1 /*
2 * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/systemDictionary.hpp"
27 #include "classfile/vmSymbols.hpp"
28 #include "gc/shared/gcLocker.hpp"
29 #include "memory/resourceArea.hpp"
30 #include "memory/universe.inline.hpp"
31 #include "oops/instanceKlass.hpp"
32 #include "oops/klassVtable.hpp"
33 #include "oops/method.hpp"
34 #include "oops/objArrayOop.hpp"
35 #include "oops/oop.inline.hpp"
36 #include "prims/jvmtiRedefineClassesTrace.hpp"
37 #include "runtime/arguments.hpp"
38 #include "runtime/handles.inline.hpp"
39 #include "utilities/copy.hpp"
40
41 inline InstanceKlass* klassVtable::ik() const {
42 return InstanceKlass::cast(_klass());
43 }
44
45
46 // this function computes the vtable size (including the size needed for miranda
47 // methods) and the number of miranda methods in this class.
48 // Note on Miranda methods: Let's say there is a class C that implements
49 // interface I, and none of C's superclasses implements I.
50 // Let's say there is an abstract method m in I that neither C
51 // nor any of its super classes implement (i.e there is no method of any access,
52 // with the same name and signature as m), then m is a Miranda method which is
53 // entered as a public abstract method in C's vtable. From then on it should
54 // treated as any other public method in C for method over-ride purposes.
55 void klassVtable::compute_vtable_size_and_num_mirandas(
56 int* vtable_length_ret, int* num_new_mirandas,
57 GrowableArray<Method*>* all_mirandas, Klass* super,
58 Array<Method*>* methods, AccessFlags class_flags,
59 Handle classloader, Symbol* classname, Array<Klass*>* local_interfaces,
60 TRAPS) {
61 No_Safepoint_Verifier nsv;
62
63 // set up default result values
64 int vtable_length = 0;
65
66 // start off with super's vtable length
67 vtable_length = super == NULL ? 0 : super->vtable_length();
68
69 // go thru each method in the methods table to see if it needs a new entry
70 int len = methods->length();
71 for (int i = 0; i < len; i++) {
72 assert(methods->at(i)->is_method(), "must be a Method*");
73 methodHandle mh(THREAD, methods->at(i));
74
75 if (needs_new_vtable_entry(mh, super, classloader, classname, class_flags, THREAD)) {
76 vtable_length += vtableEntry::size(); // we need a new entry
77 }
78 }
79
80 GrowableArray<Method*> new_mirandas(20);
81 // compute the number of mirandas methods that must be added to the end
82 get_mirandas(&new_mirandas, all_mirandas, super, methods, NULL, local_interfaces);
83 *num_new_mirandas = new_mirandas.length();
84
85 // Interfaces do not need interface methods in their vtables
86 // This includes miranda methods and during later processing, default methods
87 if (!class_flags.is_interface()) {
88 vtable_length += *num_new_mirandas * vtableEntry::size();
89 }
90
91 if (Universe::is_bootstrapping() && vtable_length == 0) {
92 // array classes don't have their superclass set correctly during
93 // bootstrapping
94 vtable_length = Universe::base_vtable_size();
95 }
96
97 if (super == NULL && vtable_length != Universe::base_vtable_size()) {
98 if (Universe::is_bootstrapping()) {
99 // Someone is attempting to override java.lang.Object incorrectly on the
100 // bootclasspath. The JVM cannot recover from this error including throwing
101 // an exception
102 vm_exit_during_initialization("Incompatible definition of java.lang.Object");
103 } else {
104 // Someone is attempting to redefine java.lang.Object incorrectly. The
105 // only way this should happen is from
106 // SystemDictionary::resolve_from_stream(), which will detect this later
107 // and throw a security exception. So don't assert here to let
108 // the exception occur.
109 vtable_length = Universe::base_vtable_size();
110 }
111 }
112 assert(vtable_length % vtableEntry::size() == 0, "bad vtable length");
113 assert(vtable_length >= Universe::base_vtable_size(), "vtable too small");
114
115 *vtable_length_ret = vtable_length;
116 }
117
118 int klassVtable::index_of(Method* m, int len) const {
119 assert(m->has_vtable_index(), "do not ask this of non-vtable methods");
120 return m->vtable_index();
121 }
122
123 // Copy super class's vtable to the first part (prefix) of this class's vtable,
124 // and return the number of entries copied. Expects that 'super' is the Java
125 // super class (arrays can have "array" super classes that must be skipped).
126 int klassVtable::initialize_from_super(KlassHandle super) {
127 if (super.is_null()) {
128 return 0;
129 } else {
130 // copy methods from superKlass
131 klassVtable* superVtable = super->vtable();
132 assert(superVtable->length() <= _length, "vtable too short");
133 #ifdef ASSERT
134 superVtable->verify(tty, true);
135 #endif
136 superVtable->copy_vtable_to(table());
137 #ifndef PRODUCT
138 if (PrintVtables && Verbose) {
139 ResourceMark rm;
140 tty->print_cr("copy vtable from %s to %s size %d", super->internal_name(), klass()->internal_name(), _length);
141 }
142 #endif
143 return superVtable->length();
144 }
145 }
146
147 //
148 // Revised lookup semantics introduced 1.3 (Kestrel beta)
149 void klassVtable::initialize_vtable(bool checkconstraints, TRAPS) {
150
151 // Note: Arrays can have intermediate array supers. Use java_super to skip them.
152 KlassHandle super (THREAD, klass()->java_super());
153 int nofNewEntries = 0;
154
155 if (PrintVtables && !klass()->is_array_klass()) {
156 ResourceMark rm(THREAD);
157 tty->print_cr("Initializing: %s", _klass->name()->as_C_string());
158 }
159
160 #ifdef ASSERT
161 oop* end_of_obj = (oop*)_klass() + _klass()->size();
162 oop* end_of_vtable = (oop*)&table()[_length];
163 assert(end_of_vtable <= end_of_obj, "vtable extends beyond end");
164 #endif
165
166 if (Universe::is_bootstrapping()) {
167 // just clear everything
168 for (int i = 0; i < _length; i++) table()[i].clear();
169 return;
170 }
171
172 int super_vtable_len = initialize_from_super(super);
173 if (klass()->is_array_klass()) {
174 assert(super_vtable_len == _length, "arrays shouldn't introduce new methods");
175 } else {
176 assert(_klass->is_instance_klass(), "must be InstanceKlass");
177
178 Array<Method*>* methods = ik()->methods();
179 int len = methods->length();
180 int initialized = super_vtable_len;
181
182 // Check each of this class's methods against super;
183 // if override, replace in copy of super vtable, otherwise append to end
184 for (int i = 0; i < len; i++) {
185 // update_inherited_vtable can stop for gc - ensure using handles
186 HandleMark hm(THREAD);
187 assert(methods->at(i)->is_method(), "must be a Method*");
188 methodHandle mh(THREAD, methods->at(i));
189
190 bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, -1, checkconstraints, CHECK);
191
192 if (needs_new_entry) {
193 put_method_at(mh(), initialized);
194 mh()->set_vtable_index(initialized); // set primary vtable index
195 initialized++;
196 }
197 }
198
199 // update vtable with default_methods
200 Array<Method*>* default_methods = ik()->default_methods();
201 if (default_methods != NULL) {
202 len = default_methods->length();
203 if (len > 0) {
204 Array<int>* def_vtable_indices = NULL;
205 if ((def_vtable_indices = ik()->default_vtable_indices()) == NULL) {
206 def_vtable_indices = ik()->create_new_default_vtable_indices(len, CHECK);
207 } else {
208 assert(def_vtable_indices->length() == len, "reinit vtable len?");
209 }
210 for (int i = 0; i < len; i++) {
211 HandleMark hm(THREAD);
212 assert(default_methods->at(i)->is_method(), "must be a Method*");
213 methodHandle mh(THREAD, default_methods->at(i));
214
215 bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, i, checkconstraints, CHECK);
216
217 // needs new entry
218 if (needs_new_entry) {
219 put_method_at(mh(), initialized);
220 def_vtable_indices->at_put(i, initialized); //set vtable index
221 initialized++;
222 }
223 }
224 }
225 }
226
227 // add miranda methods; it will also return the updated initialized
228 // Interfaces do not need interface methods in their vtables
229 // This includes miranda methods and during later processing, default methods
230 if (!ik()->is_interface()) {
231 initialized = fill_in_mirandas(initialized);
232 }
233
234 // In class hierarchies where the accessibility is not increasing (i.e., going from private ->
235 // package_private -> public/protected), the vtable might actually be smaller than our initial
236 // calculation.
