klassVtable.cpp revision 6412:53a41e7cbe05
1/* 2 * Copyright (c) 1997, 2014, 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/klassVtable.hpp" 34#include "oops/method.hpp" 35#include "oops/objArrayOop.hpp" 36#include "oops/oop.inline.hpp" 37#include "prims/jvmtiRedefineClassesTrace.hpp" 38#include "runtime/arguments.hpp" 39#include "runtime/handles.inline.hpp" 40#include "utilities/copy.hpp" 41 42PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC 43 44inline InstanceKlass* klassVtable::ik() const { 45 Klass* k = _klass(); 46 assert(k->oop_is_instance(), "not an InstanceKlass"); 47 return (InstanceKlass*)k; 48} 49 50 51// this function computes the vtable size (including the size needed for miranda 52// methods) and the number of miranda methods in this class. 53// Note on Miranda methods: Let's say there is a class C that implements 54// interface I, and none of C's superclasses implements I. 55// Let's say there is an abstract method m in I that neither C 56// nor any of its super classes implement (i.e there is no method of any access, 57// with the same name and signature as m), then m is a Miranda method which is 58// entered as a public abstract method in C's vtable. From then on it should 59// treated as any other public method in C for method over-ride purposes. 60void klassVtable::compute_vtable_size_and_num_mirandas( 61 int* vtable_length_ret, int* num_new_mirandas, 62 GrowableArray<Method*>* all_mirandas, Klass* super, 63 Array<Method*>* methods, AccessFlags class_flags, 64 Handle classloader, Symbol* classname, Array<Klass*>* local_interfaces, 65 TRAPS) { 66 No_Safepoint_Verifier nsv; 67 68 // set up default result values 69 int vtable_length = 0; 70 71 // start off with super's vtable length 72 InstanceKlass* sk = (InstanceKlass*)super; 73 vtable_length = super == NULL ? 0 : sk->vtable_length(); 74 75 // go thru each method in the methods table to see if it needs a new entry 76 int len = methods->length(); 77 for (int i = 0; i < len; i++) { 78 assert(methods->at(i)->is_method(), "must be a Method*"); 79 methodHandle mh(THREAD, methods->at(i)); 80 81 if (needs_new_vtable_entry(mh, super, classloader, classname, class_flags, THREAD)) { 82 vtable_length += vtableEntry::size(); // we need a new entry 83 } 84 } 85 86 GrowableArray<Method*> new_mirandas(20); 87 // compute the number of mirandas methods that must be added to the end 88 get_mirandas(&new_mirandas, all_mirandas, super, methods, NULL, local_interfaces); 89 *num_new_mirandas = new_mirandas.length(); 90 91 // Interfaces do not need interface methods in their vtables 92 // This includes miranda methods and during later processing, default methods 93 if (!class_flags.is_interface()) { 94 vtable_length += *num_new_mirandas * vtableEntry::size(); 95 } 96 97 if (Universe::is_bootstrapping() && vtable_length == 0) { 98 // array classes don't have their superclass set correctly during 99 // bootstrapping 100 vtable_length = Universe::base_vtable_size(); 101 } 102 103 if (super == NULL && !Universe::is_bootstrapping() && 104 vtable_length != Universe::base_vtable_size()) { 105 // Someone is attempting to redefine java.lang.Object incorrectly. The 106 // only way this should happen is from 107 // SystemDictionary::resolve_from_stream(), which will detect this later 108 // and throw a security exception. So don't assert here to let 109 // the exception occur. 110 vtable_length = Universe::base_vtable_size(); 111 } 112 assert(super != NULL || vtable_length == Universe::base_vtable_size(), 113 "bad vtable size for class Object"); 114 assert(vtable_length % vtableEntry::size() == 0, "bad vtable length"); 115 assert(vtable_length >= Universe::base_vtable_size(), "vtable too small"); 116 117 *vtable_length_ret = vtable_length; 118} 119 120int klassVtable::index_of(Method* m, int len) const { 121 assert(m->has_vtable_index(), "do not ask this of non-vtable methods"); 122 return m->vtable_index(); 123} 124 125// Copy super class's vtable to the first part (prefix) of this class's vtable, 126// and return the number of entries copied. Expects that 'super' is the Java 127// super class (arrays can have "array" super classes that must be skipped). 128int klassVtable::initialize_from_super(KlassHandle super) { 129 if (super.is_null()) { 130 return 0; 131 } else { 132 // copy methods from superKlass 133 // can't inherit from array class, so must be InstanceKlass 134 assert(super->oop_is_instance(), "must be instance klass"); 135 InstanceKlass* sk = (InstanceKlass*)super(); 136 klassVtable* superVtable = sk->vtable(); 137 assert(superVtable->length() <= _length, "vtable too short"); 138#ifdef ASSERT 139 superVtable->verify(tty, true); 140#endif 141 superVtable->copy_vtable_to(table()); 142#ifndef PRODUCT 143 if (PrintVtables && Verbose) { 144 ResourceMark rm; 145 tty->print_cr("copy vtable from %s to %s size %d", sk->internal_name(), klass()->internal_name(), _length); 146 } 147#endif 148 return superVtable->length(); 149 } 150} 151 152// 153// Revised lookup semantics introduced 1.3 (Kestrel beta) 154void klassVtable::initialize_vtable(bool checkconstraints, TRAPS) { 155 156 // Note: Arrays can have intermediate array supers. Use java_super to skip them. 157 KlassHandle super (THREAD, klass()->java_super()); 158 int nofNewEntries = 0; 159 160 if (PrintVtables && !klass()->oop_is_array()) { 161 ResourceMark rm(THREAD); 162 tty->print_cr("Initializing: %s", _klass->name()->as_C_string()); 163 } 164 165#ifdef ASSERT 166 oop* end_of_obj = (oop*)_klass() + _klass()->size(); 167 oop* end_of_vtable = (oop*)&table()[_length]; 168 assert(end_of_vtable <= end_of_obj, "vtable extends beyond end"); 169#endif 170 171 if (Universe::is_bootstrapping()) { 172 // just clear everything 173 for (int i = 0; i < _length; i++) table()[i].clear(); 174 return; 175 } 176 177 int super_vtable_len = initialize_from_super(super); 178 if (klass()->oop_is_array()) { 179 assert(super_vtable_len == _length, "arrays shouldn't introduce new methods"); 180 } else { 181 assert(_klass->oop_is_instance(), "must be InstanceKlass"); 182 183 Array<Method*>* methods = ik()->methods(); 184 int len = methods->length(); 185 int initialized = super_vtable_len; 186 187 // Check each of this class's methods against super; 188 // if override, replace in copy of super vtable, otherwise append to end 189 for (int i = 0; i < len; i++) { 190 // update_inherited_vtable can stop for gc - ensure using handles 191 HandleMark hm(THREAD); 192 assert(methods->at(i)->is_method(), "must be a Method*"); 193 methodHandle mh(THREAD, methods->at(i)); 194 195 bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, -1, checkconstraints, CHECK); 196 197 if (needs_new_entry) { 198 put_method_at(mh(), initialized); 199 mh()->set_vtable_index(initialized); // set primary vtable index 200 initialized++; 201 } 202 } 203 204 // update vtable with default_methods 205 Array<Method*>* default_methods = ik()->default_methods(); 206 if (default_methods != NULL) { 207 len = default_methods->length(); 208 if (len > 0) { 209 Array<int>* def_vtable_indices = NULL; 210 if ((def_vtable_indices = ik()->default_vtable_indices()) == NULL) { 211 def_vtable_indices = ik()->create_new_default_vtable_indices(len, CHECK); 212 } else { 213 assert(def_vtable_indices->length() == len, "reinit vtable len?"); 214 } 215 for (int i = 0; i < len; i++) { 216 HandleMark hm(THREAD); 217 assert(default_methods->at(i)->is_method(), "must be a Method*"); 218 methodHandle mh(THREAD, default_methods->at(i)); 219 220 bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, i, checkconstraints, CHECK); 221 222 // needs new entry 223 if (needs_new_entry) { 224 put_method_at(mh(), initialized); 225 def_vtable_indices->at_put(i, initialized); //set vtable index 226 initialized++; 227 } 228 } 229 } 230 } 231 232 // add miranda methods; it will also return the updated initialized 233 // Interfaces do not need interface methods in their vtables 234 // This includes miranda methods and during later processing, default methods 235 if (!ik()->is_interface()) { 236 initialized = fill_in_mirandas(initialized); 237 } 238 239 // In class hierarchies where the accessibility is not increasing (i.e., going from private -> 240 // package_private -> public/protected), the vtable might actually be smaller than our initial 241 // calculation. 