1 /* 2 * Copyright (c) 2003, 2018, 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 "aot/aotLoader.hpp" 27 #include "classfile/classFileStream.hpp" 28 #include "classfile/metadataOnStackMark.hpp" 29 #include "classfile/systemDictionary.hpp" 30 #include "classfile/verifier.hpp" 31 #include "code/codeCache.hpp" 32 #include "compiler/compileBroker.hpp" 33 #include "interpreter/oopMapCache.hpp" 34 #include "interpreter/rewriter.hpp" 35 #include "logging/logStream.hpp" 36 #include "memory/metadataFactory.hpp" 37 #include "memory/metaspaceShared.hpp" 38 #include "memory/resourceArea.hpp" 39 #include "memory/universe.hpp" 40 #include "oops/fieldStreams.hpp" 41 #include "oops/klassVtable.hpp" 42 #include "oops/oop.inline.hpp" 43 #include "prims/jvmtiImpl.hpp" 44 #include "prims/jvmtiRedefineClasses.hpp" 45 #include "prims/jvmtiThreadState.inline.hpp" 46 #include "prims/resolvedMethodTable.hpp" 47 #include "prims/methodComparator.hpp" 48 #include "runtime/deoptimization.hpp" 49 #include "runtime/handles.inline.hpp" 50 #include "runtime/jniHandles.inline.hpp" 51 #include "runtime/relocator.hpp" 52 #include "runtime/safepointVerifiers.hpp" 53 #include "utilities/bitMap.inline.hpp" 54 #include "utilities/events.hpp" 55 56 Array<Method*>* VM_RedefineClasses::_old_methods = NULL; 57 Array<Method*>* VM_RedefineClasses::_new_methods = NULL; 58 Method** VM_RedefineClasses::_matching_old_methods = NULL; 59 Method** VM_RedefineClasses::_matching_new_methods = NULL; 60 Method** VM_RedefineClasses::_deleted_methods = NULL; 61 Method** VM_RedefineClasses::_added_methods = NULL; 62 int VM_RedefineClasses::_matching_methods_length = 0; 63 int VM_RedefineClasses::_deleted_methods_length = 0; 64 int VM_RedefineClasses::_added_methods_length = 0; 65 Klass* VM_RedefineClasses::_the_class = NULL; 66 67 68 VM_RedefineClasses::VM_RedefineClasses(jint class_count, 69 const jvmtiClassDefinition *class_defs, 70 JvmtiClassLoadKind class_load_kind) { 71 _class_count = class_count; 72 _class_defs = class_defs; 73 _class_load_kind = class_load_kind; 74 _any_class_has_resolved_methods = false; 75 _res = JVMTI_ERROR_NONE; 76 } 77 78 static inline InstanceKlass* get_ik(jclass def) { 79 oop mirror = JNIHandles::resolve_non_null(def); 80 return InstanceKlass::cast(java_lang_Class::as_Klass(mirror)); 81 } 82 83 // If any of the classes are being redefined, wait 84 // Parallel constant pool merging leads to indeterminate constant pools. 85 void VM_RedefineClasses::lock_classes() { 86 MutexLocker ml(RedefineClasses_lock); 87 bool has_redefined; 88 do { 89 has_redefined = false; 90 // Go through classes each time until none are being redefined. 91 for (int i = 0; i < _class_count; i++) { 92 if (get_ik(_class_defs[i].klass)->is_being_redefined()) { 93 RedefineClasses_lock->wait(); 94 has_redefined = true; 95 break; // for loop 96 } 97 } 98 } while (has_redefined); 99 for (int i = 0; i < _class_count; i++) { 100 get_ik(_class_defs[i].klass)->set_is_being_redefined(true); 101 } 102 RedefineClasses_lock->notify_all(); 103 } 104 105 void VM_RedefineClasses::unlock_classes() { 106 MutexLocker ml(RedefineClasses_lock); 107 for (int i = 0; i < _class_count; i++) { 108 assert(get_ik(_class_defs[i].klass)->is_being_redefined(), 109 "should be being redefined to get here"); 110 get_ik(_class_defs[i].klass)->set_is_being_redefined(false); 111 } 112 RedefineClasses_lock->notify_all(); 113 } 114 115 bool VM_RedefineClasses::doit_prologue() { 116 if (_class_count == 0) { 117 _res = JVMTI_ERROR_NONE; 118 return false; 119 } 120 if (_class_defs == NULL) { 121 _res = JVMTI_ERROR_NULL_POINTER; 122 return false; 123 } 124 for (int i = 0; i < _class_count; i++) { 125 if (_class_defs[i].klass == NULL) { 126 _res = JVMTI_ERROR_INVALID_CLASS; 127 return false; 128 } 129 if (_class_defs[i].class_byte_count == 0) { 130 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT; 131 return false; 132 } 133 if (_class_defs[i].class_bytes == NULL) { 134 _res = JVMTI_ERROR_NULL_POINTER; 135 return false; 136 } 137 138 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass); 139 // classes for primitives and arrays and vm anonymous classes cannot be redefined 140 // check here so following code can assume these classes are InstanceKlass 141 if (!is_modifiable_class(mirror)) { 142 _res = JVMTI_ERROR_UNMODIFIABLE_CLASS; 143 return false; 144 } 145 } 146 147 // Start timer after all the sanity checks; not quite accurate, but 148 // better than adding a bunch of stop() calls. 149 if (log_is_enabled(Info, redefine, class, timer)) { 150 _timer_vm_op_prologue.start(); 151 } 152 153 lock_classes(); 154 // We first load new class versions in the prologue, because somewhere down the 155 // call chain it is required that the current thread is a Java thread. 156 _res = load_new_class_versions(Thread::current()); 157 if (_res != JVMTI_ERROR_NONE) { 158 // free any successfully created classes, since none are redefined 159 for (int i = 0; i < _class_count; i++) { 160 if (_scratch_classes[i] != NULL) { 161 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data(); 162 // Free the memory for this class at class unloading time. Not before 163 // because CMS might think this is still live. 164 InstanceKlass* ik = get_ik(_class_defs[i].klass); 165 if (ik->get_cached_class_file() == _scratch_classes[i]->get_cached_class_file()) { 166 // Don't double-free cached_class_file copied from the original class if error. 167 _scratch_classes[i]->set_cached_class_file(NULL); 168 } 169 cld->add_to_deallocate_list(InstanceKlass::cast(_scratch_classes[i])); 170 } 171 } 172 // Free os::malloc allocated memory in load_new_class_version. 173 os::free(_scratch_classes); 174 _timer_vm_op_prologue.stop(); 175 unlock_classes(); 176 return false; 177 } 178 179 _timer_vm_op_prologue.stop(); 180 return true; 181 } 182 183 void VM_RedefineClasses::doit() { 184 Thread *thread = Thread::current(); 185 186 #if INCLUDE_CDS 187 if (UseSharedSpaces) { 188 // Sharing is enabled so we remap the shared readonly space to 189 // shared readwrite, private just in case we need to redefine 190 // a shared class. We do the remap during the doit() phase of 191 // the safepoint to be safer. 192 if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) { 193 log_info(redefine, class, load)("failed to remap shared readonly space to readwrite, private"); 194 _res = JVMTI_ERROR_INTERNAL; 195 return; 196 } 197 } 198 #endif 199 200 // Mark methods seen on stack and everywhere else so old methods are not 201 // cleaned up if they're on the stack. 202 MetadataOnStackMark md_on_stack(true); 203 HandleMark hm(thread); // make sure any handles created are deleted 204 // before the stack walk again. 205 206 for (int i = 0; i < _class_count; i++) { 207 redefine_single_class(_class_defs[i].klass, _scratch_classes[i], thread); 208 } 209 210 // Clean out MethodData pointing to old Method* 211 // Have to do this after all classes are redefined and all methods that 212 // are redefined are marked as old. 213 MethodDataCleaner clean_weak_method_links; 214 ClassLoaderDataGraph::classes_do(&clean_weak_method_links); 215 216 // JSR-292 support 217 if (_any_class_has_resolved_methods) { 218 bool trace_name_printed = false; 219 ResolvedMethodTable::adjust_method_entries(&trace_name_printed); 220 } 221 222 // Disable any dependent concurrent compilations 223 SystemDictionary::notice_modification(); 224 225 // Set flag indicating that some invariants are no longer true. 226 // See jvmtiExport.hpp for detailed explanation. 227 JvmtiExport::set_has_redefined_a_class(); 228 229 // check_class() is optionally called for product bits, but is 230 // always called for non-product bits. 231 #ifdef PRODUCT 232 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 233 #endif 234 log_trace(redefine, class, obsolete, metadata)("calling check_class"); 235 CheckClass check_class(thread); 236 ClassLoaderDataGraph::classes_do(&check_class); 237 #ifdef PRODUCT 238 } 239 #endif 240 } 241 242 void VM_RedefineClasses::doit_epilogue() { 243 unlock_classes(); 244 245 // Free os::malloc allocated memory. 246 os::free(_scratch_classes); 247 248 // Reset the_class to null for error printing. 249 _the_class = NULL; 250 251 if (log_is_enabled(Info, redefine, class, timer)) { 252 // Used to have separate timers for "doit" and "all", but the timer 253 // overhead skewed the measurements. 254 julong doit_time = _timer_rsc_phase1.milliseconds() + 255 _timer_rsc_phase2.milliseconds(); 256 julong all_time = _timer_vm_op_prologue.milliseconds() + doit_time; 257 258 log_info(redefine, class, timer) 259 ("vm_op: all=" JULONG_FORMAT " prologue=" JULONG_FORMAT " doit=" JULONG_FORMAT, 260 all_time, (julong)_timer_vm_op_prologue.milliseconds(), doit_time); 261 log_info(redefine, class, timer) 262 ("redefine_single_class: phase1=" JULONG_FORMAT " phase2=" JULONG_FORMAT, 263 (julong)_timer_rsc_phase1.milliseconds(), (julong)_timer_rsc_phase2.milliseconds()); 264 } 265 } 266 267 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) { 268 // classes for primitives cannot be redefined 269 if (java_lang_Class::is_primitive(klass_mirror)) { 270 return false; 271 } 272 Klass* k = java_lang_Class::as_Klass(klass_mirror); 273 // classes for arrays cannot be redefined 274 if (k == NULL || !k->is_instance_klass()) { 275 return false; 276 } 277 278 // Cannot redefine or retransform an anonymous class. 279 if (InstanceKlass::cast(k)->is_anonymous()) { 280 return false; 281 } 282 return true; 283 } 284 285 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p 286 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For 287 // direct CP entries, there is just the current entry to append. For 288 // indirect and double-indirect CP entries, there are zero or more 289 // referenced CP entries along with the current entry to append. 290 // Indirect and double-indirect CP entries are handled by recursive 291 // calls to append_entry() as needed. The referenced CP entries are 292 // always appended to *merge_cp_p before the referee CP entry. These 293 // referenced CP entries may already exist in *merge_cp_p in which case 294 // there is nothing extra to append and only the current entry is 295 // appended. 296 void VM_RedefineClasses::append_entry(const constantPoolHandle& scratch_cp, 297 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, 298 TRAPS) { 299 300 // append is different depending on entry tag type 301 switch (scratch_cp->tag_at(scratch_i).value()) { 302 303 // The old verifier is implemented outside the VM. It loads classes, 304 // but does not resolve constant pool entries directly so we never 305 // see Class entries here with the old verifier. Similarly the old 306 // verifier does not like Class entries in the input constant pool. 307 // The split-verifier is implemented in the VM so it can optionally 308 // and directly resolve constant pool entries to load classes. The 309 // split-verifier can accept either Class entries or UnresolvedClass 310 // entries in the input constant pool. We revert the appended copy 311 // back to UnresolvedClass so that either verifier will be happy 312 // with the constant pool entry. 313 // 314 // this is an indirect CP entry so it needs special handling 315 case JVM_CONSTANT_Class: 316 case JVM_CONSTANT_UnresolvedClass: 317 { 318 int name_i = scratch_cp->klass_name_index_at(scratch_i); 319 int new_name_i = find_or_append_indirect_entry(scratch_cp, name_i, merge_cp_p, 320 merge_cp_length_p, THREAD); 321 322 if (new_name_i != name_i) { 323 log_trace(redefine, class, constantpool) 324 ("Class entry@%d name_index change: %d to %d", 325 *merge_cp_length_p, name_i, new_name_i); 326 } 327 328 (*merge_cp_p)->temp_unresolved_klass_at_put(*merge_cp_length_p, new_name_i); 329 if (scratch_i != *merge_cp_length_p) { 330 // The new entry in *merge_cp_p is at a different index than 331 // the new entry in scratch_cp so we need to map the index values. 332 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 333 } 334 (*merge_cp_length_p)++; 335 } break; 336 337 // these are direct CP entries so they can be directly appended, 338 // but double and long take two constant pool entries 339 case JVM_CONSTANT_Double: // fall through 340 case JVM_CONSTANT_Long: 341 { 342 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p, 343 THREAD); 344 345 if (scratch_i != *merge_cp_length_p) { 346 // The new entry in *merge_cp_p is at a different index than 347 // the new entry in scratch_cp so we need to map the index values. 348 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 349 } 350 (*merge_cp_length_p) += 2; 351 } break; 352 353 // these are direct CP entries so they can be directly appended 354 case JVM_CONSTANT_Float: // fall through 355 case JVM_CONSTANT_Integer: // fall through 356 case JVM_CONSTANT_Utf8: // fall through 357 358 // This was an indirect CP entry, but it has been changed into 359 // Symbol*s so this entry can be directly appended. 360 case JVM_CONSTANT_String: // fall through 361 { 362 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p, 363 THREAD); 364 365 if (scratch_i != *merge_cp_length_p) { 366 // The new entry in *merge_cp_p is at a different index than 367 // the new entry in scratch_cp so we need to map the index values. 368 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 369 } 370 (*merge_cp_length_p)++; 371 } break; 372 373 // this is an indirect CP entry so it needs special handling 374 case JVM_CONSTANT_NameAndType: 375 { 376 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i); 377 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p, 378 merge_cp_length_p, THREAD); 379 380 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i); 381 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i, 382 merge_cp_p, merge_cp_length_p, 383 THREAD); 384 385 // If the referenced entries already exist in *merge_cp_p, then 386 // both new_name_ref_i and new_signature_ref_i will both be 0. 387 // In that case, all we are appending is the current entry. 388 if (new_name_ref_i != name_ref_i) { 389 log_trace(redefine, class, constantpool) 390 ("NameAndType entry@%d name_ref_index change: %d to %d", 391 *merge_cp_length_p, name_ref_i, new_name_ref_i); 392 } 393 if (new_signature_ref_i != signature_ref_i) { 394 log_trace(redefine, class, constantpool) 395 ("NameAndType entry@%d signature_ref_index change: %d to %d", 396 *merge_cp_length_p, signature_ref_i, new_signature_ref_i); 397 } 398 399 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p, 400 new_name_ref_i, new_signature_ref_i); 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)++; 407 } break; 408 409 // this is a double-indirect CP entry so it needs special handling 410 case JVM_CONSTANT_Fieldref: // fall through 411 case JVM_CONSTANT_InterfaceMethodref: // fall through 412 case JVM_CONSTANT_Methodref: 413 { 414 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i); 415 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i, 416 merge_cp_p, merge_cp_length_p, THREAD); 417 418 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i); 419 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i, 420 merge_cp_p, merge_cp_length_p, THREAD); 421 422 const char *entry_name = NULL; 423 switch (scratch_cp->tag_at(scratch_i).value()) { 424 case JVM_CONSTANT_Fieldref: 425 entry_name = "Fieldref"; 426 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i, 427 new_name_and_type_ref_i); 428 break; 429 case JVM_CONSTANT_InterfaceMethodref: 430 entry_name = "IFMethodref"; 431 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p, 432 new_klass_ref_i, new_name_and_type_ref_i); 433 break; 434 case JVM_CONSTANT_Methodref: 435 entry_name = "Methodref"; 436 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i, 437 new_name_and_type_ref_i); 438 break; 439 default: 440 guarantee(false, "bad switch"); 441 break; 442 } 443 444 if (klass_ref_i != new_klass_ref_i) { 445 log_trace(redefine, class, constantpool) 446 ("%s entry@%d class_index changed: %d to %d", entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i); 447 } 448 if (name_and_type_ref_i != new_name_and_type_ref_i) { 449 log_trace(redefine, class, constantpool) 450 ("%s entry@%d name_and_type_index changed: %d to %d", 451 entry_name, *merge_cp_length_p, name_and_type_ref_i, new_name_and_type_ref_i); 452 } 453 454 if (scratch_i != *merge_cp_length_p) { 455 // The new entry in *merge_cp_p is at a different index than 456 // the new entry in scratch_cp so we need to map the index values. 457 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 458 } 459 (*merge_cp_length_p)++; 460 } break; 461 462 // this is an indirect CP entry so it needs special handling 463 case JVM_CONSTANT_MethodType: 464 { 465 int ref_i = scratch_cp->method_type_index_at(scratch_i); 466 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p, 467 merge_cp_length_p, THREAD); 468 if (new_ref_i != ref_i) { 469 log_trace(redefine, class, constantpool) 470 ("MethodType entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i); 471 } 472 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i); 473 if (scratch_i != *merge_cp_length_p) { 474 // The new entry in *merge_cp_p is at a different index than 475 // the new entry in scratch_cp so we need to map the index values. 476 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 477 } 478 (*merge_cp_length_p)++; 479 } break; 480 481 // this is an indirect CP entry so it needs special handling 482 case JVM_CONSTANT_MethodHandle: 483 { 484 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i); 485 int ref_i = scratch_cp->method_handle_index_at(scratch_i); 486 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p, 487 merge_cp_length_p, THREAD); 488 if (new_ref_i != ref_i) { 489 log_trace(redefine, class, constantpool) 490 ("MethodHandle entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i); 491 } 492 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i); 493 if (scratch_i != *merge_cp_length_p) { 494 // The new entry in *merge_cp_p is at a different index than 495 // the new entry in scratch_cp so we need to map the index values. 496 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 497 } 498 (*merge_cp_length_p)++; 499 } break; 500 501 // this is an indirect CP entry so it needs special handling 502 case JVM_CONSTANT_Dynamic: // fall through 503 case JVM_CONSTANT_InvokeDynamic: 504 { 505 // Index of the bootstrap specifier in the operands array 506 int old_bs_i = scratch_cp->invoke_dynamic_bootstrap_specifier_index(scratch_i); 507 int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p, 508 merge_cp_length_p, THREAD); 509 // The bootstrap method NameAndType_info index 510 int old_ref_i = scratch_cp->invoke_dynamic_name_and_type_ref_index_at(scratch_i); 511 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p, 512 merge_cp_length_p, THREAD); 513 if (new_bs_i != old_bs_i) { 514 log_trace(redefine, class, constantpool) 515 ("Dynamic entry@%d bootstrap_method_attr_index change: %d to %d", 516 *merge_cp_length_p, old_bs_i, new_bs_i); 517 } 518 if (new_ref_i != old_ref_i) { 519 log_trace(redefine, class, constantpool) 520 ("Dynamic entry@%d name_and_type_index change: %d to %d", *merge_cp_length_p, old_ref_i, new_ref_i); 521 } 522 523 if (scratch_cp->tag_at(scratch_i).is_dynamic_constant()) 524 (*merge_cp_p)->dynamic_constant_at_put(*merge_cp_length_p, new_bs_i, new_ref_i); 525 else 526 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, 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 // At this stage, Class or UnresolvedClass could be in scratch_cp, but not 536 // ClassIndex 537 case JVM_CONSTANT_ClassIndex: // fall through 538 539 // Invalid is used as the tag for the second constant pool entry 540 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should 541 // not be seen by itself. 