1 /* 2 * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "classfile/systemDictionary.hpp" 27 #include "classfile/vmSymbols.hpp" 28 #include "gc/shared/gcLocker.hpp" 29 #include "logging/log.hpp" 30 #include "memory/resourceArea.hpp" 31 #include "memory/universe.inline.hpp" 32 #include "oops/instanceKlass.hpp" 33 #include "oops/klassVtable.hpp" 34 #include "oops/method.hpp" 35 #include "oops/objArrayOop.hpp" 36 #include "oops/oop.inline.hpp" 37 #include "prims/jvmtiRedefineClassesTrace.hpp" 38 #include "runtime/arguments.hpp" 39 #include "runtime/handles.inline.hpp" 40 #include "utilities/copy.hpp" 41 42 inline InstanceKlass* klassVtable::ik() const { 43 return InstanceKlass::cast(_klass()); 44 } 45 46 47 // this function computes the vtable size (including the size needed for miranda 48 // methods) and the number of miranda methods in this class. 49 // Note on Miranda methods: Let's say there is a class C that implements 50 // interface I, and none of C's superclasses implements I. 51 // Let's say there is an abstract method m in I that neither C 52 // nor any of its super classes implement (i.e there is no method of any access, 53 // with the same name and signature as m), then m is a Miranda method which is 54 // entered as a public abstract method in C's vtable. From then on it should 55 // treated as any other public method in C for method over-ride purposes. 56 void klassVtable::compute_vtable_size_and_num_mirandas( 57 int* vtable_length_ret, int* num_new_mirandas, 58 GrowableArray<Method*>* all_mirandas, const Klass* super, 59 Array<Method*>* methods, AccessFlags class_flags, 60 Handle classloader, Symbol* classname, Array<Klass*>* local_interfaces, 61 TRAPS) { 62 No_Safepoint_Verifier nsv; 63 64 // set up default result values 65 int vtable_length = 0; 66 67 // start off with super's vtable length 68 vtable_length = super == NULL ? 0 : super->vtable_length(); 69 70 // go thru each method in the methods table to see if it needs a new entry 71 int len = methods->length(); 72 for (int i = 0; i < len; i++) { 73 assert(methods->at(i)->is_method(), "must be a Method*"); 74 methodHandle mh(THREAD, methods->at(i)); 75 76 if (needs_new_vtable_entry(mh, super, classloader, classname, class_flags, THREAD)) { 77 vtable_length += vtableEntry::size(); // we need a new entry 78 } 79 } 80 81 GrowableArray<Method*> new_mirandas(20); 82 // compute the number of mirandas methods that must be added to the end 83 get_mirandas(&new_mirandas, all_mirandas, super, methods, NULL, local_interfaces); 84 *num_new_mirandas = new_mirandas.length(); 85 86 // Interfaces do not need interface methods in their vtables 87 // This includes miranda methods and during later processing, default methods 88 if (!class_flags.is_interface()) { 89 vtable_length += *num_new_mirandas * vtableEntry::size(); 90 } 91 92 if (Universe::is_bootstrapping() && vtable_length == 0) { 93 // array classes don't have their superclass set correctly during 94 // bootstrapping 95 vtable_length = Universe::base_vtable_size(); 96 } 97 98 if (super == NULL && vtable_length != Universe::base_vtable_size()) { 99 if (Universe::is_bootstrapping()) { 100 // Someone is attempting to override java.lang.Object incorrectly on the 101 // bootclasspath. The JVM cannot recover from this error including throwing 102 // an exception 103 vm_exit_during_initialization("Incompatible definition of java.lang.Object"); 104 } else { 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 } 113 assert(vtable_length % vtableEntry::size() == 0, "bad vtable length"); 114 assert(vtable_length >= Universe::base_vtable_size(), "vtable too small"); 115 116 *vtable_length_ret = vtable_length; 117 } 118 119 int klassVtable::index_of(Method* m, int len) const { 120 assert(m->has_vtable_index(), "do not ask this of non-vtable methods"); 121 return m->vtable_index(); 122 } 123 124 // Copy super class's vtable to the first part (prefix) of this class's vtable, 125 // and return the number of entries copied. Expects that 'super' is the Java 126 // super class (arrays can have "array" super classes that must be skipped). 127 int klassVtable::initialize_from_super(KlassHandle super) { 128 if (super.is_null()) { 129 return 0; 130 } else { 131 // copy methods from superKlass 132 klassVtable* superVtable = super->vtable(); 133 assert(superVtable->length() <= _length, "vtable too short"); 134 #ifdef ASSERT 135 superVtable->verify(tty, true); 136 #endif 137 superVtable->copy_vtable_to(table()); 138 if (develop_log_is_enabled(Trace, vtables)) { 139 ResourceMark rm; 140 log_develop_trace(vtables)("copy vtable from %s to %s size %d", 141 super->internal_name(), klass()->internal_name(), 142 _length); 143 } 144 return superVtable->length(); 145 } 146 } 147 148 // 149 // Revised lookup semantics introduced 1.3 (Kestrel beta) 150 void klassVtable::initialize_vtable(bool checkconstraints, TRAPS) { 151 152 // Note: Arrays can have intermediate array supers. Use java_super to skip them. 153 KlassHandle super (THREAD, klass()->java_super()); 154 int nofNewEntries = 0; 155 156 if (!klass()->is_array_klass()) { 157 ResourceMark rm(THREAD); 158 log_develop_debug(vtables)("Initializing: %s", _klass->name()->as_C_string()); 159 } 160 161 #ifdef ASSERT 162 oop* end_of_obj = (oop*)_klass() + _klass()->size(); 163 oop* end_of_vtable = (oop*)&table()[_length]; 164 assert(end_of_vtable <= end_of_obj, "vtable extends beyond end"); 165 #endif 166 167 if (Universe::is_bootstrapping()) { 168 // just clear everything 169 for (int i = 0; i < _length; i++) table()[i].clear(); 170 return; 171 } 172 173 int super_vtable_len = initialize_from_super(super); 174 if (klass()->is_array_klass()) { 175 assert(super_vtable_len == _length, "arrays shouldn't introduce new methods"); 176 } else { 177 assert(_klass->is_instance_klass(), "must be InstanceKlass"); 178 179 Array<Method*>* methods = ik()->methods(); 180 int len = methods->length(); 181 int initialized = super_vtable_len; 182 183 // Check each of this class's methods against super; 184 // if override, replace in copy of super vtable, otherwise append to end 185 for (int i = 0; i < len; i++) { 186 // update_inherited_vtable can stop for gc - ensure using handles 187 HandleMark hm(THREAD); 188 assert(methods->at(i)->is_method(), "must be a Method*"); 189 methodHandle mh(THREAD, methods->at(i)); 190 191 bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, -1, checkconstraints, CHECK); 192 193 if (needs_new_entry) { 194 put_method_at(mh(), initialized); 195 mh()->set_vtable_index(initialized); // set primary vtable index 196 initialized++; 197 } 198 } 199 200 // update vtable with default_methods 201 Array<Method*>* default_methods = ik()->default_methods(); 202 if (default_methods != NULL) { 203 len = default_methods->length(); 204 if (len > 0) { 205 Array<int>* def_vtable_indices = NULL; 206 if ((def_vtable_indices = ik()->default_vtable_indices()) == NULL) { 207 def_vtable_indices = ik()->create_new_default_vtable_indices(len, CHECK); 208 } else { 209 assert(def_vtable_indices->length() == len, "reinit vtable len?"); 210 } 211 for (int i = 0; i < len; i++) { 212 HandleMark hm(THREAD); 213 assert(default_methods->at(i)->is_method(), "must be a Method*"); 214 methodHandle mh(THREAD, default_methods->at(i)); 215 216 bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, i, checkconstraints, CHECK); 217 218 // needs new entry 219 if (needs_new_entry) { 220 put_method_at(mh(), initialized); 221 def_vtable_indices->at_put(i, initialized); //set vtable index 222 initialized++; 223 } 224 } 225 } 226 } 227 228 // add miranda methods; it will also return the updated initialized 229 // Interfaces do not need interface methods in their vtables 230 // This includes miranda methods and during later processing, default methods 231 if (!ik()->is_interface()) { 232 initialized = fill_in_mirandas(initialized); 233 } 234 235 // In class hierarchies where the accessibility is not increasing (i.e., going from private -> 236 // package_private -> public/protected), the vtable might actually be smaller than our initial 237 // calculation. 