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 "gc/shared/gcLocker.hpp" 32 #include "interpreter/oopMapCache.hpp" 33 #include "interpreter/rewriter.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 #include "utilities/events.hpp" 47 48 Array<Method*>* VM_RedefineClasses::_old_methods = NULL; 49 Array<Method*>* VM_RedefineClasses::_new_methods = NULL; 50 Method** VM_RedefineClasses::_matching_old_methods = NULL; 51 Method** VM_RedefineClasses::_matching_new_methods = NULL; 52 Method** VM_RedefineClasses::_deleted_methods = NULL; 53 Method** VM_RedefineClasses::_added_methods = NULL; 54 int VM_RedefineClasses::_matching_methods_length = 0; 55 int VM_RedefineClasses::_deleted_methods_length = 0; 56 int VM_RedefineClasses::_added_methods_length = 0; 57 Klass* VM_RedefineClasses::_the_class_oop = NULL; 58 59 60 VM_RedefineClasses::VM_RedefineClasses(jint class_count, 61 const jvmtiClassDefinition *class_defs, 62 JvmtiClassLoadKind class_load_kind) { 63 _class_count = class_count; 64 _class_defs = class_defs; 65 _class_load_kind = class_load_kind; 66 _res = JVMTI_ERROR_NONE; 67 } 68 69 bool VM_RedefineClasses::doit_prologue() { 70 if (_class_count == 0) { 71 _res = JVMTI_ERROR_NONE; 72 return false; 73 } 74 if (_class_defs == NULL) { 75 _res = JVMTI_ERROR_NULL_POINTER; 76 return false; 77 } 78 for (int i = 0; i < _class_count; i++) { 79 if (_class_defs[i].klass == NULL) { 80 _res = JVMTI_ERROR_INVALID_CLASS; 81 return false; 82 } 83 if (_class_defs[i].class_byte_count == 0) { 84 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT; 85 return false; 86 } 87 if (_class_defs[i].class_bytes == NULL) { 88 _res = JVMTI_ERROR_NULL_POINTER; 89 return false; 90 } 91 } 92 93 // Start timer after all the sanity checks; not quite accurate, but 94 // better than adding a bunch of stop() calls. 95 RC_TIMER_START(_timer_vm_op_prologue); 96 97 // We first load new class versions in the prologue, because somewhere down the 98 // call chain it is required that the current thread is a Java thread. 99 _res = load_new_class_versions(Thread::current()); 100 if (_res != JVMTI_ERROR_NONE) { 101 // free any successfully created classes, since none are redefined 102 for (int i = 0; i < _class_count; i++) { 103 if (_scratch_classes[i] != NULL) { 104 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data(); 105 // Free the memory for this class at class unloading time. Not before 106 // because CMS might think this is still live. 107 cld->add_to_deallocate_list((InstanceKlass*)_scratch_classes[i]); 108 } 109 } 110 // Free os::malloc allocated memory in load_new_class_version. 111 os::free(_scratch_classes); 112 RC_TIMER_STOP(_timer_vm_op_prologue); 113 return false; 114 } 115 116 RC_TIMER_STOP(_timer_vm_op_prologue); 117 return true; 118 } 119 120 void VM_RedefineClasses::doit() { 121 Thread *thread = Thread::current(); 122 123 if (UseSharedSpaces) { 124 // Sharing is enabled so we remap the shared readonly space to 125 // shared readwrite, private just in case we need to redefine 126 // a shared class. We do the remap during the doit() phase of 127 // the safepoint to be safer. 128 if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) { 129 RC_TRACE_WITH_THREAD(0x00000001, thread, 130 ("failed to remap shared readonly space to readwrite, private")); 131 _res = JVMTI_ERROR_INTERNAL; 132 return; 133 } 134 } 135 136 // Mark methods seen on stack and everywhere else so old methods are not 137 // cleaned up if they're on the stack. 138 MetadataOnStackMark md_on_stack(true); 139 HandleMark hm(thread); // make sure any handles created are deleted 140 // before the stack walk again. 141 142 for (int i = 0; i < _class_count; i++) { 143 redefine_single_class(_class_defs[i].klass, _scratch_classes[i], thread); 144 } 145 146 // Clean out MethodData pointing to old Method* 147 // Have to do this after all classes are redefined and all methods that 148 // are redefined are marked as old. 149 MethodDataCleaner clean_weak_method_links; 150 ClassLoaderDataGraph::classes_do(&clean_weak_method_links); 151 152 // Disable any dependent concurrent compilations 153 SystemDictionary::notice_modification(); 154 155 // Set flag indicating that some invariants are no longer true. 156 // See jvmtiExport.hpp for detailed explanation. 157 JvmtiExport::set_has_redefined_a_class(); 158 159 // check_class() is optionally called for product bits, but is 160 // always called for non-product bits. 161 #ifdef PRODUCT 162 if (RC_TRACE_ENABLED(0x00004000)) { 163 #endif 164 RC_TRACE_WITH_THREAD(0x00004000, thread, ("calling check_class")); 165 CheckClass check_class(thread); 166 ClassLoaderDataGraph::classes_do(&check_class); 167 #ifdef PRODUCT 168 } 169 #endif 170 } 171 172 void VM_RedefineClasses::doit_epilogue() { 173 // Free os::malloc allocated memory. 174 os::free(_scratch_classes); 175 176 // Reset the_class_oop to null for error printing. 177 _the_class_oop = NULL; 178 179 if (RC_TRACE_ENABLED(0x00000004)) { 180 // Used to have separate timers for "doit" and "all", but the timer 181 // overhead skewed the measurements. 182 jlong doit_time = _timer_rsc_phase1.milliseconds() + 183 _timer_rsc_phase2.milliseconds(); 184 jlong all_time = _timer_vm_op_prologue.milliseconds() + doit_time; 185 186 RC_TRACE(0x00000004, ("vm_op: all=" UINT64_FORMAT 187 " prologue=" UINT64_FORMAT " doit=" UINT64_FORMAT, all_time, 188 _timer_vm_op_prologue.milliseconds(), doit_time)); 189 RC_TRACE(0x00000004, 190 ("redefine_single_class: phase1=" UINT64_FORMAT " phase2=" UINT64_FORMAT, 191 _timer_rsc_phase1.milliseconds(), _timer_rsc_phase2.milliseconds())); 192 } 193 } 194 195 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) { 196 // classes for primitives cannot be redefined 197 if (java_lang_Class::is_primitive(klass_mirror)) { 198 return false; 199 } 200 Klass* the_class_oop = java_lang_Class::as_Klass(klass_mirror); 201 // classes for arrays cannot be redefined 202 if (the_class_oop == NULL || !the_class_oop->oop_is_instance()) { 203 return false; 204 } 205 return true; 206 } 207 208 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p 209 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For 210 // direct CP entries, there is just the current entry to append. For 211 // indirect and double-indirect CP entries, there are zero or more 212 // referenced CP entries along with the current entry to append. 213 // Indirect and double-indirect CP entries are handled by recursive 214 // calls to append_entry() as needed. The referenced CP entries are 215 // always appended to *merge_cp_p before the referee CP entry. These 216 // referenced CP entries may already exist in *merge_cp_p in which case 217 // there is nothing extra to append and only the current entry is 218 // appended. 219 void VM_RedefineClasses::append_entry(constantPoolHandle scratch_cp, 220 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, 221 TRAPS) { 222 223 // append is different depending on entry tag type 224 switch (scratch_cp->tag_at(scratch_i).value()) { 225 226 // The old verifier is implemented outside the VM. It loads classes, 227 // but does not resolve constant pool entries directly so we never 228 // see Class entries here with the old verifier. Similarly the old 229 // verifier does not like Class entries in the input constant pool. 230 // The split-verifier is implemented in the VM so it can optionally 231 // and directly resolve constant pool entries to load classes. The 232 // split-verifier can accept either Class entries or UnresolvedClass 233 // entries in the input constant pool. We revert the appended copy 234 // back to UnresolvedClass so that either verifier will be happy 235 // with the constant pool entry. 236 case JVM_CONSTANT_Class: 237 { 238 // revert the copy to JVM_CONSTANT_UnresolvedClass 239 (*merge_cp_p)->unresolved_klass_at_put(*merge_cp_length_p, 240 scratch_cp->klass_name_at(scratch_i)); 241 242 if (scratch_i != *merge_cp_length_p) { 243 // The new entry in *merge_cp_p is at a different index than 244 // the new entry in scratch_cp so we need to map the index values. 245 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 246 } 247 (*merge_cp_length_p)++; 248 } break; 249 250 // these are direct CP entries so they can be directly appended, 251 // but double and long take two constant pool entries 252 case JVM_CONSTANT_Double: // fall through 253 case JVM_CONSTANT_Long: 254 { 255 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p, 256 THREAD); 257 258 if (scratch_i != *merge_cp_length_p) { 259 // The new entry in *merge_cp_p is at a different index than 260 // the new entry in scratch_cp so we need to map the index values. 261 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 262 } 263 (*merge_cp_length_p) += 2; 264 } break; 265 266 // these are direct CP entries so they can be directly appended 267 case JVM_CONSTANT_Float: // fall through 268 case JVM_CONSTANT_Integer: // fall through 269 case JVM_CONSTANT_Utf8: // fall through 270 271 // This was an indirect CP entry, but it has been changed into 272 // Symbol*s so this entry can be directly appended. 273 case JVM_CONSTANT_String: // fall through 274 275 // These were indirect CP entries, but they have been changed into 276 // Symbol*s so these entries can be directly appended. 277 case JVM_CONSTANT_UnresolvedClass: // fall through 278 { 279 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p, 280 THREAD); 281 282 if (scratch_i != *merge_cp_length_p) { 283 // The new entry in *merge_cp_p is at a different index than 284 // the new entry in scratch_cp so we need to map the index values. 285 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 286 } 287 (*merge_cp_length_p)++; 288 } break; 289 290 // this is an indirect CP entry so it needs special handling 291 case JVM_CONSTANT_NameAndType: 292 { 293 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i); 294 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p, 295 merge_cp_length_p, THREAD); 296 297 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i); 298 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i, 299 merge_cp_p, merge_cp_length_p, 300 THREAD); 301 302 // If the referenced entries already exist in *merge_cp_p, then 303 // both new_name_ref_i and new_signature_ref_i will both be 0. 304 // In that case, all we are appending is the current entry. 305 if (new_name_ref_i != name_ref_i) { 306 RC_TRACE(0x00080000, 307 ("NameAndType entry@%d name_ref_index change: %d to %d", 308 *merge_cp_length_p, name_ref_i, new_name_ref_i)); 309 } 310 if (new_signature_ref_i != signature_ref_i) { 311 RC_TRACE(0x00080000, 312 ("NameAndType entry@%d signature_ref_index change: %d to %d", 313 *merge_cp_length_p, signature_ref_i, new_signature_ref_i)); 314 } 315 316 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p, 317 new_name_ref_i, new_signature_ref_i); 318 if (scratch_i != *merge_cp_length_p) { 319 // The new entry in *merge_cp_p is at a different index than 320 // the new entry in scratch_cp so we need to map the index values. 321 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 322 } 323 (*merge_cp_length_p)++; 324 } break; 325 326 // this is a double-indirect CP entry so it needs special handling 327 case JVM_CONSTANT_Fieldref: // fall through 328 case JVM_CONSTANT_InterfaceMethodref: // fall through 329 case JVM_CONSTANT_Methodref: 330 { 331 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i); 332 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i, 333 merge_cp_p, merge_cp_length_p, THREAD); 334 335 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i); 336 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i, 337 merge_cp_p, merge_cp_length_p, THREAD); 338 339 const char *entry_name; 340 switch (scratch_cp->tag_at(scratch_i).value()) { 341 case JVM_CONSTANT_Fieldref: 342 entry_name = "Fieldref"; 343 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i, 344 new_name_and_type_ref_i); 345 break; 346 case JVM_CONSTANT_InterfaceMethodref: 347 entry_name = "IFMethodref"; 348 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p, 349 new_klass_ref_i, new_name_and_type_ref_i); 350 break; 351 case JVM_CONSTANT_Methodref: 352 entry_name = "Methodref"; 353 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i, 354 new_name_and_type_ref_i); 355 break; 356 default: 357 guarantee(false, "bad switch"); 358 break; 359 } 360 361 if (klass_ref_i != new_klass_ref_i) { 362 RC_TRACE(0x00080000, ("%s entry@%d class_index changed: %d to %d", 363 entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i)); 364 } 365 if (name_and_type_ref_i != new_name_and_type_ref_i) { 366 RC_TRACE(0x00080000, 367 ("%s entry@%d name_and_type_index changed: %d to %d", 368 entry_name, *merge_cp_length_p, name_and_type_ref_i, 369 new_name_and_type_ref_i)); 370 } 371 372 if (scratch_i != *merge_cp_length_p) { 373 // The new entry in *merge_cp_p is at a different index than 374 // the new entry in scratch_cp so we need to map the index values. 375 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 376 } 377 (*merge_cp_length_p)++; 378 } break; 379 380 // this is an indirect CP entry so it needs special handling 381 case JVM_CONSTANT_MethodType: 382 { 383 int ref_i = scratch_cp->method_type_index_at(scratch_i); 384 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p, 385 merge_cp_length_p, THREAD); 386 if (new_ref_i != ref_i) { 387 RC_TRACE(0x00080000, 388 ("MethodType entry@%d ref_index change: %d to %d", 389 *merge_cp_length_p, ref_i, new_ref_i)); 390 } 391 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i); 392 if (scratch_i != *merge_cp_length_p) { 393 // The new entry in *merge_cp_p is at a different index than 394 // the new entry in scratch_cp so we need to map the index values. 395 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 396 } 397 (*merge_cp_length_p)++; 398 } break; 399 400 // this is an indirect CP entry so it needs special handling 401 case JVM_CONSTANT_MethodHandle: 402 { 403 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i); 404 int ref_i = scratch_cp->method_handle_index_at(scratch_i); 405 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p, 406 merge_cp_length_p, THREAD); 407 if (new_ref_i != ref_i) { 408 RC_TRACE(0x00080000, 409 ("MethodHandle entry@%d ref_index change: %d to %d", 410 *merge_cp_length_p, ref_i, new_ref_i)); 411 } 412 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i); 413 if (scratch_i != *merge_cp_length_p) { 414 // The new entry in *merge_cp_p is at a different index than 415 // the new entry in scratch_cp so we need to map the index values. 416 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 417 } 418 (*merge_cp_length_p)++; 419 } break; 420 421 // this is an indirect CP entry so it needs special handling 422 case JVM_CONSTANT_InvokeDynamic: 423 { 424 // Index of the bootstrap specifier in the operands array 425 int old_bs_i = scratch_cp->invoke_dynamic_bootstrap_specifier_index(scratch_i); 426 int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p, 427 merge_cp_length_p, THREAD); 428 // The bootstrap method NameAndType_info index 429 int old_ref_i = scratch_cp->invoke_dynamic_name_and_type_ref_index_at(scratch_i); 430 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p, 431 merge_cp_length_p, THREAD); 432 if (new_bs_i != old_bs_i) { 433 RC_TRACE(0x00080000, 434 ("InvokeDynamic entry@%d bootstrap_method_attr_index change: %d to %d", 435 *merge_cp_length_p, old_bs_i, new_bs_i)); 436 } 437 if (new_ref_i != old_ref_i) { 438 RC_TRACE(0x00080000, 439 ("InvokeDynamic entry@%d name_and_type_index change: %d to %d", 440 *merge_cp_length_p, old_ref_i, new_ref_i)); 441 } 442 443 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i); 444 if (scratch_i != *merge_cp_length_p) { 445 // The new entry in *merge_cp_p is at a different index than 446 // the new entry in scratch_cp so we need to map the index values. 447 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 448 } 449 (*merge_cp_length_p)++; 450 } break; 451 452 // At this stage, Class or UnresolvedClass could be here, but not 453 // ClassIndex 454 case JVM_CONSTANT_ClassIndex: // fall through 455 456 // Invalid is used as the tag for the second constant pool entry 457 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should 458 // not be seen by itself. 459 case JVM_CONSTANT_Invalid: // fall through 460 461 // At this stage, String could be here, but not StringIndex 462 case JVM_CONSTANT_StringIndex: // fall through 463 464 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be 465 // here 466 case JVM_CONSTANT_UnresolvedClassInError: // fall through 467 468 default: 469 { 470 // leave a breadcrumb 471 jbyte bad_value = scratch_cp->tag_at(scratch_i).value(); 472 ShouldNotReachHere(); 473 } break; 474 } // end switch tag value 475 } // end append_entry() 476 477 478 int VM_RedefineClasses::find_or_append_indirect_entry(constantPoolHandle scratch_cp, 479 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) { 480 481 int new_ref_i = ref_i; 482 bool match = (ref_i < *merge_cp_length_p) && 483 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i, THREAD); 484 485 if (!match) { 486 // forward reference in *merge_cp_p or not a direct match 487 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p, THREAD); 488 if (found_i != 0) { 489 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree"); 490 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry. 491 new_ref_i = found_i; 492 map_index(scratch_cp, ref_i, found_i); 493 } else { 494 // no match found so we have to append this entry to *merge_cp_p 495 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p, THREAD); 496 // The above call to append_entry() can only append one entry 497 // so the post call query of *merge_cp_length_p is only for 498 // the sake of consistency. 499 new_ref_i = *merge_cp_length_p - 1; 500 } 501 } 502 503 return new_ref_i; 504 } // end find_or_append_indirect_entry() 505 506 507 // Append a bootstrap specifier into the merge_cp operands that is semantically equal 508 // to the scratch_cp operands bootstrap specifier passed by the old_bs_i index. 509 // Recursively append new merge_cp entries referenced by the new bootstrap specifier. 510 void VM_RedefineClasses::append_operand(constantPoolHandle scratch_cp, int old_bs_i, 511 constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) { 512 513 int old_ref_i = scratch_cp->operand_bootstrap_method_ref_index_at(old_bs_i); 514 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p, 515 merge_cp_length_p, THREAD); 516 if (new_ref_i != old_ref_i) { 517 RC_TRACE(0x00080000, 518 ("operands entry@%d bootstrap method ref_index change: %d to %d", 519 _operands_cur_length, old_ref_i, new_ref_i)); 520 } 521 522 Array<u2>* merge_ops = (*merge_cp_p)->operands(); 523 int new_bs_i = _operands_cur_length; 524 // We have _operands_cur_length == 0 when the merge_cp operands is empty yet. 525 // However, the operand_offset_at(0) was set in the extend_operands() call. 526 int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0) 527 : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1); 528 int argc = scratch_cp->operand_argument_count_at(old_bs_i); 529 530 ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base); 531 merge_ops->at_put(new_base++, new_ref_i); 532 merge_ops->at_put(new_base++, argc); 533 534 for (int i = 0; i < argc; i++) { 535 int old_arg_ref_i = scratch_cp->operand_argument_index_at(old_bs_i, i); 536 int new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p, 537 merge_cp_length_p, THREAD); 538 merge_ops->at_put(new_base++, new_arg_ref_i); 539 if (new_arg_ref_i != old_arg_ref_i) { 540 RC_TRACE(0x00080000, 541 ("operands entry@%d bootstrap method argument ref_index change: %d to %d", 542 _operands_cur_length, old_arg_ref_i, new_arg_ref_i)); 543 } 544 } 545 if (old_bs_i != _operands_cur_length) { 546 // The bootstrap specifier in *merge_cp_p is at a different index than 547 // that in scratch_cp so we need to map the index values. 