1 /*
2 * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/systemDictionary.hpp"
27 #include "classfile/vmSymbols.hpp"
28 #include "gc_implementation/shared/markSweep.inline.hpp"
29 #include "memory/gcLocker.hpp"
30 #include "memory/resourceArea.hpp"
31 #include "memory/universe.inline.hpp"
32 #include "oops/instanceKlass.hpp"
33 #include "oops/klassOop.hpp"
34 #include "oops/klassVtable.hpp"
35 #include "oops/methodOop.hpp"
36 #include "oops/objArrayOop.hpp"
37 #include "oops/oop.inline.hpp"
38 #include "prims/jvmtiRedefineClassesTrace.hpp"
39 #include "runtime/arguments.hpp"
40 #include "runtime/handles.inline.hpp"
41 #include "utilities/copy.hpp"
42
43 inline instanceKlass* klassVtable::ik() const {
44 Klass* k = _klass()->klass_part();
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. Let's say there is a method m in I that neither C nor any
54 // of its super classes implement (i.e there is no method of any access, with
55 // the same name and signature as m), then m is a Miranda method which is
56 // entered as a public abstract method in C's vtable. From then on it should
57 // treated as any other public method in C for method over-ride purposes.
58 void klassVtable::compute_vtable_size_and_num_mirandas(int &vtable_length,
59 int &num_miranda_methods,
60 klassOop super,
61 objArrayOop methods,
62 AccessFlags class_flags,
63 Handle classloader,
64 Symbol* classname,
65 objArrayOop local_interfaces,
66 TRAPS
67 ) {
68
69 No_Safepoint_Verifier nsv;
70
71 // set up default result values
72 vtable_length = 0;
73 num_miranda_methods = 0;
74
75 // start off with super's vtable length
76 instanceKlass* sk = (instanceKlass*)super->klass_part();
77 vtable_length = super == NULL ? 0 : sk->vtable_length();
78
79 // go thru each method in the methods table to see if it needs a new entry
80 int len = methods->length();
81 for (int i = 0; i < len; i++) {
82 assert(methods->obj_at(i)->is_method(), "must be a methodOop");
83 methodHandle mh(THREAD, methodOop(methods->obj_at(i)));
84
85 if (needs_new_vtable_entry(mh, super, classloader, classname, class_flags, THREAD)) {
86 vtable_length += vtableEntry::size(); // we need a new entry
87 }
88 }
89
90 // compute the number of mirandas methods that must be added to the end
91 num_miranda_methods = get_num_mirandas(super, methods, local_interfaces);
92 vtable_length += (num_miranda_methods * vtableEntry::size());
93
94 if (Universe::is_bootstrapping() && vtable_length == 0) {
95 // array classes don't have their superclass set correctly during
96 // bootstrapping
97 vtable_length = Universe::base_vtable_size();
98 }
99
100 if (super == NULL && !Universe::is_bootstrapping() &&
101 vtable_length != Universe::base_vtable_size()) {
102 // Someone is attempting to redefine java.lang.Object incorrectly. The
103 // only way this should happen is from
104 // SystemDictionary::resolve_from_stream(), which will detect this later
105 // and throw a security exception. So don't assert here to let
106 // the exception occur.
107 vtable_length = Universe::base_vtable_size();
108 }
109 assert(super != NULL || vtable_length == Universe::base_vtable_size(),
110 "bad vtable size for class Object");
111 assert(vtable_length % vtableEntry::size() == 0, "bad vtable length");
112 assert(vtable_length >= Universe::base_vtable_size(), "vtable too small");
113 }
114
115 int klassVtable::index_of(methodOop m, int len) const {
116 assert(m->vtable_index() >= 0, "do not ask this of non-vtable methods");
117 return m->vtable_index();
118 }
119
120 int klassVtable::initialize_from_super(KlassHandle super) {
121 if (super.is_null()) {
122 return 0;
123 } else {
124 // copy methods from superKlass
125 // can't inherit from array class, so must be instanceKlass
126 assert(super->oop_is_instance(), "must be instance klass");
127 instanceKlass* sk = (instanceKlass*)super()->klass_part();
128 klassVtable* superVtable = sk->vtable();
129 assert(superVtable->length() <= _length, "vtable too short");
130 #ifdef ASSERT
131 superVtable->verify(tty, true);
132 #endif
133 superVtable->copy_vtable_to(table());
134 #ifndef PRODUCT
135 if (PrintVtables && Verbose) {
136 ResourceMark rm;
137 tty->print_cr("copy vtable from %s to %s size %d", sk->internal_name(), klass()->internal_name(), _length);
138 }
139 #endif
140 return superVtable->length();
141 }
142 }
143
144 // Revised lookup semantics introduced 1.3 (Kestral beta)
145 void klassVtable::initialize_vtable(bool checkconstraints, TRAPS) {
146
147 // Note: Arrays can have intermediate array supers. Use java_super to skip them.
148 KlassHandle super (THREAD, klass()->java_super());
149 int nofNewEntries = 0;
150
151
152 if (PrintVtables && !klass()->oop_is_array()) {
153 ResourceMark rm(THREAD);
154 tty->print_cr("Initializing: %s", _klass->name()->as_C_string());
155 }
156
157 #ifdef ASSERT
158 oop* end_of_obj = (oop*)_klass() + _klass()->size();
159 oop* end_of_vtable = (oop*)&table()[_length];
160 assert(end_of_vtable <= end_of_obj, "vtable extends beyond end");
161 #endif
162
163 if (Universe::is_bootstrapping()) {
164 // just clear everything
165 for (int i = 0; i < _length; i++) table()[i].clear();
166 return;
167 }
168
169 int super_vtable_len = initialize_from_super(super);
170 if (klass()->oop_is_array()) {
171 assert(super_vtable_len == _length, "arrays shouldn't introduce new methods");
172 } else {
173 assert(_klass->oop_is_instance(), "must be instanceKlass");
174
175 objArrayHandle methods(THREAD, ik()->methods());
176 int len = methods()->length();
177 int initialized = super_vtable_len;
178
179 // update_inherited_vtable can stop for gc - ensure using handles
180 for (int i = 0; i < len; i++) {
181 HandleMark hm(THREAD);
182 assert(methods()->obj_at(i)->is_method(), "must be a methodOop");
183 methodHandle mh(THREAD, (methodOop)methods()->obj_at(i));
184
185 bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, checkconstraints, CHECK);
186
187 if (needs_new_entry) {
188 put_method_at(mh(), initialized);
189 mh()->set_vtable_index(initialized); // set primary vtable index
190 initialized++;
191 }
192 }
193
194 // add miranda methods; it will also update the value of initialized
195 fill_in_mirandas(initialized);
196
197 // In class hierarchies where the accessibility is not increasing (i.e., going from private ->
198 // package_private -> publicprotected), the vtable might actually be smaller than our initial
199 // calculation.
