1 /*
2 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/systemDictionary.hpp"
27 #include "classfile/vmSymbols.hpp"
28 #include "gc_implementation/shared/markSweep.inline.hpp"
29 #include "memory/gcLocker.hpp"
30 #include "memory/resourceArea.hpp"
31 #include "memory/universe.inline.hpp"
32 #include "oops/instanceKlass.hpp"
33 #include "oops/klassVtable.hpp"
34 #include "oops/method.hpp"
35 #include "oops/objArrayOop.hpp"
36 #include "oops/oop.inline.hpp"
37 #include "prims/jvmtiRedefineClassesTrace.hpp"
38 #include "runtime/arguments.hpp"
39 #include "runtime/handles.inline.hpp"
40 #include "utilities/copy.hpp"
41
42 inline InstanceKlass* klassVtable::ik() const {
43 Klass* k = _klass();
44 assert(k->oop_is_instance(), "not an InstanceKlass");
45 return (InstanceKlass*)k;
46 }
47
48
49 // this function computes the vtable size (including the size needed for miranda
50 // methods) and the number of miranda methods in this class
51 // Note on Miranda methods: Let's say there is a class C that implements
52 // interface I. Let's say there is a method m in I that neither C nor any
53 // of its super classes implement (i.e there is no method of any access, with
54 // the same name and signature as m), then m is a Miranda method which is
55 // entered as a public abstract method in C's vtable. From then on it should
56 // treated as any other public method in C for method over-ride purposes.
57 void klassVtable::compute_vtable_size_and_num_mirandas(
58 int* vtable_length_ret, int* num_new_mirandas,
59 GrowableArray<Method*>* all_mirandas, Klass* super,
60 Array<Method*>* methods, AccessFlags class_flags,
61 Handle classloader, Symbol* classname, Array<Klass*>* local_interfaces,
62 TRAPS) {
63 No_Safepoint_Verifier nsv;
64
65 // set up default result values
66 int vtable_length = 0;
67
68 // start off with super's vtable length
69 InstanceKlass* sk = (InstanceKlass*)super;
70 vtable_length = super == NULL ? 0 : sk->vtable_length();
71
72 // go thru each method in the methods table to see if it needs a new entry
73 int len = methods->length();
74 for (int i = 0; i < len; i++) {
75 assert(methods->at(i)->is_method(), "must be a Method*");
76 methodHandle mh(THREAD, methods->at(i));
77
78 if (needs_new_vtable_entry(mh, super, classloader, classname, class_flags, THREAD)) {
79 vtable_length += vtableEntry::size(); // we need a new entry
80 }
81 }
82
83 GrowableArray<Method*> new_mirandas(20);
84 // compute the number of mirandas methods that must be added to the end
85 get_mirandas(&new_mirandas, all_mirandas, super, methods, local_interfaces);
86 *num_new_mirandas = new_mirandas.length();
87
88 vtable_length += *num_new_mirandas * vtableEntry::size();
89
90 if (Universe::is_bootstrapping() && vtable_length == 0) {
91 // array classes don't have their superclass set correctly during
92 // bootstrapping
93 vtable_length = Universe::base_vtable_size();
94 }
95
96 if (super == NULL && !Universe::is_bootstrapping() &&
97 vtable_length != Universe::base_vtable_size()) {
98 // Someone is attempting to redefine java.lang.Object incorrectly. The
99 // only way this should happen is from
100 // SystemDictionary::resolve_from_stream(), which will detect this later
101 // and throw a security exception. So don't assert here to let
102 // the exception occur.
103 vtable_length = Universe::base_vtable_size();
104 }
105 assert(super != NULL || vtable_length == Universe::base_vtable_size(),
106 "bad vtable size for class Object");
107 assert(vtable_length % vtableEntry::size() == 0, "bad vtable length");
108 assert(vtable_length >= Universe::base_vtable_size(), "vtable too small");
109
110 *vtable_length_ret = vtable_length;
111 }
112
113 int klassVtable::index_of(Method* m, int len) const {
114 assert(m->has_vtable_index(), "do not ask this of non-vtable methods");
115 return m->vtable_index();
116 }
117
118 int klassVtable::initialize_from_super(KlassHandle super) {
119 if (super.is_null()) {
120 return 0;
121 } else {
122 // copy methods from superKlass
123 // can't inherit from array class, so must be InstanceKlass
124 assert(super->oop_is_instance(), "must be instance klass");
125 InstanceKlass* sk = (InstanceKlass*)super();
126 klassVtable* superVtable = sk->vtable();
127 assert(superVtable->length() <= _length, "vtable too short");
128 #ifdef ASSERT
129 superVtable->verify(tty, true);
130 #endif
131 superVtable->copy_vtable_to(table());
132 #ifndef PRODUCT
133 if (PrintVtables && Verbose) {
134 ResourceMark rm;
135 tty->print_cr("copy vtable from %s to %s size %d", sk->internal_name(), klass()->internal_name(), _length);
136 }
137 #endif
138 return superVtable->length();
139 }
140 }
141
142 // Revised lookup semantics introduced 1.3 (Kestral beta)
143 void klassVtable::initialize_vtable(bool checkconstraints, TRAPS) {
144
145 // Note: Arrays can have intermediate array supers. Use java_super to skip them.
146 KlassHandle super (THREAD, klass()->java_super());
147 int nofNewEntries = 0;
148
149
150 if (PrintVtables && !klass()->oop_is_array()) {
151 ResourceMark rm(THREAD);
152 tty->print_cr("Initializing: %s", _klass->name()->as_C_string());
153 }
154
155 #ifdef ASSERT
156 oop* end_of_obj = (oop*)_klass() + _klass()->size();
157 oop* end_of_vtable = (oop*)&table()[_length];
158 assert(end_of_vtable <= end_of_obj, "vtable extends beyond end");
159 #endif
160
161 if (Universe::is_bootstrapping()) {
162 // just clear everything
163 for (int i = 0; i < _length; i++) table()[i].clear();
164 return;
165 }
166
167 int super_vtable_len = initialize_from_super(super);
168 if (klass()->oop_is_array()) {
169 assert(super_vtable_len == _length, "arrays shouldn't introduce new methods");
170 } else {
171 assert(_klass->oop_is_instance(), "must be InstanceKlass");
172
173 Array<Method*>* methods = ik()->methods();
174 int len = methods->length();
175 int initialized = super_vtable_len;
176
177 // update_inherited_vtable can stop for gc - ensure using handles
178 for (int i = 0; i < len; i++) {
179 HandleMark hm(THREAD);
180 assert(methods->at(i)->is_method(), "must be a Method*");
181 methodHandle mh(THREAD, methods->at(i));
182
183 bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, checkconstraints, CHECK);
184
185 if (needs_new_entry) {
186 put_method_at(mh(), initialized);
187 mh()->set_vtable_index(initialized); // set primary vtable index
188 initialized++;
189 }
190 }
191
192 // add miranda methods; it will also update the value of initialized
193 fill_in_mirandas(&initialized);
194
195 // In class hierarchies where the accessibility is not increasing (i.e., going from private ->
196 // package_private -> publicprotected), the vtable might actually be smaller than our initial
197 // calculation.
