Tue, 09 Oct 2012 07:41:27 +0200
Merge
1 /*
2 * Copyright (c) 1997, 2012, 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 */
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"
42 inline InstanceKlass* klassVtable::ik() const {
43 Klass* k = _klass();
44 assert(k->oop_is_instance(), "not an InstanceKlass");
45 return (InstanceKlass*)k;
46 }
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(int &vtable_length,
58 int &num_miranda_methods,
59 Klass* super,
60 Array<Method*>* methods,
61 AccessFlags class_flags,
62 Handle classloader,
63 Symbol* classname,
64 Array<Klass*>* local_interfaces,
65 TRAPS
66 ) {
68 No_Safepoint_Verifier nsv;
70 // set up default result values
71 vtable_length = 0;
72 num_miranda_methods = 0;
74 // start off with super's vtable length
75 InstanceKlass* sk = (InstanceKlass*)super;
76 vtable_length = super == NULL ? 0 : sk->vtable_length();
78 // go thru each method in the methods table to see if it needs a new entry
79 int len = methods->length();
80 for (int i = 0; i < len; i++) {
81 assert(methods->at(i)->is_method(), "must be a Method*");
82 methodHandle mh(THREAD, methods->at(i));
84 if (needs_new_vtable_entry(mh, super, classloader, classname, class_flags, THREAD)) {
85 vtable_length += vtableEntry::size(); // we need a new entry
86 }
87 }
89 // compute the number of mirandas methods that must be added to the end
90 num_miranda_methods = get_num_mirandas(super, methods, local_interfaces);
91 vtable_length += (num_miranda_methods * vtableEntry::size());
93 if (Universe::is_bootstrapping() && vtable_length == 0) {
94 // array classes don't have their superclass set correctly during
95 // bootstrapping
96 vtable_length = Universe::base_vtable_size();
97 }
99 if (super == NULL && !Universe::is_bootstrapping() &&
100 vtable_length != Universe::base_vtable_size()) {
101 // Someone is attempting to redefine java.lang.Object incorrectly. The
102 // only way this should happen is from
103 // SystemDictionary::resolve_from_stream(), which will detect this later
104 // and throw a security exception. So don't assert here to let
105 // the exception occur.
106 vtable_length = Universe::base_vtable_size();
107 }
108 assert(super != NULL || vtable_length == Universe::base_vtable_size(),
109 "bad vtable size for class Object");
110 assert(vtable_length % vtableEntry::size() == 0, "bad vtable length");
111 assert(vtable_length >= Universe::base_vtable_size(), "vtable too small");
112 }
114 int klassVtable::index_of(Method* m, int len) const {
115 assert(m->vtable_index() >= 0, "do not ask this of non-vtable methods");
116 return m->vtable_index();
117 }
119 int klassVtable::initialize_from_super(KlassHandle super) {
120 if (super.is_null()) {
121 return 0;
122 } else {
123 // copy methods from superKlass
124 // can't inherit from array class, so must be InstanceKlass
125 assert(super->oop_is_instance(), "must be instance klass");
126 InstanceKlass* sk = (InstanceKlass*)super();
127 klassVtable* superVtable = sk->vtable();
128 assert(superVtable->length() <= _length, "vtable too short");
129 #ifdef ASSERT
130 superVtable->verify(tty, true);
131 #endif
132 superVtable->copy_vtable_to(table());
133 #ifndef PRODUCT
134 if (PrintVtables && Verbose) {
135 ResourceMark rm;
136 tty->print_cr("copy vtable from %s to %s size %d", sk->internal_name(), klass()->internal_name(), _length);
137 }
138 #endif
139 return superVtable->length();
140 }
141 }
143 // Revised lookup semantics introduced 1.3 (Kestral beta)
144 void klassVtable::initialize_vtable(bool checkconstraints, TRAPS) {
146 // Note: Arrays can have intermediate array supers. Use java_super to skip them.
147 KlassHandle super (THREAD, klass()->java_super());
148 int nofNewEntries = 0;
151 if (PrintVtables && !klass()->oop_is_array()) {
152 ResourceMark rm(THREAD);
153 tty->print_cr("Initializing: %s", _klass->name()->as_C_string());
154 }
156 #ifdef ASSERT
157 oop* end_of_obj = (oop*)_klass() + _klass()->size();
158 oop* end_of_vtable = (oop*)&table()[_length];
159 assert(end_of_vtable <= end_of_obj, "vtable extends beyond end");
160 #endif
162 if (Universe::is_bootstrapping()) {
163 // just clear everything
164 for (int i = 0; i < _length; i++) table()[i].clear();
165 return;
166 }
168 int super_vtable_len = initialize_from_super(super);
169 if (klass()->oop_is_array()) {
170 assert(super_vtable_len == _length, "arrays shouldn't introduce new methods");
171 } else {
172 assert(_klass->oop_is_instance(), "must be InstanceKlass");
174 Array<Method*>* methods = ik()->methods();
175 int len = methods->length();
176 int initialized = super_vtable_len;
178 // update_inherited_vtable can stop for gc - ensure using handles
179 for (int i = 0; i < len; i++) {
180 HandleMark hm(THREAD);
181 assert(methods->at(i)->is_method(), "must be a Method*");
182 methodHandle mh(THREAD, methods->at(i));
184 bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, checkconstraints, CHECK);
186 if (needs_new_entry) {
187 put_method_at(mh(), initialized);
188 mh()->set_vtable_index(initialized); // set primary vtable index
189 initialized++;
190 }
191 }
193 // add miranda methods; it will also update the value of initialized
194 fill_in_mirandas(initialized);
196 // In class hierarchies where the accessibility is not increasing (i.e., going from private ->
197 // package_private -> publicprotected), the vtable might actually be smaller than our initial
198 // calculation.
