Tue, 19 Nov 2013 11:53:58 -0800
8028514: PPC64: Fix C++ Interpreter after '7195622: CheckUnhandledOops has limited usefulness now'
Summary: fix CPP-interpreter after CheckUnhandledOops was re-enabled in the fastdebug build
Reviewed-by: kvn, dholmes, lfoltan
1 /*
2 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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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.
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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, and none of C's superclasses implements I.
53 // Let's say there is an abstract method m in I that neither C
54 // nor any of its super classes implement (i.e there is no method of any access,
55 // with the same name and signature as m), then m is a Miranda method which is
56 // entered as a public abstract method in C's vtable. From then on it should
57 // treated as any other public method in C for method over-ride purposes.
58 void klassVtable::compute_vtable_size_and_num_mirandas(
59 int* vtable_length_ret, int* num_new_mirandas,
60 GrowableArray<Method*>* all_mirandas, Klass* super,
61 Array<Method*>* methods, AccessFlags class_flags,
62 Handle classloader, Symbol* classname, Array<Klass*>* local_interfaces,
63 TRAPS) {
64 No_Safepoint_Verifier nsv;
66 // set up default result values
67 int vtable_length = 0;
69 // start off with super's vtable length
70 InstanceKlass* sk = (InstanceKlass*)super;
71 vtable_length = super == NULL ? 0 : sk->vtable_length();
73 // go thru each method in the methods table to see if it needs a new entry
74 int len = methods->length();
75 for (int i = 0; i < len; i++) {
76 assert(methods->at(i)->is_method(), "must be a Method*");
77 methodHandle mh(THREAD, methods->at(i));
79 if (needs_new_vtable_entry(mh, super, classloader, classname, class_flags, THREAD)) {
80 vtable_length += vtableEntry::size(); // we need a new entry
81 }
82 }
84 GrowableArray<Method*> new_mirandas(20);
85 // compute the number of mirandas methods that must be added to the end
86 get_mirandas(&new_mirandas, all_mirandas, super, methods, NULL, local_interfaces);
87 *num_new_mirandas = new_mirandas.length();
89 vtable_length += *num_new_mirandas * vtableEntry::size();
91 if (Universe::is_bootstrapping() && vtable_length == 0) {
92 // array classes don't have their superclass set correctly during
93 // bootstrapping
94 vtable_length = Universe::base_vtable_size();
95 }
97 if (super == NULL && !Universe::is_bootstrapping() &&
98 vtable_length != Universe::base_vtable_size()) {
99 // Someone is attempting to redefine java.lang.Object incorrectly. The
100 // only way this should happen is from
101 // SystemDictionary::resolve_from_stream(), which will detect this later
102 // and throw a security exception. So don't assert here to let
103 // the exception occur.
104 vtable_length = Universe::base_vtable_size();
105 }
106 assert(super != NULL || vtable_length == Universe::base_vtable_size(),
107 "bad vtable size for class Object");
108 assert(vtable_length % vtableEntry::size() == 0, "bad vtable length");
109 assert(vtable_length >= Universe::base_vtable_size(), "vtable too small");
111 *vtable_length_ret = vtable_length;
112 }
114 int klassVtable::index_of(Method* m, int len) const {
115 assert(m->has_vtable_index(), "do not ask this of non-vtable methods");
116 return m->vtable_index();
117 }
119 // Copy super class's vtable to the first part (prefix) of this class's vtable,
120 // and return the number of entries copied. Expects that 'super' is the Java
121 // super class (arrays can have "array" super classes that must be skipped).
122 int klassVtable::initialize_from_super(KlassHandle super) {
123 if (super.is_null()) {
124 return 0;
125 } else {
126 // copy methods from superKlass
127 // can't inherit from array class, so must be InstanceKlass
128 assert(super->oop_is_instance(), "must be instance klass");
129 InstanceKlass* sk = (InstanceKlass*)super();
130 klassVtable* superVtable = sk->vtable();
131 assert(superVtable->length() <= _length, "vtable too short");
132 #ifdef ASSERT
133 superVtable->verify(tty, true);
134 #endif
135 superVtable->copy_vtable_to(table());
136 #ifndef PRODUCT
137 if (PrintVtables && Verbose) {
138 ResourceMark rm;
139 tty->print_cr("copy vtable from %s to %s size %d", sk->internal_name(), klass()->internal_name(), _length);
140 }
141 #endif
142 return superVtable->length();
143 }
144 }
146 //
147 // Revised lookup semantics introduced 1.3 (Kestrel beta)
148 void klassVtable::initialize_vtable(bool checkconstraints, TRAPS) {
150 // Note: Arrays can have intermediate array supers. Use java_super to skip them.
151 KlassHandle super (THREAD, klass()->java_super());
152 int nofNewEntries = 0;
154 if (PrintVtables && !klass()->oop_is_array()) {
155 ResourceMark rm(THREAD);
156 tty->print_cr("Initializing: %s", _klass->name()->as_C_string());
157 }
159 #ifdef ASSERT
160 oop* end_of_obj = (oop*)_klass() + _klass()->size();
161 oop* end_of_vtable = (oop*)&table()[_length];
162 assert(end_of_vtable <= end_of_obj, "vtable extends beyond end");
163 #endif
165 if (Universe::is_bootstrapping()) {
166 // just clear everything
167 for (int i = 0; i < _length; i++) table()[i].clear();
168 return;
169 }
171 int super_vtable_len = initialize_from_super(super);
172 if (klass()->oop_is_array()) {
173 assert(super_vtable_len == _length, "arrays shouldn't introduce new methods");
174 } else {
175 assert(_klass->oop_is_instance(), "must be InstanceKlass");
177 Array<Method*>* methods = ik()->methods();
178 int len = methods->length();
179 int initialized = super_vtable_len;
181 // Check each of this class's methods against super;
182 // if override, replace in copy of super vtable, otherwise append to end
183 for (int i = 0; i < len; i++) {
184 // update_inherited_vtable can stop for gc - ensure using handles
185 HandleMark hm(THREAD);
186 assert(methods->at(i)->is_method(), "must be a Method*");
187 methodHandle mh(THREAD, methods->at(i));
189 bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, -1, checkconstraints, CHECK);
191 if (needs_new_entry) {
192 put_method_at(mh(), initialized);
193 mh()->set_vtable_index(initialized); // set primary vtable index
194 initialized++;
195 }
196 }
198 // update vtable with default_methods
199 Array<Method*>* default_methods = ik()->default_methods();
200 if (default_methods != NULL) {
201 len = default_methods->length();
202 if (len > 0) {
203 Array<int>* def_vtable_indices = NULL;
204 if ((def_vtable_indices = ik()->default_vtable_indices()) == NULL) {
205 def_vtable_indices = ik()->create_new_default_vtable_indices(len, CHECK);
206 } else {
207 assert(def_vtable_indices->length() == len, "reinit vtable len?");
208 }
209 for (int i = 0; i < len; i++) {
210 HandleMark hm(THREAD);
211 assert(default_methods->at(i)->is_method(), "must be a Method*");
212 methodHandle mh(THREAD, default_methods->at(i));
214 bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, i, checkconstraints, CHECK);
216 // needs new entry
217 if (needs_new_entry) {
218 put_method_at(mh(), initialized);
219 def_vtable_indices->at_put(i, initialized); //set vtable index
220 initialized++;
221 }
222 }
223 }
224 }
226 // add miranda methods; it will also return the updated initialized
227 initialized = fill_in_mirandas(initialized);
229 // In class hierarchies where the accessibility is not increasing (i.e., going from private ->
230 // package_private -> public/protected), the vtable might actually be smaller than our initial
231 // calculation.
