1 /*
2 * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/systemDictionary.hpp"
27 #include "classfile/vmSymbols.hpp"
28 #include "gc/shared/gcLocker.hpp"
29 #include "logging/log.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 return InstanceKlass::cast(_klass());
44 }
45
46
47 // this function computes the vtable size (including the size needed for miranda
48 // methods) and the number of miranda methods in this class.
49 // Note on Miranda methods: Let's say there is a class C that implements
50 // interface I, and none of C's superclasses implements I.
51 // Let's say there is an abstract method m in I that neither C
52 // nor any of its super classes implement (i.e there is no method of any access,
53 // with the same name and signature as m), then m is a Miranda method which is
54 // entered as a public abstract method in C's vtable. From then on it should
55 // treated as any other public method in C for method over-ride purposes.
56 void klassVtable::compute_vtable_size_and_num_mirandas(
57 int* vtable_length_ret, int* num_new_mirandas,
58 GrowableArray<Method*>* all_mirandas, const Klass* super,
59 Array<Method*>* methods, AccessFlags class_flags,
60 Handle classloader, Symbol* classname, Array<Klass*>* local_interfaces,
61 TRAPS) {
62 NoSafepointVerifier nsv;
63
64 // set up default result values
65 int vtable_length = 0;
66
67 // start off with super's vtable length
68 vtable_length = super == NULL ? 0 : super->vtable_length();
69
70 // go thru each method in the methods table to see if it needs a new entry
71 int len = methods->length();
72 for (int i = 0; i < len; i++) {
73 assert(methods->at(i)->is_method(), "must be a Method*");
74 methodHandle mh(THREAD, methods->at(i));
75
76 if (needs_new_vtable_entry(mh, super, classloader, classname, class_flags, THREAD)) {
77 vtable_length += vtableEntry::size(); // we need a new entry
78 }
79 }
80
81 GrowableArray<Method*> new_mirandas(20);
82 // compute the number of mirandas methods that must be added to the end
83 get_mirandas(&new_mirandas, all_mirandas, super, methods, NULL, local_interfaces);
84 *num_new_mirandas = new_mirandas.length();
85
86 // Interfaces do not need interface methods in their vtables
87 // This includes miranda methods and during later processing, default methods
88 if (!class_flags.is_interface()) {
89 vtable_length += *num_new_mirandas * vtableEntry::size();
90 }
91
92 if (Universe::is_bootstrapping() && vtable_length == 0 && classname != vmSymbols::java_lang____Value()) {
93 // array classes don't have their superclass set correctly during
94 // bootstrapping
95 vtable_length = Universe::base_vtable_size();
96 }
97
98 if (super == NULL && vtable_length != Universe::base_vtable_size()
99 && !class_flags.is_value_type()) {
100 if (Universe::is_bootstrapping()) {
101 // Someone is attempting to override java.lang.Object incorrectly on the
102 // bootclasspath. The JVM cannot recover from this error including throwing
103 // an exception
104 vm_exit_during_initialization("Incompatible definition of java.lang.Object");
105 } else {
106 // Someone is attempting to redefine java.lang.Object incorrectly. The
107 // only way this should happen is from
108 // SystemDictionary::resolve_from_stream(), which will detect this later
109 // and throw a security exception. So don't assert here to let
110 // the exception occur.
111 vtable_length = Universe::base_vtable_size();
112 }
113 }
114 assert(vtable_length % vtableEntry::size() == 0, "bad vtable length");
115 assert(vtable_length >= Universe::base_vtable_size()
116 || class_flags.is_value_type(), "vtable too small");
117
118 *vtable_length_ret = vtable_length;
119 }
120
121 int klassVtable::index_of(Method* m, int len) const {
122 assert(m->has_vtable_index(), "do not ask this of non-vtable methods");
123 return m->vtable_index();
124 }
125
126 // Copy super class's vtable to the first part (prefix) of this class's vtable,
127 // and return the number of entries copied. Expects that 'super' is the Java
128 // super class (arrays can have "array" super classes that must be skipped).
129 int klassVtable::initialize_from_super(KlassHandle super) {
130 if (super.is_null()) {
131 return 0;
132 } else {
133 // copy methods from superKlass
134 klassVtable* superVtable = super->vtable();
135 assert(superVtable->length() <= _length, "vtable too short");
136 #ifdef ASSERT
137 superVtable->verify(tty, true);
138 #endif
139 superVtable->copy_vtable_to(table());
140 if (log_develop_is_enabled(Trace, vtables)) {
141 ResourceMark rm;
142 log_develop_trace(vtables)("copy vtable from %s to %s size %d",
143 super->internal_name(), klass()->internal_name(),
144 _length);
145 }
146 return superVtable->length();
147 }
148 }
149
150 //
151 // Revised lookup semantics introduced 1.3 (Kestrel beta)
152 void klassVtable::initialize_vtable(bool checkconstraints, TRAPS) {
153
154 // Note: Arrays can have intermediate array supers. Use java_super to skip them.
155 KlassHandle super (THREAD, klass()->java_super());
156 int nofNewEntries = 0;
157
158 if (!klass()->is_array_klass()) {
159 ResourceMark rm(THREAD);
160 log_develop_debug(vtables)("Initializing: %s", _klass->name()->as_C_string());
161 }
162
163 #ifdef ASSERT
164 oop* end_of_obj = (oop*)_klass() + _klass()->size();
165 oop* end_of_vtable = (oop*)&table()[_length];
166 assert(end_of_vtable <= end_of_obj, "vtable extends beyond end");
167 #endif
168
169 if (Universe::is_bootstrapping()) {
170 // just clear everything
171 for (int i = 0; i < _length; i++) table()[i].clear();
172 return;
173 }
174
175 int super_vtable_len = initialize_from_super(super);
176 if (klass()->is_array_klass()) {
177 assert(super_vtable_len == _length, "arrays shouldn't introduce new methods");
178 } else {
179 assert(_klass->is_instance_klass(), "must be InstanceKlass");
180
181 Array<Method*>* methods = ik()->methods();
182 int len = methods->length();
183 int initialized = super_vtable_len;
184
185 // Check each of this class's methods against super;
186 // if override, replace in copy of super vtable, otherwise append to end
187 for (int i = 0; i < len; i++) {
188 // update_inherited_vtable can stop for gc - ensure using handles
189 HandleMark hm(THREAD);
190 assert(methods->at(i)->is_method(), "must be a Method*");
191 methodHandle mh(THREAD, methods->at(i));
192
193 bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, -1, checkconstraints, CHECK);
194
195 if (needs_new_entry) {
196 put_method_at(mh(), initialized);
197 mh()->set_vtable_index(initialized); // set primary vtable index
198 initialized++;
199 }
200 }
201
202 // update vtable with default_methods
203 Array<Method*>* default_methods = ik()->default_methods();
204 if (default_methods != NULL) {
205 len = default_methods->length();
206 if (len > 0) {
207 Array<int>* def_vtable_indices = NULL;
208 if ((def_vtable_indices = ik()->default_vtable_indices()) == NULL) {
209 def_vtable_indices = ik()->create_new_default_vtable_indices(len, CHECK);
210 } else {
211 assert(def_vtable_indices->length() == len, "reinit vtable len?");
212 }
213 for (int i = 0; i < len; i++) {
214 HandleMark hm(THREAD);
215 assert(default_methods->at(i)->is_method(), "must be a Method*");
216 methodHandle mh(THREAD, default_methods->at(i));
217
218 bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, i, checkconstraints, CHECK);
219
220 // needs new entry
221 if (needs_new_entry) {
222 put_method_at(mh(), initialized);
223 def_vtable_indices->at_put(i, initialized); //set vtable index
224 initialized++;
225 }
226 }
227 }
228 }
229
230 // add miranda methods; it will also return the updated initialized
231 // Interfaces do not need interface methods in their vtables
232 // This includes miranda methods and during later processing, default methods
233 if (!ik()->is_interface()) {
234 initialized = fill_in_mirandas(initialized);
235 }
236
237 // In class hierarchies where the accessibility is not increasing (i.e., going from private ->
238 // package_private -> public/protected), the vtable might actually be smaller than our initial
239 // calculation.
240 assert(initialized <= _length, "vtable initialization failed");
241 for(;initialized < _length; initialized++) {
242 put_method_at(NULL, initialized);
243 }
244 NOT_PRODUCT(verify(tty, true));
245 }
246 }
247
248 // Called for cases where a method does not override its superclass' vtable entry
249 // For bytecodes not produced by javac together it is possible that a method does not override
250 // the superclass's method, but might indirectly override a super-super class's vtable entry
251 // If none found, return a null superk, else return the superk of the method this does override
252 // For public and protected methods: if they override a superclass, they will
253 // also be overridden themselves appropriately.
