1 /*
2 * Copyright (c) 2018, 2023, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "cds/archiveBuilder.hpp"
27 #include "cds/archiveHeapLoader.hpp"
28 #include "cds/archiveHeapWriter.hpp"
29 #include "cds/archiveUtils.hpp"
30 #include "cds/cdsHeapVerifier.hpp"
31 #include "cds/heapShared.hpp"
32 #include "cds/metaspaceShared.hpp"
33 #include "classfile/classLoaderData.hpp"
34 #include "classfile/javaClasses.inline.hpp"
35 #include "classfile/modules.hpp"
36 #include "classfile/stringTable.hpp"
37 #include "classfile/symbolTable.hpp"
38 #include "classfile/systemDictionary.hpp"
39 #include "classfile/systemDictionaryShared.hpp"
40 #include "classfile/vmClasses.hpp"
41 #include "classfile/vmSymbols.hpp"
42 #include "gc/shared/collectedHeap.hpp"
43 #include "gc/shared/gcLocker.hpp"
44 #include "gc/shared/gcVMOperations.hpp"
45 #include "logging/log.hpp"
46 #include "logging/logStream.hpp"
47 #include "memory/iterator.inline.hpp"
48 #include "memory/resourceArea.hpp"
49 #include "memory/universe.hpp"
50 #include "oops/compressedOops.inline.hpp"
51 #include "oops/fieldStreams.inline.hpp"
52 #include "oops/objArrayOop.inline.hpp"
53 #include "oops/oop.inline.hpp"
54 #include "oops/typeArrayOop.inline.hpp"
55 #include "prims/jvmtiExport.hpp"
56 #include "runtime/fieldDescriptor.inline.hpp"
57 #include "runtime/init.hpp"
58 #include "runtime/javaCalls.hpp"
59 #include "runtime/safepoint.hpp"
60 #include "runtime/mutexLocker.hpp"
61 #include "runtime/safepointVerifiers.hpp"
62 #include "utilities/bitMap.inline.hpp"
63 #include "utilities/copy.hpp"
64 #if INCLUDE_G1GC
65 #include "gc/g1/g1CollectedHeap.hpp"
66 #endif
67
68 #if INCLUDE_CDS_JAVA_HEAP
69
70 struct ArchivableStaticFieldInfo {
71 const char* klass_name;
72 const char* field_name;
73 InstanceKlass* klass;
74 int offset;
75 BasicType type;
76
77 ArchivableStaticFieldInfo(const char* k, const char* f)
78 : klass_name(k), field_name(f), klass(nullptr), offset(0), type(T_ILLEGAL) {}
79
80 bool valid() {
81 return klass_name != nullptr;
82 }
83 };
84
85 bool HeapShared::_disable_writing = false;
86 DumpedInternedStrings *HeapShared::_dumped_interned_strings = nullptr;
87
88 size_t HeapShared::_alloc_count[HeapShared::ALLOC_STAT_SLOTS];
89 size_t HeapShared::_alloc_size[HeapShared::ALLOC_STAT_SLOTS];
90 size_t HeapShared::_total_obj_count;
91 size_t HeapShared::_total_obj_size;
92
93 #ifndef PRODUCT
94 #define ARCHIVE_TEST_FIELD_NAME "archivedObjects"
95 static Array<char>* _archived_ArchiveHeapTestClass = nullptr;
96 static const char* _test_class_name = nullptr;
97 static const Klass* _test_class = nullptr;
98 static const ArchivedKlassSubGraphInfoRecord* _test_class_record = nullptr;
99 #endif
100
101
102 //
103 // If you add new entries to the following tables, you should know what you're doing!
104 //
105
106 static ArchivableStaticFieldInfo archive_subgraph_entry_fields[] = {
107 {"java/lang/Integer$IntegerCache", "archivedCache"},
108 {"java/lang/Long$LongCache", "archivedCache"},
109 {"java/lang/Byte$ByteCache", "archivedCache"},
110 {"java/lang/Short$ShortCache", "archivedCache"},
111 {"java/lang/Character$CharacterCache", "archivedCache"},
112 {"java/util/jar/Attributes$Name", "KNOWN_NAMES"},
113 {"sun/util/locale/BaseLocale", "constantBaseLocales"},
114 {"jdk/internal/module/ArchivedModuleGraph", "archivedModuleGraph"},
115 {"java/util/ImmutableCollections", "archivedObjects"},
116 {"java/lang/ModuleLayer", "EMPTY_LAYER"},
117 {"java/lang/module/Configuration", "EMPTY_CONFIGURATION"},
118 {"jdk/internal/math/FDBigInteger", "archivedCaches"},
119 #ifndef PRODUCT
120 {nullptr, nullptr}, // Extra slot for -XX:ArchiveHeapTestClass
121 #endif
122 {nullptr, nullptr},
123 };
124
125 // full module graph
126 static ArchivableStaticFieldInfo fmg_archive_subgraph_entry_fields[] = {
127 {"jdk/internal/loader/ArchivedClassLoaders", "archivedClassLoaders"},
128 {"jdk/internal/module/ArchivedBootLayer", "archivedBootLayer"},
129 {"java/lang/Module$ArchivedData", "archivedData"},
130 {nullptr, nullptr},
131 };
132
133 KlassSubGraphInfo* HeapShared::_default_subgraph_info;
134 GrowableArrayCHeap<oop, mtClassShared>* HeapShared::_pending_roots = nullptr;
135 OopHandle HeapShared::_roots;
136 OopHandle HeapShared::_scratch_basic_type_mirrors[T_VOID+1];
137 KlassToOopHandleTable* HeapShared::_scratch_java_mirror_table = nullptr;
138
139 static bool is_subgraph_root_class_of(ArchivableStaticFieldInfo fields[], InstanceKlass* ik) {
140 for (int i = 0; fields[i].valid(); i++) {
141 if (fields[i].klass == ik) {
142 return true;
143 }
144 }
145 return false;
146 }
147
148 bool HeapShared::is_subgraph_root_class(InstanceKlass* ik) {
149 return is_subgraph_root_class_of(archive_subgraph_entry_fields, ik) ||
150 is_subgraph_root_class_of(fmg_archive_subgraph_entry_fields, ik);
151 }
152
153 unsigned HeapShared::oop_hash(oop const& p) {
154 // Do not call p->identity_hash() as that will update the
155 // object header.
156 return primitive_hash(cast_from_oop<intptr_t>(p));
157 }
158
159 static void reset_states(oop obj, TRAPS) {
160 Handle h_obj(THREAD, obj);
161 InstanceKlass* klass = InstanceKlass::cast(obj->klass());
162 TempNewSymbol method_name = SymbolTable::new_symbol("resetArchivedStates");
163 Symbol* method_sig = vmSymbols::void_method_signature();
164
165 while (klass != nullptr) {
166 Method* method = klass->find_method(method_name, method_sig);
167 if (method != nullptr) {
168 assert(method->is_private(), "must be");
169 if (log_is_enabled(Debug, cds)) {
170 ResourceMark rm(THREAD);
171 log_debug(cds)(" calling %s", method->name_and_sig_as_C_string());
172 }
173 JavaValue result(T_VOID);
174 JavaCalls::call_special(&result, h_obj, klass,
175 method_name, method_sig, CHECK);
176 }
177 klass = klass->java_super();
178 }
179 }
180
181 void HeapShared::reset_archived_object_states(TRAPS) {
182 assert(DumpSharedSpaces, "dump-time only");
183 log_debug(cds)("Resetting platform loader");
184 reset_states(SystemDictionary::java_platform_loader(), CHECK);
185 log_debug(cds)("Resetting system loader");
186 reset_states(SystemDictionary::java_system_loader(), CHECK);
187
188 // Clean up jdk.internal.loader.ClassLoaders::bootLoader(), which is not
189 // directly used for class loading, but rather is used by the core library
190 // to keep track of resources, etc, loaded by the null class loader.
191 //
192 // Note, this object is non-null, and is not the same as
193 // ClassLoaderData::the_null_class_loader_data()->class_loader(),
194 // which is null.
195 log_debug(cds)("Resetting boot loader");
196 JavaValue result(T_OBJECT);
197 JavaCalls::call_static(&result,
198 vmClasses::jdk_internal_loader_ClassLoaders_klass(),
199 vmSymbols::bootLoader_name(),
200 vmSymbols::void_BuiltinClassLoader_signature(),
201 CHECK);
202 Handle boot_loader(THREAD, result.get_oop());
203 reset_states(boot_loader(), CHECK);
204 }
205
206 HeapShared::ArchivedObjectCache* HeapShared::_archived_object_cache = nullptr;
207
208 bool HeapShared::has_been_archived(oop obj) {
209 assert(DumpSharedSpaces, "dump-time only");
210 return archived_object_cache()->get(obj) != nullptr;
211 }
212
213 int HeapShared::append_root(oop obj) {
214 assert(DumpSharedSpaces, "dump-time only");
215
216 // No GC should happen since we aren't scanning _pending_roots.
