Tue, 25 Feb 2014 18:16:24 +0100
8031752: Failed speculative optimizations should be reattempted when root of compilation is different
Summary: support for speculative traps that keep track of the root of the compilation in which a trap occurs.
Reviewed-by: kvn, twisti
1 /*
2 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
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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 // Interfaces do not need interface methods in their vtables
90 // This includes miranda methods and during later processing, default methods
91 if (!class_flags.is_interface()) {
92 vtable_length += *num_new_mirandas * vtableEntry::size();
93 }
95 if (Universe::is_bootstrapping() && vtable_length == 0) {
96 // array classes don't have their superclass set correctly during
97 // bootstrapping
98 vtable_length = Universe::base_vtable_size();
99 }
101 if (super == NULL && !Universe::is_bootstrapping() &&
102 vtable_length != Universe::base_vtable_size()) {
103 // Someone is attempting to redefine java.lang.Object incorrectly. The
104 // only way this should happen is from
105 // SystemDictionary::resolve_from_stream(), which will detect this later
106 // and throw a security exception. So don't assert here to let
107 // the exception occur.
108 vtable_length = Universe::base_vtable_size();
109 }
110 assert(super != NULL || vtable_length == Universe::base_vtable_size(),
111 "bad vtable size for class Object");
112 assert(vtable_length % vtableEntry::size() == 0, "bad vtable length");
113 assert(vtable_length >= Universe::base_vtable_size(), "vtable too small");
115 *vtable_length_ret = vtable_length;
116 }
118 int klassVtable::index_of(Method* m, int len) const {
119 assert(m->has_vtable_index(), "do not ask this of non-vtable methods");
120 return m->vtable_index();
121 }
123 // Copy super class's vtable to the first part (prefix) of this class's vtable,
124 // and return the number of entries copied. Expects that 'super' is the Java
125 // super class (arrays can have "array" super classes that must be skipped).
126 int klassVtable::initialize_from_super(KlassHandle super) {
127 if (super.is_null()) {
128 return 0;
129 } else {
130 // copy methods from superKlass
131 // can't inherit from array class, so must be InstanceKlass
132 assert(super->oop_is_instance(), "must be instance klass");
133 InstanceKlass* sk = (InstanceKlass*)super();
134 klassVtable* superVtable = sk->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 #ifndef PRODUCT
141 if (PrintVtables && Verbose) {
142 ResourceMark rm;
143 tty->print_cr("copy vtable from %s to %s size %d", sk->internal_name(), klass()->internal_name(), _length);
144 }
145 #endif
146 return superVtable->length();
147 }
148 }
150 //
151 // Revised lookup semantics introduced 1.3 (Kestrel beta)
152 void klassVtable::initialize_vtable(bool checkconstraints, TRAPS) {
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;
158 if (PrintVtables && !klass()->oop_is_array()) {
159 ResourceMark rm(THREAD);
160 tty->print_cr("Initializing: %s", _klass->name()->as_C_string());
161 }
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
169 if (Universe::is_bootstrapping()) {
170 // just clear everything
171 for (int i = 0; i < _length; i++) table()[i].clear();
172 return;
173 }
175 int super_vtable_len = initialize_from_super(super);
176 if (klass()->oop_is_array()) {
177 assert(super_vtable_len == _length, "arrays shouldn't introduce new methods");
178 } else {
179 assert(_klass->oop_is_instance(), "must be InstanceKlass");
181 Array<Method*>* methods = ik()->methods();
182 int len = methods->length();
183 int initialized = super_vtable_len;
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));
193 bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, -1, checkconstraints, CHECK);
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 }
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));
218 bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, i, checkconstraints, CHECK);
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 }
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 }
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 }
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 InstanceKlass* klassVtable::find_transitive_override(InstanceKlass* initialsuper, methodHandle target_method,
253 int vtable_index, Handle target_loader, Symbol* target_classname, Thread * THREAD) {
254 InstanceKlass* superk = initialsuper;
255 while (superk != NULL && superk->super() != NULL) {
256 InstanceKlass* supersuperklass = InstanceKlass::cast(superk->super());
257 klassVtable* ssVtable = supersuperklass->vtable();
258 if (vtable_index < ssVtable->length()) {
259 Method* super_method = ssVtable->method_at(vtable_index);
260 #ifndef PRODUCT
261 Symbol* name= target_method()->name();
262 Symbol* signature = target_method()->signature();
263 assert(super_method->name() == name && super_method->signature() == signature, "vtable entry name/sig mismatch");
264 #endif
265 if (supersuperklass->is_override(super_method, target_loader, target_classname, THREAD)) {
266 #ifndef PRODUCT
267 if (PrintVtables && Verbose) {
268 ResourceMark rm(THREAD);
269 char* sig = target_method()->name_and_sig_as_C_string();
270 tty->print("transitive overriding superclass %s with %s::%s index %d, original flags: ",
271 supersuperklass->internal_name(),
272 _klass->internal_name(), sig, vtable_index);
273 super_method->access_flags().print_on(tty);
274 if (super_method->is_default_method()) {
275 tty->print("default ");
276 }
277 tty->print("overriders flags: ");
278 target_method->access_flags().print_on(tty);
279 if (target_method->is_default_method()) {
280 tty->print("default ");
281 }
282 }
283 #endif /*PRODUCT*/
284 break; // return found superk
285 }
286 } else {
287 // super class has no vtable entry here, stop transitive search
288 superk = (InstanceKlass*)NULL;
289 break;
290 }
291 // if no override found yet, continue to search up
292 superk = InstanceKlass::cast(superk->super());
293 }
295 return superk;
296 }
298 // Update child's copy of super vtable for overrides
299 // OR return true if a new vtable entry is required.
300 // Only called for InstanceKlass's, i.e. not for arrays
301 // If that changed, could not use _klass as handle for klass
302 bool klassVtable::update_inherited_vtable(InstanceKlass* klass, methodHandle target_method,
303 int super_vtable_len, int default_index,
304 bool checkconstraints, TRAPS) {
305 ResourceMark rm;
306 bool allocate_new = true;
307 assert(klass->oop_is_instance(), "must be InstanceKlass");
309 Array<int>* def_vtable_indices = NULL;
310 bool is_default = false;
311 // default methods are concrete methods in superinterfaces which are added to the vtable
312 // with their real method_holder
313 // Since vtable and itable indices share the same storage, don't touch
314 // the default method's real vtable/itable index
315 // default_vtable_indices stores the vtable value relative to this inheritor
316 if (default_index >= 0 ) {
317 is_default = true;
318 def_vtable_indices = klass->default_vtable_indices();
319 assert(def_vtable_indices != NULL, "def vtable alloc?");
320 assert(default_index <= def_vtable_indices->length(), "def vtable len?");
321 } else {
322 assert(klass == target_method()->method_holder(), "caller resp.");
323 // Initialize the method's vtable index to "nonvirtual".
