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 = nullptr;
51
52 // The following are offsets from buffer_bottom()
53 size_t ArchiveHeapWriter::_buffer_used;
54 size_t ArchiveHeapWriter::_heap_roots_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
68 typedef ResourceHashtable<address, size_t,
69 127, // prime number
70 AnyObj::C_HEAP,
71 mtClassShared> FillersTable;
72 static FillersTable* _fillers;
73
74 void ArchiveHeapWriter::init() {
75 if (HeapShared::can_write()) {
76 Universe::heap()->collect(GCCause::_java_lang_system_gc);
77
78 _buffer_offset_to_source_obj_table = new BufferOffsetToSourceObjectTable();
79 _fillers = new FillersTable();
80 _requested_bottom = nullptr;
81 _requested_top = nullptr;
82
83 _native_pointers = new GrowableArrayCHeap<NativePointerInfo, mtClassShared>(2048);
84 _source_objs = new GrowableArrayCHeap<oop, mtClassShared>(10000);
85
86 guarantee(UseG1GC, "implementation limitation");
87 guarantee(MIN_GC_REGION_ALIGNMENT <= /*G1*/HeapRegion::min_region_size_in_words() * HeapWordSize, "must be");
88 }
89 }
90
91 void ArchiveHeapWriter::add_source_obj(oop src_obj) {
92 _source_objs->append(src_obj);
93 }
94
95 void ArchiveHeapWriter::write(GrowableArrayCHeap<oop, mtClassShared>* roots,
96 ArchiveHeapInfo* heap_info) {
97 assert(HeapShared::can_write(), "sanity");
98 allocate_buffer();
99 copy_source_objs_to_buffer(roots);
100 set_requested_address(heap_info);
101 relocate_embedded_oops(roots, heap_info);
102 }
103
104 bool ArchiveHeapWriter::is_too_large_to_archive(oop o) {
105 return is_too_large_to_archive(o->size());
106 }
107
108 bool ArchiveHeapWriter::is_string_too_large_to_archive(oop string) {
109 typeArrayOop value = java_lang_String::value_no_keepalive(string);
110 return is_too_large_to_archive(value);
111 }
112
113 bool ArchiveHeapWriter::is_too_large_to_archive(size_t size) {
114 assert(size > 0, "no zero-size object");
115 assert(size * HeapWordSize > size, "no overflow");
116 static_assert(MIN_GC_REGION_ALIGNMENT > 0, "must be positive");
117
118 size_t byte_size = size * HeapWordSize;
119 if (byte_size > size_t(MIN_GC_REGION_ALIGNMENT)) {
120 return true;
121 } else {
122 return false;
123 }
124 }
125
126 // Various lookup functions between source_obj, buffered_obj and requested_obj
127 bool ArchiveHeapWriter::is_in_requested_range(oop o) {
128 assert(_requested_bottom != nullptr, "do not call before _requested_bottom is initialized");
129 address a = cast_from_oop<address>(o);
130 return (_requested_bottom <= a && a < _requested_top);
131 }
132
133 oop ArchiveHeapWriter::requested_obj_from_buffer_offset(size_t offset) {
134 oop req_obj = cast_to_oop(_requested_bottom + offset);
135 assert(is_in_requested_range(req_obj), "must be");
136 return req_obj;
137 }
138
139 oop ArchiveHeapWriter::source_obj_to_requested_obj(oop src_obj) {
140 assert(DumpSharedSpaces, "dump-time only");
141 HeapShared::CachedOopInfo* p = HeapShared::archived_object_cache()->get(src_obj);
142 if (p != nullptr) {
143 return requested_obj_from_buffer_offset(p->buffer_offset());
144 } else {
145 return nullptr;
146 }
147 }
148
149 oop ArchiveHeapWriter::buffered_addr_to_source_obj(address buffered_addr) {
150 oop* p = _buffer_offset_to_source_obj_table->get(buffered_address_to_offset(buffered_addr));
151 if (p != nullptr) {
152 return *p;
153 } else {
154 return nullptr;
155 }
156 }
157
158 address ArchiveHeapWriter::buffered_addr_to_requested_addr(address buffered_addr) {
159 return _requested_bottom + buffered_address_to_offset(buffered_addr);
160 }
161
162 oop ArchiveHeapWriter::heap_roots_requested_address() {
163 return cast_to_oop(_requested_bottom + _heap_roots_offset);
164 }
165
166 address ArchiveHeapWriter::requested_address() {
167 assert(_buffer != nullptr, "must be initialized");
168 return _requested_bottom;
169 }
170
171 void ArchiveHeapWriter::allocate_buffer() {
172 int initial_buffer_size = 100000;
173 _buffer = new GrowableArrayCHeap<u1, mtClassShared>(initial_buffer_size);
174 _buffer_used = 0;
175 ensure_buffer_space(1); // so that buffer_bottom() works
176 }
177
178 void ArchiveHeapWriter::ensure_buffer_space(size_t min_bytes) {
179 // We usually have very small heaps. If we get a huge one it's probably caused by a bug.
