1 /* 2 * Copyright (c) 2003, 2017, 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 #include "utilities/events.hpp" 46 47 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC 48 49 Array<Method*>* VM_RedefineClasses::_old_methods = NULL; 50 Array<Method*>* VM_RedefineClasses::_new_methods = NULL; 51 Method** VM_RedefineClasses::_matching_old_methods = NULL; 52 Method** VM_RedefineClasses::_matching_new_methods = NULL; 53 Method** VM_RedefineClasses::_deleted_methods = NULL; 54 Method** VM_RedefineClasses::_added_methods = NULL; 55 int VM_RedefineClasses::_matching_methods_length = 0; 56 int VM_RedefineClasses::_deleted_methods_length = 0; 57 int VM_RedefineClasses::_added_methods_length = 0; 58 Klass* VM_RedefineClasses::_the_class_oop = NULL; 59 60 61 VM_RedefineClasses::VM_RedefineClasses(jint class_count, 62 const jvmtiClassDefinition *class_defs, 63 JvmtiClassLoadKind class_load_kind) { 64 _class_count = class_count; 65 _class_defs = class_defs; 66 _class_load_kind = class_load_kind; 67 _res = JVMTI_ERROR_NONE; 68 } 69 70 static inline InstanceKlass* get_ik(jclass def) { 71 oop mirror = JNIHandles::resolve_non_null(def); 72 return InstanceKlass::cast(java_lang_Class::as_Klass(mirror)); 73 } 74 75 bool VM_RedefineClasses::doit_prologue() { 76 if (_class_count == 0) { 77 _res = JVMTI_ERROR_NONE; 78 return false; 79 } 80 if (_class_defs == NULL) { 81 _res = JVMTI_ERROR_NULL_POINTER; 82 return false; 83 } 84 for (int i = 0; i < _class_count; i++) { 85 if (_class_defs[i].klass == NULL) { 86 _res = JVMTI_ERROR_INVALID_CLASS; 87 return false; 88 } 89 if (_class_defs[i].class_byte_count == 0) { 90 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT; 91 return false; 92 } 93 if (_class_defs[i].class_bytes == NULL) { 94 _res = JVMTI_ERROR_NULL_POINTER; 95 return false; 96 } 97 } 98 99 // Start timer after all the sanity checks; not quite accurate, but 100 // better than adding a bunch of stop() calls. 101 RC_TIMER_START(_timer_vm_op_prologue); 102 103 // We first load new class versions in the prologue, because somewhere down the 104 // call chain it is required that the current thread is a Java thread. 105 _res = load_new_class_versions(Thread::current()); 106 if (_res != JVMTI_ERROR_NONE) { 107 // free any successfully created classes, since none are redefined 108 for (int i = 0; i < _class_count; i++) { 109 if (_scratch_classes[i] != NULL) { 110 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data(); 111 // Free the memory for this class at class unloading time. Not before 112 // because CMS might think this is still live. 113 InstanceKlass* ik = get_ik(_class_defs[i].klass); 114 if (ik->get_cached_class_file() == ((InstanceKlass*)_scratch_classes[i])->get_cached_class_file()) { 115 // Don't double-free cached_class_file copied from the original class if error. 116 ((InstanceKlass*)_scratch_classes[i])->set_cached_class_file(NULL); 117 } 118 cld->add_to_deallocate_list((InstanceKlass*)_scratch_classes[i]); 119 } 120 } 121 // Free os::malloc allocated memory in load_new_class_version. 122 os::free(_scratch_classes); 123 RC_TIMER_STOP(_timer_vm_op_prologue); 124 return false; 125 } 126 127 RC_TIMER_STOP(_timer_vm_op_prologue); 128 return true; 129 } 130 131 void VM_RedefineClasses::doit() { 132 Thread *thread = Thread::current(); 133 134 if (UseSharedSpaces) { 135 // Sharing is enabled so we remap the shared readonly space to 136 // shared readwrite, private just in case we need to redefine 137 // a shared class. We do the remap during the doit() phase of 138 // the safepoint to be safer. 139 if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) { 140 RC_TRACE_WITH_THREAD(0x00000001, thread, 141 ("failed to remap shared readonly space to readwrite, private")); 142 _res = JVMTI_ERROR_INTERNAL; 143 return; 144 } 145 } 146 147 // Mark methods seen on stack and everywhere else so old methods are not 148 // cleaned up if they're on the stack. 149 MetadataOnStackMark md_on_stack(true); 150 HandleMark hm(thread); // make sure any handles created are deleted 151 // before the stack walk again. 152 153 for (int i = 0; i < _class_count; i++) { 154 redefine_single_class(_class_defs[i].klass, _scratch_classes[i], thread); 155 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data(); 156 // Free the memory for this class at class unloading time. Not before 157 // because CMS might think this is still live. 158 cld->add_to_deallocate_list((InstanceKlass*)_scratch_classes[i]); 159 _scratch_classes[i] = NULL; 160 } 161 162 // Disable any dependent concurrent compilations 163 SystemDictionary::notice_modification(); 164 165 // Set flag indicating that some invariants are no longer true. 166 // See jvmtiExport.hpp for detailed explanation. 167 JvmtiExport::set_has_redefined_a_class(); 168 169 // check_class() is optionally called for product bits, but is 170 // always called for non-product bits. 171 #ifdef PRODUCT 172 if (RC_TRACE_ENABLED(0x00004000)) { 173 #endif 174 RC_TRACE_WITH_THREAD(0x00004000, thread, ("calling check_class")); 175 CheckClass check_class(thread); 176 ClassLoaderDataGraph::classes_do(&check_class); 177 #ifdef PRODUCT 178 } 179 #endif 180 } 181 182 void VM_RedefineClasses::doit_epilogue() { 183 // Free os::malloc allocated memory. 184 os::free(_scratch_classes); 185 186 // Reset the_class_oop to null for error printing. 187 _the_class_oop = NULL; 188 189 if (RC_TRACE_ENABLED(0x00000004)) { 190 // Used to have separate timers for "doit" and "all", but the timer 191 // overhead skewed the measurements. 192 jlong doit_time = _timer_rsc_phase1.milliseconds() + 193 _timer_rsc_phase2.milliseconds(); 194 jlong all_time = _timer_vm_op_prologue.milliseconds() + doit_time; 195 196 RC_TRACE(0x00000004, ("vm_op: all=" UINT64_FORMAT 197 " prologue=" UINT64_FORMAT " doit=" UINT64_FORMAT, all_time, 198 _timer_vm_op_prologue.milliseconds(), doit_time)); 199 RC_TRACE(0x00000004, 200 ("redefine_single_class: phase1=" UINT64_FORMAT " phase2=" UINT64_FORMAT, 201 _timer_rsc_phase1.milliseconds(), _timer_rsc_phase2.milliseconds())); 202 } 203 } 204 205 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) { 206 // classes for primitives cannot be redefined 207 if (java_lang_Class::is_primitive(klass_mirror)) { 208 return false; 209 } 210 Klass* the_class_oop = java_lang_Class::as_Klass(klass_mirror); 211 // classes for arrays cannot be redefined 212 if (the_class_oop == NULL || !the_class_oop->oop_is_instance()) { 213 return false; 214 } 215 return true; 216 } 217 218 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p 219 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For 220 // direct CP entries, there is just the current entry to append. For 221 // indirect and double-indirect CP entries, there are zero or more 222 // referenced CP entries along with the current entry to append. 223 // Indirect and double-indirect CP entries are handled by recursive 224 // calls to append_entry() as needed. The referenced CP entries are 225 // always appended to *merge_cp_p before the referee CP entry. These 226 // referenced CP entries may already exist in *merge_cp_p in which case 227 // there is nothing extra to append and only the current entry is 228 // appended. 229 void VM_RedefineClasses::append_entry(constantPoolHandle scratch_cp, 230 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, 231 TRAPS) { 232 233 // append is different depending on entry tag type 234 switch (scratch_cp->tag_at(scratch_i).value()) { 235 236 // The old verifier is implemented outside the VM. It loads classes, 237 // but does not resolve constant pool entries directly so we never 238 // see Class entries here with the old verifier. Similarly the old 239 // verifier does not like Class entries in the input constant pool. 240 // The split-verifier is implemented in the VM so it can optionally 241 // and directly resolve constant pool entries to load classes. The 242 // split-verifier can accept either Class entries or UnresolvedClass 243 // entries in the input constant pool. We revert the appended copy 244 // back to UnresolvedClass so that either verifier will be happy 245 // with the constant pool entry. 246 case JVM_CONSTANT_Class: 247 { 248 // revert the copy to JVM_CONSTANT_UnresolvedClass 249 (*merge_cp_p)->unresolved_klass_at_put(*merge_cp_length_p, 250 scratch_cp->klass_name_at(scratch_i)); 251 252 if (scratch_i != *merge_cp_length_p) { 253 // The new entry in *merge_cp_p is at a different index than 254 // the new entry in scratch_cp so we need to map the index values. 