237 assert(initialized <= _length, "vtable initialization failed");
238 for(;initialized < _length; initialized++) {
239 put_method_at(NULL, initialized);
240 }
241 NOT_PRODUCT(verify(tty, true));
242 }
243 }
244
245 // Called for cases where a method does not override its superclass' vtable entry
246 // For bytecodes not produced by javac together it is possible that a method does not override
247 // the superclass's method, but might indirectly override a super-super class's vtable entry
248 // If none found, return a null superk, else return the superk of the method this does override
249 // For public and protected methods: if they override a superclass, they will
250 // also be overridden themselves appropriately.
251 // Private methods do not override and are not overridden.
252 // Package Private methods are trickier:
253 // e.g. P1.A, pub m
254 // P2.B extends A, package private m
255 // P1.C extends B, public m
256 // P1.C.m needs to override P1.A.m and can not override P2.B.m
257 // Therefore: all package private methods need their own vtable entries for
258 // them to be the root of an inheritance overriding decision
259 // Package private methods may also override other vtable entries
260 InstanceKlass* klassVtable::find_transitive_override(InstanceKlass* initialsuper, methodHandle target_method,
261 int vtable_index, Handle target_loader, Symbol* target_classname, Thread * THREAD) {
262 InstanceKlass* superk = initialsuper;
263 while (superk != NULL && superk->super() != NULL) {
264 InstanceKlass* supersuperklass = InstanceKlass::cast(superk->super());
265 klassVtable* ssVtable = supersuperklass->vtable();
266 if (vtable_index < ssVtable->length()) {
267 Method* super_method = ssVtable->method_at(vtable_index);
268 #ifndef PRODUCT
269 Symbol* name= target_method()->name();
270 Symbol* signature = target_method()->signature();
271 assert(super_method->name() == name && super_method->signature() == signature, "vtable entry name/sig mismatch");
272 #endif
273 if (supersuperklass->is_override(super_method, target_loader, target_classname, THREAD)) {
274 #ifndef PRODUCT
275 if (PrintVtables && Verbose) {
276 ResourceMark rm(THREAD);
277 char* sig = target_method()->name_and_sig_as_C_string();
278 tty->print("transitive overriding superclass %s with %s::%s index %d, original flags: ",
279 supersuperklass->internal_name(),
280 _klass->internal_name(), sig, vtable_index);
281 super_method->access_flags().print_on(tty);
282 if (super_method->is_default_method()) {
283 tty->print("default ");
284 }
285 tty->print("overriders flags: ");
286 target_method->access_flags().print_on(tty);
287 if (target_method->is_default_method()) {
288 tty->print("default ");
289 }
290 }
291 #endif /*PRODUCT*/
292 break; // return found superk
293 }
294 } else {
295 // super class has no vtable entry here, stop transitive search
296 superk = (InstanceKlass*)NULL;
297 break;
298 }
299 // if no override found yet, continue to search up
300 superk = superk->super() == NULL ? NULL : InstanceKlass::cast(superk->super());
301 }
302
303 return superk;
304 }
305
306 // Update child's copy of super vtable for overrides
307 // OR return true if a new vtable entry is required.
308 // Only called for InstanceKlass's, i.e. not for arrays
309 // If that changed, could not use _klass as handle for klass
310 bool klassVtable::update_inherited_vtable(InstanceKlass* klass, methodHandle target_method,
311 int super_vtable_len, int default_index,
312 bool checkconstraints, TRAPS) {
313 ResourceMark rm;
314 bool allocate_new = true;
315 assert(klass->is_instance_klass(), "must be InstanceKlass");
316
317 Array<int>* def_vtable_indices = NULL;
318 bool is_default = false;
319 // default methods are concrete methods in superinterfaces which are added to the vtable
320 // with their real method_holder
321 // Since vtable and itable indices share the same storage, don't touch
322 // the default method's real vtable/itable index
323 // default_vtable_indices stores the vtable value relative to this inheritor
324 if (default_index >= 0 ) {
325 is_default = true;
326 def_vtable_indices = klass->default_vtable_indices();
327 assert(def_vtable_indices != NULL, "def vtable alloc?");
328 assert(default_index <= def_vtable_indices->length(), "def vtable len?");
329 } else {
330 assert(klass == target_method()->method_holder(), "caller resp.");
331 // Initialize the method's vtable index to "nonvirtual".
332 // If we allocate a vtable entry, we will update it to a non-negative number.
333 target_method()->set_vtable_index(Method::nonvirtual_vtable_index);
334 }
335
336 // Static and <init> methods are never in
337 if (target_method()->is_static() || target_method()->name() == vmSymbols::object_initializer_name()) {
338 return false;
339 }
340
341 if (target_method->is_final_method(klass->access_flags())) {
342 // a final method never needs a new entry; final methods can be statically
343 // resolved and they have to be present in the vtable only if they override
344 // a super's method, in which case they re-use its entry
345 allocate_new = false;
346 } else if (klass->is_interface()) {
347 allocate_new = false; // see note below in needs_new_vtable_entry
348 // An interface never allocates new vtable slots, only inherits old ones.
349 // This method will either be assigned its own itable index later,
350 // or be assigned an inherited vtable index in the loop below.
351 // default methods inherited by classes store their vtable indices
352 // in the inheritor's default_vtable_indices
353 // default methods inherited by interfaces may already have a
354 // valid itable index, if so, don't change it
355 // overpass methods in an interface will be assigned an itable index later
356 // by an inheriting class
357 if (!is_default || !target_method()->has_itable_index()) {
358 target_method()->set_vtable_index(Method::pending_itable_index);
359 }
360 }
361
362 // we need a new entry if there is no superclass
363 if (klass->super() == NULL) {
364 return allocate_new;
365 }
366
367 // private methods in classes always have a new entry in the vtable
368 // specification interpretation since classic has
369 // private methods not overriding
370 // JDK8 adds private methods in interfaces which require invokespecial
371 if (target_method()->is_private()) {
372 return allocate_new;
373 }
374
375 // search through the vtable and update overridden entries
376 // Since check_signature_loaders acquires SystemDictionary_lock
377 // which can block for gc, once we are in this loop, use handles
378 // For classfiles built with >= jdk7, we now look for transitive overrides
379
380 Symbol* name = target_method()->name();
381 Symbol* signature = target_method()->signature();
382
383 KlassHandle target_klass(THREAD, target_method()->method_holder());
384 if (target_klass == NULL) {
385 target_klass = _klass;
386 }
387
388 Handle target_loader(THREAD, target_klass->class_loader());
389
390 Symbol* target_classname = target_klass->name();
391 for(int i = 0; i < super_vtable_len; i++) {
392 Method* super_method = method_at(i);
393 // Check if method name matches
394 if (super_method->name() == name && super_method->signature() == signature) {
395
396 // get super_klass for method_holder for the found method
397 InstanceKlass* super_klass = super_method->method_holder();
398
399 // private methods are also never overridden
400 if (!super_method->is_private() &&
401 (is_default
402 || ((super_klass->is_override(super_method, target_loader, target_classname, THREAD))
403 || ((klass->major_version() >= VTABLE_TRANSITIVE_OVERRIDE_VERSION)
404 && ((super_klass = find_transitive_override(super_klass,
405 target_method, i, target_loader,
406 target_classname, THREAD))
407 != (InstanceKlass*)NULL)))))
408 {
409 // Package private methods always need a new entry to root their own
410 // overriding. They may also override other methods.
