1 /*
2 * Copyright (c) 2023, 2025, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "cds/aotMappedHeapLoader.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 GrowableArrayCHeap<AOTMappedHeapWriter::NativePointerInfo, mtClassShared>* AOTMappedHeapWriter::_native_pointers;
68 GrowableArrayCHeap<oop, mtClassShared>* AOTMappedHeapWriter::_source_objs;
69 GrowableArrayCHeap<AOTMappedHeapWriter::HeapObjOrder, mtClassShared>* AOTMappedHeapWriter::_source_objs_order;
70
71 AOTMappedHeapWriter::BufferOffsetToSourceObjectTable*
72 AOTMappedHeapWriter::_buffer_offset_to_source_obj_table = nullptr;
73
74 DumpedInternedStrings *AOTMappedHeapWriter::_dumped_interned_strings = nullptr;
75
76 typedef HashTable<
77 size_t, // offset of a filler from AOTMappedHeapWriter::buffer_bottom()
78 size_t, // size of this filler (in bytes)
79 127, // prime number
80 AnyObj::C_HEAP,
81 mtClassShared> FillersTable;
82 static FillersTable* _fillers;
83 static int _num_native_ptrs = 0;
84
85 void AOTMappedHeapWriter::init() {
86 if (CDSConfig::is_dumping_heap()) {
87 Universe::heap()->collect(GCCause::_java_lang_system_gc);
88
89 _buffer_offset_to_source_obj_table = new BufferOffsetToSourceObjectTable(/*size (prime)*/36137, /*max size*/1 * M);
90 _dumped_interned_strings = new (mtClass)DumpedInternedStrings(INITIAL_TABLE_SIZE, MAX_TABLE_SIZE);
91 _fillers = new FillersTable();
92 _requested_bottom = nullptr;
93 _requested_top = nullptr;
94
95 _native_pointers = new GrowableArrayCHeap<NativePointerInfo, mtClassShared>(2048);
96 _source_objs = new GrowableArrayCHeap<oop, mtClassShared>(10000);
97
98 guarantee(MIN_GC_REGION_ALIGNMENT <= G1HeapRegion::min_region_size_in_words() * HeapWordSize, "must be");
99
100 if (CDSConfig::old_cds_flags_used()) {
101 // With the old CDS workflow, we can guatantee determninistic output: given
102 // the same classlist file, we can generate the same static CDS archive.
103 // To ensure determinism, we always use the same compressed oop encoding
104 // (zero-based, no shift). See set_requested_address_range().
105 _is_writing_deterministic_heap = true;
106 } else {
107 // Determninistic output is not supported by the new AOT workflow, so
108 // we don't force the (zero-based, no shift) encoding. This way, it is more
109 // likely that we can avoid oop relocation in the production run.
110 _is_writing_deterministic_heap = false;
111 }
112 }
113 }
114
115 // For AOTMappedHeapWriter::narrow_oop_{mode, base, shift}(), see comments
116 // in AOTMappedHeapWriter::set_requested_address_range(),
117 CompressedOops::Mode AOTMappedHeapWriter::narrow_oop_mode() {
118 if (is_writing_deterministic_heap()) {
119 return CompressedOops::UnscaledNarrowOop;
120 } else {
121 return CompressedOops::mode();
122 }
123 }
124
125 address AOTMappedHeapWriter::narrow_oop_base() {
126 if (is_writing_deterministic_heap()) {
127 return (address)0;
128 } else {
129 return CompressedOops::base();
130 }
131 }
132
133 int AOTMappedHeapWriter::narrow_oop_shift() {
134 if (is_writing_deterministic_heap()) {
135 return 0;
136 } else {
137 return CompressedOops::shift();
138 }
139 }
140
141 void AOTMappedHeapWriter::delete_tables_with_raw_oops() {
142 delete _source_objs;
143 _source_objs = nullptr;
144
145 delete _dumped_interned_strings;
146 _dumped_interned_strings = 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 ArchiveMappedHeapInfo* 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 size_t size = o->size();
164 size = o->copy_size_cds(size, o->mark());
165 return is_too_large_to_archive(size);
166 }
167
168 bool AOTMappedHeapWriter::is_string_too_large_to_archive(oop string) {
169 typeArrayOop value = java_lang_String::value_no_keepalive(string);
170 return is_too_large_to_archive(value);
171 }
172
173 bool AOTMappedHeapWriter::is_too_large_to_archive(size_t size) {
174 assert(size > 0, "no zero-size object");
175 assert(size * HeapWordSize > size, "no overflow");
176 static_assert(MIN_GC_REGION_ALIGNMENT > 0, "must be positive");
177
178 size_t byte_size = size * HeapWordSize;
179 if (byte_size > size_t(MIN_GC_REGION_ALIGNMENT)) {
180 return true;
181 } else {
182 return false;
183 }
184 }
185
186 // Keep track of the contents of the archived interned string table. This table
187 // is used only by CDSHeapVerifier.
188 void AOTMappedHeapWriter::add_to_dumped_interned_strings(oop string) {
189 assert_at_safepoint(); // DumpedInternedStrings uses raw oops
190 assert(!is_string_too_large_to_archive(string), "must be");
191 bool created;
192 _dumped_interned_strings->put_if_absent(string, true, &created);
193 if (created) {
194 // Prevent string deduplication from changing the value field to
195 // something not in the archive.