542 case JVM_CONSTANT_Invalid: // fall through 543 544 // At this stage, String could be here, but not StringIndex 545 case JVM_CONSTANT_StringIndex: // fall through 546 547 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be 548 // here 549 case JVM_CONSTANT_UnresolvedClassInError: // fall through 550 551 default: 552 { 553 // leave a breadcrumb 554 jbyte bad_value = scratch_cp->tag_at(scratch_i).value(); 555 ShouldNotReachHere(); 556 } break; 557 } // end switch tag value 558 } // end append_entry() 559 560 561 int VM_RedefineClasses::find_or_append_indirect_entry(const constantPoolHandle& scratch_cp, 562 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) { 563 564 int new_ref_i = ref_i; 565 bool match = (ref_i < *merge_cp_length_p) && 566 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i, THREAD); 567 568 if (!match) { 569 // forward reference in *merge_cp_p or not a direct match 570 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p, THREAD); 571 if (found_i != 0) { 572 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree"); 573 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry. 574 new_ref_i = found_i; 575 map_index(scratch_cp, ref_i, found_i); 576 } else { 577 // no match found so we have to append this entry to *merge_cp_p 578 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p, THREAD); 579 // The above call to append_entry() can only append one entry 580 // so the post call query of *merge_cp_length_p is only for 581 // the sake of consistency. 582 new_ref_i = *merge_cp_length_p - 1; 583 } 584 } 585 586 return new_ref_i; 587 } // end find_or_append_indirect_entry() 588 589 590 // Append a bootstrap specifier into the merge_cp operands that is semantically equal 591 // to the scratch_cp operands bootstrap specifier passed by the old_bs_i index. 592 // Recursively append new merge_cp entries referenced by the new bootstrap specifier. 593 void VM_RedefineClasses::append_operand(const constantPoolHandle& scratch_cp, int old_bs_i, 594 constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) { 595 596 int old_ref_i = scratch_cp->operand_bootstrap_method_ref_index_at(old_bs_i); 597 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p, 598 merge_cp_length_p, THREAD); 599 if (new_ref_i != old_ref_i) { 600 log_trace(redefine, class, constantpool) 601 ("operands entry@%d bootstrap method ref_index change: %d to %d", _operands_cur_length, old_ref_i, new_ref_i); 602 } 603 604 Array<u2>* merge_ops = (*merge_cp_p)->operands(); 605 int new_bs_i = _operands_cur_length; 606 // We have _operands_cur_length == 0 when the merge_cp operands is empty yet. 607 // However, the operand_offset_at(0) was set in the extend_operands() call. 608 int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0) 609 : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1); 610 int argc = scratch_cp->operand_argument_count_at(old_bs_i); 611 612 ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base); 613 merge_ops->at_put(new_base++, new_ref_i); 614 merge_ops->at_put(new_base++, argc); 615 616 for (int i = 0; i < argc; i++) { 617 int old_arg_ref_i = scratch_cp->operand_argument_index_at(old_bs_i, i); 618 int new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p, 619 merge_cp_length_p, THREAD); 620 merge_ops->at_put(new_base++, new_arg_ref_i); 621 if (new_arg_ref_i != old_arg_ref_i) { 622 log_trace(redefine, class, constantpool) 623 ("operands entry@%d bootstrap method argument ref_index change: %d to %d", 624 _operands_cur_length, old_arg_ref_i, new_arg_ref_i); 625 } 626 } 627 if (old_bs_i != _operands_cur_length) { 628 // The bootstrap specifier in *merge_cp_p is at a different index than 629 // that in scratch_cp so we need to map the index values. 630 map_operand_index(old_bs_i, new_bs_i); 631 } 632 _operands_cur_length++; 633 } // end append_operand() 634 635 636 int VM_RedefineClasses::find_or_append_operand(const constantPoolHandle& scratch_cp, 637 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) { 638 639 int new_bs_i = old_bs_i; // bootstrap specifier index 640 bool match = (old_bs_i < _operands_cur_length) && 641 scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i, THREAD); 642 643 if (!match) { 644 // forward reference in *merge_cp_p or not a direct match 645 int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p, 646 _operands_cur_length, THREAD); 647 if (found_i != -1) { 648 guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree"); 649 // found a matching operand somewhere else in *merge_cp_p so just need a mapping 650 new_bs_i = found_i; 651 map_operand_index(old_bs_i, found_i); 652 } else { 653 // no match found so we have to append this bootstrap specifier to *merge_cp_p 654 append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p, THREAD); 655 new_bs_i = _operands_cur_length - 1; 656 } 657 } 658 return new_bs_i; 659 } // end find_or_append_operand() 660 661 662 void VM_RedefineClasses::finalize_operands_merge(const constantPoolHandle& merge_cp, TRAPS) { 663 if (merge_cp->operands() == NULL) { 664 return; 665 } 666 // Shrink the merge_cp operands 667 merge_cp->shrink_operands(_operands_cur_length, CHECK); 668 669 if (log_is_enabled(Trace, redefine, class, constantpool)) { 670 // don't want to loop unless we are tracing 671 int count = 0; 672 for (int i = 1; i < _operands_index_map_p->length(); i++) { 673 int value = _operands_index_map_p->at(i); 674 if (value != -1) { 675 log_trace(redefine, class, constantpool)("operands_index_map[%d]: old=%d new=%d", count, i, value); 676 count++; 677 } 678 } 679 } 680 // Clean-up 681 _operands_index_map_p = NULL; 682 _operands_cur_length = 0; 683 _operands_index_map_count = 0; 684 } // end finalize_operands_merge() 685 686 687 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions( 688 InstanceKlass* the_class, 689 InstanceKlass* scratch_class) { 690 int i; 691 692 // Check superclasses, or rather their names, since superclasses themselves can be 693 // requested to replace. 694 // Check for NULL superclass first since this might be java.lang.Object 695 if (the_class->super() != scratch_class->super() && 696 (the_class->super() == NULL || scratch_class->super() == NULL || 697 the_class->super()->name() != 698 scratch_class->super()->name())) { 699 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 700 } 701 702 // Check if the number, names and order of directly implemented interfaces are the same. 703 // I think in principle we should just check if the sets of names of directly implemented 704 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the 705 // .java file, also changes in .class file) should not matter. However, comparing sets is 706 // technically a bit more difficult, and, more importantly, I am not sure at present that the 707 // order of interfaces does not matter on the implementation level, i.e. that the VM does not 708 // rely on it somewhere. 709 Array<Klass*>* k_interfaces = the_class->local_interfaces(); 710 Array<Klass*>* k_new_interfaces = scratch_class->local_interfaces(); 711 int n_intfs = k_interfaces->length(); 712 if (n_intfs != k_new_interfaces->length()) { 713 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 714 } 715 for (i = 0; i < n_intfs; i++) { 716 if (k_interfaces->at(i)->name() != 717 k_new_interfaces->at(i)->name()) { 718 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 719 } 720 } 721 722 // Check whether class is in the error init state. 723 if (the_class->is_in_error_state()) { 724 // TBD #5057930: special error code is needed in 1.6 725 return JVMTI_ERROR_INVALID_CLASS; 726 } 727 728 // Check whether class modifiers are the same. 729 jushort old_flags = (jushort) the_class->access_flags().get_flags(); 730 jushort new_flags = (jushort) scratch_class->access_flags().get_flags(); 731 if (old_flags != new_flags) { 732 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED; 733 } 734 735 // Check if the number, names, types and order of fields declared in these classes 736 // are the same. 737 JavaFieldStream old_fs(the_class); 738 JavaFieldStream new_fs(scratch_class); 739 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) { 740 // access 741 old_flags = old_fs.access_flags().as_short(); 742 new_flags = new_fs.access_flags().as_short(); 743 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) { 744 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 745 } 746 // offset 747 if (old_fs.offset() != new_fs.offset()) { 748 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 749 } 750 // name and signature 751 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index()); 752 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index()); 753 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index()); 754 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index()); 755 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) { 756 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 757 } 758 } 759 760 // If both streams aren't done then we have a differing number of 761 // fields. 762 if (!old_fs.done() || !new_fs.done()) { 763 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 764 } 765 766 // Do a parallel walk through the old and new methods. Detect 767 // cases where they match (exist in both), have been added in 768 // the new methods, or have been deleted (exist only in the 769 // old methods). The class file parser places methods in order 770 // by method name, but does not order overloaded methods by 771 // signature. In order to determine what fate befell the methods, 772 // this code places the overloaded new methods that have matching 773 // old methods in the same order as the old methods and places 774 // new overloaded methods at the end of overloaded methods of 775 // that name. The code for this order normalization is adapted 776 // from the algorithm used in InstanceKlass::find_method(). 777 // Since we are swapping out of order entries as we find them, 778 // we only have to search forward through the overloaded methods. 779 // Methods which are added and have the same name as an existing 780 // method (but different signature) will be put at the end of 781 // the methods with that name, and the name mismatch code will 782 // handle them. 783 Array<Method*>* k_old_methods(the_class->methods()); 784 Array<Method*>* k_new_methods(scratch_class->methods()); 785 int n_old_methods = k_old_methods->length(); 786 int n_new_methods = k_new_methods->length(); 787 Thread* thread = Thread::current(); 788 789 int ni = 0; 790 int oi = 0; 791 while (true) { 792 Method* k_old_method; 793 Method* k_new_method; 794 enum { matched, added, deleted, undetermined } method_was = undetermined; 795 796 if (oi >= n_old_methods) { 797 if (ni >= n_new_methods) { 798 break; // we've looked at everything, done 799 } 800 // New method at the end 801 k_new_method = k_new_methods->at(ni); 802 method_was = added; 803 } else if (ni >= n_new_methods) { 804 // Old method, at the end, is deleted 805 k_old_method = k_old_methods->at(oi); 806 method_was = deleted; 807 } else { 808 // There are more methods in both the old and new lists 809 k_old_method = k_old_methods->at(oi); 810 k_new_method = k_new_methods->at(ni); 811 if (k_old_method->name() != k_new_method->name()) { 812 // Methods are sorted by method name, so a mismatch means added 813 // or deleted 814 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) { 815 method_was = added; 816 } else { 817 method_was = deleted; 818 } 819 } else if (k_old_method->signature() == k_new_method->signature()) { 820 // Both the name and signature match 821 method_was = matched; 822 } else { 823 // The name matches, but the signature doesn't, which means we have to 824 // search forward through the new overloaded methods. 825 int nj; // outside the loop for post-loop check 826 for (nj = ni + 1; nj < n_new_methods; nj++) { 827 Method* m = k_new_methods->at(nj); 828 if (k_old_method->name() != m->name()) { 829 // reached another method name so no more overloaded methods 830 method_was = deleted; 831 break; 832 } 833 if (k_old_method->signature() == m->signature()) { 834 // found a match so swap the methods 835 k_new_methods->at_put(ni, m); 836 k_new_methods->at_put(nj, k_new_method); 837 k_new_method = m; 838 method_was = matched; 839 break; 840 } 841 } 842 843 if (nj >= n_new_methods) { 844 // reached the end without a match; so method was deleted 845 method_was = deleted; 846 } 847 } 848 } 849 850 switch (method_was) { 851 case matched: 852 // methods match, be sure modifiers do too 853 old_flags = (jushort) k_old_method->access_flags().get_flags(); 854 new_flags = (jushort) k_new_method->access_flags().get_flags(); 855 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) { 856 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED; 857 } 858 { 859 u2 new_num = k_new_method->method_idnum(); 860 u2 old_num = k_old_method->method_idnum(); 861 if (new_num != old_num) { 862 Method* idnum_owner = scratch_class->method_with_idnum(old_num); 863 if (idnum_owner != NULL) { 864 // There is already a method assigned this idnum -- switch them 865 // Take current and original idnum from the new_method 866 idnum_owner->set_method_idnum(new_num); 867 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum()); 868 } 869 // Take current and original idnum from the old_method 870 k_new_method->set_method_idnum(old_num); 871 k_new_method->set_orig_method_idnum(k_old_method->orig_method_idnum()); 872 if (thread->has_pending_exception()) { 873 return JVMTI_ERROR_OUT_OF_MEMORY; 874 } 875 } 876 } 877 log_trace(redefine, class, normalize) 878 ("Method matched: new: %s [%d] == old: %s [%d]", 879 k_new_method->name_and_sig_as_C_string(), ni, k_old_method->name_and_sig_as_C_string(), oi); 880 // advance to next pair of methods 881 ++oi; 882 ++ni; 883 break; 884 case added: 885 // method added, see if it is OK 886 new_flags = (jushort) k_new_method->access_flags().get_flags(); 887 if ((new_flags & JVM_ACC_PRIVATE) == 0 888 // hack: private should be treated as final, but alas 889 || (new_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0 890 ) { 891 // new methods must be private 892 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED; 893 } 894 { 895 u2 num = the_class->next_method_idnum(); 896 if (num == ConstMethod::UNSET_IDNUM) { 897 // cannot add any more methods 898 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED; 899 } 900 u2 new_num = k_new_method->method_idnum(); 901 Method* idnum_owner = scratch_class->method_with_idnum(num); 902 if (idnum_owner != NULL) { 903 // There is already a method assigned this idnum -- switch them 904 // Take current and original idnum from the new_method 905 idnum_owner->set_method_idnum(new_num); 906 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum()); 907 } 908 k_new_method->set_method_idnum(num); 909 k_new_method->set_orig_method_idnum(num); 910 if (thread->has_pending_exception()) { 911 return JVMTI_ERROR_OUT_OF_MEMORY; 912 } 913 } 914 log_trace(redefine, class, normalize) 915 ("Method added: new: %s [%d]", k_new_method->name_and_sig_as_C_string(), ni); 916 ++ni; // advance to next new method 917 break; 918 case deleted: 919 // method deleted, see if it is OK 920 old_flags = (jushort) k_old_method->access_flags().get_flags(); 921 if ((old_flags & JVM_ACC_PRIVATE) == 0 922 // hack: private should be treated as final, but alas 923 || (old_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0 924 ) { 925 // deleted methods must be private 926 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED; 927 } 928 log_trace(redefine, class, normalize) 929 ("Method deleted: old: %s [%d]", k_old_method->name_and_sig_as_C_string(), oi); 930 ++oi; // advance to next old method 931 break; 932 default: 933 ShouldNotReachHere(); 934 } 935 } 936 937 return JVMTI_ERROR_NONE; 938 } 939 940 941 // Find new constant pool index value for old constant pool index value 942 // by seaching the index map. Returns zero (0) if there is no mapped 943 // value for the old constant pool index. 944 int VM_RedefineClasses::find_new_index(int old_index) { 945 if (_index_map_count == 0) { 946 // map is empty so nothing can be found 947 return 0; 948 } 949 950 if (old_index < 1 || old_index >= _index_map_p->length()) { 951 // The old_index is out of range so it is not mapped. This should 952 // not happen in regular constant pool merging use, but it can 953 // happen if a corrupt annotation is processed. 954 return 0; 955 } 956 957 int value = _index_map_p->at(old_index); 958 if (value == -1) { 959 // the old_index is not mapped 960 return 0; 961 } 962 963 return value; 964 } // end find_new_index() 965 966 967 // Find new bootstrap specifier index value for old bootstrap specifier index 968 // value by seaching the index map. Returns unused index (-1) if there is 969 // no mapped value for the old bootstrap specifier index. 970 int VM_RedefineClasses::find_new_operand_index(int old_index) { 971 if (_operands_index_map_count == 0) { 972 // map is empty so nothing can be found 973 return -1; 974 } 975 976 if (old_index == -1 || old_index >= _operands_index_map_p->length()) { 977 // The old_index is out of range so it is not mapped. 978 // This should not happen in regular constant pool merging use. 979 return -1; 980 } 981 982 int value = _operands_index_map_p->at(old_index); 983 if (value == -1) { 984 // the old_index is not mapped 985 return -1; 986 } 987 988 return value; 989 } // end find_new_operand_index() 990 991 992 // Returns true if the current mismatch is due to a resolved/unresolved 993 // class pair. Otherwise, returns false. 994 bool VM_RedefineClasses::is_unresolved_class_mismatch(const constantPoolHandle& cp1, 995 int index1, const constantPoolHandle& cp2, int index2) { 996 997 jbyte t1 = cp1->tag_at(index1).value(); 998 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) { 999 return false; // wrong entry type; not our special case 1000 } 1001 1002 jbyte t2 = cp2->tag_at(index2).value(); 1003 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) { 1004 return false; // wrong entry type; not our special case 1005 } 1006 1007 if (t1 == t2) { 1008 return false; // not a mismatch; not our special case 1009 } 1010 1011 char *s1 = cp1->klass_name_at(index1)->as_C_string(); 1012 char *s2 = cp2->klass_name_at(index2)->as_C_string(); 1013 if (strcmp(s1, s2) != 0) { 1014 return false; // strings don't match; not our special case 1015 } 1016 1017 return true; // made it through the gauntlet; this is our special case 1018 } // end is_unresolved_class_mismatch() 1019 1020 1021 jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) { 1022 1023 // For consistency allocate memory using os::malloc wrapper. 1024 _scratch_classes = (InstanceKlass**) 1025 os::malloc(sizeof(InstanceKlass*) * _class_count, mtClass); 1026 if (_scratch_classes == NULL) { 1027 return JVMTI_ERROR_OUT_OF_MEMORY; 1028 } 1029 // Zero initialize the _scratch_classes array. 1030 for (int i = 0; i < _class_count; i++) { 1031 _scratch_classes[i] = NULL; 1032 } 1033 1034 ResourceMark rm(THREAD); 1035 1036 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current()); 1037 // state can only be NULL if the current thread is exiting which 1038 // should not happen since we're trying to do a RedefineClasses 1039 guarantee(state != NULL, "exiting thread calling load_new_class_versions"); 1040 for (int i = 0; i < _class_count; i++) { 1041 // Create HandleMark so that any handles created while loading new class 1042 // versions are deleted. Constant pools are deallocated while merging 1043 // constant pools 1044 HandleMark hm(THREAD); 1045 InstanceKlass* the_class = get_ik(_class_defs[i].klass); 1046 Symbol* the_class_sym = the_class->name(); 1047 1048 log_debug(redefine, class, load) 1049 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)", 1050 the_class->external_name(), _class_load_kind, os::available_memory() >> 10); 1051 1052 ClassFileStream st((u1*)_class_defs[i].class_bytes, 1053 _class_defs[i].class_byte_count, 1054 "__VM_RedefineClasses__", 1055 ClassFileStream::verify); 1056 1057 // Parse the stream. 1058 Handle the_class_loader(THREAD, the_class->class_loader()); 1059 Handle protection_domain(THREAD, the_class->protection_domain()); 1060 // Set redefined class handle in JvmtiThreadState class. 1061 // This redefined class is sent to agent event handler for class file 1062 // load hook event. 1063 state->set_class_being_redefined(the_class, _class_load_kind); 1064 1065 InstanceKlass* scratch_class = SystemDictionary::parse_stream( 1066 the_class_sym, 1067 the_class_loader, 1068 protection_domain, 1069 &st, 1070 THREAD); 1071 // Clear class_being_redefined just to be sure. 1072 state->clear_class_being_redefined(); 1073 1074 // TODO: if this is retransform, and nothing changed we can skip it 1075 1076 // Need to clean up allocated InstanceKlass if there's an error so assign 1077 // the result here. Caller deallocates all the scratch classes in case of 1078 // an error. 