324 // If we allocate a vtable entry, we will update it to a non-negative number.
325 target_method()->set_vtable_index(Method::nonvirtual_vtable_index);
326 }
328 // Static and <init> methods are never in
329 if (target_method()->is_static() || target_method()->name() == vmSymbols::object_initializer_name()) {
330 return false;
331 }
333 if (target_method->is_final_method(klass->access_flags())) {
334 // a final method never needs a new entry; final methods can be statically
335 // resolved and they have to be present in the vtable only if they override
336 // a super's method, in which case they re-use its entry
337 allocate_new = false;
338 } else if (klass->is_interface()) {
339 allocate_new = false; // see note below in needs_new_vtable_entry
340 // An interface never allocates new vtable slots, only inherits old ones.
341 // This method will either be assigned its own itable index later,
342 // or be assigned an inherited vtable index in the loop below.
343 // default methods inherited by classes store their vtable indices
344 // in the inheritor's default_vtable_indices
345 // default methods inherited by interfaces may already have a
346 // valid itable index, if so, don't change it
347 // overpass methods in an interface will be assigned an itable index later
348 // by an inheriting class
349 if (!is_default || !target_method()->has_itable_index()) {
350 target_method()->set_vtable_index(Method::pending_itable_index);
351 }
352 }
354 // we need a new entry if there is no superclass
355 if (klass->super() == NULL) {
356 return allocate_new;
357 }
359 // private methods in classes always have a new entry in the vtable
360 // specification interpretation since classic has
361 // private methods not overriding
362 // JDK8 adds private methods in interfaces which require invokespecial
363 if (target_method()->is_private()) {
364 return allocate_new;
365 }
367 // search through the vtable and update overridden entries
368 // Since check_signature_loaders acquires SystemDictionary_lock
369 // which can block for gc, once we are in this loop, use handles
370 // For classfiles built with >= jdk7, we now look for transitive overrides
372 Symbol* name = target_method()->name();
373 Symbol* signature = target_method()->signature();
375 KlassHandle target_klass(THREAD, target_method()->method_holder());
376 if (target_klass == NULL) {
377 target_klass = _klass;
378 }
380 Handle target_loader(THREAD, target_klass->class_loader());
382 Symbol* target_classname = target_klass->name();
383 for(int i = 0; i < super_vtable_len; i++) {
384 Method* super_method = method_at(i);
385 // Check if method name matches
386 if (super_method->name() == name && super_method->signature() == signature) {
388 // get super_klass for method_holder for the found method
389 InstanceKlass* super_klass = super_method->method_holder();
391 if (is_default
392 || ((super_klass->is_override(super_method, target_loader, target_classname, THREAD))
393 || ((klass->major_version() >= VTABLE_TRANSITIVE_OVERRIDE_VERSION)
394 && ((super_klass = find_transitive_override(super_klass,
395 target_method, i, target_loader,
396 target_classname, THREAD))
397 != (InstanceKlass*)NULL))))
398 {
399 // overriding, so no new entry
400 allocate_new = false;
402 if (checkconstraints) {
403 // Override vtable entry if passes loader constraint check
404 // if loader constraint checking requested
405 // No need to visit his super, since he and his super
406 // have already made any needed loader constraints.
407 // Since loader constraints are transitive, it is enough
408 // to link to the first super, and we get all the others.
409 Handle super_loader(THREAD, super_klass->class_loader());
411 if (target_loader() != super_loader()) {
412 ResourceMark rm(THREAD);
413 Symbol* failed_type_symbol =
414 SystemDictionary::check_signature_loaders(signature, target_loader,
415 super_loader, true,
416 CHECK_(false));
417 if (failed_type_symbol != NULL) {
418 const char* msg = "loader constraint violation: when resolving "
419 "overridden method \"%s\" the class loader (instance"
420 " of %s) of the current class, %s, and its superclass loader "
421 "(instance of %s), have different Class objects for the type "
422 "%s used in the signature";
423 char* sig = target_method()->name_and_sig_as_C_string();
424 const char* loader1 = SystemDictionary::loader_name(target_loader());
425 char* current = target_klass->name()->as_C_string();
426 const char* loader2 = SystemDictionary::loader_name(super_loader());
427 char* failed_type_name = failed_type_symbol->as_C_string();
428 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
429 strlen(current) + strlen(loader2) + strlen(failed_type_name);
430 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
431 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2,
432 failed_type_name);
433 THROW_MSG_(vmSymbols::java_lang_LinkageError(), buf, false);
434 }
435 }
436 }
438 put_method_at(target_method(), i);
439 if (!is_default) {
440 target_method()->set_vtable_index(i);
441 } else {
442 if (def_vtable_indices != NULL) {
443 def_vtable_indices->at_put(default_index, i);
444 }
445 assert(super_method->is_default_method() || super_method->is_overpass()
446 || super_method->is_abstract(), "default override error");
447 }
450 #ifndef PRODUCT
451 if (PrintVtables && Verbose) {
452 ResourceMark rm(THREAD);
453 char* sig = target_method()->name_and_sig_as_C_string();
454 tty->print("overriding with %s::%s index %d, original flags: ",
455 target_klass->internal_name(), sig, i);
456 super_method->access_flags().print_on(tty);
457 if (super_method->is_default_method()) {
458 tty->print("default ");
459 }
460 if (super_method->is_overpass()) {
461 tty->print("overpass");
462 }
463 tty->print("overriders flags: ");
464 target_method->access_flags().print_on(tty);
465 if (target_method->is_default_method()) {
466 tty->print("default ");
467 }
468 if (target_method->is_overpass()) {
469 tty->print("overpass");
470 }
471 tty->cr();
472 }
473 #endif /*PRODUCT*/
474 } else {
475 // allocate_new = true; default. We might override one entry,
476 // but not override another. Once we override one, not need new
477 #ifndef PRODUCT
478 if (PrintVtables && Verbose) {
479 ResourceMark rm(THREAD);
480 char* sig = target_method()->name_and_sig_as_C_string();
481 tty->print("NOT overriding with %s::%s index %d, original flags: ",
482 target_klass->internal_name(), sig,i);
483 super_method->access_flags().print_on(tty);
484 if (super_method->is_default_method()) {
485 tty->print("default ");
486 }
487 if (super_method->is_overpass()) {
488 tty->print("overpass");
489 }
490 tty->print("overriders flags: ");
491 target_method->access_flags().print_on(tty);
492 if (target_method->is_default_method()) {
493 tty->print("default ");
494 }
495 if (target_method->is_overpass()) {
496 tty->print("overpass");
497 }
498 tty->cr();
499 }
500 #endif /*PRODUCT*/
501 }
502 }
503 }
504 return allocate_new;
505 }
507 void klassVtable::put_method_at(Method* m, int index) {
508 #ifndef PRODUCT
509 if (PrintVtables && Verbose) {
510 ResourceMark rm;
511 const char* sig = (m != NULL) ? m->name_and_sig_as_C_string() : "<NULL>";
512 tty->print("adding %s at index %d, flags: ", sig, index);
513 if (m != NULL) {
514 m->access_flags().print_on(tty);
515 if (m->is_default_method()) {
516 tty->print("default ");
517 }
518 if (m->is_overpass()) {
519 tty->print("overpass");
520 }
521 }
522 tty->cr();
523 }
524 #endif
525 table()[index].set(m);
526 }
528 // Find out if a method "m" with superclass "super", loader "classloader" and
529 // name "classname" needs a new vtable entry. Let P be a class package defined
530 // by "classloader" and "classname".
