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 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 // Keep track of the contents of the archived interned string table. This table
185 // is used only by CDSHeapVerifier.
186 void AOTMappedHeapWriter::add_to_dumped_interned_strings(oop string) {
187 assert_at_safepoint(); // DumpedInternedStrings uses raw oops
188 assert(!is_string_too_large_to_archive(string), "must be");
189 bool created;
190 _dumped_interned_strings->put_if_absent(string, true, &created);
191 if (created) {
192 // Prevent string deduplication from changing the value field to
193 // something not in the archive.
194 java_lang_String::set_deduplication_forbidden(string);
195 _dumped_interned_strings->maybe_grow();
196 }
197 }
198
199 bool AOTMappedHeapWriter::is_dumped_interned_string(oop o) {
200 return _dumped_interned_strings->get(o) != nullptr;
201 }
202
203 // Various lookup functions between source_obj, buffered_obj and requested_obj
204 bool AOTMappedHeapWriter::is_in_requested_range(oop o) {
205 assert(_requested_bottom != nullptr, "do not call before _requested_bottom is initialized");
206 address a = cast_from_oop<address>(o);
207 return (_requested_bottom <= a && a < _requested_top);
208 }
209
210 oop AOTMappedHeapWriter::requested_obj_from_buffer_offset(size_t offset) {
211 oop req_obj = cast_to_oop(_requested_bottom + offset);
212 assert(is_in_requested_range(req_obj), "must be");
213 return req_obj;
214 }
215
216 oop AOTMappedHeapWriter::source_obj_to_requested_obj(oop src_obj) {
217 assert(CDSConfig::is_dumping_heap(), "dump-time only");
218 HeapShared::CachedOopInfo* p = HeapShared::get_cached_oop_info(src_obj);
219 if (p != nullptr) {
220 return requested_obj_from_buffer_offset(p->buffer_offset());
221 } else {
222 return nullptr;
223 }
224 }
225
226 oop AOTMappedHeapWriter::buffered_addr_to_source_obj(address buffered_addr) {
227 OopHandle* oh = _buffer_offset_to_source_obj_table->get(buffered_address_to_offset(buffered_addr));
228 if (oh != nullptr) {
229 return oh->resolve();
230 } else {
231 return nullptr;
232 }
233 }
234
235 Klass* AOTMappedHeapWriter::real_klass_of_buffered_oop(address buffered_addr) {
236 oop p = buffered_addr_to_source_obj(buffered_addr);
237 if (p != nullptr) {
238 return p->klass();
239 } else if (get_filler_size_at(buffered_addr) > 0) {
240 return Universe::fillerArrayKlass();
241 } else {
242 // This is one of the root segments
243 return Universe::objectArrayKlass();
244 }
245 }
246
247 size_t AOTMappedHeapWriter::size_of_buffered_oop(address buffered_addr) {
248 oop p = buffered_addr_to_source_obj(buffered_addr);
249 if (p != nullptr) {
250 return p->size();
251 }
252
253 size_t nbytes = get_filler_size_at(buffered_addr);
254 if (nbytes > 0) {
255 assert((nbytes % BytesPerWord) == 0, "should be aligned");
256 return nbytes / BytesPerWord;
257 }
258
259 address hrs = buffer_bottom();
260 for (size_t seg_idx = 0; seg_idx < _heap_root_segments.count(); seg_idx++) {
261 nbytes = _heap_root_segments.size_in_bytes(seg_idx);
262 if (hrs == buffered_addr) {
263 assert((nbytes % BytesPerWord) == 0, "should be aligned");
264 return nbytes / BytesPerWord;
265 }
266 hrs += nbytes;
267 }
268
269 ShouldNotReachHere();
270 return 0;
271 }
272
273 address AOTMappedHeapWriter::buffered_addr_to_requested_addr(address buffered_addr) {
274 return _requested_bottom + buffered_address_to_offset(buffered_addr);
275 }
276
277 address AOTMappedHeapWriter::requested_address() {
278 assert(_buffer != nullptr, "must be initialized");
279 return _requested_bottom;
280 }
281
282 void AOTMappedHeapWriter::allocate_buffer() {
283 int initial_buffer_size = 100000;
284 _buffer = new GrowableArrayCHeap<u1, mtClassShared>(initial_buffer_size);
285 _buffer_used = 0;
286 ensure_buffer_space(1); // so that buffer_bottom() works
287 }
288
289 void AOTMappedHeapWriter::ensure_buffer_space(size_t min_bytes) {
290 // We usually have very small heaps. If we get a huge one it's probably caused by a bug.
291 guarantee(min_bytes <= max_jint, "we dont support archiving more than 2G of objects");
292 _buffer->at_grow(to_array_index(min_bytes));
293 }
294
295 objArrayOop AOTMappedHeapWriter::allocate_root_segment(size_t offset, int element_count) {
296 HeapWord* mem = offset_to_buffered_address<HeapWord *>(offset);
297 memset(mem, 0, refArrayOopDesc::object_size(element_count));
298
299 // The initialization code is copied from MemAllocator::finish and ObjArrayAllocator::initialize.
