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 static size_t _num_strings = 0;
69 static size_t _string_bytes = 0;
70 static size_t _num_packages = 0;
71 static size_t _num_protection_domains = 0;
72
73 GrowableArrayCHeap<AOTMappedHeapWriter::NativePointerInfo, mtClassShared>* AOTMappedHeapWriter::_native_pointers;
74 GrowableArrayCHeap<oop, mtClassShared>* AOTMappedHeapWriter::_source_objs;
75 GrowableArrayCHeap<AOTMappedHeapWriter::HeapObjOrder, mtClassShared>* AOTMappedHeapWriter::_source_objs_order;
76
77 AOTMappedHeapWriter::BufferOffsetToSourceObjectTable*
78 AOTMappedHeapWriter::_buffer_offset_to_source_obj_table = nullptr;
79
80 typedef HashTable<
81 size_t, // offset of a filler from AOTMappedHeapWriter::buffer_bottom()
82 size_t, // size of this filler (in bytes)
83 127, // prime number
84 AnyObj::C_HEAP,
85 mtClassShared> FillersTable;
86 static FillersTable* _fillers;
87 static int _num_native_ptrs = 0;
88
89 void AOTMappedHeapWriter::init() {
90 if (CDSConfig::is_dumping_heap()) {
91 Universe::heap()->collect(GCCause::_java_lang_system_gc);
92
93 _buffer_offset_to_source_obj_table = new (mtClassShared) BufferOffsetToSourceObjectTable(/*size (prime)*/36137, /*max size*/1 * M);
94 _fillers = new (mtClassShared) FillersTable();
95 _requested_bottom = nullptr;
96 _requested_top = nullptr;
97
98 _native_pointers = new GrowableArrayCHeap<NativePointerInfo, mtClassShared>(2048);
99 _source_objs = new GrowableArrayCHeap<oop, mtClassShared>(10000);
100
101 guarantee(MIN_GC_REGION_ALIGNMENT <= G1HeapRegion::min_region_size_in_words() * HeapWordSize, "must be");
102
103 if (CDSConfig::old_cds_flags_used()) {
104 // With the old CDS workflow, we can guatantee determninistic output: given
105 // the same classlist file, we can generate the same static CDS archive.
106 // To ensure determinism, we always use the same compressed oop encoding
107 // (zero-based, no shift). See set_requested_address_range().
108 _is_writing_deterministic_heap = true;
109 } else {
110 // Determninistic output is not supported by the new AOT workflow, so
111 // we don't force the (zero-based, no shift) encoding. This way, it is more
112 // likely that we can avoid oop relocation in the production run.
113 _is_writing_deterministic_heap = false;
114 }
115 }
116 }
117
118 // For AOTMappedHeapWriter::narrow_oop_{mode, base, shift}(), see comments
119 // in AOTMappedHeapWriter::set_requested_address_range(),
120 CompressedOops::Mode AOTMappedHeapWriter::narrow_oop_mode() {
121 if (is_writing_deterministic_heap()) {
122 return CompressedOops::UnscaledNarrowOop;
123 } else {
124 return CompressedOops::mode();
125 }
126 }
127
128 address AOTMappedHeapWriter::narrow_oop_base() {
129 if (is_writing_deterministic_heap()) {
130 return nullptr;
131 } else {
132 return CompressedOops::base();
133 }
134 }
135
136 int AOTMappedHeapWriter::narrow_oop_shift() {
137 if (is_writing_deterministic_heap()) {
138 return 0;
139 } else {
140 return CompressedOops::shift();
141 }
142 }
143
144 void AOTMappedHeapWriter::delete_tables_with_raw_oops() {
145 delete _source_objs;
146 _source_objs = nullptr;
147 }
148
149 void AOTMappedHeapWriter::add_source_obj(oop src_obj) {
150 _source_objs->append(src_obj);
151 }
152
153 void AOTMappedHeapWriter::write(GrowableArrayCHeap<oop, mtClassShared>* roots,
154 AOTMappedHeapInfo* heap_info) {
155 assert(CDSConfig::is_dumping_heap(), "sanity");
156 allocate_buffer();
157 copy_source_objs_to_buffer(roots);
158 set_requested_address_range(heap_info);
159 relocate_embedded_oops(roots, heap_info);
160 }
161
162 bool AOTMappedHeapWriter::is_too_large_to_archive(oop o) {
163 return is_too_large_to_archive(o->size());
164 }
165