1079 _scratch_classes[i] = scratch_class; 1080 1081 if (HAS_PENDING_EXCEPTION) { 1082 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1083 log_info(redefine, class, load, exceptions)("parse_stream exception: '%s'", ex_name->as_C_string()); 1084 CLEAR_PENDING_EXCEPTION; 1085 1086 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) { 1087 return JVMTI_ERROR_UNSUPPORTED_VERSION; 1088 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) { 1089 return JVMTI_ERROR_INVALID_CLASS_FORMAT; 1090 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) { 1091 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION; 1092 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) { 1093 // The message will be "XXX (wrong name: YYY)" 1094 return JVMTI_ERROR_NAMES_DONT_MATCH; 1095 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1096 return JVMTI_ERROR_OUT_OF_MEMORY; 1097 } else { // Just in case more exceptions can be thrown.. 1098 return JVMTI_ERROR_FAILS_VERIFICATION; 1099 } 1100 } 1101 1102 // Ensure class is linked before redefine 1103 if (!the_class->is_linked()) { 1104 the_class->link_class(THREAD); 1105 if (HAS_PENDING_EXCEPTION) { 1106 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1107 log_info(redefine, class, load, exceptions)("link_class exception: '%s'", ex_name->as_C_string()); 1108 CLEAR_PENDING_EXCEPTION; 1109 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1110 return JVMTI_ERROR_OUT_OF_MEMORY; 1111 } else { 1112 return JVMTI_ERROR_INTERNAL; 1113 } 1114 } 1115 } 1116 1117 // Do the validity checks in compare_and_normalize_class_versions() 1118 // before verifying the byte codes. By doing these checks first, we 1119 // limit the number of functions that require redirection from 1120 // the_class to scratch_class. In particular, we don't have to 1121 // modify JNI GetSuperclass() and thus won't change its performance. 1122 jvmtiError res = compare_and_normalize_class_versions(the_class, 1123 scratch_class); 1124 if (res != JVMTI_ERROR_NONE) { 1125 return res; 1126 } 1127 1128 // verify what the caller passed us 1129 { 1130 // The bug 6214132 caused the verification to fail. 1131 // Information about the_class and scratch_class is temporarily 1132 // recorded into jvmtiThreadState. This data is used to redirect 1133 // the_class to scratch_class in the JVM_* functions called by the 1134 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed 1135 // description. 1136 RedefineVerifyMark rvm(the_class, scratch_class, state); 1137 Verifier::verify( 1138 scratch_class, Verifier::ThrowException, true, THREAD); 1139 } 1140 1141 if (HAS_PENDING_EXCEPTION) { 1142 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1143 log_info(redefine, class, load, exceptions)("verify_byte_codes exception: '%s'", ex_name->as_C_string()); 1144 CLEAR_PENDING_EXCEPTION; 1145 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1146 return JVMTI_ERROR_OUT_OF_MEMORY; 1147 } else { 1148 // tell the caller the bytecodes are bad 1149 return JVMTI_ERROR_FAILS_VERIFICATION; 1150 } 1151 } 1152 1153 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD); 1154 if (HAS_PENDING_EXCEPTION) { 1155 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1156 log_info(redefine, class, load, exceptions)("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string()); 1157 CLEAR_PENDING_EXCEPTION; 1158 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1159 return JVMTI_ERROR_OUT_OF_MEMORY; 1160 } else { 1161 return JVMTI_ERROR_INTERNAL; 1162 } 1163 } 1164 1165 if (VerifyMergedCPBytecodes) { 1166 // verify what we have done during constant pool merging 1167 { 1168 RedefineVerifyMark rvm(the_class, scratch_class, state); 1169 Verifier::verify(scratch_class, Verifier::ThrowException, true, THREAD); 1170 } 1171 1172 if (HAS_PENDING_EXCEPTION) { 1173 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1174 log_info(redefine, class, load, exceptions) 1175 ("verify_byte_codes post merge-CP exception: '%s'", ex_name->as_C_string()); 1176 CLEAR_PENDING_EXCEPTION; 1177 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1178 return JVMTI_ERROR_OUT_OF_MEMORY; 1179 } else { 1180 // tell the caller that constant pool merging screwed up 1181 return JVMTI_ERROR_INTERNAL; 1182 } 1183 } 1184 } 1185 1186 Rewriter::rewrite(scratch_class, THREAD); 1187 if (!HAS_PENDING_EXCEPTION) { 1188 scratch_class->link_methods(THREAD); 1189 } 1190 if (HAS_PENDING_EXCEPTION) { 1191 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1192 log_info(redefine, class, load, exceptions) 1193 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string()); 1194 CLEAR_PENDING_EXCEPTION; 1195 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1196 return JVMTI_ERROR_OUT_OF_MEMORY; 1197 } else { 1198 return JVMTI_ERROR_INTERNAL; 1199 } 1200 } 1201 1202 log_debug(redefine, class, load) 1203 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)", the_class->external_name(), os::available_memory() >> 10); 1204 } 1205 1206 return JVMTI_ERROR_NONE; 1207 } 1208 1209 1210 // Map old_index to new_index as needed. scratch_cp is only needed 1211 // for log calls. 1212 void VM_RedefineClasses::map_index(const constantPoolHandle& scratch_cp, 1213 int old_index, int new_index) { 1214 if (find_new_index(old_index) != 0) { 1215 // old_index is already mapped 1216 return; 1217 } 1218 1219 if (old_index == new_index) { 1220 // no mapping is needed 1221 return; 1222 } 1223 1224 _index_map_p->at_put(old_index, new_index); 1225 _index_map_count++; 1226 1227 log_trace(redefine, class, constantpool) 1228 ("mapped tag %d at index %d to %d", scratch_cp->tag_at(old_index).value(), old_index, new_index); 1229 } // end map_index() 1230 1231 1232 // Map old_index to new_index as needed. 1233 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) { 1234 if (find_new_operand_index(old_index) != -1) { 1235 // old_index is already mapped 1236 return; 1237 } 1238 1239 if (old_index == new_index) { 1240 // no mapping is needed 1241 return; 1242 } 1243 1244 _operands_index_map_p->at_put(old_index, new_index); 1245 _operands_index_map_count++; 1246 1247 log_trace(redefine, class, constantpool)("mapped bootstrap specifier at index %d to %d", old_index, new_index); 1248 } // end map_index() 1249 1250 1251 // Merge old_cp and scratch_cp and return the results of the merge via 1252 // merge_cp_p. The number of entries in *merge_cp_p is returned via 1253 // merge_cp_length_p. The entries in old_cp occupy the same locations 1254 // in *merge_cp_p. Also creates a map of indices from entries in 1255 // scratch_cp to the corresponding entry in *merge_cp_p. Index map 1256 // entries are only created for entries in scratch_cp that occupy a 1257 // different location in *merged_cp_p. 1258 bool VM_RedefineClasses::merge_constant_pools(const constantPoolHandle& old_cp, 1259 const constantPoolHandle& scratch_cp, constantPoolHandle *merge_cp_p, 1260 int *merge_cp_length_p, TRAPS) { 1261 1262 if (merge_cp_p == NULL) { 1263 assert(false, "caller must provide scratch constantPool"); 1264 return false; // robustness 1265 } 1266 if (merge_cp_length_p == NULL) { 1267 assert(false, "caller must provide scratch CP length"); 1268 return false; // robustness 1269 } 1270 // Worst case we need old_cp->length() + scratch_cp()->length(), 1271 // but the caller might be smart so make sure we have at least 1272 // the minimum. 1273 if ((*merge_cp_p)->length() < old_cp->length()) { 1274 assert(false, "merge area too small"); 1275 return false; // robustness 1276 } 1277 1278 log_info(redefine, class, constantpool)("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(), scratch_cp->length()); 1279 1280 { 1281 // Pass 0: 1282 // The old_cp is copied to *merge_cp_p; this means that any code 1283 // using old_cp does not have to change. This work looks like a 1284 // perfect fit for ConstantPool*::copy_cp_to(), but we need to 1285 // handle one special case: 1286 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass 1287 // This will make verification happy. 1288 1289 int old_i; // index into old_cp 1290 1291 // index zero (0) is not used in constantPools 1292 for (old_i = 1; old_i < old_cp->length(); old_i++) { 1293 // leave debugging crumb 1294 jbyte old_tag = old_cp->tag_at(old_i).value(); 1295 switch (old_tag) { 1296 case JVM_CONSTANT_Class: 1297 case JVM_CONSTANT_UnresolvedClass: 1298 // revert the copy to JVM_CONSTANT_UnresolvedClass 1299 // May be resolving while calling this so do the same for 1300 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition) 1301 (*merge_cp_p)->temp_unresolved_klass_at_put(old_i, 1302 old_cp->klass_name_index_at(old_i)); 1303 break; 1304 1305 case JVM_CONSTANT_Double: 1306 case JVM_CONSTANT_Long: 1307 // just copy the entry to *merge_cp_p, but double and long take 1308 // two constant pool entries 1309 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0); 1310 old_i++; 1311 break; 1312 1313 default: 1314 // just copy the entry to *merge_cp_p 1315 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0); 1316 break; 1317 } 1318 } // end for each old_cp entry 1319 1320 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_0); 1321 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_0); 1322 1323 // We don't need to sanity check that *merge_cp_length_p is within 1324 // *merge_cp_p bounds since we have the minimum on-entry check above. 1325 (*merge_cp_length_p) = old_i; 1326 } 1327 1328 // merge_cp_len should be the same as old_cp->length() at this point 1329 // so this trace message is really a "warm-and-breathing" message. 1330 log_debug(redefine, class, constantpool)("after pass 0: merge_cp_len=%d", *merge_cp_length_p); 1331 1332 int scratch_i; // index into scratch_cp 1333 { 1334 // Pass 1a: 1335 // Compare scratch_cp entries to the old_cp entries that we have 1336 // already copied to *merge_cp_p. In this pass, we are eliminating 1337 // exact duplicates (matching entry at same index) so we only 1338 // compare entries in the common indice range. 1339 int increment = 1; 1340 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length()); 1341 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) { 1342 switch (scratch_cp->tag_at(scratch_i).value()) { 1343 case JVM_CONSTANT_Double: 1344 case JVM_CONSTANT_Long: 1345 // double and long take two constant pool entries 1346 increment = 2; 1347 break; 1348 1349 default: 1350 increment = 1; 1351 break; 1352 } 1353 1354 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p, 1355 scratch_i, CHECK_0); 1356 if (match) { 1357 // found a match at the same index so nothing more to do 1358 continue; 1359 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i, 1360 *merge_cp_p, scratch_i)) { 1361 // The mismatch in compare_entry_to() above is because of a 1362 // resolved versus unresolved class entry at the same index 1363 // with the same string value. Since Pass 0 reverted any 1364 // class entries to unresolved class entries in *merge_cp_p, 1365 // we go with the unresolved class entry. 1366 continue; 1367 } 1368 1369 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, 1370 CHECK_0); 1371 if (found_i != 0) { 1372 guarantee(found_i != scratch_i, 1373 "compare_entry_to() and find_matching_entry() do not agree"); 1374 1375 // Found a matching entry somewhere else in *merge_cp_p so 1376 // just need a mapping entry. 1377 map_index(scratch_cp, scratch_i, found_i); 1378 continue; 1379 } 1380 1381 // The find_matching_entry() call above could fail to find a match 1382 // due to a resolved versus unresolved class or string entry situation 1383 // like we solved above with the is_unresolved_*_mismatch() calls. 1384 // However, we would have to call is_unresolved_*_mismatch() over 1385 // all of *merge_cp_p (potentially) and that doesn't seem to be 1386 // worth the time. 1387 1388 // No match found so we have to append this entry and any unique 1389 // referenced entries to *merge_cp_p. 1390 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p, 1391 CHECK_0); 1392 } 1393 } 1394 1395 log_debug(redefine, class, constantpool) 1396 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", 1397 *merge_cp_length_p, scratch_i, _index_map_count); 1398 1399 if (scratch_i < scratch_cp->length()) { 1400 // Pass 1b: 1401 // old_cp is smaller than scratch_cp so there are entries in 1402 // scratch_cp that we have not yet processed. We take care of 1403 // those now. 1404 int increment = 1; 1405 for (; scratch_i < scratch_cp->length(); scratch_i += increment) { 1406 switch (scratch_cp->tag_at(scratch_i).value()) { 1407 case JVM_CONSTANT_Double: 1408 case JVM_CONSTANT_Long: 1409 // double and long take two constant pool entries 1410 increment = 2; 1411 break; 1412 1413 default: 1414 increment = 1; 1415 break; 1416 } 1417 1418 int found_i = 1419 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0); 1420 if (found_i != 0) { 1421 // Found a matching entry somewhere else in *merge_cp_p so 1422 // just need a mapping entry. 1423 map_index(scratch_cp, scratch_i, found_i); 1424 continue; 1425 } 1426 1427 // No match found so we have to append this entry and any unique 1428 // referenced entries to *merge_cp_p. 1429 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p, 1430 CHECK_0); 1431 } 1432 1433 log_debug(redefine, class, constantpool) 1434 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", 1435 *merge_cp_length_p, scratch_i, _index_map_count); 1436 } 1437 finalize_operands_merge(*merge_cp_p, THREAD); 1438 1439 return true; 1440 } // end merge_constant_pools() 1441 1442 1443 // Scoped object to clean up the constant pool(s) created for merging 1444 class MergeCPCleaner { 1445 ClassLoaderData* _loader_data; 1446 ConstantPool* _cp; 1447 ConstantPool* _scratch_cp; 1448 public: 1449 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) : 1450 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {} 1451 ~MergeCPCleaner() { 1452 _loader_data->add_to_deallocate_list(_cp); 1453 if (_scratch_cp != NULL) { 1454 _loader_data->add_to_deallocate_list(_scratch_cp); 1455 } 1456 } 1457 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; } 1458 }; 1459 1460 // Merge constant pools between the_class and scratch_class and 1461 // potentially rewrite bytecodes in scratch_class to use the merged 1462 // constant pool. 1463 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite( 1464 InstanceKlass* the_class, InstanceKlass* scratch_class, 1465 TRAPS) { 1466 // worst case merged constant pool length is old and new combined 1467 int merge_cp_length = the_class->constants()->length() 1468 + scratch_class->constants()->length(); 1469 1470 // Constant pools are not easily reused so we allocate a new one 1471 // each time. 1472 // merge_cp is created unsafe for concurrent GC processing. It 1473 // should be marked safe before discarding it. Even though 1474 // garbage, if it crosses a card boundary, it may be scanned 1475 // in order to find the start of the first complete object on the card. 1476 ClassLoaderData* loader_data = the_class->class_loader_data(); 1477 ConstantPool* merge_cp_oop = 1478 ConstantPool::allocate(loader_data, 1479 merge_cp_length, 1480 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1481 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop); 1482 1483 HandleMark hm(THREAD); // make sure handles are cleared before 1484 // MergeCPCleaner clears out merge_cp_oop 1485 constantPoolHandle merge_cp(THREAD, merge_cp_oop); 1486 1487 // Get constants() from the old class because it could have been rewritten 1488 // while we were at a safepoint allocating a new constant pool. 1489 constantPoolHandle old_cp(THREAD, the_class->constants()); 1490 constantPoolHandle scratch_cp(THREAD, scratch_class->constants()); 1491 1492 // If the length changed, the class was redefined out from under us. Return 1493 // an error. 1494 if (merge_cp_length != the_class->constants()->length() 1495 + scratch_class->constants()->length()) { 1496 return JVMTI_ERROR_INTERNAL; 1497 } 1498 1499 // Update the version number of the constant pools (may keep scratch_cp) 1500 merge_cp->increment_and_save_version(old_cp->version()); 1501 scratch_cp->increment_and_save_version(old_cp->version()); 1502 1503 ResourceMark rm(THREAD); 1504 _index_map_count = 0; 1505 _index_map_p = new intArray(scratch_cp->length(), scratch_cp->length(), -1); 1506 1507 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands()); 1508 _operands_index_map_count = 0; 1509 int operands_index_map_len = ConstantPool::operand_array_length(scratch_cp->operands()); 1510 _operands_index_map_p = new intArray(operands_index_map_len, operands_index_map_len, -1); 1511 1512 // reference to the cp holder is needed for copy_operands() 1513 merge_cp->set_pool_holder(scratch_class); 1514 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp, 1515 &merge_cp_length, THREAD); 1516 merge_cp->set_pool_holder(NULL); 1517 1518 if (!result) { 1519 // The merge can fail due to memory allocation failure or due 1520 // to robustness checks. 1521 return JVMTI_ERROR_INTERNAL; 1522 } 1523 1524 log_info(redefine, class, constantpool)("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count); 1525 1526 if (_index_map_count == 0) { 1527 // there is nothing to map between the new and merged constant pools 1528 1529 if (old_cp->length() == scratch_cp->length()) { 1530 // The old and new constant pools are the same length and the 1531 // index map is empty. This means that the three constant pools 1532 // are equivalent (but not the same). Unfortunately, the new 1533 // constant pool has not gone through link resolution nor have 1534 // the new class bytecodes gone through constant pool cache 1535 // rewriting so we can't use the old constant pool with the new 1536 // class. 1537 1538 // toss the merged constant pool at return 1539 } else if (old_cp->length() < scratch_cp->length()) { 1540 // The old constant pool has fewer entries than the new constant 1541 // pool and the index map is empty. This means the new constant 1542 // pool is a superset of the old constant pool. However, the old 1543 // class bytecodes have already gone through constant pool cache 1544 // rewriting so we can't use the new constant pool with the old 1545 // class. 1546 1547 // toss the merged constant pool at return 1548 } else { 1549 // The old constant pool has more entries than the new constant 1550 // pool and the index map is empty. This means that both the old 1551 // and merged constant pools are supersets of the new constant 1552 // pool. 1553 1554 // Replace the new constant pool with a shrunken copy of the 1555 // merged constant pool 1556 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, 1557 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1558 // The new constant pool replaces scratch_cp so have cleaner clean it up. 1559 // It can't be cleaned up while there are handles to it. 1560 cp_cleaner.add_scratch_cp(scratch_cp()); 1561 } 1562 } else { 1563 if (log_is_enabled(Trace, redefine, class, constantpool)) { 1564 // don't want to loop unless we are tracing 1565 int count = 0; 1566 for (int i = 1; i < _index_map_p->length(); i++) { 1567 int value = _index_map_p->at(i); 1568 1569 if (value != -1) { 1570 log_trace(redefine, class, constantpool)("index_map[%d]: old=%d new=%d", count, i, value); 1571 count++; 1572 } 1573 } 1574 } 1575 1576 // We have entries mapped between the new and merged constant pools 1577 // so we have to rewrite some constant pool references. 1578 if (!rewrite_cp_refs(scratch_class, THREAD)) { 1579 return JVMTI_ERROR_INTERNAL; 1580 } 1581 1582 // Replace the new constant pool with a shrunken copy of the 1583 // merged constant pool so now the rewritten bytecodes have 1584 // valid references; the previous new constant pool will get 1585 // GCed. 1586 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, 1587 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1588 // The new constant pool replaces scratch_cp so have cleaner clean it up. 1589 // It can't be cleaned up while there are handles to it. 1590 cp_cleaner.add_scratch_cp(scratch_cp()); 1591 } 1592 1593 return JVMTI_ERROR_NONE; 1594 } // end merge_cp_and_rewrite() 1595 1596 1597 // Rewrite constant pool references in klass scratch_class. 