1 /*
  2  * Copyright (c) 2023, 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 "cds/regeneratedClasses.hpp"
 31 #include "classfile/javaClasses.hpp"
 32 #include "classfile/systemDictionary.hpp"
 33 #include "gc/shared/collectedHeap.hpp"
 34 #include "memory/iterator.inline.hpp"
 35 #include "memory/oopFactory.hpp"
 36 #include "memory/universe.hpp"
 37 #include "oops/compressedOops.hpp"
 38 #include "oops/oop.inline.hpp"
 39 #include "oops/objArrayOop.inline.hpp"
 40 #include "oops/oopHandle.inline.hpp"
 41 #include "oops/typeArrayKlass.hpp"
 42 #include "oops/typeArrayOop.hpp"
 43 #include "runtime/java.hpp"
 44 #include "runtime/mutexLocker.hpp"
 45 #include "utilities/bitMap.inline.hpp"
 46 #if INCLUDE_G1GC
 47 #include "gc/g1/g1CollectedHeap.hpp"
 48 #include "gc/g1/g1HeapRegion.hpp"
 49 #endif
 50 
 51 #if INCLUDE_CDS_JAVA_HEAP
 52 
 53 GrowableArrayCHeap<u1, mtClassShared>* ArchiveHeapWriter::_buffer = nullptr;
 54 
 55 // The following are offsets from buffer_bottom()
 56 size_t ArchiveHeapWriter::_buffer_used;
 57 
 58 // Heap root segments
 59 HeapRootSegments ArchiveHeapWriter::_heap_root_segments;
 60 
 61 address ArchiveHeapWriter::_requested_bottom;
 62 address ArchiveHeapWriter::_requested_top;
 63 
 64 static size_t _num_strings = 0;
 65 static size_t _string_bytes = 0; 
 66 static size_t _num_packages = 0;
 67 static size_t _num_protection_domains = 0;
 68 
 69 GrowableArrayCHeap<ArchiveHeapWriter::NativePointerInfo, mtClassShared>* ArchiveHeapWriter::_native_pointers;
 70 GrowableArrayCHeap<oop, mtClassShared>* ArchiveHeapWriter::_source_objs;
 71 GrowableArrayCHeap<ArchiveHeapWriter::HeapObjOrder, mtClassShared>* ArchiveHeapWriter::_source_objs_order;
 72 
 73 ArchiveHeapWriter::BufferOffsetToSourceObjectTable*
 74   ArchiveHeapWriter::_buffer_offset_to_source_obj_table = nullptr;
 75 
 76 
 77 typedef ResourceHashtable<
 78       size_t,    // offset of a filler from ArchiveHeapWriter::buffer_bottom()
 79       size_t,    // size of this filler (in bytes)
 80       127,       // prime number
 81       AnyObj::C_HEAP,
 82       mtClassShared> FillersTable;
 83 static FillersTable* _fillers;
 84 static int _num_native_ptrs = 0;
 85 
 86 void ArchiveHeapWriter::init() {
 87   if (HeapShared::can_write()) {
 88     Universe::heap()->collect(GCCause::_java_lang_system_gc);
 89 
 90     _buffer_offset_to_source_obj_table = new BufferOffsetToSourceObjectTable(/*size (prime)*/36137, /*max size*/1 * M);
 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 }
101 
102 void ArchiveHeapWriter::add_source_obj(oop src_obj) {
103   _source_objs->append(src_obj);
104 }
105 
106 void ArchiveHeapWriter::write(GrowableArrayCHeap<oop, mtClassShared>* roots,
107                               ArchiveHeapInfo* heap_info) {
108   assert(HeapShared::can_write(), "sanity");
109   allocate_buffer();
110   copy_source_objs_to_buffer(roots);
111   set_requested_address(heap_info);
112   relocate_embedded_oops(roots, heap_info);
113 }
114 
115 bool ArchiveHeapWriter::is_too_large_to_archive(oop o) {
116   return is_too_large_to_archive(o->size());
117 }
118 
119 bool ArchiveHeapWriter::is_string_too_large_to_archive(oop string) {
120   typeArrayOop value = java_lang_String::value_no_keepalive(string);
121   return is_too_large_to_archive(value);
122 }
123 
124 bool ArchiveHeapWriter::is_too_large_to_archive(size_t size) {
125   assert(size > 0, "no zero-size object");
126   assert(size * HeapWordSize > size, "no overflow");
127   static_assert(MIN_GC_REGION_ALIGNMENT > 0, "must be positive");
128 
129   size_t byte_size = size * HeapWordSize;
130   if (byte_size > size_t(MIN_GC_REGION_ALIGNMENT)) {
131     return true;
132   } else {
133     return false;
134   }
135 }
136 
137 // Various lookup functions between source_obj, buffered_obj and requested_obj
