1 /* 2 * Copyright (c) 2003, 2025, 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 "cds/cdsConfig.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/klassFactory.hpp" 32 #include "classfile/metadataOnStackMark.hpp" 33 #include "classfile/stackMapTable.hpp" 34 #include "classfile/symbolTable.hpp" 35 #include "classfile/verifier.hpp" 36 #include "classfile/vmClasses.hpp" 37 #include "classfile/vmSymbols.hpp" 38 #include "code/codeCache.hpp" 39 #include "compiler/compileBroker.hpp" 40 #include "interpreter/oopMapCache.hpp" 41 #include "interpreter/rewriter.hpp" 42 #include "jfr/jfrEvents.hpp" 43 #include "logging/logStream.hpp" 44 #include "memory/metadataFactory.hpp" 45 #include "memory/resourceArea.hpp" 46 #include "memory/universe.hpp" 47 #include "oops/annotations.hpp" 48 #include "oops/constantPool.hpp" 49 #include "oops/fieldStreams.inline.hpp" 50 #include "oops/klass.inline.hpp" 51 #include "oops/klassVtable.hpp" 52 #include "oops/method.hpp" 53 #include "oops/oop.inline.hpp" 54 #include "oops/recordComponent.hpp" 55 #include "prims/jvmtiImpl.hpp" 56 #include "prims/jvmtiRedefineClasses.hpp" 57 #include "prims/jvmtiThreadState.inline.hpp" 58 #include "prims/methodComparator.hpp" 59 #include "prims/resolvedMethodTable.hpp" 60 #include "runtime/atomic.hpp" 61 #include "runtime/deoptimization.hpp" 62 #include "runtime/handles.inline.hpp" 63 #include "runtime/jniHandles.inline.hpp" 64 #include "runtime/relocator.hpp" 65 #include "runtime/safepointVerifiers.hpp" 66 #include "utilities/bitMap.inline.hpp" 67 #include "utilities/checkedCast.hpp" 68 #include "utilities/events.hpp" 69 #include "utilities/macros.hpp" 70 #if INCLUDE_JFR 71 #include "jfr/jfr.hpp" 72 #endif 73 74 Array<Method*>* VM_RedefineClasses::_old_methods = nullptr; 75 Array<Method*>* VM_RedefineClasses::_new_methods = nullptr; 76 Method** VM_RedefineClasses::_matching_old_methods = nullptr; 77 Method** VM_RedefineClasses::_matching_new_methods = nullptr; 78 Method** VM_RedefineClasses::_deleted_methods = nullptr; 79 Method** VM_RedefineClasses::_added_methods = nullptr; 80 int VM_RedefineClasses::_matching_methods_length = 0; 81 int VM_RedefineClasses::_deleted_methods_length = 0; 82 int VM_RedefineClasses::_added_methods_length = 0; 83 84 // This flag is global as the constructor does not reset it: 85 bool VM_RedefineClasses::_has_redefined_Object = false; 86 u8 VM_RedefineClasses::_id_counter = 0; 87 88 VM_RedefineClasses::VM_RedefineClasses(jint class_count, 89 const jvmtiClassDefinition *class_defs, 90 JvmtiClassLoadKind class_load_kind) { 91 _class_count = class_count; 92 _class_defs = class_defs; 93 _class_load_kind = class_load_kind; 94 _any_class_has_resolved_methods = false; 95 _res = JVMTI_ERROR_NONE; 96 _the_class = nullptr; 97 _id = next_id(); 98 } 99 100 static inline InstanceKlass* get_ik(jclass def) { 101 oop mirror = JNIHandles::resolve_non_null(def); 102 return InstanceKlass::cast(java_lang_Class::as_Klass(mirror)); 103 } 104 105 // If any of the classes are being redefined, wait 106 // Parallel constant pool merging leads to indeterminate constant pools. 107 void VM_RedefineClasses::lock_classes() { 108 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current()); 109 GrowableArray<Klass*>* redef_classes = state->get_classes_being_redefined(); 110 111 MonitorLocker ml(RedefineClasses_lock); 112 113 if (redef_classes == nullptr) { 114 redef_classes = new (mtClass) GrowableArray<Klass*>(1, mtClass); 115 state->set_classes_being_redefined(redef_classes); 116 } 117 118 bool has_redefined; 119 do { 120 has_redefined = false; 121 // Go through classes each time until none are being redefined. Skip 122 // the ones that are being redefined by this thread currently. Class file 123 // load hook event may trigger new class redefine when we are redefining 124 // a class (after lock_classes()). 125 for (int i = 0; i < _class_count; i++) { 126 InstanceKlass* ik = get_ik(_class_defs[i].klass); 127 // Check if we are currently redefining the class in this thread already. 128 if (redef_classes->contains(ik)) { 129 assert(ik->is_being_redefined(), "sanity"); 130 } else { 131 if (ik->is_being_redefined()) { 132 ml.wait(); 133 has_redefined = true; 134 break; // for loop 135 } 136 } 137 } 138 } while (has_redefined); 139 140 for (int i = 0; i < _class_count; i++) { 141 InstanceKlass* ik = get_ik(_class_defs[i].klass); 142 redef_classes->push(ik); // Add to the _classes_being_redefined list 143 ik->set_is_being_redefined(true); 144 } 145 ml.notify_all(); 146 } 147 148 void VM_RedefineClasses::unlock_classes() { 149 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current()); 150 GrowableArray<Klass*>* redef_classes = state->get_classes_being_redefined(); 151 assert(redef_classes != nullptr, "_classes_being_redefined is not allocated"); 152 153 MonitorLocker ml(RedefineClasses_lock); 154 155 for (int i = _class_count - 1; i >= 0; i--) { 156 InstanceKlass* def_ik = get_ik(_class_defs[i].klass); 157 if (redef_classes->length() > 0) { 158 // Remove the class from _classes_being_redefined list 159 Klass* k = redef_classes->pop(); 160 assert(def_ik == k, "unlocking wrong class"); 161 } 162 assert(def_ik->is_being_redefined(), 163 "should be being redefined to get here"); 164 165 // Unlock after we finish all redefines for this class within 166 // the thread. Same class can be pushed to the list multiple 167 // times (not more than once by each recursive redefinition). 168 if (!redef_classes->contains(def_ik)) { 169 def_ik->set_is_being_redefined(false); 170 } 171 } 172 ml.notify_all(); 173 } 174 175 bool VM_RedefineClasses::doit_prologue() { 176 if (_class_count == 0) { 177 _res = JVMTI_ERROR_NONE; 178 return false; 179 } 180 if (_class_defs == nullptr) { 181 _res = JVMTI_ERROR_NULL_POINTER; 182 return false; 183 } 184 185 for (int i = 0; i < _class_count; i++) { 186 if (_class_defs[i].klass == nullptr) { 187 _res = JVMTI_ERROR_INVALID_CLASS; 188 return false; 189 } 190 if (_class_defs[i].class_byte_count == 0) { 191 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT; 192 return false; 193 } 194 if (_class_defs[i].class_bytes == nullptr) { 195 _res = JVMTI_ERROR_NULL_POINTER; 196 return false; 197 } 198 199 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass); 200 // classes for primitives, arrays, and hidden classes 201 // cannot be redefined. 202 if (!is_modifiable_class(mirror)) { 203 _res = JVMTI_ERROR_UNMODIFIABLE_CLASS; 204 return false; 205 } 206 } 207 208 // Start timer after all the sanity checks; not quite accurate, but 209 // better than adding a bunch of stop() calls. 210 if (log_is_enabled(Info, redefine, class, timer)) { 211 _timer_vm_op_prologue.start(); 212 } 213 214 lock_classes(); 215 // We first load new class versions in the prologue, because somewhere down the 216 // call chain it is required that the current thread is a Java thread. 217 _res = load_new_class_versions(); 218 if (_res != JVMTI_ERROR_NONE) { 219 // free any successfully created classes, since none are redefined 220 for (int i = 0; i < _class_count; i++) { 221 if (_scratch_classes[i] != nullptr) { 222 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data(); 223 // Free the memory for this class at class unloading time. Not before 224 // because CMS might think this is still live. 225 InstanceKlass* ik = get_ik(_class_defs[i].klass); 226 if (ik->get_cached_class_file() == _scratch_classes[i]->get_cached_class_file()) { 227 // Don't double-free cached_class_file copied from the original class if error. 228 _scratch_classes[i]->set_cached_class_file(nullptr); 229 } 230 cld->add_to_deallocate_list(InstanceKlass::cast(_scratch_classes[i])); 231 } 232 } 233 // Free os::malloc allocated memory in load_new_class_version. 234 os::free(_scratch_classes); 235 _timer_vm_op_prologue.stop(); 236 unlock_classes(); 237 return false; 238 } 239 240 _timer_vm_op_prologue.stop(); 241 return true; 242 } 243 244 void VM_RedefineClasses::doit() { 245 Thread* current = Thread::current(); 246 247 if (log_is_enabled(Info, redefine, class, timer)) { 248 _timer_vm_op_doit.start(); 249 } 250 251 #if INCLUDE_CDS 252 if (CDSConfig::is_using_archive()) { 253 // Sharing is enabled so we remap the shared readonly space to 254 // shared readwrite, private just in case we need to redefine 255 // a shared class. We do the remap during the doit() phase of 256 // the safepoint to be safer. 257 if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) { 258 log_info(redefine, class, load)("failed to remap shared readonly space to readwrite, private"); 259 _res = JVMTI_ERROR_INTERNAL; 260 _timer_vm_op_doit.stop(); 261 return; 262 } 263 } 264 #endif 265 266 // Mark methods seen on stack and everywhere else so old methods are not 267 // cleaned up if they're on the stack. 268 MetadataOnStackMark md_on_stack(/*walk_all_metadata*/true, /*redefinition_walk*/true); 269 HandleMark hm(current); // make sure any handles created are deleted 270 // before the stack walk again. 271 272 for (int i = 0; i < _class_count; i++) { 273 redefine_single_class(current, _class_defs[i].klass, _scratch_classes[i]); 274 } 275 276 // Flush all compiled code that depends on the classes redefined. 277 flush_dependent_code(); 278 279 // Adjust constantpool caches and vtables for all classes 280 // that reference methods of the evolved classes. 281 // Have to do this after all classes are redefined and all methods that 282 // are redefined are marked as old. 283 AdjustAndCleanMetadata adjust_and_clean_metadata(current); 284 ClassLoaderDataGraph::classes_do(&adjust_and_clean_metadata); 285 286 // JSR-292 support 287 if (_any_class_has_resolved_methods) { 288 bool trace_name_printed = false; 289 ResolvedMethodTable::adjust_method_entries(&trace_name_printed); 290 } 291 292 // Increment flag indicating that some invariants are no longer true. 293 // See jvmtiExport.hpp for detailed explanation. 294 JvmtiExport::increment_redefinition_count(); 295 296 // check_class() is optionally called for product bits, but is 297 // always called for non-product bits. 298 #ifdef PRODUCT 299 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 300 #endif 301 log_trace(redefine, class, obsolete, metadata)("calling check_class"); 302 CheckClass check_class(current); 303 ClassLoaderDataGraph::classes_do(&check_class); 304 #ifdef PRODUCT 305 } 306 #endif 307 308 // Clean up any metadata now unreferenced while MetadataOnStackMark is set. 309 ClassLoaderDataGraph::clean_deallocate_lists(false); 310 311 _timer_vm_op_doit.stop(); 312 } 313 314 void VM_RedefineClasses::doit_epilogue() { 315 unlock_classes(); 316 317 // Free os::malloc allocated memory. 318 os::free(_scratch_classes); 319 320 // Reset the_class to null for error printing. 321 _the_class = nullptr; 322 323 if (log_is_enabled(Info, redefine, class, timer)) { 324 // Used to have separate timers for "doit" and "all", but the timer 325 // overhead skewed the measurements. 326 julong doit_time = _timer_vm_op_doit.milliseconds(); 327 julong all_time = _timer_vm_op_prologue.milliseconds() + doit_time; 328 329 log_info(redefine, class, timer) 330 ("vm_op: all=" JULONG_FORMAT " prologue=" JULONG_FORMAT " doit=" JULONG_FORMAT, 331 all_time, (julong)_timer_vm_op_prologue.milliseconds(), doit_time); 332 log_info(redefine, class, timer) 333 ("redefine_single_class: phase1=" JULONG_FORMAT " phase2=" JULONG_FORMAT, 334 (julong)_timer_rsc_phase1.milliseconds(), (julong)_timer_rsc_phase2.milliseconds()); 335 } 336 } 337 338 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) { 339 // classes for primitives cannot be redefined 340 if (java_lang_Class::is_primitive(klass_mirror)) { 341 return false; 342 } 343 Klass* k = java_lang_Class::as_Klass(klass_mirror); 344 // classes for arrays cannot be redefined 345 if (k == nullptr || !k->is_instance_klass()) { 346 return false; 347 } 348 349 // Cannot redefine or retransform a hidden class. 350 if (InstanceKlass::cast(k)->is_hidden()) { 351 return false; 352 } 353 if (InstanceKlass::cast(k) == vmClasses::Continuation_klass()) { 354 // Don't redefine Continuation class. See 8302779. 355 return false; 356 } 357 return true; 358 } 359 360 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p 361 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For 362 // direct CP entries, there is just the current entry to append. For 363 // indirect and double-indirect CP entries, there are zero or more 364 // referenced CP entries along with the current entry to append. 365 // Indirect and double-indirect CP entries are handled by recursive 366 // calls to append_entry() as needed. The referenced CP entries are 367 // always appended to *merge_cp_p before the referee CP entry. These 368 // referenced CP entries may already exist in *merge_cp_p in which case 369 // there is nothing extra to append and only the current entry is 370 // appended. 371 void VM_RedefineClasses::append_entry(const constantPoolHandle& scratch_cp, 372 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) { 373 374 // append is different depending on entry tag type 375 switch (scratch_cp->tag_at(scratch_i).value()) { 376 377 // The old verifier is implemented outside the VM. It loads classes, 378 // but does not resolve constant pool entries directly so we never 379 // see Class entries here with the old verifier. Similarly the old 380 // verifier does not like Class entries in the input constant pool. 381 // The split-verifier is implemented in the VM so it can optionally 382 // and directly resolve constant pool entries to load classes. The 383 // split-verifier can accept either Class entries or UnresolvedClass 384 // entries in the input constant pool. We revert the appended copy 385 // back to UnresolvedClass so that either verifier will be happy 386 // with the constant pool entry. 387 // 388 // this is an indirect CP entry so it needs special handling 389 case JVM_CONSTANT_Class: 390 case JVM_CONSTANT_UnresolvedClass: 391 { 392 int name_i = scratch_cp->klass_name_index_at(scratch_i); 393 int new_name_i = find_or_append_indirect_entry(scratch_cp, name_i, merge_cp_p, 394 merge_cp_length_p); 395 396 if (new_name_i != name_i) { 397 log_trace(redefine, class, constantpool) 398 ("Class entry@%d name_index change: %d to %d", 399 *merge_cp_length_p, name_i, new_name_i); 400 } 401 402 (*merge_cp_p)->temp_unresolved_klass_at_put(*merge_cp_length_p, new_name_i); 403 if (scratch_i != *merge_cp_length_p) { 404 // The new entry in *merge_cp_p is at a different index than 405 // the new entry in scratch_cp so we need to map the index values. 406 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 407 } 408 (*merge_cp_length_p)++; 409 } break; 410 411 // these are direct CP entries so they can be directly appended, 412 // but double and long take two constant pool entries 413 case JVM_CONSTANT_Double: // fall through 414 case JVM_CONSTANT_Long: 415 { 416 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p); 417 418 if (scratch_i != *merge_cp_length_p) { 419 // The new entry in *merge_cp_p is at a different index than 420 // the new entry in scratch_cp so we need to map the index values. 421 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 422 } 423 (*merge_cp_length_p) += 2; 424 } break; 425 426 // these are direct CP entries so they can be directly appended 427 case JVM_CONSTANT_Float: // fall through 428 case JVM_CONSTANT_Integer: // fall through 429 case JVM_CONSTANT_Utf8: // fall through 430 431 // This was an indirect CP entry, but it has been changed into 432 // Symbol*s so this entry can be directly appended. 433 case JVM_CONSTANT_String: // fall through 434 { 435 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p); 436 437 if (scratch_i != *merge_cp_length_p) { 438 // The new entry in *merge_cp_p is at a different index than 439 // the new entry in scratch_cp so we need to map the index values. 440 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 441 } 442 (*merge_cp_length_p)++; 443 } break; 444 445 // this is an indirect CP entry so it needs special handling 446 case JVM_CONSTANT_NameAndType: 447 { 448 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i); 449 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p, 450 merge_cp_length_p); 451 452 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i); 453 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i, 454 merge_cp_p, merge_cp_length_p); 455 456 // If the referenced entries already exist in *merge_cp_p, then 457 // both new_name_ref_i and new_signature_ref_i will both be 0. 458 // In that case, all we are appending is the current entry. 459 if (new_name_ref_i != name_ref_i) { 460 log_trace(redefine, class, constantpool) 461 ("NameAndType entry@%d name_ref_index change: %d to %d", 462 *merge_cp_length_p, name_ref_i, new_name_ref_i); 463 } 464 if (new_signature_ref_i != signature_ref_i) { 465 log_trace(redefine, class, constantpool) 466 ("NameAndType entry@%d signature_ref_index change: %d to %d", 467 *merge_cp_length_p, signature_ref_i, new_signature_ref_i); 468 } 469 470 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p, 471 new_name_ref_i, new_signature_ref_i); 472 if (scratch_i != *merge_cp_length_p) { 473 // The new entry in *merge_cp_p is at a different index than 474 // the new entry in scratch_cp so we need to map the index values. 475 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 476 } 477 (*merge_cp_length_p)++; 478 } break; 479 480 // this is a double-indirect CP entry so it needs special handling 481 case JVM_CONSTANT_Fieldref: // fall through 482 case JVM_CONSTANT_InterfaceMethodref: // fall through 483 case JVM_CONSTANT_Methodref: 484 { 485 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i); 486 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i, 487 merge_cp_p, merge_cp_length_p); 488 489 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i); 490 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i, 491 merge_cp_p, merge_cp_length_p); 492 493 const char *entry_name = nullptr; 494 switch (scratch_cp->tag_at(scratch_i).value()) { 495 case JVM_CONSTANT_Fieldref: 496 entry_name = "Fieldref"; 497 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i, 498 new_name_and_type_ref_i); 499 break; 500 case JVM_CONSTANT_InterfaceMethodref: 501 entry_name = "IFMethodref"; 502 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p, 503 new_klass_ref_i, new_name_and_type_ref_i); 504 break; 505 case JVM_CONSTANT_Methodref: 506 entry_name = "Methodref"; 507 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i, 508 new_name_and_type_ref_i); 509 break; 510 default: 511 guarantee(false, "bad switch"); 512 break; 513 } 514 515 if (klass_ref_i != new_klass_ref_i) { 516 log_trace(redefine, class, constantpool) 517 ("%s entry@%d class_index changed: %d to %d", entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i); 518 } 519 if (name_and_type_ref_i != new_name_and_type_ref_i) { 520 log_trace(redefine, class, constantpool) 521 ("%s entry@%d name_and_type_index changed: %d to %d", 522 entry_name, *merge_cp_length_p, name_and_type_ref_i, new_name_and_type_ref_i); 523 } 524 525 if (scratch_i != *merge_cp_length_p) { 526 // The new entry in *merge_cp_p is at a different index than 527 // the new entry in scratch_cp so we need to map the index values. 528 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 529 } 530 (*merge_cp_length_p)++; 531 } break; 532 533 // this is an indirect CP entry so it needs special handling 534 case JVM_CONSTANT_MethodType: 535 { 536 int ref_i = scratch_cp->method_type_index_at(scratch_i); 537 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p, 538 merge_cp_length_p); 539 if (new_ref_i != ref_i) { 540 log_trace(redefine, class, constantpool) 541 ("MethodType entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i); 542 } 543 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i); 544 if (scratch_i != *merge_cp_length_p) { 545 // The new entry in *merge_cp_p is at a different index than 546 // the new entry in scratch_cp so we need to map the index values. 547 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 548 } 549 (*merge_cp_length_p)++; 550 } break; 551 552 // this is an indirect CP entry so it needs special handling 553 case JVM_CONSTANT_MethodHandle: 554 { 555 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i); 556 int ref_i = scratch_cp->method_handle_index_at(scratch_i); 557 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p, 558 merge_cp_length_p); 559 if (new_ref_i != ref_i) { 560 log_trace(redefine, class, constantpool) 561 ("MethodHandle entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i); 562 } 563 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i); 564 if (scratch_i != *merge_cp_length_p) { 565 // The new entry in *merge_cp_p is at a different index than 566 // the new entry in scratch_cp so we need to map the index values. 