300 if (UseCompactObjectHeaders) {
301 oopDesc::release_set_mark(mem, Universe::objectArrayKlass()->prototype_header());
302 } else {
303 assert(!EnableValhalla || Universe::objectArrayKlass()->prototype_header() == markWord::prototype(), "should be the same");
304 oopDesc::set_mark(mem, markWord::prototype());
305 oopDesc::release_set_klass(mem, Universe::objectArrayKlass());
306 }
307 arrayOopDesc::set_length(mem, element_count);
308 return objArrayOop(cast_to_oop(mem));
309 }
310
311 void AOTMappedHeapWriter::root_segment_at_put(objArrayOop segment, int index, oop root) {
312 // Do not use arrayOop->obj_at_put(i, o) as arrayOop is outside the real heap!
313 if (UseCompressedOops) {
314 *segment->obj_at_addr<narrowOop>(index) = CompressedOops::encode(root);
315 } else {
316 *segment->obj_at_addr<oop>(index) = root;
317 }
318 }
319
320 void AOTMappedHeapWriter::copy_roots_to_buffer(GrowableArrayCHeap<oop, mtClassShared>* roots) {
321 // Depending on the number of classes we are archiving, a single roots array may be
322 // larger than MIN_GC_REGION_ALIGNMENT. Roots are allocated first in the buffer, which
323 // allows us to chop the large array into a series of "segments". Current layout
324 // starts with zero or more segments exactly fitting MIN_GC_REGION_ALIGNMENT, and end
325 // with a single segment that may be smaller than MIN_GC_REGION_ALIGNMENT.
326 // This is simple and efficient. We do not need filler objects anywhere between the segments,
327 // or immediately after the last segment. This allows starting the object dump immediately
328 // after the roots.
329
330 assert((_buffer_used % MIN_GC_REGION_ALIGNMENT) == 0,
331 "Pre-condition: Roots start at aligned boundary: %zu", _buffer_used);
332
333 int max_elem_count = ((MIN_GC_REGION_ALIGNMENT - arrayOopDesc::header_size_in_bytes()) / heapOopSize);
334 assert(refArrayOopDesc::object_size(max_elem_count)*HeapWordSize == MIN_GC_REGION_ALIGNMENT,
335 "Should match exactly");
336
337 HeapRootSegments segments(_buffer_used,
338 roots->length(),
339 MIN_GC_REGION_ALIGNMENT,
340 max_elem_count);
341
342 int root_index = 0;
343 for (size_t seg_idx = 0; seg_idx < segments.count(); seg_idx++) {
344 int size_elems = segments.size_in_elems(seg_idx);
345 size_t size_bytes = segments.size_in_bytes(seg_idx);
346
347 size_t oop_offset = _buffer_used;
348 _buffer_used = oop_offset + size_bytes;
349 ensure_buffer_space(_buffer_used);
350
351 assert((oop_offset % MIN_GC_REGION_ALIGNMENT) == 0,
352 "Roots segment %zu start is not aligned: %zu",
353 segments.count(), oop_offset);
354
355 objArrayOop seg_oop = allocate_root_segment(oop_offset, size_elems);
356 for (int i = 0; i < size_elems; i++) {
357 root_segment_at_put(seg_oop, i, roots->at(root_index++));
358 }
359
360 log_info(aot, heap)("archived obj root segment [%d] = %zu bytes, obj = " PTR_FORMAT,
361 size_elems, size_bytes, p2i(seg_oop));
362 }
363
364 assert(root_index == roots->length(), "Post-condition: All roots are handled");
365
366 _heap_root_segments = segments;
367 }
368
369 // The goal is to sort the objects in increasing order of:
370 // - objects that have only oop pointers
371 // - objects that have both native and oop pointers
372 // - objects that have only native pointers
373 // - objects that have no pointers
374 static int oop_sorting_rank(oop o) {
375 bool has_oop_ptr, has_native_ptr;
376 HeapShared::get_pointer_info(o, has_oop_ptr, has_native_ptr);
377
378 if (has_oop_ptr) {
379 if (!has_native_ptr) {
380 return 0;
381 } else {
382 return 1;
383 }
384 } else {
385 if (has_native_ptr) {
386 return 2;
387 } else {
388 return 3;
389 }
390 }
391 }
392
393 int AOTMappedHeapWriter::compare_objs_by_oop_fields(HeapObjOrder* a, HeapObjOrder* b) {
394 int rank_a = a->_rank;
395 int rank_b = b->_rank;
396
397 if (rank_a != rank_b) {
398 return rank_a - rank_b;
399 } else {
400 // If they are the same rank, sort them by their position in the _source_objs array
401 return a->_index - b->_index;
402 }
403 }
404
405 void AOTMappedHeapWriter::sort_source_objs() {
406 log_info(aot)("sorting heap objects");
407 int len = _source_objs->length();
408 _source_objs_order = new GrowableArrayCHeap<HeapObjOrder, mtClassShared>(len);
409
410 for (int i = 0; i < len; i++) {
411 oop o = _source_objs->at(i);
412 int rank = oop_sorting_rank(o);
413 HeapObjOrder os = {i, rank};
414 _source_objs_order->append(os);
415 }
416 log_info(aot)("computed ranks");
417 _source_objs_order->sort(compare_objs_by_oop_fields);
418 log_info(aot)("sorting heap objects done");
419 }
420
421 void AOTMappedHeapWriter::copy_source_objs_to_buffer(GrowableArrayCHeap<oop, mtClassShared>* roots) {
422 // There could be multiple root segments, which we want to be aligned by region.