196 java_lang_String::set_deduplication_forbidden(string);
197 _dumped_interned_strings->maybe_grow();
198 }
199 }
200
201 bool AOTMappedHeapWriter::is_dumped_interned_string(oop o) {
202 return _dumped_interned_strings->get(o) != nullptr;
203 }
204
205 // Various lookup functions between source_obj, buffered_obj and requested_obj
206 bool AOTMappedHeapWriter::is_in_requested_range(oop o) {
207 assert(_requested_bottom != nullptr, "do not call before _requested_bottom is initialized");
208 address a = cast_from_oop<address>(o);
209 return (_requested_bottom <= a && a < _requested_top);
210 }
211
212 oop AOTMappedHeapWriter::requested_obj_from_buffer_offset(size_t offset) {
213 oop req_obj = cast_to_oop(_requested_bottom + offset);
214 assert(is_in_requested_range(req_obj), "must be");
215 return req_obj;
216 }
217
218 oop AOTMappedHeapWriter::source_obj_to_requested_obj(oop src_obj) {
219 assert(CDSConfig::is_dumping_heap(), "dump-time only");
220 HeapShared::CachedOopInfo* p = HeapShared::get_cached_oop_info(src_obj);
221 if (p != nullptr) {
222 return requested_obj_from_buffer_offset(p->buffer_offset());
223 } else {
224 return nullptr;
225 }
226 }
227
228 oop AOTMappedHeapWriter::buffered_addr_to_source_obj(address buffered_addr) {
229 OopHandle* oh = _buffer_offset_to_source_obj_table->get(buffered_address_to_offset(buffered_addr));
230 if (oh != nullptr) {
231 return oh->resolve();
232 } else {
233 return nullptr;
234 }
235 }
236
237 Klass* AOTMappedHeapWriter::real_klass_of_buffered_oop(address buffered_addr) {
238 oop p = buffered_addr_to_source_obj(buffered_addr);
239 if (p != nullptr) {
240 return p->klass();
241 } else if (get_filler_size_at(buffered_addr) > 0) {
242 return Universe::fillerArrayKlass();
243 } else {
244 // This is one of the root segments
245 return Universe::objectArrayKlass();
246 }
247 }
248
249 size_t AOTMappedHeapWriter::size_of_buffered_oop(address buffered_addr) {
250 oop p = buffered_addr_to_source_obj(buffered_addr);
251 if (p != nullptr) {
252 size_t size = p->size();
253 return p->copy_size_cds(size, p->mark());
254 }
255
256 size_t nbytes = get_filler_size_at(buffered_addr);
257 if (nbytes > 0) {
258 assert((nbytes % BytesPerWord) == 0, "should be aligned");
259 return nbytes / BytesPerWord;
260 }
261
262 address hrs = buffer_bottom();
263 for (size_t seg_idx = 0; seg_idx < _heap_root_segments.count(); seg_idx++) {
264 nbytes = _heap_root_segments.size_in_bytes(seg_idx);
265 if (hrs == buffered_addr) {
266 assert((nbytes % BytesPerWord) == 0, "should be aligned");
267 return nbytes / BytesPerWord;
268 }
269 hrs += nbytes;
270 }
271
272 ShouldNotReachHere();
273 return 0;
274 }
275
276 address AOTMappedHeapWriter::buffered_addr_to_requested_addr(address buffered_addr) {
277 return _requested_bottom + buffered_address_to_offset(buffered_addr);
278 }
279
280 address AOTMappedHeapWriter::requested_address() {
281 assert(_buffer != nullptr, "must be initialized");
282 return _requested_bottom;
283 }
284
285 void AOTMappedHeapWriter::allocate_buffer() {
286 int initial_buffer_size = 100000;
287 _buffer = new GrowableArrayCHeap<u1, mtClassShared>(initial_buffer_size);
288 _buffer_used = 0;
289 ensure_buffer_space(1); // so that buffer_bottom() works
290 }
291
292 void AOTMappedHeapWriter::ensure_buffer_space(size_t min_bytes) {
293 // We usually have very small heaps. If we get a huge one it's probably caused by a bug.
294 guarantee(min_bytes <= max_jint, "we dont support archiving more than 2G of objects");
295 _buffer->at_grow(to_array_index(min_bytes));
296 }
297
298 objArrayOop AOTMappedHeapWriter::allocate_root_segment(size_t offset, int element_count) {
299 HeapWord* mem = offset_to_buffered_address<HeapWord *>(offset);
300 memset(mem, 0, objArrayOopDesc::object_size(element_count));
301
302 // The initialization code is copied from MemAllocator::finish and ObjArrayAllocator::initialize.
303 if (UseCompactObjectHeaders) {
304 oopDesc::release_set_mark(mem, Universe::objectArrayKlass()->prototype_header());
305 } else {
306 oopDesc::set_mark(mem, markWord::prototype());
307 oopDesc::release_set_klass(mem, Universe::objectArrayKlass());
308 }
309 arrayOopDesc::set_length(mem, element_count);
310 return objArrayOop(cast_to_oop(mem));
311 }
312
313 void AOTMappedHeapWriter::root_segment_at_put(objArrayOop segment, int index, oop root) {
314 // Do not use arrayOop->obj_at_put(i, o) as arrayOop is outside the real heap!