254 // Private methods do not override and are not overridden.
255 // Package Private methods are trickier:
256 // e.g. P1.A, pub m
257 // P2.B extends A, package private m
258 // P1.C extends B, public m
259 // P1.C.m needs to override P1.A.m and can not override P2.B.m
260 // Therefore: all package private methods need their own vtable entries for
261 // them to be the root of an inheritance overriding decision
262 // Package private methods may also override other vtable entries
263 InstanceKlass* klassVtable::find_transitive_override(InstanceKlass* initialsuper, methodHandle target_method,
264 int vtable_index, Handle target_loader, Symbol* target_classname, Thread * THREAD) {
265 InstanceKlass* superk = initialsuper;
266 while (superk != NULL && superk->super() != NULL) {
267 InstanceKlass* supersuperklass = InstanceKlass::cast(superk->super());
268 klassVtable* ssVtable = supersuperklass->vtable();
269 if (vtable_index < ssVtable->length()) {
270 Method* super_method = ssVtable->method_at(vtable_index);
271 #ifndef PRODUCT
272 Symbol* name= target_method()->name();
273 Symbol* signature = target_method()->signature();
274 assert(super_method->name() == name && super_method->signature() == signature, "vtable entry name/sig mismatch");
275 #endif
276 if (supersuperklass->is_override(super_method, target_loader, target_classname, THREAD)) {
277 if (log_develop_is_enabled(Trace, vtables)) {
278 ResourceMark rm(THREAD);
279 outputStream* logst = LogHandle(vtables)::trace_stream();
280 char* sig = target_method()->name_and_sig_as_C_string();
281 logst->print("transitive overriding superclass %s with %s::%s index %d, original flags: ",
282 supersuperklass->internal_name(),
283 _klass->internal_name(), sig, vtable_index);
284 super_method->print_linkage_flags(logst);
285 logst->print("overriders flags: ");
286 target_method->print_linkage_flags(logst);
287 logst->cr();
288 }
289
290 break; // return found superk
291 }
292 } else {
293 // super class has no vtable entry here, stop transitive search
294 superk = (InstanceKlass*)NULL;
295 break;
296 }
297 // if no override found yet, continue to search up
298 superk = superk->super() == NULL ? NULL : InstanceKlass::cast(superk->super());
299 }
300
301 return superk;
302 }
303
304 static void log_vtables(int i, bool overrides, methodHandle target_method,
305 KlassHandle target_klass, Method* super_method,
306 Thread* thread) {
307 #ifndef PRODUCT
308 if (log_develop_is_enabled(Trace, vtables)) {
309 ResourceMark rm(thread);
310 outputStream* logst = LogHandle(vtables)::trace_stream();
311 char* sig = target_method()->name_and_sig_as_C_string();
312 if (overrides) {
313 logst->print("overriding with %s::%s index %d, original flags: ",
314 target_klass->internal_name(), sig, i);
315 } else {
316 logst->print("NOT overriding with %s::%s index %d, original flags: ",
317 target_klass->internal_name(), sig, i);
318 }
319 super_method->print_linkage_flags(logst);
320 logst->print("overriders flags: ");
321 target_method->print_linkage_flags(logst);
322 logst->cr();
323 }
324 #endif
325 }
326
327 // Update child's copy of super vtable for overrides
328 // OR return true if a new vtable entry is required.
329 // Only called for InstanceKlass's, i.e. not for arrays
330 // If that changed, could not use _klass as handle for klass
331 bool klassVtable::update_inherited_vtable(InstanceKlass* klass, methodHandle target_method,
332 int super_vtable_len, int default_index,
333 bool checkconstraints, TRAPS) {
334 ResourceMark rm;
335 bool allocate_new = true;
336 assert(klass->is_instance_klass(), "must be InstanceKlass");
337
338 Array<int>* def_vtable_indices = NULL;
339 bool is_default = false;
340 // default methods are concrete methods in superinterfaces which are added to the vtable
341 // with their real method_holder
342 // Since vtable and itable indices share the same storage, don't touch
343 // the default method's real vtable/itable index
344 // default_vtable_indices stores the vtable value relative to this inheritor
345 if (default_index >= 0 ) {
346 is_default = true;
347 def_vtable_indices = klass->default_vtable_indices();
348 assert(def_vtable_indices != NULL, "def vtable alloc?");
349 assert(default_index <= def_vtable_indices->length(), "def vtable len?");
350 } else {
351 assert(klass == target_method()->method_holder(), "caller resp.");
352 // Initialize the method's vtable index to "nonvirtual".
353 // If we allocate a vtable entry, we will update it to a non-negative number.
354 target_method()->set_vtable_index(Method::nonvirtual_vtable_index);
355 }
356
357 // Static and <init> methods are never in
358 if (target_method()->is_static() || target_method()->name() == vmSymbols::object_initializer_name()) {
359 return false;
360 }
361
362 if (target_method->is_final_method(klass->access_flags())) {
363 // a final method never needs a new entry; final methods can be statically
364 // resolved and they have to be present in the vtable only if they override
365 // a super's method, in which case they re-use its entry
366 allocate_new = false;
367 } else if (klass->is_interface()) {
368 allocate_new = false; // see note below in needs_new_vtable_entry
369 // An interface never allocates new vtable slots, only inherits old ones.
370 // This method will either be assigned its own itable index later,
371 // or be assigned an inherited vtable index in the loop below.
372 // default methods inherited by classes store their vtable indices
373 // in the inheritor's default_vtable_indices
374 // default methods inherited by interfaces may already have a
375 // valid itable index, if so, don't change it
376 // overpass methods in an interface will be assigned an itable index later
377 // by an inheriting class
378 if (!is_default || !target_method()->has_itable_index()) {
379 target_method()->set_vtable_index(Method::pending_itable_index);
380 }
381 }
382
383 // we need a new entry if there is no superclass
384 if (klass->super() == NULL) {
385 return allocate_new;
386 }
387
388 // private methods in classes always have a new entry in the vtable
389 // specification interpretation since classic has
390 // private methods not overriding
391 // JDK8 adds private methods in interfaces which require invokespecial
392 if (target_method()->is_private()) {
393 return allocate_new;
394 }
395
396 // search through the vtable and update overridden entries
397 // Since check_signature_loaders acquires SystemDictionary_lock
398 // which can block for gc, once we are in this loop, use handles
399 // For classfiles built with >= jdk7, we now look for transitive overrides
400
401 Symbol* name = target_method()->name();
402 Symbol* signature = target_method()->signature();
403
404 KlassHandle target_klass(THREAD, target_method()->method_holder());
405 if (target_klass == NULL) {
406 target_klass = _klass;
407 }
408
409 Handle target_loader(THREAD, target_klass->class_loader());
410
411 Symbol* target_classname = target_klass->name();
412 for(int i = 0; i < super_vtable_len; i++) {
413 Method* super_method = method_at(i);
414 // Check if method name matches
415 if (super_method->name() == name && super_method->signature() == signature) {
416
417 // get super_klass for method_holder for the found method
418 InstanceKlass* super_klass = super_method->method_holder();
419
420 // Whether the method is being overridden
421 bool overrides = false;
422
423 // private methods are also never overridden
424 if (!super_method->is_private() &&
425 (is_default
426 || ((super_klass->is_override(super_method, target_loader, target_classname, THREAD))
427 || ((klass->major_version() >= VTABLE_TRANSITIVE_OVERRIDE_VERSION)
428 && ((super_klass = find_transitive_override(super_klass,
429 target_method, i, target_loader,
430 target_classname, THREAD))
431 != (InstanceKlass*)NULL)))))
432 {
433 // Package private methods always need a new entry to root their own
434 // overriding. They may also override other methods.
435 if (!target_method()->is_package_private()) {
436 allocate_new = false;
437 }
438
439 if (checkconstraints) {
440 // Override vtable entry if passes loader constraint check
441 // if loader constraint checking requested
442 // No need to visit his super, since he and his super
443 // have already made any needed loader constraints.
444 // Since loader constraints are transitive, it is enough
445 // to link to the first super, and we get all the others.
