30 #include "memory/resourceArea.hpp"
31 #include "memory/universe.inline.hpp"
32 #include "oops/instanceKlass.hpp"
33 #include "oops/klassVtable.hpp"
34 #include "oops/method.hpp"
35 #include "oops/objArrayOop.hpp"
36 #include "oops/oop.inline.hpp"
37 #include "prims/jvmtiRedefineClassesTrace.hpp"
38 #include "runtime/arguments.hpp"
39 #include "runtime/handles.inline.hpp"
40 #include "utilities/copy.hpp"
41
42 inline InstanceKlass* klassVtable::ik() const {
43 Klass* k = _klass();
44 assert(k->oop_is_instance(), "not an InstanceKlass");
45 return (InstanceKlass*)k;
46 }
47
48
49 // this function computes the vtable size (including the size needed for miranda
50 // methods) and the number of miranda methods in this class
51 // Note on Miranda methods: Let's say there is a class C that implements
52 // interface I. Let's say there is a method m in I that neither C nor any
53 // of its super classes implement (i.e there is no method of any access, with
54 // the same name and signature as m), then m is a Miranda method which is
55 // entered as a public abstract method in C's vtable. From then on it should
56 // treated as any other public method in C for method over-ride purposes.
57 void klassVtable::compute_vtable_size_and_num_mirandas(
58 int* vtable_length_ret, int* num_new_mirandas,
59 GrowableArray<Method*>* all_mirandas, Klass* super,
60 Array<Method*>* methods, AccessFlags class_flags,
61 Handle classloader, Symbol* classname, Array<Klass*>* local_interfaces,
62 TRAPS) {
63 No_Safepoint_Verifier nsv;
64
65 // set up default result values
66 int vtable_length = 0;
67
68 // start off with super's vtable length
69 InstanceKlass* sk = (InstanceKlass*)super;
70 vtable_length = super == NULL ? 0 : sk->vtable_length();
71
72 // go thru each method in the methods table to see if it needs a new entry
73 int len = methods->length();
74 for (int i = 0; i < len; i++) {
94 }
95
96 if (super == NULL && !Universe::is_bootstrapping() &&
97 vtable_length != Universe::base_vtable_size()) {
98 // Someone is attempting to redefine java.lang.Object incorrectly. The
99 // only way this should happen is from
100 // SystemDictionary::resolve_from_stream(), which will detect this later
101 // and throw a security exception. So don't assert here to let
102 // the exception occur.
103 vtable_length = Universe::base_vtable_size();
104 }
105 assert(super != NULL || vtable_length == Universe::base_vtable_size(),
106 "bad vtable size for class Object");
107 assert(vtable_length % vtableEntry::size() == 0, "bad vtable length");
108 assert(vtable_length >= Universe::base_vtable_size(), "vtable too small");
109
110 *vtable_length_ret = vtable_length;
111 }
112
113 int klassVtable::index_of(Method* m, int len) const {
114 assert(m->vtable_index() >= 0, "do not ask this of non-vtable methods");
115 return m->vtable_index();
116 }
117
118 int klassVtable::initialize_from_super(KlassHandle super) {
119 if (super.is_null()) {
120 return 0;
121 } else {
122 // copy methods from superKlass
123 // can't inherit from array class, so must be InstanceKlass
124 assert(super->oop_is_instance(), "must be instance klass");
125 InstanceKlass* sk = (InstanceKlass*)super();
126 klassVtable* superVtable = sk->vtable();
127 assert(superVtable->length() <= _length, "vtable too short");
128 #ifdef ASSERT
129 superVtable->verify(tty, true);
130 #endif
131 superVtable->copy_vtable_to(table());
132 #ifndef PRODUCT
133 if (PrintVtables && Verbose) {
134 ResourceMark rm;
135 tty->print_cr("copy vtable from %s to %s size %d", sk->internal_name(), klass()->internal_name(), _length);
136 }
137 #endif
138 return superVtable->length();
139 }
140 }
141
142 // Revised lookup semantics introduced 1.3 (Kestral beta)
143 void klassVtable::initialize_vtable(bool checkconstraints, TRAPS) {
144
145 // Note: Arrays can have intermediate array supers. Use java_super to skip them.
146 KlassHandle super (THREAD, klass()->java_super());
147 int nofNewEntries = 0;
148
149
150 if (PrintVtables && !klass()->oop_is_array()) {
151 ResourceMark rm(THREAD);
152 tty->print_cr("Initializing: %s", _klass->name()->as_C_string());
153 }
154
155 #ifdef ASSERT
156 oop* end_of_obj = (oop*)_klass() + _klass()->size();
157 oop* end_of_vtable = (oop*)&table()[_length];
158 assert(end_of_vtable <= end_of_obj, "vtable extends beyond end");
159 #endif
160
161 if (Universe::is_bootstrapping()) {
162 // just clear everything
163 for (int i = 0; i < _length; i++) table()[i].clear();
164 return;
165 }
166
167 int super_vtable_len = initialize_from_super(super);
168 if (klass()->oop_is_array()) {
169 assert(super_vtable_len == _length, "arrays shouldn't introduce new methods");
170 } else {
171 assert(_klass->oop_is_instance(), "must be InstanceKlass");
172
173 Array<Method*>* methods = ik()->methods();
174 int len = methods->length();
175 int initialized = super_vtable_len;
176
177 // update_inherited_vtable can stop for gc - ensure using handles
178 for (int i = 0; i < len; i++) {
179 HandleMark hm(THREAD);
180 assert(methods->at(i)->is_method(), "must be a Method*");
181 methodHandle mh(THREAD, methods->at(i));
182
183 bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, checkconstraints, CHECK);
184
185 if (needs_new_entry) {
186 put_method_at(mh(), initialized);
187 mh()->set_vtable_index(initialized); // set primary vtable index
188 initialized++;
189 }
190 }
191
192 // add miranda methods; it will also update the value of initialized
193 fill_in_mirandas(&initialized);
194
195 // In class hierarchies where the accessibility is not increasing (i.e., going from private ->
196 // package_private -> publicprotected), the vtable might actually be smaller than our initial
197 // calculation.
198 assert(initialized <= _length, "vtable initialization failed");
199 for(;initialized < _length; initialized++) {
200 put_method_at(NULL, initialized);
201 }
202 NOT_PRODUCT(verify(tty, true));
203 }
204 }
205
206 // Called for cases where a method does not override its superclass' vtable entry
207 // For bytecodes not produced by javac together it is possible that a method does not override
208 // the superclass's method, but might indirectly override a super-super class's vtable entry
209 // If none found, return a null superk, else return the superk of the method this does override
210 InstanceKlass* klassVtable::find_transitive_override(InstanceKlass* initialsuper, methodHandle target_method,
211 int vtable_index, Handle target_loader, Symbol* target_classname, Thread * THREAD) {
212 InstanceKlass* superk = initialsuper;
213 while (superk != NULL && superk->super() != NULL) {
214 InstanceKlass* supersuperklass = InstanceKlass::cast(superk->super());
215 klassVtable* ssVtable = supersuperklass->vtable();
216 if (vtable_index < ssVtable->length()) {
231 super_method->access_flags().print_on(tty);
232 tty->print("overriders flags: ");
233 target_method->access_flags().print_on(tty);
234 tty->cr();
235 }
236 #endif /*PRODUCT*/
237 break; // return found superk
238 }
239 } else {
240 // super class has no vtable entry here, stop transitive search
241 superk = (InstanceKlass*)NULL;
242 break;
243 }
244 // if no override found yet, continue to search up
245 superk = InstanceKlass::cast(superk->super());
246 }
247
248 return superk;
249 }
250
251 // Methods that are "effectively" final don't need vtable entries.