242 assert(initialized <= _length, "vtable initialization failed"); 243 for(;initialized < _length; initialized++) { 244 put_method_at(NULL, initialized); 245 } 246 NOT_PRODUCT(verify(tty, true)); 247 } 248} 249 250// Called for cases where a method does not override its superclass' vtable entry 251// For bytecodes not produced by javac together it is possible that a method does not override 252// the superclass's method, but might indirectly override a super-super class's vtable entry 253// If none found, return a null superk, else return the superk of the method this does override 254InstanceKlass* klassVtable::find_transitive_override(InstanceKlass* initialsuper, methodHandle target_method, 255 int vtable_index, Handle target_loader, Symbol* target_classname, Thread * THREAD) { 256 InstanceKlass* superk = initialsuper; 257 while (superk != NULL && superk->super() != NULL) { 258 InstanceKlass* supersuperklass = InstanceKlass::cast(superk->super()); 259 klassVtable* ssVtable = supersuperklass->vtable(); 260 if (vtable_index < ssVtable->length()) { 261 Method* super_method = ssVtable->method_at(vtable_index); 262#ifndef PRODUCT 263 Symbol* name= target_method()->name(); 264 Symbol* signature = target_method()->signature(); 265 assert(super_method->name() == name && super_method->signature() == signature, "vtable entry name/sig mismatch"); 266#endif 267 if (supersuperklass->is_override(super_method, target_loader, target_classname, THREAD)) { 268#ifndef PRODUCT 269 if (PrintVtables && Verbose) { 270 ResourceMark rm(THREAD); 271 char* sig = target_method()->name_and_sig_as_C_string(); 272 tty->print("transitive overriding superclass %s with %s::%s index %d, original flags: ", 273 supersuperklass->internal_name(), 274 _klass->internal_name(), sig, vtable_index); 275 super_method->access_flags().print_on(tty); 276 if (super_method->is_default_method()) { 277 tty->print("default "); 278 } 279 tty->print("overriders flags: "); 280 target_method->access_flags().print_on(tty); 281 if (target_method->is_default_method()) { 282 tty->print("default "); 283 } 284 } 285#endif /*PRODUCT*/ 286 break; // return found superk 287 } 288 } else { 289 // super class has no vtable entry here, stop transitive search 290 superk = (InstanceKlass*)NULL; 291 break; 292 } 293 // if no override found yet, continue to search up 294 superk = InstanceKlass::cast(superk->super()); 295 } 296 297 return superk; 298} 299 300// Update child's copy of super vtable for overrides 301// OR return true if a new vtable entry is required. 302// Only called for InstanceKlass's, i.e. not for arrays 303// If that changed, could not use _klass as handle for klass 304bool klassVtable::update_inherited_vtable(InstanceKlass* klass, methodHandle target_method, 305 int super_vtable_len, int default_index, 306 bool checkconstraints, TRAPS) { 307 ResourceMark rm; 308 bool allocate_new = true; 309 assert(klass->oop_is_instance(), "must be InstanceKlass"); 310 311 Array<int>* def_vtable_indices = NULL; 312 bool is_default = false; 313 // default methods are concrete methods in superinterfaces which are added to the vtable 314 // with their real method_holder 315 // Since vtable and itable indices share the same storage, don't touch 316 // the default method's real vtable/itable index 317 // default_vtable_indices stores the vtable value relative to this inheritor 318 if (default_index >= 0 ) { 319 is_default = true; 320 def_vtable_indices = klass->default_vtable_indices(); 321 assert(def_vtable_indices != NULL, "def vtable alloc?"); 322 assert(default_index <= def_vtable_indices->length(), "def vtable len?"); 323 } else { 324 assert(klass == target_method()->method_holder(), "caller resp."); 325 // Initialize the method's vtable index to "nonvirtual". 326 // If we allocate a vtable entry, we will update it to a non-negative number. 327 target_method()->set_vtable_index(Method::nonvirtual_vtable_index); 328 } 329 330 // Static and <init> methods are never in 331 if (target_method()->is_static() || target_method()->name() == vmSymbols::object_initializer_name()) { 332 return false; 333 } 334 335 if (target_method->is_final_method(klass->access_flags())) { 336 // a final method never needs a new entry; final methods can be statically 337 // resolved and they have to be present in the vtable only if they override 338 // a super's method, in which case they re-use its entry 339 allocate_new = false; 340 } else if (klass->is_interface()) { 341 allocate_new = false; // see note below in needs_new_vtable_entry 342 // An interface never allocates new vtable slots, only inherits old ones. 343 // This method will either be assigned its own itable index later, 344 // or be assigned an inherited vtable index in the loop below. 345 // default methods inherited by classes store their vtable indices 346 // in the inheritor's default_vtable_indices 347 // default methods inherited by interfaces may already have a 348 // valid itable index, if so, don't change it 349 // overpass methods in an interface will be assigned an itable index later 350 // by an inheriting class 351 if (!is_default || !target_method()->has_itable_index()) { 352 target_method()->set_vtable_index(Method::pending_itable_index); 353 } 354 } 355 356 // we need a new entry if there is no superclass 357 if (klass->super() == NULL) { 358 return allocate_new; 359 } 360 361 // private methods in classes always have a new entry in the vtable 362 // specification interpretation since classic has 363 // private methods not overriding 364 // JDK8 adds private methods in interfaces which require invokespecial 365 if (target_method()->is_private()) { 366 return allocate_new; 367 } 368 369 // search through the vtable and update overridden entries 370 // Since check_signature_loaders acquires SystemDictionary_lock 371 // which can block for gc, once we are in this loop, use handles 372 // For classfiles built with >= jdk7, we now look for transitive overrides 373 374 Symbol* name = target_method()->name(); 375 Symbol* signature = target_method()->signature(); 376 377 KlassHandle target_klass(THREAD, target_method()->method_holder()); 378 if (target_klass == NULL) { 379 target_klass = _klass; 380 } 381 382 Handle target_loader(THREAD, target_klass->class_loader()); 383 384 Symbol* target_classname = target_klass->name(); 385 for(int i = 0; i < super_vtable_len; i++) { 386 Method* super_method = method_at(i); 387 // Check if method name matches 388 if (super_method->name() == name && super_method->signature() == signature) { 389 390 // get super_klass for method_holder for the found method 391 InstanceKlass* super_klass = super_method->method_holder(); 392 393 if (is_default 394 || ((super_klass->is_override(super_method, target_loader, target_classname, THREAD)) 395 || ((klass->major_version() >= VTABLE_TRANSITIVE_OVERRIDE_VERSION) 396 && ((super_klass = find_transitive_override(super_klass, 397 target_method, i, target_loader, 398 target_classname, THREAD)) 399 != (InstanceKlass*)NULL)))) 400 { 401 // overriding, so no new entry 402 allocate_new = false; 403 404 if (checkconstraints) { 405 // Override vtable entry if passes loader constraint check 406 // if loader constraint checking requested 407 // No need to visit his super, since he and his super 408 // have already made any needed loader constraints. 