1 /* 2 * Copyright (c) 2003, 2022, 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 "cds/metaspaceShared.hpp" 27 #include "classfile/classFileStream.hpp" 28 #include "classfile/classLoaderDataGraph.hpp" 29 #include "classfile/classLoadInfo.hpp" 30 #include "classfile/javaClasses.inline.hpp" 31 #include "classfile/metadataOnStackMark.hpp" 32 #include "classfile/symbolTable.hpp" 33 #include "classfile/klassFactory.hpp" 34 #include "classfile/verifier.hpp" 35 #include "classfile/vmClasses.hpp" 36 #include "classfile/vmSymbols.hpp" 37 #include "code/codeCache.hpp" 38 #include "compiler/compileBroker.hpp" 39 #include "interpreter/oopMapCache.hpp" 40 #include "interpreter/rewriter.hpp" 41 #include "jfr/jfrEvents.hpp" 42 #include "logging/logStream.hpp" 43 #include "memory/metadataFactory.hpp" 44 #include "memory/resourceArea.hpp" 45 #include "memory/universe.hpp" 46 #include "oops/annotations.hpp" 47 #include "oops/constantPool.hpp" 48 #include "oops/fieldStreams.inline.hpp" 49 #include "oops/klass.inline.hpp" 50 #include "oops/klassVtable.hpp" 51 #include "oops/oop.inline.hpp" 52 #include "oops/recordComponent.hpp" 53 #include "prims/jvmtiImpl.hpp" 54 #include "prims/jvmtiRedefineClasses.hpp" 55 #include "prims/jvmtiThreadState.inline.hpp" 56 #include "prims/resolvedMethodTable.hpp" 57 #include "prims/methodComparator.hpp" 58 #include "runtime/atomic.hpp" 59 #include "runtime/deoptimization.hpp" 60 #include "runtime/handles.inline.hpp" 61 #include "runtime/jniHandles.inline.hpp" 62 #include "runtime/relocator.hpp" 63 #include "runtime/safepointVerifiers.hpp" 64 #include "utilities/bitMap.inline.hpp" 65 #include "utilities/events.hpp" 66 67 Array<Method*>* VM_RedefineClasses::_old_methods = NULL; 68 Array<Method*>* VM_RedefineClasses::_new_methods = NULL; 69 Method** VM_RedefineClasses::_matching_old_methods = NULL; 70 Method** VM_RedefineClasses::_matching_new_methods = NULL; 71 Method** VM_RedefineClasses::_deleted_methods = NULL; 72 Method** VM_RedefineClasses::_added_methods = NULL; 73 int VM_RedefineClasses::_matching_methods_length = 0; 74 int VM_RedefineClasses::_deleted_methods_length = 0; 75 int VM_RedefineClasses::_added_methods_length = 0; 76 77 // This flag is global as the constructor does not reset it: 78 bool VM_RedefineClasses::_has_redefined_Object = false; 79 u8 VM_RedefineClasses::_id_counter = 0; 80 81 VM_RedefineClasses::VM_RedefineClasses(jint class_count, 82 const jvmtiClassDefinition *class_defs, 83 JvmtiClassLoadKind class_load_kind) { 84 _class_count = class_count; 85 _class_defs = class_defs; 86 _class_load_kind = class_load_kind; 87 _any_class_has_resolved_methods = false; 88 _res = JVMTI_ERROR_NONE; 89 _the_class = NULL; 90 _id = next_id(); 91 } 92 93 static inline InstanceKlass* get_ik(jclass def) { 94 oop mirror = JNIHandles::resolve_non_null(def); 95 return InstanceKlass::cast(java_lang_Class::as_Klass(mirror)); 96 } 97 98 // If any of the classes are being redefined, wait 99 // Parallel constant pool merging leads to indeterminate constant pools. 100 void VM_RedefineClasses::lock_classes() { 101 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current()); 102 GrowableArray<Klass*>* redef_classes = state->get_classes_being_redefined(); 103 104 MonitorLocker ml(RedefineClasses_lock); 105 106 if (redef_classes == NULL) { 107 redef_classes = new (mtClass) GrowableArray<Klass*>(1, mtClass); 108 state->set_classes_being_redefined(redef_classes); 109 } 110 111 bool has_redefined; 112 do { 113 has_redefined = false; 114 // Go through classes each time until none are being redefined. Skip 115 // the ones that are being redefined by this thread currently. Class file 116 // load hook event may trigger new class redefine when we are redefining 117 // a class (after lock_classes()). 118 for (int i = 0; i < _class_count; i++) { 119 InstanceKlass* ik = get_ik(_class_defs[i].klass); 120 // Check if we are currently redefining the class in this thread already. 121 if (redef_classes->contains(ik)) { 122 assert(ik->is_being_redefined(), "sanity"); 123 } else { 124 if (ik->is_being_redefined()) { 125 ml.wait(); 126 has_redefined = true; 127 break; // for loop 128 } 129 } 130 } 131 } while (has_redefined); 132 133 for (int i = 0; i < _class_count; i++) { 134 InstanceKlass* ik = get_ik(_class_defs[i].klass); 135 redef_classes->push(ik); // Add to the _classes_being_redefined list 136 ik->set_is_being_redefined(true); 137 } 138 ml.notify_all(); 139 } 140 141 void VM_RedefineClasses::unlock_classes() { 142 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current()); 143 GrowableArray<Klass*>* redef_classes = state->get_classes_being_redefined(); 144 assert(redef_classes != NULL, "_classes_being_redefined is not allocated"); 145 146 MonitorLocker ml(RedefineClasses_lock); 147 148 for (int i = _class_count - 1; i >= 0; i--) { 149 InstanceKlass* def_ik = get_ik(_class_defs[i].klass); 150 if (redef_classes->length() > 0) { 151 // Remove the class from _classes_being_redefined list 152 Klass* k = redef_classes->pop(); 153 assert(def_ik == k, "unlocking wrong class"); 154 } 155 assert(def_ik->is_being_redefined(), 156 "should be being redefined to get here"); 157 158 // Unlock after we finish all redefines for this class within 159 // the thread. Same class can be pushed to the list multiple 160 // times (not more than once by each recursive redefinition). 161 if (!redef_classes->contains(def_ik)) { 162 def_ik->set_is_being_redefined(false); 163 } 164 } 165 ml.notify_all(); 166 } 167 168 bool VM_RedefineClasses::doit_prologue() { 169 if (_class_count == 0) { 170 _res = JVMTI_ERROR_NONE; 171 return false; 172 } 173 if (_class_defs == NULL) { 174 _res = JVMTI_ERROR_NULL_POINTER; 175 return false; 176 } 177 178 for (int i = 0; i < _class_count; i++) { 179 if (_class_defs[i].klass == NULL) { 180 _res = JVMTI_ERROR_INVALID_CLASS; 181 return false; 182 } 183 if (_class_defs[i].class_byte_count == 0) { 184 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT; 185 return false; 186 } 187 if (_class_defs[i].class_bytes == NULL) { 188 _res = JVMTI_ERROR_NULL_POINTER; 189 return false; 190 } 191 192 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass); 193 // classes for primitives, arrays, and hidden classes 194 // cannot be redefined. 195 if (!is_modifiable_class(mirror)) { 196 _res = JVMTI_ERROR_UNMODIFIABLE_CLASS; 197 return false; 198 } 199 } 200 201 // Start timer after all the sanity checks; not quite accurate, but 202 // better than adding a bunch of stop() calls. 203 if (log_is_enabled(Info, redefine, class, timer)) { 204 _timer_vm_op_prologue.start(); 205 } 206 207 lock_classes(); 208 // We first load new class versions in the prologue, because somewhere down the 209 // call chain it is required that the current thread is a Java thread. 210 _res = load_new_class_versions(); 211 if (_res != JVMTI_ERROR_NONE) { 212 // free any successfully created classes, since none are redefined 213 for (int i = 0; i < _class_count; i++) { 214 if (_scratch_classes[i] != NULL) { 215 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data(); 216 // Free the memory for this class at class unloading time. Not before 217 // because CMS might think this is still live. 218 InstanceKlass* ik = get_ik(_class_defs[i].klass); 219 if (ik->get_cached_class_file() == _scratch_classes[i]->get_cached_class_file()) { 220 // Don't double-free cached_class_file copied from the original class if error. 221 _scratch_classes[i]->set_cached_class_file(NULL); 222 } 223 cld->add_to_deallocate_list(InstanceKlass::cast(_scratch_classes[i])); 224 } 225 } 226 // Free os::malloc allocated memory in load_new_class_version. 227 os::free(_scratch_classes); 228 _timer_vm_op_prologue.stop(); 229 unlock_classes(); 230 return false; 231 } 232 233 _timer_vm_op_prologue.stop(); 234 return true; 235 } 236 237 void VM_RedefineClasses::doit() { 238 Thread* current = Thread::current(); 239 240 if (log_is_enabled(Info, redefine, class, timer)) { 241 _timer_vm_op_doit.start(); 242 } 243 244 #if INCLUDE_CDS 245 if (UseSharedSpaces) { 246 // Sharing is enabled so we remap the shared readonly space to 247 // shared readwrite, private just in case we need to redefine 248 // a shared class. We do the remap during the doit() phase of 249 // the safepoint to be safer. 250 if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) { 251 log_info(redefine, class, load)("failed to remap shared readonly space to readwrite, private"); 252 _res = JVMTI_ERROR_INTERNAL; 253 _timer_vm_op_doit.stop(); 254 return; 255 } 256 } 257 #endif 258 259 // Mark methods seen on stack and everywhere else so old methods are not 260 // cleaned up if they're on the stack. 261 MetadataOnStackMark md_on_stack(/*walk_all_metadata*/true, /*redefinition_walk*/true); 262 HandleMark hm(current); // make sure any handles created are deleted 263 // before the stack walk again. 264 265 for (int i = 0; i < _class_count; i++) { 266 redefine_single_class(current, _class_defs[i].klass, _scratch_classes[i]); 267 } 268 269 // Flush all compiled code that depends on the classes redefined. 270 flush_dependent_code(); 271 272 // Adjust constantpool caches and vtables for all classes 273 // that reference methods of the evolved classes. 274 // Have to do this after all classes are redefined and all methods that 275 // are redefined are marked as old. 276 AdjustAndCleanMetadata adjust_and_clean_metadata(current); 277 ClassLoaderDataGraph::classes_do(&adjust_and_clean_metadata); 278 279 // JSR-292 support 280 if (_any_class_has_resolved_methods) { 281 bool trace_name_printed = false; 282 ResolvedMethodTable::adjust_method_entries(&trace_name_printed); 283 } 284 285 // Increment flag indicating that some invariants are no longer true. 286 // See jvmtiExport.hpp for detailed explanation. 287 JvmtiExport::increment_redefinition_count(); 288 289 // check_class() is optionally called for product bits, but is 290 // always called for non-product bits. 291 #ifdef PRODUCT 292 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 293 #endif 294 log_trace(redefine, class, obsolete, metadata)("calling check_class"); 295 CheckClass check_class(current); 296 ClassLoaderDataGraph::classes_do(&check_class); 297 #ifdef PRODUCT 298 } 299 #endif 300 301 // Clean up any metadata now unreferenced while MetadataOnStackMark is set. 302 ClassLoaderDataGraph::clean_deallocate_lists(false); 303 304 _timer_vm_op_doit.stop(); 305 } 306 307 void VM_RedefineClasses::doit_epilogue() { 308 unlock_classes(); 309 310 // Free os::malloc allocated memory. 311 os::free(_scratch_classes); 312 313 // Reset the_class to null for error printing. 314 _the_class = NULL; 315 316 if (log_is_enabled(Info, redefine, class, timer)) { 317 // Used to have separate timers for "doit" and "all", but the timer 318 // overhead skewed the measurements. 319 julong doit_time = _timer_vm_op_doit.milliseconds(); 320 julong all_time = _timer_vm_op_prologue.milliseconds() + doit_time; 321 322 log_info(redefine, class, timer) 323 ("vm_op: all=" JULONG_FORMAT " prologue=" JULONG_FORMAT " doit=" JULONG_FORMAT, 324 all_time, (julong)_timer_vm_op_prologue.milliseconds(), doit_time); 325 log_info(redefine, class, timer) 326 ("redefine_single_class: phase1=" JULONG_FORMAT " phase2=" JULONG_FORMAT, 327 (julong)_timer_rsc_phase1.milliseconds(), (julong)_timer_rsc_phase2.milliseconds()); 328 } 329 } 330 331 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) { 332 // classes for primitives cannot be redefined 333 if (java_lang_Class::is_primitive(klass_mirror)) { 334 return false; 335 } 336 Klass* k = java_lang_Class::as_Klass(klass_mirror); 337 // classes for arrays cannot be redefined 338 if (k == NULL || !k->is_instance_klass()) { 339 return false; 340 } 341 342 // Cannot redefine or retransform a hidden class. 343 if (InstanceKlass::cast(k)->is_hidden()) { 344 return false; 345 } 346 return true; 347 } 348 349 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p 350 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For 351 // direct CP entries, there is just the current entry to append. For 352 // indirect and double-indirect CP entries, there are zero or more 353 // referenced CP entries along with the current entry to append. 354 // Indirect and double-indirect CP entries are handled by recursive 355 // calls to append_entry() as needed. The referenced CP entries are 356 // always appended to *merge_cp_p before the referee CP entry. These 357 // referenced CP entries may already exist in *merge_cp_p in which case 358 // there is nothing extra to append and only the current entry is 359 // appended. 360 void VM_RedefineClasses::append_entry(const constantPoolHandle& scratch_cp, 361 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) { 362 363 // append is different depending on entry tag type 364 switch (scratch_cp->tag_at(scratch_i).value()) { 365 366 // The old verifier is implemented outside the VM. It loads classes, 367 // but does not resolve constant pool entries directly so we never 368 // see Class entries here with the old verifier. Similarly the old 369 // verifier does not like Class entries in the input constant pool. 370 // The split-verifier is implemented in the VM so it can optionally 371 // and directly resolve constant pool entries to load classes. The 372 // split-verifier can accept either Class entries or UnresolvedClass 373 // entries in the input constant pool. We revert the appended copy 374 // back to UnresolvedClass so that either verifier will be happy 375 // with the constant pool entry. 376 // 377 // this is an indirect CP entry so it needs special handling 378 case JVM_CONSTANT_Class: 379 case JVM_CONSTANT_UnresolvedClass: 380 { 381 int name_i = scratch_cp->klass_name_index_at(scratch_i); 382 int new_name_i = find_or_append_indirect_entry(scratch_cp, name_i, merge_cp_p, 383 merge_cp_length_p); 384 385 if (new_name_i != name_i) { 386 log_trace(redefine, class, constantpool) 387 ("Class entry@%d name_index change: %d to %d", 388 *merge_cp_length_p, name_i, new_name_i); 389 } 390 391 (*merge_cp_p)->temp_unresolved_klass_at_put(*merge_cp_length_p, new_name_i); 392 if (scratch_i != *merge_cp_length_p) { 393 // The new entry in *merge_cp_p is at a different index than 394 // the new entry in scratch_cp so we need to map the index values. 395 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 396 } 397 (*merge_cp_length_p)++; 398 } break; 399 400 // these are direct CP entries so they can be directly appended, 401 // but double and long take two constant pool entries 402 case JVM_CONSTANT_Double: // fall through 403 case JVM_CONSTANT_Long: 404 { 405 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p); 406 407 if (scratch_i != *merge_cp_length_p) { 408 // The new entry in *merge_cp_p is at a different index than 409 // the new entry in scratch_cp so we need to map the index values. 410 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 411 } 412 (*merge_cp_length_p) += 2; 413 } break; 414 415 // these are direct CP entries so they can be directly appended 416 case JVM_CONSTANT_Float: // fall through 417 case JVM_CONSTANT_Integer: // fall through 418 case JVM_CONSTANT_Utf8: // fall through 419 420 // This was an indirect CP entry, but it has been changed into 421 // Symbol*s so this entry can be directly appended. 422 case JVM_CONSTANT_String: // fall through 423 { 424 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p); 425 426 if (scratch_i != *merge_cp_length_p) { 427 // The new entry in *merge_cp_p is at a different index than 428 // the new entry in scratch_cp so we need to map the index values. 429 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 430 } 431 (*merge_cp_length_p)++; 432 } break; 433 434 // this is an indirect CP entry so it needs special handling 435 case JVM_CONSTANT_NameAndType: 436 { 437 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i); 438 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p, 439 merge_cp_length_p); 440 441 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i); 442 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i, 443 merge_cp_p, merge_cp_length_p); 444 445 // If the referenced entries already exist in *merge_cp_p, then 446 // both new_name_ref_i and new_signature_ref_i will both be 0. 447 // In that case, all we are appending is the current entry. 448 if (new_name_ref_i != name_ref_i) { 449 log_trace(redefine, class, constantpool) 450 ("NameAndType entry@%d name_ref_index change: %d to %d", 451 *merge_cp_length_p, name_ref_i, new_name_ref_i); 452 } 453 if (new_signature_ref_i != signature_ref_i) { 454 log_trace(redefine, class, constantpool) 455 ("NameAndType entry@%d signature_ref_index change: %d to %d", 456 *merge_cp_length_p, signature_ref_i, new_signature_ref_i); 457 } 458 459 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p, 460 new_name_ref_i, new_signature_ref_i); 461 if (scratch_i != *merge_cp_length_p) { 462 // The new entry in *merge_cp_p is at a different index than 463 // the new entry in scratch_cp so we need to map the index values. 464 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 465 } 466 (*merge_cp_length_p)++; 467 } break; 468 469 // this is a double-indirect CP entry so it needs special handling 470 case JVM_CONSTANT_Fieldref: // fall through 471 case JVM_CONSTANT_InterfaceMethodref: // fall through 472 case JVM_CONSTANT_Methodref: 473 { 474 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i); 475 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i, 476 merge_cp_p, merge_cp_length_p); 477 478 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i); 479 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i, 480 merge_cp_p, merge_cp_length_p); 481 482 const char *entry_name = NULL; 483 switch (scratch_cp->tag_at(scratch_i).value()) { 484 case JVM_CONSTANT_Fieldref: 485 entry_name = "Fieldref"; 486 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i, 487 new_name_and_type_ref_i); 488 break; 489 case JVM_CONSTANT_InterfaceMethodref: 490 entry_name = "IFMethodref"; 491 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p, 492 new_klass_ref_i, new_name_and_type_ref_i); 493 break; 494 case JVM_CONSTANT_Methodref: 495 entry_name = "Methodref"; 496 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i, 497 new_name_and_type_ref_i); 498 break; 499 default: 500 guarantee(false, "bad switch"); 501 break; 502 } 503 504 if (klass_ref_i != new_klass_ref_i) { 505 log_trace(redefine, class, constantpool) 506 ("%s entry@%d class_index changed: %d to %d", entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i); 507 } 508 if (name_and_type_ref_i != new_name_and_type_ref_i) { 509 log_trace(redefine, class, constantpool) 510 ("%s entry@%d name_and_type_index changed: %d to %d", 511 entry_name, *merge_cp_length_p, name_and_type_ref_i, new_name_and_type_ref_i); 512 } 513 514 if (scratch_i != *merge_cp_length_p) { 515 // The new entry in *merge_cp_p is at a different index than 516 // the new entry in scratch_cp so we need to map the index values. 517 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 518 } 519 (*merge_cp_length_p)++; 520 } break; 521 522 // this is an indirect CP entry so it needs special handling 523 case JVM_CONSTANT_MethodType: 524 { 525 int ref_i = scratch_cp->method_type_index_at(scratch_i); 526 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p, 527 merge_cp_length_p); 528 if (new_ref_i != ref_i) { 529 log_trace(redefine, class, constantpool) 530 ("MethodType entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i); 531 } 532 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i); 533 if (scratch_i != *merge_cp_length_p) { 534 // The new entry in *merge_cp_p is at a different index than 535 // the new entry in scratch_cp so we need to map the index values. 536 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 537 } 538 (*merge_cp_length_p)++; 539 } break; 540 541 // this is an indirect CP entry so it needs special handling 542 case JVM_CONSTANT_MethodHandle: 543 { 544 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i); 545 int ref_i = scratch_cp->method_handle_index_at(scratch_i); 546 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p, 547 merge_cp_length_p); 548 if (new_ref_i != ref_i) { 549 log_trace(redefine, class, constantpool) 550 ("MethodHandle entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i); 551 } 552 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i); 553 if (scratch_i != *merge_cp_length_p) { 554 // The new entry in *merge_cp_p is at a different index than 555 // the new entry in scratch_cp so we need to map the index values. 556 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 557 } 558 (*merge_cp_length_p)++; 559 } break; 560 561 // this is an indirect CP entry so it needs special handling 562 case JVM_CONSTANT_Dynamic: // fall through 563 case JVM_CONSTANT_InvokeDynamic: 564 { 565 // Index of the bootstrap specifier in the operands array 566 int old_bs_i = scratch_cp->bootstrap_methods_attribute_index(scratch_i); 567 int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p, 568 merge_cp_length_p); 569 // The bootstrap method NameAndType_info index 570 int old_ref_i = scratch_cp->bootstrap_name_and_type_ref_index_at(scratch_i); 571 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p, 572 merge_cp_length_p); 573 if (new_bs_i != old_bs_i) { 574 log_trace(redefine, class, constantpool) 575 ("Dynamic entry@%d bootstrap_method_attr_index change: %d to %d", 576 *merge_cp_length_p, old_bs_i, new_bs_i); 577 } 578 if (new_ref_i != old_ref_i) { 579 log_trace(redefine, class, constantpool) 580 ("Dynamic entry@%d name_and_type_index change: %d to %d", *merge_cp_length_p, old_ref_i, new_ref_i); 581 } 582 583 if (scratch_cp->tag_at(scratch_i).is_dynamic_constant()) 584 (*merge_cp_p)->dynamic_constant_at_put(*merge_cp_length_p, new_bs_i, new_ref_i); 585 else 586 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i); 587 if (scratch_i != *merge_cp_length_p) { 588 // The new entry in *merge_cp_p is at a different index than 589 // the new entry in scratch_cp so we need to map the index values. 590 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 591 } 592 (*merge_cp_length_p)++; 593 } break; 594 595 // At this stage, Class or UnresolvedClass could be in scratch_cp, but not 596 // ClassIndex 597 case JVM_CONSTANT_ClassIndex: // fall through 598 599 // Invalid is used as the tag for the second constant pool entry 600 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should 601 // not be seen by itself. 