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 // Exception tables are needed by ci code during compilation.
235 mark_object(constMethodOop(obj)->exception_table());
236 }
237
238 // Mark objects referenced by klass objects which are read-only.
239
240 else if (obj->is_klass()) {
241 Klass* k = Klass::cast((klassOop)obj);
242 mark_object(k->secondary_supers());
243
244 // The METHODS() OBJARRAYS CANNOT BE MADE READ-ONLY, even though
245 // it is never modified. Otherwise, they will be pre-marked; the
246 // GC marking phase will skip them; and by skipping them will fail
247 // to mark the methods objects referenced by the array.
248
249 if (obj->blueprint()->oop_is_instanceKlass()) {
250 instanceKlass* ik = instanceKlass::cast((klassOop)obj);
251 mark_object(ik->method_ordering());
252 mark_object(ik->local_interfaces());
253 mark_object(ik->transitive_interfaces());
254 mark_object(ik->fields());
255
256 mark_object(ik->class_annotations());
257
258 mark_object_recursive_skipping_klasses(ik->fields_annotations());
259 mark_object_recursive_skipping_klasses(ik->methods_annotations());
260 mark_object_recursive_skipping_klasses(ik->methods_parameter_annotations());
261 mark_object_recursive_skipping_klasses(ik->methods_default_annotations());
262
263 typeArrayOop inner_classes = ik->inner_classes();
264 if (inner_classes != NULL) {
265 mark_object(inner_classes);
266 }
267 }
268 }
269 }
270 };
271
272
273 // Closure: find symbol references in Java Heap objects
274
275 class CommonSymbolsClosure : public ObjectClosure {
276 private:
277 SymbolClosure* _closure;
278 public:
279 CommonSymbolsClosure(SymbolClosure* closure) : _closure(closure) { }
280
281 void do_object(oop obj) {
282
283 // Traverse symbols referenced by method objects.
284
285 if (obj->is_method()) {
286 methodOop m = methodOop(obj);
287 constantPoolOop constants = m->constants();
288 _closure->do_symbol(constants->symbol_at_addr(m->name_index()));
289 _closure->do_symbol(constants->symbol_at_addr(m->signature_index()));
290 }
291
292 // Traverse symbols referenced by klass objects which are read-only.
293
294 else if (obj->is_klass()) {
295 Klass* k = Klass::cast((klassOop)obj);
296 k->shared_symbols_iterate(_closure);
297
298 if (obj->blueprint()->oop_is_instanceKlass()) {
299 instanceKlass* ik = instanceKlass::cast((klassOop)obj);
300 instanceKlassHandle ik_h((klassOop)obj);
301 InnerClassesIterator iter(ik_h);
302 constantPoolOop constants = ik->constants();
303 for (; !iter.done(); iter.next()) {
304 int index = iter.inner_name_index();
305
306 if (index != 0) {
307 _closure->do_symbol(constants->symbol_at_addr(index));
308 }
309 }
310 }
311 }
312
313 // Traverse symbols referenced by other constantpool entries.
314
315 else if (obj->is_constantPool()) {
316 constantPoolOop(obj)->shared_symbols_iterate(_closure);
317 }
318 }
319 };
320
321
322 // Closure: mark char arrays used by strings
323
324 class MarkStringValues : public ObjectClosure {
325 private:
326 MarkObjectsOopClosure mark_all;
327 public:
328 void do_object(oop obj) {
329
330 // Character arrays referenced by String objects are read-only.
331
332 if (java_lang_String::is_instance(obj)) {
333 mark_object(java_lang_String::value(obj));
334 }
335 }
336 };
337
338
339 #ifdef DEBUG
340 // Closure: Check for objects left in the heap which have not been moved.
341
342 class CheckRemainingObjects : public ObjectClosure {
343 private:
344 int count;
345
346 public:
347 CheckRemainingObjects() {
348 count = 0;
349 }
350
351 void do_object(oop obj) {
352 if (!obj->is_shared() &&
353 !obj->is_forwarded()) {
354 ++count;
355 if (Verbose) {
356 tty->print("Unreferenced object: ");
357 obj->print_on(tty);
358 }
359 }
360 }
361
362 void status() {
363 tty->print_cr("%d objects no longer referenced, not shared.", count);
364 }
365 };
366 #endif
367
368
369 // Closure: Mark remaining objects read-write, except Strings.
370
371 class MarkReadWriteObjects : public ObjectClosure {
372 private:
373 MarkObjectsOopClosure mark_objects;
374 public:
375 void do_object(oop obj) {
376
377 // The METHODS() OBJARRAYS CANNOT BE MADE READ-ONLY, even though
378 // it is never modified. Otherwise, they will be pre-marked; the
379 // GC marking phase will skip them; and by skipping them will fail
380 // to mark the methods objects referenced by the array.
381
382 if (obj->is_klass()) {
383 mark_object(obj);
384 Klass* k = klassOop(obj)->klass_part();
385 mark_object(k->java_mirror());
386 if (obj->blueprint()->oop_is_instanceKlass()) {
387 instanceKlass* ik = (instanceKlass*)k;
388 mark_object(ik->methods());
389 mark_object(ik->constants());
390 }
391 if (obj->blueprint()->oop_is_javaArray()) {
392 arrayKlass* ak = (arrayKlass*)k;
393 mark_object(ak->component_mirror());
394 }
395 return;
396 }
397
398 // Mark constantPool tags and the constantPoolCache.
399
400 else if (obj->is_constantPool()) {
401 constantPoolOop pool = constantPoolOop(obj);
402 mark_object(pool->cache());
403 pool->shared_tags_iterate(&mark_objects);
404 return;
405 }
406
407 // Mark all method objects.
408
409 if (obj->is_method()) {
410 mark_object(obj);
411 }
412 }
413 };
414
415
416 // Closure: Mark String objects read-write.
417
418 class MarkStringObjects : public ObjectClosure {
419 private:
420 MarkObjectsOopClosure mark_objects;
421 public:
422 void do_object(oop obj) {
423
424 // Mark String objects referenced by constant pool entries.
425
426 if (obj->is_constantPool()) {
427 constantPoolOop pool = constantPoolOop(obj);
428 pool->shared_strings_iterate(&mark_objects);
429 return;
430 }
431 }
432 };
433
434
435 // Move objects matching specified type (ie. lock_bits) to the specified
436 // space.