1598 bool VM_RedefineClasses::rewrite_cp_refs(InstanceKlass* scratch_class, 1599 TRAPS) { 1600 1601 // rewrite constant pool references in the methods: 1602 if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) { 1603 // propagate failure back to caller 1604 return false; 1605 } 1606 1607 // rewrite constant pool references in the class_annotations: 1608 if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) { 1609 // propagate failure back to caller 1610 return false; 1611 } 1612 1613 // rewrite constant pool references in the fields_annotations: 1614 if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) { 1615 // propagate failure back to caller 1616 return false; 1617 } 1618 1619 // rewrite constant pool references in the methods_annotations: 1620 if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) { 1621 // propagate failure back to caller 1622 return false; 1623 } 1624 1625 // rewrite constant pool references in the methods_parameter_annotations: 1626 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class, 1627 THREAD)) { 1628 // propagate failure back to caller 1629 return false; 1630 } 1631 1632 // rewrite constant pool references in the methods_default_annotations: 1633 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class, 1634 THREAD)) { 1635 // propagate failure back to caller 1636 return false; 1637 } 1638 1639 // rewrite constant pool references in the class_type_annotations: 1640 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class, THREAD)) { 1641 // propagate failure back to caller 1642 return false; 1643 } 1644 1645 // rewrite constant pool references in the fields_type_annotations: 1646 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class, THREAD)) { 1647 // propagate failure back to caller 1648 return false; 1649 } 1650 1651 // rewrite constant pool references in the methods_type_annotations: 1652 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class, THREAD)) { 1653 // propagate failure back to caller 1654 return false; 1655 } 1656 1657 // There can be type annotations in the Code part of a method_info attribute. 1658 // These annotations are not accessible, even by reflection. 1659 // Currently they are not even parsed by the ClassFileParser. 1660 // If runtime access is added they will also need to be rewritten. 1661 1662 // rewrite source file name index: 1663 u2 source_file_name_idx = scratch_class->source_file_name_index(); 1664 if (source_file_name_idx != 0) { 1665 u2 new_source_file_name_idx = find_new_index(source_file_name_idx); 1666 if (new_source_file_name_idx != 0) { 1667 scratch_class->set_source_file_name_index(new_source_file_name_idx); 1668 } 1669 } 1670 1671 // rewrite class generic signature index: 1672 u2 generic_signature_index = scratch_class->generic_signature_index(); 1673 if (generic_signature_index != 0) { 1674 u2 new_generic_signature_index = find_new_index(generic_signature_index); 1675 if (new_generic_signature_index != 0) { 1676 scratch_class->set_generic_signature_index(new_generic_signature_index); 1677 } 1678 } 1679 1680 return true; 1681 } // end rewrite_cp_refs() 1682 1683 // Rewrite constant pool references in the methods. 1684 bool VM_RedefineClasses::rewrite_cp_refs_in_methods( 1685 InstanceKlass* scratch_class, TRAPS) { 1686 1687 Array<Method*>* methods = scratch_class->methods(); 1688 1689 if (methods == NULL || methods->length() == 0) { 1690 // no methods so nothing to do 1691 return true; 1692 } 1693 1694 // rewrite constant pool references in the methods: 1695 for (int i = methods->length() - 1; i >= 0; i--) { 1696 methodHandle method(THREAD, methods->at(i)); 1697 methodHandle new_method; 1698 rewrite_cp_refs_in_method(method, &new_method, THREAD); 1699 if (!new_method.is_null()) { 1700 // the method has been replaced so save the new method version 1701 // even in the case of an exception. original method is on the 1702 // deallocation list. 1703 methods->at_put(i, new_method()); 1704 } 1705 if (HAS_PENDING_EXCEPTION) { 1706 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1707 log_info(redefine, class, load, exceptions)("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string()); 1708 // Need to clear pending exception here as the super caller sets 1709 // the JVMTI_ERROR_INTERNAL if the returned value is false. 1710 CLEAR_PENDING_EXCEPTION; 1711 return false; 1712 } 1713 } 1714 1715 return true; 1716 } 1717 1718 1719 // Rewrite constant pool references in the specific method. This code 1720 // was adapted from Rewriter::rewrite_method(). 1721 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method, 1722 methodHandle *new_method_p, TRAPS) { 1723 1724 *new_method_p = methodHandle(); // default is no new method 1725 1726 // We cache a pointer to the bytecodes here in code_base. If GC 1727 // moves the Method*, then the bytecodes will also move which 1728 // will likely cause a crash. We create a NoSafepointVerifier 1729 // object to detect whether we pass a possible safepoint in this 1730 // code block. 1731 NoSafepointVerifier nsv; 1732 1733 // Bytecodes and their length 1734 address code_base = method->code_base(); 1735 int code_length = method->code_size(); 1736 1737 int bc_length; 1738 for (int bci = 0; bci < code_length; bci += bc_length) { 1739 address bcp = code_base + bci; 1740 Bytecodes::Code c = (Bytecodes::Code)(*bcp); 1741 1742 bc_length = Bytecodes::length_for(c); 1743 if (bc_length == 0) { 1744 // More complicated bytecodes report a length of zero so 1745 // we have to try again a slightly different way. 1746 bc_length = Bytecodes::length_at(method(), bcp); 1747 } 1748 1749 assert(bc_length != 0, "impossible bytecode length"); 1750 1751 switch (c) { 1752 case Bytecodes::_ldc: 1753 { 1754 int cp_index = *(bcp + 1); 1755 int new_index = find_new_index(cp_index); 1756 1757 if (StressLdcRewrite && new_index == 0) { 1758 // If we are stressing ldc -> ldc_w rewriting, then we 1759 // always need a new_index value. 1760 new_index = cp_index; 1761 } 1762 if (new_index != 0) { 1763 // the original index is mapped so we have more work to do 1764 if (!StressLdcRewrite && new_index <= max_jubyte) { 1765 // The new value can still use ldc instead of ldc_w 1766 // unless we are trying to stress ldc -> ldc_w rewriting 1767 log_trace(redefine, class, constantpool) 1768 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index); 1769 *(bcp + 1) = new_index; 1770 } else { 1771 log_trace(redefine, class, constantpool) 1772 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index); 1773 // the new value needs ldc_w instead of ldc 1774 u_char inst_buffer[4]; // max instruction size is 4 bytes 1775 bcp = (address)inst_buffer; 1776 // construct new instruction sequence 1777 *bcp = Bytecodes::_ldc_w; 1778 bcp++; 1779 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w. 1780 // See comment below for difference between put_Java_u2() 1781 // and put_native_u2(). 1782 Bytes::put_Java_u2(bcp, new_index); 1783 1784 Relocator rc(method, NULL /* no RelocatorListener needed */); 1785 methodHandle m; 1786 { 1787 PauseNoSafepointVerifier pnsv(&nsv); 1788 1789 // ldc is 2 bytes and ldc_w is 3 bytes 1790 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK); 1791 } 1792 1793 // return the new method so that the caller can update 1794 // the containing class 1795 *new_method_p = method = m; 1796 // switch our bytecode processing loop from the old method 1797 // to the new method 1798 code_base = method->code_base(); 1799 code_length = method->code_size(); 1800 bcp = code_base + bci; 1801 c = (Bytecodes::Code)(*bcp); 1802 bc_length = Bytecodes::length_for(c); 1803 assert(bc_length != 0, "sanity check"); 1804 } // end we need ldc_w instead of ldc 1805 } // end if there is a mapped index 1806 } break; 1807 1808 // these bytecodes have a two-byte constant pool index 1809 case Bytecodes::_anewarray : // fall through 1810 case Bytecodes::_checkcast : // fall through 1811 case Bytecodes::_getfield : // fall through 1812 case Bytecodes::_getstatic : // fall through 1813 case Bytecodes::_instanceof : // fall through 1814 case Bytecodes::_invokedynamic : // fall through 1815 case Bytecodes::_invokeinterface: // fall through 1816 case Bytecodes::_invokespecial : // fall through 1817 case Bytecodes::_invokestatic : // fall through 1818 case Bytecodes::_invokevirtual : // fall through 1819 case Bytecodes::_ldc_w : // fall through 1820 case Bytecodes::_ldc2_w : // fall through 1821 case Bytecodes::_multianewarray : // fall through 1822 case Bytecodes::_new : // fall through 1823 case Bytecodes::_putfield : // fall through 1824 case Bytecodes::_putstatic : 1825 { 1826 address p = bcp + 1; 1827 int cp_index = Bytes::get_Java_u2(p); 1828 int new_index = find_new_index(cp_index); 1829 if (new_index != 0) { 1830 // the original index is mapped so update w/ new value 1831 log_trace(redefine, class, constantpool) 1832 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),p2i(bcp), cp_index, new_index); 1833 // Rewriter::rewrite_method() uses put_native_u2() in this 1834 // situation because it is reusing the constant pool index 1835 // location for a native index into the ConstantPoolCache. 1836 // Since we are updating the constant pool index prior to 1837 // verification and ConstantPoolCache initialization, we 1838 // need to keep the new index in Java byte order. 1839 Bytes::put_Java_u2(p, new_index); 1840 } 1841 } break; 1842 default: 1843 break; 1844 } 1845 } // end for each bytecode 1846 1847 // We also need to rewrite the parameter name indexes, if there is 1848 // method parameter data present 1849 if(method->has_method_parameters()) { 1850 const int len = method->method_parameters_length(); 1851 MethodParametersElement* elem = method->method_parameters_start(); 1852 1853 for (int i = 0; i < len; i++) { 1854 const u2 cp_index = elem[i].name_cp_index; 1855 const u2 new_cp_index = find_new_index(cp_index); 1856 if (new_cp_index != 0) { 1857 elem[i].name_cp_index = new_cp_index; 1858 } 1859 } 1860 } 1861 } // end rewrite_cp_refs_in_method() 1862 1863 1864 // Rewrite constant pool references in the class_annotations field. 1865 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations( 1866 InstanceKlass* scratch_class, TRAPS) { 1867 1868 AnnotationArray* class_annotations = scratch_class->class_annotations(); 1869 if (class_annotations == NULL || class_annotations->length() == 0) { 1870 // no class_annotations so nothing to do 1871 return true; 1872 } 1873 1874 log_debug(redefine, class, annotation)("class_annotations length=%d", class_annotations->length()); 1875 1876 int byte_i = 0; // byte index into class_annotations 1877 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i, 1878 THREAD); 1879 } 1880 1881 1882 // Rewrite constant pool references in an annotations typeArray. This 1883 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute 1884 // that is described in section 4.8.15 of the 2nd-edition of the VM spec: 1885 // 1886 // annotations_typeArray { 1887 // u2 num_annotations; 1888 // annotation annotations[num_annotations]; 1889 // } 1890 // 1891 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray( 1892 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) { 1893 1894 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 1895 // not enough room for num_annotations field 1896 log_debug(redefine, class, annotation)("length() is too small for num_annotations field"); 1897 return false; 1898 } 1899 1900 u2 num_annotations = Bytes::get_Java_u2((address) 1901 annotations_typeArray->adr_at(byte_i_ref)); 1902 byte_i_ref += 2; 1903 1904 log_debug(redefine, class, annotation)("num_annotations=%d", num_annotations); 1905 1906 int calc_num_annotations = 0; 1907 for (; calc_num_annotations < num_annotations; calc_num_annotations++) { 1908 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, 1909 byte_i_ref, THREAD)) { 1910 log_debug(redefine, class, annotation)("bad annotation_struct at %d", calc_num_annotations); 1911 // propagate failure back to caller 1912 return false; 1913 } 1914 } 1915 assert(num_annotations == calc_num_annotations, "sanity check"); 1916 1917 return true; 1918 } // end rewrite_cp_refs_in_annotations_typeArray() 1919 1920 1921 // Rewrite constant pool references in the annotation struct portion of 1922 // an annotations_typeArray. This "structure" is from section 4.8.15 of 1923 // the 2nd-edition of the VM spec: 1924 // 1925 // struct annotation { 1926 // u2 type_index; 1927 // u2 num_element_value_pairs; 1928 // { 1929 // u2 element_name_index; 1930 // element_value value; 1931 // } element_value_pairs[num_element_value_pairs]; 1932 // } 1933 // 1934 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct( 1935 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) { 1936 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) { 1937 // not enough room for smallest annotation_struct 1938 log_debug(redefine, class, annotation)("length() is too small for annotation_struct"); 1939 return false; 1940 } 1941 1942 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray, 1943 byte_i_ref, "type_index", THREAD); 1944 1945 u2 num_element_value_pairs = Bytes::get_Java_u2((address) 1946 annotations_typeArray->adr_at(byte_i_ref)); 1947 byte_i_ref += 2; 1948 1949 log_debug(redefine, class, annotation) 1950 ("type_index=%d num_element_value_pairs=%d", type_index, num_element_value_pairs); 1951 1952 int calc_num_element_value_pairs = 0; 1953 for (; calc_num_element_value_pairs < num_element_value_pairs; 1954 calc_num_element_value_pairs++) { 1955 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 1956 // not enough room for another element_name_index, let alone 1957 // the rest of another component 1958 log_debug(redefine, class, annotation)("length() is too small for element_name_index"); 1959 return false; 1960 } 1961 1962 u2 element_name_index = rewrite_cp_ref_in_annotation_data( 1963 annotations_typeArray, byte_i_ref, 1964 "element_name_index", THREAD); 1965 1966 log_debug(redefine, class, annotation)("element_name_index=%d", element_name_index); 1967 1968 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, 1969 byte_i_ref, THREAD)) { 1970 log_debug(redefine, class, annotation)("bad element_value at %d", calc_num_element_value_pairs); 1971 // propagate failure back to caller 1972 return false; 1973 } 1974 } // end for each component 1975 assert(num_element_value_pairs == calc_num_element_value_pairs, 1976 "sanity check"); 1977 1978 return true; 1979 } // end rewrite_cp_refs_in_annotation_struct() 1980 1981 1982 // Rewrite a constant pool reference at the current position in 1983 // annotations_typeArray if needed. Returns the original constant 1984 // pool reference if a rewrite was not needed or the new constant 1985 // pool reference if a rewrite was needed. 1986 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data( 1987 AnnotationArray* annotations_typeArray, int &byte_i_ref, 1988 const char * trace_mesg, TRAPS) { 1989 1990 address cp_index_addr = (address) 1991 annotations_typeArray->adr_at(byte_i_ref); 1992 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr); 1993 u2 new_cp_index = find_new_index(old_cp_index); 1994 if (new_cp_index != 0) { 1995 log_debug(redefine, class, annotation)("mapped old %s=%d", trace_mesg, old_cp_index); 1996 Bytes::put_Java_u2(cp_index_addr, new_cp_index); 1997 old_cp_index = new_cp_index; 1998 } 1999 byte_i_ref += 2; 2000 return old_cp_index; 2001 } 2002 2003 2004 // Rewrite constant pool references in the element_value portion of an 2005 // annotations_typeArray. This "structure" is from section 4.8.15.1 of 2006 // the 2nd-edition of the VM spec: 2007 // 2008 // struct element_value { 2009 // u1 tag; 2010 // union { 2011 // u2 const_value_index; 2012 // { 2013 // u2 type_name_index; 2014 // u2 const_name_index; 2015 // } enum_const_value; 2016 // u2 class_info_index; 2017 // annotation annotation_value; 2018 // struct { 2019 // u2 num_values; 2020 // element_value values[num_values]; 2021 // } array_value; 2022 // } value; 2023 // } 2024 // 2025 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value( 2026 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) { 2027 2028 if ((byte_i_ref + 1) > annotations_typeArray->length()) { 2029 // not enough room for a tag let alone the rest of an element_value 2030 log_debug(redefine, class, annotation)("length() is too small for a tag"); 2031 return false; 2032 } 2033 2034 u1 tag = annotations_typeArray->at(byte_i_ref); 2035 byte_i_ref++; 2036 log_debug(redefine, class, annotation)("tag='%c'", tag); 2037 2038 switch (tag) { 2039 // These BaseType tag values are from Table 4.2 in VM spec: 2040 case 'B': // byte 2041 case 'C': // char 2042 case 'D': // double 2043 case 'F': // float 2044 case 'I': // int 2045 case 'J': // long 2046 case 'S': // short 2047 case 'Z': // boolean 2048 2049 // The remaining tag values are from Table 4.8 in the 2nd-edition of 2050 // the VM spec: 2051 case 's': 2052 { 2053 // For the above tag values (including the BaseType values), 2054 // value.const_value_index is right union field. 2055 2056 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2057 // not enough room for a const_value_index 2058 log_debug(redefine, class, annotation)("length() is too small for a const_value_index"); 2059 return false; 2060 } 2061 2062 u2 const_value_index = rewrite_cp_ref_in_annotation_data( 2063 annotations_typeArray, byte_i_ref, 2064 "const_value_index", THREAD); 2065 2066 log_debug(redefine, class, annotation)("const_value_index=%d", const_value_index); 2067 } break; 2068 2069 case 'e': 2070 { 2071 // for the above tag value, value.enum_const_value is right union field 2072 2073 if ((byte_i_ref + 4) > annotations_typeArray->length()) { 2074 // not enough room for a enum_const_value 2075 log_debug(redefine, class, annotation)("length() is too small for a enum_const_value"); 2076 return false; 2077 } 2078 2079 u2 type_name_index = rewrite_cp_ref_in_annotation_data( 2080 annotations_typeArray, byte_i_ref, 2081 "type_name_index", THREAD); 2082 2083 u2 const_name_index = rewrite_cp_ref_in_annotation_data( 2084 annotations_typeArray, byte_i_ref, 2085 "const_name_index", THREAD); 2086 2087 log_debug(redefine, class, annotation) 2088 ("type_name_index=%d const_name_index=%d", type_name_index, const_name_index); 2089 } break; 2090 2091 case 'c': 2092 { 2093 // for the above tag value, value.class_info_index is right union field 2094 2095 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2096 // not enough room for a class_info_index 2097 log_debug(redefine, class, annotation)("length() is too small for a class_info_index"); 2098 return false; 2099 } 2100 2101 u2 class_info_index = rewrite_cp_ref_in_annotation_data( 2102 annotations_typeArray, byte_i_ref, 2103 "class_info_index", THREAD); 2104 2105 log_debug(redefine, class, annotation)("class_info_index=%d", class_info_index); 2106 } break; 2107 2108 case '@': 2109 // For the above tag value, value.attr_value is the right union 2110 // field. This is a nested annotation. 2111 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, 2112 byte_i_ref, THREAD)) { 2113 // propagate failure back to caller 2114 return false; 2115 } 2116 break; 2117 2118 case '[': 2119 { 2120 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2121 // not enough room for a num_values field 2122 log_debug(redefine, class, annotation)("length() is too small for a num_values field"); 2123 return false; 2124 } 2125 2126 // For the above tag value, value.array_value is the right union 2127 // field. This is an array of nested element_value. 2128 u2 num_values = Bytes::get_Java_u2((address) 2129 annotations_typeArray->adr_at(byte_i_ref)); 2130 byte_i_ref += 2; 2131 log_debug(redefine, class, annotation)("num_values=%d", num_values); 2132 2133 int calc_num_values = 0; 2134 for (; calc_num_values < num_values; calc_num_values++) { 2135 if (!rewrite_cp_refs_in_element_value( 2136 annotations_typeArray, byte_i_ref, THREAD)) { 2137 log_debug(redefine, class, annotation)("bad nested element_value at %d", calc_num_values); 2138 // propagate failure back to caller 2139 return false; 2140 } 2141 } 2142 assert(num_values == calc_num_values, "sanity check"); 2143 } break; 2144 2145 default: 2146 log_debug(redefine, class, annotation)("bad tag=0x%x", tag); 2147 return false; 2148 } // end decode tag field 2149 2150 return true; 2151 } // end rewrite_cp_refs_in_element_value() 2152 2153 2154 // Rewrite constant pool references in a fields_annotations field. 