1 /* 2 * Copyright (c) 2003, 2025, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "cds/cdsConfig.hpp" 26 #include "cds/metaspaceShared.hpp" 27 #include "classfile/classFileStream.hpp" 28 #include "classfile/classLoaderDataGraph.hpp" 29 #include "classfile/classLoadInfo.hpp" 30 #include "classfile/javaClasses.inline.hpp" 31 #include "classfile/klassFactory.hpp" 32 #include "classfile/metadataOnStackMark.hpp" 33 #include "classfile/stackMapTable.hpp" 34 #include "classfile/symbolTable.hpp" 35 #include "classfile/verifier.hpp" 36 #include "classfile/vmClasses.hpp" 37 #include "classfile/vmSymbols.hpp" 38 #include "code/codeCache.hpp" 39 #include "compiler/compileBroker.hpp" 40 #include "interpreter/oopMapCache.hpp" 41 #include "interpreter/rewriter.hpp" 42 #include "jfr/jfrEvents.hpp" 43 #include "logging/logStream.hpp" 44 #include "memory/metadataFactory.hpp" 45 #include "memory/resourceArea.hpp" 46 #include "memory/universe.hpp" 47 #include "oops/annotations.hpp" 48 #include "oops/constantPool.hpp" 49 #include "oops/fieldStreams.inline.hpp" 50 #include "oops/klass.inline.hpp" 51 #include "oops/klassVtable.hpp" 52 #include "oops/method.hpp" 53 #include "oops/oop.inline.hpp" 54 #include "oops/recordComponent.hpp" 55 #include "prims/jvmtiImpl.hpp" 56 #include "prims/jvmtiRedefineClasses.hpp" 57 #include "prims/jvmtiThreadState.inline.hpp" 58 #include "prims/resolvedMethodTable.hpp" 59 #include "prims/methodComparator.hpp" 60 #include "runtime/atomic.hpp" 61 #include "runtime/deoptimization.hpp" 62 #include "runtime/handles.inline.hpp" 63 #include "runtime/jniHandles.inline.hpp" 64 #include "runtime/relocator.hpp" 65 #include "runtime/safepointVerifiers.hpp" 66 #include "utilities/bitMap.inline.hpp" 67 #include "utilities/checkedCast.hpp" 68 #include "utilities/events.hpp" 69 #include "utilities/macros.hpp" 70 71 Array<Method*>* VM_RedefineClasses::_old_methods = nullptr; 72 Array<Method*>* VM_RedefineClasses::_new_methods = nullptr; 73 Method** VM_RedefineClasses::_matching_old_methods = nullptr; 74 Method** VM_RedefineClasses::_matching_new_methods = nullptr; 75 Method** VM_RedefineClasses::_deleted_methods = nullptr; 76 Method** VM_RedefineClasses::_added_methods = nullptr; 77 int VM_RedefineClasses::_matching_methods_length = 0; 78 int VM_RedefineClasses::_deleted_methods_length = 0; 79 int VM_RedefineClasses::_added_methods_length = 0; 80 81 // This flag is global as the constructor does not reset it: 82 bool VM_RedefineClasses::_has_redefined_Object = false; 83 u8 VM_RedefineClasses::_id_counter = 0; 84 85 VM_RedefineClasses::VM_RedefineClasses(jint class_count, 86 const jvmtiClassDefinition *class_defs, 87 JvmtiClassLoadKind class_load_kind) { 88 _class_count = class_count; 89 _class_defs = class_defs; 90 _class_load_kind = class_load_kind; 91 _any_class_has_resolved_methods = false; 92 _res = JVMTI_ERROR_NONE; 93 _the_class = nullptr; 94 _id = next_id(); 95 } 96 97 static inline InstanceKlass* get_ik(jclass def) { 98 oop mirror = JNIHandles::resolve_non_null(def); 99 return InstanceKlass::cast(java_lang_Class::as_Klass(mirror)); 100 } 101 102 // If any of the classes are being redefined, wait 103 // Parallel constant pool merging leads to indeterminate constant pools. 104 void VM_RedefineClasses::lock_classes() { 105 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current()); 106 GrowableArray<Klass*>* redef_classes = state->get_classes_being_redefined(); 107 108 MonitorLocker ml(RedefineClasses_lock); 109 110 if (redef_classes == nullptr) { 111 redef_classes = new (mtClass) GrowableArray<Klass*>(1, mtClass); 112 state->set_classes_being_redefined(redef_classes); 113 } 114 115 bool has_redefined; 116 do { 117 has_redefined = false; 118 // Go through classes each time until none are being redefined. Skip 119 // the ones that are being redefined by this thread currently. Class file 120 // load hook event may trigger new class redefine when we are redefining 121 // a class (after lock_classes()). 122 for (int i = 0; i < _class_count; i++) { 123 InstanceKlass* ik = get_ik(_class_defs[i].klass); 124 // Check if we are currently redefining the class in this thread already. 125 if (redef_classes->contains(ik)) { 126 assert(ik->is_being_redefined(), "sanity"); 127 } else { 128 if (ik->is_being_redefined()) { 129 ml.wait(); 130 has_redefined = true; 131 break; // for loop 132 } 133 } 134 } 135 } while (has_redefined); 136 137 for (int i = 0; i < _class_count; i++) { 138 InstanceKlass* ik = get_ik(_class_defs[i].klass); 139 redef_classes->push(ik); // Add to the _classes_being_redefined list 140 ik->set_is_being_redefined(true); 141 } 142 ml.notify_all(); 143 } 144 145 void VM_RedefineClasses::unlock_classes() { 146 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current()); 147 GrowableArray<Klass*>* redef_classes = state->get_classes_being_redefined(); 148 assert(redef_classes != nullptr, "_classes_being_redefined is not allocated"); 149 150 MonitorLocker ml(RedefineClasses_lock); 151 152 for (int i = _class_count - 1; i >= 0; i--) { 153 InstanceKlass* def_ik = get_ik(_class_defs[i].klass); 154 if (redef_classes->length() > 0) { 155 // Remove the class from _classes_being_redefined list 156 Klass* k = redef_classes->pop(); 157 assert(def_ik == k, "unlocking wrong class"); 158 } 159 assert(def_ik->is_being_redefined(), 160 "should be being redefined to get here"); 161 162 // Unlock after we finish all redefines for this class within 163 // the thread. Same class can be pushed to the list multiple 164 // times (not more than once by each recursive redefinition). 165 if (!redef_classes->contains(def_ik)) { 166 def_ik->set_is_being_redefined(false); 167 } 168 } 169 ml.notify_all(); 170 } 171 172 bool VM_RedefineClasses::doit_prologue() { 173 if (_class_count == 0) { 174 _res = JVMTI_ERROR_NONE; 175 return false; 176 } 177 if (_class_defs == nullptr) { 178 _res = JVMTI_ERROR_NULL_POINTER; 179 return false; 180 } 181 182 for (int i = 0; i < _class_count; i++) { 183 if (_class_defs[i].klass == nullptr) { 184 _res = JVMTI_ERROR_INVALID_CLASS; 185 return false; 186 } 187 if (_class_defs[i].class_byte_count == 0) { 188 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT; 189 return false; 190 } 191 if (_class_defs[i].class_bytes == nullptr) { 192 _res = JVMTI_ERROR_NULL_POINTER; 193 return false; 194 } 195 196 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass); 197 // classes for primitives, arrays, and hidden classes 198 // cannot be redefined. 199 if (!is_modifiable_class(mirror)) { 200 _res = JVMTI_ERROR_UNMODIFIABLE_CLASS; 201 return false; 202 } 203 } 204 205 // Start timer after all the sanity checks; not quite accurate, but 206 // better than adding a bunch of stop() calls. 207 if (log_is_enabled(Info, redefine, class, timer)) { 208 _timer_vm_op_prologue.start(); 209 } 210 211 lock_classes(); 212 // We first load new class versions in the prologue, because somewhere down the 213 // call chain it is required that the current thread is a Java thread. 214 _res = load_new_class_versions(); 215 if (_res != JVMTI_ERROR_NONE) { 216 // free any successfully created classes, since none are redefined 217 for (int i = 0; i < _class_count; i++) { 218 if (_scratch_classes[i] != nullptr) { 219 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data(); 220 // Free the memory for this class at class unloading time. Not before 221 // because CMS might think this is still live. 222 InstanceKlass* ik = get_ik(_class_defs[i].klass); 223 if (ik->get_cached_class_file() == _scratch_classes[i]->get_cached_class_file()) { 224 // Don't double-free cached_class_file copied from the original class if error. 225 _scratch_classes[i]->set_cached_class_file(nullptr); 226 } 227 cld->add_to_deallocate_list(InstanceKlass::cast(_scratch_classes[i])); 228 } 229 } 230 // Free os::malloc allocated memory in load_new_class_version. 231 os::free(_scratch_classes); 232 _timer_vm_op_prologue.stop(); 233 unlock_classes(); 234 return false; 235 } 236 237 _timer_vm_op_prologue.stop(); 238 return true; 239 } 240 241 void VM_RedefineClasses::doit() { 242 Thread* current = Thread::current(); 243 244 if (log_is_enabled(Info, redefine, class, timer)) { 245 _timer_vm_op_doit.start(); 246 } 247 248 #if INCLUDE_CDS 249 if (CDSConfig::is_using_archive()) { 250 // Sharing is enabled so we remap the shared readonly space to 251 // shared readwrite, private just in case we need to redefine 252 // a shared class. We do the remap during the doit() phase of 253 // the safepoint to be safer. 254 if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) { 255 log_info(redefine, class, load)("failed to remap shared readonly space to readwrite, private"); 256 _res = JVMTI_ERROR_INTERNAL; 257 _timer_vm_op_doit.stop(); 258 return; 259 } 260 } 261 #endif 262 263 // Mark methods seen on stack and everywhere else so old methods are not 264 // cleaned up if they're on the stack. 265 MetadataOnStackMark md_on_stack(/*walk_all_metadata*/true, /*redefinition_walk*/true); 266 HandleMark hm(current); // make sure any handles created are deleted 267 // before the stack walk again. 268 269 for (int i = 0; i < _class_count; i++) { 270 redefine_single_class(current, _class_defs[i].klass, _scratch_classes[i]); 271 } 272 273 // Flush all compiled code that depends on the classes redefined. 274 flush_dependent_code(); 275 276 // Adjust constantpool caches and vtables for all classes 277 // that reference methods of the evolved classes. 278 // Have to do this after all classes are redefined and all methods that 279 // are redefined are marked as old. 280 AdjustAndCleanMetadata adjust_and_clean_metadata(current); 281 ClassLoaderDataGraph::classes_do(&adjust_and_clean_metadata); 282 283 // JSR-292 support 284 if (_any_class_has_resolved_methods) { 285 bool trace_name_printed = false; 286 ResolvedMethodTable::adjust_method_entries(&trace_name_printed); 287 } 288 289 // Increment flag indicating that some invariants are no longer true. 290 // See jvmtiExport.hpp for detailed explanation. 291 JvmtiExport::increment_redefinition_count(); 292 293 // check_class() is optionally called for product bits, but is 294 // always called for non-product bits. 295 #ifdef PRODUCT 296 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 297 #endif 298 log_trace(redefine, class, obsolete, metadata)("calling check_class"); 299 CheckClass check_class(current); 300 ClassLoaderDataGraph::classes_do(&check_class); 301 #ifdef PRODUCT 302 } 303 #endif 304 305 // Clean up any metadata now unreferenced while MetadataOnStackMark is set. 306 ClassLoaderDataGraph::clean_deallocate_lists(false); 307 308 _timer_vm_op_doit.stop(); 309 } 310 311 void VM_RedefineClasses::doit_epilogue() { 312 unlock_classes(); 313 314 // Free os::malloc allocated memory. 315 os::free(_scratch_classes); 316 317 // Reset the_class to null for error printing. 318 _the_class = nullptr; 319 320 if (log_is_enabled(Info, redefine, class, timer)) { 321 // Used to have separate timers for "doit" and "all", but the timer 322 // overhead skewed the measurements. 323 julong doit_time = _timer_vm_op_doit.milliseconds(); 324 julong all_time = _timer_vm_op_prologue.milliseconds() + doit_time; 325 326 log_info(redefine, class, timer) 327 ("vm_op: all=" JULONG_FORMAT " prologue=" JULONG_FORMAT " doit=" JULONG_FORMAT, 328 all_time, (julong)_timer_vm_op_prologue.milliseconds(), doit_time); 329 log_info(redefine, class, timer) 330 ("redefine_single_class: phase1=" JULONG_FORMAT " phase2=" JULONG_FORMAT, 331 (julong)_timer_rsc_phase1.milliseconds(), (julong)_timer_rsc_phase2.milliseconds()); 332 } 333 } 334 335 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) { 336 // classes for primitives cannot be redefined 337 if (java_lang_Class::is_primitive(klass_mirror)) { 338 return false; 339 } 340 Klass* k = java_lang_Class::as_Klass(klass_mirror); 341 // classes for arrays cannot be redefined 342 if (k == nullptr || !k->is_instance_klass()) { 343 return false; 344 } 345 346 // Cannot redefine or retransform a hidden class. 347 if (InstanceKlass::cast(k)->is_hidden()) { 348 return false; 349 } 350 if (InstanceKlass::cast(k) == vmClasses::Continuation_klass()) { 351 // Don't redefine Continuation class. See 8302779. 352 return false; 353 } 354 return true; 355 } 356 357 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p 358 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For 359 // direct CP entries, there is just the current entry to append. For 360 // indirect and double-indirect CP entries, there are zero or more 361 // referenced CP entries along with the current entry to append. 362 // Indirect and double-indirect CP entries are handled by recursive 363 // calls to append_entry() as needed. The referenced CP entries are 364 // always appended to *merge_cp_p before the referee CP entry. These 365 // referenced CP entries may already exist in *merge_cp_p in which case 366 // there is nothing extra to append and only the current entry is 367 // appended. 368 void VM_RedefineClasses::append_entry(const constantPoolHandle& scratch_cp, 369 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) { 370 371 // append is different depending on entry tag type 372 switch (scratch_cp->tag_at(scratch_i).value()) { 373 374 // The old verifier is implemented outside the VM. It loads classes, 375 // but does not resolve constant pool entries directly so we never 376 // see Class entries here with the old verifier. Similarly the old 377 // verifier does not like Class entries in the input constant pool. 378 // The split-verifier is implemented in the VM so it can optionally 379 // and directly resolve constant pool entries to load classes. The 380 // split-verifier can accept either Class entries or UnresolvedClass 381 // entries in the input constant pool. We revert the appended copy 382 // back to UnresolvedClass so that either verifier will be happy 383 // with the constant pool entry. 384 // 385 // this is an indirect CP entry so it needs special handling 386 case JVM_CONSTANT_Class: 387 case JVM_CONSTANT_UnresolvedClass: 388 { 389 int name_i = scratch_cp->klass_name_index_at(scratch_i); 390 int new_name_i = find_or_append_indirect_entry(scratch_cp, name_i, merge_cp_p, 391 merge_cp_length_p); 392 393 if (new_name_i != name_i) { 394 log_trace(redefine, class, constantpool) 395 ("Class entry@%d name_index change: %d to %d", 396 *merge_cp_length_p, name_i, new_name_i); 397 } 398 399 (*merge_cp_p)->temp_unresolved_klass_at_put(*merge_cp_length_p, new_name_i); 400 if (scratch_i != *merge_cp_length_p) { 401 // The new entry in *merge_cp_p is at a different index than 402 // the new entry in scratch_cp so we need to map the index values. 403 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 404 } 405 (*merge_cp_length_p)++; 406 } break; 407 408 // these are direct CP entries so they can be directly appended, 409 // but double and long take two constant pool entries 410 case JVM_CONSTANT_Double: // fall through 411 case JVM_CONSTANT_Long: 412 { 413 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p); 414 415 if (scratch_i != *merge_cp_length_p) { 416 // The new entry in *merge_cp_p is at a different index than 417 // the new entry in scratch_cp so we need to map the index values. 418 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 419 } 420 (*merge_cp_length_p) += 2; 421 } break; 422 423 // these are direct CP entries so they can be directly appended 424 case JVM_CONSTANT_Float: // fall through 425 case JVM_CONSTANT_Integer: // fall through 426 case JVM_CONSTANT_Utf8: // fall through 427 428 // This was an indirect CP entry, but it has been changed into 429 // Symbol*s so this entry can be directly appended. 430 case JVM_CONSTANT_String: // fall through 431 { 432 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p); 433 434 if (scratch_i != *merge_cp_length_p) { 435 // The new entry in *merge_cp_p is at a different index than 436 // the new entry in scratch_cp so we need to map the index values. 437 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 438 } 439 (*merge_cp_length_p)++; 440 } break; 441 442 // this is an indirect CP entry so it needs special handling 443 case JVM_CONSTANT_NameAndType: 444 { 445 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i); 446 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p, 447 merge_cp_length_p); 448 449 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i); 450 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i, 451 merge_cp_p, merge_cp_length_p); 452 453 // If the referenced entries already exist in *merge_cp_p, then 454 // both new_name_ref_i and new_signature_ref_i will both be 0. 455 // In that case, all we are appending is the current entry. 456 if (new_name_ref_i != name_ref_i) { 457 log_trace(redefine, class, constantpool) 458 ("NameAndType entry@%d name_ref_index change: %d to %d", 459 *merge_cp_length_p, name_ref_i, new_name_ref_i); 460 } 461 if (new_signature_ref_i != signature_ref_i) { 462 log_trace(redefine, class, constantpool) 463 ("NameAndType entry@%d signature_ref_index change: %d to %d", 464 *merge_cp_length_p, signature_ref_i, new_signature_ref_i); 465 } 466 467 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p, 468 new_name_ref_i, new_signature_ref_i); 469 if (scratch_i != *merge_cp_length_p) { 470 // The new entry in *merge_cp_p is at a different index than 471 // the new entry in scratch_cp so we need to map the index values. 472 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 473 } 474 (*merge_cp_length_p)++; 475 } break; 476 477 // this is a double-indirect CP entry so it needs special handling 478 case JVM_CONSTANT_Fieldref: // fall through 479 case JVM_CONSTANT_InterfaceMethodref: // fall through 480 case JVM_CONSTANT_Methodref: 481 { 482 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i); 483 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i, 484 merge_cp_p, merge_cp_length_p); 485 486 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i); 487 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i, 488 merge_cp_p, merge_cp_length_p); 489 490 const char *entry_name = nullptr; 491 switch (scratch_cp->tag_at(scratch_i).value()) { 492 case JVM_CONSTANT_Fieldref: 493 entry_name = "Fieldref"; 494 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i, 495 new_name_and_type_ref_i); 496 break; 497 case JVM_CONSTANT_InterfaceMethodref: 498 entry_name = "IFMethodref"; 499 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p, 500 new_klass_ref_i, new_name_and_type_ref_i); 501 break; 502 case JVM_CONSTANT_Methodref: 503 entry_name = "Methodref"; 504 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i, 505 new_name_and_type_ref_i); 506 break; 507 default: 508 guarantee(false, "bad switch"); 509 break; 510 } 511 512 if (klass_ref_i != new_klass_ref_i) { 513 log_trace(redefine, class, constantpool) 514 ("%s entry@%d class_index changed: %d to %d", entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i); 515 } 516 if (name_and_type_ref_i != new_name_and_type_ref_i) { 517 log_trace(redefine, class, constantpool) 518 ("%s entry@%d name_and_type_index changed: %d to %d", 519 entry_name, *merge_cp_length_p, name_and_type_ref_i, new_name_and_type_ref_i); 520 } 521 522 if (scratch_i != *merge_cp_length_p) { 523 // The new entry in *merge_cp_p is at a different index than 524 // the new entry in scratch_cp so we need to map the index values. 525 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 526 } 527 (*merge_cp_length_p)++; 528 } break; 529 530 // this is an indirect CP entry so it needs special handling 531 case JVM_CONSTANT_MethodType: 532 { 533 int ref_i = scratch_cp->method_type_index_at(scratch_i); 534 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p, 535 merge_cp_length_p); 536 if (new_ref_i != ref_i) { 537 log_trace(redefine, class, constantpool) 538 ("MethodType entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i); 539 } 540 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i); 541 if (scratch_i != *merge_cp_length_p) { 542 // The new entry in *merge_cp_p is at a different index than 543 // the new entry in scratch_cp so we need to map the index values. 544 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 545 } 546 (*merge_cp_length_p)++; 547 } break; 548 549 // this is an indirect CP entry so it needs special handling 550 case JVM_CONSTANT_MethodHandle: 551 { 552 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i); 553 int ref_i = scratch_cp->method_handle_index_at(scratch_i); 554 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p, 555 merge_cp_length_p); 556 if (new_ref_i != ref_i) { 557 log_trace(redefine, class, constantpool) 558 ("MethodHandle entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i); 559 } 560 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i); 561 if (scratch_i != *merge_cp_length_p) { 562 // The new entry in *merge_cp_p is at a different index than 563 // the new entry in scratch_cp so we need to map the index values. 564 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 565 } 566 (*merge_cp_length_p)++; 567 } break; 568 569 // this is an indirect CP entry so it needs special handling 570 case JVM_CONSTANT_Dynamic: // fall through 571 case JVM_CONSTANT_InvokeDynamic: 572 { 573 // Index of the bootstrap specifier in the operands array 574 int old_bs_i = scratch_cp->bootstrap_methods_attribute_index(scratch_i); 575 int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p, 576 merge_cp_length_p); 577 // The bootstrap method NameAndType_info index 578 int old_ref_i = scratch_cp->bootstrap_name_and_type_ref_index_at(scratch_i); 579 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p, 580 merge_cp_length_p); 581 if (new_bs_i != old_bs_i) { 582 log_trace(redefine, class, constantpool) 583 ("Dynamic entry@%d bootstrap_method_attr_index change: %d to %d", 584 *merge_cp_length_p, old_bs_i, new_bs_i); 585 } 586 if (new_ref_i != old_ref_i) { 587 log_trace(redefine, class, constantpool) 588 ("Dynamic entry@%d name_and_type_index change: %d to %d", *merge_cp_length_p, old_ref_i, new_ref_i); 589 } 590 591 if (scratch_cp->tag_at(scratch_i).is_dynamic_constant()) 592 (*merge_cp_p)->dynamic_constant_at_put(*merge_cp_length_p, new_bs_i, new_ref_i); 593 else 594 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i); 595 if (scratch_i != *merge_cp_length_p) { 596 // The new entry in *merge_cp_p is at a different index than 597 // the new entry in scratch_cp so we need to map the index values. 598 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 599 } 600 (*merge_cp_length_p)++; 601 } break; 602 603 // At this stage, Class or UnresolvedClass could be in scratch_cp, but not 604 // ClassIndex 605 case JVM_CONSTANT_ClassIndex: // fall through 606 607 // Invalid is used as the tag for the second constant pool entry 608 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should 609 // not be seen by itself. 