1 /*
2 * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/systemDictionary.hpp"
27 #include "classfile/vmSymbols.hpp"
28 #include "gc/shared/gcLocker.hpp"
29 #include "memory/resourceArea.hpp"
30 #include "memory/universe.inline.hpp"
31 #include "oops/instanceKlass.hpp"
32 #include "oops/klassVtable.hpp"
33 #include "oops/method.hpp"
34 #include "oops/objArrayOop.hpp"
35 #include "oops/oop.inline.hpp"
36 #include "prims/jvmtiRedefineClassesTrace.hpp"
37 #include "runtime/arguments.hpp"
38 #include "runtime/handles.inline.hpp"
39 #include "utilities/copy.hpp"
40
41 inline InstanceKlass* klassVtable::ik() const {
42 Klass* k = _klass();
43 assert(k->oop_is_instance(), "not an InstanceKlass");
44 return (InstanceKlass*)k;
45 }
46
47
48 // this function computes the vtable size (including the size needed for miranda
49 // methods) and the number of miranda methods in this class.
50 // Note on Miranda methods: Let's say there is a class C that implements
51 // interface I, and none of C's superclasses implements I.
52 // Let's say there is an abstract method m in I that neither C
53 // nor any of its super classes implement (i.e there is no method of any access,
54 // with 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++) {
75 assert(methods->at(i)->is_method(), "must be a Method*");
76 methodHandle mh(THREAD, methods->at(i));
77
78 if (needs_new_vtable_entry(mh, super, classloader, classname, class_flags, THREAD)) {
79 vtable_length += vtableEntry::size(); // we need a new entry
80 }
81 }
82
83 GrowableArray<Method*> new_mirandas(20);
84 // compute the number of mirandas methods that must be added to the end
85 get_mirandas(&new_mirandas, all_mirandas, super, methods, NULL, local_interfaces);
86 *num_new_mirandas = new_mirandas.length();
87
88 // Interfaces do not need interface methods in their vtables
89 // This includes miranda methods and during later processing, default methods
90 if (!class_flags.is_interface()) {
91 vtable_length += *num_new_mirandas * vtableEntry::size();
92 }
93
94 if (Universe::is_bootstrapping() && vtable_length == 0) {
95 // array classes don't have their superclass set correctly during
96 // bootstrapping
97 vtable_length = Universe::base_vtable_size();
98 }
99
100 if (super == NULL && vtable_length != Universe::base_vtable_size()) {
101 if (Universe::is_bootstrapping()) {
102 // Someone is attempting to override java.lang.Object incorrectly on the
103 // bootclasspath. The JVM cannot recover from this error including throwing
104 // an exception
105 vm_exit_during_initialization("Incompatible definition of java.lang.Object");
106 } else {
107 // Someone is attempting to redefine java.lang.Object incorrectly. The
108 // only way this should happen is from
109 // SystemDictionary::resolve_from_stream(), which will detect this later
110 // and throw a security exception. So don't assert here to let
111 // the exception occur.
112 vtable_length = Universe::base_vtable_size();
113 }
114 }
115 assert(vtable_length % vtableEntry::size() == 0, "bad vtable length");
116 assert(vtable_length >= Universe::base_vtable_size(), "vtable too small");
117
118 *vtable_length_ret = vtable_length;
119 }
120
121 int klassVtable::index_of(Method* m, int len) const {
122 assert(m->has_vtable_index(), "do not ask this of non-vtable methods");
123 return m->vtable_index();
124 }
125
126 // Copy super class's vtable to the first part (prefix) of this class's vtable,
127 // and return the number of entries copied. Expects that 'super' is the Java
128 // super class (arrays can have "array" super classes that must be skipped).
129 int klassVtable::initialize_from_super(KlassHandle super) {
130 if (super.is_null()) {
131 return 0;
132 } else {
133 // copy methods from superKlass
134 // can't inherit from array class, so must be InstanceKlass
135 assert(super->oop_is_instance(), "must be instance klass");
136 InstanceKlass* sk = (InstanceKlass*)super();
137 klassVtable* superVtable = sk->vtable();
138 assert(superVtable->length() <= _length, "vtable too short");
139 #ifdef ASSERT
140 superVtable->verify(tty, true);
141 #endif
142 superVtable->copy_vtable_to(table());
143 #ifndef PRODUCT
144 if (PrintVtables && Verbose) {
145 ResourceMark rm;
146 tty->print_cr("copy vtable from %s to %s size %d", sk->internal_name(), klass()->internal_name(), _length);
147 }
148 #endif
149 return superVtable->length();
150 }
151 }
152
153 //
154 // Revised lookup semantics introduced 1.3 (Kestrel beta)
155 void klassVtable::initialize_vtable(bool checkconstraints, TRAPS) {
156
157 // Note: Arrays can have intermediate array supers. Use java_super to skip them.
158 KlassHandle super (THREAD, klass()->java_super());
159 int nofNewEntries = 0;
160
161 if (PrintVtables && !klass()->oop_is_array()) {
162 ResourceMark rm(THREAD);
163 tty->print_cr("Initializing: %s", _klass->name()->as_C_string());
164 }
165
166 #ifdef ASSERT
167 oop* end_of_obj = (oop*)_klass() + _klass()->size();
168 oop* end_of_vtable = (oop*)&table()[_length];
169 assert(end_of_vtable <= end_of_obj, "vtable extends beyond end");
170 #endif
171
172 if (Universe::is_bootstrapping()) {
173 // just clear everything
174 for (int i = 0; i < _length; i++) table()[i].clear();
175 return;
176 }
177
178 int super_vtable_len = initialize_from_super(super);
179 if (klass()->oop_is_array()) {
180 assert(super_vtable_len == _length, "arrays shouldn't introduce new methods");
181 } else {
182 assert(_klass->oop_is_instance(), "must be InstanceKlass");
183
184 Array<Method*>* methods = ik()->methods();
185 int len = methods->length();
186 int initialized = super_vtable_len;
187
188 // Check each of this class's methods against super;
189 // if override, replace in copy of super vtable, otherwise append to end
190 for (int i = 0; i < len; i++) {
191 // update_inherited_vtable can stop for gc - ensure using handles
192 HandleMark hm(THREAD);
193 assert(methods->at(i)->is_method(), "must be a Method*");
194 methodHandle mh(THREAD, methods->at(i));
195
196 bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, -1, checkconstraints, CHECK);
197
198 if (needs_new_entry) {
199 put_method_at(mh(), initialized);
200 mh()->set_vtable_index(initialized); // set primary vtable index
201 initialized++;
202 }
203 }
204
205 // update vtable with default_methods
206 Array<Method*>* default_methods = ik()->default_methods();
207 if (default_methods != NULL) {
208 len = default_methods->length();
209 if (len > 0) {
210 Array<int>* def_vtable_indices = NULL;
211 if ((def_vtable_indices = ik()->default_vtable_indices()) == NULL) {
212 def_vtable_indices = ik()->create_new_default_vtable_indices(len, CHECK);
213 } else {
214 assert(def_vtable_indices->length() == len, "reinit vtable len?");
215 }
216 for (int i = 0; i < len; i++) {
217 HandleMark hm(THREAD);
218 assert(default_methods->at(i)->is_method(), "must be a Method*");
219 methodHandle mh(THREAD, default_methods->at(i));
220
221 bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, i, checkconstraints, CHECK);
222
223 // needs new entry
224 if (needs_new_entry) {
225 put_method_at(mh(), initialized);
226 def_vtable_indices->at_put(i, initialized); //set vtable index
227 initialized++;
228 }
229 }
230 }
231 }
232
233 // add miranda methods; it will also return the updated initialized
234 // Interfaces do not need interface methods in their vtables
235 // This includes miranda methods and during later processing, default methods
236 if (!ik()->is_interface()) {
237 initialized = fill_in_mirandas(initialized);
238 }
239
240 // In class hierarchies where the accessibility is not increasing (i.e., going from private ->
241 // package_private -> public/protected), the vtable might actually be smaller than our initial
242 // calculation.
