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 here 602 case JVM_CONSTANT_UnresolvedClassInError: // fall through 603 604 default: 605 { 606 // leave a breadcrumb 607 jbyte bad_value = scratch_cp->tag_at(scratch_i).value(); 608 ShouldNotReachHere(); 609 } break; 610 } // end switch tag value 611 } // end append_entry() 612 613 614 int VM_RedefineClasses::find_or_append_indirect_entry(const constantPoolHandle& scratch_cp, 615 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) { 616 617 int new_ref_i = ref_i; 618 bool match = (ref_i < *merge_cp_length_p) && 619 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i); 620 621 if (!match) { 622 // forward reference in *merge_cp_p or not a direct match 623 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p); 624 if (found_i != 0) { 625 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree"); 626 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry. 627 new_ref_i = found_i; 628 map_index(scratch_cp, ref_i, found_i); 629 } else { 630 // no match found so we have to append this entry to *merge_cp_p 631 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p); 632 // The above call to append_entry() can only append one entry 633 // so the post call query of *merge_cp_length_p is only for 634 // the sake of consistency. 635 new_ref_i = *merge_cp_length_p - 1; 636 } 637 } 638 639 return new_ref_i; 640 } // end find_or_append_indirect_entry() 641 642 643 // Append a bootstrap specifier into the merge_cp operands that is semantically equal 644 // to the scratch_cp operands bootstrap specifier passed by the old_bs_i index. 645 // Recursively append new merge_cp entries referenced by the new bootstrap specifier. 646 void VM_RedefineClasses::append_operand(const constantPoolHandle& scratch_cp, int old_bs_i, 647 constantPoolHandle *merge_cp_p, int *merge_cp_length_p) { 648 649 int old_ref_i = scratch_cp->operand_bootstrap_method_ref_index_at(old_bs_i); 650 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p, 651 merge_cp_length_p); 652 if (new_ref_i != old_ref_i) { 653 log_trace(redefine, class, constantpool) 654 ("operands entry@%d bootstrap method ref_index change: %d to %d", _operands_cur_length, old_ref_i, new_ref_i); 655 } 656 657 Array<u2>* merge_ops = (*merge_cp_p)->operands(); 658 int new_bs_i = _operands_cur_length; 659 // We have _operands_cur_length == 0 when the merge_cp operands is empty yet. 660 // However, the operand_offset_at(0) was set in the extend_operands() call. 661 int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0) 662 : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1); 663 int argc = scratch_cp->operand_argument_count_at(old_bs_i); 664 665 ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base); 666 merge_ops->at_put(new_base++, new_ref_i); 667 merge_ops->at_put(new_base++, argc); 668 669 for (int i = 0; i < argc; i++) { 670 int old_arg_ref_i = scratch_cp->operand_argument_index_at(old_bs_i, i); 671 int new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p, 672 merge_cp_length_p); 673 merge_ops->at_put(new_base++, new_arg_ref_i); 674 if (new_arg_ref_i != old_arg_ref_i) { 675 log_trace(redefine, class, constantpool) 676 ("operands entry@%d bootstrap method argument ref_index change: %d to %d", 677 _operands_cur_length, old_arg_ref_i, new_arg_ref_i); 678 } 679 } 680 if (old_bs_i != _operands_cur_length) { 681 // The bootstrap specifier in *merge_cp_p is at a different index than 682 // that in scratch_cp so we need to map the index values. 683 map_operand_index(old_bs_i, new_bs_i); 684 } 685 _operands_cur_length++; 686 } // end append_operand() 687 688 689 int VM_RedefineClasses::find_or_append_operand(const constantPoolHandle& scratch_cp, 690 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) { 691 692 int new_bs_i = old_bs_i; // bootstrap specifier index 693 bool match = (old_bs_i < _operands_cur_length) && 694 scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i); 695 696 if (!match) { 697 // forward reference in *merge_cp_p or not a direct match 698 int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p, 699 _operands_cur_length); 700 if (found_i != -1) { 701 guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree"); 702 // found a matching operand somewhere else in *merge_cp_p so just need a mapping 703 new_bs_i = found_i; 704 map_operand_index(old_bs_i, found_i); 705 } else { 706 // no match found so we have to append this bootstrap specifier to *merge_cp_p 707 append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p); 708 new_bs_i = _operands_cur_length - 1; 709 } 710 } 711 return new_bs_i; 712 } // end find_or_append_operand() 713 714 715 void VM_RedefineClasses::finalize_operands_merge(const constantPoolHandle& merge_cp, TRAPS) { 716 if (merge_cp->operands() == NULL) { 717 return; 718 } 719 // Shrink the merge_cp operands 720 merge_cp->shrink_operands(_operands_cur_length, CHECK); 721 722 if (log_is_enabled(Trace, redefine, class, constantpool)) { 723 // don't want to loop unless we are tracing 724 int count = 0; 725 for (int i = 1; i < _operands_index_map_p->length(); i++) { 726 int value = _operands_index_map_p->at(i); 727 if (value != -1) { 728 log_trace(redefine, class, constantpool)("operands_index_map[%d]: old=%d new=%d", count, i, value); 729 count++; 730 } 731 } 732 } 733 // Clean-up 734 _operands_index_map_p = NULL; 735 _operands_cur_length = 0; 736 _operands_index_map_count = 0; 737 } // end finalize_operands_merge() 738 739 // Symbol* comparator for qsort 740 // The caller must have an active ResourceMark. 741 static int symcmp(const void* a, const void* b) { 742 char* astr = (*(Symbol**)a)->as_C_string(); 743 char* bstr = (*(Symbol**)b)->as_C_string(); 744 return strcmp(astr, bstr); 745 } 746 747 // The caller must have an active ResourceMark. 748 static jvmtiError check_attribute_arrays(const char* attr_name, 749 InstanceKlass* the_class, InstanceKlass* scratch_class, 750 Array<u2>* the_array, Array<u2>* scr_array) { 751 bool the_array_exists = the_array != Universe::the_empty_short_array(); 752 bool scr_array_exists = scr_array != Universe::the_empty_short_array(); 753 754 int array_len = the_array->length(); 755 if (the_array_exists && scr_array_exists) { 756 if (array_len != scr_array->length()) { 757 log_trace(redefine, class) 758 ("redefined class %s attribute change error: %s len=%d changed to len=%d", 759 the_class->external_name(), attr_name, array_len, scr_array->length()); 760 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 761 } 762 763 // The order of entries in the attribute array is not specified so we 764 // have to explicitly check for the same contents. We do this by copying 765 // the referenced symbols into their own arrays, sorting them and then 766 // comparing each element pair. 767 768 Symbol** the_syms = NEW_RESOURCE_ARRAY_RETURN_NULL(Symbol*, array_len); 769 Symbol** scr_syms = NEW_RESOURCE_ARRAY_RETURN_NULL(Symbol*, array_len); 770 771 if (the_syms == NULL || scr_syms == NULL) { 772 return JVMTI_ERROR_OUT_OF_MEMORY; 773 } 774 775 for (int i = 0; i < array_len; i++) { 776 int the_cp_index = the_array->at(i); 777 int scr_cp_index = scr_array->at(i); 778 the_syms[i] = the_class->constants()->klass_name_at(the_cp_index); 779 scr_syms[i] = scratch_class->constants()->klass_name_at(scr_cp_index); 780 } 781 782 qsort(the_syms, array_len, sizeof(Symbol*), symcmp); 783 qsort(scr_syms, array_len, sizeof(Symbol*), symcmp); 784 785 for (int i = 0; i < array_len; i++) { 786 if (the_syms[i] != scr_syms[i]) { 787 log_info(redefine, class) 788 ("redefined class %s attribute change error: %s[%d]: %s changed to %s", 789 the_class->external_name(), attr_name, i, 790 the_syms[i]->as_C_string(), scr_syms[i]->as_C_string()); 791 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 792 } 793 } 794 } else if (the_array_exists ^ scr_array_exists) { 795 const char* action_str = (the_array_exists) ? "removed" : "added"; 796 log_info(redefine, class) 797 ("redefined class %s attribute change error: %s attribute %s", 798 the_class->external_name(), attr_name, action_str); 799 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 800 } 801 return JVMTI_ERROR_NONE; 802 } 803 804 static jvmtiError check_nest_attributes(InstanceKlass* the_class, 805 InstanceKlass* scratch_class) { 806 // Check whether the class NestHost attribute has been changed. 807 Thread* thread = Thread::current(); 808 ResourceMark rm(thread); 809 u2 the_nest_host_idx = the_class->nest_host_index(); 810 u2 scr_nest_host_idx = scratch_class->nest_host_index(); 811 812 if (the_nest_host_idx != 0 && scr_nest_host_idx != 0) { 813 Symbol* the_sym = the_class->constants()->klass_name_at(the_nest_host_idx); 814 Symbol* scr_sym = scratch_class->constants()->klass_name_at(scr_nest_host_idx); 815 if (the_sym != scr_sym) { 816 log_info(redefine, class, nestmates) 817 ("redefined class %s attribute change error: NestHost class: %s replaced with: %s", 818 the_class->external_name(), the_sym->as_C_string(), scr_sym->as_C_string()); 819 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 820 } 821 } else if ((the_nest_host_idx == 0) ^ (scr_nest_host_idx == 0)) { 822 const char* action_str = (the_nest_host_idx != 0) ? "removed" : "added"; 823 log_info(redefine, class, nestmates) 824 ("redefined class %s attribute change error: NestHost attribute %s", 825 the_class->external_name(), action_str); 826 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 827 } 828 829 // Check whether the class NestMembers attribute has been changed. 830 return check_attribute_arrays("NestMembers", 831 the_class, scratch_class, 832 the_class->nest_members(), 833 scratch_class->nest_members()); 834 } 835 836 // Return an error status if the class Record attribute was changed. 837 static jvmtiError check_record_attribute(InstanceKlass* the_class, InstanceKlass* scratch_class) { 838 // Get lists of record components. 839 Array<RecordComponent*>* the_record = the_class->record_components(); 840 Array<RecordComponent*>* scr_record = scratch_class->record_components(); 841 bool the_record_exists = the_record != NULL; 842 bool scr_record_exists = scr_record != NULL; 843 844 if (the_record_exists && scr_record_exists) { 845 int the_num_components = the_record->length(); 846 int scr_num_components = scr_record->length(); 847 if (the_num_components != scr_num_components) { 848 log_info(redefine, class, record) 849 ("redefined class %s attribute change error: Record num_components=%d changed to num_components=%d", 850 the_class->external_name(), the_num_components, scr_num_components); 851 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 852 } 853 854 // Compare each field in each record component. 855 ConstantPool* the_cp = the_class->constants(); 856 ConstantPool* scr_cp = scratch_class->constants(); 857 for (int x = 0; x < the_num_components; x++) { 858 RecordComponent* the_component = the_record->at(x); 859 RecordComponent* scr_component = scr_record->at(x); 860 const Symbol* const the_name = the_cp->symbol_at(the_component->name_index()); 861 const Symbol* const scr_name = scr_cp->symbol_at(scr_component->name_index()); 862 const Symbol* const the_descr = the_cp->symbol_at(the_component->descriptor_index()); 863 const Symbol* const scr_descr = scr_cp->symbol_at(scr_component->descriptor_index()); 864 if (the_name != scr_name || the_descr != scr_descr) { 865 log_info(redefine, class, record) 866 ("redefined class %s attribute change error: Record name_index, descriptor_index, and/or attributes_count changed", 867 the_class->external_name()); 868 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 869 } 870 871 int the_gen_sig = the_component->generic_signature_index(); 872 int scr_gen_sig = scr_component->generic_signature_index(); 873 const Symbol* const the_gen_sig_sym = (the_gen_sig == 0 ? NULL : 874 the_cp->symbol_at(the_component->generic_signature_index())); 875 const Symbol* const scr_gen_sig_sym = (scr_gen_sig == 0 ? NULL : 876 scr_cp->symbol_at(scr_component->generic_signature_index())); 877 if (the_gen_sig_sym != scr_gen_sig_sym) { 878 log_info(redefine, class, record) 879 ("redefined class %s attribute change error: Record generic_signature attribute changed", 880 the_class->external_name()); 881 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 882 } 883 884 // It's okay if a record component's annotations were changed. 885 } 886 887 } else if (the_record_exists ^ scr_record_exists) { 888 const char* action_str = (the_record_exists) ? "removed" : "added"; 889 log_info(redefine, class, record) 890 ("redefined class %s attribute change error: Record attribute %s", 891 the_class->external_name(), action_str); 892 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED; 893 } 894 895 return JVMTI_ERROR_NONE; 896 } 897 898 899 static jvmtiError check_permitted_subclasses_attribute(InstanceKlass* the_class, 900 InstanceKlass* scratch_class) { 901 Thread* thread = Thread::current(); 902 ResourceMark rm(thread); 903 904 // Check whether the class PermittedSubclasses attribute has been changed. 905 return check_attribute_arrays("PermittedSubclasses", 906 the_class, scratch_class, 907 the_class->permitted_subclasses(), 908 scratch_class->permitted_subclasses()); 909 } 910 911 static jvmtiError check_preload_attribute(InstanceKlass* the_class, 912 InstanceKlass* scratch_class) { 913 Thread* thread = Thread::current(); 914 ResourceMark rm(thread); 915 916 // Check whether the class Preload attribute has been changed. 917 return check_attribute_arrays("Preload", 918 the_class, scratch_class, 919 the_class->preload_classes(), 920 scratch_class->preload_classes()); 921 } 922 923 static bool can_add_or_delete(Method* m) { 924 // Compatibility mode 925 return (AllowRedefinitionToAddDeleteMethods && 926 (m->is_private() && (m->is_static() || m->is_final()))); 927 } 928 929 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions( 930 InstanceKlass* the_class, 931 InstanceKlass* scratch_class) { 932 int i; 933 934 // Check superclasses, or rather their names, since superclasses themselves can be 935 // requested to replace. 936 // Check for NULL superclass first since this might be java.lang.Object 937 if (the_class->super() != scratch_class->super() && 938 (the_class->super() == NULL || scratch_class->super() == NULL || 939 the_class->super()->name() != 940 scratch_class->super()->name())) { 941 log_info(redefine, class, normalize) 942 ("redefined class %s superclass change error: superclass changed from %s to %s.", 943 the_class->external_name(), 944 the_class->super() == NULL ? "NULL" : the_class->super()->external_name(), 945 scratch_class->super() == NULL ? "NULL" : scratch_class->super()->external_name()); 946 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 947 } 948 949 // Check if the number, names and order of directly implemented interfaces are the same. 950 // I think in principle we should just check if the sets of names of directly implemented 951 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the 952 // .java file, also changes in .class file) should not matter. However, comparing sets is 953 // technically a bit more difficult, and, more importantly, I am not sure at present that the 954 // order of interfaces does not matter on the implementation level, i.e. that the VM does not 955 // rely on it somewhere. 956 Array<InstanceKlass*>* k_interfaces = the_class->local_interfaces(); 957 Array<InstanceKlass*>* k_new_interfaces = scratch_class->local_interfaces(); 958 int n_intfs = k_interfaces->length(); 959 if (n_intfs != k_new_interfaces->length()) { 960 log_info(redefine, class, normalize) 961 ("redefined class %s interfaces change error: number of implemented interfaces changed from %d to %d.", 962 the_class->external_name(), n_intfs, k_new_interfaces->length()); 963 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 964 } 965 for (i = 0; i < n_intfs; i++) { 966 if (k_interfaces->at(i)->name() != 967 k_new_interfaces->at(i)->name()) { 968 log_info(redefine, class, normalize) 969 ("redefined class %s interfaces change error: interface changed from %s to %s.", 970 the_class->external_name(), 971 k_interfaces->at(i)->external_name(), k_new_interfaces->at(i)->external_name()); 972 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 973 } 974 } 975 976 // Check whether class is in the error init state. 977 if (the_class->is_in_error_state()) { 978 log_info(redefine, class, normalize) 979 ("redefined class %s is in error init state.", the_class->external_name()); 980 // TBD #5057930: special error code is needed in 1.6 981 return JVMTI_ERROR_INVALID_CLASS; 982 } 983 984 // Check whether the nest-related attributes have been changed. 985 jvmtiError err = check_nest_attributes(the_class, scratch_class); 986 if (err != JVMTI_ERROR_NONE) { 987 return err; 988 } 989 990 // Check whether the Record attribute has been changed. 991 err = check_record_attribute(the_class, scratch_class); 992 if (err != JVMTI_ERROR_NONE) { 993 return err; 994 } 995 996 // Check whether the PermittedSubclasses attribute has been changed. 997 err = check_permitted_subclasses_attribute(the_class, scratch_class); 998 if (err != JVMTI_ERROR_NONE) { 999 return err; 1000 } 1001 1002 // Check whether the Preload attribute has been changed. 1003 err = check_preload_attribute(the_class, scratch_class); 1004 if (err != JVMTI_ERROR_NONE) { 1005 return err; 1006 } 1007 1008 // Check whether class modifiers are the same. 1009 jushort old_flags = (jushort) the_class->access_flags().get_flags(); 1010 jushort new_flags = (jushort) scratch_class->access_flags().get_flags(); 1011 if (old_flags != new_flags) { 1012 log_info(redefine, class, normalize) 1013 ("redefined class %s modifiers change error: modifiers changed from %d to %d.", 1014 the_class->external_name(), old_flags, new_flags); 1015 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED; 1016 } 1017 1018 // Check if the number, names, types and order of fields declared in these classes 1019 // are the same. 1020 JavaFieldStream old_fs(the_class); 1021 JavaFieldStream new_fs(scratch_class); 1022 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) { 1023 // name and signature 1024 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index()); 1025 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index()); 1026 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index()); 1027 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index()); 1028 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) { 1029 log_info(redefine, class, normalize) 1030 ("redefined class %s fields change error: field %s %s changed to %s %s.", 1031 the_class->external_name(), 1032 sig_sym1->as_C_string(), name_sym1->as_C_string(), 1033 sig_sym2->as_C_string(), name_sym2->as_C_string()); 1034 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 1035 } 1036 // offset 1037 if (old_fs.offset() != new_fs.offset()) { 1038 log_info(redefine, class, normalize) 1039 ("redefined class %s field %s change error: offset changed from %d to %d.", 1040 the_class->external_name(), name_sym2->as_C_string(), old_fs.offset(), new_fs.offset()); 1041 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 1042 } 1043 // access 1044 old_flags = old_fs.access_flags().as_short(); 1045 new_flags = new_fs.access_flags().as_short(); 1046 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) { 1047 log_info(redefine, class, normalize) 1048 ("redefined class %s field %s change error: modifiers changed from %d to %d.", 1049 the_class->external_name(), name_sym2->as_C_string(), old_flags, new_flags); 1050 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 1051 } 1052 } 1053 1054 // If both streams aren't done then we have a differing number of 1055 // fields. 