567 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 568 } 569 (*merge_cp_length_p)++; 570 } break; 571 572 // this is an indirect CP entry so it needs special handling 573 case JVM_CONSTANT_Dynamic: // fall through 574 case JVM_CONSTANT_InvokeDynamic: 575 { 576 // Index of the bootstrap specifier in the operands array 577 int old_bs_i = scratch_cp->bootstrap_methods_attribute_index(scratch_i); 578 int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p, 579 merge_cp_length_p); 580 // The bootstrap method NameAndType_info index 581 int old_ref_i = scratch_cp->bootstrap_name_and_type_ref_index_at(scratch_i); 582 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p, 583 merge_cp_length_p); 584 if (new_bs_i != old_bs_i) { 585 log_trace(redefine, class, constantpool) 586 ("Dynamic entry@%d bootstrap_method_attr_index change: %d to %d", 587 *merge_cp_length_p, old_bs_i, new_bs_i); 588 } 589 if (new_ref_i != old_ref_i) { 590 log_trace(redefine, class, constantpool) 591 ("Dynamic entry@%d name_and_type_index change: %d to %d", *merge_cp_length_p, old_ref_i, new_ref_i); 592 } 593 594 if (scratch_cp->tag_at(scratch_i).is_dynamic_constant()) 595 (*merge_cp_p)->dynamic_constant_at_put(*merge_cp_length_p, new_bs_i, new_ref_i); 596 else 597 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i); 598 if (scratch_i != *merge_cp_length_p) { 599 // The new entry in *merge_cp_p is at a different index than 600 // the new entry in scratch_cp so we need to map the index values. 601 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 602 } 603 (*merge_cp_length_p)++; 604 } break; 605 606 // At this stage, Class or UnresolvedClass could be in scratch_cp, but not 607 // ClassIndex 608 case JVM_CONSTANT_ClassIndex: // fall through 609 610 // Invalid is used as the tag for the second constant pool entry 611 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should 612 // not be seen by itself. 613 case JVM_CONSTANT_Invalid: // fall through 614 615 // At this stage, String could be here, but not StringIndex 616 case JVM_CONSTANT_StringIndex: // fall through 617 618 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be 619 // here 620 case JVM_CONSTANT_UnresolvedClassInError: // fall through 621 622 default: 623 { 624 // leave a breadcrumb 625 jbyte bad_value = scratch_cp->tag_at(scratch_i).value(); 626 ShouldNotReachHere(); 627 } break; 628 } // end switch tag value 629 } // end append_entry() 630 631 632 u2 VM_RedefineClasses::find_or_append_indirect_entry(const constantPoolHandle& scratch_cp, 633 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) { 634 635 int new_ref_i = ref_i; 636 bool match = (ref_i < *merge_cp_length_p) && 637 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i); 638 639 if (!match) { 640 // forward reference in *merge_cp_p or not a direct match 641 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p); 642 if (found_i != 0) { 643 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree"); 644 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry. 645 new_ref_i = found_i; 646 map_index(scratch_cp, ref_i, found_i); 647 } else { 648 // no match found so we have to append this entry to *merge_cp_p 649 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p); 650 // The above call to append_entry() can only append one entry 651 // so the post call query of *merge_cp_length_p is only for 652 // the sake of consistency. 653 new_ref_i = *merge_cp_length_p - 1; 654 } 655 } 656 657 // constant pool indices are u2, unless the merged constant pool overflows which 658 // we don't check for. 659 return checked_cast<u2>(new_ref_i); 660 } // end find_or_append_indirect_entry() 661 662 663 // Append a bootstrap specifier into the merge_cp operands that is semantically equal 664 // to the scratch_cp operands bootstrap specifier passed by the old_bs_i index. 665 // Recursively append new merge_cp entries referenced by the new bootstrap specifier. 666 void VM_RedefineClasses::append_operand(const constantPoolHandle& scratch_cp, const int old_bs_i, 667 constantPoolHandle *merge_cp_p, int *merge_cp_length_p) { 668 669 BSMAttributeEntry* old_bsme = scratch_cp->bsm_attribute_entry(old_bs_i); 670 u2 old_ref_i = old_bsme->bootstrap_method_index(); 671 u2 new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p, 672 merge_cp_length_p); 673 if (new_ref_i != old_ref_i) { 674 log_trace(redefine, class, constantpool) 675 ("operands entry@%d bootstrap method ref_index change: %d to %d", _operands_cur_length, old_ref_i, new_ref_i); 676 } 677 678 Array<u2>* merge_ops = (*merge_cp_p)->operands(); 679 int new_bs_i = _operands_cur_length; 680 // We have _operands_cur_length == 0 when the merge_cp operands is empty yet. 681 // However, the operand_offset_at(0) was set in the extend_operands() call. 682 int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0) 683 : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1); 684 u2 argc = old_bsme->argument_count(); 685 686 ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base); 687 merge_ops->at_put(new_base++, new_ref_i); 688 merge_ops->at_put(new_base++, argc); 689 690 for (int i = 0; i < argc; i++) { 691 u2 old_arg_ref_i = old_bsme->argument_index(i); 692 u2 new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p, 693 merge_cp_length_p); 694 merge_ops->at_put(new_base++, new_arg_ref_i); 695 if (new_arg_ref_i != old_arg_ref_i) { 696 log_trace(redefine, class, constantpool) 697 ("operands entry@%d bootstrap method argument ref_index change: %d to %d", 698 _operands_cur_length, old_arg_ref_i, new_arg_ref_i); 699 } 700 } 701 if (old_bs_i != _operands_cur_length) { 702 // The bootstrap specifier in *merge_cp_p is at a different index than 703 // that in scratch_cp so we need to map the index values. 704 map_operand_index(old_bs_i, new_bs_i); 705 } 706 _operands_cur_length++; 707 } // end append_operand() 708 709 710 int VM_RedefineClasses::find_or_append_operand(const constantPoolHandle& scratch_cp, 711 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) { 712 713 int new_bs_i = old_bs_i; // bootstrap specifier index 714 bool match = (old_bs_i < _operands_cur_length) && 715 scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i); 716 717 if (!match) { 718 // forward reference in *merge_cp_p or not a direct match 719 int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p, 720 _operands_cur_length); 721 if (found_i != -1) { 722 guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree"); 723 // found a matching operand somewhere else in *merge_cp_p so just need a mapping 724 new_bs_i = found_i; 725 map_operand_index(old_bs_i, found_i); 726 } else { 727 // no match found so we have to append this bootstrap specifier to *merge_cp_p 728 append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p); 729 new_bs_i = _operands_cur_length - 1; 730 } 731 } 732 return new_bs_i; 733 } // end find_or_append_operand() 734 735 736 void VM_RedefineClasses::finalize_operands_merge(const constantPoolHandle& merge_cp, TRAPS) { 737 if (merge_cp->operands() == nullptr) { 738 return; 739 } 740 // Shrink the merge_cp operands 741 merge_cp->shrink_operands(_operands_cur_length, CHECK); 742 743 if (log_is_enabled(Trace, redefine, class, constantpool)) { 744 // don't want to loop unless we are tracing 745 int count = 0; 746 for (int i = 1; i < _operands_index_map_p->length(); i++) { 747 int value = _operands_index_map_p->at(i); 748 if (value != -1) { 749 log_trace(redefine, class, constantpool)("operands_index_map[%d]: old=%d new=%d", count, i, value); 750 count++; 751 } 752 } 753 } 754 // Clean-up 755 _operands_index_map_p = nullptr; 756 _operands_cur_length = 0; 757 _operands_index_map_count = 0; 758 } // end finalize_operands_merge() 759 760 // Symbol* comparator for qsort 761 // The caller must have an active ResourceMark. 762 static int symcmp(const void* a, const void* b) { 763 char* astr = (*(Symbol**)a)->as_C_string(); 764 char* bstr = (*(Symbol**)b)->as_C_string(); 765 return strcmp(astr, bstr); 766 } 767 768 // The caller must have an active ResourceMark. 769 static jvmtiError check_attribute_arrays(const char* attr_name, 770 InstanceKlass* the_class, InstanceKlass* scratch_class, 771 Array<u2>* the_array, Array<u2>* scr_array) { 772 bool the_array_exists = the_array != Universe::the_empty_short_array(); 773 bool scr_array_exists = scr_array != Universe::the_empty_short_array(); 774 775 int array_len = the_array->length(); 776 if (the_array_exists && scr_array_exists) { 777 if (array_len != scr_array->length()) { 778 log_trace(redefine, class) 779 ("redefined class %s attribute change error: %s len=%d changed to len=%d", 780 the_class->external_name(), attr_name, array_len, scr_array->length()); 781 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 782 } 783 784 // The order of entries in the attribute array is not specified so we 785 // have to explicitly check for the same contents. We do this by copying 786 // the referenced symbols into their own arrays, sorting them and then 787 // comparing each element pair. 788 789 Symbol** the_syms = NEW_RESOURCE_ARRAY_RETURN_NULL(Symbol*, array_len); 790 Symbol** scr_syms = NEW_RESOURCE_ARRAY_RETURN_NULL(Symbol*, array_len); 791 792 if (the_syms == nullptr || scr_syms == nullptr) { 793 return JVMTI_ERROR_OUT_OF_MEMORY; 794 } 795 796 for (int i = 0; i < array_len; i++) { 797 int the_cp_index = the_array->at(i); 798 int scr_cp_index = scr_array->at(i); 799 the_syms[i] = the_class->constants()->klass_name_at(the_cp_index); 800 scr_syms[i] = scratch_class->constants()->klass_name_at(scr_cp_index); 801 } 802 803 qsort(the_syms, array_len, sizeof(Symbol*), symcmp); 804 qsort(scr_syms, array_len, sizeof(Symbol*), symcmp); 805 806 for (int i = 0; i < array_len; i++) { 807 if (the_syms[i] != scr_syms[i]) { 808 log_info(redefine, class) 809 ("redefined class %s attribute change error: %s[%d]: %s changed to %s", 810 the_class->external_name(), attr_name, i, 811 the_syms[i]->as_C_string(), scr_syms[i]->as_C_string()); 812 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 813 } 814 } 815 } else if (the_array_exists ^ scr_array_exists) { 816 const char* action_str = (the_array_exists) ? "removed" : "added"; 817 log_info(redefine, class) 818 ("redefined class %s attribute change error: %s attribute %s", 819 the_class->external_name(), attr_name, action_str); 820 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 821 } 822 return JVMTI_ERROR_NONE; 823 } 824 825 static jvmtiError check_nest_attributes(InstanceKlass* the_class, 826 InstanceKlass* scratch_class) { 827 // Check whether the class NestHost attribute has been changed. 828 Thread* thread = Thread::current(); 829 ResourceMark rm(thread); 830 u2 the_nest_host_idx = the_class->nest_host_index(); 831 u2 scr_nest_host_idx = scratch_class->nest_host_index(); 832 833 if (the_nest_host_idx != 0 && scr_nest_host_idx != 0) { 834 Symbol* the_sym = the_class->constants()->klass_name_at(the_nest_host_idx); 835 Symbol* scr_sym = scratch_class->constants()->klass_name_at(scr_nest_host_idx); 836 if (the_sym != scr_sym) { 837 log_info(redefine, class, nestmates) 838 ("redefined class %s attribute change error: NestHost class: %s replaced with: %s", 839 the_class->external_name(), the_sym->as_C_string(), scr_sym->as_C_string()); 840 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 841 } 842 } else if ((the_nest_host_idx == 0) ^ (scr_nest_host_idx == 0)) { 843 const char* action_str = (the_nest_host_idx != 0) ? "removed" : "added"; 844 log_info(redefine, class, nestmates) 845 ("redefined class %s attribute change error: NestHost attribute %s", 846 the_class->external_name(), action_str); 847 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 848 } 849 850 // Check whether the class NestMembers attribute has been changed. 851 return check_attribute_arrays("NestMembers", 852 the_class, scratch_class, 853 the_class->nest_members(), 854 scratch_class->nest_members()); 855 } 856 857 // Return an error status if the class Record attribute was changed. 858 static jvmtiError check_record_attribute(InstanceKlass* the_class, InstanceKlass* scratch_class) { 859 // Get lists of record components. 860 Array<RecordComponent*>* the_record = the_class->record_components(); 861 Array<RecordComponent*>* scr_record = scratch_class->record_components(); 862 bool the_record_exists = the_record != nullptr; 863 bool scr_record_exists = scr_record != nullptr; 864 865 if (the_record_exists && scr_record_exists) { 866 int the_num_components = the_record->length(); 867 int scr_num_components = scr_record->length(); 868 if (the_num_components != scr_num_components) { 869 log_info(redefine, class, record) 870 ("redefined class %s attribute change error: Record num_components=%d changed to num_components=%d", 871 the_class->external_name(), the_num_components, scr_num_components); 872 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 873 } 874 875 // Compare each field in each record component. 876 ConstantPool* the_cp = the_class->constants(); 877 ConstantPool* scr_cp = scratch_class->constants(); 878 for (int x = 0; x < the_num_components; x++) { 879 RecordComponent* the_component = the_record->at(x); 880 RecordComponent* scr_component = scr_record->at(x); 881 const Symbol* const the_name = the_cp->symbol_at(the_component->name_index()); 882 const Symbol* const scr_name = scr_cp->symbol_at(scr_component->name_index()); 883 const Symbol* const the_descr = the_cp->symbol_at(the_component->descriptor_index()); 884 const Symbol* const scr_descr = scr_cp->symbol_at(scr_component->descriptor_index()); 885 if (the_name != scr_name || the_descr != scr_descr) { 886 log_info(redefine, class, record) 887 ("redefined class %s attribute change error: Record name_index, descriptor_index, and/or attributes_count changed", 888 the_class->external_name()); 889 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 890 } 891 892 int the_gen_sig = the_component->generic_signature_index(); 893 int scr_gen_sig = scr_component->generic_signature_index(); 894 const Symbol* const the_gen_sig_sym = (the_gen_sig == 0 ? nullptr : 895 the_cp->symbol_at(the_component->generic_signature_index())); 896 const Symbol* const scr_gen_sig_sym = (scr_gen_sig == 0 ? nullptr : 897 scr_cp->symbol_at(scr_component->generic_signature_index())); 898 if (the_gen_sig_sym != scr_gen_sig_sym) { 899 log_info(redefine, class, record) 900 ("redefined class %s attribute change error: Record generic_signature attribute changed", 901 the_class->external_name()); 902 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 903 } 904 905 // It's okay if a record component's annotations were changed. 906 } 907 908 } else if (the_record_exists ^ scr_record_exists) { 909 const char* action_str = (the_record_exists) ? "removed" : "added"; 910 log_info(redefine, class, record) 911 ("redefined class %s attribute change error: Record attribute %s", 912 the_class->external_name(), action_str); 913 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 914 } 915 916 return JVMTI_ERROR_NONE; 917 } 918 919 920 static jvmtiError check_permitted_subclasses_attribute(InstanceKlass* the_class, 921 InstanceKlass* scratch_class) { 922 Thread* thread = Thread::current(); 923 ResourceMark rm(thread); 924 925 // Check whether the class PermittedSubclasses attribute has been changed. 926 return check_attribute_arrays("PermittedSubclasses", 927 the_class, scratch_class, 928 the_class->permitted_subclasses(), 929 scratch_class->permitted_subclasses()); 930 } 931 932 static bool can_add_or_delete(Method* m) { 933 // Compatibility mode 934 return (AllowRedefinitionToAddDeleteMethods && 935 (m->is_private() && (m->is_static() || m->is_final()))); 936 } 937 938 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions( 939 InstanceKlass* the_class, 940 InstanceKlass* scratch_class) { 941 int i; 942 943 // Check superclasses, or rather their names, since superclasses themselves can be 944 // requested to replace. 945 // Check for null superclass first since this might be java.lang.Object 946 if (the_class->super() != scratch_class->super() && 947 (the_class->super() == nullptr || scratch_class->super() == nullptr || 948 the_class->super()->name() != 949 scratch_class->super()->name())) { 950 log_info(redefine, class, normalize) 951 ("redefined class %s superclass change error: superclass changed from %s to %s.", 952 the_class->external_name(), 953 the_class->super() == nullptr ? "null" : the_class->super()->external_name(), 954 scratch_class->super() == nullptr ? "null" : scratch_class->super()->external_name()); 955 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 956 } 957 958 // Check if the number, names and order of directly implemented interfaces are the same. 959 // I think in principle we should just check if the sets of names of directly implemented 960 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the 961 // .java file, also changes in .class file) should not matter. However, comparing sets is 962 // technically a bit more difficult, and, more importantly, I am not sure at present that the 963 // order of interfaces does not matter on the implementation level, i.e. that the VM does not 964 // rely on it somewhere. 965 Array<InstanceKlass*>* k_interfaces = the_class->local_interfaces(); 966 Array<InstanceKlass*>* k_new_interfaces = scratch_class->local_interfaces(); 967 int n_intfs = k_interfaces->length(); 968 if (n_intfs != k_new_interfaces->length()) { 969 log_info(redefine, class, normalize) 970 ("redefined class %s interfaces change error: number of implemented interfaces changed from %d to %d.", 971 the_class->external_name(), n_intfs, k_new_interfaces->length()); 972 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 973 } 974 for (i = 0; i < n_intfs; i++) { 975 if (k_interfaces->at(i)->name() != 976 k_new_interfaces->at(i)->name()) { 977 log_info(redefine, class, normalize) 978 ("redefined class %s interfaces change error: interface changed from %s to %s.", 979 the_class->external_name(), 980 k_interfaces->at(i)->external_name(), k_new_interfaces->at(i)->external_name()); 981 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 982 } 983 } 984 985 // Check whether class is in the error init state. 986 if (the_class->is_in_error_state()) { 987 log_info(redefine, class, normalize) 988 ("redefined class %s is in error init state.", the_class->external_name()); 989 // TBD #5057930: special error code is needed in 1.6 990 return JVMTI_ERROR_INVALID_CLASS; 991 } 992 993 // Check whether the nest-related attributes have been changed. 994 jvmtiError err = check_nest_attributes(the_class, scratch_class); 995 if (err != JVMTI_ERROR_NONE) { 996 return err; 997 } 998 999 // Check whether the Record attribute has been changed. 1000 err = check_record_attribute(the_class, scratch_class); 1001 if (err != JVMTI_ERROR_NONE) { 1002 return err; 1003 } 1004 1005 // Check whether the PermittedSubclasses attribute has been changed. 1006 err = check_permitted_subclasses_attribute(the_class, scratch_class); 1007 if (err != JVMTI_ERROR_NONE) { 1008 return err; 1009 } 1010 1011 // Check whether class modifiers are the same. 1012 u2 old_flags = the_class->access_flags().as_class_flags(); 1013 u2 new_flags = scratch_class->access_flags().as_class_flags(); 1014 if (old_flags != new_flags) { 1015 log_info(redefine, class, normalize) 1016 ("redefined class %s modifiers change error: modifiers changed from %d to %d.", 1017 the_class->external_name(), old_flags, new_flags); 1018 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED; 1019 } 1020 1021 // Check if the number, names, types and order of fields declared in these classes 1022 // are the same. 1023 JavaFieldStream old_fs(the_class); 1024 JavaFieldStream new_fs(scratch_class); 1025 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) { 1026 // name and signature 1027 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index()); 1028 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index()); 1029 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index()); 1030 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index()); 1031 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) { 1032 log_info(redefine, class, normalize) 1033 ("redefined class %s fields change error: field %s %s changed to %s %s.", 1034 the_class->external_name(), 1035 sig_sym1->as_C_string(), name_sym1->as_C_string(), 1036 sig_sym2->as_C_string(), name_sym2->as_C_string()); 1037 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 1038 } 1039 // offset 1040 if (old_fs.offset() != new_fs.offset()) { 1041 log_info(redefine, class, normalize) 1042 ("redefined class %s field %s change error: offset changed from %d to %d.", 1043 the_class->external_name(), name_sym2->as_C_string(), old_fs.offset(), new_fs.offset()); 1044 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 1045 } 1046 // access 1047 old_flags = old_fs.access_flags().as_field_flags(); 1048 new_flags = new_fs.access_flags().as_field_flags(); 1049 if (old_flags != new_flags) { 1050 log_info(redefine, class, normalize) 1051 ("redefined class %s field %s change error: modifiers changed from %d to %d.", 1052 the_class->external_name(), name_sym2->as_C_string(), old_flags, new_flags); 1053 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 1054 } 1055 } 1056 1057 // If both streams aren't done then we have a differing number of 1058 // fields. 1059 if (!old_fs.done() || !new_fs.done()) { 1060 const char* action = old_fs.done() ? "added" : "deleted"; 1061 log_info(redefine, class, normalize) 1062 ("redefined class %s fields change error: some fields were %s.", 1063 the_class->external_name(), action); 1064 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 1065 } 1066 1067 // Do a parallel walk through the old and new methods. Detect 1068 // cases where they match (exist in both), have been added in 1069 // the new methods, or have been deleted (exist only in the 1070 // old methods). The class file parser places methods in order 1071 // by method name, but does not order overloaded methods by 1072 // signature. In order to determine what fate befell the methods, 1073 // this code places the overloaded new methods that have matching 1074 // old methods in the same order as the old methods and places 1075 // new overloaded methods at the end of overloaded methods of 1076 // that name. The code for this order normalization is adapted 1077 // from the algorithm used in InstanceKlass::find_method(). 