411 if (!target_method()->is_package_private()) {
412 allocate_new = false;
413 }
414
415 if (checkconstraints) {
416 // Override vtable entry if passes loader constraint check
417 // if loader constraint checking requested
418 // No need to visit his super, since he and his super
419 // have already made any needed loader constraints.
420 // Since loader constraints are transitive, it is enough
421 // to link to the first super, and we get all the others.
422 Handle super_loader(THREAD, super_klass->class_loader());
423
424 if (target_loader() != super_loader()) {
425 ResourceMark rm(THREAD);
426 Symbol* failed_type_symbol =
427 SystemDictionary::check_signature_loaders(signature, target_loader,
428 super_loader, true,
429 CHECK_(false));
430 if (failed_type_symbol != NULL) {
431 const char* msg = "loader constraint violation: when resolving "
432 "overridden method \"%s\" the class loader (instance"
433 " of %s) of the current class, %s, and its superclass loader "
434 "(instance of %s), have different Class objects for the type "
435 "%s used in the signature";
436 char* sig = target_method()->name_and_sig_as_C_string();
437 const char* loader1 = SystemDictionary::loader_name(target_loader());
438 char* current = target_klass->name()->as_C_string();
439 const char* loader2 = SystemDictionary::loader_name(super_loader());
440 char* failed_type_name = failed_type_symbol->as_C_string();
441 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
442 strlen(current) + strlen(loader2) + strlen(failed_type_name);
443 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
444 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2,
445 failed_type_name);
446 THROW_MSG_(vmSymbols::java_lang_LinkageError(), buf, false);
447 }
448 }
449 }
450
451 put_method_at(target_method(), i);
452 if (!is_default) {
453 target_method()->set_vtable_index(i);
454 } else {
455 if (def_vtable_indices != NULL) {
456 def_vtable_indices->at_put(default_index, i);
457 }
458 assert(super_method->is_default_method() || super_method->is_overpass()
459 || super_method->is_abstract(), "default override error");
460 }
461
462
463 #ifndef PRODUCT
464 if (PrintVtables && Verbose) {
465 ResourceMark rm(THREAD);
466 char* sig = target_method()->name_and_sig_as_C_string();
467 tty->print("overriding with %s::%s index %d, original flags: ",
468 target_klass->internal_name(), sig, i);
469 super_method->access_flags().print_on(tty);
470 if (super_method->is_default_method()) {
471 tty->print("default ");
472 }
473 if (super_method->is_overpass()) {
474 tty->print("overpass");
475 }
476 tty->print("overriders flags: ");
477 target_method->access_flags().print_on(tty);
478 if (target_method->is_default_method()) {
479 tty->print("default ");
480 }
481 if (target_method->is_overpass()) {
482 tty->print("overpass");
483 }
484 tty->cr();
485 }
486 #endif /*PRODUCT*/
487 } else {
488 // allocate_new = true; default. We might override one entry,
489 // but not override another. Once we override one, not need new
490 #ifndef PRODUCT
491 if (PrintVtables && Verbose) {
492 ResourceMark rm(THREAD);
493 char* sig = target_method()->name_and_sig_as_C_string();
494 tty->print("NOT overriding with %s::%s index %d, original flags: ",
495 target_klass->internal_name(), sig,i);
496 super_method->access_flags().print_on(tty);
497 if (super_method->is_default_method()) {
498 tty->print("default ");
499 }
500 if (super_method->is_overpass()) {
501 tty->print("overpass");
502 }
503 tty->print("overriders flags: ");
504 target_method->access_flags().print_on(tty);
505 if (target_method->is_default_method()) {
506 tty->print("default ");
507 }
508 if (target_method->is_overpass()) {
509 tty->print("overpass");
510 }
511 tty->cr();
512 }
513 #endif /*PRODUCT*/
514 }
515 }
516 }
517 return allocate_new;
518 }
519
520 void klassVtable::put_method_at(Method* m, int index) {
521 #ifndef PRODUCT
522 if (PrintVtables && Verbose) {
523 ResourceMark rm;
524 const char* sig = (m != NULL) ? m->name_and_sig_as_C_string() : "<NULL>";
525 tty->print("adding %s at index %d, flags: ", sig, index);
526 if (m != NULL) {
527 m->access_flags().print_on(tty);
528 if (m->is_default_method()) {
529 tty->print("default ");
530 }
531 if (m->is_overpass()) {
532 tty->print("overpass");
533 }
534 }
535 tty->cr();
536 }
537 #endif
538 table()[index].set(m);
539 }
540
541 // Find out if a method "m" with superclass "super", loader "classloader" and
542 // name "classname" needs a new vtable entry. Let P be a class package defined
543 // by "classloader" and "classname".
544 // NOTE: The logic used here is very similar to the one used for computing
545 // the vtables indices for a method. We cannot directly use that function because,
546 // we allocate the InstanceKlass at load time, and that requires that the
547 // superclass has been loaded.
548 // However, the vtable entries are filled in at link time, and therefore
549 // the superclass' vtable may not yet have been filled in.
550 bool klassVtable::needs_new_vtable_entry(methodHandle target_method,
551 Klass* super,
552 Handle classloader,
553 Symbol* classname,
554 AccessFlags class_flags,
555 TRAPS) {
556 if (class_flags.is_interface()) {
557 // Interfaces do not use vtables, except for java.lang.Object methods,
558 // so there is no point to assigning
559 // a vtable index to any of their local methods. If we refrain from doing this,
560 // we can use Method::_vtable_index to hold the itable index
561 return false;
562 }
563
564 if (target_method->is_final_method(class_flags) ||
565 // a final method never needs a new entry; final methods can be statically
566 // resolved and they have to be present in the vtable only if they override
567 // a super's method, in which case they re-use its entry
568 (target_method()->is_static()) ||
569 // static methods don't need to be in vtable
570 (target_method()->name() == vmSymbols::object_initializer_name())
571 // <init> is never called dynamically-bound
572 ) {
573 return false;
574 }
575
576 // Concrete interface methods do not need new entries, they override
577 // abstract method entries using default inheritance rules
578 if (target_method()->method_holder() != NULL &&
579 target_method()->method_holder()->is_interface() &&
580 !target_method()->is_abstract() ) {
581 return false;
582 }
583
584 // we need a new entry if there is no superclass
585 if (super == NULL) {
586 return true;
587 }
588
589 // private methods in classes always have a new entry in the vtable
590 // specification interpretation since classic has
591 // private methods not overriding
592 // JDK8 adds private methods in interfaces which require invokespecial
593 if (target_method()->is_private()) {
594 return true;
595 }
596
597 // Package private methods always need a new entry to root their own
598 // overriding. This allows transitive overriding to work.
599 if (target_method()->is_package_private()) {
600 return true;
601 }
602
603 // search through the super class hierarchy to see if we need
604 // a new entry
605 ResourceMark rm;
606 Symbol* name = target_method()->name();
607 Symbol* signature = target_method()->signature();
608 Klass* k = super;
609 Method* super_method = NULL;
610 InstanceKlass *holder = NULL;
611 Method* recheck_method = NULL;
612 while (k != NULL) {
613 // lookup through the hierarchy for a method with matching name and sign.
614 super_method = InstanceKlass::cast(k)->lookup_method(name, signature);
615 if (super_method == NULL) {
616 break; // we still have to search for a matching miranda method
617 }
618 // get the class holding the matching method
619 // make sure you use that class for is_override
620 InstanceKlass* superk = super_method->method_holder();
621 // we want only instance method matches
622 // pretend private methods are not in the super vtable
623 // since we do override around them: e.g. a.m pub/b.m private/c.m pub,
624 // ignore private, c.m pub does override a.m pub
625 // For classes that were not javac'd together, we also do transitive overriding around
626 // methods that have less accessibility
627 if ((!super_method->is_static()) &&
628 (!super_method->is_private())) {
629 if (superk->is_override(super_method, classloader, classname, THREAD)) {
630 return false;
631 // else keep looking for transitive overrides
632 }
633 }
634
635 // Start with lookup result and continue to search up
636 k = superk->super(); // haven't found an override match yet; continue to look
637 }
638
639 // if the target method is public or protected it may have a matching
640 // miranda method in the super, whose entry it should re-use.
