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/metadataOnStackMark.hpp" 32 #include "classfile/symbolTable.hpp" 33 #include "classfile/klassFactory.hpp" 34 #include "classfile/verifier.hpp" 35 #include "classfile/vmClasses.hpp" 36 #include "classfile/vmSymbols.hpp" 37 #include "code/codeCache.hpp" 38 #include "compiler/compileBroker.hpp" 39 #include "interpreter/oopMapCache.hpp" 40 #include "interpreter/rewriter.hpp" 41 #include "jfr/jfrEvents.hpp" 42 #include "logging/logStream.hpp" 43 #include "memory/metadataFactory.hpp" 44 #include "memory/resourceArea.hpp" 45 #include "memory/universe.hpp" 46 #include "oops/annotations.hpp" 47 #include "oops/constantPool.hpp" 48 #include "oops/fieldStreams.inline.hpp" 49 #include "oops/klass.inline.hpp" 50 #include "oops/klassVtable.hpp" 51 #include "oops/method.hpp" 52 #include "oops/oop.inline.hpp" 53 #include "oops/recordComponent.hpp" 54 #include "prims/jvmtiImpl.hpp" 55 #include "prims/jvmtiRedefineClasses.hpp" 56 #include "prims/jvmtiThreadState.inline.hpp" 57 #include "prims/resolvedMethodTable.hpp" 58 #include "prims/methodComparator.hpp" 59 #include "runtime/atomic.hpp" 60 #include "runtime/deoptimization.hpp" 61 #include "runtime/handles.inline.hpp" 62 #include "runtime/jniHandles.inline.hpp" 63 #include "runtime/relocator.hpp" 64 #include "runtime/safepointVerifiers.hpp" 65 #include "utilities/bitMap.inline.hpp" 66 #include "utilities/checkedCast.hpp" 67 #include "utilities/events.hpp" 68 #include "utilities/macros.hpp" 69 70 Array<Method*>* VM_RedefineClasses::_old_methods = nullptr; 71 Array<Method*>* VM_RedefineClasses::_new_methods = nullptr; 72 Method** VM_RedefineClasses::_matching_old_methods = nullptr; 73 Method** VM_RedefineClasses::_matching_new_methods = nullptr; 74 Method** VM_RedefineClasses::_deleted_methods = nullptr; 75 Method** VM_RedefineClasses::_added_methods = nullptr; 76 int VM_RedefineClasses::_matching_methods_length = 0; 77 int VM_RedefineClasses::_deleted_methods_length = 0; 78 int VM_RedefineClasses::_added_methods_length = 0; 79 80 // This flag is global as the constructor does not reset it: 81 bool VM_RedefineClasses::_has_redefined_Object = false; 82 u8 VM_RedefineClasses::_id_counter = 0; 83 84 VM_RedefineClasses::VM_RedefineClasses(jint class_count, 85 const jvmtiClassDefinition *class_defs, 86 JvmtiClassLoadKind class_load_kind) { 87 _class_count = class_count; 88 _class_defs = class_defs; 89 _class_load_kind = class_load_kind; 90 _any_class_has_resolved_methods = false; 91 _res = JVMTI_ERROR_NONE; 92 _the_class = nullptr; 93 _id = next_id(); 94 } 95 96 static inline InstanceKlass* get_ik(jclass def) { 97 oop mirror = JNIHandles::resolve_non_null(def); 98 return InstanceKlass::cast(java_lang_Class::as_Klass(mirror)); 99 } 100 101 // If any of the classes are being redefined, wait 102 // Parallel constant pool merging leads to indeterminate constant pools. 103 void VM_RedefineClasses::lock_classes() { 104 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current()); 105 GrowableArray<Klass*>* redef_classes = state->get_classes_being_redefined(); 106 107 MonitorLocker ml(RedefineClasses_lock); 108 109 if (redef_classes == nullptr) { 110 redef_classes = new (mtClass) GrowableArray<Klass*>(1, mtClass); 111 state->set_classes_being_redefined(redef_classes); 112 } 113 114 bool has_redefined; 115 do { 116 has_redefined = false; 117 // Go through classes each time until none are being redefined. Skip 118 // the ones that are being redefined by this thread currently. Class file 119 // load hook event may trigger new class redefine when we are redefining 120 // a class (after lock_classes()). 121 for (int i = 0; i < _class_count; i++) { 122 InstanceKlass* ik = get_ik(_class_defs[i].klass); 123 // Check if we are currently redefining the class in this thread already. 124 if (redef_classes->contains(ik)) { 125 assert(ik->is_being_redefined(), "sanity"); 126 } else { 127 if (ik->is_being_redefined()) { 128 ml.wait(); 129 has_redefined = true; 130 break; // for loop 131 } 132 } 133 } 134 } while (has_redefined); 135 136 for (int i = 0; i < _class_count; i++) { 137 InstanceKlass* ik = get_ik(_class_defs[i].klass); 138 redef_classes->push(ik); // Add to the _classes_being_redefined list 139 ik->set_is_being_redefined(true); 140 } 141 ml.notify_all(); 142 } 143 144 void VM_RedefineClasses::unlock_classes() { 145 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current()); 146 GrowableArray<Klass*>* redef_classes = state->get_classes_being_redefined(); 147 assert(redef_classes != nullptr, "_classes_being_redefined is not allocated"); 148 149 MonitorLocker ml(RedefineClasses_lock); 150 151 for (int i = _class_count - 1; i >= 0; i--) { 152 InstanceKlass* def_ik = get_ik(_class_defs[i].klass); 153 if (redef_classes->length() > 0) { 154 // Remove the class from _classes_being_redefined list 155 Klass* k = redef_classes->pop(); 156 assert(def_ik == k, "unlocking wrong class"); 157 } 158 assert(def_ik->is_being_redefined(), 159 "should be being redefined to get here"); 160 161 // Unlock after we finish all redefines for this class within 162 // the thread. Same class can be pushed to the list multiple 163 // times (not more than once by each recursive redefinition). 164 if (!redef_classes->contains(def_ik)) { 165 def_ik->set_is_being_redefined(false); 166 } 167 } 168 ml.notify_all(); 169 } 170 171 bool VM_RedefineClasses::doit_prologue() { 172 if (_class_count == 0) { 173 _res = JVMTI_ERROR_NONE; 174 return false; 175 } 176 if (_class_defs == nullptr) { 177 _res = JVMTI_ERROR_NULL_POINTER; 178 return false; 179 } 180 181 for (int i = 0; i < _class_count; i++) { 182 if (_class_defs[i].klass == nullptr) { 183 _res = JVMTI_ERROR_INVALID_CLASS; 184 return false; 185 } 186 if (_class_defs[i].class_byte_count == 0) { 187 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT; 188 return false; 189 } 190 if (_class_defs[i].class_bytes == nullptr) { 191 _res = JVMTI_ERROR_NULL_POINTER; 192 return false; 193 } 194 195 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass); 196 // classes for primitives, arrays, and hidden classes 197 // cannot be redefined. 198 if (!is_modifiable_class(mirror)) { 199 _res = JVMTI_ERROR_UNMODIFIABLE_CLASS; 200 return false; 201 } 202 } 203 204 // Start timer after all the sanity checks; not quite accurate, but 205 // better than adding a bunch of stop() calls. 206 if (log_is_enabled(Info, redefine, class, timer)) { 207 _timer_vm_op_prologue.start(); 208 } 209 210 lock_classes(); 211 // We first load new class versions in the prologue, because somewhere down the 212 // call chain it is required that the current thread is a Java thread. 213 _res = load_new_class_versions(); 214 if (_res != JVMTI_ERROR_NONE) { 215 // free any successfully created classes, since none are redefined 216 for (int i = 0; i < _class_count; i++) { 217 if (_scratch_classes[i] != nullptr) { 218 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data(); 219 // Free the memory for this class at class unloading time. Not before 220 // because CMS might think this is still live. 221 InstanceKlass* ik = get_ik(_class_defs[i].klass); 222 if (ik->get_cached_class_file() == _scratch_classes[i]->get_cached_class_file()) { 223 // Don't double-free cached_class_file copied from the original class if error. 224 _scratch_classes[i]->set_cached_class_file(nullptr); 225 } 226 cld->add_to_deallocate_list(InstanceKlass::cast(_scratch_classes[i])); 227 } 228 } 229 // Free os::malloc allocated memory in load_new_class_version. 230 os::free(_scratch_classes); 231 _timer_vm_op_prologue.stop(); 232 unlock_classes(); 233 return false; 234 } 235 236 _timer_vm_op_prologue.stop(); 237 return true; 238 } 239 240 void VM_RedefineClasses::doit() { 241 Thread* current = Thread::current(); 242 243 if (log_is_enabled(Info, redefine, class, timer)) { 244 _timer_vm_op_doit.start(); 245 } 246 247 #if INCLUDE_CDS 248 if (CDSConfig::is_using_archive()) { 249 // Sharing is enabled so we remap the shared readonly space to 250 // shared readwrite, private just in case we need to redefine 251 // a shared class. We do the remap during the doit() phase of 252 // the safepoint to be safer. 253 if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) { 254 log_info(redefine, class, load)("failed to remap shared readonly space to readwrite, private"); 255 _res = JVMTI_ERROR_INTERNAL; 256 _timer_vm_op_doit.stop(); 257 return; 258 } 259 } 260 #endif 261 262 // Mark methods seen on stack and everywhere else so old methods are not 263 // cleaned up if they're on the stack. 264 MetadataOnStackMark md_on_stack(/*walk_all_metadata*/true, /*redefinition_walk*/true); 265 HandleMark hm(current); // make sure any handles created are deleted 266 // before the stack walk again. 267 268 for (int i = 0; i < _class_count; i++) { 269 redefine_single_class(current, _class_defs[i].klass, _scratch_classes[i]); 270 } 271 272 // Flush all compiled code that depends on the classes redefined. 273 flush_dependent_code(); 274 275 // Adjust constantpool caches and vtables for all classes 276 // that reference methods of the evolved classes. 277 // Have to do this after all classes are redefined and all methods that 278 // are redefined are marked as old. 279 AdjustAndCleanMetadata adjust_and_clean_metadata(current); 280 ClassLoaderDataGraph::classes_do(&adjust_and_clean_metadata); 281 282 // JSR-292 support 283 if (_any_class_has_resolved_methods) { 284 bool trace_name_printed = false; 285 ResolvedMethodTable::adjust_method_entries(&trace_name_printed); 286 } 287 288 // Increment flag indicating that some invariants are no longer true. 289 // See jvmtiExport.hpp for detailed explanation. 290 JvmtiExport::increment_redefinition_count(); 291 292 // check_class() is optionally called for product bits, but is 293 // always called for non-product bits. 294 #ifdef PRODUCT 295 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 296 #endif 297 log_trace(redefine, class, obsolete, metadata)("calling check_class"); 298 CheckClass check_class(current); 299 ClassLoaderDataGraph::classes_do(&check_class); 300 #ifdef PRODUCT 301 } 302 #endif 303 304 // Clean up any metadata now unreferenced while MetadataOnStackMark is set. 305 ClassLoaderDataGraph::clean_deallocate_lists(false); 306 307 _timer_vm_op_doit.stop(); 308 } 309 310 void VM_RedefineClasses::doit_epilogue() { 311 unlock_classes(); 312 313 // Free os::malloc allocated memory. 314 os::free(_scratch_classes); 315 316 // Reset the_class to null for error printing. 317 _the_class = nullptr; 318 319 if (log_is_enabled(Info, redefine, class, timer)) { 320 // Used to have separate timers for "doit" and "all", but the timer 321 // overhead skewed the measurements. 322 julong doit_time = _timer_vm_op_doit.milliseconds(); 323 julong all_time = _timer_vm_op_prologue.milliseconds() + doit_time; 324 325 log_info(redefine, class, timer) 326 ("vm_op: all=" JULONG_FORMAT " prologue=" JULONG_FORMAT " doit=" JULONG_FORMAT, 327 all_time, (julong)_timer_vm_op_prologue.milliseconds(), doit_time); 328 log_info(redefine, class, timer) 329 ("redefine_single_class: phase1=" JULONG_FORMAT " phase2=" JULONG_FORMAT, 330 (julong)_timer_rsc_phase1.milliseconds(), (julong)_timer_rsc_phase2.milliseconds()); 331 } 332 } 333 334 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) { 335 // classes for primitives cannot be redefined 336 if (java_lang_Class::is_primitive(klass_mirror)) { 337 return false; 338 } 339 Klass* k = java_lang_Class::as_Klass(klass_mirror); 340 // classes for arrays cannot be redefined 341 if (k == nullptr || !k->is_instance_klass()) { 342 return false; 343 } 344 345 // Cannot redefine or retransform a hidden class. 346 if (InstanceKlass::cast(k)->is_hidden()) { 347 return false; 348 } 349 if (InstanceKlass::cast(k) == vmClasses::Continuation_klass()) { 350 // Don't redefine Continuation class. See 8302779. 351 return false; 352 } 353 return true; 354 } 355 356 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p 357 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For 358 // direct CP entries, there is just the current entry to append. For 359 // indirect and double-indirect CP entries, there are zero or more 360 // referenced CP entries along with the current entry to append. 361 // Indirect and double-indirect CP entries are handled by recursive 362 // calls to append_entry() as needed. The referenced CP entries are 363 // always appended to *merge_cp_p before the referee CP entry. These 364 // referenced CP entries may already exist in *merge_cp_p in which case 365 // there is nothing extra to append and only the current entry is 366 // appended. 367 void VM_RedefineClasses::append_entry(const constantPoolHandle& scratch_cp, 368 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) { 369 370 // append is different depending on entry tag type 371 switch (scratch_cp->tag_at(scratch_i).value()) { 372 373 // The old verifier is implemented outside the VM. It loads classes, 374 // but does not resolve constant pool entries directly so we never 375 // see Class entries here with the old verifier. Similarly the old 376 // verifier does not like Class entries in the input constant pool. 377 // The split-verifier is implemented in the VM so it can optionally 378 // and directly resolve constant pool entries to load classes. The 379 // split-verifier can accept either Class entries or UnresolvedClass 380 // entries in the input constant pool. We revert the appended copy 381 // back to UnresolvedClass so that either verifier will be happy 382 // with the constant pool entry. 383 // 384 // this is an indirect CP entry so it needs special handling 385 case JVM_CONSTANT_Class: 386 case JVM_CONSTANT_UnresolvedClass: 387 { 388 int name_i = scratch_cp->klass_name_index_at(scratch_i); 389 int new_name_i = find_or_append_indirect_entry(scratch_cp, name_i, merge_cp_p, 390 merge_cp_length_p); 391 392 if (new_name_i != name_i) { 393 log_trace(redefine, class, constantpool) 394 ("Class entry@%d name_index change: %d to %d", 395 *merge_cp_length_p, name_i, new_name_i); 396 } 397 398 (*merge_cp_p)->temp_unresolved_klass_at_put(*merge_cp_length_p, new_name_i); 399 if (scratch_i != *merge_cp_length_p) { 400 // The new entry in *merge_cp_p is at a different index than 401 // the new entry in scratch_cp so we need to map the index values. 402 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 403 } 404 (*merge_cp_length_p)++; 405 } break; 406 407 // these are direct CP entries so they can be directly appended, 408 // but double and long take two constant pool entries 409 case JVM_CONSTANT_Double: // fall through 410 case JVM_CONSTANT_Long: 411 { 412 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p); 413 414 if (scratch_i != *merge_cp_length_p) { 415 // The new entry in *merge_cp_p is at a different index than 416 // the new entry in scratch_cp so we need to map the index values. 417 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 418 } 419 (*merge_cp_length_p) += 2; 420 } break; 421 422 // these are direct CP entries so they can be directly appended 423 case JVM_CONSTANT_Float: // fall through 424 case JVM_CONSTANT_Integer: // fall through 425 case JVM_CONSTANT_Utf8: // fall through 426 427 // This was an indirect CP entry, but it has been changed into 428 // Symbol*s so this entry can be directly appended. 429 case JVM_CONSTANT_String: // fall through 430 { 431 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p); 432 433 if (scratch_i != *merge_cp_length_p) { 434 // The new entry in *merge_cp_p is at a different index than 435 // the new entry in scratch_cp so we need to map the index values. 436 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 437 } 438 (*merge_cp_length_p)++; 439 } break; 440 441 // this is an indirect CP entry so it needs special handling 442 case JVM_CONSTANT_NameAndType: 443 { 444 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i); 445 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p, 446 merge_cp_length_p); 447 448 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i); 449 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i, 450 merge_cp_p, merge_cp_length_p); 451 452 // If the referenced entries already exist in *merge_cp_p, then 453 // both new_name_ref_i and new_signature_ref_i will both be 0. 454 // In that case, all we are appending is the current entry. 455 if (new_name_ref_i != name_ref_i) { 456 log_trace(redefine, class, constantpool) 457 ("NameAndType entry@%d name_ref_index change: %d to %d", 458 *merge_cp_length_p, name_ref_i, new_name_ref_i); 459 } 460 if (new_signature_ref_i != signature_ref_i) { 461 log_trace(redefine, class, constantpool) 462 ("NameAndType entry@%d signature_ref_index change: %d to %d", 463 *merge_cp_length_p, signature_ref_i, new_signature_ref_i); 464 } 465 466 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p, 467 new_name_ref_i, new_signature_ref_i); 468 if (scratch_i != *merge_cp_length_p) { 469 // The new entry in *merge_cp_p is at a different index than 470 // the new entry in scratch_cp so we need to map the index values. 471 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 472 } 473 (*merge_cp_length_p)++; 474 } break; 475 476 // this is a double-indirect CP entry so it needs special handling 477 case JVM_CONSTANT_Fieldref: // fall through 478 case JVM_CONSTANT_InterfaceMethodref: // fall through 479 case JVM_CONSTANT_Methodref: 480 { 481 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i); 482 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i, 483 merge_cp_p, merge_cp_length_p); 484 485 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i); 486 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i, 487 merge_cp_p, merge_cp_length_p); 488 489 const char *entry_name = nullptr; 490 switch (scratch_cp->tag_at(scratch_i).value()) { 491 case JVM_CONSTANT_Fieldref: 492 entry_name = "Fieldref"; 493 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i, 494 new_name_and_type_ref_i); 495 break; 496 case JVM_CONSTANT_InterfaceMethodref: 497 entry_name = "IFMethodref"; 498 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p, 499 new_klass_ref_i, new_name_and_type_ref_i); 500 break; 501 case JVM_CONSTANT_Methodref: 502 entry_name = "Methodref"; 503 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i, 504 new_name_and_type_ref_i); 505 break; 506 default: 507 guarantee(false, "bad switch"); 508 break; 509 } 510 511 if (klass_ref_i != new_klass_ref_i) { 512 log_trace(redefine, class, constantpool) 513 ("%s entry@%d class_index changed: %d to %d", entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i); 514 } 515 if (name_and_type_ref_i != new_name_and_type_ref_i) { 516 log_trace(redefine, class, constantpool) 517 ("%s entry@%d name_and_type_index changed: %d to %d", 518 entry_name, *merge_cp_length_p, name_and_type_ref_i, new_name_and_type_ref_i); 519 } 520 521 if (scratch_i != *merge_cp_length_p) { 522 // The new entry in *merge_cp_p is at a different index than 523 // the new entry in scratch_cp so we need to map the index values. 524 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 525 } 526 (*merge_cp_length_p)++; 527 } break; 528 529 // this is an indirect CP entry so it needs special handling 530 case JVM_CONSTANT_MethodType: 531 { 532 int ref_i = scratch_cp->method_type_index_at(scratch_i); 533 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p, 534 merge_cp_length_p); 535 if (new_ref_i != ref_i) { 536 log_trace(redefine, class, constantpool) 537 ("MethodType entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i); 538 } 539 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i); 540 if (scratch_i != *merge_cp_length_p) { 541 // The new entry in *merge_cp_p is at a different index than 542 // the new entry in scratch_cp so we need to map the index values. 543 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 544 } 545 (*merge_cp_length_p)++; 546 } break; 547 548 // this is an indirect CP entry so it needs special handling 549 case JVM_CONSTANT_MethodHandle: 550 { 551 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i); 552 int ref_i = scratch_cp->method_handle_index_at(scratch_i); 553 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p, 554 merge_cp_length_p); 555 if (new_ref_i != ref_i) { 556 log_trace(redefine, class, constantpool) 557 ("MethodHandle entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i); 558 } 559 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i); 560 if (scratch_i != *merge_cp_length_p) { 561 // The new entry in *merge_cp_p is at a different index than 562 // the new entry in scratch_cp so we need to map the index values. 563 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 564 } 565 (*merge_cp_length_p)++; 566 } break; 567 568 // this is an indirect CP entry so it needs special handling 569 case JVM_CONSTANT_Dynamic: // fall through 570 case JVM_CONSTANT_InvokeDynamic: 571 { 572 // Index of the bootstrap specifier in the operands array 573 int old_bs_i = scratch_cp->bootstrap_methods_attribute_index(scratch_i); 574 int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p, 575 merge_cp_length_p); 576 // The bootstrap method NameAndType_info index 577 int old_ref_i = scratch_cp->bootstrap_name_and_type_ref_index_at(scratch_i); 578 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p, 579 merge_cp_length_p); 580 if (new_bs_i != old_bs_i) { 581 log_trace(redefine, class, constantpool) 582 ("Dynamic entry@%d bootstrap_method_attr_index change: %d to %d", 583 *merge_cp_length_p, old_bs_i, new_bs_i); 584 } 585 if (new_ref_i != old_ref_i) { 586 log_trace(redefine, class, constantpool) 587 ("Dynamic entry@%d name_and_type_index change: %d to %d", *merge_cp_length_p, old_ref_i, new_ref_i); 588 } 589 590 if (scratch_cp->tag_at(scratch_i).is_dynamic_constant()) 591 (*merge_cp_p)->dynamic_constant_at_put(*merge_cp_length_p, new_bs_i, new_ref_i); 592 else 593 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i); 594 if (scratch_i != *merge_cp_length_p) { 595 // The new entry in *merge_cp_p is at a different index than 596 // the new entry in scratch_cp so we need to map the index values. 597 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 598 } 599 (*merge_cp_length_p)++; 600 } break; 601 602 // At this stage, Class or UnresolvedClass could be in scratch_cp, but not 603 // ClassIndex 604 case JVM_CONSTANT_ClassIndex: // fall through 605 606 // Invalid is used as the tag for the second constant pool entry 607 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should 608 // not be seen by itself. 