1 /* 2 * Copyright (c) 2012, 2013, 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/bytecodeAssembler.hpp" 27 #include "classfile/defaultMethods.hpp" 28 #include "classfile/symbolTable.hpp" 29 #include "memory/allocation.hpp" 30 #include "memory/metadataFactory.hpp" 31 #include "memory/resourceArea.hpp" 32 #include "runtime/signature.hpp" 33 #include "runtime/thread.hpp" 34 #include "oops/instanceKlass.hpp" 35 #include "oops/klass.hpp" 36 #include "oops/method.hpp" 37 #include "utilities/accessFlags.hpp" 38 #include "utilities/exceptions.hpp" 39 #include "utilities/ostream.hpp" 40 #include "utilities/pair.hpp" 41 #include "utilities/resourceHash.hpp" 42 43 typedef enum { QUALIFIED, DISQUALIFIED } QualifiedState; 44 45 // Because we use an iterative algorithm when iterating over the type 46 // hierarchy, we can't use traditional scoped objects which automatically do 47 // cleanup in the destructor when the scope is exited. PseudoScope (and 48 // PseudoScopeMark) provides a similar functionality, but for when you want a 49 // scoped object in non-stack memory (such as in resource memory, as we do 50 // here). You've just got to remember to call 'destroy()' on the scope when 51 // leaving it (and marks have to be explicitly added). 52 class PseudoScopeMark : public ResourceObj { 53 public: 54 virtual void destroy() = 0; 55 }; 56 57 class PseudoScope : public ResourceObj { 58 private: 59 GrowableArray<PseudoScopeMark*> _marks; 60 public: 61 62 static PseudoScope* cast(void* data) { 63 return static_cast<PseudoScope*>(data); 64 } 65 66 void add_mark(PseudoScopeMark* psm) { 67 _marks.append(psm); 68 } 69 70 void destroy() { 71 for (int i = 0; i < _marks.length(); ++i) { 72 _marks.at(i)->destroy(); 73 } 74 } 75 }; 76 77 #ifndef PRODUCT 78 static void print_slot(outputStream* str, Symbol* name, Symbol* signature) { 79 ResourceMark rm; 80 str->print("%s%s", name->as_C_string(), signature->as_C_string()); 81 } 82 83 static void print_method(outputStream* str, Method* mo, bool with_class=true) { 84 ResourceMark rm; 85 if (with_class) { 86 str->print("%s.", mo->klass_name()->as_C_string()); 87 } 88 print_slot(str, mo->name(), mo->signature()); 89 } 90 #endif // ndef PRODUCT 91 92 /** 93 * Perform a depth-first iteration over the class hierarchy, applying 94 * algorithmic logic as it goes. 95 * 96 * This class is one half of the inheritance hierarchy analysis mechanism. 97 * It is meant to be used in conjunction with another class, the algorithm, 98 * which is indicated by the ALGO template parameter. This class can be 99 * paired with any algorithm class that provides the required methods. 100 * 101 * This class contains all the mechanics for iterating over the class hierarchy 102 * starting at a particular root, without recursing (thus limiting stack growth 103 * from this point). It visits each superclass (if present) and superinterface 104 * in a depth-first manner, with callbacks to the ALGO class as each class is 105 * encountered (visit()), The algorithm can cut-off further exploration of a 106 * particular branch by returning 'false' from a visit() call. 107 * 108 * The ALGO class, must provide a visit() method, which each of which will be 109 * called once for each node in the inheritance tree during the iteration. In 110 * addition, it can provide a memory block via new_node_data(InstanceKlass*), 111 * which it can use for node-specific storage (and access via the 112 * current_data() and data_at_depth(int) methods). 113 * 114 * Bare minimum needed to be an ALGO class: 115 * class Algo : public HierarchyVisitor<Algo> { 116 * void* new_node_data(InstanceKlass* cls) { return NULL; } 117 * void free_node_data(void* data) { return; } 118 * bool visit() { return true; } 119 * }; 120 */ 121 template <class ALGO> 122 class HierarchyVisitor : StackObj { 123 private: 124 125 class Node : public ResourceObj { 126 public: 127 InstanceKlass* _class; 128 bool _super_was_visited; 129 int _interface_index; 130 void* _algorithm_data; 131 132 Node(InstanceKlass* cls, void* data, bool visit_super) 133 : _class(cls), _super_was_visited(!visit_super), 134 _interface_index(0), _algorithm_data(data) {} 135 136 int number_of_interfaces() { return _class->local_interfaces()->length(); } 137 int interface_index() { return _interface_index; } 138 void set_super_visited() { _super_was_visited = true; } 139 void increment_visited_interface() { ++_interface_index; } 140 void set_all_interfaces_visited() { 141 _interface_index = number_of_interfaces(); 142 } 143 bool has_visited_super() { return _super_was_visited; } 144 bool has_visited_all_interfaces() { 145 return interface_index() >= number_of_interfaces(); 146 } 147 InstanceKlass* interface_at(int index) { 148 return InstanceKlass::cast(_class->local_interfaces()->at(index)); 149 } 150 InstanceKlass* next_super() { return _class->java_super(); } 151 InstanceKlass* next_interface() { 152 return interface_at(interface_index()); 153 } 154 }; 155 156 bool _cancelled; 157 GrowableArray<Node*> _path; 158 159 Node* current_top() const { return _path.top(); } 160 bool has_more_nodes() const { return !