1 /*
2 * Copyright (c) 2003, 2010, 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/javaClasses.hpp"
27 #include "classfile/loaderConstraints.hpp"
28 #include "classfile/symbolTable.hpp"
29 #include "classfile/systemDictionary.hpp"
30 #include "gc_implementation/shared/spaceDecorator.hpp"
31 #include "memory/classify.hpp"
32 #include "memory/filemap.hpp"
33 #include "memory/oopFactory.hpp"
34 #include "memory/resourceArea.hpp"
35 #include "oops/methodDataOop.hpp"
36 #include "oops/oop.inline.hpp"
37 #include "runtime/javaCalls.hpp"
38 #include "runtime/signature.hpp"
39 #include "runtime/vmThread.hpp"
40 #include "runtime/vm_operations.hpp"
41 #include "utilities/copy.hpp"
42
43
44 // Closure to set up the fingerprint field for all methods.
45
46 class FingerprintMethodsClosure: public ObjectClosure {
47 public:
48 void do_object(oop obj) {
49 if (obj->is_method()) {
50 methodOop mobj = (methodOop)obj;
51 ResourceMark rm;
52 (new Fingerprinter(mobj))->fingerprint();
53 }
54 }
55 };
56
57
58
59 // Closure to set the hash value (String.hash field) in all of the
60 // String objects in the heap. Setting the hash value is not required.
61 // However, setting the value in advance prevents the value from being
62 // written later, increasing the likelihood that the shared page contain
63 // the hash can be shared.
64 //
65 // NOTE THAT the algorithm in StringTable::hash_string() MUST MATCH the
66 // algorithm in java.lang.String.hashCode().
67
68 class StringHashCodeClosure: public OopClosure {
69 private:
70 Thread* THREAD;
71 int hash_offset;
72 public:
73 StringHashCodeClosure(Thread* t) {
74 THREAD = t;
75 hash_offset = java_lang_String::hash_offset_in_bytes();
76 }
77
78 void do_oop(oop* p) {
79 if (p != NULL) {
80 oop obj = *p;
81 if (obj->klass() == SystemDictionary::String_klass()) {
82
83 int hash;
84 typeArrayOop value = java_lang_String::value(obj);
85 int length = java_lang_String::length(obj);
86 if (length == 0) {
87 hash = 0;
88 } else {
89 int offset = java_lang_String::offset(obj);
90 jchar* s = value->char_at_addr(offset);
91 hash = StringTable::hash_string(s, length);
92 }
93 obj->int_field_put(hash_offset, hash);
94 }
95 }
96 }
97 void do_oop(narrowOop* p) { ShouldNotReachHere(); }
98 };
99
100
101 // Remove data from objects which should not appear in the shared file
102 // (as it pertains only to the current JVM).
103
104 class RemoveUnshareableInfoClosure : public ObjectClosure {
105 public:
106 void do_object(oop obj) {
107 // Zap data from the objects which is pertains only to this JVM. We
108 // want that data recreated in new JVMs when the shared file is used.
109 if (obj->is_method()) {
110 ((methodOop)obj)->remove_unshareable_info();
111 }
112 else if (obj->is_klass()) {
113 Klass::cast((klassOop)obj)->remove_unshareable_info();
114 }
115
116 // Don't save compiler related special oops (shouldn't be any yet).
117 if (obj->is_methodData() || obj->is_compiledICHolder()) {
118 ShouldNotReachHere();
119 }
120 }
121 };
122
123
124 static bool mark_object(oop obj) {
125 if (obj != NULL &&
126 !obj->is_shared() &&
127 !obj->is_forwarded() &&
128 !obj->is_gc_marked()) {
129 obj->set_mark(markOopDesc::prototype()->set_marked());
130 return true;
131 }
132
133 return false;
134 }
135
136 // Closure: mark objects closure.
137
138 class MarkObjectsOopClosure : public OopClosure {
139 public:
140 void do_oop(oop* p) { mark_object(*p); }
141 void do_oop(narrowOop* p) { ShouldNotReachHere(); }
142 };
143
144
145 class MarkObjectsSkippingKlassesOopClosure : public OopClosure {
146 public:
147 void do_oop(oop* pobj) {
148 oop obj = *pobj;
149 if (obj != NULL &&
150 !obj->is_klass()) {
151 mark_object(obj);
152 }
153 }
154 void do_oop(narrowOop* pobj) { ShouldNotReachHere(); }
155 };
156
157
158 static void mark_object_recursive_skipping_klasses(oop obj) {
159 mark_object(obj);
160 if (obj != NULL) {
161 MarkObjectsSkippingKlassesOopClosure mark_all;
162 obj->oop_iterate(&mark_all);
163 }
164 }
165
166
167 // Closure: mark common read-only objects, excluding symbols
168
169 class MarkCommonReadOnly : public ObjectClosure {
170 private:
171 MarkObjectsOopClosure mark_all;
172 public:
173 void do_object(oop obj) {
174
175 // Mark all constMethod objects.
176
177 if (obj->is_constMethod()) {
178 mark_object(obj);
179 mark_object(constMethodOop(obj)->stackmap_data());
180 // Exception tables are needed by ci code during compilation.
181 mark_object(constMethodOop(obj)->exception_table());
182 }
183
184 // Mark objects referenced by klass objects which are read-only.
185
186 else if (obj->is_klass()) {
187 Klass* k = Klass::cast((klassOop)obj);
188 mark_object(k->secondary_supers());
189
190 // The METHODS() OBJARRAYS CANNOT BE MADE READ-ONLY, even though
191 // it is never modified. Otherwise, they will be pre-marked; the
192 // GC marking phase will skip them; and by skipping them will fail
193 // to mark the methods objects referenced by the array.
194
195 if (obj->blueprint()->oop_is_instanceKlass()) {
196 instanceKlass* ik = instanceKlass::cast((klassOop)obj);
197 mark_object(ik->method_ordering());
198 mark_object(ik->local_interfaces());
199 mark_object(ik->transitive_interfaces());
200 mark_object(ik->fields());
201
202 mark_object(ik->class_annotations());
203
204 mark_object_recursive_skipping_klasses(ik->fields_annotations());
205 mark_object_recursive_skipping_klasses(ik->methods_annotations());
206 mark_object_recursive_skipping_klasses(ik->methods_parameter_annotations());
207 mark_object_recursive_skipping_klasses(ik->methods_default_annotations());
208
209 typeArrayOop inner_classes = ik->inner_classes();
210 if (inner_classes != NULL) {
211 mark_object(inner_classes);
212 }
213 }
214 }
215 }
216 };
217
218
219 // Closure: mark common symbols
220
221 class MarkCommonSymbols : public ObjectClosure {
222 private:
223 MarkObjectsOopClosure mark_all;
224 public:
225 void do_object(oop obj) {
226
227 // Mark symbols refered to by method objects.
228
229 if (obj->is_method()) {
230 methodOop m = methodOop(obj);
231 mark_object(m->name());
232 mark_object(m->signature());
233 }
234
235 // Mark symbols referenced by klass objects which are read-only.
