1 /*
2 * Copyright (c) 2003, 2009, 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 "incls/_precompiled.incl"
26 # include "incls/_dump.cpp.incl"
27
28
29 // Closure to set up the fingerprint field for all methods.
30
31 class FingerprintMethodsClosure: public ObjectClosure {
32 public:
33 void do_object(oop obj) {
34 if (obj->is_method()) {
35 methodOop mobj = (methodOop)obj;
36 ResourceMark rm;
37 (new Fingerprinter(mobj))->fingerprint();
38 }
39 }
40 };
41
42
43
44 // Closure to set the hash value (String.hash field) in all of the
45 // String objects in the heap. Setting the hash value is not required.
46 // However, setting the value in advance prevents the value from being
47 // written later, increasing the likelihood that the shared page contain
48 // the hash can be shared.
49 //
50 // NOTE THAT the algorithm in StringTable::hash_string() MUST MATCH the
51 // algorithm in java.lang.String.hashCode().
52
53 class StringHashCodeClosure: public OopClosure {
54 private:
55 Thread* THREAD;
56 int hash_offset;
57 public:
58 StringHashCodeClosure(Thread* t) {
59 THREAD = t;
60 hash_offset = java_lang_String::hash_offset_in_bytes();
61 }
62
63 void do_oop(oop* p) {
64 if (p != NULL) {
65 oop obj = *p;
66 if (obj->klass() == SystemDictionary::String_klass()) {
67
68 int hash;
69 typeArrayOop value = java_lang_String::value(obj);
70 int length = java_lang_String::length(obj);
71 if (length == 0) {
72 hash = 0;
73 } else {
74 int offset = java_lang_String::offset(obj);
75 jchar* s = value->char_at_addr(offset);
76 hash = StringTable::hash_string(s, length);
77 }
78 obj->int_field_put(hash_offset, hash);
79 }
80 }
81 }
82 void do_oop(narrowOop* p) { ShouldNotReachHere(); }
83 };
84
85
86 // Remove data from objects which should not appear in the shared file
87 // (as it pertains only to the current JVM).
88
89 class RemoveUnshareableInfoClosure : public ObjectClosure {
90 public:
91 void do_object(oop obj) {
92 // Zap data from the objects which is pertains only to this JVM. We
93 // want that data recreated in new JVMs when the shared file is used.
94 if (obj->is_method()) {
95 ((methodOop)obj)->remove_unshareable_info();
96 }
97 else if (obj->is_klass()) {
98 Klass::cast((klassOop)obj)->remove_unshareable_info();
99 }
100
101 // Don't save compiler related special oops (shouldn't be any yet).
102 if (obj->is_methodData() || obj->is_compiledICHolder()) {
103 ShouldNotReachHere();
104 }
105 }
106 };
107
108
109 static bool mark_object(oop obj) {
110 if (obj != NULL &&
111 !obj->is_shared() &&
112 !obj->is_forwarded() &&
113 !obj->is_gc_marked()) {
114 obj->set_mark(markOopDesc::prototype()->set_marked());
115 return true;
116 }
117
118 return false;
119 }
120
121 // Closure: mark objects closure.
122
123 class MarkObjectsOopClosure : public OopClosure {
124 public:
125 void do_oop(oop* p) { mark_object(*p); }
126 void do_oop(narrowOop* p) { ShouldNotReachHere(); }
127 };
128
129
130 class MarkObjectsSkippingKlassesOopClosure : public OopClosure {
131 public:
132 void do_oop(oop* pobj) {
133 oop obj = *pobj;
134 if (obj != NULL &&
135 !obj->is_klass()) {
136 mark_object(obj);
137 }
138 }
139 void do_oop(narrowOop* pobj) { ShouldNotReachHere(); }
140 };
141
142
143 static void mark_object_recursive_skipping_klasses(oop obj) {
144 mark_object(obj);
145 if (obj != NULL) {
146 MarkObjectsSkippingKlassesOopClosure mark_all;
147 obj->oop_iterate(&mark_all);
148 }
149 }
150
151
152 // Closure: mark common read-only objects, excluding symbols
153
154 class MarkCommonReadOnly : public ObjectClosure {
155 private:
156 MarkObjectsOopClosure mark_all;
157 public:
158 void do_object(oop obj) {
159
160 // Mark all constMethod objects.
161
162 if (obj->is_constMethod()) {
163 mark_object(obj);
164 mark_object(constMethodOop(obj)->stackmap_data());
165 // Exception tables are needed by ci code during compilation.
166 mark_object(constMethodOop(obj)->exception_table());
167 }
168
169 // Mark objects referenced by klass objects which are read-only.
170
171 else if (obj->is_klass()) {
172 Klass* k = Klass::cast((klassOop)obj);
173 mark_object(k->secondary_supers());
174
175 // The METHODS() OBJARRAYS CANNOT BE MADE READ-ONLY, even though
176 // it is never modified. Otherwise, they will be pre-marked; the
177 // GC marking phase will skip them; and by skipping them will fail
178 // to mark the methods objects referenced by the array.
179
180 if (obj->blueprint()->oop_is_instanceKlass()) {
181 instanceKlass* ik = instanceKlass::cast((klassOop)obj);
182 mark_object(ik->method_ordering());
183 mark_object(ik->local_interfaces());
184 mark_object(ik->transitive_interfaces());
185 mark_object(ik->fields());
186
187 mark_object(ik->class_annotations());
188
189 mark_object_recursive_skipping_klasses(ik->fields_annotations());
190 mark_object_recursive_skipping_klasses(ik->methods_annotations());
191 mark_object_recursive_skipping_klasses(ik->methods_parameter_annotations());
192 mark_object_recursive_skipping_klasses(ik->methods_default_annotations());
193
194 typeArrayOop inner_classes = ik->inner_classes();
195 if (inner_classes != NULL) {
196 mark_object(inner_classes);
197 }
198 }
199 }
200 }
201 };
202
203
204 // Closure: mark common symbols
205
206 class MarkCommonSymbols : public ObjectClosure {
207 private:
208 MarkObjectsOopClosure mark_all;
209 public:
210 void do_object(oop obj) {
211
212 // Mark symbols refered to by method objects.
213
214 if (obj->is_method()) {
215 methodOop m = methodOop(obj);
216 mark_object(m->name());
217 mark_object(m->signature());
218 }
219
220 // Mark symbols referenced by klass objects which are read-only.
221
222 else if (obj->is_klass()) {
223
224 if (obj->blueprint()->oop_is_instanceKlass()) {
225 instanceKlass* ik = instanceKlass::cast((klassOop)obj);
226 mark_object(ik->name());
227 mark_object(ik->generic_signature());
228 mark_object(ik->source_file_name());
229 mark_object(ik->source_debug_extension());
230
231 typeArrayOop inner_classes = ik->inner_classes();
232 if (inner_classes != NULL) {
233 int length = inner_classes->length();
234 for (int i = 0;
235 i < length;
236 i += instanceKlass::inner_class_next_offset) {
237 int ioff = i + instanceKlass::inner_class_inner_name_offset;
238 int index = inner_classes->ushort_at(ioff);
239 if (index != 0) {
240 mark_object(ik->constants()->symbol_at(index));
241 }
242 }
243 }
244 ik->field_names_and_sigs_iterate(&mark_all);
245 }
246 }
247
248 // Mark symbols referenced by other constantpool entries.