252 bool method_is_effectively_final(
253 AccessFlags klass_flags, methodHandle target) {
254 return target->is_final() || klass_flags.is_final() && !target->is_overpass();
255 }
256
257 // Update child's copy of super vtable for overrides
258 // OR return true if a new vtable entry is required
259 // Only called for InstanceKlass's, i.e. not for arrays
260 // If that changed, could not use _klass as handle for klass
261 bool klassVtable::update_inherited_vtable(InstanceKlass* klass, methodHandle target_method, int super_vtable_len,
262 bool checkconstraints, TRAPS) {
263 ResourceMark rm;
264 bool allocate_new = true;
265 assert(klass->oop_is_instance(), "must be InstanceKlass");
266
267 // Initialize the method's vtable index to "nonvirtual".
268 // If we allocate a vtable entry, we will update it to a non-negative number.
269 target_method()->set_vtable_index(Method::nonvirtual_vtable_index);
270
271 // Static and <init> methods are never in
272 if (target_method()->is_static() || target_method()->name() == vmSymbols::object_initializer_name()) {
273 return false;
274 }
275
276 if (method_is_effectively_final(klass->access_flags(), target_method)) {
277 // a final method never needs a new entry; final methods can be statically
278 // resolved and they have to be present in the vtable only if they override
279 // a super's method, in which case they re-use its entry
280 allocate_new = false;
281 }
282
283 // we need a new entry if there is no superclass
284 if (klass->super() == NULL) {
285 return allocate_new;
286 }
287
288 // private methods always have a new entry in the vtable
289 // specification interpretation since classic has
290 // private methods not overriding
291 if (target_method()->is_private()) {
292 return allocate_new;
293 }
294
295 // search through the vtable and update overridden entries
296 // Since check_signature_loaders acquires SystemDictionary_lock
297 // which can block for gc, once we are in this loop, use handles
298 // For classfiles built with >= jdk7, we now look for transitive overrides
299
300 Symbol* name = target_method()->name();
394 }
395 #endif
396 table()[index].set(m);
397 }
398
399 // Find out if a method "m" with superclass "super", loader "classloader" and
400 // name "classname" needs a new vtable entry. Let P be a class package defined
401 // by "classloader" and "classname".
402 // NOTE: The logic used here is very similar to the one used for computing
403 // the vtables indices for a method. We cannot directly use that function because,
404 // we allocate the InstanceKlass at load time, and that requires that the
405 // superclass has been loaded.
406 // However, the vtable entries are filled in at link time, and therefore
407 // the superclass' vtable may not yet have been filled in.
408 bool klassVtable::needs_new_vtable_entry(methodHandle target_method,
409 Klass* super,
410 Handle classloader,
411 Symbol* classname,
412 AccessFlags class_flags,
413 TRAPS) {
414
415 if (method_is_effectively_final(class_flags, target_method) ||
416 // a final method never needs a new entry; final methods can be statically
417 // resolved and they have to be present in the vtable only if they override
418 // a super's method, in which case they re-use its entry
419 (target_method()->is_static()) ||
420 // static methods don't need to be in vtable
421 (target_method()->name() == vmSymbols::object_initializer_name())
422 // <init> is never called dynamically-bound
423 ) {
424 return false;
425 }
426
427 // we need a new entry if there is no superclass
428 if (super == NULL) {
429 return true;
430 }
431
432 // private methods always have a new entry in the vtable
433 // specification interpretation since classic has
434 // private methods not overriding
435 if (target_method()->is_private()) {
483 }
484 }
485 return true; // found no match; we need a new entry
486 }
487
488 // Support for miranda methods
489
490 // get the vtable index of a miranda method with matching "name" and "signature"
491 int klassVtable::index_of_miranda(Symbol* name, Symbol* signature) {
492 // search from the bottom, might be faster
493 for (int i = (length() - 1); i >= 0; i--) {
494 Method* m = table()[i].method();
495 if (is_miranda_entry_at(i) &&
496 m->name() == name && m->signature() == signature) {
497 return i;
498 }
499 }
500 return Method::invalid_vtable_index;
501 }
502
503 // check if an entry is miranda
504 bool klassVtable::is_miranda_entry_at(int i) {
505 Method* m = method_at(i);
506 Klass* method_holder = m->method_holder();
507 InstanceKlass *mhk = InstanceKlass::cast(method_holder);
508
509 // miranda methods are interface methods in a class's vtable
510 if (mhk->is_interface()) {
511 assert(m->is_public(), "should be public");
512 assert(ik()->implements_interface(method_holder) , "this class should implement the interface");
513 assert(is_miranda(m, ik()->methods(), ik()->super()), "should be a miranda_method");
514 return true;
515 }
516 return false;
517 }
518
519 // check if a method is a miranda method, given a class's methods table and it's super
520 // the caller must make sure that the method belongs to an interface implemented by the class
521 bool klassVtable::is_miranda(Method* m, Array<Method*>* class_methods, Klass* super) {
522 if (m->is_static()) {
523 return false;
524 }
525 Symbol* name = m->name();
526 Symbol* signature = m->signature();
527 if (InstanceKlass::find_method(class_methods, name, signature) == NULL) {
528 // did not find it in the method table of the current class
529 if (super == NULL) {
530 // super doesn't exist
531 return true;
532 }
533
534 Method* mo = InstanceKlass::cast(super)->lookup_method(name, signature);
535 if (mo == NULL || mo->access_flags().is_private() ) {
536 // super class hierarchy does not implement it or protection is different
537 return true;
538 }
539 }
540
541 return false;
542 }
543
544 void klassVtable::add_new_mirandas_to_lists(
545 GrowableArray<Method*>* new_mirandas, GrowableArray<Method*>* all_mirandas,
546 Array<Method*>* current_interface_methods, Array<Method*>* class_methods,
547 Klass* super) {
548 // iterate thru the current interface's method to see if it a miranda
549 int num_methods = current_interface_methods->length();
550 for (int i = 0; i < num_methods; i++) {
551 Method* im = current_interface_methods->at(i);
552 bool is_duplicate = false;
553 int num_of_current_mirandas = new_mirandas->length();
554 // check for duplicate mirandas in different interfaces we implement
555 for (int j = 0; j < num_of_current_mirandas; j++) {
556 Method* miranda = new_mirandas->at(j);
557 if ((im->name() == miranda->name()) &&
558 (im->signature() == miranda->signature())) {
559 is_duplicate = true;
560 break;
561 }
562 }
563
582 Array<Klass*>* local_interfaces) {
583 assert((new_mirandas->length() == 0) , "current mirandas must be 0");
584
585 // iterate thru the local interfaces looking for a miranda
586 int num_local_ifs = local_interfaces->length();
587 for (int i = 0; i < num_local_ifs; i++) {
588 InstanceKlass *ik = InstanceKlass::cast(local_interfaces->at(i));
589 add_new_mirandas_to_lists(new_mirandas, all_mirandas,
590 ik->methods(), class_methods, super);
591 // iterate thru each local's super interfaces
592 Array<Klass*>* super_ifs = ik->transitive_interfaces();
593 int num_super_ifs = super_ifs->length();
594 for (int j = 0; j < num_super_ifs; j++) {
595 InstanceKlass *sik = InstanceKlass::cast(super_ifs->at(j));
596 add_new_mirandas_to_lists(new_mirandas, all_mirandas,
597 sik->methods(), class_methods, super);
598 }
599 }
600 }
601
602 // fill in mirandas
603 void klassVtable::fill_in_mirandas(int* initialized) {
604 GrowableArray<Method*> mirandas(20);
605 get_mirandas(&mirandas, NULL, ik()->super(), ik()->methods(),
606 ik()->local_interfaces());
607 for (int i = 0; i < mirandas.length(); i++) {
608 put_method_at(mirandas.at(i), *initialized);
609 ++(*initialized);
610 }
611 }
612
613 void klassVtable::copy_vtable_to(vtableEntry* start) {
614 Copy::disjoint_words((HeapWord*)table(), (HeapWord*)start, _length * vtableEntry::size());
615 }
616
617 #if INCLUDE_JVMTI
618 void klassVtable::adjust_method_entries(Method** old_methods, Method** new_methods,
619 int methods_length, bool * trace_name_printed) {
620 // search the vtable for uses of either obsolete or EMCP methods
621 for (int j = 0; j < methods_length; j++) {
622 Method* old_method = old_methods[j];
623 Method* new_method = new_methods[j];
624
625 // In the vast majority of cases we could get the vtable index
626 // by using: old_method->vtable_index()
627 // However, there are rare cases, eg. sun.awt.X11.XDecoratedPeer.getX()
628 // in sun.awt.X11.XFramePeer where methods occur more than once in the
629 // vtable, so, alas, we must do an exhaustive search.
