1 /* 2 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "classfile/systemDictionary.hpp" 27 #include "classfile/vmSymbols.hpp" 28 #include "gc_implementation/shared/markSweep.inline.hpp" 29 #include "memory/gcLocker.hpp" 30 #include "memory/resourceArea.hpp" 31 #include "memory/universe.inline.hpp" 32 #include "oops/instanceKlass.hpp" 33 #include "oops/klassOop.hpp" 34 #include "oops/klassVtable.hpp" 35 #include "oops/methodOop.hpp" 36 #include "oops/objArrayOop.hpp" 37 #include "oops/oop.inline.hpp" 38 #include "prims/jvmtiRedefineClassesTrace.hpp" 39 #include "runtime/arguments.hpp" 40 #include "runtime/handles.inline.hpp" 41 #include "utilities/copy.hpp" 42 43 inline instanceKlass* klassVtable::ik() const { 44 Klass* k = _klass()->klass_part(); 45 assert(k->oop_is_instance(), "not an instanceKlass"); 46 return (instanceKlass*)k; 47 } 48 49 50 // this function computes the vtable size (including the size needed for miranda 51 // methods) and the number of miranda methods in this class 52 // Note on Miranda methods: Let's say there is a class C that implements 53 // interface I. Let's say there is a method m in I that neither C nor any 54 // of its super classes implement (i.e there is no method of any access, with 55 // 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(int &vtable_length, 59 int &num_miranda_methods, 60 klassOop super, 61 objArrayOop methods, 62 AccessFlags class_flags, 63 Handle classloader, 64 Symbol* classname, 65 objArrayOop local_interfaces, 66 TRAPS 67 ) { 68 69 No_Safepoint_Verifier nsv; 70 71 // set up default result values 72 vtable_length = 0; 73 num_miranda_methods = 0; 74 75 // start off with super's vtable length 76 instanceKlass* sk = (instanceKlass*)super->klass_part(); 77 vtable_length = super == NULL ? 0 : sk->vtable_length(); 78 79 // go thru each method in the methods table to see if it needs a new entry 80 int len = methods->length(); 81 for (int i = 0; i < len; i++) { 82 assert(methods->obj_at(i)->is_method(), "must be a methodOop"); 83 methodHandle mh(THREAD, methodOop(methods->obj_at(i))); 84 85 if (needs_new_vtable_entry(mh, super, classloader, classname, class_flags, THREAD)) { 86 vtable_length += vtableEntry::size(); // we need a new entry 87 } 88 } 89 90 // compute the number of mirandas methods that must be added to the end 91 num_miranda_methods = get_num_mirandas(super, methods, local_interfaces); 92 vtable_length += (num_miranda_methods * vtableEntry::size()); 93 94 if (Universe::is_bootstrapping() && vtable_length == 0) { 95 // array classes don't have their superclass set correctly during 96 // bootstrapping 97 vtable_length = Universe::base_vtable_size(); 98 } 99 100 if (super == NULL && !Universe::is_bootstrapping() && 101 vtable_length != Universe::base_vtable_size()) { 102 // Someone is attempting to redefine java.lang.Object incorrectly. The 103 // only way this should happen is from 104 // SystemDictionary::resolve_from_stream(), which will detect this later 105 // and throw a security exception. So don't assert here to let 106 // the exception occur. 107 vtable_length = Universe::base_vtable_size(); 108 } 109 assert(super != NULL || vtable_length == Universe::base_vtable_size(), 110 "bad vtable size for class Object"); 111 assert(vtable_length % vtableEntry::size() == 0, "bad vtable length"); 112 assert(vtable_length >= Universe::base_vtable_size(), "vtable too small"); 113 } 114 115 int klassVtable::index_of(methodOop m, int len) const { 116 assert(m->vtable_index() >= 0, "do not ask this of non-vtable methods"); 117 return m->vtable_index(); 118 } 119 120 int klassVtable::initialize_from_super(KlassHandle super) { 121 if (super.is_null()) { 122 return 0; 123 } else { 124 // copy methods from superKlass 125 // can't inherit from array class, so must be instanceKlass 126 assert(super->oop_is_instance(), "must be instance klass"); 127 instanceKlass* sk = (instanceKlass*)super()->klass_part(); 128 klassVtable* superVtable = sk->vtable(); 129 assert(superVtable->length() <= _length, "vtable too short"); 130 #ifdef ASSERT 131 superVtable->verify(tty, true); 132 #endif 133 superVtable->copy_vtable_to(table()); 134 #ifndef PRODUCT 135 if (PrintVtables && Verbose) { 136 ResourceMark rm; 137 tty->print_cr("copy vtable from %s to %s size %d", sk->internal_name(), klass()->internal_name(), _length); 138 } 139 #endif 140 return superVtable->length(); 141 } 142 } 143 144 // Revised lookup semantics introduced 1.3 (Kestral beta) 145 void klassVtable::initialize_vtable(bool checkconstraints, TRAPS) { 146 147 // Note: Arrays can have intermediate array supers. Use java_super to skip them. 148 KlassHandle super (THREAD, klass()->java_super()); 149 int nofNewEntries = 0; 150 151 152 if (PrintVtables && !klass()->oop_is_array()) { 153 ResourceMark rm(THREAD); 154 tty->print_cr("Initializing: %s", _klass->name()->as_C_string()); 155 } 156 157 #ifdef ASSERT 158 oop* end_of_obj = (oop*)_klass() + _klass()->size(); 159 oop* end_of_vtable = (oop*)&table()[_length]; 160 assert(end_of_vtable <= end_of_obj, "vtable extends beyond end"); 161 #endif 162 163 if (Universe::is_bootstrapping()) { 164 // just clear everything 165 for (int i = 0; i < _length; i++) table()[i].clear(); 166 return; 167 } 168 169 int super_vtable_len = initialize_from_super(super); 170 if (klass()->oop_is_array()) { 171 assert(super_vtable_len == _length, "arrays shouldn't introduce new methods"); 172 } else { 173 assert(_klass->oop_is_instance(), "must be instanceKlass"); 174 175 objArrayHandle methods(THREAD, ik()->methods()); 176 int len = methods()->length(); 177 int initialized = super_vtable_len; 178 179 // update_inherited_vtable can stop for gc - ensure using handles 180 for (int i = 0; i < len; i++) { 181 HandleMark hm(THREAD); 182 assert(methods()->obj_at(i)->is_method(), "must be a methodOop"); 183 methodHandle mh(THREAD, (methodOop)methods()->obj_at(i)); 184 185 bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, checkconstraints, CHECK); 186 187 if (needs_new_entry) { 188 put_method_at(mh(), initialized); 189 mh()->set_vtable_index(initialized); // set primary vtable index 190 initialized++; 191 } 192 } 193 194 // add miranda methods; it will also update the value of initialized 195 fill_in_mirandas(initialized); 196 197 // In class hierarchies where the accessibility is not increasing (i.e., going from private -> 198 // package_private -> publicprotected), the vtable might actually be smaller than our initial 199 // calculation. 