255 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 256 } 257 (*merge_cp_length_p)++; 258 } break; 259 260 // these are direct CP entries so they can be directly appended, 261 // but double and long take two constant pool entries 262 case JVM_CONSTANT_Double: // fall through 263 case JVM_CONSTANT_Long: 264 { 265 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p, 266 THREAD); 267 268 if (scratch_i != *merge_cp_length_p) { 269 // The new entry in *merge_cp_p is at a different index than 270 // the new entry in scratch_cp so we need to map the index values. 271 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 272 } 273 (*merge_cp_length_p) += 2; 274 } break; 275 276 // these are direct CP entries so they can be directly appended 277 case JVM_CONSTANT_Float: // fall through 278 case JVM_CONSTANT_Integer: // fall through 279 case JVM_CONSTANT_Utf8: // fall through 280 281 // This was an indirect CP entry, but it has been changed into 282 // Symbol*s so this entry can be directly appended. 283 case JVM_CONSTANT_String: // fall through 284 285 // These were indirect CP entries, but they have been changed into 286 // Symbol*s so these entries can be directly appended. 287 case JVM_CONSTANT_UnresolvedClass: // fall through 288 { 289 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p, 290 THREAD); 291 292 if (scratch_i != *merge_cp_length_p) { 293 // The new entry in *merge_cp_p is at a different index than 294 // the new entry in scratch_cp so we need to map the index values. 295 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 296 } 297 (*merge_cp_length_p)++; 298 } break; 299 300 // this is an indirect CP entry so it needs special handling 301 case JVM_CONSTANT_NameAndType: 302 { 303 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i); 304 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p, 305 merge_cp_length_p, THREAD); 306 307 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i); 308 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i, 309 merge_cp_p, merge_cp_length_p, 310 THREAD); 311 312 // If the referenced entries already exist in *merge_cp_p, then 313 // both new_name_ref_i and new_signature_ref_i will both be 0. 314 // In that case, all we are appending is the current entry. 315 if (new_name_ref_i != name_ref_i) { 316 RC_TRACE(0x00080000, 317 ("NameAndType entry@%d name_ref_index change: %d to %d", 318 *merge_cp_length_p, name_ref_i, new_name_ref_i)); 319 } 320 if (new_signature_ref_i != signature_ref_i) { 321 RC_TRACE(0x00080000, 322 ("NameAndType entry@%d signature_ref_index change: %d to %d", 323 *merge_cp_length_p, signature_ref_i, new_signature_ref_i)); 324 } 325 326 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p, 327 new_name_ref_i, new_signature_ref_i); 328 if (scratch_i != *merge_cp_length_p) { 329 // The new entry in *merge_cp_p is at a different index than 330 // the new entry in scratch_cp so we need to map the index values. 331 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 332 } 333 (*merge_cp_length_p)++; 334 } break; 335 336 // this is a double-indirect CP entry so it needs special handling 337 case JVM_CONSTANT_Fieldref: // fall through 338 case JVM_CONSTANT_InterfaceMethodref: // fall through 339 case JVM_CONSTANT_Methodref: 340 { 341 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i); 342 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i, 343 merge_cp_p, merge_cp_length_p, THREAD); 344 345 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i); 346 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i, 347 merge_cp_p, merge_cp_length_p, THREAD); 348 349 const char *entry_name = NULL; 350 switch (scratch_cp->tag_at(scratch_i).value()) { 351 case JVM_CONSTANT_Fieldref: 352 entry_name = "Fieldref"; 353 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i, 354 new_name_and_type_ref_i); 355 break; 356 case JVM_CONSTANT_InterfaceMethodref: 357 entry_name = "IFMethodref"; 358 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p, 359 new_klass_ref_i, new_name_and_type_ref_i); 360 break; 361 case JVM_CONSTANT_Methodref: 362 entry_name = "Methodref"; 363 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i, 364 new_name_and_type_ref_i); 365 break; 366 default: 367 guarantee(false, "bad switch"); 368 break; 369 } 370 371 if (klass_ref_i != new_klass_ref_i) { 372 RC_TRACE(0x00080000, ("%s entry@%d class_index changed: %d to %d", 373 entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i)); 374 } 375 if (name_and_type_ref_i != new_name_and_type_ref_i) { 376 RC_TRACE(0x00080000, 377 ("%s entry@%d name_and_type_index changed: %d to %d", 378 entry_name, *merge_cp_length_p, name_and_type_ref_i, 379 new_name_and_type_ref_i)); 380 } 381 382 if (scratch_i != *merge_cp_length_p) { 383 // The new entry in *merge_cp_p is at a different index than 384 // the new entry in scratch_cp so we need to map the index values. 385 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 386 } 387 (*merge_cp_length_p)++; 388 } break; 389 390 // this is an indirect CP entry so it needs special handling 391 case JVM_CONSTANT_MethodType: 392 { 393 int ref_i = scratch_cp->method_type_index_at(scratch_i); 394 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p, 395 merge_cp_length_p, THREAD); 396 if (new_ref_i != ref_i) { 397 RC_TRACE(0x00080000, 398 ("MethodType entry@%d ref_index change: %d to %d", 399 *merge_cp_length_p, ref_i, new_ref_i)); 400 } 401 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i); 402 if (scratch_i != *merge_cp_length_p) { 403 // The new entry in *merge_cp_p is at a different index than 404 // the new entry in scratch_cp so we need to map the index values. 405 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 406 } 407 (*merge_cp_length_p)++; 408 } break; 409 410 // this is an indirect CP entry so it needs special handling 411 case JVM_CONSTANT_MethodHandle: 412 { 413 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i); 414 int ref_i = scratch_cp->method_handle_index_at(scratch_i); 415 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p, 416 merge_cp_length_p, THREAD); 417 if (new_ref_i != ref_i) { 418 RC_TRACE(0x00080000, 419 ("MethodHandle entry@%d ref_index change: %d to %d", 420 *merge_cp_length_p, ref_i, new_ref_i)); 421 } 422 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i); 423 if (scratch_i != *merge_cp_length_p) { 424 // The new entry in *merge_cp_p is at a different index than 425 // the new entry in scratch_cp so we need to map the index values. 426 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 427 } 428 (*merge_cp_length_p)++; 429 } break; 430 431 // this is an indirect CP entry so it needs special handling 432 case JVM_CONSTANT_InvokeDynamic: 433 { 434 // Index of the bootstrap specifier in the operands array 435 int old_bs_i = scratch_cp->invoke_dynamic_bootstrap_specifier_index(scratch_i); 436 int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p, 437 merge_cp_length_p, THREAD); 438 // The bootstrap method NameAndType_info index 439 int old_ref_i = scratch_cp->invoke_dynamic_name_and_type_ref_index_at(scratch_i); 440 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p, 441 merge_cp_length_p, THREAD); 442 if (new_bs_i != old_bs_i) { 443 RC_TRACE(0x00080000, 444 ("InvokeDynamic entry@%d bootstrap_method_attr_index change: %d to %d", 445 *merge_cp_length_p, old_bs_i, new_bs_i)); 446 } 447 if (new_ref_i != old_ref_i) { 448 RC_TRACE(0x00080000, 449 ("InvokeDynamic entry@%d name_and_type_index change: %d to %d", 450 *merge_cp_length_p, old_ref_i, new_ref_i)); 451 } 452 453 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i); 454 if (scratch_i != *merge_cp_length_p) { 455 // The new entry in *merge_cp_p is at a different index than 456 // the new entry in scratch_cp so we need to map the index values. 457 map_index(scratch_cp, scratch_i, *merge_cp_length_p); 458 } 459 (*merge_cp_length_p)++; 460 } break; 461 462 // At this stage, Class or UnresolvedClass could be here, but not 463 // ClassIndex 464 case JVM_CONSTANT_ClassIndex: // fall through 465 466 // Invalid is used as the tag for the second constant pool entry 467 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should 468 // not be seen by itself. 469 case JVM_CONSTANT_Invalid: // fall through 470 471 // At this stage, String could be here, but not StringIndex 472 case JVM_CONSTANT_StringIndex: // fall through 473 474 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be 475 // here 476 case JVM_CONSTANT_UnresolvedClassInError: // fall through 477 478 default: 479 { 480 // leave a breadcrumb 481 jbyte bad_value = scratch_cp->tag_at(scratch_i).value(); 482 ShouldNotReachHere(); 483 } break; 484 } // end switch tag value 485 } // end append_entry() 486 487 488 int VM_RedefineClasses::find_or_append_indirect_entry(constantPoolHandle scratch_cp, 489 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) { 490 491 int new_ref_i = ref_i; 492 bool match = (ref_i < *merge_cp_length_p) && 493 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i, THREAD); 494 495 if (!match) { 496 // forward reference in *merge_cp_p or not a direct match 497 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p, THREAD); 498 if (found_i != 0) { 499 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree"); 500 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry. 501 new_ref_i = found_i; 502 map_index(scratch_cp, ref_i, found_i); 503 } else { 504 // no match found so we have to append this entry to *merge_cp_p 505 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p, THREAD); 506 // The above call to append_entry() can only append one entry 507 // so the post call query of *merge_cp_length_p is only for 508 // the sake of consistency. 