1 /*
2 * Copyright (c) 2020, 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 #ifndef SHARE_CDS_ARCHIVEBUILDER_HPP
26 #define SHARE_CDS_ARCHIVEBUILDER_HPP
27
28 #include "cds/archiveUtils.hpp"
29 #include "cds/dumpAllocStats.hpp"
30 #include "memory/metaspace.hpp"
31 #include "memory/metaspaceClosure.hpp"
32 #include "memory/reservedSpace.hpp"
33 #include "memory/virtualspace.hpp"
34 #include "oops/array.hpp"
35 #include "oops/klass.hpp"
36 #include "runtime/os.hpp"
37 #include "utilities/bitMap.hpp"
38 #include "utilities/growableArray.hpp"
39 #include "utilities/resizeableResourceHash.hpp"
40 #include "utilities/resourceHash.hpp"
41
42 class ArchiveHeapInfo;
43 class CHeapBitMap;
44 class FileMapInfo;
45 class Klass;
46 class MemRegion;
47 class Symbol;
48
49 // The minimum alignment for non-Klass objects inside the CDS archive. Klass objects need
50 // to follow CompressedKlassPointers::klass_alignment_in_bytes().
51 constexpr size_t SharedSpaceObjectAlignment = Metaspace::min_allocation_alignment_bytes;
52
53 // Overview of CDS archive creation (for both static and dynamic dump):
54 //
55 // [1] Load all classes (static dump: from the classlist, dynamic dump: as part of app execution)
56 // [2] Allocate "output buffer"
57 // [3] Copy contents of the 2 "core" regions (rw/ro) into the output buffer.
58 // - allocate the cpp vtables in rw (static dump only)
59 // - memcpy the MetaspaceObjs into rw/ro:
60 // dump_rw_region();
61 // dump_ro_region();
62 // - fix all the pointers in the MetaspaceObjs to point to the copies
63 // relocate_metaspaceobj_embedded_pointers()
64 // [4] Copy symbol table, dictionary, etc, into the ro region
65 // [5] Relocate all the pointers in rw/ro, so that the archive can be mapped to
66 // the "requested" location without runtime relocation. See relocate_to_requested()
67 //
68 // "source" vs "buffered" vs "requested"
69 //
70 // The ArchiveBuilder deals with three types of addresses.
71 //
72 // "source": These are the addresses of objects created in step [1] above. They are the actual
73 // InstanceKlass*, Method*, etc, of the Java classes that are loaded for executing
74 // Java bytecodes in the JVM process that's dumping the CDS archive.
75 //
76 // It may be necessary to contiue Java execution after ArchiveBuilder is finished.
77 // Therefore, we don't modify any of the "source" objects.
78 //
79 // "buffered": The "source" objects that are deemed archivable are copied into a temporary buffer.
80 // Objects in the buffer are modified in steps [2, 3, 4] (e.g., unshareable info is
81 // removed, pointers are relocated, etc) to prepare them to be loaded at runtime.
82 //
83 // "requested": These are the addreses where the "buffered" objects should be loaded at runtime.
84 // When the "buffered" objects are written into the archive file, their addresses
85 // are adjusted in step [5] such that the lowest of these objects would be mapped
86 // at SharedBaseAddress.
87 //
88 // Translation between "source" and "buffered" addresses is done with two hashtables:
89 // _src_obj_table : "source" -> "buffered"
90 // _buffered_to_src_table : "buffered" -> "source"
91 //
92 // Translation between "buffered" and "requested" addresses is done with a simple shift:
93 // buffered_address + _buffer_to_requested_delta == requested_address
94 //
95 class ArchiveBuilder : public StackObj {
96 protected:
97 DumpRegion* _current_dump_region;
98 address _buffer_bottom; // for writing the contents of rw/ro regions
99 int _num_dump_regions_used;
100
101 // These are the addresses where we will request the static and dynamic archives to be
102 // mapped at run time. If the request fails (due to ASLR), we will map the archives at
103 // os-selected addresses.
104 address _requested_static_archive_bottom; // This is determined solely by the value of
105 // SharedBaseAddress during -Xshare:dump.
106 address _requested_static_archive_top;
107 address _requested_dynamic_archive_bottom; // Used only during dynamic dump. It's placed
108 // immediately above _requested_static_archive_top.
