1 /* 2 * Copyright (c) 2003, 2013, 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 47 Array<Method*>* VM_RedefineClasses::_old_methods = NULL; 48 Array<Method*>* VM_RedefineClasses::_new_methods = NULL; 49 Method** VM_RedefineClasses::_matching_old_methods = NULL; 50 Method** VM_RedefineClasses::_matching_new_methods = NULL; 51 Method** VM_RedefineClasses::_deleted_methods = NULL; 52 Method** VM_RedefineClasses::_added_methods = NULL; 53 int VM_RedefineClasses::_matching_methods_length = 0; 54 int VM_RedefineClasses::_deleted_methods_length = 0; 55 int VM_RedefineClasses::_added_methods_length = 0; 56 Klass* VM_RedefineClasses::_the_class_oop = NULL; 57 58 59 VM_RedefineClasses::VM_RedefineClasses(jint class_count, 60 const jvmtiClassDefinition *class_defs, 61 JvmtiClassLoadKind class_load_kind) { 62 _class_count = class_count; 63 _class_defs = class_defs; 64 _class_load_kind = class_load_kind; 65 _res = JVMTI_ERROR_NONE; 66 } 67 68 bool VM_RedefineClasses::doit_prologue() { 69 if (_class_count == 0) { 70 _res = JVMTI_ERROR_NONE; 71 return false; 72 } 73 if (_class_defs == NULL) { 74 _res = JVMTI_ERROR_NULL_POINTER; 75 return false; 76 } 77 for (int i = 0; i < _class_count; i++) { 78 if (_class_defs[i].klass == NULL) { 79 _res = JVMTI_ERROR_INVALID_CLASS; 80 return false; 81 } 82 if (_class_defs[i].class_byte_count == 0) { 83 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT; 84 return false; 85 } 86 if (_class_defs[i].class_bytes == NULL) { 87 _res = JVMTI_ERROR_NULL_POINTER; 88 return false; 89 } 90 } 91 92 // Start timer after all the sanity checks; not quite accurate, but 93 // better than adding a bunch of stop() calls. 94 RC_TIMER_START(_timer_vm_op_prologue); 95 96 // We first load new class versions in the prologue, because somewhere down the 97 // call chain it is required that the current thread is a Java thread. 98 _res = load_new_class_versions(Thread::current()); 99 if (_res != JVMTI_ERROR_NONE) { 100 // free any successfully created classes, since none are redefined 101 for (int i = 0; i < _class_count; i++) { 102 if (_scratch_classes[i] != NULL) { 103 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data(); 104 // Free the memory for this class at class unloading time. Not before 105 // because CMS might think this is still live. 106 cld->add_to_deallocate_list((InstanceKlass*)_scratch_classes[i]); 107 } 108 } 109 // Free os::malloc allocated memory in load_new_class_version. 110 os::free(_scratch_classes); 111 RC_TIMER_STOP(_timer_vm_op_prologue); 112 return false; 113 } 114 115 RC_TIMER_STOP(_timer_vm_op_prologue); 116 return true; 117 } 118 119 void VM_RedefineClasses::doit() { 120 Thread *thread = Thread::current(); 121 122 if (UseSharedSpaces) { 123 // Sharing is enabled so we remap the shared readonly space to 124 // shared readwrite, private just in case we need to redefine 125 // a shared class. We do the remap during the doit() phase of 126 // the safepoint to be safer. 127 if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) { 128 RC_TRACE_WITH_THREAD(0x00000001, thread, 129 ("failed to remap shared readonly space to readwrite, private")); 130 _res = JVMTI_ERROR_INTERNAL; 131 return; 132 } 133 } 134 135 // Mark methods seen on stack and everywhere else so old methods are not 136 // cleaned up if they're on the stack. 137 MetadataOnStackMark md_on_stack; 138 HandleMark hm(thread); // make sure any handles created are deleted 139 // before the stack walk again. 140 141 for (int i = 0; i < _class_count; i++) { 142 redefine_single_class(_class_defs[i].klass, _scratch_classes[i], thread); 143 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data(); 144 // Free the memory for this class at class unloading time. Not before 145 // because CMS might think this is still live. 146 cld->add_to_deallocate_list((InstanceKlass*)_scratch_classes[i]); 147 _scratch_classes[i] = NULL; 148 } 149 150 // Disable any dependent concurrent compilations 151 SystemDictionary::notice_modification(); 152 153 // Set flag indicating that some invariants are no longer true. 154 // See jvmtiExport.hpp for detailed explanation. 155 JvmtiExport::set_has_redefined_a_class(); 156 157 // check_class() is optionally called for product bits, but is 158 // always called for non-product bits. 159 #ifdef PRODUCT 160 if (RC_TRACE_ENABLED(0x00004000)) { 161 #endif 162 RC_TRACE_WITH_THREAD(0x00004000, thread, ("calling check_class")); 163 CheckClass check_class(thread); 164 ClassLoaderDataGraph::classes_do(&check_class); 165 #ifdef PRODUCT 166 } 167 #endif 168 } 169 170 void VM_RedefineClasses::doit_epilogue() { 171 // Free os::malloc allocated memory. 172 os::free(_scratch_classes); 173 174 if (RC_TRACE_ENABLED(0x00000004)) { 175 // Used to have separate timers for "doit" and "all", but the timer 176 // overhead skewed the measurements. 177 jlong doit_time = _timer_rsc_phase1.milliseconds() + 178 _timer_rsc_phase2.milliseconds(); 179 jlong all_time = _timer_vm_op_prologue.milliseconds() + doit_time; 180 181 RC_TRACE(0x00000004, ("vm_op: all=" UINT64_FORMAT 182 " prologue=" UINT64_FORMAT " doit=" UINT64_FORMAT, all_time, 183 _timer_vm_op_prologue.milliseconds(), doit_time)); 184 RC_TRACE(0x00000004, 185 ("redefine_single_class: phase1=" UINT64_FORMAT " phase2=" UINT64_FORMAT, 186 _timer_rsc_phase1.milliseconds(), _timer_rsc_phase2.milliseconds())); 187 } 188 } 189 190 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) { 191 // classes for primitives cannot be redefined 192 if (java_lang_Class::is_primitive(klass_mirror)) { 193 return false; 194 } 195 Klass* the_class_oop = java_lang_Class::as_Klass(klass_mirror); 196 // classes for arrays cannot be redefined 197 if (the_class_oop == NULL || !the_class_oop->oop_is_instance()) { 198 return false; 199 } 200 return true; 201 } 202 203 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p 204 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For 205 // direct CP entries, there is just the current entry to append. For 206 // indirect and double-indirect CP entries, there are zero or more 207 // referenced CP entries along with the current entry to append. 208 // Indirect and double-indirect CP entries are handled by recursive 209 // calls to append_entry() as needed. The referenced CP entries are 210 // always appended to *merge_cp_p before the referee CP entry. These 211 // referenced CP entries may already exist in *merge_cp_p in which case 212 // there is nothing extra to append and only the current entry is 213 // appended. 214 void VM_RedefineClasses::append_entry(constantPoolHandle scratch_cp, 215 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, 216 TRAPS) { 217 218 // append is different depending on entry tag type 219 switch (scratch_cp->tag_at(scratch_i).value()) { 220 221 // The old verifier is implemented outside the VM. It loads classes, 222 // but does not resolve constant pool entries directly so we never 223 // see Class entries here with the old verifier. Similarly the old 224 // verifier does not like Class entries in the input constant pool. 225 // The split-verifier is implemented in the VM so it can optionally 226 // and directly resolve constant pool entries to load classes. The 227 // split-verifier can accept either Class entries or UnresolvedClass 228 // entries in the input constant pool. We revert the appended copy 229 // back to UnresolvedClass so that either verifier will be happy 230 // with the constant pool entry. 231 case JVM_CONSTANT_Class: 232 { 233 // revert the copy to JVM_CONSTANT_UnresolvedClass 234 (*merge_cp_p)->unresolved_klass_at_put(*merge_cp_length_p, 235 scratch_cp->klass_name_at(scratch_i)); 236 237 if (scratch_i != *merge_cp_length_p) { 238 // The new entry in *merge_cp_p is at a different index than 239 // the new entry in scratch_cp so we need to map the index values. 240 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 241 } 242 (*merge_cp_length_p)++; 243 } break; 244 245 // these are direct CP entries so they can be directly appended, 246 // but double and long take two constant pool entries 247 case JVM_CONSTANT_Double: // fall through 248 case JVM_CONSTANT_Long: 249 { 250 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p, 251 THREAD); 252 253 if (scratch_i != *merge_cp_length_p) { 254 // The new entry in *merge_cp_p is at a different index than 255 // the new entry in scratch_cp so we need to map the index values. 256 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 257 } 258 (*merge_cp_length_p) += 2; 259 } break; 260 261 // these are direct CP entries so they can be directly appended 262 case JVM_CONSTANT_Float: // fall through 263 case JVM_CONSTANT_Integer: // fall through 264 case JVM_CONSTANT_Utf8: // fall through 265 266 // This was an indirect CP entry, but it has been changed into 267 // Symbol*s so this entry can be directly appended. 268 case JVM_CONSTANT_String: // fall through 269 270 // These were indirect CP entries, but they have been changed into 271 // Symbol*s so these entries can be directly appended. 272 case JVM_CONSTANT_UnresolvedClass: // fall through 273 { 274 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p, 275 THREAD); 276 277 if (scratch_i != *merge_cp_length_p) { 278 // The new entry in *merge_cp_p is at a different index than 279 // the new entry in scratch_cp so we need to map the index values. 280 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 281 } 282 (*merge_cp_length_p)++; 283 } break; 284 285 // this is an indirect CP entry so it needs special handling 286 case JVM_CONSTANT_NameAndType: 287 { 288 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i); 289 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p, 290 merge_cp_length_p, THREAD); 291 292 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i); 293 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i, 294 merge_cp_p, merge_cp_length_p, 295 THREAD); 296 297 // If the referenced entries already exist in *merge_cp_p, then 298 // both new_name_ref_i and new_signature_ref_i will both be 0. 299 // In that case, all we are appending is the current entry. 300 if (new_name_ref_i != name_ref_i) { 301 RC_TRACE(0x00080000, 302 ("NameAndType entry@%d name_ref_index change: %d to %d", 303 *merge_cp_length_p, name_ref_i, new_name_ref_i)); 304 } 305 if (new_signature_ref_i != signature_ref_i) { 306 RC_TRACE(0x00080000, 307 ("NameAndType entry@%d signature_ref_index change: %d to %d", 308 *merge_cp_length_p, signature_ref_i, new_signature_ref_i)); 309 } 310 311 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p, 312 new_name_ref_i, new_signature_ref_i); 313 if (scratch_i != *merge_cp_length_p) { 314 // The new entry in *merge_cp_p is at a different index than 315 // the new entry in scratch_cp so we need to map the index values. 316 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 317 } 318 (*merge_cp_length_p)++; 319 } break; 320 321 // this is a double-indirect CP entry so it needs special handling 322 case JVM_CONSTANT_Fieldref: // fall through 323 case JVM_CONSTANT_InterfaceMethodref: // fall through 324 case JVM_CONSTANT_Methodref: 325 { 326 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i); 327 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i, 328 merge_cp_p, merge_cp_length_p, THREAD); 329 330 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i); 331 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i, 332 merge_cp_p, merge_cp_length_p, THREAD); 333 334 const char *entry_name; 335 switch (scratch_cp->tag_at(scratch_i).value()) { 336 case JVM_CONSTANT_Fieldref: 337 entry_name = "Fieldref"; 338 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i, 339 new_name_and_type_ref_i); 340 break; 341 case JVM_CONSTANT_InterfaceMethodref: 342 entry_name = "IFMethodref"; 343 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p, 344 new_klass_ref_i, new_name_and_type_ref_i); 345 break; 346 case JVM_CONSTANT_Methodref: 347 entry_name = "Methodref"; 348 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i, 349 new_name_and_type_ref_i); 350 break; 351 default: 352 guarantee(false, "bad switch"); 353 break; 354 } 355 356 if (klass_ref_i != new_klass_ref_i) { 357 RC_TRACE(0x00080000, ("%s entry@%d class_index changed: %d to %d", 358 entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i)); 359 } 360 if (name_and_type_ref_i != new_name_and_type_ref_i) { 361 RC_TRACE(0x00080000, 362 ("%s entry@%d name_and_type_index changed: %d to %d", 363 entry_name, *merge_cp_length_p, name_and_type_ref_i, 364 new_name_and_type_ref_i)); 365 } 366 367 if (scratch_i != *merge_cp_length_p) { 368 // The new entry in *merge_cp_p is at a different index than 369 // the new entry in scratch_cp so we need to map the index values. 370 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 371 } 372 (*merge_cp_length_p)++; 373 } break; 374 375 // this is an indirect CP entry so it needs special handling 376 case JVM_CONSTANT_MethodType: 377 { 378 int ref_i = scratch_cp->method_type_index_at(scratch_i); 379 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p, 380 merge_cp_length_p, THREAD); 381 if (new_ref_i != ref_i) { 382 RC_TRACE(0x00080000, 383 ("MethodType entry@%d ref_index change: %d to %d", 384 *merge_cp_length_p, ref_i, new_ref_i)); 385 } 386 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i); 387 if (scratch_i != *merge_cp_length_p) { 388 // The new entry in *merge_cp_p is at a different index than 389 // the new entry in scratch_cp so we need to map the index values. 390 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 391 } 392 (*merge_cp_length_p)++; 393 } break; 394 395 // this is an indirect CP entry so it needs special handling 396 case JVM_CONSTANT_MethodHandle: 397 { 398 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i); 399 int ref_i = scratch_cp->method_handle_index_at(scratch_i); 400 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p, 401 merge_cp_length_p, THREAD); 402 if (new_ref_i != ref_i) { 403 RC_TRACE(0x00080000, 404 ("MethodHandle entry@%d ref_index change: %d to %d", 405 *merge_cp_length_p, ref_i, new_ref_i)); 406 } 407 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i); 408 if (scratch_i != *merge_cp_length_p) { 409 // The new entry in *merge_cp_p is at a different index than 410 // the new entry in scratch_cp so we need to map the index values. 411 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 412 } 413 (*merge_cp_length_p)++; 414 } break; 415 416 // this is an indirect CP entry so it needs special handling 417 case JVM_CONSTANT_InvokeDynamic: 418 { 419 // Index of the bootstrap specifier in the operands array 420 int old_bs_i = scratch_cp->invoke_dynamic_bootstrap_specifier_index(scratch_i); 421 int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p, 422 merge_cp_length_p, THREAD); 423 // The bootstrap method NameAndType_info index 424 int old_ref_i = scratch_cp->invoke_dynamic_name_and_type_ref_index_at(scratch_i); 425 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p, 426 merge_cp_length_p, THREAD); 427 if (new_bs_i != old_bs_i) { 428 RC_TRACE(0x00080000, 429 ("InvokeDynamic entry@%d bootstrap_method_attr_index change: %d to %d", 430 *merge_cp_length_p, old_bs_i, new_bs_i)); 431 } 432 if (new_ref_i != old_ref_i) { 433 RC_TRACE(0x00080000, 434 ("InvokeDynamic entry@%d name_and_type_index change: %d to %d", 435 *merge_cp_length_p, old_ref_i, new_ref_i)); 436 } 437 438 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i); 439 if (scratch_i != *merge_cp_length_p) { 440 // The new entry in *merge_cp_p is at a different index than 441 // the new entry in scratch_cp so we need to map the index values. 442 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 443 } 444 (*merge_cp_length_p)++; 445 } break; 446 447 // At this stage, Class or UnresolvedClass could be here, but not 448 // ClassIndex 449 case JVM_CONSTANT_ClassIndex: // fall through 450 451 // Invalid is used as the tag for the second constant pool entry 452 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should 453 // not be seen by itself. 454 case JVM_CONSTANT_Invalid: // fall through 455 456 // At this stage, String could be here, but not StringIndex 457 case JVM_CONSTANT_StringIndex: // fall through 458 459 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be 460 // here 461 case JVM_CONSTANT_UnresolvedClassInError: // fall through 462 463 default: 464 { 465 // leave a breadcrumb 466 jbyte bad_value = scratch_cp->tag_at(scratch_i).value(); 467 ShouldNotReachHere(); 468 } break; 469 } // end switch tag value 470 } // end append_entry() 471 472 473 int VM_RedefineClasses::find_or_append_indirect_entry(constantPoolHandle scratch_cp, 474 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) { 475 476 int new_ref_i = ref_i; 477 bool match = (ref_i < *merge_cp_length_p) && 478 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i, THREAD); 479 480 if (!match) { 481 // forward reference in *merge_cp_p or not a direct match 482 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p, THREAD); 483 if (found_i != 0) { 484 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree"); 485 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry. 486 new_ref_i = found_i; 487 map_index(scratch_cp, ref_i, found_i); 488 } else { 489 // no match found so we have to append this entry to *merge_cp_p 490 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p, THREAD); 491 // The above call to append_entry() can only append one entry 492 // so the post call query of *merge_cp_length_p is only for 493 // the sake of consistency. 