423 // Putting them ahead of objects makes sure we waste no space.
424 copy_roots_to_buffer(roots);
425
426 sort_source_objs();
427 for (int i = 0; i < _source_objs_order->length(); i++) {
428 int src_obj_index = _source_objs_order->at(i)._index;
429 oop src_obj = _source_objs->at(src_obj_index);
430 HeapShared::CachedOopInfo* info = HeapShared::get_cached_oop_info(src_obj);
431 assert(info != nullptr, "must be");
432 size_t buffer_offset = copy_one_source_obj_to_buffer(src_obj);
433 info->set_buffer_offset(buffer_offset);
434
435 OopHandle handle(Universe::vm_global(), src_obj);
436 _buffer_offset_to_source_obj_table->put_when_absent(buffer_offset, handle);
437 _buffer_offset_to_source_obj_table->maybe_grow();
438
439 if (java_lang_Module::is_instance(src_obj)) {
440 Modules::check_archived_module_oop(src_obj);
441 }
442 }
443
444 log_info(aot)("Size of heap region = %zu bytes, %d objects, %d roots, %d native ptrs",
445 _buffer_used, _source_objs->length() + 1, roots->length(), _num_native_ptrs);
446 }
447
448 size_t AOTMappedHeapWriter::filler_array_byte_size(int length) {
449 size_t byte_size = refArrayOopDesc::object_size(length) * HeapWordSize;
450 return byte_size;
451 }
452
453 int AOTMappedHeapWriter::filler_array_length(size_t fill_bytes) {
454 assert(is_object_aligned(fill_bytes), "must be");
455 size_t elemSize = (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop));
456
457 int initial_length = to_array_length(fill_bytes / elemSize);
458 for (int length = initial_length; length >= 0; length --) {
459 size_t array_byte_size = filler_array_byte_size(length);
460 if (array_byte_size == fill_bytes) {
461 return length;
462 }
463 }
464
465 ShouldNotReachHere();
466 return -1;
467 }
468
469 HeapWord* AOTMappedHeapWriter::init_filler_array_at_buffer_top(int array_length, size_t fill_bytes) {
470 assert(UseCompressedClassPointers, "Archived heap only supported for compressed klasses");
471 Klass* oak = Universe::objectArrayKlass(); // already relocated to point to archived klass
472 HeapWord* mem = offset_to_buffered_address<HeapWord*>(_buffer_used);
473 memset(mem, 0, fill_bytes);
474 narrowKlass nk = ArchiveBuilder::current()->get_requested_narrow_klass(oak);
475 if (UseCompactObjectHeaders) {
476 oopDesc::release_set_mark(mem, markWord::prototype().set_narrow_klass(nk));
477 } else {
478 oopDesc::set_mark(mem, markWord::prototype());
479 cast_to_oop(mem)->set_narrow_klass(nk);
480 }
481 arrayOopDesc::set_length(mem, array_length);
482 return mem;
483 }
484
485 void AOTMappedHeapWriter::maybe_fill_gc_region_gap(size_t required_byte_size) {
486 // We fill only with arrays (so we don't need to use a single HeapWord filler if the
487 // leftover space is smaller than a zero-sized array object). Therefore, we need to
488 // make sure there's enough space of min_filler_byte_size in the current region after
489 // required_byte_size has been allocated. If not, fill the remainder of the current
490 // region.
491 size_t min_filler_byte_size = filler_array_byte_size(0);
492 size_t new_used = _buffer_used + required_byte_size + min_filler_byte_size;
493
494 const size_t cur_min_region_bottom = align_down(_buffer_used, MIN_GC_REGION_ALIGNMENT);
495 const size_t next_min_region_bottom = align_down(new_used, MIN_GC_REGION_ALIGNMENT);
496
497 if (cur_min_region_bottom != next_min_region_bottom) {
498 // Make sure that no objects span across MIN_GC_REGION_ALIGNMENT. This way
499 // we can map the region in any region-based collector.