_path.is_empty(); } 161 void push(InstanceKlass* cls, void* data) { 162 assert(cls != NULL, "Requires a valid instance class"); 163 Node* node = new Node(cls, data, has_super(cls)); 164 _path.push(node); 165 } 166 void pop() { _path.pop(); } 167 168 void reset_iteration() { 169 _cancelled = false; 170 _path.clear(); 171 } 172 bool is_cancelled() const { return _cancelled; } 173 174 // This code used to skip interface classes because their only 175 // superclass was j.l.Object which would be also covered by class 176 // superclass hierarchy walks. Now that the starting point can be 177 // an interface, we must ensure we catch j.l.Object as the super. 178 static bool has_super(InstanceKlass* cls) { 179 return cls->super() != NULL; 180 } 181 182 Node* node_at_depth(int i) const { 183 return (i >= _path.length()) ? NULL : _path.at(_path.length() - i - 1); 184 } 185 186 protected: 187 188 // Accessors available to the algorithm 189 int current_depth() const { return _path.length() - 1; } 190 191 InstanceKlass* class_at_depth(int i) { 192 Node* n = node_at_depth(i); 193 return n == NULL ? NULL : n->_class; 194 } 195 InstanceKlass* current_class() { return class_at_depth(0); } 196 197 void* data_at_depth(int i) { 198 Node* n = node_at_depth(i); 199 return n == NULL ? NULL : n->_algorithm_data; 200 } 201 void* current_data() { return data_at_depth(0); } 202 203 void cancel_iteration() { _cancelled = true; } 204 205 public: 206 207 void run(InstanceKlass* root) { 208 ALGO* algo = static_cast<ALGO*>(this); 209 210 reset_iteration(); 211 212 void* algo_data = algo->new_node_data(root); 213 push(root, algo_data); 214 bool top_needs_visit = true; 215 216 do { 217 Node* top = current_top(); 218 if (top_needs_visit) { 219 if (algo->visit() == false) { 220 // algorithm does not want to continue along this path. Arrange 221 // it so that this state is immediately popped off the stack 222 top->set_super_visited(); 223 top->set_all_interfaces_visited(); 224 } 225 top_needs_visit = false; 226 } 227 228 if (top->has_visited_super() && top->has_visited_all_interfaces()) { 229 algo->free_node_data(top->_algorithm_data); 230 pop(); 231 } else { 232 InstanceKlass* next = NULL; 233 if (top->has_visited_super() == false) { 234 next = top->next_super(); 235 top->set_super_visited(); 236 } else { 237 next = top->next_interface(); 238 top->increment_visited_interface(); 239 } 240 assert(next != NULL, "Otherwise we shouldn't be here"); 241 algo_data = algo->new_node_data(next); 242 push(next, algo_data); 243 top_needs_visit = true; 244 } 245 } while (!is_cancelled() && has_more_nodes()); 246 } 247 }; 248 249 #ifndef PRODUCT 250 class PrintHierarchy : public HierarchyVisitor<PrintHierarchy> { 251 public: 252 253 bool visit() { 254 InstanceKlass* cls = current_class(); 255 streamIndentor si(tty, current_depth() * 2); 256 tty->indent().print_cr("%s", cls->name()->as_C_string()); 257 return true; 258 } 259 260 void* new_node_data(InstanceKlass* cls) { return NULL; } 261 void free_node_data(void* data) { return; } 262 }; 263 #endif // ndef PRODUCT 264 265 // Used to register InstanceKlass objects and all related metadata structures 266 // (Methods, ConstantPools) as "in-use" by the current thread so that they can't 267 // be deallocated by class redefinition while we're using them. The classes are 268 // de-registered when this goes out of scope. 269 // 270 // Once a class is registered, we need not bother with methodHandles or 271 // constantPoolHandles for it's associated metadata. 272 class KeepAliveRegistrar : public StackObj { 273 private: 274 Thread* _thread; 275 GrowableArray<ConstantPool*> _keep_alive; 276 277 public: 278 KeepAliveRegistrar(Thread* thread) : _thread(thread), _keep_alive(20) { 279 assert(thread == Thread::current(), "Must be current thread"); 280 } 281 282 ~KeepAliveRegistrar() { 283 for (int i = _keep_alive.length() - 1; i >= 0; --i) { 284 ConstantPool* cp = _keep_alive.at(i); 285 int idx = _thread->metadata_handles()->find_from_end(cp); 286 assert(idx > 0, "Must be in the list"); 287 _thread->metadata_handles()->remove_at(idx); 288 } 289 } 290 291 // Register a class as 'in-use' by the thread. It's fine to register a class 292 // multiple times (though perhaps inefficient) 293 void register_class(InstanceKlass* ik) { 294 ConstantPool* cp = ik->constants(); 