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