500 assert(next_min_region_bottom > cur_min_region_bottom, "must be");
501 assert(next_min_region_bottom - cur_min_region_bottom == MIN_GC_REGION_ALIGNMENT,
502 "no buffered object can be larger than %d bytes", MIN_GC_REGION_ALIGNMENT);
503
504 const size_t filler_end = next_min_region_bottom;
505 const size_t fill_bytes = filler_end - _buffer_used;
506 assert(fill_bytes > 0, "must be");
507 ensure_buffer_space(filler_end);
508
509 int array_length = filler_array_length(fill_bytes);
510 log_info(aot, heap)("Inserting filler obj array of %d elements (%zu bytes total) @ buffer offset %zu",
511 array_length, fill_bytes, _buffer_used);
512 HeapWord* filler = init_filler_array_at_buffer_top(array_length, fill_bytes);
513 _buffer_used = filler_end;
514 _fillers->put(buffered_address_to_offset((address)filler), fill_bytes);
515 }
516 }
517
518 size_t AOTMappedHeapWriter::get_filler_size_at(address buffered_addr) {
519 size_t* p = _fillers->get(buffered_address_to_offset(buffered_addr));
520 if (p != nullptr) {
521 assert(*p > 0, "filler must be larger than zero bytes");
522 return *p;
523 } else {
524 return 0; // buffered_addr is not a filler
525 }
526 }
527
528 template <typename T>
529 void update_buffered_object_field(address buffered_obj, int field_offset, T value) {
530 T* field_addr = cast_to_oop(buffered_obj)->field_addr<T>(field_offset);
531 *field_addr = value;
532 }
533
534 size_t AOTMappedHeapWriter::copy_one_source_obj_to_buffer(oop src_obj) {
535 assert(!is_too_large_to_archive(src_obj), "already checked");
536 size_t byte_size = src_obj->size() * HeapWordSize;
537 assert(byte_size > 0, "no zero-size objects");
538
539 // For region-based collectors such as G1, the archive heap may be mapped into
540 // multiple regions. We need to make sure that we don't have an object that can possible
541 // span across two regions.
542 maybe_fill_gc_region_gap(byte_size);
543
544 size_t new_used = _buffer_used + byte_size;
545 assert(new_used > _buffer_used, "no wrap around");
546
547 size_t cur_min_region_bottom = align_down(_buffer_used, MIN_GC_REGION_ALIGNMENT);
548 size_t next_min_region_bottom = align_down(new_used, MIN_GC_REGION_ALIGNMENT);
549 assert(cur_min_region_bottom == next_min_region_bottom, "no object should cross minimal GC region boundaries");
550
551 ensure_buffer_space(new_used);
552
553 address from = cast_from_oop<address>(src_obj);
554 address to = offset_to_buffered_address<address>(_buffer_used);
555 assert(is_object_aligned(_buffer_used), "sanity");
556 assert(is_object_aligned(byte_size), "sanity");
557 memcpy(to, from, byte_size);
558
559 // These native pointers will be restored explicitly at run time.
560 if (java_lang_Module::is_instance(src_obj)) {
561 update_buffered_object_field<ModuleEntry*>(to, java_lang_Module::module_entry_offset(), nullptr);
562 } else if (java_lang_ClassLoader::is_instance(src_obj)) {
563 #ifdef ASSERT
564 // We only archive these loaders
565 if (src_obj != SystemDictionary::java_platform_loader() &&
566 src_obj != SystemDictionary::java_system_loader()) {
567 assert(src_obj->klass()->name()->equals("jdk/internal/loader/ClassLoaders$BootClassLoader"), "must be");
568 }
569 #endif
570 update_buffered_object_field<ClassLoaderData*>(to, java_lang_ClassLoader::loader_data_offset(), nullptr);
571 }
572
573 size_t buffered_obj_offset = _buffer_used;
574 _buffer_used = new_used;
575
576 return buffered_obj_offset;
577 }
578
579 // Set the range [_requested_bottom, _requested_top), the requested address range of all
580 // the archived heap objects in the production run.
581 //
582 // (1) UseCompressedOops == true && !is_writing_deterministic_heap()
583 //
584 // The archived objects are stored using the COOPS encoding of the assembly phase.
585 // We pick a range within the heap used by the assembly phase.
586 //
587 // In the production run, if different COOPS encodings are used:
588 // - The heap contents needs to be relocated.
589 //
590 // (2) UseCompressedOops == true && is_writing_deterministic_heap()
591 //
592 // We always use zero-based, zero-shift encoding. _requested_top is aligned to 0x10000000.
593 //
594 // (3) UseCompressedOops == false:
595 //
596 // In the production run, the heap range is usually picked (randomly) by the OS, so we
597 // will almost always need to perform relocation, regardless of how we pick the requested
598 // address range.
599 //
600 // So we just hard code it to NOCOOPS_REQUESTED_BASE.
601 //
602 void AOTMappedHeapWriter::set_requested_address_range(ArchiveMappedHeapInfo* info) {
603 assert(!info->is_used(), "only set once");
604
605 size_t heap_region_byte_size = _buffer_used;
606 assert(heap_region_byte_size > 0, "must archived at least one object!");
607
608 if (UseCompressedOops) {
609 if (is_writing_deterministic_heap()) {
610 // Pick a heap range so that requested addresses can be encoded with zero-base/no shift.
611 // We align the requested bottom to at least 1 MB: if the production run uses G1 with a small
612 // heap (e.g., -Xmx256m), it's likely that we can map the archived objects at the
613 // requested location to avoid relocation.
614 //
615 // For other collectors or larger heaps, relocation is unavoidable, but is usually
616 // quite cheap. If you really want to avoid relocation, use the AOT workflow instead.