217 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
218
219 if (_pending_roots == nullptr) {
220 _pending_roots = new GrowableArrayCHeap<oop, mtClassShared>(500);
221 }
222
223 return _pending_roots->append(obj);
224 }
225
226 objArrayOop HeapShared::roots() {
227 if (DumpSharedSpaces) {
228 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
229 if (!HeapShared::can_write()) {
230 return nullptr;
231 }
232 } else {
233 assert(UseSharedSpaces, "must be");
234 }
235
236 objArrayOop roots = (objArrayOop)_roots.resolve();
237 assert(roots != nullptr, "should have been initialized");
238 return roots;
239 }
240
241 // Returns an objArray that contains all the roots of the archived objects
242 oop HeapShared::get_root(int index, bool clear) {
243 assert(index >= 0, "sanity");
244 assert(!DumpSharedSpaces && UseSharedSpaces, "runtime only");
245 assert(!_roots.is_empty(), "must have loaded shared heap");
246 oop result = roots()->obj_at(index);
247 if (clear) {
248 clear_root(index);
249 }
250 return result;
251 }
252
253 void HeapShared::clear_root(int index) {
254 assert(index >= 0, "sanity");
255 assert(UseSharedSpaces, "must be");
256 if (ArchiveHeapLoader::is_in_use()) {
257 if (log_is_enabled(Debug, cds, heap)) {
258 oop old = roots()->obj_at(index);
259 log_debug(cds, heap)("Clearing root %d: was " PTR_FORMAT, index, p2i(old));
260 }
261 roots()->obj_at_put(index, nullptr);
262 }
263 }
264
265 bool HeapShared::archive_object(oop obj) {
266 assert(DumpSharedSpaces, "dump-time only");
267
268 assert(!obj->is_stackChunk(), "do not archive stack chunks");
269 if (has_been_archived(obj)) {
270 return true;
271 }
272
273 if (ArchiveHeapWriter::is_too_large_to_archive(obj->size())) {
274 log_debug(cds, heap)("Cannot archive, object (" PTR_FORMAT ") is too large: " SIZE_FORMAT,
275 p2i(obj), obj->size());
276 return false;
277 } else {
278 count_allocation(obj->size());
279 ArchiveHeapWriter::add_source_obj(obj);
280
281 // The archived objects are discovered in a predictable order. Compute
282 // their identity_hash() as soon as we see them. This ensures that the
283 // the identity_hash in the object header will have a predictable value,
284 // making the archive reproducible.
285 obj->identity_hash();
286 CachedOopInfo info = make_cached_oop_info();
287 archived_object_cache()->put(obj, info);
288 mark_native_pointers(obj);
289
290 if (log_is_enabled(Debug, cds, heap)) {
291 ResourceMark rm;
292 log_debug(cds, heap)("Archived heap object " PTR_FORMAT " : %s",
293 p2i(obj), obj->klass()->external_name());
294 }
295
296 if (java_lang_Module::is_instance(obj)) {
297 if (Modules::check_module_oop(obj)) {
298 Modules::update_oops_in_archived_module(obj, append_root(obj));
299 }
300 java_lang_Module::set_module_entry(obj, nullptr);
301 } else if (java_lang_ClassLoader::is_instance(obj)) {
302 // class_data will be restored explicitly at run time.
303 guarantee(obj == SystemDictionary::java_platform_loader() ||
304 obj == SystemDictionary::java_system_loader() ||
305 java_lang_ClassLoader::loader_data(obj) == nullptr, "must be");
306 java_lang_ClassLoader::release_set_loader_data(obj, nullptr);
307 }
308
309 return true;
310 }
311 }
312
313 class KlassToOopHandleTable: public ResourceHashtable<Klass*, OopHandle,
314 36137, // prime number
315 AnyObj::C_HEAP,
316 mtClassShared> {
317 public:
318 oop get_oop(Klass* k) {
319 MutexLocker ml(ScratchObjects_lock, Mutex::_no_safepoint_check_flag);
320 OopHandle* handle = get(k);
321 if (handle != nullptr) {
322 return handle->resolve();
323 } else {
324 return nullptr;
325 }
326 }
327 void set_oop(Klass* k, oop o) {
328 MutexLocker ml(ScratchObjects_lock, Mutex::_no_safepoint_check_flag);
329 OopHandle handle(Universe::vm_global(), o);
330 bool is_new = put(k, handle);
331 assert(is_new, "cannot set twice");
332 }
333 void remove_oop(Klass* k) {
334 MutexLocker ml(ScratchObjects_lock, Mutex::_no_safepoint_check_flag);
335 OopHandle* handle = get(k);
336 if (handle != nullptr) {
337 handle->release(Universe::vm_global());
338 remove(k);
339 }
340 }
341 };
342
343 void HeapShared::init_scratch_objects(TRAPS) {
344 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
345 BasicType bt = (BasicType)i;
346 if (!is_reference_type(bt)) {
347 oop m = java_lang_Class::create_basic_type_mirror(type2name(bt), bt, CHECK);
348 _scratch_basic_type_mirrors[i] = OopHandle(Universe::vm_global(), m);
349 }
350 }
351 _scratch_java_mirror_table = new (mtClass)KlassToOopHandleTable();
352 }
353
354 oop HeapShared::scratch_java_mirror(BasicType t) {
355 assert((uint)t < T_VOID+1, "range check");
356 assert(!is_reference_type(t), "sanity");
357 return _scratch_basic_type_mirrors[t].resolve();
358 }
359
360 oop HeapShared::scratch_java_mirror(Klass* k) {
361 return _scratch_java_mirror_table->get_oop(k);
362 }
363
364 void HeapShared::set_scratch_java_mirror(Klass* k, oop mirror) {
365 _scratch_java_mirror_table->set_oop(k, mirror);
366 }
367
368 void HeapShared::remove_scratch_objects(Klass* k) {
369 _scratch_java_mirror_table->remove_oop(k);
370 }
371
372 void HeapShared::archive_java_mirrors() {
373 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
374 BasicType bt = (BasicType)i;
375 if (!is_reference_type(bt)) {
376 oop m = _scratch_basic_type_mirrors[i].resolve();
377 assert(m != nullptr, "sanity");
378 bool success = archive_reachable_objects_from(1, _default_subgraph_info, m);
379 assert(success, "sanity");
380
381 log_trace(cds, heap, mirror)(
382 "Archived %s mirror object from " PTR_FORMAT,
383 type2name(bt), p2i(m));
384
385 Universe::set_archived_basic_type_mirror_index(bt, append_root(m));
386 }
387 }
388
389 GrowableArray<Klass*>* klasses = ArchiveBuilder::current()->klasses();
390 assert(klasses != nullptr, "sanity");
391 for (int i = 0; i < klasses->length(); i++) {
392 Klass* orig_k = klasses->at(i);
393 oop m = scratch_java_mirror(orig_k);
394 if (m != nullptr) {
395 Klass* buffered_k = ArchiveBuilder::get_buffered_klass(orig_k);
396 bool success = archive_reachable_objects_from(1, _default_subgraph_info, m);
397 guarantee(success, "scratch mirrors must point to only archivable objects");
398 buffered_k->set_archived_java_mirror(append_root(m));
399 ResourceMark rm;
400 log_trace(cds, heap, mirror)(
401 "Archived %s mirror object from " PTR_FORMAT,
402 buffered_k->external_name(), p2i(m));
403
404 // archive the resolved_referenes array
405 if (buffered_k->is_instance_klass()) {
406 InstanceKlass* ik = InstanceKlass::cast(buffered_k);
407 oop rr = ik->constants()->prepare_resolved_references_for_archiving();
408 if (rr != nullptr && !ArchiveHeapWriter::is_too_large_to_archive(rr)) {
409 bool success = HeapShared::archive_reachable_objects_from(1, _default_subgraph_info, rr);
410 assert(success, "must be");
411 int root_index = append_root(rr);
412 ik->constants()->cache()->set_archived_references(root_index);
413 }
414 }
415 }
416 }
417 }
418
419 void HeapShared::archive_strings() {
420 oop shared_strings_array = StringTable::init_shared_table(_dumped_interned_strings);
421 bool success = archive_reachable_objects_from(1, _default_subgraph_info, shared_strings_array);
422 // We must succeed because:
423 // - _dumped_interned_strings do not contain any large strings.
424 // - StringTable::init_shared_table() doesn't create any large arrays.
425 assert(success, "shared strings array must not point to arrays or strings that are too large to archive");
426 StringTable::set_shared_strings_array_index(append_root(shared_strings_array));
427 }
428
429 void HeapShared::mark_native_pointers(oop orig_obj) {
430 if (java_lang_Class::is_instance(orig_obj)) {
431 ArchiveHeapWriter::mark_native_pointer(orig_obj, java_lang_Class::klass_offset());
432 ArchiveHeapWriter::mark_native_pointer(orig_obj, java_lang_Class::array_klass_offset());
433 }
434 }
435
436 // -- Handling of Enum objects
437 // Java Enum classes have synthetic <clinit> methods that look like this
438 // enum MyEnum {FOO, BAR}
439 // MyEnum::<clinint> {
440 // /*static final MyEnum*/ MyEnum::FOO = new MyEnum("FOO");
441 // /*static final MyEnum*/ MyEnum::BAR = new MyEnum("BAR");
442 // }
443 //
444 // If MyEnum::FOO object is referenced by any of the archived subgraphs, we must
445 // ensure the archived value equals (in object address) to the runtime value of
446 // MyEnum::FOO.
447 //
448 // However, since MyEnum::<clinint> is synthetically generated by javac, there's
449 // no way of programmatically handling this inside the Java code (as you would handle
450 // ModuleLayer::EMPTY_LAYER, for example).
451 //
452 // Instead, we archive all static field of such Enum classes. At runtime,
453 // HeapShared::initialize_enum_klass() will skip the <clinit> method and pull
454 // the static fields out of the archived heap.
