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