1 /*
2 * Copyright (c) 2003, 2011, 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 typeArrayOop inner_classes = ik->inner_classes();
301 if (inner_classes != NULL) {
302 constantPoolOop constants = ik->constants();
303 int n = inner_classes->length();
304 for (int i = 0; i < n; i += instanceKlass::inner_class_next_offset) {
305 int ioff = i + instanceKlass::inner_class_inner_name_offset;
306 int index = inner_classes->ushort_at(ioff);
307 if (index != 0) {
308 _closure->do_symbol(constants->symbol_at_addr(index));
309 }
310 }
311 }
312 }
313 }
314
315 // Traverse symbols referenced by other constantpool entries.
316
317 else if (obj->is_constantPool()) {
318 constantPoolOop(obj)->shared_symbols_iterate(_closure);
319 }
320 }
321 };
322
323
324 // Closure: mark char arrays used by strings
325
326 class MarkStringValues : public ObjectClosure {
327 private:
328 MarkObjectsOopClosure mark_all;
329 public:
330 void do_object(oop obj) {
331
332 // Character arrays referenced by String objects are read-only.
333
334 if (java_lang_String::is_instance(obj)) {
335 mark_object(java_lang_String::value(obj));
336 }
337 }
338 };
339
340
341 #ifdef DEBUG
342 // Closure: Check for objects left in the heap which have not been moved.
343
344 class CheckRemainingObjects : public ObjectClosure {
345 private:
346 int count;
347
348 public:
349 CheckRemainingObjects() {
350 count = 0;
351 }
352
353 void do_object(oop obj) {
354 if (!obj->is_shared() &&
355 !obj->is_forwarded()) {
356 ++count;
357 if (Verbose) {
358 tty->print("Unreferenced object: ");
359 obj->print_on(tty);
360 }
361 }
362 }
363
364 void status() {
365 tty->print_cr("%d objects no longer referenced, not shared.", count);
366 }
367 };
368 #endif
369
370
371 // Closure: Mark remaining objects read-write, except Strings.
372
373 class MarkReadWriteObjects : public ObjectClosure {
374 private:
375 MarkObjectsOopClosure mark_objects;
376 public:
377 void do_object(oop obj) {
378
379 // The METHODS() OBJARRAYS CANNOT BE MADE READ-ONLY, even though
380 // it is never modified. Otherwise, they will be pre-marked; the
381 // GC marking phase will skip them; and by skipping them will fail
382 // to mark the methods objects referenced by the array.
383
384 if (obj->is_klass()) {
385 mark_object(obj);
386 Klass* k = klassOop(obj)->klass_part();
387 mark_object(k->java_mirror());
388 if (obj->blueprint()->oop_is_instanceKlass()) {
389 instanceKlass* ik = (instanceKlass*)k;
390 mark_object(ik->methods());
391 mark_object(ik->constants());
392 }
393 if (obj->blueprint()->oop_is_javaArray()) {
394 arrayKlass* ak = (arrayKlass*)k;
395 mark_object(ak->component_mirror());
396 }
397 return;
398 }
399
400 // Mark constantPool tags and the constantPoolCache.
401
402 else if (obj->is_constantPool()) {
403 constantPoolOop pool = constantPoolOop(obj);
404 mark_object(pool->cache());
405 pool->shared_tags_iterate(&mark_objects);
406 return;
407 }
408
409 // Mark all method objects.
410
411 if (obj->is_method()) {
412 mark_object(obj);
413 }
414 }
415 };
416
417
418 // Closure: Mark String objects read-write.
419
420 class MarkStringObjects : public ObjectClosure {
421 private:
422 MarkObjectsOopClosure mark_objects;
423 public:
424 void do_object(oop obj) {
425
426 // Mark String objects referenced by constant pool entries.
427
428 if (obj->is_constantPool()) {
429 constantPoolOop pool = constantPoolOop(obj);
430 pool->shared_strings_iterate(&mark_objects);
431 return;
432 }
433 }
434 };
435
436
437 // Move objects matching specified type (ie. lock_bits) to the specified
438 // space.
439
440 class MoveMarkedObjects : public ObjectClosure {
441 private:
442 OffsetTableContigSpace* _space;
443 bool _read_only;
444
445 public:
446 MoveMarkedObjects(OffsetTableContigSpace* space, bool read_only) {
447 _space = space;
448 _read_only = read_only;
449 }
450
451 void do_object(oop obj) {
452 if (obj->is_shared()) {
453 return;
454 }
455 if (obj->is_gc_marked() && obj->forwardee() == NULL) {
456 int s = obj->size();
457 oop sh_obj = (oop)_space->allocate(s);
458 if (sh_obj == NULL) {
459 report_out_of_shared_space(_read_only ? SharedReadOnly : SharedReadWrite);
460 }
461 if (PrintSharedSpaces && Verbose && WizardMode) {
462 tty->print_cr("\nMoveMarkedObjects: " PTR_FORMAT " -> " PTR_FORMAT " %s", obj, sh_obj,
463 (_read_only ? "ro" : "rw"));
464 }
465 Copy::aligned_disjoint_words((HeapWord*)obj, (HeapWord*)sh_obj, s);
466 obj->forward_to(sh_obj);
467 if (_read_only) {
468 // Readonly objects: set hash value to self pointer and make gc_marked.