409 // Since loader constraints are transitive, it is enough 410 // to link to the first super, and we get all the others. 411 Handle super_loader(THREAD, super_klass->class_loader()); 412 413 if (target_loader() != super_loader()) { 414 ResourceMark rm(THREAD); 415 Symbol* failed_type_symbol = 416 SystemDictionary::check_signature_loaders(signature, target_loader, 417 super_loader, true, 418 CHECK_(false)); 419 if (failed_type_symbol != NULL) { 420 const char* msg = "loader constraint violation: when resolving " 421 "overridden method \"%s\" the class loader (instance" 422 " of %s) of the current class, %s, and its superclass loader " 423 "(instance of %s), have different Class objects for the type " 424 "%s used in the signature"; 425 char* sig = target_method()->name_and_sig_as_C_string(); 426 const char* loader1 = SystemDictionary::loader_name(target_loader()); 427 char* current = target_klass->name()->as_C_string(); 428 const char* loader2 = SystemDictionary::loader_name(super_loader()); 429 char* failed_type_name = failed_type_symbol->as_C_string(); 430 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) + 431 strlen(current) + strlen(loader2) + strlen(failed_type_name); 432 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen); 433 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2, 434 failed_type_name); 435 THROW_MSG_(vmSymbols::java_lang_LinkageError(), buf, false); 436 } 437 } 438 } 439 440 put_method_at(target_method(), i); 441 if (!is_default) { 442 target_method()->set_vtable_index(i); 443 } else { 444 if (def_vtable_indices != NULL) { 445 def_vtable_indices->at_put(default_index, i); 446 } 447 assert(super_method->is_default_method() || super_method->is_overpass() 448 || super_method->is_abstract(), "default override error"); 449 } 450 451 452#ifndef PRODUCT 453 if (PrintVtables && Verbose) { 454 ResourceMark rm(THREAD); 455 char* sig = target_method()->name_and_sig_as_C_string(); 456 tty->print("overriding with %s::%s index %d, original flags: ", 457 target_klass->internal_name(), sig, i); 458 super_method->access_flags().print_on(tty); 459 if (super_method->is_default_method()) { 460 tty->print("default "); 461 } 462 if (super_method->is_overpass()) { 463 tty->print("overpass"); 464 } 465 tty->print("overriders flags: "); 466 target_method->access_flags().print_on(tty); 467 if (target_method->is_default_method()) { 468 tty->print("default "); 469 } 470 if (target_method->is_overpass()) { 471 tty->print("overpass"); 472 } 473 tty->cr(); 474 } 475#endif /*PRODUCT*/ 476 } else { 477 // allocate_new = true; default. We might override one entry, 478 // but not override another. Once we override one, not need new 479#ifndef PRODUCT 480 if (PrintVtables && Verbose) { 481 ResourceMark rm(THREAD); 482 char* sig = target_method()->name_and_sig_as_C_string(); 483 tty->print("NOT overriding with %s::%s index %d, original flags: ", 484 target_klass->internal_name(), sig,i); 485 super_method->access_flags().print_on(tty); 486 if (super_method->is_default_method()) { 487 tty->print("default "); 488 } 489 if (super_method->is_overpass()) { 490 tty->print("overpass"); 491 } 492 tty->print("overriders flags: "); 493 target_method->access_flags().print_on(tty); 494 if (target_method->is_default_method()) { 495 tty->print("default "); 496 } 497 if (target_method->is_overpass()) { 498 tty->print("overpass"); 499 } 500 tty->cr(); 501 } 502#endif /*PRODUCT*/ 503 } 504 } 505 } 506 return allocate_new; 507} 508 509void klassVtable::put_method_at(Method* m, int index) { 510#ifndef PRODUCT 511 if (PrintVtables && Verbose) { 512 ResourceMark rm; 513 const char* sig = (m != NULL) ? m->name_and_sig_as_C_string() : "<NULL>"; 514 tty->print("adding %s at index %d, flags: ", sig, index); 515 if (m != NULL) { 516 m->access_flags().print_on(tty); 517 if (m->is_default_method()) { 518 tty->print("default "); 519 } 520 if (m->is_overpass()) { 521 tty->print("overpass"); 522 } 523 } 524 tty->cr(); 525 } 526#endif 527 table()[index].set(m); 528} 529 530// Find out if a method "m" with superclass "super", loader "classloader" and 531// name "classname" needs a new vtable entry. Let P be a class package defined 532// by "classloader" and "classname". 533// NOTE: The logic used here is very similar to the one used for computing 534// the vtables indices for a method. We cannot directly use that function because, 535// we allocate the InstanceKlass at load time, and that requires that the 536// superclass has been loaded. 537// However, the vtable entries are filled in at link time, and therefore 538// the superclass' vtable may not yet have been filled in. 539bool klassVtable::needs_new_vtable_entry(methodHandle target_method, 540 Klass* super, 541 Handle classloader, 542 Symbol* classname, 543 AccessFlags class_flags, 544 TRAPS) { 545 if (class_flags.is_interface()) { 546 // Interfaces do not use vtables, so there is no point to assigning 547 // a vtable index to any of their methods. If we refrain from doing this, 548 // we can use Method::_vtable_index to hold the itable index 549 return false; 550 } 551 552 if (target_method->is_final_method(class_flags) || 553 // a final method never needs a new entry; final methods can be statically 554 // resolved and they have to be present in the vtable only if they override 555 // a super's method, in which case they re-use its entry 556 (target_method()->is_static()) || 557 // static methods don't need to be in vtable 558 (target_method()->name() == vmSymbols::object_initializer_name()) 559 // <init> is never called dynamically-bound 560 ) { 561 return false; 562 } 563 564 // Concrete interface methods do not need new entries, they override 565 // abstract method entries using default inheritance rules 566 if (target_method()->method_holder() != NULL && 567 target_method()->method_holder()->is_interface() && 568 !target_method()->is_abstract() ) { 569 return false; 570 } 571 572 // we need a new entry if there is no superclass 573 if (super == NULL) { 574 return true; 575 } 576 577 // private methods in classes always have a new entry in the vtable 578 // specification interpretation since classic has 579 // private methods not overriding 580 // JDK8 