531 // NOTE: The logic used here is very similar to the one used for computing
532 // the vtables indices for a method. We cannot directly use that function because,
533 // we allocate the InstanceKlass at load time, and that requires that the
534 // superclass has been loaded.
535 // However, the vtable entries are filled in at link time, and therefore
536 // the superclass' vtable may not yet have been filled in.
537 bool klassVtable::needs_new_vtable_entry(methodHandle target_method,
538 Klass* super,
539 Handle classloader,
540 Symbol* classname,
541 AccessFlags class_flags,
542 TRAPS) {
543 if (class_flags.is_interface()) {
544 // Interfaces do not use vtables, so there is no point to assigning
545 // a vtable index to any of their methods. If we refrain from doing this,
546 // we can use Method::_vtable_index to hold the itable index
547 return false;
548 }
550 if (target_method->is_final_method(class_flags) ||
551 // a final method never needs a new entry; final methods can be statically
552 // resolved and they have to be present in the vtable only if they override
553 // a super's method, in which case they re-use its entry
554 (target_method()->is_static()) ||
555 // static methods don't need to be in vtable
556 (target_method()->name() == vmSymbols::object_initializer_name())
557 // <init> is never called dynamically-bound
558 ) {
559 return false;
560 }
562 // Concrete interface methods do not need new entries, they override
563 // abstract method entries using default inheritance rules
564 if (target_method()->method_holder() != NULL &&
565 target_method()->method_holder()->is_interface() &&
566 !target_method()->is_abstract() ) {
567 return false;
568 }
570 // we need a new entry if there is no superclass
571 if (super == NULL) {
572 return true;
573 }
575 // private methods in classes always have a new entry in the vtable
576 // specification interpretation since classic has
577 // private methods not overriding
578 // JDK8 adds private methods in interfaces which require invokespecial
579 if (target_method()->is_private()) {
580 return true;
581 }
583 // search through the super class hierarchy to see if we need
584 // a new entry
585 ResourceMark rm;
586 Symbol* name = target_method()->name();
587 Symbol* signature = target_method()->signature();
588 Klass* k = super;
589 Method* super_method = NULL;
590 InstanceKlass *holder = NULL;
591 Method* recheck_method = NULL;
592 while (k != NULL) {
593 // lookup through the hierarchy for a method with matching name and sign.
594 super_method = InstanceKlass::cast(k)->lookup_method(name, signature);
595 if (super_method == NULL) {
596 break; // we still have to search for a matching miranda method
597 }
598 // get the class holding the matching method
599 // make sure you use that class for is_override
600 InstanceKlass* superk = super_method->method_holder();
601 // we want only instance method matches
602 // pretend private methods are not in the super vtable
603 // since we do override around them: e.g. a.m pub/b.m private/c.m pub,
604 // ignore private, c.m pub does override a.m pub
605 // For classes that were not javac'd together, we also do transitive overriding around
606 // methods that have less accessibility
607 if ((!super_method->is_static()) &&
608 (!super_method->is_private())) {
609 if (superk->is_override(super_method, classloader, classname, THREAD)) {
610 return false;
611 // else keep looking for transitive overrides
612 }
613 }
615 // Start with lookup result and continue to search up
616 k = superk->super(); // haven't found an override match yet; continue to look
617 }
619 // if the target method is public or protected it may have a matching
620 // miranda method in the super, whose entry it should re-use.
621 // Actually, to handle cases that javac would not generate, we need
622 // this check for all access permissions.
623 InstanceKlass *sk = InstanceKlass::cast(super);
624 if (sk->has_miranda_methods()) {
625 if (sk->lookup_method_in_all_interfaces(name, signature, false) != NULL) {
626 return false; // found a matching miranda; we do not need a new entry
627 }
628 }
629 return true; // found no match; we need a new entry
630 }
632 // Support for miranda methods
634 // get the vtable index of a miranda method with matching "name" and "signature"
635 int klassVtable::index_of_miranda(Symbol* name, Symbol* signature) {
636 // search from the bottom, might be faster
637 for (int i = (length() - 1); i >= 0; i--) {
638 Method* m = table()[i].method();
639 if (is_miranda_entry_at(i) &&
640 m->name() == name && m->signature() == signature) {
641 return i;
642 }
643 }
644 return Method::invalid_vtable_index;
645 }
647 // check if an entry at an index is miranda
648 // requires that method m at entry be declared ("held") by an interface.
649 bool klassVtable::is_miranda_entry_at(int i) {
650 Method* m = method_at(i);
651 Klass* method_holder = m->method_holder();
652 InstanceKlass *mhk = InstanceKlass::cast(method_holder);
654 // miranda methods are public abstract instance interface methods in a class's vtable
655 if (mhk->is_interface()) {
656 assert(m->is_public(), "should be public");
657 assert(ik()->implements_interface(method_holder) , "this class should implement the interface");
658 // the search could find a miranda or a default method
659 if (is_miranda(m, ik()->methods(), ik()->default_methods(), ik()->super())) {
660 return true;
661 }
662 }
663 return false;
664 }
666 // check if a method is a miranda method, given a class's methods table,
667 // its default_method table and its super
668 // Miranda methods are calculated twice:
669 // first: before vtable size calculation: including abstract and default
670 // This is seen by default method creation
671 // Second: recalculated during vtable initialization: only abstract
672 // This is seen by link resolution and selection.
673 // "miranda" means not static, not defined by this class.
674 // private methods in interfaces do not belong in the miranda list.