641 // Actually, to handle cases that javac would not generate, we need
642 // this check for all access permissions.
643 InstanceKlass *sk = InstanceKlass::cast(super);
644 if (sk->has_miranda_methods()) {
645 if (sk->lookup_method_in_all_interfaces(name, signature, Klass::find_defaults) != NULL) {
646 return false; // found a matching miranda; we do not need a new entry
647 }
648 }
649 return true; // found no match; we need a new entry
650 }
651
652 // Support for miranda methods
653
654 // get the vtable index of a miranda method with matching "name" and "signature"
655 int klassVtable::index_of_miranda(Symbol* name, Symbol* signature) {
656 // search from the bottom, might be faster
657 for (int i = (length() - 1); i >= 0; i--) {
658 Method* m = table()[i].method();
659 if (is_miranda_entry_at(i) &&
660 m->name() == name && m->signature() == signature) {
661 return i;
662 }
663 }
664 return Method::invalid_vtable_index;
665 }
666
667 // check if an entry at an index is miranda
668 // requires that method m at entry be declared ("held") by an interface.
669 bool klassVtable::is_miranda_entry_at(int i) {
670 Method* m = method_at(i);
671 Klass* method_holder = m->method_holder();
672 InstanceKlass *mhk = InstanceKlass::cast(method_holder);
673
674 // miranda methods are public abstract instance interface methods in a class's vtable
675 if (mhk->is_interface()) {
676 assert(m->is_public(), "should be public");
677 assert(ik()->implements_interface(method_holder) , "this class should implement the interface");
678 if (is_miranda(m, ik()->methods(), ik()->default_methods(), ik()->super())) {
679 return true;
680 }
681 }
682 return false;
683 }
684
685 // Check if a method is a miranda method, given a class's methods array,
686 // its default_method table and its super class.
687 // "Miranda" means an abstract non-private method that would not be
688 // overridden for the local class.
689 // A "miranda" method should only include non-private interface
690 // instance methods, i.e. not private methods, not static methods,
691 // not default methods (concrete interface methods), not overpass methods.
692 // If a given class already has a local (including overpass) method, a
693 // default method, or any of its superclasses has the same which would have
694 // overridden an abstract method, then this is not a miranda method.
695 //
696 // Miranda methods are checked multiple times.
697 // Pass 1: during class load/class file parsing: before vtable size calculation:
698 // include superinterface abstract and default methods (non-private instance).
699 // We include potential default methods to give them space in the vtable.
700 // During the first run, the current instanceKlass has not yet been
701 // created, the superclasses and superinterfaces do have instanceKlasses
702 // but may not have vtables, the default_methods list is empty, no overpasses.
703 // This is seen by default method creation.
704 //
705 // Pass 2: recalculated during vtable initialization: only include abstract methods.
706 // The goal of pass 2 is to walk through the superinterfaces to see if any of
707 // the superinterface methods (which were all abstract pre-default methods)
708 // need to be added to the vtable.
709 // With the addition of default methods, we have three new challenges:
710 // overpasses, static interface methods and private interface methods.
711 // Static and private interface methods do not get added to the vtable and
712 // are not seen by the method resolution process, so we skip those.
713 // Overpass methods are already in the vtable, so vtable lookup will
714 // find them and we don't need to add a miranda method to the end of
715 // the vtable. So we look for overpass methods and if they are found we
716 // return false. Note that we inherit our superclasses vtable, so
717 // the superclass' search also needs to use find_overpass so that if
718 // one is found we return false.
719 // False means - we don't need a miranda method added to the vtable.
720 //
721 // During the second run, default_methods is set up, so concrete methods from
722 // superinterfaces with matching names/signatures to default_methods are already
723 // in the default_methods list and do not need to be appended to the vtable
724 // as mirandas. Abstract methods may already have been handled via
725 // overpasses - either local or superclass overpasses, which may be
726 // in the vtable already.
727 //
728 // Pass 3: They are also checked by link resolution and selection,
729 // for invocation on a method (not interface method) reference that
730 // resolves to a method with an interface as its method_holder.
731 // Used as part of walking from the bottom of the vtable to find
732 // the vtable index for the miranda method.
733 //
734 // Part of the Miranda Rights in the US mean that if you do not have
735 // an attorney one will be appointed for you.
736 bool klassVtable::is_miranda(Method* m, Array<Method*>* class_methods,
737 Array<Method*>* default_methods, Klass* super) {
738 if (m->is_static() || m->is_private() || m->is_overpass()) {
739 return false;
740 }
741 Symbol* name = m->name();
742 Symbol* signature = m->signature();
743
744 // First look in local methods to see if already covered
745 if (InstanceKlass::find_local_method(class_methods, name, signature,
746 Klass::find_overpass, Klass::skip_static, Klass::skip_private) != NULL)
747 {
748 return false;
749 }
750
751 // Check local default methods
752 if ((default_methods != NULL) &&
753 (InstanceKlass::find_method(default_methods, name, signature) != NULL))
754 {
755 return false;
756 }
757
758 // Iterate on all superclasses, which should be InstanceKlasses.
759 // Note that we explicitly look for overpasses at each level.
760 // Overpasses may or may not exist for supers for pass 1,
761 // they should have been created for pass 2 and later.
762
763 for (Klass* cursuper = super; cursuper != NULL; cursuper = cursuper->super())
764 {
765 if (InstanceKlass::cast(cursuper)->find_local_method(name, signature,
766 Klass::find_overpass, Klass::skip_static, Klass::skip_private) != NULL) {
767 return false;
768 }
769 }
770
771 return true;
772 }
773
774 // Scans current_interface_methods for miranda methods that do not
775 // already appear in new_mirandas, or default methods, and are also not defined-and-non-private
776 // in super (superclass). These mirandas are added to all_mirandas if it is
777 // not null; in addition, those that are not duplicates of miranda methods
778 // inherited by super from its interfaces are added to new_mirandas.
779 // Thus, new_mirandas will be the set of mirandas that this class introduces,
780 // all_mirandas will be the set of all mirandas applicable to this class
781 // including all defined in superclasses.
782 void klassVtable::add_new_mirandas_to_lists(
783 GrowableArray<Method*>* new_mirandas, GrowableArray<Method*>* all_mirandas,
784 Array<Method*>* current_interface_methods, Array<Method*>* class_methods,
785 Array<Method*>* default_methods, Klass* super) {
786
787 // iterate thru the current interface's method to see if it a miranda
788 int num_methods = current_interface_methods->length();
789 for (int i = 0; i < num_methods; i++) {
790 Method* im = current_interface_methods->at(i);
791 bool is_duplicate = false;
792 int num_of_current_mirandas = new_mirandas->length();
793 // check for duplicate mirandas in different interfaces we implement
794 for (int j = 0; j < num_of_current_mirandas; j++) {
795 Method* miranda = new_mirandas->at(j);
796 if ((im->name() == miranda->name()) &&
797 (im->signature() == miranda->signature())) {
798 is_duplicate = true;
799 break;
800 }
801 }
802
803 if (!is_duplicate) { // we don't want duplicate miranda entries in the vtable
804 if (is_miranda(im, class_methods, default_methods, super)) { // is it a miranda at all?
