1 /*
2 * Copyright (c) 2012, 2014, 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 "classfile/dictionary.hpp"
27 #include "classfile/loaderConstraints.hpp"
28 #include "classfile/placeholders.hpp"
29 #include "classfile/symbolTable.hpp"
30 #include "classfile/systemDictionary.hpp"
31 #include "code/codeCache.hpp"
32 #include "memory/filemap.hpp"
33 #include "memory/gcLocker.hpp"
34 #include "memory/metaspace.hpp"
35 #include "memory/metaspaceShared.hpp"
36 #include "oops/objArrayOop.hpp"
37 #include "oops/oop.inline.hpp"
38 #include "runtime/os.hpp"
39 #include "runtime/signature.hpp"
40 #include "runtime/vm_operations.hpp"
41 #include "runtime/vmThread.hpp"
42 #include "utilities/hashtable.inline.hpp"
43
44 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
45
46 int MetaspaceShared::_max_alignment = 0;
47
48 ReservedSpace* MetaspaceShared::_shared_rs = NULL;
49
50 // Read/write a data stream for restoring/preserving metadata pointers and
51 // miscellaneous data from/to the shared archive file.
52
53 void MetaspaceShared::serialize(SerializeClosure* soc) {
54 int tag = 0;
55 soc->do_tag(--tag);
56
57 // Verify the sizes of various metadata in the system.
58 soc->do_tag(sizeof(Method));
59 soc->do_tag(sizeof(ConstMethod));
60 soc->do_tag(arrayOopDesc::base_offset_in_bytes(T_BYTE));
61 soc->do_tag(sizeof(ConstantPool));
62 soc->do_tag(sizeof(ConstantPoolCache));
63 soc->do_tag(objArrayOopDesc::base_offset_in_bytes());
64 soc->do_tag(typeArrayOopDesc::base_offset_in_bytes(T_BYTE));
65 soc->do_tag(sizeof(Symbol));
66
67 // Dump/restore miscellaneous metadata.
68 Universe::serialize(soc, true);
69 soc->do_tag(--tag);
70
71 // Dump/restore references to commonly used names and signatures.
72 vmSymbols::serialize(soc);
73 soc->do_tag(--tag);
74
75 soc->do_tag(666);
76 }
77
78
79 // CDS code for dumping shared archive.
80
81 // Global object for holding classes that have been loaded. Since this
82 // is run at a safepoint just before exit, this is the entire set of classes.
83 static GrowableArray<Klass*>* _global_klass_objects;
84 static void collect_classes(Klass* k) {
85 _global_klass_objects->append_if_missing(k);
86 if (k->oop_is_instance()) {
87 // Add in the array classes too
88 InstanceKlass* ik = InstanceKlass::cast(k);
89 ik->array_klasses_do(collect_classes);
90 }
91 }
92
93 static void remove_unshareable_in_classes() {
94 for (int i = 0; i < _global_klass_objects->length(); i++) {
95 Klass* k = _global_klass_objects->at(i);
96 k->remove_unshareable_info();
97 }
98 }
99
100 // Walk all methods in the class list and assign a fingerprint.
101 // so that this part of the ConstMethod* is read only.
102 static void calculate_fingerprints() {
103 for (int i = 0; i < _global_klass_objects->length(); i++) {
104 Klass* k = _global_klass_objects->at(i);
105 if (k->oop_is_instance()) {
106 InstanceKlass* ik = InstanceKlass::cast(k);
107 for (int i = 0; i < ik->methods()->length(); i++) {
108 Method* m = ik->methods()->at(i);
109 Fingerprinter fp(m);
110 // The side effect of this call sets method's fingerprint field.
111 fp.fingerprint();
112 }
113 }
114 }
115 }
116
117 // Patch C++ vtable pointer in metadata.
118
119 // Klass and other metadata objects contain references to c++ vtables in the
120 // JVM library.
121 // Fix them to point to our constructed vtables. However, don't iterate
122 // across the space while doing this, as that causes the vtables to be
123 // patched, undoing our useful work. Instead, iterate to make a list,
124 // then use the list to do the fixing.
125 //
126 // Our constructed vtables:
127 // Dump time:
128 // 1. init_self_patching_vtbl_list: table of pointers to current virtual method addrs
129 // 2. generate_vtable_methods: create jump table, appended to above vtbl_list
130 // 3. patch_klass_vtables: for Klass list, patch the vtable entry in klass and
131 // associated metadata to point to jump table rather than to current vtbl
132 // Table layout: NOTE FIXED SIZE
133 // 1. vtbl pointers
134 // 2. #Klass X #virtual methods per Klass
135 // 1 entry for each, in the order:
136 // Klass1:method1 entry, Klass1:method2 entry, ... Klass1:method<num_virtuals> entry
137 // Klass2:method1 entry, Klass2:method2 entry, ... Klass2:method<num_virtuals> entry
138 // ...