1056 if (!old_fs.done() || !new_fs.done()) { 1057 const char* action = old_fs.done() ? "added" : "deleted"; 1058 log_info(redefine, class, normalize) 1059 ("redefined class %s fields change error: some fields were %s.", 1060 the_class->external_name(), action); 1061 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 1062 } 1063 1064 // Do a parallel walk through the old and new methods. Detect 1065 // cases where they match (exist in both), have been added in 1066 // the new methods, or have been deleted (exist only in the 1067 // old methods). The class file parser places methods in order 1068 // by method name, but does not order overloaded methods by 1069 // signature. In order to determine what fate befell the methods, 1070 // this code places the overloaded new methods that have matching 1071 // old methods in the same order as the old methods and places 1072 // new overloaded methods at the end of overloaded methods of 1073 // that name. The code for this order normalization is adapted 1074 // from the algorithm used in InstanceKlass::find_method(). 1075 // Since we are swapping out of order entries as we find them, 1076 // we only have to search forward through the overloaded methods. 1077 // Methods which are added and have the same name as an existing 1078 // method (but different signature) will be put at the end of 1079 // the methods with that name, and the name mismatch code will 1080 // handle them. 1081 Array<Method*>* k_old_methods(the_class->methods()); 1082 Array<Method*>* k_new_methods(scratch_class->methods()); 1083 int n_old_methods = k_old_methods->length(); 1084 int n_new_methods = k_new_methods->length(); 1085 Thread* thread = Thread::current(); 1086 1087 int ni = 0; 1088 int oi = 0; 1089 while (true) { 1090 Method* k_old_method; 1091 Method* k_new_method; 1092 enum { matched, added, deleted, undetermined } method_was = undetermined; 1093 1094 if (oi >= n_old_methods) { 1095 if (ni >= n_new_methods) { 1096 break; // we've looked at everything, done 1097 } 1098 // New method at the end 1099 k_new_method = k_new_methods->at(ni); 1100 method_was = added; 1101 } else if (ni >= n_new_methods) { 1102 // Old method, at the end, is deleted 1103 k_old_method = k_old_methods->at(oi); 1104 method_was = deleted; 1105 } else { 1106 // There are more methods in both the old and new lists 1107 k_old_method = k_old_methods->at(oi); 1108 k_new_method = k_new_methods->at(ni); 1109 if (k_old_method->name() != k_new_method->name()) { 1110 // Methods are sorted by method name, so a mismatch means added 1111 // or deleted 1112 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) { 1113 method_was = added; 1114 } else { 1115 method_was = deleted; 1116 } 1117 } else if (k_old_method->signature() == k_new_method->signature()) { 1118 // Both the name and signature match 1119 method_was = matched; 1120 } else { 1121 // The name matches, but the signature doesn't, which means we have to 1122 // search forward through the new overloaded methods. 1123 int nj; // outside the loop for post-loop check 1124 for (nj = ni + 1; nj < n_new_methods; nj++) { 1125 Method* m = k_new_methods->at(nj); 1126 if (k_old_method->name() != m->name()) { 1127 // reached another method name so no more overloaded methods 1128 method_was = deleted; 1129 break; 1130 } 1131 if (k_old_method->signature() == m->signature()) { 1132 // found a match so swap the methods 1133 k_new_methods->at_put(ni, m); 1134 k_new_methods->at_put(nj, k_new_method); 1135 k_new_method = m; 1136 method_was = matched; 1137 break; 1138 } 1139 } 1140 1141 if (nj >= n_new_methods) { 1142 // reached the end without a match; so method was deleted 1143 method_was = deleted; 1144 } 1145 } 1146 } 1147 1148 switch (method_was) { 1149 case matched: 1150 // methods match, be sure modifiers do too 1151 old_flags = (jushort) k_old_method->access_flags().get_flags(); 1152 new_flags = (jushort) k_new_method->access_flags().get_flags(); 1153 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) { 1154 log_info(redefine, class, normalize) 1155 ("redefined class %s method %s modifiers error: modifiers changed from %d to %d", 1156 the_class->external_name(), k_old_method->name_and_sig_as_C_string(), old_flags, new_flags); 1157 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED; 1158 } 1159 { 1160 u2 new_num = k_new_method->method_idnum(); 1161 u2 old_num = k_old_method->method_idnum(); 1162 if (new_num != old_num) { 1163 Method* idnum_owner = scratch_class->method_with_idnum(old_num); 1164 if (idnum_owner != NULL) { 1165 // There is already a method assigned this idnum -- switch them 1166 // Take current and original idnum from the new_method 1167 idnum_owner->set_method_idnum(new_num); 1168 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum()); 1169 } 1170 // Take current and original idnum from the old_method 1171 k_new_method->set_method_idnum(old_num); 1172 k_new_method->set_orig_method_idnum(k_old_method->orig_method_idnum()); 1173 if (thread->has_pending_exception()) { 1174 return JVMTI_ERROR_OUT_OF_MEMORY; 1175 } 1176 } 1177 } 1178 log_trace(redefine, class, normalize) 1179 ("Method matched: new: %s [%d] == old: %s [%d]", 1180 k_new_method->name_and_sig_as_C_string(), ni, k_old_method->name_and_sig_as_C_string(), oi); 1181 // advance to next pair of methods 1182 ++oi; 1183 ++ni; 1184 break; 1185 case added: 1186 // method added, see if it is OK 1187 if (!can_add_or_delete(k_new_method)) { 1188 log_info(redefine, class, normalize) 1189 ("redefined class %s methods error: added method: %s [%d]", 1190 the_class->external_name(), k_new_method->name_and_sig_as_C_string(), ni); 1191 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED; 1192 } 1193 { 1194 u2 num = the_class->next_method_idnum(); 1195 if (num == ConstMethod::UNSET_IDNUM) { 1196 // cannot add any more methods 1197 log_info(redefine, class, normalize) 1198 ("redefined class %s methods error: can't create ID for new method %s [%d]", 1199 the_class->external_name(), k_new_method->name_and_sig_as_C_string(), ni); 1200 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED; 1201 } 1202 u2 new_num = k_new_method->method_idnum(); 1203 Method* idnum_owner = scratch_class->method_with_idnum(num); 1204 if (idnum_owner != NULL) { 1205 // There is already a method assigned this idnum -- switch them 1206 // Take current and original idnum from the new_method 1207 idnum_owner->set_method_idnum(new_num); 1208 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum()); 1209 } 1210 k_new_method->set_method_idnum(num); 1211 k_new_method->set_orig_method_idnum(num); 1212 if (thread->has_pending_exception()) { 1213 return JVMTI_ERROR_OUT_OF_MEMORY; 1214 } 1215 } 1216 log_trace(redefine, class, normalize) 1217 ("Method added: new: %s [%d]", k_new_method->name_and_sig_as_C_string(), ni); 1218 ++ni; // advance to next new method 1219 break; 1220 case deleted: 1221 // method deleted, see if it is OK 1222 if (!can_add_or_delete(k_old_method)) { 1223 log_info(redefine, class, normalize) 1224 ("redefined class %s methods error: deleted method %s [%d]", 1225 the_class->external_name(), k_old_method->name_and_sig_as_C_string(), oi); 1226 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED; 1227 } 1228 log_trace(redefine, class, normalize) 1229 ("Method deleted: old: %s [%d]", k_old_method->name_and_sig_as_C_string(), oi); 1230 ++oi; // advance to next old method 1231 break; 1232 default: 1233 ShouldNotReachHere(); 1234 } 1235 } 1236 1237 return JVMTI_ERROR_NONE; 1238 } 1239 1240 1241 // Find new constant pool index value for old constant pool index value 1242 // by seaching the index map. Returns zero (0) if there is no mapped 1243 // value for the old constant pool index. 1244 int VM_RedefineClasses::find_new_index(int old_index) { 1245 if (_index_map_count == 0) { 1246 // map is empty so nothing can be found 1247 return 0; 1248 } 1249 1250 if (old_index < 1 || old_index >= _index_map_p->length()) { 1251 // The old_index is out of range so it is not mapped. This should 1252 // not happen in regular constant pool merging use, but it can 1253 // happen if a corrupt annotation is processed. 1254 return 0; 1255 } 1256 1257 int value = _index_map_p->at(old_index); 1258 if (value == -1) { 1259 // the old_index is not mapped 1260 return 0; 1261 } 1262 1263 return value; 1264 } // end find_new_index() 1265 1266 1267 // Find new bootstrap specifier index value for old bootstrap specifier index 1268 // value by seaching the index map. Returns unused index (-1) if there is 1269 // no mapped value for the old bootstrap specifier index. 1270 int VM_RedefineClasses::find_new_operand_index(int old_index) { 1271 if (_operands_index_map_count == 0) { 1272 // map is empty so nothing can be found 1273 return -1; 1274 } 1275 1276 if (old_index == -1 || old_index >= _operands_index_map_p->length()) { 1277 // The old_index is out of range so it is not mapped. 1278 // This should not happen in regular constant pool merging use. 1279 return -1; 1280 } 1281 1282 int value = _operands_index_map_p->at(old_index); 1283 if (value == -1) { 1284 // the old_index is not mapped 1285 return -1; 1286 } 1287 1288 return value; 1289 } // end find_new_operand_index() 1290 1291 1292 // Returns true if the current mismatch is due to a resolved/unresolved 1293 // class pair. Otherwise, returns false. 1294 bool VM_RedefineClasses::is_unresolved_class_mismatch(const constantPoolHandle& cp1, 1295 int index1, const constantPoolHandle& cp2, int index2) { 1296 1297 jbyte t1 = cp1->tag_at(index1).value(); 1298 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) { 1299 return false; // wrong entry type; not our special case 1300 } 1301 1302 jbyte t2 = cp2->tag_at(index2).value(); 1303 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) { 1304 return false; // wrong entry type; not our special case 1305 } 1306 1307 if (t1 == t2) { 1308 return false; // not a mismatch; not our special case 1309 } 1310 1311 char *s1 = cp1->klass_name_at(index1)->as_C_string(); 1312 char *s2 = cp2->klass_name_at(index2)->as_C_string(); 1313 if (strcmp(s1, s2) != 0) { 1314 return false; // strings don't match; not our special case 1315 } 1316 1317 return true; // made it through the gauntlet; this is our special case 1318 } // end is_unresolved_class_mismatch() 1319 1320 1321 // The bug 6214132 caused the verification to fail. 1322 // 1. What's done in RedefineClasses() before verification: 1323 // a) A reference to the class being redefined (_the_class) and a 1324 // reference to new version of the class (_scratch_class) are 1325 // saved here for use during the bytecode verification phase of 1326 // RedefineClasses. 1327 // b) The _java_mirror field from _the_class is copied to the 1328 // _java_mirror field in _scratch_class. This means that a jclass 1329 // returned for _the_class or _scratch_class will refer to the 1330 // same Java mirror. The verifier will see the "one true mirror" 1331 // for the class being verified. 1332 // 2. See comments in JvmtiThreadState for what is done during verification. 1333 1334 class RedefineVerifyMark : public StackObj { 1335 private: 1336 JvmtiThreadState* _state; 1337 Klass* _scratch_class; 1338 Handle _scratch_mirror; 1339 1340 public: 1341 1342 RedefineVerifyMark(Klass* the_class, Klass* scratch_class, 1343 JvmtiThreadState* state) : _state(state), _scratch_class(scratch_class) 1344 { 1345 _state->set_class_versions_map(the_class, scratch_class); 1346 _scratch_mirror = Handle(_state->get_thread(), _scratch_class->java_mirror()); 1347 _scratch_class->replace_java_mirror(the_class->java_mirror()); 1348 } 1349 1350 ~RedefineVerifyMark() { 1351 // Restore the scratch class's mirror, so when scratch_class is removed 1352 // the correct mirror pointing to it can be cleared. 1353 _scratch_class->replace_java_mirror(_scratch_mirror()); 1354 _state->clear_class_versions_map(); 1355 } 1356 }; 1357 1358 1359 jvmtiError VM_RedefineClasses::load_new_class_versions() { 1360 1361 // For consistency allocate memory using os::malloc wrapper. 1362 _scratch_classes = (InstanceKlass**) 1363 os::malloc(sizeof(InstanceKlass*) * _class_count, mtClass); 1364 if (_scratch_classes == NULL) { 1365 return JVMTI_ERROR_OUT_OF_MEMORY; 1366 } 1367 // Zero initialize the _scratch_classes array. 1368 for (int i = 0; i < _class_count; i++) { 1369 _scratch_classes[i] = NULL; 1370 } 1371 1372 JavaThread* current = JavaThread::current(); 1373 ResourceMark rm(current); 1374 1375 JvmtiThreadState *state = JvmtiThreadState::state_for(current); 1376 // state can only be NULL if the current thread is exiting which 1377 // should not happen since we're trying to do a RedefineClasses 1378 guarantee(state != NULL, "exiting thread calling load_new_class_versions"); 1379 for (int i = 0; i < _class_count; i++) { 1380 // Create HandleMark so that any handles created while loading new class 1381 // versions are deleted. Constant pools are deallocated while merging 1382 // constant pools 1383 HandleMark hm(current); 1384 InstanceKlass* the_class = get_ik(_class_defs[i].klass); 1385 1386 log_debug(redefine, class, load) 1387 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)", 1388 the_class->external_name(), _class_load_kind, os::available_memory() >> 10); 1389 1390 ClassFileStream st((u1*)_class_defs[i].class_bytes, 1391 _class_defs[i].class_byte_count, 1392 "__VM_RedefineClasses__", 1393 ClassFileStream::verify); 1394 1395 // Set redefined class handle in JvmtiThreadState class. 1396 // This redefined class is sent to agent event handler for class file 1397 // load hook event. 1398 state->set_class_being_redefined(the_class, _class_load_kind); 1399 1400 JavaThread* THREAD = current; // For exception macros. 1401 ExceptionMark em(THREAD); 1402 Handle protection_domain(THREAD, the_class->protection_domain()); 1403 ClassLoadInfo cl_info(protection_domain); 1404 // Parse and create a class from the bytes, but this class isn't added 1405 // to the dictionary, so do not call resolve_from_stream. 1406 InstanceKlass* scratch_class = KlassFactory::create_from_stream(&st, 1407 the_class->name(), 1408 the_class->class_loader_data(), 1409 cl_info, 1410 THREAD); 1411 1412 // Clear class_being_redefined just to be sure. 1413 state->clear_class_being_redefined(); 1414 1415 // TODO: if this is retransform, and nothing changed we can skip it 1416 1417 // Need to clean up allocated InstanceKlass if there's an error so assign 1418 // the result here. Caller deallocates all the scratch classes in case of 1419 // an error. 1420 _scratch_classes[i] = scratch_class; 1421 1422 if (HAS_PENDING_EXCEPTION) { 1423 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1424 log_info(redefine, class, load, exceptions)("create_from_stream exception: '%s'", ex_name->as_C_string()); 1425 CLEAR_PENDING_EXCEPTION; 1426 1427 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) { 1428 return JVMTI_ERROR_UNSUPPORTED_VERSION; 1429 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) { 1430 return JVMTI_ERROR_INVALID_CLASS_FORMAT; 1431 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) { 1432 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION; 1433 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) { 1434 // The message will be "XXX (wrong name: YYY)" 1435 return JVMTI_ERROR_NAMES_DONT_MATCH; 1436 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1437 return JVMTI_ERROR_OUT_OF_MEMORY; 1438 } else { // Just in case more exceptions can be thrown.. 1439 return JVMTI_ERROR_FAILS_VERIFICATION; 1440 } 1441 } 1442 1443 // Ensure class is linked before redefine 1444 if (!the_class->is_linked()) { 1445 the_class->link_class(THREAD); 1446 if (HAS_PENDING_EXCEPTION) { 1447 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1448 oop message = java_lang_Throwable::message(PENDING_EXCEPTION); 1449 if (message != NULL) { 1450 char* ex_msg = java_lang_String::as_utf8_string(message); 1451 log_info(redefine, class, load, exceptions)("link_class exception: '%s %s'", 1452 ex_name->as_C_string(), ex_msg); 1453 } else { 1454 log_info(redefine, class, load, exceptions)("link_class exception: '%s'", 1455 ex_name->as_C_string()); 1456 } 1457 CLEAR_PENDING_EXCEPTION; 1458 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1459 return JVMTI_ERROR_OUT_OF_MEMORY; 1460 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) { 1461 return JVMTI_ERROR_INVALID_CLASS; 1462 } else { 1463 return JVMTI_ERROR_INTERNAL; 1464 } 1465 } 1466 } 1467 1468 // Do the validity checks in compare_and_normalize_class_versions() 1469 // before verifying the byte codes. By doing these checks first, we 1470 // limit the number of functions that require redirection from 1471 // the_class to scratch_class. In particular, we don't have to 1472 // modify JNI GetSuperclass() and thus won't change its performance. 1473 jvmtiError res = compare_and_normalize_class_versions(the_class, 1474 scratch_class); 1475 if (res != JVMTI_ERROR_NONE) { 1476 return res; 1477 } 1478 1479 // verify what the caller passed us 1480 { 1481 // The bug 6214132 caused the verification to fail. 1482 // Information about the_class and scratch_class is temporarily 1483 // recorded into jvmtiThreadState. This data is used to redirect 1484 // the_class to scratch_class in the JVM_* functions called by the 1485 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed 1486 // description. 1487 RedefineVerifyMark rvm(the_class, scratch_class, state); 1488 Verifier::verify(scratch_class, true, THREAD); 1489 } 1490 1491 if (HAS_PENDING_EXCEPTION) { 1492 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1493 log_info(redefine, class, load, exceptions)("verify_byte_codes exception: '%s'", ex_name->as_C_string()); 1494 CLEAR_PENDING_EXCEPTION; 1495 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1496 return JVMTI_ERROR_OUT_OF_MEMORY; 1497 } else { 1498 // tell the caller the bytecodes are bad 1499 return JVMTI_ERROR_FAILS_VERIFICATION; 1500 } 1501 } 1502 1503 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD); 1504 if (HAS_PENDING_EXCEPTION) { 1505 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1506 log_info(redefine, class, load, exceptions)("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string()); 1507 CLEAR_PENDING_EXCEPTION; 1508 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1509 return JVMTI_ERROR_OUT_OF_MEMORY; 1510 } else { 1511 return JVMTI_ERROR_INTERNAL; 1512 } 1513 } 1514 1515 #ifdef ASSERT 1516 { 1517 // verify what we have done during constant pool merging 1518 { 1519 RedefineVerifyMark rvm(the_class, scratch_class, state); 1520 Verifier::verify(scratch_class, true, THREAD); 1521 } 1522 1523 if (HAS_PENDING_EXCEPTION) { 1524 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1525 log_info(redefine, class, load, exceptions) 1526 ("verify_byte_codes post merge-CP exception: '%s'", ex_name->as_C_string()); 1527 CLEAR_PENDING_EXCEPTION; 1528 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1529 return JVMTI_ERROR_OUT_OF_MEMORY; 1530 } else { 1531 // tell the caller that constant pool merging screwed up 1532 return JVMTI_ERROR_INTERNAL; 1533 } 1534 } 1535 } 1536 #endif // ASSERT 1537 1538 Rewriter::rewrite(scratch_class, THREAD); 1539 if (!HAS_PENDING_EXCEPTION) { 1540 scratch_class->link_methods(THREAD); 1541 } 1542 if (HAS_PENDING_EXCEPTION) { 1543 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1544 log_info(redefine, class, load, exceptions) 1545 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string()); 1546 CLEAR_PENDING_EXCEPTION; 1547 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1548 return JVMTI_ERROR_OUT_OF_MEMORY; 1549 } else { 1550 return JVMTI_ERROR_INTERNAL; 1551 } 1552 } 1553 1554 log_debug(redefine, class, load) 1555 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)", the_class->external_name(), os::available_memory() >> 10); 1556 } 1557 1558 return JVMTI_ERROR_NONE; 1559 } 1560 1561 1562 // Map old_index to new_index as needed. scratch_cp is only needed 1563 // for log calls. 