200 assert(initialized <= _length, "vtable initialization failed");
201 for(;initialized < _length; initialized++) {
202 put_method_at(NULL, initialized);
203 }
204 NOT_PRODUCT(verify(tty, true));
205 }
206 }
207
208 // Called for cases where a method does not override its superclass' vtable entry
209 // For bytecodes not produced by javac together it is possible that a method does not override
210 // the superclass's method, but might indirectly override a super-super class's vtable entry
211 // If none found, return a null superk, else return the superk of the method this does override
212 instanceKlass* klassVtable::find_transitive_override(instanceKlass* initialsuper, methodHandle target_method,
213 int vtable_index, Handle target_loader, Symbol* target_classname, Thread * THREAD) {
214 instanceKlass* superk = initialsuper;
215 while (superk != NULL && superk->super() != NULL) {
216 instanceKlass* supersuperklass = instanceKlass::cast(superk->super());
217 klassVtable* ssVtable = supersuperklass->vtable();
218 if (vtable_index < ssVtable->length()) {
219 methodOop super_method = ssVtable->method_at(vtable_index);
220 #ifndef PRODUCT
221 Symbol* name= target_method()->name();
222 Symbol* signature = target_method()->signature();
223 assert(super_method->name() == name && super_method->signature() == signature, "vtable entry name/sig mismatch");
224 #endif
225 if (supersuperklass->is_override(super_method, target_loader, target_classname, THREAD)) {
226 #ifndef PRODUCT
227 if (PrintVtables && Verbose) {
228 ResourceMark rm(THREAD);
229 tty->print("transitive overriding superclass %s with %s::%s index %d, original flags: ",
230 supersuperklass->internal_name(),
231 _klass->internal_name(), (target_method() != NULL) ?
232 target_method()->name()->as_C_string() : "<NULL>", vtable_index);
233 super_method->access_flags().print_on(tty);
234 tty->print("overriders flags: ");
235 target_method->access_flags().print_on(tty);
236 tty->cr();
237 }
238 #endif /*PRODUCT*/
239 break; // return found superk
240 }
241 } else {
242 // super class has no vtable entry here, stop transitive search
243 superk = (instanceKlass*)NULL;
244 break;
245 }
246 // if no override found yet, continue to search up
247 superk = instanceKlass::cast(superk->super());
248 }
249
250 return superk;
251 }
252
253
254 // Update child's copy of super vtable for overrides
255 // OR return true if a new vtable entry is required
256 // Only called for instanceKlass's, i.e. not for arrays
257 // If that changed, could not use _klass as handle for klass
258 bool klassVtable::update_inherited_vtable(instanceKlass* klass, methodHandle target_method, int super_vtable_len,
259 bool checkconstraints, TRAPS) {
260 ResourceMark rm;
261 bool allocate_new = true;
262 assert(klass->oop_is_instance(), "must be instanceKlass");
263
264 // Initialize the method's vtable index to "nonvirtual".
265 // If we allocate a vtable entry, we will update it to a non-negative number.
266 target_method()->set_vtable_index(methodOopDesc::nonvirtual_vtable_index);
267
268 // Static and <init> methods are never in
269 if (target_method()->is_static() || target_method()->name() == vmSymbols::object_initializer_name()) {
270 return false;
271 }
272
273 if (klass->is_final() || target_method()->is_final()) {
274 // a final method never needs a new entry; final methods can be statically
275 // resolved and they have to be present in the vtable only if they override
276 // a super's method, in which case they re-use its entry
277 allocate_new = false;
278 }
279
280 // we need a new entry if there is no superclass
281 if (klass->super() == NULL) {
282 return allocate_new;
283 }
284
285 // private methods always have a new entry in the vtable
286 // specification interpretation since classic has
287 // private methods not overriding
288 if (target_method()->is_private()) {
289 return allocate_new;
290 }
291
292 // search through the vtable and update overridden entries
293 // Since check_signature_loaders acquires SystemDictionary_lock
294 // which can block for gc, once we are in this loop, use handles
295 // For classfiles built with >= jdk7, we now look for transitive overrides
296
297 Symbol* name = target_method()->name();
298 Symbol* signature = target_method()->signature();
299 Handle target_loader(THREAD, _klass->class_loader());
300 Symbol* target_classname = _klass->name();
301 for(int i = 0; i < super_vtable_len; i++) {
302 methodOop super_method = method_at(i);
303 // Check if method name matches
304 if (super_method->name() == name && super_method->signature() == signature) {
305
306 // get super_klass for method_holder for the found method
307 instanceKlass* super_klass = instanceKlass::cast(super_method->method_holder());
308
309 if ((super_klass->is_override(super_method, target_loader, target_classname, THREAD)) ||
310 ((klass->major_version() >= VTABLE_TRANSITIVE_OVERRIDE_VERSION)
311 && ((super_klass = find_transitive_override(super_klass, target_method, i, target_loader,
312 target_classname, THREAD)) != (instanceKlass*)NULL))) {
313 // overriding, so no new entry
314 allocate_new = false;
315
316 if (checkconstraints) {
317 // Override vtable entry if passes loader constraint check
318 // if loader constraint checking requested
319 // No need to visit his super, since he and his super
320 // have already made any needed loader constraints.
321 // Since loader constraints are transitive, it is enough
322 // to link to the first super, and we get all the others.
323 Handle super_loader(THREAD, super_klass->class_loader());
324
325 if (target_loader() != super_loader()) {
326 ResourceMark rm(THREAD);
327 char* failed_type_name =
328 SystemDictionary::check_signature_loaders(signature, target_loader,
329 super_loader, true,
330 CHECK_(false));
331 if (failed_type_name != NULL) {
332 const char* msg = "loader constraint violation: when resolving "
333 "overridden method \"%s\" the class loader (instance"
334 " of %s) of the current class, %s, and its superclass loader "
335 "(instance of %s), have different Class objects for the type "
336 "%s used in the signature";
337 char* sig = target_method()->name_and_sig_as_C_string();
338 const char* loader1 = SystemDictionary::loader_name(target_loader());
339 char* current = _klass->name()->as_C_string();
340 const char* loader2 = SystemDictionary::loader_name(super_loader());
341 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
342 strlen(current) + strlen(loader2) + strlen(failed_type_name);
343 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
344 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2,
345 failed_type_name);
346 THROW_MSG_(vmSymbols::java_lang_LinkageError(), buf, false);
347 }
348 }
349 }
350
351 put_method_at(target_method(), i);
352 target_method()->set_vtable_index(i);
353 #ifndef PRODUCT
354 if (PrintVtables && Verbose) {
355 tty->print("overriding with %s::%s index %d, original flags: ",
356 _klass->internal_name(), (target_method() != NULL) ?
