1 /*
2 * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/systemDictionary.hpp"
27 #include "classfile/vmSymbols.hpp"
28 #include "memory/gcLocker.hpp"
29 #include "memory/resourceArea.hpp"
30 #include "memory/universe.inline.hpp"
31 #include "oops/instanceKlass.hpp"
32 #include "oops/klassVtable.hpp"
33 #include "oops/method.hpp"
34 #include "oops/objArrayOop.hpp"
35 #include "oops/oop.inline.hpp"
36 #include "prims/jvmtiRedefineClassesTrace.hpp"
37 #include "runtime/arguments.hpp"
38 #include "runtime/handles.inline.hpp"
39 #include "utilities/copy.hpp"
40
41 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
42
43 inline InstanceKlass* klassVtable::ik() const {
44 Klass* k = _klass();
45 assert(k->oop_is_instance(), "not an InstanceKlass");
46 return (InstanceKlass*)k;
47 }
48
49
50 // this function computes the vtable size (including the size needed for miranda
51 // methods) and the number of miranda methods in this class.
52 // Note on Miranda methods: Let's say there is a class C that implements
53 // interface I, and none of C's superclasses implements I.
54 // Let's say there is an abstract method m in I that neither C
55 // nor any of its super classes implement (i.e there is no method of any access,
56 // with the same name and signature as m), then m is a Miranda method which is
57 // entered as a public abstract method in C's vtable. From then on it should
58 // treated as any other public method in C for method over-ride purposes.
59 void klassVtable::compute_vtable_size_and_num_mirandas(
60 int* vtable_length_ret, int* num_new_mirandas,
61 GrowableArray<Method*>* all_mirandas, Klass* super,
62 Array<Method*>* methods, AccessFlags class_flags,
63 Handle classloader, Symbol* classname, Array<Klass*>* local_interfaces,
64 TRAPS) {
65 No_Safepoint_Verifier nsv;
66
67 // set up default result values
68 int vtable_length = 0;
69
70 // start off with super's vtable length
71 InstanceKlass* sk = (InstanceKlass*)super;
72 vtable_length = super == NULL ? 0 : sk->vtable_length();
73
74 // go thru each method in the methods table to see if it needs a new entry
75 int len = methods->length();
76 for (int i = 0; i < len; i++) {
77 assert(methods->at(i)->is_method(), "must be a Method*");
78 methodHandle mh(THREAD, methods->at(i));
79
80 if (needs_new_vtable_entry(mh, super, classloader, classname, class_flags, THREAD)) {
81 vtable_length += vtableEntry::size(); // we need a new entry
82 }
83 }
84
85 GrowableArray<Method*> new_mirandas(20);
86 // compute the number of mirandas methods that must be added to the end
87 get_mirandas(&new_mirandas, all_mirandas, super, methods, NULL, local_interfaces);
88 *num_new_mirandas = new_mirandas.length();
89
90 // Interfaces do not need interface methods in their vtables
91 // This includes miranda methods and during later processing, default methods
92 if (!class_flags.is_interface()) {
93 vtable_length += *num_new_mirandas * vtableEntry::size();
94 }
95
96 if (Universe::is_bootstrapping() && vtable_length == 0) {
97 // array classes don't have their superclass set correctly during
98 // bootstrapping
99 vtable_length = Universe::base_vtable_size();
100 }
101
102 if (super == NULL && vtable_length != Universe::base_vtable_size()) {
103 if (Universe::is_bootstrapping()) {
104 // Someone is attempting to override java.lang.Object incorrectly on the
105 // bootclasspath. The JVM cannot recover from this error including throwing
106 // an exception
107 vm_exit_during_initialization("Incompatible definition of java.lang.Object");
108 } else {
109 // Someone is attempting to redefine java.lang.Object incorrectly. The
110 // only way this should happen is from
111 // SystemDictionary::resolve_from_stream(), which will detect this later
112 // and throw a security exception. So don't assert here to let
113 // the exception occur.
114 vtable_length = Universe::base_vtable_size();
115 }
116 }
117 assert(vtable_length % vtableEntry::size() == 0, "bad vtable length");
118 assert(vtable_length >= Universe::base_vtable_size(), "vtable too small");
119
120 *vtable_length_ret = vtable_length;
121 }
122
123 int klassVtable::index_of(Method* m, int len) const {
124 assert(m->has_vtable_index(), "do not ask this of non-vtable methods");
125 return m->vtable_index();
126 }
127
128 // Copy super class's vtable to the first part (prefix) of this class's vtable,
129 // and return the number of entries copied. Expects that 'super' is the Java
130 // super class (arrays can have "array" super classes that must be skipped).
131 int klassVtable::initialize_from_super(KlassHandle super) {
132 if (super.is_null()) {
133 return 0;
134 } else {
135 // copy methods from superKlass
136 // can't inherit from array class, so must be InstanceKlass
137 assert(super->oop_is_instance(), "must be instance klass");
138 InstanceKlass* sk = (InstanceKlass*)super();
139 klassVtable* superVtable = sk->vtable();
140 assert(superVtable->length() <= _length, "vtable too short");
141 #ifdef ASSERT
142 superVtable->verify(tty, true);
143 #endif
144 superVtable->copy_vtable_to(table());
145 #ifndef PRODUCT
146 if (PrintVtables && Verbose) {
147 ResourceMark rm;
148 tty->print_cr("copy vtable from %s to %s size %d", sk->internal_name(), klass()->internal_name(), _length);
149 }
150 #endif
151 return superVtable->length();
152 }
153 }
154
155 //
156 // Revised lookup semantics introduced 1.3 (Kestrel beta)
157 void klassVtable::initialize_vtable(bool checkconstraints, TRAPS) {
158
159 // Note: Arrays can have intermediate array supers. Use java_super to skip them.
160 KlassHandle super (THREAD, klass()->java_super());
161 int nofNewEntries = 0;
162
163 if (PrintVtables && !klass()->oop_is_array()) {
164 ResourceMark rm(THREAD);
165 tty->print_cr("Initializing: %s", _klass->name()->as_C_string());
166 }
167
168 #ifdef ASSERT
169 oop* end_of_obj = (oop*)_klass() + _klass()->size();
170 oop* end_of_vtable = (oop*)&table()[_length];
171 assert(end_of_vtable <= end_of_obj, "vtable extends beyond end");
172 #endif
173
174 if (Universe::is_bootstrapping()) {
175 // just clear everything
176 for (int i = 0; i < _length; i++) table()[i].clear();
177 return;
178 }
179
180 int super_vtable_len = initialize_from_super(super);
181 if (klass()->oop_is_array()) {
182 assert(super_vtable_len == _length, "arrays shouldn't introduce new methods");
183 } else {
184 assert(_klass->oop_is_instance(), "must be InstanceKlass");
185
186 Array<Method*>* methods = ik()->methods();
187 int len = methods->length();
188 int initialized = super_vtable_len;
189
190 // Check each of this class's methods against super;
191 // if override, replace in copy of super vtable, otherwise append to end
192 for (int i = 0; i < len; i++) {
193 // update_inherited_vtable can stop for gc - ensure using handles
194 HandleMark hm(THREAD);
195 assert(methods->at(i)->is_method(), "must be a Method*");
196 methodHandle mh(THREAD, methods->at(i));
197
198 bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, -1, checkconstraints, CHECK);
199
200 if (needs_new_entry) {
201 put_method_at(mh(), initialized);
202 mh()->set_vtable_index(initialized); // set primary vtable index
203 initialized++;
204 }
205 }
206
207 // update vtable with default_methods
208 Array<Method*>* default_methods = ik()->default_methods();
209 if (default_methods != NULL) {
210 len = default_methods->length();
211 if (len > 0) {
212 Array<int>* def_vtable_indices = NULL;
213 if ((def_vtable_indices = ik()->default_vtable_indices()) == NULL) {
214 def_vtable_indices = ik()->create_new_default_vtable_indices(len, CHECK);
215 } else {
216 assert(def_vtable_indices->length() == len, "reinit vtable len?");
217 }
218 for (int i = 0; i < len; i++) {
219 HandleMark hm(THREAD);
220 assert(default_methods->at(i)->is_method(), "must be a Method*");
221 methodHandle mh(THREAD, default_methods->at(i));
222
223 bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, i, checkconstraints, CHECK);
224
225 // needs new entry
226 if (needs_new_entry) {
227 put_method_at(mh(), initialized);
228 def_vtable_indices->at_put(i, initialized); //set vtable index
229 initialized++;
230 }
231 }
232 }
233 }
234
235 // add miranda methods; it will also return the updated initialized
236 // Interfaces do not need interface methods in their vtables
237 // This includes miranda methods and during later processing, default methods
238 if (!ik()->is_interface()) {
239 initialized = fill_in_mirandas(initialized);
240 }
241
242 // In class hierarchies where the accessibility is not increasing (i.e., going from private ->
243 // package_private -> public/protected), the vtable might actually be smaller than our initial
244 // calculation.
