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 "classfile/javaClasses.hpp"
31 #include "classfile/modules.hpp"
32 #include "classfile/systemDictionary.hpp"
33 #include "gc/shared/collectedHeap.hpp"
34 #include "memory/iterator.inline.hpp"
35 #include "memory/oopFactory.hpp"
36 #include "memory/universe.hpp"
37 #include "oops/compressedOops.hpp"
38 #include "oops/objArrayOop.inline.hpp"
39 #include "oops/oop.inline.hpp"
40 #include "oops/oopHandle.inline.hpp"
41 #include "oops/typeArrayKlass.hpp"
42 #include "oops/typeArrayOop.hpp"
43 #include "runtime/java.hpp"
44 #include "runtime/mutexLocker.hpp"
45 #include "utilities/bitMap.inline.hpp"
46 #if INCLUDE_G1GC
47 #include "gc/g1/g1CollectedHeap.hpp"
48 #include "gc/g1/g1HeapRegion.hpp"
49 #endif
50
51 #if INCLUDE_CDS_JAVA_HEAP
52
53 GrowableArrayCHeap<u1, mtClassShared>* ArchiveHeapWriter::_buffer = nullptr;
54
55 // The following are offsets from buffer_bottom()
56 size_t ArchiveHeapWriter::_buffer_used;
57
58 // Heap root segments
59 HeapRootSegments ArchiveHeapWriter::_heap_root_segments;
60
61 address ArchiveHeapWriter::_requested_bottom;
62 address ArchiveHeapWriter::_requested_top;
63
64 GrowableArrayCHeap<ArchiveHeapWriter::NativePointerInfo, mtClassShared>* ArchiveHeapWriter::_native_pointers;
65 GrowableArrayCHeap<oop, mtClassShared>* ArchiveHeapWriter::_source_objs;
66 GrowableArrayCHeap<ArchiveHeapWriter::HeapObjOrder, mtClassShared>* ArchiveHeapWriter::_source_objs_order;
67
68 ArchiveHeapWriter::BufferOffsetToSourceObjectTable*
69 ArchiveHeapWriter::_buffer_offset_to_source_obj_table = nullptr;
70
71
72 typedef ResourceHashtable<
73 size_t, // offset of a filler from ArchiveHeapWriter::buffer_bottom()
74 size_t, // size of this filler (in bytes)
75 127, // prime number
76 AnyObj::C_HEAP,
77 mtClassShared> FillersTable;
78 static FillersTable* _fillers;
79 static int _num_native_ptrs = 0;
80
81 void ArchiveHeapWriter::init() {
82 if (CDSConfig::is_dumping_heap()) {
83 Universe::heap()->collect(GCCause::_java_lang_system_gc);
84
85 _buffer_offset_to_source_obj_table = new BufferOffsetToSourceObjectTable(/*size (prime)*/36137, /*max size*/1 * M);
86 _fillers = new FillersTable();
87 _requested_bottom = nullptr;
88 _requested_top = nullptr;
89
90 _native_pointers = new GrowableArrayCHeap<NativePointerInfo, mtClassShared>(2048);
91 _source_objs = new GrowableArrayCHeap<oop, mtClassShared>(10000);
92
93 guarantee(MIN_GC_REGION_ALIGNMENT <= G1HeapRegion::min_region_size_in_words() * HeapWordSize, "must be");
94 }
95 }
96
97 void ArchiveHeapWriter::add_source_obj(oop src_obj) {
98 _source_objs->append(src_obj);
99 }
100
101 void ArchiveHeapWriter::write(GrowableArrayCHeap<oop, mtClassShared>* roots,
102 ArchiveHeapInfo* heap_info) {
103 assert(CDSConfig::is_dumping_heap(), "sanity");
104 allocate_buffer();
105 copy_source_objs_to_buffer(roots);
106 set_requested_address(heap_info);
107 relocate_embedded_oops(roots, heap_info);
108 }
109
110 bool ArchiveHeapWriter::is_too_large_to_archive(oop o) {
111 return is_too_large_to_archive(o->size());
112 }
113
114 bool ArchiveHeapWriter::is_string_too_large_to_archive(oop string) {
115 typeArrayOop value = java_lang_String::value_no_keepalive(string);
116 return is_too_large_to_archive(value);
117 }
118
119 bool ArchiveHeapWriter::is_too_large_to_archive(size_t size) {
120 assert(size > 0, "no zero-size object");
121 assert(size * HeapWordSize > size, "no overflow");
122 static_assert(MIN_GC_REGION_ALIGNMENT > 0, "must be positive");
123
124 size_t byte_size = size * HeapWordSize;
125 if (byte_size > size_t(MIN_GC_REGION_ALIGNMENT)) {
126 return true;
127 } else {
128 return false;
129 }
130 }
131
132 // Various lookup functions between source_obj, buffered_obj and requested_obj