1078 // Since we are swapping out of order entries as we find them, 1079 // we only have to search forward through the overloaded methods. 1080 // Methods which are added and have the same name as an existing 1081 // method (but different signature) will be put at the end of 1082 // the methods with that name, and the name mismatch code will 1083 // handle them. 1084 Array<Method*>* k_old_methods(the_class->methods()); 1085 Array<Method*>* k_new_methods(scratch_class->methods()); 1086 int n_old_methods = k_old_methods->length(); 1087 int n_new_methods = k_new_methods->length(); 1088 Thread* thread = Thread::current(); 1089 1090 int ni = 0; 1091 int oi = 0; 1092 while (true) { 1093 Method* k_old_method; 1094 Method* k_new_method; 1095 enum { matched, added, deleted, undetermined } method_was = undetermined; 1096 1097 if (oi >= n_old_methods) { 1098 if (ni >= n_new_methods) { 1099 break; // we've looked at everything, done 1100 } 1101 // New method at the end 1102 k_new_method = k_new_methods->at(ni); 1103 method_was = added; 1104 } else if (ni >= n_new_methods) { 1105 // Old method, at the end, is deleted 1106 k_old_method = k_old_methods->at(oi); 1107 method_was = deleted; 1108 } else { 1109 // There are more methods in both the old and new lists 1110 k_old_method = k_old_methods->at(oi); 1111 k_new_method = k_new_methods->at(ni); 1112 if (k_old_method->name() != k_new_method->name()) { 1113 // Methods are sorted by method name, so a mismatch means added 1114 // or deleted 1115 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) { 1116 method_was = added; 1117 } else { 1118 method_was = deleted; 1119 } 1120 } else if (k_old_method->signature() == k_new_method->signature()) { 1121 // Both the name and signature match 1122 method_was = matched; 1123 } else { 1124 // The name matches, but the signature doesn't, which means we have to 1125 // search forward through the new overloaded methods. 1126 int nj; // outside the loop for post-loop check 1127 for (nj = ni + 1; nj < n_new_methods; nj++) { 1128 Method* m = k_new_methods->at(nj); 1129 if (k_old_method->name() != m->name()) { 1130 // reached another method name so no more overloaded methods 1131 method_was = deleted; 1132 break; 1133 } 1134 if (k_old_method->signature() == m->signature()) { 1135 // found a match so swap the methods 1136 k_new_methods->at_put(ni, m); 1137 k_new_methods->at_put(nj, k_new_method); 1138 k_new_method = m; 1139 method_was = matched; 1140 break; 1141 } 1142 } 1143 1144 if (nj >= n_new_methods) { 1145 // reached the end without a match; so method was deleted 1146 method_was = deleted; 1147 } 1148 } 1149 } 1150 1151 switch (method_was) { 1152 case matched: 1153 // methods match, be sure modifiers do too 1154 old_flags = k_old_method->access_flags().as_method_flags(); 1155 new_flags = k_new_method->access_flags().as_method_flags(); 1156 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) { 1157 log_info(redefine, class, normalize) 1158 ("redefined class %s method %s modifiers error: modifiers changed from %d to %d", 1159 the_class->external_name(), k_old_method->name_and_sig_as_C_string(), old_flags, new_flags); 1160 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED; 1161 } 1162 { 1163 u2 new_num = k_new_method->method_idnum(); 1164 u2 old_num = k_old_method->method_idnum(); 1165 if (new_num != old_num) { 1166 Method* idnum_owner = scratch_class->method_with_idnum(old_num); 1167 if (idnum_owner != nullptr) { 1168 // There is already a method assigned this idnum -- switch them 1169 // Take current and original idnum from the new_method 1170 idnum_owner->set_method_idnum(new_num); 1171 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum()); 1172 } 1173 // Take current and original idnum from the old_method 1174 k_new_method->set_method_idnum(old_num); 1175 k_new_method->set_orig_method_idnum(k_old_method->orig_method_idnum()); 1176 if (thread->has_pending_exception()) { 1177 return JVMTI_ERROR_OUT_OF_MEMORY; 1178 } 1179 } 1180 } 1181 log_trace(redefine, class, normalize) 1182 ("Method matched: new: %s [%d] == old: %s [%d]", 1183 k_new_method->name_and_sig_as_C_string(), ni, k_old_method->name_and_sig_as_C_string(), oi); 1184 // advance to next pair of methods 1185 ++oi; 1186 ++ni; 1187 break; 1188 case added: 1189 // method added, see if it is OK 1190 if (!can_add_or_delete(k_new_method)) { 1191 log_info(redefine, class, normalize) 1192 ("redefined class %s methods error: added method: %s [%d]", 1193 the_class->external_name(), k_new_method->name_and_sig_as_C_string(), ni); 1194 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED; 1195 } 1196 { 1197 u2 num = the_class->next_method_idnum(); 1198 if (num == ConstMethod::UNSET_IDNUM) { 1199 // cannot add any more methods 1200 log_info(redefine, class, normalize) 1201 ("redefined class %s methods error: can't create ID for new method %s [%d]", 1202 the_class->external_name(), k_new_method->name_and_sig_as_C_string(), ni); 1203 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED; 1204 } 1205 u2 new_num = k_new_method->method_idnum(); 1206 Method* idnum_owner = scratch_class->method_with_idnum(num); 1207 if (idnum_owner != nullptr) { 1208 // There is already a method assigned this idnum -- switch them 1209 // Take current and original idnum from the new_method 1210 idnum_owner->set_method_idnum(new_num); 1211 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum()); 1212 } 1213 k_new_method->set_method_idnum(num); 1214 k_new_method->set_orig_method_idnum(num); 1215 if (thread->has_pending_exception()) { 1216 return JVMTI_ERROR_OUT_OF_MEMORY; 1217 } 1218 } 1219 log_trace(redefine, class, normalize) 1220 ("Method added: new: %s [%d]", k_new_method->name_and_sig_as_C_string(), ni); 1221 ++ni; // advance to next new method 1222 break; 1223 case deleted: 1224 // method deleted, see if it is OK 1225 if (!can_add_or_delete(k_old_method)) { 1226 log_info(redefine, class, normalize) 1227 ("redefined class %s methods error: deleted method %s [%d]", 1228 the_class->external_name(), k_old_method->name_and_sig_as_C_string(), oi); 1229 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED; 1230 } 1231 log_trace(redefine, class, normalize) 1232 ("Method deleted: old: %s [%d]", k_old_method->name_and_sig_as_C_string(), oi); 1233 ++oi; // advance to next old method 1234 break; 1235 default: 1236 ShouldNotReachHere(); 1237 } 1238 } 1239 1240 return JVMTI_ERROR_NONE; 1241 } 1242 1243 1244 // Find new constant pool index value for old constant pool index value 1245 // by searching the index map. Returns zero (0) if there is no mapped 1246 // value for the old constant pool index. 1247 u2 VM_RedefineClasses::find_new_index(int old_index) { 1248 if (_index_map_count == 0) { 1249 // map is empty so nothing can be found 1250 return 0; 1251 } 1252 1253 if (old_index < 1 || old_index >= _index_map_p->length()) { 1254 // The old_index is out of range so it is not mapped. This should 1255 // not happen in regular constant pool merging use, but it can 1256 // happen if a corrupt annotation is processed. 1257 return 0; 1258 } 1259 1260 int value = _index_map_p->at(old_index); 1261 if (value == -1) { 1262 // the old_index is not mapped 1263 return 0; 1264 } 1265 1266 // constant pool indices are u2, unless the merged constant pool overflows which 1267 // we don't check for. 1268 return checked_cast<u2>(value); 1269 } // end find_new_index() 1270 1271 1272 // Find new bootstrap specifier index value for old bootstrap specifier index 1273 // value by searching the index map. Returns unused index (-1) if there is 1274 // no mapped value for the old bootstrap specifier index. 1275 int VM_RedefineClasses::find_new_operand_index(int old_index) { 1276 if (_operands_index_map_count == 0) { 1277 // map is empty so nothing can be found 1278 return -1; 1279 } 1280 1281 if (old_index == -1 || old_index >= _operands_index_map_p->length()) { 1282 // The old_index is out of range so it is not mapped. 1283 // This should not happen in regular constant pool merging use. 1284 return -1; 1285 } 1286 1287 int value = _operands_index_map_p->at(old_index); 1288 if (value == -1) { 1289 // the old_index is not mapped 1290 return -1; 1291 } 1292 1293 return value; 1294 } // end find_new_operand_index() 1295 1296 1297 // The bug 6214132 caused the verification to fail. 1298 // 1. What's done in RedefineClasses() before verification: 1299 // a) A reference to the class being redefined (_the_class) and a 1300 // reference to new version of the class (_scratch_class) are 1301 // saved here for use during the bytecode verification phase of 1302 // RedefineClasses. 1303 // b) The _java_mirror field from _the_class is copied to the 1304 // _java_mirror field in _scratch_class. This means that a jclass 1305 // returned for _the_class or _scratch_class will refer to the 1306 // same Java mirror. The verifier will see the "one true mirror" 1307 // for the class being verified. 1308 // 2. See comments in JvmtiThreadState for what is done during verification. 1309 1310 class RedefineVerifyMark : public StackObj { 1311 private: 1312 JvmtiThreadState* _state; 1313 Klass* _scratch_class; 1314 OopHandle _scratch_mirror; 1315 1316 public: 1317 1318 RedefineVerifyMark(Klass* the_class, Klass* scratch_class, 1319 JvmtiThreadState* state) : _state(state), _scratch_class(scratch_class) 1320 { 1321 _state->set_class_versions_map(the_class, scratch_class); 1322 _scratch_mirror = the_class->java_mirror_handle(); // this is a copy that is swapped 1323 _scratch_class->swap_java_mirror_handle(_scratch_mirror); 1324 } 1325 1326 ~RedefineVerifyMark() { 1327 // Restore the scratch class's mirror, so when scratch_class is removed 1328 // the correct mirror pointing to it can be cleared. 1329 _scratch_class->swap_java_mirror_handle(_scratch_mirror); 1330 _state->clear_class_versions_map(); 1331 } 1332 }; 1333 1334 1335 jvmtiError VM_RedefineClasses::load_new_class_versions() { 1336 1337 // For consistency allocate memory using os::malloc wrapper. 1338 _scratch_classes = (InstanceKlass**) 1339 os::malloc(sizeof(InstanceKlass*) * _class_count, mtClass); 1340 if (_scratch_classes == nullptr) { 1341 return JVMTI_ERROR_OUT_OF_MEMORY; 1342 } 1343 // Zero initialize the _scratch_classes array. 1344 for (int i = 0; i < _class_count; i++) { 1345 _scratch_classes[i] = nullptr; 1346 } 1347 1348 JavaThread* current = JavaThread::current(); 1349 ResourceMark rm(current); 1350 1351 JvmtiThreadState *state = JvmtiThreadState::state_for(current); 1352 // state can only be null if the current thread is exiting which 1353 // should not happen since we're trying to do a RedefineClasses 1354 guarantee(state != nullptr, "exiting thread calling load_new_class_versions"); 1355 for (int i = 0; i < _class_count; i++) { 1356 // Create HandleMark so that any handles created while loading new class 1357 // versions are deleted. Constant pools are deallocated while merging 1358 // constant pools 1359 HandleMark hm(current); 1360 InstanceKlass* the_class = get_ik(_class_defs[i].klass); 1361 size_t avail_mem = 0; 1362 // Return value ignored - defaulting to 0 on failure. 1363 (void)os::available_memory(avail_mem); 1364 log_debug(redefine, class, load) 1365 ("loading name=%s kind=%d (avail_mem=%zuK)", 1366 the_class->external_name(), _class_load_kind, avail_mem >> 10); 1367 1368 ClassFileStream st((u1*)_class_defs[i].class_bytes, 1369 _class_defs[i].class_byte_count, 1370 "__VM_RedefineClasses__"); 1371 1372 // Set redefined class handle in JvmtiThreadState class. 1373 // This redefined class is sent to agent event handler for class file 1374 // load hook event. 1375 state->set_class_being_redefined(the_class, _class_load_kind); 1376 1377 JavaThread* THREAD = current; // For exception macros. 1378 ExceptionMark em(THREAD); 1379 Handle protection_domain(THREAD, the_class->protection_domain()); 1380 ClassLoadInfo cl_info(protection_domain); 1381 // Parse and create a class from the bytes, but this class isn't added 1382 // to the dictionary, so do not call resolve_from_stream. 1383 InstanceKlass* scratch_class = KlassFactory::create_from_stream(&st, 1384 the_class->name(), 1385 the_class->class_loader_data(), 1386 cl_info, 1387 THREAD); 1388 1389 // Clear class_being_redefined just to be sure. 1390 state->clear_class_being_redefined(); 1391 1392 // TODO: if this is retransform, and nothing changed we can skip it 1393 1394 // Need to clean up allocated InstanceKlass if there's an error so assign 1395 // the result here. Caller deallocates all the scratch classes in case of 1396 // an error. 1397 _scratch_classes[i] = scratch_class; 1398 1399 if (HAS_PENDING_EXCEPTION) { 1400 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1401 log_info(redefine, class, load, exceptions)("create_from_stream exception: '%s'", ex_name->as_C_string()); 1402 CLEAR_PENDING_EXCEPTION; 1403 1404 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) { 1405 return JVMTI_ERROR_UNSUPPORTED_VERSION; 1406 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) { 1407 return JVMTI_ERROR_INVALID_CLASS_FORMAT; 1408 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) { 1409 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION; 1410 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) { 1411 // The message will be "XXX (wrong name: YYY)" 1412 return JVMTI_ERROR_NAMES_DONT_MATCH; 1413 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1414 return JVMTI_ERROR_OUT_OF_MEMORY; 1415 } else { // Just in case more exceptions can be thrown.. 1416 return JVMTI_ERROR_FAILS_VERIFICATION; 1417 } 1418 } 1419 1420 // Ensure class is linked before redefine 1421 if (!the_class->is_linked()) { 1422 the_class->link_class(THREAD); 1423 if (HAS_PENDING_EXCEPTION) { 1424 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1425 oop message = java_lang_Throwable::message(PENDING_EXCEPTION); 1426 if (message != nullptr) { 1427 char* ex_msg = java_lang_String::as_utf8_string(message); 1428 log_info(redefine, class, load, exceptions)("link_class exception: '%s %s'", 1429 ex_name->as_C_string(), ex_msg); 1430 } else { 1431 log_info(redefine, class, load, exceptions)("link_class exception: '%s'", 1432 ex_name->as_C_string()); 1433 } 1434 CLEAR_PENDING_EXCEPTION; 1435 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1436 return JVMTI_ERROR_OUT_OF_MEMORY; 1437 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) { 1438 return JVMTI_ERROR_INVALID_CLASS; 1439 } else { 1440 return JVMTI_ERROR_INTERNAL; 1441 } 1442 } 1443 } 1444 1445 // Do the validity checks in compare_and_normalize_class_versions() 1446 // before verifying the byte codes. By doing these checks first, we 1447 // limit the number of functions that require redirection from 1448 // the_class to scratch_class. In particular, we don't have to 1449 // modify JNI GetSuperclass() and thus won't change its performance. 1450 jvmtiError res = compare_and_normalize_class_versions(the_class, 1451 scratch_class); 1452 if (res != JVMTI_ERROR_NONE) { 1453 return res; 1454 } 1455 1456 // verify what the caller passed us 1457 { 1458 // The bug 6214132 caused the verification to fail. 1459 // Information about the_class and scratch_class is temporarily 1460 // recorded into jvmtiThreadState. This data is used to redirect 1461 // the_class to scratch_class in the JVM_* functions called by the 1462 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed 1463 // description. 1464 RedefineVerifyMark rvm(the_class, scratch_class, state); 1465 Verifier::verify(scratch_class, true, THREAD); 1466 } 1467 1468 if (HAS_PENDING_EXCEPTION) { 1469 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1470 log_info(redefine, class, load, exceptions)("verify_byte_codes exception: '%s'", ex_name->as_C_string()); 1471 CLEAR_PENDING_EXCEPTION; 1472 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1473 return JVMTI_ERROR_OUT_OF_MEMORY; 1474 } else { 1475 // tell the caller the bytecodes are bad 1476 return JVMTI_ERROR_FAILS_VERIFICATION; 1477 } 1478 } 1479 1480 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD); 1481 if (HAS_PENDING_EXCEPTION) { 1482 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1483 log_info(redefine, class, load, exceptions)("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string()); 1484 CLEAR_PENDING_EXCEPTION; 1485 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1486 return JVMTI_ERROR_OUT_OF_MEMORY; 1487 } else { 1488 return JVMTI_ERROR_INTERNAL; 1489 } 1490 } 1491 1492 #ifdef ASSERT 1493 { 1494 // verify what we have done during constant pool merging 1495 { 1496 RedefineVerifyMark rvm(the_class, scratch_class, state); 1497 Verifier::verify(scratch_class, true, THREAD); 1498 } 1499 1500 if (HAS_PENDING_EXCEPTION) { 1501 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1502 log_info(redefine, class, load, exceptions) 1503 ("verify_byte_codes post merge-CP exception: '%s'", ex_name->as_C_string()); 1504 CLEAR_PENDING_EXCEPTION; 1505 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1506 return JVMTI_ERROR_OUT_OF_MEMORY; 1507 } else { 1508 // tell the caller that constant pool merging screwed up 1509 return JVMTI_ERROR_INTERNAL; 1510 } 1511 } 1512 } 1513 #endif // ASSERT 1514 1515 Rewriter::rewrite(scratch_class, THREAD); 1516 if (!HAS_PENDING_EXCEPTION) { 1517 scratch_class->link_methods(THREAD); 1518 } 1519 if (HAS_PENDING_EXCEPTION) { 1520 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1521 log_info(redefine, class, load, exceptions) 1522 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string()); 1523 CLEAR_PENDING_EXCEPTION; 1524 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1525 return JVMTI_ERROR_OUT_OF_MEMORY; 1526 } else { 1527 return JVMTI_ERROR_INTERNAL; 1528 } 1529 } 1530 // Return value ignored - defaulting to 0 on failure. 1531 (void)os::available_memory(avail_mem); 1532 log_debug(redefine, class, load) 1533 ("loaded name=%s (avail_mem=%zuK)", the_class->external_name(), avail_mem >> 10); 1534 } 1535 1536 return JVMTI_ERROR_NONE; 1537 } 1538 1539 1540 // Map old_index to new_index as needed. scratch_cp is only needed 1541 // for log calls. 1542 void VM_RedefineClasses::map_index(const constantPoolHandle& scratch_cp, 1543 int old_index, int new_index) { 1544 if (find_new_index(old_index) != 0) { 1545 // old_index is already mapped 1546 return; 1547 } 1548 1549 if (old_index == new_index) { 1550 // no mapping is needed 1551 return; 1552 } 1553 1554 _index_map_p->at_put(old_index, new_index); 1555 _index_map_count++; 1556 1557 log_trace(redefine, class, constantpool) 1558 ("mapped tag %d at index %d to %d", scratch_cp->tag_at(old_index).value(), old_index, new_index); 1559 } // end map_index() 1560 1561 1562 // Map old_index to new_index as needed. 1563 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) { 1564 if (find_new_operand_index(old_index) != -1) { 1565 // old_index is already mapped 1566 return; 1567 } 1568 1569 if (old_index == new_index) { 1570 // no mapping is needed 1571 return; 1572 } 1573 1574 _operands_index_map_p->at_put(old_index, new_index); 1575 _operands_index_map_count++; 1576 1577 log_trace(redefine, class, constantpool)("mapped bootstrap specifier at index %d to %d", old_index, new_index); 1578 } // end map_index() 1579 1580 1581 // Merge old_cp and scratch_cp and return the results of the merge via 1582 // merge_cp_p. The number of entries in merge_cp_p is returned via 1583 // merge_cp_length_p. The entries in old_cp occupy the same locations 1584 // in merge_cp_p. Also creates a map of indices from entries in 1585 // scratch_cp to the corresponding entry in merge_cp_p. Index map 1586 // entries are only created for entries in scratch_cp that occupy a 1587 // different location in merged_cp_p. 1588 bool VM_RedefineClasses::merge_constant_pools(const constantPoolHandle& old_cp, 1589 const constantPoolHandle& scratch_cp, constantPoolHandle& merge_cp_p, 1590 int& merge_cp_length_p, TRAPS) { 1591 1592 // Worst case we need old_cp->length() + scratch_cp()->length(), 1593 // but the caller might be smart so make sure we have at least 1594 // the minimum. 1595 if (merge_cp_p->length() < old_cp->length()) { 1596 assert(false, "merge area too small"); 1597 return false; // robustness 1598 } 1599 1600 log_info(redefine, class, constantpool)("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(), scratch_cp->length()); 1601 1602 { 1603 // Pass 0: 1604 // The old_cp is copied to *merge_cp_p; this means that any code 1605 // using old_cp does not have to change. This work looks like a 1606 // perfect fit for ConstantPool*::copy_cp_to(), but we need to 1607 // handle one special case: 1608 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass 1609 // This will make verification happy. 