609 case JVM_CONSTANT_Invalid: // fall through 610 611 // At this stage, String could be here, but not StringIndex 612 case JVM_CONSTANT_StringIndex: // fall through 613 614 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be 615 // here 616 case JVM_CONSTANT_UnresolvedClassInError: // fall through 617 618 default: 619 { 620 // leave a breadcrumb 621 jbyte bad_value = scratch_cp->tag_at(scratch_i).value(); 622 ShouldNotReachHere(); 623 } break; 624 } // end switch tag value 625 } // end append_entry() 626 627 628 u2 VM_RedefineClasses::find_or_append_indirect_entry(const constantPoolHandle& scratch_cp, 629 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) { 630 631 int new_ref_i = ref_i; 632 bool match = (ref_i < *merge_cp_length_p) && 633 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i); 634 635 if (!match) { 636 // forward reference in *merge_cp_p or not a direct match 637 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p); 638 if (found_i != 0) { 639 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree"); 640 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry. 641 new_ref_i = found_i; 642 map_index(scratch_cp, ref_i, found_i); 643 } else { 644 // no match found so we have to append this entry to *merge_cp_p 645 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p); 646 // The above call to append_entry() can only append one entry 647 // so the post call query of *merge_cp_length_p is only for 648 // the sake of consistency. 649 new_ref_i = *merge_cp_length_p - 1; 650 } 651 } 652 653 // constant pool indices are u2, unless the merged constant pool overflows which 654 // we don't check for. 655 return checked_cast<u2>(new_ref_i); 656 } // end find_or_append_indirect_entry() 657 658 659 // Append a bootstrap specifier into the merge_cp operands that is semantically equal 660 // to the scratch_cp operands bootstrap specifier passed by the old_bs_i index. 661 // Recursively append new merge_cp entries referenced by the new bootstrap specifier. 662 void VM_RedefineClasses::append_operand(const constantPoolHandle& scratch_cp, int old_bs_i, 663 constantPoolHandle *merge_cp_p, int *merge_cp_length_p) { 664 665 u2 old_ref_i = scratch_cp->operand_bootstrap_method_ref_index_at(old_bs_i); 666 u2 new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p, 667 merge_cp_length_p); 668 if (new_ref_i != old_ref_i) { 669 log_trace(redefine, class, constantpool) 670 ("operands entry@%d bootstrap method ref_index change: %d to %d", _operands_cur_length, old_ref_i, new_ref_i); 671 } 672 673 Array<u2>* merge_ops = (*merge_cp_p)->operands(); 674 int new_bs_i = _operands_cur_length; 675 // We have _operands_cur_length == 0 when the merge_cp operands is empty yet. 676 // However, the operand_offset_at(0) was set in the extend_operands() call. 677 int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0) 678 : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1); 679 u2 argc = scratch_cp->operand_argument_count_at(old_bs_i); 680 681 ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base); 682 merge_ops->at_put(new_base++, new_ref_i); 683 merge_ops->at_put(new_base++, argc); 684 685 for (int i = 0; i < argc; i++) { 686 u2 old_arg_ref_i = scratch_cp->operand_argument_index_at(old_bs_i, i); 687 u2 new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p, 688 merge_cp_length_p); 689 merge_ops->at_put(new_base++, new_arg_ref_i); 690 if (new_arg_ref_i != old_arg_ref_i) { 691 log_trace(redefine, class, constantpool) 692 ("operands entry@%d bootstrap method argument ref_index change: %d to %d", 693 _operands_cur_length, old_arg_ref_i, new_arg_ref_i); 694 } 695 } 696 if (old_bs_i != _operands_cur_length) { 697 // The bootstrap specifier in *merge_cp_p is at a different index than 698 // that in scratch_cp so we need to map the index values. 699 map_operand_index(old_bs_i, new_bs_i); 700 } 701 _operands_cur_length++; 702 } // end append_operand() 703 704 705 int VM_RedefineClasses::find_or_append_operand(const constantPoolHandle& scratch_cp, 706 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) { 707 708 int new_bs_i = old_bs_i; // bootstrap specifier index 709 bool match = (old_bs_i < _operands_cur_length) && 710 scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i); 711 712 if (!match) { 713 // forward reference in *merge_cp_p or not a direct match 714 int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p, 715 _operands_cur_length); 716 if (found_i != -1) { 717 guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree"); 718 // found a matching operand somewhere else in *merge_cp_p so just need a mapping 719 new_bs_i = found_i; 720 map_operand_index(old_bs_i, found_i); 721 } else { 722 // no match found so we have to append this bootstrap specifier to *merge_cp_p 723 append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p); 724 new_bs_i = _operands_cur_length - 1; 725 } 726 } 727 return new_bs_i; 728 } // end find_or_append_operand() 729 730 731 void VM_RedefineClasses::finalize_operands_merge(const constantPoolHandle& merge_cp, TRAPS) { 732 if (merge_cp->operands() == nullptr) { 733 return; 734 } 735 // Shrink the merge_cp operands 736 merge_cp->shrink_operands(_operands_cur_length, CHECK); 737 738 if (log_is_enabled(Trace, redefine, class, constantpool)) { 739 // don't want to loop unless we are tracing 740 int count = 0; 741 for (int i = 1; i < _operands_index_map_p->length(); i++) { 742 int value = _operands_index_map_p->at(i); 743 if (value != -1) { 744 log_trace(redefine, class, constantpool)("operands_index_map[%d]: old=%d new=%d", count, i, value); 745 count++; 746 } 747 } 748 } 749 // Clean-up 750 _operands_index_map_p = nullptr; 751 _operands_cur_length = 0; 752 _operands_index_map_count = 0; 753 } // end finalize_operands_merge() 754 755 // Symbol* comparator for qsort 756 // The caller must have an active ResourceMark. 757 static int symcmp(const void* a, const void* b) { 758 char* astr = (*(Symbol**)a)->as_C_string(); 759 char* bstr = (*(Symbol**)b)->as_C_string(); 760 return strcmp(astr, bstr); 761 } 762 763 // The caller must have an active ResourceMark. 764 static jvmtiError check_attribute_arrays(const char* attr_name, 765 InstanceKlass* the_class, InstanceKlass* scratch_class, 766 Array<u2>* the_array, Array<u2>* scr_array) { 767 bool the_array_exists = the_array != Universe::the_empty_short_array(); 768 bool scr_array_exists = scr_array != Universe::the_empty_short_array(); 769 770 int array_len = the_array->length(); 771 if (the_array_exists && scr_array_exists) { 772 if (array_len != scr_array->length()) { 773 log_trace(redefine, class) 774 ("redefined class %s attribute change error: %s len=%d changed to len=%d", 775 the_class->external_name(), attr_name, array_len, scr_array->length()); 776 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 777 } 778 779 // The order of entries in the attribute array is not specified so we 780 // have to explicitly check for the same contents. We do this by copying 781 // the referenced symbols into their own arrays, sorting them and then 782 // comparing each element pair. 783 784 Symbol** the_syms = NEW_RESOURCE_ARRAY_RETURN_NULL(Symbol*, array_len); 785 Symbol** scr_syms = NEW_RESOURCE_ARRAY_RETURN_NULL(Symbol*, array_len); 786 787 if (the_syms == nullptr || scr_syms == nullptr) { 788 return JVMTI_ERROR_OUT_OF_MEMORY; 789 } 790 791 for (int i = 0; i < array_len; i++) { 792 int the_cp_index = the_array->at(i); 793 int scr_cp_index = scr_array->at(i); 794 the_syms[i] = the_class->constants()->klass_name_at(the_cp_index); 795 scr_syms[i] = scratch_class->constants()->klass_name_at(scr_cp_index); 796 } 797 798 qsort(the_syms, array_len, sizeof(Symbol*), symcmp); 799 qsort(scr_syms, array_len, sizeof(Symbol*), symcmp); 800 801 for (int i = 0; i < array_len; i++) { 802 if (the_syms[i] != scr_syms[i]) { 803 log_info(redefine, class) 804 ("redefined class %s attribute change error: %s[%d]: %s changed to %s", 805 the_class->external_name(), attr_name, i, 806 the_syms[i]->as_C_string(), scr_syms[i]->as_C_string()); 807 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 808 } 809 } 810 } else if (the_array_exists ^ scr_array_exists) { 811 const char* action_str = (the_array_exists) ? "removed" : "added"; 812 log_info(redefine, class) 813 ("redefined class %s attribute change error: %s attribute %s", 814 the_class->external_name(), attr_name, action_str); 815 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 816 } 817 return JVMTI_ERROR_NONE; 818 } 819 820 static jvmtiError check_nest_attributes(InstanceKlass* the_class, 821 InstanceKlass* scratch_class) { 822 // Check whether the class NestHost attribute has been changed. 823 Thread* thread = Thread::current(); 824 ResourceMark rm(thread); 825 u2 the_nest_host_idx = the_class->nest_host_index(); 826 u2 scr_nest_host_idx = scratch_class->nest_host_index(); 827 828 if (the_nest_host_idx != 0 && scr_nest_host_idx != 0) { 829 Symbol* the_sym = the_class->constants()->klass_name_at(the_nest_host_idx); 830 Symbol* scr_sym = scratch_class->constants()->klass_name_at(scr_nest_host_idx); 831 if (the_sym != scr_sym) { 832 log_info(redefine, class, nestmates) 833 ("redefined class %s attribute change error: NestHost class: %s replaced with: %s", 834 the_class->external_name(), the_sym->as_C_string(), scr_sym->as_C_string()); 835 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 836 } 837 } else if ((the_nest_host_idx == 0) ^ (scr_nest_host_idx == 0)) { 838 const char* action_str = (the_nest_host_idx != 0) ? "removed" : "added"; 839 log_info(redefine, class, nestmates) 840 ("redefined class %s attribute change error: NestHost attribute %s", 841 the_class->external_name(), action_str); 842 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 843 } 844 845 // Check whether the class NestMembers attribute has been changed. 846 return check_attribute_arrays("NestMembers", 847 the_class, scratch_class, 848 the_class->nest_members(), 849 scratch_class->nest_members()); 850 } 851 852 // Return an error status if the class Record attribute was changed. 853 static jvmtiError check_record_attribute(InstanceKlass* the_class, InstanceKlass* scratch_class) { 854 // Get lists of record components. 855 Array<RecordComponent*>* the_record = the_class->record_components(); 856 Array<RecordComponent*>* scr_record = scratch_class->record_components(); 857 bool the_record_exists = the_record != nullptr; 858 bool scr_record_exists = scr_record != nullptr; 859 860 if (the_record_exists && scr_record_exists) { 861 int the_num_components = the_record->length(); 862 int scr_num_components = scr_record->length(); 863 if (the_num_components != scr_num_components) { 864 log_info(redefine, class, record) 865 ("redefined class %s attribute change error: Record num_components=%d changed to num_components=%d", 866 the_class->external_name(), the_num_components, scr_num_components); 867 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 868 } 869 870 // Compare each field in each record component. 871 ConstantPool* the_cp = the_class->constants(); 872 ConstantPool* scr_cp = scratch_class->constants(); 873 for (int x = 0; x < the_num_components; x++) { 874 RecordComponent* the_component = the_record->at(x); 875 RecordComponent* scr_component = scr_record->at(x); 876 const Symbol* const the_name = the_cp->symbol_at(the_component->name_index()); 877 const Symbol* const scr_name = scr_cp->symbol_at(scr_component->name_index()); 878 const Symbol* const the_descr = the_cp->symbol_at(the_component->descriptor_index()); 879 const Symbol* const scr_descr = scr_cp->symbol_at(scr_component->descriptor_index()); 880 if (the_name != scr_name || the_descr != scr_descr) { 881 log_info(redefine, class, record) 882 ("redefined class %s attribute change error: Record name_index, descriptor_index, and/or attributes_count changed", 883 the_class->external_name()); 884 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 885 } 886 887 int the_gen_sig = the_component->generic_signature_index(); 888 int scr_gen_sig = scr_component->generic_signature_index(); 889 const Symbol* const the_gen_sig_sym = (the_gen_sig == 0 ? nullptr : 890 the_cp->symbol_at(the_component->generic_signature_index())); 891 const Symbol* const scr_gen_sig_sym = (scr_gen_sig == 0 ? nullptr : 892 scr_cp->symbol_at(scr_component->generic_signature_index())); 893 if (the_gen_sig_sym != scr_gen_sig_sym) { 894 log_info(redefine, class, record) 895 ("redefined class %s attribute change error: Record generic_signature attribute changed", 896 the_class->external_name()); 897 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 898 } 899 900 // It's okay if a record component's annotations were changed. 901 } 902 903 } else if (the_record_exists ^ scr_record_exists) { 904 const char* action_str = (the_record_exists) ? "removed" : "added"; 905 log_info(redefine, class, record) 906 ("redefined class %s attribute change error: Record attribute %s", 907 the_class->external_name(), action_str); 908 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 909 } 910 911 return JVMTI_ERROR_NONE; 912 } 913 914 915 static jvmtiError check_permitted_subclasses_attribute(InstanceKlass* the_class, 916 InstanceKlass* scratch_class) { 917 Thread* thread = Thread::current(); 918 ResourceMark rm(thread); 919 920 // Check whether the class PermittedSubclasses attribute has been changed. 921 return check_attribute_arrays("PermittedSubclasses", 922 the_class, scratch_class, 923 the_class->permitted_subclasses(), 924 scratch_class->permitted_subclasses()); 925 } 926 927 static bool can_add_or_delete(Method* m) { 928 // Compatibility mode 929 return (AllowRedefinitionToAddDeleteMethods && 930 (m->is_private() && (m->is_static() || m->is_final()))); 931 } 932 933 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions( 934 InstanceKlass* the_class, 935 InstanceKlass* scratch_class) { 936 int i; 937 938 // Check superclasses, or rather their names, since superclasses themselves can be 939 // requested to replace. 940 // Check for null superclass first since this might be java.lang.Object 941 if (the_class->super() != scratch_class->super() && 942 (the_class->super() == nullptr || scratch_class->super() == nullptr || 943 the_class->super()->name() != 944 scratch_class->super()->name())) { 945 log_info(redefine, class, normalize) 946 ("redefined class %s superclass change error: superclass changed from %s to %s.", 947 the_class->external_name(), 948 the_class->super() == nullptr ? "null" : the_class->super()->external_name(), 949 scratch_class->super() == nullptr ? "null" : scratch_class->super()->external_name()); 950 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 951 } 952 953 // Check if the number, names and order of directly implemented interfaces are the same. 954 // I think in principle we should just check if the sets of names of directly implemented 955 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the 956 // .java file, also changes in .class file) should not matter. However, comparing sets is 957 // technically a bit more difficult, and, more importantly, I am not sure at present that the 958 // order of interfaces does not matter on the implementation level, i.e. that the VM does not 959 // rely on it somewhere. 960 Array<InstanceKlass*>* k_interfaces = the_class->local_interfaces(); 961 Array<InstanceKlass*>* k_new_interfaces = scratch_class->local_interfaces(); 962 int n_intfs = k_interfaces->length(); 963 if (n_intfs != k_new_interfaces->length()) { 964 log_info(redefine, class, normalize) 965 ("redefined class %s interfaces change error: number of implemented interfaces changed from %d to %d.", 966 the_class->external_name(), n_intfs, k_new_interfaces->length()); 967 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 968 } 969 for (i = 0; i < n_intfs; i++) { 970 if (k_interfaces->at(i)->name() != 971 k_new_interfaces->at(i)->name()) { 972 log_info(redefine, class, normalize) 973 ("redefined class %s interfaces change error: interface changed from %s to %s.", 974 the_class->external_name(), 975 k_interfaces->at(i)->external_name(), k_new_interfaces->at(i)->external_name()); 976 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 977 } 978 } 979 980 // Check whether class is in the error init state. 981 if (the_class->is_in_error_state()) { 982 log_info(redefine, class, normalize) 983 ("redefined class %s is in error init state.", the_class->external_name()); 984 // TBD #5057930: special error code is needed in 1.6 985 return JVMTI_ERROR_INVALID_CLASS; 986 } 987 988 // Check whether the nest-related attributes have been changed. 989 jvmtiError err = check_nest_attributes(the_class, scratch_class); 990 if (err != JVMTI_ERROR_NONE) { 991 return err; 992 } 993 994 // Check whether the Record attribute has been changed. 995 err = check_record_attribute(the_class, scratch_class); 996 if (err != JVMTI_ERROR_NONE) { 997 return err; 998 } 999 1000 // Check whether the PermittedSubclasses attribute has been changed. 1001 err = check_permitted_subclasses_attribute(the_class, scratch_class); 1002 if (err != JVMTI_ERROR_NONE) { 1003 return err; 1004 } 1005 1006 // Check whether class modifiers are the same. 1007 u2 old_flags = the_class->access_flags().as_class_flags(); 1008 u2 new_flags = scratch_class->access_flags().as_class_flags(); 1009 if (old_flags != new_flags) { 1010 log_info(redefine, class, normalize) 1011 ("redefined class %s modifiers change error: modifiers changed from %d to %d.", 1012 the_class->external_name(), old_flags, new_flags); 1013 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED; 1014 } 1015 1016 // Check if the number, names, types and order of fields declared in these classes 1017 // are the same. 1018 JavaFieldStream old_fs(the_class); 1019 JavaFieldStream new_fs(scratch_class); 1020 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) { 1021 // name and signature 1022 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index()); 1023 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index()); 1024 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index()); 1025 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index()); 1026 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) { 1027 log_info(redefine, class, normalize) 1028 ("redefined class %s fields change error: field %s %s changed to %s %s.", 1029 the_class->external_name(), 1030 sig_sym1->as_C_string(), name_sym1->as_C_string(), 1031 sig_sym2->as_C_string(), name_sym2->as_C_string()); 1032 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 1033 } 1034 // offset 1035 if (old_fs.offset() != new_fs.offset()) { 1036 log_info(redefine, class, normalize) 1037 ("redefined class %s field %s change error: offset changed from %d to %d.", 1038 the_class->external_name(), name_sym2->as_C_string(), old_fs.offset(), new_fs.offset()); 1039 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 1040 } 1041 // access 1042 old_flags = old_fs.access_flags().as_field_flags(); 1043 new_flags = new_fs.access_flags().as_field_flags(); 1044 if (old_flags != new_flags) { 1045 log_info(redefine, class, normalize) 1046 ("redefined class %s field %s change error: modifiers changed from %d to %d.", 1047 the_class->external_name(), name_sym2->as_C_string(), old_flags, new_flags); 1048 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 1049 } 1050 } 1051 1052 // If both streams aren't done then we have a differing number of 1053 // fields. 1054 if (!old_fs.done() || !new_fs.done()) { 1055 const char* action = old_fs.done() ? "added" : "deleted"; 1056 log_info(redefine, class, normalize) 1057 ("redefined class %s fields change error: some fields were %s.", 1058 the_class->external_name(), action); 1059 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 1060 } 1061 1062 // Do a parallel walk through the old and new methods. Detect 1063 // cases where they match (exist in both), have been added in 1064 // the new methods, or have been deleted (exist only in the 1065 // old methods). The class file parser places methods in order 1066 // by method name, but does not order overloaded methods by 1067 // signature. In order to determine what fate befell the methods, 1068 // this code places the overloaded new methods that have matching 1069 // old methods in the same order as the old methods and places 1070 // new overloaded methods at the end of overloaded methods of 1071 // that name. The code for this order normalization is adapted 1072 // from the algorithm used in InstanceKlass::find_method(). 1073 // Since we are swapping out of order entries as we find them, 1074 // we only have to search forward through the overloaded methods. 1075 // Methods which are added and have the same name as an existing 1076 // method (but different signature) will be put at the end of 1077 // the methods with that name, and the name mismatch code will 1078 // handle them. 1079 Array<Method*>* k_old_methods(the_class->methods()); 1080 Array<Method*>* k_new_methods(scratch_class->methods()); 1081 int n_old_methods = k_old_methods->length(); 1082 int n_new_methods = k_new_methods->length(); 1083 Thread* thread = Thread::current(); 1084 1085 int ni = 0; 1086 int oi = 0; 1087 while (true) { 1088 Method* k_old_method; 1089 Method* k_new_method; 1090 enum { matched, added, deleted, undetermined } method_was = undetermined; 1091 1092 if (oi >= n_old_methods) { 1093 if (ni >= n_new_methods) { 1094 break; // we've looked at everything, done 1095 } 1096 // New method at the end 1097 k_new_method = k_new_methods->at(ni); 1098 method_was = added; 1099 } else if (ni >= n_new_methods) { 1100 // Old method, at the end, is deleted 1101 k_old_method = k_old_methods->at(oi); 1102 method_was = deleted; 1103 } else { 1104 // There are more methods in both the old and new lists 1105 k_old_method = k_old_methods->at(oi); 1106 k_new_method = k_new_methods->at(ni); 1107 if (k_old_method->name() != k_new_method->name()) { 1108 // Methods are sorted by method name, so a mismatch means added 1109 // or deleted 1110 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) { 1111 method_was = added; 1112 } else { 1113 method_was = deleted; 1114 } 1115 } else if (k_old_method->signature() == k_new_method->signature()) { 1116 // Both the name and signature match 1117 method_was = matched; 1118 } else { 1119 // The name matches, but the signature doesn't, which means we have to 1120 // search forward through the new overloaded methods. 