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/aotReferenceObjSupport.hpp"
26 #include "cds/archiveHeapWriter.hpp"
27 #include "cds/cdsConfig.hpp"
28 #include "cds/filemap.hpp"
29 #include "cds/heapShared.hpp"
30 #include "cds/regeneratedClasses.hpp"
31 #include "classfile/javaClasses.hpp"
32 #include "classfile/modules.hpp"
33 #include "classfile/systemDictionary.hpp"
34 #include "gc/shared/collectedHeap.hpp"
35 #include "memory/iterator.inline.hpp"
36 #include "memory/oopFactory.hpp"
37 #include "memory/universe.hpp"
38 #include "oops/compressedOops.hpp"
39 #include "oops/objArrayOop.inline.hpp"
40 #include "oops/oop.inline.hpp"
41 #include "oops/oopHandle.inline.hpp"
42 #include "oops/typeArrayKlass.hpp"
43 #include "oops/typeArrayOop.hpp"
44 #include "runtime/java.hpp"
45 #include "runtime/mutexLocker.hpp"
46 #include "utilities/bitMap.inline.hpp"
47 #if INCLUDE_G1GC
48 #include "gc/g1/g1CollectedHeap.hpp"
49 #include "gc/g1/g1HeapRegion.hpp"
50 #endif
51
52 #if INCLUDE_CDS_JAVA_HEAP
53
54 GrowableArrayCHeap<u1, mtClassShared>* ArchiveHeapWriter::_buffer = nullptr;
55
56 // The following are offsets from buffer_bottom()
57 size_t ArchiveHeapWriter::_buffer_used;
58
59 // Heap root segments
60 HeapRootSegments ArchiveHeapWriter::_heap_root_segments;
61
62 address ArchiveHeapWriter::_requested_bottom;
63 address ArchiveHeapWriter::_requested_top;
64
65 static size_t _num_strings = 0;
66 static size_t _string_bytes = 0;
67 static size_t _num_packages = 0;
68 static size_t _num_protection_domains = 0;
69
70 GrowableArrayCHeap<ArchiveHeapWriter::NativePointerInfo, mtClassShared>* ArchiveHeapWriter::_native_pointers;
71 GrowableArrayCHeap<oop, mtClassShared>* ArchiveHeapWriter::_source_objs;
72 GrowableArrayCHeap<ArchiveHeapWriter::HeapObjOrder, mtClassShared>* ArchiveHeapWriter::_source_objs_order;
73
74 ArchiveHeapWriter::BufferOffsetToSourceObjectTable*
75 ArchiveHeapWriter::_buffer_offset_to_source_obj_table = nullptr;
76
77
78 typedef ResourceHashtable<
79 size_t, // offset of a filler from ArchiveHeapWriter::buffer_bottom()
80 size_t, // size of this filler (in bytes)
81 127, // prime number
82 AnyObj::C_HEAP,
83 mtClassShared> FillersTable;
84 static FillersTable* _fillers;
85 static int _num_native_ptrs = 0;
86
87 void ArchiveHeapWriter::init() {
88 if (CDSConfig::is_dumping_heap()) {
89 Universe::heap()->collect(GCCause::_java_lang_system_gc);
90
91 _buffer_offset_to_source_obj_table = new BufferOffsetToSourceObjectTable(/*size (prime)*/36137, /*max size*/1 * M);
92 _fillers = new FillersTable();
93 _requested_bottom = nullptr;
94 _requested_top = nullptr;
95
96 _native_pointers = new GrowableArrayCHeap<NativePointerInfo, mtClassShared>(2048);
97 _source_objs = new GrowableArrayCHeap<oop, mtClassShared>(10000);
98
99 guarantee(MIN_GC_REGION_ALIGNMENT <= G1HeapRegion::min_region_size_in_words() * HeapWordSize, "must be");
100 }
101 }
102
103 void ArchiveHeapWriter::delete_tables_with_raw_oops() {
104 delete _source_objs;
105 _source_objs = nullptr;
106 }
107
108 void ArchiveHeapWriter::add_source_obj(oop src_obj) {
109 _source_objs->append(src_obj);
110 }
111
112 void ArchiveHeapWriter::write(GrowableArrayCHeap<oop, mtClassShared>* roots,
113 ArchiveHeapInfo* heap_info) {
114 assert(CDSConfig::is_dumping_heap(), "sanity");
115 allocate_buffer();
116 copy_source_objs_to_buffer(roots);
117 set_requested_address(heap_info);
118 relocate_embedded_oops(roots, heap_info);
119 }
120
121 bool ArchiveHeapWriter::is_too_large_to_archive(oop o) {
122 return is_too_large_to_archive(o->size());
123 }
124
125 bool ArchiveHeapWriter::is_string_too_large_to_archive(oop string) {
126 typeArrayOop value = java_lang_String::value_no_keepalive(string);
127 return is_too_large_to_archive(value);
128 }
129
130 bool ArchiveHeapWriter::is_too_large_to_archive(size_t size) {
131 assert(size > 0, "no zero-size object");
132 assert(size * HeapWordSize > size, "no overflow");
