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 "memory/gcLocker.hpp"
30 #include "memory/resourceArea.hpp"
31 #include "memory/universe.inline.hpp"
32 #include "oops/instanceKlass.hpp"
33 #include "oops/klassVtable.hpp"
34 #include "oops/method.hpp"
35 #include "oops/objArrayOop.hpp"
36 #include "oops/oop.inline.hpp"
37 #include "prims/jvmtiRedefineClassesTrace.hpp"
38 #include "runtime/arguments.hpp"
39 #include "runtime/handles.inline.hpp"
40 #include "utilities/copy.hpp"
41
42 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
43
44 inline InstanceKlass* klassVtable::ik() const {
45 Klass* k = _klass();
46 assert(k->oop_is_instance(), "not an InstanceKlass");
47 return (InstanceKlass*)k;
48 }
49
50
51 // this function computes the vtable size (including the size needed for miranda
52 // methods) and the number of miranda methods in this class.
53 // Note on Miranda methods: Let's say there is a class C that implements
54 // interface I, and none of C's superclasses implements I.
55 // Let's say there is an abstract method m in I that neither C
56 // nor any of its super classes implement (i.e there is no method of any access,
57 // with the same name and signature as m), then m is a Miranda method which is
58 // entered as a public abstract method in C's vtable. From then on it should
59 // treated as any other public method in C for method over-ride purposes.
60 void klassVtable::compute_vtable_size_and_num_mirandas(
61 int* vtable_length_ret, int* num_new_mirandas,
62 GrowableArray<Method*>* all_mirandas, Klass* super,
63 Array<Method*>* methods, AccessFlags class_flags,
64 Handle classloader, Symbol* classname, Array<Klass*>* local_interfaces,
65 TRAPS) {
66 No_Safepoint_Verifier nsv;
67
68 // set up default result values
69 int vtable_length = 0;
70
71 // start off with super's vtable length
72 InstanceKlass* sk = (InstanceKlass*)super;
73 vtable_length = super == NULL ? 0 : sk->vtable_length();
74
75 // go thru each method in the methods table to see if it needs a new entry
76 int len = methods->length();
77 for (int i = 0; i < len; i++) {
78 assert(methods->at(i)->is_method(), "must be a Method*");
79 methodHandle mh(THREAD, methods->at(i));
80
81 if (needs_new_vtable_entry(mh, super, classloader, classname, class_flags, THREAD)) {
82 vtable_length += vtableEntry::size(); // we need a new entry
83 }
84 }
85
86 GrowableArray<Method*> new_mirandas(20);
87 // compute the number of mirandas methods that must be added to the end
88 get_mirandas(&new_mirandas, all_mirandas, super, methods, NULL, local_interfaces);
89 *num_new_mirandas = new_mirandas.length();
90
91 // Interfaces do not need interface methods in their vtables
92 // This includes miranda methods and during later processing, default methods
93 if (!class_flags.is_interface()) {
94 vtable_length += *num_new_mirandas * vtableEntry::size();
95 }
96
97 if (Universe::is_bootstrapping() && vtable_length == 0) {
98 // array classes don't have their superclass set correctly during
99 // bootstrapping
100 vtable_length = Universe::base_vtable_size();
101 }
102
103 if (super == NULL && !Universe::is_bootstrapping() &&
104 vtable_length != Universe::base_vtable_size()) {
105 // Someone is attempting to redefine java.lang.Object incorrectly. The
106 // only way this should happen is from
107 // SystemDictionary::resolve_from_stream(), which will detect this later
108 // and throw a security exception. So don't assert here to let
109 // the exception occur.
110 vtable_length = Universe::base_vtable_size();
111 }
112 assert(super != NULL || vtable_length == Universe::base_vtable_size(),
113 "bad vtable size for class Object");
114 assert(vtable_length % vtableEntry::size() == 0, "bad vtable length");
115 assert(vtable_length >= Universe::base_vtable_size(), "vtable too small");
116
117 *vtable_length_ret = vtable_length;
118 }
119
120 int klassVtable::index_of(Method* m, int len) const {
121 assert(m->has_vtable_index(), "do not ask this of non-vtable methods");
122 return m->vtable_index();
123 }
124
125 // Copy super class's vtable to the first part (prefix) of this class's vtable,
126 // and return the number of entries copied. Expects that 'super' is the Java
127 // super class (arrays can have "array" super classes that must be skipped).
128 int klassVtable::initialize_from_super(KlassHandle super) {
129 if (super.is_null()) {
130 return 0;
131 } else {
132 // copy methods from superKlass
133 // can't inherit from array class, so must be InstanceKlass
134 assert(super->oop_is_instance(), "must be instance klass");
135 InstanceKlass* sk = (InstanceKlass*)super();
136 klassVtable* superVtable = sk->vtable();
137 assert(superVtable->length() <= _length, "vtable too short");
138 #ifdef ASSERT
139 superVtable->verify(tty, true);
140 #endif
141 superVtable->copy_vtable_to(table());
142 #ifndef PRODUCT
143 if (PrintVtables && Verbose) {
144 ResourceMark rm;
145 tty->print_cr("copy vtable from %s to %s size %d", sk->internal_name(), klass()->internal_name(), _length);
146 }
147 #endif
148 return superVtable->length();
149 }
150 }
151
152 //
153 // Revised lookup semantics introduced 1.3 (Kestrel beta)
154 void klassVtable::initialize_vtable(bool checkconstraints, TRAPS) {
155
156 // Note: Arrays can have intermediate array supers. Use java_super to skip them.
157 KlassHandle super (THREAD, klass()->java_super());
158 int nofNewEntries = 0;
159
160 if (PrintVtables && !klass()->oop_is_array()) {
161 ResourceMark rm(THREAD);
162 tty->print_cr("Initializing: %s", _klass->name()->as_C_string());
163 }
164
165 #ifdef ASSERT
166 oop* end_of_obj = (oop*)_klass() + _klass()->size();
167 oop* end_of_vtable = (oop*)&table()[_length];
168 assert(end_of_vtable <= end_of_obj, "vtable extends beyond end");
169 #endif
170
171 if (Universe::is_bootstrapping()) {
172 // just clear everything
173 for (int i = 0; i < _length; i++) table()[i].clear();
174 return;
175 }
176
177 int super_vtable_len = initialize_from_super(super);
178 if (klass()->oop_is_array()) {
179 assert(super_vtable_len == _length, "arrays shouldn't introduce new methods");
180 } else {
181 assert(_klass->oop_is_instance(), "must be InstanceKlass");
182
183 Array<Method*>* methods = ik()->methods();
184 int len = methods->length();
185 int initialized = super_vtable_len;
186
187 // Check each of this class's methods against super;
188 // if override, replace in copy of super vtable, otherwise append to end
189 for (int i = 0; i < len; i++) {
190 // update_inherited_vtable can stop for gc - ensure using handles
191 HandleMark hm(THREAD);
192 assert(methods->at(i)->is_method(), "must be a Method*");
193 methodHandle mh(THREAD, methods->at(i));
194
195 bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, -1, checkconstraints, CHECK);
196
197 if (needs_new_entry) {
198 put_method_at(mh(), initialized);
199 mh()->set_vtable_index(initialized); // set primary vtable index
200 initialized++;
201 }
202 }
203
204 // update vtable with default_methods
205 Array<Method*>* default_methods = ik()->default_methods();
206 if (default_methods != NULL) {
207 len = default_methods->length();
208 if (len > 0) {
209 Array<int>* def_vtable_indices = NULL;
210 if ((def_vtable_indices = ik()->default_vtable_indices()) == NULL) {
211 def_vtable_indices = ik()->create_new_default_vtable_indices(len, CHECK);
212 } else {
213 assert(def_vtable_indices->length() == len, "reinit vtable len?");
214 }
215 for (int i = 0; i < len; i++) {
216 HandleMark hm(THREAD);
217 assert(default_methods->at(i)->is_method(), "must be a Method*");
218 methodHandle mh(THREAD, default_methods->at(i));
219
220 bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, i, checkconstraints, CHECK);
221
222 // needs new entry
223 if (needs_new_entry) {
224 put_method_at(mh(), initialized);
225 def_vtable_indices->at_put(i, initialized); //set vtable index
226 initialized++;
227 }
228 }
229 }
230 }
231
232 // add miranda methods; it will also return the updated initialized
233 // Interfaces do not need interface methods in their vtables
234 // This includes miranda methods and during later processing, default methods
235 if (!ik()->is_interface()) {
236 initialized = fill_in_mirandas(initialized);
237 }
238
239 // In class hierarchies where the accessibility is not increasing (i.e., going from private ->
240 // package_private -> public/protected), the vtable might actually be smaller than our initial
241 // calculation.
