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 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
42
43 inline InstanceKlass* klassVtable::ik() const {
44 Klass* k = _klass();
45 assert(k->oop_is_instance(), "not an InstanceKlass");
46 return (InstanceKlass*)k;
47 }
48
49
50 // this function computes the vtable size (including the size needed for miranda
51 // methods) and the number of miranda methods in this class.
52 // Note on Miranda methods: Let's say there is a class C that implements
53 // interface I, and none of C's superclasses implements I.
54 // Let's say there is an abstract method m in I that neither C
55 // nor any of its super classes implement (i.e there is no method of any access,
56 // with the same name and signature as m), then m is a Miranda method which is
57 // entered as a public abstract method in C's vtable. From then on it should
58 // treated as any other public method in C for method over-ride purposes.
59 void klassVtable::compute_vtable_size_and_num_mirandas(
60 int* vtable_length_ret, int* num_new_mirandas,
61 GrowableArray<Method*>* all_mirandas, Klass* super,
62 Array<Method*>* methods, AccessFlags class_flags,
63 Handle classloader, Symbol* classname, Array<Klass*>* local_interfaces,
64 TRAPS) {
65 No_Safepoint_Verifier nsv;
66
67 // set up default result values
68 int vtable_length = 0;
69
70 // start off with super's vtable length
71 InstanceKlass* sk = (InstanceKlass*)super;
72 vtable_length = super == NULL ? 0 : sk->vtable_length();
73
74 // go thru each method in the methods table to see if it needs a new entry
75 int len = methods->length();
76 for (int i = 0; i < len; i++) {
77 assert(methods->at(i)->is_method(), "must be a Method*");
78 methodHandle mh(THREAD, methods->at(i));
79
80 if (needs_new_vtable_entry(mh, super, classloader, classname, class_flags, THREAD)) {
81 vtable_length += vtableEntry::size(); // we need a new entry
82 }
83 }
84
85 GrowableArray<Method*> new_mirandas(20);
86 // compute the number of mirandas methods that must be added to the end
87 get_mirandas(&new_mirandas, all_mirandas, super, methods, NULL, local_interfaces);
88 *num_new_mirandas = new_mirandas.length();
89
90 // Interfaces do not need interface methods in their vtables
91 // This includes miranda methods and during later processing, default methods
92 if (!class_flags.is_interface()) {
93 vtable_length += *num_new_mirandas * vtableEntry::size();
94 }
95
96 if (Universe::is_bootstrapping() && vtable_length == 0) {
97 // array classes don't have their superclass set correctly during
98 // bootstrapping
99 vtable_length = Universe::base_vtable_size();
100 }
101
102 if (super == NULL && vtable_length != Universe::base_vtable_size()) {
103 if (Universe::is_bootstrapping()) {
104 // Someone is attempting to override java.lang.Object incorrectly on the
105 // bootclasspath. The JVM cannot recover from this error including throwing
106 // an exception
107 vm_exit_during_initialization("Incompatible definition of java.lang.Object");
108 } else {
109 // Someone is attempting to redefine java.lang.Object incorrectly. The
110 // only way this should happen is from
111 // SystemDictionary::resolve_from_stream(), which will detect this later
112 // and throw a security exception. So don't assert here to let
113 // the exception occur.
114 vtable_length = Universe::base_vtable_size();
115 }
116 }
117 assert(vtable_length % vtableEntry::size() == 0, "bad vtable length");
118 assert(vtable_length >= Universe::base_vtable_size(), "vtable too small");
119
120 *vtable_length_ret = vtable_length;
121 }
122
123 int klassVtable::index_of(Method* m, int len) const {
124 assert(m->has_vtable_index(), "do not ask this of non-vtable methods");
125 return m->vtable_index();
126 }
127
128 // Copy super class's vtable to the first part (prefix) of this class's vtable,
129 // and return the number of entries copied. Expects that 'super' is the Java
130 // super class (arrays can have "array" super classes that must be skipped).
131 int klassVtable::initialize_from_super(KlassHandle super) {
132 if (super.is_null()) {
133 return 0;
134 } else {
135 // copy methods from superKlass
136 // can't inherit from array class, so must be InstanceKlass
137 assert(super->oop_is_instance(), "must be instance klass");
138 InstanceKlass* sk = (InstanceKlass*)super();
139 klassVtable* superVtable = sk->vtable();
140 assert(superVtable->length() <= _length, "vtable too short");
141 #ifdef ASSERT
142 superVtable->verify(tty, true);
143 #endif
144 superVtable->copy_vtable_to(table());
145 #ifndef PRODUCT
146 if (PrintVtables && Verbose) {
147 ResourceMark rm;
148 tty->print_cr("copy vtable from %s to %s size %d", sk->internal_name(), klass()->internal_name(), _length);
149 }
150 #endif
151 return superVtable->length();
152 }
153 }
154
155 //
156 // Revised lookup semantics introduced 1.3 (Kestrel beta)
157 void klassVtable::initialize_vtable(bool checkconstraints, TRAPS) {
158
159 // Note: Arrays can have intermediate array supers. Use java_super to skip them.
160 KlassHandle super (THREAD, klass()->java_super());
161 int nofNewEntries = 0;
162
163 if (PrintVtables && !klass()->oop_is_array()) {
164 ResourceMark rm(THREAD);
165 tty->print_cr("Initializing: %s", _klass->name()->as_C_string());
166 }
167
168 #ifdef ASSERT
169 oop* end_of_obj = (oop*)_klass() + _klass()->size();
170 oop* end_of_vtable = (oop*)&table()[_length];
171 assert(end_of_vtable <= end_of_obj, "vtable extends beyond end");
172 #endif
173
174 if (Universe::is_bootstrapping()) {
175 // just clear everything
176 for (int i = 0; i < _length; i++) table()[i].clear();
177 return;
178 }
179
180 int super_vtable_len = initialize_from_super(super);
181 if (klass()->oop_is_array()) {
182 assert(super_vtable_len == _length, "arrays shouldn't introduce new methods");
183 } else {
184 assert(_klass->oop_is_instance(), "must be InstanceKlass");
185
186 Array<Method*>* methods = ik()->methods();
187 int len = methods->length();
188 int initialized = super_vtable_len;
189
190 // Check each of this class's methods against super;
191 // if override, replace in copy of super vtable, otherwise append to end
192 for (int i = 0; i < len; i++) {
193 // update_inherited_vtable can stop for gc - ensure using handles
194 HandleMark hm(THREAD);
195 assert(methods->at(i)->is_method(), "must be a Method*");
196 methodHandle mh(THREAD, methods->at(i));
197
198 bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, -1, checkconstraints, CHECK);
199
200 if (needs_new_entry) {
201 put_method_at(mh(), initialized);
202 mh()->set_vtable_index(initialized); // set primary vtable index
203 initialized++;
204 }
205 }
206
207 // update vtable with default_methods
208 Array<Method*>* default_methods = ik()->default_methods();
209 if (default_methods != NULL) {
210 len = default_methods->length();
211 if (len > 0) {
212 Array<int>* def_vtable_indices = NULL;
213 if ((def_vtable_indices = ik()->default_vtable_indices()) == NULL) {
214 def_vtable_indices = ik()->create_new_default_vtable_indices(len, CHECK);
215 } else {
216 assert(def_vtable_indices->length() == len, "reinit vtable len?");
217 }
218 for (int i = 0; i < len; i++) {
219 HandleMark hm(THREAD);
220 assert(default_methods->at(i)->is_method(), "must be a Method*");
221 methodHandle mh(THREAD, default_methods->at(i));
222
223 bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, i, checkconstraints, CHECK);
224
225 // needs new entry
226 if (needs_new_entry) {
227 put_method_at(mh(), initialized);
228 def_vtable_indices->at_put(i, initialized); //set vtable index
229 initialized++;
230 }
231 }
232 }
233 }
234
235 // add miranda methods; it will also return the updated initialized
236 // Interfaces do not need interface methods in their vtables
237 // This includes miranda methods and during later processing, default methods
238 if (!ik()->is_interface()) {
239 initialized = fill_in_mirandas(initialized);
240 }
241
242 // In class hierarchies where the accessibility is not increasing (i.e., going from private ->
243 // package_private -> public/protected), the vtable might actually be smaller than our initial
244 // calculation.