133 static_assert(MIN_GC_REGION_ALIGNMENT > 0, "must be positive");
134
135 size_t byte_size = size * HeapWordSize;
136 if (byte_size > size_t(MIN_GC_REGION_ALIGNMENT)) {
137 return true;
138 } else {
139 return false;
140 }
141 }
142
143 // Various lookup functions between source_obj, buffered_obj and requested_obj
144 bool ArchiveHeapWriter::is_in_requested_range(oop o) {
145 assert(_requested_bottom != nullptr, "do not call before _requested_bottom is initialized");
146 address a = cast_from_oop<address>(o);
147 return (_requested_bottom <= a && a < _requested_top);
148 }
149
150 oop ArchiveHeapWriter::requested_obj_from_buffer_offset(size_t offset) {
151 oop req_obj = cast_to_oop(_requested_bottom + offset);
152 assert(is_in_requested_range(req_obj), "must be");
153 return req_obj;
154 }
155
156 oop ArchiveHeapWriter::source_obj_to_requested_obj(oop src_obj) {
157 assert(CDSConfig::is_dumping_heap(), "dump-time only");
158 HeapShared::CachedOopInfo* p = HeapShared::get_cached_oop_info(src_obj);
159 if (p != nullptr) {
160 return requested_obj_from_buffer_offset(p->buffer_offset());
161 } else {
162 return nullptr;
163 }
164 }
165
166 oop ArchiveHeapWriter::buffered_addr_to_source_obj(address buffered_addr) {
167 OopHandle* oh = _buffer_offset_to_source_obj_table->get(buffered_address_to_offset(buffered_addr));
168 if (oh != nullptr) {
169 return oh->resolve();
170 } else {
171 return nullptr;
172 }
173 }
174
175 address ArchiveHeapWriter::buffered_addr_to_requested_addr(address buffered_addr) {
176 return _requested_bottom + buffered_address_to_offset(buffered_addr);
177 }
178
179 address ArchiveHeapWriter::requested_address() {
180 assert(_buffer != nullptr, "must be initialized");
181 return _requested_bottom;
182 }
183
184 void ArchiveHeapWriter::allocate_buffer() {
185 int initial_buffer_size = 100000;
186 _buffer = new GrowableArrayCHeap<u1, mtClassShared>(initial_buffer_size);
187 _buffer_used = 0;
188 ensure_buffer_space(1); // so that buffer_bottom() works
189 }
190
191 void ArchiveHeapWriter::ensure_buffer_space(size_t min_bytes) {
192 // We usually have very small heaps. If we get a huge one it's probably caused by a bug.
193 guarantee(min_bytes <= max_jint, "we dont support archiving more than 2G of objects");
194 _buffer->at_grow(to_array_index(min_bytes));
195 }
196
197 objArrayOop ArchiveHeapWriter::allocate_root_segment(size_t offset, int element_count) {
198 HeapWord* mem = offset_to_buffered_address<HeapWord *>(offset);
199 memset(mem, 0, objArrayOopDesc::object_size(element_count));
200
201 // The initialization code is copied from MemAllocator::finish and ObjArrayAllocator::initialize.
202 if (UseCompactObjectHeaders) {
203 oopDesc::release_set_mark(mem, Universe::objectArrayKlass()->prototype_header());
204 } else {
205 oopDesc::set_mark(mem, markWord::prototype());
206 oopDesc::release_set_klass(mem, Universe::objectArrayKlass());
207 }
208 arrayOopDesc::set_length(mem, element_count);
209 return objArrayOop(cast_to_oop(mem));
210 }
211
212 void ArchiveHeapWriter::root_segment_at_put(objArrayOop segment, int index, oop root) {
213 // Do not use arrayOop->obj_at_put(i, o) as arrayOop is outside the real heap!
214 if (UseCompressedOops) {
215 *segment->obj_at_addr<narrowOop>(index) = CompressedOops::encode(root);
216 } else {
217 *segment->obj_at_addr<oop>(index) = root;
218 }
219 }
220
221 void ArchiveHeapWriter::copy_roots_to_buffer(GrowableArrayCHeap<oop, mtClassShared>* roots) {
222 // Depending on the number of classes we are archiving, a single roots array may be
223 // larger than MIN_GC_REGION_ALIGNMENT. Roots are allocated first in the buffer, which
224 // allows us to chop the large array into a series of "segments". Current layout
225 // starts with zero or more segments exactly fitting MIN_GC_REGION_ALIGNMENT, and end
226 // with a single segment that may be smaller than MIN_GC_REGION_ALIGNMENT.
