1 /* 2 * Copyright (c) 2003, 2015, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "classfile/metadataOnStackMark.hpp" 27 #include "classfile/systemDictionary.hpp" 28 #include "classfile/verifier.hpp" 29 #include "code/codeCache.hpp" 30 #include "compiler/compileBroker.hpp" 31 #include "interpreter/oopMapCache.hpp" 32 #include "interpreter/rewriter.hpp" 33 #include "memory/gcLocker.hpp" 34 #include "memory/metadataFactory.hpp" 35 #include "memory/metaspaceShared.hpp" 36 #include "memory/universe.inline.hpp" 37 #include "oops/fieldStreams.hpp" 38 #include "oops/klassVtable.hpp" 39 #include "prims/jvmtiImpl.hpp" 40 #include "prims/jvmtiRedefineClasses.hpp" 41 #include "prims/methodComparator.hpp" 42 #include "runtime/deoptimization.hpp" 43 #include "runtime/relocator.hpp" 44 #include "utilities/bitMap.inline.hpp" 45 46 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC 47 48 Array<Method*>* VM_RedefineClasses::_old_methods = NULL; 49 Array<Method*>* VM_RedefineClasses::_new_methods = NULL; 50 Method** VM_RedefineClasses::_matching_old_methods = NULL; 51 Method** VM_RedefineClasses::_matching_new_methods = NULL; 52 Method** VM_RedefineClasses::_deleted_methods = NULL; 53 Method** VM_RedefineClasses::_added_methods = NULL; 54 int VM_RedefineClasses::_matching_methods_length = 0; 55 int VM_RedefineClasses::_deleted_methods_length = 0; 56 int VM_RedefineClasses::_added_methods_length = 0; 57 Klass* VM_RedefineClasses::_the_class_oop = NULL; 58 59 60 VM_RedefineClasses::VM_RedefineClasses(jint class_count, 61 const jvmtiClassDefinition *class_defs, 62 JvmtiClassLoadKind class_load_kind) { 63 _class_count = class_count; 64 _class_defs = class_defs; 65 _class_load_kind = class_load_kind; 66 _res = JVMTI_ERROR_NONE; 67 } 68 69 bool VM_RedefineClasses::doit_prologue() { 70 if (_class_count == 0) { 71 _res = JVMTI_ERROR_NONE; 72 return false; 73 } 74 if (_class_defs == NULL) { 75 _res = JVMTI_ERROR_NULL_POINTER; 76 return false; 77 } 78 for (int i = 0; i < _class_count; i++) { 79 if (_class_defs[i].klass == NULL) { 80 _res = JVMTI_ERROR_INVALID_CLASS; 81 return false; 82 } 83 if (_class_defs[i].class_byte_count == 0) { 84 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT; 85 return false; 86 } 87 if (_class_defs[i].class_bytes == NULL) { 88 _res = JVMTI_ERROR_NULL_POINTER; 89 return false; 90 } 91 } 92 93 // Start timer after all the sanity checks; not quite accurate, but 94 // better than adding a bunch of stop() calls. 95 RC_TIMER_START(_timer_vm_op_prologue); 96 97 // We first load new class versions in the prologue, because somewhere down the 98 // call chain it is required that the current thread is a Java thread. 99 _res = load_new_class_versions(Thread::current()); 100 if (_res != JVMTI_ERROR_NONE) { 101 // free any successfully created classes, since none are redefined 102 for (int i = 0; i < _class_count; i++) { 103 if (_scratch_classes[i] != NULL) { 104 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data(); 105 // Free the memory for this class at class unloading time. Not before 106 // because CMS might think this is still live. 107 cld->add_to_deallocate_list((InstanceKlass*)_scratch_classes[i]); 108 } 109 } 110 // Free os::malloc allocated memory in load_new_class_version. 111 os::free(_scratch_classes); 112 RC_TIMER_STOP(_timer_vm_op_prologue); 113 return false; 114 } 115 116 RC_TIMER_STOP(_timer_vm_op_prologue); 117 return true; 118 } 119 120 void VM_RedefineClasses::doit() { 121 Thread *thread = Thread::current(); 122 123 if (UseSharedSpaces) { 124 // Sharing is enabled so we remap the shared readonly space to 125 // shared readwrite, private just in case we need to redefine 126 // a shared class. We do the remap during the doit() phase of 127 // the safepoint to be safer. 128 if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) { 129 RC_TRACE_WITH_THREAD(0x00000001, thread, 130 ("failed to remap shared readonly space to readwrite, private")); 131 _res = JVMTI_ERROR_INTERNAL; 132 return; 133 } 134 } 135 136 // Mark methods seen on stack and everywhere else so old methods are not 137 // cleaned up if they're on the stack. 138 MetadataOnStackMark md_on_stack(true); 139 HandleMark hm(thread); // make sure any handles created are deleted 140 // before the stack walk again. 141 142 for (int i = 0; i < _class_count; i++) { 143 redefine_single_class(_class_defs[i].klass, _scratch_classes[i], thread); 144 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data(); 145 // Free the memory for this class at class unloading time. Not before 146 // because CMS might think this is still live. 147 cld->add_to_deallocate_list((InstanceKlass*)_scratch_classes[i]); 148 _scratch_classes[i] = NULL; 149 } 150 151 // Disable any dependent concurrent compilations 152 SystemDictionary::notice_modification(); 153 154 // Set flag indicating that some invariants are no longer true. 155 // See jvmtiExport.hpp for detailed explanation. 156 JvmtiExport::set_has_redefined_a_class(); 157 158 // check_class() is optionally called for product bits, but is 159 // always called for non-product bits. 160 #ifdef PRODUCT 161 if (RC_TRACE_ENABLED(0x00004000)) { 162 #endif 163 RC_TRACE_WITH_THREAD(0x00004000, thread, ("calling check_class")); 164 CheckClass check_class(thread); 165 ClassLoaderDataGraph::classes_do(&check_class); 166 #ifdef PRODUCT 167 } 168 #endif 169 } 170 171 void VM_RedefineClasses::doit_epilogue() { 172 // Free os::malloc allocated memory. 173 os::free(_scratch_classes); 174 175 if (RC_TRACE_ENABLED(0x00000004)) { 176 // Used to have separate timers for "doit" and "all", but the timer 177 // overhead skewed the measurements. 178 jlong doit_time = _timer_rsc_phase1.milliseconds() + 179 _timer_rsc_phase2.milliseconds(); 180 jlong all_time = _timer_vm_op_prologue.milliseconds() + doit_time; 181 182 RC_TRACE(0x00000004, ("vm_op: all=" UINT64_FORMAT 183 " prologue=" UINT64_FORMAT " doit=" UINT64_FORMAT, all_time, 184 _timer_vm_op_prologue.milliseconds(), doit_time)); 185 RC_TRACE(0x00000004, 186 ("redefine_single_class: phase1=" UINT64_FORMAT " phase2=" UINT64_FORMAT, 187 _timer_rsc_phase1.milliseconds(), _timer_rsc_phase2.milliseconds())); 188 } 189 } 190 191 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) { 192 // classes for primitives cannot be redefined 193 if (java_lang_Class::is_primitive(klass_mirror)) { 194 return false; 195 } 196 Klass* the_class_oop = java_lang_Class::as_Klass(klass_mirror); 197 // classes for arrays cannot be redefined 198 if (the_class_oop == NULL || !the_class_oop->oop_is_instance()) { 199 return false; 200 } 201 return true; 202 } 203 204 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p 205 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For 206 // direct CP entries, there is just the current entry to append. For 207 // indirect and double-indirect CP entries, there are zero or more 208 // referenced CP entries along with the current entry to append. 209 // Indirect and double-indirect CP entries are handled by recursive 210 // calls to append_entry() as needed. The referenced CP entries are 211 // always appended to *merge_cp_p before the referee CP entry. These 212 // referenced CP entries may already exist in *merge_cp_p in which case 213 // there is nothing extra to append and only the current entry is 214 // appended. 215 void VM_RedefineClasses::append_entry(constantPoolHandle scratch_cp, 216 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, 217 TRAPS) { 218 219 // append is different depending on entry tag type 220 switch (scratch_cp->tag_at(scratch_i).value()) { 221 222 // The old verifier is implemented outside the VM. It loads classes, 223 // but does not resolve constant pool entries directly so we never 224 // see Class entries here with the old verifier. Similarly the old 225 // verifier does not like Class entries in the input constant pool. 226 // The split-verifier is implemented in the VM so it can optionally 227 // and directly resolve constant pool entries to load classes. The 228 // split-verifier can accept either Class entries or UnresolvedClass 229 // entries in the input constant pool. We revert the appended copy 230 // back to UnresolvedClass so that either verifier will be happy 231 // with the constant pool entry. 232 case JVM_CONSTANT_Class: 233 { 234 // revert the copy to JVM_CONSTANT_UnresolvedClass 235 (*merge_cp_p)->unresolved_klass_at_put(*merge_cp_length_p, 236 scratch_cp->klass_name_at(scratch_i)); 237 238 if (scratch_i != *merge_cp_length_p) { 239 // The new entry in *merge_cp_p is at a different index than 240 // the new entry in scratch_cp so we need to map the index values. 241 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 242 } 243 (*merge_cp_length_p)++; 244 } break; 245 246 // these are direct CP entries so they can be directly appended, 247 // but double and long take two constant pool entries 248 case JVM_CONSTANT_Double: // fall through 249 case JVM_CONSTANT_Long: 250 { 251 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p, 252 THREAD); 253 254 if (scratch_i != *merge_cp_length_p) { 255 // The new entry in *merge_cp_p is at a different index than 256 // the new entry in scratch_cp so we need to map the index values. 257 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 258 } 259 (*merge_cp_length_p) += 2; 260 } break; 261 262 // these are direct CP entries so they can be directly appended 263 case JVM_CONSTANT_Float: // fall through 264 case JVM_CONSTANT_Integer: // fall through 265 case JVM_CONSTANT_Utf8: // fall through 266 267 // This was an indirect CP entry, but it has been changed into 268 // Symbol*s so this entry can be directly appended. 269 case JVM_CONSTANT_String: // fall through 270 271 // These were indirect CP entries, but they have been changed into 272 // Symbol*s so these entries can be directly appended. 273 case JVM_CONSTANT_UnresolvedClass: // fall through 274 { 275 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p, 276 THREAD); 277 278 if (scratch_i != *merge_cp_length_p) { 279 // The new entry in *merge_cp_p is at a different index than 280 // the new entry in scratch_cp so we need to map the index values. 281 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 282 } 283 (*merge_cp_length_p)++; 284 } break; 285 286 // this is an indirect CP entry so it needs special handling 287 case JVM_CONSTANT_NameAndType: 288 { 289 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i); 290 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p, 291 merge_cp_length_p, THREAD); 292 293 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i); 294 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i, 295 merge_cp_p, merge_cp_length_p, 296 THREAD); 297 298 // If the referenced entries already exist in *merge_cp_p, then 299 // both new_name_ref_i and new_signature_ref_i will both be 0. 300 // In that case, all we are appending is the current entry. 301 if (new_name_ref_i != name_ref_i) { 302 RC_TRACE(0x00080000, 303 ("NameAndType entry@%d name_ref_index change: %d to %d", 304 *merge_cp_length_p, name_ref_i, new_name_ref_i)); 305 } 306 if (new_signature_ref_i != signature_ref_i) { 307 RC_TRACE(0x00080000, 308 ("NameAndType entry@%d signature_ref_index change: %d to %d", 309 *merge_cp_length_p, signature_ref_i, new_signature_ref_i)); 310 } 311 312 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p, 313 new_name_ref_i, new_signature_ref_i); 314 if (scratch_i != *merge_cp_length_p) { 315 // The new entry in *merge_cp_p is at a different index than 316 // the new entry in scratch_cp so we need to map the index values. 317 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 318 } 319 (*merge_cp_length_p)++; 320 } break; 321 322 // this is a double-indirect CP entry so it needs special handling 323 case JVM_CONSTANT_Fieldref: // fall through 324 case JVM_CONSTANT_InterfaceMethodref: // fall through 325 case JVM_CONSTANT_Methodref: 326 { 327 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i); 328 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i, 329 merge_cp_p, merge_cp_length_p, THREAD); 330 331 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i); 332 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i, 333 merge_cp_p, merge_cp_length_p, THREAD); 334 335 const char *entry_name; 336 switch (scratch_cp->tag_at(scratch_i).value()) { 337 case JVM_CONSTANT_Fieldref: 338 entry_name = "Fieldref"; 339 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i, 340 new_name_and_type_ref_i); 341 break; 342 case JVM_CONSTANT_InterfaceMethodref: 343 entry_name = "IFMethodref"; 344 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p, 345 new_klass_ref_i, new_name_and_type_ref_i); 346 break; 347 case JVM_CONSTANT_Methodref: 348 entry_name = "Methodref"; 349 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i, 350 new_name_and_type_ref_i); 351 break; 352 default: 353 guarantee(false, "bad switch"); 354 break; 355 } 356 357 if (klass_ref_i != new_klass_ref_i) { 358 RC_TRACE(0x00080000, ("%s entry@%d class_index changed: %d to %d", 359 entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i)); 360 } 361 if (name_and_type_ref_i != new_name_and_type_ref_i) { 362 RC_TRACE(0x00080000, 363 ("%s entry@%d name_and_type_index changed: %d to %d", 364 entry_name, *merge_cp_length_p, name_and_type_ref_i, 365 new_name_and_type_ref_i)); 366 } 367 368 if (scratch_i != *merge_cp_length_p) { 369 // The new entry in *merge_cp_p is at a different index than 370 // the new entry in scratch_cp so we need to map the index values. 371 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 372 } 373 (*merge_cp_length_p)++; 374 } break; 375 376 // this is an indirect CP entry so it needs special handling 377 case JVM_CONSTANT_MethodType: 378 { 379 int ref_i = scratch_cp->method_type_index_at(scratch_i); 380 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p, 381 merge_cp_length_p, THREAD); 382 if (new_ref_i != ref_i) { 383 RC_TRACE(0x00080000, 384 ("MethodType entry@%d ref_index change: %d to %d", 385 *merge_cp_length_p, ref_i, new_ref_i)); 386 } 387 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i); 388 if (scratch_i != *merge_cp_length_p) { 389 // The new entry in *merge_cp_p is at a different index than 390 // the new entry in scratch_cp so we need to map the index values. 391 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 392 } 393 (*merge_cp_length_p)++; 394 } break; 395 396 // this is an indirect CP entry so it needs special handling 397 case JVM_CONSTANT_MethodHandle: 398 { 399 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i); 400 int ref_i = scratch_cp->method_handle_index_at(scratch_i); 401 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p, 402 merge_cp_length_p, THREAD); 403 if (new_ref_i != ref_i) { 404 RC_TRACE(0x00080000, 405 ("MethodHandle entry@%d ref_index change: %d to %d", 406 *merge_cp_length_p, ref_i, new_ref_i)); 407 } 408 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i); 409 if (scratch_i != *merge_cp_length_p) { 410 // The new entry in *merge_cp_p is at a different index than 411 // the new entry in scratch_cp so we need to map the index values. 412 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 413 } 414 (*merge_cp_length_p)++; 415 } break; 416 417 // this is an indirect CP entry so it needs special handling 418 case JVM_CONSTANT_InvokeDynamic: 419 { 420 // Index of the bootstrap specifier in the operands array 421 int old_bs_i = scratch_cp->invoke_dynamic_bootstrap_specifier_index(scratch_i); 422 int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p, 423 merge_cp_length_p, THREAD); 424 // The bootstrap method NameAndType_info index 425 int old_ref_i = scratch_cp->invoke_dynamic_name_and_type_ref_index_at(scratch_i); 426 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p, 427 merge_cp_length_p, THREAD); 428 if (new_bs_i != old_bs_i) { 429 RC_TRACE(0x00080000, 430 ("InvokeDynamic entry@%d bootstrap_method_attr_index change: %d to %d", 431 *merge_cp_length_p, old_bs_i, new_bs_i)); 432 } 433 if (new_ref_i != old_ref_i) { 434 RC_TRACE(0x00080000, 435 ("InvokeDynamic entry@%d name_and_type_index change: %d to %d", 436 *merge_cp_length_p, old_ref_i, new_ref_i)); 437 } 438 439 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i); 440 if (scratch_i != *merge_cp_length_p) { 441 // The new entry in *merge_cp_p is at a different index than 442 // the new entry in scratch_cp so we need to map the index values. 443 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 444 } 445 (*merge_cp_length_p)++; 446 } break; 447 448 // At this stage, Class or UnresolvedClass could be here, but not 449 // ClassIndex 450 case JVM_CONSTANT_ClassIndex: // fall through 451 452 // Invalid is used as the tag for the second constant pool entry 453 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should 454 // not be seen by itself. 455 case JVM_CONSTANT_Invalid: // fall through 456 457 // At this stage, String could be here, but not StringIndex 458 case JVM_CONSTANT_StringIndex: // fall through 459 460 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be 461 // here 462 case JVM_CONSTANT_UnresolvedClassInError: // fall through 463 464 default: 465 { 466 // leave a breadcrumb 467 jbyte bad_value = scratch_cp->tag_at(scratch_i).value(); 468 ShouldNotReachHere(); 469 } break; 470 } // end switch tag value 471 } // end append_entry() 472 473 474 int VM_RedefineClasses::find_or_append_indirect_entry(constantPoolHandle scratch_cp, 475 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) { 476 477 int new_ref_i = ref_i; 478 bool match = (ref_i < *merge_cp_length_p) && 479 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i, THREAD); 480 481 if (!match) { 482 // forward reference in *merge_cp_p or not a direct match 483 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p, THREAD); 484 if (found_i != 0) { 485 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree"); 486 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry. 487 new_ref_i = found_i; 488 map_index(scratch_cp, ref_i, found_i); 489 } else { 490 // no match found so we have to append this entry to *merge_cp_p 491 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p, THREAD); 492 // The above call to append_entry() can only append one entry 493 // so the post call query of *merge_cp_length_p is only for 494 // the sake of consistency. 495 new_ref_i = *merge_cp_length_p - 1; 496 } 497 } 498 499 return new_ref_i; 500 } // end find_or_append_indirect_entry() 501 502 503 // Append a bootstrap specifier into the merge_cp operands that is semantically equal 504 // to the scratch_cp operands bootstrap specifier passed by the old_bs_i index. 505 // Recursively append new merge_cp entries referenced by the new bootstrap specifier. 506 void VM_RedefineClasses::append_operand(constantPoolHandle scratch_cp, int old_bs_i, 507 constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) { 508 509 int old_ref_i = scratch_cp->operand_bootstrap_method_ref_index_at(old_bs_i); 510 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p, 511 merge_cp_length_p, THREAD); 512 if (new_ref_i != old_ref_i) { 513 RC_TRACE(0x00080000, 514 ("operands entry@%d bootstrap method ref_index change: %d to %d", 515 _operands_cur_length, old_ref_i, new_ref_i)); 516 } 517 518 Array<u2>* merge_ops = (*merge_cp_p)->operands(); 519 int new_bs_i = _operands_cur_length; 520 // We have _operands_cur_length == 0 when the merge_cp operands is empty yet. 521 // However, the operand_offset_at(0) was set in the extend_operands() call. 522 int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0) 523 : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1); 524 int argc = scratch_cp->operand_argument_count_at(old_bs_i); 525 526 ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base); 527 merge_ops->at_put(new_base++, new_ref_i); 528 merge_ops->at_put(new_base++, argc); 529 530 for (int i = 0; i < argc; i++) { 531 int old_arg_ref_i = scratch_cp->operand_argument_index_at(old_bs_i, i); 532 int new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p, 533 merge_cp_length_p, THREAD); 534 merge_ops->at_put(new_base++, new_arg_ref_i); 535 if (new_arg_ref_i != old_arg_ref_i) { 536 RC_TRACE(0x00080000, 537 ("operands entry@%d bootstrap method argument ref_index change: %d to %d", 538 _operands_cur_length, old_arg_ref_i, new_arg_ref_i)); 539 } 540 } 541 if (old_bs_i != _operands_cur_length) { 542 // The bootstrap specifier in *merge_cp_p is at a different index than 543 // that in scratch_cp so we need to map the index values. 