236
237 else if (obj->is_klass()) {
238
239 if (obj->blueprint()->oop_is_instanceKlass()) {
240 instanceKlass* ik = instanceKlass::cast((klassOop)obj);
241 mark_object(ik->name());
242 mark_object(ik->generic_signature());
243 mark_object(ik->source_file_name());
244 mark_object(ik->source_debug_extension());
245
246 typeArrayOop inner_classes = ik->inner_classes();
247 if (inner_classes != NULL) {
248 int length = inner_classes->length();
249 for (int i = 0;
250 i < length;
251 i += instanceKlass::inner_class_next_offset) {
252 int ioff = i + instanceKlass::inner_class_inner_name_offset;
253 int index = inner_classes->ushort_at(ioff);
254 if (index != 0) {
255 mark_object(ik->constants()->symbol_at(index));
256 }
257 }
258 }
259 ik->field_names_and_sigs_iterate(&mark_all);
260 }
261 }
262
263 // Mark symbols referenced by other constantpool entries.
264
265 if (obj->is_constantPool()) {
266 constantPoolOop(obj)->shared_symbols_iterate(&mark_all);
267 }
268 }
269 };
270
271
272 // Closure: mark char arrays used by strings
273
274 class MarkStringValues : public ObjectClosure {
275 private:
276 MarkObjectsOopClosure mark_all;
277 public:
278 void do_object(oop obj) {
279
280 // Character arrays referenced by String objects are read-only.
281
282 if (java_lang_String::is_instance(obj)) {
283 mark_object(java_lang_String::value(obj));
284 }
285 }
286 };
287
288
289 #ifdef DEBUG
290 // Closure: Check for objects left in the heap which have not been moved.
291
292 class CheckRemainingObjects : public ObjectClosure {
293 private:
294 int count;
295
296 public:
297 CheckRemainingObjects() {
298 count = 0;
299 }
300
301 void do_object(oop obj) {
302 if (!obj->is_shared() &&
303 !obj->is_forwarded()) {
304 ++count;
305 if (Verbose) {
306 tty->print("Unreferenced object: ");
307 obj->print_on(tty);
308 }
309 }
310 }
311
312 void status() {
313 tty->print_cr("%d objects no longer referenced, not shared.", count);
314 }
315 };
316 #endif
317
318
319 // Closure: Mark remaining objects read-write, except Strings.
320
321 class MarkReadWriteObjects : public ObjectClosure {
322 private:
323 MarkObjectsOopClosure mark_objects;
324 public:
325 void do_object(oop obj) {
326
327 // The METHODS() OBJARRAYS CANNOT BE MADE READ-ONLY, even though
328 // it is never modified. Otherwise, they will be pre-marked; the
329 // GC marking phase will skip them; and by skipping them will fail
330 // to mark the methods objects referenced by the array.
331
332 if (obj->is_klass()) {
333 mark_object(obj);
334 Klass* k = klassOop(obj)->klass_part();
335 mark_object(k->java_mirror());
336 if (obj->blueprint()->oop_is_instanceKlass()) {
337 instanceKlass* ik = (instanceKlass*)k;
338 mark_object(ik->methods());
339 mark_object(ik->constants());
340 }
341 if (obj->blueprint()->oop_is_javaArray()) {
342 arrayKlass* ak = (arrayKlass*)k;
343 mark_object(ak->component_mirror());
344 }
345 return;
346 }
347
348 // Mark constantPool tags and the constantPoolCache.
349
350 else if (obj->is_constantPool()) {
351 constantPoolOop pool = constantPoolOop(obj);
352 mark_object(pool->cache());
353 pool->shared_tags_iterate(&mark_objects);
354 return;
355 }
356
357 // Mark all method objects.
358
359 if (obj->is_method()) {
360 mark_object(obj);
361 }
362 }
363 };
364
365
366 // Closure: Mark String objects read-write.
367
368 class MarkStringObjects : public ObjectClosure {
369 private:
370 MarkObjectsOopClosure mark_objects;
371 public:
372 void do_object(oop obj) {
373
374 // Mark String objects referenced by constant pool entries.
375
376 if (obj->is_constantPool()) {
377 constantPoolOop pool = constantPoolOop(obj);
378 pool->shared_strings_iterate(&mark_objects);
379 return;
380 }
381 }
382 };
383
384
385 // Move objects matching specified type (ie. lock_bits) to the specified
386 // space.
387
388 class MoveMarkedObjects : public ObjectClosure {
389 private:
390 OffsetTableContigSpace* _space;
391 bool _read_only;
392
393 public:
394 MoveMarkedObjects(OffsetTableContigSpace* space, bool read_only) {
395 _space = space;
396 _read_only = read_only;
397 }
398
399 void do_object(oop obj) {
400 if (obj->is_shared()) {
401 return;
402 }
403 if (obj->is_gc_marked() && obj->forwardee() == NULL) {
404 int s = obj->size();
405 oop sh_obj = (oop)_space->allocate(s);
406 if (sh_obj == NULL) {
407 if (_read_only) {
408 warning("\nThe permanent generation read only space is not large "
409 "enough to \npreload requested classes. Use "
410 "-XX:SharedReadOnlySize= to increase \nthe initial "
411 "size of the read only space.\n");
412 } else {
413 warning("\nThe permanent generation read write space is not large "
414 "enough to \npreload requested classes. Use "
415 "-XX:SharedReadWriteSize= to increase \nthe initial "
416 "size of the read write space.\n");
417 }
418 exit(2);
419 }
420 if (PrintSharedSpaces && Verbose && WizardMode) {
421 tty->print_cr("\nMoveMarkedObjects: " PTR_FORMAT " -> " PTR_FORMAT " %s", obj, sh_obj,
422 (_read_only ? "ro" : "rw"));
423 }
424 Copy::aligned_disjoint_words((HeapWord*)obj, (HeapWord*)sh_obj, s);
425 obj->forward_to(sh_obj);
426 if (_read_only) {
427 // Readonly objects: set hash value to self pointer and make gc_marked.
428 sh_obj->forward_to(sh_obj);
429 } else {
430 sh_obj->init_mark();
431 }
432 }
433 }
434 };
435
436 static void mark_and_move(oop obj, MoveMarkedObjects* move) {
437 if (mark_object(obj)) move->do_object(obj);
438 }
439
440 enum order_policy {
441 OP_favor_startup = 0,
442 OP_balanced = 1,
443 OP_favor_runtime = 2
444 };
445
446 static void mark_and_move_for_policy(order_policy policy, oop obj, MoveMarkedObjects* move) {
447 if (SharedOptimizeColdStartPolicy >= policy) mark_and_move(obj, move);
448 }
449
450 class MarkAndMoveOrderedReadOnly : public ObjectClosure {
451 private:
452 MoveMarkedObjects *_move_ro;
453
454 public:
455 MarkAndMoveOrderedReadOnly(MoveMarkedObjects *move_ro) : _move_ro(move_ro) {}
456
457 void do_object(oop obj) {
458 if (obj->is_klass() && obj->blueprint()->oop_is_instanceKlass()) {
459 instanceKlass* ik = instanceKlass::cast((klassOop)obj);
460 int i;
461
462 mark_and_move_for_policy(OP_favor_startup, ik->name(), _move_ro);
463
464 if (ik->super() != NULL) {
465 do_object(ik->super());
466 }
467
468 objArrayOop interfaces = ik->local_interfaces();
469 mark_and_move_for_policy(OP_favor_startup, interfaces, _move_ro);
470 for(i = 0; i < interfaces->length(); i++) {
471 klassOop k = klassOop(interfaces->obj_at(i));
472 mark_and_move_for_policy(OP_favor_startup, k->klass_part()->name(), _move_ro);
473 do_object(k);
474 }
475
476 objArrayOop methods = ik->methods();
477 for(i = 0; i < methods->length(); i++) {
478 methodOop m = methodOop(methods->obj_at(i));
479 mark_and_move_for_policy(OP_favor_startup, m->constMethod(), _move_ro);
480 mark_and_move_for_policy(OP_favor_runtime, m->constMethod()->exception_table(), _move_ro);
481 mark_and_move_for_policy(OP_favor_runtime, m->constMethod()->stackmap_data(), _move_ro);
482
483 // We don't move the name symbolOop here because it may invalidate
484 // method ordering, which is dependent on the address of the name
485 // symbolOop. It will get promoted later with the other symbols.