548 map_operand_index(old_bs_i, new_bs_i); 549 } 550 _operands_cur_length++; 551 } // end append_operand() 552 553 554 int VM_RedefineClasses::find_or_append_operand(constantPoolHandle scratch_cp, 555 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) { 556 557 int new_bs_i = old_bs_i; // bootstrap specifier index 558 bool match = (old_bs_i < _operands_cur_length) && 559 scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i, THREAD); 560 561 if (!match) { 562 // forward reference in *merge_cp_p or not a direct match 563 int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p, 564 _operands_cur_length, THREAD); 565 if (found_i != -1) { 566 guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree"); 567 // found a matching operand somewhere else in *merge_cp_p so just need a mapping 568 new_bs_i = found_i; 569 map_operand_index(old_bs_i, found_i); 570 } else { 571 // no match found so we have to append this bootstrap specifier to *merge_cp_p 572 append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p, THREAD); 573 new_bs_i = _operands_cur_length - 1; 574 } 575 } 576 return new_bs_i; 577 } // end find_or_append_operand() 578 579 580 void VM_RedefineClasses::finalize_operands_merge(constantPoolHandle merge_cp, TRAPS) { 581 if (merge_cp->operands() == NULL) { 582 return; 583 } 584 // Shrink the merge_cp operands 585 merge_cp->shrink_operands(_operands_cur_length, CHECK); 586 587 if (RC_TRACE_ENABLED(0x00040000)) { 588 // don't want to loop unless we are tracing 589 int count = 0; 590 for (int i = 1; i < _operands_index_map_p->length(); i++) { 591 int value = _operands_index_map_p->at(i); 592 if (value != -1) { 593 RC_TRACE_WITH_THREAD(0x00040000, THREAD, 594 ("operands_index_map[%d]: old=%d new=%d", count, i, value)); 595 count++; 596 } 597 } 598 } 599 // Clean-up 600 _operands_index_map_p = NULL; 601 _operands_cur_length = 0; 602 _operands_index_map_count = 0; 603 } // end finalize_operands_merge() 604 605 606 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions( 607 instanceKlassHandle the_class, 608 instanceKlassHandle scratch_class) { 609 int i; 610 611 // Check superclasses, or rather their names, since superclasses themselves can be 612 // requested to replace. 613 // Check for NULL superclass first since this might be java.lang.Object 614 if (the_class->super() != scratch_class->super() && 615 (the_class->super() == NULL || scratch_class->super() == NULL || 616 the_class->super()->name() != 617 scratch_class->super()->name())) { 618 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 619 } 620 621 // Check if the number, names and order of directly implemented interfaces are the same. 622 // I think in principle we should just check if the sets of names of directly implemented 623 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the 624 // .java file, also changes in .class file) should not matter. However, comparing sets is 625 // technically a bit more difficult, and, more importantly, I am not sure at present that the 626 // order of interfaces does not matter on the implementation level, i.e. that the VM does not 627 // rely on it somewhere. 628 Array<Klass*>* k_interfaces = the_class->local_interfaces(); 629 Array<Klass*>* k_new_interfaces = scratch_class->local_interfaces(); 630 int n_intfs = k_interfaces->length(); 631 if (n_intfs != k_new_interfaces->length()) { 632 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 633 } 634 for (i = 0; i < n_intfs; i++) { 635 if (k_interfaces->at(i)->name() != 636 k_new_interfaces->at(i)->name()) { 637 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 638 } 639 } 640 641 // Check whether class is in the error init state. 642 if (the_class->is_in_error_state()) { 643 // TBD #5057930: special error code is needed in 1.6 644 return JVMTI_ERROR_INVALID_CLASS; 645 } 646 647 // Check whether class modifiers are the same. 648 jushort old_flags = (jushort) the_class->access_flags().get_flags(); 649 jushort new_flags = (jushort) scratch_class->access_flags().get_flags(); 650 if (old_flags != new_flags) { 651 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED; 652 } 653 654 // Check if the number, names, types and order of fields declared in these classes 655 // are the same. 656 JavaFieldStream old_fs(the_class); 657 JavaFieldStream new_fs(scratch_class); 658 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) { 659 // access 660 old_flags = old_fs.access_flags().as_short(); 661 new_flags = new_fs.access_flags().as_short(); 662 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) { 663 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 664 } 665 // offset 666 if (old_fs.offset() != new_fs.offset()) { 667 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 668 } 669 // name and signature 670 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index()); 671 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index()); 672 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index()); 673 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index()); 674 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) { 675 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 676 } 677 } 678 679 // If both streams aren't done then we have a differing number of 680 // fields. 681 if (!old_fs.done() || !new_fs.done()) { 682 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 683 } 684 685 // Do a parallel walk through the old and new methods. Detect 686 // cases where they match (exist in both), have been added in 687 // the new methods, or have been deleted (exist only in the 688 // old methods). The class file parser places methods in order 689 // by method name, but does not order overloaded methods by 690 // signature. In order to determine what fate befell the methods, 691 // this code places the overloaded new methods that have matching 692 // old methods in the same order as the old methods and places 693 // new overloaded methods at the end of overloaded methods of 694 // that name. The code for this order normalization is adapted 695 // from the algorithm used in InstanceKlass::find_method(). 696 // Since we are swapping out of order entries as we find them, 697 // we only have to search forward through the overloaded methods. 698 // Methods which are added and have the same name as an existing 699 // method (but different signature) will be put at the end of 700 // the methods with that name, and the name mismatch code will 701 // handle them. 702 Array<Method*>* k_old_methods(the_class->methods()); 703 Array<Method*>* k_new_methods(scratch_class->methods()); 704 int n_old_methods = k_old_methods->length(); 705 int n_new_methods = k_new_methods->length(); 706 Thread* thread = Thread::current(); 707 708 int ni = 0; 709 int oi = 0; 710 while (true) { 711 Method* k_old_method; 712 Method* k_new_method; 713 enum { matched, added, deleted, undetermined } method_was = undetermined; 714 715 if (oi >= n_old_methods) { 716 if (ni >= n_new_methods) { 717 break; // we've looked at everything, done 718 } 719 // New method at the end 720 k_new_method = k_new_methods->at(ni); 721 method_was = added; 722 } else if (ni >= n_new_methods) { 723 // Old method, at the end, is deleted 724 k_old_method = k_old_methods->at(oi); 725 method_was = deleted; 726 } else { 727 // There are more methods in both the old and new lists 728 k_old_method = k_old_methods->at(oi); 729 k_new_method = k_new_methods->at(ni); 730 if (k_old_method->name() != k_new_method->name()) { 731 // Methods are sorted by method name, so a mismatch means added 732 // or deleted 733 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) { 734 method_was = added; 735 } else { 736 method_was = deleted; 737 } 738 } else if (k_old_method->signature() == k_new_method->signature()) { 739 // Both the name and signature match 740 method_was = matched; 741 } else { 742 // The name matches, but the signature doesn't, which means we have to 743 // search forward through the new overloaded methods. 744 int nj; // outside the loop for post-loop check 745 for (nj = ni + 1; nj < n_new_methods; nj++) { 746 Method* m = k_new_methods->at(nj); 747 if (k_old_method->name() != m->name()) { 748 // reached another method name so no more overloaded methods 749 method_was = deleted; 750 break; 751 } 752 if (k_old_method->signature() == m->signature()) { 753 // found a match so swap the methods 754 k_new_methods->at_put(ni, m); 755 k_new_methods->at_put(nj, k_new_method); 756 k_new_method = m; 757 method_was = matched; 758 break; 759 } 760 } 761 762 if (nj >= n_new_methods) { 763 // reached the end without a match; so method was deleted 764 method_was = deleted; 765 } 766 } 767 } 768 769 switch (method_was) { 770 case matched: 771 // methods match, be sure modifiers do too 772 old_flags = (jushort) k_old_method->access_flags().get_flags(); 773 new_flags = (jushort) k_new_method->access_flags().get_flags(); 774 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) { 775 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED; 776 } 777 { 778 u2 new_num = k_new_method->method_idnum(); 779 u2 old_num = k_old_method->method_idnum(); 780 if (new_num != old_num) { 781 Method* idnum_owner = scratch_class->method_with_idnum(old_num); 782 if (idnum_owner != NULL) { 783 // There is already a method assigned this idnum -- switch them 784 // Take current and original idnum from the new_method 785 idnum_owner->set_method_idnum(new_num); 786 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum()); 787 } 788 // Take current and original idnum from the old_method 789 k_new_method->set_method_idnum(old_num); 790 k_new_method->set_orig_method_idnum(k_old_method->orig_method_idnum()); 791 if (thread->has_pending_exception()) { 792 return JVMTI_ERROR_OUT_OF_MEMORY; 793 } 794 } 795 } 796 RC_TRACE(0x00008000, ("Method matched: new: %s [%d] == old: %s [%d]", 797 k_new_method->name_and_sig_as_C_string(), ni, 798 k_old_method->name_and_sig_as_C_string(), oi)); 799 // advance to next pair of methods 800 ++oi; 801 ++ni; 802 break; 803 case added: 804 // method added, see if it is OK 805 new_flags = (jushort) k_new_method->access_flags().get_flags(); 806 if ((new_flags & JVM_ACC_PRIVATE) == 0 807 // hack: private should be treated as final, but alas 808 || (new_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0 809 ) { 810 // new methods must be private 811 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED; 812 } 813 { 814 u2 num = the_class->next_method_idnum(); 815 if (num == ConstMethod::UNSET_IDNUM) { 816 // cannot add any more methods 817 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED; 818 } 819 u2 new_num = k_new_method->method_idnum(); 820 Method* idnum_owner = scratch_class->method_with_idnum(num); 821 if (idnum_owner != NULL) { 822 // There is already a method assigned this idnum -- switch them 823 // Take current and original idnum from the new_method 824 idnum_owner->set_method_idnum(new_num); 825 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum()); 826 } 827 k_new_method->set_method_idnum(num); 828 k_new_method->set_orig_method_idnum(num); 829 if (thread->has_pending_exception()) { 830 return JVMTI_ERROR_OUT_OF_MEMORY; 831 } 832 } 833 RC_TRACE(0x00008000, ("Method added: new: %s [%d]", 834 k_new_method->name_and_sig_as_C_string(), ni)); 835 ++ni; // advance to next new method 836 break; 837 case deleted: 838 // method deleted, see if it is OK 839 old_flags = (jushort) k_old_method->access_flags().get_flags(); 840 if ((old_flags & JVM_ACC_PRIVATE) == 0 841 // hack: private should be treated as final, but alas 842 || (old_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0 843 ) { 844 // deleted methods must be private 845 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED; 846 } 847 RC_TRACE(0x00008000, ("Method deleted: old: %s [%d]", 848 k_old_method->name_and_sig_as_C_string(), oi)); 849 ++oi; // advance to next old method 850 break; 851 default: 852 ShouldNotReachHere(); 853 } 854 } 855 856 return JVMTI_ERROR_NONE; 857 } 858 859 860 // Find new constant pool index value for old constant pool index value 861 // by seaching the index map. Returns zero (0) if there is no mapped 862 // value for the old constant pool index. 863 int VM_RedefineClasses::find_new_index(int old_index) { 864 if (_index_map_count == 0) { 865 // map is empty so nothing can be found 866 return 0; 867 } 868 869 if (old_index < 1 || old_index >= _index_map_p->length()) { 870 // The old_index is out of range so it is not mapped. This should 871 // not happen in regular constant pool merging use, but it can 872 // happen if a corrupt annotation is processed. 873 return 0; 874 } 875 876 int value = _index_map_p->at(old_index); 877 if (value == -1) { 878 // the old_index is not mapped 879 return 0; 880 } 881 882 return value; 883 } // end find_new_index() 884 885 886 // Find new bootstrap specifier index value for old bootstrap specifier index 887 // value by seaching the index map. Returns unused index (-1) if there is 888 // no mapped value for the old bootstrap specifier index. 889 int VM_RedefineClasses::find_new_operand_index(int old_index) { 890 if (_operands_index_map_count == 0) { 891 // map is empty so nothing can be found 892 return -1; 893 } 894 895 if (old_index == -1 || old_index >= _operands_index_map_p->length()) { 896 // The old_index is out of range so it is not mapped. 897 // This should not happen in regular constant pool merging use. 898 return -1; 899 } 900 901 int value = _operands_index_map_p->at(old_index); 902 if (value == -1) { 903 // the old_index is not mapped 904 return -1; 905 } 906 907 return value; 908 } // end find_new_operand_index() 909 910 911 // Returns true if the current mismatch is due to a resolved/unresolved 912 // class pair. Otherwise, returns false. 913 bool VM_RedefineClasses::is_unresolved_class_mismatch(constantPoolHandle cp1, 914 int index1, constantPoolHandle cp2, int index2) { 915 916 jbyte t1 = cp1->tag_at(index1).value(); 917 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) { 918 return false; // wrong entry type; not our special case 919 } 920 921 jbyte t2 = cp2->tag_at(index2).value(); 922 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) { 923 return false; // wrong entry type; not our special case 924 } 925 926 if (t1 == t2) { 927 return false; // not a mismatch; not our special case 928 } 929 930 char *s1 = cp1->klass_name_at(index1)->as_C_string(); 931 char *s2 = cp2->klass_name_at(index2)->as_C_string(); 932 if (strcmp(s1, s2) != 0) { 933 return false; // strings don't match; not our special case 934 } 935 936 return true; // made it through the gauntlet; this is our special case 937 } // end is_unresolved_class_mismatch() 938 939 940 jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) { 941 942 // For consistency allocate memory using os::malloc wrapper. 943 _scratch_classes = (Klass**) 944 os::malloc(sizeof(Klass*) * _class_count, mtClass); 945 if (_scratch_classes == NULL) { 946 return JVMTI_ERROR_OUT_OF_MEMORY; 947 } 948 // Zero initialize the _scratch_classes array. 949 for (int i = 0; i < _class_count; i++) { 950 _scratch_classes[i] = NULL; 951 } 952 953 ResourceMark rm(THREAD); 954 955 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current()); 956 // state can only be NULL if the current thread is exiting which 957 // should not happen since we're trying to do a RedefineClasses 958 guarantee(state != NULL, "exiting thread calling load_new_class_versions"); 959 for (int i = 0; i < _class_count; i++) { 960 // Create HandleMark so that any handles created while loading new class 961 // versions are deleted. Constant pools are deallocated while merging 962 // constant pools 963 HandleMark hm(THREAD); 964 965 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass); 966 // classes for primitives cannot be redefined 967 if (!is_modifiable_class(mirror)) { 968 return JVMTI_ERROR_UNMODIFIABLE_CLASS; 969 } 970 Klass* the_class_oop = java_lang_Class::as_Klass(mirror); 971 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop); 972 Symbol* the_class_sym = the_class->name(); 973 974 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 975 RC_TRACE_WITH_THREAD(0x00000001, THREAD, 976 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)", 977 the_class->external_name(), _class_load_kind, 978 os::available_memory() >> 10)); 979 980 ClassFileStream st((u1*) _class_defs[i].class_bytes, 981 _class_defs[i].class_byte_count, (char *)"__VM_RedefineClasses__"); 982 983 // Parse the stream. 984 Handle the_class_loader(THREAD, the_class->class_loader()); 985 Handle protection_domain(THREAD, the_class->protection_domain()); 986 // Set redefined class handle in JvmtiThreadState class. 987 // This redefined class is sent to agent event handler for class file 988 // load hook event. 989 state->set_class_being_redefined(&the_class, _class_load_kind); 990 991 Klass* k = SystemDictionary::parse_stream(the_class_sym, 992 the_class_loader, 993 protection_domain, 994 &st, 995 THREAD); 996 // Clear class_being_redefined just to be sure. 997 state->clear_class_being_redefined(); 998 999 // TODO: if this is retransform, and nothing changed we can skip it 1000 1001 instanceKlassHandle scratch_class (THREAD, k); 1002 1003 // Need to clean up allocated InstanceKlass if there's an error so assign 1004 // the result here. Caller deallocates all the scratch classes in case of 1005 // an error. 1006 _scratch_classes[i] = k; 1007 1008 if (HAS_PENDING_EXCEPTION) { 1009 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1010 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1011 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("parse_stream exception: '%s'", 1012 ex_name->as_C_string())); 1013 CLEAR_PENDING_EXCEPTION; 1014 1015 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) { 1016 return JVMTI_ERROR_UNSUPPORTED_VERSION; 1017 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) { 1018 return JVMTI_ERROR_INVALID_CLASS_FORMAT; 1019 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) { 1020 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION; 1021 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) { 1022 // The message will be "XXX (wrong name: YYY)" 1023 return JVMTI_ERROR_NAMES_DONT_MATCH; 1024 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1025 return JVMTI_ERROR_OUT_OF_MEMORY; 1026 } else { // Just in case more exceptions can be thrown.. 1027 return JVMTI_ERROR_FAILS_VERIFICATION; 1028 } 1029 } 1030 1031 // Ensure class is linked before redefine 1032 if (!the_class->is_linked()) { 1033 the_class->link_class(THREAD); 1034 if (HAS_PENDING_EXCEPTION) { 1035 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1036 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1037 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("link_class exception: '%s'", 1038 ex_name->as_C_string())); 1039 CLEAR_PENDING_EXCEPTION; 1040 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1041 return JVMTI_ERROR_OUT_OF_MEMORY; 1042 } else { 1043 return JVMTI_ERROR_INTERNAL; 1044 } 1045 } 1046 } 1047 1048 // Do the validity checks in compare_and_normalize_class_versions() 1049 // before verifying the byte codes. By doing these checks first, we 1050 // limit the number of functions that require redirection from 1051 // the_class to scratch_class. In particular, we don't have to 1052 // modify JNI GetSuperclass() and thus won't change its performance. 1053 jvmtiError res = compare_and_normalize_class_versions(the_class, 1054 scratch_class); 1055 if (res != JVMTI_ERROR_NONE) { 1056 return res; 1057 } 1058 1059 // verify what the caller passed us 1060 { 1061 // The bug 6214132 caused the verification to fail. 1062 // Information about the_class and scratch_class is temporarily 1063 // recorded into jvmtiThreadState. This data is used to redirect 1064 // the_class to scratch_class in the JVM_* functions called by the 1065 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed 1066 // description. 