133 bool ArchiveHeapWriter::is_in_requested_range(oop o) {
134 assert(_requested_bottom != nullptr, "do not call before _requested_bottom is initialized");
135 address a = cast_from_oop<address>(o);
136 return (_requested_bottom <= a && a < _requested_top);
137 }
138
139 oop ArchiveHeapWriter::requested_obj_from_buffer_offset(size_t offset) {
140 oop req_obj = cast_to_oop(_requested_bottom + offset);
141 assert(is_in_requested_range(req_obj), "must be");
142 return req_obj;
143 }
144
145 oop ArchiveHeapWriter::source_obj_to_requested_obj(oop src_obj) {
146 assert(CDSConfig::is_dumping_heap(), "dump-time only");
147 HeapShared::CachedOopInfo* p = HeapShared::archived_object_cache()->get(src_obj);
148 if (p != nullptr) {
149 return requested_obj_from_buffer_offset(p->buffer_offset());
150 } else {
151 return nullptr;
152 }
153 }
154
155 oop ArchiveHeapWriter::buffered_addr_to_source_obj(address buffered_addr) {
156 oop* p = _buffer_offset_to_source_obj_table->get(buffered_address_to_offset(buffered_addr));
157 if (p != nullptr) {
158 return *p;
159 } else {
160 return nullptr;
161 }
162 }
163
164 address ArchiveHeapWriter::buffered_addr_to_requested_addr(address buffered_addr) {
165 return _requested_bottom + buffered_address_to_offset(buffered_addr);
166 }
167
168 address ArchiveHeapWriter::requested_address() {
169 assert(_buffer != nullptr, "must be initialized");
170 return _requested_bottom;
171 }
172
173 void ArchiveHeapWriter::allocate_buffer() {
174 int initial_buffer_size = 100000;
175 _buffer = new GrowableArrayCHeap<u1, mtClassShared>(initial_buffer_size);
176 _buffer_used = 0;
177 ensure_buffer_space(1); // so that buffer_bottom() works
178 }
179
180 void ArchiveHeapWriter::ensure_buffer_space(size_t min_bytes) {
181 // We usually have very small heaps. If we get a huge one it's probably caused by a bug.
182 guarantee(min_bytes <= max_jint, "we dont support archiving more than 2G of objects");
183 _buffer->at_grow(to_array_index(min_bytes));
184 }
185
186 objArrayOop ArchiveHeapWriter::allocate_root_segment(size_t offset, int element_count) {
187 HeapWord* mem = offset_to_buffered_address<HeapWord *>(offset);
188 memset(mem, 0, objArrayOopDesc::object_size(element_count));
189
190 // The initialization code is copied from MemAllocator::finish and ObjArrayAllocator::initialize.
191 if (UseCompactObjectHeaders) {
192 oopDesc::release_set_mark(mem, Universe::objectArrayKlass()->prototype_header());
193 } else {
194 oopDesc::set_mark(mem, markWord::prototype());
195 oopDesc::release_set_klass(mem, Universe::objectArrayKlass());
196 }
197 arrayOopDesc::set_length(mem, element_count);
198 return objArrayOop(cast_to_oop(mem));
199 }
200
201 void ArchiveHeapWriter::root_segment_at_put(objArrayOop segment, int index, oop root) {
202 // Do not use arrayOop->obj_at_put(i, o) as arrayOop is outside the real heap!
203 if (UseCompressedOops) {
204 *segment->obj_at_addr<narrowOop>(index) = CompressedOops::encode(root);
205 } else {
206 *segment->obj_at_addr<oop>(index) = root;
207 }
208 }
209
210 void ArchiveHeapWriter::copy_roots_to_buffer(GrowableArrayCHeap<oop, mtClassShared>* roots) {
211 // Depending on the number of classes we are archiving, a single roots array may be
212 // larger than MIN_GC_REGION_ALIGNMENT. Roots are allocated first in the buffer, which
213 // allows us to chop the large array into a series of "segments". Current layout
214 // starts with zero or more segments exactly fitting MIN_GC_REGION_ALIGNMENT, and end
215 // with a single segment that may be smaller than MIN_GC_REGION_ALIGNMENT.
216 // This is simple and efficient. We do not need filler objects anywhere between the segments,
217 // or immediately after the last segment. This allows starting the object dump immediately
218 // after the roots.
