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.
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5 * This code is free software; you can redistribute it and/or modify it
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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13 * accompanied this code).
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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/hashTable.hpp"
40 #include "utilities/resizableHashTable.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 friend class AOTMapLogger;
97
98 protected:
99 DumpRegion* _current_dump_region;
100 address _buffer_bottom; // for writing the contents of rw/ro regions
101
102 // These are the addresses where we will request the static and dynamic archives to be
103 // mapped at run time. If the request fails (due to ASLR), we will map the archives at
104 // os-selected addresses.
105 address _requested_static_archive_bottom; // This is determined solely by the value of
106 // SharedBaseAddress during -Xshare:dump.
107 address _requested_static_archive_top;
108 address _requested_dynamic_archive_bottom; // Used only during dynamic dump. It's placed
109 // immediately above _requested_static_archive_top.
110 address _requested_dynamic_archive_top;
111
112 // (Used only during dynamic dump) where the static archive is actually mapped. This
113 // may be different than _requested_static_archive_{bottom,top} due to ASLR
114 address _mapped_static_archive_bottom;
115 address _mapped_static_archive_top;
116
117 intx _buffer_to_requested_delta;
118
119 DumpRegion* current_dump_region() const { return _current_dump_region; }
120
121 public:
122 enum FollowMode {
123 make_a_copy, point_to_it, set_to_null
124 };
125
126 private:
127 class SourceObjInfo {
128 uintx _ptrmap_start; // The bit-offset of the start of this object (inclusive)
129 uintx _ptrmap_end; // The bit-offset of the end of this object (exclusive)
130 bool _read_only;
131 bool _has_embedded_pointer;
132 FollowMode _follow_mode;
133 int _size_in_bytes;
134 int _id; // Each object has a unique serial ID, starting from zero. The ID is assigned
135 // when the object is added into _source_objs.
136 MetaspaceObj::Type _msotype;
137 address _source_addr; // The source object to be copied.
138 address _buffered_addr; // The copy of this object insider the buffer.
139 public:
140 SourceObjInfo(MetaspaceClosure::Ref* ref, bool read_only, FollowMode follow_mode) :
141 _ptrmap_start(0), _ptrmap_end(0), _read_only(read_only), _has_embedded_pointer(false), _follow_mode(follow_mode),
142 _size_in_bytes(ref->size() * BytesPerWord), _id(0), _msotype(ref->msotype()),
143 _source_addr(ref->obj()) {
144 if (follow_mode == point_to_it) {
145 _buffered_addr = ref->obj();
146 } else {
147 _buffered_addr = nullptr;
148 }
149 }
150
151 // This constructor is only used for regenerated objects (created by LambdaFormInvokers, etc).
152 // src = address of a Method or InstanceKlass that has been regenerated.
153 // renegerated_obj_info = info for the regenerated version of src.
154 SourceObjInfo(address src, SourceObjInfo* renegerated_obj_info) :
155 _ptrmap_start(0), _ptrmap_end(0), _read_only(false),
156 _follow_mode(renegerated_obj_info->_follow_mode),
157 _size_in_bytes(0), _msotype(renegerated_obj_info->_msotype),
158 _source_addr(src), _buffered_addr(renegerated_obj_info->_buffered_addr) {}
159
160 bool should_copy() const { return _follow_mode == make_a_copy; }
161 void set_buffered_addr(address addr) {
162 assert(should_copy(), "must be");
163 assert(_buffered_addr == nullptr, "cannot be copied twice");
164 assert(addr != nullptr, "must be a valid copy");
165 _buffered_addr = addr;
166 }
167 void set_ptrmap_start(uintx v) { _ptrmap_start = v; }
168 void set_ptrmap_end(uintx v) { _ptrmap_end = v; }
169 uintx ptrmap_start() const { return _ptrmap_start; } // inclusive
170 uintx ptrmap_end() const { return _ptrmap_end; } // exclusive
171 bool read_only() const { return _read_only; }
172 bool has_embedded_pointer() const { return _has_embedded_pointer; }
173 void set_has_embedded_pointer() { _has_embedded_pointer = true; }
174 int size_in_bytes() const { return _size_in_bytes; }
175 int id() const { return _id; }
176 void set_id(int i) { _id = i; }
177 address source_addr() const { return _source_addr; }
178 address buffered_addr() const {
179 if (_follow_mode != set_to_null) {
180 assert(_buffered_addr != nullptr, "must be initialized");
181 }
182 return _buffered_addr;
183 }
184 MetaspaceObj::Type msotype() const { return _msotype; }
185 FollowMode follow_mode() const { return _follow_mode; }
186 };
187
188 class SourceObjList {
189 uintx _total_bytes;
190 GrowableArray<SourceObjInfo*>* _objs; // Source objects to be archived
191 CHeapBitMap _ptrmap; // Marks the addresses of the pointer fields
192 // in the source objects
193 public:
194 SourceObjList();
195 ~SourceObjList();
196
197 GrowableArray<SourceObjInfo*>* objs() const { return _objs; }
198
199 void append(SourceObjInfo* src_info);
200 void remember_embedded_pointer(SourceObjInfo* pointing_obj, MetaspaceClosure::Ref* ref);
201 void relocate(int i, ArchiveBuilder* builder);
202
203 // convenience accessor
204 SourceObjInfo* at(int i) const { return objs()->at(i); }
205 };
206
207 static const int INITIAL_TABLE_SIZE = 15889;
208 static const int MAX_TABLE_SIZE = 1000000;
209
210 ReservedSpace _shared_rs;
211 VirtualSpace _shared_vs;
212
213 // The "pz" region is used only during static dumps to reserve an unused space between SharedBaseAddress and
214 // the bottom of the rw region. During runtime, this space will be filled with a reserved area that disallows
215 // read/write/exec, so we can track for bad CompressedKlassPointers encoding.