1067 RedefineVerifyMark rvm(&the_class, &scratch_class, state); 1068 Verifier::verify( 1069 scratch_class, Verifier::ThrowException, true, THREAD); 1070 } 1071 1072 if (HAS_PENDING_EXCEPTION) { 1073 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1074 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1075 RC_TRACE_WITH_THREAD(0x00000002, THREAD, 1076 ("verify_byte_codes exception: '%s'", ex_name->as_C_string())); 1077 CLEAR_PENDING_EXCEPTION; 1078 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1079 return JVMTI_ERROR_OUT_OF_MEMORY; 1080 } else { 1081 // tell the caller the bytecodes are bad 1082 return JVMTI_ERROR_FAILS_VERIFICATION; 1083 } 1084 } 1085 1086 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD); 1087 if (HAS_PENDING_EXCEPTION) { 1088 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1089 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1090 RC_TRACE_WITH_THREAD(0x00000002, THREAD, 1091 ("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string())); 1092 CLEAR_PENDING_EXCEPTION; 1093 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1094 return JVMTI_ERROR_OUT_OF_MEMORY; 1095 } else { 1096 return JVMTI_ERROR_INTERNAL; 1097 } 1098 } 1099 1100 if (VerifyMergedCPBytecodes) { 1101 // verify what we have done during constant pool merging 1102 { 1103 RedefineVerifyMark rvm(&the_class, &scratch_class, state); 1104 Verifier::verify(scratch_class, Verifier::ThrowException, true, THREAD); 1105 } 1106 1107 if (HAS_PENDING_EXCEPTION) { 1108 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1109 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1110 RC_TRACE_WITH_THREAD(0x00000002, THREAD, 1111 ("verify_byte_codes post merge-CP exception: '%s'", 1112 ex_name->as_C_string())); 1113 CLEAR_PENDING_EXCEPTION; 1114 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1115 return JVMTI_ERROR_OUT_OF_MEMORY; 1116 } else { 1117 // tell the caller that constant pool merging screwed up 1118 return JVMTI_ERROR_INTERNAL; 1119 } 1120 } 1121 } 1122 1123 Rewriter::rewrite(scratch_class, THREAD); 1124 if (!HAS_PENDING_EXCEPTION) { 1125 scratch_class->link_methods(THREAD); 1126 } 1127 if (HAS_PENDING_EXCEPTION) { 1128 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1129 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1130 RC_TRACE_WITH_THREAD(0x00000002, THREAD, 1131 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string())); 1132 CLEAR_PENDING_EXCEPTION; 1133 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1134 return JVMTI_ERROR_OUT_OF_MEMORY; 1135 } else { 1136 return JVMTI_ERROR_INTERNAL; 1137 } 1138 } 1139 1140 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1141 RC_TRACE_WITH_THREAD(0x00000001, THREAD, 1142 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)", 1143 the_class->external_name(), os::available_memory() >> 10)); 1144 } 1145 1146 return JVMTI_ERROR_NONE; 1147 } 1148 1149 1150 // Map old_index to new_index as needed. scratch_cp is only needed 1151 // for RC_TRACE() calls. 1152 void VM_RedefineClasses::map_index(constantPoolHandle scratch_cp, 1153 int old_index, int new_index) { 1154 if (find_new_index(old_index) != 0) { 1155 // old_index is already mapped 1156 return; 1157 } 1158 1159 if (old_index == new_index) { 1160 // no mapping is needed 1161 return; 1162 } 1163 1164 _index_map_p->at_put(old_index, new_index); 1165 _index_map_count++; 1166 1167 RC_TRACE(0x00040000, ("mapped tag %d at index %d to %d", 1168 scratch_cp->tag_at(old_index).value(), old_index, new_index)); 1169 } // end map_index() 1170 1171 1172 // Map old_index to new_index as needed. 1173 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) { 1174 if (find_new_operand_index(old_index) != -1) { 1175 // old_index is already mapped 1176 return; 1177 } 1178 1179 if (old_index == new_index) { 1180 // no mapping is needed 1181 return; 1182 } 1183 1184 _operands_index_map_p->at_put(old_index, new_index); 1185 _operands_index_map_count++; 1186 1187 RC_TRACE(0x00040000, ("mapped bootstrap specifier at index %d to %d", old_index, new_index)); 1188 } // end map_index() 1189 1190 1191 // Merge old_cp and scratch_cp and return the results of the merge via 1192 // merge_cp_p. The number of entries in *merge_cp_p is returned via 1193 // merge_cp_length_p. The entries in old_cp occupy the same locations 1194 // in *merge_cp_p. Also creates a map of indices from entries in 1195 // scratch_cp to the corresponding entry in *merge_cp_p. Index map 1196 // entries are only created for entries in scratch_cp that occupy a 1197 // different location in *merged_cp_p. 1198 bool VM_RedefineClasses::merge_constant_pools(constantPoolHandle old_cp, 1199 constantPoolHandle scratch_cp, constantPoolHandle *merge_cp_p, 1200 int *merge_cp_length_p, TRAPS) { 1201 1202 if (merge_cp_p == NULL) { 1203 assert(false, "caller must provide scratch constantPool"); 1204 return false; // robustness 1205 } 1206 if (merge_cp_length_p == NULL) { 1207 assert(false, "caller must provide scratch CP length"); 1208 return false; // robustness 1209 } 1210 // Worst case we need old_cp->length() + scratch_cp()->length(), 1211 // but the caller might be smart so make sure we have at least 1212 // the minimum. 1213 if ((*merge_cp_p)->length() < old_cp->length()) { 1214 assert(false, "merge area too small"); 1215 return false; // robustness 1216 } 1217 1218 RC_TRACE_WITH_THREAD(0x00010000, THREAD, 1219 ("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(), 1220 scratch_cp->length())); 1221 1222 { 1223 // Pass 0: 1224 // The old_cp is copied to *merge_cp_p; this means that any code 1225 // using old_cp does not have to change. This work looks like a 1226 // perfect fit for ConstantPool*::copy_cp_to(), but we need to 1227 // handle one special case: 1228 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass 1229 // This will make verification happy. 1230 1231 int old_i; // index into old_cp 1232 1233 // index zero (0) is not used in constantPools 1234 for (old_i = 1; old_i < old_cp->length(); old_i++) { 1235 // leave debugging crumb 1236 jbyte old_tag = old_cp->tag_at(old_i).value(); 1237 switch (old_tag) { 1238 case JVM_CONSTANT_Class: 1239 case JVM_CONSTANT_UnresolvedClass: 1240 // revert the copy to JVM_CONSTANT_UnresolvedClass 1241 // May be resolving while calling this so do the same for 1242 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition) 1243 (*merge_cp_p)->unresolved_klass_at_put(old_i, 1244 old_cp->klass_name_at(old_i)); 1245 break; 1246 1247 case JVM_CONSTANT_Double: 1248 case JVM_CONSTANT_Long: 1249 // just copy the entry to *merge_cp_p, but double and long take 1250 // two constant pool entries 1251 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0); 1252 old_i++; 1253 break; 1254 1255 default: 1256 // just copy the entry to *merge_cp_p 1257 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0); 1258 break; 1259 } 1260 } // end for each old_cp entry 1261 1262 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_0); 1263 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_0); 1264 1265 // We don't need to sanity check that *merge_cp_length_p is within 1266 // *merge_cp_p bounds since we have the minimum on-entry check above. 1267 (*merge_cp_length_p) = old_i; 1268 } 1269 1270 // merge_cp_len should be the same as old_cp->length() at this point 1271 // so this trace message is really a "warm-and-breathing" message. 1272 RC_TRACE_WITH_THREAD(0x00020000, THREAD, 1273 ("after pass 0: merge_cp_len=%d", *merge_cp_length_p)); 1274 1275 int scratch_i; // index into scratch_cp 1276 { 1277 // Pass 1a: 1278 // Compare scratch_cp entries to the old_cp entries that we have 1279 // already copied to *merge_cp_p. In this pass, we are eliminating 1280 // exact duplicates (matching entry at same index) so we only 1281 // compare entries in the common indice range. 1282 int increment = 1; 1283 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length()); 1284 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) { 1285 switch (scratch_cp->tag_at(scratch_i).value()) { 1286 case JVM_CONSTANT_Double: 1287 case JVM_CONSTANT_Long: 1288 // double and long take two constant pool entries 1289 increment = 2; 1290 break; 1291 1292 default: 1293 increment = 1; 1294 break; 1295 } 1296 1297 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p, 1298 scratch_i, CHECK_0); 1299 if (match) { 1300 // found a match at the same index so nothing more to do 1301 continue; 1302 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i, 1303 *merge_cp_p, scratch_i)) { 1304 // The mismatch in compare_entry_to() above is because of a 1305 // resolved versus unresolved class entry at the same index 1306 // with the same string value. Since Pass 0 reverted any 1307 // class entries to unresolved class entries in *merge_cp_p, 1308 // we go with the unresolved class entry. 1309 continue; 1310 } 1311 1312 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, 1313 CHECK_0); 1314 if (found_i != 0) { 1315 guarantee(found_i != scratch_i, 1316 "compare_entry_to() and find_matching_entry() do not agree"); 1317 1318 // Found a matching entry somewhere else in *merge_cp_p so 1319 // just need a mapping entry. 1320 map_index(scratch_cp, scratch_i, found_i); 1321 continue; 1322 } 1323 1324 // The find_matching_entry() call above could fail to find a match 1325 // due to a resolved versus unresolved class or string entry situation 1326 // like we solved above with the is_unresolved_*_mismatch() calls. 1327 // However, we would have to call is_unresolved_*_mismatch() over 1328 // all of *merge_cp_p (potentially) and that doesn't seem to be 1329 // worth the time. 1330 1331 // No match found so we have to append this entry and any unique 1332 // referenced entries to *merge_cp_p. 1333 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p, 1334 CHECK_0); 1335 } 1336 } 1337 1338 RC_TRACE_WITH_THREAD(0x00020000, THREAD, 1339 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", 1340 *merge_cp_length_p, scratch_i, _index_map_count)); 1341 1342 if (scratch_i < scratch_cp->length()) { 1343 // Pass 1b: 1344 // old_cp is smaller than scratch_cp so there are entries in 1345 // scratch_cp that we have not yet processed. We take care of 1346 // those now. 1347 int increment = 1; 1348 for (; scratch_i < scratch_cp->length(); scratch_i += increment) { 1349 switch (scratch_cp->tag_at(scratch_i).value()) { 1350 case JVM_CONSTANT_Double: 1351 case JVM_CONSTANT_Long: 1352 // double and long take two constant pool entries 1353 increment = 2; 1354 break; 1355 1356 default: 1357 increment = 1; 1358 break; 1359 } 1360 1361 int found_i = 1362 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0); 1363 if (found_i != 0) { 1364 // Found a matching entry somewhere else in *merge_cp_p so 1365 // just need a mapping entry. 1366 map_index(scratch_cp, scratch_i, found_i); 1367 continue; 1368 } 1369 1370 // No match found so we have to append this entry and any unique 1371 // referenced entries to *merge_cp_p. 1372 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p, 1373 CHECK_0); 1374 } 1375 1376 RC_TRACE_WITH_THREAD(0x00020000, THREAD, 1377 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", 1378 *merge_cp_length_p, scratch_i, _index_map_count)); 1379 } 1380 finalize_operands_merge(*merge_cp_p, THREAD); 1381 1382 return true; 1383 } // end merge_constant_pools() 1384 1385 1386 // Scoped object to clean up the constant pool(s) created for merging 1387 class MergeCPCleaner { 1388 ClassLoaderData* _loader_data; 1389 ConstantPool* _cp; 1390 ConstantPool* _scratch_cp; 1391 public: 1392 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) : 1393 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {} 1394 ~MergeCPCleaner() { 1395 _loader_data->add_to_deallocate_list(_cp); 1396 if (_scratch_cp != NULL) { 1397 _loader_data->add_to_deallocate_list(_scratch_cp); 1398 } 1399 } 1400 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; } 1401 }; 1402 1403 // Merge constant pools between the_class and scratch_class and 1404 // potentially rewrite bytecodes in scratch_class to use the merged 1405 // constant pool. 1406 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite( 1407 instanceKlassHandle the_class, instanceKlassHandle scratch_class, 1408 TRAPS) { 1409 // worst case merged constant pool length is old and new combined 1410 int merge_cp_length = the_class->constants()->length() 1411 + scratch_class->constants()->length(); 1412 1413 // Constant pools are not easily reused so we allocate a new one 1414 // each time. 1415 // merge_cp is created unsafe for concurrent GC processing. It 1416 // should be marked safe before discarding it. Even though 1417 // garbage, if it crosses a card boundary, it may be scanned 1418 // in order to find the start of the first complete object on the card. 1419 ClassLoaderData* loader_data = the_class->class_loader_data(); 1420 ConstantPool* merge_cp_oop = 1421 ConstantPool::allocate(loader_data, 1422 merge_cp_length, 1423 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1424 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop); 1425 1426 HandleMark hm(THREAD); // make sure handles are cleared before 1427 // MergeCPCleaner clears out merge_cp_oop 1428 constantPoolHandle merge_cp(THREAD, merge_cp_oop); 1429 1430 // Get constants() from the old class because it could have been rewritten 1431 // while we were at a safepoint allocating a new constant pool. 1432 constantPoolHandle old_cp(THREAD, the_class->constants()); 1433 constantPoolHandle scratch_cp(THREAD, scratch_class->constants()); 1434 1435 // If the length changed, the class was redefined out from under us. Return 1436 // an error. 1437 if (merge_cp_length != the_class->constants()->length() 1438 + scratch_class->constants()->length()) { 1439 return JVMTI_ERROR_INTERNAL; 1440 } 1441 1442 // Update the version number of the constant pool 1443 merge_cp->increment_and_save_version(old_cp->version()); 1444 1445 ResourceMark rm(THREAD); 1446 _index_map_count = 0; 1447 _index_map_p = new intArray(scratch_cp->length(), -1); 1448 1449 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands()); 1450 _operands_index_map_count = 0; 1451 _operands_index_map_p = new intArray( 1452 ConstantPool::operand_array_length(scratch_cp->operands()), -1); 1453 1454 // reference to the cp holder is needed for copy_operands() 1455 merge_cp->set_pool_holder(scratch_class()); 1456 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp, 1457 &merge_cp_length, THREAD); 1458 merge_cp->set_pool_holder(NULL); 1459 1460 if (!result) { 1461 // The merge can fail due to memory allocation failure or due 1462 // to robustness checks. 1463 return JVMTI_ERROR_INTERNAL; 1464 } 1465 1466 RC_TRACE_WITH_THREAD(0x00010000, THREAD, 1467 ("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count)); 1468 1469 if (_index_map_count == 0) { 1470 // there is nothing to map between the new and merged constant pools 1471 1472 if (old_cp->length() == scratch_cp->length()) { 1473 // The old and new constant pools are the same length and the 1474 // index map is empty. This means that the three constant pools 1475 // are equivalent (but not the same). Unfortunately, the new 1476 // constant pool has not gone through link resolution nor have 1477 // the new class bytecodes gone through constant pool cache 1478 // rewriting so we can't use the old constant pool with the new 1479 // class. 1480 1481 // toss the merged constant pool at return 1482 } else if (old_cp->length() < scratch_cp->length()) { 1483 // The old constant pool has fewer entries than the new constant 1484 // pool and the index map is empty. This means the new constant 1485 // pool is a superset of the old constant pool. However, the old 1486 // class bytecodes have already gone through constant pool cache 1487 // rewriting so we can't use the new constant pool with the old 1488 // class. 1489 1490 // toss the merged constant pool at return 1491 } else { 1492 // The old constant pool has more entries than the new constant 1493 // pool and the index map is empty. This means that both the old 1494 // and merged constant pools are supersets of the new constant 1495 // pool. 1496 1497 // Replace the new constant pool with a shrunken copy of the 1498 // merged constant pool 1499 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, 1500 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1501 // The new constant pool replaces scratch_cp so have cleaner clean it up. 1502 // It can't be cleaned up while there are handles to it. 1503 cp_cleaner.add_scratch_cp(scratch_cp()); 1504 } 1505 } else { 1506 if (RC_TRACE_ENABLED(0x00040000)) { 1507 // don't want to loop unless we are tracing 1508 int count = 0; 1509 for (int i = 1; i < _index_map_p->length(); i++) { 1510 int value = _index_map_p->at(i); 1511 1512 if (value != -1) { 1513 RC_TRACE_WITH_THREAD(0x00040000, THREAD, 1514 ("index_map[%d]: old=%d new=%d", count, i, value)); 1515 count++; 1516 } 1517 } 1518 } 1519 1520 // We have entries mapped between the new and merged constant pools 1521 // so we have to rewrite some constant pool references. 1522 if (!rewrite_cp_refs(scratch_class, THREAD)) { 1523 return JVMTI_ERROR_INTERNAL; 1524 } 1525 1526 // Replace the new constant pool with a shrunken copy of the 1527 // merged constant pool so now the rewritten bytecodes have 1528 // valid references; the previous new constant pool will get 1529 // GCed. 1530 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, 1531 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1532 // The new constant pool replaces scratch_cp so have cleaner clean it up. 1533 // It can't be cleaned up while there are handles to it. 1534 cp_cleaner.add_scratch_cp(scratch_cp()); 1535 } 1536 1537 return JVMTI_ERROR_NONE; 1538 } // end merge_cp_and_rewrite() 1539 1540 1541 // Rewrite constant pool references in klass scratch_class. 1542 bool VM_RedefineClasses::rewrite_cp_refs(instanceKlassHandle scratch_class, 1543 TRAPS) { 1544 1545 // rewrite constant pool references in the methods: 1546 if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) { 1547 // propagate failure back to caller 1548 return false; 1549 } 1550 1551 // rewrite constant pool references in the class_annotations: 1552 if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) { 1553 // propagate failure back to caller 1554 return false; 1555 } 1556 1557 // rewrite constant pool references in the fields_annotations: 1558 if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) { 1559 // propagate failure back to caller 1560 return false; 1561 } 1562 1563 // rewrite constant pool references in the methods_annotations: 1564 if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) { 1565 // propagate failure back to caller 1566 return false; 1567 } 1568 1569 // rewrite constant pool references in the methods_parameter_annotations: 1570 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class, 1571 THREAD)) { 1572 // propagate failure back to caller 1573 return false; 1574 } 1575 1576 // rewrite constant pool references in the methods_default_annotations: 1577 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class, 1578 THREAD)) { 1579 // propagate failure back to caller 1580 return false; 1581 } 1582 1583 // rewrite constant pool references in the class_type_annotations: 1584 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class, THREAD)) { 1585 // propagate failure back to caller 1586 return false; 1587 } 1588 1589 // rewrite constant pool references in the fields_type_annotations: 1590 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class, THREAD)) { 1591 // propagate failure back to caller 1592 return false; 1593 } 1594 1595 // rewrite constant pool references in the methods_type_annotations: 1596 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class, THREAD)) { 1597 // propagate failure back to caller 1598 return false; 1599 } 1600 1601 // There can be type annotations in the Code part of a method_info attribute. 1602 // These annotations are not accessible, even by reflection. 1603 // Currently they are not even parsed by the ClassFileParser. 1604 // If runtime access is added they will also need to be rewritten. 