630 for (int index = 0; index < length(); index++) {
631 if (unchecked_method_at(index) == old_method) {
632 put_method_at(new_method, index);
706 intptr_t* end = klass->end_of_itable();
707
708 _table_offset = (intptr_t*)offset_entry - (intptr_t*)klass();
709 _size_offset_table = (method_entry - ((intptr_t*)offset_entry)) / itableOffsetEntry::size();
710 _size_method_table = (end - method_entry) / itableMethodEntry::size();
711 assert(_table_offset >= 0 && _size_offset_table >= 0 && _size_method_table >= 0, "wrong computation");
712 return;
713 }
714 }
715
716 // The length of the itable was either zero, or it has not yet been initialized.
717 _table_offset = 0;
718 _size_offset_table = 0;
719 _size_method_table = 0;
720 }
721
722 static int initialize_count = 0;
723
724 // Initialization
725 void klassItable::initialize_itable(bool checkconstraints, TRAPS) {
726 // Cannot be setup doing bootstrapping, interfaces don't have
727 // itables, and klass with only ones entry have empty itables
728 if (Universe::is_bootstrapping() ||
729 _klass->is_interface() ||
730 _klass->itable_length() == itableOffsetEntry::size()) return;
731
732 // There's alway an extra itable entry so we can null-terminate it.
733 guarantee(size_offset_table() >= 1, "too small");
734 int num_interfaces = size_offset_table() - 1;
735 if (num_interfaces > 0) {
736 if (TraceItables) tty->print_cr("%3d: Initializing itables for %s", ++initialize_count,
737 _klass->name()->as_C_string());
738
739
740 // Iterate through all interfaces
741 int i;
742 for(i = 0; i < num_interfaces; i++) {
743 itableOffsetEntry* ioe = offset_entry(i);
744 HandleMark hm(THREAD);
745 KlassHandle interf_h (THREAD, ioe->interface_klass());
746 assert(interf_h() != NULL && ioe->offset() != 0, "bad offset entry in itable");
747 initialize_itable_for_interface(ioe->offset(), interf_h, checkconstraints, CHECK);
748 }
749
750 }
751 // Check that the last entry is empty
752 itableOffsetEntry* ioe = offset_entry(size_offset_table() - 1);
753 guarantee(ioe->interface_klass() == NULL && ioe->offset() == 0, "terminator entry missing");
754 }
755
756
757 void klassItable::initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS) {
758 Array<Method*>* methods = InstanceKlass::cast(interf_h())->methods();
759 int nof_methods = methods->length();
760 HandleMark hm;
761 KlassHandle klass = _klass;
762 assert(nof_methods > 0, "at least one method must exist for interface to be in vtable");
763 Handle interface_loader (THREAD, InstanceKlass::cast(interf_h())->class_loader());
764 int ime_num = 0;
765
766 // Skip first Method* if it is a class initializer
767 int i = methods->at(0)->is_static_initializer() ? 1 : 0;
768
769 // m, method_name, method_signature, klass reset each loop so they
770 // don't need preserving across check_signature_loaders call
771 // methods needs a handle in case of gc from check_signature_loaders
772 for(; i < nof_methods; i++) {
773 Method* m = methods->at(i);
774 Symbol* method_name = m->name();
775 Symbol* method_signature = m->signature();
776
777 // This is same code as in Linkresolver::lookup_instance_method_in_klasses
778 Method* target = klass->uncached_lookup_method(method_name, method_signature);
779 while (target != NULL && target->is_static()) {
780 // continue with recursive lookup through the superclass
781 Klass* super = target->method_holder()->super();
782 target = (super == NULL) ? (Method*)NULL : super->uncached_lookup_method(method_name, method_signature);
783 }
784 if (target == NULL || !target->is_public() || target->is_abstract()) {
785 // Entry do not resolve. Leave it empty
786 } else {
787 // Entry did resolve, check loader constraints before initializing
788 // if checkconstraints requested
789 methodHandle target_h (THREAD, target); // preserve across gc
790 if (checkconstraints) {
791 Handle method_holder_loader (THREAD, target->method_holder()->class_loader());
792 if (method_holder_loader() != interface_loader()) {
793 ResourceMark rm(THREAD);
794 Symbol* failed_type_symbol =
795 SystemDictionary::check_signature_loaders(method_signature,
796 method_holder_loader,
797 interface_loader,
798 true, CHECK);
799 if (failed_type_symbol != NULL) {
800 const char* msg = "loader constraint violation in interface "
801 "itable initialization: when resolving method \"%s\" the class"
802 " loader (instance of %s) of the current class, %s, "
803 "and the class loader (instance of %s) for interface "
804 "%s have different Class objects for the type %s "
805 "used in the signature";
806 char* sig = target_h()->name_and_sig_as_C_string();
807 const char* loader1 = SystemDictionary::loader_name(method_holder_loader());
808 char* current = klass->name()->as_C_string();
809 const char* loader2 = SystemDictionary::loader_name(interface_loader());
810 char* iface = InstanceKlass::cast(interf_h())->name()->as_C_string();
811 char* failed_type_name = failed_type_symbol->as_C_string();
812 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
813 strlen(current) + strlen(loader2) + strlen(iface) +
814 strlen(failed_type_name);
815 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
816 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2,
817 iface, failed_type_name);
818 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
819 }
820 }
821 }
822
823 // ime may have moved during GC so recalculate address
824 itableOffsetEntry::method_entry(_klass(), method_table_offset)[ime_num].initialize(target_h());
825 }
826 // Progress to next entry
827 ime_num++;
828 }
829 }
830
831 // Update entry for specific Method*
832 void klassItable::initialize_with_method(Method* m) {
833 itableMethodEntry* ime = method_entry(0);
834 for(int i = 0; i < _size_method_table; i++) {
835 if (ime->method() == m) {
836 ime->initialize(m);
837 }
838 ime++;
839 }
840 }
841
842 #if INCLUDE_JVMTI
843 void klassItable::adjust_method_entries(Method** old_methods, Method** new_methods,