1121 int nj; // outside the loop for post-loop check 1122 for (nj = ni + 1; nj < n_new_methods; nj++) { 1123 Method* m = k_new_methods->at(nj); 1124 if (k_old_method->name() != m->name()) { 1125 // reached another method name so no more overloaded methods 1126 method_was = deleted; 1127 break; 1128 } 1129 if (k_old_method->signature() == m->signature()) { 1130 // found a match so swap the methods 1131 k_new_methods->at_put(ni, m); 1132 k_new_methods->at_put(nj, k_new_method); 1133 k_new_method = m; 1134 method_was = matched; 1135 break; 1136 } 1137 } 1138 1139 if (nj >= n_new_methods) { 1140 // reached the end without a match; so method was deleted 1141 method_was = deleted; 1142 } 1143 } 1144 } 1145 1146 switch (method_was) { 1147 case matched: 1148 // methods match, be sure modifiers do too 1149 old_flags = k_old_method->access_flags().as_method_flags(); 1150 new_flags = k_new_method->access_flags().as_method_flags(); 1151 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) { 1152 log_info(redefine, class, normalize) 1153 ("redefined class %s method %s modifiers error: modifiers changed from %d to %d", 1154 the_class->external_name(), k_old_method->name_and_sig_as_C_string(), old_flags, new_flags); 1155 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED; 1156 } 1157 { 1158 u2 new_num = k_new_method->method_idnum(); 1159 u2 old_num = k_old_method->method_idnum(); 1160 if (new_num != old_num) { 1161 Method* idnum_owner = scratch_class->method_with_idnum(old_num); 1162 if (idnum_owner != nullptr) { 1163 // There is already a method assigned this idnum -- switch them 1164 // Take current and original idnum from the new_method 1165 idnum_owner->set_method_idnum(new_num); 1166 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum()); 1167 } 1168 // Take current and original idnum from the old_method 1169 k_new_method->set_method_idnum(old_num); 1170 k_new_method->set_orig_method_idnum(k_old_method->orig_method_idnum()); 1171 if (thread->has_pending_exception()) { 1172 return JVMTI_ERROR_OUT_OF_MEMORY; 1173 } 1174 } 1175 } 1176 JFR_ONLY(k_new_method->copy_trace_flags(k_old_method->trace_flags());) 1177 log_trace(redefine, class, normalize) 1178 ("Method matched: new: %s [%d] == old: %s [%d]", 1179 k_new_method->name_and_sig_as_C_string(), ni, k_old_method->name_and_sig_as_C_string(), oi); 1180 // advance to next pair of methods 1181 ++oi; 1182 ++ni; 1183 break; 1184 case added: 1185 // method added, see if it is OK 1186 if (!can_add_or_delete(k_new_method)) { 1187 log_info(redefine, class, normalize) 1188 ("redefined class %s methods error: added method: %s [%d]", 1189 the_class->external_name(), k_new_method->name_and_sig_as_C_string(), ni); 1190 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED; 1191 } 1192 { 1193 u2 num = the_class->next_method_idnum(); 1194 if (num == ConstMethod::UNSET_IDNUM) { 1195 // cannot add any more methods 1196 log_info(redefine, class, normalize) 1197 ("redefined class %s methods error: can't create ID for new method %s [%d]", 1198 the_class->external_name(), k_new_method->name_and_sig_as_C_string(), ni); 1199 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED; 1200 } 1201 u2 new_num = k_new_method->method_idnum(); 1202 Method* idnum_owner = scratch_class->method_with_idnum(num); 1203 if (idnum_owner != nullptr) { 1204 // There is already a method assigned this idnum -- switch them 1205 // Take current and original idnum from the new_method 1206 idnum_owner->set_method_idnum(new_num); 1207 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum()); 1208 } 1209 k_new_method->set_method_idnum(num); 1210 k_new_method->set_orig_method_idnum(num); 1211 if (thread->has_pending_exception()) { 1212 return JVMTI_ERROR_OUT_OF_MEMORY; 1213 } 1214 } 1215 log_trace(redefine, class, normalize) 1216 ("Method added: new: %s [%d]", k_new_method->name_and_sig_as_C_string(), ni); 1217 ++ni; // advance to next new method 1218 break; 1219 case deleted: 1220 // method deleted, see if it is OK 1221 if (!can_add_or_delete(k_old_method)) { 1222 log_info(redefine, class, normalize) 1223 ("redefined class %s methods error: deleted method %s [%d]", 1224 the_class->external_name(), k_old_method->name_and_sig_as_C_string(), oi); 1225 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED; 1226 } 1227 log_trace(redefine, class, normalize) 1228 ("Method deleted: old: %s [%d]", k_old_method->name_and_sig_as_C_string(), oi); 1229 ++oi; // advance to next old method 1230 break; 1231 default: 1232 ShouldNotReachHere(); 1233 } 1234 } 1235 1236 return JVMTI_ERROR_NONE; 1237 } 1238 1239 1240 // Find new constant pool index value for old constant pool index value 1241 // by searching the index map. Returns zero (0) if there is no mapped 1242 // value for the old constant pool index. 1243 u2 VM_RedefineClasses::find_new_index(int old_index) { 1244 if (_index_map_count == 0) { 1245 // map is empty so nothing can be found 1246 return 0; 1247 } 1248 1249 if (old_index < 1 || old_index >= _index_map_p->length()) { 1250 // The old_index is out of range so it is not mapped. This should 1251 // not happen in regular constant pool merging use, but it can 1252 // happen if a corrupt annotation is processed. 1253 return 0; 1254 } 1255 1256 int value = _index_map_p->at(old_index); 1257 if (value == -1) { 1258 // the old_index is not mapped 1259 return 0; 1260 } 1261 1262 // constant pool indices are u2, unless the merged constant pool overflows which 1263 // we don't check for. 1264 return checked_cast<u2>(value); 1265 } // end find_new_index() 1266 1267 1268 // Find new bootstrap specifier index value for old bootstrap specifier index 1269 // value by searching the index map. Returns unused index (-1) if there is 1270 // no mapped value for the old bootstrap specifier index. 1271 int VM_RedefineClasses::find_new_operand_index(int old_index) { 1272 if (_operands_index_map_count == 0) { 1273 // map is empty so nothing can be found 1274 return -1; 1275 } 1276 1277 if (old_index == -1 || old_index >= _operands_index_map_p->length()) { 1278 // The old_index is out of range so it is not mapped. 1279 // This should not happen in regular constant pool merging use. 1280 return -1; 1281 } 1282 1283 int value = _operands_index_map_p->at(old_index); 1284 if (value == -1) { 1285 // the old_index is not mapped 1286 return -1; 1287 } 1288 1289 return value; 1290 } // end find_new_operand_index() 1291 1292 1293 // The bug 6214132 caused the verification to fail. 1294 // 1. What's done in RedefineClasses() before verification: 1295 // a) A reference to the class being redefined (_the_class) and a 1296 // reference to new version of the class (_scratch_class) are 1297 // saved here for use during the bytecode verification phase of 1298 // RedefineClasses. 1299 // b) The _java_mirror field from _the_class is copied to the 1300 // _java_mirror field in _scratch_class. This means that a jclass 1301 // returned for _the_class or _scratch_class will refer to the 1302 // same Java mirror. The verifier will see the "one true mirror" 1303 // for the class being verified. 1304 // 2. See comments in JvmtiThreadState for what is done during verification. 1305 1306 class RedefineVerifyMark : public StackObj { 1307 private: 1308 JvmtiThreadState* _state; 1309 Klass* _scratch_class; 1310 OopHandle _scratch_mirror; 1311 1312 public: 1313 1314 RedefineVerifyMark(Klass* the_class, Klass* scratch_class, 1315 JvmtiThreadState* state) : _state(state), _scratch_class(scratch_class) 1316 { 1317 _state->set_class_versions_map(the_class, scratch_class); 1318 _scratch_mirror = the_class->java_mirror_handle(); // this is a copy that is swapped 1319 _scratch_class->swap_java_mirror_handle(_scratch_mirror); 1320 } 1321 1322 ~RedefineVerifyMark() { 1323 // Restore the scratch class's mirror, so when scratch_class is removed 1324 // the correct mirror pointing to it can be cleared. 1325 _scratch_class->swap_java_mirror_handle(_scratch_mirror); 1326 _state->clear_class_versions_map(); 1327 } 1328 }; 1329 1330 1331 jvmtiError VM_RedefineClasses::load_new_class_versions() { 1332 1333 // For consistency allocate memory using os::malloc wrapper. 1334 _scratch_classes = (InstanceKlass**) 1335 os::malloc(sizeof(InstanceKlass*) * _class_count, mtClass); 1336 if (_scratch_classes == nullptr) { 1337 return JVMTI_ERROR_OUT_OF_MEMORY; 1338 } 1339 // Zero initialize the _scratch_classes array. 1340 for (int i = 0; i < _class_count; i++) { 1341 _scratch_classes[i] = nullptr; 1342 } 1343 1344 JavaThread* current = JavaThread::current(); 1345 ResourceMark rm(current); 1346 1347 JvmtiThreadState *state = JvmtiThreadState::state_for(current); 1348 // state can only be null if the current thread is exiting which 1349 // should not happen since we're trying to do a RedefineClasses 1350 guarantee(state != nullptr, "exiting thread calling load_new_class_versions"); 1351 for (int i = 0; i < _class_count; i++) { 1352 // Create HandleMark so that any handles created while loading new class 1353 // versions are deleted. Constant pools are deallocated while merging 1354 // constant pools 1355 HandleMark hm(current); 1356 InstanceKlass* the_class = get_ik(_class_defs[i].klass); 1357 1358 log_debug(redefine, class, load) 1359 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)", 1360 the_class->external_name(), _class_load_kind, os::available_memory() >> 10); 1361 1362 ClassFileStream st((u1*)_class_defs[i].class_bytes, 1363 _class_defs[i].class_byte_count, 1364 "__VM_RedefineClasses__"); 1365 1366 // Set redefined class handle in JvmtiThreadState class. 1367 // This redefined class is sent to agent event handler for class file 1368 // load hook event. 1369 state->set_class_being_redefined(the_class, _class_load_kind); 1370 1371 JavaThread* THREAD = current; // For exception macros. 1372 ExceptionMark em(THREAD); 1373 Handle protection_domain(THREAD, the_class->protection_domain()); 1374 ClassLoadInfo cl_info(protection_domain); 1375 // Parse and create a class from the bytes, but this class isn't added 1376 // to the dictionary, so do not call resolve_from_stream. 1377 InstanceKlass* scratch_class = KlassFactory::create_from_stream(&st, 1378 the_class->name(), 1379 the_class->class_loader_data(), 1380 cl_info, 1381 THREAD); 1382 1383 // Clear class_being_redefined just to be sure. 1384 state->clear_class_being_redefined(); 1385 1386 // TODO: if this is retransform, and nothing changed we can skip it 1387 1388 // Need to clean up allocated InstanceKlass if there's an error so assign 1389 // the result here. Caller deallocates all the scratch classes in case of 1390 // an error. 1391 _scratch_classes[i] = scratch_class; 1392 1393 if (HAS_PENDING_EXCEPTION) { 1394 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1395 log_info(redefine, class, load, exceptions)("create_from_stream exception: '%s'", ex_name->as_C_string()); 1396 CLEAR_PENDING_EXCEPTION; 1397 1398 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) { 1399 return JVMTI_ERROR_UNSUPPORTED_VERSION; 1400 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) { 1401 return JVMTI_ERROR_INVALID_CLASS_FORMAT; 1402 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) { 1403 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION; 1404 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) { 1405 // The message will be "XXX (wrong name: YYY)" 1406 return JVMTI_ERROR_NAMES_DONT_MATCH; 1407 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1408 return JVMTI_ERROR_OUT_OF_MEMORY; 1409 } else { // Just in case more exceptions can be thrown.. 1410 return JVMTI_ERROR_FAILS_VERIFICATION; 1411 } 1412 } 1413 1414 // Ensure class is linked before redefine 1415 if (!the_class->is_linked()) { 1416 the_class->link_class(THREAD); 1417 if (HAS_PENDING_EXCEPTION) { 1418 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1419 oop message = java_lang_Throwable::message(PENDING_EXCEPTION); 1420 if (message != nullptr) { 1421 char* ex_msg = java_lang_String::as_utf8_string(message); 1422 log_info(redefine, class, load, exceptions)("link_class exception: '%s %s'", 1423 ex_name->as_C_string(), ex_msg); 1424 } else { 1425 log_info(redefine, class, load, exceptions)("link_class exception: '%s'", 1426 ex_name->as_C_string()); 1427 } 1428 CLEAR_PENDING_EXCEPTION; 1429 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1430 return JVMTI_ERROR_OUT_OF_MEMORY; 1431 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) { 1432 return JVMTI_ERROR_INVALID_CLASS; 1433 } else { 1434 return JVMTI_ERROR_INTERNAL; 1435 } 1436 } 1437 } 1438 1439 // Do the validity checks in compare_and_normalize_class_versions() 1440 // before verifying the byte codes. By doing these checks first, we 1441 // limit the number of functions that require redirection from 1442 // the_class to scratch_class. In particular, we don't have to 1443 // modify JNI GetSuperclass() and thus won't change its performance. 1444 jvmtiError res = compare_and_normalize_class_versions(the_class, 1445 scratch_class); 1446 if (res != JVMTI_ERROR_NONE) { 1447 return res; 1448 } 1449 1450 // verify what the caller passed us 1451 { 1452 // The bug 6214132 caused the verification to fail. 1453 // Information about the_class and scratch_class is temporarily 1454 // recorded into jvmtiThreadState. This data is used to redirect 1455 // the_class to scratch_class in the JVM_* functions called by the 1456 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed 1457 // description. 1458 RedefineVerifyMark rvm(the_class, scratch_class, state); 1459 Verifier::verify(scratch_class, true, THREAD); 1460 } 1461 1462 if (HAS_PENDING_EXCEPTION) { 1463 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1464 log_info(redefine, class, load, exceptions)("verify_byte_codes exception: '%s'", ex_name->as_C_string()); 1465 CLEAR_PENDING_EXCEPTION; 1466 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1467 return JVMTI_ERROR_OUT_OF_MEMORY; 1468 } else { 1469 // tell the caller the bytecodes are bad 1470 return JVMTI_ERROR_FAILS_VERIFICATION; 1471 } 1472 } 1473 1474 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD); 1475 if (HAS_PENDING_EXCEPTION) { 1476 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1477 log_info(redefine, class, load, exceptions)("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string()); 1478 CLEAR_PENDING_EXCEPTION; 1479 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1480 return JVMTI_ERROR_OUT_OF_MEMORY; 1481 } else { 1482 return JVMTI_ERROR_INTERNAL; 1483 } 1484 } 1485 1486 #ifdef ASSERT 1487 { 1488 // verify what we have done during constant pool merging 1489 { 1490 RedefineVerifyMark rvm(the_class, scratch_class, state); 1491 Verifier::verify(scratch_class, true, THREAD); 1492 } 1493 1494 if (HAS_PENDING_EXCEPTION) { 1495 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1496 log_info(redefine, class, load, exceptions) 1497 ("verify_byte_codes post merge-CP exception: '%s'", ex_name->as_C_string()); 1498 CLEAR_PENDING_EXCEPTION; 1499 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1500 return JVMTI_ERROR_OUT_OF_MEMORY; 1501 } else { 1502 // tell the caller that constant pool merging screwed up 1503 return JVMTI_ERROR_INTERNAL; 1504 } 1505 } 1506 } 1507 #endif // ASSERT 1508 1509 Rewriter::rewrite(scratch_class, THREAD); 1510 if (!HAS_PENDING_EXCEPTION) { 1511 scratch_class->link_methods(THREAD); 1512 } 1513 if (HAS_PENDING_EXCEPTION) { 1514 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1515 log_info(redefine, class, load, exceptions) 1516 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string()); 1517 CLEAR_PENDING_EXCEPTION; 1518 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1519 return JVMTI_ERROR_OUT_OF_MEMORY; 1520 } else { 1521 return JVMTI_ERROR_INTERNAL; 1522 } 1523 } 1524 1525 log_debug(redefine, class, load) 1526 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)", the_class->external_name(), os::available_memory() >> 10); 1527 } 1528 1529 return JVMTI_ERROR_NONE; 1530 } 1531 1532 1533 // Map old_index to new_index as needed. scratch_cp is only needed 1534 // for log calls. 1535 void VM_RedefineClasses::map_index(const constantPoolHandle& scratch_cp, 1536 int old_index, int new_index) { 1537 if (find_new_index(old_index) != 0) { 1538 // old_index is already mapped 1539 return; 1540 } 1541 1542 if (old_index == new_index) { 1543 // no mapping is needed 1544 return; 1545 } 1546 1547 _index_map_p->at_put(old_index, new_index); 1548 _index_map_count++; 1549 1550 log_trace(redefine, class, constantpool) 1551 ("mapped tag %d at index %d to %d", scratch_cp->tag_at(old_index).value(), old_index, new_index); 1552 } // end map_index() 1553 1554 1555 // Map old_index to new_index as needed. 1556 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) { 1557 if (find_new_operand_index(old_index) != -1) { 1558 // old_index is already mapped 1559 return; 1560 } 1561 1562 if (old_index == new_index) { 1563 // no mapping is needed 1564 return; 1565 } 1566 1567 _operands_index_map_p->at_put(old_index, new_index); 1568 _operands_index_map_count++; 1569 1570 log_trace(redefine, class, constantpool)("mapped bootstrap specifier at index %d to %d", old_index, new_index); 1571 } // end map_index() 1572 1573 1574 // Merge old_cp and scratch_cp and return the results of the merge via 1575 // merge_cp_p. The number of entries in *merge_cp_p is returned via 1576 // merge_cp_length_p. The entries in old_cp occupy the same locations 1577 // in *merge_cp_p. Also creates a map of indices from entries in 1578 // scratch_cp to the corresponding entry in *merge_cp_p. Index map 1579 // entries are only created for entries in scratch_cp that occupy a 1580 // different location in *merged_cp_p. 1581 bool VM_RedefineClasses::merge_constant_pools(const constantPoolHandle& old_cp, 1582 const constantPoolHandle& scratch_cp, constantPoolHandle *merge_cp_p, 1583 int *merge_cp_length_p, TRAPS) { 1584 1585 if (merge_cp_p == nullptr) { 1586 assert(false, "caller must provide scratch constantPool"); 1587 return false; // robustness 1588 } 1589 if (merge_cp_length_p == nullptr) { 1590 assert(false, "caller must provide scratch CP length"); 1591 return false; // robustness 1592 } 1593 // Worst case we need old_cp->length() + scratch_cp()->length(), 1594 // but the caller might be smart so make sure we have at least 1595 // the minimum. 1596 if ((*merge_cp_p)->length() < old_cp->length()) { 1597 assert(false, "merge area too small"); 1598 return false; // robustness 1599 } 1600 1601 log_info(redefine, class, constantpool)("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(), scratch_cp->length()); 1602 1603 { 1604 // Pass 0: 1605 // The old_cp is copied to *merge_cp_p; this means that any code 1606 // using old_cp does not have to change. This work looks like a 1607 // perfect fit for ConstantPool*::copy_cp_to(), but we need to 1608 // handle one special case: 1609 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass 1610 // This will make verification happy. 1611 1612 int old_i; // index into old_cp 1613 1614 // index zero (0) is not used in constantPools 1615 for (old_i = 1; old_i < old_cp->length(); old_i++) { 1616 // leave debugging crumb 1617 jbyte old_tag = old_cp->tag_at(old_i).value(); 1618 switch (old_tag) { 1619 case JVM_CONSTANT_Class: 1620 case JVM_CONSTANT_UnresolvedClass: 1621 // revert the copy to JVM_CONSTANT_UnresolvedClass 1622 // May be resolving while calling this so do the same for 1623 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition) 1624 (*merge_cp_p)->temp_unresolved_klass_at_put(old_i, 1625 old_cp->klass_name_index_at(old_i)); 1626 break; 1627 1628 case JVM_CONSTANT_Double: 1629 case JVM_CONSTANT_Long: 1630 // just copy the entry to *merge_cp_p, but double and long take 1631 // two constant pool entries 1632 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i); 1633 old_i++; 1634 break; 1635 1636 default: 1637 // just copy the entry to *merge_cp_p 1638 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i); 1639 break; 1640 } 1641 } // end for each old_cp entry 1642 1643 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_false); 1644 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_false); 1645 1646 // We don't need to sanity check that *merge_cp_length_p is within 1647 // *merge_cp_p bounds since we have the minimum on-entry check above. 1648 (*merge_cp_length_p) = old_i; 1649 } 1650 1651 // merge_cp_len should be the same as old_cp->length() at this point 1652 // so this trace message is really a "warm-and-breathing" message. 1653 log_debug(redefine, class, constantpool)("after pass 0: merge_cp_len=%d", *merge_cp_length_p); 1654 1655 int scratch_i; // index into scratch_cp 1656 { 1657 // Pass 1a: 1658 // Compare scratch_cp entries to the old_cp entries that we have 1659 // already copied to *merge_cp_p. In this pass, we are eliminating 1660 // exact duplicates (matching entry at same index) so we only 1661 // compare entries in the common indice range. 1662 int increment = 1; 1663 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length()); 1664 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) { 1665 switch (scratch_cp->tag_at(scratch_i).value()) { 1666 case JVM_CONSTANT_Double: 1667 case JVM_CONSTANT_Long: 1668 // double and long take two constant pool entries 1669 increment = 2; 1670 break; 1671 1672 default: 1673 increment = 1; 1674 break; 1675 } 1676 1677 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p, scratch_i); 1678 if (match) { 1679 // found a match at the same index so nothing more to do 1680 continue; 1681 } 1682 1683 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p); 1684 if (found_i != 0) { 1685 guarantee(found_i != scratch_i, 1686 "compare_entry_to() and find_matching_entry() do not agree"); 1687 1688 // Found a matching entry somewhere else in *merge_cp_p so 1689 // just need a mapping entry. 