1 /* 2 * Copyright (c) 2003, 2014, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "classfile/metadataOnStackMark.hpp" 27 #include "classfile/systemDictionary.hpp" 28 #include "classfile/verifier.hpp" 29 #include "code/codeCache.hpp" 30 #include "compiler/compileBroker.hpp" 31 #include "interpreter/oopMapCache.hpp" 32 #include "interpreter/rewriter.hpp" 33 #include "memory/gcLocker.hpp" 34 #include "memory/metadataFactory.hpp" 35 #include "memory/metaspaceShared.hpp" 36 #include "memory/universe.inline.hpp" 37 #include "oops/fieldStreams.hpp" 38 #include "oops/klassVtable.hpp" 39 #include "prims/jvmtiImpl.hpp" 40 #include "prims/jvmtiRedefineClasses.hpp" 41 #include "prims/methodComparator.hpp" 42 #include "runtime/deoptimization.hpp" 43 #include "runtime/relocator.hpp" 44 #include "utilities/bitMap.inline.hpp" 45 46 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC 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 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data(); 145 // Free the memory for this class at class unloading time. Not before 146 // because CMS might think this is still live. 147 cld->add_to_deallocate_list((InstanceKlass*)_scratch_classes[i]); 148 _scratch_classes[i] = NULL; 149 } 150 151 // Clean out MethodData pointing to old Method* 152 MethodDataCleaner clean_weak_method_links; 153 ClassLoaderDataGraph::classes_do(&clean_weak_method_links); 154 155 // Disable any dependent concurrent compilations 156 SystemDictionary::notice_modification(); 157 158 // Set flag indicating that some invariants are no longer true. 159 // See jvmtiExport.hpp for detailed explanation. 160 JvmtiExport::set_has_redefined_a_class(); 161 162 // check_class() is optionally called for product bits, but is 163 // always called for non-product bits. 164 #ifdef PRODUCT 165 if (RC_TRACE_ENABLED(0x00004000)) { 166 #endif 167 RC_TRACE_WITH_THREAD(0x00004000, thread, ("calling check_class")); 168 CheckClass check_class(thread); 169 ClassLoaderDataGraph::classes_do(&check_class); 170 #ifdef PRODUCT 171 } 172 #endif 173 } 174 175 void VM_RedefineClasses::doit_epilogue() { 176 // Free os::malloc allocated memory. 177 os::free(_scratch_classes); 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 idnum_owner->set_method_idnum(new_num); 785 } 786 k_new_method->set_method_idnum(old_num); 787 if (thread->has_pending_exception()) { 788 return JVMTI_ERROR_OUT_OF_MEMORY; 789 } 790 } 791 } 792 RC_TRACE(0x00008000, ("Method matched: new: %s [%d] == old: %s [%d]", 793 k_new_method->name_and_sig_as_C_string(), ni, 794 k_old_method->name_and_sig_as_C_string(), oi)); 795 // advance to next pair of methods 796 ++oi; 797 ++ni; 798 break; 799 case added: 800 // method added, see if it is OK 801 new_flags = (jushort) k_new_method->access_flags().get_flags(); 802 if ((new_flags & JVM_ACC_PRIVATE) == 0 803 // hack: private should be treated as final, but alas 804 || (new_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0 805 ) { 806 // new methods must be private 807 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED; 808 } 809 { 810 u2 num = the_class->next_method_idnum(); 811 if (num == ConstMethod::UNSET_IDNUM) { 812 // cannot add any more methods 813 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED; 814 } 815 u2 new_num = k_new_method->method_idnum(); 816 Method* idnum_owner = scratch_class->method_with_idnum(num); 817 if (idnum_owner != NULL) { 818 // There is already a method assigned this idnum -- switch them 819 idnum_owner->set_method_idnum(new_num); 820 } 821 k_new_method->set_method_idnum(num); 822 if (thread->has_pending_exception()) { 823 return JVMTI_ERROR_OUT_OF_MEMORY; 824 } 825 } 826 RC_TRACE(0x00008000, ("Method added: new: %s [%d]", 827 k_new_method->name_and_sig_as_C_string(), ni)); 828 ++ni; // advance to next new method 829 break; 830 case deleted: 831 // method deleted, see if it is OK 832 old_flags = (jushort) k_old_method->access_flags().get_flags(); 833 if ((old_flags & JVM_ACC_PRIVATE) == 0 834 // hack: private should be treated as final, but alas 835 || (old_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0 836 ) { 837 // deleted methods must be private 838 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED; 839 } 840 RC_TRACE(0x00008000, ("Method deleted: old: %s [%d]", 841 k_old_method->name_and_sig_as_C_string(), oi)); 842 ++oi; // advance to next old method 843 break; 844 default: 845 ShouldNotReachHere(); 846 } 847 } 848 849 return JVMTI_ERROR_NONE; 850 } 851 852 853 // Find new constant pool index value for old constant pool index value 854 // by seaching the index map. Returns zero (0) if there is no mapped 855 // value for the old constant pool index. 856 int VM_RedefineClasses::find_new_index(int old_index) { 857 if (_index_map_count == 0) { 858 // map is empty so nothing can be found 859 return 0; 860 } 861 862 if (old_index < 1 || old_index >= _index_map_p->length()) { 863 // The old_index is out of range so it is not mapped. This should 864 // not happen in regular constant pool merging use, but it can 865 // happen if a corrupt annotation is processed. 866 return 0; 867 } 868 869 int value = _index_map_p->at(old_index); 870 if (value == -1) { 871 // the old_index is not mapped 872 return 0; 873 } 874 875 return value; 876 } // end find_new_index() 877 878 879 // Find new bootstrap specifier index value for old bootstrap specifier index 880 // value by seaching the index map. Returns unused index (-1) if there is 881 // no mapped value for the old bootstrap specifier index. 882 int VM_RedefineClasses::find_new_operand_index(int old_index) { 883 if (_operands_index_map_count == 0) { 884 // map is empty so nothing can be found 885 return -1; 886 } 887 888 if (old_index == -1 || old_index >= _operands_index_map_p->length()) { 889 // The old_index is out of range so it is not mapped. 890 // This should not happen in regular constant pool merging use. 891 return -1; 892 } 893 894 int value = _operands_index_map_p->at(old_index); 895 if (value == -1) { 896 // the old_index is not mapped 897 return -1; 898 } 899 900 return value; 901 } // end find_new_operand_index() 902 903 904 // Returns true if the current mismatch is due to a resolved/unresolved 905 // class pair. Otherwise, returns false. 906 bool VM_RedefineClasses::is_unresolved_class_mismatch(constantPoolHandle cp1, 907 int index1, constantPoolHandle cp2, int index2) { 908 909 jbyte t1 = cp1->tag_at(index1).value(); 910 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) { 911 return false; // wrong entry type; not our special case 912 } 913 914 jbyte t2 = cp2->tag_at(index2).value(); 915 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) { 916 return false; // wrong entry type; not our special case 917 } 918 919 if (t1 == t2) { 920 return false; // not a mismatch; not our special case 921 } 922 923 char *s1 = cp1->klass_name_at(index1)->as_C_string(); 924 char *s2 = cp2->klass_name_at(index2)->as_C_string(); 925 if (strcmp(s1, s2) != 0) { 926 return false; // strings don't match; not our special case 927 } 928 929 return true; // made it through the gauntlet; this is our special case 930 } // end is_unresolved_class_mismatch() 931 932 933 jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) { 934 935 // For consistency allocate memory using os::malloc wrapper. 936 _scratch_classes = (Klass**) 937 os::malloc(sizeof(Klass*) * _class_count, mtClass); 938 if (_scratch_classes == NULL) { 939 return JVMTI_ERROR_OUT_OF_MEMORY; 940 } 941 // Zero initialize the _scratch_classes array. 942 for (int i = 0; i < _class_count; i++) { 943 _scratch_classes[i] = NULL; 944 } 945 946 ResourceMark rm(THREAD); 947 948 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current()); 949 // state can only be NULL if the current thread is exiting which 950 // should not happen since we're trying to do a RedefineClasses 951 guarantee(state != NULL, "exiting thread calling load_new_class_versions"); 952 for (int i = 0; i < _class_count; i++) { 953 // Create HandleMark so that any handles created while loading new class 954 // versions are deleted. Constant pools are deallocated while merging 955 // constant pools 956 HandleMark hm(THREAD); 957 958 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass); 959 // classes for primitives cannot be redefined 960 if (!is_modifiable_class(mirror)) { 961 return JVMTI_ERROR_UNMODIFIABLE_CLASS; 962 } 963 Klass* the_class_oop = java_lang_Class::as_Klass(mirror); 964 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop); 965 Symbol* the_class_sym = the_class->name(); 966 967 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 968 RC_TRACE_WITH_THREAD(0x00000001, THREAD, 969 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)", 970 the_class->external_name(), _class_load_kind, 971 os::available_memory() >> 10)); 972 973 ClassFileStream st((u1*) _class_defs[i].class_bytes, 974 _class_defs[i].class_byte_count, (char *)"__VM_RedefineClasses__"); 975 976 // Parse the stream. 977 Handle the_class_loader(THREAD, the_class->class_loader()); 978 Handle protection_domain(THREAD, the_class->protection_domain()); 979 // Set redefined class handle in JvmtiThreadState class. 980 // This redefined class is sent to agent event handler for class file 981 // load hook event. 982 state->set_class_being_redefined(&the_class, _class_load_kind); 983 984 Klass* k = SystemDictionary::parse_stream(the_class_sym, 985 the_class_loader, 986 protection_domain, 987 &st, 988 THREAD); 989 // Clear class_being_redefined just to be sure. 990 state->clear_class_being_redefined(); 991 992 // TODO: if this is retransform, and nothing changed we can skip it 993 994 instanceKlassHandle scratch_class (THREAD, k); 995 996 // Need to clean up allocated InstanceKlass if there's an error so assign 997 // the result here. Caller deallocates all the scratch classes in case of 998 // an error. 999 _scratch_classes[i] = k; 1000 1001 if (HAS_PENDING_EXCEPTION) { 1002 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1003 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1004 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("parse_stream exception: '%s'", 1005 ex_name->as_C_string())); 1006 CLEAR_PENDING_EXCEPTION; 1007 1008 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) { 1009 return JVMTI_ERROR_UNSUPPORTED_VERSION; 1010 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) { 1011 return JVMTI_ERROR_INVALID_CLASS_FORMAT; 1012 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) { 1013 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION; 1014 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) { 1015 // The message will be "XXX (wrong name: YYY)" 1016 return JVMTI_ERROR_NAMES_DONT_MATCH; 1017 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1018 return JVMTI_ERROR_OUT_OF_MEMORY; 1019 } else { // Just in case more exceptions can be thrown.. 1020 return JVMTI_ERROR_FAILS_VERIFICATION; 1021 } 1022 } 1023 1024 // Ensure class is linked before redefine 1025 if (!the_class->is_linked()) { 1026 the_class->link_class(THREAD); 1027 if (HAS_PENDING_EXCEPTION) { 1028 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1029 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1030 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("link_class exception: '%s'", 1031 ex_name->as_C_string())); 1032 CLEAR_PENDING_EXCEPTION; 1033 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1034 return JVMTI_ERROR_OUT_OF_MEMORY; 1035 } else { 1036 return JVMTI_ERROR_INTERNAL; 1037 } 1038 } 1039 } 1040 1041 // Do the validity checks in compare_and_normalize_class_versions() 1042 // before verifying the byte codes. By doing these checks first, we 1043 // limit the number of functions that require redirection from 1044 // the_class to scratch_class. In particular, we don't have to 1045 // modify JNI GetSuperclass() and thus won't change its performance. 1046 jvmtiError res = compare_and_normalize_class_versions(the_class, 1047 scratch_class); 1048 if (res != JVMTI_ERROR_NONE) { 1049 return res; 1050 } 1051 1052 // verify what the caller passed us 1053 { 1054 // The bug 6214132 caused the verification to fail. 1055 // Information about the_class and scratch_class is temporarily 1056 // recorded into jvmtiThreadState. This data is used to redirect 1057 // the_class to scratch_class in the JVM_* functions called by the 1058 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed 1059 // description. 1060 RedefineVerifyMark rvm(&the_class, &scratch_class, state); 1061 Verifier::verify( 1062 scratch_class, Verifier::ThrowException, true, THREAD); 1063 } 1064 1065 if (HAS_PENDING_EXCEPTION) { 1066 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1067 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1068 RC_TRACE_WITH_THREAD(0x00000002, THREAD, 1069 ("verify_byte_codes exception: '%s'", ex_name->as_C_string())); 1070 CLEAR_PENDING_EXCEPTION; 1071 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1072 return JVMTI_ERROR_OUT_OF_MEMORY; 1073 } else { 1074 // tell the caller the bytecodes are bad 1075 return JVMTI_ERROR_FAILS_VERIFICATION; 1076 } 1077 } 1078 1079 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD); 1080 if (HAS_PENDING_EXCEPTION) { 1081 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1082 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1083 RC_TRACE_WITH_THREAD(0x00000002, THREAD, 1084 ("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string())); 1085 CLEAR_PENDING_EXCEPTION; 1086 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1087 return JVMTI_ERROR_OUT_OF_MEMORY; 1088 } else { 1089 return JVMTI_ERROR_INTERNAL; 1090 } 1091 } 1092 1093 if (VerifyMergedCPBytecodes) { 1094 // verify what we have done during constant pool merging 1095 { 1096 RedefineVerifyMark rvm(&the_class, &scratch_class, state); 1097 Verifier::verify(scratch_class, Verifier::ThrowException, true, THREAD); 1098 } 1099 1100 if (HAS_PENDING_EXCEPTION) { 1101 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1102 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1103 RC_TRACE_WITH_THREAD(0x00000002, THREAD, 1104 ("verify_byte_codes post merge-CP exception: '%s'", 1105 ex_name->as_C_string())); 1106 CLEAR_PENDING_EXCEPTION; 1107 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1108 return JVMTI_ERROR_OUT_OF_MEMORY; 1109 } else { 1110 // tell the caller that constant pool merging screwed up 1111 return JVMTI_ERROR_INTERNAL; 1112 } 1113 } 1114 } 1115 1116 Rewriter::rewrite(scratch_class, THREAD); 1117 if (!HAS_PENDING_EXCEPTION) { 1118 scratch_class->link_methods(THREAD); 1119 } 1120 if (HAS_PENDING_EXCEPTION) { 1121 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1122 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1123 RC_TRACE_WITH_THREAD(0x00000002, THREAD, 1124 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string())); 1125 CLEAR_PENDING_EXCEPTION; 1126 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1127 return JVMTI_ERROR_OUT_OF_MEMORY; 1128 } else { 1129 return JVMTI_ERROR_INTERNAL; 1130 } 1131 } 1132 1133 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1134 RC_TRACE_WITH_THREAD(0x00000001, THREAD, 1135 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)", 1136 the_class->external_name(), os::available_memory() >> 10)); 1137 } 1138 1139 return JVMTI_ERROR_NONE; 1140 } 1141 1142 1143 // Map old_index to new_index as needed. scratch_cp is only needed 1144 // for RC_TRACE() calls. 1145 void VM_RedefineClasses::map_index(constantPoolHandle scratch_cp, 1146 int old_index, int new_index) { 1147 if (find_new_index(old_index) != 0) { 1148 // old_index is already mapped 1149 return; 1150 } 1151 1152 if (old_index == new_index) { 1153 // no mapping is needed 1154 return; 1155 } 1156 1157 _index_map_p->at_put(old_index, new_index); 1158 _index_map_count++; 1159 1160 RC_TRACE(0x00040000, ("mapped tag %d at index %d to %d", 1161 scratch_cp->tag_at(old_index).value(), old_index, new_index)); 1162 } // end map_index() 1163 1164 1165 // Map old_index to new_index as needed. 