315 if (UseCompressedOops) {
316 *segment->obj_at_addr<narrowOop>(index) = CompressedOops::encode(root);
317 } else {
318 *segment->obj_at_addr<oop>(index) = root;
319 }
320 }
321
322 void AOTMappedHeapWriter::copy_roots_to_buffer(GrowableArrayCHeap<oop, mtClassShared>* roots) {
323 // Depending on the number of classes we are archiving, a single roots array may be
324 // larger than MIN_GC_REGION_ALIGNMENT. Roots are allocated first in the buffer, which
325 // allows us to chop the large array into a series of "segments". Current layout
326 // starts with zero or more segments exactly fitting MIN_GC_REGION_ALIGNMENT, and end
327 // with a single segment that may be smaller than MIN_GC_REGION_ALIGNMENT.
328 // This is simple and efficient. We do not need filler objects anywhere between the segments,
329 // or immediately after the last segment. This allows starting the object dump immediately
330 // after the roots.
331
332 assert((_buffer_used % MIN_GC_REGION_ALIGNMENT) == 0,
333 "Pre-condition: Roots start at aligned boundary: %zu", _buffer_used);
334
335 int max_elem_count = ((MIN_GC_REGION_ALIGNMENT - arrayOopDesc::header_size_in_bytes()) / heapOopSize);
336 assert(objArrayOopDesc::object_size(max_elem_count)*HeapWordSize == MIN_GC_REGION_ALIGNMENT,
337 "Should match exactly");
338
339 HeapRootSegments segments(_buffer_used,
340 roots->length(),
341 MIN_GC_REGION_ALIGNMENT,
342 max_elem_count);
343
344 int root_index = 0;
345 for (size_t seg_idx = 0; seg_idx < segments.count(); seg_idx++) {
346 int size_elems = segments.size_in_elems(seg_idx);
347 size_t size_bytes = segments.size_in_bytes(seg_idx);
348
349 size_t oop_offset = _buffer_used;
350 _buffer_used = oop_offset + size_bytes;
351 ensure_buffer_space(_buffer_used);
352
353 assert((oop_offset % MIN_GC_REGION_ALIGNMENT) == 0,
354 "Roots segment %zu start is not aligned: %zu",
355 segments.count(), oop_offset);
356
357 objArrayOop seg_oop = allocate_root_segment(oop_offset, size_elems);
358 for (int i = 0; i < size_elems; i++) {
359 root_segment_at_put(seg_oop, i, roots->at(root_index++));
360 }
361
362 log_info(aot, heap)("archived obj root segment [%d] = %zu bytes, obj = " PTR_FORMAT,
363 size_elems, size_bytes, p2i(seg_oop));
364 }
365
366 assert(root_index == roots->length(), "Post-condition: All roots are handled");
367
368 _heap_root_segments = segments;
369 }
370
371 // The goal is to sort the objects in increasing order of:
372 // - objects that have only oop pointers
373 // - objects that have both native and oop pointers
374 // - objects that have only native pointers
375 // - objects that have no pointers
376 static int oop_sorting_rank(oop o) {
377 bool has_oop_ptr, has_native_ptr;
378 HeapShared::get_pointer_info(o, has_oop_ptr, has_native_ptr);
379
380 if (has_oop_ptr) {
381 if (!has_native_ptr) {
382 return 0;
383 } else {
384 return 1;
385 }
386 } else {
387 if (has_native_ptr) {
388 return 2;
389 } else {
390 return 3;
391 }
392 }
393 }
394
395 int AOTMappedHeapWriter::compare_objs_by_oop_fields(HeapObjOrder* a, HeapObjOrder* b) {
396 int rank_a = a->_rank;
397 int rank_b = b->_rank;
398
399 if (rank_a != rank_b) {
400 return rank_a - rank_b;
401 } else {
402 // If they are the same rank, sort them by their position in the _source_objs array
403 return a->_index - b->_index;
404 }
405 }
406
407 void AOTMappedHeapWriter::sort_source_objs() {
408 log_info(aot)("sorting heap objects");
409 int len = _source_objs->length();
410 _source_objs_order = new GrowableArrayCHeap<HeapObjOrder, mtClassShared>(len);
411
412 for (int i = 0; i < len; i++) {
413 oop o = _source_objs->at(i);
414 int rank = oop_sorting_rank(o);
415 HeapObjOrder os = {i, rank};
416 _source_objs_order->append(os);
417 }
418 log_info(aot)("computed ranks");
419 _source_objs_order->sort(compare_objs_by_oop_fields);
420 log_info(aot)("sorting heap objects done");
421 }
422
423 void AOTMappedHeapWriter::copy_source_objs_to_buffer(GrowableArrayCHeap<oop, mtClassShared>* roots) {
424 // There could be multiple root segments, which we want to be aligned by region.
425 // Putting them ahead of objects makes sure we waste no space.