446 Handle super_loader(THREAD, super_klass->class_loader());
447
448 if (target_loader() != super_loader()) {
449 ResourceMark rm(THREAD);
450 Symbol* failed_type_symbol =
451 SystemDictionary::check_signature_loaders(signature, target_loader,
452 super_loader, true,
453 CHECK_(false));
454 if (failed_type_symbol != NULL) {
455 const char* msg = "loader constraint violation: when resolving "
456 "overridden method \"%s\" the class loader (instance"
457 " of %s) of the current class, %s, and its superclass loader "
458 "(instance of %s), have different Class objects for the type "
459 "%s used in the signature";
460 char* sig = target_method()->name_and_sig_as_C_string();
461 const char* loader1 = SystemDictionary::loader_name(target_loader());
462 char* current = target_klass->name()->as_C_string();
463 const char* loader2 = SystemDictionary::loader_name(super_loader());
464 char* failed_type_name = failed_type_symbol->as_C_string();
465 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
466 strlen(current) + strlen(loader2) + strlen(failed_type_name);
467 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
468 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2,
469 failed_type_name);
470 THROW_MSG_(vmSymbols::java_lang_LinkageError(), buf, false);
471 }
472 }
473 }
474
475 put_method_at(target_method(), i);
476 overrides = true;
477 if (!is_default) {
478 target_method()->set_vtable_index(i);
479 } else {
480 if (def_vtable_indices != NULL) {
481 def_vtable_indices->at_put(default_index, i);
482 }
483 assert(super_method->is_default_method() || super_method->is_overpass()
484 || super_method->is_abstract(), "default override error");
485 }
486 } else {
487 overrides = false;
488 }
489 log_vtables(i, overrides, target_method, target_klass, super_method, THREAD);
490 }
491 }
492 return allocate_new;
493 }
494
495 void klassVtable::put_method_at(Method* m, int index) {
496 if (log_develop_is_enabled(Trace, vtables)) {
497 ResourceMark rm;
498 outputStream* logst = LogHandle(vtables)::trace_stream();
499 const char* sig = (m != NULL) ? m->name_and_sig_as_C_string() : "<NULL>";
500 logst->print("adding %s at index %d, flags: ", sig, index);
501 if (m != NULL) {
502 m->print_linkage_flags(logst);
503 }
504 logst->cr();
505 }
506 table()[index].set(m);
507 }
508
509 // Find out if a method "m" with superclass "super", loader "classloader" and
510 // name "classname" needs a new vtable entry. Let P be a class package defined
511 // by "classloader" and "classname".
512 // NOTE: The logic used here is very similar to the one used for computing
513 // the vtables indices for a method. We cannot directly use that function because,
514 // we allocate the InstanceKlass at load time, and that requires that the
515 // superclass has been loaded.
516 // However, the vtable entries are filled in at link time, and therefore
517 // the superclass' vtable may not yet have been filled in.
518 bool klassVtable::needs_new_vtable_entry(methodHandle target_method,
519 const Klass* super,
520 Handle classloader,
521 Symbol* classname,
522 AccessFlags class_flags,
523 TRAPS) {
524 if (class_flags.is_interface()) {
525 // Interfaces do not use vtables, except for java.lang.Object methods,
526 // so there is no point to assigning
527 // a vtable index to any of their local methods. If we refrain from doing this,
528 // we can use Method::_vtable_index to hold the itable index
529 return false;
530 }
531
532 if (target_method->is_final_method(class_flags) ||
533 // a final method never needs a new entry; final methods can be statically
534 // resolved and they have to be present in the vtable only if they override
535 // a super's method, in which case they re-use its entry
536 (target_method()->is_static()) ||
537 // static methods don't need to be in vtable
538 (target_method()->name() == vmSymbols::object_initializer_name())
539 // <init> is never called dynamically-bound
540 ) {
541 return false;
542 }
543
544 // Concrete interface methods do not need new entries, they override
545 // abstract method entries using default inheritance rules
546 if (target_method()->method_holder() != NULL &&
547 target_method()->method_holder()->is_interface() &&
548 !target_method()->is_abstract() ) {
549 return false;
550 }
551
552 // we need a new entry if there is no superclass
553 if (super == NULL) {
554 return true;
555 }
556
557 // private methods in classes always have a new entry in the vtable
558 // specification interpretation since classic has
559 // private methods not overriding
560 // JDK8 adds private methods in interfaces which require invokespecial
561 if (target_method()->is_private()) {
562 return true;
563 }
564
565 // Package private methods always need a new entry to root their own
566 // overriding. This allows transitive overriding to work.
567 if (target_method()->is_package_private()) {
568 return true;
569 }
570
571 // search through the super class hierarchy to see if we need
572 // a new entry
573 ResourceMark rm;
574 Symbol* name = target_method()->name();
575 Symbol* signature = target_method()->signature();
576 const Klass* k = super;
577 Method* super_method = NULL;
578 InstanceKlass *holder = NULL;
579 Method* recheck_method = NULL;
580 while (k != NULL) {
581 // lookup through the hierarchy for a method with matching name and sign.
582 super_method = InstanceKlass::cast(k)->lookup_method(name, signature);
583 if (super_method == NULL) {
584 break; // we still have to search for a matching miranda method
585 }
586 // get the class holding the matching method
587 // make sure you use that class for is_override
588 InstanceKlass* superk = super_method->method_holder();
589 // we want only instance method matches
590 // pretend private methods are not in the super vtable
591 // since we do override around them: e.g. a.m pub/b.m private/c.m pub,
592 // ignore private, c.m pub does override a.m pub
593 // For classes that were not javac'd together, we also do transitive overriding around
594 // methods that have less accessibility
595 if ((!super_method->is_static()) &&
596 (!super_method->is_private())) {
597 if (superk->is_override(super_method, classloader, classname, THREAD)) {
598 return false;
599 // else keep looking for transitive overrides
600 }
601 }
602
603 // Start with lookup result and continue to search up
604 k = superk->super(); // haven't found an override match yet; continue to look
605 }
606
607 // if the target method is public or protected it may have a matching
608 // miranda method in the super, whose entry it should re-use.
609 // Actually, to handle cases that javac would not generate, we need
610 // this check for all access permissions.
611 const InstanceKlass *sk = InstanceKlass::cast(super);
612 if (sk->has_miranda_methods()) {
613 if (sk->lookup_method_in_all_interfaces(name, signature, Klass::find_defaults) != NULL) {
614 return false; // found a matching miranda; we do not need a new entry
615 }
616 }
617 return true; // found no match; we need a new entry
618 }
619
620 // Support for miranda methods
621
622 // get the vtable index of a miranda method with matching "name" and "signature"
623 int klassVtable::index_of_miranda(Symbol* name, Symbol* signature) {
624 // search from the bottom, might be faster
625 for (int i = (length() - 1); i >= 0; i--) {
626 Method* m = table()[i].method();
627 if (is_miranda_entry_at(i) &&
628 m->name() == name && m->signature() == signature) {
629 return i;
630 }
631 }
632 return Method::invalid_vtable_index;
633 }
634
635 // check if an entry at an index is miranda
636 // requires that method m at entry be declared ("held") by an interface.
637 bool klassVtable::is_miranda_entry_at(int i) {
638 Method* m = method_at(i);
639 Klass* method_holder = m->method_holder();
640 InstanceKlass *mhk = InstanceKlass::cast(method_holder);
641
642 // miranda methods are public abstract instance interface methods in a class's vtable
643 if (mhk->is_interface()) {
644 assert(m->is_public(), "should be public");
645 assert(ik()->implements_interface(method_holder, false) , "this class should implement the interface");
646 if (is_miranda(m, ik()->methods(), ik()->default_methods(), ik()->super())) {
647 return true;
648 }
649 }
650 return false;
651 }
652
653 // Check if a method is a miranda method, given a class's methods array,
654 // its default_method table and its super class.
655 // "Miranda" means an abstract non-private method that would not be
656 // overridden for the local class.
657 // A "miranda" method should only include non-private interface
658 // instance methods, i.e. not private methods, not static methods,
659 // not default methods (concrete interface methods), not overpass methods.
660 // If a given class already has a local (including overpass) method, a
661 // default method, or any of its superclasses has the same which would have
662 // overridden an abstract method, then this is not a miranda method.
663 //
664 // Miranda methods are checked multiple times.
665 // Pass 1: during class load/class file parsing: before vtable size calculation:
666 // include superinterface abstract and default methods (non-private instance).
667 // We include potential default methods to give them space in the vtable.
668 // During the first run, the current instanceKlass has not yet been
669 // created, the superclasses and superinterfaces do have instanceKlasses
670 // but may not have vtables, the default_methods list is empty, no overpasses.
671 // This is seen by default method creation.
672 //
673 // Pass 2: recalculated during vtable initialization: only include abstract methods.
