Thu, 03 Oct 2013 16:38:21 +0400
Merge
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 */
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"
43 typedef enum { QUALIFIED, DISQUALIFIED } QualifiedState;
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 };
57 class PseudoScope : public ResourceObj {
58 private:
59 GrowableArray<PseudoScopeMark*> _marks;
60 public:
62 static PseudoScope* cast(void* data) {
63 return static_cast<PseudoScope*>(data);
64 }
66 void add_mark(PseudoScopeMark* psm) {
67 _marks.append(psm);
68 }
70 void destroy() {
71 for (int i = 0; i < _marks.length(); ++i) {
72 _marks.at(i)->destroy();
73 }
74 }
75 };
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 }
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
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:
125 class Node : public ResourceObj {
126 public:
127 InstanceKlass* _class;
128 bool _super_was_visited;
129 int _interface_index;
130 void* _algorithm_data;
132 Node(InstanceKlass* cls, void* data, bool visit_super)
133 : _class(cls), _super_was_visited(!visit_super),
134 _interface_index(0), _algorithm_data(data) {}
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 };
156 bool _cancelled;
157 GrowableArray<Node*> _path;
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(); }
168 void reset_iteration() {
169 _cancelled = false;
170 _path.clear();
171 }
172 bool is_cancelled() const { return _cancelled; }
174 static bool has_super(InstanceKlass* cls) {
175 return cls->super() != NULL && !cls->is_interface();
176 }
178 Node* node_at_depth(int i) const {
179 return (i >= _path.length()) ? NULL : _path.at(_path.length() - i - 1);
180 }
182 protected:
184 // Accessors available to the algorithm
185 int current_depth() const { return _path.length() - 1; }
187 InstanceKlass* class_at_depth(int i) {
188 Node* n = node_at_depth(i);
189 return n == NULL ? NULL : n->_class;
190 }
191 InstanceKlass* current_class() { return class_at_depth(0); }
193 void* data_at_depth(int i) {
194 Node* n = node_at_depth(i);
195 return n == NULL ? NULL : n->_algorithm_data;
196 }
197 void* current_data() { return data_at_depth(0); }
199 void cancel_iteration() { _cancelled = true; }
201 public:
203 void run(InstanceKlass* root) {
204 ALGO* algo = static_cast<ALGO*>(this);
206 reset_iteration();
208 void* algo_data = algo->new_node_data(root);
209 push(root, algo_data);
210 bool top_needs_visit = true;
212 do {
213 Node* top = current_top();
214 if (top_needs_visit) {
215 if (algo->visit() == false) {
216 // algorithm does not want to continue along this path. Arrange
217 // it so that this state is immediately popped off the stack
218 top->set_super_visited();
219 top->set_all_interfaces_visited();
220 }
221 top_needs_visit = false;
222 }
224 if (top->has_visited_super() && top->has_visited_all_interfaces()) {
225 algo->free_node_data(top->_algorithm_data);
226 pop();
227 } else {
228 InstanceKlass* next = NULL;
229 if (top->has_visited_super() == false) {
230 next = top->next_super();
231 top->set_super_visited();
232 } else {
233 next = top->next_interface();
234 top->increment_visited_interface();
235 }
236 assert(next != NULL, "Otherwise we shouldn't be here");
237 algo_data = algo->new_node_data(next);
238 push(next, algo_data);
239 top_needs_visit = true;
240 }
241 } while (!is_cancelled() && has_more_nodes());
242 }
243 };
245 #ifndef PRODUCT
246 class PrintHierarchy : public HierarchyVisitor<PrintHierarchy> {
247 public:
249 bool visit() {
250 InstanceKlass* cls = current_class();
251 streamIndentor si(tty, current_depth() * 2);
252 tty->indent().print_cr("%s", cls->name()->as_C_string());
253 return true;
254 }
256 void* new_node_data(InstanceKlass* cls) { return NULL; }
257 void free_node_data(void* data) { return; }
258 };
259 #endif // ndef PRODUCT
261 // Used to register InstanceKlass objects and all related metadata structures
262 // (Methods, ConstantPools) as "in-use" by the current thread so that they can't
263 // be deallocated by class redefinition while we're using them. The classes are
264 // de-registered when this goes out of scope.
265 //
266 // Once a class is registered, we need not bother with methodHandles or
267 // constantPoolHandles for it's associated metadata.
