1 /* 2 * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "cds/metaspaceShared.hpp" 27 #include "classfile/classFileStream.hpp" 28 #include "classfile/classLoaderDataGraph.hpp" 29 #include "classfile/classLoadInfo.hpp" 30 #include "classfile/javaClasses.inline.hpp" 31 #include "classfile/metadataOnStackMark.hpp" 32 #include "classfile/symbolTable.hpp" 33 #include "classfile/klassFactory.hpp" 34 #include "classfile/verifier.hpp" 35 #include "classfile/vmClasses.hpp" 36 #include "classfile/vmSymbols.hpp" 37 #include "code/codeCache.hpp" 38 #include "compiler/compileBroker.hpp" 39 #include "interpreter/oopMapCache.hpp" 40 #include "interpreter/rewriter.hpp" 41 #include "jfr/jfrEvents.hpp" 42 #include "logging/logStream.hpp" 43 #include "memory/metadataFactory.hpp" 44 #include "memory/resourceArea.hpp" 45 #include "memory/universe.hpp" 46 #include "oops/annotations.hpp" 47 #include "oops/constantPool.hpp" 48 #include "oops/fieldStreams.inline.hpp" 49 #include "oops/klass.inline.hpp" 50 #include "oops/klassVtable.hpp" 51 #include "oops/oop.inline.hpp" 52 #include "oops/recordComponent.hpp" 53 #include "prims/jvmtiImpl.hpp" 54 #include "prims/jvmtiRedefineClasses.hpp" 55 #include "prims/jvmtiThreadState.inline.hpp" 56 #include "prims/resolvedMethodTable.hpp" 57 #include "prims/methodComparator.hpp" 58 #include "runtime/atomic.hpp" 59 #include "runtime/deoptimization.hpp" 60 #include "runtime/handles.inline.hpp" 61 #include "runtime/jniHandles.inline.hpp" 62 #include "runtime/relocator.hpp" 63 #include "runtime/safepointVerifiers.hpp" 64 #include "utilities/bitMap.inline.hpp" 65 #include "utilities/events.hpp" 66 67 Array<Method*>* VM_RedefineClasses::_old_methods = NULL; 68 Array<Method*>* VM_RedefineClasses::_new_methods = NULL; 69 Method** VM_RedefineClasses::_matching_old_methods = NULL; 70 Method** VM_RedefineClasses::_matching_new_methods = NULL; 71 Method** VM_RedefineClasses::_deleted_methods = NULL; 72 Method** VM_RedefineClasses::_added_methods = NULL; 73 int VM_RedefineClasses::_matching_methods_length = 0; 74 int VM_RedefineClasses::_deleted_methods_length = 0; 75 int VM_RedefineClasses::_added_methods_length = 0; 76 77 // This flag is global as the constructor does not reset it: 78 bool VM_RedefineClasses::_has_redefined_Object = false; 79 u8 VM_RedefineClasses::_id_counter = 0; 80 81 VM_RedefineClasses::VM_RedefineClasses(jint class_count, 82 const jvmtiClassDefinition *class_defs, 83 JvmtiClassLoadKind class_load_kind) { 84 _class_count = class_count; 85 _class_defs = class_defs; 86 _class_load_kind = class_load_kind; 87 _any_class_has_resolved_methods = false; 88 _res = JVMTI_ERROR_NONE; 89 _the_class = NULL; 90 _id = next_id(); 91 } 92 93 static inline InstanceKlass* get_ik(jclass def) { 94 oop mirror = JNIHandles::resolve_non_null(def); 95 return InstanceKlass::cast(java_lang_Class::as_Klass(mirror)); 96 } 97 98 // If any of the classes are being redefined, wait 99 // Parallel constant pool merging leads to indeterminate constant pools. 100 void VM_RedefineClasses::lock_classes() { 101 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current()); 102 GrowableArray<Klass*>* redef_classes = state->get_classes_being_redefined(); 103 104 MonitorLocker ml(RedefineClasses_lock); 105 106 if (redef_classes == NULL) { 107 redef_classes = new(ResourceObj::C_HEAP, mtClass) GrowableArray<Klass*>(1, mtClass); 108 state->set_classes_being_redefined(redef_classes); 109 } 110 111 bool has_redefined; 112 do { 113 has_redefined = false; 114 // Go through classes each time until none are being redefined. Skip 115 // the ones that are being redefined by this thread currently. Class file 116 // load hook event may trigger new class redefine when we are redefining 117 // a class (after lock_classes()). 118 for (int i = 0; i < _class_count; i++) { 119 InstanceKlass* ik = get_ik(_class_defs[i].klass); 120 // Check if we are currently redefining the class in this thread already. 121 if (redef_classes->contains(ik)) { 122 assert(ik->is_being_redefined(), "sanity"); 123 } else { 124 if (ik->is_being_redefined()) { 125 ml.wait(); 126 has_redefined = true; 127 break; // for loop 128 } 129 } 130 } 131 } while (has_redefined); 132 133 for (int i = 0; i < _class_count; i++) { 134 InstanceKlass* ik = get_ik(_class_defs[i].klass); 135 redef_classes->push(ik); // Add to the _classes_being_redefined list 136 ik->set_is_being_redefined(true); 137 } 138 ml.notify_all(); 139 } 140 141 void VM_RedefineClasses::unlock_classes() { 142 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current()); 143 GrowableArray<Klass*>* redef_classes = state->get_classes_being_redefined(); 144 assert(redef_classes != NULL, "_classes_being_redefined is not allocated"); 145 146 MonitorLocker ml(RedefineClasses_lock); 147 148 for (int i = _class_count - 1; i >= 0; i--) { 149 InstanceKlass* def_ik = get_ik(_class_defs[i].klass); 150 if (redef_classes->length() > 0) { 151 // Remove the class from _classes_being_redefined list 152 Klass* k = redef_classes->pop(); 153 assert(def_ik == k, "unlocking wrong class"); 154 } 155 assert(def_ik->is_being_redefined(), 156 "should be being redefined to get here"); 157 158 // Unlock after we finish all redefines for this class within 159 // the thread. Same class can be pushed to the list multiple 160 // times (not more than once by each recursive redefinition). 161 if (!redef_classes->contains(def_ik)) { 162 def_ik->set_is_being_redefined(false); 163 } 164 } 165 ml.notify_all(); 166 } 167 168 bool VM_RedefineClasses::doit_prologue() { 169 if (_class_count == 0) { 170 _res = JVMTI_ERROR_NONE; 171 return false; 172 } 173 if (_class_defs == NULL) { 174 _res = JVMTI_ERROR_NULL_POINTER; 175 return false; 176 } 177 178 for (int i = 0; i < _class_count; i++) { 179 if (_class_defs[i].klass == NULL) { 180 _res = JVMTI_ERROR_INVALID_CLASS; 181 return false; 182 } 183 if (_class_defs[i].class_byte_count == 0) { 184 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT; 185 return false; 186 } 187 if (_class_defs[i].class_bytes == NULL) { 188 _res = JVMTI_ERROR_NULL_POINTER; 189 return false; 190 } 191 192 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass); 193 // classes for primitives, arrays, and hidden classes 194 // cannot be redefined. 195 if (!is_modifiable_class(mirror)) { 196 _res = JVMTI_ERROR_UNMODIFIABLE_CLASS; 197 return false; 198 } 199 } 200 201 // Start timer after all the sanity checks; not quite accurate, but 202 // better than adding a bunch of stop() calls. 203 if (log_is_enabled(Info, redefine, class, timer)) { 204 _timer_vm_op_prologue.start(); 205 } 206 207 lock_classes(); 208 // We first load new class versions in the prologue, because somewhere down the 209 // call chain it is required that the current thread is a Java thread. 210 _res = load_new_class_versions(); 211 if (_res != JVMTI_ERROR_NONE) { 212 // free any successfully created classes, since none are redefined 213 for (int i = 0; i < _class_count; i++) { 214 if (_scratch_classes[i] != NULL) { 215 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data(); 216 // Free the memory for this class at class unloading time. Not before 217 // because CMS might think this is still live. 218 InstanceKlass* ik = get_ik(_class_defs[i].klass); 219 if (ik->get_cached_class_file() == _scratch_classes[i]->get_cached_class_file()) { 220 // Don't double-free cached_class_file copied from the original class if error. 221 _scratch_classes[i]->set_cached_class_file(NULL); 222 } 223 cld->add_to_deallocate_list(InstanceKlass::cast(_scratch_classes[i])); 224 } 225 } 226 // Free os::malloc allocated memory in load_new_class_version. 227 os::free(_scratch_classes); 228 _timer_vm_op_prologue.stop(); 229 unlock_classes(); 230 return false; 231 } 232 233 _timer_vm_op_prologue.stop(); 234 return true; 235 } 236 237 void VM_RedefineClasses::doit() { 238 Thread* current = Thread::current(); 239 240 #if INCLUDE_CDS 241 if (UseSharedSpaces) { 242 // Sharing is enabled so we remap the shared readonly space to 243 // shared readwrite, private just in case we need to redefine 244 // a shared class. We do the remap during the doit() phase of 245 // the safepoint to be safer. 246 if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) { 247 log_info(redefine, class, load)("failed to remap shared readonly space to readwrite, private"); 248 _res = JVMTI_ERROR_INTERNAL; 249 return; 250 } 251 } 252 #endif 253 254 // Mark methods seen on stack and everywhere else so old methods are not 255 // cleaned up if they're on the stack. 256 MetadataOnStackMark md_on_stack(/*walk_all_metadata*/true, /*redefinition_walk*/true); 257 HandleMark hm(current); // make sure any handles created are deleted 258 // before the stack walk again. 259 260 for (int i = 0; i < _class_count; i++) { 261 redefine_single_class(current, _class_defs[i].klass, _scratch_classes[i]); 262 } 263 264 // Flush all compiled code that depends on the classes redefined. 265 flush_dependent_code(); 266 267 // Adjust constantpool caches and vtables for all classes 268 // that reference methods of the evolved classes. 269 // Have to do this after all classes are redefined and all methods that 270 // are redefined are marked as old. 271 AdjustAndCleanMetadata adjust_and_clean_metadata(current); 272 ClassLoaderDataGraph::classes_do(&adjust_and_clean_metadata); 273 274 // JSR-292 support 275 if (_any_class_has_resolved_methods) { 276 bool trace_name_printed = false; 277 ResolvedMethodTable::adjust_method_entries(&trace_name_printed); 278 } 279 280 // Increment flag indicating that some invariants are no longer true. 281 // See jvmtiExport.hpp for detailed explanation. 282 JvmtiExport::increment_redefinition_count(); 283 284 // check_class() is optionally called for product bits, but is 285 // always called for non-product bits. 286 #ifdef PRODUCT 287 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 288 #endif 289 log_trace(redefine, class, obsolete, metadata)("calling check_class"); 290 CheckClass check_class(current); 291 ClassLoaderDataGraph::classes_do(&check_class); 292 #ifdef PRODUCT 293 } 294 #endif 295 296 // Clean up any metadata now unreferenced while MetadataOnStackMark is set. 297 ClassLoaderDataGraph::clean_deallocate_lists(false); 298 } 299 300 void VM_RedefineClasses::doit_epilogue() { 301 unlock_classes(); 302 303 // Free os::malloc allocated memory. 304 os::free(_scratch_classes); 305 306 // Reset the_class to null for error printing. 307 _the_class = NULL; 308 309 if (log_is_enabled(Info, redefine, class, timer)) { 310 // Used to have separate timers for "doit" and "all", but the timer 311 // overhead skewed the measurements. 312 julong doit_time = _timer_rsc_phase1.milliseconds() + 313 _timer_rsc_phase2.milliseconds(); 314 julong all_time = _timer_vm_op_prologue.milliseconds() + doit_time; 315 316 log_info(redefine, class, timer) 317 ("vm_op: all=" JULONG_FORMAT " prologue=" JULONG_FORMAT " doit=" JULONG_FORMAT, 318 all_time, (julong)_timer_vm_op_prologue.milliseconds(), doit_time); 319 log_info(redefine, class, timer) 320 ("redefine_single_class: phase1=" JULONG_FORMAT " phase2=" JULONG_FORMAT, 321 (julong)_timer_rsc_phase1.milliseconds(), (julong)_timer_rsc_phase2.milliseconds()); 322 } 323 } 324 325 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) { 326 // classes for primitives cannot be redefined 327 if (java_lang_Class::is_primitive(klass_mirror)) { 328 return false; 329 } 330 Klass* k = java_lang_Class::as_Klass(klass_mirror); 331 // classes for arrays cannot be redefined 332 if (k == NULL || !k->is_instance_klass()) { 333 return false; 334 } 335 336 // Cannot redefine or retransform a hidden class. 337 if (InstanceKlass::cast(k)->is_hidden()) { 338 return false; 339 } 340 return true; 341 } 342 343 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p 344 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For 345 // direct CP entries, there is just the current entry to append. For 346 // indirect and double-indirect CP entries, there are zero or more 347 // referenced CP entries along with the current entry to append. 348 // Indirect and double-indirect CP entries are handled by recursive 349 // calls to append_entry() as needed. The referenced CP entries are 350 // always appended to *merge_cp_p before the referee CP entry. These 351 // referenced CP entries may already exist in *merge_cp_p in which case 352 // there is nothing extra to append and only the current entry is 353 // appended. 354 void VM_RedefineClasses::append_entry(const constantPoolHandle& scratch_cp, 355 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) { 356 357 // append is different depending on entry tag type 358 switch (scratch_cp->tag_at(scratch_i).value()) { 359 360 // The old verifier is implemented outside the VM. It loads classes, 361 // but does not resolve constant pool entries directly so we never 362 // see Class entries here with the old verifier. Similarly the old 363 // verifier does not like Class entries in the input constant pool. 364 // The split-verifier is implemented in the VM so it can optionally 365 // and directly resolve constant pool entries to load classes. The 366 // split-verifier can accept either Class entries or UnresolvedClass 367 // entries in the input constant pool. We revert the appended copy 368 // back to UnresolvedClass so that either verifier will be happy 369 // with the constant pool entry. 370 // 371 // this is an indirect CP entry so it needs special handling 372 case JVM_CONSTANT_Class: 373 case JVM_CONSTANT_UnresolvedClass: 374 { 375 int name_i = scratch_cp->klass_name_index_at(scratch_i); 376 int new_name_i = find_or_append_indirect_entry(scratch_cp, name_i, merge_cp_p, 377 merge_cp_length_p); 378 379 if (new_name_i != name_i) { 380 log_trace(redefine, class, constantpool) 381 ("Class entry@%d name_index change: %d to %d", 382 *merge_cp_length_p, name_i, new_name_i); 383 } 384 385 (*merge_cp_p)->temp_unresolved_klass_at_put(*merge_cp_length_p, new_name_i); 386 if (scratch_i != *merge_cp_length_p) { 387 // The new entry in *merge_cp_p is at a different index than 388 // the new entry in scratch_cp so we need to map the index values. 389 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 390 } 391 (*merge_cp_length_p)++; 392 } break; 393 394 // these are direct CP entries so they can be directly appended, 395 // but double and long take two constant pool entries 396 case JVM_CONSTANT_Double: // fall through 397 case JVM_CONSTANT_Long: 398 { 399 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p); 400 401 if (scratch_i != *merge_cp_length_p) { 402 // The new entry in *merge_cp_p is at a different index than 403 // the new entry in scratch_cp so we need to map the index values. 404 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 405 } 406 (*merge_cp_length_p) += 2; 407 } break; 408 409 // these are direct CP entries so they can be directly appended 410 case JVM_CONSTANT_Float: // fall through 411 case JVM_CONSTANT_Integer: // fall through 412 case JVM_CONSTANT_Utf8: // fall through 413 414 // This was an indirect CP entry, but it has been changed into 415 // Symbol*s so this entry can be directly appended. 416 case JVM_CONSTANT_String: // fall through 417 { 418 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p); 419 420 if (scratch_i != *merge_cp_length_p) { 421 // The new entry in *merge_cp_p is at a different index than 422 // the new entry in scratch_cp so we need to map the index values. 423 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 424 } 425 (*merge_cp_length_p)++; 426 } break; 427 428 // this is an indirect CP entry so it needs special handling 429 case JVM_CONSTANT_NameAndType: 430 { 431 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i); 432 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p, 433 merge_cp_length_p); 434 435 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i); 436 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i, 437 merge_cp_p, merge_cp_length_p); 438 439 // If the referenced entries already exist in *merge_cp_p, then 440 // both new_name_ref_i and new_signature_ref_i will both be 0. 441 // In that case, all we are appending is the current entry. 442 if (new_name_ref_i != name_ref_i) { 443 log_trace(redefine, class, constantpool) 444 ("NameAndType entry@%d name_ref_index change: %d to %d", 445 *merge_cp_length_p, name_ref_i, new_name_ref_i); 446 } 447 if (new_signature_ref_i != signature_ref_i) { 448 log_trace(redefine, class, constantpool) 449 ("NameAndType entry@%d signature_ref_index change: %d to %d", 450 *merge_cp_length_p, signature_ref_i, new_signature_ref_i); 451 } 452 453 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p, 454 new_name_ref_i, new_signature_ref_i); 455 if (scratch_i != *merge_cp_length_p) { 456 // The new entry in *merge_cp_p is at a different index than 457 // the new entry in scratch_cp so we need to map the index values. 458 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 459 } 460 (*merge_cp_length_p)++; 461 } break; 462 463 // this is a double-indirect CP entry so it needs special handling 464 case JVM_CONSTANT_Fieldref: // fall through 465 case JVM_CONSTANT_InterfaceMethodref: // fall through 466 case JVM_CONSTANT_Methodref: 467 { 468 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i); 469 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i, 470 merge_cp_p, merge_cp_length_p); 471 472 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i); 473 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i, 474 merge_cp_p, merge_cp_length_p); 475 476 const char *entry_name = NULL; 477 switch (scratch_cp->tag_at(scratch_i).value()) { 478 case JVM_CONSTANT_Fieldref: 479 entry_name = "Fieldref"; 480 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i, 481 new_name_and_type_ref_i); 482 break; 483 case JVM_CONSTANT_InterfaceMethodref: 484 entry_name = "IFMethodref"; 485 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p, 486 new_klass_ref_i, new_name_and_type_ref_i); 487 break; 488 case JVM_CONSTANT_Methodref: 489 entry_name = "Methodref"; 490 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i, 491 new_name_and_type_ref_i); 492 break; 493 default: 494 guarantee(false, "bad switch"); 495 break; 496 } 497 498 if (klass_ref_i != new_klass_ref_i) { 499 log_trace(redefine, class, constantpool) 500 ("%s entry@%d class_index changed: %d to %d", entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i); 501 } 502 if (name_and_type_ref_i != new_name_and_type_ref_i) { 503 log_trace(redefine, class, constantpool) 504 ("%s entry@%d name_and_type_index changed: %d to %d", 505 entry_name, *merge_cp_length_p, name_and_type_ref_i, new_name_and_type_ref_i); 506 } 507 508 if (scratch_i != *merge_cp_length_p) { 509 // The new entry in *merge_cp_p is at a different index than 510 // the new entry in scratch_cp so we need to map the index values. 511 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 512 } 513 (*merge_cp_length_p)++; 514 } break; 515 516 // this is an indirect CP entry so it needs special handling 517 case JVM_CONSTANT_MethodType: 518 { 519 int ref_i = scratch_cp->method_type_index_at(scratch_i); 520 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p, 521 merge_cp_length_p); 522 if (new_ref_i != ref_i) { 523 log_trace(redefine, class, constantpool) 524 ("MethodType entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i); 525 } 526 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i); 527 if (scratch_i != *merge_cp_length_p) { 528 // The new entry in *merge_cp_p is at a different index than 529 // the new entry in scratch_cp so we need to map the index values. 530 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 531 } 532 (*merge_cp_length_p)++; 533 } break; 534 535 // this is an indirect CP entry so it needs special handling 536 case JVM_CONSTANT_MethodHandle: 537 { 538 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i); 539 int ref_i = scratch_cp->method_handle_index_at(scratch_i); 540 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p, 541 merge_cp_length_p); 542 if (new_ref_i != ref_i) { 543 log_trace(redefine, class, constantpool) 544 ("MethodHandle entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i); 545 } 546 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i); 547 if (scratch_i != *merge_cp_length_p) { 548 // The new entry in *merge_cp_p is at a different index than 549 // the new entry in scratch_cp so we need to map the index values. 550 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 551 } 552 (*merge_cp_length_p)++; 553 } break; 554 555 // this is an indirect CP entry so it needs special handling 556 case JVM_CONSTANT_Dynamic: // fall through 557 case JVM_CONSTANT_InvokeDynamic: 558 { 559 // Index of the bootstrap specifier in the operands array 560 int old_bs_i = scratch_cp->bootstrap_methods_attribute_index(scratch_i); 561 int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p, 562 merge_cp_length_p); 563 // The bootstrap method NameAndType_info index 564 int old_ref_i = scratch_cp->bootstrap_name_and_type_ref_index_at(scratch_i); 565 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p, 566 merge_cp_length_p); 567 if (new_bs_i != old_bs_i) { 568 log_trace(redefine, class, constantpool) 569 ("Dynamic entry@%d bootstrap_method_attr_index change: %d to %d", 570 *merge_cp_length_p, old_bs_i, new_bs_i); 571 } 572 if (new_ref_i != old_ref_i) { 573 log_trace(redefine, class, constantpool) 574 ("Dynamic entry@%d name_and_type_index change: %d to %d", *merge_cp_length_p, old_ref_i, new_ref_i); 575 } 576 577 if (scratch_cp->tag_at(scratch_i).is_dynamic_constant()) 578 (*merge_cp_p)->dynamic_constant_at_put(*merge_cp_length_p, new_bs_i, new_ref_i); 579 else 580 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i); 581 if (scratch_i != *merge_cp_length_p) { 582 // The new entry in *merge_cp_p is at a different index than 583 // the new entry in scratch_cp so we need to map the index values. 584 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 585 } 586 (*merge_cp_length_p)++; 587 } break; 588 589 // At this stage, Class or UnresolvedClass could be in scratch_cp, but not 590 // ClassIndex 591 case JVM_CONSTANT_ClassIndex: // fall through 592 593 // Invalid is used as the tag for the second constant pool entry 594 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should 595 // not be seen by itself. 