216 // Note: this region does NOT exist in the cds archive.
217 DumpRegion _pz_region;
218
219 DumpRegion _rw_region;
220 DumpRegion _ro_region;
221 DumpRegion _ac_region; // AOT code
222
223 // Combined bitmap to track pointers in both RW and RO regions. This is updated
224 // as objects are copied into RW and RO.
225 CHeapBitMap _ptrmap;
226
227 // _ptrmap is split into these two bitmaps which are written into the archive.
228 CHeapBitMap _rw_ptrmap; // marks pointers in the RW region
229 CHeapBitMap _ro_ptrmap; // marks pointers in the RO region
230
231 SourceObjList _rw_src_objs; // objs to put in rw region
232 SourceObjList _ro_src_objs; // objs to put in ro region
233 ResizeableHashTable<address, SourceObjInfo, AnyObj::C_HEAP, mtClassShared> _src_obj_table;
234 ResizeableHashTable<address, address, AnyObj::C_HEAP, mtClassShared> _buffered_to_src_table;
235 GrowableArray<Klass*>* _klasses;
236 GrowableArray<Symbol*>* _symbols;
237 unsigned int _entropy_seed;
238
239 // statistics
240 DumpAllocStats _alloc_stats;
241 size_t _total_heap_region_size;
242 struct {
243 size_t _num_ptrs;
244 size_t _num_tagged_ptrs;
245 size_t _num_nulled_ptrs;
246 } _relocated_ptr_info;
247
248 void print_region_stats(FileMapInfo *map_info, ArchiveHeapInfo* heap_info);
249 void print_bitmap_region_stats(size_t size, size_t total_size);
250 void print_heap_region_stats(ArchiveHeapInfo* heap_info, size_t total_size);
251
252 // For global access.
253 static ArchiveBuilder* _current;
254
255 public:
256 // Use this when you allocate space outside of ArchiveBuilder::dump_{rw,ro}_region.
257 // These are usually for misc tables that are allocated in the RO space.
258 class OtherROAllocMark {
259 char* _oldtop;
260 public:
261 OtherROAllocMark() {
262 _oldtop = _current->_ro_region.top();
263 }
264 ~OtherROAllocMark();
265 };
266
267 void count_relocated_pointer(bool tagged, bool nulled);
268
269 private:
270 FollowMode get_follow_mode(MetaspaceClosure::Ref *ref);
271
272 void iterate_sorted_roots(MetaspaceClosure* it);
273 void sort_klasses();
274 static int compare_symbols_by_address(Symbol** a, Symbol** b);
275 static int compare_klass_by_name(Klass** a, Klass** b);
276
277 void make_shallow_copies(DumpRegion *dump_region, const SourceObjList* src_objs);
278 void make_shallow_copy(DumpRegion *dump_region, SourceObjInfo* src_info);
279
280 void relocate_embedded_pointers(SourceObjList* src_objs);
281
282 bool is_excluded(Klass* k);
283 void clean_up_src_obj_table();
284
285 protected:
286 virtual void iterate_roots(MetaspaceClosure* it) = 0;
287 void start_dump_region(DumpRegion* next);
288
289 public:
290 address reserve_buffer();
291
292 address buffer_bottom() const { return _buffer_bottom; }
293 address buffer_top() const { return (address)current_dump_region()->top(); }
294 address requested_static_archive_bottom() const { return _requested_static_archive_bottom; }
295 address mapped_static_archive_bottom() const { return _mapped_static_archive_bottom; }
296 intx buffer_to_requested_delta() const { return _buffer_to_requested_delta; }
297
298 bool is_in_buffer_space(address p) const {
299 return (buffer_bottom() != nullptr && buffer_bottom() <= p && p < buffer_top());
300 }
301
302 template <typename T> bool is_in_requested_static_archive(T p) const {
303 return _requested_static_archive_bottom <= (address)p && (address)p < _requested_static_archive_top;
304 }
305
306 template <typename T> bool is_in_mapped_static_archive(T p) const {
307 return _mapped_static_archive_bottom <= (address)p && (address)p < _mapped_static_archive_top;
308 }
309
310 template <typename T> bool is_in_buffer_space(T obj) const {
311 return is_in_buffer_space(address(obj));
312 }
313
314 template <typename T> T to_requested(T obj) const {
315 assert(is_in_buffer_space(obj), "must be");
316 return (T)(address(obj) + _buffer_to_requested_delta);
317 }
318
319 template <typename T> T requested_to_buffered(T obj) const {
320 T b = (T)(address(obj) - _buffer_to_requested_delta);