844 int methods_length, bool * trace_name_printed) {
845 // search the itable for uses of either obsolete or EMCP methods
846 for (int j = 0; j < methods_length; j++) {
847 Method* old_method = old_methods[j];
896 Method* m = ime->method();
897 if (m != NULL) {
898 tty->print(" (%5d) ", i);
899 m->access_flags().print_on(tty);
900 tty->print(" -- ");
901 m->print_name(tty);
902 tty->cr();
903 }
904 ime++;
905 }
906 }
907 #endif // INCLUDE_JVMTI
908
909
910 // Setup
911 class InterfaceVisiterClosure : public StackObj {
912 public:
913 virtual void doit(Klass* intf, int method_count) = 0;
914 };
915
916 // Visit all interfaces with at-least one method (excluding <clinit>)
917 void visit_all_interfaces(Array<Klass*>* transitive_intf, InterfaceVisiterClosure *blk) {
918 // Handle array argument
919 for(int i = 0; i < transitive_intf->length(); i++) {
920 Klass* intf = transitive_intf->at(i);
921 assert(intf->is_interface(), "sanity check");
922
923 // Find no. of methods excluding a <clinit>
924 int method_count = InstanceKlass::cast(intf)->methods()->length();
925 if (method_count > 0) {
926 Method* m = InstanceKlass::cast(intf)->methods()->at(0);
927 assert(m != NULL && m->is_method(), "sanity check");
928 if (m->name() == vmSymbols::object_initializer_name()) {
929 method_count--;
930 }
931 }
932
933 // Only count interfaces with at least one method
934 if (method_count > 0) {
935 blk->doit(intf, method_count);
936 }
937 }
938 }
939
940 class CountInterfacesClosure : public InterfaceVisiterClosure {
941 private:
942 int _nof_methods;
943 int _nof_interfaces;
944 public:
945 CountInterfacesClosure() { _nof_methods = 0; _nof_interfaces = 0; }
946
947 int nof_methods() const { return _nof_methods; }
948 int nof_interfaces() const { return _nof_interfaces; }
949
1007
1008 // Fill-out offset table
1009 itableOffsetEntry* ioe = (itableOffsetEntry*)klass->start_of_itable();
1010 itableMethodEntry* ime = (itableMethodEntry*)(ioe + nof_interfaces);
1011 intptr_t* end = klass->end_of_itable();
1012 assert((oop*)(ime + nof_methods) <= (oop*)klass->start_of_nonstatic_oop_maps(), "wrong offset calculation (1)");
1013 assert((oop*)(end) == (oop*)(ime + nof_methods), "wrong offset calculation (2)");
1014
1015 // Visit all interfaces and initialize itable offset table
1016 SetupItableClosure sic((address)klass(), ioe, ime);
1017 visit_all_interfaces(klass->transitive_interfaces(), &sic);
1018
1019 #ifdef ASSERT
1020 ime = sic.method_entry();
1021 oop* v = (oop*) klass->end_of_itable();
1022 assert( (oop*)(ime) == v, "wrong offset calculation (2)");
1023 #endif
1024 }
1025
1026
1027 // m must be a method in an interface
1028 int klassItable::compute_itable_index(Method* m) {
1029 InstanceKlass* intf = m->method_holder();
1030 assert(intf->is_interface(), "sanity check");
1031 Array<Method*>* methods = intf->methods();
1032 int index = 0;
1033 while(methods->at(index) != m) {
1034 index++;
1035 assert(index < methods->length(), "should find index for resolve_invoke");
1036 }
1037 // Adjust for <clinit>, which is left out of table if first method
1038 if (methods->length() > 0 && methods->at(0)->is_static_initializer()) {
1039 index--;
1040 }
1041 return index;
1042 }
1043
1044
1045 // inverse to compute_itable_index
1046 Method* klassItable::method_for_itable_index(Klass* intf, int itable_index) {
1047 assert(InstanceKlass::cast(intf)->is_interface(), "sanity check");
1048 Array<Method*>* methods = InstanceKlass::cast(intf)->methods();
1049
1050 int index = itable_index;
1051 // Adjust for <clinit>, which is left out of table if first method
1052 if (methods->length() > 0 && methods->at(0)->is_static_initializer()) {
1053 index++;
1054 }
1055
1056 if (itable_index < 0 || index >= methods->length())
1057 return NULL; // help caller defend against bad indexes
1058
1059 Method* m = methods->at(index);
1060 assert(compute_itable_index(m) == itable_index, "correct inverse");
1061
1062 return m;
1063 }
1064
1065 void klassVtable::verify(outputStream* st, bool forced) {
1066 // make sure table is initialized
1067 if (!Universe::is_fully_initialized()) return;
1068 #ifndef PRODUCT
1069 // avoid redundant verifies
1070 if (!forced && _verify_count == Universe::verify_count()) return;
1071 _verify_count = Universe::verify_count();
1072 #endif
1073 oop* end_of_obj = (oop*)_klass() + _klass()->size();
1074 oop* end_of_vtable = (oop *)&table()[_length];
1075 if (end_of_vtable > end_of_obj) {
1076 fatal(err_msg("klass %s: klass object too short (vtable extends beyond "
1077 "end)", _klass->internal_name()));
1078 }
1079
1080 for (int i = 0; i < _length; i++) table()[i].verify(this, st);
|
30 #include "memory/resourceArea.hpp"
31 #include "memory/universe.inline.hpp"
32 #include "oops/instanceKlass.hpp"
33 #include "oops/klassVtable.hpp"
34 #include "oops/method.hpp"
35 #include "oops/objArrayOop.hpp"
36 #include "oops/oop.inline.hpp"
37 #include "prims/jvmtiRedefineClassesTrace.hpp"
38 #include "runtime/arguments.hpp"
39 #include "runtime/handles.inline.hpp"
40 #include "utilities/copy.hpp"
41
42 inline InstanceKlass* klassVtable::ik() const {
43 Klass* k = _klass();
44 assert(k->oop_is_instance(), "not an InstanceKlass");
45 return (InstanceKlass*)k;
46 }
47
48
49 // this function computes the vtable size (including the size needed for miranda
50 // methods) and the number of miranda methods in this class.
51 // Note on Miranda methods: Let's say there is a class C that implements
52 // interface I, and none of C's superclasses implements I.
53 // Let's say there is an abstract method m in I that neither C
54 // nor any of its super classes implement (i.e there is no method of any access,
55 // with the same name and signature as m), then m is a Miranda method which is
56 // entered as a public abstract method in C's vtable. From then on it should
57 // treated as any other public method in C for method over-ride purposes.