1690 map_index(scratch_cp, scratch_i, found_i); 1691 continue; 1692 } 1693 1694 // No match found so we have to append this entry and any unique 1695 // referenced entries to *merge_cp_p. 1696 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p); 1697 } 1698 } 1699 1700 log_debug(redefine, class, constantpool) 1701 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", 1702 *merge_cp_length_p, scratch_i, _index_map_count); 1703 1704 if (scratch_i < scratch_cp->length()) { 1705 // Pass 1b: 1706 // old_cp is smaller than scratch_cp so there are entries in 1707 // scratch_cp that we have not yet processed. We take care of 1708 // those now. 1709 int increment = 1; 1710 for (; scratch_i < scratch_cp->length(); scratch_i += increment) { 1711 switch (scratch_cp->tag_at(scratch_i).value()) { 1712 case JVM_CONSTANT_Double: 1713 case JVM_CONSTANT_Long: 1714 // double and long take two constant pool entries 1715 increment = 2; 1716 break; 1717 1718 default: 1719 increment = 1; 1720 break; 1721 } 1722 1723 int found_i = 1724 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p); 1725 if (found_i != 0) { 1726 // Found a matching entry somewhere else in *merge_cp_p so 1727 // just need a mapping entry. 1728 map_index(scratch_cp, scratch_i, found_i); 1729 continue; 1730 } 1731 1732 // No match found so we have to append this entry and any unique 1733 // referenced entries to *merge_cp_p. 1734 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p); 1735 } 1736 1737 log_debug(redefine, class, constantpool) 1738 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", 1739 *merge_cp_length_p, scratch_i, _index_map_count); 1740 } 1741 finalize_operands_merge(*merge_cp_p, CHECK_false); 1742 1743 return true; 1744 } // end merge_constant_pools() 1745 1746 1747 // Scoped object to clean up the constant pool(s) created for merging 1748 class MergeCPCleaner { 1749 ClassLoaderData* _loader_data; 1750 ConstantPool* _cp; 1751 ConstantPool* _scratch_cp; 1752 public: 1753 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) : 1754 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(nullptr) {} 1755 ~MergeCPCleaner() { 1756 _loader_data->add_to_deallocate_list(_cp); 1757 if (_scratch_cp != nullptr) { 1758 _loader_data->add_to_deallocate_list(_scratch_cp); 1759 } 1760 } 1761 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; } 1762 }; 1763 1764 // Merge constant pools between the_class and scratch_class and 1765 // potentially rewrite bytecodes in scratch_class to use the merged 1766 // constant pool. 1767 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite( 1768 InstanceKlass* the_class, InstanceKlass* scratch_class, 1769 TRAPS) { 1770 // worst case merged constant pool length is old and new combined 1771 int merge_cp_length = the_class->constants()->length() 1772 + scratch_class->constants()->length(); 1773 1774 // Constant pools are not easily reused so we allocate a new one 1775 // each time. 1776 // merge_cp is created unsafe for concurrent GC processing. It 1777 // should be marked safe before discarding it. Even though 1778 // garbage, if it crosses a card boundary, it may be scanned 1779 // in order to find the start of the first complete object on the card. 1780 ClassLoaderData* loader_data = the_class->class_loader_data(); 1781 ConstantPool* merge_cp_oop = 1782 ConstantPool::allocate(loader_data, 1783 merge_cp_length, 1784 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1785 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop); 1786 1787 HandleMark hm(THREAD); // make sure handles are cleared before 1788 // MergeCPCleaner clears out merge_cp_oop 1789 constantPoolHandle merge_cp(THREAD, merge_cp_oop); 1790 1791 // Get constants() from the old class because it could have been rewritten 1792 // while we were at a safepoint allocating a new constant pool. 1793 constantPoolHandle old_cp(THREAD, the_class->constants()); 1794 constantPoolHandle scratch_cp(THREAD, scratch_class->constants()); 1795 1796 // If the length changed, the class was redefined out from under us. Return 1797 // an error. 1798 if (merge_cp_length != the_class->constants()->length() 1799 + scratch_class->constants()->length()) { 1800 return JVMTI_ERROR_INTERNAL; 1801 } 1802 1803 // Update the version number of the constant pools (may keep scratch_cp) 1804 merge_cp->increment_and_save_version(old_cp->version()); 1805 scratch_cp->increment_and_save_version(old_cp->version()); 1806 1807 ResourceMark rm(THREAD); 1808 _index_map_count = 0; 1809 _index_map_p = new intArray(scratch_cp->length(), scratch_cp->length(), -1); 1810 1811 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands()); 1812 _operands_index_map_count = 0; 1813 int operands_index_map_len = ConstantPool::operand_array_length(scratch_cp->operands()); 1814 _operands_index_map_p = new intArray(operands_index_map_len, operands_index_map_len, -1); 1815 1816 // reference to the cp holder is needed for copy_operands() 1817 merge_cp->set_pool_holder(scratch_class); 1818 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp, 1819 &merge_cp_length, THREAD); 1820 merge_cp->set_pool_holder(nullptr); 1821 1822 if (!result) { 1823 // The merge can fail due to memory allocation failure or due 1824 // to robustness checks. 1825 return JVMTI_ERROR_INTERNAL; 1826 } 1827 1828 // ensure merged constant pool size does not overflow u2 1829 if (merge_cp_length > 0xFFFF) { 1830 log_warning(redefine, class, constantpool)("Merged constant pool overflow: %d entries", merge_cp_length); 1831 return JVMTI_ERROR_INTERNAL; 1832 } 1833 1834 // Set dynamic constants attribute from the original CP. 1835 if (old_cp->has_dynamic_constant()) { 1836 scratch_cp->set_has_dynamic_constant(); 1837 } 1838 1839 log_info(redefine, class, constantpool)("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count); 1840 1841 if (_index_map_count == 0) { 1842 // there is nothing to map between the new and merged constant pools 1843 1844 // Copy attributes from scratch_cp to merge_cp 1845 merge_cp->copy_fields(scratch_cp()); 1846 1847 if (old_cp->length() == scratch_cp->length()) { 1848 // The old and new constant pools are the same length and the 1849 // index map is empty. This means that the three constant pools 1850 // are equivalent (but not the same). Unfortunately, the new 1851 // constant pool has not gone through link resolution nor have 1852 // the new class bytecodes gone through constant pool cache 1853 // rewriting so we can't use the old constant pool with the new 1854 // class. 1855 1856 // toss the merged constant pool at return 1857 } else if (old_cp->length() < scratch_cp->length()) { 1858 // The old constant pool has fewer entries than the new constant 1859 // pool and the index map is empty. This means the new constant 1860 // pool is a superset of the old constant pool. However, the old 1861 // class bytecodes have already gone through constant pool cache 1862 // rewriting so we can't use the new constant pool with the old 1863 // class. 1864 1865 // toss the merged constant pool at return 1866 } else { 1867 // The old constant pool has more entries than the new constant 1868 // pool and the index map is empty. This means that both the old 1869 // and merged constant pools are supersets of the new constant 1870 // pool. 1871 1872 // Replace the new constant pool with a shrunken copy of the 1873 // merged constant pool 1874 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, 1875 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1876 // The new constant pool replaces scratch_cp so have cleaner clean it up. 1877 // It can't be cleaned up while there are handles to it. 1878 cp_cleaner.add_scratch_cp(scratch_cp()); 1879 } 1880 } else { 1881 if (log_is_enabled(Trace, redefine, class, constantpool)) { 1882 // don't want to loop unless we are tracing 1883 int count = 0; 1884 for (int i = 1; i < _index_map_p->length(); i++) { 1885 int value = _index_map_p->at(i); 1886 1887 if (value != -1) { 1888 log_trace(redefine, class, constantpool)("index_map[%d]: old=%d new=%d", count, i, value); 1889 count++; 1890 } 1891 } 1892 } 1893 1894 // We have entries mapped between the new and merged constant pools 1895 // so we have to rewrite some constant pool references. 1896 if (!rewrite_cp_refs(scratch_class)) { 1897 return JVMTI_ERROR_INTERNAL; 1898 } 1899 1900 // Copy attributes from scratch_cp to merge_cp (should be done after rewrite_cp_refs()) 1901 merge_cp->copy_fields(scratch_cp()); 1902 1903 // Replace the new constant pool with a shrunken copy of the 1904 // merged constant pool so now the rewritten bytecodes have 1905 // valid references; the previous new constant pool will get 1906 // GCed. 1907 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, 1908 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1909 // The new constant pool replaces scratch_cp so have cleaner clean it up. 1910 // It can't be cleaned up while there are handles to it. 1911 cp_cleaner.add_scratch_cp(scratch_cp()); 1912 } 1913 1914 return JVMTI_ERROR_NONE; 1915 } // end merge_cp_and_rewrite() 1916 1917 1918 // Rewrite constant pool references in klass scratch_class. 1919 bool VM_RedefineClasses::rewrite_cp_refs(InstanceKlass* scratch_class) { 1920 1921 // rewrite constant pool references in the nest attributes: 1922 if (!rewrite_cp_refs_in_nest_attributes(scratch_class)) { 1923 // propagate failure back to caller 1924 return false; 1925 } 1926 1927 // rewrite constant pool references in the Record attribute: 1928 if (!rewrite_cp_refs_in_record_attribute(scratch_class)) { 1929 // propagate failure back to caller 1930 return false; 1931 } 1932 1933 // rewrite constant pool references in the PermittedSubclasses attribute: 1934 if (!rewrite_cp_refs_in_permitted_subclasses_attribute(scratch_class)) { 1935 // propagate failure back to caller 1936 return false; 1937 } 1938 1939 // rewrite constant pool references in the methods: 1940 if (!rewrite_cp_refs_in_methods(scratch_class)) { 1941 // propagate failure back to caller 1942 return false; 1943 } 1944 1945 // rewrite constant pool references in the class_annotations: 1946 if (!rewrite_cp_refs_in_class_annotations(scratch_class)) { 1947 // propagate failure back to caller 1948 return false; 1949 } 1950 1951 // rewrite constant pool references in the fields_annotations: 1952 if (!rewrite_cp_refs_in_fields_annotations(scratch_class)) { 1953 // propagate failure back to caller 1954 return false; 1955 } 1956 1957 // rewrite constant pool references in the methods_annotations: 1958 if (!rewrite_cp_refs_in_methods_annotations(scratch_class)) { 1959 // propagate failure back to caller 1960 return false; 1961 } 1962 1963 // rewrite constant pool references in the methods_parameter_annotations: 1964 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class)) { 1965 // propagate failure back to caller 1966 return false; 1967 } 1968 1969 // rewrite constant pool references in the methods_default_annotations: 1970 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class)) { 1971 // propagate failure back to caller 1972 return false; 1973 } 1974 1975 // rewrite constant pool references in the class_type_annotations: 1976 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class)) { 1977 // propagate failure back to caller 1978 return false; 1979 } 1980 1981 // rewrite constant pool references in the fields_type_annotations: 1982 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class)) { 1983 // propagate failure back to caller 1984 return false; 1985 } 1986 1987 // rewrite constant pool references in the methods_type_annotations: 1988 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class)) { 1989 // propagate failure back to caller 1990 return false; 1991 } 1992 1993 // There can be type annotations in the Code part of a method_info attribute. 1994 // These annotations are not accessible, even by reflection. 1995 // Currently they are not even parsed by the ClassFileParser. 1996 // If runtime access is added they will also need to be rewritten. 1997 1998 // rewrite source file name index: 1999 u2 source_file_name_idx = scratch_class->source_file_name_index(); 2000 if (source_file_name_idx != 0) { 2001 u2 new_source_file_name_idx = find_new_index(source_file_name_idx); 2002 if (new_source_file_name_idx != 0) { 2003 scratch_class->set_source_file_name_index(new_source_file_name_idx); 2004 } 2005 } 2006 2007 // rewrite class generic signature index: 2008 u2 generic_signature_index = scratch_class->generic_signature_index(); 2009 if (generic_signature_index != 0) { 2010 u2 new_generic_signature_index = find_new_index(generic_signature_index); 2011 if (new_generic_signature_index != 0) { 2012 scratch_class->set_generic_signature_index(new_generic_signature_index); 2013 } 2014 } 2015 2016 return true; 2017 } // end rewrite_cp_refs() 2018 2019 // Rewrite constant pool references in the NestHost and NestMembers attributes. 2020 bool VM_RedefineClasses::rewrite_cp_refs_in_nest_attributes( 2021 InstanceKlass* scratch_class) { 2022 2023 u2 cp_index = scratch_class->nest_host_index(); 2024 if (cp_index != 0) { 2025 scratch_class->set_nest_host_index(find_new_index(cp_index)); 2026 } 2027 Array<u2>* nest_members = scratch_class->nest_members(); 2028 for (int i = 0; i < nest_members->length(); i++) { 2029 u2 cp_index = nest_members->at(i); 2030 nest_members->at_put(i, find_new_index(cp_index)); 2031 } 2032 return true; 2033 } 2034 2035 // Rewrite constant pool references in the Record attribute. 2036 bool VM_RedefineClasses::rewrite_cp_refs_in_record_attribute(InstanceKlass* scratch_class) { 2037 Array<RecordComponent*>* components = scratch_class->record_components(); 2038 if (components != nullptr) { 2039 for (int i = 0; i < components->length(); i++) { 2040 RecordComponent* component = components->at(i); 2041 u2 cp_index = component->name_index(); 2042 component->set_name_index(find_new_index(cp_index)); 2043 cp_index = component->descriptor_index(); 2044 component->set_descriptor_index(find_new_index(cp_index)); 2045 cp_index = component->generic_signature_index(); 2046 if (cp_index != 0) { 2047 component->set_generic_signature_index(find_new_index(cp_index)); 2048 } 2049 2050 AnnotationArray* annotations = component->annotations(); 2051 if (annotations != nullptr && annotations->length() != 0) { 2052 int byte_i = 0; // byte index into annotations 2053 if (!rewrite_cp_refs_in_annotations_typeArray(annotations, byte_i)) { 2054 log_debug(redefine, class, annotation)("bad record_component_annotations at %d", i); 2055 // propagate failure back to caller 2056 return false; 2057 } 2058 } 2059 2060 AnnotationArray* type_annotations = component->type_annotations(); 2061 if (type_annotations != nullptr && type_annotations->length() != 0) { 2062 int byte_i = 0; // byte index into annotations 2063 if (!rewrite_cp_refs_in_annotations_typeArray(type_annotations, byte_i)) { 2064 log_debug(redefine, class, annotation)("bad record_component_type_annotations at %d", i); 2065 // propagate failure back to caller 2066 return false; 2067 } 2068 } 2069 } 2070 } 2071 return true; 2072 } 2073 2074 // Rewrite constant pool references in the PermittedSubclasses attribute. 2075 bool VM_RedefineClasses::rewrite_cp_refs_in_permitted_subclasses_attribute( 2076 InstanceKlass* scratch_class) { 2077 2078 Array<u2>* permitted_subclasses = scratch_class->permitted_subclasses(); 2079 assert(permitted_subclasses != nullptr, "unexpected null permitted_subclasses"); 2080 for (int i = 0; i < permitted_subclasses->length(); i++) { 2081 u2 cp_index = permitted_subclasses->at(i); 2082 permitted_subclasses->at_put(i, find_new_index(cp_index)); 2083 } 2084 return true; 2085 } 2086 2087 // Rewrite constant pool references in the methods. 2088 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(InstanceKlass* scratch_class) { 2089 2090 Array<Method*>* methods = scratch_class->methods(); 2091 2092 if (methods == nullptr || methods->length() == 0) { 2093 // no methods so nothing to do 2094 return true; 2095 } 2096 2097 JavaThread* THREAD = JavaThread::current(); // For exception macros. 2098 ExceptionMark em(THREAD); 2099 2100 // rewrite constant pool references in the methods: 2101 for (int i = methods->length() - 1; i >= 0; i--) { 2102 methodHandle method(THREAD, methods->at(i)); 2103 methodHandle new_method; 2104 rewrite_cp_refs_in_method(method, &new_method, THREAD); 2105 if (!new_method.is_null()) { 2106 // the method has been replaced so save the new method version 2107 // even in the case of an exception. original method is on the 2108 // deallocation list. 2109 methods->at_put(i, new_method()); 2110 } 2111 if (HAS_PENDING_EXCEPTION) { 2112 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 2113 log_info(redefine, class, load, exceptions)("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string()); 2114 // Need to clear pending exception here as the super caller sets 2115 // the JVMTI_ERROR_INTERNAL if the returned value is false. 2116 CLEAR_PENDING_EXCEPTION; 2117 return false; 2118 } 2119 } 2120 2121 return true; 2122 } 2123 2124 2125 // Rewrite constant pool references in the specific method. This code 2126 // was adapted from Rewriter::rewrite_method(). 2127 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method, 2128 methodHandle *new_method_p, TRAPS) { 2129 2130 *new_method_p = methodHandle(); // default is no new method 2131 2132 // We cache a pointer to the bytecodes here in code_base. If GC 2133 // moves the Method*, then the bytecodes will also move which 2134 // will likely cause a crash. We create a NoSafepointVerifier 2135 // object to detect whether we pass a possible safepoint in this 2136 // code block. 2137 NoSafepointVerifier nsv; 2138 2139 // Bytecodes and their length 2140 address code_base = method->code_base(); 2141 int code_length = method->code_size(); 2142 2143 int bc_length; 2144 for (int bci = 0; bci < code_length; bci += bc_length) { 2145 address bcp = code_base + bci; 2146 Bytecodes::Code c = (Bytecodes::Code)(*bcp); 2147 2148 bc_length = Bytecodes::length_for(c); 2149 if (bc_length == 0) { 2150 // More complicated bytecodes report a length of zero so 2151 // we have to try again a slightly different way. 2152 bc_length = Bytecodes::length_at(method(), bcp); 2153 } 2154 2155 assert(bc_length != 0, "impossible bytecode length"); 2156 2157 switch (c) { 2158 case Bytecodes::_ldc: 2159 { 2160 u1 cp_index = *(bcp + 1); 2161 u2 new_index = find_new_index(cp_index); 2162 2163 if (StressLdcRewrite && new_index == 0) { 2164 // If we are stressing ldc -> ldc_w rewriting, then we 2165 // always need a new_index value. 2166 new_index = cp_index; 2167 } 2168 if (new_index != 0) { 2169 // the original index is mapped so we have more work to do 2170 if (!StressLdcRewrite && new_index <= max_jubyte) { 2171 // The new value can still use ldc instead of ldc_w 2172 // unless we are trying to stress ldc -> ldc_w rewriting 2173 log_trace(redefine, class, constantpool) 2174 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index); 2175 // We checked that new_index fits in a u1 so this cast is safe 2176 *(bcp + 1) = (u1)new_index; 2177 } else { 2178 log_trace(redefine, class, constantpool) 2179 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index); 2180 // the new value needs ldc_w instead of ldc 2181 u_char inst_buffer[4]; // max instruction size is 4 bytes 2182 bcp = (address)inst_buffer; 2183 // construct new instruction sequence 2184 *bcp = Bytecodes::_ldc_w; 2185 bcp++; 2186 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w. 2187 // See comment below for difference between put_Java_u2() 2188 // and put_native_u2(). 2189 Bytes::put_Java_u2(bcp, new_index); 2190 2191 Relocator rc(method, nullptr /* no RelocatorListener needed */); 2192 methodHandle m; 2193 { 2194 PauseNoSafepointVerifier pnsv(&nsv); 2195 2196 // ldc is 2 bytes and ldc_w is 3 bytes 2197 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK); 2198 } 2199 2200 // return the new method so that the caller can update 2201 // the containing class 2202 *new_method_p = method = m; 2203 // switch our bytecode processing loop from the old method 2204 // to the new method 2205 code_base = method->code_base(); 2206 code_length = method->code_size(); 2207 bcp = code_base + bci; 2208 c = (Bytecodes::Code)(*bcp); 2209 bc_length = Bytecodes::length_for(c); 2210 assert(bc_length != 0, "sanity check"); 2211 } // end we need ldc_w instead of ldc 2212 } // end if there is a mapped index 2213 } break; 2214 2215 // these bytecodes have a two-byte constant pool index 2216 case Bytecodes::_anewarray : // fall through 2217 case Bytecodes::_checkcast : // fall through 2218 case Bytecodes::_getfield : // fall through 2219 case Bytecodes::_getstatic : // fall through 2220 case Bytecodes::_instanceof : // fall through 2221 case Bytecodes::_invokedynamic : // fall through 2222 case Bytecodes::_invokeinterface: // fall through 2223 case Bytecodes::_invokespecial : // fall through 2224 case Bytecodes::_invokestatic : // fall through 2225 case Bytecodes::_invokevirtual : // fall through 2226 case Bytecodes::_ldc_w : // fall through 2227 case Bytecodes::_ldc2_w : // fall through 2228 case Bytecodes::_multianewarray : // fall through 2229 case Bytecodes::_new : // fall through 2230 case Bytecodes::_putfield : // fall through 2231 case Bytecodes::_putstatic : 2232 { 2233 address p = bcp + 1; 2234 int cp_index = Bytes::get_Java_u2(p); 2235 u2 new_index = find_new_index(cp_index); 2236 if (new_index != 0) { 2237 // the original index is mapped so update w/ new value 2238 log_trace(redefine, class, constantpool) 2239 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),p2i(bcp), cp_index, new_index); 2240 // Rewriter::rewrite_method() uses put_native_u2() in this 2241 // situation because it is reusing the constant pool index 2242 // location for a native index into the ConstantPoolCache. 2243 // Since we are updating the constant pool index prior to 2244 // verification and ConstantPoolCache initialization, we 2245 // need to keep the new index in Java byte order. 2246 Bytes::put_Java_u2(p, new_index); 2247 } 2248 } break; 2249 default: 2250 break; 2251 } 2252 } // end for each bytecode 2253 } // end rewrite_cp_refs_in_method() 2254 2255 2256 // Rewrite constant pool references in the class_annotations field. 