198 assert(initialized <= _length, "vtable initialization failed");
199 for(;initialized < _length; initialized++) {
200 put_method_at(NULL, initialized);
201 }
202 NOT_PRODUCT(verify(tty, true));
203 }
204 }
205
206 // Called for cases where a method does not override its superclass' vtable entry
207 // For bytecodes not produced by javac together it is possible that a method does not override
208 // the superclass's method, but might indirectly override a super-super class's vtable entry
209 // If none found, return a null superk, else return the superk of the method this does override
210 InstanceKlass* klassVtable::find_transitive_override(InstanceKlass* initialsuper, methodHandle target_method,
211 int vtable_index, Handle target_loader, Symbol* target_classname, Thread * THREAD) {
212 InstanceKlass* superk = initialsuper;
213 while (superk != NULL && superk->super() != NULL) {
214 InstanceKlass* supersuperklass = InstanceKlass::cast(superk->super());
215 klassVtable* ssVtable = supersuperklass->vtable();
216 if (vtable_index < ssVtable->length()) {
217 Method* super_method = ssVtable->method_at(vtable_index);
218 #ifndef PRODUCT
219 Symbol* name= target_method()->name();
220 Symbol* signature = target_method()->signature();
221 assert(super_method->name() == name && super_method->signature() == signature, "vtable entry name/sig mismatch");
222 #endif
223 if (supersuperklass->is_override(super_method, target_loader, target_classname, THREAD)) {
224 #ifndef PRODUCT
225 if (PrintVtables && Verbose) {
226 ResourceMark rm(THREAD);
227 tty->print("transitive overriding superclass %s with %s::%s index %d, original flags: ",
228 supersuperklass->internal_name(),
229 _klass->internal_name(), (target_method() != NULL) ?
230 target_method()->name()->as_C_string() : "<NULL>", vtable_index);
231 super_method->access_flags().print_on(tty);
232 tty->print("overriders flags: ");
233 target_method->access_flags().print_on(tty);
234 tty->cr();
235 }
236 #endif /*PRODUCT*/
237 break; // return found superk
238 }
239 } else {
240 // super class has no vtable entry here, stop transitive search
241 superk = (InstanceKlass*)NULL;
242 break;
243 }
244 // if no override found yet, continue to search up
245 superk = InstanceKlass::cast(superk->super());
246 }
247
248 return superk;
249 }
250
251 // Update child's copy of super vtable for overrides
252 // OR return true if a new vtable entry is required
253 // Only called for InstanceKlass's, i.e. not for arrays
254 // If that changed, could not use _klass as handle for klass
255 bool klassVtable::update_inherited_vtable(InstanceKlass* klass, methodHandle target_method, int super_vtable_len,
256 bool checkconstraints, TRAPS) {
257 ResourceMark rm;
258 bool allocate_new = true;
259 assert(klass->oop_is_instance(), "must be InstanceKlass");
260 assert(klass == target_method()->method_holder(), "caller resp.");
261
262 // Initialize the method's vtable index to "nonvirtual".
263 // If we allocate a vtable entry, we will update it to a non-negative number.
264 target_method()->set_vtable_index(Method::nonvirtual_vtable_index);
265
266 // Static and <init> methods are never in
267 if (target_method()->is_static() || target_method()->name() == vmSymbols::object_initializer_name()) {
268 return false;
269 }
270
271 if (target_method->is_final_method(klass->access_flags())) {
272 // a final method never needs a new entry; final methods can be statically
273 // resolved and they have to be present in the vtable only if they override
274 // a super's method, in which case they re-use its entry
275 allocate_new = false;
276 } else if (klass->is_interface()) {
277 allocate_new = false; // see note below in needs_new_vtable_entry
278 // An interface never allocates new vtable slots, only inherits old ones.
279 // This method will either be assigned its own itable index later,
280 // or be assigned an inherited vtable index in the loop below.
281 target_method()->set_vtable_index(Method::pending_itable_index);
282 }
283
284 // we need a new entry if there is no superclass
285 if (klass->super() == NULL) {
286 return allocate_new;
287 }
288
289 // private methods always have a new entry in the vtable
290 // specification interpretation since classic has
291 // private methods not overriding
292 if (target_method()->is_private()) {
293 return allocate_new;
294 }
295
296 // search through the vtable and update overridden entries
297 // Since check_signature_loaders acquires SystemDictionary_lock
298 // which can block for gc, once we are in this loop, use handles
299 // For classfiles built with >= jdk7, we now look for transitive overrides
300
301 Symbol* name = target_method()->name();
302 Symbol* signature = target_method()->signature();
303 Handle target_loader(THREAD, _klass()->class_loader());
304 Symbol* target_classname = _klass->name();
305 for(int i = 0; i < super_vtable_len; i++) {
306 Method* super_method = method_at(i);
307 // Check if method name matches
308 if (super_method->name() == name && super_method->signature() == signature) {
309
310 // get super_klass for method_holder for the found method
311 InstanceKlass* super_klass = super_method->method_holder();
312
313 if ((super_klass->is_override(super_method, target_loader, target_classname, THREAD)) ||
314 ((klass->major_version() >= VTABLE_TRANSITIVE_OVERRIDE_VERSION)
315 && ((super_klass = find_transitive_override(super_klass, target_method, i, target_loader,
316 target_classname, THREAD)) != (InstanceKlass*)NULL))) {
317 // overriding, so no new entry
318 allocate_new = false;
319
320 if (checkconstraints) {
321 // Override vtable entry if passes loader constraint check
322 // if loader constraint checking requested
323 // No need to visit his super, since he and his super
324 // have already made any needed loader constraints.