617 address heap_end = (address)0x100000000;
618 size_t alignment = MAX2(MIN_GC_REGION_ALIGNMENT, 1024 * 1024);
619 if (align_up(heap_region_byte_size, alignment) >= (size_t)heap_end) {
620 log_error(aot, heap)("cached heap space is too large: %zu bytes", heap_region_byte_size);
621 AOTMetaspace::unrecoverable_writing_error();
622 }
623 _requested_bottom = align_down(heap_end - heap_region_byte_size, alignment);
624 } else if (UseG1GC) {
625 // For G1, pick the range at the top of the current heap. If the exact same heap sizes
626 // are used in the production run, it's likely that we can map the archived objects
627 // at the requested location to avoid relocation.
628 address heap_end = (address)G1CollectedHeap::heap()->reserved().end();
629 log_info(aot, heap)("Heap end = %p", heap_end);
630 _requested_bottom = align_down(heap_end - heap_region_byte_size, G1HeapRegion::GrainBytes);
631 _requested_bottom = align_down(_requested_bottom, MIN_GC_REGION_ALIGNMENT);
632 assert(is_aligned(_requested_bottom, G1HeapRegion::GrainBytes), "sanity");
633 } else {
634 _requested_bottom = align_up(CompressedOops::begin(), MIN_GC_REGION_ALIGNMENT);
635 }
636 } else {
637 // We always write the objects as if the heap started at this address. This
638 // makes the contents of the archive heap deterministic.
639 //
640 // Note that at runtime, the heap address is selected by the OS, so the archive
641 // heap will not be mapped at 0x10000000, and the contents need to be patched.
642 _requested_bottom = align_up((address)NOCOOPS_REQUESTED_BASE, MIN_GC_REGION_ALIGNMENT);
643 }
644
645 assert(is_aligned(_requested_bottom, MIN_GC_REGION_ALIGNMENT), "sanity");
646
647 _requested_top = _requested_bottom + _buffer_used;
648
649 info->set_buffer_region(MemRegion(offset_to_buffered_address<HeapWord*>(0),
650 offset_to_buffered_address<HeapWord*>(_buffer_used)));
651 info->set_root_segments(_heap_root_segments);
652 }
653
654 // Oop relocation
655
656 template <typename T> T* AOTMappedHeapWriter::requested_addr_to_buffered_addr(T* p) {
657 assert(is_in_requested_range(cast_to_oop(p)), "must be");
658
659 address addr = address(p);
660 assert(addr >= _requested_bottom, "must be");
661 size_t offset = addr - _requested_bottom;
662 return offset_to_buffered_address<T*>(offset);
663 }
664
665 template <typename T> oop AOTMappedHeapWriter::load_source_oop_from_buffer(T* buffered_addr) {
666 oop o = load_oop_from_buffer(buffered_addr);
667 assert(!in_buffer(cast_from_oop<address>(o)), "must point to source oop");
668 return o;
669 }
670
671 template <typename T> void AOTMappedHeapWriter::store_requested_oop_in_buffer(T* buffered_addr,
672 oop request_oop) {
673 assert(request_oop == nullptr || is_in_requested_range(request_oop), "must be");
674 store_oop_in_buffer(buffered_addr, request_oop);
675 }
676
677 inline void AOTMappedHeapWriter::store_oop_in_buffer(oop* buffered_addr, oop requested_obj) {
678 *buffered_addr = requested_obj;
679 }
680
681 inline void AOTMappedHeapWriter::store_oop_in_buffer(narrowOop* buffered_addr, oop requested_obj) {
682 narrowOop val = CompressedOops::encode(requested_obj);
683 *buffered_addr = val;
684 }
685
686 oop AOTMappedHeapWriter::load_oop_from_buffer(oop* buffered_addr) {
687 return *buffered_addr;
688 }
689
690 oop AOTMappedHeapWriter::load_oop_from_buffer(narrowOop* buffered_addr) {
691 return CompressedOops::decode(*buffered_addr);
692 }
693
694 template <typename T> void AOTMappedHeapWriter::relocate_field_in_buffer(T* field_addr_in_buffer, oop source_referent, CHeapBitMap* oopmap) {
695 oop request_referent = source_obj_to_requested_obj(source_referent);
696 if (UseCompressedOops && is_writing_deterministic_heap()) {
697 // We use zero-based, 0-shift encoding, so the narrowOop is just the lower
698 // 32 bits of request_referent
699 intptr_t addr = cast_from_oop<intptr_t>(request_referent);
700 *((narrowOop*)field_addr_in_buffer) = checked_cast<narrowOop>(addr);
701 } else {
702 store_requested_oop_in_buffer<T>(field_addr_in_buffer, request_referent);
703 }
704 if (request_referent != nullptr) {
705 mark_oop_pointer<T>(field_addr_in_buffer, oopmap);
706 }
707 }
708
709 template <typename T> void AOTMappedHeapWriter::mark_oop_pointer(T* buffered_addr, CHeapBitMap* oopmap) {
710 T* request_p = (T*)(buffered_addr_to_requested_addr((address)buffered_addr));
711 address requested_region_bottom;
712
713 assert(request_p >= (T*)_requested_bottom, "sanity");
714 assert(request_p < (T*)_requested_top, "sanity");
715 requested_region_bottom = _requested_bottom;
716
717 // Mark the pointer in the oopmap
718 T* region_bottom = (T*)requested_region_bottom;
719 assert(request_p >= region_bottom, "must be");
720 BitMap::idx_t idx = request_p - region_bottom;
721 assert(idx < oopmap->size(), "overflow");
722 oopmap->set_bit(idx);
723 }
724
725 void AOTMappedHeapWriter::update_header_for_requested_obj(oop requested_obj, oop src_obj, Klass* src_klass) {
726 assert(UseCompressedClassPointers, "Archived heap only supported for compressed klasses");
727 narrowKlass nk = ArchiveBuilder::current()->get_requested_narrow_klass(src_klass);
728 address buffered_addr = requested_addr_to_buffered_addr(cast_from_oop<address>(requested_obj));
729
730 oop fake_oop = cast_to_oop(buffered_addr);
731 if (UseCompactObjectHeaders) {
732 fake_oop->set_mark(markWord::prototype().set_narrow_klass(nk));
733 } else {
734 fake_oop->set_narrow_klass(nk);
735 }
736
737 if (src_obj == nullptr) {
738 return;
739 }
740 // We need to retain the identity_hash, because it may have been used by some hashtables
741 // in the shared heap.