455 void HeapShared::check_enum_obj(int level,
456 KlassSubGraphInfo* subgraph_info,
457 oop orig_obj) {
458 assert(level > 1, "must never be called at the first (outermost) level");
459 Klass* k = orig_obj->klass();
460 Klass* buffered_k = ArchiveBuilder::get_buffered_klass(k);
461 if (!k->is_instance_klass()) {
462 return;
463 }
464 InstanceKlass* ik = InstanceKlass::cast(k);
465 if (ik->java_super() == vmClasses::Enum_klass() && !ik->has_archived_enum_objs()) {
466 ResourceMark rm;
467 ik->set_has_archived_enum_objs();
468 buffered_k->set_has_archived_enum_objs();
469 oop mirror = ik->java_mirror();
470
471 for (JavaFieldStream fs(ik); !fs.done(); fs.next()) {
472 if (fs.access_flags().is_static()) {
473 fieldDescriptor& fd = fs.field_descriptor();
474 if (fd.field_type() != T_OBJECT && fd.field_type() != T_ARRAY) {
475 guarantee(false, "static field %s::%s must be T_OBJECT or T_ARRAY",
476 ik->external_name(), fd.name()->as_C_string());
477 }
478 oop oop_field = mirror->obj_field(fd.offset());
479 if (oop_field == nullptr) {
480 guarantee(false, "static field %s::%s must not be null",
481 ik->external_name(), fd.name()->as_C_string());
482 } else if (oop_field->klass() != ik && oop_field->klass() != ik->array_klass_or_null()) {
483 guarantee(false, "static field %s::%s is of the wrong type",
484 ik->external_name(), fd.name()->as_C_string());
485 }
486 bool success = archive_reachable_objects_from(level, subgraph_info, oop_field);
487 assert(success, "VM should have exited with unarchivable objects for _level > 1");
488 int root_index = append_root(oop_field);
489 log_info(cds, heap)("Archived enum obj @%d %s::%s (" INTPTR_FORMAT ")",
490 root_index, ik->external_name(), fd.name()->as_C_string(),
491 p2i((oopDesc*)oop_field));
492 SystemDictionaryShared::add_enum_klass_static_field(ik, root_index);
493 }
494 }
495 }
496 }
497
498 // See comments in HeapShared::check_enum_obj()
499 bool HeapShared::initialize_enum_klass(InstanceKlass* k, TRAPS) {
500 if (!ArchiveHeapLoader::is_in_use()) {
501 return false;
502 }
503
504 RunTimeClassInfo* info = RunTimeClassInfo::get_for(k);
505 assert(info != nullptr, "sanity");
506
507 if (log_is_enabled(Info, cds, heap)) {
508 ResourceMark rm;
509 log_info(cds, heap)("Initializing Enum class: %s", k->external_name());
510 }
511
512 oop mirror = k->java_mirror();
513 int i = 0;
514 for (JavaFieldStream fs(k); !fs.done(); fs.next()) {
515 if (fs.access_flags().is_static()) {
516 int root_index = info->enum_klass_static_field_root_index_at(i++);
517 fieldDescriptor& fd = fs.field_descriptor();
518 assert(fd.field_type() == T_OBJECT || fd.field_type() == T_ARRAY, "must be");
519 mirror->obj_field_put(fd.offset(), get_root(root_index, /*clear=*/true));
520 }
521 }
522 return true;
523 }
524
525 void HeapShared::archive_objects(ArchiveHeapInfo *heap_info) {
526 {
527 NoSafepointVerifier nsv;
528
529 _default_subgraph_info = init_subgraph_info(vmClasses::Object_klass(), false);
530
531 // Cache for recording where the archived objects are copied to
532 create_archived_object_cache();
533
534 log_info(cds)("Heap range = [" PTR_FORMAT " - " PTR_FORMAT "]",
535 UseCompressedOops ? p2i(CompressedOops::begin()) :
536 p2i((address)G1CollectedHeap::heap()->reserved().start()),
537 UseCompressedOops ? p2i(CompressedOops::end()) :
538 p2i((address)G1CollectedHeap::heap()->reserved().end()));
539 copy_objects();
540
541 CDSHeapVerifier::verify();
542 check_default_subgraph_classes();
543 }
544
545 ArchiveHeapWriter::write(_pending_roots, heap_info);
546 }
547
548 void HeapShared::copy_interned_strings() {
549 init_seen_objects_table();
550
551 auto copier = [&] (oop s, bool value_ignored) {
552 assert(s != nullptr, "sanity");
553 assert(!ArchiveHeapWriter::is_string_too_large_to_archive(s), "large strings must have been filtered");
554 bool success = archive_reachable_objects_from(1, _default_subgraph_info, s);
555 assert(success, "must be");
556 // Prevent string deduplication from changing the value field to
557 // something not in the archive.
558 java_lang_String::set_deduplication_forbidden(s);
559 };
560 _dumped_interned_strings->iterate_all(copier);
561
562 delete_seen_objects_table();
563 }
564
565 void HeapShared::copy_special_objects() {
566 // Archive special objects that do not belong to any subgraphs
567 init_seen_objects_table();
568 archive_java_mirrors();
569 archive_strings();
570 delete_seen_objects_table();
571 }
572
573 void HeapShared::copy_objects() {
574 assert(HeapShared::can_write(), "must be");
575
576 copy_interned_strings();
577 copy_special_objects();
578
579 archive_object_subgraphs(archive_subgraph_entry_fields,
580 false /* is_full_module_graph */);
581
582 if (MetaspaceShared::use_full_module_graph()) {
583 archive_object_subgraphs(fmg_archive_subgraph_entry_fields,
584 true /* is_full_module_graph */);
585 Modules::verify_archived_modules();
586 }
587 }
588
589 //
590 // Subgraph archiving support
591 //
592 HeapShared::DumpTimeKlassSubGraphInfoTable* HeapShared::_dump_time_subgraph_info_table = nullptr;
593 HeapShared::RunTimeKlassSubGraphInfoTable HeapShared::_run_time_subgraph_info_table;
594
595 // Get the subgraph_info for Klass k. A new subgraph_info is created if
596 // there is no existing one for k. The subgraph_info records the "buffered"
597 // address of the class.
598 KlassSubGraphInfo* HeapShared::init_subgraph_info(Klass* k, bool is_full_module_graph) {
599 assert(DumpSharedSpaces, "dump time only");
600 bool created;
601 Klass* buffered_k = ArchiveBuilder::get_buffered_klass(k);
602 KlassSubGraphInfo* info =
603 _dump_time_subgraph_info_table->put_if_absent(k, KlassSubGraphInfo(buffered_k, is_full_module_graph),
604 &created);
605 assert(created, "must not initialize twice");
606 return info;
607 }
608
609 KlassSubGraphInfo* HeapShared::get_subgraph_info(Klass* k) {
610 assert(DumpSharedSpaces, "dump time only");
611 KlassSubGraphInfo* info = _dump_time_subgraph_info_table->get(k);
612 assert(info != nullptr, "must have been initialized");
613 return info;
614 }
615
616 // Add an entry field to the current KlassSubGraphInfo.
617 void KlassSubGraphInfo::add_subgraph_entry_field(int static_field_offset, oop v) {
618 assert(DumpSharedSpaces, "dump time only");
619 if (_subgraph_entry_fields == nullptr) {
620 _subgraph_entry_fields =
621 new (mtClass) GrowableArray<int>(10, mtClass);
622 }
623 _subgraph_entry_fields->append(static_field_offset);
624 _subgraph_entry_fields->append(HeapShared::append_root(v));
625 }
626
627 // Add the Klass* for an object in the current KlassSubGraphInfo's subgraphs.
628 // Only objects of boot classes can be included in sub-graph.
629 void KlassSubGraphInfo::add_subgraph_object_klass(Klass* orig_k) {
630 assert(DumpSharedSpaces, "dump time only");
631 Klass* buffered_k = ArchiveBuilder::get_buffered_klass(orig_k);
632
633 if (_subgraph_object_klasses == nullptr) {
634 _subgraph_object_klasses =
635 new (mtClass) GrowableArray<Klass*>(50, mtClass);
636 }
637
638 assert(ArchiveBuilder::current()->is_in_buffer_space(buffered_k), "must be a shared class");
639
640 if (_k == buffered_k) {
641 // Don't add the Klass containing the sub-graph to it's own klass
642 // initialization list.
643 return;
644 }
645
646 if (buffered_k->is_instance_klass()) {
647 assert(InstanceKlass::cast(buffered_k)->is_shared_boot_class(),
648 "must be boot class");
649 // vmClasses::xxx_klass() are not updated, need to check
650 // the original Klass*
651 if (orig_k == vmClasses::String_klass() ||
652 orig_k == vmClasses::Object_klass()) {
653 // Initialized early during VM initialization. No need to be added
654 // to the sub-graph object class list.
655 return;
656 }
657 check_allowed_klass(InstanceKlass::cast(orig_k));
658 } else if (buffered_k->is_objArray_klass()) {
659 Klass* abk = ObjArrayKlass::cast(buffered_k)->bottom_klass();
660 if (abk->is_instance_klass()) {
661 assert(InstanceKlass::cast(abk)->is_shared_boot_class(),
662 "must be boot class");
663 check_allowed_klass(InstanceKlass::cast(ObjArrayKlass::cast(orig_k)->bottom_klass()));
664 }
665 if (buffered_k == Universe::objectArrayKlassObj()) {
666 // Initialized early during Universe::genesis. No need to be added
667 // to the list.
668 return;
669 }
670 } else {
671 assert(buffered_k->is_typeArray_klass(), "must be");
672 // Primitive type arrays are created early during Universe::genesis.