2155 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations( 2156 InstanceKlass* scratch_class, TRAPS) { 2157 2158 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations(); 2159 2160 if (fields_annotations == NULL || fields_annotations->length() == 0) { 2161 // no fields_annotations so nothing to do 2162 return true; 2163 } 2164 2165 log_debug(redefine, class, annotation)("fields_annotations length=%d", fields_annotations->length()); 2166 2167 for (int i = 0; i < fields_annotations->length(); i++) { 2168 AnnotationArray* field_annotations = fields_annotations->at(i); 2169 if (field_annotations == NULL || field_annotations->length() == 0) { 2170 // this field does not have any annotations so skip it 2171 continue; 2172 } 2173 2174 int byte_i = 0; // byte index into field_annotations 2175 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i, 2176 THREAD)) { 2177 log_debug(redefine, class, annotation)("bad field_annotations at %d", i); 2178 // propagate failure back to caller 2179 return false; 2180 } 2181 } 2182 2183 return true; 2184 } // end rewrite_cp_refs_in_fields_annotations() 2185 2186 2187 // Rewrite constant pool references in a methods_annotations field. 2188 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations( 2189 InstanceKlass* scratch_class, TRAPS) { 2190 2191 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2192 Method* m = scratch_class->methods()->at(i); 2193 AnnotationArray* method_annotations = m->constMethod()->method_annotations(); 2194 2195 if (method_annotations == NULL || method_annotations->length() == 0) { 2196 // this method does not have any annotations so skip it 2197 continue; 2198 } 2199 2200 int byte_i = 0; // byte index into method_annotations 2201 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i, 2202 THREAD)) { 2203 log_debug(redefine, class, annotation)("bad method_annotations at %d", i); 2204 // propagate failure back to caller 2205 return false; 2206 } 2207 } 2208 2209 return true; 2210 } // end rewrite_cp_refs_in_methods_annotations() 2211 2212 2213 // Rewrite constant pool references in a methods_parameter_annotations 2214 // field. This "structure" is adapted from the 2215 // RuntimeVisibleParameterAnnotations_attribute described in section 2216 // 4.8.17 of the 2nd-edition of the VM spec: 2217 // 2218 // methods_parameter_annotations_typeArray { 2219 // u1 num_parameters; 2220 // { 2221 // u2 num_annotations; 2222 // annotation annotations[num_annotations]; 2223 // } parameter_annotations[num_parameters]; 2224 // } 2225 // 2226 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations( 2227 InstanceKlass* scratch_class, TRAPS) { 2228 2229 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2230 Method* m = scratch_class->methods()->at(i); 2231 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations(); 2232 if (method_parameter_annotations == NULL 2233 || method_parameter_annotations->length() == 0) { 2234 // this method does not have any parameter annotations so skip it 2235 continue; 2236 } 2237 2238 if (method_parameter_annotations->length() < 1) { 2239 // not enough room for a num_parameters field 2240 log_debug(redefine, class, annotation)("length() is too small for a num_parameters field at %d", i); 2241 return false; 2242 } 2243 2244 int byte_i = 0; // byte index into method_parameter_annotations 2245 2246 u1 num_parameters = method_parameter_annotations->at(byte_i); 2247 byte_i++; 2248 2249 log_debug(redefine, class, annotation)("num_parameters=%d", num_parameters); 2250 2251 int calc_num_parameters = 0; 2252 for (; calc_num_parameters < num_parameters; calc_num_parameters++) { 2253 if (!rewrite_cp_refs_in_annotations_typeArray( 2254 method_parameter_annotations, byte_i, THREAD)) { 2255 log_debug(redefine, class, annotation)("bad method_parameter_annotations at %d", calc_num_parameters); 2256 // propagate failure back to caller 2257 return false; 2258 } 2259 } 2260 assert(num_parameters == calc_num_parameters, "sanity check"); 2261 } 2262 2263 return true; 2264 } // end rewrite_cp_refs_in_methods_parameter_annotations() 2265 2266 2267 // Rewrite constant pool references in a methods_default_annotations 2268 // field. This "structure" is adapted from the AnnotationDefault_attribute 2269 // that is described in section 4.8.19 of the 2nd-edition of the VM spec: 2270 // 2271 // methods_default_annotations_typeArray { 2272 // element_value default_value; 2273 // } 2274 // 2275 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations( 2276 InstanceKlass* scratch_class, TRAPS) { 2277 2278 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2279 Method* m = scratch_class->methods()->at(i); 2280 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations(); 2281 if (method_default_annotations == NULL 2282 || method_default_annotations->length() == 0) { 2283 // this method does not have any default annotations so skip it 2284 continue; 2285 } 2286 2287 int byte_i = 0; // byte index into method_default_annotations 2288 2289 if (!rewrite_cp_refs_in_element_value( 2290 method_default_annotations, byte_i, THREAD)) { 2291 log_debug(redefine, class, annotation)("bad default element_value at %d", i); 2292 // propagate failure back to caller 2293 return false; 2294 } 2295 } 2296 2297 return true; 2298 } // end rewrite_cp_refs_in_methods_default_annotations() 2299 2300 2301 // Rewrite constant pool references in a class_type_annotations field. 2302 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations( 2303 InstanceKlass* scratch_class, TRAPS) { 2304 2305 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations(); 2306 if (class_type_annotations == NULL || class_type_annotations->length() == 0) { 2307 // no class_type_annotations so nothing to do 2308 return true; 2309 } 2310 2311 log_debug(redefine, class, annotation)("class_type_annotations length=%d", class_type_annotations->length()); 2312 2313 int byte_i = 0; // byte index into class_type_annotations 2314 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations, 2315 byte_i, "ClassFile", THREAD); 2316 } // end rewrite_cp_refs_in_class_type_annotations() 2317 2318 2319 // Rewrite constant pool references in a fields_type_annotations field. 2320 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations( 2321 InstanceKlass* scratch_class, TRAPS) { 2322 2323 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations(); 2324 if (fields_type_annotations == NULL || fields_type_annotations->length() == 0) { 2325 // no fields_type_annotations so nothing to do 2326 return true; 2327 } 2328 2329 log_debug(redefine, class, annotation)("fields_type_annotations length=%d", fields_type_annotations->length()); 2330 2331 for (int i = 0; i < fields_type_annotations->length(); i++) { 2332 AnnotationArray* field_type_annotations = fields_type_annotations->at(i); 2333 if (field_type_annotations == NULL || field_type_annotations->length() == 0) { 2334 // this field does not have any annotations so skip it 2335 continue; 2336 } 2337 2338 int byte_i = 0; // byte index into field_type_annotations 2339 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations, 2340 byte_i, "field_info", THREAD)) { 2341 log_debug(redefine, class, annotation)("bad field_type_annotations at %d", i); 2342 // propagate failure back to caller 2343 return false; 2344 } 2345 } 2346 2347 return true; 2348 } // end rewrite_cp_refs_in_fields_type_annotations() 2349 2350 2351 // Rewrite constant pool references in a methods_type_annotations field. 2352 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations( 2353 InstanceKlass* scratch_class, TRAPS) { 2354 2355 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2356 Method* m = scratch_class->methods()->at(i); 2357 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations(); 2358 2359 if (method_type_annotations == NULL || method_type_annotations->length() == 0) { 2360 // this method does not have any annotations so skip it 2361 continue; 2362 } 2363 2364 log_debug(redefine, class, annotation)("methods type_annotations length=%d", method_type_annotations->length()); 2365 2366 int byte_i = 0; // byte index into method_type_annotations 2367 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations, 2368 byte_i, "method_info", THREAD)) { 2369 log_debug(redefine, class, annotation)("bad method_type_annotations at %d", i); 2370 // propagate failure back to caller 2371 return false; 2372 } 2373 } 2374 2375 return true; 2376 } // end rewrite_cp_refs_in_methods_type_annotations() 2377 2378 2379 // Rewrite constant pool references in a type_annotations 2380 // field. This "structure" is adapted from the 2381 // RuntimeVisibleTypeAnnotations_attribute described in 2382 // section 4.7.20 of the Java SE 8 Edition of the VM spec: 2383 // 2384 // type_annotations_typeArray { 2385 // u2 num_annotations; 2386 // type_annotation annotations[num_annotations]; 2387 // } 2388 // 2389 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray( 2390 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2391 const char * location_mesg, TRAPS) { 2392 2393 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2394 // not enough room for num_annotations field 2395 log_debug(redefine, class, annotation)("length() is too small for num_annotations field"); 2396 return false; 2397 } 2398 2399 u2 num_annotations = Bytes::get_Java_u2((address) 2400 type_annotations_typeArray->adr_at(byte_i_ref)); 2401 byte_i_ref += 2; 2402 2403 log_debug(redefine, class, annotation)("num_type_annotations=%d", num_annotations); 2404 2405 int calc_num_annotations = 0; 2406 for (; calc_num_annotations < num_annotations; calc_num_annotations++) { 2407 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray, 2408 byte_i_ref, location_mesg, THREAD)) { 2409 log_debug(redefine, class, annotation)("bad type_annotation_struct at %d", calc_num_annotations); 2410 // propagate failure back to caller 2411 return false; 2412 } 2413 } 2414 assert(num_annotations == calc_num_annotations, "sanity check"); 2415 2416 if (byte_i_ref != type_annotations_typeArray->length()) { 2417 log_debug(redefine, class, annotation) 2418 ("read wrong amount of bytes at end of processing type_annotations_typeArray (%d of %d bytes were read)", 2419 byte_i_ref, type_annotations_typeArray->length()); 2420 return false; 2421 } 2422 2423 return true; 2424 } // end rewrite_cp_refs_in_type_annotations_typeArray() 2425 2426 2427 // Rewrite constant pool references in a type_annotation 2428 // field. This "structure" is adapted from the 2429 // RuntimeVisibleTypeAnnotations_attribute described in 2430 // section 4.7.20 of the Java SE 8 Edition of the VM spec: 2431 // 2432 // type_annotation { 2433 // u1 target_type; 2434 // union { 2435 // type_parameter_target; 2436 // supertype_target; 2437 // type_parameter_bound_target; 2438 // empty_target; 2439 // method_formal_parameter_target; 2440 // throws_target; 2441 // localvar_target; 2442 // catch_target; 2443 // offset_target; 2444 // type_argument_target; 2445 // } target_info; 2446 // type_path target_path; 2447 // annotation anno; 2448 // } 2449 // 2450 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct( 2451 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2452 const char * location_mesg, TRAPS) { 2453 2454 if (!skip_type_annotation_target(type_annotations_typeArray, 2455 byte_i_ref, location_mesg, THREAD)) { 2456 return false; 2457 } 2458 2459 if (!skip_type_annotation_type_path(type_annotations_typeArray, 2460 byte_i_ref, THREAD)) { 2461 return false; 2462 } 2463 2464 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray, 2465 byte_i_ref, THREAD)) { 2466 return false; 2467 } 2468 2469 return true; 2470 } // end rewrite_cp_refs_in_type_annotation_struct() 2471 2472 2473 // Read, verify and skip over the target_type and target_info part 2474 // so that rewriting can continue in the later parts of the struct. 2475 // 2476 // u1 target_type; 2477 // union { 2478 // type_parameter_target; 2479 // supertype_target; 2480 // type_parameter_bound_target; 2481 // empty_target; 2482 // method_formal_parameter_target; 2483 // throws_target; 2484 // localvar_target; 2485 // catch_target; 2486 // offset_target; 2487 // type_argument_target; 2488 // } target_info; 2489 // 2490 bool VM_RedefineClasses::skip_type_annotation_target( 2491 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2492 const char * location_mesg, TRAPS) { 2493 2494 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2495 // not enough room for a target_type let alone the rest of a type_annotation 2496 log_debug(redefine, class, annotation)("length() is too small for a target_type"); 2497 return false; 2498 } 2499 2500 u1 target_type = type_annotations_typeArray->at(byte_i_ref); 2501 byte_i_ref += 1; 2502 log_debug(redefine, class, annotation)("target_type=0x%.2x", target_type); 2503 log_debug(redefine, class, annotation)("location=%s", location_mesg); 2504 2505 // Skip over target_info 2506 switch (target_type) { 2507 case 0x00: 2508 // kind: type parameter declaration of generic class or interface 2509 // location: ClassFile 2510 case 0x01: 2511 // kind: type parameter declaration of generic method or constructor 2512 // location: method_info 2513 2514 { 2515 // struct: 2516 // type_parameter_target { 2517 // u1 type_parameter_index; 2518 // } 2519 // 2520 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2521 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_target"); 2522 return false; 2523 } 2524 2525 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2526 byte_i_ref += 1; 2527 2528 log_debug(redefine, class, annotation)("type_parameter_target: type_parameter_index=%d", type_parameter_index); 2529 } break; 2530 2531 case 0x10: 2532 // kind: type in extends clause of class or interface declaration 2533 // (including the direct superclass of an anonymous class declaration), 2534 // or in implements clause of interface declaration 2535 // location: ClassFile 2536 2537 { 2538 // struct: 2539 // supertype_target { 2540 // u2 supertype_index; 2541 // } 2542 // 2543 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2544 log_debug(redefine, class, annotation)("length() is too small for a supertype_target"); 2545 return false; 2546 } 2547 2548 u2 supertype_index = Bytes::get_Java_u2((address) 2549 type_annotations_typeArray->adr_at(byte_i_ref)); 2550 byte_i_ref += 2; 2551 2552 log_debug(redefine, class, annotation)("supertype_target: supertype_index=%d", supertype_index); 2553 } break; 2554 2555 case 0x11: 2556 // kind: type in bound of type parameter declaration of generic class or interface 2557 // location: ClassFile 2558 case 0x12: 2559 // kind: type in bound of type parameter declaration of generic method or constructor 2560 // location: method_info 2561 2562 { 2563 // struct: 2564 // type_parameter_bound_target { 2565 // u1 type_parameter_index; 2566 // u1 bound_index; 2567 // } 2568 // 2569 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2570 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_bound_target"); 2571 return false; 2572 } 2573 2574 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2575 byte_i_ref += 1; 2576 u1 bound_index = type_annotations_typeArray->at(byte_i_ref); 2577 byte_i_ref += 1; 2578 2579 log_debug(redefine, class, annotation) 2580 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d", type_parameter_index, bound_index); 2581 } break; 2582 2583 case 0x13: 2584 // kind: type in field declaration 2585 // location: field_info 2586 case 0x14: 2587 // kind: return type of method, or type of newly constructed object 2588 // location: method_info 2589 case 0x15: 2590 // kind: receiver type of method or constructor 2591 // location: method_info 2592 2593 { 2594 // struct: 2595 // empty_target { 2596 // } 2597 // 2598 log_debug(redefine, class, annotation)("empty_target"); 2599 } break; 2600 2601 case 0x16: 2602 // kind: type in formal parameter declaration of method, constructor, or lambda expression 2603 // location: method_info 2604 2605 { 2606 // struct: 2607 // formal_parameter_target { 2608 // u1 formal_parameter_index; 2609 // } 2610 // 2611 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2612 log_debug(redefine, class, annotation)("length() is too small for a formal_parameter_target"); 2613 return false; 2614 } 2615 2616 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2617 byte_i_ref += 1; 2618 2619 log_debug(redefine, class, annotation) 2620 ("formal_parameter_target: formal_parameter_index=%d", formal_parameter_index); 2621 } break; 2622 2623 case 0x17: 2624 // kind: type in throws clause of method or constructor 2625 // location: method_info 2626 2627 { 2628 // struct: 2629 // throws_target { 2630 // u2 throws_type_index 2631 // } 2632 // 2633 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2634 log_debug(redefine, class, annotation)("length() is too small for a throws_target"); 2635 return false; 2636 } 2637 2638 u2 throws_type_index = Bytes::get_Java_u2((address) 2639 type_annotations_typeArray->adr_at(byte_i_ref)); 2640 byte_i_ref += 2; 2641 2642 log_debug(redefine, class, annotation)("throws_target: throws_type_index=%d", throws_type_index); 2643 } break; 2644 2645 case 0x40: 2646 // kind: type in local variable declaration 2647 // location: Code 2648 case 0x41: 2649 // kind: type in resource variable declaration 2650 // location: Code 2651 2652 { 2653 // struct: 2654 // localvar_target { 2655 // u2 table_length; 2656 // struct { 2657 // u2 start_pc; 2658 // u2 length; 2659 // u2 index; 2660 // } table[table_length]; 2661 // } 2662 // 2663 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2664 // not enough room for a table_length let alone the rest of a localvar_target 2665 log_debug(redefine, class, annotation)("length() is too small for a localvar_target table_length"); 2666 return false; 2667 } 2668 2669 u2 table_length = Bytes::get_Java_u2((address) 2670 type_annotations_typeArray->adr_at(byte_i_ref)); 2671 byte_i_ref += 2; 2672 2673 log_debug(redefine, class, annotation)("localvar_target: table_length=%d", table_length); 2674 2675 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry 2676 int table_size = table_length * table_struct_size; 2677 2678 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) { 2679 // not enough room for a table 2680 log_debug(redefine, class, annotation)("length() is too small for a table array of length %d", table_length); 2681 return false; 2682 } 2683 2684 // Skip over table 2685 byte_i_ref += table_size; 2686 } break; 2687 2688 case 0x42: 2689 // kind: type in exception parameter declaration 2690 // location: Code 2691 2692 { 2693 // struct: 2694 // catch_target { 2695 // u2 exception_table_index; 2696 // } 2697 // 2698 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2699 log_debug(redefine, class, annotation)("length() is too small for a catch_target"); 2700 return false; 2701 } 2702 2703 u2 exception_table_index = Bytes::get_Java_u2((address) 2704 type_annotations_typeArray->adr_at(byte_i_ref)); 2705 byte_i_ref += 2; 2706 2707 log_debug(redefine, class, annotation)("catch_target: exception_table_index=%d", exception_table_index); 2708 } break; 2709 2710 case 0x43: 2711 // kind: type in instanceof expression 2712 // location: Code 2713 case 0x44: 2714 // kind: type in new expression 2715 // location: Code 2716 case 0x45: 2717 // kind: type in method reference expression using ::new 2718 // location: Code 2719 case 0x46: 2720 // kind: type in method reference expression using ::Identifier 2721 // location: Code 2722 2723 { 2724 // struct: 2725 // offset_target { 2726 // u2 offset; 2727 // } 2728 // 2729 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2730 log_debug(redefine, class, annotation)("length() is too small for a offset_target"); 2731 return false; 2732 } 2733 2734 u2 offset = Bytes::get_Java_u2((address) 2735 type_annotations_typeArray->adr_at(byte_i_ref)); 2736 byte_i_ref += 2; 2737 2738 log_debug(redefine, class, annotation)("offset_target: offset=%d", offset); 2739 } break; 2740 2741 case 0x47: 2742 // kind: type in cast expression 2743 // location: Code 2744 case 0x48: 2745 // kind: type argument for generic constructor in new expression or 2746 // explicit constructor invocation statement 2747 // location: Code 2748 case 0x49: 2749 // kind: type argument for generic method in method invocation expression 2750 // location: Code 2751 case 0x4A: 2752 // kind: type argument for generic constructor in method reference expression using ::new 2753 // location: Code 2754 case 0x4B: 2755 // kind: type argument for generic method in method reference expression using ::Identifier 2756 // location: Code 2757 2758 { 2759 // struct: 2760 // type_argument_target { 2761 // u2 offset; 2762 // u1 type_argument_index; 2763 // } 2764 // 2765 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) { 2766 log_debug(redefine, class, annotation)("length() is too small for a type_argument_target"); 2767 return false; 2768 } 2769 2770 u2 offset = Bytes::get_Java_u2((address) 2771 type_annotations_typeArray->adr_at(byte_i_ref)); 2772 byte_i_ref += 2; 2773 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref); 2774 byte_i_ref += 1; 2775 2776 log_debug(redefine, class, annotation) 2777 ("type_argument_target: offset=%d, type_argument_index=%d", offset, type_argument_index); 2778 } break; 2779 2780 default: 2781 log_debug(redefine, class, annotation)("unknown target_type"); 2782 #ifdef ASSERT 2783 ShouldNotReachHere(); 2784 #endif 2785 return false; 2786 } 2787 2788 return true; 2789 } // end skip_type_annotation_target() 2790 2791 2792 // Read, verify and skip over the type_path part so that rewriting 2793 // can continue in the later parts of the struct. 