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 // Itable indices are calculated based on methods array order 627 // (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 ReinitializeItables: public ObjectClosure { 634 private: 635 Thread* _thread; 636 637 public: 638 ReinitializeItables(Thread* thread) : _thread(thread) {} 639 640 void do_object(oop obj) { 641 if (obj->blueprint()->oop_is_instanceKlass()) { 642 instanceKlass* ik = instanceKlass::cast((klassOop)obj); 643 ik->itable()->initialize_itable(false, _thread); 644 } 645 } 646 }; 647 648 649 // Adjust references in oops to refer to shared spaces. 650 651 class PatchOopsClosure: public ObjectClosure { 652 private: 653 Thread* _thread; 654 ResolveForwardingClosure resolve; 655 656 public: 657 PatchOopsClosure(Thread* thread) : _thread(thread) {} 658 659 void do_object(oop obj) { 660 obj->oop_iterate_header(&resolve); 661 obj->oop_iterate(&resolve); 662 663 assert(obj->klass()->is_shared(), "Klass not pointing into shared space."); 664 665 // If the object is a Java object or class which might (in the 666 // future) contain a reference to a young gen object, add it to the 667 // list. 668 669 if (obj->is_klass() || obj->is_instance()) { 670 if (obj->is_klass() || 671 obj->is_a(SystemDictionary::Class_klass()) || 672 obj->is_a(SystemDictionary::Throwable_klass())) { 673 // Do nothing 674 } 675 else if (obj->is_a(SystemDictionary::String_klass())) { 676 // immutable objects. 677 } else { 678 // someone added an object we hadn't accounted for. 679 ShouldNotReachHere(); 680 } 681 } 682 } 683 }; 684 685 686 // Empty the young and old generations. 687 688 class ClearSpaceClosure : public SpaceClosure { 689 public: 690 void do_space(Space* s) { 691 s->clear(SpaceDecorator::Mangle); 692 } 693 }; 694 695 696 // Closure for serializing initialization data out to a data area to be 697 // written to the shared file. 698 699 class WriteClosure : public SerializeOopClosure { 700 private: 701 oop* top; 702 char* end; 703 704 inline void check_space() { 705 if ((char*)top + sizeof(oop) > end) { 706 report_out_of_shared_space(SharedMiscData); 707 } 708 } 709 710 711 public: 712 WriteClosure(char* md_top, char* md_end) { 713 top = (oop*)md_top; 714 end = md_end; 715 } 716 717 char* get_top() { return (char*)top; } 718 719 void do_oop(oop* p) { 720 check_space(); 721 oop obj = *p; 722 assert(obj->is_oop_or_null(), "invalid oop"); 723 assert(obj == NULL || obj->is_shared(), 724 "Oop in shared space not pointing into shared space."); 725 *top = obj; 726 ++top; 727 } 728 729 void do_oop(narrowOop* pobj) { ShouldNotReachHere(); } 730 731 void do_int(int* p) { 732 check_space(); 733 *top = (oop)(intptr_t)*p; 734 ++top; 735 } 736 737 void do_size_t(size_t* p) { 738 check_space(); 739 *top = (oop)(intptr_t)*p; 740 ++top; 741 } 742 743 void do_ptr(void** p) { 744 check_space(); 745 *top = (oop)*p; 746 ++top; 747 } 748 749 void do_ptr(HeapWord** p) { do_ptr((void **) p); } 750 751 void do_tag(int tag) { 752 check_space(); 753 *top = (oop)(intptr_t)tag; 754 ++top; 755 } 756 757 void do_region(u_char* start, size_t size) { 758 if ((char*)top + size > end) { 759 report_out_of_shared_space(SharedMiscData); 760 } 761 assert((intptr_t)start % sizeof(oop) == 0, "bad alignment"); 762 assert(size % sizeof(oop) == 0, "bad size"); 763 do_tag((int)size); 764 while (size > 0) { 765 *top = *(oop*)start; 766 ++top; 767 start += sizeof(oop); 768 size -= sizeof(oop); 769 } 770 } 771 772 bool reading() const { return false; } 773 }; 774 775 776 class ResolveConstantPoolsClosure : public ObjectClosure { 777 private: 778 TRAPS; 779 public: 780 ResolveConstantPoolsClosure(Thread *t) { 781 __the_thread__ = t; 782 } 783 void do_object(oop obj) { 784 if (obj->is_constantPool()) { 785 constantPoolOop cpool = (constantPoolOop)obj; 786 int unresolved = cpool->pre_resolve_shared_klasses(THREAD); 787 } 788 } 789 }; 790 791 792 // Print a summary of the contents of the read/write spaces to help 793 // identify objects which might be able to be made read-only. At this 794 // point, the objects have been written, and we can trash them as 795 // needed. 