602 case JVM_CONSTANT_Invalid: // fall through 603 604 // At this stage, String could be here, but not StringIndex 605 case JVM_CONSTANT_StringIndex: // fall through 606 607 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be 608 // here 609 case JVM_CONSTANT_UnresolvedClassInError: // fall through 610 611 default: 612 { 613 // leave a breadcrumb 614 jbyte bad_value = scratch_cp->tag_at(scratch_i).value(); 615 ShouldNotReachHere(); 616 } break; 617 } // end switch tag value 618 } // end append_entry() 619 620 621 int VM_RedefineClasses::find_or_append_indirect_entry(const constantPoolHandle& scratch_cp, 622 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) { 623 624 int new_ref_i = ref_i; 625 bool match = (ref_i < *merge_cp_length_p) && 626 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i); 627 628 if (!match) { 629 // forward reference in *merge_cp_p or not a direct match 630 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p); 631 if (found_i != 0) { 632 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree"); 633 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry. 634 new_ref_i = found_i; 635 map_index(scratch_cp, ref_i, found_i); 636 } else { 637 // no match found so we have to append this entry to *merge_cp_p 638 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p); 639 // The above call to append_entry() can only append one entry 640 // so the post call query of *merge_cp_length_p is only for 641 // the sake of consistency. 642 new_ref_i = *merge_cp_length_p - 1; 643 } 644 } 645 646 return new_ref_i; 647 } // end find_or_append_indirect_entry() 648 649 650 // Append a bootstrap specifier into the merge_cp operands that is semantically equal 651 // to the scratch_cp operands bootstrap specifier passed by the old_bs_i index. 652 // Recursively append new merge_cp entries referenced by the new bootstrap specifier. 653 void VM_RedefineClasses::append_operand(const constantPoolHandle& scratch_cp, int old_bs_i, 654 constantPoolHandle *merge_cp_p, int *merge_cp_length_p) { 655 656 int old_ref_i = scratch_cp->operand_bootstrap_method_ref_index_at(old_bs_i); 657 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p, 658 merge_cp_length_p); 659 if (new_ref_i != old_ref_i) { 660 log_trace(redefine, class, constantpool) 661 ("operands entry@%d bootstrap method ref_index change: %d to %d", _operands_cur_length, old_ref_i, new_ref_i); 662 } 663 664 Array<u2>* merge_ops = (*merge_cp_p)->operands(); 665 int new_bs_i = _operands_cur_length; 666 // We have _operands_cur_length == 0 when the merge_cp operands is empty yet. 667 // However, the operand_offset_at(0) was set in the extend_operands() call. 668 int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0) 669 : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1); 670 int argc = scratch_cp->operand_argument_count_at(old_bs_i); 671 672 ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base); 673 merge_ops->at_put(new_base++, new_ref_i); 674 merge_ops->at_put(new_base++, argc); 675 676 for (int i = 0; i < argc; i++) { 677 int old_arg_ref_i = scratch_cp->operand_argument_index_at(old_bs_i, i); 678 int new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p, 679 merge_cp_length_p); 680 merge_ops->at_put(new_base++, new_arg_ref_i); 681 if (new_arg_ref_i != old_arg_ref_i) { 682 log_trace(redefine, class, constantpool) 683 ("operands entry@%d bootstrap method argument ref_index change: %d to %d", 684 _operands_cur_length, old_arg_ref_i, new_arg_ref_i); 685 } 686 } 687 if (old_bs_i != _operands_cur_length) { 688 // The bootstrap specifier in *merge_cp_p is at a different index than 689 // that in scratch_cp so we need to map the index values. 690 map_operand_index(old_bs_i, new_bs_i); 691 } 692 _operands_cur_length++; 693 } // end append_operand() 694 695 696 int VM_RedefineClasses::find_or_append_operand(const constantPoolHandle& scratch_cp, 697 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) { 698 699 int new_bs_i = old_bs_i; // bootstrap specifier index 700 bool match = (old_bs_i < _operands_cur_length) && 701 scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i); 702 703 if (!match) { 704 // forward reference in *merge_cp_p or not a direct match 705 int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p, 706 _operands_cur_length); 707 if (found_i != -1) { 708 guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree"); 709 // found a matching operand somewhere else in *merge_cp_p so just need a mapping 710 new_bs_i = found_i; 711 map_operand_index(old_bs_i, found_i); 712 } else { 713 // no match found so we have to append this bootstrap specifier to *merge_cp_p 714 append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p); 715 new_bs_i = _operands_cur_length - 1; 716 } 717 } 718 return new_bs_i; 719 } // end find_or_append_operand() 720 721 722 void VM_RedefineClasses::finalize_operands_merge(const constantPoolHandle& merge_cp, TRAPS) { 723 if (merge_cp->operands() == NULL) { 724 return; 725 } 726 // Shrink the merge_cp operands 727 merge_cp->shrink_operands(_operands_cur_length, CHECK); 728 729 if (log_is_enabled(Trace, redefine, class, constantpool)) { 730 // don't want to loop unless we are tracing 731 int count = 0; 732 for (int i = 1; i < _operands_index_map_p->length(); i++) { 733 int value = _operands_index_map_p->at(i); 734 if (value != -1) { 735 log_trace(redefine, class, constantpool)("operands_index_map[%d]: old=%d new=%d", count, i, value); 736 count++; 737 } 738 } 739 } 740 // Clean-up 741 _operands_index_map_p = NULL; 742 _operands_cur_length = 0; 743 _operands_index_map_count = 0; 744 } // end finalize_operands_merge() 745 746 // Symbol* comparator for qsort 747 // The caller must have an active ResourceMark. 748 static int symcmp(const void* a, const void* b) { 749 char* astr = (*(Symbol**)a)->as_C_string(); 750 char* bstr = (*(Symbol**)b)->as_C_string(); 751 return strcmp(astr, bstr); 752 } 753 754 // The caller must have an active ResourceMark. 755 static jvmtiError check_attribute_arrays(const char* attr_name, 756 InstanceKlass* the_class, InstanceKlass* scratch_class, 757 Array<u2>* the_array, Array<u2>* scr_array) { 758 bool the_array_exists = the_array != Universe::the_empty_short_array(); 759 bool scr_array_exists = scr_array != Universe::the_empty_short_array(); 760 761 int array_len = the_array->length(); 762 if (the_array_exists && scr_array_exists) { 763 if (array_len != scr_array->length()) { 764 log_trace(redefine, class) 765 ("redefined class %s attribute change error: %s len=%d changed to len=%d", 766 the_class->external_name(), attr_name, array_len, scr_array->length()); 767 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 768 } 769 770 // The order of entries in the attribute array is not specified so we 771 // have to explicitly check for the same contents. We do this by copying 772 // the referenced symbols into their own arrays, sorting them and then 773 // comparing each element pair. 774 775 Symbol** the_syms = NEW_RESOURCE_ARRAY_RETURN_NULL(Symbol*, array_len); 776 Symbol** scr_syms = NEW_RESOURCE_ARRAY_RETURN_NULL(Symbol*, array_len); 777 778 if (the_syms == NULL || scr_syms == NULL) { 779 return JVMTI_ERROR_OUT_OF_MEMORY; 780 } 781 782 for (int i = 0; i < array_len; i++) { 783 int the_cp_index = the_array->at(i); 784 int scr_cp_index = scr_array->at(i); 785 the_syms[i] = the_class->constants()->klass_name_at(the_cp_index); 786 scr_syms[i] = scratch_class->constants()->klass_name_at(scr_cp_index); 787 } 788 789 qsort(the_syms, array_len, sizeof(Symbol*), symcmp); 790 qsort(scr_syms, array_len, sizeof(Symbol*), symcmp); 791 792 for (int i = 0; i < array_len; i++) { 793 if (the_syms[i] != scr_syms[i]) { 794 log_info(redefine, class) 795 ("redefined class %s attribute change error: %s[%d]: %s changed to %s", 796 the_class->external_name(), attr_name, i, 797 the_syms[i]->as_C_string(), scr_syms[i]->as_C_string()); 798 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 799 } 800 } 801 } else if (the_array_exists ^ scr_array_exists) { 802 const char* action_str = (the_array_exists) ? "removed" : "added"; 803 log_info(redefine, class) 804 ("redefined class %s attribute change error: %s attribute %s", 805 the_class->external_name(), attr_name, action_str); 806 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 807 } 808 return JVMTI_ERROR_NONE; 809 } 810 811 static jvmtiError check_nest_attributes(InstanceKlass* the_class, 812 InstanceKlass* scratch_class) { 813 // Check whether the class NestHost attribute has been changed. 814 Thread* thread = Thread::current(); 815 ResourceMark rm(thread); 816 u2 the_nest_host_idx = the_class->nest_host_index(); 817 u2 scr_nest_host_idx = scratch_class->nest_host_index(); 818 819 if (the_nest_host_idx != 0 && scr_nest_host_idx != 0) { 820 Symbol* the_sym = the_class->constants()->klass_name_at(the_nest_host_idx); 821 Symbol* scr_sym = scratch_class->constants()->klass_name_at(scr_nest_host_idx); 822 if (the_sym != scr_sym) { 823 log_info(redefine, class, nestmates) 824 ("redefined class %s attribute change error: NestHost class: %s replaced with: %s", 825 the_class->external_name(), the_sym->as_C_string(), scr_sym->as_C_string()); 826 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 827 } 828 } else if ((the_nest_host_idx == 0) ^ (scr_nest_host_idx == 0)) { 829 const char* action_str = (the_nest_host_idx != 0) ? "removed" : "added"; 830 log_info(redefine, class, nestmates) 831 ("redefined class %s attribute change error: NestHost attribute %s", 832 the_class->external_name(), action_str); 833 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 834 } 835 836 // Check whether the class NestMembers attribute has been changed. 837 return check_attribute_arrays("NestMembers", 838 the_class, scratch_class, 839 the_class->nest_members(), 840 scratch_class->nest_members()); 841 } 842 843 // Return an error status if the class Record attribute was changed. 844 static jvmtiError check_record_attribute(InstanceKlass* the_class, InstanceKlass* scratch_class) { 845 // Get lists of record components. 846 Array<RecordComponent*>* the_record = the_class->record_components(); 847 Array<RecordComponent*>* scr_record = scratch_class->record_components(); 848 bool the_record_exists = the_record != NULL; 849 bool scr_record_exists = scr_record != NULL; 850 851 if (the_record_exists && scr_record_exists) { 852 int the_num_components = the_record->length(); 853 int scr_num_components = scr_record->length(); 854 if (the_num_components != scr_num_components) { 855 log_info(redefine, class, record) 856 ("redefined class %s attribute change error: Record num_components=%d changed to num_components=%d", 857 the_class->external_name(), the_num_components, scr_num_components); 858 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 859 } 860 861 // Compare each field in each record component. 862 ConstantPool* the_cp = the_class->constants(); 863 ConstantPool* scr_cp = scratch_class->constants(); 864 for (int x = 0; x < the_num_components; x++) { 865 RecordComponent* the_component = the_record->at(x); 866 RecordComponent* scr_component = scr_record->at(x); 867 const Symbol* const the_name = the_cp->symbol_at(the_component->name_index()); 868 const Symbol* const scr_name = scr_cp->symbol_at(scr_component->name_index()); 869 const Symbol* const the_descr = the_cp->symbol_at(the_component->descriptor_index()); 870 const Symbol* const scr_descr = scr_cp->symbol_at(scr_component->descriptor_index()); 871 if (the_name != scr_name || the_descr != scr_descr) { 872 log_info(redefine, class, record) 873 ("redefined class %s attribute change error: Record name_index, descriptor_index, and/or attributes_count changed", 874 the_class->external_name()); 875 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 876 } 877 878 int the_gen_sig = the_component->generic_signature_index(); 879 int scr_gen_sig = scr_component->generic_signature_index(); 880 const Symbol* const the_gen_sig_sym = (the_gen_sig == 0 ? NULL : 881 the_cp->symbol_at(the_component->generic_signature_index())); 882 const Symbol* const scr_gen_sig_sym = (scr_gen_sig == 0 ? NULL : 883 scr_cp->symbol_at(scr_component->generic_signature_index())); 884 if (the_gen_sig_sym != scr_gen_sig_sym) { 885 log_info(redefine, class, record) 886 ("redefined class %s attribute change error: Record generic_signature attribute changed", 887 the_class->external_name()); 888 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 889 } 890 891 // It's okay if a record component's annotations were changed. 892 } 893 894 } else if (the_record_exists ^ scr_record_exists) { 895 const char* action_str = (the_record_exists) ? "removed" : "added"; 896 log_info(redefine, class, record) 897 ("redefined class %s attribute change error: Record attribute %s", 898 the_class->external_name(), action_str); 899 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 900 } 901 902 return JVMTI_ERROR_NONE; 903 } 904 905 906 static jvmtiError check_permitted_subclasses_attribute(InstanceKlass* the_class, 907 InstanceKlass* scratch_class) { 908 Thread* thread = Thread::current(); 909 ResourceMark rm(thread); 910 911 // Check whether the class PermittedSubclasses attribute has been changed. 912 return check_attribute_arrays("PermittedSubclasses", 913 the_class, scratch_class, 914 the_class->permitted_subclasses(), 915 scratch_class->permitted_subclasses()); 916 } 917 918 static bool can_add_or_delete(Method* m) { 919 // Compatibility mode 920 return (AllowRedefinitionToAddDeleteMethods && 921 (m->is_private() && (m->is_static() || m->is_final()))); 922 } 923 924 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions( 925 InstanceKlass* the_class, 926 InstanceKlass* scratch_class) { 927 int i; 928 929 // Check superclasses, or rather their names, since superclasses themselves can be 930 // requested to replace. 931 // Check for NULL superclass first since this might be java.lang.Object 932 if (the_class->super() != scratch_class->super() && 933 (the_class->super() == NULL || scratch_class->super() == NULL || 934 the_class->super()->name() != 935 scratch_class->super()->name())) { 936 log_info(redefine, class, normalize) 937 ("redefined class %s superclass change error: superclass changed from %s to %s.", 938 the_class->external_name(), 939 the_class->super() == NULL ? "NULL" : the_class->super()->external_name(), 940 scratch_class->super() == NULL ? "NULL" : scratch_class->super()->external_name()); 941 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 942 } 943 944 // Check if the number, names and order of directly implemented interfaces are the same. 945 // I think in principle we should just check if the sets of names of directly implemented 946 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the 947 // .java file, also changes in .class file) should not matter. However, comparing sets is 948 // technically a bit more difficult, and, more importantly, I am not sure at present that the 949 // order of interfaces does not matter on the implementation level, i.e. that the VM does not 950 // rely on it somewhere. 951 Array<InstanceKlass*>* k_interfaces = the_class->local_interfaces(); 952 Array<InstanceKlass*>* k_new_interfaces = scratch_class->local_interfaces(); 953 int n_intfs = k_interfaces->length(); 954 if (n_intfs != k_new_interfaces->length()) { 955 log_info(redefine, class, normalize) 956 ("redefined class %s interfaces change error: number of implemented interfaces changed from %d to %d.", 957 the_class->external_name(), n_intfs, k_new_interfaces->length()); 958 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 959 } 960 for (i = 0; i < n_intfs; i++) { 961 if (k_interfaces->at(i)->name() != 962 k_new_interfaces->at(i)->name()) { 963 log_info(redefine, class, normalize) 964 ("redefined class %s interfaces change error: interface changed from %s to %s.", 965 the_class->external_name(), 966 k_interfaces->at(i)->external_name(), k_new_interfaces->at(i)->external_name()); 967 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 968 } 969 } 970 971 // Check whether class is in the error init state. 972 if (the_class->is_in_error_state()) { 973 log_info(redefine, class, normalize) 974 ("redefined class %s is in error init state.", the_class->external_name()); 975 // TBD #5057930: special error code is needed in 1.6 976 return JVMTI_ERROR_INVALID_CLASS; 977 } 978 979 // Check whether the nest-related attributes have been changed. 980 jvmtiError err = check_nest_attributes(the_class, scratch_class); 981 if (err != JVMTI_ERROR_NONE) { 982 return err; 983 } 984 985 // Check whether the Record attribute has been changed. 986 err = check_record_attribute(the_class, scratch_class); 987 if (err != JVMTI_ERROR_NONE) { 988 return err; 989 } 990 991 // Check whether the PermittedSubclasses attribute has been changed. 992 err = check_permitted_subclasses_attribute(the_class, scratch_class); 993 if (err != JVMTI_ERROR_NONE) { 994 return err; 995 } 996 997 // Check whether class modifiers are the same. 998 jushort old_flags = (jushort) the_class->access_flags().get_flags(); 999 jushort new_flags = (jushort) scratch_class->access_flags().get_flags(); 1000 if (old_flags != new_flags) { 1001 log_info(redefine, class, normalize) 1002 ("redefined class %s modifiers change error: modifiers changed from %d to %d.", 1003 the_class->external_name(), old_flags, new_flags); 1004 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED; 1005 } 1006 1007 // Check if the number, names, types and order of fields declared in these classes 1008 // are the same. 1009 JavaFieldStream old_fs(the_class); 1010 JavaFieldStream new_fs(scratch_class); 1011 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) { 1012 // name and signature 1013 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index()); 1014 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index()); 1015 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index()); 1016 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index()); 1017 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) { 1018 log_info(redefine, class, normalize) 1019 ("redefined class %s fields change error: field %s %s changed to %s %s.", 1020 the_class->external_name(), 1021 sig_sym1->as_C_string(), name_sym1->as_C_string(), 1022 sig_sym2->as_C_string(), name_sym2->as_C_string()); 1023 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 1024 } 1025 // offset 1026 if (old_fs.offset() != new_fs.offset()) { 1027 log_info(redefine, class, normalize) 1028 ("redefined class %s field %s change error: offset changed from %d to %d.", 1029 the_class->external_name(), name_sym2->as_C_string(), old_fs.offset(), new_fs.offset()); 1030 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 1031 } 1032 // access 1033 old_flags = old_fs.access_flags().as_short(); 1034 new_flags = new_fs.access_flags().as_short(); 1035 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) { 1036 log_info(redefine, class, normalize) 1037 ("redefined class %s field %s change error: modifiers changed from %d to %d.", 1038 the_class->external_name(), name_sym2->as_C_string(), old_flags, new_flags); 1039 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 1040 } 1041 } 1042 1043 // If both streams aren't done then we have a differing number of 1044 // fields. 1045 if (!old_fs.done() || !new_fs.done()) { 1046 const char* action = old_fs.done() ? "added" : "deleted"; 1047 log_info(redefine, class, normalize) 1048 ("redefined class %s fields change error: some fields were %s.", 1049 the_class->external_name(), action); 1050 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 1051 } 1052 1053 // Do a parallel walk through the old and new methods. Detect 1054 // cases where they match (exist in both), have been added in 1055 // the new methods, or have been deleted (exist only in the 1056 // old methods). The class file parser places methods in order 1057 // by method name, but does not order overloaded methods by 1058 // signature. In order to determine what fate befell the methods, 1059 // this code places the overloaded new methods that have matching 1060 // old methods in the same order as the old methods and places 1061 // new overloaded methods at the end of overloaded methods of 1062 // that name. The code for this order normalization is adapted 1063 // from the algorithm used in InstanceKlass::find_method(). 1064 // Since we are swapping out of order entries as we find them, 1065 // we only have to search forward through the overloaded methods. 1066 // Methods which are added and have the same name as an existing 1067 // method (but different signature) will be put at the end of 1068 // the methods with that name, and the name mismatch code will 1069 // handle them. 1070 Array<Method*>* k_old_methods(the_class->methods()); 1071 Array<Method*>* k_new_methods(scratch_class->methods()); 1072 int n_old_methods = k_old_methods->length(); 1073 int n_new_methods = k_new_methods->length(); 1074 Thread* thread = Thread::current(); 1075 1076 int ni = 0; 1077 int oi = 0; 1078 while (true) { 1079 Method* k_old_method; 1080 Method* k_new_method; 1081 enum { matched, added, deleted, undetermined } method_was = undetermined; 1082 1083 if (oi >= n_old_methods) { 1084 if (ni >= n_new_methods) { 1085 break; // we've looked at everything, done 1086 } 1087 // New method at the end 1088 k_new_method = k_new_methods->at(ni); 1089 method_was = added; 1090 } else if (ni >= n_new_methods) { 1091 // Old method, at the end, is deleted 1092 k_old_method = k_old_methods->at(oi); 1093 method_was = deleted; 1094 } else { 1095 // There are more methods in both the old and new lists 1096 k_old_method = k_old_methods->at(oi); 1097 k_new_method = k_new_methods->at(ni); 1098 if (k_old_method->name() != k_new_method->name()) { 1099 // Methods are sorted by method name, so a mismatch means added 1100 // or deleted 1101 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) { 1102 method_was = added; 1103 } else { 1104 method_was = deleted; 1105 } 1106 } else if (k_old_method->signature() == k_new_method->signature()) { 1107 // Both the name and signature match 1108 method_was = matched; 1109 } else { 1110 // The name matches, but the signature doesn't, which means we have to 1111 // search forward through the new overloaded methods. 