437
438 class MoveMarkedObjects : public ObjectClosure {
439 private:
440 OffsetTableContigSpace* _space;
441 bool _read_only;
442
443 public:
444 MoveMarkedObjects(OffsetTableContigSpace* space, bool read_only) {
445 _space = space;
446 _read_only = read_only;
447 }
448
449 void do_object(oop obj) {
450 if (obj->is_shared()) {
451 return;
452 }
453 if (obj->is_gc_marked() && obj->forwardee() == NULL) {
454 int s = obj->size();
455 oop sh_obj = (oop)_space->allocate(s);
456 if (sh_obj == NULL) {
457 report_out_of_shared_space(_read_only ? SharedReadOnly : SharedReadWrite);
458 }
459 if (PrintSharedSpaces && Verbose && WizardMode) {
460 tty->print_cr("\nMoveMarkedObjects: " PTR_FORMAT " -> " PTR_FORMAT " %s", obj, sh_obj,
461 (_read_only ? "ro" : "rw"));
462 }
463 Copy::aligned_disjoint_words((HeapWord*)obj, (HeapWord*)sh_obj, s);
464 obj->forward_to(sh_obj);
465 if (_read_only) {
466 // Readonly objects: set hash value to self pointer and make gc_marked.
467 sh_obj->forward_to(sh_obj);
468 } else {
469 sh_obj->init_mark();
470 }
471 }
472 }
473 };
474
475 static void mark_and_move(oop obj, MoveMarkedObjects* move) {
476 if (mark_object(obj)) move->do_object(obj);
477 }
478
479 enum order_policy {
480 OP_favor_startup = 0,
481 OP_balanced = 1,
482 OP_favor_runtime = 2
483 };
484
485 static void mark_and_move_for_policy(order_policy policy, oop obj, MoveMarkedObjects* move) {
486 if (SharedOptimizeColdStartPolicy >= policy) mark_and_move(obj, move);
487 }
488
489 class MarkAndMoveOrderedReadOnly : public ObjectClosure {
490 private:
491 MoveMarkedObjects *_move_ro;
492
493 public:
494 MarkAndMoveOrderedReadOnly(MoveMarkedObjects *move_ro) : _move_ro(move_ro) {}
495
496 void do_object(oop obj) {
497 if (obj->is_klass() && obj->blueprint()->oop_is_instanceKlass()) {
498 instanceKlass* ik = instanceKlass::cast((klassOop)obj);
499 int i;
500
501 if (ik->super() != NULL) {
502 do_object(ik->super());
503 }
504
505 objArrayOop interfaces = ik->local_interfaces();
506 mark_and_move_for_policy(OP_favor_startup, interfaces, _move_ro);
507 for(i = 0; i < interfaces->length(); i++) {
508 klassOop k = klassOop(interfaces->obj_at(i));
509 do_object(k);
510 }
511
512 objArrayOop methods = ik->methods();
513 for(i = 0; i < methods->length(); i++) {
514 methodOop m = methodOop(methods->obj_at(i));
515 mark_and_move_for_policy(OP_favor_startup, m->constMethod(), _move_ro);
516 mark_and_move_for_policy(OP_favor_runtime, m->constMethod()->exception_table(), _move_ro);
517 mark_and_move_for_policy(OP_favor_runtime, m->constMethod()->stackmap_data(), _move_ro);
518 }
519
520 mark_and_move_for_policy(OP_favor_startup, ik->transitive_interfaces(), _move_ro);
521 mark_and_move_for_policy(OP_favor_startup, ik->fields(), _move_ro);
522
523 mark_and_move_for_policy(OP_favor_runtime, ik->secondary_supers(), _move_ro);
524 mark_and_move_for_policy(OP_favor_runtime, ik->method_ordering(), _move_ro);
525 mark_and_move_for_policy(OP_favor_runtime, ik->class_annotations(), _move_ro);
526 mark_and_move_for_policy(OP_favor_runtime, ik->fields_annotations(), _move_ro);
527 mark_and_move_for_policy(OP_favor_runtime, ik->methods_annotations(), _move_ro);
528 mark_and_move_for_policy(OP_favor_runtime, ik->methods_parameter_annotations(), _move_ro);
529 mark_and_move_for_policy(OP_favor_runtime, ik->methods_default_annotations(), _move_ro);
530 mark_and_move_for_policy(OP_favor_runtime, ik->inner_classes(), _move_ro);
531 mark_and_move_for_policy(OP_favor_runtime, ik->secondary_supers(), _move_ro);
532 }
533 }
534 };
535
536 class MarkAndMoveOrderedReadWrite: public ObjectClosure {
537 private:
538 MoveMarkedObjects *_move_rw;
539
540 public:
541 MarkAndMoveOrderedReadWrite(MoveMarkedObjects *move_rw) : _move_rw(move_rw) {}
542
543 void do_object(oop obj) {
544 if (obj->is_klass() && obj->blueprint()->oop_is_instanceKlass()) {
545 instanceKlass* ik = instanceKlass::cast((klassOop)obj);
546 int i;
547
548 mark_and_move_for_policy(OP_favor_startup, ik->as_klassOop(), _move_rw);
549
550 if (ik->super() != NULL) {
551 do_object(ik->super());
552 }
553
554 objArrayOop interfaces = ik->local_interfaces();
555 for(i = 0; i < interfaces->length(); i++) {
556 klassOop k = klassOop(interfaces->obj_at(i));
557 mark_and_move_for_policy(OP_favor_startup, k, _move_rw);
558 do_object(k);
559 }
560
561 objArrayOop methods = ik->methods();
562 mark_and_move_for_policy(OP_favor_startup, methods, _move_rw);
563 for(i = 0; i < methods->length(); i++) {
564 methodOop m = methodOop(methods->obj_at(i));
565 mark_and_move_for_policy(OP_favor_startup, m, _move_rw);
566 mark_and_move_for_policy(OP_favor_startup, ik->constants(), _move_rw); // idempotent
567 mark_and_move_for_policy(OP_balanced, ik->constants()->cache(), _move_rw); // idempotent
568 mark_and_move_for_policy(OP_balanced, ik->constants()->tags(), _move_rw); // idempotent
569 }
570
571 mark_and_move_for_policy(OP_favor_startup, ik->as_klassOop()->klass(), _move_rw);
572 mark_and_move_for_policy(OP_favor_startup, ik->constants()->klass(), _move_rw);
573
574 // Although Java mirrors are marked in MarkReadWriteObjects,
575 // apparently they were never moved into shared spaces since
576 // MoveMarkedObjects skips marked instance oops. This may
577 // be a bug in the original implementation or simply the vestige
578 // of an abandoned experiment. Nevertheless we leave a hint
579 // here in case this capability is ever correctly implemented.
580 //
581 // mark_and_move_for_policy(OP_favor_runtime, ik->java_mirror(), _move_rw);
582 }
583 }
584
585 };
586
587 // Adjust references in oops to refer to shared spaces.