596 case JVM_CONSTANT_Invalid: // fall through 597 598 // At this stage, String could be here, but not StringIndex 599 case JVM_CONSTANT_StringIndex: // fall through 600 601 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be 602 // here 603 case JVM_CONSTANT_UnresolvedClassInError: // fall through 604 605 default: 606 { 607 // leave a breadcrumb 608 jbyte bad_value = scratch_cp->tag_at(scratch_i).value(); 609 ShouldNotReachHere(); 610 } break; 611 } // end switch tag value 612 } // end append_entry() 613 614 615 int VM_RedefineClasses::find_or_append_indirect_entry(const constantPoolHandle& scratch_cp, 616 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) { 617 618 int new_ref_i = ref_i; 619 bool match = (ref_i < *merge_cp_length_p) && 620 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i); 621 622 if (!match) { 623 // forward reference in *merge_cp_p or not a direct match 624 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p); 625 if (found_i != 0) { 626 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree"); 627 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry. 628 new_ref_i = found_i; 629 map_index(scratch_cp, ref_i, found_i); 630 } else { 631 // no match found so we have to append this entry to *merge_cp_p 632 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p); 633 // The above call to append_entry() can only append one entry 634 // so the post call query of *merge_cp_length_p is only for 635 // the sake of consistency. 636 new_ref_i = *merge_cp_length_p - 1; 637 } 638 } 639 640 return new_ref_i; 641 } // end find_or_append_indirect_entry() 642 643 644 // Append a bootstrap specifier into the merge_cp operands that is semantically equal 645 // to the scratch_cp operands bootstrap specifier passed by the old_bs_i index. 646 // Recursively append new merge_cp entries referenced by the new bootstrap specifier. 647 void VM_RedefineClasses::append_operand(const constantPoolHandle& scratch_cp, int old_bs_i, 648 constantPoolHandle *merge_cp_p, int *merge_cp_length_p) { 649 650 int old_ref_i = scratch_cp->operand_bootstrap_method_ref_index_at(old_bs_i); 651 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p, 652 merge_cp_length_p); 653 if (new_ref_i != old_ref_i) { 654 log_trace(redefine, class, constantpool) 655 ("operands entry@%d bootstrap method ref_index change: %d to %d", _operands_cur_length, old_ref_i, new_ref_i); 656 } 657 658 Array<u2>* merge_ops = (*merge_cp_p)->operands(); 659 int new_bs_i = _operands_cur_length; 660 // We have _operands_cur_length == 0 when the merge_cp operands is empty yet. 661 // However, the operand_offset_at(0) was set in the extend_operands() call. 662 int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0) 663 : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1); 664 int argc = scratch_cp->operand_argument_count_at(old_bs_i); 665 666 ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base); 667 merge_ops->at_put(new_base++, new_ref_i); 668 merge_ops->at_put(new_base++, argc); 669 670 for (int i = 0; i < argc; i++) { 671 int old_arg_ref_i = scratch_cp->operand_argument_index_at(old_bs_i, i); 672 int new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p, 673 merge_cp_length_p); 674 merge_ops->at_put(new_base++, new_arg_ref_i); 675 if (new_arg_ref_i != old_arg_ref_i) { 676 log_trace(redefine, class, constantpool) 677 ("operands entry@%d bootstrap method argument ref_index change: %d to %d", 678 _operands_cur_length, old_arg_ref_i, new_arg_ref_i); 679 } 680 } 681 if (old_bs_i != _operands_cur_length) { 682 // The bootstrap specifier in *merge_cp_p is at a different index than 683 // that in scratch_cp so we need to map the index values. 684 map_operand_index(old_bs_i, new_bs_i); 685 } 686 _operands_cur_length++; 687 } // end append_operand() 688 689 690 int VM_RedefineClasses::find_or_append_operand(const constantPoolHandle& scratch_cp, 691 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) { 692 693 int new_bs_i = old_bs_i; // bootstrap specifier index 694 bool match = (old_bs_i < _operands_cur_length) && 695 scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i); 696 697 if (!match) { 698 // forward reference in *merge_cp_p or not a direct match 699 int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p, 700 _operands_cur_length); 701 if (found_i != -1) { 702 guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree"); 703 // found a matching operand somewhere else in *merge_cp_p so just need a mapping 704 new_bs_i = found_i; 705 map_operand_index(old_bs_i, found_i); 706 } else { 707 // no match found so we have to append this bootstrap specifier to *merge_cp_p 708 append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p); 709 new_bs_i = _operands_cur_length - 1; 710 } 711 } 712 return new_bs_i; 713 } // end find_or_append_operand() 714 715 716 void VM_RedefineClasses::finalize_operands_merge(const constantPoolHandle& merge_cp, TRAPS) { 717 if (merge_cp->operands() == NULL) { 718 return; 719 } 720 // Shrink the merge_cp operands 721 merge_cp->shrink_operands(_operands_cur_length, CHECK); 722 723 if (log_is_enabled(Trace, redefine, class, constantpool)) { 724 // don't want to loop unless we are tracing 725 int count = 0; 726 for (int i = 1; i < _operands_index_map_p->length(); i++) { 727 int value = _operands_index_map_p->at(i); 728 if (value != -1) { 729 log_trace(redefine, class, constantpool)("operands_index_map[%d]: old=%d new=%d", count, i, value); 730 count++; 731 } 732 } 733 } 734 // Clean-up 735 _operands_index_map_p = NULL; 736 _operands_cur_length = 0; 737 _operands_index_map_count = 0; 738 } // end finalize_operands_merge() 739 740 // Symbol* comparator for qsort 741 // The caller must have an active ResourceMark. 742 static int symcmp(const void* a, const void* b) { 743 char* astr = (*(Symbol**)a)->as_C_string(); 744 char* bstr = (*(Symbol**)b)->as_C_string(); 745 return strcmp(astr, bstr); 746 } 747 748 // The caller must have an active ResourceMark. 749 static jvmtiError check_attribute_arrays(const char* attr_name, 750 InstanceKlass* the_class, InstanceKlass* scratch_class, 751 Array<u2>* the_array, Array<u2>* scr_array) { 752 bool the_array_exists = the_array != Universe::the_empty_short_array(); 753 bool scr_array_exists = scr_array != Universe::the_empty_short_array(); 754 755 int array_len = the_array->length(); 756 if (the_array_exists && scr_array_exists) { 757 if (array_len != scr_array->length()) { 758 log_trace(redefine, class) 759 ("redefined class %s attribute change error: %s len=%d changed to len=%d", 760 the_class->external_name(), attr_name, array_len, scr_array->length()); 761 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 762 } 763 764 // The order of entries in the attribute array is not specified so we 765 // have to explicitly check for the same contents. We do this by copying 766 // the referenced symbols into their own arrays, sorting them and then 767 // comparing each element pair. 768 769 Symbol** the_syms = NEW_RESOURCE_ARRAY_RETURN_NULL(Symbol*, array_len); 770 Symbol** scr_syms = NEW_RESOURCE_ARRAY_RETURN_NULL(Symbol*, array_len); 771 772 if (the_syms == NULL || scr_syms == NULL) { 773 return JVMTI_ERROR_OUT_OF_MEMORY; 774 } 775 776 for (int i = 0; i < array_len; i++) { 777 int the_cp_index = the_array->at(i); 778 int scr_cp_index = scr_array->at(i); 779 the_syms[i] = the_class->constants()->klass_name_at(the_cp_index); 780 scr_syms[i] = scratch_class->constants()->klass_name_at(scr_cp_index); 781 } 782 783 qsort(the_syms, array_len, sizeof(Symbol*), symcmp); 784 qsort(scr_syms, array_len, sizeof(Symbol*), symcmp); 785 786 for (int i = 0; i < array_len; i++) { 787 if (the_syms[i] != scr_syms[i]) { 788 log_info(redefine, class) 789 ("redefined class %s attribute change error: %s[%d]: %s changed to %s", 790 the_class->external_name(), attr_name, i, 791 the_syms[i]->as_C_string(), scr_syms[i]->as_C_string()); 792 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 793 } 794 } 795 } else if (the_array_exists ^ scr_array_exists) { 796 const char* action_str = (the_array_exists) ? "removed" : "added"; 797 log_info(redefine, class) 798 ("redefined class %s attribute change error: %s attribute %s", 799 the_class->external_name(), attr_name, action_str); 800 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 801 } 802 return JVMTI_ERROR_NONE; 803 } 804 805 static jvmtiError check_nest_attributes(InstanceKlass* the_class, 806 InstanceKlass* scratch_class) { 807 // Check whether the class NestHost attribute has been changed. 808 Thread* thread = Thread::current(); 809 ResourceMark rm(thread); 810 u2 the_nest_host_idx = the_class->nest_host_index(); 811 u2 scr_nest_host_idx = scratch_class->nest_host_index(); 812 813 if (the_nest_host_idx != 0 && scr_nest_host_idx != 0) { 814 Symbol* the_sym = the_class->constants()->klass_name_at(the_nest_host_idx); 815 Symbol* scr_sym = scratch_class->constants()->klass_name_at(scr_nest_host_idx); 816 if (the_sym != scr_sym) { 817 log_info(redefine, class, nestmates) 818 ("redefined class %s attribute change error: NestHost class: %s replaced with: %s", 819 the_class->external_name(), the_sym->as_C_string(), scr_sym->as_C_string()); 820 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 821 } 822 } else if ((the_nest_host_idx == 0) ^ (scr_nest_host_idx == 0)) { 823 const char* action_str = (the_nest_host_idx != 0) ? "removed" : "added"; 824 log_info(redefine, class, nestmates) 825 ("redefined class %s attribute change error: NestHost attribute %s", 826 the_class->external_name(), action_str); 827 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 828 } 829 830 // Check whether the class NestMembers attribute has been changed. 831 return check_attribute_arrays("NestMembers", 832 the_class, scratch_class, 833 the_class->nest_members(), 834 scratch_class->nest_members()); 835 } 836 837 // Return an error status if the class Record attribute was changed. 838 static jvmtiError check_record_attribute(InstanceKlass* the_class, InstanceKlass* scratch_class) { 839 // Get lists of record components. 840 Array<RecordComponent*>* the_record = the_class->record_components(); 841 Array<RecordComponent*>* scr_record = scratch_class->record_components(); 842 bool the_record_exists = the_record != NULL; 843 bool scr_record_exists = scr_record != NULL; 844 845 if (the_record_exists && scr_record_exists) { 846 int the_num_components = the_record->length(); 847 int scr_num_components = scr_record->length(); 848 if (the_num_components != scr_num_components) { 849 log_info(redefine, class, record) 850 ("redefined class %s attribute change error: Record num_components=%d changed to num_components=%d", 851 the_class->external_name(), the_num_components, scr_num_components); 852 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 853 } 854 855 // Compare each field in each record component. 856 ConstantPool* the_cp = the_class->constants(); 857 ConstantPool* scr_cp = scratch_class->constants(); 858 for (int x = 0; x < the_num_components; x++) { 859 RecordComponent* the_component = the_record->at(x); 860 RecordComponent* scr_component = scr_record->at(x); 861 const Symbol* const the_name = the_cp->symbol_at(the_component->name_index()); 862 const Symbol* const scr_name = scr_cp->symbol_at(scr_component->name_index()); 863 const Symbol* const the_descr = the_cp->symbol_at(the_component->descriptor_index()); 864 const Symbol* const scr_descr = scr_cp->symbol_at(scr_component->descriptor_index()); 865 if (the_name != scr_name || the_descr != scr_descr) { 866 log_info(redefine, class, record) 867 ("redefined class %s attribute change error: Record name_index, descriptor_index, and/or attributes_count changed", 868 the_class->external_name()); 869 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 870 } 871 872 int the_gen_sig = the_component->generic_signature_index(); 873 int scr_gen_sig = scr_component->generic_signature_index(); 874 const Symbol* const the_gen_sig_sym = (the_gen_sig == 0 ? NULL : 875 the_cp->symbol_at(the_component->generic_signature_index())); 876 const Symbol* const scr_gen_sig_sym = (scr_gen_sig == 0 ? NULL : 877 scr_cp->symbol_at(scr_component->generic_signature_index())); 878 if (the_gen_sig_sym != scr_gen_sig_sym) { 879 log_info(redefine, class, record) 880 ("redefined class %s attribute change error: Record generic_signature attribute changed", 881 the_class->external_name()); 882 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 883 } 884 885 // It's okay if a record component's annotations were changed. 886 } 887 888 } else if (the_record_exists ^ scr_record_exists) { 889 const char* action_str = (the_record_exists) ? "removed" : "added"; 890 log_info(redefine, class, record) 891 ("redefined class %s attribute change error: Record attribute %s", 892 the_class->external_name(), action_str); 893 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 894 } 895 896 return JVMTI_ERROR_NONE; 897 } 898 899 900 static jvmtiError check_permitted_subclasses_attribute(InstanceKlass* the_class, 901 InstanceKlass* scratch_class) { 902 Thread* thread = Thread::current(); 903 ResourceMark rm(thread); 904 905 // Check whether the class PermittedSubclasses attribute has been changed. 906 return check_attribute_arrays("PermittedSubclasses", 907 the_class, scratch_class, 908 the_class->permitted_subclasses(), 909 scratch_class->permitted_subclasses()); 910 } 911 912 static bool can_add_or_delete(Method* m) { 913 // Compatibility mode 914 return (AllowRedefinitionToAddDeleteMethods && 915 (m->is_private() && (m->is_static() || m->is_final()))); 916 } 917 918 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions( 919 InstanceKlass* the_class, 920 InstanceKlass* scratch_class) { 921 int i; 922 923 // Check superclasses, or rather their names, since superclasses themselves can be 924 // requested to replace. 925 // Check for NULL superclass first since this might be java.lang.Object 926 if (the_class->super() != scratch_class->super() && 927 (the_class->super() == NULL || scratch_class->super() == NULL || 928 the_class->super()->name() != 929 scratch_class->super()->name())) { 930 log_info(redefine, class, normalize) 931 ("redefined class %s superclass change error: superclass changed from %s to %s.", 932 the_class->external_name(), 933 the_class->super() == NULL ? "NULL" : the_class->super()->external_name(), 934 scratch_class->super() == NULL ? "NULL" : scratch_class->super()->external_name()); 935 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 936 } 937 938 // Check if the number, names and order of directly implemented interfaces are the same. 939 // I think in principle we should just check if the sets of names of directly implemented 940 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the 941 // .java file, also changes in .class file) should not matter. However, comparing sets is 942 // technically a bit more difficult, and, more importantly, I am not sure at present that the 943 // order of interfaces does not matter on the implementation level, i.e. that the VM does not 944 // rely on it somewhere. 945 Array<InstanceKlass*>* k_interfaces = the_class->local_interfaces(); 946 Array<InstanceKlass*>* k_new_interfaces = scratch_class->local_interfaces(); 947 int n_intfs = k_interfaces->length(); 948 if (n_intfs != k_new_interfaces->length()) { 949 log_info(redefine, class, normalize) 950 ("redefined class %s interfaces change error: number of implemented interfaces changed from %d to %d.", 951 the_class->external_name(), n_intfs, k_new_interfaces->length()); 952 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 953 } 954 for (i = 0; i < n_intfs; i++) { 955 if (k_interfaces->at(i)->name() != 956 k_new_interfaces->at(i)->name()) { 957 log_info(redefine, class, normalize) 958 ("redefined class %s interfaces change error: interface changed from %s to %s.", 959 the_class->external_name(), 960 k_interfaces->at(i)->external_name(), k_new_interfaces->at(i)->external_name()); 961 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 962 } 963 } 964 965 // Check whether class is in the error init state. 966 if (the_class->is_in_error_state()) { 967 log_info(redefine, class, normalize) 968 ("redefined class %s is in error init state.", the_class->external_name()); 969 // TBD #5057930: special error code is needed in 1.6 970 return JVMTI_ERROR_INVALID_CLASS; 971 } 972 973 // Check whether the nest-related attributes have been changed. 974 jvmtiError err = check_nest_attributes(the_class, scratch_class); 975 if (err != JVMTI_ERROR_NONE) { 976 return err; 977 } 978 979 // Check whether the Record attribute has been changed. 980 err = check_record_attribute(the_class, scratch_class); 981 if (err != JVMTI_ERROR_NONE) { 982 return err; 983 } 984 985 // Check whether the PermittedSubclasses attribute has been changed. 986 err = check_permitted_subclasses_attribute(the_class, scratch_class); 987 if (err != JVMTI_ERROR_NONE) { 988 return err; 989 } 990 991 // Check whether class modifiers are the same. 992 jushort old_flags = (jushort) the_class->access_flags().get_flags(); 993 jushort new_flags = (jushort) scratch_class->access_flags().get_flags(); 994 if (old_flags != new_flags) { 995 log_info(redefine, class, normalize) 996 ("redefined class %s modifiers change error: modifiers changed from %d to %d.", 997 the_class->external_name(), old_flags, new_flags); 998 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED; 999 } 1000 1001 // Check if the number, names, types and order of fields declared in these classes 1002 // are the same. 1003 JavaFieldStream old_fs(the_class); 1004 JavaFieldStream new_fs(scratch_class); 1005 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) { 1006 // name and signature 1007 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index()); 1008 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index()); 1009 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index()); 1010 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index()); 1011 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) { 1012 log_info(redefine, class, normalize) 1013 ("redefined class %s fields change error: field %s %s changed to %s %s.", 1014 the_class->external_name(), 1015 sig_sym1->as_C_string(), name_sym1->as_C_string(), 1016 sig_sym2->as_C_string(), name_sym2->as_C_string()); 1017 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 1018 } 1019 // offset 1020 if (old_fs.offset() != new_fs.offset()) { 1021 log_info(redefine, class, normalize) 1022 ("redefined class %s field %s change error: offset changed from %d to %d.", 1023 the_class->external_name(), name_sym2->as_C_string(), old_fs.offset(), new_fs.offset()); 1024 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 1025 } 1026 // access 1027 old_flags = old_fs.access_flags().as_short(); 1028 new_flags = new_fs.access_flags().as_short(); 1029 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) { 1030 log_info(redefine, class, normalize) 1031 ("redefined class %s field %s change error: modifiers changed from %d to %d.", 1032 the_class->external_name(), name_sym2->as_C_string(), old_flags, new_flags); 1033 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 1034 } 1035 } 1036 1037 // If both streams aren't done then we have a differing number of 1038 // fields. 1039 if (!old_fs.done() || !new_fs.done()) { 1040 const char* action = old_fs.done() ? "added" : "deleted"; 1041 log_info(redefine, class, normalize) 1042 ("redefined class %s fields change error: some fields were %s.", 1043 the_class->external_name(), action); 1044 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 1045 } 1046 1047 // Do a parallel walk through the old and new methods. Detect 1048 // cases where they match (exist in both), have been added in 1049 // the new methods, or have been deleted (exist only in the 1050 // old methods). The class file parser places methods in order 1051 // by method name, but does not order overloaded methods by 1052 // signature. In order to determine what fate befell the methods, 1053 // this code places the overloaded new methods that have matching 1054 // old methods in the same order as the old methods and places 1055 // new overloaded methods at the end of overloaded methods of 1056 // that name. The code for this order normalization is adapted 1057 // from the algorithm used in InstanceKlass::find_method(). 1058 // Since we are swapping out of order entries as we find them, 1059 // we only have to search forward through the overloaded methods. 1060 // Methods which are added and have the same name as an existing 1061 // method (but different signature) will be put at the end of 1062 // the methods with that name, and the name mismatch code will 1063 // handle them. 1064 Array<Method*>* k_old_methods(the_class->methods()); 1065 Array<Method*>* k_new_methods(scratch_class->methods()); 1066 int n_old_methods = k_old_methods->length(); 1067 int n_new_methods = k_new_methods->length(); 1068 Thread* thread = Thread::current(); 1069 1070 int ni = 0; 1071 int oi = 0; 1072 while (true) { 1073 Method* k_old_method; 1074 Method* k_new_method; 1075 enum { matched, added, deleted, undetermined } method_was = undetermined; 1076 1077 if (oi >= n_old_methods) { 1078 if (ni >= n_new_methods) { 1079 break; // we've looked at everything, done 1080 } 1081 // New method at the end 1082 k_new_method = k_new_methods->at(ni); 1083 method_was = added; 1084 } else if (ni >= n_new_methods) { 1085 // Old method, at the end, is deleted 1086 k_old_method = k_old_methods->at(oi); 1087 method_was = deleted; 1088 } else { 1089 // There are more methods in both the old and new lists 1090 k_old_method = k_old_methods->at(oi); 1091 k_new_method = k_new_methods->at(ni); 1092 if (k_old_method->name() != k_new_method->name()) { 1093 // Methods are sorted by method name, so a mismatch means added 1094 // or deleted 1095 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) { 1096 method_was = added; 1097 } else { 1098 method_was = deleted; 1099 } 1100 } else if (k_old_method->signature() == k_new_method->signature()) { 1101 // Both the name and signature match 1102 method_was = matched; 1103 } else { 1104 // The name matches, but the signature doesn't, which means we have to 1105 // search forward through the new overloaded methods. 