1 /*
2 * Copyright (c) 2003, 2012, 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 = java_lang_String::hash_string(obj);
84 obj->int_field_put(hash_offset, hash);
85 }
86 }
87 }
88 void do_oop(narrowOop* p) { ShouldNotReachHere(); }
89 };
90
91
92 // Remove data from objects which should not appear in the shared file
93 // (as it pertains only to the current JVM).
94
95 class RemoveUnshareableInfoClosure : public ObjectClosure {
96 public:
97 void do_object(oop obj) {
98 // Zap data from the objects which is pertains only to this JVM. We
99 // want that data recreated in new JVMs when the shared file is used.
100 if (obj->is_method()) {
101 ((methodOop)obj)->remove_unshareable_info();
102 }
103 else if (obj->is_klass()) {
104 Klass::cast((klassOop)obj)->remove_unshareable_info();
105 }
106
107 // Don't save compiler related special oops (shouldn't be any yet).
108 if (obj->is_methodData() || obj->is_compiledICHolder()) {
109 ShouldNotReachHere();
110 }
111 }
112 };
113
114
115 static bool mark_object(oop obj) {
116 if (obj != NULL &&
117 !obj->is_shared() &&
118 !obj->is_forwarded() &&
119 !obj->is_gc_marked()) {
120 obj->set_mark(markOopDesc::prototype()->set_marked());
121 return true;
122 }
123
124 return false;
125 }
126
127
128 class MoveSymbols : public SymbolClosure {
129 private:
130 char* _start;
131 char* _end;
132 char* _top;
133 int _count;
134
135 bool in_shared_space(Symbol* sym) const {
136 return (char*)sym >= _start && (char*)sym < _end;
137 }
138
139 Symbol* get_shared_copy(Symbol* sym) {
140 return sym->refcount() > 0 ? NULL : (Symbol*)(_start - sym->refcount());
141 }
142
143 Symbol* make_shared_copy(Symbol* sym) {
144 Symbol* new_sym = (Symbol*)_top;
145 int size = sym->object_size();
146 _top += size * HeapWordSize;
147 if (_top <= _end) {
148 Copy::disjoint_words((HeapWord*)sym, (HeapWord*)new_sym, size);
149 // Encode a reference to the copy as a negative distance from _start
150 // When a symbol is being copied to a shared space
151 // during CDS archive creation, the original symbol is marked
152 // as relocated by putting a negative value to its _refcount field,
153 // This value is also used to find where exactly the shared copy is
154 // (see MoveSymbols::get_shared_copy), so that the other references
155 // to this symbol could be changed to point to the shared copy.
156 sym->_refcount = (int)(_start - (char*)new_sym);
157 // Mark the symbol in the shared archive as immortal so it is read only
158 // and not refcounted.
159 new_sym->_refcount = -1;
160 _count++;
161 } else {
162 report_out_of_shared_space(SharedMiscData);
163 }
164 return new_sym;
165 }
166
167 public:
168 MoveSymbols(char* top, char* end) :
169 _start(top), _end(end), _top(top), _count(0) { }
170
171 char* get_top() const { return _top; }
172 int count() const { return _count; }
173
174 void do_symbol(Symbol** p) {
175 Symbol* sym = load_symbol(p);
176 if (sym != NULL && !in_shared_space(sym)) {
177 Symbol* new_sym = get_shared_copy(sym);
178 if (new_sym == NULL) {
179 // The symbol has not been relocated yet; copy it to _top address
180 assert(sym->refcount() > 0, "should have positive reference count");
181 new_sym = make_shared_copy(sym);
182 }
183 // Make the reference point to the shared copy of the symbol
184 store_symbol(p, new_sym);
185 }
186 }
187 };
188
189
190 // Closure: mark objects closure.
191
192 class MarkObjectsOopClosure : public OopClosure {
193 public:
194 void do_oop(oop* p) { mark_object(*p); }
195 void do_oop(narrowOop* p) { ShouldNotReachHere(); }
196 };
197
198
199 class MarkObjectsSkippingKlassesOopClosure : public OopClosure {
200 public:
201 void do_oop(oop* pobj) {
202 oop obj = *pobj;
203 if (obj != NULL &&
204 !obj->is_klass()) {
205 mark_object(obj);
206 }
207 }
208 void do_oop(narrowOop* pobj) { ShouldNotReachHere(); }
209 };
210
211
212 static void mark_object_recursive_skipping_klasses(oop obj) {
213 mark_object(obj);
214 if (obj != NULL) {
215 MarkObjectsSkippingKlassesOopClosure mark_all;
216 obj->oop_iterate(&mark_all);
217 }
218 }
219
220
221 // Closure: mark common read-only objects
222
223 class MarkCommonReadOnly : public ObjectClosure {
224 private:
225 MarkObjectsOopClosure mark_all;
226 public:
227 void do_object(oop obj) {
228
229 // Mark all constMethod objects.
230
231 if (obj->is_constMethod()) {
232 mark_object(obj);
233 mark_object(constMethodOop(obj)->stackmap_data());
234 }
235
236 // Mark objects referenced by klass objects which are read-only.
237
238 else if (obj->is_klass()) {
239 Klass* k = Klass::cast((klassOop)obj);
240 mark_object(k->secondary_supers());
241
242 // The METHODS() OBJARRAYS CANNOT BE MADE READ-ONLY, even though
243 // it is never modified. Otherwise, they will be pre-marked; the
244 // GC marking phase will skip them; and by skipping them will fail
245 // to mark the methods objects referenced by the array.
246
247 if (obj->blueprint()->oop_is_instanceKlass()) {
248 instanceKlass* ik = instanceKlass::cast((klassOop)obj);
249 mark_object(ik->method_ordering());
250 mark_object(ik->local_interfaces());
251 mark_object(ik->transitive_interfaces());
252 mark_object(ik->fields());
253
254 mark_object(ik->class_annotations());
255
256 mark_object_recursive_skipping_klasses(ik->fields_annotations());
257 mark_object_recursive_skipping_klasses(ik->methods_annotations());
258 mark_object_recursive_skipping_klasses(ik->methods_parameter_annotations());
259 mark_object_recursive_skipping_klasses(ik->methods_default_annotations());
260
261 typeArrayOop inner_classes = ik->inner_classes();
262 if (inner_classes != NULL) {
263 mark_object(inner_classes);
264 }
265 }
266 }
267 }
268 };
269
270
271 // Closure: find symbol references in Java Heap objects
272
273 class CommonSymbolsClosure : public ObjectClosure {
274 private:
275 SymbolClosure* _closure;
276 public:
277 CommonSymbolsClosure(SymbolClosure* closure) : _closure(closure) { }
278
279 void do_object(oop obj) {
280
281 // Traverse symbols referenced by method objects.
282
283 if (obj->is_method()) {
284 methodOop m = methodOop(obj);
285 constantPoolOop constants = m->constants();
286 _closure->do_symbol(constants->symbol_at_addr(m->name_index()));
287 _closure->do_symbol(constants->symbol_at_addr(m->signature_index()));
288 }
289
290 // Traverse symbols referenced by klass objects which are read-only.