245 assert(initialized <= _length, "vtable initialization failed");
246 for(;initialized < _length; initialized++) {
247 put_method_at(NULL, initialized);
248 }
249 NOT_PRODUCT(verify(tty, true));
250 }
251 }
252
253 // Called for cases where a method does not override its superclass' vtable entry
254 // For bytecodes not produced by javac together it is possible that a method does not override
255 // the superclass's method, but might indirectly override a super-super class's vtable entry
256 // If none found, return a null superk, else return the superk of the method this does override
257 // For public and protected methods: if they override a superclass, they will
258 // also be overridden themselves appropriately.
259 // Private methods do not override and are not overridden.
260 // Package Private methods are trickier:
261 // e.g. P1.A, pub m
262 // P2.B extends A, package private m
263 // P1.C extends B, public m
264 // P1.C.m needs to override P1.A.m and can not override P2.B.m
265 // Therefore: all package private methods need their own vtable entries for
266 // them to be the root of an inheritance overriding decision
267 // Package private methods may also override other vtable entries
268 InstanceKlass* klassVtable::find_transitive_override(InstanceKlass* initialsuper, methodHandle target_method,
269 int vtable_index, Handle target_loader, Symbol* target_classname, Thread * THREAD) {
270 InstanceKlass* superk = initialsuper;
271 while (superk != NULL && superk->super() != NULL) {
272 InstanceKlass* supersuperklass = InstanceKlass::cast(superk->super());
273 klassVtable* ssVtable = supersuperklass->vtable();
274 if (vtable_index < ssVtable->length()) {
275 Method* super_method = ssVtable->method_at(vtable_index);
276 #ifndef PRODUCT
277 Symbol* name= target_method()->name();
278 Symbol* signature = target_method()->signature();
279 assert(super_method->name() == name && super_method->signature() == signature, "vtable entry name/sig mismatch");
280 #endif
281 if (supersuperklass->is_override(super_method, target_loader, target_classname, THREAD)) {
282 #ifndef PRODUCT
283 if (PrintVtables && Verbose) {
284 ResourceMark rm(THREAD);
285 char* sig = target_method()->name_and_sig_as_C_string();
286 tty->print("transitive overriding superclass %s with %s::%s index %d, original flags: ",
287 supersuperklass->internal_name(),
288 _klass->internal_name(), sig, vtable_index);
289 super_method->access_flags().print_on(tty);
290 if (super_method->is_default_method()) {
291 tty->print("default ");
292 }
293 tty->print("overriders flags: ");
294 target_method->access_flags().print_on(tty);
295 if (target_method->is_default_method()) {
296 tty->print("default ");
297 }
298 }
299 #endif /*PRODUCT*/
300 break; // return found superk
301 }
302 } else {
303 // super class has no vtable entry here, stop transitive search
304 superk = (InstanceKlass*)NULL;
305 break;
306 }
307 // if no override found yet, continue to search up
308 superk = InstanceKlass::cast(superk->super());
309 }
310
311 return superk;
312 }
313
314 // Update child's copy of super vtable for overrides
315 // OR return true if a new vtable entry is required.
316 // Only called for InstanceKlass's, i.e. not for arrays
317 // If that changed, could not use _klass as handle for klass
318 bool klassVtable::update_inherited_vtable(InstanceKlass* klass, methodHandle target_method,
319 int super_vtable_len, int default_index,
320 bool checkconstraints, TRAPS) {
321 ResourceMark rm;
322 bool allocate_new = true;
323 assert(klass->oop_is_instance(), "must be InstanceKlass");
324
325 Array<int>* def_vtable_indices = NULL;
326 bool is_default = false;
327 // default methods are concrete methods in superinterfaces which are added to the vtable
328 // with their real method_holder
329 // Since vtable and itable indices share the same storage, don't touch
330 // the default method's real vtable/itable index
331 // default_vtable_indices stores the vtable value relative to this inheritor
332 if (default_index >= 0 ) {
333 is_default = true;
334 def_vtable_indices = klass->default_vtable_indices();
335 assert(def_vtable_indices != NULL, "def vtable alloc?");
336 assert(default_index <= def_vtable_indices->length(), "def vtable len?");
337 } else {
338 assert(klass == target_method()->method_holder(), "caller resp.");
339 // Initialize the method's vtable index to "nonvirtual".
340 // If we allocate a vtable entry, we will update it to a non-negative number.
341 target_method()->set_vtable_index(Method::nonvirtual_vtable_index);
342 }
343
344 // Static and <init> methods are never in
345 if (target_method()->is_static() || target_method()->name() == vmSymbols::object_initializer_name()) {
346 return false;
347 }
348
349 if (target_method->is_final_method(klass->access_flags())) {
350 // a final method never needs a new entry; final methods can be statically
351 // resolved and they have to be present in the vtable only if they override
352 // a super's method, in which case they re-use its entry
353 allocate_new = false;
354 } else if (klass->is_interface()) {
355 allocate_new = false; // see note below in needs_new_vtable_entry
356 // An interface never allocates new vtable slots, only inherits old ones.
357 // This method will either be assigned its own itable index later,
358 // or be assigned an inherited vtable index in the loop below.
359 // default methods inherited by classes store their vtable indices
360 // in the inheritor's default_vtable_indices
361 // default methods inherited by interfaces may already have a
362 // valid itable index, if so, don't change it
363 // overpass methods in an interface will be assigned an itable index later
364 // by an inheriting class
365 if (!is_default || !target_method()->has_itable_index()) {
366 target_method()->set_vtable_index(Method::pending_itable_index);
367 }
368 }
369
370 // we need a new entry if there is no superclass
371 if (klass->super() == NULL) {
372 return allocate_new;
373 }
374
375 // private methods in classes always have a new entry in the vtable
376 // specification interpretation since classic has
377 // private methods not overriding
378 // JDK8 adds private methods in interfaces which require invokespecial
379 if (target_method()->is_private()) {
380 return allocate_new;
381 }
382
383 // search through the vtable and update overridden entries
384 // Since check_signature_loaders acquires SystemDictionary_lock
385 // which can block for gc, once we are in this loop, use handles
386 // For classfiles built with >= jdk7, we now look for transitive overrides
387
388 Symbol* name = target_method()->name();
389 Symbol* signature = target_method()->signature();
390
391 KlassHandle target_klass(THREAD, target_method()->method_holder());
392 if (target_klass == NULL) {
393 target_klass = _klass;
394 }
395
396 Handle target_loader(THREAD, target_klass->class_loader());
397
398 Symbol* target_classname = target_klass->name();
399 for(int i = 0; i < super_vtable_len; i++) {
400 Method* super_method = method_at(i);
401 // Check if method name matches
402 if (super_method->name() == name && super_method->signature() == signature) {
403
404 // get super_klass for method_holder for the found method
405 InstanceKlass* super_klass = super_method->method_holder();
406
407 if (is_default
408 || ((super_klass->is_override(super_method, target_loader, target_classname, THREAD))
409 || ((klass->major_version() >= VTABLE_TRANSITIVE_OVERRIDE_VERSION)
410 && ((super_klass = find_transitive_override(super_klass,
411 target_method, i, target_loader,
412 target_classname, THREAD))
413 != (InstanceKlass*)NULL))))
414 {
415 // Package private methods always need a new entry to root their own
416 // overriding. They may also override other methods.