238 assert(initialized <= _length, "vtable initialization failed"); 239 for(;initialized < _length; initialized++) { 240 put_method_at(NULL, initialized); 241 } 242 NOT_PRODUCT(verify(tty, true)); 243 } 244 } 245 246 // Called for cases where a method does not override its superclass' vtable entry 247 // For bytecodes not produced by javac together it is possible that a method does not override 248 // the superclass's method, but might indirectly override a super-super class's vtable entry 249 // If none found, return a null superk, else return the superk of the method this does override 250 // For public and protected methods: if they override a superclass, they will 251 // also be overridden themselves appropriately. 252 // Private methods do not override and are not overridden. 253 // Package Private methods are trickier: 254 // e.g. P1.A, pub m 255 // P2.B extends A, package private m 256 // P1.C extends B, public m 257 // P1.C.m needs to override P1.A.m and can not override P2.B.m 258 // Therefore: all package private methods need their own vtable entries for 259 // them to be the root of an inheritance overriding decision 260 // Package private methods may also override other vtable entries 261 InstanceKlass* klassVtable::find_transitive_override(InstanceKlass* initialsuper, methodHandle target_method, 262 int vtable_index, Handle target_loader, Symbol* target_classname, Thread * THREAD) { 263 InstanceKlass* superk = initialsuper; 264 while (superk != NULL && superk->super() != NULL) { 265 InstanceKlass* supersuperklass = InstanceKlass::cast(superk->super()); 266 klassVtable* ssVtable = supersuperklass->vtable(); 267 if (vtable_index < ssVtable->length()) { 268 Method* super_method = ssVtable->method_at(vtable_index); 269 #ifndef PRODUCT 270 Symbol* name= target_method()->name(); 271 Symbol* signature = target_method()->signature(); 272 assert(super_method->name() == name && super_method->signature() == signature, "vtable entry name/sig mismatch"); 273 #endif 274 if (supersuperklass->is_override(super_method, target_loader, target_classname, THREAD)) { 275 if (develop_log_is_enabled(Trace, vtables)) { 276 ResourceMark rm(THREAD); 277 outputStream* logst = LogHandle(vtables)::trace_stream(); 278 char* sig = target_method()->name_and_sig_as_C_string(); 279 logst->print("transitive overriding superclass %s with %s::%s index %d, original flags: ", 280 supersuperklass->internal_name(), 281 _klass->internal_name(), sig, vtable_index); 282 super_method->print_linkage_flags(logst); 283 logst->print("overriders flags: "); 284 target_method->print_linkage_flags(logst); 285 logst->cr(); 286 } 287 288 break; // return found superk 289 } 290 } else { 291 // super class has no vtable entry here, stop transitive search 292 superk = (InstanceKlass*)NULL; 293 break; 294 } 295 // if no override found yet, continue to search up 296 superk = superk->super() == NULL ? NULL : InstanceKlass::cast(superk->super()); 297 } 298 299 return superk; 300 } 301 302 static void log_vtables(int i, bool overrides, methodHandle target_method, 303 KlassHandle target_klass, Method* super_method, 304 Thread* thread) { 305 #ifndef PRODUCT 306 if (develop_log_is_enabled(Trace, vtables)) { 307 ResourceMark rm(thread); 308 outputStream* logst = LogHandle(vtables)::trace_stream(); 309 char* sig = target_method()->name_and_sig_as_C_string(); 310 if (overrides) { 311 logst->print("overriding with %s::%s index %d, original flags: ", 312 target_klass->internal_name(), sig, i); 313 } else { 314 logst->print("NOT overriding with %s::%s index %d, original flags: ", 315 target_klass->internal_name(), sig, i); 316 } 317 super_method->print_linkage_flags(logst); 318 logst->print("overriders flags: "); 319 target_method->print_linkage_flags(logst); 320 logst->cr(); 321 } 322 #endif 323 } 324 325 // Update child's copy of super vtable for overrides 326 // OR return true if a new vtable entry is required. 327 // Only called for InstanceKlass's, i.e. not for arrays 328 // If that changed, could not use _klass as handle for klass 329 bool klassVtable::update_inherited_vtable(InstanceKlass* klass, methodHandle target_method, 330 int super_vtable_len, int default_index, 331 bool checkconstraints, TRAPS) { 332 ResourceMark rm; 333 bool allocate_new = true; 334 assert(klass->is_instance_klass(), "must be InstanceKlass"); 335 336 Array<int>* def_vtable_indices = NULL; 337 bool is_default = false; 338 // default methods are concrete methods in superinterfaces which are added to the vtable 339 // with their real method_holder 340 // Since vtable and itable indices share the same storage, don't touch 341 // the default method's real vtable/itable index 342 // default_vtable_indices stores the vtable value relative to this inheritor 343 if (default_index >= 0 ) { 344 is_default = true; 345 def_vtable_indices = klass->default_vtable_indices(); 346 assert(def_vtable_indices != NULL, "def vtable alloc?"); 347 assert(default_index <= def_vtable_indices->length(), "def vtable len?"); 348 } else { 349 assert(klass == target_method()->method_holder(), "caller resp."); 350 // Initialize the method's vtable index to "nonvirtual". 351 // If we allocate a vtable entry, we will update it to a non-negative number. 352 target_method()->set_vtable_index(Method::nonvirtual_vtable_index); 353 } 354 355 // Static and <init> methods are never in 356 if (target_method()->is_static() || target_method()->name() == vmSymbols::object_initializer_name()) { 357 return false; 358 } 359 360 if (target_method->is_final_method(klass->access_flags())) { 361 // a final method never needs a new entry; final methods can be statically 362 // resolved and they have to be present in the vtable only if they override 363 // a super's method, in which case they re-use its entry 364 allocate_new = false; 365 } else if (klass->is_interface()) { 366 allocate_new = false; // see note below in needs_new_vtable_entry 367 // An interface never allocates new vtable slots, only inherits old ones. 368 // This method will either be assigned its own itable index later, 369 // or be assigned an inherited vtable index in the loop below. 