166 bool AOTMappedHeapWriter::is_string_too_large_to_archive(oop string) {
167 typeArrayOop value = java_lang_String::value_no_keepalive(string);
168 return is_too_large_to_archive(value);
169 }
170
171 bool AOTMappedHeapWriter::is_too_large_to_archive(size_t size) {
172 assert(size > 0, "no zero-size object");
173 assert(size * HeapWordSize > size, "no overflow");
174 static_assert(MIN_GC_REGION_ALIGNMENT > 0, "must be positive");
175
176 size_t byte_size = size * HeapWordSize;
177 if (byte_size > size_t(MIN_GC_REGION_ALIGNMENT)) {
178 return true;
179 } else {
180 return false;
181 }
182 }
183
184 // Various lookup functions between source_obj, buffered_obj and requested_obj
185 bool AOTMappedHeapWriter::is_in_requested_range(oop o) {
186 assert(_requested_bottom != nullptr, "do not call before _requested_bottom is initialized");
187 address a = cast_from_oop<address>(o);
188 return (_requested_bottom <= a && a < _requested_top);
189 }
190
191 oop AOTMappedHeapWriter::requested_obj_from_buffer_offset(size_t offset) {
192 oop req_obj = cast_to_oop(_requested_bottom + offset);
193 assert(is_in_requested_range(req_obj), "must be");
194 return req_obj;
195 }
196
197 oop AOTMappedHeapWriter::source_obj_to_requested_obj(oop src_obj) {
198 assert(CDSConfig::is_dumping_heap(), "dump-time only");
199 HeapShared::CachedOopInfo* p = HeapShared::get_cached_oop_info(src_obj);
200 if (p != nullptr) {
201 return requested_obj_from_buffer_offset(p->buffer_offset());
202 } else {
203 return nullptr;
204 }
205 }
206
207 oop AOTMappedHeapWriter::buffered_addr_to_source_obj(address buffered_addr) {
208 OopHandle* oh = _buffer_offset_to_source_obj_table->get(buffered_address_to_offset(buffered_addr));
209 if (oh != nullptr) {
210 return oh->resolve();
211 } else {
212 return nullptr;
213 }
214 }
215
216 Klass* AOTMappedHeapWriter::real_klass_of_buffered_oop(address buffered_addr) {
217 oop p = buffered_addr_to_source_obj(buffered_addr);
218 if (p != nullptr) {
219 return p->klass();
220 } else if (get_filler_size_at(buffered_addr) > 0) {
221 return Universe::fillerArrayKlass();
222 } else {
223 // This is one of the root segments
224 return Universe::objectArrayKlass();
225 }
226 }
227
228 size_t AOTMappedHeapWriter::size_of_buffered_oop(address buffered_addr) {
229 oop p = buffered_addr_to_source_obj(buffered_addr);
230 if (p != nullptr) {
231 return p->size();
232 }
233
234 size_t nbytes = get_filler_size_at(buffered_addr);
235 if (nbytes > 0) {
236 assert((nbytes % BytesPerWord) == 0, "should be aligned");
237 return nbytes / BytesPerWord;
238 }
239
240 address hrs = buffer_bottom();
241 for (size_t seg_idx = 0; seg_idx < _heap_root_segments.count(); seg_idx++) {
242 nbytes = _heap_root_segments.size_in_bytes(seg_idx);
243 if (hrs == buffered_addr) {
244 assert((nbytes % BytesPerWord) == 0, "should be aligned");
245 return nbytes / BytesPerWord;
246 }
247 hrs += nbytes;
248 }
249
250 ShouldNotReachHere();
251 return 0;
252 }
253
254 address AOTMappedHeapWriter::buffered_addr_to_requested_addr(address buffered_addr) {
255 return _requested_bottom + buffered_address_to_offset(buffered_addr);
256 }
257
258 address AOTMappedHeapWriter::requested_address() {
259 assert(_buffer != nullptr, "must be initialized");
260 return _requested_bottom;
261 }
262
263 void AOTMappedHeapWriter::allocate_buffer() {
264 int initial_buffer_size = 100000;
265 _buffer = new GrowableArrayCHeap<u1, mtClassShared>(initial_buffer_size);
266 _buffer_used = 0;
267 ensure_buffer_space(1); // so that buffer_bottom() works
268 }
269
270 void AOTMappedHeapWriter::ensure_buffer_space(size_t min_bytes) {
271 // We usually have very small heaps. If we get a huge one it's probably caused by a bug.