796 797 static void print_contents() { 798 if (PrintSharedSpaces) { 799 GenCollectedHeap* gch = GenCollectedHeap::heap(); 800 CompactingPermGenGen* gen = (CompactingPermGenGen*)gch->perm_gen(); 801 802 // High level summary of the read-only space: 803 804 ClassifyObjectClosure coc; 805 tty->cr(); tty->print_cr("ReadOnly space:"); 806 gen->ro_space()->object_iterate(&coc); 807 coc.print(); 808 809 // High level summary of the read-write space: 810 811 coc.reset(); 812 tty->cr(); tty->print_cr("ReadWrite space:"); 813 gen->rw_space()->object_iterate(&coc); 814 coc.print(); 815 816 // Reset counters 817 818 ClearAllocCountClosure cacc; 819 gen->ro_space()->object_iterate(&cacc); 820 gen->rw_space()->object_iterate(&cacc); 821 coc.reset(); 822 823 // Lower level summary of the read-only space: 824 825 gen->ro_space()->object_iterate(&coc); 826 tty->cr(); tty->print_cr("ReadOnly space:"); 827 ClassifyInstanceKlassClosure cikc; 828 gen->rw_space()->object_iterate(&cikc); 829 cikc.print(); 830 831 // Reset counters 832 833 gen->ro_space()->object_iterate(&cacc); 834 gen->rw_space()->object_iterate(&cacc); 835 coc.reset(); 836 837 // Lower level summary of the read-write space: 838 839 gen->rw_space()->object_iterate(&coc); 840 cikc.reset(); 841 tty->cr(); tty->print_cr("ReadWrite space:"); 842 gen->rw_space()->object_iterate(&cikc); 843 cikc.print(); 844 } 845 } 846 847 848 // Patch C++ vtable pointer in klass oops. 849 850 // Klass objects contain references to c++ vtables in the JVM library. 851 // Fix them to point to our constructed vtables. However, don't iterate 852 // across the space while doing this, as that causes the vtables to be 853 // patched, undoing our useful work. Instead, iterate to make a list, 854 // then use the list to do the fixing. 855 // 856 // Our constructed vtables: 857 // Dump time: 858 // 1. init_self_patching_vtbl_list: table of pointers to current virtual method addrs 859 // 2. generate_vtable_methods: create jump table, appended to above vtbl_list 860 // 3. PatchKlassVtables: for Klass list, patch the vtable entry to point to jump table 861 // rather than to current vtbl 862 // Table layout: NOTE FIXED SIZE 863 // 1. vtbl pointers 864 // 2. #Klass X #virtual methods per Klass 865 // 1 entry for each, in the order: 866 // Klass1:method1 entry, Klass1:method2 entry, ... Klass1:method<num_virtuals> entry 867 // Klass2:method1 entry, Klass2:method2 entry, ... Klass2:method<num_virtuals> entry 868 // ... 869 // Klass<vtbl_list_size>:method1 entry, Klass<vtbl_list_size>:method2 entry, 870 // ... Klass<vtbl_list_size>:method<num_virtuals> entry 871 // Sample entry: (Sparc): 872 // save(sp, -256, sp) 873 // ba,pt common_code 874 // mov XXX, %L0 %L0 gets: Klass index <<8 + method index (note: max method index 255) 875 // 876 // Restore time: 877 // 1. initialize_oops: reserve space for table 878 // 2. init_self_patching_vtbl_list: update pointers to NEW virtual method addrs in text 879 // 880 // Execution time: 881 // First virtual method call for any object of these Klass types: 882 // 1. object->klass->klass_part 883 // 2. vtable entry for that klass_part points to the jump table entries 884 // 3. branches to common_code with %O0/klass_part, %L0: Klass index <<8 + method index 885 // 4. common_code: 886 // Get address of new vtbl pointer for this Klass from updated table 887 // Update new vtbl pointer in the Klass: future virtual calls go direct 888 // Jump to method, using new vtbl pointer and method index 889 890 class PatchKlassVtables: public ObjectClosure { 891 private: 892 GrowableArray<klassOop>* _klass_objects; 893 894 public: 895 PatchKlassVtables() { 896 _klass_objects = new GrowableArray<klassOop>(); 897 } 898 899 void do_object(oop obj) { 900 if (obj->is_klass()) { 901 _klass_objects->append(klassOop(obj)); 902 } 903 } 904 905 void patch(void** vtbl_list, void* new_vtable_start) { 906 int n = _klass_objects->length(); 907 for (int i = 0; i < n; i++) { 908 klassOop obj = (klassOop)_klass_objects->at(i); 909 Klass* k = obj->klass_part(); 910 *(void**)k = CompactingPermGenGen::find_matching_vtbl_ptr( 911 vtbl_list, new_vtable_start, k); 912 } 913 } 914 }; 915 916 // Walk through all symbols and patch their vtable pointers. 