1564 void VM_RedefineClasses::map_index(const constantPoolHandle& scratch_cp, 1565 int old_index, int new_index) { 1566 if (find_new_index(old_index) != 0) { 1567 // old_index is already mapped 1568 return; 1569 } 1570 1571 if (old_index == new_index) { 1572 // no mapping is needed 1573 return; 1574 } 1575 1576 _index_map_p->at_put(old_index, new_index); 1577 _index_map_count++; 1578 1579 log_trace(redefine, class, constantpool) 1580 ("mapped tag %d at index %d to %d", scratch_cp->tag_at(old_index).value(), old_index, new_index); 1581 } // end map_index() 1582 1583 1584 // Map old_index to new_index as needed. 1585 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) { 1586 if (find_new_operand_index(old_index) != -1) { 1587 // old_index is already mapped 1588 return; 1589 } 1590 1591 if (old_index == new_index) { 1592 // no mapping is needed 1593 return; 1594 } 1595 1596 _operands_index_map_p->at_put(old_index, new_index); 1597 _operands_index_map_count++; 1598 1599 log_trace(redefine, class, constantpool)("mapped bootstrap specifier at index %d to %d", old_index, new_index); 1600 } // end map_index() 1601 1602 1603 // Merge old_cp and scratch_cp and return the results of the merge via 1604 // merge_cp_p. The number of entries in *merge_cp_p is returned via 1605 // merge_cp_length_p. The entries in old_cp occupy the same locations 1606 // in *merge_cp_p. Also creates a map of indices from entries in 1607 // scratch_cp to the corresponding entry in *merge_cp_p. Index map 1608 // entries are only created for entries in scratch_cp that occupy a 1609 // different location in *merged_cp_p. 1610 bool VM_RedefineClasses::merge_constant_pools(const constantPoolHandle& old_cp, 1611 const constantPoolHandle& scratch_cp, constantPoolHandle *merge_cp_p, 1612 int *merge_cp_length_p, TRAPS) { 1613 1614 if (merge_cp_p == NULL) { 1615 assert(false, "caller must provide scratch constantPool"); 1616 return false; // robustness 1617 } 1618 if (merge_cp_length_p == NULL) { 1619 assert(false, "caller must provide scratch CP length"); 1620 return false; // robustness 1621 } 1622 // Worst case we need old_cp->length() + scratch_cp()->length(), 1623 // but the caller might be smart so make sure we have at least 1624 // the minimum. 1625 if ((*merge_cp_p)->length() < old_cp->length()) { 1626 assert(false, "merge area too small"); 1627 return false; // robustness 1628 } 1629 1630 log_info(redefine, class, constantpool)("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(), scratch_cp->length()); 1631 1632 { 1633 // Pass 0: 1634 // The old_cp is copied to *merge_cp_p; this means that any code 1635 // using old_cp does not have to change. This work looks like a 1636 // perfect fit for ConstantPool*::copy_cp_to(), but we need to 1637 // handle one special case: 1638 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass 1639 // This will make verification happy. 1640 1641 int old_i; // index into old_cp 1642 1643 // index zero (0) is not used in constantPools 1644 for (old_i = 1; old_i < old_cp->length(); old_i++) { 1645 // leave debugging crumb 1646 jbyte old_tag = old_cp->tag_at(old_i).value(); 1647 switch (old_tag) { 1648 case JVM_CONSTANT_Class: 1649 case JVM_CONSTANT_UnresolvedClass: 1650 // revert the copy to JVM_CONSTANT_UnresolvedClass 1651 // May be resolving while calling this so do the same for 1652 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition) 1653 (*merge_cp_p)->temp_unresolved_klass_at_put(old_i, 1654 old_cp->klass_name_index_at(old_i)); 1655 break; 1656 1657 case JVM_CONSTANT_Double: 1658 case JVM_CONSTANT_Long: 1659 // just copy the entry to *merge_cp_p, but double and long take 1660 // two constant pool entries 1661 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i); 1662 old_i++; 1663 break; 1664 1665 default: 1666 // just copy the entry to *merge_cp_p 1667 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i); 1668 break; 1669 } 1670 } // end for each old_cp entry 1671 1672 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_false); 1673 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_false); 1674 1675 // We don't need to sanity check that *merge_cp_length_p is within 1676 // *merge_cp_p bounds since we have the minimum on-entry check above. 1677 (*merge_cp_length_p) = old_i; 1678 } 1679 1680 // merge_cp_len should be the same as old_cp->length() at this point 1681 // so this trace message is really a "warm-and-breathing" message. 1682 log_debug(redefine, class, constantpool)("after pass 0: merge_cp_len=%d", *merge_cp_length_p); 1683 1684 int scratch_i; // index into scratch_cp 1685 { 1686 // Pass 1a: 1687 // Compare scratch_cp entries to the old_cp entries that we have 1688 // already copied to *merge_cp_p. In this pass, we are eliminating 1689 // exact duplicates (matching entry at same index) so we only 1690 // compare entries in the common indice range. 1691 int increment = 1; 1692 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length()); 1693 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) { 1694 switch (scratch_cp->tag_at(scratch_i).value()) { 1695 case JVM_CONSTANT_Double: 1696 case JVM_CONSTANT_Long: 1697 // double and long take two constant pool entries 1698 increment = 2; 1699 break; 1700 1701 default: 1702 increment = 1; 1703 break; 1704 } 1705 1706 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p, scratch_i); 1707 if (match) { 1708 // found a match at the same index so nothing more to do 1709 continue; 1710 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i, 1711 *merge_cp_p, scratch_i)) { 1712 // The mismatch in compare_entry_to() above is because of a 1713 // resolved versus unresolved class entry at the same index 1714 // with the same string value. Since Pass 0 reverted any 1715 // class entries to unresolved class entries in *merge_cp_p, 1716 // we go with the unresolved class entry. 1717 continue; 1718 } 1719 1720 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p); 1721 if (found_i != 0) { 1722 guarantee(found_i != scratch_i, 1723 "compare_entry_to() and find_matching_entry() do not agree"); 1724 1725 // Found a matching entry somewhere else in *merge_cp_p so 1726 // just need a mapping entry. 1727 map_index(scratch_cp, scratch_i, found_i); 1728 continue; 1729 } 1730 1731 // The find_matching_entry() call above could fail to find a match 1732 // due to a resolved versus unresolved class or string entry situation 1733 // like we solved above with the is_unresolved_*_mismatch() calls. 1734 // However, we would have to call is_unresolved_*_mismatch() over 1735 // all of *merge_cp_p (potentially) and that doesn't seem to be 1736 // worth the time. 1737 1738 // No match found so we have to append this entry and any unique 1739 // referenced entries to *merge_cp_p. 1740 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p); 1741 } 1742 } 1743 1744 log_debug(redefine, class, constantpool) 1745 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", 1746 *merge_cp_length_p, scratch_i, _index_map_count); 1747 1748 if (scratch_i < scratch_cp->length()) { 1749 // Pass 1b: 1750 // old_cp is smaller than scratch_cp so there are entries in 1751 // scratch_cp that we have not yet processed. We take care of 1752 // those now. 1753 int increment = 1; 1754 for (; scratch_i < scratch_cp->length(); scratch_i += increment) { 1755 switch (scratch_cp->tag_at(scratch_i).value()) { 1756 case JVM_CONSTANT_Double: 1757 case JVM_CONSTANT_Long: 1758 // double and long take two constant pool entries 1759 increment = 2; 1760 break; 1761 1762 default: 1763 increment = 1; 1764 break; 1765 } 1766 1767 int found_i = 1768 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p); 1769 if (found_i != 0) { 1770 // Found a matching entry somewhere else in *merge_cp_p so 1771 // just need a mapping entry. 1772 map_index(scratch_cp, scratch_i, found_i); 1773 continue; 1774 } 1775 1776 // No match found so we have to append this entry and any unique 1777 // referenced entries to *merge_cp_p. 1778 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p); 1779 } 1780 1781 log_debug(redefine, class, constantpool) 1782 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", 1783 *merge_cp_length_p, scratch_i, _index_map_count); 1784 } 1785 finalize_operands_merge(*merge_cp_p, CHECK_false); 1786 1787 return true; 1788 } // end merge_constant_pools() 1789 1790 1791 // Scoped object to clean up the constant pool(s) created for merging 1792 class MergeCPCleaner { 1793 ClassLoaderData* _loader_data; 1794 ConstantPool* _cp; 1795 ConstantPool* _scratch_cp; 1796 public: 1797 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) : 1798 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {} 1799 ~MergeCPCleaner() { 1800 _loader_data->add_to_deallocate_list(_cp); 1801 if (_scratch_cp != NULL) { 1802 _loader_data->add_to_deallocate_list(_scratch_cp); 1803 } 1804 } 1805 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; } 1806 }; 1807 1808 // Merge constant pools between the_class and scratch_class and 1809 // potentially rewrite bytecodes in scratch_class to use the merged 1810 // constant pool. 1811 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite( 1812 InstanceKlass* the_class, InstanceKlass* scratch_class, 1813 TRAPS) { 1814 // worst case merged constant pool length is old and new combined 1815 int merge_cp_length = the_class->constants()->length() 1816 + scratch_class->constants()->length(); 1817 1818 // Constant pools are not easily reused so we allocate a new one 1819 // each time. 1820 // merge_cp is created unsafe for concurrent GC processing. It 1821 // should be marked safe before discarding it. Even though 1822 // garbage, if it crosses a card boundary, it may be scanned 1823 // in order to find the start of the first complete object on the card. 1824 ClassLoaderData* loader_data = the_class->class_loader_data(); 1825 ConstantPool* merge_cp_oop = 1826 ConstantPool::allocate(loader_data, 1827 merge_cp_length, 1828 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1829 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop); 1830 1831 HandleMark hm(THREAD); // make sure handles are cleared before 1832 // MergeCPCleaner clears out merge_cp_oop 1833 constantPoolHandle merge_cp(THREAD, merge_cp_oop); 1834 1835 // Get constants() from the old class because it could have been rewritten 1836 // while we were at a safepoint allocating a new constant pool. 1837 constantPoolHandle old_cp(THREAD, the_class->constants()); 1838 constantPoolHandle scratch_cp(THREAD, scratch_class->constants()); 1839 1840 // If the length changed, the class was redefined out from under us. Return 1841 // an error. 1842 if (merge_cp_length != the_class->constants()->length() 1843 + scratch_class->constants()->length()) { 1844 return JVMTI_ERROR_INTERNAL; 1845 } 1846 1847 // Update the version number of the constant pools (may keep scratch_cp) 1848 merge_cp->increment_and_save_version(old_cp->version()); 1849 scratch_cp->increment_and_save_version(old_cp->version()); 1850 1851 ResourceMark rm(THREAD); 1852 _index_map_count = 0; 1853 _index_map_p = new intArray(scratch_cp->length(), scratch_cp->length(), -1); 1854 1855 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands()); 1856 _operands_index_map_count = 0; 1857 int operands_index_map_len = ConstantPool::operand_array_length(scratch_cp->operands()); 1858 _operands_index_map_p = new intArray(operands_index_map_len, operands_index_map_len, -1); 1859 1860 // reference to the cp holder is needed for copy_operands() 1861 merge_cp->set_pool_holder(scratch_class); 1862 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp, 1863 &merge_cp_length, THREAD); 1864 merge_cp->set_pool_holder(NULL); 1865 1866 if (!result) { 1867 // The merge can fail due to memory allocation failure or due 1868 // to robustness checks. 1869 return JVMTI_ERROR_INTERNAL; 1870 } 1871 1872 // Set dynamic constants attribute from the original CP. 1873 if (old_cp->has_dynamic_constant()) { 1874 scratch_cp->set_has_dynamic_constant(); 1875 } 1876 // Copy attributes from scratch_cp to merge_cp 1877 merge_cp->copy_fields(scratch_cp()); 1878 1879 log_info(redefine, class, constantpool)("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count); 1880 1881 if (_index_map_count == 0) { 1882 // there is nothing to map between the new and merged constant pools 1883 1884 if (old_cp->length() == scratch_cp->length()) { 1885 // The old and new constant pools are the same length and the 1886 // index map is empty. This means that the three constant pools 1887 // are equivalent (but not the same). Unfortunately, the new 1888 // constant pool has not gone through link resolution nor have 1889 // the new class bytecodes gone through constant pool cache 1890 // rewriting so we can't use the old constant pool with the new 1891 // class. 1892 1893 // toss the merged constant pool at return 1894 } else if (old_cp->length() < scratch_cp->length()) { 1895 // The old constant pool has fewer entries than the new constant 1896 // pool and the index map is empty. This means the new constant 1897 // pool is a superset of the old constant pool. However, the old 1898 // class bytecodes have already gone through constant pool cache 1899 // rewriting so we can't use the new constant pool with the old 1900 // class. 1901 1902 // toss the merged constant pool at return 1903 } else { 1904 // The old constant pool has more entries than the new constant 1905 // pool and the index map is empty. This means that both the old 1906 // and merged constant pools are supersets of the new constant 1907 // pool. 1908 1909 // Replace the new constant pool with a shrunken copy of the 1910 // merged constant pool 1911 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, 1912 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1913 // The new constant pool replaces scratch_cp so have cleaner clean it up. 1914 // It can't be cleaned up while there are handles to it. 1915 cp_cleaner.add_scratch_cp(scratch_cp()); 1916 } 1917 } else { 1918 if (log_is_enabled(Trace, redefine, class, constantpool)) { 1919 // don't want to loop unless we are tracing 1920 int count = 0; 1921 for (int i = 1; i < _index_map_p->length(); i++) { 1922 int value = _index_map_p->at(i); 1923 1924 if (value != -1) { 1925 log_trace(redefine, class, constantpool)("index_map[%d]: old=%d new=%d", count, i, value); 1926 count++; 1927 } 1928 } 1929 } 1930 1931 // We have entries mapped between the new and merged constant pools 1932 // so we have to rewrite some constant pool references. 1933 if (!rewrite_cp_refs(scratch_class)) { 1934 return JVMTI_ERROR_INTERNAL; 1935 } 1936 1937 // Replace the new constant pool with a shrunken copy of the 1938 // merged constant pool so now the rewritten bytecodes have 1939 // valid references; the previous new constant pool will get 1940 // GCed. 1941 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, 1942 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1943 // The new constant pool replaces scratch_cp so have cleaner clean it up. 1944 // It can't be cleaned up while there are handles to it. 1945 cp_cleaner.add_scratch_cp(scratch_cp()); 1946 } 1947 1948 return JVMTI_ERROR_NONE; 1949 } // end merge_cp_and_rewrite() 1950 1951 1952 // Rewrite constant pool references in klass scratch_class. 1953 bool VM_RedefineClasses::rewrite_cp_refs(InstanceKlass* scratch_class) { 1954 1955 // rewrite constant pool references in the nest attributes: 1956 if (!rewrite_cp_refs_in_nest_attributes(scratch_class)) { 1957 // propagate failure back to caller 1958 return false; 1959 } 1960 1961 // rewrite constant pool references in the Record attribute: 1962 if (!rewrite_cp_refs_in_record_attribute(scratch_class)) { 1963 // propagate failure back to caller 1964 return false; 1965 } 1966 1967 // rewrite constant pool references in the PermittedSubclasses attribute: 1968 if (!rewrite_cp_refs_in_permitted_subclasses_attribute(scratch_class)) { 1969 // propagate failure back to caller 1970 return false; 1971 } 1972 1973 // rewrite constant pool references in the Preload attribute: 1974 if (!rewrite_cp_refs_in_preload_attribute(scratch_class)) { 1975 // propagate failure back to caller 1976 return false; 1977 } 1978 1979 // rewrite constant pool references in the methods: 1980 if (!rewrite_cp_refs_in_methods(scratch_class)) { 1981 // propagate failure back to caller 1982 return false; 1983 } 1984 1985 // rewrite constant pool references in the class_annotations: 1986 if (!rewrite_cp_refs_in_class_annotations(scratch_class)) { 1987 // propagate failure back to caller 1988 return false; 1989 } 1990 1991 // rewrite constant pool references in the fields_annotations: 1992 if (!rewrite_cp_refs_in_fields_annotations(scratch_class)) { 1993 // propagate failure back to caller 1994 return false; 1995 } 1996 1997 // rewrite constant pool references in the methods_annotations: 1998 if (!rewrite_cp_refs_in_methods_annotations(scratch_class)) { 1999 // propagate failure back to caller 2000 return false; 2001 } 2002 2003 // rewrite constant pool references in the methods_parameter_annotations: 2004 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class)) { 2005 // propagate failure back to caller 2006 return false; 2007 } 2008 2009 // rewrite constant pool references in the methods_default_annotations: 2010 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class)) { 2011 // propagate failure back to caller 2012 return false; 2013 } 2014 2015 // rewrite constant pool references in the class_type_annotations: 2016 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class)) { 2017 // propagate failure back to caller 2018 return false; 2019 } 2020 2021 // rewrite constant pool references in the fields_type_annotations: 2022 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class)) { 2023 // propagate failure back to caller 2024 return false; 2025 } 2026 2027 // rewrite constant pool references in the methods_type_annotations: 2028 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class)) { 2029 // propagate failure back to caller 2030 return false; 2031 } 2032 2033 // There can be type annotations in the Code part of a method_info attribute. 2034 // These annotations are not accessible, even by reflection. 2035 // Currently they are not even parsed by the ClassFileParser. 2036 // If runtime access is added they will also need to be rewritten. 2037 2038 // rewrite source file name index: 2039 u2 source_file_name_idx = scratch_class->source_file_name_index(); 2040 if (source_file_name_idx != 0) { 2041 u2 new_source_file_name_idx = find_new_index(source_file_name_idx); 2042 if (new_source_file_name_idx != 0) { 2043 scratch_class->set_source_file_name_index(new_source_file_name_idx); 2044 } 2045 } 2046 2047 // rewrite class generic signature index: 2048 u2 generic_signature_index = scratch_class->generic_signature_index(); 2049 if (generic_signature_index != 0) { 2050 u2 new_generic_signature_index = find_new_index(generic_signature_index); 2051 if (new_generic_signature_index != 0) { 2052 scratch_class->set_generic_signature_index(new_generic_signature_index); 2053 } 2054 } 2055 2056 return true; 2057 } // end rewrite_cp_refs() 2058 2059 // Rewrite constant pool references in the NestHost and NestMembers attributes. 2060 bool VM_RedefineClasses::rewrite_cp_refs_in_nest_attributes( 2061 InstanceKlass* scratch_class) { 2062 2063 u2 cp_index = scratch_class->nest_host_index(); 2064 if (cp_index != 0) { 2065 scratch_class->set_nest_host_index(find_new_index(cp_index)); 2066 } 2067 Array<u2>* nest_members = scratch_class->nest_members(); 2068 for (int i = 0; i < nest_members->length(); i++) { 2069 u2 cp_index = nest_members->at(i); 2070 nest_members->at_put(i, find_new_index(cp_index)); 2071 } 2072 return true; 2073 } 2074 2075 // Rewrite constant pool references in the Record attribute. 