1 /*
2 * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "cds/archiveHeapWriter.hpp"
27 #include "cds/filemap.hpp"
28 #include "cds/heapShared.hpp"
29 #include "gc/shared/collectedHeap.hpp"
30 #include "memory/iterator.inline.hpp"
31 #include "memory/oopFactory.hpp"
32 #include "memory/universe.hpp"
33 #include "oops/compressedOops.hpp"
34 #include "oops/oop.inline.hpp"
35 #include "oops/objArrayOop.inline.hpp"
36 #include "oops/oopHandle.inline.hpp"
37 #include "oops/typeArrayKlass.hpp"
38 #include "oops/typeArrayOop.hpp"
39 #include "runtime/java.hpp"
40 #include "runtime/mutexLocker.hpp"
41 #include "utilities/bitMap.inline.hpp"
42
43 #if INCLUDE_G1GC
44 #include "gc/g1/g1CollectedHeap.hpp"
45 #include "gc/g1/heapRegion.hpp"
46 #endif
47
48 #if INCLUDE_CDS_JAVA_HEAP
49
50 GrowableArrayCHeap<u1, mtClassShared>* ArchiveHeapWriter::_buffer;
51
52 // The following are offsets from buffer_bottom()
53 size_t ArchiveHeapWriter::_buffer_used;
54 size_t ArchiveHeapWriter::_heap_roots_bottom_offset;
55
56 size_t ArchiveHeapWriter::_heap_roots_word_size;
57
58 address ArchiveHeapWriter::_requested_bottom;
59 address ArchiveHeapWriter::_requested_top;
60
61 GrowableArrayCHeap<ArchiveHeapWriter::NativePointerInfo, mtClassShared>* ArchiveHeapWriter::_native_pointers;
62 GrowableArrayCHeap<oop, mtClassShared>* ArchiveHeapWriter::_source_objs;
63
64 ArchiveHeapWriter::BufferOffsetToSourceObjectTable*
65 ArchiveHeapWriter::_buffer_offset_to_source_obj_table = nullptr;
66
67 void ArchiveHeapWriter::init() {
68 if (HeapShared::can_write()) {
69 Universe::heap()->collect(GCCause::_java_lang_system_gc);
70
71 _buffer_offset_to_source_obj_table = new BufferOffsetToSourceObjectTable();
72
73 _requested_bottom = nullptr;
74 _requested_top = nullptr;
75
76 _native_pointers = new GrowableArrayCHeap<NativePointerInfo, mtClassShared>(2048);
77 _source_objs = new GrowableArrayCHeap<oop, mtClassShared>(10000);
78
79 guarantee(UseG1GC, "implementation limitation");
80 guarantee(MIN_GC_REGION_ALIGNMENT <= /*G1*/HeapRegion::min_region_size_in_words() * HeapWordSize, "must be");
81 }
82 }
83
84 void ArchiveHeapWriter::add_source_obj(oop src_obj) {
85 _source_objs->append(src_obj);
86 }
87
88 void ArchiveHeapWriter::write(GrowableArrayCHeap<oop, mtClassShared>* roots,
89 ArchiveHeapInfo* heap_info) {
90 assert(HeapShared::can_write(), "sanity");
91 allocate_buffer();
92 copy_source_objs_to_buffer(roots);
93 set_requested_address(heap_info);
94 relocate_embedded_oops(roots, heap_info);
95 }
96
97 bool ArchiveHeapWriter::is_too_large_to_archive(oop o) {
98 return is_too_large_to_archive(o->size());
99 }
100
101 bool ArchiveHeapWriter::is_string_too_large_to_archive(oop string) {
102 typeArrayOop value = java_lang_String::value_no_keepalive(string);
103 return is_too_large_to_archive(value);
104 }
105
106 bool ArchiveHeapWriter::is_too_large_to_archive(size_t size) {
107 assert(size > 0, "no zero-size object");
108 assert(size * HeapWordSize > size, "no overflow");
109 static_assert(MIN_GC_REGION_ALIGNMENT > 0, "must be positive");
110
111 size_t byte_size = size * HeapWordSize;
112 if (byte_size > size_t(MIN_GC_REGION_ALIGNMENT)) {
113 return true;
114 } else {
115 return false;
116 }
117 }
118
119 // Various lookup functions between source_obj, buffered_obj and requested_obj
