1 /*
2 * Copyright (c) 2023, 2026, 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/aotMappedHeap.hpp"
26 #include "cds/aotMappedHeapWriter.hpp"
27 #include "cds/aotReferenceObjSupport.hpp"
28 #include "cds/cdsConfig.hpp"
29 #include "cds/filemap.hpp"
30 #include "cds/heapShared.inline.hpp"
31 #include "cds/regeneratedClasses.hpp"
32 #include "classfile/javaClasses.hpp"
33 #include "classfile/modules.hpp"
34 #include "classfile/systemDictionary.hpp"
35 #include "gc/shared/collectedHeap.hpp"
36 #include "memory/allocation.inline.hpp"
37 #include "memory/iterator.inline.hpp"
38 #include "memory/oopFactory.hpp"
39 #include "memory/universe.hpp"
40 #include "oops/compressedOops.hpp"
41 #include "oops/objArrayOop.inline.hpp"
42 #include "oops/oop.inline.hpp"
43 #include "oops/oopHandle.inline.hpp"
44 #include "oops/typeArrayKlass.hpp"
45 #include "oops/typeArrayOop.hpp"
46 #include "runtime/java.hpp"
47 #include "runtime/mutexLocker.hpp"
48 #include "utilities/bitMap.inline.hpp"
49 #if INCLUDE_G1GC
50 #include "gc/g1/g1CollectedHeap.hpp"
51 #include "gc/g1/g1HeapRegion.hpp"
52 #endif
53
54 #if INCLUDE_CDS_JAVA_HEAP
55
56 GrowableArrayCHeap<u1, mtClassShared>* AOTMappedHeapWriter::_buffer = nullptr;
57
58 bool AOTMappedHeapWriter::_is_writing_deterministic_heap = false;
59 size_t AOTMappedHeapWriter::_buffer_used;
60
61 // Heap root segments
62 HeapRootSegments AOTMappedHeapWriter::_heap_root_segments;
63
64 address AOTMappedHeapWriter::_requested_bottom;
65 address AOTMappedHeapWriter::_requested_top;
66
67 static size_t _num_strings = 0;
68 static size_t _string_bytes = 0;
69 static size_t _num_packages = 0;
70 static size_t _num_protection_domains = 0;
71
72 GrowableArrayCHeap<AOTMappedHeapWriter::NativePointerInfo, mtClassShared>* AOTMappedHeapWriter::_native_pointers;
73 GrowableArrayCHeap<oop, mtClassShared>* AOTMappedHeapWriter::_source_objs;
74 GrowableArrayCHeap<AOTMappedHeapWriter::HeapObjOrder, mtClassShared>* AOTMappedHeapWriter::_source_objs_order;
75
76 AOTMappedHeapWriter::BufferOffsetToSourceObjectTable*
77 AOTMappedHeapWriter::_buffer_offset_to_source_obj_table = nullptr;
78
79 typedef HashTable<
80 size_t, // offset of a filler from AOTMappedHeapWriter::buffer_bottom()
81 size_t, // size of this filler (in bytes)
82 127, // prime number
83 AnyObj::C_HEAP,
84 mtClassShared> FillersTable;
85 static FillersTable* _fillers;
86 static int _num_native_ptrs = 0;
87
88 void AOTMappedHeapWriter::init() {
89 if (CDSConfig::is_dumping_heap()) {
90 Universe::heap()->collect(GCCause::_java_lang_system_gc);
91
92 _buffer_offset_to_source_obj_table = new (mtClassShared) BufferOffsetToSourceObjectTable(/*size (prime)*/36137, /*max size*/1 * M);
93 _fillers = new (mtClassShared) FillersTable();
94 _requested_bottom = nullptr;
95 _requested_top = nullptr;
96
97 _native_pointers = new GrowableArrayCHeap<NativePointerInfo, mtClassShared>(2048);
98 _source_objs = new GrowableArrayCHeap<oop, mtClassShared>(10000);
99
100 guarantee(MIN_GC_REGION_ALIGNMENT <= G1HeapRegion::min_region_size_in_words() * HeapWordSize, "must be");
101
102 if (CDSConfig::old_cds_flags_used()) {
103 // With the old CDS workflow, we can guatantee determninistic output: given
104 // the same classlist file, we can generate the same static CDS archive.
105 // To ensure determinism, we always use the same compressed oop encoding
106 // (zero-based, no shift). See set_requested_address_range().
107 _is_writing_deterministic_heap = true;
108 } else {
109 // Determninistic output is not supported by the new AOT workflow, so
110 // we don't force the (zero-based, no shift) encoding. This way, it is more
111 // likely that we can avoid oop relocation in the production run.