417 if (!target_method()->is_package_private()) {
418 allocate_new = false;
419 }
420
421 if (checkconstraints) {
422 // Override vtable entry if passes loader constraint check
423 // if loader constraint checking requested
424 // No need to visit his super, since he and his super
425 // have already made any needed loader constraints.
426 // Since loader constraints are transitive, it is enough
427 // to link to the first super, and we get all the others.
428 Handle super_loader(THREAD, super_klass->class_loader());
429
430 if (target_loader() != super_loader()) {
431 ResourceMark rm(THREAD);
432 Symbol* failed_type_symbol =
433 SystemDictionary::check_signature_loaders(signature, target_loader,
434 super_loader, true,
435 CHECK_(false));
436 if (failed_type_symbol != NULL) {
437 const char* msg = "loader constraint violation: when resolving "
438 "overridden method \"%s\" the class loader (instance"
439 " of %s) of the current class, %s, and its superclass loader "
440 "(instance of %s), have different Class objects for the type "
441 "%s used in the signature";
442 char* sig = target_method()->name_and_sig_as_C_string();
443 const char* loader1 = SystemDictionary::loader_name(target_loader());
444 char* current = target_klass->name()->as_C_string();
445 const char* loader2 = SystemDictionary::loader_name(super_loader());
446 char* failed_type_name = failed_type_symbol->as_C_string();
447 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
448 strlen(current) + strlen(loader2) + strlen(failed_type_name);
449 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
450 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2,
451 failed_type_name);
452 THROW_MSG_(vmSymbols::java_lang_LinkageError(), buf, false);
453 }
454 }
455 }
456
457 put_method_at(target_method(), i);
458 if (!is_default) {
459 target_method()->set_vtable_index(i);
460 } else {
461 if (def_vtable_indices != NULL) {
462 def_vtable_indices->at_put(default_index, i);
463 }
464 assert(super_method->is_default_method() || super_method->is_overpass()
465 || super_method->is_abstract(), "default override error");
466 }
467
468
469 #ifndef PRODUCT
470 if (PrintVtables && Verbose) {
471 ResourceMark rm(THREAD);
472 char* sig = target_method()->name_and_sig_as_C_string();
473 tty->print("overriding with %s::%s index %d, original flags: ",
474 target_klass->internal_name(), sig, i);
475 super_method->access_flags().print_on(tty);
476 if (super_method->is_default_method()) {
477 tty->print("default ");
478 }
479 if (super_method->is_overpass()) {
480 tty->print("overpass");
481 }
482 tty->print("overriders flags: ");
483 target_method->access_flags().print_on(tty);
484 if (target_method->is_default_method()) {
485 tty->print("default ");
486 }
487 if (target_method->is_overpass()) {
488 tty->print("overpass");
489 }
490 tty->cr();
491 }
492 #endif /*PRODUCT*/
493 } else {
494 // allocate_new = true; default. We might override one entry,
495 // but not override another. Once we override one, not need new
496 #ifndef PRODUCT
497 if (PrintVtables && Verbose) {
498 ResourceMark rm(THREAD);
499 char* sig = target_method()->name_and_sig_as_C_string();
500 tty->print("NOT overriding with %s::%s index %d, original flags: ",
501 target_klass->internal_name(), sig,i);
502 super_method->access_flags().print_on(tty);
503 if (super_method->is_default_method()) {
504 tty->print("default ");
505 }
506 if (super_method->is_overpass()) {
507 tty->print("overpass");
508 }
509 tty->print("overriders flags: ");
510 target_method->access_flags().print_on(tty);
511 if (target_method->is_default_method()) {
512 tty->print("default ");
513 }
514 if (target_method->is_overpass()) {
515 tty->print("overpass");
516 }
517 tty->cr();
518 }
519 #endif /*PRODUCT*/
520 }
521 }
522 }
523 return allocate_new;
524 }
525
526 void klassVtable::put_method_at(Method* m, int index) {
527 #ifndef PRODUCT
528 if (PrintVtables && Verbose) {
529 ResourceMark rm;
530 const char* sig = (m != NULL) ? m->name_and_sig_as_C_string() : "<NULL>";
531 tty->print("adding %s at index %d, flags: ", sig, index);
532 if (m != NULL) {
533 m->access_flags().print_on(tty);
534 if (m->is_default_method()) {
535 tty->print("default ");
536 }
537 if (m->is_overpass()) {
538 tty->print("overpass");
539 }
540 }
541 tty->cr();
542 }
543 #endif
544 table()[index].set(m);
545 }
546
547 // Find out if a method "m" with superclass "super", loader "classloader" and
548 // name "classname" needs a new vtable entry. Let P be a class package defined
549 // by "classloader" and "classname".
550 // NOTE: The logic used here is very similar to the one used for computing
551 // the vtables indices for a method. We cannot directly use that function because,
552 // we allocate the InstanceKlass at load time, and that requires that the
553 // superclass has been loaded.
554 // However, the vtable entries are filled in at link time, and therefore
555 // the superclass' vtable may not yet have been filled in.
556 bool klassVtable::needs_new_vtable_entry(methodHandle target_method,
557 Klass* super,
558 Handle classloader,
559 Symbol* classname,
560 AccessFlags class_flags,
561 TRAPS) {
562 if (class_flags.is_interface()) {
563 // Interfaces do not use vtables, except for java.lang.Object methods,
564 // so there is no point to assigning
565 // a vtable index to any of their local methods. If we refrain from doing this,
566 // we can use Method::_vtable_index to hold the itable index
567 return false;
568 }
569
570 if (target_method->is_final_method(class_flags) ||
571 // a final method never needs a new entry; final methods can be statically
572 // resolved and they have to be present in the vtable only if they override
573 // a super's method, in which case they re-use its entry
574 (target_method()->is_static()) ||
575 // static methods don't need to be in vtable
576 (target_method()->name() == vmSymbols::object_initializer_name())
577 // <init> is never called dynamically-bound
578 ) {
579 return false;
580 }
581
582 // Concrete interface methods do not need new entries, they override
583 // abstract method entries using default inheritance rules
584 if (target_method()->method_holder() != NULL &&
585 target_method()->method_holder()->is_interface() &&
586 !target_method()->is_abstract() ) {
587 return false;
588 }
589
590 // we need a new entry if there is no superclass
591 if (super == NULL) {
592 return true;
593 }
594
595 // private methods in classes always have a new entry in the vtable
596 // specification interpretation since classic has
597 // private methods not overriding
598 // JDK8 adds private methods in interfaces which require invokespecial
599 if (target_method()->is_private()) {
600 return true;
601 }
602
603 // Package private methods always need a new entry to root their own
604 // overriding. This allows transitive overriding to work.
605 if (target_method()->is_package_private()) {
606 return true;
607 }
608
609 // search through the super class hierarchy to see if we need
610 // a new entry
611 ResourceMark rm;
612 Symbol* name = target_method()->name();
613 Symbol* signature = target_method()->signature();
614 Klass* k = super;
615 Method* super_method = NULL;
616 InstanceKlass *holder = NULL;
617 Method* recheck_method = NULL;
618 while (k != NULL) {
619 // lookup through the hierarchy for a method with matching name and sign.
