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