2076 bool VM_RedefineClasses::rewrite_cp_refs_in_record_attribute(InstanceKlass* scratch_class) { 2077 Array<RecordComponent*>* components = scratch_class->record_components(); 2078 if (components != NULL) { 2079 for (int i = 0; i < components->length(); i++) { 2080 RecordComponent* component = components->at(i); 2081 u2 cp_index = component->name_index(); 2082 component->set_name_index(find_new_index(cp_index)); 2083 cp_index = component->descriptor_index(); 2084 component->set_descriptor_index(find_new_index(cp_index)); 2085 cp_index = component->generic_signature_index(); 2086 if (cp_index != 0) { 2087 component->set_generic_signature_index(find_new_index(cp_index)); 2088 } 2089 2090 AnnotationArray* annotations = component->annotations(); 2091 if (annotations != NULL && annotations->length() != 0) { 2092 int byte_i = 0; // byte index into annotations 2093 if (!rewrite_cp_refs_in_annotations_typeArray(annotations, byte_i)) { 2094 log_debug(redefine, class, annotation)("bad record_component_annotations at %d", i); 2095 // propagate failure back to caller 2096 return false; 2097 } 2098 } 2099 2100 AnnotationArray* type_annotations = component->type_annotations(); 2101 if (type_annotations != NULL && type_annotations->length() != 0) { 2102 int byte_i = 0; // byte index into annotations 2103 if (!rewrite_cp_refs_in_annotations_typeArray(type_annotations, byte_i)) { 2104 log_debug(redefine, class, annotation)("bad record_component_type_annotations at %d", i); 2105 // propagate failure back to caller 2106 return false; 2107 } 2108 } 2109 } 2110 } 2111 return true; 2112 } 2113 2114 // Rewrite constant pool references in the PermittedSubclasses attribute. 2115 bool VM_RedefineClasses::rewrite_cp_refs_in_permitted_subclasses_attribute( 2116 InstanceKlass* scratch_class) { 2117 2118 Array<u2>* permitted_subclasses = scratch_class->permitted_subclasses(); 2119 assert(permitted_subclasses != NULL, "unexpected null permitted_subclasses"); 2120 for (int i = 0; i < permitted_subclasses->length(); i++) { 2121 u2 cp_index = permitted_subclasses->at(i); 2122 permitted_subclasses->at_put(i, find_new_index(cp_index)); 2123 } 2124 return true; 2125 } 2126 2127 // Rewrite constant pool references in the Preload attribute. 2128 bool VM_RedefineClasses::rewrite_cp_refs_in_preload_attribute( 2129 InstanceKlass* scratch_class) { 2130 2131 Array<u2>* preload_classes = scratch_class->preload_classes(); 2132 assert(preload_classes != NULL, "unexpected null preload_classes"); 2133 for (int i = 0; i < preload_classes->length(); i++) { 2134 u2 cp_index = preload_classes->at(i); 2135 preload_classes->at_put(i, find_new_index(cp_index)); 2136 } 2137 return true; 2138 } 2139 2140 // Rewrite constant pool references in the methods. 2141 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(InstanceKlass* scratch_class) { 2142 2143 Array<Method*>* methods = scratch_class->methods(); 2144 2145 if (methods == NULL || methods->length() == 0) { 2146 // no methods so nothing to do 2147 return true; 2148 } 2149 2150 JavaThread* THREAD = JavaThread::current(); // For exception macros. 2151 ExceptionMark em(THREAD); 2152 2153 // rewrite constant pool references in the methods: 2154 for (int i = methods->length() - 1; i >= 0; i--) { 2155 methodHandle method(THREAD, methods->at(i)); 2156 methodHandle new_method; 2157 rewrite_cp_refs_in_method(method, &new_method, THREAD); 2158 if (!new_method.is_null()) { 2159 // the method has been replaced so save the new method version 2160 // even in the case of an exception. original method is on the 2161 // deallocation list. 2162 methods->at_put(i, new_method()); 2163 } 2164 if (HAS_PENDING_EXCEPTION) { 2165 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 2166 log_info(redefine, class, load, exceptions)("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string()); 2167 // Need to clear pending exception here as the super caller sets 2168 // the JVMTI_ERROR_INTERNAL if the returned value is false. 2169 CLEAR_PENDING_EXCEPTION; 2170 return false; 2171 } 2172 } 2173 2174 return true; 2175 } 2176 2177 2178 // Rewrite constant pool references in the specific method. This code 2179 // was adapted from Rewriter::rewrite_method(). 2180 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method, 2181 methodHandle *new_method_p, TRAPS) { 2182 2183 *new_method_p = methodHandle(); // default is no new method 2184 2185 // We cache a pointer to the bytecodes here in code_base. If GC 2186 // moves the Method*, then the bytecodes will also move which 2187 // will likely cause a crash. We create a NoSafepointVerifier 2188 // object to detect whether we pass a possible safepoint in this 2189 // code block. 2190 NoSafepointVerifier nsv; 2191 2192 // Bytecodes and their length 2193 address code_base = method->code_base(); 2194 int code_length = method->code_size(); 2195 2196 int bc_length; 2197 for (int bci = 0; bci < code_length; bci += bc_length) { 2198 address bcp = code_base + bci; 2199 Bytecodes::Code c = (Bytecodes::Code)(*bcp); 2200 2201 bc_length = Bytecodes::length_for(c); 2202 if (bc_length == 0) { 2203 // More complicated bytecodes report a length of zero so 2204 // we have to try again a slightly different way. 2205 bc_length = Bytecodes::length_at(method(), bcp); 2206 } 2207 2208 assert(bc_length != 0, "impossible bytecode length"); 2209 2210 switch (c) { 2211 case Bytecodes::_ldc: 2212 { 2213 int cp_index = *(bcp + 1); 2214 int new_index = find_new_index(cp_index); 2215 2216 if (StressLdcRewrite && new_index == 0) { 2217 // If we are stressing ldc -> ldc_w rewriting, then we 2218 // always need a new_index value. 2219 new_index = cp_index; 2220 } 2221 if (new_index != 0) { 2222 // the original index is mapped so we have more work to do 2223 if (!StressLdcRewrite && new_index <= max_jubyte) { 2224 // The new value can still use ldc instead of ldc_w 2225 // unless we are trying to stress ldc -> ldc_w rewriting 2226 log_trace(redefine, class, constantpool) 2227 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index); 2228 *(bcp + 1) = new_index; 2229 } else { 2230 log_trace(redefine, class, constantpool) 2231 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index); 2232 // the new value needs ldc_w instead of ldc 2233 u_char inst_buffer[4]; // max instruction size is 4 bytes 2234 bcp = (address)inst_buffer; 2235 // construct new instruction sequence 2236 *bcp = Bytecodes::_ldc_w; 2237 bcp++; 2238 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w. 2239 // See comment below for difference between put_Java_u2() 2240 // and put_native_u2(). 2241 Bytes::put_Java_u2(bcp, new_index); 2242 2243 Relocator rc(method, NULL /* no RelocatorListener needed */); 2244 methodHandle m; 2245 { 2246 PauseNoSafepointVerifier pnsv(&nsv); 2247 2248 // ldc is 2 bytes and ldc_w is 3 bytes 2249 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK); 2250 } 2251 2252 // return the new method so that the caller can update 2253 // the containing class 2254 *new_method_p = method = m; 2255 // switch our bytecode processing loop from the old method 2256 // to the new method 2257 code_base = method->code_base(); 2258 code_length = method->code_size(); 2259 bcp = code_base + bci; 2260 c = (Bytecodes::Code)(*bcp); 2261 bc_length = Bytecodes::length_for(c); 2262 assert(bc_length != 0, "sanity check"); 2263 } // end we need ldc_w instead of ldc 2264 } // end if there is a mapped index 2265 } break; 2266 2267 // these bytecodes have a two-byte constant pool index 2268 case Bytecodes::_anewarray : // fall through 2269 case Bytecodes::_checkcast : // fall through 2270 case Bytecodes::_getfield : // fall through 2271 case Bytecodes::_getstatic : // fall through 2272 case Bytecodes::_aconst_init : // fall through 2273 case Bytecodes::_withfield : // fall through 2274 case Bytecodes::_instanceof : // fall through 2275 case Bytecodes::_invokedynamic : // fall through 2276 case Bytecodes::_invokeinterface: // fall through 2277 case Bytecodes::_invokespecial : // fall through 2278 case Bytecodes::_invokestatic : // fall through 2279 case Bytecodes::_invokevirtual : // fall through 2280 case Bytecodes::_ldc_w : // fall through 2281 case Bytecodes::_ldc2_w : // fall through 2282 case Bytecodes::_multianewarray : // fall through 2283 case Bytecodes::_new : // fall through 2284 case Bytecodes::_putfield : // fall through 2285 case Bytecodes::_putstatic : 2286 { 2287 address p = bcp + 1; 2288 int cp_index = Bytes::get_Java_u2(p); 2289 int new_index = find_new_index(cp_index); 2290 if (new_index != 0) { 2291 // the original index is mapped so update w/ new value 2292 log_trace(redefine, class, constantpool) 2293 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),p2i(bcp), cp_index, new_index); 2294 // Rewriter::rewrite_method() uses put_native_u2() in this 2295 // situation because it is reusing the constant pool index 2296 // location for a native index into the ConstantPoolCache. 2297 // Since we are updating the constant pool index prior to 2298 // verification and ConstantPoolCache initialization, we 2299 // need to keep the new index in Java byte order. 2300 Bytes::put_Java_u2(p, new_index); 2301 } 2302 } break; 2303 default: 2304 break; 2305 } 2306 } // end for each bytecode 2307 } // end rewrite_cp_refs_in_method() 2308 2309 2310 // Rewrite constant pool references in the class_annotations field. 2311 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(InstanceKlass* scratch_class) { 2312 2313 AnnotationArray* class_annotations = scratch_class->class_annotations(); 2314 if (class_annotations == NULL || class_annotations->length() == 0) { 2315 // no class_annotations so nothing to do 2316 return true; 2317 } 2318 2319 log_debug(redefine, class, annotation)("class_annotations length=%d", class_annotations->length()); 2320 2321 int byte_i = 0; // byte index into class_annotations 2322 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i); 2323 } 2324 2325 2326 // Rewrite constant pool references in an annotations typeArray. This 2327 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute 2328 // that is described in section 4.8.15 of the 2nd-edition of the VM spec: 2329 // 2330 // annotations_typeArray { 2331 // u2 num_annotations; 2332 // annotation annotations[num_annotations]; 2333 // } 2334 // 2335 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray( 2336 AnnotationArray* annotations_typeArray, int &byte_i_ref) { 2337 2338 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2339 // not enough room for num_annotations field 2340 log_debug(redefine, class, annotation)("length() is too small for num_annotations field"); 2341 return false; 2342 } 2343 2344 u2 num_annotations = Bytes::get_Java_u2((address) 2345 annotations_typeArray->adr_at(byte_i_ref)); 2346 byte_i_ref += 2; 2347 2348 log_debug(redefine, class, annotation)("num_annotations=%d", num_annotations); 2349 2350 int calc_num_annotations = 0; 2351 for (; calc_num_annotations < num_annotations; calc_num_annotations++) { 2352 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, byte_i_ref)) { 2353 log_debug(redefine, class, annotation)("bad annotation_struct at %d", calc_num_annotations); 2354 // propagate failure back to caller 2355 return false; 2356 } 2357 } 2358 assert(num_annotations == calc_num_annotations, "sanity check"); 2359 2360 return true; 2361 } // end rewrite_cp_refs_in_annotations_typeArray() 2362 2363 2364 // Rewrite constant pool references in the annotation struct portion of 2365 // an annotations_typeArray. This "structure" is from section 4.8.15 of 2366 // the 2nd-edition of the VM spec: 2367 // 2368 // struct annotation { 2369 // u2 type_index; 2370 // u2 num_element_value_pairs; 2371 // { 2372 // u2 element_name_index; 2373 // element_value value; 2374 // } element_value_pairs[num_element_value_pairs]; 2375 // } 2376 // 2377 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct( 2378 AnnotationArray* annotations_typeArray, int &byte_i_ref) { 2379 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) { 2380 // not enough room for smallest annotation_struct 2381 log_debug(redefine, class, annotation)("length() is too small for annotation_struct"); 2382 return false; 2383 } 2384 2385 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray, 2386 byte_i_ref, "type_index"); 2387 2388 u2 num_element_value_pairs = Bytes::get_Java_u2((address) 2389 annotations_typeArray->adr_at(byte_i_ref)); 2390 byte_i_ref += 2; 2391 2392 log_debug(redefine, class, annotation) 2393 ("type_index=%d num_element_value_pairs=%d", type_index, num_element_value_pairs); 2394 2395 int calc_num_element_value_pairs = 0; 2396 for (; calc_num_element_value_pairs < num_element_value_pairs; 2397 calc_num_element_value_pairs++) { 2398 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2399 // not enough room for another element_name_index, let alone 2400 // the rest of another component 2401 log_debug(redefine, class, annotation)("length() is too small for element_name_index"); 2402 return false; 2403 } 2404 2405 u2 element_name_index = rewrite_cp_ref_in_annotation_data( 2406 annotations_typeArray, byte_i_ref, 2407 "element_name_index"); 2408 2409 log_debug(redefine, class, annotation)("element_name_index=%d", element_name_index); 2410 2411 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, byte_i_ref)) { 2412 log_debug(redefine, class, annotation)("bad element_value at %d", calc_num_element_value_pairs); 2413 // propagate failure back to caller 2414 return false; 2415 } 2416 } // end for each component 2417 assert(num_element_value_pairs == calc_num_element_value_pairs, 2418 "sanity check"); 2419 2420 return true; 2421 } // end rewrite_cp_refs_in_annotation_struct() 2422 2423 2424 // Rewrite a constant pool reference at the current position in 2425 // annotations_typeArray if needed. Returns the original constant 2426 // pool reference if a rewrite was not needed or the new constant 2427 // pool reference if a rewrite was needed. 2428 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data( 2429 AnnotationArray* annotations_typeArray, int &byte_i_ref, 2430 const char * trace_mesg) { 2431 2432 address cp_index_addr = (address) 2433 annotations_typeArray->adr_at(byte_i_ref); 2434 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr); 2435 u2 new_cp_index = find_new_index(old_cp_index); 2436 if (new_cp_index != 0) { 2437 log_debug(redefine, class, annotation)("mapped old %s=%d", trace_mesg, old_cp_index); 2438 Bytes::put_Java_u2(cp_index_addr, new_cp_index); 2439 old_cp_index = new_cp_index; 2440 } 2441 byte_i_ref += 2; 2442 return old_cp_index; 2443 } 2444 2445 2446 // Rewrite constant pool references in the element_value portion of an 2447 // annotations_typeArray. This "structure" is from section 4.8.15.1 of 2448 // the 2nd-edition of the VM spec: 2449 // 2450 // struct element_value { 2451 // u1 tag; 2452 // union { 2453 // u2 const_value_index; 2454 // { 2455 // u2 type_name_index; 2456 // u2 const_name_index; 2457 // } enum_const_value; 2458 // u2 class_info_index; 2459 // annotation annotation_value; 2460 // struct { 2461 // u2 num_values; 2462 // element_value values[num_values]; 2463 // } array_value; 2464 // } value; 2465 // } 2466 // 2467 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value( 2468 AnnotationArray* annotations_typeArray, int &byte_i_ref) { 2469 2470 if ((byte_i_ref + 1) > annotations_typeArray->length()) { 2471 // not enough room for a tag let alone the rest of an element_value 2472 log_debug(redefine, class, annotation)("length() is too small for a tag"); 2473 return false; 2474 } 2475 2476 u1 tag = annotations_typeArray->at(byte_i_ref); 2477 byte_i_ref++; 2478 log_debug(redefine, class, annotation)("tag='%c'", tag); 2479 2480 switch (tag) { 2481 // These BaseType tag values are from Table 4.2 in VM spec: 2482 case JVM_SIGNATURE_BYTE: 2483 case JVM_SIGNATURE_CHAR: 2484 case JVM_SIGNATURE_DOUBLE: 2485 case JVM_SIGNATURE_FLOAT: 2486 case JVM_SIGNATURE_INT: 2487 case JVM_SIGNATURE_LONG: 2488 case JVM_SIGNATURE_SHORT: 2489 case JVM_SIGNATURE_BOOLEAN: 2490 2491 // The remaining tag values are from Table 4.8 in the 2nd-edition of 2492 // the VM spec: 2493 case 's': 2494 { 2495 // For the above tag values (including the BaseType values), 2496 // value.const_value_index is right union field. 2497 2498 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2499 // not enough room for a const_value_index 2500 log_debug(redefine, class, annotation)("length() is too small for a const_value_index"); 2501 return false; 2502 } 2503 2504 u2 const_value_index = rewrite_cp_ref_in_annotation_data( 2505 annotations_typeArray, byte_i_ref, 2506 "const_value_index"); 2507 2508 log_debug(redefine, class, annotation)("const_value_index=%d", const_value_index); 2509 } break; 2510 2511 case 'e': 2512 { 2513 // for the above tag value, value.enum_const_value is right union field 2514 2515 if ((byte_i_ref + 4) > annotations_typeArray->length()) { 2516 // not enough room for a enum_const_value 2517 log_debug(redefine, class, annotation)("length() is too small for a enum_const_value"); 2518 return false; 2519 } 2520 2521 u2 type_name_index = rewrite_cp_ref_in_annotation_data( 2522 annotations_typeArray, byte_i_ref, 2523 "type_name_index"); 2524 2525 u2 const_name_index = rewrite_cp_ref_in_annotation_data( 2526 annotations_typeArray, byte_i_ref, 2527 "const_name_index"); 2528 2529 log_debug(redefine, class, annotation) 2530 ("type_name_index=%d const_name_index=%d", type_name_index, const_name_index); 2531 } break; 2532 2533 case 'c': 2534 { 2535 // for the above tag value, value.class_info_index is right union field 2536 2537 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2538 // not enough room for a class_info_index 2539 log_debug(redefine, class, annotation)("length() is too small for a class_info_index"); 2540 return false; 2541 } 2542 2543 u2 class_info_index = rewrite_cp_ref_in_annotation_data( 2544 annotations_typeArray, byte_i_ref, 2545 "class_info_index"); 2546 2547 log_debug(redefine, class, annotation)("class_info_index=%d", class_info_index); 2548 } break; 2549 2550 case '@': 2551 // For the above tag value, value.attr_value is the right union 2552 // field. This is a nested annotation. 2553 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, byte_i_ref)) { 2554 // propagate failure back to caller 2555 return false; 2556 } 2557 break; 2558 2559 case JVM_SIGNATURE_ARRAY: 2560 { 2561 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2562 // not enough room for a num_values field 2563 log_debug(redefine, class, annotation)("length() is too small for a num_values field"); 2564 return false; 2565 } 2566 2567 // For the above tag value, value.array_value is the right union 2568 // field. This is an array of nested element_value. 2569 u2 num_values = Bytes::get_Java_u2((address) 2570 annotations_typeArray->adr_at(byte_i_ref)); 2571 byte_i_ref += 2; 2572 log_debug(redefine, class, annotation)("num_values=%d", num_values); 2573 2574 int calc_num_values = 0; 2575 for (; calc_num_values < num_values; calc_num_values++) { 2576 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, byte_i_ref)) { 2577 log_debug(redefine, class, annotation)("bad nested element_value at %d", calc_num_values); 2578 // propagate failure back to caller 2579 return false; 2580 } 2581 } 2582 assert(num_values == calc_num_values, "sanity check"); 2583 } break; 2584 2585 default: 2586 log_debug(redefine, class, annotation)("bad tag=0x%x", tag); 2587 return false; 2588 } // end decode tag field 2589 2590 return true; 2591 } // end rewrite_cp_refs_in_element_value() 2592 2593 2594 // Rewrite constant pool references in a fields_annotations field. 