1 /*
2 * Copyright (c) 2023, 2025, 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/aotReferenceObjSupport.hpp"
26 #include "cds/archiveHeapWriter.hpp"
27 #include "cds/cdsConfig.hpp"
28 #include "cds/filemap.hpp"
29 #include "cds/heapShared.hpp"
30 #include "cds/regeneratedClasses.hpp"
31 #include "classfile/javaClasses.hpp"
32 #include "classfile/modules.hpp"
33 #include "classfile/systemDictionary.hpp"
34 #include "gc/shared/collectedHeap.hpp"
35 #include "memory/iterator.inline.hpp"
36 #include "memory/oopFactory.hpp"
37 #include "memory/universe.hpp"
38 #include "oops/compressedOops.hpp"
39 #include "oops/objArrayOop.inline.hpp"
40 #include "oops/oop.inline.hpp"
41 #include "oops/oopHandle.inline.hpp"
42 #include "oops/typeArrayKlass.hpp"
43 #include "oops/typeArrayOop.hpp"
44 #include "runtime/java.hpp"
45 #include "runtime/mutexLocker.hpp"
46 #include "utilities/bitMap.inline.hpp"
47 #if INCLUDE_G1GC
48 #include "gc/g1/g1CollectedHeap.hpp"
49 #include "gc/g1/g1HeapRegion.hpp"
50 #endif
51
52 #if INCLUDE_CDS_JAVA_HEAP
53
54 GrowableArrayCHeap<u1, mtClassShared>* ArchiveHeapWriter::_buffer = nullptr;
55
56 // The following are offsets from buffer_bottom()
57 size_t ArchiveHeapWriter::_buffer_used;
58
59 // Heap root segments
60 HeapRootSegments ArchiveHeapWriter::_heap_root_segments;
61
62 address ArchiveHeapWriter::_requested_bottom;
63 address ArchiveHeapWriter::_requested_top;
64
65 static size_t _num_strings = 0;
66 static size_t _string_bytes = 0;
67 static size_t _num_packages = 0;
68 static size_t _num_protection_domains = 0;
69
70 GrowableArrayCHeap<ArchiveHeapWriter::NativePointerInfo, mtClassShared>* ArchiveHeapWriter::_native_pointers;
71 GrowableArrayCHeap<oop, mtClassShared>* ArchiveHeapWriter::_source_objs;
72 GrowableArrayCHeap<ArchiveHeapWriter::HeapObjOrder, mtClassShared>* ArchiveHeapWriter::_source_objs_order;
73
74 ArchiveHeapWriter::BufferOffsetToSourceObjectTable*
75 ArchiveHeapWriter::_buffer_offset_to_source_obj_table = nullptr;
76
77
78 typedef HashTable<
79 size_t, // offset of a filler from ArchiveHeapWriter::buffer_bottom()
80 size_t, // size of this filler (in bytes)
81 127, // prime number
82 AnyObj::C_HEAP,
83 mtClassShared> FillersTable;
84 static FillersTable* _fillers;
85 static int _num_native_ptrs = 0;
86
87 void ArchiveHeapWriter::init() {
88 if (CDSConfig::is_dumping_heap()) {
89 Universe::heap()->collect(GCCause::_java_lang_system_gc);
90
91 _buffer_offset_to_source_obj_table = new BufferOffsetToSourceObjectTable(/*size (prime)*/36137, /*max size*/1 * M);
92 _fillers = new FillersTable();
93 _requested_bottom = nullptr;
94 _requested_top = nullptr;
95
96 _native_pointers = new GrowableArrayCHeap<NativePointerInfo, mtClassShared>(2048);
97 _source_objs = new GrowableArrayCHeap<oop, mtClassShared>(10000);
98
99 guarantee(MIN_GC_REGION_ALIGNMENT <= G1HeapRegion::min_region_size_in_words() * HeapWordSize, "must be");
100 }
101 }
102
103 void ArchiveHeapWriter::delete_tables_with_raw_oops() {
104 delete _source_objs;
105 _source_objs = nullptr;
106 }
107
108 void ArchiveHeapWriter::add_source_obj(oop src_obj) {
109 _source_objs->append(src_obj);
110 }
111
112 void ArchiveHeapWriter::write(GrowableArrayCHeap<oop, mtClassShared>* roots,
113 ArchiveHeapInfo* heap_info) {
114 assert(CDSConfig::is_dumping_heap(), "sanity");
115 allocate_buffer();
116 copy_source_objs_to_buffer(roots);
117 set_requested_address(heap_info);
118 relocate_embedded_oops(roots, heap_info);
119 }
120
121 bool ArchiveHeapWriter::is_too_large_to_archive(oop o) {
122 return is_too_large_to_archive(o->size());
123 }
124
125 bool ArchiveHeapWriter::is_string_too_large_to_archive(oop string) {
126 typeArrayOop value = java_lang_String::value_no_keepalive(string);
127 return is_too_large_to_archive(value);
128 }
129
130 bool ArchiveHeapWriter::is_too_large_to_archive(size_t size) {
131 assert(size > 0, "no zero-size object");
132 assert(size * HeapWordSize > size, "no overflow");
133 static_assert(MIN_GC_REGION_ALIGNMENT > 0, "must be positive");
134
135 size_t byte_size = size * HeapWordSize;
136 if (byte_size > size_t(MIN_GC_REGION_ALIGNMENT)) {
137 return true;