805 InstanceKlass *sk = InstanceKlass::cast(super);
806 // check if it is a duplicate of a super's miranda
807 if (sk->lookup_method_in_all_interfaces(im->name(), im->signature(), Klass::find_defaults) == NULL) {
808 new_mirandas->append(im);
809 }
810 if (all_mirandas != NULL) {
811 all_mirandas->append(im);
812 }
813 }
814 }
815 }
816 }
817
818 void klassVtable::get_mirandas(GrowableArray<Method*>* new_mirandas,
819 GrowableArray<Method*>* all_mirandas,
820 Klass* super, Array<Method*>* class_methods,
821 Array<Method*>* default_methods,
822 Array<Klass*>* local_interfaces) {
823 assert((new_mirandas->length() == 0) , "current mirandas must be 0");
824
825 // iterate thru the local interfaces looking for a miranda
826 int num_local_ifs = local_interfaces->length();
827 for (int i = 0; i < num_local_ifs; i++) {
828 InstanceKlass *ik = InstanceKlass::cast(local_interfaces->at(i));
829 add_new_mirandas_to_lists(new_mirandas, all_mirandas,
830 ik->methods(), class_methods,
831 default_methods, super);
832 // iterate thru each local's super interfaces
833 Array<Klass*>* super_ifs = ik->transitive_interfaces();
834 int num_super_ifs = super_ifs->length();
835 for (int j = 0; j < num_super_ifs; j++) {
836 InstanceKlass *sik = InstanceKlass::cast(super_ifs->at(j));
837 add_new_mirandas_to_lists(new_mirandas, all_mirandas,
838 sik->methods(), class_methods,
839 default_methods, super);
840 }
841 }
842 }
843
844 // Discover miranda methods ("miranda" = "interface abstract, no binding"),
845 // and append them into the vtable starting at index initialized,
846 // return the new value of initialized.
847 // Miranda methods use vtable entries, but do not get assigned a vtable_index
848 // The vtable_index is discovered by searching from the end of the vtable
849 int klassVtable::fill_in_mirandas(int initialized) {
850 GrowableArray<Method*> mirandas(20);
851 get_mirandas(&mirandas, NULL, ik()->super(), ik()->methods(),
852 ik()->default_methods(), ik()->local_interfaces());
853 for (int i = 0; i < mirandas.length(); i++) {
854 if (PrintVtables && Verbose) {
855 Method* meth = mirandas.at(i);
856 ResourceMark rm(Thread::current());
857 if (meth != NULL) {
858 char* sig = meth->name_and_sig_as_C_string();
859 tty->print("fill in mirandas with %s index %d, flags: ",
860 sig, initialized);
861 meth->access_flags().print_on(tty);
862 if (meth->is_default_method()) {
863 tty->print("default ");
864 }
865 tty->cr();
866 }
867 }
868 put_method_at(mirandas.at(i), initialized);
869 ++initialized;
870 }
871 return initialized;
872 }
873
874 // Copy this class's vtable to the vtable beginning at start.
875 // Used to copy superclass vtable to prefix of subclass's vtable.
876 void klassVtable::copy_vtable_to(vtableEntry* start) {
877 Copy::disjoint_words((HeapWord*)table(), (HeapWord*)start, _length * vtableEntry::size());
878 }
879
880 #if INCLUDE_JVMTI
881 bool klassVtable::adjust_default_method(int vtable_index, Method* old_method, Method* new_method) {
882 // If old_method is default, find this vtable index in default_vtable_indices
883 // and replace that method in the _default_methods list
884 bool updated = false;
885
886 Array<Method*>* default_methods = ik()->default_methods();
887 if (default_methods != NULL) {
888 int len = default_methods->length();
889 for (int idx = 0; idx < len; idx++) {
890 if (vtable_index == ik()->default_vtable_indices()->at(idx)) {
891 if (default_methods->at(idx) == old_method) {
892 default_methods->at_put(idx, new_method);
893 updated = true;
894 }
895 break;
896 }
897 }
898 }
899 return updated;
900 }
901
902 // search the vtable for uses of either obsolete or EMCP methods
903 void klassVtable::adjust_method_entries(InstanceKlass* holder, bool * trace_name_printed) {
904 int prn_enabled = 0;
905 for (int index = 0; index < length(); index++) {
906 Method* old_method = unchecked_method_at(index);
907 if (old_method == NULL || old_method->method_holder() != holder || !old_method->is_old()) {
908 continue; // skip uninteresting entries
909 }
910 assert(!old_method->is_deleted(), "vtable methods may not be deleted");
911
912 Method* new_method = holder->method_with_idnum(old_method->orig_method_idnum());
913
914 assert(new_method != NULL, "method_with_idnum() should not be NULL");
915 assert(old_method != new_method, "sanity check");
916
917 put_method_at(new_method, index);
918 // For default methods, need to update the _default_methods array
919 // which can only have one method entry for a given signature
920 bool updated_default = false;
921 if (old_method->is_default_method()) {
922 updated_default = adjust_default_method(index, old_method, new_method);
923 }
924
925 if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
926 if (!(*trace_name_printed)) {
927 // RC_TRACE_MESG macro has an embedded ResourceMark
928 RC_TRACE_MESG(("adjust: klassname=%s for methods from name=%s",
929 klass()->external_name(),
930 old_method->method_holder()->external_name()));
931 *trace_name_printed = true;
932 }
933 // RC_TRACE macro has an embedded ResourceMark
934 RC_TRACE(0x00100000, ("vtable method update: %s(%s), updated default = %s",
935 new_method->name()->as_C_string(),
936 new_method->signature()->as_C_string(),
937 updated_default ? "true" : "false"));
938 }
939 }
940 }
941
942 // a vtable should never contain old or obsolete methods
943 bool klassVtable::check_no_old_or_obsolete_entries() {
944 for (int i = 0; i < length(); i++) {
945 Method* m = unchecked_method_at(i);
946 if (m != NULL &&
947 (NOT_PRODUCT(!m->is_valid() ||) m->is_old() || m->is_obsolete())) {
948 return false;
949 }
950 }
951 return true;
952 }
953
954 void klassVtable::dump_vtable() {
955 tty->print_cr("vtable dump --");
956 for (int i = 0; i < length(); i++) {
957 Method* m = unchecked_method_at(i);
958 if (m != NULL) {
959 tty->print(" (%5d) ", i);
960 m->access_flags().print_on(tty);
961 if (m->is_default_method()) {
962 tty->print("default ");
963 }
964 if (m->is_overpass()) {
965 tty->print("overpass");
966 }
967 tty->print(" -- ");
968 m->print_name(tty);
969 tty->cr();
970 }
971 }
972 }
973 #endif // INCLUDE_JVMTI
974
975 // CDS/RedefineClasses support - clear vtables so they can be reinitialized
976 void klassVtable::clear_vtable() {
977 for (int i = 0; i < _length; i++) table()[i].clear();
978 }
979
980 bool klassVtable::is_initialized() {
981 return _length == 0 || table()[0].method() != NULL;
982 }
983
984 //-----------------------------------------------------------------------------------------
985 // Itable code
986
987 // Initialize a itableMethodEntry
988 void itableMethodEntry::initialize(Method* m) {
989 if (m == NULL) return;
990
991 _method = m;
992 }
993
994 klassItable::klassItable(instanceKlassHandle klass) {
995 _klass = klass;
996
997 if (klass->itable_length() > 0) {
998 itableOffsetEntry* offset_entry = (itableOffsetEntry*)klass->start_of_itable();
999 if (offset_entry != NULL && offset_entry->interface_klass() != NULL) { // Check that itable is initialized
1000 // First offset entry points to the first method_entry
1001 intptr_t* method_entry = (intptr_t *)(((address)klass()) + offset_entry->offset());
1002 intptr_t* end = klass->end_of_itable();
1003
1004 _table_offset = (intptr_t*)offset_entry - (intptr_t*)klass();
1005 _size_offset_table = (method_entry - ((intptr_t*)offset_entry)) / itableOffsetEntry::size();
1006 _size_method_table = (end - method_entry) / itableMethodEntry::size();
1007 assert(_table_offset >= 0 && _size_offset_table >= 0 && _size_method_table >= 0, "wrong computation");
1008 return;
1009 }
1010 }
1011
1012 // The length of the itable was either zero, or it has not yet been initialized.
1013 _table_offset = 0;
1014 _size_offset_table = 0;
1015 _size_method_table = 0;
1016 }
1017
1018 static int initialize_count = 0;
1019
1020 // Initialization
1021 void klassItable::initialize_itable(bool checkconstraints, TRAPS) {
1022 if (_klass->is_interface()) {
1023 // This needs to go after vtable indices are assigned but
1024 // before implementors need to know the number of itable indices.