138 bool ArchiveHeapWriter::is_in_requested_range(oop o) {
139   assert(_requested_bottom != nullptr, "do not call before _requested_bottom is initialized");
140   address a = cast_from_oop<address>(o);
141   return (_requested_bottom <= a && a < _requested_top);
142 }
143 
144 oop ArchiveHeapWriter::requested_obj_from_buffer_offset(size_t offset) {
145   oop req_obj = cast_to_oop(_requested_bottom + offset);
146   assert(is_in_requested_range(req_obj), "must be");
147   return req_obj;
148 }
149 
150 oop ArchiveHeapWriter::source_obj_to_requested_obj(oop src_obj) {
151   assert(CDSConfig::is_dumping_heap(), "dump-time only");
152   HeapShared::CachedOopInfo* p = HeapShared::archived_object_cache()->get(src_obj);
153   if (p != nullptr) {
154     return requested_obj_from_buffer_offset(p->buffer_offset());
155   } else {
156     return nullptr;
157   }
158 }
159 
160 oop ArchiveHeapWriter::buffered_addr_to_source_obj(address buffered_addr) {
161   oop* p = _buffer_offset_to_source_obj_table->get(buffered_address_to_offset(buffered_addr));
162   if (p != nullptr) {
163     return *p;
164   } else {
165     return nullptr;
166   }
167 }
168 
169 address ArchiveHeapWriter::buffered_addr_to_requested_addr(address buffered_addr) {
170   return _requested_bottom + buffered_address_to_offset(buffered_addr);
171 }
172 
173 address ArchiveHeapWriter::requested_address() {
174   assert(_buffer != nullptr, "must be initialized");
175   return _requested_bottom;
176 }
177 
178 void ArchiveHeapWriter::allocate_buffer() {
179   int initial_buffer_size = 100000;
180   _buffer = new GrowableArrayCHeap<u1, mtClassShared>(initial_buffer_size);
181   _buffer_used = 0;
182   ensure_buffer_space(1); // so that buffer_bottom() works
183 }
184 
185 void ArchiveHeapWriter::ensure_buffer_space(size_t min_bytes) {
186   // We usually have very small heaps. If we get a huge one it's probably caused by a bug.
187   guarantee(min_bytes <= max_jint, "we dont support archiving more than 2G of objects");
188   _buffer->at_grow(to_array_index(min_bytes));
189 }
190 
191 objArrayOop ArchiveHeapWriter::allocate_root_segment(size_t offset, int element_count) {
192   HeapWord* mem = offset_to_buffered_address<HeapWord *>(offset);
193   memset(mem, 0, objArrayOopDesc::object_size(element_count));
194 
195   // The initialization code is copied from MemAllocator::finish and ObjArrayAllocator::initialize.
196   oopDesc::set_mark(mem, markWord::prototype());
197   oopDesc::release_set_klass(mem, Universe::objectArrayKlass());
198   arrayOopDesc::set_length(mem, element_count);
199   return objArrayOop(cast_to_oop(mem));
200 }
201 
202 void ArchiveHeapWriter::root_segment_at_put(objArrayOop segment, int index, oop root) {
203   // Do not use arrayOop->obj_at_put(i, o) as arrayOop is outside the real heap!
204   if (UseCompressedOops) {
205     *segment->obj_at_addr<narrowOop>(index) = CompressedOops::encode(root);
206   } else {
207     *segment->obj_at_addr<oop>(index) = root;
208   }
209 }
210 
211 void ArchiveHeapWriter::copy_roots_to_buffer(GrowableArrayCHeap<oop, mtClassShared>* roots) {
212   // Depending on the number of classes we are archiving, a single roots array may be
213   // larger than MIN_GC_REGION_ALIGNMENT. Roots are allocated first in the buffer, which
214   // allows us to chop the large array into a series of "segments". Current layout
215   // starts with zero or more segments exactly fitting MIN_GC_REGION_ALIGNMENT, and end
216   // with a single segment that may be smaller than MIN_GC_REGION_ALIGNMENT.
217   // This is simple and efficient. We do not need filler objects anywhere between the segments,
218   // or immediately after the last segment. This allows starting the object dump immediately
219   // after the roots.