243 assert(initialized <= _length, "vtable initialization failed");
244 for(;initialized < _length; initialized++) {
245 put_method_at(NULL, initialized);
246 }
247 NOT_PRODUCT(verify(tty, true));
248 }
249 }
250
251 // Called for cases where a method does not override its superclass' vtable entry
252 // For bytecodes not produced by javac together it is possible that a method does not override
253 // the superclass's method, but might indirectly override a super-super class's vtable entry
254 // If none found, return a null superk, else return the superk of the method this does override
255 // For public and protected methods: if they override a superclass, they will
256 // also be overridden themselves appropriately.
257 // Private methods do not override and are not overridden.
258 // Package Private methods are trickier:
259 // e.g. P1.A, pub m
260 // P2.B extends A, package private m
261 // P1.C extends B, public m
262 // P1.C.m needs to override P1.A.m and can not override P2.B.m
263 // Therefore: all package private methods need their own vtable entries for
264 // them to be the root of an inheritance overriding decision
265 // Package private methods may also override other vtable entries
266 InstanceKlass* klassVtable::find_transitive_override(InstanceKlass* initialsuper, methodHandle target_method,
267 int vtable_index, Handle target_loader, Symbol* target_classname, Thread * THREAD) {
268 InstanceKlass* superk = initialsuper;
269 while (superk != NULL && superk->super() != NULL) {
270 InstanceKlass* supersuperklass = InstanceKlass::cast(superk->super());
271 klassVtable* ssVtable = supersuperklass->vtable();
272 if (vtable_index < ssVtable->length()) {
273 Method* super_method = ssVtable->method_at(vtable_index);
274 #ifndef PRODUCT
275 Symbol* name= target_method()->name();
276 Symbol* signature = target_method()->signature();
277 assert(super_method->name() == name && super_method->signature() == signature, "vtable entry name/sig mismatch");
278 #endif
279 if (supersuperklass->is_override(super_method, target_loader, target_classname, THREAD)) {
280 #ifndef PRODUCT
281 if (PrintVtables && Verbose) {
282 ResourceMark rm(THREAD);
283 char* sig = target_method()->name_and_sig_as_C_string();
284 tty->print("transitive overriding superclass %s with %s::%s index %d, original flags: ",
285 supersuperklass->internal_name(),
286 _klass->internal_name(), sig, vtable_index);
287 super_method->access_flags().print_on(tty);
288 if (super_method->is_default_method()) {
289 tty->print("default ");
290 }
291 tty->print("overriders flags: ");
292 target_method->access_flags().print_on(tty);
293 if (target_method->is_default_method()) {
294 tty->print("default ");
295 }
296 }
297 #endif /*PRODUCT*/
298 break; // return found superk
299 }
300 } else {
301 // super class has no vtable entry here, stop transitive search
302 superk = (InstanceKlass*)NULL;
303 break;
304 }
305 // if no override found yet, continue to search up
306 superk = InstanceKlass::cast(superk->super());
307 }
308
309 return superk;
310 }
311
312 // Update child's copy of super vtable for overrides
313 // OR return true if a new vtable entry is required.
314 // Only called for InstanceKlass's, i.e. not for arrays
315 // If that changed, could not use _klass as handle for klass
316 bool klassVtable::update_inherited_vtable(InstanceKlass* klass, methodHandle target_method,
317 int super_vtable_len, int default_index,
318 bool checkconstraints, TRAPS) {
319 ResourceMark rm;
320 bool allocate_new = true;
321 assert(klass->oop_is_instance(), "must be InstanceKlass");
322
323 Array<int>* def_vtable_indices = NULL;
324 bool is_default = false;
325 // default methods are concrete methods in superinterfaces which are added to the vtable
326 // with their real method_holder
327 // Since vtable and itable indices share the same storage, don't touch
328 // the default method's real vtable/itable index
329 // default_vtable_indices stores the vtable value relative to this inheritor
330 if (default_index >= 0 ) {
331 is_default = true;
332 def_vtable_indices = klass->default_vtable_indices();
333 assert(def_vtable_indices != NULL, "def vtable alloc?");
334 assert(default_index <= def_vtable_indices->length(), "def vtable len?");
335 } else {
336 assert(klass == target_method()->method_holder(), "caller resp.");
337 // Initialize the method's vtable index to "nonvirtual".
338 // If we allocate a vtable entry, we will update it to a non-negative number.
339 target_method()->set_vtable_index(Method::nonvirtual_vtable_index);
340 }
341
342 // Static and <init> methods are never in
343 if (target_method()->is_static() || target_method()->name() == vmSymbols::object_initializer_name()) {
344 return false;
345 }
346
347 if (target_method->is_final_method(klass->access_flags())) {
348 // a final method never needs a new entry; final methods can be statically
349 // resolved and they have to be present in the vtable only if they override
350 // a super's method, in which case they re-use its entry
351 allocate_new = false;
352 } else if (klass->is_interface()) {
353 allocate_new = false; // see note below in needs_new_vtable_entry
354 // An interface never allocates new vtable slots, only inherits old ones.
355 // This method will either be assigned its own itable index later,
356 // or be assigned an inherited vtable index in the loop below.
357 // default methods inherited by classes store their vtable indices
358 // in the inheritor's default_vtable_indices
359 // default methods inherited by interfaces may already have a
360 // valid itable index, if so, don't change it
361 // overpass methods in an interface will be assigned an itable index later
362 // by an inheriting class
363 if (!is_default || !target_method()->has_itable_index()) {
364 target_method()->set_vtable_index(Method::pending_itable_index);
365 }
366 }
367
368 // we need a new entry if there is no superclass
369 if (klass->super() == NULL) {
370 return allocate_new;
371 }
372
373 // private methods in classes always have a new entry in the vtable
374 // specification interpretation since classic has
375 // private methods not overriding
376 // JDK8 adds private methods in interfaces which require invokespecial
377 if (target_method()->is_private()) {
378 return allocate_new;
379 }
380
381 // search through the vtable and update overridden entries
382 // Since check_signature_loaders acquires SystemDictionary_lock
383 // which can block for gc, once we are in this loop, use handles
384 // For classfiles built with >= jdk7, we now look for transitive overrides
385
386 Symbol* name = target_method()->name();
387 Symbol* signature = target_method()->signature();
388
389 KlassHandle target_klass(THREAD, target_method()->method_holder());
390 if (target_klass == NULL) {
391 target_klass = _klass;
392 }
393
394 Handle target_loader(THREAD, target_klass->class_loader());
395
396 Symbol* target_classname = target_klass->name();
397 for(int i = 0; i < super_vtable_len; i++) {
398 Method* super_method = method_at(i);
399 // Check if method name matches
400 if (super_method->name() == name && super_method->signature() == signature) {
401
402 // get super_klass for method_holder for the found method
403 InstanceKlass* super_klass = super_method->method_holder();
404
405 // private methods are also never overridden
406 if (!super_method->is_private() &&
407 (is_default
408 || ((super_klass->is_override(super_method, target_loader, target_classname, THREAD))
409 || ((klass->major_version() >= VTABLE_TRANSITIVE_OVERRIDE_VERSION)
410 && ((super_klass = find_transitive_override(super_klass,
411 target_method, i, target_loader,
412 target_classname, THREAD))
413 != (InstanceKlass*)NULL)))))
414 {
415 // Package private methods always need a new entry to root their own
416 // overriding. They may also override other methods.
417 if (!target_method()->is_package_private()) {
418 allocate_new = false;
419 }
420
421 if (checkconstraints) {
422 // Override vtable entry if passes loader constraint check
423 // if loader constraint checking requested
424 // No need to visit his super, since he and his super
425 // have already made any needed loader constraints.
426 // Since loader constraints are transitive, it is enough
427 // to link to the first super, and we get all the others.