486 // Method name is rarely accessed during classloading anyway.
487 // mark_and_move_for_policy(OP_balanced, m->name(), _move_ro);
488
489 mark_and_move_for_policy(OP_favor_startup, m->signature(), _move_ro);
490 }
491
492 mark_and_move_for_policy(OP_favor_startup, ik->transitive_interfaces(), _move_ro);
493 mark_and_move_for_policy(OP_favor_startup, ik->fields(), _move_ro);
494
495 mark_and_move_for_policy(OP_favor_runtime, ik->secondary_supers(), _move_ro);
496 mark_and_move_for_policy(OP_favor_runtime, ik->method_ordering(), _move_ro);
497 mark_and_move_for_policy(OP_favor_runtime, ik->class_annotations(), _move_ro);
498 mark_and_move_for_policy(OP_favor_runtime, ik->fields_annotations(), _move_ro);
499 mark_and_move_for_policy(OP_favor_runtime, ik->methods_annotations(), _move_ro);
500 mark_and_move_for_policy(OP_favor_runtime, ik->methods_parameter_annotations(), _move_ro);
501 mark_and_move_for_policy(OP_favor_runtime, ik->methods_default_annotations(), _move_ro);
502 mark_and_move_for_policy(OP_favor_runtime, ik->inner_classes(), _move_ro);
503 mark_and_move_for_policy(OP_favor_runtime, ik->secondary_supers(), _move_ro);
504 }
505 }
506 };
507
508 class MarkAndMoveOrderedReadWrite: public ObjectClosure {
509 private:
510 MoveMarkedObjects *_move_rw;
511
512 public:
513 MarkAndMoveOrderedReadWrite(MoveMarkedObjects *move_rw) : _move_rw(move_rw) {}
514
515 void do_object(oop obj) {
516 if (obj->is_klass() && obj->blueprint()->oop_is_instanceKlass()) {
517 instanceKlass* ik = instanceKlass::cast((klassOop)obj);
518 int i;
519
520 mark_and_move_for_policy(OP_favor_startup, ik->as_klassOop(), _move_rw);
521
522 if (ik->super() != NULL) {
523 do_object(ik->super());
524 }
525
526 objArrayOop interfaces = ik->local_interfaces();
527 for(i = 0; i < interfaces->length(); i++) {
528 klassOop k = klassOop(interfaces->obj_at(i));
529 mark_and_move_for_policy(OP_favor_startup, k, _move_rw);
530 do_object(k);
531 }
532
533 objArrayOop methods = ik->methods();
534 mark_and_move_for_policy(OP_favor_startup, methods, _move_rw);
535 for(i = 0; i < methods->length(); i++) {
536 methodOop m = methodOop(methods->obj_at(i));
537 mark_and_move_for_policy(OP_favor_startup, m, _move_rw);
538 mark_and_move_for_policy(OP_favor_startup, ik->constants(), _move_rw); // idempotent
539 mark_and_move_for_policy(OP_balanced, ik->constants()->cache(), _move_rw); // idempotent
540 mark_and_move_for_policy(OP_balanced, ik->constants()->tags(), _move_rw); // idempotent
541 }
542
543 mark_and_move_for_policy(OP_favor_startup, ik->as_klassOop()->klass(), _move_rw);
544 mark_and_move_for_policy(OP_favor_startup, ik->constants()->klass(), _move_rw);
545
546 // Although Java mirrors are marked in MarkReadWriteObjects,
547 // apparently they were never moved into shared spaces since
548 // MoveMarkedObjects skips marked instance oops. This may
549 // be a bug in the original implementation or simply the vestige
550 // of an abandoned experiment. Nevertheless we leave a hint
551 // here in case this capability is ever correctly implemented.
552 //
553 // mark_and_move_for_policy(OP_favor_runtime, ik->java_mirror(), _move_rw);
554 }
555 }
556
557 };
558
559 // Adjust references in oops to refer to shared spaces.
560
561 class ResolveForwardingClosure: public OopClosure {
562 public:
563 void do_oop(oop* p) {
564 oop obj = *p;
565 if (!obj->is_shared()) {
566 if (obj != NULL) {
567 oop f = obj->forwardee();
568 guarantee(f->is_shared(), "Oop doesn't refer to shared space.");
569 *p = f;
570 }
571 }
572 }
573 void do_oop(narrowOop* pobj) { ShouldNotReachHere(); }
574 };
575
576
577 void sort_methods(instanceKlass* ik, TRAPS) {
578 klassOop super = ik->super();
579 if (super != NULL) {
580 sort_methods(instanceKlass::cast(super), THREAD);
581 }
582
583 // The methods array must be ordered by symbolOop address. (See
584 // classFileParser.cpp where methods in a class are originally
585 // sorted.) Since objects have just be reordered, this must be
586 // corrected.
587 methodOopDesc::sort_methods(ik->methods(),
588 ik->methods_annotations(),
589 ik->methods_parameter_annotations(),
590 ik->methods_default_annotations(),
591 true /* idempotent, slow */);
592
593 // Itable indices are calculated based on methods array order
594 // (see klassItable::compute_itable_index()). Must reinitialize.
595 // We assume that since checkconstraints is false, this method
596 // cannot throw an exception. An exception here would be
597 // problematic since this is the VMThread, not a JavaThread.
598 ik->itable()->initialize_itable(false, THREAD);
599 }
600
601 // Sort methods if the oop is an instanceKlass.
602
603 class SortMethodsClosure: public ObjectClosure {
604 private:
605 Thread* _thread;
606
607 public:
608 SortMethodsClosure(Thread* thread) : _thread(thread) {}
609
610 void do_object(oop obj) {
611 // instanceKlass objects need some adjustment.
612 if (obj->blueprint()->oop_is_instanceKlass()) {
613 instanceKlass* ik = instanceKlass::cast((klassOop)obj);
614
615 sort_methods(ik, _thread);
616 }
617 }
618 };
619
620
621 // Adjust references in oops to refer to shared spaces.