291
292 else if (obj->is_klass()) {
293 Klass* k = Klass::cast((klassOop)obj);
294 k->shared_symbols_iterate(_closure);
295
296 if (obj->blueprint()->oop_is_instanceKlass()) {
297 instanceKlass* ik = instanceKlass::cast((klassOop)obj);
298 instanceKlassHandle ik_h((klassOop)obj);
299 InnerClassesIterator iter(ik_h);
300 constantPoolOop constants = ik->constants();
301 for (; !iter.done(); iter.next()) {
302 int index = iter.inner_name_index();
303
304 if (index != 0) {
305 _closure->do_symbol(constants->symbol_at_addr(index));
306 }
307 }
308 }
309 }
310
311 // Traverse symbols referenced by other constantpool entries.
312
313 else if (obj->is_constantPool()) {
314 constantPoolOop(obj)->shared_symbols_iterate(_closure);
315 }
316 }
317 };
318
319
320 // Closure: mark char arrays used by strings
321
322 class MarkStringValues : public ObjectClosure {
323 private:
324 MarkObjectsOopClosure mark_all;
325 public:
326 void do_object(oop obj) {
327
328 // Character arrays referenced by String objects are read-only.
329
330 if (java_lang_String::is_instance(obj)) {
331 mark_object(java_lang_String::value(obj));
332 }
333 }
334 };
335
336
337 #ifdef DEBUG
338 // Closure: Check for objects left in the heap which have not been moved.
339
340 class CheckRemainingObjects : public ObjectClosure {
341 private:
342 int count;
343
344 public:
345 CheckRemainingObjects() {
346 count = 0;
347 }
348
349 void do_object(oop obj) {
350 if (!obj->is_shared() &&
351 !obj->is_forwarded()) {
352 ++count;
353 if (Verbose) {
354 tty->print("Unreferenced object: ");
355 obj->print_on(tty);
356 }
357 }
358 }
359
360 void status() {
361 tty->print_cr("%d objects no longer referenced, not shared.", count);
362 }
363 };
364 #endif
365
366
367 // Closure: Mark remaining objects read-write, except Strings.
368
369 class MarkReadWriteObjects : public ObjectClosure {
370 private:
371 MarkObjectsOopClosure mark_objects;
372 public:
373 void do_object(oop obj) {
374
375 // The METHODS() OBJARRAYS CANNOT BE MADE READ-ONLY, even though
376 // it is never modified. Otherwise, they will be pre-marked; the
377 // GC marking phase will skip them; and by skipping them will fail
378 // to mark the methods objects referenced by the array.
379
380 if (obj->is_klass()) {
381 mark_object(obj);
382 Klass* k = klassOop(obj)->klass_part();
383 mark_object(k->java_mirror());
384 if (obj->blueprint()->oop_is_instanceKlass()) {
385 instanceKlass* ik = (instanceKlass*)k;
386 mark_object(ik->methods());
387 mark_object(ik->constants());
388 }
389 if (obj->blueprint()->oop_is_javaArray()) {
390 arrayKlass* ak = (arrayKlass*)k;
391 mark_object(ak->component_mirror());
392 }
393 return;
394 }
395
396 // Mark constantPool tags and the constantPoolCache.
397
398 else if (obj->is_constantPool()) {
399 constantPoolOop pool = constantPoolOop(obj);
400 mark_object(pool->cache());
401 pool->shared_tags_iterate(&mark_objects);
402 return;
403 }
404
405 // Mark all method objects.
406
407 if (obj->is_method()) {
408 mark_object(obj);
409 }
410 }
411 };
412
413
414 // Closure: Mark String objects read-write.
415
416 class MarkStringObjects : public ObjectClosure {
417 private:
418 MarkObjectsOopClosure mark_objects;
419 public:
420 void do_object(oop obj) {
421
422 // Mark String objects referenced by constant pool entries.
423
424 if (obj->is_constantPool()) {
425 constantPoolOop pool = constantPoolOop(obj);
426 pool->shared_strings_iterate(&mark_objects);
427 return;
428 }
429 }
430 };
431
432
433 // Move objects matching specified type (ie. lock_bits) to the specified
434 // space.
435
436 class MoveMarkedObjects : public ObjectClosure {
437 private:
438 OffsetTableContigSpace* _space;
439 bool _read_only;
440
441 public:
442 MoveMarkedObjects(OffsetTableContigSpace* space, bool read_only) {
443 _space = space;
444 _read_only = read_only;
445 }
446
447 void do_object(oop obj) {
448 if (obj->is_shared()) {
449 return;
450 }
451 if (obj->is_gc_marked() && obj->forwardee() == NULL) {
452 int s = obj->size();
453 oop sh_obj = (oop)_space->allocate(s);
454 if (sh_obj == NULL) {
455 report_out_of_shared_space(_read_only ? SharedReadOnly : SharedReadWrite);
456 }
457 if (PrintSharedSpaces && Verbose && WizardMode) {
458 tty->print_cr("\nMoveMarkedObjects: " PTR_FORMAT " -> " PTR_FORMAT " %s", obj, sh_obj,
459 (_read_only ? "ro" : "rw"));
460 }
461 Copy::aligned_disjoint_words((HeapWord*)obj, (HeapWord*)sh_obj, s);
462 obj->forward_to(sh_obj);
463 if (_read_only) {
464 // Readonly objects: set hash value to self pointer and make gc_marked.