219
220 assert((_buffer_used % MIN_GC_REGION_ALIGNMENT) == 0,
221 "Pre-condition: Roots start at aligned boundary: %zu", _buffer_used);
222
223 int max_elem_count = ((MIN_GC_REGION_ALIGNMENT - arrayOopDesc::header_size_in_bytes()) / heapOopSize);
224 assert(objArrayOopDesc::object_size(max_elem_count)*HeapWordSize == MIN_GC_REGION_ALIGNMENT,
225 "Should match exactly");
226
227 HeapRootSegments segments(_buffer_used,
228 roots->length(),
229 MIN_GC_REGION_ALIGNMENT,
230 max_elem_count);
231
232 int root_index = 0;
233 for (size_t seg_idx = 0; seg_idx < segments.count(); seg_idx++) {
234 int size_elems = segments.size_in_elems(seg_idx);
235 size_t size_bytes = segments.size_in_bytes(seg_idx);
236
237 size_t oop_offset = _buffer_used;
238 _buffer_used = oop_offset + size_bytes;
239 ensure_buffer_space(_buffer_used);
240
241 assert((oop_offset % MIN_GC_REGION_ALIGNMENT) == 0,
242 "Roots segment %zu start is not aligned: %zu",
243 segments.count(), oop_offset);
244
245 objArrayOop seg_oop = allocate_root_segment(oop_offset, size_elems);
246 for (int i = 0; i < size_elems; i++) {
247 root_segment_at_put(seg_oop, i, roots->at(root_index++));
248 }
249
250 log_info(cds, heap)("archived obj root segment [%d] = %zu bytes, obj = " PTR_FORMAT,
251 size_elems, size_bytes, p2i(seg_oop));
252 }
253
254 assert(root_index == roots->length(), "Post-condition: All roots are handled");
255
256 _heap_root_segments = segments;
257 }
258
259 // The goal is to sort the objects in increasing order of:
260 // - objects that have only oop pointers
261 // - objects that have both native and oop pointers
262 // - objects that have only native pointers
263 // - objects that have no pointers
264 static int oop_sorting_rank(oop o) {
265 bool has_oop_ptr, has_native_ptr;
266 HeapShared::get_pointer_info(o, has_oop_ptr, has_native_ptr);
267
268 if (has_oop_ptr) {
269 if (!has_native_ptr) {
270 return 0;
271 } else {
272 return 1;
273 }
274 } else {
275 if (has_native_ptr) {
276 return 2;
277 } else {
278 return 3;
279 }
280 }
281 }
282
283 int ArchiveHeapWriter::compare_objs_by_oop_fields(HeapObjOrder* a, HeapObjOrder* b) {
284 int rank_a = a->_rank;
285 int rank_b = b->_rank;
286
287 if (rank_a != rank_b) {
288 return rank_a - rank_b;
289 } else {
290 // If they are the same rank, sort them by their position in the _source_objs array
291 return a->_index - b->_index;
292 }
293 }
294
295 void ArchiveHeapWriter::sort_source_objs() {
296 log_info(cds)("sorting heap objects");
297 int len = _source_objs->length();
298 _source_objs_order = new GrowableArrayCHeap<HeapObjOrder, mtClassShared>(len);
299
300 for (int i = 0; i < len; i++) {
301 oop o = _source_objs->at(i);
302 int rank = oop_sorting_rank(o);
303 HeapObjOrder os = {i, rank};
304 _source_objs_order->append(os);
305 }
306 log_info(cds)("computed ranks");
307 _source_objs_order->sort(compare_objs_by_oop_fields);
308 log_info(cds)("sorting heap objects done");
309 }
310
311 void ArchiveHeapWriter::copy_source_objs_to_buffer(GrowableArrayCHeap<oop, mtClassShared>* roots) {
312 // There could be multiple root segments, which we want to be aligned by region.
313 // Putting them ahead of objects makes sure we waste no space.