2595 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations( 2596 InstanceKlass* scratch_class) { 2597 2598 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations(); 2599 2600 if (fields_annotations == NULL || fields_annotations->length() == 0) { 2601 // no fields_annotations so nothing to do 2602 return true; 2603 } 2604 2605 log_debug(redefine, class, annotation)("fields_annotations length=%d", fields_annotations->length()); 2606 2607 for (int i = 0; i < fields_annotations->length(); i++) { 2608 AnnotationArray* field_annotations = fields_annotations->at(i); 2609 if (field_annotations == NULL || field_annotations->length() == 0) { 2610 // this field does not have any annotations so skip it 2611 continue; 2612 } 2613 2614 int byte_i = 0; // byte index into field_annotations 2615 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i)) { 2616 log_debug(redefine, class, annotation)("bad field_annotations at %d", i); 2617 // propagate failure back to caller 2618 return false; 2619 } 2620 } 2621 2622 return true; 2623 } // end rewrite_cp_refs_in_fields_annotations() 2624 2625 2626 // Rewrite constant pool references in a methods_annotations field. 2627 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations( 2628 InstanceKlass* scratch_class) { 2629 2630 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2631 Method* m = scratch_class->methods()->at(i); 2632 AnnotationArray* method_annotations = m->constMethod()->method_annotations(); 2633 2634 if (method_annotations == NULL || method_annotations->length() == 0) { 2635 // this method does not have any annotations so skip it 2636 continue; 2637 } 2638 2639 int byte_i = 0; // byte index into method_annotations 2640 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i)) { 2641 log_debug(redefine, class, annotation)("bad method_annotations at %d", i); 2642 // propagate failure back to caller 2643 return false; 2644 } 2645 } 2646 2647 return true; 2648 } // end rewrite_cp_refs_in_methods_annotations() 2649 2650 2651 // Rewrite constant pool references in a methods_parameter_annotations 2652 // field. This "structure" is adapted from the 2653 // RuntimeVisibleParameterAnnotations_attribute described in section 2654 // 4.8.17 of the 2nd-edition of the VM spec: 2655 // 2656 // methods_parameter_annotations_typeArray { 2657 // u1 num_parameters; 2658 // { 2659 // u2 num_annotations; 2660 // annotation annotations[num_annotations]; 2661 // } parameter_annotations[num_parameters]; 2662 // } 2663 // 2664 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations( 2665 InstanceKlass* scratch_class) { 2666 2667 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2668 Method* m = scratch_class->methods()->at(i); 2669 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations(); 2670 if (method_parameter_annotations == NULL 2671 || method_parameter_annotations->length() == 0) { 2672 // this method does not have any parameter annotations so skip it 2673 continue; 2674 } 2675 2676 if (method_parameter_annotations->length() < 1) { 2677 // not enough room for a num_parameters field 2678 log_debug(redefine, class, annotation)("length() is too small for a num_parameters field at %d", i); 2679 return false; 2680 } 2681 2682 int byte_i = 0; // byte index into method_parameter_annotations 2683 2684 u1 num_parameters = method_parameter_annotations->at(byte_i); 2685 byte_i++; 2686 2687 log_debug(redefine, class, annotation)("num_parameters=%d", num_parameters); 2688 2689 int calc_num_parameters = 0; 2690 for (; calc_num_parameters < num_parameters; calc_num_parameters++) { 2691 if (!rewrite_cp_refs_in_annotations_typeArray(method_parameter_annotations, byte_i)) { 2692 log_debug(redefine, class, annotation)("bad method_parameter_annotations at %d", calc_num_parameters); 2693 // propagate failure back to caller 2694 return false; 2695 } 2696 } 2697 assert(num_parameters == calc_num_parameters, "sanity check"); 2698 } 2699 2700 return true; 2701 } // end rewrite_cp_refs_in_methods_parameter_annotations() 2702 2703 2704 // Rewrite constant pool references in a methods_default_annotations 2705 // field. This "structure" is adapted from the AnnotationDefault_attribute 2706 // that is described in section 4.8.19 of the 2nd-edition of the VM spec: 2707 // 2708 // methods_default_annotations_typeArray { 2709 // element_value default_value; 2710 // } 2711 // 2712 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations( 2713 InstanceKlass* scratch_class) { 2714 2715 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2716 Method* m = scratch_class->methods()->at(i); 2717 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations(); 2718 if (method_default_annotations == NULL 2719 || method_default_annotations->length() == 0) { 2720 // this method does not have any default annotations so skip it 2721 continue; 2722 } 2723 2724 int byte_i = 0; // byte index into method_default_annotations 2725 2726 if (!rewrite_cp_refs_in_element_value( 2727 method_default_annotations, byte_i)) { 2728 log_debug(redefine, class, annotation)("bad default element_value at %d", i); 2729 // propagate failure back to caller 2730 return false; 2731 } 2732 } 2733 2734 return true; 2735 } // end rewrite_cp_refs_in_methods_default_annotations() 2736 2737 2738 // Rewrite constant pool references in a class_type_annotations field. 2739 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations( 2740 InstanceKlass* scratch_class) { 2741 2742 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations(); 2743 if (class_type_annotations == NULL || class_type_annotations->length() == 0) { 2744 // no class_type_annotations so nothing to do 2745 return true; 2746 } 2747 2748 log_debug(redefine, class, annotation)("class_type_annotations length=%d", class_type_annotations->length()); 2749 2750 int byte_i = 0; // byte index into class_type_annotations 2751 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations, 2752 byte_i, "ClassFile"); 2753 } // end rewrite_cp_refs_in_class_type_annotations() 2754 2755 2756 // Rewrite constant pool references in a fields_type_annotations field. 2757 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations(InstanceKlass* scratch_class) { 2758 2759 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations(); 2760 if (fields_type_annotations == NULL || fields_type_annotations->length() == 0) { 2761 // no fields_type_annotations so nothing to do 2762 return true; 2763 } 2764 2765 log_debug(redefine, class, annotation)("fields_type_annotations length=%d", fields_type_annotations->length()); 2766 2767 for (int i = 0; i < fields_type_annotations->length(); i++) { 2768 AnnotationArray* field_type_annotations = fields_type_annotations->at(i); 2769 if (field_type_annotations == NULL || field_type_annotations->length() == 0) { 2770 // this field does not have any annotations so skip it 2771 continue; 2772 } 2773 2774 int byte_i = 0; // byte index into field_type_annotations 2775 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations, 2776 byte_i, "field_info")) { 2777 log_debug(redefine, class, annotation)("bad field_type_annotations at %d", i); 2778 // propagate failure back to caller 2779 return false; 2780 } 2781 } 2782 2783 return true; 2784 } // end rewrite_cp_refs_in_fields_type_annotations() 2785 2786 2787 // Rewrite constant pool references in a methods_type_annotations field. 2788 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations( 2789 InstanceKlass* scratch_class) { 2790 2791 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2792 Method* m = scratch_class->methods()->at(i); 2793 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations(); 2794 2795 if (method_type_annotations == NULL || method_type_annotations->length() == 0) { 2796 // this method does not have any annotations so skip it 2797 continue; 2798 } 2799 2800 log_debug(redefine, class, annotation)("methods type_annotations length=%d", method_type_annotations->length()); 2801 2802 int byte_i = 0; // byte index into method_type_annotations 2803 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations, 2804 byte_i, "method_info")) { 2805 log_debug(redefine, class, annotation)("bad method_type_annotations at %d", i); 2806 // propagate failure back to caller 2807 return false; 2808 } 2809 } 2810 2811 return true; 2812 } // end rewrite_cp_refs_in_methods_type_annotations() 2813 2814 2815 // Rewrite constant pool references in a type_annotations 2816 // field. This "structure" is adapted from the 2817 // RuntimeVisibleTypeAnnotations_attribute described in 2818 // section 4.7.20 of the Java SE 8 Edition of the VM spec: 2819 // 2820 // type_annotations_typeArray { 2821 // u2 num_annotations; 2822 // type_annotation annotations[num_annotations]; 2823 // } 2824 // 2825 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray( 2826 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2827 const char * location_mesg) { 2828 2829 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2830 // not enough room for num_annotations field 2831 log_debug(redefine, class, annotation)("length() is too small for num_annotations field"); 2832 return false; 2833 } 2834 2835 u2 num_annotations = Bytes::get_Java_u2((address) 2836 type_annotations_typeArray->adr_at(byte_i_ref)); 2837 byte_i_ref += 2; 2838 2839 log_debug(redefine, class, annotation)("num_type_annotations=%d", num_annotations); 2840 2841 int calc_num_annotations = 0; 2842 for (; calc_num_annotations < num_annotations; calc_num_annotations++) { 2843 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray, 2844 byte_i_ref, location_mesg)) { 2845 log_debug(redefine, class, annotation)("bad type_annotation_struct at %d", calc_num_annotations); 2846 // propagate failure back to caller 2847 return false; 2848 } 2849 } 2850 assert(num_annotations == calc_num_annotations, "sanity check"); 2851 2852 if (byte_i_ref != type_annotations_typeArray->length()) { 2853 log_debug(redefine, class, annotation) 2854 ("read wrong amount of bytes at end of processing type_annotations_typeArray (%d of %d bytes were read)", 2855 byte_i_ref, type_annotations_typeArray->length()); 2856 return false; 2857 } 2858 2859 return true; 2860 } // end rewrite_cp_refs_in_type_annotations_typeArray() 2861 2862 2863 // Rewrite constant pool references in a type_annotation 2864 // field. This "structure" is adapted from the 2865 // RuntimeVisibleTypeAnnotations_attribute described in 2866 // section 4.7.20 of the Java SE 8 Edition of the VM spec: 2867 // 2868 // type_annotation { 2869 // u1 target_type; 2870 // union { 2871 // type_parameter_target; 2872 // supertype_target; 2873 // type_parameter_bound_target; 2874 // empty_target; 2875 // method_formal_parameter_target; 2876 // throws_target; 2877 // localvar_target; 2878 // catch_target; 2879 // offset_target; 2880 // type_argument_target; 2881 // } target_info; 2882 // type_path target_path; 2883 // annotation anno; 2884 // } 2885 // 2886 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct( 2887 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2888 const char * location_mesg) { 2889 2890 if (!skip_type_annotation_target(type_annotations_typeArray, 2891 byte_i_ref, location_mesg)) { 2892 return false; 2893 } 2894 2895 if (!skip_type_annotation_type_path(type_annotations_typeArray, byte_i_ref)) { 2896 return false; 2897 } 2898 2899 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray, byte_i_ref)) { 2900 return false; 2901 } 2902 2903 return true; 2904 } // end rewrite_cp_refs_in_type_annotation_struct() 2905 2906 2907 // Read, verify and skip over the target_type and target_info part 2908 // so that rewriting can continue in the later parts of the struct. 2909 // 2910 // u1 target_type; 2911 // union { 2912 // type_parameter_target; 2913 // supertype_target; 2914 // type_parameter_bound_target; 2915 // empty_target; 2916 // method_formal_parameter_target; 2917 // throws_target; 2918 // localvar_target; 2919 // catch_target; 2920 // offset_target; 2921 // type_argument_target; 2922 // } target_info; 2923 // 2924 bool VM_RedefineClasses::skip_type_annotation_target( 2925 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2926 const char * location_mesg) { 2927 2928 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2929 // not enough room for a target_type let alone the rest of a type_annotation 2930 log_debug(redefine, class, annotation)("length() is too small for a target_type"); 2931 return false; 2932 } 2933 2934 u1 target_type = type_annotations_typeArray->at(byte_i_ref); 2935 byte_i_ref += 1; 2936 log_debug(redefine, class, annotation)("target_type=0x%.2x", target_type); 2937 log_debug(redefine, class, annotation)("location=%s", location_mesg); 2938 2939 // Skip over target_info 2940 switch (target_type) { 2941 case 0x00: 2942 // kind: type parameter declaration of generic class or interface 2943 // location: ClassFile 2944 case 0x01: 2945 // kind: type parameter declaration of generic method or constructor 2946 // location: method_info 2947 2948 { 2949 // struct: 2950 // type_parameter_target { 2951 // u1 type_parameter_index; 2952 // } 2953 // 2954 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2955 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_target"); 2956 return false; 2957 } 2958 2959 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2960 byte_i_ref += 1; 2961 2962 log_debug(redefine, class, annotation)("type_parameter_target: type_parameter_index=%d", type_parameter_index); 2963 } break; 2964 2965 case 0x10: 2966 // kind: type in extends clause of class or interface declaration 2967 // or in implements clause of interface declaration 2968 // location: ClassFile 2969 2970 { 2971 // struct: 2972 // supertype_target { 2973 // u2 supertype_index; 2974 // } 2975 // 2976 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2977 log_debug(redefine, class, annotation)("length() is too small for a supertype_target"); 2978 return false; 2979 } 2980 2981 u2 supertype_index = Bytes::get_Java_u2((address) 2982 type_annotations_typeArray->adr_at(byte_i_ref)); 2983 byte_i_ref += 2; 2984 2985 log_debug(redefine, class, annotation)("supertype_target: supertype_index=%d", supertype_index); 2986 } break; 2987 2988 case 0x11: 2989 // kind: type in bound of type parameter declaration of generic class or interface 2990 // location: ClassFile 2991 case 0x12: 2992 // kind: type in bound of type parameter declaration of generic method or constructor 2993 // location: method_info 2994 2995 { 2996 // struct: 2997 // type_parameter_bound_target { 2998 // u1 type_parameter_index; 2999 // u1 bound_index; 3000 // } 3001 // 3002 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 3003 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_bound_target"); 3004 return false; 3005 } 3006 3007 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref); 3008 byte_i_ref += 1; 3009 u1 bound_index = type_annotations_typeArray->at(byte_i_ref); 3010 byte_i_ref += 1; 3011 3012 log_debug(redefine, class, annotation) 3013 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d", type_parameter_index, bound_index); 3014 } break; 3015 3016 case 0x13: 3017 // kind: type in field declaration 3018 // location: field_info 3019 case 0x14: 3020 // kind: return type of method, or type of newly constructed object 3021 // location: method_info 3022 case 0x15: 3023 // kind: receiver type of method or constructor 3024 // location: method_info 3025 3026 { 3027 // struct: 3028 // empty_target { 3029 // } 3030 // 3031 log_debug(redefine, class, annotation)("empty_target"); 3032 } break; 3033 3034 case 0x16: 3035 // kind: type in formal parameter declaration of method, constructor, or lambda expression 3036 // location: method_info 3037 3038 { 3039 // struct: 3040 // formal_parameter_target { 3041 // u1 formal_parameter_index; 3042 // } 3043 // 3044 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 3045 log_debug(redefine, class, annotation)("length() is too small for a formal_parameter_target"); 3046 return false; 3047 } 3048 3049 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref); 3050 byte_i_ref += 1; 3051 3052 log_debug(redefine, class, annotation) 3053 ("formal_parameter_target: formal_parameter_index=%d", formal_parameter_index); 3054 } break; 3055 3056 case 0x17: 3057 // kind: type in throws clause of method or constructor 3058 // location: method_info 3059 3060 { 3061 // struct: 3062 // throws_target { 3063 // u2 throws_type_index 3064 // } 3065 // 3066 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 3067 log_debug(redefine, class, annotation)("length() is too small for a throws_target"); 3068 return false; 3069 } 3070 3071 u2 throws_type_index = Bytes::get_Java_u2((address) 3072 type_annotations_typeArray->adr_at(byte_i_ref)); 3073 byte_i_ref += 2; 3074 3075 log_debug(redefine, class, annotation)("throws_target: throws_type_index=%d", throws_type_index); 3076 } break; 3077 3078 case 0x40: 3079 // kind: type in local variable declaration 3080 // location: Code 3081 case 0x41: 3082 // kind: type in resource variable declaration 3083 // location: Code 3084 3085 { 3086 // struct: 3087 // localvar_target { 3088 // u2 table_length; 3089 // struct { 3090 // u2 start_pc; 3091 // u2 length; 3092 // u2 index; 3093 // } table[table_length]; 3094 // } 3095 // 3096 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 3097 // not enough room for a table_length let alone the rest of a localvar_target 3098 log_debug(redefine, class, annotation)("length() is too small for a localvar_target table_length"); 3099 return false; 3100 } 3101 3102 u2 table_length = Bytes::get_Java_u2((address) 3103 type_annotations_typeArray->adr_at(byte_i_ref)); 3104 byte_i_ref += 2; 3105 3106 log_debug(redefine, class, annotation)("localvar_target: table_length=%d", table_length); 3107 3108 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry 3109 int table_size = table_length * table_struct_size; 3110 3111 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) { 3112 // not enough room for a table 3113 log_debug(redefine, class, annotation)("length() is too small for a table array of length %d", table_length); 3114 return false; 3115 } 3116 3117 // Skip over table 3118 byte_i_ref += table_size; 3119 } break; 3120 3121 case 0x42: 3122 // kind: type in exception parameter declaration 3123 // location: Code 3124 3125 { 3126 // struct: 3127 // catch_target { 3128 // u2 exception_table_index; 3129 // } 3130 // 3131 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 3132 log_debug(redefine, class, annotation)("length() is too small for a catch_target"); 3133 return false; 3134 } 3135 3136 u2 exception_table_index = Bytes::get_Java_u2((address) 3137 type_annotations_typeArray->adr_at(byte_i_ref)); 3138 byte_i_ref += 2; 3139 3140 log_debug(redefine, class, annotation)("catch_target: exception_table_index=%d", exception_table_index); 3141 } break; 3142 3143 case 0x43: 3144 // kind: type in instanceof expression 3145 // location: Code 3146 case 0x44: 3147 // kind: type in new expression 3148 // location: Code 3149 case 0x45: 3150 // kind: type in method reference expression using ::new 3151 // location: Code 3152 case 0x46: 3153 // kind: type in method reference expression using ::Identifier 3154 // location: Code 3155 3156 { 3157 // struct: 3158 // offset_target { 3159 // u2 offset; 3160 // } 3161 // 3162 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 3163 log_debug(redefine, class, annotation)("length() is too small for a offset_target"); 3164 return false; 3165 } 3166 3167 u2 offset = Bytes::get_Java_u2((address) 3168 type_annotations_typeArray->adr_at(byte_i_ref)); 3169 byte_i_ref += 2; 3170 3171 log_debug(redefine, class, annotation)("offset_target: offset=%d", offset); 3172 } break; 3173 3174 case 0x47: 3175 // kind: type in cast expression 3176 // location: Code 3177 case 0x48: 3178 // kind: type argument for generic constructor in new expression or 3179 // explicit constructor invocation statement 3180 // location: Code 3181 case 0x49: 3182 // kind: type argument for generic method in method invocation expression 3183 // location: Code 3184 case 0x4A: 3185 // kind: type argument for generic constructor in method reference expression using ::new 3186 // location: Code 3187 case 0x4B: 3188 // kind: type argument for generic method in method reference expression using ::Identifier 3189 // location: Code 3190 3191 { 3192 // struct: 3193 // type_argument_target { 3194 // u2 offset; 3195 // u1 type_argument_index; 3196 // } 3197 // 3198 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) { 3199 log_debug(redefine, class, annotation)("length() is too small for a type_argument_target"); 3200 return false; 3201 } 3202 3203 u2 offset = Bytes::get_Java_u2((address) 3204 type_annotations_typeArray->adr_at(byte_i_ref)); 3205 byte_i_ref += 2; 3206 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref); 3207 byte_i_ref += 1; 3208 3209 log_debug(redefine, class, annotation) 3210 ("type_argument_target: offset=%d, type_argument_index=%d", offset, type_argument_index); 3211 } break; 3212 3213 default: 3214 log_debug(redefine, class, annotation)("unknown target_type"); 3215 #ifdef ASSERT 3216 ShouldNotReachHere(); 3217 #endif 3218 return false; 3219 } 3220 3221 return true; 3222 } // end skip_type_annotation_target() 3223 3224 3225 // Read, verify and skip over the type_path part so that rewriting 3226 // can continue in the later parts of the struct. 