465 sh_obj->forward_to(sh_obj);
466 } else {
467 sh_obj->init_mark();
468 }
469 }
470 }
471 };
472
473 static void mark_and_move(oop obj, MoveMarkedObjects* move) {
474 if (mark_object(obj)) move->do_object(obj);
475 }
476
477 enum order_policy {
478 OP_favor_startup = 0,
479 OP_balanced = 1,
480 OP_favor_runtime = 2
481 };
482
483 static void mark_and_move_for_policy(order_policy policy, oop obj, MoveMarkedObjects* move) {
484 if (SharedOptimizeColdStartPolicy >= policy) mark_and_move(obj, move);
485 }
486
487 class MarkAndMoveOrderedReadOnly : public ObjectClosure {
488 private:
489 MoveMarkedObjects *_move_ro;
490
491 public:
492 MarkAndMoveOrderedReadOnly(MoveMarkedObjects *move_ro) : _move_ro(move_ro) {}
493
494 void do_object(oop obj) {
495 if (obj->is_klass() && obj->blueprint()->oop_is_instanceKlass()) {
496 instanceKlass* ik = instanceKlass::cast((klassOop)obj);
497 int i;
498
499 if (ik->super() != NULL) {
500 do_object(ik->super());
501 }
502
503 objArrayOop interfaces = ik->local_interfaces();
504 mark_and_move_for_policy(OP_favor_startup, interfaces, _move_ro);
505 for(i = 0; i < interfaces->length(); i++) {
506 klassOop k = klassOop(interfaces->obj_at(i));
507 do_object(k);
508 }
509
510 objArrayOop methods = ik->methods();
511 for(i = 0; i < methods->length(); i++) {
512 methodOop m = methodOop(methods->obj_at(i));
513 mark_and_move_for_policy(OP_favor_startup, m->constMethod(), _move_ro);
514 mark_and_move_for_policy(OP_favor_runtime, m->constMethod()->stackmap_data(), _move_ro);
515 }
516
517 mark_and_move_for_policy(OP_favor_startup, ik->transitive_interfaces(), _move_ro);
518 mark_and_move_for_policy(OP_favor_startup, ik->fields(), _move_ro);
519
520 mark_and_move_for_policy(OP_favor_runtime, ik->secondary_supers(), _move_ro);
521 mark_and_move_for_policy(OP_favor_runtime, ik->method_ordering(), _move_ro);
522 mark_and_move_for_policy(OP_favor_runtime, ik->class_annotations(), _move_ro);
523 mark_and_move_for_policy(OP_favor_runtime, ik->fields_annotations(), _move_ro);
524 mark_and_move_for_policy(OP_favor_runtime, ik->methods_annotations(), _move_ro);
525 mark_and_move_for_policy(OP_favor_runtime, ik->methods_parameter_annotations(), _move_ro);
526 mark_and_move_for_policy(OP_favor_runtime, ik->methods_default_annotations(), _move_ro);
527 mark_and_move_for_policy(OP_favor_runtime, ik->inner_classes(), _move_ro);
528 mark_and_move_for_policy(OP_favor_runtime, ik->secondary_supers(), _move_ro);
529 }
530 }
531 };
532
533 class MarkAndMoveOrderedReadWrite: public ObjectClosure {
534 private:
535 MoveMarkedObjects *_move_rw;
536
537 public:
538 MarkAndMoveOrderedReadWrite(MoveMarkedObjects *move_rw) : _move_rw(move_rw) {}
539
540 void do_object(oop obj) {
541 if (obj->is_klass() && obj->blueprint()->oop_is_instanceKlass()) {
542 instanceKlass* ik = instanceKlass::cast((klassOop)obj);
543 int i;
544
545 mark_and_move_for_policy(OP_favor_startup, ik->as_klassOop(), _move_rw);
546
547 if (ik->super() != NULL) {
548 do_object(ik->super());
549 }
550
551 objArrayOop interfaces = ik->local_interfaces();
552 for(i = 0; i < interfaces->length(); i++) {
553 klassOop k = klassOop(interfaces->obj_at(i));
554 mark_and_move_for_policy(OP_favor_startup, k, _move_rw);
555 do_object(k);
556 }
557
558 objArrayOop methods = ik->methods();
559 mark_and_move_for_policy(OP_favor_startup, methods, _move_rw);
560 for(i = 0; i < methods->length(); i++) {
561 methodOop m = methodOop(methods->obj_at(i));
562 mark_and_move_for_policy(OP_favor_startup, m, _move_rw);
563 mark_and_move_for_policy(OP_favor_startup, ik->constants(), _move_rw); // idempotent
564 mark_and_move_for_policy(OP_balanced, ik->constants()->cache(), _move_rw); // idempotent
565 mark_and_move_for_policy(OP_balanced, ik->constants()->tags(), _move_rw); // idempotent
566 }
567
568 mark_and_move_for_policy(OP_favor_startup, ik->as_klassOop()->klass(), _move_rw);
569 mark_and_move_for_policy(OP_favor_startup, ik->constants()->klass(), _move_rw);
570
571 // Although Java mirrors are marked in MarkReadWriteObjects,
572 // apparently they were never moved into shared spaces since
573 // MoveMarkedObjects skips marked instance oops. This may
574 // be a bug in the original implementation or simply the vestige
575 // of an abandoned experiment. Nevertheless we leave a hint
576 // here in case this capability is ever correctly implemented.
577 //
578 // mark_and_move_for_policy(OP_favor_runtime, ik->java_mirror(), _move_rw);
579 }
580 }
581
582 };
583
584 // Adjust references in oops to refer to shared spaces.
585
586 class ResolveForwardingClosure: public OopClosure {
587 public:
588 void do_oop(oop* p) {
589 oop obj = *p;
590 if (!obj->is_shared()) {
591 if (obj != NULL) {
592 oop f = obj->forwardee();
593 guarantee(f->is_shared(), "Oop doesn't refer to shared space.");
594 *p = f;
595 }
596 }
597 }
598 void do_oop(narrowOop* pobj) { ShouldNotReachHere(); }
599 };
600
601
602 // The methods array must be reordered by Symbol* address.
603 // (See classFileParser.cpp where methods in a class are originally
604 // sorted). The addresses of symbols have been changed as a result
605 // of moving to the shared space.
606
607 class SortMethodsClosure: public ObjectClosure {
608 public:
609 void do_object(oop obj) {
610 if (obj->blueprint()->oop_is_instanceKlass()) {
611 instanceKlass* ik = instanceKlass::cast((klassOop)obj);
612 methodOopDesc::sort_methods(ik->methods(),
613 ik->methods_annotations(),
614 ik->methods_parameter_annotations(),
615 ik->methods_default_annotations(),
616 true /* idempotent, slow */);
617 }
618 }
619 };
620
621 // Vtable and Itable indices are calculated based on methods array
622 // order (see klassItable::compute_itable_index()). Must reinitialize
623 // after ALL methods of ALL classes have been reordered.
624 // We assume that since checkconstraints is false, this method
625 // cannot throw an exception. An exception here would be
626 // problematic since this is the VMThread, not a JavaThread.
627
628 class ReinitializeTables: public ObjectClosure {
629 private:
630 Thread* _thread;
631
632 public:
633 ReinitializeTables(Thread* thread) : _thread(thread) {}
634
635 // Initialize super vtable first, check if already initialized to avoid
636 // quadradic behavior. The vtable is cleared in remove_unshareable_info.
637 void reinitialize_vtables(klassOop k) {
638 if (k->blueprint()->oop_is_instanceKlass()) {
639 instanceKlass* ik = instanceKlass::cast(k);
640 if (ik->vtable()->is_initialized()) return;
641 if (ik->super() != NULL) {
642 reinitialize_vtables(ik->super());
643 }
644 ik->vtable()->initialize_vtable(false, _thread);
645 }
646 }
647
648 void do_object(oop obj) {
649 if (obj->blueprint()->oop_is_instanceKlass()) {
650 instanceKlass* ik = instanceKlass::cast((klassOop)obj);
651 ResourceMark rm(_thread);
652 ik->itable()->initialize_itable(false, _thread);
653 reinitialize_vtables((klassOop)obj);
654 #ifdef ASSERT
655 ik->vtable()->verify(tty, true);
656 #endif // ASSERT
657 } else if (obj->blueprint()->oop_is_arrayKlass()) {
658 // The vtable for array klasses are that of its super class,
659 // ie. java.lang.Object.
660 arrayKlass* ak = arrayKlass::cast((klassOop)obj);
661 if (ak->vtable()->is_initialized()) return;
662 ak->vtable()->initialize_vtable(false, _thread);
663 }
664 }
665 };
666
667
668 // Adjust references in oops to refer to shared spaces.
669
670 class PatchOopsClosure: public ObjectClosure {
671 private:
672 Thread* _thread;
673 ResolveForwardingClosure resolve;
674
675 public:
676 PatchOopsClosure(Thread* thread) : _thread(thread) {}
677
678 void do_object(oop obj) {
679 obj->oop_iterate_header(&resolve);
680 obj->oop_iterate(&resolve);
681
682 assert(obj->klass()->is_shared(), "Klass not pointing into shared space.");
683
684 // If the object is a Java object or class which might (in the
685 // future) contain a reference to a young gen object, add it to the
686 // list.