112 _is_writing_deterministic_heap = false;
113 }
114 }
115 }
116
117 // For AOTMappedHeapWriter::narrow_oop_{mode, base, shift}(), see comments
118 // in AOTMappedHeapWriter::set_requested_address_range(),
119 CompressedOops::Mode AOTMappedHeapWriter::narrow_oop_mode() {
120 if (is_writing_deterministic_heap()) {
121 return CompressedOops::UnscaledNarrowOop;
122 } else {
123 return CompressedOops::mode();
124 }
125 }
126
127 address AOTMappedHeapWriter::narrow_oop_base() {
128 if (is_writing_deterministic_heap()) {
129 return nullptr;
130 } else {
131 return CompressedOops::base();
132 }
133 }
134
135 int AOTMappedHeapWriter::narrow_oop_shift() {
136 if (is_writing_deterministic_heap()) {
137 return 0;
138 } else {
139 return CompressedOops::shift();
140 }
141 }
142
143 void AOTMappedHeapWriter::delete_tables_with_raw_oops() {
144 delete _source_objs;
145 _source_objs = nullptr;
146 }
147
148 void AOTMappedHeapWriter::add_source_obj(oop src_obj) {
149 _source_objs->append(src_obj);
150 }
151
152 void AOTMappedHeapWriter::write(GrowableArrayCHeap<oop, mtClassShared>* roots,
153 AOTMappedHeapInfo* heap_info) {
154 assert(CDSConfig::is_dumping_heap(), "sanity");
155 allocate_buffer();
156 copy_source_objs_to_buffer(roots);
157 set_requested_address_range(heap_info);
158 relocate_embedded_oops(roots, heap_info);
159 }
160
161 bool AOTMappedHeapWriter::is_too_large_to_archive(oop o) {
162 size_t size = o->size();
163 size = o->copy_size_cds(size, o->mark());
164 return is_too_large_to_archive(size);
165 }
166
167 bool AOTMappedHeapWriter::is_string_too_large_to_archive(oop string) {
168 typeArrayOop value = java_lang_String::value_no_keepalive(string);
169 return is_too_large_to_archive(value);
170 }
171
172 bool AOTMappedHeapWriter::is_too_large_to_archive(size_t size) {
173 assert(size > 0, "no zero-size object");
174 assert(size * HeapWordSize > size, "no overflow");
175 static_assert(MIN_GC_REGION_ALIGNMENT > 0, "must be positive");
176
177 size_t byte_size = size * HeapWordSize;
178 if (byte_size > size_t(MIN_GC_REGION_ALIGNMENT)) {
179 return true;
180 } else {
181 return false;
182 }
183 }
184
185 // Various lookup functions between source_obj, buffered_obj and requested_obj
186 bool AOTMappedHeapWriter::is_in_requested_range(oop o) {
187 assert(_requested_bottom != nullptr, "do not call before _requested_bottom is initialized");
188 address a = cast_from_oop<address>(o);
189 return (_requested_bottom <= a && a < _requested_top);
190 }
191
192 oop AOTMappedHeapWriter::requested_obj_from_buffer_offset(size_t offset) {
193 oop req_obj = cast_to_oop(_requested_bottom + offset);
194 assert(is_in_requested_range(req_obj), "must be");
195 return req_obj;
196 }
197
198 oop AOTMappedHeapWriter::source_obj_to_requested_obj(oop src_obj) {
199 assert(CDSConfig::is_dumping_heap(), "dump-time only");
200 HeapShared::CachedOopInfo* p = HeapShared::get_cached_oop_info(src_obj);
201 if (p != nullptr) {
202 return requested_obj_from_buffer_offset(p->buffer_offset());
203 } else {
204 return nullptr;
205 }
206 }
207
208 oop AOTMappedHeapWriter::buffered_addr_to_source_obj(address buffered_addr) {
209 OopHandle* oh = _buffer_offset_to_source_obj_table->get(buffered_address_to_offset(buffered_addr));
210 if (oh != nullptr) {
211 return oh->resolve();
212 } else {
213 return nullptr;
214 }
215 }
216
217 Klass* AOTMappedHeapWriter::real_klass_of_buffered_oop(address buffered_addr) {
218 oop p = buffered_addr_to_source_obj(buffered_addr);
219 if (p != nullptr) {
220 return p->klass();
221 } else if (get_filler_size_at(buffered_addr) > 0) {
222 return Universe::fillerArrayKlass();
223 } else {
224 // This is one of the root segments
225 return Universe::objectArrayKlass();
226 }
227 }
228
229 size_t AOTMappedHeapWriter::size_of_buffered_oop(address buffered_addr) {
230 oop p = buffered_addr_to_source_obj(buffered_addr);
231 if (p != nullptr) {
232 if (UseCompactObjectHeaders) {
233 // Use the buffered object's mark word to determine size, not the source
234 // object's. The source object's mark word may have changed after the
235 // buffer was written (e.g., it may have been hashed by
236 // make_archived_object_cache_gc_safe), which would cause copy_size_cds
237 // to return a different size than what was actually allocated.
238 // The buffered copy's mark word was set by update_header_for_requested_obj
239 // and correctly reflects the allocated size via its expanded/hash state.
240 oop buffered_oop = cast_to_oop(buffered_addr);
241 markWord buffered_mark = buffered_oop->mark();
242 return buffered_oop->size_given_mark_and_klass(buffered_mark, p->klass());
243 }
244 return p->size();
245 }
246
247 size_t nbytes = get_filler_size_at(buffered_addr);
248 if (nbytes > 0) {
249 assert((nbytes % BytesPerWord) == 0, "should be aligned");
250 return nbytes / BytesPerWord;
251 }
252
253 address hrs = buffer_bottom();
254 for (size_t seg_idx = 0; seg_idx < _heap_root_segments.count(); seg_idx++) {
255 nbytes = _heap_root_segments.size_in_bytes(seg_idx);
256 if (hrs == buffered_addr) {
257 assert((nbytes % BytesPerWord) == 0, "should be aligned");
258 return nbytes / BytesPerWord;
259 }
260 hrs += nbytes;
261 }
262
263 ShouldNotReachHere();
264 return 0;
265 }
266
267 address AOTMappedHeapWriter::buffered_addr_to_requested_addr(address buffered_addr) {
268 return _requested_bottom + buffered_address_to_offset(buffered_addr);
269 }
270
271 address AOTMappedHeapWriter::requested_address() {
272 assert(_buffer != nullptr, "must be initialized");
273 return _requested_bottom;
274 }
275
276 void AOTMappedHeapWriter::allocate_buffer() {
277 int initial_buffer_size = 100000;
278 _buffer = new GrowableArrayCHeap<u1, mtClassShared>(initial_buffer_size);
279 _buffer_used = 0;
280 ensure_buffer_space(1); // so that buffer_bottom() works
281 }
282
283 void AOTMappedHeapWriter::ensure_buffer_space(size_t min_bytes) {
284 // We usually have very small heaps. If we get a huge one it's probably caused by a bug.