588
589 class ResolveForwardingClosure: public OopClosure {
590 public:
591 void do_oop(oop* p) {
592 oop obj = *p;
593 if (!obj->is_shared()) {
594 if (obj != NULL) {
595 oop f = obj->forwardee();
596 guarantee(f->is_shared(), "Oop doesn't refer to shared space.");
597 *p = f;
598 }
599 }
600 }
601 void do_oop(narrowOop* pobj) { ShouldNotReachHere(); }
602 };
603
604
605 // The methods array must be reordered by Symbol* address.
606 // (See classFileParser.cpp where methods in a class are originally
607 // sorted). The addresses of symbols have been changed as a result
608 // of moving to the shared space.
609
610 class SortMethodsClosure: public ObjectClosure {
611 public:
612 void do_object(oop obj) {
613 if (obj->blueprint()->oop_is_instanceKlass()) {
614 instanceKlass* ik = instanceKlass::cast((klassOop)obj);
615 methodOopDesc::sort_methods(ik->methods(),
616 ik->methods_annotations(),
617 ik->methods_parameter_annotations(),
618 ik->methods_default_annotations(),
619 true /* idempotent, slow */);
620 }
621 }
622 };
623
624 // Vtable and Itable indices are calculated based on methods array
625 // order (see klassItable::compute_itable_index()). Must reinitialize
626 // after ALL methods of ALL classes have been reordered.
627 // We assume that since checkconstraints is false, this method
628 // cannot throw an exception. An exception here would be
629 // problematic since this is the VMThread, not a JavaThread.
630
631 class ReinitializeTables: public ObjectClosure {
632 private:
633 Thread* _thread;
634
635 public:
636 ReinitializeTables(Thread* thread) : _thread(thread) {}
637
638 // Initialize super vtable first, check if already initialized to avoid
639 // quadradic behavior. The vtable is cleared in remove_unshareable_info.
640 void reinitialize_vtables(klassOop k) {
641 if (k->blueprint()->oop_is_instanceKlass()) {
642 instanceKlass* ik = instanceKlass::cast(k);
643 if (ik->vtable()->is_initialized()) return;
644 if (ik->super() != NULL) {
645 reinitialize_vtables(ik->super());
646 }
647 ik->vtable()->initialize_vtable(false, _thread);
648 }
649 }
650
651 void do_object(oop obj) {
652 if (obj->blueprint()->oop_is_instanceKlass()) {
653 instanceKlass* ik = instanceKlass::cast((klassOop)obj);
654 ResourceMark rm(_thread);
655 ik->itable()->initialize_itable(false, _thread);
656 reinitialize_vtables((klassOop)obj);
657 #ifdef ASSERT
658 ik->vtable()->verify(tty, true);
659 #endif // ASSERT
660 } else if (obj->blueprint()->oop_is_arrayKlass()) {
661 // The vtable for array klasses are that of its super class,
662 // ie. java.lang.Object.
663 arrayKlass* ak = arrayKlass::cast((klassOop)obj);
664 if (ak->vtable()->is_initialized()) return;
665 ak->vtable()->initialize_vtable(false, _thread);
666 }
667 }
668 };
669
670
671 // Adjust references in oops to refer to shared spaces.
672
673 class PatchOopsClosure: public ObjectClosure {
674 private:
675 Thread* _thread;
676 ResolveForwardingClosure resolve;
677
678 public:
679 PatchOopsClosure(Thread* thread) : _thread(thread) {}
680
681 void do_object(oop obj) {
682 obj->oop_iterate_header(&resolve);
683 obj->oop_iterate(&resolve);
684
685 assert(obj->klass()->is_shared(), "Klass not pointing into shared space.");
686
687 // If the object is a Java object or class which might (in the
688 // future) contain a reference to a young gen object, add it to the
689 // list.
690
691 if (obj->is_klass() || obj->is_instance()) {
692 if (obj->is_klass() ||
693 obj->is_a(SystemDictionary::Class_klass()) ||
694 obj->is_a(SystemDictionary::Throwable_klass())) {
695 // Do nothing
696 }
697 else if (obj->is_a(SystemDictionary::String_klass())) {
698 // immutable objects.
699 } else {
700 // someone added an object we hadn't accounted for.
701 ShouldNotReachHere();
702 }
703 }
704 }
705 };
706
707
708 // Empty the young and old generations.
709
710 class ClearSpaceClosure : public SpaceClosure {
711 public:
712 void do_space(Space* s) {
713 s->clear(SpaceDecorator::Mangle);
714 }
715 };
716
717
718 // Closure for serializing initialization data out to a data area to be
719 // written to the shared file.
720
721 class WriteClosure : public SerializeOopClosure {
722 private:
723 oop* top;
724 char* end;
725
726 inline void check_space() {
727 if ((char*)top + sizeof(oop) > end) {
728 report_out_of_shared_space(SharedMiscData);
729 }
730 }
731
732
733 public:
734 WriteClosure(char* md_top, char* md_end) {
735 top = (oop*)md_top;
736 end = md_end;
737 }
738
739 char* get_top() { return (char*)top; }
740
741 void do_oop(oop* p) {
742 check_space();
743 oop obj = *p;
744 assert(obj->is_oop_or_null(), "invalid oop");
745 assert(obj == NULL || obj->is_shared(),
746 "Oop in shared space not pointing into shared space.");
747 *top = obj;
748 ++top;
749 }
750
751 void do_oop(narrowOop* pobj) { ShouldNotReachHere(); }
752
753 void do_int(int* p) {
754 check_space();
755 *top = (oop)(intptr_t)*p;
756 ++top;
757 }
758
759 void do_size_t(size_t* p) {
760 check_space();
761 *top = (oop)(intptr_t)*p;
762 ++top;
763 }
764
765 void do_ptr(void** p) {
766 check_space();
767 *top = (oop)*p;
768 ++top;
769 }
770
771 void do_ptr(HeapWord** p) { do_ptr((void **) p); }
772
773 void do_tag(int tag) {
774 check_space();
775 *top = (oop)(intptr_t)tag;
776 ++top;
777 }
778
779 void do_region(u_char* start, size_t size) {
780 if ((char*)top + size > end) {
781 report_out_of_shared_space(SharedMiscData);
782 }
783 assert((intptr_t)start % sizeof(oop) == 0, "bad alignment");
784 assert(size % sizeof(oop) == 0, "bad size");
785 do_tag((int)size);
786 while (size > 0) {
787 *top = *(oop*)start;
788 ++top;
789 start += sizeof(oop);
790 size -= sizeof(oop);
791 }
792 }
793
794 bool reading() const { return false; }
795 };
796
797
798 class ResolveConstantPoolsClosure : public ObjectClosure {
799 private:
800 TRAPS;
801 public:
802 ResolveConstantPoolsClosure(Thread *t) {
803 __the_thread__ = t;
804 }
805 void do_object(oop obj) {
806 if (obj->is_constantPool()) {
807 constantPoolOop cpool = (constantPoolOop)obj;
808 int unresolved = cpool->pre_resolve_shared_klasses(THREAD);
809 }
810 }
811 };
812
813
814 // Print a summary of the contents of the read/write spaces to help
815 // identify objects which might be able to be made read-only. At this
816 // point, the objects have been written, and we can trash them as
817 // needed.