622
623 class PatchOopsClosure: public ObjectClosure {
624 private:
625 Thread* _thread;
626 ResolveForwardingClosure resolve;
627
628 public:
629 PatchOopsClosure(Thread* thread) : _thread(thread) {}
630
631 void do_object(oop obj) {
632 obj->oop_iterate_header(&resolve);
633 obj->oop_iterate(&resolve);
634
635 assert(obj->klass()->is_shared(), "Klass not pointing into shared space.");
636
637 // If the object is a Java object or class which might (in the
638 // future) contain a reference to a young gen object, add it to the
639 // list.
640
641 if (obj->is_klass() || obj->is_instance()) {
642 if (obj->is_klass() ||
643 obj->is_a(SystemDictionary::Class_klass()) ||
644 obj->is_a(SystemDictionary::Throwable_klass())) {
645 // Do nothing
646 }
647 else if (obj->is_a(SystemDictionary::String_klass())) {
648 // immutable objects.
649 } else {
650 // someone added an object we hadn't accounted for.
651 ShouldNotReachHere();
652 }
653 }
654 }
655 };
656
657
658 // Empty the young and old generations.
659
660 class ClearSpaceClosure : public SpaceClosure {
661 public:
662 void do_space(Space* s) {
663 s->clear(SpaceDecorator::Mangle);
664 }
665 };
666
667
668 // Closure for serializing initialization data out to a data area to be
669 // written to the shared file.
670
671 class WriteClosure : public SerializeOopClosure {
672 private:
673 oop* top;
674 char* end;
675
676 void out_of_space() {
677 warning("\nThe shared miscellaneous data space is not large "
678 "enough to \npreload requested classes. Use "
679 "-XX:SharedMiscDataSize= to increase \nthe initial "
680 "size of the miscellaneous data space.\n");
681 exit(2);
682 }
683
684
685 inline void check_space() {
686 if ((char*)top + sizeof(oop) > end) {
687 out_of_space();
688 }
689 }
690
691
692 public:
693 WriteClosure(char* md_top, char* md_end) {
694 top = (oop*)md_top;
695 end = md_end;
696 }
697
698 char* get_top() { return (char*)top; }
699
700 void do_oop(oop* p) {
701 check_space();
702 oop obj = *p;
703 assert(obj->is_oop_or_null(), "invalid oop");
704 assert(obj == NULL || obj->is_shared(),
705 "Oop in shared space not pointing into shared space.");
706 *top = obj;
707 ++top;
708 }
709
710 void do_oop(narrowOop* pobj) { ShouldNotReachHere(); }
711
712 void do_int(int* p) {
713 check_space();
714 *top = (oop)(intptr_t)*p;
715 ++top;
716 }
717
718 void do_size_t(size_t* p) {
719 check_space();
720 *top = (oop)(intptr_t)*p;
721 ++top;
722 }
723
724 void do_ptr(void** p) {
725 check_space();
726 *top = (oop)*p;
727 ++top;
728 }
729
730 void do_ptr(HeapWord** p) { do_ptr((void **) p); }
731
732 void do_tag(int tag) {
733 check_space();
734 *top = (oop)(intptr_t)tag;
735 ++top;
736 }
737
738 void do_region(u_char* start, size_t size) {
739 if ((char*)top + size > end) {
740 out_of_space();
741 }
742 assert((intptr_t)start % sizeof(oop) == 0, "bad alignment");
743 assert(size % sizeof(oop) == 0, "bad size");
744 do_tag((int)size);
745 while (size > 0) {
746 *top = *(oop*)start;
747 ++top;
748 start += sizeof(oop);
749 size -= sizeof(oop);
750 }
751 }
752
753 bool reading() const { return false; }
754 };
755
756
757 class ResolveConstantPoolsClosure : public ObjectClosure {
758 private:
759 TRAPS;
760 public:
761 ResolveConstantPoolsClosure(Thread *t) {
762 __the_thread__ = t;
763 }
764 void do_object(oop obj) {
765 if (obj->is_constantPool()) {
766 constantPoolOop cpool = (constantPoolOop)obj;
767 int unresolved = cpool->pre_resolve_shared_klasses(THREAD);
768 }
769 }
770 };
771
772
773 // Print a summary of the contents of the read/write spaces to help
774 // identify objects which might be able to be made read-only. At this
775 // point, the objects have been written, and we can trash them as
776 // needed.
777
778 static void print_contents() {
779 if (PrintSharedSpaces) {
780 GenCollectedHeap* gch = GenCollectedHeap::heap();
781 CompactingPermGenGen* gen = (CompactingPermGenGen*)gch->perm_gen();
782
783 // High level summary of the read-only space:
784
785 ClassifyObjectClosure coc;
786 tty->cr(); tty->print_cr("ReadOnly space:");
787 gen->ro_space()->object_iterate(&coc);
788 coc.print();
789
790 // High level summary of the read-write space:
791
792 coc.reset();
793 tty->cr(); tty->print_cr("ReadWrite space:");
794 gen->rw_space()->object_iterate(&coc);
795 coc.print();
796
797 // Reset counters
798
799 ClearAllocCountClosure cacc;
800 gen->ro_space()->object_iterate(&cacc);
801 gen->rw_space()->object_iterate(&cacc);
802 coc.reset();
803
804 // Lower level summary of the read-only space:
805
806 gen->ro_space()->object_iterate(&coc);
807 tty->cr(); tty->print_cr("ReadOnly space:");
808 ClassifyInstanceKlassClosure cikc;
809 gen->rw_space()->object_iterate(&cikc);
810 cikc.print();
811
812 // Reset counters
813
814 gen->ro_space()->object_iterate(&cacc);
815 gen->rw_space()->object_iterate(&cacc);
816 coc.reset();
817
818 // Lower level summary of the read-write space:
819
820 gen->rw_space()->object_iterate(&coc);
821 cikc.reset();
822 tty->cr(); tty->print_cr("ReadWrite space:");
823 gen->rw_space()->object_iterate(&cikc);
824 cikc.print();
825 }
826 }
827
828
829 // Patch C++ vtable pointer in klass oops.
830
831 // Klass objects contain references to c++ vtables in the JVM library.
832 // Fix them to point to our constructed vtables. However, don't iterate
833 // across the space while doing this, as that causes the vtables to be
834 // patched, undoing our useful work. Instead, iterate to make a list,
835 // then use the list to do the fixing.
836 //
837 // Our constructed vtables:
838 // Dump time:
839 // 1. init_self_patching_vtbl_list: table of pointers to current virtual method addrs
840 // 2. generate_vtable_methods: create jump table, appended to above vtbl_list
841 // 3. PatchKlassVtables: for Klass list, patch the vtable entry to point to jump table
842 // rather than to current vtbl
843 // Table layout: NOTE FIXED SIZE
844 // 1. vtbl pointers
845 // 2. #Klass X #virtual methods per Klass
846 // 1 entry for each, in the order:
847 // Klass1:method1 entry, Klass1:method2 entry, ... Klass1:method<num_virtuals> entry
848 // Klass2:method1 entry, Klass2:method2 entry, ... Klass2:method<num_virtuals> entry
849 // ...