295 _keep_alive.push(cp); 296 _thread->metadata_handles()->push(cp); 297 } 298 }; 299 300 class KeepAliveVisitor : public HierarchyVisitor<KeepAliveVisitor> { 301 private: 302 KeepAliveRegistrar* _registrar; 303 304 public: 305 KeepAliveVisitor(KeepAliveRegistrar* registrar) : _registrar(registrar) {} 306 307 void* new_node_data(InstanceKlass* cls) { return NULL; } 308 void free_node_data(void* data) { return; } 309 310 bool visit() { 311 _registrar->register_class(current_class()); 312 return true; 313 } 314 }; 315 316 317 // A method family contains a set of all methods that implement a single 318 // erased method. As members of the set are collected while walking over the 319 // hierarchy, they are tagged with a qualification state. The qualification 320 // state for an erased method is set to disqualified if there exists a path 321 // from the root of hierarchy to the method that contains an interleaving 322 // erased method defined in an interface. 323 324 class MethodFamily : public ResourceObj { 325 private: 326 327 GrowableArray<Pair<Method*,QualifiedState> > _members; 328 ResourceHashtable<Method*, int> _member_index; 329 330 Method* _selected_target; // Filled in later, if a unique target exists 331 Symbol* _exception_message; // If no unique target is found 332 Symbol* _exception_name; // If no unique target is found 333 334 bool contains_method(Method* method) { 335 int* lookup = _member_index.get(method); 336 return lookup != NULL; 337 } 338 339 void add_method(Method* method, QualifiedState state) { 340 Pair<Method*,QualifiedState> entry(method, state); 341 _member_index.put(method, _members.length()); 342 _members.append(entry); 343 } 344 345 void disqualify_method(Method* method) { 346 int* index = _member_index.get(method); 347 guarantee(index != NULL && *index >= 0 && *index < _members.length(), "bad index"); 348 _members.at(*index).second = DISQUALIFIED; 349 } 350 351 Symbol* generate_no_defaults_message(TRAPS) const; 352 Symbol* generate_method_message(Symbol *klass_name, Method* method, TRAPS) const; 353 Symbol* generate_conflicts_message(GrowableArray<Method*>* methods, TRAPS) const; 354 355 public: 356 357 MethodFamily() 358 : _selected_target(NULL), _exception_message(NULL), _exception_name(NULL) {} 359 360 void set_target_if_empty(Method* m) { 361 if (_selected_target == NULL && !m->is_overpass()) { 362 _selected_target = m; 363 } 364 } 365 366 void record_qualified_method(Method* m) { 367 // If the method already exists in the set as qualified, this operation is 368 // redundant. If it already exists as disqualified, then we leave it as 369 // disqualfied. Thus we only add to the set if it's not already in the 370 // set. 371 if (!contains_method(m)) { 372 add_method(m, QUALIFIED); 373 } 374 } 375 376 void record_disqualified_method(Method* m) { 377 // If not in the set, add it as disqualified. If it's already in the set, 378 // then set the state to disqualified no matter what the previous state was. 379 if (!contains_method(m)) { 380 add_method(m, DISQUALIFIED); 381 } else { 382 disqualify_method(m); 383 } 384 } 385 386 bool has_target() const { return _selected_target != NULL; } 387 bool throws_exception() { return _exception_message != NULL; } 388 389 Method* get_selected_target() { return _selected_target; } 390 Symbol* get_exception_message() { return _exception_message; } 391 Symbol* get_exception_name() { return _exception_name; } 392 393 // Either sets the target or the exception error message 394 void determine_target(InstanceKlass* root, TRAPS) { 395 if (has_target() || throws_exception()) { 396 return; 397 } 398 399 // Qualified methods are maximally-specific methods 400 // These include public, instance concrete (=default) and abstract methods 401 GrowableArray<Method*> qualified_methods; 402 int num_defaults = 0; 403 int default_index = -1; 404 int qualified_index = -1; 405 for (int i = 0; i < _members.length(); ++i) { 406 Pair<Method*,QualifiedState> entry = _members.at(i); 407 if (entry.second == QUALIFIED) { 408 qualified_methods.append(entry.first); 409 qualified_index++; 410 if (entry.first->is_default_method()) { 411 num_defaults++; 412 default_index = qualified_index; 413 414 } 415 } 416 } 417 418 if (num_defaults == 0) { 419 if (qualified_methods.length() == 0) { 420 _exception_message = generate_no_defaults_message(CHECK); 421 } else { 422 assert(root != NULL, "Null root class"); 423 _exception_message = generate_method_message(root->name(), qualified_methods.at(0), CHECK); 424 } 425 _exception_name = vmSymbols::java_lang_AbstractMethodError(); 426 // If only one qualified method is default, select that 427 } else if (num_defaults == 1) { 428 _selected_target = qualified_methods.at(default_index); 429 } else if (num_defaults > 1) { 430 _exception_message = generate_conflicts_message(&qualified_methods,CHECK); 431 _exception_name = vmSymbols::java_lang_IncompatibleClassChangeError(); 432 if (TraceDefaultMethods) { 433 _exception_message->print_value_on(tty); 434 tty->print_cr(""); 435 } 436 } 437 } 438 439 bool contains_signature(Symbol* query) { 440 for (int i = 0; i < _members.length(); ++i) { 441 if (query == _members.at(i).first->signature()) { 442 return true; 443 } 444 } 445 return false; 446 } 447 448 #ifndef PRODUCT 449 void print_sig_on(outputStream* str, Symbol* signature, int indent) const { 450 streamIndentor si(str, indent * 2); 451 452 str->indent().print_cr("Logical Method %s:", signature->as_C_string()); 453 454 streamIndentor si2(str); 455 for (int i = 0; i < _members.length(); ++i) { 456 str->indent(); 457 print_method(str, _members.at(i).first); 458 if (_members.at(i).second == DISQUALIFIED) { 459 str->print(" (disqualified)"); 460 } 461 str->print_cr(""); 462 } 463 464 if (_selected_target != NULL) { 465 print_selected(str, 1); 466 } 467 } 468 469 void print_selected(outputStream* str, int indent) const { 470 assert(has_target(), "Should be called otherwise"); 471 streamIndentor si(str, indent * 2); 472 str->indent().print("Selected method: "); 473 print_method(str, _selected_target); 474 Klass* method_holder = _selected_target->method_holder(); 475 if (!method_holder->is_interface()) { 476 tty->print(" : in superclass"); 477 } 478 str->print_cr(""); 479 } 480 481 void print_exception(outputStream* str, int indent) { 482 assert(throws_exception(), "Should be called otherwise"); 483 assert(_exception_name != NULL, "exception_name should be set"); 484 streamIndentor si(str, indent * 2); 485 str->indent().print_cr("%s: %s", _exception_name->as_C_string(), _exception_message->as_C_string()); 486 } 487 #endif // ndef PRODUCT 488 }; 489 490 Symbol* MethodFamily::generate_no_defaults_message(TRAPS) const { 491 return SymbolTable::new_symbol("No qualifying defaults found", CHECK_NULL); 492 } 493 494 Symbol* MethodFamily::generate_method_message(Symbol *klass_name, Method* method, TRAPS) const { 495 stringStream ss; 496 ss.print("Method "); 497 Symbol* name = method->name(); 498 Symbol* signature = method->signature(); 499 ss.write((const char*)klass_name->bytes(), klass_name->utf8_length()); 500 ss.print("."); 501 ss.write((const char*)name->bytes(), name->utf8_length()); 502 ss.write((const char*)signature->bytes(), signature->utf8_length()); 503 ss.print(" is abstract"); 504 return SymbolTable::new_symbol(ss.base(), (int)ss.size(), CHECK_NULL); 505 } 506 507 Symbol* MethodFamily::generate_conflicts_message(GrowableArray<Method*>* methods, TRAPS) const { 508 stringStream ss; 509 ss.print("Conflicting default methods:"); 510 for (int i = 0; i < methods->length(); ++i) { 511 Method* method = methods->at(i); 512 Symbol* klass = method->klass_name(); 513 Symbol* name = method->name(); 514 ss.print(" "); 515 ss.write((const char*)klass->bytes(), klass->utf8_length()); 516 ss.print("."); 517 ss.write((const char*)name->bytes(), name->utf8_length()); 518 } 519 return SymbolTable::new_symbol(ss.base(), (int)ss.size(), CHECK_NULL); 520 } 521 522 523 class StateRestorer; 524 525 // StatefulMethodFamily is a wrapper around a MethodFamily that maintains the 526 // qualification state during hierarchy visitation, and applies that state 527 // when adding members to the MethodFamily 528 class StatefulMethodFamily : public ResourceObj { 529 friend class StateRestorer; 530 private: 531 QualifiedState _qualification_state; 532 533 void set_qualification_state(QualifiedState state) { 534 _qualification_state = state; 535 } 536 537 protected: 538 MethodFamily* _method_family; 539 540 public: 541 StatefulMethodFamily() { 542 _method_family = new MethodFamily(); 543 _qualification_state = QUALIFIED; 544 } 545 546 StatefulMethodFamily(MethodFamily* mf) { 547 _method_family = mf; 548 _qualification_state = QUALIFIED; 549 } 550 551 void set_target_if_empty(Method* m) { _method_family->set_target_if_empty(m); } 552 553 MethodFamily* get_method_family() { return _method_family; } 554 555 StateRestorer* record_method_and_dq_further(Method* mo); 556 }; 557 558 class StateRestorer : public PseudoScopeMark { 559 private: 560 StatefulMethodFamily* _method; 561 QualifiedState _state_to_restore; 562 public: 563 StateRestorer(StatefulMethodFamily* dm, QualifiedState state) 564 : _method(dm), _state_to_restore(state) {} 565 ~StateRestorer() { destroy(); } 566 void restore_state() { _method->set_qualification_state(_state_to_restore); } 567 virtual void destroy() { restore_state(); } 568 }; 569 570 StateRestorer* StatefulMethodFamily::record_method_and_dq_further(Method* mo) { 571 StateRestorer* mark = new StateRestorer(this, _qualification_state); 572 if (_qualification_state == QUALIFIED) { 573 _method_family->record_qualified_method(mo); 574 } else { 575 _method_family->record_disqualified_method(mo); 576 } 577 // Everything found "above"??? this method in the hierarchy walk is set to 578 // disqualified 579 set_qualification_state(DISQUALIFIED); 580 return mark; 581 } 582 583 // Represents a location corresponding to a vtable slot for methods that 584 // neither the class nor any of it's ancestors provide an implementaion. 