469 sh_obj->forward_to(sh_obj);
470 } else {
471 sh_obj->init_mark();
472 }
473 }
474 }
475 };
476
477 static void mark_and_move(oop obj, MoveMarkedObjects* move) {
478 if (mark_object(obj)) move->do_object(obj);
479 }
480
481 enum order_policy {
482 OP_favor_startup = 0,
483 OP_balanced = 1,
484 OP_favor_runtime = 2
485 };
486
487 static void mark_and_move_for_policy(order_policy policy, oop obj, MoveMarkedObjects* move) {
488 if (SharedOptimizeColdStartPolicy >= policy) mark_and_move(obj, move);
489 }
490
491 class MarkAndMoveOrderedReadOnly : public ObjectClosure {
492 private:
493 MoveMarkedObjects *_move_ro;
494
495 public:
496 MarkAndMoveOrderedReadOnly(MoveMarkedObjects *move_ro) : _move_ro(move_ro) {}
497
498 void do_object(oop obj) {
499 if (obj->is_klass() && obj->blueprint()->oop_is_instanceKlass()) {
500 instanceKlass* ik = instanceKlass::cast((klassOop)obj);
501 int i;
502
503 if (ik->super() != NULL) {
504 do_object(ik->super());
505 }
506
507 objArrayOop interfaces = ik->local_interfaces();
508 mark_and_move_for_policy(OP_favor_startup, interfaces, _move_ro);
509 for(i = 0; i < interfaces->length(); i++) {
510 klassOop k = klassOop(interfaces->obj_at(i));
511 do_object(k);
512 }
513
514 objArrayOop methods = ik->methods();
515 for(i = 0; i < methods->length(); i++) {
516 methodOop m = methodOop(methods->obj_at(i));
517 mark_and_move_for_policy(OP_favor_startup, m->constMethod(), _move_ro);
518 mark_and_move_for_policy(OP_favor_runtime, m->constMethod()->exception_table(), _move_ro);
519 mark_and_move_for_policy(OP_favor_runtime, m->constMethod()->stackmap_data(), _move_ro);
520 }
521
522 mark_and_move_for_policy(OP_favor_startup, ik->transitive_interfaces(), _move_ro);
523 mark_and_move_for_policy(OP_favor_startup, ik->fields(), _move_ro);
524
525 mark_and_move_for_policy(OP_favor_runtime, ik->secondary_supers(), _move_ro);
526 mark_and_move_for_policy(OP_favor_runtime, ik->method_ordering(), _move_ro);
527 mark_and_move_for_policy(OP_favor_runtime, ik->class_annotations(), _move_ro);
528 mark_and_move_for_policy(OP_favor_runtime, ik->fields_annotations(), _move_ro);
529 mark_and_move_for_policy(OP_favor_runtime, ik->methods_annotations(), _move_ro);
530 mark_and_move_for_policy(OP_favor_runtime, ik->methods_parameter_annotations(), _move_ro);
531 mark_and_move_for_policy(OP_favor_runtime, ik->methods_default_annotations(), _move_ro);
532 mark_and_move_for_policy(OP_favor_runtime, ik->inner_classes(), _move_ro);
533 mark_and_move_for_policy(OP_favor_runtime, ik->secondary_supers(), _move_ro);
534 }
535 }
536 };
537
538 class MarkAndMoveOrderedReadWrite: public ObjectClosure {
539 private:
540 MoveMarkedObjects *_move_rw;
541
542 public:
543 MarkAndMoveOrderedReadWrite(MoveMarkedObjects *move_rw) : _move_rw(move_rw) {}
544
545 void do_object(oop obj) {
546 if (obj->is_klass() && obj->blueprint()->oop_is_instanceKlass()) {
547 instanceKlass* ik = instanceKlass::cast((klassOop)obj);
548 int i;
549
550 mark_and_move_for_policy(OP_favor_startup, ik->as_klassOop(), _move_rw);
551
552 if (ik->super() != NULL) {
553 do_object(ik->super());
554 }
555
556 objArrayOop interfaces = ik->local_interfaces();
557 for(i = 0; i < interfaces->length(); i++) {
558 klassOop k = klassOop(interfaces->obj_at(i));
559 mark_and_move_for_policy(OP_favor_startup, k, _move_rw);
560 do_object(k);
561 }
562
563 objArrayOop methods = ik->methods();
564 mark_and_move_for_policy(OP_favor_startup, methods, _move_rw);
565 for(i = 0; i < methods->length(); i++) {
566 methodOop m = methodOop(methods->obj_at(i));
567 mark_and_move_for_policy(OP_favor_startup, m, _move_rw);
568 mark_and_move_for_policy(OP_favor_startup, ik->constants(), _move_rw); // idempotent
569 mark_and_move_for_policy(OP_balanced, ik->constants()->cache(), _move_rw); // idempotent
570 mark_and_move_for_policy(OP_balanced, ik->constants()->tags(), _move_rw); // idempotent
571 }
572
573 mark_and_move_for_policy(OP_favor_startup, ik->as_klassOop()->klass(), _move_rw);
574 mark_and_move_for_policy(OP_favor_startup, ik->constants()->klass(), _move_rw);
575
576 // Although Java mirrors are marked in MarkReadWriteObjects,
577 // apparently they were never moved into shared spaces since
578 // MoveMarkedObjects skips marked instance oops. This may
579 // be a bug in the original implementation or simply the vestige
580 // of an abandoned experiment. Nevertheless we leave a hint
581 // here in case this capability is ever correctly implemented.
582 //
583 // mark_and_move_for_policy(OP_favor_runtime, ik->java_mirror(), _move_rw);
584 }
585 }
586
587 };
588
589 // Adjust references in oops to refer to shared spaces.
590
591 class ResolveForwardingClosure: public OopClosure {
592 public:
593 void do_oop(oop* p) {
594 oop obj = *p;
595 if (!obj->is_shared()) {
596 if (obj != NULL) {
597 oop f = obj->forwardee();
598 guarantee(f->is_shared(), "Oop doesn't refer to shared space.");
599 *p = f;
600 }
601 }
602 }
603 void do_oop(narrowOop* pobj) { ShouldNotReachHere(); }
604 };
605
606
607 // The methods array must be reordered by Symbol* address.
608 // (See classFileParser.cpp where methods in a class are originally
609 // sorted). The addresses of symbols have been changed as a result
610 // of moving to the shared space.
611
612 class SortMethodsClosure: public ObjectClosure {
613 public:
614 void do_object(oop obj) {
615 if (obj->blueprint()->oop_is_instanceKlass()) {
616 instanceKlass* ik = instanceKlass::cast((klassOop)obj);
617 methodOopDesc::sort_methods(ik->methods(),
618 ik->methods_annotations(),
619 ik->methods_parameter_annotations(),
620 ik->methods_default_annotations(),
621 true /* idempotent, slow */);
622 }
623 }
624 };
625
626 // Vtable and Itable indices are calculated based on methods array
627 // order (see klassItable::compute_itable_index()). Must reinitialize
628 // after ALL methods of ALL classes have been reordered.
629 // We assume that since checkconstraints is false, this method
630 // cannot throw an exception. An exception here would be
631 // problematic since this is the VMThread, not a JavaThread.
632
633 class ReinitializeTables: public ObjectClosure {
634 private:
635 Thread* _thread;
636
637 public:
638 ReinitializeTables(Thread* thread) : _thread(thread) {}
639
640 // Initialize super vtable first, check if already initialized to avoid
641 // quadradic behavior. The vtable is cleared in remove_unshareable_info.