268 class KeepAliveRegistrar : public StackObj {
269 private:
270 Thread* _thread;
271 GrowableArray<ConstantPool*> _keep_alive;
273 public:
274 KeepAliveRegistrar(Thread* thread) : _thread(thread), _keep_alive(20) {
275 assert(thread == Thread::current(), "Must be current thread");
276 }
278 ~KeepAliveRegistrar() {
279 for (int i = _keep_alive.length() - 1; i >= 0; --i) {
280 ConstantPool* cp = _keep_alive.at(i);
281 int idx = _thread->metadata_handles()->find_from_end(cp);
282 assert(idx > 0, "Must be in the list");
283 _thread->metadata_handles()->remove_at(idx);
284 }
285 }
287 // Register a class as 'in-use' by the thread. It's fine to register a class
288 // multiple times (though perhaps inefficient)
289 void register_class(InstanceKlass* ik) {
290 ConstantPool* cp = ik->constants();
291 _keep_alive.push(cp);
292 _thread->metadata_handles()->push(cp);
293 }
294 };
296 class KeepAliveVisitor : public HierarchyVisitor<KeepAliveVisitor> {
297 private:
298 KeepAliveRegistrar* _registrar;
300 public:
301 KeepAliveVisitor(KeepAliveRegistrar* registrar) : _registrar(registrar) {}
303 void* new_node_data(InstanceKlass* cls) { return NULL; }
304 void free_node_data(void* data) { return; }
306 bool visit() {
307 _registrar->register_class(current_class());
308 return true;
309 }
310 };
313 // A method family contains a set of all methods that implement a single
314 // erased method. As members of the set are collected while walking over the
315 // hierarchy, they are tagged with a qualification state. The qualification
316 // state for an erased method is set to disqualified if there exists a path
317 // from the root of hierarchy to the method that contains an interleaving
318 // erased method defined in an interface.
320 class MethodFamily : public ResourceObj {
321 private:
323 GrowableArray<Pair<Method*,QualifiedState> > _members;
324 ResourceHashtable<Method*, int> _member_index;
326 Method* _selected_target; // Filled in later, if a unique target exists
327 Symbol* _exception_message; // If no unique target is found
328 Symbol* _exception_name; // If no unique target is found
330 bool contains_method(Method* method) {
331 int* lookup = _member_index.get(method);
332 return lookup != NULL;
333 }
335 void add_method(Method* method, QualifiedState state) {
336 Pair<Method*,QualifiedState> entry(method, state);
337 _member_index.put(method, _members.length());
338 _members.append(entry);
339 }
341 void disqualify_method(Method* method) {
342 int* index = _member_index.get(method);
343 guarantee(index != NULL && *index >= 0 && *index < _members.length(), "bad index");
344 _members.at(*index).second = DISQUALIFIED;
345 }
347 Symbol* generate_no_defaults_message(TRAPS) const;
348 Symbol* generate_abstract_method_message(Method* method, TRAPS) const;
349 Symbol* generate_conflicts_message(GrowableArray<Method*>* methods, TRAPS) const;
351 public:
353 MethodFamily()
354 : _selected_target(NULL), _exception_message(NULL), _exception_name(NULL) {}
356 void set_target_if_empty(Method* m) {
357 if (_selected_target == NULL && !m->is_overpass()) {
358 _selected_target = m;
359 }
360 }
362 void record_qualified_method(Method* m) {
363 // If the method already exists in the set as qualified, this operation is
364 // redundant. If it already exists as disqualified, then we leave it as
365 // disqualfied. Thus we only add to the set if it's not already in the
366 // set.
367 if (!contains_method(m)) {
368 add_method(m, QUALIFIED);
369 }
370 }
372 void record_disqualified_method(Method* m) {
373 // If not in the set, add it as disqualified. If it's already in the set,
374 // then set the state to disqualified no matter what the previous state was.