109 address _requested_dynamic_archive_top;
110
111 // (Used only during dynamic dump) where the static archive is actually mapped. This
112 // may be different than _requested_static_archive_{bottom,top} due to ASLR
113 address _mapped_static_archive_bottom;
114 address _mapped_static_archive_top;
115
116 intx _buffer_to_requested_delta;
117
118 DumpRegion* current_dump_region() const { return _current_dump_region; }
119
120 public:
121 enum FollowMode {
122 make_a_copy, point_to_it, set_to_null
123 };
124
125 private:
126 class SourceObjInfo {
127 uintx _ptrmap_start; // The bit-offset of the start of this object (inclusive)
128 uintx _ptrmap_end; // The bit-offset of the end of this object (exclusive)
129 bool _read_only;
130 bool _has_embedded_pointer;
131 FollowMode _follow_mode;
132 int _size_in_bytes;
133 int _id; // Each object has a unique serial ID, starting from zero. The ID is assigned
134 // when the object is added into _source_objs.
135 MetaspaceObj::Type _msotype;
136 address _source_addr; // The source object to be copied.
137 address _buffered_addr; // The copy of this object insider the buffer.
138 public:
139 SourceObjInfo(MetaspaceClosure::Ref* ref, bool read_only, FollowMode follow_mode) :
140 _ptrmap_start(0), _ptrmap_end(0), _read_only(read_only), _has_embedded_pointer(false), _follow_mode(follow_mode),
141 _size_in_bytes(ref->size() * BytesPerWord), _id(0), _msotype(ref->msotype()),
142 _source_addr(ref->obj()) {
143 if (follow_mode == point_to_it) {
144 _buffered_addr = ref->obj();
145 } else {
146 _buffered_addr = nullptr;
147 }
148 }
149 SourceObjInfo(address src, address buf) {
150 _source_addr = src;
151 _buffered_addr = buf;
152 }
153
154 // This constructor is only used for regenerated objects (created by LambdaFormInvokers, etc).
155 // src = address of a Method or InstanceKlass that has been regenerated.
156 // renegerated_obj_info = info for the regenerated version of src.
157 SourceObjInfo(address src, SourceObjInfo* renegerated_obj_info) :
158 _ptrmap_start(0), _ptrmap_end(0), _read_only(false),
159 _follow_mode(renegerated_obj_info->_follow_mode),
160 _size_in_bytes(0), _msotype(renegerated_obj_info->_msotype),
161 _source_addr(src), _buffered_addr(renegerated_obj_info->_buffered_addr) {}
162
163 bool should_copy() const { return _follow_mode == make_a_copy; }
164 void set_buffered_addr(address addr) {
165 assert(should_copy(), "must be");
166 assert(_buffered_addr == nullptr, "cannot be copied twice");
167 assert(addr != nullptr, "must be a valid copy");
168 _buffered_addr = addr;
169 }
170 void set_ptrmap_start(uintx v) { _ptrmap_start = v; }
171 void set_ptrmap_end(uintx v) { _ptrmap_end = v; }
172 uintx ptrmap_start() const { return _ptrmap_start; } // inclusive
173 uintx ptrmap_end() const { return _ptrmap_end; } // exclusive
174 bool read_only() const { return _read_only; }
175 bool has_embedded_pointer() const { return _has_embedded_pointer; }
176 void set_has_embedded_pointer() { _has_embedded_pointer = true; }
177 int size_in_bytes() const { return _size_in_bytes; }
178 int id() const { return _id; }
179 void set_id(int i) { _id = i; }
180 address source_addr() const { return _source_addr; }
181 address buffered_addr() const {
182 if (_follow_mode != set_to_null) {
183 assert(_buffered_addr != nullptr, "must be initialized");
184 }
185 return _buffered_addr;
186 }
187 MetaspaceObj::Type msotype() const { return _msotype; }
188 };
189
190 class SourceObjList {
191 uintx _total_bytes;
192 GrowableArray<SourceObjInfo*>* _objs; // Source objects to be archived
193 CHeapBitMap _ptrmap; // Marks the addresses of the pointer fields
194 // in the source objects
195 public:
196 SourceObjList();
197 ~SourceObjList();
198
199 GrowableArray<SourceObjInfo*>* objs() const { return _objs; }
200
201 void append(SourceObjInfo* src_info);
202 void remember_embedded_pointer(SourceObjInfo* pointing_obj, MetaspaceClosure::Ref* ref);
203 void relocate(int i, ArchiveBuilder* builder);
204
205 // convenience accessor
206 SourceObjInfo* at(int i) const { return objs()->at(i); }
207 };
208
209 class CDSMapLogger;
210
211 static const int INITIAL_TABLE_SIZE = 15889;
212 static const int MAX_TABLE_SIZE = 1000000;
213
214 ReservedSpace _shared_rs;
215 VirtualSpace _shared_vs;
216
217 DumpRegion _rw_region;
218 DumpRegion _ro_region;
219 DumpRegion _cc_region;
220
221 // Combined bitmap to track pointers in both RW and RO regions. This is updated
222 // as objects are copied into RW and RO.