199 assert(initialized <= _length, "vtable initialization failed");
200 for(;initialized < _length; initialized++) {
201 put_method_at(NULL, initialized);
202 }
203 NOT_PRODUCT(verify(tty, true));
204 }
205 }
207 // Called for cases where a method does not override its superclass' vtable entry
208 // For bytecodes not produced by javac together it is possible that a method does not override
209 // the superclass's method, but might indirectly override a super-super class's vtable entry
210 // If none found, return a null superk, else return the superk of the method this does override
211 InstanceKlass* klassVtable::find_transitive_override(InstanceKlass* initialsuper, methodHandle target_method,
212 int vtable_index, Handle target_loader, Symbol* target_classname, Thread * THREAD) {
213 InstanceKlass* superk = initialsuper;
214 while (superk != NULL && superk->super() != NULL) {
215 InstanceKlass* supersuperklass = InstanceKlass::cast(superk->super());
216 klassVtable* ssVtable = supersuperklass->vtable();
217 if (vtable_index < ssVtable->length()) {
218 Method* super_method = ssVtable->method_at(vtable_index);
219 #ifndef PRODUCT
220 Symbol* name= target_method()->name();
221 Symbol* signature = target_method()->signature();
222 assert(super_method->name() == name && super_method->signature() == signature, "vtable entry name/sig mismatch");
223 #endif
224 if (supersuperklass->is_override(super_method, target_loader, target_classname, THREAD)) {
225 #ifndef PRODUCT
226 if (PrintVtables && Verbose) {
227 ResourceMark rm(THREAD);
228 tty->print("transitive overriding superclass %s with %s::%s index %d, original flags: ",
229 supersuperklass->internal_name(),
230 _klass->internal_name(), (target_method() != NULL) ?
231 target_method()->name()->as_C_string() : "<NULL>", vtable_index);
232 super_method->access_flags().print_on(tty);
233 tty->print("overriders flags: ");
234 target_method->access_flags().print_on(tty);
235 tty->cr();
236 }
237 #endif /*PRODUCT*/
238 break; // return found superk
239 }
240 } else {
241 // super class has no vtable entry here, stop transitive search
242 superk = (InstanceKlass*)NULL;
243 break;
244 }
245 // if no override found yet, continue to search up
246 superk = InstanceKlass::cast(superk->super());
247 }
249 return superk;
250 }
253 // Update child's copy of super vtable for overrides
254 // OR return true if a new vtable entry is required
255 // Only called for InstanceKlass's, i.e. not for arrays
256 // If that changed, could not use _klass as handle for klass
257 bool klassVtable::update_inherited_vtable(InstanceKlass* klass, methodHandle target_method, int super_vtable_len,
258 bool checkconstraints, TRAPS) {
259 ResourceMark rm;
260 bool allocate_new = true;
261 assert(klass->oop_is_instance(), "must be InstanceKlass");
263 // Initialize the method's vtable index to "nonvirtual".
264 // If we allocate a vtable entry, we will update it to a non-negative number.
265 target_method()->set_vtable_index(Method::nonvirtual_vtable_index);
267 // Static and <init> methods are never in
268 if (target_method()->is_static() || target_method()->name() == vmSymbols::object_initializer_name()) {
269 return false;
270 }
272 if (klass->is_final() || target_method()->is_final()) {
273 // a final method never needs a new entry; final methods can be statically
274 // resolved and they have to be present in the vtable only if they override
275 // a super's method, in which case they re-use its entry
276 allocate_new = false;
277 }
279 // we need a new entry if there is no superclass
280 if (klass->super() == NULL) {
281 return allocate_new;
282 }
284 // private methods always have a new entry in the vtable
285 // specification interpretation since classic has
286 // private methods not overriding
287 if (target_method()->is_private()) {
288 return allocate_new;
289 }
291 // search through the vtable and update overridden entries
292 // Since check_signature_loaders acquires SystemDictionary_lock
293 // which can block for gc, once we are in this loop, use handles
294 // For classfiles built with >= jdk7, we now look for transitive overrides
296 Symbol* name = target_method()->name();
297 Symbol* signature = target_method()->signature();
298 Handle target_loader(THREAD, _klass()->class_loader());
299 Symbol* target_classname = _klass->name();
300 for(int i = 0; i < super_vtable_len; i++) {
301 Method* super_method = method_at(i);
302 // Check if method name matches
303 if (super_method->name() == name && super_method->signature() == signature) {
305 // get super_klass for method_holder for the found method
306 InstanceKlass* super_klass = InstanceKlass::cast(super_method->method_holder());
308 if ((super_klass->is_override(super_method, target_loader, target_classname, THREAD)) ||
309 ((klass->major_version() >= VTABLE_TRANSITIVE_OVERRIDE_VERSION)
310 && ((super_klass = find_transitive_override(super_klass, target_method, i, target_loader,
311 target_classname, THREAD)) != (InstanceKlass*)NULL))) {
312 // overriding, so no new entry
313 allocate_new = false;
315 if (checkconstraints) {
316 // Override vtable entry if passes loader constraint check
317 // if loader constraint checking requested
318 // No need to visit his super, since he and his super
319 // have already made any needed loader constraints.
320 // Since loader constraints are transitive, it is enough
321 // to link to the first super, and we get all the others.