375 if (!contains_method(m)) {
376 add_method(m, DISQUALIFIED);
377 } else {
378 disqualify_method(m);
379 }
380 }
382 bool has_target() const { return _selected_target != NULL; }
383 bool throws_exception() { return _exception_message != NULL; }
385 Method* get_selected_target() { return _selected_target; }
386 Symbol* get_exception_message() { return _exception_message; }
387 Symbol* get_exception_name() { return _exception_name; }
389 // Either sets the target or the exception error message
390 void determine_target(InstanceKlass* root, TRAPS) {
391 if (has_target() || throws_exception()) {
392 return;
393 }
395 GrowableArray<Method*> qualified_methods;
396 for (int i = 0; i < _members.length(); ++i) {
397 Pair<Method*,QualifiedState> entry = _members.at(i);
398 if (entry.second == QUALIFIED) {
399 qualified_methods.append(entry.first);
400 }
401 }
403 if (qualified_methods.length() == 0) {
404 _exception_message = generate_no_defaults_message(CHECK);
405 _exception_name = vmSymbols::java_lang_AbstractMethodError();
406 } else if (qualified_methods.length() == 1) {
407 Method* method = qualified_methods.at(0);
408 if (method->is_abstract()) {
409 _exception_message = generate_abstract_method_message(method, CHECK);
410 _exception_name = vmSymbols::java_lang_AbstractMethodError();
411 } else {
412 _selected_target = qualified_methods.at(0);
413 }
414 } else {
415 _exception_message = generate_conflicts_message(&qualified_methods,CHECK);
416 _exception_name = vmSymbols::java_lang_IncompatibleClassChangeError();
417 }
419 assert((has_target() ^ throws_exception()) == 1,
420 "One and only one must be true");
421 }
423 bool contains_signature(Symbol* query) {
424 for (int i = 0; i < _members.length(); ++i) {
425 if (query == _members.at(i).first->signature()) {
426 return true;
427 }
428 }
429 return false;
430 }
432 #ifndef PRODUCT
433 void print_sig_on(outputStream* str, Symbol* signature, int indent) const {
434 streamIndentor si(str, indent * 2);
436 str->indent().print_cr("Logical Method %s:", signature->as_C_string());
438 streamIndentor si2(str);
439 for (int i = 0; i < _members.length(); ++i) {
440 str->indent();
441 print_method(str, _members.at(i).first);
442 if (_members.at(i).second == DISQUALIFIED) {
443 str->print(" (disqualified)");
444 }
445 str->print_cr("");
446 }
448 if (_selected_target != NULL) {
449 print_selected(str, 1);
450 }
451 }
453 void print_selected(outputStream* str, int indent) const {
454 assert(has_target(), "Should be called otherwise");
455 streamIndentor si(str, indent * 2);
456 str->indent().print("Selected method: ");
457 print_method(str, _selected_target);
458 Klass* method_holder = _selected_target->method_holder();
459 if (!method_holder->is_interface()) {
460 tty->print(" : in superclass");
461 }
462 str->print_cr("");
463 }
465 void print_exception(outputStream* str, int indent) {
466 assert(throws_exception(), "Should be called otherwise");
467 assert(_exception_name != NULL, "exception_name should be set");
468 streamIndentor si(str, indent * 2);
469 str->indent().print_cr("%s: %s", _exception_name->as_C_string(), _exception_message->as_C_string());
470 }
471 #endif // ndef PRODUCT
472 };
474 Symbol* MethodFamily::generate_no_defaults_message(TRAPS) const {
475 return SymbolTable::new_symbol("No qualifying defaults found", CHECK_NULL);
476 }
478 Symbol* MethodFamily::generate_abstract_method_message(Method* method, TRAPS) const {
479 Symbol* klass = method->klass_name();
480 Symbol* name = method->name();
481 Symbol* sig = method->signature();
482 stringStream ss;
483 ss.print("Method ");
484 ss.write((const char*)klass->bytes(), klass->utf8_length());
485 ss.print(".");
486 ss.write((const char*)name->bytes(), name->utf8_length());
487 ss.write((const char*)sig->bytes(), sig->utf8_length());
488 ss.print(" is abstract");
489 return SymbolTable::new_symbol(ss.base(), (int)ss.size(), CHECK_NULL);
490 }
492 Symbol* MethodFamily::generate_conflicts_message(GrowableArray<Method*>* methods, TRAPS) const {
493 stringStream ss;
494 ss.print("Conflicting default methods:");
495 for (int i = 0; i < methods->length(); ++i) {
496 Method* method = methods->at(i);
497 Symbol* klass = method->klass_name();
498 Symbol* name = method->name();
499 ss.print(" ");