1605 1606 // rewrite source file name index: 1607 u2 source_file_name_idx = scratch_class->source_file_name_index(); 1608 if (source_file_name_idx != 0) { 1609 u2 new_source_file_name_idx = find_new_index(source_file_name_idx); 1610 if (new_source_file_name_idx != 0) { 1611 scratch_class->set_source_file_name_index(new_source_file_name_idx); 1612 } 1613 } 1614 1615 // rewrite class generic signature index: 1616 u2 generic_signature_index = scratch_class->generic_signature_index(); 1617 if (generic_signature_index != 0) { 1618 u2 new_generic_signature_index = find_new_index(generic_signature_index); 1619 if (new_generic_signature_index != 0) { 1620 scratch_class->set_generic_signature_index(new_generic_signature_index); 1621 } 1622 } 1623 1624 return true; 1625 } // end rewrite_cp_refs() 1626 1627 // Rewrite constant pool references in the methods. 1628 bool VM_RedefineClasses::rewrite_cp_refs_in_methods( 1629 instanceKlassHandle scratch_class, TRAPS) { 1630 1631 Array<Method*>* methods = scratch_class->methods(); 1632 1633 if (methods == NULL || methods->length() == 0) { 1634 // no methods so nothing to do 1635 return true; 1636 } 1637 1638 // rewrite constant pool references in the methods: 1639 for (int i = methods->length() - 1; i >= 0; i--) { 1640 methodHandle method(THREAD, methods->at(i)); 1641 methodHandle new_method; 1642 rewrite_cp_refs_in_method(method, &new_method, THREAD); 1643 if (!new_method.is_null()) { 1644 // the method has been replaced so save the new method version 1645 // even in the case of an exception. original method is on the 1646 // deallocation list. 1647 methods->at_put(i, new_method()); 1648 } 1649 if (HAS_PENDING_EXCEPTION) { 1650 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1651 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1652 RC_TRACE_WITH_THREAD(0x00000002, THREAD, 1653 ("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string())); 1654 // Need to clear pending exception here as the super caller sets 1655 // the JVMTI_ERROR_INTERNAL if the returned value is false. 1656 CLEAR_PENDING_EXCEPTION; 1657 return false; 1658 } 1659 } 1660 1661 return true; 1662 } 1663 1664 1665 // Rewrite constant pool references in the specific method. This code 1666 // was adapted from Rewriter::rewrite_method(). 1667 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method, 1668 methodHandle *new_method_p, TRAPS) { 1669 1670 *new_method_p = methodHandle(); // default is no new method 1671 1672 // We cache a pointer to the bytecodes here in code_base. If GC 1673 // moves the Method*, then the bytecodes will also move which 1674 // will likely cause a crash. We create a No_Safepoint_Verifier 1675 // object to detect whether we pass a possible safepoint in this 1676 // code block. 1677 No_Safepoint_Verifier nsv; 1678 1679 // Bytecodes and their length 1680 address code_base = method->code_base(); 1681 int code_length = method->code_size(); 1682 1683 int bc_length; 1684 for (int bci = 0; bci < code_length; bci += bc_length) { 1685 address bcp = code_base + bci; 1686 Bytecodes::Code c = (Bytecodes::Code)(*bcp); 1687 1688 bc_length = Bytecodes::length_for(c); 1689 if (bc_length == 0) { 1690 // More complicated bytecodes report a length of zero so 1691 // we have to try again a slightly different way. 1692 bc_length = Bytecodes::length_at(method(), bcp); 1693 } 1694 1695 assert(bc_length != 0, "impossible bytecode length"); 1696 1697 switch (c) { 1698 case Bytecodes::_ldc: 1699 { 1700 int cp_index = *(bcp + 1); 1701 int new_index = find_new_index(cp_index); 1702 1703 if (StressLdcRewrite && new_index == 0) { 1704 // If we are stressing ldc -> ldc_w rewriting, then we 1705 // always need a new_index value. 1706 new_index = cp_index; 1707 } 1708 if (new_index != 0) { 1709 // the original index is mapped so we have more work to do 1710 if (!StressLdcRewrite && new_index <= max_jubyte) { 1711 // The new value can still use ldc instead of ldc_w 1712 // unless we are trying to stress ldc -> ldc_w rewriting 1713 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 1714 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), 1715 p2i(bcp), cp_index, new_index)); 1716 *(bcp + 1) = new_index; 1717 } else { 1718 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 1719 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d", 1720 Bytecodes::name(c), p2i(bcp), cp_index, new_index)); 1721 // the new value needs ldc_w instead of ldc 1722 u_char inst_buffer[4]; // max instruction size is 4 bytes 1723 bcp = (address)inst_buffer; 1724 // construct new instruction sequence 1725 *bcp = Bytecodes::_ldc_w; 1726 bcp++; 1727 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w. 1728 // See comment below for difference between put_Java_u2() 1729 // and put_native_u2(). 1730 Bytes::put_Java_u2(bcp, new_index); 1731 1732 Relocator rc(method, NULL /* no RelocatorListener needed */); 1733 methodHandle m; 1734 { 1735 Pause_No_Safepoint_Verifier pnsv(&nsv); 1736 1737 // ldc is 2 bytes and ldc_w is 3 bytes 1738 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK); 1739 } 1740 1741 // return the new method so that the caller can update 1742 // the containing class 1743 *new_method_p = method = m; 1744 // switch our bytecode processing loop from the old method 1745 // to the new method 1746 code_base = method->code_base(); 1747 code_length = method->code_size(); 1748 bcp = code_base + bci; 1749 c = (Bytecodes::Code)(*bcp); 1750 bc_length = Bytecodes::length_for(c); 1751 assert(bc_length != 0, "sanity check"); 1752 } // end we need ldc_w instead of ldc 1753 } // end if there is a mapped index 1754 } break; 1755 1756 // these bytecodes have a two-byte constant pool index 1757 case Bytecodes::_anewarray : // fall through 1758 case Bytecodes::_checkcast : // fall through 1759 case Bytecodes::_getfield : // fall through 1760 case Bytecodes::_getstatic : // fall through 1761 case Bytecodes::_instanceof : // fall through 1762 case Bytecodes::_invokedynamic : // fall through 1763 case Bytecodes::_invokeinterface: // fall through 1764 case Bytecodes::_invokespecial : // fall through 1765 case Bytecodes::_invokestatic : // fall through 1766 case Bytecodes::_invokevirtual : // fall through 1767 case Bytecodes::_ldc_w : // fall through 1768 case Bytecodes::_ldc2_w : // fall through 1769 case Bytecodes::_multianewarray : // fall through 1770 case Bytecodes::_new : // fall through 1771 case Bytecodes::_putfield : // fall through 1772 case Bytecodes::_putstatic : 1773 { 1774 address p = bcp + 1; 1775 int cp_index = Bytes::get_Java_u2(p); 1776 int new_index = find_new_index(cp_index); 1777 if (new_index != 0) { 1778 // the original index is mapped so update w/ new value 1779 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 1780 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), 1781 p2i(bcp), cp_index, new_index)); 1782 // Rewriter::rewrite_method() uses put_native_u2() in this 1783 // situation because it is reusing the constant pool index 1784 // location for a native index into the ConstantPoolCache. 1785 // Since we are updating the constant pool index prior to 1786 // verification and ConstantPoolCache initialization, we 1787 // need to keep the new index in Java byte order. 1788 Bytes::put_Java_u2(p, new_index); 1789 } 1790 } break; 1791 } 1792 } // end for each bytecode 1793 1794 // We also need to rewrite the parameter name indexes, if there is 1795 // method parameter data present 1796 if(method->has_method_parameters()) { 1797 const int len = method->method_parameters_length(); 1798 MethodParametersElement* elem = method->method_parameters_start(); 1799 1800 for (int i = 0; i < len; i++) { 1801 const u2 cp_index = elem[i].name_cp_index; 1802 const u2 new_cp_index = find_new_index(cp_index); 1803 if (new_cp_index != 0) { 1804 elem[i].name_cp_index = new_cp_index; 1805 } 1806 } 1807 } 1808 } // end rewrite_cp_refs_in_method() 1809 1810 1811 // Rewrite constant pool references in the class_annotations field. 1812 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations( 1813 instanceKlassHandle scratch_class, TRAPS) { 1814 1815 AnnotationArray* class_annotations = scratch_class->class_annotations(); 1816 if (class_annotations == NULL || class_annotations->length() == 0) { 1817 // no class_annotations so nothing to do 1818 return true; 1819 } 1820 1821 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1822 ("class_annotations length=%d", class_annotations->length())); 1823 1824 int byte_i = 0; // byte index into class_annotations 1825 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i, 1826 THREAD); 1827 } 1828 1829 1830 // Rewrite constant pool references in an annotations typeArray. This 1831 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute 1832 // that is described in section 4.8.15 of the 2nd-edition of the VM spec: 1833 // 1834 // annotations_typeArray { 1835 // u2 num_annotations; 1836 // annotation annotations[num_annotations]; 1837 // } 1838 // 1839 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray( 1840 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) { 1841 1842 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 1843 // not enough room for num_annotations field 1844 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1845 ("length() is too small for num_annotations field")); 1846 return false; 1847 } 1848 1849 u2 num_annotations = Bytes::get_Java_u2((address) 1850 annotations_typeArray->adr_at(byte_i_ref)); 1851 byte_i_ref += 2; 1852 1853 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1854 ("num_annotations=%d", num_annotations)); 1855 1856 int calc_num_annotations = 0; 1857 for (; calc_num_annotations < num_annotations; calc_num_annotations++) { 1858 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, 1859 byte_i_ref, THREAD)) { 1860 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1861 ("bad annotation_struct at %d", calc_num_annotations)); 1862 // propagate failure back to caller 1863 return false; 1864 } 1865 } 1866 assert(num_annotations == calc_num_annotations, "sanity check"); 1867 1868 return true; 1869 } // end rewrite_cp_refs_in_annotations_typeArray() 1870 1871 1872 // Rewrite constant pool references in the annotation struct portion of 1873 // an annotations_typeArray. This "structure" is from section 4.8.15 of 1874 // the 2nd-edition of the VM spec: 1875 // 1876 // struct annotation { 1877 // u2 type_index; 1878 // u2 num_element_value_pairs; 1879 // { 1880 // u2 element_name_index; 1881 // element_value value; 1882 // } element_value_pairs[num_element_value_pairs]; 1883 // } 1884 // 1885 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct( 1886 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) { 1887 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) { 1888 // not enough room for smallest annotation_struct 1889 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1890 ("length() is too small for annotation_struct")); 1891 return false; 1892 } 1893 1894 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray, 1895 byte_i_ref, "mapped old type_index=%d", THREAD); 1896 1897 u2 num_element_value_pairs = Bytes::get_Java_u2((address) 1898 annotations_typeArray->adr_at(byte_i_ref)); 1899 byte_i_ref += 2; 1900 1901 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1902 ("type_index=%d num_element_value_pairs=%d", type_index, 1903 num_element_value_pairs)); 1904 1905 int calc_num_element_value_pairs = 0; 1906 for (; calc_num_element_value_pairs < num_element_value_pairs; 1907 calc_num_element_value_pairs++) { 1908 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 1909 // not enough room for another element_name_index, let alone 1910 // the rest of another component 1911 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1912 ("length() is too small for element_name_index")); 1913 return false; 1914 } 1915 1916 u2 element_name_index = rewrite_cp_ref_in_annotation_data( 1917 annotations_typeArray, byte_i_ref, 1918 "mapped old element_name_index=%d", THREAD); 1919 1920 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1921 ("element_name_index=%d", element_name_index)); 1922 1923 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, 1924 byte_i_ref, THREAD)) { 1925 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1926 ("bad element_value at %d", calc_num_element_value_pairs)); 1927 // propagate failure back to caller 1928 return false; 1929 } 1930 } // end for each component 1931 assert(num_element_value_pairs == calc_num_element_value_pairs, 1932 "sanity check"); 1933 1934 return true; 1935 } // end rewrite_cp_refs_in_annotation_struct() 1936 1937 1938 // Rewrite a constant pool reference at the current position in 1939 // annotations_typeArray if needed. Returns the original constant 1940 // pool reference if a rewrite was not needed or the new constant 1941 // pool reference if a rewrite was needed. 1942 PRAGMA_DIAG_PUSH 1943 PRAGMA_FORMAT_NONLITERAL_IGNORED 1944 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data( 1945 AnnotationArray* annotations_typeArray, int &byte_i_ref, 1946 const char * trace_mesg, TRAPS) { 1947 1948 address cp_index_addr = (address) 1949 annotations_typeArray->adr_at(byte_i_ref); 1950 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr); 1951 u2 new_cp_index = find_new_index(old_cp_index); 1952 if (new_cp_index != 0) { 1953 RC_TRACE_WITH_THREAD(0x02000000, THREAD, (trace_mesg, old_cp_index)); 1954 Bytes::put_Java_u2(cp_index_addr, new_cp_index); 1955 old_cp_index = new_cp_index; 1956 } 1957 byte_i_ref += 2; 1958 return old_cp_index; 1959 } 1960 PRAGMA_DIAG_POP 1961 1962 1963 // Rewrite constant pool references in the element_value portion of an 1964 // annotations_typeArray. This "structure" is from section 4.8.15.1 of 1965 // the 2nd-edition of the VM spec: 1966 // 1967 // struct element_value { 1968 // u1 tag; 1969 // union { 1970 // u2 const_value_index; 1971 // { 1972 // u2 type_name_index; 1973 // u2 const_name_index; 1974 // } enum_const_value; 1975 // u2 class_info_index; 1976 // annotation annotation_value; 1977 // struct { 1978 // u2 num_values; 1979 // element_value values[num_values]; 1980 // } array_value; 1981 // } value; 1982 // } 1983 // 1984 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value( 1985 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) { 1986 1987 if ((byte_i_ref + 1) > annotations_typeArray->length()) { 1988 // not enough room for a tag let alone the rest of an element_value 1989 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1990 ("length() is too small for a tag")); 1991 return false; 1992 } 1993 1994 u1 tag = annotations_typeArray->at(byte_i_ref); 1995 byte_i_ref++; 1996 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("tag='%c'", tag)); 1997 1998 switch (tag) { 1999 // These BaseType tag values are from Table 4.2 in VM spec: 2000 case 'B': // byte 2001 case 'C': // char 2002 case 'D': // double 2003 case 'F': // float 2004 case 'I': // int 2005 case 'J': // long 2006 case 'S': // short 2007 case 'Z': // boolean 2008 2009 // The remaining tag values are from Table 4.8 in the 2nd-edition of 2010 // the VM spec: 2011 case 's': 2012 { 2013 // For the above tag values (including the BaseType values), 2014 // value.const_value_index is right union field. 2015 2016 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2017 // not enough room for a const_value_index 2018 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2019 ("length() is too small for a const_value_index")); 2020 return false; 2021 } 2022 2023 u2 const_value_index = rewrite_cp_ref_in_annotation_data( 2024 annotations_typeArray, byte_i_ref, 2025 "mapped old const_value_index=%d", THREAD); 2026 2027 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2028 ("const_value_index=%d", const_value_index)); 2029 } break; 2030 2031 case 'e': 2032 { 2033 // for the above tag value, value.enum_const_value is right union field 2034 2035 if ((byte_i_ref + 4) > annotations_typeArray->length()) { 2036 // not enough room for a enum_const_value 2037 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2038 ("length() is too small for a enum_const_value")); 2039 return false; 2040 } 2041 2042 u2 type_name_index = rewrite_cp_ref_in_annotation_data( 2043 annotations_typeArray, byte_i_ref, 2044 "mapped old type_name_index=%d", THREAD); 2045 2046 u2 const_name_index = rewrite_cp_ref_in_annotation_data( 2047 annotations_typeArray, byte_i_ref, 2048 "mapped old const_name_index=%d", THREAD); 2049 2050 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2051 ("type_name_index=%d const_name_index=%d", type_name_index, 2052 const_name_index)); 2053 } break; 2054 2055 case 'c': 2056 { 2057 // for the above tag value, value.class_info_index is right union field 2058 2059 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2060 // not enough room for a class_info_index 2061 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2062 ("length() is too small for a class_info_index")); 2063 return false; 2064 } 2065 2066 u2 class_info_index = rewrite_cp_ref_in_annotation_data( 2067 annotations_typeArray, byte_i_ref, 2068 "mapped old class_info_index=%d", THREAD); 2069 2070 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2071 ("class_info_index=%d", class_info_index)); 2072 } break; 2073 2074 case '@': 2075 // For the above tag value, value.attr_value is the right union 2076 // field. This is a nested annotation. 2077 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, 2078 byte_i_ref, THREAD)) { 2079 // propagate failure back to caller 2080 return false; 2081 } 2082 break; 2083 2084 case '[': 2085 { 2086 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2087 // not enough room for a num_values field 2088 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2089 ("length() is too small for a num_values field")); 2090 return false; 2091 } 2092 2093 // For the above tag value, value.array_value is the right union 2094 // field. This is an array of nested element_value. 2095 u2 num_values = Bytes::get_Java_u2((address) 2096 annotations_typeArray->adr_at(byte_i_ref)); 2097 byte_i_ref += 2; 2098 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("num_values=%d", num_values)); 2099 2100 int calc_num_values = 0; 2101 for (; calc_num_values < num_values; calc_num_values++) { 2102 if (!rewrite_cp_refs_in_element_value( 2103 annotations_typeArray, byte_i_ref, THREAD)) { 2104 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2105 ("bad nested element_value at %d", calc_num_values)); 2106 // propagate failure back to caller 2107 return false; 2108 } 2109 } 2110 assert(num_values == calc_num_values, "sanity check"); 2111 } break; 2112 2113 default: 2114 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("bad tag=0x%x", tag)); 2115 return false; 2116 } // end decode tag field 2117 2118 return true; 2119 } // end rewrite_cp_refs_in_element_value() 2120 2121 2122 // Rewrite constant pool references in a fields_annotations field. 2123 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations( 2124 instanceKlassHandle scratch_class, TRAPS) { 2125 2126 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations(); 2127 2128 if (fields_annotations == NULL || fields_annotations->length() == 0) { 2129 // no fields_annotations so nothing to do 2130 return true; 2131 } 2132 2133 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2134 ("fields_annotations length=%d", fields_annotations->length())); 2135 2136 for (int i = 0; i < fields_annotations->length(); i++) { 2137 AnnotationArray* field_annotations = fields_annotations->at(i); 2138 if (field_annotations == NULL || field_annotations->length() == 0) { 2139 // this field does not have any annotations so skip it 2140 continue; 2141 } 2142 2143 int byte_i = 0; // byte index into field_annotations 2144 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i, 2145 THREAD)) { 2146 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2147 ("bad field_annotations at %d", i)); 2148 // propagate failure back to caller 2149 return false; 2150 } 2151 } 2152 2153 return true; 2154 } // end rewrite_cp_refs_in_fields_annotations() 2155 2156 2157 // Rewrite constant pool references in a methods_annotations field. 