322 Handle super_loader(THREAD, super_klass->class_loader());
324 if (target_loader() != super_loader()) {
325 ResourceMark rm(THREAD);
326 char* failed_type_name =
327 SystemDictionary::check_signature_loaders(signature, target_loader,
328 super_loader, true,
329 CHECK_(false));
330 if (failed_type_name != NULL) {
331 const char* msg = "loader constraint violation: when resolving "
332 "overridden method \"%s\" the class loader (instance"
333 " of %s) of the current class, %s, and its superclass loader "
334 "(instance of %s), have different Class objects for the type "
335 "%s used in the signature";
336 char* sig = target_method()->name_and_sig_as_C_string();
337 const char* loader1 = SystemDictionary::loader_name(target_loader());
338 char* current = _klass->name()->as_C_string();
339 const char* loader2 = SystemDictionary::loader_name(super_loader());
340 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
341 strlen(current) + strlen(loader2) + strlen(failed_type_name);
342 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
343 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2,
344 failed_type_name);
345 THROW_MSG_(vmSymbols::java_lang_LinkageError(), buf, false);
346 }
347 }
348 }
350 put_method_at(target_method(), i);
351 target_method()->set_vtable_index(i);
352 #ifndef PRODUCT
353 if (PrintVtables && Verbose) {
354 tty->print("overriding with %s::%s index %d, original flags: ",
355 _klass->internal_name(), (target_method() != NULL) ?
356 target_method()->name()->as_C_string() : "<NULL>", i);
357 super_method->access_flags().print_on(tty);
358 tty->print("overriders flags: ");
359 target_method->access_flags().print_on(tty);
360 tty->cr();
361 }
362 #endif /*PRODUCT*/
363 } else {
364 // allocate_new = true; default. We might override one entry,
365 // but not override another. Once we override one, not need new
366 #ifndef PRODUCT
367 if (PrintVtables && Verbose) {
368 tty->print("NOT overriding with %s::%s index %d, original flags: ",
369 _klass->internal_name(), (target_method() != NULL) ?
370 target_method()->name()->as_C_string() : "<NULL>", i);
371 super_method->access_flags().print_on(tty);
372 tty->print("overriders flags: ");
373 target_method->access_flags().print_on(tty);
374 tty->cr();
375 }
376 #endif /*PRODUCT*/
377 }
378 }
379 }
380 return allocate_new;
381 }
383 void klassVtable::put_method_at(Method* m, int index) {
384 #ifndef PRODUCT
385 if (PrintVtables && Verbose) {
386 ResourceMark rm;
387 tty->print_cr("adding %s::%s at index %d", _klass->internal_name(),
388 (m != NULL) ? m->name()->as_C_string() : "<NULL>", index);
389 }
390 #endif
391 table()[index].set(m);
392 }
394 // Find out if a method "m" with superclass "super", loader "classloader" and
395 // name "classname" needs a new vtable entry. Let P be a class package defined
396 // by "classloader" and "classname".
397 // NOTE: The logic used here is very similar to the one used for computing
398 // the vtables indices for a method. We cannot directly use that function because,
399 // we allocate the InstanceKlass at load time, and that requires that the
400 // superclass has been loaded.
401 // However, the vtable entries are filled in at link time, and therefore
402 // the superclass' vtable may not yet have been filled in.
403 bool klassVtable::needs_new_vtable_entry(methodHandle target_method,
404 Klass* super,
405 Handle classloader,
406 Symbol* classname,
407 AccessFlags class_flags,
408 TRAPS) {
409 if ((class_flags.is_final() || target_method()->is_final()) ||
410 // a final method never needs a new entry; final methods can be statically
411 // resolved and they have to be present in the vtable only if they override
412 // a super's method, in which case they re-use its entry
413 (target_method()->is_static()) ||
414 // static methods don't need to be in vtable
415 (target_method()->name() == vmSymbols::object_initializer_name())
416 // <init> is never called dynamically-bound
417 ) {
418 return false;
419 }
421 // we need a new entry if there is no superclass
422 if (super == NULL) {
423 return true;
424 }
426 // private methods always have a new entry in the vtable
427 // specification interpretation since classic has
428 // private methods not overriding
429 if (target_method()->is_private()) {
430 return true;
431 }
433 // search through the super class hierarchy to see if we need
434 // a new entry
435 ResourceMark rm;
436 Symbol* name = target_method()->name();
437 Symbol* signature = target_method()->signature();
438 Klass* k = super;
439 Method* super_method = NULL;
440 InstanceKlass *holder = NULL;
441 Method* recheck_method = NULL;
442 while (k != NULL) {
443 // lookup through the hierarchy for a method with matching name and sign.
444 super_method = InstanceKlass::cast(k)->lookup_method(name, signature);
445 if (super_method == NULL) {
446 break; // we still have to search for a matching miranda method
447 }
448 // get the class holding the matching method
449 // make sure you use that class for is_override
450 InstanceKlass* superk = InstanceKlass::cast(super_method->method_holder());
451 // we want only instance method matches
452 // pretend private methods are not in the super vtable
453 // since we do override around them: e.g. a.m pub/b.m private/c.m pub,
454 // ignore private, c.m pub does override a.m pub
455 // For classes that were not javac'd together, we also do transitive overriding around
456 // methods that have less accessibility
457 if ((!super_method->is_static()) &&
458 (!super_method->is_private())) {
459 if (superk->is_override(super_method, classloader, classname, THREAD)) {
460 return false;
461 // else keep looking for transitive overrides
462 }
463 }
465 // Start with lookup result and continue to search up
466 k = superk->super(); // haven't found an override match yet; continue to look
467 }
469 // if the target method is public or protected it may have a matching
470 // miranda method in the super, whose entry it should re-use.
471 // Actually, to handle cases that javac would not generate, we need
472 // this check for all access permissions.
