1 /* 2 * Copyright (c) 2003, 2015, 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 "classfile/metadataOnStackMark.hpp" 27 #include "classfile/systemDictionary.hpp" 28 #include "classfile/verifier.hpp" 29 #include "code/codeCache.hpp" 30 #include "compiler/compileBroker.hpp" 31 #include "interpreter/oopMapCache.hpp" 32 #include "interpreter/rewriter.hpp" 33 #include "memory/gcLocker.hpp" 34 #include "memory/metadataFactory.hpp" 35 #include "memory/metaspaceShared.hpp" 36 #include "memory/universe.inline.hpp" 37 #include "oops/fieldStreams.hpp" 38 #include "oops/klassVtable.hpp" 39 #include "oops/oop.inline.hpp" 40 #include "prims/jvmtiImpl.hpp" 41 #include "prims/jvmtiRedefineClasses.hpp" 42 #include "prims/methodComparator.hpp" 43 #include "runtime/deoptimization.hpp" 44 #include "runtime/relocator.hpp" 45 #include "utilities/bitMap.inline.hpp" 46 47 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC 48 49 Array<Method*>* VM_RedefineClasses::_old_methods = NULL; 50 Array<Method*>* VM_RedefineClasses::_new_methods = NULL; 51 Method** VM_RedefineClasses::_matching_old_methods = NULL; 52 Method** VM_RedefineClasses::_matching_new_methods = NULL; 53 Method** VM_RedefineClasses::_deleted_methods = NULL; 54 Method** VM_RedefineClasses::_added_methods = NULL; 55 int VM_RedefineClasses::_matching_methods_length = 0; 56 int VM_RedefineClasses::_deleted_methods_length = 0; 57 int VM_RedefineClasses::_added_methods_length = 0; 58 Klass* VM_RedefineClasses::_the_class_oop = NULL; 59 60 61 VM_RedefineClasses::VM_RedefineClasses(jint class_count, 62 const jvmtiClassDefinition *class_defs, 63 JvmtiClassLoadKind class_load_kind) { 64 _class_count = class_count; 65 _class_defs = class_defs; 66 _class_load_kind = class_load_kind; 67 _res = JVMTI_ERROR_NONE; 68 } 69 70 bool VM_RedefineClasses::doit_prologue() { 71 if (_class_count == 0) { 72 _res = JVMTI_ERROR_NONE; 73 return false; 74 } 75 if (_class_defs == NULL) { 76 _res = JVMTI_ERROR_NULL_POINTER; 77 return false; 78 } 79 for (int i = 0; i < _class_count; i++) { 80 if (_class_defs[i].klass == NULL) { 81 _res = JVMTI_ERROR_INVALID_CLASS; 82 return false; 83 } 84 if (_class_defs[i].class_byte_count == 0) { 85 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT; 86 return false; 87 } 88 if (_class_defs[i].class_bytes == NULL) { 89 _res = JVMTI_ERROR_NULL_POINTER; 90 return false; 91 } 92 } 93 94 // Start timer after all the sanity checks; not quite accurate, but 95 // better than adding a bunch of stop() calls. 96 RC_TIMER_START(_timer_vm_op_prologue); 97 98 // We first load new class versions in the prologue, because somewhere down the 99 // call chain it is required that the current thread is a Java thread. 100 _res = load_new_class_versions(Thread::current()); 101 if (_res != JVMTI_ERROR_NONE) { 102 // free any successfully created classes, since none are redefined 103 for (int i = 0; i < _class_count; i++) { 104 if (_scratch_classes[i] != NULL) { 105 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data(); 106 // Free the memory for this class at class unloading time. Not before 107 // because CMS might think this is still live. 108 cld->add_to_deallocate_list((InstanceKlass*)_scratch_classes[i]); 109 } 110 } 111 // Free os::malloc allocated memory in load_new_class_version. 112 os::free(_scratch_classes); 113 RC_TIMER_STOP(_timer_vm_op_prologue); 114 return false; 115 } 116 117 RC_TIMER_STOP(_timer_vm_op_prologue); 118 return true; 119 } 120 121 void VM_RedefineClasses::doit() { 122 Thread *thread = Thread::current(); 123 124 if (UseSharedSpaces) { 125 // Sharing is enabled so we remap the shared readonly space to 126 // shared readwrite, private just in case we need to redefine 127 // a shared class. We do the remap during the doit() phase of 128 // the safepoint to be safer. 129 if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) { 130 RC_TRACE_WITH_THREAD(0x00000001, thread, 131 ("failed to remap shared readonly space to readwrite, private")); 132 _res = JVMTI_ERROR_INTERNAL; 133 return; 134 } 135 } 136 137 // Mark methods seen on stack and everywhere else so old methods are not 138 // cleaned up if they're on the stack. 139 MetadataOnStackMark md_on_stack(true); 140 HandleMark hm(thread); // make sure any handles created are deleted 141 // before the stack walk again. 142 143 for (int i = 0; i < _class_count; i++) { 144 redefine_single_class(_class_defs[i].klass, _scratch_classes[i], thread); 145 } 146 147 // Clean out MethodData pointing to old Method* 148 // Have to do this after all classes are redefined and all methods that 149 // are redefined are marked as old. 150 MethodDataCleaner clean_weak_method_links; 151 ClassLoaderDataGraph::classes_do(&clean_weak_method_links); 152 153 // Disable any dependent concurrent compilations 154 SystemDictionary::notice_modification(); 155 156 // Set flag indicating that some invariants are no longer true. 157 // See jvmtiExport.hpp for detailed explanation. 158 JvmtiExport::set_has_redefined_a_class(); 159 160 // check_class() is optionally called for product bits, but is 161 // always called for non-product bits. 162 #ifdef PRODUCT 163 if (RC_TRACE_ENABLED(0x00004000)) { 164 #endif 165 RC_TRACE_WITH_THREAD(0x00004000, thread, ("calling check_class")); 166 CheckClass check_class(thread); 167 ClassLoaderDataGraph::classes_do(&check_class); 168 #ifdef PRODUCT 169 } 170 #endif 171 } 172 173 void VM_RedefineClasses::doit_epilogue() { 174 // Free os::malloc allocated memory. 175 os::free(_scratch_classes); 176 177 if (RC_TRACE_ENABLED(0x00000004)) { 178 // Used to have separate timers for "doit" and "all", but the timer 179 // overhead skewed the measurements. 180 jlong doit_time = _timer_rsc_phase1.milliseconds() + 181 _timer_rsc_phase2.milliseconds(); 182 jlong all_time = _timer_vm_op_prologue.milliseconds() + doit_time; 183 184 RC_TRACE(0x00000004, ("vm_op: all=" UINT64_FORMAT 185 " prologue=" UINT64_FORMAT " doit=" UINT64_FORMAT, all_time, 186 _timer_vm_op_prologue.milliseconds(), doit_time)); 187 RC_TRACE(0x00000004, 188 ("redefine_single_class: phase1=" UINT64_FORMAT " phase2=" UINT64_FORMAT, 189 _timer_rsc_phase1.milliseconds(), _timer_rsc_phase2.milliseconds())); 190 } 191 } 192 193 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) { 194 // classes for primitives cannot be redefined 195 if (java_lang_Class::is_primitive(klass_mirror)) { 196 return false; 197 } 198 Klass* the_class_oop = java_lang_Class::as_Klass(klass_mirror); 199 // classes for arrays cannot be redefined 200 if (the_class_oop == NULL || !the_class_oop->oop_is_instance()) { 201 return false; 202 } 203 return true; 204 } 205 206 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p 207 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For 208 // direct CP entries, there is just the current entry to append. For 209 // indirect and double-indirect CP entries, there are zero or more 210 // referenced CP entries along with the current entry to append. 211 // Indirect and double-indirect CP entries are handled by recursive 212 // calls to append_entry() as needed. The referenced CP entries are 213 // always appended to *merge_cp_p before the referee CP entry. These 214 // referenced CP entries may already exist in *merge_cp_p in which case 215 // there is nothing extra to append and only the current entry is 216 // appended. 217 void VM_RedefineClasses::append_entry(constantPoolHandle scratch_cp, 218 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, 219 TRAPS) { 220 221 // append is different depending on entry tag type 222 switch (scratch_cp->tag_at(scratch_i).value()) { 223 224 // The old verifier is implemented outside the VM. It loads classes, 225 // but does not resolve constant pool entries directly so we never 226 // see Class entries here with the old verifier. Similarly the old 227 // verifier does not like Class entries in the input constant pool. 228 // The split-verifier is implemented in the VM so it can optionally 229 // and directly resolve constant pool entries to load classes. The 230 // split-verifier can accept either Class entries or UnresolvedClass 231 // entries in the input constant pool. We revert the appended copy 232 // back to UnresolvedClass so that either verifier will be happy 233 // with the constant pool entry. 234 case JVM_CONSTANT_Class: 235 { 236 // revert the copy to JVM_CONSTANT_UnresolvedClass 237 (*merge_cp_p)->unresolved_klass_at_put(*merge_cp_length_p, 238 scratch_cp->klass_name_at(scratch_i)); 239 240 if (scratch_i != *merge_cp_length_p) { 241 // The new entry in *merge_cp_p is at a different index than 242 // the new entry in scratch_cp so we need to map the index values. 243 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 244 } 245 (*merge_cp_length_p)++; 246 } break; 247 248 // these are direct CP entries so they can be directly appended, 249 // but double and long take two constant pool entries 250 case JVM_CONSTANT_Double: // fall through 251 case JVM_CONSTANT_Long: 252 { 253 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p, 254 THREAD); 255 256 if (scratch_i != *merge_cp_length_p) { 257 // The new entry in *merge_cp_p is at a different index than 258 // the new entry in scratch_cp so we need to map the index values. 259 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 260 } 261 (*merge_cp_length_p) += 2; 262 } break; 263 264 // these are direct CP entries so they can be directly appended 265 case JVM_CONSTANT_Float: // fall through 266 case JVM_CONSTANT_Integer: // fall through 267 case JVM_CONSTANT_Utf8: // fall through 268 269 // This was an indirect CP entry, but it has been changed into 270 // Symbol*s so this entry can be directly appended. 271 case JVM_CONSTANT_String: // fall through 272 273 // These were indirect CP entries, but they have been changed into 274 // Symbol*s so these entries can be directly appended. 275 case JVM_CONSTANT_UnresolvedClass: // fall through 276 { 277 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p, 278 THREAD); 279 280 if (scratch_i != *merge_cp_length_p) { 281 // The new entry in *merge_cp_p is at a different index than 282 // the new entry in scratch_cp so we need to map the index values. 283 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 284 } 285 (*merge_cp_length_p)++; 286 } break; 287 288 // this is an indirect CP entry so it needs special handling 289 case JVM_CONSTANT_NameAndType: 290 { 291 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i); 292 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p, 293 merge_cp_length_p, THREAD); 294 295 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i); 296 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i, 297 merge_cp_p, merge_cp_length_p, 298 THREAD); 299 300 // If the referenced entries already exist in *merge_cp_p, then 301 // both new_name_ref_i and new_signature_ref_i will both be 0. 302 // In that case, all we are appending is the current entry. 303 if (new_name_ref_i != name_ref_i) { 304 RC_TRACE(0x00080000, 305 ("NameAndType entry@%d name_ref_index change: %d to %d", 306 *merge_cp_length_p, name_ref_i, new_name_ref_i)); 307 } 308 if (new_signature_ref_i != signature_ref_i) { 309 RC_TRACE(0x00080000, 310 ("NameAndType entry@%d signature_ref_index change: %d to %d", 311 *merge_cp_length_p, signature_ref_i, new_signature_ref_i)); 312 } 313 314 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p, 315 new_name_ref_i, new_signature_ref_i); 316 if (scratch_i != *merge_cp_length_p) { 317 // The new entry in *merge_cp_p is at a different index than 318 // the new entry in scratch_cp so we need to map the index values. 319 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 320 } 321 (*merge_cp_length_p)++; 322 } break; 323 324 // this is a double-indirect CP entry so it needs special handling 325 case JVM_CONSTANT_Fieldref: // fall through 326 case JVM_CONSTANT_InterfaceMethodref: // fall through 327 case JVM_CONSTANT_Methodref: 328 { 329 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i); 330 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i, 331 merge_cp_p, merge_cp_length_p, THREAD); 332 333 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i); 334 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i, 335 merge_cp_p, merge_cp_length_p, THREAD); 336 337 const char *entry_name; 338 switch (scratch_cp->tag_at(scratch_i).value()) { 339 case JVM_CONSTANT_Fieldref: 340 entry_name = "Fieldref"; 341 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i, 342 new_name_and_type_ref_i); 343 break; 344 case JVM_CONSTANT_InterfaceMethodref: 345 entry_name = "IFMethodref"; 346 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p, 347 new_klass_ref_i, new_name_and_type_ref_i); 348 break; 349 case JVM_CONSTANT_Methodref: 350 entry_name = "Methodref"; 351 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i, 352 new_name_and_type_ref_i); 353 break; 354 default: 355 guarantee(false, "bad switch"); 356 break; 357 } 358 359 if (klass_ref_i != new_klass_ref_i) { 360 RC_TRACE(0x00080000, ("%s entry@%d class_index changed: %d to %d", 361 entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i)); 362 } 363 if (name_and_type_ref_i != new_name_and_type_ref_i) { 364 RC_TRACE(0x00080000, 365 ("%s entry@%d name_and_type_index changed: %d to %d", 366 entry_name, *merge_cp_length_p, name_and_type_ref_i, 367 new_name_and_type_ref_i)); 368 } 369 370 if (scratch_i != *merge_cp_length_p) { 371 // The new entry in *merge_cp_p is at a different index than 372 // the new entry in scratch_cp so we need to map the index values. 373 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 374 } 375 (*merge_cp_length_p)++; 376 } break; 377 378 // this is an indirect CP entry so it needs special handling 379 case JVM_CONSTANT_MethodType: 380 { 381 int ref_i = scratch_cp->method_type_index_at(scratch_i); 382 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p, 383 merge_cp_length_p, THREAD); 384 if (new_ref_i != ref_i) { 385 RC_TRACE(0x00080000, 386 ("MethodType entry@%d ref_index change: %d to %d", 387 *merge_cp_length_p, ref_i, new_ref_i)); 388 } 389 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i); 390 if (scratch_i != *merge_cp_length_p) { 391 // The new entry in *merge_cp_p is at a different index than 392 // the new entry in scratch_cp so we need to map the index values. 393 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 394 } 395 (*merge_cp_length_p)++; 396 } break; 397 398 // this is an indirect CP entry so it needs special handling 399 case JVM_CONSTANT_MethodHandle: 400 { 401 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i); 402 int ref_i = scratch_cp->method_handle_index_at(scratch_i); 403 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p, 404 merge_cp_length_p, THREAD); 405 if (new_ref_i != ref_i) { 406 RC_TRACE(0x00080000, 407 ("MethodHandle entry@%d ref_index change: %d to %d", 408 *merge_cp_length_p, ref_i, new_ref_i)); 409 } 410 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i); 411 if (scratch_i != *merge_cp_length_p) { 412 // The new entry in *merge_cp_p is at a different index than 413 // the new entry in scratch_cp so we need to map the index values. 414 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 415 } 416 (*merge_cp_length_p)++; 417 } break; 418 419 // this is an indirect CP entry so it needs special handling 420 case JVM_CONSTANT_InvokeDynamic: 421 { 422 // Index of the bootstrap specifier in the operands array 423 int old_bs_i = scratch_cp->invoke_dynamic_bootstrap_specifier_index(scratch_i); 424 int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p, 425 merge_cp_length_p, THREAD); 426 // The bootstrap method NameAndType_info index 427 int old_ref_i = scratch_cp->invoke_dynamic_name_and_type_ref_index_at(scratch_i); 428 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p, 429 merge_cp_length_p, THREAD); 430 if (new_bs_i != old_bs_i) { 431 RC_TRACE(0x00080000, 432 ("InvokeDynamic entry@%d bootstrap_method_attr_index change: %d to %d", 433 *merge_cp_length_p, old_bs_i, new_bs_i)); 434 } 435 if (new_ref_i != old_ref_i) { 436 RC_TRACE(0x00080000, 437 ("InvokeDynamic entry@%d name_and_type_index change: %d to %d", 438 *merge_cp_length_p, old_ref_i, new_ref_i)); 439 } 440 441 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i); 442 if (scratch_i != *merge_cp_length_p) { 443 // The new entry in *merge_cp_p is at a different index than 444 // the new entry in scratch_cp so we need to map the index values. 445 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 446 } 447 (*merge_cp_length_p)++; 448 } break; 449 450 // At this stage, Class or UnresolvedClass could be here, but not 451 // ClassIndex 452 case JVM_CONSTANT_ClassIndex: // fall through 453 454 // Invalid is used as the tag for the second constant pool entry 455 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should 456 // not be seen by itself. 457 case JVM_CONSTANT_Invalid: // fall through 458 459 // At this stage, String could be here, but not StringIndex 460 case JVM_CONSTANT_StringIndex: // fall through 461 462 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be 463 // here 464 case JVM_CONSTANT_UnresolvedClassInError: // fall through 465 466 default: 467 { 468 // leave a breadcrumb 469 jbyte bad_value = scratch_cp->tag_at(scratch_i).value(); 470 ShouldNotReachHere(); 471 } break; 472 } // end switch tag value 473 } // end append_entry() 474 475 476 int VM_RedefineClasses::find_or_append_indirect_entry(constantPoolHandle scratch_cp, 477 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) { 478 479 int new_ref_i = ref_i; 480 bool match = (ref_i < *merge_cp_length_p) && 481 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i, THREAD); 482 483 if (!match) { 484 // forward reference in *merge_cp_p or not a direct match 485 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p, THREAD); 486 if (found_i != 0) { 487 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree"); 488 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry. 489 new_ref_i = found_i; 490 map_index(scratch_cp, ref_i, found_i); 491 } else { 492 // no match found so we have to append this entry to *merge_cp_p 493 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p, THREAD); 494 // The above call to append_entry() can only append one entry 495 // so the post call query of *merge_cp_length_p is only for 496 // the sake of consistency. 497 new_ref_i = *merge_cp_length_p - 1; 498 } 499 } 500 501 return new_ref_i; 502 } // end find_or_append_indirect_entry() 503 504 505 // Append a bootstrap specifier into the merge_cp operands that is semantically equal 506 // to the scratch_cp operands bootstrap specifier passed by the old_bs_i index. 507 // Recursively append new merge_cp entries referenced by the new bootstrap specifier. 508 void VM_RedefineClasses::append_operand(constantPoolHandle scratch_cp, int old_bs_i, 509 constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) { 510 511 int old_ref_i = scratch_cp->operand_bootstrap_method_ref_index_at(old_bs_i); 512 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p, 513 merge_cp_length_p, THREAD); 514 if (new_ref_i != old_ref_i) { 515 RC_TRACE(0x00080000, 516 ("operands entry@%d bootstrap method ref_index change: %d to %d", 517 _operands_cur_length, old_ref_i, new_ref_i)); 518 } 519 520 Array<u2>* merge_ops = (*merge_cp_p)->operands(); 521 int new_bs_i = _operands_cur_length; 522 // We have _operands_cur_length == 0 when the merge_cp operands is empty yet. 523 // However, the operand_offset_at(0) was set in the extend_operands() call. 524 int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0) 525 : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1); 526 int argc = scratch_cp->operand_argument_count_at(old_bs_i); 527 528 ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base); 529 merge_ops->at_put(new_base++, new_ref_i); 530 merge_ops->at_put(new_base++, argc); 531 532 for (int i = 0; i < argc; i++) { 533 int old_arg_ref_i = scratch_cp->operand_argument_index_at(old_bs_i, i); 534 int new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p, 535 merge_cp_length_p, THREAD); 536 merge_ops->at_put(new_base++, new_arg_ref_i); 537 if (new_arg_ref_i != old_arg_ref_i) { 538 RC_TRACE(0x00080000, 539 ("operands entry@%d bootstrap method argument ref_index change: %d to %d", 540 _operands_cur_length, old_arg_ref_i, new_arg_ref_i)); 541 } 542 } 543 if (old_bs_i != _operands_cur_length) { 544 // The bootstrap specifier in *merge_cp_p is at a different index than 545 // that in scratch_cp so we need to map the index values. 