850 // Klass<vtbl_list_size>:method1 entry, Klass<vtbl_list_size>:method2 entry,
851 // ... Klass<vtbl_list_size>:method<num_virtuals> entry
852 // Sample entry: (Sparc):
853 // save(sp, -256, sp)
854 // ba,pt common_code
855 // mov XXX, %L0 %L0 gets: Klass index <<8 + method index (note: max method index 255)
856 //
857 // Restore time:
858 // 1. initialize_oops: reserve space for table
859 // 2. init_self_patching_vtbl_list: update pointers to NEW virtual method addrs in text
860 //
861 // Execution time:
862 // First virtual method call for any object of these Klass types:
863 // 1. object->klass->klass_part
864 // 2. vtable entry for that klass_part points to the jump table entries
865 // 3. branches to common_code with %O0/klass_part, %L0: Klass index <<8 + method index
866 // 4. common_code:
867 // Get address of new vtbl pointer for this Klass from updated table
868 // Update new vtbl pointer in the Klass: future virtual calls go direct
869 // Jump to method, using new vtbl pointer and method index
870
871 class PatchKlassVtables: public ObjectClosure {
872 private:
873 void* _vtbl_ptr;
874 VirtualSpace* _md_vs;
875 GrowableArray<klassOop>* _klass_objects;
876
877 public:
878
879 PatchKlassVtables(void* vtbl_ptr, VirtualSpace* md_vs) {
880 _vtbl_ptr = vtbl_ptr;
881 _md_vs = md_vs;
882 _klass_objects = new GrowableArray<klassOop>();
883 }
884
885
886 void do_object(oop obj) {
887 if (obj->is_klass()) {
888 _klass_objects->append(klassOop(obj));
889 }
890 }
891
892
893 void patch(void** vtbl_list, int vtbl_list_size) {
894 for (int i = 0; i < _klass_objects->length(); ++i) {
895 klassOop obj = (klassOop)_klass_objects->at(i);
896 Klass* k = obj->klass_part();
897 void* v = *(void**)k;
898
899 int n;
900 for (n = 0; n < vtbl_list_size; ++n) {
901 *(void**)k = NULL;
902 if (vtbl_list[n] == v) {
903 *(void**)k = (void**)_vtbl_ptr +
904 (n * CompactingPermGenGen::num_virtuals);
905 break;
906 }
907 }
908 guarantee(n < vtbl_list_size, "unable to find matching vtbl pointer");
909 }
910 }
911 };
912
913
914 // Populate the shared space.
915
916 class VM_PopulateDumpSharedSpace: public VM_Operation {
917 private:
918 GrowableArray<oop> *_class_promote_order;
919 OffsetTableContigSpace* _ro_space;
920 OffsetTableContigSpace* _rw_space;
921 VirtualSpace* _md_vs;
922 VirtualSpace* _mc_vs;
923
924 public:
925 VM_PopulateDumpSharedSpace(GrowableArray<oop> *class_promote_order,
926 OffsetTableContigSpace* ro_space,
927 OffsetTableContigSpace* rw_space,
928 VirtualSpace* md_vs, VirtualSpace* mc_vs) {
929 _class_promote_order = class_promote_order;
930 _ro_space = ro_space;
931 _rw_space = rw_space;
932 _md_vs = md_vs;
933 _mc_vs = mc_vs;
934 }
935
936 VMOp_Type type() const { return VMOp_PopulateDumpSharedSpace; }
937 void doit() {
938 Thread* THREAD = VMThread::vm_thread();
939 NOT_PRODUCT(SystemDictionary::verify();)
940 // The following guarantee is meant to ensure that no loader constraints
941 // exist yet, since the constraints table is not shared. This becomes
942 // more important now that we don't re-initialize vtables/itables for
943 // shared classes at runtime, where constraints were previously created.
944 guarantee(SystemDictionary::constraints()->number_of_entries() == 0,
945 "loader constraints are not saved");
946 // Revisit and implement this if we prelink method handle call sites:
947 guarantee(SystemDictionary::invoke_method_table() == NULL ||
948 SystemDictionary::invoke_method_table()->number_of_entries() == 0,
949 "invoke method table is not saved");
950 GenCollectedHeap* gch = GenCollectedHeap::heap();
951
952 // At this point, many classes have been loaded.
953
954 // Update all the fingerprints in the shared methods.
955
956 tty->print("Calculating fingerprints ... ");
957 FingerprintMethodsClosure fpmc;
958 gch->object_iterate(&fpmc);
959 tty->print_cr("done. ");
960
961 // Remove all references outside the heap.
962
963 tty->print("Removing unshareable information ... ");
964 RemoveUnshareableInfoClosure ruic;
965 gch->object_iterate(&ruic);
966 tty->print_cr("done. ");
967
968 // Move the objects in three passes.
969
970 MarkObjectsOopClosure mark_all;
971 MarkCommonReadOnly mark_common_ro;
972 MarkCommonSymbols mark_common_symbols;
973 MarkStringValues mark_string_values;
974 MarkReadWriteObjects mark_rw;
975 MarkStringObjects mark_strings;
976 MoveMarkedObjects move_ro(_ro_space, true);
977 MoveMarkedObjects move_rw(_rw_space, false);
978
979 // The SharedOptimizeColdStart VM option governs the new layout
980 // algorithm for promoting classes into the shared archive.
981 // The general idea is to minimize cold start time by laying
982 // out the objects in the order they are accessed at startup time.
983 // By doing this we are trying to eliminate out-of-order accesses
984 // in the shared archive. This benefits cold startup time by making
985 // disk reads as sequential as possible during class loading and
986 // bootstrapping activities. There may also be a small secondary
987 // effect of better "packing" of more commonly used data on a smaller
988 // number of pages, although no direct benefit has been measured from
989 // this effect.
990 //
991 // At the class level of granularity, the promotion order is dictated
992 // by the classlist file whose generation is discussed elsewhere.
993 //
994 // At smaller granularity, optimal ordering was determined by an
995 // offline analysis of object access order in the shared archive.
996 // The dbx watchpoint facility, combined with SA post-processing,
997 // was used to observe common access patterns primarily during
998 // classloading. This information was used to craft the promotion
999 // order seen in the following closures.
1000 //
1001 // The observed access order is mostly governed by what happens
1002 // in SystemDictionary::load_shared_class(). NOTE WELL - care
1003 // should be taken when making changes to this method, because it
1004 // may invalidate assumptions made about access order!
1005 //
1006 // (Ideally, there would be a better way to manage changes to
1007 // the access order. Unfortunately a generic in-VM solution for
1008 // dynamically observing access order and optimizing shared
1009 // archive layout is pretty difficult. We go with the static
1010 // analysis because the code is fairly mature at this point
1011 // and we're betting that the access order won't change much.)
1012
1013 MarkAndMoveOrderedReadOnly mark_and_move_ordered_ro(&move_ro);
1014 MarkAndMoveOrderedReadWrite mark_and_move_ordered_rw(&move_rw);
1015
1016 // Phase 1a: move commonly used read-only objects to the read-only space.