544 map_operand_index(old_bs_i, new_bs_i); 545 } 546 _operands_cur_length++; 547 } // end append_operand() 548 549 550 int VM_RedefineClasses::find_or_append_operand(constantPoolHandle scratch_cp, 551 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) { 552 553 int new_bs_i = old_bs_i; // bootstrap specifier index 554 bool match = (old_bs_i < _operands_cur_length) && 555 scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i, THREAD); 556 557 if (!match) { 558 // forward reference in *merge_cp_p or not a direct match 559 int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p, 560 _operands_cur_length, THREAD); 561 if (found_i != -1) { 562 guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree"); 563 // found a matching operand somewhere else in *merge_cp_p so just need a mapping 564 new_bs_i = found_i; 565 map_operand_index(old_bs_i, found_i); 566 } else { 567 // no match found so we have to append this bootstrap specifier to *merge_cp_p 568 append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p, THREAD); 569 new_bs_i = _operands_cur_length - 1; 570 } 571 } 572 return new_bs_i; 573 } // end find_or_append_operand() 574 575 576 void VM_RedefineClasses::finalize_operands_merge(constantPoolHandle merge_cp, TRAPS) { 577 if (merge_cp->operands() == NULL) { 578 return; 579 } 580 // Shrink the merge_cp operands 581 merge_cp->shrink_operands(_operands_cur_length, CHECK); 582 583 if (RC_TRACE_ENABLED(0x00040000)) { 584 // don't want to loop unless we are tracing 585 int count = 0; 586 for (int i = 1; i < _operands_index_map_p->length(); i++) { 587 int value = _operands_index_map_p->at(i); 588 if (value != -1) { 589 RC_TRACE_WITH_THREAD(0x00040000, THREAD, 590 ("operands_index_map[%d]: old=%d new=%d", count, i, value)); 591 count++; 592 } 593 } 594 } 595 // Clean-up 596 _operands_index_map_p = NULL; 597 _operands_cur_length = 0; 598 _operands_index_map_count = 0; 599 } // end finalize_operands_merge() 600 601 602 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions( 603 instanceKlassHandle the_class, 604 instanceKlassHandle scratch_class) { 605 int i; 606 607 // Check superclasses, or rather their names, since superclasses themselves can be 608 // requested to replace. 609 // Check for NULL superclass first since this might be java.lang.Object 610 if (the_class->super() != scratch_class->super() && 611 (the_class->super() == NULL || scratch_class->super() == NULL || 612 the_class->super()->name() != 613 scratch_class->super()->name())) { 614 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 615 } 616 617 // Check if the number, names and order of directly implemented interfaces are the same. 618 // I think in principle we should just check if the sets of names of directly implemented 619 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the 620 // .java file, also changes in .class file) should not matter. However, comparing sets is 621 // technically a bit more difficult, and, more importantly, I am not sure at present that the 622 // order of interfaces does not matter on the implementation level, i.e. that the VM does not 623 // rely on it somewhere. 624 Array<Klass*>* k_interfaces = the_class->local_interfaces(); 625 Array<Klass*>* k_new_interfaces = scratch_class->local_interfaces(); 626 int n_intfs = k_interfaces->length(); 627 if (n_intfs != k_new_interfaces->length()) { 628 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 629 } 630 for (i = 0; i < n_intfs; i++) { 631 if (k_interfaces->at(i)->name() != 632 k_new_interfaces->at(i)->name()) { 633 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 634 } 635 } 636 637 // Check whether class is in the error init state. 638 if (the_class->is_in_error_state()) { 639 // TBD #5057930: special error code is needed in 1.6 640 return JVMTI_ERROR_INVALID_CLASS; 641 } 642 643 // Check whether class modifiers are the same. 644 jushort old_flags = (jushort) the_class->access_flags().get_flags(); 645 jushort new_flags = (jushort) scratch_class->access_flags().get_flags(); 646 if (old_flags != new_flags) { 647 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED; 648 } 649 650 // Check if the number, names, types and order of fields declared in these classes 651 // are the same. 652 JavaFieldStream old_fs(the_class); 653 JavaFieldStream new_fs(scratch_class); 654 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) { 655 // access 656 old_flags = old_fs.access_flags().as_short(); 657 new_flags = new_fs.access_flags().as_short(); 658 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) { 659 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 660 } 661 // offset 662 if (old_fs.offset() != new_fs.offset()) { 663 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 664 } 665 // name and signature 666 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index()); 667 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index()); 668 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index()); 669 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index()); 670 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) { 671 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 672 } 673 } 674 675 // If both streams aren't done then we have a differing number of 676 // fields. 677 if (!old_fs.done() || !new_fs.done()) { 678 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 679 } 680 681 // Do a parallel walk through the old and new methods. Detect 682 // cases where they match (exist in both), have been added in 683 // the new methods, or have been deleted (exist only in the 684 // old methods). The class file parser places methods in order 685 // by method name, but does not order overloaded methods by 686 // signature. In order to determine what fate befell the methods, 687 // this code places the overloaded new methods that have matching 688 // old methods in the same order as the old methods and places 689 // new overloaded methods at the end of overloaded methods of 690 // that name. The code for this order normalization is adapted 691 // from the algorithm used in InstanceKlass::find_method(). 692 // Since we are swapping out of order entries as we find them, 693 // we only have to search forward through the overloaded methods. 694 // Methods which are added and have the same name as an existing 695 // method (but different signature) will be put at the end of 696 // the methods with that name, and the name mismatch code will 697 // handle them. 698 Array<Method*>* k_old_methods(the_class->methods()); 699 Array<Method*>* k_new_methods(scratch_class->methods()); 700 int n_old_methods = k_old_methods->length(); 701 int n_new_methods = k_new_methods->length(); 702 Thread* thread = Thread::current(); 703 704 int ni = 0; 705 int oi = 0; 706 while (true) { 707 Method* k_old_method; 708 Method* k_new_method; 709 enum { matched, added, deleted, undetermined } method_was = undetermined; 710 711 if (oi >= n_old_methods) { 712 if (ni >= n_new_methods) { 713 break; // we've looked at everything, done 714 } 715 // New method at the end 716 k_new_method = k_new_methods->at(ni); 717 method_was = added; 718 } else if (ni >= n_new_methods) { 719 // Old method, at the end, is deleted 720 k_old_method = k_old_methods->at(oi); 721 method_was = deleted; 722 } else { 723 // There are more methods in both the old and new lists 724 k_old_method = k_old_methods->at(oi); 725 k_new_method = k_new_methods->at(ni); 726 if (k_old_method->name() != k_new_method->name()) { 727 // Methods are sorted by method name, so a mismatch means added 728 // or deleted 729 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) { 730 method_was = added; 731 } else { 732 method_was = deleted; 733 } 734 } else if (k_old_method->signature() == k_new_method->signature()) { 735 // Both the name and signature match 736 method_was = matched; 737 } else { 738 // The name matches, but the signature doesn't, which means we have to 739 // search forward through the new overloaded methods. 740 int nj; // outside the loop for post-loop check 741 for (nj = ni + 1; nj < n_new_methods; nj++) { 742 Method* m = k_new_methods->at(nj); 743 if (k_old_method->name() != m->name()) { 744 // reached another method name so no more overloaded methods 745 method_was = deleted; 746 break; 747 } 748 if (k_old_method->signature() == m->signature()) { 749 // found a match so swap the methods 750 k_new_methods->at_put(ni, m); 751 k_new_methods->at_put(nj, k_new_method); 752 k_new_method = m; 753 method_was = matched; 754 break; 755 } 756 } 757 758 if (nj >= n_new_methods) { 759 // reached the end without a match; so method was deleted 760 method_was = deleted; 761 } 762 } 763 } 764 765 switch (method_was) { 766 case matched: 767 // methods match, be sure modifiers do too 768 old_flags = (jushort) k_old_method->access_flags().get_flags(); 769 new_flags = (jushort) k_new_method->access_flags().get_flags(); 770 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) { 771 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED; 772 } 773 { 774 u2 new_num = k_new_method->method_idnum(); 775 u2 old_num = k_old_method->method_idnum(); 776 if (new_num != old_num) { 777 Method* idnum_owner = scratch_class->method_with_idnum(old_num); 778 if (idnum_owner != NULL) { 779 // There is already a method assigned this idnum -- switch them 780 // Take current and original idnum from the new_method 781 idnum_owner->set_method_idnum(new_num); 782 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum()); 783 } 784 // Take current and original idnum from the old_method 785 k_new_method->set_method_idnum(old_num); 786 k_new_method->set_orig_method_idnum(k_old_method->orig_method_idnum()); 787 if (thread->has_pending_exception()) { 788 return JVMTI_ERROR_OUT_OF_MEMORY; 789 } 790 } 791 } 792 RC_TRACE(0x00008000, ("Method matched: new: %s [%d] == old: %s [%d]", 793 k_new_method->name_and_sig_as_C_string(), ni, 794 k_old_method->name_and_sig_as_C_string(), oi)); 795 // advance to next pair of methods 796 ++oi; 797 ++ni; 798 break; 799 case added: 800 // method added, see if it is OK 801 new_flags = (jushort) k_new_method->access_flags().get_flags(); 802 if ((new_flags & JVM_ACC_PRIVATE) == 0 803 // hack: private should be treated as final, but alas 804 || (new_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0 805 ) { 806 // new methods must be private 807 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED; 808 } 809 { 810 u2 num = the_class->next_method_idnum(); 811 if (num == ConstMethod::UNSET_IDNUM) { 812 // cannot add any more methods 813 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED; 814 } 815 u2 new_num = k_new_method->method_idnum(); 816 Method* idnum_owner = scratch_class->method_with_idnum(num); 817 if (idnum_owner != NULL) { 818 // There is already a method assigned this idnum -- switch them 819 // Take current and original idnum from the new_method 820 idnum_owner->set_method_idnum(new_num); 821 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum()); 822 } 823 k_new_method->set_method_idnum(num); 824 k_new_method->set_orig_method_idnum(num); 825 if (thread->has_pending_exception()) { 826 return JVMTI_ERROR_OUT_OF_MEMORY; 827 } 828 } 829 RC_TRACE(0x00008000, ("Method added: new: %s [%d]", 830 k_new_method->name_and_sig_as_C_string(), ni)); 831 ++ni; // advance to next new method 832 break; 833 case deleted: 834 // method deleted, see if it is OK 835 old_flags = (jushort) k_old_method->access_flags().get_flags(); 836 if ((old_flags & JVM_ACC_PRIVATE) == 0 837 // hack: private should be treated as final, but alas 838 || (old_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0 839 ) { 840 // deleted methods must be private 841 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED; 842 } 843 RC_TRACE(0x00008000, ("Method deleted: old: %s [%d]", 844 k_old_method->name_and_sig_as_C_string(), oi)); 845 ++oi; // advance to next old method 846 break; 847 default: 848 ShouldNotReachHere(); 849 } 850 } 851 852 return JVMTI_ERROR_NONE; 853 } 854 855 856 // Find new constant pool index value for old constant pool index value 857 // by seaching the index map. Returns zero (0) if there is no mapped 858 // value for the old constant pool index. 859 int VM_RedefineClasses::find_new_index(int old_index) { 860 if (_index_map_count == 0) { 861 // map is empty so nothing can be found 862 return 0; 863 } 864 865 if (old_index < 1 || old_index >= _index_map_p->length()) { 866 // The old_index is out of range so it is not mapped. This should 867 // not happen in regular constant pool merging use, but it can 868 // happen if a corrupt annotation is processed. 869 return 0; 870 } 871 872 int value = _index_map_p->at(old_index); 873 if (value == -1) { 874 // the old_index is not mapped 875 return 0; 876 } 877 878 return value; 879 } // end find_new_index() 880 881 882 // Find new bootstrap specifier index value for old bootstrap specifier index 883 // value by seaching the index map. Returns unused index (-1) if there is 884 // no mapped value for the old bootstrap specifier index. 885 int VM_RedefineClasses::find_new_operand_index(int old_index) { 886 if (_operands_index_map_count == 0) { 887 // map is empty so nothing can be found 888 return -1; 889 } 890 891 if (old_index == -1 || old_index >= _operands_index_map_p->length()) { 892 // The old_index is out of range so it is not mapped. 893 // This should not happen in regular constant pool merging use. 894 return -1; 895 } 896 897 int value = _operands_index_map_p->at(old_index); 898 if (value == -1) { 899 // the old_index is not mapped 900 return -1; 901 } 902 903 return value; 904 } // end find_new_operand_index() 905 906 907 // Returns true if the current mismatch is due to a resolved/unresolved 908 // class pair. Otherwise, returns false. 909 bool VM_RedefineClasses::is_unresolved_class_mismatch(constantPoolHandle cp1, 910 int index1, constantPoolHandle cp2, int index2) { 911 912 jbyte t1 = cp1->tag_at(index1).value(); 913 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) { 914 return false; // wrong entry type; not our special case 915 } 916 917 jbyte t2 = cp2->tag_at(index2).value(); 918 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) { 919 return false; // wrong entry type; not our special case 920 } 921 922 if (t1 == t2) { 923 return false; // not a mismatch; not our special case 924 } 925 926 char *s1 = cp1->klass_name_at(index1)->as_C_string(); 927 char *s2 = cp2->klass_name_at(index2)->as_C_string(); 928 if (strcmp(s1, s2) != 0) { 929 return false; // strings don't match; not our special case 930 } 931 932 return true; // made it through the gauntlet; this is our special case 933 } // end is_unresolved_class_mismatch() 934 935 936 jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) { 937 938 // For consistency allocate memory using os::malloc wrapper. 939 _scratch_classes = (Klass**) 940 os::malloc(sizeof(Klass*) * _class_count, mtClass); 941 if (_scratch_classes == NULL) { 942 return JVMTI_ERROR_OUT_OF_MEMORY; 943 } 944 // Zero initialize the _scratch_classes array. 945 for (int i = 0; i < _class_count; i++) { 946 _scratch_classes[i] = NULL; 947 } 948 949 ResourceMark rm(THREAD); 950 951 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current()); 952 // state can only be NULL if the current thread is exiting which 953 // should not happen since we're trying to do a RedefineClasses 954 guarantee(state != NULL, "exiting thread calling load_new_class_versions"); 955 for (int i = 0; i < _class_count; i++) { 956 // Create HandleMark so that any handles created while loading new class 957 // versions are deleted. Constant pools are deallocated while merging 958 // constant pools 959 HandleMark hm(THREAD); 960 961 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass); 962 // classes for primitives cannot be redefined 963 if (!is_modifiable_class(mirror)) { 964 return JVMTI_ERROR_UNMODIFIABLE_CLASS; 965 } 966 Klass* the_class_oop = java_lang_Class::as_Klass(mirror); 967 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop); 968 Symbol* the_class_sym = the_class->name(); 969 970 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 971 RC_TRACE_WITH_THREAD(0x00000001, THREAD, 972 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)", 973 the_class->external_name(), _class_load_kind, 974 os::available_memory() >> 10)); 975 976 ClassFileStream st((u1*) _class_defs[i].class_bytes, 977 _class_defs[i].class_byte_count, (char *)"__VM_RedefineClasses__"); 978 979 // Parse the stream. 980 Handle the_class_loader(THREAD, the_class->class_loader()); 981 Handle protection_domain(THREAD, the_class->protection_domain()); 982 // Set redefined class handle in JvmtiThreadState class. 983 // This redefined class is sent to agent event handler for class file 984 // load hook event. 985 state->set_class_being_redefined(&the_class, _class_load_kind); 986 987 Klass* k = SystemDictionary::parse_stream(the_class_sym, 988 the_class_loader, 989 protection_domain, 990 &st, 991 THREAD); 992 // Clear class_being_redefined just to be sure. 993 state->clear_class_being_redefined(); 994 995 // TODO: if this is retransform, and nothing changed we can skip it 996 997 instanceKlassHandle scratch_class (THREAD, k); 998 999 // Need to clean up allocated InstanceKlass if there's an error so assign 1000 // the result here. Caller deallocates all the scratch classes in case of 1001 // an error. 1002 _scratch_classes[i] = k; 1003 1004 if (HAS_PENDING_EXCEPTION) { 1005 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1006 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1007 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("parse_stream exception: '%s'", 1008 ex_name->as_C_string())); 1009 CLEAR_PENDING_EXCEPTION; 1010 1011 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) { 1012 return JVMTI_ERROR_UNSUPPORTED_VERSION; 1013 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) { 1014 return JVMTI_ERROR_INVALID_CLASS_FORMAT; 1015 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) { 1016 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION; 1017 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) { 1018 // The message will be "XXX (wrong name: YYY)" 1019 return JVMTI_ERROR_NAMES_DONT_MATCH; 1020 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1021 return JVMTI_ERROR_OUT_OF_MEMORY; 1022 } else { // Just in case more exceptions can be thrown.. 1023 return JVMTI_ERROR_FAILS_VERIFICATION; 1024 } 1025 } 1026 1027 // Ensure class is linked before redefine 1028 if (!the_class->is_linked()) { 1029 the_class->link_class(THREAD); 1030 if (HAS_PENDING_EXCEPTION) { 1031 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1032 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1033 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("link_class exception: '%s'", 1034 ex_name->as_C_string())); 1035 CLEAR_PENDING_EXCEPTION; 1036 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1037 return JVMTI_ERROR_OUT_OF_MEMORY; 1038 } else { 1039 return JVMTI_ERROR_INTERNAL; 1040 } 1041 } 1042 } 1043 1044 // Do the validity checks in compare_and_normalize_class_versions() 1045 // before verifying the byte codes. By doing these checks first, we 1046 // limit the number of functions that require redirection from 1047 // the_class to scratch_class. In particular, we don't have to 1048 // modify JNI GetSuperclass() and thus won't change its performance. 1049 jvmtiError res = compare_and_normalize_class_versions(the_class, 1050 scratch_class); 1051 if (res != JVMTI_ERROR_NONE) { 1052 return res; 1053 } 1054 1055 // verify what the caller passed us 1056 { 1057 // The bug 6214132 caused the verification to fail. 1058 // Information about the_class and scratch_class is temporarily 1059 // recorded into jvmtiThreadState. This data is used to redirect 1060 // the_class to scratch_class in the JVM_* functions called by the 1061 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed 1062 // description. 