473 InstanceKlass *sk = InstanceKlass::cast(super);
474 if (sk->has_miranda_methods()) {
475 if (sk->lookup_method_in_all_interfaces(name, signature) != NULL) {
476 return false; // found a matching miranda; we do not need a new entry
477 }
478 }
479 return true; // found no match; we need a new entry
480 }
482 // Support for miranda methods
484 // get the vtable index of a miranda method with matching "name" and "signature"
485 int klassVtable::index_of_miranda(Symbol* name, Symbol* signature) {
486 // search from the bottom, might be faster
487 for (int i = (length() - 1); i >= 0; i--) {
488 Method* m = table()[i].method();
489 if (is_miranda_entry_at(i) &&
490 m->name() == name && m->signature() == signature) {
491 return i;
492 }
493 }
494 return Method::invalid_vtable_index;
495 }
497 // check if an entry is miranda
498 bool klassVtable::is_miranda_entry_at(int i) {
499 Method* m = method_at(i);
500 Klass* method_holder = m->method_holder();
501 InstanceKlass *mhk = InstanceKlass::cast(method_holder);
503 // miranda methods are interface methods in a class's vtable
504 if (mhk->is_interface()) {
505 assert(m->is_public() && m->is_abstract(), "should be public and abstract");
506 assert(ik()->implements_interface(method_holder) , "this class should implement the interface");
507 assert(is_miranda(m, ik()->methods(), ik()->super()), "should be a miranda_method");
508 return true;
509 }
510 return false;
511 }
513 // check if a method is a miranda method, given a class's methods table and it's super
514 // the caller must make sure that the method belongs to an interface implemented by the class
515 bool klassVtable::is_miranda(Method* m, Array<Method*>* class_methods, Klass* super) {
516 Symbol* name = m->name();
517 Symbol* signature = m->signature();
518 if (InstanceKlass::find_method(class_methods, name, signature) == NULL) {
519 // did not find it in the method table of the current class
520 if (super == NULL) {
521 // super doesn't exist
522 return true;
523 }
525 Method* mo = InstanceKlass::cast(super)->lookup_method(name, signature);
526 if (mo == NULL || mo->access_flags().is_private() ) {
527 // super class hierarchy does not implement it or protection is different
528 return true;
529 }
530 }
532 return false;
533 }
535 void klassVtable::add_new_mirandas_to_list(GrowableArray<Method*>* list_of_current_mirandas,
536 Array<Method*>* current_interface_methods,
537 Array<Method*>* class_methods,
538 Klass* super) {
539 // iterate thru the current interface's method to see if it a miranda
540 int num_methods = current_interface_methods->length();
541 for (int i = 0; i < num_methods; i++) {
542 Method* im = current_interface_methods->at(i);
543 bool is_duplicate = false;
544 int num_of_current_mirandas = list_of_current_mirandas->length();
545 // check for duplicate mirandas in different interfaces we implement
546 for (int j = 0; j < num_of_current_mirandas; j++) {
547 Method* miranda = list_of_current_mirandas->at(j);
548 if ((im->name() == miranda->name()) &&
549 (im->signature() == miranda->signature())) {
550 is_duplicate = true;
551 break;
552 }
553 }
555 if (!is_duplicate) { // we don't want duplicate miranda entries in the vtable
556 if (is_miranda(im, class_methods, super)) { // is it a miranda at all?
557 InstanceKlass *sk = InstanceKlass::cast(super);
558 // check if it is a duplicate of a super's miranda
559 if (sk->lookup_method_in_all_interfaces(im->name(), im->signature()) == NULL) {
560 list_of_current_mirandas->append(im);
561 }
562 }
563 }
564 }
565 }
567 void klassVtable::get_mirandas(GrowableArray<Method*>* mirandas,
568 Klass* super, Array<Method*>* class_methods,
569 Array<Klass*>* local_interfaces) {
570 assert((mirandas->length() == 0) , "current mirandas must be 0");
572 // iterate thru the local interfaces looking for a miranda
573 int num_local_ifs = local_interfaces->length();
574 for (int i = 0; i < num_local_ifs; i++) {
575 InstanceKlass *ik = InstanceKlass::cast(local_interfaces->at(i));
576 add_new_mirandas_to_list(mirandas, ik->methods(), class_methods, super);
577 // iterate thru each local's super interfaces
578 Array<Klass*>* super_ifs = ik->transitive_interfaces();
579 int num_super_ifs = super_ifs->length();
580 for (int j = 0; j < num_super_ifs; j++) {
581 InstanceKlass *sik = InstanceKlass::cast(super_ifs->at(j));
582 add_new_mirandas_to_list(mirandas, sik->methods(), class_methods, super);
583 }
584 }
585 }
587 // get number of mirandas
588 int klassVtable::get_num_mirandas(Klass* super, Array<Method*>* class_methods, Array<Klass*>* local_interfaces) {
589 ResourceMark rm;
590 GrowableArray<Method*>* mirandas = new GrowableArray<Method*>(20);
591 get_mirandas(mirandas, super, class_methods, local_interfaces);
592 return mirandas->length();
593 }
595 // fill in mirandas
596 void klassVtable::fill_in_mirandas(int& initialized) {
597 ResourceMark rm;
598 GrowableArray<Method*>* mirandas = new GrowableArray<Method*>(20);
599 InstanceKlass *this_ik = ik();
600 get_mirandas(mirandas, this_ik->super(), this_ik->methods(), this_ik->local_interfaces());
601 int num_mirandas = mirandas->length();
602 for (int i = 0; i < num_mirandas; i++) {
603 put_method_at(mirandas->at(i), initialized);
604 initialized++;
605 }
606 }
608 void klassVtable::copy_vtable_to(vtableEntry* start) {
609 Copy::disjoint_words((HeapWord*)table(), (HeapWord*)start, _length * vtableEntry::size());
610 }
612 void klassVtable::adjust_method_entries(Method** old_methods, Method** new_methods,
613 int methods_length, bool * trace_name_printed) {
614 // search the vtable for uses of either obsolete or EMCP methods
615 for (int j = 0; j < methods_length; j++) {
616 Method* old_method = old_methods[j];
617 Method* new_method = new_methods[j];
619 // In the vast majority of cases we could get the vtable index
620 // by using: old_method->vtable_index()
621 // However, there are rare cases, eg. sun.awt.X11.XDecoratedPeer.getX()
622 // in sun.awt.X11.XFramePeer where methods occur more than once in the
623 // vtable, so, alas, we must do an exhaustive search.