494 new_ref_i = *merge_cp_length_p - 1; 495 } 496 } 497 498 return new_ref_i; 499 } // end find_or_append_indirect_entry() 500 501 502 // Append a bootstrap specifier into the merge_cp operands that is semantically equal 503 // to the scratch_cp operands bootstrap specifier passed by the old_bs_i index. 504 // Recursively append new merge_cp entries referenced by the new bootstrap specifier. 505 void VM_RedefineClasses::append_operand(constantPoolHandle scratch_cp, int old_bs_i, 506 constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) { 507 508 int old_ref_i = scratch_cp->operand_bootstrap_method_ref_index_at(old_bs_i); 509 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p, 510 merge_cp_length_p, THREAD); 511 if (new_ref_i != old_ref_i) { 512 RC_TRACE(0x00080000, 513 ("operands entry@%d bootstrap method ref_index change: %d to %d", 514 _operands_cur_length, old_ref_i, new_ref_i)); 515 } 516 517 Array<u2>* merge_ops = (*merge_cp_p)->operands(); 518 int new_bs_i = _operands_cur_length; 519 // We have _operands_cur_length == 0 when the merge_cp operands is empty yet. 520 // However, the operand_offset_at(0) was set in the extend_operands() call. 521 int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0) 522 : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1); 523 int argc = scratch_cp->operand_argument_count_at(old_bs_i); 524 525 ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base); 526 merge_ops->at_put(new_base++, new_ref_i); 527 merge_ops->at_put(new_base++, argc); 528 529 for (int i = 0; i < argc; i++) { 530 int old_arg_ref_i = scratch_cp->operand_argument_index_at(old_bs_i, i); 531 int new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p, 532 merge_cp_length_p, THREAD); 533 merge_ops->at_put(new_base++, new_arg_ref_i); 534 if (new_arg_ref_i != old_arg_ref_i) { 535 RC_TRACE(0x00080000, 536 ("operands entry@%d bootstrap method argument ref_index change: %d to %d", 537 _operands_cur_length, old_arg_ref_i, new_arg_ref_i)); 538 } 539 } 540 if (old_bs_i != _operands_cur_length) { 541 // The bootstrap specifier in *merge_cp_p is at a different index than 542 // that in scratch_cp so we need to map the index values. 543 map_operand_index(old_bs_i, new_bs_i); 544 } 545 _operands_cur_length++; 546 } // end append_operand() 547 548 549 int VM_RedefineClasses::find_or_append_operand(constantPoolHandle scratch_cp, 550 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) { 551 552 int new_bs_i = old_bs_i; // bootstrap specifier index 553 bool match = (old_bs_i < _operands_cur_length) && 554 scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i, THREAD); 555 556 if (!match) { 557 // forward reference in *merge_cp_p or not a direct match 558 int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p, 559 _operands_cur_length, THREAD); 560 if (found_i != -1) { 561 guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree"); 562 // found a matching operand somewhere else in *merge_cp_p so just need a mapping 563 new_bs_i = found_i; 564 map_operand_index(old_bs_i, found_i); 565 } else { 566 // no match found so we have to append this bootstrap specifier to *merge_cp_p 567 append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p, THREAD); 568 new_bs_i = _operands_cur_length - 1; 569 } 570 } 571 return new_bs_i; 572 } // end find_or_append_operand() 573 574 575 void VM_RedefineClasses::finalize_operands_merge(constantPoolHandle merge_cp, TRAPS) { 576 if (merge_cp->operands() == NULL) { 577 return; 578 } 579 // Shrink the merge_cp operands 580 merge_cp->shrink_operands(_operands_cur_length, CHECK); 581 582 if (RC_TRACE_ENABLED(0x00040000)) { 583 // don't want to loop unless we are tracing 584 int count = 0; 585 for (int i = 1; i < _operands_index_map_p->length(); i++) { 586 int value = _operands_index_map_p->at(i); 587 if (value != -1) { 588 RC_TRACE_WITH_THREAD(0x00040000, THREAD, 589 ("operands_index_map[%d]: old=%d new=%d", count, i, value)); 590 count++; 591 } 592 } 593 } 594 // Clean-up 595 _operands_index_map_p = NULL; 596 _operands_cur_length = 0; 597 _operands_index_map_count = 0; 598 } // end finalize_operands_merge() 599 600 601 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions( 602 instanceKlassHandle the_class, 603 instanceKlassHandle scratch_class) { 604 int i; 605 606 // Check superclasses, or rather their names, since superclasses themselves can be 607 // requested to replace. 608 // Check for NULL superclass first since this might be java.lang.Object 609 if (the_class->super() != scratch_class->super() && 610 (the_class->super() == NULL || scratch_class->super() == NULL || 611 the_class->super()->name() != 612 scratch_class->super()->name())) { 613 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 614 } 615 616 // Check if the number, names and order of directly implemented interfaces are the same. 617 // I think in principle we should just check if the sets of names of directly implemented 618 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the 619 // .java file, also changes in .class file) should not matter. However, comparing sets is 620 // technically a bit more difficult, and, more importantly, I am not sure at present that the 621 // order of interfaces does not matter on the implementation level, i.e. that the VM does not 622 // rely on it somewhere. 623 Array<Klass*>* k_interfaces = the_class->local_interfaces(); 624 Array<Klass*>* k_new_interfaces = scratch_class->local_interfaces(); 625 int n_intfs = k_interfaces->length(); 626 if (n_intfs != k_new_interfaces->length()) { 627 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 628 } 629 for (i = 0; i < n_intfs; i++) { 630 if (k_interfaces->at(i)->name() != 631 k_new_interfaces->at(i)->name()) { 632 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 633 } 634 } 635 636 // Check whether class is in the error init state. 637 if (the_class->is_in_error_state()) { 638 // TBD #5057930: special error code is needed in 1.6 639 return JVMTI_ERROR_INVALID_CLASS; 640 } 641 642 // Check whether class modifiers are the same. 643 jushort old_flags = (jushort) the_class->access_flags().get_flags(); 644 jushort new_flags = (jushort) scratch_class->access_flags().get_flags(); 645 if (old_flags != new_flags) { 646 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED; 647 } 648 649 // Check if the number, names, types and order of fields declared in these classes 650 // are the same. 651 JavaFieldStream old_fs(the_class); 652 JavaFieldStream new_fs(scratch_class); 653 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) { 654 // access 655 old_flags = old_fs.access_flags().as_short(); 656 new_flags = new_fs.access_flags().as_short(); 657 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) { 658 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 659 } 660 // offset 661 if (old_fs.offset() != new_fs.offset()) { 662 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 663 } 664 // name and signature 665 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index()); 666 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index()); 667 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index()); 668 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index()); 669 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) { 670 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 671 } 672 } 673 674 // If both streams aren't done then we have a differing number of 675 // fields. 676 if (!old_fs.done() || !new_fs.done()) { 677 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 678 } 679 680 // Do a parallel walk through the old and new methods. Detect 681 // cases where they match (exist in both), have been added in 682 // the new methods, or have been deleted (exist only in the 683 // old methods). The class file parser places methods in order 684 // by method name, but does not order overloaded methods by 685 // signature. In order to determine what fate befell the methods, 686 // this code places the overloaded new methods that have matching 687 // old methods in the same order as the old methods and places 688 // new overloaded methods at the end of overloaded methods of 689 // that name. The code for this order normalization is adapted 690 // from the algorithm used in InstanceKlass::find_method(). 691 // Since we are swapping out of order entries as we find them, 692 // we only have to search forward through the overloaded methods. 693 // Methods which are added and have the same name as an existing 694 // method (but different signature) will be put at the end of 695 // the methods with that name, and the name mismatch code will 696 // handle them. 697 Array<Method*>* k_old_methods(the_class->methods()); 698 Array<Method*>* k_new_methods(scratch_class->methods()); 699 int n_old_methods = k_old_methods->length(); 700 int n_new_methods = k_new_methods->length(); 701 Thread* thread = Thread::current(); 702 703 int ni = 0; 704 int oi = 0; 705 while (true) { 706 Method* k_old_method; 707 Method* k_new_method; 708 enum { matched, added, deleted, undetermined } method_was = undetermined; 709 710 if (oi >= n_old_methods) { 711 if (ni >= n_new_methods) { 712 break; // we've looked at everything, done 713 } 714 // New method at the end 715 k_new_method = k_new_methods->at(ni); 716 method_was = added; 717 } else if (ni >= n_new_methods) { 718 // Old method, at the end, is deleted 719 k_old_method = k_old_methods->at(oi); 720 method_was = deleted; 721 } else { 722 // There are more methods in both the old and new lists 723 k_old_method = k_old_methods->at(oi); 724 k_new_method = k_new_methods->at(ni); 725 if (k_old_method->name() != k_new_method->name()) { 726 // Methods are sorted by method name, so a mismatch means added 727 // or deleted 728 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) { 729 method_was = added; 730 } else { 731 method_was = deleted; 732 } 733 } else if (k_old_method->signature() == k_new_method->signature()) { 734 // Both the name and signature match 735 method_was = matched; 736 } else { 737 // The name matches, but the signature doesn't, which means we have to 738 // search forward through the new overloaded methods. 739 int nj; // outside the loop for post-loop check 740 for (nj = ni + 1; nj < n_new_methods; nj++) { 741 Method* m = k_new_methods->at(nj); 742 if (k_old_method->name() != m->name()) { 743 // reached another method name so no more overloaded methods 744 method_was = deleted; 745 break; 746 } 747 if (k_old_method->signature() == m->signature()) { 748 // found a match so swap the methods 749 k_new_methods->at_put(ni, m); 750 k_new_methods->at_put(nj, k_new_method); 751 k_new_method = m; 752 method_was = matched; 753 break; 754 } 755 } 756 757 if (nj >= n_new_methods) { 758 // reached the end without a match; so method was deleted 759 method_was = deleted; 760 } 761 } 762 } 763 764 switch (method_was) { 765 case matched: 766 // methods match, be sure modifiers do too 767 old_flags = (jushort) k_old_method->access_flags().get_flags(); 768 new_flags = (jushort) k_new_method->access_flags().get_flags(); 769 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) { 770 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED; 771 } 772 { 773 u2 new_num = k_new_method->method_idnum(); 774 u2 old_num = k_old_method->method_idnum(); 775 if (new_num != old_num) { 776 Method* idnum_owner = scratch_class->method_with_idnum(old_num); 777 if (idnum_owner != NULL) { 778 // There is already a method assigned this idnum -- switch them 779 idnum_owner->set_method_idnum(new_num); 780 } 781 k_new_method->set_method_idnum(old_num); 782 if (thread->has_pending_exception()) { 783 return JVMTI_ERROR_OUT_OF_MEMORY; 784 } 785 } 786 } 787 RC_TRACE(0x00008000, ("Method matched: new: %s [%d] == old: %s [%d]", 788 k_new_method->name_and_sig_as_C_string(), ni, 789 k_old_method->name_and_sig_as_C_string(), oi)); 790 // advance to next pair of methods 791 ++oi; 792 ++ni; 793 break; 794 case added: 795 // method added, see if it is OK 796 new_flags = (jushort) k_new_method->access_flags().get_flags(); 797 if ((new_flags & JVM_ACC_PRIVATE) == 0 798 // hack: private should be treated as final, but alas 799 || (new_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0 800 ) { 801 // new methods must be private 802 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED; 803 } 804 { 805 u2 num = the_class->next_method_idnum(); 806 if (num == ConstMethod::UNSET_IDNUM) { 807 // cannot add any more methods 808 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED; 809 } 810 u2 new_num = k_new_method->method_idnum(); 811 Method* idnum_owner = scratch_class->method_with_idnum(num); 812 if (idnum_owner != NULL) { 813 // There is already a method assigned this idnum -- switch them 814 idnum_owner->set_method_idnum(new_num); 815 } 816 k_new_method->set_method_idnum(num); 817 if (thread->has_pending_exception()) { 818 return JVMTI_ERROR_OUT_OF_MEMORY; 819 } 820 } 821 RC_TRACE(0x00008000, ("Method added: new: %s [%d]", 822 k_new_method->name_and_sig_as_C_string(), ni)); 823 ++ni; // advance to next new method 824 break; 825 case deleted: 826 // method deleted, see if it is OK 827 old_flags = (jushort) k_old_method->access_flags().get_flags(); 828 if ((old_flags & JVM_ACC_PRIVATE) == 0 829 // hack: private should be treated as final, but alas 830 || (old_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0 831 ) { 832 // deleted methods must be private 833 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED; 834 } 835 RC_TRACE(0x00008000, ("Method deleted: old: %s [%d]", 836 k_old_method->name_and_sig_as_C_string(), oi)); 837 ++oi; // advance to next old method 838 break; 839 default: 840 ShouldNotReachHere(); 841 } 842 } 843 844 return JVMTI_ERROR_NONE; 845 } 846 847 848 // Find new constant pool index value for old constant pool index value 849 // by seaching the index map. Returns zero (0) if there is no mapped 850 // value for the old constant pool index. 851 int VM_RedefineClasses::find_new_index(int old_index) { 852 if (_index_map_count == 0) { 853 // map is empty so nothing can be found 854 return 0; 855 } 856 857 if (old_index < 1 || old_index >= _index_map_p->length()) { 858 // The old_index is out of range so it is not mapped. This should 859 // not happen in regular constant pool merging use, but it can 860 // happen if a corrupt annotation is processed. 861 return 0; 862 } 863 864 int value = _index_map_p->at(old_index); 865 if (value == -1) { 866 // the old_index is not mapped 867 return 0; 868 } 869 870 return value; 871 } // end find_new_index() 872 873 874 // Find new bootstrap specifier index value for old bootstrap specifier index 875 // value by seaching the index map. Returns unused index (-1) if there is 876 // no mapped value for the old bootstrap specifier index. 877 int VM_RedefineClasses::find_new_operand_index(int old_index) { 878 if (_operands_index_map_count == 0) { 879 // map is empty so nothing can be found 880 return -1; 881 } 882 883 if (old_index == -1 || old_index >= _operands_index_map_p->length()) { 884 // The old_index is out of range so it is not mapped. 885 // This should not happen in regular constant pool merging use. 886 return -1; 887 } 888 889 int value = _operands_index_map_p->at(old_index); 890 if (value == -1) { 891 // the old_index is not mapped 892 return -1; 893 } 894 895 return value; 896 } // end find_new_operand_index() 897 898 899 // Returns true if the current mismatch is due to a resolved/unresolved 900 // class pair. Otherwise, returns false. 901 bool VM_RedefineClasses::is_unresolved_class_mismatch(constantPoolHandle cp1, 902 int index1, constantPoolHandle cp2, int index2) { 903 904 jbyte t1 = cp1->tag_at(index1).value(); 905 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) { 906 return false; // wrong entry type; not our special case 907 } 908 909 jbyte t2 = cp2->tag_at(index2).value(); 910 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) { 911 return false; // wrong entry type; not our special case 912 } 913 914 if (t1 == t2) { 915 return false; // not a mismatch; not our special case 916 } 917 918 char *s1 = cp1->klass_name_at(index1)->as_C_string(); 919 char *s2 = cp2->klass_name_at(index2)->as_C_string(); 920 if (strcmp(s1, s2) != 0) { 921 return false; // strings don't match; not our special case 922 } 923 924 return true; // made it through the gauntlet; this is our special case 925 } // end is_unresolved_class_mismatch() 926 927 928 jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) { 929 930 // For consistency allocate memory using os::malloc wrapper. 931 _scratch_classes = (Klass**) 932 os::malloc(sizeof(Klass*) * _class_count, mtClass); 933 if (_scratch_classes == NULL) { 934 return JVMTI_ERROR_OUT_OF_MEMORY; 935 } 936 // Zero initialize the _scratch_classes array. 