687
688 if (obj->is_klass() || obj->is_instance()) {
689 if (obj->is_klass() ||
690 obj->is_a(SystemDictionary::Class_klass()) ||
691 obj->is_a(SystemDictionary::Throwable_klass())) {
692 // Do nothing
693 }
694 else if (obj->is_a(SystemDictionary::String_klass())) {
695 // immutable objects.
696 } else {
697 // someone added an object we hadn't accounted for.
698 ShouldNotReachHere();
699 }
700 }
701 }
702 };
703
704
705 // Empty the young and old generations.
706
707 class ClearSpaceClosure : public SpaceClosure {
708 public:
709 void do_space(Space* s) {
710 s->clear(SpaceDecorator::Mangle);
711 }
712 };
713
714
715 // Closure for serializing initialization data out to a data area to be
716 // written to the shared file.
717
718 class WriteClosure : public SerializeOopClosure {
719 private:
720 oop* top;
721 char* end;
722
723 inline void check_space() {
724 if ((char*)top + sizeof(oop) > end) {
725 report_out_of_shared_space(SharedMiscData);
726 }
727 }
728
729
730 public:
731 WriteClosure(char* md_top, char* md_end) {
732 top = (oop*)md_top;
733 end = md_end;
734 }
735
736 char* get_top() { return (char*)top; }
737
738 void do_oop(oop* p) {
739 check_space();
740 oop obj = *p;
741 assert(obj->is_oop_or_null(), "invalid oop");
742 assert(obj == NULL || obj->is_shared(),
743 "Oop in shared space not pointing into shared space.");
744 *top = obj;
745 ++top;
746 }
747
748 void do_oop(narrowOop* pobj) { ShouldNotReachHere(); }
749
750 void do_int(int* p) {
751 check_space();
752 *top = (oop)(intptr_t)*p;
753 ++top;
754 }
755
756 void do_size_t(size_t* p) {
757 check_space();
758 *top = (oop)(intptr_t)*p;
759 ++top;
760 }
761
762 void do_ptr(void** p) {
763 check_space();
764 *top = (oop)*p;
765 ++top;
766 }
767
768 void do_ptr(HeapWord** p) { do_ptr((void **) p); }
769
770 void do_tag(int tag) {
771 check_space();
772 *top = (oop)(intptr_t)tag;
773 ++top;
774 }
775
776 void do_region(u_char* start, size_t size) {
777 if ((char*)top + size > end) {
778 report_out_of_shared_space(SharedMiscData);
779 }
780 assert((intptr_t)start % sizeof(oop) == 0, "bad alignment");
781 assert(size % sizeof(oop) == 0, "bad size");
782 do_tag((int)size);
783 while (size > 0) {
784 *top = *(oop*)start;
785 ++top;
786 start += sizeof(oop);
787 size -= sizeof(oop);
788 }
789 }
790
791 bool reading() const { return false; }
792 };
793
794
795 class ResolveConstantPoolsClosure : public ObjectClosure {
796 private:
797 TRAPS;
798 public:
799 ResolveConstantPoolsClosure(Thread *t) {
800 __the_thread__ = t;
801 }
802 void do_object(oop obj) {
803 if (obj->is_constantPool()) {
804 constantPoolOop cpool = (constantPoolOop)obj;
805 int unresolved = cpool->pre_resolve_shared_klasses(THREAD);
806 }
807 }
808 };
809
810
811 // Print a summary of the contents of the read/write spaces to help
812 // identify objects which might be able to be made read-only. At this
813 // point, the objects have been written, and we can trash them as
814 // needed.
815
816 static void print_contents() {
817 if (PrintSharedSpaces) {
818 GenCollectedHeap* gch = GenCollectedHeap::heap();
819 CompactingPermGenGen* gen = (CompactingPermGenGen*)gch->perm_gen();
820
821 // High level summary of the read-only space:
822
823 ClassifyObjectClosure coc;
824 tty->cr(); tty->print_cr("ReadOnly space:");
825 gen->ro_space()->object_iterate(&coc);
826 coc.print();
827
828 // High level summary of the read-write space:
829
830 coc.reset();
831 tty->cr(); tty->print_cr("ReadWrite space:");
832 gen->rw_space()->object_iterate(&coc);
833 coc.print();
834
835 // Reset counters
836
837 ClearAllocCountClosure cacc;
838 gen->ro_space()->object_iterate(&cacc);
839 gen->rw_space()->object_iterate(&cacc);
840 coc.reset();
841
842 // Lower level summary of the read-only space:
843
844 gen->ro_space()->object_iterate(&coc);
845 tty->cr(); tty->print_cr("ReadOnly space:");
846 ClassifyInstanceKlassClosure cikc;
847 gen->rw_space()->object_iterate(&cikc);
848 cikc.print();
849
850 // Reset counters
851
852 gen->ro_space()->object_iterate(&cacc);
853 gen->rw_space()->object_iterate(&cacc);
854 coc.reset();
855
856 // Lower level summary of the read-write space:
857
858 gen->rw_space()->object_iterate(&coc);
859 cikc.reset();
860 tty->cr(); tty->print_cr("ReadWrite space:");
861 gen->rw_space()->object_iterate(&cikc);
862 cikc.print();
863 }
864 }
865
866
867 // Patch C++ vtable pointer in klass oops.
868
869 // Klass objects contain references to c++ vtables in the JVM library.
870 // Fix them to point to our constructed vtables. However, don't iterate
871 // across the space while doing this, as that causes the vtables to be
872 // patched, undoing our useful work. Instead, iterate to make a list,
873 // then use the list to do the fixing.
874 //
875 // Our constructed vtables:
876 // Dump time:
877 // 1. init_self_patching_vtbl_list: table of pointers to current virtual method addrs
878 // 2. generate_vtable_methods: create jump table, appended to above vtbl_list
879 // 3. PatchKlassVtables: for Klass list, patch the vtable entry to point to jump table
880 // rather than to current vtbl
881 // Table layout: NOTE FIXED SIZE
882 // 1. vtbl pointers
883 // 2. #Klass X #virtual methods per Klass
884 // 1 entry for each, in the order:
885 // Klass1:method1 entry, Klass1:method2 entry, ... Klass1:method<num_virtuals> entry
886 // Klass2:method1 entry, Klass2:method2 entry, ... Klass2:method<num_virtuals> entry
887 // ...
888 // Klass<vtbl_list_size>:method1 entry, Klass<vtbl_list_size>:method2 entry,
889 // ... Klass<vtbl_list_size>:method<num_virtuals> entry
890 // Sample entry: (Sparc):
891 // save(sp, -256, sp)
892 // ba,pt common_code
893 // mov XXX, %L0 %L0 gets: Klass index <<8 + method index (note: max method index 255)
894 //
895 // Restore time:
896 // 1. initialize_oops: reserve space for table
897 // 2. init_self_patching_vtbl_list: update pointers to NEW virtual method addrs in text
898 //
899 // Execution time:
900 // First virtual method call for any object of these Klass types:
901 // 1. object->klass->klass_part
902 // 2. vtable entry for that klass_part points to the jump table entries
903 // 3. branches to common_code with %O0/klass_part, %L0: Klass index <<8 + method index
904 // 4. common_code:
905 // Get address of new vtbl pointer for this Klass from updated table
906 // Update new vtbl pointer in the Klass: future virtual calls go direct
907 // Jump to method, using new vtbl pointer and method index
908
909 class PatchKlassVtables: public ObjectClosure {
910 private:
911 GrowableArray<klassOop>* _klass_objects;
912
913 public:
914 PatchKlassVtables() {
915 _klass_objects = new GrowableArray<klassOop>();
916 }
917
918 void do_object(oop obj) {
919 if (obj->is_klass()) {
920 _klass_objects->append(klassOop(obj));
921 }
922 }
923
924 void patch(void** vtbl_list, void* new_vtable_start) {
925 int n = _klass_objects->length();
926 for (int i = 0; i < n; i++) {
927 klassOop obj = (klassOop)_klass_objects->at(i);
928 Klass* k = obj->klass_part();
929 *(void**)k = CompactingPermGenGen::find_matching_vtbl_ptr(
930 vtbl_list, new_vtable_start, k);
931 }
932 }
933 };
934
935 // Walk through all symbols and patch their vtable pointers.