1112 int nj; // outside the loop for post-loop check 1113 for (nj = ni + 1; nj < n_new_methods; nj++) { 1114 Method* m = k_new_methods->at(nj); 1115 if (k_old_method->name() != m->name()) { 1116 // reached another method name so no more overloaded methods 1117 method_was = deleted; 1118 break; 1119 } 1120 if (k_old_method->signature() == m->signature()) { 1121 // found a match so swap the methods 1122 k_new_methods->at_put(ni, m); 1123 k_new_methods->at_put(nj, k_new_method); 1124 k_new_method = m; 1125 method_was = matched; 1126 break; 1127 } 1128 } 1129 1130 if (nj >= n_new_methods) { 1131 // reached the end without a match; so method was deleted 1132 method_was = deleted; 1133 } 1134 } 1135 } 1136 1137 switch (method_was) { 1138 case matched: 1139 // methods match, be sure modifiers do too 1140 old_flags = (jushort) k_old_method->access_flags().get_flags(); 1141 new_flags = (jushort) k_new_method->access_flags().get_flags(); 1142 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) { 1143 log_info(redefine, class, normalize) 1144 ("redefined class %s method %s modifiers error: modifiers changed from %d to %d", 1145 the_class->external_name(), k_old_method->name_and_sig_as_C_string(), old_flags, new_flags); 1146 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED; 1147 } 1148 { 1149 u2 new_num = k_new_method->method_idnum(); 1150 u2 old_num = k_old_method->method_idnum(); 1151 if (new_num != old_num) { 1152 Method* idnum_owner = scratch_class->method_with_idnum(old_num); 1153 if (idnum_owner != NULL) { 1154 // There is already a method assigned this idnum -- switch them 1155 // Take current and original idnum from the new_method 1156 idnum_owner->set_method_idnum(new_num); 1157 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum()); 1158 } 1159 // Take current and original idnum from the old_method 1160 k_new_method->set_method_idnum(old_num); 1161 k_new_method->set_orig_method_idnum(k_old_method->orig_method_idnum()); 1162 if (thread->has_pending_exception()) { 1163 return JVMTI_ERROR_OUT_OF_MEMORY; 1164 } 1165 } 1166 } 1167 log_trace(redefine, class, normalize) 1168 ("Method matched: new: %s [%d] == old: %s [%d]", 1169 k_new_method->name_and_sig_as_C_string(), ni, k_old_method->name_and_sig_as_C_string(), oi); 1170 // advance to next pair of methods 1171 ++oi; 1172 ++ni; 1173 break; 1174 case added: 1175 // method added, see if it is OK 1176 if (!can_add_or_delete(k_new_method)) { 1177 log_info(redefine, class, normalize) 1178 ("redefined class %s methods error: added method: %s [%d]", 1179 the_class->external_name(), k_new_method->name_and_sig_as_C_string(), ni); 1180 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED; 1181 } 1182 { 1183 u2 num = the_class->next_method_idnum(); 1184 if (num == ConstMethod::UNSET_IDNUM) { 1185 // cannot add any more methods 1186 log_info(redefine, class, normalize) 1187 ("redefined class %s methods error: can't create ID for new method %s [%d]", 1188 the_class->external_name(), k_new_method->name_and_sig_as_C_string(), ni); 1189 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED; 1190 } 1191 u2 new_num = k_new_method->method_idnum(); 1192 Method* idnum_owner = scratch_class->method_with_idnum(num); 1193 if (idnum_owner != NULL) { 1194 // There is already a method assigned this idnum -- switch them 1195 // Take current and original idnum from the new_method 1196 idnum_owner->set_method_idnum(new_num); 1197 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum()); 1198 } 1199 k_new_method->set_method_idnum(num); 1200 k_new_method->set_orig_method_idnum(num); 1201 if (thread->has_pending_exception()) { 1202 return JVMTI_ERROR_OUT_OF_MEMORY; 1203 } 1204 } 1205 log_trace(redefine, class, normalize) 1206 ("Method added: new: %s [%d]", k_new_method->name_and_sig_as_C_string(), ni); 1207 ++ni; // advance to next new method 1208 break; 1209 case deleted: 1210 // method deleted, see if it is OK 1211 if (!can_add_or_delete(k_old_method)) { 1212 log_info(redefine, class, normalize) 1213 ("redefined class %s methods error: deleted method %s [%d]", 1214 the_class->external_name(), k_old_method->name_and_sig_as_C_string(), oi); 1215 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED; 1216 } 1217 log_trace(redefine, class, normalize) 1218 ("Method deleted: old: %s [%d]", k_old_method->name_and_sig_as_C_string(), oi); 1219 ++oi; // advance to next old method 1220 break; 1221 default: 1222 ShouldNotReachHere(); 1223 } 1224 } 1225 1226 return JVMTI_ERROR_NONE; 1227 } 1228 1229 1230 // Find new constant pool index value for old constant pool index value 1231 // by searching the index map. Returns zero (0) if there is no mapped 1232 // value for the old constant pool index. 1233 int VM_RedefineClasses::find_new_index(int old_index) { 1234 if (_index_map_count == 0) { 1235 // map is empty so nothing can be found 1236 return 0; 1237 } 1238 1239 if (old_index < 1 || old_index >= _index_map_p->length()) { 1240 // The old_index is out of range so it is not mapped. This should 1241 // not happen in regular constant pool merging use, but it can 1242 // happen if a corrupt annotation is processed. 1243 return 0; 1244 } 1245 1246 int value = _index_map_p->at(old_index); 1247 if (value == -1) { 1248 // the old_index is not mapped 1249 return 0; 1250 } 1251 1252 return value; 1253 } // end find_new_index() 1254 1255 1256 // Find new bootstrap specifier index value for old bootstrap specifier index 1257 // value by searching the index map. Returns unused index (-1) if there is 1258 // no mapped value for the old bootstrap specifier index. 1259 int VM_RedefineClasses::find_new_operand_index(int old_index) { 1260 if (_operands_index_map_count == 0) { 1261 // map is empty so nothing can be found 1262 return -1; 1263 } 1264 1265 if (old_index == -1 || old_index >= _operands_index_map_p->length()) { 1266 // The old_index is out of range so it is not mapped. 1267 // This should not happen in regular constant pool merging use. 1268 return -1; 1269 } 1270 1271 int value = _operands_index_map_p->at(old_index); 1272 if (value == -1) { 1273 // the old_index is not mapped 1274 return -1; 1275 } 1276 1277 return value; 1278 } // end find_new_operand_index() 1279 1280 1281 // Returns true if the current mismatch is due to a resolved/unresolved 1282 // class pair. Otherwise, returns false. 1283 bool VM_RedefineClasses::is_unresolved_class_mismatch(const constantPoolHandle& cp1, 1284 int index1, const constantPoolHandle& cp2, int index2) { 1285 1286 jbyte t1 = cp1->tag_at(index1).value(); 1287 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) { 1288 return false; // wrong entry type; not our special case 1289 } 1290 1291 jbyte t2 = cp2->tag_at(index2).value(); 1292 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) { 1293 return false; // wrong entry type; not our special case 1294 } 1295 1296 if (t1 == t2) { 1297 return false; // not a mismatch; not our special case 1298 } 1299 1300 char *s1 = cp1->klass_name_at(index1)->as_C_string(); 1301 char *s2 = cp2->klass_name_at(index2)->as_C_string(); 1302 if (strcmp(s1, s2) != 0) { 1303 return false; // strings don't match; not our special case 1304 } 1305 1306 return true; // made it through the gauntlet; this is our special case 1307 } // end is_unresolved_class_mismatch() 1308 1309 1310 // The bug 6214132 caused the verification to fail. 1311 // 1. What's done in RedefineClasses() before verification: 1312 // a) A reference to the class being redefined (_the_class) and a 1313 // reference to new version of the class (_scratch_class) are 1314 // saved here for use during the bytecode verification phase of 1315 // RedefineClasses. 1316 // b) The _java_mirror field from _the_class is copied to the 1317 // _java_mirror field in _scratch_class. This means that a jclass 1318 // returned for _the_class or _scratch_class will refer to the 1319 // same Java mirror. The verifier will see the "one true mirror" 1320 // for the class being verified. 1321 // 2. See comments in JvmtiThreadState for what is done during verification. 1322 1323 class RedefineVerifyMark : public StackObj { 1324 private: 1325 JvmtiThreadState* _state; 1326 Klass* _scratch_class; 1327 OopHandle _scratch_mirror; 1328 1329 public: 1330 1331 RedefineVerifyMark(Klass* the_class, Klass* scratch_class, 1332 JvmtiThreadState* state) : _state(state), _scratch_class(scratch_class) 1333 { 1334 _state->set_class_versions_map(the_class, scratch_class); 1335 _scratch_mirror = the_class->java_mirror_handle(); // this is a copy that is swapped 1336 _scratch_class->swap_java_mirror_handle(_scratch_mirror); 1337 } 1338 1339 ~RedefineVerifyMark() { 1340 // Restore the scratch class's mirror, so when scratch_class is removed 1341 // the correct mirror pointing to it can be cleared. 1342 _scratch_class->swap_java_mirror_handle(_scratch_mirror); 1343 _state->clear_class_versions_map(); 1344 } 1345 }; 1346 1347 1348 jvmtiError VM_RedefineClasses::load_new_class_versions() { 1349 1350 // For consistency allocate memory using os::malloc wrapper. 1351 _scratch_classes = (InstanceKlass**) 1352 os::malloc(sizeof(InstanceKlass*) * _class_count, mtClass); 1353 if (_scratch_classes == NULL) { 1354 return JVMTI_ERROR_OUT_OF_MEMORY; 1355 } 1356 // Zero initialize the _scratch_classes array. 1357 for (int i = 0; i < _class_count; i++) { 1358 _scratch_classes[i] = NULL; 1359 } 1360 1361 JavaThread* current = JavaThread::current(); 1362 ResourceMark rm(current); 1363 1364 JvmtiThreadState *state = JvmtiThreadState::state_for(current); 1365 // state can only be NULL if the current thread is exiting which 1366 // should not happen since we're trying to do a RedefineClasses 1367 guarantee(state != NULL, "exiting thread calling load_new_class_versions"); 1368 for (int i = 0; i < _class_count; i++) { 1369 // Create HandleMark so that any handles created while loading new class 1370 // versions are deleted. Constant pools are deallocated while merging 1371 // constant pools 1372 HandleMark hm(current); 1373 InstanceKlass* the_class = get_ik(_class_defs[i].klass); 1374 1375 log_debug(redefine, class, load) 1376 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)", 1377 the_class->external_name(), _class_load_kind, os::available_memory() >> 10); 1378 1379 ClassFileStream st((u1*)_class_defs[i].class_bytes, 1380 _class_defs[i].class_byte_count, 1381 "__VM_RedefineClasses__", 1382 ClassFileStream::verify); 1383 1384 // Set redefined class handle in JvmtiThreadState class. 1385 // This redefined class is sent to agent event handler for class file 1386 // load hook event. 1387 state->set_class_being_redefined(the_class, _class_load_kind); 1388 1389 JavaThread* THREAD = current; // For exception macros. 1390 ExceptionMark em(THREAD); 1391 Handle protection_domain(THREAD, the_class->protection_domain()); 1392 ClassLoadInfo cl_info(protection_domain); 1393 // Parse and create a class from the bytes, but this class isn't added 1394 // to the dictionary, so do not call resolve_from_stream. 1395 InstanceKlass* scratch_class = KlassFactory::create_from_stream(&st, 1396 the_class->name(), 1397 the_class->class_loader_data(), 1398 cl_info, 1399 THREAD); 1400 1401 // Clear class_being_redefined just to be sure. 1402 state->clear_class_being_redefined(); 1403 1404 // TODO: if this is retransform, and nothing changed we can skip it 1405 1406 // Need to clean up allocated InstanceKlass if there's an error so assign 1407 // the result here. Caller deallocates all the scratch classes in case of 1408 // an error. 1409 _scratch_classes[i] = scratch_class; 1410 1411 if (HAS_PENDING_EXCEPTION) { 1412 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1413 log_info(redefine, class, load, exceptions)("create_from_stream exception: '%s'", ex_name->as_C_string()); 1414 CLEAR_PENDING_EXCEPTION; 1415 1416 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) { 1417 return JVMTI_ERROR_UNSUPPORTED_VERSION; 1418 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) { 1419 return JVMTI_ERROR_INVALID_CLASS_FORMAT; 1420 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) { 1421 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION; 1422 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) { 1423 // The message will be "XXX (wrong name: YYY)" 1424 return JVMTI_ERROR_NAMES_DONT_MATCH; 1425 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1426 return JVMTI_ERROR_OUT_OF_MEMORY; 1427 } else { // Just in case more exceptions can be thrown.. 1428 return JVMTI_ERROR_FAILS_VERIFICATION; 1429 } 1430 } 1431 1432 // Ensure class is linked before redefine 1433 if (!the_class->is_linked()) { 1434 the_class->link_class(THREAD); 1435 if (HAS_PENDING_EXCEPTION) { 1436 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1437 oop message = java_lang_Throwable::message(PENDING_EXCEPTION); 1438 if (message != NULL) { 1439 char* ex_msg = java_lang_String::as_utf8_string(message); 1440 log_info(redefine, class, load, exceptions)("link_class exception: '%s %s'", 1441 ex_name->as_C_string(), ex_msg); 1442 } else { 1443 log_info(redefine, class, load, exceptions)("link_class exception: '%s'", 1444 ex_name->as_C_string()); 1445 } 1446 CLEAR_PENDING_EXCEPTION; 1447 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1448 return JVMTI_ERROR_OUT_OF_MEMORY; 1449 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) { 1450 return JVMTI_ERROR_INVALID_CLASS; 1451 } else { 1452 return JVMTI_ERROR_INTERNAL; 1453 } 1454 } 1455 } 1456 1457 // Do the validity checks in compare_and_normalize_class_versions() 1458 // before verifying the byte codes. By doing these checks first, we 1459 // limit the number of functions that require redirection from 1460 // the_class to scratch_class. In particular, we don't have to 1461 // modify JNI GetSuperclass() and thus won't change its performance. 1462 jvmtiError res = compare_and_normalize_class_versions(the_class, 1463 scratch_class); 1464 if (res != JVMTI_ERROR_NONE) { 1465 return res; 1466 } 1467 1468 // verify what the caller passed us 1469 { 1470 // The bug 6214132 caused the verification to fail. 1471 // Information about the_class and scratch_class is temporarily 1472 // recorded into jvmtiThreadState. This data is used to redirect 1473 // the_class to scratch_class in the JVM_* functions called by the 1474 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed 1475 // description. 1476 RedefineVerifyMark rvm(the_class, scratch_class, state); 1477 Verifier::verify(scratch_class, true, THREAD); 1478 } 1479 1480 if (HAS_PENDING_EXCEPTION) { 1481 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1482 log_info(redefine, class, load, exceptions)("verify_byte_codes exception: '%s'", ex_name->as_C_string()); 1483 CLEAR_PENDING_EXCEPTION; 1484 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1485 return JVMTI_ERROR_OUT_OF_MEMORY; 1486 } else { 1487 // tell the caller the bytecodes are bad 1488 return JVMTI_ERROR_FAILS_VERIFICATION; 1489 } 1490 } 1491 1492 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD); 1493 if (HAS_PENDING_EXCEPTION) { 1494 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1495 log_info(redefine, class, load, exceptions)("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string()); 1496 CLEAR_PENDING_EXCEPTION; 1497 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1498 return JVMTI_ERROR_OUT_OF_MEMORY; 1499 } else { 1500 return JVMTI_ERROR_INTERNAL; 1501 } 1502 } 1503 1504 #ifdef ASSERT 1505 { 1506 // verify what we have done during constant pool merging 1507 { 1508 RedefineVerifyMark rvm(the_class, scratch_class, state); 1509 Verifier::verify(scratch_class, true, THREAD); 1510 } 1511 1512 if (HAS_PENDING_EXCEPTION) { 1513 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1514 log_info(redefine, class, load, exceptions) 1515 ("verify_byte_codes post merge-CP exception: '%s'", ex_name->as_C_string()); 1516 CLEAR_PENDING_EXCEPTION; 1517 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1518 return JVMTI_ERROR_OUT_OF_MEMORY; 1519 } else { 1520 // tell the caller that constant pool merging screwed up 1521 return JVMTI_ERROR_INTERNAL; 1522 } 1523 } 1524 } 1525 #endif // ASSERT 1526 1527 Rewriter::rewrite(scratch_class, THREAD); 1528 if (!HAS_PENDING_EXCEPTION) { 1529 scratch_class->link_methods(THREAD); 1530 } 1531 if (HAS_PENDING_EXCEPTION) { 1532 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1533 log_info(redefine, class, load, exceptions) 1534 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string()); 1535 CLEAR_PENDING_EXCEPTION; 1536 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1537 return JVMTI_ERROR_OUT_OF_MEMORY; 1538 } else { 1539 return JVMTI_ERROR_INTERNAL; 1540 } 1541 } 1542 1543 log_debug(redefine, class, load) 1544 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)", the_class->external_name(), os::available_memory() >> 10); 1545 } 1546 1547 return JVMTI_ERROR_NONE; 1548 } 1549 1550 1551 // Map old_index to new_index as needed. scratch_cp is only needed 1552 // for log calls. 1553 void VM_RedefineClasses::map_index(const constantPoolHandle& scratch_cp, 1554 int old_index, int new_index) { 1555 if (find_new_index(old_index) != 0) { 1556 // old_index is already mapped 1557 return; 1558 } 1559 1560 if (old_index == new_index) { 1561 // no mapping is needed 1562 return; 1563 } 1564 1565 _index_map_p->at_put(old_index, new_index); 1566 _index_map_count++; 1567 1568 log_trace(redefine, class, constantpool) 1569 ("mapped tag %d at index %d to %d", scratch_cp->tag_at(old_index).value(), old_index, new_index); 1570 } // end map_index() 1571 1572 1573 // Map old_index to new_index as needed. 1574 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) { 1575 if (find_new_operand_index(old_index) != -1) { 1576 // old_index is already mapped 1577 return; 1578 } 1579 1580 if (old_index == new_index) { 1581 // no mapping is needed 1582 return; 1583 } 1584 1585 _operands_index_map_p->at_put(old_index, new_index); 1586 _operands_index_map_count++; 1587 1588 log_trace(redefine, class, constantpool)("mapped bootstrap specifier at index %d to %d", old_index, new_index); 1589 } // end map_index() 1590 1591 1592 // Merge old_cp and scratch_cp and return the results of the merge via 1593 // merge_cp_p. The number of entries in *merge_cp_p is returned via 1594 // merge_cp_length_p. The entries in old_cp occupy the same locations 1595 // in *merge_cp_p. Also creates a map of indices from entries in 1596 // scratch_cp to the corresponding entry in *merge_cp_p. Index map 1597 // entries are only created for entries in scratch_cp that occupy a 1598 // different location in *merged_cp_p. 1599 bool VM_RedefineClasses::merge_constant_pools(const constantPoolHandle& old_cp, 1600 const constantPoolHandle& scratch_cp, constantPoolHandle *merge_cp_p, 1601 int *merge_cp_length_p, TRAPS) { 1602 1603 if (merge_cp_p == NULL) { 1604 assert(false, "caller must provide scratch constantPool"); 1605 return false; // robustness 1606 } 1607 if (merge_cp_length_p == NULL) { 1608 assert(false, "caller must provide scratch CP length"); 1609 return false; // robustness 1610 } 1611 // Worst case we need old_cp->length() + scratch_cp()->length(), 1612 // but the caller might be smart so make sure we have at least 1613 // the minimum. 1614 if ((*merge_cp_p)->length() < old_cp->length()) { 1615 assert(false, "merge area too small"); 1616 return false; // robustness 1617 } 1618 1619 log_info(redefine, class, constantpool)("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(), scratch_cp->length()); 1620 1621 { 1622 // Pass 0: 1623 // The old_cp is copied to *merge_cp_p; this means that any code 1624 // using old_cp does not have to change. This work looks like a 1625 // perfect fit for ConstantPool*::copy_cp_to(), but we need to 1626 // handle one special case: 1627 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass 1628 // This will make verification happy. 1629 1630 int old_i; // index into old_cp 1631 1632 // index zero (0) is not used in constantPools 1633 for (old_i = 1; old_i < old_cp->length(); old_i++) { 1634 // leave debugging crumb 1635 jbyte old_tag = old_cp->tag_at(old_i).value(); 1636 switch (old_tag) { 1637 case JVM_CONSTANT_Class: 1638 case JVM_CONSTANT_UnresolvedClass: 1639 // revert the copy to JVM_CONSTANT_UnresolvedClass 1640 // May be resolving while calling this so do the same for 1641 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition) 1642 (*merge_cp_p)->temp_unresolved_klass_at_put(old_i, 1643 old_cp->klass_name_index_at(old_i)); 1644 break; 1645 1646 case JVM_CONSTANT_Double: 1647 case JVM_CONSTANT_Long: 1648 // just copy the entry to *merge_cp_p, but double and long take 1649 // two constant pool entries 1650 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i); 1651 old_i++; 1652 break; 1653 1654 default: 1655 // just copy the entry to *merge_cp_p 1656 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i); 1657 break; 1658 } 1659 } // end for each old_cp entry 1660 1661 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_false); 1662 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_false); 1663 1664 // We don't need to sanity check that *merge_cp_length_p is within 1665 // *merge_cp_p bounds since we have the minimum on-entry check above. 1666 (*merge_cp_length_p) = old_i; 1667 } 1668 1669 // merge_cp_len should be the same as old_cp->length() at this point 1670 // so this trace message is really a "warm-and-breathing" message. 1671 log_debug(redefine, class, constantpool)("after pass 0: merge_cp_len=%d", *merge_cp_length_p); 1672 1673 int scratch_i; // index into scratch_cp 1674 { 1675 // Pass 1a: 1676 // Compare scratch_cp entries to the old_cp entries that we have 1677 // already copied to *merge_cp_p. In this pass, we are eliminating 1678 // exact duplicates (matching entry at same index) so we only 1679 // compare entries in the common indice range. 1680 int increment = 1; 1681 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length()); 1682 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) { 1683 switch (scratch_cp->tag_at(scratch_i).value()) { 1684 case JVM_CONSTANT_Double: 1685 case JVM_CONSTANT_Long: 1686 // double and long take two constant pool entries 1687 increment = 2; 1688 break; 1689 1690 default: 1691 increment = 1; 1692 break; 1693 } 1694 1695 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p, scratch_i); 1696 if (match) { 1697 // found a match at the same index so nothing more to do 1698 continue; 1699 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i, 1700 *merge_cp_p, scratch_i)) { 1701 // The mismatch in compare_entry_to() above is because of a 1702 // resolved versus unresolved class entry at the same index 1703 // with the same string value. Since Pass 0 reverted any 1704 // class entries to unresolved class entries in *merge_cp_p, 1705 // we go with the unresolved class entry. 