245 assert(initialized <= _length, "vtable initialization failed");
246 for(;initialized < _length; initialized++) {
247 put_method_at(NULL, initialized);
248 }
249 NOT_PRODUCT(verify(tty, true));
250 }
251 }
252
253 // Called for cases where a method does not override its superclass' vtable entry
254 // For bytecodes not produced by javac together it is possible that a method does not override
255 // the superclass's method, but might indirectly override a super-super class's vtable entry
256 // If none found, return a null superk, else return the superk of the method this does override
257 // For public and protected methods: if they override a superclass, they will
258 // also be overridden themselves appropriately.
259 // Private methods do not override and are not overridden.
260 // Package Private methods are trickier:
261 // e.g. P1.A, pub m
262 // P2.B extends A, package private m
263 // P1.C extends B, public m
264 // P1.C.m needs to override P1.A.m and can not override P2.B.m
265 // Therefore: all package private methods need their own vtable entries for
266 // them to be the root of an inheritance overriding decision
267 // Package private methods may also override other vtable entries
268 InstanceKlass* klassVtable::find_transitive_override(InstanceKlass* initialsuper, methodHandle target_method,
269 int vtable_index, Handle target_loader, Symbol* target_classname, Thread * THREAD) {
270 InstanceKlass* superk = initialsuper;
271 while (superk != NULL && superk->super() != NULL) {
272 InstanceKlass* supersuperklass = InstanceKlass::cast(superk->super());
273 klassVtable* ssVtable = supersuperklass->vtable();
274 if (vtable_index < ssVtable->length()) {
275 Method* super_method = ssVtable->method_at(vtable_index);
276 #ifndef PRODUCT
277 Symbol* name= target_method()->name();
278 Symbol* signature = target_method()->signature();
279 assert(super_method->name() == name && super_method->signature() == signature, "vtable entry name/sig mismatch");
280 #endif
281 if (supersuperklass->is_override(super_method, target_loader, target_classname, THREAD)) {
282 #ifndef PRODUCT
283 if (PrintVtables && Verbose) {
284 ResourceMark rm(THREAD);
285 char* sig = target_method()->name_and_sig_as_C_string();
286 tty->print("transitive overriding superclass %s with %s::%s index %d, original flags: ",
287 supersuperklass->internal_name(),
288 _klass->internal_name(), sig, vtable_index);
289 super_method->access_flags().print_on(tty);
290 if (super_method->is_default_method()) {
291 tty->print("default ");
292 }
293 tty->print("overriders flags: ");
294 target_method->access_flags().print_on(tty);
295 if (target_method->is_default_method()) {
296 tty->print("default ");
297 }
298 }
299 #endif /*PRODUCT*/
300 break; // return found superk
301 }
302 } else {
303 // super class has no vtable entry here, stop transitive search
304 superk = (InstanceKlass*)NULL;
305 break;
306 }
307 // if no override found yet, continue to search up
308 superk = InstanceKlass::cast(superk->super());
309 }
310
311 return superk;
312 }
313
314 // Update child's copy of super vtable for overrides
315 // OR return true if a new vtable entry is required.
316 // Only called for InstanceKlass's, i.e. not for arrays
317 // If that changed, could not use _klass as handle for klass
318 bool klassVtable::update_inherited_vtable(InstanceKlass* klass, methodHandle target_method,
319 int super_vtable_len, int default_index,
320 bool checkconstraints, TRAPS) {
321 ResourceMark rm;
322 bool allocate_new = true;
323 assert(klass->oop_is_instance(), "must be InstanceKlass");
324
325 Array<int>* def_vtable_indices = NULL;
326 bool is_default = false;
327 // default methods are concrete methods in superinterfaces which are added to the vtable
328 // with their real method_holder
329 // Since vtable and itable indices share the same storage, don't touch
330 // the default method's real vtable/itable index
331 // default_vtable_indices stores the vtable value relative to this inheritor
332 if (default_index >= 0 ) {
333 is_default = true;
334 def_vtable_indices = klass->default_vtable_indices();
335 assert(def_vtable_indices != NULL, "def vtable alloc?");
336 assert(default_index <= def_vtable_indices->length(), "def vtable len?");
337 } else {
338 assert(klass == target_method()->method_holder(), "caller resp.");
339 // Initialize the method's vtable index to "nonvirtual".
340 // If we allocate a vtable entry, we will update it to a non-negative number.
341 target_method()->set_vtable_index(Method::nonvirtual_vtable_index);
342 }
343
344 // Static and <init> methods are never in
345 if (target_method()->is_static() || target_method()->name() == vmSymbols::object_initializer_name()) {
346 return false;
347 }
348
349 if (target_method->is_final_method(klass->access_flags())) {
350 // a final method never needs a new entry; final methods can be statically
351 // resolved and they have to be present in the vtable only if they override
352 // a super's method, in which case they re-use its entry
353 allocate_new = false;
354 } else if (klass->is_interface()) {
355 allocate_new = false; // see note below in needs_new_vtable_entry
356 // An interface never allocates new vtable slots, only inherits old ones.
357 // This method will either be assigned its own itable index later,
358 // or be assigned an inherited vtable index in the loop below.
359 // default methods inherited by classes store their vtable indices
360 // in the inheritor's default_vtable_indices
361 // default methods inherited by interfaces may already have a
362 // valid itable index, if so, don't change it
363 // overpass methods in an interface will be assigned an itable index later
364 // by an inheriting class
365 if (!is_default || !target_method()->has_itable_index()) {
366 target_method()->set_vtable_index(Method::pending_itable_index);
367 }
368 }
369
370 // we need a new entry if there is no superclass
371 if (klass->super() == NULL) {
372 return allocate_new;
373 }
374
375 // private methods in classes always have a new entry in the vtable
376 // specification interpretation since classic has
377 // private methods not overriding
378 // JDK8 adds private methods in interfaces which require invokespecial
379 if (target_method()->is_private()) {
380 return allocate_new;
381 }
382
383 // search through the vtable and update overridden entries
384 // Since check_signature_loaders acquires SystemDictionary_lock
385 // which can block for gc, once we are in this loop, use handles
386 // For classfiles built with >= jdk7, we now look for transitive overrides
387
388 Symbol* name = target_method()->name();
389 Symbol* signature = target_method()->signature();
390
391 KlassHandle target_klass(THREAD, target_method()->method_holder());
392 if (target_klass == NULL) {
393 target_klass = _klass;
394 }
395
396 Handle target_loader(THREAD, target_klass->class_loader());
397
398 Symbol* target_classname = target_klass->name();
399 for(int i = 0; i < super_vtable_len; i++) {
400 Method* super_method = method_at(i);
401 // Check if method name matches
402 if (super_method->name() == name && super_method->signature() == signature) {
403
404 // get super_klass for method_holder for the found method
405 InstanceKlass* super_klass = super_method->method_holder();
406
407 // private methods are also never overridden
408 if (!super_method->is_private() &&
409 (is_default
410 || ((super_klass->is_override(super_method, target_loader, target_classname, THREAD))
411 || ((klass->major_version() >= VTABLE_TRANSITIVE_OVERRIDE_VERSION)
412 && ((super_klass = find_transitive_override(super_klass,
413 target_method, i, target_loader,
414 target_classname, THREAD))
415 != (InstanceKlass*)NULL)))))
416 {
417 // Package private methods always need a new entry to root their own
418 // overriding. They may also override other methods.