818
819 static void print_contents() {
820 if (PrintSharedSpaces) {
821 GenCollectedHeap* gch = GenCollectedHeap::heap();
822 CompactingPermGenGen* gen = (CompactingPermGenGen*)gch->perm_gen();
823
824 // High level summary of the read-only space:
825
826 ClassifyObjectClosure coc;
827 tty->cr(); tty->print_cr("ReadOnly space:");
828 gen->ro_space()->object_iterate(&coc);
829 coc.print();
830
831 // High level summary of the read-write space:
832
833 coc.reset();
834 tty->cr(); tty->print_cr("ReadWrite space:");
835 gen->rw_space()->object_iterate(&coc);
836 coc.print();
837
838 // Reset counters
839
840 ClearAllocCountClosure cacc;
841 gen->ro_space()->object_iterate(&cacc);
842 gen->rw_space()->object_iterate(&cacc);
843 coc.reset();
844
845 // Lower level summary of the read-only space:
846
847 gen->ro_space()->object_iterate(&coc);
848 tty->cr(); tty->print_cr("ReadOnly space:");
849 ClassifyInstanceKlassClosure cikc;
850 gen->rw_space()->object_iterate(&cikc);
851 cikc.print();
852
853 // Reset counters
854
855 gen->ro_space()->object_iterate(&cacc);
856 gen->rw_space()->object_iterate(&cacc);
857 coc.reset();
858
859 // Lower level summary of the read-write space:
860
861 gen->rw_space()->object_iterate(&coc);
862 cikc.reset();
863 tty->cr(); tty->print_cr("ReadWrite space:");
864 gen->rw_space()->object_iterate(&cikc);
865 cikc.print();
866 }
867 }
868
869
870 // Patch C++ vtable pointer in klass oops.
871
872 // Klass objects contain references to c++ vtables in the JVM library.
873 // Fix them to point to our constructed vtables. However, don't iterate
874 // across the space while doing this, as that causes the vtables to be
875 // patched, undoing our useful work. Instead, iterate to make a list,
876 // then use the list to do the fixing.
877 //
878 // Our constructed vtables:
879 // Dump time:
880 // 1. init_self_patching_vtbl_list: table of pointers to current virtual method addrs
881 // 2. generate_vtable_methods: create jump table, appended to above vtbl_list
882 // 3. PatchKlassVtables: for Klass list, patch the vtable entry to point to jump table
883 // rather than to current vtbl
884 // Table layout: NOTE FIXED SIZE
885 // 1. vtbl pointers
886 // 2. #Klass X #virtual methods per Klass
887 // 1 entry for each, in the order:
888 // Klass1:method1 entry, Klass1:method2 entry, ... Klass1:method<num_virtuals> entry
889 // Klass2:method1 entry, Klass2:method2 entry, ... Klass2:method<num_virtuals> entry
890 // ...
891 // Klass<vtbl_list_size>:method1 entry, Klass<vtbl_list_size>:method2 entry,
892 // ... Klass<vtbl_list_size>:method<num_virtuals> entry
893 // Sample entry: (Sparc):
894 // save(sp, -256, sp)
895 // ba,pt common_code
896 // mov XXX, %L0 %L0 gets: Klass index <<8 + method index (note: max method index 255)
897 //
898 // Restore time:
899 // 1. initialize_oops: reserve space for table
900 // 2. init_self_patching_vtbl_list: update pointers to NEW virtual method addrs in text
901 //
902 // Execution time:
903 // First virtual method call for any object of these Klass types:
904 // 1. object->klass->klass_part
905 // 2. vtable entry for that klass_part points to the jump table entries
906 // 3. branches to common_code with %O0/klass_part, %L0: Klass index <<8 + method index
907 // 4. common_code:
908 // Get address of new vtbl pointer for this Klass from updated table
909 // Update new vtbl pointer in the Klass: future virtual calls go direct
910 // Jump to method, using new vtbl pointer and method index
911
912 class PatchKlassVtables: public ObjectClosure {
913 private:
914 GrowableArray<klassOop>* _klass_objects;
915
916 public:
917 PatchKlassVtables() {
918 _klass_objects = new GrowableArray<klassOop>();
919 }
920
921 void do_object(oop obj) {
922 if (obj->is_klass()) {
923 _klass_objects->append(klassOop(obj));
924 }
925 }
926
927 void patch(void** vtbl_list, void* new_vtable_start) {
928 int n = _klass_objects->length();
929 for (int i = 0; i < n; i++) {
930 klassOop obj = (klassOop)_klass_objects->at(i);
931 Klass* k = obj->klass_part();
932 *(void**)k = CompactingPermGenGen::find_matching_vtbl_ptr(
933 vtbl_list, new_vtable_start, k);
934 }
935 }
936 };
937
938 // Walk through all symbols and patch their vtable pointers.
939 // Note that symbols have vtable pointers only in non-product builds
940 // (see allocation.hpp).
941
942 #ifndef PRODUCT
943 class PatchSymbolVtables: public SymbolClosure {
944 private:
945 void* _new_vtbl_ptr;
946
947 public:
948 PatchSymbolVtables(void** vtbl_list, void* new_vtable_start) {
949 Symbol s;
950 _new_vtbl_ptr = CompactingPermGenGen::find_matching_vtbl_ptr(
951 vtbl_list, new_vtable_start, &s);
952 }
953
954 void do_symbol(Symbol** p) {
955 Symbol* sym = load_symbol(p);
956 *(void**)sym = _new_vtbl_ptr;
957 }
958 };
959 #endif
960
961
962 // Populate the shared space.
963
964 class VM_PopulateDumpSharedSpace: public VM_Operation {
965 private:
966 GrowableArray<oop> *_class_promote_order;
967 OffsetTableContigSpace* _ro_space;
968 OffsetTableContigSpace* _rw_space;
969 VirtualSpace* _md_vs;
970 VirtualSpace* _mc_vs;
971
972 public:
973 VM_PopulateDumpSharedSpace(GrowableArray<oop> *class_promote_order,
974 OffsetTableContigSpace* ro_space,
975 OffsetTableContigSpace* rw_space,
976 VirtualSpace* md_vs, VirtualSpace* mc_vs) {
977 _class_promote_order = class_promote_order;
978 _ro_space = ro_space;
979 _rw_space = rw_space;
980 _md_vs = md_vs;
981 _mc_vs = mc_vs;
982 }
983
984 VMOp_Type type() const { return VMOp_PopulateDumpSharedSpace; }
985 void doit() {
986 Thread* THREAD = VMThread::vm_thread();
987 NOT_PRODUCT(SystemDictionary::verify();)
988 // The following guarantee is meant to ensure that no loader constraints
989 // exist yet, since the constraints table is not shared. This becomes
990 // more important now that we don't re-initialize vtables/itables for
991 // shared classes at runtime, where constraints were previously created.