1706 continue; 1707 } 1708 1709 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p); 1710 if (found_i != 0) { 1711 guarantee(found_i != scratch_i, 1712 "compare_entry_to() and find_matching_entry() do not agree"); 1713 1714 // Found a matching entry somewhere else in *merge_cp_p so 1715 // just need a mapping entry. 1716 map_index(scratch_cp, scratch_i, found_i); 1717 continue; 1718 } 1719 1720 // The find_matching_entry() call above could fail to find a match 1721 // due to a resolved versus unresolved class or string entry situation 1722 // like we solved above with the is_unresolved_*_mismatch() calls. 1723 // However, we would have to call is_unresolved_*_mismatch() over 1724 // all of *merge_cp_p (potentially) and that doesn't seem to be 1725 // worth the time. 1726 1727 // No match found so we have to append this entry and any unique 1728 // referenced entries to *merge_cp_p. 1729 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p); 1730 } 1731 } 1732 1733 log_debug(redefine, class, constantpool) 1734 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", 1735 *merge_cp_length_p, scratch_i, _index_map_count); 1736 1737 if (scratch_i < scratch_cp->length()) { 1738 // Pass 1b: 1739 // old_cp is smaller than scratch_cp so there are entries in 1740 // scratch_cp that we have not yet processed. We take care of 1741 // those now. 1742 int increment = 1; 1743 for (; scratch_i < scratch_cp->length(); scratch_i += increment) { 1744 switch (scratch_cp->tag_at(scratch_i).value()) { 1745 case JVM_CONSTANT_Double: 1746 case JVM_CONSTANT_Long: 1747 // double and long take two constant pool entries 1748 increment = 2; 1749 break; 1750 1751 default: 1752 increment = 1; 1753 break; 1754 } 1755 1756 int found_i = 1757 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p); 1758 if (found_i != 0) { 1759 // Found a matching entry somewhere else in *merge_cp_p so 1760 // just need a mapping entry. 1761 map_index(scratch_cp, scratch_i, found_i); 1762 continue; 1763 } 1764 1765 // No match found so we have to append this entry and any unique 1766 // referenced entries to *merge_cp_p. 1767 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p); 1768 } 1769 1770 log_debug(redefine, class, constantpool) 1771 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", 1772 *merge_cp_length_p, scratch_i, _index_map_count); 1773 } 1774 finalize_operands_merge(*merge_cp_p, CHECK_false); 1775 1776 return true; 1777 } // end merge_constant_pools() 1778 1779 1780 // Scoped object to clean up the constant pool(s) created for merging 1781 class MergeCPCleaner { 1782 ClassLoaderData* _loader_data; 1783 ConstantPool* _cp; 1784 ConstantPool* _scratch_cp; 1785 public: 1786 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) : 1787 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {} 1788 ~MergeCPCleaner() { 1789 _loader_data->add_to_deallocate_list(_cp); 1790 if (_scratch_cp != NULL) { 1791 _loader_data->add_to_deallocate_list(_scratch_cp); 1792 } 1793 } 1794 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; } 1795 }; 1796 1797 // Merge constant pools between the_class and scratch_class and 1798 // potentially rewrite bytecodes in scratch_class to use the merged 1799 // constant pool. 1800 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite( 1801 InstanceKlass* the_class, InstanceKlass* scratch_class, 1802 TRAPS) { 1803 // worst case merged constant pool length is old and new combined 1804 int merge_cp_length = the_class->constants()->length() 1805 + scratch_class->constants()->length(); 1806 1807 // Constant pools are not easily reused so we allocate a new one 1808 // each time. 1809 // merge_cp is created unsafe for concurrent GC processing. It 1810 // should be marked safe before discarding it. Even though 1811 // garbage, if it crosses a card boundary, it may be scanned 1812 // in order to find the start of the first complete object on the card. 1813 ClassLoaderData* loader_data = the_class->class_loader_data(); 1814 ConstantPool* merge_cp_oop = 1815 ConstantPool::allocate(loader_data, 1816 merge_cp_length, 1817 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1818 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop); 1819 1820 HandleMark hm(THREAD); // make sure handles are cleared before 1821 // MergeCPCleaner clears out merge_cp_oop 1822 constantPoolHandle merge_cp(THREAD, merge_cp_oop); 1823 1824 // Get constants() from the old class because it could have been rewritten 1825 // while we were at a safepoint allocating a new constant pool. 1826 constantPoolHandle old_cp(THREAD, the_class->constants()); 1827 constantPoolHandle scratch_cp(THREAD, scratch_class->constants()); 1828 1829 // If the length changed, the class was redefined out from under us. Return 1830 // an error. 1831 if (merge_cp_length != the_class->constants()->length() 1832 + scratch_class->constants()->length()) { 1833 return JVMTI_ERROR_INTERNAL; 1834 } 1835 1836 // Update the version number of the constant pools (may keep scratch_cp) 1837 merge_cp->increment_and_save_version(old_cp->version()); 1838 scratch_cp->increment_and_save_version(old_cp->version()); 1839 1840 ResourceMark rm(THREAD); 1841 _index_map_count = 0; 1842 _index_map_p = new intArray(scratch_cp->length(), scratch_cp->length(), -1); 1843 1844 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands()); 1845 _operands_index_map_count = 0; 1846 int operands_index_map_len = ConstantPool::operand_array_length(scratch_cp->operands()); 1847 _operands_index_map_p = new intArray(operands_index_map_len, operands_index_map_len, -1); 1848 1849 // reference to the cp holder is needed for copy_operands() 1850 merge_cp->set_pool_holder(scratch_class); 1851 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp, 1852 &merge_cp_length, THREAD); 1853 merge_cp->set_pool_holder(NULL); 1854 1855 if (!result) { 1856 // The merge can fail due to memory allocation failure or due 1857 // to robustness checks. 1858 return JVMTI_ERROR_INTERNAL; 1859 } 1860 1861 // Set dynamic constants attribute from the original CP. 1862 if (old_cp->has_dynamic_constant()) { 1863 scratch_cp->set_has_dynamic_constant(); 1864 } 1865 1866 log_info(redefine, class, constantpool)("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count); 1867 1868 if (_index_map_count == 0) { 1869 // there is nothing to map between the new and merged constant pools 1870 1871 // Copy attributes from scratch_cp to merge_cp 1872 merge_cp->copy_fields(scratch_cp()); 1873 1874 if (old_cp->length() == scratch_cp->length()) { 1875 // The old and new constant pools are the same length and the 1876 // index map is empty. This means that the three constant pools 1877 // are equivalent (but not the same). Unfortunately, the new 1878 // constant pool has not gone through link resolution nor have 1879 // the new class bytecodes gone through constant pool cache 1880 // rewriting so we can't use the old constant pool with the new 1881 // class. 1882 1883 // toss the merged constant pool at return 1884 } else if (old_cp->length() < scratch_cp->length()) { 1885 // The old constant pool has fewer entries than the new constant 1886 // pool and the index map is empty. This means the new constant 1887 // pool is a superset of the old constant pool. However, the old 1888 // class bytecodes have already gone through constant pool cache 1889 // rewriting so we can't use the new constant pool with the old 1890 // class. 1891 1892 // toss the merged constant pool at return 1893 } else { 1894 // The old constant pool has more entries than the new constant 1895 // pool and the index map is empty. This means that both the old 1896 // and merged constant pools are supersets of the new constant 1897 // pool. 1898 1899 // Replace the new constant pool with a shrunken copy of the 1900 // merged constant pool 1901 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, 1902 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1903 // The new constant pool replaces scratch_cp so have cleaner clean it up. 1904 // It can't be cleaned up while there are handles to it. 1905 cp_cleaner.add_scratch_cp(scratch_cp()); 1906 } 1907 } else { 1908 if (log_is_enabled(Trace, redefine, class, constantpool)) { 1909 // don't want to loop unless we are tracing 1910 int count = 0; 1911 for (int i = 1; i < _index_map_p->length(); i++) { 1912 int value = _index_map_p->at(i); 1913 1914 if (value != -1) { 1915 log_trace(redefine, class, constantpool)("index_map[%d]: old=%d new=%d", count, i, value); 1916 count++; 1917 } 1918 } 1919 } 1920 1921 // We have entries mapped between the new and merged constant pools 1922 // so we have to rewrite some constant pool references. 1923 if (!rewrite_cp_refs(scratch_class)) { 1924 return JVMTI_ERROR_INTERNAL; 1925 } 1926 1927 // Copy attributes from scratch_cp to merge_cp (should be done after rewrite_cp_refs()) 1928 merge_cp->copy_fields(scratch_cp()); 1929 1930 // Replace the new constant pool with a shrunken copy of the 1931 // merged constant pool so now the rewritten bytecodes have 1932 // valid references; the previous new constant pool will get 1933 // GCed. 1934 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, 1935 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1936 // The new constant pool replaces scratch_cp so have cleaner clean it up. 1937 // It can't be cleaned up while there are handles to it. 1938 cp_cleaner.add_scratch_cp(scratch_cp()); 1939 } 1940 1941 return JVMTI_ERROR_NONE; 1942 } // end merge_cp_and_rewrite() 1943 1944 1945 // Rewrite constant pool references in klass scratch_class. 1946 bool VM_RedefineClasses::rewrite_cp_refs(InstanceKlass* scratch_class) { 1947 1948 // rewrite constant pool references in the nest attributes: 1949 if (!rewrite_cp_refs_in_nest_attributes(scratch_class)) { 1950 // propagate failure back to caller 1951 return false; 1952 } 1953 1954 // rewrite constant pool references in the Record attribute: 1955 if (!rewrite_cp_refs_in_record_attribute(scratch_class)) { 1956 // propagate failure back to caller 1957 return false; 1958 } 1959 1960 // rewrite constant pool references in the PermittedSubclasses attribute: 1961 if (!rewrite_cp_refs_in_permitted_subclasses_attribute(scratch_class)) { 1962 // propagate failure back to caller 1963 return false; 1964 } 1965 1966 // rewrite constant pool references in the methods: 1967 if (!rewrite_cp_refs_in_methods(scratch_class)) { 1968 // propagate failure back to caller 1969 return false; 1970 } 1971 1972 // rewrite constant pool references in the class_annotations: 1973 if (!rewrite_cp_refs_in_class_annotations(scratch_class)) { 1974 // propagate failure back to caller 1975 return false; 1976 } 1977 1978 // rewrite constant pool references in the fields_annotations: 1979 if (!rewrite_cp_refs_in_fields_annotations(scratch_class)) { 1980 // propagate failure back to caller 1981 return false; 1982 } 1983 1984 // rewrite constant pool references in the methods_annotations: 1985 if (!rewrite_cp_refs_in_methods_annotations(scratch_class)) { 1986 // propagate failure back to caller 1987 return false; 1988 } 1989 1990 // rewrite constant pool references in the methods_parameter_annotations: 1991 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class)) { 1992 // propagate failure back to caller 1993 return false; 1994 } 1995 1996 // rewrite constant pool references in the methods_default_annotations: 1997 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class)) { 1998 // propagate failure back to caller 1999 return false; 2000 } 2001 2002 // rewrite constant pool references in the class_type_annotations: 2003 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class)) { 2004 // propagate failure back to caller 2005 return false; 2006 } 2007 2008 // rewrite constant pool references in the fields_type_annotations: 2009 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class)) { 2010 // propagate failure back to caller 2011 return false; 2012 } 2013 2014 // rewrite constant pool references in the methods_type_annotations: 2015 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class)) { 2016 // propagate failure back to caller 2017 return false; 2018 } 2019 2020 // There can be type annotations in the Code part of a method_info attribute. 2021 // These annotations are not accessible, even by reflection. 2022 // Currently they are not even parsed by the ClassFileParser. 2023 // If runtime access is added they will also need to be rewritten. 2024 2025 // rewrite source file name index: 2026 u2 source_file_name_idx = scratch_class->source_file_name_index(); 2027 if (source_file_name_idx != 0) { 2028 u2 new_source_file_name_idx = find_new_index(source_file_name_idx); 2029 if (new_source_file_name_idx != 0) { 2030 scratch_class->set_source_file_name_index(new_source_file_name_idx); 2031 } 2032 } 2033 2034 // rewrite class generic signature index: 2035 u2 generic_signature_index = scratch_class->generic_signature_index(); 2036 if (generic_signature_index != 0) { 2037 u2 new_generic_signature_index = find_new_index(generic_signature_index); 2038 if (new_generic_signature_index != 0) { 2039 scratch_class->set_generic_signature_index(new_generic_signature_index); 2040 } 2041 } 2042 2043 return true; 2044 } // end rewrite_cp_refs() 2045 2046 // Rewrite constant pool references in the NestHost and NestMembers attributes. 2047 bool VM_RedefineClasses::rewrite_cp_refs_in_nest_attributes( 2048 InstanceKlass* scratch_class) { 2049 2050 u2 cp_index = scratch_class->nest_host_index(); 2051 if (cp_index != 0) { 2052 scratch_class->set_nest_host_index(find_new_index(cp_index)); 2053 } 2054 Array<u2>* nest_members = scratch_class->nest_members(); 2055 for (int i = 0; i < nest_members->length(); i++) { 2056 u2 cp_index = nest_members->at(i); 2057 nest_members->at_put(i, find_new_index(cp_index)); 2058 } 2059 return true; 2060 } 2061 2062 // Rewrite constant pool references in the Record attribute. 2063 bool VM_RedefineClasses::rewrite_cp_refs_in_record_attribute(InstanceKlass* scratch_class) { 2064 Array<RecordComponent*>* components = scratch_class->record_components(); 2065 if (components != NULL) { 2066 for (int i = 0; i < components->length(); i++) { 2067 RecordComponent* component = components->at(i); 2068 u2 cp_index = component->name_index(); 2069 component->set_name_index(find_new_index(cp_index)); 2070 cp_index = component->descriptor_index(); 2071 component->set_descriptor_index(find_new_index(cp_index)); 2072 cp_index = component->generic_signature_index(); 2073 if (cp_index != 0) { 2074 component->set_generic_signature_index(find_new_index(cp_index)); 2075 } 2076 2077 AnnotationArray* annotations = component->annotations(); 2078 if (annotations != NULL && annotations->length() != 0) { 2079 int byte_i = 0; // byte index into annotations 2080 if (!rewrite_cp_refs_in_annotations_typeArray(annotations, byte_i)) { 2081 log_debug(redefine, class, annotation)("bad record_component_annotations at %d", i); 2082 // propagate failure back to caller 2083 return false; 2084 } 2085 } 2086 2087 AnnotationArray* type_annotations = component->type_annotations(); 2088 if (type_annotations != NULL && type_annotations->length() != 0) { 2089 int byte_i = 0; // byte index into annotations 2090 if (!rewrite_cp_refs_in_annotations_typeArray(type_annotations, byte_i)) { 2091 log_debug(redefine, class, annotation)("bad record_component_type_annotations at %d", i); 2092 // propagate failure back to caller 2093 return false; 2094 } 2095 } 2096 } 2097 } 2098 return true; 2099 } 2100 2101 // Rewrite constant pool references in the PermittedSubclasses attribute. 2102 bool VM_RedefineClasses::rewrite_cp_refs_in_permitted_subclasses_attribute( 2103 InstanceKlass* scratch_class) { 2104 2105 Array<u2>* permitted_subclasses = scratch_class->permitted_subclasses(); 2106 assert(permitted_subclasses != NULL, "unexpected null permitted_subclasses"); 2107 for (int i = 0; i < permitted_subclasses->length(); i++) { 2108 u2 cp_index = permitted_subclasses->at(i); 2109 permitted_subclasses->at_put(i, find_new_index(cp_index)); 2110 } 2111 return true; 2112 } 2113 2114 // Rewrite constant pool references in the methods. 2115 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(InstanceKlass* scratch_class) { 2116 2117 Array<Method*>* methods = scratch_class->methods(); 2118 2119 if (methods == NULL || methods->length() == 0) { 2120 // no methods so nothing to do 2121 return true; 2122 } 2123 2124 JavaThread* THREAD = JavaThread::current(); // For exception macros. 2125 ExceptionMark em(THREAD); 2126 2127 // rewrite constant pool references in the methods: 2128 for (int i = methods->length() - 1; i >= 0; i--) { 2129 methodHandle method(THREAD, methods->at(i)); 2130 methodHandle new_method; 2131 rewrite_cp_refs_in_method(method, &new_method, THREAD); 2132 if (!new_method.is_null()) { 2133 // the method has been replaced so save the new method version 2134 // even in the case of an exception. original method is on the 2135 // deallocation list. 2136 methods->at_put(i, new_method()); 2137 } 2138 if (HAS_PENDING_EXCEPTION) { 2139 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 2140 log_info(redefine, class, load, exceptions)("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string()); 2141 // Need to clear pending exception here as the super caller sets 2142 // the JVMTI_ERROR_INTERNAL if the returned value is false. 2143 CLEAR_PENDING_EXCEPTION; 2144 return false; 2145 } 2146 } 2147 2148 return true; 2149 } 2150 2151 2152 // Rewrite constant pool references in the specific method. This code 2153 // was adapted from Rewriter::rewrite_method(). 2154 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method, 2155 methodHandle *new_method_p, TRAPS) { 2156 2157 *new_method_p = methodHandle(); // default is no new method 2158 2159 // We cache a pointer to the bytecodes here in code_base. If GC 2160 // moves the Method*, then the bytecodes will also move which 2161 // will likely cause a crash. We create a NoSafepointVerifier 2162 // object to detect whether we pass a possible safepoint in this 2163 // code block. 2164 NoSafepointVerifier nsv; 2165 2166 // Bytecodes and their length 2167 address code_base = method->code_base(); 2168 int code_length = method->code_size(); 2169 2170 int bc_length; 2171 for (int bci = 0; bci < code_length; bci += bc_length) { 2172 address bcp = code_base + bci; 2173 Bytecodes::Code c = (Bytecodes::Code)(*bcp); 2174 2175 bc_length = Bytecodes::length_for(c); 2176 if (bc_length == 0) { 2177 // More complicated bytecodes report a length of zero so 2178 // we have to try again a slightly different way. 2179 bc_length = Bytecodes::length_at(method(), bcp); 2180 } 2181 2182 assert(bc_length != 0, "impossible bytecode length"); 2183 2184 switch (c) { 2185 case Bytecodes::_ldc: 2186 { 2187 int cp_index = *(bcp + 1); 2188 int new_index = find_new_index(cp_index); 2189 2190 if (StressLdcRewrite && new_index == 0) { 2191 // If we are stressing ldc -> ldc_w rewriting, then we 2192 // always need a new_index value. 2193 new_index = cp_index; 2194 } 2195 if (new_index != 0) { 2196 // the original index is mapped so we have more work to do 2197 if (!StressLdcRewrite && new_index <= max_jubyte) { 2198 // The new value can still use ldc instead of ldc_w 2199 // unless we are trying to stress ldc -> ldc_w rewriting 2200 log_trace(redefine, class, constantpool) 2201 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index); 2202 *(bcp + 1) = new_index; 2203 } else { 2204 log_trace(redefine, class, constantpool) 2205 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index); 2206 // the new value needs ldc_w instead of ldc 2207 u_char inst_buffer[4]; // max instruction size is 4 bytes 2208 bcp = (address)inst_buffer; 2209 // construct new instruction sequence 2210 *bcp = Bytecodes::_ldc_w; 2211 bcp++; 2212 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w. 2213 // See comment below for difference between put_Java_u2() 2214 // and put_native_u2(). 2215 Bytes::put_Java_u2(bcp, new_index); 2216 2217 Relocator rc(method, NULL /* no RelocatorListener needed */); 2218 methodHandle m; 2219 { 2220 PauseNoSafepointVerifier pnsv(&nsv); 2221 2222 // ldc is 2 bytes and ldc_w is 3 bytes 2223 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK); 2224 } 2225 2226 // return the new method so that the caller can update 2227 // the containing class 2228 *new_method_p = method = m; 2229 // switch our bytecode processing loop from the old method 2230 // to the new method 2231 code_base = method->code_base(); 2232 code_length = method->code_size(); 2233 bcp = code_base + bci; 2234 c = (Bytecodes::Code)(*bcp); 2235 bc_length = Bytecodes::length_for(c); 2236 assert(bc_length != 0, "sanity check"); 2237 } // end we need ldc_w instead of ldc 2238 } // end if there is a mapped index 2239 } break; 2240 2241 // these bytecodes have a two-byte constant pool index 2242 case Bytecodes::_anewarray : // fall through 2243 case Bytecodes::_checkcast : // fall through 2244 case Bytecodes::_getfield : // fall through 2245 case Bytecodes::_getstatic : // fall through 2246 case Bytecodes::_instanceof : // fall through 2247 case Bytecodes::_invokedynamic : // fall through 2248 case Bytecodes::_invokeinterface: // fall through 2249 case Bytecodes::_invokespecial : // fall through 2250 case Bytecodes::_invokestatic : // fall through 2251 case Bytecodes::_invokevirtual : // fall through 2252 case Bytecodes::_ldc_w : // fall through 2253 case Bytecodes::_ldc2_w : // fall through 2254 case Bytecodes::_multianewarray : // fall through 2255 case Bytecodes::_new : // fall through 2256 case Bytecodes::_putfield : // fall through 2257 case Bytecodes::_putstatic : 2258 { 2259 address p = bcp + 1; 2260 int cp_index = Bytes::get_Java_u2(p); 2261 int new_index = find_new_index(cp_index); 2262 if (new_index != 0) { 2263 // the original index is mapped so update w/ new value 2264 log_trace(redefine, class, constantpool) 2265 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),p2i(bcp), cp_index, new_index); 2266 // Rewriter::rewrite_method() uses put_native_u2() in this 2267 // situation because it is reusing the constant pool index 2268 // location for a native index into the ConstantPoolCache. 