500 ss.write((const char*)klass->bytes(), klass->utf8_length());
501 ss.print(".");
502 ss.write((const char*)name->bytes(), name->utf8_length());
503 }
504 return SymbolTable::new_symbol(ss.base(), (int)ss.size(), CHECK_NULL);
505 }
508 class StateRestorer;
510 // StatefulMethodFamily is a wrapper around a MethodFamily that maintains the
511 // qualification state during hierarchy visitation, and applies that state
512 // when adding members to the MethodFamily
513 class StatefulMethodFamily : public ResourceObj {
514 friend class StateRestorer;
515 private:
516 QualifiedState _qualification_state;
518 void set_qualification_state(QualifiedState state) {
519 _qualification_state = state;
520 }
522 protected:
523 MethodFamily* _method_family;
525 public:
526 StatefulMethodFamily() {
527 _method_family = new MethodFamily();
528 _qualification_state = QUALIFIED;
529 }
531 StatefulMethodFamily(MethodFamily* mf) {
532 _method_family = mf;
533 _qualification_state = QUALIFIED;
534 }
536 void set_target_if_empty(Method* m) { _method_family->set_target_if_empty(m); }
538 MethodFamily* get_method_family() { return _method_family; }
540 StateRestorer* record_method_and_dq_further(Method* mo);
541 };
543 class StateRestorer : public PseudoScopeMark {
544 private:
545 StatefulMethodFamily* _method;
546 QualifiedState _state_to_restore;
547 public:
548 StateRestorer(StatefulMethodFamily* dm, QualifiedState state)
549 : _method(dm), _state_to_restore(state) {}
550 ~StateRestorer() { destroy(); }
551 void restore_state() { _method->set_qualification_state(_state_to_restore); }
552 virtual void destroy() { restore_state(); }
553 };
555 StateRestorer* StatefulMethodFamily::record_method_and_dq_further(Method* mo) {
556 StateRestorer* mark = new StateRestorer(this, _qualification_state);
557 if (_qualification_state == QUALIFIED) {
558 _method_family->record_qualified_method(mo);
559 } else {
560 _method_family->record_disqualified_method(mo);
561 }
562 // Everything found "above"??? this method in the hierarchy walk is set to
563 // disqualified
564 set_qualification_state(DISQUALIFIED);
565 return mark;
566 }
568 // Represents a location corresponding to a vtable slot for methods that
569 // neither the class nor any of it's ancestors provide an implementaion.
570 // Default methods may be present to fill this slot.
571 class EmptyVtableSlot : public ResourceObj {
572 private:
573 Symbol* _name;
574 Symbol* _signature;
575 int _size_of_parameters;
576 MethodFamily* _binding;
578 public:
579 EmptyVtableSlot(Method* method)
580 : _name(method->name()), _signature(method->signature()),
581 _size_of_parameters(method->size_of_parameters()), _binding(NULL) {}
583 Symbol* name() const { return _name; }
584 Symbol* signature() const { return _signature; }
585 int size_of_parameters() const { return _size_of_parameters; }
587 void bind_family(MethodFamily* lm) { _binding = lm; }
588 bool is_bound() { return _binding != NULL; }
589 MethodFamily* get_binding() { return _binding; }
591 #ifndef PRODUCT
592 void print_on(outputStream* str) const {
593 print_slot(str, name(), signature());
594 }
595 #endif // ndef PRODUCT
596 };
598 static GrowableArray<EmptyVtableSlot*>* find_empty_vtable_slots(
599 InstanceKlass* klass, GrowableArray<Method*>* mirandas, TRAPS) {
601 assert(klass != NULL, "Must be valid class");
603 GrowableArray<EmptyVtableSlot*>* slots = new GrowableArray<EmptyVtableSlot*>();
605 // All miranda methods are obvious candidates
606 for (int i = 0; i < mirandas->length(); ++i) {
607 EmptyVtableSlot* slot = new EmptyVtableSlot(mirandas->at(i));
608 slots->append(slot);
609 }
611 // Also any overpasses in our superclasses, that we haven't implemented.
612 // (can't use the vtable because it is not guaranteed to be initialized yet)
613 InstanceKlass* super = klass->java_super();
614 while (super != NULL) {
615 for (int i = 0; i < super->methods()->length(); ++i) {
616 Method* m = super->methods()->at(i);
617 if (m->is_overpass()) {
618 // m is a method that would have been a miranda if not for the
619 // default method processing that occurred on behalf of our superclass,
620 // so it's a method we want to re-examine in this new context. That is,
621 // unless we have a real implementation of it in the current class.