242 assert(initialized <= _length, "vtable initialization failed");
243 for(;initialized < _length; initialized++) {
244 put_method_at(NULL, initialized);
245 }
246 NOT_PRODUCT(verify(tty, true));
247 }
248 }
249
250 // Called for cases where a method does not override its superclass' vtable entry
251 // For bytecodes not produced by javac together it is possible that a method does not override
252 // the superclass's method, but might indirectly override a super-super class's vtable entry
253 // If none found, return a null superk, else return the superk of the method this does override
254 // For public and protected methods: if they override a superclass, they will
255 // also be overridden themselves appropriately.
256 // Private methods do not override and are not overridden.
257 // Package Private methods are trickier:
258 // e.g. P1.A, pub m
259 // P2.B extends A, package private m
260 // P1.C extends B, public m
261 // P1.C.m needs to override P1.A.m and can not override P2.B.m
262 // Therefore: all package private methods need their own vtable entries for
263 // them to be the root of an inheritance overriding decision
264 // Package private methods may also override other vtable entries
265 InstanceKlass* klassVtable::find_transitive_override(InstanceKlass* initialsuper, methodHandle target_method,
266 int vtable_index, Handle target_loader, Symbol* target_classname, Thread * THREAD) {
267 InstanceKlass* superk = initialsuper;
268 while (superk != NULL && superk->super() != NULL) {
269 InstanceKlass* supersuperklass = InstanceKlass::cast(superk->super());
270 klassVtable* ssVtable = supersuperklass->vtable();
271 if (vtable_index < ssVtable->length()) {
272 Method* super_method = ssVtable->method_at(vtable_index);
273 #ifndef PRODUCT
274 Symbol* name= target_method()->name();
275 Symbol* signature = target_method()->signature();
276 assert(super_method->name() == name && super_method->signature() == signature, "vtable entry name/sig mismatch");
277 #endif
278 if (supersuperklass->is_override(super_method, target_loader, target_classname, THREAD)) {
279 #ifndef PRODUCT
280 if (PrintVtables && Verbose) {
281 ResourceMark rm(THREAD);
282 char* sig = target_method()->name_and_sig_as_C_string();
283 tty->print("transitive overriding superclass %s with %s::%s index %d, original flags: ",
284 supersuperklass->internal_name(),
285 _klass->internal_name(), sig, vtable_index);
286 super_method->access_flags().print_on(tty);
287 if (super_method->is_default_method()) {
288 tty->print("default ");
289 }
290 tty->print("overriders flags: ");
291 target_method->access_flags().print_on(tty);
292 if (target_method->is_default_method()) {
293 tty->print("default ");
294 }
295 }
296 #endif /*PRODUCT*/
297 break; // return found superk
298 }
299 } else {
300 // super class has no vtable entry here, stop transitive search
301 superk = (InstanceKlass*)NULL;
302 break;
303 }
304 // if no override found yet, continue to search up
305 superk = InstanceKlass::cast(superk->super());
306 }
307
308 return superk;
309 }
310
311 // Update child's copy of super vtable for overrides
312 // OR return true if a new vtable entry is required.
313 // Only called for InstanceKlass's, i.e. not for arrays
314 // If that changed, could not use _klass as handle for klass
315 bool klassVtable::update_inherited_vtable(InstanceKlass* klass, methodHandle target_method,
316 int super_vtable_len, int default_index,
317 bool checkconstraints, TRAPS) {
318 ResourceMark rm;
319 bool allocate_new = true;
320 assert(klass->oop_is_instance(), "must be InstanceKlass");
321
322 Array<int>* def_vtable_indices = NULL;
323 bool is_default = false;
324 // default methods are concrete methods in superinterfaces which are added to the vtable
325 // with their real method_holder
326 // Since vtable and itable indices share the same storage, don't touch
327 // the default method's real vtable/itable index
328 // default_vtable_indices stores the vtable value relative to this inheritor
329 if (default_index >= 0 ) {
330 is_default = true;
331 def_vtable_indices = klass->default_vtable_indices();
332 assert(def_vtable_indices != NULL, "def vtable alloc?");
333 assert(default_index <= def_vtable_indices->length(), "def vtable len?");
334 } else {
335 assert(klass == target_method()->method_holder(), "caller resp.");
336 // Initialize the method's vtable index to "nonvirtual".
337 // If we allocate a vtable entry, we will update it to a non-negative number.
338 target_method()->set_vtable_index(Method::nonvirtual_vtable_index);
339 }
340
341 // Static and <init> methods are never in
342 if (target_method()->is_static() || target_method()->name() == vmSymbols::object_initializer_name()) {
343 return false;
344 }
345
346 if (target_method->is_final_method(klass->access_flags())) {
347 // a final method never needs a new entry; final methods can be statically
348 // resolved and they have to be present in the vtable only if they override
349 // a super's method, in which case they re-use its entry
350 allocate_new = false;
351 } else if (klass->is_interface()) {
352 allocate_new = false; // see note below in needs_new_vtable_entry
353 // An interface never allocates new vtable slots, only inherits old ones.
354 // This method will either be assigned its own itable index later,
355 // or be assigned an inherited vtable index in the loop below.
356 // default methods inherited by classes store their vtable indices
357 // in the inheritor's default_vtable_indices
358 // default methods inherited by interfaces may already have a
359 // valid itable index, if so, don't change it
360 // overpass methods in an interface will be assigned an itable index later
361 // by an inheriting class
362 if (!is_default || !target_method()->has_itable_index()) {
363 target_method()->set_vtable_index(Method::pending_itable_index);
364 }
365 }
366
367 // we need a new entry if there is no superclass
368 if (klass->super() == NULL) {
369 return allocate_new;
370 }
371
372 // private methods in classes always have a new entry in the vtable
373 // specification interpretation since classic has
374 // private methods not overriding
375 // JDK8 adds private methods in interfaces which require invokespecial
376 if (target_method()->is_private()) {
377 return allocate_new;
378 }
379
380 // search through the vtable and update overridden entries
381 // Since check_signature_loaders acquires SystemDictionary_lock
382 // which can block for gc, once we are in this loop, use handles
383 // For classfiles built with >= jdk7, we now look for transitive overrides
384
385 Symbol* name = target_method()->name();
386 Symbol* signature = target_method()->signature();
387
388 KlassHandle target_klass(THREAD, target_method()->method_holder());
389 if (target_klass == NULL) {
390 target_klass = _klass;
391 }
392
393 Handle target_loader(THREAD, target_klass->class_loader());
394
395 Symbol* target_classname = target_klass->name();
396 for(int i = 0; i < super_vtable_len; i++) {
397 Method* super_method = method_at(i);
398 // Check if method name matches
399 if (super_method->name() == name && super_method->signature() == signature) {
400
401 // get super_klass for method_holder for the found method
402 InstanceKlass* super_klass = super_method->method_holder();
403
404 if (is_default
405 || ((super_klass->is_override(super_method, target_loader, target_classname, THREAD))
406 || ((klass->major_version() >= VTABLE_TRANSITIVE_OVERRIDE_VERSION)
407 && ((super_klass = find_transitive_override(super_klass,
408 target_method, i, target_loader,
409 target_classname, THREAD))
410 != (InstanceKlass*)NULL))))
411 {
412 // Package private methods always need a new entry to root their own
413 // overriding. They may also override other methods.