546 map_operand_index(old_bs_i, new_bs_i); 547 } 548 _operands_cur_length++; 549 } // end append_operand() 550 551 552 int VM_RedefineClasses::find_or_append_operand(constantPoolHandle scratch_cp, 553 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) { 554 555 int new_bs_i = old_bs_i; // bootstrap specifier index 556 bool match = (old_bs_i < _operands_cur_length) && 557 scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i, THREAD); 558 559 if (!match) { 560 // forward reference in *merge_cp_p or not a direct match 561 int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p, 562 _operands_cur_length, THREAD); 563 if (found_i != -1) { 564 guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree"); 565 // found a matching operand somewhere else in *merge_cp_p so just need a mapping 566 new_bs_i = found_i; 567 map_operand_index(old_bs_i, found_i); 568 } else { 569 // no match found so we have to append this bootstrap specifier to *merge_cp_p 570 append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p, THREAD); 571 new_bs_i = _operands_cur_length - 1; 572 } 573 } 574 return new_bs_i; 575 } // end find_or_append_operand() 576 577 578 void VM_RedefineClasses::finalize_operands_merge(constantPoolHandle merge_cp, TRAPS) { 579 if (merge_cp->operands() == NULL) { 580 return; 581 } 582 // Shrink the merge_cp operands 583 merge_cp->shrink_operands(_operands_cur_length, CHECK); 584 585 if (RC_TRACE_ENABLED(0x00040000)) { 586 // don't want to loop unless we are tracing 587 int count = 0; 588 for (int i = 1; i < _operands_index_map_p->length(); i++) { 589 int value = _operands_index_map_p->at(i); 590 if (value != -1) { 591 RC_TRACE_WITH_THREAD(0x00040000, THREAD, 592 ("operands_index_map[%d]: old=%d new=%d", count, i, value)); 593 count++; 594 } 595 } 596 } 597 // Clean-up 598 _operands_index_map_p = NULL; 599 _operands_cur_length = 0; 600 _operands_index_map_count = 0; 601 } // end finalize_operands_merge() 602 603 604 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions( 605 instanceKlassHandle the_class, 606 instanceKlassHandle scratch_class) { 607 int i; 608 609 // Check superclasses, or rather their names, since superclasses themselves can be 610 // requested to replace. 611 // Check for NULL superclass first since this might be java.lang.Object 612 if (the_class->super() != scratch_class->super() && 613 (the_class->super() == NULL || scratch_class->super() == NULL || 614 the_class->super()->name() != 615 scratch_class->super()->name())) { 616 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 617 } 618 619 // Check if the number, names and order of directly implemented interfaces are the same. 620 // I think in principle we should just check if the sets of names of directly implemented 621 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the 622 // .java file, also changes in .class file) should not matter. However, comparing sets is 623 // technically a bit more difficult, and, more importantly, I am not sure at present that the 624 // order of interfaces does not matter on the implementation level, i.e. that the VM does not 625 // rely on it somewhere. 626 Array<Klass*>* k_interfaces = the_class->local_interfaces(); 627 Array<Klass*>* k_new_interfaces = scratch_class->local_interfaces(); 628 int n_intfs = k_interfaces->length(); 629 if (n_intfs != k_new_interfaces->length()) { 630 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 631 } 632 for (i = 0; i < n_intfs; i++) { 633 if (k_interfaces->at(i)->name() != 634 k_new_interfaces->at(i)->name()) { 635 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 636 } 637 } 638 639 // Check whether class is in the error init state. 640 if (the_class->is_in_error_state()) { 641 // TBD #5057930: special error code is needed in 1.6 642 return JVMTI_ERROR_INVALID_CLASS; 643 } 644 645 // Check whether class modifiers are the same. 646 jushort old_flags = (jushort) the_class->access_flags().get_flags(); 647 jushort new_flags = (jushort) scratch_class->access_flags().get_flags(); 648 if (old_flags != new_flags) { 649 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED; 650 } 651 652 // Check if the number, names, types and order of fields declared in these classes 653 // are the same. 654 JavaFieldStream old_fs(the_class); 655 JavaFieldStream new_fs(scratch_class); 656 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) { 657 // access 658 old_flags = old_fs.access_flags().as_short(); 659 new_flags = new_fs.access_flags().as_short(); 660 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) { 661 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 662 } 663 // offset 664 if (old_fs.offset() != new_fs.offset()) { 665 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 666 } 667 // name and signature 668 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index()); 669 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index()); 670 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index()); 671 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index()); 672 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) { 673 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 674 } 675 } 676 677 // If both streams aren't done then we have a differing number of 678 // fields. 679 if (!old_fs.done() || !new_fs.done()) { 680 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 681 } 682 683 // Do a parallel walk through the old and new methods. Detect 684 // cases where they match (exist in both), have been added in 685 // the new methods, or have been deleted (exist only in the 686 // old methods). The class file parser places methods in order 687 // by method name, but does not order overloaded methods by 688 // signature. In order to determine what fate befell the methods, 689 // this code places the overloaded new methods that have matching 690 // old methods in the same order as the old methods and places 691 // new overloaded methods at the end of overloaded methods of 692 // that name. The code for this order normalization is adapted 693 // from the algorithm used in InstanceKlass::find_method(). 694 // Since we are swapping out of order entries as we find them, 695 // we only have to search forward through the overloaded methods. 696 // Methods which are added and have the same name as an existing 697 // method (but different signature) will be put at the end of 698 // the methods with that name, and the name mismatch code will 699 // handle them. 700 Array<Method*>* k_old_methods(the_class->methods()); 701 Array<Method*>* k_new_methods(scratch_class->methods()); 702 int n_old_methods = k_old_methods->length(); 703 int n_new_methods = k_new_methods->length(); 704 Thread* thread = Thread::current(); 705 706 int ni = 0; 707 int oi = 0; 708 while (true) { 709 Method* k_old_method; 710 Method* k_new_method; 711 enum { matched, added, deleted, undetermined } method_was = undetermined; 712 713 if (oi >= n_old_methods) { 714 if (ni >= n_new_methods) { 715 break; // we've looked at everything, done 716 } 717 // New method at the end 718 k_new_method = k_new_methods->at(ni); 719 method_was = added; 720 } else if (ni >= n_new_methods) { 721 // Old method, at the end, is deleted 722 k_old_method = k_old_methods->at(oi); 723 method_was = deleted; 724 } else { 725 // There are more methods in both the old and new lists 726 k_old_method = k_old_methods->at(oi); 727 k_new_method = k_new_methods->at(ni); 728 if (k_old_method->name() != k_new_method->name()) { 729 // Methods are sorted by method name, so a mismatch means added 730 // or deleted 731 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) { 732 method_was = added; 733 } else { 734 method_was = deleted; 735 } 736 } else if (k_old_method->signature() == k_new_method->signature()) { 737 // Both the name and signature match 738 method_was = matched; 739 } else { 740 // The name matches, but the signature doesn't, which means we have to 741 // search forward through the new overloaded methods. 742 int nj; // outside the loop for post-loop check 743 for (nj = ni + 1; nj < n_new_methods; nj++) { 744 Method* m = k_new_methods->at(nj); 745 if (k_old_method->name() != m->name()) { 746 // reached another method name so no more overloaded methods 747 method_was = deleted; 748 break; 749 } 750 if (k_old_method->signature() == m->signature()) { 751 // found a match so swap the methods 752 k_new_methods->at_put(ni, m); 753 k_new_methods->at_put(nj, k_new_method); 754 k_new_method = m; 755 method_was = matched; 756 break; 757 } 758 } 759 760 if (nj >= n_new_methods) { 761 // reached the end without a match; so method was deleted 762 method_was = deleted; 763 } 764 } 765 } 766 767 switch (method_was) { 768 case matched: 769 // methods match, be sure modifiers do too 770 old_flags = (jushort) k_old_method->access_flags().get_flags(); 771 new_flags = (jushort) k_new_method->access_flags().get_flags(); 772 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) { 773 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED; 774 } 775 { 776 u2 new_num = k_new_method->method_idnum(); 777 u2 old_num = k_old_method->method_idnum(); 778 if (new_num != old_num) { 779 Method* idnum_owner = scratch_class->method_with_idnum(old_num); 780 if (idnum_owner != NULL) { 781 // There is already a method assigned this idnum -- switch them 782 // Take current and original idnum from the new_method 783 idnum_owner->set_method_idnum(new_num); 784 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum()); 785 } 786 // Take current and original idnum from the old_method 787 k_new_method->set_method_idnum(old_num); 788 k_new_method->set_orig_method_idnum(k_old_method->orig_method_idnum()); 789 if (thread->has_pending_exception()) { 790 return JVMTI_ERROR_OUT_OF_MEMORY; 791 } 792 } 793 } 794 RC_TRACE(0x00008000, ("Method matched: new: %s [%d] == old: %s [%d]", 795 k_new_method->name_and_sig_as_C_string(), ni, 796 k_old_method->name_and_sig_as_C_string(), oi)); 797 // advance to next pair of methods 798 ++oi; 799 ++ni; 800 break; 801 case added: 802 // method added, see if it is OK 803 new_flags = (jushort) k_new_method->access_flags().get_flags(); 804 if ((new_flags & JVM_ACC_PRIVATE) == 0 805 // hack: private should be treated as final, but alas 806 || (new_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0 807 ) { 808 // new methods must be private 809 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED; 810 } 811 { 812 u2 num = the_class->next_method_idnum(); 813 if (num == ConstMethod::UNSET_IDNUM) { 814 // cannot add any more methods 815 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED; 816 } 817 u2 new_num = k_new_method->method_idnum(); 818 Method* idnum_owner = scratch_class->method_with_idnum(num); 819 if (idnum_owner != NULL) { 820 // There is already a method assigned this idnum -- switch them 821 // Take current and original idnum from the new_method 822 idnum_owner->set_method_idnum(new_num); 823 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum()); 824 } 825 k_new_method->set_method_idnum(num); 826 k_new_method->set_orig_method_idnum(num); 827 if (thread->has_pending_exception()) { 828 return JVMTI_ERROR_OUT_OF_MEMORY; 829 } 830 } 831 RC_TRACE(0x00008000, ("Method added: new: %s [%d]", 832 k_new_method->name_and_sig_as_C_string(), ni)); 833 ++ni; // advance to next new method 834 break; 835 case deleted: 836 // method deleted, see if it is OK 837 old_flags = (jushort) k_old_method->access_flags().get_flags(); 838 if ((old_flags & JVM_ACC_PRIVATE) == 0 839 // hack: private should be treated as final, but alas 840 || (old_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0 841 ) { 842 // deleted methods must be private 843 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED; 844 } 845 RC_TRACE(0x00008000, ("Method deleted: old: %s [%d]", 846 k_old_method->name_and_sig_as_C_string(), oi)); 847 ++oi; // advance to next old method 848 break; 849 default: 850 ShouldNotReachHere(); 851 } 852 } 853 854 return JVMTI_ERROR_NONE; 855 } 856 857 858 // Find new constant pool index value for old constant pool index value 859 // by seaching the index map. Returns zero (0) if there is no mapped 860 // value for the old constant pool index. 861 int VM_RedefineClasses::find_new_index(int old_index) { 862 if (_index_map_count == 0) { 863 // map is empty so nothing can be found 864 return 0; 865 } 866 867 if (old_index < 1 || old_index >= _index_map_p->length()) { 868 // The old_index is out of range so it is not mapped. This should 869 // not happen in regular constant pool merging use, but it can 870 // happen if a corrupt annotation is processed. 871 return 0; 872 } 873 874 int value = _index_map_p->at(old_index); 875 if (value == -1) { 876 // the old_index is not mapped 877 return 0; 878 } 879 880 return value; 881 } // end find_new_index() 882 883 884 // Find new bootstrap specifier index value for old bootstrap specifier index 885 // value by seaching the index map. Returns unused index (-1) if there is 886 // no mapped value for the old bootstrap specifier index. 887 int VM_RedefineClasses::find_new_operand_index(int old_index) { 888 if (_operands_index_map_count == 0) { 889 // map is empty so nothing can be found 890 return -1; 891 } 892 893 if (old_index == -1 || old_index >= _operands_index_map_p->length()) { 894 // The old_index is out of range so it is not mapped. 895 // This should not happen in regular constant pool merging use. 896 return -1; 897 } 898 899 int value = _operands_index_map_p->at(old_index); 900 if (value == -1) { 901 // the old_index is not mapped 902 return -1; 903 } 904 905 return value; 906 } // end find_new_operand_index() 907 908 909 // Returns true if the current mismatch is due to a resolved/unresolved 910 // class pair. Otherwise, returns false. 911 bool VM_RedefineClasses::is_unresolved_class_mismatch(constantPoolHandle cp1, 912 int index1, constantPoolHandle cp2, int index2) { 913 914 jbyte t1 = cp1->tag_at(index1).value(); 915 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) { 916 return false; // wrong entry type; not our special case 917 } 918 919 jbyte t2 = cp2->tag_at(index2).value(); 920 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) { 921 return false; // wrong entry type; not our special case 922 } 923 924 if (t1 == t2) { 925 return false; // not a mismatch; not our special case 926 } 927 928 char *s1 = cp1->klass_name_at(index1)->as_C_string(); 929 char *s2 = cp2->klass_name_at(index2)->as_C_string(); 930 if (strcmp(s1, s2) != 0) { 931 return false; // strings don't match; not our special case 932 } 933 934 return true; // made it through the gauntlet; this is our special case 935 } // end is_unresolved_class_mismatch() 936 937 938 jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) { 939 940 // For consistency allocate memory using os::malloc wrapper. 941 _scratch_classes = (Klass**) 942 os::malloc(sizeof(Klass*) * _class_count, mtClass); 943 if (_scratch_classes == NULL) { 944 return JVMTI_ERROR_OUT_OF_MEMORY; 945 } 946 // Zero initialize the _scratch_classes array. 947 for (int i = 0; i < _class_count; i++) { 948 _scratch_classes[i] = NULL; 949 } 950 951 ResourceMark rm(THREAD); 952 953 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current()); 954 // state can only be NULL if the current thread is exiting which 955 // should not happen since we're trying to do a RedefineClasses 956 guarantee(state != NULL, "exiting thread calling load_new_class_versions"); 957 for (int i = 0; i < _class_count; i++) { 958 // Create HandleMark so that any handles created while loading new class 959 // versions are deleted. Constant pools are deallocated while merging 960 // constant pools 961 HandleMark hm(THREAD); 962 963 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass); 964 // classes for primitives cannot be redefined 965 if (!is_modifiable_class(mirror)) { 966 return JVMTI_ERROR_UNMODIFIABLE_CLASS; 967 } 968 Klass* the_class_oop = java_lang_Class::as_Klass(mirror); 969 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop); 970 Symbol* the_class_sym = the_class->name(); 971 972 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 973 RC_TRACE_WITH_THREAD(0x00000001, THREAD, 974 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)", 975 the_class->external_name(), _class_load_kind, 976 os::available_memory() >> 10)); 977 978 ClassFileStream st((u1*) _class_defs[i].class_bytes, 979 _class_defs[i].class_byte_count, (char *)"__VM_RedefineClasses__"); 980 981 // Parse the stream. 982 Handle the_class_loader(THREAD, the_class->class_loader()); 983 Handle protection_domain(THREAD, the_class->protection_domain()); 984 // Set redefined class handle in JvmtiThreadState class. 985 // This redefined class is sent to agent event handler for class file 986 // load hook event. 987 state->set_class_being_redefined(&the_class, _class_load_kind); 988 989 Klass* k = SystemDictionary::parse_stream(the_class_sym, 990 the_class_loader, 991 protection_domain, 992 &st, 993 THREAD); 994 // Clear class_being_redefined just to be sure. 995 state->clear_class_being_redefined(); 996 997 // TODO: if this is retransform, and nothing changed we can skip it 998 999 instanceKlassHandle scratch_class (THREAD, k); 1000 1001 // Need to clean up allocated InstanceKlass if there's an error so assign 1002 // the result here. Caller deallocates all the scratch classes in case of 1003 // an error. 1004 _scratch_classes[i] = k; 1005 1006 if (HAS_PENDING_EXCEPTION) { 1007 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1008 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1009 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("parse_stream exception: '%s'", 1010 ex_name->as_C_string())); 1011 CLEAR_PENDING_EXCEPTION; 1012 1013 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) { 1014 return JVMTI_ERROR_UNSUPPORTED_VERSION; 1015 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) { 1016 return JVMTI_ERROR_INVALID_CLASS_FORMAT; 1017 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) { 1018 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION; 1019 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) { 1020 // The message will be "XXX (wrong name: YYY)" 1021 return JVMTI_ERROR_NAMES_DONT_MATCH; 1022 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1023 return JVMTI_ERROR_OUT_OF_MEMORY; 1024 } else { // Just in case more exceptions can be thrown.. 1025 return JVMTI_ERROR_FAILS_VERIFICATION; 1026 } 1027 } 1028 1029 // Ensure class is linked before redefine 1030 if (!the_class->is_linked()) { 1031 the_class->link_class(THREAD); 1032 if (HAS_PENDING_EXCEPTION) { 1033 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1034 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1035 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("link_class exception: '%s'", 1036 ex_name->as_C_string())); 1037 CLEAR_PENDING_EXCEPTION; 1038 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1039 return JVMTI_ERROR_OUT_OF_MEMORY; 1040 } else { 1041 return JVMTI_ERROR_INTERNAL; 1042 } 1043 } 1044 } 1045 1046 // Do the validity checks in compare_and_normalize_class_versions() 1047 // before verifying the byte codes. By doing these checks first, we 1048 // limit the number of functions that require redirection from 1049 // the_class to scratch_class. In particular, we don't have to 1050 // modify JNI GetSuperclass() and thus won't change its performance. 