937 for (int i = 0; i < _class_count; i++) { 938 _scratch_classes[i] = NULL; 939 } 940 941 ResourceMark rm(THREAD); 942 943 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current()); 944 // state can only be NULL if the current thread is exiting which 945 // should not happen since we're trying to do a RedefineClasses 946 guarantee(state != NULL, "exiting thread calling load_new_class_versions"); 947 for (int i = 0; i < _class_count; i++) { 948 // Create HandleMark so that any handles created while loading new class 949 // versions are deleted. Constant pools are deallocated while merging 950 // constant pools 951 HandleMark hm(THREAD); 952 953 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass); 954 // classes for primitives cannot be redefined 955 if (!is_modifiable_class(mirror)) { 956 return JVMTI_ERROR_UNMODIFIABLE_CLASS; 957 } 958 Klass* the_class_oop = java_lang_Class::as_Klass(mirror); 959 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop); 960 Symbol* the_class_sym = the_class->name(); 961 962 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 963 RC_TRACE_WITH_THREAD(0x00000001, THREAD, 964 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)", 965 the_class->external_name(), _class_load_kind, 966 os::available_memory() >> 10)); 967 968 ClassFileStream st((u1*) _class_defs[i].class_bytes, 969 _class_defs[i].class_byte_count, (char *)"__VM_RedefineClasses__"); 970 971 // Parse the stream. 972 Handle the_class_loader(THREAD, the_class->class_loader()); 973 Handle protection_domain(THREAD, the_class->protection_domain()); 974 // Set redefined class handle in JvmtiThreadState class. 975 // This redefined class is sent to agent event handler for class file 976 // load hook event. 977 state->set_class_being_redefined(&the_class, _class_load_kind); 978 979 Klass* k = SystemDictionary::parse_stream(the_class_sym, 980 the_class_loader, 981 protection_domain, 982 &st, 983 THREAD); 984 // Clear class_being_redefined just to be sure. 985 state->clear_class_being_redefined(); 986 987 // TODO: if this is retransform, and nothing changed we can skip it 988 989 instanceKlassHandle scratch_class (THREAD, k); 990 991 // Need to clean up allocated InstanceKlass if there's an error so assign 992 // the result here. Caller deallocates all the scratch classes in case of 993 // an error. 994 _scratch_classes[i] = k; 995 996 if (HAS_PENDING_EXCEPTION) { 997 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 998 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 999 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("parse_stream exception: '%s'", 1000 ex_name->as_C_string())); 1001 CLEAR_PENDING_EXCEPTION; 1002 1003 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) { 1004 return JVMTI_ERROR_UNSUPPORTED_VERSION; 1005 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) { 1006 return JVMTI_ERROR_INVALID_CLASS_FORMAT; 1007 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) { 1008 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION; 1009 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) { 1010 // The message will be "XXX (wrong name: YYY)" 1011 return JVMTI_ERROR_NAMES_DONT_MATCH; 1012 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1013 return JVMTI_ERROR_OUT_OF_MEMORY; 1014 } else { // Just in case more exceptions can be thrown.. 1015 return JVMTI_ERROR_FAILS_VERIFICATION; 1016 } 1017 } 1018 1019 // Ensure class is linked before redefine 1020 if (!the_class->is_linked()) { 1021 the_class->link_class(THREAD); 1022 if (HAS_PENDING_EXCEPTION) { 1023 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1024 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1025 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("link_class exception: '%s'", 1026 ex_name->as_C_string())); 1027 CLEAR_PENDING_EXCEPTION; 1028 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1029 return JVMTI_ERROR_OUT_OF_MEMORY; 1030 } else { 1031 return JVMTI_ERROR_INTERNAL; 1032 } 1033 } 1034 } 1035 1036 // Do the validity checks in compare_and_normalize_class_versions() 1037 // before verifying the byte codes. By doing these checks first, we 1038 // limit the number of functions that require redirection from 1039 // the_class to scratch_class. In particular, we don't have to 1040 // modify JNI GetSuperclass() and thus won't change its performance. 1041 jvmtiError res = compare_and_normalize_class_versions(the_class, 1042 scratch_class); 1043 if (res != JVMTI_ERROR_NONE) { 1044 return res; 1045 } 1046 1047 // verify what the caller passed us 1048 { 1049 // The bug 6214132 caused the verification to fail. 1050 // Information about the_class and scratch_class is temporarily 1051 // recorded into jvmtiThreadState. This data is used to redirect 1052 // the_class to scratch_class in the JVM_* functions called by the 1053 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed 1054 // description. 1055 RedefineVerifyMark rvm(&the_class, &scratch_class, state); 1056 Verifier::verify( 1057 scratch_class, Verifier::ThrowException, true, THREAD); 1058 } 1059 1060 if (HAS_PENDING_EXCEPTION) { 1061 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1062 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1063 RC_TRACE_WITH_THREAD(0x00000002, THREAD, 1064 ("verify_byte_codes exception: '%s'", ex_name->as_C_string())); 1065 CLEAR_PENDING_EXCEPTION; 1066 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1067 return JVMTI_ERROR_OUT_OF_MEMORY; 1068 } else { 1069 // tell the caller the bytecodes are bad 1070 return JVMTI_ERROR_FAILS_VERIFICATION; 1071 } 1072 } 1073 1074 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD); 1075 if (HAS_PENDING_EXCEPTION) { 1076 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1077 CLEAR_PENDING_EXCEPTION; 1078 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1079 return JVMTI_ERROR_OUT_OF_MEMORY; 1080 } else { 1081 return JVMTI_ERROR_INTERNAL; 1082 } 1083 } 1084 1085 if (VerifyMergedCPBytecodes) { 1086 // verify what we have done during constant pool merging 1087 { 1088 RedefineVerifyMark rvm(&the_class, &scratch_class, state); 1089 Verifier::verify(scratch_class, Verifier::ThrowException, true, THREAD); 1090 } 1091 1092 if (HAS_PENDING_EXCEPTION) { 1093 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1094 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1095 RC_TRACE_WITH_THREAD(0x00000002, THREAD, 1096 ("verify_byte_codes post merge-CP exception: '%s'", 1097 ex_name->as_C_string())); 1098 CLEAR_PENDING_EXCEPTION; 1099 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1100 return JVMTI_ERROR_OUT_OF_MEMORY; 1101 } else { 1102 // tell the caller that constant pool merging screwed up 1103 return JVMTI_ERROR_INTERNAL; 1104 } 1105 } 1106 } 1107 1108 Rewriter::rewrite(scratch_class, THREAD); 1109 if (!HAS_PENDING_EXCEPTION) { 1110 scratch_class->link_methods(THREAD); 1111 } 1112 if (HAS_PENDING_EXCEPTION) { 1113 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1114 CLEAR_PENDING_EXCEPTION; 1115 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1116 return JVMTI_ERROR_OUT_OF_MEMORY; 1117 } else { 1118 return JVMTI_ERROR_INTERNAL; 1119 } 1120 } 1121 1122 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1123 RC_TRACE_WITH_THREAD(0x00000001, THREAD, 1124 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)", 1125 the_class->external_name(), os::available_memory() >> 10)); 1126 } 1127 1128 return JVMTI_ERROR_NONE; 1129 } 1130 1131 1132 // Map old_index to new_index as needed. scratch_cp is only needed 1133 // for RC_TRACE() calls. 1134 void VM_RedefineClasses::map_index(constantPoolHandle scratch_cp, 1135 int old_index, int new_index) { 1136 if (find_new_index(old_index) != 0) { 1137 // old_index is already mapped 1138 return; 1139 } 1140 1141 if (old_index == new_index) { 1142 // no mapping is needed 1143 return; 1144 } 1145 1146 _index_map_p->at_put(old_index, new_index); 1147 _index_map_count++; 1148 1149 RC_TRACE(0x00040000, ("mapped tag %d at index %d to %d", 1150 scratch_cp->tag_at(old_index).value(), old_index, new_index)); 1151 } // end map_index() 1152 1153 1154 // Map old_index to new_index as needed. 1155 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) { 1156 if (find_new_operand_index(old_index) != -1) { 1157 // old_index is already mapped 1158 return; 1159 } 1160 1161 if (old_index == new_index) { 1162 // no mapping is needed 1163 return; 1164 } 1165 1166 _operands_index_map_p->at_put(old_index, new_index); 1167 _operands_index_map_count++; 1168 1169 RC_TRACE(0x00040000, ("mapped bootstrap specifier at index %d to %d", old_index, new_index)); 1170 } // end map_index() 1171 1172 1173 // Merge old_cp and scratch_cp and return the results of the merge via 1174 // merge_cp_p. The number of entries in *merge_cp_p is returned via 1175 // merge_cp_length_p. The entries in old_cp occupy the same locations 1176 // in *merge_cp_p. Also creates a map of indices from entries in 1177 // scratch_cp to the corresponding entry in *merge_cp_p. Index map 1178 // entries are only created for entries in scratch_cp that occupy a 1179 // different location in *merged_cp_p. 1180 bool VM_RedefineClasses::merge_constant_pools(constantPoolHandle old_cp, 1181 constantPoolHandle scratch_cp, constantPoolHandle *merge_cp_p, 1182 int *merge_cp_length_p, TRAPS) { 1183 1184 if (merge_cp_p == NULL) { 1185 assert(false, "caller must provide scratch constantPool"); 1186 return false; // robustness 1187 } 1188 if (merge_cp_length_p == NULL) { 1189 assert(false, "caller must provide scratch CP length"); 1190 return false; // robustness 1191 } 1192 // Worst case we need old_cp->length() + scratch_cp()->length(), 1193 // but the caller might be smart so make sure we have at least 1194 // the minimum. 1195 if ((*merge_cp_p)->length() < old_cp->length()) { 1196 assert(false, "merge area too small"); 1197 return false; // robustness 1198 } 1199 1200 RC_TRACE_WITH_THREAD(0x00010000, THREAD, 1201 ("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(), 1202 scratch_cp->length())); 1203 1204 { 1205 // Pass 0: 1206 // The old_cp is copied to *merge_cp_p; this means that any code 1207 // using old_cp does not have to change. This work looks like a 1208 // perfect fit for ConstantPool*::copy_cp_to(), but we need to 1209 // handle one special case: 1210 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass 1211 // This will make verification happy. 1212 1213 int old_i; // index into old_cp 1214 1215 // index zero (0) is not used in constantPools 1216 for (old_i = 1; old_i < old_cp->length(); old_i++) { 1217 // leave debugging crumb 1218 jbyte old_tag = old_cp->tag_at(old_i).value(); 1219 switch (old_tag) { 1220 case JVM_CONSTANT_Class: 1221 case JVM_CONSTANT_UnresolvedClass: 1222 // revert the copy to JVM_CONSTANT_UnresolvedClass 1223 // May be resolving while calling this so do the same for 1224 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition) 1225 (*merge_cp_p)->unresolved_klass_at_put(old_i, 1226 old_cp->klass_name_at(old_i)); 1227 break; 1228 1229 case JVM_CONSTANT_Double: 1230 case JVM_CONSTANT_Long: 1231 // just copy the entry to *merge_cp_p, but double and long take 1232 // two constant pool entries 1233 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0); 1234 old_i++; 1235 break; 1236 1237 default: 1238 // just copy the entry to *merge_cp_p 1239 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0); 1240 break; 1241 } 1242 } // end for each old_cp entry 1243 1244 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_0); 1245 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_0); 1246 1247 // We don't need to sanity check that *merge_cp_length_p is within 1248 // *merge_cp_p bounds since we have the minimum on-entry check above. 1249 (*merge_cp_length_p) = old_i; 1250 } 1251 1252 // merge_cp_len should be the same as old_cp->length() at this point 1253 // so this trace message is really a "warm-and-breathing" message. 1254 RC_TRACE_WITH_THREAD(0x00020000, THREAD, 1255 ("after pass 0: merge_cp_len=%d", *merge_cp_length_p)); 1256 1257 int scratch_i; // index into scratch_cp 1258 { 1259 // Pass 1a: 1260 // Compare scratch_cp entries to the old_cp entries that we have 1261 // already copied to *merge_cp_p. In this pass, we are eliminating 1262 // exact duplicates (matching entry at same index) so we only 1263 // compare entries in the common indice range. 1264 int increment = 1; 1265 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length()); 1266 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) { 1267 switch (scratch_cp->tag_at(scratch_i).value()) { 1268 case JVM_CONSTANT_Double: 1269 case JVM_CONSTANT_Long: 1270 // double and long take two constant pool entries 1271 increment = 2; 1272 break; 1273 1274 default: 1275 increment = 1; 1276 break; 1277 } 1278 1279 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p, 1280 scratch_i, CHECK_0); 1281 if (match) { 1282 // found a match at the same index so nothing more to do 1283 continue; 1284 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i, 1285 *merge_cp_p, scratch_i)) { 1286 // The mismatch in compare_entry_to() above is because of a 1287 // resolved versus unresolved class entry at the same index 1288 // with the same string value. Since Pass 0 reverted any 1289 // class entries to unresolved class entries in *merge_cp_p, 1290 // we go with the unresolved class entry. 1291 continue; 1292 } 1293 1294 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, 1295 CHECK_0); 1296 if (found_i != 0) { 1297 guarantee(found_i != scratch_i, 1298 "compare_entry_to() and find_matching_entry() do not agree"); 1299 1300 // Found a matching entry somewhere else in *merge_cp_p so 1301 // just need a mapping entry. 1302 map_index(scratch_cp, scratch_i, found_i); 1303 continue; 1304 } 1305 1306 // The find_matching_entry() call above could fail to find a match 1307 // due to a resolved versus unresolved class or string entry situation 1308 // like we solved above with the is_unresolved_*_mismatch() calls. 1309 // However, we would have to call is_unresolved_*_mismatch() over 1310 // all of *merge_cp_p (potentially) and that doesn't seem to be 1311 // worth the time. 1312 1313 // No match found so we have to append this entry and any unique 1314 // referenced entries to *merge_cp_p. 1315 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p, 1316 CHECK_0); 1317 } 1318 } 1319 1320 RC_TRACE_WITH_THREAD(0x00020000, THREAD, 1321 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", 1322 *merge_cp_length_p, scratch_i, _index_map_count)); 1323 1324 if (scratch_i < scratch_cp->length()) { 1325 // Pass 1b: 1326 // old_cp is smaller than scratch_cp so there are entries in 1327 // scratch_cp that we have not yet processed. We take care of 1328 // those now. 1329 int increment = 1; 1330 for (; scratch_i < scratch_cp->length(); scratch_i += increment) { 1331 switch (scratch_cp->tag_at(scratch_i).value()) { 1332 case JVM_CONSTANT_Double: 1333 case JVM_CONSTANT_Long: 1334 // double and long take two constant pool entries 1335 increment = 2; 1336 break; 1337 1338 default: 1339 increment = 1; 1340 break; 1341 } 1342 1343 int found_i = 1344 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0); 1345 if (found_i != 0) { 1346 // Found a matching entry somewhere else in *merge_cp_p so 1347 // just need a mapping entry. 1348 map_index(scratch_cp, scratch_i, found_i); 1349 continue; 1350 } 1351 1352 // No match found so we have to append this entry and any unique 1353 // referenced entries to *merge_cp_p. 1354 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p, 1355 CHECK_0); 1356 } 1357 1358 RC_TRACE_WITH_THREAD(0x00020000, THREAD, 1359 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", 1360 *merge_cp_length_p, scratch_i, _index_map_count)); 1361 } 1362 finalize_operands_merge(*merge_cp_p, THREAD); 1363 1364 return true; 1365 } // end merge_constant_pools() 1366 1367 1368 // Scoped object to clean up the constant pool(s) created for merging 1369 class MergeCPCleaner { 1370 ClassLoaderData* _loader_data; 1371 ConstantPool* _cp; 1372 ConstantPool* _scratch_cp; 1373 public: 1374 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) : 1375 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {} 1376 ~MergeCPCleaner() { 1377 _loader_data->add_to_deallocate_list(_cp); 1378 if (_scratch_cp != NULL) { 1379 _loader_data->add_to_deallocate_list(_scratch_cp); 1380 } 1381 } 1382 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; } 1383 }; 1384 1385 // Merge constant pools between the_class and scratch_class and 1386 // potentially rewrite bytecodes in scratch_class to use the merged 1387 // constant pool. 1388 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite( 1389 instanceKlassHandle the_class, instanceKlassHandle scratch_class, 1390 TRAPS) { 1391 // worst case merged constant pool length is old and new combined 1392 int merge_cp_length = the_class->constants()->length() 1393 + scratch_class->constants()->length(); 1394 1395 // Constant pools are not easily reused so we allocate a new one 1396 // each time. 1397 // merge_cp is created unsafe for concurrent GC processing. It 1398 // should be marked safe before discarding it. Even though 1399 // garbage, if it crosses a card boundary, it may be scanned 1400 // in order to find the start of the first complete object on the card. 1401 ClassLoaderData* loader_data = the_class->class_loader_data(); 1402 ConstantPool* merge_cp_oop = 1403 ConstantPool::allocate(loader_data, 1404 merge_cp_length, 1405 THREAD); 1406 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop); 1407 1408 HandleMark hm(THREAD); // make sure handles are cleared before 1409 // MergeCPCleaner clears out merge_cp_oop 1410 constantPoolHandle merge_cp(THREAD, merge_cp_oop); 1411 1412 // Get constants() from the old class because it could have been rewritten 1413 // while we were at a safepoint allocating a new constant pool. 1414 constantPoolHandle old_cp(THREAD, the_class->constants()); 1415 constantPoolHandle scratch_cp(THREAD, scratch_class->constants()); 1416 1417 // If the length changed, the class was redefined out from under us. Return 1418 // an error. 