1166 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) { 1167 if (find_new_operand_index(old_index) != -1) { 1168 // old_index is already mapped 1169 return; 1170 } 1171 1172 if (old_index == new_index) { 1173 // no mapping is needed 1174 return; 1175 } 1176 1177 _operands_index_map_p->at_put(old_index, new_index); 1178 _operands_index_map_count++; 1179 1180 RC_TRACE(0x00040000, ("mapped bootstrap specifier at index %d to %d", old_index, new_index)); 1181 } // end map_index() 1182 1183 1184 // Merge old_cp and scratch_cp and return the results of the merge via 1185 // merge_cp_p. The number of entries in *merge_cp_p is returned via 1186 // merge_cp_length_p. The entries in old_cp occupy the same locations 1187 // in *merge_cp_p. Also creates a map of indices from entries in 1188 // scratch_cp to the corresponding entry in *merge_cp_p. Index map 1189 // entries are only created for entries in scratch_cp that occupy a 1190 // different location in *merged_cp_p. 1191 bool VM_RedefineClasses::merge_constant_pools(constantPoolHandle old_cp, 1192 constantPoolHandle scratch_cp, constantPoolHandle *merge_cp_p, 1193 int *merge_cp_length_p, TRAPS) { 1194 1195 if (merge_cp_p == NULL) { 1196 assert(false, "caller must provide scratch constantPool"); 1197 return false; // robustness 1198 } 1199 if (merge_cp_length_p == NULL) { 1200 assert(false, "caller must provide scratch CP length"); 1201 return false; // robustness 1202 } 1203 // Worst case we need old_cp->length() + scratch_cp()->length(), 1204 // but the caller might be smart so make sure we have at least 1205 // the minimum. 1206 if ((*merge_cp_p)->length() < old_cp->length()) { 1207 assert(false, "merge area too small"); 1208 return false; // robustness 1209 } 1210 1211 RC_TRACE_WITH_THREAD(0x00010000, THREAD, 1212 ("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(), 1213 scratch_cp->length())); 1214 1215 { 1216 // Pass 0: 1217 // The old_cp is copied to *merge_cp_p; this means that any code 1218 // using old_cp does not have to change. This work looks like a 1219 // perfect fit for ConstantPool*::copy_cp_to(), but we need to 1220 // handle one special case: 1221 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass 1222 // This will make verification happy. 1223 1224 int old_i; // index into old_cp 1225 1226 // index zero (0) is not used in constantPools 1227 for (old_i = 1; old_i < old_cp->length(); old_i++) { 1228 // leave debugging crumb 1229 jbyte old_tag = old_cp->tag_at(old_i).value(); 1230 switch (old_tag) { 1231 case JVM_CONSTANT_Class: 1232 case JVM_CONSTANT_UnresolvedClass: 1233 // revert the copy to JVM_CONSTANT_UnresolvedClass 1234 // May be resolving while calling this so do the same for 1235 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition) 1236 (*merge_cp_p)->unresolved_klass_at_put(old_i, 1237 old_cp->klass_name_at(old_i)); 1238 break; 1239 1240 case JVM_CONSTANT_Double: 1241 case JVM_CONSTANT_Long: 1242 // just copy the entry to *merge_cp_p, but double and long take 1243 // two constant pool entries 1244 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0); 1245 old_i++; 1246 break; 1247 1248 default: 1249 // just copy the entry to *merge_cp_p 1250 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0); 1251 break; 1252 } 1253 } // end for each old_cp entry 1254 1255 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_0); 1256 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_0); 1257 1258 // We don't need to sanity check that *merge_cp_length_p is within 1259 // *merge_cp_p bounds since we have the minimum on-entry check above. 1260 (*merge_cp_length_p) = old_i; 1261 } 1262 1263 // merge_cp_len should be the same as old_cp->length() at this point 1264 // so this trace message is really a "warm-and-breathing" message. 1265 RC_TRACE_WITH_THREAD(0x00020000, THREAD, 1266 ("after pass 0: merge_cp_len=%d", *merge_cp_length_p)); 1267 1268 int scratch_i; // index into scratch_cp 1269 { 1270 // Pass 1a: 1271 // Compare scratch_cp entries to the old_cp entries that we have 1272 // already copied to *merge_cp_p. In this pass, we are eliminating 1273 // exact duplicates (matching entry at same index) so we only 1274 // compare entries in the common indice range. 1275 int increment = 1; 1276 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length()); 1277 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) { 1278 switch (scratch_cp->tag_at(scratch_i).value()) { 1279 case JVM_CONSTANT_Double: 1280 case JVM_CONSTANT_Long: 1281 // double and long take two constant pool entries 1282 increment = 2; 1283 break; 1284 1285 default: 1286 increment = 1; 1287 break; 1288 } 1289 1290 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p, 1291 scratch_i, CHECK_0); 1292 if (match) { 1293 // found a match at the same index so nothing more to do 1294 continue; 1295 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i, 1296 *merge_cp_p, scratch_i)) { 1297 // The mismatch in compare_entry_to() above is because of a 1298 // resolved versus unresolved class entry at the same index 1299 // with the same string value. Since Pass 0 reverted any 1300 // class entries to unresolved class entries in *merge_cp_p, 1301 // we go with the unresolved class entry. 1302 continue; 1303 } 1304 1305 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, 1306 CHECK_0); 1307 if (found_i != 0) { 1308 guarantee(found_i != scratch_i, 1309 "compare_entry_to() and find_matching_entry() do not agree"); 1310 1311 // Found a matching entry somewhere else in *merge_cp_p so 1312 // just need a mapping entry. 1313 map_index(scratch_cp, scratch_i, found_i); 1314 continue; 1315 } 1316 1317 // The find_matching_entry() call above could fail to find a match 1318 // due to a resolved versus unresolved class or string entry situation 1319 // like we solved above with the is_unresolved_*_mismatch() calls. 1320 // However, we would have to call is_unresolved_*_mismatch() over 1321 // all of *merge_cp_p (potentially) and that doesn't seem to be 1322 // worth the time. 1323 1324 // No match found so we have to append this entry and any unique 1325 // referenced entries to *merge_cp_p. 1326 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p, 1327 CHECK_0); 1328 } 1329 } 1330 1331 RC_TRACE_WITH_THREAD(0x00020000, THREAD, 1332 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", 1333 *merge_cp_length_p, scratch_i, _index_map_count)); 1334 1335 if (scratch_i < scratch_cp->length()) { 1336 // Pass 1b: 1337 // old_cp is smaller than scratch_cp so there are entries in 1338 // scratch_cp that we have not yet processed. We take care of 1339 // those now. 1340 int increment = 1; 1341 for (; scratch_i < scratch_cp->length(); scratch_i += increment) { 1342 switch (scratch_cp->tag_at(scratch_i).value()) { 1343 case JVM_CONSTANT_Double: 1344 case JVM_CONSTANT_Long: 1345 // double and long take two constant pool entries 1346 increment = 2; 1347 break; 1348 1349 default: 1350 increment = 1; 1351 break; 1352 } 1353 1354 int found_i = 1355 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0); 1356 if (found_i != 0) { 1357 // Found a matching entry somewhere else in *merge_cp_p so 1358 // just need a mapping entry. 1359 map_index(scratch_cp, scratch_i, found_i); 1360 continue; 1361 } 1362 1363 // No match found so we have to append this entry and any unique 1364 // referenced entries to *merge_cp_p. 1365 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p, 1366 CHECK_0); 1367 } 1368 1369 RC_TRACE_WITH_THREAD(0x00020000, THREAD, 1370 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", 1371 *merge_cp_length_p, scratch_i, _index_map_count)); 1372 } 1373 finalize_operands_merge(*merge_cp_p, THREAD); 1374 1375 return true; 1376 } // end merge_constant_pools() 1377 1378 1379 // Scoped object to clean up the constant pool(s) created for merging 1380 class MergeCPCleaner { 1381 ClassLoaderData* _loader_data; 1382 ConstantPool* _cp; 1383 ConstantPool* _scratch_cp; 1384 public: 1385 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) : 1386 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {} 1387 ~MergeCPCleaner() { 1388 _loader_data->add_to_deallocate_list(_cp); 1389 if (_scratch_cp != NULL) { 1390 _loader_data->add_to_deallocate_list(_scratch_cp); 1391 } 1392 } 1393 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; } 1394 }; 1395 1396 // Merge constant pools between the_class and scratch_class and 1397 // potentially rewrite bytecodes in scratch_class to use the merged 1398 // constant pool. 1399 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite( 1400 instanceKlassHandle the_class, instanceKlassHandle scratch_class, 1401 TRAPS) { 1402 // worst case merged constant pool length is old and new combined 1403 int merge_cp_length = the_class->constants()->length() 1404 + scratch_class->constants()->length(); 1405 1406 // Constant pools are not easily reused so we allocate a new one 1407 // each time. 1408 // merge_cp is created unsafe for concurrent GC processing. It 1409 // should be marked safe before discarding it. Even though 1410 // garbage, if it crosses a card boundary, it may be scanned 1411 // in order to find the start of the first complete object on the card. 1412 ClassLoaderData* loader_data = the_class->class_loader_data(); 1413 ConstantPool* merge_cp_oop = 1414 ConstantPool::allocate(loader_data, 1415 merge_cp_length, 1416 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1417 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop); 1418 1419 HandleMark hm(THREAD); // make sure handles are cleared before 1420 // MergeCPCleaner clears out merge_cp_oop 1421 constantPoolHandle merge_cp(THREAD, merge_cp_oop); 1422 1423 // Get constants() from the old class because it could have been rewritten 1424 // while we were at a safepoint allocating a new constant pool. 1425 constantPoolHandle old_cp(THREAD, the_class->constants()); 1426 constantPoolHandle scratch_cp(THREAD, scratch_class->constants()); 1427 1428 // If the length changed, the class was redefined out from under us. Return 1429 // an error. 1430 if (merge_cp_length != the_class->constants()->length() 1431 + scratch_class->constants()->length()) { 1432 return JVMTI_ERROR_INTERNAL; 1433 } 1434 1435 // Update the version number of the constant pool 1436 merge_cp->increment_and_save_version(old_cp->version()); 1437 1438 ResourceMark rm(THREAD); 1439 _index_map_count = 0; 1440 _index_map_p = new intArray(scratch_cp->length(), -1); 1441 1442 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands()); 1443 _operands_index_map_count = 0; 1444 _operands_index_map_p = new intArray( 1445 ConstantPool::operand_array_length(scratch_cp->operands()), -1); 1446 1447 // reference to the cp holder is needed for copy_operands() 1448 merge_cp->set_pool_holder(scratch_class()); 1449 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp, 1450 &merge_cp_length, THREAD); 1451 merge_cp->set_pool_holder(NULL); 1452 1453 if (!result) { 1454 // The merge can fail due to memory allocation failure or due 1455 // to robustness checks. 1456 return JVMTI_ERROR_INTERNAL; 1457 } 1458 1459 RC_TRACE_WITH_THREAD(0x00010000, THREAD, 1460 ("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count)); 1461 1462 if (_index_map_count == 0) { 1463 // there is nothing to map between the new and merged constant pools 1464 1465 if (old_cp->length() == scratch_cp->length()) { 1466 // The old and new constant pools are the same length and the 1467 // index map is empty. This means that the three constant pools 1468 // are equivalent (but not the same). Unfortunately, the new 1469 // constant pool has not gone through link resolution nor have 1470 // the new class bytecodes gone through constant pool cache 1471 // rewriting so we can't use the old constant pool with the new 1472 // class. 1473 1474 // toss the merged constant pool at return 1475 } else if (old_cp->length() < scratch_cp->length()) { 1476 // The old constant pool has fewer entries than the new constant 1477 // pool and the index map is empty. This means the new constant 1478 // pool is a superset of the old constant pool. However, the old 1479 // class bytecodes have already gone through constant pool cache 1480 // rewriting so we can't use the new constant pool with the old 1481 // class. 1482 1483 // toss the merged constant pool at return 1484 } else { 1485 // The old constant pool has more entries than the new constant 1486 // pool and the index map is empty. This means that both the old 1487 // and merged constant pools are supersets of the new constant 1488 // pool. 1489 1490 // Replace the new constant pool with a shrunken copy of the 1491 // merged constant pool 1492 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, 1493 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1494 // The new constant pool replaces scratch_cp so have cleaner clean it up. 1495 // It can't be cleaned up while there are handles to it. 1496 cp_cleaner.add_scratch_cp(scratch_cp()); 1497 } 1498 } else { 1499 if (RC_TRACE_ENABLED(0x00040000)) { 1500 // don't want to loop unless we are tracing 1501 int count = 0; 1502 for (int i = 1; i < _index_map_p->length(); i++) { 1503 int value = _index_map_p->at(i); 1504 1505 if (value != -1) { 1506 RC_TRACE_WITH_THREAD(0x00040000, THREAD, 1507 ("index_map[%d]: old=%d new=%d", count, i, value)); 1508 count++; 1509 } 1510 } 1511 } 1512 1513 // We have entries mapped between the new and merged constant pools 1514 // so we have to rewrite some constant pool references. 1515 if (!rewrite_cp_refs(scratch_class, THREAD)) { 1516 return JVMTI_ERROR_INTERNAL; 1517 } 1518 1519 // Replace the new constant pool with a shrunken copy of the 1520 // merged constant pool so now the rewritten bytecodes have 1521 // valid references; the previous new constant pool will get 1522 // GCed. 1523 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, 1524 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1525 // The new constant pool replaces scratch_cp so have cleaner clean it up. 1526 // It can't be cleaned up while there are handles to it. 1527 cp_cleaner.add_scratch_cp(scratch_cp()); 1528 } 1529 1530 return JVMTI_ERROR_NONE; 1531 } // end merge_cp_and_rewrite() 1532 1533 1534 // Rewrite constant pool references in klass scratch_class. 1535 bool VM_RedefineClasses::rewrite_cp_refs(instanceKlassHandle scratch_class, 1536 TRAPS) { 1537 1538 // rewrite constant pool references in the methods: 1539 if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) { 1540 // propagate failure back to caller 1541 return false; 1542 } 1543 1544 // rewrite constant pool references in the class_annotations: 1545 if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) { 1546 // propagate failure back to caller 1547 return false; 1548 } 1549 1550 // rewrite constant pool references in the fields_annotations: 1551 if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) { 1552 // propagate failure back to caller 1553 return false; 1554 } 1555 1556 // rewrite constant pool references in the methods_annotations: 1557 if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) { 1558 // propagate failure back to caller 1559 return false; 1560 } 1561 1562 // rewrite constant pool references in the methods_parameter_annotations: 1563 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class, 1564 THREAD)) { 1565 // propagate failure back to caller 1566 return false; 1567 } 1568 1569 // rewrite constant pool references in the methods_default_annotations: 1570 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class, 1571 THREAD)) { 1572 // propagate failure back to caller 1573 return false; 1574 } 1575 1576 // rewrite constant pool references in the class_type_annotations: 1577 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class, THREAD)) { 1578 // propagate failure back to caller 1579 return false; 1580 } 1581 1582 // rewrite constant pool references in the fields_type_annotations: 1583 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class, THREAD)) { 1584 // propagate failure back to caller 1585 return false; 1586 } 1587 1588 // rewrite constant pool references in the methods_type_annotations: 1589 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class, THREAD)) { 1590 // propagate failure back to caller 1591 return false; 1592 } 1593 1594 // There can be type annotations in the Code part of a method_info attribute. 1595 // These annotations are not accessible, even by reflection. 1596 // Currently they are not even parsed by the ClassFileParser. 1597 // If runtime access is added they will also need to be rewritten. 1598 1599 // rewrite source file name index: 1600 u2 source_file_name_idx = scratch_class->source_file_name_index(); 1601 if (source_file_name_idx != 0) { 1602 u2 new_source_file_name_idx = find_new_index(source_file_name_idx); 1603 if (new_source_file_name_idx != 0) { 1604 scratch_class->set_source_file_name_index(new_source_file_name_idx); 1605 } 1606 } 1607 1608 // rewrite class generic signature index: 1609 u2 generic_signature_index = scratch_class->generic_signature_index(); 1610 if (generic_signature_index != 0) { 1611 u2 new_generic_signature_index = find_new_index(generic_signature_index); 1612 if (new_generic_signature_index != 0) { 1613 scratch_class->set_generic_signature_index(new_generic_signature_index); 1614 } 1615 } 1616 1617 return true; 1618 } // end rewrite_cp_refs() 1619 1620 // Rewrite constant pool references in the methods. 