1 /*
2 * Copyright (c) 2024, 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 "precompiled.hpp"
26 #include "cds/archiveHeapWriter.hpp"
27 #include "cds/cdsConfig.hpp"
28 #include "cds/filemap.hpp"
29 #include "cds/heapShared.hpp"
30 #include "classfile/systemDictionary.hpp"
31 #include "gc/shared/collectedHeap.hpp"
32 #include "memory/iterator.inline.hpp"
33 #include "memory/oopFactory.hpp"
34 #include "memory/universe.hpp"
35 #include "oops/compressedOops.hpp"
36 #include "oops/oop.inline.hpp"
37 #include "oops/objArrayOop.inline.hpp"
38 #include "oops/oopHandle.inline.hpp"
39 #include "oops/typeArrayKlass.hpp"
40 #include "oops/typeArrayOop.hpp"
41 #include "runtime/java.hpp"
42 #include "runtime/mutexLocker.hpp"
43 #include "utilities/bitMap.inline.hpp"
44 #if INCLUDE_G1GC
45 #include "gc/g1/g1CollectedHeap.hpp"
46 #include "gc/g1/g1HeapRegion.hpp"
47 #endif
48
49 #if INCLUDE_CDS_JAVA_HEAP
50
51 GrowableArrayCHeap<u1, mtClassShared>* ArchiveHeapWriter::_buffer = nullptr;
52
53 // The following are offsets from buffer_bottom()
54 size_t ArchiveHeapWriter::_buffer_used;
55 size_t ArchiveHeapWriter::_heap_roots_offset;
56
57 size_t ArchiveHeapWriter::_heap_roots_word_size;
58
59 address ArchiveHeapWriter::_requested_bottom;
60 address ArchiveHeapWriter::_requested_top;
61
62 GrowableArrayCHeap<ArchiveHeapWriter::NativePointerInfo, mtClassShared>* ArchiveHeapWriter::_native_pointers;
63 GrowableArrayCHeap<oop, mtClassShared>* ArchiveHeapWriter::_source_objs;
64 GrowableArrayCHeap<ArchiveHeapWriter::HeapObjOrder, mtClassShared>* ArchiveHeapWriter::_source_objs_order;
65
66 ArchiveHeapWriter::BufferOffsetToSourceObjectTable*
67 ArchiveHeapWriter::_buffer_offset_to_source_obj_table = nullptr;
68
69
70 typedef ResourceHashtable<address, size_t,
71 127, // prime number
72 AnyObj::C_HEAP,
73 mtClassShared> FillersTable;
74 static FillersTable* _fillers;
75 static int _num_native_ptrs = 0;
76
77 void ArchiveHeapWriter::init() {
78 if (HeapShared::can_write()) {
79 Universe::heap()->collect(GCCause::_java_lang_system_gc);
80
81 _buffer_offset_to_source_obj_table = new BufferOffsetToSourceObjectTable(/*size (prime)*/36137, /*max size*/1 * M);
82 _fillers = new FillersTable();
83 _requested_bottom = nullptr;
84 _requested_top = nullptr;
85
86 _native_pointers = new GrowableArrayCHeap<NativePointerInfo, mtClassShared>(2048);
87 _source_objs = new GrowableArrayCHeap<oop, mtClassShared>(10000);
88
89 guarantee(UseG1GC, "implementation limitation");
90 guarantee(MIN_GC_REGION_ALIGNMENT <= /*G1*/HeapRegion::min_region_size_in_words() * HeapWordSize, "must be");
91 }
92 }
93
94 void ArchiveHeapWriter::add_source_obj(oop src_obj) {
95 _source_objs->append(src_obj);
96 }
97
98 void ArchiveHeapWriter::write(GrowableArrayCHeap<oop, mtClassShared>* roots,
99 ArchiveHeapInfo* heap_info) {
100 assert(HeapShared::can_write(), "sanity");
101 allocate_buffer();
102 copy_source_objs_to_buffer(roots);
103 set_requested_address(heap_info);
104 relocate_embedded_oops(roots, heap_info);
105 }
106
107 bool ArchiveHeapWriter::is_too_large_to_archive(oop o) {
108 return is_too_large_to_archive(o->size());
109 }
110
111 bool ArchiveHeapWriter::is_string_too_large_to_archive(oop string) {
112 typeArrayOop value = java_lang_String::value_no_keepalive(string);
113 return is_too_large_to_archive(value);
114 }
115
116 bool ArchiveHeapWriter::is_too_large_to_archive(size_t size) {
117 assert(size > 0, "no zero-size object");
118 assert(size * HeapWordSize > size, "no overflow");
119 static_assert(MIN_GC_REGION_ALIGNMENT > 0, "must be positive");
120
121 size_t byte_size = size * HeapWordSize;
122 if (byte_size > size_t(MIN_GC_REGION_ALIGNMENT)) {