325 // Since loader constraints are transitive, it is enough
326 // to link to the first super, and we get all the others.
327 Handle super_loader(THREAD, super_klass->class_loader());
328
329 if (target_loader() != super_loader()) {
330 ResourceMark rm(THREAD);
331 Symbol* failed_type_symbol =
332 SystemDictionary::check_signature_loaders(signature, target_loader,
333 super_loader, true,
334 CHECK_(false));
335 if (failed_type_symbol != NULL) {
336 const char* msg = "loader constraint violation: when resolving "
337 "overridden method \"%s\" the class loader (instance"
338 " of %s) of the current class, %s, and its superclass loader "
339 "(instance of %s), have different Class objects for the type "
340 "%s used in the signature";
341 char* sig = target_method()->name_and_sig_as_C_string();
342 const char* loader1 = SystemDictionary::loader_name(target_loader());
343 char* current = _klass->name()->as_C_string();
344 const char* loader2 = SystemDictionary::loader_name(super_loader());
345 char* failed_type_name = failed_type_symbol->as_C_string();
346 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
347 strlen(current) + strlen(loader2) + strlen(failed_type_name);
348 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
349 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2,
350 failed_type_name);
351 THROW_MSG_(vmSymbols::java_lang_LinkageError(), buf, false);
352 }
353 }
354 }
355
356 put_method_at(target_method(), i);
357 target_method()->set_vtable_index(i);
358 #ifndef PRODUCT
359 if (PrintVtables && Verbose) {
360 tty->print("overriding with %s::%s index %d, original flags: ",
361 _klass->internal_name(), (target_method() != NULL) ?
362 target_method()->name()->as_C_string() : "<NULL>", i);
363 super_method->access_flags().print_on(tty);
364 tty->print("overriders flags: ");
365 target_method->access_flags().print_on(tty);
366 tty->cr();
367 }
368 #endif /*PRODUCT*/
369 } else {
370 // allocate_new = true; default. We might override one entry,
371 // but not override another. Once we override one, not need new
372 #ifndef PRODUCT
373 if (PrintVtables && Verbose) {
374 tty->print("NOT overriding with %s::%s index %d, original flags: ",
375 _klass->internal_name(), (target_method() != NULL) ?
376 target_method()->name()->as_C_string() : "<NULL>", i);
377 super_method->access_flags().print_on(tty);
378 tty->print("overriders flags: ");
379 target_method->access_flags().print_on(tty);
380 tty->cr();
381 }
382 #endif /*PRODUCT*/
383 }
384 }
385 }
386 return allocate_new;
387 }
388
389 void klassVtable::put_method_at(Method* m, int index) {
390 #ifndef PRODUCT
391 if (PrintVtables && Verbose) {
392 ResourceMark rm;
393 tty->print_cr("adding %s::%s at index %d", _klass->internal_name(),
394 (m != NULL) ? m->name()->as_C_string() : "<NULL>", index);
395 }
396 #endif
397 table()[index].set(m);
398 }
399
400 // Find out if a method "m" with superclass "super", loader "classloader" and
401 // name "classname" needs a new vtable entry. Let P be a class package defined
402 // by "classloader" and "classname".
403 // NOTE: The logic used here is very similar to the one used for computing
404 // the vtables indices for a method. We cannot directly use that function because,
405 // we allocate the InstanceKlass at load time, and that requires that the
406 // superclass has been loaded.
407 // However, the vtable entries are filled in at link time, and therefore
408 // the superclass' vtable may not yet have been filled in.
409 bool klassVtable::needs_new_vtable_entry(methodHandle target_method,
410 Klass* super,
411 Handle classloader,
412 Symbol* classname,
413 AccessFlags class_flags,
414 TRAPS) {
415 if (class_flags.is_interface()) {
416 // Interfaces do not use vtables, so there is no point to assigning
417 // a vtable index to any of their methods. If we refrain from doing this,
418 // we can use Method::_vtable_index to hold the itable index
419 return false;
420 }
421
422 if (target_method->is_final_method(class_flags) ||
423 // a final method never needs a new entry; final methods can be statically
424 // resolved and they have to be present in the vtable only if they override
425 // a super's method, in which case they re-use its entry
426 (target_method()->is_static()) ||
427 // static methods don't need to be in vtable
428 (target_method()->name() == vmSymbols::object_initializer_name())
429 // <init> is never called dynamically-bound
430 ) {
431 return false;
432 }
433
434 // we need a new entry if there is no superclass
435 if (super == NULL) {
436 return true;
437 }
438
439 // private methods always have a new entry in the vtable
440 // specification interpretation since classic has
441 // private methods not overriding
442 if (target_method()->is_private()) {
443 return true;
444 }
445
446 // search through the super class hierarchy to see if we need
447 // a new entry
448 ResourceMark rm;
449 Symbol* name = target_method()->name();
450 Symbol* signature = target_method()->signature();
451 Klass* k = super;
452 Method* super_method = NULL;
453 InstanceKlass *holder = NULL;
454 Method* recheck_method = NULL;
455 while (k != NULL) {
456 // lookup through the hierarchy for a method with matching name and sign.
457 super_method = InstanceKlass::cast(k)->lookup_method(name, signature);
458 if (super_method == NULL) {
459 break; // we still have to search for a matching miranda method
460 }
461 // get the class holding the matching method
462 // make sure you use that class for is_override
463 InstanceKlass* superk = super_method->method_holder();
464 // we want only instance method matches
465 // pretend private methods are not in the super vtable
466 // since we do override around them: e.g. a.m pub/b.m private/c.m pub,
467 // ignore private, c.m pub does override a.m pub
468 // For classes that were not javac'd together, we also do transitive overriding around
469 // methods that have less accessibility
470 if ((!super_method->is_static()) &&
471 (!super_method->is_private())) {
472 if (superk->is_override(super_method, classloader, classname, THREAD)) {
473 return false;
474 // else keep looking for transitive overrides
475 }
476 }
477
478 // Start with lookup result and continue to search up
479 k = superk->super(); // haven't found an override match yet; continue to look
480 }
481
482 // if the target method is public or protected it may have a matching
483 // miranda method in the super, whose entry it should re-use.