509 new_ref_i = *merge_cp_length_p - 1; 510 } 511 } 512 513 return new_ref_i; 514 } // end find_or_append_indirect_entry() 515 516 517 // Append a bootstrap specifier into the merge_cp operands that is semantically equal 518 // to the scratch_cp operands bootstrap specifier passed by the old_bs_i index. 519 // Recursively append new merge_cp entries referenced by the new bootstrap specifier. 520 void VM_RedefineClasses::append_operand(constantPoolHandle scratch_cp, int old_bs_i, 521 constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) { 522 523 int old_ref_i = scratch_cp->operand_bootstrap_method_ref_index_at(old_bs_i); 524 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p, 525 merge_cp_length_p, THREAD); 526 if (new_ref_i != old_ref_i) { 527 RC_TRACE(0x00080000, 528 ("operands entry@%d bootstrap method ref_index change: %d to %d", 529 _operands_cur_length, old_ref_i, new_ref_i)); 530 } 531 532 Array<u2>* merge_ops = (*merge_cp_p)->operands(); 533 int new_bs_i = _operands_cur_length; 534 // We have _operands_cur_length == 0 when the merge_cp operands is empty yet. 535 // However, the operand_offset_at(0) was set in the extend_operands() call. 536 int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0) 537 : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1); 538 int argc = scratch_cp->operand_argument_count_at(old_bs_i); 539 540 ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base); 541 merge_ops->at_put(new_base++, new_ref_i); 542 merge_ops->at_put(new_base++, argc); 543 544 for (int i = 0; i < argc; i++) { 545 int old_arg_ref_i = scratch_cp->operand_argument_index_at(old_bs_i, i); 546 int new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p, 547 merge_cp_length_p, THREAD); 548 merge_ops->at_put(new_base++, new_arg_ref_i); 549 if (new_arg_ref_i != old_arg_ref_i) { 550 RC_TRACE(0x00080000, 551 ("operands entry@%d bootstrap method argument ref_index change: %d to %d", 552 _operands_cur_length, old_arg_ref_i, new_arg_ref_i)); 553 } 554 } 555 if (old_bs_i != _operands_cur_length) { 556 // The bootstrap specifier in *merge_cp_p is at a different index than 557 // that in scratch_cp so we need to map the index values. 558 map_operand_index(old_bs_i, new_bs_i); 559 } 560 _operands_cur_length++; 561 } // end append_operand() 562 563 564 int VM_RedefineClasses::find_or_append_operand(constantPoolHandle scratch_cp, 565 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) { 566 567 int new_bs_i = old_bs_i; // bootstrap specifier index 568 bool match = (old_bs_i < _operands_cur_length) && 569 scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i, THREAD); 570 571 if (!match) { 572 // forward reference in *merge_cp_p or not a direct match 573 int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p, 574 _operands_cur_length, THREAD); 575 if (found_i != -1) { 576 guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree"); 577 // found a matching operand somewhere else in *merge_cp_p so just need a mapping 578 new_bs_i = found_i; 579 map_operand_index(old_bs_i, found_i); 580 } else { 581 // no match found so we have to append this bootstrap specifier to *merge_cp_p 582 append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p, THREAD); 583 new_bs_i = _operands_cur_length - 1; 584 } 585 } 586 return new_bs_i; 587 } // end find_or_append_operand() 588 589 590 void VM_RedefineClasses::finalize_operands_merge(constantPoolHandle merge_cp, TRAPS) { 591 if (merge_cp->operands() == NULL) { 592 return; 593 } 594 // Shrink the merge_cp operands 595 merge_cp->shrink_operands(_operands_cur_length, CHECK); 596 597 if (RC_TRACE_ENABLED(0x00040000)) { 598 // don't want to loop unless we are tracing 599 int count = 0; 600 for (int i = 1; i < _operands_index_map_p->length(); i++) { 601 int value = _operands_index_map_p->at(i); 602 if (value != -1) { 603 RC_TRACE_WITH_THREAD(0x00040000, THREAD, 604 ("operands_index_map[%d]: old=%d new=%d", count, i, value)); 605 count++; 606 } 607 } 608 } 609 // Clean-up 610 _operands_index_map_p = NULL; 611 _operands_cur_length = 0; 612 _operands_index_map_count = 0; 613 } // end finalize_operands_merge() 614 615 616 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions( 617 instanceKlassHandle the_class, 618 instanceKlassHandle scratch_class) { 619 int i; 620 621 // Check superclasses, or rather their names, since superclasses themselves can be 622 // requested to replace. 623 // Check for NULL superclass first since this might be java.lang.Object 624 if (the_class->super() != scratch_class->super() && 625 (the_class->super() == NULL || scratch_class->super() == NULL || 626 the_class->super()->name() != 627 scratch_class->super()->name())) { 628 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 629 } 630 631 // Check if the number, names and order of directly implemented interfaces are the same. 632 // I think in principle we should just check if the sets of names of directly implemented 633 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the 634 // .java file, also changes in .class file) should not matter. However, comparing sets is 635 // technically a bit more difficult, and, more importantly, I am not sure at present that the 636 // order of interfaces does not matter on the implementation level, i.e. that the VM does not 637 // rely on it somewhere. 638 Array<Klass*>* k_interfaces = the_class->local_interfaces(); 639 Array<Klass*>* k_new_interfaces = scratch_class->local_interfaces(); 640 int n_intfs = k_interfaces->length(); 641 if (n_intfs != k_new_interfaces->length()) { 642 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 643 } 644 for (i = 0; i < n_intfs; i++) { 645 if (k_interfaces->at(i)->name() != 646 k_new_interfaces->at(i)->name()) { 647 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; 648 } 649 } 650 651 // Check whether class is in the error init state. 652 if (the_class->is_in_error_state()) { 653 // TBD #5057930: special error code is needed in 1.6 654 return JVMTI_ERROR_INVALID_CLASS; 655 } 656 657 // Check whether class modifiers are the same. 658 jushort old_flags = (jushort) the_class->access_flags().get_flags(); 659 jushort new_flags = (jushort) scratch_class->access_flags().get_flags(); 660 if (old_flags != new_flags) { 661 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED; 662 } 663 664 // Check if the number, names, types and order of fields declared in these classes 665 // are the same. 666 JavaFieldStream old_fs(the_class); 667 JavaFieldStream new_fs(scratch_class); 668 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) { 669 // access 670 old_flags = old_fs.access_flags().as_short(); 671 new_flags = new_fs.access_flags().as_short(); 672 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) { 673 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 674 } 675 // offset 676 if (old_fs.offset() != new_fs.offset()) { 677 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 678 } 679 // name and signature 680 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index()); 681 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index()); 682 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index()); 683 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index()); 684 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) { 685 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 686 } 687 } 688 689 // If both streams aren't done then we have a differing number of 690 // fields. 691 if (!old_fs.done() || !new_fs.done()) { 692 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; 693 } 694 695 // Do a parallel walk through the old and new methods. Detect 696 // cases where they match (exist in both), have been added in 697 // the new methods, or have been deleted (exist only in the 698 // old methods). The class file parser places methods in order 699 // by method name, but does not order overloaded methods by 700 // signature. In order to determine what fate befell the methods, 701 // this code places the overloaded new methods that have matching 702 // old methods in the same order as the old methods and places 703 // new overloaded methods at the end of overloaded methods of 704 // that name. The code for this order normalization is adapted 705 // from the algorithm used in InstanceKlass::find_method(). 