120 bool ArchiveHeapWriter::is_in_requested_range(oop o) {
121 assert(_requested_bottom != nullptr, "do not call before _requested_bottom is initialized");
122 address a = cast_from_oop<address>(o);
123 return (_requested_bottom <= a && a < _requested_top);
124 }
125
126 oop ArchiveHeapWriter::requested_obj_from_buffer_offset(size_t offset) {
127 oop req_obj = cast_to_oop(_requested_bottom + offset);
128 assert(is_in_requested_range(req_obj), "must be");
129 return req_obj;
130 }
131
132 oop ArchiveHeapWriter::source_obj_to_requested_obj(oop src_obj) {
133 assert(DumpSharedSpaces, "dump-time only");
134 HeapShared::CachedOopInfo* p = HeapShared::archived_object_cache()->get(src_obj);
135 if (p != nullptr) {
136 return requested_obj_from_buffer_offset(p->buffer_offset());
137 } else {
138 return nullptr;
139 }
140 }
141
142 oop ArchiveHeapWriter::buffered_addr_to_source_obj(address buffered_addr) {
143 oop* p = _buffer_offset_to_source_obj_table->get(buffered_address_to_offset(buffered_addr));
144 if (p != nullptr) {
145 return *p;
146 } else {
147 return nullptr;
148 }
149 }
150
151 address ArchiveHeapWriter::buffered_addr_to_requested_addr(address buffered_addr) {
152 return _requested_bottom + buffered_address_to_offset(buffered_addr);
153 }
154
155 oop ArchiveHeapWriter::heap_roots_requested_address() {
156 return cast_to_oop(_requested_bottom + _heap_roots_bottom_offset);
157 }
158
159 address ArchiveHeapWriter::requested_address() {
160 assert(_buffer != nullptr, "must be initialized");
161 return _requested_bottom;
162 }
163
164 void ArchiveHeapWriter::allocate_buffer() {
165 int initial_buffer_size = 100000;
166 _buffer = new GrowableArrayCHeap<u1, mtClassShared>(initial_buffer_size);
167 _buffer_used = 0;
168 ensure_buffer_space(1); // so that buffer_bottom() works
169 }
170
171 void ArchiveHeapWriter::ensure_buffer_space(size_t min_bytes) {
172 // We usually have very small heaps. If we get a huge one it's probably caused by a bug.
173 guarantee(min_bytes <= max_jint, "we dont support archiving more than 2G of objects");
174 _buffer->at_grow(to_array_index(min_bytes));
175 }
176
177 void ArchiveHeapWriter::copy_roots_to_buffer(GrowableArrayCHeap<oop, mtClassShared>* roots) {
178 Klass* k = Universe::objectArrayKlassObj(); // already relocated to point to archived klass
179 int length = roots->length();
180 _heap_roots_word_size = objArrayOopDesc::object_size(length);
181 size_t byte_size = _heap_roots_word_size * HeapWordSize;
182 if (byte_size >= MIN_GC_REGION_ALIGNMENT) {
183 log_error(cds, heap)("roots array is too large. Please reduce the number of classes");
184 vm_exit(1);
185 }
186
187 maybe_fill_gc_region_gap(byte_size);
188
189 size_t new_used = _buffer_used + byte_size;
190 ensure_buffer_space(new_used);
191
192 HeapWord* mem = offset_to_buffered_address<HeapWord*>(_buffer_used);
193 memset(mem, 0, byte_size);
194 {
195 // This is copied from MemAllocator::finish
196 oopDesc::set_mark(mem, markWord::prototype());
197 oopDesc::release_set_klass(mem, k);
198 }
199 {
200 // This is copied from ObjArrayAllocator::initialize
201 arrayOopDesc::set_length(mem, length);
202 }
203
204 objArrayOop arrayOop = objArrayOop(cast_to_oop(mem));
205 for (int i = 0; i < length; i++) {
206 // Do not use arrayOop->obj_at_put(i, o) as arrayOop is outside of the real heap!