1621 bool VM_RedefineClasses::rewrite_cp_refs_in_methods( 1622 instanceKlassHandle scratch_class, TRAPS) { 1623 1624 Array<Method*>* methods = scratch_class->methods(); 1625 1626 if (methods == NULL || methods->length() == 0) { 1627 // no methods so nothing to do 1628 return true; 1629 } 1630 1631 // rewrite constant pool references in the methods: 1632 for (int i = methods->length() - 1; i >= 0; i--) { 1633 methodHandle method(THREAD, methods->at(i)); 1634 methodHandle new_method; 1635 rewrite_cp_refs_in_method(method, &new_method, THREAD); 1636 if (!new_method.is_null()) { 1637 // the method has been replaced so save the new method version 1638 // even in the case of an exception. original method is on the 1639 // deallocation list. 1640 methods->at_put(i, new_method()); 1641 } 1642 if (HAS_PENDING_EXCEPTION) { 1643 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1644 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1645 RC_TRACE_WITH_THREAD(0x00000002, THREAD, 1646 ("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string())); 1647 // Need to clear pending exception here as the super caller sets 1648 // the JVMTI_ERROR_INTERNAL if the returned value is false. 1649 CLEAR_PENDING_EXCEPTION; 1650 return false; 1651 } 1652 } 1653 1654 return true; 1655 } 1656 1657 1658 // Rewrite constant pool references in the specific method. This code 1659 // was adapted from Rewriter::rewrite_method(). 1660 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method, 1661 methodHandle *new_method_p, TRAPS) { 1662 1663 *new_method_p = methodHandle(); // default is no new method 1664 1665 // We cache a pointer to the bytecodes here in code_base. If GC 1666 // moves the Method*, then the bytecodes will also move which 1667 // will likely cause a crash. We create a No_Safepoint_Verifier 1668 // object to detect whether we pass a possible safepoint in this 1669 // code block. 1670 No_Safepoint_Verifier nsv; 1671 1672 // Bytecodes and their length 1673 address code_base = method->code_base(); 1674 int code_length = method->code_size(); 1675 1676 int bc_length; 1677 for (int bci = 0; bci < code_length; bci += bc_length) { 1678 address bcp = code_base + bci; 1679 Bytecodes::Code c = (Bytecodes::Code)(*bcp); 1680 1681 bc_length = Bytecodes::length_for(c); 1682 if (bc_length == 0) { 1683 // More complicated bytecodes report a length of zero so 1684 // we have to try again a slightly different way. 1685 bc_length = Bytecodes::length_at(method(), bcp); 1686 } 1687 1688 assert(bc_length != 0, "impossible bytecode length"); 1689 1690 switch (c) { 1691 case Bytecodes::_ldc: 1692 { 1693 int cp_index = *(bcp + 1); 1694 int new_index = find_new_index(cp_index); 1695 1696 if (StressLdcRewrite && new_index == 0) { 1697 // If we are stressing ldc -> ldc_w rewriting, then we 1698 // always need a new_index value. 1699 new_index = cp_index; 1700 } 1701 if (new_index != 0) { 1702 // the original index is mapped so we have more work to do 1703 if (!StressLdcRewrite && new_index <= max_jubyte) { 1704 // The new value can still use ldc instead of ldc_w 1705 // unless we are trying to stress ldc -> ldc_w rewriting 1706 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 1707 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), 1708 bcp, cp_index, new_index)); 1709 *(bcp + 1) = new_index; 1710 } else { 1711 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 1712 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d", 1713 Bytecodes::name(c), bcp, cp_index, new_index)); 1714 // the new value needs ldc_w instead of ldc 1715 u_char inst_buffer[4]; // max instruction size is 4 bytes 1716 bcp = (address)inst_buffer; 1717 // construct new instruction sequence 1718 *bcp = Bytecodes::_ldc_w; 1719 bcp++; 1720 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w. 1721 // See comment below for difference between put_Java_u2() 1722 // and put_native_u2(). 1723 Bytes::put_Java_u2(bcp, new_index); 1724 1725 Relocator rc(method, NULL /* no RelocatorListener needed */); 1726 methodHandle m; 1727 { 1728 Pause_No_Safepoint_Verifier pnsv(&nsv); 1729 1730 // ldc is 2 bytes and ldc_w is 3 bytes 1731 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK); 1732 } 1733 1734 // return the new method so that the caller can update 1735 // the containing class 1736 *new_method_p = method = m; 1737 // switch our bytecode processing loop from the old method 1738 // to the new method 1739 code_base = method->code_base(); 1740 code_length = method->code_size(); 1741 bcp = code_base + bci; 1742 c = (Bytecodes::Code)(*bcp); 1743 bc_length = Bytecodes::length_for(c); 1744 assert(bc_length != 0, "sanity check"); 1745 } // end we need ldc_w instead of ldc 1746 } // end if there is a mapped index 1747 } break; 1748 1749 // these bytecodes have a two-byte constant pool index 1750 case Bytecodes::_anewarray : // fall through 1751 case Bytecodes::_checkcast : // fall through 1752 case Bytecodes::_getfield : // fall through 1753 case Bytecodes::_getstatic : // fall through 1754 case Bytecodes::_instanceof : // fall through 1755 case Bytecodes::_invokedynamic : // fall through 1756 case Bytecodes::_invokeinterface: // fall through 1757 case Bytecodes::_invokespecial : // fall through 1758 case Bytecodes::_invokestatic : // fall through 1759 case Bytecodes::_invokevirtual : // fall through 1760 case Bytecodes::_ldc_w : // fall through 1761 case Bytecodes::_ldc2_w : // fall through 1762 case Bytecodes::_multianewarray : // fall through 1763 case Bytecodes::_new : // fall through 1764 case Bytecodes::_putfield : // fall through 1765 case Bytecodes::_putstatic : 1766 { 1767 address p = bcp + 1; 1768 int cp_index = Bytes::get_Java_u2(p); 1769 int new_index = find_new_index(cp_index); 1770 if (new_index != 0) { 1771 // the original index is mapped so update w/ new value 1772 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 1773 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), 1774 bcp, cp_index, new_index)); 1775 // Rewriter::rewrite_method() uses put_native_u2() in this 1776 // situation because it is reusing the constant pool index 1777 // location for a native index into the ConstantPoolCache. 1778 // Since we are updating the constant pool index prior to 1779 // verification and ConstantPoolCache initialization, we 1780 // need to keep the new index in Java byte order. 1781 Bytes::put_Java_u2(p, new_index); 1782 } 1783 } break; 1784 } 1785 } // end for each bytecode 1786 1787 // We also need to rewrite the parameter name indexes, if there is 1788 // method parameter data present 1789 if(method->has_method_parameters()) { 1790 const int len = method->method_parameters_length(); 1791 MethodParametersElement* elem = method->method_parameters_start(); 1792 1793 for (int i = 0; i < len; i++) { 1794 const u2 cp_index = elem[i].name_cp_index; 1795 const u2 new_cp_index = find_new_index(cp_index); 1796 if (new_cp_index != 0) { 1797 elem[i].name_cp_index = new_cp_index; 1798 } 1799 } 1800 } 1801 } // end rewrite_cp_refs_in_method() 1802 1803 1804 // Rewrite constant pool references in the class_annotations field. 1805 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations( 1806 instanceKlassHandle scratch_class, TRAPS) { 1807 1808 AnnotationArray* class_annotations = scratch_class->class_annotations(); 1809 if (class_annotations == NULL || class_annotations->length() == 0) { 1810 // no class_annotations so nothing to do 1811 return true; 1812 } 1813 1814 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1815 ("class_annotations length=%d", class_annotations->length())); 1816 1817 int byte_i = 0; // byte index into class_annotations 1818 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i, 1819 THREAD); 1820 } 1821 1822 1823 // Rewrite constant pool references in an annotations typeArray. This 1824 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute 1825 // that is described in section 4.8.15 of the 2nd-edition of the VM spec: 1826 // 1827 // annotations_typeArray { 1828 // u2 num_annotations; 1829 // annotation annotations[num_annotations]; 1830 // } 1831 // 1832 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray( 1833 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) { 1834 1835 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 1836 // not enough room for num_annotations field 1837 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1838 ("length() is too small for num_annotations field")); 1839 return false; 1840 } 1841 1842 u2 num_annotations = Bytes::get_Java_u2((address) 1843 annotations_typeArray->adr_at(byte_i_ref)); 1844 byte_i_ref += 2; 1845 1846 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1847 ("num_annotations=%d", num_annotations)); 1848 1849 int calc_num_annotations = 0; 1850 for (; calc_num_annotations < num_annotations; calc_num_annotations++) { 1851 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, 1852 byte_i_ref, THREAD)) { 1853 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1854 ("bad annotation_struct at %d", calc_num_annotations)); 1855 // propagate failure back to caller 1856 return false; 1857 } 1858 } 1859 assert(num_annotations == calc_num_annotations, "sanity check"); 1860 1861 return true; 1862 } // end rewrite_cp_refs_in_annotations_typeArray() 1863 1864 1865 // Rewrite constant pool references in the annotation struct portion of 1866 // an annotations_typeArray. This "structure" is from section 4.8.15 of 1867 // the 2nd-edition of the VM spec: 1868 // 1869 // struct annotation { 1870 // u2 type_index; 1871 // u2 num_element_value_pairs; 1872 // { 1873 // u2 element_name_index; 1874 // element_value value; 1875 // } element_value_pairs[num_element_value_pairs]; 1876 // } 1877 // 1878 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct( 1879 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) { 1880 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) { 1881 // not enough room for smallest annotation_struct 1882 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1883 ("length() is too small for annotation_struct")); 1884 return false; 1885 } 1886 1887 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray, 1888 byte_i_ref, "mapped old type_index=%d", THREAD); 1889 1890 u2 num_element_value_pairs = Bytes::get_Java_u2((address) 1891 annotations_typeArray->adr_at(byte_i_ref)); 1892 byte_i_ref += 2; 1893 1894 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1895 ("type_index=%d num_element_value_pairs=%d", type_index, 1896 num_element_value_pairs)); 1897 1898 int calc_num_element_value_pairs = 0; 1899 for (; calc_num_element_value_pairs < num_element_value_pairs; 1900 calc_num_element_value_pairs++) { 1901 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 1902 // not enough room for another element_name_index, let alone 1903 // the rest of another component 1904 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1905 ("length() is too small for element_name_index")); 1906 return false; 1907 } 1908 1909 u2 element_name_index = rewrite_cp_ref_in_annotation_data( 1910 annotations_typeArray, byte_i_ref, 1911 "mapped old element_name_index=%d", THREAD); 1912 1913 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1914 ("element_name_index=%d", element_name_index)); 1915 1916 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, 1917 byte_i_ref, THREAD)) { 1918 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1919 ("bad element_value at %d", calc_num_element_value_pairs)); 1920 // propagate failure back to caller 1921 return false; 1922 } 1923 } // end for each component 1924 assert(num_element_value_pairs == calc_num_element_value_pairs, 1925 "sanity check"); 1926 1927 return true; 1928 } // end rewrite_cp_refs_in_annotation_struct() 1929 1930 1931 // Rewrite a constant pool reference at the current position in 1932 // annotations_typeArray if needed. Returns the original constant 1933 // pool reference if a rewrite was not needed or the new constant 1934 // pool reference if a rewrite was needed. 1935 PRAGMA_DIAG_PUSH 1936 PRAGMA_FORMAT_NONLITERAL_IGNORED 1937 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data( 1938 AnnotationArray* annotations_typeArray, int &byte_i_ref, 1939 const char * trace_mesg, TRAPS) { 1940 1941 address cp_index_addr = (address) 1942 annotations_typeArray->adr_at(byte_i_ref); 1943 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr); 1944 u2 new_cp_index = find_new_index(old_cp_index); 1945 if (new_cp_index != 0) { 1946 RC_TRACE_WITH_THREAD(0x02000000, THREAD, (trace_mesg, old_cp_index)); 1947 Bytes::put_Java_u2(cp_index_addr, new_cp_index); 1948 old_cp_index = new_cp_index; 1949 } 1950 byte_i_ref += 2; 1951 return old_cp_index; 1952 } 1953 PRAGMA_DIAG_POP 1954 1955 1956 // Rewrite constant pool references in the element_value portion of an 1957 // annotations_typeArray. This "structure" is from section 4.8.15.1 of 1958 // the 2nd-edition of the VM spec: 1959 // 1960 // struct element_value { 1961 // u1 tag; 1962 // union { 1963 // u2 const_value_index; 1964 // { 1965 // u2 type_name_index; 1966 // u2 const_name_index; 1967 // } enum_const_value; 1968 // u2 class_info_index; 1969 // annotation annotation_value; 1970 // struct { 1971 // u2 num_values; 1972 // element_value values[num_values]; 1973 // } array_value; 1974 // } value; 1975 // } 1976 // 1977 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value( 1978 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) { 1979 1980 if ((byte_i_ref + 1) > annotations_typeArray->length()) { 1981 // not enough room for a tag let alone the rest of an element_value 1982 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1983 ("length() is too small for a tag")); 1984 return false; 1985 } 1986 1987 u1 tag = annotations_typeArray->at(byte_i_ref); 1988 byte_i_ref++; 1989 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("tag='%c'", tag)); 1990 1991 switch (tag) { 1992 // These BaseType tag values are from Table 4.2 in VM spec: 1993 case 'B': // byte 1994 case 'C': // char 1995 case 'D': // double 1996 case 'F': // float 1997 case 'I': // int 1998 case 'J': // long 1999 case 'S': // short 2000 case 'Z': // boolean 2001 2002 // The remaining tag values are from Table 4.8 in the 2nd-edition of 2003 // the VM spec: 2004 case 's': 2005 { 2006 // For the above tag values (including the BaseType values), 2007 // value.const_value_index is right union field. 2008 2009 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2010 // not enough room for a const_value_index 2011 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2012 ("length() is too small for a const_value_index")); 2013 return false; 2014 } 2015 2016 u2 const_value_index = rewrite_cp_ref_in_annotation_data( 2017 annotations_typeArray, byte_i_ref, 2018 "mapped old const_value_index=%d", THREAD); 2019 2020 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2021 ("const_value_index=%d", const_value_index)); 2022 } break; 2023 2024 case 'e': 2025 { 2026 // for the above tag value, value.enum_const_value is right union field 2027 2028 if ((byte_i_ref + 4) > annotations_typeArray->length()) { 2029 // not enough room for a enum_const_value 2030 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2031 ("length() is too small for a enum_const_value")); 2032 return false; 2033 } 2034 2035 u2 type_name_index = rewrite_cp_ref_in_annotation_data( 2036 annotations_typeArray, byte_i_ref, 2037 "mapped old type_name_index=%d", THREAD); 2038 2039 u2 const_name_index = rewrite_cp_ref_in_annotation_data( 2040 annotations_typeArray, byte_i_ref, 2041 "mapped old const_name_index=%d", THREAD); 2042 2043 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2044 ("type_name_index=%d const_name_index=%d", type_name_index, 2045 const_name_index)); 2046 } break; 2047 2048 case 'c': 2049 { 2050 // for the above tag value, value.class_info_index is right union field 2051 2052 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2053 // not enough room for a class_info_index 2054 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2055 ("length() is too small for a class_info_index")); 2056 return false; 2057 } 2058 2059 u2 class_info_index = rewrite_cp_ref_in_annotation_data( 2060 annotations_typeArray, byte_i_ref, 2061 "mapped old class_info_index=%d", THREAD); 2062 2063 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2064 ("class_info_index=%d", class_info_index)); 2065 } break; 2066 2067 case '@': 2068 // For the above tag value, value.attr_value is the right union 2069 // field. This is a nested annotation. 