220 
221   assert((_buffer_used % MIN_GC_REGION_ALIGNMENT) == 0,
222          "Pre-condition: Roots start at aligned boundary: " SIZE_FORMAT, _buffer_used);
223 
224   int max_elem_count = ((MIN_GC_REGION_ALIGNMENT - arrayOopDesc::header_size_in_bytes()) / heapOopSize);
225   assert(objArrayOopDesc::object_size(max_elem_count)*HeapWordSize == MIN_GC_REGION_ALIGNMENT,
226          "Should match exactly");
227 
228   HeapRootSegments segments(_buffer_used,
229                             roots->length(),
230                             MIN_GC_REGION_ALIGNMENT,
231                             max_elem_count);
232 
233   int root_index = 0;
234   for (size_t seg_idx = 0; seg_idx < segments.count(); seg_idx++) {
235     int size_elems = segments.size_in_elems(seg_idx);
236     size_t size_bytes = segments.size_in_bytes(seg_idx);
237 
238     size_t oop_offset = _buffer_used;
239     _buffer_used = oop_offset + size_bytes;
240     ensure_buffer_space(_buffer_used);
241 
242     assert((oop_offset % MIN_GC_REGION_ALIGNMENT) == 0,
243            "Roots segment " SIZE_FORMAT " start is not aligned: " SIZE_FORMAT,
244            segments.count(), oop_offset);
245 
246     objArrayOop seg_oop = allocate_root_segment(oop_offset, size_elems);
247     for (int i = 0; i < size_elems; i++) {
248       root_segment_at_put(seg_oop, i, roots->at(root_index++));
249     }
250 
251     log_info(cds, heap)("archived obj root segment [%d] = " SIZE_FORMAT " bytes, obj = " PTR_FORMAT,
252                         size_elems, size_bytes, p2i(seg_oop));
253   }
254 
255   _heap_root_segments = segments;
256 }
257 
258 // The goal is to sort the objects in increasing order of:
259 // - objects that have only oop pointers
260 // - objects that have both native and oop pointers
261 // - objects that have only native pointers
262 // - objects that have no pointers
263 static int oop_sorting_rank(oop o) {
264   bool has_oop_ptr, has_native_ptr;
265   HeapShared::get_pointer_info(o, has_oop_ptr, has_native_ptr);
266 
267   if (has_oop_ptr) {
268     if (!has_native_ptr) {
269       return 0;
270     } else {
271       return 1;
272     }
273   } else {
274     if (has_native_ptr) {
275       return 2;
276     } else {
277       return 3;
278     }
279   }
280 }
281 
282 int ArchiveHeapWriter::compare_objs_by_oop_fields(HeapObjOrder* a, HeapObjOrder* b) {
283   int rank_a = a->_rank;
284   int rank_b = b->_rank;
285 
286   if (rank_a != rank_b) {
287     return rank_a - rank_b;
288   } else {
289     // If they are the same rank, sort them by their position in the _source_objs array
290     return a->_index - b->_index;
291   }
292 }
293 
294 void ArchiveHeapWriter::sort_source_objs() {
295   log_info(cds)("sorting heap objects");
296   int len = _source_objs->length();
297   _source_objs_order = new GrowableArrayCHeap<HeapObjOrder, mtClassShared>(len);
298 
299   for (int i = 0; i < len; i++) {
300     oop o = _source_objs->at(i);
301     int rank = oop_sorting_rank(o);
302     HeapObjOrder os = {i, rank};
303     _source_objs_order->append(os);
304   }
305   log_info(cds)("computed ranks");
306   _source_objs_order->sort(compare_objs_by_oop_fields);
307   log_info(cds)("sorting heap objects done");
308 }
309 
310 void ArchiveHeapWriter::copy_source_objs_to_buffer(GrowableArrayCHeap<oop, mtClassShared>* roots) {
311   // There could be multiple root segments, which we want to be aligned by region.
312   // Putting them ahead of objects makes sure we waste no space.