180 guarantee(min_bytes <= max_jint, "we dont support archiving more than 2G of objects");
181 _buffer->at_grow(to_array_index(min_bytes));
182 }
183
184 void ArchiveHeapWriter::copy_roots_to_buffer(GrowableArrayCHeap<oop, mtClassShared>* roots) {
185 Klass* k = Universe::objectArrayKlassObj(); // already relocated to point to archived klass
186 int length = roots->length();
187 _heap_roots_word_size = objArrayOopDesc::object_size(length);
188 size_t byte_size = _heap_roots_word_size * HeapWordSize;
189 if (byte_size >= MIN_GC_REGION_ALIGNMENT) {
190 log_error(cds, heap)("roots array is too large. Please reduce the number of classes");
191 vm_exit(1);
192 }
193
194 maybe_fill_gc_region_gap(byte_size);
195
196 size_t new_used = _buffer_used + byte_size;
197 ensure_buffer_space(new_used);
198
199 HeapWord* mem = offset_to_buffered_address<HeapWord*>(_buffer_used);
200 memset(mem, 0, byte_size);
201 {
202 // This is copied from MemAllocator::finish
203 oopDesc::set_mark(mem, markWord::prototype());
204 oopDesc::release_set_klass(mem, k);
205 }
206 {
207 // This is copied from ObjArrayAllocator::initialize
208 arrayOopDesc::set_length(mem, length);
209 }
210
211 objArrayOop arrayOop = objArrayOop(cast_to_oop(mem));
212 for (int i = 0; i < length; i++) {
213 // Do not use arrayOop->obj_at_put(i, o) as arrayOop is outside of the real heap!
214 oop o = roots->at(i);
215 if (UseCompressedOops) {
216 * arrayOop->obj_at_addr<narrowOop>(i) = CompressedOops::encode(o);
217 } else {
218 * arrayOop->obj_at_addr<oop>(i) = o;
219 }
220 }
221 log_info(cds, heap)("archived obj roots[%d] = " SIZE_FORMAT " bytes, klass = %p, obj = %p", length, byte_size, k, mem);
222
223 _heap_roots_offset = _buffer_used;
224 _buffer_used = new_used;
225 }
226
227 void ArchiveHeapWriter::copy_source_objs_to_buffer(GrowableArrayCHeap<oop, mtClassShared>* roots) {
228 for (int i = 0; i < _source_objs->length(); i++) {
229 oop src_obj = _source_objs->at(i);
230 HeapShared::CachedOopInfo* info = HeapShared::archived_object_cache()->get(src_obj);
231 assert(info != nullptr, "must be");
232 size_t buffer_offset = copy_one_source_obj_to_buffer(src_obj);
233 info->set_buffer_offset(buffer_offset);
234
235 _buffer_offset_to_source_obj_table->put(buffer_offset, src_obj);
236 }
237
238 copy_roots_to_buffer(roots);
239
240 log_info(cds)("Size of heap region = " SIZE_FORMAT " bytes, %d objects, %d roots",
241 _buffer_used, _source_objs->length() + 1, roots->length());
242 }
243
244 size_t ArchiveHeapWriter::filler_array_byte_size(int length) {
245 size_t byte_size = objArrayOopDesc::object_size(length) * HeapWordSize;
246 return byte_size;
247 }
248
249 int ArchiveHeapWriter::filler_array_length(size_t fill_bytes) {
250 assert(is_object_aligned(fill_bytes), "must be");
251 size_t elemSize = (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop));
252
253 int initial_length = to_array_length(fill_bytes / elemSize);
254 for (int length = initial_length; length >= 0; length --) {
255 size_t array_byte_size = filler_array_byte_size(length);
256 if (array_byte_size == fill_bytes) {
257 return length;
258 }
259 }
260
261 ShouldNotReachHere();
262 return -1;
263 }
264
265 HeapWord* ArchiveHeapWriter::init_filler_array_at_buffer_top(int array_length, size_t fill_bytes) {
266 assert(UseCompressedClassPointers, "Archived heap only supported for compressed klasses");
267 Klass* oak = Universe::objectArrayKlassObj(); // already relocated to point to archived klass
268 HeapWord* mem = offset_to_buffered_address<HeapWord*>(_buffer_used);
269 memset(mem, 0, fill_bytes);
270 oopDesc::set_mark(mem, markWord::prototype());
271 narrowKlass nk = ArchiveBuilder::current()->get_requested_narrow_klass(oak);
272 cast_to_oop(mem)->set_narrow_klass(nk);
273 arrayOopDesc::set_length(mem, array_length);
274 return mem;
275 }
276
277 void ArchiveHeapWriter::maybe_fill_gc_region_gap(size_t required_byte_size) {
278 // We fill only with arrays (so we don't need to use a single HeapWord filler if the
279 // leftover space is smaller than a zero-sized array object). Therefore, we need to
280 // make sure there's enough space of min_filler_byte_size in the current region after
281 // required_byte_size has been allocated. If not, fill the remainder of the current
282 // region.
