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