313   copy_roots_to_buffer(roots);
314 
315   sort_source_objs();
316   for (int i = 0; i < _source_objs_order->length(); i++) {
317     int src_obj_index = _source_objs_order->at(i)._index;
318     oop src_obj = _source_objs->at(src_obj_index);
319     HeapShared::CachedOopInfo* info = HeapShared::archived_object_cache()->get(src_obj);
320     assert(info != nullptr, "must be");
321     size_t buffer_offset = copy_one_source_obj_to_buffer(src_obj);
322     info->set_buffer_offset(buffer_offset);
323 
324     _buffer_offset_to_source_obj_table->put_when_absent(buffer_offset, src_obj);
325     _buffer_offset_to_source_obj_table->maybe_grow();
326   }
327 
328   log_info(cds)("Size of heap region = " SIZE_FORMAT " bytes, %d objects, %d roots, %d native ptrs",
329                 _buffer_used, _source_objs->length() + 1, roots->length(), _num_native_ptrs);
330   log_info(cds)("   strings            = " SIZE_FORMAT_W(8) " (" SIZE_FORMAT " bytes)", _num_strings, _string_bytes);
331   log_info(cds)("   packages           = " SIZE_FORMAT_W(8), _num_packages);
332   log_info(cds)("   protection domains = " SIZE_FORMAT_W(8),_num_protection_domains);
333 }
334 
335 size_t ArchiveHeapWriter::filler_array_byte_size(int length) {
336   size_t byte_size = objArrayOopDesc::object_size(length) * HeapWordSize;
337   return byte_size;
338 }
339 
340 int ArchiveHeapWriter::filler_array_length(size_t fill_bytes) {
341   assert(is_object_aligned(fill_bytes), "must be");
342   size_t elemSize = (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop));
343 
344   int initial_length = to_array_length(fill_bytes / elemSize);
345   for (int length = initial_length; length >= 0; length --) {
346     size_t array_byte_size = filler_array_byte_size(length);
347     if (array_byte_size == fill_bytes) {
348       return length;
349     }
350   }
351 
352   ShouldNotReachHere();
353   return -1;
354 }
355 
356 HeapWord* ArchiveHeapWriter::init_filler_array_at_buffer_top(int array_length, size_t fill_bytes) {
357   assert(UseCompressedClassPointers, "Archived heap only supported for compressed klasses");
358   Klass* oak = Universe::objectArrayKlass(); // already relocated to point to archived klass
359   HeapWord* mem = offset_to_buffered_address<HeapWord*>(_buffer_used);
360   memset(mem, 0, fill_bytes);
361   oopDesc::set_mark(mem, markWord::prototype());
362   narrowKlass nk = ArchiveBuilder::current()->get_requested_narrow_klass(oak);
363   cast_to_oop(mem)->set_narrow_klass(nk);
364   arrayOopDesc::set_length(mem, array_length);
365   return mem;
366 }
367 
368 void ArchiveHeapWriter::maybe_fill_gc_region_gap(size_t required_byte_size) {
369   // We fill only with arrays (so we don't need to use a single HeapWord filler if the
370   // leftover space is smaller than a zero-sized array object). Therefore, we need to
371   // make sure there's enough space of min_filler_byte_size in the current region after
372   // required_byte_size has been allocated. If not, fill the remainder of the current
373   // region.
374   size_t min_filler_byte_size = filler_array_byte_size(0);
375   size_t new_used = _buffer_used + required_byte_size + min_filler_byte_size;
376 
377   const size_t cur_min_region_bottom = align_down(_buffer_used, MIN_GC_REGION_ALIGNMENT);
378   const size_t next_min_region_bottom = align_down(new_used, MIN_GC_REGION_ALIGNMENT);
379 
380   if (cur_min_region_bottom != next_min_region_bottom) {
381     // Make sure that no objects span across MIN_GC_REGION_ALIGNMENT. This way
382     // we can map the region in any region-based collector.
383     assert(next_min_region_bottom > cur_min_region_bottom, "must be");
384     assert(next_min_region_bottom - cur_min_region_bottom == MIN_GC_REGION_ALIGNMENT,
385            "no buffered object can be larger than %d bytes",  MIN_GC_REGION_ALIGNMENT);
386 
387     const size_t filler_end = next_min_region_bottom;
388     const size_t fill_bytes = filler_end - _buffer_used;
389     assert(fill_bytes > 0, "must be");
390     ensure_buffer_space(filler_end);
391 
392     int array_length = filler_array_length(fill_bytes);
393     log_info(cds, heap)("Inserting filler obj array of %d elements (" SIZE_FORMAT " bytes total) @ buffer offset " SIZE_FORMAT,
394                         array_length, fill_bytes, _buffer_used);
395     HeapWord* filler = init_filler_array_at_buffer_top(array_length, fill_bytes);
396     _buffer_used = filler_end;
397     _fillers->put(buffered_address_to_offset((address)filler), fill_bytes);
398   }
399 }
400 
401 size_t ArchiveHeapWriter::get_filler_size_at(address buffered_addr) {
402   size_t* p = _fillers->get(buffered_address_to_offset(buffered_addr));
403   if (p != nullptr) {
404     assert(*p > 0, "filler must be larger than zero bytes");
405     return *p;
406   } else {
407     return 0; // buffered_addr is not a filler
408   }
409 }
410 
411 template <typename T>
412 void update_buffered_object_field(address buffered_obj, int field_offset, T value) {
413   T* field_addr = cast_to_oop(buffered_obj)->field_addr<T>(field_offset);
414   *field_addr = value;
415 }
416 
417 void ArchiveHeapWriter::update_stats(oop src_obj) {
418   if (java_lang_String::is_instance(src_obj)) {
419     _num_strings ++;
420     _string_bytes += src_obj->size() * HeapWordSize;
421     _string_bytes += java_lang_String::value(src_obj)->size() * HeapWordSize;
422   } else {
423     Klass* k = src_obj->klass();
424     Symbol* name = k->name();
425     if (name->equals("java/lang/NamedPackage") || name->equals("java/lang/Package")) {
426       _num_packages ++;
427     } else if (name->equals("java/security/ProtectionDomain")) {
428       _num_protection_domains ++;
429     }
430   }
431 }
432 
433 size_t ArchiveHeapWriter::copy_one_source_obj_to_buffer(oop src_obj) {
434   update_stats(src_obj);
435 
436   assert(!is_too_large_to_archive(src_obj), "already checked");
437   size_t byte_size = src_obj->size() * HeapWordSize;
438   assert(byte_size > 0, "no zero-size objects");
439 
440   // For region-based collectors such as G1, the archive heap may be mapped into
441   // multiple regions. We need to make sure that we don't have an object that can possible
442   // span across two regions.
