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