2070 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, 2071 byte_i_ref, THREAD)) { 2072 // propagate failure back to caller 2073 return false; 2074 } 2075 break; 2076 2077 case '[': 2078 { 2079 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2080 // not enough room for a num_values field 2081 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2082 ("length() is too small for a num_values field")); 2083 return false; 2084 } 2085 2086 // For the above tag value, value.array_value is the right union 2087 // field. This is an array of nested element_value. 2088 u2 num_values = Bytes::get_Java_u2((address) 2089 annotations_typeArray->adr_at(byte_i_ref)); 2090 byte_i_ref += 2; 2091 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("num_values=%d", num_values)); 2092 2093 int calc_num_values = 0; 2094 for (; calc_num_values < num_values; calc_num_values++) { 2095 if (!rewrite_cp_refs_in_element_value( 2096 annotations_typeArray, byte_i_ref, THREAD)) { 2097 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2098 ("bad nested element_value at %d", calc_num_values)); 2099 // propagate failure back to caller 2100 return false; 2101 } 2102 } 2103 assert(num_values == calc_num_values, "sanity check"); 2104 } break; 2105 2106 default: 2107 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("bad tag=0x%x", tag)); 2108 return false; 2109 } // end decode tag field 2110 2111 return true; 2112 } // end rewrite_cp_refs_in_element_value() 2113 2114 2115 // Rewrite constant pool references in a fields_annotations field. 2116 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations( 2117 instanceKlassHandle scratch_class, TRAPS) { 2118 2119 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations(); 2120 2121 if (fields_annotations == NULL || fields_annotations->length() == 0) { 2122 // no fields_annotations so nothing to do 2123 return true; 2124 } 2125 2126 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2127 ("fields_annotations length=%d", fields_annotations->length())); 2128 2129 for (int i = 0; i < fields_annotations->length(); i++) { 2130 AnnotationArray* field_annotations = fields_annotations->at(i); 2131 if (field_annotations == NULL || field_annotations->length() == 0) { 2132 // this field does not have any annotations so skip it 2133 continue; 2134 } 2135 2136 int byte_i = 0; // byte index into field_annotations 2137 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i, 2138 THREAD)) { 2139 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2140 ("bad field_annotations at %d", i)); 2141 // propagate failure back to caller 2142 return false; 2143 } 2144 } 2145 2146 return true; 2147 } // end rewrite_cp_refs_in_fields_annotations() 2148 2149 2150 // Rewrite constant pool references in a methods_annotations field. 2151 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations( 2152 instanceKlassHandle scratch_class, TRAPS) { 2153 2154 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2155 Method* m = scratch_class->methods()->at(i); 2156 AnnotationArray* method_annotations = m->constMethod()->method_annotations(); 2157 2158 if (method_annotations == NULL || method_annotations->length() == 0) { 2159 // this method does not have any annotations so skip it 2160 continue; 2161 } 2162 2163 int byte_i = 0; // byte index into method_annotations 2164 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i, 2165 THREAD)) { 2166 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2167 ("bad method_annotations at %d", i)); 2168 // propagate failure back to caller 2169 return false; 2170 } 2171 } 2172 2173 return true; 2174 } // end rewrite_cp_refs_in_methods_annotations() 2175 2176 2177 // Rewrite constant pool references in a methods_parameter_annotations 2178 // field. This "structure" is adapted from the 2179 // RuntimeVisibleParameterAnnotations_attribute described in section 2180 // 4.8.17 of the 2nd-edition of the VM spec: 2181 // 2182 // methods_parameter_annotations_typeArray { 2183 // u1 num_parameters; 2184 // { 2185 // u2 num_annotations; 2186 // annotation annotations[num_annotations]; 2187 // } parameter_annotations[num_parameters]; 2188 // } 2189 // 2190 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations( 2191 instanceKlassHandle scratch_class, TRAPS) { 2192 2193 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2194 Method* m = scratch_class->methods()->at(i); 2195 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations(); 2196 if (method_parameter_annotations == NULL 2197 || method_parameter_annotations->length() == 0) { 2198 // this method does not have any parameter annotations so skip it 2199 continue; 2200 } 2201 2202 if (method_parameter_annotations->length() < 1) { 2203 // not enough room for a num_parameters field 2204 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2205 ("length() is too small for a num_parameters field at %d", i)); 2206 return false; 2207 } 2208 2209 int byte_i = 0; // byte index into method_parameter_annotations 2210 2211 u1 num_parameters = method_parameter_annotations->at(byte_i); 2212 byte_i++; 2213 2214 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2215 ("num_parameters=%d", num_parameters)); 2216 2217 int calc_num_parameters = 0; 2218 for (; calc_num_parameters < num_parameters; calc_num_parameters++) { 2219 if (!rewrite_cp_refs_in_annotations_typeArray( 2220 method_parameter_annotations, byte_i, THREAD)) { 2221 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2222 ("bad method_parameter_annotations at %d", calc_num_parameters)); 2223 // propagate failure back to caller 2224 return false; 2225 } 2226 } 2227 assert(num_parameters == calc_num_parameters, "sanity check"); 2228 } 2229 2230 return true; 2231 } // end rewrite_cp_refs_in_methods_parameter_annotations() 2232 2233 2234 // Rewrite constant pool references in a methods_default_annotations 2235 // field. This "structure" is adapted from the AnnotationDefault_attribute 2236 // that is described in section 4.8.19 of the 2nd-edition of the VM spec: 2237 // 2238 // methods_default_annotations_typeArray { 2239 // element_value default_value; 2240 // } 2241 // 2242 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations( 2243 instanceKlassHandle scratch_class, TRAPS) { 2244 2245 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2246 Method* m = scratch_class->methods()->at(i); 2247 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations(); 2248 if (method_default_annotations == NULL 2249 || method_default_annotations->length() == 0) { 2250 // this method does not have any default annotations so skip it 2251 continue; 2252 } 2253 2254 int byte_i = 0; // byte index into method_default_annotations 2255 2256 if (!rewrite_cp_refs_in_element_value( 2257 method_default_annotations, byte_i, THREAD)) { 2258 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2259 ("bad default element_value at %d", i)); 2260 // propagate failure back to caller 2261 return false; 2262 } 2263 } 2264 2265 return true; 2266 } // end rewrite_cp_refs_in_methods_default_annotations() 2267 2268 2269 // Rewrite constant pool references in a class_type_annotations field. 2270 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations( 2271 instanceKlassHandle scratch_class, TRAPS) { 2272 2273 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations(); 2274 if (class_type_annotations == NULL || class_type_annotations->length() == 0) { 2275 // no class_type_annotations so nothing to do 2276 return true; 2277 } 2278 2279 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2280 ("class_type_annotations length=%d", class_type_annotations->length())); 2281 2282 int byte_i = 0; // byte index into class_type_annotations 2283 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations, 2284 byte_i, "ClassFile", THREAD); 2285 } // end rewrite_cp_refs_in_class_type_annotations() 2286 2287 2288 // Rewrite constant pool references in a fields_type_annotations field. 2289 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations( 2290 instanceKlassHandle scratch_class, TRAPS) { 2291 2292 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations(); 2293 if (fields_type_annotations == NULL || fields_type_annotations->length() == 0) { 2294 // no fields_type_annotations so nothing to do 2295 return true; 2296 } 2297 2298 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2299 ("fields_type_annotations length=%d", fields_type_annotations->length())); 2300 2301 for (int i = 0; i < fields_type_annotations->length(); i++) { 2302 AnnotationArray* field_type_annotations = fields_type_annotations->at(i); 2303 if (field_type_annotations == NULL || field_type_annotations->length() == 0) { 2304 // this field does not have any annotations so skip it 2305 continue; 2306 } 2307 2308 int byte_i = 0; // byte index into field_type_annotations 2309 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations, 2310 byte_i, "field_info", THREAD)) { 2311 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2312 ("bad field_type_annotations at %d", i)); 2313 // propagate failure back to caller 2314 return false; 2315 } 2316 } 2317 2318 return true; 2319 } // end rewrite_cp_refs_in_fields_type_annotations() 2320 2321 2322 // Rewrite constant pool references in a methods_type_annotations field. 2323 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations( 2324 instanceKlassHandle scratch_class, TRAPS) { 2325 2326 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2327 Method* m = scratch_class->methods()->at(i); 2328 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations(); 2329 2330 if (method_type_annotations == NULL || method_type_annotations->length() == 0) { 2331 // this method does not have any annotations so skip it 2332 continue; 2333 } 2334 2335 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2336 ("methods type_annotations length=%d", method_type_annotations->length())); 2337 2338 int byte_i = 0; // byte index into method_type_annotations 2339 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations, 2340 byte_i, "method_info", THREAD)) { 2341 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2342 ("bad method_type_annotations at %d", i)); 2343 // propagate failure back to caller 2344 return false; 2345 } 2346 } 2347 2348 return true; 2349 } // end rewrite_cp_refs_in_methods_type_annotations() 2350 2351 2352 // Rewrite constant pool references in a type_annotations 2353 // field. This "structure" is adapted from the 2354 // RuntimeVisibleTypeAnnotations_attribute described in 2355 // section 4.7.20 of the Java SE 8 Edition of the VM spec: 2356 // 2357 // type_annotations_typeArray { 2358 // u2 num_annotations; 2359 // type_annotation annotations[num_annotations]; 2360 // } 2361 // 2362 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray( 2363 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2364 const char * location_mesg, TRAPS) { 2365 2366 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2367 // not enough room for num_annotations field 2368 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2369 ("length() is too small for num_annotations field")); 2370 return false; 2371 } 2372 2373 u2 num_annotations = Bytes::get_Java_u2((address) 2374 type_annotations_typeArray->adr_at(byte_i_ref)); 2375 byte_i_ref += 2; 2376 2377 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2378 ("num_type_annotations=%d", num_annotations)); 2379 2380 int calc_num_annotations = 0; 2381 for (; calc_num_annotations < num_annotations; calc_num_annotations++) { 2382 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray, 2383 byte_i_ref, location_mesg, THREAD)) { 2384 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2385 ("bad type_annotation_struct at %d", calc_num_annotations)); 2386 // propagate failure back to caller 2387 return false; 2388 } 2389 } 2390 assert(num_annotations == calc_num_annotations, "sanity check"); 2391 2392 if (byte_i_ref != type_annotations_typeArray->length()) { 2393 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2394 ("read wrong amount of bytes at end of processing " 2395 "type_annotations_typeArray (%d of %d bytes were read)", 2396 byte_i_ref, type_annotations_typeArray->length())); 2397 return false; 2398 } 2399 2400 return true; 2401 } // end rewrite_cp_refs_in_type_annotations_typeArray() 2402 2403 2404 // Rewrite constant pool references in a type_annotation 2405 // field. This "structure" is adapted from the 2406 // RuntimeVisibleTypeAnnotations_attribute described in 2407 // section 4.7.20 of the Java SE 8 Edition of the VM spec: 2408 // 2409 // type_annotation { 2410 // u1 target_type; 2411 // union { 2412 // type_parameter_target; 2413 // supertype_target; 2414 // type_parameter_bound_target; 2415 // empty_target; 2416 // method_formal_parameter_target; 2417 // throws_target; 2418 // localvar_target; 2419 // catch_target; 2420 // offset_target; 2421 // type_argument_target; 2422 // } target_info; 2423 // type_path target_path; 2424 // annotation anno; 2425 // } 2426 // 2427 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct( 2428 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2429 const char * location_mesg, TRAPS) { 2430 2431 if (!skip_type_annotation_target(type_annotations_typeArray, 2432 byte_i_ref, location_mesg, THREAD)) { 2433 return false; 2434 } 2435 2436 if (!skip_type_annotation_type_path(type_annotations_typeArray, 2437 byte_i_ref, THREAD)) { 2438 return false; 2439 } 2440 2441 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray, 2442 byte_i_ref, THREAD)) { 2443 return false; 2444 } 2445 2446 return true; 2447 } // end rewrite_cp_refs_in_type_annotation_struct() 2448 2449 2450 // Read, verify and skip over the target_type and target_info part 2451 // so that rewriting can continue in the later parts of the struct. 2452 // 2453 // u1 target_type; 2454 // union { 2455 // type_parameter_target; 2456 // supertype_target; 2457 // type_parameter_bound_target; 2458 // empty_target; 2459 // method_formal_parameter_target; 2460 // throws_target; 2461 // localvar_target; 2462 // catch_target; 2463 // offset_target; 2464 // type_argument_target; 2465 // } target_info; 2466 // 2467 bool VM_RedefineClasses::skip_type_annotation_target( 2468 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2469 const char * location_mesg, TRAPS) { 2470 2471 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2472 // not enough room for a target_type let alone the rest of a type_annotation 2473 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2474 ("length() is too small for a target_type")); 2475 return false; 2476 } 2477 2478 u1 target_type = type_annotations_typeArray->at(byte_i_ref); 2479 byte_i_ref += 1; 2480 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("target_type=0x%.2x", target_type)); 2481 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("location=%s", location_mesg)); 2482 2483 // Skip over target_info 2484 switch (target_type) { 2485 case 0x00: 2486 // kind: type parameter declaration of generic class or interface 2487 // location: ClassFile 2488 case 0x01: 2489 // kind: type parameter declaration of generic method or constructor 2490 // location: method_info 2491 2492 { 2493 // struct: 2494 // type_parameter_target { 2495 // u1 type_parameter_index; 2496 // } 2497 // 2498 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2499 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2500 ("length() is too small for a type_parameter_target")); 2501 return false; 2502 } 2503 2504 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2505 byte_i_ref += 1; 2506 2507 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2508 ("type_parameter_target: type_parameter_index=%d", 2509 type_parameter_index)); 2510 } break; 2511 2512 case 0x10: 2513 // kind: type in extends clause of class or interface declaration 2514 // (including the direct superclass of an anonymous class declaration), 2515 // or in implements clause of interface declaration 2516 // location: ClassFile 2517 2518 { 2519 // struct: 2520 // supertype_target { 2521 // u2 supertype_index; 2522 // } 2523 // 2524 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2525 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2526 ("length() is too small for a supertype_target")); 2527 return false; 2528 } 2529 2530 u2 supertype_index = Bytes::get_Java_u2((address) 2531 type_annotations_typeArray->adr_at(byte_i_ref)); 2532 byte_i_ref += 2; 2533 2534 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2535 ("supertype_target: supertype_index=%d", supertype_index)); 2536 } break; 2537 2538 case 0x11: 2539 // kind: type in bound of type parameter declaration of generic class or interface 2540 // location: ClassFile 2541 case 0x12: 2542 // kind: type in bound of type parameter declaration of generic method or constructor 2543 // location: method_info 2544 2545 { 2546 // struct: 2547 // type_parameter_bound_target { 2548 // u1 type_parameter_index; 2549 // u1 bound_index; 2550 // } 2551 // 2552 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2553 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2554 ("length() is too small for a type_parameter_bound_target")); 2555 return false; 2556 } 2557 2558 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2559 byte_i_ref += 1; 2560 u1 bound_index = type_annotations_typeArray->at(byte_i_ref); 2561 byte_i_ref += 1; 2562 2563 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2564 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d", 2565 type_parameter_index, bound_index)); 2566 } break; 2567 2568 case 0x13: 2569 // kind: type in field declaration 2570 // location: field_info 2571 case 0x14: 2572 // kind: return type of method, or type of newly constructed object 2573 // location: method_info 2574 case 0x15: 2575 // kind: receiver type of method or constructor 2576 // location: method_info 2577 2578 { 2579 // struct: 2580 // empty_target { 2581 // } 2582 // 2583 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2584 ("empty_target")); 2585 } break; 2586 2587 case 0x16: 2588 // kind: type in formal parameter declaration of method, constructor, or lambda expression 2589 // location: method_info 2590 2591 { 2592 // struct: 2593 // formal_parameter_target { 2594 // u1 formal_parameter_index; 2595 // } 2596 // 2597 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2598 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2599 ("length() is too small for a formal_parameter_target")); 2600 return false; 2601 } 2602 2603 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2604 byte_i_ref += 1; 2605 2606 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2607 ("formal_parameter_target: formal_parameter_index=%d", 2608 formal_parameter_index)); 2609 } break; 2610 2611 case 0x17: 2612 // kind: type in throws clause of method or constructor 2613 // location: method_info 2614 2615 { 2616 // struct: 2617 // throws_target { 2618 // u2 throws_type_index 2619 // } 2620 // 2621 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2622 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2623 ("length() is too small for a throws_target")); 2624 return false; 2625 } 2626 2627 u2 throws_type_index = Bytes::get_Java_u2((address) 2628 type_annotations_typeArray->adr_at(byte_i_ref)); 2629 byte_i_ref += 2; 2630 2631 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2632 ("throws_target: throws_type_index=%d", throws_type_index)); 2633 } break; 2634 2635 case 0x40: 2636 // kind: type in local variable declaration 2637 // location: Code 2638 case 0x41: 2639 // kind: type in resource variable declaration 2640 // location: Code 2641 2642 { 2643 // struct: 2644 // localvar_target { 2645 // u2 table_length; 2646 // struct { 2647 // u2 start_pc; 2648 // u2 length; 2649 // u2 index; 2650 // } table[table_length]; 2651 // } 2652 // 2653 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2654 // not enough room for a table_length let alone the rest of a localvar_target 2655 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2656 ("length() is too small for a localvar_target table_length")); 2657 return false; 2658 } 2659 2660 u2 table_length = Bytes::get_Java_u2((address) 2661 type_annotations_typeArray->adr_at(byte_i_ref)); 2662 byte_i_ref += 2; 2663 2664 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2665 ("localvar_target: table_length=%d", table_length)); 2666 2667 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry 2668 int table_size = table_length * table_struct_size; 2669 2670 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) { 2671 // not enough room for a table 2672 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2673 ("length() is too small for a table array of length %d", table_length)); 2674 return false; 2675 } 2676 2677 // Skip over table 2678 byte_i_ref += table_size; 2679 } break; 2680 2681 case 0x42: 2682 // kind: type in exception parameter declaration 2683 // location: Code 2684 2685 { 2686 // struct: 2687 // catch_target { 2688 // u2 exception_table_index; 2689 // } 2690 // 2691 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2692 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2693 ("length() is too small for a catch_target")); 2694 return false; 2695 } 2696 2697 u2 exception_table_index = Bytes::get_Java_u2((address) 2698 type_annotations_typeArray->adr_at(byte_i_ref)); 2699 byte_i_ref += 2; 2700 2701 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2702 ("catch_target: exception_table_index=%d", exception_table_index)); 2703 } break; 2704 2705 case 0x43: 2706 // kind: type in instanceof expression 2707 // location: Code 2708 case 0x44: 2709 // kind: type in new expression 2710 // location: Code 2711 case 0x45: 2712 // kind: type in method reference expression using ::new 2713 // location: Code 2714 case 0x46: 2715 // kind: type in method reference expression using ::Identifier 2716 // location: Code 2717 2718 { 2719 // struct: 2720 // offset_target { 2721 // u2 offset; 2722 // } 2723 // 2724 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2725 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2726 ("length() is too small for a offset_target")); 2727 return false; 2728 } 2729 2730 u2 offset = Bytes::get_Java_u2((address) 2731 type_annotations_typeArray->adr_at(byte_i_ref)); 2732 byte_i_ref += 2; 2733 2734 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2735 ("offset_target: offset=%d", offset)); 2736 } break; 2737 2738 case 0x47: 2739 // kind: type in cast expression 2740 // location: Code 2741 case 0x48: 2742 // kind: type argument for generic constructor in new expression or 2743 // explicit constructor invocation statement 2744 // location: Code 2745 case 0x49: 2746 // kind: type argument for generic method in method invocation expression 2747 // location: Code 2748 case 0x4A: 2749 // kind: type argument for generic constructor in method reference expression using ::new 2750 // location: Code 2751 case 0x4B: 2752 // kind: type argument for generic method in method reference expression using ::Identifier 2753 // location: Code 2754 2755 { 2756 // struct: 2757 // type_argument_target { 2758 // u2 offset; 2759 // u1 type_argument_index; 2760 // } 2761 // 2762 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) { 2763 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2764 ("length() is too small for a type_argument_target")); 2765 return false; 2766 } 2767 2768 u2 offset = Bytes::get_Java_u2((address) 2769 type_annotations_typeArray->adr_at(byte_i_ref)); 2770 byte_i_ref += 2; 2771 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref); 2772 byte_i_ref += 1; 2773 2774 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2775 ("type_argument_target: offset=%d, type_argument_index=%d", 2776 offset, type_argument_index)); 2777 } break; 2778 2779 default: 2780 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2781 ("unknown target_type")); 2782 #ifdef ASSERT 2783 ShouldNotReachHere(); 2784 #endif 2785 return false; 2786 } 2787 2788 return true; 2789 } // end skip_type_annotation_target() 2790 2791 2792 // Read, verify and skip over the type_path part so that rewriting 2793 // can continue in the later parts of the struct. 2794 // 2795 // type_path { 2796 // u1 path_length; 2797 // { 2798 // u1 type_path_kind; 2799 // u1 type_argument_index; 2800 // } path[path_length]; 2801 // } 2802 // 2803 bool VM_RedefineClasses::skip_type_annotation_type_path( 2804 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, TRAPS) { 2805 2806 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2807 // not enough room for a path_length let alone the rest of the type_path 2808 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2809 ("length() is too small for a type_path")); 2810 return false; 2811 } 2812 2813 u1 path_length = type_annotations_typeArray->at(byte_i_ref); 2814 byte_i_ref += 1; 2815 2816 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2817 ("type_path: path_length=%d", path_length)); 2818 2819 int calc_path_length = 0; 2820 for (; calc_path_length < path_length; calc_path_length++) { 2821 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) { 2822 // not enough room for a path 2823 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2824 ("length() is too small for path entry %d of %d", 2825 calc_path_length, path_length)); 2826 return false; 2827 } 2828 2829 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref); 2830 byte_i_ref += 1; 2831 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref); 2832 byte_i_ref += 1; 2833 2834 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2835 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d", 2836 calc_path_length, type_path_kind, type_argument_index)); 2837 2838 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) { 2839 // not enough room for a path 2840 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2841 ("inconsistent type_path values")); 2842 return false; 2843 } 2844 } 2845 assert(path_length == calc_path_length, "sanity check"); 2846 2847 return true; 2848 } // end skip_type_annotation_type_path() 2849 2850 2851 // Rewrite constant pool references in the method's stackmap table. 2852 // These "structures" are adapted from the StackMapTable_attribute that 2853 // is described in section 4.8.4 of the 6.0 version of the VM spec 2854 // (dated 2005.10.26): 2855 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf 2856 // 2857 // stack_map { 2858 // u2 number_of_entries; 2859 // stack_map_frame entries[number_of_entries]; 2860 // } 2861 // 2862 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table( 2863 methodHandle method, TRAPS) { 2864 2865 if (!method->has_stackmap_table()) { 2866 return; 2867 } 2868 2869 AnnotationArray* stackmap_data = method->stackmap_data(); 2870 address stackmap_p = (address)stackmap_data->adr_at(0); 2871 address stackmap_end = stackmap_p + stackmap_data->length(); 2872 2873 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries"); 2874 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p); 2875 stackmap_p += 2; 2876 2877 RC_TRACE_WITH_THREAD(0x04000000, THREAD, 2878 ("number_of_entries=%u", number_of_entries)); 2879 2880 // walk through each stack_map_frame 2881 u2 calc_number_of_entries = 0; 2882 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) { 2883 // The stack_map_frame structure is a u1 frame_type followed by 2884 // 0 or more bytes of data: 2885 // 2886 // union stack_map_frame { 2887 // same_frame; 2888 // same_locals_1_stack_item_frame; 2889 // same_locals_1_stack_item_frame_extended; 2890 // chop_frame; 2891 // same_frame_extended; 2892 // append_frame; 2893 // full_frame; 2894 // } 2895 2896 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type"); 2897 // The Linux compiler does not like frame_type to be u1 or u2. It 2898 // issues the following warning for the first if-statement below: 2899 // 2900 // "warning: comparison is always true due to limited range of data type" 2901 // 2902 u4 frame_type = *stackmap_p; 2903 stackmap_p++; 2904 2905 // same_frame { 2906 // u1 frame_type = SAME; /* 0-63 */ 2907 // } 2908 if (frame_type >= 0 && frame_type <= 63) { 2909 // nothing more to do for same_frame 2910 } 2911 2912 // same_locals_1_stack_item_frame { 2913 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */ 2914 // verification_type_info stack[1]; 2915 // } 2916 else if (frame_type >= 64 && frame_type <= 127) { 2917 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2918 calc_number_of_entries, frame_type, THREAD); 2919 } 2920 2921 // reserved for future use 2922 else if (frame_type >= 128 && frame_type <= 246) { 2923 // nothing more to do for reserved frame_types 2924 } 2925 2926 // same_locals_1_stack_item_frame_extended { 2927 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */ 2928 // u2 offset_delta; 2929 // verification_type_info stack[1]; 2930 // } 2931 else if (frame_type == 247) { 2932 stackmap_p += 2; 2933 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2934 calc_number_of_entries, frame_type, THREAD); 2935 } 2936 2937 // chop_frame { 2938 // u1 frame_type = CHOP; /* 248-250 */ 2939 // u2 offset_delta; 2940 // } 2941 else if (frame_type >= 248 && frame_type <= 250) { 2942 stackmap_p += 2; 2943 } 2944 2945 // same_frame_extended { 2946 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/ 2947 // u2 offset_delta; 2948 // } 2949 else if (frame_type == 251) { 2950 stackmap_p += 2; 2951 } 2952 2953 // append_frame { 2954 // u1 frame_type = APPEND; /* 252-254 */ 2955 // u2 offset_delta; 2956 // verification_type_info locals[frame_type - 251]; 2957 // } 2958 else if (frame_type >= 252 && frame_type <= 254) { 2959 assert(stackmap_p + 2 <= stackmap_end, 2960 "no room for offset_delta"); 2961 stackmap_p += 2; 2962 u1 len = frame_type - 251; 2963 for (u1 i = 0; i < len; i++) { 2964 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2965 calc_number_of_entries, frame_type, THREAD); 2966 } 2967 } 2968 2969 // full_frame { 2970 // u1 frame_type = FULL_FRAME; /* 255 */ 2971 // u2 offset_delta; 2972 // u2 number_of_locals; 2973 // verification_type_info locals[number_of_locals]; 2974 // u2 number_of_stack_items; 2975 // verification_type_info stack[number_of_stack_items]; 2976 // } 2977 else if (frame_type == 255) { 2978 assert(stackmap_p + 2 + 2 <= stackmap_end, 2979 "no room for smallest full_frame"); 2980 stackmap_p += 2; 2981 2982 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p); 2983 stackmap_p += 2; 2984 2985 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) { 2986 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2987 calc_number_of_entries, frame_type, THREAD); 2988 } 2989 2990 // Use the largest size for the number_of_stack_items, but only get 2991 // the right number of bytes. 2992 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p); 2993 stackmap_p += 2; 2994 2995 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) { 2996 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2997 calc_number_of_entries, frame_type, THREAD); 2998 } 2999 } 3000 } // end while there is a stack_map_frame 3001 assert(number_of_entries == calc_number_of_entries, "sanity check"); 3002 } // end rewrite_cp_refs_in_stack_map_table() 3003 3004 3005 // Rewrite constant pool references in the verification type info 3006 // portion of the method's stackmap table. These "structures" are 3007 // adapted from the StackMapTable_attribute that is described in 3008 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26): 3009 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf 3010 // 3011 // The verification_type_info structure is a u1 tag followed by 0 or 3012 // more bytes of data: 3013 // 3014 // union verification_type_info { 3015 // Top_variable_info; 3016 // Integer_variable_info; 3017 // Float_variable_info; 3018 // Long_variable_info; 3019 // Double_variable_info; 3020 // Null_variable_info; 3021 // UninitializedThis_variable_info; 3022 // Object_variable_info; 3023 // Uninitialized_variable_info; 3024 // } 3025 // 3026 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info( 3027 address& stackmap_p_ref, address stackmap_end, u2 frame_i, 3028 u1 frame_type, TRAPS) { 3029 3030 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag"); 3031 u1 tag = *stackmap_p_ref; 3032 stackmap_p_ref++; 3033 3034 switch (tag) { 3035 // Top_variable_info { 3036 // u1 tag = ITEM_Top; /* 0 */ 3037 // } 3038 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top 3039 case 0: // fall through 3040 3041 // Integer_variable_info { 3042 // u1 tag = ITEM_Integer; /* 1 */ 3043 // } 3044 case ITEM_Integer: // fall through 3045 3046 // Float_variable_info { 3047 // u1 tag = ITEM_Float; /* 2 */ 3048 // } 3049 case ITEM_Float: // fall through 3050 3051 // Double_variable_info { 3052 // u1 tag = ITEM_Double; /* 3 */ 3053 // } 3054 case ITEM_Double: // fall through 3055 3056 // Long_variable_info { 3057 // u1 tag = ITEM_Long; /* 4 */ 3058 // } 3059 case ITEM_Long: // fall through 3060 3061 // Null_variable_info { 3062 // u1 tag = ITEM_Null; /* 5 */ 3063 // } 3064 case ITEM_Null: // fall through 3065 3066 // UninitializedThis_variable_info { 3067 // u1 tag = ITEM_UninitializedThis; /* 6 */ 3068 // } 3069 case ITEM_UninitializedThis: 3070 // nothing more to do for the above tag types 3071 break; 3072 3073 // Object_variable_info { 3074 // u1 tag = ITEM_Object; /* 7 */ 3075 // u2 cpool_index; 3076 // } 3077 case ITEM_Object: 3078 { 3079 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index"); 3080 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref); 3081 u2 new_cp_index = find_new_index(cpool_index); 3082 if (new_cp_index != 0) { 3083 RC_TRACE_WITH_THREAD(0x04000000, THREAD, 3084 ("mapped old cpool_index=%d", cpool_index)); 3085 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index); 3086 cpool_index = new_cp_index; 3087 } 3088 stackmap_p_ref += 2; 3089 3090 RC_TRACE_WITH_THREAD(0x04000000, THREAD, 3091 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i, 3092 frame_type, cpool_index)); 3093 } break; 3094 3095 // Uninitialized_variable_info { 3096 // u1 tag = ITEM_Uninitialized; /* 8 */ 3097 // u2 offset; 3098 // } 3099 case ITEM_Uninitialized: 3100 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset"); 3101 stackmap_p_ref += 2; 3102 break; 3103 3104 default: 3105 RC_TRACE_WITH_THREAD(0x04000000, THREAD, 3106 ("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag)); 3107 ShouldNotReachHere(); 3108 break; 3109 } // end switch (tag) 3110 } // end rewrite_cp_refs_in_verification_type_info() 3111 3112 3113 // Change the constant pool associated with klass scratch_class to 3114 // scratch_cp. If shrink is true, then scratch_cp_length elements 3115 // are copied from scratch_cp to a smaller constant pool and the 3116 // smaller constant pool is associated with scratch_class. 