357 target_method()->name()->as_C_string() : "<NULL>", i);
358 super_method->access_flags().print_on(tty);
359 tty->print("overriders flags: ");
360 target_method->access_flags().print_on(tty);
361 tty->cr();
362 }
363 #endif /*PRODUCT*/
364 } else {
365 // allocate_new = true; default. We might override one entry,
366 // but not override another. Once we override one, not need new
367 #ifndef PRODUCT
368 if (PrintVtables && Verbose) {
369 tty->print("NOT overriding with %s::%s index %d, original flags: ",
370 _klass->internal_name(), (target_method() != NULL) ?
371 target_method()->name()->as_C_string() : "<NULL>", i);
372 super_method->access_flags().print_on(tty);
373 tty->print("overriders flags: ");
374 target_method->access_flags().print_on(tty);
375 tty->cr();
376 }
377 #endif /*PRODUCT*/
378 }
379 }
380 }
381 return allocate_new;
382 }
383
384 void klassVtable::put_method_at(methodOop m, int index) {
385 assert(m->is_oop_or_null(), "Not an oop or null");
386 #ifndef PRODUCT
387 if (PrintVtables && Verbose) {
388 ResourceMark rm;
389 tty->print_cr("adding %s::%s at index %d", _klass->internal_name(),
390 (m != NULL) ? m->name()->as_C_string() : "<NULL>", index);
391 }
392 assert(unchecked_method_at(index)->is_oop_or_null(), "Not an oop or null");
393 #endif
394 table()[index].set(m);
395 }
396
397 // Find out if a method "m" with superclass "super", loader "classloader" and
398 // name "classname" needs a new vtable entry. Let P be a class package defined
399 // by "classloader" and "classname".
400 // NOTE: The logic used here is very similar to the one used for computing
401 // the vtables indices for a method. We cannot directly use that function because,
402 // we allocate the instanceKlass at load time, and that requires that the
403 // superclass has been loaded.
404 // However, the vtable entries are filled in at link time, and therefore
405 // the superclass' vtable may not yet have been filled in.
406 bool klassVtable::needs_new_vtable_entry(methodHandle target_method,
407 klassOop super,
408 Handle classloader,
409 Symbol* classname,
410 AccessFlags class_flags,
411 TRAPS) {
412 if ((class_flags.is_final() || target_method()->is_final()) ||
413 // a final method never needs a new entry; final methods can be statically
414 // resolved and they have to be present in the vtable only if they override
415 // a super's method, in which case they re-use its entry
416 (target_method()->is_static()) ||
417 // static methods don't need to be in vtable
418 (target_method()->name() == vmSymbols::object_initializer_name())
419 // <init> is never called dynamically-bound
420 ) {
421 return false;
422 }
423
424 // we need a new entry if there is no superclass
425 if (super == NULL) {
426 return true;
427 }
428
429 // private methods always have a new entry in the vtable
430 // specification interpretation since classic has
431 // private methods not overriding
432 if (target_method()->is_private()) {
433 return true;
434 }
435
436 // search through the super class hierarchy to see if we need
437 // a new entry
438 ResourceMark rm;
439 Symbol* name = target_method()->name();
440 Symbol* signature = target_method()->signature();
441 klassOop k = super;
442 methodOop super_method = NULL;
443 instanceKlass *holder = NULL;
444 methodOop recheck_method = NULL;
445 while (k != NULL) {
446 // lookup through the hierarchy for a method with matching name and sign.
447 super_method = instanceKlass::cast(k)->lookup_method(name, signature);
448 if (super_method == NULL) {
449 break; // we still have to search for a matching miranda method
450 }
451 // get the class holding the matching method
452 // make sure you use that class for is_override
453 instanceKlass* superk = instanceKlass::cast(super_method->method_holder());
454 // we want only instance method matches
455 // pretend private methods are not in the super vtable
456 // since we do override around them: e.g. a.m pub/b.m private/c.m pub,
457 // ignore private, c.m pub does override a.m pub
458 // For classes that were not javac'd together, we also do transitive overriding around
459 // methods that have less accessibility
460 if ((!super_method->is_static()) &&
461 (!super_method->is_private())) {
462 if (superk->is_override(super_method, classloader, classname, THREAD)) {
463 return false;
464 // else keep looking for transitive overrides
465 }
466 }
467
468 // Start with lookup result and continue to search up
469 k = superk->super(); // haven't found an override match yet; continue to look
470 }
471
472 // if the target method is public or protected it may have a matching
473 // miranda method in the super, whose entry it should re-use.
474 // Actually, to handle cases that javac would not generate, we need
475 // this check for all access permissions.
