1 /* 2 * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "cds/metaspaceShared.hpp" 27 #include "classfile/classFileStream.hpp" 28 #include "classfile/classLoaderDataGraph.hpp" 29 #include "classfile/classLoadInfo.hpp" 30 #include "classfile/javaClasses.inline.hpp" 31 #include "classfile/metadataOnStackMark.hpp" 32 #include "classfile/symbolTable.hpp" 33 #include "classfile/klassFactory.hpp" 34 #include "classfile/verifier.hpp" 35 #include "classfile/vmClasses.hpp" 36 #include "classfile/vmSymbols.hpp" 37 #include "code/codeCache.hpp" 38 #include "compiler/compileBroker.hpp" 39 #include "interpreter/oopMapCache.hpp" 40 #include "interpreter/rewriter.hpp" 41 #include "jfr/jfrEvents.hpp" 42 #include "logging/logStream.hpp" 43 #include "memory/metadataFactory.hpp" 44 #include "memory/resourceArea.hpp" 45 #include "memory/universe.hpp" 46 #include "oops/annotations.hpp" 47 #include "oops/constantPool.hpp" 48 #include "oops/fieldStreams.inline.hpp" 49 #include "oops/klass.inline.hpp" 50 #include "oops/klassVtable.hpp" 51 #include "oops/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 (UseSharedSpaces) { 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 jushort old_flags = (jushort) the_class->access_flags().get_flags(); 1008 jushort new_flags = (jushort) scratch_class->access_flags().get_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_short(); 1043 new_flags = new_fs.access_flags().as_short(); 1044 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) { 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 = (jushort) k_old_method->access_flags().get_flags(); 1150 new_flags = (jushort) k_new_method->access_flags().get_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_addr());) 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 ClassFileStream::verify); 1366 1367 // Set redefined class handle in JvmtiThreadState class. 1368 // This redefined class is sent to agent event handler for class file 1369 // load hook event. 1370 state->set_class_being_redefined(the_class, _class_load_kind); 1371 1372 JavaThread* THREAD = current; // For exception macros. 1373 ExceptionMark em(THREAD); 1374 Handle protection_domain(THREAD, the_class->protection_domain()); 1375 ClassLoadInfo cl_info(protection_domain); 1376 // Parse and create a class from the bytes, but this class isn't added 1377 // to the dictionary, so do not call resolve_from_stream. 1378 InstanceKlass* scratch_class = KlassFactory::create_from_stream(&st, 1379 the_class->name(), 1380 the_class->class_loader_data(), 1381 cl_info, 1382 THREAD); 1383 1384 // Clear class_being_redefined just to be sure. 1385 state->clear_class_being_redefined(); 1386 1387 // TODO: if this is retransform, and nothing changed we can skip it 1388 1389 // Need to clean up allocated InstanceKlass if there's an error so assign 1390 // the result here. Caller deallocates all the scratch classes in case of 1391 // an error. 1392 _scratch_classes[i] = scratch_class; 1393 1394 if (HAS_PENDING_EXCEPTION) { 1395 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1396 log_info(redefine, class, load, exceptions)("create_from_stream exception: '%s'", ex_name->as_C_string()); 1397 CLEAR_PENDING_EXCEPTION; 1398 1399 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) { 1400 return JVMTI_ERROR_UNSUPPORTED_VERSION; 1401 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) { 1402 return JVMTI_ERROR_INVALID_CLASS_FORMAT; 1403 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) { 1404 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION; 1405 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) { 1406 // The message will be "XXX (wrong name: YYY)" 1407 return JVMTI_ERROR_NAMES_DONT_MATCH; 1408 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1409 return JVMTI_ERROR_OUT_OF_MEMORY; 1410 } else { // Just in case more exceptions can be thrown.. 1411 return JVMTI_ERROR_FAILS_VERIFICATION; 1412 } 1413 } 1414 1415 // Ensure class is linked before redefine 1416 if (!the_class->is_linked()) { 1417 the_class->link_class(THREAD); 1418 if (HAS_PENDING_EXCEPTION) { 1419 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1420 oop message = java_lang_Throwable::message(PENDING_EXCEPTION); 1421 if (message != nullptr) { 1422 char* ex_msg = java_lang_String::as_utf8_string(message); 1423 log_info(redefine, class, load, exceptions)("link_class exception: '%s %s'", 1424 ex_name->as_C_string(), ex_msg); 1425 } else { 1426 log_info(redefine, class, load, exceptions)("link_class exception: '%s'", 1427 ex_name->as_C_string()); 1428 } 1429 CLEAR_PENDING_EXCEPTION; 1430 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1431 return JVMTI_ERROR_OUT_OF_MEMORY; 1432 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) { 1433 return JVMTI_ERROR_INVALID_CLASS; 1434 } else { 1435 return JVMTI_ERROR_INTERNAL; 1436 } 1437 } 1438 } 1439 1440 // Do the validity checks in compare_and_normalize_class_versions() 1441 // before verifying the byte codes. By doing these checks first, we 1442 // limit the number of functions that require redirection from 1443 // the_class to scratch_class. In particular, we don't have to 1444 // modify JNI GetSuperclass() and thus won't change its performance. 1445 jvmtiError res = compare_and_normalize_class_versions(the_class, 1446 scratch_class); 1447 if (res != JVMTI_ERROR_NONE) { 1448 return res; 1449 } 1450 1451 // verify what the caller passed us 1452 { 1453 // The bug 6214132 caused the verification to fail. 1454 // Information about the_class and scratch_class is temporarily 1455 // recorded into jvmtiThreadState. This data is used to redirect 1456 // the_class to scratch_class in the JVM_* functions called by the 1457 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed 1458 // description. 1459 RedefineVerifyMark rvm(the_class, scratch_class, state); 1460 Verifier::verify(scratch_class, true, THREAD); 1461 } 1462 1463 if (HAS_PENDING_EXCEPTION) { 1464 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1465 log_info(redefine, class, load, exceptions)("verify_byte_codes exception: '%s'", ex_name->as_C_string()); 1466 CLEAR_PENDING_EXCEPTION; 1467 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1468 return JVMTI_ERROR_OUT_OF_MEMORY; 1469 } else { 1470 // tell the caller the bytecodes are bad 1471 return JVMTI_ERROR_FAILS_VERIFICATION; 1472 } 1473 } 1474 1475 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD); 1476 if (HAS_PENDING_EXCEPTION) { 1477 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1478 log_info(redefine, class, load, exceptions)("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string()); 1479 CLEAR_PENDING_EXCEPTION; 1480 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1481 return JVMTI_ERROR_OUT_OF_MEMORY; 1482 } else { 1483 return JVMTI_ERROR_INTERNAL; 1484 } 1485 } 1486 1487 #ifdef ASSERT 1488 { 1489 // verify what we have done during constant pool merging 1490 { 1491 RedefineVerifyMark rvm(the_class, scratch_class, state); 1492 Verifier::verify(scratch_class, true, THREAD); 1493 } 1494 1495 if (HAS_PENDING_EXCEPTION) { 1496 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1497 log_info(redefine, class, load, exceptions) 1498 ("verify_byte_codes post merge-CP exception: '%s'", ex_name->as_C_string()); 1499 CLEAR_PENDING_EXCEPTION; 1500 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1501 return JVMTI_ERROR_OUT_OF_MEMORY; 1502 } else { 1503 // tell the caller that constant pool merging screwed up 1504 return JVMTI_ERROR_INTERNAL; 1505 } 1506 } 1507 } 1508 #endif // ASSERT 1509 1510 Rewriter::rewrite(scratch_class, THREAD); 1511 if (!HAS_PENDING_EXCEPTION) { 1512 scratch_class->link_methods(THREAD); 1513 } 1514 if (HAS_PENDING_EXCEPTION) { 1515 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1516 log_info(redefine, class, load, exceptions) 1517 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string()); 1518 CLEAR_PENDING_EXCEPTION; 1519 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1520 return JVMTI_ERROR_OUT_OF_MEMORY; 1521 } else { 1522 return JVMTI_ERROR_INTERNAL; 1523 } 1524 } 1525 1526 log_debug(redefine, class, load) 1527 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)", the_class->external_name(), os::available_memory() >> 10); 1528 } 1529 1530 return JVMTI_ERROR_NONE; 1531 } 1532 1533 1534 // Map old_index to new_index as needed. scratch_cp is only needed 1535 // for log calls. 1536 void VM_RedefineClasses::map_index(const constantPoolHandle& scratch_cp, 1537 int old_index, int new_index) { 1538 if (find_new_index(old_index) != 0) { 1539 // old_index is already mapped 1540 return; 1541 } 1542 1543 if (old_index == new_index) { 1544 // no mapping is needed 1545 return; 1546 } 1547 1548 _index_map_p->at_put(old_index, new_index); 1549 _index_map_count++; 1550 1551 log_trace(redefine, class, constantpool) 1552 ("mapped tag %d at index %d to %d", scratch_cp->tag_at(old_index).value(), old_index, new_index); 1553 } // end map_index() 1554 1555 1556 // Map old_index to new_index as needed. 1557 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) { 1558 if (find_new_operand_index(old_index) != -1) { 1559 // old_index is already mapped 1560 return; 1561 } 1562 1563 if (old_index == new_index) { 1564 // no mapping is needed 1565 return; 1566 } 1567 1568 _operands_index_map_p->at_put(old_index, new_index); 1569 _operands_index_map_count++; 1570 1571 log_trace(redefine, class, constantpool)("mapped bootstrap specifier at index %d to %d", old_index, new_index); 1572 } // end map_index() 1573 1574 1575 // Merge old_cp and scratch_cp and return the results of the merge via 1576 // merge_cp_p. The number of entries in *merge_cp_p is returned via 1577 // merge_cp_length_p. The entries in old_cp occupy the same locations 1578 // in *merge_cp_p. Also creates a map of indices from entries in 1579 // scratch_cp to the corresponding entry in *merge_cp_p. Index map 1580 // entries are only created for entries in scratch_cp that occupy a 1581 // different location in *merged_cp_p. 1582 bool VM_RedefineClasses::merge_constant_pools(const constantPoolHandle& old_cp, 1583 const constantPoolHandle& scratch_cp, constantPoolHandle *merge_cp_p, 1584 int *merge_cp_length_p, TRAPS) { 1585 1586 if (merge_cp_p == nullptr) { 1587 assert(false, "caller must provide scratch constantPool"); 1588 return false; // robustness 1589 } 1590 if (merge_cp_length_p == nullptr) { 1591 assert(false, "caller must provide scratch CP length"); 1592 return false; // robustness 1593 } 1594 // Worst case we need old_cp->length() + scratch_cp()->length(), 1595 // but the caller might be smart so make sure we have at least 1596 // the minimum. 1597 if ((*merge_cp_p)->length() < old_cp->length()) { 1598 assert(false, "merge area too small"); 1599 return false; // robustness 1600 } 1601 1602 log_info(redefine, class, constantpool)("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(), scratch_cp->length()); 1603 1604 { 1605 // Pass 0: 1606 // The old_cp is copied to *merge_cp_p; this means that any code 1607 // using old_cp does not have to change. This work looks like a 1608 // perfect fit for ConstantPool*::copy_cp_to(), but we need to 1609 // handle one special case: 1610 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass 1611 // This will make verification happy. 1612 1613 int old_i; // index into old_cp 1614 1615 // index zero (0) is not used in constantPools 1616 for (old_i = 1; old_i < old_cp->length(); old_i++) { 1617 // leave debugging crumb 1618 jbyte old_tag = old_cp->tag_at(old_i).value(); 1619 switch (old_tag) { 1620 case JVM_CONSTANT_Class: 1621 case JVM_CONSTANT_UnresolvedClass: 1622 // revert the copy to JVM_CONSTANT_UnresolvedClass 1623 // May be resolving while calling this so do the same for 1624 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition) 1625 (*merge_cp_p)->temp_unresolved_klass_at_put(old_i, 1626 old_cp->klass_name_index_at(old_i)); 1627 break; 1628 1629 case JVM_CONSTANT_Double: 1630 case JVM_CONSTANT_Long: 1631 // just copy the entry to *merge_cp_p, but double and long take 1632 // two constant pool entries 1633 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i); 1634 old_i++; 1635 break; 1636 1637 default: 1638 // just copy the entry to *merge_cp_p 1639 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i); 1640 break; 1641 } 1642 } // end for each old_cp entry 1643 1644 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_false); 1645 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_false); 1646 1647 // We don't need to sanity check that *merge_cp_length_p is within 1648 // *merge_cp_p bounds since we have the minimum on-entry check above. 1649 (*merge_cp_length_p) = old_i; 1650 } 1651 1652 // merge_cp_len should be the same as old_cp->length() at this point 1653 // so this trace message is really a "warm-and-breathing" message. 1654 log_debug(redefine, class, constantpool)("after pass 0: merge_cp_len=%d", *merge_cp_length_p); 1655 1656 int scratch_i; // index into scratch_cp 1657 { 1658 // Pass 1a: 1659 // Compare scratch_cp entries to the old_cp entries that we have 1660 // already copied to *merge_cp_p. In this pass, we are eliminating 1661 // exact duplicates (matching entry at same index) so we only 1662 // compare entries in the common indice range. 1663 int increment = 1; 1664 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length()); 1665 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) { 1666 switch (scratch_cp->tag_at(scratch_i).value()) { 1667 case JVM_CONSTANT_Double: 1668 case JVM_CONSTANT_Long: 1669 // double and long take two constant pool entries 1670 increment = 2; 1671 break; 1672 1673 default: 1674 increment = 1; 1675 break; 1676 } 1677 1678 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p, scratch_i); 1679 if (match) { 1680 // found a match at the same index so nothing more to do 1681 continue; 1682 } 1683 1684 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p); 1685 if (found_i != 0) { 1686 guarantee(found_i != scratch_i, 1687 "compare_entry_to() and find_matching_entry() do not agree"); 1688 1689 // Found a matching entry somewhere else in *merge_cp_p so 1690 // just need a mapping entry. 