917 // Note that symbols have vtable pointers only in non-product builds 918 // (see allocation.hpp). 919 920 #ifndef PRODUCT 921 class PatchSymbolVtables: public SymbolClosure { 922 private: 923 void* _new_vtbl_ptr; 924 925 public: 926 PatchSymbolVtables(void** vtbl_list, void* new_vtable_start) { 927 Symbol s; 928 _new_vtbl_ptr = CompactingPermGenGen::find_matching_vtbl_ptr( 929 vtbl_list, new_vtable_start, &s); 930 } 931 932 void do_symbol(Symbol** p) { 933 Symbol* sym = load_symbol(p); 934 *(void**)sym = _new_vtbl_ptr; 935 } 936 }; 937 #endif 938 939 940 // Populate the shared space. 941 942 class VM_PopulateDumpSharedSpace: public VM_Operation { 943 private: 944 GrowableArray<oop> *_class_promote_order; 945 OffsetTableContigSpace* _ro_space; 946 OffsetTableContigSpace* _rw_space; 947 VirtualSpace* _md_vs; 948 VirtualSpace* _mc_vs; 949 950 public: 951 VM_PopulateDumpSharedSpace(GrowableArray<oop> *class_promote_order, 952 OffsetTableContigSpace* ro_space, 953 OffsetTableContigSpace* rw_space, 954 VirtualSpace* md_vs, VirtualSpace* mc_vs) { 955 _class_promote_order = class_promote_order; 956 _ro_space = ro_space; 957 _rw_space = rw_space; 958 _md_vs = md_vs; 959 _mc_vs = mc_vs; 960 } 961 962 VMOp_Type type() const { return VMOp_PopulateDumpSharedSpace; } 963 void doit() { 964 Thread* THREAD = VMThread::vm_thread(); 965 NOT_PRODUCT(SystemDictionary::verify();) 966 // The following guarantee is meant to ensure that no loader constraints 967 // exist yet, since the constraints table is not shared. This becomes 968 // more important now that we don't re-initialize vtables/itables for 969 // shared classes at runtime, where constraints were previously created. 970 guarantee(SystemDictionary::constraints()->number_of_entries() == 0, 971 "loader constraints are not saved"); 972 // Revisit and implement this if we prelink method handle call sites: 973 guarantee(SystemDictionary::invoke_method_table() == NULL || 974 SystemDictionary::invoke_method_table()->number_of_entries() == 0, 975 "invoke method table is not saved"); 976 GenCollectedHeap* gch = GenCollectedHeap::heap(); 977 978 // At this point, many classes have been loaded. 979 980 // Update all the fingerprints in the shared methods. 981 982 tty->print("Calculating fingerprints ... "); 983 FingerprintMethodsClosure fpmc; 984 gch->object_iterate(&fpmc); 985 tty->print_cr("done. "); 986 987 // Remove all references outside the heap. 988 989 tty->print("Removing unshareable information ... "); 990 RemoveUnshareableInfoClosure ruic; 991 gch->object_iterate(&ruic); 992 tty->print_cr("done. "); 993 994 // Move the objects in three passes. 995 996 MarkObjectsOopClosure mark_all; 997 MarkCommonReadOnly mark_common_ro; 998 MarkStringValues mark_string_values; 999 MarkReadWriteObjects mark_rw; 1000 MarkStringObjects mark_strings; 1001 MoveMarkedObjects move_ro(_ro_space, true); 1002 MoveMarkedObjects move_rw(_rw_space, false); 1003 1004 // The SharedOptimizeColdStart VM option governs the new layout 1005 // algorithm for promoting classes into the shared archive. 1006 // The general idea is to minimize cold start time by laying 1007 // out the objects in the order they are accessed at startup time. 1008 // By doing this we are trying to eliminate out-of-order accesses 1009 // in the shared archive. This benefits cold startup time by making 1010 // disk reads as sequential as possible during class loading and 1011 // bootstrapping activities. There may also be a small secondary 1012 // effect of better "packing" of more commonly used data on a smaller 1013 // number of pages, although no direct benefit has been measured from 1014 // this effect. 1015 // 1016 // At the class level of granularity, the promotion order is dictated 1017 // by the classlist file whose generation is discussed elsewhere. 1018 // 1019 // At smaller granularity, optimal ordering was determined by an 1020 // offline analysis of object access order in the shared archive. 