426 copy_roots_to_buffer(roots);
427
428 sort_source_objs();
429 for (int i = 0; i < _source_objs_order->length(); i++) {
430 int src_obj_index = _source_objs_order->at(i)._index;
431 oop src_obj = _source_objs->at(src_obj_index);
432 HeapShared::CachedOopInfo* info = HeapShared::get_cached_oop_info(src_obj);
433 assert(info != nullptr, "must be");
434 size_t buffer_offset = copy_one_source_obj_to_buffer(src_obj);
435 info->set_buffer_offset(buffer_offset);
436
437 OopHandle handle(Universe::vm_global(), src_obj);
438 _buffer_offset_to_source_obj_table->put_when_absent(buffer_offset, handle);
439 _buffer_offset_to_source_obj_table->maybe_grow();
440
441 if (java_lang_Module::is_instance(src_obj)) {
442 Modules::check_archived_module_oop(src_obj);
443 }
444 }
445
446 log_info(aot)("Size of heap region = %zu bytes, %d objects, %d roots, %d native ptrs",
447 _buffer_used, _source_objs->length() + 1, roots->length(), _num_native_ptrs);
448 }
449
450 size_t AOTMappedHeapWriter::filler_array_byte_size(int length) {
451 size_t byte_size = objArrayOopDesc::object_size(length) * HeapWordSize;
452 return byte_size;
453 }
454
455 int AOTMappedHeapWriter::filler_array_length(size_t fill_bytes) {
456 assert(is_object_aligned(fill_bytes), "must be");
457 size_t elemSize = (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop));
458
459 int initial_length = to_array_length(fill_bytes / elemSize);
460 for (int length = initial_length; length >= 0; length --) {
461 size_t array_byte_size = filler_array_byte_size(length);
462 if (array_byte_size == fill_bytes) {
463 return length;
464 }
465 }
466
467 ShouldNotReachHere();
468 return -1;
469 }
470
471 HeapWord* AOTMappedHeapWriter::init_filler_array_at_buffer_top(int array_length, size_t fill_bytes) {
472 assert(UseCompressedClassPointers, "Archived heap only supported for compressed klasses");
473 Klass* oak = Universe::objectArrayKlass(); // already relocated to point to archived klass
474 HeapWord* mem = offset_to_buffered_address<HeapWord*>(_buffer_used);
475 memset(mem, 0, fill_bytes);
476 narrowKlass nk = ArchiveBuilder::current()->get_requested_narrow_klass(oak);
477 if (UseCompactObjectHeaders) {
478 oopDesc::release_set_mark(mem, markWord::prototype().set_narrow_klass(nk));
479 } else {
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 old_size = src_obj->size();
539 size_t new_size = src_obj->copy_size_cds(old_size, src_obj->mark());
540 size_t byte_size = new_size * HeapWordSize;
541 assert(byte_size > 0, "no zero-size objects");
542
543 // For region-based collectors such as G1, the archive heap may be mapped into
544 // multiple regions. We need to make sure that we don't have an object that can possible
545 // span across two regions.
546 maybe_fill_gc_region_gap(byte_size);
547
548 size_t new_used = _buffer_used + byte_size;
549 assert(new_used > _buffer_used, "no wrap around");
550
551 size_t cur_min_region_bottom = align_down(_buffer_used, MIN_GC_REGION_ALIGNMENT);
552 size_t next_min_region_bottom = align_down(new_used, MIN_GC_REGION_ALIGNMENT);
553 assert(cur_min_region_bottom == next_min_region_bottom, "no object should cross minimal GC region boundaries");
554
555 ensure_buffer_space(new_used);
556
557 address from = cast_from_oop<address>(src_obj);
558 address to = offset_to_buffered_address<address>(_buffer_used);
559 assert(is_object_aligned(_buffer_used), "sanity");
560 assert(is_object_aligned(byte_size), "sanity");
561 memcpy(to, from, MIN2(new_size, old_size) * HeapWordSize);
562
563 // These native pointers will be restored explicitly at run time.
564 if (java_lang_Module::is_instance(src_obj)) {
565 update_buffered_object_field<ModuleEntry*>(to, java_lang_Module::module_entry_offset(), nullptr);
566 } else if (java_lang_ClassLoader::is_instance(src_obj)) {
567 #ifdef ASSERT
568 // We only archive these loaders
569 if (src_obj != SystemDictionary::java_platform_loader() &&
570 src_obj != SystemDictionary::java_system_loader()) {
571 assert(src_obj->klass()->name()->equals("jdk/internal/loader/ClassLoaders$BootClassLoader"), "must be");
572 }
573 #endif
574 update_buffered_object_field<ClassLoaderData*>(to, java_lang_ClassLoader::loader_data_offset(), nullptr);
575 }
576
577 size_t buffered_obj_offset = _buffer_used;
578 _buffer_used = new_used;
579
580 return buffered_obj_offset;
581 }
582
583 // Set the range [_requested_bottom, _requested_top), the requested address range of all
584 // the archived heap objects in the production run.
585 //
586 // (1) UseCompressedOops == true && !is_writing_deterministic_heap()
587 //
588 // The archived objects are stored using the COOPS encoding of the assembly phase.
589 // We pick a range within the heap used by the assembly phase.
590 //
591 // In the production run, if different COOPS encodings are used:
592 // - The heap contents needs to be relocated.
593 //
594 // (2) UseCompressedOops == true && is_writing_deterministic_heap()
595 //
596 // We always use zero-based, zero-shift encoding. _requested_top is aligned to 0x10000000.
597 //
598 // (3) UseCompressedOops == false:
599 //
600 // In the production run, the heap range is usually picked (randomly) by the OS, so we
601 // will almost always need to perform relocation, regardless of how we pick the requested
602 // address range.
603 //
604 // So we just hard code it to NOCOOPS_REQUESTED_BASE.