139 // Klass<vtbl_list_size>:method1 entry, Klass<vtbl_list_size>:method2 entry,
140 // ... Klass<vtbl_list_size>:method<num_virtuals> entry
141 // Sample entry: (Sparc):
142 // save(sp, -256, sp)
143 // ba,pt common_code
144 // mov XXX, %L0 %L0 gets: Klass index <<8 + method index (note: max method index 255)
145 //
146 // Restore time:
147 // 1. initialize_shared_space: reserve space for table
148 // 2. init_self_patching_vtbl_list: update pointers to NEW virtual method addrs in text
149 //
150 // Execution time:
151 // First virtual method call for any object of these metadata types:
152 // 1. object->klass
153 // 2. vtable entry for that klass points to the jump table entries
154 // 3. branches to common_code with %O0/klass, %L0: Klass index <<8 + method index
155 // 4. common_code:
156 // Get address of new vtbl pointer for this Klass from updated table
157 // Update new vtbl pointer in the Klass: future virtual calls go direct
158 // Jump to method, using new vtbl pointer and method index
159
160
161 static void* find_matching_vtbl_ptr(void** vtbl_list, void* new_vtable_start, void* obj) {
162 void* old_vtbl_ptr = *(void**)obj;
163 for (int i = 0; i < MetaspaceShared::vtbl_list_size; i++) {
164 if (vtbl_list[i] == old_vtbl_ptr) {
165 return (void**)new_vtable_start + i * MetaspaceShared::num_virtuals;
166 }
167 }
168 ShouldNotReachHere();
169 return NULL;
170 }
171
172 // Assumes the vtable is in first slot in object.
173 static void patch_klass_vtables(void** vtbl_list, void* new_vtable_start) {
174 int n = _global_klass_objects->length();
175 for (int i = 0; i < n; i++) {
176 Klass* obj = _global_klass_objects->at(i);
177 // Note oop_is_instance() is a virtual call. After patching vtables
178 // all virtual calls on the dummy vtables will restore the original!
179 if (obj->oop_is_instance()) {
180 InstanceKlass* ik = InstanceKlass::cast(obj);
181 *(void**)ik = find_matching_vtbl_ptr(vtbl_list, new_vtable_start, ik);
182 ConstantPool* cp = ik->constants();
183 *(void**)cp = find_matching_vtbl_ptr(vtbl_list, new_vtable_start, cp);
184 for (int j = 0; j < ik->methods()->length(); j++) {
185 Method* m = ik->methods()->at(j);
186 *(void**)m = find_matching_vtbl_ptr(vtbl_list, new_vtable_start, m);
187 }
188 } else {
189 // Array klasses
190 Klass* k = obj;
191 *(void**)k = find_matching_vtbl_ptr(vtbl_list, new_vtable_start, k);
192 }
193 }
194 }
195
196 // Closure for serializing initialization data out to a data area to be
197 // written to the shared file.
198
199 class WriteClosure : public SerializeClosure {
200 private:
201 intptr_t* top;
202 char* end;
203
204 inline void check_space() {
205 if ((char*)top + sizeof(intptr_t) > end) {
206 report_out_of_shared_space(SharedMiscData);
207 }
208 }
209
210 public:
211 WriteClosure(char* md_top, char* md_end) {
212 top = (intptr_t*)md_top;
213 end = md_end;
214 }
215
216 char* get_top() { return (char*)top; }
217
218 void do_ptr(void** p) {
219 check_space();
220 *top = (intptr_t)*p;
221 ++top;
222 }
223
224 void do_tag(int tag) {
225 check_space();
226 *top = (intptr_t)tag;
227 ++top;
228 }
229
230 void do_region(u_char* start, size_t size) {
231 if ((char*)top + size > end) {
232 report_out_of_shared_space(SharedMiscData);
233 }
234 assert((intptr_t)start % sizeof(intptr_t) == 0, "bad alignment");
235 assert(size % sizeof(intptr_t) == 0, "bad size");
236 do_tag((int)size);
237 while (size > 0) {
238 *top = *(intptr_t*)start;
239 ++top;
240 start += sizeof(intptr_t);
241 size -= sizeof(intptr_t);
242 }
243 }
244
245 bool reading() const { return false; }
246 };
247
248 // This is for dumping detailed statistics for the allocations
249 // in the shared spaces.