610 case JVM_CONSTANT_Invalid: // fall through 611 612 // At this stage, String could be here, but not StringIndex 613 case JVM_CONSTANT_StringIndex: // fall through 614 615 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be here 616 case JVM_CONSTANT_UnresolvedClassInError: // fall through 617 618 default: 619 { 620 // leave a breadcrumb 621 jbyte bad_value = scratch_cp->tag_at(scratch_i).value(); 622 ShouldNotReachHere(); 623 } break; 624 } // end switch tag value 625 } // end append_entry() 626 627 628 u2 VM_RedefineClasses::find_or_append_indirect_entry(const constantPoolHandle& scratch_cp, 629 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) { 630 631 int new_ref_i = ref_i; 632 bool match = (ref_i < *merge_cp_length_p) && 633 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i); 634 635 if (!match) { 636 // forward reference in *merge_cp_p or not a direct match 637 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p); 638 if (found_i != 0) { 639 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree"); 640 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry. 641 new_ref_i = found_i; 642 map_index(scratch_cp, ref_i, found_i); 643 } else { 644 // no match found so we have to append this entry to *merge_cp_p 645 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p); 646 // The above call to append_entry() can only append one entry 647 // so the post call query of *merge_cp_length_p is only for 648 // the sake of consistency. 649 new_ref_i = *merge_cp_length_p - 1; 650 } 651 } 652 653 // constant pool indices are u2, unless the merged constant pool overflows which 654 // we don't check for. 655 return checked_cast<u2>(new_ref_i); 656 } // end find_or_append_indirect_entry() 657 658 659 // Append a bootstrap specifier into the merge_cp operands that is semantically equal 660 // to the scratch_cp operands bootstrap specifier passed by the old_bs_i index. 661 // Recursively append new merge_cp entries referenced by the new bootstrap specifier. 662 void VM_RedefineClasses::append_operand(const constantPoolHandle& scratch_cp, int old_bs_i, 663 constantPoolHandle *merge_cp_p, int *merge_cp_length_p) { 664 665 u2 old_ref_i = scratch_cp->operand_bootstrap_method_ref_index_at(old_bs_i); 666 u2 new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p, 667 merge_cp_length_p); 668 if (new_ref_i != old_ref_i) { 669 log_trace(redefine, class, constantpool) 670 ("operands entry@%d bootstrap method ref_index change: %d to %d", _operands_cur_length, old_ref_i, new_ref_i); 671 } 672 673 Array<u2>* merge_ops = (*merge_cp_p)->operands(); 674 int new_bs_i = _operands_cur_length; 675 // We have _operands_cur_length == 0 when the merge_cp operands is empty yet. 676 // However, the operand_offset_at(0) was set in the extend_operands() call. 677 int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0) 678 : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1); 679 u2 argc = scratch_cp->operand_argument_count_at(old_bs_i); 680 681 ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base); 682 merge_ops->at_put(new_base++, new_ref_i); 683 merge_ops->at_put(new_base++, argc); 684 685 for (int i = 0; i < argc; i++) { 686 u2 old_arg_ref_i = scratch_cp->operand_argument_index_at(old_bs_i, i); 687 u2 new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p, 688 merge_cp_length_p); 689 merge_ops->at_put(new_base++, new_arg_ref_i); 690 if (new_arg_ref_i != old_arg_ref_i) { 691 log_trace(redefine, class, constantpool) 692 ("operands entry@%d bootstrap method argument ref_index change: %d to %d", 693 _operands_cur_length, old_arg_ref_i, new_arg_ref_i); 694 } 695 } 696 if (old_bs_i != _operands_cur_length) { 697 // The bootstrap specifier in *merge_cp_p is at a different index than 698 // that in scratch_cp so we need to map the index values. 699 map_operand_index(old_bs_i, new_bs_i); 700 } 701 _operands_cur_length++; 702 } // end append_operand() 703 704 705 int VM_RedefineClasses::find_or_append_operand(const constantPoolHandle& scratch_cp, 706 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) { 707 708 int new_bs_i = old_bs_i; // bootstrap specifier index 709 bool match = (old_bs_i < _operands_cur_length) && 710 scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i); 711 712 if (!match) { 713 // forward reference in *merge_cp_p or not a direct match 714 int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p, 715 _operands_cur_length); 716 if (found_i != -1) { 717 guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree"); 718 // found a matching operand somewhere else in *merge_cp_p so just need a mapping 719 new_bs_i = found_i; 720 map_operand_index(old_bs_i, found_i); 721 } else { 722 // no match found so we have to append this bootstrap specifier to *merge_cp_p 723 append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p); 724 new_bs_i = _operands_cur_length - 1; 725 } 726 } 727 return new_bs_i; 728 } // end find_or_append_operand() 729 730 731 void VM_RedefineClasses::finalize_operands_merge(const constantPoolHandle& merge_cp, TRAPS) { 732 if (merge_cp->operands() == nullptr) { 733 return; 734 } 735 // Shrink the merge_cp operands 736 merge_cp->shrink_operands(_operands_cur_length, CHECK); 737 738 if (log_is_enabled(Trace, redefine, class, constantpool)) { 739 // don't want to loop unless we are tracing 740 int count = 0; 741 for (int i = 1; i < _operands_index_map_p->length(); i++) { 742 int value = _operands_index_map_p->at(i); 743 if (value != -1) { 744 log_trace(redefine, class, constantpool)("operands_index_map[%d]: old=%d new=%d", count, i, value); 745 count++; 746 } 747 } 748 } 749 // Clean-up 750 _operands_index_map_p = nullptr; 751 _operands_cur_length = 0; 752 _operands_index_map_count = 0; 753 } // end finalize_operands_merge() 754 755 // Symbol* comparator for qsort 756 // The caller must have an active ResourceMark. 757 static int symcmp(const void* a, const void* b) { 758 char* astr = (*(Symbol**)a)->as_C_string(); 759 char* bstr = (*(Symbol**)b)->as_C_string(); 760 return strcmp(astr, bstr); 761 } 762 763 // The caller must have an active ResourceMark. 764 static jvmtiError check_attribute_arrays(const char* attr_name, 765 InstanceKlass* the_class, InstanceKlass* scratch_class, 766 Array<u2>* the_array, Array<u2>* scr_array) { 767 bool the_array_exists = the_array != Universe::the_empty_short_array(); 768 bool scr_array_exists = scr_array != Universe::the_empty_short_array(); 769 770 int array_len = the_array->length(); 771 if (the_array_exists && scr_array_exists) { 772 if (array_len != scr_array->length()) { 773 log_trace(redefine, class) 774 ("redefined class %s attribute change error: %s len=%d changed to len=%d", 775 the_class->external_name(), attr_name, array_len, scr_array->length()); 776 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 777 } 778 779 // The order of entries in the attribute array is not specified so we 780 // have to explicitly check for the same contents. We do this by copying 781 // the referenced symbols into their own arrays, sorting them and then 782 // comparing each element pair. 783 784 Symbol** the_syms = NEW_RESOURCE_ARRAY_RETURN_NULL(Symbol*, array_len); 785 Symbol** scr_syms = NEW_RESOURCE_ARRAY_RETURN_NULL(Symbol*, array_len); 786 787 if (the_syms == nullptr || scr_syms == nullptr) { 788 return JVMTI_ERROR_OUT_OF_MEMORY; 789 } 790 791 for (int i = 0; i < array_len; i++) { 792 int the_cp_index = the_array->at(i); 793 int scr_cp_index = scr_array->at(i); 794 the_syms[i] = the_class->constants()->klass_name_at(the_cp_index); 795 scr_syms[i] = scratch_class->constants()->klass_name_at(scr_cp_index); 796 } 797 798 qsort(the_syms, array_len, sizeof(Symbol*), symcmp); 799 qsort(scr_syms, array_len, sizeof(Symbol*), symcmp); 800 801 for (int i = 0; i < array_len; i++) { 802 if (the_syms[i] != scr_syms[i]) { 803 log_info(redefine, class) 804 ("redefined class %s attribute change error: %s[%d]: %s changed to %s", 805 the_class->external_name(), attr_name, i, 806 the_syms[i]->as_C_string(), scr_syms[i]->as_C_string()); 807 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 808 } 809 } 810 } else if (the_array_exists ^ scr_array_exists) { 811 const char* action_str = (the_array_exists) ? "removed" : "added"; 812 log_info(redefine, class) 813 ("redefined class %s attribute change error: %s attribute %s", 814 the_class->external_name(), attr_name, action_str); 815 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 816 } 817 return JVMTI_ERROR_NONE; 818 } 819 820 static jvmtiError check_nest_attributes(InstanceKlass* the_class, 821 InstanceKlass* scratch_class) { 822 // Check whether the class NestHost attribute has been changed. 823 Thread* thread = Thread::current(); 824 ResourceMark rm(thread); 825 u2 the_nest_host_idx = the_class->nest_host_index(); 826 u2 scr_nest_host_idx = scratch_class->nest_host_index(); 827 828 if (the_nest_host_idx != 0 && scr_nest_host_idx != 0) { 829 Symbol* the_sym = the_class->constants()->klass_name_at(the_nest_host_idx); 830 Symbol* scr_sym = scratch_class->constants()->klass_name_at(scr_nest_host_idx); 831 if (the_sym != scr_sym) { 832 log_info(redefine, class, nestmates) 833 ("redefined class %s attribute change error: NestHost class: %s replaced with: %s", 834 the_class->external_name(), the_sym->as_C_string(), scr_sym->as_C_string()); 835 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 836 } 837 } else if ((the_nest_host_idx == 0) ^ (scr_nest_host_idx == 0)) { 838 const char* action_str = (the_nest_host_idx != 0) ? "removed" : "added"; 839 log_info(redefine, class, nestmates) 840 ("redefined class %s attribute change error: NestHost attribute %s", 841 the_class->external_name(), action_str); 842 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 843 } 844 845 // Check whether the class NestMembers attribute has been changed. 846 return check_attribute_arrays("NestMembers", 847 the_class, scratch_class, 848 the_class->nest_members(), 849 scratch_class->nest_members()); 850 } 851 852 // Return an error status if the class Record attribute was changed. 853 static jvmtiError check_record_attribute(InstanceKlass* the_class, InstanceKlass* scratch_class) { 854 // Get lists of record components. 855 Array<RecordComponent*>* the_record = the_class->record_components(); 856 Array<RecordComponent*>* scr_record = scratch_class->record_components(); 857 bool the_record_exists = the_record != nullptr; 858 bool scr_record_exists = scr_record != nullptr; 859 860 if (the_record_exists && scr_record_exists) { 861 int the_num_components = the_record->length(); 862 int scr_num_components = scr_record->length(); 863 if (the_num_components != scr_num_components) { 864 log_info(redefine, class, record) 865 ("redefined class %s attribute change error: Record num_components=%d changed to num_components=%d", 866 the_class->external_name(), the_num_components, scr_num_components); 867 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 868 } 869 870 // Compare each field in each record component. 871 ConstantPool* the_cp = the_class->constants(); 872 ConstantPool* scr_cp = scratch_class->constants(); 873 for (int x = 0; x < the_num_components; x++) { 874 RecordComponent* the_component = the_record->at(x); 875 RecordComponent* scr_component = scr_record->at(x); 876 const Symbol* const the_name = the_cp->symbol_at(the_component->name_index()); 877 const Symbol* const scr_name = scr_cp->symbol_at(scr_component->name_index()); 878 const Symbol* const the_descr = the_cp->symbol_at(the_component->descriptor_index()); 879 const Symbol* const scr_descr = scr_cp->symbol_at(scr_component->descriptor_index()); 880 if (the_name != scr_name || the_descr != scr_descr) { 881 log_info(redefine, class, record) 882 ("redefined class %s attribute change error: Record name_index, descriptor_index, and/or attributes_count changed", 883 the_class->external_name()); 884 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 885 } 886 887 int the_gen_sig = the_component->generic_signature_index(); 888 int scr_gen_sig = scr_component->generic_signature_index(); 889 const Symbol* const the_gen_sig_sym = (the_gen_sig == 0 ? nullptr : 890 the_cp->symbol_at(the_component->generic_signature_index())); 891 const Symbol* const scr_gen_sig_sym = (scr_gen_sig == 0 ? nullptr : 892 scr_cp->symbol_at(scr_component->generic_signature_index())); 893 if (the_gen_sig_sym != scr_gen_sig_sym) { 894 log_info(redefine, class, record) 895 ("redefined class %s attribute change error: Record generic_signature attribute changed", 896 the_class->external_name()); 897 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 898 } 899 900 // It's okay if a record component's annotations were changed. 901 } 902 903 } else if (the_record_exists ^ scr_record_exists) { 904 const char* action_str = (the_record_exists) ? "removed" : "added"; 905 log_info(redefine, class, record) 906 ("redefined class %s attribute change error: Record attribute %s", 907 the_class->external_name(), action_str); 908 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 909 } 910 911 return JVMTI_ERROR_NONE; 912 } 913 914 915 static jvmtiError check_permitted_subclasses_attribute(InstanceKlass* the_class, 916 InstanceKlass* scratch_class) { 917 Thread* thread = Thread::current(); 918 ResourceMark rm(thread); 919 920 // Check whether the class PermittedSubclasses attribute has been changed. 921 return check_attribute_arrays("PermittedSubclasses", 922 the_class, scratch_class, 923 the_class->permitted_subclasses(), 924 scratch_class->permitted_subclasses()); 925 } 926 927 static bool can_add_or_delete(Method* m) { 928 // Compatibility mode 929 return (AllowRedefinitionToAddDeleteMethods && 930 (m->is_private() && (m->is_static() || m->is_final()))); 931 } 932 933 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions( 934 InstanceKlass* the_class, 935 InstanceKlass* scratch_class) { 936 int i; 937 938 // Check superclasses, or rather their names, since superclasses themselves can be 939 // requested to replace. 940 // Check for null superclass first since this might be java.lang.Object 941 if (the_class->super() != scratch_class->super() && 942 (the_class->super() == nullptr || scratch_class->super() == nullptr || 943 the_class->super()->name() != 944 scratch_class->super()->name())) { 945 log_info(redefine, class, normalize) 946 ("redefined class %s superclass change error: superclass changed from %s to %s.", 947 the_class->external_name(), 948 the_class->super() == nullptr ? "null" : the_class->super()->external_name(), 949 scratch_class->super() == nullptr ? "null" : scratch_class->super()->external_name()); 950 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 951 } 952 953 // Check if the number, names and order of directly implemented interfaces are the same. 954 // I think in principle we should just check if the sets of names of directly implemented 955 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the 956 // .java file, also changes in .class file) should not matter. However, comparing sets is 957 // technically a bit more difficult, and, more importantly, I am not sure at present that the 958 // order of interfaces does not matter on the implementation level, i.e. that the VM does not 959 // rely on it somewhere. 960 Array<InstanceKlass*>* k_interfaces = the_class->local_interfaces(); 961 Array<InstanceKlass*>* k_new_interfaces = scratch_class->local_interfaces(); 962 int n_intfs = k_interfaces->length(); 963 if (n_intfs != k_new_interfaces->length()) { 964 log_info(redefine, class, normalize) 965 ("redefined class %s interfaces change error: number of implemented interfaces changed from %d to %d.", 966 the_class->external_name(), n_intfs, k_new_interfaces->length()); 967 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 968 } 969 for (i = 0; i < n_intfs; i++) { 970 if (k_interfaces->at(i)->name() != 971 k_new_interfaces->at(i)->name()) { 972 log_info(redefine, class, normalize) 973 ("redefined class %s interfaces change error: interface changed from %s to %s.", 974 the_class->external_name(), 975 k_interfaces->at(i)->external_name(), k_new_interfaces->at(i)->external_name()); 976 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 977 } 978 } 979 980 // Check whether class is in the error init state. 981 if (the_class->is_in_error_state()) { 982 log_info(redefine, class, normalize) 983 ("redefined class %s is in error init state.", the_class->external_name()); 984 // TBD #5057930: special error code is needed in 1.6 985 return JVMTI_ERROR_INVALID_CLASS; 986 } 987 988 // Check whether the nest-related attributes have been changed. 989 jvmtiError err = check_nest_attributes(the_class, scratch_class); 990 if (err != JVMTI_ERROR_NONE) { 991 return err; 992 } 993 994 // Check whether the Record attribute has been changed. 995 err = check_record_attribute(the_class, scratch_class); 996 if (err != JVMTI_ERROR_NONE) { 997 return err; 998 } 999 1000 // Check whether the PermittedSubclasses attribute has been changed. 1001 err = check_permitted_subclasses_attribute(the_class, scratch_class); 1002 if (err != JVMTI_ERROR_NONE) { 1003 return err; 1004 } 1005 1006 // Check whether class modifiers are the same. 1007 u2 old_flags = the_class->access_flags().as_class_flags(); 1008 u2 new_flags = scratch_class->access_flags().as_class_flags(); 1009 if (old_flags != new_flags) { 1010 log_info(redefine, class, normalize) 1011 ("redefined class %s modifiers change error: modifiers changed from %d to %d.", 1012 the_class->external_name(), old_flags, new_flags); 1013 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED; 1014 } 1015 1016 // Check if the number, names, types and order of fields declared in these classes 1017 // are the same. 1018 JavaFieldStream old_fs(the_class); 1019 JavaFieldStream new_fs(scratch_class); 1020 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) { 1021 // name and signature 1022 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index()); 1023 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index()); 1024 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index()); 1025 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index()); 1026 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) { 1027 log_info(redefine, class, normalize) 1028 ("redefined class %s fields change error: field %s %s changed to %s %s.", 1029 the_class->external_name(), 1030 sig_sym1->as_C_string(), name_sym1->as_C_string(), 1031 sig_sym2->as_C_string(), name_sym2->as_C_string()); 1032 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 1033 } 1034 // offset 1035 if (old_fs.offset() != new_fs.offset()) { 1036 log_info(redefine, class, normalize) 1037 ("redefined class %s field %s change error: offset changed from %d to %d.", 1038 the_class->external_name(), name_sym2->as_C_string(), old_fs.offset(), new_fs.offset()); 1039 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 1040 } 1041 // access 1042 old_flags = old_fs.access_flags().as_field_flags(); 1043 new_flags = new_fs.access_flags().as_field_flags(); 1044 if (old_flags != new_flags) { 1045 log_info(redefine, class, normalize) 1046 ("redefined class %s field %s change error: modifiers changed from %d to %d.", 1047 the_class->external_name(), name_sym2->as_C_string(), old_flags, new_flags); 1048 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 1049 } 1050 } 1051 1052 // If both streams aren't done then we have a differing number of 1053 // fields. 1054 if (!old_fs.done() || !new_fs.done()) { 1055 const char* action = old_fs.done() ? "added" : "deleted"; 1056 log_info(redefine, class, normalize) 1057 ("redefined class %s fields change error: some fields were %s.", 1058 the_class->external_name(), action); 1059 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 1060 } 1061 1062 // Do a parallel walk through the old and new methods. Detect 1063 // cases where they match (exist in both), have been added in 1064 // the new methods, or have been deleted (exist only in the 1065 // old methods). The class file parser places methods in order 1066 // by method name, but does not order overloaded methods by 1067 // signature. In order to determine what fate befell the methods, 1068 // this code places the overloaded new methods that have matching 1069 // old methods in the same order as the old methods and places 1070 // new overloaded methods at the end of overloaded methods of 1071 // that name. The code for this order normalization is adapted 1072 // from the algorithm used in InstanceKlass::find_method(). 1073 // Since we are swapping out of order entries as we find them, 1074 // we only have to search forward through the overloaded methods. 1075 // Methods which are added and have the same name as an existing 1076 // method (but different signature) will be put at the end of 1077 // the methods with that name, and the name mismatch code will 1078 // handle them. 1079 Array<Method*>* k_old_methods(the_class->methods()); 1080 Array<Method*>* k_new_methods(scratch_class->methods()); 1081 int n_old_methods = k_old_methods->length(); 1082 int n_new_methods = k_new_methods->length(); 1083 Thread* thread = Thread::current(); 1084 1085 int ni = 0; 1086 int oi = 0; 1087 while (true) { 1088 Method* k_old_method; 1089 Method* k_new_method; 1090 enum { matched, added, deleted, undetermined } method_was = undetermined; 1091 1092 if (oi >= n_old_methods) { 1093 if (ni >= n_new_methods) { 1094 break; // we've looked at everything, done 1095 } 1096 // New method at the end 1097 k_new_method = k_new_methods->at(ni); 1098 method_was = added; 1099 } else if (ni >= n_new_methods) { 1100 // Old method, at the end, is deleted 1101 k_old_method = k_old_methods->at(oi); 1102 method_was = deleted; 1103 } else { 1104 // There are more methods in both the old and new lists 1105 k_old_method = k_old_methods->at(oi); 1106 k_new_method = k_new_methods->at(ni); 1107 if (k_old_method->name() != k_new_method->name()) { 1108 // Methods are sorted by method name, so a mismatch means added 1109 // or deleted 1110 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) { 1111 method_was = added; 1112 } else { 1113 method_was = deleted; 1114 } 1115 } else if (k_old_method->signature() == k_new_method->signature()) { 1116 // Both the name and signature match 1117 method_was = matched; 1118 } else { 1119 // The name matches, but the signature doesn't, which means we have to 1120 // search forward through the new overloaded methods. 