314 copy_roots_to_buffer(roots);
315
316 sort_source_objs();
317 for (int i = 0; i < _source_objs_order->length(); i++) {
318 int src_obj_index = _source_objs_order->at(i)._index;
319 oop src_obj = _source_objs->at(src_obj_index);
320 HeapShared::CachedOopInfo* info = HeapShared::archived_object_cache()->get(src_obj);
321 assert(info != nullptr, "must be");
322 size_t buffer_offset = copy_one_source_obj_to_buffer(src_obj);
323 info->set_buffer_offset(buffer_offset);
324
325 _buffer_offset_to_source_obj_table->put_when_absent(buffer_offset, src_obj);
326 _buffer_offset_to_source_obj_table->maybe_grow();
327
328 if (java_lang_Module::is_instance(src_obj)) {
329 Modules::check_archived_module_oop(src_obj);
330 }
331 }
332
333 log_info(cds)("Size of heap region = %zu bytes, %d objects, %d roots, %d native ptrs",
334 _buffer_used, _source_objs->length() + 1, roots->length(), _num_native_ptrs);
335 }
336
337 size_t ArchiveHeapWriter::filler_array_byte_size(int length) {
338 size_t byte_size = objArrayOopDesc::object_size(length) * HeapWordSize;
339 return byte_size;
340 }
341
342 int ArchiveHeapWriter::filler_array_length(size_t fill_bytes) {
343 assert(is_object_aligned(fill_bytes), "must be");
344 size_t elemSize = (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop));
345
346 int initial_length = to_array_length(fill_bytes / elemSize);
347 for (int length = initial_length; length >= 0; length --) {
348 size_t array_byte_size = filler_array_byte_size(length);
349 if (array_byte_size == fill_bytes) {
350 return length;
351 }
352 }
353
354 ShouldNotReachHere();
355 return -1;
356 }
357
358 HeapWord* ArchiveHeapWriter::init_filler_array_at_buffer_top(int array_length, size_t fill_bytes) {
359 assert(UseCompressedClassPointers, "Archived heap only supported for compressed klasses");
360 Klass* oak = Universe::objectArrayKlass(); // already relocated to point to archived klass
361 HeapWord* mem = offset_to_buffered_address<HeapWord*>(_buffer_used);
362 memset(mem, 0, fill_bytes);
363 narrowKlass nk = ArchiveBuilder::current()->get_requested_narrow_klass(oak);
364 if (UseCompactObjectHeaders) {
365 oopDesc::release_set_mark(mem, markWord::prototype().set_narrow_klass(nk));
366 } else {
367 oopDesc::set_mark(mem, markWord::prototype());
368 cast_to_oop(mem)->set_narrow_klass(nk);
369 }
370 arrayOopDesc::set_length(mem, array_length);
371 return mem;
372 }
373
374 void ArchiveHeapWriter::maybe_fill_gc_region_gap(size_t required_byte_size) {
375 // We fill only with arrays (so we don't need to use a single HeapWord filler if the
376 // leftover space is smaller than a zero-sized array object). Therefore, we need to
377 // make sure there's enough space of min_filler_byte_size in the current region after
378 // required_byte_size has been allocated. If not, fill the remainder of the current
379 // region.
380 size_t min_filler_byte_size = filler_array_byte_size(0);
381 size_t new_used = _buffer_used + required_byte_size + min_filler_byte_size;
382
383 const size_t cur_min_region_bottom = align_down(_buffer_used, MIN_GC_REGION_ALIGNMENT);
384 const size_t next_min_region_bottom = align_down(new_used, MIN_GC_REGION_ALIGNMENT);
385
386 if (cur_min_region_bottom != next_min_region_bottom) {
387 // Make sure that no objects span across MIN_GC_REGION_ALIGNMENT. This way
388 // we can map the region in any region-based collector.
389 assert(next_min_region_bottom > cur_min_region_bottom, "must be");
390 assert(next_min_region_bottom - cur_min_region_bottom == MIN_GC_REGION_ALIGNMENT,
391 "no buffered object can be larger than %d bytes", MIN_GC_REGION_ALIGNMENT);
392
393 const size_t filler_end = next_min_region_bottom;
394 const size_t fill_bytes = filler_end - _buffer_used;
395 assert(fill_bytes > 0, "must be");
396 ensure_buffer_space(filler_end);
397
398 int array_length = filler_array_length(fill_bytes);
399 log_info(cds, heap)("Inserting filler obj array of %d elements (%zu bytes total) @ buffer offset %zu",
400 array_length, fill_bytes, _buffer_used);
401 HeapWord* filler = init_filler_array_at_buffer_top(array_length, fill_bytes);
402 _buffer_used = filler_end;
403 _fillers->put(buffered_address_to_offset((address)filler), fill_bytes);
404 }
405 }
406
407 size_t ArchiveHeapWriter::get_filler_size_at(address buffered_addr) {
408 size_t* p = _fillers->get(buffered_address_to_offset(buffered_addr));
409 if (p != nullptr) {
410 assert(*p > 0, "filler must be larger than zero bytes");
411 return *p;
412 } else {
413 return 0; // buffered_addr is not a filler
414 }
415 }
416
417 template <typename T>
418 void update_buffered_object_field(address buffered_obj, int field_offset, T value) {
419 T* field_addr = cast_to_oop(buffered_obj)->field_addr<T>(field_offset);
420 *field_addr = value;
421 }
422
423 size_t ArchiveHeapWriter::copy_one_source_obj_to_buffer(oop src_obj) {
424 assert(!is_too_large_to_archive(src_obj), "already checked");
425 size_t byte_size = src_obj->size() * HeapWordSize;
426 assert(byte_size > 0, "no zero-size objects");
427
428 // For region-based collectors such as G1, the archive heap may be mapped into
429 // multiple regions. We need to make sure that we don't have an object that can possible
430 // span across two regions.