200 assert(initialized <= _length, "vtable initialization failed"); 201 for(;initialized < _length; initialized++) { 202 put_method_at(NULL, initialized); 203 } 204 NOT_PRODUCT(verify(tty, true)); 205 } 206 } 207 208 // Called for cases where a method does not override its superclass' vtable entry 209 // For bytecodes not produced by javac together it is possible that a method does not override 210 // the superclass's method, but might indirectly override a super-super class's vtable entry 211 // If none found, return a null superk, else return the superk of the method this does override 212 instanceKlass* klassVtable::find_transitive_override(instanceKlass* initialsuper, methodHandle target_method, 213 int vtable_index, Handle target_loader, Symbol* target_classname, Thread * THREAD) { 214 instanceKlass* superk = initialsuper; 215 while (superk != NULL && superk->super() != NULL) { 216 instanceKlass* supersuperklass = instanceKlass::cast(superk->super()); 217 klassVtable* ssVtable = supersuperklass->vtable(); 218 if (vtable_index < ssVtable->length()) { 219 methodOop super_method = ssVtable->method_at(vtable_index); 220 #ifndef PRODUCT 221 Symbol* name= target_method()->name(); 222 Symbol* signature = target_method()->signature(); 223 assert(super_method->name() == name && super_method->signature() == signature, "vtable entry name/sig mismatch"); 224 #endif 225 if (supersuperklass->is_override(super_method, target_loader, target_classname, THREAD)) { 226 #ifndef PRODUCT 227 if (PrintVtables && Verbose) { 228 ResourceMark rm(THREAD); 229 tty->print("transitive overriding superclass %s with %s::%s index %d, original flags: ", 230 supersuperklass->internal_name(), 231 _klass->internal_name(), (target_method() != NULL) ? 232 target_method()->name()->as_C_string() : "<NULL>", vtable_index); 233 super_method->access_flags().print_on(tty); 234 tty->print("overriders flags: "); 235 target_method->access_flags().print_on(tty); 236 tty->cr(); 237 } 238 #endif /*PRODUCT*/ 239 break; // return found superk 240 } 241 } else { 242 // super class has no vtable entry here, stop transitive search 243 superk = (instanceKlass*)NULL; 244 break; 245 } 246 // if no override found yet, continue to search up 247 superk = instanceKlass::cast(superk->super()); 248 } 249 250 return superk; 251 } 252 253 254 // Update child's copy of super vtable for overrides 255 // OR return true if a new vtable entry is required 256 // Only called for instanceKlass's, i.e. not for arrays 257 // If that changed, could not use _klass as handle for klass 258 bool klassVtable::update_inherited_vtable(instanceKlass* klass, methodHandle target_method, int super_vtable_len, 259 bool checkconstraints, TRAPS) { 260 ResourceMark rm; 261 bool allocate_new = true; 262 assert(klass->oop_is_instance(), "must be instanceKlass"); 263 264 // Initialize the method's vtable index to "nonvirtual". 265 // If we allocate a vtable entry, we will update it to a non-negative number. 266 target_method()->set_vtable_index(methodOopDesc::nonvirtual_vtable_index); 267 268 // Static and <init> methods are never in 269 if (target_method()->is_static() || target_method()->name() == vmSymbols::object_initializer_name()) { 270 return false; 271 } 272 273 if (klass->is_final() || target_method()->is_final()) { 274 // a final method never needs a new entry; final methods can be statically 275 // resolved and they have to be present in the vtable only if they override 276 // a super's method, in which case they re-use its entry 277 allocate_new = false; 278 } 279 280 // we need a new entry if there is no superclass 281 if (klass->super() == NULL) { 282 return allocate_new; 283 } 284 285 // private methods always have a new entry in the vtable 286 // specification interpretation since classic has 287 // private methods not overriding 288 if (target_method()->is_private()) { 289 return allocate_new; 290 } 291 292 // search through the vtable and update overridden entries 293 // Since check_signature_loaders acquires SystemDictionary_lock 294 // which can block for gc, once we are in this loop, use handles 295 // For classfiles built with >= jdk7, we now look for transitive overrides 296 297 Symbol* name = target_method()->name(); 298 Symbol* signature = target_method()->signature(); 299 Handle target_loader(THREAD, _klass->class_loader()); 300 Symbol* target_classname = _klass->name(); 301 for(int i = 0; i < super_vtable_len; i++) { 302 methodOop super_method = method_at(i); 303 // Check if method name matches 304 if (super_method->name() == name && super_method->signature() == signature) { 305 306 // get super_klass for method_holder for the found method 307 instanceKlass* super_klass = instanceKlass::cast(super_method->method_holder()); 308 309 if ((super_klass->is_override(super_method, target_loader, target_classname, THREAD)) || 310 ((klass->major_version() >= VTABLE_TRANSITIVE_OVERRIDE_VERSION) 311 && ((super_klass = find_transitive_override(super_klass, target_method, i, target_loader, 312 target_classname, THREAD)) != (instanceKlass*)NULL))) { 313 // overriding, so no new entry 314 allocate_new = false; 315 316 if (checkconstraints) { 317 // Override vtable entry if passes loader constraint check 318 // if loader constraint checking requested 319 // No need to visit his super, since he and his super 320 // have already made any needed loader constraints. 321 // Since loader constraints are transitive, it is enough 322 // to link to the first super, and we get all the others. 