1610 1611 int old_i; // index into old_cp 1612 1613 // index zero (0) is not used in constantPools 1614 for (old_i = 1; old_i < old_cp->length(); old_i++) { 1615 // leave debugging crumb 1616 jbyte old_tag = old_cp->tag_at(old_i).value(); 1617 switch (old_tag) { 1618 case JVM_CONSTANT_Class: 1619 case JVM_CONSTANT_UnresolvedClass: 1620 // revert the copy to JVM_CONSTANT_UnresolvedClass 1621 // May be resolving while calling this so do the same for 1622 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition) 1623 merge_cp_p->temp_unresolved_klass_at_put(old_i, 1624 old_cp->klass_name_index_at(old_i)); 1625 break; 1626 1627 case JVM_CONSTANT_Double: 1628 case JVM_CONSTANT_Long: 1629 // just copy the entry to merge_cp_p, but double and long take 1630 // two constant pool entries 1631 ConstantPool::copy_entry_to(old_cp, old_i, merge_cp_p, old_i); 1632 old_i++; 1633 break; 1634 1635 default: 1636 // just copy the entry to merge_cp_p 1637 ConstantPool::copy_entry_to(old_cp, old_i, merge_cp_p, old_i); 1638 break; 1639 } 1640 } // end for each old_cp entry 1641 1642 ConstantPool::copy_operands(old_cp, merge_cp_p, CHECK_false); 1643 merge_cp_p->extend_operands(scratch_cp, CHECK_false); 1644 1645 // We don't need to sanity check that *merge_cp_length_p is within 1646 // *merge_cp_p bounds since we have the minimum on-entry check above. 1647 merge_cp_length_p = old_i; 1648 } 1649 1650 // merge_cp_len should be the same as old_cp->length() at this point 1651 // so this trace message is really a "warm-and-breathing" message. 1652 log_debug(redefine, class, constantpool)("after pass 0: merge_cp_len=%d", merge_cp_length_p); 1653 1654 int scratch_i; // index into scratch_cp 1655 { 1656 // Pass 1a: 1657 // Compare scratch_cp entries to the old_cp entries that we have 1658 // already copied to *merge_cp_p. In this pass, we are eliminating 1659 // exact duplicates (matching entry at same index) so we only 1660 // compare entries in the common indice range. 1661 int increment = 1; 1662 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length()); 1663 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) { 1664 switch (scratch_cp->tag_at(scratch_i).value()) { 1665 case JVM_CONSTANT_Double: 1666 case JVM_CONSTANT_Long: 1667 // double and long take two constant pool entries 1668 increment = 2; 1669 break; 1670 1671 default: 1672 increment = 1; 1673 break; 1674 } 1675 1676 bool match = scratch_cp->compare_entry_to(scratch_i, merge_cp_p, scratch_i); 1677 if (match) { 1678 // found a match at the same index so nothing more to do 1679 continue; 1680 } 1681 1682 int found_i = scratch_cp->find_matching_entry(scratch_i, merge_cp_p); 1683 if (found_i != 0) { 1684 guarantee(found_i != scratch_i, 1685 "compare_entry_to() and find_matching_entry() do not agree"); 1686 1687 // Found a matching entry somewhere else in *merge_cp_p so 1688 // just need a mapping entry. 1689 map_index(scratch_cp, scratch_i, found_i); 1690 continue; 1691 } 1692 1693 // No match found so we have to append this entry and any unique 1694 // referenced entries to merge_cp_p. 1695 append_entry(scratch_cp, scratch_i, &merge_cp_p, &merge_cp_length_p); 1696 } 1697 } 1698 1699 log_debug(redefine, class, constantpool) 1700 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", 1701 merge_cp_length_p, scratch_i, _index_map_count); 1702 1703 if (scratch_i < scratch_cp->length()) { 1704 // Pass 1b: 1705 // old_cp is smaller than scratch_cp so there are entries in 1706 // scratch_cp that we have not yet processed. We take care of 1707 // those now. 1708 int increment = 1; 1709 for (; scratch_i < scratch_cp->length(); scratch_i += increment) { 1710 switch (scratch_cp->tag_at(scratch_i).value()) { 1711 case JVM_CONSTANT_Double: 1712 case JVM_CONSTANT_Long: 1713 // double and long take two constant pool entries 1714 increment = 2; 1715 break; 1716 1717 default: 1718 increment = 1; 1719 break; 1720 } 1721 1722 int found_i = 1723 scratch_cp->find_matching_entry(scratch_i, merge_cp_p); 1724 if (found_i != 0) { 1725 // Found a matching entry somewhere else in merge_cp_p so 1726 // just need a mapping entry. 1727 map_index(scratch_cp, scratch_i, found_i); 1728 continue; 1729 } 1730 1731 // No match found so we have to append this entry and any unique 1732 // referenced entries to merge_cp_p. 1733 append_entry(scratch_cp, scratch_i, &merge_cp_p, &merge_cp_length_p); 1734 } 1735 1736 log_debug(redefine, class, constantpool) 1737 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", 1738 merge_cp_length_p, scratch_i, _index_map_count); 1739 } 1740 finalize_operands_merge(merge_cp_p, CHECK_false); 1741 1742 return true; 1743 } // end merge_constant_pools() 1744 1745 1746 // Scoped object to clean up the constant pool(s) created for merging 1747 class MergeCPCleaner { 1748 ClassLoaderData* _loader_data; 1749 ConstantPool* _cp; 1750 ConstantPool* _scratch_cp; 1751 public: 1752 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) : 1753 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(nullptr) {} 1754 ~MergeCPCleaner() { 1755 _loader_data->add_to_deallocate_list(_cp); 1756 if (_scratch_cp != nullptr) { 1757 _loader_data->add_to_deallocate_list(_scratch_cp); 1758 } 1759 } 1760 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; } 1761 }; 1762 1763 // Merge constant pools between the_class and scratch_class and 1764 // potentially rewrite bytecodes in scratch_class to use the merged 1765 // constant pool. 1766 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite( 1767 InstanceKlass* the_class, InstanceKlass* scratch_class, 1768 TRAPS) { 1769 // worst case merged constant pool length is old and new combined 1770 int merge_cp_length = the_class->constants()->length() 1771 + scratch_class->constants()->length(); 1772 1773 // Constant pools are not easily reused so we allocate a new one 1774 // each time. 1775 // merge_cp is created unsafe for concurrent GC processing. It 1776 // should be marked safe before discarding it. Even though 1777 // garbage, if it crosses a card boundary, it may be scanned 1778 // in order to find the start of the first complete object on the card. 1779 ClassLoaderData* loader_data = the_class->class_loader_data(); 1780 ConstantPool* merge_cp_oop = 1781 ConstantPool::allocate(loader_data, 1782 merge_cp_length, 1783 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1784 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop); 1785 1786 HandleMark hm(THREAD); // make sure handles are cleared before 1787 // MergeCPCleaner clears out merge_cp_oop 1788 constantPoolHandle merge_cp(THREAD, merge_cp_oop); 1789 1790 // Get constants() from the old class because it could have been rewritten 1791 // while we were at a safepoint allocating a new constant pool. 1792 constantPoolHandle old_cp(THREAD, the_class->constants()); 1793 constantPoolHandle scratch_cp(THREAD, scratch_class->constants()); 1794 1795 // If the length changed, the class was redefined out from under us. Return 1796 // an error. 1797 if (merge_cp_length != the_class->constants()->length() 1798 + scratch_class->constants()->length()) { 1799 return JVMTI_ERROR_INTERNAL; 1800 } 1801 1802 // Update the version number of the constant pools (may keep scratch_cp) 1803 merge_cp->increment_and_save_version(old_cp->version()); 1804 scratch_cp->increment_and_save_version(old_cp->version()); 1805 1806 ResourceMark rm(THREAD); 1807 _index_map_count = 0; 1808 _index_map_p = new intArray(scratch_cp->length(), scratch_cp->length(), -1); 1809 1810 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands()); 1811 _operands_index_map_count = 0; 1812 int operands_index_map_len = ConstantPool::operand_array_length(scratch_cp->operands()); 1813 _operands_index_map_p = new intArray(operands_index_map_len, operands_index_map_len, -1); 1814 1815 // reference to the cp holder is needed for copy_operands() 1816 merge_cp->set_pool_holder(scratch_class); 1817 bool result = merge_constant_pools(old_cp, scratch_cp, merge_cp, 1818 merge_cp_length, THREAD); 1819 merge_cp->set_pool_holder(nullptr); 1820 1821 if (!result) { 1822 // The merge can fail due to memory allocation failure or due 1823 // to robustness checks. 1824 return JVMTI_ERROR_INTERNAL; 1825 } 1826 1827 // ensure merged constant pool size does not overflow u2 1828 if (merge_cp_length > 0xFFFF) { 1829 log_warning(redefine, class, constantpool)("Merged constant pool overflow: %d entries", merge_cp_length); 1830 return JVMTI_ERROR_INTERNAL; 1831 } 1832 1833 // Set dynamic constants attribute from the original CP. 1834 if (old_cp->has_dynamic_constant()) { 1835 scratch_cp->set_has_dynamic_constant(); 1836 } 1837 1838 log_info(redefine, class, constantpool)("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count); 1839 1840 if (_index_map_count == 0) { 1841 // there is nothing to map between the new and merged constant pools 1842 1843 // Copy attributes from scratch_cp to merge_cp 1844 merge_cp->copy_fields(scratch_cp()); 1845 1846 if (old_cp->length() == scratch_cp->length()) { 1847 // The old and new constant pools are the same length and the 1848 // index map is empty. This means that the three constant pools 1849 // are equivalent (but not the same). Unfortunately, the new 1850 // constant pool has not gone through link resolution nor have 1851 // the new class bytecodes gone through constant pool cache 1852 // rewriting so we can't use the old constant pool with the new 1853 // class. 1854 1855 // toss the merged constant pool at return 1856 } else if (old_cp->length() < scratch_cp->length()) { 1857 // The old constant pool has fewer entries than the new constant 1858 // pool and the index map is empty. This means the new constant 1859 // pool is a superset of the old constant pool. However, the old 1860 // class bytecodes have already gone through constant pool cache 1861 // rewriting so we can't use the new constant pool with the old 1862 // class. 1863 1864 // toss the merged constant pool at return 1865 } else { 1866 // The old constant pool has more entries than the new constant 1867 // pool and the index map is empty. This means that both the old 1868 // and merged constant pools are supersets of the new constant 1869 // pool. 1870 1871 // Replace the new constant pool with a shrunken copy of the 1872 // merged constant pool 1873 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, 1874 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1875 // The new constant pool replaces scratch_cp so have cleaner clean it up. 1876 // It can't be cleaned up while there are handles to it. 1877 cp_cleaner.add_scratch_cp(scratch_cp()); 1878 } 1879 } else { 1880 if (log_is_enabled(Trace, redefine, class, constantpool)) { 1881 // don't want to loop unless we are tracing 1882 int count = 0; 1883 for (int i = 1; i < _index_map_p->length(); i++) { 1884 int value = _index_map_p->at(i); 1885 1886 if (value != -1) { 1887 log_trace(redefine, class, constantpool)("index_map[%d]: old=%d new=%d", count, i, value); 1888 count++; 1889 } 1890 } 1891 } 1892 1893 // We have entries mapped between the new and merged constant pools 1894 // so we have to rewrite some constant pool references. 1895 if (!rewrite_cp_refs(scratch_class)) { 1896 return JVMTI_ERROR_INTERNAL; 1897 } 1898 1899 // Copy attributes from scratch_cp to merge_cp (should be done after rewrite_cp_refs()) 1900 merge_cp->copy_fields(scratch_cp()); 1901 1902 // Replace the new constant pool with a shrunken copy of the 1903 // merged constant pool so now the rewritten bytecodes have 1904 // valid references; the previous new constant pool will get 1905 // GCed. 1906 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, 1907 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1908 // The new constant pool replaces scratch_cp so have cleaner clean it up. 1909 // It can't be cleaned up while there are handles to it. 1910 cp_cleaner.add_scratch_cp(scratch_cp()); 1911 } 1912 1913 return JVMTI_ERROR_NONE; 1914 } // end merge_cp_and_rewrite() 1915 1916 1917 // Rewrite constant pool references in klass scratch_class. 1918 bool VM_RedefineClasses::rewrite_cp_refs(InstanceKlass* scratch_class) { 1919 1920 // rewrite constant pool references in the nest attributes: 1921 if (!rewrite_cp_refs_in_nest_attributes(scratch_class)) { 1922 // propagate failure back to caller 1923 return false; 1924 } 1925 1926 // rewrite constant pool references in the Record attribute: 1927 if (!rewrite_cp_refs_in_record_attribute(scratch_class)) { 1928 // propagate failure back to caller 1929 return false; 1930 } 1931 1932 // rewrite constant pool references in the PermittedSubclasses attribute: 1933 if (!rewrite_cp_refs_in_permitted_subclasses_attribute(scratch_class)) { 1934 // propagate failure back to caller 1935 return false; 1936 } 1937 1938 // rewrite constant pool references in the methods: 1939 if (!rewrite_cp_refs_in_methods(scratch_class)) { 1940 // propagate failure back to caller 1941 return false; 1942 } 1943 1944 // rewrite constant pool references in the class_annotations: 1945 if (!rewrite_cp_refs_in_class_annotations(scratch_class)) { 1946 // propagate failure back to caller 1947 return false; 1948 } 1949 1950 // rewrite constant pool references in the fields_annotations: 1951 if (!rewrite_cp_refs_in_fields_annotations(scratch_class)) { 1952 // propagate failure back to caller 1953 return false; 1954 } 1955 1956 // rewrite constant pool references in the methods_annotations: 1957 if (!rewrite_cp_refs_in_methods_annotations(scratch_class)) { 1958 // propagate failure back to caller 1959 return false; 1960 } 1961 1962 // rewrite constant pool references in the methods_parameter_annotations: 1963 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class)) { 1964 // propagate failure back to caller 1965 return false; 1966 } 1967 1968 // rewrite constant pool references in the methods_default_annotations: 1969 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class)) { 1970 // propagate failure back to caller 1971 return false; 1972 } 1973 1974 // rewrite constant pool references in the class_type_annotations: 1975 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class)) { 1976 // propagate failure back to caller 1977 return false; 1978 } 1979 1980 // rewrite constant pool references in the fields_type_annotations: 1981 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class)) { 1982 // propagate failure back to caller 1983 return false; 1984 } 1985 1986 // rewrite constant pool references in the methods_type_annotations: 1987 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class)) { 1988 // propagate failure back to caller 1989 return false; 1990 } 1991 1992 // There can be type annotations in the Code part of a method_info attribute. 1993 // These annotations are not accessible, even by reflection. 1994 // Currently they are not even parsed by the ClassFileParser. 1995 // If runtime access is added they will also need to be rewritten. 1996 1997 // rewrite source file name index: 1998 u2 source_file_name_idx = scratch_class->source_file_name_index(); 1999 if (source_file_name_idx != 0) { 2000 u2 new_source_file_name_idx = find_new_index(source_file_name_idx); 2001 if (new_source_file_name_idx != 0) { 2002 scratch_class->set_source_file_name_index(new_source_file_name_idx); 2003 } 2004 } 2005 2006 // rewrite class generic signature index: 2007 u2 generic_signature_index = scratch_class->generic_signature_index(); 2008 if (generic_signature_index != 0) { 2009 u2 new_generic_signature_index = find_new_index(generic_signature_index); 2010 if (new_generic_signature_index != 0) { 2011 scratch_class->set_generic_signature_index(new_generic_signature_index); 2012 } 2013 } 2014 2015 return true; 2016 } // end rewrite_cp_refs() 2017 2018 // Rewrite constant pool references in the NestHost and NestMembers attributes. 2019 bool VM_RedefineClasses::rewrite_cp_refs_in_nest_attributes( 2020 InstanceKlass* scratch_class) { 2021 2022 u2 cp_index = scratch_class->nest_host_index(); 2023 if (cp_index != 0) { 2024 scratch_class->set_nest_host_index(find_new_index(cp_index)); 2025 } 2026 Array<u2>* nest_members = scratch_class->nest_members(); 2027 for (int i = 0; i < nest_members->length(); i++) { 2028 u2 cp_index = nest_members->at(i); 2029 nest_members->at_put(i, find_new_index(cp_index)); 2030 } 2031 return true; 2032 } 2033 2034 // Rewrite constant pool references in the Record attribute. 2035 bool VM_RedefineClasses::rewrite_cp_refs_in_record_attribute(InstanceKlass* scratch_class) { 2036 Array<RecordComponent*>* components = scratch_class->record_components(); 2037 if (components != nullptr) { 2038 for (int i = 0; i < components->length(); i++) { 2039 RecordComponent* component = components->at(i); 2040 u2 cp_index = component->name_index(); 2041 component->set_name_index(find_new_index(cp_index)); 2042 cp_index = component->descriptor_index(); 2043 component->set_descriptor_index(find_new_index(cp_index)); 2044 cp_index = component->generic_signature_index(); 2045 if (cp_index != 0) { 2046 component->set_generic_signature_index(find_new_index(cp_index)); 2047 } 2048 2049 AnnotationArray* annotations = component->annotations(); 2050 if (annotations != nullptr && annotations->length() != 0) { 2051 int byte_i = 0; // byte index into annotations 2052 if (!rewrite_cp_refs_in_annotations_typeArray(annotations, byte_i)) { 2053 log_debug(redefine, class, annotation)("bad record_component_annotations at %d", i); 2054 // propagate failure back to caller 2055 return false; 2056 } 2057 } 2058 2059 AnnotationArray* type_annotations = component->type_annotations(); 2060 if (type_annotations != nullptr && type_annotations->length() != 0) { 2061 int byte_i = 0; // byte index into annotations 2062 if (!rewrite_cp_refs_in_annotations_typeArray(type_annotations, byte_i)) { 2063 log_debug(redefine, class, annotation)("bad record_component_type_annotations at %d", i); 2064 // propagate failure back to caller 2065 return false; 2066 } 2067 } 2068 } 2069 } 2070 return true; 2071 } 2072 2073 // Rewrite constant pool references in the PermittedSubclasses attribute. 2074 bool VM_RedefineClasses::rewrite_cp_refs_in_permitted_subclasses_attribute( 2075 InstanceKlass* scratch_class) { 2076 2077 Array<u2>* permitted_subclasses = scratch_class->permitted_subclasses(); 2078 assert(permitted_subclasses != nullptr, "unexpected null permitted_subclasses"); 2079 for (int i = 0; i < permitted_subclasses->length(); i++) { 2080 u2 cp_index = permitted_subclasses->at(i); 2081 permitted_subclasses->at_put(i, find_new_index(cp_index)); 2082 } 2083 return true; 2084 } 2085 2086 // Rewrite constant pool references in the methods. 2087 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(InstanceKlass* scratch_class) { 2088 2089 Array<Method*>* methods = scratch_class->methods(); 2090 2091 if (methods == nullptr || methods->length() == 0) { 2092 // no methods so nothing to do 2093 return true; 2094 } 2095 2096 JavaThread* THREAD = JavaThread::current(); // For exception macros. 2097 ExceptionMark em(THREAD); 2098 2099 // rewrite constant pool references in the methods: 2100 for (int i = methods->length() - 1; i >= 0; i--) { 2101 methodHandle method(THREAD, methods->at(i)); 2102 methodHandle new_method; 2103 rewrite_cp_refs_in_method(method, &new_method, THREAD); 2104 if (!new_method.is_null()) { 2105 // the method has been replaced so save the new method version 2106 // even in the case of an exception. original method is on the 2107 // deallocation list. 2108 methods->at_put(i, new_method()); 2109 } 2110 if (HAS_PENDING_EXCEPTION) { 2111 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 2112 log_info(redefine, class, load, exceptions)("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string()); 2113 // Need to clear pending exception here as the super caller sets 2114 // the JVMTI_ERROR_INTERNAL if the returned value is false. 2115 CLEAR_PENDING_EXCEPTION; 2116 return false; 2117 } 2118 } 2119 2120 return true; 2121 } 2122 2123 2124 // Rewrite constant pool references in the specific method. This code 2125 // was adapted from Rewriter::rewrite_method(). 2126 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method, 2127 methodHandle *new_method_p, TRAPS) { 2128 2129 *new_method_p = methodHandle(); // default is no new method 2130 2131 // We cache a pointer to the bytecodes here in code_base. If GC 2132 // moves the Method*, then the bytecodes will also move which 2133 // will likely cause a crash. We create a NoSafepointVerifier 2134 // object to detect whether we pass a possible safepoint in this 2135 // code block. 2136 NoSafepointVerifier nsv; 2137 2138 // Bytecodes and their length 2139 address code_base = method->code_base(); 2140 int code_length = method->code_size(); 2141 2142 int bc_length; 2143 for (int bci = 0; bci < code_length; bci += bc_length) { 2144 address bcp = code_base + bci; 2145 Bytecodes::Code c = (Bytecodes::Code)(*bcp); 2146 2147 bc_length = Bytecodes::length_for(c); 2148 if (bc_length == 0) { 2149 // More complicated bytecodes report a length of zero so 2150 // we have to try again a slightly different way. 2151 bc_length = Bytecodes::length_at(method(), bcp); 2152 } 2153 2154 assert(bc_length != 0, "impossible bytecode length"); 2155 2156 switch (c) { 2157 case Bytecodes::_ldc: 2158 { 2159 u1 cp_index = *(bcp + 1); 2160 u2 new_index = find_new_index(cp_index); 2161 2162 if (StressLdcRewrite && new_index == 0) { 2163 // If we are stressing ldc -> ldc_w rewriting, then we 2164 // always need a new_index value. 