742 if (!src_obj->fast_no_hash_check() && (!(EnableValhalla && src_obj->mark().is_inline_type()))) {
743 intptr_t src_hash = src_obj->identity_hash();
744 if (UseCompactObjectHeaders) {
745 fake_oop->set_mark(markWord::prototype().set_narrow_klass(nk).copy_set_hash(src_hash));
746 } else if (EnableValhalla) {
747 fake_oop->set_mark(src_klass->prototype_header().copy_set_hash(src_hash));
748 } else {
749 fake_oop->set_mark(markWord::prototype().copy_set_hash(src_hash));
750 }
751 assert(fake_oop->mark().is_unlocked(), "sanity");
752
753 DEBUG_ONLY(intptr_t archived_hash = fake_oop->identity_hash());
754 assert(src_hash == archived_hash, "Different hash codes: original " INTPTR_FORMAT ", archived " INTPTR_FORMAT, src_hash, archived_hash);
755 }
756 // Strip age bits.
757 fake_oop->set_mark(fake_oop->mark().set_age(0));
758 }
759
760 class AOTMappedHeapWriter::EmbeddedOopRelocator: public BasicOopIterateClosure {
761 oop _src_obj;
762 address _buffered_obj;
763 CHeapBitMap* _oopmap;
764 bool _is_java_lang_ref;
765 public:
766 EmbeddedOopRelocator(oop src_obj, address buffered_obj, CHeapBitMap* oopmap) :
767 _src_obj(src_obj), _buffered_obj(buffered_obj), _oopmap(oopmap)
768 {
769 _is_java_lang_ref = AOTReferenceObjSupport::check_if_ref_obj(src_obj);
770 }
771
772 void do_oop(narrowOop *p) { EmbeddedOopRelocator::do_oop_work(p); }
773 void do_oop( oop *p) { EmbeddedOopRelocator::do_oop_work(p); }
774
775 private:
776 template <class T> void do_oop_work(T *p) {
777 int field_offset = pointer_delta_as_int((char*)p, cast_from_oop<char*>(_src_obj));
778 T* field_addr = (T*)(_buffered_obj + field_offset);
779 oop referent = load_source_oop_from_buffer<T>(field_addr);
780 referent = HeapShared::maybe_remap_referent(_is_java_lang_ref, field_offset, referent);
781 AOTMappedHeapWriter::relocate_field_in_buffer<T>(field_addr, referent, _oopmap);
782 }
783 };
784
785 static void log_bitmap_usage(const char* which, BitMap* bitmap, size_t total_bits) {
786 // The whole heap is covered by total_bits, but there are only non-zero bits within [start ... end).
787 size_t start = bitmap->find_first_set_bit(0);
788 size_t end = bitmap->size();
789 log_info(aot)("%s = %7zu ... %7zu (%3zu%% ... %3zu%% = %3zu%%)", which,
790 start, end,
791 start * 100 / total_bits,
792 end * 100 / total_bits,
793 (end - start) * 100 / total_bits);
794 }
795
796 // Update all oop fields embedded in the buffered objects
797 void AOTMappedHeapWriter::relocate_embedded_oops(GrowableArrayCHeap<oop, mtClassShared>* roots,
798 ArchiveMappedHeapInfo* heap_info) {
799 size_t oopmap_unit = (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop));
800 size_t heap_region_byte_size = _buffer_used;
801 heap_info->oopmap()->resize(heap_region_byte_size / oopmap_unit);
802
803 for (int i = 0; i < _source_objs_order->length(); i++) {
804 int src_obj_index = _source_objs_order->at(i)._index;
805 oop src_obj = _source_objs->at(src_obj_index);
806 HeapShared::CachedOopInfo* info = HeapShared::get_cached_oop_info(src_obj);
807 assert(info != nullptr, "must be");
808 oop requested_obj = requested_obj_from_buffer_offset(info->buffer_offset());
809 update_header_for_requested_obj(requested_obj, src_obj, src_obj->klass());
810 address buffered_obj = offset_to_buffered_address<address>(info->buffer_offset());
811 EmbeddedOopRelocator relocator(src_obj, buffered_obj, heap_info->oopmap());
812 src_obj->oop_iterate(&relocator);
813 mark_native_pointers(src_obj);
814 };
815
816 // Relocate HeapShared::roots(), which is created in copy_roots_to_buffer() and
817 // doesn't have a corresponding src_obj, so we can't use EmbeddedOopRelocator on it.