605 //
606 void AOTMappedHeapWriter::set_requested_address_range(ArchiveMappedHeapInfo* info) {
607 assert(!info->is_used(), "only set once");
608
609 size_t heap_region_byte_size = _buffer_used;
610 assert(heap_region_byte_size > 0, "must archived at least one object!");
611
612 if (UseCompressedOops) {
613 if (is_writing_deterministic_heap()) {
614 // Pick a heap range so that requested addresses can be encoded with zero-base/no shift.
615 // We align the requested bottom to at least 1 MB: if the production run uses G1 with a small
616 // heap (e.g., -Xmx256m), it's likely that we can map the archived objects at the
617 // requested location to avoid relocation.
618 //
619 // For other collectors or larger heaps, relocation is unavoidable, but is usually
620 // quite cheap. If you really want to avoid relocation, use the AOT workflow instead.
621 address heap_end = (address)0x100000000;
622 size_t alignment = MAX2(MIN_GC_REGION_ALIGNMENT, 1024 * 1024);
623 if (align_up(heap_region_byte_size, alignment) >= (size_t)heap_end) {
624 log_error(aot, heap)("cached heap space is too large: %zu bytes", heap_region_byte_size);
625 AOTMetaspace::unrecoverable_writing_error();
626 }
627 _requested_bottom = align_down(heap_end - heap_region_byte_size, alignment);
628 } else if (UseG1GC) {
629 // For G1, pick the range at the top of the current heap. If the exact same heap sizes
630 // are used in the production run, it's likely that we can map the archived objects
631 // at the requested location to avoid relocation.
632 address heap_end = (address)G1CollectedHeap::heap()->reserved().end();
633 log_info(aot, heap)("Heap end = %p", heap_end);
634 _requested_bottom = align_down(heap_end - heap_region_byte_size, G1HeapRegion::GrainBytes);
635 _requested_bottom = align_down(_requested_bottom, MIN_GC_REGION_ALIGNMENT);
636 assert(is_aligned(_requested_bottom, G1HeapRegion::GrainBytes), "sanity");
637 } else {
638 _requested_bottom = align_up(CompressedOops::begin(), MIN_GC_REGION_ALIGNMENT);
639 }
640 } else {
641 // We always write the objects as if the heap started at this address. This
642 // makes the contents of the archive heap deterministic.
643 //
644 // Note that at runtime, the heap address is selected by the OS, so the archive
645 // heap will not be mapped at 0x10000000, and the contents need to be patched.
646 _requested_bottom = align_up((address)NOCOOPS_REQUESTED_BASE, MIN_GC_REGION_ALIGNMENT);
647 }
648
649 assert(is_aligned(_requested_bottom, MIN_GC_REGION_ALIGNMENT), "sanity");
650
651 _requested_top = _requested_bottom + _buffer_used;
652
653 info->set_buffer_region(MemRegion(offset_to_buffered_address<HeapWord*>(0),
654 offset_to_buffered_address<HeapWord*>(_buffer_used)));
655 info->set_root_segments(_heap_root_segments);
656 }
657
658 // Oop relocation
659
660 template <typename T> T* AOTMappedHeapWriter::requested_addr_to_buffered_addr(T* p) {
661 assert(is_in_requested_range(cast_to_oop(p)), "must be");
662
663 address addr = address(p);
664 assert(addr >= _requested_bottom, "must be");
665 size_t offset = addr - _requested_bottom;
666 return offset_to_buffered_address<T*>(offset);
667 }
668
669 template <typename T> oop AOTMappedHeapWriter::load_source_oop_from_buffer(T* buffered_addr) {
670 oop o = load_oop_from_buffer(buffered_addr);
671 assert(!in_buffer(cast_from_oop<address>(o)), "must point to source oop");
672 return o;
673 }
674
675 template <typename T> void AOTMappedHeapWriter::store_requested_oop_in_buffer(T* buffered_addr,
676 oop request_oop) {
677 assert(request_oop == nullptr || is_in_requested_range(request_oop), "must be");
678 store_oop_in_buffer(buffered_addr, request_oop);
679 }
680
681 inline void AOTMappedHeapWriter::store_oop_in_buffer(oop* buffered_addr, oop requested_obj) {
682 *buffered_addr = requested_obj;
683 }
684
685 inline void AOTMappedHeapWriter::store_oop_in_buffer(narrowOop* buffered_addr, oop requested_obj) {
686 narrowOop val = CompressedOops::encode(requested_obj);
687 *buffered_addr = val;
688 }
689
690 oop AOTMappedHeapWriter::load_oop_from_buffer(oop* buffered_addr) {
691 return *buffered_addr;
692 }
693
694 oop AOTMappedHeapWriter::load_oop_from_buffer(narrowOop* buffered_addr) {
695 return CompressedOops::decode(*buffered_addr);
696 }
697
698 template <typename T> void AOTMappedHeapWriter::relocate_field_in_buffer(T* field_addr_in_buffer, oop source_referent, CHeapBitMap* oopmap) {