1063 RedefineVerifyMark rvm(&the_class, &scratch_class, state); 1064 Verifier::verify( 1065 scratch_class, Verifier::ThrowException, true, THREAD); 1066 } 1067 1068 if (HAS_PENDING_EXCEPTION) { 1069 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1070 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1071 RC_TRACE_WITH_THREAD(0x00000002, THREAD, 1072 ("verify_byte_codes exception: '%s'", ex_name->as_C_string())); 1073 CLEAR_PENDING_EXCEPTION; 1074 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1075 return JVMTI_ERROR_OUT_OF_MEMORY; 1076 } else { 1077 // tell the caller the bytecodes are bad 1078 return JVMTI_ERROR_FAILS_VERIFICATION; 1079 } 1080 } 1081 1082 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD); 1083 if (HAS_PENDING_EXCEPTION) { 1084 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1085 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1086 RC_TRACE_WITH_THREAD(0x00000002, THREAD, 1087 ("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string())); 1088 CLEAR_PENDING_EXCEPTION; 1089 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1090 return JVMTI_ERROR_OUT_OF_MEMORY; 1091 } else { 1092 return JVMTI_ERROR_INTERNAL; 1093 } 1094 } 1095 1096 if (VerifyMergedCPBytecodes) { 1097 // verify what we have done during constant pool merging 1098 { 1099 RedefineVerifyMark rvm(&the_class, &scratch_class, state); 1100 Verifier::verify(scratch_class, Verifier::ThrowException, true, THREAD); 1101 } 1102 1103 if (HAS_PENDING_EXCEPTION) { 1104 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1105 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1106 RC_TRACE_WITH_THREAD(0x00000002, THREAD, 1107 ("verify_byte_codes post merge-CP exception: '%s'", 1108 ex_name->as_C_string())); 1109 CLEAR_PENDING_EXCEPTION; 1110 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1111 return JVMTI_ERROR_OUT_OF_MEMORY; 1112 } else { 1113 // tell the caller that constant pool merging screwed up 1114 return JVMTI_ERROR_INTERNAL; 1115 } 1116 } 1117 } 1118 1119 Rewriter::rewrite(scratch_class, THREAD); 1120 if (!HAS_PENDING_EXCEPTION) { 1121 scratch_class->link_methods(THREAD); 1122 } 1123 if (HAS_PENDING_EXCEPTION) { 1124 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1125 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1126 RC_TRACE_WITH_THREAD(0x00000002, THREAD, 1127 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string())); 1128 CLEAR_PENDING_EXCEPTION; 1129 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1130 return JVMTI_ERROR_OUT_OF_MEMORY; 1131 } else { 1132 return JVMTI_ERROR_INTERNAL; 1133 } 1134 } 1135 1136 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1137 RC_TRACE_WITH_THREAD(0x00000001, THREAD, 1138 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)", 1139 the_class->external_name(), os::available_memory() >> 10)); 1140 } 1141 1142 return JVMTI_ERROR_NONE; 1143 } 1144 1145 1146 // Map old_index to new_index as needed. scratch_cp is only needed 1147 // for RC_TRACE() calls. 1148 void VM_RedefineClasses::map_index(constantPoolHandle scratch_cp, 1149 int old_index, int new_index) { 1150 if (find_new_index(old_index) != 0) { 1151 // old_index is already mapped 1152 return; 1153 } 1154 1155 if (old_index == new_index) { 1156 // no mapping is needed 1157 return; 1158 } 1159 1160 _index_map_p->at_put(old_index, new_index); 1161 _index_map_count++; 1162 1163 RC_TRACE(0x00040000, ("mapped tag %d at index %d to %d", 1164 scratch_cp->tag_at(old_index).value(), old_index, new_index)); 1165 } // end map_index() 1166 1167 1168 // Map old_index to new_index as needed. 1169 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) { 1170 if (find_new_operand_index(old_index) != -1) { 1171 // old_index is already mapped 1172 return; 1173 } 1174 1175 if (old_index == new_index) { 1176 // no mapping is needed 1177 return; 1178 } 1179 1180 _operands_index_map_p->at_put(old_index, new_index); 1181 _operands_index_map_count++; 1182 1183 RC_TRACE(0x00040000, ("mapped bootstrap specifier at index %d to %d", old_index, new_index)); 1184 } // end map_index() 1185 1186 1187 // Merge old_cp and scratch_cp and return the results of the merge via 1188 // merge_cp_p. The number of entries in *merge_cp_p is returned via 1189 // merge_cp_length_p. The entries in old_cp occupy the same locations 1190 // in *merge_cp_p. Also creates a map of indices from entries in 1191 // scratch_cp to the corresponding entry in *merge_cp_p. Index map 1192 // entries are only created for entries in scratch_cp that occupy a 1193 // different location in *merged_cp_p. 1194 bool VM_RedefineClasses::merge_constant_pools(constantPoolHandle old_cp, 1195 constantPoolHandle scratch_cp, constantPoolHandle *merge_cp_p, 1196 int *merge_cp_length_p, TRAPS) { 1197 1198 if (merge_cp_p == NULL) { 1199 assert(false, "caller must provide scratch constantPool"); 1200 return false; // robustness 1201 } 1202 if (merge_cp_length_p == NULL) { 1203 assert(false, "caller must provide scratch CP length"); 1204 return false; // robustness 1205 } 1206 // Worst case we need old_cp->length() + scratch_cp()->length(), 1207 // but the caller might be smart so make sure we have at least 1208 // the minimum. 1209 if ((*merge_cp_p)->length() < old_cp->length()) { 1210 assert(false, "merge area too small"); 1211 return false; // robustness 1212 } 1213 1214 RC_TRACE_WITH_THREAD(0x00010000, THREAD, 1215 ("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(), 1216 scratch_cp->length())); 1217 1218 { 1219 // Pass 0: 1220 // The old_cp is copied to *merge_cp_p; this means that any code 1221 // using old_cp does not have to change. This work looks like a 1222 // perfect fit for ConstantPool*::copy_cp_to(), but we need to 1223 // handle one special case: 1224 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass 1225 // This will make verification happy. 1226 1227 int old_i; // index into old_cp 1228 1229 // index zero (0) is not used in constantPools 1230 for (old_i = 1; old_i < old_cp->length(); old_i++) { 1231 // leave debugging crumb 1232 jbyte old_tag = old_cp->tag_at(old_i).value(); 1233 switch (old_tag) { 1234 case JVM_CONSTANT_Class: 1235 case JVM_CONSTANT_UnresolvedClass: 1236 // revert the copy to JVM_CONSTANT_UnresolvedClass 1237 // May be resolving while calling this so do the same for 1238 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition) 1239 (*merge_cp_p)->unresolved_klass_at_put(old_i, 1240 old_cp->klass_name_at(old_i)); 1241 break; 1242 1243 case JVM_CONSTANT_Double: 1244 case JVM_CONSTANT_Long: 1245 // just copy the entry to *merge_cp_p, but double and long take 1246 // two constant pool entries 1247 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0); 1248 old_i++; 1249 break; 1250 1251 default: 1252 // just copy the entry to *merge_cp_p 1253 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0); 1254 break; 1255 } 1256 } // end for each old_cp entry 1257 1258 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_0); 1259 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_0); 1260 1261 // We don't need to sanity check that *merge_cp_length_p is within 1262 // *merge_cp_p bounds since we have the minimum on-entry check above. 1263 (*merge_cp_length_p) = old_i; 1264 } 1265 1266 // merge_cp_len should be the same as old_cp->length() at this point 1267 // so this trace message is really a "warm-and-breathing" message. 1268 RC_TRACE_WITH_THREAD(0x00020000, THREAD, 1269 ("after pass 0: merge_cp_len=%d", *merge_cp_length_p)); 1270 1271 int scratch_i; // index into scratch_cp 1272 { 1273 // Pass 1a: 1274 // Compare scratch_cp entries to the old_cp entries that we have 1275 // already copied to *merge_cp_p. In this pass, we are eliminating 1276 // exact duplicates (matching entry at same index) so we only 1277 // compare entries in the common indice range. 1278 int increment = 1; 1279 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length()); 1280 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) { 1281 switch (scratch_cp->tag_at(scratch_i).value()) { 1282 case JVM_CONSTANT_Double: 1283 case JVM_CONSTANT_Long: 1284 // double and long take two constant pool entries 1285 increment = 2; 1286 break; 1287 1288 default: 1289 increment = 1; 1290 break; 1291 } 1292 1293 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p, 1294 scratch_i, CHECK_0); 1295 if (match) { 1296 // found a match at the same index so nothing more to do 1297 continue; 1298 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i, 1299 *merge_cp_p, scratch_i)) { 1300 // The mismatch in compare_entry_to() above is because of a 1301 // resolved versus unresolved class entry at the same index 1302 // with the same string value. Since Pass 0 reverted any 1303 // class entries to unresolved class entries in *merge_cp_p, 1304 // we go with the unresolved class entry. 1305 continue; 1306 } 1307 1308 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, 1309 CHECK_0); 1310 if (found_i != 0) { 1311 guarantee(found_i != scratch_i, 1312 "compare_entry_to() and find_matching_entry() do not agree"); 1313 1314 // Found a matching entry somewhere else in *merge_cp_p so 1315 // just need a mapping entry. 1316 map_index(scratch_cp, scratch_i, found_i); 1317 continue; 1318 } 1319 1320 // The find_matching_entry() call above could fail to find a match 1321 // due to a resolved versus unresolved class or string entry situation 1322 // like we solved above with the is_unresolved_*_mismatch() calls. 1323 // However, we would have to call is_unresolved_*_mismatch() over 1324 // all of *merge_cp_p (potentially) and that doesn't seem to be 1325 // worth the time. 1326 1327 // No match found so we have to append this entry and any unique 1328 // referenced entries to *merge_cp_p. 1329 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p, 1330 CHECK_0); 1331 } 1332 } 1333 1334 RC_TRACE_WITH_THREAD(0x00020000, THREAD, 1335 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", 1336 *merge_cp_length_p, scratch_i, _index_map_count)); 1337 1338 if (scratch_i < scratch_cp->length()) { 1339 // Pass 1b: 1340 // old_cp is smaller than scratch_cp so there are entries in 1341 // scratch_cp that we have not yet processed. We take care of 1342 // those now. 1343 int increment = 1; 1344 for (; scratch_i < scratch_cp->length(); scratch_i += increment) { 1345 switch (scratch_cp->tag_at(scratch_i).value()) { 1346 case JVM_CONSTANT_Double: 1347 case JVM_CONSTANT_Long: 1348 // double and long take two constant pool entries 1349 increment = 2; 1350 break; 1351 1352 default: 1353 increment = 1; 1354 break; 1355 } 1356 1357 int found_i = 1358 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0); 1359 if (found_i != 0) { 1360 // Found a matching entry somewhere else in *merge_cp_p so 1361 // just need a mapping entry. 1362 map_index(scratch_cp, scratch_i, found_i); 1363 continue; 1364 } 1365 1366 // No match found so we have to append this entry and any unique 1367 // referenced entries to *merge_cp_p. 1368 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p, 1369 CHECK_0); 1370 } 1371 1372 RC_TRACE_WITH_THREAD(0x00020000, THREAD, 1373 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", 1374 *merge_cp_length_p, scratch_i, _index_map_count)); 1375 } 1376 finalize_operands_merge(*merge_cp_p, THREAD); 1377 1378 return true; 1379 } // end merge_constant_pools() 1380 1381 1382 // Scoped object to clean up the constant pool(s) created for merging 1383 class MergeCPCleaner { 1384 ClassLoaderData* _loader_data; 1385 ConstantPool* _cp; 1386 ConstantPool* _scratch_cp; 1387 public: 1388 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) : 1389 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {} 1390 ~MergeCPCleaner() { 1391 _loader_data->add_to_deallocate_list(_cp); 1392 if (_scratch_cp != NULL) { 1393 _loader_data->add_to_deallocate_list(_scratch_cp); 1394 } 1395 } 1396 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; } 1397 }; 1398 1399 // Merge constant pools between the_class and scratch_class and 1400 // potentially rewrite bytecodes in scratch_class to use the merged 1401 // constant pool. 1402 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite( 1403 instanceKlassHandle the_class, instanceKlassHandle scratch_class, 1404 TRAPS) { 1405 // worst case merged constant pool length is old and new combined 1406 int merge_cp_length = the_class->constants()->length() 1407 + scratch_class->constants()->length(); 1408 1409 // Constant pools are not easily reused so we allocate a new one 1410 // each time. 1411 // merge_cp is created unsafe for concurrent GC processing. It 1412 // should be marked safe before discarding it. Even though 1413 // garbage, if it crosses a card boundary, it may be scanned 1414 // in order to find the start of the first complete object on the card. 1415 ClassLoaderData* loader_data = the_class->class_loader_data(); 1416 ConstantPool* merge_cp_oop = 1417 ConstantPool::allocate(loader_data, 1418 merge_cp_length, 1419 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1420 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop); 1421 1422 HandleMark hm(THREAD); // make sure handles are cleared before 1423 // MergeCPCleaner clears out merge_cp_oop 1424 constantPoolHandle merge_cp(THREAD, merge_cp_oop); 1425 1426 // Get constants() from the old class because it could have been rewritten 1427 // while we were at a safepoint allocating a new constant pool. 1428 constantPoolHandle old_cp(THREAD, the_class->constants()); 1429 constantPoolHandle scratch_cp(THREAD, scratch_class->constants()); 1430 1431 // If the length changed, the class was redefined out from under us. Return 1432 // an error. 1433 if (merge_cp_length != the_class->constants()->length() 1434 + scratch_class->constants()->length()) { 1435 return JVMTI_ERROR_INTERNAL; 1436 } 1437 1438 // Update the version number of the constant pool 1439 merge_cp->increment_and_save_version(old_cp->version()); 1440 1441 ResourceMark rm(THREAD); 1442 _index_map_count = 0; 1443 _index_map_p = new intArray(scratch_cp->length(), -1); 1444 1445 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands()); 1446 _operands_index_map_count = 0; 1447 _operands_index_map_p = new intArray( 1448 ConstantPool::operand_array_length(scratch_cp->operands()), -1); 1449 1450 // reference to the cp holder is needed for copy_operands() 1451 merge_cp->set_pool_holder(scratch_class()); 1452 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp, 1453 &merge_cp_length, THREAD); 1454 merge_cp->set_pool_holder(NULL); 1455 1456 if (!result) { 1457 // The merge can fail due to memory allocation failure or due 1458 // to robustness checks. 1459 return JVMTI_ERROR_INTERNAL; 1460 } 1461 1462 RC_TRACE_WITH_THREAD(0x00010000, THREAD, 1463 ("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count)); 1464 1465 if (_index_map_count == 0) { 1466 // there is nothing to map between the new and merged constant pools 1467 1468 if (old_cp->length() == scratch_cp->length()) { 1469 // The old and new constant pools are the same length and the 1470 // index map is empty. This means that the three constant pools 1471 // are equivalent (but not the same). Unfortunately, the new 1472 // constant pool has not gone through link resolution nor have 1473 // the new class bytecodes gone through constant pool cache 1474 // rewriting so we can't use the old constant pool with the new 1475 // class. 1476 1477 // toss the merged constant pool at return 1478 } else if (old_cp->length() < scratch_cp->length()) { 1479 // The old constant pool has fewer entries than the new constant 1480 // pool and the index map is empty. This means the new constant 1481 // pool is a superset of the old constant pool. However, the old 1482 // class bytecodes have already gone through constant pool cache 1483 // rewriting so we can't use the new constant pool with the old 1484 // class. 1485 1486 // toss the merged constant pool at return 1487 } else { 1488 // The old constant pool has more entries than the new constant 1489 // pool and the index map is empty. This means that both the old 1490 // and merged constant pools are supersets of the new constant 1491 // pool. 1492 1493 // Replace the new constant pool with a shrunken copy of the 1494 // merged constant pool 1495 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, 1496 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1497 // The new constant pool replaces scratch_cp so have cleaner clean it up. 1498 // It can't be cleaned up while there are handles to it. 1499 cp_cleaner.add_scratch_cp(scratch_cp()); 1500 } 1501 } else { 1502 if (RC_TRACE_ENABLED(0x00040000)) { 1503 // don't want to loop unless we are tracing 1504 int count = 0; 1505 for (int i = 1; i < _index_map_p->length(); i++) { 1506 int value = _index_map_p->at(i); 1507 1508 if (value != -1) { 1509 RC_TRACE_WITH_THREAD(0x00040000, THREAD, 1510 ("index_map[%d]: old=%d new=%d", count, i, value)); 1511 count++; 1512 } 1513 } 1514 } 1515 1516 // We have entries mapped between the new and merged constant pools 1517 // so we have to rewrite some constant pool references. 1518 if (!rewrite_cp_refs(scratch_class, THREAD)) { 1519 return JVMTI_ERROR_INTERNAL; 1520 } 1521 1522 // Replace the new constant pool with a shrunken copy of the 1523 // merged constant pool so now the rewritten bytecodes have 1524 // valid references; the previous new constant pool will get 1525 // GCed. 1526 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, 1527 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1528 // The new constant pool replaces scratch_cp so have cleaner clean it up. 1529 // It can't be cleaned up while there are handles to it. 1530 cp_cleaner.add_scratch_cp(scratch_cp()); 1531 } 1532 1533 return JVMTI_ERROR_NONE; 1534 } // end merge_cp_and_rewrite() 1535 1536 1537 // Rewrite constant pool references in klass scratch_class. 1538 bool VM_RedefineClasses::rewrite_cp_refs(instanceKlassHandle scratch_class, 1539 TRAPS) { 1540 1541 // rewrite constant pool references in the methods: 1542 if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) { 1543 // propagate failure back to caller 1544 return false; 1545 } 1546 1547 // rewrite constant pool references in the class_annotations: 1548 if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) { 1549 // propagate failure back to caller 1550 return false; 1551 } 1552 1553 // rewrite constant pool references in the fields_annotations: 1554 if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) { 1555 // propagate failure back to caller 1556 return false; 1557 } 1558 1559 // rewrite constant pool references in the methods_annotations: 1560 if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) { 1561 // propagate failure back to caller 1562 return false; 1563 } 1564 1565 // rewrite constant pool references in the methods_parameter_annotations: 1566 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class, 1567 THREAD)) { 1568 // propagate failure back to caller 1569 return false; 1570 } 1571 1572 // rewrite constant pool references in the methods_default_annotations: 1573 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class, 1574 THREAD)) { 1575 // propagate failure back to caller 1576 return false; 1577 } 1578 1579 // rewrite constant pool references in the class_type_annotations: 1580 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class, THREAD)) { 1581 // propagate failure back to caller 1582 return false; 1583 } 1584 1585 // rewrite constant pool references in the fields_type_annotations: 1586 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class, THREAD)) { 1587 // propagate failure back to caller 1588 return false; 1589 } 1590 1591 // rewrite constant pool references in the methods_type_annotations: 1592 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class, THREAD)) { 1593 // propagate failure back to caller 1594 return false; 1595 } 1596 1597 // There can be type annotations in the Code part of a method_info attribute. 