227 // This is simple and efficient. We do not need filler objects anywhere between the segments,
228 // or immediately after the last segment. This allows starting the object dump immediately
229 // after the roots.
230
231 assert((_buffer_used % MIN_GC_REGION_ALIGNMENT) == 0,
232 "Pre-condition: Roots start at aligned boundary: %zu", _buffer_used);
233
234 int max_elem_count = ((MIN_GC_REGION_ALIGNMENT - arrayOopDesc::header_size_in_bytes()) / heapOopSize);
235 assert(objArrayOopDesc::object_size(max_elem_count)*HeapWordSize == MIN_GC_REGION_ALIGNMENT,
236 "Should match exactly");
237
238 HeapRootSegments segments(_buffer_used,
239 roots->length(),
240 MIN_GC_REGION_ALIGNMENT,
241 max_elem_count);
242
243 int root_index = 0;
244 for (size_t seg_idx = 0; seg_idx < segments.count(); seg_idx++) {
245 int size_elems = segments.size_in_elems(seg_idx);
246 size_t size_bytes = segments.size_in_bytes(seg_idx);
247
248 size_t oop_offset = _buffer_used;
249 _buffer_used = oop_offset + size_bytes;
250 ensure_buffer_space(_buffer_used);
251
252 assert((oop_offset % MIN_GC_REGION_ALIGNMENT) == 0,
253 "Roots segment %zu start is not aligned: %zu",
254 segments.count(), oop_offset);
255
256 objArrayOop seg_oop = allocate_root_segment(oop_offset, size_elems);
257 for (int i = 0; i < size_elems; i++) {
258 root_segment_at_put(seg_oop, i, roots->at(root_index++));
259 }
260
261 log_info(aot, heap)("archived obj root segment [%d] = %zu bytes, obj = " PTR_FORMAT,
262 size_elems, size_bytes, p2i(seg_oop));
263 }
264
265 assert(root_index == roots->length(), "Post-condition: All roots are handled");
266
267 _heap_root_segments = segments;
268 }
269
270 // The goal is to sort the objects in increasing order of:
271 // - objects that have only oop pointers
272 // - objects that have both native and oop pointers
273 // - objects that have only native pointers
274 // - objects that have no pointers
275 static int oop_sorting_rank(oop o) {
276 bool has_oop_ptr, has_native_ptr;
277 HeapShared::get_pointer_info(o, has_oop_ptr, has_native_ptr);
278
279 if (has_oop_ptr) {
280 if (!has_native_ptr) {
281 return 0;
282 } else {
283 return 1;
284 }
285 } else {
286 if (has_native_ptr) {
287 return 2;
288 } else {
289 return 3;
290 }
291 }
292 }
293
294 int ArchiveHeapWriter::compare_objs_by_oop_fields(HeapObjOrder* a, HeapObjOrder* b) {
295 int rank_a = a->_rank;
296 int rank_b = b->_rank;
297
298 if (rank_a != rank_b) {
299 return rank_a - rank_b;
300 } else {
301 // If they are the same rank, sort them by their position in the _source_objs array
302 return a->_index - b->_index;
303 }
304 }
305
306 void ArchiveHeapWriter::sort_source_objs() {
307 log_info(aot)("sorting heap objects");
308 int len = _source_objs->length();
309 _source_objs_order = new GrowableArrayCHeap<HeapObjOrder, mtClassShared>(len);
310
311 for (int i = 0; i < len; i++) {
312 oop o = _source_objs->at(i);
313 int rank = oop_sorting_rank(o);
314 HeapObjOrder os = {i, rank};
315 _source_objs_order->append(os);
316 }
317 log_info(aot)("computed ranks");
318 _source_objs_order->sort(compare_objs_by_oop_fields);
319 log_info(aot)("sorting heap objects done");
320 }
321
322 void ArchiveHeapWriter::copy_source_objs_to_buffer(GrowableArrayCHeap<oop, mtClassShared>* roots) {
323 // There could be multiple root segments, which we want to be aligned by region.
324 // Putting them ahead of objects makes sure we waste no space.