207 oop o = roots->at(i);
208 if (UseCompressedOops) {
209 * arrayOop->obj_at_addr<narrowOop>(i) = CompressedOops::encode(o);
210 } else {
211 * arrayOop->obj_at_addr<oop>(i) = o;
212 }
213 }
214 log_info(cds, heap)("archived obj roots[%d] = " SIZE_FORMAT " bytes, klass = %p, obj = %p", length, byte_size, k, mem);
215
216 _heap_roots_bottom_offset = _buffer_used;
217 _buffer_used = new_used;
218 }
219
220 void ArchiveHeapWriter::copy_source_objs_to_buffer(GrowableArrayCHeap<oop, mtClassShared>* roots) {
221 for (int i = 0; i < _source_objs->length(); i++) {
222 oop src_obj = _source_objs->at(i);
223 HeapShared::CachedOopInfo* info = HeapShared::archived_object_cache()->get(src_obj);
224 assert(info != nullptr, "must be");
225 size_t buffer_offset = copy_one_source_obj_to_buffer(src_obj);
226 info->set_buffer_offset(buffer_offset);
227
228 _buffer_offset_to_source_obj_table->put(buffer_offset, src_obj);
229 }
230
231 copy_roots_to_buffer(roots);
232
233 log_info(cds)("Size of heap region = " SIZE_FORMAT " bytes, %d objects, %d roots",
234 _buffer_used, _source_objs->length() + 1, roots->length());
235 }
236
237 size_t ArchiveHeapWriter::filler_array_byte_size(int length) {
238 size_t byte_size = objArrayOopDesc::object_size(length) * HeapWordSize;
239 return byte_size;
240 }
241
242 int ArchiveHeapWriter::filler_array_length(size_t fill_bytes) {
243 assert(is_object_aligned(fill_bytes), "must be");
244 size_t elemSize = (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop));
245
246 int initial_length = to_array_length(fill_bytes / elemSize);
247 for (int length = initial_length; length >= 0; length --) {
248 size_t array_byte_size = filler_array_byte_size(length);
249 if (array_byte_size == fill_bytes) {
250 return length;
251 }
252 }
253
254 ShouldNotReachHere();
255 return -1;
256 }
257
258 void ArchiveHeapWriter::init_filler_array_at_buffer_top(int array_length, size_t fill_bytes) {
259 assert(UseCompressedClassPointers, "Archived heap only supported for compressed klasses");
260 Klass* oak = Universe::objectArrayKlassObj(); // already relocated to point to archived klass
261 HeapWord* mem = offset_to_buffered_address<HeapWord*>(_buffer_used);
262 memset(mem, 0, fill_bytes);
263 oopDesc::set_mark(mem, markWord::prototype());
264 narrowKlass nk = ArchiveBuilder::current()->get_requested_narrow_klass(oak);
265 cast_to_oop(mem)->set_narrow_klass(nk);
266 arrayOopDesc::set_length(mem, array_length);
267 }
268
269 void ArchiveHeapWriter::maybe_fill_gc_region_gap(size_t required_byte_size) {
270 // We fill only with arrays (so we don't need to use a single HeapWord filler if the
271 // leftover space is smaller than a zero-sized array object). Therefore, we need to
272 // make sure there's enough space of min_filler_byte_size in the current region after
273 // required_byte_size has been allocated. If not, fill the remainder of the current
274 // region.
275 size_t min_filler_byte_size = filler_array_byte_size(0);
276 size_t new_used = _buffer_used + required_byte_size + min_filler_byte_size;
277
278 const size_t cur_min_region_bottom = align_down(_buffer_used, MIN_GC_REGION_ALIGNMENT);
279 const size_t next_min_region_bottom = align_down(new_used, MIN_GC_REGION_ALIGNMENT);
280
281 if (cur_min_region_bottom != next_min_region_bottom) {
282 // Make sure that no objects span across MIN_GC_REGION_ALIGNMENT. This way
283 // we can map the region in any region-based collector.
284 assert(next_min_region_bottom > cur_min_region_bottom, "must be");
285 assert(next_min_region_bottom - cur_min_region_bottom == MIN_GC_REGION_ALIGNMENT,
286 "no buffered object can be larger than %d bytes", MIN_GC_REGION_ALIGNMENT);
287
288 const size_t filler_end = next_min_region_bottom;
289 const size_t fill_bytes = filler_end - _buffer_used;
290 assert(fill_bytes > 0, "must be");
291 ensure_buffer_space(filler_end);
292
293 int array_length = filler_array_length(fill_bytes);
294 log_info(cds, heap)("Inserting filler obj array of %d elements (" SIZE_FORMAT " bytes total) @ buffer offset " SIZE_FORMAT,
295 array_length, fill_bytes, _buffer_used);
296 init_filler_array_at_buffer_top(array_length, fill_bytes);
297
298 _buffer_used = filler_end;
299 }
300 }
301
302 size_t ArchiveHeapWriter::copy_one_source_obj_to_buffer(oop src_obj) {
303 assert(!is_too_large_to_archive(src_obj), "already checked");
304 size_t byte_size = src_obj->size() * HeapWordSize;
305 assert(byte_size > 0, "no zero-size objects");
306
307 // For region-based collectors such as G1, the archive heap may be mapped into
308 // multiple regions. We need to make sure that we don't have an object that can possible
309 // span across two regions.