283 size_t min_filler_byte_size = filler_array_byte_size(0);
284 size_t new_used = _buffer_used + required_byte_size + min_filler_byte_size;
285
286 const size_t cur_min_region_bottom = align_down(_buffer_used, MIN_GC_REGION_ALIGNMENT);
287 const size_t next_min_region_bottom = align_down(new_used, MIN_GC_REGION_ALIGNMENT);
288
289 if (cur_min_region_bottom != next_min_region_bottom) {
290 // Make sure that no objects span across MIN_GC_REGION_ALIGNMENT. This way
291 // we can map the region in any region-based collector.
292 assert(next_min_region_bottom > cur_min_region_bottom, "must be");
293 assert(next_min_region_bottom - cur_min_region_bottom == MIN_GC_REGION_ALIGNMENT,
294 "no buffered object can be larger than %d bytes", MIN_GC_REGION_ALIGNMENT);
295
296 const size_t filler_end = next_min_region_bottom;
297 const size_t fill_bytes = filler_end - _buffer_used;
298 assert(fill_bytes > 0, "must be");
299 ensure_buffer_space(filler_end);
300
301 int array_length = filler_array_length(fill_bytes);
302 log_info(cds, heap)("Inserting filler obj array of %d elements (" SIZE_FORMAT " bytes total) @ buffer offset " SIZE_FORMAT,
303 array_length, fill_bytes, _buffer_used);
304 HeapWord* filler = init_filler_array_at_buffer_top(array_length, fill_bytes);
305 _buffer_used = filler_end;
306 _fillers->put((address)filler, fill_bytes);
307 }
308 }
309
310 size_t ArchiveHeapWriter::get_filler_size_at(address buffered_addr) {
311 size_t* p = _fillers->get(buffered_addr);
312 if (p != nullptr) {
313 assert(*p > 0, "filler must be larger than zero bytes");
314 return *p;
315 } else {
316 return 0; // buffered_addr is not a filler
317 }
318 }
319
320 size_t ArchiveHeapWriter::copy_one_source_obj_to_buffer(oop src_obj) {
321 assert(!is_too_large_to_archive(src_obj), "already checked");
322 size_t byte_size = src_obj->size() * HeapWordSize;
323 assert(byte_size > 0, "no zero-size objects");
324
325 // For region-based collectors such as G1, the archive heap may be mapped into
326 // multiple regions. We need to make sure that we don't have an object that can possible
327 // span across two regions.