1419 if (merge_cp_length != the_class->constants()->length() 1420 + scratch_class->constants()->length()) { 1421 return JVMTI_ERROR_INTERNAL; 1422 } 1423 1424 // Update the version number of the constant pool 1425 merge_cp->increment_and_save_version(old_cp->version()); 1426 1427 ResourceMark rm(THREAD); 1428 _index_map_count = 0; 1429 _index_map_p = new intArray(scratch_cp->length(), -1); 1430 1431 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands()); 1432 _operands_index_map_count = 0; 1433 _operands_index_map_p = new intArray( 1434 ConstantPool::operand_array_length(scratch_cp->operands()), -1); 1435 1436 // reference to the cp holder is needed for copy_operands() 1437 merge_cp->set_pool_holder(scratch_class()); 1438 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp, 1439 &merge_cp_length, THREAD); 1440 merge_cp->set_pool_holder(NULL); 1441 1442 if (!result) { 1443 // The merge can fail due to memory allocation failure or due 1444 // to robustness checks. 1445 return JVMTI_ERROR_INTERNAL; 1446 } 1447 1448 RC_TRACE_WITH_THREAD(0x00010000, THREAD, 1449 ("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count)); 1450 1451 if (_index_map_count == 0) { 1452 // there is nothing to map between the new and merged constant pools 1453 1454 if (old_cp->length() == scratch_cp->length()) { 1455 // The old and new constant pools are the same length and the 1456 // index map is empty. This means that the three constant pools 1457 // are equivalent (but not the same). Unfortunately, the new 1458 // constant pool has not gone through link resolution nor have 1459 // the new class bytecodes gone through constant pool cache 1460 // rewriting so we can't use the old constant pool with the new 1461 // class. 1462 1463 // toss the merged constant pool at return 1464 } else if (old_cp->length() < scratch_cp->length()) { 1465 // The old constant pool has fewer entries than the new constant 1466 // pool and the index map is empty. This means the new constant 1467 // pool is a superset of the old constant pool. However, the old 1468 // class bytecodes have already gone through constant pool cache 1469 // rewriting so we can't use the new constant pool with the old 1470 // class. 1471 1472 // toss the merged constant pool at return 1473 } else { 1474 // The old constant pool has more entries than the new constant 1475 // pool and the index map is empty. This means that both the old 1476 // and merged constant pools are supersets of the new constant 1477 // pool. 1478 1479 // Replace the new constant pool with a shrunken copy of the 1480 // merged constant pool 1481 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, THREAD); 1482 // The new constant pool replaces scratch_cp so have cleaner clean it up. 1483 // It can't be cleaned up while there are handles to it. 1484 cp_cleaner.add_scratch_cp(scratch_cp()); 1485 } 1486 } else { 1487 if (RC_TRACE_ENABLED(0x00040000)) { 1488 // don't want to loop unless we are tracing 1489 int count = 0; 1490 for (int i = 1; i < _index_map_p->length(); i++) { 1491 int value = _index_map_p->at(i); 1492 1493 if (value != -1) { 1494 RC_TRACE_WITH_THREAD(0x00040000, THREAD, 1495 ("index_map[%d]: old=%d new=%d", count, i, value)); 1496 count++; 1497 } 1498 } 1499 } 1500 1501 // We have entries mapped between the new and merged constant pools 1502 // so we have to rewrite some constant pool references. 1503 if (!rewrite_cp_refs(scratch_class, THREAD)) { 1504 return JVMTI_ERROR_INTERNAL; 1505 } 1506 1507 // Replace the new constant pool with a shrunken copy of the 1508 // merged constant pool so now the rewritten bytecodes have 1509 // valid references; the previous new constant pool will get 1510 // GCed. 1511 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, THREAD); 1512 // The new constant pool replaces scratch_cp so have cleaner clean it up. 1513 // It can't be cleaned up while there are handles to it. 1514 cp_cleaner.add_scratch_cp(scratch_cp()); 1515 } 1516 1517 return JVMTI_ERROR_NONE; 1518 } // end merge_cp_and_rewrite() 1519 1520 1521 // Rewrite constant pool references in klass scratch_class. 1522 bool VM_RedefineClasses::rewrite_cp_refs(instanceKlassHandle scratch_class, 1523 TRAPS) { 1524 1525 // rewrite constant pool references in the methods: 1526 if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) { 1527 // propagate failure back to caller 1528 return false; 1529 } 1530 1531 // rewrite constant pool references in the class_annotations: 1532 if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) { 1533 // propagate failure back to caller 1534 return false; 1535 } 1536 1537 // rewrite constant pool references in the fields_annotations: 1538 if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) { 1539 // propagate failure back to caller 1540 return false; 1541 } 1542 1543 // rewrite constant pool references in the methods_annotations: 1544 if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) { 1545 // propagate failure back to caller 1546 return false; 1547 } 1548 1549 // rewrite constant pool references in the methods_parameter_annotations: 1550 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class, 1551 THREAD)) { 1552 // propagate failure back to caller 1553 return false; 1554 } 1555 1556 // rewrite constant pool references in the methods_default_annotations: 1557 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class, 1558 THREAD)) { 1559 // propagate failure back to caller 1560 return false; 1561 } 1562 1563 // rewrite source file name index: 1564 u2 source_file_name_idx = scratch_class->source_file_name_index(); 1565 if (source_file_name_idx != 0) { 1566 u2 new_source_file_name_idx = find_new_index(source_file_name_idx); 1567 if (new_source_file_name_idx != 0) { 1568 scratch_class->set_source_file_name_index(new_source_file_name_idx); 1569 } 1570 } 1571 1572 // rewrite class generic signature index: 1573 u2 generic_signature_index = scratch_class->generic_signature_index(); 1574 if (generic_signature_index != 0) { 1575 u2 new_generic_signature_index = find_new_index(generic_signature_index); 1576 if (new_generic_signature_index != 0) { 1577 scratch_class->set_generic_signature_index(new_generic_signature_index); 1578 } 1579 } 1580 1581 return true; 1582 } // end rewrite_cp_refs() 1583 1584 // Rewrite constant pool references in the methods. 1585 bool VM_RedefineClasses::rewrite_cp_refs_in_methods( 1586 instanceKlassHandle scratch_class, TRAPS) { 1587 1588 Array<Method*>* methods = scratch_class->methods(); 1589 1590 if (methods == NULL || methods->length() == 0) { 1591 // no methods so nothing to do 1592 return true; 1593 } 1594 1595 // rewrite constant pool references in the methods: 1596 for (int i = methods->length() - 1; i >= 0; i--) { 1597 methodHandle method(THREAD, methods->at(i)); 1598 methodHandle new_method; 1599 rewrite_cp_refs_in_method(method, &new_method, CHECK_false); 1600 if (!new_method.is_null()) { 1601 // the method has been replaced so save the new method version 1602 methods->at_put(i, new_method()); 1603 } 1604 } 1605 1606 return true; 1607 } 1608 1609 1610 // Rewrite constant pool references in the specific method. This code 1611 // was adapted from Rewriter::rewrite_method(). 1612 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method, 1613 methodHandle *new_method_p, TRAPS) { 1614 1615 *new_method_p = methodHandle(); // default is no new method 1616 1617 // We cache a pointer to the bytecodes here in code_base. If GC 1618 // moves the Method*, then the bytecodes will also move which 1619 // will likely cause a crash. We create a No_Safepoint_Verifier 1620 // object to detect whether we pass a possible safepoint in this 1621 // code block. 1622 No_Safepoint_Verifier nsv; 1623 1624 // Bytecodes and their length 1625 address code_base = method->code_base(); 1626 int code_length = method->code_size(); 1627 1628 int bc_length; 1629 for (int bci = 0; bci < code_length; bci += bc_length) { 1630 address bcp = code_base + bci; 1631 Bytecodes::Code c = (Bytecodes::Code)(*bcp); 1632 1633 bc_length = Bytecodes::length_for(c); 1634 if (bc_length == 0) { 1635 // More complicated bytecodes report a length of zero so 1636 // we have to try again a slightly different way. 1637 bc_length = Bytecodes::length_at(method(), bcp); 1638 } 1639 1640 assert(bc_length != 0, "impossible bytecode length"); 1641 1642 switch (c) { 1643 case Bytecodes::_ldc: 1644 { 1645 int cp_index = *(bcp + 1); 1646 int new_index = find_new_index(cp_index); 1647 1648 if (StressLdcRewrite && new_index == 0) { 1649 // If we are stressing ldc -> ldc_w rewriting, then we 1650 // always need a new_index value. 1651 new_index = cp_index; 1652 } 1653 if (new_index != 0) { 1654 // the original index is mapped so we have more work to do 1655 if (!StressLdcRewrite && new_index <= max_jubyte) { 1656 // The new value can still use ldc instead of ldc_w 1657 // unless we are trying to stress ldc -> ldc_w rewriting 1658 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 1659 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), 1660 bcp, cp_index, new_index)); 1661 *(bcp + 1) = new_index; 1662 } else { 1663 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 1664 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d", 1665 Bytecodes::name(c), bcp, cp_index, new_index)); 1666 // the new value needs ldc_w instead of ldc 1667 u_char inst_buffer[4]; // max instruction size is 4 bytes 1668 bcp = (address)inst_buffer; 1669 // construct new instruction sequence 1670 *bcp = Bytecodes::_ldc_w; 1671 bcp++; 1672 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w. 1673 // See comment below for difference between put_Java_u2() 1674 // and put_native_u2(). 1675 Bytes::put_Java_u2(bcp, new_index); 1676 1677 Relocator rc(method, NULL /* no RelocatorListener needed */); 1678 methodHandle m; 1679 { 1680 Pause_No_Safepoint_Verifier pnsv(&nsv); 1681 1682 // ldc is 2 bytes and ldc_w is 3 bytes 1683 m = rc.insert_space_at(bci, 3, inst_buffer, THREAD); 1684 if (m.is_null() || HAS_PENDING_EXCEPTION) { 1685 guarantee(false, "insert_space_at() failed"); 1686 } 1687 } 1688 1689 // return the new method so that the caller can update 1690 // the containing class 1691 *new_method_p = method = m; 1692 // switch our bytecode processing loop from the old method 1693 // to the new method 1694 code_base = method->code_base(); 1695 code_length = method->code_size(); 1696 bcp = code_base + bci; 1697 c = (Bytecodes::Code)(*bcp); 1698 bc_length = Bytecodes::length_for(c); 1699 assert(bc_length != 0, "sanity check"); 1700 } // end we need ldc_w instead of ldc 1701 } // end if there is a mapped index 1702 } break; 1703 1704 // these bytecodes have a two-byte constant pool index 1705 case Bytecodes::_anewarray : // fall through 1706 case Bytecodes::_checkcast : // fall through 1707 case Bytecodes::_getfield : // fall through 1708 case Bytecodes::_getstatic : // fall through 1709 case Bytecodes::_instanceof : // fall through 1710 case Bytecodes::_invokedynamic : // fall through 1711 case Bytecodes::_invokeinterface: // fall through 1712 case Bytecodes::_invokespecial : // fall through 1713 case Bytecodes::_invokestatic : // fall through 1714 case Bytecodes::_invokevirtual : // fall through 1715 case Bytecodes::_ldc_w : // fall through 1716 case Bytecodes::_ldc2_w : // fall through 1717 case Bytecodes::_multianewarray : // fall through 1718 case Bytecodes::_new : // fall through 1719 case Bytecodes::_putfield : // fall through 1720 case Bytecodes::_putstatic : 1721 { 1722 address p = bcp + 1; 1723 int cp_index = Bytes::get_Java_u2(p); 1724 int new_index = find_new_index(cp_index); 1725 if (new_index != 0) { 1726 // the original index is mapped so update w/ new value 1727 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 1728 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), 1729 bcp, cp_index, new_index)); 1730 // Rewriter::rewrite_method() uses put_native_u2() in this 1731 // situation because it is reusing the constant pool index 1732 // location for a native index into the ConstantPoolCache. 1733 // Since we are updating the constant pool index prior to 1734 // verification and ConstantPoolCache initialization, we 1735 // need to keep the new index in Java byte order. 1736 Bytes::put_Java_u2(p, new_index); 1737 } 1738 } break; 1739 } 1740 } // end for each bytecode 1741 1742 // We also need to rewrite the parameter name indexes, if there is 1743 // method parameter data present 1744 if(method->has_method_parameters()) { 1745 const int len = method->method_parameters_length(); 1746 MethodParametersElement* elem = method->method_parameters_start(); 1747 1748 for (int i = 0; i < len; i++) { 1749 const u2 cp_index = elem[i].name_cp_index; 1750 const u2 new_cp_index = find_new_index(cp_index); 1751 if (new_cp_index != 0) { 1752 elem[i].name_cp_index = new_cp_index; 1753 } 1754 } 1755 } 1756 } // end rewrite_cp_refs_in_method() 1757 1758 1759 // Rewrite constant pool references in the class_annotations field. 1760 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations( 1761 instanceKlassHandle scratch_class, TRAPS) { 1762 1763 AnnotationArray* class_annotations = scratch_class->class_annotations(); 1764 if (class_annotations == NULL || class_annotations->length() == 0) { 1765 // no class_annotations so nothing to do 1766 return true; 1767 } 1768 1769 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1770 ("class_annotations length=%d", class_annotations->length())); 1771 1772 int byte_i = 0; // byte index into class_annotations 1773 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i, 1774 THREAD); 1775 } 1776 1777 1778 // Rewrite constant pool references in an annotations typeArray. This 1779 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute 1780 // that is described in section 4.8.15 of the 2nd-edition of the VM spec: 1781 // 1782 // annotations_typeArray { 1783 // u2 num_annotations; 1784 // annotation annotations[num_annotations]; 1785 // } 1786 // 1787 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray( 1788 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) { 1789 1790 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 1791 // not enough room for num_annotations field 1792 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1793 ("length() is too small for num_annotations field")); 1794 return false; 1795 } 1796 1797 u2 num_annotations = Bytes::get_Java_u2((address) 1798 annotations_typeArray->adr_at(byte_i_ref)); 1799 byte_i_ref += 2; 1800 1801 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1802 ("num_annotations=%d", num_annotations)); 1803 1804 int calc_num_annotations = 0; 1805 for (; calc_num_annotations < num_annotations; calc_num_annotations++) { 1806 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, 1807 byte_i_ref, THREAD)) { 1808 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1809 ("bad annotation_struct at %d", calc_num_annotations)); 1810 // propagate failure back to caller 1811 return false; 1812 } 1813 } 1814 assert(num_annotations == calc_num_annotations, "sanity check"); 1815 1816 return true; 1817 } // end rewrite_cp_refs_in_annotations_typeArray() 1818 1819 1820 // Rewrite constant pool references in the annotation struct portion of 1821 // an annotations_typeArray. This "structure" is from section 4.8.15 of 1822 // the 2nd-edition of the VM spec: 1823 // 1824 // struct annotation { 1825 // u2 type_index; 1826 // u2 num_element_value_pairs; 1827 // { 1828 // u2 element_name_index; 1829 // element_value value; 1830 // } element_value_pairs[num_element_value_pairs]; 1831 // } 1832 // 1833 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct( 1834 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) { 1835 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) { 1836 // not enough room for smallest annotation_struct 1837 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1838 ("length() is too small for annotation_struct")); 1839 return false; 1840 } 1841 1842 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray, 1843 byte_i_ref, "mapped old type_index=%d", THREAD); 1844 1845 u2 num_element_value_pairs = Bytes::get_Java_u2((address) 1846 annotations_typeArray->adr_at(byte_i_ref)); 1847 byte_i_ref += 2; 1848 1849 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1850 ("type_index=%d num_element_value_pairs=%d", type_index, 1851 num_element_value_pairs)); 1852 1853 int calc_num_element_value_pairs = 0; 1854 for (; calc_num_element_value_pairs < num_element_value_pairs; 1855 calc_num_element_value_pairs++) { 1856 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 1857 // not enough room for another element_name_index, let alone 1858 // the rest of another component 1859 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1860 ("length() is too small for element_name_index")); 1861 return false; 1862 } 1863 1864 u2 element_name_index = rewrite_cp_ref_in_annotation_data( 1865 annotations_typeArray, byte_i_ref, 1866 "mapped old element_name_index=%d", THREAD); 1867 1868 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1869 ("element_name_index=%d", element_name_index)); 1870 1871 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, 1872 byte_i_ref, THREAD)) { 1873 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1874 ("bad element_value at %d", calc_num_element_value_pairs)); 1875 // propagate failure back to caller 1876 return false; 1877 } 1878 } // end for each component 1879 assert(num_element_value_pairs == calc_num_element_value_pairs, 1880 "sanity check"); 1881 1882 return true; 1883 } // end rewrite_cp_refs_in_annotation_struct() 1884 1885 1886 // Rewrite a constant pool reference at the current position in 1887 // annotations_typeArray if needed. Returns the original constant 1888 // pool reference if a rewrite was not needed or the new constant 1889 // pool reference if a rewrite was needed. 