adds private methods in interfaces which require invokespecial 581 if (target_method()->is_private()) { 582 return true; 583 } 584 585 // search through the super class hierarchy to see if we need 586 // a new entry 587 ResourceMark rm; 588 Symbol* name = target_method()->name(); 589 Symbol* signature = target_method()->signature(); 590 Klass* k = super; 591 Method* super_method = NULL; 592 InstanceKlass *holder = NULL; 593 Method* recheck_method = NULL; 594 while (k != NULL) { 595 // lookup through the hierarchy for a method with matching name and sign. 596 super_method = InstanceKlass::cast(k)->lookup_method(name, signature); 597 if (super_method == NULL) { 598 break; // we still have to search for a matching miranda method 599 } 600 // get the class holding the matching method 601 // make sure you use that class for is_override 602 InstanceKlass* superk = super_method->method_holder(); 603 // we want only instance method matches 604 // pretend private methods are not in the super vtable 605 // since we do override around them: e.g. a.m pub/b.m private/c.m pub, 606 // ignore private, c.m pub does override a.m pub 607 // For classes that were not javac'd together, we also do transitive overriding around 608 // methods that have less accessibility 609 if ((!super_method->is_static()) && 610 (!super_method->is_private())) { 611 if (superk->is_override(super_method, classloader, classname, THREAD)) { 612 return false; 613 // else keep looking for transitive overrides 614 } 615 } 616 617 // Start with lookup result and continue to search up 618 k = superk->super(); // haven't found an override match yet; continue to look 619 } 620 621 // if the target method is public or protected it may have a matching 622 // miranda method in the super, whose entry it should re-use. 623 // Actually, to handle cases that javac would not generate, we need 624 // this check for all access permissions. 625 InstanceKlass *sk = InstanceKlass::cast(super); 626 if (sk->has_miranda_methods()) { 627 if (sk->lookup_method_in_all_interfaces(name, signature, Klass::normal) != NULL) { 628 return false; // found a matching miranda; we do not need a new entry 629 } 630 } 631 return true; // found no match; we need a new entry 632} 633 634// Support for miranda methods 635 636// get the vtable index of a miranda method with matching "name" and "signature" 637int klassVtable::index_of_miranda(Symbol* name, Symbol* signature) { 638 // search from the bottom, might be faster 639 for (int i = (length() - 1); i >= 0; i--) { 640 Method* m = table()[i].method(); 641 if (is_miranda_entry_at(i) && 642 m->name() == name && m->signature() == signature) { 643 return i; 644 } 645 } 646 return Method::invalid_vtable_index; 647} 648 649// check if an entry at an index is miranda 650// requires that method m at entry be declared ("held") by an interface. 651bool klassVtable::is_miranda_entry_at(int i) { 652 Method* m = method_at(i); 653 Klass* method_holder = m->method_holder(); 654 InstanceKlass *mhk = InstanceKlass::cast(method_holder); 655 656 // miranda methods are public abstract instance interface methods in a class's vtable 657 if (mhk->is_interface()) { 658 assert(m->is_public(), "should be public"); 659 assert(ik()->implements_interface(method_holder) , "this class should implement the interface"); 660 // the search could find a miranda or a default method 661 if (is_miranda(m, ik()->methods(), ik()->default_methods(), ik()->super())) { 662 return true; 663 } 664 } 665 return false; 666} 667 668// check if a method is a miranda method, given a class's methods table, 669// its default_method table and its super 670// Miranda methods are calculated twice: 671// first: before vtable size calculation: including abstract and default 672// This is seen by default method creation 673// Second: recalculated during vtable initialization: only abstract 674// This is seen by link resolution and selection. 675// "miranda" means not static, not defined by this class. 676// private methods in interfaces do not belong in the miranda list. 677// the caller must make sure that the method belongs to an interface implemented by the class 678// Miranda methods only include public interface instance methods 679// Not private methods, not static methods, not default == concrete abstract 680// Miranda methods also do not include overpass methods in interfaces 681bool klassVtable::is_miranda(Method* m, Array<Method*>* class_methods, 682 Array<Method*>* default_methods, Klass* super) { 683 if (m->is_static() || m->is_private() || m->is_overpass()) { 684 return false; 685 } 686 Symbol* name = m->name(); 687 Symbol* signature = m->signature(); 688 689 if (InstanceKlass::find_instance_method(class_methods, name, signature) == NULL) { 690 // did not find it in the method table of the current class 691 if ((default_methods == NULL) || 692 InstanceKlass::find_method(default_methods, name, signature) == NULL) { 693 if (super == NULL) { 694 // super doesn't exist 695 return true; 696 } 697 698 Method* mo = InstanceKlass::cast(super)->lookup_method(name, signature); 699 while (mo != NULL && mo->access_flags().is_static() 700 && mo->method_holder() != NULL 701 && mo->method_holder()->super() != NULL) 702 { 703 mo = mo->method_holder()->super()->uncached_lookup_method(name, signature, Klass::normal); 704 } 705 if (mo == NULL || mo->access_flags().is_private() ) { 706 // super class hierarchy does not implement it or protection is different 707 return true; 708 } 709 } 710 } 711 712 return false; 713} 714 715// Scans current_interface_methods for miranda methods that do not 716// already appear in new_mirandas, or default methods, and are also not defined-and-non-private 717// in super (superclass). These mirandas are added to all_mirandas if it is 718// not null; in addition, those that are not duplicates of miranda methods 719// inherited by super from its interfaces are added to new_mirandas. 720// Thus, new_mirandas will be the set of mirandas that this class introduces, 721// all_mirandas will be the set of all mirandas applicable to this class 722// including all defined in superclasses. 723void klassVtable::add_new_mirandas_to_lists( 724 GrowableArray<Method*>* new_mirandas, GrowableArray<Method*>* all_mirandas, 725 Array<Method*>* current_interface_methods, Array<Method*>* class_methods, 726 Array<Method*>* default_methods, Klass* super) { 727 728 // iterate thru the current interface's method to see if it a miranda 729 int num_methods = current_interface_methods->length(); 730 for (int i = 0; i < num_methods; i++) { 731 Method* im = current_interface_methods->at(i); 732 bool is_duplicate = false; 733 int num_of_current_mirandas = new_mirandas->length(); 734 // check for duplicate mirandas in different interfaces we implement 735 for (int j = 0; j < num_of_current_mirandas; j++) { 736 Method* miranda = new_mirandas->at(j); 737 if ((im->name() == miranda->name()) && 738 (im->signature() == miranda->signature())) { 739 is_duplicate = true; 740 break; 741 } 742 } 743 744 if (!is_duplicate) { // we don't want duplicate miranda entries in the vtable 745 if (is_miranda(im, class_methods, default_methods, super)) { // is it a miranda at all? 746 InstanceKlass *sk = InstanceKlass::cast(super); 747 // check if it is a duplicate