249
250 if (obj->is_constantPool()) {
251 constantPoolOop(obj)->shared_symbols_iterate(&mark_all);
252 }
253 }
254 };
255
256
257 // Closure: mark char arrays used by strings
258
259 class MarkStringValues : public ObjectClosure {
260 private:
261 MarkObjectsOopClosure mark_all;
262 public:
263 void do_object(oop obj) {
264
265 // Character arrays referenced by String objects are read-only.
266
267 if (java_lang_String::is_instance(obj)) {
268 mark_object(java_lang_String::value(obj));
269 }
270 }
271 };
272
273
274 #ifdef DEBUG
275 // Closure: Check for objects left in the heap which have not been moved.
276
277 class CheckRemainingObjects : public ObjectClosure {
278 private:
279 int count;
280
281 public:
282 CheckRemainingObjects() {
283 count = 0;
284 }
285
286 void do_object(oop obj) {
287 if (!obj->is_shared() &&
288 !obj->is_forwarded()) {
289 ++count;
290 if (Verbose) {
291 tty->print("Unreferenced object: ");
292 obj->print_on(tty);
293 }
294 }
295 }
296
297 void status() {
298 tty->print_cr("%d objects no longer referenced, not shared.", count);
299 }
300 };
301 #endif
302
303
304 // Closure: Mark remaining objects read-write, except Strings.
305
306 class MarkReadWriteObjects : public ObjectClosure {
307 private:
308 MarkObjectsOopClosure mark_objects;
309 public:
310 void do_object(oop obj) {
311
312 // The METHODS() OBJARRAYS CANNOT BE MADE READ-ONLY, even though
313 // it is never modified. Otherwise, they will be pre-marked; the
314 // GC marking phase will skip them; and by skipping them will fail
315 // to mark the methods objects referenced by the array.
316
317 if (obj->is_klass()) {
318 mark_object(obj);
319 Klass* k = klassOop(obj)->klass_part();
320 mark_object(k->java_mirror());
321 if (obj->blueprint()->oop_is_instanceKlass()) {
322 instanceKlass* ik = (instanceKlass*)k;
323 mark_object(ik->methods());
324 mark_object(ik->constants());
325 }
326 if (obj->blueprint()->oop_is_javaArray()) {
327 arrayKlass* ak = (arrayKlass*)k;
328 mark_object(ak->component_mirror());
329 }
330 return;
331 }
332
333 // Mark constantPool tags and the constantPoolCache.
334
335 else if (obj->is_constantPool()) {
336 constantPoolOop pool = constantPoolOop(obj);
337 mark_object(pool->cache());
338 pool->shared_tags_iterate(&mark_objects);
339 return;
340 }
341
342 // Mark all method objects.
343
344 if (obj->is_method()) {
345 mark_object(obj);
346 }
347 }
348 };
349
350
351 // Closure: Mark String objects read-write.
352
353 class MarkStringObjects : public ObjectClosure {
354 private:
355 MarkObjectsOopClosure mark_objects;
356 public:
357 void do_object(oop obj) {
358
359 // Mark String objects referenced by constant pool entries.
360
361 if (obj->is_constantPool()) {
362 constantPoolOop pool = constantPoolOop(obj);
363 pool->shared_strings_iterate(&mark_objects);
364 return;
365 }
366 }
367 };
368
369
370 // Move objects matching specified type (ie. lock_bits) to the specified
371 // space.
372
373 class MoveMarkedObjects : public ObjectClosure {
374 private:
375 OffsetTableContigSpace* _space;
376 bool _read_only;
377
378 public:
379 MoveMarkedObjects(OffsetTableContigSpace* space, bool read_only) {
380 _space = space;
381 _read_only = read_only;
382 }
383
384 void do_object(oop obj) {
385 if (obj->is_shared()) {
386 return;
387 }
388 if (obj->is_gc_marked() && obj->forwardee() == NULL) {
389 int s = obj->size();
390 oop sh_obj = (oop)_space->allocate(s);
391 if (sh_obj == NULL) {
392 if (_read_only) {
393 warning("\nThe permanent generation read only space is not large "
394 "enough to \npreload requested classes. Use "
395 "-XX:SharedReadOnlySize= to increase \nthe initial "
396 "size of the read only space.\n");
397 } else {
398 warning("\nThe permanent generation read write space is not large "
399 "enough to \npreload requested classes. Use "
400 "-XX:SharedReadWriteSize= to increase \nthe initial "
401 "size of the read write space.\n");
402 }
403 exit(2);
404 }
405 if (PrintSharedSpaces && Verbose && WizardMode) {
406 tty->print_cr("\nMoveMarkedObjects: " PTR_FORMAT " -> " PTR_FORMAT " %s", obj, sh_obj,
407 (_read_only ? "ro" : "rw"));
408 }
409 Copy::aligned_disjoint_words((HeapWord*)obj, (HeapWord*)sh_obj, s);
410 obj->forward_to(sh_obj);
411 if (_read_only) {
412 // Readonly objects: set hash value to self pointer and make gc_marked.
413 sh_obj->forward_to(sh_obj);
414 } else {
415 sh_obj->init_mark();
416 }
417 }
418 }
419 };
420
421 static void mark_and_move(oop obj, MoveMarkedObjects* move) {
422 if (mark_object(obj)) move->do_object(obj);
423 }
424
425 enum order_policy {
426 OP_favor_startup = 0,
427 OP_balanced = 1,
428 OP_favor_runtime = 2
429 };
430
431 static void mark_and_move_for_policy(order_policy policy, oop obj, MoveMarkedObjects* move) {
432 if (SharedOptimizeColdStartPolicy >= policy) mark_and_move(obj, move);
433 }
434
435 class MarkAndMoveOrderedReadOnly : public ObjectClosure {
436 private:
437 MoveMarkedObjects *_move_ro;
438
439 public:
440 MarkAndMoveOrderedReadOnly(MoveMarkedObjects *move_ro) : _move_ro(move_ro) {}
441
442 void do_object(oop obj) {
443 if (obj->is_klass() && obj->blueprint()->oop_is_instanceKlass()) {
444 instanceKlass* ik = instanceKlass::cast((klassOop)obj);
445 int i;
446
447 mark_and_move_for_policy(OP_favor_startup, ik->name(), _move_ro);
448
449 if (ik->super() != NULL) {
450 do_object(ik->super());
451 }
452
453 objArrayOop interfaces = ik->local_interfaces();
454 mark_and_move_for_policy(OP_favor_startup, interfaces, _move_ro);
455 for(i = 0; i < interfaces->length(); i++) {
456 klassOop k = klassOop(interfaces->obj_at(i));
457 mark_and_move_for_policy(OP_favor_startup, k->klass_part()->name(), _move_ro);
458 do_object(k);
459 }
460
461 objArrayOop methods = ik->methods();
462 for(i = 0; i < methods->length(); i++) {
463 methodOop m = methodOop(methods->obj_at(i));
464 mark_and_move_for_policy(OP_favor_startup, m->constMethod(), _move_ro);
465 mark_and_move_for_policy(OP_favor_runtime, m->constMethod()->exception_table(), _move_ro);
466 mark_and_move_for_policy(OP_favor_runtime, m->constMethod()->stackmap_data(), _move_ro);
467
468 // We don't move the name symbolOop here because it may invalidate
469 // method ordering, which is dependent on the address of the name
470 // symbolOop. It will get promoted later with the other symbols.