706 // Since we are swapping out of order entries as we find them, 707 // we only have to search forward through the overloaded methods. 708 // Methods which are added and have the same name as an existing 709 // method (but different signature) will be put at the end of 710 // the methods with that name, and the name mismatch code will 711 // handle them. 712 Array<Method*>* k_old_methods(the_class->methods()); 713 Array<Method*>* k_new_methods(scratch_class->methods()); 714 int n_old_methods = k_old_methods->length(); 715 int n_new_methods = k_new_methods->length(); 716 Thread* thread = Thread::current(); 717 718 int ni = 0; 719 int oi = 0; 720 while (true) { 721 Method* k_old_method; 722 Method* k_new_method; 723 enum { matched, added, deleted, undetermined } method_was = undetermined; 724 725 if (oi >= n_old_methods) { 726 if (ni >= n_new_methods) { 727 break; // we've looked at everything, done 728 } 729 // New method at the end 730 k_new_method = k_new_methods->at(ni); 731 method_was = added; 732 } else if (ni >= n_new_methods) { 733 // Old method, at the end, is deleted 734 k_old_method = k_old_methods->at(oi); 735 method_was = deleted; 736 } else { 737 // There are more methods in both the old and new lists 738 k_old_method = k_old_methods->at(oi); 739 k_new_method = k_new_methods->at(ni); 740 if (k_old_method->name() != k_new_method->name()) { 741 // Methods are sorted by method name, so a mismatch means added 742 // or deleted 743 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) { 744 method_was = added; 745 } else { 746 method_was = deleted; 747 } 748 } else if (k_old_method->signature() == k_new_method->signature()) { 749 // Both the name and signature match 750 method_was = matched; 751 } else { 752 // The name matches, but the signature doesn't, which means we have to 753 // search forward through the new overloaded methods. 754 int nj; // outside the loop for post-loop check 755 for (nj = ni + 1; nj < n_new_methods; nj++) { 756 Method* m = k_new_methods->at(nj); 757 if (k_old_method->name() != m->name()) { 758 // reached another method name so no more overloaded methods 759 method_was = deleted; 760 break; 761 } 762 if (k_old_method->signature() == m->signature()) { 763 // found a match so swap the methods 764 k_new_methods->at_put(ni, m); 765 k_new_methods->at_put(nj, k_new_method); 766 k_new_method = m; 767 method_was = matched; 768 break; 769 } 770 } 771 772 if (nj >= n_new_methods) { 773 // reached the end without a match; so method was deleted 774 method_was = deleted; 775 } 776 } 777 } 778 779 switch (method_was) { 780 case matched: 781 // methods match, be sure modifiers do too 782 old_flags = (jushort) k_old_method->access_flags().get_flags(); 783 new_flags = (jushort) k_new_method->access_flags().get_flags(); 784 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) { 785 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED; 786 } 787 { 788 u2 new_num = k_new_method->method_idnum(); 789 u2 old_num = k_old_method->method_idnum(); 790 if (new_num != old_num) { 791 Method* idnum_owner = scratch_class->method_with_idnum(old_num); 792 if (idnum_owner != NULL) { 793 // There is already a method assigned this idnum -- switch them 794 // Take current and original idnum from the new_method 795 idnum_owner->set_method_idnum(new_num); 796 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum()); 797 } 798 // Take current and original idnum from the old_method 799 k_new_method->set_method_idnum(old_num); 800 k_new_method->set_orig_method_idnum(k_old_method->orig_method_idnum()); 801 if (thread->has_pending_exception()) { 802 return JVMTI_ERROR_OUT_OF_MEMORY; 803 } 804 } 805 } 806 RC_TRACE(0x00008000, ("Method matched: new: %s [%d] == old: %s [%d]", 807 k_new_method->name_and_sig_as_C_string(), ni, 808 k_old_method->name_and_sig_as_C_string(), oi)); 809 // advance to next pair of methods 810 ++oi; 811 ++ni; 812 break; 813 case added: 814 // method added, see if it is OK 815 new_flags = (jushort) k_new_method->access_flags().get_flags(); 816 if ((new_flags & JVM_ACC_PRIVATE) == 0 817 // hack: private should be treated as final, but alas 818 || (new_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0 819 ) { 820 // new methods must be private 821 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED; 822 } 823 { 824 u2 num = the_class->next_method_idnum(); 825 if (num == ConstMethod::UNSET_IDNUM) { 826 // cannot add any more methods 827 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED; 828 } 829 u2 new_num = k_new_method->method_idnum(); 830 Method* idnum_owner = scratch_class->method_with_idnum(num); 831 if (idnum_owner != NULL) { 832 // There is already a method assigned this idnum -- switch them 833 // Take current and original idnum from the new_method 834 idnum_owner->set_method_idnum(new_num); 835 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum()); 836 } 837 k_new_method->set_method_idnum(num); 838 k_new_method->set_orig_method_idnum(num); 839 if (thread->has_pending_exception()) { 840 return JVMTI_ERROR_OUT_OF_MEMORY; 841 } 842 } 843 RC_TRACE(0x00008000, ("Method added: new: %s [%d]", 844 k_new_method->name_and_sig_as_C_string(), ni)); 845 ++ni; // advance to next new method 846 break; 847 case deleted: 848 // method deleted, see if it is OK 849 old_flags = (jushort) k_old_method->access_flags().get_flags(); 850 if ((old_flags & JVM_ACC_PRIVATE) == 0 851 // hack: private should be treated as final, but alas 852 || (old_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0 853 ) { 854 // deleted methods must be private 855 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED; 856 } 857 RC_TRACE(0x00008000, ("Method deleted: old: %s [%d]", 858 k_old_method->name_and_sig_as_C_string(), oi)); 859 ++oi; // advance to next old method 860 break; 861 default: 862 ShouldNotReachHere(); 863 } 864 } 865 866 return JVMTI_ERROR_NONE; 867 } 868 869 870 // Find new constant pool index value for old constant pool index value 871 // by seaching the index map. Returns zero (0) if there is no mapped 872 // value for the old constant pool index. 873 int VM_RedefineClasses::find_new_index(int old_index) { 874 if (_index_map_count == 0) { 875 // map is empty so nothing can be found 876 return 0; 877 } 878 879 if (old_index < 1 || old_index >= _index_map_p->length()) { 880 // The old_index is out of range so it is not mapped. This should 881 // not happen in regular constant pool merging use, but it can 882 // happen if a corrupt annotation is processed. 883 return 0; 884 } 885 886 int value = _index_map_p->at(old_index); 887 if (value == -1) { 888 // the old_index is not mapped 889 return 0; 890 } 891 892 return value; 893 } // end find_new_index() 894 895 896 // Find new bootstrap specifier index value for old bootstrap specifier index 897 // value by seaching the index map. Returns unused index (-1) if there is 898 // no mapped value for the old bootstrap specifier index. 899 int VM_RedefineClasses::find_new_operand_index(int old_index) { 900 if (_operands_index_map_count == 0) { 901 // map is empty so nothing can be found 902 return -1; 903 } 904 905 if (old_index == -1 || old_index >= _operands_index_map_p->length()) { 906 // The old_index is out of range so it is not mapped. 907 // This should not happen in regular constant pool merging use. 908 return -1; 909 } 910 911 int value = _operands_index_map_p->at(old_index); 912 if (value == -1) { 913 // the old_index is not mapped 914 return -1; 915 } 916 917 return value; 918 } // end find_new_operand_index() 919 920 921 // Returns true if the current mismatch is due to a resolved/unresolved 922 // class pair. Otherwise, returns false. 923 bool VM_RedefineClasses::is_unresolved_class_mismatch(constantPoolHandle cp1, 924 int index1, constantPoolHandle cp2, int index2) { 925 926 jbyte t1 = cp1->tag_at(index1).value(); 927 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) { 928 return false; // wrong entry type; not our special case 929 } 930 931 jbyte t2 = cp2->tag_at(index2).value(); 932 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) { 933 return false; // wrong entry type; not our special case 934 } 935 936 if (t1 == t2) { 937 return false; // not a mismatch; not our special case 938 } 939 940 char *s1 = cp1->klass_name_at(index1)->as_C_string(); 941 char *s2 = cp2->klass_name_at(index2)->as_C_string(); 942 if (strcmp(s1, s2) != 0) { 943 return false; // strings don't match; not our special case 944 } 945 946 return true; // made it through the gauntlet; this is our special case 947 } // end is_unresolved_class_mismatch() 948 949 950 jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) { 951 952 // For consistency allocate memory using os::malloc wrapper. 