1017
1018 if (SharedOptimizeColdStart) {
1019 tty->print("Moving pre-ordered read-only objects to shared space at " PTR_FORMAT " ... ",
1020 _ro_space->top());
1021 for (int i = 0; i < _class_promote_order->length(); i++) {
1022 oop obj = _class_promote_order->at(i);
1023 mark_and_move_ordered_ro.do_object(obj);
1024 }
1025 tty->print_cr("done. ");
1026 }
1027
1028 tty->print("Moving read-only objects to shared space at " PTR_FORMAT " ... ",
1029 _ro_space->top());
1030 gch->object_iterate(&mark_common_ro);
1031 gch->object_iterate(&move_ro);
1032 tty->print_cr("done. ");
1033
1034 // Phase 1b: move commonly used symbols to the read-only space.
1035
1036 tty->print("Moving common symbols to shared space at " PTR_FORMAT " ... ",
1037 _ro_space->top());
1038 gch->object_iterate(&mark_common_symbols);
1039 gch->object_iterate(&move_ro);
1040 tty->print_cr("done. ");
1041
1042 // Phase 1c: move remaining symbols to the read-only space
1043 // (e.g. String initializers).
1044
1045 tty->print("Moving remaining symbols to shared space at " PTR_FORMAT " ... ",
1046 _ro_space->top());
1047 vmSymbols::oops_do(&mark_all, true);
1048 gch->object_iterate(&move_ro);
1049 tty->print_cr("done. ");
1050
1051 // Phase 1d: move String character arrays to the read-only space.
1052
1053 tty->print("Moving string char arrays to shared space at " PTR_FORMAT " ... ",
1054 _ro_space->top());
1055 gch->object_iterate(&mark_string_values);
1056 gch->object_iterate(&move_ro);
1057 tty->print_cr("done. ");
1058
1059 // Phase 2: move all remaining symbols to the read-only space. The
1060 // remaining symbols are assumed to be string initializers no longer
1061 // referenced.
1062
1063 void* extra_symbols = _ro_space->top();
1064 tty->print("Moving additional symbols to shared space at " PTR_FORMAT " ... ",
1065 _ro_space->top());
1066 SymbolTable::oops_do(&mark_all);
1067 gch->object_iterate(&move_ro);
1068 tty->print_cr("done. ");
1069 tty->print_cr("Read-only space ends at " PTR_FORMAT ", %d bytes.",
1070 _ro_space->top(), _ro_space->used());
1071
1072 // Phase 3: move read-write objects to the read-write space, except
1073 // Strings.
1074
1075 if (SharedOptimizeColdStart) {
1076 tty->print("Moving pre-ordered read-write objects to shared space at " PTR_FORMAT " ... ",
1077 _rw_space->top());
1078 for (int i = 0; i < _class_promote_order->length(); i++) {
1079 oop obj = _class_promote_order->at(i);
1080 mark_and_move_ordered_rw.do_object(obj);
1081 }
1082 tty->print_cr("done. ");
1083 }
1084 tty->print("Moving read-write objects to shared space at " PTR_FORMAT " ... ",
1085 _rw_space->top());
1086 Universe::oops_do(&mark_all, true);
1087 SystemDictionary::oops_do(&mark_all);
1088 oop tmp = Universe::arithmetic_exception_instance();
1089 mark_object(java_lang_Throwable::message(tmp));
1090 gch->object_iterate(&mark_rw);
1091 gch->object_iterate(&move_rw);
1092 tty->print_cr("done. ");
1093
1094 // Phase 4: move String objects to the read-write space.
1095
1096 tty->print("Moving String objects to shared space at " PTR_FORMAT " ... ",
1097 _rw_space->top());
1098 StringTable::oops_do(&mark_all);
1099 gch->object_iterate(&mark_strings);
1100 gch->object_iterate(&move_rw);
1101 tty->print_cr("done. ");
1102 tty->print_cr("Read-write space ends at " PTR_FORMAT ", %d bytes.",
1103 _rw_space->top(), _rw_space->used());
1104
1105 #ifdef DEBUG
1106 // Check: scan for objects which were not moved.
1107
1108 CheckRemainingObjects check_objects;
1109 gch->object_iterate(&check_objects);
1110 check_objects.status();
1111 #endif
1112
1113 // Resolve forwarding in objects and saved C++ structures
1114 tty->print("Updating references to shared objects ... ");
1115 ResolveForwardingClosure resolve;
1116 Universe::oops_do(&resolve);
1117 SystemDictionary::oops_do(&resolve);
1118 StringTable::oops_do(&resolve);
1119 SymbolTable::oops_do(&resolve);
1120 vmSymbols::oops_do(&resolve);
1121
1122 // Set up the share data and shared code segments.
1123
1124 char* md_top = _md_vs->low();
1125 char* md_end = _md_vs->high();
1126 char* mc_top = _mc_vs->low();
1127 char* mc_end = _mc_vs->high();
1128
1129 // Reserve space for the list of klassOops whose vtables are used
1130 // for patching others as needed.
1131
1132 void** vtbl_list = (void**)md_top;
1133 int vtbl_list_size = CompactingPermGenGen::vtbl_list_size;
1134 Universe::init_self_patching_vtbl_list(vtbl_list, vtbl_list_size);
1135
1136 md_top += vtbl_list_size * sizeof(void*);
1137 void* vtable = md_top;
1138
1139 // Reserve space for a new dummy vtable for klass objects in the
1140 // heap. Generate self-patching vtable entries.
1141
1142 CompactingPermGenGen::generate_vtable_methods(vtbl_list,
1143 &vtable,
1144 &md_top, md_end,
1145 &mc_top, mc_end);
1146
1147 // Fix (forward) all of the references in these shared objects (which
1148 // are required to point ONLY to objects in the shared spaces).
1149 // Also, create a list of all objects which might later contain a
1150 // reference to a younger generation object.
1151
1152 CompactingPermGenGen* gen = (CompactingPermGenGen*)gch->perm_gen();
1153 PatchOopsClosure patch(THREAD);
1154 gen->ro_space()->object_iterate(&patch);
1155 gen->rw_space()->object_iterate(&patch);
1156
1157 // Previously method sorting was done concurrently with forwarding
1158 // pointer resolution in the shared spaces. This imposed an ordering
1159 // restriction in that methods were required to be promoted/patched
1160 // before their holder classes. (Because constant pool pointers in
1161 // methodKlasses are required to be resolved before their holder class
1162 // is visited for sorting, otherwise methods are sorted by incorrect,
1163 // pre-forwarding addresses.)
1164 //
1165 // Now, we reorder methods as a separate step after ALL forwarding
1166 // pointer resolution, so that methods can be promoted in any order
1167 // with respect to their holder classes.
1168
1169 SortMethodsClosure sort(THREAD);
1170 gen->ro_space()->object_iterate(&sort);
1171 gen->rw_space()->object_iterate(&sort);
1172 tty->print_cr("done. ");
1173 tty->cr();
1174
1175 // Reorder the system dictionary. (Moving the symbols opps affects
1176 // how the hash table indices are calculated.)
1177
1178 SystemDictionary::reorder_dictionary();
1179
1180 // Empty the non-shared heap (because most of the objects were
1181 // copied out, and the remainder cannot be considered valid oops).