123 return true;
124 } else {
125 return false;
126 }
127 }
128
129 // Various lookup functions between source_obj, buffered_obj and requested_obj
130 bool ArchiveHeapWriter::is_in_requested_range(oop o) {
131 assert(_requested_bottom != nullptr, "do not call before _requested_bottom is initialized");
132 address a = cast_from_oop<address>(o);
133 return (_requested_bottom <= a && a < _requested_top);
134 }
135
136 oop ArchiveHeapWriter::requested_obj_from_buffer_offset(size_t offset) {
137 oop req_obj = cast_to_oop(_requested_bottom + offset);
138 assert(is_in_requested_range(req_obj), "must be");
139 return req_obj;
140 }
141
142 oop ArchiveHeapWriter::source_obj_to_requested_obj(oop src_obj) {
143 assert(CDSConfig::is_dumping_heap(), "dump-time only");
144 HeapShared::CachedOopInfo* p = HeapShared::archived_object_cache()->get(src_obj);
145 if (p != nullptr) {
146 return requested_obj_from_buffer_offset(p->buffer_offset());
147 } else {
148 return nullptr;
149 }
150 }
151
152 oop ArchiveHeapWriter::buffered_addr_to_source_obj(address buffered_addr) {
153 oop* p = _buffer_offset_to_source_obj_table->get(buffered_address_to_offset(buffered_addr));
154 if (p != nullptr) {
155 return *p;
156 } else {
157 return nullptr;
158 }
159 }
160
161 address ArchiveHeapWriter::buffered_addr_to_requested_addr(address buffered_addr) {
162 return _requested_bottom + buffered_address_to_offset(buffered_addr);
163 }
164
165 oop ArchiveHeapWriter::heap_roots_requested_address() {
166 return cast_to_oop(_requested_bottom + _heap_roots_offset);
167 }
168
169 address ArchiveHeapWriter::requested_address() {
170 assert(_buffer != nullptr, "must be initialized");
171 return _requested_bottom;
172 }
173
174 void ArchiveHeapWriter::allocate_buffer() {
175 int initial_buffer_size = 100000;
176 _buffer = new GrowableArrayCHeap<u1, mtClassShared>(initial_buffer_size);
177 _buffer_used = 0;
178 ensure_buffer_space(1); // so that buffer_bottom() works
179 }
180
181 void ArchiveHeapWriter::ensure_buffer_space(size_t min_bytes) {
182 // We usually have very small heaps. If we get a huge one it's probably caused by a bug.
183 guarantee(min_bytes <= max_jint, "we dont support archiving more than 2G of objects");
184 _buffer->at_grow(to_array_index(min_bytes));
185 }
186
187 void ArchiveHeapWriter::copy_roots_to_buffer(GrowableArrayCHeap<oop, mtClassShared>* roots) {
188 Klass* k = Universe::objectArrayKlass(); // already relocated to point to archived klass
189 int length = roots->length();
190 _heap_roots_word_size = objArrayOopDesc::object_size(length);
191 size_t byte_size = _heap_roots_word_size * HeapWordSize;
192 if (byte_size >= MIN_GC_REGION_ALIGNMENT) {
193 log_error(cds, heap)("roots array is too large. Please reduce the number of classes");
194 vm_exit(1);
195 }
196
197 maybe_fill_gc_region_gap(byte_size);
198
199 size_t new_used = _buffer_used + byte_size;
200 ensure_buffer_space(new_used);
201
202 HeapWord* mem = offset_to_buffered_address<HeapWord*>(_buffer_used);
203 memset(mem, 0, byte_size);
204 {
205 // This is copied from MemAllocator::finish
206 if (UseCompactObjectHeaders) {
207 narrowKlass nk = ArchiveBuilder::current()->get_requested_narrow_klass(k);
208 oopDesc::release_set_mark(mem, markWord::prototype().set_narrow_klass(nk));
209 } else {
210 oopDesc::set_mark(mem, markWord::prototype());
211 oopDesc::release_set_klass(mem, k);
212 }
213 }
214 {
215 // This is copied from ObjArrayAllocator::initialize
216 arrayOopDesc::set_length(mem, length);
217 }
218
219 objArrayOop arrayOop = objArrayOop(cast_to_oop(mem));
220 for (int i = 0; i < length; i++) {
221 // Do not use arrayOop->obj_at_put(i, o) as arrayOop is outside of the real heap!