272 guarantee(min_bytes <= max_jint, "we dont support archiving more than 2G of objects");
273 _buffer->at_grow(to_array_index(min_bytes));
274 }
275
276 objArrayOop AOTMappedHeapWriter::allocate_root_segment(size_t offset, int element_count) {
277 HeapWord* mem = offset_to_buffered_address<HeapWord *>(offset);
278 memset(mem, 0, refArrayOopDesc::object_size(element_count));
279
280 // The initialization code is copied from MemAllocator::finish and ObjArrayAllocator::initialize.
281 if (UseCompactObjectHeaders) {
282 oopDesc::release_set_mark(mem, Universe::objectArrayKlass()->prototype_header());
283 } else {
284 assert(!Arguments::is_valhalla_enabled() || Universe::objectArrayKlass()->prototype_header() == markWord::prototype(), "should be the same");
285 oopDesc::set_mark(mem, markWord::prototype());
286 oopDesc::release_set_klass(mem, Universe::objectArrayKlass());
287 }
288 arrayOopDesc::set_length(mem, element_count);
289 return objArrayOop(cast_to_oop(mem));
290 }
291
292 void AOTMappedHeapWriter::root_segment_at_put(objArrayOop segment, int index, oop root) {
293 // Do not use arrayOop->obj_at_put(i, o) as arrayOop is outside the real heap!
294 if (UseCompressedOops) {
295 *segment->obj_at_addr<narrowOop>(index) = CompressedOops::encode(root);
296 } else {
297 *segment->obj_at_addr<oop>(index) = root;
298 }
299 }
300
301 void AOTMappedHeapWriter::copy_roots_to_buffer(GrowableArrayCHeap<oop, mtClassShared>* roots) {
302 // Depending on the number of classes we are archiving, a single roots array may be
303 // larger than MIN_GC_REGION_ALIGNMENT. Roots are allocated first in the buffer, which
304 // allows us to chop the large array into a series of "segments". Current layout
305 // starts with zero or more segments exactly fitting MIN_GC_REGION_ALIGNMENT, and end
306 // with a single segment that may be smaller than MIN_GC_REGION_ALIGNMENT.
307 // This is simple and efficient. We do not need filler objects anywhere between the segments,
308 // or immediately after the last segment. This allows starting the object dump immediately
309 // after the roots.
310
311 assert((_buffer_used % MIN_GC_REGION_ALIGNMENT) == 0,
312 "Pre-condition: Roots start at aligned boundary: %zu", _buffer_used);
313
314 int max_elem_count = ((MIN_GC_REGION_ALIGNMENT - arrayOopDesc::header_size_in_bytes()) / heapOopSize);
315 assert(refArrayOopDesc::object_size(max_elem_count)*HeapWordSize == MIN_GC_REGION_ALIGNMENT,
316 "Should match exactly");
317
318 HeapRootSegments segments(_buffer_used,
319 roots->length(),
320 MIN_GC_REGION_ALIGNMENT,
321 max_elem_count);
322
323 int root_index = 0;
324 for (size_t seg_idx = 0; seg_idx < segments.count(); seg_idx++) {
325 int size_elems = segments.size_in_elems(seg_idx);
326 size_t size_bytes = segments.size_in_bytes(seg_idx);
327
328 size_t oop_offset = _buffer_used;
329 _buffer_used = oop_offset + size_bytes;
330 ensure_buffer_space(_buffer_used);
331
332 assert((oop_offset % MIN_GC_REGION_ALIGNMENT) == 0,
333 "Roots segment %zu start is not aligned: %zu",
334 segments.count(), oop_offset);
335
336 objArrayOop seg_oop = allocate_root_segment(oop_offset, size_elems);
337 for (int i = 0; i < size_elems; i++) {
338 root_segment_at_put(seg_oop, i, roots->at(root_index++));
339 }
340
341 log_info(aot, heap)("archived obj root segment [%d] = %zu bytes, obj = " PTR_FORMAT,
342 size_elems, size_bytes, p2i(seg_oop));
343 }
344
345 assert(root_index == roots->length(), "Post-condition: All roots are handled");
346
347 _heap_root_segments = segments;
348 }
349
350 // The goal is to sort the objects in increasing order of:
351 // - objects that have only oop pointers
352 // - objects that have both native and oop pointers
353 // - objects that have only native pointers
354 // - objects that have no pointers
355 static int oop_sorting_rank(oop o) {
356 bool has_oop_ptr, has_native_ptr;
357 HeapShared::get_pointer_info(o, has_oop_ptr, has_native_ptr);
358
359 if (has_oop_ptr) {
360 if (!has_native_ptr) {
361 return 0;
362 } else {
363 return 1;
364 }
365 } else {
366 if (has_native_ptr) {
367 return 2;
368 } else {
369 return 3;
370 }
371 }
372 }
373
374 int AOTMappedHeapWriter::compare_objs_by_oop_fields(HeapObjOrder* a, HeapObjOrder* b) {
375 int rank_a = a->_rank;