2794 // 2795 // type_path { 2796 // u1 path_length; 2797 // { 2798 // u1 type_path_kind; 2799 // u1 type_argument_index; 2800 // } path[path_length]; 2801 // } 2802 // 2803 bool VM_RedefineClasses::skip_type_annotation_type_path( 2804 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, TRAPS) { 2805 2806 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2807 // not enough room for a path_length let alone the rest of the type_path 2808 log_debug(redefine, class, annotation)("length() is too small for a type_path"); 2809 return false; 2810 } 2811 2812 u1 path_length = type_annotations_typeArray->at(byte_i_ref); 2813 byte_i_ref += 1; 2814 2815 log_debug(redefine, class, annotation)("type_path: path_length=%d", path_length); 2816 2817 int calc_path_length = 0; 2818 for (; calc_path_length < path_length; calc_path_length++) { 2819 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) { 2820 // not enough room for a path 2821 log_debug(redefine, class, annotation) 2822 ("length() is too small for path entry %d of %d", calc_path_length, path_length); 2823 return false; 2824 } 2825 2826 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref); 2827 byte_i_ref += 1; 2828 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref); 2829 byte_i_ref += 1; 2830 2831 log_debug(redefine, class, annotation) 2832 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d", 2833 calc_path_length, type_path_kind, type_argument_index); 2834 2835 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) { 2836 // not enough room for a path 2837 log_debug(redefine, class, annotation)("inconsistent type_path values"); 2838 return false; 2839 } 2840 } 2841 assert(path_length == calc_path_length, "sanity check"); 2842 2843 return true; 2844 } // end skip_type_annotation_type_path() 2845 2846 2847 // Rewrite constant pool references in the method's stackmap table. 2848 // These "structures" are adapted from the StackMapTable_attribute that 2849 // is described in section 4.8.4 of the 6.0 version of the VM spec 2850 // (dated 2005.10.26): 2851 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf 2852 // 2853 // stack_map { 2854 // u2 number_of_entries; 2855 // stack_map_frame entries[number_of_entries]; 2856 // } 2857 // 2858 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table( 2859 const methodHandle& method, TRAPS) { 2860 2861 if (!method->has_stackmap_table()) { 2862 return; 2863 } 2864 2865 AnnotationArray* stackmap_data = method->stackmap_data(); 2866 address stackmap_p = (address)stackmap_data->adr_at(0); 2867 address stackmap_end = stackmap_p + stackmap_data->length(); 2868 2869 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries"); 2870 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p); 2871 stackmap_p += 2; 2872 2873 log_debug(redefine, class, stackmap)("number_of_entries=%u", number_of_entries); 2874 2875 // walk through each stack_map_frame 2876 u2 calc_number_of_entries = 0; 2877 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) { 2878 // The stack_map_frame structure is a u1 frame_type followed by 2879 // 0 or more bytes of data: 2880 // 2881 // union stack_map_frame { 2882 // same_frame; 2883 // same_locals_1_stack_item_frame; 2884 // same_locals_1_stack_item_frame_extended; 2885 // chop_frame; 2886 // same_frame_extended; 2887 // append_frame; 2888 // full_frame; 2889 // } 2890 2891 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type"); 2892 u1 frame_type = *stackmap_p; 2893 stackmap_p++; 2894 2895 // same_frame { 2896 // u1 frame_type = SAME; /* 0-63 */ 2897 // } 2898 if (frame_type <= 63) { 2899 // nothing more to do for same_frame 2900 } 2901 2902 // same_locals_1_stack_item_frame { 2903 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */ 2904 // verification_type_info stack[1]; 2905 // } 2906 else if (frame_type >= 64 && frame_type <= 127) { 2907 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2908 calc_number_of_entries, frame_type, THREAD); 2909 } 2910 2911 // reserved for future use 2912 else if (frame_type >= 128 && frame_type <= 246) { 2913 // nothing more to do for reserved frame_types 2914 } 2915 2916 // same_locals_1_stack_item_frame_extended { 2917 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */ 2918 // u2 offset_delta; 2919 // verification_type_info stack[1]; 2920 // } 2921 else if (frame_type == 247) { 2922 stackmap_p += 2; 2923 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2924 calc_number_of_entries, frame_type, THREAD); 2925 } 2926 2927 // chop_frame { 2928 // u1 frame_type = CHOP; /* 248-250 */ 2929 // u2 offset_delta; 2930 // } 2931 else if (frame_type >= 248 && frame_type <= 250) { 2932 stackmap_p += 2; 2933 } 2934 2935 // same_frame_extended { 2936 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/ 2937 // u2 offset_delta; 2938 // } 2939 else if (frame_type == 251) { 2940 stackmap_p += 2; 2941 } 2942 2943 // append_frame { 2944 // u1 frame_type = APPEND; /* 252-254 */ 2945 // u2 offset_delta; 2946 // verification_type_info locals[frame_type - 251]; 2947 // } 2948 else if (frame_type >= 252 && frame_type <= 254) { 2949 assert(stackmap_p + 2 <= stackmap_end, 2950 "no room for offset_delta"); 2951 stackmap_p += 2; 2952 u1 len = frame_type - 251; 2953 for (u1 i = 0; i < len; i++) { 2954 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2955 calc_number_of_entries, frame_type, THREAD); 2956 } 2957 } 2958 2959 // full_frame { 2960 // u1 frame_type = FULL_FRAME; /* 255 */ 2961 // u2 offset_delta; 2962 // u2 number_of_locals; 2963 // verification_type_info locals[number_of_locals]; 2964 // u2 number_of_stack_items; 2965 // verification_type_info stack[number_of_stack_items]; 2966 // } 2967 else if (frame_type == 255) { 2968 assert(stackmap_p + 2 + 2 <= stackmap_end, 2969 "no room for smallest full_frame"); 2970 stackmap_p += 2; 2971 2972 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p); 2973 stackmap_p += 2; 2974 2975 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) { 2976 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2977 calc_number_of_entries, frame_type, THREAD); 2978 } 2979 2980 // Use the largest size for the number_of_stack_items, but only get 2981 // the right number of bytes. 2982 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p); 2983 stackmap_p += 2; 2984 2985 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) { 2986 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2987 calc_number_of_entries, frame_type, THREAD); 2988 } 2989 } 2990 } // end while there is a stack_map_frame 2991 assert(number_of_entries == calc_number_of_entries, "sanity check"); 2992 } // end rewrite_cp_refs_in_stack_map_table() 2993 2994 2995 // Rewrite constant pool references in the verification type info 2996 // portion of the method's stackmap table. These "structures" are 2997 // adapted from the StackMapTable_attribute that is described in 2998 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26): 2999 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf 3000 // 3001 // The verification_type_info structure is a u1 tag followed by 0 or 3002 // more bytes of data: 3003 // 3004 // union verification_type_info { 3005 // Top_variable_info; 3006 // Integer_variable_info; 3007 // Float_variable_info; 3008 // Long_variable_info; 3009 // Double_variable_info; 3010 // Null_variable_info; 3011 // UninitializedThis_variable_info; 3012 // Object_variable_info; 3013 // Uninitialized_variable_info; 3014 // } 3015 // 3016 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info( 3017 address& stackmap_p_ref, address stackmap_end, u2 frame_i, 3018 u1 frame_type, TRAPS) { 3019 3020 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag"); 3021 u1 tag = *stackmap_p_ref; 3022 stackmap_p_ref++; 3023 3024 switch (tag) { 3025 // Top_variable_info { 3026 // u1 tag = ITEM_Top; /* 0 */ 3027 // } 3028 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top 3029 case 0: // fall through 3030 3031 // Integer_variable_info { 3032 // u1 tag = ITEM_Integer; /* 1 */ 3033 // } 3034 case ITEM_Integer: // fall through 3035 3036 // Float_variable_info { 3037 // u1 tag = ITEM_Float; /* 2 */ 3038 // } 3039 case ITEM_Float: // fall through 3040 3041 // Double_variable_info { 3042 // u1 tag = ITEM_Double; /* 3 */ 3043 // } 3044 case ITEM_Double: // fall through 3045 3046 // Long_variable_info { 3047 // u1 tag = ITEM_Long; /* 4 */ 3048 // } 3049 case ITEM_Long: // fall through 3050 3051 // Null_variable_info { 3052 // u1 tag = ITEM_Null; /* 5 */ 3053 // } 3054 case ITEM_Null: // fall through 3055 3056 // UninitializedThis_variable_info { 3057 // u1 tag = ITEM_UninitializedThis; /* 6 */ 3058 // } 3059 case ITEM_UninitializedThis: 3060 // nothing more to do for the above tag types 3061 break; 3062 3063 // Object_variable_info { 3064 // u1 tag = ITEM_Object; /* 7 */ 3065 // u2 cpool_index; 3066 // } 3067 case ITEM_Object: 3068 { 3069 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index"); 3070 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref); 3071 u2 new_cp_index = find_new_index(cpool_index); 3072 if (new_cp_index != 0) { 3073 log_debug(redefine, class, stackmap)("mapped old cpool_index=%d", cpool_index); 3074 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index); 3075 cpool_index = new_cp_index; 3076 } 3077 stackmap_p_ref += 2; 3078 3079 log_debug(redefine, class, stackmap) 3080 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i, frame_type, cpool_index); 3081 } break; 3082 3083 // Uninitialized_variable_info { 3084 // u1 tag = ITEM_Uninitialized; /* 8 */ 3085 // u2 offset; 3086 // } 3087 case ITEM_Uninitialized: 3088 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset"); 3089 stackmap_p_ref += 2; 3090 break; 3091 3092 default: 3093 log_debug(redefine, class, stackmap)("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag); 3094 ShouldNotReachHere(); 3095 break; 3096 } // end switch (tag) 3097 } // end rewrite_cp_refs_in_verification_type_info() 3098 3099 3100 // Change the constant pool associated with klass scratch_class to 3101 // scratch_cp. If shrink is true, then scratch_cp_length elements 3102 // are copied from scratch_cp to a smaller constant pool and the 3103 // smaller constant pool is associated with scratch_class. 3104 void VM_RedefineClasses::set_new_constant_pool( 3105 ClassLoaderData* loader_data, 3106 InstanceKlass* scratch_class, constantPoolHandle scratch_cp, 3107 int scratch_cp_length, TRAPS) { 3108 assert(scratch_cp->length() >= scratch_cp_length, "sanity check"); 3109 3110 // scratch_cp is a merged constant pool and has enough space for a 3111 // worst case merge situation. We want to associate the minimum 3112 // sized constant pool with the klass to save space. 3113 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK); 3114 constantPoolHandle smaller_cp(THREAD, cp); 3115 3116 // preserve version() value in the smaller copy 3117 int version = scratch_cp->version(); 3118 assert(version != 0, "sanity check"); 3119 smaller_cp->set_version(version); 3120 3121 // attach klass to new constant pool 3122 // reference to the cp holder is needed for copy_operands() 3123 smaller_cp->set_pool_holder(scratch_class); 3124 3125 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD); 3126 if (HAS_PENDING_EXCEPTION) { 3127 // Exception is handled in the caller 3128 loader_data->add_to_deallocate_list(smaller_cp()); 3129 return; 3130 } 3131 scratch_cp = smaller_cp; 3132 3133 // attach new constant pool to klass 3134 scratch_class->set_constants(scratch_cp()); 3135 scratch_cp->initialize_unresolved_klasses(loader_data, CHECK); 3136 3137 int i; // for portability 3138 3139 // update each field in klass to use new constant pool indices as needed 3140 for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) { 3141 jshort cur_index = fs.name_index(); 3142 jshort new_index = find_new_index(cur_index); 3143 if (new_index != 0) { 3144 log_trace(redefine, class, constantpool)("field-name_index change: %d to %d", cur_index, new_index); 3145 fs.set_name_index(new_index); 3146 } 3147 cur_index = fs.signature_index(); 3148 new_index = find_new_index(cur_index); 3149 if (new_index != 0) { 3150 log_trace(redefine, class, constantpool)("field-signature_index change: %d to %d", cur_index, new_index); 3151 fs.set_signature_index(new_index); 3152 } 3153 cur_index = fs.initval_index(); 3154 new_index = find_new_index(cur_index); 3155 if (new_index != 0) { 3156 log_trace(redefine, class, constantpool)("field-initval_index change: %d to %d", cur_index, new_index); 3157 fs.set_initval_index(new_index); 3158 } 3159 cur_index = fs.generic_signature_index(); 3160 new_index = find_new_index(cur_index); 3161 if (new_index != 0) { 3162 log_trace(redefine, class, constantpool)("field-generic_signature change: %d to %d", cur_index, new_index); 3163 fs.set_generic_signature_index(new_index); 3164 } 3165 } // end for each field 3166 3167 // Update constant pool indices in the inner classes info to use 3168 // new constant indices as needed. The inner classes info is a 3169 // quadruple: 3170 // (inner_class_info, outer_class_info, inner_name, inner_access_flags) 3171 InnerClassesIterator iter(scratch_class); 3172 for (; !iter.done(); iter.next()) { 3173 int cur_index = iter.inner_class_info_index(); 3174 if (cur_index == 0) { 3175 continue; // JVM spec. allows null inner class refs so skip it 3176 } 3177 int new_index = find_new_index(cur_index); 3178 if (new_index != 0) { 3179 log_trace(redefine, class, constantpool)("inner_class_info change: %d to %d", cur_index, new_index); 3180 iter.set_inner_class_info_index(new_index); 3181 } 3182 cur_index = iter.outer_class_info_index(); 3183 new_index = find_new_index(cur_index); 3184 if (new_index != 0) { 3185 log_trace(redefine, class, constantpool)("outer_class_info change: %d to %d", cur_index, new_index); 3186 iter.set_outer_class_info_index(new_index); 3187 } 3188 cur_index = iter.inner_name_index(); 3189 new_index = find_new_index(cur_index); 3190 if (new_index != 0) { 3191 log_trace(redefine, class, constantpool)("inner_name change: %d to %d", cur_index, new_index); 3192 iter.set_inner_name_index(new_index); 3193 } 3194 } // end for each inner class 3195 3196 // Attach each method in klass to the new constant pool and update 3197 // to use new constant pool indices as needed: 3198 Array<Method*>* methods = scratch_class->methods(); 3199 for (i = methods->length() - 1; i >= 0; i--) { 3200 methodHandle method(THREAD, methods->at(i)); 3201 method->set_constants(scratch_cp()); 3202 3203 int new_index = find_new_index(method->name_index()); 3204 if (new_index != 0) { 3205 log_trace(redefine, class, constantpool) 3206 ("method-name_index change: %d to %d", method->name_index(), new_index); 3207 method->set_name_index(new_index); 3208 } 3209 new_index = find_new_index(method->signature_index()); 3210 if (new_index != 0) { 3211 log_trace(redefine, class, constantpool) 3212 ("method-signature_index change: %d to %d", method->signature_index(), new_index); 3213 method->set_signature_index(new_index); 3214 } 3215 new_index = find_new_index(method->generic_signature_index()); 3216 if (new_index != 0) { 3217 log_trace(redefine, class, constantpool) 3218 ("method-generic_signature_index change: %d to %d", method->generic_signature_index(), new_index); 3219 method->set_generic_signature_index(new_index); 3220 } 3221 3222 // Update constant pool indices in the method's checked exception 3223 // table to use new constant indices as needed. 3224 int cext_length = method->checked_exceptions_length(); 3225 if (cext_length > 0) { 3226 CheckedExceptionElement * cext_table = 3227 method->checked_exceptions_start(); 3228 for (int j = 0; j < cext_length; j++) { 3229 int cur_index = cext_table[j].class_cp_index; 3230 int new_index = find_new_index(cur_index); 3231 if (new_index != 0) { 3232 log_trace(redefine, class, constantpool)("cext-class_cp_index change: %d to %d", cur_index, new_index); 3233 cext_table[j].class_cp_index = (u2)new_index; 3234 } 3235 } // end for each checked exception table entry 3236 } // end if there are checked exception table entries 3237 3238 // Update each catch type index in the method's exception table 3239 // to use new constant pool indices as needed. The exception table 3240 // holds quadruple entries of the form: 3241 // (beg_bci, end_bci, handler_bci, klass_index) 3242 3243 ExceptionTable ex_table(method()); 3244 int ext_length = ex_table.length(); 3245 3246 for (int j = 0; j < ext_length; j ++) { 3247 int cur_index = ex_table.catch_type_index(j); 3248 int new_index = find_new_index(cur_index); 3249 if (new_index != 0) { 3250 log_trace(redefine, class, constantpool)("ext-klass_index change: %d to %d", cur_index, new_index); 3251 ex_table.set_catch_type_index(j, new_index); 3252 } 3253 } // end for each exception table entry 3254 3255 // Update constant pool indices in the method's local variable 3256 // table to use new constant indices as needed. The local variable 3257 // table hold sextuple entries of the form: 3258 // (start_pc, length, name_index, descriptor_index, signature_index, slot) 3259 int lvt_length = method->localvariable_table_length(); 3260 if (lvt_length > 0) { 3261 LocalVariableTableElement * lv_table = 3262 method->localvariable_table_start(); 3263 for (int j = 0; j < lvt_length; j++) { 3264 int cur_index = lv_table[j].name_cp_index; 3265 int new_index = find_new_index(cur_index); 3266 if (new_index != 0) { 3267 log_trace(redefine, class, constantpool)("lvt-name_cp_index change: %d to %d", cur_index, new_index); 3268 lv_table[j].name_cp_index = (u2)new_index; 3269 } 3270 cur_index = lv_table[j].descriptor_cp_index; 3271 new_index = find_new_index(cur_index); 3272 if (new_index != 0) { 3273 log_trace(redefine, class, constantpool)("lvt-descriptor_cp_index change: %d to %d", cur_index, new_index); 3274 lv_table[j].descriptor_cp_index = (u2)new_index; 3275 } 3276 cur_index = lv_table[j].signature_cp_index; 3277 new_index = find_new_index(cur_index); 3278 if (new_index != 0) { 3279 log_trace(redefine, class, constantpool)("lvt-signature_cp_index change: %d to %d", cur_index, new_index); 3280 lv_table[j].signature_cp_index = (u2)new_index; 3281 } 3282 } // end for each local variable table entry 3283 } // end if there are local variable table entries 3284 3285 rewrite_cp_refs_in_stack_map_table(method, THREAD); 3286 } // end for each method 3287 } // end set_new_constant_pool() 3288 3289 3290 // Unevolving classes may point to methods of the_class directly 3291 // from their constant pool caches, itables, and/or vtables. We 3292 // use the ClassLoaderDataGraph::classes_do() facility and this helper 3293 // to fix up these pointers. 