1021 // The dbx watchpoint facility, combined with SA post-processing, 1022 // was used to observe common access patterns primarily during 1023 // classloading. This information was used to craft the promotion 1024 // order seen in the following closures. 1025 // 1026 // The observed access order is mostly governed by what happens 1027 // in SystemDictionary::load_shared_class(). NOTE WELL - care 1028 // should be taken when making changes to this method, because it 1029 // may invalidate assumptions made about access order! 1030 // 1031 // (Ideally, there would be a better way to manage changes to 1032 // the access order. Unfortunately a generic in-VM solution for 1033 // dynamically observing access order and optimizing shared 1034 // archive layout is pretty difficult. We go with the static 1035 // analysis because the code is fairly mature at this point 1036 // and we're betting that the access order won't change much.) 1037 1038 MarkAndMoveOrderedReadOnly mark_and_move_ordered_ro(&move_ro); 1039 MarkAndMoveOrderedReadWrite mark_and_move_ordered_rw(&move_rw); 1040 1041 // Set up the share data and shared code segments. 1042 1043 char* md_top = _md_vs->low(); 1044 char* md_end = _md_vs->high(); 1045 char* mc_top = _mc_vs->low(); 1046 char* mc_end = _mc_vs->high(); 1047 1048 // Reserve space for the list of klassOops whose vtables are used 1049 // for patching others as needed. 1050 1051 void** vtbl_list = (void**)md_top; 1052 int vtbl_list_size = CompactingPermGenGen::vtbl_list_size; 1053 Universe::init_self_patching_vtbl_list(vtbl_list, vtbl_list_size); 1054 1055 md_top += vtbl_list_size * sizeof(void*); 1056 void* vtable = md_top; 1057 1058 // Reserve space for a new dummy vtable for klass objects in the 1059 // heap. Generate self-patching vtable entries. 1060 1061 CompactingPermGenGen::generate_vtable_methods(vtbl_list, 1062 &vtable, 1063 &md_top, md_end, 1064 &mc_top, mc_end); 1065 1066 // Reserve space for the total size and the number of stored symbols. 1067 1068 md_top += sizeof(intptr_t) * 2; 1069 1070 MoveSymbols move_symbols(md_top, md_end); 1071 CommonSymbolsClosure traverse_common_symbols(&move_symbols); 1072 1073 // Phase 1a: remove symbols with _refcount == 0 1074 1075 SymbolTable::unlink(); 1076 1077 // Phase 1b: move commonly used symbols referenced by oop fields. 1078 1079 tty->print("Moving common symbols to metadata section at " PTR_FORMAT " ... ", 1080 move_symbols.get_top()); 1081 gch->object_iterate(&traverse_common_symbols); 1082 tty->print_cr("done. "); 1083 1084 // Phase 1c: move known names and signatures. 1085 1086 tty->print("Moving vmSymbols to metadata section at " PTR_FORMAT " ... ", 1087 move_symbols.get_top()); 1088 vmSymbols::symbols_do(&move_symbols); 1089 tty->print_cr("done. "); 1090 1091 // Phase 1d: move the remaining symbols by scanning the whole SymbolTable. 1092 1093 void* extra_symbols = move_symbols.get_top(); 1094 tty->print("Moving the remaining symbols to metadata section at " PTR_FORMAT " ... ", 1095 move_symbols.get_top()); 1096 SymbolTable::symbols_do(&move_symbols); 1097 tty->print_cr("done. "); 1098 1099 // Record the total length of all symbols at the beginning of the block. 1100 ((intptr_t*)md_top)[-2] = move_symbols.get_top() - md_top; 1101 ((intptr_t*)md_top)[-1] = move_symbols.count(); 1102 tty->print_cr("Moved %d symbols, %d bytes.", 1103 move_symbols.count(), move_symbols.get_top() - md_top); 1104 // Advance the pointer to the end of symbol store. 1105 md_top = move_symbols.get_top(); 1106 1107 1108 // Phase 2: move commonly used read-only objects to the read-only space. 1109 1110 if (SharedOptimizeColdStart) { 1111 tty->print("Moving pre-ordered read-only objects to shared space at " PTR_FORMAT " ... ", 1112 _ro_space->top()); 1113 for (int i = 0; i < _class_promote_order->length(); i++) { 1114 oop obj = _class_promote_order->at(i); 1115 mark_and_move_ordered_ro.do_object(obj); 1116 } 1117 tty->print_cr("done. "); 1118 } 1119 1120 tty->print("Moving read-only objects to shared space at " PTR_FORMAT " ... ", 1121 _ro_space->top()); 1122 gch->object_iterate(&mark_common_ro); 1123 gch->object_iterate(&move_ro); 1124 tty->print_cr("done. "); 1125 1126 // Phase 3: move String character arrays to the read-only space. 