2165 new_index = cp_index; 2166 } 2167 if (new_index != 0) { 2168 // the original index is mapped so we have more work to do 2169 if (!StressLdcRewrite && new_index <= max_jubyte) { 2170 // The new value can still use ldc instead of ldc_w 2171 // unless we are trying to stress ldc -> ldc_w rewriting 2172 log_trace(redefine, class, constantpool) 2173 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index); 2174 // We checked that new_index fits in a u1 so this cast is safe 2175 *(bcp + 1) = (u1)new_index; 2176 } else { 2177 log_trace(redefine, class, constantpool) 2178 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index); 2179 // the new value needs ldc_w instead of ldc 2180 u_char inst_buffer[4]; // max instruction size is 4 bytes 2181 bcp = (address)inst_buffer; 2182 // construct new instruction sequence 2183 *bcp = Bytecodes::_ldc_w; 2184 bcp++; 2185 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w. 2186 // See comment below for difference between put_Java_u2() 2187 // and put_native_u2(). 2188 Bytes::put_Java_u2(bcp, new_index); 2189 2190 Relocator rc(method, nullptr /* no RelocatorListener needed */); 2191 methodHandle m; 2192 { 2193 PauseNoSafepointVerifier pnsv(&nsv); 2194 2195 // ldc is 2 bytes and ldc_w is 3 bytes 2196 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK); 2197 } 2198 2199 // return the new method so that the caller can update 2200 // the containing class 2201 *new_method_p = method = m; 2202 // switch our bytecode processing loop from the old method 2203 // to the new method 2204 code_base = method->code_base(); 2205 code_length = method->code_size(); 2206 bcp = code_base + bci; 2207 c = (Bytecodes::Code)(*bcp); 2208 bc_length = Bytecodes::length_for(c); 2209 assert(bc_length != 0, "sanity check"); 2210 } // end we need ldc_w instead of ldc 2211 } // end if there is a mapped index 2212 } break; 2213 2214 // these bytecodes have a two-byte constant pool index 2215 case Bytecodes::_anewarray : // fall through 2216 case Bytecodes::_checkcast : // fall through 2217 case Bytecodes::_getfield : // fall through 2218 case Bytecodes::_getstatic : // fall through 2219 case Bytecodes::_instanceof : // fall through 2220 case Bytecodes::_invokedynamic : // fall through 2221 case Bytecodes::_invokeinterface: // fall through 2222 case Bytecodes::_invokespecial : // fall through 2223 case Bytecodes::_invokestatic : // fall through 2224 case Bytecodes::_invokevirtual : // fall through 2225 case Bytecodes::_ldc_w : // fall through 2226 case Bytecodes::_ldc2_w : // fall through 2227 case Bytecodes::_multianewarray : // fall through 2228 case Bytecodes::_new : // fall through 2229 case Bytecodes::_putfield : // fall through 2230 case Bytecodes::_putstatic : 2231 { 2232 address p = bcp + 1; 2233 int cp_index = Bytes::get_Java_u2(p); 2234 u2 new_index = find_new_index(cp_index); 2235 if (new_index != 0) { 2236 // the original index is mapped so update w/ new value 2237 log_trace(redefine, class, constantpool) 2238 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),p2i(bcp), cp_index, new_index); 2239 // Rewriter::rewrite_method() uses put_native_u2() in this 2240 // situation because it is reusing the constant pool index 2241 // location for a native index into the ConstantPoolCache. 2242 // Since we are updating the constant pool index prior to 2243 // verification and ConstantPoolCache initialization, we 2244 // need to keep the new index in Java byte order. 2245 Bytes::put_Java_u2(p, new_index); 2246 } 2247 } break; 2248 default: 2249 break; 2250 } 2251 } // end for each bytecode 2252 } // end rewrite_cp_refs_in_method() 2253 2254 2255 // Rewrite constant pool references in the class_annotations field. 2256 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(InstanceKlass* scratch_class) { 2257 2258 AnnotationArray* class_annotations = scratch_class->class_annotations(); 2259 if (class_annotations == nullptr || class_annotations->length() == 0) { 2260 // no class_annotations so nothing to do 2261 return true; 2262 } 2263 2264 log_debug(redefine, class, annotation)("class_annotations length=%d", class_annotations->length()); 2265 2266 int byte_i = 0; // byte index into class_annotations 2267 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i); 2268 } 2269 2270 2271 // Rewrite constant pool references in an annotations typeArray. This 2272 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute 2273 // that is described in section 4.8.15 of the 2nd-edition of the VM spec: 2274 // 2275 // annotations_typeArray { 2276 // u2 num_annotations; 2277 // annotation annotations[num_annotations]; 2278 // } 2279 // 2280 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray( 2281 AnnotationArray* annotations_typeArray, int &byte_i_ref) { 2282 2283 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2284 // not enough room for num_annotations field 2285 log_debug(redefine, class, annotation)("length() is too small for num_annotations field"); 2286 return false; 2287 } 2288 2289 u2 num_annotations = Bytes::get_Java_u2((address) 2290 annotations_typeArray->adr_at(byte_i_ref)); 2291 byte_i_ref += 2; 2292 2293 log_debug(redefine, class, annotation)("num_annotations=%d", num_annotations); 2294 2295 int calc_num_annotations = 0; 2296 for (; calc_num_annotations < num_annotations; calc_num_annotations++) { 2297 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, byte_i_ref)) { 2298 log_debug(redefine, class, annotation)("bad annotation_struct at %d", calc_num_annotations); 2299 // propagate failure back to caller 2300 return false; 2301 } 2302 } 2303 assert(num_annotations == calc_num_annotations, "sanity check"); 2304 2305 return true; 2306 } // end rewrite_cp_refs_in_annotations_typeArray() 2307 2308 2309 // Rewrite constant pool references in the annotation struct portion of 2310 // an annotations_typeArray. This "structure" is from section 4.8.15 of 2311 // the 2nd-edition of the VM spec: 2312 // 2313 // struct annotation { 2314 // u2 type_index; 2315 // u2 num_element_value_pairs; 2316 // { 2317 // u2 element_name_index; 2318 // element_value value; 2319 // } element_value_pairs[num_element_value_pairs]; 2320 // } 2321 // 2322 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct( 2323 AnnotationArray* annotations_typeArray, int &byte_i_ref) { 2324 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) { 2325 // not enough room for smallest annotation_struct 2326 log_debug(redefine, class, annotation)("length() is too small for annotation_struct"); 2327 return false; 2328 } 2329 2330 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray, 2331 byte_i_ref, "type_index"); 2332 2333 u2 num_element_value_pairs = Bytes::get_Java_u2((address) 2334 annotations_typeArray->adr_at(byte_i_ref)); 2335 byte_i_ref += 2; 2336 2337 log_debug(redefine, class, annotation) 2338 ("type_index=%d num_element_value_pairs=%d", type_index, num_element_value_pairs); 2339 2340 int calc_num_element_value_pairs = 0; 2341 for (; calc_num_element_value_pairs < num_element_value_pairs; 2342 calc_num_element_value_pairs++) { 2343 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2344 // not enough room for another element_name_index, let alone 2345 // the rest of another component 2346 log_debug(redefine, class, annotation)("length() is too small for element_name_index"); 2347 return false; 2348 } 2349 2350 u2 element_name_index = rewrite_cp_ref_in_annotation_data( 2351 annotations_typeArray, byte_i_ref, 2352 "element_name_index"); 2353 2354 log_debug(redefine, class, annotation)("element_name_index=%d", element_name_index); 2355 2356 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, byte_i_ref)) { 2357 log_debug(redefine, class, annotation)("bad element_value at %d", calc_num_element_value_pairs); 2358 // propagate failure back to caller 2359 return false; 2360 } 2361 } // end for each component 2362 assert(num_element_value_pairs == calc_num_element_value_pairs, 2363 "sanity check"); 2364 2365 return true; 2366 } // end rewrite_cp_refs_in_annotation_struct() 2367 2368 2369 // Rewrite a constant pool reference at the current position in 2370 // annotations_typeArray if needed. Returns the original constant 2371 // pool reference if a rewrite was not needed or the new constant 2372 // pool reference if a rewrite was needed. 2373 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data( 2374 AnnotationArray* annotations_typeArray, int &byte_i_ref, 2375 const char * trace_mesg) { 2376 2377 address cp_index_addr = (address) 2378 annotations_typeArray->adr_at(byte_i_ref); 2379 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr); 2380 u2 new_cp_index = find_new_index(old_cp_index); 2381 if (new_cp_index != 0) { 2382 log_debug(redefine, class, annotation)("mapped old %s=%d", trace_mesg, old_cp_index); 2383 Bytes::put_Java_u2(cp_index_addr, new_cp_index); 2384 old_cp_index = new_cp_index; 2385 } 2386 byte_i_ref += 2; 2387 return old_cp_index; 2388 } 2389 2390 2391 // Rewrite constant pool references in the element_value portion of an 2392 // annotations_typeArray. This "structure" is from section 4.8.15.1 of 2393 // the 2nd-edition of the VM spec: 2394 // 2395 // struct element_value { 2396 // u1 tag; 2397 // union { 2398 // u2 const_value_index; 2399 // { 2400 // u2 type_name_index; 2401 // u2 const_name_index; 2402 // } enum_const_value; 2403 // u2 class_info_index; 2404 // annotation annotation_value; 2405 // struct { 2406 // u2 num_values; 2407 // element_value values[num_values]; 2408 // } array_value; 2409 // } value; 2410 // } 2411 // 2412 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value( 2413 AnnotationArray* annotations_typeArray, int &byte_i_ref) { 2414 2415 if ((byte_i_ref + 1) > annotations_typeArray->length()) { 2416 // not enough room for a tag let alone the rest of an element_value 2417 log_debug(redefine, class, annotation)("length() is too small for a tag"); 2418 return false; 2419 } 2420 2421 u1 tag = annotations_typeArray->at(byte_i_ref); 2422 byte_i_ref++; 2423 log_debug(redefine, class, annotation)("tag='%c'", tag); 2424 2425 switch (tag) { 2426 // These BaseType tag values are from Table 4.2 in VM spec: 2427 case JVM_SIGNATURE_BYTE: 2428 case JVM_SIGNATURE_CHAR: 2429 case JVM_SIGNATURE_DOUBLE: 2430 case JVM_SIGNATURE_FLOAT: 2431 case JVM_SIGNATURE_INT: 2432 case JVM_SIGNATURE_LONG: 2433 case JVM_SIGNATURE_SHORT: 2434 case JVM_SIGNATURE_BOOLEAN: 2435 2436 // The remaining tag values are from Table 4.8 in the 2nd-edition of 2437 // the VM spec: 2438 case 's': 2439 { 2440 // For the above tag values (including the BaseType values), 2441 // value.const_value_index is right union field. 2442 2443 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2444 // not enough room for a const_value_index 2445 log_debug(redefine, class, annotation)("length() is too small for a const_value_index"); 2446 return false; 2447 } 2448 2449 u2 const_value_index = rewrite_cp_ref_in_annotation_data( 2450 annotations_typeArray, byte_i_ref, 2451 "const_value_index"); 2452 2453 log_debug(redefine, class, annotation)("const_value_index=%d", const_value_index); 2454 } break; 2455 2456 case 'e': 2457 { 2458 // for the above tag value, value.enum_const_value is right union field 2459 2460 if ((byte_i_ref + 4) > annotations_typeArray->length()) { 2461 // not enough room for a enum_const_value 2462 log_debug(redefine, class, annotation)("length() is too small for a enum_const_value"); 2463 return false; 2464 } 2465 2466 u2 type_name_index = rewrite_cp_ref_in_annotation_data( 2467 annotations_typeArray, byte_i_ref, 2468 "type_name_index"); 2469 2470 u2 const_name_index = rewrite_cp_ref_in_annotation_data( 2471 annotations_typeArray, byte_i_ref, 2472 "const_name_index"); 2473 2474 log_debug(redefine, class, annotation) 2475 ("type_name_index=%d const_name_index=%d", type_name_index, const_name_index); 2476 } break; 2477 2478 case 'c': 2479 { 2480 // for the above tag value, value.class_info_index is right union field 2481 2482 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2483 // not enough room for a class_info_index 2484 log_debug(redefine, class, annotation)("length() is too small for a class_info_index"); 2485 return false; 2486 } 2487 2488 u2 class_info_index = rewrite_cp_ref_in_annotation_data( 2489 annotations_typeArray, byte_i_ref, 2490 "class_info_index"); 2491 2492 log_debug(redefine, class, annotation)("class_info_index=%d", class_info_index); 2493 } break; 2494 2495 case '@': 2496 // For the above tag value, value.attr_value is the right union 2497 // field. This is a nested annotation. 2498 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, byte_i_ref)) { 2499 // propagate failure back to caller 2500 return false; 2501 } 2502 break; 2503 2504 case JVM_SIGNATURE_ARRAY: 2505 { 2506 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2507 // not enough room for a num_values field 2508 log_debug(redefine, class, annotation)("length() is too small for a num_values field"); 2509 return false; 2510 } 2511 2512 // For the above tag value, value.array_value is the right union 2513 // field. This is an array of nested element_value. 2514 u2 num_values = Bytes::get_Java_u2((address) 2515 annotations_typeArray->adr_at(byte_i_ref)); 2516 byte_i_ref += 2; 2517 log_debug(redefine, class, annotation)("num_values=%d", num_values); 2518 2519 int calc_num_values = 0; 2520 for (; calc_num_values < num_values; calc_num_values++) { 2521 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, byte_i_ref)) { 2522 log_debug(redefine, class, annotation)("bad nested element_value at %d", calc_num_values); 2523 // propagate failure back to caller 2524 return false; 2525 } 2526 } 2527 assert(num_values == calc_num_values, "sanity check"); 2528 } break; 2529 2530 default: 2531 log_debug(redefine, class, annotation)("bad tag=0x%x", tag); 2532 return false; 2533 } // end decode tag field 2534 2535 return true; 2536 } // end rewrite_cp_refs_in_element_value() 2537 2538 2539 // Rewrite constant pool references in a fields_annotations field. 2540 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations( 2541 InstanceKlass* scratch_class) { 2542 2543 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations(); 2544 2545 if (fields_annotations == nullptr || fields_annotations->length() == 0) { 2546 // no fields_annotations so nothing to do 2547 return true; 2548 } 2549 2550 log_debug(redefine, class, annotation)("fields_annotations length=%d", fields_annotations->length()); 2551 2552 for (int i = 0; i < fields_annotations->length(); i++) { 2553 AnnotationArray* field_annotations = fields_annotations->at(i); 2554 if (field_annotations == nullptr || field_annotations->length() == 0) { 2555 // this field does not have any annotations so skip it 2556 continue; 2557 } 2558 2559 int byte_i = 0; // byte index into field_annotations 2560 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i)) { 2561 log_debug(redefine, class, annotation)("bad field_annotations at %d", i); 2562 // propagate failure back to caller 2563 return false; 2564 } 2565 } 2566 2567 return true; 2568 } // end rewrite_cp_refs_in_fields_annotations() 2569 2570 2571 // Rewrite constant pool references in a methods_annotations field. 2572 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations( 2573 InstanceKlass* scratch_class) { 2574 2575 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2576 Method* m = scratch_class->methods()->at(i); 2577 AnnotationArray* method_annotations = m->constMethod()->method_annotations(); 2578 2579 if (method_annotations == nullptr || method_annotations->length() == 0) { 2580 // this method does not have any annotations so skip it 2581 continue; 2582 } 2583 2584 int byte_i = 0; // byte index into method_annotations 2585 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i)) { 2586 log_debug(redefine, class, annotation)("bad method_annotations at %d", i); 2587 // propagate failure back to caller 2588 return false; 2589 } 2590 } 2591 2592 return true; 2593 } // end rewrite_cp_refs_in_methods_annotations() 2594 2595 2596 // Rewrite constant pool references in a methods_parameter_annotations 2597 // field. This "structure" is adapted from the 2598 // RuntimeVisibleParameterAnnotations_attribute described in section 2599 // 4.8.17 of the 2nd-edition of the VM spec: 2600 // 2601 // methods_parameter_annotations_typeArray { 2602 // u1 num_parameters; 2603 // { 2604 // u2 num_annotations; 2605 // annotation annotations[num_annotations]; 2606 // } parameter_annotations[num_parameters]; 2607 // } 2608 // 2609 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations( 2610 InstanceKlass* scratch_class) { 2611 2612 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2613 Method* m = scratch_class->methods()->at(i); 2614 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations(); 2615 if (method_parameter_annotations == nullptr 2616 || method_parameter_annotations->length() == 0) { 2617 // this method does not have any parameter annotations so skip it 2618 continue; 2619 } 2620 2621 if (method_parameter_annotations->length() < 1) { 2622 // not enough room for a num_parameters field 2623 log_debug(redefine, class, annotation)("length() is too small for a num_parameters field at %d", i); 2624 return false; 2625 } 2626 2627 int byte_i = 0; // byte index into method_parameter_annotations 2628 2629 u1 num_parameters = method_parameter_annotations->at(byte_i); 2630 byte_i++; 2631 2632 log_debug(redefine, class, annotation)("num_parameters=%d", num_parameters); 2633 2634 int calc_num_parameters = 0; 2635 for (; calc_num_parameters < num_parameters; calc_num_parameters++) { 2636 if (!rewrite_cp_refs_in_annotations_typeArray(method_parameter_annotations, byte_i)) { 2637 log_debug(redefine, class, annotation)("bad method_parameter_annotations at %d", calc_num_parameters); 2638 // propagate failure back to caller 2639 return false; 2640 } 2641 } 2642 assert(num_parameters == calc_num_parameters, "sanity check"); 2643 } 2644 2645 return true; 2646 } // end rewrite_cp_refs_in_methods_parameter_annotations() 2647 2648 2649 // Rewrite constant pool references in a methods_default_annotations 2650 // field. This "structure" is adapted from the AnnotationDefault_attribute 2651 // that is described in section 4.8.19 of the 2nd-edition of the VM spec: 2652 // 2653 // methods_default_annotations_typeArray { 2654 // element_value default_value; 2655 // } 2656 // 2657 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations( 2658 InstanceKlass* scratch_class) { 2659 2660 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2661 Method* m = scratch_class->methods()->at(i); 2662 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations(); 2663 if (method_default_annotations == nullptr 2664 || method_default_annotations->length() == 0) { 2665 // this method does not have any default annotations so skip it 2666 continue; 2667 } 2668 2669 int byte_i = 0; // byte index into method_default_annotations 2670 2671 if (!rewrite_cp_refs_in_element_value( 2672 method_default_annotations, byte_i)) { 2673 log_debug(redefine, class, annotation)("bad default element_value at %d", i); 2674 // propagate failure back to caller 2675 return false; 2676 } 2677 } 2678 2679 return true; 2680 } // end rewrite_cp_refs_in_methods_default_annotations() 2681 2682 2683 // Rewrite constant pool references in a class_type_annotations field. 2684 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations( 2685 InstanceKlass* scratch_class) { 2686 2687 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations(); 2688 if (class_type_annotations == nullptr || class_type_annotations->length() == 0) { 2689 // no class_type_annotations so nothing to do 2690 return true; 2691 } 2692 2693 log_debug(redefine, class, annotation)("class_type_annotations length=%d", class_type_annotations->length()); 2694 2695 int byte_i = 0; // byte index into class_type_annotations 2696 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations, 2697 byte_i, "ClassFile"); 2698 } // end rewrite_cp_refs_in_class_type_annotations() 2699 2700 2701 // Rewrite constant pool references in a fields_type_annotations field. 2702 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations(InstanceKlass* scratch_class) { 2703 2704 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations(); 2705 if (fields_type_annotations == nullptr || fields_type_annotations->length() == 0) { 2706 // no fields_type_annotations so nothing to do 2707 return true; 2708 } 2709 2710 log_debug(redefine, class, annotation)("fields_type_annotations length=%d", fields_type_annotations->length()); 2711 2712 for (int i = 0; i < fields_type_annotations->length(); i++) { 2713 AnnotationArray* field_type_annotations = fields_type_annotations->at(i); 2714 if (field_type_annotations == nullptr || field_type_annotations->length() == 0) { 2715 // this field does not have any annotations so skip it 2716 continue; 2717 } 2718 2719 int byte_i = 0; // byte index into field_type_annotations 2720 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations, 2721 byte_i, "field_info")) { 2722 log_debug(redefine, class, annotation)("bad field_type_annotations at %d", i); 2723 // propagate failure back to caller 2724 return false; 2725 } 2726 } 2727 2728 return true; 2729 } // end rewrite_cp_refs_in_fields_type_annotations() 2730 2731 2732 // Rewrite constant pool references in a methods_type_annotations field. 