1025 assign_itable_indices_for_interface(_klass());
1026 }
1027
1028 // Cannot be setup doing bootstrapping, interfaces don't have
1029 // itables, and klass with only ones entry have empty itables
1030 if (Universe::is_bootstrapping() ||
1031 _klass->is_interface() ||
1032 _klass->itable_length() == itableOffsetEntry::size()) return;
1033
1034 // There's alway an extra itable entry so we can null-terminate it.
1035 guarantee(size_offset_table() >= 1, "too small");
1036 int num_interfaces = size_offset_table() - 1;
1037 if (num_interfaces > 0) {
1038 if (TraceItables) tty->print_cr("%3d: Initializing itables for %s", ++initialize_count,
1039 _klass->name()->as_C_string());
1040
1041
1042 // Iterate through all interfaces
1043 int i;
1044 for(i = 0; i < num_interfaces; i++) {
1045 itableOffsetEntry* ioe = offset_entry(i);
1046 HandleMark hm(THREAD);
1047 KlassHandle interf_h (THREAD, ioe->interface_klass());
1048 assert(interf_h() != NULL && ioe->offset() != 0, "bad offset entry in itable");
1049 initialize_itable_for_interface(ioe->offset(), interf_h, checkconstraints, CHECK);
1050 }
1051
1052 }
1053 // Check that the last entry is empty
1054 itableOffsetEntry* ioe = offset_entry(size_offset_table() - 1);
1055 guarantee(ioe->interface_klass() == NULL && ioe->offset() == 0, "terminator entry missing");
1056 }
1057
1058
1059 inline bool interface_method_needs_itable_index(Method* m) {
1060 if (m->is_static()) return false; // e.g., Stream.empty
1061 if (m->is_initializer()) return false; // <init> or <clinit>
1062 // If an interface redeclares a method from java.lang.Object,
1063 // it should already have a vtable index, don't touch it.
1064 // e.g., CharSequence.toString (from initialize_vtable)
1065 // if (m->has_vtable_index()) return false; // NO!
1066 return true;
1067 }
1068
1069 int klassItable::assign_itable_indices_for_interface(Klass* klass) {
1070 // an interface does not have an itable, but its methods need to be numbered
1071 if (TraceItables) tty->print_cr("%3d: Initializing itable indices for interface %s", ++initialize_count,
1072 klass->name()->as_C_string());
1073 Array<Method*>* methods = InstanceKlass::cast(klass)->methods();
1074 int nof_methods = methods->length();
1075 int ime_num = 0;
1076 for (int i = 0; i < nof_methods; i++) {
1077 Method* m = methods->at(i);
1078 if (interface_method_needs_itable_index(m)) {
1079 assert(!m->is_final_method(), "no final interface methods");
1080 // If m is already assigned a vtable index, do not disturb it.
1081 if (TraceItables && Verbose) {
1082 ResourceMark rm;
1083 const char* sig = (m != NULL) ? m->name_and_sig_as_C_string() : "<NULL>";
1084 if (m->has_vtable_index()) {
1085 tty->print("vtable index %d for method: %s, flags: ", m->vtable_index(), sig);
1086 } else {
1087 tty->print("itable index %d for method: %s, flags: ", ime_num, sig);
1088 }
1089 if (m != NULL) {
1090 m->access_flags().print_on(tty);
1091 if (m->is_default_method()) {
1092 tty->print("default ");
1093 }
1094 if (m->is_overpass()) {
1095 tty->print("overpass");
1096 }
1097 }
1098 tty->cr();
1099 }
1100 if (!m->has_vtable_index()) {
1101 assert(m->vtable_index() == Method::pending_itable_index, "set by initialize_vtable");
1102 m->set_itable_index(ime_num);
1103 // Progress to next itable entry
1104 ime_num++;
1105 }
1106 }
1107 }
1108 assert(ime_num == method_count_for_interface(klass), "proper sizing");
1109 return ime_num;
1110 }
1111
1112 int klassItable::method_count_for_interface(Klass* interf) {
1113 assert(interf->is_instance_klass(), "must be");
1114 assert(interf->is_interface(), "must be");
1115 Array<Method*>* methods = InstanceKlass::cast(interf)->methods();
1116 int nof_methods = methods->length();
1117 int length = 0;
1118 while (nof_methods > 0) {
1119 Method* m = methods->at(nof_methods-1);
1120 if (m->has_itable_index()) {
1121 length = m->itable_index() + 1;
1122 break;
1123 }
1124 nof_methods -= 1;
1125 }
1126 #ifdef ASSERT
1127 int nof_methods_copy = nof_methods;
1128 while (nof_methods_copy > 0) {
1129 Method* mm = methods->at(--nof_methods_copy);
1130 assert(!mm->has_itable_index() || mm->itable_index() < length, "");
1131 }
1132 #endif //ASSERT
1133 // return the rightmost itable index, plus one; or 0 if no methods have
1134 // itable indices
1135 return length;
1136 }
1137
1138
1139 void klassItable::initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS) {
1140 Array<Method*>* methods = InstanceKlass::cast(interf_h())->methods();
1141 int nof_methods = methods->length();
1142 HandleMark hm;
1143 assert(nof_methods > 0, "at least one method must exist for interface to be in vtable");
1144 Handle interface_loader (THREAD, InstanceKlass::cast(interf_h())->class_loader());
1145
1146 int ime_count = method_count_for_interface(interf_h());
1147 for (int i = 0; i < nof_methods; i++) {
1148 Method* m = methods->at(i);
1149 methodHandle target;
1150 if (m->has_itable_index()) {
1151 // This search must match the runtime resolution, i.e. selection search for invokeinterface
1152 // to correctly enforce loader constraints for interface method inheritance
1153 target = LinkResolver::lookup_instance_method_in_klasses(_klass, m->name(), m->signature(), CHECK);
1154 }
1155 if (target == NULL || !target->is_public() || target->is_abstract()) {
1156 // Entry does not resolve. Leave it empty for AbstractMethodError.
1157 if (!(target == NULL) && !target->is_public()) {
1158 // Stuff an IllegalAccessError throwing method in there instead.
1159 itableOffsetEntry::method_entry(_klass(), method_table_offset)[m->itable_index()].