376 int rank_b = b->_rank;
377
378 if (rank_a != rank_b) {
379 return rank_a - rank_b;
380 } else {
381 // If they are the same rank, sort them by their position in the _source_objs array
382 return a->_index - b->_index;
383 }
384 }
385
386 void AOTMappedHeapWriter::sort_source_objs() {
387 log_info(aot)("sorting heap objects");
388 int len = _source_objs->length();
389 _source_objs_order = new GrowableArrayCHeap<HeapObjOrder, mtClassShared>(len);
390
391 for (int i = 0; i < len; i++) {
392 oop o = _source_objs->at(i);
393 int rank = oop_sorting_rank(o);
394 HeapObjOrder os = {i, rank};
395 _source_objs_order->append(os);
396 }
397 log_info(aot)("computed ranks");
398 _source_objs_order->sort(compare_objs_by_oop_fields);
399 log_info(aot)("sorting heap objects done");
400 }
401
402 void AOTMappedHeapWriter::copy_source_objs_to_buffer(GrowableArrayCHeap<oop, mtClassShared>* roots) {
403 // There could be multiple root segments, which we want to be aligned by region.
404 // Putting them ahead of objects makes sure we waste no space.
405 copy_roots_to_buffer(roots);
406
407 sort_source_objs();
408 for (int i = 0; i < _source_objs_order->length(); i++) {
409 int src_obj_index = _source_objs_order->at(i)._index;
410 oop src_obj = _source_objs->at(src_obj_index);
411 HeapShared::CachedOopInfo* info = HeapShared::get_cached_oop_info(src_obj);
412 assert(info != nullptr, "must be");
413 size_t buffer_offset = copy_one_source_obj_to_buffer(src_obj);
414 info->set_buffer_offset(buffer_offset);
415 assert(buffer_offset <= 0x7fffffff, "sanity");
416
417 OopHandle handle(Universe::vm_global(), src_obj);
418 _buffer_offset_to_source_obj_table->put_when_absent(buffer_offset, handle);
419 _buffer_offset_to_source_obj_table->maybe_grow();
420
421 if (java_lang_Module::is_instance(src_obj)) {
422 Modules::check_archived_module_oop(src_obj);
423 }
424 }
425
426 log_info(aot)("Size of heap region = %zu bytes, %d objects, %d roots, %d native ptrs",
427 _buffer_used, _source_objs->length() + 1, roots->length(), _num_native_ptrs);
428 log_info(aot)(" strings = %8zu (%zu bytes)", _num_strings, _string_bytes);
429 log_info(aot)(" packages = %8zu", _num_packages);
430 log_info(aot)(" protection domains = %8zu", _num_protection_domains);
431 }
432
433 size_t AOTMappedHeapWriter::filler_array_byte_size(int length) {
434 size_t byte_size = refArrayOopDesc::object_size(length) * HeapWordSize;
435 return byte_size;
436 }
437
438 int AOTMappedHeapWriter::filler_array_length(size_t fill_bytes) {
439 assert(is_object_aligned(fill_bytes), "must be");
440 size_t elemSize = (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop));
441
442 int initial_length = to_array_length(fill_bytes / elemSize);
443 for (int length = initial_length; length >= 0; length --) {
444 size_t array_byte_size = filler_array_byte_size(length);
445 if (array_byte_size == fill_bytes) {
446 return length;
447 }
448 }
449
450 ShouldNotReachHere();
451 return -1;
452 }
453
454 HeapWord* AOTMappedHeapWriter::init_filler_array_at_buffer_top(int array_length, size_t fill_bytes) {
455 Klass* oak = Universe::objectArrayKlass(); // already relocated to point to archived klass
456 HeapWord* mem = offset_to_buffered_address<HeapWord*>(_buffer_used);
457 memset(mem, 0, fill_bytes);
458 narrowKlass nk = ArchiveBuilder::current()->get_requested_narrow_klass(oak);
459 if (UseCompactObjectHeaders) {
460 oopDesc::release_set_mark(mem, markWord::prototype().set_narrow_klass(nk));
461 } else {
462 assert(!Arguments::is_valhalla_enabled() || Universe::objectArrayKlass()->prototype_header() == markWord::prototype(), "should be the same");
463 oopDesc::set_mark(mem, markWord::prototype());
464 cast_to_oop(mem)->set_narrow_klass(nk);
465 }
466 arrayOopDesc::set_length(mem, array_length);
467 return mem;
468 }
469
470 void AOTMappedHeapWriter::maybe_fill_gc_region_gap(size_t required_byte_size) {
471 // We fill only with arrays (so we don't need to use a single HeapWord filler if the
472 // leftover space is smaller than a zero-sized array object). Therefore, we need to
473 // make sure there's enough space of min_filler_byte_size in the current region after
474 // required_byte_size has been allocated. If not, fill the remainder of the current
475 // region.