1127 1128 tty->print("Moving string char arrays to shared space at " PTR_FORMAT " ... ", 1129 _ro_space->top()); 1130 gch->object_iterate(&mark_string_values); 1131 gch->object_iterate(&move_ro); 1132 tty->print_cr("done. "); 1133 1134 // Phase 4: move read-write objects to the read-write space, except 1135 // Strings. 1136 1137 if (SharedOptimizeColdStart) { 1138 tty->print("Moving pre-ordered read-write objects to shared space at " PTR_FORMAT " ... ", 1139 _rw_space->top()); 1140 for (int i = 0; i < _class_promote_order->length(); i++) { 1141 oop obj = _class_promote_order->at(i); 1142 mark_and_move_ordered_rw.do_object(obj); 1143 } 1144 tty->print_cr("done. "); 1145 } 1146 tty->print("Moving read-write objects to shared space at " PTR_FORMAT " ... ", 1147 _rw_space->top()); 1148 Universe::oops_do(&mark_all, true); 1149 SystemDictionary::oops_do(&mark_all); 1150 oop tmp = Universe::arithmetic_exception_instance(); 1151 mark_object(java_lang_Throwable::message(tmp)); 1152 gch->object_iterate(&mark_rw); 1153 gch->object_iterate(&move_rw); 1154 tty->print_cr("done. "); 1155 1156 // Phase 5: move String objects to the read-write space. 1157 1158 tty->print("Moving String objects to shared space at " PTR_FORMAT " ... ", 1159 _rw_space->top()); 1160 StringTable::oops_do(&mark_all); 1161 gch->object_iterate(&mark_strings); 1162 gch->object_iterate(&move_rw); 1163 tty->print_cr("done. "); 1164 tty->print_cr("Read-write space ends at " PTR_FORMAT ", %d bytes.", 1165 _rw_space->top(), _rw_space->used()); 1166 1167 #ifdef DEBUG 1168 // Check: scan for objects which were not moved. 1169 1170 CheckRemainingObjects check_objects; 1171 gch->object_iterate(&check_objects); 1172 check_objects.status(); 1173 #endif 1174 1175 // Resolve forwarding in objects and saved C++ structures 1176 tty->print("Updating references to shared objects ... "); 1177 ResolveForwardingClosure resolve; 1178 Universe::oops_do(&resolve); 1179 SystemDictionary::oops_do(&resolve); 1180 StringTable::oops_do(&resolve); 1181 1182 // Fix (forward) all of the references in these shared objects (which 1183 // are required to point ONLY to objects in the shared spaces). 1184 // Also, create a list of all objects which might later contain a 1185 // reference to a younger generation object. 1186 1187 CompactingPermGenGen* gen = (CompactingPermGenGen*)gch->perm_gen(); 1188 PatchOopsClosure patch(THREAD); 1189 gen->ro_space()->object_iterate(&patch); 1190 gen->rw_space()->object_iterate(&patch); 1191 1192 // Previously method sorting was done concurrently with forwarding 1193 // pointer resolution in the shared spaces. This imposed an ordering 1194 // restriction in that methods were required to be promoted/patched 1195 // before their holder classes. (Because constant pool pointers in 1196 // methodKlasses are required to be resolved before their holder class 1197 // is visited for sorting, otherwise methods are sorted by incorrect, 1198 // pre-forwarding addresses.) 1199 // 1200 // Now, we reorder methods as a separate step after ALL forwarding 1201 // pointer resolution, so that methods can be promoted in any order 1202 // with respect to their holder classes. 1203 1204 SortMethodsClosure sort; 1205 gen->ro_space()->object_iterate(&sort); 1206 gen->rw_space()->object_iterate(&sort); 1207 1208 ReinitializeItables reinit_itables(THREAD); 1209 gen->ro_space()->object_iterate(&reinit_itables); 1210 gen->rw_space()->object_iterate(&reinit_itables); 1211 tty->print_cr("done. "); 1212 tty->cr(); 1213 1214 // Reorder the system dictionary. (Moving the symbols opps affects 1215 // how the hash table indices are calculated.) 1216 1217 SystemDictionary::reorder_dictionary(); 1218 1219 // Empty the non-shared heap (because most of the objects were 1220 // copied out, and the remainder cannot be considered valid oops). 