443   maybe_fill_gc_region_gap(byte_size);
444 
445   size_t new_used = _buffer_used + byte_size;
446   assert(new_used > _buffer_used, "no wrap around");
447 
448   size_t cur_min_region_bottom = align_down(_buffer_used, MIN_GC_REGION_ALIGNMENT);
449   size_t next_min_region_bottom = align_down(new_used, MIN_GC_REGION_ALIGNMENT);
450   assert(cur_min_region_bottom == next_min_region_bottom, "no object should cross minimal GC region boundaries");
451 
452   ensure_buffer_space(new_used);
453 
454   address from = cast_from_oop<address>(src_obj);
455   address to = offset_to_buffered_address<address>(_buffer_used);
456   assert(is_object_aligned(_buffer_used), "sanity");
457   assert(is_object_aligned(byte_size), "sanity");
458   memcpy(to, from, byte_size);
459 
460   // These native pointers will be restored explicitly at run time.
461   if (java_lang_Module::is_instance(src_obj)) {
462     update_buffered_object_field<ModuleEntry*>(to, java_lang_Module::module_entry_offset(), nullptr);
463   } else if (java_lang_ClassLoader::is_instance(src_obj)) {
464 #ifdef ASSERT
465     // We only archive these loaders
466     if (src_obj != SystemDictionary::java_platform_loader() &&
467         src_obj != SystemDictionary::java_system_loader()) {
468       assert(src_obj->klass()->name()->equals("jdk/internal/loader/ClassLoaders$BootClassLoader"), "must be");
469     }
470 #endif
471     update_buffered_object_field<ClassLoaderData*>(to, java_lang_ClassLoader::loader_data_offset(), nullptr);
472   }
473 
474   size_t buffered_obj_offset = _buffer_used;
475   _buffer_used = new_used;
476 
477   return buffered_obj_offset;
478 }
479 
480 void ArchiveHeapWriter::set_requested_address(ArchiveHeapInfo* info) {
481   assert(!info->is_used(), "only set once");
482 
483   size_t heap_region_byte_size = _buffer_used;
484   assert(heap_region_byte_size > 0, "must archived at least one object!");
485 
486   if (UseCompressedOops) {
487     if (UseG1GC) {
488       address heap_end = (address)G1CollectedHeap::heap()->reserved().end();
489       log_info(cds, heap)("Heap end = %p", heap_end);
490       _requested_bottom = align_down(heap_end - heap_region_byte_size, G1HeapRegion::GrainBytes);
491       _requested_bottom = align_down(_requested_bottom, MIN_GC_REGION_ALIGNMENT);
492       assert(is_aligned(_requested_bottom, G1HeapRegion::GrainBytes), "sanity");
493     } else {
494       _requested_bottom = align_up(CompressedOops::begin(), MIN_GC_REGION_ALIGNMENT);
495     }
496   } else {
497     // We always write the objects as if the heap started at this address. This
498     // makes the contents of the archive heap deterministic.
499     //
500     // Note that at runtime, the heap address is selected by the OS, so the archive
501     // heap will not be mapped at 0x10000000, and the contents need to be patched.