431 maybe_fill_gc_region_gap(byte_size);
432
433 size_t new_used = _buffer_used + byte_size;
434 assert(new_used > _buffer_used, "no wrap around");
435
436 size_t cur_min_region_bottom = align_down(_buffer_used, MIN_GC_REGION_ALIGNMENT);
437 size_t next_min_region_bottom = align_down(new_used, MIN_GC_REGION_ALIGNMENT);
438 assert(cur_min_region_bottom == next_min_region_bottom, "no object should cross minimal GC region boundaries");
439
440 ensure_buffer_space(new_used);
441
442 address from = cast_from_oop<address>(src_obj);
443 address to = offset_to_buffered_address<address>(_buffer_used);
444 assert(is_object_aligned(_buffer_used), "sanity");
445 assert(is_object_aligned(byte_size), "sanity");
446 memcpy(to, from, byte_size);
447
448 // These native pointers will be restored explicitly at run time.
449 if (java_lang_Module::is_instance(src_obj)) {
450 update_buffered_object_field<ModuleEntry*>(to, java_lang_Module::module_entry_offset(), nullptr);
451 } else if (java_lang_ClassLoader::is_instance(src_obj)) {
452 #ifdef ASSERT
453 // We only archive these loaders
454 if (src_obj != SystemDictionary::java_platform_loader() &&
455 src_obj != SystemDictionary::java_system_loader()) {
456 assert(src_obj->klass()->name()->equals("jdk/internal/loader/ClassLoaders$BootClassLoader"), "must be");
457 }
458 #endif
459 update_buffered_object_field<ClassLoaderData*>(to, java_lang_ClassLoader::loader_data_offset(), nullptr);
460 }
461
462 size_t buffered_obj_offset = _buffer_used;
463 _buffer_used = new_used;
464
465 return buffered_obj_offset;
466 }
467
468 void ArchiveHeapWriter::set_requested_address(ArchiveHeapInfo* info) {
469 assert(!info->is_used(), "only set once");
470
471 size_t heap_region_byte_size = _buffer_used;
472 assert(heap_region_byte_size > 0, "must archived at least one object!");
473
474 if (UseCompressedOops) {
475 if (UseG1GC) {
476 address heap_end = (address)G1CollectedHeap::heap()->reserved().end();
477 log_info(cds, heap)("Heap end = %p", heap_end);
478 _requested_bottom = align_down(heap_end - heap_region_byte_size, G1HeapRegion::GrainBytes);
479 _requested_bottom = align_down(_requested_bottom, MIN_GC_REGION_ALIGNMENT);
480 assert(is_aligned(_requested_bottom, G1HeapRegion::GrainBytes), "sanity");
481 } else {
482 _requested_bottom = align_up(CompressedOops::begin(), MIN_GC_REGION_ALIGNMENT);
483 }
484 } else {
485 // We always write the objects as if the heap started at this address. This
486 // makes the contents of the archive heap deterministic.
487 //
488 // Note that at runtime, the heap address is selected by the OS, so the archive
489 // heap will not be mapped at 0x10000000, and the contents need to be patched.