476 size_t min_filler_byte_size = filler_array_byte_size(0);
477 size_t new_used = _buffer_used + required_byte_size + min_filler_byte_size;
478
479 const size_t cur_min_region_bottom = align_down(_buffer_used, MIN_GC_REGION_ALIGNMENT);
480 const size_t next_min_region_bottom = align_down(new_used, MIN_GC_REGION_ALIGNMENT);
481
482 if (cur_min_region_bottom != next_min_region_bottom) {
483 // Make sure that no objects span across MIN_GC_REGION_ALIGNMENT. This way
484 // we can map the region in any region-based collector.
485 assert(next_min_region_bottom > cur_min_region_bottom, "must be");
486 assert(next_min_region_bottom - cur_min_region_bottom == MIN_GC_REGION_ALIGNMENT,
487 "no buffered object can be larger than %d bytes", MIN_GC_REGION_ALIGNMENT);
488
489 const size_t filler_end = next_min_region_bottom;
490 const size_t fill_bytes = filler_end - _buffer_used;
491 assert(fill_bytes > 0, "must be");
492 ensure_buffer_space(filler_end);
493
494 int array_length = filler_array_length(fill_bytes);
495 log_info(aot, heap)("Inserting filler obj array of %d elements (%zu bytes total) @ buffer offset %zu",
496 array_length, fill_bytes, _buffer_used);
497 HeapWord* filler = init_filler_array_at_buffer_top(array_length, fill_bytes);
498 _buffer_used = filler_end;
499 _fillers->put(buffered_address_to_offset((address)filler), fill_bytes);
500 }
501 }
502
503 size_t AOTMappedHeapWriter::get_filler_size_at(address buffered_addr) {
504 size_t* p = _fillers->get(buffered_address_to_offset(buffered_addr));
505 if (p != nullptr) {
506 assert(*p > 0, "filler must be larger than zero bytes");
507 return *p;
508 } else {
509 return 0; // buffered_addr is not a filler
510 }
511 }
512
513 template <typename T>
514 void update_buffered_object_field(address buffered_obj, int field_offset, T value) {
515 T* field_addr = cast_to_oop(buffered_obj)->field_addr<T>(field_offset);
516 *field_addr = value;
517 }
518
519 void AOTMappedHeapWriter::update_stats(oop src_obj) {
520 if (java_lang_String::is_instance(src_obj)) {
521 _num_strings ++;
522 _string_bytes += src_obj->size() * HeapWordSize;
523 _string_bytes += java_lang_String::value(src_obj)->size() * HeapWordSize;
524 } else {
525 Klass* k = src_obj->klass();
526 Symbol* name = k->name();
527 if (name->equals("java/lang/NamedPackage") || name->equals("java/lang/Package")) {
528 _num_packages ++;
529 } else if (name->equals("java/security/ProtectionDomain")) {
530 _num_protection_domains ++;
531 }
532 }
533 }
534
535 size_t AOTMappedHeapWriter::copy_one_source_obj_to_buffer(oop src_obj) {
536 update_stats(src_obj);
537
538 assert(!is_too_large_to_archive(src_obj), "already checked");
539 size_t byte_size = src_obj->size() * HeapWordSize;
540 assert(byte_size > 0, "no zero-size objects");
541
542 // For region-based collectors such as G1, the archive heap may be mapped into
543 // multiple regions. We need to make sure that we don't have an object that can possible
544 // span across two regions.