622 Method* impl = klass->lookup_method(m->name(), m->signature());
623 if (impl == NULL || impl->is_overpass()) {
624 slots->append(new EmptyVtableSlot(m));
625 }
626 }
627 }
628 super = super->java_super();
629 }
631 #ifndef PRODUCT
632 if (TraceDefaultMethods) {
633 tty->print_cr("Slots that need filling:");
634 streamIndentor si(tty);
635 for (int i = 0; i < slots->length(); ++i) {
636 tty->indent();
637 slots->at(i)->print_on(tty);
638 tty->print_cr("");
639 }
640 }
641 #endif // ndef PRODUCT
642 return slots;
643 }
645 // Iterates over the superinterface type hierarchy looking for all methods
646 // with a specific erased signature.
647 class FindMethodsByErasedSig : public HierarchyVisitor<FindMethodsByErasedSig> {
648 private:
649 // Context data
650 Symbol* _method_name;
651 Symbol* _method_signature;
652 StatefulMethodFamily* _family;
654 public:
655 FindMethodsByErasedSig(Symbol* name, Symbol* signature) :
656 _method_name(name), _method_signature(signature),
657 _family(NULL) {}
659 void get_discovered_family(MethodFamily** family) {
660 if (_family != NULL) {
661 *family = _family->get_method_family();
662 } else {
663 *family = NULL;
664 }
665 }
667 void* new_node_data(InstanceKlass* cls) { return new PseudoScope(); }
668 void free_node_data(void* node_data) {
669 PseudoScope::cast(node_data)->destroy();
670 }
672 // Find all methods on this hierarchy that match this
673 // method's erased (name, signature)
674 bool visit() {
675 PseudoScope* scope = PseudoScope::cast(current_data());
676 InstanceKlass* iklass = current_class();
678 Method* m = iklass->find_method(_method_name, _method_signature);
679 // private interface methods are not candidates for default methods
680 // invokespecial to private interface methods doesn't use default method logic
681 // future: take access controls into account for superclass methods
682 if (m != NULL && (!iklass->is_interface() || m->is_public())) {
683 if (_family == NULL) {
684 _family = new StatefulMethodFamily();
685 }
687 if (iklass->is_interface()) {
688 StateRestorer* restorer = _family->record_method_and_dq_further(m);
689 scope->add_mark(restorer);
690 } else {
691 // This is the rule that methods in classes "win" (bad word) over
692 // methods in interfaces. This works because of single inheritance
693 _family->set_target_if_empty(m);
694 }
695 }
696 return true;
697 }
699 };
703 static void create_overpasses(
704 GrowableArray<EmptyVtableSlot*>* slots, InstanceKlass* klass, TRAPS);
706 static void generate_erased_defaults(
707 InstanceKlass* klass, GrowableArray<EmptyVtableSlot*>* empty_slots,
708 EmptyVtableSlot* slot, TRAPS) {
710 // sets up a set of methods with the same exact erased signature
711 FindMethodsByErasedSig visitor(slot->name(), slot->signature());
712 visitor.run(klass);
714 MethodFamily* family;
715 visitor.get_discovered_family(&family);
716 if (family != NULL) {
717 family->determine_target(klass, CHECK);
718 slot->bind_family(family);
719 }
720 }
722 static void merge_in_new_methods(InstanceKlass* klass,
723 GrowableArray<Method*>* new_methods, TRAPS);
725 // This is the guts of the default methods implementation. This is called just
726 // after the classfile has been parsed if some ancestor has default methods.
727 //
728 // First if finds any name/signature slots that need any implementation (either
729 // because they are miranda or a superclass's implementation is an overpass
730 // itself). For each slot, iterate over the hierarchy, to see if they contain a
731 // signature that matches the slot we are looking at.
732 //
733 // For each slot filled, we generate an overpass method that either calls the
734 // unique default method candidate using invokespecial, or throws an exception
735 // (in the case of no default method candidates, or more than one valid
736 // candidate). These methods are then added to the class's method list.
737 // The JVM does not create bridges nor handle generic signatures here.
738 void DefaultMethods::generate_default_methods(
739 InstanceKlass* klass, GrowableArray<Method*>* mirandas, TRAPS) {
741 // This resource mark is the bound for all memory allocation that takes
742 // place during default method processing. After this goes out of scope,
743 // all (Resource) objects' memory will be reclaimed. Be careful if adding an
744 // embedded resource mark under here as that memory can't be used outside
745 // whatever scope it's in.