471 // Method name is rarely accessed during classloading anyway.
472 // mark_and_move_for_policy(OP_balanced, m->name(), _move_ro);
473
474 mark_and_move_for_policy(OP_favor_startup, m->signature(), _move_ro);
475 }
476
477 mark_and_move_for_policy(OP_favor_startup, ik->transitive_interfaces(), _move_ro);
478 mark_and_move_for_policy(OP_favor_startup, ik->fields(), _move_ro);
479
480 mark_and_move_for_policy(OP_favor_runtime, ik->secondary_supers(), _move_ro);
481 mark_and_move_for_policy(OP_favor_runtime, ik->method_ordering(), _move_ro);
482 mark_and_move_for_policy(OP_favor_runtime, ik->class_annotations(), _move_ro);
483 mark_and_move_for_policy(OP_favor_runtime, ik->fields_annotations(), _move_ro);
484 mark_and_move_for_policy(OP_favor_runtime, ik->methods_annotations(), _move_ro);
485 mark_and_move_for_policy(OP_favor_runtime, ik->methods_parameter_annotations(), _move_ro);
486 mark_and_move_for_policy(OP_favor_runtime, ik->methods_default_annotations(), _move_ro);
487 mark_and_move_for_policy(OP_favor_runtime, ik->inner_classes(), _move_ro);
488 mark_and_move_for_policy(OP_favor_runtime, ik->secondary_supers(), _move_ro);
489 }
490 }
491 };
492
493 class MarkAndMoveOrderedReadWrite: public ObjectClosure {
494 private:
495 MoveMarkedObjects *_move_rw;
496
497 public:
498 MarkAndMoveOrderedReadWrite(MoveMarkedObjects *move_rw) : _move_rw(move_rw) {}
499
500 void do_object(oop obj) {
501 if (obj->is_klass() && obj->blueprint()->oop_is_instanceKlass()) {
502 instanceKlass* ik = instanceKlass::cast((klassOop)obj);
503 int i;
504
505 mark_and_move_for_policy(OP_favor_startup, ik->as_klassOop(), _move_rw);
506
507 if (ik->super() != NULL) {
508 do_object(ik->super());
509 }
510
511 objArrayOop interfaces = ik->local_interfaces();
512 for(i = 0; i < interfaces->length(); i++) {
513 klassOop k = klassOop(interfaces->obj_at(i));
514 mark_and_move_for_policy(OP_favor_startup, k, _move_rw);
515 do_object(k);
516 }
517
518 objArrayOop methods = ik->methods();
519 mark_and_move_for_policy(OP_favor_startup, methods, _move_rw);
520 for(i = 0; i < methods->length(); i++) {
521 methodOop m = methodOop(methods->obj_at(i));
522 mark_and_move_for_policy(OP_favor_startup, m, _move_rw);
523 mark_and_move_for_policy(OP_favor_startup, ik->constants(), _move_rw); // idempotent
524 mark_and_move_for_policy(OP_balanced, ik->constants()->cache(), _move_rw); // idempotent
525 mark_and_move_for_policy(OP_balanced, ik->constants()->tags(), _move_rw); // idempotent
526 }
527
528 mark_and_move_for_policy(OP_favor_startup, ik->as_klassOop()->klass(), _move_rw);
529 mark_and_move_for_policy(OP_favor_startup, ik->constants()->klass(), _move_rw);
530
531 // Although Java mirrors are marked in MarkReadWriteObjects,
532 // apparently they were never moved into shared spaces since
533 // MoveMarkedObjects skips marked instance oops. This may
534 // be a bug in the original implementation or simply the vestige
535 // of an abandoned experiment. Nevertheless we leave a hint
536 // here in case this capability is ever correctly implemented.
537 //
538 // mark_and_move_for_policy(OP_favor_runtime, ik->java_mirror(), _move_rw);
539 }
540 }
541
542 };
543
544 // Adjust references in oops to refer to shared spaces.
545
546 class ResolveForwardingClosure: public OopClosure {
547 public:
548 void do_oop(oop* p) {
549 oop obj = *p;
550 if (!obj->is_shared()) {
551 if (obj != NULL) {
552 oop f = obj->forwardee();
553 guarantee(f->is_shared(), "Oop doesn't refer to shared space.");
554 *p = f;
555 }
556 }
557 }
558 void do_oop(narrowOop* pobj) { ShouldNotReachHere(); }
559 };
560
561
562 void sort_methods(instanceKlass* ik, TRAPS) {
563 klassOop super = ik->super();
564 if (super != NULL) {
565 sort_methods(instanceKlass::cast(super), THREAD);
566 }
567
568 // The methods array must be ordered by symbolOop address. (See
569 // classFileParser.cpp where methods in a class are originally
570 // sorted.) Since objects have just be reordered, this must be
571 // corrected.
572 methodOopDesc::sort_methods(ik->methods(),
573 ik->methods_annotations(),
574 ik->methods_parameter_annotations(),
575 ik->methods_default_annotations(),
576 true /* idempotent, slow */);
577
578 // Itable indices are calculated based on methods array order
579 // (see klassItable::compute_itable_index()). Must reinitialize.
580 // We assume that since checkconstraints is false, this method
581 // cannot throw an exception. An exception here would be
582 // problematic since this is the VMThread, not a JavaThread.
583 ik->itable()->initialize_itable(false, THREAD);
584 }
585
586 // Sort methods if the oop is an instanceKlass.
587
588 class SortMethodsClosure: public ObjectClosure {
589 private:
590 Thread* _thread;
591
592 public:
593 SortMethodsClosure(Thread* thread) : _thread(thread) {}
594
595 void do_object(oop obj) {
596 // instanceKlass objects need some adjustment.
597 if (obj->blueprint()->oop_is_instanceKlass()) {
598 instanceKlass* ik = instanceKlass::cast((klassOop)obj);
599
600 sort_methods(ik, _thread);
601 }
602 }
603 };
604
605
606 // Adjust references in oops to refer to shared spaces.
607
608 class PatchOopsClosure: public ObjectClosure {
609 private:
610 Thread* _thread;
611 ResolveForwardingClosure resolve;
612
613 public:
614 PatchOopsClosure(Thread* thread) : _thread(thread) {}
615
616 void do_object(oop obj) {
617 obj->oop_iterate_header(&resolve);
618 obj->oop_iterate(&resolve);
619
620 assert(obj->klass()->is_shared(), "Klass not pointing into shared space.");
621
622 // If the object is a Java object or class which might (in the
623 // future) contain a reference to a young gen object, add it to the
624 // list.