642 void reinitialize_vtables(klassOop k) {
643 if (k->blueprint()->oop_is_instanceKlass()) {
644 instanceKlass* ik = instanceKlass::cast(k);
645 if (ik->vtable()->is_initialized()) return;
646 if (ik->super() != NULL) {
647 reinitialize_vtables(ik->super());
648 }
649 ik->vtable()->initialize_vtable(false, _thread);
650 }
651 }
652
653 void do_object(oop obj) {
654 if (obj->blueprint()->oop_is_instanceKlass()) {
655 instanceKlass* ik = instanceKlass::cast((klassOop)obj);
656 ResourceMark rm(_thread);
657 ik->itable()->initialize_itable(false, _thread);
658 reinitialize_vtables((klassOop)obj);
659 #ifdef ASSERT
660 ik->vtable()->verify(tty, true);
661 #endif // ASSERT
662 } else if (obj->blueprint()->oop_is_arrayKlass()) {
663 // The vtable for array klasses are that of its super class,
664 // ie. java.lang.Object.
665 arrayKlass* ak = arrayKlass::cast((klassOop)obj);
666 if (ak->vtable()->is_initialized()) return;
667 ak->vtable()->initialize_vtable(false, _thread);
668 }
669 }
670 };
671
672
673 // Adjust references in oops to refer to shared spaces.
674
675 class PatchOopsClosure: public ObjectClosure {
676 private:
677 Thread* _thread;
678 ResolveForwardingClosure resolve;
679
680 public:
681 PatchOopsClosure(Thread* thread) : _thread(thread) {}
682
683 void do_object(oop obj) {
684 obj->oop_iterate_header(&resolve);
685 obj->oop_iterate(&resolve);
686
687 assert(obj->klass()->is_shared(), "Klass not pointing into shared space.");
688
689 // If the object is a Java object or class which might (in the
690 // future) contain a reference to a young gen object, add it to the
691 // list.
692
693 if (obj->is_klass() || obj->is_instance()) {
694 if (obj->is_klass() ||
695 obj->is_a(SystemDictionary::Class_klass()) ||
696 obj->is_a(SystemDictionary::Throwable_klass())) {
697 // Do nothing
698 }
699 else if (obj->is_a(SystemDictionary::String_klass())) {
700 // immutable objects.
701 } else {
702 // someone added an object we hadn't accounted for.
703 ShouldNotReachHere();
704 }
705 }
706 }
707 };
708
709
710 // Empty the young and old generations.
711
712 class ClearSpaceClosure : public SpaceClosure {
713 public:
714 void do_space(Space* s) {
715 s->clear(SpaceDecorator::Mangle);
716 }
717 };
718
719
720 // Closure for serializing initialization data out to a data area to be
721 // written to the shared file.
722
723 class WriteClosure : public SerializeOopClosure {
724 private:
725 oop* top;
726 char* end;
727
728 inline void check_space() {
729 if ((char*)top + sizeof(oop) > end) {
730 report_out_of_shared_space(SharedMiscData);
731 }
732 }
733
734
735 public:
736 WriteClosure(char* md_top, char* md_end) {
737 top = (oop*)md_top;
738 end = md_end;
739 }
740
741 char* get_top() { return (char*)top; }
742
743 void do_oop(oop* p) {
744 check_space();
745 oop obj = *p;
746 assert(obj->is_oop_or_null(), "invalid oop");
747 assert(obj == NULL || obj->is_shared(),
748 "Oop in shared space not pointing into shared space.");
749 *top = obj;
750 ++top;
751 }
752
753 void do_oop(narrowOop* pobj) { ShouldNotReachHere(); }
754
755 void do_int(int* p) {
756 check_space();
757 *top = (oop)(intptr_t)*p;
758 ++top;
759 }
760
761 void do_size_t(size_t* p) {
762 check_space();
763 *top = (oop)(intptr_t)*p;
764 ++top;
765 }
766
767 void do_ptr(void** p) {
768 check_space();
769 *top = (oop)*p;
770 ++top;
771 }
772
773 void do_ptr(HeapWord** p) { do_ptr((void **) p); }
774
775 void do_tag(int tag) {
776 check_space();
777 *top = (oop)(intptr_t)tag;
778 ++top;
779 }
780
781 void do_region(u_char* start, size_t size) {
782 if ((char*)top + size > end) {
783 report_out_of_shared_space(SharedMiscData);
784 }
785 assert((intptr_t)start % sizeof(oop) == 0, "bad alignment");
786 assert(size % sizeof(oop) == 0, "bad size");
787 do_tag((int)size);
788 while (size > 0) {
789 *top = *(oop*)start;
790 ++top;
791 start += sizeof(oop);
792 size -= sizeof(oop);
793 }
794 }
795
796 bool reading() const { return false; }
797 };
798
799
800 class ResolveConstantPoolsClosure : public ObjectClosure {
801 private:
802 TRAPS;
803 public:
804 ResolveConstantPoolsClosure(Thread *t) {
805 __the_thread__ = t;
806 }
807 void do_object(oop obj) {
808 if (obj->is_constantPool()) {
809 constantPoolOop cpool = (constantPoolOop)obj;
810 int unresolved = cpool->pre_resolve_shared_klasses(THREAD);
811 }
812 }
813 };
814
815
816 // Print a summary of the contents of the read/write spaces to help
817 // identify objects which might be able to be made read-only. At this
818 // point, the objects have been written, and we can trash them as
819 // needed.
820
821 static void print_contents() {
822 if (PrintSharedSpaces) {
823 GenCollectedHeap* gch = GenCollectedHeap::heap();
824 CompactingPermGenGen* gen = (CompactingPermGenGen*)gch->perm_gen();
825
826 // High level summary of the read-only space:
827
828 ClassifyObjectClosure coc;
829 tty->cr(); tty->print_cr("ReadOnly space:");
830 gen->ro_space()->object_iterate(&coc);
831 coc.print();
832
833 // High level summary of the read-write space:
834
835 coc.reset();
836 tty->cr(); tty->print_cr("ReadWrite space:");
837 gen->rw_space()->object_iterate(&coc);
838 coc.print();
839
840 // Reset counters
841
842 ClearAllocCountClosure cacc;
843 gen->ro_space()->object_iterate(&cacc);
844 gen->rw_space()->object_iterate(&cacc);
845 coc.reset();
846
847 // Lower level summary of the read-only space:
848
849 gen->ro_space()->object_iterate(&coc);
850 tty->cr(); tty->print_cr("ReadOnly space:");
851 ClassifyInstanceKlassClosure cikc;
852 gen->rw_space()->object_iterate(&cikc);
853 cikc.print();
854
855 // Reset counters
856
857 gen->ro_space()->object_iterate(&cacc);
858 gen->rw_space()->object_iterate(&cacc);
859 coc.reset();
860
861 // Lower level summary of the read-write space:
862
863 gen->rw_space()->object_iterate(&coc);
864 cikc.reset();
865 tty->cr(); tty->print_cr("ReadWrite space:");
866 gen->rw_space()->object_iterate(&cikc);
867 cikc.print();
868 }
869 }
870
871
872 // Patch C++ vtable pointer in klass oops.