1691 map_index(scratch_cp, scratch_i, found_i); 1692 continue; 1693 } 1694 1695 // No match found so we have to append this entry and any unique 1696 // referenced entries to *merge_cp_p. 1697 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p); 1698 } 1699 } 1700 1701 log_debug(redefine, class, constantpool) 1702 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", 1703 *merge_cp_length_p, scratch_i, _index_map_count); 1704 1705 if (scratch_i < scratch_cp->length()) { 1706 // Pass 1b: 1707 // old_cp is smaller than scratch_cp so there are entries in 1708 // scratch_cp that we have not yet processed. We take care of 1709 // those now. 1710 int increment = 1; 1711 for (; scratch_i < scratch_cp->length(); scratch_i += increment) { 1712 switch (scratch_cp->tag_at(scratch_i).value()) { 1713 case JVM_CONSTANT_Double: 1714 case JVM_CONSTANT_Long: 1715 // double and long take two constant pool entries 1716 increment = 2; 1717 break; 1718 1719 default: 1720 increment = 1; 1721 break; 1722 } 1723 1724 int found_i = 1725 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p); 1726 if (found_i != 0) { 1727 // Found a matching entry somewhere else in *merge_cp_p so 1728 // just need a mapping entry. 1729 map_index(scratch_cp, scratch_i, found_i); 1730 continue; 1731 } 1732 1733 // No match found so we have to append this entry and any unique 1734 // referenced entries to *merge_cp_p. 1735 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p); 1736 } 1737 1738 log_debug(redefine, class, constantpool) 1739 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", 1740 *merge_cp_length_p, scratch_i, _index_map_count); 1741 } 1742 finalize_operands_merge(*merge_cp_p, CHECK_false); 1743 1744 return true; 1745 } // end merge_constant_pools() 1746 1747 1748 // Scoped object to clean up the constant pool(s) created for merging 1749 class MergeCPCleaner { 1750 ClassLoaderData* _loader_data; 1751 ConstantPool* _cp; 1752 ConstantPool* _scratch_cp; 1753 public: 1754 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) : 1755 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(nullptr) {} 1756 ~MergeCPCleaner() { 1757 _loader_data->add_to_deallocate_list(_cp); 1758 if (_scratch_cp != nullptr) { 1759 _loader_data->add_to_deallocate_list(_scratch_cp); 1760 } 1761 } 1762 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; } 1763 }; 1764 1765 // Merge constant pools between the_class and scratch_class and 1766 // potentially rewrite bytecodes in scratch_class to use the merged 1767 // constant pool. 1768 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite( 1769 InstanceKlass* the_class, InstanceKlass* scratch_class, 1770 TRAPS) { 1771 // worst case merged constant pool length is old and new combined 1772 int merge_cp_length = the_class->constants()->length() 1773 + scratch_class->constants()->length(); 1774 1775 // Constant pools are not easily reused so we allocate a new one 1776 // each time. 1777 // merge_cp is created unsafe for concurrent GC processing. It 1778 // should be marked safe before discarding it. Even though 1779 // garbage, if it crosses a card boundary, it may be scanned 1780 // in order to find the start of the first complete object on the card. 1781 ClassLoaderData* loader_data = the_class->class_loader_data(); 1782 ConstantPool* merge_cp_oop = 1783 ConstantPool::allocate(loader_data, 1784 merge_cp_length, 1785 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1786 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop); 1787 1788 HandleMark hm(THREAD); // make sure handles are cleared before 1789 // MergeCPCleaner clears out merge_cp_oop 1790 constantPoolHandle merge_cp(THREAD, merge_cp_oop); 1791 1792 // Get constants() from the old class because it could have been rewritten 1793 // while we were at a safepoint allocating a new constant pool. 1794 constantPoolHandle old_cp(THREAD, the_class->constants()); 1795 constantPoolHandle scratch_cp(THREAD, scratch_class->constants()); 1796 1797 // If the length changed, the class was redefined out from under us. Return 1798 // an error. 1799 if (merge_cp_length != the_class->constants()->length() 1800 + scratch_class->constants()->length()) { 1801 return JVMTI_ERROR_INTERNAL; 1802 } 1803 1804 // Update the version number of the constant pools (may keep scratch_cp) 1805 merge_cp->increment_and_save_version(old_cp->version()); 1806 scratch_cp->increment_and_save_version(old_cp->version()); 1807 1808 ResourceMark rm(THREAD); 1809 _index_map_count = 0; 1810 _index_map_p = new intArray(scratch_cp->length(), scratch_cp->length(), -1); 1811 1812 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands()); 1813 _operands_index_map_count = 0; 1814 int operands_index_map_len = ConstantPool::operand_array_length(scratch_cp->operands()); 1815 _operands_index_map_p = new intArray(operands_index_map_len, operands_index_map_len, -1); 1816 1817 // reference to the cp holder is needed for copy_operands() 1818 merge_cp->set_pool_holder(scratch_class); 1819 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp, 1820 &merge_cp_length, THREAD); 1821 merge_cp->set_pool_holder(nullptr); 1822 1823 if (!result) { 1824 // The merge can fail due to memory allocation failure or due 1825 // to robustness checks. 1826 return JVMTI_ERROR_INTERNAL; 1827 } 1828 1829 // ensure merged constant pool size does not overflow u2 1830 if (merge_cp_length > 0xFFFF) { 1831 log_warning(redefine, class, constantpool)("Merged constant pool overflow: %d entries", merge_cp_length); 1832 return JVMTI_ERROR_INTERNAL; 1833 } 1834 1835 // Set dynamic constants attribute from the original CP. 1836 if (old_cp->has_dynamic_constant()) { 1837 scratch_cp->set_has_dynamic_constant(); 1838 } 1839 1840 log_info(redefine, class, constantpool)("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count); 1841 1842 if (_index_map_count == 0) { 1843 // there is nothing to map between the new and merged constant pools 1844 1845 // Copy attributes from scratch_cp to merge_cp 1846 merge_cp->copy_fields(scratch_cp()); 1847 1848 if (old_cp->length() == scratch_cp->length()) { 1849 // The old and new constant pools are the same length and the 1850 // index map is empty. This means that the three constant pools 1851 // are equivalent (but not the same). Unfortunately, the new 1852 // constant pool has not gone through link resolution nor have 1853 // the new class bytecodes gone through constant pool cache 1854 // rewriting so we can't use the old constant pool with the new 1855 // class. 1856 1857 // toss the merged constant pool at return 1858 } else if (old_cp->length() < scratch_cp->length()) { 1859 // The old constant pool has fewer entries than the new constant 1860 // pool and the index map is empty. This means the new constant 1861 // pool is a superset of the old constant pool. However, the old 1862 // class bytecodes have already gone through constant pool cache 1863 // rewriting so we can't use the new constant pool with the old 1864 // class. 1865 1866 // toss the merged constant pool at return 1867 } else { 1868 // The old constant pool has more entries than the new constant 1869 // pool and the index map is empty. This means that both the old 1870 // and merged constant pools are supersets of the new constant 1871 // pool. 1872 1873 // Replace the new constant pool with a shrunken copy of the 1874 // merged constant pool 1875 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, 1876 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1877 // The new constant pool replaces scratch_cp so have cleaner clean it up. 1878 // It can't be cleaned up while there are handles to it. 1879 cp_cleaner.add_scratch_cp(scratch_cp()); 1880 } 1881 } else { 1882 if (log_is_enabled(Trace, redefine, class, constantpool)) { 1883 // don't want to loop unless we are tracing 1884 int count = 0; 1885 for (int i = 1; i < _index_map_p->length(); i++) { 1886 int value = _index_map_p->at(i); 1887 1888 if (value != -1) { 1889 log_trace(redefine, class, constantpool)("index_map[%d]: old=%d new=%d", count, i, value); 1890 count++; 1891 } 1892 } 1893 } 1894 1895 // We have entries mapped between the new and merged constant pools 1896 // so we have to rewrite some constant pool references. 1897 if (!rewrite_cp_refs(scratch_class)) { 1898 return JVMTI_ERROR_INTERNAL; 1899 } 1900 1901 // Copy attributes from scratch_cp to merge_cp (should be done after rewrite_cp_refs()) 1902 merge_cp->copy_fields(scratch_cp()); 1903 1904 // Replace the new constant pool with a shrunken copy of the 1905 // merged constant pool so now the rewritten bytecodes have 1906 // valid references; the previous new constant pool will get 1907 // GCed. 1908 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, 1909 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1910 // The new constant pool replaces scratch_cp so have cleaner clean it up. 1911 // It can't be cleaned up while there are handles to it. 1912 cp_cleaner.add_scratch_cp(scratch_cp()); 1913 } 1914 1915 return JVMTI_ERROR_NONE; 1916 } // end merge_cp_and_rewrite() 1917 1918 1919 // Rewrite constant pool references in klass scratch_class. 1920 bool VM_RedefineClasses::rewrite_cp_refs(InstanceKlass* scratch_class) { 1921 1922 // rewrite constant pool references in the nest attributes: 1923 if (!rewrite_cp_refs_in_nest_attributes(scratch_class)) { 1924 // propagate failure back to caller 1925 return false; 1926 } 1927 1928 // rewrite constant pool references in the Record attribute: 1929 if (!rewrite_cp_refs_in_record_attribute(scratch_class)) { 1930 // propagate failure back to caller 1931 return false; 1932 } 1933 1934 // rewrite constant pool references in the PermittedSubclasses attribute: 1935 if (!rewrite_cp_refs_in_permitted_subclasses_attribute(scratch_class)) { 1936 // propagate failure back to caller 1937 return false; 1938 } 1939 1940 // rewrite constant pool references in the methods: 1941 if (!rewrite_cp_refs_in_methods(scratch_class)) { 1942 // propagate failure back to caller 1943 return false; 1944 } 1945 1946 // rewrite constant pool references in the class_annotations: 1947 if (!rewrite_cp_refs_in_class_annotations(scratch_class)) { 1948 // propagate failure back to caller 1949 return false; 1950 } 1951 1952 // rewrite constant pool references in the fields_annotations: 1953 if (!rewrite_cp_refs_in_fields_annotations(scratch_class)) { 1954 // propagate failure back to caller 1955 return false; 1956 } 1957 1958 // rewrite constant pool references in the methods_annotations: 1959 if (!rewrite_cp_refs_in_methods_annotations(scratch_class)) { 1960 // propagate failure back to caller 1961 return false; 1962 } 1963 1964 // rewrite constant pool references in the methods_parameter_annotations: 1965 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class)) { 1966 // propagate failure back to caller 1967 return false; 1968 } 1969 1970 // rewrite constant pool references in the methods_default_annotations: 1971 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class)) { 1972 // propagate failure back to caller 1973 return false; 1974 } 1975 1976 // rewrite constant pool references in the class_type_annotations: 1977 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class)) { 1978 // propagate failure back to caller 1979 return false; 1980 } 1981 1982 // rewrite constant pool references in the fields_type_annotations: 1983 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class)) { 1984 // propagate failure back to caller 1985 return false; 1986 } 1987 1988 // rewrite constant pool references in the methods_type_annotations: 1989 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class)) { 1990 // propagate failure back to caller 1991 return false; 1992 } 1993 1994 // There can be type annotations in the Code part of a method_info attribute. 1995 // These annotations are not accessible, even by reflection. 1996 // Currently they are not even parsed by the ClassFileParser. 1997 // If runtime access is added they will also need to be rewritten. 1998 1999 // rewrite source file name index: 2000 u2 source_file_name_idx = scratch_class->source_file_name_index(); 2001 if (source_file_name_idx != 0) { 2002 u2 new_source_file_name_idx = find_new_index(source_file_name_idx); 2003 if (new_source_file_name_idx != 0) { 2004 scratch_class->set_source_file_name_index(new_source_file_name_idx); 2005 } 2006 } 2007 2008 // rewrite class generic signature index: 2009 u2 generic_signature_index = scratch_class->generic_signature_index(); 2010 if (generic_signature_index != 0) { 2011 u2 new_generic_signature_index = find_new_index(generic_signature_index); 2012 if (new_generic_signature_index != 0) { 2013 scratch_class->set_generic_signature_index(new_generic_signature_index); 2014 } 2015 } 2016 2017 return true; 2018 } // end rewrite_cp_refs() 2019 2020 // Rewrite constant pool references in the NestHost and NestMembers attributes. 2021 bool VM_RedefineClasses::rewrite_cp_refs_in_nest_attributes( 2022 InstanceKlass* scratch_class) { 2023 2024 u2 cp_index = scratch_class->nest_host_index(); 2025 if (cp_index != 0) { 2026 scratch_class->set_nest_host_index(find_new_index(cp_index)); 2027 } 2028 Array<u2>* nest_members = scratch_class->nest_members(); 2029 for (int i = 0; i < nest_members->length(); i++) { 2030 u2 cp_index = nest_members->at(i); 2031 nest_members->at_put(i, find_new_index(cp_index)); 2032 } 2033 return true; 2034 } 2035 2036 // Rewrite constant pool references in the Record attribute. 2037 bool VM_RedefineClasses::rewrite_cp_refs_in_record_attribute(InstanceKlass* scratch_class) { 2038 Array<RecordComponent*>* components = scratch_class->record_components(); 2039 if (components != nullptr) { 2040 for (int i = 0; i < components->length(); i++) { 2041 RecordComponent* component = components->at(i); 2042 u2 cp_index = component->name_index(); 2043 component->set_name_index(find_new_index(cp_index)); 2044 cp_index = component->descriptor_index(); 2045 component->set_descriptor_index(find_new_index(cp_index)); 2046 cp_index = component->generic_signature_index(); 2047 if (cp_index != 0) { 2048 component->set_generic_signature_index(find_new_index(cp_index)); 2049 } 2050 2051 AnnotationArray* annotations = component->annotations(); 2052 if (annotations != nullptr && annotations->length() != 0) { 2053 int byte_i = 0; // byte index into annotations 2054 if (!rewrite_cp_refs_in_annotations_typeArray(annotations, byte_i)) { 2055 log_debug(redefine, class, annotation)("bad record_component_annotations at %d", i); 2056 // propagate failure back to caller 2057 return false; 2058 } 2059 } 2060 2061 AnnotationArray* type_annotations = component->type_annotations(); 2062 if (type_annotations != nullptr && type_annotations->length() != 0) { 2063 int byte_i = 0; // byte index into annotations 2064 if (!rewrite_cp_refs_in_annotations_typeArray(type_annotations, byte_i)) { 2065 log_debug(redefine, class, annotation)("bad record_component_type_annotations at %d", i); 2066 // propagate failure back to caller 2067 return false; 2068 } 2069 } 2070 } 2071 } 2072 return true; 2073 } 2074 2075 // Rewrite constant pool references in the PermittedSubclasses attribute. 