2269 // Since we are updating the constant pool index prior to 2270 // verification and ConstantPoolCache initialization, we 2271 // need to keep the new index in Java byte order. 2272 Bytes::put_Java_u2(p, new_index); 2273 } 2274 } break; 2275 default: 2276 break; 2277 } 2278 } // end for each bytecode 2279 } // end rewrite_cp_refs_in_method() 2280 2281 2282 // Rewrite constant pool references in the class_annotations field. 2283 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(InstanceKlass* scratch_class) { 2284 2285 AnnotationArray* class_annotations = scratch_class->class_annotations(); 2286 if (class_annotations == NULL || class_annotations->length() == 0) { 2287 // no class_annotations so nothing to do 2288 return true; 2289 } 2290 2291 log_debug(redefine, class, annotation)("class_annotations length=%d", class_annotations->length()); 2292 2293 int byte_i = 0; // byte index into class_annotations 2294 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i); 2295 } 2296 2297 2298 // Rewrite constant pool references in an annotations typeArray. This 2299 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute 2300 // that is described in section 4.8.15 of the 2nd-edition of the VM spec: 2301 // 2302 // annotations_typeArray { 2303 // u2 num_annotations; 2304 // annotation annotations[num_annotations]; 2305 // } 2306 // 2307 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray( 2308 AnnotationArray* annotations_typeArray, int &byte_i_ref) { 2309 2310 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2311 // not enough room for num_annotations field 2312 log_debug(redefine, class, annotation)("length() is too small for num_annotations field"); 2313 return false; 2314 } 2315 2316 u2 num_annotations = Bytes::get_Java_u2((address) 2317 annotations_typeArray->adr_at(byte_i_ref)); 2318 byte_i_ref += 2; 2319 2320 log_debug(redefine, class, annotation)("num_annotations=%d", num_annotations); 2321 2322 int calc_num_annotations = 0; 2323 for (; calc_num_annotations < num_annotations; calc_num_annotations++) { 2324 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, byte_i_ref)) { 2325 log_debug(redefine, class, annotation)("bad annotation_struct at %d", calc_num_annotations); 2326 // propagate failure back to caller 2327 return false; 2328 } 2329 } 2330 assert(num_annotations == calc_num_annotations, "sanity check"); 2331 2332 return true; 2333 } // end rewrite_cp_refs_in_annotations_typeArray() 2334 2335 2336 // Rewrite constant pool references in the annotation struct portion of 2337 // an annotations_typeArray. This "structure" is from section 4.8.15 of 2338 // the 2nd-edition of the VM spec: 2339 // 2340 // struct annotation { 2341 // u2 type_index; 2342 // u2 num_element_value_pairs; 2343 // { 2344 // u2 element_name_index; 2345 // element_value value; 2346 // } element_value_pairs[num_element_value_pairs]; 2347 // } 2348 // 2349 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct( 2350 AnnotationArray* annotations_typeArray, int &byte_i_ref) { 2351 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) { 2352 // not enough room for smallest annotation_struct 2353 log_debug(redefine, class, annotation)("length() is too small for annotation_struct"); 2354 return false; 2355 } 2356 2357 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray, 2358 byte_i_ref, "type_index"); 2359 2360 u2 num_element_value_pairs = Bytes::get_Java_u2((address) 2361 annotations_typeArray->adr_at(byte_i_ref)); 2362 byte_i_ref += 2; 2363 2364 log_debug(redefine, class, annotation) 2365 ("type_index=%d num_element_value_pairs=%d", type_index, num_element_value_pairs); 2366 2367 int calc_num_element_value_pairs = 0; 2368 for (; calc_num_element_value_pairs < num_element_value_pairs; 2369 calc_num_element_value_pairs++) { 2370 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2371 // not enough room for another element_name_index, let alone 2372 // the rest of another component 2373 log_debug(redefine, class, annotation)("length() is too small for element_name_index"); 2374 return false; 2375 } 2376 2377 u2 element_name_index = rewrite_cp_ref_in_annotation_data( 2378 annotations_typeArray, byte_i_ref, 2379 "element_name_index"); 2380 2381 log_debug(redefine, class, annotation)("element_name_index=%d", element_name_index); 2382 2383 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, byte_i_ref)) { 2384 log_debug(redefine, class, annotation)("bad element_value at %d", calc_num_element_value_pairs); 2385 // propagate failure back to caller 2386 return false; 2387 } 2388 } // end for each component 2389 assert(num_element_value_pairs == calc_num_element_value_pairs, 2390 "sanity check"); 2391 2392 return true; 2393 } // end rewrite_cp_refs_in_annotation_struct() 2394 2395 2396 // Rewrite a constant pool reference at the current position in 2397 // annotations_typeArray if needed. Returns the original constant 2398 // pool reference if a rewrite was not needed or the new constant 2399 // pool reference if a rewrite was needed. 2400 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data( 2401 AnnotationArray* annotations_typeArray, int &byte_i_ref, 2402 const char * trace_mesg) { 2403 2404 address cp_index_addr = (address) 2405 annotations_typeArray->adr_at(byte_i_ref); 2406 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr); 2407 u2 new_cp_index = find_new_index(old_cp_index); 2408 if (new_cp_index != 0) { 2409 log_debug(redefine, class, annotation)("mapped old %s=%d", trace_mesg, old_cp_index); 2410 Bytes::put_Java_u2(cp_index_addr, new_cp_index); 2411 old_cp_index = new_cp_index; 2412 } 2413 byte_i_ref += 2; 2414 return old_cp_index; 2415 } 2416 2417 2418 // Rewrite constant pool references in the element_value portion of an 2419 // annotations_typeArray. This "structure" is from section 4.8.15.1 of 2420 // the 2nd-edition of the VM spec: 2421 // 2422 // struct element_value { 2423 // u1 tag; 2424 // union { 2425 // u2 const_value_index; 2426 // { 2427 // u2 type_name_index; 2428 // u2 const_name_index; 2429 // } enum_const_value; 2430 // u2 class_info_index; 2431 // annotation annotation_value; 2432 // struct { 2433 // u2 num_values; 2434 // element_value values[num_values]; 2435 // } array_value; 2436 // } value; 2437 // } 2438 // 2439 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value( 2440 AnnotationArray* annotations_typeArray, int &byte_i_ref) { 2441 2442 if ((byte_i_ref + 1) > annotations_typeArray->length()) { 2443 // not enough room for a tag let alone the rest of an element_value 2444 log_debug(redefine, class, annotation)("length() is too small for a tag"); 2445 return false; 2446 } 2447 2448 u1 tag = annotations_typeArray->at(byte_i_ref); 2449 byte_i_ref++; 2450 log_debug(redefine, class, annotation)("tag='%c'", tag); 2451 2452 switch (tag) { 2453 // These BaseType tag values are from Table 4.2 in VM spec: 2454 case JVM_SIGNATURE_BYTE: 2455 case JVM_SIGNATURE_CHAR: 2456 case JVM_SIGNATURE_DOUBLE: 2457 case JVM_SIGNATURE_FLOAT: 2458 case JVM_SIGNATURE_INT: 2459 case JVM_SIGNATURE_LONG: 2460 case JVM_SIGNATURE_SHORT: 2461 case JVM_SIGNATURE_BOOLEAN: 2462 2463 // The remaining tag values are from Table 4.8 in the 2nd-edition of 2464 // the VM spec: 2465 case 's': 2466 { 2467 // For the above tag values (including the BaseType values), 2468 // value.const_value_index is right union field. 2469 2470 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2471 // not enough room for a const_value_index 2472 log_debug(redefine, class, annotation)("length() is too small for a const_value_index"); 2473 return false; 2474 } 2475 2476 u2 const_value_index = rewrite_cp_ref_in_annotation_data( 2477 annotations_typeArray, byte_i_ref, 2478 "const_value_index"); 2479 2480 log_debug(redefine, class, annotation)("const_value_index=%d", const_value_index); 2481 } break; 2482 2483 case 'e': 2484 { 2485 // for the above tag value, value.enum_const_value is right union field 2486 2487 if ((byte_i_ref + 4) > annotations_typeArray->length()) { 2488 // not enough room for a enum_const_value 2489 log_debug(redefine, class, annotation)("length() is too small for a enum_const_value"); 2490 return false; 2491 } 2492 2493 u2 type_name_index = rewrite_cp_ref_in_annotation_data( 2494 annotations_typeArray, byte_i_ref, 2495 "type_name_index"); 2496 2497 u2 const_name_index = rewrite_cp_ref_in_annotation_data( 2498 annotations_typeArray, byte_i_ref, 2499 "const_name_index"); 2500 2501 log_debug(redefine, class, annotation) 2502 ("type_name_index=%d const_name_index=%d", type_name_index, const_name_index); 2503 } break; 2504 2505 case 'c': 2506 { 2507 // for the above tag value, value.class_info_index is right union field 2508 2509 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2510 // not enough room for a class_info_index 2511 log_debug(redefine, class, annotation)("length() is too small for a class_info_index"); 2512 return false; 2513 } 2514 2515 u2 class_info_index = rewrite_cp_ref_in_annotation_data( 2516 annotations_typeArray, byte_i_ref, 2517 "class_info_index"); 2518 2519 log_debug(redefine, class, annotation)("class_info_index=%d", class_info_index); 2520 } break; 2521 2522 case '@': 2523 // For the above tag value, value.attr_value is the right union 2524 // field. This is a nested annotation. 2525 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, byte_i_ref)) { 2526 // propagate failure back to caller 2527 return false; 2528 } 2529 break; 2530 2531 case JVM_SIGNATURE_ARRAY: 2532 { 2533 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2534 // not enough room for a num_values field 2535 log_debug(redefine, class, annotation)("length() is too small for a num_values field"); 2536 return false; 2537 } 2538 2539 // For the above tag value, value.array_value is the right union 2540 // field. This is an array of nested element_value. 2541 u2 num_values = Bytes::get_Java_u2((address) 2542 annotations_typeArray->adr_at(byte_i_ref)); 2543 byte_i_ref += 2; 2544 log_debug(redefine, class, annotation)("num_values=%d", num_values); 2545 2546 int calc_num_values = 0; 2547 for (; calc_num_values < num_values; calc_num_values++) { 2548 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, byte_i_ref)) { 2549 log_debug(redefine, class, annotation)("bad nested element_value at %d", calc_num_values); 2550 // propagate failure back to caller 2551 return false; 2552 } 2553 } 2554 assert(num_values == calc_num_values, "sanity check"); 2555 } break; 2556 2557 default: 2558 log_debug(redefine, class, annotation)("bad tag=0x%x", tag); 2559 return false; 2560 } // end decode tag field 2561 2562 return true; 2563 } // end rewrite_cp_refs_in_element_value() 2564 2565 2566 // Rewrite constant pool references in a fields_annotations field. 2567 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations( 2568 InstanceKlass* scratch_class) { 2569 2570 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations(); 2571 2572 if (fields_annotations == NULL || fields_annotations->length() == 0) { 2573 // no fields_annotations so nothing to do 2574 return true; 2575 } 2576 2577 log_debug(redefine, class, annotation)("fields_annotations length=%d", fields_annotations->length()); 2578 2579 for (int i = 0; i < fields_annotations->length(); i++) { 2580 AnnotationArray* field_annotations = fields_annotations->at(i); 2581 if (field_annotations == NULL || field_annotations->length() == 0) { 2582 // this field does not have any annotations so skip it 2583 continue; 2584 } 2585 2586 int byte_i = 0; // byte index into field_annotations 2587 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i)) { 2588 log_debug(redefine, class, annotation)("bad field_annotations at %d", i); 2589 // propagate failure back to caller 2590 return false; 2591 } 2592 } 2593 2594 return true; 2595 } // end rewrite_cp_refs_in_fields_annotations() 2596 2597 2598 // Rewrite constant pool references in a methods_annotations field. 2599 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations( 2600 InstanceKlass* scratch_class) { 2601 2602 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2603 Method* m = scratch_class->methods()->at(i); 2604 AnnotationArray* method_annotations = m->constMethod()->method_annotations(); 2605 2606 if (method_annotations == NULL || method_annotations->length() == 0) { 2607 // this method does not have any annotations so skip it 2608 continue; 2609 } 2610 2611 int byte_i = 0; // byte index into method_annotations 2612 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i)) { 2613 log_debug(redefine, class, annotation)("bad method_annotations at %d", i); 2614 // propagate failure back to caller 2615 return false; 2616 } 2617 } 2618 2619 return true; 2620 } // end rewrite_cp_refs_in_methods_annotations() 2621 2622 2623 // Rewrite constant pool references in a methods_parameter_annotations 2624 // field. This "structure" is adapted from the 2625 // RuntimeVisibleParameterAnnotations_attribute described in section 2626 // 4.8.17 of the 2nd-edition of the VM spec: 2627 // 2628 // methods_parameter_annotations_typeArray { 2629 // u1 num_parameters; 2630 // { 2631 // u2 num_annotations; 2632 // annotation annotations[num_annotations]; 2633 // } parameter_annotations[num_parameters]; 2634 // } 2635 // 2636 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations( 2637 InstanceKlass* scratch_class) { 2638 2639 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2640 Method* m = scratch_class->methods()->at(i); 2641 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations(); 2642 if (method_parameter_annotations == NULL 2643 || method_parameter_annotations->length() == 0) { 2644 // this method does not have any parameter annotations so skip it 2645 continue; 2646 } 2647 2648 if (method_parameter_annotations->length() < 1) { 2649 // not enough room for a num_parameters field 2650 log_debug(redefine, class, annotation)("length() is too small for a num_parameters field at %d", i); 2651 return false; 2652 } 2653 2654 int byte_i = 0; // byte index into method_parameter_annotations 2655 2656 u1 num_parameters = method_parameter_annotations->at(byte_i); 2657 byte_i++; 2658 2659 log_debug(redefine, class, annotation)("num_parameters=%d", num_parameters); 2660 2661 int calc_num_parameters = 0; 2662 for (; calc_num_parameters < num_parameters; calc_num_parameters++) { 2663 if (!rewrite_cp_refs_in_annotations_typeArray(method_parameter_annotations, byte_i)) { 2664 log_debug(redefine, class, annotation)("bad method_parameter_annotations at %d", calc_num_parameters); 2665 // propagate failure back to caller 2666 return false; 2667 } 2668 } 2669 assert(num_parameters == calc_num_parameters, "sanity check"); 2670 } 2671 2672 return true; 2673 } // end rewrite_cp_refs_in_methods_parameter_annotations() 2674 2675 2676 // Rewrite constant pool references in a methods_default_annotations 2677 // field. This "structure" is adapted from the AnnotationDefault_attribute 2678 // that is described in section 4.8.19 of the 2nd-edition of the VM spec: 2679 // 2680 // methods_default_annotations_typeArray { 2681 // element_value default_value; 2682 // } 2683 // 2684 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations( 2685 InstanceKlass* scratch_class) { 2686 2687 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2688 Method* m = scratch_class->methods()->at(i); 2689 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations(); 2690 if (method_default_annotations == NULL 2691 || method_default_annotations->length() == 0) { 2692 // this method does not have any default annotations so skip it 2693 continue; 2694 } 2695 2696 int byte_i = 0; // byte index into method_default_annotations 2697 2698 if (!rewrite_cp_refs_in_element_value( 2699 method_default_annotations, byte_i)) { 2700 log_debug(redefine, class, annotation)("bad default element_value at %d", i); 2701 // propagate failure back to caller 2702 return false; 2703 } 2704 } 2705 2706 return true; 2707 } // end rewrite_cp_refs_in_methods_default_annotations() 2708 2709 2710 // Rewrite constant pool references in a class_type_annotations field. 2711 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations( 2712 InstanceKlass* scratch_class) { 2713 2714 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations(); 2715 if (class_type_annotations == NULL || class_type_annotations->length() == 0) { 2716 // no class_type_annotations so nothing to do 2717 return true; 2718 } 2719 2720 log_debug(redefine, class, annotation)("class_type_annotations length=%d", class_type_annotations->length()); 2721 2722 int byte_i = 0; // byte index into class_type_annotations 2723 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations, 2724 byte_i, "ClassFile"); 2725 } // end rewrite_cp_refs_in_class_type_annotations() 2726 2727 2728 // Rewrite constant pool references in a fields_type_annotations field. 2729 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations(InstanceKlass* scratch_class) { 2730 2731 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations(); 2732 if (fields_type_annotations == NULL || fields_type_annotations->length() == 0) { 2733 // no fields_type_annotations so nothing to do 2734 return true; 2735 } 2736 2737 log_debug(redefine, class, annotation)("fields_type_annotations length=%d", fields_type_annotations->length()); 2738 2739 for (int i = 0; i < fields_type_annotations->length(); i++) { 2740 AnnotationArray* field_type_annotations = fields_type_annotations->at(i); 2741 if (field_type_annotations == NULL || field_type_annotations->length() == 0) { 2742 // this field does not have any annotations so skip it 2743 continue; 2744 } 2745 2746 int byte_i = 0; // byte index into field_type_annotations 2747 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations, 2748 byte_i, "field_info")) { 2749 log_debug(redefine, class, annotation)("bad field_type_annotations at %d", i); 2750 // propagate failure back to caller 2751 return false; 2752 } 2753 } 2754 2755 return true; 2756 } // end rewrite_cp_refs_in_fields_type_annotations() 2757 2758 2759 // Rewrite constant pool references in a methods_type_annotations field. 2760 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations( 2761 InstanceKlass* scratch_class) { 2762 2763 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2764 Method* m = scratch_class->methods()->at(i); 2765 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations(); 2766 2767 if (method_type_annotations == NULL || method_type_annotations->length() == 0) { 2768 // this method does not have any annotations so skip it 2769 continue; 2770 } 2771 2772 log_debug(redefine, class, annotation)("methods type_annotations length=%d", method_type_annotations->length()); 2773 2774 int byte_i = 0; // byte index into method_type_annotations 2775 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations, 2776 byte_i, "method_info")) { 2777 log_debug(redefine, class, annotation)("bad method_type_annotations at %d", i); 2778 // propagate failure back to caller 2779 return false; 2780 } 2781 } 2782 2783 return true; 2784 } // end rewrite_cp_refs_in_methods_type_annotations() 2785 2786 2787 // Rewrite constant pool references in a type_annotations 2788 // field. This "structure" is adapted from the 2789 // RuntimeVisibleTypeAnnotations_attribute described in 2790 // section 4.7.20 of the Java SE 8 Edition of the VM spec: 2791 // 2792 // type_annotations_typeArray { 2793 // u2 num_annotations; 2794 // type_annotation annotations[num_annotations]; 2795 // } 2796 // 2797 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray( 2798 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2799 const char * location_mesg) { 2800 2801 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2802 // not enough room for num_annotations field 2803 log_debug(redefine, class, annotation)("length() is too small for num_annotations field"); 2804 return false; 2805 } 2806 2807 u2 num_annotations = Bytes::get_Java_u2((address) 2808 type_annotations_typeArray->adr_at(byte_i_ref)); 2809 byte_i_ref += 2; 2810 2811 log_debug(redefine, class, annotation)("num_type_annotations=%d", num_annotations); 2812 2813 int calc_num_annotations = 0; 2814 for (; calc_num_annotations < num_annotations; calc_num_annotations++) { 2815 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray, 2816 byte_i_ref, location_mesg)) { 2817 log_debug(redefine, class, annotation)("bad type_annotation_struct at %d", calc_num_annotations); 2818 // propagate failure back to caller 2819 return false; 2820 } 2821 } 2822 assert(num_annotations == calc_num_annotations, "sanity check"); 2823 2824 if (byte_i_ref != type_annotations_typeArray->length()) { 2825 log_debug(redefine, class, annotation) 2826 ("read wrong amount of bytes at end of processing type_annotations_typeArray (%d of %d bytes were read)", 2827 byte_i_ref, type_annotations_typeArray->length()); 2828 return false; 2829 } 2830 2831 return true; 2832 } // end rewrite_cp_refs_in_type_annotations_typeArray() 2833 2834 2835 // Rewrite constant pool references in a type_annotation 2836 // field. This "structure" is adapted from the 2837 // RuntimeVisibleTypeAnnotations_attribute described in 2838 // section 4.7.20 of the Java SE 8 Edition of the VM spec: 2839 // 2840 // type_annotation { 2841 // u1 target_type; 2842 // union { 2843 // type_parameter_target; 2844 // supertype_target; 2845 // type_parameter_bound_target; 2846 // empty_target; 2847 // method_formal_parameter_target; 2848 // throws_target; 2849 // localvar_target; 2850 // catch_target; 2851 // offset_target; 2852 // type_argument_target; 2853 // } target_info; 2854 // type_path target_path; 2855 // annotation anno; 2856 // } 2857 // 2858 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct( 2859 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2860 const char * location_mesg) { 2861 2862 if (!skip_type_annotation_target(type_annotations_typeArray, 2863 byte_i_ref, location_mesg)) { 2864 return false; 2865 } 2866 2867 if (!skip_type_annotation_type_path(type_annotations_typeArray, byte_i_ref)) { 2868 return false; 2869 } 2870 2871 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray, byte_i_ref)) { 2872 return false; 2873 } 2874 2875 return true; 2876 } // end rewrite_cp_refs_in_type_annotation_struct() 2877 2878 2879 // Read, verify and skip over the target_type and target_info part 2880 // so that rewriting can continue in the later parts of the struct. 