625
626 if (obj->is_klass() || obj->is_instance()) {
627 if (obj->is_klass() ||
628 obj->is_a(SystemDictionary::Class_klass()) ||
629 obj->is_a(SystemDictionary::Throwable_klass())) {
630 // Do nothing
631 }
632 else if (obj->is_a(SystemDictionary::String_klass())) {
633 // immutable objects.
634 } else {
635 // someone added an object we hadn't accounted for.
636 ShouldNotReachHere();
637 }
638 }
639 }
640 };
641
642
643 // Empty the young and old generations.
644
645 class ClearSpaceClosure : public SpaceClosure {
646 public:
647 void do_space(Space* s) {
648 s->clear(SpaceDecorator::Mangle);
649 }
650 };
651
652
653 // Closure for serializing initialization data out to a data area to be
654 // written to the shared file.
655
656 class WriteClosure : public SerializeOopClosure {
657 private:
658 oop* top;
659 char* end;
660
661 void out_of_space() {
662 warning("\nThe shared miscellaneous data space is not large "
663 "enough to \npreload requested classes. Use "
664 "-XX:SharedMiscDataSize= to increase \nthe initial "
665 "size of the miscellaneous data space.\n");
666 exit(2);
667 }
668
669
670 inline void check_space() {
671 if ((char*)top + sizeof(oop) > end) {
672 out_of_space();
673 }
674 }
675
676
677 public:
678 WriteClosure(char* md_top, char* md_end) {
679 top = (oop*)md_top;
680 end = md_end;
681 }
682
683 char* get_top() { return (char*)top; }
684
685 void do_oop(oop* p) {
686 check_space();
687 oop obj = *p;
688 assert(obj->is_oop_or_null(), "invalid oop");
689 assert(obj == NULL || obj->is_shared(),
690 "Oop in shared space not pointing into shared space.");
691 *top = obj;
692 ++top;
693 }
694
695 void do_oop(narrowOop* pobj) { ShouldNotReachHere(); }
696
697 void do_int(int* p) {
698 check_space();
699 *top = (oop)(intptr_t)*p;
700 ++top;
701 }
702
703 void do_size_t(size_t* p) {
704 check_space();
705 *top = (oop)(intptr_t)*p;
706 ++top;
707 }
708
709 void do_ptr(void** p) {
710 check_space();
711 *top = (oop)*p;
712 ++top;
713 }
714
715 void do_ptr(HeapWord** p) { do_ptr((void **) p); }
716
717 void do_tag(int tag) {
718 check_space();
719 *top = (oop)(intptr_t)tag;
720 ++top;
721 }
722
723 void do_region(u_char* start, size_t size) {
724 if ((char*)top + size > end) {
725 out_of_space();
726 }
727 assert((intptr_t)start % sizeof(oop) == 0, "bad alignment");
728 assert(size % sizeof(oop) == 0, "bad size");
729 do_tag((int)size);
730 while (size > 0) {
731 *top = *(oop*)start;
732 ++top;
733 start += sizeof(oop);
734 size -= sizeof(oop);
735 }
736 }
737
738 bool reading() const { return false; }
739 };
740
741
742 class ResolveConstantPoolsClosure : public ObjectClosure {
743 private:
744 TRAPS;
745 public:
746 ResolveConstantPoolsClosure(Thread *t) {
747 __the_thread__ = t;
748 }
749 void do_object(oop obj) {
750 if (obj->is_constantPool()) {
751 constantPoolOop cpool = (constantPoolOop)obj;
752 int unresolved = cpool->pre_resolve_shared_klasses(THREAD);
753 }
754 }
755 };
756
757
758 // Print a summary of the contents of the read/write spaces to help
759 // identify objects which might be able to be made read-only. At this
760 // point, the objects have been written, and we can trash them as
761 // needed.
762
763 static void print_contents() {
764 if (PrintSharedSpaces) {
765 GenCollectedHeap* gch = GenCollectedHeap::heap();
766 CompactingPermGenGen* gen = (CompactingPermGenGen*)gch->perm_gen();
767
768 // High level summary of the read-only space:
769
770 ClassifyObjectClosure coc;
771 tty->cr(); tty->print_cr("ReadOnly space:");
772 gen->ro_space()->object_iterate(&coc);
773 coc.print();
774
775 // High level summary of the read-write space:
776
777 coc.reset();
778 tty->cr(); tty->print_cr("ReadWrite space:");
779 gen->rw_space()->object_iterate(&coc);
780 coc.print();
781
782 // Reset counters
783
784 ClearAllocCountClosure cacc;
785 gen->ro_space()->object_iterate(&cacc);
786 gen->rw_space()->object_iterate(&cacc);
787 coc.reset();
788
789 // Lower level summary of the read-only space:
790
791 gen->ro_space()->object_iterate(&coc);
792 tty->cr(); tty->print_cr("ReadOnly space:");
793 ClassifyInstanceKlassClosure cikc;
794 gen->rw_space()->object_iterate(&cikc);
795 cikc.print();
796
797 // Reset counters
798
799 gen->ro_space()->object_iterate(&cacc);
800 gen->rw_space()->object_iterate(&cacc);
801 coc.reset();
802
803 // Lower level summary of the read-write space:
804
805 gen->rw_space()->object_iterate(&coc);
806 cikc.reset();
807 tty->cr(); tty->print_cr("ReadWrite space:");
808 gen->rw_space()->object_iterate(&cikc);
809 cikc.print();
810 }
811 }
812
813
814 // Patch C++ vtable pointer in klass oops.
815
816 // Klass objects contain references to c++ vtables in the JVM library.
817 // Fix them to point to our constructed vtables. However, don't iterate
818 // across the space while doing this, as that causes the vtables to be
819 // patched, undoing our useful work. Instead, iterate to make a list,
820 // then use the list to do the fixing.
821 //
822 // Our constructed vtables:
823 // Dump time:
824 // 1. init_self_patching_vtbl_list: table of pointers to current virtual method addrs
825 // 2. generate_vtable_methods: create jump table, appended to above vtbl_list
826 // 3. PatchKlassVtables: for Klass list, patch the vtable entry to point to jump table
827 // rather than to current vtbl
828 // Table layout: NOTE FIXED SIZE
829 // 1. vtbl pointers
830 // 2. #Klass X #virtual methods per Klass
831 // 1 entry for each, in the order:
832 // Klass1:method1 entry, Klass1:method2 entry, ... Klass1:method<num_virtuals> entry
833 // Klass2:method1 entry, Klass2:method2 entry, ... Klass2:method<num_virtuals> entry
834 // ...