624 for (int index = 0; index < length(); index++) {
625 if (unchecked_method_at(index) == old_method) {
626 put_method_at(new_method, index);
628 if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
629 if (!(*trace_name_printed)) {
630 // RC_TRACE_MESG macro has an embedded ResourceMark
631 RC_TRACE_MESG(("adjust: name=%s",
632 Klass::cast(old_method->method_holder())->external_name()));
633 *trace_name_printed = true;
634 }
635 // RC_TRACE macro has an embedded ResourceMark
636 RC_TRACE(0x00100000, ("vtable method update: %s(%s)",
637 new_method->name()->as_C_string(),
638 new_method->signature()->as_C_string()));
639 }
640 }
641 }
642 }
643 }
645 // CDS/RedefineClasses support - clear vtables so they can be reinitialized
646 void klassVtable::clear_vtable() {
647 for (int i = 0; i < _length; i++) table()[i].clear();
648 }
650 bool klassVtable::is_initialized() {
651 return _length == 0 || table()[0].method() != NULL;
652 }
654 //-----------------------------------------------------------------------------------------
655 // Itable code
657 // Initialize a itableMethodEntry
658 void itableMethodEntry::initialize(Method* m) {
659 if (m == NULL) return;
661 _method = m;
662 }
664 klassItable::klassItable(instanceKlassHandle klass) {
665 _klass = klass;
667 if (klass->itable_length() > 0) {
668 itableOffsetEntry* offset_entry = (itableOffsetEntry*)klass->start_of_itable();
669 if (offset_entry != NULL && offset_entry->interface_klass() != NULL) { // Check that itable is initialized
670 // First offset entry points to the first method_entry
671 intptr_t* method_entry = (intptr_t *)(((address)klass()) + offset_entry->offset());
672 intptr_t* end = klass->end_of_itable();
674 _table_offset = (intptr_t*)offset_entry - (intptr_t*)klass();
675 _size_offset_table = (method_entry - ((intptr_t*)offset_entry)) / itableOffsetEntry::size();
676 _size_method_table = (end - method_entry) / itableMethodEntry::size();
677 assert(_table_offset >= 0 && _size_offset_table >= 0 && _size_method_table >= 0, "wrong computation");
678 return;
679 }
680 }
682 // The length of the itable was either zero, or it has not yet been initialized.
683 _table_offset = 0;
684 _size_offset_table = 0;
685 _size_method_table = 0;
686 }
688 static int initialize_count = 0;
690 // Initialization
691 void klassItable::initialize_itable(bool checkconstraints, TRAPS) {
692 // Cannot be setup doing bootstrapping, interfaces don't have
693 // itables, and klass with only ones entry have empty itables
694 if (Universe::is_bootstrapping() ||
695 _klass->is_interface() ||
696 _klass->itable_length() == itableOffsetEntry::size()) return;
698 // There's alway an extra itable entry so we can null-terminate it.
699 guarantee(size_offset_table() >= 1, "too small");
700 int num_interfaces = size_offset_table() - 1;
701 if (num_interfaces > 0) {
702 if (TraceItables) tty->print_cr("%3d: Initializing itables for %s", ++initialize_count,
703 _klass->name()->as_C_string());
706 // Iterate through all interfaces
707 int i;
708 for(i = 0; i < num_interfaces; i++) {
709 itableOffsetEntry* ioe = offset_entry(i);
710 HandleMark hm(THREAD);
711 KlassHandle interf_h (THREAD, ioe->interface_klass());
712 assert(interf_h() != NULL && ioe->offset() != 0, "bad offset entry in itable");
713 initialize_itable_for_interface(ioe->offset(), interf_h, checkconstraints, CHECK);
714 }
716 }
717 // Check that the last entry is empty
718 itableOffsetEntry* ioe = offset_entry(size_offset_table() - 1);
719 guarantee(ioe->interface_klass() == NULL && ioe->offset() == 0, "terminator entry missing");
720 }
723 void klassItable::initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS) {
724 Array<Method*>* methods = InstanceKlass::cast(interf_h())->methods();
725 int nof_methods = methods->length();
726 HandleMark hm;
727 KlassHandle klass = _klass;
728 assert(nof_methods > 0, "at least one method must exist for interface to be in vtable");
729 Handle interface_loader (THREAD, InstanceKlass::cast(interf_h())->class_loader());
730 int ime_num = 0;
732 // Skip first Method* if it is a class initializer
733 int i = methods->at(0)->is_static_initializer() ? 1 : 0;
735 // m, method_name, method_signature, klass reset each loop so they
736 // don't need preserving across check_signature_loaders call
737 // methods needs a handle in case of gc from check_signature_loaders
738 for(; i < nof_methods; i++) {
739 Method* m = methods->at(i);
740 Symbol* method_name = m->name();
741 Symbol* method_signature = m->signature();
743 // This is same code as in Linkresolver::lookup_instance_method_in_klasses
744 Method* target = klass->uncached_lookup_method(method_name, method_signature);
745 while (target != NULL && target->is_static()) {
746 // continue with recursive lookup through the superclass
747 Klass* super = Klass::cast(target->method_holder())->super();
748 target = (super == NULL) ? (Method*)NULL : Klass::cast(super)->uncached_lookup_method(method_name, method_signature);
749 }
750 if (target == NULL || !target->is_public() || target->is_abstract()) {
751 // Entry do not resolve. Leave it empty
752 } else {
753 // Entry did resolve, check loader constraints before initializing
754 // if checkconstraints requested
755 methodHandle target_h (THREAD, target); // preserve across gc
756 if (checkconstraints) {
757 Handle method_holder_loader (THREAD, InstanceKlass::cast(target->method_holder())->class_loader());
758 if (method_holder_loader() != interface_loader()) {
759 ResourceMark rm(THREAD);