1106 int nj; // outside the loop for post-loop check 1107 for (nj = ni + 1; nj < n_new_methods; nj++) { 1108 Method* m = k_new_methods->at(nj); 1109 if (k_old_method->name() != m->name()) { 1110 // reached another method name so no more overloaded methods 1111 method_was = deleted; 1112 break; 1113 } 1114 if (k_old_method->signature() == m->signature()) { 1115 // found a match so swap the methods 1116 k_new_methods->at_put(ni, m); 1117 k_new_methods->at_put(nj, k_new_method); 1118 k_new_method = m; 1119 method_was = matched; 1120 break; 1121 } 1122 } 1123 1124 if (nj >= n_new_methods) { 1125 // reached the end without a match; so method was deleted 1126 method_was = deleted; 1127 } 1128 } 1129 } 1130 1131 switch (method_was) { 1132 case matched: 1133 // methods match, be sure modifiers do too 1134 old_flags = (jushort) k_old_method->access_flags().get_flags(); 1135 new_flags = (jushort) k_new_method->access_flags().get_flags(); 1136 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) { 1137 log_info(redefine, class, normalize) 1138 ("redefined class %s method %s modifiers error: modifiers changed from %d to %d", 1139 the_class->external_name(), k_old_method->name_and_sig_as_C_string(), old_flags, new_flags); 1140 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED; 1141 } 1142 { 1143 u2 new_num = k_new_method->method_idnum(); 1144 u2 old_num = k_old_method->method_idnum(); 1145 if (new_num != old_num) { 1146 Method* idnum_owner = scratch_class->method_with_idnum(old_num); 1147 if (idnum_owner != NULL) { 1148 // There is already a method assigned this idnum -- switch them 1149 // Take current and original idnum from the new_method 1150 idnum_owner->set_method_idnum(new_num); 1151 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum()); 1152 } 1153 // Take current and original idnum from the old_method 1154 k_new_method->set_method_idnum(old_num); 1155 k_new_method->set_orig_method_idnum(k_old_method->orig_method_idnum()); 1156 if (thread->has_pending_exception()) { 1157 return JVMTI_ERROR_OUT_OF_MEMORY; 1158 } 1159 } 1160 } 1161 log_trace(redefine, class, normalize) 1162 ("Method matched: new: %s [%d] == old: %s [%d]", 1163 k_new_method->name_and_sig_as_C_string(), ni, k_old_method->name_and_sig_as_C_string(), oi); 1164 // advance to next pair of methods 1165 ++oi; 1166 ++ni; 1167 break; 1168 case added: 1169 // method added, see if it is OK 1170 if (!can_add_or_delete(k_new_method)) { 1171 log_info(redefine, class, normalize) 1172 ("redefined class %s methods error: added method: %s [%d]", 1173 the_class->external_name(), k_new_method->name_and_sig_as_C_string(), ni); 1174 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED; 1175 } 1176 { 1177 u2 num = the_class->next_method_idnum(); 1178 if (num == ConstMethod::UNSET_IDNUM) { 1179 // cannot add any more methods 1180 log_info(redefine, class, normalize) 1181 ("redefined class %s methods error: can't create ID for new method %s [%d]", 1182 the_class->external_name(), k_new_method->name_and_sig_as_C_string(), ni); 1183 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED; 1184 } 1185 u2 new_num = k_new_method->method_idnum(); 1186 Method* idnum_owner = scratch_class->method_with_idnum(num); 1187 if (idnum_owner != NULL) { 1188 // There is already a method assigned this idnum -- switch them 1189 // Take current and original idnum from the new_method 1190 idnum_owner->set_method_idnum(new_num); 1191 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum()); 1192 } 1193 k_new_method->set_method_idnum(num); 1194 k_new_method->set_orig_method_idnum(num); 1195 if (thread->has_pending_exception()) { 1196 return JVMTI_ERROR_OUT_OF_MEMORY; 1197 } 1198 } 1199 log_trace(redefine, class, normalize) 1200 ("Method added: new: %s [%d]", k_new_method->name_and_sig_as_C_string(), ni); 1201 ++ni; // advance to next new method 1202 break; 1203 case deleted: 1204 // method deleted, see if it is OK 1205 if (!can_add_or_delete(k_old_method)) { 1206 log_info(redefine, class, normalize) 1207 ("redefined class %s methods error: deleted method %s [%d]", 1208 the_class->external_name(), k_old_method->name_and_sig_as_C_string(), oi); 1209 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED; 1210 } 1211 log_trace(redefine, class, normalize) 1212 ("Method deleted: old: %s [%d]", k_old_method->name_and_sig_as_C_string(), oi); 1213 ++oi; // advance to next old method 1214 break; 1215 default: 1216 ShouldNotReachHere(); 1217 } 1218 } 1219 1220 return JVMTI_ERROR_NONE; 1221 } 1222 1223 1224 // Find new constant pool index value for old constant pool index value 1225 // by seaching the index map. Returns zero (0) if there is no mapped 1226 // value for the old constant pool index. 1227 int VM_RedefineClasses::find_new_index(int old_index) { 1228 if (_index_map_count == 0) { 1229 // map is empty so nothing can be found 1230 return 0; 1231 } 1232 1233 if (old_index < 1 || old_index >= _index_map_p->length()) { 1234 // The old_index is out of range so it is not mapped. This should 1235 // not happen in regular constant pool merging use, but it can 1236 // happen if a corrupt annotation is processed. 1237 return 0; 1238 } 1239 1240 int value = _index_map_p->at(old_index); 1241 if (value == -1) { 1242 // the old_index is not mapped 1243 return 0; 1244 } 1245 1246 return value; 1247 } // end find_new_index() 1248 1249 1250 // Find new bootstrap specifier index value for old bootstrap specifier index 1251 // value by seaching the index map. Returns unused index (-1) if there is 1252 // no mapped value for the old bootstrap specifier index. 1253 int VM_RedefineClasses::find_new_operand_index(int old_index) { 1254 if (_operands_index_map_count == 0) { 1255 // map is empty so nothing can be found 1256 return -1; 1257 } 1258 1259 if (old_index == -1 || old_index >= _operands_index_map_p->length()) { 1260 // The old_index is out of range so it is not mapped. 1261 // This should not happen in regular constant pool merging use. 1262 return -1; 1263 } 1264 1265 int value = _operands_index_map_p->at(old_index); 1266 if (value == -1) { 1267 // the old_index is not mapped 1268 return -1; 1269 } 1270 1271 return value; 1272 } // end find_new_operand_index() 1273 1274 1275 // Returns true if the current mismatch is due to a resolved/unresolved 1276 // class pair. Otherwise, returns false. 1277 bool VM_RedefineClasses::is_unresolved_class_mismatch(const constantPoolHandle& cp1, 1278 int index1, const constantPoolHandle& cp2, int index2) { 1279 1280 jbyte t1 = cp1->tag_at(index1).value(); 1281 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) { 1282 return false; // wrong entry type; not our special case 1283 } 1284 1285 jbyte t2 = cp2->tag_at(index2).value(); 1286 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) { 1287 return false; // wrong entry type; not our special case 1288 } 1289 1290 if (t1 == t2) { 1291 return false; // not a mismatch; not our special case 1292 } 1293 1294 char *s1 = cp1->klass_name_at(index1)->as_C_string(); 1295 char *s2 = cp2->klass_name_at(index2)->as_C_string(); 1296 if (strcmp(s1, s2) != 0) { 1297 return false; // strings don't match; not our special case 1298 } 1299 1300 return true; // made it through the gauntlet; this is our special case 1301 } // end is_unresolved_class_mismatch() 1302 1303 1304 // The bug 6214132 caused the verification to fail. 1305 // 1. What's done in RedefineClasses() before verification: 1306 // a) A reference to the class being redefined (_the_class) and a 1307 // reference to new version of the class (_scratch_class) are 1308 // saved here for use during the bytecode verification phase of 1309 // RedefineClasses. 1310 // b) The _java_mirror field from _the_class is copied to the 1311 // _java_mirror field in _scratch_class. This means that a jclass 1312 // returned for _the_class or _scratch_class will refer to the 1313 // same Java mirror. The verifier will see the "one true mirror" 1314 // for the class being verified. 1315 // 2. See comments in JvmtiThreadState for what is done during verification. 1316 1317 class RedefineVerifyMark : public StackObj { 1318 private: 1319 JvmtiThreadState* _state; 1320 Klass* _scratch_class; 1321 Handle _scratch_mirror; 1322 1323 public: 1324 1325 RedefineVerifyMark(Klass* the_class, Klass* scratch_class, 1326 JvmtiThreadState* state) : _state(state), _scratch_class(scratch_class) 1327 { 1328 _state->set_class_versions_map(the_class, scratch_class); 1329 _scratch_mirror = Handle(_state->get_thread(), _scratch_class->java_mirror()); 1330 _scratch_class->replace_java_mirror(the_class->java_mirror()); 1331 } 1332 1333 ~RedefineVerifyMark() { 1334 // Restore the scratch class's mirror, so when scratch_class is removed 1335 // the correct mirror pointing to it can be cleared. 1336 _scratch_class->replace_java_mirror(_scratch_mirror()); 1337 _state->clear_class_versions_map(); 1338 } 1339 }; 1340 1341 1342 jvmtiError VM_RedefineClasses::load_new_class_versions() { 1343 1344 // For consistency allocate memory using os::malloc wrapper. 1345 _scratch_classes = (InstanceKlass**) 1346 os::malloc(sizeof(InstanceKlass*) * _class_count, mtClass); 1347 if (_scratch_classes == NULL) { 1348 return JVMTI_ERROR_OUT_OF_MEMORY; 1349 } 1350 // Zero initialize the _scratch_classes array. 1351 for (int i = 0; i < _class_count; i++) { 1352 _scratch_classes[i] = NULL; 1353 } 1354 1355 JavaThread* current = JavaThread::current(); 1356 ResourceMark rm(current); 1357 1358 JvmtiThreadState *state = JvmtiThreadState::state_for(current); 1359 // state can only be NULL if the current thread is exiting which 1360 // should not happen since we're trying to do a RedefineClasses 1361 guarantee(state != NULL, "exiting thread calling load_new_class_versions"); 1362 for (int i = 0; i < _class_count; i++) { 1363 // Create HandleMark so that any handles created while loading new class 1364 // versions are deleted. Constant pools are deallocated while merging 1365 // constant pools 1366 HandleMark hm(current); 1367 InstanceKlass* the_class = get_ik(_class_defs[i].klass); 1368 1369 log_debug(redefine, class, load) 1370 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)", 1371 the_class->external_name(), _class_load_kind, os::available_memory() >> 10); 1372 1373 ClassFileStream st((u1*)_class_defs[i].class_bytes, 1374 _class_defs[i].class_byte_count, 1375 "__VM_RedefineClasses__", 1376 ClassFileStream::verify); 1377 1378 // Set redefined class handle in JvmtiThreadState class. 1379 // This redefined class is sent to agent event handler for class file 1380 // load hook event. 1381 state->set_class_being_redefined(the_class, _class_load_kind); 1382 1383 JavaThread* THREAD = current; // For exception macros. 1384 ExceptionMark em(THREAD); 1385 Handle protection_domain(THREAD, the_class->protection_domain()); 1386 ClassLoadInfo cl_info(protection_domain); 1387 // Parse and create a class from the bytes, but this class isn't added 1388 // to the dictionary, so do not call resolve_from_stream. 1389 InstanceKlass* scratch_class = KlassFactory::create_from_stream(&st, 1390 the_class->name(), 1391 the_class->class_loader_data(), 1392 cl_info, 1393 THREAD); 1394 1395 // Clear class_being_redefined just to be sure. 1396 state->clear_class_being_redefined(); 1397 1398 // TODO: if this is retransform, and nothing changed we can skip it 1399 1400 // Need to clean up allocated InstanceKlass if there's an error so assign 1401 // the result here. Caller deallocates all the scratch classes in case of 1402 // an error. 1403 _scratch_classes[i] = scratch_class; 1404 1405 if (HAS_PENDING_EXCEPTION) { 1406 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1407 log_info(redefine, class, load, exceptions)("create_from_stream exception: '%s'", ex_name->as_C_string()); 1408 CLEAR_PENDING_EXCEPTION; 1409 1410 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) { 1411 return JVMTI_ERROR_UNSUPPORTED_VERSION; 1412 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) { 1413 return JVMTI_ERROR_INVALID_CLASS_FORMAT; 1414 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) { 1415 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION; 1416 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) { 1417 // The message will be "XXX (wrong name: YYY)" 1418 return JVMTI_ERROR_NAMES_DONT_MATCH; 1419 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1420 return JVMTI_ERROR_OUT_OF_MEMORY; 1421 } else { // Just in case more exceptions can be thrown.. 1422 return JVMTI_ERROR_FAILS_VERIFICATION; 1423 } 1424 } 1425 1426 // Ensure class is linked before redefine 1427 if (!the_class->is_linked()) { 1428 the_class->link_class(THREAD); 1429 if (HAS_PENDING_EXCEPTION) { 1430 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1431 oop message = java_lang_Throwable::message(PENDING_EXCEPTION); 1432 if (message != NULL) { 1433 char* ex_msg = java_lang_String::as_utf8_string(message); 1434 log_info(redefine, class, load, exceptions)("link_class exception: '%s %s'", 1435 ex_name->as_C_string(), ex_msg); 1436 } else { 1437 log_info(redefine, class, load, exceptions)("link_class exception: '%s'", 1438 ex_name->as_C_string()); 1439 } 1440 CLEAR_PENDING_EXCEPTION; 1441 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1442 return JVMTI_ERROR_OUT_OF_MEMORY; 1443 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) { 1444 return JVMTI_ERROR_INVALID_CLASS; 1445 } else { 1446 return JVMTI_ERROR_INTERNAL; 1447 } 1448 } 1449 } 1450 1451 // Do the validity checks in compare_and_normalize_class_versions() 1452 // before verifying the byte codes. By doing these checks first, we 1453 // limit the number of functions that require redirection from 1454 // the_class to scratch_class. In particular, we don't have to 1455 // modify JNI GetSuperclass() and thus won't change its performance. 1456 jvmtiError res = compare_and_normalize_class_versions(the_class, 1457 scratch_class); 1458 if (res != JVMTI_ERROR_NONE) { 1459 return res; 1460 } 1461 1462 // verify what the caller passed us 1463 { 1464 // The bug 6214132 caused the verification to fail. 1465 // Information about the_class and scratch_class is temporarily 1466 // recorded into jvmtiThreadState. This data is used to redirect 1467 // the_class to scratch_class in the JVM_* functions called by the 1468 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed 1469 // description. 1470 RedefineVerifyMark rvm(the_class, scratch_class, state); 1471 Verifier::verify(scratch_class, true, THREAD); 1472 } 1473 1474 if (HAS_PENDING_EXCEPTION) { 1475 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1476 log_info(redefine, class, load, exceptions)("verify_byte_codes exception: '%s'", ex_name->as_C_string()); 1477 CLEAR_PENDING_EXCEPTION; 1478 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1479 return JVMTI_ERROR_OUT_OF_MEMORY; 1480 } else { 1481 // tell the caller the bytecodes are bad 1482 return JVMTI_ERROR_FAILS_VERIFICATION; 1483 } 1484 } 1485 1486 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD); 1487 if (HAS_PENDING_EXCEPTION) { 1488 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1489 log_info(redefine, class, load, exceptions)("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string()); 1490 CLEAR_PENDING_EXCEPTION; 1491 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1492 return JVMTI_ERROR_OUT_OF_MEMORY; 1493 } else { 1494 return JVMTI_ERROR_INTERNAL; 1495 } 1496 } 1497 1498 #ifdef ASSERT 1499 { 1500 // verify what we have done during constant pool merging 1501 { 1502 RedefineVerifyMark rvm(the_class, scratch_class, state); 1503 Verifier::verify(scratch_class, true, THREAD); 1504 } 1505 1506 if (HAS_PENDING_EXCEPTION) { 1507 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1508 log_info(redefine, class, load, exceptions) 1509 ("verify_byte_codes post merge-CP exception: '%s'", ex_name->as_C_string()); 1510 CLEAR_PENDING_EXCEPTION; 1511 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1512 return JVMTI_ERROR_OUT_OF_MEMORY; 1513 } else { 1514 // tell the caller that constant pool merging screwed up 1515 return JVMTI_ERROR_INTERNAL; 1516 } 1517 } 1518 } 1519 #endif // ASSERT 1520 1521 Rewriter::rewrite(scratch_class, THREAD); 1522 if (!HAS_PENDING_EXCEPTION) { 1523 scratch_class->link_methods(THREAD); 1524 } 1525 if (HAS_PENDING_EXCEPTION) { 1526 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1527 log_info(redefine, class, load, exceptions) 1528 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string()); 1529 CLEAR_PENDING_EXCEPTION; 1530 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1531 return JVMTI_ERROR_OUT_OF_MEMORY; 1532 } else { 1533 return JVMTI_ERROR_INTERNAL; 1534 } 1535 } 1536 1537 log_debug(redefine, class, load) 1538 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)", the_class->external_name(), os::available_memory() >> 10); 1539 } 1540 1541 return JVMTI_ERROR_NONE; 1542 } 1543 1544 1545 // Map old_index to new_index as needed. scratch_cp is only needed 1546 // for log calls. 1547 void VM_RedefineClasses::map_index(const constantPoolHandle& scratch_cp, 1548 int old_index, int new_index) { 1549 if (find_new_index(old_index) != 0) { 1550 // old_index is already mapped 1551 return; 1552 } 1553 1554 if (old_index == new_index) { 1555 // no mapping is needed 1556 return; 1557 } 1558 1559 _index_map_p->at_put(old_index, new_index); 1560 _index_map_count++; 1561 1562 log_trace(redefine, class, constantpool) 1563 ("mapped tag %d at index %d to %d", scratch_cp->tag_at(old_index).value(), old_index, new_index); 1564 } // end map_index() 1565 1566 1567 // Map old_index to new_index as needed. 1568 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) { 1569 if (find_new_operand_index(old_index) != -1) { 1570 // old_index is already mapped 1571 return; 1572 } 1573 1574 if (old_index == new_index) { 1575 // no mapping is needed 1576 return; 1577 } 1578 1579 _operands_index_map_p->at_put(old_index, new_index); 1580 _operands_index_map_count++; 1581 1582 log_trace(redefine, class, constantpool)("mapped bootstrap specifier at index %d to %d", old_index, new_index); 1583 } // end map_index() 1584 1585 1586 // Merge old_cp and scratch_cp and return the results of the merge via 1587 // merge_cp_p. The number of entries in *merge_cp_p is returned via 1588 // merge_cp_length_p. The entries in old_cp occupy the same locations 1589 // in *merge_cp_p. Also creates a map of indices from entries in 1590 // scratch_cp to the corresponding entry in *merge_cp_p. Index map 1591 // entries are only created for entries in scratch_cp that occupy a 1592 // different location in *merged_cp_p. 1593 bool VM_RedefineClasses::merge_constant_pools(const constantPoolHandle& old_cp, 1594 const constantPoolHandle& scratch_cp, constantPoolHandle *merge_cp_p, 1595 int *merge_cp_length_p, TRAPS) { 1596 1597 if (merge_cp_p == NULL) { 1598 assert(false, "caller must provide scratch constantPool"); 1599 return false; // robustness 1600 } 1601 if (merge_cp_length_p == NULL) { 1602 assert(false, "caller must provide scratch CP length"); 1603 return false; // robustness 1604 } 1605 // Worst case we need old_cp->length() + scratch_cp()->length(), 1606 // but the caller might be smart so make sure we have at least 1607 // the minimum. 1608 if ((*merge_cp_p)->length() < old_cp->length()) { 1609 assert(false, "merge area too small"); 1610 return false; // robustness 1611 } 1612 1613 log_info(redefine, class, constantpool)("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(), scratch_cp->length()); 1614 1615 { 1616 // Pass 0: 1617 // The old_cp is copied to *merge_cp_p; this means that any code 1618 // using old_cp does not have to change. This work looks like a 1619 // perfect fit for ConstantPool*::copy_cp_to(), but we need to 1620 // handle one special case: 1621 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass 1622 // This will make verification happy. 1623 1624 int old_i; // index into old_cp 1625 1626 // index zero (0) is not used in constantPools 1627 for (old_i = 1; old_i < old_cp->length(); old_i++) { 1628 // leave debugging crumb 1629 jbyte old_tag = old_cp->tag_at(old_i).value(); 1630 switch (old_tag) { 1631 case JVM_CONSTANT_Class: 1632 case JVM_CONSTANT_UnresolvedClass: 1633 // revert the copy to JVM_CONSTANT_UnresolvedClass 1634 // May be resolving while calling this so do the same for 1635 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition) 1636 (*merge_cp_p)->temp_unresolved_klass_at_put(old_i, 1637 old_cp->klass_name_index_at(old_i)); 1638 break; 1639 1640 case JVM_CONSTANT_Double: 1641 case JVM_CONSTANT_Long: 1642 // just copy the entry to *merge_cp_p, but double and long take 1643 // two constant pool entries 1644 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i); 1645 old_i++; 1646 break; 1647 1648 default: 1649 // just copy the entry to *merge_cp_p 1650 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i); 1651 break; 1652 } 1653 } // end for each old_cp entry 1654 1655 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_false); 1656 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_false); 1657 1658 // We don't need to sanity check that *merge_cp_length_p is within 1659 // *merge_cp_p bounds since we have the minimum on-entry check above. 1660 (*merge_cp_length_p) = old_i; 1661 } 1662 1663 // merge_cp_len should be the same as old_cp->length() at this point 1664 // so this trace message is really a "warm-and-breathing" message. 1665 log_debug(redefine, class, constantpool)("after pass 0: merge_cp_len=%d", *merge_cp_length_p); 1666 1667 int scratch_i; // index into scratch_cp 1668 { 1669 // Pass 1a: 1670 // Compare scratch_cp entries to the old_cp entries that we have 1671 // already copied to *merge_cp_p. In this pass, we are eliminating 1672 // exact duplicates (matching entry at same index) so we only 1673 // compare entries in the common indice range. 1674 int increment = 1; 1675 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length()); 1676 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) { 1677 switch (scratch_cp->tag_at(scratch_i).value()) { 1678 case JVM_CONSTANT_Double: 1679 case JVM_CONSTANT_Long: 1680 // double and long take two constant pool entries 1681 increment = 2; 1682 break; 1683 1684 default: 1685 increment = 1; 1686 break; 1687 } 1688 1689 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p, scratch_i); 1690 if (match) { 1691 // found a match at the same index so nothing more to do 1692 continue; 1693 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i, 1694 *merge_cp_p, scratch_i)) { 1695 // The mismatch in compare_entry_to() above is because of a 1696 // resolved versus unresolved class entry at the same index 1697 // with the same string value. Since Pass 0 reverted any 1698 // class entries to unresolved class entries in *merge_cp_p, 1699 // we go with the unresolved class entry. 