873
874 // Klass objects contain references to c++ vtables in the JVM library.
875 // Fix them to point to our constructed vtables. However, don't iterate
876 // across the space while doing this, as that causes the vtables to be
877 // patched, undoing our useful work. Instead, iterate to make a list,
878 // then use the list to do the fixing.
879 //
880 // Our constructed vtables:
881 // Dump time:
882 // 1. init_self_patching_vtbl_list: table of pointers to current virtual method addrs
883 // 2. generate_vtable_methods: create jump table, appended to above vtbl_list
884 // 3. PatchKlassVtables: for Klass list, patch the vtable entry to point to jump table
885 // rather than to current vtbl
886 // Table layout: NOTE FIXED SIZE
887 // 1. vtbl pointers
888 // 2. #Klass X #virtual methods per Klass
889 // 1 entry for each, in the order:
890 // Klass1:method1 entry, Klass1:method2 entry, ... Klass1:method<num_virtuals> entry
891 // Klass2:method1 entry, Klass2:method2 entry, ... Klass2:method<num_virtuals> entry
892 // ...
893 // Klass<vtbl_list_size>:method1 entry, Klass<vtbl_list_size>:method2 entry,
894 // ... Klass<vtbl_list_size>:method<num_virtuals> entry
895 // Sample entry: (Sparc):
896 // save(sp, -256, sp)
897 // ba,pt common_code
898 // mov XXX, %L0 %L0 gets: Klass index <<8 + method index (note: max method index 255)
899 //
900 // Restore time:
901 // 1. initialize_oops: reserve space for table
902 // 2. init_self_patching_vtbl_list: update pointers to NEW virtual method addrs in text
903 //
904 // Execution time:
905 // First virtual method call for any object of these Klass types:
906 // 1. object->klass->klass_part
907 // 2. vtable entry for that klass_part points to the jump table entries
908 // 3. branches to common_code with %O0/klass_part, %L0: Klass index <<8 + method index
909 // 4. common_code:
910 // Get address of new vtbl pointer for this Klass from updated table
911 // Update new vtbl pointer in the Klass: future virtual calls go direct
912 // Jump to method, using new vtbl pointer and method index
913
914 class PatchKlassVtables: public ObjectClosure {
915 private:
916 GrowableArray<klassOop>* _klass_objects;
917
918 public:
919 PatchKlassVtables() {
920 _klass_objects = new GrowableArray<klassOop>();
921 }
922
923 void do_object(oop obj) {
924 if (obj->is_klass()) {
925 _klass_objects->append(klassOop(obj));
926 }
927 }
928
929 void patch(void** vtbl_list, void* new_vtable_start) {
930 int n = _klass_objects->length();
931 for (int i = 0; i < n; i++) {
932 klassOop obj = (klassOop)_klass_objects->at(i);
933 Klass* k = obj->klass_part();
934 *(void**)k = CompactingPermGenGen::find_matching_vtbl_ptr(
935 vtbl_list, new_vtable_start, k);
936 }
937 }
938 };
939
940 // Walk through all symbols and patch their vtable pointers.
941 // Note that symbols have vtable pointers only in non-product builds
942 // (see allocation.hpp).
943
944 #ifndef PRODUCT
945 class PatchSymbolVtables: public SymbolClosure {
946 private:
947 void* _new_vtbl_ptr;
948
949 public:
950 PatchSymbolVtables(void** vtbl_list, void* new_vtable_start) {
951 Symbol s;
952 _new_vtbl_ptr = CompactingPermGenGen::find_matching_vtbl_ptr(
953 vtbl_list, new_vtable_start, &s);
954 }
955
956 void do_symbol(Symbol** p) {
957 Symbol* sym = load_symbol(p);
958 *(void**)sym = _new_vtbl_ptr;
959 }
960 };
961 #endif
962
963
964 // Populate the shared space.
965
966 class VM_PopulateDumpSharedSpace: public VM_Operation {
967 private:
968 GrowableArray<oop> *_class_promote_order;
969 OffsetTableContigSpace* _ro_space;
970 OffsetTableContigSpace* _rw_space;
971 VirtualSpace* _md_vs;
972 VirtualSpace* _mc_vs;
973
974 public:
975 VM_PopulateDumpSharedSpace(GrowableArray<oop> *class_promote_order,
976 OffsetTableContigSpace* ro_space,
977 OffsetTableContigSpace* rw_space,
978 VirtualSpace* md_vs, VirtualSpace* mc_vs) {
979 _class_promote_order = class_promote_order;
980 _ro_space = ro_space;
981 _rw_space = rw_space;
982 _md_vs = md_vs;
983 _mc_vs = mc_vs;
984 }
985
986 VMOp_Type type() const { return VMOp_PopulateDumpSharedSpace; }
987 void doit() {
988 Thread* THREAD = VMThread::vm_thread();
989 NOT_PRODUCT(SystemDictionary::verify();)
990 // The following guarantee is meant to ensure that no loader constraints
991 // exist yet, since the constraints table is not shared. This becomes
992 // more important now that we don't re-initialize vtables/itables for
993 // shared classes at runtime, where constraints were previously created.
994 guarantee(SystemDictionary::constraints()->number_of_entries() == 0,
995 "loader constraints are not saved");
996 // Revisit and implement this if we prelink method handle call sites:
997 guarantee(SystemDictionary::invoke_method_table() == NULL ||
998 SystemDictionary::invoke_method_table()->number_of_entries() == 0,
999 "invoke method table is not saved");
1000 GenCollectedHeap* gch = GenCollectedHeap::heap();
1001
1002 // At this point, many classes have been loaded.
1003
1004 // Update all the fingerprints in the shared methods.