323 Handle super_loader(THREAD, super_klass->class_loader()); 324 325 if (target_loader() != super_loader()) { 326 ResourceMark rm(THREAD); 327 char* failed_type_name = 328 SystemDictionary::check_signature_loaders(signature, target_loader, 329 super_loader, true, 330 CHECK_(false)); 331 if (failed_type_name != NULL) { 332 const char* msg = "loader constraint violation: when resolving " 333 "overridden method \"%s\" the class loader (instance" 334 " of %s) of the current class, %s, and its superclass loader " 335 "(instance of %s), have different Class objects for the type " 336 "%s used in the signature"; 337 char* sig = target_method()->name_and_sig_as_C_string(); 338 const char* loader1 = SystemDictionary::loader_name(target_loader()); 339 char* current = _klass->name()->as_C_string(); 340 const char* loader2 = SystemDictionary::loader_name(super_loader()); 341 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) + 342 strlen(current) + strlen(loader2) + strlen(failed_type_name); 343 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen); 344 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2, 345 failed_type_name); 346 THROW_MSG_(vmSymbols::java_lang_LinkageError(), buf, false); 347 } 348 } 349 } 350 351 put_method_at(target_method(), i); 352 target_method()->set_vtable_index(i); 353 #ifndef PRODUCT 354 if (PrintVtables && Verbose) { 355 tty->print("overriding with %s::%s index %d, original flags: ", 356 _klass->internal_name(), (target_method() != NULL) ? 357 target_method()->name()->as_C_string() : "<NULL>", i); 358 super_method->access_flags().print_on(tty); 359 tty->print("overriders flags: "); 360 target_method->access_flags().print_on(tty); 361 tty->cr(); 362 } 363 #endif /*PRODUCT*/ 364 } else { 365 // allocate_new = true; default. We might override one entry, 366 // but not override another. Once we override one, not need new 367 #ifndef PRODUCT 368 if (PrintVtables && Verbose) { 369 tty->print("NOT overriding with %s::%s index %d, original flags: ", 370 _klass->internal_name(), (target_method() != NULL) ? 371 target_method()->name()->as_C_string() : "<NULL>", i); 372 super_method->access_flags().print_on(tty); 373 tty->print("overriders flags: "); 374 target_method->access_flags().print_on(tty); 375 tty->cr(); 376 } 377 #endif /*PRODUCT*/ 378 } 379 } 380 } 381 return allocate_new; 382 } 383 384 void klassVtable::put_method_at(methodOop m, int index) { 385 assert(m->is_oop_or_null(), "Not an oop or null"); 386 #ifndef PRODUCT 387 if (PrintVtables && Verbose) { 388 ResourceMark rm; 389 tty->print_cr("adding %s::%s at index %d", _klass->internal_name(), 390 (m != NULL) ? m->name()->as_C_string() : "<NULL>", index); 391 } 392 assert(unchecked_method_at(index)->is_oop_or_null(), "Not an oop or null"); 393 #endif 394 table()[index].set(m); 395 } 396 397 // Find out if a method "m" with superclass "super", loader "classloader" and 398 // name "classname" needs a new vtable entry. Let P be a class package defined 399 // by "classloader" and "classname". 400 // NOTE: The logic used here is very similar to the one used for computing 401 // the vtables indices for a method. We cannot directly use that function because, 402 // we allocate the instanceKlass at load time, and that requires that the 403 // superclass has been loaded. 404 // However, the vtable entries are filled in at link time, and therefore 405 // the superclass' vtable may not yet have been filled in. 406 bool klassVtable::needs_new_vtable_entry(methodHandle target_method, 407 klassOop super, 408 Handle classloader, 409 Symbol* classname, 410 AccessFlags class_flags, 411 TRAPS) { 412 if ((class_flags.is_final() || target_method()->is_final()) || 413 // a final method never needs a new entry; final methods can be statically 414 // resolved and they have to be present in the vtable only if they override 415 // a super's method, in which case they re-use its entry 416 (target_method()->is_static()) || 417 // static methods don't need to be in vtable 418 (target_method()->name() == vmSymbols::object_initializer_name()) 419 // <init> is never called dynamically-bound 420 ) { 421 return false; 422 } 423 424 // we need a new entry if there is no superclass 425 if (super == NULL) { 426 return true; 427 } 428 429 // private methods always have a new entry in the vtable 430 // specification interpretation since classic has 431 // private methods not overriding 432 if (target_method()->is_private()) { 433 return true; 434 } 435 436 // search through the super class hierarchy to see if we need 437 // a new entry 438 ResourceMark rm; 439 Symbol* name = target_method()->name(); 440 Symbol* signature = target_method()->signature(); 441 klassOop k = super; 442 methodOop super_method = NULL; 443 instanceKlass *holder = NULL; 444 methodOop recheck_method = NULL; 445 while (k != NULL) { 446 // lookup through the hierarchy for a method with matching name and sign. 447 super_method = instanceKlass::cast(k)->lookup_method(name, signature); 448 if (super_method == NULL) { 449 break; // we still have to search for a matching miranda method 450 } 451 // get the class holding the matching method 452 // make sure you use that class for is_override 453 instanceKlass* superk = instanceKlass::cast(super_method->method_holder()); 454 // we want only instance method matches 455 // pretend private methods are not in the super vtable 456 // since we do override around them: e.g. a.m pub/b.m private/c.m pub, 457 // ignore private, c.m pub does override a.m pub 458 // For classes that were not javac'd together, we also do transitive overriding around 459 // methods that have less accessibility 460 if ((!super_method->is_static()) && 461 (!super_method->is_private())) { 462 if (superk->is_override(super_method, classloader, classname, THREAD)) { 463 return false; 464 // else keep looking for transitive overrides 465 } 466 } 467 468 // Start with lookup result and continue to search up 469 k = superk->super(); // haven't found an override match yet; continue to look 470 } 471 472 // if the target method is public or protected it may have a matching 473 // miranda method in the super, whose entry it should re-use. 474 // Actually, to handle cases that javac would not generate, we need 475 // this check for all access permissions. 