675 // the caller must make sure that the method belongs to an interface implemented by the class
676 // Miranda methods only include public interface instance methods
677 // Not private methods, not static methods, not default == concrete abstract
678 // Miranda methods also do not include overpass methods in interfaces
679 bool klassVtable::is_miranda(Method* m, Array<Method*>* class_methods,
680 Array<Method*>* default_methods, Klass* super) {
681 if (m->is_static() || m->is_private() || m->is_overpass()) {
682 return false;
683 }
684 Symbol* name = m->name();
685 Symbol* signature = m->signature();
687 if (InstanceKlass::find_instance_method(class_methods, name, signature) == NULL) {
688 // did not find it in the method table of the current class
689 if ((default_methods == NULL) ||
690 InstanceKlass::find_method(default_methods, name, signature) == NULL) {
691 if (super == NULL) {
692 // super doesn't exist
693 return true;
694 }
696 Method* mo = InstanceKlass::cast(super)->lookup_method(name, signature);
697 while (mo != NULL && mo->access_flags().is_static()
698 && mo->method_holder() != NULL
699 && mo->method_holder()->super() != NULL)
700 {
701 mo = mo->method_holder()->super()->uncached_lookup_method(name, signature);
702 }
703 if (mo == NULL || mo->access_flags().is_private() ) {
704 // super class hierarchy does not implement it or protection is different
705 return true;
706 }
707 }
708 }
710 return false;
711 }
713 // Scans current_interface_methods for miranda methods that do not
714 // already appear in new_mirandas, or default methods, and are also not defined-and-non-private
715 // in super (superclass). These mirandas are added to all_mirandas if it is
716 // not null; in addition, those that are not duplicates of miranda methods
717 // inherited by super from its interfaces are added to new_mirandas.
718 // Thus, new_mirandas will be the set of mirandas that this class introduces,
719 // all_mirandas will be the set of all mirandas applicable to this class
720 // including all defined in superclasses.
721 void klassVtable::add_new_mirandas_to_lists(
722 GrowableArray<Method*>* new_mirandas, GrowableArray<Method*>* all_mirandas,
723 Array<Method*>* current_interface_methods, Array<Method*>* class_methods,
724 Array<Method*>* default_methods, Klass* super) {
726 // iterate thru the current interface's method to see if it a miranda
727 int num_methods = current_interface_methods->length();
728 for (int i = 0; i < num_methods; i++) {
729 Method* im = current_interface_methods->at(i);
730 bool is_duplicate = false;
731 int num_of_current_mirandas = new_mirandas->length();
732 // check for duplicate mirandas in different interfaces we implement
733 for (int j = 0; j < num_of_current_mirandas; j++) {
734 Method* miranda = new_mirandas->at(j);
735 if ((im->name() == miranda->name()) &&
736 (im->signature() == miranda->signature())) {
737 is_duplicate = true;
738 break;
739 }
740 }
742 if (!is_duplicate) { // we don't want duplicate miranda entries in the vtable
743 if (is_miranda(im, class_methods, default_methods, super)) { // is it a miranda at all?
744 InstanceKlass *sk = InstanceKlass::cast(super);
745 // check if it is a duplicate of a super's miranda
746 if (sk->lookup_method_in_all_interfaces(im->name(), im->signature(), false) == NULL) {
747 new_mirandas->append(im);
748 }
749 if (all_mirandas != NULL) {
750 all_mirandas->append(im);
751 }
752 }
753 }
754 }
755 }
757 void klassVtable::get_mirandas(GrowableArray<Method*>* new_mirandas,
758 GrowableArray<Method*>* all_mirandas,
759 Klass* super, Array<Method*>* class_methods,
760 Array<Method*>* default_methods,
761 Array<Klass*>* local_interfaces) {
762 assert((new_mirandas->length() == 0) , "current mirandas must be 0");
764 // iterate thru the local interfaces looking for a miranda
765 int num_local_ifs = local_interfaces->length();
766 for (int i = 0; i < num_local_ifs; i++) {
767 InstanceKlass *ik = InstanceKlass::cast(local_interfaces->at(i));
768 add_new_mirandas_to_lists(new_mirandas, all_mirandas,
769 ik->methods(), class_methods,
770 default_methods, super);
771 // iterate thru each local's super interfaces
772 Array<Klass*>* super_ifs = ik->transitive_interfaces();
773 int num_super_ifs = super_ifs->length();
774 for (int j = 0; j < num_super_ifs; j++) {
775 InstanceKlass *sik = InstanceKlass::cast(super_ifs->at(j));
776 add_new_mirandas_to_lists(new_mirandas, all_mirandas,
777 sik->methods(), class_methods,
778 default_methods, super);
779 }
780 }
781 }
783 // Discover miranda methods ("miranda" = "interface abstract, no binding"),
784 // and append them into the vtable starting at index initialized,
785 // return the new value of initialized.
786 // Miranda methods use vtable entries, but do not get assigned a vtable_index
787 // The vtable_index is discovered by searching from the end of the vtable
788 int klassVtable::fill_in_mirandas(int initialized) {
789 GrowableArray<Method*> mirandas(20);
790 get_mirandas(&mirandas, NULL, ik()->super(), ik()->methods(),
791 ik()->default_methods(), ik()->local_interfaces());
792 for (int i = 0; i < mirandas.length(); i++) {
793 if (PrintVtables && Verbose) {
794 Method* meth = mirandas.at(i);
795 ResourceMark rm(Thread::current());
796 if (meth != NULL) {
797 char* sig = meth->name_and_sig_as_C_string();
798 tty->print("fill in mirandas with %s index %d, flags: ",
799 sig, initialized);
800 meth->access_flags().print_on(tty);
801 if (meth->is_default_method()) {
802 tty->print("default ");
803 }
804 tty->cr();
805 }
806 }
807 put_method_at(mirandas.at(i), initialized);
808 ++initialized;
809 }
810 return initialized;
811 }
813 // Copy this class's vtable to the vtable beginning at start.
814 // Used to copy superclass vtable to prefix of subclass's vtable.
815 void klassVtable::copy_vtable_to(vtableEntry* start) {
816 Copy::disjoint_words((HeapWord*)table(), (HeapWord*)start, _length * vtableEntry::size());
817 }
819 #if INCLUDE_JVMTI
820 bool klassVtable::adjust_default_method(int vtable_index, Method* old_method, Method* new_method) {
821 // If old_method is default, find this vtable index in default_vtable_indices
822 // and replace that method in the _default_methods list
823 bool updated = false;
825 Array<Method*>* default_methods = ik()->default_methods();
826 if (default_methods != NULL) {
827 int len = default_methods->length();
828 for (int idx = 0; idx < len; idx++) {
829 if (vtable_index == ik()->default_vtable_indices()->at(idx)) {
830 if (default_methods->at(idx) == old_method) {
831 default_methods->at_put(idx, new_method);
832 updated = true;
833 }
834 break;
835 }
836 }
837 }
838 return updated;
839 }
840 void klassVtable::adjust_method_entries(Method** old_methods, Method** new_methods,
841 int methods_length, bool * trace_name_printed) {
842 // search the vtable for uses of either obsolete or EMCP methods
843 for (int j = 0; j < methods_length; j++) {
844 Method* old_method = old_methods[j];
845 Method* new_method = new_methods[j];
847 // In the vast majority of cases we could get the vtable index
848 // by using: old_method->vtable_index()
849 // However, there are rare cases, eg. sun.awt.X11.XDecoratedPeer.getX()
850 // in sun.awt.X11.XFramePeer where methods occur more than once in the
851 // vtable, so, alas, we must do an exhaustive search.