746 ResourceMark rm(THREAD);
748 // Keep entire hierarchy alive for the duration of the computation
749 KeepAliveRegistrar keepAlive(THREAD);
750 KeepAliveVisitor loadKeepAlive(&keepAlive);
751 loadKeepAlive.run(klass);
753 #ifndef PRODUCT
754 if (TraceDefaultMethods) {
755 ResourceMark rm; // be careful with these!
756 tty->print_cr("Class %s requires default method processing",
757 klass->name()->as_klass_external_name());
758 PrintHierarchy printer;
759 printer.run(klass);
760 }
761 #endif // ndef PRODUCT
763 GrowableArray<EmptyVtableSlot*>* empty_slots =
764 find_empty_vtable_slots(klass, mirandas, CHECK);
766 for (int i = 0; i < empty_slots->length(); ++i) {
767 EmptyVtableSlot* slot = empty_slots->at(i);
768 #ifndef PRODUCT
769 if (TraceDefaultMethods) {
770 streamIndentor si(tty, 2);
771 tty->indent().print("Looking for default methods for slot ");
772 slot->print_on(tty);
773 tty->print_cr("");
774 }
775 #endif // ndef PRODUCT
777 generate_erased_defaults(klass, empty_slots, slot, CHECK);
778 }
779 #ifndef PRODUCT
780 if (TraceDefaultMethods) {
781 tty->print_cr("Creating overpasses...");
782 }
783 #endif // ndef PRODUCT
785 create_overpasses(empty_slots, klass, CHECK);
787 #ifndef PRODUCT
788 if (TraceDefaultMethods) {
789 tty->print_cr("Default method processing complete");
790 }
791 #endif // ndef PRODUCT
792 }
796 #ifdef ASSERT
797 // Return true is broad type is a covariant return of narrow type
798 static bool covariant_return_type(BasicType narrow, BasicType broad) {
799 if (narrow == broad) {
800 return true;
801 }
802 if (broad == T_OBJECT) {
803 return true;
804 }
805 return false;
806 }
807 #endif
809 static int assemble_redirect(
810 BytecodeConstantPool* cp, BytecodeBuffer* buffer,
811 Symbol* incoming, Method* target, TRAPS) {
813 BytecodeAssembler assem(buffer, cp);
815 SignatureStream in(incoming, true);
816 SignatureStream out(target->signature(), true);
817 u2 parameter_count = 0;
819 assem.aload(parameter_count++); // load 'this'
821 while (!in.at_return_type()) {
822 assert(!out.at_return_type(), "Parameter counts do not match");
823 BasicType bt = in.type();
824 assert(out.type() == bt, "Parameter types are not compatible");
825 assem.load(bt, parameter_count);
826 if (in.is_object() && in.as_symbol(THREAD) != out.as_symbol(THREAD)) {
827 assem.checkcast(out.as_symbol(THREAD));
828 } else if (bt == T_LONG || bt == T_DOUBLE) {
829 ++parameter_count; // longs and doubles use two slots
830 }
831 ++parameter_count;
832 in.next();
833 out.next();
834 }
835 assert(out.at_return_type(), "Parameter counts do not match");
836 assert(covariant_return_type(out.type(), in.type()), "Return types are not compatible");
838 if (parameter_count == 1 && (in.type() == T_LONG || in.type() == T_DOUBLE)) {
839 ++parameter_count; // need room for return value
840 }
841 if (target->method_holder()->is_interface()) {
842 assem.invokespecial(target);
843 } else {
844 assem.invokevirtual(target);
845 }
847 if (in.is_object() && in.as_symbol(THREAD) != out.as_symbol(THREAD)) {
848 assem.checkcast(in.as_symbol(THREAD));
849 }
850 assem._return(in.type());
851 return parameter_count;
852 }
854 static int assemble_method_error(
855 BytecodeConstantPool* cp, BytecodeBuffer* buffer, Symbol* errorName, Symbol* message, TRAPS) {
857 Symbol* init = vmSymbols::object_initializer_name();
858 Symbol* sig = vmSymbols::string_void_signature();
860 BytecodeAssembler assem(buffer, cp);
862 assem._new(errorName);
863 assem.dup();
864 assem.load_string(message);
865 assem.invokespecial(errorName, init, sig);
866 assem.athrow();
868 return 3; // max stack size: [ exception, exception, string ]
869 }
871 static Method* new_method(
872 BytecodeConstantPool* cp, BytecodeBuffer* bytecodes, Symbol* name,
873 Symbol* sig, AccessFlags flags, int max_stack, int params,
874 ConstMethod::MethodType mt, TRAPS) {
876 address code_start = 0;