3117 void VM_RedefineClasses::set_new_constant_pool( 3118 ClassLoaderData* loader_data, 3119 instanceKlassHandle scratch_class, constantPoolHandle scratch_cp, 3120 int scratch_cp_length, TRAPS) { 3121 assert(scratch_cp->length() >= scratch_cp_length, "sanity check"); 3122 3123 // scratch_cp is a merged constant pool and has enough space for a 3124 // worst case merge situation. We want to associate the minimum 3125 // sized constant pool with the klass to save space. 3126 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK); 3127 constantPoolHandle smaller_cp(THREAD, cp); 3128 3129 // preserve version() value in the smaller copy 3130 int version = scratch_cp->version(); 3131 assert(version != 0, "sanity check"); 3132 smaller_cp->set_version(version); 3133 3134 // attach klass to new constant pool 3135 // reference to the cp holder is needed for copy_operands() 3136 smaller_cp->set_pool_holder(scratch_class()); 3137 3138 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD); 3139 if (HAS_PENDING_EXCEPTION) { 3140 // Exception is handled in the caller 3141 loader_data->add_to_deallocate_list(smaller_cp()); 3142 return; 3143 } 3144 scratch_cp = smaller_cp; 3145 3146 // attach new constant pool to klass 3147 scratch_class->set_constants(scratch_cp()); 3148 3149 int i; // for portability 3150 3151 // update each field in klass to use new constant pool indices as needed 3152 for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) { 3153 jshort cur_index = fs.name_index(); 3154 jshort new_index = find_new_index(cur_index); 3155 if (new_index != 0) { 3156 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3157 ("field-name_index change: %d to %d", cur_index, new_index)); 3158 fs.set_name_index(new_index); 3159 } 3160 cur_index = fs.signature_index(); 3161 new_index = find_new_index(cur_index); 3162 if (new_index != 0) { 3163 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3164 ("field-signature_index change: %d to %d", cur_index, new_index)); 3165 fs.set_signature_index(new_index); 3166 } 3167 cur_index = fs.initval_index(); 3168 new_index = find_new_index(cur_index); 3169 if (new_index != 0) { 3170 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3171 ("field-initval_index change: %d to %d", cur_index, new_index)); 3172 fs.set_initval_index(new_index); 3173 } 3174 cur_index = fs.generic_signature_index(); 3175 new_index = find_new_index(cur_index); 3176 if (new_index != 0) { 3177 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3178 ("field-generic_signature change: %d to %d", cur_index, new_index)); 3179 fs.set_generic_signature_index(new_index); 3180 } 3181 } // end for each field 3182 3183 // Update constant pool indices in the inner classes info to use 3184 // new constant indices as needed. The inner classes info is a 3185 // quadruple: 3186 // (inner_class_info, outer_class_info, inner_name, inner_access_flags) 3187 InnerClassesIterator iter(scratch_class); 3188 for (; !iter.done(); iter.next()) { 3189 int cur_index = iter.inner_class_info_index(); 3190 if (cur_index == 0) { 3191 continue; // JVM spec. allows null inner class refs so skip it 3192 } 3193 int new_index = find_new_index(cur_index); 3194 if (new_index != 0) { 3195 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3196 ("inner_class_info change: %d to %d", cur_index, new_index)); 3197 iter.set_inner_class_info_index(new_index); 3198 } 3199 cur_index = iter.outer_class_info_index(); 3200 new_index = find_new_index(cur_index); 3201 if (new_index != 0) { 3202 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3203 ("outer_class_info change: %d to %d", cur_index, new_index)); 3204 iter.set_outer_class_info_index(new_index); 3205 } 3206 cur_index = iter.inner_name_index(); 3207 new_index = find_new_index(cur_index); 3208 if (new_index != 0) { 3209 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3210 ("inner_name change: %d to %d", cur_index, new_index)); 3211 iter.set_inner_name_index(new_index); 3212 } 3213 } // end for each inner class 3214 3215 // Attach each method in klass to the new constant pool and update 3216 // to use new constant pool indices as needed: 3217 Array<Method*>* methods = scratch_class->methods(); 3218 for (i = methods->length() - 1; i >= 0; i--) { 3219 methodHandle method(THREAD, methods->at(i)); 3220 method->set_constants(scratch_cp()); 3221 3222 int new_index = find_new_index(method->name_index()); 3223 if (new_index != 0) { 3224 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3225 ("method-name_index change: %d to %d", method->name_index(), 3226 new_index)); 3227 method->set_name_index(new_index); 3228 } 3229 new_index = find_new_index(method->signature_index()); 3230 if (new_index != 0) { 3231 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3232 ("method-signature_index change: %d to %d", 3233 method->signature_index(), new_index)); 3234 method->set_signature_index(new_index); 3235 } 3236 new_index = find_new_index(method->generic_signature_index()); 3237 if (new_index != 0) { 3238 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3239 ("method-generic_signature_index change: %d to %d", 3240 method->generic_signature_index(), new_index)); 3241 method->set_generic_signature_index(new_index); 3242 } 3243 3244 // Update constant pool indices in the method's checked exception 3245 // table to use new constant indices as needed. 3246 int cext_length = method->checked_exceptions_length(); 3247 if (cext_length > 0) { 3248 CheckedExceptionElement * cext_table = 3249 method->checked_exceptions_start(); 3250 for (int j = 0; j < cext_length; j++) { 3251 int cur_index = cext_table[j].class_cp_index; 3252 int new_index = find_new_index(cur_index); 3253 if (new_index != 0) { 3254 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3255 ("cext-class_cp_index change: %d to %d", cur_index, new_index)); 3256 cext_table[j].class_cp_index = (u2)new_index; 3257 } 3258 } // end for each checked exception table entry 3259 } // end if there are checked exception table entries 3260 3261 // Update each catch type index in the method's exception table 3262 // to use new constant pool indices as needed. The exception table 3263 // holds quadruple entries of the form: 3264 // (beg_bci, end_bci, handler_bci, klass_index) 3265 3266 ExceptionTable ex_table(method()); 3267 int ext_length = ex_table.length(); 3268 3269 for (int j = 0; j < ext_length; j ++) { 3270 int cur_index = ex_table.catch_type_index(j); 3271 int new_index = find_new_index(cur_index); 3272 if (new_index != 0) { 3273 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3274 ("ext-klass_index change: %d to %d", cur_index, new_index)); 3275 ex_table.set_catch_type_index(j, new_index); 3276 } 3277 } // end for each exception table entry 3278 3279 // Update constant pool indices in the method's local variable 3280 // table to use new constant indices as needed. The local variable 3281 // table hold sextuple entries of the form: 3282 // (start_pc, length, name_index, descriptor_index, signature_index, slot) 3283 int lvt_length = method->localvariable_table_length(); 3284 if (lvt_length > 0) { 3285 LocalVariableTableElement * lv_table = 3286 method->localvariable_table_start(); 3287 for (int j = 0; j < lvt_length; j++) { 3288 int cur_index = lv_table[j].name_cp_index; 3289 int new_index = find_new_index(cur_index); 3290 if (new_index != 0) { 3291 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3292 ("lvt-name_cp_index change: %d to %d", cur_index, new_index)); 3293 lv_table[j].name_cp_index = (u2)new_index; 3294 } 3295 cur_index = lv_table[j].descriptor_cp_index; 3296 new_index = find_new_index(cur_index); 3297 if (new_index != 0) { 3298 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3299 ("lvt-descriptor_cp_index change: %d to %d", cur_index, 3300 new_index)); 3301 lv_table[j].descriptor_cp_index = (u2)new_index; 3302 } 3303 cur_index = lv_table[j].signature_cp_index; 3304 new_index = find_new_index(cur_index); 3305 if (new_index != 0) { 3306 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3307 ("lvt-signature_cp_index change: %d to %d", cur_index, new_index)); 3308 lv_table[j].signature_cp_index = (u2)new_index; 3309 } 3310 } // end for each local variable table entry 3311 } // end if there are local variable table entries 3312 3313 rewrite_cp_refs_in_stack_map_table(method, THREAD); 3314 } // end for each method 3315 } // end set_new_constant_pool() 3316 3317 3318 // Unevolving classes may point to methods of the_class directly 3319 // from their constant pool caches, itables, and/or vtables. We 3320 // use the ClassLoaderDataGraph::classes_do() facility and this helper 3321 // to fix up these pointers. 3322 3323 // Adjust cpools and vtables closure 3324 void VM_RedefineClasses::AdjustCpoolCacheAndVtable::do_klass(Klass* k) { 3325 3326 // This is a very busy routine. We don't want too much tracing 3327 // printed out. 3328 bool trace_name_printed = false; 3329 3330 // Very noisy: only enable this call if you are trying to determine 3331 // that a specific class gets found by this routine. 3332 // RC_TRACE macro has an embedded ResourceMark 3333 // RC_TRACE_WITH_THREAD(0x00100000, THREAD, 3334 // ("adjust check: name=%s", k->external_name())); 3335 // trace_name_printed = true; 3336 3337 // If the class being redefined is java.lang.Object, we need to fix all 3338 // array class vtables also 3339 if (k->oop_is_array() && _the_class_oop == SystemDictionary::Object_klass()) { 3340 k->vtable()->adjust_method_entries(_matching_old_methods, 3341 _matching_new_methods, 3342 _matching_methods_length, 3343 &trace_name_printed); 3344 } else if (k->oop_is_instance()) { 3345 HandleMark hm(_thread); 3346 InstanceKlass *ik = InstanceKlass::cast(k); 3347 3348 // HotSpot specific optimization! HotSpot does not currently 3349 // support delegation from the bootstrap class loader to a 3350 // user-defined class loader. This means that if the bootstrap 3351 // class loader is the initiating class loader, then it will also 3352 // be the defining class loader. This also means that classes 3353 // loaded by the bootstrap class loader cannot refer to classes 3354 // loaded by a user-defined class loader. Note: a user-defined 3355 // class loader can delegate to the bootstrap class loader. 3356 // 3357 // If the current class being redefined has a user-defined class 3358 // loader as its defining class loader, then we can skip all 3359 // classes loaded by the bootstrap class loader. 3360 bool is_user_defined = 3361 InstanceKlass::cast(_the_class_oop)->class_loader() != NULL; 3362 if (is_user_defined && ik->class_loader() == NULL) { 3363 return; 3364 } 3365 3366 // Fix the vtable embedded in the_class and subclasses of the_class, 3367 // if one exists. We discard scratch_class and we don't keep an 3368 // InstanceKlass around to hold obsolete methods so we don't have 3369 // any other InstanceKlass embedded vtables to update. The vtable 3370 // holds the Method*s for virtual (but not final) methods. 3371 // Default methods, or concrete methods in interfaces are stored 3372 // in the vtable, so if an interface changes we need to check 3373 // adjust_method_entries() for every InstanceKlass, which will also 3374 // adjust the default method vtable indices. 3375 // We also need to adjust any default method entries that are 3376 // not yet in the vtable, because the vtable setup is in progress. 3377 // This must be done after we adjust the default_methods and 3378 // default_vtable_indices for methods already in the vtable. 3379 if (ik->vtable_length() > 0 && (_the_class_oop->is_interface() 3380 || ik->is_subtype_of(_the_class_oop))) { 3381 // ik->vtable() creates a wrapper object; rm cleans it up 3382 ResourceMark rm(_thread); 3383 ik->vtable()->adjust_method_entries(_matching_old_methods, 3384 _matching_new_methods, 3385 _matching_methods_length, 3386 &trace_name_printed); 3387 ik->adjust_default_methods(_matching_old_methods, 3388 _matching_new_methods, 3389 _matching_methods_length, 3390 &trace_name_printed); 3391 } 3392 3393 // If the current class has an itable and we are either redefining an 3394 // interface or if the current class is a subclass of the_class, then 3395 // we potentially have to fix the itable. If we are redefining an 3396 // interface, then we have to call adjust_method_entries() for 3397 // every InstanceKlass that has an itable since there isn't a 3398 // subclass relationship between an interface and an InstanceKlass. 3399 if (ik->itable_length() > 0 && (_the_class_oop->is_interface() 3400 || ik->is_subclass_of(_the_class_oop))) { 3401 // ik->itable() creates a wrapper object; rm cleans it up 3402 ResourceMark rm(_thread); 3403 ik->itable()->adjust_method_entries(_matching_old_methods, 3404 _matching_new_methods, 3405 _matching_methods_length, 3406 &trace_name_printed); 3407 } 3408 3409 // The constant pools in other classes (other_cp) can refer to 3410 // methods in the_class. We have to update method information in 3411 // other_cp's cache. If other_cp has a previous version, then we 3412 // have to repeat the process for each previous version. The 3413 // constant pool cache holds the Method*s for non-virtual 3414 // methods and for virtual, final methods. 3415 // 3416 // Special case: if the current class is the_class, then new_cp 3417 // has already been attached to the_class and old_cp has already 3418 // been added as a previous version. The new_cp doesn't have any 3419 // cached references to old methods so it doesn't need to be 3420 // updated. We can simply start with the previous version(s) in 3421 // that case. 3422 constantPoolHandle other_cp; 3423 ConstantPoolCache* cp_cache; 3424 3425 if (ik != _the_class_oop) { 3426 // this klass' constant pool cache may need adjustment 3427 other_cp = constantPoolHandle(ik->constants()); 3428 cp_cache = other_cp->cache(); 3429 if (cp_cache != NULL) { 3430 cp_cache->adjust_method_entries(_matching_old_methods, 3431 _matching_new_methods, 3432 _matching_methods_length, 3433 &trace_name_printed); 3434 } 3435 } 3436 3437 // the previous versions' constant pool caches may need adjustment 3438 for (InstanceKlass* pv_node = ik->previous_versions(); 3439 pv_node != NULL; 3440 pv_node = pv_node->previous_versions()) { 3441 cp_cache = pv_node->constants()->cache(); 3442 if (cp_cache != NULL) { 3443 cp_cache->adjust_method_entries(_matching_old_methods, 3444 _matching_new_methods, 3445 _matching_methods_length, 3446 &trace_name_printed); 3447 } 3448 } 3449 } 3450 } 3451 3452 // Clean method data for this class 3453 void VM_RedefineClasses::MethodDataCleaner::do_klass(Klass* k) { 3454 if (k->oop_is_instance()) { 3455 InstanceKlass *ik = InstanceKlass::cast(k); 3456 // Clean MethodData of this class's methods so they don't refer to 3457 // old methods that are no longer running. 