674 // The goal of pass 2 is to walk through the superinterfaces to see if any of
675 // the superinterface methods (which were all abstract pre-default methods)
676 // need to be added to the vtable.
677 // With the addition of default methods, we have three new challenges:
678 // overpasses, static interface methods and private interface methods.
679 // Static and private interface methods do not get added to the vtable and
680 // are not seen by the method resolution process, so we skip those.
681 // Overpass methods are already in the vtable, so vtable lookup will
682 // find them and we don't need to add a miranda method to the end of
683 // the vtable. So we look for overpass methods and if they are found we
684 // return false. Note that we inherit our superclasses vtable, so
685 // the superclass' search also needs to use find_overpass so that if
686 // one is found we return false.
687 // False means - we don't need a miranda method added to the vtable.
688 //
689 // During the second run, default_methods is set up, so concrete methods from
690 // superinterfaces with matching names/signatures to default_methods are already
691 // in the default_methods list and do not need to be appended to the vtable
692 // as mirandas. Abstract methods may already have been handled via
693 // overpasses - either local or superclass overpasses, which may be
694 // in the vtable already.
695 //
696 // Pass 3: They are also checked by link resolution and selection,
697 // for invocation on a method (not interface method) reference that
698 // resolves to a method with an interface as its method_holder.
699 // Used as part of walking from the bottom of the vtable to find
700 // the vtable index for the miranda method.
701 //
702 // Part of the Miranda Rights in the US mean that if you do not have
703 // an attorney one will be appointed for you.
704 bool klassVtable::is_miranda(Method* m, Array<Method*>* class_methods,
705 Array<Method*>* default_methods, const Klass* super) {
706 if (m->is_static() || m->is_private() || m->is_overpass()) {
707 return false;
708 }
709 Symbol* name = m->name();
710 Symbol* signature = m->signature();
711
712 // First look in local methods to see if already covered
713 if (InstanceKlass::find_local_method(class_methods, name, signature,
714 Klass::find_overpass, Klass::skip_static, Klass::skip_private) != NULL)
715 {
716 return false;
717 }
718
719 // Check local default methods
720 if ((default_methods != NULL) &&
721 (InstanceKlass::find_method(default_methods, name, signature) != NULL))
722 {
723 return false;
724 }
725
726 // Iterate on all superclasses, which should be InstanceKlasses.
727 // Note that we explicitly look for overpasses at each level.
728 // Overpasses may or may not exist for supers for pass 1,
729 // they should have been created for pass 2 and later.
730
731 for (const Klass* cursuper = super; cursuper != NULL; cursuper = cursuper->super())
732 {
733 if (InstanceKlass::cast(cursuper)->find_local_method(name, signature,
734 Klass::find_overpass, Klass::skip_static, Klass::skip_private) != NULL) {
735 return false;
736 }
737 }
738
739 return true;
740 }
741
742 // Scans current_interface_methods for miranda methods that do not
743 // already appear in new_mirandas, or default methods, and are also not defined-and-non-private
744 // in super (superclass). These mirandas are added to all_mirandas if it is
745 // not null; in addition, those that are not duplicates of miranda methods
746 // inherited by super from its interfaces are added to new_mirandas.
747 // Thus, new_mirandas will be the set of mirandas that this class introduces,
748 // all_mirandas will be the set of all mirandas applicable to this class
749 // including all defined in superclasses.
750 void klassVtable::add_new_mirandas_to_lists(
751 GrowableArray<Method*>* new_mirandas, GrowableArray<Method*>* all_mirandas,
752 Array<Method*>* current_interface_methods, Array<Method*>* class_methods,
753 Array<Method*>* default_methods, const Klass* super) {
754
755 // iterate thru the current interface's method to see if it a miranda
756 int num_methods = current_interface_methods->length();
757 for (int i = 0; i < num_methods; i++) {
758 Method* im = current_interface_methods->at(i);
759 bool is_duplicate = false;
760 int num_of_current_mirandas = new_mirandas->length();
761 // check for duplicate mirandas in different interfaces we implement
762 for (int j = 0; j < num_of_current_mirandas; j++) {
763 Method* miranda = new_mirandas->at(j);
764 if ((im->name() == miranda->name()) &&
765 (im->signature() == miranda->signature())) {
766 is_duplicate = true;
767 break;
768 }
769 }
770
771 if (!is_duplicate) { // we don't want duplicate miranda entries in the vtable
772 if (is_miranda(im, class_methods, default_methods, super)) { // is it a miranda at all?
773 const InstanceKlass *sk = InstanceKlass::cast(super);
774 // check if it is a duplicate of a super's miranda
775 if (sk->lookup_method_in_all_interfaces(im->name(), im->signature(), Klass::find_defaults) == NULL) {
776 new_mirandas->append(im);
777 }
778 if (all_mirandas != NULL) {
779 all_mirandas->append(im);
780 }
781 }
782 }
783 }
784 }
785
786 void klassVtable::get_mirandas(GrowableArray<Method*>* new_mirandas,
787 GrowableArray<Method*>* all_mirandas,
788 const Klass* super,
789 Array<Method*>* class_methods,
790 Array<Method*>* default_methods,
791 Array<Klass*>* local_interfaces) {
792 assert((new_mirandas->length() == 0) , "current mirandas must be 0");
793
794 // iterate thru the local interfaces looking for a miranda
795 int num_local_ifs = local_interfaces->length();
796 for (int i = 0; i < num_local_ifs; i++) {
797 InstanceKlass *ik = InstanceKlass::cast(local_interfaces->at(i));
798 add_new_mirandas_to_lists(new_mirandas, all_mirandas,
799 ik->methods(), class_methods,
800 default_methods, super);
801 // iterate thru each local's super interfaces
802 Array<Klass*>* super_ifs = ik->transitive_interfaces();
803 int num_super_ifs = super_ifs->length();
804 for (int j = 0; j < num_super_ifs; j++) {
805 InstanceKlass *sik = InstanceKlass::cast(super_ifs->at(j));
806 add_new_mirandas_to_lists(new_mirandas, all_mirandas,
807 sik->methods(), class_methods,
808 default_methods, super);
809 }
810 }
811 }
812
813 // Discover miranda methods ("miranda" = "interface abstract, no binding"),
814 // and append them into the vtable starting at index initialized,
815 // return the new value of initialized.
816 // Miranda methods use vtable entries, but do not get assigned a vtable_index
817 // The vtable_index is discovered by searching from the end of the vtable
818 int klassVtable::fill_in_mirandas(int initialized) {
819 GrowableArray<Method*> mirandas(20);
820 get_mirandas(&mirandas, NULL, ik()->super(), ik()->methods(),
821 ik()->default_methods(), ik()->local_interfaces());
822 for (int i = 0; i < mirandas.length(); i++) {
823 if (log_develop_is_enabled(Trace, vtables)) {
824 Method* meth = mirandas.at(i);
825 ResourceMark rm(Thread::current());
826 outputStream* logst = LogHandle(vtables)::trace_stream();
827 if (meth != NULL) {
828 char* sig = meth->name_and_sig_as_C_string();
829 logst->print("fill in mirandas with %s index %d, flags: ",
830 sig, initialized);
831 meth->print_linkage_flags(logst);
832 logst->cr();
833 }
834 }
835 put_method_at(mirandas.at(i), initialized);
836 ++initialized;
837 }
838 return initialized;
839 }
840
841 // Copy this class's vtable to the vtable beginning at start.
842 // Used to copy superclass vtable to prefix of subclass's vtable.