760 char* failed_type_name =
761 SystemDictionary::check_signature_loaders(method_signature,
762 method_holder_loader,
763 interface_loader,
764 true, CHECK);
765 if (failed_type_name != NULL) {
766 const char* msg = "loader constraint violation in interface "
767 "itable initialization: when resolving method \"%s\" the class"
768 " loader (instance of %s) of the current class, %s, "
769 "and the class loader (instance of %s) for interface "
770 "%s have different Class objects for the type %s "
771 "used in the signature";
772 char* sig = target_h()->name_and_sig_as_C_string();
773 const char* loader1 = SystemDictionary::loader_name(method_holder_loader());
774 char* current = klass->name()->as_C_string();
775 const char* loader2 = SystemDictionary::loader_name(interface_loader());
776 char* iface = InstanceKlass::cast(interf_h())->name()->as_C_string();
777 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
778 strlen(current) + strlen(loader2) + strlen(iface) +
779 strlen(failed_type_name);
780 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
781 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2,
782 iface, failed_type_name);
783 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
784 }
785 }
786 }
788 // ime may have moved during GC so recalculate address
789 itableOffsetEntry::method_entry(_klass(), method_table_offset)[ime_num].initialize(target_h());
790 }
791 // Progress to next entry
792 ime_num++;
793 }
794 }
796 // Update entry for specific Method*
797 void klassItable::initialize_with_method(Method* m) {
798 itableMethodEntry* ime = method_entry(0);
799 for(int i = 0; i < _size_method_table; i++) {
800 if (ime->method() == m) {
801 ime->initialize(m);
802 }
803 ime++;
804 }
805 }
807 void klassItable::adjust_method_entries(Method** old_methods, Method** new_methods,
808 int methods_length, bool * trace_name_printed) {
809 // search the itable for uses of either obsolete or EMCP methods
810 for (int j = 0; j < methods_length; j++) {
811 Method* old_method = old_methods[j];
812 Method* new_method = new_methods[j];
813 itableMethodEntry* ime = method_entry(0);
815 // The itable can describe more than one interface and the same
816 // method signature can be specified by more than one interface.
817 // This means we have to do an exhaustive search to find all the
818 // old_method references.
819 for (int i = 0; i < _size_method_table; i++) {
820 if (ime->method() == old_method) {
821 ime->initialize(new_method);
823 if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
824 if (!(*trace_name_printed)) {
825 // RC_TRACE_MESG macro has an embedded ResourceMark
826 RC_TRACE_MESG(("adjust: name=%s",
827 Klass::cast(old_method->method_holder())->external_name()));
828 *trace_name_printed = true;
829 }
830 // RC_TRACE macro has an embedded ResourceMark
831 RC_TRACE(0x00200000, ("itable method update: %s(%s)",
832 new_method->name()->as_C_string(),
833 new_method->signature()->as_C_string()));
834 }
835 // Cannot break because there might be another entry for this method
836 }
837 ime++;
838 }
839 }
840 }
843 // Setup
844 class InterfaceVisiterClosure : public StackObj {
845 public:
846 virtual void doit(Klass* intf, int method_count) = 0;
847 };
849 // Visit all interfaces with at-least one method (excluding <clinit>)
850 void visit_all_interfaces(Array<Klass*>* transitive_intf, InterfaceVisiterClosure *blk) {
851 // Handle array argument
852 for(int i = 0; i < transitive_intf->length(); i++) {
853 Klass* intf = transitive_intf->at(i);
854 assert(Klass::cast(intf)->is_interface(), "sanity check");
856 // Find no. of methods excluding a <clinit>
857 int method_count = InstanceKlass::cast(intf)->methods()->length();
858 if (method_count > 0) {
859 Method* m = InstanceKlass::cast(intf)->methods()->at(0);
860 assert(m != NULL && m->is_method(), "sanity check");
861 if (m->name() == vmSymbols::object_initializer_name()) {
862 method_count--;
863 }
864 }
866 // Only count interfaces with at least one method
867 if (method_count > 0) {
868 blk->doit(intf, method_count);
869 }
870 }
871 }
873 class CountInterfacesClosure : public InterfaceVisiterClosure {
874 private:
875 int _nof_methods;
876 int _nof_interfaces;
877 public:
878 CountInterfacesClosure() { _nof_methods = 0; _nof_interfaces = 0; }
880 int nof_methods() const { return _nof_methods; }
881 int nof_interfaces() const { return _nof_interfaces; }
883 void doit(Klass* intf, int method_count) { _nof_methods += method_count; _nof_interfaces++; }
884 };
886 class SetupItableClosure : public InterfaceVisiterClosure {
887 private:
888 itableOffsetEntry* _offset_entry;
889 itableMethodEntry* _method_entry;
890 address _klass_begin;
891 public:
892 SetupItableClosure(address klass_begin, itableOffsetEntry* offset_entry, itableMethodEntry* method_entry) {
893 _klass_begin = klass_begin;
894 _offset_entry = offset_entry;
895 _method_entry = method_entry;
896 }
898 itableMethodEntry* method_entry() const { return _method_entry; }
900 void doit(Klass* intf, int method_count) {
901 int offset = ((address)_method_entry) - _klass_begin;
902 _offset_entry->initialize(intf, offset);
903 _offset_entry++;
904 _method_entry += method_count;
905 }
906 };
908 int klassItable::compute_itable_size(Array<Klass*>* transitive_interfaces) {
909 // Count no of interfaces and total number of interface methods
910 CountInterfacesClosure cic;
911 visit_all_interfaces(transitive_interfaces, &cic);
913 // There's alway an extra itable entry so we can null-terminate it.