222 oop o = roots->at(i);
223 if (UseCompressedOops) {
224 * arrayOop->obj_at_addr<narrowOop>(i) = CompressedOops::encode(o);
225 } else {
226 * arrayOop->obj_at_addr<oop>(i) = o;
227 }
228 }
229 log_info(cds, heap)("archived obj roots[%d] = " SIZE_FORMAT " bytes, klass = %p, obj = %p", length, byte_size, k, mem);
230
231 _heap_roots_offset = _buffer_used;
232 _buffer_used = new_used;
233 }
234
235 static int oop_sorting_rank(oop o) {
236 bool has_oop_ptr, has_native_ptr;
237 HeapShared::get_pointer_info(o, has_oop_ptr, has_native_ptr);
238
239 if (!has_oop_ptr) {
240 if (!has_native_ptr) {
241 return 0;
242 } else {
243 return 1;
244 }
245 } else {
246 if (has_native_ptr) {
247 return 2;
248 } else {
249 return 3;
250 }
251 }
252 }
253
254 // The goal is to sort the objects in increasing order of:
255 // - objects that have no pointers
256 // - objects that have only native pointers
257 // - objects that have both native and oop pointers
258 // - objects that have only oop pointers
259 int ArchiveHeapWriter::compare_objs_by_oop_fields(HeapObjOrder* a, HeapObjOrder* b) {
260 int rank_a = a->_rank;
261 int rank_b = b->_rank;
262
263 if (rank_a != rank_b) {
264 return rank_a - rank_b;
265 } else {
266 // If they are the same rank, sort them by their position in the _source_objs array
267 return a->_index - b->_index;
268 }
269 }
270
271 void ArchiveHeapWriter::sort_source_objs() {
272 log_info(cds)("sorting heap objects");
273 int len = _source_objs->length();
274 _source_objs_order = new GrowableArrayCHeap<HeapObjOrder, mtClassShared>(len);
275
276 for (int i = 0; i < len; i++) {
277 oop o = _source_objs->at(i);
278 int rank = oop_sorting_rank(o);
279 HeapObjOrder os = {i, rank};
280 _source_objs_order->append(os);
281 }
282 log_info(cds)("computed ranks");
283 _source_objs_order->sort(compare_objs_by_oop_fields);
284 log_info(cds)("sorting heap objects done");
285 }
286
287 void ArchiveHeapWriter::copy_source_objs_to_buffer(GrowableArrayCHeap<oop, mtClassShared>* roots) {
288 sort_source_objs();
289 for (int i = 0; i < _source_objs_order->length(); i++) {
290 int src_obj_index = _source_objs_order->at(i)._index;
291 oop src_obj = _source_objs->at(src_obj_index);
292 HeapShared::CachedOopInfo* info = HeapShared::archived_object_cache()->get(src_obj);
293 assert(info != nullptr, "must be");
294 size_t buffer_offset = copy_one_source_obj_to_buffer(src_obj);
295 info->set_buffer_offset(buffer_offset);
296
297 _buffer_offset_to_source_obj_table->put_when_absent(buffer_offset, src_obj);
298 _buffer_offset_to_source_obj_table->maybe_grow();
299 }
300
301 copy_roots_to_buffer(roots);
302
303 log_info(cds)("Size of heap region = " SIZE_FORMAT " bytes, %d objects, %d roots, %d native ptrs",
304 _buffer_used, _source_objs->length() + 1, roots->length(), _num_native_ptrs);
305 }
306
307 size_t ArchiveHeapWriter::filler_array_byte_size(int length) {
308 size_t byte_size = objArrayOopDesc::object_size(length) * HeapWordSize;
309 return byte_size;
310 }
311
312 int ArchiveHeapWriter::filler_array_length(size_t fill_bytes) {
313 assert(is_object_aligned(fill_bytes), "must be");
314 size_t elemSize = (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop));
315
316 int initial_length = to_array_length(fill_bytes / elemSize);
317 for (int length = initial_length; length >= 0; length --) {
318 size_t array_byte_size = filler_array_byte_size(length);
319 if (array_byte_size == fill_bytes) {
320 return length;
321 }
322 }
323
324 ShouldNotReachHere();
325 return -1;
326 }
327