1700 continue; 1701 } 1702 1703 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p); 1704 if (found_i != 0) { 1705 guarantee(found_i != scratch_i, 1706 "compare_entry_to() and find_matching_entry() do not agree"); 1707 1708 // Found a matching entry somewhere else in *merge_cp_p so 1709 // just need a mapping entry. 1710 map_index(scratch_cp, scratch_i, found_i); 1711 continue; 1712 } 1713 1714 // The find_matching_entry() call above could fail to find a match 1715 // due to a resolved versus unresolved class or string entry situation 1716 // like we solved above with the is_unresolved_*_mismatch() calls. 1717 // However, we would have to call is_unresolved_*_mismatch() over 1718 // all of *merge_cp_p (potentially) and that doesn't seem to be 1719 // worth the time. 1720 1721 // No match found so we have to append this entry and any unique 1722 // referenced entries to *merge_cp_p. 1723 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p); 1724 } 1725 } 1726 1727 log_debug(redefine, class, constantpool) 1728 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", 1729 *merge_cp_length_p, scratch_i, _index_map_count); 1730 1731 if (scratch_i < scratch_cp->length()) { 1732 // Pass 1b: 1733 // old_cp is smaller than scratch_cp so there are entries in 1734 // scratch_cp that we have not yet processed. We take care of 1735 // those now. 1736 int increment = 1; 1737 for (; scratch_i < scratch_cp->length(); scratch_i += increment) { 1738 switch (scratch_cp->tag_at(scratch_i).value()) { 1739 case JVM_CONSTANT_Double: 1740 case JVM_CONSTANT_Long: 1741 // double and long take two constant pool entries 1742 increment = 2; 1743 break; 1744 1745 default: 1746 increment = 1; 1747 break; 1748 } 1749 1750 int found_i = 1751 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p); 1752 if (found_i != 0) { 1753 // Found a matching entry somewhere else in *merge_cp_p so 1754 // just need a mapping entry. 1755 map_index(scratch_cp, scratch_i, found_i); 1756 continue; 1757 } 1758 1759 // No match found so we have to append this entry and any unique 1760 // referenced entries to *merge_cp_p. 1761 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p); 1762 } 1763 1764 log_debug(redefine, class, constantpool) 1765 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", 1766 *merge_cp_length_p, scratch_i, _index_map_count); 1767 } 1768 finalize_operands_merge(*merge_cp_p, CHECK_false); 1769 1770 return true; 1771 } // end merge_constant_pools() 1772 1773 1774 // Scoped object to clean up the constant pool(s) created for merging 1775 class MergeCPCleaner { 1776 ClassLoaderData* _loader_data; 1777 ConstantPool* _cp; 1778 ConstantPool* _scratch_cp; 1779 public: 1780 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) : 1781 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {} 1782 ~MergeCPCleaner() { 1783 _loader_data->add_to_deallocate_list(_cp); 1784 if (_scratch_cp != NULL) { 1785 _loader_data->add_to_deallocate_list(_scratch_cp); 1786 } 1787 } 1788 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; } 1789 }; 1790 1791 // Merge constant pools between the_class and scratch_class and 1792 // potentially rewrite bytecodes in scratch_class to use the merged 1793 // constant pool. 1794 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite( 1795 InstanceKlass* the_class, InstanceKlass* scratch_class, 1796 TRAPS) { 1797 // worst case merged constant pool length is old and new combined 1798 int merge_cp_length = the_class->constants()->length() 1799 + scratch_class->constants()->length(); 1800 1801 // Constant pools are not easily reused so we allocate a new one 1802 // each time. 1803 // merge_cp is created unsafe for concurrent GC processing. It 1804 // should be marked safe before discarding it. Even though 1805 // garbage, if it crosses a card boundary, it may be scanned 1806 // in order to find the start of the first complete object on the card. 1807 ClassLoaderData* loader_data = the_class->class_loader_data(); 1808 ConstantPool* merge_cp_oop = 1809 ConstantPool::allocate(loader_data, 1810 merge_cp_length, 1811 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1812 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop); 1813 1814 HandleMark hm(THREAD); // make sure handles are cleared before 1815 // MergeCPCleaner clears out merge_cp_oop 1816 constantPoolHandle merge_cp(THREAD, merge_cp_oop); 1817 1818 // Get constants() from the old class because it could have been rewritten 1819 // while we were at a safepoint allocating a new constant pool. 1820 constantPoolHandle old_cp(THREAD, the_class->constants()); 1821 constantPoolHandle scratch_cp(THREAD, scratch_class->constants()); 1822 1823 // If the length changed, the class was redefined out from under us. Return 1824 // an error. 1825 if (merge_cp_length != the_class->constants()->length() 1826 + scratch_class->constants()->length()) { 1827 return JVMTI_ERROR_INTERNAL; 1828 } 1829 1830 // Update the version number of the constant pools (may keep scratch_cp) 1831 merge_cp->increment_and_save_version(old_cp->version()); 1832 scratch_cp->increment_and_save_version(old_cp->version()); 1833 1834 ResourceMark rm(THREAD); 1835 _index_map_count = 0; 1836 _index_map_p = new intArray(scratch_cp->length(), scratch_cp->length(), -1); 1837 1838 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands()); 1839 _operands_index_map_count = 0; 1840 int operands_index_map_len = ConstantPool::operand_array_length(scratch_cp->operands()); 1841 _operands_index_map_p = new intArray(operands_index_map_len, operands_index_map_len, -1); 1842 1843 // reference to the cp holder is needed for copy_operands() 1844 merge_cp->set_pool_holder(scratch_class); 1845 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp, 1846 &merge_cp_length, THREAD); 1847 merge_cp->set_pool_holder(NULL); 1848 1849 if (!result) { 1850 // The merge can fail due to memory allocation failure or due 1851 // to robustness checks. 1852 return JVMTI_ERROR_INTERNAL; 1853 } 1854 1855 // Set dynamic constants attribute from the original CP. 1856 if (old_cp->has_dynamic_constant()) { 1857 scratch_cp->set_has_dynamic_constant(); 1858 } 1859 // Copy attributes from scratch_cp to merge_cp 1860 merge_cp->copy_fields(scratch_cp()); 1861 1862 log_info(redefine, class, constantpool)("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count); 1863 1864 if (_index_map_count == 0) { 1865 // there is nothing to map between the new and merged constant pools 1866 1867 if (old_cp->length() == scratch_cp->length()) { 1868 // The old and new constant pools are the same length and the 1869 // index map is empty. This means that the three constant pools 1870 // are equivalent (but not the same). Unfortunately, the new 1871 // constant pool has not gone through link resolution nor have 1872 // the new class bytecodes gone through constant pool cache 1873 // rewriting so we can't use the old constant pool with the new 1874 // class. 1875 1876 // toss the merged constant pool at return 1877 } else if (old_cp->length() < scratch_cp->length()) { 1878 // The old constant pool has fewer entries than the new constant 1879 // pool and the index map is empty. This means the new constant 1880 // pool is a superset of the old constant pool. However, the old 1881 // class bytecodes have already gone through constant pool cache 1882 // rewriting so we can't use the new constant pool with the old 1883 // class. 1884 1885 // toss the merged constant pool at return 1886 } else { 1887 // The old constant pool has more entries than the new constant 1888 // pool and the index map is empty. This means that both the old 1889 // and merged constant pools are supersets of the new constant 1890 // pool. 1891 1892 // Replace the new constant pool with a shrunken copy of the 1893 // merged constant pool 1894 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, 1895 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1896 // The new constant pool replaces scratch_cp so have cleaner clean it up. 1897 // It can't be cleaned up while there are handles to it. 1898 cp_cleaner.add_scratch_cp(scratch_cp()); 1899 } 1900 } else { 1901 if (log_is_enabled(Trace, redefine, class, constantpool)) { 1902 // don't want to loop unless we are tracing 1903 int count = 0; 1904 for (int i = 1; i < _index_map_p->length(); i++) { 1905 int value = _index_map_p->at(i); 1906 1907 if (value != -1) { 1908 log_trace(redefine, class, constantpool)("index_map[%d]: old=%d new=%d", count, i, value); 1909 count++; 1910 } 1911 } 1912 } 1913 1914 // We have entries mapped between the new and merged constant pools 1915 // so we have to rewrite some constant pool references. 1916 if (!rewrite_cp_refs(scratch_class)) { 1917 return JVMTI_ERROR_INTERNAL; 1918 } 1919 1920 // Replace the new constant pool with a shrunken copy of the 1921 // merged constant pool so now the rewritten bytecodes have 1922 // valid references; the previous new constant pool will get 1923 // GCed. 1924 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, 1925 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1926 // The new constant pool replaces scratch_cp so have cleaner clean it up. 1927 // It can't be cleaned up while there are handles to it. 1928 cp_cleaner.add_scratch_cp(scratch_cp()); 1929 } 1930 1931 return JVMTI_ERROR_NONE; 1932 } // end merge_cp_and_rewrite() 1933 1934 1935 // Rewrite constant pool references in klass scratch_class. 1936 bool VM_RedefineClasses::rewrite_cp_refs(InstanceKlass* scratch_class) { 1937 1938 // rewrite constant pool references in the nest attributes: 1939 if (!rewrite_cp_refs_in_nest_attributes(scratch_class)) { 1940 // propagate failure back to caller 1941 return false; 1942 } 1943 1944 // rewrite constant pool references in the Record attribute: 1945 if (!rewrite_cp_refs_in_record_attribute(scratch_class)) { 1946 // propagate failure back to caller 1947 return false; 1948 } 1949 1950 // rewrite constant pool references in the PermittedSubclasses attribute: 1951 if (!rewrite_cp_refs_in_permitted_subclasses_attribute(scratch_class)) { 1952 // propagate failure back to caller 1953 return false; 1954 } 1955 1956 // rewrite constant pool references in the methods: 1957 if (!rewrite_cp_refs_in_methods(scratch_class)) { 1958 // propagate failure back to caller 1959 return false; 1960 } 1961 1962 // rewrite constant pool references in the class_annotations: 1963 if (!rewrite_cp_refs_in_class_annotations(scratch_class)) { 1964 // propagate failure back to caller 1965 return false; 1966 } 1967 1968 // rewrite constant pool references in the fields_annotations: 1969 if (!rewrite_cp_refs_in_fields_annotations(scratch_class)) { 1970 // propagate failure back to caller 1971 return false; 1972 } 1973 1974 // rewrite constant pool references in the methods_annotations: 1975 if (!rewrite_cp_refs_in_methods_annotations(scratch_class)) { 1976 // propagate failure back to caller 1977 return false; 1978 } 1979 1980 // rewrite constant pool references in the methods_parameter_annotations: 1981 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class)) { 1982 // propagate failure back to caller 1983 return false; 1984 } 1985 1986 // rewrite constant pool references in the methods_default_annotations: 1987 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class)) { 1988 // propagate failure back to caller 1989 return false; 1990 } 1991 1992 // rewrite constant pool references in the class_type_annotations: 1993 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class)) { 1994 // propagate failure back to caller 1995 return false; 1996 } 1997 1998 // rewrite constant pool references in the fields_type_annotations: 1999 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class)) { 2000 // propagate failure back to caller 2001 return false; 2002 } 2003 2004 // rewrite constant pool references in the methods_type_annotations: 2005 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class)) { 2006 // propagate failure back to caller 2007 return false; 2008 } 2009 2010 // There can be type annotations in the Code part of a method_info attribute. 2011 // These annotations are not accessible, even by reflection. 2012 // Currently they are not even parsed by the ClassFileParser. 2013 // If runtime access is added they will also need to be rewritten. 2014 2015 // rewrite source file name index: 2016 u2 source_file_name_idx = scratch_class->source_file_name_index(); 2017 if (source_file_name_idx != 0) { 2018 u2 new_source_file_name_idx = find_new_index(source_file_name_idx); 2019 if (new_source_file_name_idx != 0) { 2020 scratch_class->set_source_file_name_index(new_source_file_name_idx); 2021 } 2022 } 2023 2024 // rewrite class generic signature index: 2025 u2 generic_signature_index = scratch_class->generic_signature_index(); 2026 if (generic_signature_index != 0) { 2027 u2 new_generic_signature_index = find_new_index(generic_signature_index); 2028 if (new_generic_signature_index != 0) { 2029 scratch_class->set_generic_signature_index(new_generic_signature_index); 2030 } 2031 } 2032 2033 return true; 2034 } // end rewrite_cp_refs() 2035 2036 // Rewrite constant pool references in the NestHost and NestMembers attributes. 2037 bool VM_RedefineClasses::rewrite_cp_refs_in_nest_attributes( 2038 InstanceKlass* scratch_class) { 2039 2040 u2 cp_index = scratch_class->nest_host_index(); 2041 if (cp_index != 0) { 2042 scratch_class->set_nest_host_index(find_new_index(cp_index)); 2043 } 2044 Array<u2>* nest_members = scratch_class->nest_members(); 2045 for (int i = 0; i < nest_members->length(); i++) { 2046 u2 cp_index = nest_members->at(i); 2047 nest_members->at_put(i, find_new_index(cp_index)); 2048 } 2049 return true; 2050 } 2051 2052 // Rewrite constant pool references in the Record attribute. 2053 bool VM_RedefineClasses::rewrite_cp_refs_in_record_attribute(InstanceKlass* scratch_class) { 2054 Array<RecordComponent*>* components = scratch_class->record_components(); 2055 if (components != NULL) { 2056 for (int i = 0; i < components->length(); i++) { 2057 RecordComponent* component = components->at(i); 2058 u2 cp_index = component->name_index(); 2059 component->set_name_index(find_new_index(cp_index)); 2060 cp_index = component->descriptor_index(); 2061 component->set_descriptor_index(find_new_index(cp_index)); 2062 cp_index = component->generic_signature_index(); 2063 if (cp_index != 0) { 2064 component->set_generic_signature_index(find_new_index(cp_index)); 2065 } 2066 2067 AnnotationArray* annotations = component->annotations(); 2068 if (annotations != NULL && annotations->length() != 0) { 2069 int byte_i = 0; // byte index into annotations 2070 if (!rewrite_cp_refs_in_annotations_typeArray(annotations, byte_i)) { 2071 log_debug(redefine, class, annotation)("bad record_component_annotations at %d", i); 2072 // propagate failure back to caller 2073 return false; 2074 } 2075 } 2076 2077 AnnotationArray* type_annotations = component->type_annotations(); 2078 if (type_annotations != NULL && type_annotations->length() != 0) { 2079 int byte_i = 0; // byte index into annotations 2080 if (!rewrite_cp_refs_in_annotations_typeArray(type_annotations, byte_i)) { 2081 log_debug(redefine, class, annotation)("bad record_component_type_annotations at %d", i); 2082 // propagate failure back to caller 2083 return false; 2084 } 2085 } 2086 } 2087 } 2088 return true; 2089 } 2090 2091 // Rewrite constant pool references in the PermittedSubclasses attribute. 2092 bool VM_RedefineClasses::rewrite_cp_refs_in_permitted_subclasses_attribute( 2093 InstanceKlass* scratch_class) { 2094 2095 Array<u2>* permitted_subclasses = scratch_class->permitted_subclasses(); 2096 assert(permitted_subclasses != NULL, "unexpected null permitted_subclasses"); 2097 for (int i = 0; i < permitted_subclasses->length(); i++) { 2098 u2 cp_index = permitted_subclasses->at(i); 2099 permitted_subclasses->at_put(i, find_new_index(cp_index)); 2100 } 2101 return true; 2102 } 2103 2104 // Rewrite constant pool references in the methods. 2105 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(InstanceKlass* scratch_class) { 2106 2107 Array<Method*>* methods = scratch_class->methods(); 2108 2109 if (methods == NULL || methods->length() == 0) { 2110 // no methods so nothing to do 2111 return true; 2112 } 2113 2114 JavaThread* THREAD = JavaThread::current(); // For exception macros. 2115 ExceptionMark em(THREAD); 2116 2117 // rewrite constant pool references in the methods: 2118 for (int i = methods->length() - 1; i >= 0; i--) { 2119 methodHandle method(THREAD, methods->at(i)); 2120 methodHandle new_method; 2121 rewrite_cp_refs_in_method(method, &new_method, THREAD); 2122 if (!new_method.is_null()) { 2123 // the method has been replaced so save the new method version 2124 // even in the case of an exception. original method is on the 2125 // deallocation list. 2126 methods->at_put(i, new_method()); 2127 } 2128 if (HAS_PENDING_EXCEPTION) { 2129 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 2130 log_info(redefine, class, load, exceptions)("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string()); 2131 // Need to clear pending exception here as the super caller sets 2132 // the JVMTI_ERROR_INTERNAL if the returned value is false. 2133 CLEAR_PENDING_EXCEPTION; 2134 return false; 2135 } 2136 } 2137 2138 return true; 2139 } 2140 2141 2142 // Rewrite constant pool references in the specific method. This code 2143 // was adapted from Rewriter::rewrite_method(). 2144 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method, 2145 methodHandle *new_method_p, TRAPS) { 2146 2147 *new_method_p = methodHandle(); // default is no new method 2148 2149 // We cache a pointer to the bytecodes here in code_base. If GC 2150 // moves the Method*, then the bytecodes will also move which 2151 // will likely cause a crash. We create a NoSafepointVerifier 2152 // object to detect whether we pass a possible safepoint in this 2153 // code block. 2154 NoSafepointVerifier nsv; 2155 2156 // Bytecodes and their length 2157 address code_base = method->code_base(); 2158 int code_length = method->code_size(); 2159 2160 int bc_length; 2161 for (int bci = 0; bci < code_length; bci += bc_length) { 2162 address bcp = code_base + bci; 2163 Bytecodes::Code c = (Bytecodes::Code)(*bcp); 2164 2165 bc_length = Bytecodes::length_for(c); 2166 if (bc_length == 0) { 2167 // More complicated bytecodes report a length of zero so 2168 // we have to try again a slightly different way. 2169 bc_length = Bytecodes::length_at(method(), bcp); 2170 } 2171 2172 assert(bc_length != 0, "impossible bytecode length"); 2173 2174 switch (c) { 2175 case Bytecodes::_ldc: 2176 { 2177 int cp_index = *(bcp + 1); 2178 int new_index = find_new_index(cp_index); 2179 2180 if (StressLdcRewrite && new_index == 0) { 2181 // If we are stressing ldc -> ldc_w rewriting, then we 2182 // always need a new_index value. 2183 new_index = cp_index; 2184 } 2185 if (new_index != 0) { 2186 // the original index is mapped so we have more work to do 2187 if (!StressLdcRewrite && new_index <= max_jubyte) { 2188 // The new value can still use ldc instead of ldc_w 2189 // unless we are trying to stress ldc -> ldc_w rewriting 2190 log_trace(redefine, class, constantpool) 2191 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index); 2192 *(bcp + 1) = new_index; 2193 } else { 2194 log_trace(redefine, class, constantpool) 2195 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index); 2196 // the new value needs ldc_w instead of ldc 2197 u_char inst_buffer[4]; // max instruction size is 4 bytes 2198 bcp = (address)inst_buffer; 2199 // construct new instruction sequence 2200 *bcp = Bytecodes::_ldc_w; 2201 bcp++; 2202 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w. 2203 // See comment below for difference between put_Java_u2() 2204 // and put_native_u2(). 2205 Bytes::put_Java_u2(bcp, new_index); 2206 2207 Relocator rc(method, NULL /* no RelocatorListener needed */); 2208 methodHandle m; 2209 { 2210 PauseNoSafepointVerifier pnsv(&nsv); 2211 2212 // ldc is 2 bytes and ldc_w is 3 bytes 2213 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK); 2214 } 2215 2216 // return the new method so that the caller can update 2217 // the containing class 2218 *new_method_p = method = m; 2219 // switch our bytecode processing loop from the old method 2220 // to the new method 2221 code_base = method->code_base(); 2222 code_length = method->code_size(); 2223 bcp = code_base + bci; 2224 c = (Bytecodes::Code)(*bcp); 2225 bc_length = Bytecodes::length_for(c); 2226 assert(bc_length != 0, "sanity check"); 2227 } // end we need ldc_w instead of ldc 2228 } // end if there is a mapped index 2229 } break; 2230 2231 // these bytecodes have a two-byte constant pool index 2232 case Bytecodes::_anewarray : // fall through 2233 case Bytecodes::_checkcast : // fall through 2234 case Bytecodes::_getfield : // fall through 2235 case Bytecodes::_getstatic : // fall through 2236 case Bytecodes::_instanceof : // fall through 2237 case Bytecodes::_invokedynamic : // fall through 2238 case Bytecodes::_invokeinterface: // fall through 2239 case Bytecodes::_invokespecial : // fall through 2240 case Bytecodes::_invokestatic : // fall through 2241 case Bytecodes::_invokevirtual : // fall through 2242 case Bytecodes::_ldc_w : // fall through 2243 case Bytecodes::_ldc2_w : // fall through 2244 case Bytecodes::_multianewarray : // fall through 2245 case Bytecodes::_new : // fall through 2246 case Bytecodes::_putfield : // fall through 2247 case Bytecodes::_putstatic : 2248 { 2249 address p = bcp + 1; 2250 int cp_index = Bytes::get_Java_u2(p); 2251 int new_index = find_new_index(cp_index); 2252 if (new_index != 0) { 2253 // the original index is mapped so update w/ new value 2254 log_trace(redefine, class, constantpool) 2255 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),p2i(bcp), cp_index, new_index); 2256 // Rewriter::rewrite_method() uses put_native_u2() in this 2257 // situation because it is reusing the constant pool index 2258 // location for a native index into the ConstantPoolCache. 2259 // Since we are updating the constant pool index prior to 2260 // verification and ConstantPoolCache initialization, we 2261 // need to keep the new index in Java byte order. 