138 } else {
139 return false;
140 }
141 }
142
143 // Various lookup functions between source_obj, buffered_obj and requested_obj
144 bool ArchiveHeapWriter::is_in_requested_range(oop o) {
145 assert(_requested_bottom != nullptr, "do not call before _requested_bottom is initialized");
146 address a = cast_from_oop<address>(o);
147 return (_requested_bottom <= a && a < _requested_top);
148 }
149
150 oop ArchiveHeapWriter::requested_obj_from_buffer_offset(size_t offset) {
151 oop req_obj = cast_to_oop(_requested_bottom + offset);
152 assert(is_in_requested_range(req_obj), "must be");
153 return req_obj;
154 }
155
156 oop ArchiveHeapWriter::source_obj_to_requested_obj(oop src_obj) {
157 assert(CDSConfig::is_dumping_heap(), "dump-time only");
158 HeapShared::CachedOopInfo* p = HeapShared::get_cached_oop_info(src_obj);
159 if (p != nullptr) {
160 return requested_obj_from_buffer_offset(p->buffer_offset());
161 } else {
162 return nullptr;
163 }
164 }
165
166 oop ArchiveHeapWriter::buffered_addr_to_source_obj(address buffered_addr) {
167 OopHandle* oh = _buffer_offset_to_source_obj_table->get(buffered_address_to_offset(buffered_addr));
168 if (oh != nullptr) {
169 return oh->resolve();
170 } else {
171 return nullptr;
172 }
173 }
174
175 Klass* ArchiveHeapWriter::real_klass_of_buffered_oop(address buffered_addr) {
176 oop p = buffered_addr_to_source_obj(buffered_addr);
177 if (p != nullptr) {
178 return p->klass();
179 } else if (get_filler_size_at(buffered_addr) > 0) {
180 return Universe::fillerArrayKlass();
181 } else {
182 // This is one of the root segments
183 return Universe::objectArrayKlass();
184 }
185 }
186
187 size_t ArchiveHeapWriter::size_of_buffered_oop(address buffered_addr) {
188 oop p = buffered_addr_to_source_obj(buffered_addr);
189 if (p != nullptr) {
190 return p->size();
191 }
192
193 size_t nbytes = get_filler_size_at(buffered_addr);
194 if (nbytes > 0) {
195 assert((nbytes % BytesPerWord) == 0, "should be aligned");
196 return nbytes / BytesPerWord;
197 }
198
199 address hrs = buffer_bottom();
200 for (size_t seg_idx = 0; seg_idx < _heap_root_segments.count(); seg_idx++) {
201 nbytes = _heap_root_segments.size_in_bytes(seg_idx);
202 if (hrs == buffered_addr) {
203 assert((nbytes % BytesPerWord) == 0, "should be aligned");
204 return nbytes / BytesPerWord;
205 }
206 hrs += nbytes;
207 }
208
209 ShouldNotReachHere();
210 return 0;
211 }
212
213 address ArchiveHeapWriter::buffered_addr_to_requested_addr(address buffered_addr) {
214 return _requested_bottom + buffered_address_to_offset(buffered_addr);
215 }
216
217 address ArchiveHeapWriter::requested_address() {
218 assert(_buffer != nullptr, "must be initialized");
219 return _requested_bottom;
220 }
221
222 void ArchiveHeapWriter::allocate_buffer() {
223 int initial_buffer_size = 100000;
224 _buffer = new GrowableArrayCHeap<u1, mtClassShared>(initial_buffer_size);
225 _buffer_used = 0;
226 ensure_buffer_space(1); // so that buffer_bottom() works
227 }
228
229 void ArchiveHeapWriter::ensure_buffer_space(size_t min_bytes) {
230 // We usually have very small heaps. If we get a huge one it's probably caused by a bug.
231 guarantee(min_bytes <= max_jint, "we dont support archiving more than 2G of objects");
232 _buffer->at_grow(to_array_index(min_bytes));
233 }
234
235 objArrayOop ArchiveHeapWriter::allocate_root_segment(size_t offset, int element_count) {
236 HeapWord* mem = offset_to_buffered_address<HeapWord *>(offset);
237 memset(mem, 0, objArrayOopDesc::object_size(element_count));
238
239 // The initialization code is copied from MemAllocator::finish and ObjArrayAllocator::initialize.
240 if (UseCompactObjectHeaders) {
241 oopDesc::release_set_mark(mem, Universe::objectArrayKlass()->prototype_header());
242 } else {
243 oopDesc::set_mark(mem, markWord::prototype());
244 oopDesc::release_set_klass(mem, Universe::objectArrayKlass());
245 }
246 arrayOopDesc::set_length(mem, element_count);
247 return objArrayOop(cast_to_oop(mem));
248 }
249
250 void ArchiveHeapWriter::root_segment_at_put(objArrayOop segment, int index, oop root) {
251 // Do not use arrayOop->obj_at_put(i, o) as arrayOop is outside the real heap!