250 class DumpAllocClosure : public Metaspace::AllocRecordClosure {
251 public:
252
253 // Here's poor man's enum inheritance
254 #define SHAREDSPACE_OBJ_TYPES_DO(f) \
255 METASPACE_OBJ_TYPES_DO(f) \
256 f(SymbolHashentry) \
257 f(SymbolBuckets) \
258 f(Other)
259
260 #define SHAREDSPACE_OBJ_TYPE_DECLARE(name) name ## Type,
261 #define SHAREDSPACE_OBJ_TYPE_NAME_CASE(name) case name ## Type: return #name;
262
263 enum Type {
264 // Types are MetaspaceObj::ClassType, MetaspaceObj::SymbolType, etc
265 SHAREDSPACE_OBJ_TYPES_DO(SHAREDSPACE_OBJ_TYPE_DECLARE)
266 _number_of_types
267 };
268
269 static const char * type_name(Type type) {
270 switch(type) {
271 SHAREDSPACE_OBJ_TYPES_DO(SHAREDSPACE_OBJ_TYPE_NAME_CASE)
272 default:
273 ShouldNotReachHere();
274 return NULL;
275 }
276 }
277
278 public:
279 enum {
280 RO = 0,
281 RW = 1
282 };
283
284 int _counts[2][_number_of_types];
285 int _bytes [2][_number_of_types];
286 int _which;
287
288 DumpAllocClosure() {
289 memset(_counts, 0, sizeof(_counts));
290 memset(_bytes, 0, sizeof(_bytes));
291 };
292
293 void iterate_metaspace(Metaspace* space, int which) {
294 assert(which == RO || which == RW, "sanity");
295 _which = which;
296 space->iterate(this);
297 }
298
299 virtual void doit(address ptr, MetaspaceObj::Type type, int byte_size) {
300 assert(int(type) >= 0 && type < MetaspaceObj::_number_of_types, "sanity");
301 _counts[_which][type] ++;
302 _bytes [_which][type] += byte_size;
303 }
304
305 void dump_stats(int ro_all, int rw_all, int md_all, int mc_all);
306 };
307
308 void DumpAllocClosure::dump_stats(int ro_all, int rw_all, int md_all, int mc_all) {
309 rw_all += (md_all + mc_all); // md and mc are all mapped Read/Write
310 int other_bytes = md_all + mc_all;
311
312 // Calculate size of data that was not allocated by Metaspace::allocate()
313 int symbol_count = _counts[RO][MetaspaceObj::SymbolType];
314 int symhash_bytes = symbol_count * sizeof (HashtableEntry<Symbol*, mtSymbol>);
315 int symbuck_count = SymbolTable::the_table()->table_size();
316 int symbuck_bytes = symbuck_count * sizeof(HashtableBucket<mtSymbol>);
317
318 _counts[RW][SymbolHashentryType] = symbol_count;
319 _bytes [RW][SymbolHashentryType] = symhash_bytes;
320 other_bytes -= symhash_bytes;
321
322 _counts[RW][SymbolBucketsType] = symbuck_count;
323 _bytes [RW][SymbolBucketsType] = symbuck_bytes;
324 other_bytes -= symbuck_bytes;
325
326 // TODO: count things like dictionary, vtable, etc
327 _bytes[RW][OtherType] = other_bytes;
328
329 // prevent divide-by-zero
330 if (ro_all < 1) {
331 ro_all = 1;
332 }
333 if (rw_all < 1) {
334 rw_all = 1;
335 }
336
337 int all_ro_count = 0;
338 int all_ro_bytes = 0;
339 int all_rw_count = 0;
340 int all_rw_bytes = 0;
341
342 // To make fmt_stats be a syntactic constant (for format warnings), use #define.
343 #define fmt_stats "%-20s: %8d %10d %5.1f | %8d %10d %5.1f | %8d %10d %5.1f"
344 const char *sep = "--------------------+---------------------------+---------------------------+--------------------------";
345 const char *hdr = " ro_cnt ro_bytes % | rw_cnt rw_bytes % | all_cnt all_bytes %";
346
347 tty->print_cr("Detailed metadata info (rw includes md and mc):");
348 tty->print_cr("%s", hdr);
349 tty->print_cr("%s", sep);
350 for (int type = 0; type < int(_number_of_types); type ++) {
351 const char *name = type_name((Type)type);
352 int ro_count = _counts[RO][type];
353 int ro_bytes = _bytes [RO][type];
354 int rw_count = _counts[RW][type];
355 int rw_bytes = _bytes [RW][type];
356 int count = ro_count + rw_count;
357 int bytes = ro_bytes + rw_bytes;
358
359 double ro_perc = 100.0 * double(ro_bytes) / double(ro_all);
360 double rw_perc = 100.0 * double(rw_bytes) / double(rw_all);
361 double perc = 100.0 * double(bytes) / double(ro_all + rw_all);
362
363 tty->print_cr(fmt_stats, name,
364 ro_count, ro_bytes, ro_perc,
365 rw_count, rw_bytes, rw_perc,
366 count, bytes, perc);
367
368 all_ro_count += ro_count;
369 all_ro_bytes += ro_bytes;
370 all_rw_count += rw_count;
371 all_rw_bytes += rw_bytes;
372 }
373
374 int all_count = all_ro_count + all_rw_count;
375 int all_bytes = all_ro_bytes + all_rw_bytes;
376
377 double all_ro_perc = 100.0 * double(all_ro_bytes) / double(ro_all);
378 double all_rw_perc = 100.0 * double(all_rw_bytes) / double(rw_all);
379 double all_perc = 100.0 * double(all_bytes) / double(ro_all + rw_all);
380
381 tty->print_cr("%s", sep);
382 tty->print_cr(fmt_stats, "Total",
383 all_ro_count, all_ro_bytes, all_ro_perc,
384 all_rw_count, all_rw_bytes, all_rw_perc,
385 all_count, all_bytes, all_perc);
386
387 assert(all_ro_bytes == ro_all, "everything should have been counted");
388 assert(all_rw_bytes == rw_all, "everything should have been counted");
389 #undef fmt_stats
390 }
391
392 // Populate the shared space.