502     _requested_bottom = align_up((address)NOCOOPS_REQUESTED_BASE, MIN_GC_REGION_ALIGNMENT);
503   }
504 
505   assert(is_aligned(_requested_bottom, MIN_GC_REGION_ALIGNMENT), "sanity");
506 
507   _requested_top = _requested_bottom + _buffer_used;
508 
509   info->set_buffer_region(MemRegion(offset_to_buffered_address<HeapWord*>(0),
510                                     offset_to_buffered_address<HeapWord*>(_buffer_used)));
511   info->set_heap_root_segments(_heap_root_segments);
512 }
513 
514 // Oop relocation
515 
516 template <typename T> T* ArchiveHeapWriter::requested_addr_to_buffered_addr(T* p) {
517   assert(is_in_requested_range(cast_to_oop(p)), "must be");
518 
519   address addr = address(p);
520   assert(addr >= _requested_bottom, "must be");
521   size_t offset = addr - _requested_bottom;
522   return offset_to_buffered_address<T*>(offset);
523 }
524 
525 template <typename T> oop ArchiveHeapWriter::load_source_oop_from_buffer(T* buffered_addr) {
526   oop o = load_oop_from_buffer(buffered_addr);
527   assert(!in_buffer(cast_from_oop<address>(o)), "must point to source oop");
528   return o;
529 }
530 
531 template <typename T> void ArchiveHeapWriter::store_requested_oop_in_buffer(T* buffered_addr,
532                                                                             oop request_oop) {
533   assert(is_in_requested_range(request_oop), "must be");
534   store_oop_in_buffer(buffered_addr, request_oop);
535 }
536 
537 inline void ArchiveHeapWriter::store_oop_in_buffer(oop* buffered_addr, oop requested_obj) {
538   *buffered_addr = requested_obj;
539 }
540 
541 inline void ArchiveHeapWriter::store_oop_in_buffer(narrowOop* buffered_addr, oop requested_obj) {
542   narrowOop val = CompressedOops::encode_not_null(requested_obj);
543   *buffered_addr = val;
544 }
545 
546 oop ArchiveHeapWriter::load_oop_from_buffer(oop* buffered_addr) {
547   return *buffered_addr;
548 }
549 
550 oop ArchiveHeapWriter::load_oop_from_buffer(narrowOop* buffered_addr) {
551   return CompressedOops::decode(*buffered_addr);
552 }
553 
554 template <typename T> void ArchiveHeapWriter::relocate_field_in_buffer(T* field_addr_in_buffer, CHeapBitMap* oopmap) {
555   oop source_referent = load_source_oop_from_buffer<T>(field_addr_in_buffer);
556   if (source_referent != nullptr) {
557     if (java_lang_Class::is_instance(source_referent)) {
558       source_referent = HeapShared::scratch_java_mirror(source_referent);
559       assert(source_referent != nullptr, "must be");
560     }
561     oop request_referent = source_obj_to_requested_obj(source_referent);
562     store_requested_oop_in_buffer<T>(field_addr_in_buffer, request_referent);
563     mark_oop_pointer<T>(field_addr_in_buffer, oopmap);
564   }
565 }
566 
567 template <typename T> void ArchiveHeapWriter::mark_oop_pointer(T* buffered_addr, CHeapBitMap* oopmap) {
568   T* request_p = (T*)(buffered_addr_to_requested_addr((address)buffered_addr));
569   address requested_region_bottom;
570 
571   assert(request_p >= (T*)_requested_bottom, "sanity");
572   assert(request_p <  (T*)_requested_top, "sanity");
573   requested_region_bottom = _requested_bottom;
574 
575   // Mark the pointer in the oopmap
576   T* region_bottom = (T*)requested_region_bottom;
577   assert(request_p >= region_bottom, "must be");
578   BitMap::idx_t idx = request_p - region_bottom;
579   assert(idx < oopmap->size(), "overflow");
580   oopmap->set_bit(idx);
581 }
582 
583 void ArchiveHeapWriter::update_header_for_requested_obj(oop requested_obj, oop src_obj,  Klass* src_klass) {
584   assert(UseCompressedClassPointers, "Archived heap only supported for compressed klasses");
585   narrowKlass nk = ArchiveBuilder::current()->get_requested_narrow_klass(src_klass);
586   address buffered_addr = requested_addr_to_buffered_addr(cast_from_oop<address>(requested_obj));
587 
588   oop fake_oop = cast_to_oop(buffered_addr);
589   fake_oop->set_narrow_klass(nk);
590 
591   // We need to retain the identity_hash, because it may have been used by some hashtables
592   // in the shared heap.