835 // Klass<vtbl_list_size>:method1 entry, Klass<vtbl_list_size>:method2 entry,
836 // ... Klass<vtbl_list_size>:method<num_virtuals> entry
837 // Sample entry: (Sparc):
838 // save(sp, -256, sp)
839 // ba,pt common_code
840 // mov XXX, %L0 %L0 gets: Klass index <<8 + method index (note: max method index 255)
841 //
842 // Restore time:
843 // 1. initialize_oops: reserve space for table
844 // 2. init_self_patching_vtbl_list: update pointers to NEW virtual method addrs in text
845 //
846 // Execution time:
847 // First virtual method call for any object of these Klass types:
848 // 1. object->klass->klass_part
849 // 2. vtable entry for that klass_part points to the jump table entries
850 // 3. branches to common_code with %O0/klass_part, %L0: Klass index <<8 + method index
851 // 4. common_code:
852 // Get address of new vtbl pointer for this Klass from updated table
853 // Update new vtbl pointer in the Klass: future virtual calls go direct
854 // Jump to method, using new vtbl pointer and method index
855
856 class PatchKlassVtables: public ObjectClosure {
857 private:
858 void* _vtbl_ptr;
859 VirtualSpace* _md_vs;
860 GrowableArray<klassOop>* _klass_objects;
861
862 public:
863
864 PatchKlassVtables(void* vtbl_ptr, VirtualSpace* md_vs) {
865 _vtbl_ptr = vtbl_ptr;
866 _md_vs = md_vs;
867 _klass_objects = new GrowableArray<klassOop>();
868 }
869
870
871 void do_object(oop obj) {
872 if (obj->is_klass()) {
873 _klass_objects->append(klassOop(obj));
874 }
875 }
876
877
878 void patch(void** vtbl_list, int vtbl_list_size) {
879 for (int i = 0; i < _klass_objects->length(); ++i) {
880 klassOop obj = (klassOop)_klass_objects->at(i);
881 Klass* k = obj->klass_part();
882 void* v = *(void**)k;
883
884 int n;
885 for (n = 0; n < vtbl_list_size; ++n) {
886 *(void**)k = NULL;
887 if (vtbl_list[n] == v) {
888 *(void**)k = (void**)_vtbl_ptr +
889 (n * CompactingPermGenGen::num_virtuals);
890 break;
891 }
892 }
893 guarantee(n < vtbl_list_size, "unable to find matching vtbl pointer");
894 }
895 }
896 };
897
898
899 // Populate the shared space.
900
901 class VM_PopulateDumpSharedSpace: public VM_Operation {
902 private:
903 GrowableArray<oop> *_class_promote_order;
904 OffsetTableContigSpace* _ro_space;
905 OffsetTableContigSpace* _rw_space;
906 VirtualSpace* _md_vs;
907 VirtualSpace* _mc_vs;
908
909 public:
910 VM_PopulateDumpSharedSpace(GrowableArray<oop> *class_promote_order,
911 OffsetTableContigSpace* ro_space,
912 OffsetTableContigSpace* rw_space,
913 VirtualSpace* md_vs, VirtualSpace* mc_vs) {
914 _class_promote_order = class_promote_order;
915 _ro_space = ro_space;
916 _rw_space = rw_space;
917 _md_vs = md_vs;
918 _mc_vs = mc_vs;
919 }
920
921 VMOp_Type type() const { return VMOp_PopulateDumpSharedSpace; }
922 void doit() {
923 Thread* THREAD = VMThread::vm_thread();
924 NOT_PRODUCT(SystemDictionary::verify();)
925 // The following guarantee is meant to ensure that no loader constraints
926 // exist yet, since the constraints table is not shared. This becomes
927 // more important now that we don't re-initialize vtables/itables for
928 // shared classes at runtime, where constraints were previously created.
929 guarantee(SystemDictionary::constraints()->number_of_entries() == 0,
930 "loader constraints are not saved");
931 // Revisit and implement this if we prelink method handle call sites:
932 guarantee(SystemDictionary::invoke_method_table() == NULL ||
933 SystemDictionary::invoke_method_table()->number_of_entries() == 0,
934 "invoke method table is not saved");
935 GenCollectedHeap* gch = GenCollectedHeap::heap();
936
937 // At this point, many classes have been loaded.
938
939 // Update all the fingerprints in the shared methods.
940
941 tty->print("Calculating fingerprints ... ");
942 FingerprintMethodsClosure fpmc;
943 gch->object_iterate(&fpmc);
944 tty->print_cr("done. ");
945
946 // Remove all references outside the heap.
947
948 tty->print("Removing unshareable information ... ");
949 RemoveUnshareableInfoClosure ruic;
950 gch->object_iterate(&ruic);
951 tty->print_cr("done. ");
952
953 // Move the objects in three passes.
954
955 MarkObjectsOopClosure mark_all;
956 MarkCommonReadOnly mark_common_ro;
957 MarkCommonSymbols mark_common_symbols;
958 MarkStringValues mark_string_values;
959 MarkReadWriteObjects mark_rw;
960 MarkStringObjects mark_strings;
961 MoveMarkedObjects move_ro(_ro_space, true);
962 MoveMarkedObjects move_rw(_rw_space, false);
963
964 // The SharedOptimizeColdStart VM option governs the new layout
965 // algorithm for promoting classes into the shared archive.
966 // The general idea is to minimize cold start time by laying
967 // out the objects in the order they are accessed at startup time.
968 // By doing this we are trying to eliminate out-of-order accesses
969 // in the shared archive. This benefits cold startup time by making
970 // disk reads as sequential as possible during class loading and
971 // bootstrapping activities. There may also be a small secondary
972 // effect of better "packing" of more commonly used data on a smaller
973 // number of pages, although no direct benefit has been measured from
974 // this effect.
975 //
976 // At the class level of granularity, the promotion order is dictated
977 // by the classlist file whose generation is discussed elsewhere.
978 //
979 // At smaller granularity, optimal ordering was determined by an
980 // offline analysis of object access order in the shared archive.
981 // The dbx watchpoint facility, combined with SA post-processing,
982 // was used to observe common access patterns primarily during
983 // classloading. This information was used to craft the promotion
984 // order seen in the following closures.
985 //
986 // The observed access order is mostly governed by what happens
987 // in SystemDictionary::load_shared_class(). NOTE WELL - care
988 // should be taken when making changes to this method, because it
989 // may invalidate assumptions made about access order!
990 //
991 // (Ideally, there would be a better way to manage changes to
992 // the access order. Unfortunately a generic in-VM solution for
993 // dynamically observing access order and optimizing shared
994 // archive layout is pretty difficult. We go with the static
995 // analysis because the code is fairly mature at this point
996 // and we're betting that the access order won't change much.)
997
998 MarkAndMoveOrderedReadOnly mark_and_move_ordered_ro(&move_ro);
999 MarkAndMoveOrderedReadWrite mark_and_move_ordered_rw(&move_rw);
1000
1001 // Phase 1a: move commonly used read-only objects to the read-only space.