2257 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(InstanceKlass* scratch_class) { 2258 2259 AnnotationArray* class_annotations = scratch_class->class_annotations(); 2260 if (class_annotations == nullptr || class_annotations->length() == 0) { 2261 // no class_annotations so nothing to do 2262 return true; 2263 } 2264 2265 log_debug(redefine, class, annotation)("class_annotations length=%d", class_annotations->length()); 2266 2267 int byte_i = 0; // byte index into class_annotations 2268 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i); 2269 } 2270 2271 2272 // Rewrite constant pool references in an annotations typeArray. This 2273 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute 2274 // that is described in section 4.8.15 of the 2nd-edition of the VM spec: 2275 // 2276 // annotations_typeArray { 2277 // u2 num_annotations; 2278 // annotation annotations[num_annotations]; 2279 // } 2280 // 2281 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray( 2282 AnnotationArray* annotations_typeArray, int &byte_i_ref) { 2283 2284 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2285 // not enough room for num_annotations field 2286 log_debug(redefine, class, annotation)("length() is too small for num_annotations field"); 2287 return false; 2288 } 2289 2290 u2 num_annotations = Bytes::get_Java_u2((address) 2291 annotations_typeArray->adr_at(byte_i_ref)); 2292 byte_i_ref += 2; 2293 2294 log_debug(redefine, class, annotation)("num_annotations=%d", num_annotations); 2295 2296 int calc_num_annotations = 0; 2297 for (; calc_num_annotations < num_annotations; calc_num_annotations++) { 2298 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, byte_i_ref)) { 2299 log_debug(redefine, class, annotation)("bad annotation_struct at %d", calc_num_annotations); 2300 // propagate failure back to caller 2301 return false; 2302 } 2303 } 2304 assert(num_annotations == calc_num_annotations, "sanity check"); 2305 2306 return true; 2307 } // end rewrite_cp_refs_in_annotations_typeArray() 2308 2309 2310 // Rewrite constant pool references in the annotation struct portion of 2311 // an annotations_typeArray. This "structure" is from section 4.8.15 of 2312 // the 2nd-edition of the VM spec: 2313 // 2314 // struct annotation { 2315 // u2 type_index; 2316 // u2 num_element_value_pairs; 2317 // { 2318 // u2 element_name_index; 2319 // element_value value; 2320 // } element_value_pairs[num_element_value_pairs]; 2321 // } 2322 // 2323 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct( 2324 AnnotationArray* annotations_typeArray, int &byte_i_ref) { 2325 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) { 2326 // not enough room for smallest annotation_struct 2327 log_debug(redefine, class, annotation)("length() is too small for annotation_struct"); 2328 return false; 2329 } 2330 2331 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray, 2332 byte_i_ref, "type_index"); 2333 2334 u2 num_element_value_pairs = Bytes::get_Java_u2((address) 2335 annotations_typeArray->adr_at(byte_i_ref)); 2336 byte_i_ref += 2; 2337 2338 log_debug(redefine, class, annotation) 2339 ("type_index=%d num_element_value_pairs=%d", type_index, num_element_value_pairs); 2340 2341 int calc_num_element_value_pairs = 0; 2342 for (; calc_num_element_value_pairs < num_element_value_pairs; 2343 calc_num_element_value_pairs++) { 2344 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2345 // not enough room for another element_name_index, let alone 2346 // the rest of another component 2347 log_debug(redefine, class, annotation)("length() is too small for element_name_index"); 2348 return false; 2349 } 2350 2351 u2 element_name_index = rewrite_cp_ref_in_annotation_data( 2352 annotations_typeArray, byte_i_ref, 2353 "element_name_index"); 2354 2355 log_debug(redefine, class, annotation)("element_name_index=%d", element_name_index); 2356 2357 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, byte_i_ref)) { 2358 log_debug(redefine, class, annotation)("bad element_value at %d", calc_num_element_value_pairs); 2359 // propagate failure back to caller 2360 return false; 2361 } 2362 } // end for each component 2363 assert(num_element_value_pairs == calc_num_element_value_pairs, 2364 "sanity check"); 2365 2366 return true; 2367 } // end rewrite_cp_refs_in_annotation_struct() 2368 2369 2370 // Rewrite a constant pool reference at the current position in 2371 // annotations_typeArray if needed. Returns the original constant 2372 // pool reference if a rewrite was not needed or the new constant 2373 // pool reference if a rewrite was needed. 2374 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data( 2375 AnnotationArray* annotations_typeArray, int &byte_i_ref, 2376 const char * trace_mesg) { 2377 2378 address cp_index_addr = (address) 2379 annotations_typeArray->adr_at(byte_i_ref); 2380 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr); 2381 u2 new_cp_index = find_new_index(old_cp_index); 2382 if (new_cp_index != 0) { 2383 log_debug(redefine, class, annotation)("mapped old %s=%d", trace_mesg, old_cp_index); 2384 Bytes::put_Java_u2(cp_index_addr, new_cp_index); 2385 old_cp_index = new_cp_index; 2386 } 2387 byte_i_ref += 2; 2388 return old_cp_index; 2389 } 2390 2391 2392 // Rewrite constant pool references in the element_value portion of an 2393 // annotations_typeArray. This "structure" is from section 4.8.15.1 of 2394 // the 2nd-edition of the VM spec: 2395 // 2396 // struct element_value { 2397 // u1 tag; 2398 // union { 2399 // u2 const_value_index; 2400 // { 2401 // u2 type_name_index; 2402 // u2 const_name_index; 2403 // } enum_const_value; 2404 // u2 class_info_index; 2405 // annotation annotation_value; 2406 // struct { 2407 // u2 num_values; 2408 // element_value values[num_values]; 2409 // } array_value; 2410 // } value; 2411 // } 2412 // 2413 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value( 2414 AnnotationArray* annotations_typeArray, int &byte_i_ref) { 2415 2416 if ((byte_i_ref + 1) > annotations_typeArray->length()) { 2417 // not enough room for a tag let alone the rest of an element_value 2418 log_debug(redefine, class, annotation)("length() is too small for a tag"); 2419 return false; 2420 } 2421 2422 u1 tag = annotations_typeArray->at(byte_i_ref); 2423 byte_i_ref++; 2424 log_debug(redefine, class, annotation)("tag='%c'", tag); 2425 2426 switch (tag) { 2427 // These BaseType tag values are from Table 4.2 in VM spec: 2428 case JVM_SIGNATURE_BYTE: 2429 case JVM_SIGNATURE_CHAR: 2430 case JVM_SIGNATURE_DOUBLE: 2431 case JVM_SIGNATURE_FLOAT: 2432 case JVM_SIGNATURE_INT: 2433 case JVM_SIGNATURE_LONG: 2434 case JVM_SIGNATURE_SHORT: 2435 case JVM_SIGNATURE_BOOLEAN: 2436 2437 // The remaining tag values are from Table 4.8 in the 2nd-edition of 2438 // the VM spec: 2439 case 's': 2440 { 2441 // For the above tag values (including the BaseType values), 2442 // value.const_value_index is right union field. 2443 2444 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2445 // not enough room for a const_value_index 2446 log_debug(redefine, class, annotation)("length() is too small for a const_value_index"); 2447 return false; 2448 } 2449 2450 u2 const_value_index = rewrite_cp_ref_in_annotation_data( 2451 annotations_typeArray, byte_i_ref, 2452 "const_value_index"); 2453 2454 log_debug(redefine, class, annotation)("const_value_index=%d", const_value_index); 2455 } break; 2456 2457 case 'e': 2458 { 2459 // for the above tag value, value.enum_const_value is right union field 2460 2461 if ((byte_i_ref + 4) > annotations_typeArray->length()) { 2462 // not enough room for a enum_const_value 2463 log_debug(redefine, class, annotation)("length() is too small for a enum_const_value"); 2464 return false; 2465 } 2466 2467 u2 type_name_index = rewrite_cp_ref_in_annotation_data( 2468 annotations_typeArray, byte_i_ref, 2469 "type_name_index"); 2470 2471 u2 const_name_index = rewrite_cp_ref_in_annotation_data( 2472 annotations_typeArray, byte_i_ref, 2473 "const_name_index"); 2474 2475 log_debug(redefine, class, annotation) 2476 ("type_name_index=%d const_name_index=%d", type_name_index, const_name_index); 2477 } break; 2478 2479 case 'c': 2480 { 2481 // for the above tag value, value.class_info_index is right union field 2482 2483 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2484 // not enough room for a class_info_index 2485 log_debug(redefine, class, annotation)("length() is too small for a class_info_index"); 2486 return false; 2487 } 2488 2489 u2 class_info_index = rewrite_cp_ref_in_annotation_data( 2490 annotations_typeArray, byte_i_ref, 2491 "class_info_index"); 2492 2493 log_debug(redefine, class, annotation)("class_info_index=%d", class_info_index); 2494 } break; 2495 2496 case '@': 2497 // For the above tag value, value.attr_value is the right union 2498 // field. This is a nested annotation. 2499 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, byte_i_ref)) { 2500 // propagate failure back to caller 2501 return false; 2502 } 2503 break; 2504 2505 case JVM_SIGNATURE_ARRAY: 2506 { 2507 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2508 // not enough room for a num_values field 2509 log_debug(redefine, class, annotation)("length() is too small for a num_values field"); 2510 return false; 2511 } 2512 2513 // For the above tag value, value.array_value is the right union 2514 // field. This is an array of nested element_value. 2515 u2 num_values = Bytes::get_Java_u2((address) 2516 annotations_typeArray->adr_at(byte_i_ref)); 2517 byte_i_ref += 2; 2518 log_debug(redefine, class, annotation)("num_values=%d", num_values); 2519 2520 int calc_num_values = 0; 2521 for (; calc_num_values < num_values; calc_num_values++) { 2522 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, byte_i_ref)) { 2523 log_debug(redefine, class, annotation)("bad nested element_value at %d", calc_num_values); 2524 // propagate failure back to caller 2525 return false; 2526 } 2527 } 2528 assert(num_values == calc_num_values, "sanity check"); 2529 } break; 2530 2531 default: 2532 log_debug(redefine, class, annotation)("bad tag=0x%x", tag); 2533 return false; 2534 } // end decode tag field 2535 2536 return true; 2537 } // end rewrite_cp_refs_in_element_value() 2538 2539 2540 // Rewrite constant pool references in a fields_annotations field. 2541 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations( 2542 InstanceKlass* scratch_class) { 2543 2544 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations(); 2545 2546 if (fields_annotations == nullptr || fields_annotations->length() == 0) { 2547 // no fields_annotations so nothing to do 2548 return true; 2549 } 2550 2551 log_debug(redefine, class, annotation)("fields_annotations length=%d", fields_annotations->length()); 2552 2553 for (int i = 0; i < fields_annotations->length(); i++) { 2554 AnnotationArray* field_annotations = fields_annotations->at(i); 2555 if (field_annotations == nullptr || field_annotations->length() == 0) { 2556 // this field does not have any annotations so skip it 2557 continue; 2558 } 2559 2560 int byte_i = 0; // byte index into field_annotations 2561 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i)) { 2562 log_debug(redefine, class, annotation)("bad field_annotations at %d", i); 2563 // propagate failure back to caller 2564 return false; 2565 } 2566 } 2567 2568 return true; 2569 } // end rewrite_cp_refs_in_fields_annotations() 2570 2571 2572 // Rewrite constant pool references in a methods_annotations field. 2573 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations( 2574 InstanceKlass* scratch_class) { 2575 2576 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2577 Method* m = scratch_class->methods()->at(i); 2578 AnnotationArray* method_annotations = m->constMethod()->method_annotations(); 2579 2580 if (method_annotations == nullptr || method_annotations->length() == 0) { 2581 // this method does not have any annotations so skip it 2582 continue; 2583 } 2584 2585 int byte_i = 0; // byte index into method_annotations 2586 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i)) { 2587 log_debug(redefine, class, annotation)("bad method_annotations at %d", i); 2588 // propagate failure back to caller 2589 return false; 2590 } 2591 } 2592 2593 return true; 2594 } // end rewrite_cp_refs_in_methods_annotations() 2595 2596 2597 // Rewrite constant pool references in a methods_parameter_annotations 2598 // field. This "structure" is adapted from the 2599 // RuntimeVisibleParameterAnnotations_attribute described in section 2600 // 4.8.17 of the 2nd-edition of the VM spec: 2601 // 2602 // methods_parameter_annotations_typeArray { 2603 // u1 num_parameters; 2604 // { 2605 // u2 num_annotations; 2606 // annotation annotations[num_annotations]; 2607 // } parameter_annotations[num_parameters]; 2608 // } 2609 // 2610 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations( 2611 InstanceKlass* scratch_class) { 2612 2613 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2614 Method* m = scratch_class->methods()->at(i); 2615 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations(); 2616 if (method_parameter_annotations == nullptr 2617 || method_parameter_annotations->length() == 0) { 2618 // this method does not have any parameter annotations so skip it 2619 continue; 2620 } 2621 2622 if (method_parameter_annotations->length() < 1) { 2623 // not enough room for a num_parameters field 2624 log_debug(redefine, class, annotation)("length() is too small for a num_parameters field at %d", i); 2625 return false; 2626 } 2627 2628 int byte_i = 0; // byte index into method_parameter_annotations 2629 2630 u1 num_parameters = method_parameter_annotations->at(byte_i); 2631 byte_i++; 2632 2633 log_debug(redefine, class, annotation)("num_parameters=%d", num_parameters); 2634 2635 int calc_num_parameters = 0; 2636 for (; calc_num_parameters < num_parameters; calc_num_parameters++) { 2637 if (!rewrite_cp_refs_in_annotations_typeArray(method_parameter_annotations, byte_i)) { 2638 log_debug(redefine, class, annotation)("bad method_parameter_annotations at %d", calc_num_parameters); 2639 // propagate failure back to caller 2640 return false; 2641 } 2642 } 2643 assert(num_parameters == calc_num_parameters, "sanity check"); 2644 } 2645 2646 return true; 2647 } // end rewrite_cp_refs_in_methods_parameter_annotations() 2648 2649 2650 // Rewrite constant pool references in a methods_default_annotations 2651 // field. This "structure" is adapted from the AnnotationDefault_attribute 2652 // that is described in section 4.8.19 of the 2nd-edition of the VM spec: 2653 // 2654 // methods_default_annotations_typeArray { 2655 // element_value default_value; 2656 // } 2657 // 2658 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations( 2659 InstanceKlass* scratch_class) { 2660 2661 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2662 Method* m = scratch_class->methods()->at(i); 2663 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations(); 2664 if (method_default_annotations == nullptr 2665 || method_default_annotations->length() == 0) { 2666 // this method does not have any default annotations so skip it 2667 continue; 2668 } 2669 2670 int byte_i = 0; // byte index into method_default_annotations 2671 2672 if (!rewrite_cp_refs_in_element_value( 2673 method_default_annotations, byte_i)) { 2674 log_debug(redefine, class, annotation)("bad default element_value at %d", i); 2675 // propagate failure back to caller 2676 return false; 2677 } 2678 } 2679 2680 return true; 2681 } // end rewrite_cp_refs_in_methods_default_annotations() 2682 2683 2684 // Rewrite constant pool references in a class_type_annotations field. 2685 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations( 2686 InstanceKlass* scratch_class) { 2687 2688 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations(); 2689 if (class_type_annotations == nullptr || class_type_annotations->length() == 0) { 2690 // no class_type_annotations so nothing to do 2691 return true; 2692 } 2693 2694 log_debug(redefine, class, annotation)("class_type_annotations length=%d", class_type_annotations->length()); 2695 2696 int byte_i = 0; // byte index into class_type_annotations 2697 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations, 2698 byte_i, "ClassFile"); 2699 } // end rewrite_cp_refs_in_class_type_annotations() 2700 2701 2702 // Rewrite constant pool references in a fields_type_annotations field. 2703 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations(InstanceKlass* scratch_class) { 2704 2705 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations(); 2706 if (fields_type_annotations == nullptr || fields_type_annotations->length() == 0) { 2707 // no fields_type_annotations so nothing to do 2708 return true; 2709 } 2710 2711 log_debug(redefine, class, annotation)("fields_type_annotations length=%d", fields_type_annotations->length()); 2712 2713 for (int i = 0; i < fields_type_annotations->length(); i++) { 2714 AnnotationArray* field_type_annotations = fields_type_annotations->at(i); 2715 if (field_type_annotations == nullptr || field_type_annotations->length() == 0) { 2716 // this field does not have any annotations so skip it 2717 continue; 2718 } 2719 2720 int byte_i = 0; // byte index into field_type_annotations 2721 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations, 2722 byte_i, "field_info")) { 2723 log_debug(redefine, class, annotation)("bad field_type_annotations at %d", i); 2724 // propagate failure back to caller 2725 return false; 2726 } 2727 } 2728 2729 return true; 2730 } // end rewrite_cp_refs_in_fields_type_annotations() 2731 2732 2733 // Rewrite constant pool references in a methods_type_annotations field. 2734 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations( 2735 InstanceKlass* scratch_class) { 2736 2737 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2738 Method* m = scratch_class->methods()->at(i); 2739 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations(); 2740 2741 if (method_type_annotations == nullptr || method_type_annotations->length() == 0) { 2742 // this method does not have any annotations so skip it 2743 continue; 2744 } 2745 2746 log_debug(redefine, class, annotation)("methods type_annotations length=%d", method_type_annotations->length()); 2747 2748 int byte_i = 0; // byte index into method_type_annotations 2749 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations, 2750 byte_i, "method_info")) { 2751 log_debug(redefine, class, annotation)("bad method_type_annotations at %d", i); 2752 // propagate failure back to caller 2753 return false; 2754 } 2755 } 2756 2757 return true; 2758 } // end rewrite_cp_refs_in_methods_type_annotations() 2759 2760 2761 // Rewrite constant pool references in a type_annotations 2762 // field. This "structure" is adapted from the 2763 // RuntimeVisibleTypeAnnotations_attribute described in 2764 // section 4.7.20 of the Java SE 8 Edition of the VM spec: 2765 // 2766 // type_annotations_typeArray { 2767 // u2 num_annotations; 2768 // type_annotation annotations[num_annotations]; 2769 // } 2770 // 2771 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray( 2772 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2773 const char * location_mesg) { 2774 2775 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2776 // not enough room for num_annotations field 2777 log_debug(redefine, class, annotation)("length() is too small for num_annotations field"); 2778 return false; 2779 } 2780 2781 u2 num_annotations = Bytes::get_Java_u2((address) 2782 type_annotations_typeArray->adr_at(byte_i_ref)); 2783 byte_i_ref += 2; 2784 2785 log_debug(redefine, class, annotation)("num_type_annotations=%d", num_annotations); 2786 2787 int calc_num_annotations = 0; 2788 for (; calc_num_annotations < num_annotations; calc_num_annotations++) { 2789 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray, 2790 byte_i_ref, location_mesg)) { 2791 log_debug(redefine, class, annotation)("bad type_annotation_struct at %d", calc_num_annotations); 2792 // propagate failure back to caller 2793 return false; 2794 } 2795 } 2796 assert(num_annotations == calc_num_annotations, "sanity check"); 2797 2798 if (byte_i_ref != type_annotations_typeArray->length()) { 2799 log_debug(redefine, class, annotation) 2800 ("read wrong amount of bytes at end of processing type_annotations_typeArray (%d of %d bytes were read)", 2801 byte_i_ref, type_annotations_typeArray->length()); 2802 return false; 2803 } 2804 2805 return true; 2806 } // end rewrite_cp_refs_in_type_annotations_typeArray() 2807 2808 2809 // Rewrite constant pool references in a type_annotation 2810 // field. This "structure" is adapted from the 2811 // RuntimeVisibleTypeAnnotations_attribute described in 2812 // section 4.7.20 of the Java SE 8 Edition of the VM spec: 2813 // 2814 // type_annotation { 2815 // u1 target_type; 2816 // union { 2817 // type_parameter_target; 2818 // supertype_target; 2819 // type_parameter_bound_target; 2820 // empty_target; 2821 // method_formal_parameter_target; 2822 // throws_target; 2823 // localvar_target; 2824 // catch_target; 2825 // offset_target; 2826 // type_argument_target; 2827 // } target_info; 2828 // type_path target_path; 2829 // annotation anno; 2830 // } 2831 // 2832 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct( 2833 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2834 const char * location_mesg) { 2835 2836 if (!skip_type_annotation_target(type_annotations_typeArray, 2837 byte_i_ref, location_mesg)) { 2838 return false; 2839 } 2840 2841 if (!skip_type_annotation_type_path(type_annotations_typeArray, byte_i_ref)) { 2842 return false; 2843 } 2844 2845 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray, byte_i_ref)) { 2846 return false; 2847 } 2848 2849 return true; 2850 } // end rewrite_cp_refs_in_type_annotation_struct() 2851 2852 2853 // Read, verify and skip over the target_type and target_info part 2854 // so that rewriting can continue in the later parts of the struct. 