58 void klassVtable::compute_vtable_size_and_num_mirandas(
59 int* vtable_length_ret, int* num_new_mirandas,
60 GrowableArray<Method*>* all_mirandas, Klass* super,
61 Array<Method*>* methods, AccessFlags class_flags,
62 Handle classloader, Symbol* classname, Array<Klass*>* local_interfaces,
63 TRAPS) {
64 No_Safepoint_Verifier nsv;
65
66 // set up default result values
67 int vtable_length = 0;
68
69 // start off with super's vtable length
70 InstanceKlass* sk = (InstanceKlass*)super;
71 vtable_length = super == NULL ? 0 : sk->vtable_length();
72
73 // go thru each method in the methods table to see if it needs a new entry
74 int len = methods->length();
75 for (int i = 0; i < len; i++) {
95 }
96
97 if (super == NULL && !Universe::is_bootstrapping() &&
98 vtable_length != Universe::base_vtable_size()) {
99 // Someone is attempting to redefine java.lang.Object incorrectly. The
100 // only way this should happen is from
101 // SystemDictionary::resolve_from_stream(), which will detect this later
102 // and throw a security exception. So don't assert here to let
103 // the exception occur.
104 vtable_length = Universe::base_vtable_size();
105 }
106 assert(super != NULL || vtable_length == Universe::base_vtable_size(),
107 "bad vtable size for class Object");
108 assert(vtable_length % vtableEntry::size() == 0, "bad vtable length");
109 assert(vtable_length >= Universe::base_vtable_size(), "vtable too small");
110
111 *vtable_length_ret = vtable_length;
112 }
113
114 int klassVtable::index_of(Method* m, int len) const {
115 assert(m->has_vtable_index(), "do not ask this of non-vtable methods");
116 return m->vtable_index();
117 }
118
119 // Copy super class's vtable to the first part (prefix) of this class's vtable,
120 // and return the number of entries copied. Expects that 'super' is the Java
121 // super class (arrays can have "array" super classes that must be skipped).
122 int klassVtable::initialize_from_super(KlassHandle super) {
123 if (super.is_null()) {
124 return 0;
125 } else {
126 // copy methods from superKlass
127 // can't inherit from array class, so must be InstanceKlass
128 assert(super->oop_is_instance(), "must be instance klass");
129 InstanceKlass* sk = (InstanceKlass*)super();
130 klassVtable* superVtable = sk->vtable();
131 assert(superVtable->length() <= _length, "vtable too short");
132 #ifdef ASSERT
133 superVtable->verify(tty, true);
134 #endif
135 superVtable->copy_vtable_to(table());
136 #ifndef PRODUCT
137 if (PrintVtables && Verbose) {
138 ResourceMark rm;
139 tty->print_cr("copy vtable from %s to %s size %d", sk->internal_name(), klass()->internal_name(), _length);
140 }
141 #endif
142 return superVtable->length();
143 }
144 }
145
146 //
147 // Revised lookup semantics introduced 1.3 (Kestrel beta)
148 void klassVtable::initialize_vtable(bool checkconstraints, TRAPS) {
149
150 // Note: Arrays can have intermediate array supers. Use java_super to skip them.
151 KlassHandle super (THREAD, klass()->java_super());
152 int nofNewEntries = 0;
153
154 if (PrintVtables && !klass()->oop_is_array()) {
155 ResourceMark rm(THREAD);
156 tty->print_cr("Initializing: %s", _klass->name()->as_C_string());
157 }
158
159 #ifdef ASSERT
160 oop* end_of_obj = (oop*)_klass() + _klass()->size();
161 oop* end_of_vtable = (oop*)&table()[_length];
162 assert(end_of_vtable <= end_of_obj, "vtable extends beyond end");
163 #endif
164
165 if (Universe::is_bootstrapping()) {
166 // just clear everything
167 for (int i = 0; i < _length; i++) table()[i].clear();
168 return;
169 }
170
171 int super_vtable_len = initialize_from_super(super);
172 if (klass()->oop_is_array()) {
173 assert(super_vtable_len == _length, "arrays shouldn't introduce new methods");
174 } else {
175 assert(_klass->oop_is_instance(), "must be InstanceKlass");
176
177 Array<Method*>* methods = ik()->methods();
178 int len = methods->length();
179 int initialized = super_vtable_len;
180
181 // Check each of this class's methods against super;
182 // if override, replace in copy of super vtable, otherwise append to end
183 for (int i = 0; i < len; i++) {
184 // update_inherited_vtable can stop for gc - ensure using handles
185 HandleMark hm(THREAD);
186 assert(methods->at(i)->is_method(), "must be a Method*");
187 methodHandle mh(THREAD, methods->at(i));
188
189 bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, checkconstraints, CHECK);
190
191 if (needs_new_entry) {
192 put_method_at(mh(), initialized);
193 mh()->set_vtable_index(initialized); // set primary vtable index
194 initialized++;
195 }
196 }
197
198 // add miranda methods to end of vtable.
199 initialized = fill_in_mirandas(initialized);
200
201 // In class hierarchies where the accessibility is not increasing (i.e., going from private ->
202 // package_private -> public/protected), the vtable might actually be smaller than our initial
203 // calculation.
204 assert(initialized <= _length, "vtable initialization failed");
205 for(;initialized < _length; initialized++) {
206 put_method_at(NULL, initialized);
207 }
208 NOT_PRODUCT(verify(tty, true));
209 }
210 }
211
212 // Called for cases where a method does not override its superclass' vtable entry
213 // For bytecodes not produced by javac together it is possible that a method does not override
214 // the superclass's method, but might indirectly override a super-super class's vtable entry
215 // If none found, return a null superk, else return the superk of the method this does override
216 InstanceKlass* klassVtable::find_transitive_override(InstanceKlass* initialsuper, methodHandle target_method,
217 int vtable_index, Handle target_loader, Symbol* target_classname, Thread * THREAD) {
218 InstanceKlass* superk = initialsuper;
219 while (superk != NULL && superk->super() != NULL) {
220 InstanceKlass* supersuperklass = InstanceKlass::cast(superk->super());
221 klassVtable* ssVtable = supersuperklass->vtable();
222 if (vtable_index < ssVtable->length()) {
237 super_method->access_flags().print_on(tty);
238 tty->print("overriders flags: ");
239 target_method->access_flags().print_on(tty);
240 tty->cr();
241 }
242 #endif /*PRODUCT*/
243 break; // return found superk
244 }
245 } else {
246 // super class has no vtable entry here, stop transitive search
247 superk = (InstanceKlass*)NULL;
248 break;
249 }
250 // if no override found yet, continue to search up
251 superk = InstanceKlass::cast(superk->super());
252 }
253
254 return superk;
255 }
256
257 // Update child's copy of super vtable for overrides
258 // OR return true if a new vtable entry is required.
259 // Only called for InstanceKlass's, i.e. not for arrays
260 // If that changed, could not use _klass as handle for klass
261 bool klassVtable::update_inherited_vtable(InstanceKlass* klass, methodHandle target_method, int super_vtable_len,
262 bool checkconstraints, TRAPS) {
263 ResourceMark rm;
264 bool allocate_new = true;
265 assert(klass->oop_is_instance(), "must be InstanceKlass");
266 assert(klass == target_method()->method_holder(), "caller resp.");
267
268 // Initialize the method's vtable index to "nonvirtual".
269 // If we allocate a vtable entry, we will update it to a non-negative number.