585 // Default methods may be present to fill this slot. 586 class EmptyVtableSlot : public ResourceObj { 587 private: 588 Symbol* _name; 589 Symbol* _signature; 590 int _size_of_parameters; 591 MethodFamily* _binding; 592 593 public: 594 EmptyVtableSlot(Method* method) 595 : _name(method->name()), _signature(method->signature()), 596 _size_of_parameters(method->size_of_parameters()), _binding(NULL) {} 597 598 Symbol* name() const { return _name; } 599 Symbol* signature() const { return _signature; } 600 int size_of_parameters() const { return _size_of_parameters; } 601 602 void bind_family(MethodFamily* lm) { _binding = lm; } 603 bool is_bound() { return _binding != NULL; } 604 MethodFamily* get_binding() { return _binding; } 605 606 #ifndef PRODUCT 607 void print_on(outputStream* str) const { 608 print_slot(str, name(), signature()); 609 } 610 #endif // ndef PRODUCT 611 }; 612 613 static bool already_in_vtable_slots(GrowableArray<EmptyVtableSlot*>* slots, Method* m) { 614 bool found = false; 615 for (int j = 0; j < slots->length(); ++j) { 616 if (slots->at(j)->name() == m->name() && 617 slots->at(j)->signature() == m->signature() ) { 618 found = true; 619 break; 620 } 621 } 622 return found; 623 } 624 625 static GrowableArray<EmptyVtableSlot*>* find_empty_vtable_slots( 626 InstanceKlass* klass, GrowableArray<Method*>* mirandas, TRAPS) { 627 628 assert(klass != NULL, "Must be valid class"); 629 630 GrowableArray<EmptyVtableSlot*>* slots = new GrowableArray<EmptyVtableSlot*>(); 631 632 // All miranda methods are obvious candidates 633 for (int i = 0; i < mirandas->length(); ++i) { 634 Method* m = mirandas->at(i); 635 if (!already_in_vtable_slots(slots, m)) { 636 slots->append(new EmptyVtableSlot(m)); 637 } 638 } 639 640 // Also any overpasses in our superclasses, that we haven't implemented. 641 // (can't use the vtable because it is not guaranteed to be initialized yet) 642 InstanceKlass* super = klass->java_super(); 643 while (super != NULL) { 644 for (int i = 0; i < super->methods()->length(); ++i) { 645 Method* m = super->methods()->at(i); 646 if (m->is_overpass() || m->is_static()) { 647 // m is a method that would have been a miranda if not for the 648 // default method processing that occurred on behalf of our superclass, 649 // so it's a method we want to re-examine in this new context. That is, 650 // unless we have a real implementation of it in the current class. 651 Method* impl = klass->lookup_method(m->name(), m->signature()); 652 if (impl == NULL || impl->is_overpass() || impl->is_static()) { 653 if (!already_in_vtable_slots(slots, m)) { 654 slots->append(new EmptyVtableSlot(m)); 655 } 656 } 657 } 658 } 659 660 // also any default methods in our superclasses 661 if (super->default_methods() != NULL) { 662 for (int i = 0; i < super->default_methods()->length(); ++i) { 663 Method* m = super->default_methods()->at(i); 664 // m is a method that would have been a miranda if not for the 665 // default method processing that occurred on behalf of our superclass, 666 // so it's a method we want to re-examine in this new context. That is, 667 // unless we have a real implementation of it in the current class. 668 Method* impl = klass->lookup_method(m->name(), m->signature()); 669 if (impl == NULL || impl->is_overpass() || impl->is_static()) { 670 if (!already_in_vtable_slots(slots, m)) { 671 slots->append(new EmptyVtableSlot(m)); 672 } 673 } 674 } 675 } 676 super = super->java_super(); 677 } 678 679 #ifndef PRODUCT 680 if (TraceDefaultMethods) { 681 tty->print_cr("Slots that need filling:"); 682 streamIndentor si(tty); 683 for (int i = 0; i < slots->length(); ++i) { 684 tty->indent(); 685 slots->at(i)->print_on(tty); 686 tty->print_cr(""); 687 } 688 } 689 #endif // ndef PRODUCT 690 return slots; 691 } 692 693 // Iterates over the superinterface type hierarchy looking for all methods 694 // with a specific erased signature. 