852 for (int index = 0; index < length(); index++) {
853 if (unchecked_method_at(index) == old_method) {
854 put_method_at(new_method, index);
855 // For default methods, need to update the _default_methods array
856 // which can only have one method entry for a given signature
857 bool updated_default = false;
858 if (old_method->is_default_method()) {
859 updated_default = adjust_default_method(index, old_method, new_method);
860 }
862 if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
863 if (!(*trace_name_printed)) {
864 // RC_TRACE_MESG macro has an embedded ResourceMark
865 RC_TRACE_MESG(("adjust: klassname=%s for methods from name=%s",
866 klass()->external_name(),
867 old_method->method_holder()->external_name()));
868 *trace_name_printed = true;
869 }
870 // RC_TRACE macro has an embedded ResourceMark
871 RC_TRACE(0x00100000, ("vtable method update: %s(%s), updated default = %s",
872 new_method->name()->as_C_string(),
873 new_method->signature()->as_C_string(),
874 updated_default ? "true" : "false"));
875 }
876 // cannot 'break' here; see for-loop comment above.
877 }
878 }
879 }
880 }
882 // a vtable should never contain old or obsolete methods
883 bool klassVtable::check_no_old_or_obsolete_entries() {
884 for (int i = 0; i < length(); i++) {
885 Method* m = unchecked_method_at(i);
886 if (m != NULL &&
887 (NOT_PRODUCT(!m->is_valid() ||) m->is_old() || m->is_obsolete())) {
888 return false;
889 }
890 }
891 return true;
892 }
894 void klassVtable::dump_vtable() {
895 tty->print_cr("vtable dump --");
896 for (int i = 0; i < length(); i++) {
897 Method* m = unchecked_method_at(i);
898 if (m != NULL) {
899 tty->print(" (%5d) ", i);
900 m->access_flags().print_on(tty);
901 if (m->is_default_method()) {
902 tty->print("default ");
903 }
904 if (m->is_overpass()) {
905 tty->print("overpass");
906 }
907 tty->print(" -- ");
908 m->print_name(tty);
909 tty->cr();
910 }
911 }
912 }
913 #endif // INCLUDE_JVMTI
915 // CDS/RedefineClasses support - clear vtables so they can be reinitialized
916 void klassVtable::clear_vtable() {
917 for (int i = 0; i < _length; i++) table()[i].clear();
918 }
920 bool klassVtable::is_initialized() {
921 return _length == 0 || table()[0].method() != NULL;
922 }
924 //-----------------------------------------------------------------------------------------
925 // Itable code
927 // Initialize a itableMethodEntry
928 void itableMethodEntry::initialize(Method* m) {
929 if (m == NULL) return;
931 _method = m;
932 }
934 klassItable::klassItable(instanceKlassHandle klass) {
935 _klass = klass;
937 if (klass->itable_length() > 0) {
938 itableOffsetEntry* offset_entry = (itableOffsetEntry*)klass->start_of_itable();
939 if (offset_entry != NULL && offset_entry->interface_klass() != NULL) { // Check that itable is initialized
940 // First offset entry points to the first method_entry
941 intptr_t* method_entry = (intptr_t *)(((address)klass()) + offset_entry->offset());
942 intptr_t* end = klass->end_of_itable();
944 _table_offset = (intptr_t*)offset_entry - (intptr_t*)klass();
945 _size_offset_table = (method_entry - ((intptr_t*)offset_entry)) / itableOffsetEntry::size();
946 _size_method_table = (end - method_entry) / itableMethodEntry::size();
947 assert(_table_offset >= 0 && _size_offset_table >= 0 && _size_method_table >= 0, "wrong computation");
948 return;
949 }
950 }
952 // The length of the itable was either zero, or it has not yet been initialized.
953 _table_offset = 0;
954 _size_offset_table = 0;
955 _size_method_table = 0;
956 }
958 static int initialize_count = 0;
960 // Initialization
961 void klassItable::initialize_itable(bool checkconstraints, TRAPS) {
962 if (_klass->is_interface()) {
963 // This needs to go after vtable indices are assigned but
964 // before implementors need to know the number of itable indices.
965 assign_itable_indices_for_interface(_klass());
966 }
968 // Cannot be setup doing bootstrapping, interfaces don't have
969 // itables, and klass with only ones entry have empty itables
970 if (Universe::is_bootstrapping() ||
971 _klass->is_interface() ||
972 _klass->itable_length() == itableOffsetEntry::size()) return;
974 // There's alway an extra itable entry so we can null-terminate it.
975 guarantee(size_offset_table() >= 1, "too small");
976 int num_interfaces = size_offset_table() - 1;
977 if (num_interfaces > 0) {
978 if (TraceItables) tty->print_cr("%3d: Initializing itables for %s", ++initialize_count,
979 _klass->name()->as_C_string());
982 // Iterate through all interfaces
983 int i;
984 for(i = 0; i < num_interfaces; i++) {
985 itableOffsetEntry* ioe = offset_entry(i);
986 HandleMark hm(THREAD);
987 KlassHandle interf_h (THREAD, ioe->interface_klass());
988 assert(interf_h() != NULL && ioe->offset() != 0, "bad offset entry in itable");
989 initialize_itable_for_interface(ioe->offset(), interf_h, checkconstraints, CHECK);
990 }
992 }
993 // Check that the last entry is empty
994 itableOffsetEntry* ioe = offset_entry(size_offset_table() - 1);
995 guarantee(ioe->interface_klass() == NULL && ioe->offset() == 0, "terminator entry missing");
996 }
999 inline bool interface_method_needs_itable_index(Method* m) {
1000 if (m->is_static()) return false; // e.g., Stream.empty
1001 if (m->is_initializer()) return false; // <init> or <clinit>
1002 // If an interface redeclares a method from java.lang.Object,
1003 // it should already have a vtable index, don't touch it.
1004 // e.g., CharSequence.toString (from initialize_vtable)
1005 // if (m->has_vtable_index()) return false; // NO!
1006 return true;
1007 }
1009 int klassItable::assign_itable_indices_for_interface(Klass* klass) {
1010 // an interface does not have an itable, but its methods need to be numbered
1011 if (TraceItables) tty->print_cr("%3d: Initializing itable for interface %s", ++initialize_count,
1012 klass->name()->as_C_string());
1013 Array<Method*>* methods = InstanceKlass::cast(klass)->methods();
1014 int nof_methods = methods->length();
1015 int ime_num = 0;
1016 for (int i = 0; i < nof_methods; i++) {
1017 Method* m = methods->at(i);
1018 if (interface_method_needs_itable_index(m)) {
1019 assert(!m->is_final_method(), "no final interface methods");
1020 // If m is already assigned a vtable index, do not disturb it.