328 maybe_fill_gc_region_gap(byte_size);
329
330 size_t new_used = _buffer_used + byte_size;
331 assert(new_used > _buffer_used, "no wrap around");
332
333 size_t cur_min_region_bottom = align_down(_buffer_used, MIN_GC_REGION_ALIGNMENT);
334 size_t next_min_region_bottom = align_down(new_used, MIN_GC_REGION_ALIGNMENT);
335 assert(cur_min_region_bottom == next_min_region_bottom, "no object should cross minimal GC region boundaries");
336
337 ensure_buffer_space(new_used);
338
339 address from = cast_from_oop<address>(src_obj);
340 address to = offset_to_buffered_address<address>(_buffer_used);
341 assert(is_object_aligned(_buffer_used), "sanity");
342 assert(is_object_aligned(byte_size), "sanity");
343 memcpy(to, from, byte_size);
344
345 size_t buffered_obj_offset = _buffer_used;
346 _buffer_used = new_used;
347
348 return buffered_obj_offset;
349 }
350
351 void ArchiveHeapWriter::set_requested_address(ArchiveHeapInfo* info) {
352 assert(!info->is_used(), "only set once");
353 assert(UseG1GC, "must be");
354 address heap_end = (address)G1CollectedHeap::heap()->reserved().end();
355 log_info(cds, heap)("Heap end = %p", heap_end);
356
357 size_t heap_region_byte_size = _buffer_used;
358 assert(heap_region_byte_size > 0, "must archived at least one object!");
359
360
361 if (UseCompressedOops) {
362 _requested_bottom = align_down(heap_end - heap_region_byte_size, HeapRegion::GrainBytes);
363 } else {
364 // We always write the objects as if the heap started at this address. This
365 // makes the contents of the archive heap deterministic.
366 //
367 // Note that at runtime, the heap address is selected by the OS, so the archive
368 // heap will not be mapped at 0x10000000, and the contents need to be patched.
369 _requested_bottom = (address)NOCOOPS_REQUESTED_BASE;
370 }
371
372 assert(is_aligned(_requested_bottom, HeapRegion::GrainBytes), "sanity");
373
374 _requested_top = _requested_bottom + _buffer_used;
375
376 info->set_buffer_region(MemRegion(offset_to_buffered_address<HeapWord*>(0),
377 offset_to_buffered_address<HeapWord*>(_buffer_used)));
378 info->set_heap_roots_offset(_heap_roots_offset);
379 }
380
381 // Oop relocation
382
383 template <typename T> T* ArchiveHeapWriter::requested_addr_to_buffered_addr(T* p) {
384 assert(is_in_requested_range(cast_to_oop(p)), "must be");
385
386 address addr = address(p);
387 assert(addr >= _requested_bottom, "must be");
388 size_t offset = addr - _requested_bottom;
389 return offset_to_buffered_address<T*>(offset);
390 }
391
392 template <typename T> oop ArchiveHeapWriter::load_source_oop_from_buffer(T* buffered_addr) {
393 oop o = load_oop_from_buffer(buffered_addr);
394 assert(!in_buffer(cast_from_oop<address>(o)), "must point to source oop");
395 return o;
396 }
397
398 template <typename T> void ArchiveHeapWriter::store_requested_oop_in_buffer(T* buffered_addr,
399 oop request_oop) {
400 assert(is_in_requested_range(request_oop), "must be");
401 store_oop_in_buffer(buffered_addr, request_oop);
402 }
403
404 inline void ArchiveHeapWriter::store_oop_in_buffer(oop* buffered_addr, oop requested_obj) {
405 *buffered_addr = requested_obj;
406 }
407
408 inline void ArchiveHeapWriter::store_oop_in_buffer(narrowOop* buffered_addr, oop requested_obj) {
409 narrowOop val = CompressedOops::encode_not_null(requested_obj);
410 *buffered_addr = val;
411 }
412
413 oop ArchiveHeapWriter::load_oop_from_buffer(oop* buffered_addr) {
414 return *buffered_addr;
415 }
416
417 oop ArchiveHeapWriter::load_oop_from_buffer(narrowOop* buffered_addr) {
418 return CompressedOops::decode(*buffered_addr);
419 }
420
421 template <typename T> void ArchiveHeapWriter::relocate_field_in_buffer(T* field_addr_in_buffer, CHeapBitMap* oopmap) {
422 oop source_referent = load_source_oop_from_buffer<T>(field_addr_in_buffer);
423 if (!CompressedOops::is_null(source_referent)) {
424 oop request_referent = source_obj_to_requested_obj(source_referent);
425 store_requested_oop_in_buffer<T>(field_addr_in_buffer, request_referent);
426 mark_oop_pointer<T>(field_addr_in_buffer, oopmap);
427 }
428 }
429
430 template <typename T> void ArchiveHeapWriter::mark_oop_pointer(T* buffered_addr, CHeapBitMap* oopmap) {
431 T* request_p = (T*)(buffered_addr_to_requested_addr((address)buffered_addr));
432 address requested_region_bottom;
433
434 assert(request_p >= (T*)_requested_bottom, "sanity");
435 assert(request_p < (T*)_requested_top, "sanity");
436 requested_region_bottom = _requested_bottom;
437
438 // Mark the pointer in the oopmap
439 T* region_bottom = (T*)requested_region_bottom;
440 assert(request_p >= region_bottom, "must be");
441 BitMap::idx_t idx = request_p - region_bottom;
442 assert(idx < oopmap->size(), "overflow");
443 oopmap->set_bit(idx);
444 }
445
446 void ArchiveHeapWriter::update_header_for_requested_obj(oop requested_obj, oop src_obj, Klass* src_klass) {
447 assert(UseCompressedClassPointers, "Archived heap only supported for compressed klasses");
448 narrowKlass nk = ArchiveBuilder::current()->get_requested_narrow_klass(src_klass);
449 address buffered_addr = requested_addr_to_buffered_addr(cast_from_oop<address>(requested_obj));
450
451 oop fake_oop = cast_to_oop(buffered_addr);
452 fake_oop->set_narrow_klass(nk);
453
454 // We need to retain the identity_hash, because it may have been used by some hashtables
455 // in the shared heap. This also has the side effect of pre-initializing the
456 // identity_hash for all shared objects, so they are less likely to be written
457 // into during run time, increasing the potential of memory sharing.