252 if (UseCompressedOops) {
253 *segment->obj_at_addr<narrowOop>(index) = CompressedOops::encode(root);
254 } else {
255 *segment->obj_at_addr<oop>(index) = root;
256 }
257 }
258
259 void ArchiveHeapWriter::copy_roots_to_buffer(GrowableArrayCHeap<oop, mtClassShared>* roots) {
260 // Depending on the number of classes we are archiving, a single roots array may be
261 // larger than MIN_GC_REGION_ALIGNMENT. Roots are allocated first in the buffer, which
262 // allows us to chop the large array into a series of "segments". Current layout
263 // starts with zero or more segments exactly fitting MIN_GC_REGION_ALIGNMENT, and end
264 // with a single segment that may be smaller than MIN_GC_REGION_ALIGNMENT.
265 // This is simple and efficient. We do not need filler objects anywhere between the segments,
266 // or immediately after the last segment. This allows starting the object dump immediately
267 // after the roots.
268
269 assert((_buffer_used % MIN_GC_REGION_ALIGNMENT) == 0,
270 "Pre-condition: Roots start at aligned boundary: %zu", _buffer_used);
271
272 int max_elem_count = ((MIN_GC_REGION_ALIGNMENT - arrayOopDesc::header_size_in_bytes()) / heapOopSize);
273 assert(objArrayOopDesc::object_size(max_elem_count)*HeapWordSize == MIN_GC_REGION_ALIGNMENT,
274 "Should match exactly");
275
276 HeapRootSegments segments(_buffer_used,
277 roots->length(),
278 MIN_GC_REGION_ALIGNMENT,
279 max_elem_count);
280
281 int root_index = 0;
282 for (size_t seg_idx = 0; seg_idx < segments.count(); seg_idx++) {
283 int size_elems = segments.size_in_elems(seg_idx);
284 size_t size_bytes = segments.size_in_bytes(seg_idx);
285
286 size_t oop_offset = _buffer_used;
287 _buffer_used = oop_offset + size_bytes;
288 ensure_buffer_space(_buffer_used);
289
290 assert((oop_offset % MIN_GC_REGION_ALIGNMENT) == 0,
291 "Roots segment %zu start is not aligned: %zu",
292 segments.count(), oop_offset);
293
294 objArrayOop seg_oop = allocate_root_segment(oop_offset, size_elems);
295 for (int i = 0; i < size_elems; i++) {
296 root_segment_at_put(seg_oop, i, roots->at(root_index++));
297 }
298
299 log_info(aot, heap)("archived obj root segment [%d] = %zu bytes, obj = " PTR_FORMAT,
300 size_elems, size_bytes, p2i(seg_oop));
301 }
302
303 assert(root_index == roots->length(), "Post-condition: All roots are handled");
304
305 _heap_root_segments = segments;
306 }
307
308 // The goal is to sort the objects in increasing order of:
309 // - objects that have only oop pointers
310 // - objects that have both native and oop pointers
311 // - objects that have only native pointers
312 // - objects that have no pointers
313 static int oop_sorting_rank(oop o) {
314 bool has_oop_ptr, has_native_ptr;
315 HeapShared::get_pointer_info(o, has_oop_ptr, has_native_ptr);
316
317 if (has_oop_ptr) {
318 if (!has_native_ptr) {
319 return 0;
320 } else {
321 return 1;
322 }
323 } else {
324 if (has_native_ptr) {
325 return 2;
326 } else {
327 return 3;
328 }
329 }
330 }
331
332 int ArchiveHeapWriter::compare_objs_by_oop_fields(HeapObjOrder* a, HeapObjOrder* b) {
333 int rank_a = a->_rank;
334 int rank_b = b->_rank;
335
336 if (rank_a != rank_b) {
337 return rank_a - rank_b;
338 } else {
339 // If they are the same rank, sort them by their position in the _source_objs array
340 return a->_index - b->_index;
341 }
342 }
343
344 void ArchiveHeapWriter::sort_source_objs() {
345 log_info(aot)("sorting heap objects");
346 int len = _source_objs->length();
347 _source_objs_order = new GrowableArrayCHeap<HeapObjOrder, mtClassShared>(len);
348
349 for (int i = 0; i < len; i++) {
350 oop o = _source_objs->at(i);
351 int rank = oop_sorting_rank(o);
352 HeapObjOrder os = {i, rank};
353 _source_objs_order->append(os);
354 }
355 log_info(aot)("computed ranks");
356 _source_objs_order->sort(compare_objs_by_oop_fields);
357 log_info(aot)("sorting heap objects done");
358 }
359
360 void ArchiveHeapWriter::copy_source_objs_to_buffer(GrowableArrayCHeap<oop, mtClassShared>* roots) {
361 // There could be multiple root segments, which we want to be aligned by region.
362 // Putting them ahead of objects makes sure we waste no space.