370 // default methods inherited by classes store their vtable indices 371 // in the inheritor's default_vtable_indices 372 // default methods inherited by interfaces may already have a 373 // valid itable index, if so, don't change it 374 // overpass methods in an interface will be assigned an itable index later 375 // by an inheriting class 376 if (!is_default || !target_method()->has_itable_index()) { 377 target_method()->set_vtable_index(Method::pending_itable_index); 378 } 379 } 380 381 // we need a new entry if there is no superclass 382 if (klass->super() == NULL) { 383 return allocate_new; 384 } 385 386 // private methods in classes always have a new entry in the vtable 387 // specification interpretation since classic has 388 // private methods not overriding 389 // JDK8 adds private methods in interfaces which require invokespecial 390 if (target_method()->is_private()) { 391 return allocate_new; 392 } 393 394 // search through the vtable and update overridden entries 395 // Since check_signature_loaders acquires SystemDictionary_lock 396 // which can block for gc, once we are in this loop, use handles 397 // For classfiles built with >= jdk7, we now look for transitive overrides 398 399 Symbol* name = target_method()->name(); 400 Symbol* signature = target_method()->signature(); 401 402 KlassHandle target_klass(THREAD, target_method()->method_holder()); 403 if (target_klass == NULL) { 404 target_klass = _klass; 405 } 406 407 Handle target_loader(THREAD, target_klass->class_loader()); 408 409 Symbol* target_classname = target_klass->name(); 410 for(int i = 0; i < super_vtable_len; i++) { 411 Method* super_method = method_at(i); 412 // Check if method name matches 413 if (super_method->name() == name && super_method->signature() == signature) { 414 415 // get super_klass for method_holder for the found method 416 InstanceKlass* super_klass = super_method->method_holder(); 417 418 // Whether the method is being overridden 419 bool overrides = false; 420 421 // private methods are also never overridden 422 if (!super_method->is_private() && 423 (is_default 424 || ((super_klass->is_override(super_method, target_loader, target_classname, THREAD)) 425 || ((klass->major_version() >= VTABLE_TRANSITIVE_OVERRIDE_VERSION) 426 && ((super_klass = find_transitive_override(super_klass, 427 target_method, i, target_loader, 428 target_classname, THREAD)) 429 != (InstanceKlass*)NULL))))) 430 { 431 // Package private methods always need a new entry to root their own 432 // overriding. They may also override other methods. 433 if (!target_method()->is_package_private()) { 434 allocate_new = false; 435 } 436 437 if (checkconstraints) { 438 // Override vtable entry if passes loader constraint check 439 // if loader constraint checking requested 440 // No need to visit his super, since he and his super 441 // have already made any needed loader constraints. 442 // Since loader constraints are transitive, it is enough 443 // to link to the first super, and we get all the others. 444 Handle super_loader(THREAD, super_klass->class_loader()); 445 446 if (target_loader() != super_loader()) { 447 ResourceMark rm(THREAD); 448 Symbol* failed_type_symbol = 449 SystemDictionary::check_signature_loaders(signature, target_loader, 450 super_loader, true, 451 CHECK_(false)); 452 if (failed_type_symbol != NULL) { 453 const char* msg = "loader constraint violation: when resolving " 454 "overridden method \"%s\" the class loader (instance" 455 " of %s) of the current class, %s, and its superclass loader " 456 "(instance of %s), have different Class objects for the type " 457 "%s used in the signature"; 458 char* sig = target_method()->name_and_sig_as_C_string(); 459 const char* loader1 = SystemDictionary::loader_name(target_loader()); 460 char* current = target_klass->name()->as_C_string(); 461 const char* loader2 = SystemDictionary::loader_name(super_loader()); 462 char* failed_type_name = failed_type_symbol->as_C_string(); 463 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) + 464 strlen(current) + strlen(loader2) + strlen(failed_type_name); 465 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen); 466 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2, 467 failed_type_name); 468 THROW_MSG_(vmSymbols::java_lang_LinkageError(), buf, false); 469 } 470 } 471 } 472 473 put_method_at(target_method(), i); 474 overrides = true; 475 if (!is_default) { 476 target_method()->set_vtable_index(i); 477 } else { 478 if (def_vtable_indices != NULL) { 479 def_vtable_indices->at_put(default_index, i); 480 } 481 assert(super_method->is_default_method() || super_method->is_overpass() 482 || super_method->is_abstract(), "default override error"); 483 } 484 } else { 485 overrides = false; 486 } 487 log_vtables(i, overrides, target_method, target_klass, super_method, THREAD); 488 } 489 } 490 return allocate_new; 491 } 492 493 void klassVtable::put_method_at(Method* m, int index) { 494 if (develop_log_is_enabled(Trace, vtables)) { 495 ResourceMark rm; 496 outputStream* logst = LogHandle(vtables)::trace_stream(); 497 const char* sig = (m != NULL) ? m->name_and_sig_as_C_string() : "<NULL>"; 498 logst->print("adding %s at index %d, flags: ", sig, index); 499 if (m != NULL) { 500 m->print_linkage_flags(logst); 501 } 502 logst->cr(); 503 } 504 table()[index].set(m); 505 } 506 507 // Find out if a method "m" with superclass "super", loader "classloader" and 508 // name "classname" needs a new vtable entry. Let P be a class package defined 509 // by "classloader" and "classname". 510 // NOTE: The logic used here is very similar to the one used for computing 511 // the vtables indices for a method. We cannot directly use that function because, 512 // we allocate the InstanceKlass at load time, and that requires that the 513 // superclass has been loaded. 514 // However, the vtable entries are filled in at link time, and therefore 515 // the superclass' vtable may not yet have been filled in. 516 bool klassVtable::needs_new_vtable_entry(methodHandle target_method, 517 const Klass* super, 518 Handle classloader, 519 Symbol* classname, 520 AccessFlags class_flags, 521 TRAPS) { 522 if (class_flags.is_interface()) { 523 // Interfaces do not use vtables, except for java.lang.Object methods, 524 // so there is no point to assigning 525 // a vtable index to any of their local methods. If we refrain from doing this, 526 // we can use Method::_vtable_index to hold the itable index 527 return false; 528 } 529 530 if (target_method->is_final_method(class_flags) || 531 // a final method never needs a new entry; final methods can be statically 532 // resolved and they have to be present in the vtable only if they override 533 // a super's method, in which case they re-use its entry 534 (target_method()->is_static()) || 535 // static methods don't need to be in vtable 536 (target_method()->name() == vmSymbols::object_initializer_name()) 537 // <init> is never called dynamically-bound 538 ) { 539 return false; 540 } 541 542 // Concrete interface methods do not need new entries, they override 543 // abstract method entries using default inheritance rules 544 if (target_method()->method_holder() != NULL && 545 target_method()->method_holder()->is_interface() && 546 !target_method()->is_abstract() ) { 547 return false; 548 } 549 550 // we need a new entry if there is no superclass 551 if (super == NULL) { 552 return true; 553 } 554 555 // private methods in classes always have a new entry in the vtable 556 // specification interpretation since classic has 557 // private methods not overriding 558 // JDK8 adds private methods in interfaces which require invokespecial 559 if (target_method()->is_private()) { 560 return true; 561 } 562 563 // Package private methods always need a new entry to root their own 564 // overriding. This allows transitive overriding to work. 565 if (target_method()->is_package_private()) { 566 return true; 567 } 568 569 // search through the super class hierarchy to see if we need 570 // a new entry 571 ResourceMark rm; 572 Symbol* name = target_method()->name(); 573 Symbol* signature = target_method()->signature(); 574 const Klass* k = super; 575 Method* super_method = NULL; 576 InstanceKlass *holder = NULL; 577 Method* recheck_method = NULL; 578 while (k != NULL) { 579 // lookup through the hierarchy for a method with matching name and sign. 580 super_method = InstanceKlass::cast(k)->lookup_method(name, signature); 581 if (super_method == NULL) { 582 break; // we still have to search for a matching miranda method 583 } 584 // get the class holding the matching method 585 // make sure you use that class for is_override 586 InstanceKlass* superk = super_method->method_holder(); 587 // we want only instance method matches 588 // pretend private methods are not in the super vtable 589 // since we do override around them: e.g. a.m pub/b.m private/c.m pub, 590 // ignore private, c.m pub does override a.m pub 591 // For classes that were not javac'd together, we also do transitive overriding around 592 // methods that have less accessibility 593 if ((!super_method->is_static()) && 594 (!super_method->is_private())) { 595 if (superk->is_override(super_method, classloader, classname, THREAD)) { 596 return false; 597 // else keep looking for transitive overrides 598 } 599 } 600 601 // Start with lookup result and continue to search up 602 k = superk->super(); // haven't found an override match yet; continue to look 603 } 604 605 // if the target method is public or protected it may have a matching 606 // miranda method in the super, whose entry it should re-use. 607 // Actually, to handle cases that javac would not generate, we need 608 // this check for all access permissions. 