2733 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations( 2734 InstanceKlass* scratch_class) { 2735 2736 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2737 Method* m = scratch_class->methods()->at(i); 2738 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations(); 2739 2740 if (method_type_annotations == nullptr || method_type_annotations->length() == 0) { 2741 // this method does not have any annotations so skip it 2742 continue; 2743 } 2744 2745 log_debug(redefine, class, annotation)("methods type_annotations length=%d", method_type_annotations->length()); 2746 2747 int byte_i = 0; // byte index into method_type_annotations 2748 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations, 2749 byte_i, "method_info")) { 2750 log_debug(redefine, class, annotation)("bad method_type_annotations at %d", i); 2751 // propagate failure back to caller 2752 return false; 2753 } 2754 } 2755 2756 return true; 2757 } // end rewrite_cp_refs_in_methods_type_annotations() 2758 2759 2760 // Rewrite constant pool references in a type_annotations 2761 // field. This "structure" is adapted from the 2762 // RuntimeVisibleTypeAnnotations_attribute described in 2763 // section 4.7.20 of the Java SE 8 Edition of the VM spec: 2764 // 2765 // type_annotations_typeArray { 2766 // u2 num_annotations; 2767 // type_annotation annotations[num_annotations]; 2768 // } 2769 // 2770 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray( 2771 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2772 const char * location_mesg) { 2773 2774 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2775 // not enough room for num_annotations field 2776 log_debug(redefine, class, annotation)("length() is too small for num_annotations field"); 2777 return false; 2778 } 2779 2780 u2 num_annotations = Bytes::get_Java_u2((address) 2781 type_annotations_typeArray->adr_at(byte_i_ref)); 2782 byte_i_ref += 2; 2783 2784 log_debug(redefine, class, annotation)("num_type_annotations=%d", num_annotations); 2785 2786 int calc_num_annotations = 0; 2787 for (; calc_num_annotations < num_annotations; calc_num_annotations++) { 2788 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray, 2789 byte_i_ref, location_mesg)) { 2790 log_debug(redefine, class, annotation)("bad type_annotation_struct at %d", calc_num_annotations); 2791 // propagate failure back to caller 2792 return false; 2793 } 2794 } 2795 assert(num_annotations == calc_num_annotations, "sanity check"); 2796 2797 if (byte_i_ref != type_annotations_typeArray->length()) { 2798 log_debug(redefine, class, annotation) 2799 ("read wrong amount of bytes at end of processing type_annotations_typeArray (%d of %d bytes were read)", 2800 byte_i_ref, type_annotations_typeArray->length()); 2801 return false; 2802 } 2803 2804 return true; 2805 } // end rewrite_cp_refs_in_type_annotations_typeArray() 2806 2807 2808 // Rewrite constant pool references in a type_annotation 2809 // field. This "structure" is adapted from the 2810 // RuntimeVisibleTypeAnnotations_attribute described in 2811 // section 4.7.20 of the Java SE 8 Edition of the VM spec: 2812 // 2813 // type_annotation { 2814 // u1 target_type; 2815 // union { 2816 // type_parameter_target; 2817 // supertype_target; 2818 // type_parameter_bound_target; 2819 // empty_target; 2820 // method_formal_parameter_target; 2821 // throws_target; 2822 // localvar_target; 2823 // catch_target; 2824 // offset_target; 2825 // type_argument_target; 2826 // } target_info; 2827 // type_path target_path; 2828 // annotation anno; 2829 // } 2830 // 2831 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct( 2832 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2833 const char * location_mesg) { 2834 2835 if (!skip_type_annotation_target(type_annotations_typeArray, 2836 byte_i_ref, location_mesg)) { 2837 return false; 2838 } 2839 2840 if (!skip_type_annotation_type_path(type_annotations_typeArray, byte_i_ref)) { 2841 return false; 2842 } 2843 2844 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray, byte_i_ref)) { 2845 return false; 2846 } 2847 2848 return true; 2849 } // end rewrite_cp_refs_in_type_annotation_struct() 2850 2851 2852 // Read, verify and skip over the target_type and target_info part 2853 // so that rewriting can continue in the later parts of the struct. 2854 // 2855 // u1 target_type; 2856 // union { 2857 // type_parameter_target; 2858 // supertype_target; 2859 // type_parameter_bound_target; 2860 // empty_target; 2861 // method_formal_parameter_target; 2862 // throws_target; 2863 // localvar_target; 2864 // catch_target; 2865 // offset_target; 2866 // type_argument_target; 2867 // } target_info; 2868 // 2869 bool VM_RedefineClasses::skip_type_annotation_target( 2870 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2871 const char * location_mesg) { 2872 2873 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2874 // not enough room for a target_type let alone the rest of a type_annotation 2875 log_debug(redefine, class, annotation)("length() is too small for a target_type"); 2876 return false; 2877 } 2878 2879 u1 target_type = type_annotations_typeArray->at(byte_i_ref); 2880 byte_i_ref += 1; 2881 log_debug(redefine, class, annotation)("target_type=0x%.2x", target_type); 2882 log_debug(redefine, class, annotation)("location=%s", location_mesg); 2883 2884 // Skip over target_info 2885 switch (target_type) { 2886 case 0x00: 2887 // kind: type parameter declaration of generic class or interface 2888 // location: ClassFile 2889 case 0x01: 2890 // kind: type parameter declaration of generic method or constructor 2891 // location: method_info 2892 2893 { 2894 // struct: 2895 // type_parameter_target { 2896 // u1 type_parameter_index; 2897 // } 2898 // 2899 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2900 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_target"); 2901 return false; 2902 } 2903 2904 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2905 byte_i_ref += 1; 2906 2907 log_debug(redefine, class, annotation)("type_parameter_target: type_parameter_index=%d", type_parameter_index); 2908 } break; 2909 2910 case 0x10: 2911 // kind: type in extends clause of class or interface declaration 2912 // or in implements clause of interface declaration 2913 // location: ClassFile 2914 2915 { 2916 // struct: 2917 // supertype_target { 2918 // u2 supertype_index; 2919 // } 2920 // 2921 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2922 log_debug(redefine, class, annotation)("length() is too small for a supertype_target"); 2923 return false; 2924 } 2925 2926 u2 supertype_index = Bytes::get_Java_u2((address) 2927 type_annotations_typeArray->adr_at(byte_i_ref)); 2928 byte_i_ref += 2; 2929 2930 log_debug(redefine, class, annotation)("supertype_target: supertype_index=%d", supertype_index); 2931 } break; 2932 2933 case 0x11: 2934 // kind: type in bound of type parameter declaration of generic class or interface 2935 // location: ClassFile 2936 case 0x12: 2937 // kind: type in bound of type parameter declaration of generic method or constructor 2938 // location: method_info 2939 2940 { 2941 // struct: 2942 // type_parameter_bound_target { 2943 // u1 type_parameter_index; 2944 // u1 bound_index; 2945 // } 2946 // 2947 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2948 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_bound_target"); 2949 return false; 2950 } 2951 2952 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2953 byte_i_ref += 1; 2954 u1 bound_index = type_annotations_typeArray->at(byte_i_ref); 2955 byte_i_ref += 1; 2956 2957 log_debug(redefine, class, annotation) 2958 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d", type_parameter_index, bound_index); 2959 } break; 2960 2961 case 0x13: 2962 // kind: type in field declaration 2963 // location: field_info 2964 case 0x14: 2965 // kind: return type of method, or type of newly constructed object 2966 // location: method_info 2967 case 0x15: 2968 // kind: receiver type of method or constructor 2969 // location: method_info 2970 2971 { 2972 // struct: 2973 // empty_target { 2974 // } 2975 // 2976 log_debug(redefine, class, annotation)("empty_target"); 2977 } break; 2978 2979 case 0x16: 2980 // kind: type in formal parameter declaration of method, constructor, or lambda expression 2981 // location: method_info 2982 2983 { 2984 // struct: 2985 // formal_parameter_target { 2986 // u1 formal_parameter_index; 2987 // } 2988 // 2989 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2990 log_debug(redefine, class, annotation)("length() is too small for a formal_parameter_target"); 2991 return false; 2992 } 2993 2994 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2995 byte_i_ref += 1; 2996 2997 log_debug(redefine, class, annotation) 2998 ("formal_parameter_target: formal_parameter_index=%d", formal_parameter_index); 2999 } break; 3000 3001 case 0x17: 3002 // kind: type in throws clause of method or constructor 3003 // location: method_info 3004 3005 { 3006 // struct: 3007 // throws_target { 3008 // u2 throws_type_index 3009 // } 3010 // 3011 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 3012 log_debug(redefine, class, annotation)("length() is too small for a throws_target"); 3013 return false; 3014 } 3015 3016 u2 throws_type_index = Bytes::get_Java_u2((address) 3017 type_annotations_typeArray->adr_at(byte_i_ref)); 3018 byte_i_ref += 2; 3019 3020 log_debug(redefine, class, annotation)("throws_target: throws_type_index=%d", throws_type_index); 3021 } break; 3022 3023 case 0x40: 3024 // kind: type in local variable declaration 3025 // location: Code 3026 case 0x41: 3027 // kind: type in resource variable declaration 3028 // location: Code 3029 3030 { 3031 // struct: 3032 // localvar_target { 3033 // u2 table_length; 3034 // struct { 3035 // u2 start_pc; 3036 // u2 length; 3037 // u2 index; 3038 // } table[table_length]; 3039 // } 3040 // 3041 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 3042 // not enough room for a table_length let alone the rest of a localvar_target 3043 log_debug(redefine, class, annotation)("length() is too small for a localvar_target table_length"); 3044 return false; 3045 } 3046 3047 u2 table_length = Bytes::get_Java_u2((address) 3048 type_annotations_typeArray->adr_at(byte_i_ref)); 3049 byte_i_ref += 2; 3050 3051 log_debug(redefine, class, annotation)("localvar_target: table_length=%d", table_length); 3052 3053 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry 3054 int table_size = table_length * table_struct_size; 3055 3056 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) { 3057 // not enough room for a table 3058 log_debug(redefine, class, annotation)("length() is too small for a table array of length %d", table_length); 3059 return false; 3060 } 3061 3062 // Skip over table 3063 byte_i_ref += table_size; 3064 } break; 3065 3066 case 0x42: 3067 // kind: type in exception parameter declaration 3068 // location: Code 3069 3070 { 3071 // struct: 3072 // catch_target { 3073 // u2 exception_table_index; 3074 // } 3075 // 3076 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 3077 log_debug(redefine, class, annotation)("length() is too small for a catch_target"); 3078 return false; 3079 } 3080 3081 u2 exception_table_index = Bytes::get_Java_u2((address) 3082 type_annotations_typeArray->adr_at(byte_i_ref)); 3083 byte_i_ref += 2; 3084 3085 log_debug(redefine, class, annotation)("catch_target: exception_table_index=%d", exception_table_index); 3086 } break; 3087 3088 case 0x43: 3089 // kind: type in instanceof expression 3090 // location: Code 3091 case 0x44: 3092 // kind: type in new expression 3093 // location: Code 3094 case 0x45: 3095 // kind: type in method reference expression using ::new 3096 // location: Code 3097 case 0x46: 3098 // kind: type in method reference expression using ::Identifier 3099 // location: Code 3100 3101 { 3102 // struct: 3103 // offset_target { 3104 // u2 offset; 3105 // } 3106 // 3107 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 3108 log_debug(redefine, class, annotation)("length() is too small for a offset_target"); 3109 return false; 3110 } 3111 3112 u2 offset = Bytes::get_Java_u2((address) 3113 type_annotations_typeArray->adr_at(byte_i_ref)); 3114 byte_i_ref += 2; 3115 3116 log_debug(redefine, class, annotation)("offset_target: offset=%d", offset); 3117 } break; 3118 3119 case 0x47: 3120 // kind: type in cast expression 3121 // location: Code 3122 case 0x48: 3123 // kind: type argument for generic constructor in new expression or 3124 // explicit constructor invocation statement 3125 // location: Code 3126 case 0x49: 3127 // kind: type argument for generic method in method invocation expression 3128 // location: Code 3129 case 0x4A: 3130 // kind: type argument for generic constructor in method reference expression using ::new 3131 // location: Code 3132 case 0x4B: 3133 // kind: type argument for generic method in method reference expression using ::Identifier 3134 // location: Code 3135 3136 { 3137 // struct: 3138 // type_argument_target { 3139 // u2 offset; 3140 // u1 type_argument_index; 3141 // } 3142 // 3143 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) { 3144 log_debug(redefine, class, annotation)("length() is too small for a type_argument_target"); 3145 return false; 3146 } 3147 3148 u2 offset = Bytes::get_Java_u2((address) 3149 type_annotations_typeArray->adr_at(byte_i_ref)); 3150 byte_i_ref += 2; 3151 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref); 3152 byte_i_ref += 1; 3153 3154 log_debug(redefine, class, annotation) 3155 ("type_argument_target: offset=%d, type_argument_index=%d", offset, type_argument_index); 3156 } break; 3157 3158 default: 3159 log_debug(redefine, class, annotation)("unknown target_type"); 3160 #ifdef ASSERT 3161 ShouldNotReachHere(); 3162 #endif 3163 return false; 3164 } 3165 3166 return true; 3167 } // end skip_type_annotation_target() 3168 3169 3170 // Read, verify and skip over the type_path part so that rewriting 3171 // can continue in the later parts of the struct. 3172 // 3173 // type_path { 3174 // u1 path_length; 3175 // { 3176 // u1 type_path_kind; 3177 // u1 type_argument_index; 3178 // } path[path_length]; 3179 // } 3180 // 3181 bool VM_RedefineClasses::skip_type_annotation_type_path( 3182 AnnotationArray* type_annotations_typeArray, int &byte_i_ref) { 3183 3184 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 3185 // not enough room for a path_length let alone the rest of the type_path 3186 log_debug(redefine, class, annotation)("length() is too small for a type_path"); 3187 return false; 3188 } 3189 3190 u1 path_length = type_annotations_typeArray->at(byte_i_ref); 3191 byte_i_ref += 1; 3192 3193 log_debug(redefine, class, annotation)("type_path: path_length=%d", path_length); 3194 3195 int calc_path_length = 0; 3196 for (; calc_path_length < path_length; calc_path_length++) { 3197 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) { 3198 // not enough room for a path 3199 log_debug(redefine, class, annotation) 3200 ("length() is too small for path entry %d of %d", calc_path_length, path_length); 3201 return false; 3202 } 3203 3204 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref); 3205 byte_i_ref += 1; 3206 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref); 3207 byte_i_ref += 1; 3208 3209 log_debug(redefine, class, annotation) 3210 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d", 3211 calc_path_length, type_path_kind, type_argument_index); 3212 3213 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) { 3214 // not enough room for a path 3215 log_debug(redefine, class, annotation)("inconsistent type_path values"); 3216 return false; 3217 } 3218 } 3219 assert(path_length == calc_path_length, "sanity check"); 3220 3221 return true; 3222 } // end skip_type_annotation_type_path() 3223 3224 3225 // Rewrite constant pool references in the method's stackmap table. 3226 // These "structures" are adapted from the StackMapTable_attribute that 3227 // is described in section 4.8.4 of the 6.0 version of the VM spec 3228 // (dated 2005.10.26): 3229 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf 3230 // 3231 // stack_map { 3232 // u2 number_of_entries; 3233 // stack_map_frame entries[number_of_entries]; 3234 // } 3235 // 3236 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table( 3237 const methodHandle& method) { 3238 3239 if (!method->has_stackmap_table()) { 3240 return; 3241 } 3242 3243 AnnotationArray* stackmap_data = method->stackmap_data(); 3244 address stackmap_p = (address)stackmap_data->adr_at(0); 3245 address stackmap_end = stackmap_p + stackmap_data->length(); 3246 3247 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries"); 3248 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p); 3249 stackmap_p += 2; 3250 3251 log_debug(redefine, class, stackmap)("number_of_entries=%u", number_of_entries); 3252 3253 // walk through each stack_map_frame 3254 u2 calc_number_of_entries = 0; 3255 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) { 3256 // The stack_map_frame structure is a u1 frame_type followed by 3257 // 0 or more bytes of data: 3258 // 3259 // union stack_map_frame { 3260 // same_frame; 3261 // same_locals_1_stack_item_frame; 3262 // same_locals_1_stack_item_frame_extended; 3263 // chop_frame; 3264 // same_frame_extended; 3265 // append_frame; 3266 // full_frame; 3267 // } 3268 3269 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type"); 3270 u1 frame_type = *stackmap_p; 3271 stackmap_p++; 3272 3273 // same_frame { 3274 // u1 frame_type = SAME; /* 0-63 */ 3275 // } 3276 if (frame_type <= StackMapReader::SAME_FRAME_END) { 3277 // nothing more to do for same_frame 3278 } 3279 3280 // same_locals_1_stack_item_frame { 3281 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */ 3282 // verification_type_info stack[1]; 3283 // } 3284 else if (frame_type >= StackMapReader::SAME_LOCALS_1_STACK_ITEM_FRAME_START && 3285 frame_type <= StackMapReader::SAME_LOCALS_1_STACK_ITEM_FRAME_END) { 3286 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3287 calc_number_of_entries, frame_type); 3288 } 3289 3290 // reserved for future use 3291 else if (frame_type >= StackMapReader::RESERVED_START && 3292 frame_type <= StackMapReader::RESERVED_END) { 3293 // nothing more to do for reserved frame_types 3294 } 3295 3296 // same_locals_1_stack_item_frame_extended { 3297 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */ 3298 // u2 offset_delta; 3299 // verification_type_info stack[1]; 3300 // } 3301 else if (frame_type == StackMapReader::SAME_LOCALS_1_STACK_ITEM_EXTENDED) { 3302 stackmap_p += 2; 3303 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3304 calc_number_of_entries, frame_type); 3305 } 3306 3307 // chop_frame { 3308 // u1 frame_type = CHOP; /* 248-250 */ 3309 // u2 offset_delta; 3310 // } 3311 else if (frame_type >= StackMapReader::CHOP_FRAME_START && 3312 frame_type <= StackMapReader::CHOP_FRAME_END) { 3313 stackmap_p += 2; 3314 } 3315 3316 // same_frame_extended { 3317 // u1 frame_type = SAME_EXTENDED; /* 251 */ 3318 // u2 offset_delta; 3319 // } 3320 else if (frame_type == StackMapReader::SAME_FRAME_EXTENDED) { 3321 stackmap_p += 2; 3322 } 3323 3324 // append_frame { 3325 // u1 frame_type = APPEND; /* 252-254 */ 3326 // u2 offset_delta; 3327 // verification_type_info locals[frame_type - SAME_EXTENDED]; 3328 // } 3329 else if (frame_type >= StackMapReader::APPEND_FRAME_START && 3330 frame_type <= StackMapReader::APPEND_FRAME_END) { 3331 assert(stackmap_p + 2 <= stackmap_end, 3332 "no room for offset_delta"); 3333 stackmap_p += 2; 3334 u1 len = frame_type - StackMapReader::APPEND_FRAME_START + 1; 3335 for (u1 i = 0; i < len; i++) { 3336 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3337 calc_number_of_entries, frame_type); 3338 } 3339 } 3340 3341 // full_frame { 3342 // u1 frame_type = FULL_FRAME; /* 255 */ 3343 // u2 offset_delta; 3344 // u2 number_of_locals; 3345 // verification_type_info locals[number_of_locals]; 3346 // u2 number_of_stack_items; 3347 // verification_type_info stack[number_of_stack_items]; 3348 // } 3349 else if (frame_type == StackMapReader::FULL_FRAME) { 3350 assert(stackmap_p + 2 + 2 <= stackmap_end, 3351 "no room for smallest full_frame"); 3352 stackmap_p += 2; 3353 3354 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p); 3355 stackmap_p += 2; 3356 3357 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) { 3358 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3359 calc_number_of_entries, frame_type); 3360 } 3361 3362 // Use the largest size for the number_of_stack_items, but only get 3363 // the right number of bytes. 