363 copy_roots_to_buffer(roots);
364
365 sort_source_objs();
366 for (int i = 0; i < _source_objs_order->length(); i++) {
367 int src_obj_index = _source_objs_order->at(i)._index;
368 oop src_obj = _source_objs->at(src_obj_index);
369 HeapShared::CachedOopInfo* info = HeapShared::get_cached_oop_info(src_obj);
370 assert(info != nullptr, "must be");
371 size_t buffer_offset = copy_one_source_obj_to_buffer(src_obj);
372 info->set_buffer_offset(buffer_offset);
373 assert(buffer_offset <= 0x7fffffff, "sanity");
374 HeapShared::add_to_permanent_oop_table(src_obj, (int)buffer_offset);
375
376 OopHandle handle(Universe::vm_global(), src_obj);
377 _buffer_offset_to_source_obj_table->put_when_absent(buffer_offset, handle);
378 _buffer_offset_to_source_obj_table->maybe_grow();
379
380 if (java_lang_Module::is_instance(src_obj)) {
381 Modules::check_archived_module_oop(src_obj);
382 }
383 }
384
385 log_info(aot)("Size of heap region = %zu bytes, %d objects, %d roots, %d native ptrs",
386 _buffer_used, _source_objs->length() + 1, roots->length(), _num_native_ptrs);
387 log_info(cds)(" strings = %8zu (%zu bytes)", _num_strings, _string_bytes);
388 log_info(cds)(" packages = %8zu", _num_packages);
389 log_info(cds)(" protection domains = %8zu", _num_protection_domains);
390 }
391
392 size_t ArchiveHeapWriter::filler_array_byte_size(int length) {
393 size_t byte_size = objArrayOopDesc::object_size(length) * HeapWordSize;
394 return byte_size;
395 }
396
397 int ArchiveHeapWriter::filler_array_length(size_t fill_bytes) {
398 assert(is_object_aligned(fill_bytes), "must be");
399 size_t elemSize = (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop));
400
401 int initial_length = to_array_length(fill_bytes / elemSize);
402 for (int length = initial_length; length >= 0; length --) {
403 size_t array_byte_size = filler_array_byte_size(length);
404 if (array_byte_size == fill_bytes) {
405 return length;
406 }
407 }
408
409 ShouldNotReachHere();
410 return -1;
411 }
412
413 HeapWord* ArchiveHeapWriter::init_filler_array_at_buffer_top(int array_length, size_t fill_bytes) {
414 assert(UseCompressedClassPointers, "Archived heap only supported for compressed klasses");
415 Klass* oak = Universe::objectArrayKlass(); // already relocated to point to archived klass
416 HeapWord* mem = offset_to_buffered_address<HeapWord*>(_buffer_used);
417 memset(mem, 0, fill_bytes);
418 narrowKlass nk = ArchiveBuilder::current()->get_requested_narrow_klass(oak);
419 if (UseCompactObjectHeaders) {
420 oopDesc::release_set_mark(mem, markWord::prototype().set_narrow_klass(nk));
421 } else {
422 oopDesc::set_mark(mem, markWord::prototype());
423 cast_to_oop(mem)->set_narrow_klass(nk);
424 }
425 arrayOopDesc::set_length(mem, array_length);
426 return mem;
427 }
428
429 void ArchiveHeapWriter::maybe_fill_gc_region_gap(size_t required_byte_size) {
430 // We fill only with arrays (so we don't need to use a single HeapWord filler if the
431 // leftover space is smaller than a zero-sized array object). Therefore, we need to
432 // make sure there's enough space of min_filler_byte_size in the current region after
433 // required_byte_size has been allocated. If not, fill the remainder of the current
434 // region.
435 size_t min_filler_byte_size = filler_array_byte_size(0);
436 size_t new_used = _buffer_used + required_byte_size + min_filler_byte_size;
437
438 const size_t cur_min_region_bottom = align_down(_buffer_used, MIN_GC_REGION_ALIGNMENT);
439 const size_t next_min_region_bottom = align_down(new_used, MIN_GC_REGION_ALIGNMENT);
440
441 if (cur_min_region_bottom != next_min_region_bottom) {
442 // Make sure that no objects span across MIN_GC_REGION_ALIGNMENT. This way
443 // we can map the region in any region-based collector.