476 instanceKlass *sk = instanceKlass::cast(super);
477 if (sk->has_miranda_methods()) {
478 if (sk->lookup_method_in_all_interfaces(name, signature) != NULL) {
479 return false; // found a matching miranda; we do not need a new entry
480 }
481 }
482 return true; // found no match; we need a new entry
483 }
484
485 // Support for miranda methods
486
487 // get the vtable index of a miranda method with matching "name" and "signature"
488 int klassVtable::index_of_miranda(Symbol* name, Symbol* signature) {
489 // search from the bottom, might be faster
490 for (int i = (length() - 1); i >= 0; i--) {
491 methodOop m = table()[i].method();
492 if (is_miranda_entry_at(i) &&
493 m->name() == name && m->signature() == signature) {
494 return i;
495 }
496 }
497 return methodOopDesc::invalid_vtable_index;
498 }
499
500 // check if an entry is miranda
501 bool klassVtable::is_miranda_entry_at(int i) {
502 methodOop m = method_at(i);
503 klassOop method_holder = m->method_holder();
504 instanceKlass *mhk = instanceKlass::cast(method_holder);
505
506 // miranda methods are interface methods in a class's vtable
507 if (mhk->is_interface()) {
508 assert(m->is_public() && m->is_abstract(), "should be public and abstract");
509 assert(ik()->implements_interface(method_holder) , "this class should implement the interface");
510 assert(is_miranda(m, ik()->methods(), ik()->super()), "should be a miranda_method");
511 return true;
512 }
513 return false;
514 }
515
516 // check if a method is a miranda method, given a class's methods table and it's super
517 // the caller must make sure that the method belongs to an interface implemented by the class
518 bool klassVtable::is_miranda(methodOop m, objArrayOop class_methods, klassOop super) {
519 Symbol* name = m->name();
520 Symbol* signature = m->signature();
521 if (instanceKlass::find_method(class_methods, name, signature) == NULL) {
522 // did not find it in the method table of the current class
523 if (super == NULL) {
524 // super doesn't exist
525 return true;
526 }
527
528 methodOop mo = instanceKlass::cast(super)->lookup_method(name, signature);
529 if (mo == NULL || mo->access_flags().is_private() ) {
530 // super class hierarchy does not implement it or protection is different
531 return true;
532 }
533 }
534
535 return false;
536 }
537
538 void klassVtable::add_new_mirandas_to_list(GrowableArray<methodOop>* list_of_current_mirandas,
539 objArrayOop current_interface_methods,
540 objArrayOop class_methods,
541 klassOop super) {
542 // iterate thru the current interface's method to see if it a miranda
543 int num_methods = current_interface_methods->length();
544 for (int i = 0; i < num_methods; i++) {
545 methodOop im = methodOop(current_interface_methods->obj_at(i));
546 bool is_duplicate = false;
547 int num_of_current_mirandas = list_of_current_mirandas->length();
548 // check for duplicate mirandas in different interfaces we implement
549 for (int j = 0; j < num_of_current_mirandas; j++) {
550 methodOop miranda = list_of_current_mirandas->at(j);
551 if ((im->name() == miranda->name()) &&
552 (im->signature() == miranda->signature())) {
553 is_duplicate = true;
554 break;
555 }
556 }
557
558 if (!is_duplicate) { // we don't want duplicate miranda entries in the vtable
559 if (is_miranda(im, class_methods, super)) { // is it a miranda at all?
560 instanceKlass *sk = instanceKlass::cast(super);
561 // check if it is a duplicate of a super's miranda
562 if (sk->lookup_method_in_all_interfaces(im->name(), im->signature()) == NULL) {
563 list_of_current_mirandas->append(im);
564 }
565 }
566 }
567 }
568 }
569
570 void klassVtable::get_mirandas(GrowableArray<methodOop>* mirandas,
571 klassOop super, objArrayOop class_methods,
572 objArrayOop local_interfaces) {
573 assert((mirandas->length() == 0) , "current mirandas must be 0");
574
575 // iterate thru the local interfaces looking for a miranda
576 int num_local_ifs = local_interfaces->length();
577 for (int i = 0; i < num_local_ifs; i++) {
578 instanceKlass *ik = instanceKlass::cast(klassOop(local_interfaces->obj_at(i)));
579 add_new_mirandas_to_list(mirandas, ik->methods(), class_methods, super);
580 // iterate thru each local's super interfaces
581 objArrayOop super_ifs = ik->transitive_interfaces();
582 int num_super_ifs = super_ifs->length();
583 for (int j = 0; j < num_super_ifs; j++) {
584 instanceKlass *sik = instanceKlass::cast(klassOop(super_ifs->obj_at(j)));
585 add_new_mirandas_to_list(mirandas, sik->methods(), class_methods, super);
586 }
587 }
588 }
589
590 // get number of mirandas
591 int klassVtable::get_num_mirandas(klassOop super, objArrayOop class_methods, objArrayOop local_interfaces) {
592 ResourceMark rm;
593 GrowableArray<methodOop>* mirandas = new GrowableArray<methodOop>(20);
594 get_mirandas(mirandas, super, class_methods, local_interfaces);
595 return mirandas->length();
596 }
597
598 // fill in mirandas
599 void klassVtable::fill_in_mirandas(int& initialized) {
600 ResourceMark rm;
601 GrowableArray<methodOop>* mirandas = new GrowableArray<methodOop>(20);
602 instanceKlass *this_ik = ik();
603 get_mirandas(mirandas, this_ik->super(), this_ik->methods(), this_ik->local_interfaces());
604 int num_mirandas = mirandas->length();
605 for (int i = 0; i < num_mirandas; i++) {
606 put_method_at(mirandas->at(i), initialized);
607 initialized++;
608 }
609 }
610
611 void klassVtable::copy_vtable_to(vtableEntry* start) {
612 Copy::disjoint_words((HeapWord*)table(), (HeapWord*)start, _length * vtableEntry::size());
613 }
614
615 void klassVtable::adjust_method_entries(methodOop* old_methods, methodOop* new_methods,
616 int methods_length, bool * trace_name_printed) {
617 // search the vtable for uses of either obsolete or EMCP methods
618 for (int j = 0; j < methods_length; j++) {
619 methodOop old_method = old_methods[j];
620 methodOop new_method = new_methods[j];
621
622 // In the vast majority of cases we could get the vtable index
623 // by using: old_method->vtable_index()
624 // However, there are rare cases, eg. sun.awt.X11.XDecoratedPeer.getX()
625 // in sun.awt.X11.XFramePeer where methods occur more than once in the
626 // vtable, so, alas, we must do an exhaustive search.