1598 // These annotations are not accessible, even by reflection. 1599 // Currently they are not even parsed by the ClassFileParser. 1600 // If runtime access is added they will also need to be rewritten. 1601 1602 // rewrite source file name index: 1603 u2 source_file_name_idx = scratch_class->source_file_name_index(); 1604 if (source_file_name_idx != 0) { 1605 u2 new_source_file_name_idx = find_new_index(source_file_name_idx); 1606 if (new_source_file_name_idx != 0) { 1607 scratch_class->set_source_file_name_index(new_source_file_name_idx); 1608 } 1609 } 1610 1611 // rewrite class generic signature index: 1612 u2 generic_signature_index = scratch_class->generic_signature_index(); 1613 if (generic_signature_index != 0) { 1614 u2 new_generic_signature_index = find_new_index(generic_signature_index); 1615 if (new_generic_signature_index != 0) { 1616 scratch_class->set_generic_signature_index(new_generic_signature_index); 1617 } 1618 } 1619 1620 return true; 1621 } // end rewrite_cp_refs() 1622 1623 // Rewrite constant pool references in the methods. 1624 bool VM_RedefineClasses::rewrite_cp_refs_in_methods( 1625 instanceKlassHandle scratch_class, TRAPS) { 1626 1627 Array<Method*>* methods = scratch_class->methods(); 1628 1629 if (methods == NULL || methods->length() == 0) { 1630 // no methods so nothing to do 1631 return true; 1632 } 1633 1634 // rewrite constant pool references in the methods: 1635 for (int i = methods->length() - 1; i >= 0; i--) { 1636 methodHandle method(THREAD, methods->at(i)); 1637 methodHandle new_method; 1638 rewrite_cp_refs_in_method(method, &new_method, THREAD); 1639 if (!new_method.is_null()) { 1640 // the method has been replaced so save the new method version 1641 // even in the case of an exception. original method is on the 1642 // deallocation list. 1643 methods->at_put(i, new_method()); 1644 } 1645 if (HAS_PENDING_EXCEPTION) { 1646 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1647 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1648 RC_TRACE_WITH_THREAD(0x00000002, THREAD, 1649 ("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string())); 1650 // Need to clear pending exception here as the super caller sets 1651 // the JVMTI_ERROR_INTERNAL if the returned value is false. 1652 CLEAR_PENDING_EXCEPTION; 1653 return false; 1654 } 1655 } 1656 1657 return true; 1658 } 1659 1660 1661 // Rewrite constant pool references in the specific method. This code 1662 // was adapted from Rewriter::rewrite_method(). 1663 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method, 1664 methodHandle *new_method_p, TRAPS) { 1665 1666 *new_method_p = methodHandle(); // default is no new method 1667 1668 // We cache a pointer to the bytecodes here in code_base. If GC 1669 // moves the Method*, then the bytecodes will also move which 1670 // will likely cause a crash. We create a No_Safepoint_Verifier 1671 // object to detect whether we pass a possible safepoint in this 1672 // code block. 1673 No_Safepoint_Verifier nsv; 1674 1675 // Bytecodes and their length 1676 address code_base = method->code_base(); 1677 int code_length = method->code_size(); 1678 1679 int bc_length; 1680 for (int bci = 0; bci < code_length; bci += bc_length) { 1681 address bcp = code_base + bci; 1682 Bytecodes::Code c = (Bytecodes::Code)(*bcp); 1683 1684 bc_length = Bytecodes::length_for(c); 1685 if (bc_length == 0) { 1686 // More complicated bytecodes report a length of zero so 1687 // we have to try again a slightly different way. 1688 bc_length = Bytecodes::length_at(method(), bcp); 1689 } 1690 1691 assert(bc_length != 0, "impossible bytecode length"); 1692 1693 switch (c) { 1694 case Bytecodes::_ldc: 1695 { 1696 int cp_index = *(bcp + 1); 1697 int new_index = find_new_index(cp_index); 1698 1699 if (StressLdcRewrite && new_index == 0) { 1700 // If we are stressing ldc -> ldc_w rewriting, then we 1701 // always need a new_index value. 1702 new_index = cp_index; 1703 } 1704 if (new_index != 0) { 1705 // the original index is mapped so we have more work to do 1706 if (!StressLdcRewrite && new_index <= max_jubyte) { 1707 // The new value can still use ldc instead of ldc_w 1708 // unless we are trying to stress ldc -> ldc_w rewriting 1709 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 1710 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), 1711 bcp, cp_index, new_index)); 1712 *(bcp + 1) = new_index; 1713 } else { 1714 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 1715 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d", 1716 Bytecodes::name(c), bcp, cp_index, new_index)); 1717 // the new value needs ldc_w instead of ldc 1718 u_char inst_buffer[4]; // max instruction size is 4 bytes 1719 bcp = (address)inst_buffer; 1720 // construct new instruction sequence 1721 *bcp = Bytecodes::_ldc_w; 1722 bcp++; 1723 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w. 1724 // See comment below for difference between put_Java_u2() 1725 // and put_native_u2(). 1726 Bytes::put_Java_u2(bcp, new_index); 1727 1728 Relocator rc(method, NULL /* no RelocatorListener needed */); 1729 methodHandle m; 1730 { 1731 Pause_No_Safepoint_Verifier pnsv(&nsv); 1732 1733 // ldc is 2 bytes and ldc_w is 3 bytes 1734 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK); 1735 } 1736 1737 // return the new method so that the caller can update 1738 // the containing class 1739 *new_method_p = method = m; 1740 // switch our bytecode processing loop from the old method 1741 // to the new method 1742 code_base = method->code_base(); 1743 code_length = method->code_size(); 1744 bcp = code_base + bci; 1745 c = (Bytecodes::Code)(*bcp); 1746 bc_length = Bytecodes::length_for(c); 1747 assert(bc_length != 0, "sanity check"); 1748 } // end we need ldc_w instead of ldc 1749 } // end if there is a mapped index 1750 } break; 1751 1752 // these bytecodes have a two-byte constant pool index 1753 case Bytecodes::_anewarray : // fall through 1754 case Bytecodes::_checkcast : // fall through 1755 case Bytecodes::_getfield : // fall through 1756 case Bytecodes::_getstatic : // fall through 1757 case Bytecodes::_instanceof : // fall through 1758 case Bytecodes::_invokedynamic : // fall through 1759 case Bytecodes::_invokeinterface: // fall through 1760 case Bytecodes::_invokespecial : // fall through 1761 case Bytecodes::_invokestatic : // fall through 1762 case Bytecodes::_invokevirtual : // fall through 1763 case Bytecodes::_ldc_w : // fall through 1764 case Bytecodes::_ldc2_w : // fall through 1765 case Bytecodes::_multianewarray : // fall through 1766 case Bytecodes::_new : // fall through 1767 case Bytecodes::_putfield : // fall through 1768 case Bytecodes::_putstatic : 1769 { 1770 address p = bcp + 1; 1771 int cp_index = Bytes::get_Java_u2(p); 1772 int new_index = find_new_index(cp_index); 1773 if (new_index != 0) { 1774 // the original index is mapped so update w/ new value 1775 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 1776 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), 1777 bcp, cp_index, new_index)); 1778 // Rewriter::rewrite_method() uses put_native_u2() in this 1779 // situation because it is reusing the constant pool index 1780 // location for a native index into the ConstantPoolCache. 1781 // Since we are updating the constant pool index prior to 1782 // verification and ConstantPoolCache initialization, we 1783 // need to keep the new index in Java byte order. 1784 Bytes::put_Java_u2(p, new_index); 1785 } 1786 } break; 1787 } 1788 } // end for each bytecode 1789 1790 // We also need to rewrite the parameter name indexes, if there is 1791 // method parameter data present 1792 if(method->has_method_parameters()) { 1793 const int len = method->method_parameters_length(); 1794 MethodParametersElement* elem = method->method_parameters_start(); 1795 1796 for (int i = 0; i < len; i++) { 1797 const u2 cp_index = elem[i].name_cp_index; 1798 const u2 new_cp_index = find_new_index(cp_index); 1799 if (new_cp_index != 0) { 1800 elem[i].name_cp_index = new_cp_index; 1801 } 1802 } 1803 } 1804 } // end rewrite_cp_refs_in_method() 1805 1806 1807 // Rewrite constant pool references in the class_annotations field. 1808 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations( 1809 instanceKlassHandle scratch_class, TRAPS) { 1810 1811 AnnotationArray* class_annotations = scratch_class->class_annotations(); 1812 if (class_annotations == NULL || class_annotations->length() == 0) { 1813 // no class_annotations so nothing to do 1814 return true; 1815 } 1816 1817 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1818 ("class_annotations length=%d", class_annotations->length())); 1819 1820 int byte_i = 0; // byte index into class_annotations 1821 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i, 1822 THREAD); 1823 } 1824 1825 1826 // Rewrite constant pool references in an annotations typeArray. This 1827 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute 1828 // that is described in section 4.8.15 of the 2nd-edition of the VM spec: 1829 // 1830 // annotations_typeArray { 1831 // u2 num_annotations; 1832 // annotation annotations[num_annotations]; 1833 // } 1834 // 1835 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray( 1836 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) { 1837 1838 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 1839 // not enough room for num_annotations field 1840 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1841 ("length() is too small for num_annotations field")); 1842 return false; 1843 } 1844 1845 u2 num_annotations = 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 ("num_annotations=%d", num_annotations)); 1851 1852 int calc_num_annotations = 0; 1853 for (; calc_num_annotations < num_annotations; calc_num_annotations++) { 1854 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, 1855 byte_i_ref, THREAD)) { 1856 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1857 ("bad annotation_struct at %d", calc_num_annotations)); 1858 // propagate failure back to caller 1859 return false; 1860 } 1861 } 1862 assert(num_annotations == calc_num_annotations, "sanity check"); 1863 1864 return true; 1865 } // end rewrite_cp_refs_in_annotations_typeArray() 1866 1867 1868 // Rewrite constant pool references in the annotation struct portion of 1869 // an annotations_typeArray. This "structure" is from section 4.8.15 of 1870 // the 2nd-edition of the VM spec: 1871 // 1872 // struct annotation { 1873 // u2 type_index; 1874 // u2 num_element_value_pairs; 1875 // { 1876 // u2 element_name_index; 1877 // element_value value; 1878 // } element_value_pairs[num_element_value_pairs]; 1879 // } 1880 // 1881 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct( 1882 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) { 1883 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) { 1884 // not enough room for smallest annotation_struct 1885 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1886 ("length() is too small for annotation_struct")); 1887 return false; 1888 } 1889 1890 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray, 1891 byte_i_ref, "mapped old type_index=%d", THREAD); 1892 1893 u2 num_element_value_pairs = Bytes::get_Java_u2((address) 1894 annotations_typeArray->adr_at(byte_i_ref)); 1895 byte_i_ref += 2; 1896 1897 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1898 ("type_index=%d num_element_value_pairs=%d", type_index, 1899 num_element_value_pairs)); 1900 1901 int calc_num_element_value_pairs = 0; 1902 for (; calc_num_element_value_pairs < num_element_value_pairs; 1903 calc_num_element_value_pairs++) { 1904 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 1905 // not enough room for another element_name_index, let alone 1906 // the rest of another component 1907 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1908 ("length() is too small for element_name_index")); 1909 return false; 1910 } 1911 1912 u2 element_name_index = rewrite_cp_ref_in_annotation_data( 1913 annotations_typeArray, byte_i_ref, 1914 "mapped old element_name_index=%d", THREAD); 1915 1916 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1917 ("element_name_index=%d", element_name_index)); 1918 1919 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, 1920 byte_i_ref, THREAD)) { 1921 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1922 ("bad element_value at %d", calc_num_element_value_pairs)); 1923 // propagate failure back to caller 1924 return false; 1925 } 1926 } // end for each component 1927 assert(num_element_value_pairs == calc_num_element_value_pairs, 1928 "sanity check"); 1929 1930 return true; 1931 } // end rewrite_cp_refs_in_annotation_struct() 1932 1933 1934 // Rewrite a constant pool reference at the current position in 1935 // annotations_typeArray if needed. Returns the original constant 1936 // pool reference if a rewrite was not needed or the new constant 1937 // pool reference if a rewrite was needed. 1938 PRAGMA_DIAG_PUSH 1939 PRAGMA_FORMAT_NONLITERAL_IGNORED 1940 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data( 1941 AnnotationArray* annotations_typeArray, int &byte_i_ref, 1942 const char * trace_mesg, TRAPS) { 1943 1944 address cp_index_addr = (address) 1945 annotations_typeArray->adr_at(byte_i_ref); 1946 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr); 1947 u2 new_cp_index = find_new_index(old_cp_index); 1948 if (new_cp_index != 0) { 1949 RC_TRACE_WITH_THREAD(0x02000000, THREAD, (trace_mesg, old_cp_index)); 1950 Bytes::put_Java_u2(cp_index_addr, new_cp_index); 1951 old_cp_index = new_cp_index; 1952 } 1953 byte_i_ref += 2; 1954 return old_cp_index; 1955 } 1956 PRAGMA_DIAG_POP 1957 1958 1959 // Rewrite constant pool references in the element_value portion of an 1960 // annotations_typeArray. This "structure" is from section 4.8.15.1 of 1961 // the 2nd-edition of the VM spec: 1962 // 1963 // struct element_value { 1964 // u1 tag; 1965 // union { 1966 // u2 const_value_index; 1967 // { 1968 // u2 type_name_index; 1969 // u2 const_name_index; 1970 // } enum_const_value; 1971 // u2 class_info_index; 1972 // annotation annotation_value; 1973 // struct { 1974 // u2 num_values; 1975 // element_value values[num_values]; 1976 // } array_value; 1977 // } value; 1978 // } 1979 // 1980 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value( 1981 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) { 1982 1983 if ((byte_i_ref + 1) > annotations_typeArray->length()) { 1984 // not enough room for a tag let alone the rest of an element_value 1985 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1986 ("length() is too small for a tag")); 1987 return false; 1988 } 1989 1990 u1 tag = annotations_typeArray->at(byte_i_ref); 1991 byte_i_ref++; 1992 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("tag='%c'", tag)); 1993 1994 switch (tag) { 1995 // These BaseType tag values are from Table 4.2 in VM spec: 1996 case 'B': // byte 1997 case 'C': // char 1998 case 'D': // double 1999 case 'F': // float 2000 case 'I': // int 2001 case 'J': // long 2002 case 'S': // short 2003 case 'Z': // boolean 2004 2005 // The remaining tag values are from Table 4.8 in the 2nd-edition of 2006 // the VM spec: 2007 case 's': 2008 { 2009 // For the above tag values (including the BaseType values), 2010 // value.const_value_index is right union field. 2011 2012 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2013 // not enough room for a const_value_index 2014 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2015 ("length() is too small for a const_value_index")); 2016 return false; 2017 } 2018 2019 u2 const_value_index = rewrite_cp_ref_in_annotation_data( 2020 annotations_typeArray, byte_i_ref, 2021 "mapped old const_value_index=%d", THREAD); 2022 2023 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2024 ("const_value_index=%d", const_value_index)); 2025 } break; 2026 2027 case 'e': 2028 { 2029 // for the above tag value, value.enum_const_value is right union field 2030 2031 if ((byte_i_ref + 4) > annotations_typeArray->length()) { 2032 // not enough room for a enum_const_value 2033 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2034 ("length() is too small for a enum_const_value")); 2035 return false; 2036 } 2037 2038 u2 type_name_index = rewrite_cp_ref_in_annotation_data( 2039 annotations_typeArray, byte_i_ref, 2040 "mapped old type_name_index=%d", THREAD); 2041 2042 u2 const_name_index = rewrite_cp_ref_in_annotation_data( 2043 annotations_typeArray, byte_i_ref, 2044 "mapped old const_name_index=%d", THREAD); 2045 2046 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2047 ("type_name_index=%d const_name_index=%d", type_name_index, 2048 const_name_index)); 2049 } break; 2050 2051 case 'c': 2052 { 2053 // for the above tag value, value.class_info_index is right union field 2054 2055 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2056 // not enough room for a class_info_index 2057 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2058 ("length() is too small for a class_info_index")); 2059 return false; 2060 } 2061 2062 u2 class_info_index = rewrite_cp_ref_in_annotation_data( 2063 annotations_typeArray, byte_i_ref, 2064 "mapped old class_info_index=%d", THREAD); 2065 2066 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2067 ("class_info_index=%d", class_info_index)); 2068 } break; 2069 2070 case '@': 2071 // For the above tag value, value.attr_value is the right union 2072 // field. This is a nested annotation. 2073 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, 2074 byte_i_ref, THREAD)) { 2075 // propagate failure back to caller 2076 return false; 2077 } 2078 break; 2079 2080 case '[': 2081 { 2082 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2083 // not enough room for a num_values field 2084 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2085 ("length() is too small for a num_values field")); 2086 return false; 2087 } 2088 2089 // For the above tag value, value.array_value is the right union 2090 // field. This is an array of nested element_value. 2091 u2 num_values = Bytes::get_Java_u2((address) 2092 annotations_typeArray->adr_at(byte_i_ref)); 2093 byte_i_ref += 2; 2094 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("num_values=%d", num_values)); 2095 2096 int calc_num_values = 0; 2097 for (; calc_num_values < num_values; calc_num_values++) { 2098 if (!rewrite_cp_refs_in_element_value( 2099 annotations_typeArray, byte_i_ref, THREAD)) { 2100 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2101 ("bad nested element_value at %d", calc_num_values)); 2102 // propagate failure back to caller 2103 return false; 2104 } 2105 } 2106 assert(num_values == calc_num_values, "sanity check"); 2107 } break; 2108 2109 default: 2110 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("bad tag=0x%x", tag)); 2111 return false; 2112 } // end decode tag field 2113 2114 return true; 2115 } // end rewrite_cp_refs_in_element_value() 2116 2117 2118 // Rewrite constant pool references in a fields_annotations field. 2119 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations( 2120 instanceKlassHandle scratch_class, TRAPS) { 2121 2122 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations(); 2123 2124 if (fields_annotations == NULL || fields_annotations->length() == 0) { 2125 // no fields_annotations so nothing to do 2126 return true; 2127 } 2128 2129 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2130 ("fields_annotations length=%d", fields_annotations->length())); 2131 2132 for (int i = 0; i < fields_annotations->length(); i++) { 2133 AnnotationArray* field_annotations = fields_annotations->at(i); 2134 if (field_annotations == NULL || field_annotations->length() == 0) { 2135 // this field does not have any annotations so skip it 2136 continue; 2137 } 2138 2139 int byte_i = 0; // byte index into field_annotations 2140 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i, 2141 THREAD)) { 2142 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2143 ("bad field_annotations at %d", i)); 2144 // propagate failure back to caller 2145 return false; 2146 } 2147 } 2148 2149 return true; 2150 } // end rewrite_cp_refs_in_fields_annotations() 2151 2152 2153 // Rewrite constant pool references in a methods_annotations field. 