1121 int nj; // outside the loop for post-loop check 1122 for (nj = ni + 1; nj < n_new_methods; nj++) { 1123 Method* m = k_new_methods->at(nj); 1124 if (k_old_method->name() != m->name()) { 1125 // reached another method name so no more overloaded methods 1126 method_was = deleted; 1127 break; 1128 } 1129 if (k_old_method->signature() == m->signature()) { 1130 // found a match so swap the methods 1131 k_new_methods->at_put(ni, m); 1132 k_new_methods->at_put(nj, k_new_method); 1133 k_new_method = m; 1134 method_was = matched; 1135 break; 1136 } 1137 } 1138 1139 if (nj >= n_new_methods) { 1140 // reached the end without a match; so method was deleted 1141 method_was = deleted; 1142 } 1143 } 1144 } 1145 1146 switch (method_was) { 1147 case matched: 1148 // methods match, be sure modifiers do too 1149 old_flags = k_old_method->access_flags().as_method_flags(); 1150 new_flags = k_new_method->access_flags().as_method_flags(); 1151 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) { 1152 log_info(redefine, class, normalize) 1153 ("redefined class %s method %s modifiers error: modifiers changed from %d to %d", 1154 the_class->external_name(), k_old_method->name_and_sig_as_C_string(), old_flags, new_flags); 1155 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED; 1156 } 1157 { 1158 u2 new_num = k_new_method->method_idnum(); 1159 u2 old_num = k_old_method->method_idnum(); 1160 if (new_num != old_num) { 1161 Method* idnum_owner = scratch_class->method_with_idnum(old_num); 1162 if (idnum_owner != nullptr) { 1163 // There is already a method assigned this idnum -- switch them 1164 // Take current and original idnum from the new_method 1165 idnum_owner->set_method_idnum(new_num); 1166 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum()); 1167 } 1168 // Take current and original idnum from the old_method 1169 k_new_method->set_method_idnum(old_num); 1170 k_new_method->set_orig_method_idnum(k_old_method->orig_method_idnum()); 1171 if (thread->has_pending_exception()) { 1172 return JVMTI_ERROR_OUT_OF_MEMORY; 1173 } 1174 } 1175 } 1176 JFR_ONLY(k_new_method->copy_trace_flags(k_old_method->trace_flags());) 1177 log_trace(redefine, class, normalize) 1178 ("Method matched: new: %s [%d] == old: %s [%d]", 1179 k_new_method->name_and_sig_as_C_string(), ni, k_old_method->name_and_sig_as_C_string(), oi); 1180 // advance to next pair of methods 1181 ++oi; 1182 ++ni; 1183 break; 1184 case added: 1185 // method added, see if it is OK 1186 if (!can_add_or_delete(k_new_method)) { 1187 log_info(redefine, class, normalize) 1188 ("redefined class %s methods error: added method: %s [%d]", 1189 the_class->external_name(), k_new_method->name_and_sig_as_C_string(), ni); 1190 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED; 1191 } 1192 { 1193 u2 num = the_class->next_method_idnum(); 1194 if (num == ConstMethod::UNSET_IDNUM) { 1195 // cannot add any more methods 1196 log_info(redefine, class, normalize) 1197 ("redefined class %s methods error: can't create ID for new method %s [%d]", 1198 the_class->external_name(), k_new_method->name_and_sig_as_C_string(), ni); 1199 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED; 1200 } 1201 u2 new_num = k_new_method->method_idnum(); 1202 Method* idnum_owner = scratch_class->method_with_idnum(num); 1203 if (idnum_owner != nullptr) { 1204 // There is already a method assigned this idnum -- switch them 1205 // Take current and original idnum from the new_method 1206 idnum_owner->set_method_idnum(new_num); 1207 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum()); 1208 } 1209 k_new_method->set_method_idnum(num); 1210 k_new_method->set_orig_method_idnum(num); 1211 if (thread->has_pending_exception()) { 1212 return JVMTI_ERROR_OUT_OF_MEMORY; 1213 } 1214 } 1215 log_trace(redefine, class, normalize) 1216 ("Method added: new: %s [%d]", k_new_method->name_and_sig_as_C_string(), ni); 1217 ++ni; // advance to next new method 1218 break; 1219 case deleted: 1220 // method deleted, see if it is OK 1221 if (!can_add_or_delete(k_old_method)) { 1222 log_info(redefine, class, normalize) 1223 ("redefined class %s methods error: deleted method %s [%d]", 1224 the_class->external_name(), k_old_method->name_and_sig_as_C_string(), oi); 1225 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED; 1226 } 1227 log_trace(redefine, class, normalize) 1228 ("Method deleted: old: %s [%d]", k_old_method->name_and_sig_as_C_string(), oi); 1229 ++oi; // advance to next old method 1230 break; 1231 default: 1232 ShouldNotReachHere(); 1233 } 1234 } 1235 1236 return JVMTI_ERROR_NONE; 1237 } 1238 1239 1240 // Find new constant pool index value for old constant pool index value 1241 // by searching the index map. Returns zero (0) if there is no mapped 1242 // value for the old constant pool index. 1243 u2 VM_RedefineClasses::find_new_index(int old_index) { 1244 if (_index_map_count == 0) { 1245 // map is empty so nothing can be found 1246 return 0; 1247 } 1248 1249 if (old_index < 1 || old_index >= _index_map_p->length()) { 1250 // The old_index is out of range so it is not mapped. This should 1251 // not happen in regular constant pool merging use, but it can 1252 // happen if a corrupt annotation is processed. 1253 return 0; 1254 } 1255 1256 int value = _index_map_p->at(old_index); 1257 if (value == -1) { 1258 // the old_index is not mapped 1259 return 0; 1260 } 1261 1262 // constant pool indices are u2, unless the merged constant pool overflows which 1263 // we don't check for. 1264 return checked_cast<u2>(value); 1265 } // end find_new_index() 1266 1267 1268 // Find new bootstrap specifier index value for old bootstrap specifier index 1269 // value by searching the index map. Returns unused index (-1) if there is 1270 // no mapped value for the old bootstrap specifier index. 1271 int VM_RedefineClasses::find_new_operand_index(int old_index) { 1272 if (_operands_index_map_count == 0) { 1273 // map is empty so nothing can be found 1274 return -1; 1275 } 1276 1277 if (old_index == -1 || old_index >= _operands_index_map_p->length()) { 1278 // The old_index is out of range so it is not mapped. 1279 // This should not happen in regular constant pool merging use. 1280 return -1; 1281 } 1282 1283 int value = _operands_index_map_p->at(old_index); 1284 if (value == -1) { 1285 // the old_index is not mapped 1286 return -1; 1287 } 1288 1289 return value; 1290 } // end find_new_operand_index() 1291 1292 1293 // The bug 6214132 caused the verification to fail. 1294 // 1. What's done in RedefineClasses() before verification: 1295 // a) A reference to the class being redefined (_the_class) and a 1296 // reference to new version of the class (_scratch_class) are 1297 // saved here for use during the bytecode verification phase of 1298 // RedefineClasses. 1299 // b) The _java_mirror field from _the_class is copied to the 1300 // _java_mirror field in _scratch_class. This means that a jclass 1301 // returned for _the_class or _scratch_class will refer to the 1302 // same Java mirror. The verifier will see the "one true mirror" 1303 // for the class being verified. 1304 // 2. See comments in JvmtiThreadState for what is done during verification. 1305 1306 class RedefineVerifyMark : public StackObj { 1307 private: 1308 JvmtiThreadState* _state; 1309 Klass* _scratch_class; 1310 OopHandle _scratch_mirror; 1311 1312 public: 1313 1314 RedefineVerifyMark(Klass* the_class, Klass* scratch_class, 1315 JvmtiThreadState* state) : _state(state), _scratch_class(scratch_class) 1316 { 1317 _state->set_class_versions_map(the_class, scratch_class); 1318 _scratch_mirror = the_class->java_mirror_handle(); // this is a copy that is swapped 1319 _scratch_class->swap_java_mirror_handle(_scratch_mirror); 1320 } 1321 1322 ~RedefineVerifyMark() { 1323 // Restore the scratch class's mirror, so when scratch_class is removed 1324 // the correct mirror pointing to it can be cleared. 1325 _scratch_class->swap_java_mirror_handle(_scratch_mirror); 1326 _state->clear_class_versions_map(); 1327 } 1328 }; 1329 1330 1331 jvmtiError VM_RedefineClasses::load_new_class_versions() { 1332 1333 // For consistency allocate memory using os::malloc wrapper. 1334 _scratch_classes = (InstanceKlass**) 1335 os::malloc(sizeof(InstanceKlass*) * _class_count, mtClass); 1336 if (_scratch_classes == nullptr) { 1337 return JVMTI_ERROR_OUT_OF_MEMORY; 1338 } 1339 // Zero initialize the _scratch_classes array. 1340 for (int i = 0; i < _class_count; i++) { 1341 _scratch_classes[i] = nullptr; 1342 } 1343 1344 JavaThread* current = JavaThread::current(); 1345 ResourceMark rm(current); 1346 1347 JvmtiThreadState *state = JvmtiThreadState::state_for(current); 1348 // state can only be null if the current thread is exiting which 1349 // should not happen since we're trying to do a RedefineClasses 1350 guarantee(state != nullptr, "exiting thread calling load_new_class_versions"); 1351 for (int i = 0; i < _class_count; i++) { 1352 // Create HandleMark so that any handles created while loading new class 1353 // versions are deleted. Constant pools are deallocated while merging 1354 // constant pools 1355 HandleMark hm(current); 1356 InstanceKlass* the_class = get_ik(_class_defs[i].klass); 1357 1358 log_debug(redefine, class, load) 1359 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)", 1360 the_class->external_name(), _class_load_kind, os::available_memory() >> 10); 1361 1362 ClassFileStream st((u1*)_class_defs[i].class_bytes, 1363 _class_defs[i].class_byte_count, 1364 "__VM_RedefineClasses__"); 1365 1366 // Set redefined class handle in JvmtiThreadState class. 1367 // This redefined class is sent to agent event handler for class file 1368 // load hook event. 1369 state->set_class_being_redefined(the_class, _class_load_kind); 1370 1371 JavaThread* THREAD = current; // For exception macros. 1372 ExceptionMark em(THREAD); 1373 Handle protection_domain(THREAD, the_class->protection_domain()); 1374 ClassLoadInfo cl_info(protection_domain); 1375 // Parse and create a class from the bytes, but this class isn't added 1376 // to the dictionary, so do not call resolve_from_stream. 1377 InstanceKlass* scratch_class = KlassFactory::create_from_stream(&st, 1378 the_class->name(), 1379 the_class->class_loader_data(), 1380 cl_info, 1381 THREAD); 1382 1383 // Clear class_being_redefined just to be sure. 1384 state->clear_class_being_redefined(); 1385 1386 // TODO: if this is retransform, and nothing changed we can skip it 1387 1388 // Need to clean up allocated InstanceKlass if there's an error so assign 1389 // the result here. Caller deallocates all the scratch classes in case of 1390 // an error. 1391 _scratch_classes[i] = scratch_class; 1392 1393 if (HAS_PENDING_EXCEPTION) { 1394 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1395 log_info(redefine, class, load, exceptions)("create_from_stream exception: '%s'", ex_name->as_C_string()); 1396 CLEAR_PENDING_EXCEPTION; 1397 1398 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) { 1399 return JVMTI_ERROR_UNSUPPORTED_VERSION; 1400 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) { 1401 return JVMTI_ERROR_INVALID_CLASS_FORMAT; 1402 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) { 1403 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION; 1404 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) { 1405 // The message will be "XXX (wrong name: YYY)" 1406 return JVMTI_ERROR_NAMES_DONT_MATCH; 1407 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1408 return JVMTI_ERROR_OUT_OF_MEMORY; 1409 } else { // Just in case more exceptions can be thrown.. 1410 return JVMTI_ERROR_FAILS_VERIFICATION; 1411 } 1412 } 1413 1414 // Ensure class is linked before redefine 1415 if (!the_class->is_linked()) { 1416 the_class->link_class(THREAD); 1417 if (HAS_PENDING_EXCEPTION) { 1418 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1419 oop message = java_lang_Throwable::message(PENDING_EXCEPTION); 1420 if (message != nullptr) { 1421 char* ex_msg = java_lang_String::as_utf8_string(message); 1422 log_info(redefine, class, load, exceptions)("link_class exception: '%s %s'", 1423 ex_name->as_C_string(), ex_msg); 1424 } else { 1425 log_info(redefine, class, load, exceptions)("link_class exception: '%s'", 1426 ex_name->as_C_string()); 1427 } 1428 CLEAR_PENDING_EXCEPTION; 1429 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1430 return JVMTI_ERROR_OUT_OF_MEMORY; 1431 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) { 1432 return JVMTI_ERROR_INVALID_CLASS; 1433 } else { 1434 return JVMTI_ERROR_INTERNAL; 1435 } 1436 } 1437 } 1438 1439 // Do the validity checks in compare_and_normalize_class_versions() 1440 // before verifying the byte codes. By doing these checks first, we 1441 // limit the number of functions that require redirection from 1442 // the_class to scratch_class. In particular, we don't have to 1443 // modify JNI GetSuperclass() and thus won't change its performance. 1444 jvmtiError res = compare_and_normalize_class_versions(the_class, 1445 scratch_class); 1446 if (res != JVMTI_ERROR_NONE) { 1447 return res; 1448 } 1449 1450 // verify what the caller passed us 1451 { 1452 // The bug 6214132 caused the verification to fail. 1453 // Information about the_class and scratch_class is temporarily 1454 // recorded into jvmtiThreadState. This data is used to redirect 1455 // the_class to scratch_class in the JVM_* functions called by the 1456 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed 1457 // description. 1458 RedefineVerifyMark rvm(the_class, scratch_class, state); 1459 Verifier::verify(scratch_class, true, THREAD); 1460 } 1461 1462 if (HAS_PENDING_EXCEPTION) { 1463 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1464 log_info(redefine, class, load, exceptions)("verify_byte_codes exception: '%s'", ex_name->as_C_string()); 1465 CLEAR_PENDING_EXCEPTION; 1466 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1467 return JVMTI_ERROR_OUT_OF_MEMORY; 1468 } else { 1469 // tell the caller the bytecodes are bad 1470 return JVMTI_ERROR_FAILS_VERIFICATION; 1471 } 1472 } 1473 1474 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD); 1475 if (HAS_PENDING_EXCEPTION) { 1476 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1477 log_info(redefine, class, load, exceptions)("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string()); 1478 CLEAR_PENDING_EXCEPTION; 1479 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1480 return JVMTI_ERROR_OUT_OF_MEMORY; 1481 } else { 1482 return JVMTI_ERROR_INTERNAL; 1483 } 1484 } 1485 1486 #ifdef ASSERT 1487 { 1488 // verify what we have done during constant pool merging 1489 { 1490 RedefineVerifyMark rvm(the_class, scratch_class, state); 1491 Verifier::verify(scratch_class, true, THREAD); 1492 } 1493 1494 if (HAS_PENDING_EXCEPTION) { 1495 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1496 log_info(redefine, class, load, exceptions) 1497 ("verify_byte_codes post merge-CP exception: '%s'", ex_name->as_C_string()); 1498 CLEAR_PENDING_EXCEPTION; 1499 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1500 return JVMTI_ERROR_OUT_OF_MEMORY; 1501 } else { 1502 // tell the caller that constant pool merging screwed up 1503 return JVMTI_ERROR_INTERNAL; 1504 } 1505 } 1506 } 1507 #endif // ASSERT 1508 1509 Rewriter::rewrite(scratch_class, THREAD); 1510 if (!HAS_PENDING_EXCEPTION) { 1511 scratch_class->link_methods(THREAD); 1512 } 1513 if (HAS_PENDING_EXCEPTION) { 1514 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1515 log_info(redefine, class, load, exceptions) 1516 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string()); 1517 CLEAR_PENDING_EXCEPTION; 1518 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1519 return JVMTI_ERROR_OUT_OF_MEMORY; 1520 } else { 1521 return JVMTI_ERROR_INTERNAL; 1522 } 1523 } 1524 1525 log_debug(redefine, class, load) 1526 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)", the_class->external_name(), os::available_memory() >> 10); 1527 } 1528 1529 return JVMTI_ERROR_NONE; 1530 } 1531 1532 1533 // Map old_index to new_index as needed. scratch_cp is only needed 1534 // for log calls. 1535 void VM_RedefineClasses::map_index(const constantPoolHandle& scratch_cp, 1536 int old_index, int new_index) { 1537 if (find_new_index(old_index) != 0) { 1538 // old_index is already mapped 1539 return; 1540 } 1541 1542 if (old_index == new_index) { 1543 // no mapping is needed 1544 return; 1545 } 1546 1547 _index_map_p->at_put(old_index, new_index); 1548 _index_map_count++; 1549 1550 log_trace(redefine, class, constantpool) 1551 ("mapped tag %d at index %d to %d", scratch_cp->tag_at(old_index).value(), old_index, new_index); 1552 } // end map_index() 1553 1554 1555 // Map old_index to new_index as needed. 1556 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) { 1557 if (find_new_operand_index(old_index) != -1) { 1558 // old_index is already mapped 1559 return; 1560 } 1561 1562 if (old_index == new_index) { 1563 // no mapping is needed 1564 return; 1565 } 1566 1567 _operands_index_map_p->at_put(old_index, new_index); 1568 _operands_index_map_count++; 1569 1570 log_trace(redefine, class, constantpool)("mapped bootstrap specifier at index %d to %d", old_index, new_index); 1571 } // end map_index() 1572 1573 1574 // Merge old_cp and scratch_cp and return the results of the merge via 1575 // merge_cp_p. The number of entries in *merge_cp_p is returned via 1576 // merge_cp_length_p. The entries in old_cp occupy the same locations 1577 // in *merge_cp_p. Also creates a map of indices from entries in 1578 // scratch_cp to the corresponding entry in *merge_cp_p. Index map 1579 // entries are only created for entries in scratch_cp that occupy a 1580 // different location in *merged_cp_p. 1581 bool VM_RedefineClasses::merge_constant_pools(const constantPoolHandle& old_cp, 1582 const constantPoolHandle& scratch_cp, constantPoolHandle *merge_cp_p, 1583 int *merge_cp_length_p, TRAPS) { 1584 1585 if (merge_cp_p == nullptr) { 1586 assert(false, "caller must provide scratch constantPool"); 1587 return false; // robustness 1588 } 1589 if (merge_cp_length_p == nullptr) { 1590 assert(false, "caller must provide scratch CP length"); 1591 return false; // robustness 1592 } 1593 // Worst case we need old_cp->length() + scratch_cp()->length(), 1594 // but the caller might be smart so make sure we have at least 1595 // the minimum. 1596 if ((*merge_cp_p)->length() < old_cp->length()) { 1597 assert(false, "merge area too small"); 1598 return false; // robustness 1599 } 1600 1601 log_info(redefine, class, constantpool)("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(), scratch_cp->length()); 1602 1603 { 1604 // Pass 0: 1605 // The old_cp is copied to *merge_cp_p; this means that any code 1606 // using old_cp does not have to change. This work looks like a 1607 // perfect fit for ConstantPool*::copy_cp_to(), but we need to 1608 // handle one special case: 1609 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass 1610 // This will make verification happy. 1611 1612 int old_i; // index into old_cp 1613 1614 // index zero (0) is not used in constantPools 1615 for (old_i = 1; old_i < old_cp->length(); old_i++) { 1616 // leave debugging crumb 1617 jbyte old_tag = old_cp->tag_at(old_i).value(); 1618 switch (old_tag) { 1619 case JVM_CONSTANT_Class: 1620 case JVM_CONSTANT_UnresolvedClass: 1621 // revert the copy to JVM_CONSTANT_UnresolvedClass 1622 // May be resolving while calling this so do the same for 1623 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition) 1624 (*merge_cp_p)->temp_unresolved_klass_at_put(old_i, 1625 old_cp->klass_name_index_at(old_i)); 1626 break; 1627 1628 case JVM_CONSTANT_Double: 1629 case JVM_CONSTANT_Long: 1630 // just copy the entry to *merge_cp_p, but double and long take 1631 // two constant pool entries 1632 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i); 1633 old_i++; 1634 break; 1635 1636 default: 1637 // just copy the entry to *merge_cp_p 1638 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i); 1639 break; 1640 } 1641 } // end for each old_cp entry 1642 1643 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_false); 1644 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_false); 1645 1646 // We don't need to sanity check that *merge_cp_length_p is within 1647 // *merge_cp_p bounds since we have the minimum on-entry check above. 1648 (*merge_cp_length_p) = old_i; 1649 } 1650 1651 // merge_cp_len should be the same as old_cp->length() at this point 1652 // so this trace message is really a "warm-and-breathing" message. 1653 log_debug(redefine, class, constantpool)("after pass 0: merge_cp_len=%d", *merge_cp_length_p); 1654 1655 int scratch_i; // index into scratch_cp 1656 { 1657 // Pass 1a: 1658 // Compare scratch_cp entries to the old_cp entries that we have 1659 // already copied to *merge_cp_p. In this pass, we are eliminating 1660 // exact duplicates (matching entry at same index) so we only 1661 // compare entries in the common indice range. 1662 int increment = 1; 1663 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length()); 1664 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) { 1665 switch (scratch_cp->tag_at(scratch_i).value()) { 1666 case JVM_CONSTANT_Double: 1667 case JVM_CONSTANT_Long: 1668 // double and long take two constant pool entries 1669 increment = 2; 1670 break; 1671 1672 default: 1673 increment = 1; 1674 break; 1675 } 1676 1677 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p, scratch_i); 1678 if (match) { 1679 // found a match at the same index so nothing more to do 1680 continue; 1681 } 1682 1683 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p); 1684 if (found_i != 0) { 1685 guarantee(found_i != scratch_i, 1686 "compare_entry_to() and find_matching_entry() do not agree"); 1687 1688 // Found a matching entry somewhere else in *merge_cp_p so 1689 // just need a mapping entry. 1690 map_index(scratch_cp, scratch_i, found_i); 1691 continue; 1692 } 1693 1694 // No match found so we have to append this entry and any unique 1695 // referenced entries to *merge_cp_p. 1696 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p); 1697 } 1698 } 1699 1700 log_debug(redefine, class, constantpool) 1701 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", 1702 *merge_cp_length_p, scratch_i, _index_map_count); 1703 1704 if (scratch_i < scratch_cp->length()) { 1705 // Pass 1b: 1706 // old_cp is smaller than scratch_cp so there are entries in 1707 // scratch_cp that we have not yet processed. We take care of 1708 // those now. 1709 int increment = 1; 1710 for (; scratch_i < scratch_cp->length(); scratch_i += increment) { 1711 switch (scratch_cp->tag_at(scratch_i).value()) { 1712 case JVM_CONSTANT_Double: 1713 case JVM_CONSTANT_Long: 1714 // double and long take two constant pool entries 1715 increment = 2; 1716 break; 1717 1718 default: 1719 increment = 1; 1720 break; 1721 } 1722 1723 int found_i = 1724 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p); 1725 if (found_i != 0) { 1726 // Found a matching entry somewhere else in *merge_cp_p so 1727 // just need a mapping entry. 