953 _scratch_classes = (Klass**) 954 os::malloc(sizeof(Klass*) * _class_count, mtClass); 955 if (_scratch_classes == NULL) { 956 return JVMTI_ERROR_OUT_OF_MEMORY; 957 } 958 // Zero initialize the _scratch_classes array. 959 for (int i = 0; i < _class_count; i++) { 960 _scratch_classes[i] = NULL; 961 } 962 963 ResourceMark rm(THREAD); 964 965 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current()); 966 // state can only be NULL if the current thread is exiting which 967 // should not happen since we're trying to do a RedefineClasses 968 guarantee(state != NULL, "exiting thread calling load_new_class_versions"); 969 for (int i = 0; i < _class_count; i++) { 970 // Create HandleMark so that any handles created while loading new class 971 // versions are deleted. Constant pools are deallocated while merging 972 // constant pools 973 HandleMark hm(THREAD); 974 975 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass); 976 // classes for primitives cannot be redefined 977 if (!is_modifiable_class(mirror)) { 978 return JVMTI_ERROR_UNMODIFIABLE_CLASS; 979 } 980 Klass* the_class_oop = java_lang_Class::as_Klass(mirror); 981 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop); 982 Symbol* the_class_sym = the_class->name(); 983 984 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 985 RC_TRACE_WITH_THREAD(0x00000001, THREAD, 986 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)", 987 the_class->external_name(), _class_load_kind, 988 os::available_memory() >> 10)); 989 990 ClassFileStream st((u1*) _class_defs[i].class_bytes, 991 _class_defs[i].class_byte_count, (char *)"__VM_RedefineClasses__"); 992 993 // Parse the stream. 994 Handle the_class_loader(THREAD, the_class->class_loader()); 995 Handle protection_domain(THREAD, the_class->protection_domain()); 996 // Set redefined class handle in JvmtiThreadState class. 997 // This redefined class is sent to agent event handler for class file 998 // load hook event. 999 state->set_class_being_redefined(&the_class, _class_load_kind); 1000 1001 Klass* k = SystemDictionary::parse_stream(the_class_sym, 1002 the_class_loader, 1003 protection_domain, 1004 &st, 1005 THREAD); 1006 // Clear class_being_redefined just to be sure. 1007 state->clear_class_being_redefined(); 1008 1009 // TODO: if this is retransform, and nothing changed we can skip it 1010 1011 instanceKlassHandle scratch_class (THREAD, k); 1012 1013 // Need to clean up allocated InstanceKlass if there's an error so assign 1014 // the result here. Caller deallocates all the scratch classes in case of 1015 // an error. 1016 _scratch_classes[i] = k; 1017 1018 if (HAS_PENDING_EXCEPTION) { 1019 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1020 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1021 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("parse_stream exception: '%s'", 1022 ex_name->as_C_string())); 1023 CLEAR_PENDING_EXCEPTION; 1024 1025 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) { 1026 return JVMTI_ERROR_UNSUPPORTED_VERSION; 1027 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) { 1028 return JVMTI_ERROR_INVALID_CLASS_FORMAT; 1029 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) { 1030 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION; 1031 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) { 1032 // The message will be "XXX (wrong name: YYY)" 1033 return JVMTI_ERROR_NAMES_DONT_MATCH; 1034 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1035 return JVMTI_ERROR_OUT_OF_MEMORY; 1036 } else { // Just in case more exceptions can be thrown.. 1037 return JVMTI_ERROR_FAILS_VERIFICATION; 1038 } 1039 } 1040 1041 // Ensure class is linked before redefine 1042 if (!the_class->is_linked()) { 1043 the_class->link_class(THREAD); 1044 if (HAS_PENDING_EXCEPTION) { 1045 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1046 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1047 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("link_class exception: '%s'", 1048 ex_name->as_C_string())); 1049 CLEAR_PENDING_EXCEPTION; 1050 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1051 return JVMTI_ERROR_OUT_OF_MEMORY; 1052 } else { 1053 return JVMTI_ERROR_INTERNAL; 1054 } 1055 } 1056 } 1057 1058 // Do the validity checks in compare_and_normalize_class_versions() 1059 // before verifying the byte codes. By doing these checks first, we 1060 // limit the number of functions that require redirection from 1061 // the_class to scratch_class. In particular, we don't have to 1062 // modify JNI GetSuperclass() and thus won't change its performance. 1063 jvmtiError res = compare_and_normalize_class_versions(the_class, 1064 scratch_class); 1065 if (res != JVMTI_ERROR_NONE) { 1066 return res; 1067 } 1068 1069 // verify what the caller passed us 1070 { 1071 // The bug 6214132 caused the verification to fail. 1072 // Information about the_class and scratch_class is temporarily 1073 // recorded into jvmtiThreadState. This data is used to redirect 1074 // the_class to scratch_class in the JVM_* functions called by the 1075 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed 1076 // description. 1077 RedefineVerifyMark rvm(&the_class, &scratch_class, state); 1078 Verifier::verify( 1079 scratch_class, Verifier::ThrowException, true, THREAD); 1080 } 1081 1082 if (HAS_PENDING_EXCEPTION) { 1083 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1084 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1085 RC_TRACE_WITH_THREAD(0x00000002, THREAD, 1086 ("verify_byte_codes exception: '%s'", ex_name->as_C_string())); 1087 CLEAR_PENDING_EXCEPTION; 1088 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1089 return JVMTI_ERROR_OUT_OF_MEMORY; 1090 } else { 1091 // tell the caller the bytecodes are bad 1092 return JVMTI_ERROR_FAILS_VERIFICATION; 1093 } 1094 } 1095 1096 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD); 1097 if (HAS_PENDING_EXCEPTION) { 1098 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1099 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1100 RC_TRACE_WITH_THREAD(0x00000002, THREAD, 1101 ("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string())); 1102 CLEAR_PENDING_EXCEPTION; 1103 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1104 return JVMTI_ERROR_OUT_OF_MEMORY; 1105 } else { 1106 return JVMTI_ERROR_INTERNAL; 1107 } 1108 } 1109 1110 if (VerifyMergedCPBytecodes) { 1111 // verify what we have done during constant pool merging 1112 { 1113 RedefineVerifyMark rvm(&the_class, &scratch_class, state); 1114 Verifier::verify(scratch_class, Verifier::ThrowException, true, THREAD); 1115 } 1116 1117 if (HAS_PENDING_EXCEPTION) { 1118 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1119 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1120 RC_TRACE_WITH_THREAD(0x00000002, THREAD, 1121 ("verify_byte_codes post merge-CP exception: '%s'", 1122 ex_name->as_C_string())); 1123 CLEAR_PENDING_EXCEPTION; 1124 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1125 return JVMTI_ERROR_OUT_OF_MEMORY; 1126 } else { 1127 // tell the caller that constant pool merging screwed up 1128 return JVMTI_ERROR_INTERNAL; 1129 } 1130 } 1131 } 1132 1133 Rewriter::rewrite(scratch_class, THREAD); 1134 if (!HAS_PENDING_EXCEPTION) { 1135 scratch_class->link_methods(THREAD); 1136 } 1137 if (HAS_PENDING_EXCEPTION) { 1138 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1139 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1140 RC_TRACE_WITH_THREAD(0x00000002, THREAD, 1141 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string())); 1142 CLEAR_PENDING_EXCEPTION; 1143 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { 1144 return JVMTI_ERROR_OUT_OF_MEMORY; 1145 } else { 1146 return JVMTI_ERROR_INTERNAL; 1147 } 1148 } 1149 1150 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1151 RC_TRACE_WITH_THREAD(0x00000001, THREAD, 1152 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)", 1153 the_class->external_name(), os::available_memory() >> 10)); 1154 } 1155 1156 return JVMTI_ERROR_NONE; 1157 } 1158 1159 1160 // Map old_index to new_index as needed. scratch_cp is only needed 1161 // for RC_TRACE() calls. 1162 void VM_RedefineClasses::map_index(constantPoolHandle scratch_cp, 1163 int old_index, int new_index) { 1164 if (find_new_index(old_index) != 0) { 1165 // old_index is already mapped 1166 return; 1167 } 1168 1169 if (old_index == new_index) { 1170 // no mapping is needed 1171 return; 1172 } 1173 1174 _index_map_p->at_put(old_index, new_index); 1175 _index_map_count++; 1176 1177 RC_TRACE(0x00040000, ("mapped tag %d at index %d to %d", 1178 scratch_cp->tag_at(old_index).value(), old_index, new_index)); 1179 } // end map_index() 1180 1181 1182 // Map old_index to new_index as needed. 