1002
1003 if (SharedOptimizeColdStart) {
1004 tty->print("Moving pre-ordered read-only objects to shared space at " PTR_FORMAT " ... ",
1005 _ro_space->top());
1006 for (int i = 0; i < _class_promote_order->length(); i++) {
1007 oop obj = _class_promote_order->at(i);
1008 mark_and_move_ordered_ro.do_object(obj);
1009 }
1010 tty->print_cr("done. ");
1011 }
1012
1013 tty->print("Moving read-only objects to shared space at " PTR_FORMAT " ... ",
1014 _ro_space->top());
1015 gch->object_iterate(&mark_common_ro);
1016 gch->object_iterate(&move_ro);
1017 tty->print_cr("done. ");
1018
1019 // Phase 1b: move commonly used symbols to the read-only space.
1020
1021 tty->print("Moving common symbols to shared space at " PTR_FORMAT " ... ",
1022 _ro_space->top());
1023 gch->object_iterate(&mark_common_symbols);
1024 gch->object_iterate(&move_ro);
1025 tty->print_cr("done. ");
1026
1027 // Phase 1c: move remaining symbols to the read-only space
1028 // (e.g. String initializers).
1029
1030 tty->print("Moving remaining symbols to shared space at " PTR_FORMAT " ... ",
1031 _ro_space->top());
1032 vmSymbols::oops_do(&mark_all, true);
1033 gch->object_iterate(&move_ro);
1034 tty->print_cr("done. ");
1035
1036 // Phase 1d: move String character arrays to the read-only space.
1037
1038 tty->print("Moving string char arrays to shared space at " PTR_FORMAT " ... ",
1039 _ro_space->top());
1040 gch->object_iterate(&mark_string_values);
1041 gch->object_iterate(&move_ro);
1042 tty->print_cr("done. ");
1043
1044 // Phase 2: move all remaining symbols to the read-only space. The
1045 // remaining symbols are assumed to be string initializers no longer
1046 // referenced.
1047
1048 void* extra_symbols = _ro_space->top();
1049 tty->print("Moving additional symbols to shared space at " PTR_FORMAT " ... ",
1050 _ro_space->top());
1051 SymbolTable::oops_do(&mark_all);
1052 gch->object_iterate(&move_ro);
1053 tty->print_cr("done. ");
1054 tty->print_cr("Read-only space ends at " PTR_FORMAT ", %d bytes.",
1055 _ro_space->top(), _ro_space->used());
1056
1057 // Phase 3: move read-write objects to the read-write space, except
1058 // Strings.
1059
1060 if (SharedOptimizeColdStart) {
1061 tty->print("Moving pre-ordered read-write objects to shared space at " PTR_FORMAT " ... ",
1062 _rw_space->top());
1063 for (int i = 0; i < _class_promote_order->length(); i++) {
1064 oop obj = _class_promote_order->at(i);
1065 mark_and_move_ordered_rw.do_object(obj);
1066 }
1067 tty->print_cr("done. ");
1068 }
1069 tty->print("Moving read-write objects to shared space at " PTR_FORMAT " ... ",
1070 _rw_space->top());
1071 Universe::oops_do(&mark_all, true);
1072 SystemDictionary::oops_do(&mark_all);
1073 oop tmp = Universe::arithmetic_exception_instance();
1074 mark_object(java_lang_Throwable::message(tmp));
1075 gch->object_iterate(&mark_rw);
1076 gch->object_iterate(&move_rw);
1077 tty->print_cr("done. ");
1078
1079 // Phase 4: move String objects to the read-write space.
1080
1081 tty->print("Moving String objects to shared space at " PTR_FORMAT " ... ",
1082 _rw_space->top());
1083 StringTable::oops_do(&mark_all);
1084 gch->object_iterate(&mark_strings);
1085 gch->object_iterate(&move_rw);
1086 tty->print_cr("done. ");
1087 tty->print_cr("Read-write space ends at " PTR_FORMAT ", %d bytes.",
1088 _rw_space->top(), _rw_space->used());
1089
1090 #ifdef DEBUG
1091 // Check: scan for objects which were not moved.
1092
1093 CheckRemainingObjects check_objects;
1094 gch->object_iterate(&check_objects);
1095 check_objects.status();
1096 #endif
1097
1098 // Resolve forwarding in objects and saved C++ structures
1099 tty->print("Updating references to shared objects ... ");
1100 ResolveForwardingClosure resolve;
1101 Universe::oops_do(&resolve);
1102 SystemDictionary::oops_do(&resolve);
1103 StringTable::oops_do(&resolve);
1104 SymbolTable::oops_do(&resolve);
1105 vmSymbols::oops_do(&resolve);
1106
1107 // Set up the share data and shared code segments.
1108
1109 char* md_top = _md_vs->low();
1110 char* md_end = _md_vs->high();
1111 char* mc_top = _mc_vs->low();
1112 char* mc_end = _mc_vs->high();
1113
1114 // Reserve space for the list of klassOops whose vtables are used
1115 // for patching others as needed.
1116
1117 void** vtbl_list = (void**)md_top;
1118 int vtbl_list_size = CompactingPermGenGen::vtbl_list_size;
1119 Universe::init_self_patching_vtbl_list(vtbl_list, vtbl_list_size);
1120
1121 md_top += vtbl_list_size * sizeof(void*);
1122 void* vtable = md_top;
1123
1124 // Reserve space for a new dummy vtable for klass objects in the
1125 // heap. Generate self-patching vtable entries.
1126
1127 CompactingPermGenGen::generate_vtable_methods(vtbl_list,
1128 &vtable,
1129 &md_top, md_end,
1130 &mc_top, mc_end);
1131
1132 // Fix (forward) all of the references in these shared objects (which
1133 // are required to point ONLY to objects in the shared spaces).
1134 // Also, create a list of all objects which might later contain a
1135 // reference to a younger generation object.
1136
1137 CompactingPermGenGen* gen = (CompactingPermGenGen*)gch->perm_gen();
1138 PatchOopsClosure patch(THREAD);
1139 gen->ro_space()->object_iterate(&patch);
1140 gen->rw_space()->object_iterate(&patch);
1141
1142 // Previously method sorting was done concurrently with forwarding
1143 // pointer resolution in the shared spaces. This imposed an ordering
1144 // restriction in that methods were required to be promoted/patched
1145 // before their holder classes. (Because constant pool pointers in
1146 // methodKlasses are required to be resolved before their holder class
1147 // is visited for sorting, otherwise methods are sorted by incorrect,
1148 // pre-forwarding addresses.)
1149 //
1150 // Now, we reorder methods as a separate step after ALL forwarding
1151 // pointer resolution, so that methods can be promoted in any order
1152 // with respect to their holder classes.
1153
1154 SortMethodsClosure sort(THREAD);
1155 gen->ro_space()->object_iterate(&sort);
1156 gen->rw_space()->object_iterate(&sort);
1157 tty->print_cr("done. ");
1158 tty->cr();
1159
1160 // Reorder the system dictionary. (Moving the symbols opps affects
1161 // how the hash table indices are calculated.)
1162
1163 SystemDictionary::reorder_dictionary();
1164
1165 // Empty the non-shared heap (because most of the objects were
1166 // copied out, and the remainder cannot be considered valid oops).