3227 // 3228 // type_path { 3229 // u1 path_length; 3230 // { 3231 // u1 type_path_kind; 3232 // u1 type_argument_index; 3233 // } path[path_length]; 3234 // } 3235 // 3236 bool VM_RedefineClasses::skip_type_annotation_type_path( 3237 AnnotationArray* type_annotations_typeArray, int &byte_i_ref) { 3238 3239 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 3240 // not enough room for a path_length let alone the rest of the type_path 3241 log_debug(redefine, class, annotation)("length() is too small for a type_path"); 3242 return false; 3243 } 3244 3245 u1 path_length = type_annotations_typeArray->at(byte_i_ref); 3246 byte_i_ref += 1; 3247 3248 log_debug(redefine, class, annotation)("type_path: path_length=%d", path_length); 3249 3250 int calc_path_length = 0; 3251 for (; calc_path_length < path_length; calc_path_length++) { 3252 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) { 3253 // not enough room for a path 3254 log_debug(redefine, class, annotation) 3255 ("length() is too small for path entry %d of %d", calc_path_length, path_length); 3256 return false; 3257 } 3258 3259 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref); 3260 byte_i_ref += 1; 3261 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref); 3262 byte_i_ref += 1; 3263 3264 log_debug(redefine, class, annotation) 3265 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d", 3266 calc_path_length, type_path_kind, type_argument_index); 3267 3268 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) { 3269 // not enough room for a path 3270 log_debug(redefine, class, annotation)("inconsistent type_path values"); 3271 return false; 3272 } 3273 } 3274 assert(path_length == calc_path_length, "sanity check"); 3275 3276 return true; 3277 } // end skip_type_annotation_type_path() 3278 3279 3280 // Rewrite constant pool references in the method's stackmap table. 3281 // These "structures" are adapted from the StackMapTable_attribute that 3282 // is described in section 4.8.4 of the 6.0 version of the VM spec 3283 // (dated 2005.10.26): 3284 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf 3285 // 3286 // stack_map { 3287 // u2 number_of_entries; 3288 // stack_map_frame entries[number_of_entries]; 3289 // } 3290 // 3291 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table( 3292 const methodHandle& method) { 3293 3294 if (!method->has_stackmap_table()) { 3295 return; 3296 } 3297 3298 AnnotationArray* stackmap_data = method->stackmap_data(); 3299 address stackmap_p = (address)stackmap_data->adr_at(0); 3300 address stackmap_end = stackmap_p + stackmap_data->length(); 3301 3302 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries"); 3303 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p); 3304 stackmap_p += 2; 3305 3306 log_debug(redefine, class, stackmap)("number_of_entries=%u", number_of_entries); 3307 3308 // walk through each stack_map_frame 3309 u2 calc_number_of_entries = 0; 3310 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) { 3311 // The stack_map_frame structure is a u1 frame_type followed by 3312 // 0 or more bytes of data: 3313 // 3314 // union stack_map_frame { 3315 // same_frame; 3316 // same_locals_1_stack_item_frame; 3317 // same_locals_1_stack_item_frame_extended; 3318 // chop_frame; 3319 // same_frame_extended; 3320 // append_frame; 3321 // full_frame; 3322 // } 3323 3324 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type"); 3325 u1 frame_type = *stackmap_p; 3326 stackmap_p++; 3327 3328 // same_frame { 3329 // u1 frame_type = SAME; /* 0-63 */ 3330 // } 3331 if (frame_type <= 63) { 3332 // nothing more to do for same_frame 3333 } 3334 3335 // same_locals_1_stack_item_frame { 3336 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */ 3337 // verification_type_info stack[1]; 3338 // } 3339 else if (frame_type >= 64 && frame_type <= 127) { 3340 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3341 calc_number_of_entries, frame_type); 3342 } 3343 3344 // reserved for future use 3345 else if (frame_type >= 128 && frame_type <= 246) { 3346 // nothing more to do for reserved frame_types 3347 } 3348 3349 // same_locals_1_stack_item_frame_extended { 3350 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */ 3351 // u2 offset_delta; 3352 // verification_type_info stack[1]; 3353 // } 3354 else if (frame_type == 247) { 3355 stackmap_p += 2; 3356 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3357 calc_number_of_entries, frame_type); 3358 } 3359 3360 // chop_frame { 3361 // u1 frame_type = CHOP; /* 248-250 */ 3362 // u2 offset_delta; 3363 // } 3364 else if (frame_type >= 248 && frame_type <= 250) { 3365 stackmap_p += 2; 3366 } 3367 3368 // same_frame_extended { 3369 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/ 3370 // u2 offset_delta; 3371 // } 3372 else if (frame_type == 251) { 3373 stackmap_p += 2; 3374 } 3375 3376 // append_frame { 3377 // u1 frame_type = APPEND; /* 252-254 */ 3378 // u2 offset_delta; 3379 // verification_type_info locals[frame_type - 251]; 3380 // } 3381 else if (frame_type >= 252 && frame_type <= 254) { 3382 assert(stackmap_p + 2 <= stackmap_end, 3383 "no room for offset_delta"); 3384 stackmap_p += 2; 3385 u1 len = frame_type - 251; 3386 for (u1 i = 0; i < len; i++) { 3387 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3388 calc_number_of_entries, frame_type); 3389 } 3390 } 3391 3392 // full_frame { 3393 // u1 frame_type = FULL_FRAME; /* 255 */ 3394 // u2 offset_delta; 3395 // u2 number_of_locals; 3396 // verification_type_info locals[number_of_locals]; 3397 // u2 number_of_stack_items; 3398 // verification_type_info stack[number_of_stack_items]; 3399 // } 3400 else if (frame_type == 255) { 3401 assert(stackmap_p + 2 + 2 <= stackmap_end, 3402 "no room for smallest full_frame"); 3403 stackmap_p += 2; 3404 3405 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p); 3406 stackmap_p += 2; 3407 3408 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) { 3409 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3410 calc_number_of_entries, frame_type); 3411 } 3412 3413 // Use the largest size for the number_of_stack_items, but only get 3414 // the right number of bytes. 3415 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p); 3416 stackmap_p += 2; 3417 3418 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) { 3419 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3420 calc_number_of_entries, frame_type); 3421 } 3422 } 3423 } // end while there is a stack_map_frame 3424 assert(number_of_entries == calc_number_of_entries, "sanity check"); 3425 } // end rewrite_cp_refs_in_stack_map_table() 3426 3427 3428 // Rewrite constant pool references in the verification type info 3429 // portion of the method's stackmap table. These "structures" are 3430 // adapted from the StackMapTable_attribute that is described in 3431 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26): 3432 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf 3433 // 3434 // The verification_type_info structure is a u1 tag followed by 0 or 3435 // more bytes of data: 3436 // 3437 // union verification_type_info { 3438 // Top_variable_info; 3439 // Integer_variable_info; 3440 // Float_variable_info; 3441 // Long_variable_info; 3442 // Double_variable_info; 3443 // Null_variable_info; 3444 // UninitializedThis_variable_info; 3445 // Object_variable_info; 3446 // Uninitialized_variable_info; 3447 // } 3448 // 3449 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info( 3450 address& stackmap_p_ref, address stackmap_end, u2 frame_i, 3451 u1 frame_type) { 3452 3453 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag"); 3454 u1 tag = *stackmap_p_ref; 3455 stackmap_p_ref++; 3456 3457 switch (tag) { 3458 // Top_variable_info { 3459 // u1 tag = ITEM_Top; /* 0 */ 3460 // } 3461 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top 3462 case 0: // fall through 3463 3464 // Integer_variable_info { 3465 // u1 tag = ITEM_Integer; /* 1 */ 3466 // } 3467 case ITEM_Integer: // fall through 3468 3469 // Float_variable_info { 3470 // u1 tag = ITEM_Float; /* 2 */ 3471 // } 3472 case ITEM_Float: // fall through 3473 3474 // Double_variable_info { 3475 // u1 tag = ITEM_Double; /* 3 */ 3476 // } 3477 case ITEM_Double: // fall through 3478 3479 // Long_variable_info { 3480 // u1 tag = ITEM_Long; /* 4 */ 3481 // } 3482 case ITEM_Long: // fall through 3483 3484 // Null_variable_info { 3485 // u1 tag = ITEM_Null; /* 5 */ 3486 // } 3487 case ITEM_Null: // fall through 3488 3489 // UninitializedThis_variable_info { 3490 // u1 tag = ITEM_UninitializedThis; /* 6 */ 3491 // } 3492 case ITEM_UninitializedThis: 3493 // nothing more to do for the above tag types 3494 break; 3495 3496 // Object_variable_info { 3497 // u1 tag = ITEM_Object; /* 7 */ 3498 // u2 cpool_index; 3499 // } 3500 case ITEM_Object: 3501 { 3502 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index"); 3503 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref); 3504 u2 new_cp_index = find_new_index(cpool_index); 3505 if (new_cp_index != 0) { 3506 log_debug(redefine, class, stackmap)("mapped old cpool_index=%d", cpool_index); 3507 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index); 3508 cpool_index = new_cp_index; 3509 } 3510 stackmap_p_ref += 2; 3511 3512 log_debug(redefine, class, stackmap) 3513 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i, frame_type, cpool_index); 3514 } break; 3515 3516 // Uninitialized_variable_info { 3517 // u1 tag = ITEM_Uninitialized; /* 8 */ 3518 // u2 offset; 3519 // } 3520 case ITEM_Uninitialized: 3521 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset"); 3522 stackmap_p_ref += 2; 3523 break; 3524 3525 default: 3526 log_debug(redefine, class, stackmap)("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag); 3527 ShouldNotReachHere(); 3528 break; 3529 } // end switch (tag) 3530 } // end rewrite_cp_refs_in_verification_type_info() 3531 3532 3533 // Change the constant pool associated with klass scratch_class to 3534 // scratch_cp. If shrink is true, then scratch_cp_length elements 3535 // are copied from scratch_cp to a smaller constant pool and the 3536 // smaller constant pool is associated with scratch_class. 3537 void VM_RedefineClasses::set_new_constant_pool( 3538 ClassLoaderData* loader_data, 3539 InstanceKlass* scratch_class, constantPoolHandle scratch_cp, 3540 int scratch_cp_length, TRAPS) { 3541 assert(scratch_cp->length() >= scratch_cp_length, "sanity check"); 3542 3543 // scratch_cp is a merged constant pool and has enough space for a 3544 // worst case merge situation. We want to associate the minimum 3545 // sized constant pool with the klass to save space. 3546 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK); 3547 constantPoolHandle smaller_cp(THREAD, cp); 3548 3549 // preserve version() value in the smaller copy 3550 int version = scratch_cp->version(); 3551 assert(version != 0, "sanity check"); 3552 smaller_cp->set_version(version); 3553 3554 // attach klass to new constant pool 3555 // reference to the cp holder is needed for copy_operands() 3556 smaller_cp->set_pool_holder(scratch_class); 3557 3558 smaller_cp->copy_fields(scratch_cp()); 3559 3560 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD); 3561 if (HAS_PENDING_EXCEPTION) { 3562 // Exception is handled in the caller 3563 loader_data->add_to_deallocate_list(smaller_cp()); 3564 return; 3565 } 3566 scratch_cp = smaller_cp; 3567 3568 // attach new constant pool to klass 3569 scratch_class->set_constants(scratch_cp()); 3570 scratch_cp->initialize_unresolved_klasses(loader_data, CHECK); 3571 3572 int i; // for portability 3573 3574 // update each field in klass to use new constant pool indices as needed 3575 for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) { 3576 jshort cur_index = fs.name_index(); 3577 jshort new_index = find_new_index(cur_index); 3578 if (new_index != 0) { 3579 log_trace(redefine, class, constantpool)("field-name_index change: %d to %d", cur_index, new_index); 3580 fs.set_name_index(new_index); 3581 } 3582 cur_index = fs.signature_index(); 3583 new_index = find_new_index(cur_index); 3584 if (new_index != 0) { 3585 log_trace(redefine, class, constantpool)("field-signature_index change: %d to %d", cur_index, new_index); 3586 fs.set_signature_index(new_index); 3587 } 3588 cur_index = fs.initval_index(); 3589 new_index = find_new_index(cur_index); 3590 if (new_index != 0) { 3591 log_trace(redefine, class, constantpool)("field-initval_index change: %d to %d", cur_index, new_index); 3592 fs.set_initval_index(new_index); 3593 } 3594 cur_index = fs.generic_signature_index(); 3595 new_index = find_new_index(cur_index); 3596 if (new_index != 0) { 3597 log_trace(redefine, class, constantpool)("field-generic_signature change: %d to %d", cur_index, new_index); 3598 fs.set_generic_signature_index(new_index); 3599 } 3600 } // end for each field 3601 3602 // Update constant pool indices in the inner classes info to use 3603 // new constant indices as needed. The inner classes info is a 3604 // quadruple: 3605 // (inner_class_info, outer_class_info, inner_name, inner_access_flags) 3606 InnerClassesIterator iter(scratch_class); 3607 for (; !iter.done(); iter.next()) { 3608 int cur_index = iter.inner_class_info_index(); 3609 if (cur_index == 0) { 3610 continue; // JVM spec. allows null inner class refs so skip it 3611 } 3612 int new_index = find_new_index(cur_index); 3613 if (new_index != 0) { 3614 log_trace(redefine, class, constantpool)("inner_class_info change: %d to %d", cur_index, new_index); 3615 iter.set_inner_class_info_index(new_index); 3616 } 3617 cur_index = iter.outer_class_info_index(); 3618 new_index = find_new_index(cur_index); 3619 if (new_index != 0) { 3620 log_trace(redefine, class, constantpool)("outer_class_info change: %d to %d", cur_index, new_index); 3621 iter.set_outer_class_info_index(new_index); 3622 } 3623 cur_index = iter.inner_name_index(); 3624 new_index = find_new_index(cur_index); 3625 if (new_index != 0) { 3626 log_trace(redefine, class, constantpool)("inner_name change: %d to %d", cur_index, new_index); 3627 iter.set_inner_name_index(new_index); 3628 } 3629 } // end for each inner class 3630 3631 // Attach each method in klass to the new constant pool and update 3632 // to use new constant pool indices as needed: 3633 Array<Method*>* methods = scratch_class->methods(); 3634 for (i = methods->length() - 1; i >= 0; i--) { 3635 methodHandle method(THREAD, methods->at(i)); 3636 method->set_constants(scratch_cp()); 3637 3638 int new_index = find_new_index(method->name_index()); 3639 if (new_index != 0) { 3640 log_trace(redefine, class, constantpool) 3641 ("method-name_index change: %d to %d", method->name_index(), new_index); 3642 method->set_name_index(new_index); 3643 } 3644 new_index = find_new_index(method->signature_index()); 3645 if (new_index != 0) { 3646 log_trace(redefine, class, constantpool) 3647 ("method-signature_index change: %d to %d", method->signature_index(), new_index); 3648 method->set_signature_index(new_index); 3649 } 3650 new_index = find_new_index(method->generic_signature_index()); 3651 if (new_index != 0) { 3652 log_trace(redefine, class, constantpool) 3653 ("method-generic_signature_index change: %d to %d", method->generic_signature_index(), new_index); 3654 method->set_generic_signature_index(new_index); 3655 } 3656 3657 // Update constant pool indices in the method's checked exception 3658 // table to use new constant indices as needed. 3659 int cext_length = method->checked_exceptions_length(); 3660 if (cext_length > 0) { 3661 CheckedExceptionElement * cext_table = 3662 method->checked_exceptions_start(); 3663 for (int j = 0; j < cext_length; j++) { 3664 int cur_index = cext_table[j].class_cp_index; 3665 int new_index = find_new_index(cur_index); 3666 if (new_index != 0) { 3667 log_trace(redefine, class, constantpool)("cext-class_cp_index change: %d to %d", cur_index, new_index); 3668 cext_table[j].class_cp_index = (u2)new_index; 3669 } 3670 } // end for each checked exception table entry 3671 } // end if there are checked exception table entries 3672 3673 // Update each catch type index in the method's exception table 3674 // to use new constant pool indices as needed. The exception table 3675 // holds quadruple entries of the form: 3676 // (beg_bci, end_bci, handler_bci, klass_index) 3677 3678 ExceptionTable ex_table(method()); 3679 int ext_length = ex_table.length(); 3680 3681 for (int j = 0; j < ext_length; j ++) { 3682 int cur_index = ex_table.catch_type_index(j); 3683 int new_index = find_new_index(cur_index); 3684 if (new_index != 0) { 3685 log_trace(redefine, class, constantpool)("ext-klass_index change: %d to %d", cur_index, new_index); 3686 ex_table.set_catch_type_index(j, new_index); 3687 } 3688 } // end for each exception table entry 3689 3690 // Update constant pool indices in the method's local variable 3691 // table to use new constant indices as needed. The local variable 3692 // table hold sextuple entries of the form: 3693 // (start_pc, length, name_index, descriptor_index, signature_index, slot) 3694 int lvt_length = method->localvariable_table_length(); 3695 if (lvt_length > 0) { 3696 LocalVariableTableElement * lv_table = 3697 method->localvariable_table_start(); 3698 for (int j = 0; j < lvt_length; j++) { 3699 int cur_index = lv_table[j].name_cp_index; 3700 int new_index = find_new_index(cur_index); 3701 if (new_index != 0) { 3702 log_trace(redefine, class, constantpool)("lvt-name_cp_index change: %d to %d", cur_index, new_index); 3703 lv_table[j].name_cp_index = (u2)new_index; 3704 } 3705 cur_index = lv_table[j].descriptor_cp_index; 3706 new_index = find_new_index(cur_index); 3707 if (new_index != 0) { 3708 log_trace(redefine, class, constantpool)("lvt-descriptor_cp_index change: %d to %d", cur_index, new_index); 3709 lv_table[j].descriptor_cp_index = (u2)new_index; 3710 } 3711 cur_index = lv_table[j].signature_cp_index; 3712 new_index = find_new_index(cur_index); 3713 if (new_index != 0) { 3714 log_trace(redefine, class, constantpool)("lvt-signature_cp_index change: %d to %d", cur_index, new_index); 3715 lv_table[j].signature_cp_index = (u2)new_index; 3716 } 3717 } // end for each local variable table entry 3718 } // end if there are local variable table entries 3719 3720 // Update constant pool indices in the method's method_parameters. 