1183 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) { 1184 if (find_new_operand_index(old_index) != -1) { 1185 // old_index is already mapped 1186 return; 1187 } 1188 1189 if (old_index == new_index) { 1190 // no mapping is needed 1191 return; 1192 } 1193 1194 _operands_index_map_p->at_put(old_index, new_index); 1195 _operands_index_map_count++; 1196 1197 RC_TRACE(0x00040000, ("mapped bootstrap specifier at index %d to %d", old_index, new_index)); 1198 } // end map_index() 1199 1200 1201 // Merge old_cp and scratch_cp and return the results of the merge via 1202 // merge_cp_p. The number of entries in *merge_cp_p is returned via 1203 // merge_cp_length_p. The entries in old_cp occupy the same locations 1204 // in *merge_cp_p. Also creates a map of indices from entries in 1205 // scratch_cp to the corresponding entry in *merge_cp_p. Index map 1206 // entries are only created for entries in scratch_cp that occupy a 1207 // different location in *merged_cp_p. 1208 bool VM_RedefineClasses::merge_constant_pools(constantPoolHandle old_cp, 1209 constantPoolHandle scratch_cp, constantPoolHandle *merge_cp_p, 1210 int *merge_cp_length_p, TRAPS) { 1211 1212 if (merge_cp_p == NULL) { 1213 assert(false, "caller must provide scratch constantPool"); 1214 return false; // robustness 1215 } 1216 if (merge_cp_length_p == NULL) { 1217 assert(false, "caller must provide scratch CP length"); 1218 return false; // robustness 1219 } 1220 // Worst case we need old_cp->length() + scratch_cp()->length(), 1221 // but the caller might be smart so make sure we have at least 1222 // the minimum. 1223 if ((*merge_cp_p)->length() < old_cp->length()) { 1224 assert(false, "merge area too small"); 1225 return false; // robustness 1226 } 1227 1228 RC_TRACE_WITH_THREAD(0x00010000, THREAD, 1229 ("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(), 1230 scratch_cp->length())); 1231 1232 { 1233 // Pass 0: 1234 // The old_cp is copied to *merge_cp_p; this means that any code 1235 // using old_cp does not have to change. This work looks like a 1236 // perfect fit for ConstantPool*::copy_cp_to(), but we need to 1237 // handle one special case: 1238 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass 1239 // This will make verification happy. 1240 1241 int old_i; // index into old_cp 1242 1243 // index zero (0) is not used in constantPools 1244 for (old_i = 1; old_i < old_cp->length(); old_i++) { 1245 // leave debugging crumb 1246 jbyte old_tag = old_cp->tag_at(old_i).value(); 1247 switch (old_tag) { 1248 case JVM_CONSTANT_Class: 1249 case JVM_CONSTANT_UnresolvedClass: 1250 // revert the copy to JVM_CONSTANT_UnresolvedClass 1251 // May be resolving while calling this so do the same for 1252 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition) 1253 (*merge_cp_p)->unresolved_klass_at_put(old_i, 1254 old_cp->klass_name_at(old_i)); 1255 break; 1256 1257 case JVM_CONSTANT_Double: 1258 case JVM_CONSTANT_Long: 1259 // just copy the entry to *merge_cp_p, but double and long take 1260 // two constant pool entries 1261 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0); 1262 old_i++; 1263 break; 1264 1265 default: 1266 // just copy the entry to *merge_cp_p 1267 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0); 1268 break; 1269 } 1270 } // end for each old_cp entry 1271 1272 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_0); 1273 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_0); 1274 1275 // We don't need to sanity check that *merge_cp_length_p is within 1276 // *merge_cp_p bounds since we have the minimum on-entry check above. 1277 (*merge_cp_length_p) = old_i; 1278 } 1279 1280 // merge_cp_len should be the same as old_cp->length() at this point 1281 // so this trace message is really a "warm-and-breathing" message. 1282 RC_TRACE_WITH_THREAD(0x00020000, THREAD, 1283 ("after pass 0: merge_cp_len=%d", *merge_cp_length_p)); 1284 1285 int scratch_i; // index into scratch_cp 1286 { 1287 // Pass 1a: 1288 // Compare scratch_cp entries to the old_cp entries that we have 1289 // already copied to *merge_cp_p. In this pass, we are eliminating 1290 // exact duplicates (matching entry at same index) so we only 1291 // compare entries in the common indice range. 1292 int increment = 1; 1293 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length()); 1294 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) { 1295 switch (scratch_cp->tag_at(scratch_i).value()) { 1296 case JVM_CONSTANT_Double: 1297 case JVM_CONSTANT_Long: 1298 // double and long take two constant pool entries 1299 increment = 2; 1300 break; 1301 1302 default: 1303 increment = 1; 1304 break; 1305 } 1306 1307 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p, 1308 scratch_i, CHECK_0); 1309 if (match) { 1310 // found a match at the same index so nothing more to do 1311 continue; 1312 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i, 1313 *merge_cp_p, scratch_i)) { 1314 // The mismatch in compare_entry_to() above is because of a 1315 // resolved versus unresolved class entry at the same index 1316 // with the same string value. Since Pass 0 reverted any 1317 // class entries to unresolved class entries in *merge_cp_p, 1318 // we go with the unresolved class entry. 1319 continue; 1320 } 1321 1322 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, 1323 CHECK_0); 1324 if (found_i != 0) { 1325 guarantee(found_i != scratch_i, 1326 "compare_entry_to() and find_matching_entry() do not agree"); 1327 1328 // Found a matching entry somewhere else in *merge_cp_p so 1329 // just need a mapping entry. 1330 map_index(scratch_cp, scratch_i, found_i); 1331 continue; 1332 } 1333 1334 // The find_matching_entry() call above could fail to find a match 1335 // due to a resolved versus unresolved class or string entry situation 1336 // like we solved above with the is_unresolved_*_mismatch() calls. 1337 // However, we would have to call is_unresolved_*_mismatch() over 1338 // all of *merge_cp_p (potentially) and that doesn't seem to be 1339 // worth the time. 1340 1341 // No match found so we have to append this entry and any unique 1342 // referenced entries to *merge_cp_p. 1343 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p, 1344 CHECK_0); 1345 } 1346 } 1347 1348 RC_TRACE_WITH_THREAD(0x00020000, THREAD, 1349 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", 1350 *merge_cp_length_p, scratch_i, _index_map_count)); 1351 1352 if (scratch_i < scratch_cp->length()) { 1353 // Pass 1b: 1354 // old_cp is smaller than scratch_cp so there are entries in 1355 // scratch_cp that we have not yet processed. We take care of 1356 // those now. 1357 int increment = 1; 1358 for (; scratch_i < scratch_cp->length(); scratch_i += increment) { 1359 switch (scratch_cp->tag_at(scratch_i).value()) { 1360 case JVM_CONSTANT_Double: 1361 case JVM_CONSTANT_Long: 1362 // double and long take two constant pool entries 1363 increment = 2; 1364 break; 1365 1366 default: 1367 increment = 1; 1368 break; 1369 } 1370 1371 int found_i = 1372 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0); 1373 if (found_i != 0) { 1374 // Found a matching entry somewhere else in *merge_cp_p so 1375 // just need a mapping entry. 1376 map_index(scratch_cp, scratch_i, found_i); 1377 continue; 1378 } 1379 1380 // No match found so we have to append this entry and any unique 1381 // referenced entries to *merge_cp_p. 1382 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p, 1383 CHECK_0); 1384 } 1385 1386 RC_TRACE_WITH_THREAD(0x00020000, THREAD, 1387 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", 1388 *merge_cp_length_p, scratch_i, _index_map_count)); 1389 } 1390 finalize_operands_merge(*merge_cp_p, THREAD); 1391 1392 return true; 1393 } // end merge_constant_pools() 1394 1395 1396 // Scoped object to clean up the constant pool(s) created for merging 1397 class MergeCPCleaner { 1398 ClassLoaderData* _loader_data; 1399 ConstantPool* _cp; 1400 ConstantPool* _scratch_cp; 1401 public: 1402 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) : 1403 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {} 1404 ~MergeCPCleaner() { 1405 _loader_data->add_to_deallocate_list(_cp); 1406 if (_scratch_cp != NULL) { 1407 _loader_data->add_to_deallocate_list(_scratch_cp); 1408 } 1409 } 1410 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; } 1411 }; 1412 1413 // Merge constant pools between the_class and scratch_class and 1414 // potentially rewrite bytecodes in scratch_class to use the merged 1415 // constant pool. 