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