393
394 class VM_PopulateDumpSharedSpace: public VM_Operation {
395 private:
396 ClassLoaderData* _loader_data;
397 GrowableArray<Klass*> *_class_promote_order;
398 VirtualSpace _md_vs;
399 VirtualSpace _mc_vs;
400
401 public:
402 VM_PopulateDumpSharedSpace(ClassLoaderData* loader_data,
403 GrowableArray<Klass*> *class_promote_order) :
404 _loader_data(loader_data) {
405
406 // Split up and initialize the misc code and data spaces
407 ReservedSpace* shared_rs = MetaspaceShared::shared_rs();
408 int metadata_size = SharedReadOnlySize+SharedReadWriteSize;
409 ReservedSpace shared_ro_rw = shared_rs->first_part(metadata_size);
410 ReservedSpace misc_section = shared_rs->last_part(metadata_size);
411
412 // Now split into misc sections.
413 ReservedSpace md_rs = misc_section.first_part(SharedMiscDataSize);
414 ReservedSpace mc_rs = misc_section.last_part(SharedMiscDataSize);
415 _md_vs.initialize(md_rs, SharedMiscDataSize);
416 _mc_vs.initialize(mc_rs, SharedMiscCodeSize);
417 _class_promote_order = class_promote_order;
418 }
419
420 VMOp_Type type() const { return VMOp_PopulateDumpSharedSpace; }
421 void doit(); // outline because gdb sucks
422 }; // class VM_PopulateDumpSharedSpace
423
424
425 void VM_PopulateDumpSharedSpace::doit() {
426 Thread* THREAD = VMThread::vm_thread();
427 NOT_PRODUCT(SystemDictionary::verify();)
428 // The following guarantee is meant to ensure that no loader constraints
429 // exist yet, since the constraints table is not shared. This becomes
430 // more important now that we don't re-initialize vtables/itables for
431 // shared classes at runtime, where constraints were previously created.
432 guarantee(SystemDictionary::constraints()->number_of_entries() == 0,
433 "loader constraints are not saved");
434 guarantee(SystemDictionary::placeholders()->number_of_entries() == 0,
435 "placeholders are not saved");
436 // Revisit and implement this if we prelink method handle call sites:
437 guarantee(SystemDictionary::invoke_method_table() == NULL ||
438 SystemDictionary::invoke_method_table()->number_of_entries() == 0,
439 "invoke method table is not saved");
440
441 // At this point, many classes have been loaded.
442 // Gather systemDictionary classes in a global array and do everything to
443 // that so we don't have to walk the SystemDictionary again.
444 _global_klass_objects = new GrowableArray<Klass*>(1000);
445 Universe::basic_type_classes_do(collect_classes);
446 SystemDictionary::classes_do(collect_classes);
447
448 tty->print_cr("Number of classes %d", _global_klass_objects->length());
449
450 // Update all the fingerprints in the shared methods.
451 tty->print("Calculating fingerprints ... ");
452 calculate_fingerprints();
453 tty->print_cr("done. ");
454
455 // Remove all references outside the metadata
456 tty->print("Removing unshareable information ... ");
457 remove_unshareable_in_classes();
458 tty->print_cr("done. ");
459
460 // Set up the share data and shared code segments.
461 char* md_low = _md_vs.low();
462 char* md_top = md_low;
463 char* md_end = _md_vs.high();
464 char* mc_low = _mc_vs.low();
465 char* mc_top = mc_low;
466 char* mc_end = _mc_vs.high();
467
468 // Reserve space for the list of Klass*s whose vtables are used
469 // for patching others as needed.
470
471 void** vtbl_list = (void**)md_top;
472 int vtbl_list_size = MetaspaceShared::vtbl_list_size;
473 Universe::init_self_patching_vtbl_list(vtbl_list, vtbl_list_size);
474
475 md_top += vtbl_list_size * sizeof(void*);
476 void* vtable = md_top;
477
478 // Reserve space for a new dummy vtable for klass objects in the
479 // heap. Generate self-patching vtable entries.
480
481 MetaspaceShared::generate_vtable_methods(vtbl_list, &vtable,
482 &md_top, md_end,
483 &mc_top, mc_end);
484
485 // Reorder the system dictionary. (Moving the symbols affects
486 // how the hash table indices are calculated.)
487 // Not doing this either.
488
489 SystemDictionary::reorder_dictionary();
490
491 NOT_PRODUCT(SystemDictionary::verify();)
492
493 // Copy the the symbol table, and the system dictionary to the shared
494 // space in usable form. Copy the hashtable
495 // buckets first [read-write], then copy the linked lists of entries
496 // [read-only].
497
498 SymbolTable::reverse(md_top);
499 NOT_PRODUCT(SymbolTable::verify());
500 SymbolTable::copy_buckets(&md_top, md_end);
501
502 SystemDictionary::reverse();
503 SystemDictionary::copy_buckets(&md_top, md_end);
504
505 ClassLoader::verify();
506 ClassLoader::copy_package_info_buckets(&md_top, md_end);
507 ClassLoader::verify();
508
509 SymbolTable::copy_table(&md_top, md_end);
510 SystemDictionary::copy_table(&md_top, md_end);
511 ClassLoader::verify();
512 ClassLoader::copy_package_info_table(&md_top, md_end);
513 ClassLoader::verify();
514
515 // Write the other data to the output array.
516 WriteClosure wc(md_top, md_end);
517 MetaspaceShared::serialize(&wc);
518 md_top = wc.get_top();
519
520 // Print shared spaces all the time
521 // To make fmt_space be a syntactic constant (for format warnings), use #define.