1890 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data( 1891 AnnotationArray* annotations_typeArray, int &byte_i_ref, 1892 const char * trace_mesg, TRAPS) { 1893 1894 address cp_index_addr = (address) 1895 annotations_typeArray->adr_at(byte_i_ref); 1896 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr); 1897 u2 new_cp_index = find_new_index(old_cp_index); 1898 if (new_cp_index != 0) { 1899 RC_TRACE_WITH_THREAD(0x02000000, THREAD, (trace_mesg, old_cp_index)); 1900 Bytes::put_Java_u2(cp_index_addr, new_cp_index); 1901 old_cp_index = new_cp_index; 1902 } 1903 byte_i_ref += 2; 1904 return old_cp_index; 1905 } 1906 1907 1908 // Rewrite constant pool references in the element_value portion of an 1909 // annotations_typeArray. This "structure" is from section 4.8.15.1 of 1910 // the 2nd-edition of the VM spec: 1911 // 1912 // struct element_value { 1913 // u1 tag; 1914 // union { 1915 // u2 const_value_index; 1916 // { 1917 // u2 type_name_index; 1918 // u2 const_name_index; 1919 // } enum_const_value; 1920 // u2 class_info_index; 1921 // annotation annotation_value; 1922 // struct { 1923 // u2 num_values; 1924 // element_value values[num_values]; 1925 // } array_value; 1926 // } value; 1927 // } 1928 // 1929 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value( 1930 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) { 1931 1932 if ((byte_i_ref + 1) > annotations_typeArray->length()) { 1933 // not enough room for a tag let alone the rest of an element_value 1934 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1935 ("length() is too small for a tag")); 1936 return false; 1937 } 1938 1939 u1 tag = annotations_typeArray->at(byte_i_ref); 1940 byte_i_ref++; 1941 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("tag='%c'", tag)); 1942 1943 switch (tag) { 1944 // These BaseType tag values are from Table 4.2 in VM spec: 1945 case 'B': // byte 1946 case 'C': // char 1947 case 'D': // double 1948 case 'F': // float 1949 case 'I': // int 1950 case 'J': // long 1951 case 'S': // short 1952 case 'Z': // boolean 1953 1954 // The remaining tag values are from Table 4.8 in the 2nd-edition of 1955 // the VM spec: 1956 case 's': 1957 { 1958 // For the above tag values (including the BaseType values), 1959 // value.const_value_index is right union field. 1960 1961 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 1962 // not enough room for a const_value_index 1963 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1964 ("length() is too small for a const_value_index")); 1965 return false; 1966 } 1967 1968 u2 const_value_index = rewrite_cp_ref_in_annotation_data( 1969 annotations_typeArray, byte_i_ref, 1970 "mapped old const_value_index=%d", THREAD); 1971 1972 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1973 ("const_value_index=%d", const_value_index)); 1974 } break; 1975 1976 case 'e': 1977 { 1978 // for the above tag value, value.enum_const_value is right union field 1979 1980 if ((byte_i_ref + 4) > annotations_typeArray->length()) { 1981 // not enough room for a enum_const_value 1982 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1983 ("length() is too small for a enum_const_value")); 1984 return false; 1985 } 1986 1987 u2 type_name_index = rewrite_cp_ref_in_annotation_data( 1988 annotations_typeArray, byte_i_ref, 1989 "mapped old type_name_index=%d", THREAD); 1990 1991 u2 const_name_index = rewrite_cp_ref_in_annotation_data( 1992 annotations_typeArray, byte_i_ref, 1993 "mapped old const_name_index=%d", THREAD); 1994 1995 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1996 ("type_name_index=%d const_name_index=%d", type_name_index, 1997 const_name_index)); 1998 } break; 1999 2000 case 'c': 2001 { 2002 // for the above tag value, value.class_info_index is right union field 2003 2004 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2005 // not enough room for a class_info_index 2006 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2007 ("length() is too small for a class_info_index")); 2008 return false; 2009 } 2010 2011 u2 class_info_index = rewrite_cp_ref_in_annotation_data( 2012 annotations_typeArray, byte_i_ref, 2013 "mapped old class_info_index=%d", THREAD); 2014 2015 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2016 ("class_info_index=%d", class_info_index)); 2017 } break; 2018 2019 case '@': 2020 // For the above tag value, value.attr_value is the right union 2021 // field. This is a nested annotation. 2022 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, 2023 byte_i_ref, THREAD)) { 2024 // propagate failure back to caller 2025 return false; 2026 } 2027 break; 2028 2029 case '[': 2030 { 2031 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2032 // not enough room for a num_values field 2033 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2034 ("length() is too small for a num_values field")); 2035 return false; 2036 } 2037 2038 // For the above tag value, value.array_value is the right union 2039 // field. This is an array of nested element_value. 2040 u2 num_values = Bytes::get_Java_u2((address) 2041 annotations_typeArray->adr_at(byte_i_ref)); 2042 byte_i_ref += 2; 2043 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("num_values=%d", num_values)); 2044 2045 int calc_num_values = 0; 2046 for (; calc_num_values < num_values; calc_num_values++) { 2047 if (!rewrite_cp_refs_in_element_value( 2048 annotations_typeArray, byte_i_ref, THREAD)) { 2049 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2050 ("bad nested element_value at %d", calc_num_values)); 2051 // propagate failure back to caller 2052 return false; 2053 } 2054 } 2055 assert(num_values == calc_num_values, "sanity check"); 2056 } break; 2057 2058 default: 2059 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("bad tag=0x%x", tag)); 2060 return false; 2061 } // end decode tag field 2062 2063 return true; 2064 } // end rewrite_cp_refs_in_element_value() 2065 2066 2067 // Rewrite constant pool references in a fields_annotations field. 2068 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations( 2069 instanceKlassHandle scratch_class, TRAPS) { 2070 2071 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations(); 2072 2073 if (fields_annotations == NULL || fields_annotations->length() == 0) { 2074 // no fields_annotations so nothing to do 2075 return true; 2076 } 2077 2078 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2079 ("fields_annotations length=%d", fields_annotations->length())); 2080 2081 for (int i = 0; i < fields_annotations->length(); i++) { 2082 AnnotationArray* field_annotations = fields_annotations->at(i); 2083 if (field_annotations == NULL || field_annotations->length() == 0) { 2084 // this field does not have any annotations so skip it 2085 continue; 2086 } 2087 2088 int byte_i = 0; // byte index into field_annotations 2089 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i, 2090 THREAD)) { 2091 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2092 ("bad field_annotations at %d", i)); 2093 // propagate failure back to caller 2094 return false; 2095 } 2096 } 2097 2098 return true; 2099 } // end rewrite_cp_refs_in_fields_annotations() 2100 2101 2102 // Rewrite constant pool references in a methods_annotations field. 2103 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations( 2104 instanceKlassHandle scratch_class, TRAPS) { 2105 2106 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2107 Method* m = scratch_class->methods()->at(i); 2108 AnnotationArray* method_annotations = m->constMethod()->method_annotations(); 2109 2110 if (method_annotations == NULL || method_annotations->length() == 0) { 2111 // this method does not have any annotations so skip it 2112 continue; 2113 } 2114 2115 int byte_i = 0; // byte index into method_annotations 2116 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i, 2117 THREAD)) { 2118 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2119 ("bad method_annotations at %d", i)); 2120 // propagate failure back to caller 2121 return false; 2122 } 2123 } 2124 2125 return true; 2126 } // end rewrite_cp_refs_in_methods_annotations() 2127 2128 2129 // Rewrite constant pool references in a methods_parameter_annotations 2130 // field. This "structure" is adapted from the 2131 // RuntimeVisibleParameterAnnotations_attribute described in section 2132 // 4.8.17 of the 2nd-edition of the VM spec: 2133 // 2134 // methods_parameter_annotations_typeArray { 2135 // u1 num_parameters; 2136 // { 2137 // u2 num_annotations; 2138 // annotation annotations[num_annotations]; 2139 // } parameter_annotations[num_parameters]; 2140 // } 2141 // 2142 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations( 2143 instanceKlassHandle scratch_class, TRAPS) { 2144 2145 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2146 Method* m = scratch_class->methods()->at(i); 2147 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations(); 2148 if (method_parameter_annotations == NULL 2149 || method_parameter_annotations->length() == 0) { 2150 // this method does not have any parameter annotations so skip it 2151 continue; 2152 } 2153 2154 if (method_parameter_annotations->length() < 1) { 2155 // not enough room for a num_parameters field 2156 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2157 ("length() is too small for a num_parameters field at %d", i)); 2158 return false; 2159 } 2160 2161 int byte_i = 0; // byte index into method_parameter_annotations 2162 2163 u1 num_parameters = method_parameter_annotations->at(byte_i); 2164 byte_i++; 2165 2166 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2167 ("num_parameters=%d", num_parameters)); 2168 2169 int calc_num_parameters = 0; 2170 for (; calc_num_parameters < num_parameters; calc_num_parameters++) { 2171 if (!rewrite_cp_refs_in_annotations_typeArray( 2172 method_parameter_annotations, byte_i, THREAD)) { 2173 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2174 ("bad method_parameter_annotations at %d", calc_num_parameters)); 2175 // propagate failure back to caller 2176 return false; 2177 } 2178 } 2179 assert(num_parameters == calc_num_parameters, "sanity check"); 2180 } 2181 2182 return true; 2183 } // end rewrite_cp_refs_in_methods_parameter_annotations() 2184 2185 2186 // Rewrite constant pool references in a methods_default_annotations 2187 // field. This "structure" is adapted from the AnnotationDefault_attribute 2188 // that is described in section 4.8.19 of the 2nd-edition of the VM spec: 2189 // 2190 // methods_default_annotations_typeArray { 2191 // element_value default_value; 2192 // } 2193 // 2194 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations( 2195 instanceKlassHandle scratch_class, TRAPS) { 2196 2197 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2198 Method* m = scratch_class->methods()->at(i); 2199 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations(); 2200 if (method_default_annotations == NULL 2201 || method_default_annotations->length() == 0) { 2202 // this method does not have any default annotations so skip it 2203 continue; 2204 } 2205 2206 int byte_i = 0; // byte index into method_default_annotations 2207 2208 if (!rewrite_cp_refs_in_element_value( 2209 method_default_annotations, byte_i, THREAD)) { 2210 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2211 ("bad default element_value at %d", i)); 2212 // propagate failure back to caller 2213 return false; 2214 } 2215 } 2216 2217 return true; 2218 } // end rewrite_cp_refs_in_methods_default_annotations() 2219 2220 2221 // Rewrite constant pool references in the method's stackmap table. 2222 // These "structures" are adapted from the StackMapTable_attribute that 2223 // is described in section 4.8.4 of the 6.0 version of the VM spec 2224 // (dated 2005.10.26): 2225 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf 2226 // 2227 // stack_map { 2228 // u2 number_of_entries; 2229 // stack_map_frame entries[number_of_entries]; 2230 // } 2231 // 2232 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table( 2233 methodHandle method, TRAPS) { 2234 2235 if (!method->has_stackmap_table()) { 2236 return; 2237 } 2238 2239 AnnotationArray* stackmap_data = method->stackmap_data(); 2240 address stackmap_p = (address)stackmap_data->adr_at(0); 2241 address stackmap_end = stackmap_p + stackmap_data->length(); 2242 2243 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries"); 2244 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p); 2245 stackmap_p += 2; 2246 2247 RC_TRACE_WITH_THREAD(0x04000000, THREAD, 2248 ("number_of_entries=%u", number_of_entries)); 2249 2250 // walk through each stack_map_frame 2251 u2 calc_number_of_entries = 0; 2252 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) { 2253 // The stack_map_frame structure is a u1 frame_type followed by 2254 // 0 or more bytes of data: 2255 // 2256 // union stack_map_frame { 2257 // same_frame; 2258 // same_locals_1_stack_item_frame; 2259 // same_locals_1_stack_item_frame_extended; 2260 // chop_frame; 2261 // same_frame_extended; 2262 // append_frame; 2263 // full_frame; 2264 // } 2265 2266 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type"); 2267 // The Linux compiler does not like frame_type to be u1 or u2. It 2268 // issues the following warning for the first if-statement below: 2269 // 2270 // "warning: comparison is always true due to limited range of data type" 2271 // 2272 u4 frame_type = *stackmap_p; 2273 stackmap_p++; 2274 2275 // same_frame { 2276 // u1 frame_type = SAME; /* 0-63 */ 2277 // } 2278 if (frame_type >= 0 && frame_type <= 63) { 2279 // nothing more to do for same_frame 2280 } 2281 2282 // same_locals_1_stack_item_frame { 2283 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */ 2284 // verification_type_info stack[1]; 2285 // } 2286 else if (frame_type >= 64 && frame_type <= 127) { 2287 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2288 calc_number_of_entries, frame_type, THREAD); 2289 } 2290 2291 // reserved for future use 2292 else if (frame_type >= 128 && frame_type <= 246) { 2293 // nothing more to do for reserved frame_types 2294 } 2295 2296 // same_locals_1_stack_item_frame_extended { 2297 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */ 2298 // u2 offset_delta; 2299 // verification_type_info stack[1]; 2300 // } 2301 else if (frame_type == 247) { 2302 stackmap_p += 2; 2303 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2304 calc_number_of_entries, frame_type, THREAD); 2305 } 2306 2307 // chop_frame { 2308 // u1 frame_type = CHOP; /* 248-250 */ 2309 // u2 offset_delta; 2310 // } 2311 else if (frame_type >= 248 && frame_type <= 250) { 2312 stackmap_p += 2; 2313 } 2314 2315 // same_frame_extended { 2316 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/ 2317 // u2 offset_delta; 2318 // } 2319 else if (frame_type == 251) { 2320 stackmap_p += 2; 2321 } 2322 2323 // append_frame { 2324 // u1 frame_type = APPEND; /* 252-254 */ 2325 // u2 offset_delta; 2326 // verification_type_info locals[frame_type - 251]; 2327 // } 2328 else if (frame_type >= 252 && frame_type <= 254) { 2329 assert(stackmap_p + 2 <= stackmap_end, 2330 "no room for offset_delta"); 2331 stackmap_p += 2; 2332 u1 len = frame_type - 251; 2333 for (u1 i = 0; i < len; i++) { 2334 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2335 calc_number_of_entries, frame_type, THREAD); 2336 } 2337 } 2338 2339 // full_frame { 2340 // u1 frame_type = FULL_FRAME; /* 255 */ 2341 // u2 offset_delta; 2342 // u2 number_of_locals; 2343 // verification_type_info locals[number_of_locals]; 2344 // u2 number_of_stack_items; 2345 // verification_type_info stack[number_of_stack_items]; 2346 // } 2347 else if (frame_type == 255) { 2348 assert(stackmap_p + 2 + 2 <= stackmap_end, 2349 "no room for smallest full_frame"); 2350 stackmap_p += 2; 2351 2352 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p); 2353 stackmap_p += 2; 2354 2355 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) { 2356 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2357 calc_number_of_entries, frame_type, THREAD); 2358 } 2359 2360 // Use the largest size for the number_of_stack_items, but only get 2361 // the right number of bytes. 