2262 Bytes::put_Java_u2(p, new_index); 2263 } 2264 } break; 2265 default: 2266 break; 2267 } 2268 } // end for each bytecode 2269 } // end rewrite_cp_refs_in_method() 2270 2271 2272 // Rewrite constant pool references in the class_annotations field. 2273 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(InstanceKlass* scratch_class) { 2274 2275 AnnotationArray* class_annotations = scratch_class->class_annotations(); 2276 if (class_annotations == NULL || class_annotations->length() == 0) { 2277 // no class_annotations so nothing to do 2278 return true; 2279 } 2280 2281 log_debug(redefine, class, annotation)("class_annotations length=%d", class_annotations->length()); 2282 2283 int byte_i = 0; // byte index into class_annotations 2284 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i); 2285 } 2286 2287 2288 // Rewrite constant pool references in an annotations typeArray. This 2289 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute 2290 // that is described in section 4.8.15 of the 2nd-edition of the VM spec: 2291 // 2292 // annotations_typeArray { 2293 // u2 num_annotations; 2294 // annotation annotations[num_annotations]; 2295 // } 2296 // 2297 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray( 2298 AnnotationArray* annotations_typeArray, int &byte_i_ref) { 2299 2300 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2301 // not enough room for num_annotations field 2302 log_debug(redefine, class, annotation)("length() is too small for num_annotations field"); 2303 return false; 2304 } 2305 2306 u2 num_annotations = Bytes::get_Java_u2((address) 2307 annotations_typeArray->adr_at(byte_i_ref)); 2308 byte_i_ref += 2; 2309 2310 log_debug(redefine, class, annotation)("num_annotations=%d", num_annotations); 2311 2312 int calc_num_annotations = 0; 2313 for (; calc_num_annotations < num_annotations; calc_num_annotations++) { 2314 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, byte_i_ref)) { 2315 log_debug(redefine, class, annotation)("bad annotation_struct at %d", calc_num_annotations); 2316 // propagate failure back to caller 2317 return false; 2318 } 2319 } 2320 assert(num_annotations == calc_num_annotations, "sanity check"); 2321 2322 return true; 2323 } // end rewrite_cp_refs_in_annotations_typeArray() 2324 2325 2326 // Rewrite constant pool references in the annotation struct portion of 2327 // an annotations_typeArray. This "structure" is from section 4.8.15 of 2328 // the 2nd-edition of the VM spec: 2329 // 2330 // struct annotation { 2331 // u2 type_index; 2332 // u2 num_element_value_pairs; 2333 // { 2334 // u2 element_name_index; 2335 // element_value value; 2336 // } element_value_pairs[num_element_value_pairs]; 2337 // } 2338 // 2339 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct( 2340 AnnotationArray* annotations_typeArray, int &byte_i_ref) { 2341 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) { 2342 // not enough room for smallest annotation_struct 2343 log_debug(redefine, class, annotation)("length() is too small for annotation_struct"); 2344 return false; 2345 } 2346 2347 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray, 2348 byte_i_ref, "type_index"); 2349 2350 u2 num_element_value_pairs = Bytes::get_Java_u2((address) 2351 annotations_typeArray->adr_at(byte_i_ref)); 2352 byte_i_ref += 2; 2353 2354 log_debug(redefine, class, annotation) 2355 ("type_index=%d num_element_value_pairs=%d", type_index, num_element_value_pairs); 2356 2357 int calc_num_element_value_pairs = 0; 2358 for (; calc_num_element_value_pairs < num_element_value_pairs; 2359 calc_num_element_value_pairs++) { 2360 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2361 // not enough room for another element_name_index, let alone 2362 // the rest of another component 2363 log_debug(redefine, class, annotation)("length() is too small for element_name_index"); 2364 return false; 2365 } 2366 2367 u2 element_name_index = rewrite_cp_ref_in_annotation_data( 2368 annotations_typeArray, byte_i_ref, 2369 "element_name_index"); 2370 2371 log_debug(redefine, class, annotation)("element_name_index=%d", element_name_index); 2372 2373 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, byte_i_ref)) { 2374 log_debug(redefine, class, annotation)("bad element_value at %d", calc_num_element_value_pairs); 2375 // propagate failure back to caller 2376 return false; 2377 } 2378 } // end for each component 2379 assert(num_element_value_pairs == calc_num_element_value_pairs, 2380 "sanity check"); 2381 2382 return true; 2383 } // end rewrite_cp_refs_in_annotation_struct() 2384 2385 2386 // Rewrite a constant pool reference at the current position in 2387 // annotations_typeArray if needed. Returns the original constant 2388 // pool reference if a rewrite was not needed or the new constant 2389 // pool reference if a rewrite was needed. 2390 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data( 2391 AnnotationArray* annotations_typeArray, int &byte_i_ref, 2392 const char * trace_mesg) { 2393 2394 address cp_index_addr = (address) 2395 annotations_typeArray->adr_at(byte_i_ref); 2396 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr); 2397 u2 new_cp_index = find_new_index(old_cp_index); 2398 if (new_cp_index != 0) { 2399 log_debug(redefine, class, annotation)("mapped old %s=%d", trace_mesg, old_cp_index); 2400 Bytes::put_Java_u2(cp_index_addr, new_cp_index); 2401 old_cp_index = new_cp_index; 2402 } 2403 byte_i_ref += 2; 2404 return old_cp_index; 2405 } 2406 2407 2408 // Rewrite constant pool references in the element_value portion of an 2409 // annotations_typeArray. This "structure" is from section 4.8.15.1 of 2410 // the 2nd-edition of the VM spec: 2411 // 2412 // struct element_value { 2413 // u1 tag; 2414 // union { 2415 // u2 const_value_index; 2416 // { 2417 // u2 type_name_index; 2418 // u2 const_name_index; 2419 // } enum_const_value; 2420 // u2 class_info_index; 2421 // annotation annotation_value; 2422 // struct { 2423 // u2 num_values; 2424 // element_value values[num_values]; 2425 // } array_value; 2426 // } value; 2427 // } 2428 // 2429 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value( 2430 AnnotationArray* annotations_typeArray, int &byte_i_ref) { 2431 2432 if ((byte_i_ref + 1) > annotations_typeArray->length()) { 2433 // not enough room for a tag let alone the rest of an element_value 2434 log_debug(redefine, class, annotation)("length() is too small for a tag"); 2435 return false; 2436 } 2437 2438 u1 tag = annotations_typeArray->at(byte_i_ref); 2439 byte_i_ref++; 2440 log_debug(redefine, class, annotation)("tag='%c'", tag); 2441 2442 switch (tag) { 2443 // These BaseType tag values are from Table 4.2 in VM spec: 2444 case JVM_SIGNATURE_BYTE: 2445 case JVM_SIGNATURE_CHAR: 2446 case JVM_SIGNATURE_DOUBLE: 2447 case JVM_SIGNATURE_FLOAT: 2448 case JVM_SIGNATURE_INT: 2449 case JVM_SIGNATURE_LONG: 2450 case JVM_SIGNATURE_SHORT: 2451 case JVM_SIGNATURE_BOOLEAN: 2452 2453 // The remaining tag values are from Table 4.8 in the 2nd-edition of 2454 // the VM spec: 2455 case 's': 2456 { 2457 // For the above tag values (including the BaseType values), 2458 // value.const_value_index is right union field. 2459 2460 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2461 // not enough room for a const_value_index 2462 log_debug(redefine, class, annotation)("length() is too small for a const_value_index"); 2463 return false; 2464 } 2465 2466 u2 const_value_index = rewrite_cp_ref_in_annotation_data( 2467 annotations_typeArray, byte_i_ref, 2468 "const_value_index"); 2469 2470 log_debug(redefine, class, annotation)("const_value_index=%d", const_value_index); 2471 } break; 2472 2473 case 'e': 2474 { 2475 // for the above tag value, value.enum_const_value is right union field 2476 2477 if ((byte_i_ref + 4) > annotations_typeArray->length()) { 2478 // not enough room for a enum_const_value 2479 log_debug(redefine, class, annotation)("length() is too small for a enum_const_value"); 2480 return false; 2481 } 2482 2483 u2 type_name_index = rewrite_cp_ref_in_annotation_data( 2484 annotations_typeArray, byte_i_ref, 2485 "type_name_index"); 2486 2487 u2 const_name_index = rewrite_cp_ref_in_annotation_data( 2488 annotations_typeArray, byte_i_ref, 2489 "const_name_index"); 2490 2491 log_debug(redefine, class, annotation) 2492 ("type_name_index=%d const_name_index=%d", type_name_index, const_name_index); 2493 } break; 2494 2495 case 'c': 2496 { 2497 // for the above tag value, value.class_info_index is right union field 2498 2499 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2500 // not enough room for a class_info_index 2501 log_debug(redefine, class, annotation)("length() is too small for a class_info_index"); 2502 return false; 2503 } 2504 2505 u2 class_info_index = rewrite_cp_ref_in_annotation_data( 2506 annotations_typeArray, byte_i_ref, 2507 "class_info_index"); 2508 2509 log_debug(redefine, class, annotation)("class_info_index=%d", class_info_index); 2510 } break; 2511 2512 case '@': 2513 // For the above tag value, value.attr_value is the right union 2514 // field. This is a nested annotation. 2515 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, byte_i_ref)) { 2516 // propagate failure back to caller 2517 return false; 2518 } 2519 break; 2520 2521 case JVM_SIGNATURE_ARRAY: 2522 { 2523 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2524 // not enough room for a num_values field 2525 log_debug(redefine, class, annotation)("length() is too small for a num_values field"); 2526 return false; 2527 } 2528 2529 // For the above tag value, value.array_value is the right union 2530 // field. This is an array of nested element_value. 2531 u2 num_values = Bytes::get_Java_u2((address) 2532 annotations_typeArray->adr_at(byte_i_ref)); 2533 byte_i_ref += 2; 2534 log_debug(redefine, class, annotation)("num_values=%d", num_values); 2535 2536 int calc_num_values = 0; 2537 for (; calc_num_values < num_values; calc_num_values++) { 2538 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, byte_i_ref)) { 2539 log_debug(redefine, class, annotation)("bad nested element_value at %d", calc_num_values); 2540 // propagate failure back to caller 2541 return false; 2542 } 2543 } 2544 assert(num_values == calc_num_values, "sanity check"); 2545 } break; 2546 2547 default: 2548 log_debug(redefine, class, annotation)("bad tag=0x%x", tag); 2549 return false; 2550 } // end decode tag field 2551 2552 return true; 2553 } // end rewrite_cp_refs_in_element_value() 2554 2555 2556 // Rewrite constant pool references in a fields_annotations field. 2557 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations( 2558 InstanceKlass* scratch_class) { 2559 2560 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations(); 2561 2562 if (fields_annotations == NULL || fields_annotations->length() == 0) { 2563 // no fields_annotations so nothing to do 2564 return true; 2565 } 2566 2567 log_debug(redefine, class, annotation)("fields_annotations length=%d", fields_annotations->length()); 2568 2569 for (int i = 0; i < fields_annotations->length(); i++) { 2570 AnnotationArray* field_annotations = fields_annotations->at(i); 2571 if (field_annotations == NULL || field_annotations->length() == 0) { 2572 // this field does not have any annotations so skip it 2573 continue; 2574 } 2575 2576 int byte_i = 0; // byte index into field_annotations 2577 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i)) { 2578 log_debug(redefine, class, annotation)("bad field_annotations at %d", i); 2579 // propagate failure back to caller 2580 return false; 2581 } 2582 } 2583 2584 return true; 2585 } // end rewrite_cp_refs_in_fields_annotations() 2586 2587 2588 // Rewrite constant pool references in a methods_annotations field. 2589 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations( 2590 InstanceKlass* scratch_class) { 2591 2592 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2593 Method* m = scratch_class->methods()->at(i); 2594 AnnotationArray* method_annotations = m->constMethod()->method_annotations(); 2595 2596 if (method_annotations == NULL || method_annotations->length() == 0) { 2597 // this method does not have any annotations so skip it 2598 continue; 2599 } 2600 2601 int byte_i = 0; // byte index into method_annotations 2602 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i)) { 2603 log_debug(redefine, class, annotation)("bad method_annotations at %d", i); 2604 // propagate failure back to caller 2605 return false; 2606 } 2607 } 2608 2609 return true; 2610 } // end rewrite_cp_refs_in_methods_annotations() 2611 2612 2613 // Rewrite constant pool references in a methods_parameter_annotations 2614 // field. This "structure" is adapted from the 2615 // RuntimeVisibleParameterAnnotations_attribute described in section 2616 // 4.8.17 of the 2nd-edition of the VM spec: 2617 // 2618 // methods_parameter_annotations_typeArray { 2619 // u1 num_parameters; 2620 // { 2621 // u2 num_annotations; 2622 // annotation annotations[num_annotations]; 2623 // } parameter_annotations[num_parameters]; 2624 // } 2625 // 2626 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations( 2627 InstanceKlass* scratch_class) { 2628 2629 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2630 Method* m = scratch_class->methods()->at(i); 2631 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations(); 2632 if (method_parameter_annotations == NULL 2633 || method_parameter_annotations->length() == 0) { 2634 // this method does not have any parameter annotations so skip it 2635 continue; 2636 } 2637 2638 if (method_parameter_annotations->length() < 1) { 2639 // not enough room for a num_parameters field 2640 log_debug(redefine, class, annotation)("length() is too small for a num_parameters field at %d", i); 2641 return false; 2642 } 2643 2644 int byte_i = 0; // byte index into method_parameter_annotations 2645 2646 u1 num_parameters = method_parameter_annotations->at(byte_i); 2647 byte_i++; 2648 2649 log_debug(redefine, class, annotation)("num_parameters=%d", num_parameters); 2650 2651 int calc_num_parameters = 0; 2652 for (; calc_num_parameters < num_parameters; calc_num_parameters++) { 2653 if (!rewrite_cp_refs_in_annotations_typeArray(method_parameter_annotations, byte_i)) { 2654 log_debug(redefine, class, annotation)("bad method_parameter_annotations at %d", calc_num_parameters); 2655 // propagate failure back to caller 2656 return false; 2657 } 2658 } 2659 assert(num_parameters == calc_num_parameters, "sanity check"); 2660 } 2661 2662 return true; 2663 } // end rewrite_cp_refs_in_methods_parameter_annotations() 2664 2665 2666 // Rewrite constant pool references in a methods_default_annotations 2667 // field. This "structure" is adapted from the AnnotationDefault_attribute 2668 // that is described in section 4.8.19 of the 2nd-edition of the VM spec: 2669 // 2670 // methods_default_annotations_typeArray { 2671 // element_value default_value; 2672 // } 2673 // 2674 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations( 2675 InstanceKlass* scratch_class) { 2676 2677 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2678 Method* m = scratch_class->methods()->at(i); 2679 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations(); 2680 if (method_default_annotations == NULL 2681 || method_default_annotations->length() == 0) { 2682 // this method does not have any default annotations so skip it 2683 continue; 2684 } 2685 2686 int byte_i = 0; // byte index into method_default_annotations 2687 2688 if (!rewrite_cp_refs_in_element_value( 2689 method_default_annotations, byte_i)) { 2690 log_debug(redefine, class, annotation)("bad default element_value at %d", i); 2691 // propagate failure back to caller 2692 return false; 2693 } 2694 } 2695 2696 return true; 2697 } // end rewrite_cp_refs_in_methods_default_annotations() 2698 2699 2700 // Rewrite constant pool references in a class_type_annotations field. 2701 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations( 2702 InstanceKlass* scratch_class) { 2703 2704 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations(); 2705 if (class_type_annotations == NULL || class_type_annotations->length() == 0) { 2706 // no class_type_annotations so nothing to do 2707 return true; 2708 } 2709 2710 log_debug(redefine, class, annotation)("class_type_annotations length=%d", class_type_annotations->length()); 2711 2712 int byte_i = 0; // byte index into class_type_annotations 2713 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations, 2714 byte_i, "ClassFile"); 2715 } // end rewrite_cp_refs_in_class_type_annotations() 2716 2717 2718 // Rewrite constant pool references in a fields_type_annotations field. 2719 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations(InstanceKlass* scratch_class) { 2720 2721 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations(); 2722 if (fields_type_annotations == NULL || fields_type_annotations->length() == 0) { 2723 // no fields_type_annotations so nothing to do 2724 return true; 2725 } 2726 2727 log_debug(redefine, class, annotation)("fields_type_annotations length=%d", fields_type_annotations->length()); 2728 2729 for (int i = 0; i < fields_type_annotations->length(); i++) { 2730 AnnotationArray* field_type_annotations = fields_type_annotations->at(i); 2731 if (field_type_annotations == NULL || field_type_annotations->length() == 0) { 2732 // this field does not have any annotations so skip it 2733 continue; 2734 } 2735 2736 int byte_i = 0; // byte index into field_type_annotations 2737 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations, 2738 byte_i, "field_info")) { 2739 log_debug(redefine, class, annotation)("bad field_type_annotations at %d", i); 2740 // propagate failure back to caller 2741 return false; 2742 } 2743 } 2744 2745 return true; 2746 } // end rewrite_cp_refs_in_fields_type_annotations() 2747 2748 2749 // Rewrite constant pool references in a methods_type_annotations field. 2750 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations( 2751 InstanceKlass* scratch_class) { 2752 2753 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2754 Method* m = scratch_class->methods()->at(i); 2755 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations(); 2756 2757 if (method_type_annotations == NULL || method_type_annotations->length() == 0) { 2758 // this method does not have any annotations so skip it 2759 continue; 2760 } 2761 2762 log_debug(redefine, class, annotation)("methods type_annotations length=%d", method_type_annotations->length()); 2763 2764 int byte_i = 0; // byte index into method_type_annotations 2765 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations, 2766 byte_i, "method_info")) { 2767 log_debug(redefine, class, annotation)("bad method_type_annotations at %d", i); 2768 // propagate failure back to caller 2769 return false; 2770 } 2771 } 2772 2773 return true; 2774 } // end rewrite_cp_refs_in_methods_type_annotations() 2775 2776 2777 // Rewrite constant pool references in a type_annotations 2778 // field. This "structure" is adapted from the 2779 // RuntimeVisibleTypeAnnotations_attribute described in 2780 // section 4.7.20 of the Java SE 8 Edition of the VM spec: 2781 // 2782 // type_annotations_typeArray { 2783 // u2 num_annotations; 2784 // type_annotation annotations[num_annotations]; 2785 // } 2786 // 2787 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray( 2788 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2789 const char * location_mesg) { 2790 2791 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2792 // not enough room for num_annotations field 2793 log_debug(redefine, class, annotation)("length() is too small for num_annotations field"); 2794 return false; 2795 } 2796 2797 u2 num_annotations = Bytes::get_Java_u2((address) 2798 type_annotations_typeArray->adr_at(byte_i_ref)); 2799 byte_i_ref += 2; 2800 2801 log_debug(redefine, class, annotation)("num_type_annotations=%d", num_annotations); 2802 2803 int calc_num_annotations = 0; 2804 for (; calc_num_annotations < num_annotations; calc_num_annotations++) { 2805 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray, 2806 byte_i_ref, location_mesg)) { 2807 log_debug(redefine, class, annotation)("bad type_annotation_struct at %d", calc_num_annotations); 2808 // propagate failure back to caller 2809 return false; 2810 } 2811 } 2812 assert(num_annotations == calc_num_annotations, "sanity check"); 2813 2814 if (byte_i_ref != type_annotations_typeArray->length()) { 2815 log_debug(redefine, class, annotation) 2816 ("read wrong amount of bytes at end of processing type_annotations_typeArray (%d of %d bytes were read)", 2817 byte_i_ref, type_annotations_typeArray->length()); 2818 return false; 2819 } 2820 2821 return true; 2822 } // end rewrite_cp_refs_in_type_annotations_typeArray() 2823 2824 2825 // Rewrite constant pool references in a type_annotation 2826 // field. This "structure" is adapted from the 2827 // RuntimeVisibleTypeAnnotations_attribute described in 2828 // section 4.7.20 of the Java SE 8 Edition of the VM spec: 2829 // 2830 // type_annotation { 2831 // u1 target_type; 2832 // union { 2833 // type_parameter_target; 2834 // supertype_target; 2835 // type_parameter_bound_target; 2836 // empty_target; 2837 // method_formal_parameter_target; 2838 // throws_target; 2839 // localvar_target; 2840 // catch_target; 2841 // offset_target; 2842 // type_argument_target; 2843 // } target_info; 2844 // type_path target_path; 2845 // annotation anno; 2846 // } 2847 // 2848 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct( 2849 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2850 const char * location_mesg) { 2851 2852 if (!skip_type_annotation_target(type_annotations_typeArray, 2853 byte_i_ref, location_mesg)) { 2854 return false; 2855 } 2856 2857 if (!skip_type_annotation_type_path(type_annotations_typeArray, byte_i_ref)) { 2858 return false; 2859 } 2860 2861 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray, byte_i_ref)) { 2862 return false; 2863 } 2864 2865 return true; 2866 } // end rewrite_cp_refs_in_type_annotation_struct() 2867 2868 2869 // Read, verify and skip over the target_type and target_info part 2870 // so that rewriting can continue in the later parts of the struct. 