620 super_method = InstanceKlass::cast(k)->lookup_method(name, signature);
621 if (super_method == NULL) {
622 break; // we still have to search for a matching miranda method
623 }
624 // get the class holding the matching method
625 // make sure you use that class for is_override
626 InstanceKlass* superk = super_method->method_holder();
627 // we want only instance method matches
628 // pretend private methods are not in the super vtable
629 // since we do override around them: e.g. a.m pub/b.m private/c.m pub,
630 // ignore private, c.m pub does override a.m pub
631 // For classes that were not javac'd together, we also do transitive overriding around
632 // methods that have less accessibility
633 if ((!super_method->is_static()) &&
634 (!super_method->is_private())) {
635 if (superk->is_override(super_method, classloader, classname, THREAD)) {
636 return false;
637 // else keep looking for transitive overrides
638 }
639 }
640
641 // Start with lookup result and continue to search up
642 k = superk->super(); // haven't found an override match yet; continue to look
643 }
644
645 // if the target method is public or protected it may have a matching
646 // miranda method in the super, whose entry it should re-use.
647 // Actually, to handle cases that javac would not generate, we need
648 // this check for all access permissions.
649 InstanceKlass *sk = InstanceKlass::cast(super);
650 if (sk->has_miranda_methods()) {
651 if (sk->lookup_method_in_all_interfaces(name, signature, Klass::find_defaults) != NULL) {
652 return false; // found a matching miranda; we do not need a new entry
653 }
654 }
655 return true; // found no match; we need a new entry
656 }
657
658 // Support for miranda methods
659
660 // get the vtable index of a miranda method with matching "name" and "signature"
661 int klassVtable::index_of_miranda(Symbol* name, Symbol* signature) {
662 // search from the bottom, might be faster
663 for (int i = (length() - 1); i >= 0; i--) {
664 Method* m = table()[i].method();
665 if (is_miranda_entry_at(i) &&
666 m->name() == name && m->signature() == signature) {
667 return i;
668 }
669 }
670 return Method::invalid_vtable_index;
671 }
672
673 // check if an entry at an index is miranda
674 // requires that method m at entry be declared ("held") by an interface.
675 bool klassVtable::is_miranda_entry_at(int i) {
676 Method* m = method_at(i);
677 Klass* method_holder = m->method_holder();
678 InstanceKlass *mhk = InstanceKlass::cast(method_holder);
679
680 // miranda methods are public abstract instance interface methods in a class's vtable
681 if (mhk->is_interface()) {
682 assert(m->is_public(), "should be public");
683 assert(ik()->implements_interface(method_holder) , "this class should implement the interface");
684 // the search could find a miranda or a default method
685 if (is_miranda(m, ik()->methods(), ik()->default_methods(), ik()->super())) {
686 return true;
687 }
688 }
689 return false;
690 }
691
692 // check if a method is a miranda method, given a class's methods table,
693 // its default_method table and its super
694 // Miranda methods are calculated twice:
695 // first: before vtable size calculation: including abstract and default
696 // This is seen by default method creation
697 // Second: recalculated during vtable initialization: only abstract
698 // This is seen by link resolution and selection.
699 // "miranda" means not static, not defined by this class.
700 // private methods in interfaces do not belong in the miranda list.
701 // the caller must make sure that the method belongs to an interface implemented by the class
702 // Miranda methods only include public interface instance methods
703 // Not private methods, not static methods, not default == concrete abstract
704 // Miranda methods also do not include overpass methods in interfaces
705 bool klassVtable::is_miranda(Method* m, Array<Method*>* class_methods,
706 Array<Method*>* default_methods, Klass* super) {
707 if (m->is_static() || m->is_private() || m->is_overpass()) {
708 return false;
709 }
710 Symbol* name = m->name();
711 Symbol* signature = m->signature();
712
713 if (InstanceKlass::find_instance_method(class_methods, name, signature) == NULL) {
714 // did not find it in the method table of the current class
715 if ((default_methods == NULL) ||
716 InstanceKlass::find_method(default_methods, name, signature) == NULL) {
717 if (super == NULL) {
718 // super doesn't exist
719 return true;
720 }
721
722 Method* mo = InstanceKlass::cast(super)->lookup_method(name, signature);
723 while (mo != NULL && mo->access_flags().is_static()
724 && mo->method_holder() != NULL
725 && mo->method_holder()->super() != NULL)
726 {
727 mo = mo->method_holder()->super()->uncached_lookup_method(name, signature, Klass::find_overpass);
728 }
729 if (mo == NULL || mo->access_flags().is_private() ) {
730 // super class hierarchy does not implement it or protection is different
731 return true;
732 }
733 }
734 }
735
736 return false;
737 }
738
739 // Scans current_interface_methods for miranda methods that do not
740 // already appear in new_mirandas, or default methods, and are also not defined-and-non-private
741 // in super (superclass). These mirandas are added to all_mirandas if it is
742 // not null; in addition, those that are not duplicates of miranda methods
743 // inherited by super from its interfaces are added to new_mirandas.
744 // Thus, new_mirandas will be the set of mirandas that this class introduces,
745 // all_mirandas will be the set of all mirandas applicable to this class
746 // including all defined in superclasses.
747 void klassVtable::add_new_mirandas_to_lists(
748 GrowableArray<Method*>* new_mirandas, GrowableArray<Method*>* all_mirandas,
749 Array<Method*>* current_interface_methods, Array<Method*>* class_methods,
750 Array<Method*>* default_methods, Klass* super) {
751
752 // iterate thru the current interface's method to see if it a miranda
753 int num_methods = current_interface_methods->length();
754 for (int i = 0; i < num_methods; i++) {
755 Method* im = current_interface_methods->at(i);
756 bool is_duplicate = false;
757 int num_of_current_mirandas = new_mirandas->length();
758 // check for duplicate mirandas in different interfaces we implement
759 for (int j = 0; j < num_of_current_mirandas; j++) {
760 Method* miranda = new_mirandas->at(j);
761 if ((im->name() == miranda->name()) &&
762 (im->signature() == miranda->signature())) {
763 is_duplicate = true;
764 break;
765 }
766 }
767
768 if (!is_duplicate) { // we don't want duplicate miranda entries in the vtable
769 if (is_miranda(im, class_methods, default_methods, super)) { // is it a miranda at all?
770 InstanceKlass *sk = InstanceKlass::cast(super);
771 // check if it is a duplicate of a super's miranda
772 if (sk->lookup_method_in_all_interfaces(im->name(), im->signature(), Klass::find_defaults) == NULL) {
773 new_mirandas->append(im);
774 }
775 if (all_mirandas != NULL) {
776 all_mirandas->append(im);
777 }
778 }
779 }
780 }
781 }
782
783 void klassVtable::get_mirandas(GrowableArray<Method*>* new_mirandas,
784 GrowableArray<Method*>* all_mirandas,
785 Klass* super, Array<Method*>* class_methods,
786 Array<Method*>* default_methods,
787 Array<Klass*>* local_interfaces) {
788 assert((new_mirandas->length() == 0) , "current mirandas must be 0");
789
790 // iterate thru the local interfaces looking for a miranda
791 int num_local_ifs = local_interfaces->length();
792 for (int i = 0; i < num_local_ifs; i++) {
793 InstanceKlass *ik = InstanceKlass::cast(local_interfaces->at(i));
794 add_new_mirandas_to_lists(new_mirandas, all_mirandas,
795 ik->methods(), class_methods,
796 default_methods, super);
797 // iterate thru each local's super interfaces
798 Array<Klass*>* super_ifs = ik->transitive_interfaces();
799 int num_super_ifs = super_ifs->length();
800 for (int j = 0; j < num_super_ifs; j++) {
801 InstanceKlass *sik = InstanceKlass::cast(super_ifs->at(j));
802 add_new_mirandas_to_lists(new_mirandas, all_mirandas,
803 sik->methods(), class_methods,
804 default_methods, super);
805 }
806 }
807 }
808
809 // Discover miranda methods ("miranda" = "interface abstract, no binding"),
810 // and append them into the vtable starting at index initialized,
811 // return the new value of initialized.