476 instanceKlass *sk = instanceKlass::cast(super); 477 if (sk->has_miranda_methods()) { 478 if (sk->lookup_method_in_all_interfaces(name, signature) != NULL) { 479 return false; // found a matching miranda; we do not need a new entry 480 } 481 } 482 return true; // found no match; we need a new entry 483 } 484 485 // Support for miranda methods 486 487 // get the vtable index of a miranda method with matching "name" and "signature" 488 int klassVtable::index_of_miranda(Symbol* name, Symbol* signature) { 489 // search from the bottom, might be faster 490 for (int i = (length() - 1); i >= 0; i--) { 491 methodOop m = table()[i].method(); 492 if (is_miranda_entry_at(i) && 493 m->name() == name && m->signature() == signature) { 494 return i; 495 } 496 } 497 return methodOopDesc::invalid_vtable_index; 498 } 499 500 // check if an entry is miranda 501 bool klassVtable::is_miranda_entry_at(int i) { 502 methodOop m = method_at(i); 503 klassOop method_holder = m->method_holder(); 504 instanceKlass *mhk = instanceKlass::cast(method_holder); 505 506 // miranda methods are interface methods in a class's vtable 507 if (mhk->is_interface()) { 508 assert(m->is_public() && m->is_abstract(), "should be public and abstract"); 509 assert(ik()->implements_interface(method_holder) , "this class should implement the interface"); 510 assert(is_miranda(m, ik()->methods(), ik()->super()), "should be a miranda_method"); 511 return true; 512 } 513 return false; 514 } 515 516 // check if a method is a miranda method, given a class's methods table and it's super 517 // the caller must make sure that the method belongs to an interface implemented by the class 518 bool klassVtable::is_miranda(methodOop m, objArrayOop class_methods, klassOop super) { 519 Symbol* name = m->name(); 520 Symbol* signature = m->signature(); 521 if (instanceKlass::find_method(class_methods, name, signature) == NULL) { 522 // did not find it in the method table of the current class 523 if (super == NULL) { 524 // super doesn't exist 525 return true; 526 } 527 528 methodOop mo = instanceKlass::cast(super)->lookup_method(name, signature); 529 if (mo == NULL || mo->access_flags().is_private() ) { 530 // super class hierarchy does not implement it or protection is different 531 return true; 532 } 533 } 534 535 return false; 536 } 537 538 void klassVtable::add_new_mirandas_to_list(GrowableArray<methodOop>* list_of_current_mirandas, 539 objArrayOop current_interface_methods, 540 objArrayOop class_methods, 541 klassOop super) { 542 // iterate thru the current interface's method to see if it a miranda 543 int num_methods = current_interface_methods->length(); 544 for (int i = 0; i < num_methods; i++) { 545 methodOop im = methodOop(current_interface_methods->obj_at(i)); 546 bool is_duplicate = false; 547 int num_of_current_mirandas = list_of_current_mirandas->length(); 548 // check for duplicate mirandas in different interfaces we implement 549 for (int j = 0; j < num_of_current_mirandas; j++) { 550 methodOop miranda = list_of_current_mirandas->at(j); 551 if ((im->name() == miranda->name()) && 552 (im->signature() == miranda->signature())) { 553 is_duplicate = true; 554 break; 555 } 556 } 557 558 if (!is_duplicate) { // we don't want duplicate miranda entries in the vtable 559 if (is_miranda(im, class_methods, super)) { // is it a miranda at all? 560 instanceKlass *sk = instanceKlass::cast(super); 561 // check if it is a duplicate of a super's miranda 562 if (sk->lookup_method_in_all_interfaces(im->name(), im->signature()) == NULL) { 563 list_of_current_mirandas->append(im); 564 } 565 } 566 } 567 } 568 } 569 570 void klassVtable::get_mirandas(GrowableArray<methodOop>* mirandas, 571 klassOop super, objArrayOop class_methods, 572 objArrayOop local_interfaces) { 573 assert((mirandas->length() == 0) , "current mirandas must be 0"); 574 575 // iterate thru the local interfaces looking for a miranda 576 int num_local_ifs = local_interfaces->length(); 577 for (int i = 0; i < num_local_ifs; i++) { 578 instanceKlass *ik = instanceKlass::cast(klassOop(local_interfaces->obj_at(i))); 579 add_new_mirandas_to_list(mirandas, ik->methods(), class_methods, super); 580 // iterate thru each local's super interfaces 581 objArrayOop super_ifs = ik->transitive_interfaces(); 582 int num_super_ifs = super_ifs->length(); 583 for (int j = 0; j < num_super_ifs; j++) { 584 instanceKlass *sik = instanceKlass::cast(klassOop(super_ifs->obj_at(j))); 585 add_new_mirandas_to_list(mirandas, sik->methods(), class_methods, super); 586 } 587 } 588 } 589 590 // get number of mirandas 591 int klassVtable::get_num_mirandas(klassOop super, objArrayOop class_methods, objArrayOop local_interfaces) { 592 ResourceMark rm; 593 GrowableArray<methodOop>* mirandas = new GrowableArray<methodOop>(20); 594 get_mirandas(mirandas, super, class_methods, local_interfaces); 595 return mirandas->length(); 596 } 597 598 // fill in mirandas 599 void klassVtable::fill_in_mirandas(int& initialized) { 600 ResourceMark rm; 601 GrowableArray<methodOop>* mirandas = new GrowableArray<methodOop>(20); 602 instanceKlass *this_ik = ik(); 603 get_mirandas(mirandas, this_ik->super(), this_ik->methods(), this_ik->local_interfaces()); 604 int num_mirandas = mirandas->length(); 605 for (int i = 0; i < num_mirandas; i++) { 606 put_method_at(mirandas->at(i), initialized); 607 initialized++; 608 } 609 } 610 611 void klassVtable::copy_vtable_to(vtableEntry* start) { 612 Copy::disjoint_words((HeapWord*)table(), (HeapWord*)start, _length * vtableEntry::size()); 613 } 614 615 void klassVtable::adjust_method_entries(methodOop* old_methods, methodOop* new_methods, 616 int methods_length, bool * trace_name_printed) { 617 // search the vtable for uses of either obsolete or EMCP methods 618 for (int j = 0; j < methods_length; j++) { 619 methodOop old_method = old_methods[j]; 620 methodOop new_method = new_methods[j]; 621 622 // In the vast majority of cases we could get the vtable index 623 // by using: old_method->vtable_index() 624 // However, there are rare cases, eg. sun.awt.X11.XDecoratedPeer.getX() 625 // in sun.awt.X11.XFramePeer where methods occur more than once in the 626 // vtable, so, alas, we must do an exhaustive search. 627 for (int index = 0; index < length(); index++) { 628 if (unchecked_method_at(index) == old_method) { 629 put_method_at(new_method, index); 630 631 if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) { 632 if (!(*trace_name_printed)) { 633 // RC_TRACE_MESG macro has an embedded ResourceMark 634 RC_TRACE_MESG(("adjust: name=%s", 635 Klass::cast(old_method->method_holder())->external_name())); 636 *trace_name_printed = true; 637 } 638 // RC_TRACE macro has an embedded ResourceMark 639 RC_TRACE(0x00100000, ("vtable method update: %s(%s)", 640 new_method->name()->as_C_string(), 641 new_method->signature()->as_C_string())); 642 } 643 // cannot 'break' here; see for-loop comment above. 