484 // Actually, to handle cases that javac would not generate, we need
485 // this check for all access permissions.
486 InstanceKlass *sk = InstanceKlass::cast(super);
487 if (sk->has_miranda_methods()) {
488 if (sk->lookup_method_in_all_interfaces(name, signature) != NULL) {
489 return false; // found a matching miranda; we do not need a new entry
490 }
491 }
492 return true; // found no match; we need a new entry
493 }
494
495 // Support for miranda methods
496
497 // get the vtable index of a miranda method with matching "name" and "signature"
498 int klassVtable::index_of_miranda(Symbol* name, Symbol* signature) {
499 // search from the bottom, might be faster
500 for (int i = (length() - 1); i >= 0; i--) {
501 Method* m = table()[i].method();
502 if (is_miranda_entry_at(i) &&
503 m->name() == name && m->signature() == signature) {
504 return i;
505 }
506 }
507 return Method::invalid_vtable_index;
508 }
509
510 // check if an entry is miranda
511 bool klassVtable::is_miranda_entry_at(int i) {
512 Method* m = method_at(i);
513 Klass* method_holder = m->method_holder();
514 InstanceKlass *mhk = InstanceKlass::cast(method_holder);
515
516 // miranda methods are interface methods in a class's vtable
517 if (mhk->is_interface()) {
518 assert(m->is_public(), "should be public");
519 assert(ik()->implements_interface(method_holder) , "this class should implement the interface");
520 assert(is_miranda(m, ik()->methods(), ik()->super()), "should be a miranda_method");
521 return true;
522 }
523 return false;
524 }
525
526 // check if a method is a miranda method, given a class's methods table and it's super
527 // the caller must make sure that the method belongs to an interface implemented by the class
528 bool klassVtable::is_miranda(Method* m, Array<Method*>* class_methods, Klass* super) {
529 if (m->is_static()) {
530 return false;
531 }
532 Symbol* name = m->name();
533 Symbol* signature = m->signature();
534 if (InstanceKlass::find_method(class_methods, name, signature) == NULL) {
535 // did not find it in the method table of the current class
536 if (super == NULL) {
537 // super doesn't exist
538 return true;
539 }
540
541 Method* mo = InstanceKlass::cast(super)->lookup_method(name, signature);
542 if (mo == NULL || mo->access_flags().is_private() ) {
543 // super class hierarchy does not implement it or protection is different
544 return true;
545 }
546 }
547
548 return false;
549 }
550
551 void klassVtable::add_new_mirandas_to_lists(
552 GrowableArray<Method*>* new_mirandas, GrowableArray<Method*>* all_mirandas,
553 Array<Method*>* current_interface_methods, Array<Method*>* class_methods,
554 Klass* super) {
555 // iterate thru the current interface's method to see if it a miranda
556 int num_methods = current_interface_methods->length();
557 for (int i = 0; i < num_methods; i++) {
558 Method* im = current_interface_methods->at(i);
559 bool is_duplicate = false;
560 int num_of_current_mirandas = new_mirandas->length();
561 // check for duplicate mirandas in different interfaces we implement
562 for (int j = 0; j < num_of_current_mirandas; j++) {
563 Method* miranda = new_mirandas->at(j);
564 if ((im->name() == miranda->name()) &&
565 (im->signature() == miranda->signature())) {
566 is_duplicate = true;
567 break;
568 }
569 }
570
571 if (!is_duplicate) { // we don't want duplicate miranda entries in the vtable
572 if (is_miranda(im, class_methods, super)) { // is it a miranda at all?
573 InstanceKlass *sk = InstanceKlass::cast(super);
574 // check if it is a duplicate of a super's miranda
575 if (sk->lookup_method_in_all_interfaces(im->name(), im->signature()) == NULL) {
576 new_mirandas->append(im);
577 }
578 if (all_mirandas != NULL) {
579 all_mirandas->append(im);
580 }
581 }
582 }
583 }
584 }
585
586 void klassVtable::get_mirandas(GrowableArray<Method*>* new_mirandas,
587 GrowableArray<Method*>* all_mirandas,
588 Klass* super, Array<Method*>* class_methods,
589 Array<Klass*>* local_interfaces) {
590 assert((new_mirandas->length() == 0) , "current mirandas must be 0");
591
592 // iterate thru the local interfaces looking for a miranda
593 int num_local_ifs = local_interfaces->length();
594 for (int i = 0; i < num_local_ifs; i++) {
595 InstanceKlass *ik = InstanceKlass::cast(local_interfaces->at(i));
596 add_new_mirandas_to_lists(new_mirandas, all_mirandas,
597 ik->methods(), class_methods, super);
598 // iterate thru each local's super interfaces
599 Array<Klass*>* super_ifs = ik->transitive_interfaces();
600 int num_super_ifs = super_ifs->length();
601 for (int j = 0; j < num_super_ifs; j++) {
602 InstanceKlass *sik = InstanceKlass::cast(super_ifs->at(j));
603 add_new_mirandas_to_lists(new_mirandas, all_mirandas,
604 sik->methods(), class_methods, super);
605 }
606 }
607 }
608
609 // fill in mirandas
610 void klassVtable::fill_in_mirandas(int* initialized) {
611 GrowableArray<Method*> mirandas(20);
612 get_mirandas(&mirandas, NULL, ik()->super(), ik()->methods(),
613 ik()->local_interfaces());
614 for (int i = 0; i < mirandas.length(); i++) {
615 put_method_at(mirandas.at(i), *initialized);
616 ++(*initialized);
617 }
618 }
619
620 void klassVtable::copy_vtable_to(vtableEntry* start) {
621 Copy::disjoint_words((HeapWord*)table(), (HeapWord*)start, _length * vtableEntry::size());
622 }
623
624 #if INCLUDE_JVMTI
625 void klassVtable::adjust_method_entries(Method** old_methods, Method** new_methods,
626 int methods_length, bool * trace_name_printed) {
627 // search the vtable for uses of either obsolete or EMCP methods
628 for (int j = 0; j < methods_length; j++) {
629 Method* old_method = old_methods[j];
630 Method* new_method = new_methods[j];
631
632 // In the vast majority of cases we could get the vtable index
633 // by using: old_method->vtable_index()
634 // However, there are rare cases, eg. sun.awt.X11.XDecoratedPeer.getX()
635 // in sun.awt.X11.XFramePeer where methods occur more than once in the
636 // vtable, so, alas, we must do an exhaustive search.