627 for (int index = 0; index < length(); index++) {
628 if (unchecked_method_at(index) == old_method) {
629 put_method_at(new_method, index);
630
631 if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
632 if (!(*trace_name_printed)) {
633 // RC_TRACE_MESG macro has an embedded ResourceMark
634 RC_TRACE_MESG(("adjust: name=%s",
635 Klass::cast(old_method->method_holder())->external_name()));
636 *trace_name_printed = true;
637 }
638 // RC_TRACE macro has an embedded ResourceMark
639 RC_TRACE(0x00100000, ("vtable method update: %s(%s)",
640 new_method->name()->as_C_string(),
641 new_method->signature()->as_C_string()));
642 }
643 }
644 }
645 }
646 }
647
648
649 // Garbage collection
650 void klassVtable::oop_follow_contents() {
651 int len = length();
652 for (int i = 0; i < len; i++) {
653 MarkSweep::mark_and_push(adr_method_at(i));
654 }
655 }
656
657 #ifndef SERIALGC
658 void klassVtable::oop_follow_contents(ParCompactionManager* cm) {
659 int len = length();
660 for (int i = 0; i < len; i++) {
661 PSParallelCompact::mark_and_push(cm, adr_method_at(i));
662 }
663 }
664 #endif // SERIALGC
665
666 void klassVtable::oop_adjust_pointers() {
667 int len = length();
668 for (int i = 0; i < len; i++) {
669 MarkSweep::adjust_pointer(adr_method_at(i));
670 }
671 }
672
673 #ifndef SERIALGC
674 void klassVtable::oop_update_pointers(ParCompactionManager* cm) {
675 const int n = length();
676 for (int i = 0; i < n; i++) {
677 PSParallelCompact::adjust_pointer(adr_method_at(i));
678 }
679 }
680 #endif // SERIALGC
681
682 // Iterators
683 void klassVtable::oop_oop_iterate(OopClosure* blk) {
684 int len = length();
685 for (int i = 0; i < len; i++) {
686 blk->do_oop(adr_method_at(i));
687 }
688 }
689
690 void klassVtable::oop_oop_iterate_m(OopClosure* blk, MemRegion mr) {
691 int len = length();
692 int i;
693 for (i = 0; i < len; i++) {
694 if ((HeapWord*)adr_method_at(i) >= mr.start()) break;
695 }
696 for (; i < len; i++) {
697 oop* adr = adr_method_at(i);
698 if ((HeapWord*)adr < mr.end()) blk->do_oop(adr);
699 }
700 }
701
702 //-----------------------------------------------------------------------------------------
703 // Itable code
704
705 // Initialize a itableMethodEntry
706 void itableMethodEntry::initialize(methodOop m) {
707 if (m == NULL) return;
708
709 _method = m;
710 }
711
712 klassItable::klassItable(instanceKlassHandle klass) {
713 _klass = klass;
714
715 if (klass->itable_length() > 0) {
716 itableOffsetEntry* offset_entry = (itableOffsetEntry*)klass->start_of_itable();
717 if (offset_entry != NULL && offset_entry->interface_klass() != NULL) { // Check that itable is initialized
718 // First offset entry points to the first method_entry
719 intptr_t* method_entry = (intptr_t *)(((address)klass->as_klassOop()) + offset_entry->offset());
720 intptr_t* end = klass->end_of_itable();
721
722 _table_offset = (intptr_t*)offset_entry - (intptr_t*)klass->as_klassOop();
723 _size_offset_table = (method_entry - ((intptr_t*)offset_entry)) / itableOffsetEntry::size();
724 _size_method_table = (end - method_entry) / itableMethodEntry::size();
725 assert(_table_offset >= 0 && _size_offset_table >= 0 && _size_method_table >= 0, "wrong computation");
726 return;
727 }
728 }
729
730 // The length of the itable was either zero, or it has not yet been initialized.
731 _table_offset = 0;
732 _size_offset_table = 0;
733 _size_method_table = 0;
734 }
735
736 // Garbage Collection
737
738 void klassItable::oop_follow_contents() {
739 // offset table
740 itableOffsetEntry* ioe = offset_entry(0);
741 for(int i = 0; i < _size_offset_table; i++) {
742 MarkSweep::mark_and_push((oop*)&ioe->_interface);
743 ioe++;
744 }
745
746 // method table
747 itableMethodEntry* ime = method_entry(0);
748 for(int j = 0; j < _size_method_table; j++) {
749 MarkSweep::mark_and_push((oop*)&ime->_method);
750 ime++;
751 }
752 }
753
754 #ifndef SERIALGC
755 void klassItable::oop_follow_contents(ParCompactionManager* cm) {
756 // offset table
757 itableOffsetEntry* ioe = offset_entry(0);
758 for(int i = 0; i < _size_offset_table; i++) {
759 PSParallelCompact::mark_and_push(cm, (oop*)&ioe->_interface);
760 ioe++;
761 }
762
763 // method table
764 itableMethodEntry* ime = method_entry(0);
765 for(int j = 0; j < _size_method_table; j++) {
766 PSParallelCompact::mark_and_push(cm, (oop*)&ime->_method);
767 ime++;
768 }
769 }
770 #endif // SERIALGC
771
772 void klassItable::oop_adjust_pointers() {
773 // offset table
774 itableOffsetEntry* ioe = offset_entry(0);
775 for(int i = 0; i < _size_offset_table; i++) {
776 MarkSweep::adjust_pointer((oop*)&ioe->_interface);
777 ioe++;
778 }
779
780 // method table
781 itableMethodEntry* ime = method_entry(0);
782 for(int j = 0; j < _size_method_table; j++) {
783 MarkSweep::adjust_pointer((oop*)&ime->_method);
784 ime++;
785 }
786 }
787
788 #ifndef SERIALGC
789 void klassItable::oop_update_pointers(ParCompactionManager* cm) {
790 // offset table
791 itableOffsetEntry* ioe = offset_entry(0);
792 for(int i = 0; i < _size_offset_table; i++) {
793 PSParallelCompact::adjust_pointer((oop*)&ioe->_interface);
794 ioe++;
795 }
796
797 // method table
798 itableMethodEntry* ime = method_entry(0);
799 for(int j = 0; j < _size_method_table; j++) {
800 PSParallelCompact::adjust_pointer((oop*)&ime->_method);
801 ime++;
802 }
803 }
804 #endif // SERIALGC
805
806 // Iterators
807 void klassItable::oop_oop_iterate(OopClosure* blk) {
808 // offset table
809 itableOffsetEntry* ioe = offset_entry(0);
810 for(int i = 0; i < _size_offset_table; i++) {
811 blk->do_oop((oop*)&ioe->_interface);
812 ioe++;
813 }
814
815 // method table
816 itableMethodEntry* ime = method_entry(0);
817 for(int j = 0; j < _size_method_table; j++) {
818 blk->do_oop((oop*)&ime->_method);
819 ime++;
820 }
821 }
822
823 void klassItable::oop_oop_iterate_m(OopClosure* blk, MemRegion mr) {
824 // offset table
825 itableOffsetEntry* ioe = offset_entry(0);
826 for(int i = 0; i < _size_offset_table; i++) {
827 oop* adr = (oop*)&ioe->_interface;
828 if (mr.contains(adr)) blk->do_oop(adr);
829 ioe++;
830 }
831
832 // method table
833 itableMethodEntry* ime = method_entry(0);
834 for(int j = 0; j < _size_method_table; j++) {
835 oop* adr = (oop*)&ime->_method;
836 if (mr.contains(adr)) blk->do_oop(adr);
837 ime++;
838 }
839 }
840
841
842 static int initialize_count = 0;
843
844 // Initialization
845 void klassItable::initialize_itable(bool checkconstraints, TRAPS) {
846 // Cannot be setup doing bootstrapping, interfaces don't have
847 // itables, and klass with only ones entry have empty itables
848 if (Universe::is_bootstrapping() ||
849 _klass->is_interface() ||
850 _klass->itable_length() == itableOffsetEntry::size()) return;
851
852 // There's alway an extra itable entry so we can null-terminate it.