414 if (!target_method()->is_package_private()) {
415 allocate_new = false;
416 }
417
418 if (checkconstraints) {
419 // Override vtable entry if passes loader constraint check
420 // if loader constraint checking requested
421 // No need to visit his super, since he and his super
422 // have already made any needed loader constraints.
423 // Since loader constraints are transitive, it is enough
424 // to link to the first super, and we get all the others.
425 Handle super_loader(THREAD, super_klass->class_loader());
426
427 if (target_loader() != super_loader()) {
428 ResourceMark rm(THREAD);
429 Symbol* failed_type_symbol =
430 SystemDictionary::check_signature_loaders(signature, target_loader,
431 super_loader, true,
432 CHECK_(false));
433 if (failed_type_symbol != NULL) {
434 const char* msg = "loader constraint violation: when resolving "
435 "overridden method \"%s\" the class loader (instance"
436 " of %s) of the current class, %s, and its superclass loader "
437 "(instance of %s), have different Class objects for the type "
438 "%s used in the signature";
439 char* sig = target_method()->name_and_sig_as_C_string();
440 const char* loader1 = SystemDictionary::loader_name(target_loader());
441 char* current = target_klass->name()->as_C_string();
442 const char* loader2 = SystemDictionary::loader_name(super_loader());
443 char* failed_type_name = failed_type_symbol->as_C_string();
444 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
445 strlen(current) + strlen(loader2) + strlen(failed_type_name);
446 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
447 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2,
448 failed_type_name);
449 THROW_MSG_(vmSymbols::java_lang_LinkageError(), buf, false);
450 }
451 }
452 }
453
454 put_method_at(target_method(), i);
455 if (!is_default) {
456 target_method()->set_vtable_index(i);
457 } else {
458 if (def_vtable_indices != NULL) {
459 def_vtable_indices->at_put(default_index, i);
460 }
461 assert(super_method->is_default_method() || super_method->is_overpass()
462 || super_method->is_abstract(), "default override error");
463 }
464
465
466 #ifndef PRODUCT
467 if (PrintVtables && Verbose) {
468 ResourceMark rm(THREAD);
469 char* sig = target_method()->name_and_sig_as_C_string();
470 tty->print("overriding with %s::%s index %d, original flags: ",
471 target_klass->internal_name(), sig, i);
472 super_method->access_flags().print_on(tty);
473 if (super_method->is_default_method()) {
474 tty->print("default ");
475 }
476 if (super_method->is_overpass()) {
477 tty->print("overpass");
478 }
479 tty->print("overriders flags: ");
480 target_method->access_flags().print_on(tty);
481 if (target_method->is_default_method()) {
482 tty->print("default ");
483 }
484 if (target_method->is_overpass()) {
485 tty->print("overpass");
486 }
487 tty->cr();
488 }
489 #endif /*PRODUCT*/
490 } else {
491 // allocate_new = true; default. We might override one entry,
492 // but not override another. Once we override one, not need new
493 #ifndef PRODUCT
494 if (PrintVtables && Verbose) {
495 ResourceMark rm(THREAD);
496 char* sig = target_method()->name_and_sig_as_C_string();
497 tty->print("NOT overriding with %s::%s index %d, original flags: ",
498 target_klass->internal_name(), sig,i);
499 super_method->access_flags().print_on(tty);
500 if (super_method->is_default_method()) {
501 tty->print("default ");
502 }
503 if (super_method->is_overpass()) {
504 tty->print("overpass");
505 }
506 tty->print("overriders flags: ");
507 target_method->access_flags().print_on(tty);
508 if (target_method->is_default_method()) {
509 tty->print("default ");
510 }
511 if (target_method->is_overpass()) {
512 tty->print("overpass");
513 }
514 tty->cr();
515 }
516 #endif /*PRODUCT*/
517 }
518 }
519 }
520 return allocate_new;
521 }
522
523 void klassVtable::put_method_at(Method* m, int index) {
524 #ifndef PRODUCT
525 if (PrintVtables && Verbose) {
526 ResourceMark rm;
527 const char* sig = (m != NULL) ? m->name_and_sig_as_C_string() : "<NULL>";
528 tty->print("adding %s at index %d, flags: ", sig, index);
529 if (m != NULL) {
530 m->access_flags().print_on(tty);
531 if (m->is_default_method()) {
532 tty->print("default ");
533 }
534 if (m->is_overpass()) {
535 tty->print("overpass");
536 }
537 }
538 tty->cr();
539 }
540 #endif
541 table()[index].set(m);
542 }
543
544 // Find out if a method "m" with superclass "super", loader "classloader" and
545 // name "classname" needs a new vtable entry. Let P be a class package defined
546 // by "classloader" and "classname".
547 // NOTE: The logic used here is very similar to the one used for computing
548 // the vtables indices for a method. We cannot directly use that function because,
549 // we allocate the InstanceKlass at load time, and that requires that the
550 // superclass has been loaded.
551 // However, the vtable entries are filled in at link time, and therefore
552 // the superclass' vtable may not yet have been filled in.
553 bool klassVtable::needs_new_vtable_entry(methodHandle target_method,
554 Klass* super,
555 Handle classloader,
556 Symbol* classname,
557 AccessFlags class_flags,
558 TRAPS) {
559 if (class_flags.is_interface()) {
560 // Interfaces do not use vtables, except for java.lang.Object methods,
561 // so there is no point to assigning
562 // a vtable index to any of their local methods. If we refrain from doing this,
563 // we can use Method::_vtable_index to hold the itable index
564 return false;
565 }
566
567 if (target_method->is_final_method(class_flags) ||
568 // a final method never needs a new entry; final methods can be statically
569 // resolved and they have to be present in the vtable only if they override
570 // a super's method, in which case they re-use its entry
571 (target_method()->is_static()) ||
572 // static methods don't need to be in vtable
573 (target_method()->name() == vmSymbols::object_initializer_name())
574 // <init> is never called dynamically-bound
575 ) {
576 return false;
577 }
578
579 // Concrete interface methods do not need new entries, they override
580 // abstract method entries using default inheritance rules
581 if (target_method()->method_holder() != NULL &&
582 target_method()->method_holder()->is_interface() &&
583 !target_method()->is_abstract() ) {
584 return false;
585 }
586
587 // we need a new entry if there is no superclass
588 if (super == NULL) {
589 return true;
590 }
591
592 // private methods in classes always have a new entry in the vtable
593 // specification interpretation since classic has
594 // private methods not overriding
595 // JDK8 adds private methods in interfaces which require invokespecial
596 if (target_method()->is_private()) {
597 return true;
598 }
599
600 // Package private methods always need a new entry to root their own
601 // overriding. This allows transitive overriding to work.
602 if (target_method()->is_package_private()) {
603 return true;
604 }
605
606 // search through the super class hierarchy to see if we need
607 // a new entry
608 ResourceMark rm;
609 Symbol* name = target_method()->name();
610 Symbol* signature = target_method()->signature();
611 Klass* k = super;
612 Method* super_method = NULL;
613 InstanceKlass *holder = NULL;
614 Method* recheck_method = NULL;
615 while (k != NULL) {
616 // lookup through the hierarchy for a method with matching name and sign.