328 HeapWord* ArchiveHeapWriter::init_filler_array_at_buffer_top(int array_length, size_t fill_bytes) {
329 assert(UseCompressedClassPointers, "Archived heap only supported for compressed klasses");
330 Klass* oak = Universe::objectArrayKlass(); // already relocated to point to archived klass
331 HeapWord* mem = offset_to_buffered_address<HeapWord*>(_buffer_used);
332 memset(mem, 0, fill_bytes);
333 narrowKlass nk = ArchiveBuilder::current()->get_requested_narrow_klass(oak);
334 if (UseCompactObjectHeaders) {
335 oopDesc::release_set_mark(mem, markWord::prototype().set_narrow_klass(nk));
336 } else {
337 oopDesc::set_mark(mem, markWord::prototype());
338 cast_to_oop(mem)->set_narrow_klass(nk);
339 }
340 arrayOopDesc::set_length(mem, array_length);
341 return mem;
342 }
343
344 void ArchiveHeapWriter::maybe_fill_gc_region_gap(size_t required_byte_size) {
345 // We fill only with arrays (so we don't need to use a single HeapWord filler if the
346 // leftover space is smaller than a zero-sized array object). Therefore, we need to
347 // make sure there's enough space of min_filler_byte_size in the current region after
348 // required_byte_size has been allocated. If not, fill the remainder of the current
349 // region.
350 size_t min_filler_byte_size = filler_array_byte_size(0);
351 size_t new_used = _buffer_used + required_byte_size + min_filler_byte_size;
352
353 const size_t cur_min_region_bottom = align_down(_buffer_used, MIN_GC_REGION_ALIGNMENT);
354 const size_t next_min_region_bottom = align_down(new_used, MIN_GC_REGION_ALIGNMENT);
355
356 if (cur_min_region_bottom != next_min_region_bottom) {
357 // Make sure that no objects span across MIN_GC_REGION_ALIGNMENT. This way
358 // we can map the region in any region-based collector.
359 assert(next_min_region_bottom > cur_min_region_bottom, "must be");
360 assert(next_min_region_bottom - cur_min_region_bottom == MIN_GC_REGION_ALIGNMENT,
361 "no buffered object can be larger than %d bytes", MIN_GC_REGION_ALIGNMENT);
362
363 const size_t filler_end = next_min_region_bottom;
364 const size_t fill_bytes = filler_end - _buffer_used;
365 assert(fill_bytes > 0, "must be");
366 ensure_buffer_space(filler_end);
367
368 int array_length = filler_array_length(fill_bytes);
369 log_info(cds, heap)("Inserting filler obj array of %d elements (" SIZE_FORMAT " bytes total) @ buffer offset " SIZE_FORMAT,
370 array_length, fill_bytes, _buffer_used);
371 HeapWord* filler = init_filler_array_at_buffer_top(array_length, fill_bytes);
372 _buffer_used = filler_end;
373 _fillers->put((address)filler, fill_bytes);
374 }
375 }
376
377 size_t ArchiveHeapWriter::get_filler_size_at(address buffered_addr) {
378 size_t* p = _fillers->get(buffered_addr);
379 if (p != nullptr) {
380 assert(*p > 0, "filler must be larger than zero bytes");
381 return *p;
382 } else {
383 return 0; // buffered_addr is not a filler
384 }
385 }
386
387 template <typename T>
388 void update_buffered_object_field(address buffered_obj, int field_offset, T value) {
389 T* field_addr = cast_to_oop(buffered_obj)->field_addr<T>(field_offset);
390 *field_addr = value;
391 }
392
393 size_t ArchiveHeapWriter::copy_one_source_obj_to_buffer(oop src_obj) {
394 assert(!is_too_large_to_archive(src_obj), "already checked");
395 size_t byte_size = src_obj->size() * HeapWordSize;
396 assert(byte_size > 0, "no zero-size objects");
397
398 // For region-based collectors such as G1, the archive heap may be mapped into
399 // multiple regions. We need to make sure that we don't have an object that can possible
400 // span across two regions.