490 _requested_bottom = align_up((address)NOCOOPS_REQUESTED_BASE, MIN_GC_REGION_ALIGNMENT);
491 }
492
493 assert(is_aligned(_requested_bottom, MIN_GC_REGION_ALIGNMENT), "sanity");
494
495 _requested_top = _requested_bottom + _buffer_used;
496
497 info->set_buffer_region(MemRegion(offset_to_buffered_address<HeapWord*>(0),
498 offset_to_buffered_address<HeapWord*>(_buffer_used)));
499 info->set_heap_root_segments(_heap_root_segments);
500 }
501
502 // Oop relocation
503
504 template <typename T> T* ArchiveHeapWriter::requested_addr_to_buffered_addr(T* p) {
505 assert(is_in_requested_range(cast_to_oop(p)), "must be");
506
507 address addr = address(p);
508 assert(addr >= _requested_bottom, "must be");
509 size_t offset = addr - _requested_bottom;
510 return offset_to_buffered_address<T*>(offset);
511 }
512
513 template <typename T> oop ArchiveHeapWriter::load_source_oop_from_buffer(T* buffered_addr) {
514 oop o = load_oop_from_buffer(buffered_addr);
515 assert(!in_buffer(cast_from_oop<address>(o)), "must point to source oop");
516 return o;
517 }
518
519 template <typename T> void ArchiveHeapWriter::store_requested_oop_in_buffer(T* buffered_addr,
520 oop request_oop) {
521 assert(is_in_requested_range(request_oop), "must be");
522 store_oop_in_buffer(buffered_addr, request_oop);
523 }
524
525 inline void ArchiveHeapWriter::store_oop_in_buffer(oop* buffered_addr, oop requested_obj) {
526 *buffered_addr = requested_obj;
527 }
528
529 inline void ArchiveHeapWriter::store_oop_in_buffer(narrowOop* buffered_addr, oop requested_obj) {
530 narrowOop val = CompressedOops::encode_not_null(requested_obj);
531 *buffered_addr = val;
532 }
533
534 oop ArchiveHeapWriter::load_oop_from_buffer(oop* buffered_addr) {
535 return *buffered_addr;
536 }
537
538 oop ArchiveHeapWriter::load_oop_from_buffer(narrowOop* buffered_addr) {
539 return CompressedOops::decode(*buffered_addr);
540 }
541
542 template <typename T> void ArchiveHeapWriter::relocate_field_in_buffer(T* field_addr_in_buffer, CHeapBitMap* oopmap) {
543 oop source_referent = load_source_oop_from_buffer<T>(field_addr_in_buffer);
544 if (source_referent != nullptr) {
545 if (java_lang_Class::is_instance(source_referent)) {
546 // When the source object points to a "real" mirror, the buffered object should point
547 // to the "scratch" mirror, which has all unarchivable fields scrubbed (to be reinstated
548 // at run time).
549 source_referent = HeapShared::scratch_java_mirror(source_referent);
550 assert(source_referent != nullptr, "must be");
551 }
552 oop request_referent = source_obj_to_requested_obj(source_referent);
553 store_requested_oop_in_buffer<T>(field_addr_in_buffer, request_referent);
554 mark_oop_pointer<T>(field_addr_in_buffer, oopmap);
555 }
556 }
557
558 template <typename T> void ArchiveHeapWriter::mark_oop_pointer(T* buffered_addr, CHeapBitMap* oopmap) {
559 T* request_p = (T*)(buffered_addr_to_requested_addr((address)buffered_addr));
560 address requested_region_bottom;
561
562 assert(request_p >= (T*)_requested_bottom, "sanity");
563 assert(request_p < (T*)_requested_top, "sanity");
564 requested_region_bottom = _requested_bottom;
565
566 // Mark the pointer in the oopmap
567 T* region_bottom = (T*)requested_region_bottom;
568 assert(request_p >= region_bottom, "must be");
569 BitMap::idx_t idx = request_p - region_bottom;
570 assert(idx < oopmap->size(), "overflow");
571 oopmap->set_bit(idx);
572 }
573
574 void ArchiveHeapWriter::update_header_for_requested_obj(oop requested_obj, oop src_obj, Klass* src_klass) {
575 assert(UseCompressedClassPointers, "Archived heap only supported for compressed klasses");
576 narrowKlass nk = ArchiveBuilder::current()->get_requested_narrow_klass(src_klass);
577 address buffered_addr = requested_addr_to_buffered_addr(cast_from_oop<address>(requested_obj));
578
579 oop fake_oop = cast_to_oop(buffered_addr);
580 if (UseCompactObjectHeaders) {
581 fake_oop->set_mark(markWord::prototype().set_narrow_klass(nk));
582 } else {
583 fake_oop->set_narrow_klass(nk);
584 }
585
586 if (src_obj == nullptr) {
587 return;
588 }
589 // We need to retain the identity_hash, because it may have been used by some hashtables
590 // in the shared heap.
591 if (!src_obj->fast_no_hash_check()) {
592 intptr_t src_hash = src_obj->identity_hash();
593 if (UseCompactObjectHeaders) {
594 fake_oop->set_mark(markWord::prototype().set_narrow_klass(nk).copy_set_hash(src_hash));
595 } else {
596 fake_oop->set_mark(markWord::prototype().copy_set_hash(src_hash));
597 }
598 assert(fake_oop->mark().is_unlocked(), "sanity");
599
600 DEBUG_ONLY(intptr_t archived_hash = fake_oop->identity_hash());
601 assert(src_hash == archived_hash, "Different hash codes: original " INTPTR_FORMAT ", archived " INTPTR_FORMAT, src_hash, archived_hash);
602 }
603 // Strip age bits.