936 // Note that symbols have vtable pointers only in non-product builds
937 // (see allocation.hpp).
938
939 #ifndef PRODUCT
940 class PatchSymbolVtables: public SymbolClosure {
941 private:
942 void* _new_vtbl_ptr;
943
944 public:
945 PatchSymbolVtables(void** vtbl_list, void* new_vtable_start) {
946 Symbol s;
947 _new_vtbl_ptr = CompactingPermGenGen::find_matching_vtbl_ptr(
948 vtbl_list, new_vtable_start, &s);
949 }
950
951 void do_symbol(Symbol** p) {
952 Symbol* sym = load_symbol(p);
953 *(void**)sym = _new_vtbl_ptr;
954 }
955 };
956 #endif
957
958
959 // Populate the shared space.
960
961 class VM_PopulateDumpSharedSpace: public VM_Operation {
962 private:
963 GrowableArray<oop> *_class_promote_order;
964 OffsetTableContigSpace* _ro_space;
965 OffsetTableContigSpace* _rw_space;
966 VirtualSpace* _md_vs;
967 VirtualSpace* _mc_vs;
968
969 public:
970 VM_PopulateDumpSharedSpace(GrowableArray<oop> *class_promote_order,
971 OffsetTableContigSpace* ro_space,
972 OffsetTableContigSpace* rw_space,
973 VirtualSpace* md_vs, VirtualSpace* mc_vs) {
974 _class_promote_order = class_promote_order;
975 _ro_space = ro_space;
976 _rw_space = rw_space;
977 _md_vs = md_vs;
978 _mc_vs = mc_vs;
979 }
980
981 VMOp_Type type() const { return VMOp_PopulateDumpSharedSpace; }
982 void doit() {
983 Thread* THREAD = VMThread::vm_thread();
984 NOT_PRODUCT(SystemDictionary::verify();)
985 // The following guarantee is meant to ensure that no loader constraints
986 // exist yet, since the constraints table is not shared. This becomes
987 // more important now that we don't re-initialize vtables/itables for
988 // shared classes at runtime, where constraints were previously created.
989 guarantee(SystemDictionary::constraints()->number_of_entries() == 0,
990 "loader constraints are not saved");
991 // Revisit and implement this if we prelink method handle call sites:
992 guarantee(SystemDictionary::invoke_method_table() == NULL ||
993 SystemDictionary::invoke_method_table()->number_of_entries() == 0,
994 "invoke method table is not saved");
995 GenCollectedHeap* gch = GenCollectedHeap::heap();
996
997 // At this point, many classes have been loaded.
998
999 // Update all the fingerprints in the shared methods.
1000
1001 tty->print("Calculating fingerprints ... ");
1002 FingerprintMethodsClosure fpmc;
1003 gch->object_iterate(&fpmc);
1004 tty->print_cr("done. ");
1005
1006 // Remove all references outside the heap.
1007
1008 tty->print("Removing unshareable information ... ");
1009 RemoveUnshareableInfoClosure ruic;
1010 gch->object_iterate(&ruic);
1011 tty->print_cr("done. ");
1012
1013 // Move the objects in three passes.
1014
1015 MarkObjectsOopClosure mark_all;
1016 MarkCommonReadOnly mark_common_ro;
1017 MarkStringValues mark_string_values;
1018 MarkReadWriteObjects mark_rw;
1019 MarkStringObjects mark_strings;
1020 MoveMarkedObjects move_ro(_ro_space, true);
1021 MoveMarkedObjects move_rw(_rw_space, false);
1022
1023 // The SharedOptimizeColdStart VM option governs the new layout
1024 // algorithm for promoting classes into the shared archive.
1025 // The general idea is to minimize cold start time by laying
1026 // out the objects in the order they are accessed at startup time.
1027 // By doing this we are trying to eliminate out-of-order accesses
1028 // in the shared archive. This benefits cold startup time by making
1029 // disk reads as sequential as possible during class loading and
1030 // bootstrapping activities. There may also be a small secondary
1031 // effect of better "packing" of more commonly used data on a smaller
1032 // number of pages, although no direct benefit has been measured from
1033 // this effect.
1034 //
1035 // At the class level of granularity, the promotion order is dictated
1036 // by the classlist file whose generation is discussed elsewhere.
1037 //
1038 // At smaller granularity, optimal ordering was determined by an
1039 // offline analysis of object access order in the shared archive.
1040 // The dbx watchpoint facility, combined with SA post-processing,
1041 // was used to observe common access patterns primarily during
1042 // classloading. This information was used to craft the promotion
1043 // order seen in the following closures.
1044 //
1045 // The observed access order is mostly governed by what happens
1046 // in SystemDictionary::load_shared_class(). NOTE WELL - care
1047 // should be taken when making changes to this method, because it
1048 // may invalidate assumptions made about access order!
1049 //
1050 // (Ideally, there would be a better way to manage changes to
1051 // the access order. Unfortunately a generic in-VM solution for
1052 // dynamically observing access order and optimizing shared
1053 // archive layout is pretty difficult. We go with the static
1054 // analysis because the code is fairly mature at this point
1055 // and we're betting that the access order won't change much.)
1056
1057 MarkAndMoveOrderedReadOnly mark_and_move_ordered_ro(&move_ro);
1058 MarkAndMoveOrderedReadWrite mark_and_move_ordered_rw(&move_rw);
1059
1060 // Set up the share data and shared code segments.
1061
1062 char* md_top = _md_vs->low();
1063 char* md_end = _md_vs->high();
1064 char* mc_top = _mc_vs->low();
1065 char* mc_end = _mc_vs->high();
1066
1067 // Reserve space for the list of klassOops whose vtables are used
1068 // for patching others as needed.
1069
1070 void** vtbl_list = (void**)md_top;
1071 int vtbl_list_size = CompactingPermGenGen::vtbl_list_size;
1072 Universe::init_self_patching_vtbl_list(vtbl_list, vtbl_list_size);
1073
1074 md_top += vtbl_list_size * sizeof(void*);
1075 void* vtable = md_top;
1076
1077 // Reserve space for a new dummy vtable for klass objects in the
1078 // heap. Generate self-patching vtable entries.
1079
1080 CompactingPermGenGen::generate_vtable_methods(vtbl_list,
1081 &vtable,
1082 &md_top, md_end,
1083 &mc_top, mc_end);
1084
1085 // Reserve space for the total size and the number of stored symbols.