1182
1183 ClearSpaceClosure csc;
1184 for (int i = 0; i < gch->n_gens(); ++i) {
1185 gch->get_gen(i)->space_iterate(&csc);
1186 }
1187 csc.do_space(gen->the_space());
1188 NOT_PRODUCT(SystemDictionary::verify();)
1189
1190 // Copy the String table, the symbol table, and the system
1191 // dictionary to the shared space in usable form. Copy the hastable
1192 // buckets first [read-write], then copy the linked lists of entries
1193 // [read-only].
1194
1195 SymbolTable::reverse(extra_symbols);
1196 NOT_PRODUCT(SymbolTable::verify());
1197 SymbolTable::copy_buckets(&md_top, md_end);
1198
1199 StringTable::reverse();
1200 NOT_PRODUCT(StringTable::verify());
1201 StringTable::copy_buckets(&md_top, md_end);
1202
1203 SystemDictionary::reverse();
1204 SystemDictionary::copy_buckets(&md_top, md_end);
1205
1206 ClassLoader::verify();
1207 ClassLoader::copy_package_info_buckets(&md_top, md_end);
1208 ClassLoader::verify();
1209
1210 SymbolTable::copy_table(&md_top, md_end);
1211 StringTable::copy_table(&md_top, md_end);
1212 SystemDictionary::copy_table(&md_top, md_end);
1213 ClassLoader::verify();
1214 ClassLoader::copy_package_info_table(&md_top, md_end);
1215 ClassLoader::verify();
1216
1217 // Print debug data.
1218
1219 if (PrintSharedSpaces) {
1220 const char* fmt = "%s space: " PTR_FORMAT " out of " PTR_FORMAT " bytes allocated at " PTR_FORMAT ".";
1221 tty->print_cr(fmt, "ro", _ro_space->used(), _ro_space->capacity(),
1222 _ro_space->bottom());
1223 tty->print_cr(fmt, "rw", _rw_space->used(), _rw_space->capacity(),
1224 _rw_space->bottom());
1225 }
1226
1227 // Write the oop data to the output array.
1228
1229 WriteClosure wc(md_top, md_end);
1230 CompactingPermGenGen::serialize_oops(&wc);
1231 md_top = wc.get_top();
1232
1233 // Update the vtable pointers in all of the Klass objects in the
1234 // heap. They should point to newly generated vtable.
1235
1236 PatchKlassVtables pkvt(vtable, _md_vs);
1237 _rw_space->object_iterate(&pkvt);
1238 pkvt.patch(vtbl_list, vtbl_list_size);
1239
1240 char* saved_vtbl = (char*)malloc(vtbl_list_size * sizeof(void*));
1241 memmove(saved_vtbl, vtbl_list, vtbl_list_size * sizeof(void*));
1242 memset(vtbl_list, 0, vtbl_list_size * sizeof(void*));
1243
1244 // Create and write the archive file that maps the shared spaces.
1245
1246 FileMapInfo* mapinfo = new FileMapInfo();
1247 mapinfo->populate_header(gch->gen_policy()->max_alignment());
1248
1249 // Pass 1 - update file offsets in header.
1250 mapinfo->write_header();
1251 mapinfo->write_space(CompactingPermGenGen::ro, _ro_space, true);
1252 _ro_space->set_saved_mark();
1253 mapinfo->write_space(CompactingPermGenGen::rw, _rw_space, false);
1254 _rw_space->set_saved_mark();
1255 mapinfo->write_region(CompactingPermGenGen::md, _md_vs->low(),
1256 pointer_delta(md_top, _md_vs->low(), sizeof(char)),
1257 SharedMiscDataSize,
1258 false, false);
1259 mapinfo->write_region(CompactingPermGenGen::mc, _mc_vs->low(),
1260 pointer_delta(mc_top, _mc_vs->low(), sizeof(char)),
1261 SharedMiscCodeSize,
1262 true, true);
1263
1264 // Pass 2 - write data.
1265 mapinfo->open_for_write();
1266 mapinfo->write_header();
1267 mapinfo->write_space(CompactingPermGenGen::ro, _ro_space, true);
1268 mapinfo->write_space(CompactingPermGenGen::rw, _rw_space, false);
1269 mapinfo->write_region(CompactingPermGenGen::md, _md_vs->low(),
1270 pointer_delta(md_top, _md_vs->low(), sizeof(char)),
1271 SharedMiscDataSize,
1272 false, false);
1273 mapinfo->write_region(CompactingPermGenGen::mc, _mc_vs->low(),
1274 pointer_delta(mc_top, _mc_vs->low(), sizeof(char)),
1275 SharedMiscCodeSize,
1276 true, true);
1277 mapinfo->close();
1278
1279 // Summarize heap.
1280 memmove(vtbl_list, saved_vtbl, vtbl_list_size * sizeof(void*));
1281 print_contents();
1282 }
1283 }; // class VM_PopulateDumpSharedSpace
1284
1285
1286 // Populate the shared spaces and dump to a file.
1287
1288 jint CompactingPermGenGen::dump_shared(GrowableArray<oop>* class_promote_order, TRAPS) {
1289 GenCollectedHeap* gch = GenCollectedHeap::heap();
1290
1291 // Calculate hash values for all of the (interned) strings to avoid
1292 // writes to shared pages in the future.
1293
1294 tty->print("Calculating hash values for String objects .. ");
1295 StringHashCodeClosure shcc(THREAD);
1296 StringTable::oops_do(&shcc);
1297 tty->print_cr("done. ");
1298
1299 CompactingPermGenGen* gen = (CompactingPermGenGen*)gch->perm_gen();
1300 VM_PopulateDumpSharedSpace op(class_promote_order,
1301 gen->ro_space(), gen->rw_space(),
1302 gen->md_space(), gen->mc_space());
1303 VMThread::execute(&op);
1304 return JNI_OK;
1305 }
1306
1307
1308 class LinkClassesClosure : public ObjectClosure {
1309 private:
1310 Thread* THREAD;
1311
1312 public:
1313 LinkClassesClosure(Thread* thread) : THREAD(thread) {}
1314
1315 void do_object(oop obj) {
1316 if (obj->is_klass()) {
1317 Klass* k = Klass::cast((klassOop) obj);
1318 if (k->oop_is_instance()) {
1319 instanceKlass* ik = (instanceKlass*) k;
1320 // Link the class to cause the bytecodes to be rewritten and the
1321 // cpcache to be created.
1322 if (ik->get_init_state() < instanceKlass::linked) {
1323 ik->link_class(THREAD);
1324 guarantee(!HAS_PENDING_EXCEPTION, "exception in class rewriting");
1325 }
1326
1327 // Create String objects from string initializer symbols.
1328 ik->constants()->resolve_string_constants(THREAD);
1329 guarantee(!HAS_PENDING_EXCEPTION, "exception resolving string constants");
1330 }
1331 }
1332 }
1333 };
1334
1335
1336 // Support for a simple checksum of the contents of the class list
1337 // file to prevent trivial tampering. The algorithm matches that in
1338 // the MakeClassList program used by the J2SE build process.