1167
1168 ClearSpaceClosure csc;
1169 for (int i = 0; i < gch->n_gens(); ++i) {
1170 gch->get_gen(i)->space_iterate(&csc);
1171 }
1172 csc.do_space(gen->the_space());
1173 NOT_PRODUCT(SystemDictionary::verify();)
1174
1175 // Copy the String table, the symbol table, and the system
1176 // dictionary to the shared space in usable form. Copy the hastable
1177 // buckets first [read-write], then copy the linked lists of entries
1178 // [read-only].
1179
1180 SymbolTable::reverse(extra_symbols);
1181 NOT_PRODUCT(SymbolTable::verify());
1182 SymbolTable::copy_buckets(&md_top, md_end);
1183
1184 StringTable::reverse();
1185 NOT_PRODUCT(StringTable::verify());
1186 StringTable::copy_buckets(&md_top, md_end);
1187
1188 SystemDictionary::reverse();
1189 SystemDictionary::copy_buckets(&md_top, md_end);
1190
1191 ClassLoader::verify();
1192 ClassLoader::copy_package_info_buckets(&md_top, md_end);
1193 ClassLoader::verify();
1194
1195 SymbolTable::copy_table(&md_top, md_end);
1196 StringTable::copy_table(&md_top, md_end);
1197 SystemDictionary::copy_table(&md_top, md_end);
1198 ClassLoader::verify();
1199 ClassLoader::copy_package_info_table(&md_top, md_end);
1200 ClassLoader::verify();
1201
1202 // Print debug data.
1203
1204 if (PrintSharedSpaces) {
1205 const char* fmt = "%s space: " PTR_FORMAT " out of " PTR_FORMAT " bytes allocated at " PTR_FORMAT ".";
1206 tty->print_cr(fmt, "ro", _ro_space->used(), _ro_space->capacity(),
1207 _ro_space->bottom());
1208 tty->print_cr(fmt, "rw", _rw_space->used(), _rw_space->capacity(),
1209 _rw_space->bottom());
1210 }
1211
1212 // Write the oop data to the output array.
1213
1214 WriteClosure wc(md_top, md_end);
1215 CompactingPermGenGen::serialize_oops(&wc);
1216 md_top = wc.get_top();
1217
1218 // Update the vtable pointers in all of the Klass objects in the
1219 // heap. They should point to newly generated vtable.
1220
1221 PatchKlassVtables pkvt(vtable, _md_vs);
1222 _rw_space->object_iterate(&pkvt);
1223 pkvt.patch(vtbl_list, vtbl_list_size);
1224
1225 char* saved_vtbl = (char*)malloc(vtbl_list_size * sizeof(void*));
1226 memmove(saved_vtbl, vtbl_list, vtbl_list_size * sizeof(void*));
1227 memset(vtbl_list, 0, vtbl_list_size * sizeof(void*));
1228
1229 // Create and write the archive file that maps the shared spaces.
1230
1231 FileMapInfo* mapinfo = new FileMapInfo();
1232 mapinfo->populate_header(gch->gen_policy()->max_alignment());
1233
1234 // Pass 1 - update file offsets in header.
1235 mapinfo->write_header();
1236 mapinfo->write_space(CompactingPermGenGen::ro, _ro_space, true);
1237 _ro_space->set_saved_mark();
1238 mapinfo->write_space(CompactingPermGenGen::rw, _rw_space, false);
1239 _rw_space->set_saved_mark();
1240 mapinfo->write_region(CompactingPermGenGen::md, _md_vs->low(),
1241 pointer_delta(md_top, _md_vs->low(), sizeof(char)),
1242 SharedMiscDataSize,
1243 false, false);
1244 mapinfo->write_region(CompactingPermGenGen::mc, _mc_vs->low(),
1245 pointer_delta(mc_top, _mc_vs->low(), sizeof(char)),
1246 SharedMiscCodeSize,
1247 true, true);
1248
1249 // Pass 2 - write data.
1250 mapinfo->open_for_write();
1251 mapinfo->write_header();
1252 mapinfo->write_space(CompactingPermGenGen::ro, _ro_space, true);
1253 mapinfo->write_space(CompactingPermGenGen::rw, _rw_space, false);
1254 mapinfo->write_region(CompactingPermGenGen::md, _md_vs->low(),
1255 pointer_delta(md_top, _md_vs->low(), sizeof(char)),
1256 SharedMiscDataSize,
1257 false, false);
1258 mapinfo->write_region(CompactingPermGenGen::mc, _mc_vs->low(),
1259 pointer_delta(mc_top, _mc_vs->low(), sizeof(char)),
1260 SharedMiscCodeSize,
1261 true, true);
1262 mapinfo->close();
1263
1264 // Summarize heap.
1265 memmove(vtbl_list, saved_vtbl, vtbl_list_size * sizeof(void*));
1266 print_contents();
1267 }
1268 }; // class VM_PopulateDumpSharedSpace
1269
1270
1271 // Populate the shared spaces and dump to a file.
1272
1273 jint CompactingPermGenGen::dump_shared(GrowableArray<oop>* class_promote_order, TRAPS) {
1274 GenCollectedHeap* gch = GenCollectedHeap::heap();
1275
1276 // Calculate hash values for all of the (interned) strings to avoid
1277 // writes to shared pages in the future.
1278
1279 tty->print("Calculating hash values for String objects .. ");
1280 StringHashCodeClosure shcc(THREAD);
1281 StringTable::oops_do(&shcc);
1282 tty->print_cr("done. ");
1283
1284 CompactingPermGenGen* gen = (CompactingPermGenGen*)gch->perm_gen();
1285 VM_PopulateDumpSharedSpace op(class_promote_order,
1286 gen->ro_space(), gen->rw_space(),
1287 gen->md_space(), gen->mc_space());
1288 VMThread::execute(&op);
1289 return JNI_OK;
1290 }
1291
1292
1293 class LinkClassesClosure : public ObjectClosure {
1294 private:
1295 Thread* THREAD;
1296
1297 public:
1298 LinkClassesClosure(Thread* thread) : THREAD(thread) {}
1299
1300 void do_object(oop obj) {
1301 if (obj->is_klass()) {
1302 Klass* k = Klass::cast((klassOop) obj);
1303 if (k->oop_is_instance()) {
1304 instanceKlass* ik = (instanceKlass*) k;
1305 // Link the class to cause the bytecodes to be rewritten and the
1306 // cpcache to be created.
1307 if (ik->get_init_state() < instanceKlass::linked) {
1308 ik->link_class(THREAD);
1309 guarantee(!HAS_PENDING_EXCEPTION, "exception in class rewriting");
1310 }
1311
1312 // Create String objects from string initializer symbols.
1313 ik->constants()->resolve_string_constants(THREAD);
1314 guarantee(!HAS_PENDING_EXCEPTION, "exception resolving string constants");
1315 }
1316 }
1317 }
1318 };
1319
1320
1321 // Support for a simple checksum of the contents of the class list
1322 // file to prevent trivial tampering. The algorithm matches that in
1323 // the MakeClassList program used by the J2SE build process.