1086
1087 md_top += sizeof(intptr_t) * 2;
1088
1089 MoveSymbols move_symbols(md_top, md_end);
1090 CommonSymbolsClosure traverse_common_symbols(&move_symbols);
1091
1092 // Phase 1a: remove symbols with _refcount == 0
1093
1094 SymbolTable::unlink();
1095
1096 // Phase 1b: move commonly used symbols referenced by oop fields.
1097
1098 tty->print("Moving common symbols to metadata section at " PTR_FORMAT " ... ",
1099 move_symbols.get_top());
1100 gch->object_iterate(&traverse_common_symbols);
1101 tty->print_cr("done. ");
1102
1103 // Phase 1c: move known names and signatures.
1104
1105 tty->print("Moving vmSymbols to metadata section at " PTR_FORMAT " ... ",
1106 move_symbols.get_top());
1107 vmSymbols::symbols_do(&move_symbols);
1108 tty->print_cr("done. ");
1109
1110 // Phase 1d: move the remaining symbols by scanning the whole SymbolTable.
1111
1112 void* extra_symbols = move_symbols.get_top();
1113 tty->print("Moving the remaining symbols to metadata section at " PTR_FORMAT " ... ",
1114 move_symbols.get_top());
1115 SymbolTable::symbols_do(&move_symbols);
1116 tty->print_cr("done. ");
1117
1118 // Record the total length of all symbols at the beginning of the block.
1119 ((intptr_t*)md_top)[-2] = move_symbols.get_top() - md_top;
1120 ((intptr_t*)md_top)[-1] = move_symbols.count();
1121 tty->print_cr("Moved %d symbols, %d bytes.",
1122 move_symbols.count(), move_symbols.get_top() - md_top);
1123 // Advance the pointer to the end of symbol store.
1124 md_top = move_symbols.get_top();
1125
1126
1127 // Phase 2: move commonly used read-only objects to the read-only space.
1128
1129 if (SharedOptimizeColdStart) {
1130 tty->print("Moving pre-ordered read-only objects to shared space at " PTR_FORMAT " ... ",
1131 _ro_space->top());
1132 for (int i = 0; i < _class_promote_order->length(); i++) {
1133 oop obj = _class_promote_order->at(i);
1134 mark_and_move_ordered_ro.do_object(obj);
1135 }
1136 tty->print_cr("done. ");
1137 }
1138
1139 tty->print("Moving read-only objects to shared space at " PTR_FORMAT " ... ",
1140 _ro_space->top());
1141 gch->object_iterate(&mark_common_ro);
1142 gch->object_iterate(&move_ro);
1143 tty->print_cr("done. ");
1144
1145 // Phase 3: move String character arrays to the read-only space.
1146
1147 tty->print("Moving string char arrays to shared space at " PTR_FORMAT " ... ",
1148 _ro_space->top());
1149 gch->object_iterate(&mark_string_values);
1150 gch->object_iterate(&move_ro);
1151 tty->print_cr("done. ");
1152
1153 // Phase 4: move read-write objects to the read-write space, except
1154 // Strings.
1155
1156 if (SharedOptimizeColdStart) {
1157 tty->print("Moving pre-ordered read-write objects to shared space at " PTR_FORMAT " ... ",
1158 _rw_space->top());
1159 for (int i = 0; i < _class_promote_order->length(); i++) {
1160 oop obj = _class_promote_order->at(i);
1161 mark_and_move_ordered_rw.do_object(obj);
1162 }
1163 tty->print_cr("done. ");
1164 }
1165 tty->print("Moving read-write objects to shared space at " PTR_FORMAT " ... ",
1166 _rw_space->top());
1167 Universe::oops_do(&mark_all, true);
1168 SystemDictionary::oops_do(&mark_all);
1169 oop tmp = Universe::arithmetic_exception_instance();
1170 mark_object(java_lang_Throwable::message(tmp));
1171 gch->object_iterate(&mark_rw);
1172 gch->object_iterate(&move_rw);
1173 tty->print_cr("done. ");
1174
1175 // Phase 5: move String objects to the read-write space.
1176
1177 tty->print("Moving String objects to shared space at " PTR_FORMAT " ... ",
1178 _rw_space->top());
1179 StringTable::oops_do(&mark_all);
1180 gch->object_iterate(&mark_strings);
1181 gch->object_iterate(&move_rw);
1182 tty->print_cr("done. ");
1183 tty->print_cr("Read-write space ends at " PTR_FORMAT ", %d bytes.",
1184 _rw_space->top(), _rw_space->used());
1185
1186 #ifdef DEBUG
1187 // Check: scan for objects which were not moved.
1188
1189 CheckRemainingObjects check_objects;
1190 gch->object_iterate(&check_objects);
1191 check_objects.status();
1192 #endif
1193
1194 // Resolve forwarding in objects and saved C++ structures
1195 tty->print("Updating references to shared objects ... ");
1196 ResolveForwardingClosure resolve;
1197 Universe::oops_do(&resolve);
1198 SystemDictionary::oops_do(&resolve);
1199 StringTable::oops_do(&resolve);
1200
1201 // Fix (forward) all of the references in these shared objects (which
1202 // are required to point ONLY to objects in the shared spaces).
1203 // Also, create a list of all objects which might later contain a
1204 // reference to a younger generation object.
1205
1206 CompactingPermGenGen* gen = (CompactingPermGenGen*)gch->perm_gen();
1207 PatchOopsClosure patch(THREAD);
1208 gen->ro_space()->object_iterate(&patch);
1209 gen->rw_space()->object_iterate(&patch);
1210
1211 // Previously method sorting was done concurrently with forwarding
1212 // pointer resolution in the shared spaces. This imposed an ordering
1213 // restriction in that methods were required to be promoted/patched
1214 // before their holder classes. (Because constant pool pointers in
1215 // methodKlasses are required to be resolved before their holder class
1216 // is visited for sorting, otherwise methods are sorted by incorrect,
1217 // pre-forwarding addresses.)
1218 //
1219 // Now, we reorder methods as a separate step after ALL forwarding
1220 // pointer resolution, so that methods can be promoted in any order
1221 // with respect to their holder classes.
1222
1223 SortMethodsClosure sort;
1224 gen->ro_space()->object_iterate(&sort);
1225 gen->rw_space()->object_iterate(&sort);
1226
1227 ReinitializeTables reinit_tables(THREAD);
1228 gen->ro_space()->object_iterate(&reinit_tables);
1229 gen->rw_space()->object_iterate(&reinit_tables);
1230 tty->print_cr("done. ");
1231 tty->cr();
1232
1233 // Reorder the system dictionary. (Moving the symbols opps affects
1234 // how the hash table indices are calculated.)
1235
1236 SystemDictionary::reorder_dictionary();
1237
1238 // Empty the non-shared heap (because most of the objects were
1239 // copied out, and the remainder cannot be considered valid oops).
1240
1241 ClearSpaceClosure csc;
1242 for (int i = 0; i < gch->n_gens(); ++i) {
1243 gch->get_gen(i)->space_iterate(&csc);
1244 }
1245 csc.do_space(gen->the_space());
1246 NOT_PRODUCT(SystemDictionary::verify();)
1247
1248 // Copy the String table, the symbol table, and the system
1249 // dictionary to the shared space in usable form. Copy the hastable
1250 // buckets first [read-write], then copy the linked lists of entries
1251 // [read-only].