419 if (!target_method()->is_package_private()) {
420 allocate_new = false;
421 }
422
423 if (checkconstraints) {
424 // Override vtable entry if passes loader constraint check
425 // if loader constraint checking requested
426 // No need to visit his super, since he and his super
427 // have already made any needed loader constraints.
428 // Since loader constraints are transitive, it is enough
429 // to link to the first super, and we get all the others.
430 Handle super_loader(THREAD, super_klass->class_loader());
431
432 if (target_loader() != super_loader()) {
433 ResourceMark rm(THREAD);
434 Symbol* failed_type_symbol =
435 SystemDictionary::check_signature_loaders(signature, target_loader,
436 super_loader, true,
437 CHECK_(false));
438 if (failed_type_symbol != NULL) {
439 const char* msg = "loader constraint violation: when resolving "
440 "overridden method \"%s\" the class loader (instance"
441 " of %s) of the current class, %s, and its superclass loader "
442 "(instance of %s), have different Class objects for the type "
443 "%s used in the signature";
444 char* sig = target_method()->name_and_sig_as_C_string();
445 const char* loader1 = SystemDictionary::loader_name(target_loader());
446 char* current = target_klass->name()->as_C_string();
447 const char* loader2 = SystemDictionary::loader_name(super_loader());
448 char* failed_type_name = failed_type_symbol->as_C_string();
449 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
450 strlen(current) + strlen(loader2) + strlen(failed_type_name);
451 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
452 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2,
453 failed_type_name);
454 THROW_MSG_(vmSymbols::java_lang_LinkageError(), buf, false);
455 }
456 }
457 }
458
459 put_method_at(target_method(), i);
460 if (!is_default) {
461 target_method()->set_vtable_index(i);
462 } else {
463 if (def_vtable_indices != NULL) {
464 def_vtable_indices->at_put(default_index, i);
465 }
466 assert(super_method->is_default_method() || super_method->is_overpass()
467 || super_method->is_abstract(), "default override error");
468 }
469
470
471 #ifndef PRODUCT
472 if (PrintVtables && Verbose) {
473 ResourceMark rm(THREAD);
474 char* sig = target_method()->name_and_sig_as_C_string();
475 tty->print("overriding with %s::%s index %d, original flags: ",
476 target_klass->internal_name(), sig, i);
477 super_method->access_flags().print_on(tty);
478 if (super_method->is_default_method()) {
479 tty->print("default ");
480 }
481 if (super_method->is_overpass()) {
482 tty->print("overpass");
483 }
484 tty->print("overriders flags: ");
485 target_method->access_flags().print_on(tty);
486 if (target_method->is_default_method()) {
487 tty->print("default ");
488 }
489 if (target_method->is_overpass()) {
490 tty->print("overpass");
491 }
492 tty->cr();
493 }
494 #endif /*PRODUCT*/
495 } else {
496 // allocate_new = true; default. We might override one entry,
497 // but not override another. Once we override one, not need new
498 #ifndef PRODUCT
499 if (PrintVtables && Verbose) {
500 ResourceMark rm(THREAD);
501 char* sig = target_method()->name_and_sig_as_C_string();
502 tty->print("NOT overriding with %s::%s index %d, original flags: ",
503 target_klass->internal_name(), sig,i);
504 super_method->access_flags().print_on(tty);
505 if (super_method->is_default_method()) {
506 tty->print("default ");
507 }
508 if (super_method->is_overpass()) {
509 tty->print("overpass");
510 }
511 tty->print("overriders flags: ");
512 target_method->access_flags().print_on(tty);
513 if (target_method->is_default_method()) {
514 tty->print("default ");
515 }
516 if (target_method->is_overpass()) {
517 tty->print("overpass");
518 }
519 tty->cr();
520 }
521 #endif /*PRODUCT*/
522 }
523 }
524 }
525 return allocate_new;
526 }
527
528 void klassVtable::put_method_at(Method* m, int index) {
529 #ifndef PRODUCT
530 if (PrintVtables && Verbose) {
531 ResourceMark rm;
532 const char* sig = (m != NULL) ? m->name_and_sig_as_C_string() : "<NULL>";
533 tty->print("adding %s at index %d, flags: ", sig, index);
534 if (m != NULL) {
535 m->access_flags().print_on(tty);
536 if (m->is_default_method()) {
537 tty->print("default ");
538 }
539 if (m->is_overpass()) {
540 tty->print("overpass");
541 }
542 }
543 tty->cr();
544 }
545 #endif
546 table()[index].set(m);
547 }
548
549 // Find out if a method "m" with superclass "super", loader "classloader" and
550 // name "classname" needs a new vtable entry. Let P be a class package defined
551 // by "classloader" and "classname".
552 // NOTE: The logic used here is very similar to the one used for computing
553 // the vtables indices for a method. We cannot directly use that function because,
554 // we allocate the InstanceKlass at load time, and that requires that the
555 // superclass has been loaded.
556 // However, the vtable entries are filled in at link time, and therefore
557 // the superclass' vtable may not yet have been filled in.
558 bool klassVtable::needs_new_vtable_entry(methodHandle target_method,
559 Klass* super,
560 Handle classloader,
561 Symbol* classname,
562 AccessFlags class_flags,
563 TRAPS) {
564 if (class_flags.is_interface()) {
565 // Interfaces do not use vtables, except for java.lang.Object methods,
566 // so there is no point to assigning
567 // a vtable index to any of their local methods. If we refrain from doing this,
568 // we can use Method::_vtable_index to hold the itable index
569 return false;
570 }
571
572 if (target_method->is_final_method(class_flags) ||
573 // a final method never needs a new entry; final methods can be statically
574 // resolved and they have to be present in the vtable only if they override
575 // a super's method, in which case they re-use its entry
576 (target_method()->is_static()) ||
577 // static methods don't need to be in vtable
578 (target_method()->name() == vmSymbols::object_initializer_name())
579 // <init> is never called dynamically-bound
580 ) {
581 return false;
582 }
583
584 // Concrete interface methods do not need new entries, they override
585 // abstract method entries using default inheritance rules
586 if (target_method()->method_holder() != NULL &&
587 target_method()->method_holder()->is_interface() &&
588 !target_method()->is_abstract() ) {
589 return false;
590 }
591
592 // we need a new entry if there is no superclass
593 if (super == NULL) {
594 return true;
595 }
596
597 // private methods in classes always have a new entry in the vtable
598 // specification interpretation since classic has
599 // private methods not overriding
600 // JDK8 adds private methods in interfaces which require invokespecial
601 if (target_method()->is_private()) {
602 return true;
603 }
604
605 // Package private methods always need a new entry to root their own
606 // overriding. This allows transitive overriding to work.
607 if (target_method()->is_package_private()) {
608 return true;
609 }
610
611 // search through the super class hierarchy to see if we need
612 // a new entry
613 ResourceMark rm;
614 Symbol* name = target_method()->name();
615 Symbol* signature = target_method()->signature();
616 Klass* k = super;
617 Method* super_method = NULL;
618 InstanceKlass *holder = NULL;
619 Method* recheck_method = NULL;
620 while (k != NULL) {
621 // lookup through the hierarchy for a method with matching name and sign.
622 super_method = InstanceKlass::cast(k)->lookup_method(name, signature);
623 if (super_method == NULL) {
624 break; // we still have to search for a matching miranda method
625 }
626 // get the class holding the matching method
627 // make sure you use that class for is_override
628 InstanceKlass* superk = super_method->method_holder();
629 // we want only instance method matches
630 // pretend private methods are not in the super vtable
631 // since we do override around them: e.g. a.m pub/b.m private/c.m pub,
632 // ignore private, c.m pub does override a.m pub
633 // For classes that were not javac'd together, we also do transitive overriding around
634 // methods that have less accessibility
635 if ((!super_method->is_static()) &&
636 (!super_method->is_private())) {
637 if (superk->is_override(super_method, classloader, classname, THREAD)) {
638 return false;
639 // else keep looking for transitive overrides
640 }
641 }
642
643 // Start with lookup result and continue to search up
644 k = superk->super(); // haven't found an override match yet; continue to look
645 }
646
647 // if the target method is public or protected it may have a matching
648 // miranda method in the super, whose entry it should re-use.