1005
1006 tty->print("Calculating fingerprints ... ");
1007 FingerprintMethodsClosure fpmc;
1008 gch->object_iterate(&fpmc);
1009 tty->print_cr("done. ");
1010
1011 // Remove all references outside the heap.
1012
1013 tty->print("Removing unshareable information ... ");
1014 RemoveUnshareableInfoClosure ruic;
1015 gch->object_iterate(&ruic);
1016 tty->print_cr("done. ");
1017
1018 // Move the objects in three passes.
1019
1020 MarkObjectsOopClosure mark_all;
1021 MarkCommonReadOnly mark_common_ro;
1022 MarkStringValues mark_string_values;
1023 MarkReadWriteObjects mark_rw;
1024 MarkStringObjects mark_strings;
1025 MoveMarkedObjects move_ro(_ro_space, true);
1026 MoveMarkedObjects move_rw(_rw_space, false);
1027
1028 // The SharedOptimizeColdStart VM option governs the new layout
1029 // algorithm for promoting classes into the shared archive.
1030 // The general idea is to minimize cold start time by laying
1031 // out the objects in the order they are accessed at startup time.
1032 // By doing this we are trying to eliminate out-of-order accesses
1033 // in the shared archive. This benefits cold startup time by making
1034 // disk reads as sequential as possible during class loading and
1035 // bootstrapping activities. There may also be a small secondary
1036 // effect of better "packing" of more commonly used data on a smaller
1037 // number of pages, although no direct benefit has been measured from
1038 // this effect.
1039 //
1040 // At the class level of granularity, the promotion order is dictated
1041 // by the classlist file whose generation is discussed elsewhere.
1042 //
1043 // At smaller granularity, optimal ordering was determined by an
1044 // offline analysis of object access order in the shared archive.
1045 // The dbx watchpoint facility, combined with SA post-processing,
1046 // was used to observe common access patterns primarily during
1047 // classloading. This information was used to craft the promotion
1048 // order seen in the following closures.
1049 //
1050 // The observed access order is mostly governed by what happens
1051 // in SystemDictionary::load_shared_class(). NOTE WELL - care
1052 // should be taken when making changes to this method, because it
1053 // may invalidate assumptions made about access order!
1054 //
1055 // (Ideally, there would be a better way to manage changes to
1056 // the access order. Unfortunately a generic in-VM solution for
1057 // dynamically observing access order and optimizing shared
1058 // archive layout is pretty difficult. We go with the static
1059 // analysis because the code is fairly mature at this point
1060 // and we're betting that the access order won't change much.)
1061
1062 MarkAndMoveOrderedReadOnly mark_and_move_ordered_ro(&move_ro);
1063 MarkAndMoveOrderedReadWrite mark_and_move_ordered_rw(&move_rw);
1064
1065 // Set up the share data and shared code segments.
1066
1067 char* md_top = _md_vs->low();
1068 char* md_end = _md_vs->high();
1069 char* mc_top = _mc_vs->low();
1070 char* mc_end = _mc_vs->high();
1071
1072 // Reserve space for the list of klassOops whose vtables are used
1073 // for patching others as needed.
1074
1075 void** vtbl_list = (void**)md_top;
1076 int vtbl_list_size = CompactingPermGenGen::vtbl_list_size;
1077 Universe::init_self_patching_vtbl_list(vtbl_list, vtbl_list_size);
1078
1079 md_top += vtbl_list_size * sizeof(void*);
1080 void* vtable = md_top;
1081
1082 // Reserve space for a new dummy vtable for klass objects in the
1083 // heap. Generate self-patching vtable entries.
1084
1085 CompactingPermGenGen::generate_vtable_methods(vtbl_list,
1086 &vtable,
1087 &md_top, md_end,
1088 &mc_top, mc_end);
1089
1090 // Reserve space for the total size and the number of stored symbols.
1091
1092 md_top += sizeof(intptr_t) * 2;
1093
1094 MoveSymbols move_symbols(md_top, md_end);
1095 CommonSymbolsClosure traverse_common_symbols(&move_symbols);
1096
1097 // Phase 1a: remove symbols with _refcount == 0
1098
1099 SymbolTable::unlink();
1100
1101 // Phase 1b: move commonly used symbols referenced by oop fields.
1102
1103 tty->print("Moving common symbols to metadata section at " PTR_FORMAT " ... ",
1104 move_symbols.get_top());
1105 gch->object_iterate(&traverse_common_symbols);
1106 tty->print_cr("done. ");
1107
1108 // Phase 1c: move known names and signatures.
1109
1110 tty->print("Moving vmSymbols to metadata section at " PTR_FORMAT " ... ",
1111 move_symbols.get_top());
1112 vmSymbols::symbols_do(&move_symbols);
1113 tty->print_cr("done. ");
1114
1115 // Phase 1d: move the remaining symbols by scanning the whole SymbolTable.
1116
1117 void* extra_symbols = move_symbols.get_top();
1118 tty->print("Moving the remaining symbols to metadata section at " PTR_FORMAT " ... ",
1119 move_symbols.get_top());
1120 SymbolTable::symbols_do(&move_symbols);
1121 tty->print_cr("done. ");
1122
1123 // Record the total length of all symbols at the beginning of the block.
1124 ((intptr_t*)md_top)[-2] = move_symbols.get_top() - md_top;
1125 ((intptr_t*)md_top)[-1] = move_symbols.count();
1126 tty->print_cr("Moved %d symbols, %d bytes.",
1127 move_symbols.count(), move_symbols.get_top() - md_top);
1128 // Advance the pointer to the end of symbol store.
1129 md_top = move_symbols.get_top();
1130
1131
1132 // Phase 2: move commonly used read-only objects to the read-only space.
1133
1134 if (SharedOptimizeColdStart) {
1135 tty->print("Moving pre-ordered read-only objects to shared space at " PTR_FORMAT " ... ",
1136 _ro_space->top());
1137 for (int i = 0; i < _class_promote_order->length(); i++) {
1138 oop obj = _class_promote_order->at(i);
1139 mark_and_move_ordered_ro.do_object(obj);
1140 }
1141 tty->print_cr("done. ");
1142 }
1143
1144 tty->print("Moving read-only objects to shared space at " PTR_FORMAT " ... ",
1145 _ro_space->top());
1146 gch->object_iterate(&mark_common_ro);
1147 gch->object_iterate(&move_ro);
1148 tty->print_cr("done. ");
1149
1150 // Phase 3: move String character arrays to the read-only space.