2855 // 2856 // u1 target_type; 2857 // union { 2858 // type_parameter_target; 2859 // supertype_target; 2860 // type_parameter_bound_target; 2861 // empty_target; 2862 // method_formal_parameter_target; 2863 // throws_target; 2864 // localvar_target; 2865 // catch_target; 2866 // offset_target; 2867 // type_argument_target; 2868 // } target_info; 2869 // 2870 bool VM_RedefineClasses::skip_type_annotation_target( 2871 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2872 const char * location_mesg) { 2873 2874 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2875 // not enough room for a target_type let alone the rest of a type_annotation 2876 log_debug(redefine, class, annotation)("length() is too small for a target_type"); 2877 return false; 2878 } 2879 2880 u1 target_type = type_annotations_typeArray->at(byte_i_ref); 2881 byte_i_ref += 1; 2882 log_debug(redefine, class, annotation)("target_type=0x%.2x", target_type); 2883 log_debug(redefine, class, annotation)("location=%s", location_mesg); 2884 2885 // Skip over target_info 2886 switch (target_type) { 2887 case 0x00: 2888 // kind: type parameter declaration of generic class or interface 2889 // location: ClassFile 2890 case 0x01: 2891 // kind: type parameter declaration of generic method or constructor 2892 // location: method_info 2893 2894 { 2895 // struct: 2896 // type_parameter_target { 2897 // u1 type_parameter_index; 2898 // } 2899 // 2900 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2901 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_target"); 2902 return false; 2903 } 2904 2905 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2906 byte_i_ref += 1; 2907 2908 log_debug(redefine, class, annotation)("type_parameter_target: type_parameter_index=%d", type_parameter_index); 2909 } break; 2910 2911 case 0x10: 2912 // kind: type in extends clause of class or interface declaration 2913 // or in implements clause of interface declaration 2914 // location: ClassFile 2915 2916 { 2917 // struct: 2918 // supertype_target { 2919 // u2 supertype_index; 2920 // } 2921 // 2922 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2923 log_debug(redefine, class, annotation)("length() is too small for a supertype_target"); 2924 return false; 2925 } 2926 2927 u2 supertype_index = Bytes::get_Java_u2((address) 2928 type_annotations_typeArray->adr_at(byte_i_ref)); 2929 byte_i_ref += 2; 2930 2931 log_debug(redefine, class, annotation)("supertype_target: supertype_index=%d", supertype_index); 2932 } break; 2933 2934 case 0x11: 2935 // kind: type in bound of type parameter declaration of generic class or interface 2936 // location: ClassFile 2937 case 0x12: 2938 // kind: type in bound of type parameter declaration of generic method or constructor 2939 // location: method_info 2940 2941 { 2942 // struct: 2943 // type_parameter_bound_target { 2944 // u1 type_parameter_index; 2945 // u1 bound_index; 2946 // } 2947 // 2948 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2949 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_bound_target"); 2950 return false; 2951 } 2952 2953 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2954 byte_i_ref += 1; 2955 u1 bound_index = type_annotations_typeArray->at(byte_i_ref); 2956 byte_i_ref += 1; 2957 2958 log_debug(redefine, class, annotation) 2959 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d", type_parameter_index, bound_index); 2960 } break; 2961 2962 case 0x13: 2963 // kind: type in field declaration 2964 // location: field_info 2965 case 0x14: 2966 // kind: return type of method, or type of newly constructed object 2967 // location: method_info 2968 case 0x15: 2969 // kind: receiver type of method or constructor 2970 // location: method_info 2971 2972 { 2973 // struct: 2974 // empty_target { 2975 // } 2976 // 2977 log_debug(redefine, class, annotation)("empty_target"); 2978 } break; 2979 2980 case 0x16: 2981 // kind: type in formal parameter declaration of method, constructor, or lambda expression 2982 // location: method_info 2983 2984 { 2985 // struct: 2986 // formal_parameter_target { 2987 // u1 formal_parameter_index; 2988 // } 2989 // 2990 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2991 log_debug(redefine, class, annotation)("length() is too small for a formal_parameter_target"); 2992 return false; 2993 } 2994 2995 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2996 byte_i_ref += 1; 2997 2998 log_debug(redefine, class, annotation) 2999 ("formal_parameter_target: formal_parameter_index=%d", formal_parameter_index); 3000 } break; 3001 3002 case 0x17: 3003 // kind: type in throws clause of method or constructor 3004 // location: method_info 3005 3006 { 3007 // struct: 3008 // throws_target { 3009 // u2 throws_type_index 3010 // } 3011 // 3012 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 3013 log_debug(redefine, class, annotation)("length() is too small for a throws_target"); 3014 return false; 3015 } 3016 3017 u2 throws_type_index = Bytes::get_Java_u2((address) 3018 type_annotations_typeArray->adr_at(byte_i_ref)); 3019 byte_i_ref += 2; 3020 3021 log_debug(redefine, class, annotation)("throws_target: throws_type_index=%d", throws_type_index); 3022 } break; 3023 3024 case 0x40: 3025 // kind: type in local variable declaration 3026 // location: Code 3027 case 0x41: 3028 // kind: type in resource variable declaration 3029 // location: Code 3030 3031 { 3032 // struct: 3033 // localvar_target { 3034 // u2 table_length; 3035 // struct { 3036 // u2 start_pc; 3037 // u2 length; 3038 // u2 index; 3039 // } table[table_length]; 3040 // } 3041 // 3042 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 3043 // not enough room for a table_length let alone the rest of a localvar_target 3044 log_debug(redefine, class, annotation)("length() is too small for a localvar_target table_length"); 3045 return false; 3046 } 3047 3048 u2 table_length = Bytes::get_Java_u2((address) 3049 type_annotations_typeArray->adr_at(byte_i_ref)); 3050 byte_i_ref += 2; 3051 3052 log_debug(redefine, class, annotation)("localvar_target: table_length=%d", table_length); 3053 3054 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry 3055 int table_size = table_length * table_struct_size; 3056 3057 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) { 3058 // not enough room for a table 3059 log_debug(redefine, class, annotation)("length() is too small for a table array of length %d", table_length); 3060 return false; 3061 } 3062 3063 // Skip over table 3064 byte_i_ref += table_size; 3065 } break; 3066 3067 case 0x42: 3068 // kind: type in exception parameter declaration 3069 // location: Code 3070 3071 { 3072 // struct: 3073 // catch_target { 3074 // u2 exception_table_index; 3075 // } 3076 // 3077 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 3078 log_debug(redefine, class, annotation)("length() is too small for a catch_target"); 3079 return false; 3080 } 3081 3082 u2 exception_table_index = Bytes::get_Java_u2((address) 3083 type_annotations_typeArray->adr_at(byte_i_ref)); 3084 byte_i_ref += 2; 3085 3086 log_debug(redefine, class, annotation)("catch_target: exception_table_index=%d", exception_table_index); 3087 } break; 3088 3089 case 0x43: 3090 // kind: type in instanceof expression 3091 // location: Code 3092 case 0x44: 3093 // kind: type in new expression 3094 // location: Code 3095 case 0x45: 3096 // kind: type in method reference expression using ::new 3097 // location: Code 3098 case 0x46: 3099 // kind: type in method reference expression using ::Identifier 3100 // location: Code 3101 3102 { 3103 // struct: 3104 // offset_target { 3105 // u2 offset; 3106 // } 3107 // 3108 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 3109 log_debug(redefine, class, annotation)("length() is too small for a offset_target"); 3110 return false; 3111 } 3112 3113 u2 offset = Bytes::get_Java_u2((address) 3114 type_annotations_typeArray->adr_at(byte_i_ref)); 3115 byte_i_ref += 2; 3116 3117 log_debug(redefine, class, annotation)("offset_target: offset=%d", offset); 3118 } break; 3119 3120 case 0x47: 3121 // kind: type in cast expression 3122 // location: Code 3123 case 0x48: 3124 // kind: type argument for generic constructor in new expression or 3125 // explicit constructor invocation statement 3126 // location: Code 3127 case 0x49: 3128 // kind: type argument for generic method in method invocation expression 3129 // location: Code 3130 case 0x4A: 3131 // kind: type argument for generic constructor in method reference expression using ::new 3132 // location: Code 3133 case 0x4B: 3134 // kind: type argument for generic method in method reference expression using ::Identifier 3135 // location: Code 3136 3137 { 3138 // struct: 3139 // type_argument_target { 3140 // u2 offset; 3141 // u1 type_argument_index; 3142 // } 3143 // 3144 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) { 3145 log_debug(redefine, class, annotation)("length() is too small for a type_argument_target"); 3146 return false; 3147 } 3148 3149 u2 offset = Bytes::get_Java_u2((address) 3150 type_annotations_typeArray->adr_at(byte_i_ref)); 3151 byte_i_ref += 2; 3152 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref); 3153 byte_i_ref += 1; 3154 3155 log_debug(redefine, class, annotation) 3156 ("type_argument_target: offset=%d, type_argument_index=%d", offset, type_argument_index); 3157 } break; 3158 3159 default: 3160 log_debug(redefine, class, annotation)("unknown target_type"); 3161 #ifdef ASSERT 3162 ShouldNotReachHere(); 3163 #endif 3164 return false; 3165 } 3166 3167 return true; 3168 } // end skip_type_annotation_target() 3169 3170 3171 // Read, verify and skip over the type_path part so that rewriting 3172 // can continue in the later parts of the struct. 3173 // 3174 // type_path { 3175 // u1 path_length; 3176 // { 3177 // u1 type_path_kind; 3178 // u1 type_argument_index; 3179 // } path[path_length]; 3180 // } 3181 // 3182 bool VM_RedefineClasses::skip_type_annotation_type_path( 3183 AnnotationArray* type_annotations_typeArray, int &byte_i_ref) { 3184 3185 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 3186 // not enough room for a path_length let alone the rest of the type_path 3187 log_debug(redefine, class, annotation)("length() is too small for a type_path"); 3188 return false; 3189 } 3190 3191 u1 path_length = type_annotations_typeArray->at(byte_i_ref); 3192 byte_i_ref += 1; 3193 3194 log_debug(redefine, class, annotation)("type_path: path_length=%d", path_length); 3195 3196 int calc_path_length = 0; 3197 for (; calc_path_length < path_length; calc_path_length++) { 3198 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) { 3199 // not enough room for a path 3200 log_debug(redefine, class, annotation) 3201 ("length() is too small for path entry %d of %d", calc_path_length, path_length); 3202 return false; 3203 } 3204 3205 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref); 3206 byte_i_ref += 1; 3207 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref); 3208 byte_i_ref += 1; 3209 3210 log_debug(redefine, class, annotation) 3211 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d", 3212 calc_path_length, type_path_kind, type_argument_index); 3213 3214 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) { 3215 // not enough room for a path 3216 log_debug(redefine, class, annotation)("inconsistent type_path values"); 3217 return false; 3218 } 3219 } 3220 assert(path_length == calc_path_length, "sanity check"); 3221 3222 return true; 3223 } // end skip_type_annotation_type_path() 3224 3225 3226 // Rewrite constant pool references in the method's stackmap table. 3227 // These "structures" are adapted from the StackMapTable_attribute that 3228 // is described in section 4.8.4 of the 6.0 version of the VM spec 3229 // (dated 2005.10.26): 3230 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf 3231 // 3232 // stack_map { 3233 // u2 number_of_entries; 3234 // stack_map_frame entries[number_of_entries]; 3235 // } 3236 // 3237 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table( 3238 const methodHandle& method) { 3239 3240 if (!method->has_stackmap_table()) { 3241 return; 3242 } 3243 3244 AnnotationArray* stackmap_data = method->stackmap_data(); 3245 address stackmap_p = (address)stackmap_data->adr_at(0); 3246 address stackmap_end = stackmap_p + stackmap_data->length(); 3247 3248 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries"); 3249 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p); 3250 stackmap_p += 2; 3251 3252 log_debug(redefine, class, stackmap)("number_of_entries=%u", number_of_entries); 3253 3254 // walk through each stack_map_frame 3255 u2 calc_number_of_entries = 0; 3256 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) { 3257 // The stack_map_frame structure is a u1 frame_type followed by 3258 // 0 or more bytes of data: 3259 // 3260 // union stack_map_frame { 3261 // same_frame; 3262 // same_locals_1_stack_item_frame; 3263 // same_locals_1_stack_item_frame_extended; 3264 // chop_frame; 3265 // same_frame_extended; 3266 // append_frame; 3267 // full_frame; 3268 // } 3269 3270 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type"); 3271 u1 frame_type = *stackmap_p; 3272 stackmap_p++; 3273 3274 // same_frame { 3275 // u1 frame_type = SAME; /* 0-63 */ 3276 // } 3277 if (frame_type <= 63) { 3278 // nothing more to do for same_frame 3279 } 3280 3281 // same_locals_1_stack_item_frame { 3282 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */ 3283 // verification_type_info stack[1]; 3284 // } 3285 else if (frame_type >= 64 && frame_type <= 127) { 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 >= 128 && frame_type <= 246) { 3292 // nothing more to do for reserved frame_types 3293 } 3294 3295 // same_locals_1_stack_item_frame_extended { 3296 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */ 3297 // u2 offset_delta; 3298 // verification_type_info stack[1]; 3299 // } 3300 else if (frame_type == 247) { 3301 stackmap_p += 2; 3302 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3303 calc_number_of_entries, frame_type); 3304 } 3305 3306 // chop_frame { 3307 // u1 frame_type = CHOP; /* 248-250 */ 3308 // u2 offset_delta; 3309 // } 3310 else if (frame_type >= 248 && frame_type <= 250) { 3311 stackmap_p += 2; 3312 } 3313 3314 // same_frame_extended { 3315 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/ 3316 // u2 offset_delta; 3317 // } 3318 else if (frame_type == 251) { 3319 stackmap_p += 2; 3320 } 3321 3322 // append_frame { 3323 // u1 frame_type = APPEND; /* 252-254 */ 3324 // u2 offset_delta; 3325 // verification_type_info locals[frame_type - 251]; 3326 // } 3327 else if (frame_type >= 252 && frame_type <= 254) { 3328 assert(stackmap_p + 2 <= stackmap_end, 3329 "no room for offset_delta"); 3330 stackmap_p += 2; 3331 u1 len = frame_type - 251; 3332 for (u1 i = 0; i < len; i++) { 3333 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3334 calc_number_of_entries, frame_type); 3335 } 3336 } 3337 3338 // full_frame { 3339 // u1 frame_type = FULL_FRAME; /* 255 */ 3340 // u2 offset_delta; 3341 // u2 number_of_locals; 3342 // verification_type_info locals[number_of_locals]; 3343 // u2 number_of_stack_items; 3344 // verification_type_info stack[number_of_stack_items]; 3345 // } 3346 else if (frame_type == 255) { 3347 assert(stackmap_p + 2 + 2 <= stackmap_end, 3348 "no room for smallest full_frame"); 3349 stackmap_p += 2; 3350 3351 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p); 3352 stackmap_p += 2; 3353 3354 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) { 3355 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3356 calc_number_of_entries, frame_type); 3357 } 3358 3359 // Use the largest size for the number_of_stack_items, but only get 3360 // the right number of bytes. 3361 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p); 3362 stackmap_p += 2; 3363 3364 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) { 3365 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3366 calc_number_of_entries, frame_type); 3367 } 3368 } 3369 } // end while there is a stack_map_frame 3370 assert(number_of_entries == calc_number_of_entries, "sanity check"); 3371 } // end rewrite_cp_refs_in_stack_map_table() 3372 3373 3374 // Rewrite constant pool references in the verification type info 3375 // portion of the method's stackmap table. These "structures" are 3376 // adapted from the StackMapTable_attribute that is described in 3377 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26): 3378 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf 3379 // 3380 // The verification_type_info structure is a u1 tag followed by 0 or 3381 // more bytes of data: 3382 // 3383 // union verification_type_info { 3384 // Top_variable_info; 3385 // Integer_variable_info; 3386 // Float_variable_info; 3387 // Long_variable_info; 3388 // Double_variable_info; 3389 // Null_variable_info; 3390 // UninitializedThis_variable_info; 3391 // Object_variable_info; 3392 // Uninitialized_variable_info; 3393 // } 3394 // 3395 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info( 3396 address& stackmap_p_ref, address stackmap_end, u2 frame_i, 3397 u1 frame_type) { 3398 3399 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag"); 3400 u1 tag = *stackmap_p_ref; 3401 stackmap_p_ref++; 3402 3403 switch (tag) { 3404 // Top_variable_info { 3405 // u1 tag = ITEM_Top; /* 0 */ 3406 // } 3407 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top 3408 case 0: // fall through 3409 3410 // Integer_variable_info { 3411 // u1 tag = ITEM_Integer; /* 1 */ 3412 // } 3413 case ITEM_Integer: // fall through 3414 3415 // Float_variable_info { 3416 // u1 tag = ITEM_Float; /* 2 */ 3417 // } 3418 case ITEM_Float: // fall through 3419 3420 // Double_variable_info { 3421 // u1 tag = ITEM_Double; /* 3 */ 3422 // } 3423 case ITEM_Double: // fall through 3424 3425 // Long_variable_info { 3426 // u1 tag = ITEM_Long; /* 4 */ 3427 // } 3428 case ITEM_Long: // fall through 3429 3430 // Null_variable_info { 3431 // u1 tag = ITEM_Null; /* 5 */ 3432 // } 3433 case ITEM_Null: // fall through 3434 3435 // UninitializedThis_variable_info { 3436 // u1 tag = ITEM_UninitializedThis; /* 6 */ 3437 // } 3438 case ITEM_UninitializedThis: 3439 // nothing more to do for the above tag types 3440 break; 3441 3442 // Object_variable_info { 3443 // u1 tag = ITEM_Object; /* 7 */ 3444 // u2 cpool_index; 3445 // } 3446 case ITEM_Object: 3447 { 3448 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index"); 3449 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref); 3450 u2 new_cp_index = find_new_index(cpool_index); 3451 if (new_cp_index != 0) { 3452 log_debug(redefine, class, stackmap)("mapped old cpool_index=%d", cpool_index); 3453 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index); 3454 cpool_index = new_cp_index; 3455 } 3456 stackmap_p_ref += 2; 3457 3458 log_debug(redefine, class, stackmap) 3459 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i, frame_type, cpool_index); 3460 } break; 3461 3462 // Uninitialized_variable_info { 3463 // u1 tag = ITEM_Uninitialized; /* 8 */ 3464 // u2 offset; 3465 // } 3466 case ITEM_Uninitialized: 3467 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset"); 3468 stackmap_p_ref += 2; 3469 break; 3470 3471 default: 3472 log_debug(redefine, class, stackmap)("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag); 3473 ShouldNotReachHere(); 3474 break; 3475 } // end switch (tag) 3476 } // end rewrite_cp_refs_in_verification_type_info() 3477 3478 3479 // Change the constant pool associated with klass scratch_class to scratch_cp. 3480 // scratch_cp_length elements are copied from scratch_cp to a smaller constant pool 3481 // and the smaller constant pool is associated with scratch_class. 3482 void VM_RedefineClasses::set_new_constant_pool( 3483 ClassLoaderData* loader_data, 3484 InstanceKlass* scratch_class, constantPoolHandle scratch_cp, 3485 int scratch_cp_length, TRAPS) { 3486 assert(scratch_cp->length() >= scratch_cp_length, "sanity check"); 3487 3488 // scratch_cp is a merged constant pool and has enough space for a 3489 // worst case merge situation. We want to associate the minimum 3490 // sized constant pool with the klass to save space. 3491 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK); 3492 constantPoolHandle smaller_cp(THREAD, cp); 3493 3494 // preserve version() value in the smaller copy 3495 int version = scratch_cp->version(); 3496 assert(version != 0, "sanity check"); 3497 smaller_cp->set_version(version); 3498 3499 // attach klass to new constant pool 3500 // reference to the cp holder is needed for copy_operands() 3501 smaller_cp->set_pool_holder(scratch_class); 3502 3503 smaller_cp->copy_fields(scratch_cp()); 3504 3505 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD); 3506 if (HAS_PENDING_EXCEPTION) { 3507 // Exception is handled in the caller 3508 loader_data->add_to_deallocate_list(smaller_cp()); 3509 return; 3510 } 3511 scratch_cp = smaller_cp; 3512 3513 // attach new constant pool to klass 3514 scratch_class->set_constants(scratch_cp()); 3515 scratch_cp->initialize_unresolved_klasses(loader_data, CHECK); 3516 3517 int i; // for portability 3518 3519 // update each field in klass to use new constant pool indices as needed 3520 int java_fields; 3521 int injected_fields; 3522 bool update_required = false; 3523 GrowableArray<FieldInfo>* fields = FieldInfoStream::create_FieldInfoArray(scratch_class->fieldinfo_stream(), &java_fields, &injected_fields); 3524 for (int i = 0; i < java_fields; i++) { 3525 FieldInfo* fi = fields->adr_at(i); 3526 jshort cur_index = fi->name_index(); 3527 jshort new_index = find_new_index(cur_index); 3528 if (new_index != 0) { 3529 log_trace(redefine, class, constantpool)("field-name_index change: %d to %d", cur_index, new_index); 3530 fi->set_name_index(new_index); 3531 update_required = true; 3532 } 3533 cur_index = fi->signature_index(); 3534 new_index = find_new_index(cur_index); 3535 if (new_index != 0) { 3536 log_trace(redefine, class, constantpool)("field-signature_index change: %d to %d", cur_index, new_index); 3537 fi->set_signature_index(new_index); 3538 update_required = true; 3539 } 3540 cur_index = fi->initializer_index(); 3541 new_index = find_new_index(cur_index); 3542 if (new_index != 0) { 3543 log_trace(redefine, class, constantpool)("field-initval_index change: %d to %d", cur_index, new_index); 3544 fi->set_initializer_index(new_index); 3545 update_required = true; 3546 } 3547 cur_index = fi->generic_signature_index(); 3548 new_index = find_new_index(cur_index); 3549 if (new_index != 0) { 3550 log_trace(redefine, class, constantpool)("field-generic_signature change: %d to %d", cur_index, new_index); 3551 fi->set_generic_signature_index(new_index); 3552 update_required = true; 3553 } 3554 } 3555 if (update_required) { 3556 Array<u1>* old_stream = scratch_class->fieldinfo_stream(); 3557 assert(fields->length() == (java_fields + injected_fields), "Must be"); 3558 Array<u1>* new_fis = FieldInfoStream::create_FieldInfoStream(fields, java_fields, injected_fields, scratch_class->class_loader_data(), CHECK); 3559 scratch_class->set_fieldinfo_stream(new_fis); 3560 MetadataFactory::free_array<u1>(scratch_class->class_loader_data(), old_stream); 3561 } 3562 3563 // Update constant pool indices in the inner classes info to use 3564 // new constant indices as needed. The inner classes info is a 3565 // quadruple: 3566 // (inner_class_info, outer_class_info, inner_name, inner_access_flags) 3567 InnerClassesIterator iter(scratch_class); 3568 for (; !iter.done(); iter.next()) { 3569 int cur_index = iter.inner_class_info_index(); 3570 if (cur_index == 0) { 3571 continue; // JVM spec. allows null inner class refs so skip it 3572 } 3573 u2 new_index = find_new_index(cur_index); 3574 if (new_index != 0) { 3575 log_trace(redefine, class, constantpool)("inner_class_info change: %d to %d", cur_index, new_index); 3576 iter.set_inner_class_info_index(new_index); 3577 } 3578 cur_index = iter.outer_class_info_index(); 3579 new_index = find_new_index(cur_index); 3580 if (new_index != 0) { 3581 log_trace(redefine, class, constantpool)("outer_class_info change: %d to %d", cur_index, new_index); 3582 iter.set_outer_class_info_index(new_index); 3583 } 3584 cur_index = iter.inner_name_index(); 3585 new_index = find_new_index(cur_index); 3586 if (new_index != 0) { 3587 log_trace(redefine, class, constantpool)("inner_name change: %d to %d", cur_index, new_index); 3588 iter.set_inner_name_index(new_index); 3589 } 3590 } // end for each inner class 3591 3592 // Attach each method in klass to the new constant pool and update 3593 // to use new constant pool indices as needed: 3594 Array<Method*>* methods = scratch_class->methods(); 3595 for (i = methods->length() - 1; i >= 0; i--) { 3596 methodHandle method(THREAD, methods->at(i)); 3597 method->set_constants(scratch_cp()); 3598 3599 u2 new_index = find_new_index(method->name_index()); 3600 if (new_index != 0) { 3601 log_trace(redefine, class, constantpool) 3602 ("method-name_index change: %d to %d", method->name_index(), new_index); 3603 method->set_name_index(new_index); 3604 } 3605 new_index = find_new_index(method->signature_index()); 3606 if (new_index != 0) { 3607 log_trace(redefine, class, constantpool) 3608 ("method-signature_index change: %d to %d", method->signature_index(), new_index); 3609 method->set_signature_index(new_index); 3610 } 3611 new_index = find_new_index(method->generic_signature_index()); 3612 if (new_index != 0) { 3613 log_trace(redefine, class, constantpool) 3614 ("method-generic_signature_index change: %d to %d", method->generic_signature_index(), new_index); 3615 method->constMethod()->set_generic_signature_index(new_index); 3616 } 3617 3618 // Update constant pool indices in the method's checked exception 3619 // table to use new constant indices as needed. 