2154 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations( 2155 instanceKlassHandle scratch_class, TRAPS) { 2156 2157 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2158 Method* m = scratch_class->methods()->at(i); 2159 AnnotationArray* method_annotations = m->constMethod()->method_annotations(); 2160 2161 if (method_annotations == NULL || method_annotations->length() == 0) { 2162 // this method does not have any annotations so skip it 2163 continue; 2164 } 2165 2166 int byte_i = 0; // byte index into method_annotations 2167 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i, 2168 THREAD)) { 2169 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2170 ("bad method_annotations at %d", i)); 2171 // propagate failure back to caller 2172 return false; 2173 } 2174 } 2175 2176 return true; 2177 } // end rewrite_cp_refs_in_methods_annotations() 2178 2179 2180 // Rewrite constant pool references in a methods_parameter_annotations 2181 // field. This "structure" is adapted from the 2182 // RuntimeVisibleParameterAnnotations_attribute described in section 2183 // 4.8.17 of the 2nd-edition of the VM spec: 2184 // 2185 // methods_parameter_annotations_typeArray { 2186 // u1 num_parameters; 2187 // { 2188 // u2 num_annotations; 2189 // annotation annotations[num_annotations]; 2190 // } parameter_annotations[num_parameters]; 2191 // } 2192 // 2193 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations( 2194 instanceKlassHandle scratch_class, TRAPS) { 2195 2196 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2197 Method* m = scratch_class->methods()->at(i); 2198 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations(); 2199 if (method_parameter_annotations == NULL 2200 || method_parameter_annotations->length() == 0) { 2201 // this method does not have any parameter annotations so skip it 2202 continue; 2203 } 2204 2205 if (method_parameter_annotations->length() < 1) { 2206 // not enough room for a num_parameters field 2207 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2208 ("length() is too small for a num_parameters field at %d", i)); 2209 return false; 2210 } 2211 2212 int byte_i = 0; // byte index into method_parameter_annotations 2213 2214 u1 num_parameters = method_parameter_annotations->at(byte_i); 2215 byte_i++; 2216 2217 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2218 ("num_parameters=%d", num_parameters)); 2219 2220 int calc_num_parameters = 0; 2221 for (; calc_num_parameters < num_parameters; calc_num_parameters++) { 2222 if (!rewrite_cp_refs_in_annotations_typeArray( 2223 method_parameter_annotations, byte_i, THREAD)) { 2224 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2225 ("bad method_parameter_annotations at %d", calc_num_parameters)); 2226 // propagate failure back to caller 2227 return false; 2228 } 2229 } 2230 assert(num_parameters == calc_num_parameters, "sanity check"); 2231 } 2232 2233 return true; 2234 } // end rewrite_cp_refs_in_methods_parameter_annotations() 2235 2236 2237 // Rewrite constant pool references in a methods_default_annotations 2238 // field. This "structure" is adapted from the AnnotationDefault_attribute 2239 // that is described in section 4.8.19 of the 2nd-edition of the VM spec: 2240 // 2241 // methods_default_annotations_typeArray { 2242 // element_value default_value; 2243 // } 2244 // 2245 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations( 2246 instanceKlassHandle scratch_class, TRAPS) { 2247 2248 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2249 Method* m = scratch_class->methods()->at(i); 2250 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations(); 2251 if (method_default_annotations == NULL 2252 || method_default_annotations->length() == 0) { 2253 // this method does not have any default annotations so skip it 2254 continue; 2255 } 2256 2257 int byte_i = 0; // byte index into method_default_annotations 2258 2259 if (!rewrite_cp_refs_in_element_value( 2260 method_default_annotations, byte_i, THREAD)) { 2261 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2262 ("bad default element_value at %d", i)); 2263 // propagate failure back to caller 2264 return false; 2265 } 2266 } 2267 2268 return true; 2269 } // end rewrite_cp_refs_in_methods_default_annotations() 2270 2271 2272 // Rewrite constant pool references in a class_type_annotations field. 2273 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations( 2274 instanceKlassHandle scratch_class, TRAPS) { 2275 2276 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations(); 2277 if (class_type_annotations == NULL || class_type_annotations->length() == 0) { 2278 // no class_type_annotations so nothing to do 2279 return true; 2280 } 2281 2282 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2283 ("class_type_annotations length=%d", class_type_annotations->length())); 2284 2285 int byte_i = 0; // byte index into class_type_annotations 2286 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations, 2287 byte_i, "ClassFile", THREAD); 2288 } // end rewrite_cp_refs_in_class_type_annotations() 2289 2290 2291 // Rewrite constant pool references in a fields_type_annotations field. 2292 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations( 2293 instanceKlassHandle scratch_class, TRAPS) { 2294 2295 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations(); 2296 if (fields_type_annotations == NULL || fields_type_annotations->length() == 0) { 2297 // no fields_type_annotations so nothing to do 2298 return true; 2299 } 2300 2301 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2302 ("fields_type_annotations length=%d", fields_type_annotations->length())); 2303 2304 for (int i = 0; i < fields_type_annotations->length(); i++) { 2305 AnnotationArray* field_type_annotations = fields_type_annotations->at(i); 2306 if (field_type_annotations == NULL || field_type_annotations->length() == 0) { 2307 // this field does not have any annotations so skip it 2308 continue; 2309 } 2310 2311 int byte_i = 0; // byte index into field_type_annotations 2312 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations, 2313 byte_i, "field_info", THREAD)) { 2314 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2315 ("bad field_type_annotations at %d", i)); 2316 // propagate failure back to caller 2317 return false; 2318 } 2319 } 2320 2321 return true; 2322 } // end rewrite_cp_refs_in_fields_type_annotations() 2323 2324 2325 // Rewrite constant pool references in a methods_type_annotations field. 2326 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations( 2327 instanceKlassHandle scratch_class, TRAPS) { 2328 2329 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2330 Method* m = scratch_class->methods()->at(i); 2331 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations(); 2332 2333 if (method_type_annotations == NULL || method_type_annotations->length() == 0) { 2334 // this method does not have any annotations so skip it 2335 continue; 2336 } 2337 2338 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2339 ("methods type_annotations length=%d", method_type_annotations->length())); 2340 2341 int byte_i = 0; // byte index into method_type_annotations 2342 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations, 2343 byte_i, "method_info", THREAD)) { 2344 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2345 ("bad method_type_annotations at %d", i)); 2346 // propagate failure back to caller 2347 return false; 2348 } 2349 } 2350 2351 return true; 2352 } // end rewrite_cp_refs_in_methods_type_annotations() 2353 2354 2355 // Rewrite constant pool references in a type_annotations 2356 // field. This "structure" is adapted from the 2357 // RuntimeVisibleTypeAnnotations_attribute described in 2358 // section 4.7.20 of the Java SE 8 Edition of the VM spec: 2359 // 2360 // type_annotations_typeArray { 2361 // u2 num_annotations; 2362 // type_annotation annotations[num_annotations]; 2363 // } 2364 // 2365 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray( 2366 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2367 const char * location_mesg, TRAPS) { 2368 2369 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2370 // not enough room for num_annotations field 2371 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2372 ("length() is too small for num_annotations field")); 2373 return false; 2374 } 2375 2376 u2 num_annotations = Bytes::get_Java_u2((address) 2377 type_annotations_typeArray->adr_at(byte_i_ref)); 2378 byte_i_ref += 2; 2379 2380 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2381 ("num_type_annotations=%d", num_annotations)); 2382 2383 int calc_num_annotations = 0; 2384 for (; calc_num_annotations < num_annotations; calc_num_annotations++) { 2385 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray, 2386 byte_i_ref, location_mesg, THREAD)) { 2387 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2388 ("bad type_annotation_struct at %d", calc_num_annotations)); 2389 // propagate failure back to caller 2390 return false; 2391 } 2392 } 2393 assert(num_annotations == calc_num_annotations, "sanity check"); 2394 2395 if (byte_i_ref != type_annotations_typeArray->length()) { 2396 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2397 ("read wrong amount of bytes at end of processing " 2398 "type_annotations_typeArray (%d of %d bytes were read)", 2399 byte_i_ref, type_annotations_typeArray->length())); 2400 return false; 2401 } 2402 2403 return true; 2404 } // end rewrite_cp_refs_in_type_annotations_typeArray() 2405 2406 2407 // Rewrite constant pool references in a type_annotation 2408 // field. This "structure" is adapted from the 2409 // RuntimeVisibleTypeAnnotations_attribute described in 2410 // section 4.7.20 of the Java SE 8 Edition of the VM spec: 2411 // 2412 // type_annotation { 2413 // u1 target_type; 2414 // union { 2415 // type_parameter_target; 2416 // supertype_target; 2417 // type_parameter_bound_target; 2418 // empty_target; 2419 // method_formal_parameter_target; 2420 // throws_target; 2421 // localvar_target; 2422 // catch_target; 2423 // offset_target; 2424 // type_argument_target; 2425 // } target_info; 2426 // type_path target_path; 2427 // annotation anno; 2428 // } 2429 // 2430 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct( 2431 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2432 const char * location_mesg, TRAPS) { 2433 2434 if (!skip_type_annotation_target(type_annotations_typeArray, 2435 byte_i_ref, location_mesg, THREAD)) { 2436 return false; 2437 } 2438 2439 if (!skip_type_annotation_type_path(type_annotations_typeArray, 2440 byte_i_ref, THREAD)) { 2441 return false; 2442 } 2443 2444 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray, 2445 byte_i_ref, THREAD)) { 2446 return false; 2447 } 2448 2449 return true; 2450 } // end rewrite_cp_refs_in_type_annotation_struct() 2451 2452 2453 // Read, verify and skip over the target_type and target_info part 2454 // so that rewriting can continue in the later parts of the struct. 2455 // 2456 // u1 target_type; 2457 // union { 2458 // type_parameter_target; 2459 // supertype_target; 2460 // type_parameter_bound_target; 2461 // empty_target; 2462 // method_formal_parameter_target; 2463 // throws_target; 2464 // localvar_target; 2465 // catch_target; 2466 // offset_target; 2467 // type_argument_target; 2468 // } target_info; 2469 // 2470 bool VM_RedefineClasses::skip_type_annotation_target( 2471 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2472 const char * location_mesg, TRAPS) { 2473 2474 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2475 // not enough room for a target_type let alone the rest of a type_annotation 2476 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2477 ("length() is too small for a target_type")); 2478 return false; 2479 } 2480 2481 u1 target_type = type_annotations_typeArray->at(byte_i_ref); 2482 byte_i_ref += 1; 2483 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("target_type=0x%.2x", target_type)); 2484 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("location=%s", location_mesg)); 2485 2486 // Skip over target_info 2487 switch (target_type) { 2488 case 0x00: 2489 // kind: type parameter declaration of generic class or interface 2490 // location: ClassFile 2491 case 0x01: 2492 // kind: type parameter declaration of generic method or constructor 2493 // location: method_info 2494 2495 { 2496 // struct: 2497 // type_parameter_target { 2498 // u1 type_parameter_index; 2499 // } 2500 // 2501 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2502 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2503 ("length() is too small for a type_parameter_target")); 2504 return false; 2505 } 2506 2507 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2508 byte_i_ref += 1; 2509 2510 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2511 ("type_parameter_target: type_parameter_index=%d", 2512 type_parameter_index)); 2513 } break; 2514 2515 case 0x10: 2516 // kind: type in extends clause of class or interface declaration 2517 // (including the direct superclass of an anonymous class declaration), 2518 // or in implements clause of interface declaration 2519 // location: ClassFile 2520 2521 { 2522 // struct: 2523 // supertype_target { 2524 // u2 supertype_index; 2525 // } 2526 // 2527 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2528 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2529 ("length() is too small for a supertype_target")); 2530 return false; 2531 } 2532 2533 u2 supertype_index = Bytes::get_Java_u2((address) 2534 type_annotations_typeArray->adr_at(byte_i_ref)); 2535 byte_i_ref += 2; 2536 2537 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2538 ("supertype_target: supertype_index=%d", supertype_index)); 2539 } break; 2540 2541 case 0x11: 2542 // kind: type in bound of type parameter declaration of generic class or interface 2543 // location: ClassFile 2544 case 0x12: 2545 // kind: type in bound of type parameter declaration of generic method or constructor 2546 // location: method_info 2547 2548 { 2549 // struct: 2550 // type_parameter_bound_target { 2551 // u1 type_parameter_index; 2552 // u1 bound_index; 2553 // } 2554 // 2555 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2556 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2557 ("length() is too small for a type_parameter_bound_target")); 2558 return false; 2559 } 2560 2561 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2562 byte_i_ref += 1; 2563 u1 bound_index = type_annotations_typeArray->at(byte_i_ref); 2564 byte_i_ref += 1; 2565 2566 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2567 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d", 2568 type_parameter_index, bound_index)); 2569 } break; 2570 2571 case 0x13: 2572 // kind: type in field declaration 2573 // location: field_info 2574 case 0x14: 2575 // kind: return type of method, or type of newly constructed object 2576 // location: method_info 2577 case 0x15: 2578 // kind: receiver type of method or constructor 2579 // location: method_info 2580 2581 { 2582 // struct: 2583 // empty_target { 2584 // } 2585 // 2586 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2587 ("empty_target")); 2588 } break; 2589 2590 case 0x16: 2591 // kind: type in formal parameter declaration of method, constructor, or lambda expression 2592 // location: method_info 2593 2594 { 2595 // struct: 2596 // formal_parameter_target { 2597 // u1 formal_parameter_index; 2598 // } 2599 // 2600 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2601 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2602 ("length() is too small for a formal_parameter_target")); 2603 return false; 2604 } 2605 2606 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2607 byte_i_ref += 1; 2608 2609 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2610 ("formal_parameter_target: formal_parameter_index=%d", 2611 formal_parameter_index)); 2612 } break; 2613 2614 case 0x17: 2615 // kind: type in throws clause of method or constructor 2616 // location: method_info 2617 2618 { 2619 // struct: 2620 // throws_target { 2621 // u2 throws_type_index 2622 // } 2623 // 2624 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2625 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2626 ("length() is too small for a throws_target")); 2627 return false; 2628 } 2629 2630 u2 throws_type_index = Bytes::get_Java_u2((address) 2631 type_annotations_typeArray->adr_at(byte_i_ref)); 2632 byte_i_ref += 2; 2633 2634 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2635 ("throws_target: throws_type_index=%d", throws_type_index)); 2636 } break; 2637 2638 case 0x40: 2639 // kind: type in local variable declaration 2640 // location: Code 2641 case 0x41: 2642 // kind: type in resource variable declaration 2643 // location: Code 2644 2645 { 2646 // struct: 2647 // localvar_target { 2648 // u2 table_length; 2649 // struct { 2650 // u2 start_pc; 2651 // u2 length; 2652 // u2 index; 2653 // } table[table_length]; 2654 // } 2655 // 2656 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2657 // not enough room for a table_length let alone the rest of a localvar_target 2658 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2659 ("length() is too small for a localvar_target table_length")); 2660 return false; 2661 } 2662 2663 u2 table_length = Bytes::get_Java_u2((address) 2664 type_annotations_typeArray->adr_at(byte_i_ref)); 2665 byte_i_ref += 2; 2666 2667 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2668 ("localvar_target: table_length=%d", table_length)); 2669 2670 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry 2671 int table_size = table_length * table_struct_size; 2672 2673 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) { 2674 // not enough room for a table 2675 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2676 ("length() is too small for a table array of length %d", table_length)); 2677 return false; 2678 } 2679 2680 // Skip over table 2681 byte_i_ref += table_size; 2682 } break; 2683 2684 case 0x42: 2685 // kind: type in exception parameter declaration 2686 // location: Code 2687 2688 { 2689 // struct: 2690 // catch_target { 2691 // u2 exception_table_index; 2692 // } 2693 // 2694 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2695 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2696 ("length() is too small for a catch_target")); 2697 return false; 2698 } 2699 2700 u2 exception_table_index = Bytes::get_Java_u2((address) 2701 type_annotations_typeArray->adr_at(byte_i_ref)); 2702 byte_i_ref += 2; 2703 2704 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2705 ("catch_target: exception_table_index=%d", exception_table_index)); 2706 } break; 2707 2708 case 0x43: 2709 // kind: type in instanceof expression 2710 // location: Code 2711 case 0x44: 2712 // kind: type in new expression 2713 // location: Code 2714 case 0x45: 2715 // kind: type in method reference expression using ::new 2716 // location: Code 2717 case 0x46: 2718 // kind: type in method reference expression using ::Identifier 2719 // location: Code 2720 2721 { 2722 // struct: 2723 // offset_target { 2724 // u2 offset; 2725 // } 2726 // 2727 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2728 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2729 ("length() is too small for a offset_target")); 2730 return false; 2731 } 2732 2733 u2 offset = Bytes::get_Java_u2((address) 2734 type_annotations_typeArray->adr_at(byte_i_ref)); 2735 byte_i_ref += 2; 2736 2737 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2738 ("offset_target: offset=%d", offset)); 2739 } break; 2740 2741 case 0x47: 2742 // kind: type in cast expression 2743 // location: Code 2744 case 0x48: 2745 // kind: type argument for generic constructor in new expression or 2746 // explicit constructor invocation statement 2747 // location: Code 2748 case 0x49: 2749 // kind: type argument for generic method in method invocation expression 2750 // location: Code 2751 case 0x4A: 2752 // kind: type argument for generic constructor in method reference expression using ::new 2753 // location: Code 2754 case 0x4B: 2755 // kind: type argument for generic method in method reference expression using ::Identifier 2756 // location: Code 2757 2758 { 2759 // struct: 2760 // type_argument_target { 2761 // u2 offset; 2762 // u1 type_argument_index; 2763 // } 2764 // 2765 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) { 2766 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2767 ("length() is too small for a type_argument_target")); 2768 return false; 2769 } 2770 2771 u2 offset = Bytes::get_Java_u2((address) 2772 type_annotations_typeArray->adr_at(byte_i_ref)); 2773 byte_i_ref += 2; 2774 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref); 2775 byte_i_ref += 1; 2776 2777 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2778 ("type_argument_target: offset=%d, type_argument_index=%d", 2779 offset, type_argument_index)); 2780 } break; 2781 2782 default: 2783 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2784 ("unknown target_type")); 2785 #ifdef ASSERT 2786 ShouldNotReachHere(); 2787 #endif 2788 return false; 2789 } 2790 2791 return true; 2792 } // end skip_type_annotation_target() 2793 2794 2795 // Read, verify and skip over the type_path part so that rewriting 2796 // can continue in the later parts of the struct. 