401 maybe_fill_gc_region_gap(byte_size);
402
403 size_t new_used = _buffer_used + byte_size;
404 assert(new_used > _buffer_used, "no wrap around");
405
406 size_t cur_min_region_bottom = align_down(_buffer_used, MIN_GC_REGION_ALIGNMENT);
407 size_t next_min_region_bottom = align_down(new_used, MIN_GC_REGION_ALIGNMENT);
408 assert(cur_min_region_bottom == next_min_region_bottom, "no object should cross minimal GC region boundaries");
409
410 ensure_buffer_space(new_used);
411
412 address from = cast_from_oop<address>(src_obj);
413 address to = offset_to_buffered_address<address>(_buffer_used);
414 assert(is_object_aligned(_buffer_used), "sanity");
415 assert(is_object_aligned(byte_size), "sanity");
416 memcpy(to, from, byte_size);
417
418 // These native pointers will be restored explicitly at run time.
419 if (java_lang_Module::is_instance(src_obj)) {
420 update_buffered_object_field<ModuleEntry*>(to, java_lang_Module::module_entry_offset(), nullptr);
421 } else if (java_lang_ClassLoader::is_instance(src_obj)) {
422 #ifdef ASSERT
423 // We only archive these loaders
424 if (src_obj != SystemDictionary::java_platform_loader() &&
425 src_obj != SystemDictionary::java_system_loader()) {
426 assert(src_obj->klass()->name()->equals("jdk/internal/loader/ClassLoaders$BootClassLoader"), "must be");
427 }
428 #endif
429 update_buffered_object_field<ClassLoaderData*>(to, java_lang_ClassLoader::loader_data_offset(), nullptr);
430 }
431
432 size_t buffered_obj_offset = _buffer_used;
433 _buffer_used = new_used;
434
435 return buffered_obj_offset;
436 }
437
438 void ArchiveHeapWriter::set_requested_address(ArchiveHeapInfo* info) {
439 assert(!info->is_used(), "only set once");
440 assert(UseG1GC, "must be");
441 address heap_end = (address)G1CollectedHeap::heap()->reserved().end();
442 log_info(cds, heap)("Heap end = %p", heap_end);
443
444 size_t heap_region_byte_size = _buffer_used;
445 assert(heap_region_byte_size > 0, "must archived at least one object!");
446
447
448 if (UseCompressedOops) {
449 _requested_bottom = align_down(heap_end - heap_region_byte_size, HeapRegion::GrainBytes);
450 } else {
451 // We always write the objects as if the heap started at this address. This
452 // makes the contents of the archive heap deterministic.
453 //
454 // Note that at runtime, the heap address is selected by the OS, so the archive
455 // heap will not be mapped at 0x10000000, and the contents need to be patched.