3721 int mp_length = method->method_parameters_length(); 3722 if (mp_length > 0) { 3723 MethodParametersElement* elem = method->method_parameters_start(); 3724 for (int j = 0; j < mp_length; j++) { 3725 const int cp_index = elem[j].name_cp_index; 3726 const int new_cp_index = find_new_index(cp_index); 3727 if (new_cp_index != 0) { 3728 elem[j].name_cp_index = (u2)new_cp_index; 3729 } 3730 } 3731 } 3732 3733 rewrite_cp_refs_in_stack_map_table(method); 3734 } // end for each method 3735 } // end set_new_constant_pool() 3736 3737 3738 // Unevolving classes may point to methods of the_class directly 3739 // from their constant pool caches, itables, and/or vtables. We 3740 // use the ClassLoaderDataGraph::classes_do() facility and this helper 3741 // to fix up these pointers. MethodData also points to old methods and 3742 // must be cleaned. 3743 3744 // Adjust cpools and vtables closure 3745 void VM_RedefineClasses::AdjustAndCleanMetadata::do_klass(Klass* k) { 3746 3747 // This is a very busy routine. We don't want too much tracing 3748 // printed out. 3749 bool trace_name_printed = false; 3750 3751 // If the class being redefined is java.lang.Object, we need to fix all 3752 // array class vtables also. The _has_redefined_Object flag is global. 3753 // Once the java.lang.Object has been redefined (by the current or one 3754 // of the previous VM_RedefineClasses operations) we have to always 3755 // adjust method entries for array classes. 3756 if (k->is_array_klass() && _has_redefined_Object) { 3757 k->vtable().adjust_method_entries(&trace_name_printed); 3758 3759 } else if (k->is_instance_klass()) { 3760 HandleMark hm(_thread); 3761 InstanceKlass *ik = InstanceKlass::cast(k); 3762 3763 // Clean MethodData of this class's methods so they don't refer to 3764 // old methods that are no longer running. 3765 Array<Method*>* methods = ik->methods(); 3766 int num_methods = methods->length(); 3767 for (int index = 0; index < num_methods; ++index) { 3768 if (methods->at(index)->method_data() != NULL) { 3769 methods->at(index)->method_data()->clean_weak_method_links(); 3770 } 3771 } 3772 3773 // Adjust all vtables, default methods and itables, to clean out old methods. 3774 ResourceMark rm(_thread); 3775 if (ik->vtable_length() > 0) { 3776 ik->vtable().adjust_method_entries(&trace_name_printed); 3777 ik->adjust_default_methods(&trace_name_printed); 3778 } 3779 3780 if (ik->itable_length() > 0) { 3781 ik->itable().adjust_method_entries(&trace_name_printed); 3782 } 3783 3784 // The constant pools in other classes (other_cp) can refer to 3785 // old methods. We have to update method information in 3786 // other_cp's cache. If other_cp has a previous version, then we 3787 // have to repeat the process for each previous version. The 3788 // constant pool cache holds the Method*s for non-virtual 3789 // methods and for virtual, final methods. 3790 // 3791 // Special case: if the current class is being redefined by the current 3792 // VM_RedefineClasses operation, then new_cp has already been attached 3793 // to the_class and old_cp has already been added as a previous version. 3794 // The new_cp doesn't have any cached references to old methods so it 3795 // doesn't need to be updated and we could optimize by skipping it. 3796 // However, the current class can be marked as being redefined by another 3797 // VM_RedefineClasses operation which has already executed its doit_prologue 3798 // and needs cpcache method entries adjusted. For simplicity, the cpcache 3799 // update is done unconditionally. It should result in doing nothing for 3800 // classes being redefined by the current VM_RedefineClasses operation. 3801 // Method entries in the previous version(s) are adjusted as well. 3802 ConstantPoolCache* cp_cache; 3803 3804 // this klass' constant pool cache may need adjustment 3805 ConstantPool* other_cp = ik->constants(); 3806 cp_cache = other_cp->cache(); 3807 if (cp_cache != NULL) { 3808 cp_cache->adjust_method_entries(&trace_name_printed); 3809 } 3810 3811 // the previous versions' constant pool caches may need adjustment 3812 for (InstanceKlass* pv_node = ik->previous_versions(); 3813 pv_node != NULL; 3814 pv_node = pv_node->previous_versions()) { 3815 cp_cache = pv_node->constants()->cache(); 3816 if (cp_cache != NULL) { 3817 cp_cache->adjust_method_entries(&trace_name_printed); 3818 } 3819 } 3820 } 3821 } 3822 3823 void VM_RedefineClasses::update_jmethod_ids() { 3824 for (int j = 0; j < _matching_methods_length; ++j) { 3825 Method* old_method = _matching_old_methods[j]; 3826 jmethodID jmid = old_method->find_jmethod_id_or_null(); 3827 if (jmid != NULL) { 3828 // There is a jmethodID, change it to point to the new method 3829 Method* new_method = _matching_new_methods[j]; 3830 Method::change_method_associated_with_jmethod_id(jmid, new_method); 3831 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j], 3832 "should be replaced"); 3833 } 3834 } 3835 } 3836 3837 int VM_RedefineClasses::check_methods_and_mark_as_obsolete() { 3838 int emcp_method_count = 0; 3839 int obsolete_count = 0; 3840 int old_index = 0; 3841 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) { 3842 Method* old_method = _matching_old_methods[j]; 3843 Method* new_method = _matching_new_methods[j]; 3844 Method* old_array_method; 3845 3846 // Maintain an old_index into the _old_methods array by skipping 3847 // deleted methods 3848 while ((old_array_method = _old_methods->at(old_index)) != old_method) { 3849 ++old_index; 3850 } 3851 3852 if (MethodComparator::methods_EMCP(old_method, new_method)) { 3853 // The EMCP definition from JSR-163 requires the bytecodes to be 3854 // the same with the exception of constant pool indices which may 3855 // differ. However, the constants referred to by those indices 3856 // must be the same. 3857 // 3858 // We use methods_EMCP() for comparison since constant pool 3859 // merging can remove duplicate constant pool entries that were 3860 // present in the old method and removed from the rewritten new 3861 // method. A faster binary comparison function would consider the 3862 // old and new methods to be different when they are actually 3863 // EMCP. 3864 // 3865 // The old and new methods are EMCP and you would think that we 3866 // could get rid of one of them here and now and save some space. 3867 // However, the concept of EMCP only considers the bytecodes and 3868 // the constant pool entries in the comparison. Other things, 3869 // e.g., the line number table (LNT) or the local variable table 3870 // (LVT) don't count in the comparison. So the new (and EMCP) 3871 // method can have a new LNT that we need so we can't just 3872 // overwrite the new method with the old method. 3873 // 3874 // When this routine is called, we have already attached the new 3875 // methods to the_class so the old methods are effectively 3876 // overwritten. However, if an old method is still executing, 3877 // then the old method cannot be collected until sometime after 3878 // the old method call has returned. So the overwriting of old 3879 // methods by new methods will save us space except for those 3880 // (hopefully few) old methods that are still executing. 3881 // 3882 // A method refers to a ConstMethod* and this presents another 3883 // possible avenue to space savings. The ConstMethod* in the 3884 // new method contains possibly new attributes (LNT, LVT, etc). 3885 // At first glance, it seems possible to save space by replacing 3886 // the ConstMethod* in the old method with the ConstMethod* 3887 // from the new method. The old and new methods would share the 3888 // same ConstMethod* and we would save the space occupied by 3889 // the old ConstMethod*. However, the ConstMethod* contains 3890 // a back reference to the containing method. Sharing the 3891 // ConstMethod* between two methods could lead to confusion in 3892 // the code that uses the back reference. This would lead to 3893 // brittle code that could be broken in non-obvious ways now or 3894 // in the future. 3895 // 3896 // Another possibility is to copy the ConstMethod* from the new 3897 // method to the old method and then overwrite the new method with 3898 // the old method. Since the ConstMethod* contains the bytecodes 3899 // for the method embedded in the oop, this option would change 3900 // the bytecodes out from under any threads executing the old 3901 // method and make the thread's bcp invalid. Since EMCP requires 3902 // that the bytecodes be the same modulo constant pool indices, it 3903 // is straight forward to compute the correct new bcp in the new 3904 // ConstMethod* from the old bcp in the old ConstMethod*. The 3905 // time consuming part would be searching all the frames in all 3906 // of the threads to find all of the calls to the old method. 3907 // 3908 // It looks like we will have to live with the limited savings 3909 // that we get from effectively overwriting the old methods 3910 // when the new methods are attached to the_class. 3911 3912 // Count number of methods that are EMCP. The method will be marked 3913 // old but not obsolete if it is EMCP. 3914 emcp_method_count++; 3915 3916 // An EMCP method is _not_ obsolete. An obsolete method has a 3917 // different jmethodID than the current method. An EMCP method 3918 // has the same jmethodID as the current method. Having the 3919 // same jmethodID for all EMCP versions of a method allows for 3920 // a consistent view of the EMCP methods regardless of which 3921 // EMCP method you happen to have in hand. For example, a 3922 // breakpoint set in one EMCP method will work for all EMCP 3923 // versions of the method including the current one. 3924 } else { 3925 // mark obsolete methods as such 3926 old_method->set_is_obsolete(); 3927 obsolete_count++; 3928 3929 // obsolete methods need a unique idnum so they become new entries in 3930 // the jmethodID cache in InstanceKlass 3931 assert(old_method->method_idnum() == new_method->method_idnum(), "must match"); 3932 u2 num = InstanceKlass::cast(_the_class)->next_method_idnum(); 3933 if (num != ConstMethod::UNSET_IDNUM) { 3934 old_method->set_method_idnum(num); 3935 } 3936 3937 // With tracing we try not to "yack" too much. The position of 3938 // this trace assumes there are fewer obsolete methods than 3939 // EMCP methods. 3940 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) { 3941 ResourceMark rm; 3942 log_trace(redefine, class, obsolete, mark) 3943 ("mark %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string()); 3944 } 3945 } 3946 old_method->set_is_old(); 3947 } 3948 for (int i = 0; i < _deleted_methods_length; ++i) { 3949 Method* old_method = _deleted_methods[i]; 3950 3951 assert(!old_method->has_vtable_index(), 3952 "cannot delete methods with vtable entries");; 3953 3954 // Mark all deleted methods as old, obsolete and deleted 3955 old_method->set_is_deleted(); 3956 old_method->set_is_old(); 3957 old_method->set_is_obsolete(); 3958 ++obsolete_count; 3959 // With tracing we try not to "yack" too much. The position of 3960 // this trace assumes there are fewer obsolete methods than 3961 // EMCP methods. 3962 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) { 3963 ResourceMark rm; 3964 log_trace(redefine, class, obsolete, mark) 3965 ("mark deleted %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string()); 3966 } 3967 } 3968 assert((emcp_method_count + obsolete_count) == _old_methods->length(), 3969 "sanity check"); 3970 log_trace(redefine, class, obsolete, mark)("EMCP_cnt=%d, obsolete_cnt=%d", emcp_method_count, obsolete_count); 3971 return emcp_method_count; 3972 } 3973 3974 // This internal class transfers the native function registration from old methods 3975 // to new methods. It is designed to handle both the simple case of unchanged 3976 // native methods and the complex cases of native method prefixes being added and/or 3977 // removed. 3978 // It expects only to be used during the VM_RedefineClasses op (a safepoint). 3979 // 3980 // This class is used after the new methods have been installed in "the_class". 3981 // 3982 // So, for example, the following must be handled. Where 'm' is a method and 3983 // a number followed by an underscore is a prefix. 3984 // 3985 // Old Name New Name 3986 // Simple transfer to new method m -> m 3987 // Add prefix m -> 1_m 3988 // Remove prefix 1_m -> m 3989 // Simultaneous add of prefixes m -> 3_2_1_m 3990 // Simultaneous removal of prefixes 3_2_1_m -> m 3991 // Simultaneous add and remove 1_m -> 2_m 3992 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m 3993 // 3994 class TransferNativeFunctionRegistration { 3995 private: 3996 InstanceKlass* the_class; 3997 int prefix_count; 3998 char** prefixes; 3999 4000 // Recursively search the binary tree of possibly prefixed method names. 4001 // Iteration could be used if all agents were well behaved. Full tree walk is 4002 // more resilent to agents not cleaning up intermediate methods. 4003 // Branch at each depth in the binary tree is: 4004 // (1) without the prefix. 4005 // (2) with the prefix. 4006 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...) 4007 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len, 4008 Symbol* signature) { 4009 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len); 4010 if (name_symbol != NULL) { 4011 Method* method = the_class->lookup_method(name_symbol, signature); 4012 if (method != NULL) { 4013 // Even if prefixed, intermediate methods must exist. 4014 if (method->is_native()) { 4015 // Wahoo, we found a (possibly prefixed) version of the method, return it. 4016 return method; 4017 } 4018 if (depth < prefix_count) { 4019 // Try applying further prefixes (other than this one). 4020 method = search_prefix_name_space(depth+1, name_str, name_len, signature); 4021 if (method != NULL) { 4022 return method; // found 4023 } 4024 4025 // Try adding this prefix to the method name and see if it matches 4026 // another method name. 4027 char* prefix = prefixes[depth]; 4028 size_t prefix_len = strlen(prefix); 4029 size_t trial_len = name_len + prefix_len; 4030 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1); 4031 strcpy(trial_name_str, prefix); 4032 strcat(trial_name_str, name_str); 4033 method = search_prefix_name_space(depth+1, trial_name_str, trial_len, 4034 signature); 4035 if (method != NULL) { 4036 // If found along this branch, it was prefixed, mark as such 4037 method->set_is_prefixed_native(); 4038 return method; // found 4039 } 4040 } 4041 } 4042 } 4043 return NULL; // This whole branch bore nothing 4044 } 4045 4046 // Return the method name with old prefixes stripped away. 4047 char* method_name_without_prefixes(Method* method) { 4048 Symbol* name = method->name(); 4049 char* name_str = name->as_utf8(); 4050 4051 // Old prefixing may be defunct, strip prefixes, if any. 4052 for (int i = prefix_count-1; i >= 0; i--) { 4053 char* prefix = prefixes[i]; 4054 size_t prefix_len = strlen(prefix); 4055 if (strncmp(prefix, name_str, prefix_len) == 0) { 4056 name_str += prefix_len; 4057 } 4058 } 4059 return name_str; 4060 } 4061 4062 // Strip any prefixes off the old native method, then try to find a 4063 // (possibly prefixed) new native that matches it. 4064 Method* strip_and_search_for_new_native(Method* method) { 4065 ResourceMark rm; 4066 char* name_str = method_name_without_prefixes(method); 4067 return search_prefix_name_space(0, name_str, strlen(name_str), 4068 method->signature()); 4069 } 4070 4071 public: 4072 4073 // Construct a native method transfer processor for this class. 4074 TransferNativeFunctionRegistration(InstanceKlass* _the_class) { 4075 assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); 4076 4077 the_class = _the_class; 4078 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count); 4079 } 4080 4081 // Attempt to transfer any of the old or deleted methods that are native 4082 void transfer_registrations(Method** old_methods, int methods_length) { 4083 for (int j = 0; j < methods_length; j++) { 4084 Method* old_method = old_methods[j]; 4085 4086 if (old_method->is_native() && old_method->has_native_function()) { 4087 Method* new_method = strip_and_search_for_new_native(old_method); 4088 if (new_method != NULL) { 4089 // Actually set the native function in the new method. 4090 // Redefine does not send events (except CFLH), certainly not this 4091 // behind the scenes re-registration. 4092 new_method->set_native_function(old_method->native_function(), 4093 !Method::native_bind_event_is_interesting); 4094 } 4095 } 4096 } 4097 } 4098 }; 4099 4100 // Don't lose the association between a native method and its JNI function. 4101 void VM_RedefineClasses::transfer_old_native_function_registrations(InstanceKlass* the_class) { 4102 TransferNativeFunctionRegistration transfer(the_class); 4103 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length); 4104 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length); 4105 } 4106 4107 // Deoptimize all compiled code that depends on the classes redefined. 4108 // 4109 // If the can_redefine_classes capability is obtained in the onload 4110 // phase then the compiler has recorded all dependencies from startup. 4111 // In that case we need only deoptimize and throw away all compiled code 4112 // that depends on the class. 4113 // 4114 // If can_redefine_classes is obtained sometime after the onload 4115 // phase then the dependency information may be incomplete. In that case 4116 // the first call to RedefineClasses causes all compiled code to be 4117 // thrown away. As can_redefine_classes has been obtained then 4118 // all future compilations will record dependencies so second and 4119 // subsequent calls to RedefineClasses need only throw away code 4120 // that depends on the class. 