545 maybe_fill_gc_region_gap(byte_size);
546
547 size_t new_used = _buffer_used + byte_size;
548 assert(new_used > _buffer_used, "no wrap around");
549
550 size_t cur_min_region_bottom = align_down(_buffer_used, MIN_GC_REGION_ALIGNMENT);
551 size_t next_min_region_bottom = align_down(new_used, MIN_GC_REGION_ALIGNMENT);
552 assert(cur_min_region_bottom == next_min_region_bottom, "no object should cross minimal GC region boundaries");
553
554 ensure_buffer_space(new_used);
555
556 address from = cast_from_oop<address>(src_obj);
557 address to = offset_to_buffered_address<address>(_buffer_used);
558 assert(is_object_aligned(_buffer_used), "sanity");
559 assert(is_object_aligned(byte_size), "sanity");
560 memcpy(to, from, byte_size);
561
562 // These native pointers will be restored explicitly at run time.
563 if (java_lang_Module::is_instance(src_obj)) {
564 update_buffered_object_field<ModuleEntry*>(to, java_lang_Module::module_entry_offset(), nullptr);
565 } else if (java_lang_ClassLoader::is_instance(src_obj)) {
566 #ifdef ASSERT
567 // We only archive these loaders
568 if (src_obj != SystemDictionary::java_platform_loader() &&
569 src_obj != SystemDictionary::java_system_loader()) {
570 assert(src_obj->klass()->name()->equals("jdk/internal/loader/ClassLoaders$BootClassLoader"), "must be");
571 }
572 #endif
573 update_buffered_object_field<ClassLoaderData*>(to, java_lang_ClassLoader::loader_data_offset(), nullptr);
574 }
575
576 size_t buffered_obj_offset = _buffer_used;
577 _buffer_used = new_used;
578
579 return buffered_obj_offset;
580 }
581
582 // Set the range [_requested_bottom, _requested_top), the requested address range of all
583 // the archived heap objects in the production run.
584 //
585 // (1) UseCompressedOops == true && !is_writing_deterministic_heap()
586 //
587 // The archived objects are stored using the COOPS encoding of the assembly phase.
588 // We pick a range within the heap used by the assembly phase.
589 //
590 // In the production run, if different COOPS encodings are used:
591 // - The heap contents needs to be relocated.
592 //
593 // (2) UseCompressedOops == true && is_writing_deterministic_heap()
594 //
595 // We always use zero-based, zero-shift encoding. _requested_top is aligned to 0x10000000.
596 //
597 // (3) UseCompressedOops == false:
598 //
599 // In the production run, the heap range is usually picked (randomly) by the OS, so we
600 // will almost always need to perform relocation, regardless of how we pick the requested
601 // address range.
602 //
603 // So we just hard code it to NOCOOPS_REQUESTED_BASE.
604 //
605 void AOTMappedHeapWriter::set_requested_address_range(AOTMappedHeapInfo* info) {
606 assert(!info->is_used(), "only set once");
607
608 size_t heap_region_byte_size = _buffer_used;
609 assert(heap_region_byte_size > 0, "must archived at least one object!");
610
611 if (UseCompressedOops) {
612 if (is_writing_deterministic_heap()) {
613 // Pick a heap range so that requested addresses can be encoded with zero-base/no shift.
614 // We align the requested bottom to at least 1 MB: if the production run uses G1 with a small
615 // heap (e.g., -Xmx256m), it's likely that we can map the archived objects at the
616 // requested location to avoid relocation.
617 //
618 // For other collectors or larger heaps, relocation is unavoidable, but is usually
619 // quite cheap. If you really want to avoid relocation, use the AOT workflow instead.
620 address heap_end = (address)0x100000000;
621 size_t alignment = MAX2(MIN_GC_REGION_ALIGNMENT, 1024 * 1024);
622 if (align_up(heap_region_byte_size, alignment) >= (size_t)heap_end) {
623 log_error(aot, heap)("cached heap space is too large: %zu bytes", heap_region_byte_size);
624 AOTMetaspace::unrecoverable_writing_error();
625 }
626 _requested_bottom = align_down(heap_end - heap_region_byte_size, alignment);
627 } else if (UseG1GC) {
628 // For G1, pick the range at the top of the current heap. If the exact same heap sizes
629 // are used in the production run, it's likely that we can map the archived objects
630 // at the requested location to avoid relocation.