1051 jvmtiError res = compare_and_normalize_class_versions(the_class, 1052 scratch_class); 1053 if (res != JVMTI_ERROR_NONE) { 1054 return res; 1055 } 1056 1057 // verify what the caller passed us 1058 { 1059 // The bug 6214132 caused the verification to fail. 1060 // Information about the_class and scratch_class is temporarily 1061 // recorded into jvmtiThreadState. This data is used to redirect 1062 // the_class to scratch_class in the JVM_* functions called by the 1063 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed 1064 // description. 1065 RedefineVerifyMark rvm(&the_class, &scratch_class, state); 1066 Verifier::verify( 1067 scratch_class, Verifier::ThrowException, true, THREAD); 1068 } 1069 1070 if (HAS_PENDING_EXCEPTION) { 1071 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1072 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1073 RC_TRACE_WITH_THREAD(0x00000002, THREAD, 1074 ("verify_byte_codes exception: '%s'", ex_name->as_C_string())); 1075 CLEAR_PENDING_EXCEPTION; 1076 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1077 return JVMTI_ERROR_OUT_OF_MEMORY; 1078 } else { 1079 // tell the caller the bytecodes are bad 1080 return JVMTI_ERROR_FAILS_VERIFICATION; 1081 } 1082 } 1083 1084 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD); 1085 if (HAS_PENDING_EXCEPTION) { 1086 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1087 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1088 RC_TRACE_WITH_THREAD(0x00000002, THREAD, 1089 ("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string())); 1090 CLEAR_PENDING_EXCEPTION; 1091 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1092 return JVMTI_ERROR_OUT_OF_MEMORY; 1093 } else { 1094 return JVMTI_ERROR_INTERNAL; 1095 } 1096 } 1097 1098 if (VerifyMergedCPBytecodes) { 1099 // verify what we have done during constant pool merging 1100 { 1101 RedefineVerifyMark rvm(&the_class, &scratch_class, state); 1102 Verifier::verify(scratch_class, Verifier::ThrowException, true, THREAD); 1103 } 1104 1105 if (HAS_PENDING_EXCEPTION) { 1106 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1107 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1108 RC_TRACE_WITH_THREAD(0x00000002, THREAD, 1109 ("verify_byte_codes post merge-CP exception: '%s'", 1110 ex_name->as_C_string())); 1111 CLEAR_PENDING_EXCEPTION; 1112 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1113 return JVMTI_ERROR_OUT_OF_MEMORY; 1114 } else { 1115 // tell the caller that constant pool merging screwed up 1116 return JVMTI_ERROR_INTERNAL; 1117 } 1118 } 1119 } 1120 1121 Rewriter::rewrite(scratch_class, THREAD); 1122 if (!HAS_PENDING_EXCEPTION) { 1123 scratch_class->link_methods(THREAD); 1124 } 1125 if (HAS_PENDING_EXCEPTION) { 1126 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1127 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1128 RC_TRACE_WITH_THREAD(0x00000002, THREAD, 1129 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string())); 1130 CLEAR_PENDING_EXCEPTION; 1131 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1132 return JVMTI_ERROR_OUT_OF_MEMORY; 1133 } else { 1134 return JVMTI_ERROR_INTERNAL; 1135 } 1136 } 1137 1138 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1139 RC_TRACE_WITH_THREAD(0x00000001, THREAD, 1140 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)", 1141 the_class->external_name(), os::available_memory() >> 10)); 1142 } 1143 1144 return JVMTI_ERROR_NONE; 1145 } 1146 1147 1148 // Map old_index to new_index as needed. scratch_cp is only needed 1149 // for RC_TRACE() calls. 1150 void VM_RedefineClasses::map_index(constantPoolHandle scratch_cp, 1151 int old_index, int new_index) { 1152 if (find_new_index(old_index) != 0) { 1153 // old_index is already mapped 1154 return; 1155 } 1156 1157 if (old_index == new_index) { 1158 // no mapping is needed 1159 return; 1160 } 1161 1162 _index_map_p->at_put(old_index, new_index); 1163 _index_map_count++; 1164 1165 RC_TRACE(0x00040000, ("mapped tag %d at index %d to %d", 1166 scratch_cp->tag_at(old_index).value(), old_index, new_index)); 1167 } // end map_index() 1168 1169 1170 // Map old_index to new_index as needed. 1171 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) { 1172 if (find_new_operand_index(old_index) != -1) { 1173 // old_index is already mapped 1174 return; 1175 } 1176 1177 if (old_index == new_index) { 1178 // no mapping is needed 1179 return; 1180 } 1181 1182 _operands_index_map_p->at_put(old_index, new_index); 1183 _operands_index_map_count++; 1184 1185 RC_TRACE(0x00040000, ("mapped bootstrap specifier at index %d to %d", old_index, new_index)); 1186 } // end map_index() 1187 1188 1189 // Merge old_cp and scratch_cp and return the results of the merge via 1190 // merge_cp_p. The number of entries in *merge_cp_p is returned via 1191 // merge_cp_length_p. The entries in old_cp occupy the same locations 1192 // in *merge_cp_p. Also creates a map of indices from entries in 1193 // scratch_cp to the corresponding entry in *merge_cp_p. Index map 1194 // entries are only created for entries in scratch_cp that occupy a 1195 // different location in *merged_cp_p. 1196 bool VM_RedefineClasses::merge_constant_pools(constantPoolHandle old_cp, 1197 constantPoolHandle scratch_cp, constantPoolHandle *merge_cp_p, 1198 int *merge_cp_length_p, TRAPS) { 1199 1200 if (merge_cp_p == NULL) { 1201 assert(false, "caller must provide scratch constantPool"); 1202 return false; // robustness 1203 } 1204 if (merge_cp_length_p == NULL) { 1205 assert(false, "caller must provide scratch CP length"); 1206 return false; // robustness 1207 } 1208 // Worst case we need old_cp->length() + scratch_cp()->length(), 1209 // but the caller might be smart so make sure we have at least 1210 // the minimum. 1211 if ((*merge_cp_p)->length() < old_cp->length()) { 1212 assert(false, "merge area too small"); 1213 return false; // robustness 1214 } 1215 1216 RC_TRACE_WITH_THREAD(0x00010000, THREAD, 1217 ("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(), 1218 scratch_cp->length())); 1219 1220 { 1221 // Pass 0: 1222 // The old_cp is copied to *merge_cp_p; this means that any code 1223 // using old_cp does not have to change. This work looks like a 1224 // perfect fit for ConstantPool*::copy_cp_to(), but we need to 1225 // handle one special case: 1226 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass 1227 // This will make verification happy. 1228 1229 int old_i; // index into old_cp 1230 1231 // index zero (0) is not used in constantPools 1232 for (old_i = 1; old_i < old_cp->length(); old_i++) { 1233 // leave debugging crumb 1234 jbyte old_tag = old_cp->tag_at(old_i).value(); 1235 switch (old_tag) { 1236 case JVM_CONSTANT_Class: 1237 case JVM_CONSTANT_UnresolvedClass: 1238 // revert the copy to JVM_CONSTANT_UnresolvedClass 1239 // May be resolving while calling this so do the same for 1240 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition) 1241 (*merge_cp_p)->unresolved_klass_at_put(old_i, 1242 old_cp->klass_name_at(old_i)); 1243 break; 1244 1245 case JVM_CONSTANT_Double: 1246 case JVM_CONSTANT_Long: 1247 // just copy the entry to *merge_cp_p, but double and long take 1248 // two constant pool entries 1249 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0); 1250 old_i++; 1251 break; 1252 1253 default: 1254 // just copy the entry to *merge_cp_p 1255 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0); 1256 break; 1257 } 1258 } // end for each old_cp entry 1259 1260 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_0); 1261 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_0); 1262 1263 // We don't need to sanity check that *merge_cp_length_p is within 1264 // *merge_cp_p bounds since we have the minimum on-entry check above. 1265 (*merge_cp_length_p) = old_i; 1266 } 1267 1268 // merge_cp_len should be the same as old_cp->length() at this point 1269 // so this trace message is really a "warm-and-breathing" message. 1270 RC_TRACE_WITH_THREAD(0x00020000, THREAD, 1271 ("after pass 0: merge_cp_len=%d", *merge_cp_length_p)); 1272 1273 int scratch_i; // index into scratch_cp 1274 { 1275 // Pass 1a: 1276 // Compare scratch_cp entries to the old_cp entries that we have 1277 // already copied to *merge_cp_p. In this pass, we are eliminating 1278 // exact duplicates (matching entry at same index) so we only 1279 // compare entries in the common indice range. 1280 int increment = 1; 1281 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length()); 1282 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) { 1283 switch (scratch_cp->tag_at(scratch_i).value()) { 1284 case JVM_CONSTANT_Double: 1285 case JVM_CONSTANT_Long: 1286 // double and long take two constant pool entries 1287 increment = 2; 1288 break; 1289 1290 default: 1291 increment = 1; 1292 break; 1293 } 1294 1295 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p, 1296 scratch_i, CHECK_0); 1297 if (match) { 1298 // found a match at the same index so nothing more to do 1299 continue; 1300 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i, 1301 *merge_cp_p, scratch_i)) { 1302 // The mismatch in compare_entry_to() above is because of a 1303 // resolved versus unresolved class entry at the same index 1304 // with the same string value. Since Pass 0 reverted any 1305 // class entries to unresolved class entries in *merge_cp_p, 1306 // we go with the unresolved class entry. 1307 continue; 1308 } 1309 1310 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, 1311 CHECK_0); 1312 if (found_i != 0) { 1313 guarantee(found_i != scratch_i, 1314 "compare_entry_to() and find_matching_entry() do not agree"); 1315 1316 // Found a matching entry somewhere else in *merge_cp_p so 1317 // just need a mapping entry. 1318 map_index(scratch_cp, scratch_i, found_i); 1319 continue; 1320 } 1321 1322 // The find_matching_entry() call above could fail to find a match 1323 // due to a resolved versus unresolved class or string entry situation 1324 // like we solved above with the is_unresolved_*_mismatch() calls. 1325 // However, we would have to call is_unresolved_*_mismatch() over 1326 // all of *merge_cp_p (potentially) and that doesn't seem to be 1327 // worth the time. 1328 1329 // No match found so we have to append this entry and any unique 1330 // referenced entries to *merge_cp_p. 1331 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p, 1332 CHECK_0); 1333 } 1334 } 1335 1336 RC_TRACE_WITH_THREAD(0x00020000, THREAD, 1337 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", 1338 *merge_cp_length_p, scratch_i, _index_map_count)); 1339 1340 if (scratch_i < scratch_cp->length()) { 1341 // Pass 1b: 1342 // old_cp is smaller than scratch_cp so there are entries in 1343 // scratch_cp that we have not yet processed. We take care of 1344 // those now. 1345 int increment = 1; 1346 for (; scratch_i < scratch_cp->length(); scratch_i += increment) { 1347 switch (scratch_cp->tag_at(scratch_i).value()) { 1348 case JVM_CONSTANT_Double: 1349 case JVM_CONSTANT_Long: 1350 // double and long take two constant pool entries 1351 increment = 2; 1352 break; 1353 1354 default: 1355 increment = 1; 1356 break; 1357 } 1358 1359 int found_i = 1360 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0); 1361 if (found_i != 0) { 1362 // Found a matching entry somewhere else in *merge_cp_p so 1363 // just need a mapping entry. 1364 map_index(scratch_cp, scratch_i, found_i); 1365 continue; 1366 } 1367 1368 // No match found so we have to append this entry and any unique 1369 // referenced entries to *merge_cp_p. 1370 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p, 1371 CHECK_0); 1372 } 1373 1374 RC_TRACE_WITH_THREAD(0x00020000, THREAD, 1375 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", 1376 *merge_cp_length_p, scratch_i, _index_map_count)); 1377 } 1378 finalize_operands_merge(*merge_cp_p, THREAD); 1379 1380 return true; 1381 } // end merge_constant_pools() 1382 1383 1384 // Scoped object to clean up the constant pool(s) created for merging 1385 class MergeCPCleaner { 1386 ClassLoaderData* _loader_data; 1387 ConstantPool* _cp; 1388 ConstantPool* _scratch_cp; 1389 public: 1390 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) : 1391 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {} 1392 ~MergeCPCleaner() { 1393 _loader_data->add_to_deallocate_list(_cp); 1394 if (_scratch_cp != NULL) { 1395 _loader_data->add_to_deallocate_list(_scratch_cp); 1396 } 1397 } 1398 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; } 1399 }; 1400 1401 // Merge constant pools between the_class and scratch_class and 1402 // potentially rewrite bytecodes in scratch_class to use the merged 1403 // constant pool. 1404 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite( 1405 instanceKlassHandle the_class, instanceKlassHandle scratch_class, 1406 TRAPS) { 1407 // worst case merged constant pool length is old and new combined 1408 int merge_cp_length = the_class->constants()->length() 1409 + scratch_class->constants()->length(); 1410 1411 // Constant pools are not easily reused so we allocate a new one 1412 // each time. 1413 // merge_cp is created unsafe for concurrent GC processing. It 1414 // should be marked safe before discarding it. Even though 1415 // garbage, if it crosses a card boundary, it may be scanned 1416 // in order to find the start of the first complete object on the card. 1417 ClassLoaderData* loader_data = the_class->class_loader_data(); 1418 ConstantPool* merge_cp_oop = 1419 ConstantPool::allocate(loader_data, 1420 merge_cp_length, 1421 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1422 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop); 1423 1424 HandleMark hm(THREAD); // make sure handles are cleared before 1425 // MergeCPCleaner clears out merge_cp_oop 1426 constantPoolHandle merge_cp(THREAD, merge_cp_oop); 1427 1428 // Get constants() from the old class because it could have been rewritten 1429 // while we were at a safepoint allocating a new constant pool. 1430 constantPoolHandle old_cp(THREAD, the_class->constants()); 1431 constantPoolHandle scratch_cp(THREAD, scratch_class->constants()); 1432 1433 // If the length changed, the class was redefined out from under us. Return 1434 // an error. 1435 if (merge_cp_length != the_class->constants()->length() 1436 + scratch_class->constants()->length()) { 1437 return JVMTI_ERROR_INTERNAL; 1438 } 1439 1440 // Update the version number of the constant pool 1441 merge_cp->increment_and_save_version(old_cp->version()); 1442 1443 ResourceMark rm(THREAD); 1444 _index_map_count = 0; 1445 _index_map_p = new intArray(scratch_cp->length(), -1); 1446 1447 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands()); 1448 _operands_index_map_count = 0; 1449 _operands_index_map_p = new intArray( 1450 ConstantPool::operand_array_length(scratch_cp->operands()), -1); 1451 1452 // reference to the cp holder is needed for copy_operands() 1453 merge_cp->set_pool_holder(scratch_class()); 1454 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp, 1455 &merge_cp_length, THREAD); 1456 merge_cp->set_pool_holder(NULL); 1457 1458 if (!result) { 1459 // The merge can fail due to memory allocation failure or due 1460 // to robustness checks. 1461 return JVMTI_ERROR_INTERNAL; 1462 } 1463 1464 RC_TRACE_WITH_THREAD(0x00010000, THREAD, 1465 ("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count)); 1466 1467 if (_index_map_count == 0) { 1468 // there is nothing to map between the new and merged constant pools 1469 1470 if (old_cp->length() == scratch_cp->length()) { 1471 // The old and new constant pools are the same length and the 1472 // index map is empty. This means that the three constant pools 1473 // are equivalent (but not the same). Unfortunately, the new 1474 // constant pool has not gone through link resolution nor have 1475 // the new class bytecodes gone through constant pool cache 1476 // rewriting so we can't use the old constant pool with the new 1477 // class. 1478 1479 // toss the merged constant pool at return 1480 } else if (old_cp->length() < scratch_cp->length()) { 1481 // The old constant pool has fewer entries than the new constant 1482 // pool and the index map is empty. This means the new constant 1483 // pool is a superset of the old constant pool. However, the old 1484 // class bytecodes have already gone through constant pool cache 1485 // rewriting so we can't use the new constant pool with the old 1486 // class. 1487 1488 // toss the merged constant pool at return 1489 } else { 1490 // The old constant pool has more entries than the new constant 1491 // pool and the index map is empty. This means that both the old 1492 // and merged constant pools are supersets of the new constant 1493 // pool. 1494 1495 // Replace the new constant pool with a shrunken copy of the 1496 // merged constant pool 1497 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, 1498 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1499 // The new constant pool replaces scratch_cp so have cleaner clean it up. 1500 // It can't be cleaned up while there are handles to it. 1501 cp_cleaner.add_scratch_cp(scratch_cp()); 1502 } 1503 } else { 1504 if (RC_TRACE_ENABLED(0x00040000)) { 1505 // don't want to loop unless we are tracing 1506 int count = 0; 1507 for (int i = 1; i < _index_map_p->length(); i++) { 1508 int value = _index_map_p->at(i); 1509 1510 if (value != -1) { 1511 RC_TRACE_WITH_THREAD(0x00040000, THREAD, 1512 ("index_map[%d]: old=%d new=%d", count, i, value)); 1513 count++; 1514 } 1515 } 1516 } 1517 1518 // We have entries mapped between the new and merged constant pools 1519 // so we have to rewrite some constant pool references. 1520 if (!rewrite_cp_refs(scratch_class, THREAD)) { 1521 return JVMTI_ERROR_INTERNAL; 1522 } 1523 1524 // Replace the new constant pool with a shrunken copy of the 1525 // merged constant pool so now the rewritten bytecodes have 1526 // valid references; the previous new constant pool will get 1527 // GCed. 1528 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, 1529 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1530 // The new constant pool replaces scratch_cp so have cleaner clean it up. 1531 // It can't be cleaned up while there are handles to it. 1532 cp_cleaner.add_scratch_cp(scratch_cp()); 1533 } 1534 1535 return JVMTI_ERROR_NONE; 1536 } // end merge_cp_and_rewrite() 1537 1538 1539 // Rewrite constant pool references in klass scratch_class. 1540 bool VM_RedefineClasses::rewrite_cp_refs(instanceKlassHandle scratch_class, 1541 TRAPS) { 1542 1543 // rewrite constant pool references in the methods: 1544 if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) { 1545 // propagate failure back to caller 1546 return false; 1547 } 1548 1549 // rewrite constant pool references in the class_annotations: 1550 if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) { 1551 // propagate failure back to caller 1552 return false; 1553 } 1554 1555 // rewrite constant pool references in the fields_annotations: 1556 if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) { 1557 // propagate failure back to caller 1558 return false; 1559 } 1560 1561 // rewrite constant pool references in the methods_annotations: 1562 if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) { 1563 // propagate failure back to caller 1564 return false; 1565 } 1566 1567 // rewrite constant pool references in the methods_parameter_annotations: 1568 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class, 1569 THREAD)) { 1570 // propagate failure back to caller 1571 return false; 1572 } 1573 1574 // rewrite constant pool references in the methods_default_annotations: 1575 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class, 1576 THREAD)) { 1577 // propagate failure back to caller 1578 return false; 1579 } 1580 1581 // rewrite constant pool references in the class_type_annotations: 1582 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class, THREAD)) { 1583 // propagate failure back to caller 1584 return false; 1585 } 1586 1587 // rewrite constant pool references in the fields_type_annotations: 1588 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class, THREAD)) { 1589 // propagate failure back to caller 1590 return false; 1591 } 1592 1593 // rewrite constant pool references in the methods_type_annotations: 1594 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class, THREAD)) { 1595 // propagate failure back to caller 1596 return false; 1597 } 1598 1599 // There can be type annotations in the Code part of a method_info attribute. 