2076 bool VM_RedefineClasses::rewrite_cp_refs_in_permitted_subclasses_attribute( 2077 InstanceKlass* scratch_class) { 2078 2079 Array<u2>* permitted_subclasses = scratch_class->permitted_subclasses(); 2080 assert(permitted_subclasses != nullptr, "unexpected null permitted_subclasses"); 2081 for (int i = 0; i < permitted_subclasses->length(); i++) { 2082 u2 cp_index = permitted_subclasses->at(i); 2083 permitted_subclasses->at_put(i, find_new_index(cp_index)); 2084 } 2085 return true; 2086 } 2087 2088 // Rewrite constant pool references in the methods. 2089 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(InstanceKlass* scratch_class) { 2090 2091 Array<Method*>* methods = scratch_class->methods(); 2092 2093 if (methods == nullptr || methods->length() == 0) { 2094 // no methods so nothing to do 2095 return true; 2096 } 2097 2098 JavaThread* THREAD = JavaThread::current(); // For exception macros. 2099 ExceptionMark em(THREAD); 2100 2101 // rewrite constant pool references in the methods: 2102 for (int i = methods->length() - 1; i >= 0; i--) { 2103 methodHandle method(THREAD, methods->at(i)); 2104 methodHandle new_method; 2105 rewrite_cp_refs_in_method(method, &new_method, THREAD); 2106 if (!new_method.is_null()) { 2107 // the method has been replaced so save the new method version 2108 // even in the case of an exception. original method is on the 2109 // deallocation list. 2110 methods->at_put(i, new_method()); 2111 } 2112 if (HAS_PENDING_EXCEPTION) { 2113 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 2114 log_info(redefine, class, load, exceptions)("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string()); 2115 // Need to clear pending exception here as the super caller sets 2116 // the JVMTI_ERROR_INTERNAL if the returned value is false. 2117 CLEAR_PENDING_EXCEPTION; 2118 return false; 2119 } 2120 } 2121 2122 return true; 2123 } 2124 2125 2126 // Rewrite constant pool references in the specific method. This code 2127 // was adapted from Rewriter::rewrite_method(). 2128 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method, 2129 methodHandle *new_method_p, TRAPS) { 2130 2131 *new_method_p = methodHandle(); // default is no new method 2132 2133 // We cache a pointer to the bytecodes here in code_base. If GC 2134 // moves the Method*, then the bytecodes will also move which 2135 // will likely cause a crash. We create a NoSafepointVerifier 2136 // object to detect whether we pass a possible safepoint in this 2137 // code block. 2138 NoSafepointVerifier nsv; 2139 2140 // Bytecodes and their length 2141 address code_base = method->code_base(); 2142 int code_length = method->code_size(); 2143 2144 int bc_length; 2145 for (int bci = 0; bci < code_length; bci += bc_length) { 2146 address bcp = code_base + bci; 2147 Bytecodes::Code c = (Bytecodes::Code)(*bcp); 2148 2149 bc_length = Bytecodes::length_for(c); 2150 if (bc_length == 0) { 2151 // More complicated bytecodes report a length of zero so 2152 // we have to try again a slightly different way. 2153 bc_length = Bytecodes::length_at(method(), bcp); 2154 } 2155 2156 assert(bc_length != 0, "impossible bytecode length"); 2157 2158 switch (c) { 2159 case Bytecodes::_ldc: 2160 { 2161 u1 cp_index = *(bcp + 1); 2162 u2 new_index = find_new_index(cp_index); 2163 2164 if (StressLdcRewrite && new_index == 0) { 2165 // If we are stressing ldc -> ldc_w rewriting, then we 2166 // always need a new_index value. 2167 new_index = cp_index; 2168 } 2169 if (new_index != 0) { 2170 // the original index is mapped so we have more work to do 2171 if (!StressLdcRewrite && new_index <= max_jubyte) { 2172 // The new value can still use ldc instead of ldc_w 2173 // unless we are trying to stress ldc -> ldc_w rewriting 2174 log_trace(redefine, class, constantpool) 2175 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index); 2176 // We checked that new_index fits in a u1 so this cast is safe 2177 *(bcp + 1) = (u1)new_index; 2178 } else { 2179 log_trace(redefine, class, constantpool) 2180 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index); 2181 // the new value needs ldc_w instead of ldc 2182 u_char inst_buffer[4]; // max instruction size is 4 bytes 2183 bcp = (address)inst_buffer; 2184 // construct new instruction sequence 2185 *bcp = Bytecodes::_ldc_w; 2186 bcp++; 2187 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w. 2188 // See comment below for difference between put_Java_u2() 2189 // and put_native_u2(). 2190 Bytes::put_Java_u2(bcp, new_index); 2191 2192 Relocator rc(method, nullptr /* no RelocatorListener needed */); 2193 methodHandle m; 2194 { 2195 PauseNoSafepointVerifier pnsv(&nsv); 2196 2197 // ldc is 2 bytes and ldc_w is 3 bytes 2198 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK); 2199 } 2200 2201 // return the new method so that the caller can update 2202 // the containing class 2203 *new_method_p = method = m; 2204 // switch our bytecode processing loop from the old method 2205 // to the new method 2206 code_base = method->code_base(); 2207 code_length = method->code_size(); 2208 bcp = code_base + bci; 2209 c = (Bytecodes::Code)(*bcp); 2210 bc_length = Bytecodes::length_for(c); 2211 assert(bc_length != 0, "sanity check"); 2212 } // end we need ldc_w instead of ldc 2213 } // end if there is a mapped index 2214 } break; 2215 2216 // these bytecodes have a two-byte constant pool index 2217 case Bytecodes::_anewarray : // fall through 2218 case Bytecodes::_checkcast : // fall through 2219 case Bytecodes::_getfield : // fall through 2220 case Bytecodes::_getstatic : // fall through 2221 case Bytecodes::_instanceof : // fall through 2222 case Bytecodes::_invokedynamic : // fall through 2223 case Bytecodes::_invokeinterface: // fall through 2224 case Bytecodes::_invokespecial : // fall through 2225 case Bytecodes::_invokestatic : // fall through 2226 case Bytecodes::_invokevirtual : // fall through 2227 case Bytecodes::_ldc_w : // fall through 2228 case Bytecodes::_ldc2_w : // fall through 2229 case Bytecodes::_multianewarray : // fall through 2230 case Bytecodes::_new : // fall through 2231 case Bytecodes::_putfield : // fall through 2232 case Bytecodes::_putstatic : 2233 { 2234 address p = bcp + 1; 2235 int cp_index = Bytes::get_Java_u2(p); 2236 u2 new_index = find_new_index(cp_index); 2237 if (new_index != 0) { 2238 // the original index is mapped so update w/ new value 2239 log_trace(redefine, class, constantpool) 2240 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),p2i(bcp), cp_index, new_index); 2241 // Rewriter::rewrite_method() uses put_native_u2() in this 2242 // situation because it is reusing the constant pool index 2243 // location for a native index into the ConstantPoolCache. 2244 // Since we are updating the constant pool index prior to 2245 // verification and ConstantPoolCache initialization, we 2246 // need to keep the new index in Java byte order. 2247 Bytes::put_Java_u2(p, new_index); 2248 } 2249 } break; 2250 default: 2251 break; 2252 } 2253 } // end for each bytecode 2254 } // end rewrite_cp_refs_in_method() 2255 2256 2257 // Rewrite constant pool references in the class_annotations field. 2258 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(InstanceKlass* scratch_class) { 2259 2260 AnnotationArray* class_annotations = scratch_class->class_annotations(); 2261 if (class_annotations == nullptr || class_annotations->length() == 0) { 2262 // no class_annotations so nothing to do 2263 return true; 2264 } 2265 2266 log_debug(redefine, class, annotation)("class_annotations length=%d", class_annotations->length()); 2267 2268 int byte_i = 0; // byte index into class_annotations 2269 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i); 2270 } 2271 2272 2273 // Rewrite constant pool references in an annotations typeArray. This 2274 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute 2275 // that is described in section 4.8.15 of the 2nd-edition of the VM spec: 2276 // 2277 // annotations_typeArray { 2278 // u2 num_annotations; 2279 // annotation annotations[num_annotations]; 2280 // } 2281 // 2282 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray( 2283 AnnotationArray* annotations_typeArray, int &byte_i_ref) { 2284 2285 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2286 // not enough room for num_annotations field 2287 log_debug(redefine, class, annotation)("length() is too small for num_annotations field"); 2288 return false; 2289 } 2290 2291 u2 num_annotations = Bytes::get_Java_u2((address) 2292 annotations_typeArray->adr_at(byte_i_ref)); 2293 byte_i_ref += 2; 2294 2295 log_debug(redefine, class, annotation)("num_annotations=%d", num_annotations); 2296 2297 int calc_num_annotations = 0; 2298 for (; calc_num_annotations < num_annotations; calc_num_annotations++) { 2299 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, byte_i_ref)) { 2300 log_debug(redefine, class, annotation)("bad annotation_struct at %d", calc_num_annotations); 2301 // propagate failure back to caller 2302 return false; 2303 } 2304 } 2305 assert(num_annotations == calc_num_annotations, "sanity check"); 2306 2307 return true; 2308 } // end rewrite_cp_refs_in_annotations_typeArray() 2309 2310 2311 // Rewrite constant pool references in the annotation struct portion of 2312 // an annotations_typeArray. This "structure" is from section 4.8.15 of 2313 // the 2nd-edition of the VM spec: 2314 // 2315 // struct annotation { 2316 // u2 type_index; 2317 // u2 num_element_value_pairs; 2318 // { 2319 // u2 element_name_index; 2320 // element_value value; 2321 // } element_value_pairs[num_element_value_pairs]; 2322 // } 2323 // 2324 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct( 2325 AnnotationArray* annotations_typeArray, int &byte_i_ref) { 2326 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) { 2327 // not enough room for smallest annotation_struct 2328 log_debug(redefine, class, annotation)("length() is too small for annotation_struct"); 2329 return false; 2330 } 2331 2332 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray, 2333 byte_i_ref, "type_index"); 2334 2335 u2 num_element_value_pairs = Bytes::get_Java_u2((address) 2336 annotations_typeArray->adr_at(byte_i_ref)); 2337 byte_i_ref += 2; 2338 2339 log_debug(redefine, class, annotation) 2340 ("type_index=%d num_element_value_pairs=%d", type_index, num_element_value_pairs); 2341 2342 int calc_num_element_value_pairs = 0; 2343 for (; calc_num_element_value_pairs < num_element_value_pairs; 2344 calc_num_element_value_pairs++) { 2345 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2346 // not enough room for another element_name_index, let alone 2347 // the rest of another component 2348 log_debug(redefine, class, annotation)("length() is too small for element_name_index"); 2349 return false; 2350 } 2351 2352 u2 element_name_index = rewrite_cp_ref_in_annotation_data( 2353 annotations_typeArray, byte_i_ref, 2354 "element_name_index"); 2355 2356 log_debug(redefine, class, annotation)("element_name_index=%d", element_name_index); 2357 2358 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, byte_i_ref)) { 2359 log_debug(redefine, class, annotation)("bad element_value at %d", calc_num_element_value_pairs); 2360 // propagate failure back to caller 2361 return false; 2362 } 2363 } // end for each component 2364 assert(num_element_value_pairs == calc_num_element_value_pairs, 2365 "sanity check"); 2366 2367 return true; 2368 } // end rewrite_cp_refs_in_annotation_struct() 2369 2370 2371 // Rewrite a constant pool reference at the current position in 2372 // annotations_typeArray if needed. Returns the original constant 2373 // pool reference if a rewrite was not needed or the new constant 2374 // pool reference if a rewrite was needed. 2375 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data( 2376 AnnotationArray* annotations_typeArray, int &byte_i_ref, 2377 const char * trace_mesg) { 2378 2379 address cp_index_addr = (address) 2380 annotations_typeArray->adr_at(byte_i_ref); 2381 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr); 2382 u2 new_cp_index = find_new_index(old_cp_index); 2383 if (new_cp_index != 0) { 2384 log_debug(redefine, class, annotation)("mapped old %s=%d", trace_mesg, old_cp_index); 2385 Bytes::put_Java_u2(cp_index_addr, new_cp_index); 2386 old_cp_index = new_cp_index; 2387 } 2388 byte_i_ref += 2; 2389 return old_cp_index; 2390 } 2391 2392 2393 // Rewrite constant pool references in the element_value portion of an 2394 // annotations_typeArray. This "structure" is from section 4.8.15.1 of 2395 // the 2nd-edition of the VM spec: 2396 // 2397 // struct element_value { 2398 // u1 tag; 2399 // union { 2400 // u2 const_value_index; 2401 // { 2402 // u2 type_name_index; 2403 // u2 const_name_index; 2404 // } enum_const_value; 2405 // u2 class_info_index; 2406 // annotation annotation_value; 2407 // struct { 2408 // u2 num_values; 2409 // element_value values[num_values]; 2410 // } array_value; 2411 // } value; 2412 // } 2413 // 2414 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value( 2415 AnnotationArray* annotations_typeArray, int &byte_i_ref) { 2416 2417 if ((byte_i_ref + 1) > annotations_typeArray->length()) { 2418 // not enough room for a tag let alone the rest of an element_value 2419 log_debug(redefine, class, annotation)("length() is too small for a tag"); 2420 return false; 2421 } 2422 2423 u1 tag = annotations_typeArray->at(byte_i_ref); 2424 byte_i_ref++; 2425 log_debug(redefine, class, annotation)("tag='%c'", tag); 2426 2427 switch (tag) { 2428 // These BaseType tag values are from Table 4.2 in VM spec: 2429 case JVM_SIGNATURE_BYTE: 2430 case JVM_SIGNATURE_CHAR: 2431 case JVM_SIGNATURE_DOUBLE: 2432 case JVM_SIGNATURE_FLOAT: 2433 case JVM_SIGNATURE_INT: 2434 case JVM_SIGNATURE_LONG: 2435 case JVM_SIGNATURE_SHORT: 2436 case JVM_SIGNATURE_BOOLEAN: 2437 2438 // The remaining tag values are from Table 4.8 in the 2nd-edition of 2439 // the VM spec: 2440 case 's': 2441 { 2442 // For the above tag values (including the BaseType values), 2443 // value.const_value_index is right union field. 