604 fake_oop->set_mark(fake_oop->mark().set_age(0));
605 }
606
607 class ArchiveHeapWriter::EmbeddedOopRelocator: public BasicOopIterateClosure {
608 oop _src_obj;
609 address _buffered_obj;
610 CHeapBitMap* _oopmap;
611 bool _is_java_lang_ref;
612 public:
613 EmbeddedOopRelocator(oop src_obj, address buffered_obj, CHeapBitMap* oopmap) :
614 _src_obj(src_obj), _buffered_obj(buffered_obj), _oopmap(oopmap)
615 {
616 _is_java_lang_ref = AOTReferenceObjSupport::check_if_ref_obj(src_obj);
617 }
618
619 void do_oop(narrowOop *p) { EmbeddedOopRelocator::do_oop_work(p); }
620 void do_oop( oop *p) { EmbeddedOopRelocator::do_oop_work(p); }
621
622 private:
623 template <class T> void do_oop_work(T *p) {
624 int field_offset = pointer_delta_as_int((char*)p, cast_from_oop<char*>(_src_obj));
625 T* field_addr = (T*)(_buffered_obj + field_offset);
626 if (_is_java_lang_ref && AOTReferenceObjSupport::skip_field(field_offset)) {
627 // Do not copy these fields. Set them to null
628 *field_addr = (T)0x0;
629 } else {
630 ArchiveHeapWriter::relocate_field_in_buffer<T>(field_addr, _oopmap);
631 }
632 }
633 };
634
635 static void log_bitmap_usage(const char* which, BitMap* bitmap, size_t total_bits) {
636 // The whole heap is covered by total_bits, but there are only non-zero bits within [start ... end).
637 size_t start = bitmap->find_first_set_bit(0);
638 size_t end = bitmap->size();
639 log_info(cds)("%s = %7zu ... %7zu (%3zu%% ... %3zu%% = %3zu%%)", which,
640 start, end,
641 start * 100 / total_bits,
642 end * 100 / total_bits,
643 (end - start) * 100 / total_bits);
644 }
645
646 // Update all oop fields embedded in the buffered objects
647 void ArchiveHeapWriter::relocate_embedded_oops(GrowableArrayCHeap<oop, mtClassShared>* roots,
648 ArchiveHeapInfo* heap_info) {
649 size_t oopmap_unit = (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop));
650 size_t heap_region_byte_size = _buffer_used;
651 heap_info->oopmap()->resize(heap_region_byte_size / oopmap_unit);
652
653 for (int i = 0; i < _source_objs_order->length(); i++) {
654 int src_obj_index = _source_objs_order->at(i)._index;
655 oop src_obj = _source_objs->at(src_obj_index);
656 HeapShared::CachedOopInfo* info = HeapShared::archived_object_cache()->get(src_obj);
657 assert(info != nullptr, "must be");
658 oop requested_obj = requested_obj_from_buffer_offset(info->buffer_offset());
659 update_header_for_requested_obj(requested_obj, src_obj, src_obj->klass());
660 address buffered_obj = offset_to_buffered_address<address>(info->buffer_offset());
661 EmbeddedOopRelocator relocator(src_obj, buffered_obj, heap_info->oopmap());
662 src_obj->oop_iterate(&relocator);
663 };
664
665 // Relocate HeapShared::roots(), which is created in copy_roots_to_buffer() and
666 // doesn't have a corresponding src_obj, so we can't use EmbeddedOopRelocator on it.
667 for (size_t seg_idx = 0; seg_idx < _heap_root_segments.count(); seg_idx++) {
668 size_t seg_offset = _heap_root_segments.segment_offset(seg_idx);
669
670 objArrayOop requested_obj = (objArrayOop)requested_obj_from_buffer_offset(seg_offset);
671 update_header_for_requested_obj(requested_obj, nullptr, Universe::objectArrayKlass());
672 address buffered_obj = offset_to_buffered_address<address>(seg_offset);
673 int length = _heap_root_segments.size_in_elems(seg_idx);
674
675 if (UseCompressedOops) {
676 for (int i = 0; i < length; i++) {
677 narrowOop* addr = (narrowOop*)(buffered_obj + objArrayOopDesc::obj_at_offset<narrowOop>(i));
678 relocate_field_in_buffer<narrowOop>(addr, heap_info->oopmap());
679 }
680 } else {
681 for (int i = 0; i < length; i++) {
682 oop* addr = (oop*)(buffered_obj + objArrayOopDesc::obj_at_offset<oop>(i));
683 relocate_field_in_buffer<oop>(addr, heap_info->oopmap());
684 }
685 }
686 }
687
688 compute_ptrmap(heap_info);
689
690 size_t total_bytes = (size_t)_buffer->length();
691 log_bitmap_usage("oopmap", heap_info->oopmap(), total_bytes / (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop)));
692 log_bitmap_usage("ptrmap", heap_info->ptrmap(), total_bytes / sizeof(address));
693 }
694
695 void ArchiveHeapWriter::mark_native_pointer(oop src_obj, int field_offset) {
696 Metadata* ptr = src_obj->metadata_field_acquire(field_offset);
697 if (ptr != nullptr) {
698 NativePointerInfo info;
699 info._src_obj = src_obj;
700 info._field_offset = field_offset;
701 _native_pointers->append(info);
702 HeapShared::set_has_native_pointers(src_obj);
703 _num_native_ptrs ++;
704 }
705 }
706
707 // Do we have a jlong/jint field that's actually a pointer to a MetaspaceObj?