522 #define fmt_space "%s space: %9d [ %4.1f%% of total] out of %9d bytes [%4.1f%% used] at " INTPTR_FORMAT
523 Metaspace* ro_space = _loader_data->ro_metaspace();
524 Metaspace* rw_space = _loader_data->rw_metaspace();
525
526 // Allocated size of each space (may not be all occupied)
527 const size_t ro_alloced = ro_space->capacity_bytes_slow(Metaspace::NonClassType);
528 const size_t rw_alloced = rw_space->capacity_bytes_slow(Metaspace::NonClassType);
529 const size_t md_alloced = md_end-md_low;
530 const size_t mc_alloced = mc_end-mc_low;
531 const size_t total_alloced = ro_alloced + rw_alloced + md_alloced + mc_alloced;
532
533 // Occupied size of each space.
534 const size_t ro_bytes = ro_space->used_bytes_slow(Metaspace::NonClassType);
535 const size_t rw_bytes = rw_space->used_bytes_slow(Metaspace::NonClassType);
536 const size_t md_bytes = size_t(md_top - md_low);
537 const size_t mc_bytes = size_t(mc_top - mc_low);
538
539 // Percent of total size
540 const size_t total_bytes = ro_bytes + rw_bytes + md_bytes + mc_bytes;
541 const double ro_t_perc = ro_bytes / double(total_bytes) * 100.0;
542 const double rw_t_perc = rw_bytes / double(total_bytes) * 100.0;
543 const double md_t_perc = md_bytes / double(total_bytes) * 100.0;
544 const double mc_t_perc = mc_bytes / double(total_bytes) * 100.0;
545
546 // Percent of fullness of each space
547 const double ro_u_perc = ro_bytes / double(ro_alloced) * 100.0;
548 const double rw_u_perc = rw_bytes / double(rw_alloced) * 100.0;
549 const double md_u_perc = md_bytes / double(md_alloced) * 100.0;
550 const double mc_u_perc = mc_bytes / double(mc_alloced) * 100.0;
551 const double total_u_perc = total_bytes / double(total_alloced) * 100.0;
552
553 tty->print_cr(fmt_space, "ro", ro_bytes, ro_t_perc, ro_alloced, ro_u_perc, ro_space->bottom());
554 tty->print_cr(fmt_space, "rw", rw_bytes, rw_t_perc, rw_alloced, rw_u_perc, rw_space->bottom());
555 tty->print_cr(fmt_space, "md", md_bytes, md_t_perc, md_alloced, md_u_perc, md_low);
556 tty->print_cr(fmt_space, "mc", mc_bytes, mc_t_perc, mc_alloced, mc_u_perc, mc_low);
557 tty->print_cr("total : %9d [100.0%% of total] out of %9d bytes [%4.1f%% used]",
558 total_bytes, total_alloced, total_u_perc);
559
560 // Update the vtable pointers in all of the Klass objects in the
561 // heap. They should point to newly generated vtable.
562 patch_klass_vtables(vtbl_list, vtable);
563
564 // dunno what this is for.
565 char* saved_vtbl = (char*)os::malloc(vtbl_list_size * sizeof(void*), mtClass);
566 memmove(saved_vtbl, vtbl_list, vtbl_list_size * sizeof(void*));
567 memset(vtbl_list, 0, vtbl_list_size * sizeof(void*));
568
569 // Create and write the archive file that maps the shared spaces.
570
571 FileMapInfo* mapinfo = new FileMapInfo();
572 mapinfo->populate_header(MetaspaceShared::max_alignment());
573
574 // Pass 1 - update file offsets in header.
575 mapinfo->write_header();
576 mapinfo->write_space(MetaspaceShared::ro, _loader_data->ro_metaspace(), true);
577 mapinfo->write_space(MetaspaceShared::rw, _loader_data->rw_metaspace(), false);
578 mapinfo->write_region(MetaspaceShared::md, _md_vs.low(),
579 pointer_delta(md_top, _md_vs.low(), sizeof(char)),
580 SharedMiscDataSize,
581 false, false);
582 mapinfo->write_region(MetaspaceShared::mc, _mc_vs.low(),
583 pointer_delta(mc_top, _mc_vs.low(), sizeof(char)),
584 SharedMiscCodeSize,
585 true, true);
586
587 // Pass 2 - write data.
588 mapinfo->open_for_write();
589 mapinfo->write_header();
590 mapinfo->write_space(MetaspaceShared::ro, _loader_data->ro_metaspace(), true);
591 mapinfo->write_space(MetaspaceShared::rw, _loader_data->rw_metaspace(), false);
592 mapinfo->write_region(MetaspaceShared::md, _md_vs.low(),
593 pointer_delta(md_top, _md_vs.low(), sizeof(char)),
594 SharedMiscDataSize,
595 false, false);
596 mapinfo->write_region(MetaspaceShared::mc, _mc_vs.low(),
597 pointer_delta(mc_top, _mc_vs.low(), sizeof(char)),
598 SharedMiscCodeSize,
599 true, true);
600 mapinfo->close();
601
602 memmove(vtbl_list, saved_vtbl, vtbl_list_size * sizeof(void*));
603
604 if (PrintSharedSpaces) {
605 DumpAllocClosure dac;
606 dac.iterate_metaspace(_loader_data->ro_metaspace(), DumpAllocClosure::RO);
607 dac.iterate_metaspace(_loader_data->rw_metaspace(), DumpAllocClosure::RW);
608
609 dac.dump_stats(int(ro_bytes), int(rw_bytes), int(md_bytes), int(mc_bytes));
610 }
611 #undef fmt_space
612 }
613
614 static void link_shared_classes(Klass* obj, TRAPS) {
615 Klass* k = obj;
616 if (k->oop_is_instance()) {
617 InstanceKlass* ik = (InstanceKlass*) k;
618 // Link the class to cause the bytecodes to be rewritten and the
619 // cpcache to be created.