232 assert(initialized <= _length, "vtable initialization failed");
233 for(;initialized < _length; initialized++) {
234 put_method_at(NULL, initialized);
235 }
236 NOT_PRODUCT(verify(tty, true));
237 }
238 }
240 // Called for cases where a method does not override its superclass' vtable entry
241 // For bytecodes not produced by javac together it is possible that a method does not override
242 // the superclass's method, but might indirectly override a super-super class's vtable entry
243 // If none found, return a null superk, else return the superk of the method this does override
244 InstanceKlass* klassVtable::find_transitive_override(InstanceKlass* initialsuper, methodHandle target_method,
245 int vtable_index, Handle target_loader, Symbol* target_classname, Thread * THREAD) {
246 InstanceKlass* superk = initialsuper;
247 while (superk != NULL && superk->super() != NULL) {
248 InstanceKlass* supersuperklass = InstanceKlass::cast(superk->super());
249 klassVtable* ssVtable = supersuperklass->vtable();
250 if (vtable_index < ssVtable->length()) {
251 Method* super_method = ssVtable->method_at(vtable_index);
252 #ifndef PRODUCT
253 Symbol* name= target_method()->name();
254 Symbol* signature = target_method()->signature();
255 assert(super_method->name() == name && super_method->signature() == signature, "vtable entry name/sig mismatch");
256 #endif
257 if (supersuperklass->is_override(super_method, target_loader, target_classname, THREAD)) {
258 #ifndef PRODUCT
259 if (PrintVtables && Verbose) {
260 ResourceMark rm(THREAD);
261 char* sig = target_method()->name_and_sig_as_C_string();
262 tty->print("transitive overriding superclass %s with %s::%s index %d, original flags: ",
263 supersuperklass->internal_name(),
264 _klass->internal_name(), sig, vtable_index);
265 super_method->access_flags().print_on(tty);
266 if (super_method->is_default_method()) {
267 tty->print("default");
268 }
269 tty->print("overriders flags: ");
270 target_method->access_flags().print_on(tty);
271 if (target_method->is_default_method()) {
272 tty->print("default");
273 }
274 }
275 #endif /*PRODUCT*/
276 break; // return found superk
277 }
278 } else {
279 // super class has no vtable entry here, stop transitive search
280 superk = (InstanceKlass*)NULL;
281 break;
282 }
283 // if no override found yet, continue to search up
284 superk = InstanceKlass::cast(superk->super());
285 }
287 return superk;
288 }
290 // Update child's copy of super vtable for overrides
291 // OR return true if a new vtable entry is required.
292 // Only called for InstanceKlass's, i.e. not for arrays
293 // If that changed, could not use _klass as handle for klass
294 bool klassVtable::update_inherited_vtable(InstanceKlass* klass, methodHandle target_method,
295 int super_vtable_len, int default_index,
296 bool checkconstraints, TRAPS) {
297 ResourceMark rm;
298 bool allocate_new = true;
299 assert(klass->oop_is_instance(), "must be InstanceKlass");
301 Array<int>* def_vtable_indices = NULL;
302 bool is_default = false;
303 // default methods are concrete methods in superinterfaces which are added to the vtable
304 // with their real method_holder
305 // Since vtable and itable indices share the same storage, don't touch
306 // the default method's real vtable/itable index
307 // default_vtable_indices stores the vtable value relative to this inheritor
308 if (default_index >= 0 ) {
309 is_default = true;
310 def_vtable_indices = klass->default_vtable_indices();
311 assert(def_vtable_indices != NULL, "def vtable alloc?");
312 assert(default_index <= def_vtable_indices->length(), "def vtable len?");
313 } else {
314 assert(klass == target_method()->method_holder(), "caller resp.");
315 // Initialize the method's vtable index to "nonvirtual".
316 // If we allocate a vtable entry, we will update it to a non-negative number.
317 target_method()->set_vtable_index(Method::nonvirtual_vtable_index);
318 }
320 // Static and <init> methods are never in
321 if (target_method()->is_static() || target_method()->name() == vmSymbols::object_initializer_name()) {
322 return false;
323 }
325 if (target_method->is_final_method(klass->access_flags())) {
326 // a final method never needs a new entry; final methods can be statically
327 // resolved and they have to be present in the vtable only if they override
328 // a super's method, in which case they re-use its entry
329 allocate_new = false;
330 } else if (klass->is_interface()) {
331 allocate_new = false; // see note below in needs_new_vtable_entry
332 // An interface never allocates new vtable slots, only inherits old ones.
333 // This method will either be assigned its own itable index later,
334 // or be assigned an inherited vtable index in the loop below.
335 // default methods store their vtable indices in the inheritors default_vtable_indices
336 assert (default_index == -1, "interfaces don't store resolved default methods");
337 target_method()->set_vtable_index(Method::pending_itable_index);
338 }
340 // we need a new entry if there is no superclass
341 if (klass->super() == NULL) {
342 return allocate_new;
343 }
345 // private methods in classes always have a new entry in the vtable
346 // specification interpretation since classic has
347 // private methods not overriding
348 // JDK8 adds private methods in interfaces which require invokespecial
349 if (target_method()->is_private()) {
350 return allocate_new;
351 }
353 // search through the vtable and update overridden entries
354 // Since check_signature_loaders acquires SystemDictionary_lock
355 // which can block for gc, once we are in this loop, use handles
356 // For classfiles built with >= jdk7, we now look for transitive overrides
358 Symbol* name = target_method()->name();
359 Symbol* signature = target_method()->signature();
361 KlassHandle target_klass(THREAD, target_method()->method_holder());
362 if (target_klass == NULL) {
363 target_klass = _klass;
364 }
366 Handle target_loader(THREAD, target_klass->class_loader());
368 Symbol* target_classname = target_klass->name();
369 for(int i = 0; i < super_vtable_len; i++) {
370 Method* super_method = method_at(i);
371 // Check if method name matches
372 if (super_method->name() == name && super_method->signature() == signature) {
374 // get super_klass for method_holder for the found method
375 InstanceKlass* super_klass = super_method->method_holder();
377 if (is_default
378 || ((super_klass->is_override(super_method, target_loader, target_classname, THREAD))
379 || ((klass->major_version() >= VTABLE_TRANSITIVE_OVERRIDE_VERSION)
380 && ((super_klass = find_transitive_override(super_klass,
381 target_method, i, target_loader,
382 target_classname, THREAD))
383 != (InstanceKlass*)NULL))))
384 {
385 // overriding, so no new entry
386 allocate_new = false;
388 if (checkconstraints) {
389 // Override vtable entry if passes loader constraint check
390 // if loader constraint checking requested
391 // No need to visit his super, since he and his super
392 // have already made any needed loader constraints.