325 copy_roots_to_buffer(roots);
326
327 sort_source_objs();
328 for (int i = 0; i < _source_objs_order->length(); i++) {
329 int src_obj_index = _source_objs_order->at(i)._index;
330 oop src_obj = _source_objs->at(src_obj_index);
331 HeapShared::CachedOopInfo* info = HeapShared::get_cached_oop_info(src_obj);
332 assert(info != nullptr, "must be");
333 size_t buffer_offset = copy_one_source_obj_to_buffer(src_obj);
334 info->set_buffer_offset(buffer_offset);
335 assert(buffer_offset <= 0x7fffffff, "sanity");
336 HeapShared::add_to_permanent_oop_table(src_obj, (int)buffer_offset);
337
338 OopHandle handle(Universe::vm_global(), src_obj);
339 _buffer_offset_to_source_obj_table->put_when_absent(buffer_offset, handle);
340 _buffer_offset_to_source_obj_table->maybe_grow();
341
342 if (java_lang_Module::is_instance(src_obj)) {
343 Modules::check_archived_module_oop(src_obj);
344 }
345 }
346
347 log_info(aot)("Size of heap region = %zu bytes, %d objects, %d roots, %d native ptrs",
348 _buffer_used, _source_objs->length() + 1, roots->length(), _num_native_ptrs);
349 log_info(cds)(" strings = %8zu (%zu bytes)", _num_strings, _string_bytes);
350 log_info(cds)(" packages = %8zu", _num_packages);
351 log_info(cds)(" protection domains = %8zu", _num_protection_domains);
352 }
353
354 size_t ArchiveHeapWriter::filler_array_byte_size(int length) {
355 size_t byte_size = objArrayOopDesc::object_size(length) * HeapWordSize;
356 return byte_size;
357 }
358
359 int ArchiveHeapWriter::filler_array_length(size_t fill_bytes) {
360 assert(is_object_aligned(fill_bytes), "must be");
361 size_t elemSize = (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop));
362
363 int initial_length = to_array_length(fill_bytes / elemSize);
364 for (int length = initial_length; length >= 0; length --) {
365 size_t array_byte_size = filler_array_byte_size(length);
366 if (array_byte_size == fill_bytes) {
367 return length;
368 }
369 }
370
371 ShouldNotReachHere();
372 return -1;
373 }
374
375 HeapWord* ArchiveHeapWriter::init_filler_array_at_buffer_top(int array_length, size_t fill_bytes) {
376 assert(UseCompressedClassPointers, "Archived heap only supported for compressed klasses");
377 Klass* oak = Universe::objectArrayKlass(); // already relocated to point to archived klass
378 HeapWord* mem = offset_to_buffered_address<HeapWord*>(_buffer_used);
379 memset(mem, 0, fill_bytes);
380 narrowKlass nk = ArchiveBuilder::current()->get_requested_narrow_klass(oak);
381 if (UseCompactObjectHeaders) {
382 oopDesc::release_set_mark(mem, markWord::prototype().set_narrow_klass(nk));
383 } else {
384 oopDesc::set_mark(mem, markWord::prototype());
385 cast_to_oop(mem)->set_narrow_klass(nk);
386 }
387 arrayOopDesc::set_length(mem, array_length);
388 return mem;
389 }
390
391 void ArchiveHeapWriter::maybe_fill_gc_region_gap(size_t required_byte_size) {
392 // We fill only with arrays (so we don't need to use a single HeapWord filler if the
393 // leftover space is smaller than a zero-sized array object). Therefore, we need to
394 // make sure there's enough space of min_filler_byte_size in the current region after
395 // required_byte_size has been allocated. If not, fill the remainder of the current
396 // region.
397 size_t min_filler_byte_size = filler_array_byte_size(0);
398 size_t new_used = _buffer_used + required_byte_size + min_filler_byte_size;
399
400 const size_t cur_min_region_bottom = align_down(_buffer_used, MIN_GC_REGION_ALIGNMENT);
401 const size_t next_min_region_bottom = align_down(new_used, MIN_GC_REGION_ALIGNMENT);
402
403 if (cur_min_region_bottom != next_min_region_bottom) {
404 // Make sure that no objects span across MIN_GC_REGION_ALIGNMENT. This way
405 // we can map the region in any region-based collector.