673 return;
674 }
675
676 if (log_is_enabled(Debug, cds, heap)) {
677 if (!_subgraph_object_klasses->contains(buffered_k)) {
678 ResourceMark rm;
679 log_debug(cds, heap)("Adding klass %s", orig_k->external_name());
680 }
681 }
682
683 _subgraph_object_klasses->append_if_missing(buffered_k);
684 _has_non_early_klasses |= is_non_early_klass(orig_k);
685 }
686
687 void KlassSubGraphInfo::check_allowed_klass(InstanceKlass* ik) {
688 if (ik->module()->name() == vmSymbols::java_base()) {
689 assert(ik->package() != nullptr, "classes in java.base cannot be in unnamed package");
690 return;
691 }
692
693 #ifndef PRODUCT
694 if (!ik->module()->is_named() && ik->package() == nullptr) {
695 // This class is loaded by ArchiveHeapTestClass
696 return;
697 }
698 const char* extra_msg = ", or in an unnamed package of an unnamed module";
699 #else
700 const char* extra_msg = "";
701 #endif
702
703 ResourceMark rm;
704 log_error(cds, heap)("Class %s not allowed in archive heap. Must be in java.base%s",
705 ik->external_name(), extra_msg);
706 MetaspaceShared::unrecoverable_writing_error();
707 }
708
709 bool KlassSubGraphInfo::is_non_early_klass(Klass* k) {
710 if (k->is_objArray_klass()) {
711 k = ObjArrayKlass::cast(k)->bottom_klass();
712 }
713 if (k->is_instance_klass()) {
714 if (!SystemDictionaryShared::is_early_klass(InstanceKlass::cast(k))) {
715 ResourceMark rm;
716 log_info(cds, heap)("non-early: %s", k->external_name());
717 return true;
718 } else {
719 return false;
720 }
721 } else {
722 return false;
723 }
724 }
725
726 // Initialize an archived subgraph_info_record from the given KlassSubGraphInfo.
727 void ArchivedKlassSubGraphInfoRecord::init(KlassSubGraphInfo* info) {
728 _k = info->klass();
729 _entry_field_records = nullptr;
730 _subgraph_object_klasses = nullptr;
731 _is_full_module_graph = info->is_full_module_graph();
732
733 if (_is_full_module_graph) {
734 // Consider all classes referenced by the full module graph as early -- we will be
735 // allocating objects of these classes during JVMTI early phase, so they cannot
736 // be processed by (non-early) JVMTI ClassFileLoadHook
737 _has_non_early_klasses = false;
738 } else {
739 _has_non_early_klasses = info->has_non_early_klasses();
740 }
741
742 if (_has_non_early_klasses) {
743 ResourceMark rm;
744 log_info(cds, heap)(
745 "Subgraph of klass %s has non-early klasses and cannot be used when JVMTI ClassFileLoadHook is enabled",
746 _k->external_name());
747 }
748
749 // populate the entry fields
750 GrowableArray<int>* entry_fields = info->subgraph_entry_fields();
751 if (entry_fields != nullptr) {
752 int num_entry_fields = entry_fields->length();
753 assert(num_entry_fields % 2 == 0, "sanity");
754 _entry_field_records =
755 ArchiveBuilder::new_ro_array<int>(num_entry_fields);
756 for (int i = 0 ; i < num_entry_fields; i++) {
757 _entry_field_records->at_put(i, entry_fields->at(i));
758 }
759 }
760
761 // the Klasses of the objects in the sub-graphs
762 GrowableArray<Klass*>* subgraph_object_klasses = info->subgraph_object_klasses();
763 if (subgraph_object_klasses != nullptr) {
764 int num_subgraphs_klasses = subgraph_object_klasses->length();
765 _subgraph_object_klasses =
766 ArchiveBuilder::new_ro_array<Klass*>(num_subgraphs_klasses);
767 for (int i = 0; i < num_subgraphs_klasses; i++) {
768 Klass* subgraph_k = subgraph_object_klasses->at(i);
769 if (log_is_enabled(Info, cds, heap)) {
770 ResourceMark rm;
771 log_info(cds, heap)(
772 "Archived object klass %s (%2d) => %s",
773 _k->external_name(), i, subgraph_k->external_name());
774 }
775 _subgraph_object_klasses->at_put(i, subgraph_k);
776 ArchivePtrMarker::mark_pointer(_subgraph_object_klasses->adr_at(i));
777 }
778 }
779
780 ArchivePtrMarker::mark_pointer(&_k);
781 ArchivePtrMarker::mark_pointer(&_entry_field_records);
782 ArchivePtrMarker::mark_pointer(&_subgraph_object_klasses);
783 }
784
785 struct CopyKlassSubGraphInfoToArchive : StackObj {
786 CompactHashtableWriter* _writer;
787 CopyKlassSubGraphInfoToArchive(CompactHashtableWriter* writer) : _writer(writer) {}
788
789 bool do_entry(Klass* klass, KlassSubGraphInfo& info) {
790 if (info.subgraph_object_klasses() != nullptr || info.subgraph_entry_fields() != nullptr) {
791 ArchivedKlassSubGraphInfoRecord* record =
792 (ArchivedKlassSubGraphInfoRecord*)ArchiveBuilder::ro_region_alloc(sizeof(ArchivedKlassSubGraphInfoRecord));
793 record->init(&info);
794
795 Klass* buffered_k = ArchiveBuilder::get_buffered_klass(klass);
796 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary((address)buffered_k);
797 u4 delta = ArchiveBuilder::current()->any_to_offset_u4(record);
798 _writer->add(hash, delta);
799 }
800 return true; // keep on iterating
801 }
802 };
803
804 // Build the records of archived subgraph infos, which include:
805 // - Entry points to all subgraphs from the containing class mirror. The entry
806 // points are static fields in the mirror. For each entry point, the field
807 // offset, and value are recorded in the sub-graph
808 // info. The value is stored back to the corresponding field at runtime.
809 // - A list of klasses that need to be loaded/initialized before archived
810 // java object sub-graph can be accessed at runtime.
811 void HeapShared::write_subgraph_info_table() {
812 // Allocate the contents of the hashtable(s) inside the RO region of the CDS archive.
813 DumpTimeKlassSubGraphInfoTable* d_table = _dump_time_subgraph_info_table;
814 CompactHashtableStats stats;
815
816 _run_time_subgraph_info_table.reset();
817
818 CompactHashtableWriter writer(d_table->_count, &stats);
819 CopyKlassSubGraphInfoToArchive copy(&writer);
820 d_table->iterate(©);
821 writer.dump(&_run_time_subgraph_info_table, "subgraphs");
822
823 #ifndef PRODUCT
824 if (ArchiveHeapTestClass != nullptr) {
825 size_t len = strlen(ArchiveHeapTestClass) + 1;
826 Array<char>* array = ArchiveBuilder::new_ro_array<char>((int)len);
827 strncpy(array->adr_at(0), ArchiveHeapTestClass, len);
828 _archived_ArchiveHeapTestClass = array;
829 }
830 #endif
831 if (log_is_enabled(Info, cds, heap)) {
832 print_stats();
833 }
834 }
835
836 void HeapShared::serialize_root(SerializeClosure* soc) {
837 oop roots_oop = nullptr;
838
839 if (soc->reading()) {
840 soc->do_oop(&roots_oop); // read from archive
841 assert(oopDesc::is_oop_or_null(roots_oop), "is oop");
842 // Create an OopHandle only if we have actually mapped or loaded the roots
843 if (roots_oop != nullptr) {
844 assert(ArchiveHeapLoader::is_in_use(), "must be");
845 _roots = OopHandle(Universe::vm_global(), roots_oop);
846 }
847 } else {
848 // writing
849 if (HeapShared::can_write()) {
850 roots_oop = ArchiveHeapWriter::heap_roots_requested_address();
851 }
852 soc->do_oop(&roots_oop); // write to archive
853 }
854 }
855
856 void HeapShared::serialize_tables(SerializeClosure* soc) {
857
858 #ifndef PRODUCT
859 soc->do_ptr((void**)&_archived_ArchiveHeapTestClass);
860 if (soc->reading() && _archived_ArchiveHeapTestClass != nullptr) {
861 _test_class_name = _archived_ArchiveHeapTestClass->adr_at(0);
862 setup_test_class(_test_class_name);
863 }
864 #endif
865
866 _run_time_subgraph_info_table.serialize_header(soc);
867 }
868
869 static void verify_the_heap(Klass* k, const char* which) {
870 if (VerifyArchivedFields > 0) {
871 ResourceMark rm;
872 log_info(cds, heap)("Verify heap %s initializing static field(s) in %s",
873 which, k->external_name());
874
875 VM_Verify verify_op;
876 VMThread::execute(&verify_op);
877
878 if (VerifyArchivedFields > 1 && is_init_completed()) {
879 // At this time, the oop->klass() of some archived objects in the heap may not
880 // have been loaded into the system dictionary yet. Nevertheless, oop->klass() should
881 // have enough information (object size, oop maps, etc) so that a GC can be safely
882 // performed.
883 //
884 // -XX:VerifyArchivedFields=2 force a GC to happen in such an early stage
885 // to check for GC safety.
886 log_info(cds, heap)("Trigger GC %s initializing static field(s) in %s",
887 which, k->external_name());
888 FlagSetting fs1(VerifyBeforeGC, true);
889 FlagSetting fs2(VerifyDuringGC, true);
890 FlagSetting fs3(VerifyAfterGC, true);
891 Universe::heap()->collect(GCCause::_java_lang_system_gc);
892 }
893 }
894 }
895
896 // Before GC can execute, we must ensure that all oops reachable from HeapShared::roots()
897 // have a valid klass. I.e., oopDesc::klass() must have already been resolved.
898 //
899 // Note: if a ArchivedKlassSubGraphInfoRecord contains non-early classes, and JVMTI
900 // ClassFileLoadHook is enabled, it's possible for this class to be dynamically replaced. In
901 // this case, we will not load the ArchivedKlassSubGraphInfoRecord and will clear its roots.