1021 if (TraceItables && Verbose) {
1022 ResourceMark rm;
1023 const char* sig = (m != NULL) ? m->name_and_sig_as_C_string() : "<NULL>";
1024 if (m->has_vtable_index()) {
1025 tty->print("itable index %d for method: %s, flags: ", m->vtable_index(), sig);
1026 } else {
1027 tty->print("itable index %d for method: %s, flags: ", ime_num, sig);
1028 }
1029 if (m != NULL) {
1030 m->access_flags().print_on(tty);
1031 if (m->is_default_method()) {
1032 tty->print("default ");
1033 }
1034 if (m->is_overpass()) {
1035 tty->print("overpass");
1036 }
1037 }
1038 tty->cr();
1039 }
1040 if (!m->has_vtable_index()) {
1041 assert(m->vtable_index() == Method::pending_itable_index, "set by initialize_vtable");
1042 m->set_itable_index(ime_num);
1043 // Progress to next itable entry
1044 ime_num++;
1045 }
1046 }
1047 }
1048 assert(ime_num == method_count_for_interface(klass), "proper sizing");
1049 return ime_num;
1050 }
1052 int klassItable::method_count_for_interface(Klass* interf) {
1053 assert(interf->oop_is_instance(), "must be");
1054 assert(interf->is_interface(), "must be");
1055 Array<Method*>* methods = InstanceKlass::cast(interf)->methods();
1056 int nof_methods = methods->length();
1057 while (nof_methods > 0) {
1058 Method* m = methods->at(nof_methods-1);
1059 if (m->has_itable_index()) {
1060 int length = m->itable_index() + 1;
1061 #ifdef ASSERT
1062 while (nof_methods = 0) {
1063 m = methods->at(--nof_methods);
1064 assert(!m->has_itable_index() || m->itable_index() < length, "");
1065 }
1066 #endif //ASSERT
1067 return length; // return the rightmost itable index, plus one
1068 }
1069 nof_methods -= 1;
1070 }
1071 // no methods have itable indices
1072 return 0;
1073 }
1076 void klassItable::initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS) {
1077 Array<Method*>* methods = InstanceKlass::cast(interf_h())->methods();
1078 int nof_methods = methods->length();
1079 HandleMark hm;
1080 assert(nof_methods > 0, "at least one method must exist for interface to be in vtable");
1081 Handle interface_loader (THREAD, InstanceKlass::cast(interf_h())->class_loader());
1083 int ime_count = method_count_for_interface(interf_h());
1084 for (int i = 0; i < nof_methods; i++) {
1085 Method* m = methods->at(i);
1086 methodHandle target;
1087 if (m->has_itable_index()) {
1088 // This search must match the runtime resolution, i.e. selection search for invokeinterface
1089 // to correctly enforce loader constraints for interface method inheritance
1090 LinkResolver::lookup_instance_method_in_klasses(target, _klass, m->name(), m->signature(), CHECK);
1091 }
1092 if (target == NULL || !target->is_public() || target->is_abstract()) {
1093 // Entry does not resolve. Leave it empty for AbstractMethodError.
1094 if (!(target == NULL) && !target->is_public()) {
1095 // Stuff an IllegalAccessError throwing method in there instead.
1096 itableOffsetEntry::method_entry(_klass(), method_table_offset)[m->itable_index()].
1097 initialize(Universe::throw_illegal_access_error());
1098 }
1099 } else {
1100 // Entry did resolve, check loader constraints before initializing
1101 // if checkconstraints requested
1102 if (checkconstraints) {
1103 Handle method_holder_loader (THREAD, target->method_holder()->class_loader());
1104 if (method_holder_loader() != interface_loader()) {
1105 ResourceMark rm(THREAD);
1106 Symbol* failed_type_symbol =
1107 SystemDictionary::check_signature_loaders(m->signature(),
1108 method_holder_loader,
1109 interface_loader,
1110 true, CHECK);
1111 if (failed_type_symbol != NULL) {
1112 const char* msg = "loader constraint violation in interface "
1113 "itable initialization: when resolving method \"%s\" the class"
1114 " loader (instance of %s) of the current class, %s, "
1115 "and the class loader (instance of %s) for interface "
1116 "%s have different Class objects for the type %s "
1117 "used in the signature";
1118 char* sig = target()->name_and_sig_as_C_string();
1119 const char* loader1 = SystemDictionary::loader_name(method_holder_loader());
1120 char* current = _klass->name()->as_C_string();
1121 const char* loader2 = SystemDictionary::loader_name(interface_loader());
1122 char* iface = InstanceKlass::cast(interf_h())->name()->as_C_string();
1123 char* failed_type_name = failed_type_symbol->as_C_string();
1124 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
1125 strlen(current) + strlen(loader2) + strlen(iface) +
1126 strlen(failed_type_name);
1127 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
1128 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2,
1129 iface, failed_type_name);
1130 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
1131 }
1132 }
1133 }
1135 // ime may have moved during GC so recalculate address
1136 int ime_num = m->itable_index();
1137 assert(ime_num < ime_count, "oob");
1138 itableOffsetEntry::method_entry(_klass(), method_table_offset)[ime_num].initialize(target());
1139 if (TraceItables && Verbose) {
1140 ResourceMark rm(THREAD);
1141 if (target() != NULL) {
1142 char* sig = target()->name_and_sig_as_C_string();
1143 tty->print("interface: %s, ime_num: %d, target: %s, method_holder: %s ",
1144 interf_h()->internal_name(), ime_num, sig,
1145 target()->method_holder()->internal_name());
1146 tty->print("target_method flags: ");
1147 target()->access_flags().print_on(tty);
1148 if (target()->is_default_method()) {
1149 tty->print("default ");
1150 }
1151 tty->cr();
1152 }
1153 }
1154 }
1155 }
1156 }
1158 // Update entry for specific Method*
1159 void klassItable::initialize_with_method(Method* m) {
1160 itableMethodEntry* ime = method_entry(0);
1161 for(int i = 0; i < _size_method_table; i++) {
1162 if (ime->method() == m) {
1163 ime->initialize(m);
1164 }
1165 ime++;
1166 }
1167 }
1169 #if INCLUDE_JVMTI
1170 void klassItable::adjust_method_entries(Method** old_methods, Method** new_methods,
1171 int methods_length, bool * trace_name_printed) {
1172 // search the itable for uses of either obsolete or EMCP methods
1173 for (int j = 0; j < methods_length; j++) {
1174 Method* old_method = old_methods[j];
1175 Method* new_method = new_methods[j];
1176 itableMethodEntry* ime = method_entry(0);
1178 // The itable can describe more than one interface and the same
1179 // method signature can be specified by more than one interface.
1180 // This means we have to do an exhaustive search to find all the
1181 // old_method references.
