1 /*
2 * Copyright (c) 1997, 2014, 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_implementation/shared/markSweep.inline.hpp"
29 #include "interpreter/linkResolver.hpp"
30 #include "memory/gcLocker.hpp"
31 #include "memory/resourceArea.hpp"
32 #include "memory/universe.inline.hpp"
33 #include "oops/instanceKlass.hpp"
34 #include "oops/klassVtable.hpp"
35 #include "oops/method.hpp"
36 #include "oops/objArrayOop.hpp"
37 #include "oops/oop.inline.hpp"
38 #include "prims/jvmtiRedefineClassesTrace.hpp"
39 #include "runtime/arguments.hpp"
40 #include "runtime/handles.inline.hpp"
41 #include "utilities/copy.hpp"
42
43 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
44
45 inline InstanceKlass* klassVtable::ik() const {
46 Klass* k = _klass();
47 assert(k->oop_is_instance(), "not an InstanceKlass");
48 return (InstanceKlass*)k;
49 }
50
51
52 // this function computes the vtable size (including the size needed for miranda
53 // methods) and the number of miranda methods in this class.
54 // Note on Miranda methods: Let's say there is a class C that implements
55 // interface I, and none of C's superclasses implements I.
56 // Let's say there is an abstract method m in I that neither C
57 // nor any of its super classes implement (i.e there is no method of any access,
58 // with the same name and signature as m), then m is a Miranda method which is
59 // entered as a public abstract method in C's vtable. From then on it should
60 // treated as any other public method in C for method over-ride purposes.
61 void klassVtable::compute_vtable_size_and_num_mirandas(
62 int* vtable_length_ret, int* num_new_mirandas,
63 GrowableArray<Method*>* all_mirandas, Klass* super,
64 Array<Method*>* methods, AccessFlags class_flags,
65 Handle classloader, Symbol* classname, Array<Klass*>* local_interfaces,
66 TRAPS) {
67 No_Safepoint_Verifier nsv;
68
69 // set up default result values
70 int vtable_length = 0;
71
72 // start off with super's vtable length
73 InstanceKlass* sk = (InstanceKlass*)super;
74 vtable_length = super == NULL ? 0 : sk->vtable_length();
75
76 // go thru each method in the methods table to see if it needs a new entry
77 int len = methods->length();
78 for (int i = 0; i < len; i++) {
79 assert(methods->at(i)->is_method(), "must be a Method*");
80 methodHandle mh(THREAD, methods->at(i));
81
82 if (needs_new_vtable_entry(mh, super, classloader, classname, class_flags, THREAD)) {
83 vtable_length += vtableEntry::size(); // we need a new entry
84 }
85 }
86
87 GrowableArray<Method*> new_mirandas(20);
88 // compute the number of mirandas methods that must be added to the end
89 get_mirandas(&new_mirandas, all_mirandas, super, methods, NULL, local_interfaces);
90 *num_new_mirandas = new_mirandas.length();
91
92 // Interfaces do not need interface methods in their vtables
93 // This includes miranda methods and during later processing, default methods
94 if (!class_flags.is_interface()) {
95 vtable_length += *num_new_mirandas * vtableEntry::size();
96 }
97
98 if (Universe::is_bootstrapping() && vtable_length == 0) {
99 // array classes don't have their superclass set correctly during
100 // bootstrapping
101 vtable_length = Universe::base_vtable_size();
102 }
103
104 if (super == NULL && !Universe::is_bootstrapping() &&
105 vtable_length != Universe::base_vtable_size()) {
106 // Someone is attempting to redefine java.lang.Object incorrectly. The
107 // only way this should happen is from
108 // SystemDictionary::resolve_from_stream(), which will detect this later
109 // and throw a security exception. So don't assert here to let
110 // the exception occur.
111 vtable_length = Universe::base_vtable_size();
112 }
113 assert(super != NULL || vtable_length == Universe::base_vtable_size(),
114 "bad vtable size for class Object");
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 if (is_default
406 || ((super_klass->is_override(super_method, target_loader, target_classname, THREAD))
407 || ((klass->major_version() >= VTABLE_TRANSITIVE_OVERRIDE_VERSION)
408 && ((super_klass = find_transitive_override(super_klass,
409 target_method, i, target_loader,
410 target_classname, THREAD))
411 != (InstanceKlass*)NULL))))
412 {
413 // Package private methods always need a new entry to root their own
414 // overriding. They may also override other methods.
415 if (!target_method()->is_package_private()) {
416 allocate_new = false;
417 }
418
419 if (checkconstraints) {
420 // Override vtable entry if passes loader constraint check
421 // if loader constraint checking requested
422 // No need to visit his super, since he and his super
423 // have already made any needed loader constraints.
424 // Since loader constraints are transitive, it is enough
425 // to link to the first super, and we get all the others.