1151
1152 tty->print("Moving string char arrays to shared space at " PTR_FORMAT " ... ",
1153 _ro_space->top());
1154 gch->object_iterate(&mark_string_values);
1155 gch->object_iterate(&move_ro);
1156 tty->print_cr("done. ");
1157
1158 // Phase 4: move read-write objects to the read-write space, except
1159 // Strings.
1160
1161 if (SharedOptimizeColdStart) {
1162 tty->print("Moving pre-ordered read-write objects to shared space at " PTR_FORMAT " ... ",
1163 _rw_space->top());
1164 for (int i = 0; i < _class_promote_order->length(); i++) {
1165 oop obj = _class_promote_order->at(i);
1166 mark_and_move_ordered_rw.do_object(obj);
1167 }
1168 tty->print_cr("done. ");
1169 }
1170 tty->print("Moving read-write objects to shared space at " PTR_FORMAT " ... ",
1171 _rw_space->top());
1172 Universe::oops_do(&mark_all, true);
1173 SystemDictionary::oops_do(&mark_all);
1174 oop tmp = Universe::arithmetic_exception_instance();
1175 mark_object(java_lang_Throwable::message(tmp));
1176 gch->object_iterate(&mark_rw);
1177 gch->object_iterate(&move_rw);
1178 tty->print_cr("done. ");
1179
1180 // Phase 5: move String objects to the read-write space.
1181
1182 tty->print("Moving String objects to shared space at " PTR_FORMAT " ... ",
1183 _rw_space->top());
1184 StringTable::oops_do(&mark_all);
1185 gch->object_iterate(&mark_strings);
1186 gch->object_iterate(&move_rw);
1187 tty->print_cr("done. ");
1188 tty->print_cr("Read-write space ends at " PTR_FORMAT ", %d bytes.",
1189 _rw_space->top(), _rw_space->used());
1190
1191 #ifdef DEBUG
1192 // Check: scan for objects which were not moved.
1193
1194 CheckRemainingObjects check_objects;
1195 gch->object_iterate(&check_objects);
1196 check_objects.status();
1197 #endif
1198
1199 // Resolve forwarding in objects and saved C++ structures
1200 tty->print("Updating references to shared objects ... ");
1201 ResolveForwardingClosure resolve;
1202 Universe::oops_do(&resolve);
1203 SystemDictionary::oops_do(&resolve);
1204 StringTable::oops_do(&resolve);
1205
1206 // Fix (forward) all of the references in these shared objects (which
1207 // are required to point ONLY to objects in the shared spaces).
1208 // Also, create a list of all objects which might later contain a
1209 // reference to a younger generation object.
1210
1211 CompactingPermGenGen* gen = (CompactingPermGenGen*)gch->perm_gen();
1212 PatchOopsClosure patch(THREAD);
1213 gen->ro_space()->object_iterate(&patch);
1214 gen->rw_space()->object_iterate(&patch);
1215
1216 // Previously method sorting was done concurrently with forwarding
1217 // pointer resolution in the shared spaces. This imposed an ordering
1218 // restriction in that methods were required to be promoted/patched
1219 // before their holder classes. (Because constant pool pointers in
1220 // methodKlasses are required to be resolved before their holder class
1221 // is visited for sorting, otherwise methods are sorted by incorrect,
1222 // pre-forwarding addresses.)
1223 //
1224 // Now, we reorder methods as a separate step after ALL forwarding
1225 // pointer resolution, so that methods can be promoted in any order
1226 // with respect to their holder classes.
1227
1228 SortMethodsClosure sort;
1229 gen->ro_space()->object_iterate(&sort);
1230 gen->rw_space()->object_iterate(&sort);
1231
1232 ReinitializeTables reinit_tables(THREAD);
1233 gen->ro_space()->object_iterate(&reinit_tables);
1234 gen->rw_space()->object_iterate(&reinit_tables);
1235 tty->print_cr("done. ");
1236 tty->cr();
1237
1238 // Reorder the system dictionary. (Moving the symbols opps affects
1239 // how the hash table indices are calculated.)
1240
1241 SystemDictionary::reorder_dictionary();
1242
1243 // Empty the non-shared heap (because most of the objects were
1244 // copied out, and the remainder cannot be considered valid oops).
1245
1246 ClearSpaceClosure csc;
1247 for (int i = 0; i < gch->n_gens(); ++i) {
1248 gch->get_gen(i)->space_iterate(&csc);
1249 }
1250 csc.do_space(gen->the_space());
1251 NOT_PRODUCT(SystemDictionary::verify();)
1252
1253 // Copy the String table, the symbol table, and the system
1254 // dictionary to the shared space in usable form. Copy the hastable
1255 // buckets first [read-write], then copy the linked lists of entries
1256 // [read-only].
1257
1258 SymbolTable::reverse(extra_symbols);
1259 NOT_PRODUCT(SymbolTable::verify());
1260 SymbolTable::copy_buckets(&md_top, md_end);
1261
1262 StringTable::reverse();
1263 NOT_PRODUCT(StringTable::verify());
1264 StringTable::copy_buckets(&md_top, md_end);
1265
1266 SystemDictionary::reverse();
1267 SystemDictionary::copy_buckets(&md_top, md_end);
1268
1269 ClassLoader::verify();
1270 ClassLoader::copy_package_info_buckets(&md_top, md_end);
1271 ClassLoader::verify();
1272
1273 SymbolTable::copy_table(&md_top, md_end);
1274 StringTable::copy_table(&md_top, md_end);
1275 SystemDictionary::copy_table(&md_top, md_end);
1276 ClassLoader::verify();
1277 ClassLoader::copy_package_info_table(&md_top, md_end);
1278 ClassLoader::verify();
1279
1280 // Print debug data.
1281
1282 if (PrintSharedSpaces) {
1283 const char* fmt = "%s space: " PTR_FORMAT " out of " PTR_FORMAT " bytes allocated at " PTR_FORMAT ".";
1284 tty->print_cr(fmt, "ro", _ro_space->used(), _ro_space->capacity(),
1285 _ro_space->bottom());
1286 tty->print_cr(fmt, "rw", _rw_space->used(), _rw_space->capacity(),
1287 _rw_space->bottom());
1288 }
1289
1290 // Write the oop data to the output array.
1291
1292 WriteClosure wc(md_top, md_end);
1293 CompactingPermGenGen::serialize_oops(&wc);
1294 md_top = wc.get_top();
1295
1296 // Update the vtable pointers in all of the Klass objects in the
1297 // heap. They should point to newly generated vtable.
