_count -= count;
2476 huge_size -= size;
2477 }
2478
2479 log_info(aot, heap)("%8zu huge objects (total %8zu bytes"
2480 ", avg %8.1f bytes)",
2481 huge_count, huge_size * HeapWordSize,
2482 avg_size(huge_size, huge_count));
2483 log_info(aot, heap)("%8zu total objects (total %8zu bytes"
2484 ", avg %8.1f bytes)",
2485 _total_obj_count, _total_obj_size * HeapWordSize,
2486 avg_size(_total_obj_size, _total_obj_count));
2487 }
2488
2489 bool HeapShared::is_metadata_field(oop src_obj, int offset) {
2490 bool result = false;
2491 do_metadata_offsets(src_obj, [&](int metadata_offset) {
2492 if (metadata_offset == offset) {
2493 result = true;
2494 }
2495 });
2496 return result;
2497 }
2498
2499 void HeapShared::remap_dumped_metadata(oop src_obj, address archived_object) {
2500 do_metadata_offsets(src_obj, [&](int offset) {
2501 Metadata** buffered_field_addr = (Metadata**)(archived_object + offset);
2502 Metadata* native_ptr = *buffered_field_addr;
2503
2504 if (native_ptr == nullptr) {
2505 return;
2506 }
2507
2508 if (RegeneratedClasses::has_been_regenerated(native_ptr)) {
2509 native_ptr = RegeneratedClasses::get_regenerated_object(native_ptr);
2510 }
2511
2512 address buffered_native_ptr = ArchiveBuilder::current()->get_buffered_addr((address)native_ptr);
2513 address requested_native_ptr = ArchiveBuilder::current()->to_requested(buffered_native_ptr);
2514 *buffered_field_addr = (Metadata*)requested_native_ptr;
2515 });
2516 }
2517
2518 bool HeapShared::is_archived_boot_layer_available(JavaThread* current) {
2519 TempNewSymbol klass_name = SymbolTable::new_symbol(ARCHIVED_BOOT_LAYER_CLASS);
2520 InstanceKlass* k = SystemDictionary::find_instance_klass(current, klass_name, Handle());
2521 if (k == nullptr) {
2522 return false;
2523 } else {
2524 TempNewSymbol field_name = SymbolTable::new_symbol(ARCHIVED_BOOT_LAYER_FIELD);
2525 TempNewSymbol field_signature = SymbolTable::new_symbol("Ljdk/internal/module/ArchivedBootLayer;");
2526 fieldDescriptor fd;
2527 if (k->find_field(field_name, field_signature, true, &fd) != nullptr) {
2528 oop m = k->java_mirror();
2529 oop f = m->obj_field(fd.offset());
2530 if (CompressedOops::is_null(f)) {
2531 return false;
2532 }
2533 } else {
2534 return false;
2535 }
2536 }
2537 return true;
2538 }
2539
2540 #endif // INCLUDE_CDS_JAVA_HEAP