843 void klassVtable::copy_vtable_to(vtableEntry* start) {
844 Copy::disjoint_words((HeapWord*)table(), (HeapWord*)start, _length * vtableEntry::size());
845 }
846
847 #if INCLUDE_JVMTI
848 bool klassVtable::adjust_default_method(int vtable_index, Method* old_method, Method* new_method) {
849 // If old_method is default, find this vtable index in default_vtable_indices
850 // and replace that method in the _default_methods list
851 bool updated = false;
852
853 Array<Method*>* default_methods = ik()->default_methods();
854 if (default_methods != NULL) {
855 int len = default_methods->length();
856 for (int idx = 0; idx < len; idx++) {
857 if (vtable_index == ik()->default_vtable_indices()->at(idx)) {
858 if (default_methods->at(idx) == old_method) {
859 default_methods->at_put(idx, new_method);
860 updated = true;
861 }
862 break;
863 }
864 }
865 }
866 return updated;
867 }
868
869 // search the vtable for uses of either obsolete or EMCP methods
870 void klassVtable::adjust_method_entries(InstanceKlass* holder, bool * trace_name_printed) {
871 int prn_enabled = 0;
872 for (int index = 0; index < length(); index++) {
873 Method* old_method = unchecked_method_at(index);
874 if (old_method == NULL || old_method->method_holder() != holder || !old_method->is_old()) {
875 continue; // skip uninteresting entries
876 }
877 assert(!old_method->is_deleted(), "vtable methods may not be deleted");
878
879 Method* new_method = holder->method_with_idnum(old_method->orig_method_idnum());
880
881 assert(new_method != NULL, "method_with_idnum() should not be NULL");
882 assert(old_method != new_method, "sanity check");
883
884 put_method_at(new_method, index);
885 // For default methods, need to update the _default_methods array
886 // which can only have one method entry for a given signature
887 bool updated_default = false;
888 if (old_method->is_default_method()) {
889 updated_default = adjust_default_method(index, old_method, new_method);
890 }
891
892 if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
893 if (!(*trace_name_printed)) {
894 // RC_TRACE_MESG macro has an embedded ResourceMark
895 RC_TRACE_MESG(("adjust: klassname=%s for methods from name=%s",
896 klass()->external_name(),
897 old_method->method_holder()->external_name()));
898 *trace_name_printed = true;
899 }
900 // RC_TRACE macro has an embedded ResourceMark
901 RC_TRACE(0x00100000, ("vtable method update: %s(%s), updated default = %s",
902 new_method->name()->as_C_string(),
903 new_method->signature()->as_C_string(),
904 updated_default ? "true" : "false"));
905 }
906 }
907 }
908
909 // a vtable should never contain old or obsolete methods
910 bool klassVtable::check_no_old_or_obsolete_entries() {
911 for (int i = 0; i < length(); i++) {
912 Method* m = unchecked_method_at(i);
913 if (m != NULL &&
914 (NOT_PRODUCT(!m->is_valid() ||) m->is_old() || m->is_obsolete())) {
915 return false;
916 }
917 }
918 return true;
919 }
920
921 void klassVtable::dump_vtable() {
922 tty->print_cr("vtable dump --");
923 for (int i = 0; i < length(); i++) {
924 Method* m = unchecked_method_at(i);
925 if (m != NULL) {
926 tty->print(" (%5d) ", i);
927 m->access_flags().print_on(tty);
928 if (m->is_default_method()) {
929 tty->print("default ");
930 }
931 if (m->is_overpass()) {
932 tty->print("overpass");
933 }
934 tty->print(" -- ");
935 m->print_name(tty);
936 tty->cr();
937 }
938 }
939 }
940 #endif // INCLUDE_JVMTI
941
942 // CDS/RedefineClasses support - clear vtables so they can be reinitialized
943 void klassVtable::clear_vtable() {
944 for (int i = 0; i < _length; i++) table()[i].clear();
945 }
946
947 bool klassVtable::is_initialized() {
948 return _length == 0 || table()[0].method() != NULL;
949 }
950
951 //-----------------------------------------------------------------------------------------
952 // Itable code
953
954 // Initialize a itableMethodEntry
955 void itableMethodEntry::initialize(Method* m) {
956 if (m == NULL) return;
957
958 _method = m;
959 }
960
961 klassItable::klassItable(instanceKlassHandle klass) {
962 _klass = klass;
963
964 if (klass->itable_length() > 0) {
965 itableOffsetEntry* offset_entry = (itableOffsetEntry*)klass->start_of_itable();
966 if (offset_entry != NULL && offset_entry->interface_klass() != NULL) { // Check that itable is initialized
967 // First offset entry points to the first method_entry
968 intptr_t* method_entry = (intptr_t *)(((address)klass()) + offset_entry->offset());
969 intptr_t* end = klass->end_of_itable();
970
971 #ifdef ASSERT
972 intptr_t* p0 = (intptr_t*) klass();
973 intptr_t* p1 = (intptr_t*) klass() + klass->size();
974 assert(method_entry > p0, "");
975 assert(method_entry < p1, "");
976 assert(end > p0, "");
977 assert(end <= p1, "");
978 #endif //ASSERT
979
980 _table_offset = (intptr_t*)offset_entry - (intptr_t*)klass();
981 _size_offset_table = (method_entry - ((intptr_t*)offset_entry)) / itableOffsetEntry::size();
982 _size_method_table = (end - method_entry) / itableMethodEntry::size();
983 assert(_table_offset >= 0 && _size_offset_table >= 0 && _size_method_table >= 0, "wrong computation");
984 assert(this->offset_entry(_size_offset_table - 1)->interface_klass() == NULL, "end marker exists");
985 return;
986 }
987 }
988
989 // The length of the itable was either zero, or it has not yet been initialized.
990 _table_offset = 0;
991 _size_offset_table = 0;
992 _size_method_table = 0;
993 }
994
995 #ifndef PRODUCT
996 bool klassItable::bounds_check_offset(const itableOffsetEntry* ioe) const {
997 const char* bad = NULL;
998 if (_table_offset == 0) {
999 if (ioe == (itableOffsetEntry*) _klass->start_of_itable())
1000 return true;
1001 bad = "outside empty";
1002 } else if ((intptr_t*)ioe < vtable_start()) {
1003 bad = "before";
1004 } else if ((intptr_t*)ioe >= vtable_end()) {
1005 bad = "after";
1006 } else {
1007 return true;
1008 }
1009 tty->print_cr("%s itable offsets: " INTPTR_FORMAT " [" INTPTR_FORMAT ".." INTPTR_FORMAT "]",
1010 bad, (intptr_t)ioe, (intptr_t)vtable_start(), (intptr_t)vtable_end());
1011 Verbose = WizardMode = true; klass()->print(); //@@
1012 return false;
1013 }
1014 bool klassItable::bounds_check_method(const itableMethodEntry* moe) const {
1015 const char* bad = NULL;
1016 if ((intptr_t*)moe < method_start()) {
1017 bad = "before";
1018 } else if ((intptr_t*)moe >= method_end()) {
1019 bad = "after";
1020 } else {
1021 return true;
1022 }
1023 tty->print_cr("%s itable methods: " INTPTR_FORMAT " [" INTPTR_FORMAT ".." INTPTR_FORMAT "]",
1024 bad, (intptr_t)moe, (intptr_t)method_start(), (intptr_t)method_end());
1025 Verbose = WizardMode = true; klass()->print();
1026 return false;
1027 }
1028 #endif //PRODUCT
1029
1030 static int initialize_count = 0;
1031
1032 // Initialization
1033 void klassItable::initialize_itable(bool checkconstraints, TRAPS) {
1034 if (_klass->is_interface()) {
1035 // This needs to go after vtable indices are assigned but
1036 // before implementors need to know the number of itable indices.
1037 assign_itable_indices_for_interface(_klass());
1038 }
1039
1040 // Cannot be setup doing bootstrapping, interfaces don't have
1041 // itables (except in the case self itables for intefaces used as "extra_super"),
1042 // and klass with only ones entry have empty itables
1043 if (Universe::is_bootstrapping() || !_klass->has_itable_entries())
1044 return;
1045
1046 // There's always an extra itable entry so we can null-terminate it.
1047 guarantee(size_offset_table() >= 1, "too small");
1048 int num_interfaces = size_offset_table() - 1;
1049 if (num_interfaces > 0) {
1050 log_develop_debug(itables)("%3d: Initializing itables for %s", ++initialize_count,
1051 _klass->name()->as_C_string());
1052
1053
1054 // Iterate through all interfaces
1055 int i;
1056 for(i = 0; i < num_interfaces; i++) {
1057 itableOffsetEntry* ioe = offset_entry(i);
1058 assert(bounds_check_offset(ioe), "");
1059 HandleMark hm(THREAD);
1060 KlassHandle interf_h (THREAD, ioe->interface_klass());
1061 assert(interf_h() != NULL && ioe->offset() != 0, "bad offset entry in itable");
1062 if (_klass == interf_h && !_klass->has_self_itable()) {
1063 // close off this itable early
1064 assert(i == num_interfaces -1, "self-itable must be last");
1065 ioe->initialize(NULL, 0);
1066 break;
1067 }
1068 initialize_itable_for_interface(ioe->offset(), interf_h, checkconstraints, CHECK);
1069 }
1070
1071 }
1072 // Check that the last entry is empty
1073 itableOffsetEntry* ioe = offset_entry(size_offset_table() - 1);
1074 assert(bounds_check_offset(ioe), "");
1075 guarantee((intptr_t*)(ioe+1) <= _klass->end_of_itable(), "oob");
1076 guarantee(ioe->interface_klass() == NULL && ioe->offset() == 0, "terminator entry missing");
1077 }
1078
1079
1080 inline bool interface_method_needs_itable_index(Method* m) {
1081 if (m->is_static()) return false; // e.g., Stream.empty
1082 if (m->is_initializer()) return false; // <init> or <clinit>
1083 // If an interface redeclares a method from java.lang.Object,
1084 // it should already have a vtable index, don't touch it.