2881 // 2882 // u1 target_type; 2883 // union { 2884 // type_parameter_target; 2885 // supertype_target; 2886 // type_parameter_bound_target; 2887 // empty_target; 2888 // method_formal_parameter_target; 2889 // throws_target; 2890 // localvar_target; 2891 // catch_target; 2892 // offset_target; 2893 // type_argument_target; 2894 // } target_info; 2895 // 2896 bool VM_RedefineClasses::skip_type_annotation_target( 2897 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2898 const char * location_mesg) { 2899 2900 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2901 // not enough room for a target_type let alone the rest of a type_annotation 2902 log_debug(redefine, class, annotation)("length() is too small for a target_type"); 2903 return false; 2904 } 2905 2906 u1 target_type = type_annotations_typeArray->at(byte_i_ref); 2907 byte_i_ref += 1; 2908 log_debug(redefine, class, annotation)("target_type=0x%.2x", target_type); 2909 log_debug(redefine, class, annotation)("location=%s", location_mesg); 2910 2911 // Skip over target_info 2912 switch (target_type) { 2913 case 0x00: 2914 // kind: type parameter declaration of generic class or interface 2915 // location: ClassFile 2916 case 0x01: 2917 // kind: type parameter declaration of generic method or constructor 2918 // location: method_info 2919 2920 { 2921 // struct: 2922 // type_parameter_target { 2923 // u1 type_parameter_index; 2924 // } 2925 // 2926 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2927 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_target"); 2928 return false; 2929 } 2930 2931 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2932 byte_i_ref += 1; 2933 2934 log_debug(redefine, class, annotation)("type_parameter_target: type_parameter_index=%d", type_parameter_index); 2935 } break; 2936 2937 case 0x10: 2938 // kind: type in extends clause of class or interface declaration 2939 // or in implements clause of interface declaration 2940 // location: ClassFile 2941 2942 { 2943 // struct: 2944 // supertype_target { 2945 // u2 supertype_index; 2946 // } 2947 // 2948 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2949 log_debug(redefine, class, annotation)("length() is too small for a supertype_target"); 2950 return false; 2951 } 2952 2953 u2 supertype_index = Bytes::get_Java_u2((address) 2954 type_annotations_typeArray->adr_at(byte_i_ref)); 2955 byte_i_ref += 2; 2956 2957 log_debug(redefine, class, annotation)("supertype_target: supertype_index=%d", supertype_index); 2958 } break; 2959 2960 case 0x11: 2961 // kind: type in bound of type parameter declaration of generic class or interface 2962 // location: ClassFile 2963 case 0x12: 2964 // kind: type in bound of type parameter declaration of generic method or constructor 2965 // location: method_info 2966 2967 { 2968 // struct: 2969 // type_parameter_bound_target { 2970 // u1 type_parameter_index; 2971 // u1 bound_index; 2972 // } 2973 // 2974 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2975 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_bound_target"); 2976 return false; 2977 } 2978 2979 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2980 byte_i_ref += 1; 2981 u1 bound_index = type_annotations_typeArray->at(byte_i_ref); 2982 byte_i_ref += 1; 2983 2984 log_debug(redefine, class, annotation) 2985 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d", type_parameter_index, bound_index); 2986 } break; 2987 2988 case 0x13: 2989 // kind: type in field declaration 2990 // location: field_info 2991 case 0x14: 2992 // kind: return type of method, or type of newly constructed object 2993 // location: method_info 2994 case 0x15: 2995 // kind: receiver type of method or constructor 2996 // location: method_info 2997 2998 { 2999 // struct: 3000 // empty_target { 3001 // } 3002 // 3003 log_debug(redefine, class, annotation)("empty_target"); 3004 } break; 3005 3006 case 0x16: 3007 // kind: type in formal parameter declaration of method, constructor, or lambda expression 3008 // location: method_info 3009 3010 { 3011 // struct: 3012 // formal_parameter_target { 3013 // u1 formal_parameter_index; 3014 // } 3015 // 3016 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 3017 log_debug(redefine, class, annotation)("length() is too small for a formal_parameter_target"); 3018 return false; 3019 } 3020 3021 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref); 3022 byte_i_ref += 1; 3023 3024 log_debug(redefine, class, annotation) 3025 ("formal_parameter_target: formal_parameter_index=%d", formal_parameter_index); 3026 } break; 3027 3028 case 0x17: 3029 // kind: type in throws clause of method or constructor 3030 // location: method_info 3031 3032 { 3033 // struct: 3034 // throws_target { 3035 // u2 throws_type_index 3036 // } 3037 // 3038 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 3039 log_debug(redefine, class, annotation)("length() is too small for a throws_target"); 3040 return false; 3041 } 3042 3043 u2 throws_type_index = Bytes::get_Java_u2((address) 3044 type_annotations_typeArray->adr_at(byte_i_ref)); 3045 byte_i_ref += 2; 3046 3047 log_debug(redefine, class, annotation)("throws_target: throws_type_index=%d", throws_type_index); 3048 } break; 3049 3050 case 0x40: 3051 // kind: type in local variable declaration 3052 // location: Code 3053 case 0x41: 3054 // kind: type in resource variable declaration 3055 // location: Code 3056 3057 { 3058 // struct: 3059 // localvar_target { 3060 // u2 table_length; 3061 // struct { 3062 // u2 start_pc; 3063 // u2 length; 3064 // u2 index; 3065 // } table[table_length]; 3066 // } 3067 // 3068 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 3069 // not enough room for a table_length let alone the rest of a localvar_target 3070 log_debug(redefine, class, annotation)("length() is too small for a localvar_target table_length"); 3071 return false; 3072 } 3073 3074 u2 table_length = Bytes::get_Java_u2((address) 3075 type_annotations_typeArray->adr_at(byte_i_ref)); 3076 byte_i_ref += 2; 3077 3078 log_debug(redefine, class, annotation)("localvar_target: table_length=%d", table_length); 3079 3080 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry 3081 int table_size = table_length * table_struct_size; 3082 3083 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) { 3084 // not enough room for a table 3085 log_debug(redefine, class, annotation)("length() is too small for a table array of length %d", table_length); 3086 return false; 3087 } 3088 3089 // Skip over table 3090 byte_i_ref += table_size; 3091 } break; 3092 3093 case 0x42: 3094 // kind: type in exception parameter declaration 3095 // location: Code 3096 3097 { 3098 // struct: 3099 // catch_target { 3100 // u2 exception_table_index; 3101 // } 3102 // 3103 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 3104 log_debug(redefine, class, annotation)("length() is too small for a catch_target"); 3105 return false; 3106 } 3107 3108 u2 exception_table_index = Bytes::get_Java_u2((address) 3109 type_annotations_typeArray->adr_at(byte_i_ref)); 3110 byte_i_ref += 2; 3111 3112 log_debug(redefine, class, annotation)("catch_target: exception_table_index=%d", exception_table_index); 3113 } break; 3114 3115 case 0x43: 3116 // kind: type in instanceof expression 3117 // location: Code 3118 case 0x44: 3119 // kind: type in new expression 3120 // location: Code 3121 case 0x45: 3122 // kind: type in method reference expression using ::new 3123 // location: Code 3124 case 0x46: 3125 // kind: type in method reference expression using ::Identifier 3126 // location: Code 3127 3128 { 3129 // struct: 3130 // offset_target { 3131 // u2 offset; 3132 // } 3133 // 3134 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 3135 log_debug(redefine, class, annotation)("length() is too small for a offset_target"); 3136 return false; 3137 } 3138 3139 u2 offset = Bytes::get_Java_u2((address) 3140 type_annotations_typeArray->adr_at(byte_i_ref)); 3141 byte_i_ref += 2; 3142 3143 log_debug(redefine, class, annotation)("offset_target: offset=%d", offset); 3144 } break; 3145 3146 case 0x47: 3147 // kind: type in cast expression 3148 // location: Code 3149 case 0x48: 3150 // kind: type argument for generic constructor in new expression or 3151 // explicit constructor invocation statement 3152 // location: Code 3153 case 0x49: 3154 // kind: type argument for generic method in method invocation expression 3155 // location: Code 3156 case 0x4A: 3157 // kind: type argument for generic constructor in method reference expression using ::new 3158 // location: Code 3159 case 0x4B: 3160 // kind: type argument for generic method in method reference expression using ::Identifier 3161 // location: Code 3162 3163 { 3164 // struct: 3165 // type_argument_target { 3166 // u2 offset; 3167 // u1 type_argument_index; 3168 // } 3169 // 3170 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) { 3171 log_debug(redefine, class, annotation)("length() is too small for a type_argument_target"); 3172 return false; 3173 } 3174 3175 u2 offset = Bytes::get_Java_u2((address) 3176 type_annotations_typeArray->adr_at(byte_i_ref)); 3177 byte_i_ref += 2; 3178 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref); 3179 byte_i_ref += 1; 3180 3181 log_debug(redefine, class, annotation) 3182 ("type_argument_target: offset=%d, type_argument_index=%d", offset, type_argument_index); 3183 } break; 3184 3185 default: 3186 log_debug(redefine, class, annotation)("unknown target_type"); 3187 #ifdef ASSERT 3188 ShouldNotReachHere(); 3189 #endif 3190 return false; 3191 } 3192 3193 return true; 3194 } // end skip_type_annotation_target() 3195 3196 3197 // Read, verify and skip over the type_path part so that rewriting 3198 // can continue in the later parts of the struct. 3199 // 3200 // type_path { 3201 // u1 path_length; 3202 // { 3203 // u1 type_path_kind; 3204 // u1 type_argument_index; 3205 // } path[path_length]; 3206 // } 3207 // 3208 bool VM_RedefineClasses::skip_type_annotation_type_path( 3209 AnnotationArray* type_annotations_typeArray, int &byte_i_ref) { 3210 3211 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 3212 // not enough room for a path_length let alone the rest of the type_path 3213 log_debug(redefine, class, annotation)("length() is too small for a type_path"); 3214 return false; 3215 } 3216 3217 u1 path_length = type_annotations_typeArray->at(byte_i_ref); 3218 byte_i_ref += 1; 3219 3220 log_debug(redefine, class, annotation)("type_path: path_length=%d", path_length); 3221 3222 int calc_path_length = 0; 3223 for (; calc_path_length < path_length; calc_path_length++) { 3224 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) { 3225 // not enough room for a path 3226 log_debug(redefine, class, annotation) 3227 ("length() is too small for path entry %d of %d", calc_path_length, path_length); 3228 return false; 3229 } 3230 3231 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref); 3232 byte_i_ref += 1; 3233 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref); 3234 byte_i_ref += 1; 3235 3236 log_debug(redefine, class, annotation) 3237 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d", 3238 calc_path_length, type_path_kind, type_argument_index); 3239 3240 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) { 3241 // not enough room for a path 3242 log_debug(redefine, class, annotation)("inconsistent type_path values"); 3243 return false; 3244 } 3245 } 3246 assert(path_length == calc_path_length, "sanity check"); 3247 3248 return true; 3249 } // end skip_type_annotation_type_path() 3250 3251 3252 // Rewrite constant pool references in the method's stackmap table. 3253 // These "structures" are adapted from the StackMapTable_attribute that 3254 // is described in section 4.8.4 of the 6.0 version of the VM spec 3255 // (dated 2005.10.26): 3256 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf 3257 // 3258 // stack_map { 3259 // u2 number_of_entries; 3260 // stack_map_frame entries[number_of_entries]; 3261 // } 3262 // 3263 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table( 3264 const methodHandle& method) { 3265 3266 if (!method->has_stackmap_table()) { 3267 return; 3268 } 3269 3270 AnnotationArray* stackmap_data = method->stackmap_data(); 3271 address stackmap_p = (address)stackmap_data->adr_at(0); 3272 address stackmap_end = stackmap_p + stackmap_data->length(); 3273 3274 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries"); 3275 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p); 3276 stackmap_p += 2; 3277 3278 log_debug(redefine, class, stackmap)("number_of_entries=%u", number_of_entries); 3279 3280 // walk through each stack_map_frame 3281 u2 calc_number_of_entries = 0; 3282 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) { 3283 // The stack_map_frame structure is a u1 frame_type followed by 3284 // 0 or more bytes of data: 3285 // 3286 // union stack_map_frame { 3287 // same_frame; 3288 // same_locals_1_stack_item_frame; 3289 // same_locals_1_stack_item_frame_extended; 3290 // chop_frame; 3291 // same_frame_extended; 3292 // append_frame; 3293 // full_frame; 3294 // } 3295 3296 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type"); 3297 u1 frame_type = *stackmap_p; 3298 stackmap_p++; 3299 3300 // same_frame { 3301 // u1 frame_type = SAME; /* 0-63 */ 3302 // } 3303 if (frame_type <= 63) { 3304 // nothing more to do for same_frame 3305 } 3306 3307 // same_locals_1_stack_item_frame { 3308 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */ 3309 // verification_type_info stack[1]; 3310 // } 3311 else if (frame_type >= 64 && frame_type <= 127) { 3312 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3313 calc_number_of_entries, frame_type); 3314 } 3315 3316 // reserved for future use 3317 else if (frame_type >= 128 && frame_type <= 246) { 3318 // nothing more to do for reserved frame_types 3319 } 3320 3321 // same_locals_1_stack_item_frame_extended { 3322 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */ 3323 // u2 offset_delta; 3324 // verification_type_info stack[1]; 3325 // } 3326 else if (frame_type == 247) { 3327 stackmap_p += 2; 3328 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3329 calc_number_of_entries, frame_type); 3330 } 3331 3332 // chop_frame { 3333 // u1 frame_type = CHOP; /* 248-250 */ 3334 // u2 offset_delta; 3335 // } 3336 else if (frame_type >= 248 && frame_type <= 250) { 3337 stackmap_p += 2; 3338 } 3339 3340 // same_frame_extended { 3341 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/ 3342 // u2 offset_delta; 3343 // } 3344 else if (frame_type == 251) { 3345 stackmap_p += 2; 3346 } 3347 3348 // append_frame { 3349 // u1 frame_type = APPEND; /* 252-254 */ 3350 // u2 offset_delta; 3351 // verification_type_info locals[frame_type - 251]; 3352 // } 3353 else if (frame_type >= 252 && frame_type <= 254) { 3354 assert(stackmap_p + 2 <= stackmap_end, 3355 "no room for offset_delta"); 3356 stackmap_p += 2; 3357 u1 len = frame_type - 251; 3358 for (u1 i = 0; i < len; i++) { 3359 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3360 calc_number_of_entries, frame_type); 3361 } 3362 } 3363 3364 // full_frame { 3365 // u1 frame_type = FULL_FRAME; /* 255 */ 3366 // u2 offset_delta; 3367 // u2 number_of_locals; 3368 // verification_type_info locals[number_of_locals]; 3369 // u2 number_of_stack_items; 3370 // verification_type_info stack[number_of_stack_items]; 3371 // } 3372 else if (frame_type == 255) { 3373 assert(stackmap_p + 2 + 2 <= stackmap_end, 3374 "no room for smallest full_frame"); 3375 stackmap_p += 2; 3376 3377 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p); 3378 stackmap_p += 2; 3379 3380 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) { 3381 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3382 calc_number_of_entries, frame_type); 3383 } 3384 3385 // Use the largest size for the number_of_stack_items, but only get 3386 // the right number of bytes. 3387 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p); 3388 stackmap_p += 2; 3389 3390 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) { 3391 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3392 calc_number_of_entries, frame_type); 3393 } 3394 } 3395 } // end while there is a stack_map_frame 3396 assert(number_of_entries == calc_number_of_entries, "sanity check"); 3397 } // end rewrite_cp_refs_in_stack_map_table() 3398 3399 3400 // Rewrite constant pool references in the verification type info 3401 // portion of the method's stackmap table. These "structures" are 3402 // adapted from the StackMapTable_attribute that is described in 3403 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26): 3404 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf 3405 // 3406 // The verification_type_info structure is a u1 tag followed by 0 or 3407 // more bytes of data: 3408 // 3409 // union verification_type_info { 3410 // Top_variable_info; 3411 // Integer_variable_info; 3412 // Float_variable_info; 3413 // Long_variable_info; 3414 // Double_variable_info; 3415 // Null_variable_info; 3416 // UninitializedThis_variable_info; 3417 // Object_variable_info; 3418 // Uninitialized_variable_info; 3419 // } 3420 // 3421 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info( 3422 address& stackmap_p_ref, address stackmap_end, u2 frame_i, 3423 u1 frame_type) { 3424 3425 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag"); 3426 u1 tag = *stackmap_p_ref; 3427 stackmap_p_ref++; 3428 3429 switch (tag) { 3430 // Top_variable_info { 3431 // u1 tag = ITEM_Top; /* 0 */ 3432 // } 3433 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top 3434 case 0: // fall through 3435 3436 // Integer_variable_info { 3437 // u1 tag = ITEM_Integer; /* 1 */ 3438 // } 3439 case ITEM_Integer: // fall through 3440 3441 // Float_variable_info { 3442 // u1 tag = ITEM_Float; /* 2 */ 3443 // } 3444 case ITEM_Float: // fall through 3445 3446 // Double_variable_info { 3447 // u1 tag = ITEM_Double; /* 3 */ 3448 // } 3449 case ITEM_Double: // fall through 3450 3451 // Long_variable_info { 3452 // u1 tag = ITEM_Long; /* 4 */ 3453 // } 3454 case ITEM_Long: // fall through 3455 3456 // Null_variable_info { 3457 // u1 tag = ITEM_Null; /* 5 */ 3458 // } 3459 case ITEM_Null: // fall through 3460 3461 // UninitializedThis_variable_info { 3462 // u1 tag = ITEM_UninitializedThis; /* 6 */ 3463 // } 3464 case ITEM_UninitializedThis: 3465 // nothing more to do for the above tag types 3466 break; 3467 3468 // Object_variable_info { 3469 // u1 tag = ITEM_Object; /* 7 */ 3470 // u2 cpool_index; 3471 // } 3472 case ITEM_Object: 3473 { 3474 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index"); 3475 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref); 3476 u2 new_cp_index = find_new_index(cpool_index); 3477 if (new_cp_index != 0) { 3478 log_debug(redefine, class, stackmap)("mapped old cpool_index=%d", cpool_index); 3479 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index); 3480 cpool_index = new_cp_index; 3481 } 3482 stackmap_p_ref += 2; 3483 3484 log_debug(redefine, class, stackmap) 3485 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i, frame_type, cpool_index); 3486 } break; 3487 3488 // Uninitialized_variable_info { 3489 // u1 tag = ITEM_Uninitialized; /* 8 */ 3490 // u2 offset; 3491 // } 3492 case ITEM_Uninitialized: 3493 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset"); 3494 stackmap_p_ref += 2; 3495 break; 3496 3497 default: 3498 log_debug(redefine, class, stackmap)("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag); 3499 ShouldNotReachHere(); 3500 break; 3501 } // end switch (tag) 3502 } // end rewrite_cp_refs_in_verification_type_info() 3503 3504 3505 // Change the constant pool associated with klass scratch_class to scratch_cp. 3506 // scratch_cp_length elements are copied from scratch_cp to a smaller constant pool 3507 // and the smaller constant pool is associated with scratch_class. 3508 void VM_RedefineClasses::set_new_constant_pool( 3509 ClassLoaderData* loader_data, 3510 InstanceKlass* scratch_class, constantPoolHandle scratch_cp, 3511 int scratch_cp_length, TRAPS) { 3512 assert(scratch_cp->length() >= scratch_cp_length, "sanity check"); 3513 3514 // scratch_cp is a merged constant pool and has enough space for a 3515 // worst case merge situation. We want to associate the minimum 3516 // sized constant pool with the klass to save space. 