1160 initialize(Universe::throw_illegal_access_error());
1161 }
1162 } else {
1163 // Entry did resolve, check loader constraints before initializing
1164 // if checkconstraints requested
1165 if (checkconstraints) {
1166 Handle method_holder_loader (THREAD, target->method_holder()->class_loader());
1167 if (method_holder_loader() != interface_loader()) {
1168 ResourceMark rm(THREAD);
1169 Symbol* failed_type_symbol =
1170 SystemDictionary::check_signature_loaders(m->signature(),
1171 method_holder_loader,
1172 interface_loader,
1173 true, CHECK);
1174 if (failed_type_symbol != NULL) {
1175 const char* msg = "loader constraint violation in interface "
1176 "itable initialization: when resolving method \"%s\" the class"
1177 " loader (instance of %s) of the current class, %s, "
1178 "and the class loader (instance of %s) for interface "
1179 "%s have different Class objects for the type %s "
1180 "used in the signature";
1181 char* sig = target()->name_and_sig_as_C_string();
1182 const char* loader1 = SystemDictionary::loader_name(method_holder_loader());
1183 char* current = _klass->name()->as_C_string();
1184 const char* loader2 = SystemDictionary::loader_name(interface_loader());
1185 char* iface = InstanceKlass::cast(interf_h())->name()->as_C_string();
1186 char* failed_type_name = failed_type_symbol->as_C_string();
1187 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
1188 strlen(current) + strlen(loader2) + strlen(iface) +
1189 strlen(failed_type_name);
1190 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
1191 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2,
1192 iface, failed_type_name);
1193 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
1194 }
1195 }
1196 }
1197
1198 // ime may have moved during GC so recalculate address
1199 int ime_num = m->itable_index();
1200 assert(ime_num < ime_count, "oob");
1201 itableOffsetEntry::method_entry(_klass(), method_table_offset)[ime_num].initialize(target());
1202 if (TraceItables && Verbose) {
1203 ResourceMark rm(THREAD);
1204 if (target() != NULL) {
1205 char* sig = target()->name_and_sig_as_C_string();
1206 tty->print("interface: %s, ime_num: %d, target: %s, method_holder: %s ",
1207 interf_h()->internal_name(), ime_num, sig,
1208 target()->method_holder()->internal_name());
1209 tty->print("target_method flags: ");
1210 target()->access_flags().print_on(tty);
1211 if (target()->is_default_method()) {
1212 tty->print("default ");
1213 }
1214 tty->cr();
1215 }
1216 }
1217 }
1218 }
1219 }
1220
1221 // Update entry for specific Method*
1222 void klassItable::initialize_with_method(Method* m) {
1223 itableMethodEntry* ime = method_entry(0);
1224 for(int i = 0; i < _size_method_table; i++) {
1225 if (ime->method() == m) {
1226 ime->initialize(m);
1227 }
1228 ime++;
1229 }
1230 }
1231
1232 #if INCLUDE_JVMTI
1233 // search the itable for uses of either obsolete or EMCP methods
1234 void klassItable::adjust_method_entries(InstanceKlass* holder, bool * trace_name_printed) {
1235
1236 itableMethodEntry* ime = method_entry(0);
1237 for (int i = 0; i < _size_method_table; i++, ime++) {
1238 Method* old_method = ime->method();
1239 if (old_method == NULL || old_method->method_holder() != holder || !old_method->is_old()) {
1240 continue; // skip uninteresting entries
1241 }
1242 assert(!old_method->is_deleted(), "itable methods may not be deleted");
1243
1244 Method* new_method = holder->method_with_idnum(old_method->orig_method_idnum());
1245
1246 assert(new_method != NULL, "method_with_idnum() should not be NULL");
1247 assert(old_method != new_method, "sanity check");
1248
1249 ime->initialize(new_method);
1250
1251 if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
1252 if (!(*trace_name_printed)) {
1253 // RC_TRACE_MESG macro has an embedded ResourceMark
1254 RC_TRACE_MESG(("adjust: name=%s",
1255 old_method->method_holder()->external_name()));
1256 *trace_name_printed = true;
1257 }
1258 // RC_TRACE macro has an embedded ResourceMark
1259 RC_TRACE(0x00200000, ("itable method update: %s(%s)",
1260 new_method->name()->as_C_string(),
1261 new_method->signature()->as_C_string()));
1262 }
1263 }
1264 }
1265
1266 // an itable should never contain old or obsolete methods
1267 bool klassItable::check_no_old_or_obsolete_entries() {
1268 itableMethodEntry* ime = method_entry(0);
1269 for (int i = 0; i < _size_method_table; i++) {
1270 Method* m = ime->method();
1271 if (m != NULL &&
1272 (NOT_PRODUCT(!m->is_valid() ||) m->is_old() || m->is_obsolete())) {
1273 return false;
1274 }
1275 ime++;
1276 }
1277 return true;
1278 }
1279
1280 void klassItable::dump_itable() {
1281 itableMethodEntry* ime = method_entry(0);
1282 tty->print_cr("itable dump --");
1283 for (int i = 0; i < _size_method_table; i++) {
1284 Method* m = ime->method();
1285 if (m != NULL) {
1286 tty->print(" (%5d) ", i);
1287 m->access_flags().print_on(tty);
1288 if (m->is_default_method()) {
1289 tty->print("default ");
1290 }
1291 tty->print(" -- ");
1292 m->print_name(tty);
1293 tty->cr();
1294 }
1295 ime++;
1296 }
1297 }
1298 #endif // INCLUDE_JVMTI
1299
1300
1301 // Setup
1302 class InterfaceVisiterClosure : public StackObj {
1303 public:
1304 virtual void doit(Klass* intf, int method_count) = 0;
1305 };
1306
1307 // Visit all interfaces with at least one itable method
1308 void visit_all_interfaces(Array<Klass*>* transitive_intf, InterfaceVisiterClosure *blk) {
1309 // Handle array argument
1310 for(int i = 0; i < transitive_intf->length(); i++) {
1311 Klass* intf = transitive_intf->at(i);
1312 assert(intf->is_interface(), "sanity check");
1313
1314 // Find no. of itable methods
1315 int method_count = 0;
1316 // method_count = klassItable::method_count_for_interface(intf);
1317 Array<Method*>* methods = InstanceKlass::cast(intf)->methods();
1318 if (methods->length() > 0) {
1319 for (int i = methods->length(); --i >= 0; ) {
1320 if (interface_method_needs_itable_index(methods->at(i))) {
1321 method_count++;
1322 }
1323 }
1324 }
1325
1326 // Only count interfaces with at least one method
1327 if (method_count > 0) {
1328 blk->doit(intf, method_count);
1329 }
1330 }
1331 }
1332
1333 class CountInterfacesClosure : public InterfaceVisiterClosure {
1334 private:
1335 int _nof_methods;
1336 int _nof_interfaces;
1337 public:
1338 CountInterfacesClosure() { _nof_methods = 0; _nof_interfaces = 0; }
1339
1340 int nof_methods() const { return _nof_methods; }
1341 int nof_interfaces() const { return _nof_interfaces; }
1342
1343 void doit(Klass* intf, int method_count) { _nof_methods += method_count; _nof_interfaces++; }
1344 };
1345
1346 class SetupItableClosure : public InterfaceVisiterClosure {
1347 private:
1348 itableOffsetEntry* _offset_entry;
1349 itableMethodEntry* _method_entry;
1350 address _klass_begin;
1351 public:
1352 SetupItableClosure(address klass_begin, itableOffsetEntry* offset_entry, itableMethodEntry* method_entry) {
1353 _klass_begin = klass_begin;
1354 _offset_entry = offset_entry;
1355 _method_entry = method_entry;
1356 }
1357
1358 itableMethodEntry* method_entry() const { return _method_entry; }
1359
1360 void doit(Klass* intf, int method_count) {
1361 int offset = ((address)_method_entry) - _klass_begin;
1362 _offset_entry->initialize(intf, offset);
1363 _offset_entry++;
1364 _method_entry += method_count;
1365 }
1366 };
1367
1368 int klassItable::compute_itable_size(Array<Klass*>* transitive_interfaces) {
1369 // Count no of interfaces and total number of interface methods
1370 CountInterfacesClosure cic;
1371 visit_all_interfaces(transitive_interfaces, &cic);
1372
1373 // There's alway an extra itable entry so we can null-terminate it.