2444 2445 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2446 // not enough room for a const_value_index 2447 log_debug(redefine, class, annotation)("length() is too small for a const_value_index"); 2448 return false; 2449 } 2450 2451 u2 const_value_index = rewrite_cp_ref_in_annotation_data( 2452 annotations_typeArray, byte_i_ref, 2453 "const_value_index"); 2454 2455 log_debug(redefine, class, annotation)("const_value_index=%d", const_value_index); 2456 } break; 2457 2458 case 'e': 2459 { 2460 // for the above tag value, value.enum_const_value is right union field 2461 2462 if ((byte_i_ref + 4) > annotations_typeArray->length()) { 2463 // not enough room for a enum_const_value 2464 log_debug(redefine, class, annotation)("length() is too small for a enum_const_value"); 2465 return false; 2466 } 2467 2468 u2 type_name_index = rewrite_cp_ref_in_annotation_data( 2469 annotations_typeArray, byte_i_ref, 2470 "type_name_index"); 2471 2472 u2 const_name_index = rewrite_cp_ref_in_annotation_data( 2473 annotations_typeArray, byte_i_ref, 2474 "const_name_index"); 2475 2476 log_debug(redefine, class, annotation) 2477 ("type_name_index=%d const_name_index=%d", type_name_index, const_name_index); 2478 } break; 2479 2480 case 'c': 2481 { 2482 // for the above tag value, value.class_info_index is right union field 2483 2484 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2485 // not enough room for a class_info_index 2486 log_debug(redefine, class, annotation)("length() is too small for a class_info_index"); 2487 return false; 2488 } 2489 2490 u2 class_info_index = rewrite_cp_ref_in_annotation_data( 2491 annotations_typeArray, byte_i_ref, 2492 "class_info_index"); 2493 2494 log_debug(redefine, class, annotation)("class_info_index=%d", class_info_index); 2495 } break; 2496 2497 case '@': 2498 // For the above tag value, value.attr_value is the right union 2499 // field. This is a nested annotation. 2500 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, byte_i_ref)) { 2501 // propagate failure back to caller 2502 return false; 2503 } 2504 break; 2505 2506 case JVM_SIGNATURE_ARRAY: 2507 { 2508 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2509 // not enough room for a num_values field 2510 log_debug(redefine, class, annotation)("length() is too small for a num_values field"); 2511 return false; 2512 } 2513 2514 // For the above tag value, value.array_value is the right union 2515 // field. This is an array of nested element_value. 2516 u2 num_values = Bytes::get_Java_u2((address) 2517 annotations_typeArray->adr_at(byte_i_ref)); 2518 byte_i_ref += 2; 2519 log_debug(redefine, class, annotation)("num_values=%d", num_values); 2520 2521 int calc_num_values = 0; 2522 for (; calc_num_values < num_values; calc_num_values++) { 2523 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, byte_i_ref)) { 2524 log_debug(redefine, class, annotation)("bad nested element_value at %d", calc_num_values); 2525 // propagate failure back to caller 2526 return false; 2527 } 2528 } 2529 assert(num_values == calc_num_values, "sanity check"); 2530 } break; 2531 2532 default: 2533 log_debug(redefine, class, annotation)("bad tag=0x%x", tag); 2534 return false; 2535 } // end decode tag field 2536 2537 return true; 2538 } // end rewrite_cp_refs_in_element_value() 2539 2540 2541 // Rewrite constant pool references in a fields_annotations field. 2542 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations( 2543 InstanceKlass* scratch_class) { 2544 2545 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations(); 2546 2547 if (fields_annotations == nullptr || fields_annotations->length() == 0) { 2548 // no fields_annotations so nothing to do 2549 return true; 2550 } 2551 2552 log_debug(redefine, class, annotation)("fields_annotations length=%d", fields_annotations->length()); 2553 2554 for (int i = 0; i < fields_annotations->length(); i++) { 2555 AnnotationArray* field_annotations = fields_annotations->at(i); 2556 if (field_annotations == nullptr || field_annotations->length() == 0) { 2557 // this field does not have any annotations so skip it 2558 continue; 2559 } 2560 2561 int byte_i = 0; // byte index into field_annotations 2562 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i)) { 2563 log_debug(redefine, class, annotation)("bad field_annotations at %d", i); 2564 // propagate failure back to caller 2565 return false; 2566 } 2567 } 2568 2569 return true; 2570 } // end rewrite_cp_refs_in_fields_annotations() 2571 2572 2573 // Rewrite constant pool references in a methods_annotations field. 2574 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations( 2575 InstanceKlass* scratch_class) { 2576 2577 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2578 Method* m = scratch_class->methods()->at(i); 2579 AnnotationArray* method_annotations = m->constMethod()->method_annotations(); 2580 2581 if (method_annotations == nullptr || method_annotations->length() == 0) { 2582 // this method does not have any annotations so skip it 2583 continue; 2584 } 2585 2586 int byte_i = 0; // byte index into method_annotations 2587 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i)) { 2588 log_debug(redefine, class, annotation)("bad method_annotations at %d", i); 2589 // propagate failure back to caller 2590 return false; 2591 } 2592 } 2593 2594 return true; 2595 } // end rewrite_cp_refs_in_methods_annotations() 2596 2597 2598 // Rewrite constant pool references in a methods_parameter_annotations 2599 // field. This "structure" is adapted from the 2600 // RuntimeVisibleParameterAnnotations_attribute described in section 2601 // 4.8.17 of the 2nd-edition of the VM spec: 2602 // 2603 // methods_parameter_annotations_typeArray { 2604 // u1 num_parameters; 2605 // { 2606 // u2 num_annotations; 2607 // annotation annotations[num_annotations]; 2608 // } parameter_annotations[num_parameters]; 2609 // } 2610 // 2611 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations( 2612 InstanceKlass* scratch_class) { 2613 2614 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2615 Method* m = scratch_class->methods()->at(i); 2616 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations(); 2617 if (method_parameter_annotations == nullptr 2618 || method_parameter_annotations->length() == 0) { 2619 // this method does not have any parameter annotations so skip it 2620 continue; 2621 } 2622 2623 if (method_parameter_annotations->length() < 1) { 2624 // not enough room for a num_parameters field 2625 log_debug(redefine, class, annotation)("length() is too small for a num_parameters field at %d", i); 2626 return false; 2627 } 2628 2629 int byte_i = 0; // byte index into method_parameter_annotations 2630 2631 u1 num_parameters = method_parameter_annotations->at(byte_i); 2632 byte_i++; 2633 2634 log_debug(redefine, class, annotation)("num_parameters=%d", num_parameters); 2635 2636 int calc_num_parameters = 0; 2637 for (; calc_num_parameters < num_parameters; calc_num_parameters++) { 2638 if (!rewrite_cp_refs_in_annotations_typeArray(method_parameter_annotations, byte_i)) { 2639 log_debug(redefine, class, annotation)("bad method_parameter_annotations at %d", calc_num_parameters); 2640 // propagate failure back to caller 2641 return false; 2642 } 2643 } 2644 assert(num_parameters == calc_num_parameters, "sanity check"); 2645 } 2646 2647 return true; 2648 } // end rewrite_cp_refs_in_methods_parameter_annotations() 2649 2650 2651 // Rewrite constant pool references in a methods_default_annotations 2652 // field. This "structure" is adapted from the AnnotationDefault_attribute 2653 // that is described in section 4.8.19 of the 2nd-edition of the VM spec: 2654 // 2655 // methods_default_annotations_typeArray { 2656 // element_value default_value; 2657 // } 2658 // 2659 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations( 2660 InstanceKlass* scratch_class) { 2661 2662 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2663 Method* m = scratch_class->methods()->at(i); 2664 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations(); 2665 if (method_default_annotations == nullptr 2666 || method_default_annotations->length() == 0) { 2667 // this method does not have any default annotations so skip it 2668 continue; 2669 } 2670 2671 int byte_i = 0; // byte index into method_default_annotations 2672 2673 if (!rewrite_cp_refs_in_element_value( 2674 method_default_annotations, byte_i)) { 2675 log_debug(redefine, class, annotation)("bad default element_value at %d", i); 2676 // propagate failure back to caller 2677 return false; 2678 } 2679 } 2680 2681 return true; 2682 } // end rewrite_cp_refs_in_methods_default_annotations() 2683 2684 2685 // Rewrite constant pool references in a class_type_annotations field. 2686 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations( 2687 InstanceKlass* scratch_class) { 2688 2689 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations(); 2690 if (class_type_annotations == nullptr || class_type_annotations->length() == 0) { 2691 // no class_type_annotations so nothing to do 2692 return true; 2693 } 2694 2695 log_debug(redefine, class, annotation)("class_type_annotations length=%d", class_type_annotations->length()); 2696 2697 int byte_i = 0; // byte index into class_type_annotations 2698 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations, 2699 byte_i, "ClassFile"); 2700 } // end rewrite_cp_refs_in_class_type_annotations() 2701 2702 2703 // Rewrite constant pool references in a fields_type_annotations field. 2704 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations(InstanceKlass* scratch_class) { 2705 2706 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations(); 2707 if (fields_type_annotations == nullptr || fields_type_annotations->length() == 0) { 2708 // no fields_type_annotations so nothing to do 2709 return true; 2710 } 2711 2712 log_debug(redefine, class, annotation)("fields_type_annotations length=%d", fields_type_annotations->length()); 2713 2714 for (int i = 0; i < fields_type_annotations->length(); i++) { 2715 AnnotationArray* field_type_annotations = fields_type_annotations->at(i); 2716 if (field_type_annotations == nullptr || field_type_annotations->length() == 0) { 2717 // this field does not have any annotations so skip it 2718 continue; 2719 } 2720 2721 int byte_i = 0; // byte index into field_type_annotations 2722 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations, 2723 byte_i, "field_info")) { 2724 log_debug(redefine, class, annotation)("bad field_type_annotations at %d", i); 2725 // propagate failure back to caller 2726 return false; 2727 } 2728 } 2729 2730 return true; 2731 } // end rewrite_cp_refs_in_fields_type_annotations() 2732 2733 2734 // Rewrite constant pool references in a methods_type_annotations field. 2735 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations( 2736 InstanceKlass* scratch_class) { 2737 2738 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2739 Method* m = scratch_class->methods()->at(i); 2740 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations(); 2741 2742 if (method_type_annotations == nullptr || method_type_annotations->length() == 0) { 2743 // this method does not have any annotations so skip it 2744 continue; 2745 } 2746 2747 log_debug(redefine, class, annotation)("methods type_annotations length=%d", method_type_annotations->length()); 2748 2749 int byte_i = 0; // byte index into method_type_annotations 2750 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations, 2751 byte_i, "method_info")) { 2752 log_debug(redefine, class, annotation)("bad method_type_annotations at %d", i); 2753 // propagate failure back to caller 2754 return false; 2755 } 2756 } 2757 2758 return true; 2759 } // end rewrite_cp_refs_in_methods_type_annotations() 2760 2761 2762 // Rewrite constant pool references in a type_annotations 2763 // field. This "structure" is adapted from the 2764 // RuntimeVisibleTypeAnnotations_attribute described in 2765 // section 4.7.20 of the Java SE 8 Edition of the VM spec: 2766 // 2767 // type_annotations_typeArray { 2768 // u2 num_annotations; 2769 // type_annotation annotations[num_annotations]; 2770 // } 2771 // 2772 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray( 2773 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2774 const char * location_mesg) { 2775 2776 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2777 // not enough room for num_annotations field 2778 log_debug(redefine, class, annotation)("length() is too small for num_annotations field"); 2779 return false; 2780 } 2781 2782 u2 num_annotations = Bytes::get_Java_u2((address) 2783 type_annotations_typeArray->adr_at(byte_i_ref)); 2784 byte_i_ref += 2; 2785 2786 log_debug(redefine, class, annotation)("num_type_annotations=%d", num_annotations); 2787 2788 int calc_num_annotations = 0; 2789 for (; calc_num_annotations < num_annotations; calc_num_annotations++) { 2790 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray, 2791 byte_i_ref, location_mesg)) { 2792 log_debug(redefine, class, annotation)("bad type_annotation_struct at %d", calc_num_annotations); 2793 // propagate failure back to caller 2794 return false; 2795 } 2796 } 2797 assert(num_annotations == calc_num_annotations, "sanity check"); 2798 2799 if (byte_i_ref != type_annotations_typeArray->length()) { 2800 log_debug(redefine, class, annotation) 2801 ("read wrong amount of bytes at end of processing type_annotations_typeArray (%d of %d bytes were read)", 2802 byte_i_ref, type_annotations_typeArray->length()); 2803 return false; 2804 } 2805 2806 return true; 2807 } // end rewrite_cp_refs_in_type_annotations_typeArray() 2808 2809 2810 // Rewrite constant pool references in a type_annotation 2811 // field. This "structure" is adapted from the 2812 // RuntimeVisibleTypeAnnotations_attribute described in 2813 // section 4.7.20 of the Java SE 8 Edition of the VM spec: 2814 // 2815 // type_annotation { 2816 // u1 target_type; 2817 // union { 2818 // type_parameter_target; 2819 // supertype_target; 2820 // type_parameter_bound_target; 2821 // empty_target; 2822 // method_formal_parameter_target; 2823 // throws_target; 2824 // localvar_target; 2825 // catch_target; 2826 // offset_target; 2827 // type_argument_target; 2828 // } target_info; 2829 // type_path target_path; 2830 // annotation anno; 2831 // } 2832 // 2833 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct( 2834 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2835 const char * location_mesg) { 2836 2837 if (!skip_type_annotation_target(type_annotations_typeArray, 2838 byte_i_ref, location_mesg)) { 2839 return false; 2840 } 2841 2842 if (!skip_type_annotation_type_path(type_annotations_typeArray, byte_i_ref)) { 2843 return false; 2844 } 2845 2846 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray, byte_i_ref)) { 2847 return false; 2848 } 2849 2850 return true; 2851 } // end rewrite_cp_refs_in_type_annotation_struct() 2852 2853 2854 // Read, verify and skip over the target_type and target_info part 2855 // so that rewriting can continue in the later parts of the struct. 