of a super's miranda 748 if (sk->lookup_method_in_all_interfaces(im->name(), im->signature(), Klass::normal) == NULL) { 749 new_mirandas->append(im); 750 } 751 if (all_mirandas != NULL) { 752 all_mirandas->append(im); 753 } 754 } 755 } 756 } 757} 758 759void klassVtable::get_mirandas(GrowableArray<Method*>* new_mirandas, 760 GrowableArray<Method*>* all_mirandas, 761 Klass* super, Array<Method*>* class_methods, 762 Array<Method*>* default_methods, 763 Array<Klass*>* local_interfaces) { 764 assert((new_mirandas->length() == 0) , "current mirandas must be 0"); 765 766 // iterate thru the local interfaces looking for a miranda 767 int num_local_ifs = local_interfaces->length(); 768 for (int i = 0; i < num_local_ifs; i++) { 769 InstanceKlass *ik = InstanceKlass::cast(local_interfaces->at(i)); 770 add_new_mirandas_to_lists(new_mirandas, all_mirandas, 771 ik->methods(), class_methods, 772 default_methods, super); 773 // iterate thru each local's super interfaces 774 Array<Klass*>* super_ifs = ik->transitive_interfaces(); 775 int num_super_ifs = super_ifs->length(); 776 for (int j = 0; j < num_super_ifs; j++) { 777 InstanceKlass *sik = InstanceKlass::cast(super_ifs->at(j)); 778 add_new_mirandas_to_lists(new_mirandas, all_mirandas, 779 sik->methods(), class_methods, 780 default_methods, super); 781 } 782 } 783} 784 785// Discover miranda methods ("miranda" = "interface abstract, no binding"), 786// and append them into the vtable starting at index initialized, 787// return the new value of initialized. 788// Miranda methods use vtable entries, but do not get assigned a vtable_index 789// The vtable_index is discovered by searching from the end of the vtable 790int klassVtable::fill_in_mirandas(int initialized) { 791 GrowableArray<Method*> mirandas(20); 792 get_mirandas(&mirandas, NULL, ik()->super(), ik()->methods(), 793 ik()->default_methods(), ik()->local_interfaces()); 794 for (int i = 0; i < mirandas.length(); i++) { 795 if (PrintVtables && Verbose) { 796 Method* meth = mirandas.at(i); 797 ResourceMark rm(Thread::current()); 798 if (meth != NULL) { 799 char* sig = meth->name_and_sig_as_C_string(); 800 tty->print("fill in mirandas with %s index %d, flags: ", 801 sig, initialized); 802 meth->access_flags().print_on(tty); 803 if (meth->is_default_method()) { 804 tty->print("default "); 805 } 806 tty->cr(); 807 } 808 } 809 put_method_at(mirandas.at(i), initialized); 810 ++initialized; 811 } 812 return initialized; 813} 814 815// Copy this class's vtable to the vtable beginning at start. 816// Used to copy superclass vtable to prefix of subclass's vtable. 817void klassVtable::copy_vtable_to(vtableEntry* start) { 818 Copy::disjoint_words((HeapWord*)table(), (HeapWord*)start, _length * vtableEntry::size()); 819} 820 821#if INCLUDE_JVMTI 822bool klassVtable::adjust_default_method(int vtable_index, Method* old_method, Method* new_method) { 823 // If old_method is default, find this vtable index in default_vtable_indices 824 // and replace that method in the _default_methods list 825 bool updated = false; 826 827 Array<Method*>* default_methods = ik()->default_methods(); 828 if (default_methods != NULL) { 829 int len = default_methods->length(); 830 for (int idx = 0; idx < len; idx++) { 831 if (vtable_index == ik()->default_vtable_indices()->at(idx)) { 832 if (default_methods->at(idx) == old_method) { 833 default_methods->at_put(idx, new_method); 834 updated = true; 835 } 836 break; 837 } 838 } 839 } 840 return updated; 841} 842void klassVtable::adjust_method_entries(Method** old_methods, Method** new_methods, 843 int methods_length, bool * trace_name_printed) { 844 // search the vtable for uses of either obsolete or EMCP methods 845 for (int j = 0; j < methods_length; j++) { 846 Method* old_method = old_methods[j]; 847 Method* new_method = new_methods[j]; 848 849 // In the vast majority of cases we could get the vtable index 850 // by using: old_method->vtable_index() 851 // However, there are rare cases, eg. sun.awt.X11.XDecoratedPeer.getX() 852 // in sun.awt.X11.XFramePeer where methods occur more than once in the 853 // vtable, so, alas, we must do an exhaustive search. 854 for (int index = 0; index < length(); index++) { 855 if (unchecked_method_at(index) == old_method) { 856 put_method_at(new_method, index); 857 // For default methods, need to update the _default_methods array 858 // which can only have one method entry for a given signature 859 bool updated_default = false; 860 if (old_method->is_default_method()) { 861 updated_default = adjust_default_method(index, old_method, new_method); 862 } 863 864 if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) { 865 if (!(*trace_name_printed)) { 866 // RC_TRACE_MESG macro has an embedded ResourceMark 867 RC_TRACE_MESG(("adjust: klassname=%s for methods from name=%s", 868 klass()->external_name(), 869 old_method->method_holder()->external_name())); 870 *trace_name_printed = true; 871 } 872 // RC_TRACE macro has an embedded ResourceMark 873 RC_TRACE(0x00100000, ("vtable method update: %s(%s), updated default = %s", 874 new_method->name()->as_C_string(), 875 new_method->signature()->as_C_string(), 876 updated_default ? "true" : "false")); 877 } 878 // cannot 'break' here; see for-loop comment above. 879 } 880 } 881 } 882} 883 884// a vtable should never contain old or obsolete methods 885bool klassVtable::check_no_old_or_obsolete_entries() { 886 for (int i = 0; i < length(); i++) { 887 Method* m = unchecked_method_at(i); 888 if (m != NULL && 889 (NOT_PRODUCT(!m->is_valid() ||) m->is_old() || m->is_obsolete())) { 890 return false; 891 } 892 } 893 return true; 894} 895 896void klassVtable::dump_vtable() { 897 tty->print_cr("vtable dump --"); 898 for (int i = 0; i < length(); i++) { 899 Method* m = unchecked_method_at(i); 900 if (m != NULL) { 901 tty->print(" (%5d) ", i); 902 m->access_flags().print_on(tty); 903 if (m->is_default_method()) { 904 tty->print("default "); 905 } 906 if (m->is_overpass()) { 907 tty->print("overpass"); 908 } 909 tty->print(" -- "); 910 m->print_name(tty); 911 tty->cr(); 912 } 913 } 914} 915#endif // INCLUDE_JVMTI 916 917// CDS/RedefineClasses support - clear vtables so they can be reinitialized 918void klassVtable::clear_vtable() { 919 for (int i = 0; i < _length; i++) table()[i].clear(); 920} 921 922bool klassVtable::is_initialized() { 923 return _length == 0 || table()[0].method() != NULL; 924} 925 926//----------------------------------------------------------------------------------------- 927// Itable code 928 929// Initialize a itableMethodEntry 930void itableMethodEntry::initialize(Method* m) { 931 if (m == NULL) return; 932 933 _method = m; 934} 935 936klassItable::klassItable(instanceKlassHandle klass) { 937 _klass = klass; 938 939 if (klass->itable_length() > 0) { 940 itableOffsetEntry* offset_entry = (itableOffsetEntry*)klass->start_of_itable(); 941 if (offset_entry != NULL && offset_entry->interface_klass() != NULL) { // Check that itable is initialized 942 // First offset entry points to the first method_entry 943 intptr_t* method_entry = (intptr_t *)(((address)klass()) + offset_entry->offset()); 944 intptr_t* end = klass->end_of_itable(); 945 946 _table_offset = (intptr_t*)offset_entry - (intptr_t*)klass(); 947 _size_offset_table = (method_entry - ((intptr_t*)offset_entry)) / itableOffsetEntry::size(); 948 _size_method_table = (end - method_entry) / itableMethodEntry::size(); 949 assert(_table_offset >= 0 && _size_offset_table >= 0 && _size_method_table >= 0, "wrong computation"); 950 return; 951 } 952 } 953 954 // The length of the itable was either zero, or it has not yet been initialized. 