406 assert(next_min_region_bottom > cur_min_region_bottom, "must be");
407 assert(next_min_region_bottom - cur_min_region_bottom == MIN_GC_REGION_ALIGNMENT,
408 "no buffered object can be larger than %d bytes", MIN_GC_REGION_ALIGNMENT);
409
410 const size_t filler_end = next_min_region_bottom;
411 const size_t fill_bytes = filler_end - _buffer_used;
412 assert(fill_bytes > 0, "must be");
413 ensure_buffer_space(filler_end);
414
415 int array_length = filler_array_length(fill_bytes);
416 log_info(aot, heap)("Inserting filler obj array of %d elements (%zu bytes total) @ buffer offset %zu",
417 array_length, fill_bytes, _buffer_used);
418 HeapWord* filler = init_filler_array_at_buffer_top(array_length, fill_bytes);
419 _buffer_used = filler_end;
420 _fillers->put(buffered_address_to_offset((address)filler), fill_bytes);
421 }
422 }
423
424 size_t ArchiveHeapWriter::get_filler_size_at(address buffered_addr) {
425 size_t* p = _fillers->get(buffered_address_to_offset(buffered_addr));
426 if (p != nullptr) {
427 assert(*p > 0, "filler must be larger than zero bytes");
428 return *p;
429 } else {
430 return 0; // buffered_addr is not a filler
431 }
432 }
433
434 template <typename T>
435 void update_buffered_object_field(address buffered_obj, int field_offset, T value) {
436 T* field_addr = cast_to_oop(buffered_obj)->field_addr<T>(field_offset);
437 *field_addr = value;
438 }
439
440 void ArchiveHeapWriter::update_stats(oop src_obj) {
441 if (java_lang_String::is_instance(src_obj)) {
442 _num_strings ++;
443 _string_bytes += src_obj->size() * HeapWordSize;
444 _string_bytes += java_lang_String::value(src_obj)->size() * HeapWordSize;
445 } else {
446 Klass* k = src_obj->klass();
447 Symbol* name = k->name();
448 if (name->equals("java/lang/NamedPackage") || name->equals("java/lang/Package")) {
449 _num_packages ++;
450 } else if (name->equals("java/security/ProtectionDomain")) {
451 _num_protection_domains ++;
452 }
453 }
454 }
455
456 size_t ArchiveHeapWriter::copy_one_source_obj_to_buffer(oop src_obj) {
457 update_stats(src_obj);
458
459 assert(!is_too_large_to_archive(src_obj), "already checked");
460 size_t byte_size = src_obj->size() * HeapWordSize;
461 assert(byte_size > 0, "no zero-size objects");
462
463 // For region-based collectors such as G1, the archive heap may be mapped into
464 // multiple regions. We need to make sure that we don't have an object that can possible
465 // span across two regions.
466 maybe_fill_gc_region_gap(byte_size);
467
468 size_t new_used = _buffer_used + byte_size;
469 assert(new_used > _buffer_used, "no wrap around");
470
471 size_t cur_min_region_bottom = align_down(_buffer_used, MIN_GC_REGION_ALIGNMENT);
472 size_t next_min_region_bottom = align_down(new_used, MIN_GC_REGION_ALIGNMENT);
473 assert(cur_min_region_bottom == next_min_region_bottom, "no object should cross minimal GC region boundaries");
474
475 ensure_buffer_space(new_used);
476
477 address from = cast_from_oop<address>(src_obj);
478 address to = offset_to_buffered_address<address>(_buffer_used);
479 assert(is_object_aligned(_buffer_used), "sanity");
480 assert(is_object_aligned(byte_size), "sanity");
481 memcpy(to, from, byte_size);
482
483 // These native pointers will be restored explicitly at run time.
484 if (java_lang_Module::is_instance(src_obj)) {
485 update_buffered_object_field<ModuleEntry*>(to, java_lang_Module::module_entry_offset(), nullptr);
486 } else if (java_lang_ClassLoader::is_instance(src_obj)) {
487 #ifdef ASSERT
488 // We only archive these loaders
489 if (src_obj != SystemDictionary::java_platform_loader() &&
490 src_obj != SystemDictionary::java_system_loader()) {
491 assert(src_obj->klass()->name()->equals("jdk/internal/loader/ClassLoaders$BootClassLoader"), "must be");
492 }
493 #endif
494 update_buffered_object_field<ClassLoaderData*>(to, java_lang_ClassLoader::loader_data_offset(), nullptr);
495 }
496
497 size_t buffered_obj_offset = _buffer_used;
498 _buffer_used = new_used;
499
500 return buffered_obj_offset;
501 }
502
503 void ArchiveHeapWriter::set_requested_address(ArchiveHeapInfo* info) {
504 assert(!info->is_used(), "only set once");
505
506 size_t heap_region_byte_size = _buffer_used;
507 assert(heap_region_byte_size > 0, "must archived at least one object!");
508
509 if (UseCompressedOops) {
510 if (UseG1GC) {
511 address heap_end = (address)G1CollectedHeap::heap()->reserved().end();
512 log_info(aot, heap)("Heap end = %p", heap_end);
513 _requested_bottom = align_down(heap_end - heap_region_byte_size, G1HeapRegion::GrainBytes);
514 _requested_bottom = align_down(_requested_bottom, MIN_GC_REGION_ALIGNMENT);
515 assert(is_aligned(_requested_bottom, G1HeapRegion::GrainBytes), "sanity");
516 } else {
517 _requested_bottom = align_up(CompressedOops::begin(), MIN_GC_REGION_ALIGNMENT);
518 }
519 } else {
520 // We always write the objects as if the heap started at this address. This
521 // makes the contents of the archive heap deterministic.
522 //
523 // Note that at runtime, the heap address is selected by the OS, so the archive
524 // heap will not be mapped at 0x10000000, and the contents need to be patched.