853 guarantee(size_offset_table() >= 1, "too small");
854 int num_interfaces = size_offset_table() - 1;
855 if (num_interfaces > 0) {
856 if (TraceItables) tty->print_cr("%3d: Initializing itables for %s", ++initialize_count,
857 _klass->name()->as_C_string());
858
859
860 // Iterate through all interfaces
861 int i;
862 for(i = 0; i < num_interfaces; i++) {
863 itableOffsetEntry* ioe = offset_entry(i);
864 KlassHandle interf_h (THREAD, ioe->interface_klass());
865 assert(interf_h() != NULL && ioe->offset() != 0, "bad offset entry in itable");
866 initialize_itable_for_interface(ioe->offset(), interf_h, checkconstraints, CHECK);
867 }
868
869 }
870 // Check that the last entry is empty
871 itableOffsetEntry* ioe = offset_entry(size_offset_table() - 1);
872 guarantee(ioe->interface_klass() == NULL && ioe->offset() == 0, "terminator entry missing");
873 }
874
875
876 void klassItable::initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS) {
877 objArrayHandle methods(THREAD, instanceKlass::cast(interf_h())->methods());
878 int nof_methods = methods()->length();
879 HandleMark hm;
880 KlassHandle klass = _klass;
881 assert(nof_methods > 0, "at least one method must exist for interface to be in vtable");
882 Handle interface_loader (THREAD, instanceKlass::cast(interf_h())->class_loader());
883 int ime_num = 0;
884
885 // Skip first methodOop if it is a class initializer
886 int i = ((methodOop)methods()->obj_at(0))->is_static_initializer() ? 1 : 0;
887
888 // m, method_name, method_signature, klass reset each loop so they
889 // don't need preserving across check_signature_loaders call
890 // methods needs a handle in case of gc from check_signature_loaders
891 for(; i < nof_methods; i++) {
892 methodOop m = (methodOop)methods()->obj_at(i);
893 Symbol* method_name = m->name();
894 Symbol* method_signature = m->signature();
895
896 // This is same code as in Linkresolver::lookup_instance_method_in_klasses
897 methodOop target = klass->uncached_lookup_method(method_name, method_signature);
898 while (target != NULL && target->is_static()) {
899 // continue with recursive lookup through the superclass
900 klassOop super = Klass::cast(target->method_holder())->super();
901 target = (super == NULL) ? methodOop(NULL) : Klass::cast(super)->uncached_lookup_method(method_name, method_signature);
902 }
903 if (target == NULL || !target->is_public() || target->is_abstract()) {
904 // Entry do not resolve. Leave it empty
905 } else {
906 // Entry did resolve, check loader constraints before initializing
907 // if checkconstraints requested
908 methodHandle target_h (THREAD, target); // preserve across gc
909 if (checkconstraints) {
910 Handle method_holder_loader (THREAD, instanceKlass::cast(target->method_holder())->class_loader());
911 if (method_holder_loader() != interface_loader()) {
912 ResourceMark rm(THREAD);
913 char* failed_type_name =
914 SystemDictionary::check_signature_loaders(method_signature,
915 method_holder_loader,
916 interface_loader,
917 true, CHECK);
918 if (failed_type_name != NULL) {
919 const char* msg = "loader constraint violation in interface "
920 "itable initialization: when resolving method \"%s\" the class"
921 " loader (instance of %s) of the current class, %s, "
922 "and the class loader (instance of %s) for interface "
923 "%s have different Class objects for the type %s "
924 "used in the signature";
925 char* sig = target_h()->name_and_sig_as_C_string();
926 const char* loader1 = SystemDictionary::loader_name(method_holder_loader());
927 char* current = klass->name()->as_C_string();
928 const char* loader2 = SystemDictionary::loader_name(interface_loader());
929 char* iface = instanceKlass::cast(interf_h())->name()->as_C_string();
930 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
931 strlen(current) + strlen(loader2) + strlen(iface) +
932 strlen(failed_type_name);
933 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
934 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2,
935 iface, failed_type_name);
936 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
937 }
938 }
939 }
940
941 // ime may have moved during GC so recalculate address
942 itableOffsetEntry::method_entry(_klass(), method_table_offset)[ime_num].initialize(target_h());
943 }
944 // Progress to next entry
945 ime_num++;
946 }
947 }
948
949 // Update entry for specific methodOop
950 void klassItable::initialize_with_method(methodOop m) {
951 itableMethodEntry* ime = method_entry(0);
952 for(int i = 0; i < _size_method_table; i++) {
953 if (ime->method() == m) {
954 ime->initialize(m);
955 }
956 ime++;
957 }
958 }
959
960 void klassItable::adjust_method_entries(methodOop* old_methods, methodOop* new_methods,
961 int methods_length, bool * trace_name_printed) {
962 // search the itable for uses of either obsolete or EMCP methods
963 for (int j = 0; j < methods_length; j++) {
964 methodOop old_method = old_methods[j];
965 methodOop new_method = new_methods[j];
966 itableMethodEntry* ime = method_entry(0);
967
968 // The itable can describe more than one interface and the same
969 // method signature can be specified by more than one interface.
970 // This means we have to do an exhaustive search to find all the
971 // old_method references.