620 if (ik->init_state() < InstanceKlass::linked) {
621 ik->link_class(THREAD);
622 guarantee(!HAS_PENDING_EXCEPTION, "exception in class rewriting");
623 }
624 }
625 }
626
627
628 // Support for a simple checksum of the contents of the class list
629 // file to prevent trivial tampering. The algorithm matches that in
630 // the MakeClassList program used by the J2SE build process.
631 #define JSUM_SEED ((jlong)CONST64(0xcafebabebabecafe))
632 static jlong
633 jsum(jlong start, const char *buf, const int len)
634 {
635 jlong h = start;
636 char *p = (char *)buf, *e = p + len;
637 while (p < e) {
638 char c = *p++;
639 if (c <= ' ') {
640 /* Skip spaces and control characters */
641 continue;
642 }
643 h = 31 * h + c;
644 }
645 return h;
646 }
647
648 // Preload classes from a list, populate the shared spaces and dump to a
649 // file.
650 void MetaspaceShared::preload_and_dump(TRAPS) {
651 TraceTime timer("Dump Shared Spaces", TraceStartupTime);
652 ResourceMark rm;
653
654 // Preload classes to be shared.
655 // Should use some os:: method rather than fopen() here. aB.
656 // Construct the path to the class list (in jre/lib)
657 // Walk up two directories from the location of the VM and
658 // optionally tack on "lib" (depending on platform)
659 char class_list_path[JVM_MAXPATHLEN];
660 os::jvm_path(class_list_path, sizeof(class_list_path));
661 for (int i = 0; i < 3; i++) {
662 char *end = strrchr(class_list_path, *os::file_separator());
663 if (end != NULL) *end = '\0';
664 }
665 int class_list_path_len = (int)strlen(class_list_path);
666 if (class_list_path_len >= 3) {
667 if (strcmp(class_list_path + class_list_path_len - 3, "lib") != 0) {
668 strcat(class_list_path, os::file_separator());
669 strcat(class_list_path, "lib");
670 }
671 }
672 strcat(class_list_path, os::file_separator());
673 strcat(class_list_path, "classlist");
674
675 FILE* file = fopen(class_list_path, "r");
676 if (file != NULL) {
677 jlong computed_jsum = JSUM_SEED;
678 jlong file_jsum = 0;
679
680 char class_name[256];
681 int class_count = 0;
682 GrowableArray<Klass*>* class_promote_order = new GrowableArray<Klass*>();
683
684 // sun.io.Converters
685 static const char obj_array_sig[] = "[[Ljava/lang/Object;";
686 SymbolTable::new_permanent_symbol(obj_array_sig, THREAD);
687
688 // java.util.HashMap
689 static const char map_entry_array_sig[] = "[Ljava/util/Map$Entry;";
690 SymbolTable::new_permanent_symbol(map_entry_array_sig, THREAD);
691
692 tty->print("Loading classes to share ... ");
693 while ((fgets(class_name, sizeof class_name, file)) != NULL) {
694 if (*class_name == '#') {
695 jint fsh, fsl;
696 if (sscanf(class_name, "# %8x%8x\n", &fsh, &fsl) == 2) {
697 file_jsum = ((jlong)(fsh) << 32) | (fsl & 0xffffffff);
698 }
699
700 continue;
701 }
702 // Remove trailing newline
703 size_t name_len = strlen(class_name);
704 class_name[name_len-1] = '\0';
705
706 computed_jsum = jsum(computed_jsum, class_name, (const int)name_len - 1);
707
708 // Got a class name - load it.
709 TempNewSymbol class_name_symbol = SymbolTable::new_permanent_symbol(class_name, THREAD);
710 guarantee(!HAS_PENDING_EXCEPTION, "Exception creating a symbol.");
711 Klass* klass = SystemDictionary::resolve_or_null(class_name_symbol,
712 THREAD);
713 guarantee(!HAS_PENDING_EXCEPTION, "Exception resolving a class.");
714 if (klass != NULL) {
715 if (PrintSharedSpaces && Verbose && WizardMode) {
716 tty->print_cr("Shared spaces preloaded: %s", class_name);
717 }
718
719
720 InstanceKlass* ik = InstanceKlass::cast(klass);
721
722 // Should be class load order as per -XX:+TraceClassLoadingPreorder
723 class_promote_order->append(ik);
724
725 // Link the class to cause the bytecodes to be rewritten and the
726 // cpcache to be created. The linking is done as soon as classes
727 // are loaded in order that the related data structures (klass and
728 // cpCache) are located together.