270 target_method()->set_vtable_index(Method::nonvirtual_vtable_index);
271
272 // Static and <init> methods are never in
273 if (target_method()->is_static() || target_method()->name() == vmSymbols::object_initializer_name()) {
274 return false;
275 }
276
277 if (target_method->is_final_method(klass->access_flags())) {
278 // a final method never needs a new entry; final methods can be statically
279 // resolved and they have to be present in the vtable only if they override
280 // a super's method, in which case they re-use its entry
281 allocate_new = false;
282 } else if (klass->is_interface()) {
283 allocate_new = false; // see note below in needs_new_vtable_entry
284 // An interface never allocates new vtable slots, only inherits old ones.
285 // This method will either be assigned its own itable index later,
286 // or be assigned an inherited vtable index in the loop below.
287 target_method()->set_vtable_index(Method::pending_itable_index);
288 }
289
290 // we need a new entry if there is no superclass
291 if (klass->super() == NULL) {
292 return allocate_new;
293 }
294
295 // private methods always have a new entry in the vtable
296 // specification interpretation since classic has
297 // private methods not overriding
298 if (target_method()->is_private()) {
299 return allocate_new;
300 }
301
302 // search through the vtable and update overridden entries
303 // Since check_signature_loaders acquires SystemDictionary_lock
304 // which can block for gc, once we are in this loop, use handles
305 // For classfiles built with >= jdk7, we now look for transitive overrides
306
307 Symbol* name = target_method()->name();
401 }
402 #endif
403 table()[index].set(m);
404 }
405
406 // Find out if a method "m" with superclass "super", loader "classloader" and
407 // name "classname" needs a new vtable entry. Let P be a class package defined
408 // by "classloader" and "classname".
409 // NOTE: The logic used here is very similar to the one used for computing
410 // the vtables indices for a method. We cannot directly use that function because,
411 // we allocate the InstanceKlass at load time, and that requires that the
412 // superclass has been loaded.
413 // However, the vtable entries are filled in at link time, and therefore
414 // the superclass' vtable may not yet have been filled in.
415 bool klassVtable::needs_new_vtable_entry(methodHandle target_method,
416 Klass* super,
417 Handle classloader,
418 Symbol* classname,
419 AccessFlags class_flags,
420 TRAPS) {
421 if (class_flags.is_interface()) {
422 // Interfaces do not use vtables, so there is no point to assigning
423 // a vtable index to any of their methods. If we refrain from doing this,
424 // we can use Method::_vtable_index to hold the itable index
425 return false;
426 }
427
428 if (target_method->is_final_method(class_flags) ||
429 // a final method never needs a new entry; final methods can be statically
430 // resolved and they have to be present in the vtable only if they override
431 // a super's method, in which case they re-use its entry
432 (target_method()->is_static()) ||
433 // static methods don't need to be in vtable
434 (target_method()->name() == vmSymbols::object_initializer_name())
435 // <init> is never called dynamically-bound
436 ) {
437 return false;
438 }
439
440 // we need a new entry if there is no superclass
441 if (super == NULL) {
442 return true;
443 }
444
445 // private methods always have a new entry in the vtable
446 // specification interpretation since classic has
447 // private methods not overriding
448 if (target_method()->is_private()) {
496 }
497 }
498 return true; // found no match; we need a new entry
499 }
500
501 // Support for miranda methods
502
503 // get the vtable index of a miranda method with matching "name" and "signature"
504 int klassVtable::index_of_miranda(Symbol* name, Symbol* signature) {
505 // search from the bottom, might be faster
506 for (int i = (length() - 1); i >= 0; i--) {
507 Method* m = table()[i].method();
508 if (is_miranda_entry_at(i) &&
509 m->name() == name && m->signature() == signature) {
510 return i;
511 }
512 }
513 return Method::invalid_vtable_index;
514 }
515
516 // check if an entry at an index is miranda
517 // requires that method m at entry be declared ("held") by an interface.
518 bool klassVtable::is_miranda_entry_at(int i) {
519 Method* m = method_at(i);
520 Klass* method_holder = m->method_holder();
521 InstanceKlass *mhk = InstanceKlass::cast(method_holder);
522
523 // miranda methods are interface methods in a class's vtable
524 if (mhk->is_interface()) {
525 assert(m->is_public(), "should be public");
526 assert(ik()->implements_interface(method_holder) , "this class should implement the interface");
527 assert(is_miranda(m, ik()->methods(), ik()->super()), "should be a miranda_method");
528 return true;
529 }
530 return false;
531 }
532
533 // check if a method is a miranda method, given a class's methods table and its super
534 // "miranda" means not static, not defined by this class, and not defined
535 // in super unless it is private and therefore inaccessible to this class.
536 // the caller must make sure that the method belongs to an interface implemented by the class
537 bool klassVtable::is_miranda(Method* m, Array<Method*>* class_methods, Klass* super) {
538 if (m->is_static()) {
539 return false;
540 }
541 Symbol* name = m->name();
542 Symbol* signature = m->signature();
543 if (InstanceKlass::find_method(class_methods, name, signature) == NULL) {
544 // did not find it in the method table of the current class
545 if (super == NULL) {
546 // super doesn't exist
547 return true;
548 }
549
550 Method* mo = InstanceKlass::cast(super)->lookup_method(name, signature);
551 if (mo == NULL || mo->access_flags().is_private() ) {
552 // super class hierarchy does not implement it or protection is different
553 return true;
554 }
555 }
556
557 return false;
558 }
559
560 // Scans current_interface_methods for miranda methods that do not
561 // already appear in new_mirandas and are also not defined-and-non-private
562 // in super (superclass). These mirandas are added to all_mirandas if it is
563 // not null; in addition, those that are not duplicates of miranda methods
564 // inherited by super from its interfaces are added to new_mirandas.
565 // Thus, new_mirandas will be the set of mirandas that this class introduces,
566 // all_mirandas will be the set of all mirandas applicable to this class
567 // including all defined in superclasses.
568 void klassVtable::add_new_mirandas_to_lists(
569 GrowableArray<Method*>* new_mirandas, GrowableArray<Method*>* all_mirandas,
570 Array<Method*>* current_interface_methods, Array<Method*>* class_methods,
571 Klass* super) {
572 // iterate thru the current interface's method to see if it a miranda
573 int num_methods = current_interface_methods->length();
574 for (int i = 0; i < num_methods; i++) {
575 Method* im = current_interface_methods->at(i);
576 bool is_duplicate = false;
577 int num_of_current_mirandas = new_mirandas->length();
578 // check for duplicate mirandas in different interfaces we implement
579 for (int j = 0; j < num_of_current_mirandas; j++) {
580 Method* miranda = new_mirandas->at(j);
581 if ((im->name() == miranda->name()) &&
582 (im->signature() == miranda->signature())) {
583 is_duplicate = true;
584 break;
585 }
586 }
587
606 Array<Klass*>* local_interfaces) {
607 assert((new_mirandas->length() == 0) , "current mirandas must be 0");
608
609 // iterate thru the local interfaces looking for a miranda
610 int num_local_ifs = local_interfaces->length();
611 for (int i = 0; i < num_local_ifs; i++) {
612 InstanceKlass *ik = InstanceKlass::cast(local_interfaces->at(i));
613 add_new_mirandas_to_lists(new_mirandas, all_mirandas,
614 ik->methods(), class_methods, super);
615 // iterate thru each local's super interfaces
616 Array<Klass*>* super_ifs = ik->transitive_interfaces();
617 int num_super_ifs = super_ifs->length();
618 for (int j = 0; j < num_super_ifs; j++) {
619 InstanceKlass *sik = InstanceKlass::cast(super_ifs->at(j));
620 add_new_mirandas_to_lists(new_mirandas, all_mirandas,
621 sik->methods(), class_methods, super);
622 }
623 }
624 }
625
626 // Discover miranda methods ("miranda" = "interface abstract, no binding"),
627 // and append them into the vtable starting at index initialized,
628 // return the new value of initialized.