2797 // 2798 // type_path { 2799 // u1 path_length; 2800 // { 2801 // u1 type_path_kind; 2802 // u1 type_argument_index; 2803 // } path[path_length]; 2804 // } 2805 // 2806 bool VM_RedefineClasses::skip_type_annotation_type_path( 2807 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, TRAPS) { 2808 2809 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2810 // not enough room for a path_length let alone the rest of the type_path 2811 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2812 ("length() is too small for a type_path")); 2813 return false; 2814 } 2815 2816 u1 path_length = type_annotations_typeArray->at(byte_i_ref); 2817 byte_i_ref += 1; 2818 2819 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2820 ("type_path: path_length=%d", path_length)); 2821 2822 int calc_path_length = 0; 2823 for (; calc_path_length < path_length; calc_path_length++) { 2824 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) { 2825 // not enough room for a path 2826 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2827 ("length() is too small for path entry %d of %d", 2828 calc_path_length, path_length)); 2829 return false; 2830 } 2831 2832 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref); 2833 byte_i_ref += 1; 2834 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref); 2835 byte_i_ref += 1; 2836 2837 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2838 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d", 2839 calc_path_length, type_path_kind, type_argument_index)); 2840 2841 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) { 2842 // not enough room for a path 2843 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2844 ("inconsistent type_path values")); 2845 return false; 2846 } 2847 } 2848 assert(path_length == calc_path_length, "sanity check"); 2849 2850 return true; 2851 } // end skip_type_annotation_type_path() 2852 2853 2854 // Rewrite constant pool references in the method's stackmap table. 2855 // These "structures" are adapted from the StackMapTable_attribute that 2856 // is described in section 4.8.4 of the 6.0 version of the VM spec 2857 // (dated 2005.10.26): 2858 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf 2859 // 2860 // stack_map { 2861 // u2 number_of_entries; 2862 // stack_map_frame entries[number_of_entries]; 2863 // } 2864 // 2865 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table( 2866 methodHandle method, TRAPS) { 2867 2868 if (!method->has_stackmap_table()) { 2869 return; 2870 } 2871 2872 AnnotationArray* stackmap_data = method->stackmap_data(); 2873 address stackmap_p = (address)stackmap_data->adr_at(0); 2874 address stackmap_end = stackmap_p + stackmap_data->length(); 2875 2876 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries"); 2877 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p); 2878 stackmap_p += 2; 2879 2880 RC_TRACE_WITH_THREAD(0x04000000, THREAD, 2881 ("number_of_entries=%u", number_of_entries)); 2882 2883 // walk through each stack_map_frame 2884 u2 calc_number_of_entries = 0; 2885 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) { 2886 // The stack_map_frame structure is a u1 frame_type followed by 2887 // 0 or more bytes of data: 2888 // 2889 // union stack_map_frame { 2890 // same_frame; 2891 // same_locals_1_stack_item_frame; 2892 // same_locals_1_stack_item_frame_extended; 2893 // chop_frame; 2894 // same_frame_extended; 2895 // append_frame; 2896 // full_frame; 2897 // } 2898 2899 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type"); 2900 // The Linux compiler does not like frame_type to be u1 or u2. It 2901 // issues the following warning for the first if-statement below: 2902 // 2903 // "warning: comparison is always true due to limited range of data type" 2904 // 2905 u4 frame_type = *stackmap_p; 2906 stackmap_p++; 2907 2908 // same_frame { 2909 // u1 frame_type = SAME; /* 0-63 */ 2910 // } 2911 if (frame_type >= 0 && frame_type <= 63) { 2912 // nothing more to do for same_frame 2913 } 2914 2915 // same_locals_1_stack_item_frame { 2916 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */ 2917 // verification_type_info stack[1]; 2918 // } 2919 else if (frame_type >= 64 && frame_type <= 127) { 2920 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2921 calc_number_of_entries, frame_type, THREAD); 2922 } 2923 2924 // reserved for future use 2925 else if (frame_type >= 128 && frame_type <= 246) { 2926 // nothing more to do for reserved frame_types 2927 } 2928 2929 // same_locals_1_stack_item_frame_extended { 2930 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */ 2931 // u2 offset_delta; 2932 // verification_type_info stack[1]; 2933 // } 2934 else if (frame_type == 247) { 2935 stackmap_p += 2; 2936 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2937 calc_number_of_entries, frame_type, THREAD); 2938 } 2939 2940 // chop_frame { 2941 // u1 frame_type = CHOP; /* 248-250 */ 2942 // u2 offset_delta; 2943 // } 2944 else if (frame_type >= 248 && frame_type <= 250) { 2945 stackmap_p += 2; 2946 } 2947 2948 // same_frame_extended { 2949 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/ 2950 // u2 offset_delta; 2951 // } 2952 else if (frame_type == 251) { 2953 stackmap_p += 2; 2954 } 2955 2956 // append_frame { 2957 // u1 frame_type = APPEND; /* 252-254 */ 2958 // u2 offset_delta; 2959 // verification_type_info locals[frame_type - 251]; 2960 // } 2961 else if (frame_type >= 252 && frame_type <= 254) { 2962 assert(stackmap_p + 2 <= stackmap_end, 2963 "no room for offset_delta"); 2964 stackmap_p += 2; 2965 u1 len = frame_type - 251; 2966 for (u1 i = 0; i < len; i++) { 2967 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2968 calc_number_of_entries, frame_type, THREAD); 2969 } 2970 } 2971 2972 // full_frame { 2973 // u1 frame_type = FULL_FRAME; /* 255 */ 2974 // u2 offset_delta; 2975 // u2 number_of_locals; 2976 // verification_type_info locals[number_of_locals]; 2977 // u2 number_of_stack_items; 2978 // verification_type_info stack[number_of_stack_items]; 2979 // } 2980 else if (frame_type == 255) { 2981 assert(stackmap_p + 2 + 2 <= stackmap_end, 2982 "no room for smallest full_frame"); 2983 stackmap_p += 2; 2984 2985 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p); 2986 stackmap_p += 2; 2987 2988 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) { 2989 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2990 calc_number_of_entries, frame_type, THREAD); 2991 } 2992 2993 // Use the largest size for the number_of_stack_items, but only get 2994 // the right number of bytes. 2995 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p); 2996 stackmap_p += 2; 2997 2998 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) { 2999 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3000 calc_number_of_entries, frame_type, THREAD); 3001 } 3002 } 3003 } // end while there is a stack_map_frame 3004 assert(number_of_entries == calc_number_of_entries, "sanity check"); 3005 } // end rewrite_cp_refs_in_stack_map_table() 3006 3007 3008 // Rewrite constant pool references in the verification type info 3009 // portion of the method's stackmap table. These "structures" are 3010 // adapted from the StackMapTable_attribute that is described in 3011 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26): 3012 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf 3013 // 3014 // The verification_type_info structure is a u1 tag followed by 0 or 3015 // more bytes of data: 3016 // 3017 // union verification_type_info { 3018 // Top_variable_info; 3019 // Integer_variable_info; 3020 // Float_variable_info; 3021 // Long_variable_info; 3022 // Double_variable_info; 3023 // Null_variable_info; 3024 // UninitializedThis_variable_info; 3025 // Object_variable_info; 3026 // Uninitialized_variable_info; 3027 // } 3028 // 3029 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info( 3030 address& stackmap_p_ref, address stackmap_end, u2 frame_i, 3031 u1 frame_type, TRAPS) { 3032 3033 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag"); 3034 u1 tag = *stackmap_p_ref; 3035 stackmap_p_ref++; 3036 3037 switch (tag) { 3038 // Top_variable_info { 3039 // u1 tag = ITEM_Top; /* 0 */ 3040 // } 3041 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top 3042 case 0: // fall through 3043 3044 // Integer_variable_info { 3045 // u1 tag = ITEM_Integer; /* 1 */ 3046 // } 3047 case ITEM_Integer: // fall through 3048 3049 // Float_variable_info { 3050 // u1 tag = ITEM_Float; /* 2 */ 3051 // } 3052 case ITEM_Float: // fall through 3053 3054 // Double_variable_info { 3055 // u1 tag = ITEM_Double; /* 3 */ 3056 // } 3057 case ITEM_Double: // fall through 3058 3059 // Long_variable_info { 3060 // u1 tag = ITEM_Long; /* 4 */ 3061 // } 3062 case ITEM_Long: // fall through 3063 3064 // Null_variable_info { 3065 // u1 tag = ITEM_Null; /* 5 */ 3066 // } 3067 case ITEM_Null: // fall through 3068 3069 // UninitializedThis_variable_info { 3070 // u1 tag = ITEM_UninitializedThis; /* 6 */ 3071 // } 3072 case ITEM_UninitializedThis: 3073 // nothing more to do for the above tag types 3074 break; 3075 3076 // Object_variable_info { 3077 // u1 tag = ITEM_Object; /* 7 */ 3078 // u2 cpool_index; 3079 // } 3080 case ITEM_Object: 3081 { 3082 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index"); 3083 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref); 3084 u2 new_cp_index = find_new_index(cpool_index); 3085 if (new_cp_index != 0) { 3086 RC_TRACE_WITH_THREAD(0x04000000, THREAD, 3087 ("mapped old cpool_index=%d", cpool_index)); 3088 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index); 3089 cpool_index = new_cp_index; 3090 } 3091 stackmap_p_ref += 2; 3092 3093 RC_TRACE_WITH_THREAD(0x04000000, THREAD, 3094 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i, 3095 frame_type, cpool_index)); 3096 } break; 3097 3098 // Uninitialized_variable_info { 3099 // u1 tag = ITEM_Uninitialized; /* 8 */ 3100 // u2 offset; 3101 // } 3102 case ITEM_Uninitialized: 3103 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset"); 3104 stackmap_p_ref += 2; 3105 break; 3106 3107 default: 3108 RC_TRACE_WITH_THREAD(0x04000000, THREAD, 3109 ("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag)); 3110 ShouldNotReachHere(); 3111 break; 3112 } // end switch (tag) 3113 } // end rewrite_cp_refs_in_verification_type_info() 3114 3115 3116 // Change the constant pool associated with klass scratch_class to 3117 // scratch_cp. If shrink is true, then scratch_cp_length elements 3118 // are copied from scratch_cp to a smaller constant pool and the 3119 // smaller constant pool is associated with scratch_class. 3120 void VM_RedefineClasses::set_new_constant_pool( 3121 ClassLoaderData* loader_data, 3122 instanceKlassHandle scratch_class, constantPoolHandle scratch_cp, 3123 int scratch_cp_length, TRAPS) { 3124 assert(scratch_cp->length() >= scratch_cp_length, "sanity check"); 3125 3126 // scratch_cp is a merged constant pool and has enough space for a 3127 // worst case merge situation. We want to associate the minimum 3128 // sized constant pool with the klass to save space. 3129 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK); 3130 constantPoolHandle smaller_cp(THREAD, cp); 3131 3132 // preserve version() value in the smaller copy 3133 int version = scratch_cp->version(); 3134 assert(version != 0, "sanity check"); 3135 smaller_cp->set_version(version); 3136 3137 // attach klass to new constant pool 3138 // reference to the cp holder is needed for copy_operands() 3139 smaller_cp->set_pool_holder(scratch_class()); 3140 3141 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD); 3142 if (HAS_PENDING_EXCEPTION) { 3143 // Exception is handled in the caller 3144 loader_data->add_to_deallocate_list(smaller_cp()); 3145 return; 3146 } 3147 scratch_cp = smaller_cp; 3148 3149 // attach new constant pool to klass 3150 scratch_class->set_constants(scratch_cp()); 3151 3152 int i; // for portability 3153 3154 // update each field in klass to use new constant pool indices as needed 3155 for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) { 3156 jshort cur_index = fs.name_index(); 3157 jshort new_index = find_new_index(cur_index); 3158 if (new_index != 0) { 3159 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3160 ("field-name_index change: %d to %d", cur_index, new_index)); 3161 fs.set_name_index(new_index); 3162 } 3163 cur_index = fs.signature_index(); 3164 new_index = find_new_index(cur_index); 3165 if (new_index != 0) { 3166 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3167 ("field-signature_index change: %d to %d", cur_index, new_index)); 3168 fs.set_signature_index(new_index); 3169 } 3170 cur_index = fs.initval_index(); 3171 new_index = find_new_index(cur_index); 3172 if (new_index != 0) { 3173 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3174 ("field-initval_index change: %d to %d", cur_index, new_index)); 3175 fs.set_initval_index(new_index); 3176 } 3177 cur_index = fs.generic_signature_index(); 3178 new_index = find_new_index(cur_index); 3179 if (new_index != 0) { 3180 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3181 ("field-generic_signature change: %d to %d", cur_index, new_index)); 3182 fs.set_generic_signature_index(new_index); 3183 } 3184 } // end for each field 3185 3186 // Update constant pool indices in the inner classes info to use 3187 // new constant indices as needed. The inner classes info is a 3188 // quadruple: 3189 // (inner_class_info, outer_class_info, inner_name, inner_access_flags) 3190 InnerClassesIterator iter(scratch_class); 3191 for (; !iter.done(); iter.next()) { 3192 int cur_index = iter.inner_class_info_index(); 3193 if (cur_index == 0) { 3194 continue; // JVM spec. allows null inner class refs so skip it 3195 } 3196 int new_index = find_new_index(cur_index); 3197 if (new_index != 0) { 3198 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3199 ("inner_class_info change: %d to %d", cur_index, new_index)); 3200 iter.set_inner_class_info_index(new_index); 3201 } 3202 cur_index = iter.outer_class_info_index(); 3203 new_index = find_new_index(cur_index); 3204 if (new_index != 0) { 3205 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3206 ("outer_class_info change: %d to %d", cur_index, new_index)); 3207 iter.set_outer_class_info_index(new_index); 3208 } 3209 cur_index = iter.inner_name_index(); 3210 new_index = find_new_index(cur_index); 3211 if (new_index != 0) { 3212 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3213 ("inner_name change: %d to %d", cur_index, new_index)); 3214 iter.set_inner_name_index(new_index); 3215 } 3216 } // end for each inner class 3217 3218 // Attach each method in klass to the new constant pool and update 3219 // to use new constant pool indices as needed: 3220 Array<Method*>* methods = scratch_class->methods(); 3221 for (i = methods->length() - 1; i >= 0; i--) { 3222 methodHandle method(THREAD, methods->at(i)); 3223 method->set_constants(scratch_cp()); 3224 3225 int new_index = find_new_index(method->name_index()); 3226 if (new_index != 0) { 3227 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3228 ("method-name_index change: %d to %d", method->name_index(), 3229 new_index)); 3230 method->set_name_index(new_index); 3231 } 3232 new_index = find_new_index(method->signature_index()); 3233 if (new_index != 0) { 3234 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3235 ("method-signature_index change: %d to %d", 3236 method->signature_index(), new_index)); 3237 method->set_signature_index(new_index); 3238 } 3239 new_index = find_new_index(method->generic_signature_index()); 3240 if (new_index != 0) { 3241 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3242 ("method-generic_signature_index change: %d to %d", 3243 method->generic_signature_index(), new_index)); 3244 method->set_generic_signature_index(new_index); 3245 } 3246 3247 // Update constant pool indices in the method's checked exception 3248 // table to use new constant indices as needed. 3249 int cext_length = method->checked_exceptions_length(); 3250 if (cext_length > 0) { 3251 CheckedExceptionElement * cext_table = 3252 method->checked_exceptions_start(); 3253 for (int j = 0; j < cext_length; j++) { 3254 int cur_index = cext_table[j].class_cp_index; 3255 int new_index = find_new_index(cur_index); 3256 if (new_index != 0) { 3257 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3258 ("cext-class_cp_index change: %d to %d", cur_index, new_index)); 3259 cext_table[j].class_cp_index = (u2)new_index; 3260 } 3261 } // end for each checked exception table entry 3262 } // end if there are checked exception table entries 3263 3264 // Update each catch type index in the method's exception table 3265 // to use new constant pool indices as needed. The exception table 3266 // holds quadruple entries of the form: 3267 // (beg_bci, end_bci, handler_bci, klass_index) 3268 3269 ExceptionTable ex_table(method()); 3270 int ext_length = ex_table.length(); 3271 3272 for (int j = 0; j < ext_length; j ++) { 3273 int cur_index = ex_table.catch_type_index(j); 3274 int new_index = find_new_index(cur_index); 3275 if (new_index != 0) { 3276 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3277 ("ext-klass_index change: %d to %d", cur_index, new_index)); 3278 ex_table.set_catch_type_index(j, new_index); 3279 } 3280 } // end for each exception table entry 3281 3282 // Update constant pool indices in the method's local variable 3283 // table to use new constant indices as needed. The local variable 3284 // table hold sextuple entries of the form: 3285 // (start_pc, length, name_index, descriptor_index, signature_index, slot) 3286 int lvt_length = method->localvariable_table_length(); 3287 if (lvt_length > 0) { 3288 LocalVariableTableElement * lv_table = 3289 method->localvariable_table_start(); 3290 for (int j = 0; j < lvt_length; j++) { 3291 int cur_index = lv_table[j].name_cp_index; 3292 int new_index = find_new_index(cur_index); 3293 if (new_index != 0) { 3294 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3295 ("lvt-name_cp_index change: %d to %d", cur_index, new_index)); 3296 lv_table[j].name_cp_index = (u2)new_index; 3297 } 3298 cur_index = lv_table[j].descriptor_cp_index; 3299 new_index = find_new_index(cur_index); 3300 if (new_index != 0) { 3301 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3302 ("lvt-descriptor_cp_index change: %d to %d", cur_index, 3303 new_index)); 3304 lv_table[j].descriptor_cp_index = (u2)new_index; 3305 } 3306 cur_index = lv_table[j].signature_cp_index; 3307 new_index = find_new_index(cur_index); 3308 if (new_index != 0) { 3309 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3310 ("lvt-signature_cp_index change: %d to %d", cur_index, new_index)); 3311 lv_table[j].signature_cp_index = (u2)new_index; 3312 } 3313 } // end for each local variable table entry 3314 } // end if there are local variable table entries 3315 3316 rewrite_cp_refs_in_stack_map_table(method, THREAD); 3317 } // end for each method 3318 } // end set_new_constant_pool() 3319 3320 3321 // Unevolving classes may point to methods of the_class directly 3322 // from their constant pool caches, itables, and/or vtables. We 3323 // use the ClassLoaderDataGraph::classes_do() facility and this helper 3324 // to fix up these pointers. 