609 const InstanceKlass *sk = InstanceKlass::cast(super); 610 if (sk->has_miranda_methods()) { 611 if (sk->lookup_method_in_all_interfaces(name, signature, Klass::find_defaults) != NULL) { 612 return false; // found a matching miranda; we do not need a new entry 613 } 614 } 615 return true; // found no match; we need a new entry 616 } 617 618 // Support for miranda methods 619 620 // get the vtable index of a miranda method with matching "name" and "signature" 621 int klassVtable::index_of_miranda(Symbol* name, Symbol* signature) { 622 // search from the bottom, might be faster 623 for (int i = (length() - 1); i >= 0; i--) { 624 Method* m = table()[i].method(); 625 if (is_miranda_entry_at(i) && 626 m->name() == name && m->signature() == signature) { 627 return i; 628 } 629 } 630 return Method::invalid_vtable_index; 631 } 632 633 // check if an entry at an index is miranda 634 // requires that method m at entry be declared ("held") by an interface. 635 bool klassVtable::is_miranda_entry_at(int i) { 636 Method* m = method_at(i); 637 Klass* method_holder = m->method_holder(); 638 InstanceKlass *mhk = InstanceKlass::cast(method_holder); 639 640 // miranda methods are public abstract instance interface methods in a class's vtable 641 if (mhk->is_interface()) { 642 assert(m->is_public(), "should be public"); 643 assert(ik()->implements_interface(method_holder) , "this class should implement the interface"); 644 if (is_miranda(m, ik()->methods(), ik()->default_methods(), ik()->super())) { 645 return true; 646 } 647 } 648 return false; 649 } 650 651 // Check if a method is a miranda method, given a class's methods array, 652 // its default_method table and its super class. 653 // "Miranda" means an abstract non-private method that would not be 654 // overridden for the local class. 655 // A "miranda" method should only include non-private interface 656 // instance methods, i.e. not private methods, not static methods, 657 // not default methods (concrete interface methods), not overpass methods. 658 // If a given class already has a local (including overpass) method, a 659 // default method, or any of its superclasses has the same which would have 660 // overridden an abstract method, then this is not a miranda method. 661 // 662 // Miranda methods are checked multiple times. 663 // Pass 1: during class load/class file parsing: before vtable size calculation: 664 // include superinterface abstract and default methods (non-private instance). 665 // We include potential default methods to give them space in the vtable. 666 // During the first run, the current instanceKlass has not yet been 667 // created, the superclasses and superinterfaces do have instanceKlasses 668 // but may not have vtables, the default_methods list is empty, no overpasses. 669 // This is seen by default method creation. 670 // 671 // Pass 2: recalculated during vtable initialization: only include abstract methods. 672 // The goal of pass 2 is to walk through the superinterfaces to see if any of 673 // the superinterface methods (which were all abstract pre-default methods) 674 // need to be added to the vtable. 675 // With the addition of default methods, we have three new challenges: 676 // overpasses, static interface methods and private interface methods. 677 // Static and private interface methods do not get added to the vtable and 678 // are not seen by the method resolution process, so we skip those. 679 // Overpass methods are already in the vtable, so vtable lookup will 680 // find them and we don't need to add a miranda method to the end of 681 // the vtable. So we look for overpass methods and if they are found we 682 // return false. Note that we inherit our superclasses vtable, so 683 // the superclass' search also needs to use find_overpass so that if 684 // one is found we return false. 685 // False means - we don't need a miranda method added to the vtable. 686 // 687 // During the second run, default_methods is set up, so concrete methods from 688 // superinterfaces with matching names/signatures to default_methods are already 689 // in the default_methods list and do not need to be appended to the vtable 690 // as mirandas. Abstract methods may already have been handled via 691 // overpasses - either local or superclass overpasses, which may be 692 // in the vtable already. 693 // 694 // Pass 3: They are also checked by link resolution and selection, 695 // for invocation on a method (not interface method) reference that 696 // resolves to a method with an interface as its method_holder. 697 // Used as part of walking from the bottom of the vtable to find 698 // the vtable index for the miranda method. 699 // 700 // Part of the Miranda Rights in the US mean that if you do not have 701 // an attorney one will be appointed for you. 702 bool klassVtable::is_miranda(Method* m, Array<Method*>* class_methods, 703 Array<Method*>* default_methods, const Klass* super) { 704 if (m->is_static() || m->is_private() || m->is_overpass()) { 705 return false; 706 } 707 Symbol* name = m->name(); 708 Symbol* signature = m->signature(); 709 710 // First look in local methods to see if already covered 711 if (InstanceKlass::find_local_method(class_methods, name, signature, 712 Klass::find_overpass, Klass::skip_static, Klass::skip_private) != NULL) 713 { 714 return false; 715 } 716 717 // Check local default methods 718 if ((default_methods != NULL) && 719 (InstanceKlass::find_method(default_methods, name, signature) != NULL)) 720 { 721 return false; 722 } 723 724 // Iterate on all superclasses, which should be InstanceKlasses. 725 // Note that we explicitly look for overpasses at each level. 726 // Overpasses may or may not exist for supers for pass 1, 727 // they should have been created for pass 2 and later. 728 729 for (const Klass* cursuper = super; cursuper != NULL; cursuper = cursuper->super()) 730 { 731 if (InstanceKlass::cast(cursuper)->find_local_method(name, signature, 732 Klass::find_overpass, Klass::skip_static, Klass::skip_private) != NULL) { 733 return false; 734 } 735 } 736 737 return true; 738 } 739 740 // Scans current_interface_methods for miranda methods that do not 741 // already appear in new_mirandas, or default methods, and are also not defined-and-non-private 742 // in super (superclass). These mirandas are added to all_mirandas if it is 743 // not null; in addition, those that are not duplicates of miranda methods 744 // inherited by super from its interfaces are added to new_mirandas. 