955 _table_offset = 0; 956 _size_offset_table = 0; 957 _size_method_table = 0; 958} 959 960static int initialize_count = 0; 961 962// Initialization 963void klassItable::initialize_itable(bool checkconstraints, TRAPS) { 964 if (_klass->is_interface()) { 965 // This needs to go after vtable indices are assigned but 966 // before implementors need to know the number of itable indices. 967 assign_itable_indices_for_interface(_klass()); 968 } 969 970 // Cannot be setup doing bootstrapping, interfaces don't have 971 // itables, and klass with only ones entry have empty itables 972 if (Universe::is_bootstrapping() || 973 _klass->is_interface() || 974 _klass->itable_length() == itableOffsetEntry::size()) return; 975 976 // There's alway an extra itable entry so we can null-terminate it. 977 guarantee(size_offset_table() >= 1, "too small"); 978 int num_interfaces = size_offset_table() - 1; 979 if (num_interfaces > 0) { 980 if (TraceItables) tty->print_cr("%3d: Initializing itables for %s", ++initialize_count, 981 _klass->name()->as_C_string()); 982 983 984 // Iterate through all interfaces 985 int i; 986 for(i = 0; i < num_interfaces; i++) { 987 itableOffsetEntry* ioe = offset_entry(i); 988 HandleMark hm(THREAD); 989 KlassHandle interf_h (THREAD, ioe->interface_klass()); 990 assert(interf_h() != NULL && ioe->offset() != 0, "bad offset entry in itable"); 991 initialize_itable_for_interface(ioe->offset(), interf_h, checkconstraints, CHECK); 992 } 993 994 } 995 // Check that the last entry is empty 996 itableOffsetEntry* ioe = offset_entry(size_offset_table() - 1); 997 guarantee(ioe->interface_klass() == NULL && ioe->offset() == 0, "terminator entry missing"); 998} 999 1000 1001inline bool interface_method_needs_itable_index(Method* m) { 1002 if (m->is_static()) return false; // e.g., Stream.empty 1003 if (m->is_initializer()) return false; // <init> or <clinit> 1004 // If an interface redeclares a method from java.lang.Object, 1005 // it should already have a vtable index, don't touch it. 1006 // e.g., CharSequence.toString (from initialize_vtable) 1007 // if (m->has_vtable_index()) return false; // NO! 1008 return true; 1009} 1010 1011int klassItable::assign_itable_indices_for_interface(Klass* klass) { 1012 // an interface does not have an itable, but its methods need to be numbered 1013 if (TraceItables) tty->print_cr("%3d: Initializing itable for interface %s", ++initialize_count, 1014 klass->name()->as_C_string()); 1015 Array<Method*>* methods = InstanceKlass::cast(klass)->methods(); 1016 int nof_methods = methods->length(); 1017 int ime_num = 0; 1018 for (int i = 0; i < nof_methods; i++) { 1019 Method* m = methods->at(i); 1020 if (interface_method_needs_itable_index(m)) { 1021 assert(!m->is_final_method(), "no final interface methods"); 1022 // If m is already assigned a vtable index, do not disturb it. 1023 if (TraceItables && Verbose) { 1024 ResourceMark rm; 1025 const char* sig = (m != NULL) ? m->name_and_sig_as_C_string() : "<NULL>"; 1026 if (m->has_vtable_index()) { 1027 tty->print("itable index %d for method: %s, flags: ", m->vtable_index(), sig); 1028 } else { 1029 tty->print("itable index %d for method: %s, flags: ", ime_num, sig); 1030 } 1031 if (m != NULL) { 1032 m->access_flags().print_on(tty); 1033 if (m->is_default_method()) { 1034 tty->print("default "); 1035 } 1036 if (m->is_overpass()) { 1037 tty->print("overpass"); 1038 } 1039 } 1040 tty->cr(); 1041 } 1042 if (!m->has_vtable_index()) { 1043 assert(m->vtable_index() == Method::pending_itable_index, "set by initialize_vtable"); 1044 m->set_itable_index(ime_num); 1045 // Progress to next itable entry 1046 ime_num++; 1047 } 1048 } 1049 } 1050 assert(ime_num == method_count_for_interface(klass), "proper sizing"); 1051 return ime_num; 1052} 1053 1054int klassItable::method_count_for_interface(Klass* interf) { 1055 assert(interf->oop_is_instance(), "must be"); 1056 assert(interf->is_interface(), "must be"); 1057 Array<Method*>* methods = InstanceKlass::cast(interf)->methods(); 1058 int nof_methods = methods->length(); 1059 while (nof_methods > 0) { 1060 Method* m = methods->at(nof_methods-1); 1061 if (m->has_itable_index()) { 1062 int length = m->itable_index() + 1; 1063#ifdef ASSERT 1064 while (nof_methods = 0) { 1065 m = methods->at(--nof_methods); 1066 assert(!m->has_itable_index() || m->itable_index() < length, ""); 1067 } 1068#endif //ASSERT 1069 return length; // return the rightmost itable index, plus one 1070 } 1071 nof_methods -= 1; 1072 } 1073 // no methods have itable indices 1074 return 0; 1075} 1076 1077 1078void klassItable::initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS) { 1079 Array<Method*>* methods = InstanceKlass::cast(interf_h())->methods(); 1080 int nof_methods = methods->length(); 1081 HandleMark hm; 1082 assert(nof_methods > 0, "at least one method must exist for interface to be in vtable"); 1083 Handle interface_loader (THREAD, InstanceKlass::cast(interf_h())->class_loader()); 1084 1085 int ime_count = method_count_for_interface(interf_h()); 1086 for (int i = 0; i < nof_methods; i++) { 1087 Method* m = methods->at(i); 1088 methodHandle target; 1089 if (m->has_itable_index()) { 1090 // This search must match the runtime resolution, i.e. selection search for invokeinterface 1091 // to correctly enforce loader constraints for interface method inheritance 1092 LinkResolver::lookup_instance_method_in_klasses(target, _klass, m->name(), m->signature(), CHECK); 1093 } 1094 if (target == NULL || !target->is_public() || target->is_abstract()) { 1095 // Entry does not resolve. Leave it empty for AbstractMethodError. 1096 if (!(target == NULL) && !target->is_public()) { 1097 // Stuff an IllegalAccessError throwing method in there instead. 1098 itableOffsetEntry::method_entry(_klass(), method_table_offset)[m->itable_index()]. 1099 initialize(Universe::throw_illegal_access_error()); 1100 } 1101 } else { 1102 // Entry did resolve, check loader constraints before initializing 1103 // if checkconstraints requested 1104 if (checkconstraints) { 1105 Handle method_holder_loader (THREAD, target->method_holder()->class_loader()); 1106 if (method_holder_loader() != interface_loader()) { 1107 ResourceMark rm(THREAD); 1108 Symbol* failed_type_symbol = 1109 SystemDictionary::check_signature_loaders(m->signature(), 1110 method_holder_loader, 1111 interface_loader, 1112 true, CHECK); 1113 if (failed_type_symbol != NULL) { 1114 const char* msg = "loader constraint violation in interface " 1115 "itable initialization: when resolving method \"%s\" the class" 1116 " loader (instance of %s) of the current class, %s, " 1117 "and the class loader (instance of %s) for interface " 1118 "%s have different Class objects for the type %s " 1119 "used in the signature"; 1120 char* sig = target()->name_and_sig_as_C_string(); 1121 const char* loader1 = SystemDictionary::loader_name(method_holder_loader()); 1122 char* current = _klass->name()->as_C_string(); 1123 const