2856 // 2857 // u1 target_type; 2858 // union { 2859 // type_parameter_target; 2860 // supertype_target; 2861 // type_parameter_bound_target; 2862 // empty_target; 2863 // method_formal_parameter_target; 2864 // throws_target; 2865 // localvar_target; 2866 // catch_target; 2867 // offset_target; 2868 // type_argument_target; 2869 // } target_info; 2870 // 2871 bool VM_RedefineClasses::skip_type_annotation_target( 2872 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2873 const char * location_mesg) { 2874 2875 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2876 // not enough room for a target_type let alone the rest of a type_annotation 2877 log_debug(redefine, class, annotation)("length() is too small for a target_type"); 2878 return false; 2879 } 2880 2881 u1 target_type = type_annotations_typeArray->at(byte_i_ref); 2882 byte_i_ref += 1; 2883 log_debug(redefine, class, annotation)("target_type=0x%.2x", target_type); 2884 log_debug(redefine, class, annotation)("location=%s", location_mesg); 2885 2886 // Skip over target_info 2887 switch (target_type) { 2888 case 0x00: 2889 // kind: type parameter declaration of generic class or interface 2890 // location: ClassFile 2891 case 0x01: 2892 // kind: type parameter declaration of generic method or constructor 2893 // location: method_info 2894 2895 { 2896 // struct: 2897 // type_parameter_target { 2898 // u1 type_parameter_index; 2899 // } 2900 // 2901 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2902 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_target"); 2903 return false; 2904 } 2905 2906 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2907 byte_i_ref += 1; 2908 2909 log_debug(redefine, class, annotation)("type_parameter_target: type_parameter_index=%d", type_parameter_index); 2910 } break; 2911 2912 case 0x10: 2913 // kind: type in extends clause of class or interface declaration 2914 // or in implements clause of interface declaration 2915 // location: ClassFile 2916 2917 { 2918 // struct: 2919 // supertype_target { 2920 // u2 supertype_index; 2921 // } 2922 // 2923 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2924 log_debug(redefine, class, annotation)("length() is too small for a supertype_target"); 2925 return false; 2926 } 2927 2928 u2 supertype_index = Bytes::get_Java_u2((address) 2929 type_annotations_typeArray->adr_at(byte_i_ref)); 2930 byte_i_ref += 2; 2931 2932 log_debug(redefine, class, annotation)("supertype_target: supertype_index=%d", supertype_index); 2933 } break; 2934 2935 case 0x11: 2936 // kind: type in bound of type parameter declaration of generic class or interface 2937 // location: ClassFile 2938 case 0x12: 2939 // kind: type in bound of type parameter declaration of generic method or constructor 2940 // location: method_info 2941 2942 { 2943 // struct: 2944 // type_parameter_bound_target { 2945 // u1 type_parameter_index; 2946 // u1 bound_index; 2947 // } 2948 // 2949 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2950 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_bound_target"); 2951 return false; 2952 } 2953 2954 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2955 byte_i_ref += 1; 2956 u1 bound_index = type_annotations_typeArray->at(byte_i_ref); 2957 byte_i_ref += 1; 2958 2959 log_debug(redefine, class, annotation) 2960 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d", type_parameter_index, bound_index); 2961 } break; 2962 2963 case 0x13: 2964 // kind: type in field declaration 2965 // location: field_info 2966 case 0x14: 2967 // kind: return type of method, or type of newly constructed object 2968 // location: method_info 2969 case 0x15: 2970 // kind: receiver type of method or constructor 2971 // location: method_info 2972 2973 { 2974 // struct: 2975 // empty_target { 2976 // } 2977 // 2978 log_debug(redefine, class, annotation)("empty_target"); 2979 } break; 2980 2981 case 0x16: 2982 // kind: type in formal parameter declaration of method, constructor, or lambda expression 2983 // location: method_info 2984 2985 { 2986 // struct: 2987 // formal_parameter_target { 2988 // u1 formal_parameter_index; 2989 // } 2990 // 2991 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2992 log_debug(redefine, class, annotation)("length() is too small for a formal_parameter_target"); 2993 return false; 2994 } 2995 2996 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2997 byte_i_ref += 1; 2998 2999 log_debug(redefine, class, annotation) 3000 ("formal_parameter_target: formal_parameter_index=%d", formal_parameter_index); 3001 } break; 3002 3003 case 0x17: 3004 // kind: type in throws clause of method or constructor 3005 // location: method_info 3006 3007 { 3008 // struct: 3009 // throws_target { 3010 // u2 throws_type_index 3011 // } 3012 // 3013 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 3014 log_debug(redefine, class, annotation)("length() is too small for a throws_target"); 3015 return false; 3016 } 3017 3018 u2 throws_type_index = Bytes::get_Java_u2((address) 3019 type_annotations_typeArray->adr_at(byte_i_ref)); 3020 byte_i_ref += 2; 3021 3022 log_debug(redefine, class, annotation)("throws_target: throws_type_index=%d", throws_type_index); 3023 } break; 3024 3025 case 0x40: 3026 // kind: type in local variable declaration 3027 // location: Code 3028 case 0x41: 3029 // kind: type in resource variable declaration 3030 // location: Code 3031 3032 { 3033 // struct: 3034 // localvar_target { 3035 // u2 table_length; 3036 // struct { 3037 // u2 start_pc; 3038 // u2 length; 3039 // u2 index; 3040 // } table[table_length]; 3041 // } 3042 // 3043 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 3044 // not enough room for a table_length let alone the rest of a localvar_target 3045 log_debug(redefine, class, annotation)("length() is too small for a localvar_target table_length"); 3046 return false; 3047 } 3048 3049 u2 table_length = Bytes::get_Java_u2((address) 3050 type_annotations_typeArray->adr_at(byte_i_ref)); 3051 byte_i_ref += 2; 3052 3053 log_debug(redefine, class, annotation)("localvar_target: table_length=%d", table_length); 3054 3055 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry 3056 int table_size = table_length * table_struct_size; 3057 3058 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) { 3059 // not enough room for a table 3060 log_debug(redefine, class, annotation)("length() is too small for a table array of length %d", table_length); 3061 return false; 3062 } 3063 3064 // Skip over table 3065 byte_i_ref += table_size; 3066 } break; 3067 3068 case 0x42: 3069 // kind: type in exception parameter declaration 3070 // location: Code 3071 3072 { 3073 // struct: 3074 // catch_target { 3075 // u2 exception_table_index; 3076 // } 3077 // 3078 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 3079 log_debug(redefine, class, annotation)("length() is too small for a catch_target"); 3080 return false; 3081 } 3082 3083 u2 exception_table_index = Bytes::get_Java_u2((address) 3084 type_annotations_typeArray->adr_at(byte_i_ref)); 3085 byte_i_ref += 2; 3086 3087 log_debug(redefine, class, annotation)("catch_target: exception_table_index=%d", exception_table_index); 3088 } break; 3089 3090 case 0x43: 3091 // kind: type in instanceof expression 3092 // location: Code 3093 case 0x44: 3094 // kind: type in new expression 3095 // location: Code 3096 case 0x45: 3097 // kind: type in method reference expression using ::new 3098 // location: Code 3099 case 0x46: 3100 // kind: type in method reference expression using ::Identifier 3101 // location: Code 3102 3103 { 3104 // struct: 3105 // offset_target { 3106 // u2 offset; 3107 // } 3108 // 3109 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 3110 log_debug(redefine, class, annotation)("length() is too small for a offset_target"); 3111 return false; 3112 } 3113 3114 u2 offset = Bytes::get_Java_u2((address) 3115 type_annotations_typeArray->adr_at(byte_i_ref)); 3116 byte_i_ref += 2; 3117 3118 log_debug(redefine, class, annotation)("offset_target: offset=%d", offset); 3119 } break; 3120 3121 case 0x47: 3122 // kind: type in cast expression 3123 // location: Code 3124 case 0x48: 3125 // kind: type argument for generic constructor in new expression or 3126 // explicit constructor invocation statement 3127 // location: Code 3128 case 0x49: 3129 // kind: type argument for generic method in method invocation expression 3130 // location: Code 3131 case 0x4A: 3132 // kind: type argument for generic constructor in method reference expression using ::new 3133 // location: Code 3134 case 0x4B: 3135 // kind: type argument for generic method in method reference expression using ::Identifier 3136 // location: Code 3137 3138 { 3139 // struct: 3140 // type_argument_target { 3141 // u2 offset; 3142 // u1 type_argument_index; 3143 // } 3144 // 3145 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) { 3146 log_debug(redefine, class, annotation)("length() is too small for a type_argument_target"); 3147 return false; 3148 } 3149 3150 u2 offset = Bytes::get_Java_u2((address) 3151 type_annotations_typeArray->adr_at(byte_i_ref)); 3152 byte_i_ref += 2; 3153 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref); 3154 byte_i_ref += 1; 3155 3156 log_debug(redefine, class, annotation) 3157 ("type_argument_target: offset=%d, type_argument_index=%d", offset, type_argument_index); 3158 } break; 3159 3160 default: 3161 log_debug(redefine, class, annotation)("unknown target_type"); 3162 #ifdef ASSERT 3163 ShouldNotReachHere(); 3164 #endif 3165 return false; 3166 } 3167 3168 return true; 3169 } // end skip_type_annotation_target() 3170 3171 3172 // Read, verify and skip over the type_path part so that rewriting 3173 // can continue in the later parts of the struct. 3174 // 3175 // type_path { 3176 // u1 path_length; 3177 // { 3178 // u1 type_path_kind; 3179 // u1 type_argument_index; 3180 // } path[path_length]; 3181 // } 3182 // 3183 bool VM_RedefineClasses::skip_type_annotation_type_path( 3184 AnnotationArray* type_annotations_typeArray, int &byte_i_ref) { 3185 3186 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 3187 // not enough room for a path_length let alone the rest of the type_path 3188 log_debug(redefine, class, annotation)("length() is too small for a type_path"); 3189 return false; 3190 } 3191 3192 u1 path_length = type_annotations_typeArray->at(byte_i_ref); 3193 byte_i_ref += 1; 3194 3195 log_debug(redefine, class, annotation)("type_path: path_length=%d", path_length); 3196 3197 int calc_path_length = 0; 3198 for (; calc_path_length < path_length; calc_path_length++) { 3199 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) { 3200 // not enough room for a path 3201 log_debug(redefine, class, annotation) 3202 ("length() is too small for path entry %d of %d", calc_path_length, path_length); 3203 return false; 3204 } 3205 3206 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref); 3207 byte_i_ref += 1; 3208 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref); 3209 byte_i_ref += 1; 3210 3211 log_debug(redefine, class, annotation) 3212 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d", 3213 calc_path_length, type_path_kind, type_argument_index); 3214 3215 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) { 3216 // not enough room for a path 3217 log_debug(redefine, class, annotation)("inconsistent type_path values"); 3218 return false; 3219 } 3220 } 3221 assert(path_length == calc_path_length, "sanity check"); 3222 3223 return true; 3224 } // end skip_type_annotation_type_path() 3225 3226 3227 // Rewrite constant pool references in the method's stackmap table. 3228 // These "structures" are adapted from the StackMapTable_attribute that 3229 // is described in section 4.8.4 of the 6.0 version of the VM spec 3230 // (dated 2005.10.26): 3231 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf 3232 // 3233 // stack_map { 3234 // u2 number_of_entries; 3235 // stack_map_frame entries[number_of_entries]; 3236 // } 3237 // 3238 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table( 3239 const methodHandle& method) { 3240 3241 if (!method->has_stackmap_table()) { 3242 return; 3243 } 3244 3245 AnnotationArray* stackmap_data = method->stackmap_data(); 3246 address stackmap_p = (address)stackmap_data->adr_at(0); 3247 address stackmap_end = stackmap_p + stackmap_data->length(); 3248 3249 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries"); 3250 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p); 3251 stackmap_p += 2; 3252 3253 log_debug(redefine, class, stackmap)("number_of_entries=%u", number_of_entries); 3254 3255 // walk through each stack_map_frame 3256 u2 calc_number_of_entries = 0; 3257 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) { 3258 // The stack_map_frame structure is a u1 frame_type followed by 3259 // 0 or more bytes of data: 3260 // 3261 // union stack_map_frame { 3262 // same_frame; 3263 // same_locals_1_stack_item_frame; 3264 // same_locals_1_stack_item_frame_extended; 3265 // chop_frame; 3266 // same_frame_extended; 3267 // append_frame; 3268 // full_frame; 3269 // } 3270 3271 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type"); 3272 u1 frame_type = *stackmap_p; 3273 stackmap_p++; 3274 3275 // same_frame { 3276 // u1 frame_type = SAME; /* 0-63 */ 3277 // } 3278 if (frame_type <= 63) { 3279 // nothing more to do for same_frame 3280 } 3281 3282 // same_locals_1_stack_item_frame { 3283 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */ 3284 // verification_type_info stack[1]; 3285 // } 3286 else if (frame_type >= 64 && frame_type <= 127) { 3287 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3288 calc_number_of_entries, frame_type); 3289 } 3290 3291 // reserved for future use 3292 else if (frame_type >= 128 && frame_type <= 246) { 3293 // nothing more to do for reserved frame_types 3294 } 3295 3296 // same_locals_1_stack_item_frame_extended { 3297 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */ 3298 // u2 offset_delta; 3299 // verification_type_info stack[1]; 3300 // } 3301 else if (frame_type == 247) { 3302 stackmap_p += 2; 3303 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3304 calc_number_of_entries, frame_type); 3305 } 3306 3307 // chop_frame { 3308 // u1 frame_type = CHOP; /* 248-250 */ 3309 // u2 offset_delta; 3310 // } 3311 else if (frame_type >= 248 && frame_type <= 250) { 3312 stackmap_p += 2; 3313 } 3314 3315 // same_frame_extended { 3316 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/ 3317 // u2 offset_delta; 3318 // } 3319 else if (frame_type == 251) { 3320 stackmap_p += 2; 3321 } 3322 3323 // append_frame { 3324 // u1 frame_type = APPEND; /* 252-254 */ 3325 // u2 offset_delta; 3326 // verification_type_info locals[frame_type - 251]; 3327 // } 3328 else if (frame_type >= 252 && frame_type <= 254) { 3329 assert(stackmap_p + 2 <= stackmap_end, 3330 "no room for offset_delta"); 3331 stackmap_p += 2; 3332 u1 len = frame_type - 251; 3333 for (u1 i = 0; i < len; i++) { 3334 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3335 calc_number_of_entries, frame_type); 3336 } 3337 } 3338 3339 // full_frame { 3340 // u1 frame_type = FULL_FRAME; /* 255 */ 3341 // u2 offset_delta; 3342 // u2 number_of_locals; 3343 // verification_type_info locals[number_of_locals]; 3344 // u2 number_of_stack_items; 3345 // verification_type_info stack[number_of_stack_items]; 3346 // } 3347 else if (frame_type == 255) { 3348 assert(stackmap_p + 2 + 2 <= stackmap_end, 3349 "no room for smallest full_frame"); 3350 stackmap_p += 2; 3351 3352 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p); 3353 stackmap_p += 2; 3354 3355 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) { 3356 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3357 calc_number_of_entries, frame_type); 3358 } 3359 3360 // Use the largest size for the number_of_stack_items, but only get 3361 // the right number of bytes. 