629 int klassVtable::fill_in_mirandas(int initialized) {
630 GrowableArray<Method*> mirandas(20);
631 get_mirandas(&mirandas, NULL, ik()->super(), ik()->methods(),
632 ik()->local_interfaces());
633 for (int i = 0; i < mirandas.length(); i++) {
634 put_method_at(mirandas.at(i), initialized);
635 ++initialized;
636 }
637 return initialized;
638 }
639
640 // Copy this class's vtable to the vtable beginning at start.
641 // Used to copy superclass vtable to prefix of subclass's vtable.
642 void klassVtable::copy_vtable_to(vtableEntry* start) {
643 Copy::disjoint_words((HeapWord*)table(), (HeapWord*)start, _length * vtableEntry::size());
644 }
645
646 #if INCLUDE_JVMTI
647 void klassVtable::adjust_method_entries(Method** old_methods, Method** new_methods,
648 int methods_length, bool * trace_name_printed) {
649 // search the vtable for uses of either obsolete or EMCP methods
650 for (int j = 0; j < methods_length; j++) {
651 Method* old_method = old_methods[j];
652 Method* new_method = new_methods[j];
653
654 // In the vast majority of cases we could get the vtable index
655 // by using: old_method->vtable_index()
656 // However, there are rare cases, eg. sun.awt.X11.XDecoratedPeer.getX()
657 // in sun.awt.X11.XFramePeer where methods occur more than once in the
658 // vtable, so, alas, we must do an exhaustive search.
659 for (int index = 0; index < length(); index++) {
660 if (unchecked_method_at(index) == old_method) {
661 put_method_at(new_method, index);
735 intptr_t* end = klass->end_of_itable();
736
737 _table_offset = (intptr_t*)offset_entry - (intptr_t*)klass();
738 _size_offset_table = (method_entry - ((intptr_t*)offset_entry)) / itableOffsetEntry::size();
739 _size_method_table = (end - method_entry) / itableMethodEntry::size();
740 assert(_table_offset >= 0 && _size_offset_table >= 0 && _size_method_table >= 0, "wrong computation");
741 return;
742 }
743 }
744
745 // The length of the itable was either zero, or it has not yet been initialized.
746 _table_offset = 0;
747 _size_offset_table = 0;
748 _size_method_table = 0;
749 }
750
751 static int initialize_count = 0;
752
753 // Initialization
754 void klassItable::initialize_itable(bool checkconstraints, TRAPS) {
755 if (_klass->is_interface()) {
756 // This needs to go after vtable indexes are assigned but
757 // before implementors need to know the number of itable indexes.
758 assign_itable_indexes_for_interface(_klass());
759 }
760
761 // Cannot be setup doing bootstrapping, interfaces don't have
762 // itables, and klass with only ones entry have empty itables
763 if (Universe::is_bootstrapping() ||
764 _klass->is_interface() ||
765 _klass->itable_length() == itableOffsetEntry::size()) return;
766
767 // There's alway an extra itable entry so we can null-terminate it.
768 guarantee(size_offset_table() >= 1, "too small");
769 int num_interfaces = size_offset_table() - 1;
770 if (num_interfaces > 0) {
771 if (TraceItables) tty->print_cr("%3d: Initializing itables for %s", ++initialize_count,
772 _klass->name()->as_C_string());
773
774
775 // Iterate through all interfaces
776 int i;
777 for(i = 0; i < num_interfaces; i++) {
778 itableOffsetEntry* ioe = offset_entry(i);
779 HandleMark hm(THREAD);
780 KlassHandle interf_h (THREAD, ioe->interface_klass());
781 assert(interf_h() != NULL && ioe->offset() != 0, "bad offset entry in itable");
782 initialize_itable_for_interface(ioe->offset(), interf_h, checkconstraints, CHECK);
783 }
784
785 }
786 // Check that the last entry is empty
787 itableOffsetEntry* ioe = offset_entry(size_offset_table() - 1);
788 guarantee(ioe->interface_klass() == NULL && ioe->offset() == 0, "terminator entry missing");
789 }
790
791
792 inline bool interface_method_needs_itable_index(Method* m) {
793 if (m->is_static()) return false; // e.g., Stream.empty
794 if (m->is_initializer()) return false; // <init> or <clinit>
795 // If an interface redeclares a method from java.lang.Object,
796 // it should already have a vtable index, don't touch it.
797 // e.g., CharSequence.toString (from initialize_vtable)
798 // if (m->has_vtable_index()) return false; // NO!
799 return true;
800 }
801
802 int klassItable::assign_itable_indexes_for_interface(Klass* klass) {
803 // an interface does not have an itable, but its methods need to be numbered
804 if (TraceItables) tty->print_cr("%3d: Initializing itable for interface %s", ++initialize_count,
805 klass->name()->as_C_string());
806 Array<Method*>* methods = InstanceKlass::cast(klass)->methods();
807 int nof_methods = methods->length();
808 int ime_num = 0;
809 for (int i = 0; i < nof_methods; i++) {
810 Method* m = methods->at(i);
811 if (interface_method_needs_itable_index(m)) {
812 assert(!m->is_final_method(), "no final interface methods");
813 // If m is already assigned a vtable index, do not disturb it.