593   if (src_obj != nullptr && !src_obj->fast_no_hash_check()) {
594     intptr_t src_hash = src_obj->identity_hash();
595     fake_oop->set_mark(markWord::prototype().copy_set_hash(src_hash));
596     assert(fake_oop->mark().is_unlocked(), "sanity");
597 
598     DEBUG_ONLY(intptr_t archived_hash = fake_oop->identity_hash());
599     assert(src_hash == archived_hash, "Different hash codes: original " INTPTR_FORMAT ", archived " INTPTR_FORMAT, src_hash, archived_hash);
600   }
601 }
602 
603 class ArchiveHeapWriter::EmbeddedOopRelocator: public BasicOopIterateClosure {
604   oop _src_obj;
605   address _buffered_obj;
606   CHeapBitMap* _oopmap;
607 
608 public:
609   EmbeddedOopRelocator(oop src_obj, address buffered_obj, CHeapBitMap* oopmap) :
610     _src_obj(src_obj), _buffered_obj(buffered_obj), _oopmap(oopmap) {}
611 
612   void do_oop(narrowOop *p) { EmbeddedOopRelocator::do_oop_work(p); }
613   void do_oop(      oop *p) { EmbeddedOopRelocator::do_oop_work(p); }
614 
615 private:
616   template <class T> void do_oop_work(T *p) {
617     size_t field_offset = pointer_delta(p, _src_obj, sizeof(char));
618     ArchiveHeapWriter::relocate_field_in_buffer<T>((T*)(_buffered_obj + field_offset), _oopmap);
619   }
620 };
621 
622 static void log_bitmap_usage(const char* which, BitMap* bitmap, size_t total_bits) {
623   // The whole heap is covered by total_bits, but there are only non-zero bits within [start ... end).
624   size_t start = bitmap->find_first_set_bit(0);
625   size_t end = bitmap->size();
626   log_info(cds)("%s = " SIZE_FORMAT_W(7) " ... " SIZE_FORMAT_W(7) " (%3zu%% ... %3zu%% = %3zu%%)", which,
627                 start, end,
628                 start * 100 / total_bits,
629                 end * 100 / total_bits,
630                 (end - start) * 100 / total_bits);
631 }
632 
633 // Update all oop fields embedded in the buffered objects
634 void ArchiveHeapWriter::relocate_embedded_oops(GrowableArrayCHeap<oop, mtClassShared>* roots,
635                                                ArchiveHeapInfo* heap_info) {
636   size_t oopmap_unit = (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop));
637   size_t heap_region_byte_size = _buffer_used;
638   heap_info->oopmap()->resize(heap_region_byte_size   / oopmap_unit);
639 
640   for (int i = 0; i < _source_objs_order->length(); i++) {
641     int src_obj_index = _source_objs_order->at(i)._index;
642     oop src_obj = _source_objs->at(src_obj_index);
643     HeapShared::CachedOopInfo* info = HeapShared::archived_object_cache()->get(src_obj);
644     assert(info != nullptr, "must be");
645     oop requested_obj = requested_obj_from_buffer_offset(info->buffer_offset());
646     update_header_for_requested_obj(requested_obj, src_obj, src_obj->klass());
647     address buffered_obj = offset_to_buffered_address<address>(info->buffer_offset());
648     EmbeddedOopRelocator relocator(src_obj, buffered_obj, heap_info->oopmap());
649     src_obj->oop_iterate(&relocator);
650   };
651 
652   // Relocate HeapShared::roots(), which is created in copy_roots_to_buffer() and
653   // doesn't have a corresponding src_obj, so we can't use EmbeddedOopRelocator on it.
654   for (size_t seg_idx = 0; seg_idx < _heap_root_segments.count(); seg_idx++) {
655     size_t seg_offset = _heap_root_segments.segment_offset(seg_idx);
656 
657     objArrayOop requested_obj = (objArrayOop)requested_obj_from_buffer_offset(seg_offset);
658     update_header_for_requested_obj(requested_obj, nullptr, Universe::objectArrayKlass());
659     address buffered_obj = offset_to_buffered_address<address>(seg_offset);
660     int length = _heap_root_segments.size_in_elems(seg_idx);
661 
662     if (UseCompressedOops) {
663       for (int i = 0; i < length; i++) {
664         narrowOop* addr = (narrowOop*)(buffered_obj + objArrayOopDesc::obj_at_offset<narrowOop>(i));
665         relocate_field_in_buffer<narrowOop>(addr, heap_info->oopmap());
666       }
667     } else {
668       for (int i = 0; i < length; i++) {
669         oop* addr = (oop*)(buffered_obj + objArrayOopDesc::obj_at_offset<oop>(i));
670         relocate_field_in_buffer<oop>(addr, heap_info->oopmap());
671       }
672     }
673   }
674 
675   compute_ptrmap(heap_info);
676 
677   size_t total_bytes = (size_t)_buffer->length();
678   log_bitmap_usage("oopmap", heap_info->oopmap(), total_bytes / (UseCompressedOops ? sizeof(narrowOop) : sizeof(oop)));
679   log_bitmap_usage("ptrmap", heap_info->ptrmap(), total_bytes / sizeof(address));
680 }
681 
682 void ArchiveHeapWriter::mark_native_pointer(oop src_obj, int field_offset) {
683   Metadata* ptr = src_obj->metadata_field_acquire(field_offset);
684   if (ptr != nullptr) {
685     NativePointerInfo info;
686     info._src_obj = src_obj;
687     info._field_offset = field_offset;
688     _native_pointers->append(info);
689     if (!ArchiveBuilder::current()->has_been_archived((address)ptr)) {
690       // Currently we supporting marking of only Method and Klass, both of which are
691       // subtypes of MetaData.