729
730 if (ik->init_state() < InstanceKlass::linked) {
731 ik->link_class(THREAD);
732 guarantee(!(HAS_PENDING_EXCEPTION), "exception in class rewriting");
733 }
734
735 // TODO: Resolve klasses in constant pool
736 ik->constants()->resolve_class_constants(THREAD);
737
738 class_count++;
739 } else {
740 if (PrintSharedSpaces && Verbose && WizardMode) {
741 tty->cr();
742 tty->print_cr(" Preload failed: %s", class_name);
743 }
744 }
745 file_jsum = 0; // Checksum must be on last line of file
746 }
747 if (computed_jsum != file_jsum) {
748 tty->cr();
749 tty->print_cr("Preload failed: checksum of class list was incorrect.");
750 exit(1);
751 }
752
753 tty->print_cr("done. ");
754
755 if (PrintSharedSpaces) {
756 tty->print_cr("Shared spaces: preloaded %d classes", class_count);
757 }
758
759 // Rewrite and unlink classes.
760 tty->print("Rewriting and linking classes ... ");
761
762 // Link any classes which got missed. (It's not quite clear why
763 // they got missed.) This iteration would be unsafe if we weren't
764 // single-threaded at this point; however we can't do it on the VM
765 // thread because it requires object allocation.
766 SystemDictionary::classes_do(link_shared_classes, CATCH);
767 tty->print_cr("done. ");
768
769 // Create and dump the shared spaces. Everything so far is loaded
770 // with the null class loader.
771 ClassLoaderData* loader_data = ClassLoaderData::the_null_class_loader_data();
772 VM_PopulateDumpSharedSpace op(loader_data, class_promote_order);
773 VMThread::execute(&op);
774
775 } else {
776 char errmsg[JVM_MAXPATHLEN];
777 os::lasterror(errmsg, JVM_MAXPATHLEN);
778 tty->print_cr("Loading classlist failed: %s", errmsg);
779 exit(1);
780 }
781
782 // Since various initialization steps have been undone by this process,
783 // it is not reasonable to continue running a java process.
784 exit(0);
785 }
786
787
788 // Closure for serializing initialization data in from a data area
789 // (ptr_array) read from the shared file.
790
791 class ReadClosure : public SerializeClosure {
792 private:
793 intptr_t** _ptr_array;
794
795 inline intptr_t nextPtr() {
796 return *(*_ptr_array)++;
797 }
798
799 public:
800 ReadClosure(intptr_t** ptr_array) { _ptr_array = ptr_array; }
801
802 void do_ptr(void** p) {
803 assert(*p == NULL, "initializing previous initialized pointer.");
804 intptr_t obj = nextPtr();
805 assert((intptr_t)obj >= 0 || (intptr_t)obj < -100,
806 "hit tag while initializing ptrs.");
807 *p = (void*)obj;
808 }
809
810 void do_tag(int tag) {
811 int old_tag;
812 old_tag = (int)(intptr_t)nextPtr();
813 // do_int(&old_tag);
814 assert(tag == old_tag, "old tag doesn't match");
815 FileMapInfo::assert_mark(tag == old_tag);
816 }
817
818 void do_region(u_char* start, size_t size) {
819 assert((intptr_t)start % sizeof(intptr_t) == 0, "bad alignment");
820 assert(size % sizeof(intptr_t) == 0, "bad size");
821 do_tag((int)size);
822 while (size > 0) {
823 *(intptr_t*)start = nextPtr();
824 start += sizeof(intptr_t);
825 size -= sizeof(intptr_t);
826 }
827 }
828
829 bool reading() const { return true; }
830 };
831
832 // Return true if given address is in the mapped shared space.
833 bool MetaspaceShared::is_in_shared_space(const void* p) {
834 return UseSharedSpaces && FileMapInfo::current_info()->is_in_shared_space(p);
835 }
836
837 void MetaspaceShared::print_shared_spaces() {
838 if (UseSharedSpaces) {
839 FileMapInfo::current_info()->print_shared_spaces();
840 }
841 }
842
843
844 // Map shared spaces at requested addresses and return if succeeded.
845 // Need to keep the bounds of the ro and rw space for the Metaspace::contains
846 // call, or is_in_shared_space.
847 bool MetaspaceShared::map_shared_spaces(FileMapInfo* mapinfo) {
848 size_t image_alignment = mapinfo->alignment();
849
850 #ifndef _WINDOWS
851 // Map in the shared memory and then map the regions on top of it.
852 // On Windows, don't map the memory here because it will cause the
853 // mappings of the regions to fail.
854 ReservedSpace shared_rs = mapinfo->reserve_shared_memory();
855 if (!shared_rs.is_reserved()) return false;
856 #endif
857
858 assert(!DumpSharedSpaces, "Should not be called with DumpSharedSpaces");
859
860 char* _ro_base = NULL;
861 char* _rw_base = NULL;
862 char* _md_base = NULL;
863 char* _mc_base = NULL;
864
865 // Map each shared region
866 if ((_ro_base = mapinfo->map_region(ro)) != NULL &&
867 (_rw_base = mapinfo->map_region(rw)) != NULL &&
868 (_md_base = mapinfo->map_region(md)) != NULL &&
869 (_mc_base = mapinfo->map_region(mc)) != NULL &&
870 (image_alignment == (size_t)max_alignment())) {
871 // Success (no need to do anything)
872 return true;
873 } else {
874 // If there was a failure in mapping any of the spaces, unmap the ones
875 // that succeeded
876 if (_ro_base != NULL) mapinfo->unmap_region(ro);
877 if (_rw_base != NULL) mapinfo->unmap_region(rw);
878 if (_md_base != NULL) mapinfo->unmap_region(md);
879 if (_mc_base != NULL) mapinfo->unmap_region(mc);
880 #ifndef _WINDOWS
881 // Release the entire mapped region
882 shared_rs.release();
883 #endif
884 // If -Xshare:on is specified, print out the error message and exit VM,
885 // otherwise, set UseSharedSpaces to false and continue.