695 class FindMethodsByErasedSig : public HierarchyVisitor<FindMethodsByErasedSig> { 696 private: 697 // Context data 698 Symbol* _method_name; 699 Symbol* _method_signature; 700 StatefulMethodFamily* _family; 701 702 public: 703 FindMethodsByErasedSig(Symbol* name, Symbol* signature) : 704 _method_name(name), _method_signature(signature), 705 _family(NULL) {} 706 707 void get_discovered_family(MethodFamily** family) { 708 if (_family != NULL) { 709 *family = _family->get_method_family(); 710 } else { 711 *family = NULL; 712 } 713 } 714 715 void* new_node_data(InstanceKlass* cls) { return new PseudoScope(); } 716 void free_node_data(void* node_data) { 717 PseudoScope::cast(node_data)->destroy(); 718 } 719 720 // Find all methods on this hierarchy that match this 721 // method's erased (name, signature) 722 bool visit() { 723 PseudoScope* scope = PseudoScope::cast(current_data()); 724 InstanceKlass* iklass = current_class(); 725 726 Method* m = iklass->find_method(_method_name, _method_signature); 727 // private interface methods are not candidates for default methods 728 // invokespecial to private interface methods doesn't use default method logic 729 // The overpasses are your supertypes' errors, we do not include them 730 // future: take access controls into account for superclass methods 731 if (m != NULL && !m->is_static() && !m->is_overpass() && 732 (!iklass->is_interface() || m->is_public())) { 733 if (_family == NULL) { 734 _family = new StatefulMethodFamily(); 735 } 736 737 if (iklass->is_interface()) { 738 StateRestorer* restorer = _family->record_method_and_dq_further(m); 739 scope->add_mark(restorer); 740 } else { 741 // This is the rule that methods in classes "win" (bad word) over 742 // methods in interfaces. This works because of single inheritance 743 _family->set_target_if_empty(m); 744 } 745 } 746 return true; 747 } 748 749 }; 750 751 752 753 static void create_defaults_and_exceptions( 754 GrowableArray<EmptyVtableSlot*>* slots, InstanceKlass* klass, TRAPS); 755 756 static void generate_erased_defaults( 757 InstanceKlass* klass, GrowableArray<EmptyVtableSlot*>* empty_slots, 758 EmptyVtableSlot* slot, TRAPS) { 759 760 // sets up a set of methods with the same exact erased signature 761 FindMethodsByErasedSig visitor(slot->name(), slot->signature()); 762 visitor.run(klass); 763 764 MethodFamily* family; 765 visitor.get_discovered_family(&family); 766 if (family != NULL) { 767 family->determine_target(klass, CHECK); 768 slot->bind_family(family); 769 } 770 } 771 772 static void merge_in_new_methods(InstanceKlass* klass, 773 GrowableArray<Method*>* new_methods, TRAPS); 774 static void create_default_methods( InstanceKlass* klass, 775 GrowableArray<Method*>* new_methods, TRAPS); 776 777 // This is the guts of the default methods implementation. This is called just 778 // after the classfile has been parsed if some ancestor has default methods. 779 // 780 // First if finds any name/signature slots that need any implementation (either 781 // because they are miranda or a superclass's implementation is an overpass 782 // itself). For each slot, iterate over the hierarchy, to see if they contain a 783 // signature that matches the slot we are looking at. 784 // 785 // For each slot filled, we generate an overpass method that either calls the 786 // unique default method candidate using invokespecial, or throws an exception 787 // (in the case of no default method candidates, or more than one valid 788 // candidate). These methods are then added to the class's method list. 789 // The JVM does not create bridges nor handle generic signatures here. 790 void DefaultMethods::generate_default_methods( 791 InstanceKlass* klass, GrowableArray<Method*>* mirandas, TRAPS) { 792 793 // This resource mark is the bound for all memory allocation that takes 794 // place during default method processing. After this goes out of scope, 795 // all (Resource) objects' memory will be reclaimed. Be careful if adding an 796 // embedded resource mark under here as that memory can't be used outside 797 // whatever scope it's in. 798 ResourceMark rm(THREAD); 799 800 // Keep entire hierarchy alive for the duration of the computation 801 KeepAliveRegistrar keepAlive(THREAD); 802 KeepAliveVisitor loadKeepAlive(&keepAlive); 803 loadKeepAlive.run(klass); 804 805 #ifndef PRODUCT 806 if (TraceDefaultMethods) { 807 ResourceMark rm; // be careful with these! 