1600 // These annotations are not accessible, even by reflection. 1601 // Currently they are not even parsed by the ClassFileParser. 1602 // If runtime access is added they will also need to be rewritten. 1603 1604 // rewrite source file name index: 1605 u2 source_file_name_idx = scratch_class->source_file_name_index(); 1606 if (source_file_name_idx != 0) { 1607 u2 new_source_file_name_idx = find_new_index(source_file_name_idx); 1608 if (new_source_file_name_idx != 0) { 1609 scratch_class->set_source_file_name_index(new_source_file_name_idx); 1610 } 1611 } 1612 1613 // rewrite class generic signature index: 1614 u2 generic_signature_index = scratch_class->generic_signature_index(); 1615 if (generic_signature_index != 0) { 1616 u2 new_generic_signature_index = find_new_index(generic_signature_index); 1617 if (new_generic_signature_index != 0) { 1618 scratch_class->set_generic_signature_index(new_generic_signature_index); 1619 } 1620 } 1621 1622 return true; 1623 } // end rewrite_cp_refs() 1624 1625 // Rewrite constant pool references in the methods. 1626 bool VM_RedefineClasses::rewrite_cp_refs_in_methods( 1627 instanceKlassHandle scratch_class, TRAPS) { 1628 1629 Array<Method*>* methods = scratch_class->methods(); 1630 1631 if (methods == NULL || methods->length() == 0) { 1632 // no methods so nothing to do 1633 return true; 1634 } 1635 1636 // rewrite constant pool references in the methods: 1637 for (int i = methods->length() - 1; i >= 0; i--) { 1638 methodHandle method(THREAD, methods->at(i)); 1639 methodHandle new_method; 1640 rewrite_cp_refs_in_method(method, &new_method, THREAD); 1641 if (!new_method.is_null()) { 1642 // the method has been replaced so save the new method version 1643 // even in the case of an exception. original method is on the 1644 // deallocation list. 1645 methods->at_put(i, new_method()); 1646 } 1647 if (HAS_PENDING_EXCEPTION) { 1648 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1649 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1650 RC_TRACE_WITH_THREAD(0x00000002, THREAD, 1651 ("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string())); 1652 // Need to clear pending exception here as the super caller sets 1653 // the JVMTI_ERROR_INTERNAL if the returned value is false. 1654 CLEAR_PENDING_EXCEPTION; 1655 return false; 1656 } 1657 } 1658 1659 return true; 1660 } 1661 1662 1663 // Rewrite constant pool references in the specific method. This code 1664 // was adapted from Rewriter::rewrite_method(). 1665 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method, 1666 methodHandle *new_method_p, TRAPS) { 1667 1668 *new_method_p = methodHandle(); // default is no new method 1669 1670 // We cache a pointer to the bytecodes here in code_base. If GC 1671 // moves the Method*, then the bytecodes will also move which 1672 // will likely cause a crash. We create a No_Safepoint_Verifier 1673 // object to detect whether we pass a possible safepoint in this 1674 // code block. 1675 No_Safepoint_Verifier nsv; 1676 1677 // Bytecodes and their length 1678 address code_base = method->code_base(); 1679 int code_length = method->code_size(); 1680 1681 int bc_length; 1682 for (int bci = 0; bci < code_length; bci += bc_length) { 1683 address bcp = code_base + bci; 1684 Bytecodes::Code c = (Bytecodes::Code)(*bcp); 1685 1686 bc_length = Bytecodes::length_for(c); 1687 if (bc_length == 0) { 1688 // More complicated bytecodes report a length of zero so 1689 // we have to try again a slightly different way. 1690 bc_length = Bytecodes::length_at(method(), bcp); 1691 } 1692 1693 assert(bc_length != 0, "impossible bytecode length"); 1694 1695 switch (c) { 1696 case Bytecodes::_ldc: 1697 { 1698 int cp_index = *(bcp + 1); 1699 int new_index = find_new_index(cp_index); 1700 1701 if (StressLdcRewrite && new_index == 0) { 1702 // If we are stressing ldc -> ldc_w rewriting, then we 1703 // always need a new_index value. 1704 new_index = cp_index; 1705 } 1706 if (new_index != 0) { 1707 // the original index is mapped so we have more work to do 1708 if (!StressLdcRewrite && new_index <= max_jubyte) { 1709 // The new value can still use ldc instead of ldc_w 1710 // unless we are trying to stress ldc -> ldc_w rewriting 1711 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 1712 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), 1713 bcp, cp_index, new_index)); 1714 *(bcp + 1) = new_index; 1715 } else { 1716 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 1717 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d", 1718 Bytecodes::name(c), bcp, cp_index, new_index)); 1719 // the new value needs ldc_w instead of ldc 1720 u_char inst_buffer[4]; // max instruction size is 4 bytes 1721 bcp = (address)inst_buffer; 1722 // construct new instruction sequence 1723 *bcp = Bytecodes::_ldc_w; 1724 bcp++; 1725 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w. 1726 // See comment below for difference between put_Java_u2() 1727 // and put_native_u2(). 1728 Bytes::put_Java_u2(bcp, new_index); 1729 1730 Relocator rc(method, NULL /* no RelocatorListener needed */); 1731 methodHandle m; 1732 { 1733 Pause_No_Safepoint_Verifier pnsv(&nsv); 1734 1735 // ldc is 2 bytes and ldc_w is 3 bytes 1736 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK); 1737 } 1738 1739 // return the new method so that the caller can update 1740 // the containing class 1741 *new_method_p = method = m; 1742 // switch our bytecode processing loop from the old method 1743 // to the new method 1744 code_base = method->code_base(); 1745 code_length = method->code_size(); 1746 bcp = code_base + bci; 1747 c = (Bytecodes::Code)(*bcp); 1748 bc_length = Bytecodes::length_for(c); 1749 assert(bc_length != 0, "sanity check"); 1750 } // end we need ldc_w instead of ldc 1751 } // end if there is a mapped index 1752 } break; 1753 1754 // these bytecodes have a two-byte constant pool index 1755 case Bytecodes::_anewarray : // fall through 1756 case Bytecodes::_checkcast : // fall through 1757 case Bytecodes::_getfield : // fall through 1758 case Bytecodes::_getstatic : // fall through 1759 case Bytecodes::_instanceof : // fall through 1760 case Bytecodes::_invokedynamic : // fall through 1761 case Bytecodes::_invokeinterface: // fall through 1762 case Bytecodes::_invokespecial : // fall through 1763 case Bytecodes::_invokestatic : // fall through 1764 case Bytecodes::_invokevirtual : // fall through 1765 case Bytecodes::_ldc_w : // fall through 1766 case Bytecodes::_ldc2_w : // fall through 1767 case Bytecodes::_multianewarray : // fall through 1768 case Bytecodes::_new : // fall through 1769 case Bytecodes::_putfield : // fall through 1770 case Bytecodes::_putstatic : 1771 { 1772 address p = bcp + 1; 1773 int cp_index = Bytes::get_Java_u2(p); 1774 int new_index = find_new_index(cp_index); 1775 if (new_index != 0) { 1776 // the original index is mapped so update w/ new value 1777 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 1778 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), 1779 bcp, cp_index, new_index)); 1780 // Rewriter::rewrite_method() uses put_native_u2() in this 1781 // situation because it is reusing the constant pool index 1782 // location for a native index into the ConstantPoolCache. 1783 // Since we are updating the constant pool index prior to 1784 // verification and ConstantPoolCache initialization, we 1785 // need to keep the new index in Java byte order. 1786 Bytes::put_Java_u2(p, new_index); 1787 } 1788 } break; 1789 } 1790 } // end for each bytecode 1791 1792 // We also need to rewrite the parameter name indexes, if there is 1793 // method parameter data present 1794 if(method->has_method_parameters()) { 1795 const int len = method->method_parameters_length(); 1796 MethodParametersElement* elem = method->method_parameters_start(); 1797 1798 for (int i = 0; i < len; i++) { 1799 const u2 cp_index = elem[i].name_cp_index; 1800 const u2 new_cp_index = find_new_index(cp_index); 1801 if (new_cp_index != 0) { 1802 elem[i].name_cp_index = new_cp_index; 1803 } 1804 } 1805 } 1806 } // end rewrite_cp_refs_in_method() 1807 1808 1809 // Rewrite constant pool references in the class_annotations field. 1810 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations( 1811 instanceKlassHandle scratch_class, TRAPS) { 1812 1813 AnnotationArray* class_annotations = scratch_class->class_annotations(); 1814 if (class_annotations == NULL || class_annotations->length() == 0) { 1815 // no class_annotations so nothing to do 1816 return true; 1817 } 1818 1819 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1820 ("class_annotations length=%d", class_annotations->length())); 1821 1822 int byte_i = 0; // byte index into class_annotations 1823 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i, 1824 THREAD); 1825 } 1826 1827 1828 // Rewrite constant pool references in an annotations typeArray. This 1829 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute 1830 // that is described in section 4.8.15 of the 2nd-edition of the VM spec: 1831 // 1832 // annotations_typeArray { 1833 // u2 num_annotations; 1834 // annotation annotations[num_annotations]; 1835 // } 1836 // 1837 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray( 1838 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) { 1839 1840 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 1841 // not enough room for num_annotations field 1842 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1843 ("length() is too small for num_annotations field")); 1844 return false; 1845 } 1846 1847 u2 num_annotations = Bytes::get_Java_u2((address) 1848 annotations_typeArray->adr_at(byte_i_ref)); 1849 byte_i_ref += 2; 1850 1851 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1852 ("num_annotations=%d", num_annotations)); 1853 1854 int calc_num_annotations = 0; 1855 for (; calc_num_annotations < num_annotations; calc_num_annotations++) { 1856 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, 1857 byte_i_ref, THREAD)) { 1858 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1859 ("bad annotation_struct at %d", calc_num_annotations)); 1860 // propagate failure back to caller 1861 return false; 1862 } 1863 } 1864 assert(num_annotations == calc_num_annotations, "sanity check"); 1865 1866 return true; 1867 } // end rewrite_cp_refs_in_annotations_typeArray() 1868 1869 1870 // Rewrite constant pool references in the annotation struct portion of 1871 // an annotations_typeArray. This "structure" is from section 4.8.15 of 1872 // the 2nd-edition of the VM spec: 1873 // 1874 // struct annotation { 1875 // u2 type_index; 1876 // u2 num_element_value_pairs; 1877 // { 1878 // u2 element_name_index; 1879 // element_value value; 1880 // } element_value_pairs[num_element_value_pairs]; 1881 // } 1882 // 1883 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct( 1884 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) { 1885 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) { 1886 // not enough room for smallest annotation_struct 1887 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1888 ("length() is too small for annotation_struct")); 1889 return false; 1890 } 1891 1892 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray, 1893 byte_i_ref, "mapped old type_index=%d", THREAD); 1894 1895 u2 num_element_value_pairs = Bytes::get_Java_u2((address) 1896 annotations_typeArray->adr_at(byte_i_ref)); 1897 byte_i_ref += 2; 1898 1899 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1900 ("type_index=%d num_element_value_pairs=%d", type_index, 1901 num_element_value_pairs)); 1902 1903 int calc_num_element_value_pairs = 0; 1904 for (; calc_num_element_value_pairs < num_element_value_pairs; 1905 calc_num_element_value_pairs++) { 1906 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 1907 // not enough room for another element_name_index, let alone 1908 // the rest of another component 1909 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1910 ("length() is too small for element_name_index")); 1911 return false; 1912 } 1913 1914 u2 element_name_index = rewrite_cp_ref_in_annotation_data( 1915 annotations_typeArray, byte_i_ref, 1916 "mapped old element_name_index=%d", THREAD); 1917 1918 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1919 ("element_name_index=%d", element_name_index)); 1920 1921 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, 1922 byte_i_ref, THREAD)) { 1923 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1924 ("bad element_value at %d", calc_num_element_value_pairs)); 1925 // propagate failure back to caller 1926 return false; 1927 } 1928 } // end for each component 1929 assert(num_element_value_pairs == calc_num_element_value_pairs, 1930 "sanity check"); 1931 1932 return true; 1933 } // end rewrite_cp_refs_in_annotation_struct() 1934 1935 1936 // Rewrite a constant pool reference at the current position in 1937 // annotations_typeArray if needed. Returns the original constant 1938 // pool reference if a rewrite was not needed or the new constant 1939 // pool reference if a rewrite was needed. 1940 PRAGMA_DIAG_PUSH 1941 PRAGMA_FORMAT_NONLITERAL_IGNORED 1942 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data( 1943 AnnotationArray* annotations_typeArray, int &byte_i_ref, 1944 const char * trace_mesg, TRAPS) { 1945 1946 address cp_index_addr = (address) 1947 annotations_typeArray->adr_at(byte_i_ref); 1948 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr); 1949 u2 new_cp_index = find_new_index(old_cp_index); 1950 if (new_cp_index != 0) { 1951 RC_TRACE_WITH_THREAD(0x02000000, THREAD, (trace_mesg, old_cp_index)); 1952 Bytes::put_Java_u2(cp_index_addr, new_cp_index); 1953 old_cp_index = new_cp_index; 1954 } 1955 byte_i_ref += 2; 1956 return old_cp_index; 1957 } 1958 PRAGMA_DIAG_POP 1959 1960 1961 // Rewrite constant pool references in the element_value portion of an 1962 // annotations_typeArray. This "structure" is from section 4.8.15.1 of 1963 // the 2nd-edition of the VM spec: 1964 // 1965 // struct element_value { 1966 // u1 tag; 1967 // union { 1968 // u2 const_value_index; 1969 // { 1970 // u2 type_name_index; 1971 // u2 const_name_index; 1972 // } enum_const_value; 1973 // u2 class_info_index; 1974 // annotation annotation_value; 1975 // struct { 1976 // u2 num_values; 1977 // element_value values[num_values]; 1978 // } array_value; 1979 // } value; 1980 // } 1981 // 1982 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value( 1983 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) { 1984 1985 if ((byte_i_ref + 1) > annotations_typeArray->length()) { 1986 // not enough room for a tag let alone the rest of an element_value 1987 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1988 ("length() is too small for a tag")); 1989 return false; 1990 } 1991 1992 u1 tag = annotations_typeArray->at(byte_i_ref); 1993 byte_i_ref++; 1994 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("tag='%c'", tag)); 1995 1996 switch (tag) { 1997 // These BaseType tag values are from Table 4.2 in VM spec: 1998 case 'B': // byte 1999 case 'C': // char 2000 case 'D': // double 2001 case 'F': // float 2002 case 'I': // int 2003 case 'J': // long 2004 case 'S': // short 2005 case 'Z': // boolean 2006 2007 // The remaining tag values are from Table 4.8 in the 2nd-edition of 2008 // the VM spec: 2009 case 's': 2010 { 2011 // For the above tag values (including the BaseType values), 2012 // value.const_value_index is right union field. 2013 2014 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2015 // not enough room for a const_value_index 2016 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2017 ("length() is too small for a const_value_index")); 2018 return false; 2019 } 2020 2021 u2 const_value_index = rewrite_cp_ref_in_annotation_data( 2022 annotations_typeArray, byte_i_ref, 2023 "mapped old const_value_index=%d", THREAD); 2024 2025 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2026 ("const_value_index=%d", const_value_index)); 2027 } break; 2028 2029 case 'e': 2030 { 2031 // for the above tag value, value.enum_const_value is right union field 2032 2033 if ((byte_i_ref + 4) > annotations_typeArray->length()) { 2034 // not enough room for a enum_const_value 2035 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2036 ("length() is too small for a enum_const_value")); 2037 return false; 2038 } 2039 2040 u2 type_name_index = rewrite_cp_ref_in_annotation_data( 2041 annotations_typeArray, byte_i_ref, 2042 "mapped old type_name_index=%d", THREAD); 2043 2044 u2 const_name_index = rewrite_cp_ref_in_annotation_data( 2045 annotations_typeArray, byte_i_ref, 2046 "mapped old const_name_index=%d", THREAD); 2047 2048 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2049 ("type_name_index=%d const_name_index=%d", type_name_index, 2050 const_name_index)); 2051 } break; 2052 2053 case 'c': 2054 { 2055 // for the above tag value, value.class_info_index is right union field 2056 2057 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2058 // not enough room for a class_info_index 2059 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2060 ("length() is too small for a class_info_index")); 2061 return false; 2062 } 2063 2064 u2 class_info_index = rewrite_cp_ref_in_annotation_data( 2065 annotations_typeArray, byte_i_ref, 2066 "mapped old class_info_index=%d", THREAD); 2067 2068 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2069 ("class_info_index=%d", class_info_index)); 2070 } break; 2071 2072 case '@': 2073 // For the above tag value, value.attr_value is the right union 2074 // field. This is a nested annotation. 2075 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, 2076 byte_i_ref, THREAD)) { 2077 // propagate failure back to caller 2078 return false; 2079 } 2080 break; 2081 2082 case '[': 2083 { 2084 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2085 // not enough room for a num_values field 2086 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2087 ("length() is too small for a num_values field")); 2088 return false; 2089 } 2090 2091 // For the above tag value, value.array_value is the right union 2092 // field. This is an array of nested element_value. 2093 u2 num_values = Bytes::get_Java_u2((address) 2094 annotations_typeArray->adr_at(byte_i_ref)); 2095 byte_i_ref += 2; 2096 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("num_values=%d", num_values)); 2097 2098 int calc_num_values = 0; 2099 for (; calc_num_values < num_values; calc_num_values++) { 2100 if (!rewrite_cp_refs_in_element_value( 2101 annotations_typeArray, byte_i_ref, THREAD)) { 2102 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2103 ("bad nested element_value at %d", calc_num_values)); 2104 // propagate failure back to caller 2105 return false; 2106 } 2107 } 2108 assert(num_values == calc_num_values, "sanity check"); 2109 } break; 2110 2111 default: 2112 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("bad tag=0x%x", tag)); 2113 return false; 2114 } // end decode tag field 2115 2116 return true; 2117 } // end rewrite_cp_refs_in_element_value() 2118 2119 2120 // Rewrite constant pool references in a fields_annotations field. 2121 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations( 2122 instanceKlassHandle scratch_class, TRAPS) { 2123 2124 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations(); 2125 2126 if (fields_annotations == NULL || fields_annotations->length() == 0) { 2127 // no fields_annotations so nothing to do 2128 return true; 2129 } 2130 2131 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2132 ("fields_annotations length=%d", fields_annotations->length())); 2133 2134 for (int i = 0; i < fields_annotations->length(); i++) { 2135 AnnotationArray* field_annotations = fields_annotations->at(i); 2136 if (field_annotations == NULL || field_annotations->length() == 0) { 2137 // this field does not have any annotations so skip it 2138 continue; 2139 } 2140 2141 int byte_i = 0; // byte index into field_annotations 2142 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i, 2143 THREAD)) { 2144 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2145 ("bad field_annotations at %d", i)); 2146 // propagate failure back to caller 2147 return false; 2148 } 2149 } 2150 2151 return true; 2152 } // end rewrite_cp_refs_in_fields_annotations() 2153 2154 2155 // Rewrite constant pool references in a methods_annotations field. 