1221 1222 ClearSpaceClosure csc; 1223 for (int i = 0; i < gch->n_gens(); ++i) { 1224 gch->get_gen(i)->space_iterate(&csc); 1225 } 1226 csc.do_space(gen->the_space()); 1227 NOT_PRODUCT(SystemDictionary::verify();) 1228 1229 // Copy the String table, the symbol table, and the system 1230 // dictionary to the shared space in usable form. Copy the hastable 1231 // buckets first [read-write], then copy the linked lists of entries 1232 // [read-only]. 1233 1234 SymbolTable::reverse(extra_symbols); 1235 NOT_PRODUCT(SymbolTable::verify()); 1236 SymbolTable::copy_buckets(&md_top, md_end); 1237 1238 StringTable::reverse(); 1239 NOT_PRODUCT(StringTable::verify()); 1240 StringTable::copy_buckets(&md_top, md_end); 1241 1242 SystemDictionary::reverse(); 1243 SystemDictionary::copy_buckets(&md_top, md_end); 1244 1245 ClassLoader::verify(); 1246 ClassLoader::copy_package_info_buckets(&md_top, md_end); 1247 ClassLoader::verify(); 1248 1249 SymbolTable::copy_table(&md_top, md_end); 1250 StringTable::copy_table(&md_top, md_end); 1251 SystemDictionary::copy_table(&md_top, md_end); 1252 ClassLoader::verify(); 1253 ClassLoader::copy_package_info_table(&md_top, md_end); 1254 ClassLoader::verify(); 1255 1256 // Print debug data. 1257 1258 if (PrintSharedSpaces) { 1259 const char* fmt = "%s space: " PTR_FORMAT " out of " PTR_FORMAT " bytes allocated at " PTR_FORMAT "."; 1260 tty->print_cr(fmt, "ro", _ro_space->used(), _ro_space->capacity(), 1261 _ro_space->bottom()); 1262 tty->print_cr(fmt, "rw", _rw_space->used(), _rw_space->capacity(), 1263 _rw_space->bottom()); 1264 } 1265 1266 // Write the oop data to the output array. 1267 1268 WriteClosure wc(md_top, md_end); 1269 CompactingPermGenGen::serialize_oops(&wc); 1270 md_top = wc.get_top(); 1271 1272 // Update the vtable pointers in all of the Klass objects in the 1273 // heap. They should point to newly generated vtable. 1274 1275 PatchKlassVtables pkvt; 1276 _rw_space->object_iterate(&pkvt); 1277 pkvt.patch(vtbl_list, vtable); 1278 1279 #ifndef PRODUCT 1280 // Update the vtable pointers in all symbols, 1281 // but only in non-product builds where symbols DO have virtual methods. 1282 PatchSymbolVtables psvt(vtbl_list, vtable); 1283 SymbolTable::symbols_do(&psvt); 1284 #endif 1285 1286 char* saved_vtbl = (char*)malloc(vtbl_list_size * sizeof(void*)); 1287 memmove(saved_vtbl, vtbl_list, vtbl_list_size * sizeof(void*)); 1288 memset(vtbl_list, 0, vtbl_list_size * sizeof(void*)); 1289 1290 // Create and write the archive file that maps the shared spaces. 1291 1292 FileMapInfo* mapinfo = new FileMapInfo(); 1293 mapinfo->populate_header(gch->gen_policy()->max_alignment()); 1294 1295 // Pass 1 - update file offsets in header. 1296 mapinfo->write_header(); 1297 mapinfo->write_space(CompactingPermGenGen::ro, _ro_space, true); 1298 _ro_space->set_saved_mark(); 1299 mapinfo->write_space(CompactingPermGenGen::rw, _rw_space, false); 1300 _rw_space->set_saved_mark(); 1301 mapinfo->write_region(CompactingPermGenGen::md, _md_vs->low(), 1302 pointer_delta(md_top, _md_vs->low(), sizeof(char)), 1303 SharedMiscDataSize, 1304 false, false); 1305 mapinfo->write_region(CompactingPermGenGen::mc, _mc_vs->low(), 1306 pointer_delta(mc_top, _mc_vs->low(), sizeof(char)), 1307 SharedMiscCodeSize, 1308 true, true); 1309 1310 // Pass 2 - write data. 1311 mapinfo->open_for_write(); 1312 mapinfo->write_header(); 1313 mapinfo->write_space(CompactingPermGenGen::ro, _ro_space, true); 1314 mapinfo->write_space(CompactingPermGenGen::rw, _rw_space, false); 1315 mapinfo->write_region(CompactingPermGenGen::md, _md_vs->low(), 1316 pointer_delta(md_top, _md_vs->low(), sizeof(char)), 1317 SharedMiscDataSize, 1318 false, false); 1319 mapinfo->write_region(CompactingPermGenGen::mc, _mc_vs->low(), 1320 pointer_delta(mc_top, _mc_vs->low(), sizeof(char)), 1321 SharedMiscCodeSize, 1322 true, true); 1323 mapinfo->close(); 1324 1325 // Summarize heap. 1326 memmove(vtbl_list, saved_vtbl, vtbl_list_size * sizeof(void*)); 1327 print_contents(); 1328 } 1329 }; // class VM_PopulateDumpSharedSpace 1330 1331 1332 // Populate the shared spaces and dump to a file. 1333 1334 jint CompactingPermGenGen::dump_shared(GrowableArray<oop>* class_promote_order, TRAPS) { 1335 GenCollectedHeap* gch = GenCollectedHeap::heap(); 1336 1337 // Calculate hash values for all of the (interned) strings to avoid 1338 // writes to shared pages in the future. 