2158 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations( 2159 instanceKlassHandle scratch_class, TRAPS) { 2160 2161 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2162 Method* m = scratch_class->methods()->at(i); 2163 AnnotationArray* method_annotations = m->constMethod()->method_annotations(); 2164 2165 if (method_annotations == NULL || method_annotations->length() == 0) { 2166 // this method does not have any annotations so skip it 2167 continue; 2168 } 2169 2170 int byte_i = 0; // byte index into method_annotations 2171 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i, 2172 THREAD)) { 2173 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2174 ("bad method_annotations at %d", i)); 2175 // propagate failure back to caller 2176 return false; 2177 } 2178 } 2179 2180 return true; 2181 } // end rewrite_cp_refs_in_methods_annotations() 2182 2183 2184 // Rewrite constant pool references in a methods_parameter_annotations 2185 // field. This "structure" is adapted from the 2186 // RuntimeVisibleParameterAnnotations_attribute described in section 2187 // 4.8.17 of the 2nd-edition of the VM spec: 2188 // 2189 // methods_parameter_annotations_typeArray { 2190 // u1 num_parameters; 2191 // { 2192 // u2 num_annotations; 2193 // annotation annotations[num_annotations]; 2194 // } parameter_annotations[num_parameters]; 2195 // } 2196 // 2197 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations( 2198 instanceKlassHandle scratch_class, TRAPS) { 2199 2200 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2201 Method* m = scratch_class->methods()->at(i); 2202 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations(); 2203 if (method_parameter_annotations == NULL 2204 || method_parameter_annotations->length() == 0) { 2205 // this method does not have any parameter annotations so skip it 2206 continue; 2207 } 2208 2209 if (method_parameter_annotations->length() < 1) { 2210 // not enough room for a num_parameters field 2211 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2212 ("length() is too small for a num_parameters field at %d", i)); 2213 return false; 2214 } 2215 2216 int byte_i = 0; // byte index into method_parameter_annotations 2217 2218 u1 num_parameters = method_parameter_annotations->at(byte_i); 2219 byte_i++; 2220 2221 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2222 ("num_parameters=%d", num_parameters)); 2223 2224 int calc_num_parameters = 0; 2225 for (; calc_num_parameters < num_parameters; calc_num_parameters++) { 2226 if (!rewrite_cp_refs_in_annotations_typeArray( 2227 method_parameter_annotations, byte_i, THREAD)) { 2228 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2229 ("bad method_parameter_annotations at %d", calc_num_parameters)); 2230 // propagate failure back to caller 2231 return false; 2232 } 2233 } 2234 assert(num_parameters == calc_num_parameters, "sanity check"); 2235 } 2236 2237 return true; 2238 } // end rewrite_cp_refs_in_methods_parameter_annotations() 2239 2240 2241 // Rewrite constant pool references in a methods_default_annotations 2242 // field. This "structure" is adapted from the AnnotationDefault_attribute 2243 // that is described in section 4.8.19 of the 2nd-edition of the VM spec: 2244 // 2245 // methods_default_annotations_typeArray { 2246 // element_value default_value; 2247 // } 2248 // 2249 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations( 2250 instanceKlassHandle scratch_class, TRAPS) { 2251 2252 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2253 Method* m = scratch_class->methods()->at(i); 2254 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations(); 2255 if (method_default_annotations == NULL 2256 || method_default_annotations->length() == 0) { 2257 // this method does not have any default annotations so skip it 2258 continue; 2259 } 2260 2261 int byte_i = 0; // byte index into method_default_annotations 2262 2263 if (!rewrite_cp_refs_in_element_value( 2264 method_default_annotations, byte_i, THREAD)) { 2265 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2266 ("bad default element_value at %d", i)); 2267 // propagate failure back to caller 2268 return false; 2269 } 2270 } 2271 2272 return true; 2273 } // end rewrite_cp_refs_in_methods_default_annotations() 2274 2275 2276 // Rewrite constant pool references in a class_type_annotations field. 2277 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations( 2278 instanceKlassHandle scratch_class, TRAPS) { 2279 2280 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations(); 2281 if (class_type_annotations == NULL || class_type_annotations->length() == 0) { 2282 // no class_type_annotations so nothing to do 2283 return true; 2284 } 2285 2286 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2287 ("class_type_annotations length=%d", class_type_annotations->length())); 2288 2289 int byte_i = 0; // byte index into class_type_annotations 2290 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations, 2291 byte_i, "ClassFile", THREAD); 2292 } // end rewrite_cp_refs_in_class_type_annotations() 2293 2294 2295 // Rewrite constant pool references in a fields_type_annotations field. 2296 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations( 2297 instanceKlassHandle scratch_class, TRAPS) { 2298 2299 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations(); 2300 if (fields_type_annotations == NULL || fields_type_annotations->length() == 0) { 2301 // no fields_type_annotations so nothing to do 2302 return true; 2303 } 2304 2305 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2306 ("fields_type_annotations length=%d", fields_type_annotations->length())); 2307 2308 for (int i = 0; i < fields_type_annotations->length(); i++) { 2309 AnnotationArray* field_type_annotations = fields_type_annotations->at(i); 2310 if (field_type_annotations == NULL || field_type_annotations->length() == 0) { 2311 // this field does not have any annotations so skip it 2312 continue; 2313 } 2314 2315 int byte_i = 0; // byte index into field_type_annotations 2316 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations, 2317 byte_i, "field_info", THREAD)) { 2318 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2319 ("bad field_type_annotations at %d", i)); 2320 // propagate failure back to caller 2321 return false; 2322 } 2323 } 2324 2325 return true; 2326 } // end rewrite_cp_refs_in_fields_type_annotations() 2327 2328 2329 // Rewrite constant pool references in a methods_type_annotations field. 2330 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations( 2331 instanceKlassHandle scratch_class, TRAPS) { 2332 2333 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2334 Method* m = scratch_class->methods()->at(i); 2335 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations(); 2336 2337 if (method_type_annotations == NULL || method_type_annotations->length() == 0) { 2338 // this method does not have any annotations so skip it 2339 continue; 2340 } 2341 2342 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2343 ("methods type_annotations length=%d", method_type_annotations->length())); 2344 2345 int byte_i = 0; // byte index into method_type_annotations 2346 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations, 2347 byte_i, "method_info", THREAD)) { 2348 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2349 ("bad method_type_annotations at %d", i)); 2350 // propagate failure back to caller 2351 return false; 2352 } 2353 } 2354 2355 return true; 2356 } // end rewrite_cp_refs_in_methods_type_annotations() 2357 2358 2359 // Rewrite constant pool references in a type_annotations 2360 // field. This "structure" is adapted from the 2361 // RuntimeVisibleTypeAnnotations_attribute described in 2362 // section 4.7.20 of the Java SE 8 Edition of the VM spec: 2363 // 2364 // type_annotations_typeArray { 2365 // u2 num_annotations; 2366 // type_annotation annotations[num_annotations]; 2367 // } 2368 // 2369 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray( 2370 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2371 const char * location_mesg, TRAPS) { 2372 2373 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2374 // not enough room for num_annotations field 2375 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2376 ("length() is too small for num_annotations field")); 2377 return false; 2378 } 2379 2380 u2 num_annotations = Bytes::get_Java_u2((address) 2381 type_annotations_typeArray->adr_at(byte_i_ref)); 2382 byte_i_ref += 2; 2383 2384 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2385 ("num_type_annotations=%d", num_annotations)); 2386 2387 int calc_num_annotations = 0; 2388 for (; calc_num_annotations < num_annotations; calc_num_annotations++) { 2389 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray, 2390 byte_i_ref, location_mesg, THREAD)) { 2391 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2392 ("bad type_annotation_struct at %d", calc_num_annotations)); 2393 // propagate failure back to caller 2394 return false; 2395 } 2396 } 2397 assert(num_annotations == calc_num_annotations, "sanity check"); 2398 2399 if (byte_i_ref != type_annotations_typeArray->length()) { 2400 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2401 ("read wrong amount of bytes at end of processing " 2402 "type_annotations_typeArray (%d of %d bytes were read)", 2403 byte_i_ref, type_annotations_typeArray->length())); 2404 return false; 2405 } 2406 2407 return true; 2408 } // end rewrite_cp_refs_in_type_annotations_typeArray() 2409 2410 2411 // Rewrite constant pool references in a type_annotation 2412 // field. This "structure" is adapted from the 2413 // RuntimeVisibleTypeAnnotations_attribute described in 2414 // section 4.7.20 of the Java SE 8 Edition of the VM spec: 2415 // 2416 // type_annotation { 2417 // u1 target_type; 2418 // union { 2419 // type_parameter_target; 2420 // supertype_target; 2421 // type_parameter_bound_target; 2422 // empty_target; 2423 // method_formal_parameter_target; 2424 // throws_target; 2425 // localvar_target; 2426 // catch_target; 2427 // offset_target; 2428 // type_argument_target; 2429 // } target_info; 2430 // type_path target_path; 2431 // annotation anno; 2432 // } 2433 // 2434 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct( 2435 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2436 const char * location_mesg, TRAPS) { 2437 2438 if (!skip_type_annotation_target(type_annotations_typeArray, 2439 byte_i_ref, location_mesg, THREAD)) { 2440 return false; 2441 } 2442 2443 if (!skip_type_annotation_type_path(type_annotations_typeArray, 2444 byte_i_ref, THREAD)) { 2445 return false; 2446 } 2447 2448 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray, 2449 byte_i_ref, THREAD)) { 2450 return false; 2451 } 2452 2453 return true; 2454 } // end rewrite_cp_refs_in_type_annotation_struct() 2455 2456 2457 // Read, verify and skip over the target_type and target_info part 2458 // so that rewriting can continue in the later parts of the struct. 2459 // 2460 // u1 target_type; 2461 // union { 2462 // type_parameter_target; 2463 // supertype_target; 2464 // type_parameter_bound_target; 2465 // empty_target; 2466 // method_formal_parameter_target; 2467 // throws_target; 2468 // localvar_target; 2469 // catch_target; 2470 // offset_target; 2471 // type_argument_target; 2472 // } target_info; 2473 // 2474 bool VM_RedefineClasses::skip_type_annotation_target( 2475 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2476 const char * location_mesg, TRAPS) { 2477 2478 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2479 // not enough room for a target_type let alone the rest of a type_annotation 2480 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2481 ("length() is too small for a target_type")); 2482 return false; 2483 } 2484 2485 u1 target_type = type_annotations_typeArray->at(byte_i_ref); 2486 byte_i_ref += 1; 2487 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("target_type=0x%.2x", target_type)); 2488 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("location=%s", location_mesg)); 2489 2490 // Skip over target_info 2491 switch (target_type) { 2492 case 0x00: 2493 // kind: type parameter declaration of generic class or interface 2494 // location: ClassFile 2495 case 0x01: 2496 // kind: type parameter declaration of generic method or constructor 2497 // location: method_info 2498 2499 { 2500 // struct: 2501 // type_parameter_target { 2502 // u1 type_parameter_index; 2503 // } 2504 // 2505 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2506 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2507 ("length() is too small for a type_parameter_target")); 2508 return false; 2509 } 2510 2511 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2512 byte_i_ref += 1; 2513 2514 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2515 ("type_parameter_target: type_parameter_index=%d", 2516 type_parameter_index)); 2517 } break; 2518 2519 case 0x10: 2520 // kind: type in extends clause of class or interface declaration 2521 // (including the direct superclass of an anonymous class declaration), 2522 // or in implements clause of interface declaration 2523 // location: ClassFile 2524 2525 { 2526 // struct: 2527 // supertype_target { 2528 // u2 supertype_index; 2529 // } 2530 // 2531 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2532 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2533 ("length() is too small for a supertype_target")); 2534 return false; 2535 } 2536 2537 u2 supertype_index = Bytes::get_Java_u2((address) 2538 type_annotations_typeArray->adr_at(byte_i_ref)); 2539 byte_i_ref += 2; 2540 2541 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2542 ("supertype_target: supertype_index=%d", supertype_index)); 2543 } break; 2544 2545 case 0x11: 2546 // kind: type in bound of type parameter declaration of generic class or interface 2547 // location: ClassFile 2548 case 0x12: 2549 // kind: type in bound of type parameter declaration of generic method or constructor 2550 // location: method_info 2551 2552 { 2553 // struct: 2554 // type_parameter_bound_target { 2555 // u1 type_parameter_index; 2556 // u1 bound_index; 2557 // } 2558 // 2559 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2560 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2561 ("length() is too small for a type_parameter_bound_target")); 2562 return false; 2563 } 2564 2565 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2566 byte_i_ref += 1; 2567 u1 bound_index = type_annotations_typeArray->at(byte_i_ref); 2568 byte_i_ref += 1; 2569 2570 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2571 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d", 2572 type_parameter_index, bound_index)); 2573 } break; 2574 2575 case 0x13: 2576 // kind: type in field declaration 2577 // location: field_info 2578 case 0x14: 2579 // kind: return type of method, or type of newly constructed object 2580 // location: method_info 2581 case 0x15: 2582 // kind: receiver type of method or constructor 2583 // location: method_info 2584 2585 { 2586 // struct: 2587 // empty_target { 2588 // } 2589 // 2590 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2591 ("empty_target")); 2592 } break; 2593 2594 case 0x16: 2595 // kind: type in formal parameter declaration of method, constructor, or lambda expression 2596 // location: method_info 2597 2598 { 2599 // struct: 2600 // formal_parameter_target { 2601 // u1 formal_parameter_index; 2602 // } 2603 // 2604 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2605 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2606 ("length() is too small for a formal_parameter_target")); 2607 return false; 2608 } 2609 2610 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2611 byte_i_ref += 1; 2612 2613 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2614 ("formal_parameter_target: formal_parameter_index=%d", 2615 formal_parameter_index)); 2616 } break; 2617 2618 case 0x17: 2619 // kind: type in throws clause of method or constructor 2620 // location: method_info 2621 2622 { 2623 // struct: 2624 // throws_target { 2625 // u2 throws_type_index 2626 // } 2627 // 2628 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2629 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2630 ("length() is too small for a throws_target")); 2631 return false; 2632 } 2633 2634 u2 throws_type_index = Bytes::get_Java_u2((address) 2635 type_annotations_typeArray->adr_at(byte_i_ref)); 2636 byte_i_ref += 2; 2637 2638 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2639 ("throws_target: throws_type_index=%d", throws_type_index)); 2640 } break; 2641 2642 case 0x40: 2643 // kind: type in local variable declaration 2644 // location: Code 2645 case 0x41: 2646 // kind: type in resource variable declaration 2647 // location: Code 2648 2649 { 2650 // struct: 2651 // localvar_target { 2652 // u2 table_length; 2653 // struct { 2654 // u2 start_pc; 2655 // u2 length; 2656 // u2 index; 2657 // } table[table_length]; 2658 // } 2659 // 2660 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2661 // not enough room for a table_length let alone the rest of a localvar_target 2662 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2663 ("length() is too small for a localvar_target table_length")); 2664 return false; 2665 } 2666 2667 u2 table_length = Bytes::get_Java_u2((address) 2668 type_annotations_typeArray->adr_at(byte_i_ref)); 2669 byte_i_ref += 2; 2670 2671 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2672 ("localvar_target: table_length=%d", table_length)); 2673 2674 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry 2675 int table_size = table_length * table_struct_size; 2676 2677 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) { 2678 // not enough room for a table 2679 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2680 ("length() is too small for a table array of length %d", table_length)); 2681 return false; 2682 } 2683 2684 // Skip over table 2685 byte_i_ref += table_size; 2686 } break; 2687 2688 case 0x42: 2689 // kind: type in exception parameter declaration 2690 // location: Code 2691 2692 { 2693 // struct: 2694 // catch_target { 2695 // u2 exception_table_index; 2696 // } 2697 // 2698 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2699 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2700 ("length() is too small for a catch_target")); 2701 return false; 2702 } 2703 2704 u2 exception_table_index = Bytes::get_Java_u2((address) 2705 type_annotations_typeArray->adr_at(byte_i_ref)); 2706 byte_i_ref += 2; 2707 2708 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2709 ("catch_target: exception_table_index=%d", exception_table_index)); 2710 } break; 2711 2712 case 0x43: 2713 // kind: type in instanceof expression 2714 // location: Code 2715 case 0x44: 2716 // kind: type in new expression 2717 // location: Code 2718 case 0x45: 2719 // kind: type in method reference expression using ::new 2720 // location: Code 2721 case 0x46: 2722 // kind: type in method reference expression using ::Identifier 2723 // location: Code 2724 2725 { 2726 // struct: 2727 // offset_target { 2728 // u2 offset; 2729 // } 2730 // 2731 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2732 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2733 ("length() is too small for a offset_target")); 2734 return false; 2735 } 2736 2737 u2 offset = Bytes::get_Java_u2((address) 2738 type_annotations_typeArray->adr_at(byte_i_ref)); 2739 byte_i_ref += 2; 2740 2741 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2742 ("offset_target: offset=%d", offset)); 2743 } break; 2744 2745 case 0x47: 2746 // kind: type in cast expression 2747 // location: Code 2748 case 0x48: 2749 // kind: type argument for generic constructor in new expression or 2750 // explicit constructor invocation statement 2751 // location: Code 2752 case 0x49: 2753 // kind: type argument for generic method in method invocation expression 2754 // location: Code 2755 case 0x4A: 2756 // kind: type argument for generic constructor in method reference expression using ::new 2757 // location: Code 2758 case 0x4B: 2759 // kind: type argument for generic method in method reference expression using ::Identifier 2760 // location: Code 2761 2762 { 2763 // struct: 2764 // type_argument_target { 2765 // u2 offset; 2766 // u1 type_argument_index; 2767 // } 2768 // 2769 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) { 2770 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2771 ("length() is too small for a type_argument_target")); 2772 return false; 2773 } 2774 2775 u2 offset = Bytes::get_Java_u2((address) 2776 type_annotations_typeArray->adr_at(byte_i_ref)); 2777 byte_i_ref += 2; 2778 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref); 2779 byte_i_ref += 1; 2780 2781 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2782 ("type_argument_target: offset=%d, type_argument_index=%d", 2783 offset, type_argument_index)); 2784 } break; 2785 2786 default: 2787 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2788 ("unknown target_type")); 2789 #ifdef ASSERT 2790 ShouldNotReachHere(); 2791 #endif 2792 return false; 2793 } 2794 2795 return true; 2796 } // end skip_type_annotation_target() 2797 2798 2799 // Read, verify and skip over the type_path part so that rewriting 2800 // can continue in the later parts of the struct. 