393 // Since loader constraints are transitive, it is enough
394 // to link to the first super, and we get all the others.
395 Handle super_loader(THREAD, super_klass->class_loader());
397 if (target_loader() != super_loader()) {
398 ResourceMark rm(THREAD);
399 Symbol* failed_type_symbol =
400 SystemDictionary::check_signature_loaders(signature, target_loader,
401 super_loader, true,
402 CHECK_(false));
403 if (failed_type_symbol != NULL) {
404 const char* msg = "loader constraint violation: when resolving "
405 "overridden method \"%s\" the class loader (instance"
406 " of %s) of the current class, %s, and its superclass loader "
407 "(instance of %s), have different Class objects for the type "
408 "%s used in the signature";
409 char* sig = target_method()->name_and_sig_as_C_string();
410 const char* loader1 = SystemDictionary::loader_name(target_loader());
411 char* current = target_klass->name()->as_C_string();
412 const char* loader2 = SystemDictionary::loader_name(super_loader());
413 char* failed_type_name = failed_type_symbol->as_C_string();
414 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
415 strlen(current) + strlen(loader2) + strlen(failed_type_name);
416 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
417 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2,
418 failed_type_name);
419 THROW_MSG_(vmSymbols::java_lang_LinkageError(), buf, false);
420 }
421 }
422 }
424 put_method_at(target_method(), i);
425 if (!is_default) {
426 target_method()->set_vtable_index(i);
427 } else {
428 if (def_vtable_indices != NULL) {
429 def_vtable_indices->at_put(default_index, i);
430 }
431 assert(super_method->is_default_method() || super_method->is_overpass()
432 || super_method->is_abstract(), "default override error");
433 }
436 #ifndef PRODUCT
437 if (PrintVtables && Verbose) {
438 ResourceMark rm(THREAD);
439 char* sig = target_method()->name_and_sig_as_C_string();
440 tty->print("overriding with %s::%s index %d, original flags: ",
441 target_klass->internal_name(), sig, i);
442 super_method->access_flags().print_on(tty);
443 if (super_method->is_default_method()) {
444 tty->print("default");
445 }
446 if (super_method->is_overpass()) {
447 tty->print("overpass");
448 }
449 tty->print("overriders flags: ");
450 target_method->access_flags().print_on(tty);
451 if (target_method->is_default_method()) {
452 tty->print("default");
453 }
454 if (target_method->is_overpass()) {
455 tty->print("overpass");
456 }
457 tty->cr();
458 }
459 #endif /*PRODUCT*/
460 } else {
461 // allocate_new = true; default. We might override one entry,
462 // but not override another. Once we override one, not need new
463 #ifndef PRODUCT
464 if (PrintVtables && Verbose) {
465 ResourceMark rm(THREAD);
466 char* sig = target_method()->name_and_sig_as_C_string();
467 tty->print("NOT overriding with %s::%s index %d, original flags: ",
468 target_klass->internal_name(), sig,i);
469 super_method->access_flags().print_on(tty);
470 if (super_method->is_default_method()) {
471 tty->print("default");
472 }
473 if (super_method->is_overpass()) {
474 tty->print("overpass");
475 }
476 tty->print("overriders flags: ");
477 target_method->access_flags().print_on(tty);
478 if (target_method->is_default_method()) {
479 tty->print("default");
480 }
481 if (target_method->is_overpass()) {
482 tty->print("overpass");
483 }
484 tty->cr();
485 }
486 #endif /*PRODUCT*/
487 }
488 }
489 }
490 return allocate_new;
491 }
493 void klassVtable::put_method_at(Method* m, int index) {
494 #ifndef PRODUCT
495 if (PrintVtables && Verbose) {
496 ResourceMark rm;
497 tty->print_cr("adding %s::%s at index %d", _klass->internal_name(),
498 (m != NULL) ? m->name()->as_C_string() : "<NULL>", index);
499 }
500 #endif
501 table()[index].set(m);
502 }
504 // Find out if a method "m" with superclass "super", loader "classloader" and
505 // name "classname" needs a new vtable entry. Let P be a class package defined
506 // by "classloader" and "classname".
507 // NOTE: The logic used here is very similar to the one used for computing
508 // the vtables indices for a method. We cannot directly use that function because,
509 // we allocate the InstanceKlass at load time, and that requires that the
510 // superclass has been loaded.
511 // However, the vtable entries are filled in at link time, and therefore
512 // the superclass' vtable may not yet have been filled in.
513 bool klassVtable::needs_new_vtable_entry(methodHandle target_method,
514 Klass* super,
515 Handle classloader,
516 Symbol* classname,
517 AccessFlags class_flags,
518 TRAPS) {
519 if (class_flags.is_interface()) {
520 // Interfaces do not use vtables, so there is no point to assigning
521 // a vtable index to any of their methods. If we refrain from doing this,
522 // we can use Method::_vtable_index to hold the itable index
523 return false;
524 }
526 if (target_method->is_final_method(class_flags) ||
527 // a final method never needs a new entry; final methods can be statically
528 // resolved and they have to be present in the vtable only if they override
529 // a super's method, in which case they re-use its entry
530 (target_method()->is_static()) ||
531 // static methods don't need to be in vtable
532 (target_method()->name() == vmSymbols::object_initializer_name())
533 // <init> is never called dynamically-bound
534 ) {
535 return false;
536 }
538 // Concrete interface methods do not need new entries, they override
539 // abstract method entries using default inheritance rules
540 if (target_method()->method_holder() != NULL &&
541 target_method()->method_holder()->is_interface() &&
542 !target_method()->is_abstract() ) {
543 return false;
544 }
546 // we need a new entry if there is no superclass
547 if (super == NULL) {
548 return true;
549 }
551 // private methods in classes always have a new entry in the vtable
552 // specification interpretation since classic has
553 // private methods not overriding
554 // JDK8 adds private methods in interfaces which require invokespecial
555 if (target_method()->is_private()) {
556 return true;
557 }
559 // search through the super class hierarchy to see if we need
560 // a new entry
561 ResourceMark rm;
562 Symbol* name = target_method()->name();
563 Symbol* signature = target_method()->signature();
564 Klass* k = super;
565 Method* super_method = NULL;
566 InstanceKlass *holder = NULL;
567 Method* recheck_method = NULL;
568 while (k != NULL) {
569 // lookup through the hierarchy for a method with matching name and sign.
570 super_method = InstanceKlass::cast(k)->lookup_method(name, signature);
571 if (super_method == NULL) {
572 break; // we still have to search for a matching miranda method
573 }
574 // get the class holding the matching method
575 // make sure you use that class for is_override
576 InstanceKlass* superk = super_method->method_holder();
577 // we want only instance method matches
578 // pretend private methods are not in the super vtable
579 // since we do override around them: e.g. a.m pub/b.m private/c.m pub,
580 // ignore private, c.m pub does override a.m pub
581 // For classes that were not javac'd together, we also do transitive overriding around
582 // methods that have less accessibility
583 if ((!super_method->is_static()) &&
584 (!super_method->is_private())) {
585 if (superk->is_override(super_method, classloader, classname, THREAD)) {
586 return false;
587 // else keep looking for transitive overrides
588 }
589 }
591 // Start with lookup result and continue to search up
592 k = superk->super(); // haven't found an override match yet; continue to look
593 }
595 // if the target method is public or protected it may have a matching
596 // miranda method in the super, whose entry it should re-use.