3362 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p); 3363 stackmap_p += 2; 3364 3365 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) { 3366 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3367 calc_number_of_entries, frame_type); 3368 } 3369 } 3370 } // end while there is a stack_map_frame 3371 assert(number_of_entries == calc_number_of_entries, "sanity check"); 3372 } // end rewrite_cp_refs_in_stack_map_table() 3373 3374 3375 // Rewrite constant pool references in the verification type info 3376 // portion of the method's stackmap table. These "structures" are 3377 // adapted from the StackMapTable_attribute that is described in 3378 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26): 3379 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf 3380 // 3381 // The verification_type_info structure is a u1 tag followed by 0 or 3382 // more bytes of data: 3383 // 3384 // union verification_type_info { 3385 // Top_variable_info; 3386 // Integer_variable_info; 3387 // Float_variable_info; 3388 // Long_variable_info; 3389 // Double_variable_info; 3390 // Null_variable_info; 3391 // UninitializedThis_variable_info; 3392 // Object_variable_info; 3393 // Uninitialized_variable_info; 3394 // } 3395 // 3396 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info( 3397 address& stackmap_p_ref, address stackmap_end, u2 frame_i, 3398 u1 frame_type) { 3399 3400 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag"); 3401 u1 tag = *stackmap_p_ref; 3402 stackmap_p_ref++; 3403 3404 switch (tag) { 3405 // Top_variable_info { 3406 // u1 tag = ITEM_Top; /* 0 */ 3407 // } 3408 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top 3409 case 0: // fall through 3410 3411 // Integer_variable_info { 3412 // u1 tag = ITEM_Integer; /* 1 */ 3413 // } 3414 case ITEM_Integer: // fall through 3415 3416 // Float_variable_info { 3417 // u1 tag = ITEM_Float; /* 2 */ 3418 // } 3419 case ITEM_Float: // fall through 3420 3421 // Double_variable_info { 3422 // u1 tag = ITEM_Double; /* 3 */ 3423 // } 3424 case ITEM_Double: // fall through 3425 3426 // Long_variable_info { 3427 // u1 tag = ITEM_Long; /* 4 */ 3428 // } 3429 case ITEM_Long: // fall through 3430 3431 // Null_variable_info { 3432 // u1 tag = ITEM_Null; /* 5 */ 3433 // } 3434 case ITEM_Null: // fall through 3435 3436 // UninitializedThis_variable_info { 3437 // u1 tag = ITEM_UninitializedThis; /* 6 */ 3438 // } 3439 case ITEM_UninitializedThis: 3440 // nothing more to do for the above tag types 3441 break; 3442 3443 // Object_variable_info { 3444 // u1 tag = ITEM_Object; /* 7 */ 3445 // u2 cpool_index; 3446 // } 3447 case ITEM_Object: 3448 { 3449 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index"); 3450 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref); 3451 u2 new_cp_index = find_new_index(cpool_index); 3452 if (new_cp_index != 0) { 3453 log_debug(redefine, class, stackmap)("mapped old cpool_index=%d", cpool_index); 3454 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index); 3455 cpool_index = new_cp_index; 3456 } 3457 stackmap_p_ref += 2; 3458 3459 log_debug(redefine, class, stackmap) 3460 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i, frame_type, cpool_index); 3461 } break; 3462 3463 // Uninitialized_variable_info { 3464 // u1 tag = ITEM_Uninitialized; /* 8 */ 3465 // u2 offset; 3466 // } 3467 case ITEM_Uninitialized: 3468 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset"); 3469 stackmap_p_ref += 2; 3470 break; 3471 3472 default: 3473 log_debug(redefine, class, stackmap)("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag); 3474 ShouldNotReachHere(); 3475 break; 3476 } // end switch (tag) 3477 } // end rewrite_cp_refs_in_verification_type_info() 3478 3479 3480 // Change the constant pool associated with klass scratch_class to scratch_cp. 3481 // scratch_cp_length elements are copied from scratch_cp to a smaller constant pool 3482 // and the smaller constant pool is associated with scratch_class. 3483 void VM_RedefineClasses::set_new_constant_pool( 3484 ClassLoaderData* loader_data, 3485 InstanceKlass* scratch_class, constantPoolHandle scratch_cp, 3486 int scratch_cp_length, TRAPS) { 3487 assert(scratch_cp->length() >= scratch_cp_length, "sanity check"); 3488 3489 // scratch_cp is a merged constant pool and has enough space for a 3490 // worst case merge situation. We want to associate the minimum 3491 // sized constant pool with the klass to save space. 3492 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK); 3493 constantPoolHandle smaller_cp(THREAD, cp); 3494 3495 // preserve version() value in the smaller copy 3496 int version = scratch_cp->version(); 3497 assert(version != 0, "sanity check"); 3498 smaller_cp->set_version(version); 3499 3500 // attach klass to new constant pool 3501 // reference to the cp holder is needed for copy_operands() 3502 smaller_cp->set_pool_holder(scratch_class); 3503 3504 smaller_cp->copy_fields(scratch_cp()); 3505 3506 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD); 3507 if (HAS_PENDING_EXCEPTION) { 3508 // Exception is handled in the caller 3509 loader_data->add_to_deallocate_list(smaller_cp()); 3510 return; 3511 } 3512 scratch_cp = smaller_cp; 3513 3514 // attach new constant pool to klass 3515 scratch_class->set_constants(scratch_cp()); 3516 scratch_cp->initialize_unresolved_klasses(loader_data, CHECK); 3517 3518 int i; // for portability 3519 3520 // update each field in klass to use new constant pool indices as needed 3521 int java_fields; 3522 int injected_fields; 3523 bool update_required = false; 3524 GrowableArray<FieldInfo>* fields = FieldInfoStream::create_FieldInfoArray(scratch_class->fieldinfo_stream(), &java_fields, &injected_fields); 3525 for (int i = 0; i < java_fields; i++) { 3526 FieldInfo* fi = fields->adr_at(i); 3527 jshort cur_index = fi->name_index(); 3528 jshort new_index = find_new_index(cur_index); 3529 if (new_index != 0) { 3530 log_trace(redefine, class, constantpool)("field-name_index change: %d to %d", cur_index, new_index); 3531 fi->set_name_index(new_index); 3532 update_required = true; 3533 } 3534 cur_index = fi->signature_index(); 3535 new_index = find_new_index(cur_index); 3536 if (new_index != 0) { 3537 log_trace(redefine, class, constantpool)("field-signature_index change: %d to %d", cur_index, new_index); 3538 fi->set_signature_index(new_index); 3539 update_required = true; 3540 } 3541 cur_index = fi->initializer_index(); 3542 new_index = find_new_index(cur_index); 3543 if (new_index != 0) { 3544 log_trace(redefine, class, constantpool)("field-initval_index change: %d to %d", cur_index, new_index); 3545 fi->set_initializer_index(new_index); 3546 update_required = true; 3547 } 3548 cur_index = fi->generic_signature_index(); 3549 new_index = find_new_index(cur_index); 3550 if (new_index != 0) { 3551 log_trace(redefine, class, constantpool)("field-generic_signature change: %d to %d", cur_index, new_index); 3552 fi->set_generic_signature_index(new_index); 3553 update_required = true; 3554 } 3555 } 3556 if (update_required) { 3557 Array<u1>* old_stream = scratch_class->fieldinfo_stream(); 3558 assert(fields->length() == (java_fields + injected_fields), "Must be"); 3559 Array<u1>* new_fis = FieldInfoStream::create_FieldInfoStream(fields, java_fields, injected_fields, scratch_class->class_loader_data(), CHECK); 3560 scratch_class->set_fieldinfo_stream(new_fis); 3561 MetadataFactory::free_array<u1>(scratch_class->class_loader_data(), old_stream); 3562 } 3563 3564 // Update constant pool indices in the inner classes info to use 3565 // new constant indices as needed. The inner classes info is a 3566 // quadruple: 3567 // (inner_class_info, outer_class_info, inner_name, inner_access_flags) 3568 InnerClassesIterator iter(scratch_class); 3569 for (; !iter.done(); iter.next()) { 3570 int cur_index = iter.inner_class_info_index(); 3571 if (cur_index == 0) { 3572 continue; // JVM spec. allows null inner class refs so skip it 3573 } 3574 u2 new_index = find_new_index(cur_index); 3575 if (new_index != 0) { 3576 log_trace(redefine, class, constantpool)("inner_class_info change: %d to %d", cur_index, new_index); 3577 iter.set_inner_class_info_index(new_index); 3578 } 3579 cur_index = iter.outer_class_info_index(); 3580 new_index = find_new_index(cur_index); 3581 if (new_index != 0) { 3582 log_trace(redefine, class, constantpool)("outer_class_info change: %d to %d", cur_index, new_index); 3583 iter.set_outer_class_info_index(new_index); 3584 } 3585 cur_index = iter.inner_name_index(); 3586 new_index = find_new_index(cur_index); 3587 if (new_index != 0) { 3588 log_trace(redefine, class, constantpool)("inner_name change: %d to %d", cur_index, new_index); 3589 iter.set_inner_name_index(new_index); 3590 } 3591 } // end for each inner class 3592 3593 // Attach each method in klass to the new constant pool and update 3594 // to use new constant pool indices as needed: 3595 Array<Method*>* methods = scratch_class->methods(); 3596 for (i = methods->length() - 1; i >= 0; i--) { 3597 methodHandle method(THREAD, methods->at(i)); 3598 method->set_constants(scratch_cp()); 3599 3600 u2 new_index = find_new_index(method->name_index()); 3601 if (new_index != 0) { 3602 log_trace(redefine, class, constantpool) 3603 ("method-name_index change: %d to %d", method->name_index(), new_index); 3604 method->set_name_index(new_index); 3605 } 3606 new_index = find_new_index(method->signature_index()); 3607 if (new_index != 0) { 3608 log_trace(redefine, class, constantpool) 3609 ("method-signature_index change: %d to %d", method->signature_index(), new_index); 3610 method->set_signature_index(new_index); 3611 } 3612 new_index = find_new_index(method->generic_signature_index()); 3613 if (new_index != 0) { 3614 log_trace(redefine, class, constantpool) 3615 ("method-generic_signature_index change: %d to %d", method->generic_signature_index(), new_index); 3616 method->constMethod()->set_generic_signature_index(new_index); 3617 } 3618 3619 // Update constant pool indices in the method's checked exception 3620 // table to use new constant indices as needed. 3621 int cext_length = method->checked_exceptions_length(); 3622 if (cext_length > 0) { 3623 CheckedExceptionElement * cext_table = 3624 method->checked_exceptions_start(); 3625 for (int j = 0; j < cext_length; j++) { 3626 int cur_index = cext_table[j].class_cp_index; 3627 int new_index = find_new_index(cur_index); 3628 if (new_index != 0) { 3629 log_trace(redefine, class, constantpool)("cext-class_cp_index change: %d to %d", cur_index, new_index); 3630 cext_table[j].class_cp_index = (u2)new_index; 3631 } 3632 } // end for each checked exception table entry 3633 } // end if there are checked exception table entries 3634 3635 // Update each catch type index in the method's exception table 3636 // to use new constant pool indices as needed. The exception table 3637 // holds quadruple entries of the form: 3638 // (beg_bci, end_bci, handler_bci, klass_index) 3639 3640 ExceptionTable ex_table(method()); 3641 int ext_length = ex_table.length(); 3642 3643 for (int j = 0; j < ext_length; j ++) { 3644 int cur_index = ex_table.catch_type_index(j); 3645 u2 new_index = find_new_index(cur_index); 3646 if (new_index != 0) { 3647 log_trace(redefine, class, constantpool)("ext-klass_index change: %d to %d", cur_index, new_index); 3648 ex_table.set_catch_type_index(j, new_index); 3649 } 3650 } // end for each exception table entry 3651 3652 // Update constant pool indices in the method's local variable 3653 // table to use new constant indices as needed. The local variable 3654 // table hold sextuple entries of the form: 3655 // (start_pc, length, name_index, descriptor_index, signature_index, slot) 3656 int lvt_length = method->localvariable_table_length(); 3657 if (lvt_length > 0) { 3658 LocalVariableTableElement * lv_table = 3659 method->localvariable_table_start(); 3660 for (int j = 0; j < lvt_length; j++) { 3661 int cur_index = lv_table[j].name_cp_index; 3662 int new_index = find_new_index(cur_index); 3663 if (new_index != 0) { 3664 log_trace(redefine, class, constantpool)("lvt-name_cp_index change: %d to %d", cur_index, new_index); 3665 lv_table[j].name_cp_index = (u2)new_index; 3666 } 3667 cur_index = lv_table[j].descriptor_cp_index; 3668 new_index = find_new_index(cur_index); 3669 if (new_index != 0) { 3670 log_trace(redefine, class, constantpool)("lvt-descriptor_cp_index change: %d to %d", cur_index, new_index); 3671 lv_table[j].descriptor_cp_index = (u2)new_index; 3672 } 3673 cur_index = lv_table[j].signature_cp_index; 3674 new_index = find_new_index(cur_index); 3675 if (new_index != 0) { 3676 log_trace(redefine, class, constantpool)("lvt-signature_cp_index change: %d to %d", cur_index, new_index); 3677 lv_table[j].signature_cp_index = (u2)new_index; 3678 } 3679 } // end for each local variable table entry 3680 } // end if there are local variable table entries 3681 3682 // Update constant pool indices in the method's method_parameters. 3683 int mp_length = method->method_parameters_length(); 3684 if (mp_length > 0) { 3685 MethodParametersElement* elem = method->method_parameters_start(); 3686 for (int j = 0; j < mp_length; j++) { 3687 const int cp_index = elem[j].name_cp_index; 3688 const int new_cp_index = find_new_index(cp_index); 3689 if (new_cp_index != 0) { 3690 elem[j].name_cp_index = (u2)new_cp_index; 3691 } 3692 } 3693 } 3694 3695 rewrite_cp_refs_in_stack_map_table(method); 3696 } // end for each method 3697 } // end set_new_constant_pool() 3698 3699 3700 // Unevolving classes may point to methods of the_class directly 3701 // from their constant pool caches, itables, and/or vtables. We 3702 // use the ClassLoaderDataGraph::classes_do() facility and this helper 3703 // to fix up these pointers. MethodData also points to old methods and 3704 // must be cleaned. 