631 address heap_end = (address)G1CollectedHeap::heap()->reserved().end();
632 log_info(aot, heap)("Heap end = %p", heap_end);
633 _requested_bottom = align_down(heap_end - heap_region_byte_size, G1HeapRegion::GrainBytes);
634 _requested_bottom = align_down(_requested_bottom, MIN_GC_REGION_ALIGNMENT);
635 assert(is_aligned(_requested_bottom, G1HeapRegion::GrainBytes), "sanity");
636 } else {
637 _requested_bottom = align_up(CompressedOops::begin(), MIN_GC_REGION_ALIGNMENT);
638 }
639 } else {
640 // We always write the objects as if the heap started at this address. This
641 // makes the contents of the archive heap deterministic.
642 //
643 // Note that at runtime, the heap address is selected by the OS, so the archive
644 // heap will not be mapped at 0x10000000, and the contents need to be patched.
645 _requested_bottom = align_up((address)NOCOOPS_REQUESTED_BASE, MIN_GC_REGION_ALIGNMENT);
646 }
647
648 assert(is_aligned(_requested_bottom, MIN_GC_REGION_ALIGNMENT), "sanity");
649
650 _requested_top = _requested_bottom + _buffer_used;
651
652 info->set_buffer_region(MemRegion(offset_to_buffered_address<HeapWord*>(0),
653 offset_to_buffered_address<HeapWord*>(_buffer_used)));
654 info->set_root_segments(_heap_root_segments);
655 }
656
657 // Oop relocation
658
659 template <typename T> T* AOTMappedHeapWriter::requested_addr_to_buffered_addr(T* p) {
660 assert(is_in_requested_range(cast_to_oop(p)), "must be");
661
662 address addr = address(p);
663 assert(addr >= _requested_bottom, "must be");
664 size_t offset = addr - _requested_bottom;
665 return offset_to_buffered_address<T*>(offset);
666 }
667
668 template <typename T> oop AOTMappedHeapWriter::load_source_oop_from_buffer(T* buffered_addr) {
669 oop o = load_oop_from_buffer(buffered_addr);
670 assert(!in_buffer(cast_from_oop<address>(o)), "must point to source oop");
671 return o;
672 }
673
674 template <typename T> void AOTMappedHeapWriter::store_requested_oop_in_buffer(T* buffered_addr,
675 oop request_oop) {
676 assert(request_oop == nullptr || is_in_requested_range(request_oop), "must be");
677 store_oop_in_buffer(buffered_addr, request_oop);
678 }
679
680 inline void AOTMappedHeapWriter::store_oop_in_buffer(oop* buffered_addr, oop requested_obj) {
681 *buffered_addr = requested_obj;
682 }
683
684 inline void AOTMappedHeapWriter::store_oop_in_buffer(narrowOop* buffered_addr, oop requested_obj) {
685 narrowOop val = CompressedOops::encode(requested_obj);
686 *buffered_addr = val;
687 }
688
689 oop AOTMappedHeapWriter::load_oop_from_buffer(oop* buffered_addr) {
690 return *buffered_addr;
691 }
692
693 oop AOTMappedHeapWriter::load_oop_from_buffer(narrowOop* buffered_addr) {
694 return CompressedOops::decode(*buffered_addr);
695 }
696
697 template <typename T> void AOTMappedHeapWriter::relocate_field_in_buffer(T* field_addr_in_buffer, oop source_referent, CHeapBitMap* oopmap) {
698 oop request_referent = source_obj_to_requested_obj(source_referent);
699 if (UseCompressedOops && is_writing_deterministic_heap()) {
700 // We use zero-based, 0-shift encoding, so the narrowOop is just the lower
701 // 32 bits of request_referent
702 intptr_t addr = cast_from_oop<intptr_t>(request_referent);
703 *((narrowOop*)field_addr_in_buffer) = CompressedOops::narrow_oop_cast(addr);
704 } else {
705 store_requested_oop_in_buffer<T>(field_addr_in_buffer, request_referent);
706 }
707 if (request_referent != nullptr) {
708 mark_oop_pointer<T>(field_addr_in_buffer, oopmap);
709 }
710 }
711
712 template <typename T> void AOTMappedHeapWriter::mark_oop_pointer(T* buffered_addr, CHeapBitMap* oopmap) {