1298
1299 PatchKlassVtables pkvt;
1300 _rw_space->object_iterate(&pkvt);
1301 pkvt.patch(vtbl_list, vtable);
1302
1303 #ifndef PRODUCT
1304 // Update the vtable pointers in all symbols,
1305 // but only in non-product builds where symbols DO have virtual methods.
1306 PatchSymbolVtables psvt(vtbl_list, vtable);
1307 SymbolTable::symbols_do(&psvt);
1308 #endif
1309
1310 char* saved_vtbl = (char*)malloc(vtbl_list_size * sizeof(void*));
1311 memmove(saved_vtbl, vtbl_list, vtbl_list_size * sizeof(void*));
1312 memset(vtbl_list, 0, vtbl_list_size * sizeof(void*));
1313
1314 // Create and write the archive file that maps the shared spaces.
1315
1316 FileMapInfo* mapinfo = new FileMapInfo();
1317 mapinfo->populate_header(gch->gen_policy()->max_alignment());
1318
1319 // Pass 1 - update file offsets in header.
1320 mapinfo->write_header();
1321 mapinfo->write_space(CompactingPermGenGen::ro, _ro_space, true);
1322 _ro_space->set_saved_mark();
1323 mapinfo->write_space(CompactingPermGenGen::rw, _rw_space, false);
1324 _rw_space->set_saved_mark();
1325 mapinfo->write_region(CompactingPermGenGen::md, _md_vs->low(),
1326 pointer_delta(md_top, _md_vs->low(), sizeof(char)),
1327 SharedMiscDataSize,
1328 false, false);
1329 mapinfo->write_region(CompactingPermGenGen::mc, _mc_vs->low(),
1330 pointer_delta(mc_top, _mc_vs->low(), sizeof(char)),
1331 SharedMiscCodeSize,
1332 true, true);
1333
1334 // Pass 2 - write data.
1335 mapinfo->open_for_write();
1336 mapinfo->write_header();
1337 mapinfo->write_space(CompactingPermGenGen::ro, _ro_space, true);
1338 mapinfo->write_space(CompactingPermGenGen::rw, _rw_space, false);
1339 mapinfo->write_region(CompactingPermGenGen::md, _md_vs->low(),
1340 pointer_delta(md_top, _md_vs->low(), sizeof(char)),
1341 SharedMiscDataSize,
1342 false, false);
1343 mapinfo->write_region(CompactingPermGenGen::mc, _mc_vs->low(),
1344 pointer_delta(mc_top, _mc_vs->low(), sizeof(char)),
1345 SharedMiscCodeSize,
1346 true, true);
1347 mapinfo->close();
1348
1349 // Summarize heap.
1350 memmove(vtbl_list, saved_vtbl, vtbl_list_size * sizeof(void*));
1351 print_contents();
1352 }
1353 }; // class VM_PopulateDumpSharedSpace
1354
1355
1356 // Populate the shared spaces and dump to a file.
1357
1358 jint CompactingPermGenGen::dump_shared(GrowableArray<oop>* class_promote_order, TRAPS) {
1359 GenCollectedHeap* gch = GenCollectedHeap::heap();
1360
1361 // Calculate hash values for all of the (interned) strings to avoid
1362 // writes to shared pages in the future.
1363
1364 tty->print("Calculating hash values for String objects .. ");
1365 StringHashCodeClosure shcc(THREAD);
1366 StringTable::oops_do(&shcc);
1367 tty->print_cr("done. ");
1368
1369 CompactingPermGenGen* gen = (CompactingPermGenGen*)gch->perm_gen();
1370 VM_PopulateDumpSharedSpace op(class_promote_order,
1371 gen->ro_space(), gen->rw_space(),
1372 gen->md_space(), gen->mc_space());
1373 VMThread::execute(&op);
1374 return JNI_OK;
1375 }
1376
1377 void* CompactingPermGenGen::find_matching_vtbl_ptr(void** vtbl_list,
1378 void* new_vtable_start,
1379 void* obj) {
1380 void* old_vtbl_ptr = *(void**)obj;
1381 for (int i = 0; i < vtbl_list_size; i++) {
1382 if (vtbl_list[i] == old_vtbl_ptr) {
1383 return (void**)new_vtable_start + i * num_virtuals;
1384 }
1385 }
1386 ShouldNotReachHere();
1387 return NULL;
1388 }
1389
1390
1391 class LinkClassesClosure : public ObjectClosure {
1392 private:
1393 Thread* THREAD;
1394
1395 public:
1396 LinkClassesClosure(Thread* thread) : THREAD(thread) {}
1397
1398 void do_object(oop obj) {
1399 if (obj->is_klass()) {
1400 Klass* k = Klass::cast((klassOop) obj);
1401 if (k->oop_is_instance()) {
1402 instanceKlass* ik = (instanceKlass*) k;
1403 // Link the class to cause the bytecodes to be rewritten and the
1404 // cpcache to be created.
1405 if (ik->init_state() < instanceKlass::linked) {
1406 ik->link_class(THREAD);
1407 guarantee(!HAS_PENDING_EXCEPTION, "exception in class rewriting");
1408 }
1409
1410 // Create String objects from string initializer symbols.
1411 ik->constants()->resolve_string_constants(THREAD);
1412 guarantee(!HAS_PENDING_EXCEPTION, "exception resolving string constants");
1413 }
1414 }
1415 }
1416 };
1417
1418
1419 // Support for a simple checksum of the contents of the class list
1420 // file to prevent trivial tampering. The algorithm matches that in
1421 // the MakeClassList program used by the J2SE build process.
1422 #define JSUM_SEED ((jlong)CONST64(0xcafebabebabecafe))
1423 static jlong
1424 jsum(jlong start, const char *buf, const int len)
1425 {
1426 jlong h = start;
1427 char *p = (char *)buf, *e = p + len;
1428 while (p < e) {
1429 char c = *p++;
1430 if (c <= ' ') {
1431 /* Skip spaces and control characters */
1432 continue;
1433 }
1434 h = 31 * h + c;
1435 }
1436 return h;
1437 }
1438
1439
1440
1441
1442
1443 // Preload classes from a list, populate the shared spaces and dump to a
1444 // file.
1445
1446 void GenCollectedHeap::preload_and_dump(TRAPS) {
1447 TraceTime timer("Dump Shared Spaces", TraceStartupTime);
1448 ResourceMark rm;
1449
1450 // Preload classes to be shared.