285 guarantee(min_bytes <= max_jint, "we dont support archiving more than 2G of objects");
286 _buffer->at_grow(to_array_index(min_bytes));
287 }
288
289 objArrayOop AOTMappedHeapWriter::allocate_root_segment(size_t offset, int element_count) {
290 HeapWord* mem = offset_to_buffered_address<HeapWord *>(offset);
291 memset(mem, 0, objArrayOopDesc::object_size(element_count));
292
293 // The initialization code is copied from MemAllocator::finish and ObjArrayAllocator::initialize.
294 if (UseCompactObjectHeaders) {
295 oopDesc::release_set_mark(mem, Universe::objectArrayKlass()->prototype_header());
296 } else {
297 oopDesc::set_mark(mem, markWord::prototype());
298 oopDesc::release_set_klass(mem, Universe::objectArrayKlass());
299 }
300 arrayOopDesc::set_length(mem, element_count);
301 return objArrayOop(cast_to_oop(mem));
302 }
303
304 void AOTMappedHeapWriter::root_segment_at_put(objArrayOop segment, int index, oop root) {
305 // Do not use arrayOop->obj_at_put(i, o) as arrayOop is outside the real heap!
306 if (UseCompressedOops) {
307 *segment->obj_at_addr<narrowOop>(index) = CompressedOops::encode(root);
308 } else {
309 *segment->obj_at_addr<oop>(index) = root;
310 }
311 }
312
313 void AOTMappedHeapWriter::copy_roots_to_buffer(GrowableArrayCHeap<oop, mtClassShared>* roots) {
314 // Depending on the number of classes we are archiving, a single roots array may be
315 // larger than MIN_GC_REGION_ALIGNMENT. Roots are allocated first in the buffer, which
316 // allows us to chop the large array into a series of "segments". Current layout
317 // starts with zero or more segments exactly fitting MIN_GC_REGION_ALIGNMENT, and end
318 // with a single segment that may be smaller than MIN_GC_REGION_ALIGNMENT.
319 // This is simple and efficient. We do not need filler objects anywhere between the segments,
320 // or immediately after the last segment. This allows starting the object dump immediately
321 // after the roots.
322
323 assert((_buffer_used % MIN_GC_REGION_ALIGNMENT) == 0,
324 "Pre-condition: Roots start at aligned boundary: %zu", _buffer_used);
325
326 int max_elem_count = ((MIN_GC_REGION_ALIGNMENT - arrayOopDesc::header_size_in_bytes()) / heapOopSize);
327 assert(objArrayOopDesc::object_size(max_elem_count)*HeapWordSize == MIN_GC_REGION_ALIGNMENT,
328 "Should match exactly");
329
330 HeapRootSegments segments(_buffer_used,
331 roots->length(),
332 MIN_GC_REGION_ALIGNMENT,
333 max_elem_count);
334
335 int root_index = 0;
336 for (size_t seg_idx = 0; seg_idx < segments.count(); seg_idx++) {
337 int size_elems = segments.size_in_elems(seg_idx);
338 size_t size_bytes = segments.size_in_bytes(seg_idx);
339
340 size_t oop_offset = _buffer_used;
341 _buffer_used = oop_offset + size_bytes;
342 ensure_buffer_space(_buffer_used);
343
344 assert((oop_offset % MIN_GC_REGION_ALIGNMENT) == 0,
345 "Roots segment %zu start is not aligned: %zu",
346 segments.count(), oop_offset);
347
348 objArrayOop seg_oop = allocate_root_segment(oop_offset, size_elems);
349 for (int i = 0; i < size_elems; i++) {
350 root_segment_at_put(seg_oop, i, roots->at(root_index++));
351 }
352
353 log_info(aot, heap)("archived obj root segment [%d] = %zu bytes, obj = " PTR_FORMAT,
354 size_elems, size_bytes, p2i(seg_oop));
355 }
356
357 assert(root_index == roots->length(), "Post-condition: All roots are handled");
358
359 _heap_root_segments = segments;
360 }
361
362 // The goal is to sort the objects in increasing order of:
363 // - objects that have only oop pointers
364 // - objects that have both native and oop pointers
365 // - objects that have only native pointers
366 // - objects that have no pointers
367 static int oop_sorting_rank(oop o) {
368 bool has_oop_ptr, has_native_ptr;
369 HeapShared::get_pointer_info(o, has_oop_ptr, has_native_ptr);
370
371 if (has_oop_ptr) {
372 if (!has_native_ptr) {
373 return 0;
374 } else {
375 return 1;
376 }
377 } else {
378 if (has_native_ptr) {
379 return 2;
380 } else {
381 return 3;
382 }
383 }
384 }
385
386 int AOTMappedHeapWriter::compare_objs_by_oop_fields(HeapObjOrder* a, HeapObjOrder* b) {
387 int rank_a = a->_rank;
388 int rank_b = b->_rank;
389
390 if (rank_a != rank_b) {
391 return rank_a - rank_b;
392 } else {
393 // If they are the same rank, sort them by their position in the _source_objs array
394 return a->_index - b->_index;
395 }
396 }
397
398 void AOTMappedHeapWriter::sort_source_objs() {
399 log_info(aot)("sorting heap objects");
400 int len = _source_objs->length();
401 _source_objs_order = new GrowableArrayCHeap<HeapObjOrder, mtClassShared>(len);
402
403 for (int i = 0; i < len; i++) {
404 oop o = _source_objs->at(i);
405 int rank = oop_sorting_rank(o);
406 HeapObjOrder os = {i, rank};
407 _source_objs_order->append(os);
408 }
409 log_info(aot)("computed ranks");
410 _source_objs_order->sort(compare_objs_by_oop_fields);
411 log_info(aot)("sorting heap objects done");
412 }
413
414 void AOTMappedHeapWriter::copy_source_objs_to_buffer(GrowableArrayCHeap<oop, mtClassShared>* roots) {
415 // There could be multiple root segments, which we want to be aligned by region.
416 // Putting them ahead of objects makes sure we waste no space.