902 void HeapShared::resolve_classes(JavaThread* current) {
903 assert(UseSharedSpaces, "runtime only!");
904 if (!ArchiveHeapLoader::is_in_use()) {
905 return; // nothing to do
906 }
907 resolve_classes_for_subgraphs(current, archive_subgraph_entry_fields);
908 resolve_classes_for_subgraphs(current, fmg_archive_subgraph_entry_fields);
909 }
910
911 void HeapShared::resolve_classes_for_subgraphs(JavaThread* current, ArchivableStaticFieldInfo fields[]) {
912 for (int i = 0; fields[i].valid(); i++) {
913 ArchivableStaticFieldInfo* info = &fields[i];
914 TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name);
915 InstanceKlass* k = SystemDictionaryShared::find_builtin_class(klass_name);
916 assert(k != nullptr && k->is_shared_boot_class(), "sanity");
917 resolve_classes_for_subgraph_of(current, k);
918 }
919 }
920
921 void HeapShared::resolve_classes_for_subgraph_of(JavaThread* current, Klass* k) {
922 JavaThread* THREAD = current;
923 ExceptionMark em(THREAD);
924 const ArchivedKlassSubGraphInfoRecord* record =
925 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/false, THREAD);
926 if (HAS_PENDING_EXCEPTION) {
927 CLEAR_PENDING_EXCEPTION;
928 }
929 if (record == nullptr) {
930 clear_archived_roots_of(k);
931 }
932 }
933
934 void HeapShared::initialize_from_archived_subgraph(JavaThread* current, Klass* k) {
935 JavaThread* THREAD = current;
936 if (!ArchiveHeapLoader::is_in_use()) {
937 return; // nothing to do
938 }
939
940 ExceptionMark em(THREAD);
941 const ArchivedKlassSubGraphInfoRecord* record =
942 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/true, THREAD);
943
944 if (HAS_PENDING_EXCEPTION) {
945 CLEAR_PENDING_EXCEPTION;
946 // None of the field value will be set if there was an exception when initializing the classes.
947 // The java code will not see any of the archived objects in the
948 // subgraphs referenced from k in this case.
949 return;
950 }
951
952 if (record != nullptr) {
953 init_archived_fields_for(k, record);
954 }
955 }
956
957 const ArchivedKlassSubGraphInfoRecord*
958 HeapShared::resolve_or_init_classes_for_subgraph_of(Klass* k, bool do_init, TRAPS) {
959 assert(!DumpSharedSpaces, "Should not be called with DumpSharedSpaces");
960
961 if (!k->is_shared()) {
962 return nullptr;
963 }
964 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary_quick(k);
965 const ArchivedKlassSubGraphInfoRecord* record = _run_time_subgraph_info_table.lookup(k, hash, 0);
966
967 #ifndef PRODUCT
968 if (_test_class_name != nullptr && k->name()->equals(_test_class_name) && record != nullptr) {
969 _test_class = k;
970 _test_class_record = record;
971 }
972 #endif
973
974 // Initialize from archived data. Currently this is done only
975 // during VM initialization time. No lock is needed.
976 if (record != nullptr) {
977 if (record->is_full_module_graph() && !MetaspaceShared::use_full_module_graph()) {
978 if (log_is_enabled(Info, cds, heap)) {
979 ResourceMark rm(THREAD);
980 log_info(cds, heap)("subgraph %s cannot be used because full module graph is disabled",
981 k->external_name());
982 }
983 return nullptr;
984 }
985
986 if (record->has_non_early_klasses() && JvmtiExport::should_post_class_file_load_hook()) {
987 if (log_is_enabled(Info, cds, heap)) {
988 ResourceMark rm(THREAD);
989 log_info(cds, heap)("subgraph %s cannot be used because JVMTI ClassFileLoadHook is enabled",
990 k->external_name());
991 }
992 return nullptr;
993 }
994
995 if (log_is_enabled(Info, cds, heap)) {
996 ResourceMark rm;
997 log_info(cds, heap)("%s subgraph %s ", do_init ? "init" : "resolve", k->external_name());
998 }
999
1000 resolve_or_init(k, do_init, CHECK_NULL);
1001
1002 // Load/link/initialize the klasses of the objects in the subgraph.
1003 // nullptr class loader is used.
1004 Array<Klass*>* klasses = record->subgraph_object_klasses();
1005 if (klasses != nullptr) {
1006 for (int i = 0; i < klasses->length(); i++) {
1007 Klass* klass = klasses->at(i);
1008 if (!klass->is_shared()) {
1009 return nullptr;
1010 }
1011 resolve_or_init(klass, do_init, CHECK_NULL);
1012 }
1013 }
1014 }
1015
1016 return record;
1017 }
1018
1019 void HeapShared::resolve_or_init(Klass* k, bool do_init, TRAPS) {
1020 if (!do_init) {
1021 if (k->class_loader_data() == nullptr) {
1022 Klass* resolved_k = SystemDictionary::resolve_or_null(k->name(), CHECK);
1023 assert(resolved_k == k, "classes used by archived heap must not be replaced by JVMTI ClassFileLoadHook");
1024 }
1025 } else {
1026 assert(k->class_loader_data() != nullptr, "must have been resolved by HeapShared::resolve_classes");
1027 if (k->is_instance_klass()) {
1028 InstanceKlass* ik = InstanceKlass::cast(k);
1029 ik->initialize(CHECK);
1030 } else if (k->is_objArray_klass()) {
1031 ObjArrayKlass* oak = ObjArrayKlass::cast(k);
1032 oak->initialize(CHECK);
1033 }
1034 }
1035 }
1036
1037 void HeapShared::init_archived_fields_for(Klass* k, const ArchivedKlassSubGraphInfoRecord* record) {
1038 verify_the_heap(k, "before");
1039
1040 // Load the subgraph entry fields from the record and store them back to
1041 // the corresponding fields within the mirror.
1042 oop m = k->java_mirror();
1043 Array<int>* entry_field_records = record->entry_field_records();
1044 if (entry_field_records != nullptr) {
1045 int efr_len = entry_field_records->length();
1046 assert(efr_len % 2 == 0, "sanity");
1047 for (int i = 0; i < efr_len; i += 2) {
1048 int field_offset = entry_field_records->at(i);
1049 int root_index = entry_field_records->at(i+1);
1050 oop v = get_root(root_index, /*clear=*/true);
1051 m->obj_field_put(field_offset, v);
1052 log_debug(cds, heap)(" " PTR_FORMAT " init field @ %2d = " PTR_FORMAT, p2i(k), field_offset, p2i(v));
1053 }
1054
1055 // Done. Java code can see the archived sub-graphs referenced from k's
1056 // mirror after this point.
1057 if (log_is_enabled(Info, cds, heap)) {
1058 ResourceMark rm;
1059 log_info(cds, heap)("initialize_from_archived_subgraph %s " PTR_FORMAT "%s",
1060 k->external_name(), p2i(k), JvmtiExport::is_early_phase() ? " (early)" : "");
1061 }
1062 }
1063
1064 verify_the_heap(k, "after ");
1065 }
1066
1067 void HeapShared::clear_archived_roots_of(Klass* k) {
1068 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary_quick(k);
1069 const ArchivedKlassSubGraphInfoRecord* record = _run_time_subgraph_info_table.lookup(k, hash, 0);
1070 if (record != nullptr) {
1071 Array<int>* entry_field_records = record->entry_field_records();
1072 if (entry_field_records != nullptr) {
1073 int efr_len = entry_field_records->length();
1074 assert(efr_len % 2 == 0, "sanity");
1075 for (int i = 0; i < efr_len; i += 2) {
1076 int root_index = entry_field_records->at(i+1);
1077 clear_root(root_index);
1078 }
1079 }
1080 }
1081 }
1082
1083 class WalkOopAndArchiveClosure: public BasicOopIterateClosure {
1084 int _level;
1085 bool _record_klasses_only;
1086 KlassSubGraphInfo* _subgraph_info;
1087 oop _referencing_obj;
1088
1089 // The following are for maintaining a stack for determining
1090 // CachedOopInfo::_referrer
1091 static WalkOopAndArchiveClosure* _current;
1092 WalkOopAndArchiveClosure* _last;
1093 public:
1094 WalkOopAndArchiveClosure(int level,
1095 bool record_klasses_only,
1096 KlassSubGraphInfo* subgraph_info,
1097 oop orig) :
1098 _level(level),
1099 _record_klasses_only(record_klasses_only),
1100 _subgraph_info(subgraph_info),
1101 _referencing_obj(orig) {
1102 _last = _current;
1103 _current = this;
1104 }
1105 ~WalkOopAndArchiveClosure() {
1106 _current = _last;
1107 }
1108 void do_oop(narrowOop *p) { WalkOopAndArchiveClosure::do_oop_work(p); }
1109 void do_oop( oop *p) { WalkOopAndArchiveClosure::do_oop_work(p); }
1110
1111 protected:
1112 template <class T> void do_oop_work(T *p) {
1113 oop obj = RawAccess<>::oop_load(p);
1114 if (!CompressedOops::is_null(obj)) {
1115 size_t field_delta = pointer_delta(p, _referencing_obj, sizeof(char));
1116
1117 if (!_record_klasses_only && log_is_enabled(Debug, cds, heap)) {
1118 ResourceMark rm;
1119 log_debug(cds, heap)("(%d) %s[" SIZE_FORMAT "] ==> " PTR_FORMAT " size " SIZE_FORMAT " %s", _level,
1120 _referencing_obj->klass()->external_name(), field_delta,
1121 p2i(obj), obj->size() * HeapWordSize, obj->klass()->external_name());
1122 if (log_is_enabled(Trace, cds, heap)) {
1123 LogTarget(Trace, cds, heap) log;
1124 LogStream out(log);
1125 obj->print_on(&out);
1126 }
1127 }
1128
1129 bool success = HeapShared::archive_reachable_objects_from(
1130 _level + 1, _subgraph_info, obj);
1131 assert(success, "VM should have exited with unarchivable objects for _level > 1");
1132 }
1133 }
1134
1135 public:
1136 static WalkOopAndArchiveClosure* current() { return _current; }
1137 oop referencing_obj() { return _referencing_obj; }
1138 KlassSubGraphInfo* subgraph_info() { return _subgraph_info; }
1139 };
1140
1141 WalkOopAndArchiveClosure* WalkOopAndArchiveClosure::_current = nullptr;
1142
1143 HeapShared::CachedOopInfo HeapShared::make_cached_oop_info() {
1144 WalkOopAndArchiveClosure* walker = WalkOopAndArchiveClosure::current();
1145 oop referrer = (walker == nullptr) ? nullptr : walker->referencing_obj();
1146 return CachedOopInfo(referrer);
1147 }
1148
1149 // (1) If orig_obj has not been archived yet, archive it.