1728 map_index(scratch_cp, scratch_i, found_i); 1729 continue; 1730 } 1731 1732 // No match found so we have to append this entry and any unique 1733 // referenced entries to *merge_cp_p. 1734 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p); 1735 } 1736 1737 log_debug(redefine, class, constantpool) 1738 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", 1739 *merge_cp_length_p, scratch_i, _index_map_count); 1740 } 1741 finalize_operands_merge(*merge_cp_p, CHECK_false); 1742 1743 return true; 1744 } // end merge_constant_pools() 1745 1746 1747 // Scoped object to clean up the constant pool(s) created for merging 1748 class MergeCPCleaner { 1749 ClassLoaderData* _loader_data; 1750 ConstantPool* _cp; 1751 ConstantPool* _scratch_cp; 1752 public: 1753 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) : 1754 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(nullptr) {} 1755 ~MergeCPCleaner() { 1756 _loader_data->add_to_deallocate_list(_cp); 1757 if (_scratch_cp != nullptr) { 1758 _loader_data->add_to_deallocate_list(_scratch_cp); 1759 } 1760 } 1761 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; } 1762 }; 1763 1764 // Merge constant pools between the_class and scratch_class and 1765 // potentially rewrite bytecodes in scratch_class to use the merged 1766 // constant pool. 1767 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite( 1768 InstanceKlass* the_class, InstanceKlass* scratch_class, 1769 TRAPS) { 1770 // worst case merged constant pool length is old and new combined 1771 int merge_cp_length = the_class->constants()->length() 1772 + scratch_class->constants()->length(); 1773 1774 // Constant pools are not easily reused so we allocate a new one 1775 // each time. 1776 // merge_cp is created unsafe for concurrent GC processing. It 1777 // should be marked safe before discarding it. Even though 1778 // garbage, if it crosses a card boundary, it may be scanned 1779 // in order to find the start of the first complete object on the card. 1780 ClassLoaderData* loader_data = the_class->class_loader_data(); 1781 ConstantPool* merge_cp_oop = 1782 ConstantPool::allocate(loader_data, 1783 merge_cp_length, 1784 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1785 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop); 1786 1787 HandleMark hm(THREAD); // make sure handles are cleared before 1788 // MergeCPCleaner clears out merge_cp_oop 1789 constantPoolHandle merge_cp(THREAD, merge_cp_oop); 1790 1791 // Get constants() from the old class because it could have been rewritten 1792 // while we were at a safepoint allocating a new constant pool. 1793 constantPoolHandle old_cp(THREAD, the_class->constants()); 1794 constantPoolHandle scratch_cp(THREAD, scratch_class->constants()); 1795 1796 // If the length changed, the class was redefined out from under us. Return 1797 // an error. 1798 if (merge_cp_length != the_class->constants()->length() 1799 + scratch_class->constants()->length()) { 1800 return JVMTI_ERROR_INTERNAL; 1801 } 1802 1803 // Update the version number of the constant pools (may keep scratch_cp) 1804 merge_cp->increment_and_save_version(old_cp->version()); 1805 scratch_cp->increment_and_save_version(old_cp->version()); 1806 1807 ResourceMark rm(THREAD); 1808 _index_map_count = 0; 1809 _index_map_p = new intArray(scratch_cp->length(), scratch_cp->length(), -1); 1810 1811 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands()); 1812 _operands_index_map_count = 0; 1813 int operands_index_map_len = ConstantPool::operand_array_length(scratch_cp->operands()); 1814 _operands_index_map_p = new intArray(operands_index_map_len, operands_index_map_len, -1); 1815 1816 // reference to the cp holder is needed for copy_operands() 1817 merge_cp->set_pool_holder(scratch_class); 1818 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp, 1819 &merge_cp_length, THREAD); 1820 merge_cp->set_pool_holder(nullptr); 1821 1822 if (!result) { 1823 // The merge can fail due to memory allocation failure or due 1824 // to robustness checks. 1825 return JVMTI_ERROR_INTERNAL; 1826 } 1827 1828 // ensure merged constant pool size does not overflow u2 1829 if (merge_cp_length > 0xFFFF) { 1830 log_warning(redefine, class, constantpool)("Merged constant pool overflow: %d entries", merge_cp_length); 1831 return JVMTI_ERROR_INTERNAL; 1832 } 1833 1834 // Set dynamic constants attribute from the original CP. 1835 if (old_cp->has_dynamic_constant()) { 1836 scratch_cp->set_has_dynamic_constant(); 1837 } 1838 1839 log_info(redefine, class, constantpool)("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count); 1840 1841 if (_index_map_count == 0) { 1842 // there is nothing to map between the new and merged constant pools 1843 1844 // Copy attributes from scratch_cp to merge_cp 1845 merge_cp->copy_fields(scratch_cp()); 1846 1847 if (old_cp->length() == scratch_cp->length()) { 1848 // The old and new constant pools are the same length and the 1849 // index map is empty. This means that the three constant pools 1850 // are equivalent (but not the same). Unfortunately, the new 1851 // constant pool has not gone through link resolution nor have 1852 // the new class bytecodes gone through constant pool cache 1853 // rewriting so we can't use the old constant pool with the new 1854 // class. 1855 1856 // toss the merged constant pool at return 1857 } else if (old_cp->length() < scratch_cp->length()) { 1858 // The old constant pool has fewer entries than the new constant 1859 // pool and the index map is empty. This means the new constant 1860 // pool is a superset of the old constant pool. However, the old 1861 // class bytecodes have already gone through constant pool cache 1862 // rewriting so we can't use the new constant pool with the old 1863 // class. 1864 1865 // toss the merged constant pool at return 1866 } else { 1867 // The old constant pool has more entries than the new constant 1868 // pool and the index map is empty. This means that both the old 1869 // and merged constant pools are supersets of the new constant 1870 // pool. 1871 1872 // Replace the new constant pool with a shrunken copy of the 1873 // merged constant pool 1874 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, 1875 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1876 // The new constant pool replaces scratch_cp so have cleaner clean it up. 1877 // It can't be cleaned up while there are handles to it. 1878 cp_cleaner.add_scratch_cp(scratch_cp()); 1879 } 1880 } else { 1881 if (log_is_enabled(Trace, redefine, class, constantpool)) { 1882 // don't want to loop unless we are tracing 1883 int count = 0; 1884 for (int i = 1; i < _index_map_p->length(); i++) { 1885 int value = _index_map_p->at(i); 1886 1887 if (value != -1) { 1888 log_trace(redefine, class, constantpool)("index_map[%d]: old=%d new=%d", count, i, value); 1889 count++; 1890 } 1891 } 1892 } 1893 1894 // We have entries mapped between the new and merged constant pools 1895 // so we have to rewrite some constant pool references. 1896 if (!rewrite_cp_refs(scratch_class)) { 1897 return JVMTI_ERROR_INTERNAL; 1898 } 1899 1900 // Copy attributes from scratch_cp to merge_cp (should be done after rewrite_cp_refs()) 1901 merge_cp->copy_fields(scratch_cp()); 1902 1903 // Replace the new constant pool with a shrunken copy of the 1904 // merged constant pool so now the rewritten bytecodes have 1905 // valid references; the previous new constant pool will get 1906 // GCed. 1907 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, 1908 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1909 // The new constant pool replaces scratch_cp so have cleaner clean it up. 1910 // It can't be cleaned up while there are handles to it. 1911 cp_cleaner.add_scratch_cp(scratch_cp()); 1912 } 1913 1914 return JVMTI_ERROR_NONE; 1915 } // end merge_cp_and_rewrite() 1916 1917 1918 // Rewrite constant pool references in klass scratch_class. 1919 bool VM_RedefineClasses::rewrite_cp_refs(InstanceKlass* scratch_class) { 1920 1921 // rewrite constant pool references in the nest attributes: 1922 if (!rewrite_cp_refs_in_nest_attributes(scratch_class)) { 1923 // propagate failure back to caller 1924 return false; 1925 } 1926 1927 // rewrite constant pool references in the Record attribute: 1928 if (!rewrite_cp_refs_in_record_attribute(scratch_class)) { 1929 // propagate failure back to caller 1930 return false; 1931 } 1932 1933 // rewrite constant pool references in the PermittedSubclasses attribute: 1934 if (!rewrite_cp_refs_in_permitted_subclasses_attribute(scratch_class)) { 1935 // propagate failure back to caller 1936 return false; 1937 } 1938 1939 // rewrite constant pool references in the LoadableDescriptors attribute: 1940 if (!rewrite_cp_refs_in_loadable_descriptors_attribute(scratch_class)) { 1941 // propagate failure back to caller 1942 return false; 1943 } 1944 1945 // rewrite constant pool references in the methods: 1946 if (!rewrite_cp_refs_in_methods(scratch_class)) { 1947 // propagate failure back to caller 1948 return false; 1949 } 1950 1951 // rewrite constant pool references in the class_annotations: 1952 if (!rewrite_cp_refs_in_class_annotations(scratch_class)) { 1953 // propagate failure back to caller 1954 return false; 1955 } 1956 1957 // rewrite constant pool references in the fields_annotations: 1958 if (!rewrite_cp_refs_in_fields_annotations(scratch_class)) { 1959 // propagate failure back to caller 1960 return false; 1961 } 1962 1963 // rewrite constant pool references in the methods_annotations: 1964 if (!rewrite_cp_refs_in_methods_annotations(scratch_class)) { 1965 // propagate failure back to caller 1966 return false; 1967 } 1968 1969 // rewrite constant pool references in the methods_parameter_annotations: 1970 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class)) { 1971 // propagate failure back to caller 1972 return false; 1973 } 1974 1975 // rewrite constant pool references in the methods_default_annotations: 1976 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class)) { 1977 // propagate failure back to caller 1978 return false; 1979 } 1980 1981 // rewrite constant pool references in the class_type_annotations: 1982 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class)) { 1983 // propagate failure back to caller 1984 return false; 1985 } 1986 1987 // rewrite constant pool references in the fields_type_annotations: 1988 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class)) { 1989 // propagate failure back to caller 1990 return false; 1991 } 1992 1993 // rewrite constant pool references in the methods_type_annotations: 1994 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class)) { 1995 // propagate failure back to caller 1996 return false; 1997 } 1998 1999 // There can be type annotations in the Code part of a method_info attribute. 2000 // These annotations are not accessible, even by reflection. 2001 // Currently they are not even parsed by the ClassFileParser. 2002 // If runtime access is added they will also need to be rewritten. 2003 2004 // rewrite source file name index: 2005 u2 source_file_name_idx = scratch_class->source_file_name_index(); 2006 if (source_file_name_idx != 0) { 2007 u2 new_source_file_name_idx = find_new_index(source_file_name_idx); 2008 if (new_source_file_name_idx != 0) { 2009 scratch_class->set_source_file_name_index(new_source_file_name_idx); 2010 } 2011 } 2012 2013 // rewrite class generic signature index: 2014 u2 generic_signature_index = scratch_class->generic_signature_index(); 2015 if (generic_signature_index != 0) { 2016 u2 new_generic_signature_index = find_new_index(generic_signature_index); 2017 if (new_generic_signature_index != 0) { 2018 scratch_class->set_generic_signature_index(new_generic_signature_index); 2019 } 2020 } 2021 2022 return true; 2023 } // end rewrite_cp_refs() 2024 2025 // Rewrite constant pool references in the NestHost and NestMembers attributes. 2026 bool VM_RedefineClasses::rewrite_cp_refs_in_nest_attributes( 2027 InstanceKlass* scratch_class) { 2028 2029 u2 cp_index = scratch_class->nest_host_index(); 2030 if (cp_index != 0) { 2031 scratch_class->set_nest_host_index(find_new_index(cp_index)); 2032 } 2033 Array<u2>* nest_members = scratch_class->nest_members(); 2034 for (int i = 0; i < nest_members->length(); i++) { 2035 u2 cp_index = nest_members->at(i); 2036 nest_members->at_put(i, find_new_index(cp_index)); 2037 } 2038 return true; 2039 } 2040 2041 // Rewrite constant pool references in the Record attribute. 2042 bool VM_RedefineClasses::rewrite_cp_refs_in_record_attribute(InstanceKlass* scratch_class) { 2043 Array<RecordComponent*>* components = scratch_class->record_components(); 2044 if (components != nullptr) { 2045 for (int i = 0; i < components->length(); i++) { 2046 RecordComponent* component = components->at(i); 2047 u2 cp_index = component->name_index(); 2048 component->set_name_index(find_new_index(cp_index)); 2049 cp_index = component->descriptor_index(); 2050 component->set_descriptor_index(find_new_index(cp_index)); 2051 cp_index = component->generic_signature_index(); 2052 if (cp_index != 0) { 2053 component->set_generic_signature_index(find_new_index(cp_index)); 2054 } 2055 2056 AnnotationArray* annotations = component->annotations(); 2057 if (annotations != nullptr && annotations->length() != 0) { 2058 int byte_i = 0; // byte index into annotations 2059 if (!rewrite_cp_refs_in_annotations_typeArray(annotations, byte_i)) { 2060 log_debug(redefine, class, annotation)("bad record_component_annotations at %d", i); 2061 // propagate failure back to caller 2062 return false; 2063 } 2064 } 2065 2066 AnnotationArray* type_annotations = component->type_annotations(); 2067 if (type_annotations != nullptr && type_annotations->length() != 0) { 2068 int byte_i = 0; // byte index into annotations 2069 if (!rewrite_cp_refs_in_annotations_typeArray(type_annotations, byte_i)) { 2070 log_debug(redefine, class, annotation)("bad record_component_type_annotations at %d", i); 2071 // propagate failure back to caller 2072 return false; 2073 } 2074 } 2075 } 2076 } 2077 return true; 2078 } 2079 2080 // Rewrite constant pool references in the PermittedSubclasses attribute. 2081 bool VM_RedefineClasses::rewrite_cp_refs_in_permitted_subclasses_attribute( 2082 InstanceKlass* scratch_class) { 2083 2084 Array<u2>* permitted_subclasses = scratch_class->permitted_subclasses(); 2085 assert(permitted_subclasses != nullptr, "unexpected null permitted_subclasses"); 2086 for (int i = 0; i < permitted_subclasses->length(); i++) { 2087 u2 cp_index = permitted_subclasses->at(i); 2088 permitted_subclasses->at_put(i, find_new_index(cp_index)); 2089 } 2090 return true; 2091 } 2092 2093 // Rewrite constant pool references in the LoadableDescriptors attribute. 2094 bool VM_RedefineClasses::rewrite_cp_refs_in_loadable_descriptors_attribute( 2095 InstanceKlass* scratch_class) { 2096 2097 Array<u2>* loadable_descriptors = scratch_class->loadable_descriptors(); 2098 assert(loadable_descriptors != nullptr, "unexpected null loadable_descriptors"); 2099 for (int i = 0; i < loadable_descriptors->length(); i++) { 2100 u2 cp_index = loadable_descriptors->at(i); 2101 loadable_descriptors->at_put(i, find_new_index(cp_index)); 2102 } 2103 return true; 2104 } 2105 2106 // Rewrite constant pool references in the methods. 2107 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(InstanceKlass* scratch_class) { 2108 2109 Array<Method*>* methods = scratch_class->methods(); 2110 2111 if (methods == nullptr || methods->length() == 0) { 2112 // no methods so nothing to do 2113 return true; 2114 } 2115 2116 JavaThread* THREAD = JavaThread::current(); // For exception macros. 2117 ExceptionMark em(THREAD); 2118 2119 // rewrite constant pool references in the methods: 2120 for (int i = methods->length() - 1; i >= 0; i--) { 2121 methodHandle method(THREAD, methods->at(i)); 2122 methodHandle new_method; 2123 rewrite_cp_refs_in_method(method, &new_method, THREAD); 2124 if (!new_method.is_null()) { 2125 // the method has been replaced so save the new method version 2126 // even in the case of an exception. original method is on the 2127 // deallocation list. 2128 methods->at_put(i, new_method()); 2129 } 2130 if (HAS_PENDING_EXCEPTION) { 2131 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 2132 log_info(redefine, class, load, exceptions)("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string()); 2133 // Need to clear pending exception here as the super caller sets 2134 // the JVMTI_ERROR_INTERNAL if the returned value is false. 2135 CLEAR_PENDING_EXCEPTION; 2136 return false; 2137 } 2138 } 2139 2140 return true; 2141 } 2142 2143 2144 // Rewrite constant pool references in the specific method. This code 2145 // was adapted from Rewriter::rewrite_method(). 2146 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method, 2147 methodHandle *new_method_p, TRAPS) { 2148 2149 *new_method_p = methodHandle(); // default is no new method 2150 2151 // We cache a pointer to the bytecodes here in code_base. If GC 2152 // moves the Method*, then the bytecodes will also move which 2153 // will likely cause a crash. We create a NoSafepointVerifier 2154 // object to detect whether we pass a possible safepoint in this 2155 // code block. 2156 NoSafepointVerifier nsv; 2157 2158 // Bytecodes and their length 2159 address code_base = method->code_base(); 2160 int code_length = method->code_size(); 2161 2162 int bc_length; 2163 for (int bci = 0; bci < code_length; bci += bc_length) { 2164 address bcp = code_base + bci; 2165 Bytecodes::Code c = (Bytecodes::Code)(*bcp); 2166 2167 bc_length = Bytecodes::length_for(c); 2168 if (bc_length == 0) { 2169 // More complicated bytecodes report a length of zero so 2170 // we have to try again a slightly different way. 2171 bc_length = Bytecodes::length_at(method(), bcp); 2172 } 2173 2174 assert(bc_length != 0, "impossible bytecode length"); 2175 2176 switch (c) { 2177 case Bytecodes::_ldc: 2178 { 2179 u1 cp_index = *(bcp + 1); 2180 u2 new_index = find_new_index(cp_index); 2181 2182 if (StressLdcRewrite && new_index == 0) { 2183 // If we are stressing ldc -> ldc_w rewriting, then we 2184 // always need a new_index value. 2185 new_index = cp_index; 2186 } 2187 if (new_index != 0) { 2188 // the original index is mapped so we have more work to do 2189 if (!StressLdcRewrite && new_index <= max_jubyte) { 2190 // The new value can still use ldc instead of ldc_w 2191 // unless we are trying to stress ldc -> ldc_w rewriting 2192 log_trace(redefine, class, constantpool) 2193 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index); 2194 // We checked that new_index fits in a u1 so this cast is safe 2195 *(bcp + 1) = (u1)new_index; 2196 } else { 2197 log_trace(redefine, class, constantpool) 2198 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index); 2199 // the new value needs ldc_w instead of ldc 2200 u_char inst_buffer[4]; // max instruction size is 4 bytes 2201 bcp = (address)inst_buffer; 2202 // construct new instruction sequence 2203 *bcp = Bytecodes::_ldc_w; 2204 bcp++; 2205 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w. 2206 // See comment below for difference between put_Java_u2() 2207 // and put_native_u2(). 2208 Bytes::put_Java_u2(bcp, new_index); 2209 2210 Relocator rc(method, nullptr /* no RelocatorListener needed */); 2211 methodHandle m; 2212 { 2213 PauseNoSafepointVerifier pnsv(&nsv); 2214 2215 // ldc is 2 bytes and ldc_w is 3 bytes 2216 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK); 2217 } 2218 2219 // return the new method so that the caller can update 2220 // the containing class 2221 *new_method_p = method = m; 2222 // switch our bytecode processing loop from the old method 2223 // to the new method 2224 code_base = method->code_base(); 2225 code_length = method->code_size(); 2226 bcp = code_base + bci; 2227 c = (Bytecodes::Code)(*bcp); 2228 bc_length = Bytecodes::length_for(c); 2229 assert(bc_length != 0, "sanity check"); 2230 } // end we need ldc_w instead of ldc 2231 } // end if there is a mapped index 2232 } break; 2233 2234 // these bytecodes have a two-byte constant pool index 2235 case Bytecodes::_anewarray : // fall through 2236 case Bytecodes::_checkcast : // fall through 2237 case Bytecodes::_getfield : // fall through 2238 case Bytecodes::_getstatic : // fall through 2239 case Bytecodes::_instanceof : // fall through 2240 case Bytecodes::_invokedynamic : // fall through 2241 case Bytecodes::_invokeinterface: // fall through 2242 case Bytecodes::_invokespecial : // fall through 2243 case Bytecodes::_invokestatic : // fall through 2244 case Bytecodes::_invokevirtual : // fall through 2245 case Bytecodes::_ldc_w : // fall through 2246 case Bytecodes::_ldc2_w : // fall through 2247 case Bytecodes::_multianewarray : // fall through 2248 case Bytecodes::_new : // fall through 2249 case Bytecodes::_putfield : // fall through 2250 case Bytecodes::_putstatic : 2251 { 2252 address p = bcp + 1; 2253 int cp_index = Bytes::get_Java_u2(p); 2254 u2 new_index = find_new_index(cp_index); 2255 if (new_index != 0) { 2256 // the original index is mapped so update w/ new value 2257 log_trace(redefine, class, constantpool) 2258 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),p2i(bcp), cp_index, new_index); 2259 // Rewriter::rewrite_method() uses put_native_u2() in this 2260 // situation because it is reusing the constant pool index 2261 // location for a native index into the ConstantPoolCache. 2262 // Since we are updating the constant pool index prior to 2263 // verification and ConstantPoolCache initialization, we 2264 // need to keep the new index in Java byte order. 2265 Bytes::put_Java_u2(p, new_index); 2266 } 2267 } break; 2268 default: 2269 break; 2270 } 2271 } // end for each bytecode 2272 } // end rewrite_cp_refs_in_method() 2273 2274 2275 // Rewrite constant pool references in the class_annotations field. 