426 Handle super_loader(THREAD, super_klass->class_loader());
427
428 if (target_loader() != super_loader()) {
429 ResourceMark rm(THREAD);
430 Symbol* failed_type_symbol =
431 SystemDictionary::check_signature_loaders(signature, target_loader,
432 super_loader, true,
433 CHECK_(false));
434 if (failed_type_symbol != NULL) {
435 const char* msg = "loader constraint violation: when resolving "
436 "overridden method \"%s\" the class loader (instance"
437 " of %s) of the current class, %s, and its superclass loader "
438 "(instance of %s), have different Class objects for the type "
439 "%s used in the signature";
440 char* sig = target_method()->name_and_sig_as_C_string();
441 const char* loader1 = SystemDictionary::loader_name(target_loader());
442 char* current = target_klass->name()->as_C_string();
443 const char* loader2 = SystemDictionary::loader_name(super_loader());
444 char* failed_type_name = failed_type_symbol->as_C_string();
445 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
446 strlen(current) + strlen(loader2) + strlen(failed_type_name);
447 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
448 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2,
449 failed_type_name);
450 THROW_MSG_(vmSymbols::java_lang_LinkageError(), buf, false);
451 }
452 }
453 }
454
455 put_method_at(target_method(), i);
456 if (!is_default) {
457 target_method()->set_vtable_index(i);
458 } else {
459 if (def_vtable_indices != NULL) {
460 def_vtable_indices->at_put(default_index, i);
461 }
462 assert(super_method->is_default_method() || super_method->is_overpass()
463 || super_method->is_abstract(), "default override error");
464 }
465
466
467 #ifndef PRODUCT
468 if (PrintVtables && Verbose) {
469 ResourceMark rm(THREAD);
470 char* sig = target_method()->name_and_sig_as_C_string();
471 tty->print("overriding with %s::%s index %d, original flags: ",
472 target_klass->internal_name(), sig, i);
473 super_method->access_flags().print_on(tty);
474 if (super_method->is_default_method()) {
475 tty->print("default ");
476 }
477 if (super_method->is_overpass()) {
478 tty->print("overpass");
479 }
480 tty->print("overriders flags: ");
481 target_method->access_flags().print_on(tty);
482 if (target_method->is_default_method()) {
483 tty->print("default ");
484 }
485 if (target_method->is_overpass()) {
486 tty->print("overpass");
487 }
488 tty->cr();
489 }
490 #endif /*PRODUCT*/
491 } else {
492 // allocate_new = true; default. We might override one entry,
493 // but not override another. Once we override one, not need new
494 #ifndef PRODUCT
495 if (PrintVtables && Verbose) {
496 ResourceMark rm(THREAD);
497 char* sig = target_method()->name_and_sig_as_C_string();
498 tty->print("NOT overriding with %s::%s index %d, original flags: ",
499 target_klass->internal_name(), sig,i);
500 super_method->access_flags().print_on(tty);
501 if (super_method->is_default_method()) {
502 tty->print("default ");
503 }
504 if (super_method->is_overpass()) {
505 tty->print("overpass");
506 }
507 tty->print("overriders flags: ");
508 target_method->access_flags().print_on(tty);
509 if (target_method->is_default_method()) {
510 tty->print("default ");
511 }
512 if (target_method->is_overpass()) {
513 tty->print("overpass");
514 }
515 tty->cr();
516 }
517 #endif /*PRODUCT*/
518 }
519 }
520 }
521 return allocate_new;
522 }
523
524 void klassVtable::put_method_at(Method* m, int index) {
525 #ifndef PRODUCT
526 if (PrintVtables && Verbose) {
527 ResourceMark rm;
528 const char* sig = (m != NULL) ? m->name_and_sig_as_C_string() : "<NULL>";
529 tty->print("adding %s at index %d, flags: ", sig, index);
530 if (m != NULL) {
531 m->access_flags().print_on(tty);
532 if (m->is_default_method()) {
533 tty->print("default ");
534 }
535 if (m->is_overpass()) {
536 tty->print("overpass");
537 }
538 }
539 tty->cr();
540 }
541 #endif
542 table()[index].set(m);
543 }
544
545 // Find out if a method "m" with superclass "super", loader "classloader" and
546 // name "classname" needs a new vtable entry. Let P be a class package defined
547 // by "classloader" and "classname".
548 // NOTE: The logic used here is very similar to the one used for computing
549 // the vtables indices for a method. We cannot directly use that function because,
550 // we allocate the InstanceKlass at load time, and that requires that the
551 // superclass has been loaded.
552 // However, the vtable entries are filled in at link time, and therefore
553 // the superclass' vtable may not yet have been filled in.
554 bool klassVtable::needs_new_vtable_entry(methodHandle target_method,
555 Klass* super,
556 Handle classloader,
557 Symbol* classname,
558 AccessFlags class_flags,
559 TRAPS) {
560 if (class_flags.is_interface()) {
561 // Interfaces do not use vtables, except for java.lang.Object methods,
562 // so there is no point to assigning
563 // a vtable index to any of their local methods. If we refrain from doing this,
564 // we can use Method::_vtable_index to hold the itable index
565 return false;
566 }
567
568 if (target_method->is_final_method(class_flags) ||
569 // a final method never needs a new entry; final methods can be statically
570 // resolved and they have to be present in the vtable only if they override
571 // a super's method, in which case they re-use its entry
572 (target_method()->is_static()) ||
573 // static methods don't need to be in vtable
574 (target_method()->name() == vmSymbols::object_initializer_name())
575 // <init> is never called dynamically-bound
576 ) {
577 return false;
578 }
579
580 // Concrete interface methods do not need new entries, they override
581 // abstract method entries using default inheritance rules
582 if (target_method()->method_holder() != NULL &&
583 target_method()->method_holder()->is_interface() &&
584 !target_method()->is_abstract() ) {
585 return false;
586 }
587
588 // we need a new entry if there is no superclass
589 if (super == NULL) {
590 return true;
591 }
592
593 // private methods in classes always have a new entry in the vtable
594 // specification interpretation since classic has
595 // private methods not overriding
596 // JDK8 adds private methods in interfaces which require invokespecial
597 if (target_method()->is_private()) {
598 return true;
599 }
600
601 // Package private methods always need a new entry to root their own
602 // overriding. This allows transitive overriding to work.
603 if (target_method()->is_package_private()) {
604 return true;
605 }
606
607 // search through the super class hierarchy to see if we need
608 // a new entry
609 ResourceMark rm;
610 Symbol* name = target_method()->name();
611 Symbol* signature = target_method()->signature();
612 Klass* k = super;
613 Method* super_method = NULL;
614 InstanceKlass *holder = NULL;
615 Method* recheck_method = NULL;
616 while (k != NULL) {
617 // lookup through the hierarchy for a method with matching name and sign.
618 super_method = InstanceKlass::cast(k)->lookup_method(name, signature);
619 if (super_method == NULL) {
620 break; // we still have to search for a matching miranda method
621 }
622 // get the class holding the matching method
623 // make sure you use that class for is_override
624 InstanceKlass* superk = super_method->method_holder();
625 // we want only instance method matches
626 // pretend private methods are not in the super vtable
627 // since we do override around them: e.g. a.m pub/b.m private/c.m pub,
628 // ignore private, c.m pub does override a.m pub
629 // For classes that were not javac'd together, we also do transitive overriding around
630 // methods that have less accessibility
631 if ((!super_method->is_static()) &&
632 (!super_method->is_private())) {
633 if (superk->is_override(super_method, classloader, classname, THREAD)) {
634 return false;
635 // else keep looking for transitive overrides
636 }
637 }
638
639 // Start with lookup result and continue to search up
640 k = superk->super(); // haven't found an override match yet; continue to look
641 }
642
643 // if the target method is public or protected it may have a matching
644 // miranda method in the super, whose entry it should re-use.