2156 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations( 2157 instanceKlassHandle scratch_class, TRAPS) { 2158 2159 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2160 Method* m = scratch_class->methods()->at(i); 2161 AnnotationArray* method_annotations = m->constMethod()->method_annotations(); 2162 2163 if (method_annotations == NULL || method_annotations->length() == 0) { 2164 // this method does not have any annotations so skip it 2165 continue; 2166 } 2167 2168 int byte_i = 0; // byte index into method_annotations 2169 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i, 2170 THREAD)) { 2171 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2172 ("bad method_annotations at %d", i)); 2173 // propagate failure back to caller 2174 return false; 2175 } 2176 } 2177 2178 return true; 2179 } // end rewrite_cp_refs_in_methods_annotations() 2180 2181 2182 // Rewrite constant pool references in a methods_parameter_annotations 2183 // field. This "structure" is adapted from the 2184 // RuntimeVisibleParameterAnnotations_attribute described in section 2185 // 4.8.17 of the 2nd-edition of the VM spec: 2186 // 2187 // methods_parameter_annotations_typeArray { 2188 // u1 num_parameters; 2189 // { 2190 // u2 num_annotations; 2191 // annotation annotations[num_annotations]; 2192 // } parameter_annotations[num_parameters]; 2193 // } 2194 // 2195 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations( 2196 instanceKlassHandle scratch_class, TRAPS) { 2197 2198 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2199 Method* m = scratch_class->methods()->at(i); 2200 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations(); 2201 if (method_parameter_annotations == NULL 2202 || method_parameter_annotations->length() == 0) { 2203 // this method does not have any parameter annotations so skip it 2204 continue; 2205 } 2206 2207 if (method_parameter_annotations->length() < 1) { 2208 // not enough room for a num_parameters field 2209 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2210 ("length() is too small for a num_parameters field at %d", i)); 2211 return false; 2212 } 2213 2214 int byte_i = 0; // byte index into method_parameter_annotations 2215 2216 u1 num_parameters = method_parameter_annotations->at(byte_i); 2217 byte_i++; 2218 2219 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2220 ("num_parameters=%d", num_parameters)); 2221 2222 int calc_num_parameters = 0; 2223 for (; calc_num_parameters < num_parameters; calc_num_parameters++) { 2224 if (!rewrite_cp_refs_in_annotations_typeArray( 2225 method_parameter_annotations, byte_i, THREAD)) { 2226 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2227 ("bad method_parameter_annotations at %d", calc_num_parameters)); 2228 // propagate failure back to caller 2229 return false; 2230 } 2231 } 2232 assert(num_parameters == calc_num_parameters, "sanity check"); 2233 } 2234 2235 return true; 2236 } // end rewrite_cp_refs_in_methods_parameter_annotations() 2237 2238 2239 // Rewrite constant pool references in a methods_default_annotations 2240 // field. This "structure" is adapted from the AnnotationDefault_attribute 2241 // that is described in section 4.8.19 of the 2nd-edition of the VM spec: 2242 // 2243 // methods_default_annotations_typeArray { 2244 // element_value default_value; 2245 // } 2246 // 2247 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations( 2248 instanceKlassHandle scratch_class, TRAPS) { 2249 2250 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2251 Method* m = scratch_class->methods()->at(i); 2252 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations(); 2253 if (method_default_annotations == NULL 2254 || method_default_annotations->length() == 0) { 2255 // this method does not have any default annotations so skip it 2256 continue; 2257 } 2258 2259 int byte_i = 0; // byte index into method_default_annotations 2260 2261 if (!rewrite_cp_refs_in_element_value( 2262 method_default_annotations, byte_i, THREAD)) { 2263 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2264 ("bad default element_value at %d", i)); 2265 // propagate failure back to caller 2266 return false; 2267 } 2268 } 2269 2270 return true; 2271 } // end rewrite_cp_refs_in_methods_default_annotations() 2272 2273 2274 // Rewrite constant pool references in a class_type_annotations field. 2275 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations( 2276 instanceKlassHandle scratch_class, TRAPS) { 2277 2278 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations(); 2279 if (class_type_annotations == NULL || class_type_annotations->length() == 0) { 2280 // no class_type_annotations so nothing to do 2281 return true; 2282 } 2283 2284 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2285 ("class_type_annotations length=%d", class_type_annotations->length())); 2286 2287 int byte_i = 0; // byte index into class_type_annotations 2288 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations, 2289 byte_i, "ClassFile", THREAD); 2290 } // end rewrite_cp_refs_in_class_type_annotations() 2291 2292 2293 // Rewrite constant pool references in a fields_type_annotations field. 2294 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations( 2295 instanceKlassHandle scratch_class, TRAPS) { 2296 2297 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations(); 2298 if (fields_type_annotations == NULL || fields_type_annotations->length() == 0) { 2299 // no fields_type_annotations so nothing to do 2300 return true; 2301 } 2302 2303 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2304 ("fields_type_annotations length=%d", fields_type_annotations->length())); 2305 2306 for (int i = 0; i < fields_type_annotations->length(); i++) { 2307 AnnotationArray* field_type_annotations = fields_type_annotations->at(i); 2308 if (field_type_annotations == NULL || field_type_annotations->length() == 0) { 2309 // this field does not have any annotations so skip it 2310 continue; 2311 } 2312 2313 int byte_i = 0; // byte index into field_type_annotations 2314 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations, 2315 byte_i, "field_info", THREAD)) { 2316 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2317 ("bad field_type_annotations at %d", i)); 2318 // propagate failure back to caller 2319 return false; 2320 } 2321 } 2322 2323 return true; 2324 } // end rewrite_cp_refs_in_fields_type_annotations() 2325 2326 2327 // Rewrite constant pool references in a methods_type_annotations field. 2328 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations( 2329 instanceKlassHandle scratch_class, TRAPS) { 2330 2331 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2332 Method* m = scratch_class->methods()->at(i); 2333 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations(); 2334 2335 if (method_type_annotations == NULL || method_type_annotations->length() == 0) { 2336 // this method does not have any annotations so skip it 2337 continue; 2338 } 2339 2340 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2341 ("methods type_annotations length=%d", method_type_annotations->length())); 2342 2343 int byte_i = 0; // byte index into method_type_annotations 2344 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations, 2345 byte_i, "method_info", THREAD)) { 2346 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2347 ("bad method_type_annotations at %d", i)); 2348 // propagate failure back to caller 2349 return false; 2350 } 2351 } 2352 2353 return true; 2354 } // end rewrite_cp_refs_in_methods_type_annotations() 2355 2356 2357 // Rewrite constant pool references in a type_annotations 2358 // field. This "structure" is adapted from the 2359 // RuntimeVisibleTypeAnnotations_attribute described in 2360 // section 4.7.20 of the Java SE 8 Edition of the VM spec: 2361 // 2362 // type_annotations_typeArray { 2363 // u2 num_annotations; 2364 // type_annotation annotations[num_annotations]; 2365 // } 2366 // 2367 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray( 2368 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2369 const char * location_mesg, TRAPS) { 2370 2371 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2372 // not enough room for num_annotations field 2373 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2374 ("length() is too small for num_annotations field")); 2375 return false; 2376 } 2377 2378 u2 num_annotations = Bytes::get_Java_u2((address) 2379 type_annotations_typeArray->adr_at(byte_i_ref)); 2380 byte_i_ref += 2; 2381 2382 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2383 ("num_type_annotations=%d", num_annotations)); 2384 2385 int calc_num_annotations = 0; 2386 for (; calc_num_annotations < num_annotations; calc_num_annotations++) { 2387 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray, 2388 byte_i_ref, location_mesg, THREAD)) { 2389 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2390 ("bad type_annotation_struct at %d", calc_num_annotations)); 2391 // propagate failure back to caller 2392 return false; 2393 } 2394 } 2395 assert(num_annotations == calc_num_annotations, "sanity check"); 2396 2397 if (byte_i_ref != type_annotations_typeArray->length()) { 2398 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2399 ("read wrong amount of bytes at end of processing " 2400 "type_annotations_typeArray (%d of %d bytes were read)", 2401 byte_i_ref, type_annotations_typeArray->length())); 2402 return false; 2403 } 2404 2405 return true; 2406 } // end rewrite_cp_refs_in_type_annotations_typeArray() 2407 2408 2409 // Rewrite constant pool references in a type_annotation 2410 // field. This "structure" is adapted from the 2411 // RuntimeVisibleTypeAnnotations_attribute described in 2412 // section 4.7.20 of the Java SE 8 Edition of the VM spec: 2413 // 2414 // type_annotation { 2415 // u1 target_type; 2416 // union { 2417 // type_parameter_target; 2418 // supertype_target; 2419 // type_parameter_bound_target; 2420 // empty_target; 2421 // method_formal_parameter_target; 2422 // throws_target; 2423 // localvar_target; 2424 // catch_target; 2425 // offset_target; 2426 // type_argument_target; 2427 // } target_info; 2428 // type_path target_path; 2429 // annotation anno; 2430 // } 2431 // 2432 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct( 2433 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2434 const char * location_mesg, TRAPS) { 2435 2436 if (!skip_type_annotation_target(type_annotations_typeArray, 2437 byte_i_ref, location_mesg, THREAD)) { 2438 return false; 2439 } 2440 2441 if (!skip_type_annotation_type_path(type_annotations_typeArray, 2442 byte_i_ref, THREAD)) { 2443 return false; 2444 } 2445 2446 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray, 2447 byte_i_ref, THREAD)) { 2448 return false; 2449 } 2450 2451 return true; 2452 } // end rewrite_cp_refs_in_type_annotation_struct() 2453 2454 2455 // Read, verify and skip over the target_type and target_info part 2456 // so that rewriting can continue in the later parts of the struct. 2457 // 2458 // u1 target_type; 2459 // union { 2460 // type_parameter_target; 2461 // supertype_target; 2462 // type_parameter_bound_target; 2463 // empty_target; 2464 // method_formal_parameter_target; 2465 // throws_target; 2466 // localvar_target; 2467 // catch_target; 2468 // offset_target; 2469 // type_argument_target; 2470 // } target_info; 2471 // 2472 bool VM_RedefineClasses::skip_type_annotation_target( 2473 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2474 const char * location_mesg, TRAPS) { 2475 2476 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2477 // not enough room for a target_type let alone the rest of a type_annotation 2478 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2479 ("length() is too small for a target_type")); 2480 return false; 2481 } 2482 2483 u1 target_type = type_annotations_typeArray->at(byte_i_ref); 2484 byte_i_ref += 1; 2485 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("target_type=0x%.2x", target_type)); 2486 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("location=%s", location_mesg)); 2487 2488 // Skip over target_info 2489 switch (target_type) { 2490 case 0x00: 2491 // kind: type parameter declaration of generic class or interface 2492 // location: ClassFile 2493 case 0x01: 2494 // kind: type parameter declaration of generic method or constructor 2495 // location: method_info 2496 2497 { 2498 // struct: 2499 // type_parameter_target { 2500 // u1 type_parameter_index; 2501 // } 2502 // 2503 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2504 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2505 ("length() is too small for a type_parameter_target")); 2506 return false; 2507 } 2508 2509 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2510 byte_i_ref += 1; 2511 2512 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2513 ("type_parameter_target: type_parameter_index=%d", 2514 type_parameter_index)); 2515 } break; 2516 2517 case 0x10: 2518 // kind: type in extends clause of class or interface declaration 2519 // (including the direct superclass of an anonymous class declaration), 2520 // or in implements clause of interface declaration 2521 // location: ClassFile 2522 2523 { 2524 // struct: 2525 // supertype_target { 2526 // u2 supertype_index; 2527 // } 2528 // 2529 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2530 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2531 ("length() is too small for a supertype_target")); 2532 return false; 2533 } 2534 2535 u2 supertype_index = Bytes::get_Java_u2((address) 2536 type_annotations_typeArray->adr_at(byte_i_ref)); 2537 byte_i_ref += 2; 2538 2539 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2540 ("supertype_target: supertype_index=%d", supertype_index)); 2541 } break; 2542 2543 case 0x11: 2544 // kind: type in bound of type parameter declaration of generic class or interface 2545 // location: ClassFile 2546 case 0x12: 2547 // kind: type in bound of type parameter declaration of generic method or constructor 2548 // location: method_info 2549 2550 { 2551 // struct: 2552 // type_parameter_bound_target { 2553 // u1 type_parameter_index; 2554 // u1 bound_index; 2555 // } 2556 // 2557 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2558 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2559 ("length() is too small for a type_parameter_bound_target")); 2560 return false; 2561 } 2562 2563 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2564 byte_i_ref += 1; 2565 u1 bound_index = type_annotations_typeArray->at(byte_i_ref); 2566 byte_i_ref += 1; 2567 2568 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2569 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d", 2570 type_parameter_index, bound_index)); 2571 } break; 2572 2573 case 0x13: 2574 // kind: type in field declaration 2575 // location: field_info 2576 case 0x14: 2577 // kind: return type of method, or type of newly constructed object 2578 // location: method_info 2579 case 0x15: 2580 // kind: receiver type of method or constructor 2581 // location: method_info 2582 2583 { 2584 // struct: 2585 // empty_target { 2586 // } 2587 // 2588 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2589 ("empty_target")); 2590 } break; 2591 2592 case 0x16: 2593 // kind: type in formal parameter declaration of method, constructor, or lambda expression 2594 // location: method_info 2595 2596 { 2597 // struct: 2598 // formal_parameter_target { 2599 // u1 formal_parameter_index; 2600 // } 2601 // 2602 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2603 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2604 ("length() is too small for a formal_parameter_target")); 2605 return false; 2606 } 2607 2608 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2609 byte_i_ref += 1; 2610 2611 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2612 ("formal_parameter_target: formal_parameter_index=%d", 2613 formal_parameter_index)); 2614 } break; 2615 2616 case 0x17: 2617 // kind: type in throws clause of method or constructor 2618 // location: method_info 2619 2620 { 2621 // struct: 2622 // throws_target { 2623 // u2 throws_type_index 2624 // } 2625 // 2626 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2627 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2628 ("length() is too small for a throws_target")); 2629 return false; 2630 } 2631 2632 u2 throws_type_index = Bytes::get_Java_u2((address) 2633 type_annotations_typeArray->adr_at(byte_i_ref)); 2634 byte_i_ref += 2; 2635 2636 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2637 ("throws_target: throws_type_index=%d", throws_type_index)); 2638 } break; 2639 2640 case 0x40: 2641 // kind: type in local variable declaration 2642 // location: Code 2643 case 0x41: 2644 // kind: type in resource variable declaration 2645 // location: Code 2646 2647 { 2648 // struct: 2649 // localvar_target { 2650 // u2 table_length; 2651 // struct { 2652 // u2 start_pc; 2653 // u2 length; 2654 // u2 index; 2655 // } table[table_length]; 2656 // } 2657 // 2658 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2659 // not enough room for a table_length let alone the rest of a localvar_target 2660 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2661 ("length() is too small for a localvar_target table_length")); 2662 return false; 2663 } 2664 2665 u2 table_length = Bytes::get_Java_u2((address) 2666 type_annotations_typeArray->adr_at(byte_i_ref)); 2667 byte_i_ref += 2; 2668 2669 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2670 ("localvar_target: table_length=%d", table_length)); 2671 2672 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry 2673 int table_size = table_length * table_struct_size; 2674 2675 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) { 2676 // not enough room for a table 2677 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2678 ("length() is too small for a table array of length %d", table_length)); 2679 return false; 2680 } 2681 2682 // Skip over table 2683 byte_i_ref += table_size; 2684 } break; 2685 2686 case 0x42: 2687 // kind: type in exception parameter declaration 2688 // location: Code 2689 2690 { 2691 // struct: 2692 // catch_target { 2693 // u2 exception_table_index; 2694 // } 2695 // 2696 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2697 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2698 ("length() is too small for a catch_target")); 2699 return false; 2700 } 2701 2702 u2 exception_table_index = Bytes::get_Java_u2((address) 2703 type_annotations_typeArray->adr_at(byte_i_ref)); 2704 byte_i_ref += 2; 2705 2706 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2707 ("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 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2731 ("length() is too small for a offset_target")); 2732 return false; 2733 } 2734 2735 u2 offset = Bytes::get_Java_u2((address) 2736 type_annotations_typeArray->adr_at(byte_i_ref)); 2737 byte_i_ref += 2; 2738 2739 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2740 ("offset_target: offset=%d", offset)); 2741 } break; 2742 2743 case 0x47: 2744 // kind: type in cast expression 2745 // location: Code 2746 case 0x48: 2747 // kind: type argument for generic constructor in new expression or 2748 // explicit constructor invocation statement 2749 // location: Code 2750 case 0x49: 2751 // kind: type argument for generic method in method invocation expression 2752 // location: Code 2753 case 0x4A: 2754 // kind: type argument for generic constructor in method reference expression using ::new 2755 // location: Code 2756 case 0x4B: 2757 // kind: type argument for generic method in method reference expression using ::Identifier 2758 // location: Code 2759 2760 { 2761 // struct: 2762 // type_argument_target { 2763 // u2 offset; 2764 // u1 type_argument_index; 2765 // } 2766 // 2767 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) { 2768 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2769 ("length() is too small for a type_argument_target")); 2770 return false; 2771 } 2772 2773 u2 offset = Bytes::get_Java_u2((address) 2774 type_annotations_typeArray->adr_at(byte_i_ref)); 2775 byte_i_ref += 2; 2776 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref); 2777 byte_i_ref += 1; 2778 2779 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2780 ("type_argument_target: offset=%d, type_argument_index=%d", 2781 offset, type_argument_index)); 2782 } break; 2783 2784 default: 2785 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2786 ("unknown target_type")); 2787 #ifdef ASSERT 2788 ShouldNotReachHere(); 2789 #endif 2790 return false; 2791 } 2792 2793 return true; 2794 } // end skip_type_annotation_target() 2795 2796 2797 // Read, verify and skip over the type_path part so that rewriting 2798 // can continue in the later parts of the struct. 