417 copy_roots_to_buffer(roots);
418
419 sort_source_objs();
420 for (int i = 0; i < _source_objs_order->length(); i++) {
421 int src_obj_index = _source_objs_order->at(i)._index;
422 oop src_obj = _source_objs->at(src_obj_index);
423 HeapShared::CachedOopInfo* info = HeapShared::get_cached_oop_info(src_obj);
424 assert(info != nullptr, "must be");
425 size_t buffer_offset = copy_one_source_obj_to_buffer(src_obj);
426 info->set_buffer_offset(buffer_offset);
427 assert(buffer_offset <= 0x7fffffff, "sanity");
428
429 OopHandle handle(Universe::vm_global(), src_obj);
430 _buffer_offset_to_source_obj_table->put_when_absent(buffer_offset, handle);
431 _buffer_offset_to_source_obj_table->maybe_grow();
432
433 if (java_lang_Module::is_instance(src_obj)) {
434 Modules::check_archived_module_oop(src_obj);
435 }
436 }
437
438 log_info(aot)("Size of heap region = %zu bytes, %d objects, %d roots, %d native ptrs",
439 _buffer_used, _source_objs->length() + 1, roots->length(), _num_native_ptrs);
440 log_info(aot)(" strings = %8zu (%zu bytes)", _num_strings, _string_bytes);
441 log_info(aot)(" packages = %8zu", _num_packages);
442 log_info(aot)(" protection domains = %8zu", _num_protection_domains);
443 }
444
445 size_t AOTMappedHeapWriter::filler_array_byte_size(int length) {
446 size_t byte_size = objArrayOopDesc::object_size(length) * HeapWordSize;
447 return byte_size;
448 }
449
450 int AOTMappedHeapWriter::filler_array_length(size_t fill_bytes) {
451 assert(is_object_aligned(fill_bytes), "must be");
452 size_t elemSize = (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop));
453
454 int initial_length = to_array_length(fill_bytes / elemSize);
455 for (int length = initial_length; length >= 0; length --) {
456 size_t array_byte_size = filler_array_byte_size(length);
457 if (array_byte_size == fill_bytes) {
458 return length;
459 }
460 }
461
462 ShouldNotReachHere();
463 return -1;
464 }
465
466 HeapWord* AOTMappedHeapWriter::init_filler_array_at_buffer_top(int array_length, size_t fill_bytes) {
467 Klass* oak = Universe::objectArrayKlass(); // already relocated to point to archived klass
468 HeapWord* mem = offset_to_buffered_address<HeapWord*>(_buffer_used);
469 memset(mem, 0, fill_bytes);
470 narrowKlass nk = ArchiveBuilder::current()->get_requested_narrow_klass(oak);
471 if (UseCompactObjectHeaders) {
472 oopDesc::release_set_mark(mem, markWord::prototype().set_narrow_klass(nk));
473 } else {
474 oopDesc::set_mark(mem, markWord::prototype());
475 cast_to_oop(mem)->set_narrow_klass(nk);
476 }
477 arrayOopDesc::set_length(mem, array_length);
478 return mem;
479 }
480
481 void AOTMappedHeapWriter::maybe_fill_gc_region_gap(size_t required_byte_size) {
482 // We fill only with arrays (so we don't need to use a single HeapWord filler if the
483 // leftover space is smaller than a zero-sized array object). Therefore, we need to
484 // make sure there's enough space of min_filler_byte_size in the current region after
485 // required_byte_size has been allocated. If not, fill the remainder of the current
486 // region.
487 size_t min_filler_byte_size = filler_array_byte_size(0);
488 size_t new_used = _buffer_used + required_byte_size + min_filler_byte_size;
489
490 const size_t cur_min_region_bottom = align_down(_buffer_used, MIN_GC_REGION_ALIGNMENT);
491 const size_t next_min_region_bottom = align_down(new_used, MIN_GC_REGION_ALIGNMENT);
492
493 if (cur_min_region_bottom != next_min_region_bottom) {
494 // Make sure that no objects span across MIN_GC_REGION_ALIGNMENT. This way
495 // we can map the region in any region-based collector.
496 assert(next_min_region_bottom > cur_min_region_bottom, "must be");
497 assert(next_min_region_bottom - cur_min_region_bottom == MIN_GC_REGION_ALIGNMENT,
498 "no buffered object can be larger than %d bytes", MIN_GC_REGION_ALIGNMENT);
499
500 const size_t filler_end = next_min_region_bottom;
501 const size_t fill_bytes = filler_end - _buffer_used;
502 assert(fill_bytes > 0, "must be");
503 ensure_buffer_space(filler_end);
504
505 int array_length = filler_array_length(fill_bytes);
506 log_info(aot, heap)("Inserting filler obj array of %d elements (%zu bytes total) @ buffer offset %zu",
507 array_length, fill_bytes, _buffer_used);
508 HeapWord* filler = init_filler_array_at_buffer_top(array_length, fill_bytes);
509 _buffer_used = filler_end;
510 _fillers->put(buffered_address_to_offset((address)filler), fill_bytes);
511 }
512 }
513
514 size_t AOTMappedHeapWriter::get_filler_size_at(address buffered_addr) {
515 size_t* p = _fillers->get(buffered_address_to_offset(buffered_addr));
516 if (p != nullptr) {
517 assert(*p > 0, "filler must be larger than zero bytes");
518 return *p;
519 } else {
520 return 0; // buffered_addr is not a filler
521 }
522 }
523
524 template <typename T>
525 void update_buffered_object_field(address buffered_obj, int field_offset, T value) {
526 T* field_addr = cast_to_oop(buffered_obj)->field_addr<T>(field_offset);
527 *field_addr = value;
528 }
529
530 void AOTMappedHeapWriter::update_stats(oop src_obj) {
531 if (java_lang_String::is_instance(src_obj)) {
532 _num_strings ++;
533 _string_bytes += src_obj->size() * HeapWordSize;
534 _string_bytes += java_lang_String::value(src_obj)->size() * HeapWordSize;
535 } else {
536 Klass* k = src_obj->klass();
537 Symbol* name = k->name();
538 if (name->equals("java/lang/NamedPackage") || name->equals("java/lang/Package")) {
539 _num_packages ++;
540 } else if (name->equals("java/security/ProtectionDomain")) {
541 _num_protection_domains ++;
542 }
543 }
544 }
545
546 size_t AOTMappedHeapWriter::copy_one_source_obj_to_buffer(oop src_obj) {
547 update_stats(src_obj);
548
549 assert(!is_too_large_to_archive(src_obj), "already checked");
550 size_t old_size = src_obj->size();
551 size_t new_size = src_obj->copy_size_cds(old_size, src_obj->mark());
552 size_t byte_size = new_size * HeapWordSize;
553 assert(byte_size > 0, "no zero-size objects");
554
555 // For region-based collectors such as G1, the archive heap may be mapped into
556 // multiple regions. We need to make sure that we don't have an object that can possible
557 // span across two regions.