992 guarantee(SystemDictionary::constraints()->number_of_entries() == 0,
993 "loader constraints are not saved");
994 // Revisit and implement this if we prelink method handle call sites:
995 guarantee(SystemDictionary::invoke_method_table() == NULL ||
996 SystemDictionary::invoke_method_table()->number_of_entries() == 0,
997 "invoke method table is not saved");
998 GenCollectedHeap* gch = GenCollectedHeap::heap();
999
1000 // At this point, many classes have been loaded.
1001
1002 // Update all the fingerprints in the shared methods.
1003
1004 tty->print("Calculating fingerprints ... ");
1005 FingerprintMethodsClosure fpmc;
1006 gch->object_iterate(&fpmc);
1007 tty->print_cr("done. ");
1008
1009 // Remove all references outside the heap.
1010
1011 tty->print("Removing unshareable information ... ");
1012 RemoveUnshareableInfoClosure ruic;
1013 gch->object_iterate(&ruic);
1014 tty->print_cr("done. ");
1015
1016 // Move the objects in three passes.
1017
1018 MarkObjectsOopClosure mark_all;
1019 MarkCommonReadOnly mark_common_ro;
1020 MarkStringValues mark_string_values;
1021 MarkReadWriteObjects mark_rw;
1022 MarkStringObjects mark_strings;
1023 MoveMarkedObjects move_ro(_ro_space, true);
1024 MoveMarkedObjects move_rw(_rw_space, false);
1025
1026 // The SharedOptimizeColdStart VM option governs the new layout
1027 // algorithm for promoting classes into the shared archive.
1028 // The general idea is to minimize cold start time by laying
1029 // out the objects in the order they are accessed at startup time.
1030 // By doing this we are trying to eliminate out-of-order accesses
1031 // in the shared archive. This benefits cold startup time by making
1032 // disk reads as sequential as possible during class loading and
1033 // bootstrapping activities. There may also be a small secondary
1034 // effect of better "packing" of more commonly used data on a smaller
1035 // number of pages, although no direct benefit has been measured from
1036 // this effect.
1037 //
1038 // At the class level of granularity, the promotion order is dictated
1039 // by the classlist file whose generation is discussed elsewhere.
1040 //
1041 // At smaller granularity, optimal ordering was determined by an
1042 // offline analysis of object access order in the shared archive.
1043 // The dbx watchpoint facility, combined with SA post-processing,
1044 // was used to observe common access patterns primarily during
1045 // classloading. This information was used to craft the promotion
1046 // order seen in the following closures.
1047 //
1048 // The observed access order is mostly governed by what happens
1049 // in SystemDictionary::load_shared_class(). NOTE WELL - care
1050 // should be taken when making changes to this method, because it
1051 // may invalidate assumptions made about access order!
1052 //
1053 // (Ideally, there would be a better way to manage changes to
1054 // the access order. Unfortunately a generic in-VM solution for
1055 // dynamically observing access order and optimizing shared
1056 // archive layout is pretty difficult. We go with the static
1057 // analysis because the code is fairly mature at this point
1058 // and we're betting that the access order won't change much.)
1059
1060 MarkAndMoveOrderedReadOnly mark_and_move_ordered_ro(&move_ro);
1061 MarkAndMoveOrderedReadWrite mark_and_move_ordered_rw(&move_rw);
1062
1063 // Set up the share data and shared code segments.
1064
1065 char* md_top = _md_vs->low();
1066 char* md_end = _md_vs->high();
1067 char* mc_top = _mc_vs->low();
1068 char* mc_end = _mc_vs->high();
1069
1070 // Reserve space for the list of klassOops whose vtables are used
1071 // for patching others as needed.
1072
1073 void** vtbl_list = (void**)md_top;
1074 int vtbl_list_size = CompactingPermGenGen::vtbl_list_size;
1075 Universe::init_self_patching_vtbl_list(vtbl_list, vtbl_list_size);
1076
1077 md_top += vtbl_list_size * sizeof(void*);
1078 void* vtable = md_top;
1079
1080 // Reserve space for a new dummy vtable for klass objects in the
1081 // heap. Generate self-patching vtable entries.
1082
1083 CompactingPermGenGen::generate_vtable_methods(vtbl_list,
1084 &vtable,
1085 &md_top, md_end,
1086 &mc_top, mc_end);
1087
1088 // Reserve space for the total size and the number of stored symbols.
1089
1090 md_top += sizeof(intptr_t) * 2;
1091
1092 MoveSymbols move_symbols(md_top, md_end);
1093 CommonSymbolsClosure traverse_common_symbols(&move_symbols);
1094
1095 // Phase 1a: remove symbols with _refcount == 0
1096
1097 SymbolTable::unlink();
1098
1099 // Phase 1b: move commonly used symbols referenced by oop fields.
1100
1101 tty->print("Moving common symbols to metadata section at " PTR_FORMAT " ... ",
1102 move_symbols.get_top());
1103 gch->object_iterate(&traverse_common_symbols);
1104 tty->print_cr("done. ");
1105
1106 // Phase 1c: move known names and signatures.
1107
1108 tty->print("Moving vmSymbols to metadata section at " PTR_FORMAT " ... ",
1109 move_symbols.get_top());
1110 vmSymbols::symbols_do(&move_symbols);
1111 tty->print_cr("done. ");
1112
1113 // Phase 1d: move the remaining symbols by scanning the whole SymbolTable.
1114
1115 void* extra_symbols = move_symbols.get_top();
1116 tty->print("Moving the remaining symbols to metadata section at " PTR_FORMAT " ... ",
1117 move_symbols.get_top());
1118 SymbolTable::symbols_do(&move_symbols);
1119 tty->print_cr("done. ");
1120
1121 // Record the total length of all symbols at the beginning of the block.
1122 ((intptr_t*)md_top)[-2] = move_symbols.get_top() - md_top;
1123 ((intptr_t*)md_top)[-1] = move_symbols.count();
1124 tty->print_cr("Moved %d symbols, %d bytes.",
1125 move_symbols.count(), move_symbols.get_top() - md_top);
1126 // Advance the pointer to the end of symbol store.