645 // Actually, to handle cases that javac would not generate, we need
646 // this check for all access permissions.
647 InstanceKlass *sk = InstanceKlass::cast(super);
648 if (sk->has_miranda_methods()) {
649 if (sk->lookup_method_in_all_interfaces(name, signature, Klass::normal) != NULL) {
650 return false; // found a matching miranda; we do not need a new entry
651 }
652 }
653 return true; // found no match; we need a new entry
654 }
655
656 // Support for miranda methods
657
658 // get the vtable index of a miranda method with matching "name" and "signature"
659 int klassVtable::index_of_miranda(Symbol* name, Symbol* signature) {
660 // search from the bottom, might be faster
661 for (int i = (length() - 1); i >= 0; i--) {
662 Method* m = table()[i].method();
663 if (is_miranda_entry_at(i) &&
664 m->name() == name && m->signature() == signature) {
665 return i;
666 }
667 }
668 return Method::invalid_vtable_index;
669 }
670
671 // check if an entry at an index is miranda
672 // requires that method m at entry be declared ("held") by an interface.
673 bool klassVtable::is_miranda_entry_at(int i) {
674 Method* m = method_at(i);
675 Klass* method_holder = m->method_holder();
676 InstanceKlass *mhk = InstanceKlass::cast(method_holder);
677
678 // miranda methods are public abstract instance interface methods in a class's vtable
679 if (mhk->is_interface()) {
680 assert(m->is_public(), "should be public");
681 assert(ik()->implements_interface(method_holder) , "this class should implement the interface");
682 // the search could find a miranda or a default method
683 if (is_miranda(m, ik()->methods(), ik()->default_methods(), ik()->super())) {
684 return true;
685 }
686 }
687 return false;
688 }
689
690 // check if a method is a miranda method, given a class's methods table,
691 // its default_method table and its super
692 // Miranda methods are calculated twice:
693 // first: before vtable size calculation: including abstract and default
694 // This is seen by default method creation
695 // Second: recalculated during vtable initialization: only abstract
696 // This is seen by link resolution and selection.
697 // "miranda" means not static, not defined by this class.
698 // private methods in interfaces do not belong in the miranda list.
699 // the caller must make sure that the method belongs to an interface implemented by the class
700 // Miranda methods only include public interface instance methods
701 // Not private methods, not static methods, not default == concrete abstract
702 // Miranda methods also do not include overpass methods in interfaces
703 bool klassVtable::is_miranda(Method* m, Array<Method*>* class_methods,
704 Array<Method*>* default_methods, Klass* super) {
705 if (m->is_static() || m->is_private() || m->is_overpass()) {
706 return false;
707 }
708 Symbol* name = m->name();
709 Symbol* signature = m->signature();
710
711 if (InstanceKlass::find_instance_method(class_methods, name, signature) == NULL) {
712 // did not find it in the method table of the current class
713 if ((default_methods == NULL) ||
714 InstanceKlass::find_method(default_methods, name, signature) == NULL) {
715 if (super == NULL) {
716 // super doesn't exist
717 return true;
718 }
719
720 Method* mo = InstanceKlass::cast(super)->lookup_method(name, signature);
721 while (mo != NULL && mo->access_flags().is_static()
722 && mo->method_holder() != NULL
723 && mo->method_holder()->super() != NULL)
724 {
725 mo = mo->method_holder()->super()->uncached_lookup_method(name, signature, Klass::normal);
726 }
727 if (mo == NULL || mo->access_flags().is_private() ) {
728 // super class hierarchy does not implement it or protection is different
729 return true;
730 }
731 }
732 }
733
734 return false;
735 }
736
737 // Scans current_interface_methods for miranda methods that do not
738 // already appear in new_mirandas, or default methods, and are also not defined-and-non-private
739 // in super (superclass). These mirandas are added to all_mirandas if it is
740 // not null; in addition, those that are not duplicates of miranda methods
741 // inherited by super from its interfaces are added to new_mirandas.
742 // Thus, new_mirandas will be the set of mirandas that this class introduces,
743 // all_mirandas will be the set of all mirandas applicable to this class
744 // including all defined in superclasses.
745 void klassVtable::add_new_mirandas_to_lists(
746 GrowableArray<Method*>* new_mirandas, GrowableArray<Method*>* all_mirandas,
747 Array<Method*>* current_interface_methods, Array<Method*>* class_methods,
748 Array<Method*>* default_methods, Klass* super) {
749
750 // iterate thru the current interface's method to see if it a miranda
751 int num_methods = current_interface_methods->length();
752 for (int i = 0; i < num_methods; i++) {
753 Method* im = current_interface_methods->at(i);
754 bool is_duplicate = false;
755 int num_of_current_mirandas = new_mirandas->length();
756 // check for duplicate mirandas in different interfaces we implement
757 for (int j = 0; j < num_of_current_mirandas; j++) {
758 Method* miranda = new_mirandas->at(j);
759 if ((im->name() == miranda->name()) &&
760 (im->signature() == miranda->signature())) {
761 is_duplicate = true;
762 break;
763 }
764 }
765
766 if (!is_duplicate) { // we don't want duplicate miranda entries in the vtable
767 if (is_miranda(im, class_methods, default_methods, super)) { // is it a miranda at all?
768 InstanceKlass *sk = InstanceKlass::cast(super);
769 // check if it is a duplicate of a super's miranda
770 if (sk->lookup_method_in_all_interfaces(im->name(), im->signature(), Klass::normal) == NULL) {
771 new_mirandas->append(im);
772 }
773 if (all_mirandas != NULL) {
774 all_mirandas->append(im);
775 }
776 }
777 }
778 }
779 }
780
781 void klassVtable::get_mirandas(GrowableArray<Method*>* new_mirandas,
782 GrowableArray<Method*>* all_mirandas,
783 Klass* super, Array<Method*>* class_methods,
784 Array<Method*>* default_methods,
785 Array<Klass*>* local_interfaces) {
786 assert((new_mirandas->length() == 0) , "current mirandas must be 0");
787
788 // iterate thru the local interfaces looking for a miranda
789 int num_local_ifs = local_interfaces->length();
790 for (int i = 0; i < num_local_ifs; i++) {
791 InstanceKlass *ik = InstanceKlass::cast(local_interfaces->at(i));
792 add_new_mirandas_to_lists(new_mirandas, all_mirandas,
793 ik->methods(), class_methods,
794 default_methods, super);
795 // iterate thru each local's super interfaces
796 Array<Klass*>* super_ifs = ik->transitive_interfaces();
797 int num_super_ifs = super_ifs->length();
798 for (int j = 0; j < num_super_ifs; j++) {
799 InstanceKlass *sik = InstanceKlass::cast(super_ifs->at(j));
800 add_new_mirandas_to_lists(new_mirandas, all_mirandas,
801 sik->methods(), class_methods,
802 default_methods, super);
803 }
804 }
805 }
806
807 // Discover miranda methods ("miranda" = "interface abstract, no binding"),
808 // and append them into the vtable starting at index initialized,
809 // return the new value of initialized.