597 // Actually, to handle cases that javac would not generate, we need
598 // this check for all access permissions.
599 InstanceKlass *sk = InstanceKlass::cast(super);
600 if (sk->has_miranda_methods()) {
601 if (sk->lookup_method_in_all_interfaces(name, signature) != NULL) {
602 return false; // found a matching miranda; we do not need a new entry
603 }
604 }
605 return true; // found no match; we need a new entry
606 }
608 // Support for miranda methods
610 // get the vtable index of a miranda method with matching "name" and "signature"
611 int klassVtable::index_of_miranda(Symbol* name, Symbol* signature) {
612 // search from the bottom, might be faster
613 for (int i = (length() - 1); i >= 0; i--) {
614 Method* m = table()[i].method();
615 if (is_miranda_entry_at(i) &&
616 m->name() == name && m->signature() == signature) {
617 return i;
618 }
619 }
620 return Method::invalid_vtable_index;
621 }
623 // check if an entry at an index is miranda
624 // requires that method m at entry be declared ("held") by an interface.
625 bool klassVtable::is_miranda_entry_at(int i) {
626 Method* m = method_at(i);
627 Klass* method_holder = m->method_holder();
628 InstanceKlass *mhk = InstanceKlass::cast(method_holder);
630 // miranda methods are public abstract instance interface methods in a class's vtable
631 if (mhk->is_interface()) {
632 assert(m->is_public(), "should be public");
633 assert(ik()->implements_interface(method_holder) , "this class should implement the interface");
634 assert(is_miranda(m, ik()->methods(), ik()->default_methods(), ik()->super()), "should be a miranda_method");
635 return true;
636 }
637 return false;
638 }
640 // check if a method is a miranda method, given a class's methods table,
641 // its default_method table and its super
642 // "miranda" means not static, not defined by this class.
643 // private methods in interfaces do not belong in the miranda list.
644 // the caller must make sure that the method belongs to an interface implemented by the class
645 // Miranda methods only include public interface instance methods
646 // Not private methods, not static methods, not default == concrete abstract
647 bool klassVtable::is_miranda(Method* m, Array<Method*>* class_methods,
648 Array<Method*>* default_methods, Klass* super) {
649 if (m->is_static() || m->is_private()) {
650 return false;
651 }
652 Symbol* name = m->name();
653 Symbol* signature = m->signature();
654 if (InstanceKlass::find_method(class_methods, name, signature) == NULL) {
655 // did not find it in the method table of the current class
656 if ((default_methods == NULL) ||
657 InstanceKlass::find_method(default_methods, name, signature) == NULL) {
658 if (super == NULL) {
659 // super doesn't exist
660 return true;
661 }
663 Method* mo = InstanceKlass::cast(super)->lookup_method(name, signature);
664 if (mo == NULL || mo->access_flags().is_private() ) {
665 // super class hierarchy does not implement it or protection is different
666 return true;
667 }
668 }
669 }
671 return false;
672 }
674 // Scans current_interface_methods for miranda methods that do not
675 // already appear in new_mirandas, or default methods, and are also not defined-and-non-private
676 // in super (superclass). These mirandas are added to all_mirandas if it is
677 // not null; in addition, those that are not duplicates of miranda methods
678 // inherited by super from its interfaces are added to new_mirandas.
679 // Thus, new_mirandas will be the set of mirandas that this class introduces,
680 // all_mirandas will be the set of all mirandas applicable to this class
681 // including all defined in superclasses.
682 void klassVtable::add_new_mirandas_to_lists(
683 GrowableArray<Method*>* new_mirandas, GrowableArray<Method*>* all_mirandas,
684 Array<Method*>* current_interface_methods, Array<Method*>* class_methods,
685 Array<Method*>* default_methods, Klass* super) {
687 // iterate thru the current interface's method to see if it a miranda
688 int num_methods = current_interface_methods->length();
689 for (int i = 0; i < num_methods; i++) {
690 Method* im = current_interface_methods->at(i);
691 bool is_duplicate = false;
692 int num_of_current_mirandas = new_mirandas->length();
693 // check for duplicate mirandas in different interfaces we implement
694 for (int j = 0; j < num_of_current_mirandas; j++) {
695 Method* miranda = new_mirandas->at(j);
696 if ((im->name() == miranda->name()) &&
697 (im->signature() == miranda->signature())) {
698 is_duplicate = true;
699 break;
700 }
701 }
703 if (!is_duplicate) { // we don't want duplicate miranda entries in the vtable
704 if (is_miranda(im, class_methods, default_methods, super)) { // is it a miranda at all?
705 InstanceKlass *sk = InstanceKlass::cast(super);
706 // check if it is a duplicate of a super's miranda
707 if (sk->lookup_method_in_all_interfaces(im->name(), im->signature()) == NULL) {
708 new_mirandas->append(im);
709 }
710 if (all_mirandas != NULL) {
711 all_mirandas->append(im);
712 }
713 }
714 }
715 }
716 }
718 void klassVtable::get_mirandas(GrowableArray<Method*>* new_mirandas,
719 GrowableArray<Method*>* all_mirandas,
720 Klass* super, Array<Method*>* class_methods,
721 Array<Method*>* default_methods,
722 Array<Klass*>* local_interfaces) {
723 assert((new_mirandas->length() == 0) , "current mirandas must be 0");
725 // iterate thru the local interfaces looking for a miranda
726 int num_local_ifs = local_interfaces->length();
727 for (int i = 0; i < num_local_ifs; i++) {
728 InstanceKlass *ik = InstanceKlass::cast(local_interfaces->at(i));
729 add_new_mirandas_to_lists(new_mirandas, all_mirandas,
730 ik->methods(), class_methods,
731 default_methods, super);
732 // iterate thru each local's super interfaces
733 Array<Klass*>* super_ifs = ik->transitive_interfaces();
734 int num_super_ifs = super_ifs->length();
735 for (int j = 0; j < num_super_ifs; j++) {
736 InstanceKlass *sik = InstanceKlass::cast(super_ifs->at(j));
737 add_new_mirandas_to_lists(new_mirandas, all_mirandas,
738 sik->methods(), class_methods,
739 default_methods, super);
740 }
741 }
742 }
744 // Discover miranda methods ("miranda" = "interface abstract, no binding"),
745 // and append them into the vtable starting at index initialized,
746 // return the new value of initialized.