3325 3326 // Adjust cpools and vtables closure 3327 void VM_RedefineClasses::AdjustCpoolCacheAndVtable::do_klass(Klass* k) { 3328 3329 // This is a very busy routine. We don't want too much tracing 3330 // printed out. 3331 bool trace_name_printed = false; 3332 InstanceKlass *the_class = InstanceKlass::cast(_the_class_oop); 3333 3334 // Very noisy: only enable this call if you are trying to determine 3335 // that a specific class gets found by this routine. 3336 // RC_TRACE macro has an embedded ResourceMark 3337 // RC_TRACE_WITH_THREAD(0x00100000, THREAD, 3338 // ("adjust check: name=%s", k->external_name())); 3339 // trace_name_printed = true; 3340 3341 // If the class being redefined is java.lang.Object, we need to fix all 3342 // array class vtables also 3343 if (k->oop_is_array() && _the_class_oop == SystemDictionary::Object_klass()) { 3344 k->vtable()->adjust_method_entries(the_class, &trace_name_printed); 3345 3346 } else if (k->oop_is_instance()) { 3347 HandleMark hm(_thread); 3348 InstanceKlass *ik = InstanceKlass::cast(k); 3349 3350 // HotSpot specific optimization! HotSpot does not currently 3351 // support delegation from the bootstrap class loader to a 3352 // user-defined class loader. This means that if the bootstrap 3353 // class loader is the initiating class loader, then it will also 3354 // be the defining class loader. This also means that classes 3355 // loaded by the bootstrap class loader cannot refer to classes 3356 // loaded by a user-defined class loader. Note: a user-defined 3357 // class loader can delegate to the bootstrap class loader. 3358 // 3359 // If the current class being redefined has a user-defined class 3360 // loader as its defining class loader, then we can skip all 3361 // classes loaded by the bootstrap class loader. 3362 bool is_user_defined = 3363 InstanceKlass::cast(_the_class_oop)->class_loader() != NULL; 3364 if (is_user_defined && ik->class_loader() == NULL) { 3365 return; 3366 } 3367 3368 // Fix the vtable embedded in the_class and subclasses of the_class, 3369 // if one exists. We discard scratch_class and we don't keep an 3370 // InstanceKlass around to hold obsolete methods so we don't have 3371 // any other InstanceKlass embedded vtables to update. The vtable 3372 // holds the Method*s for virtual (but not final) methods. 3373 // Default methods, or concrete methods in interfaces are stored 3374 // in the vtable, so if an interface changes we need to check 3375 // adjust_method_entries() for every InstanceKlass, which will also 3376 // adjust the default method vtable indices. 3377 // We also need to adjust any default method entries that are 3378 // not yet in the vtable, because the vtable setup is in progress. 3379 // This must be done after we adjust the default_methods and 3380 // default_vtable_indices for methods already in the vtable. 3381 if (ik->vtable_length() > 0 && (_the_class_oop->is_interface() 3382 || ik->is_subtype_of(_the_class_oop))) { 3383 // ik->vtable() creates a wrapper object; rm cleans it up 3384 ResourceMark rm(_thread); 3385 3386 ik->vtable()->adjust_method_entries(the_class, &trace_name_printed); 3387 ik->adjust_default_methods(the_class, &trace_name_printed); 3388 } 3389 3390 // If the current class has an itable and we are either redefining an 3391 // interface or if the current class is a subclass of the_class, then 3392 // we potentially have to fix the itable. If we are redefining an 3393 // interface, then we have to call adjust_method_entries() for 3394 // every InstanceKlass that has an itable since there isn't a 3395 // subclass relationship between an interface and an InstanceKlass. 3396 if (ik->itable_length() > 0 && (_the_class_oop->is_interface() 3397 || ik->is_subclass_of(_the_class_oop))) { 3398 // ik->itable() creates a wrapper object; rm cleans it up 3399 ResourceMark rm(_thread); 3400 3401 ik->itable()->adjust_method_entries(the_class, &trace_name_printed); 3402 } 3403 3404 // The constant pools in other classes (other_cp) can refer to 3405 // methods in the_class. We have to update method information in 3406 // other_cp's cache. If other_cp has a previous version, then we 3407 // have to repeat the process for each previous version. The 3408 // constant pool cache holds the Method*s for non-virtual 3409 // methods and for virtual, final methods. 3410 // 3411 // Special case: if the current class is the_class, then new_cp 3412 // has already been attached to the_class and old_cp has already 3413 // been added as a previous version. The new_cp doesn't have any 3414 // cached references to old methods so it doesn't need to be 3415 // updated. We can simply start with the previous version(s) in 3416 // that case. 3417 constantPoolHandle other_cp; 3418 ConstantPoolCache* cp_cache; 3419 3420 if (ik != _the_class_oop) { 3421 // this klass' constant pool cache may need adjustment 3422 other_cp = constantPoolHandle(ik->constants()); 3423 cp_cache = other_cp->cache(); 3424 if (cp_cache != NULL) { 3425 cp_cache->adjust_method_entries(the_class, &trace_name_printed); 3426 } 3427 } 3428 3429 // the previous versions' constant pool caches may need adjustment 3430 PreviousVersionWalker pvw(_thread, ik); 3431 for (PreviousVersionNode * pv_node = pvw.next_previous_version(); 3432 pv_node != NULL; pv_node = pvw.next_previous_version()) { 3433 other_cp = pv_node->prev_constant_pool(); 3434 cp_cache = other_cp->cache(); 3435 if (cp_cache != NULL) { 3436 cp_cache->adjust_method_entries(other_cp->pool_holder(), &trace_name_printed); 3437 } 3438 } 3439 } 3440 } 3441 3442 void VM_RedefineClasses::update_jmethod_ids() { 3443 for (int j = 0; j < _matching_methods_length; ++j) { 3444 Method* old_method = _matching_old_methods[j]; 3445 jmethodID jmid = old_method->find_jmethod_id_or_null(); 3446 if (jmid != NULL) { 3447 // There is a jmethodID, change it to point to the new method 3448 methodHandle new_method_h(_matching_new_methods[j]); 3449 Method::change_method_associated_with_jmethod_id(jmid, new_method_h()); 3450 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j], 3451 "should be replaced"); 3452 } 3453 } 3454 } 3455 3456 void VM_RedefineClasses::check_methods_and_mark_as_obsolete( 3457 BitMap *emcp_methods, int * emcp_method_count_p) { 3458 *emcp_method_count_p = 0; 3459 int obsolete_count = 0; 3460 int old_index = 0; 3461 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) { 3462 Method* old_method = _matching_old_methods[j]; 3463 Method* new_method = _matching_new_methods[j]; 3464 Method* old_array_method; 3465 3466 // Maintain an old_index into the _old_methods array by skipping 3467 // deleted methods 3468 while ((old_array_method = _old_methods->at(old_index)) != old_method) { 3469 ++old_index; 3470 } 3471 3472 if (MethodComparator::methods_EMCP(old_method, new_method)) { 3473 // The EMCP definition from JSR-163 requires the bytecodes to be 3474 // the same with the exception of constant pool indices which may 3475 // differ. However, the constants referred to by those indices 3476 // must be the same. 3477 // 3478 // We use methods_EMCP() for comparison since constant pool 3479 // merging can remove duplicate constant pool entries that were 3480 // present in the old method and removed from the rewritten new 3481 // method. A faster binary comparison function would consider the 3482 // old and new methods to be different when they are actually 3483 // EMCP. 3484 // 3485 // The old and new methods are EMCP and you would think that we 3486 // could get rid of one of them here and now and save some space. 3487 // However, the concept of EMCP only considers the bytecodes and 3488 // the constant pool entries in the comparison. Other things, 3489 // e.g., the line number table (LNT) or the local variable table 3490 // (LVT) don't count in the comparison. So the new (and EMCP) 3491 // method can have a new LNT that we need so we can't just 3492 // overwrite the new method with the old method. 3493 // 3494 // When this routine is called, we have already attached the new 3495 // methods to the_class so the old methods are effectively 3496 // overwritten. However, if an old method is still executing, 3497 // then the old method cannot be collected until sometime after 3498 // the old method call has returned. So the overwriting of old 3499 // methods by new methods will save us space except for those 3500 // (hopefully few) old methods that are still executing. 3501 // 3502 // A method refers to a ConstMethod* and this presents another 3503 // possible avenue to space savings. The ConstMethod* in the 3504 // new method contains possibly new attributes (LNT, LVT, etc). 3505 // At first glance, it seems possible to save space by replacing 3506 // the ConstMethod* in the old method with the ConstMethod* 3507 // from the new method. The old and new methods would share the 3508 // same ConstMethod* and we would save the space occupied by 3509 // the old ConstMethod*. However, the ConstMethod* contains 3510 // a back reference to the containing method. Sharing the 3511 // ConstMethod* between two methods could lead to confusion in 3512 // the code that uses the back reference. This would lead to 3513 // brittle code that could be broken in non-obvious ways now or 3514 // in the future. 3515 // 3516 // Another possibility is to copy the ConstMethod* from the new 3517 // method to the old method and then overwrite the new method with 3518 // the old method. Since the ConstMethod* contains the bytecodes 3519 // for the method embedded in the oop, this option would change 3520 // the bytecodes out from under any threads executing the old 3521 // method and make the thread's bcp invalid. Since EMCP requires 3522 // that the bytecodes be the same modulo constant pool indices, it 3523 // is straight forward to compute the correct new bcp in the new 3524 // ConstMethod* from the old bcp in the old ConstMethod*. The 3525 // time consuming part would be searching all the frames in all 3526 // of the threads to find all of the calls to the old method. 3527 // 3528 // It looks like we will have to live with the limited savings 3529 // that we get from effectively overwriting the old methods 3530 // when the new methods are attached to the_class. 3531 3532 // track which methods are EMCP for add_previous_version() call 3533 emcp_methods->set_bit(old_index); 3534 (*emcp_method_count_p)++; 3535 3536 // An EMCP method is _not_ obsolete. An obsolete method has a 3537 // different jmethodID than the current method. An EMCP method 3538 // has the same jmethodID as the current method. Having the 3539 // same jmethodID for all EMCP versions of a method allows for 3540 // a consistent view of the EMCP methods regardless of which 3541 // EMCP method you happen to have in hand. For example, a 3542 // breakpoint set in one EMCP method will work for all EMCP 3543 // versions of the method including the current one. 3544 } else { 3545 // mark obsolete methods as such 3546 old_method->set_is_obsolete(); 3547 obsolete_count++; 3548 3549 // obsolete methods need a unique idnum so they become new entries in 3550 // the jmethodID cache in InstanceKlass 3551 assert(old_method->method_idnum() == new_method->method_idnum(), "must match"); 3552 u2 num = InstanceKlass::cast(_the_class_oop)->next_method_idnum(); 3553 if (num != ConstMethod::UNSET_IDNUM) { 3554 old_method->set_method_idnum(num); 3555 } 3556 3557 // With tracing we try not to "yack" too much. The position of 3558 // this trace assumes there are fewer obsolete methods than 3559 // EMCP methods. 3560 RC_TRACE(0x00000100, ("mark %s(%s) as obsolete", 3561 old_method->name()->as_C_string(), 3562 old_method->signature()->as_C_string())); 3563 } 3564 old_method->set_is_old(); 3565 } 3566 for (int i = 0; i < _deleted_methods_length; ++i) { 3567 Method* old_method = _deleted_methods[i]; 3568 3569 assert(!old_method->has_vtable_index(), 3570 "cannot delete methods with vtable entries");; 3571 3572 // Mark all deleted methods as old, obsolete and deleted 3573 old_method->set_is_deleted(); 3574 old_method->set_is_old(); 3575 old_method->set_is_obsolete(); 3576 ++obsolete_count; 3577 // With tracing we try not to "yack" too much. The position of 3578 // this trace assumes there are fewer obsolete methods than 3579 // EMCP methods. 3580 RC_TRACE(0x00000100, ("mark deleted %s(%s) as obsolete", 3581 old_method->name()->as_C_string(), 3582 old_method->signature()->as_C_string())); 3583 } 3584 assert((*emcp_method_count_p + obsolete_count) == _old_methods->length(), 3585 "sanity check"); 3586 RC_TRACE(0x00000100, ("EMCP_cnt=%d, obsolete_cnt=%d", *emcp_method_count_p, 3587 obsolete_count)); 3588 } 3589 3590 // This internal class transfers the native function registration from old methods 3591 // to new methods. It is designed to handle both the simple case of unchanged 3592 // native methods and the complex cases of native method prefixes being added and/or 3593 // removed. 3594 // It expects only to be used during the VM_RedefineClasses op (a safepoint). 3595 // 3596 // This class is used after the new methods have been installed in "the_class". 3597 // 3598 // So, for example, the following must be handled. Where 'm' is a method and 3599 // a number followed by an underscore is a prefix. 3600 // 3601 // Old Name New Name 3602 // Simple transfer to new method m -> m 3603 // Add prefix m -> 1_m 3604 // Remove prefix 1_m -> m 3605 // Simultaneous add of prefixes m -> 3_2_1_m 3606 // Simultaneous removal of prefixes 3_2_1_m -> m 3607 // Simultaneous add and remove 1_m -> 2_m 3608 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m 3609 // 3610 class TransferNativeFunctionRegistration { 3611 private: 3612 instanceKlassHandle the_class; 3613 int prefix_count; 3614 char** prefixes; 3615 3616 // Recursively search the binary tree of possibly prefixed method names. 3617 // Iteration could be used if all agents were well behaved. Full tree walk is 3618 // more resilent to agents not cleaning up intermediate methods. 3619 // Branch at each depth in the binary tree is: 3620 // (1) without the prefix. 3621 // (2) with the prefix. 3622 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...) 3623 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len, 3624 Symbol* signature) { 3625 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len); 3626 if (name_symbol != NULL) { 3627 Method* method = the_class()->lookup_method(name_symbol, signature); 3628 if (method != NULL) { 3629 // Even if prefixed, intermediate methods must exist. 3630 if (method->is_native()) { 3631 // Wahoo, we found a (possibly prefixed) version of the method, return it. 3632 return method; 3633 } 3634 if (depth < prefix_count) { 3635 // Try applying further prefixes (other than this one). 3636 method = search_prefix_name_space(depth+1, name_str, name_len, signature); 3637 if (method != NULL) { 3638 return method; // found 3639 } 3640 3641 // Try adding this prefix to the method name and see if it matches 3642 // another method name. 3643 char* prefix = prefixes[depth]; 3644 size_t prefix_len = strlen(prefix); 3645 size_t trial_len = name_len + prefix_len; 3646 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1); 3647 strcpy(trial_name_str, prefix); 3648 strcat(trial_name_str, name_str); 3649 method = search_prefix_name_space(depth+1, trial_name_str, trial_len, 3650 signature); 3651 if (method != NULL) { 3652 // If found along this branch, it was prefixed, mark as such 3653 method->set_is_prefixed_native(); 3654 return method; // found 3655 } 3656 } 3657 } 3658 } 3659 return NULL; // This whole branch bore nothing 3660 } 3661 3662 // Return the method name with old prefixes stripped away. 3663 char* method_name_without_prefixes(Method* method) { 3664 Symbol* name = method->name(); 3665 char* name_str = name->as_utf8(); 3666 3667 // Old prefixing may be defunct, strip prefixes, if any. 3668 for (int i = prefix_count-1; i >= 0; i--) { 3669 char* prefix = prefixes[i]; 3670 size_t prefix_len = strlen(prefix); 3671 if (strncmp(prefix, name_str, prefix_len) == 0) { 3672 name_str += prefix_len; 3673 } 3674 } 3675 return name_str; 3676 } 3677 3678 // Strip any prefixes off the old native method, then try to find a 3679 // (possibly prefixed) new native that matches it. 3680 Method* strip_and_search_for_new_native(Method* method) { 3681 ResourceMark rm; 3682 char* name_str = method_name_without_prefixes(method); 3683 return search_prefix_name_space(0, name_str, strlen(name_str), 3684 method->signature()); 3685 } 3686 3687 public: 3688 3689 // Construct a native method transfer processor for this class. 3690 TransferNativeFunctionRegistration(instanceKlassHandle _the_class) { 3691 assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); 3692 3693 the_class = _the_class; 3694 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count); 3695 } 3696 3697 // Attempt to transfer any of the old or deleted methods that are native 3698 void transfer_registrations(Method** old_methods, int methods_length) { 3699 for (int j = 0; j < methods_length; j++) { 3700 Method* old_method = old_methods[j]; 3701 3702 if (old_method->is_native() && old_method->has_native_function()) { 3703 Method* new_method = strip_and_search_for_new_native(old_method); 3704 if (new_method != NULL) { 3705 // Actually set the native function in the new method. 3706 // Redefine does not send events (except CFLH), certainly not this 3707 // behind the scenes re-registration. 3708 new_method->set_native_function(old_method->native_function(), 3709 !Method::native_bind_event_is_interesting); 3710 } 3711 } 3712 } 3713 } 3714 }; 3715 3716 // Don't lose the association between a native method and its JNI function. 3717 void VM_RedefineClasses::transfer_old_native_function_registrations(instanceKlassHandle the_class) { 3718 TransferNativeFunctionRegistration transfer(the_class); 3719 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length); 3720 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length); 3721 } 3722 3723 // Deoptimize all compiled code that depends on this class. 3724 // 3725 // If the can_redefine_classes capability is obtained in the onload 3726 // phase then the compiler has recorded all dependencies from startup. 3727 // In that case we need only deoptimize and throw away all compiled code 3728 // that depends on the class. 3729 // 3730 // If can_redefine_classes is obtained sometime after the onload 3731 // phase then the dependency information may be incomplete. In that case 3732 // the first call to RedefineClasses causes all compiled code to be 3733 // thrown away. As can_redefine_classes has been obtained then 3734 // all future compilations will record dependencies so second and 3735 // subsequent calls to RedefineClasses need only throw away code 3736 // that depends on the class. 