321 assert(is_in_buffer_space(b), "must be");
322 return b;
323 }
324
325 static intx get_buffer_to_requested_delta() {
326 return current()->buffer_to_requested_delta();
327 }
328
329 inline static u4 to_offset_u4(uintx offset) {
330 guarantee(offset <= MAX_SHARED_DELTA, "must be 32-bit offset " INTPTR_FORMAT, offset);
331 return (u4)offset;
332 }
333
334 public:
335 static const uintx MAX_SHARED_DELTA = ArchiveUtils::MAX_SHARED_DELTA;;
336
337 // The address p points to an object inside the output buffer. When the archive is mapped
338 // at the requested address, what's the offset of this object from _requested_static_archive_bottom?
339 uintx buffer_to_offset(address p) const;
340
341 // Same as buffer_to_offset, except that the address p points to either (a) an object
342 // inside the output buffer, or (b), an object in the currently mapped static archive.
343 uintx any_to_offset(address p) const;
344
345 // The reverse of buffer_to_offset()
346 address offset_to_buffered_address(u4 offset) const;
347
348 template <typename T>
349 u4 buffer_to_offset_u4(T p) const {
350 uintx offset = buffer_to_offset((address)p);
351 return to_offset_u4(offset);
352 }
353
354 template <typename T>
355 u4 any_to_offset_u4(T p) const {
356 assert(p != nullptr, "must not be null");
357 uintx offset = any_to_offset((address)p);
358 return to_offset_u4(offset);
359 }
360
361 template <typename T>
362 u4 any_or_null_to_offset_u4(T p) const {
363 if (p == nullptr) {
364 return 0;
365 } else {
366 return any_to_offset_u4<T>(p);
367 }
368 }
369
370 template <typename T>
371 T offset_to_buffered(u4 offset) const {
372 return (T)offset_to_buffered_address(offset);
373 }
374
375 public:
376 ArchiveBuilder();
377 ~ArchiveBuilder();
378
379 int entropy();
380 void gather_klasses_and_symbols();
381 void gather_source_objs();
382 bool gather_klass_and_symbol(MetaspaceClosure::Ref* ref, bool read_only);
383 bool gather_one_source_obj(MetaspaceClosure::Ref* ref, bool read_only);
384 void remember_embedded_pointer_in_enclosing_obj(MetaspaceClosure::Ref* ref);
385 static void serialize_dynamic_archivable_items(SerializeClosure* soc);
386
387 DumpRegion* pz_region() { return &_pz_region; }
388 DumpRegion* rw_region() { return &_rw_region; }
389 DumpRegion* ro_region() { return &_ro_region; }
390 DumpRegion* ac_region() { return &_ac_region; }
391
392 static char* rw_region_alloc(size_t num_bytes) {
393 return current()->rw_region()->allocate(num_bytes);
394 }
395 static char* ro_region_alloc(size_t num_bytes) {
396 return current()->ro_region()->allocate(num_bytes);
397 }
398 static char* ac_region_alloc(size_t num_bytes) {
399 return current()->ac_region()->allocate(num_bytes);
400 }
401
402 void start_ac_region();
403 void end_ac_region();
404
405 template <typename T>
406 static Array<T>* new_ro_array(int length) {
407 size_t byte_size = Array<T>::byte_sizeof(length, sizeof(T));
408 Array<T>* array = (Array<T>*)ro_region_alloc(byte_size);
409 array->initialize(length);
410 return array;
411 }
412
413 template <typename T>
414 static Array<T>* new_rw_array(int length) {
415 size_t byte_size = Array<T>::byte_sizeof(length, sizeof(T));
416 Array<T>* array = (Array<T>*)rw_region_alloc(byte_size);
417 array->initialize(length);
418 return array;
419 }
420
421 template <typename T>
422 static size_t ro_array_bytesize(int length) {
423 size_t byte_size = Array<T>::byte_sizeof(length, sizeof(T));
424 return align_up(byte_size, SharedSpaceObjectAlignment);
425 }
426
427 char* ro_strdup(const char* s);
428
429 static int compare_src_objs(SourceObjInfo** a, SourceObjInfo** b);
430 void sort_metadata_objs();
431 void dump_rw_metadata();
432 void dump_ro_metadata();
433 void relocate_metaspaceobj_embedded_pointers();
434 void record_regenerated_object(address orig_src_obj, address regen_src_obj);
435 void make_klasses_shareable();
436 void make_training_data_shareable();
437 void relocate_to_requested();
438 void write_archive(FileMapInfo* mapinfo, ArchiveHeapInfo* heap_info);