458 if (src_obj != nullptr) {
459 int src_hash = src_obj->identity_hash();
460 fake_oop->set_mark(markWord::prototype().copy_set_hash(src_hash));
461 assert(fake_oop->mark().is_unlocked(), "sanity");
462
463 DEBUG_ONLY(int archived_hash = fake_oop->identity_hash());
464 assert(src_hash == archived_hash, "Different hash codes: original %x, archived %x", src_hash, archived_hash);
465 }
466 }
467
468 // Relocate an element in the buffered copy of HeapShared::roots()
469 template <typename T> void ArchiveHeapWriter::relocate_root_at(oop requested_roots, int index, CHeapBitMap* oopmap) {
470 size_t offset = (size_t)((objArrayOop)requested_roots)->obj_at_offset<T>(index);
471 relocate_field_in_buffer<T>((T*)(buffered_heap_roots_addr() + offset), oopmap);
472 }
473
474 class ArchiveHeapWriter::EmbeddedOopRelocator: public BasicOopIterateClosure {
475 oop _src_obj;
476 address _buffered_obj;
477 CHeapBitMap* _oopmap;
478
479 public:
480 EmbeddedOopRelocator(oop src_obj, address buffered_obj, CHeapBitMap* oopmap) :
481 _src_obj(src_obj), _buffered_obj(buffered_obj), _oopmap(oopmap) {}
482
483 void do_oop(narrowOop *p) { EmbeddedOopRelocator::do_oop_work(p); }
484 void do_oop( oop *p) { EmbeddedOopRelocator::do_oop_work(p); }
485
486 private:
487 template <class T> void do_oop_work(T *p) {
488 size_t field_offset = pointer_delta(p, _src_obj, sizeof(char));
489 ArchiveHeapWriter::relocate_field_in_buffer<T>((T*)(_buffered_obj + field_offset), _oopmap);
490 }
491 };
492
493 // Update all oop fields embedded in the buffered objects
494 void ArchiveHeapWriter::relocate_embedded_oops(GrowableArrayCHeap<oop, mtClassShared>* roots,
495 ArchiveHeapInfo* heap_info) {
496 size_t oopmap_unit = (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop));
497 size_t heap_region_byte_size = _buffer_used;
498 heap_info->oopmap()->resize(heap_region_byte_size / oopmap_unit);
499
500 auto iterator = [&] (oop src_obj, HeapShared::CachedOopInfo& info) {
501 oop requested_obj = requested_obj_from_buffer_offset(info.buffer_offset());
502 update_header_for_requested_obj(requested_obj, src_obj, src_obj->klass());
503 address buffered_obj = offset_to_buffered_address<address>(info.buffer_offset());
504 EmbeddedOopRelocator relocator(src_obj, buffered_obj, heap_info->oopmap());
505 src_obj->oop_iterate(&relocator);
506 };
507 HeapShared::archived_object_cache()->iterate_all(iterator);
508
509 // Relocate HeapShared::roots(), which is created in copy_roots_to_buffer() and
510 // doesn't have a corresponding src_obj, so we can't use EmbeddedOopRelocator on it.