1252
1253 SymbolTable::reverse(extra_symbols);
1254 NOT_PRODUCT(SymbolTable::verify());
1255 SymbolTable::copy_buckets(&md_top, md_end);
1256
1257 StringTable::reverse();
1258 NOT_PRODUCT(StringTable::verify());
1259 StringTable::copy_buckets(&md_top, md_end);
1260
1261 SystemDictionary::reverse();
1262 SystemDictionary::copy_buckets(&md_top, md_end);
1263
1264 ClassLoader::verify();
1265 ClassLoader::copy_package_info_buckets(&md_top, md_end);
1266 ClassLoader::verify();
1267
1268 SymbolTable::copy_table(&md_top, md_end);
1269 StringTable::copy_table(&md_top, md_end);
1270 SystemDictionary::copy_table(&md_top, md_end);
1271 ClassLoader::verify();
1272 ClassLoader::copy_package_info_table(&md_top, md_end);
1273 ClassLoader::verify();
1274
1275 // Print debug data.
1276
1277 if (PrintSharedSpaces) {
1278 const char* fmt = "%s space: " PTR_FORMAT " out of " PTR_FORMAT " bytes allocated at " PTR_FORMAT ".";
1279 tty->print_cr(fmt, "ro", _ro_space->used(), _ro_space->capacity(),
1280 _ro_space->bottom());
1281 tty->print_cr(fmt, "rw", _rw_space->used(), _rw_space->capacity(),
1282 _rw_space->bottom());
1283 }
1284
1285 // Write the oop data to the output array.
1286
1287 WriteClosure wc(md_top, md_end);
1288 CompactingPermGenGen::serialize_oops(&wc);
1289 md_top = wc.get_top();
1290
1291 // Update the vtable pointers in all of the Klass objects in the
1292 // heap. They should point to newly generated vtable.
1293
1294 PatchKlassVtables pkvt;
1295 _rw_space->object_iterate(&pkvt);
1296 pkvt.patch(vtbl_list, vtable);
1297
1298 #ifndef PRODUCT
1299 // Update the vtable pointers in all symbols,
1300 // but only in non-product builds where symbols DO have virtual methods.
1301 PatchSymbolVtables psvt(vtbl_list, vtable);
1302 SymbolTable::symbols_do(&psvt);
1303 #endif
1304
1305 char* saved_vtbl = (char*)malloc(vtbl_list_size * sizeof(void*));
1306 memmove(saved_vtbl, vtbl_list, vtbl_list_size * sizeof(void*));
1307 memset(vtbl_list, 0, vtbl_list_size * sizeof(void*));
1308
1309 // Create and write the archive file that maps the shared spaces.
1310
1311 FileMapInfo* mapinfo = new FileMapInfo();
1312 mapinfo->populate_header(gch->gen_policy()->max_alignment());
1313
1314 // Pass 1 - update file offsets in header.
1315 mapinfo->write_header();
1316 mapinfo->write_space(CompactingPermGenGen::ro, _ro_space, true);
1317 _ro_space->set_saved_mark();
1318 mapinfo->write_space(CompactingPermGenGen::rw, _rw_space, false);
1319 _rw_space->set_saved_mark();
1320 mapinfo->write_region(CompactingPermGenGen::md, _md_vs->low(),
1321 pointer_delta(md_top, _md_vs->low(), sizeof(char)),
1322 SharedMiscDataSize,
1323 false, false);
1324 mapinfo->write_region(CompactingPermGenGen::mc, _mc_vs->low(),
1325 pointer_delta(mc_top, _mc_vs->low(), sizeof(char)),
1326 SharedMiscCodeSize,
1327 true, true);
1328
1329 // Pass 2 - write data.
1330 mapinfo->open_for_write();
1331 mapinfo->write_header();
1332 mapinfo->write_space(CompactingPermGenGen::ro, _ro_space, true);
1333 mapinfo->write_space(CompactingPermGenGen::rw, _rw_space, false);
1334 mapinfo->write_region(CompactingPermGenGen::md, _md_vs->low(),
1335 pointer_delta(md_top, _md_vs->low(), sizeof(char)),
1336 SharedMiscDataSize,
1337 false, false);
1338 mapinfo->write_region(CompactingPermGenGen::mc, _mc_vs->low(),
1339 pointer_delta(mc_top, _mc_vs->low(), sizeof(char)),
1340 SharedMiscCodeSize,
1341 true, true);
1342 mapinfo->close();
1343
1344 // Summarize heap.
1345 memmove(vtbl_list, saved_vtbl, vtbl_list_size * sizeof(void*));
1346 print_contents();
1347 }
1348 }; // class VM_PopulateDumpSharedSpace
1349
1350
1351 // Populate the shared spaces and dump to a file.
1352
1353 jint CompactingPermGenGen::dump_shared(GrowableArray<oop>* class_promote_order, TRAPS) {
1354 GenCollectedHeap* gch = GenCollectedHeap::heap();
1355
1356 // Calculate hash values for all of the (interned) strings to avoid
1357 // writes to shared pages in the future.
1358
1359 tty->print("Calculating hash values for String objects .. ");
1360 StringHashCodeClosure shcc(THREAD);
1361 StringTable::oops_do(&shcc);
1362 tty->print_cr("done. ");
1363
1364 CompactingPermGenGen* gen = (CompactingPermGenGen*)gch->perm_gen();
1365 VM_PopulateDumpSharedSpace op(class_promote_order,
1366 gen->ro_space(), gen->rw_space(),
1367 gen->md_space(), gen->mc_space());
1368 VMThread::execute(&op);
1369 return JNI_OK;
1370 }
1371
1372 void* CompactingPermGenGen::find_matching_vtbl_ptr(void** vtbl_list,
1373 void* new_vtable_start,
1374 void* obj) {
1375 void* old_vtbl_ptr = *(void**)obj;
1376 for (int i = 0; i < vtbl_list_size; i++) {
1377 if (vtbl_list[i] == old_vtbl_ptr) {
1378 return (void**)new_vtable_start + i * num_virtuals;
1379 }
1380 }
1381 ShouldNotReachHere();
1382 return NULL;
1383 }
1384
1385
1386 class LinkClassesClosure : public ObjectClosure {
1387 private:
1388 Thread* THREAD;
1389
1390 public:
1391 LinkClassesClosure(Thread* thread) : THREAD(thread) {}
1392
1393 void do_object(oop obj) {
1394 if (obj->is_klass()) {
1395 Klass* k = Klass::cast((klassOop) obj);
1396 if (k->oop_is_instance()) {
1397 instanceKlass* ik = (instanceKlass*) k;
1398 // Link the class to cause the bytecodes to be rewritten and the
1399 // cpcache to be created.
1400 if (ik->init_state() < instanceKlass::linked) {
1401 ik->link_class(THREAD);
1402 guarantee(!HAS_PENDING_EXCEPTION, "exception in class rewriting");
1403 }
1404
1405 // Create String objects from string initializer symbols.
1406 ik->constants()->resolve_string_constants(THREAD);
1407 guarantee(!HAS_PENDING_EXCEPTION, "exception resolving string constants");
1408 }
1409 }
1410 }
1411 };
1412
1413
1414 // Support for a simple checksum of the contents of the class list
1415 // file to prevent trivial tampering. The algorithm matches that in
1416 // the MakeClassList program used by the J2SE build process.
