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