649 // Actually, to handle cases that javac would not generate, we need
650 // this check for all access permissions.
651 InstanceKlass *sk = InstanceKlass::cast(super);
652 if (sk->has_miranda_methods()) {
653 if (sk->lookup_method_in_all_interfaces(name, signature, Klass::find_defaults) != NULL) {
654 return false; // found a matching miranda; we do not need a new entry
655 }
656 }
657 return true; // found no match; we need a new entry
658 }
659
660 // Support for miranda methods
661
662 // get the vtable index of a miranda method with matching "name" and "signature"
663 int klassVtable::index_of_miranda(Symbol* name, Symbol* signature) {
664 // search from the bottom, might be faster
665 for (int i = (length() - 1); i >= 0; i--) {
666 Method* m = table()[i].method();
667 if (is_miranda_entry_at(i) &&
668 m->name() == name && m->signature() == signature) {
669 return i;
670 }
671 }
672 return Method::invalid_vtable_index;
673 }
674
675 // check if an entry at an index is miranda
676 // requires that method m at entry be declared ("held") by an interface.
677 bool klassVtable::is_miranda_entry_at(int i) {
678 Method* m = method_at(i);
679 Klass* method_holder = m->method_holder();
680 InstanceKlass *mhk = InstanceKlass::cast(method_holder);
681
682 // miranda methods are public abstract instance interface methods in a class's vtable
683 if (mhk->is_interface()) {
684 assert(m->is_public(), "should be public");
685 assert(ik()->implements_interface(method_holder) , "this class should implement the interface");
686 // the search could find a miranda or a default method
687 if (is_miranda(m, ik()->methods(), ik()->default_methods(), ik()->super())) {
688 return true;
689 }
690 }
691 return false;
692 }
693
694 // check if a method is a miranda method, given a class's methods table,
695 // its default_method table and its super
696 // Miranda methods are calculated twice:
697 // first: before vtable size calculation: including abstract and superinterface default
698 // We include potential default methods to give them space in the vtable.
699 // During the first run, the default_methods list is empty
700 // This is seen by default method creation
701 // Second: recalculated during vtable initialization: only include abstract methods.
702 // During the second run, default_methods is set up, so concrete methods from
703 // superinterfaces with matching names/signatures to default_methods are already
704 // in the default_methods list and do not need to be appended to the vtable
705 // as mirandas
706 // This is seen by link resolution and selection.
707 // "miranda" means not static, not defined by this class.
708 // private methods in interfaces do not belong in the miranda list.
709 // the caller must make sure that the method belongs to an interface implemented by the class
710 // Miranda methods only include public interface instance methods
711 // Not private methods, not static methods, not default == concrete abstract
712 // Miranda methods also do not include overpass methods in interfaces
713 bool klassVtable::is_miranda(Method* m, Array<Method*>* class_methods,
714 Array<Method*>* default_methods, Klass* super) {
715 if (m->is_static() || m->is_private() || m->is_overpass()) {
716 return false;
717 }
718 Symbol* name = m->name();
719 Symbol* signature = m->signature();
720 Method* mo;
721
722 if ((mo = InstanceKlass::find_instance_method(class_methods, name, signature)) == NULL) {
723 // did not find it in the method table of the current class
724 if ((default_methods == NULL) ||
725 InstanceKlass::find_method(default_methods, name, signature) == NULL) {
726 if (super == NULL) {
727 // super doesn't exist
728 return true;
729 }
730
731 mo = InstanceKlass::cast(super)->lookup_method(name, signature);
732 while (mo != NULL && mo->access_flags().is_static()
733 && mo->method_holder() != NULL
734 && mo->method_holder()->super() != NULL)
735 {
736 mo = mo->method_holder()->super()->uncached_lookup_method(name, signature, Klass::find_overpass);
737 }
738 if (mo == NULL || mo->access_flags().is_private() ) {
739 // super class hierarchy does not implement it or protection is different
740 return true;
741 }
742 }
743 } else {
744 // if the local class has a private method, the miranda will not
745 // override it, so a vtable slot is needed
746 if (mo->access_flags().is_private()) {
747
748 // Second round, weed out any superinterface methods that turned
749 // into default methods, i.e. were concrete not abstract in the end
750 if ((default_methods == NULL) ||
751 InstanceKlass::find_method(default_methods, name, signature) == NULL) {
752 return true;
753 }
754 }
755 }
756
757 return false;
758 }
759
760 // Scans current_interface_methods for miranda methods that do not
761 // already appear in new_mirandas, or default methods, and are also not defined-and-non-private
762 // in super (superclass). These mirandas are added to all_mirandas if it is
763 // not null; in addition, those that are not duplicates of miranda methods
764 // inherited by super from its interfaces are added to new_mirandas.
765 // Thus, new_mirandas will be the set of mirandas that this class introduces,
766 // all_mirandas will be the set of all mirandas applicable to this class
767 // including all defined in superclasses.
768 void klassVtable::add_new_mirandas_to_lists(
769 GrowableArray<Method*>* new_mirandas, GrowableArray<Method*>* all_mirandas,
770 Array<Method*>* current_interface_methods, Array<Method*>* class_methods,
771 Array<Method*>* default_methods, Klass* super) {
772
773 // iterate thru the current interface's method to see if it a miranda
774 int num_methods = current_interface_methods->length();
775 for (int i = 0; i < num_methods; i++) {
776 Method* im = current_interface_methods->at(i);
777 bool is_duplicate = false;
778 int num_of_current_mirandas = new_mirandas->length();
779 // check for duplicate mirandas in different interfaces we implement
780 for (int j = 0; j < num_of_current_mirandas; j++) {
781 Method* miranda = new_mirandas->at(j);
782 if ((im->name() == miranda->name()) &&
783 (im->signature() == miranda->signature())) {
784 is_duplicate = true;
785 break;
786 }
787 }
788
789 if (!is_duplicate) { // we don't want duplicate miranda entries in the vtable
790 if (is_miranda(im, class_methods, default_methods, super)) { // is it a miranda at all?
791 InstanceKlass *sk = InstanceKlass::cast(super);
792 // check if it is a duplicate of a super's miranda
793 if (sk->lookup_method_in_all_interfaces(im->name(), im->signature(), Klass::find_defaults) == NULL) {
794 new_mirandas->append(im);
795 }
796 if (all_mirandas != NULL) {
797 all_mirandas->append(im);
798 }
799 }
800 }
801 }
802 }
803
804 void klassVtable::get_mirandas(GrowableArray<Method*>* new_mirandas,
805 GrowableArray<Method*>* all_mirandas,
806 Klass* super, Array<Method*>* class_methods,
807 Array<Method*>* default_methods,
808 Array<Klass*>* local_interfaces) {
809 assert((new_mirandas->length() == 0) , "current mirandas must be 0");
810
811 // iterate thru the local interfaces looking for a miranda
812 int num_local_ifs = local_interfaces->length();
813 for (int i = 0; i < num_local_ifs; i++) {
814 InstanceKlass *ik = InstanceKlass::cast(local_interfaces->at(i));
815 add_new_mirandas_to_lists(new_mirandas, all_mirandas,
816 ik->methods(), class_methods,
817 default_methods, super);
818 // iterate thru each local's super interfaces
819 Array<Klass*>* super_ifs = ik->transitive_interfaces();
820 int num_super_ifs = super_ifs->length();
821 for (int j = 0; j < num_super_ifs; j++) {
822 InstanceKlass *sik = InstanceKlass::cast(super_ifs->at(j));
823 add_new_mirandas_to_lists(new_mirandas, all_mirandas,
824 sik->methods(), class_methods,
825 default_methods, super);
826 }
827 }
828 }
829
830 // Discover miranda methods ("miranda" = "interface abstract, no binding"),
831 // and append them into the vtable starting at index initialized,
832 // return the new value of initialized.