699 oop request_referent = source_obj_to_requested_obj(source_referent);
700 if (UseCompressedOops && is_writing_deterministic_heap()) {
701 // We use zero-based, 0-shift encoding, so the narrowOop is just the lower
702 // 32 bits of request_referent
703 intptr_t addr = cast_from_oop<intptr_t>(request_referent);
704 *((narrowOop*)field_addr_in_buffer) = checked_cast<narrowOop>(addr);
705 } else {
706 store_requested_oop_in_buffer<T>(field_addr_in_buffer, request_referent);
707 }
708 if (request_referent != nullptr) {
709 mark_oop_pointer<T>(field_addr_in_buffer, oopmap);
710 }
711 }
712
713 template <typename T> void AOTMappedHeapWriter::mark_oop_pointer(T* buffered_addr, CHeapBitMap* oopmap) {
714 T* request_p = (T*)(buffered_addr_to_requested_addr((address)buffered_addr));
715 address requested_region_bottom;
716
717 assert(request_p >= (T*)_requested_bottom, "sanity");
718 assert(request_p < (T*)_requested_top, "sanity");
719 requested_region_bottom = _requested_bottom;
720
721 // Mark the pointer in the oopmap
722 T* region_bottom = (T*)requested_region_bottom;
723 assert(request_p >= region_bottom, "must be");
724 BitMap::idx_t idx = request_p - region_bottom;
725 assert(idx < oopmap->size(), "overflow");
726 oopmap->set_bit(idx);
727 }
728
729 void AOTMappedHeapWriter::update_header_for_requested_obj(oop requested_obj, oop src_obj, Klass* src_klass) {
730 assert(UseCompressedClassPointers, "Archived heap only supported for compressed klasses");
731 narrowKlass nk = ArchiveBuilder::current()->get_requested_narrow_klass(src_klass);
732 address buffered_addr = requested_addr_to_buffered_addr(cast_from_oop<address>(requested_obj));
733
734 oop fake_oop = cast_to_oop(buffered_addr);
735 if (UseCompactObjectHeaders) {
736 fake_oop->set_mark(markWord::prototype().set_narrow_klass(nk));
737 assert(fake_oop->mark().narrow_klass() != 0, "must not be null");
738 } else {
739 fake_oop->set_narrow_klass(nk);
740 }
741
742 if (src_obj == nullptr) {
743 return;
744 }
745 // We need to retain the identity_hash, because it may have been used by some hashtables
746 // in the shared heap.
747 if (!src_obj->fast_no_hash_check()) {
748 intptr_t src_hash = src_obj->identity_hash();
749 if (UseCompactObjectHeaders) {
750 markWord m = markWord::prototype().set_narrow_klass(nk);
751 m = m.copy_hashctrl_from(src_obj->mark());
752 fake_oop->set_mark(m);
753 if (m.is_hashed_not_expanded()) {
754 fake_oop->set_mark(fake_oop->initialize_hash_if_necessary(src_obj, src_klass, m));
755 } else if (m.is_not_hashed_expanded()) {
756 fake_oop->set_mark(m.set_not_hashed_not_expanded());
757 }
758 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");
759 } else {
760 fake_oop->set_mark(markWord::prototype().copy_set_hash(src_hash));
761 DEBUG_ONLY(intptr_t archived_hash = fake_oop->identity_hash());
762 assert(src_hash == archived_hash, "Different hash codes: original " INTPTR_FORMAT ", archived " INTPTR_FORMAT, src_hash, archived_hash);
763 }
764 assert(fake_oop->mark().is_unlocked(), "sanity");
765 }
766 // Strip age bits.
767 fake_oop->set_mark(fake_oop->mark().set_age(0));
768 }
769
770 class AOTMappedHeapWriter::EmbeddedOopRelocator: public BasicOopIterateClosure {
771 oop _src_obj;
772 address _buffered_obj;
773 CHeapBitMap* _oopmap;
774 bool _is_java_lang_ref;
775 public:
776 EmbeddedOopRelocator(oop src_obj, address buffered_obj, CHeapBitMap* oopmap) :
777 _src_obj(src_obj), _buffered_obj(buffered_obj), _oopmap(oopmap)
778 {
779 _is_java_lang_ref = AOTReferenceObjSupport::check_if_ref_obj(src_obj);
780 }
781
782 void do_oop(narrowOop *p) { EmbeddedOopRelocator::do_oop_work(p); }
783 void do_oop( oop *p) { EmbeddedOopRelocator::do_oop_work(p); }
784
785 private:
786 template <class T> void do_oop_work(T *p) {
787 int field_offset = pointer_delta_as_int((char*)p, cast_from_oop<char*>(_src_obj));
788 T* field_addr = (T*)(_buffered_obj + field_offset);
789 oop referent = load_source_oop_from_buffer<T>(field_addr);
790 referent = HeapShared::maybe_remap_referent(_is_java_lang_ref, field_offset, referent);
791 AOTMappedHeapWriter::relocate_field_in_buffer<T>(field_addr, referent, _oopmap);
792 }
793 };
794
795 static void log_bitmap_usage(const char* which, BitMap* bitmap, size_t total_bits) {
796 // The whole heap is covered by total_bits, but there are only non-zero bits within [start ... end).