1417 #define JSUM_SEED ((jlong)CONST64(0xcafebabebabecafe))
1418 static jlong
1419 jsum(jlong start, const char *buf, const int len)
1420 {
1421 jlong h = start;
1422 char *p = (char *)buf, *e = p + len;
1423 while (p < e) {
1424 char c = *p++;
1425 if (c <= ' ') {
1426 /* Skip spaces and control characters */
1427 continue;
1428 }
1429 h = 31 * h + c;
1430 }
1431 return h;
1432 }
1433
1434
1435
1436
1437
1438 // Preload classes from a list, populate the shared spaces and dump to a
1439 // file.
1440
1441 void GenCollectedHeap::preload_and_dump(TRAPS) {
1442 TraceTime timer("Dump Shared Spaces", TraceStartupTime);
1443 ResourceMark rm;
1444
1445 // Preload classes to be shared.
1446 // Should use some os:: method rather than fopen() here. aB.
1447 // Construct the path to the class list (in jre/lib)
1448 // Walk up two directories from the location of the VM and
1449 // optionally tack on "lib" (depending on platform)
1450 char class_list_path[JVM_MAXPATHLEN];
1451 os::jvm_path(class_list_path, sizeof(class_list_path));
1452 for (int i = 0; i < 3; i++) {
1453 char *end = strrchr(class_list_path, *os::file_separator());
1454 if (end != NULL) *end = '\0';
1455 }
1456 int class_list_path_len = (int)strlen(class_list_path);
1457 if (class_list_path_len >= 3) {
1458 if (strcmp(class_list_path + class_list_path_len - 3, "lib") != 0) {
1459 strcat(class_list_path, os::file_separator());
1460 strcat(class_list_path, "lib");
1461 }
1462 }
1463 strcat(class_list_path, os::file_separator());
1464 strcat(class_list_path, "classlist");
1465
1466 FILE* file = fopen(class_list_path, "r");
1467 if (file != NULL) {
1468 jlong computed_jsum = JSUM_SEED;
1469 jlong file_jsum = 0;
1470
1471 char class_name[256];
1472 int class_count = 0;
1473 GenCollectedHeap* gch = GenCollectedHeap::heap();
1474 gch->_preloading_shared_classes = true;
1475 GrowableArray<oop>* class_promote_order = new GrowableArray<oop>();
1476
1477 // Preload (and intern) strings which will be used later.
1478
1479 StringTable::intern("main", THREAD);
1480 StringTable::intern("([Ljava/lang/String;)V", THREAD);
1481 StringTable::intern("Ljava/lang/Class;", THREAD);
1482
1483 StringTable::intern("I", THREAD); // Needed for StringBuffer persistence?
1484 StringTable::intern("Z", THREAD); // Needed for StringBuffer persistence?
1485
1486 // sun.io.Converters
1487 static const char obj_array_sig[] = "[[Ljava/lang/Object;";
1488 (void)SymbolTable::new_permanent_symbol(obj_array_sig, THREAD);
1489
1490 // java.util.HashMap
1491 static const char map_entry_array_sig[] = "[Ljava/util/Map$Entry;";
1492 (void)SymbolTable::new_permanent_symbol(map_entry_array_sig, THREAD);
1493
1494 tty->print("Loading classes to share ... ");
1495 while ((fgets(class_name, sizeof class_name, file)) != NULL) {
1496 if (*class_name == '#') {
1497 jint fsh, fsl;
1498 if (sscanf(class_name, "# %8x%8x\n", &fsh, &fsl) == 2) {
1499 file_jsum = ((jlong)(fsh) << 32) | (fsl & 0xffffffff);
1500 }
1501
1502 continue;
1503 }
1504 // Remove trailing newline
1505 size_t name_len = strlen(class_name);
1506 class_name[name_len-1] = '\0';
1507
1508 computed_jsum = jsum(computed_jsum, class_name, (const int)name_len - 1);
1509
1510 // Got a class name - load it.
1511 Symbol* class_name_symbol = SymbolTable::new_permanent_symbol(class_name, THREAD);
1512 guarantee(!HAS_PENDING_EXCEPTION, "Exception creating a symbol.");
1513 klassOop klass = SystemDictionary::resolve_or_null(class_name_symbol,
1514 THREAD);
1515 guarantee(!HAS_PENDING_EXCEPTION, "Exception resolving a class.");
1516 if (klass != NULL) {
1517 if (PrintSharedSpaces) {
1518 tty->print_cr("Shared spaces preloaded: %s", class_name);
1519 }
1520
1521
1522 instanceKlass* ik = instanceKlass::cast(klass);
1523
1524 // Should be class load order as per -XX:+TraceClassLoadingPreorder
1525 class_promote_order->append(ik->as_klassOop());
1526
1527 // Link the class to cause the bytecodes to be rewritten and the
1528 // cpcache to be created. The linking is done as soon as classes
1529 // are loaded in order that the related data structures (klass,
1530 // cpCache, Sting constants) are located together.
1531
1532 if (ik->init_state() < instanceKlass::linked) {
1533 ik->link_class(THREAD);
1534 guarantee(!(HAS_PENDING_EXCEPTION), "exception in class rewriting");
1535 }
1536
1537 // Create String objects from string initializer symbols.
1538
1539 ik->constants()->resolve_string_constants(THREAD);
1540
1541 class_count++;
1542 } else {
1543 if (PrintSharedSpaces) {
1544 tty->cr();
1545 tty->print_cr(" Preload failed: %s", class_name);
1546 }
1547 }
1548 file_jsum = 0; // Checksum must be on last line of file
1549 }
1550 if (computed_jsum != file_jsum) {
1551 tty->cr();
1552 tty->print_cr("Preload failed: checksum of class list was incorrect.");
1553 exit(1);
1554 }
1555
1556 tty->print_cr("done. ");
1557
1558 if (PrintSharedSpaces) {
1559 tty->print_cr("Shared spaces: preloaded %d classes", class_count);
1560 }
1561
1562 // Rewrite and unlink classes.
1563 tty->print("Rewriting and unlinking classes ... ");
1564 // Make heap parsable
1565 ensure_parsability(false); // arg is actually don't care
1566
1567 // Link any classes which got missed. (It's not quite clear why
1568 // they got missed.) This iteration would be unsafe if we weren't
1569 // single-threaded at this point; however we can't do it on the VM
1570 // thread because it requires object allocation.
1571 LinkClassesClosure lcc(Thread::current());
1572 object_iterate(&lcc);
1573 ensure_parsability(false); // arg is actually don't care
1574 tty->print_cr("done. ");
1575
1576 // Create and dump the shared spaces.
1577 jint err = CompactingPermGenGen::dump_shared(class_promote_order, THREAD);
1578 if (err != JNI_OK) {
1579 fatal("Dumping shared spaces failed.");
1580 }
1581
1582 } else {
1583 char errmsg[JVM_MAXPATHLEN];
1584 os::lasterror(errmsg, JVM_MAXPATHLEN);
1585 tty->print_cr("Loading classlist failed: %s", errmsg);
1586 exit(1);
1587 }
1588
1589 // Since various initialization steps have been undone by this process,
1590 // it is not reasonable to continue running a java process.
1591 exit(0);
1592 }