2799 // 2800 // type_path { 2801 // u1 path_length; 2802 // { 2803 // u1 type_path_kind; 2804 // u1 type_argument_index; 2805 // } path[path_length]; 2806 // } 2807 // 2808 bool VM_RedefineClasses::skip_type_annotation_type_path( 2809 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, TRAPS) { 2810 2811 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2812 // not enough room for a path_length let alone the rest of the type_path 2813 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2814 ("length() is too small for a type_path")); 2815 return false; 2816 } 2817 2818 u1 path_length = type_annotations_typeArray->at(byte_i_ref); 2819 byte_i_ref += 1; 2820 2821 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2822 ("type_path: path_length=%d", path_length)); 2823 2824 int calc_path_length = 0; 2825 for (; calc_path_length < path_length; calc_path_length++) { 2826 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) { 2827 // not enough room for a path 2828 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2829 ("length() is too small for path entry %d of %d", 2830 calc_path_length, path_length)); 2831 return false; 2832 } 2833 2834 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref); 2835 byte_i_ref += 1; 2836 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref); 2837 byte_i_ref += 1; 2838 2839 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2840 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d", 2841 calc_path_length, type_path_kind, type_argument_index)); 2842 2843 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) { 2844 // not enough room for a path 2845 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2846 ("inconsistent type_path values")); 2847 return false; 2848 } 2849 } 2850 assert(path_length == calc_path_length, "sanity check"); 2851 2852 return true; 2853 } // end skip_type_annotation_type_path() 2854 2855 2856 // Rewrite constant pool references in the method's stackmap table. 2857 // These "structures" are adapted from the StackMapTable_attribute that 2858 // is described in section 4.8.4 of the 6.0 version of the VM spec 2859 // (dated 2005.10.26): 2860 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf 2861 // 2862 // stack_map { 2863 // u2 number_of_entries; 2864 // stack_map_frame entries[number_of_entries]; 2865 // } 2866 // 2867 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table( 2868 methodHandle method, TRAPS) { 2869 2870 if (!method->has_stackmap_table()) { 2871 return; 2872 } 2873 2874 AnnotationArray* stackmap_data = method->stackmap_data(); 2875 address stackmap_p = (address)stackmap_data->adr_at(0); 2876 address stackmap_end = stackmap_p + stackmap_data->length(); 2877 2878 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries"); 2879 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p); 2880 stackmap_p += 2; 2881 2882 RC_TRACE_WITH_THREAD(0x04000000, THREAD, 2883 ("number_of_entries=%u", number_of_entries)); 2884 2885 // walk through each stack_map_frame 2886 u2 calc_number_of_entries = 0; 2887 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) { 2888 // The stack_map_frame structure is a u1 frame_type followed by 2889 // 0 or more bytes of data: 2890 // 2891 // union stack_map_frame { 2892 // same_frame; 2893 // same_locals_1_stack_item_frame; 2894 // same_locals_1_stack_item_frame_extended; 2895 // chop_frame; 2896 // same_frame_extended; 2897 // append_frame; 2898 // full_frame; 2899 // } 2900 2901 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type"); 2902 u1 frame_type = *stackmap_p; 2903 stackmap_p++; 2904 2905 // same_frame { 2906 // u1 frame_type = SAME; /* 0-63 */ 2907 // } 2908 if (frame_type <= 63) { 2909 // nothing more to do for same_frame 2910 } 2911 2912 // same_locals_1_stack_item_frame { 2913 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */ 2914 // verification_type_info stack[1]; 2915 // } 2916 else if (frame_type >= 64 && frame_type <= 127) { 2917 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2918 calc_number_of_entries, frame_type, THREAD); 2919 } 2920 2921 // reserved for future use 2922 else if (frame_type >= 128 && frame_type <= 246) { 2923 // nothing more to do for reserved frame_types 2924 } 2925 2926 // same_locals_1_stack_item_frame_extended { 2927 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */ 2928 // u2 offset_delta; 2929 // verification_type_info stack[1]; 2930 // } 2931 else if (frame_type == 247) { 2932 stackmap_p += 2; 2933 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2934 calc_number_of_entries, frame_type, THREAD); 2935 } 2936 2937 // chop_frame { 2938 // u1 frame_type = CHOP; /* 248-250 */ 2939 // u2 offset_delta; 2940 // } 2941 else if (frame_type >= 248 && frame_type <= 250) { 2942 stackmap_p += 2; 2943 } 2944 2945 // same_frame_extended { 2946 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/ 2947 // u2 offset_delta; 2948 // } 2949 else if (frame_type == 251) { 2950 stackmap_p += 2; 2951 } 2952 2953 // append_frame { 2954 // u1 frame_type = APPEND; /* 252-254 */ 2955 // u2 offset_delta; 2956 // verification_type_info locals[frame_type - 251]; 2957 // } 2958 else if (frame_type >= 252 && frame_type <= 254) { 2959 assert(stackmap_p + 2 <= stackmap_end, 2960 "no room for offset_delta"); 2961 stackmap_p += 2; 2962 u1 len = frame_type - 251; 2963 for (u1 i = 0; i < len; i++) { 2964 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2965 calc_number_of_entries, frame_type, THREAD); 2966 } 2967 } 2968 2969 // full_frame { 2970 // u1 frame_type = FULL_FRAME; /* 255 */ 2971 // u2 offset_delta; 2972 // u2 number_of_locals; 2973 // verification_type_info locals[number_of_locals]; 2974 // u2 number_of_stack_items; 2975 // verification_type_info stack[number_of_stack_items]; 2976 // } 2977 else if (frame_type == 255) { 2978 assert(stackmap_p + 2 + 2 <= stackmap_end, 2979 "no room for smallest full_frame"); 2980 stackmap_p += 2; 2981 2982 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p); 2983 stackmap_p += 2; 2984 2985 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) { 2986 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2987 calc_number_of_entries, frame_type, THREAD); 2988 } 2989 2990 // Use the largest size for the number_of_stack_items, but only get 2991 // the right number of bytes. 2992 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p); 2993 stackmap_p += 2; 2994 2995 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) { 2996 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2997 calc_number_of_entries, frame_type, THREAD); 2998 } 2999 } 3000 } // end while there is a stack_map_frame 3001 assert(number_of_entries == calc_number_of_entries, "sanity check"); 3002 } // end rewrite_cp_refs_in_stack_map_table() 3003 3004 3005 // Rewrite constant pool references in the verification type info 3006 // portion of the method's stackmap table. These "structures" are 3007 // adapted from the StackMapTable_attribute that is described in 3008 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26): 3009 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf 3010 // 3011 // The verification_type_info structure is a u1 tag followed by 0 or 3012 // more bytes of data: 3013 // 3014 // union verification_type_info { 3015 // Top_variable_info; 3016 // Integer_variable_info; 3017 // Float_variable_info; 3018 // Long_variable_info; 3019 // Double_variable_info; 3020 // Null_variable_info; 3021 // UninitializedThis_variable_info; 3022 // Object_variable_info; 3023 // Uninitialized_variable_info; 3024 // } 3025 // 3026 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info( 3027 address& stackmap_p_ref, address stackmap_end, u2 frame_i, 3028 u1 frame_type, TRAPS) { 3029 3030 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag"); 3031 u1 tag = *stackmap_p_ref; 3032 stackmap_p_ref++; 3033 3034 switch (tag) { 3035 // Top_variable_info { 3036 // u1 tag = ITEM_Top; /* 0 */ 3037 // } 3038 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top 3039 case 0: // fall through 3040 3041 // Integer_variable_info { 3042 // u1 tag = ITEM_Integer; /* 1 */ 3043 // } 3044 case ITEM_Integer: // fall through 3045 3046 // Float_variable_info { 3047 // u1 tag = ITEM_Float; /* 2 */ 3048 // } 3049 case ITEM_Float: // fall through 3050 3051 // Double_variable_info { 3052 // u1 tag = ITEM_Double; /* 3 */ 3053 // } 3054 case ITEM_Double: // fall through 3055 3056 // Long_variable_info { 3057 // u1 tag = ITEM_Long; /* 4 */ 3058 // } 3059 case ITEM_Long: // fall through 3060 3061 // Null_variable_info { 3062 // u1 tag = ITEM_Null; /* 5 */ 3063 // } 3064 case ITEM_Null: // fall through 3065 3066 // UninitializedThis_variable_info { 3067 // u1 tag = ITEM_UninitializedThis; /* 6 */ 3068 // } 3069 case ITEM_UninitializedThis: 3070 // nothing more to do for the above tag types 3071 break; 3072 3073 // Object_variable_info { 3074 // u1 tag = ITEM_Object; /* 7 */ 3075 // u2 cpool_index; 3076 // } 3077 case ITEM_Object: 3078 { 3079 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index"); 3080 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref); 3081 u2 new_cp_index = find_new_index(cpool_index); 3082 if (new_cp_index != 0) { 3083 RC_TRACE_WITH_THREAD(0x04000000, THREAD, 3084 ("mapped old cpool_index=%d", cpool_index)); 3085 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index); 3086 cpool_index = new_cp_index; 3087 } 3088 stackmap_p_ref += 2; 3089 3090 RC_TRACE_WITH_THREAD(0x04000000, THREAD, 3091 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i, 3092 frame_type, cpool_index)); 3093 } break; 3094 3095 // Uninitialized_variable_info { 3096 // u1 tag = ITEM_Uninitialized; /* 8 */ 3097 // u2 offset; 3098 // } 3099 case ITEM_Uninitialized: 3100 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset"); 3101 stackmap_p_ref += 2; 3102 break; 3103 3104 default: 3105 RC_TRACE_WITH_THREAD(0x04000000, THREAD, 3106 ("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag)); 3107 ShouldNotReachHere(); 3108 break; 3109 } // end switch (tag) 3110 } // end rewrite_cp_refs_in_verification_type_info() 3111 3112 3113 // Change the constant pool associated with klass scratch_class to 3114 // scratch_cp. If shrink is true, then scratch_cp_length elements 3115 // are copied from scratch_cp to a smaller constant pool and the 3116 // smaller constant pool is associated with scratch_class. 3117 void VM_RedefineClasses::set_new_constant_pool( 3118 ClassLoaderData* loader_data, 3119 instanceKlassHandle scratch_class, constantPoolHandle scratch_cp, 3120 int scratch_cp_length, TRAPS) { 3121 assert(scratch_cp->length() >= scratch_cp_length, "sanity check"); 3122 3123 // scratch_cp is a merged constant pool and has enough space for a 3124 // worst case merge situation. We want to associate the minimum 3125 // sized constant pool with the klass to save space. 3126 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK); 3127 constantPoolHandle smaller_cp(THREAD, cp); 3128 3129 // preserve version() value in the smaller copy 3130 int version = scratch_cp->version(); 3131 assert(version != 0, "sanity check"); 3132 smaller_cp->set_version(version); 3133 3134 // attach klass to new constant pool 3135 // reference to the cp holder is needed for copy_operands() 3136 smaller_cp->set_pool_holder(scratch_class()); 3137 3138 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD); 3139 if (HAS_PENDING_EXCEPTION) { 3140 // Exception is handled in the caller 3141 loader_data->add_to_deallocate_list(smaller_cp()); 3142 return; 3143 } 3144 scratch_cp = smaller_cp; 3145 3146 // attach new constant pool to klass 3147 scratch_class->set_constants(scratch_cp()); 3148 3149 int i; // for portability 3150 3151 // update each field in klass to use new constant pool indices as needed 3152 for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) { 3153 jshort cur_index = fs.name_index(); 3154 jshort new_index = find_new_index(cur_index); 3155 if (new_index != 0) { 3156 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3157 ("field-name_index change: %d to %d", cur_index, new_index)); 3158 fs.set_name_index(new_index); 3159 } 3160 cur_index = fs.signature_index(); 3161 new_index = find_new_index(cur_index); 3162 if (new_index != 0) { 3163 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3164 ("field-signature_index change: %d to %d", cur_index, new_index)); 3165 fs.set_signature_index(new_index); 3166 } 3167 cur_index = fs.initval_index(); 3168 new_index = find_new_index(cur_index); 3169 if (new_index != 0) { 3170 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3171 ("field-initval_index change: %d to %d", cur_index, new_index)); 3172 fs.set_initval_index(new_index); 3173 } 3174 cur_index = fs.generic_signature_index(); 3175 new_index = find_new_index(cur_index); 3176 if (new_index != 0) { 3177 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3178 ("field-generic_signature change: %d to %d", cur_index, new_index)); 3179 fs.set_generic_signature_index(new_index); 3180 } 3181 } // end for each field 3182 3183 // Update constant pool indices in the inner classes info to use 3184 // new constant indices as needed. The inner classes info is a 3185 // quadruple: 3186 // (inner_class_info, outer_class_info, inner_name, inner_access_flags) 3187 InnerClassesIterator iter(scratch_class); 3188 for (; !iter.done(); iter.next()) { 3189 int cur_index = iter.inner_class_info_index(); 3190 if (cur_index == 0) { 3191 continue; // JVM spec. allows null inner class refs so skip it 3192 } 3193 int new_index = find_new_index(cur_index); 3194 if (new_index != 0) { 3195 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3196 ("inner_class_info change: %d to %d", cur_index, new_index)); 3197 iter.set_inner_class_info_index(new_index); 3198 } 3199 cur_index = iter.outer_class_info_index(); 3200 new_index = find_new_index(cur_index); 3201 if (new_index != 0) { 3202 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3203 ("outer_class_info change: %d to %d", cur_index, new_index)); 3204 iter.set_outer_class_info_index(new_index); 3205 } 3206 cur_index = iter.inner_name_index(); 3207 new_index = find_new_index(cur_index); 3208 if (new_index != 0) { 3209 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3210 ("inner_name change: %d to %d", cur_index, new_index)); 3211 iter.set_inner_name_index(new_index); 3212 } 3213 } // end for each inner class 3214 3215 // Attach each method in klass to the new constant pool and update 3216 // to use new constant pool indices as needed: 3217 Array<Method*>* methods = scratch_class->methods(); 3218 for (i = methods->length() - 1; i >= 0; i--) { 3219 methodHandle method(THREAD, methods->at(i)); 3220 method->set_constants(scratch_cp()); 3221 3222 int new_index = find_new_index(method->name_index()); 3223 if (new_index != 0) { 3224 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3225 ("method-name_index change: %d to %d", method->name_index(), 3226 new_index)); 3227 method->set_name_index(new_index); 3228 } 3229 new_index = find_new_index(method->signature_index()); 3230 if (new_index != 0) { 3231 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3232 ("method-signature_index change: %d to %d", 3233 method->signature_index(), new_index)); 3234 method->set_signature_index(new_index); 3235 } 3236 new_index = find_new_index(method->generic_signature_index()); 3237 if (new_index != 0) { 3238 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3239 ("method-generic_signature_index change: %d to %d", 3240 method->generic_signature_index(), new_index)); 3241 method->set_generic_signature_index(new_index); 3242 } 3243 3244 // Update constant pool indices in the method's checked exception 3245 // table to use new constant indices as needed. 3246 int cext_length = method->checked_exceptions_length(); 3247 if (cext_length > 0) { 3248 CheckedExceptionElement * cext_table = 3249 method->checked_exceptions_start(); 3250 for (int j = 0; j < cext_length; j++) { 3251 int cur_index = cext_table[j].class_cp_index; 3252 int new_index = find_new_index(cur_index); 3253 if (new_index != 0) { 3254 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3255 ("cext-class_cp_index change: %d to %d", cur_index, new_index)); 3256 cext_table[j].class_cp_index = (u2)new_index; 3257 } 3258 } // end for each checked exception table entry 3259 } // end if there are checked exception table entries 3260 3261 // Update each catch type index in the method's exception table 3262 // to use new constant pool indices as needed. The exception table 3263 // holds quadruple entries of the form: 3264 // (beg_bci, end_bci, handler_bci, klass_index) 3265 3266 ExceptionTable ex_table(method()); 3267 int ext_length = ex_table.length(); 3268 3269 for (int j = 0; j < ext_length; j ++) { 3270 int cur_index = ex_table.catch_type_index(j); 3271 int new_index = find_new_index(cur_index); 3272 if (new_index != 0) { 3273 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3274 ("ext-klass_index change: %d to %d", cur_index, new_index)); 3275 ex_table.set_catch_type_index(j, new_index); 3276 } 3277 } // end for each exception table entry 3278 3279 // Update constant pool indices in the method's local variable 3280 // table to use new constant indices as needed. The local variable 3281 // table hold sextuple entries of the form: 3282 // (start_pc, length, name_index, descriptor_index, signature_index, slot) 3283 int lvt_length = method->localvariable_table_length(); 3284 if (lvt_length > 0) { 3285 LocalVariableTableElement * lv_table = 3286 method->localvariable_table_start(); 3287 for (int j = 0; j < lvt_length; j++) { 3288 int cur_index = lv_table[j].name_cp_index; 3289 int new_index = find_new_index(cur_index); 3290 if (new_index != 0) { 3291 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3292 ("lvt-name_cp_index change: %d to %d", cur_index, new_index)); 3293 lv_table[j].name_cp_index = (u2)new_index; 3294 } 3295 cur_index = lv_table[j].descriptor_cp_index; 3296 new_index = find_new_index(cur_index); 3297 if (new_index != 0) { 3298 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3299 ("lvt-descriptor_cp_index change: %d to %d", cur_index, 3300 new_index)); 3301 lv_table[j].descriptor_cp_index = (u2)new_index; 3302 } 3303 cur_index = lv_table[j].signature_cp_index; 3304 new_index = find_new_index(cur_index); 3305 if (new_index != 0) { 3306 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3307 ("lvt-signature_cp_index change: %d to %d", cur_index, new_index)); 3308 lv_table[j].signature_cp_index = (u2)new_index; 3309 } 3310 } // end for each local variable table entry 3311 } // end if there are local variable table entries 3312 3313 rewrite_cp_refs_in_stack_map_table(method, THREAD); 3314 } // end for each method 3315 } // end set_new_constant_pool() 3316 3317 3318 // Unevolving classes may point to methods of the_class directly 3319 // from their constant pool caches, itables, and/or vtables. We 3320 // use the ClassLoaderDataGraph::classes_do() facility and this helper 3321 // to fix up these pointers. 