2801 // 2802 // type_path { 2803 // u1 path_length; 2804 // { 2805 // u1 type_path_kind; 2806 // u1 type_argument_index; 2807 // } path[path_length]; 2808 // } 2809 // 2810 bool VM_RedefineClasses::skip_type_annotation_type_path( 2811 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, TRAPS) { 2812 2813 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2814 // not enough room for a path_length let alone the rest of the type_path 2815 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2816 ("length() is too small for a type_path")); 2817 return false; 2818 } 2819 2820 u1 path_length = type_annotations_typeArray->at(byte_i_ref); 2821 byte_i_ref += 1; 2822 2823 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2824 ("type_path: path_length=%d", path_length)); 2825 2826 int calc_path_length = 0; 2827 for (; calc_path_length < path_length; calc_path_length++) { 2828 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) { 2829 // not enough room for a path 2830 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2831 ("length() is too small for path entry %d of %d", 2832 calc_path_length, path_length)); 2833 return false; 2834 } 2835 2836 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref); 2837 byte_i_ref += 1; 2838 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref); 2839 byte_i_ref += 1; 2840 2841 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2842 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d", 2843 calc_path_length, type_path_kind, type_argument_index)); 2844 2845 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) { 2846 // not enough room for a path 2847 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2848 ("inconsistent type_path values")); 2849 return false; 2850 } 2851 } 2852 assert(path_length == calc_path_length, "sanity check"); 2853 2854 return true; 2855 } // end skip_type_annotation_type_path() 2856 2857 2858 // Rewrite constant pool references in the method's stackmap table. 2859 // These "structures" are adapted from the StackMapTable_attribute that 2860 // is described in section 4.8.4 of the 6.0 version of the VM spec 2861 // (dated 2005.10.26): 2862 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf 2863 // 2864 // stack_map { 2865 // u2 number_of_entries; 2866 // stack_map_frame entries[number_of_entries]; 2867 // } 2868 // 2869 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table( 2870 methodHandle method, TRAPS) { 2871 2872 if (!method->has_stackmap_table()) { 2873 return; 2874 } 2875 2876 AnnotationArray* stackmap_data = method->stackmap_data(); 2877 address stackmap_p = (address)stackmap_data->adr_at(0); 2878 address stackmap_end = stackmap_p + stackmap_data->length(); 2879 2880 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries"); 2881 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p); 2882 stackmap_p += 2; 2883 2884 RC_TRACE_WITH_THREAD(0x04000000, THREAD, 2885 ("number_of_entries=%u", number_of_entries)); 2886 2887 // walk through each stack_map_frame 2888 u2 calc_number_of_entries = 0; 2889 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) { 2890 // The stack_map_frame structure is a u1 frame_type followed by 2891 // 0 or more bytes of data: 2892 // 2893 // union stack_map_frame { 2894 // same_frame; 2895 // same_locals_1_stack_item_frame; 2896 // same_locals_1_stack_item_frame_extended; 2897 // chop_frame; 2898 // same_frame_extended; 2899 // append_frame; 2900 // full_frame; 2901 // } 2902 2903 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type"); 2904 u1 frame_type = *stackmap_p; 2905 stackmap_p++; 2906 2907 // same_frame { 2908 // u1 frame_type = SAME; /* 0-63 */ 2909 // } 2910 if (frame_type <= 63) { 2911 // nothing more to do for same_frame 2912 } 2913 2914 // same_locals_1_stack_item_frame { 2915 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */ 2916 // verification_type_info stack[1]; 2917 // } 2918 else if (frame_type >= 64 && frame_type <= 127) { 2919 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2920 calc_number_of_entries, frame_type, THREAD); 2921 } 2922 2923 // reserved for future use 2924 else if (frame_type >= 128 && frame_type <= 246) { 2925 // nothing more to do for reserved frame_types 2926 } 2927 2928 // same_locals_1_stack_item_frame_extended { 2929 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */ 2930 // u2 offset_delta; 2931 // verification_type_info stack[1]; 2932 // } 2933 else if (frame_type == 247) { 2934 stackmap_p += 2; 2935 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2936 calc_number_of_entries, frame_type, THREAD); 2937 } 2938 2939 // chop_frame { 2940 // u1 frame_type = CHOP; /* 248-250 */ 2941 // u2 offset_delta; 2942 // } 2943 else if (frame_type >= 248 && frame_type <= 250) { 2944 stackmap_p += 2; 2945 } 2946 2947 // same_frame_extended { 2948 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/ 2949 // u2 offset_delta; 2950 // } 2951 else if (frame_type == 251) { 2952 stackmap_p += 2; 2953 } 2954 2955 // append_frame { 2956 // u1 frame_type = APPEND; /* 252-254 */ 2957 // u2 offset_delta; 2958 // verification_type_info locals[frame_type - 251]; 2959 // } 2960 else if (frame_type >= 252 && frame_type <= 254) { 2961 assert(stackmap_p + 2 <= stackmap_end, 2962 "no room for offset_delta"); 2963 stackmap_p += 2; 2964 u1 len = frame_type - 251; 2965 for (u1 i = 0; i < len; i++) { 2966 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2967 calc_number_of_entries, frame_type, THREAD); 2968 } 2969 } 2970 2971 // full_frame { 2972 // u1 frame_type = FULL_FRAME; /* 255 */ 2973 // u2 offset_delta; 2974 // u2 number_of_locals; 2975 // verification_type_info locals[number_of_locals]; 2976 // u2 number_of_stack_items; 2977 // verification_type_info stack[number_of_stack_items]; 2978 // } 2979 else if (frame_type == 255) { 2980 assert(stackmap_p + 2 + 2 <= stackmap_end, 2981 "no room for smallest full_frame"); 2982 stackmap_p += 2; 2983 2984 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p); 2985 stackmap_p += 2; 2986 2987 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) { 2988 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2989 calc_number_of_entries, frame_type, THREAD); 2990 } 2991 2992 // Use the largest size for the number_of_stack_items, but only get 2993 // the right number of bytes. 2994 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p); 2995 stackmap_p += 2; 2996 2997 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) { 2998 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2999 calc_number_of_entries, frame_type, THREAD); 3000 } 3001 } 3002 } // end while there is a stack_map_frame 3003 assert(number_of_entries == calc_number_of_entries, "sanity check"); 3004 } // end rewrite_cp_refs_in_stack_map_table() 3005 3006 3007 // Rewrite constant pool references in the verification type info 3008 // portion of the method's stackmap table. These "structures" are 3009 // adapted from the StackMapTable_attribute that is described in 3010 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26): 3011 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf 3012 // 3013 // The verification_type_info structure is a u1 tag followed by 0 or 3014 // more bytes of data: 3015 // 3016 // union verification_type_info { 3017 // Top_variable_info; 3018 // Integer_variable_info; 3019 // Float_variable_info; 3020 // Long_variable_info; 3021 // Double_variable_info; 3022 // Null_variable_info; 3023 // UninitializedThis_variable_info; 3024 // Object_variable_info; 3025 // Uninitialized_variable_info; 3026 // } 3027 // 3028 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info( 3029 address& stackmap_p_ref, address stackmap_end, u2 frame_i, 3030 u1 frame_type, TRAPS) { 3031 3032 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag"); 3033 u1 tag = *stackmap_p_ref; 3034 stackmap_p_ref++; 3035 3036 switch (tag) { 3037 // Top_variable_info { 3038 // u1 tag = ITEM_Top; /* 0 */ 3039 // } 3040 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top 3041 case 0: // fall through 3042 3043 // Integer_variable_info { 3044 // u1 tag = ITEM_Integer; /* 1 */ 3045 // } 3046 case ITEM_Integer: // fall through 3047 3048 // Float_variable_info { 3049 // u1 tag = ITEM_Float; /* 2 */ 3050 // } 3051 case ITEM_Float: // fall through 3052 3053 // Double_variable_info { 3054 // u1 tag = ITEM_Double; /* 3 */ 3055 // } 3056 case ITEM_Double: // fall through 3057 3058 // Long_variable_info { 3059 // u1 tag = ITEM_Long; /* 4 */ 3060 // } 3061 case ITEM_Long: // fall through 3062 3063 // Null_variable_info { 3064 // u1 tag = ITEM_Null; /* 5 */ 3065 // } 3066 case ITEM_Null: // fall through 3067 3068 // UninitializedThis_variable_info { 3069 // u1 tag = ITEM_UninitializedThis; /* 6 */ 3070 // } 3071 case ITEM_UninitializedThis: 3072 // nothing more to do for the above tag types 3073 break; 3074 3075 // Object_variable_info { 3076 // u1 tag = ITEM_Object; /* 7 */ 3077 // u2 cpool_index; 3078 // } 3079 case ITEM_Object: 3080 { 3081 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index"); 3082 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref); 3083 u2 new_cp_index = find_new_index(cpool_index); 3084 if (new_cp_index != 0) { 3085 RC_TRACE_WITH_THREAD(0x04000000, THREAD, 3086 ("mapped old cpool_index=%d", cpool_index)); 3087 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index); 3088 cpool_index = new_cp_index; 3089 } 3090 stackmap_p_ref += 2; 3091 3092 RC_TRACE_WITH_THREAD(0x04000000, THREAD, 3093 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i, 3094 frame_type, cpool_index)); 3095 } break; 3096 3097 // Uninitialized_variable_info { 3098 // u1 tag = ITEM_Uninitialized; /* 8 */ 3099 // u2 offset; 3100 // } 3101 case ITEM_Uninitialized: 3102 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset"); 3103 stackmap_p_ref += 2; 3104 break; 3105 3106 default: 3107 RC_TRACE_WITH_THREAD(0x04000000, THREAD, 3108 ("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag)); 3109 ShouldNotReachHere(); 3110 break; 3111 } // end switch (tag) 3112 } // end rewrite_cp_refs_in_verification_type_info() 3113 3114 3115 // Change the constant pool associated with klass scratch_class to 3116 // scratch_cp. If shrink is true, then scratch_cp_length elements 3117 // are copied from scratch_cp to a smaller constant pool and the 3118 // smaller constant pool is associated with scratch_class. 3119 void VM_RedefineClasses::set_new_constant_pool( 3120 ClassLoaderData* loader_data, 3121 instanceKlassHandle scratch_class, constantPoolHandle scratch_cp, 3122 int scratch_cp_length, TRAPS) { 3123 assert(scratch_cp->length() >= scratch_cp_length, "sanity check"); 3124 3125 // scratch_cp is a merged constant pool and has enough space for a 3126 // worst case merge situation. We want to associate the minimum 3127 // sized constant pool with the klass to save space. 3128 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK); 3129 constantPoolHandle smaller_cp(THREAD, cp); 3130 3131 // preserve version() value in the smaller copy 3132 int version = scratch_cp->version(); 3133 assert(version != 0, "sanity check"); 3134 smaller_cp->set_version(version); 3135 3136 // attach klass to new constant pool 3137 // reference to the cp holder is needed for copy_operands() 3138 smaller_cp->set_pool_holder(scratch_class()); 3139 3140 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD); 3141 if (HAS_PENDING_EXCEPTION) { 3142 // Exception is handled in the caller 3143 loader_data->add_to_deallocate_list(smaller_cp()); 3144 return; 3145 } 3146 scratch_cp = smaller_cp; 3147 3148 // attach new constant pool to klass 3149 scratch_class->set_constants(scratch_cp()); 3150 3151 int i; // for portability 3152 3153 // update each field in klass to use new constant pool indices as needed 3154 for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) { 3155 jshort cur_index = fs.name_index(); 3156 jshort new_index = find_new_index(cur_index); 3157 if (new_index != 0) { 3158 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3159 ("field-name_index change: %d to %d", cur_index, new_index)); 3160 fs.set_name_index(new_index); 3161 } 3162 cur_index = fs.signature_index(); 3163 new_index = find_new_index(cur_index); 3164 if (new_index != 0) { 3165 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3166 ("field-signature_index change: %d to %d", cur_index, new_index)); 3167 fs.set_signature_index(new_index); 3168 } 3169 cur_index = fs.initval_index(); 3170 new_index = find_new_index(cur_index); 3171 if (new_index != 0) { 3172 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3173 ("field-initval_index change: %d to %d", cur_index, new_index)); 3174 fs.set_initval_index(new_index); 3175 } 3176 cur_index = fs.generic_signature_index(); 3177 new_index = find_new_index(cur_index); 3178 if (new_index != 0) { 3179 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3180 ("field-generic_signature change: %d to %d", cur_index, new_index)); 3181 fs.set_generic_signature_index(new_index); 3182 } 3183 } // end for each field 3184 3185 // Update constant pool indices in the inner classes info to use 3186 // new constant indices as needed. The inner classes info is a 3187 // quadruple: 3188 // (inner_class_info, outer_class_info, inner_name, inner_access_flags) 3189 InnerClassesIterator iter(scratch_class); 3190 for (; !iter.done(); iter.next()) { 3191 int cur_index = iter.inner_class_info_index(); 3192 if (cur_index == 0) { 3193 continue; // JVM spec. allows null inner class refs so skip it 3194 } 3195 int new_index = find_new_index(cur_index); 3196 if (new_index != 0) { 3197 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3198 ("inner_class_info change: %d to %d", cur_index, new_index)); 3199 iter.set_inner_class_info_index(new_index); 3200 } 3201 cur_index = iter.outer_class_info_index(); 3202 new_index = find_new_index(cur_index); 3203 if (new_index != 0) { 3204 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3205 ("outer_class_info change: %d to %d", cur_index, new_index)); 3206 iter.set_outer_class_info_index(new_index); 3207 } 3208 cur_index = iter.inner_name_index(); 3209 new_index = find_new_index(cur_index); 3210 if (new_index != 0) { 3211 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3212 ("inner_name change: %d to %d", cur_index, new_index)); 3213 iter.set_inner_name_index(new_index); 3214 } 3215 } // end for each inner class 3216 3217 // Attach each method in klass to the new constant pool and update 3218 // to use new constant pool indices as needed: 3219 Array<Method*>* methods = scratch_class->methods(); 3220 for (i = methods->length() - 1; i >= 0; i--) { 3221 methodHandle method(THREAD, methods->at(i)); 3222 method->set_constants(scratch_cp()); 3223 3224 int new_index = find_new_index(method->name_index()); 3225 if (new_index != 0) { 3226 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3227 ("method-name_index change: %d to %d", method->name_index(), 3228 new_index)); 3229 method->set_name_index(new_index); 3230 } 3231 new_index = find_new_index(method->signature_index()); 3232 if (new_index != 0) { 3233 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3234 ("method-signature_index change: %d to %d", 3235 method->signature_index(), new_index)); 3236 method->set_signature_index(new_index); 3237 } 3238 new_index = find_new_index(method->generic_signature_index()); 3239 if (new_index != 0) { 3240 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3241 ("method-generic_signature_index change: %d to %d", 3242 method->generic_signature_index(), new_index)); 3243 method->set_generic_signature_index(new_index); 3244 } 3245 3246 // Update constant pool indices in the method's checked exception 3247 // table to use new constant indices as needed. 3248 int cext_length = method->checked_exceptions_length(); 3249 if (cext_length > 0) { 3250 CheckedExceptionElement * cext_table = 3251 method->checked_exceptions_start(); 3252 for (int j = 0; j < cext_length; j++) { 3253 int cur_index = cext_table[j].class_cp_index; 3254 int new_index = find_new_index(cur_index); 3255 if (new_index != 0) { 3256 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3257 ("cext-class_cp_index change: %d to %d", cur_index, new_index)); 3258 cext_table[j].class_cp_index = (u2)new_index; 3259 } 3260 } // end for each checked exception table entry 3261 } // end if there are checked exception table entries 3262 3263 // Update each catch type index in the method's exception table 3264 // to use new constant pool indices as needed. The exception table 3265 // holds quadruple entries of the form: 3266 // (beg_bci, end_bci, handler_bci, klass_index) 3267 3268 ExceptionTable ex_table(method()); 3269 int ext_length = ex_table.length(); 3270 3271 for (int j = 0; j < ext_length; j ++) { 3272 int cur_index = ex_table.catch_type_index(j); 3273 int new_index = find_new_index(cur_index); 3274 if (new_index != 0) { 3275 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3276 ("ext-klass_index change: %d to %d", cur_index, new_index)); 3277 ex_table.set_catch_type_index(j, new_index); 3278 } 3279 } // end for each exception table entry 3280 3281 // Update constant pool indices in the method's local variable 3282 // table to use new constant indices as needed. The local variable 3283 // table hold sextuple entries of the form: 3284 // (start_pc, length, name_index, descriptor_index, signature_index, slot) 3285 int lvt_length = method->localvariable_table_length(); 3286 if (lvt_length > 0) { 3287 LocalVariableTableElement * lv_table = 3288 method->localvariable_table_start(); 3289 for (int j = 0; j < lvt_length; j++) { 3290 int cur_index = lv_table[j].name_cp_index; 3291 int new_index = find_new_index(cur_index); 3292 if (new_index != 0) { 3293 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3294 ("lvt-name_cp_index change: %d to %d", cur_index, new_index)); 3295 lv_table[j].name_cp_index = (u2)new_index; 3296 } 3297 cur_index = lv_table[j].descriptor_cp_index; 3298 new_index = find_new_index(cur_index); 3299 if (new_index != 0) { 3300 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3301 ("lvt-descriptor_cp_index change: %d to %d", cur_index, 3302 new_index)); 3303 lv_table[j].descriptor_cp_index = (u2)new_index; 3304 } 3305 cur_index = lv_table[j].signature_cp_index; 3306 new_index = find_new_index(cur_index); 3307 if (new_index != 0) { 3308 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3309 ("lvt-signature_cp_index change: %d to %d", cur_index, new_index)); 3310 lv_table[j].signature_cp_index = (u2)new_index; 3311 } 3312 } // end for each local variable table entry 3313 } // end if there are local variable table entries 3314 3315 rewrite_cp_refs_in_stack_map_table(method, THREAD); 3316 } // end for each method 3317 } // end set_new_constant_pool() 3318 3319 3320 // Unevolving classes may point to methods of the_class directly 3321 // from their constant pool caches, itables, and/or vtables. We 3322 // use the ClassLoaderDataGraph::classes_do() facility and this helper 3323 // to fix up these pointers. 