1127 md_top = move_symbols.get_top();
1128
1129
1130 // Phase 2: move commonly used read-only objects to the read-only space.
1131
1132 if (SharedOptimizeColdStart) {
1133 tty->print("Moving pre-ordered read-only objects to shared space at " PTR_FORMAT " ... ",
1134 _ro_space->top());
1135 for (int i = 0; i < _class_promote_order->length(); i++) {
1136 oop obj = _class_promote_order->at(i);
1137 mark_and_move_ordered_ro.do_object(obj);
1138 }
1139 tty->print_cr("done. ");
1140 }
1141
1142 tty->print("Moving read-only objects to shared space at " PTR_FORMAT " ... ",
1143 _ro_space->top());
1144 gch->object_iterate(&mark_common_ro);
1145 gch->object_iterate(&move_ro);
1146 tty->print_cr("done. ");
1147
1148 // Phase 3: move String character arrays to the read-only space.
1149
1150 tty->print("Moving string char arrays to shared space at " PTR_FORMAT " ... ",
1151 _ro_space->top());
1152 gch->object_iterate(&mark_string_values);
1153 gch->object_iterate(&move_ro);
1154 tty->print_cr("done. ");
1155
1156 // Phase 4: move read-write objects to the read-write space, except
1157 // Strings.
1158
1159 if (SharedOptimizeColdStart) {
1160 tty->print("Moving pre-ordered read-write objects to shared space at " PTR_FORMAT " ... ",
1161 _rw_space->top());
1162 for (int i = 0; i < _class_promote_order->length(); i++) {
1163 oop obj = _class_promote_order->at(i);
1164 mark_and_move_ordered_rw.do_object(obj);
1165 }
1166 tty->print_cr("done. ");
1167 }
1168 tty->print("Moving read-write objects to shared space at " PTR_FORMAT " ... ",
1169 _rw_space->top());
1170 Universe::oops_do(&mark_all, true);
1171 SystemDictionary::oops_do(&mark_all);
1172 oop tmp = Universe::arithmetic_exception_instance();
1173 mark_object(java_lang_Throwable::message(tmp));
1174 gch->object_iterate(&mark_rw);
1175 gch->object_iterate(&move_rw);
1176 tty->print_cr("done. ");
1177
1178 // Phase 5: move String objects to the read-write space.
1179
1180 tty->print("Moving String objects to shared space at " PTR_FORMAT " ... ",
1181 _rw_space->top());
1182 StringTable::oops_do(&mark_all);
1183 gch->object_iterate(&mark_strings);
1184 gch->object_iterate(&move_rw);
1185 tty->print_cr("done. ");
1186 tty->print_cr("Read-write space ends at " PTR_FORMAT ", %d bytes.",
1187 _rw_space->top(), _rw_space->used());
1188
1189 #ifdef DEBUG
1190 // Check: scan for objects which were not moved.
1191
1192 CheckRemainingObjects check_objects;
1193 gch->object_iterate(&check_objects);
1194 check_objects.status();
1195 #endif
1196
1197 // Resolve forwarding in objects and saved C++ structures
1198 tty->print("Updating references to shared objects ... ");
1199 ResolveForwardingClosure resolve;
1200 Universe::oops_do(&resolve);
1201 SystemDictionary::oops_do(&resolve);
1202 StringTable::oops_do(&resolve);
1203
1204 // Fix (forward) all of the references in these shared objects (which
1205 // are required to point ONLY to objects in the shared spaces).
1206 // Also, create a list of all objects which might later contain a
1207 // reference to a younger generation object.
1208
1209 CompactingPermGenGen* gen = (CompactingPermGenGen*)gch->perm_gen();
1210 PatchOopsClosure patch(THREAD);
1211 gen->ro_space()->object_iterate(&patch);
1212 gen->rw_space()->object_iterate(&patch);
1213
1214 // Previously method sorting was done concurrently with forwarding
1215 // pointer resolution in the shared spaces. This imposed an ordering
1216 // restriction in that methods were required to be promoted/patched
1217 // before their holder classes. (Because constant pool pointers in
1218 // methodKlasses are required to be resolved before their holder class
1219 // is visited for sorting, otherwise methods are sorted by incorrect,
1220 // pre-forwarding addresses.)
1221 //
1222 // Now, we reorder methods as a separate step after ALL forwarding
1223 // pointer resolution, so that methods can be promoted in any order
1224 // with respect to their holder classes.
1225
1226 SortMethodsClosure sort;
1227 gen->ro_space()->object_iterate(&sort);
1228 gen->rw_space()->object_iterate(&sort);
1229
1230 ReinitializeTables reinit_tables(THREAD);
1231 gen->ro_space()->object_iterate(&reinit_tables);
1232 gen->rw_space()->object_iterate(&reinit_tables);
1233 tty->print_cr("done. ");
1234 tty->cr();
1235
1236 // Reorder the system dictionary. (Moving the symbols opps affects
1237 // how the hash table indices are calculated.)
1238
1239 SystemDictionary::reorder_dictionary();
1240
1241 // Empty the non-shared heap (because most of the objects were
1242 // copied out, and the remainder cannot be considered valid oops).
1243
1244 ClearSpaceClosure csc;
1245 for (int i = 0; i < gch->n_gens(); ++i) {
1246 gch->get_gen(i)->space_iterate(&csc);
1247 }
1248 csc.do_space(gen->the_space());
1249 NOT_PRODUCT(SystemDictionary::verify();)
1250
1251 // Copy the String table, the symbol table, and the system
1252 // dictionary to the shared space in usable form. Copy the hastable
1253 // buckets first [read-write], then copy the linked lists of entries
1254 // [read-only].
1255
1256 SymbolTable::reverse(extra_symbols);
1257 NOT_PRODUCT(SymbolTable::verify());
1258 SymbolTable::copy_buckets(&md_top, md_end);
1259
1260 StringTable::reverse();
1261 NOT_PRODUCT(StringTable::verify());
1262 StringTable::copy_buckets(&md_top, md_end);
1263
1264 SystemDictionary::reverse();
1265 SystemDictionary::copy_buckets(&md_top, md_end);
1266
1267 ClassLoader::verify();
1268 ClassLoader::copy_package_info_buckets(&md_top, md_end);
1269 ClassLoader::verify();
1270
1271 SymbolTable::copy_table(&md_top, md_end);
1272 StringTable::copy_table(&md_top, md_end);
1273 SystemDictionary::copy_table(&md_top, md_end);
1274 ClassLoader::verify();
1275 ClassLoader::copy_package_info_table(&md_top, md_end);
1276 ClassLoader::verify();
1277
1278 // Print debug data.