3322 3323 // Adjust cpools and vtables closure 3324 void VM_RedefineClasses::AdjustCpoolCacheAndVtable::do_klass(Klass* k) { 3325 3326 // This is a very busy routine. We don't want too much tracing 3327 // printed out. 3328 bool trace_name_printed = false; 3329 InstanceKlass *the_class = InstanceKlass::cast(_the_class_oop); 3330 3331 // Very noisy: only enable this call if you are trying to determine 3332 // that a specific class gets found by this routine. 3333 // RC_TRACE macro has an embedded ResourceMark 3334 // RC_TRACE_WITH_THREAD(0x00100000, THREAD, 3335 // ("adjust check: name=%s", k->external_name())); 3336 // trace_name_printed = true; 3337 3338 // If the class being redefined is java.lang.Object, we need to fix all 3339 // array class vtables also 3340 if (k->oop_is_array() && _the_class_oop == SystemDictionary::Object_klass()) { 3341 k->vtable()->adjust_method_entries(the_class, &trace_name_printed); 3342 3343 } else if (k->oop_is_instance()) { 3344 HandleMark hm(_thread); 3345 InstanceKlass *ik = InstanceKlass::cast(k); 3346 3347 // HotSpot specific optimization! HotSpot does not currently 3348 // support delegation from the bootstrap class loader to a 3349 // user-defined class loader. This means that if the bootstrap 3350 // class loader is the initiating class loader, then it will also 3351 // be the defining class loader. This also means that classes 3352 // loaded by the bootstrap class loader cannot refer to classes 3353 // loaded by a user-defined class loader. Note: a user-defined 3354 // class loader can delegate to the bootstrap class loader. 3355 // 3356 // If the current class being redefined has a user-defined class 3357 // loader as its defining class loader, then we can skip all 3358 // classes loaded by the bootstrap class loader. 3359 bool is_user_defined = 3360 InstanceKlass::cast(_the_class_oop)->class_loader() != NULL; 3361 if (is_user_defined && ik->class_loader() == NULL) { 3362 return; 3363 } 3364 3365 // Fix the vtable embedded in the_class and subclasses of the_class, 3366 // if one exists. We discard scratch_class and we don't keep an 3367 // InstanceKlass around to hold obsolete methods so we don't have 3368 // any other InstanceKlass embedded vtables to update. The vtable 3369 // holds the Method*s for virtual (but not final) methods. 3370 // Default methods, or concrete methods in interfaces are stored 3371 // in the vtable, so if an interface changes we need to check 3372 // adjust_method_entries() for every InstanceKlass, which will also 3373 // adjust the default method vtable indices. 3374 // We also need to adjust any default method entries that are 3375 // not yet in the vtable, because the vtable setup is in progress. 3376 // This must be done after we adjust the default_methods and 3377 // default_vtable_indices for methods already in the vtable. 3378 // If redefining Unsafe, walk all the vtables looking for entries. 3379 if (ik->vtable_length() > 0 && (_the_class_oop->is_interface() 3380 || _the_class_oop == SystemDictionary::misc_Unsafe_klass() 3381 || ik->is_subtype_of(_the_class_oop))) { 3382 // ik->vtable() creates a wrapper object; rm cleans it up 3383 ResourceMark rm(_thread); 3384 3385 ik->vtable()->adjust_method_entries(the_class, &trace_name_printed); 3386 ik->adjust_default_methods(the_class, &trace_name_printed); 3387 } 3388 3389 // If the current class has an itable and we are either redefining an 3390 // interface or if the current class is a subclass of the_class, then 3391 // we potentially have to fix the itable. If we are redefining an 3392 // interface, then we have to call adjust_method_entries() for 3393 // every InstanceKlass that has an itable since there isn't a 3394 // subclass relationship between an interface and an InstanceKlass. 3395 // If redefining Unsafe, walk all the itables looking for entries. 3396 if (ik->itable_length() > 0 && (_the_class_oop->is_interface() 3397 || _the_class_oop == SystemDictionary::misc_Unsafe_klass() 3398 || ik->is_subclass_of(_the_class_oop))) { 3399 // ik->itable() creates a wrapper object; rm cleans it up 3400 ResourceMark rm(_thread); 3401 3402 ik->itable()->adjust_method_entries(the_class, &trace_name_printed); 3403 } 3404 3405 // The constant pools in other classes (other_cp) can refer to 3406 // methods in the_class. We have to update method information in 3407 // other_cp's cache. If other_cp has a previous version, then we 3408 // have to repeat the process for each previous version. The 3409 // constant pool cache holds the Method*s for non-virtual 3410 // methods and for virtual, final methods. 3411 // 3412 // Special case: if the current class is the_class, then new_cp 3413 // has already been attached to the_class and old_cp has already 3414 // been added as a previous version. The new_cp doesn't have any 3415 // cached references to old methods so it doesn't need to be 3416 // updated. We can simply start with the previous version(s) in 3417 // that case. 3418 constantPoolHandle other_cp; 3419 ConstantPoolCache* cp_cache; 3420 3421 if (ik != _the_class_oop) { 3422 // this klass' constant pool cache may need adjustment 3423 other_cp = constantPoolHandle(ik->constants()); 3424 cp_cache = other_cp->cache(); 3425 if (cp_cache != NULL) { 3426 cp_cache->adjust_method_entries(the_class, &trace_name_printed); 3427 } 3428 } 3429 3430 // the previous versions' constant pool caches may need adjustment 3431 for (InstanceKlass* pv_node = ik->previous_versions(); 3432 pv_node != NULL; 3433 pv_node = pv_node->previous_versions()) { 3434 cp_cache = pv_node->constants()->cache(); 3435 if (cp_cache != NULL) { 3436 cp_cache->adjust_method_entries(pv_node, &trace_name_printed); 3437 } 3438 } 3439 } 3440 } 3441 3442 // Clean method data for this class 3443 void VM_RedefineClasses::MethodDataCleaner::do_klass(Klass* k) { 3444 if (k->oop_is_instance()) { 3445 InstanceKlass *ik = InstanceKlass::cast(k); 3446 // Clean MethodData of this class's methods so they don't refer to 3447 // old methods that are no longer running. 3448 Array<Method*>* methods = ik->methods(); 3449 int num_methods = methods->length(); 3450 for (int index = 0; index < num_methods; ++index) { 3451 if (methods->at(index)->method_data() != NULL) { 3452 methods->at(index)->method_data()->clean_weak_method_links(); 3453 } 3454 } 3455 } 3456 } 3457 3458 void VM_RedefineClasses::update_jmethod_ids() { 3459 for (int j = 0; j < _matching_methods_length; ++j) { 3460 Method* old_method = _matching_old_methods[j]; 3461 jmethodID jmid = old_method->find_jmethod_id_or_null(); 3462 if (jmid != NULL) { 3463 // There is a jmethodID, change it to point to the new method 3464 methodHandle new_method_h(_matching_new_methods[j]); 3465 Method::change_method_associated_with_jmethod_id(jmid, new_method_h()); 3466 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j], 3467 "should be replaced"); 3468 } 3469 } 3470 } 3471 3472 int VM_RedefineClasses::check_methods_and_mark_as_obsolete() { 3473 int emcp_method_count = 0; 3474 int obsolete_count = 0; 3475 int old_index = 0; 3476 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) { 3477 Method* old_method = _matching_old_methods[j]; 3478 Method* new_method = _matching_new_methods[j]; 3479 Method* old_array_method; 3480 3481 // Maintain an old_index into the _old_methods array by skipping 3482 // deleted methods 3483 while ((old_array_method = _old_methods->at(old_index)) != old_method) { 3484 ++old_index; 3485 } 3486 3487 if (MethodComparator::methods_EMCP(old_method, new_method)) { 3488 // The EMCP definition from JSR-163 requires the bytecodes to be 3489 // the same with the exception of constant pool indices which may 3490 // differ. However, the constants referred to by those indices 3491 // must be the same. 3492 // 3493 // We use methods_EMCP() for comparison since constant pool 3494 // merging can remove duplicate constant pool entries that were 3495 // present in the old method and removed from the rewritten new 3496 // method. A faster binary comparison function would consider the 3497 // old and new methods to be different when they are actually 3498 // EMCP. 3499 // 3500 // The old and new methods are EMCP and you would think that we 3501 // could get rid of one of them here and now and save some space. 3502 // However, the concept of EMCP only considers the bytecodes and 3503 // the constant pool entries in the comparison. Other things, 3504 // e.g., the line number table (LNT) or the local variable table 3505 // (LVT) don't count in the comparison. So the new (and EMCP) 3506 // method can have a new LNT that we need so we can't just 3507 // overwrite the new method with the old method. 3508 // 3509 // When this routine is called, we have already attached the new 3510 // methods to the_class so the old methods are effectively 3511 // overwritten. However, if an old method is still executing, 3512 // then the old method cannot be collected until sometime after 3513 // the old method call has returned. So the overwriting of old 3514 // methods by new methods will save us space except for those 3515 // (hopefully few) old methods that are still executing. 3516 // 3517 // A method refers to a ConstMethod* and this presents another 3518 // possible avenue to space savings. The ConstMethod* in the 3519 // new method contains possibly new attributes (LNT, LVT, etc). 3520 // At first glance, it seems possible to save space by replacing 3521 // the ConstMethod* in the old method with the ConstMethod* 3522 // from the new method. The old and new methods would share the 3523 // same ConstMethod* and we would save the space occupied by 3524 // the old ConstMethod*. However, the ConstMethod* contains 3525 // a back reference to the containing method. Sharing the 3526 // ConstMethod* between two methods could lead to confusion in 3527 // the code that uses the back reference. This would lead to 3528 // brittle code that could be broken in non-obvious ways now or 3529 // in the future. 3530 // 3531 // Another possibility is to copy the ConstMethod* from the new 3532 // method to the old method and then overwrite the new method with 3533 // the old method. Since the ConstMethod* contains the bytecodes 3534 // for the method embedded in the oop, this option would change 3535 // the bytecodes out from under any threads executing the old 3536 // method and make the thread's bcp invalid. Since EMCP requires 3537 // that the bytecodes be the same modulo constant pool indices, it 3538 // is straight forward to compute the correct new bcp in the new 3539 // ConstMethod* from the old bcp in the old ConstMethod*. The 3540 // time consuming part would be searching all the frames in all 3541 // of the threads to find all of the calls to the old method. 3542 // 3543 // It looks like we will have to live with the limited savings 3544 // that we get from effectively overwriting the old methods 3545 // when the new methods are attached to the_class. 3546 3547 // Count number of methods that are EMCP. The method will be marked 3548 // old but not obsolete if it is EMCP. 3549 emcp_method_count++; 3550 3551 // An EMCP method is _not_ obsolete. An obsolete method has a 3552 // different jmethodID than the current method. An EMCP method 3553 // has the same jmethodID as the current method. Having the 3554 // same jmethodID for all EMCP versions of a method allows for 3555 // a consistent view of the EMCP methods regardless of which 3556 // EMCP method you happen to have in hand. For example, a 3557 // breakpoint set in one EMCP method will work for all EMCP 3558 // versions of the method including the current one. 3559 } else { 3560 // mark obsolete methods as such 3561 old_method->set_is_obsolete(); 3562 obsolete_count++; 3563 3564 // obsolete methods need a unique idnum so they become new entries in 3565 // the jmethodID cache in InstanceKlass 3566 assert(old_method->method_idnum() == new_method->method_idnum(), "must match"); 3567 u2 num = InstanceKlass::cast(_the_class_oop)->next_method_idnum(); 3568 if (num != ConstMethod::UNSET_IDNUM) { 3569 old_method->set_method_idnum(num); 3570 } 3571 3572 // With tracing we try not to "yack" too much. The position of 3573 // this trace assumes there are fewer obsolete methods than 3574 // EMCP methods. 3575 RC_TRACE(0x00000100, ("mark %s(%s) as obsolete", 3576 old_method->name()->as_C_string(), 3577 old_method->signature()->as_C_string())); 3578 } 3579 old_method->set_is_old(); 3580 } 3581 for (int i = 0; i < _deleted_methods_length; ++i) { 3582 Method* old_method = _deleted_methods[i]; 3583 3584 assert(!old_method->has_vtable_index(), 3585 "cannot delete methods with vtable entries");; 3586 3587 // Mark all deleted methods as old, obsolete and deleted 3588 old_method->set_is_deleted(); 3589 old_method->set_is_old(); 3590 old_method->set_is_obsolete(); 3591 ++obsolete_count; 3592 // With tracing we try not to "yack" too much. The position of 3593 // this trace assumes there are fewer obsolete methods than 3594 // EMCP methods. 3595 RC_TRACE(0x00000100, ("mark deleted %s(%s) as obsolete", 3596 old_method->name()->as_C_string(), 3597 old_method->signature()->as_C_string())); 3598 } 3599 assert((emcp_method_count + obsolete_count) == _old_methods->length(), 3600 "sanity check"); 3601 RC_TRACE(0x00000100, ("EMCP_cnt=%d, obsolete_cnt=%d", emcp_method_count, 3602 obsolete_count)); 3603 return emcp_method_count; 3604 } 3605 3606 // This internal class transfers the native function registration from old methods 3607 // to new methods. It is designed to handle both the simple case of unchanged 3608 // native methods and the complex cases of native method prefixes being added and/or 3609 // removed. 3610 // It expects only to be used during the VM_RedefineClasses op (a safepoint). 3611 // 3612 // This class is used after the new methods have been installed in "the_class". 3613 // 3614 // So, for example, the following must be handled. Where 'm' is a method and 3615 // a number followed by an underscore is a prefix. 3616 // 3617 // Old Name New Name 3618 // Simple transfer to new method m -> m 3619 // Add prefix m -> 1_m 3620 // Remove prefix 1_m -> m 3621 // Simultaneous add of prefixes m -> 3_2_1_m 3622 // Simultaneous removal of prefixes 3_2_1_m -> m 3623 // Simultaneous add and remove 1_m -> 2_m 3624 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m 3625 // 3626 class TransferNativeFunctionRegistration { 3627 private: 3628 instanceKlassHandle the_class; 3629 int prefix_count; 3630 char** prefixes; 3631 3632 // Recursively search the binary tree of possibly prefixed method names. 3633 // Iteration could be used if all agents were well behaved. Full tree walk is 3634 // more resilent to agents not cleaning up intermediate methods. 3635 // Branch at each depth in the binary tree is: 3636 // (1) without the prefix. 3637 // (2) with the prefix. 3638 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...) 3639 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len, 3640 Symbol* signature) { 3641 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len); 3642 if (name_symbol != NULL) { 3643 Method* method = the_class()->lookup_method(name_symbol, signature); 3644 if (method != NULL) { 3645 // Even if prefixed, intermediate methods must exist. 3646 if (method->is_native()) { 3647 // Wahoo, we found a (possibly prefixed) version of the method, return it. 3648 return method; 3649 } 3650 if (depth < prefix_count) { 3651 // Try applying further prefixes (other than this one). 3652 method = search_prefix_name_space(depth+1, name_str, name_len, signature); 3653 if (method != NULL) { 3654 return method; // found 3655 } 3656 3657 // Try adding this prefix to the method name and see if it matches 3658 // another method name. 3659 char* prefix = prefixes[depth]; 3660 size_t prefix_len = strlen(prefix); 3661 size_t trial_len = name_len + prefix_len; 3662 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1); 3663 strcpy(trial_name_str, prefix); 3664 strcat(trial_name_str, name_str); 3665 method = search_prefix_name_space(depth+1, trial_name_str, trial_len, 3666 signature); 3667 if (method != NULL) { 3668 // If found along this branch, it was prefixed, mark as such 3669 method->set_is_prefixed_native(); 3670 return method; // found 3671 } 3672 } 3673 } 3674 } 3675 return NULL; // This whole branch bore nothing 3676 } 3677 3678 // Return the method name with old prefixes stripped away. 3679 char* method_name_without_prefixes(Method* method) { 3680 Symbol* name = method->name(); 3681 char* name_str = name->as_utf8(); 3682 3683 // Old prefixing may be defunct, strip prefixes, if any. 3684 for (int i = prefix_count-1; i >= 0; i--) { 3685 char* prefix = prefixes[i]; 3686 size_t prefix_len = strlen(prefix); 3687 if (strncmp(prefix, name_str, prefix_len) == 0) { 3688 name_str += prefix_len; 3689 } 3690 } 3691 return name_str; 3692 } 3693 3694 // Strip any prefixes off the old native method, then try to find a 3695 // (possibly prefixed) new native that matches it. 3696 Method* strip_and_search_for_new_native(Method* method) { 3697 ResourceMark rm; 3698 char* name_str = method_name_without_prefixes(method); 3699 return search_prefix_name_space(0, name_str, strlen(name_str), 3700 method->signature()); 3701 } 3702 3703 public: 3704 3705 // Construct a native method transfer processor for this class. 3706 TransferNativeFunctionRegistration(instanceKlassHandle _the_class) { 3707 assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); 3708 3709 the_class = _the_class; 3710 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count); 3711 } 3712 3713 // Attempt to transfer any of the old or deleted methods that are native 3714 void transfer_registrations(Method** old_methods, int methods_length) { 3715 for (int j = 0; j < methods_length; j++) { 3716 Method* old_method = old_methods[j]; 3717 3718 if (old_method->is_native() && old_method->has_native_function()) { 3719 Method* new_method = strip_and_search_for_new_native(old_method); 3720 if (new_method != NULL) { 3721 // Actually set the native function in the new method. 3722 // Redefine does not send events (except CFLH), certainly not this 3723 // behind the scenes re-registration. 3724 new_method->set_native_function(old_method->native_function(), 3725 !Method::native_bind_event_is_interesting); 3726 } 3727 } 3728 } 3729 } 3730 }; 3731 3732 // Don't lose the association between a native method and its JNI function. 3733 void VM_RedefineClasses::transfer_old_native_function_registrations(instanceKlassHandle the_class) { 3734 TransferNativeFunctionRegistration transfer(the_class); 3735 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length); 3736 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length); 3737 } 3738 3739 // Deoptimize all compiled code that depends on this class. 3740 // 3741 // If the can_redefine_classes capability is obtained in the onload 3742 // phase then the compiler has recorded all dependencies from startup. 3743 // In that case we need only deoptimize and throw away all compiled code 3744 // that depends on the class. 3745 // 3746 // If can_redefine_classes is obtained sometime after the onload 3747 // phase then the dependency information may be incomplete. In that case 3748 // the first call to RedefineClasses causes all compiled code to be 3749 // thrown away. As can_redefine_classes has been obtained then 3750 // all future compilations will record dependencies so second and 3751 // subsequent calls to RedefineClasses need only throw away code 3752 // that depends on the class. 