877 int code_length = 0;
878 InlineTableSizes sizes;
880 if (bytecodes != NULL && bytecodes->length() > 0) {
881 code_start = static_cast<address>(bytecodes->adr_at(0));
882 code_length = bytecodes->length();
883 }
885 Method* m = Method::allocate(cp->pool_holder()->class_loader_data(),
886 code_length, flags, &sizes,
887 mt, CHECK_NULL);
889 m->set_constants(NULL); // This will get filled in later
890 m->set_name_index(cp->utf8(name));
891 m->set_signature_index(cp->utf8(sig));
892 #ifdef CC_INTERP
893 ResultTypeFinder rtf(sig);
894 m->set_result_index(rtf.type());
895 #endif
896 m->set_size_of_parameters(params);
897 m->set_max_stack(max_stack);
898 m->set_max_locals(params);
899 m->constMethod()->set_stackmap_data(NULL);
900 m->set_code(code_start);
901 m->set_force_inline(true);
903 return m;
904 }
906 static void switchover_constant_pool(BytecodeConstantPool* bpool,
907 InstanceKlass* klass, GrowableArray<Method*>* new_methods, TRAPS) {
909 if (new_methods->length() > 0) {
910 ConstantPool* cp = bpool->create_constant_pool(CHECK);
911 if (cp != klass->constants()) {
912 klass->class_loader_data()->add_to_deallocate_list(klass->constants());
913 klass->set_constants(cp);
914 cp->set_pool_holder(klass);
916 for (int i = 0; i < new_methods->length(); ++i) {
917 new_methods->at(i)->set_constants(cp);
918 }
919 for (int i = 0; i < klass->methods()->length(); ++i) {
920 Method* mo = klass->methods()->at(i);
921 mo->set_constants(cp);
922 }
923 }
924 }
925 }
927 // A "bridge" is a method created by javac to bridge the gap between
928 // an implementation and a generically-compatible, but different, signature.
929 // Bridges have actual bytecode implementation in classfiles.
930 // An "overpass", on the other hand, performs the same function as a bridge
931 // but does not occur in a classfile; the VM creates overpass itself,
932 // when it needs a path to get from a call site to an default method, and
933 // a bridge doesn't exist.
934 static void create_overpasses(
935 GrowableArray<EmptyVtableSlot*>* slots,
936 InstanceKlass* klass, TRAPS) {
938 GrowableArray<Method*> overpasses;
939 BytecodeConstantPool bpool(klass->constants());
941 for (int i = 0; i < slots->length(); ++i) {
942 EmptyVtableSlot* slot = slots->at(i);
944 if (slot->is_bound()) {
945 MethodFamily* method = slot->get_binding();
946 int max_stack = 0;
947 BytecodeBuffer buffer;
949 #ifndef PRODUCT
950 if (TraceDefaultMethods) {
951 tty->print("for slot: ");
952 slot->print_on(tty);
953 tty->print_cr("");
954 if (method->has_target()) {
955 method->print_selected(tty, 1);
956 } else {
957 method->print_exception(tty, 1);
958 }
959 }
960 #endif // ndef PRODUCT
961 if (method->has_target()) {
962 Method* selected = method->get_selected_target();
963 if (selected->method_holder()->is_interface()) {
964 max_stack = assemble_redirect(
965 &bpool, &buffer, slot->signature(), selected, CHECK);
966 }
967 } else if (method->throws_exception()) {
968 max_stack = assemble_method_error(&bpool, &buffer, method->get_exception_name(), method->get_exception_message(), CHECK);
969 }
970 if (max_stack != 0) {
971 AccessFlags flags = accessFlags_from(
972 JVM_ACC_PUBLIC | JVM_ACC_SYNTHETIC | JVM_ACC_BRIDGE);
973 Method* m = new_method(&bpool, &buffer, slot->name(), slot->signature(),
974 flags, max_stack, slot->size_of_parameters(),
975 ConstMethod::OVERPASS, CHECK);
976 if (m != NULL) {
977 overpasses.push(m);
978 }
979 }
980 }
981 }
983 #ifndef PRODUCT
984 if (TraceDefaultMethods) {
985 tty->print_cr("Created %d overpass methods", overpasses.length());
986 }
987 #endif // ndef PRODUCT
989 switchover_constant_pool(&bpool, klass, &overpasses, CHECK);
990 merge_in_new_methods(klass, &overpasses, CHECK);
991 }
993 static void sort_methods(GrowableArray<Method*>* methods) {
994 // Note that this must sort using the same key as is used for sorting
995 // methods in InstanceKlass.