2362 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p); 2363 stackmap_p += 2; 2364 2365 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) { 2366 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2367 calc_number_of_entries, frame_type, THREAD); 2368 } 2369 } 2370 } // end while there is a stack_map_frame 2371 assert(number_of_entries == calc_number_of_entries, "sanity check"); 2372 } // end rewrite_cp_refs_in_stack_map_table() 2373 2374 2375 // Rewrite constant pool references in the verification type info 2376 // portion of the method's stackmap table. These "structures" are 2377 // adapted from the StackMapTable_attribute that is described in 2378 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26): 2379 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf 2380 // 2381 // The verification_type_info structure is a u1 tag followed by 0 or 2382 // more bytes of data: 2383 // 2384 // union verification_type_info { 2385 // Top_variable_info; 2386 // Integer_variable_info; 2387 // Float_variable_info; 2388 // Long_variable_info; 2389 // Double_variable_info; 2390 // Null_variable_info; 2391 // UninitializedThis_variable_info; 2392 // Object_variable_info; 2393 // Uninitialized_variable_info; 2394 // } 2395 // 2396 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info( 2397 address& stackmap_p_ref, address stackmap_end, u2 frame_i, 2398 u1 frame_type, TRAPS) { 2399 2400 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag"); 2401 u1 tag = *stackmap_p_ref; 2402 stackmap_p_ref++; 2403 2404 switch (tag) { 2405 // Top_variable_info { 2406 // u1 tag = ITEM_Top; /* 0 */ 2407 // } 2408 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top 2409 case 0: // fall through 2410 2411 // Integer_variable_info { 2412 // u1 tag = ITEM_Integer; /* 1 */ 2413 // } 2414 case ITEM_Integer: // fall through 2415 2416 // Float_variable_info { 2417 // u1 tag = ITEM_Float; /* 2 */ 2418 // } 2419 case ITEM_Float: // fall through 2420 2421 // Double_variable_info { 2422 // u1 tag = ITEM_Double; /* 3 */ 2423 // } 2424 case ITEM_Double: // fall through 2425 2426 // Long_variable_info { 2427 // u1 tag = ITEM_Long; /* 4 */ 2428 // } 2429 case ITEM_Long: // fall through 2430 2431 // Null_variable_info { 2432 // u1 tag = ITEM_Null; /* 5 */ 2433 // } 2434 case ITEM_Null: // fall through 2435 2436 // UninitializedThis_variable_info { 2437 // u1 tag = ITEM_UninitializedThis; /* 6 */ 2438 // } 2439 case ITEM_UninitializedThis: 2440 // nothing more to do for the above tag types 2441 break; 2442 2443 // Object_variable_info { 2444 // u1 tag = ITEM_Object; /* 7 */ 2445 // u2 cpool_index; 2446 // } 2447 case ITEM_Object: 2448 { 2449 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index"); 2450 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref); 2451 u2 new_cp_index = find_new_index(cpool_index); 2452 if (new_cp_index != 0) { 2453 RC_TRACE_WITH_THREAD(0x04000000, THREAD, 2454 ("mapped old cpool_index=%d", cpool_index)); 2455 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index); 2456 cpool_index = new_cp_index; 2457 } 2458 stackmap_p_ref += 2; 2459 2460 RC_TRACE_WITH_THREAD(0x04000000, THREAD, 2461 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i, 2462 frame_type, cpool_index)); 2463 } break; 2464 2465 // Uninitialized_variable_info { 2466 // u1 tag = ITEM_Uninitialized; /* 8 */ 2467 // u2 offset; 2468 // } 2469 case ITEM_Uninitialized: 2470 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset"); 2471 stackmap_p_ref += 2; 2472 break; 2473 2474 default: 2475 RC_TRACE_WITH_THREAD(0x04000000, THREAD, 2476 ("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag)); 2477 ShouldNotReachHere(); 2478 break; 2479 } // end switch (tag) 2480 } // end rewrite_cp_refs_in_verification_type_info() 2481 2482 2483 // Change the constant pool associated with klass scratch_class to 2484 // scratch_cp. If shrink is true, then scratch_cp_length elements 2485 // are copied from scratch_cp to a smaller constant pool and the 2486 // smaller constant pool is associated with scratch_class. 2487 void VM_RedefineClasses::set_new_constant_pool( 2488 ClassLoaderData* loader_data, 2489 instanceKlassHandle scratch_class, constantPoolHandle scratch_cp, 2490 int scratch_cp_length, TRAPS) { 2491 assert(scratch_cp->length() >= scratch_cp_length, "sanity check"); 2492 2493 // scratch_cp is a merged constant pool and has enough space for a 2494 // worst case merge situation. We want to associate the minimum 2495 // sized constant pool with the klass to save space. 2496 constantPoolHandle smaller_cp(THREAD, 2497 ConstantPool::allocate(loader_data, scratch_cp_length, THREAD)); 2498 2499 // preserve version() value in the smaller copy 2500 int version = scratch_cp->version(); 2501 assert(version != 0, "sanity check"); 2502 smaller_cp->set_version(version); 2503 2504 // attach klass to new constant pool 2505 // reference to the cp holder is needed for copy_operands() 2506 smaller_cp->set_pool_holder(scratch_class()); 2507 2508 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD); 2509 scratch_cp = smaller_cp; 2510 2511 // attach new constant pool to klass 2512 scratch_class->set_constants(scratch_cp()); 2513 2514 int i; // for portability 2515 2516 // update each field in klass to use new constant pool indices as needed 2517 for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) { 2518 jshort cur_index = fs.name_index(); 2519 jshort new_index = find_new_index(cur_index); 2520 if (new_index != 0) { 2521 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 2522 ("field-name_index change: %d to %d", cur_index, new_index)); 2523 fs.set_name_index(new_index); 2524 } 2525 cur_index = fs.signature_index(); 2526 new_index = find_new_index(cur_index); 2527 if (new_index != 0) { 2528 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 2529 ("field-signature_index change: %d to %d", cur_index, new_index)); 2530 fs.set_signature_index(new_index); 2531 } 2532 cur_index = fs.initval_index(); 2533 new_index = find_new_index(cur_index); 2534 if (new_index != 0) { 2535 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 2536 ("field-initval_index change: %d to %d", cur_index, new_index)); 2537 fs.set_initval_index(new_index); 2538 } 2539 cur_index = fs.generic_signature_index(); 2540 new_index = find_new_index(cur_index); 2541 if (new_index != 0) { 2542 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 2543 ("field-generic_signature change: %d to %d", cur_index, new_index)); 2544 fs.set_generic_signature_index(new_index); 2545 } 2546 } // end for each field 2547 2548 // Update constant pool indices in the inner classes info to use 2549 // new constant indices as needed. The inner classes info is a 2550 // quadruple: 2551 // (inner_class_info, outer_class_info, inner_name, inner_access_flags) 2552 InnerClassesIterator iter(scratch_class); 2553 for (; !iter.done(); iter.next()) { 2554 int cur_index = iter.inner_class_info_index(); 2555 if (cur_index == 0) { 2556 continue; // JVM spec. allows null inner class refs so skip it 2557 } 2558 int new_index = find_new_index(cur_index); 2559 if (new_index != 0) { 2560 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 2561 ("inner_class_info change: %d to %d", cur_index, new_index)); 2562 iter.set_inner_class_info_index(new_index); 2563 } 2564 cur_index = iter.outer_class_info_index(); 2565 new_index = find_new_index(cur_index); 2566 if (new_index != 0) { 2567 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 2568 ("outer_class_info change: %d to %d", cur_index, new_index)); 2569 iter.set_outer_class_info_index(new_index); 2570 } 2571 cur_index = iter.inner_name_index(); 2572 new_index = find_new_index(cur_index); 2573 if (new_index != 0) { 2574 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 2575 ("inner_name change: %d to %d", cur_index, new_index)); 2576 iter.set_inner_name_index(new_index); 2577 } 2578 } // end for each inner class 2579 2580 // Attach each method in klass to the new constant pool and update 2581 // to use new constant pool indices as needed: 2582 Array<Method*>* methods = scratch_class->methods(); 2583 for (i = methods->length() - 1; i >= 0; i--) { 2584 methodHandle method(THREAD, methods->at(i)); 2585 method->set_constants(scratch_cp()); 2586 2587 int new_index = find_new_index(method->name_index()); 2588 if (new_index != 0) { 2589 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 2590 ("method-name_index change: %d to %d", method->name_index(), 2591 new_index)); 2592 method->set_name_index(new_index); 2593 } 2594 new_index = find_new_index(method->signature_index()); 2595 if (new_index != 0) { 2596 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 2597 ("method-signature_index change: %d to %d", 2598 method->signature_index(), new_index)); 2599 method->set_signature_index(new_index); 2600 } 2601 new_index = find_new_index(method->generic_signature_index()); 2602 if (new_index != 0) { 2603 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 2604 ("method-generic_signature_index change: %d to %d", 2605 method->generic_signature_index(), new_index)); 2606 method->set_generic_signature_index(new_index); 2607 } 2608 2609 // Update constant pool indices in the method's checked exception 2610 // table to use new constant indices as needed. 2611 int cext_length = method->checked_exceptions_length(); 2612 if (cext_length > 0) { 2613 CheckedExceptionElement * cext_table = 2614 method->checked_exceptions_start(); 2615 for (int j = 0; j < cext_length; j++) { 2616 int cur_index = cext_table[j].class_cp_index; 2617 int new_index = find_new_index(cur_index); 2618 if (new_index != 0) { 2619 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 2620 ("cext-class_cp_index change: %d to %d", cur_index, new_index)); 2621 cext_table[j].class_cp_index = (u2)new_index; 2622 } 2623 } // end for each checked exception table entry 2624 } // end if there are checked exception table entries 2625 2626 // Update each catch type index in the method's exception table 2627 // to use new constant pool indices as needed. The exception table 2628 // holds quadruple entries of the form: 2629 // (beg_bci, end_bci, handler_bci, klass_index) 2630 2631 ExceptionTable ex_table(method()); 2632 int ext_length = ex_table.length(); 2633 2634 for (int j = 0; j < ext_length; j ++) { 2635 int cur_index = ex_table.catch_type_index(j); 2636 int new_index = find_new_index(cur_index); 2637 if (new_index != 0) { 2638 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 2639 ("ext-klass_index change: %d to %d", cur_index, new_index)); 2640 ex_table.set_catch_type_index(j, new_index); 2641 } 2642 } // end for each exception table entry 2643 2644 // Update constant pool indices in the method's local variable 2645 // table to use new constant indices as needed. The local variable 2646 // table hold sextuple entries of the form: 2647 // (start_pc, length, name_index, descriptor_index, signature_index, slot) 2648 int lvt_length = method->localvariable_table_length(); 2649 if (lvt_length > 0) { 2650 LocalVariableTableElement * lv_table = 2651 method->localvariable_table_start(); 2652 for (int j = 0; j < lvt_length; j++) { 2653 int cur_index = lv_table[j].name_cp_index; 2654 int new_index = find_new_index(cur_index); 2655 if (new_index != 0) { 2656 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 2657 ("lvt-name_cp_index change: %d to %d", cur_index, new_index)); 2658 lv_table[j].name_cp_index = (u2)new_index; 2659 } 2660 cur_index = lv_table[j].descriptor_cp_index; 2661 new_index = find_new_index(cur_index); 2662 if (new_index != 0) { 2663 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 2664 ("lvt-descriptor_cp_index change: %d to %d", cur_index, 2665 new_index)); 2666 lv_table[j].descriptor_cp_index = (u2)new_index; 2667 } 2668 cur_index = lv_table[j].signature_cp_index; 2669 new_index = find_new_index(cur_index); 2670 if (new_index != 0) { 2671 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 2672 ("lvt-signature_cp_index change: %d to %d", cur_index, new_index)); 2673 lv_table[j].signature_cp_index = (u2)new_index; 2674 } 2675 } // end for each local variable table entry 2676 } // end if there are local variable table entries 2677 2678 rewrite_cp_refs_in_stack_map_table(method, THREAD); 2679 } // end for each method 2680 } // end set_new_constant_pool() 2681 2682 2683 // Unevolving classes may point to methods of the_class directly 2684 // from their constant pool caches, itables, and/or vtables. We 2685 // use the ClassLoaderDataGraph::classes_do() facility and this helper 2686 // to fix up these pointers. 2687 2688 // Adjust cpools and vtables closure 2689 void VM_RedefineClasses::AdjustCpoolCacheAndVtable::do_klass(Klass* k) { 2690 2691 // This is a very busy routine. We don't want too much tracing 2692 // printed out. 2693 bool trace_name_printed = false; 2694 2695 // Very noisy: only enable this call if you are trying to determine 2696 // that a specific class gets found by this routine. 2697 // RC_TRACE macro has an embedded ResourceMark 2698 // RC_TRACE_WITH_THREAD(0x00100000, THREAD, 2699 // ("adjust check: name=%s", k->external_name())); 2700 // trace_name_printed = true; 2701 2702 // If the class being redefined is java.lang.Object, we need to fix all 2703 // array class vtables also 2704 if (k->oop_is_array() && _the_class_oop == SystemDictionary::Object_klass()) { 2705 k->vtable()->adjust_method_entries(_matching_old_methods, 2706 _matching_new_methods, 2707 _matching_methods_length, 2708 &trace_name_printed); 2709 } else if (k->oop_is_instance()) { 2710 HandleMark hm(_thread); 2711 InstanceKlass *ik = InstanceKlass::cast(k); 2712 2713 // HotSpot specific optimization! HotSpot does not currently 2714 // support delegation from the bootstrap class loader to a 2715 // user-defined class loader. This means that if the bootstrap 2716 // class loader is the initiating class loader, then it will also 2717 // be the defining class loader. This also means that classes 2718 // loaded by the bootstrap class loader cannot refer to classes 2719 // loaded by a user-defined class loader. Note: a user-defined 2720 // class loader can delegate to the bootstrap class loader. 2721 // 2722 // If the current class being redefined has a user-defined class 2723 // loader as its defining class loader, then we can skip all 2724 // classes loaded by the bootstrap class loader. 2725 bool is_user_defined = 2726 InstanceKlass::cast(_the_class_oop)->class_loader() != NULL; 2727 if (is_user_defined && ik->class_loader() == NULL) { 2728 return; 2729 } 2730 2731 // Fix the vtable embedded in the_class and subclasses of the_class, 2732 // if one exists. We discard scratch_class and we don't keep an 2733 // InstanceKlass around to hold obsolete methods so we don't have 2734 // any other InstanceKlass embedded vtables to update. The vtable 2735 // holds the Method*s for virtual (but not final) methods. 2736 if (ik->vtable_length() > 0 && ik->is_subtype_of(_the_class_oop)) { 2737 // ik->vtable() creates a wrapper object; rm cleans it up 2738 ResourceMark rm(_thread); 2739 ik->vtable()->adjust_method_entries(_matching_old_methods, 2740 _matching_new_methods, 2741 _matching_methods_length, 2742 &trace_name_printed); 2743 } 2744 2745 // If the current class has an itable and we are either redefining an 2746 // interface or if the current class is a subclass of the_class, then 2747 // we potentially have to fix the itable. If we are redefining an 2748 // interface, then we have to call adjust_method_entries() for 2749 // every InstanceKlass that has an itable since there isn't a 2750 // subclass relationship between an interface and an InstanceKlass. 2751 if (ik->itable_length() > 0 && (_the_class_oop->is_interface() 2752 || ik->is_subclass_of(_the_class_oop))) { 2753 // ik->itable() creates a wrapper object; rm cleans it up 2754 ResourceMark rm(_thread); 2755 ik->itable()->adjust_method_entries(_matching_old_methods, 2756 _matching_new_methods, 2757 _matching_methods_length, 2758 &trace_name_printed); 2759 } 2760 2761 // The constant pools in other classes (other_cp) can refer to 2762 // methods in the_class. We have to update method information in 2763 // other_cp's cache. If other_cp has a previous version, then we 2764 // have to repeat the process for each previous version. The 2765 // constant pool cache holds the Method*s for non-virtual 2766 // methods and for virtual, final methods. 2767 // 2768 // Special case: if the current class is the_class, then new_cp 2769 // has already been attached to the_class and old_cp has already 2770 // been added as a previous version. The new_cp doesn't have any 2771 // cached references to old methods so it doesn't need to be 2772 // updated. We can simply start with the previous version(s) in 2773 // that case. 2774 constantPoolHandle other_cp; 2775 ConstantPoolCache* cp_cache; 2776 2777 if (ik != _the_class_oop) { 2778 // this klass' constant pool cache may need adjustment 2779 other_cp = constantPoolHandle(ik->constants()); 2780 cp_cache = other_cp->cache(); 2781 if (cp_cache != NULL) { 2782 cp_cache->adjust_method_entries(_matching_old_methods, 2783 _matching_new_methods, 2784 _matching_methods_length, 2785 &trace_name_printed); 2786 } 2787 } 2788 { 2789 ResourceMark rm(_thread); 2790 // PreviousVersionInfo objects returned via PreviousVersionWalker 2791 // contain a GrowableArray of handles. We have to clean up the 2792 // GrowableArray _after_ the PreviousVersionWalker destructor 2793 // has destroyed the handles. 