1182 for (int i = 0; i < _size_method_table; i++) {
1183 if (ime->method() == old_method) {
1184 ime->initialize(new_method);
1186 if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
1187 if (!(*trace_name_printed)) {
1188 // RC_TRACE_MESG macro has an embedded ResourceMark
1189 RC_TRACE_MESG(("adjust: name=%s",
1190 old_method->method_holder()->external_name()));
1191 *trace_name_printed = true;
1192 }
1193 // RC_TRACE macro has an embedded ResourceMark
1194 RC_TRACE(0x00200000, ("itable method update: %s(%s)",
1195 new_method->name()->as_C_string(),
1196 new_method->signature()->as_C_string()));
1197 }
1198 // cannot 'break' here; see for-loop comment above.
1199 }
1200 ime++;
1201 }
1202 }
1203 }
1205 // an itable should never contain old or obsolete methods
1206 bool klassItable::check_no_old_or_obsolete_entries() {
1207 itableMethodEntry* ime = method_entry(0);
1208 for (int i = 0; i < _size_method_table; i++) {
1209 Method* m = ime->method();
1210 if (m != NULL &&
1211 (NOT_PRODUCT(!m->is_valid() ||) m->is_old() || m->is_obsolete())) {
1212 return false;
1213 }
1214 ime++;
1215 }
1216 return true;
1217 }
1219 void klassItable::dump_itable() {
1220 itableMethodEntry* ime = method_entry(0);
1221 tty->print_cr("itable dump --");
1222 for (int i = 0; i < _size_method_table; i++) {
1223 Method* m = ime->method();
1224 if (m != NULL) {
1225 tty->print(" (%5d) ", i);
1226 m->access_flags().print_on(tty);
1227 if (m->is_default_method()) {
1228 tty->print("default ");
1229 }
1230 tty->print(" -- ");
1231 m->print_name(tty);
1232 tty->cr();
1233 }
1234 ime++;
1235 }
1236 }
1237 #endif // INCLUDE_JVMTI
1240 // Setup
1241 class InterfaceVisiterClosure : public StackObj {
1242 public:
1243 virtual void doit(Klass* intf, int method_count) = 0;
1244 };
1246 // Visit all interfaces with at least one itable method
1247 void visit_all_interfaces(Array<Klass*>* transitive_intf, InterfaceVisiterClosure *blk) {
1248 // Handle array argument
1249 for(int i = 0; i < transitive_intf->length(); i++) {
1250 Klass* intf = transitive_intf->at(i);
1251 assert(intf->is_interface(), "sanity check");
1253 // Find no. of itable methods
1254 int method_count = 0;
1255 // method_count = klassItable::method_count_for_interface(intf);
1256 Array<Method*>* methods = InstanceKlass::cast(intf)->methods();
1257 if (methods->length() > 0) {
1258 for (int i = methods->length(); --i >= 0; ) {
1259 if (interface_method_needs_itable_index(methods->at(i))) {
1260 method_count++;
1261 }
1262 }
1263 }
1265 // Only count interfaces with at least one method
1266 if (method_count > 0) {
1267 blk->doit(intf, method_count);
1268 }
1269 }
1270 }
1272 class CountInterfacesClosure : public InterfaceVisiterClosure {
1273 private:
1274 int _nof_methods;
1275 int _nof_interfaces;
1276 public:
1277 CountInterfacesClosure() { _nof_methods = 0; _nof_interfaces = 0; }
1279 int nof_methods() const { return _nof_methods; }
1280 int nof_interfaces() const { return _nof_interfaces; }
1282 void doit(Klass* intf, int method_count) { _nof_methods += method_count; _nof_interfaces++; }
1283 };
1285 class SetupItableClosure : public InterfaceVisiterClosure {
1286 private:
1287 itableOffsetEntry* _offset_entry;
1288 itableMethodEntry* _method_entry;
1289 address _klass_begin;
1290 public:
1291 SetupItableClosure(address klass_begin, itableOffsetEntry* offset_entry, itableMethodEntry* method_entry) {
1292 _klass_begin = klass_begin;
1293 _offset_entry = offset_entry;
1294 _method_entry = method_entry;
1295 }
1297 itableMethodEntry* method_entry() const { return _method_entry; }
1299 void doit(Klass* intf, int method_count) {
1300 int offset = ((address)_method_entry) - _klass_begin;
1301 _offset_entry->initialize(intf, offset);
1302 _offset_entry++;
1303 _method_entry += method_count;
1304 }
1305 };
1307 int klassItable::compute_itable_size(Array<Klass*>* transitive_interfaces) {
1308 // Count no of interfaces and total number of interface methods
1309 CountInterfacesClosure cic;
1310 visit_all_interfaces(transitive_interfaces, &cic);
1312 // There's alway an extra itable entry so we can null-terminate it.
1313 int itable_size = calc_itable_size(cic.nof_interfaces() + 1, cic.nof_methods());
1315 // Statistics
1316 update_stats(itable_size * HeapWordSize);
1318 return itable_size;
1319 }
1322 // Fill out offset table and interface klasses into the itable space
1323 void klassItable::setup_itable_offset_table(instanceKlassHandle klass) {
1324 if (klass->itable_length() == 0) return;
1325 assert(!klass->is_interface(), "Should have zero length itable");
1327 // Count no of interfaces and total number of interface methods
1328 CountInterfacesClosure cic;
1329 visit_all_interfaces(klass->transitive_interfaces(), &cic);
1330 int nof_methods = cic.nof_methods();
1331 int nof_interfaces = cic.nof_interfaces();
1333 // Add one extra entry so we can null-terminate the table
1334 nof_interfaces++;
1336 assert(compute_itable_size(klass->transitive_interfaces()) ==
1337 calc_itable_size(nof_interfaces, nof_methods),
1338 "mismatch calculation of itable size");
1340 // Fill-out offset table
1341 itableOffsetEntry* ioe = (itableOffsetEntry*)klass->start_of_itable();
1342 itableMethodEntry* ime = (itableMethodEntry*)(ioe + nof_interfaces);
1343 intptr_t* end = klass->end_of_itable();
1344 assert((oop*)(ime + nof_methods) <= (oop*)klass->start_of_nonstatic_oop_maps(), "wrong offset calculation (1)");
1345 assert((oop*)(end) == (oop*)(ime + nof_methods), "wrong offset calculation (2)");
1347 // Visit all interfaces and initialize itable offset table
1348 SetupItableClosure sic((address)klass(), ioe, ime);
1349 visit_all_interfaces(klass->transitive_interfaces(), &sic);
1351 #ifdef ASSERT
1352 ime = sic.method_entry();
1353 oop* v = (oop*) klass->end_of_itable();
1354 assert( (oop*)(ime) == v, "wrong offset calculation (2)");
1355 #endif
1356 }
1359 // inverse to itable_index
1360 Method* klassItable::method_for_itable_index(Klass* intf, int itable_index) {
1361 assert(InstanceKlass::cast(intf)->is_interface(), "sanity check");