2276 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(InstanceKlass* scratch_class) { 2277 2278 AnnotationArray* class_annotations = scratch_class->class_annotations(); 2279 if (class_annotations == nullptr || class_annotations->length() == 0) { 2280 // no class_annotations so nothing to do 2281 return true; 2282 } 2283 2284 log_debug(redefine, class, annotation)("class_annotations length=%d", class_annotations->length()); 2285 2286 int byte_i = 0; // byte index into class_annotations 2287 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i); 2288 } 2289 2290 2291 // Rewrite constant pool references in an annotations typeArray. This 2292 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute 2293 // that is described in section 4.8.15 of the 2nd-edition of the VM spec: 2294 // 2295 // annotations_typeArray { 2296 // u2 num_annotations; 2297 // annotation annotations[num_annotations]; 2298 // } 2299 // 2300 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray( 2301 AnnotationArray* annotations_typeArray, int &byte_i_ref) { 2302 2303 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2304 // not enough room for num_annotations field 2305 log_debug(redefine, class, annotation)("length() is too small for num_annotations field"); 2306 return false; 2307 } 2308 2309 u2 num_annotations = Bytes::get_Java_u2((address) 2310 annotations_typeArray->adr_at(byte_i_ref)); 2311 byte_i_ref += 2; 2312 2313 log_debug(redefine, class, annotation)("num_annotations=%d", num_annotations); 2314 2315 int calc_num_annotations = 0; 2316 for (; calc_num_annotations < num_annotations; calc_num_annotations++) { 2317 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, byte_i_ref)) { 2318 log_debug(redefine, class, annotation)("bad annotation_struct at %d", calc_num_annotations); 2319 // propagate failure back to caller 2320 return false; 2321 } 2322 } 2323 assert(num_annotations == calc_num_annotations, "sanity check"); 2324 2325 return true; 2326 } // end rewrite_cp_refs_in_annotations_typeArray() 2327 2328 2329 // Rewrite constant pool references in the annotation struct portion of 2330 // an annotations_typeArray. This "structure" is from section 4.8.15 of 2331 // the 2nd-edition of the VM spec: 2332 // 2333 // struct annotation { 2334 // u2 type_index; 2335 // u2 num_element_value_pairs; 2336 // { 2337 // u2 element_name_index; 2338 // element_value value; 2339 // } element_value_pairs[num_element_value_pairs]; 2340 // } 2341 // 2342 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct( 2343 AnnotationArray* annotations_typeArray, int &byte_i_ref) { 2344 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) { 2345 // not enough room for smallest annotation_struct 2346 log_debug(redefine, class, annotation)("length() is too small for annotation_struct"); 2347 return false; 2348 } 2349 2350 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray, 2351 byte_i_ref, "type_index"); 2352 2353 u2 num_element_value_pairs = Bytes::get_Java_u2((address) 2354 annotations_typeArray->adr_at(byte_i_ref)); 2355 byte_i_ref += 2; 2356 2357 log_debug(redefine, class, annotation) 2358 ("type_index=%d num_element_value_pairs=%d", type_index, num_element_value_pairs); 2359 2360 int calc_num_element_value_pairs = 0; 2361 for (; calc_num_element_value_pairs < num_element_value_pairs; 2362 calc_num_element_value_pairs++) { 2363 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2364 // not enough room for another element_name_index, let alone 2365 // the rest of another component 2366 log_debug(redefine, class, annotation)("length() is too small for element_name_index"); 2367 return false; 2368 } 2369 2370 u2 element_name_index = rewrite_cp_ref_in_annotation_data( 2371 annotations_typeArray, byte_i_ref, 2372 "element_name_index"); 2373 2374 log_debug(redefine, class, annotation)("element_name_index=%d", element_name_index); 2375 2376 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, byte_i_ref)) { 2377 log_debug(redefine, class, annotation)("bad element_value at %d", calc_num_element_value_pairs); 2378 // propagate failure back to caller 2379 return false; 2380 } 2381 } // end for each component 2382 assert(num_element_value_pairs == calc_num_element_value_pairs, 2383 "sanity check"); 2384 2385 return true; 2386 } // end rewrite_cp_refs_in_annotation_struct() 2387 2388 2389 // Rewrite a constant pool reference at the current position in 2390 // annotations_typeArray if needed. Returns the original constant 2391 // pool reference if a rewrite was not needed or the new constant 2392 // pool reference if a rewrite was needed. 2393 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data( 2394 AnnotationArray* annotations_typeArray, int &byte_i_ref, 2395 const char * trace_mesg) { 2396 2397 address cp_index_addr = (address) 2398 annotations_typeArray->adr_at(byte_i_ref); 2399 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr); 2400 u2 new_cp_index = find_new_index(old_cp_index); 2401 if (new_cp_index != 0) { 2402 log_debug(redefine, class, annotation)("mapped old %s=%d", trace_mesg, old_cp_index); 2403 Bytes::put_Java_u2(cp_index_addr, new_cp_index); 2404 old_cp_index = new_cp_index; 2405 } 2406 byte_i_ref += 2; 2407 return old_cp_index; 2408 } 2409 2410 2411 // Rewrite constant pool references in the element_value portion of an 2412 // annotations_typeArray. This "structure" is from section 4.8.15.1 of 2413 // the 2nd-edition of the VM spec: 2414 // 2415 // struct element_value { 2416 // u1 tag; 2417 // union { 2418 // u2 const_value_index; 2419 // { 2420 // u2 type_name_index; 2421 // u2 const_name_index; 2422 // } enum_const_value; 2423 // u2 class_info_index; 2424 // annotation annotation_value; 2425 // struct { 2426 // u2 num_values; 2427 // element_value values[num_values]; 2428 // } array_value; 2429 // } value; 2430 // } 2431 // 2432 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value( 2433 AnnotationArray* annotations_typeArray, int &byte_i_ref) { 2434 2435 if ((byte_i_ref + 1) > annotations_typeArray->length()) { 2436 // not enough room for a tag let alone the rest of an element_value 2437 log_debug(redefine, class, annotation)("length() is too small for a tag"); 2438 return false; 2439 } 2440 2441 u1 tag = annotations_typeArray->at(byte_i_ref); 2442 byte_i_ref++; 2443 log_debug(redefine, class, annotation)("tag='%c'", tag); 2444 2445 switch (tag) { 2446 // These BaseType tag values are from Table 4.2 in VM spec: 2447 case JVM_SIGNATURE_BYTE: 2448 case JVM_SIGNATURE_CHAR: 2449 case JVM_SIGNATURE_DOUBLE: 2450 case JVM_SIGNATURE_FLOAT: 2451 case JVM_SIGNATURE_INT: 2452 case JVM_SIGNATURE_LONG: 2453 case JVM_SIGNATURE_SHORT: 2454 case JVM_SIGNATURE_BOOLEAN: 2455 2456 // The remaining tag values are from Table 4.8 in the 2nd-edition of 2457 // the VM spec: 2458 case 's': 2459 { 2460 // For the above tag values (including the BaseType values), 2461 // value.const_value_index is right union field. 2462 2463 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2464 // not enough room for a const_value_index 2465 log_debug(redefine, class, annotation)("length() is too small for a const_value_index"); 2466 return false; 2467 } 2468 2469 u2 const_value_index = rewrite_cp_ref_in_annotation_data( 2470 annotations_typeArray, byte_i_ref, 2471 "const_value_index"); 2472 2473 log_debug(redefine, class, annotation)("const_value_index=%d", const_value_index); 2474 } break; 2475 2476 case 'e': 2477 { 2478 // for the above tag value, value.enum_const_value is right union field 2479 2480 if ((byte_i_ref + 4) > annotations_typeArray->length()) { 2481 // not enough room for a enum_const_value 2482 log_debug(redefine, class, annotation)("length() is too small for a enum_const_value"); 2483 return false; 2484 } 2485 2486 u2 type_name_index = rewrite_cp_ref_in_annotation_data( 2487 annotations_typeArray, byte_i_ref, 2488 "type_name_index"); 2489 2490 u2 const_name_index = rewrite_cp_ref_in_annotation_data( 2491 annotations_typeArray, byte_i_ref, 2492 "const_name_index"); 2493 2494 log_debug(redefine, class, annotation) 2495 ("type_name_index=%d const_name_index=%d", type_name_index, const_name_index); 2496 } break; 2497 2498 case 'c': 2499 { 2500 // for the above tag value, value.class_info_index is right union field 2501 2502 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2503 // not enough room for a class_info_index 2504 log_debug(redefine, class, annotation)("length() is too small for a class_info_index"); 2505 return false; 2506 } 2507 2508 u2 class_info_index = rewrite_cp_ref_in_annotation_data( 2509 annotations_typeArray, byte_i_ref, 2510 "class_info_index"); 2511 2512 log_debug(redefine, class, annotation)("class_info_index=%d", class_info_index); 2513 } break; 2514 2515 case '@': 2516 // For the above tag value, value.attr_value is the right union 2517 // field. This is a nested annotation. 2518 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, byte_i_ref)) { 2519 // propagate failure back to caller 2520 return false; 2521 } 2522 break; 2523 2524 case JVM_SIGNATURE_ARRAY: 2525 { 2526 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2527 // not enough room for a num_values field 2528 log_debug(redefine, class, annotation)("length() is too small for a num_values field"); 2529 return false; 2530 } 2531 2532 // For the above tag value, value.array_value is the right union 2533 // field. This is an array of nested element_value. 2534 u2 num_values = Bytes::get_Java_u2((address) 2535 annotations_typeArray->adr_at(byte_i_ref)); 2536 byte_i_ref += 2; 2537 log_debug(redefine, class, annotation)("num_values=%d", num_values); 2538 2539 int calc_num_values = 0; 2540 for (; calc_num_values < num_values; calc_num_values++) { 2541 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, byte_i_ref)) { 2542 log_debug(redefine, class, annotation)("bad nested element_value at %d", calc_num_values); 2543 // propagate failure back to caller 2544 return false; 2545 } 2546 } 2547 assert(num_values == calc_num_values, "sanity check"); 2548 } break; 2549 2550 default: 2551 log_debug(redefine, class, annotation)("bad tag=0x%x", tag); 2552 return false; 2553 } // end decode tag field 2554 2555 return true; 2556 } // end rewrite_cp_refs_in_element_value() 2557 2558 2559 // Rewrite constant pool references in a fields_annotations field. 2560 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations( 2561 InstanceKlass* scratch_class) { 2562 2563 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations(); 2564 2565 if (fields_annotations == nullptr || fields_annotations->length() == 0) { 2566 // no fields_annotations so nothing to do 2567 return true; 2568 } 2569 2570 log_debug(redefine, class, annotation)("fields_annotations length=%d", fields_annotations->length()); 2571 2572 for (int i = 0; i < fields_annotations->length(); i++) { 2573 AnnotationArray* field_annotations = fields_annotations->at(i); 2574 if (field_annotations == nullptr || field_annotations->length() == 0) { 2575 // this field does not have any annotations so skip it 2576 continue; 2577 } 2578 2579 int byte_i = 0; // byte index into field_annotations 2580 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i)) { 2581 log_debug(redefine, class, annotation)("bad field_annotations at %d", i); 2582 // propagate failure back to caller 2583 return false; 2584 } 2585 } 2586 2587 return true; 2588 } // end rewrite_cp_refs_in_fields_annotations() 2589 2590 2591 // Rewrite constant pool references in a methods_annotations field. 2592 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations( 2593 InstanceKlass* scratch_class) { 2594 2595 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2596 Method* m = scratch_class->methods()->at(i); 2597 AnnotationArray* method_annotations = m->constMethod()->method_annotations(); 2598 2599 if (method_annotations == nullptr || method_annotations->length() == 0) { 2600 // this method does not have any annotations so skip it 2601 continue; 2602 } 2603 2604 int byte_i = 0; // byte index into method_annotations 2605 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i)) { 2606 log_debug(redefine, class, annotation)("bad method_annotations at %d", i); 2607 // propagate failure back to caller 2608 return false; 2609 } 2610 } 2611 2612 return true; 2613 } // end rewrite_cp_refs_in_methods_annotations() 2614 2615 2616 // Rewrite constant pool references in a methods_parameter_annotations 2617 // field. This "structure" is adapted from the 2618 // RuntimeVisibleParameterAnnotations_attribute described in section 2619 // 4.8.17 of the 2nd-edition of the VM spec: 2620 // 2621 // methods_parameter_annotations_typeArray { 2622 // u1 num_parameters; 2623 // { 2624 // u2 num_annotations; 2625 // annotation annotations[num_annotations]; 2626 // } parameter_annotations[num_parameters]; 2627 // } 2628 // 2629 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations( 2630 InstanceKlass* scratch_class) { 2631 2632 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2633 Method* m = scratch_class->methods()->at(i); 2634 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations(); 2635 if (method_parameter_annotations == nullptr 2636 || method_parameter_annotations->length() == 0) { 2637 // this method does not have any parameter annotations so skip it 2638 continue; 2639 } 2640 2641 if (method_parameter_annotations->length() < 1) { 2642 // not enough room for a num_parameters field 2643 log_debug(redefine, class, annotation)("length() is too small for a num_parameters field at %d", i); 2644 return false; 2645 } 2646 2647 int byte_i = 0; // byte index into method_parameter_annotations 2648 2649 u1 num_parameters = method_parameter_annotations->at(byte_i); 2650 byte_i++; 2651 2652 log_debug(redefine, class, annotation)("num_parameters=%d", num_parameters); 2653 2654 int calc_num_parameters = 0; 2655 for (; calc_num_parameters < num_parameters; calc_num_parameters++) { 2656 if (!rewrite_cp_refs_in_annotations_typeArray(method_parameter_annotations, byte_i)) { 2657 log_debug(redefine, class, annotation)("bad method_parameter_annotations at %d", calc_num_parameters); 2658 // propagate failure back to caller 2659 return false; 2660 } 2661 } 2662 assert(num_parameters == calc_num_parameters, "sanity check"); 2663 } 2664 2665 return true; 2666 } // end rewrite_cp_refs_in_methods_parameter_annotations() 2667 2668 2669 // Rewrite constant pool references in a methods_default_annotations 2670 // field. This "structure" is adapted from the AnnotationDefault_attribute 2671 // that is described in section 4.8.19 of the 2nd-edition of the VM spec: 2672 // 2673 // methods_default_annotations_typeArray { 2674 // element_value default_value; 2675 // } 2676 // 2677 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations( 2678 InstanceKlass* scratch_class) { 2679 2680 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2681 Method* m = scratch_class->methods()->at(i); 2682 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations(); 2683 if (method_default_annotations == nullptr 2684 || method_default_annotations->length() == 0) { 2685 // this method does not have any default annotations so skip it 2686 continue; 2687 } 2688 2689 int byte_i = 0; // byte index into method_default_annotations 2690 2691 if (!rewrite_cp_refs_in_element_value( 2692 method_default_annotations, byte_i)) { 2693 log_debug(redefine, class, annotation)("bad default element_value at %d", i); 2694 // propagate failure back to caller 2695 return false; 2696 } 2697 } 2698 2699 return true; 2700 } // end rewrite_cp_refs_in_methods_default_annotations() 2701 2702 2703 // Rewrite constant pool references in a class_type_annotations field. 2704 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations( 2705 InstanceKlass* scratch_class) { 2706 2707 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations(); 2708 if (class_type_annotations == nullptr || class_type_annotations->length() == 0) { 2709 // no class_type_annotations so nothing to do 2710 return true; 2711 } 2712 2713 log_debug(redefine, class, annotation)("class_type_annotations length=%d", class_type_annotations->length()); 2714 2715 int byte_i = 0; // byte index into class_type_annotations 2716 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations, 2717 byte_i, "ClassFile"); 2718 } // end rewrite_cp_refs_in_class_type_annotations() 2719 2720 2721 // Rewrite constant pool references in a fields_type_annotations field. 2722 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations(InstanceKlass* scratch_class) { 2723 2724 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations(); 2725 if (fields_type_annotations == nullptr || fields_type_annotations->length() == 0) { 2726 // no fields_type_annotations so nothing to do 2727 return true; 2728 } 2729 2730 log_debug(redefine, class, annotation)("fields_type_annotations length=%d", fields_type_annotations->length()); 2731 2732 for (int i = 0; i < fields_type_annotations->length(); i++) { 2733 AnnotationArray* field_type_annotations = fields_type_annotations->at(i); 2734 if (field_type_annotations == nullptr || field_type_annotations->length() == 0) { 2735 // this field does not have any annotations so skip it 2736 continue; 2737 } 2738 2739 int byte_i = 0; // byte index into field_type_annotations 2740 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations, 2741 byte_i, "field_info")) { 2742 log_debug(redefine, class, annotation)("bad field_type_annotations at %d", i); 2743 // propagate failure back to caller 2744 return false; 2745 } 2746 } 2747 2748 return true; 2749 } // end rewrite_cp_refs_in_fields_type_annotations() 2750 2751 2752 // Rewrite constant pool references in a methods_type_annotations field. 2753 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations( 2754 InstanceKlass* scratch_class) { 2755 2756 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2757 Method* m = scratch_class->methods()->at(i); 2758 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations(); 2759 2760 if (method_type_annotations == nullptr || method_type_annotations->length() == 0) { 2761 // this method does not have any annotations so skip it 2762 continue; 2763 } 2764 2765 log_debug(redefine, class, annotation)("methods type_annotations length=%d", method_type_annotations->length()); 2766 2767 int byte_i = 0; // byte index into method_type_annotations 2768 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations, 2769 byte_i, "method_info")) { 2770 log_debug(redefine, class, annotation)("bad method_type_annotations at %d", i); 2771 // propagate failure back to caller 2772 return false; 2773 } 2774 } 2775 2776 return true; 2777 } // end rewrite_cp_refs_in_methods_type_annotations() 2778 2779 2780 // Rewrite constant pool references in a type_annotations 2781 // field. This "structure" is adapted from the 2782 // RuntimeVisibleTypeAnnotations_attribute described in 2783 // section 4.7.20 of the Java SE 8 Edition of the VM spec: 2784 // 2785 // type_annotations_typeArray { 2786 // u2 num_annotations; 2787 // type_annotation annotations[num_annotations]; 2788 // } 2789 // 2790 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray( 2791 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2792 const char * location_mesg) { 2793 2794 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2795 // not enough room for num_annotations field 2796 log_debug(redefine, class, annotation)("length() is too small for num_annotations field"); 2797 return false; 2798 } 2799 2800 u2 num_annotations = Bytes::get_Java_u2((address) 2801 type_annotations_typeArray->adr_at(byte_i_ref)); 2802 byte_i_ref += 2; 2803 2804 log_debug(redefine, class, annotation)("num_type_annotations=%d", num_annotations); 2805 2806 int calc_num_annotations = 0; 2807 for (; calc_num_annotations < num_annotations; calc_num_annotations++) { 2808 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray, 2809 byte_i_ref, location_mesg)) { 2810 log_debug(redefine, class, annotation)("bad type_annotation_struct at %d", calc_num_annotations); 2811 // propagate failure back to caller 2812 return false; 2813 } 2814 } 2815 assert(num_annotations == calc_num_annotations, "sanity check"); 2816 2817 if (byte_i_ref != type_annotations_typeArray->length()) { 2818 log_debug(redefine, class, annotation) 2819 ("read wrong amount of bytes at end of processing type_annotations_typeArray (%d of %d bytes were read)", 2820 byte_i_ref, type_annotations_typeArray->length()); 2821 return false; 2822 } 2823 2824 return true; 2825 } // end rewrite_cp_refs_in_type_annotations_typeArray() 2826 2827 2828 // Rewrite constant pool references in a type_annotation 2829 // field. This "structure" is adapted from the 2830 // RuntimeVisibleTypeAnnotations_attribute described in 2831 // section 4.7.20 of the Java SE 8 Edition of the VM spec: 2832 // 2833 // type_annotation { 2834 // u1 target_type; 2835 // union { 2836 // type_parameter_target; 2837 // supertype_target; 2838 // type_parameter_bound_target; 2839 // empty_target; 2840 // method_formal_parameter_target; 2841 // throws_target; 2842 // localvar_target; 2843 // catch_target; 2844 // offset_target; 2845 // type_argument_target; 2846 // } target_info; 2847 // type_path target_path; 2848 // annotation anno; 2849 // } 2850 // 2851 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct( 2852 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2853 const char * location_mesg) { 2854 2855 if (!skip_type_annotation_target(type_annotations_typeArray, 2856 byte_i_ref, location_mesg)) { 2857 return false; 2858 } 2859 2860 if (!skip_type_annotation_type_path(type_annotations_typeArray, byte_i_ref)) { 2861 return false; 2862 } 2863 2864 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray, byte_i_ref)) { 2865 return false; 2866 } 2867 2868 return true; 2869 } // end rewrite_cp_refs_in_type_annotation_struct() 2870 2871 2872 // Read, verify and skip over the target_type and target_info part 2873 // so that rewriting can continue in the later parts of the struct. 