444 assert(next_min_region_bottom > cur_min_region_bottom, "must be");
445 assert(next_min_region_bottom - cur_min_region_bottom == MIN_GC_REGION_ALIGNMENT,
446 "no buffered object can be larger than %d bytes", MIN_GC_REGION_ALIGNMENT);
447
448 const size_t filler_end = next_min_region_bottom;
449 const size_t fill_bytes = filler_end - _buffer_used;
450 assert(fill_bytes > 0, "must be");
451 ensure_buffer_space(filler_end);
452
453 int array_length = filler_array_length(fill_bytes);
454 log_info(aot, heap)("Inserting filler obj array of %d elements (%zu bytes total) @ buffer offset %zu",
455 array_length, fill_bytes, _buffer_used);
456 HeapWord* filler = init_filler_array_at_buffer_top(array_length, fill_bytes);
457 _buffer_used = filler_end;
458 _fillers->put(buffered_address_to_offset((address)filler), fill_bytes);
459 }
460 }
461
462 size_t ArchiveHeapWriter::get_filler_size_at(address buffered_addr) {
463 size_t* p = _fillers->get(buffered_address_to_offset(buffered_addr));
464 if (p != nullptr) {
465 assert(*p > 0, "filler must be larger than zero bytes");
466 return *p;
467 } else {
468 return 0; // buffered_addr is not a filler
469 }
470 }
471
472 template <typename T>
473 void update_buffered_object_field(address buffered_obj, int field_offset, T value) {
474 T* field_addr = cast_to_oop(buffered_obj)->field_addr<T>(field_offset);
475 *field_addr = value;
476 }
477
478 void ArchiveHeapWriter::update_stats(oop src_obj) {
479 if (java_lang_String::is_instance(src_obj)) {
480 _num_strings ++;
481 _string_bytes += src_obj->size() * HeapWordSize;
482 _string_bytes += java_lang_String::value(src_obj)->size() * HeapWordSize;
483 } else {
484 Klass* k = src_obj->klass();
485 Symbol* name = k->name();
486 if (name->equals("java/lang/NamedPackage") || name->equals("java/lang/Package")) {
487 _num_packages ++;
488 } else if (name->equals("java/security/ProtectionDomain")) {
489 _num_protection_domains ++;
490 }
491 }
492 }
493
494 size_t ArchiveHeapWriter::copy_one_source_obj_to_buffer(oop src_obj) {
495 update_stats(src_obj);
496
497 assert(!is_too_large_to_archive(src_obj), "already checked");
498 size_t byte_size = src_obj->size() * HeapWordSize;
499 assert(byte_size > 0, "no zero-size objects");
500
501 // For region-based collectors such as G1, the archive heap may be mapped into
502 // multiple regions. We need to make sure that we don't have an object that can possible
503 // span across two regions.
504 maybe_fill_gc_region_gap(byte_size);
505
506 size_t new_used = _buffer_used + byte_size;
507 assert(new_used > _buffer_used, "no wrap around");
508
509 size_t cur_min_region_bottom = align_down(_buffer_used, MIN_GC_REGION_ALIGNMENT);
510 size_t next_min_region_bottom = align_down(new_used, MIN_GC_REGION_ALIGNMENT);
511 assert(cur_min_region_bottom == next_min_region_bottom, "no object should cross minimal GC region boundaries");
512
513 ensure_buffer_space(new_used);
514
515 address from = cast_from_oop<address>(src_obj);
516 address to = offset_to_buffered_address<address>(_buffer_used);
517 assert(is_object_aligned(_buffer_used), "sanity");
518 assert(is_object_aligned(byte_size), "sanity");
519 memcpy(to, from, byte_size);
520
521 // These native pointers will be restored explicitly at run time.
522 if (java_lang_Module::is_instance(src_obj)) {
523 update_buffered_object_field<ModuleEntry*>(to, java_lang_Module::module_entry_offset(), nullptr);
524 } else if (java_lang_ClassLoader::is_instance(src_obj)) {
525 #ifdef ASSERT
526 // We only archive these loaders
527 if (src_obj != SystemDictionary::java_platform_loader() &&
528 src_obj != SystemDictionary::java_system_loader()) {
529 assert(src_obj->klass()->name()->equals("jdk/internal/loader/ClassLoaders$BootClassLoader"), "must be");
530 }
531 #endif
532 update_buffered_object_field<ClassLoaderData*>(to, java_lang_ClassLoader::loader_data_offset(), nullptr);
533 }
534
535 size_t buffered_obj_offset = _buffer_used;
536 _buffer_used = new_used;
537
538 return buffered_obj_offset;
539 }
540
541 void ArchiveHeapWriter::set_requested_address(ArchiveHeapInfo* info) {
542 assert(!info->is_used(), "only set once");
543
544 size_t heap_region_byte_size = _buffer_used;
545 assert(heap_region_byte_size > 0, "must archived at least one object!");
546
547 if (UseCompressedOops) {
548 if (UseG1GC) {
549 address heap_end = (address)G1CollectedHeap::heap()->reserved().end();
550 log_info(aot, heap)("Heap end = %p", heap_end);
551 _requested_bottom = align_down(heap_end - heap_region_byte_size, G1HeapRegion::GrainBytes);
552 _requested_bottom = align_down(_requested_bottom, MIN_GC_REGION_ALIGNMENT);
553 assert(is_aligned(_requested_bottom, G1HeapRegion::GrainBytes), "sanity");
554 } else {
555 _requested_bottom = align_up(CompressedOops::begin(), MIN_GC_REGION_ALIGNMENT);
556 }
557 } else {
558 // We always write the objects as if the heap started at this address. This
559 // makes the contents of the archive heap deterministic.
560 //
561 // Note that at runtime, the heap address is selected by the OS, so the archive
562 // heap will not be mapped at 0x10000000, and the contents need to be patched.