914 int itable_size = calc_itable_size(cic.nof_interfaces() + 1, cic.nof_methods());
916 // Statistics
917 update_stats(itable_size * HeapWordSize);
919 return itable_size;
920 }
923 // Fill out offset table and interface klasses into the itable space
924 void klassItable::setup_itable_offset_table(instanceKlassHandle klass) {
925 if (klass->itable_length() == 0) return;
926 assert(!klass->is_interface(), "Should have zero length itable");
928 // Count no of interfaces and total number of interface methods
929 CountInterfacesClosure cic;
930 visit_all_interfaces(klass->transitive_interfaces(), &cic);
931 int nof_methods = cic.nof_methods();
932 int nof_interfaces = cic.nof_interfaces();
934 // Add one extra entry so we can null-terminate the table
935 nof_interfaces++;
937 assert(compute_itable_size(klass->transitive_interfaces()) ==
938 calc_itable_size(nof_interfaces, nof_methods),
939 "mismatch calculation of itable size");
941 // Fill-out offset table
942 itableOffsetEntry* ioe = (itableOffsetEntry*)klass->start_of_itable();
943 itableMethodEntry* ime = (itableMethodEntry*)(ioe + nof_interfaces);
944 intptr_t* end = klass->end_of_itable();
945 assert((oop*)(ime + nof_methods) <= (oop*)klass->start_of_nonstatic_oop_maps(), "wrong offset calculation (1)");
946 assert((oop*)(end) == (oop*)(ime + nof_methods), "wrong offset calculation (2)");
948 // Visit all interfaces and initialize itable offset table
949 SetupItableClosure sic((address)klass(), ioe, ime);
950 visit_all_interfaces(klass->transitive_interfaces(), &sic);
952 #ifdef ASSERT
953 ime = sic.method_entry();
954 oop* v = (oop*) klass->end_of_itable();
955 assert( (oop*)(ime) == v, "wrong offset calculation (2)");
956 #endif
957 }
960 // m must be a method in an interface
961 int klassItable::compute_itable_index(Method* m) {
962 Klass* intf = m->method_holder();
963 assert(InstanceKlass::cast(intf)->is_interface(), "sanity check");
964 Array<Method*>* methods = InstanceKlass::cast(intf)->methods();
965 int index = 0;
966 while(methods->at(index) != m) {
967 index++;
968 assert(index < methods->length(), "should find index for resolve_invoke");
969 }
970 // Adjust for <clinit>, which is left out of table if first method
971 if (methods->length() > 0 && methods->at(0)->is_static_initializer()) {
972 index--;
973 }
974 return index;
975 }
978 // inverse to compute_itable_index
979 Method* klassItable::method_for_itable_index(Klass* intf, int itable_index) {
980 assert(InstanceKlass::cast(intf)->is_interface(), "sanity check");
981 Array<Method*>* methods = InstanceKlass::cast(intf)->methods();
983 int index = itable_index;
984 // Adjust for <clinit>, which is left out of table if first method
985 if (methods->length() > 0 && methods->at(0)->is_static_initializer()) {
986 index++;
987 }
989 if (itable_index < 0 || index >= methods->length())
990 return NULL; // help caller defend against bad indexes
992 Method* m = methods->at(index);
993 assert(compute_itable_index(m) == itable_index, "correct inverse");
995 return m;
996 }
998 void klassVtable::verify(outputStream* st, bool forced) {
999 // make sure table is initialized
1000 if (!Universe::is_fully_initialized()) return;
1001 #ifndef PRODUCT
1002 // avoid redundant verifies
1003 if (!forced && _verify_count == Universe::verify_count()) return;
1004 _verify_count = Universe::verify_count();
1005 #endif
1006 oop* end_of_obj = (oop*)_klass() + _klass()->size();
1007 oop* end_of_vtable = (oop *)&table()[_length];
1008 if (end_of_vtable > end_of_obj) {
1009 fatal(err_msg("klass %s: klass object too short (vtable extends beyond "
1010 "end)", _klass->internal_name()));
1011 }
1013 for (int i = 0; i < _length; i++) table()[i].verify(this, st);
1014 // verify consistency with superKlass vtable
1015 Klass* super = _klass->super();
1016 if (super != NULL) {
1017 InstanceKlass* sk = InstanceKlass::cast(super);
1018 klassVtable* vt = sk->vtable();
1019 for (int i = 0; i < vt->length(); i++) {
1020 verify_against(st, vt, i);
1021 }
1022 }
1023 }
1025 void klassVtable::verify_against(outputStream* st, klassVtable* vt, int index) {
1026 vtableEntry* vte = &vt->table()[index];
1027 if (vte->method()->name() != table()[index].method()->name() ||
1028 vte->method()->signature() != table()[index].method()->signature()) {
1029 fatal("mismatched name/signature of vtable entries");
1030 }
1031 }
1033 #ifndef PRODUCT
1034 void klassVtable::print() {
1035 ResourceMark rm;
1036 tty->print("klassVtable for klass %s (length %d):\n", _klass->internal_name(), length());
1037 for (int i = 0; i < length(); i++) {
1038 table()[i].print();
1039 tty->cr();
1040 }
1041 }
1042 #endif