439 void write_region(FileMapInfo* mapinfo, int region_idx, DumpRegion* dump_region,
440 bool read_only, bool allow_exec);
441
442 void write_pointer_in_buffer(address* ptr_location, address src_addr);
443 template <typename T> void write_pointer_in_buffer(T* ptr_location, T src_addr) {
444 write_pointer_in_buffer((address*)ptr_location, (address)src_addr);
445 }
446
447 void mark_and_relocate_to_buffered_addr(address* ptr_location);
448 template <typename T> void mark_and_relocate_to_buffered_addr(T ptr_location) {
449 mark_and_relocate_to_buffered_addr((address*)ptr_location);
450 }
451
452 bool has_been_archived(address src_addr) const;
453 template <typename T> bool has_been_archived(T src_addr) const {
454 return has_been_archived((address)src_addr);
455 }
456
457 address get_buffered_addr(address src_addr) const;
458 template <typename T> T get_buffered_addr(T src_addr) const {
459 CDS_ONLY(return (T)get_buffered_addr((address)src_addr);)
460 NOT_CDS(return nullptr;)
461 }
462
463 address get_source_addr(address buffered_addr) const;
464 template <typename T> T get_source_addr(T buffered_addr) const {
465 return (T)get_source_addr((address)buffered_addr);
466 }
467
468 // All klasses and symbols that will be copied into the archive
469 GrowableArray<Klass*>* klasses() const { return _klasses; }
470 GrowableArray<Symbol*>* symbols() const { return _symbols; }
471
472 static bool is_active() {
473 CDS_ONLY(return (_current != nullptr));
474 NOT_CDS(return false;)
475 }
476
477 static ArchiveBuilder* current() {
478 assert(_current != nullptr, "ArchiveBuilder must be active");
479 return _current;
480 }
481
482 static DumpAllocStats* alloc_stats() {
483 return &(current()->_alloc_stats);
484 }
485
486 static CompactHashtableStats* symbol_stats() {
487 return alloc_stats()->symbol_stats();
488 }
489
490 static CompactHashtableStats* string_stats() {
491 return alloc_stats()->string_stats();
492 }
493
494 narrowKlass get_requested_narrow_klass(Klass* k);
495
496 static Klass* get_buffered_klass(Klass* src_klass) {
497 Klass* klass = (Klass*)current()->get_buffered_addr((address)src_klass);
498 assert(klass != nullptr && klass->is_klass(), "must be");
499 return klass;
500 }
501
502 static Symbol* get_buffered_symbol(Symbol* src_symbol) {
503 return (Symbol*)current()->get_buffered_addr((address)src_symbol);
504 }
505
506 void print_stats();
507 void report_out_of_space(const char* name, size_t needed_bytes);
508
509 #ifdef _LP64
510 // The CDS archive contains pre-computed narrow Klass IDs. It carries them in the headers of
511 // archived heap objects. With +UseCompactObjectHeaders, it also carries them in prototypes
512 // in Klass.
513 // When generating the archive, these narrow Klass IDs are computed using the following scheme:
514 // 1) The future encoding base is assumed to point to the first address of the generated mapping.
515 // That means that at runtime, the narrow Klass encoding must be set up with base pointing to
516 // the start address of the mapped CDS metadata archive (wherever that may be). This precludes
517 // zero-based encoding.
518 // 2) The shift must be large enough to result in an encoding range that covers the future assumed
519 // runtime Klass range. That future Klass range will contain both the CDS metadata archive and
520 // the future runtime class space. Since we do not know the size of the future class space, we
521 // need to chose an encoding base/shift combination that will result in a "large enough" size.
522 // The details depend on whether we use compact object headers or legacy object headers.
523 // In Legacy Mode, a narrow Klass ID is 32 bit. This gives us an encoding range size of 4G even
524 // with shift = 0, which is all we need. Therefore, we use a shift=0 for pre-calculating the
525 // narrow Klass IDs.
526 // TinyClassPointer Mode:
527 // We use the highest possible shift value to maximize the encoding range size.
528 static int precomputed_narrow_klass_shift();
529 #endif // _LP64
530
531 };
532
533 #endif // SHARE_CDS_ARCHIVEBUILDER_HPP