1150 // (2) If orig_obj has not been seen yet (since start_recording_subgraph() was called),
1151 // trace all objects that are reachable from it, and make sure these objects are archived.
1152 // (3) Record the klasses of all orig_obj and all reachable objects.
1153 bool HeapShared::archive_reachable_objects_from(int level,
1154 KlassSubGraphInfo* subgraph_info,
1155 oop orig_obj) {
1156 assert(orig_obj != nullptr, "must be");
1157
1158 if (!JavaClasses::is_supported_for_archiving(orig_obj)) {
1159 // This object has injected fields that cannot be supported easily, so we disallow them for now.
1160 // If you get an error here, you probably made a change in the JDK library that has added
1161 // these objects that are referenced (directly or indirectly) by static fields.
1162 ResourceMark rm;
1163 log_error(cds, heap)("Cannot archive object of class %s", orig_obj->klass()->external_name());
1164 MetaspaceShared::unrecoverable_writing_error();
1165 }
1166
1167 // java.lang.Class instances cannot be included in an archived object sub-graph. We only support
1168 // them as Klass::_archived_mirror because they need to be specially restored at run time.
1169 //
1170 // If you get an error here, you probably made a change in the JDK library that has added a Class
1171 // object that is referenced (directly or indirectly) by static fields.
1172 if (java_lang_Class::is_instance(orig_obj) && subgraph_info != _default_subgraph_info) {
1173 log_error(cds, heap)("(%d) Unknown java.lang.Class object is in the archived sub-graph", level);
1174 MetaspaceShared::unrecoverable_writing_error();
1175 }
1176
1177 if (has_been_seen_during_subgraph_recording(orig_obj)) {
1178 // orig_obj has already been archived and traced. Nothing more to do.
1179 return true;
1180 } else {
1181 set_has_been_seen_during_subgraph_recording(orig_obj);
1182 }
1183
1184 bool already_archived = has_been_archived(orig_obj);
1185 bool record_klasses_only = already_archived;
1186 if (!already_archived) {
1187 ++_num_new_archived_objs;
1188 if (!archive_object(orig_obj)) {
1189 // Skip archiving the sub-graph referenced from the current entry field.
1190 ResourceMark rm;
1191 log_error(cds, heap)(
1192 "Cannot archive the sub-graph referenced from %s object ("
1193 PTR_FORMAT ") size " SIZE_FORMAT ", skipped.",
1194 orig_obj->klass()->external_name(), p2i(orig_obj), orig_obj->size() * HeapWordSize);
1195 if (level == 1) {
1196 // Don't archive a subgraph root that's too big. For archives static fields, that's OK
1197 // as the Java code will take care of initializing this field dynamically.
1198 return false;
1199 } else {
1200 // We don't know how to handle an object that has been archived, but some of its reachable
1201 // objects cannot be archived. Bail out for now. We might need to fix this in the future if
1202 // we have a real use case.
1203 MetaspaceShared::unrecoverable_writing_error();
1204 }
1205 }
1206 }
1207
1208 Klass *orig_k = orig_obj->klass();
1209 subgraph_info->add_subgraph_object_klass(orig_k);
1210
1211 WalkOopAndArchiveClosure walker(level, record_klasses_only, subgraph_info, orig_obj);
1212 orig_obj->oop_iterate(&walker);
1213
1214 check_enum_obj(level + 1, subgraph_info, orig_obj);
1215 return true;
1216 }
1217
1218 //
1219 // Start from the given static field in a java mirror and archive the
1220 // complete sub-graph of java heap objects that are reached directly
1221 // or indirectly from the starting object by following references.
1222 // Sub-graph archiving restrictions (current):
1223 //
1224 // - All classes of objects in the archived sub-graph (including the
1225 // entry class) must be boot class only.
1226 // - No java.lang.Class instance (java mirror) can be included inside
1227 // an archived sub-graph. Mirror can only be the sub-graph entry object.
1228 //
1229 // The Java heap object sub-graph archiving process (see
1230 // WalkOopAndArchiveClosure):
1231 //
1232 // 1) Java object sub-graph archiving starts from a given static field
1233 // within a Class instance (java mirror). If the static field is a
1234 // reference field and points to a non-null java object, proceed to
1235 // the next step.
1236 //
1237 // 2) Archives the referenced java object. If an archived copy of the
1238 // current object already exists, updates the pointer in the archived
1239 // copy of the referencing object to point to the current archived object.
1240 // Otherwise, proceed to the next step.
1241 //
1242 // 3) Follows all references within the current java object and recursively
1243 // archive the sub-graph of objects starting from each reference.
1244 //
1245 // 4) Updates the pointer in the archived copy of referencing object to
1246 // point to the current archived object.
1247 //
1248 // 5) The Klass of the current java object is added to the list of Klasses
1249 // for loading and initializing before any object in the archived graph can
1250 // be accessed at runtime.
1251 //
1252 void HeapShared::archive_reachable_objects_from_static_field(InstanceKlass *k,
1253 const char* klass_name,
1254 int field_offset,
1255 const char* field_name) {
1256 assert(DumpSharedSpaces, "dump time only");
1257 assert(k->is_shared_boot_class(), "must be boot class");
1258
1259 oop m = k->java_mirror();
1260
1261 KlassSubGraphInfo* subgraph_info = get_subgraph_info(k);
1262 oop f = m->obj_field(field_offset);
1263
1264 log_debug(cds, heap)("Start archiving from: %s::%s (" PTR_FORMAT ")", klass_name, field_name, p2i(f));
1265
1266 if (!CompressedOops::is_null(f)) {
1267 if (log_is_enabled(Trace, cds, heap)) {
1268 LogTarget(Trace, cds, heap) log;
1269 LogStream out(log);
1270 f->print_on(&out);
1271 }
1272
1273 bool success = archive_reachable_objects_from(1, subgraph_info, f);
1274 if (!success) {
1275 log_error(cds, heap)("Archiving failed %s::%s (some reachable objects cannot be archived)",
1276 klass_name, field_name);
1277 } else {
1278 // Note: the field value is not preserved in the archived mirror.
1279 // Record the field as a new subGraph entry point. The recorded
1280 // information is restored from the archive at runtime.
1281 subgraph_info->add_subgraph_entry_field(field_offset, f);
1282 log_info(cds, heap)("Archived field %s::%s => " PTR_FORMAT, klass_name, field_name, p2i(f));
1283 }
1284 } else {
1285 // The field contains null, we still need to record the entry point,
1286 // so it can be restored at runtime.
1287 subgraph_info->add_subgraph_entry_field(field_offset, nullptr);
1288 }
1289 }
1290
1291 #ifndef PRODUCT
1292 class VerifySharedOopClosure: public BasicOopIterateClosure {
1293 public:
1294 void do_oop(narrowOop *p) { VerifySharedOopClosure::do_oop_work(p); }
1295 void do_oop( oop *p) { VerifySharedOopClosure::do_oop_work(p); }
1296
1297 protected:
1298 template <class T> void do_oop_work(T *p) {
1299 oop obj = RawAccess<>::oop_load(p);
1300 if (!CompressedOops::is_null(obj)) {
1301 HeapShared::verify_reachable_objects_from(obj);
1302 }
1303 }
1304 };
1305
1306 void HeapShared::verify_subgraph_from_static_field(InstanceKlass* k, int field_offset) {
1307 assert(DumpSharedSpaces, "dump time only");
1308 assert(k->is_shared_boot_class(), "must be boot class");
1309
1310 oop m = k->java_mirror();
1311 oop f = m->obj_field(field_offset);
1312 if (!CompressedOops::is_null(f)) {
1313 verify_subgraph_from(f);
1314 }
1315 }
1316
1317 void HeapShared::verify_subgraph_from(oop orig_obj) {
1318 if (!has_been_archived(orig_obj)) {
1319 // It's OK for the root of a subgraph to be not archived. See comments in
1320 // archive_reachable_objects_from().
1321 return;
1322 }
1323
1324 // Verify that all objects reachable from orig_obj are archived.
1325 init_seen_objects_table();
1326 verify_reachable_objects_from(orig_obj);
1327 delete_seen_objects_table();
1328 }
1329
1330 void HeapShared::verify_reachable_objects_from(oop obj) {
1331 _num_total_verifications ++;
1332 if (!has_been_seen_during_subgraph_recording(obj)) {
1333 set_has_been_seen_during_subgraph_recording(obj);
1334 assert(has_been_archived(obj), "must be");
1335 VerifySharedOopClosure walker;
1336 obj->oop_iterate(&walker);
1337 }
1338 }
1339 #endif
1340
1341 // The "default subgraph" contains special objects (see heapShared.hpp) that
1342 // can be accessed before we load any Java classes (including java/lang/Class).
1343 // Make sure that these are only instances of the very few specific types
1344 // that we can handle.