558 maybe_fill_gc_region_gap(byte_size);
559
560 size_t new_used = _buffer_used + byte_size;
561 assert(new_used > _buffer_used, "no wrap around");
562
563 size_t cur_min_region_bottom = align_down(_buffer_used, MIN_GC_REGION_ALIGNMENT);
564 size_t next_min_region_bottom = align_down(new_used, MIN_GC_REGION_ALIGNMENT);
565 assert(cur_min_region_bottom == next_min_region_bottom, "no object should cross minimal GC region boundaries");
566
567 ensure_buffer_space(new_used);
568
569 address from = cast_from_oop<address>(src_obj);
570 address to = offset_to_buffered_address<address>(_buffer_used);
571 assert(is_object_aligned(_buffer_used), "sanity");
572 assert(is_object_aligned(byte_size), "sanity");
573 memcpy(to, from, MIN2(new_size, old_size) * HeapWordSize);
574
575 // These native pointers will be restored explicitly at run time.
576 if (java_lang_Module::is_instance(src_obj)) {
577 update_buffered_object_field<ModuleEntry*>(to, java_lang_Module::module_entry_offset(), nullptr);
578 } else if (java_lang_ClassLoader::is_instance(src_obj)) {
579 #ifdef ASSERT
580 // We only archive these loaders
581 if (src_obj != SystemDictionary::java_platform_loader() &&
582 src_obj != SystemDictionary::java_system_loader()) {
583 assert(src_obj->klass()->name()->equals("jdk/internal/loader/ClassLoaders$BootClassLoader"), "must be");
584 }
585 #endif
586 update_buffered_object_field<ClassLoaderData*>(to, java_lang_ClassLoader::loader_data_offset(), nullptr);
587 }
588
589 size_t buffered_obj_offset = _buffer_used;
590 _buffer_used = new_used;
591
592 return buffered_obj_offset;
593 }
594
595 // Set the range [_requested_bottom, _requested_top), the requested address range of all
596 // the archived heap objects in the production run.
597 //
598 // (1) UseCompressedOops == true && !is_writing_deterministic_heap()
599 //
600 // The archived objects are stored using the COOPS encoding of the assembly phase.
601 // We pick a range within the heap used by the assembly phase.
602 //
603 // In the production run, if different COOPS encodings are used:
604 // - The heap contents needs to be relocated.
605 //
606 // (2) UseCompressedOops == true && is_writing_deterministic_heap()
607 //
608 // We always use zero-based, zero-shift encoding. _requested_top is aligned to 0x10000000.
609 //
610 // (3) UseCompressedOops == false:
611 //
612 // In the production run, the heap range is usually picked (randomly) by the OS, so we
613 // will almost always need to perform relocation, regardless of how we pick the requested
614 // address range.
615 //
616 // So we just hard code it to NOCOOPS_REQUESTED_BASE.
617 //
618 void AOTMappedHeapWriter::set_requested_address_range(AOTMappedHeapInfo* info) {
619 assert(!info->is_used(), "only set once");
620
621 size_t heap_region_byte_size = _buffer_used;
622 assert(heap_region_byte_size > 0, "must archived at least one object!");
623
624 if (UseCompressedOops) {
625 if (is_writing_deterministic_heap()) {
626 // Pick a heap range so that requested addresses can be encoded with zero-base/no shift.
627 // We align the requested bottom to at least 1 MB: if the production run uses G1 with a small
628 // heap (e.g., -Xmx256m), it's likely that we can map the archived objects at the
629 // requested location to avoid relocation.
630 //
631 // For other collectors or larger heaps, relocation is unavoidable, but is usually
632 // quite cheap. If you really want to avoid relocation, use the AOT workflow instead.
633 address heap_end = (address)0x100000000;
634 size_t alignment = MAX2(MIN_GC_REGION_ALIGNMENT, 1024 * 1024);
635 if (align_up(heap_region_byte_size, alignment) >= (size_t)heap_end) {
636 log_error(aot, heap)("cached heap space is too large: %zu bytes", heap_region_byte_size);
637 AOTMetaspace::unrecoverable_writing_error();
638 }
639 _requested_bottom = align_down(heap_end - heap_region_byte_size, alignment);
640 } else if (UseG1GC) {
641 // For G1, pick the range at the top of the current heap. If the exact same heap sizes
642 // are used in the production run, it's likely that we can map the archived objects
643 // at the requested location to avoid relocation.
644 address heap_end = (address)G1CollectedHeap::heap()->reserved().end();
645 log_info(aot, heap)("Heap end = %p", heap_end);
646 _requested_bottom = align_down(heap_end - heap_region_byte_size, G1HeapRegion::GrainBytes);
647 _requested_bottom = align_down(_requested_bottom, MIN_GC_REGION_ALIGNMENT);
648 assert(is_aligned(_requested_bottom, G1HeapRegion::GrainBytes), "sanity");
649 } else {
650 _requested_bottom = align_up(CompressedOops::begin(), MIN_GC_REGION_ALIGNMENT);
651 }
652 } else {
653 // We always write the objects as if the heap started at this address. This
654 // makes the contents of the archive heap deterministic.