1416 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite( 1417 instanceKlassHandle the_class, instanceKlassHandle scratch_class, 1418 TRAPS) { 1419 // worst case merged constant pool length is old and new combined 1420 int merge_cp_length = the_class->constants()->length() 1421 + scratch_class->constants()->length(); 1422 1423 // Constant pools are not easily reused so we allocate a new one 1424 // each time. 1425 // merge_cp is created unsafe for concurrent GC processing. It 1426 // should be marked safe before discarding it. Even though 1427 // garbage, if it crosses a card boundary, it may be scanned 1428 // in order to find the start of the first complete object on the card. 1429 ClassLoaderData* loader_data = the_class->class_loader_data(); 1430 ConstantPool* merge_cp_oop = 1431 ConstantPool::allocate(loader_data, 1432 merge_cp_length, 1433 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1434 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop); 1435 1436 HandleMark hm(THREAD); // make sure handles are cleared before 1437 // MergeCPCleaner clears out merge_cp_oop 1438 constantPoolHandle merge_cp(THREAD, merge_cp_oop); 1439 1440 // Get constants() from the old class because it could have been rewritten 1441 // while we were at a safepoint allocating a new constant pool. 1442 constantPoolHandle old_cp(THREAD, the_class->constants()); 1443 constantPoolHandle scratch_cp(THREAD, scratch_class->constants()); 1444 1445 // If the length changed, the class was redefined out from under us. Return 1446 // an error. 1447 if (merge_cp_length != the_class->constants()->length() 1448 + scratch_class->constants()->length()) { 1449 return JVMTI_ERROR_INTERNAL; 1450 } 1451 1452 // Update the version number of the constant pool 1453 merge_cp->increment_and_save_version(old_cp->version()); 1454 1455 ResourceMark rm(THREAD); 1456 _index_map_count = 0; 1457 _index_map_p = new intArray(scratch_cp->length(), -1); 1458 1459 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands()); 1460 _operands_index_map_count = 0; 1461 _operands_index_map_p = new intArray( 1462 ConstantPool::operand_array_length(scratch_cp->operands()), -1); 1463 1464 // reference to the cp holder is needed for copy_operands() 1465 merge_cp->set_pool_holder(scratch_class()); 1466 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp, 1467 &merge_cp_length, THREAD); 1468 merge_cp->set_pool_holder(NULL); 1469 1470 if (!result) { 1471 // The merge can fail due to memory allocation failure or due 1472 // to robustness checks. 1473 return JVMTI_ERROR_INTERNAL; 1474 } 1475 1476 RC_TRACE_WITH_THREAD(0x00010000, THREAD, 1477 ("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count)); 1478 1479 if (_index_map_count == 0) { 1480 // there is nothing to map between the new and merged constant pools 1481 1482 if (old_cp->length() == scratch_cp->length()) { 1483 // The old and new constant pools are the same length and the 1484 // index map is empty. This means that the three constant pools 1485 // are equivalent (but not the same). Unfortunately, the new 1486 // constant pool has not gone through link resolution nor have 1487 // the new class bytecodes gone through constant pool cache 1488 // rewriting so we can't use the old constant pool with the new 1489 // class. 1490 1491 // toss the merged constant pool at return 1492 } else if (old_cp->length() < scratch_cp->length()) { 1493 // The old constant pool has fewer entries than the new constant 1494 // pool and the index map is empty. This means the new constant 1495 // pool is a superset of the old constant pool. However, the old 1496 // class bytecodes have already gone through constant pool cache 1497 // rewriting so we can't use the new constant pool with the old 1498 // class. 1499 1500 // toss the merged constant pool at return 1501 } else { 1502 // The old constant pool has more entries than the new constant 1503 // pool and the index map is empty. This means that both the old 1504 // and merged constant pools are supersets of the new constant 1505 // pool. 1506 1507 // Replace the new constant pool with a shrunken copy of the 1508 // merged constant pool 1509 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, 1510 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1511 // The new constant pool replaces scratch_cp so have cleaner clean it up. 1512 // It can't be cleaned up while there are handles to it. 1513 cp_cleaner.add_scratch_cp(scratch_cp()); 1514 } 1515 } else { 1516 if (RC_TRACE_ENABLED(0x00040000)) { 1517 // don't want to loop unless we are tracing 1518 int count = 0; 1519 for (int i = 1; i < _index_map_p->length(); i++) { 1520 int value = _index_map_p->at(i); 1521 1522 if (value != -1) { 1523 RC_TRACE_WITH_THREAD(0x00040000, THREAD, 1524 ("index_map[%d]: old=%d new=%d", count, i, value)); 1525 count++; 1526 } 1527 } 1528 } 1529 1530 // We have entries mapped between the new and merged constant pools 1531 // so we have to rewrite some constant pool references. 1532 if (!rewrite_cp_refs(scratch_class, THREAD)) { 1533 return JVMTI_ERROR_INTERNAL; 1534 } 1535 1536 // Replace the new constant pool with a shrunken copy of the 1537 // merged constant pool so now the rewritten bytecodes have 1538 // valid references; the previous new constant pool will get 1539 // GCed. 1540 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, 1541 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); 1542 // The new constant pool replaces scratch_cp so have cleaner clean it up. 1543 // It can't be cleaned up while there are handles to it. 1544 cp_cleaner.add_scratch_cp(scratch_cp()); 1545 } 1546 1547 return JVMTI_ERROR_NONE; 1548 } // end merge_cp_and_rewrite() 1549 1550 1551 // Rewrite constant pool references in klass scratch_class. 1552 bool VM_RedefineClasses::rewrite_cp_refs(instanceKlassHandle scratch_class, 1553 TRAPS) { 1554 1555 // rewrite constant pool references in the methods: 1556 if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) { 1557 // propagate failure back to caller 1558 return false; 1559 } 1560 1561 // rewrite constant pool references in the class_annotations: 1562 if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) { 1563 // propagate failure back to caller 1564 return false; 1565 } 1566 1567 // rewrite constant pool references in the fields_annotations: 1568 if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) { 1569 // propagate failure back to caller 1570 return false; 1571 } 1572 1573 // rewrite constant pool references in the methods_annotations: 1574 if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) { 1575 // propagate failure back to caller 1576 return false; 1577 } 1578 1579 // rewrite constant pool references in the methods_parameter_annotations: 1580 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class, 1581 THREAD)) { 1582 // propagate failure back to caller 1583 return false; 1584 } 1585 1586 // rewrite constant pool references in the methods_default_annotations: 1587 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class, 1588 THREAD)) { 1589 // propagate failure back to caller 1590 return false; 1591 } 1592 1593 // rewrite constant pool references in the class_type_annotations: 1594 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class, THREAD)) { 1595 // propagate failure back to caller 1596 return false; 1597 } 1598 1599 // rewrite constant pool references in the fields_type_annotations: 1600 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class, THREAD)) { 1601 // propagate failure back to caller 1602 return false; 1603 } 1604 1605 // rewrite constant pool references in the methods_type_annotations: 1606 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class, THREAD)) { 1607 // propagate failure back to caller 1608 return false; 1609 } 1610 1611 // There can be type annotations in the Code part of a method_info attribute. 1612 // These annotations are not accessible, even by reflection. 1613 // Currently they are not even parsed by the ClassFileParser. 1614 // If runtime access is added they will also need to be rewritten. 1615 1616 // rewrite source file name index: 1617 u2 source_file_name_idx = scratch_class->source_file_name_index(); 1618 if (source_file_name_idx != 0) { 1619 u2 new_source_file_name_idx = find_new_index(source_file_name_idx); 1620 if (new_source_file_name_idx != 0) { 1621 scratch_class->set_source_file_name_index(new_source_file_name_idx); 1622 } 1623 } 1624 1625 // rewrite class generic signature index: 1626 u2 generic_signature_index = scratch_class->generic_signature_index(); 1627 if (generic_signature_index != 0) { 1628 u2 new_generic_signature_index = find_new_index(generic_signature_index); 1629 if (new_generic_signature_index != 0) { 1630 scratch_class->set_generic_signature_index(new_generic_signature_index); 1631 } 1632 } 1633 1634 return true; 1635 } // end rewrite_cp_refs() 1636 1637 // Rewrite constant pool references in the methods. 