3705 3706 // Adjust cpools and vtables closure 3707 void VM_RedefineClasses::AdjustAndCleanMetadata::do_klass(Klass* k) { 3708 3709 // This is a very busy routine. We don't want too much tracing 3710 // printed out. 3711 bool trace_name_printed = false; 3712 3713 // If the class being redefined is java.lang.Object, we need to fix all 3714 // array class vtables also. The _has_redefined_Object flag is global. 3715 // Once the java.lang.Object has been redefined (by the current or one 3716 // of the previous VM_RedefineClasses operations) we have to always 3717 // adjust method entries for array classes. 3718 if (k->is_array_klass() && _has_redefined_Object) { 3719 k->vtable().adjust_method_entries(&trace_name_printed); 3720 3721 } else if (k->is_instance_klass()) { 3722 HandleMark hm(_thread); 3723 InstanceKlass *ik = InstanceKlass::cast(k); 3724 3725 // Clean MethodData of this class's methods so they don't refer to 3726 // old methods that are no longer running. 3727 Array<Method*>* methods = ik->methods(); 3728 int num_methods = methods->length(); 3729 for (int index = 0; index < num_methods; ++index) { 3730 if (methods->at(index)->method_data() != nullptr) { 3731 methods->at(index)->method_data()->clean_weak_method_links(); 3732 } 3733 } 3734 3735 // Adjust all vtables, default methods and itables, to clean out old methods. 3736 ResourceMark rm(_thread); 3737 if (ik->vtable_length() > 0) { 3738 ik->vtable().adjust_method_entries(&trace_name_printed); 3739 ik->adjust_default_methods(&trace_name_printed); 3740 } 3741 3742 if (ik->itable_length() > 0) { 3743 ik->itable().adjust_method_entries(&trace_name_printed); 3744 } 3745 3746 // The constant pools in other classes (other_cp) can refer to 3747 // old methods. We have to update method information in 3748 // other_cp's cache. If other_cp has a previous version, then we 3749 // have to repeat the process for each previous version. The 3750 // constant pool cache holds the Method*s for non-virtual 3751 // methods and for virtual, final methods. 3752 // 3753 // Special case: if the current class is being redefined by the current 3754 // VM_RedefineClasses operation, then new_cp has already been attached 3755 // to the_class and old_cp has already been added as a previous version. 3756 // The new_cp doesn't have any cached references to old methods so it 3757 // doesn't need to be updated and we could optimize by skipping it. 3758 // However, the current class can be marked as being redefined by another 3759 // VM_RedefineClasses operation which has already executed its doit_prologue 3760 // and needs cpcache method entries adjusted. For simplicity, the cpcache 3761 // update is done unconditionally. It should result in doing nothing for 3762 // classes being redefined by the current VM_RedefineClasses operation. 3763 // Method entries in the previous version(s) are adjusted as well. 3764 ConstantPoolCache* cp_cache; 3765 3766 // this klass' constant pool cache may need adjustment 3767 ConstantPool* other_cp = ik->constants(); 3768 cp_cache = other_cp->cache(); 3769 if (cp_cache != nullptr) { 3770 cp_cache->adjust_method_entries(&trace_name_printed); 3771 } 3772 3773 // the previous versions' constant pool caches may need adjustment 3774 for (InstanceKlass* pv_node = ik->previous_versions(); 3775 pv_node != nullptr; 3776 pv_node = pv_node->previous_versions()) { 3777 cp_cache = pv_node->constants()->cache(); 3778 if (cp_cache != nullptr) { 3779 cp_cache->adjust_method_entries(&trace_name_printed); 3780 } 3781 } 3782 } 3783 } 3784 3785 void VM_RedefineClasses::update_jmethod_ids() { 3786 for (int j = 0; j < _matching_methods_length; ++j) { 3787 Method* old_method = _matching_old_methods[j]; 3788 jmethodID jmid = old_method->find_jmethod_id_or_null(); 3789 if (jmid != nullptr) { 3790 // There is a jmethodID, change it to point to the new method 3791 Method* new_method = _matching_new_methods[j]; 3792 Method::change_method_associated_with_jmethod_id(jmid, new_method); 3793 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j], 3794 "should be replaced"); 3795 } 3796 } 3797 } 3798 3799 int VM_RedefineClasses::check_methods_and_mark_as_obsolete() { 3800 int emcp_method_count = 0; 3801 int obsolete_count = 0; 3802 int old_index = 0; 3803 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) { 3804 Method* old_method = _matching_old_methods[j]; 3805 Method* new_method = _matching_new_methods[j]; 3806 Method* old_array_method; 3807 3808 // Maintain an old_index into the _old_methods array by skipping 3809 // deleted methods 3810 while ((old_array_method = _old_methods->at(old_index)) != old_method) { 3811 ++old_index; 3812 } 3813 3814 if (MethodComparator::methods_EMCP(old_method, new_method)) { 3815 // The EMCP definition from JSR-163 requires the bytecodes to be 3816 // the same with the exception of constant pool indices which may 3817 // differ. However, the constants referred to by those indices 3818 // must be the same. 3819 // 3820 // We use methods_EMCP() for comparison since constant pool 3821 // merging can remove duplicate constant pool entries that were 3822 // present in the old method and removed from the rewritten new 3823 // method. A faster binary comparison function would consider the 3824 // old and new methods to be different when they are actually 3825 // EMCP. 3826 // 3827 // The old and new methods are EMCP and you would think that we 3828 // could get rid of one of them here and now and save some space. 3829 // However, the concept of EMCP only considers the bytecodes and 3830 // the constant pool entries in the comparison. Other things, 3831 // e.g., the line number table (LNT) or the local variable table 3832 // (LVT) don't count in the comparison. So the new (and EMCP) 3833 // method can have a new LNT that we need so we can't just 3834 // overwrite the new method with the old method. 3835 // 3836 // When this routine is called, we have already attached the new 3837 // methods to the_class so the old methods are effectively 3838 // overwritten. However, if an old method is still executing, 3839 // then the old method cannot be collected until sometime after 3840 // the old method call has returned. So the overwriting of old 3841 // methods by new methods will save us space except for those 3842 // (hopefully few) old methods that are still executing. 3843 // 3844 // A method refers to a ConstMethod* and this presents another 3845 // possible avenue to space savings. The ConstMethod* in the 3846 // new method contains possibly new attributes (LNT, LVT, etc). 3847 // At first glance, it seems possible to save space by replacing 3848 // the ConstMethod* in the old method with the ConstMethod* 3849 // from the new method. The old and new methods would share the 3850 // same ConstMethod* and we would save the space occupied by 3851 // the old ConstMethod*. However, the ConstMethod* contains 3852 // a back reference to the containing method. Sharing the 3853 // ConstMethod* between two methods could lead to confusion in 3854 // the code that uses the back reference. This would lead to 3855 // brittle code that could be broken in non-obvious ways now or 3856 // in the future. 3857 // 3858 // Another possibility is to copy the ConstMethod* from the new 3859 // method to the old method and then overwrite the new method with 3860 // the old method. Since the ConstMethod* contains the bytecodes 3861 // for the method embedded in the oop, this option would change 3862 // the bytecodes out from under any threads executing the old 3863 // method and make the thread's bcp invalid. Since EMCP requires 3864 // that the bytecodes be the same modulo constant pool indices, it 3865 // is straight forward to compute the correct new bcp in the new 3866 // ConstMethod* from the old bcp in the old ConstMethod*. The 3867 // time consuming part would be searching all the frames in all 3868 // of the threads to find all of the calls to the old method. 3869 // 3870 // It looks like we will have to live with the limited savings 3871 // that we get from effectively overwriting the old methods 3872 // when the new methods are attached to the_class. 3873 3874 // Count number of methods that are EMCP. The method will be marked 3875 // old but not obsolete if it is EMCP. 3876 emcp_method_count++; 3877 3878 // An EMCP method is _not_ obsolete. An obsolete method has a 3879 // different jmethodID than the current method. An EMCP method 3880 // has the same jmethodID as the current method. Having the 3881 // same jmethodID for all EMCP versions of a method allows for 3882 // a consistent view of the EMCP methods regardless of which 3883 // EMCP method you happen to have in hand. For example, a 3884 // breakpoint set in one EMCP method will work for all EMCP 3885 // versions of the method including the current one. 3886 } else { 3887 // mark obsolete methods as such 3888 old_method->set_is_obsolete(); 3889 obsolete_count++; 3890 3891 // obsolete methods need a unique idnum so they become new entries in 3892 // the jmethodID cache in InstanceKlass 3893 assert(old_method->method_idnum() == new_method->method_idnum(), "must match"); 3894 u2 num = InstanceKlass::cast(_the_class)->next_method_idnum(); 3895 if (num != ConstMethod::UNSET_IDNUM) { 3896 old_method->set_method_idnum(num); 3897 } 3898 3899 // With tracing we try not to "yack" too much. The position of 3900 // this trace assumes there are fewer obsolete methods than 3901 // EMCP methods. 3902 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) { 3903 ResourceMark rm; 3904 log_trace(redefine, class, obsolete, mark) 3905 ("mark %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string()); 3906 } 3907 } 3908 old_method->set_is_old(); 3909 } 3910 for (int i = 0; i < _deleted_methods_length; ++i) { 3911 Method* old_method = _deleted_methods[i]; 3912 3913 assert(!old_method->has_vtable_index(), 3914 "cannot delete methods with vtable entries");; 3915 3916 // Mark all deleted methods as old, obsolete and deleted 3917 old_method->set_is_deleted(); 3918 old_method->set_is_old(); 3919 old_method->set_is_obsolete(); 3920 ++obsolete_count; 3921 // With tracing we try not to "yack" too much. The position of 3922 // this trace assumes there are fewer obsolete methods than 3923 // EMCP methods. 3924 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) { 3925 ResourceMark rm; 3926 log_trace(redefine, class, obsolete, mark) 3927 ("mark deleted %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string()); 3928 } 3929 } 3930 assert((emcp_method_count + obsolete_count) == _old_methods->length(), 3931 "sanity check"); 3932 log_trace(redefine, class, obsolete, mark)("EMCP_cnt=%d, obsolete_cnt=%d", emcp_method_count, obsolete_count); 3933 return emcp_method_count; 3934 } 3935 3936 // This internal class transfers the native function registration from old methods 3937 // to new methods. It is designed to handle both the simple case of unchanged 3938 // native methods and the complex cases of native method prefixes being added and/or 3939 // removed. 3940 // It expects only to be used during the VM_RedefineClasses op (a safepoint). 3941 // 3942 // This class is used after the new methods have been installed in "the_class". 3943 // 3944 // So, for example, the following must be handled. Where 'm' is a method and 3945 // a number followed by an underscore is a prefix. 3946 // 3947 // Old Name New Name 3948 // Simple transfer to new method m -> m 3949 // Add prefix m -> 1_m 3950 // Remove prefix 1_m -> m 3951 // Simultaneous add of prefixes m -> 3_2_1_m 3952 // Simultaneous removal of prefixes 3_2_1_m -> m 3953 // Simultaneous add and remove 1_m -> 2_m 3954 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m 3955 // 3956 class TransferNativeFunctionRegistration { 3957 private: 3958 InstanceKlass* the_class; 3959 int prefix_count; 3960 char** prefixes; 3961 3962 // Recursively search the binary tree of possibly prefixed method names. 3963 // Iteration could be used if all agents were well behaved. Full tree walk is 3964 // more resilent to agents not cleaning up intermediate methods. 3965 // Branch at each depth in the binary tree is: 3966 // (1) without the prefix. 3967 // (2) with the prefix. 3968 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...) 3969 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len, 3970 Symbol* signature) { 3971 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len); 3972 if (name_symbol != nullptr) { 3973 Method* method = the_class->lookup_method(name_symbol, signature); 3974 if (method != nullptr) { 3975 // Even if prefixed, intermediate methods must exist. 3976 if (method->is_native()) { 3977 // Wahoo, we found a (possibly prefixed) version of the method, return it. 3978 return method; 3979 } 3980 if (depth < prefix_count) { 3981 // Try applying further prefixes (other than this one). 3982 method = search_prefix_name_space(depth+1, name_str, name_len, signature); 3983 if (method != nullptr) { 3984 return method; // found 3985 } 3986 3987 // Try adding this prefix to the method name and see if it matches 3988 // another method name. 3989 char* prefix = prefixes[depth]; 3990 size_t prefix_len = strlen(prefix); 3991 size_t trial_len = name_len + prefix_len; 3992 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1); 3993 strcpy(trial_name_str, prefix); 3994 strcat(trial_name_str, name_str); 3995 method = search_prefix_name_space(depth+1, trial_name_str, trial_len, 3996 signature); 3997 if (method != nullptr) { 3998 // If found along this branch, it was prefixed, mark as such 3999 method->set_is_prefixed_native(); 4000 return method; // found 4001 } 4002 } 4003 } 4004 } 4005 return nullptr; // This whole branch bore nothing 4006 } 4007 4008 // Return the method name with old prefixes stripped away. 4009 char* method_name_without_prefixes(Method* method) { 4010 Symbol* name = method->name(); 4011 char* name_str = name->as_utf8(); 4012 4013 // Old prefixing may be defunct, strip prefixes, if any. 4014 for (int i = prefix_count-1; i >= 0; i--) { 4015 char* prefix = prefixes[i]; 4016 size_t prefix_len = strlen(prefix); 4017 if (strncmp(prefix, name_str, prefix_len) == 0) { 4018 name_str += prefix_len; 4019 } 4020 } 4021 return name_str; 4022 } 4023 4024 // Strip any prefixes off the old native method, then try to find a 4025 // (possibly prefixed) new native that matches it. 4026 Method* strip_and_search_for_new_native(Method* method) { 4027 ResourceMark rm; 4028 char* name_str = method_name_without_prefixes(method); 4029 return search_prefix_name_space(0, name_str, strlen(name_str), 4030 method->signature()); 4031 } 4032 4033 public: 4034 4035 // Construct a native method transfer processor for this class. 