525 _requested_bottom = align_up((address)NOCOOPS_REQUESTED_BASE, MIN_GC_REGION_ALIGNMENT);
526 }
527
528 assert(is_aligned(_requested_bottom, MIN_GC_REGION_ALIGNMENT), "sanity");
529
530 _requested_top = _requested_bottom + _buffer_used;
531
532 info->set_buffer_region(MemRegion(offset_to_buffered_address<HeapWord*>(0),
533 offset_to_buffered_address<HeapWord*>(_buffer_used)));
534 info->set_heap_root_segments(_heap_root_segments);
535 }
536
537 // Oop relocation
538
539 template <typename T> T* ArchiveHeapWriter::requested_addr_to_buffered_addr(T* p) {
540 assert(is_in_requested_range(cast_to_oop(p)), "must be");
541
542 address addr = address(p);
543 assert(addr >= _requested_bottom, "must be");
544 size_t offset = addr - _requested_bottom;
545 return offset_to_buffered_address<T*>(offset);
546 }
547
548 template <typename T> oop ArchiveHeapWriter::load_source_oop_from_buffer(T* buffered_addr) {
549 oop o = load_oop_from_buffer(buffered_addr);
550 assert(!in_buffer(cast_from_oop<address>(o)), "must point to source oop");
551 return o;
552 }
553
554 template <typename T> void ArchiveHeapWriter::store_requested_oop_in_buffer(T* buffered_addr,
555 oop request_oop) {
556 assert(is_in_requested_range(request_oop), "must be");
557 store_oop_in_buffer(buffered_addr, request_oop);
558 }
559
560 inline void ArchiveHeapWriter::store_oop_in_buffer(oop* buffered_addr, oop requested_obj) {
561 *buffered_addr = requested_obj;
562 }
563
564 inline void ArchiveHeapWriter::store_oop_in_buffer(narrowOop* buffered_addr, oop requested_obj) {
565 narrowOop val = CompressedOops::encode_not_null(requested_obj);
566 *buffered_addr = val;
567 }
568
569 oop ArchiveHeapWriter::load_oop_from_buffer(oop* buffered_addr) {
570 return *buffered_addr;
571 }
572
573 oop ArchiveHeapWriter::load_oop_from_buffer(narrowOop* buffered_addr) {
574 return CompressedOops::decode(*buffered_addr);
575 }
576
577 template <typename T> void ArchiveHeapWriter::relocate_field_in_buffer(T* field_addr_in_buffer, CHeapBitMap* oopmap) {
578 oop source_referent = load_source_oop_from_buffer<T>(field_addr_in_buffer);
579 if (source_referent != nullptr) {
580 if (java_lang_Class::is_instance(source_referent)) {
581 // When the source object points to a "real" mirror, the buffered object should point
582 // to the "scratch" mirror, which has all unarchivable fields scrubbed (to be reinstated
583 // at run time).
584 source_referent = HeapShared::scratch_java_mirror(source_referent);
585 assert(source_referent != nullptr, "must be");
586 }
587 oop request_referent = source_obj_to_requested_obj(source_referent);
588 store_requested_oop_in_buffer<T>(field_addr_in_buffer, request_referent);
589 mark_oop_pointer<T>(field_addr_in_buffer, oopmap);
590 }
591 }
592
593 template <typename T> void ArchiveHeapWriter::mark_oop_pointer(T* buffered_addr, CHeapBitMap* oopmap) {
594 T* request_p = (T*)(buffered_addr_to_requested_addr((address)buffered_addr));
595 address requested_region_bottom;
596
597 assert(request_p >= (T*)_requested_bottom, "sanity");
598 assert(request_p < (T*)_requested_top, "sanity");
599 requested_region_bottom = _requested_bottom;
600
601 // Mark the pointer in the oopmap
602 T* region_bottom = (T*)requested_region_bottom;
603 assert(request_p >= region_bottom, "must be");
604 BitMap::idx_t idx = request_p - region_bottom;
605 assert(idx < oopmap->size(), "overflow");
606 oopmap->set_bit(idx);
607 }
608
609 void ArchiveHeapWriter::update_header_for_requested_obj(oop requested_obj, oop src_obj, Klass* src_klass) {
610 assert(UseCompressedClassPointers, "Archived heap only supported for compressed klasses");
611 narrowKlass nk = ArchiveBuilder::current()->get_requested_narrow_klass(src_klass);
612 address buffered_addr = requested_addr_to_buffered_addr(cast_from_oop<address>(requested_obj));
613
614 oop fake_oop = cast_to_oop(buffered_addr);
615 if (UseCompactObjectHeaders) {
616 fake_oop->set_mark(markWord::prototype().set_narrow_klass(nk));
617 } else {
618 fake_oop->set_narrow_klass(nk);
619 }
620
621 if (src_obj == nullptr) {
622 return;
623 }
624 // We need to retain the identity_hash, because it may have been used by some hashtables
625 // in the shared heap.