456 _requested_bottom = (address)NOCOOPS_REQUESTED_BASE;
457 }
458
459 assert(is_aligned(_requested_bottom, HeapRegion::GrainBytes), "sanity");
460
461 _requested_top = _requested_bottom + _buffer_used;
462
463 info->set_buffer_region(MemRegion(offset_to_buffered_address<HeapWord*>(0),
464 offset_to_buffered_address<HeapWord*>(_buffer_used)));
465 info->set_heap_roots_offset(_heap_roots_offset);
466 }
467
468 // Oop relocation
469
470 template <typename T> T* ArchiveHeapWriter::requested_addr_to_buffered_addr(T* p) {
471 assert(is_in_requested_range(cast_to_oop(p)), "must be");
472
473 address addr = address(p);
474 assert(addr >= _requested_bottom, "must be");
475 size_t offset = addr - _requested_bottom;
476 return offset_to_buffered_address<T*>(offset);
477 }
478
479 template <typename T> oop ArchiveHeapWriter::load_source_oop_from_buffer(T* buffered_addr) {
480 oop o = load_oop_from_buffer(buffered_addr);
481 assert(!in_buffer(cast_from_oop<address>(o)), "must point to source oop");
482 return o;
483 }
484
485 template <typename T> void ArchiveHeapWriter::store_requested_oop_in_buffer(T* buffered_addr,
486 oop request_oop) {
487 assert(is_in_requested_range(request_oop), "must be");
488 store_oop_in_buffer(buffered_addr, request_oop);
489 }
490
491 inline void ArchiveHeapWriter::store_oop_in_buffer(oop* buffered_addr, oop requested_obj) {
492 *buffered_addr = requested_obj;
493 }
494
495 inline void ArchiveHeapWriter::store_oop_in_buffer(narrowOop* buffered_addr, oop requested_obj) {
496 narrowOop val = CompressedOops::encode_not_null(requested_obj);
497 *buffered_addr = val;
498 }
499
500 oop ArchiveHeapWriter::load_oop_from_buffer(oop* buffered_addr) {
501 return *buffered_addr;
502 }
503
504 oop ArchiveHeapWriter::load_oop_from_buffer(narrowOop* buffered_addr) {
505 return CompressedOops::decode(*buffered_addr);
506 }
507
508 template <typename T> void ArchiveHeapWriter::relocate_field_in_buffer(T* field_addr_in_buffer, CHeapBitMap* oopmap) {
509 oop source_referent = load_source_oop_from_buffer<T>(field_addr_in_buffer);
510 if (!CompressedOops::is_null(source_referent)) {
511 oop request_referent = source_obj_to_requested_obj(source_referent);
512 store_requested_oop_in_buffer<T>(field_addr_in_buffer, request_referent);
513 mark_oop_pointer<T>(field_addr_in_buffer, oopmap);
514 }
515 }
516
517 template <typename T> void ArchiveHeapWriter::mark_oop_pointer(T* buffered_addr, CHeapBitMap* oopmap) {
518 T* request_p = (T*)(buffered_addr_to_requested_addr((address)buffered_addr));
519 address requested_region_bottom;
520
521 assert(request_p >= (T*)_requested_bottom, "sanity");
522 assert(request_p < (T*)_requested_top, "sanity");
523 requested_region_bottom = _requested_bottom;
524
525 // Mark the pointer in the oopmap
526 T* region_bottom = (T*)requested_region_bottom;
527 assert(request_p >= region_bottom, "must be");
528 BitMap::idx_t idx = request_p - region_bottom;
529 assert(idx < oopmap->size(), "overflow");
530 oopmap->set_bit(idx);
531 }
532
533 void ArchiveHeapWriter::update_header_for_requested_obj(oop requested_obj, oop src_obj, Klass* src_klass) {
534 assert(UseCompressedClassPointers, "Archived heap only supported for compressed klasses");
535 narrowKlass nk = ArchiveBuilder::current()->get_requested_narrow_klass(src_klass);
536 address buffered_addr = requested_addr_to_buffered_addr(cast_from_oop<address>(requested_obj));
537
538 oop fake_oop = cast_to_oop(buffered_addr);
539 if (!UseCompactObjectHeaders) {
540 fake_oop->set_narrow_klass(nk);
541 }
542
543 // We need to retain the identity_hash, because it may have been used by some hashtables
544 // in the shared heap. This also has the side effect of pre-initializing the
545 // identity_hash for all shared objects, so they are less likely to be written
546 // into during run time, increasing the potential of memory sharing.