428 Handle super_loader(THREAD, super_klass->class_loader());
429
430 if (target_loader() != super_loader()) {
431 ResourceMark rm(THREAD);
432 Symbol* failed_type_symbol =
433 SystemDictionary::check_signature_loaders(signature, target_loader,
434 super_loader, true,
435 CHECK_(false));
436 if (failed_type_symbol != NULL) {
437 const char* msg = "loader constraint violation: when resolving "
438 "overridden method \"%s\" the class loader (instance"
439 " of %s) of the current class, %s, and its superclass loader "
440 "(instance of %s), have different Class objects for the type "
441 "%s used in the signature";
442 char* sig = target_method()->name_and_sig_as_C_string();
443 const char* loader1 = SystemDictionary::loader_name(target_loader());
444 char* current = target_klass->name()->as_C_string();
445 const char* loader2 = SystemDictionary::loader_name(super_loader());
446 char* failed_type_name = failed_type_symbol->as_C_string();
447 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
448 strlen(current) + strlen(loader2) + strlen(failed_type_name);
449 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
450 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2,
451 failed_type_name);
452 THROW_MSG_(vmSymbols::java_lang_LinkageError(), buf, false);
453 }
454 }
455 }
456
457 put_method_at(target_method(), i);
458 if (!is_default) {
459 target_method()->set_vtable_index(i);
460 } else {
461 if (def_vtable_indices != NULL) {
462 def_vtable_indices->at_put(default_index, i);
463 }
464 assert(super_method->is_default_method() || super_method->is_overpass()
465 || super_method->is_abstract(), "default override error");
466 }
467
468
469 #ifndef PRODUCT
470 if (PrintVtables && Verbose) {
471 ResourceMark rm(THREAD);
472 char* sig = target_method()->name_and_sig_as_C_string();
473 tty->print("overriding with %s::%s index %d, original flags: ",
474 target_klass->internal_name(), sig, i);
475 super_method->access_flags().print_on(tty);
476 if (super_method->is_default_method()) {
477 tty->print("default ");
478 }
479 if (super_method->is_overpass()) {
480 tty->print("overpass");
481 }
482 tty->print("overriders flags: ");
483 target_method->access_flags().print_on(tty);
484 if (target_method->is_default_method()) {
485 tty->print("default ");
486 }
487 if (target_method->is_overpass()) {
488 tty->print("overpass");
489 }
490 tty->cr();
491 }
492 #endif /*PRODUCT*/
493 } else {
494 // allocate_new = true; default. We might override one entry,
495 // but not override another. Once we override one, not need new
496 #ifndef PRODUCT
497 if (PrintVtables && Verbose) {
498 ResourceMark rm(THREAD);
499 char* sig = target_method()->name_and_sig_as_C_string();
500 tty->print("NOT overriding with %s::%s index %d, original flags: ",
501 target_klass->internal_name(), sig,i);
502 super_method->access_flags().print_on(tty);
503 if (super_method->is_default_method()) {
504 tty->print("default ");
505 }
506 if (super_method->is_overpass()) {
507 tty->print("overpass");
508 }
509 tty->print("overriders flags: ");
510 target_method->access_flags().print_on(tty);
511 if (target_method->is_default_method()) {
512 tty->print("default ");
513 }
514 if (target_method->is_overpass()) {
515 tty->print("overpass");
516 }
517 tty->cr();
518 }
519 #endif /*PRODUCT*/
520 }
521 }
522 }
523 return allocate_new;
524 }
525
526 void klassVtable::put_method_at(Method* m, int index) {
527 #ifndef PRODUCT
528 if (PrintVtables && Verbose) {
529 ResourceMark rm;
530 const char* sig = (m != NULL) ? m->name_and_sig_as_C_string() : "<NULL>";
531 tty->print("adding %s at index %d, flags: ", sig, index);
532 if (m != NULL) {
533 m->access_flags().print_on(tty);
534 if (m->is_default_method()) {
535 tty->print("default ");
536 }
537 if (m->is_overpass()) {
538 tty->print("overpass");
539 }
540 }
541 tty->cr();
542 }
543 #endif
544 table()[index].set(m);
545 }
546
547 // Find out if a method "m" with superclass "super", loader "classloader" and
548 // name "classname" needs a new vtable entry. Let P be a class package defined
549 // by "classloader" and "classname".
550 // NOTE: The logic used here is very similar to the one used for computing
551 // the vtables indices for a method. We cannot directly use that function because,
552 // we allocate the InstanceKlass at load time, and that requires that the
553 // superclass has been loaded.
554 // However, the vtable entries are filled in at link time, and therefore
555 // the superclass' vtable may not yet have been filled in.
556 bool klassVtable::needs_new_vtable_entry(methodHandle target_method,
557 Klass* super,
558 Handle classloader,
559 Symbol* classname,
560 AccessFlags class_flags,
561 TRAPS) {
562 if (class_flags.is_interface()) {
563 // Interfaces do not use vtables, except for java.lang.Object methods,
564 // so there is no point to assigning
565 // a vtable index to any of their local methods. If we refrain from doing this,
566 // we can use Method::_vtable_index to hold the itable index
567 return false;
568 }
569
570 if (target_method->is_final_method(class_flags) ||
571 // a final method never needs a new entry; final methods can be statically
572 // resolved and they have to be present in the vtable only if they override
573 // a super's method, in which case they re-use its entry
574 (target_method()->is_static()) ||
575 // static methods don't need to be in vtable
576 (target_method()->name() == vmSymbols::object_initializer_name())
577 // <init> is never called dynamically-bound
578 ) {
579 return false;
580 }
581
582 // Concrete interface methods do not need new entries, they override
583 // abstract method entries using default inheritance rules
584 if (target_method()->method_holder() != NULL &&
585 target_method()->method_holder()->is_interface() &&
586 !target_method()->is_abstract() ) {
587 return false;
588 }
589
590 // we need a new entry if there is no superclass
591 if (super == NULL) {
592 return true;
593 }
594
595 // private methods in classes always have a new entry in the vtable
596 // specification interpretation since classic has
597 // private methods not overriding
598 // JDK8 adds private methods in interfaces which require invokespecial
599 if (target_method()->is_private()) {
600 return true;
601 }
602
603 // Package private methods always need a new entry to root their own
604 // overriding. This allows transitive overriding to work.
605 if (target_method()->is_package_private()) {
606 return true;
607 }
608
609 // search through the super class hierarchy to see if we need
610 // a new entry
611 ResourceMark rm;
612 Symbol* name = target_method()->name();
613 Symbol* signature = target_method()->signature();
614 Klass* k = super;
615 Method* super_method = NULL;
616 InstanceKlass *holder = NULL;
617 Method* recheck_method = NULL;
618 while (k != NULL) {
619 // lookup through the hierarchy for a method with matching name and sign.
620 super_method = InstanceKlass::cast(k)->lookup_method(name, signature);
621 if (super_method == NULL) {
622 break; // we still have to search for a matching miranda method
623 }
624 // get the class holding the matching method
625 // make sure you use that class for is_override
626 InstanceKlass* superk = super_method->method_holder();
627 // we want only instance method matches
628 // pretend private methods are not in the super vtable
629 // since we do override around them: e.g. a.m pub/b.m private/c.m pub,
630 // ignore private, c.m pub does override a.m pub
631 // For classes that were not javac'd together, we also do transitive overriding around
632 // methods that have less accessibility
633 if ((!super_method->is_static()) &&
634 (!super_method->is_private())) {
635 if (superk->is_override(super_method, classloader, classname, THREAD)) {
636 return false;
637 // else keep looking for transitive overrides
638 }
639 }
640
641 // Start with lookup result and continue to search up
642 k = superk->super(); // haven't found an override match yet; continue to look
643 }
644
645 // if the target method is public or protected it may have a matching
646 // miranda method in the super, whose entry it should re-use.
647 // Actually, to handle cases that javac would not generate, we need
648 // this check for all access permissions.