4121 // 4122 4123 void VM_RedefineClasses::flush_dependent_code() { 4124 assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); 4125 4126 bool deopt_needed; 4127 4128 // This is the first redefinition, mark all the nmethods for deoptimization 4129 if (!JvmtiExport::all_dependencies_are_recorded()) { 4130 log_debug(redefine, class, nmethod)("Marked all nmethods for deopt"); 4131 CodeCache::mark_all_nmethods_for_evol_deoptimization(); 4132 deopt_needed = true; 4133 } else { 4134 int deopt = CodeCache::mark_dependents_for_evol_deoptimization(); 4135 log_debug(redefine, class, nmethod)("Marked %d dependent nmethods for deopt", deopt); 4136 deopt_needed = (deopt != 0); 4137 } 4138 4139 if (deopt_needed) { 4140 CodeCache::flush_evol_dependents(); 4141 } 4142 4143 // From now on we know that the dependency information is complete 4144 JvmtiExport::set_all_dependencies_are_recorded(true); 4145 } 4146 4147 void VM_RedefineClasses::compute_added_deleted_matching_methods() { 4148 Method* old_method; 4149 Method* new_method; 4150 4151 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 4152 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 4153 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length()); 4154 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 4155 4156 _matching_methods_length = 0; 4157 _deleted_methods_length = 0; 4158 _added_methods_length = 0; 4159 4160 int nj = 0; 4161 int oj = 0; 4162 while (true) { 4163 if (oj >= _old_methods->length()) { 4164 if (nj >= _new_methods->length()) { 4165 break; // we've looked at everything, done 4166 } 4167 // New method at the end 4168 new_method = _new_methods->at(nj); 4169 _added_methods[_added_methods_length++] = new_method; 4170 ++nj; 4171 } else if (nj >= _new_methods->length()) { 4172 // Old method, at the end, is deleted 4173 old_method = _old_methods->at(oj); 4174 _deleted_methods[_deleted_methods_length++] = old_method; 4175 ++oj; 4176 } else { 4177 old_method = _old_methods->at(oj); 4178 new_method = _new_methods->at(nj); 4179 if (old_method->name() == new_method->name()) { 4180 if (old_method->signature() == new_method->signature()) { 4181 _matching_old_methods[_matching_methods_length ] = old_method; 4182 _matching_new_methods[_matching_methods_length++] = new_method; 4183 ++nj; 4184 ++oj; 4185 } else { 4186 // added overloaded have already been moved to the end, 4187 // so this is a deleted overloaded method 4188 _deleted_methods[_deleted_methods_length++] = old_method; 4189 ++oj; 4190 } 4191 } else { // names don't match 4192 if (old_method->name()->fast_compare(new_method->name()) > 0) { 4193 // new method 4194 _added_methods[_added_methods_length++] = new_method; 4195 ++nj; 4196 } else { 4197 // deleted method 4198 _deleted_methods[_deleted_methods_length++] = old_method; 4199 ++oj; 4200 } 4201 } 4202 } 4203 } 4204 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity"); 4205 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity"); 4206 } 4207 4208 4209 void VM_RedefineClasses::swap_annotations(InstanceKlass* the_class, 4210 InstanceKlass* scratch_class) { 4211 // Swap annotation fields values 4212 Annotations* old_annotations = the_class->annotations(); 4213 the_class->set_annotations(scratch_class->annotations()); 4214 scratch_class->set_annotations(old_annotations); 4215 } 4216 4217 4218 // Install the redefinition of a class: 4219 // - house keeping (flushing breakpoints and caches, deoptimizing 4220 // dependent compiled code) 4221 // - replacing parts in the_class with parts from scratch_class 4222 // - adding a weak reference to track the obsolete but interesting 4223 // parts of the_class 4224 // - adjusting constant pool caches and vtables in other classes 4225 // that refer to methods in the_class. These adjustments use the 4226 // ClassLoaderDataGraph::classes_do() facility which only allows 4227 // a helper method to be specified. The interesting parameters 4228 // that we would like to pass to the helper method are saved in 4229 // static global fields in the VM operation. 4230 void VM_RedefineClasses::redefine_single_class(Thread* current, jclass the_jclass, 4231 InstanceKlass* scratch_class) { 4232 4233 HandleMark hm(current); // make sure handles from this call are freed 4234 4235 if (log_is_enabled(Info, redefine, class, timer)) { 4236 _timer_rsc_phase1.start(); 4237 } 4238 4239 InstanceKlass* the_class = get_ik(the_jclass); 4240 4241 // Set a flag to control and optimize adjusting method entries 4242 _has_redefined_Object |= the_class == vmClasses::Object_klass(); 4243 4244 // Remove all breakpoints in methods of this class 4245 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints(); 4246 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class); 4247 4248 _old_methods = the_class->methods(); 4249 _new_methods = scratch_class->methods(); 4250 _the_class = the_class; 4251 compute_added_deleted_matching_methods(); 4252 update_jmethod_ids(); 4253 4254 _any_class_has_resolved_methods = the_class->has_resolved_methods() || _any_class_has_resolved_methods; 4255 4256 // Attach new constant pool to the original klass. The original 4257 // klass still refers to the old constant pool (for now). 4258 scratch_class->constants()->set_pool_holder(the_class); 4259 4260 #if 0 4261 // In theory, with constant pool merging in place we should be able 4262 // to save space by using the new, merged constant pool in place of 4263 // the old constant pool(s). By "pool(s)" I mean the constant pool in 4264 // the klass version we are replacing now and any constant pool(s) in 4265 // previous versions of klass. Nice theory, doesn't work in practice. 4266 // When this code is enabled, even simple programs throw NullPointer 4267 // exceptions. I'm guessing that this is caused by some constant pool 4268 // cache difference between the new, merged constant pool and the 4269 // constant pool that was just being used by the klass. I'm keeping 4270 // this code around to archive the idea, but the code has to remain 4271 // disabled for now. 4272 4273 // Attach each old method to the new constant pool. This can be 4274 // done here since we are past the bytecode verification and 4275 // constant pool optimization phases. 4276 for (int i = _old_methods->length() - 1; i >= 0; i--) { 4277 Method* method = _old_methods->at(i); 4278 method->set_constants(scratch_class->constants()); 4279 } 4280 4281 // NOTE: this doesn't work because you can redefine the same class in two 4282 // threads, each getting their own constant pool data appended to the 4283 // original constant pool. In order for the new methods to work when they 4284 // become old methods, they need to keep their updated copy of the constant pool. 4285 4286 { 4287 // walk all previous versions of the klass 4288 InstanceKlass *ik = the_class; 4289 PreviousVersionWalker pvw(ik); 4290 do { 4291 ik = pvw.next_previous_version(); 4292 if (ik != NULL) { 4293 4294 // attach previous version of klass to the new constant pool 4295 ik->set_constants(scratch_class->constants()); 4296 4297 // Attach each method in the previous version of klass to the 4298 // new constant pool 4299 Array<Method*>* prev_methods = ik->methods(); 4300 for (int i = prev_methods->length() - 1; i >= 0; i--) { 4301 Method* method = prev_methods->at(i); 4302 method->set_constants(scratch_class->constants()); 4303 } 4304 } 4305 } while (ik != NULL); 4306 } 4307 #endif 4308 4309 // Replace methods and constantpool 4310 the_class->set_methods(_new_methods); 4311 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods, 4312 // and to be able to undo operation easily. 4313 4314 Array<int>* old_ordering = the_class->method_ordering(); 4315 the_class->set_method_ordering(scratch_class->method_ordering()); 4316 scratch_class->set_method_ordering(old_ordering); 4317 4318 ConstantPool* old_constants = the_class->constants(); 4319 the_class->set_constants(scratch_class->constants()); 4320 scratch_class->set_constants(old_constants); // See the previous comment. 4321 #if 0 4322 // We are swapping the guts of "the new class" with the guts of "the 4323 // class". Since the old constant pool has just been attached to "the 4324 // new class", it seems logical to set the pool holder in the old 4325 // constant pool also. However, doing this will change the observable 4326 // class hierarchy for any old methods that are still executing. A 4327 // method can query the identity of its "holder" and this query uses 4328 // the method's constant pool link to find the holder. The change in 4329 // holding class from "the class" to "the new class" can confuse 4330 // things. 4331 // 4332 // Setting the old constant pool's holder will also cause 4333 // verification done during vtable initialization below to fail. 4334 // During vtable initialization, the vtable's class is verified to be 4335 // a subtype of the method's holder. The vtable's class is "the 4336 // class" and the method's holder is gotten from the constant pool 4337 // link in the method itself. For "the class"'s directly implemented 4338 // methods, the method holder is "the class" itself (as gotten from 4339 // the new constant pool). The check works fine in this case. The 4340 // check also works fine for methods inherited from super classes. 4341 // 4342 // Miranda methods are a little more complicated. A miranda method is 4343 // provided by an interface when the class implementing the interface 4344 // does not provide its own method. These interfaces are implemented 4345 // internally as an InstanceKlass. These special instanceKlasses 4346 // share the constant pool of the class that "implements" the 4347 // interface. By sharing the constant pool, the method holder of a 4348 // miranda method is the class that "implements" the interface. In a 4349 // non-redefine situation, the subtype check works fine. However, if 4350 // the old constant pool's pool holder is modified, then the check 4351 // fails because there is no class hierarchy relationship between the 4352 // vtable's class and "the new class". 4353 4354 old_constants->set_pool_holder(scratch_class()); 4355 #endif 4356 4357 // track number of methods that are EMCP for add_previous_version() call below 4358 int emcp_method_count = check_methods_and_mark_as_obsolete(); 4359 transfer_old_native_function_registrations(the_class); 4360 4361 // The class file bytes from before any retransformable agents mucked 4362 // with them was cached on the scratch class, move to the_class. 4363 // Note: we still want to do this if nothing needed caching since it 4364 // should get cleared in the_class too. 4365 if (the_class->get_cached_class_file() == 0) { 4366 // the_class doesn't have a cache yet so copy it 4367 the_class->set_cached_class_file(scratch_class->get_cached_class_file()); 4368 } 4369 else if (scratch_class->get_cached_class_file() != 4370 the_class->get_cached_class_file()) { 4371 // The same class can be present twice in the scratch classes list or there 4372 // are multiple concurrent RetransformClasses calls on different threads. 4373 // In such cases we have to deallocate scratch_class cached_class_file. 4374 os::free(scratch_class->get_cached_class_file()); 4375 } 4376 4377 // NULL out in scratch class to not delete twice. The class to be redefined 4378 // always owns these bytes. 4379 scratch_class->set_cached_class_file(NULL); 4380 4381 // Replace inner_classes 4382 Array<u2>* old_inner_classes = the_class->inner_classes(); 4383 the_class->set_inner_classes(scratch_class->inner_classes()); 4384 scratch_class->set_inner_classes(old_inner_classes); 4385 4386 // Initialize the vtable and interface table after 4387 // methods have been rewritten 4388 // no exception should happen here since we explicitly 4389 // do not check loader constraints. 4390 // compare_and_normalize_class_versions has already checked: 4391 // - classloaders unchanged, signatures unchanged 4392 // - all instanceKlasses for redefined classes reused & contents updated 4393 the_class->vtable().initialize_vtable(); 4394 the_class->itable().initialize_itable(); 4395 4396 // Leave arrays of jmethodIDs and itable index cache unchanged 4397 4398 // Copy the "source file name" attribute from new class version 4399 the_class->set_source_file_name_index( 4400 scratch_class->source_file_name_index()); 4401 4402 // Copy the "source debug extension" attribute from new class version 4403 the_class->set_source_debug_extension( 4404 scratch_class->source_debug_extension(), 4405 scratch_class->source_debug_extension() == NULL ? 0 : 4406 (int)strlen(scratch_class->source_debug_extension())); 4407 4408 // Use of javac -g could be different in the old and the new 4409 if (scratch_class->access_flags().has_localvariable_table() != 4410 the_class->access_flags().has_localvariable_table()) { 4411 4412 AccessFlags flags = the_class->access_flags(); 4413 if (scratch_class->access_flags().has_localvariable_table()) { 4414 flags.set_has_localvariable_table(); 4415 } else { 4416 flags.clear_has_localvariable_table(); 4417 } 4418 the_class->set_access_flags(flags); 4419 } 4420 4421 swap_annotations(the_class, scratch_class); 4422 4423 // Replace minor version number of class file 4424 u2 old_minor_version = the_class->constants()->minor_version(); 4425 the_class->constants()->set_minor_version(scratch_class->constants()->minor_version()); 4426 scratch_class->constants()->set_minor_version(old_minor_version); 4427 4428 // Replace major version number of class file 4429 u2 old_major_version = the_class->constants()->major_version(); 4430 the_class->constants()->set_major_version(scratch_class->constants()->major_version()); 4431 scratch_class->constants()->set_major_version(old_major_version); 4432 4433 // Replace CP indexes for class and name+type of enclosing method 4434 u2 old_class_idx = the_class->enclosing_method_class_index(); 4435 u2 old_method_idx = the_class->enclosing_method_method_index(); 4436 the_class->set_enclosing_method_indices( 4437 scratch_class->enclosing_method_class_index(), 4438 scratch_class->enclosing_method_method_index()); 4439 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx); 4440 4441 the_class->set_has_been_redefined(); 4442 4443 // Scratch class is unloaded but still needs cleaning, and skipping for CDS. 4444 scratch_class->set_is_scratch_class(); 4445 4446 // keep track of previous versions of this class 4447 the_class->add_previous_version(scratch_class, emcp_method_count); 4448 4449 _timer_rsc_phase1.stop(); 4450 if (log_is_enabled(Info, redefine, class, timer)) { 4451 _timer_rsc_phase2.start(); 4452 } 4453 4454 if (the_class->oop_map_cache() != NULL) { 4455 // Flush references to any obsolete methods from the oop map cache 4456 // so that obsolete methods are not pinned. 4457 the_class->oop_map_cache()->flush_obsolete_entries(); 4458 } 4459 4460 increment_class_counter(the_class); 4461 4462 if (EventClassRedefinition::is_enabled()) { 4463 EventClassRedefinition event; 4464 event.set_classModificationCount(java_lang_Class::classRedefinedCount(the_class->java_mirror())); 4465 event.set_redefinedClass(the_class); 4466 event.set_redefinitionId(_id); 4467 event.commit(); 4468 } 4469 4470 { 4471 ResourceMark rm(current); 4472 // increment the classRedefinedCount field in the_class and in any 4473 // direct and indirect subclasses of the_class 4474 log_info(redefine, class, load) 4475 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)", 4476 the_class->external_name(), java_lang_Class::classRedefinedCount(the_class->java_mirror()), os::available_memory() >> 10); 4477 Events::log_redefinition(current, "redefined class name=%s, count=%d", 4478 the_class->external_name(), 4479 java_lang_Class::classRedefinedCount(the_class->java_mirror())); 4480 4481 } 4482 _timer_rsc_phase2.stop(); 4483 4484 } // end redefine_single_class() 4485 4486 4487 // Increment the classRedefinedCount field in the specific InstanceKlass 4488 // and in all direct and indirect subclasses. 4489 void VM_RedefineClasses::increment_class_counter(InstanceKlass* ik) { 4490 for (ClassHierarchyIterator iter(ik); !iter.done(); iter.next()) { 4491 // Only update instanceKlasses 4492 Klass* sub = iter.klass(); 4493 if (sub->is_instance_klass()) { 4494 oop class_mirror = InstanceKlass::cast(sub)->java_mirror(); 4495 Klass* class_oop = java_lang_Class::as_Klass(class_mirror); 4496 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1; 4497 java_lang_Class::set_classRedefinedCount(class_mirror, new_count); 4498 4499 if (class_oop != _the_class) { 4500 // _the_class count is printed at end of redefine_single_class() 4501 log_debug(redefine, class, subclass)("updated count in subclass=%s to %d", ik->external_name(), new_count); 4502 } 4503 } 4504 } 4505 } 4506 4507 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) { 4508 bool no_old_methods = true; // be optimistic 4509 4510 // Both array and instance classes have vtables. 4511 // a vtable should never contain old or obsolete methods 4512 ResourceMark rm(_thread); 4513 if (k->vtable_length() > 0 && 4514 !k->vtable().check_no_old_or_obsolete_entries()) { 4515 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 4516 log_trace(redefine, class, obsolete, metadata) 4517 ("klassVtable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s", 4518 k->signature_name()); 4519 k->vtable().dump_vtable(); 4520 } 4521 no_old_methods = false; 4522 } 4523 4524 if (k->is_instance_klass()) { 4525 HandleMark hm(_thread); 4526 InstanceKlass *ik = InstanceKlass::cast(k); 4527 4528 // an itable should never contain old or obsolete methods 4529 if (ik->itable_length() > 0 && 4530 !ik->itable().check_no_old_or_obsolete_entries()) { 4531 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 4532 log_trace(redefine, class, obsolete, metadata) 4533 ("klassItable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s", 4534 ik->signature_name()); 4535 ik->itable().dump_itable(); 4536 } 4537 no_old_methods = false; 4538 } 4539 4540 // the constant pool cache should never contain non-deleted old or obsolete methods 4541 if (ik->constants() != NULL && 4542 ik->constants()->cache() != NULL && 4543 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) { 4544 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 4545 log_trace(redefine, class, obsolete, metadata) 4546 ("cp-cache::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s", 4547 ik->signature_name()); 4548 ik->constants()->cache()->dump_cache(); 4549 } 4550 no_old_methods = false; 4551 } 4552 } 4553 4554 // print and fail guarantee if old methods are found. 4555 if (!no_old_methods) { 4556 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 4557 dump_methods(); 4558 } else { 4559 log_trace(redefine, class)("Use the '-Xlog:redefine+class*:' option " 4560 "to see more info about the following guarantee() failure."); 4561 } 4562 guarantee(false, "OLD and/or OBSOLETE method(s) found"); 4563 } 4564 } 4565 4566 u8 VM_RedefineClasses::next_id() { 4567 while (true) { 4568 u8 id = _id_counter; 4569 u8 next_id = id + 1; 4570 u8 result = Atomic::cmpxchg(&_id_counter, id, next_id); 4571 if (result == id) { 4572 return next_id; 4573 } 4574 } 4575 } 4576 4577 void VM_RedefineClasses::dump_methods() { 4578 int j; 4579 log_trace(redefine, class, dump)("_old_methods --"); 4580 for (j = 0; j < _old_methods->length(); ++j) { 4581 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4582 Method* m = _old_methods->at(j); 4583 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4584 m->access_flags().print_on(&log_stream); 4585 log_stream.print(" -- "); 4586 m->print_name(&log_stream); 4587 log_stream.cr(); 4588 } 4589 log_trace(redefine, class, dump)("_new_methods --"); 4590 for (j = 0; j < _new_methods->length(); ++j) { 4591 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4592 Method* m = _new_methods->at(j); 4593 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4594 m->access_flags().print_on(&log_stream); 4595 log_stream.print(" -- "); 4596 m->print_name(&log_stream); 4597 log_stream.cr(); 4598 } 4599 log_trace(redefine, class, dump)("_matching_methods --"); 4600 for (j = 0; j < _matching_methods_length; ++j) { 4601 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4602 Method* m = _matching_old_methods[j]; 4603 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4604 m->access_flags().print_on(&log_stream); 4605 log_stream.print(" -- "); 4606 m->print_name(); 4607 log_stream.cr(); 4608 4609 m = _matching_new_methods[j]; 4610 log_stream.print(" (%5d) ", m->vtable_index()); 4611 m->access_flags().print_on(&log_stream); 4612 log_stream.cr(); 4613 } 4614 log_trace(redefine, class, dump)("_deleted_methods --"); 4615 for (j = 0; j < _deleted_methods_length; ++j) { 4616 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4617 Method* m = _deleted_methods[j]; 4618 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4619 m->access_flags().print_on(&log_stream); 4620 log_stream.print(" -- "); 4621 m->print_name(&log_stream); 4622 log_stream.cr(); 4623 } 4624 log_trace(redefine, class, dump)("_added_methods --"); 4625 for (j = 0; j < _added_methods_length; ++j) { 4626 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4627 Method* m = _added_methods[j]; 4628 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4629 m->access_flags().print_on(&log_stream); 4630 log_stream.print(" -- "); 4631 m->print_name(&log_stream); 4632 log_stream.cr(); 4633 } 4634 } 4635 4636 void VM_RedefineClasses::print_on_error(outputStream* st) const { 4637 VM_Operation::print_on_error(st); 4638 if (_the_class != NULL) { 4639 ResourceMark rm; 4640 st->print_cr(", redefining class %s", _the_class->external_name()); 4641 } 4642 }