810 // Miranda methods use vtable entries, but do not get assigned a vtable_index
811 // The vtable_index is discovered by searching from the end of the vtable
812 int klassVtable::fill_in_mirandas(int initialized) {
813 GrowableArray<Method*> mirandas(20);
814 get_mirandas(&mirandas, NULL, ik()->super(), ik()->methods(),
815 ik()->default_methods(), ik()->local_interfaces());
816 for (int i = 0; i < mirandas.length(); i++) {
817 if (PrintVtables && Verbose) {
818 Method* meth = mirandas.at(i);
819 ResourceMark rm(Thread::current());
820 if (meth != NULL) {
821 char* sig = meth->name_and_sig_as_C_string();
822 tty->print("fill in mirandas with %s index %d, flags: ",
823 sig, initialized);
824 meth->access_flags().print_on(tty);
825 if (meth->is_default_method()) {
826 tty->print("default ");
827 }
828 tty->cr();
829 }
830 }
831 put_method_at(mirandas.at(i), initialized);
832 ++initialized;
833 }
834 return initialized;
835 }
836
837 // Copy this class's vtable to the vtable beginning at start.
838 // Used to copy superclass vtable to prefix of subclass's vtable.
839 void klassVtable::copy_vtable_to(vtableEntry* start) {
840 Copy::disjoint_words((HeapWord*)table(), (HeapWord*)start, _length * vtableEntry::size());
841 }
842
843 #if INCLUDE_JVMTI
844 bool klassVtable::adjust_default_method(int vtable_index, Method* old_method, Method* new_method) {
845 // If old_method is default, find this vtable index in default_vtable_indices
846 // and replace that method in the _default_methods list
847 bool updated = false;
848
849 Array<Method*>* default_methods = ik()->default_methods();
850 if (default_methods != NULL) {
851 int len = default_methods->length();
852 for (int idx = 0; idx < len; idx++) {
853 if (vtable_index == ik()->default_vtable_indices()->at(idx)) {
854 if (default_methods->at(idx) == old_method) {
855 default_methods->at_put(idx, new_method);
856 updated = true;
857 }
858 break;
859 }
860 }
861 }
862 return updated;
863 }
864 void klassVtable::adjust_method_entries(Method** old_methods, Method** new_methods,
865 int methods_length, bool * trace_name_printed) {
866 // search the vtable for uses of either obsolete or EMCP methods
867 for (int j = 0; j < methods_length; j++) {
868 Method* old_method = old_methods[j];
869 Method* new_method = new_methods[j];
870
871 // In the vast majority of cases we could get the vtable index
872 // by using: old_method->vtable_index()
873 // However, there are rare cases, eg. sun.awt.X11.XDecoratedPeer.getX()
874 // in sun.awt.X11.XFramePeer where methods occur more than once in the
875 // vtable, so, alas, we must do an exhaustive search.
876 for (int index = 0; index < length(); index++) {
877 if (unchecked_method_at(index) == old_method) {
878 put_method_at(new_method, index);
879 // For default methods, need to update the _default_methods array
880 // which can only have one method entry for a given signature
881 bool updated_default = false;
882 if (old_method->is_default_method()) {
883 updated_default = adjust_default_method(index, old_method, new_method);
884 }
885
886 if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
887 if (!(*trace_name_printed)) {
888 // RC_TRACE_MESG macro has an embedded ResourceMark
889 RC_TRACE_MESG(("adjust: klassname=%s for methods from name=%s",
890 klass()->external_name(),
891 old_method->method_holder()->external_name()));
892 *trace_name_printed = true;
893 }
894 // RC_TRACE macro has an embedded ResourceMark
895 RC_TRACE(0x00100000, ("vtable method update: %s(%s), updated default = %s",
896 new_method->name()->as_C_string(),
897 new_method->signature()->as_C_string(),
898 updated_default ? "true" : "false"));
899 }
900 // cannot 'break' here; see for-loop comment above.
901 }
902 }
903 }
904 }
905
906 // a vtable should never contain old or obsolete methods
907 bool klassVtable::check_no_old_or_obsolete_entries() {
908 for (int i = 0; i < length(); i++) {
909 Method* m = unchecked_method_at(i);
910 if (m != NULL &&
911 (NOT_PRODUCT(!m->is_valid() ||) m->is_old() || m->is_obsolete())) {
912 return false;
913 }
914 }
915 return true;
916 }
917
918 void klassVtable::dump_vtable() {
919 tty->print_cr("vtable dump --");
920 for (int i = 0; i < length(); i++) {
921 Method* m = unchecked_method_at(i);
922 if (m != NULL) {
923 tty->print(" (%5d) ", i);
924 m->access_flags().print_on(tty);
925 if (m->is_default_method()) {
926 tty->print("default ");
927 }
928 if (m->is_overpass()) {
929 tty->print("overpass");
930 }
931 tty->print(" -- ");
932 m->print_name(tty);
933 tty->cr();
934 }
935 }
936 }
937 #endif // INCLUDE_JVMTI
938
939 // CDS/RedefineClasses support - clear vtables so they can be reinitialized
940 void klassVtable::clear_vtable() {
941 for (int i = 0; i < _length; i++) table()[i].clear();
942 }
943
944 bool klassVtable::is_initialized() {
945 return _length == 0 || table()[0].method() != NULL;
946 }
947
948 //-----------------------------------------------------------------------------------------
949 // Itable code
950
951 // Initialize a itableMethodEntry
952 void itableMethodEntry::initialize(Method* m) {
953 if (m == NULL) return;
954
955 _method = m;
956 }
957
958 klassItable::klassItable(instanceKlassHandle klass) {
959 _klass = klass;
960
961 if (klass->itable_length() > 0) {
962 itableOffsetEntry* offset_entry = (itableOffsetEntry*)klass->start_of_itable();
963 if (offset_entry != NULL && offset_entry->interface_klass() != NULL) { // Check that itable is initialized
964 // First offset entry points to the first method_entry
965 intptr_t* method_entry = (intptr_t *)(((address)klass()) + offset_entry->offset());
966 intptr_t* end = klass->end_of_itable();
967
968 _table_offset = (intptr_t*)offset_entry - (intptr_t*)klass();
969 _size_offset_table = (method_entry - ((intptr_t*)offset_entry)) / itableOffsetEntry::size();
970 _size_method_table = (end - method_entry) / itableMethodEntry::size();
971 assert(_table_offset >= 0 && _size_offset_table >= 0 && _size_method_table >= 0, "wrong computation");
972 return;
973 }
974 }
975
976 // The length of the itable was either zero, or it has not yet been initialized.