745 // Thus, new_mirandas will be the set of mirandas that this class introduces, 746 // all_mirandas will be the set of all mirandas applicable to this class 747 // including all defined in superclasses. 748 void klassVtable::add_new_mirandas_to_lists( 749 GrowableArray<Method*>* new_mirandas, GrowableArray<Method*>* all_mirandas, 750 Array<Method*>* current_interface_methods, Array<Method*>* class_methods, 751 Array<Method*>* default_methods, const Klass* super) { 752 753 // iterate thru the current interface's method to see if it a miranda 754 int num_methods = current_interface_methods->length(); 755 for (int i = 0; i < num_methods; i++) { 756 Method* im = current_interface_methods->at(i); 757 bool is_duplicate = false; 758 int num_of_current_mirandas = new_mirandas->length(); 759 // check for duplicate mirandas in different interfaces we implement 760 for (int j = 0; j < num_of_current_mirandas; j++) { 761 Method* miranda = new_mirandas->at(j); 762 if ((im->name() == miranda->name()) && 763 (im->signature() == miranda->signature())) { 764 is_duplicate = true; 765 break; 766 } 767 } 768 769 if (!is_duplicate) { // we don't want duplicate miranda entries in the vtable 770 if (is_miranda(im, class_methods, default_methods, super)) { // is it a miranda at all? 771 const InstanceKlass *sk = InstanceKlass::cast(super); 772 // check if it is a duplicate of a super's miranda 773 if (sk->lookup_method_in_all_interfaces(im->name(), im->signature(), Klass::find_defaults) == NULL) { 774 new_mirandas->append(im); 775 } 776 if (all_mirandas != NULL) { 777 all_mirandas->append(im); 778 } 779 } 780 } 781 } 782 } 783 784 void klassVtable::get_mirandas(GrowableArray<Method*>* new_mirandas, 785 GrowableArray<Method*>* all_mirandas, 786 const Klass* super, 787 Array<Method*>* class_methods, 788 Array<Method*>* default_methods, 789 Array<Klass*>* local_interfaces) { 790 assert((new_mirandas->length() == 0) , "current mirandas must be 0"); 791 792 // iterate thru the local interfaces looking for a miranda 793 int num_local_ifs = local_interfaces->length(); 794 for (int i = 0; i < num_local_ifs; i++) { 795 InstanceKlass *ik = InstanceKlass::cast(local_interfaces->at(i)); 796 add_new_mirandas_to_lists(new_mirandas, all_mirandas, 797 ik->methods(), class_methods, 798 default_methods, super); 799 // iterate thru each local's super interfaces 800 Array<Klass*>* super_ifs = ik->transitive_interfaces(); 801 int num_super_ifs = super_ifs->length(); 802 for (int j = 0; j < num_super_ifs; j++) { 803 InstanceKlass *sik = InstanceKlass::cast(super_ifs->at(j)); 804 add_new_mirandas_to_lists(new_mirandas, all_mirandas, 805 sik->methods(), class_methods, 806 default_methods, super); 807 } 808 } 809 } 810 811 // Discover miranda methods ("miranda" = "interface abstract, no binding"), 812 // and append them into the vtable starting at index initialized, 813 // return the new value of initialized. 814 // Miranda methods use vtable entries, but do not get assigned a vtable_index 815 // The vtable_index is discovered by searching from the end of the vtable 816 int klassVtable::fill_in_mirandas(int initialized) { 817 GrowableArray<Method*> mirandas(20); 818 get_mirandas(&mirandas, NULL, ik()->super(), ik()->methods(), 819 ik()->default_methods(), ik()->local_interfaces()); 820 for (int i = 0; i < mirandas.length(); i++) { 821 if (develop_log_is_enabled(Trace, vtables)) { 822 Method* meth = mirandas.at(i); 823 ResourceMark rm(Thread::current()); 824 outputStream* logst = LogHandle(vtables)::trace_stream(); 825 if (meth != NULL) { 826 char* sig = meth->name_and_sig_as_C_string(); 827 logst->print("fill in mirandas with %s index %d, flags: ", 828 sig, initialized); 829 meth->print_linkage_flags(logst); 830 logst->cr(); 831 } 832 } 833 put_method_at(mirandas.at(i), initialized); 834 ++initialized; 835 } 836 return initialized; 837 } 838 839 // Copy this class's vtable to the vtable beginning at start. 840 // Used to copy superclass vtable to prefix of subclass's vtable. 841 void klassVtable::copy_vtable_to(vtableEntry* start) { 842 Copy::disjoint_words((HeapWord*)table(), (HeapWord*)start, _length * vtableEntry::size()); 843 } 844 845 #if INCLUDE_JVMTI 846 bool klassVtable::adjust_default_method(int vtable_index, Method* old_method, Method* new_method) { 847 // If old_method is default, find this vtable index in default_vtable_indices 848 // and replace that method in the _default_methods list 849 bool updated = false; 850 851 Array<Method*>* default_methods = ik()->default_methods(); 852 if (default_methods != NULL) { 853 int len = default_methods->length(); 854 for (int idx = 0; idx < len; idx++) { 855 if (vtable_index == ik()->default_vtable_indices()->at(idx)) { 856 if (default_methods->at(idx) == old_method) { 857 default_methods->at_put(idx, new_method); 858 updated = true; 859 } 860 break; 861 } 862 } 863 } 864 return updated; 865 } 866 867 // search the vtable for uses of either obsolete or EMCP methods 868 void klassVtable::adjust_method_entries(InstanceKlass* holder, bool * trace_name_printed) { 869 int prn_enabled = 0; 870 for (int index = 0; index < length(); index++) { 871 Method* old_method = unchecked_method_at(index); 872 if (old_method == NULL || old_method->method_holder() != holder || !old_method->is_old()) { 873 continue; // skip uninteresting entries 874 } 875 assert(!old_method->is_deleted(), "vtable methods may not be deleted"); 876 877 Method* new_method = holder->method_with_idnum(old_method->orig_method_idnum()); 878 879 assert(new_method != NULL, "method_with_idnum() should not be NULL"); 880 assert(old_method != new_method, "sanity check"); 881 882 put_method_at(new_method, index); 883 // For default methods, need to update the _default_methods array 884 // which can only have one method entry for a given signature 885 bool updated_default = false; 886 if (old_method->is_default_method()) { 887 updated_default = adjust_default_method(index, old_method, new_method); 888 } 889 890 if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) { 891 if (!(*trace_name_printed)) { 892 // RC_TRACE_MESG macro has an embedded ResourceMark 893 RC_TRACE_MESG(("adjust: klassname=%s for methods from name=%s", 894 klass()->external_name(), 895 old_method->method_holder()->external_name())); 896 *trace_name_printed = true; 897 } 898 // RC_TRACE macro has an embedded ResourceMark 899 RC_TRACE(0x00100000, ("vtable method update: %s(%s), updated default = %s", 900 new_method->name()->as_C_string(), 901 new_method->signature()->as_C_string(), 902 updated_default ? "true" : "false")); 903 } 904 } 905 } 906 907 // a vtable should never contain old or obsolete methods 908 bool klassVtable::check_no_old_or_obsolete_entries() { 909 for (int i = 0; i < length(); i++) { 910 Method* m = unchecked_method_at(i); 911 if (m != NULL && 912 (NOT_PRODUCT(!m->is_valid() ||) m->is_old() || m->is_obsolete())) { 913 return false; 914 } 915 } 916 return true; 917 } 918 919 void klassVtable::dump_vtable() { 920 tty->print_cr("vtable dump --"); 921 for (int i = 0; i < length(); i++) { 922 Method* m = unchecked_method_at(i); 923 if (m != NULL) { 924 tty->print(" (%5d) ", i); 925 m->access_flags().print_on(tty); 926 if (m->is_default_method()) { 927 tty->print("default "); 928 } 929 if (m->is_overpass()) { 930 tty->print("overpass"); 931 } 932 tty->print(" -- "); 933 m->print_name(tty); 934 tty->cr(); 935 } 936 } 937 } 938 #endif // INCLUDE_JVMTI 939 940 // CDS/RedefineClasses support - clear vtables so they can be reinitialized 941 void klassVtable::clear_vtable() { 942 for (int i = 0; i < _length; i++) table()[i].clear(); 943 } 944 945 bool klassVtable::is_initialized() { 946 return _length == 0 || table()[0].method() != NULL; 947 } 948 949 //----------------------------------------------------------------------------------------- 950 // Itable code 951 952 // Initialize a itableMethodEntry 953 void itableMethodEntry::initialize(Method* m) { 954 if (m == NULL) return; 955 956 _method = m; 957 } 958 959 klassItable::klassItable(instanceKlassHandle klass) { 960 _klass = klass; 961 962 if (klass->itable_length() > 0) { 963 itableOffsetEntry* offset_entry = (itableOffsetEntry*)klass->start_of_itable(); 964 if (offset_entry != NULL && offset_entry->interface_klass() != NULL) { // Check that itable is initialized 965 // First offset entry points to the first method_entry 966 intptr_t* method_entry = (intptr_t *)(((address)klass()) + offset_entry->offset()); 967 intptr_t* end = klass->end_of_itable(); 968 969 _table_offset = (intptr_t*)offset_entry - (intptr_t*)klass(); 970 _size_offset_table = (method_entry - ((intptr_t*)offset_entry)) / itableOffsetEntry::size(); 971 _size_method_table = (end - method_entry) / itableMethodEntry::size(); 972 assert(_table_offset >= 0 && _size_offset_table >= 0 && _size_method_table >= 0, "wrong computation"); 973 return; 974 } 975 } 976 977 // The length of the itable was either zero, or it has not yet been initialized. 978 _table_offset = 0; 979 _size_offset_table = 0; 980 _size_method_table = 0; 981 } 982 983 static int initialize_count = 0; 984 985 // Initialization 986 void klassItable::initialize_itable(bool checkconstraints, TRAPS) { 987 if (_klass->is_interface()) { 988 // This needs to go after vtable indices are assigned but 989 // before implementors need to know the number of itable indices. 990 assign_itable_indices_for_interface(_klass()); 991 } 992 993 // Cannot be setup doing bootstrapping, interfaces don't have 994 // itables, and klass with only ones entry have empty itables 995 if (Universe::is_bootstrapping() || 996 _klass->is_interface() || 997 _klass->itable_length() == itableOffsetEntry::size()) return; 998 999 // There's alway an extra itable entry so we can null-terminate it. 1000 guarantee(size_offset_table() >= 1, "too small"); 1001 int num_interfaces = size_offset_table() - 1; 1002 if (num_interfaces > 0) { 1003 log_develop_debug(itables)("%3d: Initializing itables for %s", ++initialize_count, 1004 _klass->name()->as_C_string()); 1005 1006 1007 // Iterate through all interfaces 1008 int i; 1009 for(i = 0; i < num_interfaces; i++) { 1010 itableOffsetEntry* ioe = offset_entry(i); 1011 HandleMark hm(THREAD); 1012 KlassHandle interf_h (THREAD, ioe->interface_klass()); 1013 assert(interf_h() != NULL && ioe->offset() != 0, "bad offset entry in itable"); 1014 initialize_itable_for_interface(ioe->offset(), interf_h, checkconstraints, CHECK); 1015 } 1016 1017 } 1018 // Check that the last entry is empty 1019 itableOffsetEntry* ioe = offset_entry(size_offset_table() - 1); 1020 guarantee(ioe->interface_klass() == NULL && ioe->offset() == 0, "terminator entry missing"); 1021 } 1022 1023 1024 inline bool interface_method_needs_itable_index(Method* m) { 1025 if (m->is_static()) return false; // e.g., Stream.empty 1026 if (m->is_initializer()) return false; // <init> or <clinit> 1027 // If an interface redeclares a method from java.lang.Object, 1028 // it should already have a vtable index, don't touch it. 1029 // e.g., CharSequence.toString (from initialize_vtable) 1030 // if (m->has_vtable_index()) return false; // NO! 1031 return true; 1032 } 1033 1034 int klassItable::assign_itable_indices_for_interface(Klass* klass) { 1035 // an interface does not have an itable, but its methods need to be numbered 1036 log_develop_debug(itables)("%3d: Initializing itable indices for interface %s", 1037 ++initialize_count, klass->name()->as_C_string()); 1038 Array<Method*>* methods = InstanceKlass::cast(klass)->methods(); 1039 int nof_methods = methods->length(); 1040 int ime_num = 0; 1041 for (int i = 0; i < nof_methods; i++) { 1042 Method* m = methods->at(i); 1043 if (interface_method_needs_itable_index(m)) { 1044 assert(!m->is_final_method(), "no final interface methods"); 1045 // If m is already assigned a vtable index, do not disturb it. 1046 if (develop_log_is_enabled(Trace, itables)) { 1047 ResourceMark rm; 1048 outputStream* logst = LogHandle(itables)::trace_stream(); 1049 assert(m != NULL, "methods can never be null"); 1050 const char* sig = m->name_and_sig_as_C_string(); 1051 if (m->has_vtable_index()) { 1052 logst->print("vtable index %d for method: %s, flags: ", m->vtable_index(), sig); 1053 } else { 1054 logst->print("itable index %d for method: %s, flags: ", ime_num, sig); 1055 } 1056 m->print_linkage_flags(logst); 1057 logst->cr(); 1058 } 1059 if (!m->has_vtable_index()) { 1060 assert(m->vtable_index() == Method::pending_itable_index, "set by initialize_vtable"); 1061 m->set_itable_index(ime_num); 1062 // Progress to next itable entry 1063 ime_num++; 1064 } 1065 } 1066 } 1067 assert(ime_num == method_count_for_interface(klass), "proper sizing"); 1068 return ime_num; 1069 } 1070 1071 int klassItable::method_count_for_interface(Klass* interf) { 1072 assert(interf->is_instance_klass(), "must be"); 1073 assert(interf->is_interface(), "must be"); 1074 Array<Method*>* methods = InstanceKlass::cast(interf)->methods(); 1075 int nof_methods = methods->length(); 1076 int length = 0; 1077 while (nof_methods > 0) { 1078 Method* m = methods->at(nof_methods-1); 1079 if (m->has_itable_index()) { 1080 length = m->itable_index() + 1; 1081 break; 1082 } 1083 nof_methods -= 1; 1084 } 1085 #ifdef ASSERT 1086 int nof_methods_copy = nof_methods; 1087 while (nof_methods_copy > 0) { 1088 Method* mm = methods->at(--nof_methods_copy); 1089 assert(!mm->has_itable_index() || mm->itable_index() < length, ""); 1090 } 1091 #endif //ASSERT 1092 // return the rightmost itable index, plus one; or 0 if no methods have 1093 // itable indices 1094 return length; 1095 } 1096 1097 1098 void klassItable::initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS) { 1099 Array<Method*>* methods = InstanceKlass::cast(interf_h())->methods(); 1100 int nof_methods = methods->length(); 1101 HandleMark hm; 1102 assert(nof_methods > 0, "at least one method must exist for interface to be in vtable"); 1103 Handle interface_loader (THREAD, InstanceKlass::cast(interf_h())->class_loader()); 1104 1105 int ime_count = method_count_for_interface(interf_h()); 1106 for (int i = 0; i < nof_methods; i++) { 1107 Method* m = methods->at(i); 1108 methodHandle target; 1109 if (m->has_itable_index()) { 1110 // This search must match the runtime resolution, i.e. selection search for invokeinterface 1111 // to correctly enforce loader constraints for interface method inheritance 1112 target = LinkResolver::lookup_instance_method_in_klasses(_klass, m->name(), m->signature(), CHECK); 1113 } 1114 if (target == NULL || !target->is_public() || target->is_abstract()) { 1115 // Entry does not resolve. Leave it empty for AbstractMethodError. 1116 if (!(target == NULL) && !target->is_public()) { 1117 // Stuff an IllegalAccessError throwing method in there instead. 1118 itableOffsetEntry::method_entry(_klass(), method_table_offset)[m->itable_index()]. 