812 // Miranda methods use vtable entries, but do not get assigned a vtable_index
813 // The vtable_index is discovered by searching from the end of the vtable
814 int klassVtable::fill_in_mirandas(int initialized) {
815 GrowableArray<Method*> mirandas(20);
816 get_mirandas(&mirandas, NULL, ik()->super(), ik()->methods(),
817 ik()->default_methods(), ik()->local_interfaces());
818 for (int i = 0; i < mirandas.length(); i++) {
819 if (PrintVtables && Verbose) {
820 Method* meth = mirandas.at(i);
821 ResourceMark rm(Thread::current());
822 if (meth != NULL) {
823 char* sig = meth->name_and_sig_as_C_string();
824 tty->print("fill in mirandas with %s index %d, flags: ",
825 sig, initialized);
826 meth->access_flags().print_on(tty);
827 if (meth->is_default_method()) {
828 tty->print("default ");
829 }
830 tty->cr();
831 }
832 }
833 put_method_at(mirandas.at(i), initialized);
834 ++initialized;
835 }
836 return initialized;
837 }
838
839 // Copy this class's vtable to the vtable beginning at start.
840 // Used to copy superclass vtable to prefix of subclass's vtable.
841 void klassVtable::copy_vtable_to(vtableEntry* start) {
842 Copy::disjoint_words((HeapWord*)table(), (HeapWord*)start, _length * vtableEntry::size());
843 }
844
845 #if INCLUDE_JVMTI
846 bool klassVtable::adjust_default_method(int vtable_index, Method* old_method, Method* new_method) {
847 // If old_method is default, find this vtable index in default_vtable_indices
848 // and replace that method in the _default_methods list
849 bool updated = false;
850
851 Array<Method*>* default_methods = ik()->default_methods();
852 if (default_methods != NULL) {
853 int len = default_methods->length();
854 for (int idx = 0; idx < len; idx++) {
855 if (vtable_index == ik()->default_vtable_indices()->at(idx)) {
856 if (default_methods->at(idx) == old_method) {
857 default_methods->at_put(idx, new_method);
858 updated = true;
859 }
860 break;
861 }
862 }
863 }
864 return updated;
865 }
866
867 // search the vtable for uses of either obsolete or EMCP methods
868 void klassVtable::adjust_method_entries(InstanceKlass* holder, bool * trace_name_printed) {
869 int prn_enabled = 0;
870 for (int index = 0; index < length(); index++) {
871 Method* old_method = unchecked_method_at(index);
872 if (old_method == NULL || old_method->method_holder() != holder || !old_method->is_old()) {
873 continue; // skip uninteresting entries
874 }
875 assert(!old_method->is_deleted(), "vtable methods may not be deleted");
876
877 Method* new_method = holder->method_with_idnum(old_method->orig_method_idnum());
878
879 assert(new_method != NULL, "method_with_idnum() should not be NULL");
880 assert(old_method != new_method, "sanity check");
881
882 put_method_at(new_method, index);
883 // For default methods, need to update the _default_methods array
884 // which can only have one method entry for a given signature
885 bool updated_default = false;
886 if (old_method->is_default_method()) {
887 updated_default = adjust_default_method(index, old_method, new_method);
888 }
889
890 if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
891 if (!(*trace_name_printed)) {
892 // RC_TRACE_MESG macro has an embedded ResourceMark
893 RC_TRACE_MESG(("adjust: klassname=%s for methods from name=%s",
894 klass()->external_name(),
895 old_method->method_holder()->external_name()));
896 *trace_name_printed = true;
897 }
898 // RC_TRACE macro has an embedded ResourceMark
899 RC_TRACE(0x00100000, ("vtable method update: %s(%s), updated default = %s",
900 new_method->name()->as_C_string(),
901 new_method->signature()->as_C_string(),
902 updated_default ? "true" : "false"));
903 }
904 }
905 }
906
907 // a vtable should never contain old or obsolete methods
908 bool klassVtable::check_no_old_or_obsolete_entries() {
909 for (int i = 0; i < length(); i++) {
910 Method* m = unchecked_method_at(i);
911 if (m != NULL &&
912 (NOT_PRODUCT(!m->is_valid() ||) m->is_old() || m->is_obsolete())) {
913 return false;
914 }
915 }
916 return true;
917 }
918
919 void klassVtable::dump_vtable() {
920 tty->print_cr("vtable dump --");
921 for (int i = 0; i < length(); i++) {
922 Method* m = unchecked_method_at(i);
923 if (m != NULL) {
924 tty->print(" (%5d) ", i);
925 m->access_flags().print_on(tty);
926 if (m->is_default_method()) {
927 tty->print("default ");
928 }
929 if (m->is_overpass()) {
930 tty->print("overpass");
931 }
932 tty->print(" -- ");
933 m->print_name(tty);
934 tty->cr();
935 }
936 }
937 }
938 #endif // INCLUDE_JVMTI
939
940 // CDS/RedefineClasses support - clear vtables so they can be reinitialized
941 void klassVtable::clear_vtable() {
942 for (int i = 0; i < _length; i++) table()[i].clear();
943 }
944
945 bool klassVtable::is_initialized() {
946 return _length == 0 || table()[0].method() != NULL;
947 }
948
949 //-----------------------------------------------------------------------------------------
950 // Itable code
951
952 // Initialize a itableMethodEntry
953 void itableMethodEntry::initialize(Method* m) {
954 if (m == NULL) return;
955
956 _method = m;
957 }
958
959 klassItable::klassItable(instanceKlassHandle klass) {
960 _klass = klass;
961
962 if (klass->itable_length() > 0) {
963 itableOffsetEntry* offset_entry = (itableOffsetEntry*)klass->start_of_itable();
964 if (offset_entry != NULL && offset_entry->interface_klass() != NULL) { // Check that itable is initialized
965 // First offset entry points to the first method_entry
966 intptr_t* method_entry = (intptr_t *)(((address)klass()) + offset_entry->offset());
967 intptr_t* end = klass->end_of_itable();
968
969 _table_offset = (intptr_t*)offset_entry - (intptr_t*)klass();
970 _size_offset_table = (method_entry - ((intptr_t*)offset_entry)) / itableOffsetEntry::size();
971 _size_method_table = (end - method_entry) / itableMethodEntry::size();
972 assert(_table_offset >= 0 && _size_offset_table >= 0 && _size_method_table >= 0, "wrong computation");
973 return;
974 }
975 }
976
977 // The length of the itable was either zero, or it has not yet been initialized.
978 _table_offset = 0;
979 _size_offset_table = 0;
980 _size_method_table = 0;
981 }
982
983 static int initialize_count = 0;
984
985 // Initialization
986 void klassItable::initialize_itable(bool checkconstraints, TRAPS) {
987 if (_klass->is_interface()) {
988 // This needs to go after vtable indices are assigned but
989 // before implementors need to know the number of itable indices.
990 assign_itable_indices_for_interface(_klass());
991 }
992
993 // Cannot be setup doing bootstrapping, interfaces don't have
994 // itables, and klass with only ones entry have empty itables
995 if (Universe::is_bootstrapping() ||
996 _klass->is_interface() ||
997 _klass->itable_length() == itableOffsetEntry::size()) return;
998
999 // There's alway an extra itable entry so we can null-terminate it.