649 InstanceKlass *sk = InstanceKlass::cast(super);
650 if (sk->has_miranda_methods()) {
651 if (sk->lookup_method_in_all_interfaces(name, signature, Klass::find_defaults) != NULL) {
652 return false; // found a matching miranda; we do not need a new entry
653 }
654 }
655 return true; // found no match; we need a new entry
656 }
657
658 // Support for miranda methods
659
660 // get the vtable index of a miranda method with matching "name" and "signature"
661 int klassVtable::index_of_miranda(Symbol* name, Symbol* signature) {
662 // search from the bottom, might be faster
663 for (int i = (length() - 1); i >= 0; i--) {
664 Method* m = table()[i].method();
665 if (is_miranda_entry_at(i) &&
666 m->name() == name && m->signature() == signature) {
667 return i;
668 }
669 }
670 return Method::invalid_vtable_index;
671 }
672
673 // check if an entry at an index is miranda
674 // requires that method m at entry be declared ("held") by an interface.
675 bool klassVtable::is_miranda_entry_at(int i) {
676 Method* m = method_at(i);
677 Klass* method_holder = m->method_holder();
678 InstanceKlass *mhk = InstanceKlass::cast(method_holder);
679
680 // miranda methods are public abstract instance interface methods in a class's vtable
681 if (mhk->is_interface()) {
682 assert(m->is_public(), "should be public");
683 assert(ik()->implements_interface(method_holder) , "this class should implement the interface");
684 if (is_miranda(m, ik()->methods(), ik()->default_methods(), ik()->super())) {
685 return true;
686 }
687 }
688 return false;
689 }
690
691 // Check if a method is a miranda method, given a class's methods array,
692 // its default_method table and its super class.
693 // "Miranda" means an abstract non-private method that would not be
694 // overridden for the local class.
695 // A "miranda" method should only include non-private interface
696 // instance methods, i.e. not private methods, not static methods,
697 // not default methods (concrete interface methods), not overpass methods.
698 // If a given class already has a local (including overpass) method, a
699 // default method, or any of its superclasses has the same which would have
700 // overridden an abstract method, then this is not a miranda method.
701 //
702 // Miranda methods are checked multiple times.
703 // Pass 1: during class load/class file parsing: before vtable size calculation:
704 // include superinterface abstract and default methods (non-private instance).
705 // We include potential default methods to give them space in the vtable.
706 // During the first run, the current instanceKlass has not yet been
707 // created, the superclasses and superinterfaces do have instanceKlasses
708 // but may not have vtables, the default_methods list is empty, no overpasses.
709 // This is seen by default method creation.
710 //
711 // Pass 2: recalculated during vtable initialization: only include abstract methods.
712 // The goal of pass 2 is to walk through the superinterfaces to see if any of
713 // the superinterface methods (which were all abstract pre-default methods)
714 // need to be added to the vtable.
715 // With the addition of default methods, we have three new challenges:
716 // overpasses, static interface methods and private interface methods.
717 // Static and private interface methods do not get added to the vtable and
718 // are not seen by the method resolution process, so we skip those.
719 // Overpass methods are already in the vtable, so vtable lookup will
720 // find them and we don't need to add a miranda method to the end of
721 // the vtable. So we look for overpass methods and if they are found we
722 // return false. Note that we inherit our superclasses vtable, so
723 // the superclass' search also needs to use find_overpass so that if
724 // one is found we return false.
725 // False means - we don't need a miranda method added to the vtable.
726 //
727 // During the second run, default_methods is set up, so concrete methods from
728 // superinterfaces with matching names/signatures to default_methods are already
729 // in the default_methods list and do not need to be appended to the vtable
730 // as mirandas. Abstract methods may already have been handled via
731 // overpasses - either local or superclass overpasses, which may be
732 // in the vtable already.
733 //
734 // Pass 3: They are also checked by link resolution and selection,
735 // for invocation on a method (not interface method) reference that
736 // resolves to a method with an interface as its method_holder.
737 // Used as part of walking from the bottom of the vtable to find
738 // the vtable index for the miranda method.
739 //
740 // Part of the Miranda Rights in the US mean that if you do not have
741 // an attorney one will be appointed for you.
742 bool klassVtable::is_miranda(Method* m, Array<Method*>* class_methods,
743 Array<Method*>* default_methods, Klass* super) {
744 if (m->is_static() || m->is_private() || m->is_overpass()) {
745 return false;
746 }
747 Symbol* name = m->name();
748 Symbol* signature = m->signature();
749
750 // First look in local methods to see if already covered
751 if (InstanceKlass::find_local_method(class_methods, name, signature,
752 Klass::find_overpass, Klass::skip_static, Klass::skip_private) != NULL)
753 {
754 return false;
755 }
756
757 // Check local default methods
758 if ((default_methods != NULL) &&
759 (InstanceKlass::find_method(default_methods, name, signature) != NULL))
760 {
761 return false;
762 }
763
764 InstanceKlass* cursuper;
765 // Iterate on all superclasses, which should have instanceKlasses
766 // Note that we explicitly look for overpasses at each level.
767 // Overpasses may or may not exist for supers for pass 1,
768 // they should have been created for pass 2 and later.
769
770 for (cursuper = InstanceKlass::cast(super); cursuper != NULL; cursuper = (InstanceKlass*)cursuper->super())
771 {
772 if (cursuper->find_local_method(name, signature,
773 Klass::find_overpass, Klass::skip_static, Klass::skip_private) != NULL) {
774 return false;
775 }
776 }
777
778 return true;
779 }
780
781 // Scans current_interface_methods for miranda methods that do not
782 // already appear in new_mirandas, or default methods, and are also not defined-and-non-private
783 // in super (superclass). These mirandas are added to all_mirandas if it is
784 // not null; in addition, those that are not duplicates of miranda methods
785 // inherited by super from its interfaces are added to new_mirandas.
786 // Thus, new_mirandas will be the set of mirandas that this class introduces,
787 // all_mirandas will be the set of all mirandas applicable to this class
788 // including all defined in superclasses.
789 void klassVtable::add_new_mirandas_to_lists(
790 GrowableArray<Method*>* new_mirandas, GrowableArray<Method*>* all_mirandas,
791 Array<Method*>* current_interface_methods, Array<Method*>* class_methods,
792 Array<Method*>* default_methods, Klass* super) {
793
794 // iterate thru the current interface's method to see if it a miranda
795 int num_methods = current_interface_methods->length();
796 for (int i = 0; i < num_methods; i++) {
797 Method* im = current_interface_methods->at(i);
798 bool is_duplicate = false;
799 int num_of_current_mirandas = new_mirandas->length();
800 // check for duplicate mirandas in different interfaces we implement
801 for (int j = 0; j < num_of_current_mirandas; j++) {
802 Method* miranda = new_mirandas->at(j);
803 if ((im->name() == miranda->name()) &&
804 (im->signature() == miranda->signature())) {
805 is_duplicate = true;
806 break;
807 }
808 }
809
810 if (!is_duplicate) { // we don't want duplicate miranda entries in the vtable
811 if (is_miranda(im, class_methods, default_methods, super)) { // is it a miranda at all?