996 bool sorted = true;
997 for (int i = methods->length() - 1; i > 0; --i) {
998 for (int j = 0; j < i; ++j) {
999 Method* m1 = methods->at(j);
1000 Method* m2 = methods->at(j + 1);
1001 if ((uintptr_t)m1->name() > (uintptr_t)m2->name()) {
1002 methods->at_put(j, m2);
1003 methods->at_put(j + 1, m1);
1004 sorted = false;
1005 }
1006 }
1007 if (sorted) break;
1008 sorted = true;
1009 }
1010 #ifdef ASSERT
1011 uintptr_t prev = 0;
1012 for (int i = 0; i < methods->length(); ++i) {
1013 Method* mh = methods->at(i);
1014 uintptr_t nv = (uintptr_t)mh->name();
1015 assert(nv >= prev, "Incorrect overpass method ordering");
1016 prev = nv;
1017 }
1018 #endif
1019 }
1021 static void merge_in_new_methods(InstanceKlass* klass,
1022 GrowableArray<Method*>* new_methods, TRAPS) {
1024 enum { ANNOTATIONS, PARAMETERS, DEFAULTS, NUM_ARRAYS };
1026 Array<Method*>* original_methods = klass->methods();
1027 Array<int>* original_ordering = klass->method_ordering();
1028 Array<int>* merged_ordering = Universe::the_empty_int_array();
1030 int new_size = klass->methods()->length() + new_methods->length();
1032 Array<Method*>* merged_methods = MetadataFactory::new_array<Method*>(
1033 klass->class_loader_data(), new_size, NULL, CHECK);
1035 if (original_ordering != NULL && original_ordering->length() > 0) {
1036 merged_ordering = MetadataFactory::new_array<int>(
1037 klass->class_loader_data(), new_size, CHECK);
1038 }
1039 int method_order_index = klass->methods()->length();
1041 sort_methods(new_methods);
1043 // Perform grand merge of existing methods and new methods
1044 int orig_idx = 0;
1045 int new_idx = 0;
1047 for (int i = 0; i < new_size; ++i) {
1048 Method* orig_method = NULL;
1049 Method* new_method = NULL;
1050 if (orig_idx < original_methods->length()) {
1051 orig_method = original_methods->at(orig_idx);
1052 }
1053 if (new_idx < new_methods->length()) {
1054 new_method = new_methods->at(new_idx);
1055 }
1057 if (orig_method != NULL &&
1058 (new_method == NULL || orig_method->name() < new_method->name())) {
1059 merged_methods->at_put(i, orig_method);
1060 original_methods->at_put(orig_idx, NULL);
1061 if (merged_ordering->length() > 0) {
1062 merged_ordering->at_put(i, original_ordering->at(orig_idx));
1063 }
1064 ++orig_idx;
1065 } else {
1066 merged_methods->at_put(i, new_method);
1067 if (merged_ordering->length() > 0) {
1068 merged_ordering->at_put(i, method_order_index++);
1069 }
1070 ++new_idx;
1071 }
1072 // update idnum for new location
1073 merged_methods->at(i)->set_method_idnum(i);
1074 }
1076 // Verify correct order
1077 #ifdef ASSERT
1078 uintptr_t prev = 0;
1079 for (int i = 0; i < merged_methods->length(); ++i) {
1080 Method* mo = merged_methods->at(i);
1081 uintptr_t nv = (uintptr_t)mo->name();
1082 assert(nv >= prev, "Incorrect method ordering");
1083 prev = nv;
1084 }
1085 #endif
1087 // Replace klass methods with new merged lists
1088 klass->set_methods(merged_methods);
1089 klass->set_initial_method_idnum(new_size);
1091 ClassLoaderData* cld = klass->class_loader_data();
1092 MetadataFactory::free_array(cld, original_methods);
1093 if (original_ordering->length() > 0) {
1094 klass->set_method_ordering(merged_ordering);
1095 MetadataFactory::free_array(cld, original_ordering);
1096 }
1097 }