2794 { 2795 // the previous versions' constant pool caches may need adjustment 2796 PreviousVersionWalker pvw(ik); 2797 for (PreviousVersionInfo * pv_info = pvw.next_previous_version(); 2798 pv_info != NULL; pv_info = pvw.next_previous_version()) { 2799 other_cp = pv_info->prev_constant_pool_handle(); 2800 cp_cache = other_cp->cache(); 2801 if (cp_cache != NULL) { 2802 cp_cache->adjust_method_entries(_matching_old_methods, 2803 _matching_new_methods, 2804 _matching_methods_length, 2805 &trace_name_printed); 2806 } 2807 } 2808 } // pvw is cleaned up 2809 } // rm is cleaned up 2810 } 2811 } 2812 2813 void VM_RedefineClasses::update_jmethod_ids() { 2814 for (int j = 0; j < _matching_methods_length; ++j) { 2815 Method* old_method = _matching_old_methods[j]; 2816 jmethodID jmid = old_method->find_jmethod_id_or_null(); 2817 if (jmid != NULL) { 2818 // There is a jmethodID, change it to point to the new method 2819 methodHandle new_method_h(_matching_new_methods[j]); 2820 Method::change_method_associated_with_jmethod_id(jmid, new_method_h()); 2821 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j], 2822 "should be replaced"); 2823 } 2824 } 2825 } 2826 2827 void VM_RedefineClasses::check_methods_and_mark_as_obsolete( 2828 BitMap *emcp_methods, int * emcp_method_count_p) { 2829 *emcp_method_count_p = 0; 2830 int obsolete_count = 0; 2831 int old_index = 0; 2832 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) { 2833 Method* old_method = _matching_old_methods[j]; 2834 Method* new_method = _matching_new_methods[j]; 2835 Method* old_array_method; 2836 2837 // Maintain an old_index into the _old_methods array by skipping 2838 // deleted methods 2839 while ((old_array_method = _old_methods->at(old_index)) != old_method) { 2840 ++old_index; 2841 } 2842 2843 if (MethodComparator::methods_EMCP(old_method, new_method)) { 2844 // The EMCP definition from JSR-163 requires the bytecodes to be 2845 // the same with the exception of constant pool indices which may 2846 // differ. However, the constants referred to by those indices 2847 // must be the same. 2848 // 2849 // We use methods_EMCP() for comparison since constant pool 2850 // merging can remove duplicate constant pool entries that were 2851 // present in the old method and removed from the rewritten new 2852 // method. A faster binary comparison function would consider the 2853 // old and new methods to be different when they are actually 2854 // EMCP. 2855 // 2856 // The old and new methods are EMCP and you would think that we 2857 // could get rid of one of them here and now and save some space. 2858 // However, the concept of EMCP only considers the bytecodes and 2859 // the constant pool entries in the comparison. Other things, 2860 // e.g., the line number table (LNT) or the local variable table 2861 // (LVT) don't count in the comparison. So the new (and EMCP) 2862 // method can have a new LNT that we need so we can't just 2863 // overwrite the new method with the old method. 2864 // 2865 // When this routine is called, we have already attached the new 2866 // methods to the_class so the old methods are effectively 2867 // overwritten. However, if an old method is still executing, 2868 // then the old method cannot be collected until sometime after 2869 // the old method call has returned. So the overwriting of old 2870 // methods by new methods will save us space except for those 2871 // (hopefully few) old methods that are still executing. 2872 // 2873 // A method refers to a ConstMethod* and this presents another 2874 // possible avenue to space savings. The ConstMethod* in the 2875 // new method contains possibly new attributes (LNT, LVT, etc). 2876 // At first glance, it seems possible to save space by replacing 2877 // the ConstMethod* in the old method with the ConstMethod* 2878 // from the new method. The old and new methods would share the 2879 // same ConstMethod* and we would save the space occupied by 2880 // the old ConstMethod*. However, the ConstMethod* contains 2881 // a back reference to the containing method. Sharing the 2882 // ConstMethod* between two methods could lead to confusion in 2883 // the code that uses the back reference. This would lead to 2884 // brittle code that could be broken in non-obvious ways now or 2885 // in the future. 2886 // 2887 // Another possibility is to copy the ConstMethod* from the new 2888 // method to the old method and then overwrite the new method with 2889 // the old method. Since the ConstMethod* contains the bytecodes 2890 // for the method embedded in the oop, this option would change 2891 // the bytecodes out from under any threads executing the old 2892 // method and make the thread's bcp invalid. Since EMCP requires 2893 // that the bytecodes be the same modulo constant pool indices, it 2894 // is straight forward to compute the correct new bcp in the new 2895 // ConstMethod* from the old bcp in the old ConstMethod*. The 2896 // time consuming part would be searching all the frames in all 2897 // of the threads to find all of the calls to the old method. 2898 // 2899 // It looks like we will have to live with the limited savings 2900 // that we get from effectively overwriting the old methods 2901 // when the new methods are attached to the_class. 2902 2903 // track which methods are EMCP for add_previous_version() call 2904 emcp_methods->set_bit(old_index); 2905 (*emcp_method_count_p)++; 2906 2907 // An EMCP method is _not_ obsolete. An obsolete method has a 2908 // different jmethodID than the current method. An EMCP method 2909 // has the same jmethodID as the current method. Having the 2910 // same jmethodID for all EMCP versions of a method allows for 2911 // a consistent view of the EMCP methods regardless of which 2912 // EMCP method you happen to have in hand. For example, a 2913 // breakpoint set in one EMCP method will work for all EMCP 2914 // versions of the method including the current one. 2915 } else { 2916 // mark obsolete methods as such 2917 old_method->set_is_obsolete(); 2918 obsolete_count++; 2919 2920 // obsolete methods need a unique idnum 2921 u2 num = InstanceKlass::cast(_the_class_oop)->next_method_idnum(); 2922 if (num != ConstMethod::UNSET_IDNUM) { 2923 // u2 old_num = old_method->method_idnum(); 2924 old_method->set_method_idnum(num); 2925 // TO DO: attach obsolete annotations to obsolete method's new idnum 2926 } 2927 // With tracing we try not to "yack" too much. The position of 2928 // this trace assumes there are fewer obsolete methods than 2929 // EMCP methods. 2930 RC_TRACE(0x00000100, ("mark %s(%s) as obsolete", 2931 old_method->name()->as_C_string(), 2932 old_method->signature()->as_C_string())); 2933 } 2934 old_method->set_is_old(); 2935 } 2936 for (int i = 0; i < _deleted_methods_length; ++i) { 2937 Method* old_method = _deleted_methods[i]; 2938 2939 assert(old_method->vtable_index() < 0, 2940 "cannot delete methods with vtable entries");; 2941 2942 // Mark all deleted methods as old and obsolete 2943 old_method->set_is_old(); 2944 old_method->set_is_obsolete(); 2945 ++obsolete_count; 2946 // With tracing we try not to "yack" too much. The position of 2947 // this trace assumes there are fewer obsolete methods than 2948 // EMCP methods. 2949 RC_TRACE(0x00000100, ("mark deleted %s(%s) as obsolete", 2950 old_method->name()->as_C_string(), 2951 old_method->signature()->as_C_string())); 2952 } 2953 assert((*emcp_method_count_p + obsolete_count) == _old_methods->length(), 2954 "sanity check"); 2955 RC_TRACE(0x00000100, ("EMCP_cnt=%d, obsolete_cnt=%d", *emcp_method_count_p, 2956 obsolete_count)); 2957 } 2958 2959 // This internal class transfers the native function registration from old methods 2960 // to new methods. It is designed to handle both the simple case of unchanged 2961 // native methods and the complex cases of native method prefixes being added and/or 2962 // removed. 2963 // It expects only to be used during the VM_RedefineClasses op (a safepoint). 2964 // 2965 // This class is used after the new methods have been installed in "the_class". 2966 // 2967 // So, for example, the following must be handled. Where 'm' is a method and 2968 // a number followed by an underscore is a prefix. 2969 // 2970 // Old Name New Name 2971 // Simple transfer to new method m -> m 2972 // Add prefix m -> 1_m 2973 // Remove prefix 1_m -> m 2974 // Simultaneous add of prefixes m -> 3_2_1_m 2975 // Simultaneous removal of prefixes 3_2_1_m -> m 2976 // Simultaneous add and remove 1_m -> 2_m 2977 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m 2978 // 2979 class TransferNativeFunctionRegistration { 2980 private: 2981 instanceKlassHandle the_class; 2982 int prefix_count; 2983 char** prefixes; 2984 2985 // Recursively search the binary tree of possibly prefixed method names. 2986 // Iteration could be used if all agents were well behaved. Full tree walk is 2987 // more resilent to agents not cleaning up intermediate methods. 2988 // Branch at each depth in the binary tree is: 2989 // (1) without the prefix. 2990 // (2) with the prefix. 2991 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...) 2992 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len, 2993 Symbol* signature) { 2994 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len); 2995 if (name_symbol != NULL) { 2996 Method* method = the_class()->lookup_method(name_symbol, signature); 2997 if (method != NULL) { 2998 // Even if prefixed, intermediate methods must exist. 2999 if (method->is_native()) { 3000 // Wahoo, we found a (possibly prefixed) version of the method, return it. 3001 return method; 3002 } 3003 if (depth < prefix_count) { 3004 // Try applying further prefixes (other than this one). 3005 method = search_prefix_name_space(depth+1, name_str, name_len, signature); 3006 if (method != NULL) { 3007 return method; // found 3008 } 3009 3010 // Try adding this prefix to the method name and see if it matches 3011 // another method name. 3012 char* prefix = prefixes[depth]; 3013 size_t prefix_len = strlen(prefix); 3014 size_t trial_len = name_len + prefix_len; 3015 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1); 3016 strcpy(trial_name_str, prefix); 3017 strcat(trial_name_str, name_str); 3018 method = search_prefix_name_space(depth+1, trial_name_str, trial_len, 3019 signature); 3020 if (method != NULL) { 3021 // If found along this branch, it was prefixed, mark as such 3022 method->set_is_prefixed_native(); 3023 return method; // found 3024 } 3025 } 3026 } 3027 } 3028 return NULL; // This whole branch bore nothing 3029 } 3030 3031 // Return the method name with old prefixes stripped away. 3032 char* method_name_without_prefixes(Method* method) { 3033 Symbol* name = method->name(); 3034 char* name_str = name->as_utf8(); 3035 3036 // Old prefixing may be defunct, strip prefixes, if any. 3037 for (int i = prefix_count-1; i >= 0; i--) { 3038 char* prefix = prefixes[i]; 3039 size_t prefix_len = strlen(prefix); 3040 if (strncmp(prefix, name_str, prefix_len) == 0) { 3041 name_str += prefix_len; 3042 } 3043 } 3044 return name_str; 3045 } 3046 3047 // Strip any prefixes off the old native method, then try to find a 3048 // (possibly prefixed) new native that matches it. 3049 Method* strip_and_search_for_new_native(Method* method) { 3050 ResourceMark rm; 3051 char* name_str = method_name_without_prefixes(method); 3052 return search_prefix_name_space(0, name_str, strlen(name_str), 3053 method->signature()); 3054 } 3055 3056 public: 3057 3058 // Construct a native method transfer processor for this class. 3059 TransferNativeFunctionRegistration(instanceKlassHandle _the_class) { 3060 assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); 3061 3062 the_class = _the_class; 3063 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count); 3064 } 3065 3066 // Attempt to transfer any of the old or deleted methods that are native 3067 void transfer_registrations(Method** old_methods, int methods_length) { 3068 for (int j = 0; j < methods_length; j++) { 3069 Method* old_method = old_methods[j]; 3070 3071 if (old_method->is_native() && old_method->has_native_function()) { 3072 Method* new_method = strip_and_search_for_new_native(old_method); 3073 if (new_method != NULL) { 3074 // Actually set the native function in the new method. 3075 // Redefine does not send events (except CFLH), certainly not this 3076 // behind the scenes re-registration. 3077 new_method->set_native_function(old_method->native_function(), 3078 !Method::native_bind_event_is_interesting); 3079 } 3080 } 3081 } 3082 } 3083 }; 3084 3085 // Don't lose the association between a native method and its JNI function. 3086 void VM_RedefineClasses::transfer_old_native_function_registrations(instanceKlassHandle the_class) { 3087 TransferNativeFunctionRegistration transfer(the_class); 3088 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length); 3089 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length); 3090 } 3091 3092 // Deoptimize all compiled code that depends on this class. 3093 // 3094 // If the can_redefine_classes capability is obtained in the onload 3095 // phase then the compiler has recorded all dependencies from startup. 3096 // In that case we need only deoptimize and throw away all compiled code 3097 // that depends on the class. 3098 // 3099 // If can_redefine_classes is obtained sometime after the onload 3100 // phase then the dependency information may be incomplete. In that case 3101 // the first call to RedefineClasses causes all compiled code to be 3102 // thrown away. As can_redefine_classes has been obtained then 3103 // all future compilations will record dependencies so second and 3104 // subsequent calls to RedefineClasses need only throw away code 3105 // that depends on the class. 3106 // 3107 void VM_RedefineClasses::flush_dependent_code(instanceKlassHandle k_h, TRAPS) { 3108 assert_locked_or_safepoint(Compile_lock); 3109 3110 // All dependencies have been recorded from startup or this is a second or 3111 // subsequent use of RedefineClasses 3112 if (JvmtiExport::all_dependencies_are_recorded()) { 3113 Universe::flush_evol_dependents_on(k_h); 3114 } else { 3115 CodeCache::mark_all_nmethods_for_deoptimization(); 3116 3117 ResourceMark rm(THREAD); 3118 DeoptimizationMarker dm; 3119 3120 // Deoptimize all activations depending on marked nmethods 3121 Deoptimization::deoptimize_dependents(); 3122 3123 // Make the dependent methods not entrant (in VM_Deoptimize they are made zombies) 3124 CodeCache::make_marked_nmethods_not_entrant(); 3125 3126 // From now on we know that the dependency information is complete 3127 JvmtiExport::set_all_dependencies_are_recorded(true); 3128 } 3129 } 3130 3131 void VM_RedefineClasses::compute_added_deleted_matching_methods() { 3132 Method* old_method; 3133 Method* new_method; 3134 3135 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 3136 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 3137 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length()); 3138 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 3139 3140 _matching_methods_length = 0; 3141 _deleted_methods_length = 0; 3142 _added_methods_length = 0; 3143 3144 int nj = 0; 3145 int oj = 0; 3146 while (true) { 3147 if (oj >= _old_methods->length()) { 3148 if (nj >= _new_methods->length()) { 3149 break; // we've looked at everything, done 3150 } 3151 // New method at the end 3152 new_method = _new_methods->at(nj); 3153 _added_methods[_added_methods_length++] = new_method; 3154 ++nj; 3155 } else if (nj >= _new_methods->length()) { 3156 // Old method, at the end, is deleted 3157 old_method = _old_methods->at(oj); 3158 _deleted_methods[_deleted_methods_length++] = old_method; 3159 ++oj; 3160 } else { 3161 old_method = _old_methods->at(oj); 3162 new_method = _new_methods->at(nj); 3163 if (old_method->name() == new_method->name()) { 3164 if (old_method->signature() == new_method->signature()) { 3165 _matching_old_methods[_matching_methods_length ] = old_method; 3166 _matching_new_methods[_matching_methods_length++] = new_method; 3167 ++nj; 3168 ++oj; 3169 } else { 3170 // added overloaded have already been moved to the end, 3171 // so this is a deleted overloaded method 3172 _deleted_methods[_deleted_methods_length++] = old_method; 3173 ++oj; 3174 } 3175 } else { // names don't match 3176 if (old_method->name()->fast_compare(new_method->name()) > 0) { 3177 // new method 3178 _added_methods[_added_methods_length++] = new_method; 3179 ++nj; 3180 } else { 3181 // deleted method 3182 _deleted_methods[_deleted_methods_length++] = old_method; 3183 ++oj; 3184 } 3185 } 3186 } 3187 } 3188 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity"); 3189 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity"); 3190 } 3191 3192 3193 void VM_RedefineClasses::swap_annotations(instanceKlassHandle the_class, 3194 instanceKlassHandle scratch_class) { 3195 // Since there is currently no rewriting of type annotations indexes 3196 // into the CP, we null out type annotations on scratch_class before 3197 // we swap annotations with the_class rather than facing the 3198 // possibility of shipping annotations with broken indexes to 3199 // Java-land. 3200 ClassLoaderData* loader_data = scratch_class->class_loader_data(); 3201 AnnotationArray* new_class_type_annotations = scratch_class->class_type_annotations(); 3202 if (new_class_type_annotations != NULL) { 3203 MetadataFactory::free_array<u1>(loader_data, new_class_type_annotations); 3204 scratch_class->annotations()->set_class_type_annotations(NULL); 3205 } 3206 Array<AnnotationArray*>* new_field_type_annotations = scratch_class->fields_type_annotations(); 3207 if (new_field_type_annotations != NULL) { 3208 Annotations::free_contents(loader_data, new_field_type_annotations); 3209 scratch_class->annotations()->set_fields_type_annotations(NULL); 3210 } 3211 3212 // Swap annotation fields values 3213 Annotations* old_annotations = the_class->annotations(); 3214 the_class->set_annotations(scratch_class->annotations()); 3215 scratch_class->set_annotations(old_annotations); 3216 } 3217 3218 3219 // Install the redefinition of a class: 3220 // - house keeping (flushing breakpoints and caches, deoptimizing 3221 // dependent compiled code) 3222 // - replacing parts in the_class with parts from scratch_class 3223 // - adding a weak reference to track the obsolete but interesting 3224 // parts of the_class 3225 // - adjusting constant pool caches and vtables in other classes 3226 // that refer to methods in the_class. These adjustments use the 3227 // ClassLoaderDataGraph::classes_do() facility which only allows 3228 // a helper method to be specified. The interesting parameters 3229 // that we would like to pass to the helper method are saved in 3230 // static global fields in the VM operation. 