747 int klassVtable::fill_in_mirandas(int initialized) {
748 GrowableArray<Method*> mirandas(20);
749 get_mirandas(&mirandas, NULL, ik()->super(), ik()->methods(),
750 ik()->default_methods(), ik()->local_interfaces());
751 for (int i = 0; i < mirandas.length(); i++) {
752 if (PrintVtables && Verbose) {
753 Method* meth = mirandas.at(i);
754 ResourceMark rm(Thread::current());
755 if (meth != NULL) {
756 char* sig = meth->name_and_sig_as_C_string();
757 tty->print("fill in mirandas with %s index %d, flags: ",
758 sig, initialized);
759 meth->access_flags().print_on(tty);
760 if (meth->is_default_method()) {
761 tty->print("default");
762 }
763 tty->cr();
764 }
765 }
766 put_method_at(mirandas.at(i), initialized);
767 ++initialized;
768 }
769 return initialized;
770 }
772 // Copy this class's vtable to the vtable beginning at start.
773 // Used to copy superclass vtable to prefix of subclass's vtable.
774 void klassVtable::copy_vtable_to(vtableEntry* start) {
775 Copy::disjoint_words((HeapWord*)table(), (HeapWord*)start, _length * vtableEntry::size());
776 }
778 #if INCLUDE_JVMTI
779 bool klassVtable::adjust_default_method(int vtable_index, Method* old_method, Method* new_method) {
780 // If old_method is default, find this vtable index in default_vtable_indices
781 // and replace that method in the _default_methods list
782 bool updated = false;
784 Array<Method*>* default_methods = ik()->default_methods();
785 if (default_methods != NULL) {
786 int len = default_methods->length();
787 for (int idx = 0; idx < len; idx++) {
788 if (vtable_index == ik()->default_vtable_indices()->at(idx)) {
789 if (default_methods->at(idx) == old_method) {
790 default_methods->at_put(idx, new_method);
791 updated = true;
792 }
793 break;
794 }
795 }
796 }
797 return updated;
798 }
799 void klassVtable::adjust_method_entries(Method** old_methods, Method** new_methods,
800 int methods_length, bool * trace_name_printed) {
801 // search the vtable for uses of either obsolete or EMCP methods
802 for (int j = 0; j < methods_length; j++) {
803 Method* old_method = old_methods[j];
804 Method* new_method = new_methods[j];
806 // In the vast majority of cases we could get the vtable index
807 // by using: old_method->vtable_index()
808 // However, there are rare cases, eg. sun.awt.X11.XDecoratedPeer.getX()
809 // in sun.awt.X11.XFramePeer where methods occur more than once in the
810 // vtable, so, alas, we must do an exhaustive search.
811 for (int index = 0; index < length(); index++) {
812 if (unchecked_method_at(index) == old_method) {
813 put_method_at(new_method, index);
814 // For default methods, need to update the _default_methods array
815 // which can only have one method entry for a given signature
816 bool updated_default = false;
817 if (old_method->is_default_method()) {
818 updated_default = adjust_default_method(index, old_method, new_method);
819 }
821 if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
822 if (!(*trace_name_printed)) {
823 // RC_TRACE_MESG macro has an embedded ResourceMark
824 RC_TRACE_MESG(("adjust: klassname=%s for methods from name=%s",
825 klass()->external_name(),
826 old_method->method_holder()->external_name()));
827 *trace_name_printed = true;
828 }
829 // RC_TRACE macro has an embedded ResourceMark
830 RC_TRACE(0x00100000, ("vtable method update: %s(%s), updated default = %s",
831 new_method->name()->as_C_string(),
832 new_method->signature()->as_C_string(),
833 updated_default ? "true" : "false"));
834 }
835 // cannot 'break' here; see for-loop comment above.
836 }
837 }
838 }
839 }
841 // a vtable should never contain old or obsolete methods
842 bool klassVtable::check_no_old_or_obsolete_entries() {
843 for (int i = 0; i < length(); i++) {
844 Method* m = unchecked_method_at(i);
845 if (m != NULL &&
846 (NOT_PRODUCT(!m->is_valid() ||) m->is_old() || m->is_obsolete())) {
847 return false;
848 }
849 }
850 return true;
851 }
853 void klassVtable::dump_vtable() {
854 tty->print_cr("vtable dump --");
855 for (int i = 0; i < length(); i++) {
856 Method* m = unchecked_method_at(i);
857 if (m != NULL) {
858 tty->print(" (%5d) ", i);
859 m->access_flags().print_on(tty);
860 if (m->is_default_method()) {
861 tty->print("default");
862 }
863 if (m->is_overpass()) {
864 tty->print("overpass");
865 }
866 tty->print(" -- ");
867 m->print_name(tty);
868 tty->cr();
869 }
870 }
871 }
872 #endif // INCLUDE_JVMTI
874 // CDS/RedefineClasses support - clear vtables so they can be reinitialized
875 void klassVtable::clear_vtable() {
876 for (int i = 0; i < _length; i++) table()[i].clear();
877 }
879 bool klassVtable::is_initialized() {
880 return _length == 0 || table()[0].method() != NULL;
881 }
883 //-----------------------------------------------------------------------------------------
884 // Itable code
886 // Initialize a itableMethodEntry
887 void itableMethodEntry::initialize(Method* m) {
888 if (m == NULL) return;
890 _method = m;
891 }
893 klassItable::klassItable(instanceKlassHandle klass) {
894 _klass = klass;
896 if (klass->itable_length() > 0) {
897 itableOffsetEntry* offset_entry = (itableOffsetEntry*)klass->start_of_itable();
898 if (offset_entry != NULL && offset_entry->interface_klass() != NULL) { // Check that itable is initialized
899 // First offset entry points to the first method_entry
900 intptr_t* method_entry = (intptr_t *)(((address)klass()) + offset_entry->offset());
901 intptr_t* end = klass->end_of_itable();
903 _table_offset = (intptr_t*)offset_entry - (intptr_t*)klass();
904 _size_offset_table = (method_entry - ((intptr_t*)offset_entry)) / itableOffsetEntry::size();
905 _size_method_table = (end - method_entry) / itableMethodEntry::size();
906 assert(_table_offset >= 0 && _size_offset_table >= 0 && _size_method_table >= 0, "wrong computation");
907 return;
908 }
909 }
911 // The length of the itable was either zero, or it has not yet been initialized.
912 _table_offset = 0;
913 _size_offset_table = 0;
914 _size_method_table = 0;
915 }
917 static int initialize_count = 0;
919 // Initialization
920 void klassItable::initialize_itable(bool checkconstraints, TRAPS) {
921 if (_klass->is_interface()) {
922 // This needs to go after vtable indices are assigned but
923 // before implementors need to know the number of itable indices.
924 assign_itable_indices_for_interface(_klass());
925 }
927 // Cannot be setup doing bootstrapping, interfaces don't have
928 // itables, and klass with only ones entry have empty itables
929 if (Universe::is_bootstrapping() ||
930 _klass->is_interface() ||
931 _klass->itable_length() == itableOffsetEntry::size()) return;
933 // There's alway an extra itable entry so we can null-terminate it.