2871 // 2872 // u1 target_type; 2873 // union { 2874 // type_parameter_target; 2875 // supertype_target; 2876 // type_parameter_bound_target; 2877 // empty_target; 2878 // method_formal_parameter_target; 2879 // throws_target; 2880 // localvar_target; 2881 // catch_target; 2882 // offset_target; 2883 // type_argument_target; 2884 // } target_info; 2885 // 2886 bool VM_RedefineClasses::skip_type_annotation_target( 2887 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2888 const char * location_mesg) { 2889 2890 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2891 // not enough room for a target_type let alone the rest of a type_annotation 2892 log_debug(redefine, class, annotation)("length() is too small for a target_type"); 2893 return false; 2894 } 2895 2896 u1 target_type = type_annotations_typeArray->at(byte_i_ref); 2897 byte_i_ref += 1; 2898 log_debug(redefine, class, annotation)("target_type=0x%.2x", target_type); 2899 log_debug(redefine, class, annotation)("location=%s", location_mesg); 2900 2901 // Skip over target_info 2902 switch (target_type) { 2903 case 0x00: 2904 // kind: type parameter declaration of generic class or interface 2905 // location: ClassFile 2906 case 0x01: 2907 // kind: type parameter declaration of generic method or constructor 2908 // location: method_info 2909 2910 { 2911 // struct: 2912 // type_parameter_target { 2913 // u1 type_parameter_index; 2914 // } 2915 // 2916 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2917 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_target"); 2918 return false; 2919 } 2920 2921 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2922 byte_i_ref += 1; 2923 2924 log_debug(redefine, class, annotation)("type_parameter_target: type_parameter_index=%d", type_parameter_index); 2925 } break; 2926 2927 case 0x10: 2928 // kind: type in extends clause of class or interface declaration 2929 // or in implements clause of interface declaration 2930 // location: ClassFile 2931 2932 { 2933 // struct: 2934 // supertype_target { 2935 // u2 supertype_index; 2936 // } 2937 // 2938 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2939 log_debug(redefine, class, annotation)("length() is too small for a supertype_target"); 2940 return false; 2941 } 2942 2943 u2 supertype_index = Bytes::get_Java_u2((address) 2944 type_annotations_typeArray->adr_at(byte_i_ref)); 2945 byte_i_ref += 2; 2946 2947 log_debug(redefine, class, annotation)("supertype_target: supertype_index=%d", supertype_index); 2948 } break; 2949 2950 case 0x11: 2951 // kind: type in bound of type parameter declaration of generic class or interface 2952 // location: ClassFile 2953 case 0x12: 2954 // kind: type in bound of type parameter declaration of generic method or constructor 2955 // location: method_info 2956 2957 { 2958 // struct: 2959 // type_parameter_bound_target { 2960 // u1 type_parameter_index; 2961 // u1 bound_index; 2962 // } 2963 // 2964 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2965 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_bound_target"); 2966 return false; 2967 } 2968 2969 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2970 byte_i_ref += 1; 2971 u1 bound_index = type_annotations_typeArray->at(byte_i_ref); 2972 byte_i_ref += 1; 2973 2974 log_debug(redefine, class, annotation) 2975 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d", type_parameter_index, bound_index); 2976 } break; 2977 2978 case 0x13: 2979 // kind: type in field declaration 2980 // location: field_info 2981 case 0x14: 2982 // kind: return type of method, or type of newly constructed object 2983 // location: method_info 2984 case 0x15: 2985 // kind: receiver type of method or constructor 2986 // location: method_info 2987 2988 { 2989 // struct: 2990 // empty_target { 2991 // } 2992 // 2993 log_debug(redefine, class, annotation)("empty_target"); 2994 } break; 2995 2996 case 0x16: 2997 // kind: type in formal parameter declaration of method, constructor, or lambda expression 2998 // location: method_info 2999 3000 { 3001 // struct: 3002 // formal_parameter_target { 3003 // u1 formal_parameter_index; 3004 // } 3005 // 3006 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 3007 log_debug(redefine, class, annotation)("length() is too small for a formal_parameter_target"); 3008 return false; 3009 } 3010 3011 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref); 3012 byte_i_ref += 1; 3013 3014 log_debug(redefine, class, annotation) 3015 ("formal_parameter_target: formal_parameter_index=%d", formal_parameter_index); 3016 } break; 3017 3018 case 0x17: 3019 // kind: type in throws clause of method or constructor 3020 // location: method_info 3021 3022 { 3023 // struct: 3024 // throws_target { 3025 // u2 throws_type_index 3026 // } 3027 // 3028 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 3029 log_debug(redefine, class, annotation)("length() is too small for a throws_target"); 3030 return false; 3031 } 3032 3033 u2 throws_type_index = Bytes::get_Java_u2((address) 3034 type_annotations_typeArray->adr_at(byte_i_ref)); 3035 byte_i_ref += 2; 3036 3037 log_debug(redefine, class, annotation)("throws_target: throws_type_index=%d", throws_type_index); 3038 } break; 3039 3040 case 0x40: 3041 // kind: type in local variable declaration 3042 // location: Code 3043 case 0x41: 3044 // kind: type in resource variable declaration 3045 // location: Code 3046 3047 { 3048 // struct: 3049 // localvar_target { 3050 // u2 table_length; 3051 // struct { 3052 // u2 start_pc; 3053 // u2 length; 3054 // u2 index; 3055 // } table[table_length]; 3056 // } 3057 // 3058 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 3059 // not enough room for a table_length let alone the rest of a localvar_target 3060 log_debug(redefine, class, annotation)("length() is too small for a localvar_target table_length"); 3061 return false; 3062 } 3063 3064 u2 table_length = Bytes::get_Java_u2((address) 3065 type_annotations_typeArray->adr_at(byte_i_ref)); 3066 byte_i_ref += 2; 3067 3068 log_debug(redefine, class, annotation)("localvar_target: table_length=%d", table_length); 3069 3070 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry 3071 int table_size = table_length * table_struct_size; 3072 3073 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) { 3074 // not enough room for a table 3075 log_debug(redefine, class, annotation)("length() is too small for a table array of length %d", table_length); 3076 return false; 3077 } 3078 3079 // Skip over table 3080 byte_i_ref += table_size; 3081 } break; 3082 3083 case 0x42: 3084 // kind: type in exception parameter declaration 3085 // location: Code 3086 3087 { 3088 // struct: 3089 // catch_target { 3090 // u2 exception_table_index; 3091 // } 3092 // 3093 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 3094 log_debug(redefine, class, annotation)("length() is too small for a catch_target"); 3095 return false; 3096 } 3097 3098 u2 exception_table_index = Bytes::get_Java_u2((address) 3099 type_annotations_typeArray->adr_at(byte_i_ref)); 3100 byte_i_ref += 2; 3101 3102 log_debug(redefine, class, annotation)("catch_target: exception_table_index=%d", exception_table_index); 3103 } break; 3104 3105 case 0x43: 3106 // kind: type in instanceof expression 3107 // location: Code 3108 case 0x44: 3109 // kind: type in new expression 3110 // location: Code 3111 case 0x45: 3112 // kind: type in method reference expression using ::new 3113 // location: Code 3114 case 0x46: 3115 // kind: type in method reference expression using ::Identifier 3116 // location: Code 3117 3118 { 3119 // struct: 3120 // offset_target { 3121 // u2 offset; 3122 // } 3123 // 3124 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 3125 log_debug(redefine, class, annotation)("length() is too small for a offset_target"); 3126 return false; 3127 } 3128 3129 u2 offset = Bytes::get_Java_u2((address) 3130 type_annotations_typeArray->adr_at(byte_i_ref)); 3131 byte_i_ref += 2; 3132 3133 log_debug(redefine, class, annotation)("offset_target: offset=%d", offset); 3134 } break; 3135 3136 case 0x47: 3137 // kind: type in cast expression 3138 // location: Code 3139 case 0x48: 3140 // kind: type argument for generic constructor in new expression or 3141 // explicit constructor invocation statement 3142 // location: Code 3143 case 0x49: 3144 // kind: type argument for generic method in method invocation expression 3145 // location: Code 3146 case 0x4A: 3147 // kind: type argument for generic constructor in method reference expression using ::new 3148 // location: Code 3149 case 0x4B: 3150 // kind: type argument for generic method in method reference expression using ::Identifier 3151 // location: Code 3152 3153 { 3154 // struct: 3155 // type_argument_target { 3156 // u2 offset; 3157 // u1 type_argument_index; 3158 // } 3159 // 3160 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) { 3161 log_debug(redefine, class, annotation)("length() is too small for a type_argument_target"); 3162 return false; 3163 } 3164 3165 u2 offset = Bytes::get_Java_u2((address) 3166 type_annotations_typeArray->adr_at(byte_i_ref)); 3167 byte_i_ref += 2; 3168 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref); 3169 byte_i_ref += 1; 3170 3171 log_debug(redefine, class, annotation) 3172 ("type_argument_target: offset=%d, type_argument_index=%d", offset, type_argument_index); 3173 } break; 3174 3175 default: 3176 log_debug(redefine, class, annotation)("unknown target_type"); 3177 #ifdef ASSERT 3178 ShouldNotReachHere(); 3179 #endif 3180 return false; 3181 } 3182 3183 return true; 3184 } // end skip_type_annotation_target() 3185 3186 3187 // Read, verify and skip over the type_path part so that rewriting 3188 // can continue in the later parts of the struct. 3189 // 3190 // type_path { 3191 // u1 path_length; 3192 // { 3193 // u1 type_path_kind; 3194 // u1 type_argument_index; 3195 // } path[path_length]; 3196 // } 3197 // 3198 bool VM_RedefineClasses::skip_type_annotation_type_path( 3199 AnnotationArray* type_annotations_typeArray, int &byte_i_ref) { 3200 3201 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 3202 // not enough room for a path_length let alone the rest of the type_path 3203 log_debug(redefine, class, annotation)("length() is too small for a type_path"); 3204 return false; 3205 } 3206 3207 u1 path_length = type_annotations_typeArray->at(byte_i_ref); 3208 byte_i_ref += 1; 3209 3210 log_debug(redefine, class, annotation)("type_path: path_length=%d", path_length); 3211 3212 int calc_path_length = 0; 3213 for (; calc_path_length < path_length; calc_path_length++) { 3214 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) { 3215 // not enough room for a path 3216 log_debug(redefine, class, annotation) 3217 ("length() is too small for path entry %d of %d", calc_path_length, path_length); 3218 return false; 3219 } 3220 3221 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref); 3222 byte_i_ref += 1; 3223 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref); 3224 byte_i_ref += 1; 3225 3226 log_debug(redefine, class, annotation) 3227 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d", 3228 calc_path_length, type_path_kind, type_argument_index); 3229 3230 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) { 3231 // not enough room for a path 3232 log_debug(redefine, class, annotation)("inconsistent type_path values"); 3233 return false; 3234 } 3235 } 3236 assert(path_length == calc_path_length, "sanity check"); 3237 3238 return true; 3239 } // end skip_type_annotation_type_path() 3240 3241 3242 // Rewrite constant pool references in the method's stackmap table. 3243 // These "structures" are adapted from the StackMapTable_attribute that 3244 // is described in section 4.8.4 of the 6.0 version of the VM spec 3245 // (dated 2005.10.26): 3246 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf 3247 // 3248 // stack_map { 3249 // u2 number_of_entries; 3250 // stack_map_frame entries[number_of_entries]; 3251 // } 3252 // 3253 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table( 3254 const methodHandle& method) { 3255 3256 if (!method->has_stackmap_table()) { 3257 return; 3258 } 3259 3260 AnnotationArray* stackmap_data = method->stackmap_data(); 3261 address stackmap_p = (address)stackmap_data->adr_at(0); 3262 address stackmap_end = stackmap_p + stackmap_data->length(); 3263 3264 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries"); 3265 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p); 3266 stackmap_p += 2; 3267 3268 log_debug(redefine, class, stackmap)("number_of_entries=%u", number_of_entries); 3269 3270 // walk through each stack_map_frame 3271 u2 calc_number_of_entries = 0; 3272 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) { 3273 // The stack_map_frame structure is a u1 frame_type followed by 3274 // 0 or more bytes of data: 3275 // 3276 // union stack_map_frame { 3277 // same_frame; 3278 // same_locals_1_stack_item_frame; 3279 // same_locals_1_stack_item_frame_extended; 3280 // chop_frame; 3281 // same_frame_extended; 3282 // append_frame; 3283 // full_frame; 3284 // } 3285 3286 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type"); 3287 u1 frame_type = *stackmap_p; 3288 stackmap_p++; 3289 3290 // same_frame { 3291 // u1 frame_type = SAME; /* 0-63 */ 3292 // } 3293 if (frame_type <= 63) { 3294 // nothing more to do for same_frame 3295 } 3296 3297 // same_locals_1_stack_item_frame { 3298 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */ 3299 // verification_type_info stack[1]; 3300 // } 3301 else if (frame_type >= 64 && frame_type <= 127) { 3302 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3303 calc_number_of_entries, frame_type); 3304 } 3305 3306 // reserved for future use 3307 else if (frame_type >= 128 && frame_type <= 246) { 3308 // nothing more to do for reserved frame_types 3309 } 3310 3311 // same_locals_1_stack_item_frame_extended { 3312 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */ 3313 // u2 offset_delta; 3314 // verification_type_info stack[1]; 3315 // } 3316 else if (frame_type == 247) { 3317 stackmap_p += 2; 3318 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3319 calc_number_of_entries, frame_type); 3320 } 3321 3322 // chop_frame { 3323 // u1 frame_type = CHOP; /* 248-250 */ 3324 // u2 offset_delta; 3325 // } 3326 else if (frame_type >= 248 && frame_type <= 250) { 3327 stackmap_p += 2; 3328 } 3329 3330 // same_frame_extended { 3331 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/ 3332 // u2 offset_delta; 3333 // } 3334 else if (frame_type == 251) { 3335 stackmap_p += 2; 3336 } 3337 3338 // append_frame { 3339 // u1 frame_type = APPEND; /* 252-254 */ 3340 // u2 offset_delta; 3341 // verification_type_info locals[frame_type - 251]; 3342 // } 3343 else if (frame_type >= 252 && frame_type <= 254) { 3344 assert(stackmap_p + 2 <= stackmap_end, 3345 "no room for offset_delta"); 3346 stackmap_p += 2; 3347 u1 len = frame_type - 251; 3348 for (u1 i = 0; i < len; i++) { 3349 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3350 calc_number_of_entries, frame_type); 3351 } 3352 } 3353 3354 // full_frame { 3355 // u1 frame_type = FULL_FRAME; /* 255 */ 3356 // u2 offset_delta; 3357 // u2 number_of_locals; 3358 // verification_type_info locals[number_of_locals]; 3359 // u2 number_of_stack_items; 3360 // verification_type_info stack[number_of_stack_items]; 3361 // } 3362 else if (frame_type == 255) { 3363 assert(stackmap_p + 2 + 2 <= stackmap_end, 3364 "no room for smallest full_frame"); 3365 stackmap_p += 2; 3366 3367 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p); 3368 stackmap_p += 2; 3369 3370 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) { 3371 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3372 calc_number_of_entries, frame_type); 3373 } 3374 3375 // Use the largest size for the number_of_stack_items, but only get 3376 // the right number of bytes. 3377 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p); 3378 stackmap_p += 2; 3379 3380 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) { 3381 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3382 calc_number_of_entries, frame_type); 3383 } 3384 } 3385 } // end while there is a stack_map_frame 3386 assert(number_of_entries == calc_number_of_entries, "sanity check"); 3387 } // end rewrite_cp_refs_in_stack_map_table() 3388 3389 3390 // Rewrite constant pool references in the verification type info 3391 // portion of the method's stackmap table. These "structures" are 3392 // adapted from the StackMapTable_attribute that is described in 3393 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26): 3394 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf 3395 // 3396 // The verification_type_info structure is a u1 tag followed by 0 or 3397 // more bytes of data: 3398 // 3399 // union verification_type_info { 3400 // Top_variable_info; 3401 // Integer_variable_info; 3402 // Float_variable_info; 3403 // Long_variable_info; 3404 // Double_variable_info; 3405 // Null_variable_info; 3406 // UninitializedThis_variable_info; 3407 // Object_variable_info; 3408 // Uninitialized_variable_info; 3409 // } 3410 // 3411 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info( 3412 address& stackmap_p_ref, address stackmap_end, u2 frame_i, 3413 u1 frame_type) { 3414 3415 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag"); 3416 u1 tag = *stackmap_p_ref; 3417 stackmap_p_ref++; 3418 3419 switch (tag) { 3420 // Top_variable_info { 3421 // u1 tag = ITEM_Top; /* 0 */ 3422 // } 3423 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top 3424 case 0: // fall through 3425 3426 // Integer_variable_info { 3427 // u1 tag = ITEM_Integer; /* 1 */ 3428 // } 3429 case ITEM_Integer: // fall through 3430 3431 // Float_variable_info { 3432 // u1 tag = ITEM_Float; /* 2 */ 3433 // } 3434 case ITEM_Float: // fall through 3435 3436 // Double_variable_info { 3437 // u1 tag = ITEM_Double; /* 3 */ 3438 // } 3439 case ITEM_Double: // fall through 3440 3441 // Long_variable_info { 3442 // u1 tag = ITEM_Long; /* 4 */ 3443 // } 3444 case ITEM_Long: // fall through 3445 3446 // Null_variable_info { 3447 // u1 tag = ITEM_Null; /* 5 */ 3448 // } 3449 case ITEM_Null: // fall through 3450 3451 // UninitializedThis_variable_info { 3452 // u1 tag = ITEM_UninitializedThis; /* 6 */ 3453 // } 3454 case ITEM_UninitializedThis: 3455 // nothing more to do for the above tag types 3456 break; 3457 3458 // Object_variable_info { 3459 // u1 tag = ITEM_Object; /* 7 */ 3460 // u2 cpool_index; 3461 // } 3462 case ITEM_Object: 3463 { 3464 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index"); 3465 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref); 3466 u2 new_cp_index = find_new_index(cpool_index); 3467 if (new_cp_index != 0) { 3468 log_debug(redefine, class, stackmap)("mapped old cpool_index=%d", cpool_index); 3469 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index); 3470 cpool_index = new_cp_index; 3471 } 3472 stackmap_p_ref += 2; 3473 3474 log_debug(redefine, class, stackmap) 3475 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i, frame_type, cpool_index); 3476 } break; 3477 3478 // Uninitialized_variable_info { 3479 // u1 tag = ITEM_Uninitialized; /* 8 */ 3480 // u2 offset; 3481 // } 3482 case ITEM_Uninitialized: 3483 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset"); 3484 stackmap_p_ref += 2; 3485 break; 3486 3487 default: 3488 log_debug(redefine, class, stackmap)("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag); 3489 ShouldNotReachHere(); 3490 break; 3491 } // end switch (tag) 3492 } // end rewrite_cp_refs_in_verification_type_info() 3493 3494 3495 // Change the constant pool associated with klass scratch_class to 3496 // scratch_cp. If shrink is true, then scratch_cp_length elements 3497 // are copied from scratch_cp to a smaller constant pool and the 3498 // smaller constant pool is associated with scratch_class. 3499 void VM_RedefineClasses::set_new_constant_pool( 3500 ClassLoaderData* loader_data, 3501 InstanceKlass* scratch_class, constantPoolHandle scratch_cp, 3502 int scratch_cp_length, TRAPS) { 3503 assert(scratch_cp->length() >= scratch_cp_length, "sanity check"); 3504 3505 // scratch_cp is a merged constant pool and has enough space for a 3506 // worst case merge situation. We want to associate the minimum 3507 // sized constant pool with the klass to save space. 