4036 TransferNativeFunctionRegistration(InstanceKlass* _the_class) { 4037 assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); 4038 4039 the_class = _the_class; 4040 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count); 4041 } 4042 4043 // Attempt to transfer any of the old or deleted methods that are native 4044 void transfer_registrations(Method** old_methods, int methods_length) { 4045 for (int j = 0; j < methods_length; j++) { 4046 Method* old_method = old_methods[j]; 4047 4048 if (old_method->is_native() && old_method->has_native_function()) { 4049 Method* new_method = strip_and_search_for_new_native(old_method); 4050 if (new_method != nullptr) { 4051 // Actually set the native function in the new method. 4052 // Redefine does not send events (except CFLH), certainly not this 4053 // behind the scenes re-registration. 4054 new_method->set_native_function(old_method->native_function(), 4055 !Method::native_bind_event_is_interesting); 4056 } 4057 } 4058 } 4059 } 4060 }; 4061 4062 // Don't lose the association between a native method and its JNI function. 4063 void VM_RedefineClasses::transfer_old_native_function_registrations(InstanceKlass* the_class) { 4064 TransferNativeFunctionRegistration transfer(the_class); 4065 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length); 4066 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length); 4067 } 4068 4069 // Deoptimize all compiled code that depends on the classes redefined. 4070 // 4071 // If the can_redefine_classes capability is obtained in the onload 4072 // phase or 'AlwaysRecordEvolDependencies' is true, then the compiler has 4073 // recorded all dependencies from startup. In that case we need only 4074 // deoptimize and throw away all compiled code that depends on the class. 4075 // 4076 // If can_redefine_classes is obtained sometime after the onload phase 4077 // (and 'AlwaysRecordEvolDependencies' is false) then the dependency 4078 // information may be incomplete. In that case the first call to 4079 // RedefineClasses causes all compiled code to be thrown away. As 4080 // can_redefine_classes has been obtained then all future compilations will 4081 // record dependencies so second and subsequent calls to RedefineClasses 4082 // need only throw away code that depends on the class. 4083 // 4084 4085 void VM_RedefineClasses::flush_dependent_code() { 4086 assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); 4087 assert(JvmtiExport::all_dependencies_are_recorded() || !AlwaysRecordEvolDependencies, "sanity check"); 4088 4089 DeoptimizationScope deopt_scope; 4090 4091 // This is the first redefinition, mark all the nmethods for deoptimization 4092 if (!JvmtiExport::all_dependencies_are_recorded()) { 4093 CodeCache::mark_all_nmethods_for_evol_deoptimization(&deopt_scope); 4094 log_debug(redefine, class, nmethod)("Marked all nmethods for deopt"); 4095 } else { 4096 CodeCache::mark_dependents_for_evol_deoptimization(&deopt_scope); 4097 log_debug(redefine, class, nmethod)("Marked dependent nmethods for deopt"); 4098 } 4099 4100 deopt_scope.deoptimize_marked(); 4101 4102 // From now on we know that the dependency information is complete 4103 JvmtiExport::set_all_dependencies_are_recorded(true); 4104 } 4105 4106 void VM_RedefineClasses::compute_added_deleted_matching_methods() { 4107 Method* old_method; 4108 Method* new_method; 4109 4110 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 4111 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 4112 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length()); 4113 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 4114 4115 _matching_methods_length = 0; 4116 _deleted_methods_length = 0; 4117 _added_methods_length = 0; 4118 4119 int nj = 0; 4120 int oj = 0; 4121 while (true) { 4122 if (oj >= _old_methods->length()) { 4123 if (nj >= _new_methods->length()) { 4124 break; // we've looked at everything, done 4125 } 4126 // New method at the end 4127 new_method = _new_methods->at(nj); 4128 _added_methods[_added_methods_length++] = new_method; 4129 ++nj; 4130 } else if (nj >= _new_methods->length()) { 4131 // Old method, at the end, is deleted 4132 old_method = _old_methods->at(oj); 4133 _deleted_methods[_deleted_methods_length++] = old_method; 4134 ++oj; 4135 } else { 4136 old_method = _old_methods->at(oj); 4137 new_method = _new_methods->at(nj); 4138 if (old_method->name() == new_method->name()) { 4139 if (old_method->signature() == new_method->signature()) { 4140 _matching_old_methods[_matching_methods_length ] = old_method; 4141 _matching_new_methods[_matching_methods_length++] = new_method; 4142 ++nj; 4143 ++oj; 4144 } else { 4145 // added overloaded have already been moved to the end, 4146 // so this is a deleted overloaded method 4147 _deleted_methods[_deleted_methods_length++] = old_method; 4148 ++oj; 4149 } 4150 } else { // names don't match 4151 if (old_method->name()->fast_compare(new_method->name()) > 0) { 4152 // new method 4153 _added_methods[_added_methods_length++] = new_method; 4154 ++nj; 4155 } else { 4156 // deleted method 4157 _deleted_methods[_deleted_methods_length++] = old_method; 4158 ++oj; 4159 } 4160 } 4161 } 4162 } 4163 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity"); 4164 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity"); 4165 } 4166 4167 4168 void VM_RedefineClasses::swap_annotations(InstanceKlass* the_class, 4169 InstanceKlass* scratch_class) { 4170 // Swap annotation fields values 4171 Annotations* old_annotations = the_class->annotations(); 4172 the_class->set_annotations(scratch_class->annotations()); 4173 scratch_class->set_annotations(old_annotations); 4174 } 4175 4176 4177 // Install the redefinition of a class: 4178 // - house keeping (flushing breakpoints and caches, deoptimizing 4179 // dependent compiled code) 4180 // - replacing parts in the_class with parts from scratch_class 4181 // - adding a weak reference to track the obsolete but interesting 4182 // parts of the_class 4183 // - adjusting constant pool caches and vtables in other classes 4184 // that refer to methods in the_class. These adjustments use the 4185 // ClassLoaderDataGraph::classes_do() facility which only allows 4186 // a helper method to be specified. The interesting parameters 4187 // that we would like to pass to the helper method are saved in 4188 // static global fields in the VM operation. 4189 void VM_RedefineClasses::redefine_single_class(Thread* current, jclass the_jclass, 4190 InstanceKlass* scratch_class) { 4191 4192 HandleMark hm(current); // make sure handles from this call are freed 4193 4194 if (log_is_enabled(Info, redefine, class, timer)) { 4195 _timer_rsc_phase1.start(); 4196 } 4197 4198 InstanceKlass* the_class = get_ik(the_jclass); 4199 4200 // Set a flag to control and optimize adjusting method entries 4201 _has_redefined_Object |= the_class == vmClasses::Object_klass(); 4202 4203 // Remove all breakpoints in methods of this class 4204 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints(); 4205 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class); 4206 4207 _old_methods = the_class->methods(); 4208 _new_methods = scratch_class->methods(); 4209 _the_class = the_class; 4210 compute_added_deleted_matching_methods(); 4211 update_jmethod_ids(); 4212 4213 _any_class_has_resolved_methods = the_class->has_resolved_methods() || _any_class_has_resolved_methods; 4214 4215 // Attach new constant pool to the original klass. The original 4216 // klass still refers to the old constant pool (for now). 4217 scratch_class->constants()->set_pool_holder(the_class); 4218 4219 #if 0 4220 // In theory, with constant pool merging in place we should be able 4221 // to save space by using the new, merged constant pool in place of 4222 // the old constant pool(s). By "pool(s)" I mean the constant pool in 4223 // the klass version we are replacing now and any constant pool(s) in 4224 // previous versions of klass. Nice theory, doesn't work in practice. 4225 // When this code is enabled, even simple programs throw NullPointer 4226 // exceptions. I'm guessing that this is caused by some constant pool 4227 // cache difference between the new, merged constant pool and the 4228 // constant pool that was just being used by the klass. I'm keeping 4229 // this code around to archive the idea, but the code has to remain 4230 // disabled for now. 4231 4232 // Attach each old method to the new constant pool. This can be 4233 // done here since we are past the bytecode verification and 4234 // constant pool optimization phases. 4235 for (int i = _old_methods->length() - 1; i >= 0; i--) { 4236 Method* method = _old_methods->at(i); 4237 method->set_constants(scratch_class->constants()); 4238 } 4239 4240 // NOTE: this doesn't work because you can redefine the same class in two 4241 // threads, each getting their own constant pool data appended to the 4242 // original constant pool. In order for the new methods to work when they 4243 // become old methods, they need to keep their updated copy of the constant pool. 4244 4245 { 4246 // walk all previous versions of the klass 4247 InstanceKlass *ik = the_class; 4248 PreviousVersionWalker pvw(ik); 4249 do { 4250 ik = pvw.next_previous_version(); 4251 if (ik != nullptr) { 4252 4253 // attach previous version of klass to the new constant pool 4254 ik->set_constants(scratch_class->constants()); 4255 4256 // Attach each method in the previous version of klass to the 4257 // new constant pool 4258 Array<Method*>* prev_methods = ik->methods(); 4259 for (int i = prev_methods->length() - 1; i >= 0; i--) { 4260 Method* method = prev_methods->at(i); 4261 method->set_constants(scratch_class->constants()); 4262 } 4263 } 4264 } while (ik != nullptr); 4265 } 4266 #endif 4267 4268 // Replace methods and constantpool 4269 the_class->set_methods(_new_methods); 4270 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods, 4271 // and to be able to undo operation easily. 4272 4273 Array<int>* old_ordering = the_class->method_ordering(); 4274 the_class->set_method_ordering(scratch_class->method_ordering()); 4275 scratch_class->set_method_ordering(old_ordering); 4276 4277 ConstantPool* old_constants = the_class->constants(); 4278 the_class->set_constants(scratch_class->constants()); 4279 scratch_class->set_constants(old_constants); // See the previous comment. 4280 #if 0 4281 // We are swapping the guts of "the new class" with the guts of "the 4282 // class". Since the old constant pool has just been attached to "the 4283 // new class", it seems logical to set the pool holder in the old 4284 // constant pool also. However, doing this will change the observable 4285 // class hierarchy for any old methods that are still executing. A 4286 // method can query the identity of its "holder" and this query uses 4287 // the method's constant pool link to find the holder. The change in 4288 // holding class from "the class" to "the new class" can confuse 4289 // things. 4290 // 4291 // Setting the old constant pool's holder will also cause 4292 // verification done during vtable initialization below to fail. 4293 // During vtable initialization, the vtable's class is verified to be 4294 // a subtype of the method's holder. The vtable's class is "the 4295 // class" and the method's holder is gotten from the constant pool 4296 // link in the method itself. For "the class"'s directly implemented 4297 // methods, the method holder is "the class" itself (as gotten from 4298 // the new constant pool). The check works fine in this case. The 4299 // check also works fine for methods inherited from super classes. 4300 // 4301 // Miranda methods are a little more complicated. A miranda method is 4302 // provided by an interface when the class implementing the interface 4303 // does not provide its own method. These interfaces are implemented 4304 // internally as an InstanceKlass. These special instanceKlasses 4305 // share the constant pool of the class that "implements" the 4306 // interface. By sharing the constant pool, the method holder of a 4307 // miranda method is the class that "implements" the interface. In a 4308 // non-redefine situation, the subtype check works fine. However, if 4309 // the old constant pool's pool holder is modified, then the check 4310 // fails because there is no class hierarchy relationship between the 4311 // vtable's class and "the new class". 4312 4313 old_constants->set_pool_holder(scratch_class()); 4314 #endif 4315 4316 // track number of methods that are EMCP for add_previous_version() call below 4317 int emcp_method_count = check_methods_and_mark_as_obsolete(); 4318 transfer_old_native_function_registrations(the_class); 4319 4320 if (scratch_class->get_cached_class_file() != the_class->get_cached_class_file()) { 4321 // 1. the_class doesn't have a cache yet, scratch_class does have a cache. 4322 // 2. The same class can be present twice in the scratch classes list or there 4323 // are multiple concurrent RetransformClasses calls on different threads. 4324 // the_class and scratch_class have the same cached bytes, but different buffers. 4325 // In such cases we need to deallocate one of the buffers. 4326 // 3. RedefineClasses and the_class has cached bytes from a previous transformation. 4327 // In the case we need to use class bytes from scratch_class. 4328 if (the_class->get_cached_class_file() != nullptr) { 4329 os::free(the_class->get_cached_class_file()); 4330 } 4331 the_class->set_cached_class_file(scratch_class->get_cached_class_file()); 4332 } 4333 4334 // null out in scratch class to not delete twice. The class to be redefined 4335 // always owns these bytes. 4336 scratch_class->set_cached_class_file(nullptr); 4337 4338 // Replace inner_classes 4339 Array<u2>* old_inner_classes = the_class->inner_classes(); 4340 the_class->set_inner_classes(scratch_class->inner_classes()); 4341 scratch_class->set_inner_classes(old_inner_classes); 4342 4343 // Initialize the vtable and interface table after 4344 // methods have been rewritten 4345 // no exception should happen here since we explicitly 4346 // do not check loader constraints. 4347 // compare_and_normalize_class_versions has already checked: 4348 // - classloaders unchanged, signatures unchanged 4349 // - all instanceKlasses for redefined classes reused & contents updated 4350 the_class->vtable().initialize_vtable(); 4351 the_class->itable().initialize_itable(); 4352 4353 // Leave arrays of jmethodIDs and itable index cache unchanged 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 }