808 tty->print_cr("%s %s requires default method processing", 809 klass->is_interface() ? "Interface" : "Class", 810 klass->name()->as_klass_external_name()); 811 PrintHierarchy printer; 812 printer.run(klass); 813 } 814 #endif // ndef PRODUCT 815 816 GrowableArray<EmptyVtableSlot*>* empty_slots = 817 find_empty_vtable_slots(klass, mirandas, CHECK); 818 819 for (int i = 0; i < empty_slots->length(); ++i) { 820 EmptyVtableSlot* slot = empty_slots->at(i); 821 #ifndef PRODUCT 822 if (TraceDefaultMethods) { 823 streamIndentor si(tty, 2); 824 tty->indent().print("Looking for default methods for slot "); 825 slot->print_on(tty); 826 tty->print_cr(""); 827 } 828 #endif // ndef PRODUCT 829 830 generate_erased_defaults(klass, empty_slots, slot, CHECK); 831 } 832 #ifndef PRODUCT 833 if (TraceDefaultMethods) { 834 tty->print_cr("Creating defaults and overpasses..."); 835 } 836 #endif // ndef PRODUCT 837 838 create_defaults_and_exceptions(empty_slots, klass, CHECK); 839 840 #ifndef PRODUCT 841 if (TraceDefaultMethods) { 842 tty->print_cr("Default method processing complete"); 843 } 844 #endif // ndef PRODUCT 845 } 846 847 static int assemble_method_error( 848 BytecodeConstantPool* cp, BytecodeBuffer* buffer, Symbol* errorName, Symbol* message, TRAPS) { 849 850 Symbol* init = vmSymbols::object_initializer_name(); 851 Symbol* sig = vmSymbols::string_void_signature(); 852 853 BytecodeAssembler assem(buffer, cp); 854 855 assem._new(errorName); 856 assem.dup(); 857 assem.load_string(message); 858 assem.invokespecial(errorName, init, sig); 859 assem.athrow(); 860 861 return 3; // max stack size: [ exception, exception, string ] 862 } 863 864 static Method* new_method( 865 BytecodeConstantPool* cp, BytecodeBuffer* bytecodes, Symbol* name, 866 Symbol* sig, AccessFlags flags, int max_stack, int params, 867 ConstMethod::MethodType mt, TRAPS) { 868 869 address code_start = 0; 870 int code_length = 0; 871 InlineTableSizes sizes; 872 873 if (bytecodes != NULL && bytecodes->length() > 0) { 874 code_start = static_cast<address>(bytecodes->adr_at(0)); 875 code_length = bytecodes->length(); 876 } 877 878 Method* m = Method::allocate(cp->pool_holder()->class_loader_data(), 879 code_length, flags, &sizes, 880 mt, CHECK_NULL); 881 882 m->set_constants(NULL); // This will get filled in later 883 m->set_name_index(cp->utf8(name)); 884 m->set_signature_index(cp->utf8(sig)); 885 #ifdef CC_INTERP 886 ResultTypeFinder rtf(sig); 887 m->set_result_index(rtf.type()); 888 #endif 889 m->set_size_of_parameters(params); 890 m->set_max_stack(max_stack); 891 m->set_max_locals(params); 892 m->constMethod()->set_stackmap_data(NULL); 893 m->set_code(code_start); 894 895 return m; 896 } 897 898 static void switchover_constant_pool(BytecodeConstantPool* bpool, 899 InstanceKlass* klass, GrowableArray<Method*>* new_methods, TRAPS) { 900 901 if (new_methods->length() > 0) { 902 ConstantPool* cp = bpool->create_constant_pool(CHECK); 903 if (cp != klass->constants()) { 904 klass->class_loader_data()->add_to_deallocate_list(klass->constants()); 905 klass->set_constants(cp); 906 cp->set_pool_holder(klass); 907 908 for (int i = 0; i < new_methods->length(); ++i) { 909 new_methods->at(i)->set_constants(cp); 910 } 911 for (int i = 0; i < klass->methods()->length(); ++i) { 912 Method* mo = klass->methods()->at(i); 913 mo->set_constants(cp); 914 } 915 } 916 } 917 } 918 919 // Create default_methods list for the current class. 920 // With the VM only processing erased signatures, the VM only 921 // creates an overpass in a conflict case or a case with no candidates. 922 // This allows virtual methods to override the overpass, but ensures 923 // that a local method search will find the exception rather than an abstract 924 // or default method that is not a valid candidate. 925 static void create_defaults_and_exceptions( 926 GrowableArray<EmptyVtableSlot*>* slots, 927 InstanceKlass* klass, TRAPS) { 928 929 GrowableArray<Method*> overpasses; 930 GrowableArray<Method*> defaults; 931 BytecodeConstantPool bpool(klass->constants()); 932 933 for (int i = 0; i < slots->length(); ++i) { 934 EmptyVtableSlot* slot = slots->at(i); 935 936 if (slot->is_bound()) { 937 MethodFamily* method = slot->get_binding(); 938 BytecodeBuffer buffer; 939 940 #ifndef PRODUCT 941 if (TraceDefaultMethods) { 942 tty->print("for slot: "); 943 slot->print_on(tty); 944 tty->print_cr(""); 945 if (method->has_target()) { 946 method->print_selected(tty, 1); 947 } else if (method->throws_exception()) { 948 method->print_exception(tty, 1); 949 } 950 } 951 #endif // ndef PRODUCT 952 953 if (method->has_target()) { 954 Method* selected = method->get_selected_target(); 955 if (selected->method_holder()->is_interface()) { 956 defaults.push(selected); 957 } 958 } else if (method->throws_exception()) { 959 int max_stack = assemble_method_error(&bpool, &buffer, 960 method->get_exception_name(), method->get_exception_message(), CHECK); 961 AccessFlags flags = accessFlags_from( 962 JVM_ACC_PUBLIC | JVM_ACC_SYNTHETIC | JVM_ACC_BRIDGE); 963 Method* m = new_method(&bpool, &buffer, slot->name(), slot->signature(), 964 flags, max_stack, slot->size_of_parameters(), 965 ConstMethod::OVERPASS, CHECK); 966 // We push to the methods list: 967 // overpass