1085 // e.g., CharSequence.toString (from initialize_vtable)
1086 // if (m->has_vtable_index()) return false; // NO!
1087 return true;
1088 }
1089
1090 int klassItable::assign_itable_indices_for_interface(Klass* klass) {
1091 // an interface does not have an itable, but its methods need to be numbered
1092 log_develop_debug(itables)("%3d: Initializing itable indices for interface %s",
1093 ++initialize_count, klass->name()->as_C_string());
1094 Array<Method*>* methods = InstanceKlass::cast(klass)->methods();
1095 int nof_methods = methods->length();
1096 int ime_num = 0;
1097 for (int i = 0; i < nof_methods; i++) {
1098 Method* m = methods->at(i);
1099 if (interface_method_needs_itable_index(m)) {
1100 assert(!m->is_final_method(), "no final interface methods");
1101 // If m is already assigned a vtable index, do not disturb it.
1102 if (log_develop_is_enabled(Trace, itables)) {
1103 ResourceMark rm;
1104 outputStream* logst = LogHandle(itables)::trace_stream();
1105 assert(m != NULL, "methods can never be null");
1106 const char* sig = m->name_and_sig_as_C_string();
1107 if (m->has_vtable_index()) {
1108 logst->print("vtable index %d for method: %s, flags: ", m->vtable_index(), sig);
1109 } else {
1110 logst->print("itable index %d for method: %s, flags: ", ime_num, sig);
1111 }
1112 m->print_linkage_flags(logst);
1113 logst->cr();
1114 }
1115 if (!m->has_vtable_index()) {
1116 assert(m->vtable_index() == Method::pending_itable_index, "set by initialize_vtable");
1117 m->set_itable_index(ime_num);
1118 // Progress to next itable entry
1119 ime_num++;
1120 }
1121 }
1122 }
1123 assert(ime_num == method_count_for_interface(klass), "proper sizing");
1124 return ime_num;
1125 }
1126
1127 int klassItable::method_count_for_interface(Klass* interf) {
1128 assert(interf->is_instance_klass(), "must be");
1129 assert(interf->is_interface(), "must be");
1130 Array<Method*>* methods = InstanceKlass::cast(interf)->methods();
1131 int nof_methods = methods->length();
1132 int length = 0;
1133 while (nof_methods > 0) {
1134 Method* m = methods->at(nof_methods-1);
1135 if (m->has_itable_index()) {
1136 length = m->itable_index() + 1;
1137 break;
1138 }
1139 nof_methods -= 1;
1140 }
1141 #ifdef ASSERT
1142 int nof_methods_copy = nof_methods;
1143 while (nof_methods_copy > 0) {
1144 Method* mm = methods->at(--nof_methods_copy);
1145 assert(!mm->has_itable_index() || mm->itable_index() < length, "");
1146 }
1147 #endif //ASSERT
1148 // return the rightmost itable index, plus one; or 0 if no methods have
1149 // itable indices
1150 return length;
1151 }
1152
1153
1154 void klassItable::initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS) {
1155 Array<Method*>* methods = InstanceKlass::cast(interf_h())->methods();
1156 int nof_methods = methods->length();
1157 HandleMark hm;
1158 assert(nof_methods > 0 || interf_h() == SystemDictionary::Cloneable_klass(),
1159 "at least one method must exist for interface to be in vtable");
1160 Handle interface_loader (THREAD, InstanceKlass::cast(interf_h())->class_loader());
1161
1162 assert(_klass() != interf_h() || _klass->has_self_itable(),
1163 "self references are carefully marked");
1164
1165 int ime_count = method_count_for_interface(interf_h());
1166 for (int i = 0; i < nof_methods; i++) {
1167 Method* m = methods->at(i);
1168 methodHandle target;
1169 if (m->has_itable_index()) {
1170 // This search must match the runtime resolution, i.e. selection search for invokeinterface
1171 // to correctly enforce loader constraints for interface method inheritance
1172 target = LinkResolver::lookup_instance_method_in_klasses(_klass, m->name(), m->signature(), CHECK);
1173 }
1174 if (target == NULL || !target->is_public() || target->is_abstract()) {
1175 // Entry does not resolve. Leave it empty for AbstractMethodError.
1176 if (!(target == NULL) && !target->is_public()) {
1177 // Stuff an IllegalAccessError throwing method in there instead.
1178 itableOffsetEntry::method_entry(_klass(), method_table_offset)[m->itable_index()].
1179 initialize(Universe::throw_illegal_access_error());
1180 }
1181 } else {
1182 // Entry did resolve, check loader constraints before initializing
1183 // if checkconstraints requested
1184 if (checkconstraints) {
1185 Handle method_holder_loader (THREAD, target->method_holder()->class_loader());
1186 if (method_holder_loader() != interface_loader()) {
1187 ResourceMark rm(THREAD);
1188 Symbol* failed_type_symbol =
1189 SystemDictionary::check_signature_loaders(m->signature(),
1190 method_holder_loader,
1191 interface_loader,
1192 true, CHECK);
1193 if (failed_type_symbol != NULL) {
1194 const char* msg = "loader constraint violation in interface "
1195 "itable initialization: when resolving method \"%s\" the class"
1196 " loader (instance of %s) of the current class, %s, "
1197 "and the class loader (instance of %s) for interface "
1198 "%s have different Class objects for the type %s "
1199 "used in the signature";
1200 char* sig = target()->name_and_sig_as_C_string();
1201 const char* loader1 = SystemDictionary::loader_name(method_holder_loader());
1202 char* current = _klass->name()->as_C_string();
1203 const char* loader2 = SystemDictionary::loader_name(interface_loader());
1204 char* iface = InstanceKlass::cast(interf_h())->name()->as_C_string();
1205 char* failed_type_name = failed_type_symbol->as_C_string();
1206 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
1207 strlen(current) + strlen(loader2) + strlen(iface) +
1208 strlen(failed_type_name);
1209 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
1210 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2,
1211 iface, failed_type_name);
1212 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
1213 }
1214 }
1215 }
1216
1217 // ime may have moved during GC so recalculate address
1218 int ime_num = m->itable_index();
1219 assert(ime_num < ime_count, "oob");
1220 assert(bounds_check_method(&itableOffsetEntry::method_entry(_klass(), method_table_offset)[ime_num]), "");
1221 itableOffsetEntry::method_entry(_klass(), method_table_offset)[ime_num].initialize(target());
1222 if (log_develop_is_enabled(Trace, itables)) {
1223 ResourceMark rm(THREAD);
1224 if (target() != NULL) {
1225 outputStream* logst = LogHandle(itables)::trace_stream();
1226 char* sig = target()->name_and_sig_as_C_string();
1227 logst->print("interface: %s, ime_num: %d, target: %s, method_holder: %s ",
1228 interf_h()->internal_name(), ime_num, sig,
1229 target()->method_holder()->internal_name());
1230 logst->print("target_method flags: ");
1231 target()->print_linkage_flags(logst);
1232 logst->cr();
1233 }
1234 }
1235 }
1236 }
1237 }
1238
1239 // Update entry for specific Method*
1240 void klassItable::initialize_with_method(Method* m) {
1241 itableMethodEntry* ime = method_entry(0);
1242 assert(bounds_check_method(ime), "");
1243 for(int i = 0; i < _size_method_table; i++) {
1244 if (ime->method() == m) {
1245 assert(bounds_check_method(ime), "");
1246 ime->initialize(m);
1247 }
1248 ime++;
1249 }
1250 }
1251
1252 #if INCLUDE_JVMTI
1253 // search the itable for uses of either obsolete or EMCP methods
1254 void klassItable::adjust_method_entries(InstanceKlass* holder, bool * trace_name_printed) {
1255
1256 itableMethodEntry* ime = method_entry(0);
1257 for (int i = 0; i < _size_method_table; i++, ime++) {
1258 assert(bounds_check_method(ime), "");
1259 Method* old_method = ime->method();
1260 if (old_method == NULL || old_method->method_holder() != holder || !old_method->is_old()) {
1261 continue; // skip uninteresting entries