1362 assert(intf->verify_itable_index(itable_index), "");
1363 Array<Method*>* methods = InstanceKlass::cast(intf)->methods();
1365 if (itable_index < 0 || itable_index >= method_count_for_interface(intf))
1366 return NULL; // help caller defend against bad indices
1368 int index = itable_index;
1369 Method* m = methods->at(index);
1370 int index2 = -1;
1371 while (!m->has_itable_index() ||
1372 (index2 = m->itable_index()) != itable_index) {
1373 assert(index2 < itable_index, "monotonic");
1374 if (++index == methods->length())
1375 return NULL;
1376 m = methods->at(index);
1377 }
1378 assert(m->itable_index() == itable_index, "correct inverse");
1380 return m;
1381 }
1383 void klassVtable::verify(outputStream* st, bool forced) {
1384 // make sure table is initialized
1385 if (!Universe::is_fully_initialized()) return;
1386 #ifndef PRODUCT
1387 // avoid redundant verifies
1388 if (!forced && _verify_count == Universe::verify_count()) return;
1389 _verify_count = Universe::verify_count();
1390 #endif
1391 oop* end_of_obj = (oop*)_klass() + _klass()->size();
1392 oop* end_of_vtable = (oop *)&table()[_length];
1393 if (end_of_vtable > end_of_obj) {
1394 fatal(err_msg("klass %s: klass object too short (vtable extends beyond "
1395 "end)", _klass->internal_name()));
1396 }
1398 for (int i = 0; i < _length; i++) table()[i].verify(this, st);
1399 // verify consistency with superKlass vtable
1400 Klass* super = _klass->super();
1401 if (super != NULL) {
1402 InstanceKlass* sk = InstanceKlass::cast(super);
1403 klassVtable* vt = sk->vtable();
1404 for (int i = 0; i < vt->length(); i++) {
1405 verify_against(st, vt, i);
1406 }
1407 }
1408 }
1410 void klassVtable::verify_against(outputStream* st, klassVtable* vt, int index) {
1411 vtableEntry* vte = &vt->table()[index];
1412 if (vte->method()->name() != table()[index].method()->name() ||
1413 vte->method()->signature() != table()[index].method()->signature()) {
1414 fatal("mismatched name/signature of vtable entries");
1415 }
1416 }
1418 #ifndef PRODUCT
1419 void klassVtable::print() {
1420 ResourceMark rm;
1421 tty->print("klassVtable for klass %s (length %d):\n", _klass->internal_name(), length());
1422 for (int i = 0; i < length(); i++) {
1423 table()[i].print();
1424 tty->cr();
1425 }
1426 }
1427 #endif
1429 void vtableEntry::verify(klassVtable* vt, outputStream* st) {
1430 NOT_PRODUCT(FlagSetting fs(IgnoreLockingAssertions, true));
1431 assert(method() != NULL, "must have set method");
1432 method()->verify();
1433 // we sub_type, because it could be a miranda method
1434 if (!vt->klass()->is_subtype_of(method()->method_holder())) {
1435 #ifndef PRODUCT
1436 print();
1437 #endif
1438 fatal(err_msg("vtableEntry " PTR_FORMAT ": method is from subclass", this));
1439 }
1440 }
1442 #ifndef PRODUCT
1444 void vtableEntry::print() {
1445 ResourceMark rm;
1446 tty->print("vtableEntry %s: ", method()->name()->as_C_string());
1447 if (Verbose) {
1448 tty->print("m %#lx ", (address)method());
1449 }
1450 }
1452 class VtableStats : AllStatic {
1453 public:
1454 static int no_klasses; // # classes with vtables
1455 static int no_array_klasses; // # array classes
1456 static int no_instance_klasses; // # instanceKlasses
1457 static int sum_of_vtable_len; // total # of vtable entries
1458 static int sum_of_array_vtable_len; // total # of vtable entries in array klasses only
1459 static int fixed; // total fixed overhead in bytes
1460 static int filler; // overhead caused by filler bytes
1461 static int entries; // total bytes consumed by vtable entries
1462 static int array_entries; // total bytes consumed by array vtable entries
1464 static void do_class(Klass* k) {
1465 Klass* kl = k;
1466 klassVtable* vt = kl->vtable();
1467 if (vt == NULL) return;
1468 no_klasses++;
1469 if (kl->oop_is_instance()) {
1470 no_instance_klasses++;
1471 kl->array_klasses_do(do_class);
1472 }
1473 if (kl->oop_is_array()) {
1474 no_array_klasses++;
1475 sum_of_array_vtable_len += vt->length();
1476 }
1477 sum_of_vtable_len += vt->length();
1478 }
1480 static void compute() {
1481 SystemDictionary::classes_do(do_class);
1482 fixed = no_klasses * oopSize; // vtable length
1483 // filler size is a conservative approximation
1484 filler = oopSize * (no_klasses - no_instance_klasses) * (sizeof(InstanceKlass) - sizeof(ArrayKlass) - 1);
1485 entries = sizeof(vtableEntry) * sum_of_vtable_len;
1486 array_entries = sizeof(vtableEntry) * sum_of_array_vtable_len;
1487 }
1488 };
1490 int VtableStats::no_klasses = 0;
1491 int VtableStats::no_array_klasses = 0;
1492 int VtableStats::no_instance_klasses = 0;
1493 int VtableStats::sum_of_vtable_len = 0;
1494 int VtableStats::sum_of_array_vtable_len = 0;
1495 int VtableStats::fixed = 0;
1496 int VtableStats::filler = 0;
1497 int VtableStats::entries = 0;
1498 int VtableStats::array_entries = 0;
1500 void klassVtable::print_statistics() {
1501 ResourceMark rm;
1502 HandleMark hm;
1503 VtableStats::compute();
1504 tty->print_cr("vtable statistics:");
1505 tty->print_cr("%6d classes (%d instance, %d array)", VtableStats::no_klasses, VtableStats::no_instance_klasses, VtableStats::no_array_klasses);
1506 int total = VtableStats::fixed + VtableStats::filler + VtableStats::entries;
1507 tty->print_cr("%6d bytes fixed overhead (refs + vtable object header)", VtableStats::fixed);
1508 tty->print_cr("%6d bytes filler overhead", VtableStats::filler);
1509 tty->print_cr("%6d bytes for vtable entries (%d for arrays)", VtableStats::entries, VtableStats::array_entries);
1510 tty->print_cr("%6d bytes total", total);
1511 }
1513 int klassItable::_total_classes; // Total no. of classes with itables
1514 long klassItable::_total_size; // Total no. of bytes used for itables
1516 void klassItable::print_statistics() {
1517 tty->print_cr("itable statistics:");
1518 tty->print_cr("%6d classes with itables", _total_classes);
1519 tty->print_cr("%6d K uses for itables (average by class: %d bytes)", _total_size / K, _total_size / _total_classes);
1520 }
1522 #endif // PRODUCT