3508 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK); 3509 constantPoolHandle smaller_cp(THREAD, cp); 3510 3511 // preserve version() value in the smaller copy 3512 int version = scratch_cp->version(); 3513 assert(version != 0, "sanity check"); 3514 smaller_cp->set_version(version); 3515 3516 // attach klass to new constant pool 3517 // reference to the cp holder is needed for copy_operands() 3518 smaller_cp->set_pool_holder(scratch_class); 3519 3520 smaller_cp->copy_fields(scratch_cp()); 3521 3522 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD); 3523 if (HAS_PENDING_EXCEPTION) { 3524 // Exception is handled in the caller 3525 loader_data->add_to_deallocate_list(smaller_cp()); 3526 return; 3527 } 3528 scratch_cp = smaller_cp; 3529 3530 // attach new constant pool to klass 3531 scratch_class->set_constants(scratch_cp()); 3532 scratch_cp->initialize_unresolved_klasses(loader_data, CHECK); 3533 3534 int i; // for portability 3535 3536 // update each field in klass to use new constant pool indices as needed 3537 for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) { 3538 jshort cur_index = fs.name_index(); 3539 jshort new_index = find_new_index(cur_index); 3540 if (new_index != 0) { 3541 log_trace(redefine, class, constantpool)("field-name_index change: %d to %d", cur_index, new_index); 3542 fs.set_name_index(new_index); 3543 } 3544 cur_index = fs.signature_index(); 3545 new_index = find_new_index(cur_index); 3546 if (new_index != 0) { 3547 log_trace(redefine, class, constantpool)("field-signature_index change: %d to %d", cur_index, new_index); 3548 fs.set_signature_index(new_index); 3549 } 3550 cur_index = fs.initval_index(); 3551 new_index = find_new_index(cur_index); 3552 if (new_index != 0) { 3553 log_trace(redefine, class, constantpool)("field-initval_index change: %d to %d", cur_index, new_index); 3554 fs.set_initval_index(new_index); 3555 } 3556 cur_index = fs.generic_signature_index(); 3557 new_index = find_new_index(cur_index); 3558 if (new_index != 0) { 3559 log_trace(redefine, class, constantpool)("field-generic_signature change: %d to %d", cur_index, new_index); 3560 fs.set_generic_signature_index(new_index); 3561 } 3562 } // end for each field 3563 3564 // Update constant pool indices in the inner classes info to use 3565 // new constant indices as needed. The inner classes info is a 3566 // quadruple: 3567 // (inner_class_info, outer_class_info, inner_name, inner_access_flags) 3568 InnerClassesIterator iter(scratch_class); 3569 for (; !iter.done(); iter.next()) { 3570 int cur_index = iter.inner_class_info_index(); 3571 if (cur_index == 0) { 3572 continue; // JVM spec. allows null inner class refs so skip it 3573 } 3574 int new_index = find_new_index(cur_index); 3575 if (new_index != 0) { 3576 log_trace(redefine, class, constantpool)("inner_class_info change: %d to %d", cur_index, new_index); 3577 iter.set_inner_class_info_index(new_index); 3578 } 3579 cur_index = iter.outer_class_info_index(); 3580 new_index = find_new_index(cur_index); 3581 if (new_index != 0) { 3582 log_trace(redefine, class, constantpool)("outer_class_info change: %d to %d", cur_index, new_index); 3583 iter.set_outer_class_info_index(new_index); 3584 } 3585 cur_index = iter.inner_name_index(); 3586 new_index = find_new_index(cur_index); 3587 if (new_index != 0) { 3588 log_trace(redefine, class, constantpool)("inner_name change: %d to %d", cur_index, new_index); 3589 iter.set_inner_name_index(new_index); 3590 } 3591 } // end for each inner class 3592 3593 // Attach each method in klass to the new constant pool and update 3594 // to use new constant pool indices as needed: 3595 Array<Method*>* methods = scratch_class->methods(); 3596 for (i = methods->length() - 1; i >= 0; i--) { 3597 methodHandle method(THREAD, methods->at(i)); 3598 method->set_constants(scratch_cp()); 3599 3600 int new_index = find_new_index(method->name_index()); 3601 if (new_index != 0) { 3602 log_trace(redefine, class, constantpool) 3603 ("method-name_index change: %d to %d", method->name_index(), new_index); 3604 method->set_name_index(new_index); 3605 } 3606 new_index = find_new_index(method->signature_index()); 3607 if (new_index != 0) { 3608 log_trace(redefine, class, constantpool) 3609 ("method-signature_index change: %d to %d", method->signature_index(), new_index); 3610 method->set_signature_index(new_index); 3611 } 3612 new_index = find_new_index(method->generic_signature_index()); 3613 if (new_index != 0) { 3614 log_trace(redefine, class, constantpool) 3615 ("method-generic_signature_index change: %d to %d", method->generic_signature_index(), new_index); 3616 method->set_generic_signature_index(new_index); 3617 } 3618 3619 // Update constant pool indices in the method's checked exception 3620 // table to use new constant indices as needed. 3621 int cext_length = method->checked_exceptions_length(); 3622 if (cext_length > 0) { 3623 CheckedExceptionElement * cext_table = 3624 method->checked_exceptions_start(); 3625 for (int j = 0; j < cext_length; j++) { 3626 int cur_index = cext_table[j].class_cp_index; 3627 int new_index = find_new_index(cur_index); 3628 if (new_index != 0) { 3629 log_trace(redefine, class, constantpool)("cext-class_cp_index change: %d to %d", cur_index, new_index); 3630 cext_table[j].class_cp_index = (u2)new_index; 3631 } 3632 } // end for each checked exception table entry 3633 } // end if there are checked exception table entries 3634 3635 // Update each catch type index in the method's exception table 3636 // to use new constant pool indices as needed. The exception table 3637 // holds quadruple entries of the form: 3638 // (beg_bci, end_bci, handler_bci, klass_index) 3639 3640 ExceptionTable ex_table(method()); 3641 int ext_length = ex_table.length(); 3642 3643 for (int j = 0; j < ext_length; j ++) { 3644 int cur_index = ex_table.catch_type_index(j); 3645 int new_index = find_new_index(cur_index); 3646 if (new_index != 0) { 3647 log_trace(redefine, class, constantpool)("ext-klass_index change: %d to %d", cur_index, new_index); 3648 ex_table.set_catch_type_index(j, new_index); 3649 } 3650 } // end for each exception table entry 3651 3652 // Update constant pool indices in the method's local variable 3653 // table to use new constant indices as needed. The local variable 3654 // table hold sextuple entries of the form: 3655 // (start_pc, length, name_index, descriptor_index, signature_index, slot) 3656 int lvt_length = method->localvariable_table_length(); 3657 if (lvt_length > 0) { 3658 LocalVariableTableElement * lv_table = 3659 method->localvariable_table_start(); 3660 for (int j = 0; j < lvt_length; j++) { 3661 int cur_index = lv_table[j].name_cp_index; 3662 int new_index = find_new_index(cur_index); 3663 if (new_index != 0) { 3664 log_trace(redefine, class, constantpool)("lvt-name_cp_index change: %d to %d", cur_index, new_index); 3665 lv_table[j].name_cp_index = (u2)new_index; 3666 } 3667 cur_index = lv_table[j].descriptor_cp_index; 3668 new_index = find_new_index(cur_index); 3669 if (new_index != 0) { 3670 log_trace(redefine, class, constantpool)("lvt-descriptor_cp_index change: %d to %d", cur_index, new_index); 3671 lv_table[j].descriptor_cp_index = (u2)new_index; 3672 } 3673 cur_index = lv_table[j].signature_cp_index; 3674 new_index = find_new_index(cur_index); 3675 if (new_index != 0) { 3676 log_trace(redefine, class, constantpool)("lvt-signature_cp_index change: %d to %d", cur_index, new_index); 3677 lv_table[j].signature_cp_index = (u2)new_index; 3678 } 3679 } // end for each local variable table entry 3680 } // end if there are local variable table entries 3681 3682 // Update constant pool indices in the method's method_parameters. 3683 int mp_length = method->method_parameters_length(); 3684 if (mp_length > 0) { 3685 MethodParametersElement* elem = method->method_parameters_start(); 3686 for (int j = 0; j < mp_length; j++) { 3687 const int cp_index = elem[j].name_cp_index; 3688 const int new_cp_index = find_new_index(cp_index); 3689 if (new_cp_index != 0) { 3690 elem[j].name_cp_index = (u2)new_cp_index; 3691 } 3692 } 3693 } 3694 3695 rewrite_cp_refs_in_stack_map_table(method); 3696 } // end for each method 3697 } // end set_new_constant_pool() 3698 3699 3700 // Unevolving classes may point to methods of the_class directly 3701 // from their constant pool caches, itables, and/or vtables. We 3702 // use the ClassLoaderDataGraph::classes_do() facility and this helper 3703 // to fix up these pointers. MethodData also points to old methods and 3704 // must be cleaned. 3705 3706 // Adjust cpools and vtables closure 3707 void VM_RedefineClasses::AdjustAndCleanMetadata::do_klass(Klass* k) { 3708 3709 // This is a very busy routine. We don't want too much tracing 3710 // printed out. 3711 bool trace_name_printed = false; 3712 3713 // If the class being redefined is java.lang.Object, we need to fix all 3714 // array class vtables also. The _has_redefined_Object flag is global. 3715 // Once the java.lang.Object has been redefined (by the current or one 3716 // of the previous VM_RedefineClasses operations) we have to always 3717 // adjust method entries for array classes. 3718 if (k->is_array_klass() && _has_redefined_Object) { 3719 k->vtable().adjust_method_entries(&trace_name_printed); 3720 3721 } else if (k->is_instance_klass()) { 3722 HandleMark hm(_thread); 3723 InstanceKlass *ik = InstanceKlass::cast(k); 3724 3725 // Clean MethodData of this class's methods so they don't refer to 3726 // old methods that are no longer running. 3727 Array<Method*>* methods = ik->methods(); 3728 int num_methods = methods->length(); 3729 for (int index = 0; index < num_methods; ++index) { 3730 if (methods->at(index)->method_data() != NULL) { 3731 methods->at(index)->method_data()->clean_weak_method_links(); 3732 } 3733 } 3734 3735 // Adjust all vtables, default methods and itables, to clean out old methods. 3736 ResourceMark rm(_thread); 3737 if (ik->vtable_length() > 0) { 3738 ik->vtable().adjust_method_entries(&trace_name_printed); 3739 ik->adjust_default_methods(&trace_name_printed); 3740 } 3741 3742 if (ik->itable_length() > 0) { 3743 ik->itable().adjust_method_entries(&trace_name_printed); 3744 } 3745 3746 // The constant pools in other classes (other_cp) can refer to 3747 // old methods. We have to update method information in 3748 // other_cp's cache. If other_cp has a previous version, then we 3749 // have to repeat the process for each previous version. The 3750 // constant pool cache holds the Method*s for non-virtual 3751 // methods and for virtual, final methods. 3752 // 3753 // Special case: if the current class is being redefined by the current 3754 // VM_RedefineClasses operation, then new_cp has already been attached 3755 // to the_class and old_cp has already been added as a previous version. 3756 // The new_cp doesn't have any cached references to old methods so it 3757 // doesn't need to be updated and we could optimize by skipping it. 3758 // However, the current class can be marked as being redefined by another 3759 // VM_RedefineClasses operation which has already executed its doit_prologue 3760 // and needs cpcache method entries adjusted. For simplicity, the cpcache 3761 // update is done unconditionally. It should result in doing nothing for 3762 // classes being redefined by the current VM_RedefineClasses operation. 3763 // Method entries in the previous version(s) are adjusted as well. 3764 ConstantPoolCache* cp_cache; 3765 3766 // this klass' constant pool cache may need adjustment 3767 ConstantPool* other_cp = ik->constants(); 3768 cp_cache = other_cp->cache(); 3769 if (cp_cache != NULL) { 3770 cp_cache->adjust_method_entries(&trace_name_printed); 3771 } 3772 3773 // the previous versions' constant pool caches may need adjustment 3774 for (InstanceKlass* pv_node = ik->previous_versions(); 3775 pv_node != NULL; 3776 pv_node = pv_node->previous_versions()) { 3777 cp_cache = pv_node->constants()->cache(); 3778 if (cp_cache != NULL) { 3779 cp_cache->adjust_method_entries(&trace_name_printed); 3780 } 3781 } 3782 } 3783 } 3784 3785 void VM_RedefineClasses::update_jmethod_ids() { 3786 for (int j = 0; j < _matching_methods_length; ++j) { 3787 Method* old_method = _matching_old_methods[j]; 3788 jmethodID jmid = old_method->find_jmethod_id_or_null(); 3789 if (jmid != NULL) { 3790 // There is a jmethodID, change it to point to the new method 3791 Method* new_method = _matching_new_methods[j]; 3792 Method::change_method_associated_with_jmethod_id(jmid, new_method); 3793 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j], 3794 "should be replaced"); 3795 } 3796 } 3797 } 3798 3799 int VM_RedefineClasses::check_methods_and_mark_as_obsolete() { 3800 int emcp_method_count = 0; 3801 int obsolete_count = 0; 3802 int old_index = 0; 3803 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) { 3804 Method* old_method = _matching_old_methods[j]; 3805 Method* new_method = _matching_new_methods[j]; 3806 Method* old_array_method; 3807 3808 // Maintain an old_index into the _old_methods array by skipping 3809 // deleted methods 3810 while ((old_array_method = _old_methods->at(old_index)) != old_method) { 3811 ++old_index; 3812 } 3813 3814 if (MethodComparator::methods_EMCP(old_method, new_method)) { 3815 // The EMCP definition from JSR-163 requires the bytecodes to be 3816 // the same with the exception of constant pool indices which may 3817 // differ. However, the constants referred to by those indices 3818 // must be the same. 3819 // 3820 // We use methods_EMCP() for comparison since constant pool 3821 // merging can remove duplicate constant pool entries that were 3822 // present in the old method and removed from the rewritten new 3823 // method. A faster binary comparison function would consider the 3824 // old and new methods to be different when they are actually 3825 // EMCP. 3826 // 3827 // The old and new methods are EMCP and you would think that we 3828 // could get rid of one of them here and now and save some space. 3829 // However, the concept of EMCP only considers the bytecodes and 3830 // the constant pool entries in the comparison. Other things, 3831 // e.g., the line number table (LNT) or the local variable table 3832 // (LVT) don't count in the comparison. So the new (and EMCP) 3833 // method can have a new LNT that we need so we can't just 3834 // overwrite the new method with the old method. 3835 // 3836 // When this routine is called, we have already attached the new 3837 // methods to the_class so the old methods are effectively 3838 // overwritten. However, if an old method is still executing, 3839 // then the old method cannot be collected until sometime after 3840 // the old method call has returned. So the overwriting of old 3841 // methods by new methods will save us space except for those 3842 // (hopefully few) old methods that are still executing. 3843 // 3844 // A method refers to a ConstMethod* and this presents another 3845 // possible avenue to space savings. The ConstMethod* in the 3846 // new method contains possibly new attributes (LNT, LVT, etc). 3847 // At first glance, it seems possible to save space by replacing 3848 // the ConstMethod* in the old method with the ConstMethod* 3849 // from the new method. The old and new methods would share the 3850 // same ConstMethod* and we would save the space occupied by 3851 // the old ConstMethod*. However, the ConstMethod* contains 3852 // a back reference to the containing method. Sharing the 3853 // ConstMethod* between two methods could lead to confusion in 3854 // the code that uses the back reference. This would lead to 3855 // brittle code that could be broken in non-obvious ways now or 3856 // in the future. 3857 // 3858 // Another possibility is to copy the ConstMethod* from the new 3859 // method to the old method and then overwrite the new method with 3860 // the old method. Since the ConstMethod* contains the bytecodes 3861 // for the method embedded in the oop, this option would change 3862 // the bytecodes out from under any threads executing the old 3863 // method and make the thread's bcp invalid. Since EMCP requires 3864 // that the bytecodes be the same modulo constant pool indices, it 3865 // is straight forward to compute the correct new bcp in the new 3866 // ConstMethod* from the old bcp in the old ConstMethod*. The 3867 // time consuming part would be searching all the frames in all 3868 // of the threads to find all of the calls to the old method. 3869 // 3870 // It looks like we will have to live with the limited savings 3871 // that we get from effectively overwriting the old methods 3872 // when the new methods are attached to the_class. 3873 3874 // Count number of methods that are EMCP. The method will be marked 3875 // old but not obsolete if it is EMCP. 3876 emcp_method_count++; 3877 3878 // An EMCP method is _not_ obsolete. An obsolete method has a 3879 // different jmethodID than the current method. An EMCP method 3880 // has the same jmethodID as the current method. Having the 3881 // same jmethodID for all EMCP versions of a method allows for 3882 // a consistent view of the EMCP methods regardless of which 3883 // EMCP method you happen to have in hand. For example, a 3884 // breakpoint set in one EMCP method will work for all EMCP 3885 // versions of the method including the current one. 3886 } else { 3887 // mark obsolete methods as such 3888 old_method->set_is_obsolete(); 3889 obsolete_count++; 3890 3891 // obsolete methods need a unique idnum so they become new entries in 3892 // the jmethodID cache in InstanceKlass 3893 assert(old_method->method_idnum() == new_method->method_idnum(), "must match"); 3894 u2 num = InstanceKlass::cast(_the_class)->next_method_idnum(); 3895 if (num != ConstMethod::UNSET_IDNUM) { 3896 old_method->set_method_idnum(num); 3897 } 3898 3899 // With tracing we try not to "yack" too much. The position of 3900 // this trace assumes there are fewer obsolete methods than 3901 // EMCP methods. 3902 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) { 3903 ResourceMark rm; 3904 log_trace(redefine, class, obsolete, mark) 3905 ("mark %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string()); 3906 } 3907 } 3908 old_method->set_is_old(); 3909 } 3910 for (int i = 0; i < _deleted_methods_length; ++i) { 3911 Method* old_method = _deleted_methods[i]; 3912 3913 assert(!old_method->has_vtable_index(), 3914 "cannot delete methods with vtable entries");; 3915 3916 // Mark all deleted methods as old, obsolete and deleted 3917 old_method->set_is_deleted(); 3918 old_method->set_is_old(); 3919 old_method->set_is_obsolete(); 3920 ++obsolete_count; 3921 // With tracing we try not to "yack" too much. The position of 3922 // this trace assumes there are fewer obsolete methods than 3923 // EMCP methods. 3924 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) { 3925 ResourceMark rm; 3926 log_trace(redefine, class, obsolete, mark) 3927 ("mark deleted %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string()); 3928 } 3929 } 3930 assert((emcp_method_count + obsolete_count) == _old_methods->length(), 3931 "sanity check"); 3932 log_trace(redefine, class, obsolete, mark)("EMCP_cnt=%d, obsolete_cnt=%d", emcp_method_count, obsolete_count); 3933 return emcp_method_count; 3934 } 3935 3936 // This internal class transfers the native function registration from old methods 3937 // to new methods. It is designed to handle both the simple case of unchanged 3938 // native methods and the complex cases of native method prefixes being added and/or 3939 // removed. 3940 // It expects only to be used during the VM_RedefineClasses op (a safepoint). 3941 // 3942 // This class is used after the new methods have been installed in "the_class". 3943 // 3944 // So, for example, the following must be handled. Where 'm' is a method and 3945 // a number followed by an underscore is a prefix. 3946 // 3947 // Old Name New Name 3948 // Simple transfer to new method m -> m 3949 // Add prefix m -> 1_m 3950 // Remove prefix 1_m -> m 3951 // Simultaneous add of prefixes m -> 3_2_1_m 3952 // Simultaneous removal of prefixes 3_2_1_m -> m 3953 // Simultaneous add and remove 1_m -> 2_m 3954 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m 3955 // 3956 class TransferNativeFunctionRegistration { 3957 private: 3958 InstanceKlass* the_class; 3959 int prefix_count; 3960 char** prefixes; 3961 3962 // Recursively search the binary tree of possibly prefixed method names. 3963 // Iteration could be used if all agents were well behaved. Full tree walk is 3964 // more resilent to agents not cleaning up intermediate methods. 3965 // Branch at each depth in the binary tree is: 3966 // (1) without the prefix. 3967 // (2) with the prefix. 3968 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...) 3969 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len, 3970 Symbol* signature) { 3971 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len); 3972 if (name_symbol != NULL) { 3973 Method* method = the_class->lookup_method(name_symbol, signature); 3974 if (method != NULL) { 3975 // Even if prefixed, intermediate methods must exist. 3976 if (method->is_native()) { 3977 // Wahoo, we found a (possibly prefixed) version of the method, return it. 3978 return method; 3979 } 3980 if (depth < prefix_count) { 3981 // Try applying further prefixes (other than this one). 3982 method = search_prefix_name_space(depth+1, name_str, name_len, signature); 3983 if (method != NULL) { 3984 return method; // found 3985 } 3986 3987 // Try adding this prefix to the method name and see if it matches 3988 // another method name. 3989 char* prefix = prefixes[depth]; 3990 size_t prefix_len = strlen(prefix); 3991 size_t trial_len = name_len + prefix_len; 3992 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1); 3993 strcpy(trial_name_str, prefix); 3994 strcat(trial_name_str, name_str); 3995 method = search_prefix_name_space(depth+1, trial_name_str, trial_len, 3996 signature); 3997 if (method != NULL) { 3998 // If found along this branch, it was prefixed, mark as such 3999 method->set_is_prefixed_native(); 4000 return method; // found 4001 } 4002 } 4003 } 4004 } 4005 return NULL; // This whole branch bore nothing 4006 } 4007 4008 // Return the method name with old prefixes stripped away. 4009 char* method_name_without_prefixes(Method* method) { 4010 Symbol* name = method->name(); 4011 char* name_str = name->as_utf8(); 4012 4013 // Old prefixing may be defunct, strip prefixes, if any. 4014 for (int i = prefix_count-1; i >= 0; i--) { 4015 char* prefix = prefixes[i]; 4016 size_t prefix_len = strlen(prefix); 4017 if (strncmp(prefix, name_str, prefix_len) == 0) { 4018 name_str += prefix_len; 4019 } 4020 } 4021 return name_str; 4022 } 4023 4024 // Strip any prefixes off the old native method, then try to find a 4025 // (possibly prefixed) new native that matches it. 4026 Method* strip_and_search_for_new_native(Method* method) { 4027 ResourceMark rm; 4028 char* name_str = method_name_without_prefixes(method); 4029 return search_prefix_name_space(0, name_str, strlen(name_str), 4030 method->signature()); 4031 } 4032 4033 public: 4034 4035 // Construct a native method transfer processor for this class. 4036 TransferNativeFunctionRegistration(InstanceKlass* _the_class) { 4037 assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); 4038 4039 the_class = _the_class; 4040 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count); 4041 } 4042 4043 // Attempt to transfer any of the old or deleted methods that are native 4044 void transfer_registrations(Method** old_methods, int methods_length) { 4045 for (int j = 0; j < methods_length; j++) { 4046 Method* old_method = old_methods[j]; 4047 4048 if (old_method->is_native() && old_method->has_native_function()) { 4049 Method* new_method = strip_and_search_for_new_native(old_method); 4050 if (new_method != NULL) { 4051 // Actually set the native function in the new method. 4052 // Redefine does not send events (except CFLH), certainly not this 4053 // behind the scenes re-registration. 4054 new_method->set_native_function(old_method->native_function(), 4055 !Method::native_bind_event_is_interesting); 4056 } 4057 } 4058 } 4059 } 4060 }; 4061 4062 // Don't lose the association between a native method and its JNI function. 4063 void VM_RedefineClasses::transfer_old_native_function_registrations(InstanceKlass* the_class) { 4064 TransferNativeFunctionRegistration transfer(the_class); 4065 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length); 4066 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length); 4067 } 4068 4069 // Deoptimize all compiled code that depends on the classes redefined. 