708 bool ArchiveHeapWriter::is_marked_as_native_pointer(ArchiveHeapInfo* heap_info, oop src_obj, int field_offset) {
709 HeapShared::CachedOopInfo* p = HeapShared::archived_object_cache()->get(src_obj);
710 assert(p != nullptr, "must be");
711
712 // requested_field_addr = the address of this field in the requested space
713 oop requested_obj = requested_obj_from_buffer_offset(p->buffer_offset());
714 Metadata** requested_field_addr = (Metadata**)(cast_from_oop<address>(requested_obj) + field_offset);
715 assert((Metadata**)_requested_bottom <= requested_field_addr && requested_field_addr < (Metadata**) _requested_top, "range check");
716
717 BitMap::idx_t idx = requested_field_addr - (Metadata**) _requested_bottom;
718 // Leading zeros have been removed so some addresses may not be in the ptrmap
719 size_t start_pos = FileMapInfo::current_info()->heap_ptrmap_start_pos();
720 if (idx < start_pos) {
721 return false;
722 } else {
723 idx -= start_pos;
724 }
725 return (idx < heap_info->ptrmap()->size()) && (heap_info->ptrmap()->at(idx) == true);
726 }
727
728 void ArchiveHeapWriter::compute_ptrmap(ArchiveHeapInfo* heap_info) {
729 int num_non_null_ptrs = 0;
730 Metadata** bottom = (Metadata**) _requested_bottom;
731 Metadata** top = (Metadata**) _requested_top; // exclusive
732 heap_info->ptrmap()->resize(top - bottom);
733
734 BitMap::idx_t max_idx = 32; // paranoid - don't make it too small
735 for (int i = 0; i < _native_pointers->length(); i++) {
736 NativePointerInfo info = _native_pointers->at(i);
737 oop src_obj = info._src_obj;
738 int field_offset = info._field_offset;
739 HeapShared::CachedOopInfo* p = HeapShared::archived_object_cache()->get(src_obj);
740 // requested_field_addr = the address of this field in the requested space
741 oop requested_obj = requested_obj_from_buffer_offset(p->buffer_offset());
742 Metadata** requested_field_addr = (Metadata**)(cast_from_oop<address>(requested_obj) + field_offset);
743 assert(bottom <= requested_field_addr && requested_field_addr < top, "range check");
744
745 // Mark this field in the bitmap
746 BitMap::idx_t idx = requested_field_addr - bottom;
747 heap_info->ptrmap()->set_bit(idx);
748 num_non_null_ptrs ++;
749 max_idx = MAX2(max_idx, idx);
750
751 // Set the native pointer to the requested address of the metadata (at runtime, the metadata will have
752 // this address if the RO/RW regions are mapped at the default location).
753
754 Metadata** buffered_field_addr = requested_addr_to_buffered_addr(requested_field_addr);
755 Metadata* native_ptr = *buffered_field_addr;
756 guarantee(native_ptr != nullptr, "sanity");
757 guarantee(ArchiveBuilder::current()->has_been_buffered((address)native_ptr),
758 "Metadata %p should have been archived", native_ptr);
759
760 address buffered_native_ptr = ArchiveBuilder::current()->get_buffered_addr((address)native_ptr);
761 address requested_native_ptr = ArchiveBuilder::current()->to_requested(buffered_native_ptr);
762 *buffered_field_addr = (Metadata*)requested_native_ptr;
763 }
764
765 heap_info->ptrmap()->resize(max_idx + 1);
766 log_info(cds, heap)("calculate_ptrmap: marked %d non-null native pointers for heap region (%zu bits)",
767 num_non_null_ptrs, size_t(heap_info->ptrmap()->size()));
768 }
769
770 #endif // INCLUDE_CDS_JAVA_HEAP