char* loader2 = SystemDictionary::loader_name(interface_loader()); 1124 char* iface = InstanceKlass::cast(interf_h())->name()->as_C_string(); 1125 char* failed_type_name = failed_type_symbol->as_C_string(); 1126 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) + 1127 strlen(current) + strlen(loader2) + strlen(iface) + 1128 strlen(failed_type_name); 1129 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen); 1130 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2, 1131 iface, failed_type_name); 1132 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf); 1133 } 1134 } 1135 } 1136 1137 // ime may have moved during GC so recalculate address 1138 int ime_num = m->itable_index(); 1139 assert(ime_num < ime_count, "oob"); 1140 itableOffsetEntry::method_entry(_klass(), method_table_offset)[ime_num].initialize(target()); 1141 if (TraceItables && Verbose) { 1142 ResourceMark rm(THREAD); 1143 if (target() != NULL) { 1144 char* sig = target()->name_and_sig_as_C_string(); 1145 tty->print("interface: %s, ime_num: %d, target: %s, method_holder: %s ", 1146 interf_h()->internal_name(), ime_num, sig, 1147 target()->method_holder()->internal_name()); 1148 tty->print("target_method flags: "); 1149 target()->access_flags().print_on(tty); 1150 if (target()->is_default_method()) { 1151 tty->print("default "); 1152 } 1153 tty->cr(); 1154 } 1155 } 1156 } 1157 } 1158} 1159 1160// Update entry for specific Method* 1161void klassItable::initialize_with_method(Method* m) { 1162 itableMethodEntry* ime = method_entry(0); 1163 for(int i = 0; i < _size_method_table; i++) { 1164 if (ime->method() == m) { 1165 ime->initialize(m); 1166 } 1167 ime++; 1168 } 1169} 1170 1171#if INCLUDE_JVMTI 1172void klassItable::adjust_method_entries(Method** old_methods, Method** new_methods, 1173 int methods_length, bool * trace_name_printed) { 1174 // search the itable for uses of either obsolete or EMCP methods 1175 for (int j = 0; j < methods_length; j++) { 1176 Method* old_method = old_methods[j]; 1177 Method* new_method = new_methods[j]; 1178 itableMethodEntry* ime = method_entry(0); 1179 1180 // The itable can describe more than one interface and the same 1181 // method signature can be specified by more than one interface. 1182 // This means we have to do an exhaustive search to find all the 1183 // old_method references. 1184 for (int i = 0; i < _size_method_table; i++) { 1185 if (ime->method() == old_method) { 1186 ime->initialize(new_method); 1187 1188 if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) { 1189 if (!(*trace_name_printed)) { 1190 // RC_TRACE_MESG macro has an embedded ResourceMark 1191 RC_TRACE_MESG(("adjust: name=%s", 1192 old_method->method_holder()->external_name())); 1193 *trace_name_printed = true; 1194 } 1195 // RC_TRACE macro has an embedded ResourceMark 1196 RC_TRACE(0x00200000, ("itable method update: %s(%s)", 1197 new_method->name()->as_C_string(), 1198 new_method->signature()->as_C_string())); 1199 } 1200 // cannot 'break' here; see for-loop comment above. 1201 } 1202 ime++; 1203 } 1204 } 1205} 1206 1207// an itable should never contain old or obsolete methods 1208bool klassItable::check_no_old_or_obsolete_entries() { 1209 itableMethodEntry* ime = method_entry(0); 1210 for (int i = 0; i < _size_method_table; i++) { 1211 Method* m = ime->method(); 1212 if (m != NULL && 1213 (NOT_PRODUCT(!m->is_valid() ||) m->is_old() || m->is_obsolete())) { 1214 return false; 1215 } 1216 ime++; 1217 } 1218 return true; 1219} 1220 1221void klassItable::dump_itable() { 1222 itableMethodEntry* ime = method_entry(0); 1223 tty->print_cr("itable dump --"); 1224 for (int i = 0; i < _size_method_table; i++) { 1225 Method* m = ime->method(); 1226 if (m != NULL) { 1227 tty->print(" (%5d) ", i); 1228 m->access_flags().print_on(tty); 1229 if (m->is_default_method()) { 1230 tty->print("default "); 1231 } 1232 tty->print(" -- "); 1233 m->print_name(tty); 1234 tty->cr(); 1235 } 1236 ime++; 1237 } 1238} 1239#endif // INCLUDE_JVMTI 1240 1241 1242// Setup 1243class InterfaceVisiterClosure : public StackObj { 1244 public: 1245 virtual void doit(Klass* intf, int method_count) = 0; 1246}; 1247 1248// Visit all interfaces with at least one itable method 1249void visit_all_interfaces(Array<Klass*>* transitive_intf, InterfaceVisiterClosure *blk) { 1250 // Handle array argument 1251 for(int i = 0; i < transitive_intf->length(); i++) { 1252 Klass* intf = transitive_intf->at(i); 1253 assert(intf->is_interface(), "sanity check"); 1254 1255 // Find no. of itable methods 1256 int method_count = 0; 1257 // method_count = klassItable::method_count_for_interface(intf); 1258 Array<Method*>* methods = InstanceKlass::cast(intf)->methods(); 1259 if (methods->length() > 0) { 1260 for (int i = methods->length(); --i >= 0; ) { 1261 if (interface_method_needs_itable_index(methods->at(i))) { 1262 method_count++; 1263 } 1264 } 1265 } 1266 1267 // Only count interfaces with at least one method 1268 if (method_count > 0) { 1269 blk->doit(intf, method_count); 1270 } 1271 } 1272} 1273 1274class CountInterfacesClosure : public InterfaceVisiterClosure { 1275 private: 1276 int _nof_methods; 1277 int _nof_interfaces; 1278 public: 1279 CountInterfacesClosure() { _nof_methods = 0; _nof_interfaces = 0; } 1280 1281 int nof_methods() const { return _nof_methods; } 1282 int nof_interfaces() const { return _nof_interfaces; } 1283 1284 void doit(Klass* intf, int method_count) { _nof_methods += method_count; _nof_interfaces++; } 1285}; 1286 1287class SetupItableClosure : public InterfaceVisiterClosure { 1288 private: 1289 itableOffsetEntry* _offset_entry; 1290 itableMethodEntry* _method_entry; 1291 address _klass_begin; 1292 public: 1293 SetupItableClosure(address klass_begin, itableOffsetEntry* offset_entry, itableMethodEntry* method_entry) { 1294 _klass_begin = klass_begin; 1295 _offset_entry = offset_entry; 1296 _method_entry = method_entry; 1297 } 1298 1299 itableMethodEntry* method_entry() const { return _method_entry; } 1300 1301 void doit(Klass* intf, int method_count) { 1302 int offset = ((address)_method_entry) - _klass_begin; 1303 _offset_entry->initialize(intf, offset); 1304 _offset_entry++; 1305 _method_entry += method_count; 1306 } 1307}; 1308 1309int klassItable::compute_itable_size(Array<Klass*>* transitive_interfaces) { 1310 // Count no of interfaces and total number of interface methods 1311 CountInterfacesClosure cic; 1312 visit_all_interfaces(transitive_interfaces, &cic); 1313 1314 // There's alway an extra itable entry so we can null-terminate it. 1315 int itable_size = calc_itable_size(cic.nof_interfaces() + 1, cic.nof_methods()); 1316 1317 // Statistics 1318 update_stats(itable_size * HeapWordSize); 1319 1320 return itable_size; 1321} 1322 1323 1324// Fill out offset table and interface klasses into the itable space 1325void klassItable::setup_itable_offset_table(instanceKlassHandle klass) { 1326 if (klass->itable_length() == 0) return; 1327 assert(!klass->is_interface(), "Should have zero length itable"); 1328 1329 // Count no of interfaces and total number of interface methods 1330 CountInterfacesClosure cic; 1331 visit_all_interfaces(klass->transitive_interfaces(), &cic); 1332 int nof_methods = cic.nof_methods(); 1333 int nof_interfaces = cic.nof_interfaces(); 1334 1335 // Add one extra entry so we can