617 super_method = InstanceKlass::cast(k)->lookup_method(name, signature);
618 if (super_method == NULL) {
619 break; // we still have to search for a matching miranda method
620 }
621 // get the class holding the matching method
622 // make sure you use that class for is_override
623 InstanceKlass* superk = super_method->method_holder();
624 // we want only instance method matches
625 // pretend private methods are not in the super vtable
626 // since we do override around them: e.g. a.m pub/b.m private/c.m pub,
627 // ignore private, c.m pub does override a.m pub
628 // For classes that were not javac'd together, we also do transitive overriding around
629 // methods that have less accessibility
630 if ((!super_method->is_static()) &&
631 (!super_method->is_private())) {
632 if (superk->is_override(super_method, classloader, classname, THREAD)) {
633 return false;
634 // else keep looking for transitive overrides
635 }
636 }
637
638 // Start with lookup result and continue to search up
639 k = superk->super(); // haven't found an override match yet; continue to look
640 }
641
642 // if the target method is public or protected it may have a matching
643 // miranda method in the super, whose entry it should re-use.
644 // Actually, to handle cases that javac would not generate, we need
645 // this check for all access permissions.
646 InstanceKlass *sk = InstanceKlass::cast(super);
647 if (sk->has_miranda_methods()) {
648 if (sk->lookup_method_in_all_interfaces(name, signature, Klass::normal) != NULL) {
649 return false; // found a matching miranda; we do not need a new entry
650 }
651 }
652 return true; // found no match; we need a new entry
653 }
654
655 // Support for miranda methods
656
657 // get the vtable index of a miranda method with matching "name" and "signature"
658 int klassVtable::index_of_miranda(Symbol* name, Symbol* signature) {
659 // search from the bottom, might be faster
660 for (int i = (length() - 1); i >= 0; i--) {
661 Method* m = table()[i].method();
662 if (is_miranda_entry_at(i) &&
663 m->name() == name && m->signature() == signature) {
664 return i;
665 }
666 }
667 return Method::invalid_vtable_index;
668 }
669
670 // check if an entry at an index is miranda
671 // requires that method m at entry be declared ("held") by an interface.
672 bool klassVtable::is_miranda_entry_at(int i) {
673 Method* m = method_at(i);
674 Klass* method_holder = m->method_holder();
675 InstanceKlass *mhk = InstanceKlass::cast(method_holder);
676
677 // miranda methods are public abstract instance interface methods in a class's vtable
678 if (mhk->is_interface()) {
679 assert(m->is_public(), "should be public");
680 assert(ik()->implements_interface(method_holder) , "this class should implement the interface");
681 // the search could find a miranda or a default method
682 if (is_miranda(m, ik()->methods(), ik()->default_methods(), ik()->super())) {
683 return true;
684 }
685 }
686 return false;
687 }
688
689 // check if a method is a miranda method, given a class's methods table,
690 // its default_method table and its super
691 // Miranda methods are calculated twice:
692 // first: before vtable size calculation: including abstract and default
693 // This is seen by default method creation
694 // Second: recalculated during vtable initialization: only abstract
695 // This is seen by link resolution and selection.
696 // "miranda" means not static, not defined by this class.
697 // private methods in interfaces do not belong in the miranda list.
698 // the caller must make sure that the method belongs to an interface implemented by the class
699 // Miranda methods only include public interface instance methods
700 // Not private methods, not static methods, not default == concrete abstract
701 // Miranda methods also do not include overpass methods in interfaces
702 bool klassVtable::is_miranda(Method* m, Array<Method*>* class_methods,
703 Array<Method*>* default_methods, Klass* super) {
704 if (m->is_static() || m->is_private() || m->is_overpass()) {
705 return false;
706 }
707 Symbol* name = m->name();
708 Symbol* signature = m->signature();
709
710 if (InstanceKlass::find_instance_method(class_methods, name, signature) == NULL) {
711 // did not find it in the method table of the current class
712 if ((default_methods == NULL) ||
713 InstanceKlass::find_method(default_methods, name, signature) == NULL) {
714 if (super == NULL) {
715 // super doesn't exist
716 return true;
717 }
718
719 Method* mo = InstanceKlass::cast(super)->lookup_method(name, signature);
720 while (mo != NULL && mo->access_flags().is_static()
721 && mo->method_holder() != NULL
722 && mo->method_holder()->super() != NULL)
723 {
724 mo = mo->method_holder()->super()->uncached_lookup_method(name, signature, Klass::normal);
725 }
726 if (mo == NULL || mo->access_flags().is_private() ) {
727 // super class hierarchy does not implement it or protection is different
728 return true;
729 }
730 }
731 }
732
733 return false;
734 }
735
736 // Scans current_interface_methods for miranda methods that do not
737 // already appear in new_mirandas, or default methods, and are also not defined-and-non-private
738 // in super (superclass). These mirandas are added to all_mirandas if it is
739 // not null; in addition, those that are not duplicates of miranda methods
740 // inherited by super from its interfaces are added to new_mirandas.
741 // Thus, new_mirandas will be the set of mirandas that this class introduces,
742 // all_mirandas will be the set of all mirandas applicable to this class
743 // including all defined in superclasses.
744 void klassVtable::add_new_mirandas_to_lists(
745 GrowableArray<Method*>* new_mirandas, GrowableArray<Method*>* all_mirandas,
746 Array<Method*>* current_interface_methods, Array<Method*>* class_methods,
747 Array<Method*>* default_methods, Klass* super) {
748
749 // iterate thru the current interface's method to see if it a miranda
750 int num_methods = current_interface_methods->length();
751 for (int i = 0; i < num_methods; i++) {
752 Method* im = current_interface_methods->at(i);
753 bool is_duplicate = false;
754 int num_of_current_mirandas = new_mirandas->length();
755 // check for duplicate mirandas in different interfaces we implement
756 for (int j = 0; j < num_of_current_mirandas; j++) {
757 Method* miranda = new_mirandas->at(j);
758 if ((im->name() == miranda->name()) &&
759 (im->signature() == miranda->signature())) {
760 is_duplicate = true;
761 break;
762 }
763 }
764
765 if (!is_duplicate) { // we don't want duplicate miranda entries in the vtable
766 if (is_miranda(im, class_methods, default_methods, super)) { // is it a miranda at all?
767 InstanceKlass *sk = InstanceKlass::cast(super);
768 // check if it is a duplicate of a super's miranda
769 if (sk->lookup_method_in_all_interfaces(im->name(), im->signature(), Klass::normal) == NULL) {
770 new_mirandas->append(im);
771 }
772 if (all_mirandas != NULL) {
773 all_mirandas->append(im);
774 }
775 }
776 }
777 }
778 }
779
780 void klassVtable::get_mirandas(GrowableArray<Method*>* new_mirandas,
781 GrowableArray<Method*>* all_mirandas,
782 Klass* super, Array<Method*>* class_methods,
783 Array<Method*>* default_methods,
784 Array<Klass*>* local_interfaces) {
785 assert((new_mirandas->length() == 0) , "current mirandas must be 0");
786
787 // iterate thru the local interfaces looking for a miranda
788 int num_local_ifs = local_interfaces->length();
789 for (int i = 0; i < num_local_ifs; i++) {
790 InstanceKlass *ik = InstanceKlass::cast(local_interfaces->at(i));
791 add_new_mirandas_to_lists(new_mirandas, all_mirandas,
792 ik->methods(), class_methods,
793 default_methods, super);
794 // iterate thru each local's super interfaces
795 Array<Klass*>* super_ifs = ik->transitive_interfaces();
796 int num_super_ifs = super_ifs->length();
797 for (int j = 0; j < num_super_ifs; j++) {
798 InstanceKlass *sik = InstanceKlass::cast(super_ifs->at(j));
799 add_new_mirandas_to_lists(new_mirandas, all_mirandas,
800 sik->methods(), class_methods,
801 default_methods, super);
802 }
803 }
804 }
805
806 // Discover miranda methods ("miranda" = "interface abstract, no binding"),
807 // and append them into the vtable starting at index initialized,
808 // return the new value of initialized.