797 size_t start = bitmap->find_first_set_bit(0);
798 size_t end = bitmap->size();
799 log_info(aot)("%s = %7zu ... %7zu (%3zu%% ... %3zu%% = %3zu%%)", which,
800 start, end,
801 start * 100 / total_bits,
802 end * 100 / total_bits,
803 (end - start) * 100 / total_bits);
804 }
805
806 // Update all oop fields embedded in the buffered objects
807 void AOTMappedHeapWriter::relocate_embedded_oops(GrowableArrayCHeap<oop, mtClassShared>* roots,
808 ArchiveMappedHeapInfo* heap_info) {
809 size_t oopmap_unit = (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop));
810 size_t heap_region_byte_size = _buffer_used;
811 heap_info->oopmap()->resize(heap_region_byte_size / oopmap_unit);
812
813 for (int i = 0; i < _source_objs_order->length(); i++) {
814 int src_obj_index = _source_objs_order->at(i)._index;
815 oop src_obj = _source_objs->at(src_obj_index);
816 HeapShared::CachedOopInfo* info = HeapShared::get_cached_oop_info(src_obj);
817 assert(info != nullptr, "must be");
818 oop requested_obj = requested_obj_from_buffer_offset(info->buffer_offset());
819 update_header_for_requested_obj(requested_obj, src_obj, src_obj->klass());
820 address buffered_obj = offset_to_buffered_address<address>(info->buffer_offset());
821 EmbeddedOopRelocator relocator(src_obj, buffered_obj, heap_info->oopmap());
822 src_obj->oop_iterate(&relocator);
823 mark_native_pointers(src_obj);
824 };
825
826 // Relocate HeapShared::roots(), which is created in copy_roots_to_buffer() and
827 // doesn't have a corresponding src_obj, so we can't use EmbeddedOopRelocator on it.
828 for (size_t seg_idx = 0; seg_idx < _heap_root_segments.count(); seg_idx++) {
829 size_t seg_offset = _heap_root_segments.segment_offset(seg_idx);
830
831 objArrayOop requested_obj = (objArrayOop)requested_obj_from_buffer_offset(seg_offset);
832 update_header_for_requested_obj(requested_obj, nullptr, Universe::objectArrayKlass());
833 address buffered_obj = offset_to_buffered_address<address>(seg_offset);
834 int length = _heap_root_segments.size_in_elems(seg_idx);
835
836 size_t elem_size = UseCompressedOops ? sizeof(narrowOop) : sizeof(oop);
837
838 for (int i = 0; i < length; i++) {
839 // There is no source object; these are native oops - load, translate and
840 // write back
841 size_t elem_offset = objArrayOopDesc::base_offset_in_bytes() + elem_size * i;
842 HeapWord* elem_addr = (HeapWord*)(buffered_obj + elem_offset);
843 oop obj = NativeAccess<>::oop_load(elem_addr);
844 obj = HeapShared::maybe_remap_referent(false /* is_reference_field */, elem_offset, obj);
845 if (UseCompressedOops) {
846 relocate_field_in_buffer<narrowOop>((narrowOop*)elem_addr, obj, heap_info->oopmap());
847 } else {
848 relocate_field_in_buffer<oop>((oop*)elem_addr, obj, heap_info->oopmap());
849 }
850 }
851 }
852
853 compute_ptrmap(heap_info);
854
855 size_t total_bytes = (size_t)_buffer->length();
856 log_bitmap_usage("oopmap", heap_info->oopmap(), total_bytes / (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop)));
857 log_bitmap_usage("ptrmap", heap_info->ptrmap(), total_bytes / sizeof(address));
858 }
859
860 void AOTMappedHeapWriter::mark_native_pointer(oop src_obj, int field_offset) {
861 Metadata* ptr = src_obj->metadata_field_acquire(field_offset);
862 if (ptr != nullptr) {
863 NativePointerInfo info;
864 info._src_obj = src_obj;
865 info._field_offset = field_offset;
866 _native_pointers->append(info);
867 HeapShared::set_has_native_pointers(src_obj);
868 _num_native_ptrs ++;
869 }
870 }
871
872 void AOTMappedHeapWriter::mark_native_pointers(oop orig_obj) {
873 HeapShared::do_metadata_offsets(orig_obj, [&](int offset) {
874 mark_native_pointer(orig_obj, offset);
875 });
876 }
877
878 void AOTMappedHeapWriter::compute_ptrmap(ArchiveMappedHeapInfo* heap_info) {
879 int num_non_null_ptrs = 0;
880 Metadata** bottom = (Metadata**) _requested_bottom;
881 Metadata** top = (Metadata**) _requested_top; // exclusive
882 heap_info->ptrmap()->resize(top - bottom);
883
884 BitMap::idx_t max_idx = 32; // paranoid - don't make it too small
885 for (int i = 0; i < _native_pointers->length(); i++) {
886 NativePointerInfo info = _native_pointers->at(i);
887 oop src_obj = info._src_obj;
888 int field_offset = info._field_offset;
889 HeapShared::CachedOopInfo* p = HeapShared::get_cached_oop_info(src_obj);
890 // requested_field_addr = the address of this field in the requested space
891 oop requested_obj = requested_obj_from_buffer_offset(p->buffer_offset());
892 Metadata** requested_field_addr = (Metadata**)(cast_from_oop<address>(requested_obj) + field_offset);
893 assert(bottom <= requested_field_addr && requested_field_addr < top, "range check");
894
895 // Mark this field in the bitmap
896 BitMap::idx_t idx = requested_field_addr - bottom;
897 heap_info->ptrmap()->set_bit(idx);
898 num_non_null_ptrs ++;
899 max_idx = MAX2(max_idx, idx);
900
901 // Set the native pointer to the requested address of the metadata (at runtime, the metadata will have
902 // this address if the RO/RW regions are mapped at the default location).