2874 // 2875 // u1 target_type; 2876 // union { 2877 // type_parameter_target; 2878 // supertype_target; 2879 // type_parameter_bound_target; 2880 // empty_target; 2881 // method_formal_parameter_target; 2882 // throws_target; 2883 // localvar_target; 2884 // catch_target; 2885 // offset_target; 2886 // type_argument_target; 2887 // } target_info; 2888 // 2889 bool VM_RedefineClasses::skip_type_annotation_target( 2890 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2891 const char * location_mesg) { 2892 2893 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2894 // not enough room for a target_type let alone the rest of a type_annotation 2895 log_debug(redefine, class, annotation)("length() is too small for a target_type"); 2896 return false; 2897 } 2898 2899 u1 target_type = type_annotations_typeArray->at(byte_i_ref); 2900 byte_i_ref += 1; 2901 log_debug(redefine, class, annotation)("target_type=0x%.2x", target_type); 2902 log_debug(redefine, class, annotation)("location=%s", location_mesg); 2903 2904 // Skip over target_info 2905 switch (target_type) { 2906 case 0x00: 2907 // kind: type parameter declaration of generic class or interface 2908 // location: ClassFile 2909 case 0x01: 2910 // kind: type parameter declaration of generic method or constructor 2911 // location: method_info 2912 2913 { 2914 // struct: 2915 // type_parameter_target { 2916 // u1 type_parameter_index; 2917 // } 2918 // 2919 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2920 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_target"); 2921 return false; 2922 } 2923 2924 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2925 byte_i_ref += 1; 2926 2927 log_debug(redefine, class, annotation)("type_parameter_target: type_parameter_index=%d", type_parameter_index); 2928 } break; 2929 2930 case 0x10: 2931 // kind: type in extends clause of class or interface declaration 2932 // or in implements clause of interface declaration 2933 // location: ClassFile 2934 2935 { 2936 // struct: 2937 // supertype_target { 2938 // u2 supertype_index; 2939 // } 2940 // 2941 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2942 log_debug(redefine, class, annotation)("length() is too small for a supertype_target"); 2943 return false; 2944 } 2945 2946 u2 supertype_index = Bytes::get_Java_u2((address) 2947 type_annotations_typeArray->adr_at(byte_i_ref)); 2948 byte_i_ref += 2; 2949 2950 log_debug(redefine, class, annotation)("supertype_target: supertype_index=%d", supertype_index); 2951 } break; 2952 2953 case 0x11: 2954 // kind: type in bound of type parameter declaration of generic class or interface 2955 // location: ClassFile 2956 case 0x12: 2957 // kind: type in bound of type parameter declaration of generic method or constructor 2958 // location: method_info 2959 2960 { 2961 // struct: 2962 // type_parameter_bound_target { 2963 // u1 type_parameter_index; 2964 // u1 bound_index; 2965 // } 2966 // 2967 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2968 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_bound_target"); 2969 return false; 2970 } 2971 2972 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2973 byte_i_ref += 1; 2974 u1 bound_index = type_annotations_typeArray->at(byte_i_ref); 2975 byte_i_ref += 1; 2976 2977 log_debug(redefine, class, annotation) 2978 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d", type_parameter_index, bound_index); 2979 } break; 2980 2981 case 0x13: 2982 // kind: type in field declaration 2983 // location: field_info 2984 case 0x14: 2985 // kind: return type of method, or type of newly constructed object 2986 // location: method_info 2987 case 0x15: 2988 // kind: receiver type of method or constructor 2989 // location: method_info 2990 2991 { 2992 // struct: 2993 // empty_target { 2994 // } 2995 // 2996 log_debug(redefine, class, annotation)("empty_target"); 2997 } break; 2998 2999 case 0x16: 3000 // kind: type in formal parameter declaration of method, constructor, or lambda expression 3001 // location: method_info 3002 3003 { 3004 // struct: 3005 // formal_parameter_target { 3006 // u1 formal_parameter_index; 3007 // } 3008 // 3009 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 3010 log_debug(redefine, class, annotation)("length() is too small for a formal_parameter_target"); 3011 return false; 3012 } 3013 3014 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref); 3015 byte_i_ref += 1; 3016 3017 log_debug(redefine, class, annotation) 3018 ("formal_parameter_target: formal_parameter_index=%d", formal_parameter_index); 3019 } break; 3020 3021 case 0x17: 3022 // kind: type in throws clause of method or constructor 3023 // location: method_info 3024 3025 { 3026 // struct: 3027 // throws_target { 3028 // u2 throws_type_index 3029 // } 3030 // 3031 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 3032 log_debug(redefine, class, annotation)("length() is too small for a throws_target"); 3033 return false; 3034 } 3035 3036 u2 throws_type_index = Bytes::get_Java_u2((address) 3037 type_annotations_typeArray->adr_at(byte_i_ref)); 3038 byte_i_ref += 2; 3039 3040 log_debug(redefine, class, annotation)("throws_target: throws_type_index=%d", throws_type_index); 3041 } break; 3042 3043 case 0x40: 3044 // kind: type in local variable declaration 3045 // location: Code 3046 case 0x41: 3047 // kind: type in resource variable declaration 3048 // location: Code 3049 3050 { 3051 // struct: 3052 // localvar_target { 3053 // u2 table_length; 3054 // struct { 3055 // u2 start_pc; 3056 // u2 length; 3057 // u2 index; 3058 // } table[table_length]; 3059 // } 3060 // 3061 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 3062 // not enough room for a table_length let alone the rest of a localvar_target 3063 log_debug(redefine, class, annotation)("length() is too small for a localvar_target table_length"); 3064 return false; 3065 } 3066 3067 u2 table_length = Bytes::get_Java_u2((address) 3068 type_annotations_typeArray->adr_at(byte_i_ref)); 3069 byte_i_ref += 2; 3070 3071 log_debug(redefine, class, annotation)("localvar_target: table_length=%d", table_length); 3072 3073 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry 3074 int table_size = table_length * table_struct_size; 3075 3076 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) { 3077 // not enough room for a table 3078 log_debug(redefine, class, annotation)("length() is too small for a table array of length %d", table_length); 3079 return false; 3080 } 3081 3082 // Skip over table 3083 byte_i_ref += table_size; 3084 } break; 3085 3086 case 0x42: 3087 // kind: type in exception parameter declaration 3088 // location: Code 3089 3090 { 3091 // struct: 3092 // catch_target { 3093 // u2 exception_table_index; 3094 // } 3095 // 3096 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 3097 log_debug(redefine, class, annotation)("length() is too small for a catch_target"); 3098 return false; 3099 } 3100 3101 u2 exception_table_index = Bytes::get_Java_u2((address) 3102 type_annotations_typeArray->adr_at(byte_i_ref)); 3103 byte_i_ref += 2; 3104 3105 log_debug(redefine, class, annotation)("catch_target: exception_table_index=%d", exception_table_index); 3106 } break; 3107 3108 case 0x43: 3109 // kind: type in instanceof expression 3110 // location: Code 3111 case 0x44: 3112 // kind: type in new expression 3113 // location: Code 3114 case 0x45: 3115 // kind: type in method reference expression using ::new 3116 // location: Code 3117 case 0x46: 3118 // kind: type in method reference expression using ::Identifier 3119 // location: Code 3120 3121 { 3122 // struct: 3123 // offset_target { 3124 // u2 offset; 3125 // } 3126 // 3127 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 3128 log_debug(redefine, class, annotation)("length() is too small for a offset_target"); 3129 return false; 3130 } 3131 3132 u2 offset = Bytes::get_Java_u2((address) 3133 type_annotations_typeArray->adr_at(byte_i_ref)); 3134 byte_i_ref += 2; 3135 3136 log_debug(redefine, class, annotation)("offset_target: offset=%d", offset); 3137 } break; 3138 3139 case 0x47: 3140 // kind: type in cast expression 3141 // location: Code 3142 case 0x48: 3143 // kind: type argument for generic constructor in new expression or 3144 // explicit constructor invocation statement 3145 // location: Code 3146 case 0x49: 3147 // kind: type argument for generic method in method invocation expression 3148 // location: Code 3149 case 0x4A: 3150 // kind: type argument for generic constructor in method reference expression using ::new 3151 // location: Code 3152 case 0x4B: 3153 // kind: type argument for generic method in method reference expression using ::Identifier 3154 // location: Code 3155 3156 { 3157 // struct: 3158 // type_argument_target { 3159 // u2 offset; 3160 // u1 type_argument_index; 3161 // } 3162 // 3163 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) { 3164 log_debug(redefine, class, annotation)("length() is too small for a type_argument_target"); 3165 return false; 3166 } 3167 3168 u2 offset = Bytes::get_Java_u2((address) 3169 type_annotations_typeArray->adr_at(byte_i_ref)); 3170 byte_i_ref += 2; 3171 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref); 3172 byte_i_ref += 1; 3173 3174 log_debug(redefine, class, annotation) 3175 ("type_argument_target: offset=%d, type_argument_index=%d", offset, type_argument_index); 3176 } break; 3177 3178 default: 3179 log_debug(redefine, class, annotation)("unknown target_type"); 3180 #ifdef ASSERT 3181 ShouldNotReachHere(); 3182 #endif 3183 return false; 3184 } 3185 3186 return true; 3187 } // end skip_type_annotation_target() 3188 3189 3190 // Read, verify and skip over the type_path part so that rewriting 3191 // can continue in the later parts of the struct. 3192 // 3193 // type_path { 3194 // u1 path_length; 3195 // { 3196 // u1 type_path_kind; 3197 // u1 type_argument_index; 3198 // } path[path_length]; 3199 // } 3200 // 3201 bool VM_RedefineClasses::skip_type_annotation_type_path( 3202 AnnotationArray* type_annotations_typeArray, int &byte_i_ref) { 3203 3204 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 3205 // not enough room for a path_length let alone the rest of the type_path 3206 log_debug(redefine, class, annotation)("length() is too small for a type_path"); 3207 return false; 3208 } 3209 3210 u1 path_length = type_annotations_typeArray->at(byte_i_ref); 3211 byte_i_ref += 1; 3212 3213 log_debug(redefine, class, annotation)("type_path: path_length=%d", path_length); 3214 3215 int calc_path_length = 0; 3216 for (; calc_path_length < path_length; calc_path_length++) { 3217 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) { 3218 // not enough room for a path 3219 log_debug(redefine, class, annotation) 3220 ("length() is too small for path entry %d of %d", calc_path_length, path_length); 3221 return false; 3222 } 3223 3224 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref); 3225 byte_i_ref += 1; 3226 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref); 3227 byte_i_ref += 1; 3228 3229 log_debug(redefine, class, annotation) 3230 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d", 3231 calc_path_length, type_path_kind, type_argument_index); 3232 3233 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) { 3234 // not enough room for a path 3235 log_debug(redefine, class, annotation)("inconsistent type_path values"); 3236 return false; 3237 } 3238 } 3239 assert(path_length == calc_path_length, "sanity check"); 3240 3241 return true; 3242 } // end skip_type_annotation_type_path() 3243 3244 3245 // Rewrite constant pool references in the method's stackmap table. 3246 // These "structures" are adapted from the StackMapTable_attribute that 3247 // is described in section 4.8.4 of the 6.0 version of the VM spec 3248 // (dated 2005.10.26): 3249 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf 3250 // 3251 // stack_map { 3252 // u2 number_of_entries; 3253 // stack_map_frame entries[number_of_entries]; 3254 // } 3255 // 3256 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table( 3257 const methodHandle& method) { 3258 3259 if (!method->has_stackmap_table()) { 3260 return; 3261 } 3262 3263 AnnotationArray* stackmap_data = method->stackmap_data(); 3264 address stackmap_p = (address)stackmap_data->adr_at(0); 3265 address stackmap_end = stackmap_p + stackmap_data->length(); 3266 3267 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries"); 3268 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p); 3269 stackmap_p += 2; 3270 3271 log_debug(redefine, class, stackmap)("number_of_entries=%u", number_of_entries); 3272 3273 // walk through each stack_map_frame 3274 u2 calc_number_of_entries = 0; 3275 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) { 3276 // The stack_map_frame structure is a u1 frame_type followed by 3277 // 0 or more bytes of data: 3278 // 3279 // union stack_map_frame { 3280 // same_frame; 3281 // same_locals_1_stack_item_frame; 3282 // same_locals_1_stack_item_frame_extended; 3283 // chop_frame; 3284 // same_frame_extended; 3285 // append_frame; 3286 // full_frame; 3287 // } 3288 3289 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type"); 3290 u1 frame_type = *stackmap_p; 3291 stackmap_p++; 3292 3293 if (frame_type == 246) { // EARLY_LARVAL 3294 // rewrite_cp_refs in unset fields and fall through. 3295 rewrite_cp_refs_in_early_larval_stackmaps(stackmap_p, stackmap_end, calc_number_of_entries, frame_type); 3296 // The larval frames point to the next frame, so advance to the next frame and fall through. 3297 frame_type = *stackmap_p; 3298 stackmap_p++; 3299 } 3300 3301 // same_frame { 3302 // u1 frame_type = SAME; /* 0-63 */ 3303 // } 3304 if (frame_type <= 63) { 3305 // nothing more to do for same_frame 3306 } 3307 3308 // same_locals_1_stack_item_frame { 3309 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */ 3310 // verification_type_info stack[1]; 3311 // } 3312 else if (frame_type >= 64 && frame_type <= 127) { 3313 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3314 calc_number_of_entries, frame_type); 3315 } 3316 3317 // reserved for future use 3318 else if (frame_type >= 128 && frame_type <= 245) { 3319 // nothing more to do for reserved frame_types 3320 } 3321 3322 // same_locals_1_stack_item_frame_extended { 3323 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */ 3324 // u2 offset_delta; 3325 // verification_type_info stack[1]; 3326 // } 3327 else if (frame_type == 247) { 3328 stackmap_p += 2; 3329 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3330 calc_number_of_entries, frame_type); 3331 } 3332 3333 // chop_frame { 3334 // u1 frame_type = CHOP; /* 248-250 */ 3335 // u2 offset_delta; 3336 // } 3337 else if (frame_type >= 248 && frame_type <= 250) { 3338 stackmap_p += 2; 3339 } 3340 3341 // same_frame_extended { 3342 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/ 3343 // u2 offset_delta; 3344 // } 3345 else if (frame_type == 251) { 3346 stackmap_p += 2; 3347 } 3348 3349 // append_frame { 3350 // u1 frame_type = APPEND; /* 252-254 */ 3351 // u2 offset_delta; 3352 // verification_type_info locals[frame_type - 251]; 3353 // } 3354 else if (frame_type >= 252 && frame_type <= 254) { 3355 assert(stackmap_p + 2 <= stackmap_end, 3356 "no room for offset_delta"); 3357 stackmap_p += 2; 3358 u1 len = frame_type - 251; 3359 for (u1 i = 0; i < len; i++) { 3360 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3361 calc_number_of_entries, frame_type); 3362 } 3363 } 3364 3365 // full_frame { 3366 // u1 frame_type = FULL_FRAME; /* 255 */ 3367 // u2 offset_delta; 3368 // u2 number_of_locals; 3369 // verification_type_info locals[number_of_locals]; 3370 // u2 number_of_stack_items; 3371 // verification_type_info stack[number_of_stack_items]; 3372 // } 3373 else if (frame_type == 255) { 3374 assert(stackmap_p + 2 + 2 <= stackmap_end, 3375 "no room for smallest full_frame"); 3376 stackmap_p += 2; 3377 3378 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p); 3379 stackmap_p += 2; 3380 3381 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) { 3382 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3383 calc_number_of_entries, frame_type); 3384 } 3385 3386 // Use the largest size for the number_of_stack_items, but only get 3387 // the right number of bytes. 3388 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p); 3389 stackmap_p += 2; 3390 3391 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) { 3392 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3393 calc_number_of_entries, frame_type); 3394 } 3395 } 3396 } // end while there is a stack_map_frame 3397 assert(number_of_entries == calc_number_of_entries, "sanity check"); 3398 } // end rewrite_cp_refs_in_stack_map_table() 3399 3400 3401 // Rewrite constant pool references in the verification type info 3402 // portion of the method's stackmap table. These "structures" are 3403 // adapted from the StackMapTable_attribute that is described in 3404 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26): 3405 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf 3406 // 3407 // The verification_type_info structure is a u1 tag followed by 0 or 3408 // more bytes of data: 3409 // 3410 // union verification_type_info { 3411 // Top_variable_info; 3412 // Integer_variable_info; 3413 // Float_variable_info; 3414 // Long_variable_info; 3415 // Double_variable_info; 3416 // Null_variable_info; 3417 // UninitializedThis_variable_info; 3418 // Object_variable_info; 3419 // Uninitialized_variable_info; 3420 // } 3421 // 3422 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info( 3423 address& stackmap_p_ref, address stackmap_end, u2 frame_i, 3424 u1 frame_type) { 3425 3426 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag"); 3427 u1 tag = *stackmap_p_ref; 3428 stackmap_p_ref++; 3429 3430 switch (tag) { 3431 // Top_variable_info { 3432 // u1 tag = ITEM_Top; /* 0 */ 3433 // } 3434 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top 3435 case 0: // fall through 3436 3437 // Integer_variable_info { 3438 // u1 tag = ITEM_Integer; /* 1 */ 3439 // } 3440 case ITEM_Integer: // fall through 3441 3442 // Float_variable_info { 3443 // u1 tag = ITEM_Float; /* 2 */ 3444 // } 3445 case ITEM_Float: // fall through 3446 3447 // Double_variable_info { 3448 // u1 tag = ITEM_Double; /* 3 */ 3449 // } 3450 case ITEM_Double: // fall through 3451 3452 // Long_variable_info { 3453 // u1 tag = ITEM_Long; /* 4 */ 3454 // } 3455 case ITEM_Long: // fall through 3456 3457 // Null_variable_info { 3458 // u1 tag = ITEM_Null; /* 5 */ 3459 // } 3460 case ITEM_Null: // fall through 3461 3462 // UninitializedThis_variable_info { 3463 // u1 tag = ITEM_UninitializedThis; /* 6 */ 3464 // } 3465 case ITEM_UninitializedThis: 3466 // nothing more to do for the above tag types 3467 break; 3468 3469 // Object_variable_info { 3470 // u1 tag = ITEM_Object; /* 7 */ 3471 // u2 cpool_index; 3472 // } 3473 case ITEM_Object: 3474 { 3475 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index"); 3476 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref); 3477 u2 new_cp_index = find_new_index(cpool_index); 3478 if (new_cp_index != 0) { 3479 log_debug(redefine, class, stackmap)("mapped old cpool_index=%d", cpool_index); 3480 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index); 3481 cpool_index = new_cp_index; 3482 } 3483 stackmap_p_ref += 2; 3484 3485 log_debug(redefine, class, stackmap) 3486 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i, frame_type, cpool_index); 3487 } break; 3488 3489 // Uninitialized_variable_info { 3490 // u1 tag = ITEM_Uninitialized; /* 8 */ 3491 // u2 offset; 3492 // } 3493 case ITEM_Uninitialized: 3494 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset"); 3495 stackmap_p_ref += 2; 3496 break; 3497 3498 default: 3499 log_debug(redefine, class, stackmap)("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag); 3500 ShouldNotReachHere(); 3501 break; 3502 } // end switch (tag) 3503 } // end rewrite_cp_refs_in_verification_type_info() 3504 3505 3506 void VM_RedefineClasses::rewrite_cp_refs_in_early_larval_stackmaps( 3507 address& stackmap_p_ref, address stackmap_end, u2 frame_i, 3508 u1 frame_type) { 3509 3510 u2 num_early_larval_stackmaps = Bytes::get_Java_u2(stackmap_p_ref); 3511 stackmap_p_ref += 2; 3512 3513 for (u2 i = 0; i < num_early_larval_stackmaps; i++) { 3514 3515 u2 name_and_ref_index = Bytes::get_Java_u2(stackmap_p_ref); 3516 u2 new_cp_index = find_new_index(name_and_ref_index); 3517 if (new_cp_index != 0) { 3518 log_debug(redefine, class, stackmap)("mapped old name_and_ref_index=%d", name_and_ref_index); 3519 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index); 3520 name_and_ref_index = new_cp_index; 3521 } 3522 log_debug(redefine, class, stackmap) 3523 ("frame_i=%u, frame_type=%u, name_and_ref_index=%d", frame_i, frame_type, name_and_ref_index); 3524 3525 stackmap_p_ref += 2; 3526 } 3527 } // rewrite_cp_refs_in_early_larval_stackmaps 3528 3529 // Change the constant pool associated with klass scratch_class to scratch_cp. 3530 // scratch_cp_length elements are copied from scratch_cp to a smaller constant pool 3531 // and the smaller constant pool is associated with scratch_class. 3532 void VM_RedefineClasses::set_new_constant_pool( 3533 ClassLoaderData* loader_data, 3534 InstanceKlass* scratch_class, constantPoolHandle scratch_cp, 3535 int scratch_cp_length, TRAPS) { 3536 assert(scratch_cp->length() >= scratch_cp_length, "sanity check"); 3537 3538 // scratch_cp is a merged constant pool and has enough space for a 3539 // worst case merge situation. We want to associate the minimum 3540 // sized constant pool with the klass to save space. 