637 for (int index = 0; index < length(); index++) {
638 if (unchecked_method_at(index) == old_method) {
639 put_method_at(new_method, index);
640
641 if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
642 if (!(*trace_name_printed)) {
643 // RC_TRACE_MESG macro has an embedded ResourceMark
644 RC_TRACE_MESG(("adjust: name=%s",
645 old_method->method_holder()->external_name()));
646 *trace_name_printed = true;
647 }
648 // RC_TRACE macro has an embedded ResourceMark
649 RC_TRACE(0x00100000, ("vtable method update: %s(%s)",
650 new_method->name()->as_C_string(),
651 new_method->signature()->as_C_string()));
652 }
653 // cannot 'break' here; see for-loop comment above.
654 }
655 }
656 }
657 }
658
659 // a vtable should never contain old or obsolete methods
660 bool klassVtable::check_no_old_or_obsolete_entries() {
661 for (int i = 0; i < length(); i++) {
662 Method* m = unchecked_method_at(i);
663 if (m != NULL &&
664 (NOT_PRODUCT(!m->is_valid() ||) m->is_old() || m->is_obsolete())) {
665 return false;
666 }
667 }
668 return true;
669 }
670
671 void klassVtable::dump_vtable() {
672 tty->print_cr("vtable dump --");
673 for (int i = 0; i < length(); i++) {
674 Method* m = unchecked_method_at(i);
675 if (m != NULL) {
676 tty->print(" (%5d) ", i);
677 m->access_flags().print_on(tty);
678 tty->print(" -- ");
679 m->print_name(tty);
680 tty->cr();
681 }
682 }
683 }
684 #endif // INCLUDE_JVMTI
685
686 // CDS/RedefineClasses support - clear vtables so they can be reinitialized
687 void klassVtable::clear_vtable() {
688 for (int i = 0; i < _length; i++) table()[i].clear();
689 }
690
691 bool klassVtable::is_initialized() {
692 return _length == 0 || table()[0].method() != NULL;
693 }
694
695 //-----------------------------------------------------------------------------------------
696 // Itable code
697
698 // Initialize a itableMethodEntry
699 void itableMethodEntry::initialize(Method* m) {
700 if (m == NULL) return;
701
702 _method = m;
703 }
704
705 klassItable::klassItable(instanceKlassHandle klass) {
706 _klass = klass;
707
708 if (klass->itable_length() > 0) {
709 itableOffsetEntry* offset_entry = (itableOffsetEntry*)klass->start_of_itable();
710 if (offset_entry != NULL && offset_entry->interface_klass() != NULL) { // Check that itable is initialized
711 // First offset entry points to the first method_entry
712 intptr_t* method_entry = (intptr_t *)(((address)klass()) + offset_entry->offset());
713 intptr_t* end = klass->end_of_itable();
714
715 _table_offset = (intptr_t*)offset_entry - (intptr_t*)klass();
716 _size_offset_table = (method_entry - ((intptr_t*)offset_entry)) / itableOffsetEntry::size();
717 _size_method_table = (end - method_entry) / itableMethodEntry::size();
718 assert(_table_offset >= 0 && _size_offset_table >= 0 && _size_method_table >= 0, "wrong computation");
719 return;
720 }
721 }
722
723 // The length of the itable was either zero, or it has not yet been initialized.
724 _table_offset = 0;
725 _size_offset_table = 0;
726 _size_method_table = 0;
727 }
728
729 static int initialize_count = 0;
730
731 // Initialization
732 void klassItable::initialize_itable(bool checkconstraints, TRAPS) {
733 if (_klass->is_interface()) {
734 // This needs to go after vtable indexes are assigned but
735 // before implementors need to know the number of itable indexes.
736 assign_itable_indexes_for_interface(_klass());
737 }
738
739 // Cannot be setup doing bootstrapping, interfaces don't have
740 // itables, and klass with only ones entry have empty itables
741 if (Universe::is_bootstrapping() ||
742 _klass->is_interface() ||
743 _klass->itable_length() == itableOffsetEntry::size()) return;
744
745 // There's alway an extra itable entry so we can null-terminate it.
746 guarantee(size_offset_table() >= 1, "too small");
747 int num_interfaces = size_offset_table() - 1;
748 if (num_interfaces > 0) {
749 if (TraceItables) tty->print_cr("%3d: Initializing itables for %s", ++initialize_count,
750 _klass->name()->as_C_string());
751
752
753 // Iterate through all interfaces
754 int i;
755 for(i = 0; i < num_interfaces; i++) {
756 itableOffsetEntry* ioe = offset_entry(i);
757 HandleMark hm(THREAD);
758 KlassHandle interf_h (THREAD, ioe->interface_klass());
759 assert(interf_h() != NULL && ioe->offset() != 0, "bad offset entry in itable");
760 initialize_itable_for_interface(ioe->offset(), interf_h, checkconstraints, CHECK);
761 }
762
763 }
764 // Check that the last entry is empty
765 itableOffsetEntry* ioe = offset_entry(size_offset_table() - 1);
766 guarantee(ioe->interface_klass() == NULL && ioe->offset() == 0, "terminator entry missing");
767 }
768
769
770 inline bool interface_method_needs_itable_index(Method* m) {
771 if (m->is_static()) return false; // e.g., Stream.empty
772 if (m->is_initializer()) return false; // <init> or <clinit>
773 // Some methods might get assigned vtable indexes, but we cannot predict this.
774 //if (m->has_vtable_index()) return false; // e.g., CharSequence.toString (from initialize_vtable)
775 return true;
776 }
777
778 int klassItable::assign_itable_indexes_for_interface(Klass* klass) {
779 // an interface does not have an itable, but its methods need to be numbered
780 if (TraceItables) tty->print_cr("%3d: Initializing itable for interface %s", ++initialize_count,
781 klass->name()->as_C_string());
782 Array<Method*>* methods = InstanceKlass::cast(klass)->methods();
783 int nof_methods = methods->length();
784 int ime_num = 0;
785 for (int i = 0; i < nof_methods; i++) {
786 Method* m = methods->at(i);
787 if (interface_method_needs_itable_index(m)) {
788 assert(!m->is_final_method(), "no final interface methods");
789 // If m is already assigned a vtable index, do not disturb it.