3737 // 3738 void VM_RedefineClasses::flush_dependent_code(instanceKlassHandle k_h, TRAPS) { 3739 assert_locked_or_safepoint(Compile_lock); 3740 3741 // All dependencies have been recorded from startup or this is a second or 3742 // subsequent use of RedefineClasses 3743 if (JvmtiExport::all_dependencies_are_recorded()) { 3744 Universe::flush_evol_dependents_on(k_h); 3745 } else { 3746 CodeCache::mark_all_nmethods_for_deoptimization(); 3747 3748 ResourceMark rm(THREAD); 3749 DeoptimizationMarker dm; 3750 3751 // Deoptimize all activations depending on marked nmethods 3752 Deoptimization::deoptimize_dependents(); 3753 3754 // Make the dependent methods not entrant (in VM_Deoptimize they are made zombies) 3755 CodeCache::make_marked_nmethods_not_entrant(); 3756 3757 // From now on we know that the dependency information is complete 3758 JvmtiExport::set_all_dependencies_are_recorded(true); 3759 } 3760 } 3761 3762 void VM_RedefineClasses::compute_added_deleted_matching_methods() { 3763 Method* old_method; 3764 Method* new_method; 3765 3766 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 3767 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 3768 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length()); 3769 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 3770 3771 _matching_methods_length = 0; 3772 _deleted_methods_length = 0; 3773 _added_methods_length = 0; 3774 3775 int nj = 0; 3776 int oj = 0; 3777 while (true) { 3778 if (oj >= _old_methods->length()) { 3779 if (nj >= _new_methods->length()) { 3780 break; // we've looked at everything, done 3781 } 3782 // New method at the end 3783 new_method = _new_methods->at(nj); 3784 _added_methods[_added_methods_length++] = new_method; 3785 ++nj; 3786 } else if (nj >= _new_methods->length()) { 3787 // Old method, at the end, is deleted 3788 old_method = _old_methods->at(oj); 3789 _deleted_methods[_deleted_methods_length++] = old_method; 3790 ++oj; 3791 } else { 3792 old_method = _old_methods->at(oj); 3793 new_method = _new_methods->at(nj); 3794 if (old_method->name() == new_method->name()) { 3795 if (old_method->signature() == new_method->signature()) { 3796 _matching_old_methods[_matching_methods_length ] = old_method; 3797 _matching_new_methods[_matching_methods_length++] = new_method; 3798 ++nj; 3799 ++oj; 3800 } else { 3801 // added overloaded have already been moved to the end, 3802 // so this is a deleted overloaded method 3803 _deleted_methods[_deleted_methods_length++] = old_method; 3804 ++oj; 3805 } 3806 } else { // names don't match 3807 if (old_method->name()->fast_compare(new_method->name()) > 0) { 3808 // new method 3809 _added_methods[_added_methods_length++] = new_method; 3810 ++nj; 3811 } else { 3812 // deleted method 3813 _deleted_methods[_deleted_methods_length++] = old_method; 3814 ++oj; 3815 } 3816 } 3817 } 3818 } 3819 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity"); 3820 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity"); 3821 } 3822 3823 3824 void VM_RedefineClasses::swap_annotations(instanceKlassHandle the_class, 3825 instanceKlassHandle scratch_class) { 3826 // Swap annotation fields values 3827 Annotations* old_annotations = the_class->annotations(); 3828 the_class->set_annotations(scratch_class->annotations()); 3829 scratch_class->set_annotations(old_annotations); 3830 } 3831 3832 3833 // Install the redefinition of a class: 3834 // - house keeping (flushing breakpoints and caches, deoptimizing 3835 // dependent compiled code) 3836 // - replacing parts in the_class with parts from scratch_class 3837 // - adding a weak reference to track the obsolete but interesting 3838 // parts of the_class 3839 // - adjusting constant pool caches and vtables in other classes 3840 // that refer to methods in the_class. These adjustments use the 3841 // ClassLoaderDataGraph::classes_do() facility which only allows 3842 // a helper method to be specified. The interesting parameters 3843 // that we would like to pass to the helper method are saved in 3844 // static global fields in the VM operation. 3845 void VM_RedefineClasses::redefine_single_class(jclass the_jclass, 3846 Klass* scratch_class_oop, TRAPS) { 3847 3848 HandleMark hm(THREAD); // make sure handles from this call are freed 3849 RC_TIMER_START(_timer_rsc_phase1); 3850 3851 instanceKlassHandle scratch_class(scratch_class_oop); 3852 3853 oop the_class_mirror = JNIHandles::resolve_non_null(the_jclass); 3854 Klass* the_class_oop = java_lang_Class::as_Klass(the_class_mirror); 3855 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop); 3856 3857 // Remove all breakpoints in methods of this class 3858 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints(); 3859 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class_oop); 3860 3861 // Deoptimize all compiled code that depends on this class 3862 flush_dependent_code(the_class, THREAD); 3863 3864 _old_methods = the_class->methods(); 3865 _new_methods = scratch_class->methods(); 3866 _the_class_oop = the_class_oop; 3867 compute_added_deleted_matching_methods(); 3868 update_jmethod_ids(); 3869 3870 // Attach new constant pool to the original klass. The original 3871 // klass still refers to the old constant pool (for now). 3872 scratch_class->constants()->set_pool_holder(the_class()); 3873 3874 #if 0 3875 // In theory, with constant pool merging in place we should be able 3876 // to save space by using the new, merged constant pool in place of 3877 // the old constant pool(s). By "pool(s)" I mean the constant pool in 3878 // the klass version we are replacing now and any constant pool(s) in 3879 // previous versions of klass. Nice theory, doesn't work in practice. 3880 // When this code is enabled, even simple programs throw NullPointer 3881 // exceptions. I'm guessing that this is caused by some constant pool 3882 // cache difference between the new, merged constant pool and the 3883 // constant pool that was just being used by the klass. I'm keeping 3884 // this code around to archive the idea, but the code has to remain 3885 // disabled for now. 3886 3887 // Attach each old method to the new constant pool. This can be 3888 // done here since we are past the bytecode verification and 3889 // constant pool optimization phases. 3890 for (int i = _old_methods->length() - 1; i >= 0; i--) { 3891 Method* method = _old_methods->at(i); 3892 method->set_constants(scratch_class->constants()); 3893 } 3894 3895 { 3896 // walk all previous versions of the klass 3897 InstanceKlass *ik = (InstanceKlass *)the_class(); 3898 PreviousVersionWalker pvw(ik); 3899 instanceKlassHandle ikh; 3900 do { 3901 ikh = pvw.next_previous_version(); 3902 if (!ikh.is_null()) { 3903 ik = ikh(); 3904 3905 // attach previous version of klass to the new constant pool 3906 ik->set_constants(scratch_class->constants()); 3907 3908 // Attach each method in the previous version of klass to the 3909 // new constant pool 3910 Array<Method*>* prev_methods = ik->methods(); 3911 for (int i = prev_methods->length() - 1; i >= 0; i--) { 3912 Method* method = prev_methods->at(i); 3913 method->set_constants(scratch_class->constants()); 3914 } 3915 } 3916 } while (!ikh.is_null()); 3917 } 3918 #endif 3919 3920 // Replace methods and constantpool 3921 the_class->set_methods(_new_methods); 3922 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods, 3923 // and to be able to undo operation easily. 3924 3925 ConstantPool* old_constants = the_class->constants(); 3926 the_class->set_constants(scratch_class->constants()); 3927 scratch_class->set_constants(old_constants); // See the previous comment. 3928 #if 0 3929 // We are swapping the guts of "the new class" with the guts of "the 3930 // class". Since the old constant pool has just been attached to "the 3931 // new class", it seems logical to set the pool holder in the old 3932 // constant pool also. However, doing this will change the observable 3933 // class hierarchy for any old methods that are still executing. A 3934 // method can query the identity of its "holder" and this query uses 3935 // the method's constant pool link to find the holder. The change in 3936 // holding class from "the class" to "the new class" can confuse 3937 // things. 3938 // 3939 // Setting the old constant pool's holder will also cause 3940 // verification done during vtable initialization below to fail. 3941 // During vtable initialization, the vtable's class is verified to be 3942 // a subtype of the method's holder. The vtable's class is "the 3943 // class" and the method's holder is gotten from the constant pool 3944 // link in the method itself. For "the class"'s directly implemented 3945 // methods, the method holder is "the class" itself (as gotten from 3946 // the new constant pool). The check works fine in this case. The 3947 // check also works fine for methods inherited from super classes. 3948 // 3949 // Miranda methods are a little more complicated. A miranda method is 3950 // provided by an interface when the class implementing the interface 3951 // does not provide its own method. These interfaces are implemented 3952 // internally as an InstanceKlass. These special instanceKlasses 3953 // share the constant pool of the class that "implements" the 3954 // interface. By sharing the constant pool, the method holder of a 3955 // miranda method is the class that "implements" the interface. In a 3956 // non-redefine situation, the subtype check works fine. However, if 3957 // the old constant pool's pool holder is modified, then the check 3958 // fails because there is no class hierarchy relationship between the 3959 // vtable's class and "the new class". 3960 3961 old_constants->set_pool_holder(scratch_class()); 3962 #endif 3963 3964 // track which methods are EMCP for add_previous_version() call below 3965 BitMap emcp_methods(_old_methods->length()); 3966 int emcp_method_count = 0; 3967 emcp_methods.clear(); // clears 0..(length() - 1) 3968 check_methods_and_mark_as_obsolete(&emcp_methods, &emcp_method_count); 3969 transfer_old_native_function_registrations(the_class); 3970 3971 // The class file bytes from before any retransformable agents mucked 3972 // with them was cached on the scratch class, move to the_class. 3973 // Note: we still want to do this if nothing needed caching since it 3974 // should get cleared in the_class too. 3975 if (the_class->get_cached_class_file_bytes() == 0) { 3976 // the_class doesn't have a cache yet so copy it 3977 the_class->set_cached_class_file(scratch_class->get_cached_class_file()); 3978 } 3979 else if (scratch_class->get_cached_class_file_bytes() != 3980 the_class->get_cached_class_file_bytes()) { 3981 // The same class can be present twice in the scratch classes list or there 3982 // are multiple concurrent RetransformClasses calls on different threads. 3983 // In such cases we have to deallocate scratch_class cached_class_file_bytes. 3984 os::free(scratch_class->get_cached_class_file_bytes()); 3985 } 3986 3987 // NULL out in scratch class to not delete twice. The class to be redefined 3988 // always owns these bytes. 3989 scratch_class->set_cached_class_file(NULL); 3990 3991 // Replace inner_classes 3992 Array<u2>* old_inner_classes = the_class->inner_classes(); 3993 the_class->set_inner_classes(scratch_class->inner_classes()); 3994 scratch_class->set_inner_classes(old_inner_classes); 3995 3996 // Initialize the vtable and interface table after 3997 // methods have been rewritten 3998 { 3999 ResourceMark rm(THREAD); 4000 // no exception should happen here since we explicitly 4001 // do not check loader constraints. 4002 // compare_and_normalize_class_versions has already checked: 4003 // - classloaders unchanged, signatures unchanged 4004 // - all instanceKlasses for redefined classes reused & contents updated 4005 the_class->vtable()->initialize_vtable(false, THREAD); 4006 the_class->itable()->initialize_itable(false, THREAD); 4007 assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())), "redefine exception"); 4008 } 4009 4010 // Leave arrays of jmethodIDs and itable index cache unchanged 4011 4012 // Copy the "source file name" attribute from new class version 4013 the_class->set_source_file_name_index( 4014 scratch_class->source_file_name_index()); 4015 4016 // Copy the "source debug extension" attribute from new class version 4017 the_class->set_source_debug_extension( 4018 scratch_class->source_debug_extension(), 4019 scratch_class->source_debug_extension() == NULL ? 0 : 4020 (int)strlen(scratch_class->source_debug_extension())); 4021 4022 // Use of javac -g could be different in the old and the new 4023 if (scratch_class->access_flags().has_localvariable_table() != 4024 the_class->access_flags().has_localvariable_table()) { 4025 4026 AccessFlags flags = the_class->access_flags(); 4027 if (scratch_class->access_flags().has_localvariable_table()) { 4028 flags.set_has_localvariable_table(); 4029 } else { 4030 flags.clear_has_localvariable_table(); 4031 } 4032 the_class->set_access_flags(flags); 4033 } 4034 4035 swap_annotations(the_class, scratch_class); 4036 4037 // Replace minor version number of class file 4038 u2 old_minor_version = the_class->minor_version(); 4039 the_class->set_minor_version(scratch_class->minor_version()); 4040 scratch_class->set_minor_version(old_minor_version); 4041 4042 // Replace major version number of class file 4043 u2 old_major_version = the_class->major_version(); 4044 the_class->set_major_version(scratch_class->major_version()); 4045 scratch_class->set_major_version(old_major_version); 4046 4047 // Replace CP indexes for class and name+type of enclosing method 4048 u2 old_class_idx = the_class->enclosing_method_class_index(); 4049 u2 old_method_idx = the_class->enclosing_method_method_index(); 4050 the_class->set_enclosing_method_indices( 4051 scratch_class->enclosing_method_class_index(), 4052 scratch_class->enclosing_method_method_index()); 4053 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx); 4054 4055 // keep track of previous versions of this class 4056 the_class->add_previous_version(scratch_class, &emcp_methods, 4057 emcp_method_count); 4058 4059 RC_TIMER_STOP(_timer_rsc_phase1); 4060 RC_TIMER_START(_timer_rsc_phase2); 4061 4062 // Adjust constantpool caches and vtables for all classes 4063 // that reference methods of the evolved class. 4064 AdjustCpoolCacheAndVtable adjust_cpool_cache_and_vtable(THREAD); 4065 ClassLoaderDataGraph::classes_do(&adjust_cpool_cache_and_vtable); 4066 4067 // JSR-292 support 4068 MemberNameTable* mnt = the_class->member_names(); 4069 if (mnt != NULL) { 4070 bool trace_name_printed = false; 4071 mnt->adjust_method_entries(the_class(), &trace_name_printed); 4072 } 4073 4074 // Fix Resolution Error table also to remove old constant pools 4075 SystemDictionary::delete_resolution_error(old_constants); 4076 4077 if (the_class->oop_map_cache() != NULL) { 4078 // Flush references to any obsolete methods from the oop map cache 4079 // so that obsolete methods are not pinned. 4080 the_class->oop_map_cache()->flush_obsolete_entries(); 4081 } 4082 4083 // increment the classRedefinedCount field in the_class and in any 4084 // direct and indirect subclasses of the_class 4085 increment_class_counter((InstanceKlass *)the_class(), THREAD); 4086 4087 // RC_TRACE macro has an embedded ResourceMark 4088 RC_TRACE_WITH_THREAD(0x00000001, THREAD, 4089 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)", 4090 the_class->external_name(), 4091 java_lang_Class::classRedefinedCount(the_class_mirror), 4092 os::available_memory() >> 10)); 4093 4094 RC_TIMER_STOP(_timer_rsc_phase2); 4095 } // end redefine_single_class() 4096 4097 4098 // Increment the classRedefinedCount field in the specific InstanceKlass 4099 // and in all direct and indirect subclasses. 4100 void VM_RedefineClasses::increment_class_counter(InstanceKlass *ik, TRAPS) { 4101 oop class_mirror = ik->java_mirror(); 4102 Klass* class_oop = java_lang_Class::as_Klass(class_mirror); 4103 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1; 4104 java_lang_Class::set_classRedefinedCount(class_mirror, new_count); 4105 4106 if (class_oop != _the_class_oop) { 4107 // _the_class_oop count is printed at end of redefine_single_class() 4108 RC_TRACE_WITH_THREAD(0x00000008, THREAD, 4109 ("updated count in subclass=%s to %d", ik->external_name(), new_count)); 4110 } 4111 4112 for (Klass *subk = ik->subklass(); subk != NULL; 4113 subk = subk->next_sibling()) { 4114 if (subk->oop_is_instance()) { 4115 // Only update instanceKlasses 4116 InstanceKlass *subik = (InstanceKlass*)subk; 4117 // recursively do subclasses of the current subclass 4118 increment_class_counter(subik, THREAD); 4119 } 4120 } 4121 } 4122 4123 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) { 4124 bool no_old_methods = true; // be optimistic 4125 4126 // Both array and instance classes have vtables. 4127 // a vtable should never contain old or obsolete methods 4128 ResourceMark rm(_thread); 4129 if (k->vtable_length() > 0 && 4130 !k->vtable()->check_no_old_or_obsolete_entries()) { 4131 if (RC_TRACE_ENABLED(0x00004000)) { 4132 RC_TRACE_WITH_THREAD(0x00004000, _thread, 4133 ("klassVtable::check_no_old_or_obsolete_entries failure" 4134 " -- OLD or OBSOLETE method found -- class: %s", 4135 k->signature_name())); 4136 k->vtable()->dump_vtable(); 4137 } 4138 no_old_methods = false; 4139 } 4140 4141 if (k->oop_is_instance()) { 4142 HandleMark hm(_thread); 4143 InstanceKlass *ik = InstanceKlass::cast(k); 4144 4145 // an itable should never contain old or obsolete methods 4146 if (ik->itable_length() > 0 && 4147 !ik->itable()->check_no_old_or_obsolete_entries()) { 4148 if (RC_TRACE_ENABLED(0x00004000)) { 4149 RC_TRACE_WITH_THREAD(0x00004000, _thread, 4150 ("klassItable::check_no_old_or_obsolete_entries failure" 4151 " -- OLD or OBSOLETE method found -- class: %s", 4152 ik->signature_name())); 4153 ik->itable()->dump_itable(); 4154 } 4155 no_old_methods = false; 4156 } 4157 4158 // the constant pool cache should never contain non-deleted old or obsolete methods 4159 if (ik->constants() != NULL && 4160 ik->constants()->cache() != NULL && 4161 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) { 4162 if (RC_TRACE_ENABLED(0x00004000)) { 4163 RC_TRACE_WITH_THREAD(0x00004000, _thread, 4164 ("cp-cache::check_no_old_or_obsolete_entries failure" 4165 " -- OLD or OBSOLETE method found -- class: %s", 4166 ik->signature_name())); 4167 ik->constants()->cache()->dump_cache(); 4168 } 4169 no_old_methods = false; 4170 } 4171 } 4172 4173 // print and fail guarantee if old methods are found. 4174 if (!no_old_methods) { 4175 if (RC_TRACE_ENABLED(0x00004000)) { 4176 dump_methods(); 4177 } else { 4178 tty->print_cr("INFO: use the '-XX:TraceRedefineClasses=16384' option " 4179 "to see more info about the following guarantee() failure."); 4180 } 4181 guarantee(false, "OLD and/or OBSOLETE method(s) found"); 4182 } 4183 } 4184 4185 4186 void VM_RedefineClasses::dump_methods() { 4187 int j; 4188 RC_TRACE(0x00004000, ("_old_methods --")); 4189 for (j = 0; j < _old_methods->length(); ++j) { 4190 Method* m = _old_methods->at(j); 4191 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index())); 4192 m->access_flags().print_on(tty); 4193 tty->print(" -- "); 4194 m->print_name(tty); 4195 tty->cr(); 4196 } 4197 RC_TRACE(0x00004000, ("_new_methods --")); 4198 for (j = 0; j < _new_methods->length(); ++j) { 4199 Method* m = _new_methods->at(j); 4200 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index())); 4201 m->access_flags().print_on(tty); 4202 tty->print(" -- "); 4203 m->print_name(tty); 4204 tty->cr(); 4205 } 4206 RC_TRACE(0x00004000, ("_matching_(old/new)_methods --")); 4207 for (j = 0; j < _matching_methods_length; ++j) { 4208 Method* m = _matching_old_methods[j]; 4209 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index())); 4210 m->access_flags().print_on(tty); 4211 tty->print(" -- "); 4212 m->print_name(tty); 4213 tty->cr(); 4214 m = _matching_new_methods[j]; 4215 RC_TRACE_NO_CR(0x00004000, (" (%5d) ", m->vtable_index())); 4216 m->access_flags().print_on(tty); 4217 tty->cr(); 4218 } 4219 RC_TRACE(0x00004000, ("_deleted_methods --")); 4220 for (j = 0; j < _deleted_methods_length; ++j) { 4221 Method* m = _deleted_methods[j]; 4222 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index())); 4223 m->access_flags().print_on(tty); 4224 tty->print(" -- "); 4225 m->print_name(tty); 4226 tty->cr(); 4227 } 4228 RC_TRACE(0x00004000, ("_added_methods --")); 4229 for (j = 0; j < _added_methods_length; ++j) { 4230 Method* m = _added_methods[j]; 4231 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index())); 4232 m->access_flags().print_on(tty); 4233 tty->print(" -- "); 4234 m->print_name(tty); 4235 tty->cr(); 4236 } 4237 }