1339 1340 tty->print("Calculating hash values for String objects .. "); 1341 StringHashCodeClosure shcc(THREAD); 1342 StringTable::oops_do(&shcc); 1343 tty->print_cr("done. "); 1344 1345 CompactingPermGenGen* gen = (CompactingPermGenGen*)gch->perm_gen(); 1346 VM_PopulateDumpSharedSpace op(class_promote_order, 1347 gen->ro_space(), gen->rw_space(), 1348 gen->md_space(), gen->mc_space()); 1349 VMThread::execute(&op); 1350 return JNI_OK; 1351 } 1352 1353 void* CompactingPermGenGen::find_matching_vtbl_ptr(void** vtbl_list, 1354 void* new_vtable_start, 1355 void* obj) { 1356 void* old_vtbl_ptr = *(void**)obj; 1357 for (int i = 0; i < vtbl_list_size; i++) { 1358 if (vtbl_list[i] == old_vtbl_ptr) { 1359 return (void**)new_vtable_start + i * num_virtuals; 1360 } 1361 } 1362 ShouldNotReachHere(); 1363 return NULL; 1364 } 1365 1366 1367 class LinkClassesClosure : public ObjectClosure { 1368 private: 1369 Thread* THREAD; 1370 1371 public: 1372 LinkClassesClosure(Thread* thread) : THREAD(thread) {} 1373 1374 void do_object(oop obj) { 1375 if (obj->is_klass()) { 1376 Klass* k = Klass::cast((klassOop) obj); 1377 if (k->oop_is_instance()) { 1378 instanceKlass* ik = (instanceKlass*) k; 1379 // Link the class to cause the bytecodes to be rewritten and the 1380 // cpcache to be created. 1381 if (ik->get_init_state() < instanceKlass::linked) { 1382 ik->link_class(THREAD); 1383 guarantee(!HAS_PENDING_EXCEPTION, "exception in class rewriting"); 1384 } 1385 1386 // Create String objects from string initializer symbols. 1387 ik->constants()->resolve_string_constants(THREAD); 1388 guarantee(!HAS_PENDING_EXCEPTION, "exception resolving string constants"); 1389 } 1390 } 1391 } 1392 }; 1393 1394 1395 // Support for a simple checksum of the contents of the class list 1396 // file to prevent trivial tampering. The algorithm matches that in 1397 // the MakeClassList program used by the J2SE build process. 1398 #define JSUM_SEED ((jlong)CONST64(0xcafebabebabecafe)) 1399 static jlong 1400 jsum(jlong start, const char *buf, const int len) 1401 { 1402 jlong h = start; 1403 char *p = (char *)buf, *e = p + len; 1404 while (p < e) { 1405 char c = *p++; 1406 if (c <= ' ') { 1407 /* Skip spaces and control characters */ 1408 continue; 1409 } 1410 h = 31 * h + c; 1411 } 1412 return h; 1413 } 1414 1415 1416 1417 1418 1419 // Preload classes from a list, populate the shared spaces and dump to a 1420 // file. 1421 1422 void GenCollectedHeap::preload_and_dump(TRAPS) { 1423 TraceTime timer("Dump Shared Spaces", TraceStartupTime); 1424 ResourceMark rm; 1425 1426 // Preload classes to be shared. 1427 // Should use some os:: method rather than fopen() here. aB. 1428 // Construct the path to the class list (in jre/lib) 1429 // Walk up two directories from the location of the VM and 1430 // optionally tack on "lib" (depending on platform) 1431 char class_list_path[JVM_MAXPATHLEN]; 1432 os::jvm_path(class_list_path, sizeof(class_list_path)); 1433 for (int i = 0; i < 3; i++) { 1434 char *end = strrchr(class_list_path, *os::file_separator()); 1435 if (end != NULL) *end = '\0'; 1436 } 1437 int class_list_path_len = (int)strlen(class_list_path); 1438 if (class_list_path_len >= 3) { 1439 if (strcmp(class_list_path + class_list_path_len - 3, "lib") != 0) { 1440 strcat(class_list_path, os::file_separator()); 1441 strcat(class_list_path, "lib"); 1442 } 1443 } 1444 strcat(class_list_path, os::file_separator()); 1445 strcat(class_list_path, "classlist"); 1446 1447 FILE* file = fopen(class_list_path, "r"); 1448 if (file != NULL) { 1449 jlong computed_jsum = JSUM_SEED; 1450 jlong file_jsum = 0; 1451 1452 char class_name[256]; 1453 int class_count = 0; 1454 GenCollectedHeap* gch = GenCollectedHeap::heap(); 1455 gch->_preloading_shared_classes = true; 1456 GrowableArray<oop>* class_promote_order = new GrowableArray<oop>(); 1457 1458 // Preload (and intern) strings which will be used later. 