655 //
656 // Note that at runtime, the heap address is selected by the OS, so the archive
657 // heap will not be mapped at 0x10000000, and the contents need to be patched.
658 _requested_bottom = align_up((address)NOCOOPS_REQUESTED_BASE, MIN_GC_REGION_ALIGNMENT);
659 }
660
661 assert(is_aligned(_requested_bottom, MIN_GC_REGION_ALIGNMENT), "sanity");
662
663 _requested_top = _requested_bottom + _buffer_used;
664
665 info->set_buffer_region(MemRegion(offset_to_buffered_address<HeapWord*>(0),
666 offset_to_buffered_address<HeapWord*>(_buffer_used)));
667 info->set_root_segments(_heap_root_segments);
668 }
669
670 // Oop relocation
671
672 template <typename T> T* AOTMappedHeapWriter::requested_addr_to_buffered_addr(T* p) {
673 assert(is_in_requested_range(cast_to_oop(p)), "must be");
674
675 address addr = address(p);
676 assert(addr >= _requested_bottom, "must be");
677 size_t offset = addr - _requested_bottom;
678 return offset_to_buffered_address<T*>(offset);
679 }
680
681 template <typename T> oop AOTMappedHeapWriter::load_source_oop_from_buffer(T* buffered_addr) {
682 oop o = load_oop_from_buffer(buffered_addr);
683 assert(!in_buffer(cast_from_oop<address>(o)), "must point to source oop");
684 return o;
685 }
686
687 template <typename T> void AOTMappedHeapWriter::store_requested_oop_in_buffer(T* buffered_addr,
688 oop request_oop) {
689 assert(request_oop == nullptr || is_in_requested_range(request_oop), "must be");
690 store_oop_in_buffer(buffered_addr, request_oop);
691 }
692
693 inline void AOTMappedHeapWriter::store_oop_in_buffer(oop* buffered_addr, oop requested_obj) {
694 *buffered_addr = requested_obj;
695 }
696
697 inline void AOTMappedHeapWriter::store_oop_in_buffer(narrowOop* buffered_addr, oop requested_obj) {
698 narrowOop val = CompressedOops::encode(requested_obj);
699 *buffered_addr = val;
700 }
701
702 oop AOTMappedHeapWriter::load_oop_from_buffer(oop* buffered_addr) {
703 return *buffered_addr;
704 }
705
706 oop AOTMappedHeapWriter::load_oop_from_buffer(narrowOop* buffered_addr) {
707 return CompressedOops::decode(*buffered_addr);
708 }
709
710 template <typename T> void AOTMappedHeapWriter::relocate_field_in_buffer(T* field_addr_in_buffer, oop source_referent, CHeapBitMap* oopmap) {
711 oop request_referent = source_obj_to_requested_obj(source_referent);
712 if (UseCompressedOops && is_writing_deterministic_heap()) {
713 // We use zero-based, 0-shift encoding, so the narrowOop is just the lower
714 // 32 bits of request_referent
715 intptr_t addr = cast_from_oop<intptr_t>(request_referent);
716 *((narrowOop*)field_addr_in_buffer) = CompressedOops::narrow_oop_cast(addr);
717 } else {
718 store_requested_oop_in_buffer<T>(field_addr_in_buffer, request_referent);
719 }
720 if (request_referent != nullptr) {
721 mark_oop_pointer<T>(field_addr_in_buffer, oopmap);
722 }
723 }
724
725 template <typename T> void AOTMappedHeapWriter::mark_oop_pointer(T* buffered_addr, CHeapBitMap* oopmap) {
726 T* request_p = (T*)(buffered_addr_to_requested_addr((address)buffered_addr));
727 address requested_region_bottom;
728
729 assert(request_p >= (T*)_requested_bottom, "sanity");
730 assert(request_p < (T*)_requested_top, "sanity");
731 requested_region_bottom = _requested_bottom;
732
733 // Mark the pointer in the oopmap
734 T* region_bottom = (T*)requested_region_bottom;
735 assert(request_p >= region_bottom, "must be");
736 BitMap::idx_t idx = request_p - region_bottom;
737 assert(idx < oopmap->size(), "overflow");
738 oopmap->set_bit(idx);
739 }
740
741 void AOTMappedHeapWriter::update_header_for_requested_obj(oop requested_obj, oop src_obj, Klass* src_klass) {
742 narrowKlass nk = ArchiveBuilder::current()->get_requested_narrow_klass(src_klass);
743 address buffered_addr = requested_addr_to_buffered_addr(cast_from_oop<address>(requested_obj));
744
745 oop fake_oop = cast_to_oop(buffered_addr);
746 if (UseCompactObjectHeaders) {
747 fake_oop->set_mark(markWord::prototype().set_narrow_klass(nk));
748 assert(fake_oop->mark().narrow_klass() != 0, "must not be null");
749 } else {
750 fake_oop->set_narrow_klass(nk);
751 }
752
753 if (src_obj == nullptr) {
754 return;
755 }
756 // We need to retain the identity_hash, because it may have been used by some hashtables
757 // in the shared heap.
758 if (!src_obj->fast_no_hash_check()) {
759 intptr_t src_hash = src_obj->identity_hash();
760 if (UseCompactObjectHeaders) {
761 markWord m = markWord::prototype().set_narrow_klass(nk);
762 m = m.copy_hashctrl_from(src_obj->mark());
763 fake_oop->set_mark(m);
764 if (m.is_hashed_not_expanded()) {
765 fake_oop->set_mark(fake_oop->initialize_hash_if_necessary(src_obj, src_klass, m));
766 } else if (m.is_not_hashed_expanded()) {
767 fake_oop->set_mark(m.set_not_hashed_not_expanded());
768 }
769 assert(!fake_oop->mark().is_not_hashed_expanded() && !fake_oop->mark().is_hashed_not_expanded(), "must not be not-hashed-moved and not be hashed-not-moved");
770 } else {
771 fake_oop->set_mark(markWord::prototype().copy_set_hash(src_hash));
772 DEBUG_ONLY(intptr_t archived_hash = fake_oop->identity_hash());
773 assert(src_hash == archived_hash, "Different hash codes: original " INTPTR_FORMAT ", archived " INTPTR_FORMAT, src_hash, archived_hash);
774 }
775 assert(fake_oop->mark().is_unlocked(), "sanity");
776 }
777 // Strip age bits.