310 maybe_fill_gc_region_gap(byte_size);
311
312 size_t new_used = _buffer_used + byte_size;
313 assert(new_used > _buffer_used, "no wrap around");
314
315 size_t cur_min_region_bottom = align_down(_buffer_used, MIN_GC_REGION_ALIGNMENT);
316 size_t next_min_region_bottom = align_down(new_used, MIN_GC_REGION_ALIGNMENT);
317 assert(cur_min_region_bottom == next_min_region_bottom, "no object should cross minimal GC region boundaries");
318
319 ensure_buffer_space(new_used);
320
321 address from = cast_from_oop<address>(src_obj);
322 address to = offset_to_buffered_address<address>(_buffer_used);
323 assert(is_object_aligned(_buffer_used), "sanity");
324 assert(is_object_aligned(byte_size), "sanity");
325 memcpy(to, from, byte_size);
326
327 size_t buffered_obj_offset = _buffer_used;
328 _buffer_used = new_used;
329
330 return buffered_obj_offset;
331 }
332
333 void ArchiveHeapWriter::set_requested_address(ArchiveHeapInfo* info) {
334 assert(!info->is_used(), "only set once");
335 assert(UseG1GC, "must be");
336 address heap_end = (address)G1CollectedHeap::heap()->reserved().end();
337 log_info(cds, heap)("Heap end = %p", heap_end);
338
339 size_t heap_region_byte_size = _buffer_used;
340 assert(heap_region_byte_size > 0, "must archived at least one object!");
341
342 _requested_bottom = align_down(heap_end - heap_region_byte_size, HeapRegion::GrainBytes);
343 assert(is_aligned(_requested_bottom, HeapRegion::GrainBytes), "sanity");
344
345 _requested_top = _requested_bottom + _buffer_used;
346
347 info->set_memregion(MemRegion(offset_to_buffered_address<HeapWord*>(0),
348 offset_to_buffered_address<HeapWord*>(_buffer_used)));
349 }
350
351 // Oop relocation
352
353 template <typename T> T* ArchiveHeapWriter::requested_addr_to_buffered_addr(T* p) {
354 assert(is_in_requested_range(cast_to_oop(p)), "must be");
355
356 address addr = address(p);
357 assert(addr >= _requested_bottom, "must be");
358 size_t offset = addr - _requested_bottom;
359 return offset_to_buffered_address<T*>(offset);
360 }
361
362 template <typename T> oop ArchiveHeapWriter::load_source_oop_from_buffer(T* buffered_addr) {
363 oop o = load_oop_from_buffer(buffered_addr);
364 assert(!in_buffer(cast_from_oop<address>(o)), "must point to source oop");
365 return o;
366 }
367
368 template <typename T> void ArchiveHeapWriter::store_requested_oop_in_buffer(T* buffered_addr,
369 oop request_oop) {
370 assert(is_in_requested_range(request_oop), "must be");
371 store_oop_in_buffer(buffered_addr, request_oop);
372 }
373
374 void ArchiveHeapWriter::store_oop_in_buffer(oop* buffered_addr, oop requested_obj) {
375 // Make heap content deterministic. See comments inside HeapShared::to_requested_address.
376 *buffered_addr = HeapShared::to_requested_address(requested_obj);
377 }
378
379 void ArchiveHeapWriter::store_oop_in_buffer(narrowOop* buffered_addr, oop requested_obj) {
380 // Note: HeapShared::to_requested_address() is not necessary because
381 // the heap always starts at a deterministic address with UseCompressedOops==true.