790 if (!m->has_vtable_index()) {
791 assert(m->vtable_index() == Method::pending_itable_index, "set by initialize_vtable");
792 m->set_itable_index(ime_num);
793 // Progress to next itable entry
794 ime_num++;
795 }
796 }
797 }
798 assert(ime_num == method_count_for_interface(klass), "proper sizing");
799 return ime_num;
800 }
801
802 int klassItable::method_count_for_interface(Klass* interf) {
803 assert(interf->oop_is_instance(), "must be");
804 assert(interf->is_interface(), "must be");
805 Array<Method*>* methods = InstanceKlass::cast(interf)->methods();
806 int nof_methods = methods->length();
807 while (nof_methods > 0) {
808 Method* m = methods->at(nof_methods-1);
809 if (m->has_itable_index()) {
810 int length = m->itable_index() + 1;
811 #ifdef ASSERT
812 while (nof_methods = 0) {
813 m = methods->at(--nof_methods);
814 assert(!m->has_itable_index() || m->itable_index() < length, "");
815 }
816 #endif //ASSERT
817 return length; // return the rightmost itable index, plus one
818 }
819 nof_methods -= 1;
820 }
821 // no methods have itable indexes
822 return 0;
823 }
824
825
826 void klassItable::initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS) {
827 Array<Method*>* methods = InstanceKlass::cast(interf_h())->methods();
828 int nof_methods = methods->length();
829 HandleMark hm;
830 assert(nof_methods > 0, "at least one method must exist for interface to be in vtable");
831 Handle interface_loader (THREAD, InstanceKlass::cast(interf_h())->class_loader());
832
833 int ime_count = method_count_for_interface(interf_h());
834 for (int i = 0; i < nof_methods; i++) {
835 Method* m = methods->at(i);
836 methodHandle target;
837 if (m->has_itable_index()) {
838 LinkResolver::lookup_instance_method_in_klasses(target, _klass, m->name(), m->signature(), CHECK);
839 }
840 if (target == NULL || !target->is_public() || target->is_abstract()) {
841 // Entry do not resolve. Leave it empty
842 } else {
843 // Entry did resolve, check loader constraints before initializing
844 // if checkconstraints requested
845 if (checkconstraints) {
846 Handle method_holder_loader (THREAD, target->method_holder()->class_loader());
847 if (method_holder_loader() != interface_loader()) {
848 ResourceMark rm(THREAD);
849 Symbol* failed_type_symbol =
850 SystemDictionary::check_signature_loaders(m->signature(),
851 method_holder_loader,
852 interface_loader,
853 true, CHECK);
854 if (failed_type_symbol != NULL) {
855 const char* msg = "loader constraint violation in interface "
856 "itable initialization: when resolving method \"%s\" the class"
857 " loader (instance of %s) of the current class, %s, "
858 "and the class loader (instance of %s) for interface "
859 "%s have different Class objects for the type %s "
860 "used in the signature";
861 char* sig = target()->name_and_sig_as_C_string();
862 const char* loader1 = SystemDictionary::loader_name(method_holder_loader());
863 char* current = _klass->name()->as_C_string();
864 const char* loader2 = SystemDictionary::loader_name(interface_loader());
865 char* iface = InstanceKlass::cast(interf_h())->name()->as_C_string();
866 char* failed_type_name = failed_type_symbol->as_C_string();
867 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
868 strlen(current) + strlen(loader2) + strlen(iface) +
869 strlen(failed_type_name);
870 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
871 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2,
872 iface, failed_type_name);
873 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
874 }
875 }
876 }
877
878 // ime may have moved during GC so recalculate address
879 int ime_num = m->itable_index();
880 assert(ime_num < ime_count, "oob");
881 itableOffsetEntry::method_entry(_klass(), method_table_offset)[ime_num].initialize(target());
882 }
883 }
884 }
885
886 // Update entry for specific Method*
887 void klassItable::initialize_with_method(Method* m) {
888 itableMethodEntry* ime = method_entry(0);
889 for(int i = 0; i < _size_method_table; i++) {
890 if (ime->method() == m) {
891 ime->initialize(m);
892 }
893 ime++;
894 }
895 }
896
897 #if INCLUDE_JVMTI
898 void klassItable::adjust_method_entries(Method** old_methods, Method** new_methods,
899 int methods_length, bool * trace_name_printed) {
900 // search the itable for uses of either obsolete or EMCP methods
901 for (int j = 0; j < methods_length; j++) {
902 Method* old_method = old_methods[j];
903 Method* new_method = new_methods[j];
904 itableMethodEntry* ime = method_entry(0);
905
906 // The itable can describe more than one interface and the same
907 // method signature can be specified by more than one interface.
908 // This means we have to do an exhaustive search to find all the
909 // old_method references.
910 for (int i = 0; i < _size_method_table; i++) {
911 if (ime->method() == old_method) {
912 ime->initialize(new_method);
913
914 if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
915 if (!(*trace_name_printed)) {
916 // RC_TRACE_MESG macro has an embedded ResourceMark
917 RC_TRACE_MESG(("adjust: name=%s",
918 old_method->method_holder()->external_name()));
919 *trace_name_printed = true;
920 }
921 // RC_TRACE macro has an embedded ResourceMark
922 RC_TRACE(0x00200000, ("itable method update: %s(%s)",
923 new_method->name()->as_C_string(),
924 new_method->signature()->as_C_string()));
925 }
926 // cannot 'break' here; see for-loop comment above.