818 for (size_t seg_idx = 0; seg_idx < _heap_root_segments.count(); seg_idx++) {
819 size_t seg_offset = _heap_root_segments.segment_offset(seg_idx);
820
821 objArrayOop requested_obj = (objArrayOop)requested_obj_from_buffer_offset(seg_offset);
822 update_header_for_requested_obj(requested_obj, nullptr, Universe::objectArrayKlass());
823 address buffered_obj = offset_to_buffered_address<address>(seg_offset);
824 int length = _heap_root_segments.size_in_elems(seg_idx);
825
826 size_t elem_size = UseCompressedOops ? sizeof(narrowOop) : sizeof(oop);
827
828 for (int i = 0; i < length; i++) {
829 // There is no source object; these are native oops - load, translate and
830 // write back
831 size_t elem_offset = objArrayOopDesc::base_offset_in_bytes() + elem_size * i;
832 HeapWord* elem_addr = (HeapWord*)(buffered_obj + elem_offset);
833 oop obj = NativeAccess<>::oop_load(elem_addr);
834 obj = HeapShared::maybe_remap_referent(false /* is_reference_field */, elem_offset, obj);
835 if (UseCompressedOops) {
836 relocate_field_in_buffer<narrowOop>((narrowOop*)elem_addr, obj, heap_info->oopmap());
837 } else {
838 relocate_field_in_buffer<oop>((oop*)elem_addr, obj, heap_info->oopmap());
839 }
840 }
841 }
842
843 compute_ptrmap(heap_info);
844
845 size_t total_bytes = (size_t)_buffer->length();
846 log_bitmap_usage("oopmap", heap_info->oopmap(), total_bytes / (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop)));
847 log_bitmap_usage("ptrmap", heap_info->ptrmap(), total_bytes / sizeof(address));
848 }
849
850 void AOTMappedHeapWriter::mark_native_pointer(oop src_obj, int field_offset) {
851 Metadata* ptr = src_obj->metadata_field_acquire(field_offset);
852 if (ptr != nullptr) {
853 NativePointerInfo info;
854 info._src_obj = src_obj;
855 info._field_offset = field_offset;
856 _native_pointers->append(info);
857 HeapShared::set_has_native_pointers(src_obj);
858 _num_native_ptrs ++;
859 }
860 }
861
862 void AOTMappedHeapWriter::mark_native_pointers(oop orig_obj) {
863 HeapShared::do_metadata_offsets(orig_obj, [&](int offset) {
864 mark_native_pointer(orig_obj, offset);
865 });
866 }
867
868 void AOTMappedHeapWriter::compute_ptrmap(ArchiveMappedHeapInfo* heap_info) {
869 int num_non_null_ptrs = 0;
870 Metadata** bottom = (Metadata**) _requested_bottom;
871 Metadata** top = (Metadata**) _requested_top; // exclusive
872 heap_info->ptrmap()->resize(top - bottom);
873
874 BitMap::idx_t max_idx = 32; // paranoid - don't make it too small
875 for (int i = 0; i < _native_pointers->length(); i++) {
876 NativePointerInfo info = _native_pointers->at(i);
877 oop src_obj = info._src_obj;
878 int field_offset = info._field_offset;
879 HeapShared::CachedOopInfo* p = HeapShared::get_cached_oop_info(src_obj);
880 // requested_field_addr = the address of this field in the requested space
881 oop requested_obj = requested_obj_from_buffer_offset(p->buffer_offset());
882 Metadata** requested_field_addr = (Metadata**)(cast_from_oop<address>(requested_obj) + field_offset);
883 assert(bottom <= requested_field_addr && requested_field_addr < top, "range check");
884
885 // Mark this field in the bitmap
886 BitMap::idx_t idx = requested_field_addr - bottom;
887 heap_info->ptrmap()->set_bit(idx);
888 num_non_null_ptrs ++;
889 max_idx = MAX2(max_idx, idx);
890
891 // Set the native pointer to the requested address of the metadata (at runtime, the metadata will have
892 // this address if the RO/RW regions are mapped at the default location).