833 // Miranda methods use vtable entries, but do not get assigned a vtable_index
834 // The vtable_index is discovered by searching from the end of the vtable
835 int klassVtable::fill_in_mirandas(int initialized) {
836 GrowableArray<Method*> mirandas(20);
837 get_mirandas(&mirandas, NULL, ik()->super(), ik()->methods(),
838 ik()->default_methods(), ik()->local_interfaces());
839 for (int i = 0; i < mirandas.length(); i++) {
840 if (PrintVtables && Verbose) {
841 Method* meth = mirandas.at(i);
842 ResourceMark rm(Thread::current());
843 if (meth != NULL) {
844 char* sig = meth->name_and_sig_as_C_string();
845 tty->print("fill in mirandas with %s index %d, flags: ",
846 sig, initialized);
847 meth->access_flags().print_on(tty);
848 if (meth->is_default_method()) {
849 tty->print("default ");
850 }
851 tty->cr();
852 }
853 }
854 put_method_at(mirandas.at(i), initialized);
855 ++initialized;
856 }
857 return initialized;
858 }
859
860 // Copy this class's vtable to the vtable beginning at start.
861 // Used to copy superclass vtable to prefix of subclass's vtable.
862 void klassVtable::copy_vtable_to(vtableEntry* start) {
863 Copy::disjoint_words((HeapWord*)table(), (HeapWord*)start, _length * vtableEntry::size());
864 }
865
866 #if INCLUDE_JVMTI
867 bool klassVtable::adjust_default_method(int vtable_index, Method* old_method, Method* new_method) {
868 // If old_method is default, find this vtable index in default_vtable_indices
869 // and replace that method in the _default_methods list
870 bool updated = false;
871
872 Array<Method*>* default_methods = ik()->default_methods();
873 if (default_methods != NULL) {
874 int len = default_methods->length();
875 for (int idx = 0; idx < len; idx++) {
876 if (vtable_index == ik()->default_vtable_indices()->at(idx)) {
877 if (default_methods->at(idx) == old_method) {
878 default_methods->at_put(idx, new_method);
879 updated = true;
880 }
881 break;
882 }
883 }
884 }
885 return updated;
886 }
887
888 // search the vtable for uses of either obsolete or EMCP methods
889 void klassVtable::adjust_method_entries(InstanceKlass* holder, bool * trace_name_printed) {
890 int prn_enabled = 0;
891 for (int index = 0; index < length(); index++) {
892 Method* old_method = unchecked_method_at(index);
893 if (old_method == NULL || old_method->method_holder() != holder || !old_method->is_old()) {
894 continue; // skip uninteresting entries
895 }
896 assert(!old_method->is_deleted(), "vtable methods may not be deleted");
897
898 Method* new_method = holder->method_with_idnum(old_method->orig_method_idnum());
899
900 assert(new_method != NULL, "method_with_idnum() should not be NULL");
901 assert(old_method != new_method, "sanity check");
902
903 put_method_at(new_method, index);
904 // For default methods, need to update the _default_methods array
905 // which can only have one method entry for a given signature
906 bool updated_default = false;
907 if (old_method->is_default_method()) {
908 updated_default = adjust_default_method(index, old_method, new_method);
909 }
910
911 if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
912 if (!(*trace_name_printed)) {
913 // RC_TRACE_MESG macro has an embedded ResourceMark
914 RC_TRACE_MESG(("adjust: klassname=%s for methods from name=%s",
915 klass()->external_name(),
916 old_method->method_holder()->external_name()));
917 *trace_name_printed = true;
918 }
919 // RC_TRACE macro has an embedded ResourceMark
920 RC_TRACE(0x00100000, ("vtable method update: %s(%s), updated default = %s",
921 new_method->name()->as_C_string(),
922 new_method->signature()->as_C_string(),
923 updated_default ? "true" : "false"));
924 }
925 }
926 }
927
928 // a vtable should never contain old or obsolete methods
929 bool klassVtable::check_no_old_or_obsolete_entries() {
930 for (int i = 0; i < length(); i++) {
931 Method* m = unchecked_method_at(i);
932 if (m != NULL &&
933 (NOT_PRODUCT(!m->is_valid() ||) m->is_old() || m->is_obsolete())) {
934 return false;
935 }
936 }
937 return true;
938 }
939
940 void klassVtable::dump_vtable() {
941 tty->print_cr("vtable dump --");
942 for (int i = 0; i < length(); i++) {
943 Method* m = unchecked_method_at(i);
944 if (m != NULL) {
945 tty->print(" (%5d) ", i);
946 m->access_flags().print_on(tty);
947 if (m->is_default_method()) {
948 tty->print("default ");
949 }
950 if (m->is_overpass()) {
951 tty->print("overpass");
952 }
953 tty->print(" -- ");
954 m->print_name(tty);
955 tty->cr();
956 }
957 }
958 }
959 #endif // INCLUDE_JVMTI
960
961 // CDS/RedefineClasses support - clear vtables so they can be reinitialized
962 void klassVtable::clear_vtable() {
963 for (int i = 0; i < _length; i++) table()[i].clear();
964 }
965
966 bool klassVtable::is_initialized() {
967 return _length == 0 || table()[0].method() != NULL;
968 }
969
970 //-----------------------------------------------------------------------------------------
971 // Itable code
972
973 // Initialize a itableMethodEntry
974 void itableMethodEntry::initialize(Method* m) {
975 if (m == NULL) return;
976
977 _method = m;
978 }
979
980 klassItable::klassItable(instanceKlassHandle klass) {
981 _klass = klass;
982
983 if (klass->itable_length() > 0) {
984 itableOffsetEntry* offset_entry = (itableOffsetEntry*)klass->start_of_itable();
985 if (offset_entry != NULL && offset_entry->interface_klass() != NULL) { // Check that itable is initialized
986 // First offset entry points to the first method_entry
987 intptr_t* method_entry = (intptr_t *)(((address)klass()) + offset_entry->offset());
988 intptr_t* end = klass->end_of_itable();
989
990 _table_offset = (intptr_t*)offset_entry - (intptr_t*)klass();
991 _size_offset_table = (method_entry - ((intptr_t*)offset_entry)) / itableOffsetEntry::size();
992 _size_method_table = (end - method_entry) / itableMethodEntry::size();
993 assert(_table_offset >= 0 && _size_offset_table >= 0 && _size_method_table >= 0, "wrong computation");
994 return;
995 }
996 }
997
998 // The length of the itable was either zero, or it has not yet been initialized.
999 _table_offset = 0;
1000 _size_offset_table = 0;
1001 _size_method_table = 0;
1002 }
1003
1004 static int initialize_count = 0;
1005
1006 // Initialization
1007 void klassItable::initialize_itable(bool checkconstraints, TRAPS) {
1008 if (_klass->is_interface()) {
1009 // This needs to go after vtable indices are assigned but
1010 // before implementors need to know the number of itable indices.
1011 assign_itable_indices_for_interface(_klass());
1012 }
1013
1014 // Cannot be setup doing bootstrapping, interfaces don't have
1015 // itables, and klass with only ones entry have empty itables
1016 if (Universe::is_bootstrapping() ||
1017 _klass->is_interface() ||
1018 _klass->itable_length() == itableOffsetEntry::size()) return;
1019
1020 // There's alway an extra itable entry so we can null-terminate it.