3324 3325 // Adjust cpools and vtables closure 3326 void VM_RedefineClasses::AdjustCpoolCacheAndVtable::do_klass(Klass* k) { 3327 3328 // This is a very busy routine. We don't want too much tracing 3329 // printed out. 3330 bool trace_name_printed = false; 3331 InstanceKlass *the_class = InstanceKlass::cast(_the_class_oop); 3332 3333 // Very noisy: only enable this call if you are trying to determine 3334 // that a specific class gets found by this routine. 3335 // RC_TRACE macro has an embedded ResourceMark 3336 // RC_TRACE_WITH_THREAD(0x00100000, THREAD, 3337 // ("adjust check: name=%s", k->external_name())); 3338 // trace_name_printed = true; 3339 3340 // If the class being redefined is java.lang.Object, we need to fix all 3341 // array class vtables also 3342 if (k->oop_is_array() && _the_class_oop == SystemDictionary::Object_klass()) { 3343 k->vtable()->adjust_method_entries(the_class, &trace_name_printed); 3344 3345 } else if (k->oop_is_instance()) { 3346 HandleMark hm(_thread); 3347 InstanceKlass *ik = InstanceKlass::cast(k); 3348 3349 // HotSpot specific optimization! HotSpot does not currently 3350 // support delegation from the bootstrap class loader to a 3351 // user-defined class loader. This means that if the bootstrap 3352 // class loader is the initiating class loader, then it will also 3353 // be the defining class loader. This also means that classes 3354 // loaded by the bootstrap class loader cannot refer to classes 3355 // loaded by a user-defined class loader. Note: a user-defined 3356 // class loader can delegate to the bootstrap class loader. 3357 // 3358 // If the current class being redefined has a user-defined class 3359 // loader as its defining class loader, then we can skip all 3360 // classes loaded by the bootstrap class loader. 3361 bool is_user_defined = 3362 InstanceKlass::cast(_the_class_oop)->class_loader() != NULL; 3363 if (is_user_defined && ik->class_loader() == NULL) { 3364 return; 3365 } 3366 3367 // Fix the vtable embedded in the_class and subclasses of the_class, 3368 // if one exists. We discard scratch_class and we don't keep an 3369 // InstanceKlass around to hold obsolete methods so we don't have 3370 // any other InstanceKlass embedded vtables to update. The vtable 3371 // holds the Method*s for virtual (but not final) methods. 3372 // Default methods, or concrete methods in interfaces are stored 3373 // in the vtable, so if an interface changes we need to check 3374 // adjust_method_entries() for every InstanceKlass, which will also 3375 // adjust the default method vtable indices. 3376 // We also need to adjust any default method entries that are 3377 // not yet in the vtable, because the vtable setup is in progress. 3378 // This must be done after we adjust the default_methods and 3379 // default_vtable_indices for methods already in the vtable. 3380 // If redefining Unsafe, walk all the vtables looking for entries. 3381 if (ik->vtable_length() > 0 && (_the_class_oop->is_interface() 3382 || _the_class_oop == SystemDictionary::misc_Unsafe_klass() 3383 || ik->is_subtype_of(_the_class_oop))) { 3384 // ik->vtable() creates a wrapper object; rm cleans it up 3385 ResourceMark rm(_thread); 3386 3387 ik->vtable()->adjust_method_entries(the_class, &trace_name_printed); 3388 ik->adjust_default_methods(the_class, &trace_name_printed); 3389 } 3390 3391 // If the current class has an itable and we are either redefining an 3392 // interface or if the current class is a subclass of the_class, then 3393 // we potentially have to fix the itable. If we are redefining an 3394 // interface, then we have to call adjust_method_entries() for 3395 // every InstanceKlass that has an itable since there isn't a 3396 // subclass relationship between an interface and an InstanceKlass. 3397 // If redefining Unsafe, walk all the itables looking for entries. 3398 if (ik->itable_length() > 0 && (_the_class_oop->is_interface() 3399 || _the_class_oop == SystemDictionary::misc_Unsafe_klass() 3400 || ik->is_subclass_of(_the_class_oop))) { 3401 // ik->itable() creates a wrapper object; rm cleans it up 3402 ResourceMark rm(_thread); 3403 3404 ik->itable()->adjust_method_entries(the_class, &trace_name_printed); 3405 } 3406 3407 // The constant pools in other classes (other_cp) can refer to 3408 // methods in the_class. We have to update method information in 3409 // other_cp's cache. If other_cp has a previous version, then we 3410 // have to repeat the process for each previous version. The 3411 // constant pool cache holds the Method*s for non-virtual 3412 // methods and for virtual, final methods. 3413 // 3414 // Special case: if the current class is the_class, then new_cp 3415 // has already been attached to the_class and old_cp has already 3416 // been added as a previous version. The new_cp doesn't have any 3417 // cached references to old methods so it doesn't need to be 3418 // updated. We can simply start with the previous version(s) in 3419 // that case. 3420 constantPoolHandle other_cp; 3421 ConstantPoolCache* cp_cache; 3422 3423 if (ik != _the_class_oop) { 3424 // this klass' constant pool cache may need adjustment 3425 other_cp = constantPoolHandle(ik->constants()); 3426 cp_cache = other_cp->cache(); 3427 if (cp_cache != NULL) { 3428 cp_cache->adjust_method_entries(the_class, &trace_name_printed); 3429 } 3430 } 3431 3432 // the previous versions' constant pool caches may need adjustment 3433 for (InstanceKlass* pv_node = ik->previous_versions(); 3434 pv_node != NULL; 3435 pv_node = pv_node->previous_versions()) { 3436 cp_cache = pv_node->constants()->cache(); 3437 if (cp_cache != NULL) { 3438 cp_cache->adjust_method_entries(pv_node, &trace_name_printed); 3439 } 3440 } 3441 } 3442 } 3443 3444 // Clean method data for this class 3445 void VM_RedefineClasses::MethodDataCleaner::do_klass(Klass* k) { 3446 if (k->oop_is_instance()) { 3447 InstanceKlass *ik = InstanceKlass::cast(k); 3448 // Clean MethodData of this class's methods so they don't refer to 3449 // old methods that are no longer running. 3450 Array<Method*>* methods = ik->methods(); 3451 int num_methods = methods->length(); 3452 for (int index = 0; index < num_methods; ++index) { 3453 if (methods->at(index)->method_data() != NULL) { 3454 methods->at(index)->method_data()->clean_weak_method_links(); 3455 } 3456 } 3457 } 3458 } 3459 3460 void VM_RedefineClasses::update_jmethod_ids() { 3461 for (int j = 0; j < _matching_methods_length; ++j) { 3462 Method* old_method = _matching_old_methods[j]; 3463 jmethodID jmid = old_method->find_jmethod_id_or_null(); 3464 if (jmid != NULL) { 3465 // There is a jmethodID, change it to point to the new method 3466 methodHandle new_method_h(_matching_new_methods[j]); 3467 Method::change_method_associated_with_jmethod_id(jmid, new_method_h()); 3468 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j], 3469 "should be replaced"); 3470 } 3471 } 3472 } 3473 3474 int VM_RedefineClasses::check_methods_and_mark_as_obsolete() { 3475 int emcp_method_count = 0; 3476 int obsolete_count = 0; 3477 int old_index = 0; 3478 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) { 3479 Method* old_method = _matching_old_methods[j]; 3480 Method* new_method = _matching_new_methods[j]; 3481 Method* old_array_method; 3482 3483 // Maintain an old_index into the _old_methods array by skipping 3484 // deleted methods 3485 while ((old_array_method = _old_methods->at(old_index)) != old_method) { 3486 ++old_index; 3487 } 3488 3489 if (MethodComparator::methods_EMCP(old_method, new_method)) { 3490 // The EMCP definition from JSR-163 requires the bytecodes to be 3491 // the same with the exception of constant pool indices which may 3492 // differ. However, the constants referred to by those indices 3493 // must be the same. 3494 // 3495 // We use methods_EMCP() for comparison since constant pool 3496 // merging can remove duplicate constant pool entries that were 3497 // present in the old method and removed from the rewritten new 3498 // method. A faster binary comparison function would consider the 3499 // old and new methods to be different when they are actually 3500 // EMCP. 3501 // 3502 // The old and new methods are EMCP and you would think that we 3503 // could get rid of one of them here and now and save some space. 3504 // However, the concept of EMCP only considers the bytecodes and 3505 // the constant pool entries in the comparison. Other things, 3506 // e.g., the line number table (LNT) or the local variable table 3507 // (LVT) don't count in the comparison. So the new (and EMCP) 3508 // method can have a new LNT that we need so we can't just 3509 // overwrite the new method with the old method. 3510 // 3511 // When this routine is called, we have already attached the new 3512 // methods to the_class so the old methods are effectively 3513 // overwritten. However, if an old method is still executing, 3514 // then the old method cannot be collected until sometime after 3515 // the old method call has returned. So the overwriting of old 3516 // methods by new methods will save us space except for those 3517 // (hopefully few) old methods that are still executing. 3518 // 3519 // A method refers to a ConstMethod* and this presents another 3520 // possible avenue to space savings. The ConstMethod* in the 3521 // new method contains possibly new attributes (LNT, LVT, etc). 3522 // At first glance, it seems possible to save space by replacing 3523 // the ConstMethod* in the old method with the ConstMethod* 3524 // from the new method. The old and new methods would share the 3525 // same ConstMethod* and we would save the space occupied by 3526 // the old ConstMethod*. However, the ConstMethod* contains 3527 // a back reference to the containing method. Sharing the 3528 // ConstMethod* between two methods could lead to confusion in 3529 // the code that uses the back reference. This would lead to 3530 // brittle code that could be broken in non-obvious ways now or 3531 // in the future. 3532 // 3533 // Another possibility is to copy the ConstMethod* from the new 3534 // method to the old method and then overwrite the new method with 3535 // the old method. Since the ConstMethod* contains the bytecodes 3536 // for the method embedded in the oop, this option would change 3537 // the bytecodes out from under any threads executing the old 3538 // method and make the thread's bcp invalid. Since EMCP requires 3539 // that the bytecodes be the same modulo constant pool indices, it 3540 // is straight forward to compute the correct new bcp in the new 3541 // ConstMethod* from the old bcp in the old ConstMethod*. The 3542 // time consuming part would be searching all the frames in all 3543 // of the threads to find all of the calls to the old method. 3544 // 3545 // It looks like we will have to live with the limited savings 3546 // that we get from effectively overwriting the old methods 3547 // when the new methods are attached to the_class. 3548 3549 // Count number of methods that are EMCP. The method will be marked 3550 // old but not obsolete if it is EMCP. 3551 emcp_method_count++; 3552 3553 // An EMCP method is _not_ obsolete. An obsolete method has a 3554 // different jmethodID than the current method. An EMCP method 3555 // has the same jmethodID as the current method. Having the 3556 // same jmethodID for all EMCP versions of a method allows for 3557 // a consistent view of the EMCP methods regardless of which 3558 // EMCP method you happen to have in hand. For example, a 3559 // breakpoint set in one EMCP method will work for all EMCP 3560 // versions of the method including the current one. 3561 } else { 3562 // mark obsolete methods as such 3563 old_method->set_is_obsolete(); 3564 obsolete_count++; 3565 3566 // obsolete methods need a unique idnum so they become new entries in 3567 // the jmethodID cache in InstanceKlass 3568 assert(old_method->method_idnum() == new_method->method_idnum(), "must match"); 3569 u2 num = InstanceKlass::cast(_the_class_oop)->next_method_idnum(); 3570 if (num != ConstMethod::UNSET_IDNUM) { 3571 old_method->set_method_idnum(num); 3572 } 3573 3574 // With tracing we try not to "yack" too much. The position of 3575 // this trace assumes there are fewer obsolete methods than 3576 // EMCP methods. 3577 RC_TRACE(0x00000100, ("mark %s(%s) as obsolete", 3578 old_method->name()->as_C_string(), 3579 old_method->signature()->as_C_string())); 3580 } 3581 old_method->set_is_old(); 3582 } 3583 for (int i = 0; i < _deleted_methods_length; ++i) { 3584 Method* old_method = _deleted_methods[i]; 3585 3586 assert(!old_method->has_vtable_index(), 3587 "cannot delete methods with vtable entries");; 3588 3589 // Mark all deleted methods as old, obsolete and deleted 3590 old_method->set_is_deleted(); 3591 old_method->set_is_old(); 3592 old_method->set_is_obsolete(); 3593 ++obsolete_count; 3594 // With tracing we try not to "yack" too much. The position of 3595 // this trace assumes there are fewer obsolete methods than 3596 // EMCP methods. 3597 RC_TRACE(0x00000100, ("mark deleted %s(%s) as obsolete", 3598 old_method->name()->as_C_string(), 3599 old_method->signature()->as_C_string())); 3600 } 3601 assert((emcp_method_count + obsolete_count) == _old_methods->length(), 3602 "sanity check"); 3603 RC_TRACE(0x00000100, ("EMCP_cnt=%d, obsolete_cnt=%d", emcp_method_count, 3604 obsolete_count)); 3605 return emcp_method_count; 3606 } 3607 3608 // This internal class transfers the native function registration from old methods 3609 // to new methods. It is designed to handle both the simple case of unchanged 3610 // native methods and the complex cases of native method prefixes being added and/or 3611 // removed. 3612 // It expects only to be used during the VM_RedefineClasses op (a safepoint). 3613 // 3614 // This class is used after the new methods have been installed in "the_class". 3615 // 3616 // So, for example, the following must be handled. Where 'm' is a method and 3617 // a number followed by an underscore is a prefix. 3618 // 3619 // Old Name New Name 3620 // Simple transfer to new method m -> m 3621 // Add prefix m -> 1_m 3622 // Remove prefix 1_m -> m 3623 // Simultaneous add of prefixes m -> 3_2_1_m 3624 // Simultaneous removal of prefixes 3_2_1_m -> m 3625 // Simultaneous add and remove 1_m -> 2_m 3626 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m 3627 // 3628 class TransferNativeFunctionRegistration { 3629 private: 3630 instanceKlassHandle the_class; 3631 int prefix_count; 3632 char** prefixes; 3633 3634 // Recursively search the binary tree of possibly prefixed method names. 3635 // Iteration could be used if all agents were well behaved. Full tree walk is 3636 // more resilent to agents not cleaning up intermediate methods. 3637 // Branch at each depth in the binary tree is: 3638 // (1) without the prefix. 3639 // (2) with the prefix. 3640 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...) 3641 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len, 3642 Symbol* signature) { 3643 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len); 3644 if (name_symbol != NULL) { 3645 Method* method = the_class()->lookup_method(name_symbol, signature); 3646 if (method != NULL) { 3647 // Even if prefixed, intermediate methods must exist. 3648 if (method->is_native()) { 3649 // Wahoo, we found a (possibly prefixed) version of the method, return it. 3650 return method; 3651 } 3652 if (depth < prefix_count) { 3653 // Try applying further prefixes (other than this one). 3654 method = search_prefix_name_space(depth+1, name_str, name_len, signature); 3655 if (method != NULL) { 3656 return method; // found 3657 } 3658 3659 // Try adding this prefix to the method name and see if it matches 3660 // another method name. 3661 char* prefix = prefixes[depth]; 3662 size_t prefix_len = strlen(prefix); 3663 size_t trial_len = name_len + prefix_len; 3664 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1); 3665 strcpy(trial_name_str, prefix); 3666 strcat(trial_name_str, name_str); 3667 method = search_prefix_name_space(depth+1, trial_name_str, trial_len, 3668 signature); 3669 if (method != NULL) { 3670 // If found along this branch, it was prefixed, mark as such 3671 method->set_is_prefixed_native(); 3672 return method; // found 3673 } 3674 } 3675 } 3676 } 3677 return NULL; // This whole branch bore nothing 3678 } 3679 3680 // Return the method name with old prefixes stripped away. 3681 char* method_name_without_prefixes(Method* method) { 3682 Symbol* name = method->name(); 3683 char* name_str = name->as_utf8(); 3684 3685 // Old prefixing may be defunct, strip prefixes, if any. 3686 for (int i = prefix_count-1; i >= 0; i--) { 3687 char* prefix = prefixes[i]; 3688 size_t prefix_len = strlen(prefix); 3689 if (strncmp(prefix, name_str, prefix_len) == 0) { 3690 name_str += prefix_len; 3691 } 3692 } 3693 return name_str; 3694 } 3695 3696 // Strip any prefixes off the old native method, then try to find a 3697 // (possibly prefixed) new native that matches it. 3698 Method* strip_and_search_for_new_native(Method* method) { 3699 ResourceMark rm; 3700 char* name_str = method_name_without_prefixes(method); 3701 return search_prefix_name_space(0, name_str, strlen(name_str), 3702 method->signature()); 3703 } 3704 3705 public: 3706 3707 // Construct a native method transfer processor for this class. 3708 TransferNativeFunctionRegistration(instanceKlassHandle _the_class) { 3709 assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); 3710 3711 the_class = _the_class; 3712 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count); 3713 } 3714 3715 // Attempt to transfer any of the old or deleted methods that are native 3716 void transfer_registrations(Method** old_methods, int methods_length) { 3717 for (int j = 0; j < methods_length; j++) { 3718 Method* old_method = old_methods[j]; 3719 3720 if (old_method->is_native() && old_method->has_native_function()) { 3721 Method* new_method = strip_and_search_for_new_native(old_method); 3722 if (new_method != NULL) { 3723 // Actually set the native function in the new method. 3724 // Redefine does not send events (except CFLH), certainly not this 3725 // behind the scenes re-registration. 3726 new_method->set_native_function(old_method->native_function(), 3727 !Method::native_bind_event_is_interesting); 3728 } 3729 } 3730 } 3731 } 3732 }; 3733 3734 // Don't lose the association between a native method and its JNI function. 3735 void VM_RedefineClasses::transfer_old_native_function_registrations(instanceKlassHandle the_class) { 3736 TransferNativeFunctionRegistration transfer(the_class); 3737 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length); 3738 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length); 3739 } 3740 3741 // Deoptimize all compiled code that depends on this class. 3742 // 3743 // If the can_redefine_classes capability is obtained in the onload 3744 // phase then the compiler has recorded all dependencies from startup. 3745 // In that case we need only deoptimize and throw away all compiled code 3746 // that depends on the class. 3747 // 3748 // If can_redefine_classes is obtained sometime after the onload 3749 // phase then the dependency information may be incomplete. In that case 3750 // the first call to RedefineClasses causes all compiled code to be 3751 // thrown away. As can_redefine_classes has been obtained then 3752 // all future compilations will record dependencies so second and 3753 // subsequent calls to RedefineClasses need only throw away code 3754 // that depends on the class. 