893
894 Metadata** buffered_field_addr = requested_addr_to_buffered_addr(requested_field_addr);
895 Metadata* native_ptr = *buffered_field_addr;
896 guarantee(native_ptr != nullptr, "sanity");
897
898 if (RegeneratedClasses::has_been_regenerated(native_ptr)) {
899 native_ptr = RegeneratedClasses::get_regenerated_object(native_ptr);
900 }
901
902 guarantee(ArchiveBuilder::current()->has_been_archived((address)native_ptr),
903 "Metadata %p should have been archived", native_ptr);
904
905 address buffered_native_ptr = ArchiveBuilder::current()->get_buffered_addr((address)native_ptr);
906 address requested_native_ptr = ArchiveBuilder::current()->to_requested(buffered_native_ptr);
907 *buffered_field_addr = (Metadata*)requested_native_ptr;
908 }
909
910 heap_info->ptrmap()->resize(max_idx + 1);
911 log_info(aot, heap)("calculate_ptrmap: marked %d non-null native pointers for heap region (%zu bits)",
912 num_non_null_ptrs, size_t(heap_info->ptrmap()->size()));
913 }
914
915 AOTMapLogger::OopDataIterator* AOTMappedHeapWriter::oop_iterator(ArchiveMappedHeapInfo* heap_info) {
916 class MappedWriterOopIterator : public AOTMapLogger::OopDataIterator {
917 private:
918 address _current;
919 address _next;
920
921 address _buffer_start;
922 address _buffer_end;
923 uint64_t _buffer_start_narrow_oop;
924 intptr_t _buffer_to_requested_delta;
925 int _requested_shift;
926
927 size_t _num_root_segments;
928 size_t _num_obj_arrays_logged;
929
930 public:
931 MappedWriterOopIterator(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 size_t num_root_segments)
937 : _current(nullptr),
938 _next(buffer_start),
939 _buffer_start(buffer_start),
940 _buffer_end(buffer_end),
941 _buffer_start_narrow_oop(buffer_start_narrow_oop),
942 _buffer_to_requested_delta(buffer_to_requested_delta),
943 _requested_shift(requested_shift),
944 _num_root_segments(num_root_segments),
945 _num_obj_arrays_logged(0) {
946 }
947
948 AOTMapLogger::OopData capture(address buffered_addr) {
949 oopDesc* raw_oop = (oopDesc*)buffered_addr;
950 size_t size = size_of_buffered_oop(buffered_addr);
951 address requested_addr = buffered_addr_to_requested_addr(buffered_addr);
952 intptr_t target_location = (intptr_t)requested_addr;
953 uint64_t pd = (uint64_t)(pointer_delta(buffered_addr, _buffer_start, 1));
954 uint32_t narrow_location = checked_cast<uint32_t>(_buffer_start_narrow_oop + (pd >> _requested_shift));
955 Klass* klass = real_klass_of_buffered_oop(buffered_addr);
956
957 return { buffered_addr,
958 requested_addr,
959 target_location,
960 narrow_location,
961 raw_oop,
962 klass,
963 size,
964 false };
965 }
966
967 bool has_next() override {
968 return _next < _buffer_end;
969 }
970
971 AOTMapLogger::OopData next() override {
972 _current = _next;
973 AOTMapLogger::OopData result = capture(_current);
974 if (result._klass->is_objArray_klass()) {
975 result._is_root_segment = _num_obj_arrays_logged++ < _num_root_segments;
976 }
977 _next = _current + result._size * BytesPerWord;
978 return result;
979 }
980
981 AOTMapLogger::OopData obj_at(narrowOop* addr) override {
982 uint64_t n = (uint64_t)(*addr);
983 if (n == 0) {
984 return null_data();
985 } else {
986 precond(n >= _buffer_start_narrow_oop);
987 address buffer_addr = _buffer_start + ((n - _buffer_start_narrow_oop) << _requested_shift);
988 return capture(buffer_addr);
989 }
990 }
991
992 AOTMapLogger::OopData obj_at(oop* addr) override {
993 address requested_value = cast_from_oop<address>(*addr);
994 if (requested_value == nullptr) {
995 return null_data();
996 } else {
997 address buffer_addr = requested_value - _buffer_to_requested_delta;
998 return capture(buffer_addr);
999 }
1000 }
1001
1002 GrowableArrayCHeap<AOTMapLogger::OopData, mtClass>* roots() override {
1003 return new GrowableArrayCHeap<AOTMapLogger::OopData, mtClass>();
1004 }
1005 };
1006
1007 MemRegion r = heap_info->buffer_region();
1008 address buffer_start = address(r.start());
1009 address buffer_end = address(r.end());
1010
1011 address requested_base = UseCompressedOops ? AOTMappedHeapWriter::narrow_oop_base() : (address)AOTMappedHeapWriter::NOCOOPS_REQUESTED_BASE;
1012 address requested_start = UseCompressedOops ? AOTMappedHeapWriter::buffered_addr_to_requested_addr(buffer_start) : requested_base;
1013 int requested_shift = AOTMappedHeapWriter::narrow_oop_shift();
1014 intptr_t buffer_to_requested_delta = requested_start - buffer_start;
1015 uint64_t buffer_start_narrow_oop = 0xdeadbeed;
1016 if (UseCompressedOops) {
1017 buffer_start_narrow_oop = (uint64_t)(pointer_delta(requested_start, requested_base, 1)) >> requested_shift;
1018 assert(buffer_start_narrow_oop < 0xffffffff, "sanity");
1019 }
1020
1021 return new MappedWriterOopIterator(buffer_start,
1022 buffer_end,
1023 buffer_start_narrow_oop,
1024 buffer_to_requested_delta,
1025 requested_shift,
1026 heap_info->root_segments().count());
1027 }
1028
1029 #endif // INCLUDE_CDS_JAVA_HEAP