1021 guarantee(size_offset_table() >= 1, "too small");
1022 int num_interfaces = size_offset_table() - 1;
1023 if (num_interfaces > 0) {
1024 if (TraceItables) tty->print_cr("%3d: Initializing itables for %s", ++initialize_count,
1025 _klass->name()->as_C_string());
1026
1027
1028 // Iterate through all interfaces
1029 int i;
1030 for(i = 0; i < num_interfaces; i++) {
1031 itableOffsetEntry* ioe = offset_entry(i);
1032 HandleMark hm(THREAD);
1033 KlassHandle interf_h (THREAD, ioe->interface_klass());
1034 assert(interf_h() != NULL && ioe->offset() != 0, "bad offset entry in itable");
1035 initialize_itable_for_interface(ioe->offset(), interf_h, checkconstraints, CHECK);
1036 }
1037
1038 }
1039 // Check that the last entry is empty
1040 itableOffsetEntry* ioe = offset_entry(size_offset_table() - 1);
1041 guarantee(ioe->interface_klass() == NULL && ioe->offset() == 0, "terminator entry missing");
1042 }
1043
1044
1045 inline bool interface_method_needs_itable_index(Method* m) {
1046 if (m->is_static()) return false; // e.g., Stream.empty
1047 if (m->is_initializer()) return false; // <init> or <clinit>
1048 // If an interface redeclares a method from java.lang.Object,
1049 // it should already have a vtable index, don't touch it.
1050 // e.g., CharSequence.toString (from initialize_vtable)
1051 // if (m->has_vtable_index()) return false; // NO!
1052 return true;
1053 }
1054
1055 int klassItable::assign_itable_indices_for_interface(Klass* klass) {
1056 // an interface does not have an itable, but its methods need to be numbered
1057 if (TraceItables) tty->print_cr("%3d: Initializing itable indices for interface %s", ++initialize_count,
1058 klass->name()->as_C_string());
1059 Array<Method*>* methods = InstanceKlass::cast(klass)->methods();
1060 int nof_methods = methods->length();
1061 int ime_num = 0;
1062 for (int i = 0; i < nof_methods; i++) {
1063 Method* m = methods->at(i);
1064 if (interface_method_needs_itable_index(m)) {
1065 assert(!m->is_final_method(), "no final interface methods");
1066 // If m is already assigned a vtable index, do not disturb it.
1067 if (TraceItables && Verbose) {
1068 ResourceMark rm;
1069 const char* sig = (m != NULL) ? m->name_and_sig_as_C_string() : "<NULL>";
1070 if (m->has_vtable_index()) {
1071 tty->print("vtable index %d for method: %s, flags: ", m->vtable_index(), sig);
1072 } else {
1073 tty->print("itable index %d for method: %s, flags: ", ime_num, sig);
1074 }
1075 if (m != NULL) {
1076 m->access_flags().print_on(tty);
1077 if (m->is_default_method()) {
1078 tty->print("default ");
1079 }
1080 if (m->is_overpass()) {
1081 tty->print("overpass");
1082 }
1083 }
1084 tty->cr();
1085 }
1086 if (!m->has_vtable_index()) {
1087 assert(m->vtable_index() == Method::pending_itable_index, "set by initialize_vtable");
1088 m->set_itable_index(ime_num);
1089 // Progress to next itable entry
1090 ime_num++;
1091 }
1092 }
1093 }
1094 assert(ime_num == method_count_for_interface(klass), "proper sizing");
1095 return ime_num;
1096 }
1097
1098 int klassItable::method_count_for_interface(Klass* interf) {
1099 assert(interf->oop_is_instance(), "must be");
1100 assert(interf->is_interface(), "must be");
1101 Array<Method*>* methods = InstanceKlass::cast(interf)->methods();
1102 int nof_methods = methods->length();
1103 int length = 0;
1104 while (nof_methods > 0) {
1105 Method* m = methods->at(nof_methods-1);
1106 if (m->has_itable_index()) {
1107 length = m->itable_index() + 1;
1108 break;
1109 }
1110 nof_methods -= 1;
1111 }
1112 #ifdef ASSERT
1113 int nof_methods_copy = nof_methods;
1114 while (nof_methods_copy > 0) {
1115 Method* mm = methods->at(--nof_methods_copy);
1116 assert(!mm->has_itable_index() || mm->itable_index() < length, "");
1117 }
1118 #endif //ASSERT
1119 // return the rightmost itable index, plus one; or 0 if no methods have
1120 // itable indices
1121 return length;
1122 }
1123
1124
1125 void klassItable::initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS) {
1126 Array<Method*>* methods = InstanceKlass::cast(interf_h())->methods();
1127 int nof_methods = methods->length();
1128 HandleMark hm;
1129 assert(nof_methods > 0, "at least one method must exist for interface to be in vtable");
1130 Handle interface_loader (THREAD, InstanceKlass::cast(interf_h())->class_loader());
1131
1132 int ime_count = method_count_for_interface(interf_h());
1133 for (int i = 0; i < nof_methods; i++) {
1134 Method* m = methods->at(i);
1135 methodHandle target;
1136 if (m->has_itable_index()) {
1137 // This search must match the runtime resolution, i.e. selection search for invokeinterface
1138 // to correctly enforce loader constraints for interface method inheritance
1139 target = LinkResolver::lookup_instance_method_in_klasses(_klass, m->name(), m->signature(), CHECK);
1140 }
1141 if (target == NULL || !target->is_public() || target->is_abstract()) {
1142 // Entry does not resolve. Leave it empty for AbstractMethodError.
1143 if (!(target == NULL) && !target->is_public()) {
1144 // Stuff an IllegalAccessError throwing method in there instead.
1145 itableOffsetEntry::method_entry(_klass(), method_table_offset)[m->itable_index()].