626 if (!src_obj->fast_no_hash_check()) {
627 intptr_t src_hash = src_obj->identity_hash();
628 if (UseCompactObjectHeaders) {
629 fake_oop->set_mark(markWord::prototype().set_narrow_klass(nk).copy_set_hash(src_hash));
630 } else {
631 fake_oop->set_mark(markWord::prototype().copy_set_hash(src_hash));
632 }
633 assert(fake_oop->mark().is_unlocked(), "sanity");
634
635 DEBUG_ONLY(intptr_t archived_hash = fake_oop->identity_hash());
636 assert(src_hash == archived_hash, "Different hash codes: original " INTPTR_FORMAT ", archived " INTPTR_FORMAT, src_hash, archived_hash);
637 }
638 // Strip age bits.
639 fake_oop->set_mark(fake_oop->mark().set_age(0));
640 }
641
642 class ArchiveHeapWriter::EmbeddedOopRelocator: public BasicOopIterateClosure {
643 oop _src_obj;
644 address _buffered_obj;
645 CHeapBitMap* _oopmap;
646 bool _is_java_lang_ref;
647 public:
648 EmbeddedOopRelocator(oop src_obj, address buffered_obj, CHeapBitMap* oopmap) :
649 _src_obj(src_obj), _buffered_obj(buffered_obj), _oopmap(oopmap)
650 {
651 _is_java_lang_ref = AOTReferenceObjSupport::check_if_ref_obj(src_obj);
652 }
653
654 void do_oop(narrowOop *p) { EmbeddedOopRelocator::do_oop_work(p); }
655 void do_oop( oop *p) { EmbeddedOopRelocator::do_oop_work(p); }
656
657 private:
658 template <class T> void do_oop_work(T *p) {
659 int field_offset = pointer_delta_as_int((char*)p, cast_from_oop<char*>(_src_obj));
660 T* field_addr = (T*)(_buffered_obj + field_offset);
661 if (_is_java_lang_ref && AOTReferenceObjSupport::skip_field(field_offset)) {
662 // Do not copy these fields. Set them to null
663 *field_addr = (T)0x0;
664 } else {
665 ArchiveHeapWriter::relocate_field_in_buffer<T>(field_addr, _oopmap);
666 }
667 }
668 };
669
670 static void log_bitmap_usage(const char* which, BitMap* bitmap, size_t total_bits) {
671 // The whole heap is covered by total_bits, but there are only non-zero bits within [start ... end).
672 size_t start = bitmap->find_first_set_bit(0);
673 size_t end = bitmap->size();
674 log_info(aot)("%s = %7zu ... %7zu (%3zu%% ... %3zu%% = %3zu%%)", which,
675 start, end,
676 start * 100 / total_bits,
677 end * 100 / total_bits,
678 (end - start) * 100 / total_bits);
679 }
680
681 // Update all oop fields embedded in the buffered objects
682 void ArchiveHeapWriter::relocate_embedded_oops(GrowableArrayCHeap<oop, mtClassShared>* roots,
683 ArchiveHeapInfo* heap_info) {
684 size_t oopmap_unit = (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop));
685 size_t heap_region_byte_size = _buffer_used;
686 heap_info->oopmap()->resize(heap_region_byte_size / oopmap_unit);
687
688 for (int i = 0; i < _source_objs_order->length(); i++) {
689 int src_obj_index = _source_objs_order->at(i)._index;
690 oop src_obj = _source_objs->at(src_obj_index);
691 HeapShared::CachedOopInfo* info = HeapShared::get_cached_oop_info(src_obj);
692 assert(info != nullptr, "must be");
693 oop requested_obj = requested_obj_from_buffer_offset(info->buffer_offset());
694 update_header_for_requested_obj(requested_obj, src_obj, src_obj->klass());
695 address buffered_obj = offset_to_buffered_address<address>(info->buffer_offset());
696 EmbeddedOopRelocator relocator(src_obj, buffered_obj, heap_info->oopmap());
697 src_obj->oop_iterate(&relocator);
698 };
699
700 // Relocate HeapShared::roots(), which is created in copy_roots_to_buffer() and
701 // doesn't have a corresponding src_obj, so we can't use EmbeddedOopRelocator on it.