223 CHeapBitMap _ptrmap;
224
225 // _ptrmap is split into these two bitmaps which are written into the archive.
226 CHeapBitMap _rw_ptrmap; // marks pointers in the RW region
227 CHeapBitMap _ro_ptrmap; // marks pointers in the RO region
228 CHeapBitMap _cc_ptrmap; // marks pointers in the CC region
229
230 SourceObjList _rw_src_objs; // objs to put in rw region
231 SourceObjList _ro_src_objs; // objs to put in ro region
232 ResizeableResourceHashtable<address, SourceObjInfo, AnyObj::C_HEAP, mtClassShared> _src_obj_table;
233 ResizeableResourceHashtable<address, address, AnyObj::C_HEAP, mtClassShared> _buffered_to_src_table;
234 GrowableArray<Klass*>* _klasses;
235 GrowableArray<Symbol*>* _symbols;
236 unsigned int _entropy_seed;
237
238 // statistics
239 DumpAllocStats _alloc_stats;
240 size_t _total_heap_region_size;
241
242 void print_region_stats(FileMapInfo *map_info, ArchiveHeapInfo* heap_info);
243 void print_bitmap_region_stats(size_t size, size_t total_size);
244 void print_heap_region_stats(ArchiveHeapInfo* heap_info, size_t total_size);
245
246 // For global access.
247 static ArchiveBuilder* _current;
248
249 public:
250 // Use this when you allocate space outside of ArchiveBuilder::dump_{rw,ro}_region.
251 // These are usually for misc tables that are allocated in the RO space.
252 class OtherROAllocMark {
253 char* _oldtop;
254 public:
255 OtherROAllocMark() {
256 _oldtop = _current->_ro_region.top();
257 }
258 ~OtherROAllocMark();
259 };
260
261 private:
262 FollowMode get_follow_mode(MetaspaceClosure::Ref *ref);
263
264 void iterate_sorted_roots(MetaspaceClosure* it);
265 void sort_klasses();
266 static int compare_symbols_by_address(Symbol** a, Symbol** b);
267 static int compare_klass_by_name(Klass** a, Klass** b);
268 void update_hidden_class_loader_type(InstanceKlass* ik) NOT_CDS_JAVA_HEAP_RETURN;
269
270 void make_shallow_copies(DumpRegion *dump_region, const SourceObjList* src_objs);
271 void make_shallow_copy(DumpRegion *dump_region, SourceObjInfo* src_info);
272
273 void relocate_embedded_pointers(SourceObjList* src_objs);
274
275 bool is_excluded(Klass* k);
276 void clean_up_src_obj_table();
277
278 protected:
279 virtual void iterate_roots(MetaspaceClosure* it) = 0;
280
281 static const int _total_dump_regions = 2;
282
283 void start_dump_region(DumpRegion* next);
284
285 public:
286 address reserve_buffer();
287
288 address buffer_bottom() const { return _buffer_bottom; }
289 address buffer_top() const { return (address)current_dump_region()->top(); }
290 address requested_static_archive_bottom() const { return _requested_static_archive_bottom; }
291 address mapped_static_archive_bottom() const { return _mapped_static_archive_bottom; }
292 intx buffer_to_requested_delta() const { return _buffer_to_requested_delta; }
293
294 bool is_in_buffer_space(address p) const {
295 return (buffer_bottom() != nullptr && buffer_bottom() <= p && p < buffer_top());
296 }
297
298 template <typename T> bool is_in_requested_static_archive(T p) const {
299 return _requested_static_archive_bottom <= (address)p && (address)p < _requested_static_archive_top;
300 }
301
302 template <typename T> bool is_in_mapped_static_archive(T p) const {
303 return _mapped_static_archive_bottom <= (address)p && (address)p < _mapped_static_archive_top;
304 }
305
306 template <typename T> bool is_in_buffer_space(T obj) const {
307 return is_in_buffer_space(address(obj));
308 }
309
310 template <typename T> T to_requested(T obj) const {
311 assert(is_in_buffer_space(obj), "must be");
312 return (T)(address(obj) + _buffer_to_requested_delta);
313 }
314
315 static intx get_buffer_to_requested_delta() {
316 return current()->buffer_to_requested_delta();
317 }
318
319 inline static u4 to_offset_u4(uintx offset) {
320 guarantee(offset <= MAX_SHARED_DELTA, "must be 32-bit offset " INTPTR_FORMAT, offset);
321 return (u4)offset;
322 }
323
324 public:
325 static const uintx MAX_SHARED_DELTA = ArchiveUtils::MAX_SHARED_DELTA;;
326
327 // The address p points to an object inside the output buffer. When the archive is mapped
328 // at the requested address, what's the offset of this object from _requested_static_archive_bottom?