3231 void VM_RedefineClasses::redefine_single_class(jclass the_jclass, 3232 Klass* scratch_class_oop, TRAPS) { 3233 3234 HandleMark hm(THREAD); // make sure handles from this call are freed 3235 RC_TIMER_START(_timer_rsc_phase1); 3236 3237 instanceKlassHandle scratch_class(scratch_class_oop); 3238 3239 oop the_class_mirror = JNIHandles::resolve_non_null(the_jclass); 3240 Klass* the_class_oop = java_lang_Class::as_Klass(the_class_mirror); 3241 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop); 3242 3243 // Remove all breakpoints in methods of this class 3244 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints(); 3245 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class_oop); 3246 3247 // Deoptimize all compiled code that depends on this class 3248 flush_dependent_code(the_class, THREAD); 3249 3250 _old_methods = the_class->methods(); 3251 _new_methods = scratch_class->methods(); 3252 _the_class_oop = the_class_oop; 3253 compute_added_deleted_matching_methods(); 3254 update_jmethod_ids(); 3255 3256 // Attach new constant pool to the original klass. The original 3257 // klass still refers to the old constant pool (for now). 3258 scratch_class->constants()->set_pool_holder(the_class()); 3259 3260 #if 0 3261 // In theory, with constant pool merging in place we should be able 3262 // to save space by using the new, merged constant pool in place of 3263 // the old constant pool(s). By "pool(s)" I mean the constant pool in 3264 // the klass version we are replacing now and any constant pool(s) in 3265 // previous versions of klass. Nice theory, doesn't work in practice. 3266 // When this code is enabled, even simple programs throw NullPointer 3267 // exceptions. I'm guessing that this is caused by some constant pool 3268 // cache difference between the new, merged constant pool and the 3269 // constant pool that was just being used by the klass. I'm keeping 3270 // this code around to archive the idea, but the code has to remain 3271 // disabled for now. 3272 3273 // Attach each old method to the new constant pool. This can be 3274 // done here since we are past the bytecode verification and 3275 // constant pool optimization phases. 3276 for (int i = _old_methods->length() - 1; i >= 0; i--) { 3277 Method* method = _old_methods->at(i); 3278 method->set_constants(scratch_class->constants()); 3279 } 3280 3281 { 3282 // walk all previous versions of the klass 3283 InstanceKlass *ik = (InstanceKlass *)the_class(); 3284 PreviousVersionWalker pvw(ik); 3285 instanceKlassHandle ikh; 3286 do { 3287 ikh = pvw.next_previous_version(); 3288 if (!ikh.is_null()) { 3289 ik = ikh(); 3290 3291 // attach previous version of klass to the new constant pool 3292 ik->set_constants(scratch_class->constants()); 3293 3294 // Attach each method in the previous version of klass to the 3295 // new constant pool 3296 Array<Method*>* prev_methods = ik->methods(); 3297 for (int i = prev_methods->length() - 1; i >= 0; i--) { 3298 Method* method = prev_methods->at(i); 3299 method->set_constants(scratch_class->constants()); 3300 } 3301 } 3302 } while (!ikh.is_null()); 3303 } 3304 #endif 3305 3306 // Replace methods and constantpool 3307 the_class->set_methods(_new_methods); 3308 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods, 3309 // and to be able to undo operation easily. 3310 3311 ConstantPool* old_constants = the_class->constants(); 3312 the_class->set_constants(scratch_class->constants()); 3313 scratch_class->set_constants(old_constants); // See the previous comment. 3314 #if 0 3315 // We are swapping the guts of "the new class" with the guts of "the 3316 // class". Since the old constant pool has just been attached to "the 3317 // new class", it seems logical to set the pool holder in the old 3318 // constant pool also. However, doing this will change the observable 3319 // class hierarchy for any old methods that are still executing. A 3320 // method can query the identity of its "holder" and this query uses 3321 // the method's constant pool link to find the holder. The change in 3322 // holding class from "the class" to "the new class" can confuse 3323 // things. 3324 // 3325 // Setting the old constant pool's holder will also cause 3326 // verification done during vtable initialization below to fail. 3327 // During vtable initialization, the vtable's class is verified to be 3328 // a subtype of the method's holder. The vtable's class is "the 3329 // class" and the method's holder is gotten from the constant pool 3330 // link in the method itself. For "the class"'s directly implemented 3331 // methods, the method holder is "the class" itself (as gotten from 3332 // the new constant pool). The check works fine in this case. The 3333 // check also works fine for methods inherited from super classes. 3334 // 3335 // Miranda methods are a little more complicated. A miranda method is 3336 // provided by an interface when the class implementing the interface 3337 // does not provide its own method. These interfaces are implemented 3338 // internally as an InstanceKlass. These special instanceKlasses 3339 // share the constant pool of the class that "implements" the 3340 // interface. By sharing the constant pool, the method holder of a 3341 // miranda method is the class that "implements" the interface. In a 3342 // non-redefine situation, the subtype check works fine. However, if 3343 // the old constant pool's pool holder is modified, then the check 3344 // fails because there is no class hierarchy relationship between the 3345 // vtable's class and "the new class". 3346 3347 old_constants->set_pool_holder(scratch_class()); 3348 #endif 3349 3350 // track which methods are EMCP for add_previous_version() call below 3351 BitMap emcp_methods(_old_methods->length()); 3352 int emcp_method_count = 0; 3353 emcp_methods.clear(); // clears 0..(length() - 1) 3354 check_methods_and_mark_as_obsolete(&emcp_methods, &emcp_method_count); 3355 transfer_old_native_function_registrations(the_class); 3356 3357 // The class file bytes from before any retransformable agents mucked 3358 // with them was cached on the scratch class, move to the_class. 3359 // Note: we still want to do this if nothing needed caching since it 3360 // should get cleared in the_class too. 3361 if (the_class->get_cached_class_file_bytes() == 0) { 3362 // the_class doesn't have a cache yet so copy it 3363 the_class->set_cached_class_file(scratch_class->get_cached_class_file()); 3364 } 3365 #ifndef PRODUCT 3366 else { 3367 assert(the_class->get_cached_class_file_bytes() == 3368 scratch_class->get_cached_class_file_bytes(), "cache ptrs must match"); 3369 assert(the_class->get_cached_class_file_len() == 3370 scratch_class->get_cached_class_file_len(), "cache lens must match"); 3371 } 3372 #endif 3373 3374 // NULL out in scratch class to not delete twice. The class to be redefined 3375 // always owns these bytes. 3376 scratch_class->set_cached_class_file(NULL); 3377 3378 // Replace inner_classes 3379 Array<u2>* old_inner_classes = the_class->inner_classes(); 3380 the_class->set_inner_classes(scratch_class->inner_classes()); 3381 scratch_class->set_inner_classes(old_inner_classes); 3382 3383 // Initialize the vtable and interface table after 3384 // methods have been rewritten 3385 { 3386 ResourceMark rm(THREAD); 3387 // no exception should happen here since we explicitly 3388 // do not check loader constraints. 3389 // compare_and_normalize_class_versions has already checked: 3390 // - classloaders unchanged, signatures unchanged 3391 // - all instanceKlasses for redefined classes reused & contents updated 3392 the_class->vtable()->initialize_vtable(false, THREAD); 3393 the_class->itable()->initialize_itable(false, THREAD); 3394 assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())), "redefine exception"); 3395 } 3396 3397 // Leave arrays of jmethodIDs and itable index cache unchanged 3398 3399 // Copy the "source file name" attribute from new class version 3400 the_class->set_source_file_name_index( 3401 scratch_class->source_file_name_index()); 3402 3403 // Copy the "source debug extension" attribute from new class version 3404 the_class->set_source_debug_extension( 3405 scratch_class->source_debug_extension(), 3406 scratch_class->source_debug_extension() == NULL ? 0 : 3407 (int)strlen(scratch_class->source_debug_extension())); 3408 3409 // Use of javac -g could be different in the old and the new 3410 if (scratch_class->access_flags().has_localvariable_table() != 3411 the_class->access_flags().has_localvariable_table()) { 3412 3413 AccessFlags flags = the_class->access_flags(); 3414 if (scratch_class->access_flags().has_localvariable_table()) { 3415 flags.set_has_localvariable_table(); 3416 } else { 3417 flags.clear_has_localvariable_table(); 3418 } 3419 the_class->set_access_flags(flags); 3420 } 3421 3422 swap_annotations(the_class, scratch_class); 3423 3424 // Replace minor version number of class file 3425 u2 old_minor_version = the_class->minor_version(); 3426 the_class->set_minor_version(scratch_class->minor_version()); 3427 scratch_class->set_minor_version(old_minor_version); 3428 3429 // Replace major version number of class file 3430 u2 old_major_version = the_class->major_version(); 3431 the_class->set_major_version(scratch_class->major_version()); 3432 scratch_class->set_major_version(old_major_version); 3433 3434 // Replace CP indexes for class and name+type of enclosing method 3435 u2 old_class_idx = the_class->enclosing_method_class_index(); 3436 u2 old_method_idx = the_class->enclosing_method_method_index(); 3437 the_class->set_enclosing_method_indices( 3438 scratch_class->enclosing_method_class_index(), 3439 scratch_class->enclosing_method_method_index()); 3440 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx); 3441 3442 // keep track of previous versions of this class 3443 the_class->add_previous_version(scratch_class, &emcp_methods, 3444 emcp_method_count); 3445 3446 RC_TIMER_STOP(_timer_rsc_phase1); 3447 RC_TIMER_START(_timer_rsc_phase2); 3448 3449 // Adjust constantpool caches and vtables for all classes 3450 // that reference methods of the evolved class. 3451 AdjustCpoolCacheAndVtable adjust_cpool_cache_and_vtable(THREAD); 3452 ClassLoaderDataGraph::classes_do(&adjust_cpool_cache_and_vtable); 3453 3454 // JSR-292 support 3455 MemberNameTable* mnt = the_class->member_names(); 3456 if (mnt != NULL) { 3457 bool trace_name_printed = false; 3458 mnt->adjust_method_entries(_matching_old_methods, 3459 _matching_new_methods, 3460 _matching_methods_length, 3461 &trace_name_printed); 3462 } 3463 3464 // Fix Resolution Error table also to remove old constant pools 3465 SystemDictionary::delete_resolution_error(old_constants); 3466 3467 if (the_class->oop_map_cache() != NULL) { 3468 // Flush references to any obsolete methods from the oop map cache 3469 // so that obsolete methods are not pinned. 3470 the_class->oop_map_cache()->flush_obsolete_entries(); 3471 } 3472 3473 // increment the classRedefinedCount field in the_class and in any 3474 // direct and indirect subclasses of the_class 3475 increment_class_counter((InstanceKlass *)the_class(), THREAD); 3476 3477 // RC_TRACE macro has an embedded ResourceMark 3478 RC_TRACE_WITH_THREAD(0x00000001, THREAD, 3479 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)", 3480 the_class->external_name(), 3481 java_lang_Class::classRedefinedCount(the_class_mirror), 3482 os::available_memory() >> 10)); 3483 3484 RC_TIMER_STOP(_timer_rsc_phase2); 3485 } // end redefine_single_class() 3486 3487 3488 // Increment the classRedefinedCount field in the specific InstanceKlass 3489 // and in all direct and indirect subclasses. 3490 void VM_RedefineClasses::increment_class_counter(InstanceKlass *ik, TRAPS) { 3491 oop class_mirror = ik->java_mirror(); 3492 Klass* class_oop = java_lang_Class::as_Klass(class_mirror); 3493 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1; 3494 java_lang_Class::set_classRedefinedCount(class_mirror, new_count); 3495 3496 if (class_oop != _the_class_oop) { 3497 // _the_class_oop count is printed at end of redefine_single_class() 3498 RC_TRACE_WITH_THREAD(0x00000008, THREAD, 3499 ("updated count in subclass=%s to %d", ik->external_name(), new_count)); 3500 } 3501 3502 for (Klass *subk = ik->subklass(); subk != NULL; 3503 subk = subk->next_sibling()) { 3504 if (subk->oop_is_instance()) { 3505 // Only update instanceKlasses 3506 InstanceKlass *subik = (InstanceKlass*)subk; 3507 // recursively do subclasses of the current subclass 3508 increment_class_counter(subik, THREAD); 3509 } 3510 } 3511 } 3512 3513 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) { 3514 bool no_old_methods = true; // be optimistic 3515 3516 // Both array and instance classes have vtables. 3517 // a vtable should never contain old or obsolete methods 3518 ResourceMark rm(_thread); 3519 if (k->vtable_length() > 0 && 3520 !k->vtable()->check_no_old_or_obsolete_entries()) { 3521 if (RC_TRACE_ENABLED(0x00004000)) { 3522 RC_TRACE_WITH_THREAD(0x00004000, _thread, 3523 ("klassVtable::check_no_old_or_obsolete_entries failure" 3524 " -- OLD or OBSOLETE method found -- class: %s", 3525 k->signature_name())); 3526 k->vtable()->dump_vtable(); 3527 } 3528 no_old_methods = false; 3529 } 3530 3531 if (k->oop_is_instance()) { 3532 HandleMark hm(_thread); 3533 InstanceKlass *ik = InstanceKlass::cast(k); 3534 3535 // an itable should never contain old or obsolete methods 3536 if (ik->itable_length() > 0 && 3537 !ik->itable()->check_no_old_or_obsolete_entries()) { 3538 if (RC_TRACE_ENABLED(0x00004000)) { 3539 RC_TRACE_WITH_THREAD(0x00004000, _thread, 3540 ("klassItable::check_no_old_or_obsolete_entries failure" 3541 " -- OLD or OBSOLETE method found -- class: %s", 3542 ik->signature_name())); 3543 ik->itable()->dump_itable(); 3544 } 3545 no_old_methods = false; 3546 } 3547 3548 // the constant pool cache should never contain old or obsolete methods 3549 if (ik->constants() != NULL && 3550 ik->constants()->cache() != NULL && 3551 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) { 3552 if (RC_TRACE_ENABLED(0x00004000)) { 3553 RC_TRACE_WITH_THREAD(0x00004000, _thread, 3554 ("cp-cache::check_no_old_or_obsolete_entries failure" 3555 " -- OLD or OBSOLETE method found -- class: %s", 3556 ik->signature_name())); 3557 ik->constants()->cache()->dump_cache(); 3558 } 3559 no_old_methods = false; 3560 } 3561 } 3562 3563 // print and fail guarantee if old methods are found. 3564 if (!no_old_methods) { 3565 if (RC_TRACE_ENABLED(0x00004000)) { 3566 dump_methods(); 3567 } else { 3568 tty->print_cr("INFO: use the '-XX:TraceRedefineClasses=16384' option " 3569 "to see more info about the following guarantee() failure."); 3570 } 3571 guarantee(false, "OLD and/or OBSOLETE method(s) found"); 3572 } 3573 } 3574 3575 3576 void VM_RedefineClasses::dump_methods() { 3577 int j; 3578 RC_TRACE(0x00004000, ("_old_methods --")); 3579 for (j = 0; j < _old_methods->length(); ++j) { 3580 Method* m = _old_methods->at(j); 3581 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index())); 3582 m->access_flags().print_on(tty); 3583 tty->print(" -- "); 3584 m->print_name(tty); 3585 tty->cr(); 3586 } 3587 RC_TRACE(0x00004000, ("_new_methods --")); 3588 for (j = 0; j < _new_methods->length(); ++j) { 3589 Method* m = _new_methods->at(j); 3590 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index())); 3591 m->access_flags().print_on(tty); 3592 tty->print(" -- "); 3593 m->print_name(tty); 3594 tty->cr(); 3595 } 3596 RC_TRACE(0x00004000, ("_matching_(old/new)_methods --")); 3597 for (j = 0; j < _matching_methods_length; ++j) { 3598 Method* m = _matching_old_methods[j]; 3599 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index())); 3600 m->access_flags().print_on(tty); 3601 tty->print(" -- "); 3602 m->print_name(tty); 3603 tty->cr(); 3604 m = _matching_new_methods[j]; 3605 RC_TRACE_NO_CR(0x00004000, (" (%5d) ", m->vtable_index())); 3606 m->access_flags().print_on(tty); 3607 tty->cr(); 3608 } 3609 RC_TRACE(0x00004000, ("_deleted_methods --")); 3610 for (j = 0; j < _deleted_methods_length; ++j) { 3611 Method* m = _deleted_methods[j]; 3612 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index())); 3613 m->access_flags().print_on(tty); 3614 tty->print(" -- "); 3615 m->print_name(tty); 3616 tty->cr(); 3617 } 3618 RC_TRACE(0x00004000, ("_added_methods --")); 3619 for (j = 0; j < _added_methods_length; ++j) { 3620 Method* m = _added_methods[j]; 3621 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index())); 3622 m->access_flags().print_on(tty); 3623 tty->print(" -- "); 3624 m->print_name(tty); 3625 tty->cr(); 3626 } 3627 }