1000 guarantee(size_offset_table() >= 1, "too small");
1001 int num_interfaces = size_offset_table() - 1;
1002 if (num_interfaces > 0) {
1003 if (TraceItables) tty->print_cr("%3d: Initializing itables for %s", ++initialize_count,
1004 _klass->name()->as_C_string());
1005
1006
1007 // Iterate through all interfaces
1008 int i;
1009 for(i = 0; i < num_interfaces; i++) {
1010 itableOffsetEntry* ioe = offset_entry(i);
1011 HandleMark hm(THREAD);
1012 KlassHandle interf_h (THREAD, ioe->interface_klass());
1013 assert(interf_h() != NULL && ioe->offset() != 0, "bad offset entry in itable");
1014 initialize_itable_for_interface(ioe->offset(), interf_h, checkconstraints, CHECK);
1015 }
1016
1017 }
1018 // Check that the last entry is empty
1019 itableOffsetEntry* ioe = offset_entry(size_offset_table() - 1);
1020 guarantee(ioe->interface_klass() == NULL && ioe->offset() == 0, "terminator entry missing");
1021 }
1022
1023
1024 inline bool interface_method_needs_itable_index(Method* m) {
1025 if (m->is_static()) return false; // e.g., Stream.empty
1026 if (m->is_initializer()) return false; // <init> or <clinit>
1027 // If an interface redeclares a method from java.lang.Object,
1028 // it should already have a vtable index, don't touch it.
1029 // e.g., CharSequence.toString (from initialize_vtable)
1030 // if (m->has_vtable_index()) return false; // NO!
1031 return true;
1032 }
1033
1034 int klassItable::assign_itable_indices_for_interface(Klass* klass) {
1035 // an interface does not have an itable, but its methods need to be numbered
1036 if (TraceItables) tty->print_cr("%3d: Initializing itable indices for interface %s", ++initialize_count,
1037 klass->name()->as_C_string());
1038 Array<Method*>* methods = InstanceKlass::cast(klass)->methods();
1039 int nof_methods = methods->length();
1040 int ime_num = 0;
1041 for (int i = 0; i < nof_methods; i++) {
1042 Method* m = methods->at(i);
1043 if (interface_method_needs_itable_index(m)) {
1044 assert(!m->is_final_method(), "no final interface methods");
1045 // If m is already assigned a vtable index, do not disturb it.
1046 if (TraceItables && Verbose) {
1047 ResourceMark rm;
1048 const char* sig = (m != NULL) ? m->name_and_sig_as_C_string() : "<NULL>";
1049 if (m->has_vtable_index()) {
1050 tty->print("vtable index %d for method: %s, flags: ", m->vtable_index(), sig);
1051 } else {
1052 tty->print("itable index %d for method: %s, flags: ", ime_num, sig);
1053 }
1054 if (m != NULL) {
1055 m->access_flags().print_on(tty);
1056 if (m->is_default_method()) {
1057 tty->print("default ");
1058 }
1059 if (m->is_overpass()) {
1060 tty->print("overpass");
1061 }
1062 }
1063 tty->cr();
1064 }
1065 if (!m->has_vtable_index()) {
1066 assert(m->vtable_index() == Method::pending_itable_index, "set by initialize_vtable");
1067 m->set_itable_index(ime_num);
1068 // Progress to next itable entry
1069 ime_num++;
1070 }
1071 }
1072 }
1073 assert(ime_num == method_count_for_interface(klass), "proper sizing");
1074 return ime_num;
1075 }
1076
1077 int klassItable::method_count_for_interface(Klass* interf) {
1078 assert(interf->oop_is_instance(), "must be");
1079 assert(interf->is_interface(), "must be");
1080 Array<Method*>* methods = InstanceKlass::cast(interf)->methods();
1081 int nof_methods = methods->length();
1082 int length = 0;
1083 while (nof_methods > 0) {
1084 Method* m = methods->at(nof_methods-1);
1085 if (m->has_itable_index()) {
1086 length = m->itable_index() + 1;
1087 break;
1088 }
1089 nof_methods -= 1;
1090 }
1091 #ifdef ASSERT
1092 int nof_methods_copy = nof_methods;
1093 while (nof_methods_copy > 0) {
1094 Method* mm = methods->at(--nof_methods_copy);
1095 assert(!mm->has_itable_index() || mm->itable_index() < length, "");
1096 }
1097 #endif //ASSERT
1098 // return the rightmost itable index, plus one; or 0 if no methods have
1099 // itable indices
1100 return length;
1101 }
1102
1103
1104 void klassItable::initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS) {
1105 Array<Method*>* methods = InstanceKlass::cast(interf_h())->methods();
1106 int nof_methods = methods->length();
1107 HandleMark hm;
1108 assert(nof_methods > 0, "at least one method must exist for interface to be in vtable");
1109 Handle interface_loader (THREAD, InstanceKlass::cast(interf_h())->class_loader());
1110
1111 int ime_count = method_count_for_interface(interf_h());
1112 for (int i = 0; i < nof_methods; i++) {
1113 Method* m = methods->at(i);
1114 methodHandle target;
1115 if (m->has_itable_index()) {
1116 // This search must match the runtime resolution, i.e. selection search for invokeinterface
1117 // to correctly enforce loader constraints for interface method inheritance
1118 LinkResolver::lookup_instance_method_in_klasses(target, _klass, m->name(), m->signature(), CHECK);
1119 }
1120 if (target == NULL || !target->is_public() || target->is_abstract()) {
1121 // Entry does not resolve. Leave it empty for AbstractMethodError.
1122 if (!(target == NULL) && !target->is_public()) {
1123 // Stuff an IllegalAccessError throwing method in there instead.
1124 itableOffsetEntry::method_entry(_klass(), method_table_offset)[m->itable_index()].