886 if (RequireSharedSpaces) {
887 vm_exit_during_initialization("Unable to use shared archive.", NULL);
888 } else {
889 FLAG_SET_DEFAULT(UseSharedSpaces, false);
890 }
891 return false;
892 }
893 }
894
895 // Read the miscellaneous data from the shared file, and
896 // serialize it out to its various destinations.
897
898 void MetaspaceShared::initialize_shared_spaces() {
899 FileMapInfo *mapinfo = FileMapInfo::current_info();
900
901 char* buffer = mapinfo->region_base(md);
902
903 // Skip over (reserve space for) a list of addresses of C++ vtables
904 // for Klass objects. They get filled in later.
905
906 void** vtbl_list = (void**)buffer;
907 buffer += MetaspaceShared::vtbl_list_size * sizeof(void*);
908 Universe::init_self_patching_vtbl_list(vtbl_list, vtbl_list_size);
909
910 // Skip over (reserve space for) dummy C++ vtables Klass objects.
911 // They are used as is.
912
913 intptr_t vtable_size = *(intptr_t*)buffer;
914 buffer += sizeof(intptr_t);
915 buffer += vtable_size;
916
917 // Create the symbol table using the bucket array at this spot in the
918 // misc data space. Since the symbol table is often modified, this
919 // region (of mapped pages) will be copy-on-write.
920
921 int symbolTableLen = *(intptr_t*)buffer;
922 buffer += sizeof(intptr_t);
923 int number_of_entries = *(intptr_t*)buffer;
924 buffer += sizeof(intptr_t);
925 SymbolTable::create_table((HashtableBucket<mtSymbol>*)buffer, symbolTableLen,
926 number_of_entries);
927 buffer += symbolTableLen;
928
929 // Create the shared dictionary using the bucket array at this spot in
930 // the misc data space. Since the shared dictionary table is never
931 // modified, this region (of mapped pages) will be (effectively, if
932 // not explicitly) read-only.
933
934 int sharedDictionaryLen = *(intptr_t*)buffer;
935 buffer += sizeof(intptr_t);
936 number_of_entries = *(intptr_t*)buffer;
937 buffer += sizeof(intptr_t);
938 SystemDictionary::set_shared_dictionary((HashtableBucket<mtClass>*)buffer,
939 sharedDictionaryLen,
940 number_of_entries);
941 buffer += sharedDictionaryLen;
942
943 // Create the package info table using the bucket array at this spot in
944 // the misc data space. Since the package info table is never
945 // modified, this region (of mapped pages) will be (effectively, if
946 // not explicitly) read-only.
947
948 int pkgInfoLen = *(intptr_t*)buffer;
949 buffer += sizeof(intptr_t);
950 number_of_entries = *(intptr_t*)buffer;
951 buffer += sizeof(intptr_t);
952 ClassLoader::create_package_info_table((HashtableBucket<mtClass>*)buffer, pkgInfoLen,
953 number_of_entries);
954 buffer += pkgInfoLen;
955 ClassLoader::verify();
956
957 // The following data in the shared misc data region are the linked
958 // list elements (HashtableEntry objects) for the symbol table, string
959 // table, and shared dictionary. The heap objects referred to by the
960 // symbol table, string table, and shared dictionary are permanent and
961 // unmovable. Since new entries added to the string and symbol tables
962 // are always added at the beginning of the linked lists, THESE LINKED
963 // LIST ELEMENTS ARE READ-ONLY.
964
965 int len = *(intptr_t*)buffer; // skip over symbol table entries
966 buffer += sizeof(intptr_t);
967 buffer += len;
968
969 len = *(intptr_t*)buffer; // skip over shared dictionary entries
970 buffer += sizeof(intptr_t);
971 buffer += len;
972
973 len = *(intptr_t*)buffer; // skip over package info table entries
974 buffer += sizeof(intptr_t);
975 buffer += len;
976
977 len = *(intptr_t*)buffer; // skip over package info table char[] arrays.
978 buffer += sizeof(intptr_t);
979 buffer += len;
980
981 intptr_t* array = (intptr_t*)buffer;
982 ReadClosure rc(&array);
983 serialize(&rc);
984
985 // Close the mapinfo file
986 mapinfo->close();
987 }
988
989 // JVM/TI RedefineClasses() support:
990 bool MetaspaceShared::remap_shared_readonly_as_readwrite() {
991 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
992
993 if (UseSharedSpaces) {
994 // remap the shared readonly space to shared readwrite, private
995 FileMapInfo* mapinfo = FileMapInfo::current_info();
996 if (!mapinfo->remap_shared_readonly_as_readwrite()) {
997 return false;
998 }
999 }
1000 return true;
1001 }