934 guarantee(size_offset_table() >= 1, "too small");
935 int num_interfaces = size_offset_table() - 1;
936 if (num_interfaces > 0) {
937 if (TraceItables) tty->print_cr("%3d: Initializing itables for %s", ++initialize_count,
938 _klass->name()->as_C_string());
941 // Iterate through all interfaces
942 int i;
943 for(i = 0; i < num_interfaces; i++) {
944 itableOffsetEntry* ioe = offset_entry(i);
945 HandleMark hm(THREAD);
946 KlassHandle interf_h (THREAD, ioe->interface_klass());
947 assert(interf_h() != NULL && ioe->offset() != 0, "bad offset entry in itable");
948 initialize_itable_for_interface(ioe->offset(), interf_h, checkconstraints, CHECK);
949 }
951 }
952 // Check that the last entry is empty
953 itableOffsetEntry* ioe = offset_entry(size_offset_table() - 1);
954 guarantee(ioe->interface_klass() == NULL && ioe->offset() == 0, "terminator entry missing");
955 }
958 inline bool interface_method_needs_itable_index(Method* m) {
959 if (m->is_static()) return false; // e.g., Stream.empty
960 if (m->is_initializer()) return false; // <init> or <clinit>
961 // If an interface redeclares a method from java.lang.Object,
962 // it should already have a vtable index, don't touch it.
963 // e.g., CharSequence.toString (from initialize_vtable)
964 // if (m->has_vtable_index()) return false; // NO!
965 return true;
966 }
968 int klassItable::assign_itable_indices_for_interface(Klass* klass) {
969 // an interface does not have an itable, but its methods need to be numbered
970 if (TraceItables) tty->print_cr("%3d: Initializing itable for interface %s", ++initialize_count,
971 klass->name()->as_C_string());
972 Array<Method*>* methods = InstanceKlass::cast(klass)->methods();
973 int nof_methods = methods->length();
974 int ime_num = 0;
975 for (int i = 0; i < nof_methods; i++) {
976 Method* m = methods->at(i);
977 if (interface_method_needs_itable_index(m)) {
978 assert(!m->is_final_method(), "no final interface methods");
979 // If m is already assigned a vtable index, do not disturb it.
980 if (!m->has_vtable_index()) {
981 assert(m->vtable_index() == Method::pending_itable_index, "set by initialize_vtable");
982 m->set_itable_index(ime_num);
983 // Progress to next itable entry
984 ime_num++;
985 }
986 }
987 }
988 assert(ime_num == method_count_for_interface(klass), "proper sizing");
989 return ime_num;
990 }
992 int klassItable::method_count_for_interface(Klass* interf) {
993 assert(interf->oop_is_instance(), "must be");
994 assert(interf->is_interface(), "must be");
995 Array<Method*>* methods = InstanceKlass::cast(interf)->methods();
996 int nof_methods = methods->length();
997 while (nof_methods > 0) {
998 Method* m = methods->at(nof_methods-1);
999 if (m->has_itable_index()) {
1000 int length = m->itable_index() + 1;
1001 #ifdef ASSERT
1002 while (nof_methods = 0) {
1003 m = methods->at(--nof_methods);
1004 assert(!m->has_itable_index() || m->itable_index() < length, "");
1005 }
1006 #endif //ASSERT
1007 return length; // return the rightmost itable index, plus one
1008 }
1009 nof_methods -= 1;
1010 }
1011 // no methods have itable indices
1012 return 0;
1013 }
1016 void klassItable::initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS) {
1017 Array<Method*>* methods = InstanceKlass::cast(interf_h())->methods();
1018 int nof_methods = methods->length();
1019 HandleMark hm;
1020 assert(nof_methods > 0, "at least one method must exist for interface to be in vtable");
1021 Handle interface_loader (THREAD, InstanceKlass::cast(interf_h())->class_loader());
1023 int ime_count = method_count_for_interface(interf_h());
1024 for (int i = 0; i < nof_methods; i++) {
1025 Method* m = methods->at(i);
1026 methodHandle target;
1027 if (m->has_itable_index()) {
1028 LinkResolver::lookup_instance_method_in_klasses(target, _klass, m->name(), m->signature(), CHECK);
1029 }
1030 if (target == NULL || !target->is_public() || target->is_abstract()) {
1031 // Entry do not resolve. Leave it empty
1032 } else {
1033 // Entry did resolve, check loader constraints before initializing
1034 // if checkconstraints requested
1035 if (checkconstraints) {
1036 Handle method_holder_loader (THREAD, target->method_holder()->class_loader());
1037 if (method_holder_loader() != interface_loader()) {
1038 ResourceMark rm(THREAD);
1039 Symbol* failed_type_symbol =
1040 SystemDictionary::check_signature_loaders(m->signature(),
1041 method_holder_loader,
1042 interface_loader,
1043 true, CHECK);
1044 if (failed_type_symbol != NULL) {
1045 const char* msg = "loader constraint violation in interface "
1046 "itable initialization: when resolving method \"%s\" the class"
1047 " loader (instance of %s) of the current class, %s, "
1048 "and the class loader (instance of %s) for interface "
1049 "%s have different Class objects for the type %s "
1050 "used in the signature";
1051 char* sig = target()->name_and_sig_as_C_string();
1052 const char* loader1 = SystemDictionary::loader_name(method_holder_loader());
1053 char* current = _klass->name()->as_C_string();
1054 const char* loader2 = SystemDictionary::loader_name(interface_loader());
1055 char* iface = InstanceKlass::cast(interf_h())->name()->as_C_string();
1056 char* failed_type_name = failed_type_symbol->as_C_string();
1057 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
1058 strlen(current) + strlen(loader2) + strlen(iface) +
1059 strlen(failed_type_name);
1060 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
1061 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2,
1062 iface, failed_type_name);
1063 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
1064 }
1065 }
1066 }
1068 // ime may have moved during GC so recalculate address
1069 int ime_num = m->itable_index();
1070 assert(ime_num < ime_count, "oob");
1071 itableOffsetEntry::method_entry(_klass(), method_table_offset)[ime_num].initialize(target());
1072 if (TraceItables && Verbose) {
1073 ResourceMark rm(THREAD);
1074 if (target() != NULL) {
1075 char* sig = target()->name_and_sig_as_C_string();
1076 tty->print("interface: %s, ime_num: %d, target: %s, method_holder: %s ",
1077 interf_h()->internal_name(), ime_num, sig,
1078 target()->method_holder()->internal_name());
1079 tty->print("target_method flags: ");
1080 target()->access_flags().print_on(tty);
1081 if (target()->is_default_method()) {
1082 tty->print("default");
1083 }
1084 tty->cr();
1085 }
1086 }
1087 }
1088 }
1089 }
1091 // Update entry for specific Method*
1092 void klassItable::initialize_with_method(Method* m) {
1093 itableMethodEntry* ime = method_entry(0);
1094 for(int i = 0; i < _size_method_table; i++) {
1095 if (ime->method() == m) {
1096 ime->initialize(m);
1097 }
1098 ime++;
1099 }
1100 }
1102 #if INCLUDE_JVMTI
1103 void klassItable::adjust_method_entries(Method** old_methods, Method** new_methods,
1104 int methods_length, bool * trace_name_printed) {
1105 // search the itable for uses of either obsolete or EMCP methods
1106 for (int j = 0; j < methods_length; j++) {
1107 Method* old_method = old_methods[j];
1108 Method* new_method = new_methods[j];
1109 itableMethodEntry* ime = method_entry(0);
1111 // The itable can describe more than one interface and the same
1112 // method signature can be specified by more than one interface.