329 uintx buffer_to_offset(address p) const;
330
331 // Same as buffer_to_offset, except that the address p points to either (a) an object
332 // inside the output buffer, or (b), an object in the currently mapped static archive.
333 uintx any_to_offset(address p) const;
334
335 // The reverse of buffer_to_offset()
336 address offset_to_buffered_address(u4 offset) const;
337
338 template <typename T>
339 u4 buffer_to_offset_u4(T p) const {
340 uintx offset = buffer_to_offset((address)p);
341 return to_offset_u4(offset);
342 }
343
344 template <typename T>
345 u4 any_to_offset_u4(T p) const {
346 assert(p != nullptr, "must not be null");
347 uintx offset = any_to_offset((address)p);
348 return to_offset_u4(offset);
349 }
350
351 template <typename T>
352 u4 any_or_null_to_offset_u4(T p) const {
353 if (p == nullptr) {
354 return 0;
355 } else {
356 return any_to_offset_u4<T>(p);
357 }
358 }
359
360 template <typename T>
361 T offset_to_buffered(u4 offset) const {
362 return (T)offset_to_buffered_address(offset);
363 }
364
365 public:
366 ArchiveBuilder();
367 ~ArchiveBuilder();
368
369 int entropy();
370 void gather_klasses_and_symbols();
371 void gather_source_objs();
372 bool gather_klass_and_symbol(MetaspaceClosure::Ref* ref, bool read_only);
373 bool gather_one_source_obj(MetaspaceClosure::Ref* ref, bool read_only);
374 void remember_embedded_pointer_in_enclosing_obj(MetaspaceClosure::Ref* ref);
375 static void serialize_dynamic_archivable_items(SerializeClosure* soc);
376
377 DumpRegion* rw_region() { return &_rw_region; }
378 DumpRegion* ro_region() { return &_ro_region; }
379 DumpRegion* cc_region() { return &_cc_region; }
380
381 void start_cc_region();
382 void end_cc_region();
383
384 static char* rw_region_alloc(size_t num_bytes) {
385 return current()->rw_region()->allocate(num_bytes);
386 }
387 static char* ro_region_alloc(size_t num_bytes) {
388 return current()->ro_region()->allocate(num_bytes);
389 }
390 static char* cc_region_alloc(size_t num_bytes) {
391 return current()->cc_region()->allocate(num_bytes);
392 }
393
394 template <typename T>
395 static Array<T>* new_ro_array(int length) {
396 size_t byte_size = Array<T>::byte_sizeof(length, sizeof(T));
397 Array<T>* array = (Array<T>*)ro_region_alloc(byte_size);
398 array->initialize(length);
399 return array;
400 }
401
402 template <typename T>
403 static Array<T>* new_rw_array(int length) {
404 size_t byte_size = Array<T>::byte_sizeof(length, sizeof(T));
405 Array<T>* array = (Array<T>*)rw_region_alloc(byte_size);
406 array->initialize(length);
407 return array;
408 }
409
410 template <typename T>
411 static size_t ro_array_bytesize(int length) {
412 size_t byte_size = Array<T>::byte_sizeof(length, sizeof(T));
413 return align_up(byte_size, SharedSpaceObjectAlignment);
414 }
415
416 char* ro_strdup(const char* s);
417
418 static int compare_src_objs(SourceObjInfo** a, SourceObjInfo** b);
419 void sort_metadata_objs();
420 void dump_rw_metadata();
421 void dump_ro_metadata();
422 void relocate_metaspaceobj_embedded_pointers();
423 void record_regenerated_object(address orig_src_obj, address regen_src_obj);
424 void make_klasses_shareable();
425 void make_training_data_shareable();
426 void relocate_to_requested();
427 void write_archive(FileMapInfo* mapinfo, ArchiveHeapInfo* heap_info);
428 void write_region(FileMapInfo* mapinfo, int region_idx, DumpRegion* dump_region,
429 bool read_only, bool allow_exec);
430
431 void write_pointer_in_buffer(address* ptr_location, address src_addr);
432 template <typename T> void write_pointer_in_buffer(T* ptr_location, T src_addr) {
433 write_pointer_in_buffer((address*)ptr_location, (address)src_addr);
434 }
435