977 _table_offset = 0;
978 _size_offset_table = 0;
979 _size_method_table = 0;
980 }
981
982 static int initialize_count = 0;
983
984 // Initialization
985 void klassItable::initialize_itable(bool checkconstraints, TRAPS) {
986 if (_klass->is_interface()) {
987 // This needs to go after vtable indices are assigned but
988 // before implementors need to know the number of itable indices.
989 assign_itable_indices_for_interface(_klass());
990 }
991
992 // Cannot be setup doing bootstrapping, interfaces don't have
993 // itables, and klass with only ones entry have empty itables
994 if (Universe::is_bootstrapping() ||
995 _klass->is_interface() ||
996 _klass->itable_length() == itableOffsetEntry::size()) return;
997
998 // There's alway an extra itable entry so we can null-terminate it.
999 guarantee(size_offset_table() >= 1, "too small");
1000 int num_interfaces = size_offset_table() - 1;
1001 if (num_interfaces > 0) {
1002 if (TraceItables) tty->print_cr("%3d: Initializing itables for %s", ++initialize_count,
1003 _klass->name()->as_C_string());
1004
1005
1006 // Iterate through all interfaces
1007 int i;
1008 for(i = 0; i < num_interfaces; i++) {
1009 itableOffsetEntry* ioe = offset_entry(i);
1010 HandleMark hm(THREAD);
1011 KlassHandle interf_h (THREAD, ioe->interface_klass());
1012 assert(interf_h() != NULL && ioe->offset() != 0, "bad offset entry in itable");
1013 initialize_itable_for_interface(ioe->offset(), interf_h, checkconstraints, CHECK);
1014 }
1015
1016 }
1017 // Check that the last entry is empty
1018 itableOffsetEntry* ioe = offset_entry(size_offset_table() - 1);
1019 guarantee(ioe->interface_klass() == NULL && ioe->offset() == 0, "terminator entry missing");
1020 }
1021
1022
1023 inline bool interface_method_needs_itable_index(Method* m) {
1024 if (m->is_static()) return false; // e.g., Stream.empty
1025 if (m->is_initializer()) return false; // <init> or <clinit>
1026 // If an interface redeclares a method from java.lang.Object,
1027 // it should already have a vtable index, don't touch it.
1028 // e.g., CharSequence.toString (from initialize_vtable)
1029 // if (m->has_vtable_index()) return false; // NO!
1030 return true;
1031 }
1032
1033 int klassItable::assign_itable_indices_for_interface(Klass* klass) {
1034 // an interface does not have an itable, but its methods need to be numbered
1035 if (TraceItables) tty->print_cr("%3d: Initializing itable for interface %s", ++initialize_count,
1036 klass->name()->as_C_string());
1037 Array<Method*>* methods = InstanceKlass::cast(klass)->methods();
1038 int nof_methods = methods->length();
1039 int ime_num = 0;
1040 for (int i = 0; i < nof_methods; i++) {
1041 Method* m = methods->at(i);
1042 if (interface_method_needs_itable_index(m)) {
1043 assert(!m->is_final_method(), "no final interface methods");
1044 // If m is already assigned a vtable index, do not disturb it.
1045 if (TraceItables && Verbose) {
1046 ResourceMark rm;
1047 const char* sig = (m != NULL) ? m->name_and_sig_as_C_string() : "<NULL>";
1048 if (m->has_vtable_index()) {
1049 tty->print("itable index %d for method: %s, flags: ", m->vtable_index(), sig);
1050 } else {
1051 tty->print("itable index %d for method: %s, flags: ", ime_num, sig);
1052 }
1053 if (m != NULL) {
1054 m->access_flags().print_on(tty);
1055 if (m->is_default_method()) {
1056 tty->print("default ");
1057 }
1058 if (m->is_overpass()) {
1059 tty->print("overpass");
1060 }
1061 }
1062 tty->cr();
1063 }
1064 if (!m->has_vtable_index()) {
1065 assert(m->vtable_index() == Method::pending_itable_index, "set by initialize_vtable");
1066 m->set_itable_index(ime_num);
1067 // Progress to next itable entry
1068 ime_num++;
1069 }
1070 }
1071 }
1072 assert(ime_num == method_count_for_interface(klass), "proper sizing");
1073 return ime_num;
1074 }
1075
1076 int klassItable::method_count_for_interface(Klass* interf) {
1077 assert(interf->oop_is_instance(), "must be");
1078 assert(interf->is_interface(), "must be");
1079 Array<Method*>* methods = InstanceKlass::cast(interf)->methods();
1080 int nof_methods = methods->length();
1081 while (nof_methods > 0) {
1082 Method* m = methods->at(nof_methods-1);
1083 if (m->has_itable_index()) {
1084 int length = m->itable_index() + 1;
1085 #ifdef ASSERT
1086 while (nof_methods = 0) {
1087 m = methods->at(--nof_methods);
1088 assert(!m->has_itable_index() || m->itable_index() < length, "");
1089 }
1090 #endif //ASSERT
1091 return length; // return the rightmost itable index, plus one
1092 }
1093 nof_methods -= 1;
1094 }
1095 // no methods have itable indices
1096 return 0;
1097 }
1098
1099
1100 void klassItable::initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS) {
1101 Array<Method*>* methods = InstanceKlass::cast(interf_h())->methods();
1102 int nof_methods = methods->length();
1103 HandleMark hm;
1104 assert(nof_methods > 0, "at least one method must exist for interface to be in vtable");
1105 Handle interface_loader (THREAD, InstanceKlass::cast(interf_h())->class_loader());
1106
1107 int ime_count = method_count_for_interface(interf_h());
1108 for (int i = 0; i < nof_methods; i++) {
1109 Method* m = methods->at(i);
1110 methodHandle target;
1111 if (m->has_itable_index()) {
1112 // This search must match the runtime resolution, i.e. selection search for invokeinterface
1113 // to correctly enforce loader constraints for interface method inheritance
1114 LinkResolver::lookup_instance_method_in_klasses(target, _klass, m->name(), m->signature(), CHECK);
1115 }
1116 if (target == NULL || !target->is_public() || target->is_abstract()) {
1117 // Entry does not resolve. Leave it empty for AbstractMethodError.