1345 void HeapShared::check_default_subgraph_classes() {
1346 GrowableArray<Klass*>* klasses = _default_subgraph_info->subgraph_object_klasses();
1347 int num = klasses->length();
1348 for (int i = 0; i < num; i++) {
1349 Klass* subgraph_k = klasses->at(i);
1350 if (log_is_enabled(Info, cds, heap)) {
1351 ResourceMark rm;
1352 log_info(cds, heap)(
1353 "Archived object klass (default subgraph %d) => %s",
1354 i, subgraph_k->external_name());
1355 }
1356
1357 guarantee(subgraph_k->name()->equals("java/lang/Class") ||
1358 subgraph_k->name()->equals("java/lang/String") ||
1359 subgraph_k->name()->equals("[Ljava/lang/Object;") ||
1360 subgraph_k->name()->equals("[C") ||
1361 subgraph_k->name()->equals("[B"),
1362 "default subgraph can have only these objects");
1363 }
1364 }
1365
1366 HeapShared::SeenObjectsTable* HeapShared::_seen_objects_table = nullptr;
1367 int HeapShared::_num_new_walked_objs;
1368 int HeapShared::_num_new_archived_objs;
1369 int HeapShared::_num_old_recorded_klasses;
1370
1371 int HeapShared::_num_total_subgraph_recordings = 0;
1372 int HeapShared::_num_total_walked_objs = 0;
1373 int HeapShared::_num_total_archived_objs = 0;
1374 int HeapShared::_num_total_recorded_klasses = 0;
1375 int HeapShared::_num_total_verifications = 0;
1376
1377 bool HeapShared::has_been_seen_during_subgraph_recording(oop obj) {
1378 return _seen_objects_table->get(obj) != nullptr;
1379 }
1380
1381 void HeapShared::set_has_been_seen_during_subgraph_recording(oop obj) {
1382 assert(!has_been_seen_during_subgraph_recording(obj), "sanity");
1383 _seen_objects_table->put(obj, true);
1384 ++ _num_new_walked_objs;
1385 }
1386
1387 void HeapShared::start_recording_subgraph(InstanceKlass *k, const char* class_name, bool is_full_module_graph) {
1388 log_info(cds, heap)("Start recording subgraph(s) for archived fields in %s", class_name);
1389 init_subgraph_info(k, is_full_module_graph);
1390 init_seen_objects_table();
1391 _num_new_walked_objs = 0;
1392 _num_new_archived_objs = 0;
1393 _num_old_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses();
1394 }
1395
1396 void HeapShared::done_recording_subgraph(InstanceKlass *k, const char* class_name) {
1397 int num_new_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses() -
1398 _num_old_recorded_klasses;
1399 log_info(cds, heap)("Done recording subgraph(s) for archived fields in %s: "
1400 "walked %d objs, archived %d new objs, recorded %d classes",
1401 class_name, _num_new_walked_objs, _num_new_archived_objs,
1402 num_new_recorded_klasses);
1403
1404 delete_seen_objects_table();
1405
1406 _num_total_subgraph_recordings ++;
1407 _num_total_walked_objs += _num_new_walked_objs;
1408 _num_total_archived_objs += _num_new_archived_objs;
1409 _num_total_recorded_klasses += num_new_recorded_klasses;
1410 }
1411
1412 class ArchivableStaticFieldFinder: public FieldClosure {
1413 InstanceKlass* _ik;
1414 Symbol* _field_name;
1415 bool _found;
1416 int _offset;
1417 public:
1418 ArchivableStaticFieldFinder(InstanceKlass* ik, Symbol* field_name) :
1419 _ik(ik), _field_name(field_name), _found(false), _offset(-1) {}
1420
1421 virtual void do_field(fieldDescriptor* fd) {
1422 if (fd->name() == _field_name) {
1423 assert(!_found, "fields can never be overloaded");
1424 if (is_reference_type(fd->field_type())) {
1425 _found = true;
1426 _offset = fd->offset();
1427 }
1428 }
1429 }
1430 bool found() { return _found; }
1431 int offset() { return _offset; }
1432 };
1433
1434 void HeapShared::init_subgraph_entry_fields(ArchivableStaticFieldInfo fields[],
1435 TRAPS) {
1436 for (int i = 0; fields[i].valid(); i++) {
1437 ArchivableStaticFieldInfo* info = &fields[i];
1438 TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name);
1439 TempNewSymbol field_name = SymbolTable::new_symbol(info->field_name);
1440 ResourceMark rm; // for stringStream::as_string() etc.
1441
1442 #ifndef PRODUCT
1443 bool is_test_class = (ArchiveHeapTestClass != nullptr) && (strcmp(info->klass_name, ArchiveHeapTestClass) == 0);
1444 #else
1445 bool is_test_class = false;
1446 #endif
1447
1448 if (is_test_class) {
1449 log_warning(cds)("Loading ArchiveHeapTestClass %s ...", ArchiveHeapTestClass);
1450 }
1451
1452 Klass* k = SystemDictionary::resolve_or_fail(klass_name, true, THREAD);
1453 if (HAS_PENDING_EXCEPTION) {
1454 CLEAR_PENDING_EXCEPTION;
1455 stringStream st;
1456 st.print("Fail to initialize archive heap: %s cannot be loaded by the boot loader", info->klass_name);
1457 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
1458 }
1459
1460 if (!k->is_instance_klass()) {
1461 stringStream st;
1462 st.print("Fail to initialize archive heap: %s is not an instance class", info->klass_name);
1463 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
1464 }
1465
1466 InstanceKlass* ik = InstanceKlass::cast(k);
1467 assert(InstanceKlass::cast(ik)->is_shared_boot_class(),
1468 "Only support boot classes");
1469
1470 if (is_test_class) {
1471 if (ik->module()->is_named()) {
1472 // We don't want ArchiveHeapTestClass to be abused to easily load/initialize arbitrary
1473 // core-lib classes. You need to at least append to the bootclasspath.
1474 stringStream st;
1475 st.print("ArchiveHeapTestClass %s is not in unnamed module", ArchiveHeapTestClass);
1476 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
1477 }
1478
1479 if (ik->package() != nullptr) {
1480 // This restriction makes HeapShared::is_a_test_class_in_unnamed_module() easy.
1481 stringStream st;
1482 st.print("ArchiveHeapTestClass %s is not in unnamed package", ArchiveHeapTestClass);
1483 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
1484 }
1485 } else {
1486 if (ik->module()->name() != vmSymbols::java_base()) {
1487 // We don't want to deal with cases when a module is unavailable at runtime.
1488 // FUTURE -- load from archived heap only when module graph has not changed
1489 // between dump and runtime.
1490 stringStream st;
1491 st.print("%s is not in java.base module", info->klass_name);
1492 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
1493 }
1494 }
1495
1496 if (is_test_class) {
1497 log_warning(cds)("Initializing ArchiveHeapTestClass %s ...", ArchiveHeapTestClass);
1498 }
1499 ik->initialize(CHECK);
1500
1501 ArchivableStaticFieldFinder finder(ik, field_name);
1502 ik->do_local_static_fields(&finder);
1503 if (!finder.found()) {
1504 stringStream st;
1505 st.print("Unable to find the static T_OBJECT field %s::%s", info->klass_name, info->field_name);
1506 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
1507 }
1508
1509 info->klass = ik;
1510 info->offset = finder.offset();
1511 }
1512 }
1513
1514 void HeapShared::init_subgraph_entry_fields(TRAPS) {
1515 assert(HeapShared::can_write(), "must be");
1516 _dump_time_subgraph_info_table = new (mtClass)DumpTimeKlassSubGraphInfoTable();
1517 init_subgraph_entry_fields(archive_subgraph_entry_fields, CHECK);
1518 if (MetaspaceShared::use_full_module_graph()) {
1519 init_subgraph_entry_fields(fmg_archive_subgraph_entry_fields, CHECK);
1520 }
1521 }
1522
1523 #ifndef PRODUCT
1524 void HeapShared::setup_test_class(const char* test_class_name) {
1525 ArchivableStaticFieldInfo* p = archive_subgraph_entry_fields;
1526 int num_slots = sizeof(archive_subgraph_entry_fields) / sizeof(ArchivableStaticFieldInfo);
1527 assert(p[num_slots - 2].klass_name == nullptr, "must have empty slot that's patched below");
1528 assert(p[num_slots - 1].klass_name == nullptr, "must have empty slot that marks the end of the list");
1529
1530 if (test_class_name != nullptr) {
1531 p[num_slots - 2].klass_name = test_class_name;
1532 p[num_slots - 2].field_name = ARCHIVE_TEST_FIELD_NAME;
1533 }
1534 }
1535
1536 // See if ik is one of the test classes that are pulled in by -XX:ArchiveHeapTestClass
1537 // during runtime. This may be called before the module system is initialized so
1538 // we cannot rely on InstanceKlass::module(), etc.
1539 bool HeapShared::is_a_test_class_in_unnamed_module(Klass* ik) {
1540 if (_test_class != nullptr) {
1541 if (ik == _test_class) {
1542 return true;
1543 }
1544 Array<Klass*>* klasses = _test_class_record->subgraph_object_klasses();
1545 if (klasses == nullptr) {
1546 return false;
1547 }
1548
1549 for (int i = 0; i < klasses->length(); i++) {
1550 Klass* k = klasses->at(i);
1551 if (k == ik) {
1552 Symbol* name;
1553 if (k->is_instance_klass()) {
1554 name = InstanceKlass::cast(k)->name();
1555 } else if (k->is_objArray_klass()) {
1556 Klass* bk = ObjArrayKlass::cast(k)->bottom_klass();
1557 if (!bk->is_instance_klass()) {
1558 return false;
1559 }
1560 name = bk->name();
1561 } else {
1562 return false;
1563 }
1564
1565 // See KlassSubGraphInfo::check_allowed_klass() - only two types of
1566 // classes are allowed:
1567 // (A) java.base classes (which must not be in the unnamed module)
1568 // (B) test classes which must be in the unnamed package of the unnamed module.