3458 Array<Method*>* methods = ik->methods(); 3459 int num_methods = methods->length(); 3460 for (int index = 0; index < num_methods; ++index) { 3461 if (methods->at(index)->method_data() != NULL) { 3462 methods->at(index)->method_data()->clean_weak_method_links(); 3463 } 3464 } 3465 } 3466 } 3467 3468 void VM_RedefineClasses::update_jmethod_ids() { 3469 for (int j = 0; j < _matching_methods_length; ++j) { 3470 Method* old_method = _matching_old_methods[j]; 3471 jmethodID jmid = old_method->find_jmethod_id_or_null(); 3472 if (jmid != NULL) { 3473 // There is a jmethodID, change it to point to the new method 3474 methodHandle new_method_h(_matching_new_methods[j]); 3475 Method::change_method_associated_with_jmethod_id(jmid, new_method_h()); 3476 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j], 3477 "should be replaced"); 3478 } 3479 } 3480 } 3481 3482 int VM_RedefineClasses::check_methods_and_mark_as_obsolete() { 3483 int emcp_method_count = 0; 3484 int obsolete_count = 0; 3485 int old_index = 0; 3486 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) { 3487 Method* old_method = _matching_old_methods[j]; 3488 Method* new_method = _matching_new_methods[j]; 3489 Method* old_array_method; 3490 3491 // Maintain an old_index into the _old_methods array by skipping 3492 // deleted methods 3493 while ((old_array_method = _old_methods->at(old_index)) != old_method) { 3494 ++old_index; 3495 } 3496 3497 if (MethodComparator::methods_EMCP(old_method, new_method)) { 3498 // The EMCP definition from JSR-163 requires the bytecodes to be 3499 // the same with the exception of constant pool indices which may 3500 // differ. However, the constants referred to by those indices 3501 // must be the same. 3502 // 3503 // We use methods_EMCP() for comparison since constant pool 3504 // merging can remove duplicate constant pool entries that were 3505 // present in the old method and removed from the rewritten new 3506 // method. A faster binary comparison function would consider the 3507 // old and new methods to be different when they are actually 3508 // EMCP. 3509 // 3510 // The old and new methods are EMCP and you would think that we 3511 // could get rid of one of them here and now and save some space. 3512 // However, the concept of EMCP only considers the bytecodes and 3513 // the constant pool entries in the comparison. Other things, 3514 // e.g., the line number table (LNT) or the local variable table 3515 // (LVT) don't count in the comparison. So the new (and EMCP) 3516 // method can have a new LNT that we need so we can't just 3517 // overwrite the new method with the old method. 3518 // 3519 // When this routine is called, we have already attached the new 3520 // methods to the_class so the old methods are effectively 3521 // overwritten. However, if an old method is still executing, 3522 // then the old method cannot be collected until sometime after 3523 // the old method call has returned. So the overwriting of old 3524 // methods by new methods will save us space except for those 3525 // (hopefully few) old methods that are still executing. 3526 // 3527 // A method refers to a ConstMethod* and this presents another 3528 // possible avenue to space savings. The ConstMethod* in the 3529 // new method contains possibly new attributes (LNT, LVT, etc). 3530 // At first glance, it seems possible to save space by replacing 3531 // the ConstMethod* in the old method with the ConstMethod* 3532 // from the new method. The old and new methods would share the 3533 // same ConstMethod* and we would save the space occupied by 3534 // the old ConstMethod*. However, the ConstMethod* contains 3535 // a back reference to the containing method. Sharing the 3536 // ConstMethod* between two methods could lead to confusion in 3537 // the code that uses the back reference. This would lead to 3538 // brittle code that could be broken in non-obvious ways now or 3539 // in the future. 3540 // 3541 // Another possibility is to copy the ConstMethod* from the new 3542 // method to the old method and then overwrite the new method with 3543 // the old method. Since the ConstMethod* contains the bytecodes 3544 // for the method embedded in the oop, this option would change 3545 // the bytecodes out from under any threads executing the old 3546 // method and make the thread's bcp invalid. Since EMCP requires 3547 // that the bytecodes be the same modulo constant pool indices, it 3548 // is straight forward to compute the correct new bcp in the new 3549 // ConstMethod* from the old bcp in the old ConstMethod*. The 3550 // time consuming part would be searching all the frames in all 3551 // of the threads to find all of the calls to the old method. 3552 // 3553 // It looks like we will have to live with the limited savings 3554 // that we get from effectively overwriting the old methods 3555 // when the new methods are attached to the_class. 3556 3557 // Count number of methods that are EMCP. The method will be marked 3558 // old but not obsolete if it is EMCP. 3559 emcp_method_count++; 3560 3561 // An EMCP method is _not_ obsolete. An obsolete method has a 3562 // different jmethodID than the current method. An EMCP method 3563 // has the same jmethodID as the current method. Having the 3564 // same jmethodID for all EMCP versions of a method allows for 3565 // a consistent view of the EMCP methods regardless of which 3566 // EMCP method you happen to have in hand. For example, a 3567 // breakpoint set in one EMCP method will work for all EMCP 3568 // versions of the method including the current one. 3569 } else { 3570 // mark obsolete methods as such 3571 old_method->set_is_obsolete(); 3572 obsolete_count++; 3573 3574 // obsolete methods need a unique idnum so they become new entries in 3575 // the jmethodID cache in InstanceKlass 3576 u2 num = InstanceKlass::cast(_the_class_oop)->next_method_idnum(); 3577 if (num != ConstMethod::UNSET_IDNUM) { 3578 old_method->set_method_idnum(num); 3579 } 3580 3581 // With tracing we try not to "yack" too much. The position of 3582 // this trace assumes there are fewer obsolete methods than 3583 // EMCP methods. 3584 RC_TRACE(0x00000100, ("mark %s(%s) as obsolete", 3585 old_method->name()->as_C_string(), 3586 old_method->signature()->as_C_string())); 3587 } 3588 old_method->set_is_old(); 3589 } 3590 for (int i = 0; i < _deleted_methods_length; ++i) { 3591 Method* old_method = _deleted_methods[i]; 3592 3593 assert(!old_method->has_vtable_index(), 3594 "cannot delete methods with vtable entries");; 3595 3596 // Mark all deleted methods as old, obsolete and deleted 3597 old_method->set_is_deleted(); 3598 old_method->set_is_old(); 3599 old_method->set_is_obsolete(); 3600 ++obsolete_count; 3601 // With tracing we try not to "yack" too much. The position of 3602 // this trace assumes there are fewer obsolete methods than 3603 // EMCP methods. 3604 RC_TRACE(0x00000100, ("mark deleted %s(%s) as obsolete", 3605 old_method->name()->as_C_string(), 3606 old_method->signature()->as_C_string())); 3607 } 3608 assert((emcp_method_count + obsolete_count) == _old_methods->length(), 3609 "sanity check"); 3610 RC_TRACE(0x00000100, ("EMCP_cnt=%d, obsolete_cnt=%d", emcp_method_count, 3611 obsolete_count)); 3612 return emcp_method_count; 3613 } 3614 3615 // This internal class transfers the native function registration from old methods 3616 // to new methods. It is designed to handle both the simple case of unchanged 3617 // native methods and the complex cases of native method prefixes being added and/or 3618 // removed. 3619 // It expects only to be used during the VM_RedefineClasses op (a safepoint). 3620 // 3621 // This class is used after the new methods have been installed in "the_class". 3622 // 3623 // So, for example, the following must be handled. Where 'm' is a method and 3624 // a number followed by an underscore is a prefix. 3625 // 3626 // Old Name New Name 3627 // Simple transfer to new method m -> m 3628 // Add prefix m -> 1_m 3629 // Remove prefix 1_m -> m 3630 // Simultaneous add of prefixes m -> 3_2_1_m 3631 // Simultaneous removal of prefixes 3_2_1_m -> m 3632 // Simultaneous add and remove 1_m -> 2_m 3633 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m 3634 // 3635 class TransferNativeFunctionRegistration { 3636 private: 3637 instanceKlassHandle the_class; 3638 int prefix_count; 3639 char** prefixes; 3640 3641 // Recursively search the binary tree of possibly prefixed method names. 3642 // Iteration could be used if all agents were well behaved. Full tree walk is 3643 // more resilent to agents not cleaning up intermediate methods. 3644 // Branch at each depth in the binary tree is: 3645 // (1) without the prefix. 3646 // (2) with the prefix. 3647 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...) 3648 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len, 3649 Symbol* signature) { 3650 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len); 3651 if (name_symbol != NULL) { 3652 Method* method = the_class()->lookup_method(name_symbol, signature); 3653 if (method != NULL) { 3654 // Even if prefixed, intermediate methods must exist. 3655 if (method->is_native()) { 3656 // Wahoo, we found a (possibly prefixed) version of the method, return it. 3657 return method; 3658 } 3659 if (depth < prefix_count) { 3660 // Try applying further prefixes (other than this one). 3661 method = search_prefix_name_space(depth+1, name_str, name_len, signature); 3662 if (method != NULL) { 3663 return method; // found 3664 } 3665 3666 // Try adding this prefix to the method name and see if it matches 3667 // another method name. 3668 char* prefix = prefixes[depth]; 3669 size_t prefix_len = strlen(prefix); 3670 size_t trial_len = name_len + prefix_len; 3671 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1); 3672 strcpy(trial_name_str, prefix); 3673 strcat(trial_name_str, name_str); 3674 method = search_prefix_name_space(depth+1, trial_name_str, trial_len, 3675 signature); 3676 if (method != NULL) { 3677 // If found along this branch, it was prefixed, mark as such 3678 method->set_is_prefixed_native(); 3679 return method; // found 3680 } 3681 } 3682 } 3683 } 3684 return NULL; // This whole branch bore nothing 3685 } 3686 3687 // Return the method name with old prefixes stripped away. 3688 char* method_name_without_prefixes(Method* method) { 3689 Symbol* name = method->name(); 3690 char* name_str = name->as_utf8(); 3691 3692 // Old prefixing may be defunct, strip prefixes, if any. 3693 for (int i = prefix_count-1; i >= 0; i--) { 3694 char* prefix = prefixes[i]; 3695 size_t prefix_len = strlen(prefix); 3696 if (strncmp(prefix, name_str, prefix_len) == 0) { 3697 name_str += prefix_len; 3698 } 3699 } 3700 return name_str; 3701 } 3702 3703 // Strip any prefixes off the old native method, then try to find a 3704 // (possibly prefixed) new native that matches it. 3705 Method* strip_and_search_for_new_native(Method* method) { 3706 ResourceMark rm; 3707 char* name_str = method_name_without_prefixes(method); 3708 return search_prefix_name_space(0, name_str, strlen(name_str), 3709 method->signature()); 3710 } 3711 3712 public: 3713 3714 // Construct a native method transfer processor for this class. 3715 TransferNativeFunctionRegistration(instanceKlassHandle _the_class) { 3716 assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); 3717 3718 the_class = _the_class; 3719 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count); 3720 } 3721 3722 // Attempt to transfer any of the old or deleted methods that are native 3723 void transfer_registrations(Method** old_methods, int methods_length) { 3724 for (int j = 0; j < methods_length; j++) { 3725 Method* old_method = old_methods[j]; 3726 3727 if (old_method->is_native() && old_method->has_native_function()) { 3728 Method* new_method = strip_and_search_for_new_native(old_method); 3729 if (new_method != NULL) { 3730 // Actually set the native function in the new method. 3731 // Redefine does not send events (except CFLH), certainly not this 3732 // behind the scenes re-registration. 3733 new_method->set_native_function(old_method->native_function(), 3734 !Method::native_bind_event_is_interesting); 3735 } 3736 } 3737 } 3738 } 3739 }; 3740 3741 // Don't lose the association between a native method and its JNI function. 3742 void VM_RedefineClasses::transfer_old_native_function_registrations(instanceKlassHandle the_class) { 3743 TransferNativeFunctionRegistration transfer(the_class); 3744 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length); 3745 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length); 3746 } 3747 3748 // Deoptimize all compiled code that depends on this class. 3749 // 3750 // If the can_redefine_classes capability is obtained in the onload 3751 // phase then the compiler has recorded all dependencies from startup. 3752 // In that case we need only deoptimize and throw away all compiled code 3753 // that depends on the class. 3754 // 3755 // If can_redefine_classes is obtained sometime after the onload 3756 // phase then the dependency information may be incomplete. In that case 3757 // the first call to RedefineClasses causes all compiled code to be 3758 // thrown away. As can_redefine_classes has been obtained then 3759 // all future compilations will record dependencies so second and 3760 // subsequent calls to RedefineClasses need only throw away code 3761 // that depends on the class. 3762 // 3763 void VM_RedefineClasses::flush_dependent_code(instanceKlassHandle k_h, TRAPS) { 3764 assert_locked_or_safepoint(Compile_lock); 3765 3766 // All dependencies have been recorded from startup or this is a second or 3767 // subsequent use of RedefineClasses 3768 if (JvmtiExport::all_dependencies_are_recorded()) { 3769 Universe::flush_evol_dependents_on(k_h); 3770 } else { 3771 CodeCache::mark_all_nmethods_for_deoptimization(); 3772 3773 ResourceMark rm(THREAD); 3774 DeoptimizationMarker dm; 3775 3776 // Deoptimize all activations depending on marked nmethods 3777 Deoptimization::deoptimize_dependents(); 3778 3779 // Make the dependent methods not entrant (in VM_Deoptimize they are made zombies) 3780 CodeCache::make_marked_nmethods_not_entrant(); 3781 3782 // From now on we know that the dependency information is complete 3783 JvmtiExport::set_all_dependencies_are_recorded(true); 3784 } 3785 } 3786 3787 void VM_RedefineClasses::compute_added_deleted_matching_methods() { 3788 Method* old_method; 3789 Method* new_method; 3790 3791 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 3792 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 3793 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length()); 3794 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 3795 3796 _matching_methods_length = 0; 3797 _deleted_methods_length = 0; 3798 _added_methods_length = 0; 3799 3800 int nj = 0; 3801 int oj = 0; 3802 while (true) { 3803 if (oj >= _old_methods->length()) { 3804 if (nj >= _new_methods->length()) { 3805 break; // we've looked at everything, done 3806 } 3807 // New method at the end 3808 new_method = _new_methods->at(nj); 3809 _added_methods[_added_methods_length++] = new_method; 3810 ++nj; 3811 } else if (nj >= _new_methods->length()) { 3812 // Old method, at the end, is deleted 3813 old_method = _old_methods->at(oj); 3814 _deleted_methods[_deleted_methods_length++] = old_method; 3815 ++oj; 3816 } else { 3817 old_method = _old_methods->at(oj); 3818 new_method = _new_methods->at(nj); 3819 if (old_method->name() == new_method->name()) { 3820 if (old_method->signature() == new_method->signature()) { 3821 _matching_old_methods[_matching_methods_length ] = old_method; 3822 _matching_new_methods[_matching_methods_length++] = new_method; 3823 ++nj; 3824 ++oj; 3825 } else { 3826 // added overloaded have already been moved to the end, 3827 // so this is a deleted overloaded method 3828 _deleted_methods[_deleted_methods_length++] = old_method; 3829 ++oj; 3830 } 3831 } else { // names don't match 3832 if (old_method->name()->fast_compare(new_method->name()) > 0) { 3833 // new method 3834 _added_methods[_added_methods_length++] = new_method; 3835 ++nj; 3836 } else { 3837 // deleted method 3838 _deleted_methods[_deleted_methods_length++] = old_method; 3839 ++oj; 3840 } 3841 } 3842 } 3843 } 3844 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity"); 3845 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity"); 3846 } 3847 3848 3849 void VM_RedefineClasses::swap_annotations(instanceKlassHandle the_class, 3850 instanceKlassHandle scratch_class) { 3851 // Swap annotation fields values 3852 Annotations* old_annotations = the_class->annotations(); 3853 the_class->set_annotations(scratch_class->annotations()); 3854 scratch_class->set_annotations(old_annotations); 3855 } 3856 3857 3858 // Install the redefinition of a class: 3859 // - house keeping (flushing breakpoints and caches, deoptimizing 3860 // dependent compiled code) 3861 // - replacing parts in the_class with parts from scratch_class 3862 // - adding a weak reference to track the obsolete but interesting 3863 // parts of the_class 3864 // - adjusting constant pool caches and vtables in other classes 3865 // that refer to methods in the_class. These adjustments use the 3866 // ClassLoaderDataGraph::classes_do() facility which only allows 3867 // a helper method to be specified. The interesting parameters 3868 // that we would like to pass to the helper method are saved in 3869 // static global fields in the VM operation. 