547 if (src_obj != nullptr) {
548 intptr_t src_hash = src_obj->identity_hash();
549 if (UseCompactObjectHeaders) {
550 fake_oop->set_mark(markWord::prototype().set_narrow_klass(nk).copy_set_hash(src_hash));
551 } else {
552 fake_oop->set_mark(markWord::prototype().copy_set_hash(src_hash));
553 }
554 assert(fake_oop->mark().is_unlocked(), "sanity");
555
556 DEBUG_ONLY(intptr_t archived_hash = fake_oop->identity_hash());
557 assert(src_hash == archived_hash, "Different hash codes: original " INTPTR_FORMAT ", archived " INTPTR_FORMAT, src_hash, archived_hash);
558 }
559 }
560
561 // Relocate an element in the buffered copy of HeapShared::roots()
562 template <typename T> void ArchiveHeapWriter::relocate_root_at(oop requested_roots, int index, CHeapBitMap* oopmap) {
563 size_t offset = (size_t)((objArrayOop)requested_roots)->obj_at_offset<T>(index);
564 relocate_field_in_buffer<T>((T*)(buffered_heap_roots_addr() + offset), oopmap);
565 }
566
567 class ArchiveHeapWriter::EmbeddedOopRelocator: public BasicOopIterateClosure {
568 oop _src_obj;
569 address _buffered_obj;
570 CHeapBitMap* _oopmap;
571
572 public:
573 EmbeddedOopRelocator(oop src_obj, address buffered_obj, CHeapBitMap* oopmap) :
574 _src_obj(src_obj), _buffered_obj(buffered_obj), _oopmap(oopmap) {}
575
576 void do_oop(narrowOop *p) { EmbeddedOopRelocator::do_oop_work(p); }
577 void do_oop( oop *p) { EmbeddedOopRelocator::do_oop_work(p); }
578
579 private:
580 template <class T> void do_oop_work(T *p) {
581 size_t field_offset = pointer_delta(p, _src_obj, sizeof(char));
582 ArchiveHeapWriter::relocate_field_in_buffer<T>((T*)(_buffered_obj + field_offset), _oopmap);
583 }
584 };
585
586 static void log_bitmap_usage(const char* which, BitMap* bitmap, size_t total_bits) {
587 // The whole heap is covered by total_bits, but there are only non-zero bits within [start ... end).
588 size_t start = bitmap->find_first_set_bit(0);
589 size_t end = bitmap->size();
590 log_info(cds)("%s = " SIZE_FORMAT_W(7) " ... " SIZE_FORMAT_W(7) " (%3zu%% ... %3zu%% = %3zu%%)", which,
591 start, end,
592 start * 100 / total_bits,
593 end * 100 / total_bits,
594 (end - start) * 100 / total_bits);
595 }
596
597 // Update all oop fields embedded in the buffered objects
598 void ArchiveHeapWriter::relocate_embedded_oops(GrowableArrayCHeap<oop, mtClassShared>* roots,
599 ArchiveHeapInfo* heap_info) {
600 size_t oopmap_unit = (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop));
601 size_t heap_region_byte_size = _buffer_used;
602 heap_info->oopmap()->resize(heap_region_byte_size / oopmap_unit);
603
604 for (int i = 0; i < _source_objs_order->length(); i++) {
605 int src_obj_index = _source_objs_order->at(i)._index;
606 oop src_obj = _source_objs->at(src_obj_index);
607 HeapShared::CachedOopInfo* info = HeapShared::archived_object_cache()->get(src_obj);
608 assert(info != nullptr, "must be");
609 oop requested_obj = requested_obj_from_buffer_offset(info->buffer_offset());
610 update_header_for_requested_obj(requested_obj, src_obj, src_obj->klass());
611 address buffered_obj = offset_to_buffered_address<address>(info->buffer_offset());
612 EmbeddedOopRelocator relocator(src_obj, buffered_obj, heap_info->oopmap());
613 src_obj->oop_iterate(&relocator);
614 };
615
616 // Relocate HeapShared::roots(), which is created in copy_roots_to_buffer() and
617 // doesn't have a corresponding src_obj, so we can't use EmbeddedOopRelocator on it.
618 oop requested_roots = requested_obj_from_buffer_offset(_heap_roots_offset);
619 update_header_for_requested_obj(requested_roots, nullptr, Universe::objectArrayKlass());
620 int length = roots != nullptr ? roots->length() : 0;
621 for (int i = 0; i < length; i++) {
622 if (UseCompressedOops) {
623 relocate_root_at<narrowOop>(requested_roots, i, heap_info->oopmap());
624 } else {
625 relocate_root_at<oop>(requested_roots, i, heap_info->oopmap());
626 }
627 }
628
629 compute_ptrmap(heap_info);
630
631 size_t total_bytes = (size_t)_buffer->length();
632 log_bitmap_usage("oopmap", heap_info->oopmap(), total_bytes / (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop)));
633 log_bitmap_usage("ptrmap", heap_info->ptrmap(), total_bytes / sizeof(address));
634 }
635
636 void ArchiveHeapWriter::mark_native_pointer(oop src_obj, int field_offset) {
637 Metadata* ptr = src_obj->metadata_field_acquire(field_offset);
638 if (ptr != nullptr) {
639 NativePointerInfo info;
640 info._src_obj = src_obj;
641 info._field_offset = field_offset;
642 _native_pointers->append(info);
643 HeapShared::set_has_native_pointers(src_obj);
644 _num_native_ptrs ++;
645 }
646 }
647
648 // Do we have a jlong/jint field that's actually a pointer to a MetaspaceObj?