1339 #define JSUM_SEED ((jlong)CONST64(0xcafebabebabecafe))
1340 static jlong
1341 jsum(jlong start, const char *buf, const int len)
1342 {
1343 jlong h = start;
1344 char *p = (char *)buf, *e = p + len;
1345 while (p < e) {
1346 char c = *p++;
1347 if (c <= ' ') {
1348 /* Skip spaces and control characters */
1349 continue;
1350 }
1351 h = 31 * h + c;
1352 }
1353 return h;
1354 }
1355
1356
1357
1358
1359
1360 // Preload classes from a list, populate the shared spaces and dump to a
1361 // file.
1362
1363 void GenCollectedHeap::preload_and_dump(TRAPS) {
1364 TraceTime timer("Dump Shared Spaces", TraceStartupTime);
1365 ResourceMark rm;
1366
1367 // Preload classes to be shared.
1368 // Should use some hpi:: method rather than fopen() here. aB.
1369 // Construct the path to the class list (in jre/lib)
1370 // Walk up two directories from the location of the VM and
1371 // optionally tack on "lib" (depending on platform)
1372 char class_list_path[JVM_MAXPATHLEN];
1373 os::jvm_path(class_list_path, sizeof(class_list_path));
1374 for (int i = 0; i < 3; i++) {
1375 char *end = strrchr(class_list_path, *os::file_separator());
1376 if (end != NULL) *end = '\0';
1377 }
1378 int class_list_path_len = (int)strlen(class_list_path);
1379 if (class_list_path_len >= 3) {
1380 if (strcmp(class_list_path + class_list_path_len - 3, "lib") != 0) {
1381 strcat(class_list_path, os::file_separator());
1382 strcat(class_list_path, "lib");
1383 }
1384 }
1385 strcat(class_list_path, os::file_separator());
1386 strcat(class_list_path, "classlist");
1387
1388 FILE* file = fopen(class_list_path, "r");
1389 if (file != NULL) {
1390 jlong computed_jsum = JSUM_SEED;
1391 jlong file_jsum = 0;
1392
1393 char class_name[256];
1394 int class_count = 0;
1395 GenCollectedHeap* gch = GenCollectedHeap::heap();
1396 gch->_preloading_shared_classes = true;
1397 GrowableArray<oop>* class_promote_order = new GrowableArray<oop>();
1398
1399 // Preload (and intern) strings which will be used later.
1400
1401 StringTable::intern("main", THREAD);
1402 StringTable::intern("([Ljava/lang/String;)V", THREAD);
1403 StringTable::intern("Ljava/lang/Class;", THREAD);
1404
1405 StringTable::intern("I", THREAD); // Needed for StringBuffer persistence?
1406 StringTable::intern("Z", THREAD); // Needed for StringBuffer persistence?
1407
1408 // sun.io.Converters
1409 static const char obj_array_sig[] = "[[Ljava/lang/Object;";
1410 SymbolTable::lookup(obj_array_sig, (int)strlen(obj_array_sig), THREAD);
1411
1412 // java.util.HashMap
1413 static const char map_entry_array_sig[] = "[Ljava/util/Map$Entry;";
1414 SymbolTable::lookup(map_entry_array_sig, (int)strlen(map_entry_array_sig),
1415 THREAD);
1416
1417 tty->print("Loading classes to share ... ");
1418 while ((fgets(class_name, sizeof class_name, file)) != NULL) {
1419 if (*class_name == '#') {
1420 jint fsh, fsl;
1421 if (sscanf(class_name, "# %8x%8x\n", &fsh, &fsl) == 2) {
1422 file_jsum = ((jlong)(fsh) << 32) | (fsl & 0xffffffff);
1423 }
1424
1425 continue;
1426 }
1427 // Remove trailing newline
1428 size_t name_len = strlen(class_name);
1429 class_name[name_len-1] = '\0';
1430
1431 computed_jsum = jsum(computed_jsum, class_name, (const int)name_len - 1);
1432
1433 // Got a class name - load it.
1434 symbolHandle class_name_symbol = oopFactory::new_symbol(class_name,
1435 THREAD);
1436 guarantee(!HAS_PENDING_EXCEPTION, "Exception creating a symbol.");
1437 klassOop klass = SystemDictionary::resolve_or_null(class_name_symbol,
1438 THREAD);
1439 guarantee(!HAS_PENDING_EXCEPTION, "Exception resolving a class.");
1440 if (klass != NULL) {
1441 if (PrintSharedSpaces) {
1442 tty->print_cr("Shared spaces preloaded: %s", class_name);
1443 }
1444
1445
1446 instanceKlass* ik = instanceKlass::cast(klass);
1447
1448 // Should be class load order as per -XX:+TraceClassLoadingPreorder
1449 class_promote_order->append(ik->as_klassOop());
1450
1451 // Link the class to cause the bytecodes to be rewritten and the
1452 // cpcache to be created. The linking is done as soon as classes
1453 // are loaded in order that the related data structures (klass,
1454 // cpCache, Sting constants) are located together.
1455
1456 if (ik->get_init_state() < instanceKlass::linked) {
1457 ik->link_class(THREAD);
1458 guarantee(!(HAS_PENDING_EXCEPTION), "exception in class rewriting");
1459 }
1460
1461 // Create String objects from string initializer symbols.
1462
1463 ik->constants()->resolve_string_constants(THREAD);
1464
1465 class_count++;
1466 } else {
1467 if (PrintSharedSpaces) {
1468 tty->cr();
1469 tty->print_cr(" Preload failed: %s", class_name);
1470 }
1471 }
1472 file_jsum = 0; // Checksum must be on last line of file
1473 }
1474 if (computed_jsum != file_jsum) {
1475 tty->cr();
1476 tty->print_cr("Preload failed: checksum of class list was incorrect.");
1477 exit(1);
1478 }
1479
1480 tty->print_cr("done. ");
1481
1482 if (PrintSharedSpaces) {
1483 tty->print_cr("Shared spaces: preloaded %d classes", class_count);
1484 }
1485
1486 // Rewrite and unlink classes.
1487 tty->print("Rewriting and unlinking classes ... ");
1488 // Make heap parsable
1489 ensure_parsability(false); // arg is actually don't care
1490
1491 // Link any classes which got missed. (It's not quite clear why
1492 // they got missed.) This iteration would be unsafe if we weren't
1493 // single-threaded at this point; however we can't do it on the VM
1494 // thread because it requires object allocation.
1495 LinkClassesClosure lcc(Thread::current());
1496 object_iterate(&lcc);
1497 tty->print_cr("done. ");
1498
1499 // Create and dump the shared spaces.
1500 jint err = CompactingPermGenGen::dump_shared(class_promote_order, THREAD);
1501 if (err != JNI_OK) {
1502 fatal("Dumping shared spaces failed.");
1503 }
1504
1505 } else {
1506 char errmsg[JVM_MAXPATHLEN];
1507 hpi::lasterror(errmsg, JVM_MAXPATHLEN);
1508 tty->print_cr("Loading classlist failed: %s", errmsg);
1509 exit(1);
1510 }
1511
1512 // Since various initialization steps have been undone by this process,
1513 // it is not reasonable to continue running a java process.
1514 exit(0);
1515 }