1569 // So if we see a '/' character in the class name, it must be in (A);
1570 // otherwise it must be in (B).
1571 if (name->index_of_at(0, "/", 1) >= 0) {
1572 return false; // (A)
1573 }
1574
1575 return true; // (B)
1576 }
1577 }
1578 }
1579
1580 return false;
1581 }
1582 #endif
1583
1584 void HeapShared::init_for_dumping(TRAPS) {
1585 if (HeapShared::can_write()) {
1586 setup_test_class(ArchiveHeapTestClass);
1587 _dumped_interned_strings = new (mtClass)DumpedInternedStrings();
1588 init_subgraph_entry_fields(CHECK);
1589 }
1590 }
1591
1592 void HeapShared::archive_object_subgraphs(ArchivableStaticFieldInfo fields[],
1593 bool is_full_module_graph) {
1594 _num_total_subgraph_recordings = 0;
1595 _num_total_walked_objs = 0;
1596 _num_total_archived_objs = 0;
1597 _num_total_recorded_klasses = 0;
1598 _num_total_verifications = 0;
1599
1600 // For each class X that has one or more archived fields:
1601 // [1] Dump the subgraph of each archived field
1602 // [2] Create a list of all the class of the objects that can be reached
1603 // by any of these static fields.
1604 // At runtime, these classes are initialized before X's archived fields
1605 // are restored by HeapShared::initialize_from_archived_subgraph().
1606 int i;
1607 for (int i = 0; fields[i].valid(); ) {
1608 ArchivableStaticFieldInfo* info = &fields[i];
1609 const char* klass_name = info->klass_name;
1610 start_recording_subgraph(info->klass, klass_name, is_full_module_graph);
1611
1612 // If you have specified consecutive fields of the same klass in
1613 // fields[], these will be archived in the same
1614 // {start_recording_subgraph ... done_recording_subgraph} pass to
1615 // save time.
1616 for (; fields[i].valid(); i++) {
1617 ArchivableStaticFieldInfo* f = &fields[i];
1618 if (f->klass_name != klass_name) {
1619 break;
1620 }
1621
1622 archive_reachable_objects_from_static_field(f->klass, f->klass_name,
1623 f->offset, f->field_name);
1624 }
1625 done_recording_subgraph(info->klass, klass_name);
1626 }
1627
1628 log_info(cds, heap)("Archived subgraph records = %d",
1629 _num_total_subgraph_recordings);
1630 log_info(cds, heap)(" Walked %d objects", _num_total_walked_objs);
1631 log_info(cds, heap)(" Archived %d objects", _num_total_archived_objs);
1632 log_info(cds, heap)(" Recorded %d klasses", _num_total_recorded_klasses);
1633
1634 #ifndef PRODUCT
1635 for (int i = 0; fields[i].valid(); i++) {
1636 ArchivableStaticFieldInfo* f = &fields[i];
1637 verify_subgraph_from_static_field(f->klass, f->offset);
1638 }
1639 log_info(cds, heap)(" Verified %d references", _num_total_verifications);
1640 #endif
1641 }
1642
1643 // Not all the strings in the global StringTable are dumped into the archive, because
1644 // some of those strings may be only referenced by classes that are excluded from
1645 // the archive. We need to explicitly mark the strings that are:
1646 // [1] used by classes that WILL be archived;
1647 // [2] included in the SharedArchiveConfigFile.
1648 void HeapShared::add_to_dumped_interned_strings(oop string) {
1649 assert_at_safepoint(); // DumpedInternedStrings uses raw oops
1650 assert(!ArchiveHeapWriter::is_string_too_large_to_archive(string), "must be");
1651 bool created;
1652 _dumped_interned_strings->put_if_absent(string, true, &created);
1653 }
1654
1655 #ifndef PRODUCT
1656 // At dump-time, find the location of all the non-null oop pointers in an archived heap
1657 // region. This way we can quickly relocate all the pointers without using
1658 // BasicOopIterateClosure at runtime.
1659 class FindEmbeddedNonNullPointers: public BasicOopIterateClosure {
1660 void* _start;
1661 BitMap *_oopmap;
1662 int _num_total_oops;
1663 int _num_null_oops;
1664 public:
1665 FindEmbeddedNonNullPointers(void* start, BitMap* oopmap)
1666 : _start(start), _oopmap(oopmap), _num_total_oops(0), _num_null_oops(0) {}
1667
1668 virtual void do_oop(narrowOop* p) {
1669 assert(UseCompressedOops, "sanity");
1670 _num_total_oops ++;
1671 narrowOop v = *p;
1672 if (!CompressedOops::is_null(v)) {
1673 // Note: HeapShared::to_requested_address() is not necessary because
1674 // the heap always starts at a deterministic address with UseCompressedOops==true.
1675 size_t idx = p - (narrowOop*)_start;
1676 _oopmap->set_bit(idx);
1677 } else {
1678 _num_null_oops ++;
1679 }
1680 }
1681 virtual void do_oop(oop* p) {
1682 assert(!UseCompressedOops, "sanity");
1683 _num_total_oops ++;
1684 if ((*p) != nullptr) {
1685 size_t idx = p - (oop*)_start;
1686 _oopmap->set_bit(idx);
1687 } else {
1688 _num_null_oops ++;
1689 }
1690 }
1691 int num_total_oops() const { return _num_total_oops; }
1692 int num_null_oops() const { return _num_null_oops; }
1693 };
1694 #endif
1695
1696 address HeapShared::to_requested_address(address dumptime_addr) {
1697 assert(DumpSharedSpaces, "static dump time only");
1698 if (dumptime_addr == nullptr || UseCompressedOops) {
1699 return dumptime_addr;
1700 }
1701
1702 // With UseCompressedOops==false, actual_base is selected by the OS so
1703 // it's different across -Xshare:dump runs.
1704 address actual_base = (address)G1CollectedHeap::heap()->reserved().start();
1705 address actual_end = (address)G1CollectedHeap::heap()->reserved().end();
1706 assert(actual_base <= dumptime_addr && dumptime_addr <= actual_end, "must be an address in the heap");
1707
1708 // We always write the objects as if the heap started at this address. This
1709 // makes the heap content deterministic.
1710 //
1711 // Note that at runtime, the heap address is also selected by the OS, so
1712 // the archive heap will not be mapped at 0x10000000. Instead, we will call
1713 // HeapShared::patch_embedded_pointers() to relocate the heap contents
1714 // accordingly.
1715 const address REQUESTED_BASE = (address)0x10000000;
1716 intx delta = REQUESTED_BASE - actual_base;
1717
1718 address requested_addr = dumptime_addr + delta;
1719 assert(REQUESTED_BASE != 0 && requested_addr != nullptr, "sanity");
1720 return requested_addr;
1721 }
1722
1723 #ifndef PRODUCT
1724 ResourceBitMap HeapShared::calculate_oopmap(MemRegion region) {
1725 size_t num_bits = region.byte_size() / (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop));
1726 ResourceBitMap oopmap(num_bits);
1727
1728 HeapWord* p = region.start();
1729 HeapWord* end = region.end();
1730 FindEmbeddedNonNullPointers finder((void*)p, &oopmap);
1731
1732 int num_objs = 0;
1733 while (p < end) {
1734 oop o = cast_to_oop(p);
1735 o->oop_iterate(&finder);
1736 p += o->size();
1737 ++ num_objs;
1738 }
1739
1740 log_info(cds, heap)("calculate_oopmap: objects = %6d, oop fields = %7d (nulls = %7d)",
1741 num_objs, finder.num_total_oops(), finder.num_null_oops());
1742 return oopmap;
1743 }
1744
1745 #endif // !PRODUCT
1746
1747 void HeapShared::count_allocation(size_t size) {
1748 _total_obj_count ++;
1749 _total_obj_size += size;
1750 for (int i = 0; i < ALLOC_STAT_SLOTS; i++) {
1751 if (size <= (size_t(1) << i)) {
1752 _alloc_count[i] ++;
1753 _alloc_size[i] += size;
1754 return;
1755 }
1756 }
1757 }
1758
1759 static double avg_size(size_t size, size_t count) {
1760 double avg = 0;
1761 if (count > 0) {
1762 avg = double(size * HeapWordSize) / double(count);
1763 }
1764 return avg;
1765 }
1766
1767 void HeapShared::print_stats() {
1768 size_t huge_count = _total_obj_count;
1769 size_t huge_size = _total_obj_size;
1770
1771 for (int i = 0; i < ALLOC_STAT_SLOTS; i++) {
1772 size_t byte_size_limit = (size_t(1) << i) * HeapWordSize;
1773 size_t count = _alloc_count[i];
1774 size_t size = _alloc_size[i];
1775 log_info(cds, heap)(SIZE_FORMAT_W(8) " objects are <= " SIZE_FORMAT_W(-6)
1776 " bytes (total " SIZE_FORMAT_W(8) " bytes, avg %8.1f bytes)",
1777 count, byte_size_limit, size * HeapWordSize, avg_size(size, count));
1778 huge_count -= count;
1779 huge_size -= size;
1780 }
1781
1782 log_info(cds, heap)(SIZE_FORMAT_W(8) " huge objects (total " SIZE_FORMAT_W(8) " bytes"
1783 ", avg %8.1f bytes)",
1784 huge_count, huge_size * HeapWordSize,
1785 avg_size(huge_size, huge_count));
1786 log_info(cds, heap)(SIZE_FORMAT_W(8) " total objects (total " SIZE_FORMAT_W(8) " bytes"
1787 ", avg %8.1f bytes)",
1788 _total_obj_count, _total_obj_size * HeapWordSize,
1789 avg_size(_total_obj_size, _total_obj_count));
1790 }
1791
1792 #endif // INCLUDE_CDS_JAVA_HEAP