809 // Miranda methods use vtable entries, but do not get assigned a vtable_index
810 // The vtable_index is discovered by searching from the end of the vtable
811 int klassVtable::fill_in_mirandas(int initialized) {
812 GrowableArray<Method*> mirandas(20);
813 get_mirandas(&mirandas, NULL, ik()->super(), ik()->methods(),
814 ik()->default_methods(), ik()->local_interfaces());
815 for (int i = 0; i < mirandas.length(); i++) {
816 if (PrintVtables && Verbose) {
817 Method* meth = mirandas.at(i);
818 ResourceMark rm(Thread::current());
819 if (meth != NULL) {
820 char* sig = meth->name_and_sig_as_C_string();
821 tty->print("fill in mirandas with %s index %d, flags: ",
822 sig, initialized);
823 meth->access_flags().print_on(tty);
824 if (meth->is_default_method()) {
825 tty->print("default ");
826 }
827 tty->cr();
828 }
829 }
830 put_method_at(mirandas.at(i), initialized);
831 ++initialized;
832 }
833 return initialized;
834 }
835
836 // Copy this class's vtable to the vtable beginning at start.
837 // Used to copy superclass vtable to prefix of subclass's vtable.
838 void klassVtable::copy_vtable_to(vtableEntry* start) {
839 Copy::disjoint_words((HeapWord*)table(), (HeapWord*)start, _length * vtableEntry::size());
840 }
841
842 #if INCLUDE_JVMTI
843 bool klassVtable::adjust_default_method(int vtable_index, Method* old_method, Method* new_method) {
844 // If old_method is default, find this vtable index in default_vtable_indices
845 // and replace that method in the _default_methods list
846 bool updated = false;
847
848 Array<Method*>* default_methods = ik()->default_methods();
849 if (default_methods != NULL) {
850 int len = default_methods->length();
851 for (int idx = 0; idx < len; idx++) {
852 if (vtable_index == ik()->default_vtable_indices()->at(idx)) {
853 if (default_methods->at(idx) == old_method) {
854 default_methods->at_put(idx, new_method);
855 updated = true;
856 }
857 break;
858 }
859 }
860 }
861 return updated;
862 }
863 void klassVtable::adjust_method_entries(Method** old_methods, Method** new_methods,
864 int methods_length, bool * trace_name_printed) {
865 // search the vtable for uses of either obsolete or EMCP methods
866 for (int j = 0; j < methods_length; j++) {
867 Method* old_method = old_methods[j];
868 Method* new_method = new_methods[j];
869
870 // In the vast majority of cases we could get the vtable index
871 // by using: old_method->vtable_index()
872 // However, there are rare cases, eg. sun.awt.X11.XDecoratedPeer.getX()
873 // in sun.awt.X11.XFramePeer where methods occur more than once in the
874 // vtable, so, alas, we must do an exhaustive search.
875 for (int index = 0; index < length(); index++) {
876 if (unchecked_method_at(index) == old_method) {
877 put_method_at(new_method, index);
878 // For default methods, need to update the _default_methods array
879 // which can only have one method entry for a given signature
880 bool updated_default = false;
881 if (old_method->is_default_method()) {
882 updated_default = adjust_default_method(index, old_method, new_method);
883 }
884
885 if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
886 if (!(*trace_name_printed)) {
887 // RC_TRACE_MESG macro has an embedded ResourceMark
888 RC_TRACE_MESG(("adjust: klassname=%s for methods from name=%s",
889 klass()->external_name(),
890 old_method->method_holder()->external_name()));
891 *trace_name_printed = true;
892 }
893 // RC_TRACE macro has an embedded ResourceMark
894 RC_TRACE(0x00100000, ("vtable method update: %s(%s), updated default = %s",
895 new_method->name()->as_C_string(),
896 new_method->signature()->as_C_string(),
897 updated_default ? "true" : "false"));
898 }
899 // cannot 'break' here; see for-loop comment above.
900 }
901 }
902 }
903 }
904
905 // a vtable should never contain old or obsolete methods
906 bool klassVtable::check_no_old_or_obsolete_entries() {
907 for (int i = 0; i < length(); i++) {
908 Method* m = unchecked_method_at(i);
909 if (m != NULL &&
910 (NOT_PRODUCT(!m->is_valid() ||) m->is_old() || m->is_obsolete())) {
911 return false;
912 }
913 }
914 return true;
915 }
916
917 void klassVtable::dump_vtable() {
918 tty->print_cr("vtable dump --");
919 for (int i = 0; i < length(); i++) {
920 Method* m = unchecked_method_at(i);
921 if (m != NULL) {
922 tty->print(" (%5d) ", i);
923 m->access_flags().print_on(tty);
924 if (m->is_default_method()) {
925 tty->print("default ");
926 }
927 if (m->is_overpass()) {
928 tty->print("overpass");
929 }
930 tty->print(" -- ");
931 m->print_name(tty);
932 tty->cr();
933 }
934 }
935 }
936 #endif // INCLUDE_JVMTI
937
938 // CDS/RedefineClasses support - clear vtables so they can be reinitialized
939 void klassVtable::clear_vtable() {
940 for (int i = 0; i < _length; i++) table()[i].clear();
941 }
942
943 bool klassVtable::is_initialized() {
944 return _length == 0 || table()[0].method() != NULL;
945 }
946
947 //-----------------------------------------------------------------------------------------
948 // Itable code
949
950 // Initialize a itableMethodEntry
951 void itableMethodEntry::initialize(Method* m) {
952 if (m == NULL) return;
953
954 _method = m;
955 }
956
957 klassItable::klassItable(instanceKlassHandle klass) {
958 _klass = klass;
959
960 if (klass->itable_length() > 0) {
961 itableOffsetEntry* offset_entry = (itableOffsetEntry*)klass->start_of_itable();
962 if (offset_entry != NULL && offset_entry->interface_klass() != NULL) { // Check that itable is initialized
963 // First offset entry points to the first method_entry
964 intptr_t* method_entry = (intptr_t *)(((address)klass()) + offset_entry->offset());
965 intptr_t* end = klass->end_of_itable();
966
967 _table_offset = (intptr_t*)offset_entry - (intptr_t*)klass();
968 _size_offset_table = (method_entry - ((intptr_t*)offset_entry)) / itableOffsetEntry::size();
969 _size_method_table = (end - method_entry) / itableMethodEntry::size();
970 assert(_table_offset >= 0 && _size_offset_table >= 0 && _size_method_table >= 0, "wrong computation");
971 return;
972 }
973 }
974
975 // The length of the itable was either zero, or it has not yet been initialized.
976 _table_offset = 0;
977 _size_offset_table = 0;
978 _size_method_table = 0;
979 }
980
981 static int initialize_count = 0;
982
983 // Initialization
984 void klassItable::initialize_itable(bool checkconstraints, TRAPS) {
985 if (_klass->is_interface()) {
986 // This needs to go after vtable indices are assigned but
987 // before implementors need to know the number of itable indices.
988 assign_itable_indices_for_interface(_klass());
989 }
990
991 // Cannot be setup doing bootstrapping, interfaces don't have
992 // itables, and klass with only ones entry have empty itables
993 if (Universe::is_bootstrapping() ||
994 _klass->is_interface() ||
995 _klass->itable_length() == itableOffsetEntry::size()) return;
996
997 // There's alway an extra itable entry so we can null-terminate it.