1279
1280 if (PrintSharedSpaces) {
1281 const char* fmt = "%s space: " PTR_FORMAT " out of " PTR_FORMAT " bytes allocated at " PTR_FORMAT ".";
1282 tty->print_cr(fmt, "ro", _ro_space->used(), _ro_space->capacity(),
1283 _ro_space->bottom());
1284 tty->print_cr(fmt, "rw", _rw_space->used(), _rw_space->capacity(),
1285 _rw_space->bottom());
1286 }
1287
1288 // Write the oop data to the output array.
1289
1290 WriteClosure wc(md_top, md_end);
1291 CompactingPermGenGen::serialize_oops(&wc);
1292 md_top = wc.get_top();
1293
1294 // Update the vtable pointers in all of the Klass objects in the
1295 // heap. They should point to newly generated vtable.
1296
1297 PatchKlassVtables pkvt;
1298 _rw_space->object_iterate(&pkvt);
1299 pkvt.patch(vtbl_list, vtable);
1300
1301 #ifndef PRODUCT
1302 // Update the vtable pointers in all symbols,
1303 // but only in non-product builds where symbols DO have virtual methods.
1304 PatchSymbolVtables psvt(vtbl_list, vtable);
1305 SymbolTable::symbols_do(&psvt);
1306 #endif
1307
1308 char* saved_vtbl = (char*)malloc(vtbl_list_size * sizeof(void*));
1309 memmove(saved_vtbl, vtbl_list, vtbl_list_size * sizeof(void*));
1310 memset(vtbl_list, 0, vtbl_list_size * sizeof(void*));
1311
1312 // Create and write the archive file that maps the shared spaces.
1313
1314 FileMapInfo* mapinfo = new FileMapInfo();
1315 mapinfo->populate_header(gch->gen_policy()->max_alignment());
1316
1317 // Pass 1 - update file offsets in header.
1318 mapinfo->write_header();
1319 mapinfo->write_space(CompactingPermGenGen::ro, _ro_space, true);
1320 _ro_space->set_saved_mark();
1321 mapinfo->write_space(CompactingPermGenGen::rw, _rw_space, false);
1322 _rw_space->set_saved_mark();
1323 mapinfo->write_region(CompactingPermGenGen::md, _md_vs->low(),
1324 pointer_delta(md_top, _md_vs->low(), sizeof(char)),
1325 SharedMiscDataSize,
1326 false, false);
1327 mapinfo->write_region(CompactingPermGenGen::mc, _mc_vs->low(),
1328 pointer_delta(mc_top, _mc_vs->low(), sizeof(char)),
1329 SharedMiscCodeSize,
1330 true, true);
1331
1332 // Pass 2 - write data.
1333 mapinfo->open_for_write();
1334 mapinfo->write_header();
1335 mapinfo->write_space(CompactingPermGenGen::ro, _ro_space, true);
1336 mapinfo->write_space(CompactingPermGenGen::rw, _rw_space, false);
1337 mapinfo->write_region(CompactingPermGenGen::md, _md_vs->low(),
1338 pointer_delta(md_top, _md_vs->low(), sizeof(char)),
1339 SharedMiscDataSize,
1340 false, false);
1341 mapinfo->write_region(CompactingPermGenGen::mc, _mc_vs->low(),
1342 pointer_delta(mc_top, _mc_vs->low(), sizeof(char)),
1343 SharedMiscCodeSize,
1344 true, true);
1345 mapinfo->close();
1346
1347 // Summarize heap.
1348 memmove(vtbl_list, saved_vtbl, vtbl_list_size * sizeof(void*));
1349 print_contents();
1350 }
1351 }; // class VM_PopulateDumpSharedSpace
1352
1353
1354 // Populate the shared spaces and dump to a file.
1355
1356 jint CompactingPermGenGen::dump_shared(GrowableArray<oop>* class_promote_order, TRAPS) {
1357 GenCollectedHeap* gch = GenCollectedHeap::heap();
1358
1359 // Calculate hash values for all of the (interned) strings to avoid
1360 // writes to shared pages in the future.
1361
1362 tty->print("Calculating hash values for String objects .. ");
1363 StringHashCodeClosure shcc(THREAD);
1364 StringTable::oops_do(&shcc);
1365 tty->print_cr("done. ");
1366
1367 CompactingPermGenGen* gen = (CompactingPermGenGen*)gch->perm_gen();
1368 VM_PopulateDumpSharedSpace op(class_promote_order,
1369 gen->ro_space(), gen->rw_space(),
1370 gen->md_space(), gen->mc_space());
1371 VMThread::execute(&op);
1372 return JNI_OK;
1373 }
1374
1375 void* CompactingPermGenGen::find_matching_vtbl_ptr(void** vtbl_list,
1376 void* new_vtable_start,
1377 void* obj) {
1378 void* old_vtbl_ptr = *(void**)obj;
1379 for (int i = 0; i < vtbl_list_size; i++) {
1380 if (vtbl_list[i] == old_vtbl_ptr) {
1381 return (void**)new_vtable_start + i * num_virtuals;
1382 }
1383 }
1384 ShouldNotReachHere();
1385 return NULL;
1386 }
1387
1388
1389 class LinkClassesClosure : public ObjectClosure {
1390 private:
1391 Thread* THREAD;
1392
1393 public:
1394 LinkClassesClosure(Thread* thread) : THREAD(thread) {}
1395
1396 void do_object(oop obj) {
1397 if (obj->is_klass()) {
1398 Klass* k = Klass::cast((klassOop) obj);
1399 if (k->oop_is_instance()) {
1400 instanceKlass* ik = (instanceKlass*) k;
1401 // Link the class to cause the bytecodes to be rewritten and the
1402 // cpcache to be created.
1403 if (ik->init_state() < instanceKlass::linked) {
1404 ik->link_class(THREAD);
1405 guarantee(!HAS_PENDING_EXCEPTION, "exception in class rewriting");
1406 }
1407
1408 // Create String objects from string initializer symbols.
1409 ik->constants()->resolve_string_constants(THREAD);
1410 guarantee(!HAS_PENDING_EXCEPTION, "exception resolving string constants");
1411 }
1412 }
1413 }
1414 };
1415
1416
1417 // Support for a simple checksum of the contents of the class list
1418 // file to prevent trivial tampering. The algorithm matches that in
1419 // the MakeClassList program used by the J2SE build process.
1420 #define JSUM_SEED ((jlong)CONST64(0xcafebabebabecafe))
1421 static jlong
1422 jsum(jlong start, const char *buf, const int len)
1423 {
1424 jlong h = start;
1425 char *p = (char *)buf, *e = p + len;
1426 while (p < e) {
1427 char c = *p++;
1428 if (c <= ' ') {
1429 /* Skip spaces and control characters */
1430 continue;
1431 }
1432 h = 31 * h + c;
1433 }
1434 return h;
1435 }
1436
1437
1438
1439
1440
1441 // Preload classes from a list, populate the shared spaces and dump to a
1442 // file.