649 bool ArchiveHeapWriter::is_marked_as_native_pointer(ArchiveHeapInfo* heap_info, oop src_obj, int field_offset) {
650 HeapShared::CachedOopInfo* p = HeapShared::archived_object_cache()->get(src_obj);
651 assert(p != nullptr, "must be");
652
653 // requested_field_addr = the address of this field in the requested space
654 oop requested_obj = requested_obj_from_buffer_offset(p->buffer_offset());
655 Metadata** requested_field_addr = (Metadata**)(cast_from_oop<address>(requested_obj) + field_offset);
656 assert((Metadata**)_requested_bottom <= requested_field_addr && requested_field_addr < (Metadata**) _requested_top, "range check");
657
658 BitMap::idx_t idx = requested_field_addr - (Metadata**) _requested_bottom;
659 // Leading zeros have been removed so some addresses may not be in the ptrmap
660 size_t start_pos = FileMapInfo::current_info()->heap_ptrmap_start_pos();
661 if (idx < start_pos) {
662 return false;
663 } else {
664 idx -= start_pos;
665 }
666 return (idx < heap_info->ptrmap()->size()) && (heap_info->ptrmap()->at(idx) == true);
667 }
668
669 void ArchiveHeapWriter::compute_ptrmap(ArchiveHeapInfo* heap_info) {
670 int num_non_null_ptrs = 0;
671 Metadata** bottom = (Metadata**) _requested_bottom;
672 Metadata** top = (Metadata**) _requested_top; // exclusive
673 heap_info->ptrmap()->resize(top - bottom);
674
675 BitMap::idx_t max_idx = 32; // paranoid - don't make it too small
676 for (int i = 0; i < _native_pointers->length(); i++) {
677 NativePointerInfo info = _native_pointers->at(i);
678 oop src_obj = info._src_obj;
679 int field_offset = info._field_offset;
680 HeapShared::CachedOopInfo* p = HeapShared::archived_object_cache()->get(src_obj);
681 // requested_field_addr = the address of this field in the requested space
682 oop requested_obj = requested_obj_from_buffer_offset(p->buffer_offset());
683 Metadata** requested_field_addr = (Metadata**)(cast_from_oop<address>(requested_obj) + field_offset);
684 assert(bottom <= requested_field_addr && requested_field_addr < top, "range check");
685
686 // Mark this field in the bitmap
687 BitMap::idx_t idx = requested_field_addr - bottom;
688 heap_info->ptrmap()->set_bit(idx);
689 num_non_null_ptrs ++;
690 max_idx = MAX2(max_idx, idx);
691
692 // Set the native pointer to the requested address of the metadata (at runtime, the metadata will have
693 // this address if the RO/RW regions are mapped at the default location).
694
695 Metadata** buffered_field_addr = requested_addr_to_buffered_addr(requested_field_addr);
696 Metadata* native_ptr = *buffered_field_addr;
697 assert(native_ptr != nullptr, "sanity");
698
699 address buffered_native_ptr = ArchiveBuilder::current()->get_buffered_addr((address)native_ptr);
700 address requested_native_ptr = ArchiveBuilder::current()->to_requested(buffered_native_ptr);
701 *buffered_field_addr = (Metadata*)requested_native_ptr;
702 }
703
704 heap_info->ptrmap()->resize(max_idx + 1);
705 log_info(cds, heap)("calculate_ptrmap: marked %d non-null native pointers for heap region (" SIZE_FORMAT " bits)",
706 num_non_null_ptrs, size_t(heap_info->ptrmap()->size()));
707 }
708
709 #endif // INCLUDE_CDS_JAVA_HEAP