3753 // 3754 void VM_RedefineClasses::flush_dependent_code(instanceKlassHandle k_h, TRAPS) { 3755 assert_locked_or_safepoint(Compile_lock); 3756 3757 // All dependencies have been recorded from startup or this is a second or 3758 // subsequent use of RedefineClasses 3759 if (JvmtiExport::all_dependencies_are_recorded()) { 3760 CodeCache::flush_evol_dependents_on(k_h); 3761 } else { 3762 CodeCache::mark_all_nmethods_for_deoptimization(); 3763 3764 ResourceMark rm(THREAD); 3765 DeoptimizationMarker dm; 3766 3767 // Deoptimize all activations depending on marked nmethods 3768 Deoptimization::deoptimize_dependents(); 3769 3770 // Make the dependent methods not entrant (in VM_Deoptimize they are made zombies) 3771 CodeCache::make_marked_nmethods_not_entrant(); 3772 3773 // From now on we know that the dependency information is complete 3774 JvmtiExport::set_all_dependencies_are_recorded(true); 3775 } 3776 } 3777 3778 void VM_RedefineClasses::compute_added_deleted_matching_methods() { 3779 Method* old_method; 3780 Method* new_method; 3781 3782 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 3783 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 3784 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length()); 3785 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 3786 3787 _matching_methods_length = 0; 3788 _deleted_methods_length = 0; 3789 _added_methods_length = 0; 3790 3791 int nj = 0; 3792 int oj = 0; 3793 while (true) { 3794 if (oj >= _old_methods->length()) { 3795 if (nj >= _new_methods->length()) { 3796 break; // we've looked at everything, done 3797 } 3798 // New method at the end 3799 new_method = _new_methods->at(nj); 3800 _added_methods[_added_methods_length++] = new_method; 3801 ++nj; 3802 } else if (nj >= _new_methods->length()) { 3803 // Old method, at the end, is deleted 3804 old_method = _old_methods->at(oj); 3805 _deleted_methods[_deleted_methods_length++] = old_method; 3806 ++oj; 3807 } else { 3808 old_method = _old_methods->at(oj); 3809 new_method = _new_methods->at(nj); 3810 if (old_method->name() == new_method->name()) { 3811 if (old_method->signature() == new_method->signature()) { 3812 _matching_old_methods[_matching_methods_length ] = old_method; 3813 _matching_new_methods[_matching_methods_length++] = new_method; 3814 ++nj; 3815 ++oj; 3816 } else { 3817 // added overloaded have already been moved to the end, 3818 // so this is a deleted overloaded method 3819 _deleted_methods[_deleted_methods_length++] = old_method; 3820 ++oj; 3821 } 3822 } else { // names don't match 3823 if (old_method->name()->fast_compare(new_method->name()) > 0) { 3824 // new method 3825 _added_methods[_added_methods_length++] = new_method; 3826 ++nj; 3827 } else { 3828 // deleted method 3829 _deleted_methods[_deleted_methods_length++] = old_method; 3830 ++oj; 3831 } 3832 } 3833 } 3834 } 3835 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity"); 3836 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity"); 3837 } 3838 3839 3840 void VM_RedefineClasses::swap_annotations(instanceKlassHandle the_class, 3841 instanceKlassHandle scratch_class) { 3842 // Swap annotation fields values 3843 Annotations* old_annotations = the_class->annotations(); 3844 the_class->set_annotations(scratch_class->annotations()); 3845 scratch_class->set_annotations(old_annotations); 3846 } 3847 3848 3849 // Install the redefinition of a class: 3850 // - house keeping (flushing breakpoints and caches, deoptimizing 3851 // dependent compiled code) 3852 // - replacing parts in the_class with parts from scratch_class 3853 // - adding a weak reference to track the obsolete but interesting 3854 // parts of the_class 3855 // - adjusting constant pool caches and vtables in other classes 3856 // that refer to methods in the_class. These adjustments use the 3857 // ClassLoaderDataGraph::classes_do() facility which only allows 3858 // a helper method to be specified. The interesting parameters 3859 // that we would like to pass to the helper method are saved in 3860 // static global fields in the VM operation. 3861 void VM_RedefineClasses::redefine_single_class(jclass the_jclass, 3862 Klass* scratch_class_oop, TRAPS) { 3863 3864 HandleMark hm(THREAD); // make sure handles from this call are freed 3865 RC_TIMER_START(_timer_rsc_phase1); 3866 3867 instanceKlassHandle scratch_class(scratch_class_oop); 3868 3869 oop the_class_mirror = JNIHandles::resolve_non_null(the_jclass); 3870 Klass* the_class_oop = java_lang_Class::as_Klass(the_class_mirror); 3871 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop); 3872 3873 // Remove all breakpoints in methods of this class 3874 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints(); 3875 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class_oop); 3876 3877 // Deoptimize all compiled code that depends on this class 3878 flush_dependent_code(the_class, THREAD); 3879 3880 _old_methods = the_class->methods(); 3881 _new_methods = scratch_class->methods(); 3882 _the_class_oop = the_class_oop; 3883 compute_added_deleted_matching_methods(); 3884 update_jmethod_ids(); 3885 3886 // Attach new constant pool to the original klass. The original 3887 // klass still refers to the old constant pool (for now). 3888 scratch_class->constants()->set_pool_holder(the_class()); 3889 3890 #if 0 3891 // In theory, with constant pool merging in place we should be able 3892 // to save space by using the new, merged constant pool in place of 3893 // the old constant pool(s). By "pool(s)" I mean the constant pool in 3894 // the klass version we are replacing now and any constant pool(s) in 3895 // previous versions of klass. Nice theory, doesn't work in practice. 3896 // When this code is enabled, even simple programs throw NullPointer 3897 // exceptions. I'm guessing that this is caused by some constant pool 3898 // cache difference between the new, merged constant pool and the 3899 // constant pool that was just being used by the klass. I'm keeping 3900 // this code around to archive the idea, but the code has to remain 3901 // disabled for now. 3902 3903 // Attach each old method to the new constant pool. This can be 3904 // done here since we are past the bytecode verification and 3905 // constant pool optimization phases. 3906 for (int i = _old_methods->length() - 1; i >= 0; i--) { 3907 Method* method = _old_methods->at(i); 3908 method->set_constants(scratch_class->constants()); 3909 } 3910 3911 { 3912 // walk all previous versions of the klass 3913 InstanceKlass *ik = (InstanceKlass *)the_class(); 3914 PreviousVersionWalker pvw(ik); 3915 instanceKlassHandle ikh; 3916 do { 3917 ikh = pvw.next_previous_version(); 3918 if (!ikh.is_null()) { 3919 ik = ikh(); 3920 3921 // attach previous version of klass to the new constant pool 3922 ik->set_constants(scratch_class->constants()); 3923 3924 // Attach each method in the previous version of klass to the 3925 // new constant pool 3926 Array<Method*>* prev_methods = ik->methods(); 3927 for (int i = prev_methods->length() - 1; i >= 0; i--) { 3928 Method* method = prev_methods->at(i); 3929 method->set_constants(scratch_class->constants()); 3930 } 3931 } 3932 } while (!ikh.is_null()); 3933 } 3934 #endif 3935 3936 // Replace methods and constantpool 3937 the_class->set_methods(_new_methods); 3938 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods, 3939 // and to be able to undo operation easily. 3940 3941 ConstantPool* old_constants = the_class->constants(); 3942 the_class->set_constants(scratch_class->constants()); 3943 scratch_class->set_constants(old_constants); // See the previous comment. 3944 #if 0 3945 // We are swapping the guts of "the new class" with the guts of "the 3946 // class". Since the old constant pool has just been attached to "the 3947 // new class", it seems logical to set the pool holder in the old 3948 // constant pool also. However, doing this will change the observable 3949 // class hierarchy for any old methods that are still executing. A 3950 // method can query the identity of its "holder" and this query uses 3951 // the method's constant pool link to find the holder. The change in 3952 // holding class from "the class" to "the new class" can confuse 3953 // things. 3954 // 3955 // Setting the old constant pool's holder will also cause 3956 // verification done during vtable initialization below to fail. 3957 // During vtable initialization, the vtable's class is verified to be 3958 // a subtype of the method's holder. The vtable's class is "the 3959 // class" and the method's holder is gotten from the constant pool 3960 // link in the method itself. For "the class"'s directly implemented 3961 // methods, the method holder is "the class" itself (as gotten from 3962 // the new constant pool). The check works fine in this case. The 3963 // check also works fine for methods inherited from super classes. 3964 // 3965 // Miranda methods are a little more complicated. A miranda method is 3966 // provided by an interface when the class implementing the interface 3967 // does not provide its own method. These interfaces are implemented 3968 // internally as an InstanceKlass. These special instanceKlasses 3969 // share the constant pool of the class that "implements" the 3970 // interface. By sharing the constant pool, the method holder of a 3971 // miranda method is the class that "implements" the interface. In a 3972 // non-redefine situation, the subtype check works fine. However, if 3973 // the old constant pool's pool holder is modified, then the check 3974 // fails because there is no class hierarchy relationship between the 3975 // vtable's class and "the new class". 3976 3977 old_constants->set_pool_holder(scratch_class()); 3978 #endif 3979 3980 // track number of methods that are EMCP for add_previous_version() call below 3981 int emcp_method_count = check_methods_and_mark_as_obsolete(); 3982 transfer_old_native_function_registrations(the_class); 3983 3984 // The class file bytes from before any retransformable agents mucked 3985 // with them was cached on the scratch class, move to the_class. 3986 // Note: we still want to do this if nothing needed caching since it 3987 // should get cleared in the_class too. 3988 if (the_class->get_cached_class_file_bytes() == 0) { 3989 // the_class doesn't have a cache yet so copy it 3990 the_class->set_cached_class_file(scratch_class->get_cached_class_file()); 3991 } 3992 else if (scratch_class->get_cached_class_file_bytes() != 3993 the_class->get_cached_class_file_bytes()) { 3994 // The same class can be present twice in the scratch classes list or there 3995 // are multiple concurrent RetransformClasses calls on different threads. 3996 // In such cases we have to deallocate scratch_class cached_class_file_bytes. 3997 os::free(scratch_class->get_cached_class_file_bytes()); 3998 } 3999 4000 // NULL out in scratch class to not delete twice. The class to be redefined 4001 // always owns these bytes. 4002 scratch_class->set_cached_class_file(NULL); 4003 4004 // Replace inner_classes 4005 Array<u2>* old_inner_classes = the_class->inner_classes(); 4006 the_class->set_inner_classes(scratch_class->inner_classes()); 4007 scratch_class->set_inner_classes(old_inner_classes); 4008 4009 // Initialize the vtable and interface table after 4010 // methods have been rewritten 4011 { 4012 ResourceMark rm(THREAD); 4013 // no exception should happen here since we explicitly 4014 // do not check loader constraints. 4015 // compare_and_normalize_class_versions has already checked: 4016 // - classloaders unchanged, signatures unchanged 4017 // - all instanceKlasses for redefined classes reused & contents updated 4018 the_class->vtable()->initialize_vtable(false, THREAD); 4019 the_class->itable()->initialize_itable(false, THREAD); 4020 assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())), "redefine exception"); 4021 } 4022 4023 // Leave arrays of jmethodIDs and itable index cache unchanged 4024 4025 // Copy the "source file name" attribute from new class version 4026 the_class->set_source_file_name_index( 4027 scratch_class->source_file_name_index()); 4028 4029 // Copy the "source debug extension" attribute from new class version 4030 the_class->set_source_debug_extension( 4031 scratch_class->source_debug_extension(), 4032 scratch_class->source_debug_extension() == NULL ? 0 : 4033 (int)strlen(scratch_class->source_debug_extension())); 4034 4035 // Use of javac -g could be different in the old and the new 4036 if (scratch_class->access_flags().has_localvariable_table() != 4037 the_class->access_flags().has_localvariable_table()) { 4038 4039 AccessFlags flags = the_class->access_flags(); 4040 if (scratch_class->access_flags().has_localvariable_table()) { 4041 flags.set_has_localvariable_table(); 4042 } else { 4043 flags.clear_has_localvariable_table(); 4044 } 4045 the_class->set_access_flags(flags); 4046 } 4047 4048 swap_annotations(the_class, scratch_class); 4049 4050 // Replace minor version number of class file 4051 u2 old_minor_version = the_class->minor_version(); 4052 the_class->set_minor_version(scratch_class->minor_version()); 4053 scratch_class->set_minor_version(old_minor_version); 4054 4055 // Replace major version number of class file 4056 u2 old_major_version = the_class->major_version(); 4057 the_class->set_major_version(scratch_class->major_version()); 4058 scratch_class->set_major_version(old_major_version); 4059 4060 // Replace CP indexes for class and name+type of enclosing method 4061 u2 old_class_idx = the_class->enclosing_method_class_index(); 4062 u2 old_method_idx = the_class->enclosing_method_method_index(); 4063 the_class->set_enclosing_method_indices( 4064 scratch_class->enclosing_method_class_index(), 4065 scratch_class->enclosing_method_method_index()); 4066 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx); 4067 4068 the_class->set_has_been_redefined(); 4069 4070 // keep track of previous versions of this class 4071 the_class->add_previous_version(scratch_class, emcp_method_count); 4072 4073 RC_TIMER_STOP(_timer_rsc_phase1); 4074 RC_TIMER_START(_timer_rsc_phase2); 4075 4076 // Adjust constantpool caches and vtables for all classes 4077 // that reference methods of the evolved class. 4078 AdjustCpoolCacheAndVtable adjust_cpool_cache_and_vtable(THREAD); 4079 ClassLoaderDataGraph::classes_do(&adjust_cpool_cache_and_vtable); 4080 4081 // JSR-292 support 4082 MemberNameTable* mnt = the_class->member_names(); 4083 if (mnt != NULL) { 4084 bool trace_name_printed = false; 4085 mnt->adjust_method_entries(the_class(), &trace_name_printed); 4086 } 4087 4088 // Fix Resolution Error table also to remove old constant pools 4089 SystemDictionary::delete_resolution_error(old_constants); 4090 4091 if (the_class->oop_map_cache() != NULL) { 4092 // Flush references to any obsolete methods from the oop map cache 4093 // so that obsolete methods are not pinned. 4094 the_class->oop_map_cache()->flush_obsolete_entries(); 4095 } 4096 4097 // increment the classRedefinedCount field in the_class and in any 4098 // direct and indirect subclasses of the_class 4099 increment_class_counter((InstanceKlass *)the_class(), THREAD); 4100 4101 // RC_TRACE macro has an embedded ResourceMark 4102 RC_TRACE_WITH_THREAD(0x00000001, THREAD, 4103 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)", 4104 the_class->external_name(), 4105 java_lang_Class::classRedefinedCount(the_class_mirror), 4106 os::available_memory() >> 10)); 4107 4108 RC_TIMER_STOP(_timer_rsc_phase2); 4109 } // end redefine_single_class() 4110 4111 4112 // Increment the classRedefinedCount field in the specific InstanceKlass 4113 // and in all direct and indirect subclasses. 4114 void VM_RedefineClasses::increment_class_counter(InstanceKlass *ik, TRAPS) { 4115 oop class_mirror = ik->java_mirror(); 4116 Klass* class_oop = java_lang_Class::as_Klass(class_mirror); 4117 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1; 4118 java_lang_Class::set_classRedefinedCount(class_mirror, new_count); 4119 4120 if (class_oop != _the_class_oop) { 4121 // _the_class_oop count is printed at end of redefine_single_class() 4122 RC_TRACE_WITH_THREAD(0x00000008, THREAD, 4123 ("updated count in subclass=%s to %d", ik->external_name(), new_count)); 4124 } 4125 4126 for (Klass *subk = ik->subklass(); subk != NULL; 4127 subk = subk->next_sibling()) { 4128 if (subk->oop_is_instance()) { 4129 // Only update instanceKlasses 4130 InstanceKlass *subik = (InstanceKlass*)subk; 4131 // recursively do subclasses of the current subclass 4132 increment_class_counter(subik, THREAD); 4133 } 4134 } 4135 } 4136 4137 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) { 4138 bool no_old_methods = true; // be optimistic 4139 4140 // Both array and instance classes have vtables. 4141 // a vtable should never contain old or obsolete methods 4142 ResourceMark rm(_thread); 4143 if (k->vtable_length() > 0 && 4144 !k->vtable()->check_no_old_or_obsolete_entries()) { 4145 if (RC_TRACE_ENABLED(0x00004000)) { 4146 RC_TRACE_WITH_THREAD(0x00004000, _thread, 4147 ("klassVtable::check_no_old_or_obsolete_entries failure" 4148 " -- OLD or OBSOLETE method found -- class: %s", 4149 k->signature_name())); 4150 k->vtable()->dump_vtable(); 4151 } 4152 no_old_methods = false; 4153 } 4154 4155 if (k->oop_is_instance()) { 4156 HandleMark hm(_thread); 4157 InstanceKlass *ik = InstanceKlass::cast(k); 4158 4159 // an itable should never contain old or obsolete methods 4160 if (ik->itable_length() > 0 && 4161 !ik->itable()->check_no_old_or_obsolete_entries()) { 4162 if (RC_TRACE_ENABLED(0x00004000)) { 4163 RC_TRACE_WITH_THREAD(0x00004000, _thread, 4164 ("klassItable::check_no_old_or_obsolete_entries failure" 4165 " -- OLD or OBSOLETE method found -- class: %s", 4166 ik->signature_name())); 4167 ik->itable()->dump_itable(); 4168 } 4169 no_old_methods = false; 4170 } 4171 4172 // the constant pool cache should never contain non-deleted old or obsolete methods 4173 if (ik->constants() != NULL && 4174 ik->constants()->cache() != NULL && 4175 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) { 4176 if (RC_TRACE_ENABLED(0x00004000)) { 4177 RC_TRACE_WITH_THREAD(0x00004000, _thread, 4178 ("cp-cache::check_no_old_or_obsolete_entries failure" 4179 " -- OLD or OBSOLETE method found -- class: %s", 4180 ik->signature_name())); 4181 ik->constants()->cache()->dump_cache(); 4182 } 4183 no_old_methods = false; 4184 } 4185 } 4186 4187 // print and fail guarantee if old methods are found. 4188 if (!no_old_methods) { 4189 if (RC_TRACE_ENABLED(0x00004000)) { 4190 dump_methods(); 4191 } else { 4192 tty->print_cr("INFO: use the '-XX:TraceRedefineClasses=16384' option " 4193 "to see more info about the following guarantee() failure."); 4194 } 4195 guarantee(false, "OLD and/or OBSOLETE method(s) found"); 4196 } 4197 } 4198 4199 4200 void VM_RedefineClasses::dump_methods() { 4201 int j; 4202 RC_TRACE(0x00004000, ("_old_methods --")); 4203 for (j = 0; j < _old_methods->length(); ++j) { 4204 Method* m = _old_methods->at(j); 4205 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index())); 4206 m->access_flags().print_on(tty); 4207 tty->print(" -- "); 4208 m->print_name(tty); 4209 tty->cr(); 4210 } 4211 RC_TRACE(0x00004000, ("_new_methods --")); 4212 for (j = 0; j < _new_methods->length(); ++j) { 4213 Method* m = _new_methods->at(j); 4214 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index())); 4215 m->access_flags().print_on(tty); 4216 tty->print(" -- "); 4217 m->print_name(tty); 4218 tty->cr(); 4219 } 4220 RC_TRACE(0x00004000, ("_matching_(old/new)_methods --")); 4221 for (j = 0; j < _matching_methods_length; ++j) { 4222 Method* m = _matching_old_methods[j]; 4223 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index())); 4224 m->access_flags().print_on(tty); 4225 tty->print(" -- "); 4226 m->print_name(tty); 4227 tty->cr(); 4228 m = _matching_new_methods[j]; 4229 RC_TRACE_NO_CR(0x00004000, (" (%5d) ", m->vtable_index())); 4230 m->access_flags().print_on(tty); 4231 tty->cr(); 4232 } 4233 RC_TRACE(0x00004000, ("_deleted_methods --")); 4234 for (j = 0; j < _deleted_methods_length; ++j) { 4235 Method* m = _deleted_methods[j]; 4236 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index())); 4237 m->access_flags().print_on(tty); 4238 tty->print(" -- "); 4239 m->print_name(tty); 4240 tty->cr(); 4241 } 4242 RC_TRACE(0x00004000, ("_added_methods --")); 4243 for (j = 0; j < _added_methods_length; ++j) { 4244 Method* m = _added_methods[j]; 4245 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index())); 4246 m->access_flags().print_on(tty); 4247 tty->print(" -- "); 4248 m->print_name(tty); 4249 tty->cr(); 4250 } 4251 }