1119 initialize(Universe::throw_illegal_access_error()); 1120 } 1121 } else { 1122 // Entry did resolve, check loader constraints before initializing 1123 // if checkconstraints requested 1124 if (checkconstraints) { 1125 Handle method_holder_loader (THREAD, target->method_holder()->class_loader()); 1126 if (method_holder_loader() != interface_loader()) { 1127 ResourceMark rm(THREAD); 1128 Symbol* failed_type_symbol = 1129 SystemDictionary::check_signature_loaders(m->signature(), 1130 method_holder_loader, 1131 interface_loader, 1132 true, CHECK); 1133 if (failed_type_symbol != NULL) { 1134 const char* msg = "loader constraint violation in interface " 1135 "itable initialization: when resolving method \"%s\" the class" 1136 " loader (instance of %s) of the current class, %s, " 1137 "and the class loader (instance of %s) for interface " 1138 "%s have different Class objects for the type %s " 1139 "used in the signature"; 1140 char* sig = target()->name_and_sig_as_C_string(); 1141 const char* loader1 = SystemDictionary::loader_name(method_holder_loader()); 1142 char* current = _klass->name()->as_C_string(); 1143 const char* loader2 = SystemDictionary::loader_name(interface_loader()); 1144 char* iface = InstanceKlass::cast(interf_h())->name()->as_C_string(); 1145 char* failed_type_name = failed_type_symbol->as_C_string(); 1146 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) + 1147 strlen(current) + strlen(loader2) + strlen(iface) + 1148 strlen(failed_type_name); 1149 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen); 1150 jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2, 1151 iface, failed_type_name); 1152 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf); 1153 } 1154 } 1155 } 1156 1157 // ime may have moved during GC so recalculate address 1158 int ime_num = m->itable_index(); 1159 assert(ime_num < ime_count, "oob"); 1160 itableOffsetEntry::method_entry(_klass(), method_table_offset)[ime_num].initialize(target()); 1161 if (develop_log_is_enabled(Trace, itables)) { 1162 ResourceMark rm(THREAD); 1163 if (target() != NULL) { 1164 outputStream* logst = LogHandle(itables)::trace_stream(); 1165 char* sig = target()->name_and_sig_as_C_string(); 1166 logst->print("interface: %s, ime_num: %d, target: %s, method_holder: %s ", 1167 interf_h()->internal_name(), ime_num, sig, 1168 target()->method_holder()->internal_name()); 1169 logst->print("target_method flags: "); 1170 target()->print_linkage_flags(logst); 1171 logst->cr(); 1172 } 1173 } 1174 } 1175 } 1176 } 1177 1178 // Update entry for specific Method* 1179 void klassItable::initialize_with_method(Method* m) { 1180 itableMethodEntry* ime = method_entry(0); 1181 for(int i = 0; i < _size_method_table; i++) { 1182 if (ime->method() == m) { 1183 ime->initialize(m); 1184 } 1185 ime++; 1186 } 1187 } 1188 1189 #if INCLUDE_JVMTI 1190 // search the itable for uses of either obsolete or EMCP methods 1191 void klassItable::adjust_method_entries(InstanceKlass* holder, bool * trace_name_printed) { 1192 1193 itableMethodEntry* ime = method_entry(0); 1194 for (int i = 0; i < _size_method_table; i++, ime++) { 1195 Method* old_method = ime->method(); 1196 if (old_method == NULL || old_method->method_holder() != holder || !old_method->is_old()) { 1197 continue; // skip uninteresting entries 1198 } 1199 assert(!old_method->is_deleted(), "itable methods may not be deleted"); 1200 1201 Method* new_method = holder->method_with_idnum(old_method->orig_method_idnum()); 1202 1203 assert(new_method != NULL, "method_with_idnum() should not be NULL"); 1204 assert(old_method != new_method, "sanity check"); 1205 1206 ime->initialize(new_method); 1207 1208 if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) { 1209 if (!(*trace_name_printed)) { 1210 // RC_TRACE_MESG macro has an embedded ResourceMark 1211 RC_TRACE_MESG(("adjust: name=%s", 1212 old_method->method_holder()->external_name())); 1213 *trace_name_printed = true; 1214 } 1215 // RC_TRACE macro has an embedded ResourceMark 1216 RC_TRACE(0x00200000, ("itable method update: %s(%s)", 1217 new_method->name()->as_C_string(), 1218 new_method->signature()->as_C_string())); 1219 } 1220 } 1221 } 1222 1223 // an itable should never contain old or obsolete methods 1224 bool klassItable::check_no_old_or_obsolete_entries() { 1225 itableMethodEntry* ime = method_entry(0); 1226 for (int i = 0; i < _size_method_table; i++) { 1227 Method* m = ime->method(); 1228 if (m != NULL && 1229 (NOT_PRODUCT(!m->is_valid() ||) m->is_old() || m->is_obsolete())) { 1230 return false; 1231 } 1232 ime++; 1233 } 1234 return true; 1235 } 1236 1237 void klassItable::dump_itable() { 1238 itableMethodEntry* ime = method_entry(0); 1239 tty->print_cr("itable dump --"); 1240 for (int i = 0; i < _size_method_table; i++) { 1241 Method* m = ime->method(); 1242 if (m != NULL) { 1243 tty->print(" (%5d) ", i); 1244 m->access_flags().print_on(tty); 1245 if (m->is_default_method()) { 1246 tty->print("default "); 1247 } 1248 tty->print(" -- "); 1249 m->print_name(tty); 1250 tty->cr(); 1251 } 1252 ime++; 1253 } 1254 } 1255 #endif // INCLUDE_JVMTI 1256 1257 1258 // Setup 1259 class InterfaceVisiterClosure : public StackObj { 1260 public: 1261 virtual void doit(Klass* intf, int method_count) = 0; 1262 }; 1263 1264 // Visit all interfaces with at least one itable method 1265 void visit_all_interfaces(Array<Klass*>* transitive_intf, InterfaceVisiterClosure *blk) { 1266 // Handle array argument 1267 for(int i = 0; i < transitive_intf->length(); i++) { 1268 Klass* intf = transitive_intf->at(i); 1269 assert(intf->is_interface(), "sanity check"); 1270 1271 // Find no. of itable methods 1272 int method_count = 0; 1273 // method_count = klassItable::method_count_for_interface(intf); 1274 Array<Method*>* methods = InstanceKlass::cast(intf)->methods(); 1275 if (methods->length() > 0) { 1276 for (int i = methods->length(); --i >= 0; ) { 1277 if (interface_method_needs_itable_index(methods->at(i))) { 1278 method_count++; 1279 } 1280 } 1281 } 1282 1283 // Only count interfaces with at least one method 1284 if (method_count > 0) { 1285 blk->doit(intf, method_count); 1286 } 1287 } 1288 } 1289 1290 class CountInterfacesClosure : public InterfaceVisiterClosure { 1291 private: 1292 int _nof_methods; 1293 int _nof_interfaces; 1294 public: 1295 CountInterfacesClosure() { _nof_methods = 0; _nof_interfaces = 0; } 1296 1297 int nof_methods() const { return _nof_methods; } 1298 int nof_interfaces() const { return _nof_interfaces; } 1299 1300 void doit(Klass* intf, int method_count) { _nof_methods += method_count; _nof_interfaces++; } 1301 }; 1302 1303 class SetupItableClosure : public InterfaceVisiterClosure { 1304 private: 1305 itableOffsetEntry* _offset_entry; 1306 itableMethodEntry* _method_entry; 1307 address _klass_begin; 1308 public: 1309 SetupItableClosure(address klass_begin, itableOffsetEntry* offset_entry, itableMethodEntry* method_entry) { 1310 _klass_begin = klass_begin; 1311 _offset_entry = offset_entry; 1312 _method_entry = method_entry; 1313 } 1314 1315 itableMethodEntry* method_entry() const { return _method_entry; } 1316 1317 void doit(Klass* intf, int method_count) { 1318 int offset = ((address)_method_entry) - _klass_begin; 1319 _offset_entry->initialize(intf, offset); 1320 _offset_entry++; 1321 _method_entry += method_count; 1322 } 1323 }; 1324 1325 int klassItable::compute_itable_size(Array<Klass*>* transitive_interfaces) { 1326 // Count no of interfaces and total number of interface methods 1327 CountInterfacesClosure cic; 1328 visit_all_interfaces(transitive_interfaces, &cic); 1329 1330 // There's alway an extra itable entry so we can null-terminate it. 1331 int itable_size = calc_itable_size(cic.nof_interfaces() + 1, cic.nof_methods()); 1332 1333 // Statistics 1334 update_stats(itable_size * HeapWordSize); 1335 1336 return itable_size; 1337 } 1338 1339 1340 // Fill out offset table and interface klasses into the itable space 1341 void klassItable::setup_itable_offset_table(instanceKlassHandle klass) { 1342 if (klass->itable_length() == 0) return; 1343 assert(!klass->is_interface(), "Should have zero length