998 guarantee(size_offset_table() >= 1, "too small");
999 int num_interfaces = size_offset_table() - 1;
1000 if (num_interfaces > 0) {
1001 if (TraceItables) tty->print_cr("%3d: Initializing itables for %s", ++initialize_count,
1002 _klass->name()->as_C_string());
1003
1004
1005 // Iterate through all interfaces
1006 int i;
1007 for(i = 0; i < num_interfaces; i++) {
1008 itableOffsetEntry* ioe = offset_entry(i);
1009 HandleMark hm(THREAD);
1010 KlassHandle interf_h (THREAD, ioe->interface_klass());
1011 assert(interf_h() != NULL && ioe->offset() != 0, "bad offset entry in itable");
1012 initialize_itable_for_interface(ioe->offset(), interf_h, checkconstraints, CHECK);
1013 }
1014
1015 }
1016 // Check that the last entry is empty
1017 itableOffsetEntry* ioe = offset_entry(size_offset_table() - 1);
1018 guarantee(ioe->interface_klass() == NULL && ioe->offset() == 0, "terminator entry missing");
1019 }
1020
1021
1022 inline bool interface_method_needs_itable_index(Method* m) {
1023 if (m->is_static()) return false; // e.g., Stream.empty
1024 if (m->is_initializer()) return false; // <init> or <clinit>
1025 // If an interface redeclares a method from java.lang.Object,
1026 // it should already have a vtable index, don't touch it.
1027 // e.g., CharSequence.toString (from initialize_vtable)
1028 // if (m->has_vtable_index()) return false; // NO!
1029 return true;
1030 }
1031
1032 int klassItable::assign_itable_indices_for_interface(Klass* klass) {
1033 // an interface does not have an itable, but its methods need to be numbered
1034 if (TraceItables) tty->print_cr("%3d: Initializing itable for interface %s", ++initialize_count,
1035 klass->name()->as_C_string());
1036 Array<Method*>* methods = InstanceKlass::cast(klass)->methods();
1037 int nof_methods = methods->length();
1038 int ime_num = 0;
1039 for (int i = 0; i < nof_methods; i++) {
1040 Method* m = methods->at(i);
1041 if (interface_method_needs_itable_index(m)) {
1042 assert(!m->is_final_method(), "no final interface methods");
1043 // If m is already assigned a vtable index, do not disturb it.
1044 if (TraceItables && Verbose) {
1045 ResourceMark rm;
1046 const char* sig = (m != NULL) ? m->name_and_sig_as_C_string() : "<NULL>";
1047 if (m->has_vtable_index()) {
1048 tty->print("itable index %d for method: %s, flags: ", m->vtable_index(), sig);
1049 } else {
1050 tty->print("itable index %d for method: %s, flags: ", ime_num, sig);
1051 }
1052 if (m != NULL) {
1053 m->access_flags().print_on(tty);
1054 if (m->is_default_method()) {
1055 tty->print("default ");
1056 }
1057 if (m->is_overpass()) {
1058 tty->print("overpass");
1059 }
1060 }
1061 tty->cr();
1062 }
1063 if (!m->has_vtable_index()) {
1064 assert(m->vtable_index() == Method::pending_itable_index, "set by initialize_vtable");
1065 m->set_itable_index(ime_num);
1066 // Progress to next itable entry
1067 ime_num++;
1068 }
1069 }
1070 }
1071 assert(ime_num == method_count_for_interface(klass), "proper sizing");
1072 return ime_num;
1073 }
1074
1075 int klassItable::method_count_for_interface(Klass* interf) {
1076 assert(interf->oop_is_instance(), "must be");
1077 assert(interf->is_interface(), "must be");
1078 Array<Method*>* methods = InstanceKlass::cast(interf)->methods();
1079 int nof_methods = methods->length();
1080 while (nof_methods > 0) {
1081 Method* m = methods->at(nof_methods-1);
1082 if (m->has_itable_index()) {
1083 int length = m->itable_index() + 1;
1084 #ifdef ASSERT
1085 while (nof_methods = 0) {
1086 m = methods->at(--nof_methods);
1087 assert(!m->has_itable_index() || m->itable_index() < length, "");
1088 }
1089 #endif //ASSERT
1090 return length; // return the rightmost itable index, plus one
1091 }
1092 nof_methods -= 1;
1093 }
1094 // no methods have itable indices
1095 return 0;
1096 }
1097
1098
1099 void klassItable::initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS) {
1100 Array<Method*>* methods = InstanceKlass::cast(interf_h())->methods();
1101 int nof_methods = methods->length();
1102 HandleMark hm;
1103 assert(nof_methods > 0, "at least one method must exist for interface to be in vtable");
1104 Handle interface_loader (THREAD, InstanceKlass::cast(interf_h())->class_loader());
1105
1106 int ime_count = method_count_for_interface(interf_h());
1107 for (int i = 0; i < nof_methods; i++) {
1108 Method* m = methods->at(i);
1109 methodHandle target;
1110 if (m->has_itable_index()) {
1111 // This search must match the runtime resolution, i.e. selection search for invokeinterface
1112 // to correctly enforce loader constraints for interface method inheritance
1113 LinkResolver::lookup_instance_method_in_klasses(target, _klass, m->name(), m->signature(), CHECK);
1114 }
1115 if (target == NULL || !target->is_public() || target->is_abstract()) {
1116 // Entry does not resolve. Leave it empty for AbstractMethodError.
1117 if (!(target == NULL) && !target->is_public()) {
1118 // Stuff an IllegalAccessError throwing method in there instead.
1119 itableOffsetEntry::method_entry(_klass(), method_table_offset)[m->itable_index()].
1120 initialize(Universe::throw_illegal_access_error());
1121 }
1122 } else {
1123 // Entry did resolve, check loader constraints before initializing
1124 // if checkconstraints requested
1125 if (checkconstraints) {
1126 Handle method_holder_loader (THREAD, target->method_holder()->class_loader());
1127 if (method_holder_loader() != interface_loader()) {
1128 ResourceMark rm(THREAD);
1129 Symbol* failed_type_symbol =
1130 SystemDictionary::check_signature_loaders(m->signature(),
1131 method_holder_loader,
1132 interface_loader,
1133 true, CHECK);
1134 if (failed_type_symbol != NULL) {
1135 const char* msg = "loader constraint violation in interface "
1136 "itable initialization: when resolving method \"%s\" the class"
1137 " loader (instance of %s) of the current class, %s, "
1138 "and the class loader (instance of %s) for interface "
1139 "%s have different Class objects for the type %s "
1140 "used in the signature";
1141 char* sig = target()->name_and_sig_as_C_string();
1142 const char* loader1 = SystemDictionary::loader_name(method_holder_loader());
1143 char* current = _klass->name()->as_C_string();
1144 const char* loader2 = SystemDictionary::loader_name(interface_loader());
1145 char* iface = InstanceKlass::cast(interf_h())->name()->as_C_string();
1146 char* failed_type_name = failed_type_symbol->as_C_string();
1147 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
1148 strlen(current) + strlen(loader2) + strlen(iface) +
1149 strlen(failed_type_name);
1150 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
1151 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2,
1152 iface, failed_type_name);
1153 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
1154 }
1155 }
1156 }
1157
1158 // ime may have moved during GC so recalculate address
1159 int ime_num = m->itable_index();
1160 assert(ime_num < ime_count, "oob");
1161 itableOffsetEntry::method_entry(_klass(), method_table_offset)[ime_num].initialize(target());
1162 if (TraceItables && Verbose) {
1163 ResourceMark rm(THREAD);
1164 if (target() != NULL) {
1165 char* sig = target()->name_and_sig_as_C_string();
1166 tty->print("interface: %s, ime_num: %d, target: %s, method_holder: %s ",
1167 interf_h()->internal_name(), ime_num, sig,
1168 target()->method_holder()->internal_name());
1169 tty->print("target_method flags: ");
1170 target()->access_flags().print_on(tty);
1171 if (target()->is_default_method()) {
1172 tty->print("default ");
1173 }
1174 tty->cr();
1175 }
1176 }
1177 }
1178 }
1179 }
1180
1181 // Update entry for specific Method*
1182 void klassItable::initialize_with_method(Method* m) {
1183 itableMethodEntry* ime = method_entry(0);
1184 for(int i = 0; i < _size_method_table; i++) {
1185 if (ime->method() == m) {
1186 ime->initialize(m);
1187 }
1188 ime++;
1189 }
1190 }
1191
1192 #if INCLUDE_JVMTI
1193 void klassItable::adjust_method_entries(Method** old_methods, Method** new_methods,
1194 int methods_length, bool * trace_name_printed) {
1195 // search the itable for uses of either obsolete or EMCP methods
1196 for (int j = 0; j < methods_length; j++) {
1197 Method* old_method = old_methods[j];
1198 Method* new_method = new_methods[j];
1199 itableMethodEntry* ime = method_entry(0);
1200
1201 // The itable can describe more than one interface and the same
1202 // method signature can be specified by more than one interface.