1125 initialize(Universe::throw_illegal_access_error());
1126 }
1127 } else {
1128 // Entry did resolve, check loader constraints before initializing
1129 // if checkconstraints requested
1130 if (checkconstraints) {
1131 Handle method_holder_loader (THREAD, target->method_holder()->class_loader());
1132 if (method_holder_loader() != interface_loader()) {
1133 ResourceMark rm(THREAD);
1134 Symbol* failed_type_symbol =
1135 SystemDictionary::check_signature_loaders(m->signature(),
1136 method_holder_loader,
1137 interface_loader,
1138 true, CHECK);
1139 if (failed_type_symbol != NULL) {
1140 const char* msg = "loader constraint violation in interface "
1141 "itable initialization: when resolving method \"%s\" the class"
1142 " loader (instance of %s) of the current class, %s, "
1143 "and the class loader (instance of %s) for interface "
1144 "%s have different Class objects for the type %s "
1145 "used in the signature";
1146 char* sig = target()->name_and_sig_as_C_string();
1147 const char* loader1 = SystemDictionary::loader_name(method_holder_loader());
1148 char* current = _klass->name()->as_C_string();
1149 const char* loader2 = SystemDictionary::loader_name(interface_loader());
1150 char* iface = InstanceKlass::cast(interf_h())->name()->as_C_string();
1151 char* failed_type_name = failed_type_symbol->as_C_string();
1152 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
1153 strlen(current) + strlen(loader2) + strlen(iface) +
1154 strlen(failed_type_name);
1155 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
1156 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2,
1157 iface, failed_type_name);
1158 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
1159 }
1160 }
1161 }
1162
1163 // ime may have moved during GC so recalculate address
1164 int ime_num = m->itable_index();
1165 assert(ime_num < ime_count, "oob");
1166 itableOffsetEntry::method_entry(_klass(), method_table_offset)[ime_num].initialize(target());
1167 if (TraceItables && Verbose) {
1168 ResourceMark rm(THREAD);
1169 if (target() != NULL) {
1170 char* sig = target()->name_and_sig_as_C_string();
1171 tty->print("interface: %s, ime_num: %d, target: %s, method_holder: %s ",
1172 interf_h()->internal_name(), ime_num, sig,
1173 target()->method_holder()->internal_name());
1174 tty->print("target_method flags: ");
1175 target()->access_flags().print_on(tty);
1176 if (target()->is_default_method()) {
1177 tty->print("default ");
1178 }
1179 tty->cr();
1180 }
1181 }
1182 }
1183 }
1184 }
1185
1186 // Update entry for specific Method*
1187 void klassItable::initialize_with_method(Method* m) {
1188 itableMethodEntry* ime = method_entry(0);
1189 for(int i = 0; i < _size_method_table; i++) {
1190 if (ime->method() == m) {
1191 ime->initialize(m);
1192 }
1193 ime++;
1194 }
1195 }
1196
1197 #if INCLUDE_JVMTI
1198 // search the itable for uses of either obsolete or EMCP methods
1199 void klassItable::adjust_method_entries(InstanceKlass* holder, bool * trace_name_printed) {
1200
1201 itableMethodEntry* ime = method_entry(0);
1202 for (int i = 0; i < _size_method_table; i++, ime++) {
1203 Method* old_method = ime->method();
1204 if (old_method == NULL || old_method->method_holder() != holder || !old_method->is_old()) {
1205 continue; // skip uninteresting entries
1206 }
1207 assert(!old_method->is_deleted(), "itable methods may not be deleted");
1208
1209 Method* new_method = holder->method_with_idnum(old_method->orig_method_idnum());
1210
1211 assert(new_method != NULL, "method_with_idnum() should not be NULL");
1212 assert(old_method != new_method, "sanity check");
1213
1214 ime->initialize(new_method);
1215
1216 if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
1217 if (!(*trace_name_printed)) {
1218 // RC_TRACE_MESG macro has an embedded ResourceMark
1219 RC_TRACE_MESG(("adjust: name=%s",
1220 old_method->method_holder()->external_name()));
1221 *trace_name_printed = true;
1222 }
1223 // RC_TRACE macro has an embedded ResourceMark
1224 RC_TRACE(0x00200000, ("itable method update: %s(%s)",
1225 new_method->name()->as_C_string(),
1226 new_method->signature()->as_C_string()));
1227 }
1228 }
1229 }
1230
1231 // an itable should never contain old or obsolete methods
1232 bool klassItable::check_no_old_or_obsolete_entries() {
1233 itableMethodEntry* ime = method_entry(0);
1234 for (int i = 0; i < _size_method_table; i++) {
1235 Method* m = ime->method();
1236 if (m != NULL &&
1237 (NOT_PRODUCT(!m->is_valid() ||) m->is_old() || m->is_obsolete())) {
1238 return false;
1239 }
1240 ime++;
1241 }
1242 return true;
1243 }
1244
1245 void klassItable::dump_itable() {
1246 itableMethodEntry* ime = method_entry(0);
1247 tty->print_cr("itable dump --");
1248 for (int i = 0; i < _size_method_table; i++) {
1249 Method* m = ime->method();
1250 if (m != NULL) {
1251 tty->print(" (%5d) ", i);
1252 m->access_flags().print_on(tty);
1253 if (m->is_default_method()) {
1254 tty->print("default ");
1255 }
1256 tty->print(" -- ");
1257 m->print_name(tty);
1258 tty->cr();
1259 }
1260 ime++;
1261 }
1262 }
1263 #endif // INCLUDE_JVMTI
1264
1265
1266 // Setup
1267 class InterfaceVisiterClosure : public StackObj {
1268 public:
1269 virtual void doit(Klass* intf, int method_count) = 0;
1270 };
1271
1272 // Visit all interfaces with at least one itable method
1273 void visit_all_interfaces(Array<Klass*>* transitive_intf, InterfaceVisiterClosure *blk) {
1274 // Handle array argument
1275 for(int i = 0; i < transitive_intf->length(); i++) {
1276 Klass* intf = transitive_intf->at(i);
1277 assert(intf->is_interface(), "sanity check");
1278
1279 // Find no. of itable methods
1280 int method_count = 0;
1281 // method_count = klassItable::method_count_for_interface(intf);
1282 Array<Method*>* methods = InstanceKlass::cast(intf)->methods();
1283 if (methods->length() > 0) {
1284 for (int i = methods->length(); --i >= 0; ) {
1285 if (interface_method_needs_itable_index(methods->at(i))) {
1286 method_count++;
1287 }
1288 }
1289 }
1290
1291 // Only count interfaces with at least one method
1292 if (method_count > 0) {
1293 blk->doit(intf, method_count);
1294 }
1295 }
1296 }
1297
1298 class CountInterfacesClosure : public InterfaceVisiterClosure {
1299 private:
1300 int _nof_methods;
1301 int _nof_interfaces;
1302 public:
1303 CountInterfacesClosure() { _nof_methods = 0; _nof_interfaces = 0; }
1304
1305 int nof_methods() const { return _nof_methods; }
1306 int nof_interfaces() const { return _nof_interfaces; }
1307
1308 void doit(Klass* intf, int method_count) { _nof_methods += method_count; _nof_interfaces++; }
1309 };
1310
1311 class SetupItableClosure : public InterfaceVisiterClosure {
1312 private:
1313 itableOffsetEntry* _offset_entry;
1314 itableMethodEntry* _method_entry;
1315 address _klass_begin;
1316 public:
1317 SetupItableClosure(address klass_begin, itableOffsetEntry* offset_entry, itableMethodEntry* method_entry) {
1318 _klass_begin = klass_begin;
1319 _offset_entry = offset_entry;
1320 _method_entry = method_entry;
1321 }
1322
1323 itableMethodEntry* method_entry() const { return _method_entry; }
1324
1325 void doit(Klass* intf, int method_count) {
1326 int offset = ((address)_method_entry) - _klass_begin;
1327 _offset_entry->initialize(intf, offset);
1328 _offset_entry++;
1329 _method_entry += method_count;
1330 }
1331 };
1332
1333 int klassItable::compute_itable_size(Array<Klass*>* transitive_interfaces) {
1334 // Count no of interfaces and total number of interface methods
1335 CountInterfacesClosure cic;
1336 visit_all_interfaces(transitive_interfaces, &cic);
1337
1338 // There's alway an extra itable entry so we can null-terminate it.