3755 // 3756 void VM_RedefineClasses::flush_dependent_code(instanceKlassHandle k_h, TRAPS) { 3757 assert_locked_or_safepoint(Compile_lock); 3758 3759 // All dependencies have been recorded from startup or this is a second or 3760 // subsequent use of RedefineClasses 3761 if (JvmtiExport::all_dependencies_are_recorded()) { 3762 CodeCache::flush_evol_dependents_on(k_h); 3763 } else { 3764 CodeCache::mark_all_nmethods_for_deoptimization(); 3765 3766 ResourceMark rm(THREAD); 3767 DeoptimizationMarker dm; 3768 3769 // Deoptimize all activations depending on marked nmethods 3770 Deoptimization::deoptimize_dependents(); 3771 3772 // Make the dependent methods not entrant 3773 CodeCache::make_marked_nmethods_not_entrant(); 3774 3775 // From now on we know that the dependency information is complete 3776 JvmtiExport::set_all_dependencies_are_recorded(true); 3777 } 3778 } 3779 3780 void VM_RedefineClasses::compute_added_deleted_matching_methods() { 3781 Method* old_method; 3782 Method* new_method; 3783 3784 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 3785 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 3786 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length()); 3787 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 3788 3789 _matching_methods_length = 0; 3790 _deleted_methods_length = 0; 3791 _added_methods_length = 0; 3792 3793 int nj = 0; 3794 int oj = 0; 3795 while (true) { 3796 if (oj >= _old_methods->length()) { 3797 if (nj >= _new_methods->length()) { 3798 break; // we've looked at everything, done 3799 } 3800 // New method at the end 3801 new_method = _new_methods->at(nj); 3802 _added_methods[_added_methods_length++] = new_method; 3803 ++nj; 3804 } else if (nj >= _new_methods->length()) { 3805 // Old method, at the end, is deleted 3806 old_method = _old_methods->at(oj); 3807 _deleted_methods[_deleted_methods_length++] = old_method; 3808 ++oj; 3809 } else { 3810 old_method = _old_methods->at(oj); 3811 new_method = _new_methods->at(nj); 3812 if (old_method->name() == new_method->name()) { 3813 if (old_method->signature() == new_method->signature()) { 3814 _matching_old_methods[_matching_methods_length ] = old_method; 3815 _matching_new_methods[_matching_methods_length++] = new_method; 3816 ++nj; 3817 ++oj; 3818 } else { 3819 // added overloaded have already been moved to the end, 3820 // so this is a deleted overloaded method 3821 _deleted_methods[_deleted_methods_length++] = old_method; 3822 ++oj; 3823 } 3824 } else { // names don't match 3825 if (old_method->name()->fast_compare(new_method->name()) > 0) { 3826 // new method 3827 _added_methods[_added_methods_length++] = new_method; 3828 ++nj; 3829 } else { 3830 // deleted method 3831 _deleted_methods[_deleted_methods_length++] = old_method; 3832 ++oj; 3833 } 3834 } 3835 } 3836 } 3837 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity"); 3838 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity"); 3839 } 3840 3841 3842 void VM_RedefineClasses::swap_annotations(instanceKlassHandle the_class, 3843 instanceKlassHandle scratch_class) { 3844 // Swap annotation fields values 3845 Annotations* old_annotations = the_class->annotations(); 3846 the_class->set_annotations(scratch_class->annotations()); 3847 scratch_class->set_annotations(old_annotations); 3848 } 3849 3850 3851 // Install the redefinition of a class: 3852 // - house keeping (flushing breakpoints and caches, deoptimizing 3853 // dependent compiled code) 3854 // - replacing parts in the_class with parts from scratch_class 3855 // - adding a weak reference to track the obsolete but interesting 3856 // parts of the_class 3857 // - adjusting constant pool caches and vtables in other classes 3858 // that refer to methods in the_class. These adjustments use the 3859 // ClassLoaderDataGraph::classes_do() facility which only allows 3860 // a helper method to be specified. The interesting parameters 3861 // that we would like to pass to the helper method are saved in 3862 // static global fields in the VM operation. 3863 void VM_RedefineClasses::redefine_single_class(jclass the_jclass, 3864 Klass* scratch_class_oop, TRAPS) { 3865 3866 HandleMark hm(THREAD); // make sure handles from this call are freed 3867 RC_TIMER_START(_timer_rsc_phase1); 3868 3869 instanceKlassHandle scratch_class(scratch_class_oop); 3870 3871 oop the_class_mirror = JNIHandles::resolve_non_null(the_jclass); 3872 Klass* the_class_oop = java_lang_Class::as_Klass(the_class_mirror); 3873 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop); 3874 3875 // Remove all breakpoints in methods of this class 3876 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints(); 3877 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class_oop); 3878 3879 // Deoptimize all compiled code that depends on this class 3880 flush_dependent_code(the_class, THREAD); 3881 3882 _old_methods = the_class->methods(); 3883 _new_methods = scratch_class->methods(); 3884 _the_class_oop = the_class_oop; 3885 compute_added_deleted_matching_methods(); 3886 update_jmethod_ids(); 3887 3888 // Attach new constant pool to the original klass. The original 3889 // klass still refers to the old constant pool (for now). 3890 scratch_class->constants()->set_pool_holder(the_class()); 3891 3892 #if 0 3893 // In theory, with constant pool merging in place we should be able 3894 // to save space by using the new, merged constant pool in place of 3895 // the old constant pool(s). By "pool(s)" I mean the constant pool in 3896 // the klass version we are replacing now and any constant pool(s) in 3897 // previous versions of klass. Nice theory, doesn't work in practice. 3898 // When this code is enabled, even simple programs throw NullPointer 3899 // exceptions. I'm guessing that this is caused by some constant pool 3900 // cache difference between the new, merged constant pool and the 3901 // constant pool that was just being used by the klass. I'm keeping 3902 // this code around to archive the idea, but the code has to remain 3903 // disabled for now. 3904 3905 // Attach each old method to the new constant pool. This can be 3906 // done here since we are past the bytecode verification and 3907 // constant pool optimization phases. 3908 for (int i = _old_methods->length() - 1; i >= 0; i--) { 3909 Method* method = _old_methods->at(i); 3910 method->set_constants(scratch_class->constants()); 3911 } 3912 3913 { 3914 // walk all previous versions of the klass 3915 InstanceKlass *ik = (InstanceKlass *)the_class(); 3916 PreviousVersionWalker pvw(ik); 3917 instanceKlassHandle ikh; 3918 do { 3919 ikh = pvw.next_previous_version(); 3920 if (!ikh.is_null()) { 3921 ik = ikh(); 3922 3923 // attach previous version of klass to the new constant pool 3924 ik->set_constants(scratch_class->constants()); 3925 3926 // Attach each method in the previous version of klass to the 3927 // new constant pool 3928 Array<Method*>* prev_methods = ik->methods(); 3929 for (int i = prev_methods->length() - 1; i >= 0; i--) { 3930 Method* method = prev_methods->at(i); 3931 method->set_constants(scratch_class->constants()); 3932 } 3933 } 3934 } while (!ikh.is_null()); 3935 } 3936 #endif 3937 3938 // Replace methods and constantpool 3939 the_class->set_methods(_new_methods); 3940 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods, 3941 // and to be able to undo operation easily. 3942 3943 ConstantPool* old_constants = the_class->constants(); 3944 the_class->set_constants(scratch_class->constants()); 3945 scratch_class->set_constants(old_constants); // See the previous comment. 3946 #if 0 3947 // We are swapping the guts of "the new class" with the guts of "the 3948 // class". Since the old constant pool has just been attached to "the 3949 // new class", it seems logical to set the pool holder in the old 3950 // constant pool also. However, doing this will change the observable 3951 // class hierarchy for any old methods that are still executing. A 3952 // method can query the identity of its "holder" and this query uses 3953 // the method's constant pool link to find the holder. The change in 3954 // holding class from "the class" to "the new class" can confuse 3955 // things. 3956 // 3957 // Setting the old constant pool's holder will also cause 3958 // verification done during vtable initialization below to fail. 3959 // During vtable initialization, the vtable's class is verified to be 3960 // a subtype of the method's holder. The vtable's class is "the 3961 // class" and the method's holder is gotten from the constant pool 3962 // link in the method itself. For "the class"'s directly implemented 3963 // methods, the method holder is "the class" itself (as gotten from 3964 // the new constant pool). The check works fine in this case. The 3965 // check also works fine for methods inherited from super classes. 3966 // 3967 // Miranda methods are a little more complicated. A miranda method is 3968 // provided by an interface when the class implementing the interface 3969 // does not provide its own method. These interfaces are implemented 3970 // internally as an InstanceKlass. These special instanceKlasses 3971 // share the constant pool of the class that "implements" the 3972 // interface. By sharing the constant pool, the method holder of a 3973 // miranda method is the class that "implements" the interface. In a 3974 // non-redefine situation, the subtype check works fine. However, if 3975 // the old constant pool's pool holder is modified, then the check 3976 // fails because there is no class hierarchy relationship between the 3977 // vtable's class and "the new class". 3978 3979 old_constants->set_pool_holder(scratch_class()); 3980 #endif 3981 3982 // track number of methods that are EMCP for add_previous_version() call below 3983 int emcp_method_count = check_methods_and_mark_as_obsolete(); 3984 transfer_old_native_function_registrations(the_class); 3985 3986 // The class file bytes from before any retransformable agents mucked 3987 // with them was cached on the scratch class, move to the_class. 3988 // Note: we still want to do this if nothing needed caching since it 3989 // should get cleared in the_class too. 3990 if (the_class->get_cached_class_file_bytes() == 0) { 3991 // the_class doesn't have a cache yet so copy it 3992 the_class->set_cached_class_file(scratch_class->get_cached_class_file()); 3993 } 3994 else if (scratch_class->get_cached_class_file_bytes() != 3995 the_class->get_cached_class_file_bytes()) { 3996 // The same class can be present twice in the scratch classes list or there 3997 // are multiple concurrent RetransformClasses calls on different threads. 3998 // In such cases we have to deallocate scratch_class cached_class_file. 3999 os::free(scratch_class->get_cached_class_file()); 4000 } 4001 4002 // NULL out in scratch class to not delete twice. The class to be redefined 4003 // always owns these bytes. 4004 scratch_class->set_cached_class_file(NULL); 4005 4006 // Replace inner_classes 4007 Array<u2>* old_inner_classes = the_class->inner_classes(); 4008 the_class->set_inner_classes(scratch_class->inner_classes()); 4009 scratch_class->set_inner_classes(old_inner_classes); 4010 4011 // Initialize the vtable and interface table after 4012 // methods have been rewritten 4013 { 4014 ResourceMark rm(THREAD); 4015 // no exception should happen here since we explicitly 4016 // do not check loader constraints. 4017 // compare_and_normalize_class_versions has already checked: 4018 // - classloaders unchanged, signatures unchanged 4019 // - all instanceKlasses for redefined classes reused & contents updated 4020 the_class->vtable()->initialize_vtable(false, THREAD); 4021 the_class->itable()->initialize_itable(false, THREAD); 4022 assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())), "redefine exception"); 4023 } 4024 4025 // Leave arrays of jmethodIDs and itable index cache unchanged 4026 4027 // Copy the "source file name" attribute from new class version 4028 the_class->set_source_file_name_index( 4029 scratch_class->source_file_name_index()); 4030 4031 // Copy the "source debug extension" attribute from new class version 4032 the_class->set_source_debug_extension( 4033 scratch_class->source_debug_extension(), 4034 scratch_class->source_debug_extension() == NULL ? 0 : 4035 (int)strlen(scratch_class->source_debug_extension())); 4036 4037 // Use of javac -g could be different in the old and the new 4038 if (scratch_class->access_flags().has_localvariable_table() != 4039 the_class->access_flags().has_localvariable_table()) { 4040 4041 AccessFlags flags = the_class->access_flags(); 4042 if (scratch_class->access_flags().has_localvariable_table()) { 4043 flags.set_has_localvariable_table(); 4044 } else { 4045 flags.clear_has_localvariable_table(); 4046 } 4047 the_class->set_access_flags(flags); 4048 } 4049 4050 swap_annotations(the_class, scratch_class); 4051 4052 // Replace minor version number of class file 4053 u2 old_minor_version = the_class->minor_version(); 4054 the_class->set_minor_version(scratch_class->minor_version()); 4055 scratch_class->set_minor_version(old_minor_version); 4056 4057 // Replace major version number of class file 4058 u2 old_major_version = the_class->major_version(); 4059 the_class->set_major_version(scratch_class->major_version()); 4060 scratch_class->set_major_version(old_major_version); 4061 4062 // Replace CP indexes for class and name+type of enclosing method 4063 u2 old_class_idx = the_class->enclosing_method_class_index(); 4064 u2 old_method_idx = the_class->enclosing_method_method_index(); 4065 the_class->set_enclosing_method_indices( 4066 scratch_class->enclosing_method_class_index(), 4067 scratch_class->enclosing_method_method_index()); 4068 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx); 4069 4070 the_class->set_has_been_redefined(); 4071 4072 // keep track of previous versions of this class 4073 the_class->add_previous_version(scratch_class, emcp_method_count); 4074 4075 RC_TIMER_STOP(_timer_rsc_phase1); 4076 RC_TIMER_START(_timer_rsc_phase2); 4077 4078 // Adjust constantpool caches and vtables for all classes 4079 // that reference methods of the evolved class. 4080 AdjustCpoolCacheAndVtable adjust_cpool_cache_and_vtable(THREAD); 4081 ClassLoaderDataGraph::classes_do(&adjust_cpool_cache_and_vtable); 4082 4083 // JSR-292 support 4084 MemberNameTable* mnt = the_class->member_names(); 4085 if (mnt != NULL) { 4086 bool trace_name_printed = false; 4087 mnt->adjust_method_entries(the_class(), &trace_name_printed); 4088 } 4089 4090 if (the_class->oop_map_cache() != NULL) { 4091 // Flush references to any obsolete methods from the oop map cache 4092 // so that obsolete methods are not pinned. 4093 the_class->oop_map_cache()->flush_obsolete_entries(); 4094 } 4095 4096 // increment the classRedefinedCount field in the_class and in any 4097 // direct and indirect subclasses of the_class 4098 increment_class_counter((InstanceKlass *)the_class(), THREAD); 4099 4100 // RC_TRACE macro has an embedded ResourceMark 4101 RC_TRACE_WITH_THREAD(0x00000001, THREAD, 4102 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)", 4103 the_class->external_name(), 4104 java_lang_Class::classRedefinedCount(the_class_mirror), 4105 os::available_memory() >> 10)); 4106 4107 { 4108 ResourceMark rm(THREAD); 4109 Events::log_redefinition(THREAD, "redefined class name=%s, count=%d", 4110 the_class->external_name(), 4111 java_lang_Class::classRedefinedCount(the_class_mirror)); 4112 4113 } 4114 RC_TIMER_STOP(_timer_rsc_phase2); 4115 } // end redefine_single_class() 4116 4117 4118 // Increment the classRedefinedCount field in the specific InstanceKlass 4119 // and in all direct and indirect subclasses. 4120 void VM_RedefineClasses::increment_class_counter(InstanceKlass *ik, TRAPS) { 4121 oop class_mirror = ik->java_mirror(); 4122 Klass* class_oop = java_lang_Class::as_Klass(class_mirror); 4123 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1; 4124 java_lang_Class::set_classRedefinedCount(class_mirror, new_count); 4125 4126 if (class_oop != _the_class_oop) { 4127 // _the_class_oop count is printed at end of redefine_single_class() 4128 RC_TRACE_WITH_THREAD(0x00000008, THREAD, 4129 ("updated count in subclass=%s to %d", ik->external_name(), new_count)); 4130 } 4131 4132 for (Klass *subk = ik->subklass(); subk != NULL; 4133 subk = subk->next_sibling()) { 4134 if (subk->oop_is_instance()) { 4135 // Only update instanceKlasses 4136 InstanceKlass *subik = (InstanceKlass*)subk; 4137 // recursively do subclasses of the current subclass 4138 increment_class_counter(subik, THREAD); 4139 } 4140 } 4141 } 4142 4143 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) { 4144 bool no_old_methods = true; // be optimistic 4145 4146 // Both array and instance classes have vtables. 4147 // a vtable should never contain old or obsolete methods 4148 ResourceMark rm(_thread); 4149 if (k->vtable_length() > 0 && 4150 !k->vtable()->check_no_old_or_obsolete_entries()) { 4151 if (RC_TRACE_ENABLED(0x00004000)) { 4152 RC_TRACE_WITH_THREAD(0x00004000, _thread, 4153 ("klassVtable::check_no_old_or_obsolete_entries failure" 4154 " -- OLD or OBSOLETE method found -- class: %s", 4155 k->signature_name())); 4156 k->vtable()->dump_vtable(); 4157 } 4158 no_old_methods = false; 4159 } 4160 4161 if (k->oop_is_instance()) { 4162 HandleMark hm(_thread); 4163 InstanceKlass *ik = InstanceKlass::cast(k); 4164 4165 // an itable should never contain old or obsolete methods 4166 if (ik->itable_length() > 0 && 4167 !ik->itable()->check_no_old_or_obsolete_entries()) { 4168 if (RC_TRACE_ENABLED(0x00004000)) { 4169 RC_TRACE_WITH_THREAD(0x00004000, _thread, 4170 ("klassItable::check_no_old_or_obsolete_entries failure" 4171 " -- OLD or OBSOLETE method found -- class: %s", 4172 ik->signature_name())); 4173 ik->itable()->dump_itable(); 4174 } 4175 no_old_methods = false; 4176 } 4177 4178 // the constant pool cache should never contain non-deleted old or obsolete methods 4179 if (ik->constants() != NULL && 4180 ik->constants()->cache() != NULL && 4181 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) { 4182 if (RC_TRACE_ENABLED(0x00004000)) { 4183 RC_TRACE_WITH_THREAD(0x00004000, _thread, 4184 ("cp-cache::check_no_old_or_obsolete_entries failure" 4185 " -- OLD or OBSOLETE method found -- class: %s", 4186 ik->signature_name())); 4187 ik->constants()->cache()->dump_cache(); 4188 } 4189 no_old_methods = false; 4190 } 4191 } 4192 4193 // print and fail guarantee if old methods are found. 4194 if (!no_old_methods) { 4195 if (RC_TRACE_ENABLED(0x00004000)) { 4196 dump_methods(); 4197 } else { 4198 tty->print_cr("INFO: use the '-XX:TraceRedefineClasses=16384' option " 4199 "to see more info about the following guarantee() failure."); 4200 } 4201 guarantee(false, "OLD and/or OBSOLETE method(s) found"); 4202 } 4203 } 4204 4205 4206 void VM_RedefineClasses::dump_methods() { 4207 int j; 4208 RC_TRACE(0x00004000, ("_old_methods --")); 4209 for (j = 0; j < _old_methods->length(); ++j) { 4210 Method* m = _old_methods->at(j); 4211 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index())); 4212 m->access_flags().print_on(tty); 4213 tty->print(" -- "); 4214 m->print_name(tty); 4215 tty->cr(); 4216 } 4217 RC_TRACE(0x00004000, ("_new_methods --")); 4218 for (j = 0; j < _new_methods->length(); ++j) { 4219 Method* m = _new_methods->at(j); 4220 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index())); 4221 m->access_flags().print_on(tty); 4222 tty->print(" -- "); 4223 m->print_name(tty); 4224 tty->cr(); 4225 } 4226 RC_TRACE(0x00004000, ("_matching_(old/new)_methods --")); 4227 for (j = 0; j < _matching_methods_length; ++j) { 4228 Method* m = _matching_old_methods[j]; 4229 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index())); 4230 m->access_flags().print_on(tty); 4231 tty->print(" -- "); 4232 m->print_name(tty); 4233 tty->cr(); 4234 m = _matching_new_methods[j]; 4235 RC_TRACE_NO_CR(0x00004000, (" (%5d) ", m->vtable_index())); 4236 m->access_flags().print_on(tty); 4237 tty->cr(); 4238 } 4239 RC_TRACE(0x00004000, ("_deleted_methods --")); 4240 for (j = 0; j < _deleted_methods_length; ++j) { 4241 Method* m = _deleted_methods[j]; 4242 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index())); 4243 m->access_flags().print_on(tty); 4244 tty->print(" -- "); 4245 m->print_name(tty); 4246 tty->cr(); 4247 } 4248 RC_TRACE(0x00004000, ("_added_methods --")); 4249 for (j = 0; j < _added_methods_length; ++j) { 4250 Method* m = _added_methods[j]; 4251 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index())); 4252 m->access_flags().print_on(tty); 4253 tty->print(" -- "); 4254 m->print_name(tty); 4255 tty->cr(); 4256 } 4257 } 4258 4259 void VM_RedefineClasses::print_on_error(outputStream* st) const { 4260 VM_Operation::print_on_error(st); 4261 if (_the_class_oop != NULL) { 4262 ResourceMark rm; 4263 st->print_cr(", redefining class %s", _the_class_oop->external_name()); 4264 } 4265 }