563 _requested_bottom = align_up((address)NOCOOPS_REQUESTED_BASE, MIN_GC_REGION_ALIGNMENT);
564 }
565
566 assert(is_aligned(_requested_bottom, MIN_GC_REGION_ALIGNMENT), "sanity");
567
568 _requested_top = _requested_bottom + _buffer_used;
569
570 info->set_buffer_region(MemRegion(offset_to_buffered_address<HeapWord*>(0),
571 offset_to_buffered_address<HeapWord*>(_buffer_used)));
572 info->set_heap_root_segments(_heap_root_segments);
573 }
574
575 // Oop relocation
576
577 template <typename T> T* ArchiveHeapWriter::requested_addr_to_buffered_addr(T* p) {
578 assert(is_in_requested_range(cast_to_oop(p)), "must be");
579
580 address addr = address(p);
581 assert(addr >= _requested_bottom, "must be");
582 size_t offset = addr - _requested_bottom;
583 return offset_to_buffered_address<T*>(offset);
584 }
585
586 template <typename T> oop ArchiveHeapWriter::load_source_oop_from_buffer(T* buffered_addr) {
587 oop o = load_oop_from_buffer(buffered_addr);
588 assert(!in_buffer(cast_from_oop<address>(o)), "must point to source oop");
589 return o;
590 }
591
592 template <typename T> void ArchiveHeapWriter::store_requested_oop_in_buffer(T* buffered_addr,
593 oop request_oop) {
594 assert(is_in_requested_range(request_oop), "must be");
595 store_oop_in_buffer(buffered_addr, request_oop);
596 }
597
598 inline void ArchiveHeapWriter::store_oop_in_buffer(oop* buffered_addr, oop requested_obj) {
599 *buffered_addr = requested_obj;
600 }
601
602 inline void ArchiveHeapWriter::store_oop_in_buffer(narrowOop* buffered_addr, oop requested_obj) {
603 narrowOop val = CompressedOops::encode_not_null(requested_obj);
604 *buffered_addr = val;
605 }
606
607 oop ArchiveHeapWriter::load_oop_from_buffer(oop* buffered_addr) {
608 return *buffered_addr;
609 }
610
611 oop ArchiveHeapWriter::load_oop_from_buffer(narrowOop* buffered_addr) {
612 return CompressedOops::decode(*buffered_addr);
613 }
614
615 template <typename T> void ArchiveHeapWriter::relocate_field_in_buffer(T* field_addr_in_buffer, CHeapBitMap* oopmap) {
616 oop source_referent = load_source_oop_from_buffer<T>(field_addr_in_buffer);
617 if (source_referent != nullptr) {
618 if (java_lang_Class::is_instance(source_referent)) {
619 Klass* k = java_lang_Class::as_Klass(source_referent);
620 if (RegeneratedClasses::has_been_regenerated(k)) {
621 source_referent = RegeneratedClasses::get_regenerated_object(k)->java_mirror();
622 }
623 // When the source object points to a "real" mirror, the buffered object should point
624 // to the "scratch" mirror, which has all unarchivable fields scrubbed (to be reinstated
625 // at run time).
626 source_referent = HeapShared::scratch_java_mirror(source_referent);
627 assert(source_referent != nullptr, "must be");
628 }
629 oop request_referent = source_obj_to_requested_obj(source_referent);
630 store_requested_oop_in_buffer<T>(field_addr_in_buffer, request_referent);
631 mark_oop_pointer<T>(field_addr_in_buffer, oopmap);
632 }
633 }
634
635 template <typename T> void ArchiveHeapWriter::mark_oop_pointer(T* buffered_addr, CHeapBitMap* oopmap) {
636 T* request_p = (T*)(buffered_addr_to_requested_addr((address)buffered_addr));
637 address requested_region_bottom;
638
639 assert(request_p >= (T*)_requested_bottom, "sanity");
640 assert(request_p < (T*)_requested_top, "sanity");
641 requested_region_bottom = _requested_bottom;
642
643 // Mark the pointer in the oopmap
644 T* region_bottom = (T*)requested_region_bottom;
645 assert(request_p >= region_bottom, "must be");
646 BitMap::idx_t idx = request_p - region_bottom;
647 assert(idx < oopmap->size(), "overflow");
648 oopmap->set_bit(idx);
649 }
650
651 void ArchiveHeapWriter::update_header_for_requested_obj(oop requested_obj, oop src_obj, Klass* src_klass) {
652 assert(UseCompressedClassPointers, "Archived heap only supported for compressed klasses");
653 narrowKlass nk = ArchiveBuilder::current()->get_requested_narrow_klass(src_klass);
654 address buffered_addr = requested_addr_to_buffered_addr(cast_from_oop<address>(requested_obj));
655
656 oop fake_oop = cast_to_oop(buffered_addr);
657 if (UseCompactObjectHeaders) {
658 fake_oop->set_mark(markWord::prototype().set_narrow_klass(nk));
659 } else {
660 fake_oop->set_narrow_klass(nk);
661 }
662
663 if (src_obj == nullptr) {
664 return;
665 }
666 // We need to retain the identity_hash, because it may have been used by some hashtables
667 // in the shared heap.