436 void mark_and_relocate_to_buffered_addr(address* ptr_location);
437 template <typename T> void mark_and_relocate_to_buffered_addr(T ptr_location) {
438 mark_and_relocate_to_buffered_addr((address*)ptr_location);
439 }
440
441 bool has_been_archived(address src_addr) const;
442
443 bool has_been_buffered(address src_addr) const;
444 template <typename T> bool has_been_buffered(T src_addr) const {
445 return has_been_buffered((address)src_addr);
446 }
447
448 address get_buffered_addr(address src_addr) const;
449 template <typename T> T get_buffered_addr(T src_addr) const {
450 CDS_ONLY(return (T)get_buffered_addr((address)src_addr);)
451 NOT_CDS(return nullptr;)
452 }
453
454 address get_source_addr(address buffered_addr) const;
455 template <typename T> T get_source_addr(T buffered_addr) const {
456 return (T)get_source_addr((address)buffered_addr);
457 }
458
459 // All klasses and symbols that will be copied into the archive
460 GrowableArray<Klass*>* klasses() const { return _klasses; }
461 GrowableArray<Symbol*>* symbols() const { return _symbols; }
462
463 static bool is_active() {
464 CDS_ONLY(return (_current != nullptr));
465 NOT_CDS(return false;)
466 }
467
468 static ArchiveBuilder* current() {
469 assert(_current != nullptr, "ArchiveBuilder must be active");
470 return _current;
471 }
472
473 static DumpAllocStats* alloc_stats() {
474 return &(current()->_alloc_stats);
475 }
476
477 static CompactHashtableStats* symbol_stats() {
478 return alloc_stats()->symbol_stats();
479 }
480
481 static CompactHashtableStats* string_stats() {
482 return alloc_stats()->string_stats();
483 }
484
485 narrowKlass get_requested_narrow_klass(Klass* k);
486
487 static Klass* get_buffered_klass(Klass* src_klass) {
488 Klass* klass = (Klass*)current()->get_buffered_addr((address)src_klass);
489 assert(klass != nullptr && klass->is_klass(), "must be");
490 return klass;
491 }
492
493 static Symbol* get_buffered_symbol(Symbol* src_symbol) {
494 return (Symbol*)current()->get_buffered_addr((address)src_symbol);
495 }
496
497 void print_stats();
498 void report_out_of_space(const char* name, size_t needed_bytes);
499
500 #ifdef _LP64
501 // The CDS archive contains pre-computed narrow Klass IDs. It carries them in the headers of
502 // archived heap objects. With +UseCompactObjectHeaders, it also carries them in prototypes
503 // in Klass.
504 // When generating the archive, these narrow Klass IDs are computed using the following scheme:
505 // 1) The future encoding base is assumed to point to the first address of the generated mapping.
506 // That means that at runtime, the narrow Klass encoding must be set up with base pointing to
507 // the start address of the mapped CDS metadata archive (wherever that may be). This precludes
508 // zero-based encoding.
509 // 2) The shift must be large enough to result in an encoding range that covers the future assumed
510 // runtime Klass range. That future Klass range will contain both the CDS metadata archive and
511 // the future runtime class space. Since we do not know the size of the future class space, we
512 // need to chose an encoding base/shift combination that will result in a "large enough" size.
513 // The details depend on whether we use compact object headers or legacy object headers.
514 // In Legacy Mode, a narrow Klass ID is 32 bit. This gives us an encoding range size of 4G even
515 // with shift = 0, which is all we need. Therefore, we use a shift=0 for pre-calculating the
516 // narrow Klass IDs.
517 // TinyClassPointer Mode:
518 // We use the highest possible shift value to maximize the encoding range size.
519 static int precomputed_narrow_klass_shift();
520 #endif // _LP64
521
522 };
523
524 #endif // SHARE_CDS_ARCHIVEBUILDER_HPP