812 InstanceKlass *sk = InstanceKlass::cast(super);
813 // check if it is a duplicate of a super's miranda
814 if (sk->lookup_method_in_all_interfaces(im->name(), im->signature(), Klass::find_defaults) == NULL) {
815 new_mirandas->append(im);
816 }
817 if (all_mirandas != NULL) {
818 all_mirandas->append(im);
819 }
820 }
821 }
822 }
823 }
824
825 void klassVtable::get_mirandas(GrowableArray<Method*>* new_mirandas,
826 GrowableArray<Method*>* all_mirandas,
827 Klass* super, Array<Method*>* class_methods,
828 Array<Method*>* default_methods,
829 Array<Klass*>* local_interfaces) {
830 assert((new_mirandas->length() == 0) , "current mirandas must be 0");
831
832 // iterate thru the local interfaces looking for a miranda
833 int num_local_ifs = local_interfaces->length();
834 for (int i = 0; i < num_local_ifs; i++) {
835 InstanceKlass *ik = InstanceKlass::cast(local_interfaces->at(i));
836 add_new_mirandas_to_lists(new_mirandas, all_mirandas,
837 ik->methods(), class_methods,
838 default_methods, super);
839 // iterate thru each local's super interfaces
840 Array<Klass*>* super_ifs = ik->transitive_interfaces();
841 int num_super_ifs = super_ifs->length();
842 for (int j = 0; j < num_super_ifs; j++) {
843 InstanceKlass *sik = InstanceKlass::cast(super_ifs->at(j));
844 add_new_mirandas_to_lists(new_mirandas, all_mirandas,
845 sik->methods(), class_methods,
846 default_methods, super);
847 }
848 }
849 }
850
851 // Discover miranda methods ("miranda" = "interface abstract, no binding"),
852 // and append them into the vtable starting at index initialized,
853 // return the new value of initialized.
854 // Miranda methods use vtable entries, but do not get assigned a vtable_index
855 // The vtable_index is discovered by searching from the end of the vtable
856 int klassVtable::fill_in_mirandas(int initialized) {
857 GrowableArray<Method*> mirandas(20);
858 get_mirandas(&mirandas, NULL, ik()->super(), ik()->methods(),
859 ik()->default_methods(), ik()->local_interfaces());
860 for (int i = 0; i < mirandas.length(); i++) {
861 if (PrintVtables && Verbose) {
862 Method* meth = mirandas.at(i);
863 ResourceMark rm(Thread::current());
864 if (meth != NULL) {
865 char* sig = meth->name_and_sig_as_C_string();
866 tty->print("fill in mirandas with %s index %d, flags: ",
867 sig, initialized);
868 meth->access_flags().print_on(tty);
869 if (meth->is_default_method()) {
870 tty->print("default ");
871 }
872 tty->cr();
873 }
874 }
875 put_method_at(mirandas.at(i), initialized);
876 ++initialized;
877 }
878 return initialized;
879 }
880
881 // Copy this class's vtable to the vtable beginning at start.
882 // Used to copy superclass vtable to prefix of subclass's vtable.
883 void klassVtable::copy_vtable_to(vtableEntry* start) {
884 Copy::disjoint_words((HeapWord*)table(), (HeapWord*)start, _length * vtableEntry::size());
885 }
886
887 #if INCLUDE_JVMTI
888 bool klassVtable::adjust_default_method(int vtable_index, Method* old_method, Method* new_method) {
889 // If old_method is default, find this vtable index in default_vtable_indices
890 // and replace that method in the _default_methods list
891 bool updated = false;
892
893 Array<Method*>* default_methods = ik()->default_methods();
894 if (default_methods != NULL) {
895 int len = default_methods->length();
896 for (int idx = 0; idx < len; idx++) {
897 if (vtable_index == ik()->default_vtable_indices()->at(idx)) {
898 if (default_methods->at(idx) == old_method) {
899 default_methods->at_put(idx, new_method);
900 updated = true;
901 }
902 break;
903 }
904 }
905 }
906 return updated;
907 }
908
909 // search the vtable for uses of either obsolete or EMCP methods
910 void klassVtable::adjust_method_entries(InstanceKlass* holder, bool * trace_name_printed) {
911 int prn_enabled = 0;
912 for (int index = 0; index < length(); index++) {
913 Method* old_method = unchecked_method_at(index);
914 if (old_method == NULL || old_method->method_holder() != holder || !old_method->is_old()) {
915 continue; // skip uninteresting entries
916 }
917 assert(!old_method->is_deleted(), "vtable methods may not be deleted");
918
919 Method* new_method = holder->method_with_idnum(old_method->orig_method_idnum());
920
921 assert(new_method != NULL, "method_with_idnum() should not be NULL");
922 assert(old_method != new_method, "sanity check");
923
924 put_method_at(new_method, index);
925 // For default methods, need to update the _default_methods array
926 // which can only have one method entry for a given signature
927 bool updated_default = false;
928 if (old_method->is_default_method()) {
929 updated_default = adjust_default_method(index, old_method, new_method);
930 }
931
932 if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
933 if (!(*trace_name_printed)) {
934 // RC_TRACE_MESG macro has an embedded ResourceMark
935 RC_TRACE_MESG(("adjust: klassname=%s for methods from name=%s",
936 klass()->external_name(),
937 old_method->method_holder()->external_name()));
938 *trace_name_printed = true;
939 }
940 // RC_TRACE macro has an embedded ResourceMark
941 RC_TRACE(0x00100000, ("vtable method update: %s(%s), updated default = %s",
942 new_method->name()->as_C_string(),
943 new_method->signature()->as_C_string(),
944 updated_default ? "true" : "false"));
945 }
946 }
947 }
948
949 // a vtable should never contain old or obsolete methods
950 bool klassVtable::check_no_old_or_obsolete_entries() {
951 for (int i = 0; i < length(); i++) {
952 Method* m = unchecked_method_at(i);
953 if (m != NULL &&
954 (NOT_PRODUCT(!m->is_valid() ||) m->is_old() || m->is_obsolete())) {
955 return false;
956 }
957 }
958 return true;
959 }
960
961 void klassVtable::dump_vtable() {
962 tty->print_cr("vtable dump --");
963 for (int i = 0; i < length(); i++) {
964 Method* m = unchecked_method_at(i);
965 if (m != NULL) {
966 tty->print(" (%5d) ", i);
967 m->access_flags().print_on(tty);
968 if (m->is_default_method()) {
969 tty->print("default ");
970 }
971 if (m->is_overpass()) {
972 tty->print("overpass");
973 }
974 tty->print(" -- ");
975 m->print_name(tty);
976 tty->cr();
977 }
978 }
979 }
980 #endif // INCLUDE_JVMTI
981
982 // CDS/RedefineClasses support - clear vtables so they can be reinitialized
983 void klassVtable::clear_vtable() {
984 for (int i = 0; i < _length; i++) table()[i].clear();
985 }
986
987 bool klassVtable::is_initialized() {
988 return _length == 0 || table()[0].method() != NULL;
989 }
990
991 //-----------------------------------------------------------------------------------------
992 // Itable code
993
994 // Initialize a itableMethodEntry
995 void itableMethodEntry::initialize(Method* m) {
996 if (m == NULL) return;
997
998 _method = m;
999 }
1000
1001 klassItable::klassItable(instanceKlassHandle klass) {
1002 _klass = klass;
1003
1004 if (klass->itable_length() > 0) {
1005 itableOffsetEntry* offset_entry = (itableOffsetEntry*)klass->start_of_itable();
1006 if (offset_entry != NULL && offset_entry->interface_klass() != NULL) { // Check that itable is initialized
1007 // First offset entry points to the first method_entry
1008 intptr_t* method_entry = (intptr_t *)(((address)klass()) + offset_entry->offset());
1009 intptr_t* end = klass->end_of_itable();
1010
1011 _table_offset = (intptr_t*)offset_entry - (intptr_t*)klass();
1012 _size_offset_table = (method_entry - ((intptr_t*)offset_entry)) / itableOffsetEntry::size();
1013 _size_method_table = (end - method_entry) / itableMethodEntry::size();
1014 assert(_table_offset >= 0 && _size_offset_table >= 0 && _size_method_table >= 0, "wrong computation");
1015 return;
1016 }
1017 }
1018
1019 // The length of the itable was either zero, or it has not yet been initialized.
1020 _table_offset = 0;
1021 _size_offset_table = 0;
1022 _size_method_table = 0;
1023 }
1024
1025 static int initialize_count = 0;
1026
1027 // Initialization
1028 void klassItable::initialize_itable(bool checkconstraints, TRAPS) {
1029 if (_klass->is_interface()) {
1030 // This needs to go after vtable indices are assigned but
1031 // before implementors need to know the number of itable indices.