668 if (!src_obj->fast_no_hash_check()) {
669 intptr_t src_hash = src_obj->identity_hash();
670 if (UseCompactObjectHeaders) {
671 fake_oop->set_mark(markWord::prototype().set_narrow_klass(nk).copy_set_hash(src_hash));
672 } else {
673 fake_oop->set_mark(markWord::prototype().copy_set_hash(src_hash));
674 }
675 assert(fake_oop->mark().is_unlocked(), "sanity");
676
677 DEBUG_ONLY(intptr_t archived_hash = fake_oop->identity_hash());
678 assert(src_hash == archived_hash, "Different hash codes: original " INTPTR_FORMAT ", archived " INTPTR_FORMAT, src_hash, archived_hash);
679 }
680 // Strip age bits.
681 fake_oop->set_mark(fake_oop->mark().set_age(0));
682 }
683
684 class ArchiveHeapWriter::EmbeddedOopRelocator: public BasicOopIterateClosure {
685 oop _src_obj;
686 address _buffered_obj;
687 CHeapBitMap* _oopmap;
688 bool _is_java_lang_ref;
689 public:
690 EmbeddedOopRelocator(oop src_obj, address buffered_obj, CHeapBitMap* oopmap) :
691 _src_obj(src_obj), _buffered_obj(buffered_obj), _oopmap(oopmap)
692 {
693 _is_java_lang_ref = AOTReferenceObjSupport::check_if_ref_obj(src_obj);
694 }
695
696 void do_oop(narrowOop *p) { EmbeddedOopRelocator::do_oop_work(p); }
697 void do_oop( oop *p) { EmbeddedOopRelocator::do_oop_work(p); }
698
699 private:
700 template <class T> void do_oop_work(T *p) {
701 int field_offset = pointer_delta_as_int((char*)p, cast_from_oop<char*>(_src_obj));
702 T* field_addr = (T*)(_buffered_obj + field_offset);
703 if (_is_java_lang_ref && AOTReferenceObjSupport::skip_field(field_offset)) {
704 // Do not copy these fields. Set them to null
705 *field_addr = (T)0x0;
706 } else {
707 ArchiveHeapWriter::relocate_field_in_buffer<T>(field_addr, _oopmap);
708 }
709 }
710 };
711
712 static void log_bitmap_usage(const char* which, BitMap* bitmap, size_t total_bits) {
713 // The whole heap is covered by total_bits, but there are only non-zero bits within [start ... end).
714 size_t start = bitmap->find_first_set_bit(0);
715 size_t end = bitmap->size();
716 log_info(aot)("%s = %7zu ... %7zu (%3zu%% ... %3zu%% = %3zu%%)", which,
717 start, end,
718 start * 100 / total_bits,
719 end * 100 / total_bits,
720 (end - start) * 100 / total_bits);
721 }
722
723 // Update all oop fields embedded in the buffered objects
724 void ArchiveHeapWriter::relocate_embedded_oops(GrowableArrayCHeap<oop, mtClassShared>* roots,
725 ArchiveHeapInfo* heap_info) {
726 size_t oopmap_unit = (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop));
727 size_t heap_region_byte_size = _buffer_used;
728 heap_info->oopmap()->resize(heap_region_byte_size / oopmap_unit);
729
730 for (int i = 0; i < _source_objs_order->length(); i++) {
731 int src_obj_index = _source_objs_order->at(i)._index;
732 oop src_obj = _source_objs->at(src_obj_index);
733 HeapShared::CachedOopInfo* info = HeapShared::get_cached_oop_info(src_obj);
734 assert(info != nullptr, "must be");
735 oop requested_obj = requested_obj_from_buffer_offset(info->buffer_offset());
736 update_header_for_requested_obj(requested_obj, src_obj, src_obj->klass());
737 address buffered_obj = offset_to_buffered_address<address>(info->buffer_offset());
738 EmbeddedOopRelocator relocator(src_obj, buffered_obj, heap_info->oopmap());
739 src_obj->oop_iterate(&relocator);
740 };
741
742 // Relocate HeapShared::roots(), which is created in copy_roots_to_buffer() and
743 // doesn't have a corresponding src_obj, so we can't use EmbeddedOopRelocator on it.