1451 // Should use some os:: method rather than fopen() here. aB.
1452 // Construct the path to the class list (in jre/lib)
1453 // Walk up two directories from the location of the VM and
1454 // optionally tack on "lib" (depending on platform)
1455 char class_list_path[JVM_MAXPATHLEN];
1456 os::jvm_path(class_list_path, sizeof(class_list_path));
1457 for (int i = 0; i < 3; i++) {
1458 char *end = strrchr(class_list_path, *os::file_separator());
1459 if (end != NULL) *end = '\0';
1460 }
1461 int class_list_path_len = (int)strlen(class_list_path);
1462 if (class_list_path_len >= 3) {
1463 if (strcmp(class_list_path + class_list_path_len - 3, "lib") != 0) {
1464 strcat(class_list_path, os::file_separator());
1465 strcat(class_list_path, "lib");
1466 }
1467 }
1468 strcat(class_list_path, os::file_separator());
1469 strcat(class_list_path, "classlist");
1470
1471 FILE* file = fopen(class_list_path, "r");
1472 if (file != NULL) {
1473 jlong computed_jsum = JSUM_SEED;
1474 jlong file_jsum = 0;
1475
1476 char class_name[256];
1477 int class_count = 0;
1478 GenCollectedHeap* gch = GenCollectedHeap::heap();
1479 gch->_preloading_shared_classes = true;
1480 GrowableArray<oop>* class_promote_order = new GrowableArray<oop>();
1481
1482 // Preload (and intern) strings which will be used later.
1483
1484 StringTable::intern("main", THREAD);
1485 StringTable::intern("([Ljava/lang/String;)V", THREAD);
1486 StringTable::intern("Ljava/lang/Class;", THREAD);
1487
1488 StringTable::intern("I", THREAD); // Needed for StringBuffer persistence?
1489 StringTable::intern("Z", THREAD); // Needed for StringBuffer persistence?
1490
1491 // sun.io.Converters
1492 static const char obj_array_sig[] = "[[Ljava/lang/Object;";
1493 SymbolTable::lookup(obj_array_sig, (int)strlen(obj_array_sig), THREAD);
1494
1495 // java.util.HashMap
1496 static const char map_entry_array_sig[] = "[Ljava/util/Map$Entry;";
1497 SymbolTable::lookup(map_entry_array_sig, (int)strlen(map_entry_array_sig),
1498 THREAD);
1499
1500 tty->print("Loading classes to share ... ");
1501 while ((fgets(class_name, sizeof class_name, file)) != NULL) {
1502 if (*class_name == '#') {
1503 jint fsh, fsl;
1504 if (sscanf(class_name, "# %8x%8x\n", &fsh, &fsl) == 2) {
1505 file_jsum = ((jlong)(fsh) << 32) | (fsl & 0xffffffff);
1506 }
1507
1508 continue;
1509 }
1510 // Remove trailing newline
1511 size_t name_len = strlen(class_name);
1512 class_name[name_len-1] = '\0';
1513
1514 computed_jsum = jsum(computed_jsum, class_name, (const int)name_len - 1);
1515
1516 // Got a class name - load it.
1517 TempNewSymbol class_name_symbol = SymbolTable::new_symbol(class_name, THREAD);
1518 guarantee(!HAS_PENDING_EXCEPTION, "Exception creating a symbol.");
1519 klassOop klass = SystemDictionary::resolve_or_null(class_name_symbol,
1520 THREAD);
1521 guarantee(!HAS_PENDING_EXCEPTION, "Exception resolving a class.");
1522 if (klass != NULL) {
1523 if (PrintSharedSpaces) {
1524 tty->print_cr("Shared spaces preloaded: %s", class_name);
1525 }
1526
1527
1528 instanceKlass* ik = instanceKlass::cast(klass);
1529
1530 // Should be class load order as per -XX:+TraceClassLoadingPreorder
1531 class_promote_order->append(ik->as_klassOop());
1532
1533 // Link the class to cause the bytecodes to be rewritten and the
1534 // cpcache to be created. The linking is done as soon as classes
1535 // are loaded in order that the related data structures (klass,
1536 // cpCache, Sting constants) are located together.
1537
1538 if (ik->init_state() < instanceKlass::linked) {
1539 ik->link_class(THREAD);
1540 guarantee(!(HAS_PENDING_EXCEPTION), "exception in class rewriting");
1541 }
1542
1543 // Create String objects from string initializer symbols.
1544
1545 ik->constants()->resolve_string_constants(THREAD);
1546
1547 class_count++;
1548 } else {
1549 if (PrintSharedSpaces) {
1550 tty->cr();
1551 tty->print_cr(" Preload failed: %s", class_name);
1552 }
1553 }
1554 file_jsum = 0; // Checksum must be on last line of file
1555 }
1556 if (computed_jsum != file_jsum) {
1557 tty->cr();
1558 tty->print_cr("Preload failed: checksum of class list was incorrect.");
1559 exit(1);
1560 }
1561
1562 tty->print_cr("done. ");
1563
1564 if (PrintSharedSpaces) {
1565 tty->print_cr("Shared spaces: preloaded %d classes", class_count);
1566 }
1567
1568 // Rewrite and unlink classes.
1569 tty->print("Rewriting and unlinking classes ... ");
1570 // Make heap parsable
1571 ensure_parsability(false); // arg is actually don't care
1572
1573 // Link any classes which got missed. (It's not quite clear why
1574 // they got missed.) This iteration would be unsafe if we weren't
1575 // single-threaded at this point; however we can't do it on the VM
1576 // thread because it requires object allocation.
1577 LinkClassesClosure lcc(Thread::current());
1578 object_iterate(&lcc);
1579 ensure_parsability(false); // arg is actually don't care
1580 tty->print_cr("done. ");
1581
1582 // Create and dump the shared spaces.
1583 jint err = CompactingPermGenGen::dump_shared(class_promote_order, THREAD);
1584 if (err != JNI_OK) {
1585 fatal("Dumping shared spaces failed.");
1586 }
1587
1588 } else {
1589 char errmsg[JVM_MAXPATHLEN];
1590 os::lasterror(errmsg, JVM_MAXPATHLEN);
1591 tty->print_cr("Loading classlist failed: %s", errmsg);
1592 exit(1);
1593 }
1594
1595 // Since various initialization steps have been undone by this process,
1596 // it is not reasonable to continue running a java process.
1597 exit(0);
1598 }