702 for (size_t seg_idx = 0; seg_idx < _heap_root_segments.count(); seg_idx++) {
703 size_t seg_offset = _heap_root_segments.segment_offset(seg_idx);
704
705 objArrayOop requested_obj = (objArrayOop)requested_obj_from_buffer_offset(seg_offset);
706 update_header_for_requested_obj(requested_obj, nullptr, Universe::objectArrayKlass());
707 address buffered_obj = offset_to_buffered_address<address>(seg_offset);
708 int length = _heap_root_segments.size_in_elems(seg_idx);
709
710 if (UseCompressedOops) {
711 for (int i = 0; i < length; i++) {
712 narrowOop* addr = (narrowOop*)(buffered_obj + objArrayOopDesc::obj_at_offset<narrowOop>(i));
713 relocate_field_in_buffer<narrowOop>(addr, heap_info->oopmap());
714 }
715 } else {
716 for (int i = 0; i < length; i++) {
717 oop* addr = (oop*)(buffered_obj + objArrayOopDesc::obj_at_offset<oop>(i));
718 relocate_field_in_buffer<oop>(addr, heap_info->oopmap());
719 }
720 }
721 }
722
723 compute_ptrmap(heap_info);
724
725 size_t total_bytes = (size_t)_buffer->length();
726 log_bitmap_usage("oopmap", heap_info->oopmap(), total_bytes / (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop)));
727 log_bitmap_usage("ptrmap", heap_info->ptrmap(), total_bytes / sizeof(address));
728 }
729
730 void ArchiveHeapWriter::mark_native_pointer(oop src_obj, int field_offset) {
731 Metadata* ptr = src_obj->metadata_field_acquire(field_offset);
732 if (ptr != nullptr) {
733 NativePointerInfo info;
734 info._src_obj = src_obj;
735 info._field_offset = field_offset;
736 _native_pointers->append(info);
737 HeapShared::set_has_native_pointers(src_obj);
738 _num_native_ptrs ++;
739 }
740 }
741
742 // Do we have a jlong/jint field that's actually a pointer to a MetaspaceObj?
743 bool ArchiveHeapWriter::is_marked_as_native_pointer(ArchiveHeapInfo* heap_info, address buffered_obj, int field_offset) {
744 size_t offset = buffered_address_to_offset(buffered_obj) + checked_cast<size_t>(field_offset); // in bytes
745 BitMap::idx_t idx = checked_cast<BitMap::idx_t>(offset) / HeapWordSize;
746 // Leading zeros have been removed so some addresses may not be in the ptrmap
747 size_t start_pos = FileMapInfo::current_info()->heap_ptrmap_start_pos();
748 if (idx < start_pos) {
749 return false;
750 } else {
751 idx -= start_pos;
752 }
753 return (idx < heap_info->ptrmap()->size()) && (heap_info->ptrmap()->at(idx) == true);
754 }
755
756 void ArchiveHeapWriter::compute_ptrmap(ArchiveHeapInfo* heap_info) {
757 int num_non_null_ptrs = 0;
758 Metadata** bottom = (Metadata**) _requested_bottom;
759 Metadata** top = (Metadata**) _requested_top; // exclusive
760 heap_info->ptrmap()->resize(top - bottom);
761
762 BitMap::idx_t max_idx = 32; // paranoid - don't make it too small
763 for (int i = 0; i < _native_pointers->length(); i++) {
764 NativePointerInfo info = _native_pointers->at(i);
765 oop src_obj = info._src_obj;
766 int field_offset = info._field_offset;
767 HeapShared::CachedOopInfo* p = HeapShared::get_cached_oop_info(src_obj);
768 // requested_field_addr = the address of this field in the requested space
769 oop requested_obj = requested_obj_from_buffer_offset(p->buffer_offset());
770 Metadata** requested_field_addr = (Metadata**)(cast_from_oop<address>(requested_obj) + field_offset);
771 assert(bottom <= requested_field_addr && requested_field_addr < top, "range check");
772
773 // Mark this field in the bitmap
774 BitMap::idx_t idx = requested_field_addr - bottom;
775 heap_info->ptrmap()->set_bit(idx);
776 num_non_null_ptrs ++;
777 max_idx = MAX2(max_idx, idx);
778
779 // Set the native pointer to the requested address of the metadata (at runtime, the metadata will have
780 // this address if the RO/RW regions are mapped at the default location).
781
782 Metadata** buffered_field_addr = requested_addr_to_buffered_addr(requested_field_addr);
783 Metadata* native_ptr = *buffered_field_addr;
784 guarantee(native_ptr != nullptr, "sanity");
785 guarantee(ArchiveBuilder::current()->has_been_buffered((address)native_ptr),
786 "Metadata %p should have been archived", native_ptr);
787
788 if (RegeneratedClasses::has_been_regenerated((address)native_ptr)) {
789 native_ptr = (Metadata*)RegeneratedClasses::get_regenerated_object((address)native_ptr);
790 }
791
792 address buffered_native_ptr = ArchiveBuilder::current()->get_buffered_addr((address)native_ptr);
793 address requested_native_ptr = ArchiveBuilder::current()->to_requested(buffered_native_ptr);
794 *buffered_field_addr = (Metadata*)requested_native_ptr;
795 }
796
797 heap_info->ptrmap()->resize(max_idx + 1);
798 log_info(aot, heap)("calculate_ptrmap: marked %d non-null native pointers for heap region (%zu bits)",
799 num_non_null_ptrs, size_t(heap_info->ptrmap()->size()));
800 }
801
802 #endif // INCLUDE_CDS_JAVA_HEAP