972 for (int i = 0; i < _size_method_table; i++) {
973 if (ime->method() == old_method) {
974 ime->initialize(new_method);
975
976 if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
977 if (!(*trace_name_printed)) {
978 // RC_TRACE_MESG macro has an embedded ResourceMark
979 RC_TRACE_MESG(("adjust: name=%s",
980 Klass::cast(old_method->method_holder())->external_name()));
981 *trace_name_printed = true;
982 }
983 // RC_TRACE macro has an embedded ResourceMark
984 RC_TRACE(0x00200000, ("itable method update: %s(%s)",
985 new_method->name()->as_C_string(),
986 new_method->signature()->as_C_string()));
987 }
988 break;
989 }
990 ime++;
991 }
992 }
993 }
994
995
996 // Setup
997 class InterfaceVisiterClosure : public StackObj {
998 public:
999 virtual void doit(klassOop intf, int method_count) = 0;
1000 };
1001
1002 // Visit all interfaces with at-least one method (excluding <clinit>)
1003 void visit_all_interfaces(objArrayOop transitive_intf, InterfaceVisiterClosure *blk) {
1004 // Handle array argument
1005 for(int i = 0; i < transitive_intf->length(); i++) {
1006 klassOop intf = (klassOop)transitive_intf->obj_at(i);
1007 assert(Klass::cast(intf)->is_interface(), "sanity check");
1008
1009 // Find no. of methods excluding a <clinit>
1010 int method_count = instanceKlass::cast(intf)->methods()->length();
1011 if (method_count > 0) {
1012 methodOop m = (methodOop)instanceKlass::cast(intf)->methods()->obj_at(0);
1013 assert(m != NULL && m->is_method(), "sanity check");
1014 if (m->name() == vmSymbols::object_initializer_name()) {
1015 method_count--;
1016 }
1017 }
1018
1019 // Only count interfaces with at least one method
1020 if (method_count > 0) {
1021 blk->doit(intf, method_count);
1022 }
1023 }
1024 }
1025
1026 class CountInterfacesClosure : public InterfaceVisiterClosure {
1027 private:
1028 int _nof_methods;
1029 int _nof_interfaces;
1030 public:
1031 CountInterfacesClosure() { _nof_methods = 0; _nof_interfaces = 0; }
1032
1033 int nof_methods() const { return _nof_methods; }
1034 int nof_interfaces() const { return _nof_interfaces; }
1035
1036 void doit(klassOop intf, int method_count) { _nof_methods += method_count; _nof_interfaces++; }
1037 };
1038
1039 class SetupItableClosure : public InterfaceVisiterClosure {
1040 private:
1041 itableOffsetEntry* _offset_entry;
1042 itableMethodEntry* _method_entry;
1043 address _klass_begin;
1044 public:
1045 SetupItableClosure(address klass_begin, itableOffsetEntry* offset_entry, itableMethodEntry* method_entry) {
1046 _klass_begin = klass_begin;
1047 _offset_entry = offset_entry;
1048 _method_entry = method_entry;
1049 }
1050
1051 itableMethodEntry* method_entry() const { return _method_entry; }
1052
1053 void doit(klassOop intf, int method_count) {
1054 int offset = ((address)_method_entry) - _klass_begin;
1055 _offset_entry->initialize(intf, offset);
1056 _offset_entry++;
1057 _method_entry += method_count;
1058 }
1059 };
1060
1061 int klassItable::compute_itable_size(objArrayHandle transitive_interfaces) {
1062 // Count no of interfaces and total number of interface methods
1063 CountInterfacesClosure cic;
1064 visit_all_interfaces(transitive_interfaces(), &cic);
1065
1066 // There's alway an extra itable entry so we can null-terminate it.
1067 int itable_size = calc_itable_size(cic.nof_interfaces() + 1, cic.nof_methods());
1068
1069 // Statistics
1070 update_stats(itable_size * HeapWordSize);
1071
1072 return itable_size;
1073 }
1074
1075
1076 // Fill out offset table and interface klasses into the itable space
1077 void klassItable::setup_itable_offset_table(instanceKlassHandle klass) {
1078 if (klass->itable_length() == 0) return;
1079 assert(!klass->is_interface(), "Should have zero length itable");
1080
1081 // Count no of interfaces and total number of interface methods
1082 CountInterfacesClosure cic;
1083 visit_all_interfaces(klass->transitive_interfaces(), &cic);
1084 int nof_methods = cic.nof_methods();
1085 int nof_interfaces = cic.nof_interfaces();
1086
1087 // Add one extra entry so we can null-terminate the table
1088 nof_interfaces++;
1089
1090 assert(compute_itable_size(objArrayHandle(klass->transitive_interfaces())) ==
1091 calc_itable_size(nof_interfaces, nof_methods),
1092 "mismatch calculation of itable size");
1093
1094 // Fill-out offset table
1095 itableOffsetEntry* ioe = (itableOffsetEntry*)klass->start_of_itable();
1096 itableMethodEntry* ime = (itableMethodEntry*)(ioe + nof_interfaces);
1097 intptr_t* end = klass->end_of_itable();
1098 assert((oop*)(ime + nof_methods) <= (oop*)klass->start_of_nonstatic_oop_maps(), "wrong offset calculation (1)");
1099 assert((oop*)(end) == (oop*)(ime + nof_methods), "wrong offset calculation (2)");
1100
1101 // Visit all interfaces and initialize itable offset table
1102 SetupItableClosure sic((address)klass->as_klassOop(), ioe, ime);
1103 visit_all_interfaces(klass->transitive_interfaces(), &sic);
1104
1105 #ifdef ASSERT
1106 ime = sic.method_entry();
1107 oop* v = (oop*) klass->end_of_itable();
1108 assert( (oop*)(ime) == v, "wrong offset calculation (2)");
1109 #endif
1110 }
1111
1112
1113 // m must be a method in an interface
1114 int klassItable::compute_itable_index(methodOop m) {
1115 klassOop intf = m->method_holder();
1116 assert(instanceKlass::cast(intf)->is_interface(), "sanity check");
1117 objArrayOop methods = instanceKlass::cast(intf)->methods();
1118 int index = 0;
1119 while(methods->obj_at(index) != m) {
1120 index++;
1121 assert(index < methods->length(), "should find index for resolve_invoke");
1122 }
1123 // Adjust for <clinit>, which is left out of table if first method
1124 if (methods->length() > 0 && ((methodOop)methods->obj_at(0))->is_static_initializer()) {
1125 index--;
1126 }
1127 return index;
1128 }
1129
1130
1131 // inverse to compute_itable_index
1132 methodOop klassItable::method_for_itable_index(klassOop intf, int itable_index) {
1133 assert(instanceKlass::cast(intf)->is_interface(), "sanity check");
1134 objArrayOop methods = instanceKlass::cast(intf)->methods();
1135
1136 int index = itable_index;
1137 // Adjust for <clinit>, which is left out of table if first method
1138 if (methods->length() > 0 && ((methodOop)methods->obj_at(0))->is_static_initializer()) {
1139 index++;
1140 }
1141
1142 if (itable_index < 0 || index >= methods->length())