4070 // 4071 // If the can_redefine_classes capability is obtained in the onload 4072 // phase then the compiler has recorded all dependencies from startup. 4073 // In that case we need only deoptimize and throw away all compiled code 4074 // that depends on the class. 4075 // 4076 // If can_redefine_classes is obtained sometime after the onload 4077 // phase then the dependency information may be incomplete. In that case 4078 // the first call to RedefineClasses causes all compiled code to be 4079 // thrown away. As can_redefine_classes has been obtained then 4080 // all future compilations will record dependencies so second and 4081 // subsequent calls to RedefineClasses need only throw away code 4082 // that depends on the class. 4083 // 4084 4085 void VM_RedefineClasses::flush_dependent_code() { 4086 assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); 4087 4088 bool deopt_needed; 4089 4090 // This is the first redefinition, mark all the nmethods for deoptimization 4091 if (!JvmtiExport::all_dependencies_are_recorded()) { 4092 log_debug(redefine, class, nmethod)("Marked all nmethods for deopt"); 4093 CodeCache::mark_all_nmethods_for_evol_deoptimization(); 4094 deopt_needed = true; 4095 } else { 4096 int deopt = CodeCache::mark_dependents_for_evol_deoptimization(); 4097 log_debug(redefine, class, nmethod)("Marked %d dependent nmethods for deopt", deopt); 4098 deopt_needed = (deopt != 0); 4099 } 4100 4101 if (deopt_needed) { 4102 CodeCache::flush_evol_dependents(); 4103 } 4104 4105 // From now on we know that the dependency information is complete 4106 JvmtiExport::set_all_dependencies_are_recorded(true); 4107 } 4108 4109 void VM_RedefineClasses::compute_added_deleted_matching_methods() { 4110 Method* old_method; 4111 Method* new_method; 4112 4113 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 4114 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 4115 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length()); 4116 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 4117 4118 _matching_methods_length = 0; 4119 _deleted_methods_length = 0; 4120 _added_methods_length = 0; 4121 4122 int nj = 0; 4123 int oj = 0; 4124 while (true) { 4125 if (oj >= _old_methods->length()) { 4126 if (nj >= _new_methods->length()) { 4127 break; // we've looked at everything, done 4128 } 4129 // New method at the end 4130 new_method = _new_methods->at(nj); 4131 _added_methods[_added_methods_length++] = new_method; 4132 ++nj; 4133 } else if (nj >= _new_methods->length()) { 4134 // Old method, at the end, is deleted 4135 old_method = _old_methods->at(oj); 4136 _deleted_methods[_deleted_methods_length++] = old_method; 4137 ++oj; 4138 } else { 4139 old_method = _old_methods->at(oj); 4140 new_method = _new_methods->at(nj); 4141 if (old_method->name() == new_method->name()) { 4142 if (old_method->signature() == new_method->signature()) { 4143 _matching_old_methods[_matching_methods_length ] = old_method; 4144 _matching_new_methods[_matching_methods_length++] = new_method; 4145 ++nj; 4146 ++oj; 4147 } else { 4148 // added overloaded have already been moved to the end, 4149 // so this is a deleted overloaded method 4150 _deleted_methods[_deleted_methods_length++] = old_method; 4151 ++oj; 4152 } 4153 } else { // names don't match 4154 if (old_method->name()->fast_compare(new_method->name()) > 0) { 4155 // new method 4156 _added_methods[_added_methods_length++] = new_method; 4157 ++nj; 4158 } else { 4159 // deleted method 4160 _deleted_methods[_deleted_methods_length++] = old_method; 4161 ++oj; 4162 } 4163 } 4164 } 4165 } 4166 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity"); 4167 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity"); 4168 } 4169 4170 4171 void VM_RedefineClasses::swap_annotations(InstanceKlass* the_class, 4172 InstanceKlass* scratch_class) { 4173 // Swap annotation fields values 4174 Annotations* old_annotations = the_class->annotations(); 4175 the_class->set_annotations(scratch_class->annotations()); 4176 scratch_class->set_annotations(old_annotations); 4177 } 4178 4179 4180 // Install the redefinition of a class: 4181 // - house keeping (flushing breakpoints and caches, deoptimizing 4182 // dependent compiled code) 4183 // - replacing parts in the_class with parts from scratch_class 4184 // - adding a weak reference to track the obsolete but interesting 4185 // parts of the_class 4186 // - adjusting constant pool caches and vtables in other classes 4187 // that refer to methods in the_class. These adjustments use the 4188 // ClassLoaderDataGraph::classes_do() facility which only allows 4189 // a helper method to be specified. The interesting parameters 4190 // that we would like to pass to the helper method are saved in 4191 // static global fields in the VM operation. 4192 void VM_RedefineClasses::redefine_single_class(Thread* current, jclass the_jclass, 4193 InstanceKlass* scratch_class) { 4194 4195 HandleMark hm(current); // make sure handles from this call are freed 4196 4197 if (log_is_enabled(Info, redefine, class, timer)) { 4198 _timer_rsc_phase1.start(); 4199 } 4200 4201 InstanceKlass* the_class = get_ik(the_jclass); 4202 4203 // Set a flag to control and optimize adjusting method entries 4204 _has_redefined_Object |= the_class == vmClasses::Object_klass(); 4205 4206 // Remove all breakpoints in methods of this class 4207 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints(); 4208 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class); 4209 4210 _old_methods = the_class->methods(); 4211 _new_methods = scratch_class->methods(); 4212 _the_class = the_class; 4213 compute_added_deleted_matching_methods(); 4214 update_jmethod_ids(); 4215 4216 _any_class_has_resolved_methods = the_class->has_resolved_methods() || _any_class_has_resolved_methods; 4217 4218 // Attach new constant pool to the original klass. The original 4219 // klass still refers to the old constant pool (for now). 4220 scratch_class->constants()->set_pool_holder(the_class); 4221 4222 #if 0 4223 // In theory, with constant pool merging in place we should be able 4224 // to save space by using the new, merged constant pool in place of 4225 // the old constant pool(s). By "pool(s)" I mean the constant pool in 4226 // the klass version we are replacing now and any constant pool(s) in 4227 // previous versions of klass. Nice theory, doesn't work in practice. 4228 // When this code is enabled, even simple programs throw NullPointer 4229 // exceptions. I'm guessing that this is caused by some constant pool 4230 // cache difference between the new, merged constant pool and the 4231 // constant pool that was just being used by the klass. I'm keeping 4232 // this code around to archive the idea, but the code has to remain 4233 // disabled for now. 4234 4235 // Attach each old method to the new constant pool. This can be 4236 // done here since we are past the bytecode verification and 4237 // constant pool optimization phases. 4238 for (int i = _old_methods->length() - 1; i >= 0; i--) { 4239 Method* method = _old_methods->at(i); 4240 method->set_constants(scratch_class->constants()); 4241 } 4242 4243 // NOTE: this doesn't work because you can redefine the same class in two 4244 // threads, each getting their own constant pool data appended to the 4245 // original constant pool. In order for the new methods to work when they 4246 // become old methods, they need to keep their updated copy of the constant pool. 4247 4248 { 4249 // walk all previous versions of the klass 4250 InstanceKlass *ik = the_class; 4251 PreviousVersionWalker pvw(ik); 4252 do { 4253 ik = pvw.next_previous_version(); 4254 if (ik != NULL) { 4255 4256 // attach previous version of klass to the new constant pool 4257 ik->set_constants(scratch_class->constants()); 4258 4259 // Attach each method in the previous version of klass to the 4260 // new constant pool 4261 Array<Method*>* prev_methods = ik->methods(); 4262 for (int i = prev_methods->length() - 1; i >= 0; i--) { 4263 Method* method = prev_methods->at(i); 4264 method->set_constants(scratch_class->constants()); 4265 } 4266 } 4267 } while (ik != NULL); 4268 } 4269 #endif 4270 4271 // Replace methods and constantpool 4272 the_class->set_methods(_new_methods); 4273 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods, 4274 // and to be able to undo operation easily. 4275 4276 Array<int>* old_ordering = the_class->method_ordering(); 4277 the_class->set_method_ordering(scratch_class->method_ordering()); 4278 scratch_class->set_method_ordering(old_ordering); 4279 4280 ConstantPool* old_constants = the_class->constants(); 4281 the_class->set_constants(scratch_class->constants()); 4282 scratch_class->set_constants(old_constants); // See the previous comment. 4283 #if 0 4284 // We are swapping the guts of "the new class" with the guts of "the 4285 // class". Since the old constant pool has just been attached to "the 4286 // new class", it seems logical to set the pool holder in the old 4287 // constant pool also. However, doing this will change the observable 4288 // class hierarchy for any old methods that are still executing. A 4289 // method can query the identity of its "holder" and this query uses 4290 // the method's constant pool link to find the holder. The change in 4291 // holding class from "the class" to "the new class" can confuse 4292 // things. 4293 // 4294 // Setting the old constant pool's holder will also cause 4295 // verification done during vtable initialization below to fail. 4296 // During vtable initialization, the vtable's class is verified to be 4297 // a subtype of the method's holder. The vtable's class is "the 4298 // class" and the method's holder is gotten from the constant pool 4299 // link in the method itself. For "the class"'s directly implemented 4300 // methods, the method holder is "the class" itself (as gotten from 4301 // the new constant pool). The check works fine in this case. The 4302 // check also works fine for methods inherited from super classes. 4303 // 4304 // Miranda methods are a little more complicated. A miranda method is 4305 // provided by an interface when the class implementing the interface 4306 // does not provide its own method. These interfaces are implemented 4307 // internally as an InstanceKlass. These special instanceKlasses 4308 // share the constant pool of the class that "implements" the 4309 // interface. By sharing the constant pool, the method holder of a 4310 // miranda method is the class that "implements" the interface. In a 4311 // non-redefine situation, the subtype check works fine. However, if 4312 // the old constant pool's pool holder is modified, then the check 4313 // fails because there is no class hierarchy relationship between the 4314 // vtable's class and "the new class". 4315 4316 old_constants->set_pool_holder(scratch_class()); 4317 #endif 4318 4319 // track number of methods that are EMCP for add_previous_version() call below 4320 int emcp_method_count = check_methods_and_mark_as_obsolete(); 4321 transfer_old_native_function_registrations(the_class); 4322 4323 // The class file bytes from before any retransformable agents mucked 4324 // with them was cached on the scratch class, move to the_class. 4325 // Note: we still want to do this if nothing needed caching since it 4326 // should get cleared in the_class too. 4327 if (the_class->get_cached_class_file() == 0) { 4328 // the_class doesn't have a cache yet so copy it 4329 the_class->set_cached_class_file(scratch_class->get_cached_class_file()); 4330 } 4331 else if (scratch_class->get_cached_class_file() != 4332 the_class->get_cached_class_file()) { 4333 // The same class can be present twice in the scratch classes list or there 4334 // are multiple concurrent RetransformClasses calls on different threads. 4335 // In such cases we have to deallocate scratch_class cached_class_file. 4336 os::free(scratch_class->get_cached_class_file()); 4337 } 4338 4339 // NULL out in scratch class to not delete twice. The class to be redefined 4340 // always owns these bytes. 4341 scratch_class->set_cached_class_file(NULL); 4342 4343 // Replace inner_classes 4344 Array<u2>* old_inner_classes = the_class->inner_classes(); 4345 the_class->set_inner_classes(scratch_class->inner_classes()); 4346 scratch_class->set_inner_classes(old_inner_classes); 4347 4348 // Initialize the vtable and interface table after 4349 // methods have been rewritten 4350 // no exception should happen here since we explicitly 4351 // do not check loader constraints. 4352 // compare_and_normalize_class_versions has already checked: 4353 // - classloaders unchanged, signatures unchanged 4354 // - all instanceKlasses for redefined classes reused & contents updated 4355 the_class->vtable().initialize_vtable(); 4356 the_class->itable().initialize_itable(); 4357 4358 // Leave arrays of jmethodIDs and itable index cache unchanged 4359 4360 // Copy the "source file name" attribute from new class version 4361 the_class->set_source_file_name_index( 4362 scratch_class->source_file_name_index()); 4363 4364 // Copy the "source debug extension" attribute from new class version 4365 the_class->set_source_debug_extension( 4366 scratch_class->source_debug_extension(), 4367 scratch_class->source_debug_extension() == NULL ? 0 : 4368 (int)strlen(scratch_class->source_debug_extension())); 4369 4370 // Use of javac -g could be different in the old and the new 4371 if (scratch_class->access_flags().has_localvariable_table() != 4372 the_class->access_flags().has_localvariable_table()) { 4373 4374 AccessFlags flags = the_class->access_flags(); 4375 if (scratch_class->access_flags().has_localvariable_table()) { 4376 flags.set_has_localvariable_table(); 4377 } else { 4378 flags.clear_has_localvariable_table(); 4379 } 4380 the_class->set_access_flags(flags); 4381 } 4382 4383 swap_annotations(the_class, scratch_class); 4384 4385 // Replace minor version number of class file 4386 u2 old_minor_version = the_class->constants()->minor_version(); 4387 the_class->constants()->set_minor_version(scratch_class->constants()->minor_version()); 4388 scratch_class->constants()->set_minor_version(old_minor_version); 4389 4390 // Replace major version number of class file 4391 u2 old_major_version = the_class->constants()->major_version(); 4392 the_class->constants()->set_major_version(scratch_class->constants()->major_version()); 4393 scratch_class->constants()->set_major_version(old_major_version); 4394 4395 // Replace CP indexes for class and name+type of enclosing method 4396 u2 old_class_idx = the_class->enclosing_method_class_index(); 4397 u2 old_method_idx = the_class->enclosing_method_method_index(); 4398 the_class->set_enclosing_method_indices( 4399 scratch_class->enclosing_method_class_index(), 4400 scratch_class->enclosing_method_method_index()); 4401 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx); 4402 4403 the_class->set_has_been_redefined(); 4404 4405 // Scratch class is unloaded but still needs cleaning, and skipping for CDS. 4406 scratch_class->set_is_scratch_class(); 4407 4408 // keep track of previous versions of this class 4409 the_class->add_previous_version(scratch_class, emcp_method_count); 4410 4411 _timer_rsc_phase1.stop(); 4412 if (log_is_enabled(Info, redefine, class, timer)) { 4413 _timer_rsc_phase2.start(); 4414 } 4415 4416 if (the_class->oop_map_cache() != NULL) { 4417 // Flush references to any obsolete methods from the oop map cache 4418 // so that obsolete methods are not pinned. 4419 the_class->oop_map_cache()->flush_obsolete_entries(); 4420 } 4421 4422 increment_class_counter(the_class); 4423 4424 if (EventClassRedefinition::is_enabled()) { 4425 EventClassRedefinition event; 4426 event.set_classModificationCount(java_lang_Class::classRedefinedCount(the_class->java_mirror())); 4427 event.set_redefinedClass(the_class); 4428 event.set_redefinitionId(_id); 4429 event.commit(); 4430 } 4431 4432 { 4433 ResourceMark rm(current); 4434 // increment the classRedefinedCount field in the_class and in any 4435 // direct and indirect subclasses of the_class 4436 log_info(redefine, class, load) 4437 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)", 4438 the_class->external_name(), java_lang_Class::classRedefinedCount(the_class->java_mirror()), os::available_memory() >> 10); 4439 Events::log_redefinition(current, "redefined class name=%s, count=%d", 4440 the_class->external_name(), 4441 java_lang_Class::classRedefinedCount(the_class->java_mirror())); 4442 4443 } 4444 _timer_rsc_phase2.stop(); 4445 4446 } // end redefine_single_class() 4447 4448 4449 // Increment the classRedefinedCount field in the specific InstanceKlass 4450 // and in all direct and indirect subclasses. 4451 void VM_RedefineClasses::increment_class_counter(InstanceKlass* ik) { 4452 for (ClassHierarchyIterator iter(ik); !iter.done(); iter.next()) { 4453 // Only update instanceKlasses 4454 Klass* sub = iter.klass(); 4455 if (sub->is_instance_klass()) { 4456 oop class_mirror = InstanceKlass::cast(sub)->java_mirror(); 4457 Klass* class_oop = java_lang_Class::as_Klass(class_mirror); 4458 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1; 4459 java_lang_Class::set_classRedefinedCount(class_mirror, new_count); 4460 4461 if (class_oop != _the_class) { 4462 // _the_class count is printed at end of redefine_single_class() 4463 log_debug(redefine, class, subclass)("updated count in subclass=%s to %d", ik->external_name(), new_count); 4464 } 4465 } 4466 } 4467 } 4468 4469 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) { 4470 bool no_old_methods = true; // be optimistic 4471 4472 // Both array and instance classes have vtables. 4473 // a vtable should never contain old or obsolete methods 4474 ResourceMark rm(_thread); 4475 if (k->vtable_length() > 0 && 4476 !k->vtable().check_no_old_or_obsolete_entries()) { 4477 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 4478 log_trace(redefine, class, obsolete, metadata) 4479 ("klassVtable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s", 4480 k->signature_name()); 4481 k->vtable().dump_vtable(); 4482 } 4483 no_old_methods = false; 4484 } 4485 4486 if (k->is_instance_klass()) { 4487 HandleMark hm(_thread); 4488 InstanceKlass *ik = InstanceKlass::cast(k); 4489 4490 // an itable should never contain old or obsolete methods 4491 if (ik->itable_length() > 0 && 4492 !ik->itable().check_no_old_or_obsolete_entries()) { 4493 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 4494 log_trace(redefine, class, obsolete, metadata) 4495 ("klassItable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s", 4496 ik->signature_name()); 4497 ik->itable().dump_itable(); 4498 } 4499 no_old_methods = false; 4500 } 4501 4502 // the constant pool cache should never contain non-deleted old or obsolete methods 4503 if (ik->constants() != NULL && 4504 ik->constants()->cache() != NULL && 4505 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) { 4506 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 4507 log_trace(redefine, class, obsolete, metadata) 4508 ("cp-cache::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s", 4509 ik->signature_name()); 4510 ik->constants()->cache()->dump_cache(); 4511 } 4512 no_old_methods = false; 4513 } 4514 } 4515 4516 // print and fail guarantee if old methods are found. 4517 if (!no_old_methods) { 4518 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 4519 dump_methods(); 4520 } else { 4521 log_trace(redefine, class)("Use the '-Xlog:redefine+class*:' option " 4522 "to see more info about the following guarantee() failure."); 4523 } 4524 guarantee(false, "OLD and/or OBSOLETE method(s) found"); 4525 } 4526 } 4527 4528 u8 VM_RedefineClasses::next_id() { 4529 while (true) { 4530 u8 id = _id_counter; 4531 u8 next_id = id + 1; 4532 u8 result = Atomic::cmpxchg(&_id_counter, id, next_id); 4533 if (result == id) { 4534 return next_id; 4535 } 4536 } 4537 } 4538 4539 void VM_RedefineClasses::dump_methods() { 4540 int j; 4541 log_trace(redefine, class, dump)("_old_methods --"); 4542 for (j = 0; j < _old_methods->length(); ++j) { 4543 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4544 Method* m = _old_methods->at(j); 4545 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4546 m->access_flags().print_on(&log_stream); 4547 log_stream.print(" -- "); 4548 m->print_name(&log_stream); 4549 log_stream.cr(); 4550 } 4551 log_trace(redefine, class, dump)("_new_methods --"); 4552 for (j = 0; j < _new_methods->length(); ++j) { 4553 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4554 Method* m = _new_methods->at(j); 4555 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4556 m->access_flags().print_on(&log_stream); 4557 log_stream.print(" -- "); 4558 m->print_name(&log_stream); 4559 log_stream.cr(); 4560 } 4561 log_trace(redefine, class, dump)("_matching_methods --"); 4562 for (j = 0; j < _matching_methods_length; ++j) { 4563 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4564 Method* m = _matching_old_methods[j]; 4565 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4566 m->access_flags().print_on(&log_stream); 4567 log_stream.print(" -- "); 4568 m->print_name(); 4569 log_stream.cr(); 4570 4571 m = _matching_new_methods[j]; 4572 log_stream.print(" (%5d) ", m->vtable_index()); 4573 m->access_flags().print_on(&log_stream); 4574 log_stream.cr(); 4575 } 4576 log_trace(redefine, class, dump)("_deleted_methods --"); 4577 for (j = 0; j < _deleted_methods_length; ++j) { 4578 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4579 Method* m = _deleted_methods[j]; 4580 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4581 m->access_flags().print_on(&log_stream); 4582 log_stream.print(" -- "); 4583 m->print_name(&log_stream); 4584 log_stream.cr(); 4585 } 4586 log_trace(redefine, class, dump)("_added_methods --"); 4587 for (j = 0; j < _added_methods_length; ++j) { 4588 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4589 Method* m = _added_methods[j]; 4590 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4591 m->access_flags().print_on(&log_stream); 4592 log_stream.print(" -- "); 4593 m->print_name(&log_stream); 4594 log_stream.cr(); 4595 } 4596 } 4597 4598 void VM_RedefineClasses::print_on_error(outputStream* st) const { 4599 VM_Operation::print_on_error(st); 4600 if (_the_class != NULL) { 4601 ResourceMark rm; 4602 st->print_cr(", redefining class %s", _the_class->external_name()); 4603 } 4604 }