1044 void vtableEntry::verify(klassVtable* vt, outputStream* st) {
1045 NOT_PRODUCT(FlagSetting fs(IgnoreLockingAssertions, true));
1046 assert(method() != NULL, "must have set method");
1047 method()->verify();
1048 // we sub_type, because it could be a miranda method
1049 if (!vt->klass()->is_subtype_of(method()->method_holder())) {
1050 #ifndef PRODUCT
1051 print();
1052 #endif
1053 fatal(err_msg("vtableEntry " PTR_FORMAT ": method is from subclass", this));
1054 }
1055 }
1057 #ifndef PRODUCT
1059 void vtableEntry::print() {
1060 ResourceMark rm;
1061 tty->print("vtableEntry %s: ", method()->name()->as_C_string());
1062 if (Verbose) {
1063 tty->print("m %#lx ", (address)method());
1064 }
1065 }
1067 class VtableStats : AllStatic {
1068 public:
1069 static int no_klasses; // # classes with vtables
1070 static int no_array_klasses; // # array classes
1071 static int no_instance_klasses; // # instanceKlasses
1072 static int sum_of_vtable_len; // total # of vtable entries
1073 static int sum_of_array_vtable_len; // total # of vtable entries in array klasses only
1074 static int fixed; // total fixed overhead in bytes
1075 static int filler; // overhead caused by filler bytes
1076 static int entries; // total bytes consumed by vtable entries
1077 static int array_entries; // total bytes consumed by array vtable entries
1079 static void do_class(Klass* k) {
1080 Klass* kl = k;
1081 klassVtable* vt = kl->vtable();
1082 if (vt == NULL) return;
1083 no_klasses++;
1084 if (kl->oop_is_instance()) {
1085 no_instance_klasses++;
1086 kl->array_klasses_do(do_class);
1087 }
1088 if (kl->oop_is_array()) {
1089 no_array_klasses++;
1090 sum_of_array_vtable_len += vt->length();
1091 }
1092 sum_of_vtable_len += vt->length();
1093 }
1095 static void compute() {
1096 SystemDictionary::classes_do(do_class);
1097 fixed = no_klasses * oopSize; // vtable length
1098 // filler size is a conservative approximation
1099 filler = oopSize * (no_klasses - no_instance_klasses) * (sizeof(InstanceKlass) - sizeof(ArrayKlass) - 1);
1100 entries = sizeof(vtableEntry) * sum_of_vtable_len;
1101 array_entries = sizeof(vtableEntry) * sum_of_array_vtable_len;
1102 }
1103 };
1105 int VtableStats::no_klasses = 0;
1106 int VtableStats::no_array_klasses = 0;
1107 int VtableStats::no_instance_klasses = 0;
1108 int VtableStats::sum_of_vtable_len = 0;
1109 int VtableStats::sum_of_array_vtable_len = 0;
1110 int VtableStats::fixed = 0;
1111 int VtableStats::filler = 0;
1112 int VtableStats::entries = 0;
1113 int VtableStats::array_entries = 0;
1115 void klassVtable::print_statistics() {
1116 ResourceMark rm;
1117 HandleMark hm;
1118 VtableStats::compute();
1119 tty->print_cr("vtable statistics:");
1120 tty->print_cr("%6d classes (%d instance, %d array)", VtableStats::no_klasses, VtableStats::no_instance_klasses, VtableStats::no_array_klasses);
1121 int total = VtableStats::fixed + VtableStats::filler + VtableStats::entries;
1122 tty->print_cr("%6d bytes fixed overhead (refs + vtable object header)", VtableStats::fixed);
1123 tty->print_cr("%6d bytes filler overhead", VtableStats::filler);
1124 tty->print_cr("%6d bytes for vtable entries (%d for arrays)", VtableStats::entries, VtableStats::array_entries);
1125 tty->print_cr("%6d bytes total", total);
1126 }
1128 bool klassVtable::check_no_old_entries() {
1129 // Check that there really is no entry
1130 for (int i = 0; i < length(); i++) {
1131 Method* m = unchecked_method_at(i);
1132 if (m != NULL) {
1133 if (!m->is_valid() || m->is_old()) {
1134 return false;
1135 }
1136 }
1137 }
1138 return true;
1139 }
1141 void klassVtable::dump_vtable() {
1142 tty->print_cr("vtable dump --");
1143 for (int i = 0; i < length(); i++) {
1144 Method* m = unchecked_method_at(i);
1145 if (m != NULL) {
1146 tty->print(" (%5d) ", i);
1147 m->access_flags().print_on(tty);
1148 tty->print(" -- ");
1149 m->print_name(tty);
1150 tty->cr();
1151 }
1152 }
1153 }
1155 bool klassItable::check_no_old_entries() {
1156 itableMethodEntry* ime = method_entry(0);
1157 for(int i = 0; i < _size_method_table; i++) {
1158 Method* m = ime->method();
1159 if (m != NULL && (!m->is_valid() || m->is_old())) return false;
1160 ime++;
1161 }
1162 return true;
1163 }
1165 int klassItable::_total_classes; // Total no. of classes with itables
1166 long klassItable::_total_size; // Total no. of bytes used for itables
1168 void klassItable::print_statistics() {
1169 tty->print_cr("itable statistics:");
1170 tty->print_cr("%6d classes with itables", _total_classes);
1171 tty->print_cr("%6d K uses for itables (average by class: %d bytes)", _total_size / K, _total_size / _total_classes);
1172 }
1174 #endif // PRODUCT