692       ResourceMark rm;
693       log_error(cds, heap)("Native pointer %p is not archived", ptr);
694       if (((Metadata*)ptr)->is_method()) {
695         log_error(cds, heap)("Method: %s", ((Method*)ptr)->external_name());
696       } else {
697         assert(((Metadata*)ptr)->is_klass(), "must be");
698         log_error(cds, heap)("Klass: %s", ((Klass*)ptr)->external_name());
699       }
700       HeapShared::exit_on_error();
701     }
702     HeapShared::set_has_native_pointers(src_obj);
703     _num_native_ptrs ++;
704   }
705 }
706 
707 // Do we have a jlong/jint field that's actually a pointer to a MetaspaceObj?
708 bool ArchiveHeapWriter::is_marked_as_native_pointer(ArchiveHeapInfo* heap_info, oop src_obj, int field_offset) {
709   HeapShared::CachedOopInfo* p = HeapShared::archived_object_cache()->get(src_obj);
710   assert(p != nullptr, "must be");
711 
712   // requested_field_addr = the address of this field in the requested space
713   oop requested_obj = requested_obj_from_buffer_offset(p->buffer_offset());
714   Metadata** requested_field_addr = (Metadata**)(cast_from_oop<address>(requested_obj) + field_offset);
715   assert((Metadata**)_requested_bottom <= requested_field_addr && requested_field_addr < (Metadata**) _requested_top, "range check");
716 
717   BitMap::idx_t idx = requested_field_addr - (Metadata**) _requested_bottom;
718   // Leading zeros have been removed so some addresses may not be in the ptrmap
719   size_t start_pos = FileMapInfo::current_info()->heap_ptrmap_start_pos();
720   if (idx < start_pos) {
721     return false;
722   } else {
723     idx -= start_pos;
724   }
725   return (idx < heap_info->ptrmap()->size()) && (heap_info->ptrmap()->at(idx) == true);
726 }
727 
728 void ArchiveHeapWriter::compute_ptrmap(ArchiveHeapInfo* heap_info) {
729   int num_non_null_ptrs = 0;
730   Metadata** bottom = (Metadata**) _requested_bottom;
731   Metadata** top = (Metadata**) _requested_top; // exclusive
732   heap_info->ptrmap()->resize(top - bottom);
733 
734   BitMap::idx_t max_idx = 32; // paranoid - don't make it too small
735   for (int i = 0; i < _native_pointers->length(); i++) {
736     NativePointerInfo info = _native_pointers->at(i);
737     oop src_obj = info._src_obj;
738     int field_offset = info._field_offset;
739     HeapShared::CachedOopInfo* p = HeapShared::archived_object_cache()->get(src_obj);
740     // requested_field_addr = the address of this field in the requested space
741     oop requested_obj = requested_obj_from_buffer_offset(p->buffer_offset());
742     Metadata** requested_field_addr = (Metadata**)(cast_from_oop<address>(requested_obj) + field_offset);
743     assert(bottom <= requested_field_addr && requested_field_addr < top, "range check");
744 
745     // Mark this field in the bitmap
746     BitMap::idx_t idx = requested_field_addr - bottom;
747     heap_info->ptrmap()->set_bit(idx);
748     num_non_null_ptrs ++;
749     max_idx = MAX2(max_idx, idx);
750 
751     // Set the native pointer to the requested address of the metadata (at runtime, the metadata will have
752     // this address if the RO/RW regions are mapped at the default location).
753 
754     Metadata** buffered_field_addr = requested_addr_to_buffered_addr(requested_field_addr);
755     Metadata* native_ptr = *buffered_field_addr;
756     assert(native_ptr != nullptr, "sanity");
757 
758     if (RegeneratedClasses::has_been_regenerated((address)native_ptr)) {
759       native_ptr = (Metadata*)RegeneratedClasses::get_regenerated_object((address)native_ptr);
760     }
761 
762     address buffered_native_ptr = ArchiveBuilder::current()->get_buffered_addr((address)native_ptr);
763     address requested_native_ptr = ArchiveBuilder::current()->to_requested(buffered_native_ptr);
764     *buffered_field_addr = (Metadata*)requested_native_ptr;
765   }
766 
767   heap_info->ptrmap()->resize(max_idx + 1);
768   log_info(cds, heap)("calculate_ptrmap: marked %d non-null native pointers for heap region (" SIZE_FORMAT " bits)",
769                       num_non_null_ptrs, size_t(heap_info->ptrmap()->size()));
770 }
771 
772 #endif // INCLUDE_CDS_JAVA_HEAP