3517 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK); 3518 constantPoolHandle smaller_cp(THREAD, cp); 3519 3520 // preserve version() value in the smaller copy 3521 int version = scratch_cp->version(); 3522 assert(version != 0, "sanity check"); 3523 smaller_cp->set_version(version); 3524 3525 // attach klass to new constant pool 3526 // reference to the cp holder is needed for copy_operands() 3527 smaller_cp->set_pool_holder(scratch_class); 3528 3529 smaller_cp->copy_fields(scratch_cp()); 3530 3531 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD); 3532 if (HAS_PENDING_EXCEPTION) { 3533 // Exception is handled in the caller 3534 loader_data->add_to_deallocate_list(smaller_cp()); 3535 return; 3536 } 3537 scratch_cp = smaller_cp; 3538 3539 // attach new constant pool to klass 3540 scratch_class->set_constants(scratch_cp()); 3541 scratch_cp->initialize_unresolved_klasses(loader_data, CHECK); 3542 3543 int i; // for portability 3544 3545 // update each field in klass to use new constant pool indices as needed 3546 for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) { 3547 jshort cur_index = fs.name_index(); 3548 jshort new_index = find_new_index(cur_index); 3549 if (new_index != 0) { 3550 log_trace(redefine, class, constantpool)("field-name_index change: %d to %d", cur_index, new_index); 3551 fs.set_name_index(new_index); 3552 } 3553 cur_index = fs.signature_index(); 3554 new_index = find_new_index(cur_index); 3555 if (new_index != 0) { 3556 log_trace(redefine, class, constantpool)("field-signature_index change: %d to %d", cur_index, new_index); 3557 fs.set_signature_index(new_index); 3558 } 3559 cur_index = fs.initval_index(); 3560 new_index = find_new_index(cur_index); 3561 if (new_index != 0) { 3562 log_trace(redefine, class, constantpool)("field-initval_index change: %d to %d", cur_index, new_index); 3563 fs.set_initval_index(new_index); 3564 } 3565 cur_index = fs.generic_signature_index(); 3566 new_index = find_new_index(cur_index); 3567 if (new_index != 0) { 3568 log_trace(redefine, class, constantpool)("field-generic_signature change: %d to %d", cur_index, new_index); 3569 fs.set_generic_signature_index(new_index); 3570 } 3571 } // end for each field 3572 3573 // Update constant pool indices in the inner classes info to use 3574 // new constant indices as needed. The inner classes info is a 3575 // quadruple: 3576 // (inner_class_info, outer_class_info, inner_name, inner_access_flags) 3577 InnerClassesIterator iter(scratch_class); 3578 for (; !iter.done(); iter.next()) { 3579 int cur_index = iter.inner_class_info_index(); 3580 if (cur_index == 0) { 3581 continue; // JVM spec. allows null inner class refs so skip it 3582 } 3583 int new_index = find_new_index(cur_index); 3584 if (new_index != 0) { 3585 log_trace(redefine, class, constantpool)("inner_class_info change: %d to %d", cur_index, new_index); 3586 iter.set_inner_class_info_index(new_index); 3587 } 3588 cur_index = iter.outer_class_info_index(); 3589 new_index = find_new_index(cur_index); 3590 if (new_index != 0) { 3591 log_trace(redefine, class, constantpool)("outer_class_info change: %d to %d", cur_index, new_index); 3592 iter.set_outer_class_info_index(new_index); 3593 } 3594 cur_index = iter.inner_name_index(); 3595 new_index = find_new_index(cur_index); 3596 if (new_index != 0) { 3597 log_trace(redefine, class, constantpool)("inner_name change: %d to %d", cur_index, new_index); 3598 iter.set_inner_name_index(new_index); 3599 } 3600 } // end for each inner class 3601 3602 // Attach each method in klass to the new constant pool and update 3603 // to use new constant pool indices as needed: 3604 Array<Method*>* methods = scratch_class->methods(); 3605 for (i = methods->length() - 1; i >= 0; i--) { 3606 methodHandle method(THREAD, methods->at(i)); 3607 method->set_constants(scratch_cp()); 3608 3609 int new_index = find_new_index(method->name_index()); 3610 if (new_index != 0) { 3611 log_trace(redefine, class, constantpool) 3612 ("method-name_index change: %d to %d", method->name_index(), new_index); 3613 method->set_name_index(new_index); 3614 } 3615 new_index = find_new_index(method->signature_index()); 3616 if (new_index != 0) { 3617 log_trace(redefine, class, constantpool) 3618 ("method-signature_index change: %d to %d", method->signature_index(), new_index); 3619 method->set_signature_index(new_index); 3620 } 3621 new_index = find_new_index(method->generic_signature_index()); 3622 if (new_index != 0) { 3623 log_trace(redefine, class, constantpool) 3624 ("method-generic_signature_index change: %d to %d", method->generic_signature_index(), new_index); 3625 method->set_generic_signature_index(new_index); 3626 } 3627 3628 // Update constant pool indices in the method's checked exception 3629 // table to use new constant indices as needed. 3630 int cext_length = method->checked_exceptions_length(); 3631 if (cext_length > 0) { 3632 CheckedExceptionElement * cext_table = 3633 method->checked_exceptions_start(); 3634 for (int j = 0; j < cext_length; j++) { 3635 int cur_index = cext_table[j].class_cp_index; 3636 int new_index = find_new_index(cur_index); 3637 if (new_index != 0) { 3638 log_trace(redefine, class, constantpool)("cext-class_cp_index change: %d to %d", cur_index, new_index); 3639 cext_table[j].class_cp_index = (u2)new_index; 3640 } 3641 } // end for each checked exception table entry 3642 } // end if there are checked exception table entries 3643 3644 // Update each catch type index in the method's exception table 3645 // to use new constant pool indices as needed. The exception table 3646 // holds quadruple entries of the form: 3647 // (beg_bci, end_bci, handler_bci, klass_index) 3648 3649 ExceptionTable ex_table(method()); 3650 int ext_length = ex_table.length(); 3651 3652 for (int j = 0; j < ext_length; j ++) { 3653 int cur_index = ex_table.catch_type_index(j); 3654 int new_index = find_new_index(cur_index); 3655 if (new_index != 0) { 3656 log_trace(redefine, class, constantpool)("ext-klass_index change: %d to %d", cur_index, new_index); 3657 ex_table.set_catch_type_index(j, new_index); 3658 } 3659 } // end for each exception table entry 3660 3661 // Update constant pool indices in the method's local variable 3662 // table to use new constant indices as needed. The local variable 3663 // table hold sextuple entries of the form: 3664 // (start_pc, length, name_index, descriptor_index, signature_index, slot) 3665 int lvt_length = method->localvariable_table_length(); 3666 if (lvt_length > 0) { 3667 LocalVariableTableElement * lv_table = 3668 method->localvariable_table_start(); 3669 for (int j = 0; j < lvt_length; j++) { 3670 int cur_index = lv_table[j].name_cp_index; 3671 int new_index = find_new_index(cur_index); 3672 if (new_index != 0) { 3673 log_trace(redefine, class, constantpool)("lvt-name_cp_index change: %d to %d", cur_index, new_index); 3674 lv_table[j].name_cp_index = (u2)new_index; 3675 } 3676 cur_index = lv_table[j].descriptor_cp_index; 3677 new_index = find_new_index(cur_index); 3678 if (new_index != 0) { 3679 log_trace(redefine, class, constantpool)("lvt-descriptor_cp_index change: %d to %d", cur_index, new_index); 3680 lv_table[j].descriptor_cp_index = (u2)new_index; 3681 } 3682 cur_index = lv_table[j].signature_cp_index; 3683 new_index = find_new_index(cur_index); 3684 if (new_index != 0) { 3685 log_trace(redefine, class, constantpool)("lvt-signature_cp_index change: %d to %d", cur_index, new_index); 3686 lv_table[j].signature_cp_index = (u2)new_index; 3687 } 3688 } // end for each local variable table entry 3689 } // end if there are local variable table entries 3690 3691 // Update constant pool indices in the method's method_parameters. 3692 int mp_length = method->method_parameters_length(); 3693 if (mp_length > 0) { 3694 MethodParametersElement* elem = method->method_parameters_start(); 3695 for (int j = 0; j < mp_length; j++) { 3696 const int cp_index = elem[j].name_cp_index; 3697 const int new_cp_index = find_new_index(cp_index); 3698 if (new_cp_index != 0) { 3699 elem[j].name_cp_index = (u2)new_cp_index; 3700 } 3701 } 3702 } 3703 3704 rewrite_cp_refs_in_stack_map_table(method); 3705 } // end for each method 3706 } // end set_new_constant_pool() 3707 3708 3709 // Unevolving classes may point to methods of the_class directly 3710 // from their constant pool caches, itables, and/or vtables. We 3711 // use the ClassLoaderDataGraph::classes_do() facility and this helper 3712 // to fix up these pointers. MethodData also points to old methods and 3713 // must be cleaned. 3714 3715 // Adjust cpools and vtables closure 3716 void VM_RedefineClasses::AdjustAndCleanMetadata::do_klass(Klass* k) { 3717 3718 // This is a very busy routine. We don't want too much tracing 3719 // printed out. 3720 bool trace_name_printed = false; 3721 3722 // If the class being redefined is java.lang.Object, we need to fix all 3723 // array class vtables also. The _has_redefined_Object flag is global. 3724 // Once the java.lang.Object has been redefined (by the current or one 3725 // of the previous VM_RedefineClasses operations) we have to always 3726 // adjust method entries for array classes. 3727 if (k->is_array_klass() && _has_redefined_Object) { 3728 k->vtable().adjust_method_entries(&trace_name_printed); 3729 3730 } else if (k->is_instance_klass()) { 3731 HandleMark hm(_thread); 3732 InstanceKlass *ik = InstanceKlass::cast(k); 3733 3734 // Clean MethodData of this class's methods so they don't refer to 3735 // old methods that are no longer running. 3736 Array<Method*>* methods = ik->methods(); 3737 int num_methods = methods->length(); 3738 for (int index = 0; index < num_methods; ++index) { 3739 if (methods->at(index)->method_data() != NULL) { 3740 methods->at(index)->method_data()->clean_weak_method_links(); 3741 } 3742 } 3743 3744 // Adjust all vtables, default methods and itables, to clean out old methods. 3745 ResourceMark rm(_thread); 3746 if (ik->vtable_length() > 0) { 3747 ik->vtable().adjust_method_entries(&trace_name_printed); 3748 ik->adjust_default_methods(&trace_name_printed); 3749 } 3750 3751 if (ik->itable_length() > 0) { 3752 ik->itable().adjust_method_entries(&trace_name_printed); 3753 } 3754 3755 // The constant pools in other classes (other_cp) can refer to 3756 // old methods. We have to update method information in 3757 // other_cp's cache. If other_cp has a previous version, then we 3758 // have to repeat the process for each previous version. The 3759 // constant pool cache holds the Method*s for non-virtual 3760 // methods and for virtual, final methods. 3761 // 3762 // Special case: if the current class is being redefined by the current 3763 // VM_RedefineClasses operation, then new_cp has already been attached 3764 // to the_class and old_cp has already been added as a previous version. 3765 // The new_cp doesn't have any cached references to old methods so it 3766 // doesn't need to be updated and we could optimize by skipping it. 3767 // However, the current class can be marked as being redefined by another 3768 // VM_RedefineClasses operation which has already executed its doit_prologue 3769 // and needs cpcache method entries adjusted. For simplicity, the cpcache 3770 // update is done unconditionally. It should result in doing nothing for 3771 // classes being redefined by the current VM_RedefineClasses operation. 3772 // Method entries in the previous version(s) are adjusted as well. 3773 ConstantPoolCache* cp_cache; 3774 3775 // this klass' constant pool cache may need adjustment 3776 ConstantPool* other_cp = ik->constants(); 3777 cp_cache = other_cp->cache(); 3778 if (cp_cache != NULL) { 3779 cp_cache->adjust_method_entries(&trace_name_printed); 3780 } 3781 3782 // the previous versions' constant pool caches may need adjustment 3783 for (InstanceKlass* pv_node = ik->previous_versions(); 3784 pv_node != NULL; 3785 pv_node = pv_node->previous_versions()) { 3786 cp_cache = pv_node->constants()->cache(); 3787 if (cp_cache != NULL) { 3788 cp_cache->adjust_method_entries(&trace_name_printed); 3789 } 3790 } 3791 } 3792 } 3793 3794 void VM_RedefineClasses::update_jmethod_ids() { 3795 for (int j = 0; j < _matching_methods_length; ++j) { 3796 Method* old_method = _matching_old_methods[j]; 3797 jmethodID jmid = old_method->find_jmethod_id_or_null(); 3798 if (jmid != NULL) { 3799 // There is a jmethodID, change it to point to the new method 3800 Method* new_method = _matching_new_methods[j]; 3801 Method::change_method_associated_with_jmethod_id(jmid, new_method); 3802 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j], 3803 "should be replaced"); 3804 } 3805 } 3806 } 3807 3808 int VM_RedefineClasses::check_methods_and_mark_as_obsolete() { 3809 int emcp_method_count = 0; 3810 int obsolete_count = 0; 3811 int old_index = 0; 3812 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) { 3813 Method* old_method = _matching_old_methods[j]; 3814 Method* new_method = _matching_new_methods[j]; 3815 Method* old_array_method; 3816 3817 // Maintain an old_index into the _old_methods array by skipping 3818 // deleted methods 3819 while ((old_array_method = _old_methods->at(old_index)) != old_method) { 3820 ++old_index; 3821 } 3822 3823 if (MethodComparator::methods_EMCP(old_method, new_method)) { 3824 // The EMCP definition from JSR-163 requires the bytecodes to be 3825 // the same with the exception of constant pool indices which may 3826 // differ. However, the constants referred to by those indices 3827 // must be the same. 3828 // 3829 // We use methods_EMCP() for comparison since constant pool 3830 // merging can remove duplicate constant pool entries that were 3831 // present in the old method and removed from the rewritten new 3832 // method. A faster binary comparison function would consider the 3833 // old and new methods to be different when they are actually 3834 // EMCP. 3835 // 3836 // The old and new methods are EMCP and you would think that we 3837 // could get rid of one of them here and now and save some space. 3838 // However, the concept of EMCP only considers the bytecodes and 3839 // the constant pool entries in the comparison. Other things, 3840 // e.g., the line number table (LNT) or the local variable table 3841 // (LVT) don't count in the comparison. So the new (and EMCP) 3842 // method can have a new LNT that we need so we can't just 3843 // overwrite the new method with the old method. 3844 // 3845 // When this routine is called, we have already attached the new 3846 // methods to the_class so the old methods are effectively 3847 // overwritten. However, if an old method is still executing, 3848 // then the old method cannot be collected until sometime after 3849 // the old method call has returned. So the overwriting of old 3850 // methods by new methods will save us space except for those 3851 // (hopefully few) old methods that are still executing. 3852 // 3853 // A method refers to a ConstMethod* and this presents another 3854 // possible avenue to space savings. The ConstMethod* in the 3855 // new method contains possibly new attributes (LNT, LVT, etc). 3856 // At first glance, it seems possible to save space by replacing 3857 // the ConstMethod* in the old method with the ConstMethod* 3858 // from the new method. The old and new methods would share the 3859 // same ConstMethod* and we would save the space occupied by 3860 // the old ConstMethod*. However, the ConstMethod* contains 3861 // a back reference to the containing method. Sharing the 3862 // ConstMethod* between two methods could lead to confusion in 3863 // the code that uses the back reference. This would lead to 3864 // brittle code that could be broken in non-obvious ways now or 3865 // in the future. 3866 // 3867 // Another possibility is to copy the ConstMethod* from the new 3868 // method to the old method and then overwrite the new method with 3869 // the old method. Since the ConstMethod* contains the bytecodes 3870 // for the method embedded in the oop, this option would change 3871 // the bytecodes out from under any threads executing the old 3872 // method and make the thread's bcp invalid. Since EMCP requires 3873 // that the bytecodes be the same modulo constant pool indices, it 3874 // is straight forward to compute the correct new bcp in the new 3875 // ConstMethod* from the old bcp in the old ConstMethod*. The 3876 // time consuming part would be searching all the frames in all 3877 // of the threads to find all of the calls to the old method. 3878 // 3879 // It looks like we will have to live with the limited savings 3880 // that we get from effectively overwriting the old methods 3881 // when the new methods are attached to the_class. 3882 3883 // Count number of methods that are EMCP. The method will be marked 3884 // old but not obsolete if it is EMCP. 3885 emcp_method_count++; 3886 3887 // An EMCP method is _not_ obsolete. An obsolete method has a 3888 // different jmethodID than the current method. An EMCP method 3889 // has the same jmethodID as the current method. Having the 3890 // same jmethodID for all EMCP versions of a method allows for 3891 // a consistent view of the EMCP methods regardless of which 3892 // EMCP method you happen to have in hand. For example, a 3893 // breakpoint set in one EMCP method will work for all EMCP 3894 // versions of the method including the current one. 3895 } else { 3896 // mark obsolete methods as such 3897 old_method->set_is_obsolete(); 3898 obsolete_count++; 3899 3900 // obsolete methods need a unique idnum so they become new entries in 3901 // the jmethodID cache in InstanceKlass 3902 assert(old_method->method_idnum() == new_method->method_idnum(), "must match"); 3903 u2 num = InstanceKlass::cast(_the_class)->next_method_idnum(); 3904 if (num != ConstMethod::UNSET_IDNUM) { 3905 old_method->set_method_idnum(num); 3906 } 3907 3908 // With tracing we try not to "yack" too much. The position of 3909 // this trace assumes there are fewer obsolete methods than 3910 // EMCP methods. 3911 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) { 3912 ResourceMark rm; 3913 log_trace(redefine, class, obsolete, mark) 3914 ("mark %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string()); 3915 } 3916 } 3917 old_method->set_is_old(); 3918 } 3919 for (int i = 0; i < _deleted_methods_length; ++i) { 3920 Method* old_method = _deleted_methods[i]; 3921 3922 assert(!old_method->has_vtable_index(), 3923 "cannot delete methods with vtable entries");; 3924 3925 // Mark all deleted methods as old, obsolete and deleted 3926 old_method->set_is_deleted(); 3927 old_method->set_is_old(); 3928 old_method->set_is_obsolete(); 3929 ++obsolete_count; 3930 // With tracing we try not to "yack" too much. The position of 3931 // this trace assumes there are fewer obsolete methods than 3932 // EMCP methods. 3933 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) { 3934 ResourceMark rm; 3935 log_trace(redefine, class, obsolete, mark) 3936 ("mark deleted %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string()); 3937 } 3938 } 3939 assert((emcp_method_count + obsolete_count) == _old_methods->length(), 3940 "sanity check"); 3941 log_trace(redefine, class, obsolete, mark)("EMCP_cnt=%d, obsolete_cnt=%d", emcp_method_count, obsolete_count); 3942 return emcp_method_count; 3943 } 3944 3945 // This internal class transfers the native function registration from old methods 3946 // to new methods. It is designed to handle both the simple case of unchanged 3947 // native methods and the complex cases of native method prefixes being added and/or 3948 // removed. 3949 // It expects only to be used during the VM_RedefineClasses op (a safepoint). 3950 // 3951 // This class is used after the new methods have been installed in "the_class". 3952 // 3953 // So, for example, the following must be handled. Where 'm' is a method and 3954 // a number followed by an underscore is a prefix. 3955 // 3956 // Old Name New Name 3957 // Simple transfer to new method m -> m 3958 // Add prefix m -> 1_m 3959 // Remove prefix 1_m -> m 3960 // Simultaneous add of prefixes m -> 3_2_1_m 3961 // Simultaneous removal of prefixes 3_2_1_m -> m 3962 // Simultaneous add and remove 1_m -> 2_m 3963 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m 3964 // 3965 class TransferNativeFunctionRegistration { 3966 private: 3967 InstanceKlass* the_class; 3968 int prefix_count; 3969 char** prefixes; 3970 3971 // Recursively search the binary tree of possibly prefixed method names. 3972 // Iteration could be used if all agents were well behaved. Full tree walk is 3973 // more resilent to agents not cleaning up intermediate methods. 3974 // Branch at each depth in the binary tree is: 3975 // (1) without the prefix. 3976 // (2) with the prefix. 3977 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...) 3978 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len, 3979 Symbol* signature) { 3980 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len); 3981 if (name_symbol != NULL) { 3982 Method* method = the_class->lookup_method(name_symbol, signature); 3983 if (method != NULL) { 3984 // Even if prefixed, intermediate methods must exist. 3985 if (method->is_native()) { 3986 // Wahoo, we found a (possibly prefixed) version of the method, return it. 3987 return method; 3988 } 3989 if (depth < prefix_count) { 3990 // Try applying further prefixes (other than this one). 3991 method = search_prefix_name_space(depth+1, name_str, name_len, signature); 3992 if (method != NULL) { 3993 return method; // found 3994 } 3995 3996 // Try adding this prefix to the method name and see if it matches 3997 // another method name. 3998 char* prefix = prefixes[depth]; 3999 size_t prefix_len = strlen(prefix); 4000 size_t trial_len = name_len + prefix_len; 4001 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1); 4002 strcpy(trial_name_str, prefix); 4003 strcat(trial_name_str, name_str); 4004 method = search_prefix_name_space(depth+1, trial_name_str, trial_len, 4005 signature); 4006 if (method != NULL) { 4007 // If found along this branch, it was prefixed, mark as such 4008 method->set_is_prefixed_native(); 4009 return method; // found 4010 } 4011 } 4012 } 4013 } 4014 return NULL; // This whole branch bore nothing 4015 } 4016 4017 // Return the method name with old prefixes stripped away. 4018 char* method_name_without_prefixes(Method* method) { 4019 Symbol* name = method->name(); 4020 char* name_str = name->as_utf8(); 4021 4022 // Old prefixing may be defunct, strip prefixes, if any. 4023 for (int i = prefix_count-1; i >= 0; i--) { 4024 char* prefix = prefixes[i]; 4025 size_t prefix_len = strlen(prefix); 4026 if (strncmp(prefix, name_str, prefix_len) == 0) { 4027 name_str += prefix_len; 4028 } 4029 } 4030 return name_str; 4031 } 4032 4033 // Strip any prefixes off the old native method, then try to find a 4034 // (possibly prefixed) new native that matches it. 4035 Method* strip_and_search_for_new_native(Method* method) { 4036 ResourceMark rm; 4037 char* name_str = method_name_without_prefixes(method); 4038 return search_prefix_name_space(0, name_str, strlen(name_str), 4039 method->signature()); 4040 } 4041 4042 public: 4043 4044 // Construct a native method transfer processor for this class. 4045 TransferNativeFunctionRegistration(InstanceKlass* _the_class) { 4046 assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); 4047 4048 the_class = _the_class; 4049 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count); 4050 } 4051 4052 // Attempt to transfer any of the old or deleted methods that are native 4053 void transfer_registrations(Method** old_methods, int methods_length) { 4054 for (int j = 0; j < methods_length; j++) { 4055 Method* old_method = old_methods[j]; 4056 4057 if (old_method->is_native() && old_method->has_native_function()) { 4058 Method* new_method = strip_and_search_for_new_native(old_method); 4059 if (new_method != NULL) { 4060 // Actually set the native function in the new method. 4061 // Redefine does not send events (except CFLH), certainly not this 4062 // behind the scenes re-registration. 4063 new_method->set_native_function(old_method->native_function(), 4064 !Method::native_bind_event_is_interesting); 4065 } 4066 } 4067 } 4068 } 4069 }; 4070 4071 // Don't lose the association between a native method and its JNI function. 