382 narrowOop val = CompressedOops::encode_not_null(requested_obj);
383 *buffered_addr = val;
384 }
385
386 oop ArchiveHeapWriter::load_oop_from_buffer(oop* buffered_addr) {
387 return *buffered_addr;
388 }
389
390 oop ArchiveHeapWriter::load_oop_from_buffer(narrowOop* buffered_addr) {
391 return CompressedOops::decode(*buffered_addr);
392 }
393
394 template <typename T> void ArchiveHeapWriter::relocate_field_in_buffer(T* field_addr_in_buffer, CHeapBitMap* oopmap) {
395 oop source_referent = load_source_oop_from_buffer<T>(field_addr_in_buffer);
396 if (!CompressedOops::is_null(source_referent)) {
397 oop request_referent = source_obj_to_requested_obj(source_referent);
398 store_requested_oop_in_buffer<T>(field_addr_in_buffer, request_referent);
399 mark_oop_pointer<T>(field_addr_in_buffer, oopmap);
400 }
401 }
402
403 template <typename T> void ArchiveHeapWriter::mark_oop_pointer(T* buffered_addr, CHeapBitMap* oopmap) {
404 T* request_p = (T*)(buffered_addr_to_requested_addr((address)buffered_addr));
405 address requested_region_bottom;
406
407 assert(request_p >= (T*)_requested_bottom, "sanity");
408 assert(request_p < (T*)_requested_top, "sanity");
409 requested_region_bottom = _requested_bottom;
410
411 // Mark the pointer in the oopmap
412 T* region_bottom = (T*)requested_region_bottom;
413 assert(request_p >= region_bottom, "must be");
414 BitMap::idx_t idx = request_p - region_bottom;
415 assert(idx < oopmap->size(), "overflow");
416 oopmap->set_bit(idx);
417 }
418
419 void ArchiveHeapWriter::update_header_for_requested_obj(oop requested_obj, oop src_obj, Klass* src_klass) {
420 assert(UseCompressedClassPointers, "Archived heap only supported for compressed klasses");
421 narrowKlass nk = ArchiveBuilder::current()->get_requested_narrow_klass(src_klass);
422 address buffered_addr = requested_addr_to_buffered_addr(cast_from_oop<address>(requested_obj));
423
424 oop fake_oop = cast_to_oop(buffered_addr);
425 fake_oop->set_narrow_klass(nk);
426
427 // We need to retain the identity_hash, because it may have been used by some hashtables
428 // in the shared heap. This also has the side effect of pre-initializing the
429 // identity_hash for all shared objects, so they are less likely to be written
430 // into during run time, increasing the potential of memory sharing.
431 if (src_obj != nullptr) {
432 int src_hash = src_obj->identity_hash();
433 fake_oop->set_mark(markWord::prototype().copy_set_hash(src_hash));
434 assert(fake_oop->mark().is_unlocked(), "sanity");
435
436 DEBUG_ONLY(int archived_hash = fake_oop->identity_hash());
437 assert(src_hash == archived_hash, "Different hash codes: original %x, archived %x", src_hash, archived_hash);
438 }
439 }
440
441 // Relocate an element in the buffered copy of HeapShared::roots()
442 template <typename T> void ArchiveHeapWriter::relocate_root_at(oop requested_roots, int index, CHeapBitMap* oopmap) {
443 size_t offset = (size_t)((objArrayOop)requested_roots)->obj_at_offset<T>(index);
444 relocate_field_in_buffer<T>((T*)(buffered_heap_roots_addr() + offset), oopmap);
445 }
446
447 class ArchiveHeapWriter::EmbeddedOopRelocator: public BasicOopIterateClosure {
448 oop _src_obj;
449 address _buffered_obj;
450 CHeapBitMap* _oopmap;
451
452 public:
453 EmbeddedOopRelocator(oop src_obj, address buffered_obj, CHeapBitMap* oopmap) :
454 _src_obj(src_obj), _buffered_obj(buffered_obj), _oopmap(oopmap) {}
455
456 void do_oop(narrowOop *p) { EmbeddedOopRelocator::do_oop_work(p); }
457 void do_oop( oop *p) { EmbeddedOopRelocator::do_oop_work(p); }
458
459 private:
460 template <class T> void do_oop_work(T *p) {
461 size_t field_offset = pointer_delta(p, _src_obj, sizeof(char));
462 ArchiveHeapWriter::relocate_field_in_buffer<T>((T*)(_buffered_obj + field_offset), _oopmap);
463 }
464 };
465
466 // Update all oop fields embedded in the buffered objects
467 void ArchiveHeapWriter::relocate_embedded_oops(GrowableArrayCHeap<oop, mtClassShared>* roots,
468 ArchiveHeapInfo* heap_info) {
469 size_t oopmap_unit = (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop));
470 size_t heap_region_byte_size = _buffer_used;
471 heap_info->oopmap()->resize(heap_region_byte_size / oopmap_unit);
472
473 auto iterator = [&] (oop src_obj, HeapShared::CachedOopInfo& info) {
474 oop requested_obj = requested_obj_from_buffer_offset(info.buffer_offset());
475 update_header_for_requested_obj(requested_obj, src_obj, src_obj->klass());
476 address buffered_obj = offset_to_buffered_address<address>(info.buffer_offset());
477 EmbeddedOopRelocator relocator(src_obj, buffered_obj, heap_info->oopmap());
478 src_obj->oop_iterate(&relocator);
479 };
480 HeapShared::archived_object_cache()->iterate_all(iterator);
481
482 // Relocate HeapShared::roots(), which is created in copy_roots_to_buffer() and
483 // doesn't have a corresponding src_obj, so we can't use EmbeddedOopRelocator on it.