1339 int itable_size = calc_itable_size(cic.nof_interfaces() + 1, cic.nof_methods());
1340
1341 // Statistics
1342 update_stats(itable_size * HeapWordSize);
1343
1344 return itable_size;
1345 }
1346
1347
1348 // Fill out offset table and interface klasses into the itable space
1349 void klassItable::setup_itable_offset_table(instanceKlassHandle klass) {
1350 if (klass->itable_length() == 0) return;
1351 assert(!klass->is_interface(), "Should have zero length itable");
1352
1353 // Count no of interfaces and total number of interface methods
1354 CountInterfacesClosure cic;
1355 visit_all_interfaces(klass->transitive_interfaces(), &cic);
1356 int nof_methods = cic.nof_methods();
1357 int nof_interfaces = cic.nof_interfaces();
1358
1359 // Add one extra entry so we can null-terminate the table
1360 nof_interfaces++;
1361
1362 assert(compute_itable_size(klass->transitive_interfaces()) ==
1363 calc_itable_size(nof_interfaces, nof_methods),
1364 "mismatch calculation of itable size");
1365
1366 // Fill-out offset table
1367 itableOffsetEntry* ioe = (itableOffsetEntry*)klass->start_of_itable();
1368 itableMethodEntry* ime = (itableMethodEntry*)(ioe + nof_interfaces);
1369 intptr_t* end = klass->end_of_itable();
1370 assert((oop*)(ime + nof_methods) <= (oop*)klass->start_of_nonstatic_oop_maps(), "wrong offset calculation (1)");
1371 assert((oop*)(end) == (oop*)(ime + nof_methods), "wrong offset calculation (2)");
1372
1373 // Visit all interfaces and initialize itable offset table
1374 SetupItableClosure sic((address)klass(), ioe, ime);
1375 visit_all_interfaces(klass->transitive_interfaces(), &sic);
1376
1377 #ifdef ASSERT
1378 ime = sic.method_entry();
1379 oop* v = (oop*) klass->end_of_itable();
1380 assert( (oop*)(ime) == v, "wrong offset calculation (2)");
1381 #endif
1382 }
1383
1384
1385 // inverse to itable_index
1386 Method* klassItable::method_for_itable_index(Klass* intf, int itable_index) {
1387 assert(InstanceKlass::cast(intf)->is_interface(), "sanity check");
1388 assert(intf->verify_itable_index(itable_index), "");
1389 Array<Method*>* methods = InstanceKlass::cast(intf)->methods();
1390
1391 if (itable_index < 0 || itable_index >= method_count_for_interface(intf))
1392 return NULL; // help caller defend against bad indices
1393
1394 int index = itable_index;
1395 Method* m = methods->at(index);
1396 int index2 = -1;
1397 while (!m->has_itable_index() ||
1398 (index2 = m->itable_index()) != itable_index) {
1399 assert(index2 < itable_index, "monotonic");
1400 if (++index == methods->length())
1401 return NULL;
1402 m = methods->at(index);
1403 }
1404 assert(m->itable_index() == itable_index, "correct inverse");
1405
1406 return m;
1407 }
1408
1409 void klassVtable::verify(outputStream* st, bool forced) {
1410 // make sure table is initialized
1411 if (!Universe::is_fully_initialized()) return;
1412 #ifndef PRODUCT
1413 // avoid redundant verifies
1414 if (!forced && _verify_count == Universe::verify_count()) return;
1415 _verify_count = Universe::verify_count();
1416 #endif
1417 oop* end_of_obj = (oop*)_klass() + _klass()->size();
1418 oop* end_of_vtable = (oop *)&table()[_length];
1419 if (end_of_vtable > end_of_obj) {
1420 fatal(err_msg("klass %s: klass object too short (vtable extends beyond "
1421 "end)", _klass->internal_name()));
1422 }
1423
1424 for (int i = 0; i < _length; i++) table()[i].verify(this, st);
1425 // verify consistency with superKlass vtable
1426 Klass* super = _klass->super();
1427 if (super != NULL) {
1428 InstanceKlass* sk = InstanceKlass::cast(super);
1429 klassVtable* vt = sk->vtable();
1430 for (int i = 0; i < vt->length(); i++) {
1431 verify_against(st, vt, i);
1432 }
1433 }
1434 }
1435
1436 void klassVtable::verify_against(outputStream* st, klassVtable* vt, int index) {
1437 vtableEntry* vte = &vt->table()[index];
1438 if (vte->method()->name() != table()[index].method()->name() ||
1439 vte->method()->signature() != table()[index].method()->signature()) {
1440 fatal("mismatched name/signature of vtable entries");
1441 }
1442 }
1443
1444 #ifndef PRODUCT
1445 void klassVtable::print() {
1446 ResourceMark rm;
1447 tty->print("klassVtable for klass %s (length %d):\n", _klass->internal_name(), length());
1448 for (int i = 0; i < length(); i++) {
1449 table()[i].print();
1450 tty->cr();
1451 }
1452 }
1453 #endif
1454
1455 void vtableEntry::verify(klassVtable* vt, outputStream* st) {
1456 NOT_PRODUCT(FlagSetting fs(IgnoreLockingAssertions, true));
1457 assert(method() != NULL, "must have set method");
1458 method()->verify();
1459 // we sub_type, because it could be a miranda method
1460 if (!vt->klass()->is_subtype_of(method()->method_holder())) {
1461 #ifndef PRODUCT
1462 print();
1463 #endif
1464 fatal(err_msg("vtableEntry " PTR_FORMAT ": method is from subclass", this));
1465 }
1466 }
1467
1468 #ifndef PRODUCT
1469
1470 void vtableEntry::print() {
1471 ResourceMark rm;
1472 tty->print("vtableEntry %s: ", method()->name()->as_C_string());
1473 if (Verbose) {
1474 tty->print("m %#lx ", (address)method());
1475 }
1476 }
1477
1478 class VtableStats : AllStatic {
1479 public:
1480 static int no_klasses; // # classes with vtables
1481 static int no_array_klasses; // # array classes
1482 static int no_instance_klasses; // # instanceKlasses
1483 static int sum_of_vtable_len; // total # of vtable entries
1484 static int sum_of_array_vtable_len; // total # of vtable entries in array klasses only
1485 static int fixed; // total fixed overhead in bytes
1486 static int filler; // overhead caused by filler bytes
1487 static int entries; // total bytes consumed by vtable entries
1488 static int array_entries; // total bytes consumed by array vtable entries
1489
1490 static void do_class(Klass* k) {
1491 Klass* kl = k;
1492 klassVtable* vt = kl->vtable();
1493 if (vt == NULL) return;
1494 no_klasses++;
1495 if (kl->oop_is_instance()) {
1496 no_instance_klasses++;
1497 kl->array_klasses_do(do_class);
1498 }
1499 if (kl->oop_is_array()) {
1500 no_array_klasses++;
1501 sum_of_array_vtable_len += vt->length();
1502 }
1503 sum_of_vtable_len += vt->length();
1504 }
1505
1506 static void compute() {
1507 SystemDictionary::classes_do(do_class);
1508 fixed = no_klasses * oopSize; // vtable length
1509 // filler size is a conservative approximation
1510 filler = oopSize * (no_klasses - no_instance_klasses) * (sizeof(InstanceKlass) - sizeof(ArrayKlass) - 1);
1511 entries = sizeof(vtableEntry) * sum_of_vtable_len;
1512 array_entries = sizeof(vtableEntry) * sum_of_array_vtable_len;
1513 }
1514 };
1515
1516 int VtableStats::no_klasses = 0;
1517 int VtableStats::no_array_klasses = 0;
1518 int VtableStats::no_instance_klasses = 0;
1519 int VtableStats::sum_of_vtable_len = 0;
1520 int VtableStats::sum_of_array_vtable_len = 0;
1521 int VtableStats::fixed = 0;
1522 int VtableStats::filler = 0;
1523 int VtableStats::entries = 0;
1524 int VtableStats::array_entries = 0;
1525
1526 void klassVtable::print_statistics() {
1527 ResourceMark rm;
1528 HandleMark hm;
1529 VtableStats::compute();
1530 tty->print_cr("vtable statistics:");
1531 tty->print_cr("%6d classes (%d instance, %d array)", VtableStats::no_klasses, VtableStats::no_instance_klasses, VtableStats::no_array_klasses);
1532 int total = VtableStats::fixed + VtableStats::filler + VtableStats::entries;
1533 tty->print_cr("%6d bytes fixed overhead (refs + vtable object header)", VtableStats::fixed);
1534 tty->print_cr("%6d bytes filler overhead", VtableStats::filler);
1535 tty->print_cr("%6d bytes for vtable entries (%d for arrays)", VtableStats::entries, VtableStats::array_entries);
1536 tty->print_cr("%6d bytes total", total);
1537 }
1538
1539 int klassItable::_total_classes; // Total no. of classes with itables
1540 long klassItable::_total_size; // Total no. of bytes used for itables
1541
1542 void klassItable::print_statistics() {
1543 tty->print_cr("itable statistics:");
1544 tty->print_cr("%6d classes with itables", _total_classes);
1545 tty->print_cr("%6d K uses for itables (average by class: %d bytes)", _total_size / K, _total_size / _total_classes);
1546 }
1547
1548 #endif // PRODUCT