1032 assign_itable_indices_for_interface(_klass());
1033 }
1034
1035 // Cannot be setup doing bootstrapping, interfaces don't have
1036 // itables, and klass with only ones entry have empty itables
1037 if (Universe::is_bootstrapping() ||
1038 _klass->is_interface() ||
1039 _klass->itable_length() == itableOffsetEntry::size()) return;
1040
1041 // There's alway an extra itable entry so we can null-terminate it.
1042 guarantee(size_offset_table() >= 1, "too small");
1043 int num_interfaces = size_offset_table() - 1;
1044 if (num_interfaces > 0) {
1045 if (TraceItables) tty->print_cr("%3d: Initializing itables for %s", ++initialize_count,
1046 _klass->name()->as_C_string());
1047
1048
1049 // Iterate through all interfaces
1050 int i;
1051 for(i = 0; i < num_interfaces; i++) {
1052 itableOffsetEntry* ioe = offset_entry(i);
1053 HandleMark hm(THREAD);
1054 KlassHandle interf_h (THREAD, ioe->interface_klass());
1055 assert(interf_h() != NULL && ioe->offset() != 0, "bad offset entry in itable");
1056 initialize_itable_for_interface(ioe->offset(), interf_h, checkconstraints, CHECK);
1057 }
1058
1059 }
1060 // Check that the last entry is empty
1061 itableOffsetEntry* ioe = offset_entry(size_offset_table() - 1);
1062 guarantee(ioe->interface_klass() == NULL && ioe->offset() == 0, "terminator entry missing");
1063 }
1064
1065
1066 inline bool interface_method_needs_itable_index(Method* m) {
1067 if (m->is_static()) return false; // e.g., Stream.empty
1068 if (m->is_initializer()) return false; // <init> or <clinit>
1069 // If an interface redeclares a method from java.lang.Object,
1070 // it should already have a vtable index, don't touch it.
1071 // e.g., CharSequence.toString (from initialize_vtable)
1072 // if (m->has_vtable_index()) return false; // NO!
1073 return true;
1074 }
1075
1076 int klassItable::assign_itable_indices_for_interface(Klass* klass) {
1077 // an interface does not have an itable, but its methods need to be numbered
1078 if (TraceItables) tty->print_cr("%3d: Initializing itable indices for interface %s", ++initialize_count,
1079 klass->name()->as_C_string());
1080 Array<Method*>* methods = InstanceKlass::cast(klass)->methods();
1081 int nof_methods = methods->length();
1082 int ime_num = 0;
1083 for (int i = 0; i < nof_methods; i++) {
1084 Method* m = methods->at(i);
1085 if (interface_method_needs_itable_index(m)) {
1086 assert(!m->is_final_method(), "no final interface methods");
1087 // If m is already assigned a vtable index, do not disturb it.
1088 if (TraceItables && Verbose) {
1089 ResourceMark rm;
1090 const char* sig = (m != NULL) ? m->name_and_sig_as_C_string() : "<NULL>";
1091 if (m->has_vtable_index()) {
1092 tty->print("vtable index %d for method: %s, flags: ", m->vtable_index(), sig);
1093 } else {
1094 tty->print("itable index %d for method: %s, flags: ", ime_num, sig);
1095 }
1096 if (m != NULL) {
1097 m->access_flags().print_on(tty);
1098 if (m->is_default_method()) {
1099 tty->print("default ");
1100 }
1101 if (m->is_overpass()) {
1102 tty->print("overpass");
1103 }
1104 }
1105 tty->cr();
1106 }
1107 if (!m->has_vtable_index()) {
1108 assert(m->vtable_index() == Method::pending_itable_index, "set by initialize_vtable");
1109 m->set_itable_index(ime_num);
1110 // Progress to next itable entry
1111 ime_num++;
1112 }
1113 }
1114 }
1115 assert(ime_num == method_count_for_interface(klass), "proper sizing");
1116 return ime_num;
1117 }
1118
1119 int klassItable::method_count_for_interface(Klass* interf) {
1120 assert(interf->oop_is_instance(), "must be");
1121 assert(interf->is_interface(), "must be");
1122 Array<Method*>* methods = InstanceKlass::cast(interf)->methods();
1123 int nof_methods = methods->length();
1124 int length = 0;
1125 while (nof_methods > 0) {
1126 Method* m = methods->at(nof_methods-1);
1127 if (m->has_itable_index()) {
1128 length = m->itable_index() + 1;
1129 break;
1130 }
1131 nof_methods -= 1;
1132 }
1133 #ifdef ASSERT
1134 int nof_methods_copy = nof_methods;
1135 while (nof_methods_copy > 0) {
1136 Method* mm = methods->at(--nof_methods_copy);
1137 assert(!mm->has_itable_index() || mm->itable_index() < length, "");
1138 }
1139 #endif //ASSERT
1140 // return the rightmost itable index, plus one; or 0 if no methods have
1141 // itable indices
1142 return length;
1143 }
1144
1145
1146 void klassItable::initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS) {
1147 Array<Method*>* methods = InstanceKlass::cast(interf_h())->methods();
1148 int nof_methods = methods->length();
1149 HandleMark hm;
1150 assert(nof_methods > 0, "at least one method must exist for interface to be in vtable");
1151 Handle interface_loader (THREAD, InstanceKlass::cast(interf_h())->class_loader());
1152
1153 int ime_count = method_count_for_interface(interf_h());
1154 for (int i = 0; i < nof_methods; i++) {
1155 Method* m = methods->at(i);
1156 methodHandle target;
1157 if (m->has_itable_index()) {
1158 // This search must match the runtime resolution, i.e. selection search for invokeinterface
1159 // to correctly enforce loader constraints for interface method inheritance
1160 target = LinkResolver::lookup_instance_method_in_klasses(_klass, m->name(), m->signature(), CHECK);
1161 }
1162 if (target == NULL || !target->is_public() || target->is_abstract()) {
1163 // Entry does not resolve. Leave it empty for AbstractMethodError.
1164 if (!(target == NULL) && !target->is_public()) {
1165 // Stuff an IllegalAccessError throwing method in there instead.
1166 itableOffsetEntry::method_entry(_klass(), method_table_offset)[m->itable_index()].