1443
1444 void GenCollectedHeap::preload_and_dump(TRAPS) {
1445 TraceTime timer("Dump Shared Spaces", TraceStartupTime);
1446 ResourceMark rm;
1447
1448 // Preload classes to be shared.
1449 // Should use some os:: method rather than fopen() here. aB.
1450 // Construct the path to the class list (in jre/lib)
1451 // Walk up two directories from the location of the VM and
1452 // optionally tack on "lib" (depending on platform)
1453 char class_list_path[JVM_MAXPATHLEN];
1454 os::jvm_path(class_list_path, sizeof(class_list_path));
1455 for (int i = 0; i < 3; i++) {
1456 char *end = strrchr(class_list_path, *os::file_separator());
1457 if (end != NULL) *end = '\0';
1458 }
1459 int class_list_path_len = (int)strlen(class_list_path);
1460 if (class_list_path_len >= 3) {
1461 if (strcmp(class_list_path + class_list_path_len - 3, "lib") != 0) {
1462 strcat(class_list_path, os::file_separator());
1463 strcat(class_list_path, "lib");
1464 }
1465 }
1466 strcat(class_list_path, os::file_separator());
1467 strcat(class_list_path, "classlist");
1468
1469 FILE* file = fopen(class_list_path, "r");
1470 if (file != NULL) {
1471 jlong computed_jsum = JSUM_SEED;
1472 jlong file_jsum = 0;
1473
1474 char class_name[256];
1475 int class_count = 0;
1476 GenCollectedHeap* gch = GenCollectedHeap::heap();
1477 gch->_preloading_shared_classes = true;
1478 GrowableArray<oop>* class_promote_order = new GrowableArray<oop>();
1479
1480 // Preload (and intern) strings which will be used later.
1481
1482 StringTable::intern("main", THREAD);
1483 StringTable::intern("([Ljava/lang/String;)V", THREAD);
1484 StringTable::intern("Ljava/lang/Class;", THREAD);
1485
1486 StringTable::intern("I", THREAD); // Needed for StringBuffer persistence?
1487 StringTable::intern("Z", THREAD); // Needed for StringBuffer persistence?
1488
1489 // sun.io.Converters
1490 static const char obj_array_sig[] = "[[Ljava/lang/Object;";
1491 (void)SymbolTable::new_permanent_symbol(obj_array_sig, THREAD);
1492
1493 // java.util.HashMap
1494 static const char map_entry_array_sig[] = "[Ljava/util/Map$Entry;";
1495 (void)SymbolTable::new_permanent_symbol(map_entry_array_sig, THREAD);
1496
1497 tty->print("Loading classes to share ... ");
1498 while ((fgets(class_name, sizeof class_name, file)) != NULL) {
1499 if (*class_name == '#') {
1500 jint fsh, fsl;
1501 if (sscanf(class_name, "# %8x%8x\n", &fsh, &fsl) == 2) {
1502 file_jsum = ((jlong)(fsh) << 32) | (fsl & 0xffffffff);
1503 }
1504
1505 continue;
1506 }
1507 // Remove trailing newline
1508 size_t name_len = strlen(class_name);
1509 class_name[name_len-1] = '\0';
1510
1511 computed_jsum = jsum(computed_jsum, class_name, (const int)name_len - 1);
1512
1513 // Got a class name - load it.
1514 Symbol* class_name_symbol = SymbolTable::new_permanent_symbol(class_name, THREAD);
1515 guarantee(!HAS_PENDING_EXCEPTION, "Exception creating a symbol.");
1516 klassOop klass = SystemDictionary::resolve_or_null(class_name_symbol,
1517 THREAD);
1518 guarantee(!HAS_PENDING_EXCEPTION, "Exception resolving a class.");
1519 if (klass != NULL) {
1520 if (PrintSharedSpaces) {
1521 tty->print_cr("Shared spaces preloaded: %s", class_name);
1522 }
1523
1524
1525 instanceKlass* ik = instanceKlass::cast(klass);
1526
1527 // Should be class load order as per -XX:+TraceClassLoadingPreorder
1528 class_promote_order->append(ik->as_klassOop());
1529
1530 // Link the class to cause the bytecodes to be rewritten and the
1531 // cpcache to be created. The linking is done as soon as classes
1532 // are loaded in order that the related data structures (klass,
1533 // cpCache, Sting constants) are located together.
1534
1535 if (ik->init_state() < instanceKlass::linked) {
1536 ik->link_class(THREAD);
1537 guarantee(!(HAS_PENDING_EXCEPTION), "exception in class rewriting");
1538 }
1539
1540 // Create String objects from string initializer symbols.
1541
1542 ik->constants()->resolve_string_constants(THREAD);
1543
1544 class_count++;
1545 } else {
1546 if (PrintSharedSpaces) {
1547 tty->cr();
1548 tty->print_cr(" Preload failed: %s", class_name);
1549 }
1550 }
1551 file_jsum = 0; // Checksum must be on last line of file
1552 }
1553 if (computed_jsum != file_jsum) {
1554 tty->cr();
1555 tty->print_cr("Preload failed: checksum of class list was incorrect.");
1556 exit(1);
1557 }
1558
1559 tty->print_cr("done. ");
1560
1561 if (PrintSharedSpaces) {
1562 tty->print_cr("Shared spaces: preloaded %d classes", class_count);
1563 }
1564
1565 // Rewrite and unlink classes.
1566 tty->print("Rewriting and unlinking classes ... ");
1567 // Make heap parsable
1568 ensure_parsability(false); // arg is actually don't care
1569
1570 // Link any classes which got missed. (It's not quite clear why
1571 // they got missed.) This iteration would be unsafe if we weren't
1572 // single-threaded at this point; however we can't do it on the VM
1573 // thread because it requires object allocation.
1574 LinkClassesClosure lcc(Thread::current());
1575 object_iterate(&lcc);
1576 ensure_parsability(false); // arg is actually don't care
1577 tty->print_cr("done. ");
1578
1579 // Create and dump the shared spaces.
1580 jint err = CompactingPermGenGen::dump_shared(class_promote_order, THREAD);
1581 if (err != JNI_OK) {
1582 fatal("Dumping shared spaces failed.");
1583 }
1584
1585 } else {
1586 char errmsg[JVM_MAXPATHLEN];
1587 os::lasterror(errmsg, JVM_MAXPATHLEN);
1588 tty->print_cr("Loading classlist failed: %s", errmsg);
1589 exit(1);
1590 }
1591
1592 // Since various initialization steps have been undone by this process,
1593 // it is not reasonable to continue running a java process.
1594 exit(0);
1595 }