3620 int cext_length = method->checked_exceptions_length(); 3621 if (cext_length > 0) { 3622 CheckedExceptionElement * cext_table = 3623 method->checked_exceptions_start(); 3624 for (int j = 0; j < cext_length; j++) { 3625 int cur_index = cext_table[j].class_cp_index; 3626 int new_index = find_new_index(cur_index); 3627 if (new_index != 0) { 3628 log_trace(redefine, class, constantpool)("cext-class_cp_index change: %d to %d", cur_index, new_index); 3629 cext_table[j].class_cp_index = (u2)new_index; 3630 } 3631 } // end for each checked exception table entry 3632 } // end if there are checked exception table entries 3633 3634 // Update each catch type index in the method's exception table 3635 // to use new constant pool indices as needed. The exception table 3636 // holds quadruple entries of the form: 3637 // (beg_bci, end_bci, handler_bci, klass_index) 3638 3639 ExceptionTable ex_table(method()); 3640 int ext_length = ex_table.length(); 3641 3642 for (int j = 0; j < ext_length; j ++) { 3643 int cur_index = ex_table.catch_type_index(j); 3644 u2 new_index = find_new_index(cur_index); 3645 if (new_index != 0) { 3646 log_trace(redefine, class, constantpool)("ext-klass_index change: %d to %d", cur_index, new_index); 3647 ex_table.set_catch_type_index(j, new_index); 3648 } 3649 } // end for each exception table entry 3650 3651 // Update constant pool indices in the method's local variable 3652 // table to use new constant indices as needed. The local variable 3653 // table hold sextuple entries of the form: 3654 // (start_pc, length, name_index, descriptor_index, signature_index, slot) 3655 int lvt_length = method->localvariable_table_length(); 3656 if (lvt_length > 0) { 3657 LocalVariableTableElement * lv_table = 3658 method->localvariable_table_start(); 3659 for (int j = 0; j < lvt_length; j++) { 3660 int cur_index = lv_table[j].name_cp_index; 3661 int new_index = find_new_index(cur_index); 3662 if (new_index != 0) { 3663 log_trace(redefine, class, constantpool)("lvt-name_cp_index change: %d to %d", cur_index, new_index); 3664 lv_table[j].name_cp_index = (u2)new_index; 3665 } 3666 cur_index = lv_table[j].descriptor_cp_index; 3667 new_index = find_new_index(cur_index); 3668 if (new_index != 0) { 3669 log_trace(redefine, class, constantpool)("lvt-descriptor_cp_index change: %d to %d", cur_index, new_index); 3670 lv_table[j].descriptor_cp_index = (u2)new_index; 3671 } 3672 cur_index = lv_table[j].signature_cp_index; 3673 new_index = find_new_index(cur_index); 3674 if (new_index != 0) { 3675 log_trace(redefine, class, constantpool)("lvt-signature_cp_index change: %d to %d", cur_index, new_index); 3676 lv_table[j].signature_cp_index = (u2)new_index; 3677 } 3678 } // end for each local variable table entry 3679 } // end if there are local variable table entries 3680 3681 // Update constant pool indices in the method's method_parameters. 3682 int mp_length = method->method_parameters_length(); 3683 if (mp_length > 0) { 3684 MethodParametersElement* elem = method->method_parameters_start(); 3685 for (int j = 0; j < mp_length; j++) { 3686 const int cp_index = elem[j].name_cp_index; 3687 const int new_cp_index = find_new_index(cp_index); 3688 if (new_cp_index != 0) { 3689 elem[j].name_cp_index = (u2)new_cp_index; 3690 } 3691 } 3692 } 3693 3694 rewrite_cp_refs_in_stack_map_table(method); 3695 } // end for each method 3696 } // end set_new_constant_pool() 3697 3698 3699 // Unevolving classes may point to methods of the_class directly 3700 // from their constant pool caches, itables, and/or vtables. We 3701 // use the ClassLoaderDataGraph::classes_do() facility and this helper 3702 // to fix up these pointers. MethodData also points to old methods and 3703 // must be cleaned. 3704 3705 // Adjust cpools and vtables closure 3706 void VM_RedefineClasses::AdjustAndCleanMetadata::do_klass(Klass* k) { 3707 3708 // This is a very busy routine. We don't want too much tracing 3709 // printed out. 3710 bool trace_name_printed = false; 3711 3712 // If the class being redefined is java.lang.Object, we need to fix all 3713 // array class vtables also. The _has_redefined_Object flag is global. 3714 // Once the java.lang.Object has been redefined (by the current or one 3715 // of the previous VM_RedefineClasses operations) we have to always 3716 // adjust method entries for array classes. 3717 if (k->is_array_klass() && _has_redefined_Object) { 3718 k->vtable().adjust_method_entries(&trace_name_printed); 3719 3720 } else if (k->is_instance_klass()) { 3721 HandleMark hm(_thread); 3722 InstanceKlass *ik = InstanceKlass::cast(k); 3723 3724 // Clean MethodData of this class's methods so they don't refer to 3725 // old methods that are no longer running. 3726 Array<Method*>* methods = ik->methods(); 3727 int num_methods = methods->length(); 3728 for (int index = 0; index < num_methods; ++index) { 3729 if (methods->at(index)->method_data() != nullptr) { 3730 methods->at(index)->method_data()->clean_weak_method_links(); 3731 } 3732 } 3733 3734 // Adjust all vtables, default methods and itables, to clean out old methods. 3735 ResourceMark rm(_thread); 3736 if (ik->vtable_length() > 0) { 3737 ik->vtable().adjust_method_entries(&trace_name_printed); 3738 ik->adjust_default_methods(&trace_name_printed); 3739 } 3740 3741 if (ik->itable_length() > 0) { 3742 ik->itable().adjust_method_entries(&trace_name_printed); 3743 } 3744 3745 // The constant pools in other classes (other_cp) can refer to 3746 // old methods. We have to update method information in 3747 // other_cp's cache. If other_cp has a previous version, then we 3748 // have to repeat the process for each previous version. The 3749 // constant pool cache holds the Method*s for non-virtual 3750 // methods and for virtual, final methods. 3751 // 3752 // Special case: if the current class is being redefined by the current 3753 // VM_RedefineClasses operation, then new_cp has already been attached 3754 // to the_class and old_cp has already been added as a previous version. 3755 // The new_cp doesn't have any cached references to old methods so it 3756 // doesn't need to be updated and we could optimize by skipping it. 3757 // However, the current class can be marked as being redefined by another 3758 // VM_RedefineClasses operation which has already executed its doit_prologue 3759 // and needs cpcache method entries adjusted. For simplicity, the cpcache 3760 // update is done unconditionally. It should result in doing nothing for 3761 // classes being redefined by the current VM_RedefineClasses operation. 3762 // Method entries in the previous version(s) are adjusted as well. 3763 ConstantPoolCache* cp_cache; 3764 3765 // this klass' constant pool cache may need adjustment 3766 ConstantPool* other_cp = ik->constants(); 3767 cp_cache = other_cp->cache(); 3768 if (cp_cache != nullptr) { 3769 cp_cache->adjust_method_entries(&trace_name_printed); 3770 } 3771 3772 // the previous versions' constant pool caches may need adjustment 3773 for (InstanceKlass* pv_node = ik->previous_versions(); 3774 pv_node != nullptr; 3775 pv_node = pv_node->previous_versions()) { 3776 cp_cache = pv_node->constants()->cache(); 3777 if (cp_cache != nullptr) { 3778 cp_cache->adjust_method_entries(&trace_name_printed); 3779 } 3780 } 3781 } 3782 } 3783 3784 void VM_RedefineClasses::update_jmethod_ids() { 3785 for (int j = 0; j < _matching_methods_length; ++j) { 3786 Method* old_method = _matching_old_methods[j]; 3787 jmethodID jmid = old_method->find_jmethod_id_or_null(); 3788 if (jmid != nullptr) { 3789 // There is a jmethodID, change it to point to the new method 3790 Method* new_method = _matching_new_methods[j]; 3791 Method::change_method_associated_with_jmethod_id(jmid, new_method); 3792 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j], 3793 "should be replaced"); 3794 } 3795 } 3796 } 3797 3798 int VM_RedefineClasses::check_methods_and_mark_as_obsolete() { 3799 int emcp_method_count = 0; 3800 int obsolete_count = 0; 3801 int old_index = 0; 3802 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) { 3803 Method* old_method = _matching_old_methods[j]; 3804 Method* new_method = _matching_new_methods[j]; 3805 Method* old_array_method; 3806 3807 // Maintain an old_index into the _old_methods array by skipping 3808 // deleted methods 3809 while ((old_array_method = _old_methods->at(old_index)) != old_method) { 3810 ++old_index; 3811 } 3812 3813 if (MethodComparator::methods_EMCP(old_method, new_method)) { 3814 // The EMCP definition from JSR-163 requires the bytecodes to be 3815 // the same with the exception of constant pool indices which may 3816 // differ. However, the constants referred to by those indices 3817 // must be the same. 3818 // 3819 // We use methods_EMCP() for comparison since constant pool 3820 // merging can remove duplicate constant pool entries that were 3821 // present in the old method and removed from the rewritten new 3822 // method. A faster binary comparison function would consider the 3823 // old and new methods to be different when they are actually 3824 // EMCP. 3825 // 3826 // The old and new methods are EMCP and you would think that we 3827 // could get rid of one of them here and now and save some space. 3828 // However, the concept of EMCP only considers the bytecodes and 3829 // the constant pool entries in the comparison. Other things, 3830 // e.g., the line number table (LNT) or the local variable table 3831 // (LVT) don't count in the comparison. So the new (and EMCP) 3832 // method can have a new LNT that we need so we can't just 3833 // overwrite the new method with the old method. 3834 // 3835 // When this routine is called, we have already attached the new 3836 // methods to the_class so the old methods are effectively 3837 // overwritten. However, if an old method is still executing, 3838 // then the old method cannot be collected until sometime after 3839 // the old method call has returned. So the overwriting of old 3840 // methods by new methods will save us space except for those 3841 // (hopefully few) old methods that are still executing. 3842 // 3843 // A method refers to a ConstMethod* and this presents another 3844 // possible avenue to space savings. The ConstMethod* in the 3845 // new method contains possibly new attributes (LNT, LVT, etc). 3846 // At first glance, it seems possible to save space by replacing 3847 // the ConstMethod* in the old method with the ConstMethod* 3848 // from the new method. The old and new methods would share the 3849 // same ConstMethod* and we would save the space occupied by 3850 // the old ConstMethod*. However, the ConstMethod* contains 3851 // a back reference to the containing method. Sharing the 3852 // ConstMethod* between two methods could lead to confusion in 3853 // the code that uses the back reference. This would lead to 3854 // brittle code that could be broken in non-obvious ways now or 3855 // in the future. 3856 // 3857 // Another possibility is to copy the ConstMethod* from the new 3858 // method to the old method and then overwrite the new method with 3859 // the old method. Since the ConstMethod* contains the bytecodes 3860 // for the method embedded in the oop, this option would change 3861 // the bytecodes out from under any threads executing the old 3862 // method and make the thread's bcp invalid. Since EMCP requires 3863 // that the bytecodes be the same modulo constant pool indices, it 3864 // is straight forward to compute the correct new bcp in the new 3865 // ConstMethod* from the old bcp in the old ConstMethod*. The 3866 // time consuming part would be searching all the frames in all 3867 // of the threads to find all of the calls to the old method. 3868 // 3869 // It looks like we will have to live with the limited savings 3870 // that we get from effectively overwriting the old methods 3871 // when the new methods are attached to the_class. 3872 3873 // Count number of methods that are EMCP. The method will be marked 3874 // old but not obsolete if it is EMCP. 3875 emcp_method_count++; 3876 3877 // An EMCP method is _not_ obsolete. An obsolete method has a 3878 // different jmethodID than the current method. An EMCP method 3879 // has the same jmethodID as the current method. Having the 3880 // same jmethodID for all EMCP versions of a method allows for 3881 // a consistent view of the EMCP methods regardless of which 3882 // EMCP method you happen to have in hand. For example, a 3883 // breakpoint set in one EMCP method will work for all EMCP 3884 // versions of the method including the current one. 3885 } else { 3886 // mark obsolete methods as such 3887 old_method->set_is_obsolete(); 3888 obsolete_count++; 3889 3890 // obsolete methods need a unique idnum so they become new entries in 3891 // the jmethodID cache in InstanceKlass 3892 assert(old_method->method_idnum() == new_method->method_idnum(), "must match"); 3893 u2 num = InstanceKlass::cast(_the_class)->next_method_idnum(); 3894 if (num != ConstMethod::UNSET_IDNUM) { 3895 old_method->set_method_idnum(num); 3896 } 3897 3898 // With tracing we try not to "yack" too much. The position of 3899 // this trace assumes there are fewer obsolete methods than 3900 // EMCP methods. 3901 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) { 3902 ResourceMark rm; 3903 log_trace(redefine, class, obsolete, mark) 3904 ("mark %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string()); 3905 } 3906 } 3907 old_method->set_is_old(); 3908 } 3909 for (int i = 0; i < _deleted_methods_length; ++i) { 3910 Method* old_method = _deleted_methods[i]; 3911 3912 assert(!old_method->has_vtable_index(), 3913 "cannot delete methods with vtable entries");; 3914 3915 // Mark all deleted methods as old, obsolete and deleted 3916 old_method->set_is_deleted(); 3917 old_method->set_is_old(); 3918 old_method->set_is_obsolete(); 3919 ++obsolete_count; 3920 // With tracing we try not to "yack" too much. The position of 3921 // this trace assumes there are fewer obsolete methods than 3922 // EMCP methods. 3923 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) { 3924 ResourceMark rm; 3925 log_trace(redefine, class, obsolete, mark) 3926 ("mark deleted %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string()); 3927 } 3928 } 3929 assert((emcp_method_count + obsolete_count) == _old_methods->length(), 3930 "sanity check"); 3931 log_trace(redefine, class, obsolete, mark)("EMCP_cnt=%d, obsolete_cnt=%d", emcp_method_count, obsolete_count); 3932 return emcp_method_count; 3933 } 3934 3935 // This internal class transfers the native function registration from old methods 3936 // to new methods. It is designed to handle both the simple case of unchanged 3937 // native methods and the complex cases of native method prefixes being added and/or 3938 // removed. 3939 // It expects only to be used during the VM_RedefineClasses op (a safepoint). 3940 // 3941 // This class is used after the new methods have been installed in "the_class". 3942 // 3943 // So, for example, the following must be handled. Where 'm' is a method and 3944 // a number followed by an underscore is a prefix. 3945 // 3946 // Old Name New Name 3947 // Simple transfer to new method m -> m 3948 // Add prefix m -> 1_m 3949 // Remove prefix 1_m -> m 3950 // Simultaneous add of prefixes m -> 3_2_1_m 3951 // Simultaneous removal of prefixes 3_2_1_m -> m 3952 // Simultaneous add and remove 1_m -> 2_m 3953 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m 3954 // 3955 class TransferNativeFunctionRegistration { 3956 private: 3957 InstanceKlass* the_class; 3958 int prefix_count; 3959 char** prefixes; 3960 3961 // Recursively search the binary tree of possibly prefixed method names. 3962 // Iteration could be used if all agents were well behaved. Full tree walk is 3963 // more resilent to agents not cleaning up intermediate methods. 3964 // Branch at each depth in the binary tree is: 3965 // (1) without the prefix. 3966 // (2) with the prefix. 3967 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...) 3968 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len, 3969 Symbol* signature) { 3970 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len); 3971 if (name_symbol != nullptr) { 3972 Method* method = the_class->lookup_method(name_symbol, signature); 3973 if (method != nullptr) { 3974 // Even if prefixed, intermediate methods must exist. 3975 if (method->is_native()) { 3976 // Wahoo, we found a (possibly prefixed) version of the method, return it. 3977 return method; 3978 } 3979 if (depth < prefix_count) { 3980 // Try applying further prefixes (other than this one). 3981 method = search_prefix_name_space(depth+1, name_str, name_len, signature); 3982 if (method != nullptr) { 3983 return method; // found 3984 } 3985 3986 // Try adding this prefix to the method name and see if it matches 3987 // another method name. 3988 char* prefix = prefixes[depth]; 3989 size_t prefix_len = strlen(prefix); 3990 size_t trial_len = name_len + prefix_len; 3991 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1); 3992 strcpy(trial_name_str, prefix); 3993 strcat(trial_name_str, name_str); 3994 method = search_prefix_name_space(depth+1, trial_name_str, trial_len, 3995 signature); 3996 if (method != nullptr) { 3997 // If found along this branch, it was prefixed, mark as such 3998 method->set_is_prefixed_native(); 3999 return method; // found 4000 } 4001 } 4002 } 4003 } 4004 return nullptr; // This whole branch bore nothing 4005 } 4006 4007 // Return the method name with old prefixes stripped away. 4008 char* method_name_without_prefixes(Method* method) { 4009 Symbol* name = method->name(); 4010 char* name_str = name->as_utf8(); 4011 4012 // Old prefixing may be defunct, strip prefixes, if any. 4013 for (int i = prefix_count-1; i >= 0; i--) { 4014 char* prefix = prefixes[i]; 4015 size_t prefix_len = strlen(prefix); 4016 if (strncmp(prefix, name_str, prefix_len) == 0) { 4017 name_str += prefix_len; 4018 } 4019 } 4020 return name_str; 4021 } 4022 4023 // Strip any prefixes off the old native method, then try to find a 4024 // (possibly prefixed) new native that matches it. 4025 Method* strip_and_search_for_new_native(Method* method) { 4026 ResourceMark rm; 4027 char* name_str = method_name_without_prefixes(method); 4028 return search_prefix_name_space(0, name_str, strlen(name_str), 4029 method->signature()); 4030 } 4031 4032 public: 4033 4034 // Construct a native method transfer processor for this class. 4035 TransferNativeFunctionRegistration(InstanceKlass* _the_class) { 4036 assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); 4037 4038 the_class = _the_class; 4039 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count); 4040 } 4041 4042 // Attempt to transfer any of the old or deleted methods that are native 4043 void transfer_registrations(Method** old_methods, int methods_length) { 4044 for (int j = 0; j < methods_length; j++) { 4045 Method* old_method = old_methods[j]; 4046 4047 if (old_method->is_native() && old_method->has_native_function()) { 4048 Method* new_method = strip_and_search_for_new_native(old_method); 4049 if (new_method != nullptr) { 4050 // Actually set the native function in the new method. 4051 // Redefine does not send events (except CFLH), certainly not this 4052 // behind the scenes re-registration. 4053 new_method->set_native_function(old_method->native_function(), 4054 !Method::native_bind_event_is_interesting); 4055 } 4056 } 4057 } 4058 } 4059 }; 4060 4061 // Don't lose the association between a native method and its JNI function. 4062 void VM_RedefineClasses::transfer_old_native_function_registrations(InstanceKlass* the_class) { 4063 TransferNativeFunctionRegistration transfer(the_class); 4064 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length); 4065 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length); 4066 } 4067 4068 // Deoptimize all compiled code that depends on the classes redefined. 