1167 initialize(Universe::throw_illegal_access_error());
1168 }
1169 } else {
1170 // Entry did resolve, check loader constraints before initializing
1171 // if checkconstraints requested
1172 if (checkconstraints) {
1173 Handle method_holder_loader (THREAD, target->method_holder()->class_loader());
1174 if (method_holder_loader() != interface_loader()) {
1175 ResourceMark rm(THREAD);
1176 Symbol* failed_type_symbol =
1177 SystemDictionary::check_signature_loaders(m->signature(),
1178 method_holder_loader,
1179 interface_loader,
1180 true, CHECK);
1181 if (failed_type_symbol != NULL) {
1182 const char* msg = "loader constraint violation in interface "
1183 "itable initialization: when resolving method \"%s\" the class"
1184 " loader (instance of %s) of the current class, %s, "
1185 "and the class loader (instance of %s) for interface "
1186 "%s have different Class objects for the type %s "
1187 "used in the signature";
1188 char* sig = target()->name_and_sig_as_C_string();
1189 const char* loader1 = SystemDictionary::loader_name(method_holder_loader());
1190 char* current = _klass->name()->as_C_string();
1191 const char* loader2 = SystemDictionary::loader_name(interface_loader());
1192 char* iface = InstanceKlass::cast(interf_h())->name()->as_C_string();
1193 char* failed_type_name = failed_type_symbol->as_C_string();
1194 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
1195 strlen(current) + strlen(loader2) + strlen(iface) +
1196 strlen(failed_type_name);
1197 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
1198 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2,
1199 iface, failed_type_name);
1200 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
1201 }
1202 }
1203 }
1204
1205 // ime may have moved during GC so recalculate address
1206 int ime_num = m->itable_index();
1207 assert(ime_num < ime_count, "oob");
1208 itableOffsetEntry::method_entry(_klass(), method_table_offset)[ime_num].initialize(target());
1209 if (TraceItables && Verbose) {
1210 ResourceMark rm(THREAD);
1211 if (target() != NULL) {
1212 char* sig = target()->name_and_sig_as_C_string();
1213 tty->print("interface: %s, ime_num: %d, target: %s, method_holder: %s ",
1214 interf_h()->internal_name(), ime_num, sig,
1215 target()->method_holder()->internal_name());
1216 tty->print("target_method flags: ");
1217 target()->access_flags().print_on(tty);
1218 if (target()->is_default_method()) {
1219 tty->print("default ");
1220 }
1221 tty->cr();
1222 }
1223 }
1224 }
1225 }
1226 }
1227
1228 // Update entry for specific Method*
1229 void klassItable::initialize_with_method(Method* m) {
1230 itableMethodEntry* ime = method_entry(0);
1231 for(int i = 0; i < _size_method_table; i++) {
1232 if (ime->method() == m) {
1233 ime->initialize(m);
1234 }
1235 ime++;
1236 }
1237 }
1238
1239 #if INCLUDE_JVMTI
1240 // search the itable for uses of either obsolete or EMCP methods
1241 void klassItable::adjust_method_entries(InstanceKlass* holder, bool * trace_name_printed) {
1242
1243 itableMethodEntry* ime = method_entry(0);
1244 for (int i = 0; i < _size_method_table; i++, ime++) {
1245 Method* old_method = ime->method();
1246 if (old_method == NULL || old_method->method_holder() != holder || !old_method->is_old()) {
1247 continue; // skip uninteresting entries
1248 }
1249 assert(!old_method->is_deleted(), "itable methods may not be deleted");
1250
1251 Method* new_method = holder->method_with_idnum(old_method->orig_method_idnum());
1252
1253 assert(new_method != NULL, "method_with_idnum() should not be NULL");
1254 assert(old_method != new_method, "sanity check");
1255
1256 ime->initialize(new_method);
1257
1258 if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
1259 if (!(*trace_name_printed)) {
1260 // RC_TRACE_MESG macro has an embedded ResourceMark
1261 RC_TRACE_MESG(("adjust: name=%s",
1262 old_method->method_holder()->external_name()));
1263 *trace_name_printed = true;
1264 }
1265 // RC_TRACE macro has an embedded ResourceMark
1266 RC_TRACE(0x00200000, ("itable method update: %s(%s)",
1267 new_method->name()->as_C_string(),
1268 new_method->signature()->as_C_string()));
1269 }
1270 }
1271 }
1272
1273 // an itable should never contain old or obsolete methods
1274 bool klassItable::check_no_old_or_obsolete_entries() {
1275 itableMethodEntry* ime = method_entry(0);
1276 for (int i = 0; i < _size_method_table; i++) {
1277 Method* m = ime->method();
1278 if (m != NULL &&
1279 (NOT_PRODUCT(!m->is_valid() ||) m->is_old() || m->is_obsolete())) {
1280 return false;
1281 }
1282 ime++;
1283 }
1284 return true;
1285 }
1286
1287 void klassItable::dump_itable() {
1288 itableMethodEntry* ime = method_entry(0);
1289 tty->print_cr("itable dump --");
1290 for (int i = 0; i < _size_method_table; i++) {
1291 Method* m = ime->method();
1292 if (m != NULL) {
1293 tty->print(" (%5d) ", i);
1294 m->access_flags().print_on(tty);
1295 if (m->is_default_method()) {
1296 tty->print("default ");
1297 }
1298 tty->print(" -- ");
1299 m->print_name(tty);
1300 tty->cr();
1301 }
1302 ime++;
1303 }
1304 }
1305 #endif // INCLUDE_JVMTI
1306
1307
1308 // Setup
1309 class InterfaceVisiterClosure : public StackObj {
1310 public:
1311 virtual void doit(Klass* intf, int method_count) = 0;
1312 };
1313
1314 // Visit all interfaces with at least one itable method
1315 void visit_all_interfaces(Array<Klass*>* transitive_intf, InterfaceVisiterClosure *blk) {
1316 // Handle array argument
1317 for(int i = 0; i < transitive_intf->length(); i++) {
1318 Klass* intf = transitive_intf->at(i);
1319 assert(intf->is_interface(), "sanity check");
1320
1321 // Find no. of itable methods
1322 int method_count = 0;
1323 // method_count = klassItable::method_count_for_interface(intf);
1324 Array<Method*>* methods = InstanceKlass::cast(intf)->methods();
1325 if (methods->length() > 0) {
1326 for (int i = methods->length(); --i >= 0; ) {
1327 if (interface_method_needs_itable_index(methods->at(i))) {
1328 method_count++;
1329 }
1330 }
1331 }
1332
1333 // Only count interfaces with at least one method
1334 if (method_count > 0) {
1335 blk->doit(intf, method_count);
1336 }
1337 }
1338 }
1339
1340 class CountInterfacesClosure : public InterfaceVisiterClosure {
1341 private:
1342 int _nof_methods;
1343 int _nof_interfaces;
1344 public:
1345 CountInterfacesClosure() { _nof_methods = 0; _nof_interfaces = 0; }
1346
1347 int nof_methods() const { return _nof_methods; }
1348 int nof_interfaces() const { return _nof_interfaces; }
1349
1350 void doit(Klass* intf, int method_count) { _nof_methods += method_count; _nof_interfaces++; }
1351 };
1352
1353 class SetupItableClosure : public InterfaceVisiterClosure {
1354 private:
1355 itableOffsetEntry* _offset_entry;
1356 itableMethodEntry* _method_entry;
1357 address _klass_begin;
1358 public:
1359 SetupItableClosure(address klass_begin, itableOffsetEntry* offset_entry, itableMethodEntry* method_entry) {
1360 _klass_begin = klass_begin;
1361 _offset_entry = offset_entry;
1362 _method_entry = method_entry;
1363 }
1364
1365 itableMethodEntry* method_entry() const { return _method_entry; }
1366
1367 void doit(Klass* intf, int method_count) {
1368 int offset = ((address)_method_entry) - _klass_begin;
1369 _offset_entry->initialize(intf, offset);
1370 _offset_entry++;
1371 _method_entry += method_count;
1372 }
1373 };
1374
1375 int klassItable::compute_itable_size(Array<Klass*>* transitive_interfaces) {
1376 // Count no of interfaces and total number of interface methods
1377 CountInterfacesClosure cic;
1378 visit_all_interfaces(transitive_interfaces, &cic);
1379
1380 // There's alway an extra itable entry so we can null-terminate it.