1113 // This means we have to do an exhaustive search to find all the
1114 // old_method references.
1115 for (int i = 0; i < _size_method_table; i++) {
1116 if (ime->method() == old_method) {
1117 ime->initialize(new_method);
1119 if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
1120 if (!(*trace_name_printed)) {
1121 // RC_TRACE_MESG macro has an embedded ResourceMark
1122 RC_TRACE_MESG(("adjust: name=%s",
1123 old_method->method_holder()->external_name()));
1124 *trace_name_printed = true;
1125 }
1126 // RC_TRACE macro has an embedded ResourceMark
1127 RC_TRACE(0x00200000, ("itable method update: %s(%s)",
1128 new_method->name()->as_C_string(),
1129 new_method->signature()->as_C_string()));
1130 }
1131 // cannot 'break' here; see for-loop comment above.
1132 }
1133 ime++;
1134 }
1135 }
1136 }
1138 // an itable should never contain old or obsolete methods
1139 bool klassItable::check_no_old_or_obsolete_entries() {
1140 itableMethodEntry* ime = method_entry(0);
1141 for (int i = 0; i < _size_method_table; i++) {
1142 Method* m = ime->method();
1143 if (m != NULL &&
1144 (NOT_PRODUCT(!m->is_valid() ||) m->is_old() || m->is_obsolete())) {
1145 return false;
1146 }
1147 ime++;
1148 }
1149 return true;
1150 }
1152 void klassItable::dump_itable() {
1153 itableMethodEntry* ime = method_entry(0);
1154 tty->print_cr("itable dump --");
1155 for (int i = 0; i < _size_method_table; i++) {
1156 Method* m = ime->method();
1157 if (m != NULL) {
1158 tty->print(" (%5d) ", i);
1159 m->access_flags().print_on(tty);
1160 if (m->is_default_method()) {
1161 tty->print("default");
1162 }
1163 tty->print(" -- ");
1164 m->print_name(tty);
1165 tty->cr();
1166 }
1167 ime++;
1168 }
1169 }
1170 #endif // INCLUDE_JVMTI
1173 // Setup
1174 class InterfaceVisiterClosure : public StackObj {
1175 public:
1176 virtual void doit(Klass* intf, int method_count) = 0;
1177 };
1179 // Visit all interfaces with at least one itable method
1180 void visit_all_interfaces(Array<Klass*>* transitive_intf, InterfaceVisiterClosure *blk) {
1181 // Handle array argument
1182 for(int i = 0; i < transitive_intf->length(); i++) {
1183 Klass* intf = transitive_intf->at(i);
1184 assert(intf->is_interface(), "sanity check");
1186 // Find no. of itable methods
1187 int method_count = 0;
1188 // method_count = klassItable::method_count_for_interface(intf);
1189 Array<Method*>* methods = InstanceKlass::cast(intf)->methods();
1190 if (methods->length() > 0) {
1191 for (int i = methods->length(); --i >= 0; ) {
1192 if (interface_method_needs_itable_index(methods->at(i))) {
1193 method_count++;
1194 }
1195 }
1196 }
1198 // Only count interfaces with at least one method
1199 if (method_count > 0) {
1200 blk->doit(intf, method_count);
1201 }
1202 }
1203 }
1205 class CountInterfacesClosure : public InterfaceVisiterClosure {
1206 private:
1207 int _nof_methods;
1208 int _nof_interfaces;
1209 public:
1210 CountInterfacesClosure() { _nof_methods = 0; _nof_interfaces = 0; }
1212 int nof_methods() const { return _nof_methods; }
1213 int nof_interfaces() const { return _nof_interfaces; }
1215 void doit(Klass* intf, int method_count) { _nof_methods += method_count; _nof_interfaces++; }
1216 };
1218 class SetupItableClosure : public InterfaceVisiterClosure {
1219 private:
1220 itableOffsetEntry* _offset_entry;
1221 itableMethodEntry* _method_entry;
1222 address _klass_begin;
1223 public:
1224 SetupItableClosure(address klass_begin, itableOffsetEntry* offset_entry, itableMethodEntry* method_entry) {
1225 _klass_begin = klass_begin;
1226 _offset_entry = offset_entry;
1227 _method_entry = method_entry;
1228 }
1230 itableMethodEntry* method_entry() const { return _method_entry; }
1232 void doit(Klass* intf, int method_count) {
1233 int offset = ((address)_method_entry) - _klass_begin;
1234 _offset_entry->initialize(intf, offset);
1235 _offset_entry++;
1236 _method_entry += method_count;
1237 }
1238 };
1240 int klassItable::compute_itable_size(Array<Klass*>* transitive_interfaces) {
1241 // Count no of interfaces and total number of interface methods
1242 CountInterfacesClosure cic;
1243 visit_all_interfaces(transitive_interfaces, &cic);
1245 // There's alway an extra itable entry so we can null-terminate it.