511 oop requested_roots = requested_obj_from_buffer_offset(_heap_roots_offset);
512 update_header_for_requested_obj(requested_roots, nullptr, Universe::objectArrayKlassObj());
513 int length = roots != nullptr ? roots->length() : 0;
514 for (int i = 0; i < length; i++) {
515 if (UseCompressedOops) {
516 relocate_root_at<narrowOop>(requested_roots, i, heap_info->oopmap());
517 } else {
518 relocate_root_at<oop>(requested_roots, i, heap_info->oopmap());
519 }
520 }
521
522 compute_ptrmap(heap_info);
523 }
524
525 void ArchiveHeapWriter::mark_native_pointer(oop src_obj, int field_offset) {
526 Metadata* ptr = src_obj->metadata_field_acquire(field_offset);
527 if (ptr != nullptr) {
528 NativePointerInfo info;
529 info._src_obj = src_obj;
530 info._field_offset = field_offset;
531 _native_pointers->append(info);
532 }
533 }
534
535 // Do we have a jlong/jint field that's actually a pointer to a MetaspaceObj?
536 bool ArchiveHeapWriter::is_marked_as_native_pointer(ArchiveHeapInfo* heap_info, oop src_obj, int field_offset) {
537 HeapShared::CachedOopInfo* p = HeapShared::archived_object_cache()->get(src_obj);
538 assert(p != nullptr, "must be");
539
540 // requested_field_addr = the address of this field in the requested space
541 oop requested_obj = requested_obj_from_buffer_offset(p->buffer_offset());
542 Metadata** requested_field_addr = (Metadata**)(cast_from_oop<address>(requested_obj) + field_offset);
543 assert((Metadata**)_requested_bottom <= requested_field_addr && requested_field_addr < (Metadata**) _requested_top, "range check");
544
545 BitMap::idx_t idx = requested_field_addr - (Metadata**) _requested_bottom;
546 return (idx < heap_info->ptrmap()->size()) && (heap_info->ptrmap()->at(idx) == true);
547 }
548
549 void ArchiveHeapWriter::compute_ptrmap(ArchiveHeapInfo* heap_info) {
550 int num_non_null_ptrs = 0;
551 Metadata** bottom = (Metadata**) _requested_bottom;
552 Metadata** top = (Metadata**) _requested_top; // exclusive
553 heap_info->ptrmap()->resize(top - bottom);
554
555 BitMap::idx_t max_idx = 32; // paranoid - don't make it too small
556 for (int i = 0; i < _native_pointers->length(); i++) {
557 NativePointerInfo info = _native_pointers->at(i);
558 oop src_obj = info._src_obj;
559 int field_offset = info._field_offset;
560 HeapShared::CachedOopInfo* p = HeapShared::archived_object_cache()->get(src_obj);
561 // requested_field_addr = the address of this field in the requested space
562 oop requested_obj = requested_obj_from_buffer_offset(p->buffer_offset());
563 Metadata** requested_field_addr = (Metadata**)(cast_from_oop<address>(requested_obj) + field_offset);
564 assert(bottom <= requested_field_addr && requested_field_addr < top, "range check");
565
566 // Mark this field in the bitmap
567 BitMap::idx_t idx = requested_field_addr - bottom;
568 heap_info->ptrmap()->set_bit(idx);
569 num_non_null_ptrs ++;
570 max_idx = MAX2(max_idx, idx);
571
572 // Set the native pointer to the requested address of the metadata (at runtime, the metadata will have
573 // this address if the RO/RW regions are mapped at the default location).
574
575 Metadata** buffered_field_addr = requested_addr_to_buffered_addr(requested_field_addr);
576 Metadata* native_ptr = *buffered_field_addr;
577 assert(native_ptr != nullptr, "sanity");
578
579 address buffered_native_ptr = ArchiveBuilder::current()->get_buffered_addr((address)native_ptr);
580 address requested_native_ptr = ArchiveBuilder::current()->to_requested(buffered_native_ptr);
581 *buffered_field_addr = (Metadata*)requested_native_ptr;
582 }
583
584 heap_info->ptrmap()->resize(max_idx + 1);
585 log_info(cds, heap)("calculate_ptrmap: marked %d non-null native pointers for heap region (" SIZE_FORMAT " bits)",
586 num_non_null_ptrs, size_t(heap_info->ptrmap()->size()));
587 }
588
589 #endif // INCLUDE_CDS_JAVA_HEAP