methods which are exception throwing methods 968 if (m != NULL) { 969 overpasses.push(m); 970 } 971 } 972 } 973 } 974 975 #ifndef PRODUCT 976 if (TraceDefaultMethods) { 977 tty->print_cr("Created %d overpass methods", overpasses.length()); 978 tty->print_cr("Created %d default methods", defaults.length()); 979 } 980 #endif // ndef PRODUCT 981 982 if (overpasses.length() > 0) { 983 switchover_constant_pool(&bpool, klass, &overpasses, CHECK); 984 merge_in_new_methods(klass, &overpasses, CHECK); 985 } 986 if (defaults.length() > 0) { 987 create_default_methods(klass, &defaults, CHECK); 988 } 989 } 990 991 static void create_default_methods( InstanceKlass* klass, 992 GrowableArray<Method*>* new_methods, TRAPS) { 993 994 int new_size = new_methods->length(); 995 Array<Method*>* total_default_methods = MetadataFactory::new_array<Method*>( 996 klass->class_loader_data(), new_size, NULL, CHECK); 997 for (int index = 0; index < new_size; index++ ) { 998 total_default_methods->at_put(index, new_methods->at(index)); 999 } 1000 Method::sort_methods(total_default_methods, false, false); 1001 1002 klass->set_default_methods(total_default_methods); 1003 } 1004 1005 static void sort_methods(GrowableArray<Method*>* methods) { 1006 // Note that this must sort using the same key as is used for sorting 1007 // methods in InstanceKlass. 1008 bool sorted = true; 1009 for (int i = methods->length() - 1; i > 0; --i) { 1010 for (int j = 0; j < i; ++j) { 1011 Method* m1 = methods->at(j); 1012 Method* m2 = methods->at(j + 1); 1013 if ((uintptr_t)m1->name() > (uintptr_t)m2->name()) { 1014 methods->at_put(j, m2); 1015 methods->at_put(j + 1, m1); 1016 sorted = false; 1017 } 1018 } 1019 if (sorted) break; 1020 sorted = true; 1021 } 1022 #ifdef ASSERT 1023 uintptr_t prev = 0; 1024 for (int i = 0; i < methods->length(); ++i) { 1025 Method* mh = methods->at(i); 1026 uintptr_t nv = (uintptr_t)mh->name(); 1027 assert(nv >= prev, "Incorrect overpass method ordering"); 1028 prev = nv; 1029 } 1030 #endif 1031 } 1032 1033 static void merge_in_new_methods(InstanceKlass* klass, 1034 GrowableArray<Method*>* new_methods, TRAPS) { 1035 1036 enum { ANNOTATIONS, PARAMETERS, DEFAULTS, NUM_ARRAYS }; 1037 1038 Array<Method*>* original_methods = klass->methods(); 1039 Array<int>* original_ordering = klass->method_ordering(); 1040 Array<int>* merged_ordering = Universe::the_empty_int_array(); 1041 1042 int new_size = klass->methods()->length() + new_methods->length(); 1043 1044 Array<Method*>* merged_methods = MetadataFactory::new_array<Method*>( 1045 klass->class_loader_data(), new_size, NULL, CHECK); 1046 1047 if (original_ordering != NULL && original_ordering->length() > 0) { 1048 merged_ordering = MetadataFactory::new_array<int>( 1049 klass->class_loader_data(), new_size, CHECK); 1050 } 1051 int method_order_index = klass->methods()->length(); 1052 1053 sort_methods(new_methods); 1054 1055 // Perform grand merge of existing methods and new methods 1056 int orig_idx = 0; 1057 int new_idx = 0; 1058 1059 for (int i = 0; i < new_size; ++i) { 1060 Method* orig_method = NULL; 1061 Method* new_method = NULL; 1062 if (orig_idx < original_methods->length()) { 1063 orig_method = original_methods->at(orig_idx); 1064 } 1065 if (new_idx < new_methods->length()) { 1066 new_method = new_methods->at(new_idx); 1067 } 1068 1069 if (orig_method != NULL && 1070 (new_method == NULL || orig_method->name() < new_method->name())) { 1071 merged_methods->at_put(i, orig_method); 1072 original_methods->at_put(orig_idx, NULL); 1073 if (merged_ordering->length() > 0) { 1074 merged_ordering->at_put(i, original_ordering->at(orig_idx)); 1075 } 1076 ++orig_idx; 1077 } else { 1078 merged_methods->at_put(i, new_method); 1079 if (merged_ordering->length() > 0) { 1080 merged_ordering->at_put(i, method_order_index++); 1081 } 1082 ++new_idx; 1083 } 1084 // update idnum for new location 1085 merged_methods->at(i)->set_method_idnum(i); 1086 } 1087 1088 // Verify correct order 1089 #ifdef ASSERT 1090 uintptr_t prev = 0; 1091 for (int i = 0; i < merged_methods->length(); ++i) { 1092 Method* mo = merged_methods->at(i); 1093 uintptr_t nv = (uintptr_t)mo->name(); 1094 assert(nv >= prev, "Incorrect method ordering"); 1095 prev = nv; 1096 } 1097 #endif 1098 1099 // Replace klass methods with new merged lists 1100 klass->set_methods(merged_methods); 1101 klass->set_initial_method_idnum(new_size); 1102 1103 ClassLoaderData* cld = klass->class_loader_data(); 1104 if (original_methods ->length() > 0) { 1105 MetadataFactory::free_array(cld, original_methods); 1106 } 1107 if (original_ordering->length() > 0) { 1108 klass->set_method_ordering(merged_ordering); 1109 MetadataFactory::free_array(cld, original_ordering); 1110 } 1111 }