1374 int itable_size = calc_itable_size(cic.nof_interfaces() + 1, cic.nof_methods());
1375
1376 // Statistics
1377 update_stats(itable_size * HeapWordSize);
1378
1379 return itable_size;
1380 }
1381
1382
1383 // Fill out offset table and interface klasses into the itable space
1384 void klassItable::setup_itable_offset_table(instanceKlassHandle klass) {
1385 if (klass->itable_length() == 0) return;
1386 assert(!klass->is_interface(), "Should have zero length itable");
1387
1388 // Count no of interfaces and total number of interface methods
1389 CountInterfacesClosure cic;
1390 visit_all_interfaces(klass->transitive_interfaces(), &cic);
1391 int nof_methods = cic.nof_methods();
1392 int nof_interfaces = cic.nof_interfaces();
1393
1394 // Add one extra entry so we can null-terminate the table
1395 nof_interfaces++;
1396
1397 assert(compute_itable_size(klass->transitive_interfaces()) ==
1398 calc_itable_size(nof_interfaces, nof_methods),
1399 "mismatch calculation of itable size");
1400
1401 // Fill-out offset table
1402 itableOffsetEntry* ioe = (itableOffsetEntry*)klass->start_of_itable();
1403 itableMethodEntry* ime = (itableMethodEntry*)(ioe + nof_interfaces);
1404 intptr_t* end = klass->end_of_itable();
1405 assert((oop*)(ime + nof_methods) <= (oop*)klass->start_of_nonstatic_oop_maps(), "wrong offset calculation (1)");
1406 assert((oop*)(end) == (oop*)(ime + nof_methods), "wrong offset calculation (2)");
1407
1408 // Visit all interfaces and initialize itable offset table
1409 SetupItableClosure sic((address)klass(), ioe, ime);
1410 visit_all_interfaces(klass->transitive_interfaces(), &sic);
1411
1412 #ifdef ASSERT
1413 ime = sic.method_entry();
1414 oop* v = (oop*) klass->end_of_itable();
1415 assert( (oop*)(ime) == v, "wrong offset calculation (2)");
1416 #endif
1417 }
1418
1419
1420 // inverse to itable_index
1421 Method* klassItable::method_for_itable_index(Klass* intf, int itable_index) {
1422 assert(InstanceKlass::cast(intf)->is_interface(), "sanity check");
1423 assert(intf->verify_itable_index(itable_index), "");
1424 Array<Method*>* methods = InstanceKlass::cast(intf)->methods();
1425
1426 if (itable_index < 0 || itable_index >= method_count_for_interface(intf))
1427 return NULL; // help caller defend against bad indices
1428
1429 int index = itable_index;
1430 Method* m = methods->at(index);
1431 int index2 = -1;
1432 while (!m->has_itable_index() ||
1433 (index2 = m->itable_index()) != itable_index) {
1434 assert(index2 < itable_index, "monotonic");
1435 if (++index == methods->length())
1436 return NULL;
1437 m = methods->at(index);
1438 }
1439 assert(m->itable_index() == itable_index, "correct inverse");
1440
1441 return m;
1442 }
1443
1444 void klassVtable::verify(outputStream* st, bool forced) {
1445 // make sure table is initialized
1446 if (!Universe::is_fully_initialized()) return;
1447 #ifndef PRODUCT
1448 // avoid redundant verifies
1449 if (!forced && _verify_count == Universe::verify_count()) return;
1450 _verify_count = Universe::verify_count();
1451 #endif
1452 oop* end_of_obj = (oop*)_klass() + _klass()->size();
1453 oop* end_of_vtable = (oop *)&table()[_length];
1454 if (end_of_vtable > end_of_obj) {
1455 fatal("klass %s: klass object too short (vtable extends beyond end)",
1456 _klass->internal_name());
1457 }
1458
1459 for (int i = 0; i < _length; i++) table()[i].verify(this, st);
1460 // verify consistency with superKlass vtable
1461 Klass* super = _klass->super();
1462 if (super != NULL) {
1463 InstanceKlass* sk = InstanceKlass::cast(super);
1464 klassVtable* vt = sk->vtable();
1465 for (int i = 0; i < vt->length(); i++) {
1466 verify_against(st, vt, i);
1467 }
1468 }
1469 }
1470
1471 void klassVtable::verify_against(outputStream* st, klassVtable* vt, int index) {
1472 vtableEntry* vte = &vt->table()[index];
1473 if (vte->method()->name() != table()[index].method()->name() ||
1474 vte->method()->signature() != table()[index].method()->signature()) {
1475 fatal("mismatched name/signature of vtable entries");
1476 }
1477 }
1478
1479 #ifndef PRODUCT
1480 void klassVtable::print() {
1481 ResourceMark rm;
1482 tty->print("klassVtable for klass %s (length %d):\n", _klass->internal_name(), length());
1483 for (int i = 0; i < length(); i++) {
1484 table()[i].print();
1485 tty->cr();
1486 }
1487 }
1488 #endif
1489
1490 void vtableEntry::verify(klassVtable* vt, outputStream* st) {
1491 NOT_PRODUCT(FlagSetting fs(IgnoreLockingAssertions, true));
1492 assert(method() != NULL, "must have set method");
1493 method()->verify();
1494 // we sub_type, because it could be a miranda method
1495 if (!vt->klass()->is_subtype_of(method()->method_holder())) {
1496 #ifndef PRODUCT
1497 print();
1498 #endif
1499 fatal("vtableEntry " PTR_FORMAT ": method is from subclass", p2i(this));
1500 }
1501 }
1502
1503 #ifndef PRODUCT
1504
1505 void vtableEntry::print() {
1506 ResourceMark rm;
1507 tty->print("vtableEntry %s: ", method()->name()->as_C_string());
1508 if (Verbose) {
1509 tty->print("m " PTR_FORMAT " ", p2i(method()));
1510 }
1511 }
1512
1513 class VtableStats : AllStatic {
1514 public:
1515 static int no_klasses; // # classes with vtables
1516 static int no_array_klasses; // # array classes
1517 static int no_instance_klasses; // # instanceKlasses
1518 static int sum_of_vtable_len; // total # of vtable entries
1519 static int sum_of_array_vtable_len; // total # of vtable entries in array klasses only
1520 static int fixed; // total fixed overhead in bytes
1521 static int filler; // overhead caused by filler bytes
1522 static int entries; // total bytes consumed by vtable entries
1523 static int array_entries; // total bytes consumed by array vtable entries
1524
1525 static void do_class(Klass* k) {
1526 Klass* kl = k;
1527 klassVtable* vt = kl->vtable();
1528 if (vt == NULL) return;
1529 no_klasses++;
1530 if (kl->is_instance_klass()) {
1531 no_instance_klasses++;
1532 kl->array_klasses_do(do_class);
1533 }
1534 if (kl->is_array_klass()) {
1535 no_array_klasses++;
1536 sum_of_array_vtable_len += vt->length();
1537 }
1538 sum_of_vtable_len += vt->length();
1539 }
1540
1541 static void compute() {
1542 SystemDictionary::classes_do(do_class);
1543 fixed = no_klasses * oopSize; // vtable length
1544 // filler size is a conservative approximation
1545 filler = oopSize * (no_klasses - no_instance_klasses) * (sizeof(InstanceKlass) - sizeof(ArrayKlass) - 1);
1546 entries = sizeof(vtableEntry) * sum_of_vtable_len;
1547 array_entries = sizeof(vtableEntry) * sum_of_array_vtable_len;
1548 }
1549 };
1550
1551 int VtableStats::no_klasses = 0;
1552 int VtableStats::no_array_klasses = 0;
1553 int VtableStats::no_instance_klasses = 0;
1554 int VtableStats::sum_of_vtable_len = 0;
1555 int VtableStats::sum_of_array_vtable_len = 0;
1556 int VtableStats::fixed = 0;
1557 int VtableStats::filler = 0;
1558 int VtableStats::entries = 0;
1559 int VtableStats::array_entries = 0;
1560
1561 void klassVtable::print_statistics() {
1562 ResourceMark rm;
1563 HandleMark hm;
1564 VtableStats::compute();
1565 tty->print_cr("vtable statistics:");
1566 tty->print_cr("%6d classes (%d instance, %d array)", VtableStats::no_klasses, VtableStats::no_instance_klasses, VtableStats::no_array_klasses);
1567 int total = VtableStats::fixed + VtableStats::filler + VtableStats::entries;
1568 tty->print_cr("%6d bytes fixed overhead (refs + vtable object header)", VtableStats::fixed);
1569 tty->print_cr("%6d bytes filler overhead", VtableStats::filler);
1570 tty->print_cr("%6d bytes for vtable entries (%d for arrays)", VtableStats::entries, VtableStats::array_entries);
1571 tty->print_cr("%6d bytes total", total);
1572 }
1573
1574 int klassItable::_total_classes; // Total no. of classes with itables
1575 long klassItable::_total_size; // Total no. of bytes used for itables
1576
1577 void klassItable::print_statistics() {
1578 tty->print_cr("itable statistics:");
1579 tty->print_cr("%6d classes with itables", _total_classes);
1580 tty->print_cr("%6lu K uses for itables (average by class: %ld bytes)", _total_size / K, _total_size / _total_classes);
1581 }
1582
1583 #endif // PRODUCT