778 fake_oop->set_mark(fake_oop->mark().set_age(0));
779 }
780
781 class AOTMappedHeapWriter::EmbeddedOopRelocator: public BasicOopIterateClosure {
782 oop _src_obj;
783 address _buffered_obj;
784 CHeapBitMap* _oopmap;
785 bool _is_java_lang_ref;
786 public:
787 EmbeddedOopRelocator(oop src_obj, address buffered_obj, CHeapBitMap* oopmap) :
788 _src_obj(src_obj), _buffered_obj(buffered_obj), _oopmap(oopmap)
789 {
790 _is_java_lang_ref = AOTReferenceObjSupport::check_if_ref_obj(src_obj);
791 }
792
793 void do_oop(narrowOop *p) { EmbeddedOopRelocator::do_oop_work(p); }
794 void do_oop( oop *p) { EmbeddedOopRelocator::do_oop_work(p); }
795
796 private:
797 template <class T> void do_oop_work(T *p) {
798 int field_offset = pointer_delta_as_int((char*)p, cast_from_oop<char*>(_src_obj));
799 T* field_addr = (T*)(_buffered_obj + field_offset);
800 oop referent = load_source_oop_from_buffer<T>(field_addr);
801 referent = HeapShared::maybe_remap_referent(_is_java_lang_ref, field_offset, referent);
802 AOTMappedHeapWriter::relocate_field_in_buffer<T>(field_addr, referent, _oopmap);
803 }
804 };
805
806 static void log_bitmap_usage(const char* which, BitMap* bitmap, size_t total_bits) {
807 // The whole heap is covered by total_bits, but there are only non-zero bits within [start ... end).
808 size_t start = bitmap->find_first_set_bit(0);
809 size_t end = bitmap->size();
810 log_info(aot)("%s = %7zu ... %7zu (%3zu%% ... %3zu%% = %3zu%%)", which,
811 start, end,
812 start * 100 / total_bits,
813 end * 100 / total_bits,
814 (end - start) * 100 / total_bits);
815 }
816
817 // Update all oop fields embedded in the buffered objects
818 void AOTMappedHeapWriter::relocate_embedded_oops(GrowableArrayCHeap<oop, mtClassShared>* roots,
819 AOTMappedHeapInfo* heap_info) {
820 size_t oopmap_unit = (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop));
821 size_t heap_region_byte_size = _buffer_used;
822 heap_info->oopmap()->resize(heap_region_byte_size / oopmap_unit);
823
824 for (int i = 0; i < _source_objs_order->length(); i++) {
825 int src_obj_index = _source_objs_order->at(i)._index;
826 oop src_obj = _source_objs->at(src_obj_index);
827 HeapShared::CachedOopInfo* info = HeapShared::get_cached_oop_info(src_obj);
828 assert(info != nullptr, "must be");
829 oop requested_obj = requested_obj_from_buffer_offset(info->buffer_offset());
830 update_header_for_requested_obj(requested_obj, src_obj, src_obj->klass());
831 address buffered_obj = offset_to_buffered_address<address>(info->buffer_offset());
832 EmbeddedOopRelocator relocator(src_obj, buffered_obj, heap_info->oopmap());
833 src_obj->oop_iterate(&relocator);
834 mark_native_pointers(src_obj);
835 };
836
837 // Relocate HeapShared::roots(), which is created in copy_roots_to_buffer() and
838 // doesn't have a corresponding src_obj, so we can't use EmbeddedOopRelocator on it.
839 for (size_t seg_idx = 0; seg_idx < _heap_root_segments.count(); seg_idx++) {
840 size_t seg_offset = _heap_root_segments.segment_offset(seg_idx);
841
842 objArrayOop requested_obj = (objArrayOop)requested_obj_from_buffer_offset(seg_offset);
843 update_header_for_requested_obj(requested_obj, nullptr, Universe::objectArrayKlass());
844 address buffered_obj = offset_to_buffered_address<address>(seg_offset);
845 int length = _heap_root_segments.size_in_elems(seg_idx);
846
847 size_t elem_size = UseCompressedOops ? sizeof(narrowOop) : sizeof(oop);
848
849 for (int i = 0; i < length; i++) {
850 // There is no source object; these are native oops - load, translate and
851 // write back
852 size_t elem_offset = objArrayOopDesc::base_offset_in_bytes() + elem_size * i;
853 HeapWord* elem_addr = (HeapWord*)(buffered_obj + elem_offset);
854 oop obj = NativeAccess<>::oop_load(elem_addr);
855 obj = HeapShared::maybe_remap_referent(false /* is_reference_field */, elem_offset, obj);
856 if (UseCompressedOops) {
857 relocate_field_in_buffer<narrowOop>((narrowOop*)elem_addr, obj, heap_info->oopmap());
858 } else {
859 relocate_field_in_buffer<oop>((oop*)elem_addr, obj, heap_info->oopmap());
860 }
861 }
862 }
863
864 compute_ptrmap(heap_info);
865
866 size_t total_bytes = (size_t)_buffer->length();
867 log_bitmap_usage("oopmap", heap_info->oopmap(), total_bytes / (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop)));
868 log_bitmap_usage("ptrmap", heap_info->ptrmap(), total_bytes / sizeof(address));
869 }
870
871 void AOTMappedHeapWriter::mark_native_pointer(oop src_obj, int field_offset) {
872 Metadata* ptr = src_obj->metadata_field_acquire(field_offset);
873 if (ptr != nullptr) {
874 NativePointerInfo info;
875 info._src_obj = src_obj;
876 info._field_offset = field_offset;
877 _native_pointers->append(info);
878 HeapShared::set_has_native_pointers(src_obj);