1146 initialize(Universe::throw_illegal_access_error());
1147 }
1148 } else {
1149 // Entry did resolve, check loader constraints before initializing
1150 // if checkconstraints requested
1151 if (checkconstraints) {
1152 Handle method_holder_loader (THREAD, target->method_holder()->class_loader());
1153 if (method_holder_loader() != interface_loader()) {
1154 ResourceMark rm(THREAD);
1155 Symbol* failed_type_symbol =
1156 SystemDictionary::check_signature_loaders(m->signature(),
1157 method_holder_loader,
1158 interface_loader,
1159 true, CHECK);
1160 if (failed_type_symbol != NULL) {
1161 const char* msg = "loader constraint violation in interface "
1162 "itable initialization: when resolving method \"%s\" the class"
1163 " loader (instance of %s) of the current class, %s, "
1164 "and the class loader (instance of %s) for interface "
1165 "%s have different Class objects for the type %s "
1166 "used in the signature";
1167 char* sig = target()->name_and_sig_as_C_string();
1168 const char* loader1 = SystemDictionary::loader_name(method_holder_loader());
1169 char* current = _klass->name()->as_C_string();
1170 const char* loader2 = SystemDictionary::loader_name(interface_loader());
1171 char* iface = InstanceKlass::cast(interf_h())->name()->as_C_string();
1172 char* failed_type_name = failed_type_symbol->as_C_string();
1173 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
1174 strlen(current) + strlen(loader2) + strlen(iface) +
1175 strlen(failed_type_name);
1176 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
1177 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2,
1178 iface, failed_type_name);
1179 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
1180 }
1181 }
1182 }
1183
1184 // ime may have moved during GC so recalculate address
1185 int ime_num = m->itable_index();
1186 assert(ime_num < ime_count, "oob");
1187 itableOffsetEntry::method_entry(_klass(), method_table_offset)[ime_num].initialize(target());
1188 if (TraceItables && Verbose) {
1189 ResourceMark rm(THREAD);
1190 if (target() != NULL) {
1191 char* sig = target()->name_and_sig_as_C_string();
1192 tty->print("interface: %s, ime_num: %d, target: %s, method_holder: %s ",
1193 interf_h()->internal_name(), ime_num, sig,
1194 target()->method_holder()->internal_name());
1195 tty->print("target_method flags: ");
1196 target()->access_flags().print_on(tty);
1197 if (target()->is_default_method()) {
1198 tty->print("default ");
1199 }
1200 tty->cr();
1201 }
1202 }
1203 }
1204 }
1205 }
1206
1207 // Update entry for specific Method*
1208 void klassItable::initialize_with_method(Method* m) {
1209 itableMethodEntry* ime = method_entry(0);
1210 for(int i = 0; i < _size_method_table; i++) {
1211 if (ime->method() == m) {
1212 ime->initialize(m);
1213 }
1214 ime++;
1215 }
1216 }
1217
1218 #if INCLUDE_JVMTI
1219 // search the itable for uses of either obsolete or EMCP methods
1220 void klassItable::adjust_method_entries(InstanceKlass* holder, bool * trace_name_printed) {
1221
1222 itableMethodEntry* ime = method_entry(0);
1223 for (int i = 0; i < _size_method_table; i++, ime++) {
1224 Method* old_method = ime->method();
1225 if (old_method == NULL || old_method->method_holder() != holder || !old_method->is_old()) {
1226 continue; // skip uninteresting entries
1227 }
1228 assert(!old_method->is_deleted(), "itable methods may not be deleted");
1229
1230 Method* new_method = holder->method_with_idnum(old_method->orig_method_idnum());
1231
1232 assert(new_method != NULL, "method_with_idnum() should not be NULL");
1233 assert(old_method != new_method, "sanity check");
1234
1235 ime->initialize(new_method);
1236
1237 if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
1238 if (!(*trace_name_printed)) {
1239 // RC_TRACE_MESG macro has an embedded ResourceMark
1240 RC_TRACE_MESG(("adjust: name=%s",
1241 old_method->method_holder()->external_name()));
1242 *trace_name_printed = true;
1243 }
1244 // RC_TRACE macro has an embedded ResourceMark
1245 RC_TRACE(0x00200000, ("itable method update: %s(%s)",
1246 new_method->name()->as_C_string(),
1247 new_method->signature()->as_C_string()));
1248 }
1249 }
1250 }
1251
1252 // an itable should never contain old or obsolete methods
1253 bool klassItable::check_no_old_or_obsolete_entries() {
1254 itableMethodEntry* ime = method_entry(0);
1255 for (int i = 0; i < _size_method_table; i++) {
1256 Method* m = ime->method();
1257 if (m != NULL &&
1258 (NOT_PRODUCT(!m->is_valid() ||) m->is_old() || m->is_obsolete())) {
1259 return false;
1260 }
1261 ime++;
1262 }
1263 return true;
1264 }
1265
1266 void klassItable::dump_itable() {
1267 itableMethodEntry* ime = method_entry(0);
1268 tty->print_cr("itable dump --");
1269 for (int i = 0; i < _size_method_table; i++) {
1270 Method* m = ime->method();
1271 if (m != NULL) {
1272 tty->print(" (%5d) ", i);
1273 m->access_flags().print_on(tty);
1274 if (m->is_default_method()) {
1275 tty->print("default ");
1276 }
1277 tty->print(" -- ");
1278 m->print_name(tty);
1279 tty->cr();
1280 }
1281 ime++;
1282 }
1283 }
1284 #endif // INCLUDE_JVMTI
1285
1286
1287 // Setup
1288 class InterfaceVisiterClosure : public StackObj {
1289 public:
1290 virtual void doit(Klass* intf, int method_count) = 0;
1291 };
1292
1293 // Visit all interfaces with at least one itable method
1294 void visit_all_interfaces(Array<Klass*>* transitive_intf, InterfaceVisiterClosure *blk) {
1295 // Handle array argument
1296 for(int i = 0; i < transitive_intf->length(); i++) {
1297 Klass* intf = transitive_intf->at(i);
1298 assert(intf->is_interface(), "sanity check");
1299
1300 // Find no. of itable methods
1301 int method_count = 0;
1302 // method_count = klassItable::method_count_for_interface(intf);
1303 Array<Method*>* methods = InstanceKlass::cast(intf)->methods();
1304 if (methods->length() > 0) {
1305 for (int i = methods->length(); --i >= 0; ) {
1306 if (interface_method_needs_itable_index(methods->at(i))) {
1307 method_count++;
1308 }
1309 }
1310 }
1311
1312 // Only count interfaces with at least one method
1313 if (method_count > 0) {
1314 blk->doit(intf, method_count);
1315 }
1316 }
1317 }
1318
1319 class CountInterfacesClosure : public InterfaceVisiterClosure {
1320 private:
1321 int _nof_methods;
1322 int _nof_interfaces;
1323 public:
1324 CountInterfacesClosure() { _nof_methods = 0; _nof_interfaces = 0; }
1325
1326 int nof_methods() const { return _nof_methods; }
1327 int nof_interfaces() const { return _nof_interfaces; }
1328
1329 void doit(Klass* intf, int method_count) { _nof_methods += method_count; _nof_interfaces++; }
1330 };
1331
1332 class SetupItableClosure : public InterfaceVisiterClosure {
1333 private:
1334 itableOffsetEntry* _offset_entry;
1335 itableMethodEntry* _method_entry;
1336 address _klass_begin;
1337 public:
1338 SetupItableClosure(address klass_begin, itableOffsetEntry* offset_entry, itableMethodEntry* method_entry) {
1339 _klass_begin = klass_begin;
1340 _offset_entry = offset_entry;
1341 _method_entry = method_entry;
1342 }
1343
1344 itableMethodEntry* method_entry() const { return _method_entry; }
1345
1346 void doit(Klass* intf, int method_count) {
1347 int offset = ((address)_method_entry) - _klass_begin;
1348 _offset_entry->initialize(intf, offset);
1349 _offset_entry++;
1350 _method_entry += method_count;
1351 }
1352 };
1353
1354 int klassItable::compute_itable_size(Array<Klass*>* transitive_interfaces) {
1355 // Count no of interfaces and total number of interface methods
1356 CountInterfacesClosure cic;
1357 visit_all_interfaces(transitive_interfaces, &cic);
1358
1359 // There's alway an extra itable entry so we can null-terminate it.