1324 #define JSUM_SEED ((jlong)CONST64(0xcafebabebabecafe))
1325 static jlong
1326 jsum(jlong start, const char *buf, const int len)
1327 {
1328 jlong h = start;
1329 char *p = (char *)buf, *e = p + len;
1330 while (p < e) {
1331 char c = *p++;
1332 if (c <= ' ') {
1333 /* Skip spaces and control characters */
1334 continue;
1335 }
1336 h = 31 * h + c;
1337 }
1338 return h;
1339 }
1340
1341
1342
1343
1344
1345 // Preload classes from a list, populate the shared spaces and dump to a
1346 // file.
1347
1348 void GenCollectedHeap::preload_and_dump(TRAPS) {
1349 TraceTime timer("Dump Shared Spaces", TraceStartupTime);
1350 ResourceMark rm;
1351
1352 // Preload classes to be shared.
1353 // Should use some hpi:: method rather than fopen() here. aB.
1354 // Construct the path to the class list (in jre/lib)
1355 // Walk up two directories from the location of the VM and
1356 // optionally tack on "lib" (depending on platform)
1357 char class_list_path[JVM_MAXPATHLEN];
1358 os::jvm_path(class_list_path, sizeof(class_list_path));
1359 for (int i = 0; i < 3; i++) {
1360 char *end = strrchr(class_list_path, *os::file_separator());
1361 if (end != NULL) *end = '\0';
1362 }
1363 int class_list_path_len = (int)strlen(class_list_path);
1364 if (class_list_path_len >= 3) {
1365 if (strcmp(class_list_path + class_list_path_len - 3, "lib") != 0) {
1366 strcat(class_list_path, os::file_separator());
1367 strcat(class_list_path, "lib");
1368 }
1369 }
1370 strcat(class_list_path, os::file_separator());
1371 strcat(class_list_path, "classlist");
1372
1373 FILE* file = fopen(class_list_path, "r");
1374 if (file != NULL) {
1375 jlong computed_jsum = JSUM_SEED;
1376 jlong file_jsum = 0;
1377
1378 char class_name[256];
1379 int class_count = 0;
1380 GenCollectedHeap* gch = GenCollectedHeap::heap();
1381 gch->_preloading_shared_classes = true;
1382 GrowableArray<oop>* class_promote_order = new GrowableArray<oop>();
1383
1384 // Preload (and intern) strings which will be used later.
1385
1386 StringTable::intern("main", THREAD);
1387 StringTable::intern("([Ljava/lang/String;)V", THREAD);
1388 StringTable::intern("Ljava/lang/Class;", THREAD);
1389
1390 StringTable::intern("I", THREAD); // Needed for StringBuffer persistence?
1391 StringTable::intern("Z", THREAD); // Needed for StringBuffer persistence?
1392
1393 // sun.io.Converters
1394 static const char obj_array_sig[] = "[[Ljava/lang/Object;";
1395 SymbolTable::lookup(obj_array_sig, (int)strlen(obj_array_sig), THREAD);
1396
1397 // java.util.HashMap
1398 static const char map_entry_array_sig[] = "[Ljava/util/Map$Entry;";
1399 SymbolTable::lookup(map_entry_array_sig, (int)strlen(map_entry_array_sig),
1400 THREAD);
1401
1402 tty->print("Loading classes to share ... ");
1403 while ((fgets(class_name, sizeof class_name, file)) != NULL) {
1404 if (*class_name == '#') {
1405 jint fsh, fsl;
1406 if (sscanf(class_name, "# %8x%8x\n", &fsh, &fsl) == 2) {
1407 file_jsum = ((jlong)(fsh) << 32) | (fsl & 0xffffffff);
1408 }
1409
1410 continue;
1411 }
1412 // Remove trailing newline
1413 size_t name_len = strlen(class_name);
1414 class_name[name_len-1] = '\0';
1415
1416 computed_jsum = jsum(computed_jsum, class_name, (const int)name_len - 1);
1417
1418 // Got a class name - load it.
1419 symbolHandle class_name_symbol = oopFactory::new_symbol(class_name,
1420 THREAD);
1421 guarantee(!HAS_PENDING_EXCEPTION, "Exception creating a symbol.");
1422 klassOop klass = SystemDictionary::resolve_or_null(class_name_symbol,
1423 THREAD);
1424 guarantee(!HAS_PENDING_EXCEPTION, "Exception resolving a class.");
1425 if (klass != NULL) {
1426 if (PrintSharedSpaces) {
1427 tty->print_cr("Shared spaces preloaded: %s", class_name);
1428 }
1429
1430
1431 instanceKlass* ik = instanceKlass::cast(klass);
1432
1433 // Should be class load order as per -XX:+TraceClassLoadingPreorder
1434 class_promote_order->append(ik->as_klassOop());
1435
1436 // Link the class to cause the bytecodes to be rewritten and the
1437 // cpcache to be created. The linking is done as soon as classes
1438 // are loaded in order that the related data structures (klass,
1439 // cpCache, Sting constants) are located together.
1440
1441 if (ik->get_init_state() < instanceKlass::linked) {
1442 ik->link_class(THREAD);
1443 guarantee(!(HAS_PENDING_EXCEPTION), "exception in class rewriting");
1444 }
1445
1446 // Create String objects from string initializer symbols.
1447
1448 ik->constants()->resolve_string_constants(THREAD);
1449
1450 class_count++;
1451 } else {
1452 if (PrintSharedSpaces) {
1453 tty->cr();
1454 tty->print_cr(" Preload failed: %s", class_name);
1455 }
1456 }
1457 file_jsum = 0; // Checksum must be on last line of file
1458 }
1459 if (computed_jsum != file_jsum) {
1460 tty->cr();
1461 tty->print_cr("Preload failed: checksum of class list was incorrect.");
1462 exit(1);
1463 }
1464
1465 tty->print_cr("done. ");
1466
1467 if (PrintSharedSpaces) {
1468 tty->print_cr("Shared spaces: preloaded %d classes", class_count);
1469 }
1470
1471 // Rewrite and unlink classes.
1472 tty->print("Rewriting and unlinking classes ... ");
1473 // Make heap parsable
1474 ensure_parsability(false); // arg is actually don't care
1475
1476 // Link any classes which got missed. (It's not quite clear why
1477 // they got missed.) This iteration would be unsafe if we weren't
1478 // single-threaded at this point; however we can't do it on the VM
1479 // thread because it requires object allocation.
1480 LinkClassesClosure lcc(Thread::current());
1481 object_iterate(&lcc);
1482 tty->print_cr("done. ");
1483
1484 // Create and dump the shared spaces.
1485 jint err = CompactingPermGenGen::dump_shared(class_promote_order, THREAD);
1486 if (err != JNI_OK) {
1487 fatal("Dumping shared spaces failed.");
1488 }
1489
1490 } else {
1491 char errmsg[JVM_MAXPATHLEN];
1492 hpi::lasterror(errmsg, JVM_MAXPATHLEN);
1493 tty->print_cr("Loading classlist failed: %s", errmsg);
1494 exit(1);
1495 }
1496
1497 // Since various initialization steps have been undone by this process,
1498 // it is not reasonable to continue running a java process.
1499 exit(0);
1500 }