1203 // This means we have to do an exhaustive search to find all the
1204 // old_method references.
1205 for (int i = 0; i < _size_method_table; i++) {
1206 if (ime->method() == old_method) {
1207 ime->initialize(new_method);
1208
1209 if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
1210 if (!(*trace_name_printed)) {
1211 // RC_TRACE_MESG macro has an embedded ResourceMark
1212 RC_TRACE_MESG(("adjust: name=%s",
1213 old_method->method_holder()->external_name()));
1214 *trace_name_printed = true;
1215 }
1216 // RC_TRACE macro has an embedded ResourceMark
1217 RC_TRACE(0x00200000, ("itable method update: %s(%s)",
1218 new_method->name()->as_C_string(),
1219 new_method->signature()->as_C_string()));
1220 }
1221 // cannot 'break' here; see for-loop comment above.
1222 }
1223 ime++;
1224 }
1225 }
1226 }
1227
1228 // an itable should never contain old or obsolete methods
1229 bool klassItable::check_no_old_or_obsolete_entries() {
1230 itableMethodEntry* ime = method_entry(0);
1231 for (int i = 0; i < _size_method_table; i++) {
1232 Method* m = ime->method();
1233 if (m != NULL &&
1234 (NOT_PRODUCT(!m->is_valid() ||) m->is_old() || m->is_obsolete())) {
1235 return false;
1236 }
1237 ime++;
1238 }
1239 return true;
1240 }
1241
1242 void klassItable::dump_itable() {
1243 itableMethodEntry* ime = method_entry(0);
1244 tty->print_cr("itable dump --");
1245 for (int i = 0; i < _size_method_table; i++) {
1246 Method* m = ime->method();
1247 if (m != NULL) {
1248 tty->print(" (%5d) ", i);
1249 m->access_flags().print_on(tty);
1250 if (m->is_default_method()) {
1251 tty->print("default ");
1252 }
1253 tty->print(" -- ");
1254 m->print_name(tty);
1255 tty->cr();
1256 }
1257 ime++;
1258 }
1259 }
1260 #endif // INCLUDE_JVMTI
1261
1262
1263 // Setup
1264 class InterfaceVisiterClosure : public StackObj {
1265 public:
1266 virtual void doit(Klass* intf, int method_count) = 0;
1267 };
1268
1269 // Visit all interfaces with at least one itable method
1270 void visit_all_interfaces(Array<Klass*>* transitive_intf, InterfaceVisiterClosure *blk) {
1271 // Handle array argument
1272 for(int i = 0; i < transitive_intf->length(); i++) {
1273 Klass* intf = transitive_intf->at(i);
1274 assert(intf->is_interface(), "sanity check");
1275
1276 // Find no. of itable methods
1277 int method_count = 0;
1278 // method_count = klassItable::method_count_for_interface(intf);
1279 Array<Method*>* methods = InstanceKlass::cast(intf)->methods();
1280 if (methods->length() > 0) {
1281 for (int i = methods->length(); --i >= 0; ) {
1282 if (interface_method_needs_itable_index(methods->at(i))) {
1283 method_count++;
1284 }
1285 }
1286 }
1287
1288 // Only count interfaces with at least one method
1289 if (method_count > 0) {
1290 blk->doit(intf, method_count);
1291 }
1292 }
1293 }
1294
1295 class CountInterfacesClosure : public InterfaceVisiterClosure {
1296 private:
1297 int _nof_methods;
1298 int _nof_interfaces;
1299 public:
1300 CountInterfacesClosure() { _nof_methods = 0; _nof_interfaces = 0; }
1301
1302 int nof_methods() const { return _nof_methods; }
1303 int nof_interfaces() const { return _nof_interfaces; }
1304
1305 void doit(Klass* intf, int method_count) { _nof_methods += method_count; _nof_interfaces++; }
1306 };
1307
1308 class SetupItableClosure : public InterfaceVisiterClosure {
1309 private:
1310 itableOffsetEntry* _offset_entry;
1311 itableMethodEntry* _method_entry;
1312 address _klass_begin;
1313 public:
1314 SetupItableClosure(address klass_begin, itableOffsetEntry* offset_entry, itableMethodEntry* method_entry) {
1315 _klass_begin = klass_begin;
1316 _offset_entry = offset_entry;
1317 _method_entry = method_entry;
1318 }
1319
1320 itableMethodEntry* method_entry() const { return _method_entry; }
1321
1322 void doit(Klass* intf, int method_count) {
1323 int offset = ((address)_method_entry) - _klass_begin;
1324 _offset_entry->initialize(intf, offset);
1325 _offset_entry++;
1326 _method_entry += method_count;
1327 }
1328 };
1329
1330 int klassItable::compute_itable_size(Array<Klass*>* transitive_interfaces) {
1331 // Count no of interfaces and total number of interface methods
1332 CountInterfacesClosure cic;
1333 visit_all_interfaces(transitive_interfaces, &cic);
1334
1335 // There's alway an extra itable entry so we can null-terminate it.