1118 if (!(target == NULL) && !target->is_public()) {
1119 // Stuff an IllegalAccessError throwing method in there instead.
1120 itableOffsetEntry::method_entry(_klass(), method_table_offset)[m->itable_index()].
1121 initialize(Universe::throw_illegal_access_error());
1122 }
1123 } else {
1124 // Entry did resolve, check loader constraints before initializing
1125 // if checkconstraints requested
1126 if (checkconstraints) {
1127 Handle method_holder_loader (THREAD, target->method_holder()->class_loader());
1128 if (method_holder_loader() != interface_loader()) {
1129 ResourceMark rm(THREAD);
1130 Symbol* failed_type_symbol =
1131 SystemDictionary::check_signature_loaders(m->signature(),
1132 method_holder_loader,
1133 interface_loader,
1134 true, CHECK);
1135 if (failed_type_symbol != NULL) {
1136 const char* msg = "loader constraint violation in interface "
1137 "itable initialization: when resolving method \"%s\" the class"
1138 " loader (instance of %s) of the current class, %s, "
1139 "and the class loader (instance of %s) for interface "
1140 "%s have different Class objects for the type %s "
1141 "used in the signature";
1142 char* sig = target()->name_and_sig_as_C_string();
1143 const char* loader1 = SystemDictionary::loader_name(method_holder_loader());
1144 char* current = _klass->name()->as_C_string();
1145 const char* loader2 = SystemDictionary::loader_name(interface_loader());
1146 char* iface = InstanceKlass::cast(interf_h())->name()->as_C_string();
1147 char* failed_type_name = failed_type_symbol->as_C_string();
1148 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
1149 strlen(current) + strlen(loader2) + strlen(iface) +
1150 strlen(failed_type_name);
1151 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
1152 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2,
1153 iface, failed_type_name);
1154 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
1155 }
1156 }
1157 }
1158
1159 // ime may have moved during GC so recalculate address
1160 int ime_num = m->itable_index();
1161 assert(ime_num < ime_count, "oob");
1162 itableOffsetEntry::method_entry(_klass(), method_table_offset)[ime_num].initialize(target());
1163 if (TraceItables && Verbose) {
1164 ResourceMark rm(THREAD);
1165 if (target() != NULL) {
1166 char* sig = target()->name_and_sig_as_C_string();
1167 tty->print("interface: %s, ime_num: %d, target: %s, method_holder: %s ",
1168 interf_h()->internal_name(), ime_num, sig,
1169 target()->method_holder()->internal_name());
1170 tty->print("target_method flags: ");
1171 target()->access_flags().print_on(tty);
1172 if (target()->is_default_method()) {
1173 tty->print("default ");
1174 }
1175 tty->cr();
1176 }
1177 }
1178 }
1179 }
1180 }
1181
1182 // Update entry for specific Method*
1183 void klassItable::initialize_with_method(Method* m) {
1184 itableMethodEntry* ime = method_entry(0);
1185 for(int i = 0; i < _size_method_table; i++) {
1186 if (ime->method() == m) {
1187 ime->initialize(m);
1188 }
1189 ime++;
1190 }
1191 }
1192
1193 #if INCLUDE_JVMTI
1194 void klassItable::adjust_method_entries(Method** old_methods, Method** new_methods,
1195 int methods_length, bool * trace_name_printed) {
1196 // search the itable for uses of either obsolete or EMCP methods
1197 for (int j = 0; j < methods_length; j++) {
1198 Method* old_method = old_methods[j];
1199 Method* new_method = new_methods[j];
1200 itableMethodEntry* ime = method_entry(0);
1201
1202 // The itable can describe more than one interface and the same
1203 // method signature can be specified by more than one interface.
1204 // This means we have to do an exhaustive search to find all the
1205 // old_method references.
1206 for (int i = 0; i < _size_method_table; i++) {
1207 if (ime->method() == old_method) {
1208 ime->initialize(new_method);
1209
1210 if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
1211 if (!(*trace_name_printed)) {
1212 // RC_TRACE_MESG macro has an embedded ResourceMark
1213 RC_TRACE_MESG(("adjust: name=%s",
1214 old_method->method_holder()->external_name()));
1215 *trace_name_printed = true;
1216 }
1217 // RC_TRACE macro has an embedded ResourceMark
1218 RC_TRACE(0x00200000, ("itable method update: %s(%s)",
1219 new_method->name()->as_C_string(),
1220 new_method->signature()->as_C_string()));
1221 }
1222 // cannot 'break' here; see for-loop comment above.