713 T* request_p = (T*)(buffered_addr_to_requested_addr((address)buffered_addr));
714 address requested_region_bottom;
715
716 assert(request_p >= (T*)_requested_bottom, "sanity");
717 assert(request_p < (T*)_requested_top, "sanity");
718 requested_region_bottom = _requested_bottom;
719
720 // Mark the pointer in the oopmap
721 T* region_bottom = (T*)requested_region_bottom;
722 assert(request_p >= region_bottom, "must be");
723 BitMap::idx_t idx = request_p - region_bottom;
724 assert(idx < oopmap->size(), "overflow");
725 oopmap->set_bit(idx);
726 }
727
728 void AOTMappedHeapWriter::update_header_for_requested_obj(oop requested_obj, oop src_obj, Klass* src_klass) {
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 if (!ArchiveBuilder::current()->has_been_archived((address)native_ptr)) {
906 ResourceMark rm;
907 LogStreamHandle(Error, aot) log;
908 log.print("Marking native pointer for oop %p (type = %s, offset = %d)",
909 cast_from_oop<void*>(src_obj), src_obj->klass()->external_name(), field_offset);
910 src_obj->print_on(&log);
911 fatal("Metadata %p should have been archived", native_ptr);
912 }
913
914 address buffered_native_ptr = ArchiveBuilder::current()->get_buffered_addr((address)native_ptr);
915 address requested_native_ptr = ArchiveBuilder::current()->to_requested(buffered_native_ptr);
916 *buffered_field_addr = (Metadata*)requested_native_ptr;
917 }
918
919 heap_info->ptrmap()->resize(max_idx + 1);
920 log_info(aot, heap)("calculate_ptrmap: marked %d non-null native pointers for heap region (%zu bits)",
921 num_non_null_ptrs, size_t(heap_info->ptrmap()->size()));
922 }
923
924 AOTMapLogger::OopDataIterator* AOTMappedHeapWriter::oop_iterator(AOTMappedHeapInfo* heap_info) {
925 class MappedWriterOopIterator : public AOTMappedHeapOopIterator {
926 public:
927 MappedWriterOopIterator(address buffer_start,
928 address buffer_end,
929 address requested_base,
930 address requested_start,
931 int requested_shift,
932 size_t num_root_segments) :
933 AOTMappedHeapOopIterator(buffer_start,
934 buffer_end,
935 requested_base,
936 requested_start,
937 requested_shift,
938 num_root_segments) {}
939
940 AOTMapLogger::OopData capture(address buffered_addr) override {
941 oopDesc* raw_oop = (oopDesc*)buffered_addr;
942 size_t size = size_of_buffered_oop(buffered_addr);
943 address requested_addr = buffered_addr_to_requested_addr(buffered_addr);
944 intptr_t target_location = (intptr_t)requested_addr;
945 uint64_t pd = (uint64_t)(pointer_delta(buffered_addr, _buffer_start, 1));
946 uint32_t narrow_location = checked_cast<uint32_t>(_buffer_start_narrow_oop + (pd >> _requested_shift));
947 Klass* klass = real_klass_of_buffered_oop(buffered_addr);
948
949 return { buffered_addr,
950 requested_addr,
951 target_location,
952 narrow_location,
953 raw_oop,
954 klass,
955 size,
956 false };
957 }
958 };
959
960 MemRegion r = heap_info->buffer_region();
961 address buffer_start = address(r.start());
962 address buffer_end = address(r.end());
963
964 address requested_base = UseCompressedOops ? AOTMappedHeapWriter::narrow_oop_base() : (address)AOTMappedHeapWriter::NOCOOPS_REQUESTED_BASE;
965 address requested_start = UseCompressedOops ? AOTMappedHeapWriter::buffered_addr_to_requested_addr(buffer_start) : requested_base;
966 int requested_shift = AOTMappedHeapWriter::narrow_oop_shift();
967
968 return new MappedWriterOopIterator(buffer_start,
969 buffer_end,
970 requested_base,
971 requested_start,
972 requested_shift,
973 heap_info->root_segments().count());
974 }
975
976 #endif // INCLUDE_CDS_JAVA_HEAP