3541 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK); 3542 constantPoolHandle smaller_cp(THREAD, cp); 3543 3544 // preserve version() value in the smaller copy 3545 int version = scratch_cp->version(); 3546 assert(version != 0, "sanity check"); 3547 smaller_cp->set_version(version); 3548 3549 // attach klass to new constant pool 3550 // reference to the cp holder is needed for copy_operands() 3551 smaller_cp->set_pool_holder(scratch_class); 3552 3553 smaller_cp->copy_fields(scratch_cp()); 3554 3555 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD); 3556 if (HAS_PENDING_EXCEPTION) { 3557 // Exception is handled in the caller 3558 loader_data->add_to_deallocate_list(smaller_cp()); 3559 return; 3560 } 3561 scratch_cp = smaller_cp; 3562 3563 // attach new constant pool to klass 3564 scratch_class->set_constants(scratch_cp()); 3565 scratch_cp->initialize_unresolved_klasses(loader_data, CHECK); 3566 3567 int i; // for portability 3568 3569 // update each field in klass to use new constant pool indices as needed 3570 int java_fields; 3571 int injected_fields; 3572 bool update_required = false; 3573 GrowableArray<FieldInfo>* fields = FieldInfoStream::create_FieldInfoArray(scratch_class->fieldinfo_stream(), &java_fields, &injected_fields); 3574 for (int i = 0; i < java_fields; i++) { 3575 FieldInfo* fi = fields->adr_at(i); 3576 jshort cur_index = fi->name_index(); 3577 jshort new_index = find_new_index(cur_index); 3578 if (new_index != 0) { 3579 log_trace(redefine, class, constantpool)("field-name_index change: %d to %d", cur_index, new_index); 3580 fi->set_name_index(new_index); 3581 update_required = true; 3582 } 3583 cur_index = fi->signature_index(); 3584 new_index = find_new_index(cur_index); 3585 if (new_index != 0) { 3586 log_trace(redefine, class, constantpool)("field-signature_index change: %d to %d", cur_index, new_index); 3587 fi->set_signature_index(new_index); 3588 update_required = true; 3589 } 3590 cur_index = fi->initializer_index(); 3591 new_index = find_new_index(cur_index); 3592 if (new_index != 0) { 3593 log_trace(redefine, class, constantpool)("field-initval_index change: %d to %d", cur_index, new_index); 3594 fi->set_initializer_index(new_index); 3595 update_required = true; 3596 } 3597 cur_index = fi->generic_signature_index(); 3598 new_index = find_new_index(cur_index); 3599 if (new_index != 0) { 3600 log_trace(redefine, class, constantpool)("field-generic_signature change: %d to %d", cur_index, new_index); 3601 fi->set_generic_signature_index(new_index); 3602 update_required = true; 3603 } 3604 } 3605 if (update_required) { 3606 Array<u1>* old_stream = scratch_class->fieldinfo_stream(); 3607 assert(fields->length() == (java_fields + injected_fields), "Must be"); 3608 Array<u1>* new_fis = FieldInfoStream::create_FieldInfoStream(fields, java_fields, injected_fields, scratch_class->class_loader_data(), CHECK); 3609 scratch_class->set_fieldinfo_stream(new_fis); 3610 MetadataFactory::free_array<u1>(scratch_class->class_loader_data(), old_stream); 3611 } 3612 3613 // Update constant pool indices in the inner classes info to use 3614 // new constant indices as needed. The inner classes info is a 3615 // quadruple: 3616 // (inner_class_info, outer_class_info, inner_name, inner_access_flags) 3617 InnerClassesIterator iter(scratch_class); 3618 for (; !iter.done(); iter.next()) { 3619 int cur_index = iter.inner_class_info_index(); 3620 if (cur_index == 0) { 3621 continue; // JVM spec. allows null inner class refs so skip it 3622 } 3623 u2 new_index = find_new_index(cur_index); 3624 if (new_index != 0) { 3625 log_trace(redefine, class, constantpool)("inner_class_info change: %d to %d", cur_index, new_index); 3626 iter.set_inner_class_info_index(new_index); 3627 } 3628 cur_index = iter.outer_class_info_index(); 3629 new_index = find_new_index(cur_index); 3630 if (new_index != 0) { 3631 log_trace(redefine, class, constantpool)("outer_class_info change: %d to %d", cur_index, new_index); 3632 iter.set_outer_class_info_index(new_index); 3633 } 3634 cur_index = iter.inner_name_index(); 3635 new_index = find_new_index(cur_index); 3636 if (new_index != 0) { 3637 log_trace(redefine, class, constantpool)("inner_name change: %d to %d", cur_index, new_index); 3638 iter.set_inner_name_index(new_index); 3639 } 3640 } // end for each inner class 3641 3642 // Attach each method in klass to the new constant pool and update 3643 // to use new constant pool indices as needed: 3644 Array<Method*>* methods = scratch_class->methods(); 3645 for (i = methods->length() - 1; i >= 0; i--) { 3646 methodHandle method(THREAD, methods->at(i)); 3647 method->set_constants(scratch_cp()); 3648 3649 u2 new_index = find_new_index(method->name_index()); 3650 if (new_index != 0) { 3651 log_trace(redefine, class, constantpool) 3652 ("method-name_index change: %d to %d", method->name_index(), new_index); 3653 method->set_name_index(new_index); 3654 } 3655 new_index = find_new_index(method->signature_index()); 3656 if (new_index != 0) { 3657 log_trace(redefine, class, constantpool) 3658 ("method-signature_index change: %d to %d", method->signature_index(), new_index); 3659 method->set_signature_index(new_index); 3660 } 3661 new_index = find_new_index(method->generic_signature_index()); 3662 if (new_index != 0) { 3663 log_trace(redefine, class, constantpool) 3664 ("method-generic_signature_index change: %d to %d", method->generic_signature_index(), new_index); 3665 method->constMethod()->set_generic_signature_index(new_index); 3666 } 3667 3668 // Update constant pool indices in the method's checked exception 3669 // table to use new constant indices as needed. 3670 int cext_length = method->checked_exceptions_length(); 3671 if (cext_length > 0) { 3672 CheckedExceptionElement * cext_table = 3673 method->checked_exceptions_start(); 3674 for (int j = 0; j < cext_length; j++) { 3675 int cur_index = cext_table[j].class_cp_index; 3676 int new_index = find_new_index(cur_index); 3677 if (new_index != 0) { 3678 log_trace(redefine, class, constantpool)("cext-class_cp_index change: %d to %d", cur_index, new_index); 3679 cext_table[j].class_cp_index = (u2)new_index; 3680 } 3681 } // end for each checked exception table entry 3682 } // end if there are checked exception table entries 3683 3684 // Update each catch type index in the method's exception table 3685 // to use new constant pool indices as needed. The exception table 3686 // holds quadruple entries of the form: 3687 // (beg_bci, end_bci, handler_bci, klass_index) 3688 3689 ExceptionTable ex_table(method()); 3690 int ext_length = ex_table.length(); 3691 3692 for (int j = 0; j < ext_length; j ++) { 3693 int cur_index = ex_table.catch_type_index(j); 3694 u2 new_index = find_new_index(cur_index); 3695 if (new_index != 0) { 3696 log_trace(redefine, class, constantpool)("ext-klass_index change: %d to %d", cur_index, new_index); 3697 ex_table.set_catch_type_index(j, new_index); 3698 } 3699 } // end for each exception table entry 3700 3701 // Update constant pool indices in the method's local variable 3702 // table to use new constant indices as needed. The local variable 3703 // table hold sextuple entries of the form: 3704 // (start_pc, length, name_index, descriptor_index, signature_index, slot) 3705 int lvt_length = method->localvariable_table_length(); 3706 if (lvt_length > 0) { 3707 LocalVariableTableElement * lv_table = 3708 method->localvariable_table_start(); 3709 for (int j = 0; j < lvt_length; j++) { 3710 int cur_index = lv_table[j].name_cp_index; 3711 int new_index = find_new_index(cur_index); 3712 if (new_index != 0) { 3713 log_trace(redefine, class, constantpool)("lvt-name_cp_index change: %d to %d", cur_index, new_index); 3714 lv_table[j].name_cp_index = (u2)new_index; 3715 } 3716 cur_index = lv_table[j].descriptor_cp_index; 3717 new_index = find_new_index(cur_index); 3718 if (new_index != 0) { 3719 log_trace(redefine, class, constantpool)("lvt-descriptor_cp_index change: %d to %d", cur_index, new_index); 3720 lv_table[j].descriptor_cp_index = (u2)new_index; 3721 } 3722 cur_index = lv_table[j].signature_cp_index; 3723 new_index = find_new_index(cur_index); 3724 if (new_index != 0) { 3725 log_trace(redefine, class, constantpool)("lvt-signature_cp_index change: %d to %d", cur_index, new_index); 3726 lv_table[j].signature_cp_index = (u2)new_index; 3727 } 3728 } // end for each local variable table entry 3729 } // end if there are local variable table entries 3730 3731 // Update constant pool indices in the method's method_parameters. 3732 int mp_length = method->method_parameters_length(); 3733 if (mp_length > 0) { 3734 MethodParametersElement* elem = method->method_parameters_start(); 3735 for (int j = 0; j < mp_length; j++) { 3736 const int cp_index = elem[j].name_cp_index; 3737 const int new_cp_index = find_new_index(cp_index); 3738 if (new_cp_index != 0) { 3739 elem[j].name_cp_index = (u2)new_cp_index; 3740 } 3741 } 3742 } 3743 3744 rewrite_cp_refs_in_stack_map_table(method); 3745 } // end for each method 3746 } // end set_new_constant_pool() 3747 3748 3749 // Unevolving classes may point to methods of the_class directly 3750 // from their constant pool caches, itables, and/or vtables. We 3751 // use the ClassLoaderDataGraph::classes_do() facility and this helper 3752 // to fix up these pointers. MethodData also points to old methods and 3753 // must be cleaned. 3754 3755 // Adjust cpools and vtables closure 3756 void VM_RedefineClasses::AdjustAndCleanMetadata::do_klass(Klass* k) { 3757 3758 // This is a very busy routine. We don't want too much tracing 3759 // printed out. 3760 bool trace_name_printed = false; 3761 3762 // If the class being redefined is java.lang.Object, we need to fix all 3763 // array class vtables also. The _has_redefined_Object flag is global. 3764 // Once the java.lang.Object has been redefined (by the current or one 3765 // of the previous VM_RedefineClasses operations) we have to always 3766 // adjust method entries for array classes. 3767 if (k->is_array_klass() && _has_redefined_Object) { 3768 k->vtable().adjust_method_entries(&trace_name_printed); 3769 3770 } else if (k->is_instance_klass()) { 3771 HandleMark hm(_thread); 3772 InstanceKlass *ik = InstanceKlass::cast(k); 3773 3774 // Clean MethodData of this class's methods so they don't refer to 3775 // old methods that are no longer running. 3776 Array<Method*>* methods = ik->methods(); 3777 int num_methods = methods->length(); 3778 for (int index = 0; index < num_methods; ++index) { 3779 if (methods->at(index)->method_data() != nullptr) { 3780 methods->at(index)->method_data()->clean_weak_method_links(); 3781 } 3782 } 3783 3784 // Adjust all vtables, default methods and itables, to clean out old methods. 3785 ResourceMark rm(_thread); 3786 if (ik->vtable_length() > 0) { 3787 ik->vtable().adjust_method_entries(&trace_name_printed); 3788 ik->adjust_default_methods(&trace_name_printed); 3789 } 3790 3791 if (ik->itable_length() > 0) { 3792 ik->itable().adjust_method_entries(&trace_name_printed); 3793 } 3794 3795 // The constant pools in other classes (other_cp) can refer to 3796 // old methods. We have to update method information in 3797 // other_cp's cache. If other_cp has a previous version, then we 3798 // have to repeat the process for each previous version. The 3799 // constant pool cache holds the Method*s for non-virtual 3800 // methods and for virtual, final methods. 3801 // 3802 // Special case: if the current class is being redefined by the current 3803 // VM_RedefineClasses operation, then new_cp has already been attached 3804 // to the_class and old_cp has already been added as a previous version. 3805 // The new_cp doesn't have any cached references to old methods so it 3806 // doesn't need to be updated and we could optimize by skipping it. 3807 // However, the current class can be marked as being redefined by another 3808 // VM_RedefineClasses operation which has already executed its doit_prologue 3809 // and needs cpcache method entries adjusted. For simplicity, the cpcache 3810 // update is done unconditionally. It should result in doing nothing for 3811 // classes being redefined by the current VM_RedefineClasses operation. 3812 // Method entries in the previous version(s) are adjusted as well. 3813 ConstantPoolCache* cp_cache; 3814 3815 // this klass' constant pool cache may need adjustment 3816 ConstantPool* other_cp = ik->constants(); 3817 cp_cache = other_cp->cache(); 3818 if (cp_cache != nullptr) { 3819 cp_cache->adjust_method_entries(&trace_name_printed); 3820 } 3821 3822 // the previous versions' constant pool caches may need adjustment 3823 for (InstanceKlass* pv_node = ik->previous_versions(); 3824 pv_node != nullptr; 3825 pv_node = pv_node->previous_versions()) { 3826 cp_cache = pv_node->constants()->cache(); 3827 if (cp_cache != nullptr) { 3828 cp_cache->adjust_method_entries(&trace_name_printed); 3829 } 3830 } 3831 } 3832 } 3833 3834 void VM_RedefineClasses::update_jmethod_ids() { 3835 for (int j = 0; j < _matching_methods_length; ++j) { 3836 Method* old_method = _matching_old_methods[j]; 3837 jmethodID jmid = old_method->find_jmethod_id_or_null(); 3838 if (jmid != nullptr) { 3839 // There is a jmethodID, change it to point to the new method 3840 Method* new_method = _matching_new_methods[j]; 3841 Method::change_method_associated_with_jmethod_id(jmid, new_method); 3842 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j], 3843 "should be replaced"); 3844 } 3845 } 3846 } 3847 3848 int VM_RedefineClasses::check_methods_and_mark_as_obsolete() { 3849 int emcp_method_count = 0; 3850 int obsolete_count = 0; 3851 int old_index = 0; 3852 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) { 3853 Method* old_method = _matching_old_methods[j]; 3854 Method* new_method = _matching_new_methods[j]; 3855 Method* old_array_method; 3856 3857 // Maintain an old_index into the _old_methods array by skipping 3858 // deleted methods 3859 while ((old_array_method = _old_methods->at(old_index)) != old_method) { 3860 ++old_index; 3861 } 3862 3863 if (MethodComparator::methods_EMCP(old_method, new_method)) { 3864 // The EMCP definition from JSR-163 requires the bytecodes to be 3865 // the same with the exception of constant pool indices which may 3866 // differ. However, the constants referred to by those indices 3867 // must be the same. 3868 // 3869 // We use methods_EMCP() for comparison since constant pool 3870 // merging can remove duplicate constant pool entries that were 3871 // present in the old method and removed from the rewritten new 3872 // method. A faster binary comparison function would consider the 3873 // old and new methods to be different when they are actually 3874 // EMCP. 3875 // 3876 // The old and new methods are EMCP and you would think that we 3877 // could get rid of one of them here and now and save some space. 3878 // However, the concept of EMCP only considers the bytecodes and 3879 // the constant pool entries in the comparison. Other things, 3880 // e.g., the line number table (LNT) or the local variable table 3881 // (LVT) don't count in the comparison. So the new (and EMCP) 3882 // method can have a new LNT that we need so we can't just 3883 // overwrite the new method with the old method. 3884 // 3885 // When this routine is called, we have already attached the new 3886 // methods to the_class so the old methods are effectively 3887 // overwritten. However, if an old method is still executing, 3888 // then the old method cannot be collected until sometime after 3889 // the old method call has returned. So the overwriting of old 3890 // methods by new methods will save us space except for those 3891 // (hopefully few) old methods that are still executing. 3892 // 3893 // A method refers to a ConstMethod* and this presents another 3894 // possible avenue to space savings. The ConstMethod* in the 3895 // new method contains possibly new attributes (LNT, LVT, etc). 3896 // At first glance, it seems possible to save space by replacing 3897 // the ConstMethod* in the old method with the ConstMethod* 3898 // from the new method. The old and new methods would share the 3899 // same ConstMethod* and we would save the space occupied by 3900 // the old ConstMethod*. However, the ConstMethod* contains 3901 // a back reference to the containing method. Sharing the 3902 // ConstMethod* between two methods could lead to confusion in 3903 // the code that uses the back reference. This would lead to 3904 // brittle code that could be broken in non-obvious ways now or 3905 // in the future. 3906 // 3907 // Another possibility is to copy the ConstMethod* from the new 3908 // method to the old method and then overwrite the new method with 3909 // the old method. Since the ConstMethod* contains the bytecodes 3910 // for the method embedded in the oop, this option would change 3911 // the bytecodes out from under any threads executing the old 3912 // method and make the thread's bcp invalid. Since EMCP requires 3913 // that the bytecodes be the same modulo constant pool indices, it 3914 // is straight forward to compute the correct new bcp in the new 3915 // ConstMethod* from the old bcp in the old ConstMethod*. The 3916 // time consuming part would be searching all the frames in all 3917 // of the threads to find all of the calls to the old method. 3918 // 3919 // It looks like we will have to live with the limited savings 3920 // that we get from effectively overwriting the old methods 3921 // when the new methods are attached to the_class. 3922 3923 // Count number of methods that are EMCP. The method will be marked 3924 // old but not obsolete if it is EMCP. 3925 emcp_method_count++; 3926 3927 // An EMCP method is _not_ obsolete. An obsolete method has a 3928 // different jmethodID than the current method. An EMCP method 3929 // has the same jmethodID as the current method. Having the 3930 // same jmethodID for all EMCP versions of a method allows for 3931 // a consistent view of the EMCP methods regardless of which 3932 // EMCP method you happen to have in hand. For example, a 3933 // breakpoint set in one EMCP method will work for all EMCP 3934 // versions of the method including the current one. 3935 } else { 3936 // mark obsolete methods as such 3937 old_method->set_is_obsolete(); 3938 obsolete_count++; 3939 3940 // obsolete methods need a unique idnum so they become new entries in 3941 // the jmethodID cache in InstanceKlass 3942 assert(old_method->method_idnum() == new_method->method_idnum(), "must match"); 3943 u2 num = InstanceKlass::cast(_the_class)->next_method_idnum(); 3944 if (num != ConstMethod::UNSET_IDNUM) { 3945 old_method->set_method_idnum(num); 3946 } 3947 3948 // With tracing we try not to "yack" too much. The position of 3949 // this trace assumes there are fewer obsolete methods than 3950 // EMCP methods. 3951 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) { 3952 ResourceMark rm; 3953 log_trace(redefine, class, obsolete, mark) 3954 ("mark %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string()); 3955 } 3956 } 3957 old_method->set_is_old(); 3958 } 3959 for (int i = 0; i < _deleted_methods_length; ++i) { 3960 Method* old_method = _deleted_methods[i]; 3961 3962 assert(!old_method->has_vtable_index(), 3963 "cannot delete methods with vtable entries");; 3964 3965 // Mark all deleted methods as old, obsolete and deleted 3966 old_method->set_is_deleted(); 3967 old_method->set_is_old(); 3968 old_method->set_is_obsolete(); 3969 ++obsolete_count; 3970 // With tracing we try not to "yack" too much. The position of 3971 // this trace assumes there are fewer obsolete methods than 3972 // EMCP methods. 3973 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) { 3974 ResourceMark rm; 3975 log_trace(redefine, class, obsolete, mark) 3976 ("mark deleted %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string()); 3977 } 3978 } 3979 assert((emcp_method_count + obsolete_count) == _old_methods->length(), 3980 "sanity check"); 3981 log_trace(redefine, class, obsolete, mark)("EMCP_cnt=%d, obsolete_cnt=%d", emcp_method_count, obsolete_count); 3982 return emcp_method_count; 3983 } 3984 3985 // This internal class transfers the native function registration from old methods 3986 // to new methods. It is designed to handle both the simple case of unchanged 3987 // native methods and the complex cases of native method prefixes being added and/or 3988 // removed. 3989 // It expects only to be used during the VM_RedefineClasses op (a safepoint). 3990 // 3991 // This class is used after the new methods have been installed in "the_class". 3992 // 3993 // So, for example, the following must be handled. Where 'm' is a method and 3994 // a number followed by an underscore is a prefix. 3995 // 3996 // Old Name New Name 3997 // Simple transfer to new method m -> m 3998 // Add prefix m -> 1_m 3999 // Remove prefix 1_m -> m 4000 // Simultaneous add of prefixes m -> 3_2_1_m 4001 // Simultaneous removal of prefixes 3_2_1_m -> m 4002 // Simultaneous add and remove 1_m -> 2_m 4003 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m 4004 // 4005 class TransferNativeFunctionRegistration { 4006 private: 4007 InstanceKlass* the_class; 4008 int prefix_count; 4009 char** prefixes; 4010 4011 // Recursively search the binary tree of possibly prefixed method names. 4012 // Iteration could be used if all agents were well behaved. Full tree walk is 4013 // more resilent to agents not cleaning up intermediate methods. 4014 // Branch at each depth in the binary tree is: 4015 // (1) without the prefix. 4016 // (2) with the prefix. 4017 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...) 4018 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len, 4019 Symbol* signature) { 4020 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len); 4021 if (name_symbol != nullptr) { 4022 Method* method = the_class->lookup_method(name_symbol, signature); 4023 if (method != nullptr) { 4024 // Even if prefixed, intermediate methods must exist. 4025 if (method->is_native()) { 4026 // Wahoo, we found a (possibly prefixed) version of the method, return it. 4027 return method; 4028 } 4029 if (depth < prefix_count) { 4030 // Try applying further prefixes (other than this one). 4031 method = search_prefix_name_space(depth+1, name_str, name_len, signature); 4032 if (method != nullptr) { 4033 return method; // found 4034 } 4035 4036 // Try adding this prefix to the method name and see if it matches 4037 // another method name. 4038 char* prefix = prefixes[depth]; 4039 size_t prefix_len = strlen(prefix); 4040 size_t trial_len = name_len + prefix_len; 4041 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1); 4042 strcpy(trial_name_str, prefix); 4043 strcat(trial_name_str, name_str); 4044 method = search_prefix_name_space(depth+1, trial_name_str, trial_len, 4045 signature); 4046 if (method != nullptr) { 4047 // If found along this branch, it was prefixed, mark as such 4048 method->set_is_prefixed_native(); 4049 return method; // found 4050 } 4051 } 4052 } 4053 } 4054 return nullptr; // This whole branch bore nothing 4055 } 4056 4057 // Return the method name with old prefixes stripped away. 4058 char* method_name_without_prefixes(Method* method) { 4059 Symbol* name = method->name(); 4060 char* name_str = name->as_utf8(); 4061 4062 // Old prefixing may be defunct, strip prefixes, if any. 4063 for (int i = prefix_count-1; i >= 0; i--) { 4064 char* prefix = prefixes[i]; 4065 size_t prefix_len = strlen(prefix); 4066 if (strncmp(prefix, name_str, prefix_len) == 0) { 4067 name_str += prefix_len; 4068 } 4069 } 4070 return name_str; 4071 } 4072 4073 // Strip any prefixes off the old native method, then try to find a 4074 // (possibly prefixed) new native that matches it. 4075 Method* strip_and_search_for_new_native(Method* method) { 4076 ResourceMark rm; 4077 char* name_str = method_name_without_prefixes(method); 4078 return search_prefix_name_space(0, name_str, strlen(name_str), 4079 method->signature()); 4080 } 4081 4082 public: 4083 4084 // Construct a native method transfer processor for this class. 4085 TransferNativeFunctionRegistration(InstanceKlass* _the_class) { 4086 assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); 4087 4088 the_class = _the_class; 4089 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count); 4090 } 4091 4092 // Attempt to transfer any of the old or deleted methods that are native 4093 void transfer_registrations(Method** old_methods, int methods_length) { 4094 for (int j = 0; j < methods_length; j++) { 4095 Method* old_method = old_methods[j]; 4096 4097 if (old_method->is_native() && old_method->has_native_function()) { 4098 Method* new_method = strip_and_search_for_new_native(old_method); 4099 if (new_method != nullptr) { 4100 // Actually set the native function in the new method. 4101 // Redefine does not send events (except CFLH), certainly not this 4102 // behind the scenes re-registration. 4103 new_method->set_native_function(old_method->native_function(), 4104 !Method::native_bind_event_is_interesting); 4105 } 4106 } 4107 } 4108 } 4109 }; 4110 4111 // Don't lose the association between a native method and its JNI function. 