744 for (size_t seg_idx = 0; seg_idx < _heap_root_segments.count(); seg_idx++) {
745 size_t seg_offset = _heap_root_segments.segment_offset(seg_idx);
746
747 objArrayOop requested_obj = (objArrayOop)requested_obj_from_buffer_offset(seg_offset);
748 update_header_for_requested_obj(requested_obj, nullptr, Universe::objectArrayKlass());
749 address buffered_obj = offset_to_buffered_address<address>(seg_offset);
750 int length = _heap_root_segments.size_in_elems(seg_idx);
751
752 if (UseCompressedOops) {
753 for (int i = 0; i < length; i++) {
754 narrowOop* addr = (narrowOop*)(buffered_obj + objArrayOopDesc::obj_at_offset<narrowOop>(i));
755 relocate_field_in_buffer<narrowOop>(addr, heap_info->oopmap());
756 }
757 } else {
758 for (int i = 0; i < length; i++) {
759 oop* addr = (oop*)(buffered_obj + objArrayOopDesc::obj_at_offset<oop>(i));
760 relocate_field_in_buffer<oop>(addr, heap_info->oopmap());
761 }
762 }
763 }
764
765 compute_ptrmap(heap_info);
766
767 size_t total_bytes = (size_t)_buffer->length();
768 log_bitmap_usage("oopmap", heap_info->oopmap(), total_bytes / (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop)));
769 log_bitmap_usage("ptrmap", heap_info->ptrmap(), total_bytes / sizeof(address));
770 }
771
772 void ArchiveHeapWriter::mark_native_pointer(oop src_obj, int field_offset) {
773 Metadata* ptr = src_obj->metadata_field_acquire(field_offset);
774 if (ptr != nullptr) {
775 NativePointerInfo info;
776 info._src_obj = src_obj;
777 info._field_offset = field_offset;
778 _native_pointers->append(info);
779 HeapShared::set_has_native_pointers(src_obj);
780 _num_native_ptrs ++;
781 }
782 }
783
784 // Do we have a jlong/jint field that's actually a pointer to a MetaspaceObj?
785 bool ArchiveHeapWriter::is_marked_as_native_pointer(ArchiveHeapInfo* heap_info, address buffered_obj, int field_offset) {
786 size_t offset = buffered_address_to_offset(buffered_obj) + checked_cast<size_t>(field_offset); // in bytes
787 BitMap::idx_t idx = checked_cast<BitMap::idx_t>(offset) / HeapWordSize;
788 // Leading zeros have been removed so some addresses may not be in the ptrmap
789 size_t start_pos = FileMapInfo::current_info()->heap_ptrmap_start_pos();
790 if (idx < start_pos) {
791 return false;
792 } else {
793 idx -= start_pos;
794 }
795 return (idx < heap_info->ptrmap()->size()) && (heap_info->ptrmap()->at(idx) == true);
796 }
797
798 void ArchiveHeapWriter::compute_ptrmap(ArchiveHeapInfo* heap_info) {
799 int num_non_null_ptrs = 0;
800 Metadata** bottom = (Metadata**) _requested_bottom;
801 Metadata** top = (Metadata**) _requested_top; // exclusive
802 heap_info->ptrmap()->resize(top - bottom);
803
804 BitMap::idx_t max_idx = 32; // paranoid - don't make it too small
805 for (int i = 0; i < _native_pointers->length(); i++) {
806 NativePointerInfo info = _native_pointers->at(i);
807 oop src_obj = info._src_obj;
808 int field_offset = info._field_offset;
809 HeapShared::CachedOopInfo* p = HeapShared::get_cached_oop_info(src_obj);
810 // requested_field_addr = the address of this field in the requested space
811 oop requested_obj = requested_obj_from_buffer_offset(p->buffer_offset());
812 Metadata** requested_field_addr = (Metadata**)(cast_from_oop<address>(requested_obj) + field_offset);
813 assert(bottom <= requested_field_addr && requested_field_addr < top, "range check");
814
815 // Mark this field in the bitmap
816 BitMap::idx_t idx = requested_field_addr - bottom;
817 heap_info->ptrmap()->set_bit(idx);
818 num_non_null_ptrs ++;
819 max_idx = MAX2(max_idx, idx);
820
821 // Set the native pointer to the requested address of the metadata (at runtime, the metadata will have
822 // this address if the RO/RW regions are mapped at the default location).
823
824 Metadata** buffered_field_addr = requested_addr_to_buffered_addr(requested_field_addr);
825 Metadata* native_ptr = *buffered_field_addr;
826 guarantee(native_ptr != nullptr, "sanity");
827
828 if (RegeneratedClasses::has_been_regenerated(native_ptr)) {
829 native_ptr = RegeneratedClasses::get_regenerated_object(native_ptr);
830 }
831
832 guarantee(ArchiveBuilder::current()->has_been_archived((address)native_ptr),
833 "Metadata %p should have been archived", native_ptr);
834
835 if (RegeneratedClasses::has_been_regenerated((address)native_ptr)) {
836 native_ptr = (Metadata*)RegeneratedClasses::get_regenerated_object((address)native_ptr);
837 }
838
839 address buffered_native_ptr = ArchiveBuilder::current()->get_buffered_addr((address)native_ptr);
840 address requested_native_ptr = ArchiveBuilder::current()->to_requested(buffered_native_ptr);
841 *buffered_field_addr = (Metadata*)requested_native_ptr;
842 }
843
844 heap_info->ptrmap()->resize(max_idx + 1);
845 log_info(aot, heap)("calculate_ptrmap: marked %d non-null native pointers for heap region (%zu bits)",
846 num_non_null_ptrs, size_t(heap_info->ptrmap()->size()));
847 }
848
849 #endif // INCLUDE_CDS_JAVA_HEAP