3294 3295 // Adjust cpools and vtables closure 3296 void VM_RedefineClasses::AdjustCpoolCacheAndVtable::do_klass(Klass* k) { 3297 3298 // This is a very busy routine. We don't want too much tracing 3299 // printed out. 3300 bool trace_name_printed = false; 3301 InstanceKlass *the_class = InstanceKlass::cast(_the_class); 3302 3303 // If the class being redefined is java.lang.Object, we need to fix all 3304 // array class vtables also 3305 if (k->is_array_klass() && _the_class == SystemDictionary::Object_klass()) { 3306 k->vtable().adjust_method_entries(the_class, &trace_name_printed); 3307 3308 } else if (k->is_instance_klass()) { 3309 HandleMark hm(_thread); 3310 InstanceKlass *ik = InstanceKlass::cast(k); 3311 3312 // HotSpot specific optimization! HotSpot does not currently 3313 // support delegation from the bootstrap class loader to a 3314 // user-defined class loader. This means that if the bootstrap 3315 // class loader is the initiating class loader, then it will also 3316 // be the defining class loader. This also means that classes 3317 // loaded by the bootstrap class loader cannot refer to classes 3318 // loaded by a user-defined class loader. Note: a user-defined 3319 // class loader can delegate to the bootstrap class loader. 3320 // 3321 // If the current class being redefined has a user-defined class 3322 // loader as its defining class loader, then we can skip all 3323 // classes loaded by the bootstrap class loader. 3324 bool is_user_defined = (_the_class->class_loader() != NULL); 3325 if (is_user_defined && ik->class_loader() == NULL) { 3326 return; 3327 } 3328 3329 // Fix the vtable embedded in the_class and subclasses of the_class, 3330 // if one exists. We discard scratch_class and we don't keep an 3331 // InstanceKlass around to hold obsolete methods so we don't have 3332 // any other InstanceKlass embedded vtables to update. The vtable 3333 // holds the Method*s for virtual (but not final) methods. 3334 // Default methods, or concrete methods in interfaces are stored 3335 // in the vtable, so if an interface changes we need to check 3336 // adjust_method_entries() for every InstanceKlass, which will also 3337 // adjust the default method vtable indices. 3338 // We also need to adjust any default method entries that are 3339 // not yet in the vtable, because the vtable setup is in progress. 3340 // This must be done after we adjust the default_methods and 3341 // default_vtable_indices for methods already in the vtable. 3342 // If redefining Unsafe, walk all the vtables looking for entries. 3343 if (ik->vtable_length() > 0 && (_the_class->is_interface() 3344 || _the_class == SystemDictionary::internal_Unsafe_klass() 3345 || ik->is_subtype_of(_the_class))) { 3346 // ik->vtable() creates a wrapper object; rm cleans it up 3347 ResourceMark rm(_thread); 3348 3349 ik->vtable().adjust_method_entries(the_class, &trace_name_printed); 3350 ik->adjust_default_methods(the_class, &trace_name_printed); 3351 } 3352 3353 // If the current class has an itable and we are either redefining an 3354 // interface or if the current class is a subclass of the_class, then 3355 // we potentially have to fix the itable. If we are redefining an 3356 // interface, then we have to call adjust_method_entries() for 3357 // every InstanceKlass that has an itable since there isn't a 3358 // subclass relationship between an interface and an InstanceKlass. 3359 // If redefining Unsafe, walk all the itables looking for entries. 3360 if (ik->itable_length() > 0 && (_the_class->is_interface() 3361 || _the_class == SystemDictionary::internal_Unsafe_klass() 3362 || ik->is_subclass_of(_the_class))) { 3363 ResourceMark rm(_thread); 3364 ik->itable().adjust_method_entries(the_class, &trace_name_printed); 3365 } 3366 3367 // The constant pools in other classes (other_cp) can refer to 3368 // methods in the_class. We have to update method information in 3369 // other_cp's cache. If other_cp has a previous version, then we 3370 // have to repeat the process for each previous version. The 3371 // constant pool cache holds the Method*s for non-virtual 3372 // methods and for virtual, final methods. 3373 // 3374 // Special case: if the current class is the_class, then new_cp 3375 // has already been attached to the_class and old_cp has already 3376 // been added as a previous version. The new_cp doesn't have any 3377 // cached references to old methods so it doesn't need to be 3378 // updated. We can simply start with the previous version(s) in 3379 // that case. 3380 constantPoolHandle other_cp; 3381 ConstantPoolCache* cp_cache; 3382 3383 if (ik != _the_class) { 3384 // this klass' constant pool cache may need adjustment 3385 other_cp = constantPoolHandle(ik->constants()); 3386 cp_cache = other_cp->cache(); 3387 if (cp_cache != NULL) { 3388 cp_cache->adjust_method_entries(the_class, &trace_name_printed); 3389 } 3390 } 3391 3392 // the previous versions' constant pool caches may need adjustment 3393 for (InstanceKlass* pv_node = ik->previous_versions(); 3394 pv_node != NULL; 3395 pv_node = pv_node->previous_versions()) { 3396 cp_cache = pv_node->constants()->cache(); 3397 if (cp_cache != NULL) { 3398 cp_cache->adjust_method_entries(pv_node, &trace_name_printed); 3399 } 3400 } 3401 } 3402 } 3403 3404 // Clean method data for this class 3405 void VM_RedefineClasses::MethodDataCleaner::do_klass(Klass* k) { 3406 if (k->is_instance_klass()) { 3407 InstanceKlass *ik = InstanceKlass::cast(k); 3408 // Clean MethodData of this class's methods so they don't refer to 3409 // old methods that are no longer running. 3410 Array<Method*>* methods = ik->methods(); 3411 int num_methods = methods->length(); 3412 for (int index = 0; index < num_methods; ++index) { 3413 if (methods->at(index)->method_data() != NULL) { 3414 methods->at(index)->method_data()->clean_weak_method_links(); 3415 } 3416 } 3417 } 3418 } 3419 3420 void VM_RedefineClasses::update_jmethod_ids() { 3421 for (int j = 0; j < _matching_methods_length; ++j) { 3422 Method* old_method = _matching_old_methods[j]; 3423 jmethodID jmid = old_method->find_jmethod_id_or_null(); 3424 if (jmid != NULL) { 3425 // There is a jmethodID, change it to point to the new method 3426 methodHandle new_method_h(_matching_new_methods[j]); 3427 Method::change_method_associated_with_jmethod_id(jmid, new_method_h()); 3428 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j], 3429 "should be replaced"); 3430 } 3431 } 3432 } 3433 3434 int VM_RedefineClasses::check_methods_and_mark_as_obsolete() { 3435 int emcp_method_count = 0; 3436 int obsolete_count = 0; 3437 int old_index = 0; 3438 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) { 3439 Method* old_method = _matching_old_methods[j]; 3440 Method* new_method = _matching_new_methods[j]; 3441 Method* old_array_method; 3442 3443 // Maintain an old_index into the _old_methods array by skipping 3444 // deleted methods 3445 while ((old_array_method = _old_methods->at(old_index)) != old_method) { 3446 ++old_index; 3447 } 3448 3449 if (MethodComparator::methods_EMCP(old_method, new_method)) { 3450 // The EMCP definition from JSR-163 requires the bytecodes to be 3451 // the same with the exception of constant pool indices which may 3452 // differ. However, the constants referred to by those indices 3453 // must be the same. 3454 // 3455 // We use methods_EMCP() for comparison since constant pool 3456 // merging can remove duplicate constant pool entries that were 3457 // present in the old method and removed from the rewritten new 3458 // method. A faster binary comparison function would consider the 3459 // old and new methods to be different when they are actually 3460 // EMCP. 3461 // 3462 // The old and new methods are EMCP and you would think that we 3463 // could get rid of one of them here and now and save some space. 3464 // However, the concept of EMCP only considers the bytecodes and 3465 // the constant pool entries in the comparison. Other things, 3466 // e.g., the line number table (LNT) or the local variable table 3467 // (LVT) don't count in the comparison. So the new (and EMCP) 3468 // method can have a new LNT that we need so we can't just 3469 // overwrite the new method with the old method. 3470 // 3471 // When this routine is called, we have already attached the new 3472 // methods to the_class so the old methods are effectively 3473 // overwritten. However, if an old method is still executing, 3474 // then the old method cannot be collected until sometime after 3475 // the old method call has returned. So the overwriting of old 3476 // methods by new methods will save us space except for those 3477 // (hopefully few) old methods that are still executing. 3478 // 3479 // A method refers to a ConstMethod* and this presents another 3480 // possible avenue to space savings. The ConstMethod* in the 3481 // new method contains possibly new attributes (LNT, LVT, etc). 3482 // At first glance, it seems possible to save space by replacing 3483 // the ConstMethod* in the old method with the ConstMethod* 3484 // from the new method. The old and new methods would share the 3485 // same ConstMethod* and we would save the space occupied by 3486 // the old ConstMethod*. However, the ConstMethod* contains 3487 // a back reference to the containing method. Sharing the 3488 // ConstMethod* between two methods could lead to confusion in 3489 // the code that uses the back reference. This would lead to 3490 // brittle code that could be broken in non-obvious ways now or 3491 // in the future. 3492 // 3493 // Another possibility is to copy the ConstMethod* from the new 3494 // method to the old method and then overwrite the new method with 3495 // the old method. Since the ConstMethod* contains the bytecodes 3496 // for the method embedded in the oop, this option would change 3497 // the bytecodes out from under any threads executing the old 3498 // method and make the thread's bcp invalid. Since EMCP requires 3499 // that the bytecodes be the same modulo constant pool indices, it 3500 // is straight forward to compute the correct new bcp in the new 3501 // ConstMethod* from the old bcp in the old ConstMethod*. The 3502 // time consuming part would be searching all the frames in all 3503 // of the threads to find all of the calls to the old method. 3504 // 3505 // It looks like we will have to live with the limited savings 3506 // that we get from effectively overwriting the old methods 3507 // when the new methods are attached to the_class. 3508 3509 // Count number of methods that are EMCP. The method will be marked 3510 // old but not obsolete if it is EMCP. 3511 emcp_method_count++; 3512 3513 // An EMCP method is _not_ obsolete. An obsolete method has a 3514 // different jmethodID than the current method. An EMCP method 3515 // has the same jmethodID as the current method. Having the 3516 // same jmethodID for all EMCP versions of a method allows for 3517 // a consistent view of the EMCP methods regardless of which 3518 // EMCP method you happen to have in hand. For example, a 3519 // breakpoint set in one EMCP method will work for all EMCP 3520 // versions of the method including the current one. 3521 } else { 3522 // mark obsolete methods as such 3523 old_method->set_is_obsolete(); 3524 obsolete_count++; 3525 3526 // obsolete methods need a unique idnum so they become new entries in 3527 // the jmethodID cache in InstanceKlass 3528 assert(old_method->method_idnum() == new_method->method_idnum(), "must match"); 3529 u2 num = InstanceKlass::cast(_the_class)->next_method_idnum(); 3530 if (num != ConstMethod::UNSET_IDNUM) { 3531 old_method->set_method_idnum(num); 3532 } 3533 3534 // With tracing we try not to "yack" too much. The position of 3535 // this trace assumes there are fewer obsolete methods than 3536 // EMCP methods. 3537 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) { 3538 ResourceMark rm; 3539 log_trace(redefine, class, obsolete, mark) 3540 ("mark %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string()); 3541 } 3542 } 3543 old_method->set_is_old(); 3544 } 3545 for (int i = 0; i < _deleted_methods_length; ++i) { 3546 Method* old_method = _deleted_methods[i]; 3547 3548 assert(!old_method->has_vtable_index(), 3549 "cannot delete methods with vtable entries");; 3550 3551 // Mark all deleted methods as old, obsolete and deleted 3552 old_method->set_is_deleted(); 3553 old_method->set_is_old(); 3554 old_method->set_is_obsolete(); 3555 ++obsolete_count; 3556 // With tracing we try not to "yack" too much. The position of 3557 // this trace assumes there are fewer obsolete methods than 3558 // EMCP methods. 3559 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) { 3560 ResourceMark rm; 3561 log_trace(redefine, class, obsolete, mark) 3562 ("mark deleted %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string()); 3563 } 3564 } 3565 assert((emcp_method_count + obsolete_count) == _old_methods->length(), 3566 "sanity check"); 3567 log_trace(redefine, class, obsolete, mark)("EMCP_cnt=%d, obsolete_cnt=%d", emcp_method_count, obsolete_count); 3568 return emcp_method_count; 3569 } 3570 3571 // This internal class transfers the native function registration from old methods 3572 // to new methods. It is designed to handle both the simple case of unchanged 3573 // native methods and the complex cases of native method prefixes being added and/or 3574 // removed. 3575 // It expects only to be used during the VM_RedefineClasses op (a safepoint). 3576 // 3577 // This class is used after the new methods have been installed in "the_class". 3578 // 3579 // So, for example, the following must be handled. Where 'm' is a method and 3580 // a number followed by an underscore is a prefix. 3581 // 3582 // Old Name New Name 3583 // Simple transfer to new method m -> m 3584 // Add prefix m -> 1_m 3585 // Remove prefix 1_m -> m 3586 // Simultaneous add of prefixes m -> 3_2_1_m 3587 // Simultaneous removal of prefixes 3_2_1_m -> m 3588 // Simultaneous add and remove 1_m -> 2_m 3589 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m 3590 // 3591 class TransferNativeFunctionRegistration { 3592 private: 3593 InstanceKlass* the_class; 3594 int prefix_count; 3595 char** prefixes; 3596 3597 // Recursively search the binary tree of possibly prefixed method names. 3598 // Iteration could be used if all agents were well behaved. Full tree walk is 3599 // more resilent to agents not cleaning up intermediate methods. 3600 // Branch at each depth in the binary tree is: 3601 // (1) without the prefix. 3602 // (2) with the prefix. 3603 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...) 3604 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len, 3605 Symbol* signature) { 3606 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len); 3607 if (name_symbol != NULL) { 3608 Method* method = the_class->lookup_method(name_symbol, signature); 3609 if (method != NULL) { 3610 // Even if prefixed, intermediate methods must exist. 3611 if (method->is_native()) { 3612 // Wahoo, we found a (possibly prefixed) version of the method, return it. 3613 return method; 3614 } 3615 if (depth < prefix_count) { 3616 // Try applying further prefixes (other than this one). 3617 method = search_prefix_name_space(depth+1, name_str, name_len, signature); 3618 if (method != NULL) { 3619 return method; // found 3620 } 3621 3622 // Try adding this prefix to the method name and see if it matches 3623 // another method name. 3624 char* prefix = prefixes[depth]; 3625 size_t prefix_len = strlen(prefix); 3626 size_t trial_len = name_len + prefix_len; 3627 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1); 3628 strcpy(trial_name_str, prefix); 3629 strcat(trial_name_str, name_str); 3630 method = search_prefix_name_space(depth+1, trial_name_str, trial_len, 3631 signature); 3632 if (method != NULL) { 3633 // If found along this branch, it was prefixed, mark as such 3634 method->set_is_prefixed_native(); 3635 return method; // found 3636 } 3637 } 3638 } 3639 } 3640 return NULL; // This whole branch bore nothing 3641 } 3642 3643 // Return the method name with old prefixes stripped away. 3644 char* method_name_without_prefixes(Method* method) { 3645 Symbol* name = method->name(); 3646 char* name_str = name->as_utf8(); 3647 3648 // Old prefixing may be defunct, strip prefixes, if any. 3649 for (int i = prefix_count-1; i >= 0; i--) { 3650 char* prefix = prefixes[i]; 3651 size_t prefix_len = strlen(prefix); 3652 if (strncmp(prefix, name_str, prefix_len) == 0) { 3653 name_str += prefix_len; 3654 } 3655 } 3656 return name_str; 3657 } 3658 3659 // Strip any prefixes off the old native method, then try to find a 3660 // (possibly prefixed) new native that matches it. 3661 Method* strip_and_search_for_new_native(Method* method) { 3662 ResourceMark rm; 3663 char* name_str = method_name_without_prefixes(method); 3664 return search_prefix_name_space(0, name_str, strlen(name_str), 3665 method->signature()); 3666 } 3667 3668 public: 3669 3670 // Construct a native method transfer processor for this class. 3671 TransferNativeFunctionRegistration(InstanceKlass* _the_class) { 3672 assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); 3673 3674 the_class = _the_class; 3675 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count); 3676 } 3677 3678 // Attempt to transfer any of the old or deleted methods that are native 3679 void transfer_registrations(Method** old_methods, int methods_length) { 3680 for (int j = 0; j < methods_length; j++) { 3681 Method* old_method = old_methods[j]; 3682 3683 if (old_method->is_native() && old_method->has_native_function()) { 3684 Method* new_method = strip_and_search_for_new_native(old_method); 3685 if (new_method != NULL) { 3686 // Actually set the native function in the new method. 3687 // Redefine does not send events (except CFLH), certainly not this 3688 // behind the scenes re-registration. 3689 new_method->set_native_function(old_method->native_function(), 3690 !Method::native_bind_event_is_interesting); 3691 } 3692 } 3693 } 3694 } 3695 }; 3696 3697 // Don't lose the association between a native method and its JNI function. 3698 void VM_RedefineClasses::transfer_old_native_function_registrations(InstanceKlass* the_class) { 3699 TransferNativeFunctionRegistration transfer(the_class); 3700 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length); 3701 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length); 3702 } 3703 3704 // Deoptimize all compiled code that depends on this class. 3705 // 3706 // If the can_redefine_classes capability is obtained in the onload 3707 // phase then the compiler has recorded all dependencies from startup. 3708 // In that case we need only deoptimize and throw away all compiled code 3709 // that depends on the class. 3710 // 3711 // If can_redefine_classes is obtained sometime after the onload 3712 // phase then the dependency information may be incomplete. In that case 3713 // the first call to RedefineClasses causes all compiled code to be 3714 // thrown away. As can_redefine_classes has been obtained then 3715 // all future compilations will record dependencies so second and 3716 // subsequent calls to RedefineClasses need only throw away code 3717 // that depends on the class. 