484 oop requested_roots = requested_obj_from_buffer_offset(_heap_roots_bottom_offset);
485 update_header_for_requested_obj(requested_roots, nullptr, Universe::objectArrayKlassObj());
486 int length = roots != nullptr ? roots->length() : 0;
487 for (int i = 0; i < length; i++) {
488 if (UseCompressedOops) {
489 relocate_root_at<narrowOop>(requested_roots, i, heap_info->oopmap());
490 } else {
491 relocate_root_at<oop>(requested_roots, i, heap_info->oopmap());
492 }
493 }
494
495 compute_ptrmap(heap_info);
496 }
497
498 void ArchiveHeapWriter::mark_native_pointer(oop src_obj, int field_offset) {
499 Metadata* ptr = src_obj->metadata_field_acquire(field_offset);
500 if (ptr != nullptr) {
501 NativePointerInfo info;
502 info._src_obj = src_obj;
503 info._field_offset = field_offset;
504 _native_pointers->append(info);
505 }
506 }
507
508 void ArchiveHeapWriter::compute_ptrmap(ArchiveHeapInfo* heap_info) {
509 int num_non_null_ptrs = 0;
510 Metadata** bottom = (Metadata**) _requested_bottom;
511 Metadata** top = (Metadata**) _requested_top; // exclusive
512 heap_info->ptrmap()->resize(top - bottom);
513
514 BitMap::idx_t max_idx = 32; // paranoid - don't make it too small
515 for (int i = 0; i < _native_pointers->length(); i++) {
516 NativePointerInfo info = _native_pointers->at(i);
517 oop src_obj = info._src_obj;
518 int field_offset = info._field_offset;
519 HeapShared::CachedOopInfo* p = HeapShared::archived_object_cache()->get(src_obj);
520 // requested_field_addr = the address of this field in the requested space
521 oop requested_obj = requested_obj_from_buffer_offset(p->buffer_offset());
522 Metadata** requested_field_addr = (Metadata**)(cast_from_oop<address>(requested_obj) + field_offset);
523 assert(bottom <= requested_field_addr && requested_field_addr < top, "range check");
524
525 // Mark this field in the bitmap
526 BitMap::idx_t idx = requested_field_addr - bottom;
527 heap_info->ptrmap()->set_bit(idx);
528 num_non_null_ptrs ++;
529 max_idx = MAX2(max_idx, idx);
530
531 // Set the native pointer to the requested address of the metadata (at runtime, the metadata will have
532 // this address if the RO/RW regions are mapped at the default location).
533
534 Metadata** buffered_field_addr = requested_addr_to_buffered_addr(requested_field_addr);
535 Metadata* native_ptr = *buffered_field_addr;
536 assert(native_ptr != nullptr, "sanity");
537
538 address buffered_native_ptr = ArchiveBuilder::current()->get_buffered_addr((address)native_ptr);
539 address requested_native_ptr = ArchiveBuilder::current()->to_requested(buffered_native_ptr);
540 *buffered_field_addr = (Metadata*)requested_native_ptr;
541 }
542
543 heap_info->ptrmap()->resize(max_idx + 1);
544 log_info(cds, heap)("calculate_ptrmap: marked %d non-null native pointers for heap region (" SIZE_FORMAT " bits)",
545 num_non_null_ptrs, size_t(heap_info->ptrmap()->size()));
546 }
547
548 #endif // INCLUDE_CDS_JAVA_HEAP