1459 1460 StringTable::intern("main", THREAD); 1461 StringTable::intern("([Ljava/lang/String;)V", THREAD); 1462 StringTable::intern("Ljava/lang/Class;", THREAD); 1463 1464 StringTable::intern("I", THREAD); // Needed for StringBuffer persistence? 1465 StringTable::intern("Z", THREAD); // Needed for StringBuffer persistence? 1466 1467 // sun.io.Converters 1468 static const char obj_array_sig[] = "[[Ljava/lang/Object;"; 1469 SymbolTable::lookup(obj_array_sig, (int)strlen(obj_array_sig), THREAD); 1470 1471 // java.util.HashMap 1472 static const char map_entry_array_sig[] = "[Ljava/util/Map$Entry;"; 1473 SymbolTable::lookup(map_entry_array_sig, (int)strlen(map_entry_array_sig), 1474 THREAD); 1475 1476 tty->print("Loading classes to share ... "); 1477 while ((fgets(class_name, sizeof class_name, file)) != NULL) { 1478 if (*class_name == '#') { 1479 jint fsh, fsl; 1480 if (sscanf(class_name, "# %8x%8x\n", &fsh, &fsl) == 2) { 1481 file_jsum = ((jlong)(fsh) << 32) | (fsl & 0xffffffff); 1482 } 1483 1484 continue; 1485 } 1486 // Remove trailing newline 1487 size_t name_len = strlen(class_name); 1488 class_name[name_len-1] = '\0'; 1489 1490 computed_jsum = jsum(computed_jsum, class_name, (const int)name_len - 1); 1491 1492 // Got a class name - load it. 1493 TempNewSymbol class_name_symbol = SymbolTable::new_symbol(class_name, THREAD); 1494 guarantee(!HAS_PENDING_EXCEPTION, "Exception creating a symbol."); 1495 klassOop klass = SystemDictionary::resolve_or_null(class_name_symbol, 1496 THREAD); 1497 guarantee(!HAS_PENDING_EXCEPTION, "Exception resolving a class."); 1498 if (klass != NULL) { 1499 if (PrintSharedSpaces) { 1500 tty->print_cr("Shared spaces preloaded: %s", class_name); 1501 } 1502 1503 1504 instanceKlass* ik = instanceKlass::cast(klass); 1505 1506 // Should be class load order as per -XX:+TraceClassLoadingPreorder 1507 class_promote_order->append(ik->as_klassOop()); 1508 1509 // Link the class to cause the bytecodes to be rewritten and the 1510 // cpcache to be created. The linking is done as soon as classes 1511 // are loaded in order that the related data structures (klass, 1512 // cpCache, Sting constants) are located together. 1513 1514 if (ik->get_init_state() < instanceKlass::linked) { 1515 ik->link_class(THREAD); 1516 guarantee(!(HAS_PENDING_EXCEPTION), "exception in class rewriting"); 1517 } 1518 1519 // Create String objects from string initializer symbols. 1520 1521 ik->constants()->resolve_string_constants(THREAD); 1522 1523 class_count++; 1524 } else { 1525 if (PrintSharedSpaces) { 1526 tty->cr(); 1527 tty->print_cr(" Preload failed: %s", class_name); 1528 } 1529 } 1530 file_jsum = 0; // Checksum must be on last line of file 1531 } 1532 if (computed_jsum != file_jsum) { 1533 tty->cr(); 1534 tty->print_cr("Preload failed: checksum of class list was incorrect."); 1535 exit(1); 1536 } 1537 1538 tty->print_cr("done. "); 1539 1540 if (PrintSharedSpaces) { 1541 tty->print_cr("Shared spaces: preloaded %d classes", class_count); 1542 } 1543 1544 // Rewrite and unlink classes. 1545 tty->print("Rewriting and unlinking classes ... "); 1546 // Make heap parsable 1547 ensure_parsability(false); // arg is actually don't care 1548 1549 // Link any classes which got missed. (It's not quite clear why 1550 // they got missed.) This iteration would be unsafe if we weren't 1551 // single-threaded at this point; however we can't do it on the VM 1552 // thread because it requires object allocation. 1553 LinkClassesClosure lcc(Thread::current()); 1554 object_iterate(&lcc); 1555 ensure_parsability(false); // arg is actually don't care 1556 tty->print_cr("done. "); 1557 1558 // Create and dump the shared spaces. 1559 jint err = CompactingPermGenGen::dump_shared(class_promote_order, THREAD); 1560 if (err != JNI_OK) { 1561 fatal("Dumping shared spaces failed."); 1562 } 1563 1564 } else { 1565 char errmsg[JVM_MAXPATHLEN]; 1566 os::lasterror(errmsg, JVM_MAXPATHLEN); 1567 tty->print_cr("Loading classlist failed: %s", errmsg); 1568 exit(1); 1569 } 1570 1571 // Since various initialization steps have been undone by this process, 1572 // it is not reasonable to continue running a java process. 1573 exit(0); 1574 }