644 } 645 } 646 } 647 } 648 649 // a vtable should never contain old or obsolete methods 650 bool klassVtable::check_no_old_or_obsolete_entries() { 651 for (int i = 0; i < length(); i++) { 652 methodOop m = unchecked_method_at(i); 653 if (m != NULL && (m->is_old() || m->is_obsolete())) { 654 return false; 655 } 656 } 657 return true; 658 } 659 660 void klassVtable::dump_vtable() { 661 tty->print_cr("vtable dump --"); 662 for (int i = 0; i < length(); i++) { 663 methodOop m = unchecked_method_at(i); 664 if (m != NULL) { 665 tty->print(" (%5d) ", i); 666 m->access_flags().print_on(tty); 667 tty->print(" -- "); 668 m->print_name(tty); 669 tty->cr(); 670 } 671 } 672 } 673 674 // CDS/RedefineClasses support - clear vtables so they can be reinitialized 675 void klassVtable::clear_vtable() { 676 for (int i = 0; i < _length; i++) table()[i].clear(); 677 } 678 679 bool klassVtable::is_initialized() { 680 return _length == 0 || table()[0].method() != NULL; 681 } 682 683 684 // Garbage collection 685 void klassVtable::oop_follow_contents() { 686 int len = length(); 687 for (int i = 0; i < len; i++) { 688 MarkSweep::mark_and_push(adr_method_at(i)); 689 } 690 } 691 692 #ifndef SERIALGC 693 void klassVtable::oop_follow_contents(ParCompactionManager* cm) { 694 int len = length(); 695 for (int i = 0; i < len; i++) { 696 PSParallelCompact::mark_and_push(cm, adr_method_at(i)); 697 } 698 } 699 #endif // SERIALGC 700 701 void klassVtable::oop_adjust_pointers() { 702 int len = length(); 703 for (int i = 0; i < len; i++) { 704 MarkSweep::adjust_pointer(adr_method_at(i)); 705 } 706 } 707 708 #ifndef SERIALGC 709 void klassVtable::oop_update_pointers(ParCompactionManager* cm) { 710 const int n = length(); 711 for (int i = 0; i < n; i++) { 712 PSParallelCompact::adjust_pointer(adr_method_at(i)); 713 } 714 } 715 #endif // SERIALGC 716 717 // Iterators 718 void klassVtable::oop_oop_iterate(OopClosure* blk) { 719 int len = length(); 720 for (int i = 0; i < len; i++) { 721 blk->do_oop(adr_method_at(i)); 722 } 723 } 724 725 void klassVtable::oop_oop_iterate_m(OopClosure* blk, MemRegion mr) { 726 int len = length(); 727 int i; 728 for (i = 0; i < len; i++) { 729 if ((HeapWord*)adr_method_at(i) >= mr.start()) break; 730 } 731 for (; i < len; i++) { 732 oop* adr = adr_method_at(i); 733 if ((HeapWord*)adr < mr.end()) blk->do_oop(adr); 734 } 735 } 736 737 //----------------------------------------------------------------------------------------- 738 // Itable code 739 740 // Initialize a itableMethodEntry 741 void itableMethodEntry::initialize(methodOop m) { 742 if (m == NULL) return; 743 744 _method = m; 745 } 746 747 klassItable::klassItable(instanceKlassHandle klass) { 748 _klass = klass; 749 750 if (klass->itable_length() > 0) { 751 itableOffsetEntry* offset_entry = (itableOffsetEntry*)klass->start_of_itable(); 752 if (offset_entry != NULL && offset_entry->interface_klass() != NULL) { // Check that itable is initialized 753 // First offset entry points to the first method_entry 754 intptr_t* method_entry = (intptr_t *)(((address)klass->as_klassOop()) + offset_entry->offset()); 755 intptr_t* end = klass->end_of_itable(); 756 757 _table_offset = (intptr_t*)offset_entry - (intptr_t*)klass->as_klassOop(); 758 _size_offset_table = (method_entry - ((intptr_t*)offset_entry)) / itableOffsetEntry::size(); 759 _size_method_table = (end - method_entry) / itableMethodEntry::size(); 760 assert(_table_offset >= 0 && _size_offset_table >= 0 && _size_method_table >= 0, "wrong computation"); 761 return; 762 } 763 } 764 765 // The length of the itable was either zero, or it has not yet been initialized. 766 _table_offset = 0; 767 _size_offset_table = 0; 768 _size_method_table = 0; 769 } 770 771 // Garbage Collection 772 773 void klassItable::oop_follow_contents() { 774 // offset table 775 itableOffsetEntry* ioe = offset_entry(0); 776 for(int i = 0; i < _size_offset_table; i++) { 777 MarkSweep::mark_and_push((oop*)&ioe->_interface); 778 ioe++; 779 } 780 781 // method table 782 itableMethodEntry* ime = method_entry(0); 783 for(int j = 0; j < _size_method_table; j++) { 784 MarkSweep::mark_and_push((oop*)&ime->_method); 785 ime++; 786 } 787 } 788 789 #ifndef SERIALGC 790 void klassItable::oop_follow_contents(ParCompactionManager* cm) { 791 // offset table 792 itableOffsetEntry* ioe = offset_entry(0); 793 for(int i = 0; i < _size_offset_table; i++) { 794 PSParallelCompact::mark_and_push(cm, (oop*)&ioe->_interface); 795 ioe++; 796 } 797 798 // method table 799 itableMethodEntry* ime = method_entry(0); 800 for(int j = 0; j < _size_method_table; j++) { 801 PSParallelCompact::mark_and_push(cm, (oop*)&ime->_method); 802 ime++; 803 } 804 } 805 #endif // SERIALGC 806 807 void klassItable::oop_adjust_pointers() { 808 // offset table 809 itableOffsetEntry* ioe = offset_entry(0); 810 for(int i = 0; i < _size_offset_table; i++) { 811 MarkSweep::adjust_pointer((oop*)&ioe->_interface); 812 ioe++; 813 } 814 815 // method table 816 itableMethodEntry* ime = method_entry(0); 817 for(int j = 0; j < _size_method_table; j++) { 818 MarkSweep::adjust_pointer((oop*)&ime->_method); 819 ime++; 820 } 821 } 822 823 #ifndef SERIALGC 824 void klassItable::oop_update_pointers(ParCompactionManager* cm) { 825 // offset table 826 itableOffsetEntry* ioe = offset_entry(0); 827 for(int i = 0; i < _size_offset_table; i++) { 828 PSParallelCompact::adjust_pointer((oop*)&ioe->_interface); 829 ioe++; 830 } 831 832 // method table 833 itableMethodEntry* ime = method_entry(0); 834 for(int j = 0; j < _size_method_table; j++) { 835 PSParallelCompact::adjust_pointer((oop*)&ime->_method); 836 ime++; 837 } 838 } 839 #endif // SERIALGC 840 841 // Iterators 842 void klassItable::oop_oop_iterate(OopClosure* blk) { 843 // offset table 844 itableOffsetEntry* ioe = offset_entry(0); 845 for(int i = 0; i < _size_offset_table; i++) { 846 blk->do_oop((oop*)&ioe->_interface); 847 ioe++; 848 } 849 850 // method table 851 itableMethodEntry* ime = method_entry(0); 852 for(int j = 0; j < _size_method_table; j++) { 853 blk->do_oop((oop*)&ime->_method); 854 ime++; 855 } 856 } 857 858 void klassItable::oop_oop_iterate_m(OopClosure* blk, MemRegion mr) { 859 // offset table 860 itableOffsetEntry* ioe = offset_entry(0); 861 for(int i = 0; i < _size_offset_table; i++) { 862 oop* adr = (oop*)&ioe->_interface; 863 if (mr.contains(adr)) blk->do_oop(adr); 864 ioe++; 865 } 866 867 // method table 868 itableMethodEntry* ime = method_entry(0); 869 for(int j = 0; j < _size_method_table; j++) { 870 oop* adr = (oop*)&ime->_method; 871 if (mr.contains(adr)) blk->do_oop(adr); 872 ime++; 873 } 874 } 875 876 877 static int initialize_count = 0; 878 879 // Initialization 880 void klassItable::initialize_itable(bool checkconstraints, TRAPS) { 881 // Cannot be setup doing bootstrapping, interfaces don't have 882 // itables, and klass with only ones entry have empty itables 883 if (Universe::is_bootstrapping() || 884 _klass->is_interface() || 885 _klass->itable_length() == itableOffsetEntry::size()) return; 886 887 // There's alway an extra itable entry so we can null-terminate it. 888 guarantee(size_offset_table() >= 1, "too small"); 889 int num_interfaces = size_offset_table() - 1; 890 if (num_interfaces > 0) { 891 if (TraceItables) tty->print_cr("%3d: Initializing itables for %s", ++initialize_count, 892 _klass->name()->as_C_string()); 893 894 895 // Iterate through all interfaces 896 int i; 897 for(i = 0; i < num_interfaces; i++) { 898 itableOffsetEntry* ioe = offset_entry(i); 899 KlassHandle interf_h (THREAD, ioe->interface_klass()); 900 assert(interf_h() != NULL && ioe->offset() != 0, "bad offset entry in itable"); 901 initialize_itable_for_interface(ioe->offset(), interf_h, checkconstraints, CHECK); 902 } 903 904 } 905 // Check that the last entry is empty 906 itableOffsetEntry* ioe = offset_entry(size_offset_table() - 1); 907 guarantee(ioe->interface_klass() == NULL && ioe->offset() == 0, "terminator entry missing"); 908 } 909 910 911 void klassItable::initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS) { 912 objArrayHandle methods(THREAD, instanceKlass::cast(interf_h())->methods()); 913 int nof_methods = methods()->length(); 914 HandleMark hm; 915 KlassHandle klass = _klass; 916 assert(nof_methods > 0, "at least one method must exist for interface to be in vtable"); 917 Handle interface_loader (THREAD, instanceKlass::cast(interf_h())->class_loader()); 918 int ime_num = 0; 919 920 // Skip first methodOop if it is a class initializer 921 int i = ((methodOop)methods()->obj_at(0))->is_static_initializer() ? 1 : 0; 922 923 // m, method_name, method_signature, klass reset each loop so they 924 // don't need preserving across check_signature_loaders call 925 // methods needs a handle in case of gc from check_signature_loaders 926 for(; i < nof_methods; i++) { 927 methodOop m = (methodOop)methods()->obj_at(i); 928 Symbol* method_name = m->name(); 929 Symbol* method_signature = m->signature(); 930 931 // This is same code as in Linkresolver::lookup_instance_method_in_klasses 932 methodOop target = klass->uncached_lookup_method(method_name, method_signature); 933 while (target != NULL && target->is_static()) { 934 // continue with recursive lookup through the superclass 935 klassOop super = Klass::cast(target->method_holder())->super(); 936 target = (super == NULL) ? methodOop(NULL) : Klass::cast(super)->uncached_lookup_method(method_name, method_signature); 937 } 938 if (target == NULL || !target->is_public() || target->is_abstract()) { 939 // Entry do not resolve. Leave it empty 940 } else { 941 // Entry did resolve, check loader constraints before initializing 942 // if checkconstraints requested 943 methodHandle target_h (THREAD, target); // preserve across gc 944 if (checkconstraints) { 945 Handle method_holder_loader (THREAD, instanceKlass::cast(target->method_holder())->class_loader()); 946 if (method_holder_loader() != interface_loader()) { 947 ResourceMark rm(THREAD); 948 char* failed_type_name = 949 SystemDictionary::check_signature_loaders(method_signature, 950 method_holder_loader, 951 interface_loader, 952 true, CHECK); 953 if (failed_type_name != NULL) { 954 const char* msg = "loader constraint violation in interface " 955 "itable initialization: when resolving method \"%s\" the class" 956 " loader (instance of %s) of the current class, %s, " 957 "and the class loader (instance of %s) for interface " 958 "%s have different Class objects for the type %s " 959 "used in the signature"; 960 char* sig = target_h()->name_and_sig_as_C_string(); 961 const char* loader1 = SystemDictionary::loader_name(method_holder_loader()); 962 char* current = klass->name()->as_C_string(); 963 const char* loader2 = SystemDictionary::loader_name(interface_loader()); 964 char* iface = instanceKlass::cast(interf_h())->name()->as_C_string(); 965 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) + 966 strlen(current) + strlen(loader2) + strlen(iface) + 967 strlen(failed_type_name); 968 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen); 969 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2, 970 iface, failed_type_name); 971 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf); 972 } 973 } 974 } 975 976 // ime may have moved during GC so recalculate address 977 itableOffsetEntry::method_entry(_klass(), method_table_offset)[ime_num].initialize(target_h()); 978 } 979 // Progress to next entry 980 ime_num++; 981 } 982 } 983 984 // Update entry for specific methodOop 985 void klassItable::initialize_with_method(methodOop m) { 986 itableMethodEntry* ime = method_entry(0); 987 for(int i = 0; i < _size_method_table; i++) { 988 if (ime->method() == m) { 989 ime->initialize(m); 990 } 991 ime++; 992 } 993 } 994 995 void klassItable::adjust_method_entries(methodOop* old_methods, methodOop* new_methods, 996 int methods_length, bool * trace_name_printed) { 997 // search the itable for uses of either obsolete or EMCP methods 998 for (int j = 0; j < methods_length; j++) { 999 methodOop old_method = old_methods[j]; 1000 methodOop new_method = new_methods[j]; 1001 itableMethodEntry* ime = method_entry(0); 1002 1003 // The itable can describe more than one interface and the same 1004 // method signature can be specified by more than one interface. 1005 // This means we have to do an exhaustive search to find all the 1006 // old_method references. 1007 for (int i = 0; i < _size_method_table; i++) { 1008 if (ime->method() == old_method) { 1009 ime->initialize(new_method); 1010 1011 if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) { 1012 if (!