903
904 Metadata** buffered_field_addr = requested_addr_to_buffered_addr(requested_field_addr);
905 Metadata* native_ptr = *buffered_field_addr;
906 guarantee(native_ptr != nullptr, "sanity");
907
908 if (RegeneratedClasses::has_been_regenerated(native_ptr)) {
909 native_ptr = RegeneratedClasses::get_regenerated_object(native_ptr);
910 }
911
912 guarantee(ArchiveBuilder::current()->has_been_archived((address)native_ptr),
913 "Metadata %p should have been archived", native_ptr);
914
915 address buffered_native_ptr = ArchiveBuilder::current()->get_buffered_addr((address)native_ptr);
916 address requested_native_ptr = ArchiveBuilder::current()->to_requested(buffered_native_ptr);
917 *buffered_field_addr = (Metadata*)requested_native_ptr;
918 }
919
920 heap_info->ptrmap()->resize(max_idx + 1);
921 log_info(aot, heap)("calculate_ptrmap: marked %d non-null native pointers for heap region (%zu bits)",
922 num_non_null_ptrs, size_t(heap_info->ptrmap()->size()));
923 }
924
925 AOTMapLogger::OopDataIterator* AOTMappedHeapWriter::oop_iterator(ArchiveMappedHeapInfo* heap_info) {
926 class MappedWriterOopIterator : public AOTMapLogger::OopDataIterator {
927 private:
928 address _current;
929 address _next;
930
931 address _buffer_start;
932 address _buffer_end;
933 uint64_t _buffer_start_narrow_oop;
934 intptr_t _buffer_to_requested_delta;
935 int _requested_shift;
936
937 size_t _num_root_segments;
938 size_t _num_obj_arrays_logged;
939
940 public:
941 MappedWriterOopIterator(address buffer_start,
942 address buffer_end,
943 uint64_t buffer_start_narrow_oop,
944 intptr_t buffer_to_requested_delta,
945 int requested_shift,
946 size_t num_root_segments)
947 : _current(nullptr),
948 _next(buffer_start),
949 _buffer_start(buffer_start),
950 _buffer_end(buffer_end),
951 _buffer_start_narrow_oop(buffer_start_narrow_oop),
952 _buffer_to_requested_delta(buffer_to_requested_delta),
953 _requested_shift(requested_shift),
954 _num_root_segments(num_root_segments),
955 _num_obj_arrays_logged(0) {
956 }
957
958 AOTMapLogger::OopData capture(address buffered_addr) {
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 bool has_next() override {
978 return _next < _buffer_end;
979 }
980
981 AOTMapLogger::OopData next() override {
982 _current = _next;
983 AOTMapLogger::OopData result = capture(_current);
984 if (result._klass->is_objArray_klass()) {
985 result._is_root_segment = _num_obj_arrays_logged++ < _num_root_segments;
986 }
987 _next = _current + result._size * BytesPerWord;
988 return result;
989 }
990
991 AOTMapLogger::OopData obj_at(narrowOop* addr) override {
992 uint64_t n = (uint64_t)(*addr);
993 if (n == 0) {
994 return null_data();
995 } else {
996 precond(n >= _buffer_start_narrow_oop);
997 address buffer_addr = _buffer_start + ((n - _buffer_start_narrow_oop) << _requested_shift);
998 return capture(buffer_addr);
999 }
1000 }
1001
1002 AOTMapLogger::OopData obj_at(oop* addr) override {
1003 address requested_value = cast_from_oop<address>(*addr);
1004 if (requested_value == nullptr) {
1005 return null_data();
1006 } else {
1007 address buffer_addr = requested_value - _buffer_to_requested_delta;
1008 return capture(buffer_addr);
1009 }
1010 }
1011
1012 GrowableArrayCHeap<AOTMapLogger::OopData, mtClass>* roots() override {
1013 return new GrowableArrayCHeap<AOTMapLogger::OopData, mtClass>();
1014 }
1015 };
1016
1017 MemRegion r = heap_info->buffer_region();
1018 address buffer_start = address(r.start());
1019 address buffer_end = address(r.end());
1020
1021 address requested_base = UseCompressedOops ? AOTMappedHeapWriter::narrow_oop_base() : (address)AOTMappedHeapWriter::NOCOOPS_REQUESTED_BASE;
1022 address requested_start = UseCompressedOops ? AOTMappedHeapWriter::buffered_addr_to_requested_addr(buffer_start) : requested_base;
1023 int requested_shift = AOTMappedHeapWriter::narrow_oop_shift();
1024 intptr_t buffer_to_requested_delta = requested_start - buffer_start;
1025 uint64_t buffer_start_narrow_oop = 0xdeadbeed;
1026 if (UseCompressedOops) {
1027 buffer_start_narrow_oop = (uint64_t)(pointer_delta(requested_start, requested_base, 1)) >> requested_shift;
1028 assert(buffer_start_narrow_oop < 0xffffffff, "sanity");
1029 }
1030
1031 return new MappedWriterOopIterator(buffer_start,
1032 buffer_end,
1033 buffer_start_narrow_oop,
1034 buffer_to_requested_delta,
1035 requested_shift,
1036 heap_info->root_segments().count());
1037 }
1038
1039 #endif // INCLUDE_CDS_JAVA_HEAP