879 _num_native_ptrs ++;
880 }
881 }
882
883 void AOTMappedHeapWriter::mark_native_pointers(oop orig_obj) {
884 HeapShared::do_metadata_offsets(orig_obj, [&](int offset) {
885 mark_native_pointer(orig_obj, offset);
886 });
887 }
888
889 void AOTMappedHeapWriter::compute_ptrmap(AOTMappedHeapInfo* heap_info) {
890 int num_non_null_ptrs = 0;
891 Metadata** bottom = (Metadata**) _requested_bottom;
892 Metadata** top = (Metadata**) _requested_top; // exclusive
893 heap_info->ptrmap()->resize(top - bottom);
894
895 BitMap::idx_t max_idx = 32; // paranoid - don't make it too small
896 for (int i = 0; i < _native_pointers->length(); i++) {
897 NativePointerInfo info = _native_pointers->at(i);
898 oop src_obj = info._src_obj;
899 int field_offset = info._field_offset;
900 HeapShared::CachedOopInfo* p = HeapShared::get_cached_oop_info(src_obj);
901 // requested_field_addr = the address of this field in the requested space
902 oop requested_obj = requested_obj_from_buffer_offset(p->buffer_offset());
903 Metadata** requested_field_addr = (Metadata**)(cast_from_oop<address>(requested_obj) + field_offset);
904 assert(bottom <= requested_field_addr && requested_field_addr < top, "range check");
905
906 // Mark this field in the bitmap
907 BitMap::idx_t idx = requested_field_addr - bottom;
908 heap_info->ptrmap()->set_bit(idx);
909 num_non_null_ptrs ++;
910 max_idx = MAX2(max_idx, idx);
911
912 // Set the native pointer to the requested address of the metadata (at runtime, the metadata will have
913 // this address if the RO/RW regions are mapped at the default location).
914
915 Metadata** buffered_field_addr = requested_addr_to_buffered_addr(requested_field_addr);
916 Metadata* native_ptr = *buffered_field_addr;
917 guarantee(native_ptr != nullptr, "sanity");
918
919 if (RegeneratedClasses::has_been_regenerated(native_ptr)) {
920 native_ptr = RegeneratedClasses::get_regenerated_object(native_ptr);
921 }
922
923 if (!ArchiveBuilder::current()->has_been_archived((address)native_ptr)) {
924 ResourceMark rm;
925 LogStreamHandle(Error, aot) log;
926 log.print("Marking native pointer for oop %p (type = %s, offset = %d)",
927 cast_from_oop<void*>(src_obj), src_obj->klass()->external_name(), field_offset);
928 src_obj->print_on(&log);
929 fatal("Metadata %p should have been archived", native_ptr);
930 }
931
932 address buffered_native_ptr = ArchiveBuilder::current()->get_buffered_addr((address)native_ptr);
933 address requested_native_ptr = ArchiveBuilder::current()->to_requested(buffered_native_ptr);
934 *buffered_field_addr = (Metadata*)requested_native_ptr;
935 }
936
937 heap_info->ptrmap()->resize(max_idx + 1);
938 log_info(aot, heap)("calculate_ptrmap: marked %d non-null native pointers for heap region (%zu bits)",
939 num_non_null_ptrs, size_t(heap_info->ptrmap()->size()));
940 }
941
942 AOTMapLogger::OopDataIterator* AOTMappedHeapWriter::oop_iterator(AOTMappedHeapInfo* heap_info) {
943 class MappedWriterOopIterator : public AOTMappedHeapOopIterator {
944 public:
945 MappedWriterOopIterator(address buffer_start,
946 address buffer_end,
947 address requested_base,
948 address requested_start,
949 int requested_shift,
950 size_t num_root_segments) :
951 AOTMappedHeapOopIterator(buffer_start,
952 buffer_end,
953 requested_base,
954 requested_start,
955 requested_shift,
956 num_root_segments) {}
957
958 AOTMapLogger::OopData capture(address buffered_addr) override {
959 oopDesc* raw_oop = (oopDesc*)buffered_addr;
960 size_t size = size_of_buffered_oop(buffered_addr);
961 address requested_addr = buffered_addr_to_requested_addr(buffered_addr);
962 intptr_t target_location = (intptr_t)requested_addr;
963 uint64_t pd = (uint64_t)(pointer_delta(buffered_addr, _buffer_start, 1));
964 uint32_t narrow_location = checked_cast<uint32_t>(_buffer_start_narrow_oop + (pd >> _requested_shift));
965 Klass* klass = real_klass_of_buffered_oop(buffered_addr);
966
967 return { buffered_addr,
968 requested_addr,
969 target_location,
970 narrow_location,
971 raw_oop,
972 klass,
973 size,
974 false };
975 }
976 };
977
978 MemRegion r = heap_info->buffer_region();
979 address buffer_start = address(r.start());
980 address buffer_end = address(r.end());
981
982 address requested_base = UseCompressedOops ? AOTMappedHeapWriter::narrow_oop_base() : (address)AOTMappedHeapWriter::NOCOOPS_REQUESTED_BASE;
983 address requested_start = UseCompressedOops ? AOTMappedHeapWriter::buffered_addr_to_requested_addr(buffer_start) : requested_base;
984 int requested_shift = AOTMappedHeapWriter::narrow_oop_shift();
985
986 return new MappedWriterOopIterator(buffer_start,
987 buffer_end,
988 requested_base,
989 requested_start,
990 requested_shift,
991 heap_info->root_segments().count());
992 }
993
994 #endif // INCLUDE_CDS_JAVA_HEAP