3364 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p); 3365 stackmap_p += 2; 3366 3367 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) { 3368 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3369 calc_number_of_entries, frame_type); 3370 } 3371 } 3372 } // end while there is a stack_map_frame 3373 assert(number_of_entries == calc_number_of_entries, "sanity check"); 3374 } // end rewrite_cp_refs_in_stack_map_table() 3375 3376 3377 // Rewrite constant pool references in the verification type info 3378 // portion of the method's stackmap table. These "structures" are 3379 // adapted from the StackMapTable_attribute that is described in 3380 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26): 3381 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf 3382 // 3383 // The verification_type_info structure is a u1 tag followed by 0 or 3384 // more bytes of data: 3385 // 3386 // union verification_type_info { 3387 // Top_variable_info; 3388 // Integer_variable_info; 3389 // Float_variable_info; 3390 // Long_variable_info; 3391 // Double_variable_info; 3392 // Null_variable_info; 3393 // UninitializedThis_variable_info; 3394 // Object_variable_info; 3395 // Uninitialized_variable_info; 3396 // } 3397 // 3398 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info( 3399 address& stackmap_p_ref, address stackmap_end, u2 frame_i, 3400 u1 frame_type) { 3401 3402 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag"); 3403 u1 tag = *stackmap_p_ref; 3404 stackmap_p_ref++; 3405 3406 switch (tag) { 3407 // Top_variable_info { 3408 // u1 tag = ITEM_Top; /* 0 */ 3409 // } 3410 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top 3411 case 0: // fall through 3412 3413 // Integer_variable_info { 3414 // u1 tag = ITEM_Integer; /* 1 */ 3415 // } 3416 case ITEM_Integer: // fall through 3417 3418 // Float_variable_info { 3419 // u1 tag = ITEM_Float; /* 2 */ 3420 // } 3421 case ITEM_Float: // fall through 3422 3423 // Double_variable_info { 3424 // u1 tag = ITEM_Double; /* 3 */ 3425 // } 3426 case ITEM_Double: // fall through 3427 3428 // Long_variable_info { 3429 // u1 tag = ITEM_Long; /* 4 */ 3430 // } 3431 case ITEM_Long: // fall through 3432 3433 // Null_variable_info { 3434 // u1 tag = ITEM_Null; /* 5 */ 3435 // } 3436 case ITEM_Null: // fall through 3437 3438 // UninitializedThis_variable_info { 3439 // u1 tag = ITEM_UninitializedThis; /* 6 */ 3440 // } 3441 case ITEM_UninitializedThis: 3442 // nothing more to do for the above tag types 3443 break; 3444 3445 // Object_variable_info { 3446 // u1 tag = ITEM_Object; /* 7 */ 3447 // u2 cpool_index; 3448 // } 3449 case ITEM_Object: 3450 { 3451 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index"); 3452 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref); 3453 u2 new_cp_index = find_new_index(cpool_index); 3454 if (new_cp_index != 0) { 3455 log_debug(redefine, class, stackmap)("mapped old cpool_index=%d", cpool_index); 3456 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index); 3457 cpool_index = new_cp_index; 3458 } 3459 stackmap_p_ref += 2; 3460 3461 log_debug(redefine, class, stackmap) 3462 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i, frame_type, cpool_index); 3463 } break; 3464 3465 // Uninitialized_variable_info { 3466 // u1 tag = ITEM_Uninitialized; /* 8 */ 3467 // u2 offset; 3468 // } 3469 case ITEM_Uninitialized: 3470 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset"); 3471 stackmap_p_ref += 2; 3472 break; 3473 3474 default: 3475 log_debug(redefine, class, stackmap)("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag); 3476 ShouldNotReachHere(); 3477 break; 3478 } // end switch (tag) 3479 } // end rewrite_cp_refs_in_verification_type_info() 3480 3481 3482 // Change the constant pool associated with klass scratch_class to scratch_cp. 3483 // scratch_cp_length elements are copied from scratch_cp to a smaller constant pool 3484 // and the smaller constant pool is associated with scratch_class. 3485 void VM_RedefineClasses::set_new_constant_pool( 3486 ClassLoaderData* loader_data, 3487 InstanceKlass* scratch_class, constantPoolHandle scratch_cp, 3488 int scratch_cp_length, TRAPS) { 3489 assert(scratch_cp->length() >= scratch_cp_length, "sanity check"); 3490 3491 // scratch_cp is a merged constant pool and has enough space for a 3492 // worst case merge situation. We want to associate the minimum 3493 // sized constant pool with the klass to save space. 3494 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK); 3495 constantPoolHandle smaller_cp(THREAD, cp); 3496 3497 // preserve version() value in the smaller copy 3498 int version = scratch_cp->version(); 3499 assert(version != 0, "sanity check"); 3500 smaller_cp->set_version(version); 3501 3502 // attach klass to new constant pool 3503 // reference to the cp holder is needed for copy_operands() 3504 smaller_cp->set_pool_holder(scratch_class); 3505 3506 smaller_cp->copy_fields(scratch_cp()); 3507 3508 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD); 3509 if (HAS_PENDING_EXCEPTION) { 3510 // Exception is handled in the caller 3511 loader_data->add_to_deallocate_list(smaller_cp()); 3512 return; 3513 } 3514 scratch_cp = smaller_cp; 3515 3516 // attach new constant pool to klass 3517 scratch_class->set_constants(scratch_cp()); 3518 scratch_cp->initialize_unresolved_klasses(loader_data, CHECK); 3519 3520 int i; // for portability 3521 3522 // update each field in klass to use new constant pool indices as needed 3523 int java_fields; 3524 int injected_fields; 3525 bool update_required = false; 3526 GrowableArray<FieldInfo>* fields = FieldInfoStream::create_FieldInfoArray(scratch_class->fieldinfo_stream(), &java_fields, &injected_fields); 3527 for (int i = 0; i < java_fields; i++) { 3528 FieldInfo* fi = fields->adr_at(i); 3529 jshort cur_index = fi->name_index(); 3530 jshort new_index = find_new_index(cur_index); 3531 if (new_index != 0) { 3532 log_trace(redefine, class, constantpool)("field-name_index change: %d to %d", cur_index, new_index); 3533 fi->set_name_index(new_index); 3534 update_required = true; 3535 } 3536 cur_index = fi->signature_index(); 3537 new_index = find_new_index(cur_index); 3538 if (new_index != 0) { 3539 log_trace(redefine, class, constantpool)("field-signature_index change: %d to %d", cur_index, new_index); 3540 fi->set_signature_index(new_index); 3541 update_required = true; 3542 } 3543 cur_index = fi->initializer_index(); 3544 new_index = find_new_index(cur_index); 3545 if (new_index != 0) { 3546 log_trace(redefine, class, constantpool)("field-initval_index change: %d to %d", cur_index, new_index); 3547 fi->set_initializer_index(new_index); 3548 update_required = true; 3549 } 3550 cur_index = fi->generic_signature_index(); 3551 new_index = find_new_index(cur_index); 3552 if (new_index != 0) { 3553 log_trace(redefine, class, constantpool)("field-generic_signature change: %d to %d", cur_index, new_index); 3554 fi->set_generic_signature_index(new_index); 3555 update_required = true; 3556 } 3557 } 3558 if (update_required) { 3559 Array<u1>* old_stream = scratch_class->fieldinfo_stream(); 3560 assert(fields->length() == (java_fields + injected_fields), "Must be"); 3561 Array<u1>* new_fis = FieldInfoStream::create_FieldInfoStream(fields, java_fields, injected_fields, scratch_class->class_loader_data(), CHECK); 3562 scratch_class->set_fieldinfo_stream(new_fis); 3563 MetadataFactory::free_array<u1>(scratch_class->class_loader_data(), old_stream); 3564 3565 Array<u1>* old_table = scratch_class->fieldinfo_search_table(); 3566 Array<u1>* search_table = FieldInfoStream::create_search_table(scratch_class->constants(), new_fis, scratch_class->class_loader_data(), CHECK); 3567 scratch_class->set_fieldinfo_search_table(search_table); 3568 MetadataFactory::free_array<u1>(scratch_class->class_loader_data(), old_table); 3569 3570 DEBUG_ONLY(FieldInfoStream::validate_search_table(scratch_class->constants(), new_fis, search_table)); 3571 } 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 u2 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 u2 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->constMethod()->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 u2 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() != nullptr) { 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 != nullptr) { 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 != nullptr; 3785 pv_node = pv_node->previous_versions()) { 3786 cp_cache = pv_node->constants()->cache(); 3787 if (cp_cache != nullptr) { 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 // The method_idnum should be within the range of 1..number-of-methods 3798 // until incremented later for obsolete methods. 3799 // The increment is so if a jmethodID is created for an old obsolete method 3800 // it gets a new jmethodID cache slot in the InstanceKlass. 3801 // They're cleaned out later when all methods of the previous version are purged. 3802 assert(old_method->method_idnum() <= _old_methods->length(), 3803 "shouldn't be incremented yet for obsolete methods"); 3804 jmethodID jmid = old_method->find_jmethod_id_or_null(); 3805 if (jmid != nullptr) { 3806 // There is a jmethodID, change it to point to the new method 3807 Method* new_method = _matching_new_methods[j]; 3808 Method::change_method_associated_with_jmethod_id(jmid, new_method); 3809 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j], 3810 "should be replaced"); 3811 } 3812 } 3813 } 3814 3815 int VM_RedefineClasses::check_methods_and_mark_as_obsolete() { 3816 int emcp_method_count = 0; 3817 int obsolete_count = 0; 3818 int old_index = 0; 3819 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) { 3820 Method* old_method = _matching_old_methods[j]; 3821 Method* new_method = _matching_new_methods[j]; 3822 Method* old_array_method; 3823 3824 // Maintain an old_index into the _old_methods array by skipping 3825 // deleted methods 3826 while ((old_array_method = _old_methods->at(old_index)) != old_method) { 3827 ++old_index; 3828 } 3829 3830 if (MethodComparator::methods_EMCP(old_method, new_method)) { 3831 // The EMCP definition from JSR-163 requires the bytecodes to be 3832 // the same with the exception of constant pool indices which may 3833 // differ. However, the constants referred to by those indices 3834 // must be the same. 3835 // 3836 // We use methods_EMCP() for comparison since constant pool 3837 // merging can remove duplicate constant pool entries that were 3838 // present in the old method and removed from the rewritten new 3839 // method. A faster binary comparison function would consider the 3840 // old and new methods to be different when they are actually 3841 // EMCP. 3842 // 3843 // The old and new methods are EMCP and you would think that we 3844 // could get rid of one of them here and now and save some space. 3845 // However, the concept of EMCP only considers the bytecodes and 3846 // the constant pool entries in the comparison. Other things, 3847 // e.g., the line number table (LNT) or the local variable table 3848 // (LVT) don't count in the comparison. So the new (and EMCP) 3849 // method can have a new LNT that we need so we can't just 3850 // overwrite the new method with the old method. 3851 // 3852 // When this routine is called, we have already attached the new 3853 // methods to the_class so the old methods are effectively 3854 // overwritten. However, if an old method is still executing, 3855 // then the old method cannot be collected until sometime after 3856 // the old method call has returned. So the overwriting of old 3857 // methods by new methods will save us space except for those 3858 // (hopefully few) old methods that are still executing. 3859 // 3860 // A method refers to a ConstMethod* and this presents another 3861 // possible avenue to space savings. The ConstMethod* in the 3862 // new method contains possibly new attributes (LNT, LVT, etc). 3863 // At first glance, it seems possible to save space by replacing 3864 // the ConstMethod* in the old method with the ConstMethod* 3865 // from the new method. The old and new methods would share the 3866 // same ConstMethod* and we would save the space occupied by 3867 // the old ConstMethod*. However, the ConstMethod* contains 3868 // a back reference to the containing method. Sharing the 3869 // ConstMethod* between two methods could lead to confusion in 3870 // the code that uses the back reference. This would lead to 3871 // brittle code that could be broken in non-obvious ways now or 3872 // in the future. 3873 // 3874 // Another possibility is to copy the ConstMethod* from the new 3875 // method to the old method and then overwrite the new method with 3876 // the old method. Since the ConstMethod* contains the bytecodes 3877 // for the method embedded in the oop, this option would change 3878 // the bytecodes out from under any threads executing the old 3879 // method and make the thread's bcp invalid. Since EMCP requires 3880 // that the bytecodes be the same modulo constant pool indices, it 3881 // is straight forward to compute the correct new bcp in the new 3882 // ConstMethod* from the old bcp in the old ConstMethod*. The 3883 // time consuming part would be searching all the frames in all 3884 // of the threads to find all of the calls to the old method. 3885 // 3886 // It looks like we will have to live with the limited savings 3887 // that we get from effectively overwriting the old methods 3888 // when the new methods are attached to the_class. 3889 3890 // Count number of methods that are EMCP. The method will be marked 3891 // old but not obsolete if it is EMCP. 3892 emcp_method_count++; 3893 3894 // An EMCP method is _not_ obsolete. An obsolete method has a 3895 // different jmethodID than the current method. An EMCP method 3896 // has the same jmethodID as the current method. Having the 3897 // same jmethodID for all EMCP versions of a method allows for 3898 // a consistent view of the EMCP methods regardless of which 3899 // EMCP method you happen to have in hand. For example, a 3900 // breakpoint set in one EMCP method will work for all EMCP 3901 // versions of the method including the current one. 3902 } else { 3903 // mark obsolete methods as such 3904 old_method->set_is_obsolete(); 3905 obsolete_count++; 3906 3907 // obsolete methods need a unique idnum so they become new entries in 3908 // the jmethodID cache in InstanceKlass 3909 assert(old_method->method_idnum() == new_method->method_idnum(), "must match"); 3910 u2 num = InstanceKlass::cast(_the_class)->next_method_idnum(); 3911 if (num != ConstMethod::UNSET_IDNUM) { 3912 old_method->set_method_idnum(num); 3913 } 3914 3915 // With tracing we try not to "yack" too much. The position of 3916 // this trace assumes there are fewer obsolete methods than 3917 // EMCP methods. 3918 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) { 3919 ResourceMark rm; 3920 log_trace(redefine, class, obsolete, mark) 3921 ("mark %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string()); 3922 } 3923 } 3924 old_method->set_is_old(); 3925 } 3926 for (int i = 0; i < _deleted_methods_length; ++i) { 3927 Method* old_method = _deleted_methods[i]; 3928 3929 assert(!old_method->has_vtable_index(), 3930 "cannot delete methods with vtable entries");; 3931 3932 // Mark all deleted methods as old, obsolete and deleted 3933 old_method->set_is_deleted(); 3934 old_method->set_is_old(); 3935 old_method->set_is_obsolete(); 3936 ++obsolete_count; 3937 // With tracing we try not to "yack" too much. The position of 3938 // this trace assumes there are fewer obsolete methods than 3939 // EMCP methods. 3940 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) { 3941 ResourceMark rm; 3942 log_trace(redefine, class, obsolete, mark) 3943 ("mark deleted %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string()); 3944 } 3945 } 3946 assert((emcp_method_count + obsolete_count) == _old_methods->length(), 3947 "sanity check"); 3948 log_trace(redefine, class, obsolete, mark)("EMCP_cnt=%d, obsolete_cnt=%d", emcp_method_count, obsolete_count); 3949 return emcp_method_count; 3950 } 3951 3952 // This internal class transfers the native function registration from old methods 3953 // to new methods. It is designed to handle both the simple case of unchanged 3954 // native methods and the complex cases of native method prefixes being added and/or 3955 // removed. 3956 // It expects only to be used during the VM_RedefineClasses op (a safepoint). 3957 // 3958 // This class is used after the new methods have been installed in "the_class". 3959 // 3960 // So, for example, the following must be handled. Where 'm' is a method and 3961 // a number followed by an underscore is a prefix. 3962 // 3963 // Old Name New Name 3964 // Simple transfer to new method m -> m 3965 // Add prefix m -> 1_m 3966 // Remove prefix 1_m -> m 3967 // Simultaneous add of prefixes m -> 3_2_1_m 3968 // Simultaneous removal of prefixes 3_2_1_m -> m 3969 // Simultaneous add and remove 1_m -> 2_m 3970 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m 3971 // 3972 class TransferNativeFunctionRegistration { 3973 private: 3974 InstanceKlass* the_class; 3975 int prefix_count; 3976 char** prefixes; 3977 3978 // Recursively search the binary tree of possibly prefixed method names. 3979 // Iteration could be used if all agents were well behaved. Full tree walk is 3980 // more resilent to agents not cleaning up intermediate methods. 3981 // Branch at each depth in the binary tree is: 3982 // (1) without the prefix. 3983 // (2) with the prefix. 3984 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...) 3985 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len, 3986 Symbol* signature) { 3987 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len); 3988 if (name_symbol != nullptr) { 3989 Method* method = the_class->lookup_method(name_symbol, signature); 3990 if (method != nullptr) { 3991 // Even if prefixed, intermediate methods must exist. 3992 if (method->is_native()) { 3993 // Wahoo, we found a (possibly prefixed) version of the method, return it. 3994 return method; 3995 } 3996 if (depth < prefix_count) { 3997 // Try applying further prefixes (other than this one). 3998 method = search_prefix_name_space(depth+1, name_str, name_len, signature); 3999 if (method != nullptr) { 4000 return method; // found 4001 } 4002 4003 // Try adding this prefix to the method name and see if it matches 4004 // another method name. 4005 char* prefix = prefixes[depth]; 4006 size_t prefix_len = strlen(prefix); 4007 size_t trial_len = name_len + prefix_len; 4008 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1); 4009 strcpy(trial_name_str, prefix); 4010 strcat(trial_name_str, name_str); 4011 method = search_prefix_name_space(depth+1, trial_name_str, trial_len, 4012 signature); 4013 if (method != nullptr) { 4014 // If found along this branch, it was prefixed, mark as such 4015 method->set_is_prefixed_native(); 4016 return method; // found 4017 } 4018 } 4019 } 4020 } 4021 return nullptr; // This whole branch bore nothing 4022 } 4023 4024 // Return the method name with old prefixes stripped away. 4025 char* method_name_without_prefixes(Method* method) { 4026 Symbol* name = method->name(); 4027 char* name_str = name->as_utf8(); 4028 4029 // Old prefixing may be defunct, strip prefixes, if any. 4030 for (int i = prefix_count-1; i >= 0; i--) { 4031 char* prefix = prefixes[i]; 4032 size_t prefix_len = strlen(prefix); 4033 if (strncmp(prefix, name_str, prefix_len) == 0) { 4034 name_str += prefix_len; 4035 } 4036 } 4037 return name_str; 4038 } 4039 4040 // Strip any prefixes off the old native method, then try to find a 4041 // (possibly prefixed) new native that matches it. 4042 Method* strip_and_search_for_new_native(Method* method) { 4043 ResourceMark rm; 4044 char* name_str = method_name_without_prefixes(method); 4045 return search_prefix_name_space(0, name_str, strlen(name_str), 4046 method->signature()); 4047 } 4048 4049 public: 4050 4051 // Construct a native method transfer processor for this class. 4052 TransferNativeFunctionRegistration(InstanceKlass* _the_class) { 4053 assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); 4054 4055 the_class = _the_class; 4056 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count); 4057 } 4058 4059 // Attempt to transfer any of the old or deleted methods that are native 4060 void transfer_registrations(Method** old_methods, int methods_length) { 4061 for (int j = 0; j < methods_length; j++) { 4062 Method* old_method = old_methods[j]; 4063 4064 if (old_method->is_native() && old_method->has_native_function()) { 4065 Method* new_method = strip_and_search_for_new_native(old_method); 4066 if (new_method != nullptr) { 4067 // Actually set the native function in the new method. 4068 // Redefine does not send events (except CFLH), certainly not this 4069 // behind the scenes re-registration. 4070 new_method->set_native_function(old_method->native_function(), 4071 !Method::native_bind_event_is_interesting); 4072 } 4073 } 4074 } 4075 } 4076 }; 4077 4078 // Don't lose the association between a native method and its JNI function. 4079 void VM_RedefineClasses::transfer_old_native_function_registrations(InstanceKlass* the_class) { 4080 TransferNativeFunctionRegistration transfer(the_class); 4081 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length); 4082 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length); 4083 } 4084 4085 // Deoptimize all compiled code that depends on the classes redefined. 4086 // 4087 // If the can_redefine_classes capability is obtained in the onload 4088 // phase or 'AlwaysRecordEvolDependencies' is true, then the compiler has 4089 // recorded all dependencies from startup. In that case we need only 4090 // deoptimize and throw away all compiled code that depends on the class. 