1262 }
1263 assert(!old_method->is_deleted(), "itable methods may not be deleted");
1264
1265 Method* new_method = holder->method_with_idnum(old_method->orig_method_idnum());
1266
1267 assert(new_method != NULL, "method_with_idnum() should not be NULL");
1268 assert(old_method != new_method, "sanity check");
1269
1270 ime->initialize(new_method);
1271
1272 if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
1273 if (!(*trace_name_printed)) {
1274 // RC_TRACE_MESG macro has an embedded ResourceMark
1275 RC_TRACE_MESG(("adjust: name=%s",
1276 old_method->method_holder()->external_name()));
1277 *trace_name_printed = true;
1278 }
1279 // RC_TRACE macro has an embedded ResourceMark
1280 RC_TRACE(0x00200000, ("itable method update: %s(%s)",
1281 new_method->name()->as_C_string(),
1282 new_method->signature()->as_C_string()));
1283 }
1284 }
1285 }
1286
1287 // an itable should never contain old or obsolete methods
1288 bool klassItable::check_no_old_or_obsolete_entries() {
1289 itableMethodEntry* ime = method_entry(0);
1290 for (int i = 0; i < _size_method_table; i++) {
1291 assert(bounds_check_method(ime), "");
1292 Method* m = ime->method();
1293 if (m != NULL &&
1294 (NOT_PRODUCT(!m->is_valid() ||) m->is_old() || m->is_obsolete())) {
1295 return false;
1296 }
1297 ime++;
1298 }
1299 return true;
1300 }
1301
1302 void klassItable::dump_itable() {
1303 itableMethodEntry* ime = method_entry(0);
1304 tty->print_cr("itable dump --");
1305 for (int i = 0; i < _size_method_table; i++) {
1306 Method* m = ime->method();
1307 if (m != NULL) {
1308 tty->print(" (%5d) ", i);
1309 m->access_flags().print_on(tty);
1310 if (m->is_default_method()) {
1311 tty->print("default ");
1312 }
1313 tty->print(" -- ");
1314 m->print_name(tty);
1315 tty->cr();
1316 }
1317 ime++;
1318 }
1319 }
1320 #endif // INCLUDE_JVMTI
1321
1322
1323 // Setup
1324 class InterfaceVisiterClosure : public StackObj {
1325 public:
1326 virtual void doit(Klass* intf, int method_count) = 0;
1327 };
1328
1329 int count_interface_methods_needing_itable_index(Array<Method*>* methods) {
1330 int method_count = 0;
1331 if (methods->length() > 0) {
1332 for (int i = methods->length(); --i >= 0; ) {
1333 if (interface_method_needs_itable_index(methods->at(i))) {
1334 method_count++;
1335 }
1336 }
1337 }
1338 return method_count;
1339 }
1340
1341 // Visit all interfaces with at least one itable method
1342 void visit_all_interfaces(Array<Klass*>* transitive_intf, InterfaceVisiterClosure *blk) {
1343 // Handle array argument
1344 for(int i = 0; i < transitive_intf->length(); i++) {
1345 Klass* intf = transitive_intf->at(i);
1346 assert(intf->is_interface(), "sanity check");
1347
1348 // Find no. of itable methods
1349 Array<Method*>* methods = InstanceKlass::cast(intf)->methods();
1350 int method_count = count_interface_methods_needing_itable_index(methods);
1351 // similar to: method_count = klassItable::method_count_for_interface(intf);
1352
1353 // Only count interfaces with at least one method
1354 if (method_count > 0) {
1355 blk->doit(intf, method_count);
1356 }
1357 }
1358 }
1359
1360 class CountInterfacesClosure : public InterfaceVisiterClosure {
1361 private:
1362 int _nof_methods;
1363 int _nof_interfaces;
1364 public:
1365 CountInterfacesClosure() { _nof_methods = 0; _nof_interfaces = 0; }
1366
1367 int nof_methods() const { return _nof_methods; }
1368 int nof_interfaces() const { return _nof_interfaces; }
1369
1370 void doit(Klass* intf, int method_count) { _nof_methods += method_count; _nof_interfaces++; }
1371 };
1372
1373 class SetupItableClosure : public InterfaceVisiterClosure {
1374 private:
1375 itableOffsetEntry* _offset_entry;
1376 itableMethodEntry* _method_entry;
1377 address _klass_begin;
1378 public:
1379 SetupItableClosure(address klass_begin,
1380 itableOffsetEntry* offset_entry,
1381 itableMethodEntry* method_entry) {
1382 _klass_begin = klass_begin;
1383 _offset_entry = offset_entry;
1384 _method_entry = method_entry;
1385 }
1386
1387 itableOffsetEntry* offset_entry() const { return _offset_entry; }
1388 itableMethodEntry* method_entry() const { return _method_entry; }
1389
1390 void doit(Klass* intf, int method_count) {
1391 int offset = ((address)_method_entry) - _klass_begin;
1392 _offset_entry->initialize(intf, offset);
1393 _offset_entry++;
1394 _method_entry += method_count;
1395 }
1396 };
1397
1398 int klassItable::compute_itable_size(AccessFlags class_flags,
1399 Array<Method*>* methods,
1400 Array<Klass*>* transitive_interfaces,
1401 bool *has_self_itable_result) {
1402 int self_itable_length = 0;
1403 if (class_flags.is_interface()) {
1404 // Compute an itable for interfaces if caller requests it.
1405 // This allows the interface to be used as an "extra super" holding behavior.
1406 assert(EnableExtraSuper, "");
1407 // Add interfaces for myself to the end of the itable.
1408 self_itable_length = count_interface_methods_needing_itable_index(methods);
1409 if (self_itable_length != 0)
1410 (*has_self_itable_result) = true;
1411 }
1412
1413 // Count no of interfaces and total number of interface methods
1414 CountInterfacesClosure cic;
1415 visit_all_interfaces(transitive_interfaces, &cic);
1416 if (self_itable_length != 0)
1417 cic.doit(NULL, self_itable_length);
1418
1419 // There's alway an extra itable entry so we can null-terminate it.
1420 int itable_size = calc_itable_size(cic.nof_interfaces() + 1, cic.nof_methods());
1421
1422 // Statistics
1423 update_stats(itable_size * wordSize);
1424
1425 return itable_size;
1426 }
1427
1428
1429 // Fill out offset table and interface klasses into the itable space
1430 void klassItable::setup_itable_offset_table(instanceKlassHandle klass) {
1431 if (!klass->has_itable_entries()) {
1432 assert(klass->itable_length() == 0 ||
1433 ((itableOffsetEntry*)klass->start_of_itable())->interface_klass() == NULL,
1434 "proper termination");
1435 return;
1436 }
1437 assert(!klass->is_interface() || EnableExtraSuper, "Should have zero length itable");
1438 int self_itable_length = 0;
1439 if (klass->is_interface() && klass->has_self_itable()) {
1440 self_itable_length = count_interface_methods_needing_itable_index(klass->methods());
1441 }
1442
1443 // Count no of interfaces and total number of interface methods
1444 CountInterfacesClosure cic;
1445 visit_all_interfaces(klass->transitive_interfaces(), &cic);
1446 if (self_itable_length != 0)
1447 cic.doit(klass(), self_itable_length);
1448
1449 int nof_methods = cic.nof_methods();
1450 int nof_interfaces = cic.nof_interfaces();
1451
1452 // Add one extra entry so we can null-terminate the table
1453 nof_interfaces++;
1454
1455 DEBUG_ONLY(bool want_self_itable = false);
1456 assert(compute_itable_size(klass->access_flags(),
1457 klass->methods(),
1458 klass->transitive_interfaces(),
1459 &want_self_itable) ==
1460 calc_itable_size(nof_interfaces, nof_methods),
1461 "mismatch calculation of itable size");
1462
1463 // Fill-out offset table
1464 itableOffsetEntry* ioe = (itableOffsetEntry*)klass->start_of_itable();
1465 itableMethodEntry* ime = (itableMethodEntry*)(ioe + nof_interfaces);
1466 intptr_t* end = klass->end_of_itable();
1467 assert(klass->itable_length() == itableOffsetEntry::size() || klass->itable()->bounds_check_offset(ioe), "");
1468 assert((oop*)ime > (oop*)klass(), "wrong offset calculation (0)");
1469 assert((oop*)(ime + nof_methods) <= (oop*)klass->start_of_nonstatic_oop_maps(), "wrong offset calculation (1)");
1470 assert((oop*)(end) >= (oop*)(ime + nof_methods), "wrong offset calculation (2)");
1471