927 }
928 ime++;
929 }
930 }
931 }
932
933 // an itable should never contain old or obsolete methods
934 bool klassItable::check_no_old_or_obsolete_entries() {
935 itableMethodEntry* ime = method_entry(0);
936 for (int i = 0; i < _size_method_table; i++) {
937 Method* m = ime->method();
938 if (m != NULL &&
939 (NOT_PRODUCT(!m->is_valid() ||) m->is_old() || m->is_obsolete())) {
940 return false;
941 }
942 ime++;
943 }
944 return true;
945 }
946
947 void klassItable::dump_itable() {
948 itableMethodEntry* ime = method_entry(0);
949 tty->print_cr("itable dump --");
950 for (int i = 0; i < _size_method_table; i++) {
951 Method* m = ime->method();
952 if (m != NULL) {
953 tty->print(" (%5d) ", i);
954 m->access_flags().print_on(tty);
955 tty->print(" -- ");
956 m->print_name(tty);
957 tty->cr();
958 }
959 ime++;
960 }
961 }
962 #endif // INCLUDE_JVMTI
963
964
965 // Setup
966 class InterfaceVisiterClosure : public StackObj {
967 public:
968 virtual void doit(Klass* intf, int method_count) = 0;
969 };
970
971 // Visit all interfaces with at least one itable method
972 void visit_all_interfaces(Array<Klass*>* transitive_intf, InterfaceVisiterClosure *blk) {
973 // Handle array argument
974 for(int i = 0; i < transitive_intf->length(); i++) {
975 Klass* intf = transitive_intf->at(i);
976 assert(intf->is_interface(), "sanity check");
977
978 // Find no. of itable methods
979 int method_count = 0;
980 // method_count = klassItable::method_count_for_interface(intf);
981 Array<Method*>* methods = InstanceKlass::cast(intf)->methods();
982 if (methods->length() > 0) {
983 for (int i = methods->length(); --i >= 0; ) {
984 if (interface_method_needs_itable_index(methods->at(i))) {
985 method_count++;
986 }
987 }
988 }
989
990 // Only count interfaces with at least one method
991 if (method_count > 0) {
992 blk->doit(intf, method_count);
993 }
994 }
995 }
996
997 class CountInterfacesClosure : public InterfaceVisiterClosure {
998 private:
999 int _nof_methods;
1000 int _nof_interfaces;
1001 public:
1002 CountInterfacesClosure() { _nof_methods = 0; _nof_interfaces = 0; }
1003
1004 int nof_methods() const { return _nof_methods; }
1005 int nof_interfaces() const { return _nof_interfaces; }
1006
1007 void doit(Klass* intf, int method_count) { _nof_methods += method_count; _nof_interfaces++; }
1008 };
1009
1010 class SetupItableClosure : public InterfaceVisiterClosure {
1011 private:
1012 itableOffsetEntry* _offset_entry;
1013 itableMethodEntry* _method_entry;
1014 address _klass_begin;
1015 public:
1016 SetupItableClosure(address klass_begin, itableOffsetEntry* offset_entry, itableMethodEntry* method_entry) {
1017 _klass_begin = klass_begin;
1018 _offset_entry = offset_entry;
1019 _method_entry = method_entry;
1020 }
1021
1022 itableMethodEntry* method_entry() const { return _method_entry; }
1023
1024 void doit(Klass* intf, int method_count) {
1025 int offset = ((address)_method_entry) - _klass_begin;
1026 _offset_entry->initialize(intf, offset);
1027 _offset_entry++;
1028 _method_entry += method_count;
1029 }
1030 };
1031
1032 int klassItable::compute_itable_size(Array<Klass*>* transitive_interfaces) {
1033 // Count no of interfaces and total number of interface methods
1034 CountInterfacesClosure cic;
1035 visit_all_interfaces(transitive_interfaces, &cic);
1036
1037 // There's alway an extra itable entry so we can null-terminate it.
1038 int itable_size = calc_itable_size(cic.nof_interfaces() + 1, cic.nof_methods());
1039
1040 // Statistics
1041 update_stats(itable_size * HeapWordSize);
1042
1043 return itable_size;
1044 }
1045
1046
1047 // Fill out offset table and interface klasses into the itable space
1048 void klassItable::setup_itable_offset_table(instanceKlassHandle klass) {
1049 if (klass->itable_length() == 0) return;
1050 assert(!klass->is_interface(), "Should have zero length itable");
1051
1052 // Count no of interfaces and total number of interface methods
1053 CountInterfacesClosure cic;
1054 visit_all_interfaces(klass->transitive_interfaces(), &cic);
1055 int nof_methods = cic.nof_methods();
1056 int nof_interfaces = cic.nof_interfaces();
1057
1058 // Add one extra entry so we can null-terminate the table
1059 nof_interfaces++;
1060
1061 assert(compute_itable_size(klass->transitive_interfaces()) ==
1062 calc_itable_size(nof_interfaces, nof_methods),
1063 "mismatch calculation of itable size");
1064
1065 // Fill-out offset table
1066 itableOffsetEntry* ioe = (itableOffsetEntry*)klass->start_of_itable();
1067 itableMethodEntry* ime = (itableMethodEntry*)(ioe + nof_interfaces);
1068 intptr_t* end = klass->end_of_itable();
1069 assert((oop*)(ime + nof_methods) <= (oop*)klass->start_of_nonstatic_oop_maps(), "wrong offset calculation (1)");
1070 assert((oop*)(end) == (oop*)(ime + nof_methods), "wrong offset calculation (2)");
1071
1072 // Visit all interfaces and initialize itable offset table
1073 SetupItableClosure sic((address)klass(), ioe, ime);
1074 visit_all_interfaces(klass->transitive_interfaces(), &sic);
1075
1076 #ifdef ASSERT
1077 ime = sic.method_entry();
1078 oop* v = (oop*) klass->end_of_itable();
1079 assert( (oop*)(ime) == v, "wrong offset calculation (2)");
1080 #endif
1081 }
1082
1083
1084 // inverse to itable_index
1085 Method* klassItable::method_for_itable_index(Klass* intf, int itable_index) {
1086 assert(InstanceKlass::cast(intf)->is_interface(), "sanity check");
1087 assert(intf->verify_itable_index(itable_index), "");
1088 Array<Method*>* methods = InstanceKlass::cast(intf)->methods();
1089
1090 if (itable_index < 0 || itable_index >= method_count_for_interface(intf))
1091 return NULL; // help caller defend against bad indexes
1092
1093 int index = itable_index;
1094 Method* m = methods->at(index);
1095 int index2 = -1;