4091 // 4092 // If can_redefine_classes is obtained sometime after the onload phase 4093 // (and 'AlwaysRecordEvolDependencies' is false) then the dependency 4094 // information may be incomplete. In that case the first call to 4095 // RedefineClasses causes all compiled code to be thrown away. As 4096 // can_redefine_classes has been obtained then all future compilations will 4097 // record dependencies so second and subsequent calls to RedefineClasses 4098 // need only throw away code that depends on the class. 4099 // 4100 4101 void VM_RedefineClasses::flush_dependent_code() { 4102 assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); 4103 assert(JvmtiExport::all_dependencies_are_recorded() || !AlwaysRecordEvolDependencies, "sanity check"); 4104 4105 DeoptimizationScope deopt_scope; 4106 4107 // This is the first redefinition, mark all the nmethods for deoptimization 4108 if (!JvmtiExport::all_dependencies_are_recorded()) { 4109 CodeCache::mark_all_nmethods_for_evol_deoptimization(&deopt_scope); 4110 log_debug(redefine, class, nmethod)("Marked all nmethods for deopt"); 4111 } else { 4112 CodeCache::mark_dependents_for_evol_deoptimization(&deopt_scope); 4113 log_debug(redefine, class, nmethod)("Marked dependent nmethods for deopt"); 4114 } 4115 4116 deopt_scope.deoptimize_marked(); 4117 4118 // From now on we know that the dependency information is complete 4119 JvmtiExport::set_all_dependencies_are_recorded(true); 4120 } 4121 4122 void VM_RedefineClasses::compute_added_deleted_matching_methods() { 4123 Method* old_method; 4124 Method* new_method; 4125 4126 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 4127 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 4128 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length()); 4129 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 4130 4131 _matching_methods_length = 0; 4132 _deleted_methods_length = 0; 4133 _added_methods_length = 0; 4134 4135 int nj = 0; 4136 int oj = 0; 4137 while (true) { 4138 if (oj >= _old_methods->length()) { 4139 if (nj >= _new_methods->length()) { 4140 break; // we've looked at everything, done 4141 } 4142 // New method at the end 4143 new_method = _new_methods->at(nj); 4144 _added_methods[_added_methods_length++] = new_method; 4145 ++nj; 4146 } else if (nj >= _new_methods->length()) { 4147 // Old method, at the end, is deleted 4148 old_method = _old_methods->at(oj); 4149 _deleted_methods[_deleted_methods_length++] = old_method; 4150 ++oj; 4151 } else { 4152 old_method = _old_methods->at(oj); 4153 new_method = _new_methods->at(nj); 4154 if (old_method->name() == new_method->name()) { 4155 if (old_method->signature() == new_method->signature()) { 4156 _matching_old_methods[_matching_methods_length ] = old_method; 4157 _matching_new_methods[_matching_methods_length++] = new_method; 4158 ++nj; 4159 ++oj; 4160 } else { 4161 // added overloaded have already been moved to the end, 4162 // so this is a deleted overloaded method 4163 _deleted_methods[_deleted_methods_length++] = old_method; 4164 ++oj; 4165 } 4166 } else { // names don't match 4167 if (old_method->name()->fast_compare(new_method->name()) > 0) { 4168 // new method 4169 _added_methods[_added_methods_length++] = new_method; 4170 ++nj; 4171 } else { 4172 // deleted method 4173 _deleted_methods[_deleted_methods_length++] = old_method; 4174 ++oj; 4175 } 4176 } 4177 } 4178 } 4179 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity"); 4180 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity"); 4181 } 4182 4183 4184 void VM_RedefineClasses::swap_annotations(InstanceKlass* the_class, 4185 InstanceKlass* scratch_class) { 4186 // Swap annotation fields values 4187 Annotations* old_annotations = the_class->annotations(); 4188 the_class->set_annotations(scratch_class->annotations()); 4189 scratch_class->set_annotations(old_annotations); 4190 } 4191 4192 4193 // Install the redefinition of a class: 4194 // - house keeping (flushing breakpoints and caches, deoptimizing 4195 // dependent compiled code) 4196 // - replacing parts in the_class with parts from scratch_class 4197 // - adding a weak reference to track the obsolete but interesting 4198 // parts of the_class 4199 // - adjusting constant pool caches and vtables in other classes 4200 // that refer to methods in the_class. These adjustments use the 4201 // ClassLoaderDataGraph::classes_do() facility which only allows 4202 // a helper method to be specified. The interesting parameters 4203 // that we would like to pass to the helper method are saved in 4204 // static global fields in the VM operation. 4205 void VM_RedefineClasses::redefine_single_class(Thread* current, jclass the_jclass, 4206 InstanceKlass* scratch_class) { 4207 4208 HandleMark hm(current); // make sure handles from this call are freed 4209 4210 if (log_is_enabled(Info, redefine, class, timer)) { 4211 _timer_rsc_phase1.start(); 4212 } 4213 4214 InstanceKlass* the_class = get_ik(the_jclass); 4215 4216 // Set a flag to control and optimize adjusting method entries 4217 _has_redefined_Object |= the_class == vmClasses::Object_klass(); 4218 4219 // Remove all breakpoints in methods of this class 4220 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints(); 4221 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class); 4222 4223 _old_methods = the_class->methods(); 4224 _new_methods = scratch_class->methods(); 4225 _the_class = the_class; 4226 compute_added_deleted_matching_methods(); 4227 update_jmethod_ids(); 4228 4229 _any_class_has_resolved_methods = the_class->has_resolved_methods() || _any_class_has_resolved_methods; 4230 4231 // Attach new constant pool to the original klass. The original 4232 // klass still refers to the old constant pool (for now). 4233 scratch_class->constants()->set_pool_holder(the_class); 4234 4235 #if 0 4236 // In theory, with constant pool merging in place we should be able 4237 // to save space by using the new, merged constant pool in place of 4238 // the old constant pool(s). By "pool(s)" I mean the constant pool in 4239 // the klass version we are replacing now and any constant pool(s) in 4240 // previous versions of klass. Nice theory, doesn't work in practice. 4241 // When this code is enabled, even simple programs throw NullPointer 4242 // exceptions. I'm guessing that this is caused by some constant pool 4243 // cache difference between the new, merged constant pool and the 4244 // constant pool that was just being used by the klass. I'm keeping 4245 // this code around to archive the idea, but the code has to remain 4246 // disabled for now. 4247 4248 // Attach each old method to the new constant pool. This can be 4249 // done here since we are past the bytecode verification and 4250 // constant pool optimization phases. 4251 for (int i = _old_methods->length() - 1; i >= 0; i--) { 4252 Method* method = _old_methods->at(i); 4253 method->set_constants(scratch_class->constants()); 4254 } 4255 4256 // NOTE: this doesn't work because you can redefine the same class in two 4257 // threads, each getting their own constant pool data appended to the 4258 // original constant pool. In order for the new methods to work when they 4259 // become old methods, they need to keep their updated copy of the constant pool. 4260 4261 { 4262 // walk all previous versions of the klass 4263 InstanceKlass *ik = the_class; 4264 PreviousVersionWalker pvw(ik); 4265 do { 4266 ik = pvw.next_previous_version(); 4267 if (ik != nullptr) { 4268 4269 // attach previous version of klass to the new constant pool 4270 ik->set_constants(scratch_class->constants()); 4271 4272 // Attach each method in the previous version of klass to the 4273 // new constant pool 4274 Array<Method*>* prev_methods = ik->methods(); 4275 for (int i = prev_methods->length() - 1; i >= 0; i--) { 4276 Method* method = prev_methods->at(i); 4277 method->set_constants(scratch_class->constants()); 4278 } 4279 } 4280 } while (ik != nullptr); 4281 } 4282 #endif 4283 4284 // Replace methods and constantpool 4285 the_class->set_methods(_new_methods); 4286 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods, 4287 // and to be able to undo operation easily. 4288 4289 Array<int>* old_ordering = the_class->method_ordering(); 4290 the_class->set_method_ordering(scratch_class->method_ordering()); 4291 scratch_class->set_method_ordering(old_ordering); 4292 4293 ConstantPool* old_constants = the_class->constants(); 4294 the_class->set_constants(scratch_class->constants()); 4295 scratch_class->set_constants(old_constants); // See the previous comment. 4296 #if 0 4297 // We are swapping the guts of "the new class" with the guts of "the 4298 // class". Since the old constant pool has just been attached to "the 4299 // new class", it seems logical to set the pool holder in the old 4300 // constant pool also. However, doing this will change the observable 4301 // class hierarchy for any old methods that are still executing. A 4302 // method can query the identity of its "holder" and this query uses 4303 // the method's constant pool link to find the holder. The change in 4304 // holding class from "the class" to "the new class" can confuse 4305 // things. 4306 // 4307 // Setting the old constant pool's holder will also cause 4308 // verification done during vtable initialization below to fail. 4309 // During vtable initialization, the vtable's class is verified to be 4310 // a subtype of the method's holder. The vtable's class is "the 4311 // class" and the method's holder is gotten from the constant pool 4312 // link in the method itself. For "the class"'s directly implemented 4313 // methods, the method holder is "the class" itself (as gotten from 4314 // the new constant pool). The check works fine in this case. The 4315 // check also works fine for methods inherited from super classes. 4316 // 4317 // Miranda methods are a little more complicated. A miranda method is 4318 // provided by an interface when the class implementing the interface 4319 // does not provide its own method. These interfaces are implemented 4320 // internally as an InstanceKlass. These special instanceKlasses 4321 // share the constant pool of the class that "implements" the 4322 // interface. By sharing the constant pool, the method holder of a 4323 // miranda method is the class that "implements" the interface. In a 4324 // non-redefine situation, the subtype check works fine. However, if 4325 // the old constant pool's pool holder is modified, then the check 4326 // fails because there is no class hierarchy relationship between the 4327 // vtable's class and "the new class". 4328 4329 old_constants->set_pool_holder(scratch_class()); 4330 #endif 4331 4332 // track number of methods that are EMCP for add_previous_version() call below 4333 int emcp_method_count = check_methods_and_mark_as_obsolete(); 4334 transfer_old_native_function_registrations(the_class); 4335 4336 if (scratch_class->get_cached_class_file() != the_class->get_cached_class_file()) { 4337 // 1. the_class doesn't have a cache yet, scratch_class does have a cache. 4338 // 2. The same class can be present twice in the scratch classes list or there 4339 // are multiple concurrent RetransformClasses calls on different threads. 4340 // the_class and scratch_class have the same cached bytes, but different buffers. 4341 // In such cases we need to deallocate one of the buffers. 4342 // 3. RedefineClasses and the_class has cached bytes from a previous transformation. 4343 // In the case we need to use class bytes from scratch_class. 4344 if (the_class->get_cached_class_file() != nullptr) { 4345 os::free(the_class->get_cached_class_file()); 4346 } 4347 the_class->set_cached_class_file(scratch_class->get_cached_class_file()); 4348 } 4349 4350 // null out in scratch class to not delete twice. The class to be redefined 4351 // always owns these bytes. 4352 scratch_class->set_cached_class_file(nullptr); 4353 4354 // Replace inner_classes 4355 Array<u2>* old_inner_classes = the_class->inner_classes(); 4356 the_class->set_inner_classes(scratch_class->inner_classes()); 4357 scratch_class->set_inner_classes(old_inner_classes); 4358 4359 // Initialize the vtable and interface table after 4360 // methods have been rewritten 4361 // no exception should happen here since we explicitly 4362 // do not check loader constraints. 4363 // compare_and_normalize_class_versions has already checked: 4364 // - classloaders unchanged, signatures unchanged 4365 // - all instanceKlasses for redefined classes reused & contents updated 4366 the_class->vtable().initialize_vtable(); 4367 the_class->itable().initialize_itable(); 4368 4369 // Update jmethodID cache if present. 4370 the_class->update_methods_jmethod_cache(); 4371 4372 // Copy the "source debug extension" attribute from new class version 4373 the_class->set_source_debug_extension( 4374 scratch_class->source_debug_extension(), 4375 scratch_class->source_debug_extension() == nullptr ? 0 : 4376 (int)strlen(scratch_class->source_debug_extension())); 4377 4378 // Use of javac -g could be different in the old and the new 4379 if (scratch_class->has_localvariable_table() != 4380 the_class->has_localvariable_table()) { 4381 the_class->set_has_localvariable_table(scratch_class->has_localvariable_table()); 4382 } 4383 4384 swap_annotations(the_class, scratch_class); 4385 4386 // Replace minor version number of class file 4387 u2 old_minor_version = the_class->constants()->minor_version(); 4388 the_class->constants()->set_minor_version(scratch_class->constants()->minor_version()); 4389 scratch_class->constants()->set_minor_version(old_minor_version); 4390 4391 // Replace major version number of class file 4392 u2 old_major_version = the_class->constants()->major_version(); 4393 the_class->constants()->set_major_version(scratch_class->constants()->major_version()); 4394 scratch_class->constants()->set_major_version(old_major_version); 4395 4396 // Replace CP indexes for class and name+type of enclosing method 4397 u2 old_class_idx = the_class->enclosing_method_class_index(); 4398 u2 old_method_idx = the_class->enclosing_method_method_index(); 4399 the_class->set_enclosing_method_indices( 4400 scratch_class->enclosing_method_class_index(), 4401 scratch_class->enclosing_method_method_index()); 4402 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx); 4403 4404 if (!the_class->has_been_redefined()) { 4405 the_class->set_has_been_redefined(); 4406 } 4407 4408 // Scratch class is unloaded but still needs cleaning, and skipping for CDS. 4409 scratch_class->set_is_scratch_class(); 4410 4411 // keep track of previous versions of this class 4412 the_class->add_previous_version(scratch_class, emcp_method_count); 4413 4414 JFR_ONLY(Jfr::on_klass_redefinition(the_class, scratch_class);) 4415 4416 _timer_rsc_phase1.stop(); 4417 if (log_is_enabled(Info, redefine, class, timer)) { 4418 _timer_rsc_phase2.start(); 4419 } 4420 4421 if (the_class->oop_map_cache() != nullptr) { 4422 // Flush references to any obsolete methods from the oop map cache 4423 // so that obsolete methods are not pinned. 4424 the_class->oop_map_cache()->flush_obsolete_entries(); 4425 } 4426 4427 increment_class_counter(the_class); 4428 4429 if (EventClassRedefinition::is_enabled()) { 4430 EventClassRedefinition event; 4431 event.set_classModificationCount(java_lang_Class::classRedefinedCount(the_class->java_mirror())); 4432 event.set_redefinedClass(the_class); 4433 event.set_redefinitionId(_id); 4434 event.commit(); 4435 } 4436 4437 { 4438 ResourceMark rm(current); 4439 // increment the classRedefinedCount field in the_class and in any 4440 // direct and indirect subclasses of the_class 4441 size_t avail_mem = 0; 4442 // Return value ignored - defaulting to 0 on failure. 4443 (void)os::available_memory(avail_mem); 4444 log_info(redefine, class, load) 4445 ("redefined name=%s, count=%d (avail_mem=%zuK)", 4446 the_class->external_name(), java_lang_Class::classRedefinedCount(the_class->java_mirror()), avail_mem >> 10); 4447 Events::log_redefinition(current, "redefined class name=%s, count=%d", 4448 the_class->external_name(), 4449 java_lang_Class::classRedefinedCount(the_class->java_mirror())); 4450 4451 } 4452 _timer_rsc_phase2.stop(); 4453 4454 } // end redefine_single_class() 4455 4456 4457 // Increment the classRedefinedCount field in the specific InstanceKlass 4458 // and in all direct and indirect subclasses. 4459 void VM_RedefineClasses::increment_class_counter(InstanceKlass* ik) { 4460 for (ClassHierarchyIterator iter(ik); !iter.done(); iter.next()) { 4461 // Only update instanceKlasses 4462 Klass* sub = iter.klass(); 4463 if (sub->is_instance_klass()) { 4464 oop class_mirror = InstanceKlass::cast(sub)->java_mirror(); 4465 Klass* class_oop = java_lang_Class::as_Klass(class_mirror); 4466 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1; 4467 java_lang_Class::set_classRedefinedCount(class_mirror, new_count); 4468 4469 if (class_oop != _the_class) { 4470 // _the_class count is printed at end of redefine_single_class() 4471 log_debug(redefine, class, subclass)("updated count in subclass=%s to %d", ik->external_name(), new_count); 4472 } 4473 } 4474 } 4475 } 4476 4477 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) { 4478 bool no_old_methods = true; // be optimistic 4479 4480 // Both array and instance classes have vtables. 4481 // a vtable should never contain old or obsolete methods 4482 ResourceMark rm(_thread); 4483 if (k->vtable_length() > 0 && 4484 !k->vtable().check_no_old_or_obsolete_entries()) { 4485 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 4486 log_trace(redefine, class, obsolete, metadata) 4487 ("klassVtable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s", 4488 k->signature_name()); 4489 k->vtable().dump_vtable(); 4490 } 4491 no_old_methods = false; 4492 } 4493 4494 if (k->is_instance_klass()) { 4495 HandleMark hm(_thread); 4496 InstanceKlass *ik = InstanceKlass::cast(k); 4497 4498 // an itable should never contain old or obsolete methods 4499 if (ik->itable_length() > 0 && 4500 !ik->itable().check_no_old_or_obsolete_entries()) { 4501 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 4502 log_trace(redefine, class, obsolete, metadata) 4503 ("klassItable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s", 4504 ik->signature_name()); 4505 ik->itable().dump_itable(); 4506 } 4507 no_old_methods = false; 4508 } 4509 4510 // the constant pool cache should never contain non-deleted old or obsolete methods 4511 if (ik->constants() != nullptr && 4512 ik->constants()->cache() != nullptr && 4513 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) { 4514 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 4515 log_trace(redefine, class, obsolete, metadata) 4516 ("cp-cache::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s", 4517 ik->signature_name()); 4518 ik->constants()->cache()->dump_cache(); 4519 } 4520 no_old_methods = false; 4521 } 4522 } 4523 4524 // print and fail guarantee if old methods are found. 4525 if (!no_old_methods) { 4526 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 4527 dump_methods(); 4528 } else { 4529 log_trace(redefine, class)("Use the '-Xlog:redefine+class*:' option " 4530 "to see more info about the following guarantee() failure."); 4531 } 4532 guarantee(false, "OLD and/or OBSOLETE method(s) found"); 4533 } 4534 } 4535 4536 u8 VM_RedefineClasses::next_id() { 4537 while (true) { 4538 u8 id = _id_counter; 4539 u8 next_id = id + 1; 4540 u8 result = Atomic::cmpxchg(&_id_counter, id, next_id); 4541 if (result == id) { 4542 return next_id; 4543 } 4544 } 4545 } 4546 4547 void VM_RedefineClasses::dump_methods() { 4548 int j; 4549 log_trace(redefine, class, dump)("_old_methods --"); 4550 for (j = 0; j < _old_methods->length(); ++j) { 4551 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4552 Method* m = _old_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)("_new_methods --"); 4560 for (j = 0; j < _new_methods->length(); ++j) { 4561 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4562 Method* m = _new_methods->at(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(&log_stream); 4567 log_stream.cr(); 4568 } 4569 log_trace(redefine, class, dump)("_matching_methods --"); 4570 for (j = 0; j < _matching_methods_length; ++j) { 4571 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4572 Method* m = _matching_old_methods[j]; 4573 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4574 m->access_flags().print_on(&log_stream); 4575 log_stream.print(" -- "); 4576 m->print_name(); 4577 log_stream.cr(); 4578 4579 m = _matching_new_methods[j]; 4580 log_stream.print(" (%5d) ", m->vtable_index()); 4581 m->access_flags().print_on(&log_stream); 4582 log_stream.cr(); 4583 } 4584 log_trace(redefine, class, dump)("_deleted_methods --"); 4585 for (j = 0; j < _deleted_methods_length; ++j) { 4586 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4587 Method* m = _deleted_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 log_trace(redefine, class, dump)("_added_methods --"); 4595 for (j = 0; j < _added_methods_length; ++j) { 4596 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4597 Method* m = _added_methods[j]; 4598 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4599 m->access_flags().print_on(&log_stream); 4600 log_stream.print(" -- "); 4601 m->print_name(&log_stream); 4602 log_stream.cr(); 4603 } 4604 } 4605 4606 void VM_RedefineClasses::print_on_error(outputStream* st) const { 4607 VM_Operation::print_on_error(st); 4608 if (_the_class != nullptr) { 4609 ResourceMark rm; 4610 st->print_cr(", redefining class %s", _the_class->external_name()); 4611 } 4612 }