1360 int itable_size = calc_itable_size(cic.nof_interfaces() + 1, cic.nof_methods());
1361
1362 // Statistics
1363 update_stats(itable_size * HeapWordSize);
1364
1365 return itable_size;
1366 }
1367
1368
1369 // Fill out offset table and interface klasses into the itable space
1370 void klassItable::setup_itable_offset_table(instanceKlassHandle klass) {
1371 if (klass->itable_length() == 0) return;
1372 assert(!klass->is_interface(), "Should have zero length itable");
1373
1374 // Count no of interfaces and total number of interface methods
1375 CountInterfacesClosure cic;
1376 visit_all_interfaces(klass->transitive_interfaces(), &cic);
1377 int nof_methods = cic.nof_methods();
1378 int nof_interfaces = cic.nof_interfaces();
1379
1380 // Add one extra entry so we can null-terminate the table
1381 nof_interfaces++;
1382
1383 assert(compute_itable_size(klass->transitive_interfaces()) ==
1384 calc_itable_size(nof_interfaces, nof_methods),
1385 "mismatch calculation of itable size");
1386
1387 // Fill-out offset table
1388 itableOffsetEntry* ioe = (itableOffsetEntry*)klass->start_of_itable();
1389 itableMethodEntry* ime = (itableMethodEntry*)(ioe + nof_interfaces);
1390 intptr_t* end = klass->end_of_itable();
1391 assert((oop*)(ime + nof_methods) <= (oop*)klass->start_of_nonstatic_oop_maps(), "wrong offset calculation (1)");
1392 assert((oop*)(end) == (oop*)(ime + nof_methods), "wrong offset calculation (2)");
1393
1394 // Visit all interfaces and initialize itable offset table
1395 SetupItableClosure sic((address)klass(), ioe, ime);
1396 visit_all_interfaces(klass->transitive_interfaces(), &sic);
1397
1398 #ifdef ASSERT
1399 ime = sic.method_entry();
1400 oop* v = (oop*) klass->end_of_itable();
1401 assert( (oop*)(ime) == v, "wrong offset calculation (2)");
1402 #endif
1403 }
1404
1405
1406 // inverse to itable_index
1407 Method* klassItable::method_for_itable_index(Klass* intf, int itable_index) {
1408 assert(InstanceKlass::cast(intf)->is_interface(), "sanity check");
1409 assert(intf->verify_itable_index(itable_index), "");
1410 Array<Method*>* methods = InstanceKlass::cast(intf)->methods();
1411
1412 if (itable_index < 0 || itable_index >= method_count_for_interface(intf))
1413 return NULL; // help caller defend against bad indices
1414
1415 int index = itable_index;
1416 Method* m = methods->at(index);
1417 int index2 = -1;
1418 while (!m->has_itable_index() ||
1419 (index2 = m->itable_index()) != itable_index) {
1420 assert(index2 < itable_index, "monotonic");
1421 if (++index == methods->length())
1422 return NULL;
1423 m = methods->at(index);
1424 }
1425 assert(m->itable_index() == itable_index, "correct inverse");
1426
1427 return m;
1428 }
1429
1430 void klassVtable::verify(outputStream* st, bool forced) {
1431 // make sure table is initialized
1432 if (!Universe::is_fully_initialized()) return;
1433 #ifndef PRODUCT
1434 // avoid redundant verifies
1435 if (!forced && _verify_count == Universe::verify_count()) return;
1436 _verify_count = Universe::verify_count();
1437 #endif
1438 oop* end_of_obj = (oop*)_klass() + _klass()->size();
1439 oop* end_of_vtable = (oop *)&table()[_length];
1440 if (end_of_vtable > end_of_obj) {
1441 fatal(err_msg("klass %s: klass object too short (vtable extends beyond "
1442 "end)", _klass->internal_name()));
1443 }
1444
1445 for (int i = 0; i < _length; i++) table()[i].verify(this, st);
1446 // verify consistency with superKlass vtable
1447 Klass* super = _klass->super();
1448 if (super != NULL) {
1449 InstanceKlass* sk = InstanceKlass::cast(super);
1450 klassVtable* vt = sk->vtable();
1451 for (int i = 0; i < vt->length(); i++) {
1452 verify_against(st, vt, i);
1453 }
1454 }
1455 }
1456
1457 void klassVtable::verify_against(outputStream* st, klassVtable* vt, int index) {
1458 vtableEntry* vte = &vt->table()[index];
1459 if (vte->method()->name() != table()[index].method()->name() ||
1460 vte->method()->signature() != table()[index].method()->signature()) {
1461 fatal("mismatched name/signature of vtable entries");
1462 }
1463 }
1464
1465 #ifndef PRODUCT
1466 void klassVtable::print() {
1467 ResourceMark rm;
1468 tty->print("klassVtable for klass %s (length %d):\n", _klass->internal_name(), length());
1469 for (int i = 0; i < length(); i++) {
1470 table()[i].print();
1471 tty->cr();
1472 }
1473 }
1474 #endif
1475
1476 void vtableEntry::verify(klassVtable* vt, outputStream* st) {
1477 NOT_PRODUCT(FlagSetting fs(IgnoreLockingAssertions, true));
1478 assert(method() != NULL, "must have set method");
1479 method()->verify();
1480 // we sub_type, because it could be a miranda method
1481 if (!vt->klass()->is_subtype_of(method()->method_holder())) {
1482 #ifndef PRODUCT
1483 print();
1484 #endif
1485 fatal(err_msg("vtableEntry " PTR_FORMAT ": method is from subclass", this));
1486 }
1487 }
1488
1489 #ifndef PRODUCT
1490
1491 void vtableEntry::print() {
1492 ResourceMark rm;
1493 tty->print("vtableEntry %s: ", method()->name()->as_C_string());
1494 if (Verbose) {
1495 tty->print("m %#lx ", (address)method());
1496 }
1497 }
1498
1499 class VtableStats : AllStatic {
1500 public:
1501 static int no_klasses; // # classes with vtables
1502 static int no_array_klasses; // # array classes
1503 static int no_instance_klasses; // # instanceKlasses
1504 static int sum_of_vtable_len; // total # of vtable entries
1505 static int sum_of_array_vtable_len; // total # of vtable entries in array klasses only
1506 static int fixed; // total fixed overhead in bytes
1507 static int filler; // overhead caused by filler bytes
1508 static int entries; // total bytes consumed by vtable entries
1509 static int array_entries; // total bytes consumed by array vtable entries
1510
1511 static void do_class(Klass* k) {
1512 Klass* kl = k;
1513 klassVtable* vt = kl->vtable();
1514 if (vt == NULL) return;
1515 no_klasses++;
1516 if (kl->oop_is_instance()) {
1517 no_instance_klasses++;
1518 kl->array_klasses_do(do_class);
1519 }
1520 if (kl->oop_is_array()) {
1521 no_array_klasses++;
1522 sum_of_array_vtable_len += vt->length();
1523 }
1524 sum_of_vtable_len += vt->length();
1525 }
1526
1527 static void compute() {
1528 SystemDictionary::classes_do(do_class);
1529 fixed = no_klasses * oopSize; // vtable length
1530 // filler size is a conservative approximation
1531 filler = oopSize * (no_klasses - no_instance_klasses) * (sizeof(InstanceKlass) - sizeof(ArrayKlass) - 1);
1532 entries = sizeof(vtableEntry) * sum_of_vtable_len;
1533 array_entries = sizeof(vtableEntry) * sum_of_array_vtable_len;
1534 }
1535 };
1536
1537 int VtableStats::no_klasses = 0;
1538 int VtableStats::no_array_klasses = 0;
1539 int VtableStats::no_instance_klasses = 0;
1540 int VtableStats::sum_of_vtable_len = 0;
1541 int VtableStats::sum_of_array_vtable_len = 0;
1542 int VtableStats::fixed = 0;
1543 int VtableStats::filler = 0;
1544 int VtableStats::entries = 0;
1545 int VtableStats::array_entries = 0;
1546
1547 void klassVtable::print_statistics() {
1548 ResourceMark rm;
1549 HandleMark hm;
1550 VtableStats::compute();
1551 tty->print_cr("vtable statistics:");
1552 tty->print_cr("%6d classes (%d instance, %d array)", VtableStats::no_klasses, VtableStats::no_instance_klasses, VtableStats::no_array_klasses);
1553 int total = VtableStats::fixed + VtableStats::filler + VtableStats::entries;
1554 tty->print_cr("%6d bytes fixed overhead (refs + vtable object header)", VtableStats::fixed);
1555 tty->print_cr("%6d bytes filler overhead", VtableStats::filler);
1556 tty->print_cr("%6d bytes for vtable entries (%d for arrays)", VtableStats::entries, VtableStats::array_entries);
1557 tty->print_cr("%6d bytes total", total);
1558 }
1559
1560 int klassItable::_total_classes; // Total no. of classes with itables
1561 long klassItable::_total_size; // Total no. of bytes used for itables
1562
1563 void klassItable::print_statistics() {
1564 tty->print_cr("itable statistics:");
1565 tty->print_cr("%6d classes with itables", _total_classes);
1566 tty->print_cr("%6d K uses for itables (average by class: %d bytes)", _total_size / K, _total_size / _total_classes);
1567 }
1568
1569 #endif // PRODUCT