1223 }
1224 ime++;
1225 }
1226 }
1227 }
1228
1229 // an itable should never contain old or obsolete methods
1230 bool klassItable::check_no_old_or_obsolete_entries() {
1231 itableMethodEntry* ime = method_entry(0);
1232 for (int i = 0; i < _size_method_table; i++) {
1233 Method* m = ime->method();
1234 if (m != NULL &&
1235 (NOT_PRODUCT(!m->is_valid() ||) m->is_old() || m->is_obsolete())) {
1236 return false;
1237 }
1238 ime++;
1239 }
1240 return true;
1241 }
1242
1243 void klassItable::dump_itable() {
1244 itableMethodEntry* ime = method_entry(0);
1245 tty->print_cr("itable dump --");
1246 for (int i = 0; i < _size_method_table; i++) {
1247 Method* m = ime->method();
1248 if (m != NULL) {
1249 tty->print(" (%5d) ", i);
1250 m->access_flags().print_on(tty);
1251 if (m->is_default_method()) {
1252 tty->print("default ");
1253 }
1254 tty->print(" -- ");
1255 m->print_name(tty);
1256 tty->cr();
1257 }
1258 ime++;
1259 }
1260 }
1261 #endif // INCLUDE_JVMTI
1262
1263
1264 // Setup
1265 class InterfaceVisiterClosure : public StackObj {
1266 public:
1267 virtual void doit(Klass* intf, int method_count) = 0;
1268 };
1269
1270 // Visit all interfaces with at least one itable method
1271 void visit_all_interfaces(Array<Klass*>* transitive_intf, InterfaceVisiterClosure *blk) {
1272 // Handle array argument
1273 for(int i = 0; i < transitive_intf->length(); i++) {
1274 Klass* intf = transitive_intf->at(i);
1275 assert(intf->is_interface(), "sanity check");
1276
1277 // Find no. of itable methods
1278 int method_count = 0;
1279 // method_count = klassItable::method_count_for_interface(intf);
1280 Array<Method*>* methods = InstanceKlass::cast(intf)->methods();
1281 if (methods->length() > 0) {
1282 for (int i = methods->length(); --i >= 0; ) {
1283 if (interface_method_needs_itable_index(methods->at(i))) {
1284 method_count++;
1285 }
1286 }
1287 }
1288
1289 // Only count interfaces with at least one method
1290 if (method_count > 0) {
1291 blk->doit(intf, method_count);
1292 }
1293 }
1294 }
1295
1296 class CountInterfacesClosure : public InterfaceVisiterClosure {
1297 private:
1298 int _nof_methods;
1299 int _nof_interfaces;
1300 public:
1301 CountInterfacesClosure() { _nof_methods = 0; _nof_interfaces = 0; }
1302
1303 int nof_methods() const { return _nof_methods; }
1304 int nof_interfaces() const { return _nof_interfaces; }
1305
1306 void doit(Klass* intf, int method_count) { _nof_methods += method_count; _nof_interfaces++; }
1307 };
1308
1309 class SetupItableClosure : public InterfaceVisiterClosure {
1310 private:
1311 itableOffsetEntry* _offset_entry;
1312 itableMethodEntry* _method_entry;
1313 address _klass_begin;
1314 public:
1315 SetupItableClosure(address klass_begin, itableOffsetEntry* offset_entry, itableMethodEntry* method_entry) {
1316 _klass_begin = klass_begin;
1317 _offset_entry = offset_entry;
1318 _method_entry = method_entry;
1319 }
1320
1321 itableMethodEntry* method_entry() const { return _method_entry; }
1322
1323 void doit(Klass* intf, int method_count) {
1324 int offset = ((address)_method_entry) - _klass_begin;
1325 _offset_entry->initialize(intf, offset);
1326 _offset_entry++;
1327 _method_entry += method_count;
1328 }
1329 };
1330
1331 int klassItable::compute_itable_size(Array<Klass*>* transitive_interfaces) {
1332 // Count no of interfaces and total number of interface methods
1333 CountInterfacesClosure cic;
1334 visit_all_interfaces(transitive_interfaces, &cic);
1335
1336 // There's alway an extra itable entry so we can null-terminate it.
1337 int itable_size = calc_itable_size(cic.nof_interfaces() + 1, cic.nof_methods());
1338
1339 // Statistics
1340 update_stats(itable_size * HeapWordSize);
1341
1342 return itable_size;
1343 }
1344
1345
1346 // Fill out offset table and interface klasses into the itable space
1347 void klassItable::setup_itable_offset_table(instanceKlassHandle klass) {
1348 if (klass->itable_length() == 0) return;
1349 assert(!klass->is_interface(), "Should have zero length itable");
1350
1351 // Count no of interfaces and total number of interface methods
1352 CountInterfacesClosure cic;
1353 visit_all_interfaces(klass->transitive_interfaces(), &cic);
1354 int nof_methods = cic.nof_methods();
1355 int nof_interfaces = cic.nof_interfaces();
1356
1357 // Add one extra entry so we can null-terminate the table
1358 nof_interfaces++;
1359
1360 assert(compute_itable_size(klass->transitive_interfaces()) ==
1361 calc_itable_size(nof_interfaces, nof_methods),
1362 "mismatch calculation of itable size");
1363
1364 // Fill-out offset table
1365 itableOffsetEntry* ioe = (itableOffsetEntry*)klass->start_of_itable();
1366 itableMethodEntry* ime = (itableMethodEntry*)(ioe + nof_interfaces);
1367 intptr_t* end = klass->end_of_itable();
1368 assert((oop*)(ime + nof_methods) <= (oop*)klass->start_of_nonstatic_oop_maps(), "wrong offset calculation (1)");
1369 assert((oop*)(end) == (oop*)(ime + nof_methods), "wrong offset calculation (2)");
1370
1371 // Visit all interfaces and initialize itable offset table
1372 SetupItableClosure sic((address)klass(), ioe, ime);
1373 visit_all_interfaces(klass->transitive_interfaces(), &sic);
1374
1375 #ifdef ASSERT
1376 ime = sic.method_entry();
1377 oop* v = (oop*) klass->end_of_itable();
1378 assert( (oop*)(ime) == v, "wrong offset calculation (2)");
1379 #endif
1380 }
1381
1382
1383 // inverse to itable_index
1384 Method* klassItable::method_for_itable_index(Klass* intf, int itable_index) {
1385 assert(InstanceKlass::cast(intf)->is_interface(), "sanity check");
1386 assert(intf->verify_itable_index(itable_index), "");
1387 Array<Method*>* methods = InstanceKlass::cast(intf)->methods();
1388
1389 if (itable_index < 0 || itable_index >= method_count_for_interface(intf))
1390 return NULL; // help caller defend against bad indices
1391