3718 // 3719 void VM_RedefineClasses::flush_dependent_code(InstanceKlass* ik, TRAPS) { 3720 assert_locked_or_safepoint(Compile_lock); 3721 3722 // All dependencies have been recorded from startup or this is a second or 3723 // subsequent use of RedefineClasses 3724 if (JvmtiExport::all_dependencies_are_recorded()) { 3725 CodeCache::flush_evol_dependents_on(ik); 3726 } else { 3727 CodeCache::mark_all_nmethods_for_deoptimization(); 3728 3729 ResourceMark rm(THREAD); 3730 DeoptimizationMarker dm; 3731 3732 // Deoptimize all activations depending on marked nmethods 3733 Deoptimization::deoptimize_dependents(); 3734 3735 // Make the dependent methods not entrant 3736 CodeCache::make_marked_nmethods_not_entrant(); 3737 3738 // From now on we know that the dependency information is complete 3739 JvmtiExport::set_all_dependencies_are_recorded(true); 3740 } 3741 } 3742 3743 void VM_RedefineClasses::compute_added_deleted_matching_methods() { 3744 Method* old_method; 3745 Method* new_method; 3746 3747 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 3748 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 3749 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length()); 3750 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 3751 3752 _matching_methods_length = 0; 3753 _deleted_methods_length = 0; 3754 _added_methods_length = 0; 3755 3756 int nj = 0; 3757 int oj = 0; 3758 while (true) { 3759 if (oj >= _old_methods->length()) { 3760 if (nj >= _new_methods->length()) { 3761 break; // we've looked at everything, done 3762 } 3763 // New method at the end 3764 new_method = _new_methods->at(nj); 3765 _added_methods[_added_methods_length++] = new_method; 3766 ++nj; 3767 } else if (nj >= _new_methods->length()) { 3768 // Old method, at the end, is deleted 3769 old_method = _old_methods->at(oj); 3770 _deleted_methods[_deleted_methods_length++] = old_method; 3771 ++oj; 3772 } else { 3773 old_method = _old_methods->at(oj); 3774 new_method = _new_methods->at(nj); 3775 if (old_method->name() == new_method->name()) { 3776 if (old_method->signature() == new_method->signature()) { 3777 _matching_old_methods[_matching_methods_length ] = old_method; 3778 _matching_new_methods[_matching_methods_length++] = new_method; 3779 ++nj; 3780 ++oj; 3781 } else { 3782 // added overloaded have already been moved to the end, 3783 // so this is a deleted overloaded method 3784 _deleted_methods[_deleted_methods_length++] = old_method; 3785 ++oj; 3786 } 3787 } else { // names don't match 3788 if (old_method->name()->fast_compare(new_method->name()) > 0) { 3789 // new method 3790 _added_methods[_added_methods_length++] = new_method; 3791 ++nj; 3792 } else { 3793 // deleted method 3794 _deleted_methods[_deleted_methods_length++] = old_method; 3795 ++oj; 3796 } 3797 } 3798 } 3799 } 3800 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity"); 3801 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity"); 3802 } 3803 3804 3805 void VM_RedefineClasses::swap_annotations(InstanceKlass* the_class, 3806 InstanceKlass* scratch_class) { 3807 // Swap annotation fields values 3808 Annotations* old_annotations = the_class->annotations(); 3809 the_class->set_annotations(scratch_class->annotations()); 3810 scratch_class->set_annotations(old_annotations); 3811 } 3812 3813 3814 // Install the redefinition of a class: 3815 // - house keeping (flushing breakpoints and caches, deoptimizing 3816 // dependent compiled code) 3817 // - replacing parts in the_class with parts from scratch_class 3818 // - adding a weak reference to track the obsolete but interesting 3819 // parts of the_class 3820 // - adjusting constant pool caches and vtables in other classes 3821 // that refer to methods in the_class. These adjustments use the 3822 // ClassLoaderDataGraph::classes_do() facility which only allows 3823 // a helper method to be specified. The interesting parameters 3824 // that we would like to pass to the helper method are saved in 3825 // static global fields in the VM operation. 3826 void VM_RedefineClasses::redefine_single_class(jclass the_jclass, 3827 InstanceKlass* scratch_class, TRAPS) { 3828 3829 HandleMark hm(THREAD); // make sure handles from this call are freed 3830 3831 if (log_is_enabled(Info, redefine, class, timer)) { 3832 _timer_rsc_phase1.start(); 3833 } 3834 3835 InstanceKlass* the_class = get_ik(the_jclass); 3836 3837 // Remove all breakpoints in methods of this class 3838 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints(); 3839 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class); 3840 3841 // Deoptimize all compiled code that depends on this class 3842 flush_dependent_code(the_class, THREAD); 3843 3844 _old_methods = the_class->methods(); 3845 _new_methods = scratch_class->methods(); 3846 _the_class = the_class; 3847 compute_added_deleted_matching_methods(); 3848 update_jmethod_ids(); 3849 3850 _any_class_has_resolved_methods = the_class->has_resolved_methods() || _any_class_has_resolved_methods; 3851 3852 // Attach new constant pool to the original klass. The original 3853 // klass still refers to the old constant pool (for now). 3854 scratch_class->constants()->set_pool_holder(the_class); 3855 3856 #if 0 3857 // In theory, with constant pool merging in place we should be able 3858 // to save space by using the new, merged constant pool in place of 3859 // the old constant pool(s). By "pool(s)" I mean the constant pool in 3860 // the klass version we are replacing now and any constant pool(s) in 3861 // previous versions of klass. Nice theory, doesn't work in practice. 3862 // When this code is enabled, even simple programs throw NullPointer 3863 // exceptions. I'm guessing that this is caused by some constant pool 3864 // cache difference between the new, merged constant pool and the 3865 // constant pool that was just being used by the klass. I'm keeping 3866 // this code around to archive the idea, but the code has to remain 3867 // disabled for now. 3868 3869 // Attach each old method to the new constant pool. This can be 3870 // done here since we are past the bytecode verification and 3871 // constant pool optimization phases. 3872 for (int i = _old_methods->length() - 1; i >= 0; i--) { 3873 Method* method = _old_methods->at(i); 3874 method->set_constants(scratch_class->constants()); 3875 } 3876 3877 // NOTE: this doesn't work because you can redefine the same class in two 3878 // threads, each getting their own constant pool data appended to the 3879 // original constant pool. In order for the new methods to work when they 3880 // become old methods, they need to keep their updated copy of the constant pool. 3881 3882 { 3883 // walk all previous versions of the klass 3884 InstanceKlass *ik = the_class; 3885 PreviousVersionWalker pvw(ik); 3886 do { 3887 ik = pvw.next_previous_version(); 3888 if (ik != NULL) { 3889 3890 // attach previous version of klass to the new constant pool 3891 ik->set_constants(scratch_class->constants()); 3892 3893 // Attach each method in the previous version of klass to the 3894 // new constant pool 3895 Array<Method*>* prev_methods = ik->methods(); 3896 for (int i = prev_methods->length() - 1; i >= 0; i--) { 3897 Method* method = prev_methods->at(i); 3898 method->set_constants(scratch_class->constants()); 3899 } 3900 } 3901 } while (ik != NULL); 3902 } 3903 #endif 3904 3905 // Replace methods and constantpool 3906 the_class->set_methods(_new_methods); 3907 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods, 3908 // and to be able to undo operation easily. 3909 3910 Array<int>* old_ordering = the_class->method_ordering(); 3911 the_class->set_method_ordering(scratch_class->method_ordering()); 3912 scratch_class->set_method_ordering(old_ordering); 3913 3914 ConstantPool* old_constants = the_class->constants(); 3915 the_class->set_constants(scratch_class->constants()); 3916 scratch_class->set_constants(old_constants); // See the previous comment. 3917 #if 0 3918 // We are swapping the guts of "the new class" with the guts of "the 3919 // class". Since the old constant pool has just been attached to "the 3920 // new class", it seems logical to set the pool holder in the old 3921 // constant pool also. However, doing this will change the observable 3922 // class hierarchy for any old methods that are still executing. A 3923 // method can query the identity of its "holder" and this query uses 3924 // the method's constant pool link to find the holder. The change in 3925 // holding class from "the class" to "the new class" can confuse 3926 // things. 3927 // 3928 // Setting the old constant pool's holder will also cause 3929 // verification done during vtable initialization below to fail. 3930 // During vtable initialization, the vtable's class is verified to be 3931 // a subtype of the method's holder. The vtable's class is "the 3932 // class" and the method's holder is gotten from the constant pool 3933 // link in the method itself. For "the class"'s directly implemented 3934 // methods, the method holder is "the class" itself (as gotten from 3935 // the new constant pool). The check works fine in this case. The 3936 // check also works fine for methods inherited from super classes. 3937 // 3938 // Miranda methods are a little more complicated. A miranda method is 3939 // provided by an interface when the class implementing the interface 3940 // does not provide its own method. These interfaces are implemented 3941 // internally as an InstanceKlass. These special instanceKlasses 3942 // share the constant pool of the class that "implements" the 3943 // interface. By sharing the constant pool, the method holder of a 3944 // miranda method is the class that "implements" the interface. In a 3945 // non-redefine situation, the subtype check works fine. However, if 3946 // the old constant pool's pool holder is modified, then the check 3947 // fails because there is no class hierarchy relationship between the 3948 // vtable's class and "the new class". 3949 3950 old_constants->set_pool_holder(scratch_class()); 3951 #endif 3952 3953 // track number of methods that are EMCP for add_previous_version() call below 3954 int emcp_method_count = check_methods_and_mark_as_obsolete(); 3955 transfer_old_native_function_registrations(the_class); 3956 3957 // The class file bytes from before any retransformable agents mucked 3958 // with them was cached on the scratch class, move to the_class. 3959 // Note: we still want to do this if nothing needed caching since it 3960 // should get cleared in the_class too. 3961 if (the_class->get_cached_class_file() == 0) { 3962 // the_class doesn't have a cache yet so copy it 3963 the_class->set_cached_class_file(scratch_class->get_cached_class_file()); 3964 } 3965 else if (scratch_class->get_cached_class_file() != 3966 the_class->get_cached_class_file()) { 3967 // The same class can be present twice in the scratch classes list or there 3968 // are multiple concurrent RetransformClasses calls on different threads. 3969 // In such cases we have to deallocate scratch_class cached_class_file. 3970 os::free(scratch_class->get_cached_class_file()); 3971 } 3972 3973 // NULL out in scratch class to not delete twice. The class to be redefined 3974 // always owns these bytes. 3975 scratch_class->set_cached_class_file(NULL); 3976 3977 // Replace inner_classes 3978 Array<u2>* old_inner_classes = the_class->inner_classes(); 3979 the_class->set_inner_classes(scratch_class->inner_classes()); 3980 scratch_class->set_inner_classes(old_inner_classes); 3981 3982 // Initialize the vtable and interface table after 3983 // methods have been rewritten 3984 { 3985 ResourceMark rm(THREAD); 3986 // no exception should happen here since we explicitly 3987 // do not check loader constraints. 3988 // compare_and_normalize_class_versions has already checked: 3989 // - classloaders unchanged, signatures unchanged 3990 // - all instanceKlasses for redefined classes reused & contents updated 3991 the_class->vtable().initialize_vtable(false, THREAD); 3992 the_class->itable().initialize_itable(false, THREAD); 3993 assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())), "redefine exception"); 3994 } 3995 3996 // Leave arrays of jmethodIDs and itable index cache unchanged 3997 3998 // Copy the "source file name" attribute from new class version 3999 the_class->set_source_file_name_index( 4000 scratch_class->source_file_name_index()); 4001 4002 // Copy the "source debug extension" attribute from new class version 4003 the_class->set_source_debug_extension( 4004 scratch_class->source_debug_extension(), 4005 scratch_class->source_debug_extension() == NULL ? 0 : 4006 (int)strlen(scratch_class->source_debug_extension())); 4007 4008 // Use of javac -g could be different in the old and the new 4009 if (scratch_class->access_flags().has_localvariable_table() != 4010 the_class->access_flags().has_localvariable_table()) { 4011 4012 AccessFlags flags = the_class->access_flags(); 4013 if (scratch_class->access_flags().has_localvariable_table()) { 4014 flags.set_has_localvariable_table(); 4015 } else { 4016 flags.clear_has_localvariable_table(); 4017 } 4018 the_class->set_access_flags(flags); 4019 } 4020 4021 swap_annotations(the_class, scratch_class); 4022 4023 // Replace minor version number of class file 4024 u2 old_minor_version = the_class->minor_version(); 4025 the_class->set_minor_version(scratch_class->minor_version()); 4026 scratch_class->set_minor_version(old_minor_version); 4027 4028 // Replace major version number of class file 4029 u2 old_major_version = the_class->major_version(); 4030 the_class->set_major_version(scratch_class->major_version()); 4031 scratch_class->set_major_version(old_major_version); 4032 4033 // Replace CP indexes for class and name+type of enclosing method 4034 u2 old_class_idx = the_class->enclosing_method_class_index(); 4035 u2 old_method_idx = the_class->enclosing_method_method_index(); 4036 the_class->set_enclosing_method_indices( 4037 scratch_class->enclosing_method_class_index(), 4038 scratch_class->enclosing_method_method_index()); 4039 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx); 4040 4041 // Replace fingerprint data 4042 the_class->set_has_passed_fingerprint_check(scratch_class->has_passed_fingerprint_check()); 4043 the_class->store_fingerprint(scratch_class->get_stored_fingerprint()); 4044 4045 the_class->set_has_been_redefined(); 4046 4047 if (!the_class->should_be_initialized()) { 4048 // Class was already initialized, so AOT has only seen the original version. 4049 // We need to let AOT look at it again. 4050 AOTLoader::load_for_klass(the_class, THREAD); 4051 } 4052 4053 // keep track of previous versions of this class 4054 the_class->add_previous_version(scratch_class, emcp_method_count); 4055 4056 _timer_rsc_phase1.stop(); 4057 if (log_is_enabled(Info, redefine, class, timer)) { 4058 _timer_rsc_phase2.start(); 4059 } 4060 4061 // Adjust constantpool caches and vtables for all classes 4062 // that reference methods of the evolved class. 4063 AdjustCpoolCacheAndVtable adjust_cpool_cache_and_vtable(THREAD); 4064 ClassLoaderDataGraph::classes_do(&adjust_cpool_cache_and_vtable); 4065 4066 if (the_class->oop_map_cache() != NULL) { 4067 // Flush references to any obsolete methods from the oop map cache 4068 // so that obsolete methods are not pinned. 4069 the_class->oop_map_cache()->flush_obsolete_entries(); 4070 } 4071 4072 increment_class_counter((InstanceKlass *)the_class, THREAD); 4073 { 4074 ResourceMark rm(THREAD); 4075 // increment the classRedefinedCount field in the_class and in any 4076 // direct and indirect subclasses of the_class 4077 log_info(redefine, class, load) 4078 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)", 4079 the_class->external_name(), java_lang_Class::classRedefinedCount(the_class->java_mirror()), os::available_memory() >> 10); 4080 Events::log_redefinition(THREAD, "redefined class name=%s, count=%d", 4081 the_class->external_name(), 4082 java_lang_Class::classRedefinedCount(the_class->java_mirror())); 4083 4084 } 4085 _timer_rsc_phase2.stop(); 4086 } // end redefine_single_class() 4087 4088 4089 // Increment the classRedefinedCount field in the specific InstanceKlass 4090 // and in all direct and indirect subclasses. 4091 void VM_RedefineClasses::increment_class_counter(InstanceKlass *ik, TRAPS) { 4092 oop class_mirror = ik->java_mirror(); 4093 Klass* class_oop = java_lang_Class::as_Klass(class_mirror); 4094 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1; 4095 java_lang_Class::set_classRedefinedCount(class_mirror, new_count); 4096 4097 if (class_oop != _the_class) { 4098 // _the_class count is printed at end of redefine_single_class() 4099 log_debug(redefine, class, subclass)("updated count in subclass=%s to %d", ik->external_name(), new_count); 4100 } 4101 4102 for (Klass *subk = ik->subklass(); subk != NULL; 4103 subk = subk->next_sibling()) { 4104 if (subk->is_instance_klass()) { 4105 // Only update instanceKlasses 4106 InstanceKlass *subik = InstanceKlass::cast(subk); 4107 // recursively do subclasses of the current subclass 4108 increment_class_counter(subik, THREAD); 4109 } 4110 } 4111 } 4112 4113 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) { 4114 bool no_old_methods = true; // be optimistic 4115 4116 // Both array and instance classes have vtables. 4117 // a vtable should never contain old or obsolete methods 4118 ResourceMark rm(_thread); 4119 if (k->vtable_length() > 0 && 4120 !k->vtable().check_no_old_or_obsolete_entries()) { 4121 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 4122 log_trace(redefine, class, obsolete, metadata) 4123 ("klassVtable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s", 4124 k->signature_name()); 4125 k->vtable().dump_vtable(); 4126 } 4127 no_old_methods = false; 4128 } 4129 4130 if (k->is_instance_klass()) { 4131 HandleMark hm(_thread); 4132 InstanceKlass *ik = InstanceKlass::cast(k); 4133 4134 // an itable should never contain old or obsolete methods 4135 if (ik->itable_length() > 0 && 4136 !ik->itable().check_no_old_or_obsolete_entries()) { 4137 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 4138 log_trace(redefine, class, obsolete, metadata) 4139 ("klassItable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s", 4140 ik->signature_name()); 4141 ik->itable().dump_itable(); 4142 } 4143 no_old_methods = false; 4144 } 4145 4146 // the constant pool cache should never contain non-deleted old or obsolete methods 4147 if (ik->constants() != NULL && 4148 ik->constants()->cache() != NULL && 4149 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) { 4150 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 4151 log_trace(redefine, class, obsolete, metadata) 4152 ("cp-cache::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s", 4153 ik->signature_name()); 4154 ik->constants()->cache()->dump_cache(); 4155 } 4156 no_old_methods = false; 4157 } 4158 } 4159 4160 // print and fail guarantee if old methods are found. 4161 if (!no_old_methods) { 4162 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { 4163 dump_methods(); 4164 } else { 4165 log_trace(redefine, class)("Use the '-Xlog:redefine+class*:' option " 4166 "to see more info about the following guarantee() failure."); 4167 } 4168 guarantee(false, "OLD and/or OBSOLETE method(s) found"); 4169 } 4170 } 4171 4172 4173 void VM_RedefineClasses::dump_methods() { 4174 int j; 4175 log_trace(redefine, class, dump)("_old_methods --"); 4176 for (j = 0; j < _old_methods->length(); ++j) { 4177 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4178 Method* m = _old_methods->at(j); 4179 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4180 m->access_flags().print_on(&log_stream); 4181 log_stream.print(" -- "); 4182 m->print_name(&log_stream); 4183 log_stream.cr(); 4184 } 4185 log_trace(redefine, class, dump)("_new_methods --"); 4186 for (j = 0; j < _new_methods->length(); ++j) { 4187 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4188 Method* m = _new_methods->at(j); 4189 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4190 m->access_flags().print_on(&log_stream); 4191 log_stream.print(" -- "); 4192 m->print_name(&log_stream); 4193 log_stream.cr(); 4194 } 4195 log_trace(redefine, class, dump)("_matching_methods --"); 4196 for (j = 0; j < _matching_methods_length; ++j) { 4197 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4198 Method* m = _matching_old_methods[j]; 4199 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4200 m->access_flags().print_on(&log_stream); 4201 log_stream.print(" -- "); 4202 m->print_name(); 4203 log_stream.cr(); 4204 4205 m = _matching_new_methods[j]; 4206 log_stream.print(" (%5d) ", m->vtable_index()); 4207 m->access_flags().print_on(&log_stream); 4208 log_stream.cr(); 4209 } 4210 log_trace(redefine, class, dump)("_deleted_methods --"); 4211 for (j = 0; j < _deleted_methods_length; ++j) { 4212 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4213 Method* m = _deleted_methods[j]; 4214 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4215 m->access_flags().print_on(&log_stream); 4216 log_stream.print(" -- "); 4217 m->print_name(&log_stream); 4218 log_stream.cr(); 4219 } 4220 log_trace(redefine, class, dump)("_added_methods --"); 4221 for (j = 0; j < _added_methods_length; ++j) { 4222 LogStreamHandle(Trace, redefine, class, dump) log_stream; 4223 Method* m = _added_methods[j]; 4224 log_stream.print("%4d (%5d) ", j, m->vtable_index()); 4225 m->access_flags().print_on(&log_stream); 4226 log_stream.print(" -- "); 4227 m->print_name(&log_stream); 4228 log_stream.cr(); 4229 } 4230 } 4231 4232 void VM_RedefineClasses::print_on_error(outputStream* st) const { 4233 VM_Operation::print_on_error(st); 4234 if (_the_class != NULL) { 4235 ResourceMark rm; 4236 st->print_cr(", redefining class %s", _the_class->external_name()); 4237 } 4238 }