1336 int itable_size = calc_itable_size(cic.nof_interfaces() + 1, cic.nof_methods());
1337
1338 // Statistics
1339 update_stats(itable_size * HeapWordSize);
1340
1341 return itable_size;
1342 }
1343
1344
1345 // Fill out offset table and interface klasses into the itable space
1346 void klassItable::setup_itable_offset_table(instanceKlassHandle klass) {
1347 if (klass->itable_length() == 0) return;
1348 assert(!klass->is_interface(), "Should have zero length itable");
1349
1350 // Count no of interfaces and total number of interface methods
1351 CountInterfacesClosure cic;
1352 visit_all_interfaces(klass->transitive_interfaces(), &cic);
1353 int nof_methods = cic.nof_methods();
1354 int nof_interfaces = cic.nof_interfaces();
1355
1356 // Add one extra entry so we can null-terminate the table
1357 nof_interfaces++;
1358
1359 assert(compute_itable_size(klass->transitive_interfaces()) ==
1360 calc_itable_size(nof_interfaces, nof_methods),
1361 "mismatch calculation of itable size");
1362
1363 // Fill-out offset table
1364 itableOffsetEntry* ioe = (itableOffsetEntry*)klass->start_of_itable();
1365 itableMethodEntry* ime = (itableMethodEntry*)(ioe + nof_interfaces);
1366 intptr_t* end = klass->end_of_itable();
1367 assert((oop*)(ime + nof_methods) <= (oop*)klass->start_of_nonstatic_oop_maps(), "wrong offset calculation (1)");
1368 assert((oop*)(end) == (oop*)(ime + nof_methods), "wrong offset calculation (2)");
1369
1370 // Visit all interfaces and initialize itable offset table
1371 SetupItableClosure sic((address)klass(), ioe, ime);
1372 visit_all_interfaces(klass->transitive_interfaces(), &sic);
1373
1374 #ifdef ASSERT
1375 ime = sic.method_entry();
1376 oop* v = (oop*) klass->end_of_itable();
1377 assert( (oop*)(ime) == v, "wrong offset calculation (2)");
1378 #endif
1379 }
1380
1381
1382 // inverse to itable_index
1383 Method* klassItable::method_for_itable_index(Klass* intf, int itable_index) {
1384 assert(InstanceKlass::cast(intf)->is_interface(), "sanity check");
1385 assert(intf->verify_itable_index(itable_index), "");
1386 Array<Method*>* methods = InstanceKlass::cast(intf)->methods();
1387
1388 if (itable_index < 0 || itable_index >= method_count_for_interface(intf))
1389 return NULL; // help caller defend against bad indices
1390
1391 int index = itable_index;
1392 Method* m = methods->at(index);
1393 int index2 = -1;
1394 while (!m->has_itable_index() ||
1395 (index2 = m->itable_index()) != itable_index) {
1396 assert(index2 < itable_index, "monotonic");
1397 if (++index == methods->length())
1398 return NULL;
1399 m = methods->at(index);
1400 }
1401 assert(m->itable_index() == itable_index, "correct inverse");
1402
1403 return m;
1404 }
1405
1406 void klassVtable::verify(outputStream* st, bool forced) {
1407 // make sure table is initialized
1408 if (!Universe::is_fully_initialized()) return;
1409 #ifndef PRODUCT
1410 // avoid redundant verifies
1411 if (!forced && _verify_count == Universe::verify_count()) return;
1412 _verify_count = Universe::verify_count();
1413 #endif
1414 oop* end_of_obj = (oop*)_klass() + _klass()->size();
1415 oop* end_of_vtable = (oop *)&table()[_length];
1416 if (end_of_vtable > end_of_obj) {
1417 fatal(err_msg("klass %s: klass object too short (vtable extends beyond "
1418 "end)", _klass->internal_name()));
1419 }
1420
1421 for (int i = 0; i < _length; i++) table()[i].verify(this, st);
1422 // verify consistency with superKlass vtable
1423 Klass* super = _klass->super();
1424 if (super != NULL) {
1425 InstanceKlass* sk = InstanceKlass::cast(super);
1426 klassVtable* vt = sk->vtable();
1427 for (int i = 0; i < vt->length(); i++) {
1428 verify_against(st, vt, i);
1429 }
1430 }
1431 }
1432
1433 void klassVtable::verify_against(outputStream* st, klassVtable* vt, int index) {
1434 vtableEntry* vte = &vt->table()[index];
1435 if (vte->method()->name() != table()[index].method()->name() ||
1436 vte->method()->signature() != table()[index].method()->signature()) {
1437 fatal("mismatched name/signature of vtable entries");
1438 }
1439 }
1440
1441 #ifndef PRODUCT
1442 void klassVtable::print() {
1443 ResourceMark rm;
1444 tty->print("klassVtable for klass %s (length %d):\n", _klass->internal_name(), length());
1445 for (int i = 0; i < length(); i++) {
1446 table()[i].print();
1447 tty->cr();
1448 }
1449 }
1450 #endif
1451
1452 void vtableEntry::verify(klassVtable* vt, outputStream* st) {
1453 NOT_PRODUCT(FlagSetting fs(IgnoreLockingAssertions, true));
1454 assert(method() != NULL, "must have set method");
1455 method()->verify();
1456 // we sub_type, because it could be a miranda method
1457 if (!vt->klass()->is_subtype_of(method()->method_holder())) {
1458 #ifndef PRODUCT
1459 print();
1460 #endif
1461 fatal(err_msg("vtableEntry " PTR_FORMAT ": method is from subclass", this));
1462 }
1463 }
1464
1465 #ifndef PRODUCT
1466
1467 void vtableEntry::print() {
1468 ResourceMark rm;
1469 tty->print("vtableEntry %s: ", method()->name()->as_C_string());
1470 if (Verbose) {
1471 tty->print("m %#lx ", (address)method());
1472 }
1473 }
1474
1475 class VtableStats : AllStatic {
1476 public:
1477 static int no_klasses; // # classes with vtables
1478 static int no_array_klasses; // # array classes
1479 static int no_instance_klasses; // # instanceKlasses
1480 static int sum_of_vtable_len; // total # of vtable entries
1481 static int sum_of_array_vtable_len; // total # of vtable entries in array klasses only
1482 static int fixed; // total fixed overhead in bytes
1483 static int filler; // overhead caused by filler bytes
1484 static int entries; // total bytes consumed by vtable entries
1485 static int array_entries; // total bytes consumed by array vtable entries
1486
1487 static void do_class(Klass* k) {
1488 Klass* kl = k;
1489 klassVtable* vt = kl->vtable();
1490 if (vt == NULL) return;
1491 no_klasses++;
1492 if (kl->oop_is_instance()) {
1493 no_instance_klasses++;
1494 kl->array_klasses_do(do_class);
1495 }
1496 if (kl->oop_is_array()) {
1497 no_array_klasses++;
1498 sum_of_array_vtable_len += vt->length();
1499 }
1500 sum_of_vtable_len += vt->length();
1501 }
1502
1503 static void compute() {
1504 SystemDictionary::classes_do(do_class);
1505 fixed = no_klasses * oopSize; // vtable length
1506 // filler size is a conservative approximation
1507 filler = oopSize * (no_klasses - no_instance_klasses) * (sizeof(InstanceKlass) - sizeof(ArrayKlass) - 1);
1508 entries = sizeof(vtableEntry) * sum_of_vtable_len;
1509 array_entries = sizeof(vtableEntry) * sum_of_array_vtable_len;
1510 }
1511 };
1512
1513 int VtableStats::no_klasses = 0;
1514 int VtableStats::no_array_klasses = 0;
1515 int VtableStats::no_instance_klasses = 0;
1516 int VtableStats::sum_of_vtable_len = 0;
1517 int VtableStats::sum_of_array_vtable_len = 0;
1518 int VtableStats::fixed = 0;
1519 int VtableStats::filler = 0;
1520 int VtableStats::entries = 0;
1521 int VtableStats::array_entries = 0;
1522
1523 void klassVtable::print_statistics() {
1524 ResourceMark rm;
1525 HandleMark hm;
1526 VtableStats::compute();
1527 tty->print_cr("vtable statistics:");
1528 tty->print_cr("%6d classes (%d instance, %d array)", VtableStats::no_klasses, VtableStats::no_instance_klasses, VtableStats::no_array_klasses);
1529 int total = VtableStats::fixed + VtableStats::filler + VtableStats::entries;
1530 tty->print_cr("%6d bytes fixed overhead (refs + vtable object header)", VtableStats::fixed);
1531 tty->print_cr("%6d bytes filler overhead", VtableStats::filler);
1532 tty->print_cr("%6d bytes for vtable entries (%d for arrays)", VtableStats::entries, VtableStats::array_entries);
1533 tty->print_cr("%6d bytes total", total);
1534 }
1535
1536 int klassItable::_total_classes; // Total no. of classes with itables
1537 long klassItable::_total_size; // Total no. of bytes used for itables
1538
1539 void klassItable::print_statistics() {
1540 tty->print_cr("itable statistics:");
1541 tty->print_cr("%6d classes with itables", _total_classes);
1542 tty->print_cr("%6d K uses for itables (average by class: %d bytes)", _total_size / K, _total_size / _total_classes);
1543 }
1544
1545 #endif // PRODUCT