1096 while (!m->has_itable_index() ||
1097 (index2 = m->itable_index()) != itable_index) {
1098 assert(index2 < itable_index, "monotonic");
1099 if (++index == methods->length())
1100 return NULL;
1101 m = methods->at(index);
1102 }
1103 assert(m->itable_index() == itable_index, "correct inverse");
1104
1105 return m;
1106 }
1107
1108 void klassVtable::verify(outputStream* st, bool forced) {
1109 // make sure table is initialized
1110 if (!Universe::is_fully_initialized()) return;
1111 #ifndef PRODUCT
1112 // avoid redundant verifies
1113 if (!forced && _verify_count == Universe::verify_count()) return;
1114 _verify_count = Universe::verify_count();
1115 #endif
1116 oop* end_of_obj = (oop*)_klass() + _klass()->size();
1117 oop* end_of_vtable = (oop *)&table()[_length];
1118 if (end_of_vtable > end_of_obj) {
1119 fatal(err_msg("klass %s: klass object too short (vtable extends beyond "
1120 "end)", _klass->internal_name()));
1121 }
1122
1123 for (int i = 0; i < _length; i++) table()[i].verify(this, st);
1124 // verify consistency with superKlass vtable
1125 Klass* super = _klass->super();
1126 if (super != NULL) {
1127 InstanceKlass* sk = InstanceKlass::cast(super);
1128 klassVtable* vt = sk->vtable();
1129 for (int i = 0; i < vt->length(); i++) {
1130 verify_against(st, vt, i);
1131 }
1132 }
1133 }
1134
1135 void klassVtable::verify_against(outputStream* st, klassVtable* vt, int index) {
1136 vtableEntry* vte = &vt->table()[index];
1137 if (vte->method()->name() != table()[index].method()->name() ||
1138 vte->method()->signature() != table()[index].method()->signature()) {
1139 fatal("mismatched name/signature of vtable entries");
1140 }
1141 }
1142
1143 #ifndef PRODUCT
1144 void klassVtable::print() {
1145 ResourceMark rm;
1146 tty->print("klassVtable for klass %s (length %d):\n", _klass->internal_name(), length());
1147 for (int i = 0; i < length(); i++) {
1148 table()[i].print();
1149 tty->cr();
1150 }
1151 }
1152 #endif
1153
1154 void vtableEntry::verify(klassVtable* vt, outputStream* st) {
1155 NOT_PRODUCT(FlagSetting fs(IgnoreLockingAssertions, true));
1156 assert(method() != NULL, "must have set method");
1157 method()->verify();
1158 // we sub_type, because it could be a miranda method
1159 if (!vt->klass()->is_subtype_of(method()->method_holder())) {
1160 #ifndef PRODUCT
1161 print();
1162 #endif
1163 fatal(err_msg("vtableEntry " PTR_FORMAT ": method is from subclass", this));
1164 }
1165 }
1166
1167 #ifndef PRODUCT
1168
1169 void vtableEntry::print() {
1170 ResourceMark rm;
1171 tty->print("vtableEntry %s: ", method()->name()->as_C_string());
1172 if (Verbose) {
1173 tty->print("m %#lx ", (address)method());
1174 }
1175 }
1176
1177 class VtableStats : AllStatic {
1178 public:
1179 static int no_klasses; // # classes with vtables
1180 static int no_array_klasses; // # array classes
1181 static int no_instance_klasses; // # instanceKlasses
1182 static int sum_of_vtable_len; // total # of vtable entries
1183 static int sum_of_array_vtable_len; // total # of vtable entries in array klasses only
1184 static int fixed; // total fixed overhead in bytes
1185 static int filler; // overhead caused by filler bytes
1186 static int entries; // total bytes consumed by vtable entries
1187 static int array_entries; // total bytes consumed by array vtable entries
1188
1189 static void do_class(Klass* k) {
1190 Klass* kl = k;
1191 klassVtable* vt = kl->vtable();
1192 if (vt == NULL) return;
1193 no_klasses++;
1194 if (kl->oop_is_instance()) {
1195 no_instance_klasses++;
1196 kl->array_klasses_do(do_class);
1197 }
1198 if (kl->oop_is_array()) {
1199 no_array_klasses++;
1200 sum_of_array_vtable_len += vt->length();
1201 }
1202 sum_of_vtable_len += vt->length();
1203 }
1204
1205 static void compute() {
1206 SystemDictionary::classes_do(do_class);
1207 fixed = no_klasses * oopSize; // vtable length
1208 // filler size is a conservative approximation
1209 filler = oopSize * (no_klasses - no_instance_klasses) * (sizeof(InstanceKlass) - sizeof(ArrayKlass) - 1);
1210 entries = sizeof(vtableEntry) * sum_of_vtable_len;
1211 array_entries = sizeof(vtableEntry) * sum_of_array_vtable_len;
1212 }
1213 };
1214
1215 int VtableStats::no_klasses = 0;
1216 int VtableStats::no_array_klasses = 0;
1217 int VtableStats::no_instance_klasses = 0;
1218 int VtableStats::sum_of_vtable_len = 0;
1219 int VtableStats::sum_of_array_vtable_len = 0;
1220 int VtableStats::fixed = 0;
1221 int VtableStats::filler = 0;
1222 int VtableStats::entries = 0;
1223 int VtableStats::array_entries = 0;
1224
1225 void klassVtable::print_statistics() {
1226 ResourceMark rm;
1227 HandleMark hm;
1228 VtableStats::compute();
1229 tty->print_cr("vtable statistics:");
1230 tty->print_cr("%6d classes (%d instance, %d array)", VtableStats::no_klasses, VtableStats::no_instance_klasses, VtableStats::no_array_klasses);
1231 int total = VtableStats::fixed + VtableStats::filler + VtableStats::entries;
1232 tty->print_cr("%6d bytes fixed overhead (refs + vtable object header)", VtableStats::fixed);
1233 tty->print_cr("%6d bytes filler overhead", VtableStats::filler);
1234 tty->print_cr("%6d bytes for vtable entries (%d for arrays)", VtableStats::entries, VtableStats::array_entries);
1235 tty->print_cr("%6d bytes total", total);
1236 }
1237
1238 int klassItable::_total_classes; // Total no. of classes with itables
1239 long klassItable::_total_size; // Total no. of bytes used for itables
1240
1241 void klassItable::print_statistics() {
1242 tty->print_cr("itable statistics:");
1243 tty->print_cr("%6d classes with itables", _total_classes);
1244 tty->print_cr("%6d K uses for itables (average by class: %d bytes)", _total_size / K, _total_size / _total_classes);
1245 }
1246
1247 #endif // PRODUCT