1143 return NULL; // help caller defend against bad indexes
1144
1145 methodOop m = (methodOop)methods->obj_at(index);
1146 assert(compute_itable_index(m) == itable_index, "correct inverse");
1147
1148 return m;
1149 }
1150
1151 void klassVtable::verify(outputStream* st, bool forced) {
1152 // make sure table is initialized
1153 if (!Universe::is_fully_initialized()) return;
1154 #ifndef PRODUCT
1155 // avoid redundant verifies
1156 if (!forced && _verify_count == Universe::verify_count()) return;
1157 _verify_count = Universe::verify_count();
1158 #endif
1159 oop* end_of_obj = (oop*)_klass() + _klass()->size();
1160 oop* end_of_vtable = (oop *)&table()[_length];
1161 if (end_of_vtable > end_of_obj) {
1162 fatal(err_msg("klass %s: klass object too short (vtable extends beyond "
1163 "end)", _klass->internal_name()));
1164 }
1165
1166 for (int i = 0; i < _length; i++) table()[i].verify(this, st);
1167 // verify consistency with superKlass vtable
1168 klassOop super = _klass->super();
1169 if (super != NULL) {
1170 instanceKlass* sk = instanceKlass::cast(super);
1171 klassVtable* vt = sk->vtable();
1172 for (int i = 0; i < vt->length(); i++) {
1173 verify_against(st, vt, i);
1174 }
1175 }
1176 }
1177
1178 void klassVtable::verify_against(outputStream* st, klassVtable* vt, int index) {
1179 vtableEntry* vte = &vt->table()[index];
1180 if (vte->method()->name() != table()[index].method()->name() ||
1181 vte->method()->signature() != table()[index].method()->signature()) {
1182 fatal("mismatched name/signature of vtable entries");
1183 }
1184 }
1185
1186 #ifndef PRODUCT
1187 void klassVtable::print() {
1188 ResourceMark rm;
1189 tty->print("klassVtable for klass %s (length %d):\n", _klass->internal_name(), length());
1190 for (int i = 0; i < length(); i++) {
1191 table()[i].print();
1192 tty->cr();
1193 }
1194 }
1195 #endif
1196
1197 void vtableEntry::verify(klassVtable* vt, outputStream* st) {
1198 NOT_PRODUCT(FlagSetting fs(IgnoreLockingAssertions, true));
1199 assert(method() != NULL, "must have set method");
1200 method()->verify();
1201 // we sub_type, because it could be a miranda method
1202 if (!vt->klass()->is_subtype_of(method()->method_holder())) {
1203 #ifndef PRODUCT
1204 print();
1205 #endif
1206 fatal(err_msg("vtableEntry " PTR_FORMAT ": method is from subclass", this));
1207 }
1208 }
1209
1210 #ifndef PRODUCT
1211
1212 void vtableEntry::print() {
1213 ResourceMark rm;
1214 tty->print("vtableEntry %s: ", method()->name()->as_C_string());
1215 if (Verbose) {
1216 tty->print("m %#lx ", (address)method());
1217 }
1218 }
1219
1220 class VtableStats : AllStatic {
1221 public:
1222 static int no_klasses; // # classes with vtables
1223 static int no_array_klasses; // # array classes
1224 static int no_instance_klasses; // # instanceKlasses
1225 static int sum_of_vtable_len; // total # of vtable entries
1226 static int sum_of_array_vtable_len; // total # of vtable entries in array klasses only
1227 static int fixed; // total fixed overhead in bytes
1228 static int filler; // overhead caused by filler bytes
1229 static int entries; // total bytes consumed by vtable entries
1230 static int array_entries; // total bytes consumed by array vtable entries
1231
1232 static void do_class(klassOop k) {
1233 Klass* kl = k->klass_part();
1234 klassVtable* vt = kl->vtable();
1235 if (vt == NULL) return;
1236 no_klasses++;
1237 if (kl->oop_is_instance()) {
1238 no_instance_klasses++;
1239 kl->array_klasses_do(do_class);
1240 }
1241 if (kl->oop_is_array()) {
1242 no_array_klasses++;
1243 sum_of_array_vtable_len += vt->length();
1244 }
1245 sum_of_vtable_len += vt->length();
1246 }
1247
1248 static void compute() {
1249 SystemDictionary::classes_do(do_class);
1250 fixed = no_klasses * oopSize; // vtable length
1251 // filler size is a conservative approximation
1252 filler = oopSize * (no_klasses - no_instance_klasses) * (sizeof(instanceKlass) - sizeof(arrayKlass) - 1);
1253 entries = sizeof(vtableEntry) * sum_of_vtable_len;
1254 array_entries = sizeof(vtableEntry) * sum_of_array_vtable_len;
1255 }
1256 };
1257
1258 int VtableStats::no_klasses = 0;
1259 int VtableStats::no_array_klasses = 0;
1260 int VtableStats::no_instance_klasses = 0;
1261 int VtableStats::sum_of_vtable_len = 0;
1262 int VtableStats::sum_of_array_vtable_len = 0;
1263 int VtableStats::fixed = 0;
1264 int VtableStats::filler = 0;
1265 int VtableStats::entries = 0;
1266 int VtableStats::array_entries = 0;
1267
1268 void klassVtable::print_statistics() {
1269 ResourceMark rm;
1270 HandleMark hm;
1271 VtableStats::compute();
1272 tty->print_cr("vtable statistics:");
1273 tty->print_cr("%6d classes (%d instance, %d array)", VtableStats::no_klasses, VtableStats::no_instance_klasses, VtableStats::no_array_klasses);
1274 int total = VtableStats::fixed + VtableStats::filler + VtableStats::entries;
1275 tty->print_cr("%6d bytes fixed overhead (refs + vtable object header)", VtableStats::fixed);
1276 tty->print_cr("%6d bytes filler overhead", VtableStats::filler);
1277 tty->print_cr("%6d bytes for vtable entries (%d for arrays)", VtableStats::entries, VtableStats::array_entries);
1278 tty->print_cr("%6d bytes total", total);
1279 }
1280
1281 bool klassVtable::check_no_old_entries() {
1282 // Check that there really is no entry
1283 for (int i = 0; i < length(); i++) {
1284 methodOop m = unchecked_method_at(i);
1285 if (m != NULL) {
1286 if (m->is_old()) {
1287 return false;
1288 }
1289 }
1290 }
1291 return true;
1292 }
1293
1294 void klassVtable::dump_vtable() {
1295 tty->print_cr("vtable dump --");
1296 for (int i = 0; i < length(); i++) {
1297 methodOop m = unchecked_method_at(i);
1298 if (m != NULL) {
1299 tty->print(" (%5d) ", i);
1300 m->access_flags().print_on(tty);
1301 tty->print(" -- ");
1302 m->print_name(tty);
1303 tty->cr();
1304 }
1305 }
1306 }
1307
1308 int klassItable::_total_classes; // Total no. of classes with itables
1309 long klassItable::_total_size; // Total no. of bytes used for itables
1310
1311 void klassItable::print_statistics() {
1312 tty->print_cr("itable statistics:");
1313 tty->print_cr("%6d classes with itables", _total_classes);
1314 tty->print_cr("%6d K uses for itables (average by class: %d bytes)", _total_size / K, _total_size / _total_classes);
1315 }
1316
1317 #endif // PRODUCT