3870 void VM_RedefineClasses::redefine_single_class(jclass the_jclass, 3871 Klass* scratch_class_oop, TRAPS) { 3872 3873 HandleMark hm(THREAD); // make sure handles from this call are freed 3874 RC_TIMER_START(_timer_rsc_phase1); 3875 3876 instanceKlassHandle scratch_class(scratch_class_oop); 3877 3878 oop the_class_mirror = JNIHandles::resolve_non_null(the_jclass); 3879 Klass* the_class_oop = java_lang_Class::as_Klass(the_class_mirror); 3880 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop); 3881 3882 // Remove all breakpoints in methods of this class 3883 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints(); 3884 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class_oop); 3885 3886 // Deoptimize all compiled code that depends on this class 3887 flush_dependent_code(the_class, THREAD); 3888 3889 _old_methods = the_class->methods(); 3890 _new_methods = scratch_class->methods(); 3891 _the_class_oop = the_class_oop; 3892 compute_added_deleted_matching_methods(); 3893 update_jmethod_ids(); 3894 3895 // Attach new constant pool to the original klass. The original 3896 // klass still refers to the old constant pool (for now). 3897 scratch_class->constants()->set_pool_holder(the_class()); 3898 3899 #if 0 3900 // In theory, with constant pool merging in place we should be able 3901 // to save space by using the new, merged constant pool in place of 3902 // the old constant pool(s). By "pool(s)" I mean the constant pool in 3903 // the klass version we are replacing now and any constant pool(s) in 3904 // previous versions of klass. Nice theory, doesn't work in practice. 3905 // When this code is enabled, even simple programs throw NullPointer 3906 // exceptions. I'm guessing that this is caused by some constant pool 3907 // cache difference between the new, merged constant pool and the 3908 // constant pool that was just being used by the klass. I'm keeping 3909 // this code around to archive the idea, but the code has to remain 3910 // disabled for now. 3911 3912 // Attach each old method to the new constant pool. This can be 3913 // done here since we are past the bytecode verification and 3914 // constant pool optimization phases. 3915 for (int i = _old_methods->length() - 1; i >= 0; i--) { 3916 Method* method = _old_methods->at(i); 3917 method->set_constants(scratch_class->constants()); 3918 } 3919 3920 { 3921 // walk all previous versions of the klass 3922 InstanceKlass *ik = (InstanceKlass *)the_class(); 3923 PreviousVersionWalker pvw(ik); 3924 instanceKlassHandle ikh; 3925 do { 3926 ikh = pvw.next_previous_version(); 3927 if (!ikh.is_null()) { 3928 ik = ikh(); 3929 3930 // attach previous version of klass to the new constant pool 3931 ik->set_constants(scratch_class->constants()); 3932 3933 // Attach each method in the previous version of klass to the 3934 // new constant pool 3935 Array<Method*>* prev_methods = ik->methods(); 3936 for (int i = prev_methods->length() - 1; i >= 0; i--) { 3937 Method* method = prev_methods->at(i); 3938 method->set_constants(scratch_class->constants()); 3939 } 3940 } 3941 } while (!ikh.is_null()); 3942 } 3943 #endif 3944 3945 // Replace methods and constantpool 3946 the_class->set_methods(_new_methods); 3947 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods, 3948 // and to be able to undo operation easily. 3949 3950 ConstantPool* old_constants = the_class->constants(); 3951 the_class->set_constants(scratch_class->constants()); 3952 scratch_class->set_constants(old_constants); // See the previous comment. 3953 #if 0 3954 // We are swapping the guts of "the new class" with the guts of "the 3955 // class". Since the old constant pool has just been attached to "the 3956 // new class", it seems logical to set the pool holder in the old 3957 // constant pool also. However, doing this will change the observable 3958 // class hierarchy for any old methods that are still executing. A 3959 // method can query the identity of its "holder" and this query uses 3960 // the method's constant pool link to find the holder. The change in 3961 // holding class from "the class" to "the new class" can confuse 3962 // things. 3963 // 3964 // Setting the old constant pool's holder will also cause 3965 // verification done during vtable initialization below to fail. 3966 // During vtable initialization, the vtable's class is verified to be 3967 // a subtype of the method's holder. The vtable's class is "the 3968 // class" and the method's holder is gotten from the constant pool 3969 // link in the method itself. For "the class"'s directly implemented 3970 // methods, the method holder is "the class" itself (as gotten from 3971 // the new constant pool). The check works fine in this case. The 3972 // check also works fine for methods inherited from super classes. 3973 // 3974 // Miranda methods are a little more complicated. A miranda method is 3975 // provided by an interface when the class implementing the interface 3976 // does not provide its own method. These interfaces are implemented 3977 // internally as an InstanceKlass. These special instanceKlasses 3978 // share the constant pool of the class that "implements" the 3979 // interface. By sharing the constant pool, the method holder of a 3980 // miranda method is the class that "implements" the interface. In a 3981 // non-redefine situation, the subtype check works fine. However, if 3982 // the old constant pool's pool holder is modified, then the check 3983 // fails because there is no class hierarchy relationship between the 3984 // vtable's class and "the new class". 3985 3986 old_constants->set_pool_holder(scratch_class()); 3987 #endif 3988 3989 // track number of methods that are EMCP for add_previous_version() call below 3990 int emcp_method_count = check_methods_and_mark_as_obsolete(); 3991 transfer_old_native_function_registrations(the_class); 3992 3993 // The class file bytes from before any retransformable agents mucked 3994 // with them was cached on the scratch class, move to the_class. 3995 // Note: we still want to do this if nothing needed caching since it 3996 // should get cleared in the_class too. 3997 if (the_class->get_cached_class_file_bytes() == 0) { 3998 // the_class doesn't have a cache yet so copy it 3999 the_class->set_cached_class_file(scratch_class->get_cached_class_file()); 4000 } 4001 #ifndef PRODUCT 4002 else { 4003 assert(the_class->get_cached_class_file_bytes() == 4004 scratch_class->get_cached_class_file_bytes(), "cache ptrs must match"); 4005 assert(the_class->get_cached_class_file_len() == 4006 scratch_class->get_cached_class_file_len(), "cache lens must match"); 4007 } 4008 #endif 4009 4010 // NULL out in scratch class to not delete twice. The class to be redefined 4011 // always owns these bytes. 4012 scratch_class->set_cached_class_file(NULL); 4013 4014 // Replace inner_classes 4015 Array<u2>* old_inner_classes = the_class->inner_classes(); 4016 the_class->set_inner_classes(scratch_class->inner_classes()); 4017 scratch_class->set_inner_classes(old_inner_classes); 4018 4019 // Initialize the vtable and interface table after 4020 // methods have been rewritten 4021 { 4022 ResourceMark rm(THREAD); 4023 // no exception should happen here since we explicitly 4024 // do not check loader constraints. 4025 // compare_and_normalize_class_versions has already checked: 4026 // - classloaders unchanged, signatures unchanged 4027 // - all instanceKlasses for redefined classes reused & contents updated 4028 the_class->vtable()->initialize_vtable(false, THREAD); 4029 the_class->itable()->initialize_itable(false, THREAD); 4030 assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())), "redefine exception"); 4031 } 4032 4033 // Leave arrays of jmethodIDs and itable index cache unchanged 4034 4035 // Copy the "source file name" attribute from new class version 4036 the_class->set_source_file_name_index( 4037 scratch_class->source_file_name_index()); 4038 4039 // Copy the "source debug extension" attribute from new class version 4040 the_class->set_source_debug_extension( 4041 scratch_class->source_debug_extension(), 4042 scratch_class->source_debug_extension() == NULL ? 0 : 4043 (int)strlen(scratch_class->source_debug_extension())); 4044 4045 // Use of javac -g could be different in the old and the new 4046 if (scratch_class->access_flags().has_localvariable_table() != 4047 the_class->access_flags().has_localvariable_table()) { 4048 4049 AccessFlags flags = the_class->access_flags(); 4050 if (scratch_class->access_flags().has_localvariable_table()) { 4051 flags.set_has_localvariable_table(); 4052 } else { 4053 flags.clear_has_localvariable_table(); 4054 } 4055 the_class->set_access_flags(flags); 4056 } 4057 4058 swap_annotations(the_class, scratch_class); 4059 4060 // Replace minor version number of class file 4061 u2 old_minor_version = the_class->minor_version(); 4062 the_class->set_minor_version(scratch_class->minor_version()); 4063 scratch_class->set_minor_version(old_minor_version); 4064 4065 // Replace major version number of class file 4066 u2 old_major_version = the_class->major_version(); 4067 the_class->set_major_version(scratch_class->major_version()); 4068 scratch_class->set_major_version(old_major_version); 4069 4070 // Replace CP indexes for class and name+type of enclosing method 4071 u2 old_class_idx = the_class->enclosing_method_class_index(); 4072 u2 old_method_idx = the_class->enclosing_method_method_index(); 4073 the_class->set_enclosing_method_indices( 4074 scratch_class->enclosing_method_class_index(), 4075 scratch_class->enclosing_method_method_index()); 4076 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx); 4077 4078 the_class->set_has_been_redefined(); 4079 4080 // keep track of previous versions of this class 4081 the_class->add_previous_version(scratch_class, emcp_method_count); 4082 4083 RC_TIMER_STOP(_timer_rsc_phase1); 4084 RC_TIMER_START(_timer_rsc_phase2); 4085 4086 // Adjust constantpool caches and vtables for all classes 4087 // that reference methods of the evolved class. 4088 AdjustCpoolCacheAndVtable adjust_cpool_cache_and_vtable(THREAD); 4089 ClassLoaderDataGraph::classes_do(&adjust_cpool_cache_and_vtable); 4090 4091 // JSR-292 support 4092 MemberNameTable* mnt = the_class->member_names(); 4093 if (mnt != NULL) { 4094 bool trace_name_printed = false; 4095 mnt->adjust_method_entries(_matching_old_methods, 4096 _matching_new_methods, 4097 _matching_methods_length, 4098 &trace_name_printed); 4099 } 4100 4101 // Fix Resolution Error table also to remove old constant pools 4102 SystemDictionary::delete_resolution_error(old_constants); 4103 4104 if (the_class->oop_map_cache() != NULL) { 4105 // Flush references to any obsolete methods from the oop map cache 4106 // so that obsolete methods are not pinned. 4107 the_class->oop_map_cache()->flush_obsolete_entries(); 4108 } 4109 4110 // increment the classRedefinedCount field in the_class and in any 4111 // direct and indirect subclasses of the_class 4112 increment_class_counter((InstanceKlass *)the_class(), THREAD); 4113 4114 // RC_TRACE macro has an embedded ResourceMark 4115 RC_TRACE_WITH_THREAD(0x00000001, THREAD, 4116 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)", 4117 the_class->external_name(), 4118 java_lang_Class::classRedefinedCount(the_class_mirror), 4119 os::available_memory() >> 10)); 4120 4121 RC_TIMER_STOP(_timer_rsc_phase2); 4122 } // end redefine_single_class() 4123 4124 4125 // Increment the classRedefinedCount field in the specific InstanceKlass 4126 // and in all direct and indirect subclasses. 4127 void VM_RedefineClasses::increment_class_counter(InstanceKlass *ik, TRAPS) { 4128 oop class_mirror = ik->java_mirror(); 4129 Klass* class_oop = java_lang_Class::as_Klass(class_mirror); 4130 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1; 4131 java_lang_Class::set_classRedefinedCount(class_mirror, new_count); 4132 4133 if (class_oop != _the_class_oop) { 4134 // _the_class_oop count is printed at end of redefine_single_class() 4135 RC_TRACE_WITH_THREAD(0x00000008, THREAD, 4136 ("updated count in subclass=%s to %d", ik->external_name(), new_count)); 4137 } 4138 4139 for (Klass *subk = ik->subklass(); subk != NULL; 4140 subk = subk->next_sibling()) { 4141 if (subk->oop_is_instance()) { 4142 // Only update instanceKlasses 4143 InstanceKlass *subik = (InstanceKlass*)subk; 4144 // recursively do subclasses of the current subclass 4145 increment_class_counter(subik, THREAD); 4146 } 4147 } 4148 } 4149 4150 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) { 4151 bool no_old_methods = true; // be optimistic 4152 4153 // Both array and instance classes have vtables. 4154 // a vtable should never contain old or obsolete methods 4155 ResourceMark rm(_thread); 4156 if (k->vtable_length() > 0 && 4157 !k->vtable()->check_no_old_or_obsolete_entries()) { 4158 if (RC_TRACE_ENABLED(0x00004000)) { 4159 RC_TRACE_WITH_THREAD(0x00004000, _thread, 4160 ("klassVtable::check_no_old_or_obsolete_entries failure" 4161 " -- OLD or OBSOLETE method found -- class: %s", 4162 k->signature_name())); 4163 k->vtable()->dump_vtable(); 4164 } 4165 no_old_methods = false; 4166 } 4167 4168 if (k->oop_is_instance()) { 4169 HandleMark hm(_thread); 4170 InstanceKlass *ik = InstanceKlass::cast(k); 4171 4172 // an itable should never contain old or obsolete methods 4173 if (ik->itable_length() > 0 && 4174 !ik->itable()->check_no_old_or_obsolete_entries()) { 4175 if (RC_TRACE_ENABLED(0x00004000)) { 4176 RC_TRACE_WITH_THREAD(0x00004000, _thread, 4177 ("klassItable::check_no_old_or_obsolete_entries failure" 4178 " -- OLD or OBSOLETE method found -- class: %s", 4179 ik->signature_name())); 4180 ik->itable()->dump_itable(); 4181 } 4182 no_old_methods = false; 4183 } 4184 4185 // the constant pool cache should never contain non-deleted old or obsolete methods 4186 if (ik->constants() != NULL && 4187 ik->constants()->cache() != NULL && 4188 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) { 4189 if (RC_TRACE_ENABLED(0x00004000)) { 4190 RC_TRACE_WITH_THREAD(0x00004000, _thread, 4191 ("cp-cache::check_no_old_or_obsolete_entries failure" 4192 " -- OLD or OBSOLETE method found -- class: %s", 4193 ik->signature_name())); 4194 ik->constants()->cache()->dump_cache(); 4195 } 4196 no_old_methods = false; 4197 } 4198 } 4199 4200 // print and fail guarantee if old methods are found. 4201 if (!no_old_methods) { 4202 if (RC_TRACE_ENABLED(0x00004000)) { 4203 dump_methods(); 4204 } else { 4205 tty->print_cr("INFO: use the '-XX:TraceRedefineClasses=16384' option " 4206 "to see more info about the following guarantee() failure."); 4207 } 4208 guarantee(false, "OLD and/or OBSOLETE method(s) found"); 4209 } 4210 } 4211 4212 4213 void VM_RedefineClasses::dump_methods() { 4214 int j; 4215 RC_TRACE(0x00004000, ("_old_methods --")); 4216 for (j = 0; j < _old_methods->length(); ++j) { 4217 Method* m = _old_methods->at(j); 4218 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index())); 4219 m->access_flags().print_on(tty); 4220 tty->print(" -- "); 4221 m->print_name(tty); 4222 tty->cr(); 4223 } 4224 RC_TRACE(0x00004000, ("_new_methods --")); 4225 for (j = 0; j < _new_methods->length(); ++j) { 4226 Method* m = _new_methods->at(j); 4227 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index())); 4228 m->access_flags().print_on(tty); 4229 tty->print(" -- "); 4230 m->print_name(tty); 4231 tty->cr(); 4232 } 4233 RC_TRACE(0x00004000, ("_matching_(old/new)_methods --")); 4234 for (j = 0; j < _matching_methods_length; ++j) { 4235 Method* m = _matching_old_methods[j]; 4236 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index())); 4237 m->access_flags().print_on(tty); 4238 tty->print(" -- "); 4239 m->print_name(tty); 4240 tty->cr(); 4241 m = _matching_new_methods[j]; 4242 RC_TRACE_NO_CR(0x00004000, (" (%5d) ", m->vtable_index())); 4243 m->access_flags().print_on(tty); 4244 tty->cr(); 4245 } 4246 RC_TRACE(0x00004000, ("_deleted_methods --")); 4247 for (j = 0; j < _deleted_methods_length; ++j) { 4248 Method* m = _deleted_methods[j]; 4249 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index())); 4250 m->access_flags().print_on(tty); 4251 tty->print(" -- "); 4252 m->print_name(tty); 4253 tty->cr(); 4254 } 4255 RC_TRACE(0x00004000, ("_added_methods --")); 4256 for (j = 0; j < _added_methods_length; ++j) { 4257 Method* m = _added_methods[j]; 4258 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index())); 4259 m->access_flags().print_on(tty); 4260 tty->print(" -- "); 4261 m->print_name(tty); 4262 tty->cr(); 4263 } 4264 }