814 if (!m->has_vtable_index()) {
815 assert(m->vtable_index() == Method::pending_itable_index, "set by initialize_vtable");
816 m->set_itable_index(ime_num);
817 // Progress to next itable entry
818 ime_num++;
819 }
820 }
821 }
822 assert(ime_num == method_count_for_interface(klass), "proper sizing");
823 return ime_num;
824 }
825
826 int klassItable::method_count_for_interface(Klass* interf) {
827 assert(interf->oop_is_instance(), "must be");
828 assert(interf->is_interface(), "must be");
829 Array<Method*>* methods = InstanceKlass::cast(interf)->methods();
830 int nof_methods = methods->length();
831 while (nof_methods > 0) {
832 Method* m = methods->at(nof_methods-1);
833 if (m->has_itable_index()) {
834 int length = m->itable_index() + 1;
835 #ifdef ASSERT
836 while (nof_methods = 0) {
837 m = methods->at(--nof_methods);
838 assert(!m->has_itable_index() || m->itable_index() < length, "");
839 }
840 #endif //ASSERT
841 return length; // return the rightmost itable index, plus one
842 }
843 nof_methods -= 1;
844 }
845 // no methods have itable indexes
846 return 0;
847 }
848
849
850 void klassItable::initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS) {
851 Array<Method*>* methods = InstanceKlass::cast(interf_h())->methods();
852 int nof_methods = methods->length();
853 HandleMark hm;
854 assert(nof_methods > 0, "at least one method must exist for interface to be in vtable");
855 Handle interface_loader (THREAD, InstanceKlass::cast(interf_h())->class_loader());
856
857 int ime_count = method_count_for_interface(interf_h());
858 for (int i = 0; i < nof_methods; i++) {
859 Method* m = methods->at(i);
860 methodHandle target;
861 if (m->has_itable_index()) {
862 LinkResolver::lookup_instance_method_in_klasses(target, _klass, m->name(), m->signature(), CHECK);
863 }
864 if (target == NULL || !target->is_public() || target->is_abstract()) {
865 // Entry do not resolve. Leave it empty
866 } else {
867 // Entry did resolve, check loader constraints before initializing
868 // if checkconstraints requested
869 if (checkconstraints) {
870 Handle method_holder_loader (THREAD, target->method_holder()->class_loader());
871 if (method_holder_loader() != interface_loader()) {
872 ResourceMark rm(THREAD);
873 Symbol* failed_type_symbol =
874 SystemDictionary::check_signature_loaders(m->signature(),
875 method_holder_loader,
876 interface_loader,
877 true, CHECK);
878 if (failed_type_symbol != NULL) {
879 const char* msg = "loader constraint violation in interface "
880 "itable initialization: when resolving method \"%s\" the class"
881 " loader (instance of %s) of the current class, %s, "
882 "and the class loader (instance of %s) for interface "
883 "%s have different Class objects for the type %s "
884 "used in the signature";
885 char* sig = target()->name_and_sig_as_C_string();
886 const char* loader1 = SystemDictionary::loader_name(method_holder_loader());
887 char* current = _klass->name()->as_C_string();
888 const char* loader2 = SystemDictionary::loader_name(interface_loader());
889 char* iface = InstanceKlass::cast(interf_h())->name()->as_C_string();
890 char* failed_type_name = failed_type_symbol->as_C_string();
891 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
892 strlen(current) + strlen(loader2) + strlen(iface) +
893 strlen(failed_type_name);
894 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
895 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2,
896 iface, failed_type_name);
897 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
898 }
899 }
900 }
901
902 // ime may have moved during GC so recalculate address
903 int ime_num = m->itable_index();
904 assert(ime_num < ime_count, "oob");
905 itableOffsetEntry::method_entry(_klass(), method_table_offset)[ime_num].initialize(target());
906 }
907 }
908 }
909
910 // Update entry for specific Method*
911 void klassItable::initialize_with_method(Method* m) {
912 itableMethodEntry* ime = method_entry(0);
913 for(int i = 0; i < _size_method_table; i++) {
914 if (ime->method() == m) {
915 ime->initialize(m);
916 }
917 ime++;
918 }
919 }
920
921 #if INCLUDE_JVMTI
922 void klassItable::adjust_method_entries(Method** old_methods, Method** new_methods,
923 int methods_length, bool * trace_name_printed) {
924 // search the itable for uses of either obsolete or EMCP methods
925 for (int j = 0; j < methods_length; j++) {
926 Method* old_method = old_methods[j];
975 Method* m = ime->method();
976 if (m != NULL) {
977 tty->print(" (%5d) ", i);
978 m->access_flags().print_on(tty);
979 tty->print(" -- ");
980 m->print_name(tty);
981 tty->cr();
982 }
983 ime++;
984 }
985 }
986 #endif // INCLUDE_JVMTI
987
988
989 // Setup
990 class InterfaceVisiterClosure : public StackObj {
991 public:
992 virtual void doit(Klass* intf, int method_count) = 0;
993 };
994
995 // Visit all interfaces with at least one itable method
996 void visit_all_interfaces(Array<Klass*>* transitive_intf, InterfaceVisiterClosure *blk) {
997 // Handle array argument
998 for(int i = 0; i < transitive_intf->length(); i++) {
999 Klass* intf = transitive_intf->at(i);
1000 assert(intf->is_interface(), "sanity check");
1001
1002 // Find no. of itable methods
1003 int method_count = 0;
1004 // method_count = klassItable::method_count_for_interface(intf);
1005 Array<Method*>* methods = InstanceKlass::cast(intf)->methods();
1006 if (methods->length() > 0) {
1007 for (int i = methods->length(); --i >= 0; ) {
1008 if (interface_method_needs_itable_index(methods->at(i))) {
1009 method_count++;
1010 }
1011 }
1012 }
1013
1014 // Only count interfaces with at least one method
1015 if (method_count > 0) {
1016 blk->doit(intf, method_count);
1017 }
1018 }
1019 }
1020
1021 class CountInterfacesClosure : public InterfaceVisiterClosure {
1022 private:
1023 int _nof_methods;
1024 int _nof_interfaces;
1025 public:
1026 CountInterfacesClosure() { _nof_methods = 0; _nof_interfaces = 0; }
1027
1028 int nof_methods() const { return _nof_methods; }
1029 int nof_interfaces() const { return _nof_interfaces; }
1030
1088
1089 // Fill-out offset table
1090 itableOffsetEntry* ioe = (itableOffsetEntry*)klass->start_of_itable();
1091 itableMethodEntry* ime = (itableMethodEntry*)(ioe + nof_interfaces);
1092 intptr_t* end = klass->end_of_itable();
1093 assert((oop*)(ime + nof_methods) <= (oop*)klass->start_of_nonstatic_oop_maps(), "wrong offset calculation (1)");
1094 assert((oop*)(end) == (oop*)(ime + nof_methods), "wrong offset calculation (2)");
1095
1096 // Visit all interfaces and initialize itable offset table
1097 SetupItableClosure sic((address)klass(), ioe, ime);
1098 visit_all_interfaces(klass->transitive_interfaces(), &sic);
1099
1100 #ifdef ASSERT
1101 ime = sic.method_entry();
1102 oop* v = (oop*) klass->end_of_itable();
1103 assert( (oop*)(ime) == v, "wrong offset calculation (2)");
1104 #endif
1105 }
1106
1107
1108 // inverse to itable_index
1109 Method* klassItable::method_for_itable_index(Klass* intf, int itable_index) {
1110 assert(InstanceKlass::cast(intf)->is_interface(), "sanity check");
1111 assert(intf->verify_itable_index(itable_index), "");
1112 Array<Method*>* methods = InstanceKlass::cast(intf)->methods();
1113
1114 if (itable_index < 0 || itable_index >= method_count_for_interface(intf))
1115 return NULL; // help caller defend against bad indexes
1116
1117 int index = itable_index;
1118 Method* m = methods->at(index);
1119 int index2 = -1;
1120 while (!m->has_itable_index() ||
1121 (index2 = m->itable_index()) != itable_index) {
1122 assert(index2 < itable_index, "monotonic");
1123 if (++index == methods->length())
1124 return NULL;
1125 m = methods->at(index);
1126 }
1127 assert(m->itable_index() == itable_index, "correct inverse");
1128
1129 return m;
1130 }
1131
1132 void klassVtable::verify(outputStream* st, bool forced) {
1133 // make sure table is initialized
1134 if (!Universe::is_fully_initialized()) return;
1135 #ifndef PRODUCT
1136 // avoid redundant verifies
1137 if (!forced && _verify_count == Universe::verify_count()) return;
1138 _verify_count = Universe::verify_count();
1139 #endif
1140 oop* end_of_obj = (oop*)_klass() + _klass()->size();
1141 oop* end_of_vtable = (oop *)&table()[_length];
1142 if (end_of_vtable > end_of_obj) {
1143 fatal(err_msg("klass %s: klass object too short (vtable extends beyond "
1144 "end)", _klass->internal_name()));
1145 }
1146
1147 for (int i = 0; i < _length; i++) table()[i].verify(this, st);
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