1246 int itable_size = calc_itable_size(cic.nof_interfaces() + 1, cic.nof_methods());
1248 // Statistics
1249 update_stats(itable_size * HeapWordSize);
1251 return itable_size;
1252 }
1255 // Fill out offset table and interface klasses into the itable space
1256 void klassItable::setup_itable_offset_table(instanceKlassHandle klass) {
1257 if (klass->itable_length() == 0) return;
1258 assert(!klass->is_interface(), "Should have zero length itable");
1260 // Count no of interfaces and total number of interface methods
1261 CountInterfacesClosure cic;
1262 visit_all_interfaces(klass->transitive_interfaces(), &cic);
1263 int nof_methods = cic.nof_methods();
1264 int nof_interfaces = cic.nof_interfaces();
1266 // Add one extra entry so we can null-terminate the table
1267 nof_interfaces++;
1269 assert(compute_itable_size(klass->transitive_interfaces()) ==
1270 calc_itable_size(nof_interfaces, nof_methods),
1271 "mismatch calculation of itable size");
1273 // Fill-out offset table
1274 itableOffsetEntry* ioe = (itableOffsetEntry*)klass->start_of_itable();
1275 itableMethodEntry* ime = (itableMethodEntry*)(ioe + nof_interfaces);
1276 intptr_t* end = klass->end_of_itable();
1277 assert((oop*)(ime + nof_methods) <= (oop*)klass->start_of_nonstatic_oop_maps(), "wrong offset calculation (1)");
1278 assert((oop*)(end) == (oop*)(ime + nof_methods), "wrong offset calculation (2)");
1280 // Visit all interfaces and initialize itable offset table
1281 SetupItableClosure sic((address)klass(), ioe, ime);
1282 visit_all_interfaces(klass->transitive_interfaces(), &sic);
1284 #ifdef ASSERT
1285 ime = sic.method_entry();
1286 oop* v = (oop*) klass->end_of_itable();
1287 assert( (oop*)(ime) == v, "wrong offset calculation (2)");
1288 #endif
1289 }
1292 // inverse to itable_index
1293 Method* klassItable::method_for_itable_index(Klass* intf, int itable_index) {
1294 assert(InstanceKlass::cast(intf)->is_interface(), "sanity check");
1295 assert(intf->verify_itable_index(itable_index), "");
1296 Array<Method*>* methods = InstanceKlass::cast(intf)->methods();
1298 if (itable_index < 0 || itable_index >= method_count_for_interface(intf))
1299 return NULL; // help caller defend against bad indices
1301 int index = itable_index;
1302 Method* m = methods->at(index);
1303 int index2 = -1;
1304 while (!m->has_itable_index() ||
1305 (index2 = m->itable_index()) != itable_index) {
1306 assert(index2 < itable_index, "monotonic");
1307 if (++index == methods->length())
1308 return NULL;
1309 m = methods->at(index);
1310 }
1311 assert(m->itable_index() == itable_index, "correct inverse");
1313 return m;
1314 }
1316 void klassVtable::verify(outputStream* st, bool forced) {
1317 // make sure table is initialized
1318 if (!Universe::is_fully_initialized()) return;
1319 #ifndef PRODUCT
1320 // avoid redundant verifies
1321 if (!forced && _verify_count == Universe::verify_count()) return;
1322 _verify_count = Universe::verify_count();
1323 #endif
1324 oop* end_of_obj = (oop*)_klass() + _klass()->size();
1325 oop* end_of_vtable = (oop *)&table()[_length];
1326 if (end_of_vtable > end_of_obj) {
1327 fatal(err_msg("klass %s: klass object too short (vtable extends beyond "
1328 "end)", _klass->internal_name()));
1329 }
1331 for (int i = 0; i < _length; i++) table()[i].verify(this, st);
1332 // verify consistency with superKlass vtable
1333 Klass* super = _klass->super();
1334 if (super != NULL) {
1335 InstanceKlass* sk = InstanceKlass::cast(super);
1336 klassVtable* vt = sk->vtable();
1337 for (int i = 0; i < vt->length(); i++) {
1338 verify_against(st, vt, i);
1339 }
1340 }
1341 }
1343 void klassVtable::verify_against(outputStream* st, klassVtable* vt, int index) {
1344 vtableEntry* vte = &vt->table()[index];
1345 if (vte->method()->name() != table()[index].method()->name() ||
1346 vte->method()->signature() != table()[index].method()->signature()) {
1347 fatal("mismatched name/signature of vtable entries");
1348 }
1349 }
1351 #ifndef PRODUCT
1352 void klassVtable::print() {
1353 ResourceMark rm;
1354 tty->print("klassVtable for klass %s (length %d):\n", _klass->internal_name(), length());
1355 for (int i = 0; i < length(); i++) {
1356 table()[i].print();
1357 tty->cr();
1358 }
1359 }
1360 #endif
1362 void vtableEntry::verify(klassVtable* vt, outputStream* st) {
1363 NOT_PRODUCT(FlagSetting fs(IgnoreLockingAssertions, true));
1364 assert(method() != NULL, "must have set method");
1365 method()->verify();
1366 // we sub_type, because it could be a miranda method
1367 if (!vt->klass()->is_subtype_of(method()->method_holder())) {
1368 #ifndef PRODUCT
1369 print();
1370 #endif
1371 fatal(err_msg("vtableEntry " PTR_FORMAT ": method is from subclass", this));
1372 }
1373 }
1375 #ifndef PRODUCT
1377 void vtableEntry::print() {
1378 ResourceMark rm;
1379 tty->print("vtableEntry %s: ", method()->name()->as_C_string());
1380 if (Verbose) {
1381 tty->print("m %#lx ", (address)method());
1382 }
1383 }
1385 class VtableStats : AllStatic {
1386 public:
1387 static int no_klasses; // # classes with vtables
1388 static int no_array_klasses; // # array classes
1389 static int no_instance_klasses; // # instanceKlasses
1390 static int sum_of_vtable_len; // total # of vtable entries
1391 static int sum_of_array_vtable_len; // total # of vtable entries in array klasses only
1392 static int fixed; // total fixed overhead in bytes
1393 static int filler; // overhead caused by filler bytes
1394 static int entries; // total bytes consumed by vtable entries
1395 static int array_entries; // total bytes consumed by array vtable entries
1397 static void do_class(Klass* k) {
1398 Klass* kl = k;
1399 klassVtable* vt = kl->vtable();
1400 if (vt == NULL) return;
1401 no_klasses++;
1402 if (kl->oop_is_instance()) {
1403 no_instance_klasses++;
1404 kl->array_klasses_do(do_class);
1405 }
1406 if (kl->oop_is_array()) {
1407 no_array_klasses++;
1408 sum_of_array_vtable_len += vt->length();
1409 }
1410 sum_of_vtable_len += vt->length();
1411 }
1413 static void compute() {
1414 SystemDictionary::classes_do(do_class);
1415 fixed = no_klasses * oopSize; // vtable length
1416 // filler size is a conservative approximation
1417 filler = oopSize * (no_klasses - no_instance_klasses) * (sizeof(InstanceKlass) - sizeof(ArrayKlass) - 1);
1418 entries = sizeof(vtableEntry) * sum_of_vtable_len;
1419 array_entries = sizeof(vtableEntry) * sum_of_array_vtable_len;
1420 }
1421 };
1423 int VtableStats::no_klasses = 0;
1424 int VtableStats::no_array_klasses = 0;
1425 int VtableStats::no_instance_klasses = 0;
1426 int VtableStats::sum_of_vtable_len = 0;
1427 int VtableStats::sum_of_array_vtable_len = 0;
1428 int VtableStats::fixed = 0;
1429 int VtableStats::filler = 0;
1430 int VtableStats::entries = 0;
1431 int VtableStats::array_entries = 0;
1433 void klassVtable::print_statistics() {
1434 ResourceMark rm;
1435 HandleMark hm;
1436 VtableStats::compute();
1437 tty->print_cr("vtable statistics:");
1438 tty->print_cr("%6d classes (%d instance, %d array)", VtableStats::no_klasses, VtableStats::no_instance_klasses, VtableStats::no_array_klasses);
1439 int total = VtableStats::fixed + VtableStats::filler + VtableStats::entries;
1440 tty->print_cr("%6d bytes fixed overhead (refs + vtable object header)", VtableStats::fixed);
1441 tty->print_cr("%6d bytes filler overhead", VtableStats::filler);
1442 tty->print_cr("%6d bytes for vtable entries (%d for arrays)", VtableStats::entries, VtableStats::array_entries);
1443 tty->print_cr("%6d bytes total", total);
1444 }
1446 int klassItable::_total_classes; // Total no. of classes with itables
1447 long klassItable::_total_size; // Total no. of bytes used for itables
1449 void klassItable::print_statistics() {
1450 tty->print_cr("itable statistics:");
1451 tty->print_cr("%6d classes with itables", _total_classes);
1452 tty->print_cr("%6d K uses for itables (average by class: %d bytes)", _total_size / K, _total_size / _total_classes);
1453 }
1455 #endif // PRODUCT