(*trace_name_printed)) { 1013 // RC_TRACE_MESG macro has an embedded ResourceMark 1014 RC_TRACE_MESG(("adjust: name=%s", 1015 Klass::cast(old_method->method_holder())->external_name())); 1016 *trace_name_printed = true; 1017 } 1018 // RC_TRACE macro has an embedded ResourceMark 1019 RC_TRACE(0x00200000, ("itable method update: %s(%s)", 1020 new_method->name()->as_C_string(), 1021 new_method->signature()->as_C_string())); 1022 } 1023 // cannot 'break' here; see for-loop comment above. 1024 } 1025 ime++; 1026 } 1027 } 1028 } 1029 1030 // an itable should never contain old or obsolete methods 1031 bool klassItable::check_no_old_or_obsolete_entries() { 1032 itableMethodEntry* ime = method_entry(0); 1033 for (int i = 0; i < _size_method_table; i++) { 1034 methodOop m = ime->method(); 1035 if (m != NULL && (m->is_old() || m->is_obsolete())) { 1036 return false; 1037 } 1038 ime++; 1039 } 1040 return true; 1041 } 1042 1043 void klassItable::dump_itable() { 1044 itableMethodEntry* ime = method_entry(0); 1045 tty->print_cr("itable dump --"); 1046 for (int i = 0; i < _size_method_table; i++) { 1047 methodOop m = ime->method(); 1048 if (m != NULL) { 1049 tty->print(" (%5d) ", i); 1050 m->access_flags().print_on(tty); 1051 tty->print(" -- "); 1052 m->print_name(tty); 1053 tty->cr(); 1054 } 1055 ime++; 1056 } 1057 } 1058 1059 1060 // Setup 1061 class InterfaceVisiterClosure : public StackObj { 1062 public: 1063 virtual void doit(klassOop intf, int method_count) = 0; 1064 }; 1065 1066 // Visit all interfaces with at-least one method (excluding <clinit>) 1067 void visit_all_interfaces(objArrayOop transitive_intf, InterfaceVisiterClosure *blk) { 1068 // Handle array argument 1069 for(int i = 0; i < transitive_intf->length(); i++) { 1070 klassOop intf = (klassOop)transitive_intf->obj_at(i); 1071 assert(Klass::cast(intf)->is_interface(), "sanity check"); 1072 1073 // Find no. of methods excluding a <clinit> 1074 int method_count = instanceKlass::cast(intf)->methods()->length(); 1075 if (method_count > 0) { 1076 methodOop m = (methodOop)instanceKlass::cast(intf)->methods()->obj_at(0); 1077 assert(m != NULL && m->is_method(), "sanity check"); 1078 if (m->name() == vmSymbols::object_initializer_name()) { 1079 method_count--; 1080 } 1081 } 1082 1083 // Only count interfaces with at least one method 1084 if (method_count > 0) { 1085 blk->doit(intf, method_count); 1086 } 1087 } 1088 } 1089 1090 class CountInterfacesClosure : public InterfaceVisiterClosure { 1091 private: 1092 int _nof_methods; 1093 int _nof_interfaces; 1094 public: 1095 CountInterfacesClosure() { _nof_methods = 0; _nof_interfaces = 0; } 1096 1097 int nof_methods() const { return _nof_methods; } 1098 int nof_interfaces() const { return _nof_interfaces; } 1099 1100 void doit(klassOop intf, int method_count) { _nof_methods += method_count; _nof_interfaces++; } 1101 }; 1102 1103 class SetupItableClosure : public InterfaceVisiterClosure { 1104 private: 1105 itableOffsetEntry* _offset_entry; 1106 itableMethodEntry* _method_entry; 1107 address _klass_begin; 1108 public: 1109 SetupItableClosure(address klass_begin, itableOffsetEntry* offset_entry, itableMethodEntry* method_entry) { 1110 _klass_begin = klass_begin; 1111 _offset_entry = offset_entry; 1112 _method_entry = method_entry; 1113 } 1114 1115 itableMethodEntry* method_entry() const { return _method_entry; } 1116 1117 void doit(klassOop intf, int method_count) { 1118 int offset = ((address)_method_entry) - _klass_begin; 1119 _offset_entry->initialize(intf, offset); 1120 _offset_entry++; 1121 _method_entry += method_count; 1122 } 1123 }; 1124 1125 int klassItable::compute_itable_size(objArrayHandle transitive_interfaces) { 1126 // Count no of interfaces and total number of interface methods 1127 CountInterfacesClosure cic; 1128 visit_all_interfaces(transitive_interfaces(), &cic); 1129 1130 // There's alway an extra itable entry so we can null-terminate it. 1131 int itable_size = calc_itable_size(cic.nof_interfaces() + 1, cic.nof_methods()); 1132 1133 // Statistics 1134 update_stats(itable_size * HeapWordSize); 1135 1136 return itable_size; 1137 } 1138 1139 1140 // Fill out offset table and interface klasses into the itable space 1141 void klassItable::setup_itable_offset_table(instanceKlassHandle klass) { 1142 if (klass->itable_length() == 0) return; 1143 assert(!klass->is_interface(), "Should have zero length itable"); 1144 1145 // Count no of interfaces and total number of interface methods 1146 CountInterfacesClosure cic; 1147 visit_all_interfaces(klass->transitive_interfaces(), &cic); 1148 int nof_methods = cic.nof_methods(); 1149 int nof_interfaces = cic.nof_interfaces(); 1150 1151 // Add one extra entry so we can null-terminate the table 1152 nof_interfaces++; 1153 1154 assert(compute_itable_size(objArrayHandle(klass->transitive_interfaces())) == 1155 calc_itable_size(nof_interfaces, nof_methods), 1156 "mismatch calculation of itable size"); 1157 1158 // Fill-out offset table 1159 itableOffsetEntry* ioe = (itableOffsetEntry*)klass->start_of_itable(); 1160 itableMethodEntry* ime = (itableMethodEntry*)(ioe + nof_interfaces); 1161 intptr_t* end = klass->end_of_itable(); 1162 assert((oop*)(ime + nof_methods) <= (oop*)klass->start_of_nonstatic_oop_maps(), "wrong offset calculation (1)"); 1163 assert((oop*)(end) == (oop*)(ime + nof_methods), "wrong offset calculation (2)"); 1164 1165 // Visit all interfaces and initialize itable offset table 1166 SetupItableClosure sic((address)klass->as_klassOop(), ioe, ime); 1167 visit_all_interfaces(klass->transitive_interfaces(), &sic); 1168 1169 #ifdef ASSERT 1170 ime = sic.method_entry(); 1171 oop* v = (oop*) klass->end_of_itable(); 1172 assert( (oop*)(ime) == v, "wrong offset calculation (2)"); 1173 #endif 1174 } 1175 1176 1177 // m must be a method in an interface 1178 int klassItable::compute_itable_index(methodOop m) { 1179 klassOop intf = m->method_holder(); 1180 assert(instanceKlass::cast(intf)->is_interface(), "sanity check"); 1181 objArrayOop methods = instanceKlass::cast(intf)->methods(); 1182 int index = 0; 1183 while(methods->obj_at(index) != m) { 1184 index++; 1185 assert(index < methods->length(), "should find index for resolve_invoke"); 1186 } 1187 // Adjust for <clinit>, which is left out of table if first method 1188 if (methods->length() > 0 && ((methodOop)methods->obj_at(0))->is_static_initializer()) { 1189 index--; 1190 } 1191 return index; 1192 } 1193 1194 1195 // inverse to compute_itable_index 1196 methodOop klassItable::method_for_itable_index(klassOop intf, int itable_index) { 1197 assert(instanceKlass::cast(intf)->is_interface(), "sanity check"); 1198 objArrayOop methods = instanceKlass::cast(intf)->methods(); 1199 1200 int index = itable_index; 1201 // Adjust for <clinit>, which is left out of table if first method 1202 if (methods->length() > 0 && ((methodOop)methods->obj_at(0))->is_static_initializer()) { 1203 index++; 1204 } 1205 1206 if (itable_index < 0 || index >= methods->length()) 1207 return NULL; // help caller defend against bad indexes 1208 1209 methodOop m = (methodOop)methods->obj_at(index); 1210 assert(compute_itable_index(m) == itable_index, "correct inverse"); 1211 1212 return m; 1213 } 1214 1215 void klassVtable::verify(outputStream* st, bool forced) { 1216 // make sure table is initialized 1217 if (!Universe::is_fully_initialized()) return; 1218 #ifndef PRODUCT 1219 // avoid redundant verifies 1220 if (!forced && _verify_count == Universe::verify_count()) return; 1221 _verify_count = Universe::verify_count(); 1222 #endif 1223 oop* end_of_obj = (oop*)_klass() + _klass()->size(); 1224 oop* end_of_vtable = (oop *)&table()[_length]; 1225 if (end_of_vtable > end_of_obj) { 1226 fatal(err_msg("klass %s: klass object too short (vtable extends beyond " 1227 "end)", _klass->internal_name())); 1228 } 1229 1230 for (int i = 0; i < _length; i++) table()[i].verify(this, st); 1231 // verify consistency with superKlass vtable 1232 klassOop super = _klass->super(); 1233 if (super != NULL) { 1234 instanceKlass* sk = instanceKlass::cast(super); 1235 klassVtable* vt = sk->vtable(); 1236 for (int i = 0; i < vt->length(); i++) { 1237 verify_against(st, vt, i); 1238 } 1239 } 1240 } 1241 1242 void klassVtable::verify_against(outputStream* st, klassVtable* vt, int index) { 1243 vtableEntry* vte = &vt->table()[index]; 1244 if (vte->method()->name() != table()[index].method()->name() || 1245 vte->method()->signature() != table()[index].method()->signature()) { 1246 fatal("mismatched name/signature of vtable entries"); 1247 } 1248 } 1249 1250 #ifndef PRODUCT 1251 void klassVtable::print() { 1252 ResourceMark rm; 1253 tty->print("klassVtable for klass %s (length %d):\n", _klass->internal_name(), length()); 1254 for (int i = 0; i < length(); i++) { 1255 table()[i].print(); 1256 tty->cr(); 1257 } 1258 } 1259 #endif 1260 1261 void vtableEntry::verify(klassVtable* vt, outputStream* st) { 1262 NOT_PRODUCT(FlagSetting fs(IgnoreLockingAssertions, true)); 1263 assert(method() != NULL, "must have set method"); 1264 method()->verify(); 1265 // we sub_type, because it could be a miranda method 1266 if (!vt->klass()->is_subtype_of(method()->method_holder())) { 1267 #ifndef PRODUCT 1268 print(); 1269 #endif 1270 fatal(err_msg("vtableEntry " PTR_FORMAT ": method is from subclass", this)); 1271 } 1272 } 1273 1274 #ifndef PRODUCT 1275 1276 void vtableEntry::print() { 1277 ResourceMark rm; 1278 tty->print("vtableEntry %s: ", method()->name()->as_C_string()); 1279 if (Verbose) { 1280 tty->print("m %#lx ", (address)method()); 1281 } 1282 } 1283 1284 class VtableStats : AllStatic { 1285 public: 1286 static int no_klasses; // # classes with vtables 1287 static int no_array_klasses; // # array classes 1288 static int no_instance_klasses; // # instanceKlasses 1289 static int sum_of_vtable_len; // total # of vtable entries 1290 static int sum_of_array_vtable_len; // total # of vtable entries in array klasses only 1291 static int fixed; // total fixed overhead in bytes 1292 static int filler; // overhead caused by filler bytes 1293 static int entries; // total bytes consumed by vtable entries 1294 static int array_entries; // total bytes consumed by array vtable entries 1295 1296 static void do_class(klassOop k) { 1297 Klass* kl = k->klass_part(); 1298 klassVtable* vt = kl->vtable(); 1299 if (vt == NULL) return; 1300 no_klasses++; 1301 if (kl->oop_is_instance()) { 1302 no_instance_klasses++; 1303 kl->array_klasses_do(do_class); 1304 } 1305 if (kl->oop_is_array()) { 1306 no_array_klasses++; 1307 sum_of_array_vtable_len += vt->length(); 1308 } 1309 sum_of_vtable_len += vt->length(); 1310 } 1311 1312 static void compute() { 1313 SystemDictionary::classes_do(do_class); 1314 fixed = no_klasses * oopSize; // vtable length 1315 // filler size is a conservative approximation 1316 filler = oopSize * (no_klasses - no_instance_klasses) * (sizeof(instanceKlass) - sizeof(arrayKlass) - 1); 1317 entries = sizeof(vtableEntry) * sum_of_vtable_len; 1318 array_entries = sizeof(vtableEntry) * sum_of_array_vtable_len; 1319 } 1320 }; 1321 1322 int VtableStats::no_klasses = 0; 1323 int VtableStats::no_array_klasses = 0; 1324 int VtableStats::no_instance_klasses = 0; 1325 int VtableStats::sum_of_vtable_len = 0; 1326 int VtableStats::sum_of_array_vtable_len = 0; 1327 int VtableStats::fixed = 0; 1328 int VtableStats::filler = 0; 1329 int VtableStats::entries = 0; 1330 int VtableStats::array_entries = 0; 1331 1332 void klassVtable::print_statistics() { 1333 ResourceMark rm; 1334 HandleMark hm; 1335 VtableStats::compute(); 1336 tty->print_cr("vtable statistics:"); 1337 tty->print_cr("%6d classes (%d instance, %d array)", VtableStats::no_klasses, VtableStats::no_instance_klasses, VtableStats::no_array_klasses); 1338 int total = VtableStats::fixed + VtableStats::filler + VtableStats::entries; 1339 tty->print_cr("%6d bytes fixed overhead (refs + vtable object header)", VtableStats::fixed); 1340 tty->print_cr("%6d bytes filler overhead", VtableStats::filler); 1341 tty->print_cr("%6d bytes for vtable entries (%d for arrays)", VtableStats::entries, VtableStats::array_entries); 1342 tty->print_cr("%6d bytes total", total); 1343 } 1344 1345 int klassItable::_total_classes; // Total no. of classes with itables 1346 long klassItable::_total_size; // Total no. of bytes used for itables 1347 1348 void klassItable::print_statistics() { 1349 tty->print_cr("itable statistics:"); 1350 tty->print_cr("%6d classes with itables", _total_classes); 1351 tty->print_cr("%6d K uses for itables (average by class: %d bytes)", _total_size / K, _total_size / _total_classes); 1352 } 1353 1354 #endif // PRODUCT