4069 // 4070 // If the can_redefine_classes capability is obtained in the onload 4071 // phase or 'AlwaysRecordEvolDependencies' is true, then the compiler has 4072 // recorded all dependencies from startup. In that case we need only 4073 // deoptimize and throw away all compiled code that depends on the class. 4074 // 4075 // If can_redefine_classes is obtained sometime after the onload phase 4076 // (and 'AlwaysRecordEvolDependencies' is false) then the dependency 4077 // information may be incomplete. In that case the first call to 4078 // RedefineClasses causes all compiled code to be thrown away. As 4079 // can_redefine_classes has been obtained then all future compilations will 4080 // record dependencies so second and subsequent calls to RedefineClasses 4081 // need only throw away code that depends on the class. 4082 // 4083 4084 void VM_RedefineClasses::flush_dependent_code() { 4085 assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); 4086 assert(JvmtiExport::all_dependencies_are_recorded() || !AlwaysRecordEvolDependencies, "sanity check"); 4087 4088 DeoptimizationScope deopt_scope; 4089 4090 // This is the first redefinition, mark all the nmethods for deoptimization 4091 if (!JvmtiExport::all_dependencies_are_recorded()) { 4092 CodeCache::mark_all_nmethods_for_evol_deoptimization(&deopt_scope); 4093 log_debug(redefine, class, nmethod)("Marked all nmethods for deopt"); 4094 } else { 4095 CodeCache::mark_dependents_for_evol_deoptimization(&deopt_scope); 4096 log_debug(redefine, class, nmethod)("Marked dependent nmethods for deopt"); 4097 } 4098 4099 deopt_scope.deoptimize_marked(); 4100 4101 // From now on we know that the dependency information is complete 4102 JvmtiExport::set_all_dependencies_are_recorded(true); 4103 } 4104 4105 void VM_RedefineClasses::compute_added_deleted_matching_methods() { 4106 Method* old_method; 4107 Method* new_method; 4108 4109 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 4110 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 4111 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length()); 4112 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 4113 4114 _matching_methods_length = 0; 4115 _deleted_methods_length = 0; 4116 _added_methods_length = 0; 4117 4118 int nj = 0; 4119 int oj = 0; 4120 while (true) { 4121 if (oj >= _old_methods->length()) { 4122 if (nj >= _new_methods->length()) { 4123 break; // we've looked at everything, done 4124 } 4125 // New method at the end 4126 new_method = _new_methods->at(nj); 4127 _added_methods[_added_methods_length++] = new_method; 4128 ++nj; 4129 } else if (nj >= _new_methods->length()) { 4130 // Old method, at the end, is deleted 4131 old_method = _old_methods->at(oj); 4132 _deleted_methods[_deleted_methods_length++] = old_method; 4133 ++oj; 4134 } else { 4135 old_method = _old_methods->at(oj); 4136 new_method = _new_methods->at(nj); 4137 if (old_method->name() == new_method->name()) { 4138 if (old_method->signature() == new_method->signature()) { 4139 _matching_old_methods[_matching_methods_length ] = old_method; 4140 _matching_new_methods[_matching_methods_length++] = new_method; 4141 ++nj; 4142 ++oj; 4143 } else { 4144 // added overloaded have already been moved to the end, 4145 // so this is a deleted overloaded method 4146 _deleted_methods[_deleted_methods_length++] = old_method; 4147 ++oj; 4148 } 4149 } else { // names don't match 4150 if (old_method->name()->fast_compare(new_method->name()) > 0) { 4151 // new method 4152 _added_methods[_added_methods_length++] = new_method; 4153 ++nj; 4154 } else { 4155 // deleted method 4156 _deleted_methods[_deleted_methods_length++] = old_method; 4157 ++oj; 4158 } 4159 } 4160 } 4161 } 4162 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity"); 4163 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity"); 4164 } 4165 4166 4167 void VM_RedefineClasses::swap_annotations(InstanceKlass* the_class, 4168 InstanceKlass* scratch_class) { 4169 // Swap annotation fields values 4170 Annotations* old_annotations = the_class->annotations(); 4171 the_class->set_annotations(scratch_class->annotations()); 4172 scratch_class->set_annotations(old_annotations); 4173 } 4174 4175 4176 // Install the redefinition of a class: 4177 // - house keeping (flushing breakpoints and caches, deoptimizing 4178 // dependent compiled code) 4179 // - replacing parts in the_class with parts from scratch_class 4180 // - adding a weak reference to track the obsolete but interesting 4181 // parts of the_class 4182 // - adjusting constant pool caches and vtables in other classes 4183 // that refer to methods in the_class. These adjustments use the 4184 // ClassLoaderDataGraph::classes_do() facility which only allows 4185 // a helper method to be specified. The interesting parameters 4186 // that we would like to pass to the helper method are saved in 4187 // static global fields in the VM operation. 4188 void VM_RedefineClasses::redefine_single_class(Thread* current, jclass the_jclass, 4189 InstanceKlass* scratch_class) { 4190 4191 HandleMark hm(current); // make sure handles from this call are freed 4192 4193 if (log_is_enabled(Info, redefine, class, timer)) { 4194 _timer_rsc_phase1.start(); 4195 } 4196 4197 InstanceKlass* the_class = get_ik(the_jclass); 4198 4199 // Set a flag to control and optimize adjusting method entries 4200 _has_redefined_Object |= the_class == vmClasses::Object_klass(); 4201 4202 // Remove all breakpoints in methods of this class 4203 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints(); 4204 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class); 4205 4206 _old_methods = the_class->methods(); 4207 _new_methods = scratch_class->methods(); 4208 _the_class = the_class; 4209 compute_added_deleted_matching_methods(); 4210 update_jmethod_ids(); 4211 4212 _any_class_has_resolved_methods = the_class->has_resolved_methods() || _any_class_has_resolved_methods; 4213 4214 // Attach new constant pool to the original klass. The original 4215 // klass still refers to the old constant pool (for now). 4216 scratch_class->constants()->set_pool_holder(the_class); 4217 4218 #if 0 4219 // In theory, with constant pool merging in place we should be able 4220 // to save space by using the new, merged constant pool in place of 4221 // the old constant pool(s). By "pool(s)" I mean the constant pool in 4222 // the klass version we are replacing now and any constant pool(s) in 4223 // previous versions of klass. Nice theory, doesn't work in practice. 4224 // When this code is enabled, even simple programs throw NullPointer 4225 // exceptions. I'm guessing that this is caused by some constant pool 4226 // cache difference between the new, merged constant pool and the 4227 // constant pool that was just being used by the klass. I'm keeping 4228 // this code around to archive the idea, but the code has to remain 4229 // disabled for now. 4230 4231 // Attach each old method to the new constant pool. This can be 4232 // done here since we are past the bytecode verification and 4233 // constant pool optimization phases. 4234 for (int i = _old_methods->length() - 1; i >= 0; i--) { 4235 Method* method = _old_methods->at(i); 4236 method->set_constants(scratch_class->constants()); 4237 } 4238 4239 // NOTE: this doesn't work because you can redefine the same class in two 4240 // threads, each getting their own constant pool data appended to the 4241 // original constant pool. In order for the new methods to work when they 4242 // become old methods, they need to keep their updated copy of the constant pool. 4243 4244 { 4245 // walk all previous versions of the klass 4246 InstanceKlass *ik = the_class; 4247 PreviousVersionWalker pvw(ik); 4248 do { 4249 ik = pvw.next_previous_version(); 4250 if (ik != nullptr) { 4251 4252 // attach previous version of klass to the new constant pool 4253 ik->set_constants(scratch_class->constants()); 4254 4255 // Attach each method in the previous version of klass to the 4256 // new constant pool 4257 Array<Method*>* prev_methods = ik->methods(); 4258 for (int i = prev_methods->length() - 1; i >= 0; i--) { 4259 Method* method = prev_methods->at(i); 4260 method->set_constants(scratch_class->constants()); 4261 } 4262 } 4263 } while (ik != nullptr); 4264 } 4265 #endif 4266 4267 // Replace methods and constantpool 4268 the_class->set_methods(_new_methods); 4269 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods, 4270 // and to be able to undo operation easily. 4271 4272 Array<int>* old_ordering = the_class->method_ordering(); 4273 the_class->set_method_ordering(scratch_class->method_ordering()); 4274 scratch_class->set_method_ordering(old_ordering); 4275 4276 ConstantPool* old_constants = the_class->constants(); 4277 the_class->set_constants(scratch_class->constants()); 4278 scratch_class->set_constants(old_constants); // See the previous comment. 4279 #if 0 4280 // We are swapping the guts of "the new class" with the guts of "the 4281 // class". Since the old constant pool has just been attached to "the 4282 // new class", it seems logical to set the pool holder in the old 4283 // constant pool also. However, doing this will change the observable 4284 // class hierarchy for any old methods that are still executing. A 4285 // method can query the identity of its "holder" and this query uses 4286 // the method's constant pool link to find the holder. The change in 4287 // holding class from "the class" to "the new class" can confuse 4288 // things. 4289 // 4290 // Setting the old constant pool's holder will also cause 4291 // verification done during vtable initialization below to fail. 4292 // During vtable initialization, the vtable's class is verified to be 4293 // a subtype of the method's holder. The vtable's class is "the 4294 // class" and the method's holder is gotten from the constant pool 4295 // link in the method itself. For "the class"'s directly implemented 4296 // methods, the method holder is "the class" itself (as gotten from 4297 // the new constant pool). The check works fine in this case. The 4298 // check also works fine for methods inherited from super classes. 4299 // 4300 // Miranda methods are a little more complicated. A miranda method is 4301 // provided by an interface when the class implementing the interface 4302 // does not provide its own method. These interfaces are implemented 4303 // internally as an InstanceKlass. These special instanceKlasses 4304 // share the constant pool of the class that "implements" the 4305 // interface. By sharing the constant pool, the method holder of a 4306 // miranda method is the class that "implements" the interface. In a 4307 // non-redefine situation, the subtype check works fine. However, if 4308 // the old constant pool's pool holder is modified, then the check 4309 // fails because there is no class hierarchy relationship between the 4310 // vtable's class and "the new class". 4311 4312 old_constants->set_pool_holder(scratch_class()); 4313 #endif 4314 4315 // track number of methods that are EMCP for add_previous_version() call below 4316 int emcp_method_count = check_methods_and_mark_as_obsolete(); 4317 transfer_old_native_function_registrations(the_class); 4318 4319 if (scratch_class->get_cached_class_file() != the_class->get_cached_class_file()) { 4320 // 1. the_class doesn't have a cache yet, scratch_class does have a cache. 4321 // 2. The same class can be present twice in the scratch classes list or there 4322 // are multiple concurrent RetransformClasses calls on different threads. 4323 // the_class and scratch_class have the same cached bytes, but different buffers. 4324 // In such cases we need to deallocate one of the buffers. 4325 // 3. RedefineClasses and the_class has cached bytes from a previous transformation. 4326 // In the case we need to use class bytes from scratch_class. 4327 if (the_class->get_cached_class_file() != nullptr) { 4328 os::free(the_class->get_cached_class_file()); 4329 } 4330 the_class->set_cached_class_file(scratch_class->get_cached_class_file()); 4331 } 4332 4333 // null out in scratch class to not delete twice. The class to be redefined 4334 // always owns these bytes. 4335 scratch_class->set_cached_class_file(nullptr); 4336 4337 // Replace inner_classes 4338 Array<u2>* old_inner_classes = the_class->inner_classes(); 4339 the_class->set_inner_classes(scratch_class->inner_classes()); 4340 scratch_class->set_inner_classes(old_inner_classes); 4341 4342 // Initialize the vtable and interface table after 4343 // methods have been rewritten 4344 // no exception should happen here since we explicitly 4345 // do not check loader constraints. 4346 // compare_and_normalize_class_versions has already checked: 4347 // - classloaders unchanged, signatures unchanged 4348 // - all instanceKlasses for redefined classes reused & contents updated 4349 the_class->vtable().initialize_vtable(); 4350 the_class->itable().initialize_itable(); 4351 4352 // Update jmethodID cache if present. 4353 the_class->update_methods_jmethod_cache(); 4354 4355 // Copy the "source debug extension" attribute from new class version 4356 the_class->set_source_debug_extension( 4357 scratch_class->source_debug_extension(), 4358 scratch_class->source_debug_extension() == nullptr ? 0 : 4359 (int)strlen(scratch_class->source_debug_extension())); 4360 4361 // Use of javac -g could be different in the old and the new 4362 if (scratch_class->has_localvariable_table() != 4363 the_class->has_localvariable_table()) { 4364 the_class->set_has_localvariable_table(scratch_class->has_localvariable_table()); 4365 } 4366 4367 swap_annotations(the_class, scratch_class); 4368 4369 // Replace minor version number of class file 4370 u2 old_minor_version = the_class->constants()->minor_version(); 4371 the_class->constants()->set_minor_version(scratch_class->constants()->minor_version()); 4372 scratch_class->constants()->set_minor_version(old_minor_version); 4373 4374 // Replace major version number of class file 4375 u2 old_major_version = the_class->constants()->major_version(); 4376 the_class->constants()->set_major_version(scratch_class->constants()->major_version()); 4377 scratch_class->constants()->set_major_version(old_major_version); 4378 4379 // Replace CP indexes for class and name+type of enclosing method 4380 u2 old_class_idx = the_class->enclosing_method_class_index(); 4381 u2 old_method_idx = the_class->enclosing_method_method_index(); 4382 the_class->set_enclosing_method_indices( 4383 scratch_class->enclosing_method_class_index(), 4384 scratch_class->enclosing_method_method_index()); 4385 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx); 4386 4387 if (!the_class->has_been_redefined()) { 4388 the_class->set_has_been_redefined(); 4389 } 4390 4391 // Scratch class is unloaded but still needs cleaning, and skipping for CDS. 4392 scratch_class->set_is_scratch_class(); 4393 4394 // keep track of previous versions of this class 4395 the_class->add_previous_version(scratch_class, emcp_method_count); 4396 4397 _timer_rsc_phase1.stop(); 4398 if (log_is_enabled(Info, redefine, class, timer)) { 4399 _timer_rsc_phase2.start(); 4400 } 4401 4402 if (the_class->oop_map_cache() != nullptr) { 4403 // Flush references to any obsolete methods from the oop map cache 4404 // so that obsolete methods are not pinned. 4405 the_class->oop_map_cache()->flush_obsolete_entries(); 4406 } 4407 4408 increment_class_counter(the_class); 4409 4410 if (EventClassRedefinition::is_enabled()) { 4411 EventClassRedefinition event; 4412 event.set_classModificationCount(java_lang_Class::classRedefinedCount(the_class->java_mirror())); 4413 event.set_redefinedClass(the_class); 4414 event.set_redefinitionId(_id); 4415 event.commit(); 4416 } 4417 4418 { 4419 ResourceMark rm(current); 4420 // increment the classRedefinedCount field in the_class and in any 4421 // direct and indirect subclasses of the_class 4422 log_info(redefine, class, load) 4423 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)", 4424 the_class->external_name(), java_lang_Class::classRedefinedCount(the_class->java_mirror()), os::available_memory() >> 10); 4425 Events::log_redefinition(current, "redefined class name=%s, count=%d", 4426 the_class->external_name(), 4427 java_lang_Class::classRedefinedCount(the_class->java_mirror())); 4428 4429 } 4430 _timer_rsc_phase2.stop(); 4431 4432 } // end redefine_single_class() 4433 4434 4435 // Increment the classRedefinedCount field in the specific InstanceKlass 4436 // and in all direct and indirect subclasses. 4437 void VM_RedefineClasses::increment_class_counter(InstanceKlass* ik) { 4438 for (ClassHierarchyIterator iter(ik); !iter.done(); iter.next()) { 4439 // Only update instanceKlasses 4440 Klass* sub = iter.klass(); 4441 if (sub->is_instance_klass()) { 4442 oop class_mirror = InstanceKlass::cast(sub)->java_mirror(); 4443 Klass* class_oop = java_lang_Class::as_Klass(class_mirror); 4444 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1; 4445 java_lang_Class::set_classRedefinedCount(class_mirror, new_count); 4446 4447 if (class_oop != _the_class) { 4448 // _the_class count is printed at end of redefine_single_class() 4449 log_debug(redefine, class, subclass)("updated count in subclass=%s to %d", ik->external_name(), new_count); 4450 } 4451 } 4452 } 4453 } 4454 4455 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) { 4456 bool no_old_methods = true; // be optimistic 4457 4458 // Both array and instance classes have vtables. 4459 // a vtable should never contain old or obsolete methods 4460 ResourceMark rm(_thread); 4461 if (k->vtable_length() > 0 && 4462 !k->vtable().check_no_old_or_obsolete_entries()) { 4463 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 4464 log_trace(redefine, class, obsolete, metadata) 4465 ("klassVtable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s", 4466 k->signature_name()); 4467 k->vtable().dump_vtable(); 4468 } 4469 no_old_methods = false; 4470 } 4471 4472 if (k->is_instance_klass()) { 4473 HandleMark hm(_thread); 4474 InstanceKlass *ik = InstanceKlass::cast(k); 4475 4476 // an itable should never contain old or obsolete methods 4477 if (ik->itable_length() > 0 && 4478 !ik->itable().check_no_old_or_obsolete_entries()) { 4479 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 4480 log_trace(redefine, class, obsolete, metadata) 4481 ("klassItable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s", 4482 ik->signature_name()); 4483 ik->itable().dump_itable(); 4484 } 4485 no_old_methods = false; 4486 } 4487 4488 // the constant pool cache should never contain non-deleted old or obsolete methods 4489 if (ik->constants() != nullptr && 4490 ik->constants()->cache() != nullptr && 4491 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) { 4492 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 4493 log_trace(redefine, class, obsolete, metadata) 4494 ("cp-cache::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s", 4495 ik->signature_name()); 4496 ik->constants()->cache()->dump_cache(); 4497 } 4498 no_old_methods = false; 4499 } 4500 } 4501 4502 // print and fail guarantee if old methods are found. 4503 if (!no_old_methods) { 4504 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 4505 dump_methods(); 4506 } else { 4507 log_trace(redefine, class)("Use the '-Xlog:redefine+class*:' option " 4508 "to see more info about the following guarantee() failure."); 4509 } 4510 guarantee(false, "OLD and/or OBSOLETE method(s) found"); 4511 } 4512 } 4513 4514 u8 VM_RedefineClasses::next_id() { 4515 while (true) { 4516 u8 id = _id_counter; 4517 u8 next_id = id + 1; 4518 u8 result = Atomic::cmpxchg(&_id_counter, id, next_id); 4519 if (result == id) { 4520 return next_id; 4521 } 4522 } 4523 } 4524 4525 void VM_RedefineClasses::dump_methods() { 4526 int j; 4527 log_trace(redefine, class, dump)("_old_methods --"); 4528 for (j = 0; j < _old_methods->length(); ++j) { 4529 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4530 Method* m = _old_methods->at(j); 4531 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4532 m->access_flags().print_on(&log_stream); 4533 log_stream.print(" -- "); 4534 m->print_name(&log_stream); 4535 log_stream.cr(); 4536 } 4537 log_trace(redefine, class, dump)("_new_methods --"); 4538 for (j = 0; j < _new_methods->length(); ++j) { 4539 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4540 Method* m = _new_methods->at(j); 4541 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4542 m->access_flags().print_on(&log_stream); 4543 log_stream.print(" -- "); 4544 m->print_name(&log_stream); 4545 log_stream.cr(); 4546 } 4547 log_trace(redefine, class, dump)("_matching_methods --"); 4548 for (j = 0; j < _matching_methods_length; ++j) { 4549 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4550 Method* m = _matching_old_methods[j]; 4551 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4552 m->access_flags().print_on(&log_stream); 4553 log_stream.print(" -- "); 4554 m->print_name(); 4555 log_stream.cr(); 4556 4557 m = _matching_new_methods[j]; 4558 log_stream.print(" (%5d) ", m->vtable_index()); 4559 m->access_flags().print_on(&log_stream); 4560 log_stream.cr(); 4561 } 4562 log_trace(redefine, class, dump)("_deleted_methods --"); 4563 for (j = 0; j < _deleted_methods_length; ++j) { 4564 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4565 Method* m = _deleted_methods[j]; 4566 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4567 m->access_flags().print_on(&log_stream); 4568 log_stream.print(" -- "); 4569 m->print_name(&log_stream); 4570 log_stream.cr(); 4571 } 4572 log_trace(redefine, class, dump)("_added_methods --"); 4573 for (j = 0; j < _added_methods_length; ++j) { 4574 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4575 Method* m = _added_methods[j]; 4576 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4577 m->access_flags().print_on(&log_stream); 4578 log_stream.print(" -- "); 4579 m->print_name(&log_stream); 4580 log_stream.cr(); 4581 } 4582 } 4583 4584 void VM_RedefineClasses::print_on_error(outputStream* st) const { 4585 VM_Operation::print_on_error(st); 4586 if (_the_class != nullptr) { 4587 ResourceMark rm; 4588 st->print_cr(", redefining class %s", _the_class->external_name()); 4589 } 4590 }