1392 int index = itable_index;
1393 Method* m = methods->at(index);
1394 int index2 = -1;
1395 while (!m->has_itable_index() ||
1396 (index2 = m->itable_index()) != itable_index) {
1397 assert(index2 < itable_index, "monotonic");
1398 if (++index == methods->length())
1399 return NULL;
1400 m = methods->at(index);
1401 }
1402 assert(m->itable_index() == itable_index, "correct inverse");
1403
1404 return m;
1405 }
1406
1407 void klassVtable::verify(outputStream* st, bool forced) {
1408 // make sure table is initialized
1409 if (!Universe::is_fully_initialized()) return;
1410 #ifndef PRODUCT
1411 // avoid redundant verifies
1412 if (!forced && _verify_count == Universe::verify_count()) return;
1413 _verify_count = Universe::verify_count();
1414 #endif
1415 oop* end_of_obj = (oop*)_klass() + _klass()->size();
1416 oop* end_of_vtable = (oop *)&table()[_length];
1417 if (end_of_vtable > end_of_obj) {
1418 fatal(err_msg("klass %s: klass object too short (vtable extends beyond "
1419 "end)", _klass->internal_name()));
1420 }
1421
1422 for (int i = 0; i < _length; i++) table()[i].verify(this, st);
1423 // verify consistency with superKlass vtable
1424 Klass* super = _klass->super();
1425 if (super != NULL) {
1426 InstanceKlass* sk = InstanceKlass::cast(super);
1427 klassVtable* vt = sk->vtable();
1428 for (int i = 0; i < vt->length(); i++) {
1429 verify_against(st, vt, i);
1430 }
1431 }
1432 }
1433
1434 void klassVtable::verify_against(outputStream* st, klassVtable* vt, int index) {
1435 vtableEntry* vte = &vt->table()[index];
1436 if (vte->method()->name() != table()[index].method()->name() ||
1437 vte->method()->signature() != table()[index].method()->signature()) {
1438 fatal("mismatched name/signature of vtable entries");
1439 }
1440 }
1441
1442 #ifndef PRODUCT
1443 void klassVtable::print() {
1444 ResourceMark rm;
1445 tty->print("klassVtable for klass %s (length %d):\n", _klass->internal_name(), length());
1446 for (int i = 0; i < length(); i++) {
1447 table()[i].print();
1448 tty->cr();
1449 }
1450 }
1451 #endif
1452
1453 void vtableEntry::verify(klassVtable* vt, outputStream* st) {
1454 NOT_PRODUCT(FlagSetting fs(IgnoreLockingAssertions, true));
1455 assert(method() != NULL, "must have set method");
1456 method()->verify();
1457 // we sub_type, because it could be a miranda method
1458 if (!vt->klass()->is_subtype_of(method()->method_holder())) {
1459 #ifndef PRODUCT
1460 print();
1461 #endif
1462 fatal(err_msg("vtableEntry " PTR_FORMAT ": method is from subclass", this));
1463 }
1464 }
1465
1466 #ifndef PRODUCT
1467
1468 void vtableEntry::print() {
1469 ResourceMark rm;
1470 tty->print("vtableEntry %s: ", method()->name()->as_C_string());
1471 if (Verbose) {
1472 tty->print("m %#lx ", (address)method());
1473 }
1474 }
1475
1476 class VtableStats : AllStatic {
1477 public:
1478 static int no_klasses; // # classes with vtables
1479 static int no_array_klasses; // # array classes
1480 static int no_instance_klasses; // # instanceKlasses
1481 static int sum_of_vtable_len; // total # of vtable entries
1482 static int sum_of_array_vtable_len; // total # of vtable entries in array klasses only
1483 static int fixed; // total fixed overhead in bytes
1484 static int filler; // overhead caused by filler bytes
1485 static int entries; // total bytes consumed by vtable entries
1486 static int array_entries; // total bytes consumed by array vtable entries
1487
1488 static void do_class(Klass* k) {
1489 Klass* kl = k;
1490 klassVtable* vt = kl->vtable();
1491 if (vt == NULL) return;
1492 no_klasses++;
1493 if (kl->oop_is_instance()) {
1494 no_instance_klasses++;
1495 kl->array_klasses_do(do_class);
1496 }
1497 if (kl->oop_is_array()) {
1498 no_array_klasses++;
1499 sum_of_array_vtable_len += vt->length();
1500 }
1501 sum_of_vtable_len += vt->length();
1502 }
1503
1504 static void compute() {
1505 SystemDictionary::classes_do(do_class);
1506 fixed = no_klasses * oopSize; // vtable length
1507 // filler size is a conservative approximation
1508 filler = oopSize * (no_klasses - no_instance_klasses) * (sizeof(InstanceKlass) - sizeof(ArrayKlass) - 1);
1509 entries = sizeof(vtableEntry) * sum_of_vtable_len;
1510 array_entries = sizeof(vtableEntry) * sum_of_array_vtable_len;
1511 }
1512 };
1513
1514 int VtableStats::no_klasses = 0;
1515 int VtableStats::no_array_klasses = 0;
1516 int VtableStats::no_instance_klasses = 0;
1517 int VtableStats::sum_of_vtable_len = 0;
1518 int VtableStats::sum_of_array_vtable_len = 0;
1519 int VtableStats::fixed = 0;
1520 int VtableStats::filler = 0;
1521 int VtableStats::entries = 0;
1522 int VtableStats::array_entries = 0;
1523
1524 void klassVtable::print_statistics() {
1525 ResourceMark rm;
1526 HandleMark hm;
1527 VtableStats::compute();
1528 tty->print_cr("vtable statistics:");
1529 tty->print_cr("%6d classes (%d instance, %d array)", VtableStats::no_klasses, VtableStats::no_instance_klasses, VtableStats::no_array_klasses);
1530 int total = VtableStats::fixed + VtableStats::filler + VtableStats::entries;
1531 tty->print_cr("%6d bytes fixed overhead (refs + vtable object header)", VtableStats::fixed);
1532 tty->print_cr("%6d bytes filler overhead", VtableStats::filler);
1533 tty->print_cr("%6d bytes for vtable entries (%d for arrays)", VtableStats::entries, VtableStats::array_entries);
1534 tty->print_cr("%6d bytes total", total);
1535 }
1536
1537 int klassItable::_total_classes; // Total no. of classes with itables
1538 long klassItable::_total_size; // Total no. of bytes used for itables
1539
1540 void klassItable::print_statistics() {
1541 tty->print_cr("itable statistics:");
1542 tty->print_cr("%6d classes with itables", _total_classes);
1543 tty->print_cr("%6d K uses for itables (average by class: %d bytes)", _total_size / K, _total_size / _total_classes);
1544 }
1545
1546 #endif // PRODUCT