1381 int itable_size = calc_itable_size(cic.nof_interfaces() + 1, cic.nof_methods());
1382
1383 // Statistics
1384 update_stats(itable_size * HeapWordSize);
1385
1386 return itable_size;
1387 }
1388
1389
1390 // Fill out offset table and interface klasses into the itable space
1391 void klassItable::setup_itable_offset_table(instanceKlassHandle klass) {
1392 if (klass->itable_length() == 0) return;
1393 assert(!klass->is_interface(), "Should have zero length itable");
1394
1395 // Count no of interfaces and total number of interface methods
1396 CountInterfacesClosure cic;
1397 visit_all_interfaces(klass->transitive_interfaces(), &cic);
1398 int nof_methods = cic.nof_methods();
1399 int nof_interfaces = cic.nof_interfaces();
1400
1401 // Add one extra entry so we can null-terminate the table
1402 nof_interfaces++;
1403
1404 assert(compute_itable_size(klass->transitive_interfaces()) ==
1405 calc_itable_size(nof_interfaces, nof_methods),
1406 "mismatch calculation of itable size");
1407
1408 // Fill-out offset table
1409 itableOffsetEntry* ioe = (itableOffsetEntry*)klass->start_of_itable();
1410 itableMethodEntry* ime = (itableMethodEntry*)(ioe + nof_interfaces);
1411 intptr_t* end = klass->end_of_itable();
1412 assert((oop*)(ime + nof_methods) <= (oop*)klass->start_of_nonstatic_oop_maps(), "wrong offset calculation (1)");
1413 assert((oop*)(end) == (oop*)(ime + nof_methods), "wrong offset calculation (2)");
1414
1415 // Visit all interfaces and initialize itable offset table
1416 SetupItableClosure sic((address)klass(), ioe, ime);
1417 visit_all_interfaces(klass->transitive_interfaces(), &sic);
1418
1419 #ifdef ASSERT
1420 ime = sic.method_entry();
1421 oop* v = (oop*) klass->end_of_itable();
1422 assert( (oop*)(ime) == v, "wrong offset calculation (2)");
1423 #endif
1424 }
1425
1426
1427 // inverse to itable_index
1428 Method* klassItable::method_for_itable_index(Klass* intf, int itable_index) {
1429 assert(InstanceKlass::cast(intf)->is_interface(), "sanity check");
1430 assert(intf->verify_itable_index(itable_index), "");
1431 Array<Method*>* methods = InstanceKlass::cast(intf)->methods();
1432
1433 if (itable_index < 0 || itable_index >= method_count_for_interface(intf))
1434 return NULL; // help caller defend against bad indices
1435
1436 int index = itable_index;
1437 Method* m = methods->at(index);
1438 int index2 = -1;
1439 while (!m->has_itable_index() ||
1440 (index2 = m->itable_index()) != itable_index) {
1441 assert(index2 < itable_index, "monotonic");
1442 if (++index == methods->length())
1443 return NULL;
1444 m = methods->at(index);
1445 }
1446 assert(m->itable_index() == itable_index, "correct inverse");
1447
1448 return m;
1449 }
1450
1451 void klassVtable::verify(outputStream* st, bool forced) {
1452 // make sure table is initialized
1453 if (!Universe::is_fully_initialized()) return;
1454 #ifndef PRODUCT
1455 // avoid redundant verifies
1456 if (!forced && _verify_count == Universe::verify_count()) return;
1457 _verify_count = Universe::verify_count();
1458 #endif
1459 oop* end_of_obj = (oop*)_klass() + _klass()->size();
1460 oop* end_of_vtable = (oop *)&table()[_length];
1461 if (end_of_vtable > end_of_obj) {
1462 fatal("klass %s: klass object too short (vtable extends beyond end)",
1463 _klass->internal_name());
1464 }
1465
1466 for (int i = 0; i < _length; i++) table()[i].verify(this, st);
1467 // verify consistency with superKlass vtable
1468 Klass* super = _klass->super();
1469 if (super != NULL) {
1470 InstanceKlass* sk = InstanceKlass::cast(super);
1471 klassVtable* vt = sk->vtable();
1472 for (int i = 0; i < vt->length(); i++) {
1473 verify_against(st, vt, i);
1474 }
1475 }
1476 }
1477
1478 void klassVtable::verify_against(outputStream* st, klassVtable* vt, int index) {
1479 vtableEntry* vte = &vt->table()[index];
1480 if (vte->method()->name() != table()[index].method()->name() ||
1481 vte->method()->signature() != table()[index].method()->signature()) {
1482 fatal("mismatched name/signature of vtable entries");
1483 }
1484 }
1485
1486 #ifndef PRODUCT
1487 void klassVtable::print() {
1488 ResourceMark rm;
1489 tty->print("klassVtable for klass %s (length %d):\n", _klass->internal_name(), length());
1490 for (int i = 0; i < length(); i++) {
1491 table()[i].print();
1492 tty->cr();
1493 }
1494 }
1495 #endif
1496
1497 void vtableEntry::verify(klassVtable* vt, outputStream* st) {
1498 NOT_PRODUCT(FlagSetting fs(IgnoreLockingAssertions, true));
1499 assert(method() != NULL, "must have set method");
1500 method()->verify();
1501 // we sub_type, because it could be a miranda method
1502 if (!vt->klass()->is_subtype_of(method()->method_holder())) {
1503 #ifndef PRODUCT
1504 print();
1505 #endif
1506 fatal("vtableEntry " PTR_FORMAT ": method is from subclass", p2i(this));
1507 }
1508 }
1509
1510 #ifndef PRODUCT
1511
1512 void vtableEntry::print() {
1513 ResourceMark rm;
1514 tty->print("vtableEntry %s: ", method()->name()->as_C_string());
1515 if (Verbose) {
1516 tty->print("m " INTPTR_FORMAT_W(#) " ", p2i(method()));
1517 }
1518 }
1519
1520 class VtableStats : AllStatic {
1521 public:
1522 static int no_klasses; // # classes with vtables
1523 static int no_array_klasses; // # array classes
1524 static int no_instance_klasses; // # instanceKlasses
1525 static int sum_of_vtable_len; // total # of vtable entries
1526 static int sum_of_array_vtable_len; // total # of vtable entries in array klasses only
1527 static int fixed; // total fixed overhead in bytes
1528 static int filler; // overhead caused by filler bytes
1529 static int entries; // total bytes consumed by vtable entries
1530 static int array_entries; // total bytes consumed by array vtable entries
1531
1532 static void do_class(Klass* k) {
1533 Klass* kl = k;
1534 klassVtable* vt = kl->vtable();
1535 if (vt == NULL) return;
1536 no_klasses++;
1537 if (kl->oop_is_instance()) {
1538 no_instance_klasses++;
1539 kl->array_klasses_do(do_class);
1540 }
1541 if (kl->oop_is_array()) {
1542 no_array_klasses++;
1543 sum_of_array_vtable_len += vt->length();
1544 }
1545 sum_of_vtable_len += vt->length();
1546 }
1547
1548 static void compute() {
1549 SystemDictionary::classes_do(do_class);
1550 fixed = no_klasses * oopSize; // vtable length
1551 // filler size is a conservative approximation
1552 filler = oopSize * (no_klasses - no_instance_klasses) * (sizeof(InstanceKlass) - sizeof(ArrayKlass) - 1);
1553 entries = sizeof(vtableEntry) * sum_of_vtable_len;
1554 array_entries = sizeof(vtableEntry) * sum_of_array_vtable_len;
1555 }
1556 };
1557
1558 int VtableStats::no_klasses = 0;
1559 int VtableStats::no_array_klasses = 0;
1560 int VtableStats::no_instance_klasses = 0;
1561 int VtableStats::sum_of_vtable_len = 0;
1562 int VtableStats::sum_of_array_vtable_len = 0;
1563 int VtableStats::fixed = 0;
1564 int VtableStats::filler = 0;
1565 int VtableStats::entries = 0;
1566 int VtableStats::array_entries = 0;
1567
1568 void klassVtable::print_statistics() {
1569 ResourceMark rm;
1570 HandleMark hm;
1571 VtableStats::compute();
1572 tty->print_cr("vtable statistics:");
1573 tty->print_cr("%6d classes (%d instance, %d array)", VtableStats::no_klasses, VtableStats::no_instance_klasses, VtableStats::no_array_klasses);
1574 int total = VtableStats::fixed + VtableStats::filler + VtableStats::entries;
1575 tty->print_cr("%6d bytes fixed overhead (refs + vtable object header)", VtableStats::fixed);
1576 tty->print_cr("%6d bytes filler overhead", VtableStats::filler);
1577 tty->print_cr("%6d bytes for vtable entries (%d for arrays)", VtableStats::entries, VtableStats::array_entries);
1578 tty->print_cr("%6d bytes total", total);
1579 }
1580
1581 int klassItable::_total_classes; // Total no. of classes with itables
1582 long klassItable::_total_size; // Total no. of bytes used for itables
1583
1584 void klassItable::print_statistics() {
1585 tty->print_cr("itable statistics:");
1586 tty->print_cr("%6d classes with itables", _total_classes);
1587 tty->print_cr("%6ld K uses for itables (average by class: %ld bytes)", _total_size / K, _total_size / _total_classes);
1588 }
1589
1590 #endif // PRODUCT