1472 // Visit all interfaces and initialize itable offset table
1473 SetupItableClosure sic((address)klass(), ioe, ime);
1474 visit_all_interfaces(klass->transitive_interfaces(), &sic);
1475 if (self_itable_length != 0) {
1476 guarantee((intptr_t*)(sic.method_entry() + self_itable_length) <= klass->end_of_itable(),
1477 "self-itable must not overflow klass");
1478 sic.doit(klass(), self_itable_length);
1479 }
1480 guarantee((intptr_t*)sic.method_entry() <= klass->end_of_itable(),
1481 "itable must not overflow klass");
1482 guarantee(sic.offset_entry()->interface_klass() == NULL, "proper termination");
1483
1484 #ifdef ASSERT
1485 klassItable* itable = klass->itable();
1486 assert(klass->itable_length() == itableOffsetEntry::size() || itable->bounds_check_offset(ioe), "");
1487 assert(klass->itable_length() == itableOffsetEntry::size() || itable->bounds_check_method(ime), "");
1488 ioe = sic.offset_entry();
1489 ime = sic.method_entry();
1490 if (klass->itable_length() != itableOffsetEntry::size()) {
1491 assert(itable->bounds_check_offset(ioe-1), "");
1492 assert(itable->bounds_check_method(ime-1), "");
1493 }
1494 oop* v = (oop*) klass->end_of_itable();
1495 assert( (oop*)(ime) == v, "wrong offset calculation (2)");
1496 #endif
1497 }
1498
1499
1500 // inverse to itable_index
1501 Method* klassItable::method_for_itable_index(Klass* intf, int itable_index) {
1502 assert(InstanceKlass::cast(intf)->is_interface(), "sanity check");
1503 assert(intf->verify_itable_index(itable_index), "");
1504 Array<Method*>* methods = InstanceKlass::cast(intf)->methods();
1505
1506 if (itable_index < 0 || itable_index >= method_count_for_interface(intf))
1507 return NULL; // help caller defend against bad indices
1508
1509 int index = itable_index;
1510 Method* m = methods->at(index);
1511 int index2 = -1;
1512 while (!m->has_itable_index() ||
1513 (index2 = m->itable_index()) != itable_index) {
1514 assert(index2 < itable_index, "monotonic");
1515 if (++index == methods->length())
1516 return NULL;
1517 m = methods->at(index);
1518 }
1519 assert(m->itable_index() == itable_index, "correct inverse");
1520
1521 return m;
1522 }
1523
1524 void klassVtable::verify(outputStream* st, bool forced) {
1525 // make sure table is initialized
1526 if (!Universe::is_fully_initialized()) return;
1527 #ifndef PRODUCT
1528 // avoid redundant verifies
1529 if (!forced && _verify_count == Universe::verify_count()) return;
1530 _verify_count = Universe::verify_count();
1531 #endif
1532 oop* end_of_obj = (oop*)_klass() + _klass()->size();
1533 oop* end_of_vtable = (oop *)&table()[_length];
1534 if (end_of_vtable > end_of_obj) {
1535 fatal("klass %s: klass object too short (vtable extends beyond end)",
1536 _klass->internal_name());
1537 }
1538
1539 for (int i = 0; i < _length; i++) table()[i].verify(this, st);
1540 // verify consistency with superKlass vtable
1541 Klass* super = _klass->super();
1542 if (super != NULL) {
1543 InstanceKlass* sk = InstanceKlass::cast(super);
1544 klassVtable* vt = sk->vtable();
1545 for (int i = 0; i < vt->length(); i++) {
1546 verify_against(st, vt, i);
1547 }
1548 }
1549 }
1550
1551 void klassVtable::verify_against(outputStream* st, klassVtable* vt, int index) {
1552 vtableEntry* vte = &vt->table()[index];
1553 if (vte->method()->name() != table()[index].method()->name() ||
1554 vte->method()->signature() != table()[index].method()->signature()) {
1555 fatal("mismatched name/signature of vtable entries");
1556 }
1557 }
1558
1559 #ifndef PRODUCT
1560 void klassVtable::print() {
1561 ResourceMark rm;
1562 tty->print("klassVtable for klass %s (length %d):\n", _klass->internal_name(), length());
1563 for (int i = 0; i < length(); i++) {
1564 table()[i].print();
1565 tty->cr();
1566 }
1567 }
1568 #endif
1569
1570 void vtableEntry::verify(klassVtable* vt, outputStream* st) {
1571 NOT_PRODUCT(FlagSetting fs(IgnoreLockingAssertions, true));
1572 assert(method() != NULL, "must have set method");
1573 method()->verify();
1574 // we sub_type, because it could be a miranda method
1575 if (!vt->klass()->is_subtype_of(method()->method_holder())) {
1576 #ifndef PRODUCT
1577 print();
1578 #endif
1579 fatal("vtableEntry " PTR_FORMAT ": method is from subclass", p2i(this));
1580 }
1581 }
1582
1583 #ifndef PRODUCT
1584
1585 void vtableEntry::print() {
1586 ResourceMark rm;
1587 tty->print("vtableEntry %s: ", method()->name()->as_C_string());
1588 if (Verbose) {
1589 tty->print("m " PTR_FORMAT " ", p2i(method()));
1590 }
1591 }
1592
1593 class VtableStats : AllStatic {
1594 public:
1595 static int no_klasses; // # classes with vtables
1596 static int no_array_klasses; // # array classes
1597 static int no_instance_klasses; // # instanceKlasses
1598 static int sum_of_vtable_len; // total # of vtable entries
1599 static int sum_of_array_vtable_len; // total # of vtable entries in array klasses only
1600 static int fixed; // total fixed overhead in bytes
1601 static int filler; // overhead caused by filler bytes
1602 static int entries; // total bytes consumed by vtable entries
1603 static int array_entries; // total bytes consumed by array vtable entries
1604
1605 static void do_class(Klass* k) {
1606 Klass* kl = k;
1607 klassVtable* vt = kl->vtable();
1608 if (vt == NULL) return;
1609 no_klasses++;
1610 if (kl->is_instance_klass()) {
1611 no_instance_klasses++;
1612 kl->array_klasses_do(do_class);
1613 }
1614 if (kl->is_array_klass()) {
1615 no_array_klasses++;
1616 sum_of_array_vtable_len += vt->length();
1617 }
1618 sum_of_vtable_len += vt->length();
1619 }
1620
1621 static void compute() {
1622 SystemDictionary::classes_do(do_class);
1623 fixed = no_klasses * oopSize; // vtable length
1624 // filler size is a conservative approximation
1625 filler = oopSize * (no_klasses - no_instance_klasses) * (sizeof(InstanceKlass) - sizeof(ArrayKlass) - 1);
1626 entries = sizeof(vtableEntry) * sum_of_vtable_len;
1627 array_entries = sizeof(vtableEntry) * sum_of_array_vtable_len;
1628 }
1629 };
1630
1631 int VtableStats::no_klasses = 0;
1632 int VtableStats::no_array_klasses = 0;
1633 int VtableStats::no_instance_klasses = 0;
1634 int VtableStats::sum_of_vtable_len = 0;
1635 int VtableStats::sum_of_array_vtable_len = 0;
1636 int VtableStats::fixed = 0;
1637 int VtableStats::filler = 0;
1638 int VtableStats::entries = 0;
1639 int VtableStats::array_entries = 0;
1640
1641 void klassVtable::print_statistics() {
1642 ResourceMark rm;
1643 HandleMark hm;
1644 VtableStats::compute();
1645 tty->print_cr("vtable statistics:");
1646 tty->print_cr("%6d classes (%d instance, %d array)", VtableStats::no_klasses, VtableStats::no_instance_klasses, VtableStats::no_array_klasses);
1647 int total = VtableStats::fixed + VtableStats::filler + VtableStats::entries;
1648 tty->print_cr("%6d bytes fixed overhead (refs + vtable object header)", VtableStats::fixed);
1649 tty->print_cr("%6d bytes filler overhead", VtableStats::filler);
1650 tty->print_cr("%6d bytes for vtable entries (%d for arrays)", VtableStats::entries, VtableStats::array_entries);
1651 tty->print_cr("%6d bytes total", total);
1652 }
1653
1654 int klassItable::_total_classes; // Total no. of classes with itables
1655 long klassItable::_total_size; // Total no. of bytes used for itables
1656
1657 void klassItable::print_statistics() {
1658 tty->print_cr("itable statistics:");
1659 tty->print_cr("%6d classes with itables", _total_classes);
1660 tty->print_cr("%6lu K uses for itables (average by class: %ld bytes)", _total_size / K, _total_size / _total_classes);
1661 }
1662
1663 #endif // PRODUCT