4112 void VM_RedefineClasses::transfer_old_native_function_registrations(InstanceKlass* the_class) { 4113 TransferNativeFunctionRegistration transfer(the_class); 4114 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length); 4115 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length); 4116 } 4117 4118 // Deoptimize all compiled code that depends on the classes redefined. 4119 // 4120 // If the can_redefine_classes capability is obtained in the onload 4121 // phase or 'AlwaysRecordEvolDependencies' is true, then the compiler has 4122 // recorded all dependencies from startup. In that case we need only 4123 // deoptimize and throw away all compiled code that depends on the class. 4124 // 4125 // If can_redefine_classes is obtained sometime after the onload phase 4126 // (and 'AlwaysRecordEvolDependencies' is false) then the dependency 4127 // information may be incomplete. In that case the first call to 4128 // RedefineClasses causes all compiled code to be thrown away. As 4129 // can_redefine_classes has been obtained then all future compilations will 4130 // record dependencies so second and subsequent calls to RedefineClasses 4131 // need only throw away code that depends on the class. 4132 // 4133 4134 void VM_RedefineClasses::flush_dependent_code() { 4135 assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); 4136 assert(JvmtiExport::all_dependencies_are_recorded() || !AlwaysRecordEvolDependencies, "sanity check"); 4137 4138 DeoptimizationScope deopt_scope; 4139 4140 // This is the first redefinition, mark all the nmethods for deoptimization 4141 if (!JvmtiExport::all_dependencies_are_recorded()) { 4142 CodeCache::mark_all_nmethods_for_evol_deoptimization(&deopt_scope); 4143 log_debug(redefine, class, nmethod)("Marked all nmethods for deopt"); 4144 } else { 4145 CodeCache::mark_dependents_for_evol_deoptimization(&deopt_scope); 4146 log_debug(redefine, class, nmethod)("Marked dependent nmethods for deopt"); 4147 } 4148 4149 deopt_scope.deoptimize_marked(); 4150 4151 // From now on we know that the dependency information is complete 4152 JvmtiExport::set_all_dependencies_are_recorded(true); 4153 } 4154 4155 void VM_RedefineClasses::compute_added_deleted_matching_methods() { 4156 Method* old_method; 4157 Method* new_method; 4158 4159 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 4160 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 4161 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length()); 4162 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 4163 4164 _matching_methods_length = 0; 4165 _deleted_methods_length = 0; 4166 _added_methods_length = 0; 4167 4168 int nj = 0; 4169 int oj = 0; 4170 while (true) { 4171 if (oj >= _old_methods->length()) { 4172 if (nj >= _new_methods->length()) { 4173 break; // we've looked at everything, done 4174 } 4175 // New method at the end 4176 new_method = _new_methods->at(nj); 4177 _added_methods[_added_methods_length++] = new_method; 4178 ++nj; 4179 } else if (nj >= _new_methods->length()) { 4180 // Old method, at the end, is deleted 4181 old_method = _old_methods->at(oj); 4182 _deleted_methods[_deleted_methods_length++] = old_method; 4183 ++oj; 4184 } else { 4185 old_method = _old_methods->at(oj); 4186 new_method = _new_methods->at(nj); 4187 if (old_method->name() == new_method->name()) { 4188 if (old_method->signature() == new_method->signature()) { 4189 _matching_old_methods[_matching_methods_length ] = old_method; 4190 _matching_new_methods[_matching_methods_length++] = new_method; 4191 ++nj; 4192 ++oj; 4193 } else { 4194 // added overloaded have already been moved to the end, 4195 // so this is a deleted overloaded method 4196 _deleted_methods[_deleted_methods_length++] = old_method; 4197 ++oj; 4198 } 4199 } else { // names don't match 4200 if (old_method->name()->fast_compare(new_method->name()) > 0) { 4201 // new method 4202 _added_methods[_added_methods_length++] = new_method; 4203 ++nj; 4204 } else { 4205 // deleted method 4206 _deleted_methods[_deleted_methods_length++] = old_method; 4207 ++oj; 4208 } 4209 } 4210 } 4211 } 4212 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity"); 4213 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity"); 4214 } 4215 4216 4217 void VM_RedefineClasses::swap_annotations(InstanceKlass* the_class, 4218 InstanceKlass* scratch_class) { 4219 // Swap annotation fields values 4220 Annotations* old_annotations = the_class->annotations(); 4221 the_class->set_annotations(scratch_class->annotations()); 4222 scratch_class->set_annotations(old_annotations); 4223 } 4224 4225 4226 // Install the redefinition of a class: 4227 // - house keeping (flushing breakpoints and caches, deoptimizing 4228 // dependent compiled code) 4229 // - replacing parts in the_class with parts from scratch_class 4230 // - adding a weak reference to track the obsolete but interesting 4231 // parts of the_class 4232 // - adjusting constant pool caches and vtables in other classes 4233 // that refer to methods in the_class. These adjustments use the 4234 // ClassLoaderDataGraph::classes_do() facility which only allows 4235 // a helper method to be specified. The interesting parameters 4236 // that we would like to pass to the helper method are saved in 4237 // static global fields in the VM operation. 4238 void VM_RedefineClasses::redefine_single_class(Thread* current, jclass the_jclass, 4239 InstanceKlass* scratch_class) { 4240 4241 HandleMark hm(current); // make sure handles from this call are freed 4242 4243 if (log_is_enabled(Info, redefine, class, timer)) { 4244 _timer_rsc_phase1.start(); 4245 } 4246 4247 InstanceKlass* the_class = get_ik(the_jclass); 4248 4249 // Set a flag to control and optimize adjusting method entries 4250 _has_redefined_Object |= the_class == vmClasses::Object_klass(); 4251 4252 // Remove all breakpoints in methods of this class 4253 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints(); 4254 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class); 4255 4256 _old_methods = the_class->methods(); 4257 _new_methods = scratch_class->methods(); 4258 _the_class = the_class; 4259 compute_added_deleted_matching_methods(); 4260 update_jmethod_ids(); 4261 4262 _any_class_has_resolved_methods = the_class->has_resolved_methods() || _any_class_has_resolved_methods; 4263 4264 // Attach new constant pool to the original klass. The original 4265 // klass still refers to the old constant pool (for now). 4266 scratch_class->constants()->set_pool_holder(the_class); 4267 4268 #if 0 4269 // In theory, with constant pool merging in place we should be able 4270 // to save space by using the new, merged constant pool in place of 4271 // the old constant pool(s). By "pool(s)" I mean the constant pool in 4272 // the klass version we are replacing now and any constant pool(s) in 4273 // previous versions of klass. Nice theory, doesn't work in practice. 4274 // When this code is enabled, even simple programs throw NullPointer 4275 // exceptions. I'm guessing that this is caused by some constant pool 4276 // cache difference between the new, merged constant pool and the 4277 // constant pool that was just being used by the klass. I'm keeping 4278 // this code around to archive the idea, but the code has to remain 4279 // disabled for now. 4280 4281 // Attach each old method to the new constant pool. This can be 4282 // done here since we are past the bytecode verification and 4283 // constant pool optimization phases. 4284 for (int i = _old_methods->length() - 1; i >= 0; i--) { 4285 Method* method = _old_methods->at(i); 4286 method->set_constants(scratch_class->constants()); 4287 } 4288 4289 // NOTE: this doesn't work because you can redefine the same class in two 4290 // threads, each getting their own constant pool data appended to the 4291 // original constant pool. In order for the new methods to work when they 4292 // become old methods, they need to keep their updated copy of the constant pool. 4293 4294 { 4295 // walk all previous versions of the klass 4296 InstanceKlass *ik = the_class; 4297 PreviousVersionWalker pvw(ik); 4298 do { 4299 ik = pvw.next_previous_version(); 4300 if (ik != nullptr) { 4301 4302 // attach previous version of klass to the new constant pool 4303 ik->set_constants(scratch_class->constants()); 4304 4305 // Attach each method in the previous version of klass to the 4306 // new constant pool 4307 Array<Method*>* prev_methods = ik->methods(); 4308 for (int i = prev_methods->length() - 1; i >= 0; i--) { 4309 Method* method = prev_methods->at(i); 4310 method->set_constants(scratch_class->constants()); 4311 } 4312 } 4313 } while (ik != nullptr); 4314 } 4315 #endif 4316 4317 // Replace methods and constantpool 4318 the_class->set_methods(_new_methods); 4319 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods, 4320 // and to be able to undo operation easily. 4321 4322 Array<int>* old_ordering = the_class->method_ordering(); 4323 the_class->set_method_ordering(scratch_class->method_ordering()); 4324 scratch_class->set_method_ordering(old_ordering); 4325 4326 ConstantPool* old_constants = the_class->constants(); 4327 the_class->set_constants(scratch_class->constants()); 4328 scratch_class->set_constants(old_constants); // See the previous comment. 4329 #if 0 4330 // We are swapping the guts of "the new class" with the guts of "the 4331 // class". Since the old constant pool has just been attached to "the 4332 // new class", it seems logical to set the pool holder in the old 4333 // constant pool also. However, doing this will change the observable 4334 // class hierarchy for any old methods that are still executing. A 4335 // method can query the identity of its "holder" and this query uses 4336 // the method's constant pool link to find the holder. The change in 4337 // holding class from "the class" to "the new class" can confuse 4338 // things. 4339 // 4340 // Setting the old constant pool's holder will also cause 4341 // verification done during vtable initialization below to fail. 4342 // During vtable initialization, the vtable's class is verified to be 4343 // a subtype of the method's holder. The vtable's class is "the 4344 // class" and the method's holder is gotten from the constant pool 4345 // link in the method itself. For "the class"'s directly implemented 4346 // methods, the method holder is "the class" itself (as gotten from 4347 // the new constant pool). The check works fine in this case. The 4348 // check also works fine for methods inherited from super classes. 4349 // 4350 // Miranda methods are a little more complicated. A miranda method is 4351 // provided by an interface when the class implementing the interface 4352 // does not provide its own method. These interfaces are implemented 4353 // internally as an InstanceKlass. These special instanceKlasses 4354 // share the constant pool of the class that "implements" the 4355 // interface. By sharing the constant pool, the method holder of a 4356 // miranda method is the class that "implements" the interface. In a 4357 // non-redefine situation, the subtype check works fine. However, if 4358 // the old constant pool's pool holder is modified, then the check 4359 // fails because there is no class hierarchy relationship between the 4360 // vtable's class and "the new class". 4361 4362 old_constants->set_pool_holder(scratch_class()); 4363 #endif 4364 4365 // track number of methods that are EMCP for add_previous_version() call below 4366 int emcp_method_count = check_methods_and_mark_as_obsolete(); 4367 transfer_old_native_function_registrations(the_class); 4368 4369 if (scratch_class->get_cached_class_file() != the_class->get_cached_class_file()) { 4370 // 1. the_class doesn't have a cache yet, scratch_class does have a cache. 4371 // 2. The same class can be present twice in the scratch classes list or there 4372 // are multiple concurrent RetransformClasses calls on different threads. 4373 // the_class and scratch_class have the same cached bytes, but different buffers. 4374 // In such cases we need to deallocate one of the buffers. 4375 // 3. RedefineClasses and the_class has cached bytes from a previous transformation. 4376 // In the case we need to use class bytes from scratch_class. 4377 if (the_class->get_cached_class_file() != nullptr) { 4378 os::free(the_class->get_cached_class_file()); 4379 } 4380 the_class->set_cached_class_file(scratch_class->get_cached_class_file()); 4381 } 4382 4383 // null out in scratch class to not delete twice. The class to be redefined 4384 // always owns these bytes. 4385 scratch_class->set_cached_class_file(nullptr); 4386 4387 // Replace inner_classes 4388 Array<u2>* old_inner_classes = the_class->inner_classes(); 4389 the_class->set_inner_classes(scratch_class->inner_classes()); 4390 scratch_class->set_inner_classes(old_inner_classes); 4391 4392 // Initialize the vtable and interface table after 4393 // methods have been rewritten 4394 // no exception should happen here since we explicitly 4395 // do not check loader constraints. 4396 // compare_and_normalize_class_versions has already checked: 4397 // - classloaders unchanged, signatures unchanged 4398 // - all instanceKlasses for redefined classes reused & contents updated 4399 the_class->vtable().initialize_vtable(); 4400 the_class->itable().initialize_itable(); 4401 4402 // Update jmethodID cache if present. 4403 the_class->update_methods_jmethod_cache(); 4404 4405 // Copy the "source debug extension" attribute from new class version 4406 the_class->set_source_debug_extension( 4407 scratch_class->source_debug_extension(), 4408 scratch_class->source_debug_extension() == nullptr ? 0 : 4409 (int)strlen(scratch_class->source_debug_extension())); 4410 4411 // Use of javac -g could be different in the old and the new 4412 if (scratch_class->has_localvariable_table() != 4413 the_class->has_localvariable_table()) { 4414 the_class->set_has_localvariable_table(scratch_class->has_localvariable_table()); 4415 } 4416 4417 swap_annotations(the_class, scratch_class); 4418 4419 // Replace minor version number of class file 4420 u2 old_minor_version = the_class->constants()->minor_version(); 4421 the_class->constants()->set_minor_version(scratch_class->constants()->minor_version()); 4422 scratch_class->constants()->set_minor_version(old_minor_version); 4423 4424 // Replace major version number of class file 4425 u2 old_major_version = the_class->constants()->major_version(); 4426 the_class->constants()->set_major_version(scratch_class->constants()->major_version()); 4427 scratch_class->constants()->set_major_version(old_major_version); 4428 4429 // Replace CP indexes for class and name+type of enclosing method 4430 u2 old_class_idx = the_class->enclosing_method_class_index(); 4431 u2 old_method_idx = the_class->enclosing_method_method_index(); 4432 the_class->set_enclosing_method_indices( 4433 scratch_class->enclosing_method_class_index(), 4434 scratch_class->enclosing_method_method_index()); 4435 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx); 4436 4437 if (!the_class->has_been_redefined()) { 4438 the_class->set_has_been_redefined(); 4439 } 4440 4441 // Scratch class is unloaded but still needs cleaning, and skipping for CDS. 4442 scratch_class->set_is_scratch_class(); 4443 4444 // keep track of previous versions of this class 4445 the_class->add_previous_version(scratch_class, emcp_method_count); 4446 4447 _timer_rsc_phase1.stop(); 4448 if (log_is_enabled(Info, redefine, class, timer)) { 4449 _timer_rsc_phase2.start(); 4450 } 4451 4452 if (the_class->oop_map_cache() != nullptr) { 4453 // Flush references to any obsolete methods from the oop map cache 4454 // so that obsolete methods are not pinned. 4455 the_class->oop_map_cache()->flush_obsolete_entries(); 4456 } 4457 4458 increment_class_counter(the_class); 4459 4460 if (EventClassRedefinition::is_enabled()) { 4461 EventClassRedefinition event; 4462 event.set_classModificationCount(java_lang_Class::classRedefinedCount(the_class->java_mirror())); 4463 event.set_redefinedClass(the_class); 4464 event.set_redefinitionId(_id); 4465 event.commit(); 4466 } 4467 4468 { 4469 ResourceMark rm(current); 4470 // increment the classRedefinedCount field in the_class and in any 4471 // direct and indirect subclasses of the_class 4472 log_info(redefine, class, load) 4473 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)", 4474 the_class->external_name(), java_lang_Class::classRedefinedCount(the_class->java_mirror()), os::available_memory() >> 10); 4475 Events::log_redefinition(current, "redefined class name=%s, count=%d", 4476 the_class->external_name(), 4477 java_lang_Class::classRedefinedCount(the_class->java_mirror())); 4478 4479 } 4480 _timer_rsc_phase2.stop(); 4481 4482 } // end redefine_single_class() 4483 4484 4485 // Increment the classRedefinedCount field in the specific InstanceKlass 4486 // and in all direct and indirect subclasses. 4487 void VM_RedefineClasses::increment_class_counter(InstanceKlass* ik) { 4488 for (ClassHierarchyIterator iter(ik); !iter.done(); iter.next()) { 4489 // Only update instanceKlasses 4490 Klass* sub = iter.klass(); 4491 if (sub->is_instance_klass()) { 4492 oop class_mirror = InstanceKlass::cast(sub)->java_mirror(); 4493 Klass* class_oop = java_lang_Class::as_Klass(class_mirror); 4494 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1; 4495 java_lang_Class::set_classRedefinedCount(class_mirror, new_count); 4496 4497 if (class_oop != _the_class) { 4498 // _the_class count is printed at end of redefine_single_class() 4499 log_debug(redefine, class, subclass)("updated count in subclass=%s to %d", ik->external_name(), new_count); 4500 } 4501 } 4502 } 4503 } 4504 4505 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) { 4506 bool no_old_methods = true; // be optimistic 4507 4508 // Both array and instance classes have vtables. 4509 // a vtable should never contain old or obsolete methods 4510 ResourceMark rm(_thread); 4511 if (k->vtable_length() > 0 && 4512 !k->vtable().check_no_old_or_obsolete_entries()) { 4513 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 4514 log_trace(redefine, class, obsolete, metadata) 4515 ("klassVtable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s", 4516 k->signature_name()); 4517 k->vtable().dump_vtable(); 4518 } 4519 no_old_methods = false; 4520 } 4521 4522 if (k->is_instance_klass()) { 4523 HandleMark hm(_thread); 4524 InstanceKlass *ik = InstanceKlass::cast(k); 4525 4526 // an itable should never contain old or obsolete methods 4527 if (ik->itable_length() > 0 && 4528 !ik->itable().check_no_old_or_obsolete_entries()) { 4529 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 4530 log_trace(redefine, class, obsolete, metadata) 4531 ("klassItable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s", 4532 ik->signature_name()); 4533 ik->itable().dump_itable(); 4534 } 4535 no_old_methods = false; 4536 } 4537 4538 // the constant pool cache should never contain non-deleted old or obsolete methods 4539 if (ik->constants() != nullptr && 4540 ik->constants()->cache() != nullptr && 4541 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) { 4542 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 4543 log_trace(redefine, class, obsolete, metadata) 4544 ("cp-cache::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s", 4545 ik->signature_name()); 4546 ik->constants()->cache()->dump_cache(); 4547 } 4548 no_old_methods = false; 4549 } 4550 } 4551 4552 // print and fail guarantee if old methods are found. 4553 if (!no_old_methods) { 4554 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 4555 dump_methods(); 4556 } else { 4557 log_trace(redefine, class)("Use the '-Xlog:redefine+class*:' option " 4558 "to see more info about the following guarantee() failure."); 4559 } 4560 guarantee(false, "OLD and/or OBSOLETE method(s) found"); 4561 } 4562 } 4563 4564 u8 VM_RedefineClasses::next_id() { 4565 while (true) { 4566 u8 id = _id_counter; 4567 u8 next_id = id + 1; 4568 u8 result = Atomic::cmpxchg(&_id_counter, id, next_id); 4569 if (result == id) { 4570 return next_id; 4571 } 4572 } 4573 } 4574 4575 void VM_RedefineClasses::dump_methods() { 4576 int j; 4577 log_trace(redefine, class, dump)("_old_methods --"); 4578 for (j = 0; j < _old_methods->length(); ++j) { 4579 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4580 Method* m = _old_methods->at(j); 4581 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4582 m->access_flags().print_on(&log_stream); 4583 log_stream.print(" -- "); 4584 m->print_name(&log_stream); 4585 log_stream.cr(); 4586 } 4587 log_trace(redefine, class, dump)("_new_methods --"); 4588 for (j = 0; j < _new_methods->length(); ++j) { 4589 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4590 Method* m = _new_methods->at(j); 4591 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4592 m->access_flags().print_on(&log_stream); 4593 log_stream.print(" -- "); 4594 m->print_name(&log_stream); 4595 log_stream.cr(); 4596 } 4597 log_trace(redefine, class, dump)("_matching_methods --"); 4598 for (j = 0; j < _matching_methods_length; ++j) { 4599 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4600 Method* m = _matching_old_methods[j]; 4601 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4602 m->access_flags().print_on(&log_stream); 4603 log_stream.print(" -- "); 4604 m->print_name(); 4605 log_stream.cr(); 4606 4607 m = _matching_new_methods[j]; 4608 log_stream.print(" (%5d) ", m->vtable_index()); 4609 m->access_flags().print_on(&log_stream); 4610 log_stream.cr(); 4611 } 4612 log_trace(redefine, class, dump)("_deleted_methods --"); 4613 for (j = 0; j < _deleted_methods_length; ++j) { 4614 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4615 Method* m = _deleted_methods[j]; 4616 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4617 m->access_flags().print_on(&log_stream); 4618 log_stream.print(" -- "); 4619 m->print_name(&log_stream); 4620 log_stream.cr(); 4621 } 4622 log_trace(redefine, class, dump)("_added_methods --"); 4623 for (j = 0; j < _added_methods_length; ++j) { 4624 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4625 Method* m = _added_methods[j]; 4626 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4627 m->access_flags().print_on(&log_stream); 4628 log_stream.print(" -- "); 4629 m->print_name(&log_stream); 4630 log_stream.cr(); 4631 } 4632 } 4633 4634 void VM_RedefineClasses::print_on_error(outputStream* st) const { 4635 VM_Operation::print_on_error(st); 4636 if (_the_class != nullptr) { 4637 ResourceMark rm; 4638 st->print_cr(", redefining class %s", _the_class->external_name()); 4639 } 4640 }