null-terminate the table 1336 nof_interfaces++; 1337 1338 assert(compute_itable_size(klass->transitive_interfaces()) == 1339 calc_itable_size(nof_interfaces, nof_methods), 1340 "mismatch calculation of itable size"); 1341 1342 // Fill-out offset table 1343 itableOffsetEntry* ioe = (itableOffsetEntry*)klass->start_of_itable(); 1344 itableMethodEntry* ime = (itableMethodEntry*)(ioe + nof_interfaces); 1345 intptr_t* end = klass->end_of_itable(); 1346 assert((oop*)(ime + nof_methods) <= (oop*)klass->start_of_nonstatic_oop_maps(), "wrong offset calculation (1)"); 1347 assert((oop*)(end) == (oop*)(ime + nof_methods), "wrong offset calculation (2)"); 1348 1349 // Visit all interfaces and initialize itable offset table 1350 SetupItableClosure sic((address)klass(), ioe, ime); 1351 visit_all_interfaces(klass->transitive_interfaces(), &sic); 1352 1353#ifdef ASSERT 1354 ime = sic.method_entry(); 1355 oop* v = (oop*) klass->end_of_itable(); 1356 assert( (oop*)(ime) == v, "wrong offset calculation (2)"); 1357#endif 1358} 1359 1360 1361// inverse to itable_index 1362Method* klassItable::method_for_itable_index(Klass* intf, int itable_index) { 1363 assert(InstanceKlass::cast(intf)->is_interface(), "sanity check"); 1364 assert(intf->verify_itable_index(itable_index), ""); 1365 Array<Method*>* methods = InstanceKlass::cast(intf)->methods(); 1366 1367 if (itable_index < 0 || itable_index >= method_count_for_interface(intf)) 1368 return NULL; // help caller defend against bad indices 1369 1370 int index = itable_index; 1371 Method* m = methods->at(index); 1372 int index2 = -1; 1373 while (!m->has_itable_index() || 1374 (index2 = m->itable_index()) != itable_index) { 1375 assert(index2 < itable_index, "monotonic"); 1376 if (++index == methods->length()) 1377 return NULL; 1378 m = methods->at(index); 1379 } 1380 assert(m->itable_index() == itable_index, "correct inverse"); 1381 1382 return m; 1383} 1384 1385void klassVtable::verify(outputStream* st, bool forced) { 1386 // make sure table is initialized 1387 if (!Universe::is_fully_initialized()) return; 1388#ifndef PRODUCT 1389 // avoid redundant verifies 1390 if (!forced && _verify_count == Universe::verify_count()) return; 1391 _verify_count = Universe::verify_count(); 1392#endif 1393 oop* end_of_obj = (oop*)_klass() + _klass()->size(); 1394 oop* end_of_vtable = (oop *)&table()[_length]; 1395 if (end_of_vtable > end_of_obj) { 1396 fatal(err_msg("klass %s: klass object too short (vtable extends beyond " 1397 "end)", _klass->internal_name())); 1398 } 1399 1400 for (int i = 0; i < _length; i++) table()[i].verify(this, st); 1401 // verify consistency with superKlass vtable 1402 Klass* super = _klass->super(); 1403 if (super != NULL) { 1404 InstanceKlass* sk = InstanceKlass::cast(super); 1405 klassVtable* vt = sk->vtable(); 1406 for (int i = 0; i < vt->length(); i++) { 1407 verify_against(st, vt, i); 1408 } 1409 } 1410} 1411 1412void klassVtable::verify_against(outputStream* st, klassVtable* vt, int index) { 1413 vtableEntry* vte = &vt->table()[index]; 1414 if (vte->method()->name() != table()[index].method()->name() || 1415 vte->method()->signature() != table()[index].method()->signature()) { 1416 fatal("mismatched name/signature of vtable entries"); 1417 } 1418} 1419 1420#ifndef PRODUCT 1421void klassVtable::print() { 1422 ResourceMark rm; 1423 tty->print("klassVtable for klass %s (length %d):\n", _klass->internal_name(), length()); 1424 for (int i = 0; i < length(); i++) { 1425 table()[i].print(); 1426 tty->cr(); 1427 } 1428} 1429#endif 1430 1431void vtableEntry::verify(klassVtable* vt, outputStream* st) { 1432 NOT_PRODUCT(FlagSetting fs(IgnoreLockingAssertions, true)); 1433 assert(method() != NULL, "must have set method"); 1434 method()->verify(); 1435 // we sub_type, because it could be a miranda method 1436 if (!vt->klass()->is_subtype_of(method()->method_holder())) { 1437#ifndef PRODUCT 1438 print(); 1439#endif 1440 fatal(err_msg("vtableEntry " PTR_FORMAT ": method is from subclass", this)); 1441 } 1442} 1443 1444#ifndef PRODUCT 1445 1446void vtableEntry::print() { 1447 ResourceMark rm; 1448 tty->print("vtableEntry %s: ", method()->name()->as_C_string()); 1449 if (Verbose) { 1450 tty->print("m %#lx ", (address)method()); 1451 } 1452} 1453 1454class VtableStats : AllStatic { 1455 public: 1456 static int no_klasses; // # classes with vtables 1457 static int no_array_klasses; // # array classes 1458 static int no_instance_klasses; // # instanceKlasses 1459 static int sum_of_vtable_len; // total # of vtable entries 1460 static int sum_of_array_vtable_len; // total # of vtable entries in array klasses only 1461 static int fixed; // total fixed overhead in bytes 1462 static int filler; // overhead caused by filler bytes 1463 static int entries; // total bytes consumed by vtable entries 1464 static int array_entries; // total bytes consumed by array vtable entries 1465 1466 static void do_class(Klass* k) { 1467 Klass* kl = k; 1468 klassVtable* vt = kl->vtable(); 1469 if (vt == NULL) return; 1470 no_klasses++; 1471 if (kl->oop_is_instance()) { 1472 no_instance_klasses++; 1473 kl->array_klasses_do(do_class); 1474 } 1475 if (kl->oop_is_array()) { 1476 no_array_klasses++; 1477 sum_of_array_vtable_len += vt->length(); 1478 } 1479 sum_of_vtable_len += vt->length(); 1480 } 1481 1482 static void compute() { 1483 SystemDictionary::classes_do(do_class); 1484 fixed = no_klasses * oopSize; // vtable length 1485 // filler size is a conservative approximation 1486 filler = oopSize * (no_klasses - no_instance_klasses) * (sizeof(InstanceKlass) - sizeof(ArrayKlass) - 1); 1487 entries = sizeof(vtableEntry) * sum_of_vtable_len; 1488 array_entries = sizeof(vtableEntry) * sum_of_array_vtable_len; 1489 } 1490}; 1491 1492int VtableStats::no_klasses = 0; 1493int VtableStats::no_array_klasses = 0; 1494int VtableStats::no_instance_klasses = 0; 1495int VtableStats::sum_of_vtable_len = 0; 1496int VtableStats::sum_of_array_vtable_len = 0; 1497int VtableStats::fixed = 0; 1498int VtableStats::filler = 0; 1499int VtableStats::entries = 0; 1500int VtableStats::array_entries = 0; 1501 1502void klassVtable::print_statistics() { 1503 ResourceMark rm; 1504 HandleMark hm; 1505 VtableStats::compute(); 1506 tty->print_cr("vtable statistics:"); 1507 tty->print_cr("%6d classes (%d instance, %d array)", VtableStats::no_klasses, VtableStats::no_instance_klasses, VtableStats::no_array_klasses); 1508 int total = VtableStats::fixed + VtableStats::filler + VtableStats::entries; 1509 tty->print_cr("%6d bytes fixed overhead (refs + vtable object header)", VtableStats::fixed); 1510 tty->print_cr("%6d bytes filler overhead", VtableStats::filler); 1511 tty->print_cr("%6d bytes for vtable entries (%d for arrays)", VtableStats::entries, VtableStats::array_entries); 1512 tty->print_cr("%6d bytes total", total); 1513} 1514 1515int klassItable::_total_classes; // Total no. of classes with itables 1516long klassItable::_total_size; // Total no. of bytes used for itables 1517 1518void klassItable::print_statistics() { 1519 tty->print_cr("itable statistics:"); 1520 tty->print_cr("%6d classes with itables", _total_classes); 1521 tty->print_cr("%6d K uses for itables (average by class: %d bytes)", _total_size / K, _total_size / _total_classes); 1522} 1523 1524#endif // PRODUCT 1525