itable"); 1344 1345 // Count no of interfaces and total number of interface methods 1346 CountInterfacesClosure cic; 1347 visit_all_interfaces(klass->transitive_interfaces(), &cic); 1348 int nof_methods = cic.nof_methods(); 1349 int nof_interfaces = cic.nof_interfaces(); 1350 1351 // Add one extra entry so we can null-terminate the table 1352 nof_interfaces++; 1353 1354 assert(compute_itable_size(klass->transitive_interfaces()) == 1355 calc_itable_size(nof_interfaces, nof_methods), 1356 "mismatch calculation of itable size"); 1357 1358 // Fill-out offset table 1359 itableOffsetEntry* ioe = (itableOffsetEntry*)klass->start_of_itable(); 1360 itableMethodEntry* ime = (itableMethodEntry*)(ioe + nof_interfaces); 1361 intptr_t* end = klass->end_of_itable(); 1362 assert((oop*)(ime + nof_methods) <= (oop*)klass->start_of_nonstatic_oop_maps(), "wrong offset calculation (1)"); 1363 assert((oop*)(end) == (oop*)(ime + nof_methods), "wrong offset calculation (2)"); 1364 1365 // Visit all interfaces and initialize itable offset table 1366 SetupItableClosure sic((address)klass(), ioe, ime); 1367 visit_all_interfaces(klass->transitive_interfaces(), &sic); 1368 1369 #ifdef ASSERT 1370 ime = sic.method_entry(); 1371 oop* v = (oop*) klass->end_of_itable(); 1372 assert( (oop*)(ime) == v, "wrong offset calculation (2)"); 1373 #endif 1374 } 1375 1376 1377 // inverse to itable_index 1378 Method* klassItable::method_for_itable_index(Klass* intf, int itable_index) { 1379 assert(InstanceKlass::cast(intf)->is_interface(), "sanity check"); 1380 assert(intf->verify_itable_index(itable_index), ""); 1381 Array<Method*>* methods = InstanceKlass::cast(intf)->methods(); 1382 1383 if (itable_index < 0 || itable_index >= method_count_for_interface(intf)) 1384 return NULL; // help caller defend against bad indices 1385 1386 int index = itable_index; 1387 Method* m = methods->at(index); 1388 int index2 = -1; 1389 while (!m->has_itable_index() || 1390 (index2 = m->itable_index()) != itable_index) { 1391 assert(index2 < itable_index, "monotonic"); 1392 if (++index == methods->length()) 1393 return NULL; 1394 m = methods->at(index); 1395 } 1396 assert(m->itable_index() == itable_index, "correct inverse"); 1397 1398 return m; 1399 } 1400 1401 void klassVtable::verify(outputStream* st, bool forced) { 1402 // make sure table is initialized 1403 if (!Universe::is_fully_initialized()) return; 1404 #ifndef PRODUCT 1405 // avoid redundant verifies 1406 if (!forced && _verify_count == Universe::verify_count()) return; 1407 _verify_count = Universe::verify_count(); 1408 #endif 1409 oop* end_of_obj = (oop*)_klass() + _klass()->size(); 1410 oop* end_of_vtable = (oop *)&table()[_length]; 1411 if (end_of_vtable > end_of_obj) { 1412 fatal("klass %s: klass object too short (vtable extends beyond end)", 1413 _klass->internal_name()); 1414 } 1415 1416 for (int i = 0; i < _length; i++) table()[i].verify(this, st); 1417 // verify consistency with superKlass vtable 1418 Klass* super = _klass->super(); 1419 if (super != NULL) { 1420 InstanceKlass* sk = InstanceKlass::cast(super); 1421 klassVtable* vt = sk->vtable(); 1422 for (int i = 0; i < vt->length(); i++) { 1423 verify_against(st, vt, i); 1424 } 1425 } 1426 } 1427 1428 void klassVtable::verify_against(outputStream* st, klassVtable* vt, int index) { 1429 vtableEntry* vte = &vt->table()[index]; 1430 if (vte->method()->name() != table()[index].method()->name() || 1431 vte->method()->signature() != table()[index].method()->signature()) { 1432 fatal("mismatched name/signature of vtable entries"); 1433 } 1434 } 1435 1436 #ifndef PRODUCT 1437 void klassVtable::print() { 1438 ResourceMark rm; 1439 tty->print("klassVtable for klass %s (length %d):\n", _klass->internal_name(), length()); 1440 for (int i = 0; i < length(); i++) { 1441 table()[i].print(); 1442 tty->cr(); 1443 } 1444 } 1445 #endif 1446 1447 void vtableEntry::verify(klassVtable* vt, outputStream* st) { 1448 NOT_PRODUCT(FlagSetting fs(IgnoreLockingAssertions, true)); 1449 assert(method() != NULL, "must have set method"); 1450 method()->verify(); 1451 // we sub_type, because it could be a miranda method 1452 if (!vt->klass()->is_subtype_of(method()->method_holder())) { 1453 #ifndef PRODUCT 1454 print(); 1455 #endif 1456 fatal("vtableEntry " PTR_FORMAT ": method is from subclass", p2i(this)); 1457 } 1458 } 1459 1460 #ifndef PRODUCT 1461 1462 void vtableEntry::print() { 1463 ResourceMark rm; 1464 tty->print("vtableEntry %s: ", method()->name()->as_C_string()); 1465 if (Verbose) { 1466 tty->print("m " PTR_FORMAT " ", p2i(method())); 1467 } 1468 } 1469 1470 class VtableStats : AllStatic { 1471 public: 1472 static int no_klasses; // # classes with vtables 1473 static int no_array_klasses; // # array classes 1474 static int no_instance_klasses; // # instanceKlasses 1475 static int sum_of_vtable_len; // total # of vtable entries 1476 static int sum_of_array_vtable_len; // total # of vtable entries in array klasses only 1477 static int fixed; // total fixed overhead in bytes 1478 static int filler; // overhead caused by filler bytes 1479 static int entries; // total bytes consumed by vtable entries 1480 static int array_entries; // total bytes consumed by array vtable entries 1481 1482 static void do_class(Klass* k) { 1483 Klass* kl = k; 1484 klassVtable* vt = kl->vtable(); 1485 if (vt == NULL) return; 1486 no_klasses++; 1487 if (kl->is_instance_klass()) { 1488 no_instance_klasses++; 1489 kl->array_klasses_do(do_class); 1490 } 1491 if (kl->is_array_klass()) { 1492 no_array_klasses++; 1493 sum_of_array_vtable_len += vt->length(); 1494 } 1495 sum_of_vtable_len += vt->length(); 1496 } 1497 1498 static void compute() { 1499 SystemDictionary::classes_do(do_class); 1500 fixed = no_klasses * oopSize; // vtable length 1501 // filler size is a conservative approximation 1502 filler = oopSize * (no_klasses - no_instance_klasses) * (sizeof(InstanceKlass) - sizeof(ArrayKlass) - 1); 1503 entries = sizeof(vtableEntry) * sum_of_vtable_len; 1504 array_entries = sizeof(vtableEntry) * sum_of_array_vtable_len; 1505 } 1506 }; 1507 1508 int VtableStats::no_klasses = 0; 1509 int VtableStats::no_array_klasses = 0; 1510 int VtableStats::no_instance_klasses = 0; 1511 int VtableStats::sum_of_vtable_len = 0; 1512 int VtableStats::sum_of_array_vtable_len = 0; 1513 int VtableStats::fixed = 0; 1514 int VtableStats::filler = 0; 1515 int VtableStats::entries = 0; 1516 int VtableStats::array_entries = 0; 1517 1518 void klassVtable::print_statistics() { 1519 ResourceMark rm; 1520 HandleMark hm; 1521 VtableStats::compute(); 1522 tty->print_cr("vtable statistics:"); 1523 tty->print_cr("%6d classes (%d instance, %d array)", VtableStats::no_klasses, VtableStats::no_instance_klasses, VtableStats::no_array_klasses); 1524 int total = VtableStats::fixed + VtableStats::filler + VtableStats::entries; 1525 tty->print_cr("%6d bytes fixed overhead (refs + vtable object header)", VtableStats::fixed); 1526 tty->print_cr("%6d bytes filler overhead", VtableStats::filler); 1527 tty->print_cr("%6d bytes for vtable entries (%d for arrays)", VtableStats::entries, VtableStats::array_entries); 1528 tty->print_cr("%6d bytes total", total); 1529 } 1530 1531 int klassItable::_total_classes; // Total no. of classes with itables 1532 long klassItable::_total_size; // Total no. of bytes used for itables 1533 1534 void klassItable::print_statistics() { 1535 tty->print_cr("itable statistics:"); 1536 tty->print_cr("%6d classes with itables", _total_classes); 1537 tty->print_cr("%6lu K uses for itables (average by class: %ld bytes)", _total_size / K, _total_size / _total_classes); 1538 } 1539 1540 #endif // PRODUCT