4072 void VM_RedefineClasses::transfer_old_native_function_registrations(InstanceKlass* the_class) { 4073 TransferNativeFunctionRegistration transfer(the_class); 4074 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length); 4075 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length); 4076 } 4077 4078 // Deoptimize all compiled code that depends on the classes redefined. 4079 // 4080 // If the can_redefine_classes capability is obtained in the onload 4081 // phase then the compiler has recorded all dependencies from startup. 4082 // In that case we need only deoptimize and throw away all compiled code 4083 // that depends on the class. 4084 // 4085 // If can_redefine_classes is obtained sometime after the onload 4086 // phase then the dependency information may be incomplete. In that case 4087 // the first call to RedefineClasses causes all compiled code to be 4088 // thrown away. As can_redefine_classes has been obtained then 4089 // all future compilations will record dependencies so second and 4090 // subsequent calls to RedefineClasses need only throw away code 4091 // that depends on the class. 4092 // 4093 4094 void VM_RedefineClasses::flush_dependent_code() { 4095 assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); 4096 4097 bool deopt_needed; 4098 4099 // This is the first redefinition, mark all the nmethods for deoptimization 4100 if (!JvmtiExport::all_dependencies_are_recorded()) { 4101 log_debug(redefine, class, nmethod)("Marked all nmethods for deopt"); 4102 CodeCache::mark_all_nmethods_for_evol_deoptimization(); 4103 deopt_needed = true; 4104 } else { 4105 int deopt = CodeCache::mark_dependents_for_evol_deoptimization(); 4106 log_debug(redefine, class, nmethod)("Marked %d dependent nmethods for deopt", deopt); 4107 deopt_needed = (deopt != 0); 4108 } 4109 4110 if (deopt_needed) { 4111 CodeCache::flush_evol_dependents(); 4112 } 4113 4114 // From now on we know that the dependency information is complete 4115 JvmtiExport::set_all_dependencies_are_recorded(true); 4116 } 4117 4118 void VM_RedefineClasses::compute_added_deleted_matching_methods() { 4119 Method* old_method; 4120 Method* new_method; 4121 4122 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 4123 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 4124 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length()); 4125 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 4126 4127 _matching_methods_length = 0; 4128 _deleted_methods_length = 0; 4129 _added_methods_length = 0; 4130 4131 int nj = 0; 4132 int oj = 0; 4133 while (true) { 4134 if (oj >= _old_methods->length()) { 4135 if (nj >= _new_methods->length()) { 4136 break; // we've looked at everything, done 4137 } 4138 // New method at the end 4139 new_method = _new_methods->at(nj); 4140 _added_methods[_added_methods_length++] = new_method; 4141 ++nj; 4142 } else if (nj >= _new_methods->length()) { 4143 // Old method, at the end, is deleted 4144 old_method = _old_methods->at(oj); 4145 _deleted_methods[_deleted_methods_length++] = old_method; 4146 ++oj; 4147 } else { 4148 old_method = _old_methods->at(oj); 4149 new_method = _new_methods->at(nj); 4150 if (old_method->name() == new_method->name()) { 4151 if (old_method->signature() == new_method->signature()) { 4152 _matching_old_methods[_matching_methods_length ] = old_method; 4153 _matching_new_methods[_matching_methods_length++] = new_method; 4154 ++nj; 4155 ++oj; 4156 } else { 4157 // added overloaded have already been moved to the end, 4158 // so this is a deleted overloaded method 4159 _deleted_methods[_deleted_methods_length++] = old_method; 4160 ++oj; 4161 } 4162 } else { // names don't match 4163 if (old_method->name()->fast_compare(new_method->name()) > 0) { 4164 // new method 4165 _added_methods[_added_methods_length++] = new_method; 4166 ++nj; 4167 } else { 4168 // deleted method 4169 _deleted_methods[_deleted_methods_length++] = old_method; 4170 ++oj; 4171 } 4172 } 4173 } 4174 } 4175 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity"); 4176 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity"); 4177 } 4178 4179 4180 void VM_RedefineClasses::swap_annotations(InstanceKlass* the_class, 4181 InstanceKlass* scratch_class) { 4182 // Swap annotation fields values 4183 Annotations* old_annotations = the_class->annotations(); 4184 the_class->set_annotations(scratch_class->annotations()); 4185 scratch_class->set_annotations(old_annotations); 4186 } 4187 4188 4189 // Install the redefinition of a class: 4190 // - house keeping (flushing breakpoints and caches, deoptimizing 4191 // dependent compiled code) 4192 // - replacing parts in the_class with parts from scratch_class 4193 // - adding a weak reference to track the obsolete but interesting 4194 // parts of the_class 4195 // - adjusting constant pool caches and vtables in other classes 4196 // that refer to methods in the_class. These adjustments use the 4197 // ClassLoaderDataGraph::classes_do() facility which only allows 4198 // a helper method to be specified. The interesting parameters 4199 // that we would like to pass to the helper method are saved in 4200 // static global fields in the VM operation. 4201 void VM_RedefineClasses::redefine_single_class(Thread* current, jclass the_jclass, 4202 InstanceKlass* scratch_class) { 4203 4204 HandleMark hm(current); // make sure handles from this call are freed 4205 4206 if (log_is_enabled(Info, redefine, class, timer)) { 4207 _timer_rsc_phase1.start(); 4208 } 4209 4210 InstanceKlass* the_class = get_ik(the_jclass); 4211 4212 // Set a flag to control and optimize adjusting method entries 4213 _has_redefined_Object |= the_class == vmClasses::Object_klass(); 4214 4215 // Remove all breakpoints in methods of this class 4216 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints(); 4217 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class); 4218 4219 _old_methods = the_class->methods(); 4220 _new_methods = scratch_class->methods(); 4221 _the_class = the_class; 4222 compute_added_deleted_matching_methods(); 4223 update_jmethod_ids(); 4224 4225 _any_class_has_resolved_methods = the_class->has_resolved_methods() || _any_class_has_resolved_methods; 4226 4227 // Attach new constant pool to the original klass. The original 4228 // klass still refers to the old constant pool (for now). 4229 scratch_class->constants()->set_pool_holder(the_class); 4230 4231 #if 0 4232 // In theory, with constant pool merging in place we should be able 4233 // to save space by using the new, merged constant pool in place of 4234 // the old constant pool(s). By "pool(s)" I mean the constant pool in 4235 // the klass version we are replacing now and any constant pool(s) in 4236 // previous versions of klass. Nice theory, doesn't work in practice. 4237 // When this code is enabled, even simple programs throw NullPointer 4238 // exceptions. I'm guessing that this is caused by some constant pool 4239 // cache difference between the new, merged constant pool and the 4240 // constant pool that was just being used by the klass. I'm keeping 4241 // this code around to archive the idea, but the code has to remain 4242 // disabled for now. 4243 4244 // Attach each old method to the new constant pool. This can be 4245 // done here since we are past the bytecode verification and 4246 // constant pool optimization phases. 4247 for (int i = _old_methods->length() - 1; i >= 0; i--) { 4248 Method* method = _old_methods->at(i); 4249 method->set_constants(scratch_class->constants()); 4250 } 4251 4252 // NOTE: this doesn't work because you can redefine the same class in two 4253 // threads, each getting their own constant pool data appended to the 4254 // original constant pool. In order for the new methods to work when they 4255 // become old methods, they need to keep their updated copy of the constant pool. 4256 4257 { 4258 // walk all previous versions of the klass 4259 InstanceKlass *ik = the_class; 4260 PreviousVersionWalker pvw(ik); 4261 do { 4262 ik = pvw.next_previous_version(); 4263 if (ik != NULL) { 4264 4265 // attach previous version of klass to the new constant pool 4266 ik->set_constants(scratch_class->constants()); 4267 4268 // Attach each method in the previous version of klass to the 4269 // new constant pool 4270 Array<Method*>* prev_methods = ik->methods(); 4271 for (int i = prev_methods->length() - 1; i >= 0; i--) { 4272 Method* method = prev_methods->at(i); 4273 method->set_constants(scratch_class->constants()); 4274 } 4275 } 4276 } while (ik != NULL); 4277 } 4278 #endif 4279 4280 // Replace methods and constantpool 4281 the_class->set_methods(_new_methods); 4282 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods, 4283 // and to be able to undo operation easily. 4284 4285 Array<int>* old_ordering = the_class->method_ordering(); 4286 the_class->set_method_ordering(scratch_class->method_ordering()); 4287 scratch_class->set_method_ordering(old_ordering); 4288 4289 ConstantPool* old_constants = the_class->constants(); 4290 the_class->set_constants(scratch_class->constants()); 4291 scratch_class->set_constants(old_constants); // See the previous comment. 4292 #if 0 4293 // We are swapping the guts of "the new class" with the guts of "the 4294 // class". Since the old constant pool has just been attached to "the 4295 // new class", it seems logical to set the pool holder in the old 4296 // constant pool also. However, doing this will change the observable 4297 // class hierarchy for any old methods that are still executing. A 4298 // method can query the identity of its "holder" and this query uses 4299 // the method's constant pool link to find the holder. The change in 4300 // holding class from "the class" to "the new class" can confuse 4301 // things. 4302 // 4303 // Setting the old constant pool's holder will also cause 4304 // verification done during vtable initialization below to fail. 4305 // During vtable initialization, the vtable's class is verified to be 4306 // a subtype of the method's holder. The vtable's class is "the 4307 // class" and the method's holder is gotten from the constant pool 4308 // link in the method itself. For "the class"'s directly implemented 4309 // methods, the method holder is "the class" itself (as gotten from 4310 // the new constant pool). The check works fine in this case. The 4311 // check also works fine for methods inherited from super classes. 4312 // 4313 // Miranda methods are a little more complicated. A miranda method is 4314 // provided by an interface when the class implementing the interface 4315 // does not provide its own method. These interfaces are implemented 4316 // internally as an InstanceKlass. These special instanceKlasses 4317 // share the constant pool of the class that "implements" the 4318 // interface. By sharing the constant pool, the method holder of a 4319 // miranda method is the class that "implements" the interface. In a 4320 // non-redefine situation, the subtype check works fine. However, if 4321 // the old constant pool's pool holder is modified, then the check 4322 // fails because there is no class hierarchy relationship between the 4323 // vtable's class and "the new class". 4324 4325 old_constants->set_pool_holder(scratch_class()); 4326 #endif 4327 4328 // track number of methods that are EMCP for add_previous_version() call below 4329 int emcp_method_count = check_methods_and_mark_as_obsolete(); 4330 transfer_old_native_function_registrations(the_class); 4331 4332 if (scratch_class->get_cached_class_file() != the_class->get_cached_class_file()) { 4333 // 1. the_class doesn't have a cache yet, scratch_class does have a cache. 4334 // 2. The same class can be present twice in the scratch classes list or there 4335 // are multiple concurrent RetransformClasses calls on different threads. 4336 // the_class and scratch_class have the same cached bytes, but different buffers. 4337 // In such cases we need to deallocate one of the buffers. 4338 // 3. RedefineClasses and the_class has cached bytes from a previous transformation. 4339 // In the case we need to use class bytes from scratch_class. 4340 if (the_class->get_cached_class_file() != nullptr) { 4341 os::free(the_class->get_cached_class_file()); 4342 } 4343 the_class->set_cached_class_file(scratch_class->get_cached_class_file()); 4344 } 4345 4346 // NULL out in scratch class to not delete twice. The class to be redefined 4347 // always owns these bytes. 4348 scratch_class->set_cached_class_file(NULL); 4349 4350 // Replace inner_classes 4351 Array<u2>* old_inner_classes = the_class->inner_classes(); 4352 the_class->set_inner_classes(scratch_class->inner_classes()); 4353 scratch_class->set_inner_classes(old_inner_classes); 4354 4355 // Initialize the vtable and interface table after 4356 // methods have been rewritten 4357 // no exception should happen here since we explicitly 4358 // do not check loader constraints. 4359 // compare_and_normalize_class_versions has already checked: 4360 // - classloaders unchanged, signatures unchanged 4361 // - all instanceKlasses for redefined classes reused & contents updated 4362 the_class->vtable().initialize_vtable(); 4363 the_class->itable().initialize_itable(); 4364 4365 // Leave arrays of jmethodIDs and itable index cache unchanged 4366 4367 // Copy the "source debug extension" attribute from new class version 4368 the_class->set_source_debug_extension( 4369 scratch_class->source_debug_extension(), 4370 scratch_class->source_debug_extension() == NULL ? 0 : 4371 (int)strlen(scratch_class->source_debug_extension())); 4372 4373 // Use of javac -g could be different in the old and the new 4374 if (scratch_class->has_localvariable_table() != 4375 the_class->has_localvariable_table()) { 4376 the_class->set_has_localvariable_table(scratch_class->has_localvariable_table()); 4377 } 4378 4379 swap_annotations(the_class, scratch_class); 4380 4381 // Replace minor version number of class file 4382 u2 old_minor_version = the_class->constants()->minor_version(); 4383 the_class->constants()->set_minor_version(scratch_class->constants()->minor_version()); 4384 scratch_class->constants()->set_minor_version(old_minor_version); 4385 4386 // Replace major version number of class file 4387 u2 old_major_version = the_class->constants()->major_version(); 4388 the_class->constants()->set_major_version(scratch_class->constants()->major_version()); 4389 scratch_class->constants()->set_major_version(old_major_version); 4390 4391 // Replace CP indexes for class and name+type of enclosing method 4392 u2 old_class_idx = the_class->enclosing_method_class_index(); 4393 u2 old_method_idx = the_class->enclosing_method_method_index(); 4394 the_class->set_enclosing_method_indices( 4395 scratch_class->enclosing_method_class_index(), 4396 scratch_class->enclosing_method_method_index()); 4397 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx); 4398 4399 if (!the_class->has_been_redefined()) { 4400 the_class->set_has_been_redefined(); 4401 } 4402 4403 // Scratch class is unloaded but still needs cleaning, and skipping for CDS. 4404 scratch_class->set_is_scratch_class(); 4405 4406 // keep track of previous versions of this class 4407 the_class->add_previous_version(scratch_class, emcp_method_count); 4408 4409 _timer_rsc_phase1.stop(); 4410 if (log_is_enabled(Info, redefine, class, timer)) { 4411 _timer_rsc_phase2.start(); 4412 } 4413 4414 if (the_class->oop_map_cache() != NULL) { 4415 // Flush references to any obsolete methods from the oop map cache 4416 // so that obsolete methods are not pinned. 4417 the_class->oop_map_cache()->flush_obsolete_entries(); 4418 } 4419 4420 increment_class_counter(the_class); 4421 4422 if (EventClassRedefinition::is_enabled()) { 4423 EventClassRedefinition event; 4424 event.set_classModificationCount(java_lang_Class::classRedefinedCount(the_class->java_mirror())); 4425 event.set_redefinedClass(the_class); 4426 event.set_redefinitionId(_id); 4427 event.commit(); 4428 } 4429 4430 { 4431 ResourceMark rm(current); 4432 // increment the classRedefinedCount field in the_class and in any 4433 // direct and indirect subclasses of the_class 4434 log_info(redefine, class, load) 4435 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)", 4436 the_class->external_name(), java_lang_Class::classRedefinedCount(the_class->java_mirror()), os::available_memory() >> 10); 4437 Events::log_redefinition(current, "redefined class name=%s, count=%d", 4438 the_class->external_name(), 4439 java_lang_Class::classRedefinedCount(the_class->java_mirror())); 4440 4441 } 4442 _timer_rsc_phase2.stop(); 4443 4444 } // end redefine_single_class() 4445 4446 4447 // Increment the classRedefinedCount field in the specific InstanceKlass 4448 // and in all direct and indirect subclasses. 4449 void VM_RedefineClasses::increment_class_counter(InstanceKlass* ik) { 4450 for (ClassHierarchyIterator iter(ik); !iter.done(); iter.next()) { 4451 // Only update instanceKlasses 4452 Klass* sub = iter.klass(); 4453 if (sub->is_instance_klass()) { 4454 oop class_mirror = InstanceKlass::cast(sub)->java_mirror(); 4455 Klass* class_oop = java_lang_Class::as_Klass(class_mirror); 4456 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1; 4457 java_lang_Class::set_classRedefinedCount(class_mirror, new_count); 4458 4459 if (class_oop != _the_class) { 4460 // _the_class count is printed at end of redefine_single_class() 4461 log_debug(redefine, class, subclass)("updated count in subclass=%s to %d", ik->external_name(), new_count); 4462 } 4463 } 4464 } 4465 } 4466 4467 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) { 4468 bool no_old_methods = true; // be optimistic 4469 4470 // Both array and instance classes have vtables. 4471 // a vtable should never contain old or obsolete methods 4472 ResourceMark rm(_thread); 4473 if (k->vtable_length() > 0 && 4474 !k->vtable().check_no_old_or_obsolete_entries()) { 4475 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 4476 log_trace(redefine, class, obsolete, metadata) 4477 ("klassVtable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s", 4478 k->signature_name()); 4479 k->vtable().dump_vtable(); 4480 } 4481 no_old_methods = false; 4482 } 4483 4484 if (k->is_instance_klass()) { 4485 HandleMark hm(_thread); 4486 InstanceKlass *ik = InstanceKlass::cast(k); 4487 4488 // an itable should never contain old or obsolete methods 4489 if (ik->itable_length() > 0 && 4490 !ik->itable().check_no_old_or_obsolete_entries()) { 4491 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 4492 log_trace(redefine, class, obsolete, metadata) 4493 ("klassItable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s", 4494 ik->signature_name()); 4495 ik->itable().dump_itable(); 4496 } 4497 no_old_methods = false; 4498 } 4499 4500 // the constant pool cache should never contain non-deleted old or obsolete methods 4501 if (ik->constants() != NULL && 4502 ik->constants()->cache() != NULL && 4503 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) { 4504 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 4505 log_trace(redefine, class, obsolete, metadata) 4506 ("cp-cache::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s", 4507 ik->signature_name()); 4508 ik->constants()->cache()->dump_cache(); 4509 } 4510 no_old_methods = false; 4511 } 4512 } 4513 4514 // print and fail guarantee if old methods are found. 4515 if (!no_old_methods) { 4516 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 4517 dump_methods(); 4518 } else { 4519 log_trace(redefine, class)("Use the '-Xlog:redefine+class*:' option " 4520 "to see more info about the following guarantee() failure."); 4521 } 4522 guarantee(false, "OLD and/or OBSOLETE method(s) found"); 4523 } 4524 } 4525 4526 u8 VM_RedefineClasses::next_id() { 4527 while (true) { 4528 u8 id = _id_counter; 4529 u8 next_id = id + 1; 4530 u8 result = Atomic::cmpxchg(&_id_counter, id, next_id); 4531 if (result == id) { 4532 return next_id; 4533 } 4534 } 4535 } 4536 4537 void VM_RedefineClasses::dump_methods() { 4538 int j; 4539 log_trace(redefine, class, dump)("_old_methods --"); 4540 for (j = 0; j < _old_methods->length(); ++j) { 4541 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4542 Method* m = _old_methods->at(j); 4543 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4544 m->access_flags().print_on(&log_stream); 4545 log_stream.print(" -- "); 4546 m->print_name(&log_stream); 4547 log_stream.cr(); 4548 } 4549 log_trace(redefine, class, dump)("_new_methods --"); 4550 for (j = 0; j < _new_methods->length(); ++j) { 4551 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4552 Method* m = _new_methods->at(j); 4553 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4554 m->access_flags().print_on(&log_stream); 4555 log_stream.print(" -- "); 4556 m->print_name(&log_stream); 4557 log_stream.cr(); 4558 } 4559 log_trace(redefine, class, dump)("_matching_methods --"); 4560 for (j = 0; j < _matching_methods_length; ++j) { 4561 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4562 Method* m = _matching_old_methods[j]; 4563 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4564 m->access_flags().print_on(&log_stream); 4565 log_stream.print(" -- "); 4566 m->print_name(); 4567 log_stream.cr(); 4568 4569 m = _matching_new_methods[j]; 4570 log_stream.print(" (%5d) ", m->vtable_index()); 4571 m->access_flags().print_on(&log_stream); 4572 log_stream.cr(); 4573 } 4574 log_trace(redefine, class, dump)("_deleted_methods --"); 4575 for (j = 0; j < _deleted_methods_length; ++j) { 4576 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4577 Method* m = _deleted_methods[j]; 4578 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4579 m->access_flags().print_on(&log_stream); 4580 log_stream.print(" -- "); 4581 m->print_name(&log_stream); 4582 log_stream.cr(); 4583 } 4584 log_trace(redefine, class, dump)("_added_methods --"); 4585 for (j = 0; j < _added_methods_length; ++j) { 4586 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4587 Method* m = _added_methods[j]; 4588 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4589 m->access_flags().print_on(&log_stream); 4590 log_stream.print(" -- "); 4591 m->print_name(&log_stream); 4592 log_stream.cr(); 4593 } 4594 } 4595 4596 void VM_RedefineClasses::print_on_error(outputStream* st) const { 4597 VM_Operation::print_on_error(st); 4598 if (_the_class != NULL) { 4599 ResourceMark rm; 4600 st->print_cr(", redefining class %s", _the_class->external_name()); 4601 } 4602 }