1638 bool VM_RedefineClasses::rewrite_cp_refs_in_methods( 1639 instanceKlassHandle scratch_class, TRAPS) { 1640 1641 Array<Method*>* methods = scratch_class->methods(); 1642 1643 if (methods == NULL || methods->length() == 0) { 1644 // no methods so nothing to do 1645 return true; 1646 } 1647 1648 // rewrite constant pool references in the methods: 1649 for (int i = methods->length() - 1; i >= 0; i--) { 1650 methodHandle method(THREAD, methods->at(i)); 1651 methodHandle new_method; 1652 rewrite_cp_refs_in_method(method, &new_method, THREAD); 1653 if (!new_method.is_null()) { 1654 // the method has been replaced so save the new method version 1655 // even in the case of an exception. original method is on the 1656 // deallocation list. 1657 methods->at_put(i, new_method()); 1658 } 1659 if (HAS_PENDING_EXCEPTION) { 1660 Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); 1661 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark 1662 RC_TRACE_WITH_THREAD(0x00000002, THREAD, 1663 ("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string())); 1664 // Need to clear pending exception here as the super caller sets 1665 // the JVMTI_ERROR_INTERNAL if the returned value is false. 1666 CLEAR_PENDING_EXCEPTION; 1667 return false; 1668 } 1669 } 1670 1671 return true; 1672 } 1673 1674 1675 // Rewrite constant pool references in the specific method. This code 1676 // was adapted from Rewriter::rewrite_method(). 1677 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method, 1678 methodHandle *new_method_p, TRAPS) { 1679 1680 *new_method_p = methodHandle(); // default is no new method 1681 1682 // We cache a pointer to the bytecodes here in code_base. If GC 1683 // moves the Method*, then the bytecodes will also move which 1684 // will likely cause a crash. We create a No_Safepoint_Verifier 1685 // object to detect whether we pass a possible safepoint in this 1686 // code block. 1687 No_Safepoint_Verifier nsv; 1688 1689 // Bytecodes and their length 1690 address code_base = method->code_base(); 1691 int code_length = method->code_size(); 1692 1693 int bc_length; 1694 for (int bci = 0; bci < code_length; bci += bc_length) { 1695 address bcp = code_base + bci; 1696 Bytecodes::Code c = (Bytecodes::Code)(*bcp); 1697 1698 bc_length = Bytecodes::length_for(c); 1699 if (bc_length == 0) { 1700 // More complicated bytecodes report a length of zero so 1701 // we have to try again a slightly different way. 1702 bc_length = Bytecodes::length_at(method(), bcp); 1703 } 1704 1705 assert(bc_length != 0, "impossible bytecode length"); 1706 1707 switch (c) { 1708 case Bytecodes::_ldc: 1709 { 1710 int cp_index = *(bcp + 1); 1711 int new_index = find_new_index(cp_index); 1712 1713 if (StressLdcRewrite && new_index == 0) { 1714 // If we are stressing ldc -> ldc_w rewriting, then we 1715 // always need a new_index value. 1716 new_index = cp_index; 1717 } 1718 if (new_index != 0) { 1719 // the original index is mapped so we have more work to do 1720 if (!StressLdcRewrite && new_index <= max_jubyte) { 1721 // The new value can still use ldc instead of ldc_w 1722 // unless we are trying to stress ldc -> ldc_w rewriting 1723 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 1724 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), 1725 bcp, cp_index, new_index)); 1726 *(bcp + 1) = new_index; 1727 } else { 1728 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 1729 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d", 1730 Bytecodes::name(c), bcp, cp_index, new_index)); 1731 // the new value needs ldc_w instead of ldc 1732 u_char inst_buffer[4]; // max instruction size is 4 bytes 1733 bcp = (address)inst_buffer; 1734 // construct new instruction sequence 1735 *bcp = Bytecodes::_ldc_w; 1736 bcp++; 1737 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w. 1738 // See comment below for difference between put_Java_u2() 1739 // and put_native_u2(). 1740 Bytes::put_Java_u2(bcp, new_index); 1741 1742 Relocator rc(method, NULL /* no RelocatorListener needed */); 1743 methodHandle m; 1744 { 1745 Pause_No_Safepoint_Verifier pnsv(&nsv); 1746 1747 // ldc is 2 bytes and ldc_w is 3 bytes 1748 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK); 1749 } 1750 1751 // return the new method so that the caller can update 1752 // the containing class 1753 *new_method_p = method = m; 1754 // switch our bytecode processing loop from the old method 1755 // to the new method 1756 code_base = method->code_base(); 1757 code_length = method->code_size(); 1758 bcp = code_base + bci; 1759 c = (Bytecodes::Code)(*bcp); 1760 bc_length = Bytecodes::length_for(c); 1761 assert(bc_length != 0, "sanity check"); 1762 } // end we need ldc_w instead of ldc 1763 } // end if there is a mapped index 1764 } break; 1765 1766 // these bytecodes have a two-byte constant pool index 1767 case Bytecodes::_anewarray : // fall through 1768 case Bytecodes::_checkcast : // fall through 1769 case Bytecodes::_getfield : // fall through 1770 case Bytecodes::_getstatic : // fall through 1771 case Bytecodes::_instanceof : // fall through 1772 case Bytecodes::_invokedynamic : // fall through 1773 case Bytecodes::_invokeinterface: // fall through 1774 case Bytecodes::_invokespecial : // fall through 1775 case Bytecodes::_invokestatic : // fall through 1776 case Bytecodes::_invokevirtual : // fall through 1777 case Bytecodes::_ldc_w : // fall through 1778 case Bytecodes::_ldc2_w : // fall through 1779 case Bytecodes::_multianewarray : // fall through 1780 case Bytecodes::_new : // fall through 1781 case Bytecodes::_putfield : // fall through 1782 case Bytecodes::_putstatic : 1783 { 1784 address p = bcp + 1; 1785 int cp_index = Bytes::get_Java_u2(p); 1786 int new_index = find_new_index(cp_index); 1787 if (new_index != 0) { 1788 // the original index is mapped so update w/ new value 1789 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 1790 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), 1791 bcp, cp_index, new_index)); 1792 // Rewriter::rewrite_method() uses put_native_u2() in this 1793 // situation because it is reusing the constant pool index 1794 // location for a native index into the ConstantPoolCache. 1795 // Since we are updating the constant pool index prior to 1796 // verification and ConstantPoolCache initialization, we 1797 // need to keep the new index in Java byte order. 1798 Bytes::put_Java_u2(p, new_index); 1799 } 1800 } break; 1801 } 1802 } // end for each bytecode 1803 1804 // We also need to rewrite the parameter name indexes, if there is 1805 // method parameter data present 1806 if(method->has_method_parameters()) { 1807 const int len = method->method_parameters_length(); 1808 MethodParametersElement* elem = method->method_parameters_start(); 1809 1810 for (int i = 0; i < len; i++) { 1811 const u2 cp_index = elem[i].name_cp_index; 1812 const u2 new_cp_index = find_new_index(cp_index); 1813 if (new_cp_index != 0) { 1814 elem[i].name_cp_index = new_cp_index; 1815 } 1816 } 1817 } 1818 } // end rewrite_cp_refs_in_method() 1819 1820 1821 // Rewrite constant pool references in the class_annotations field. 1822 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations( 1823 instanceKlassHandle scratch_class, TRAPS) { 1824 1825 AnnotationArray* class_annotations = scratch_class->class_annotations(); 1826 if (class_annotations == NULL || class_annotations->length() == 0) { 1827 // no class_annotations so nothing to do 1828 return true; 1829 } 1830 1831 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1832 ("class_annotations length=%d", class_annotations->length())); 1833 1834 int byte_i = 0; // byte index into class_annotations 1835 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i, 1836 THREAD); 1837 } 1838 1839 1840 // Rewrite constant pool references in an annotations typeArray. This 1841 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute 1842 // that is described in section 4.8.15 of the 2nd-edition of the VM spec: 1843 // 1844 // annotations_typeArray { 1845 // u2 num_annotations; 1846 // annotation annotations[num_annotations]; 1847 // } 1848 // 1849 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray( 1850 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) { 1851 1852 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 1853 // not enough room for num_annotations field 1854 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1855 ("length() is too small for num_annotations field")); 1856 return false; 1857 } 1858 1859 u2 num_annotations = Bytes::get_Java_u2((address) 1860 annotations_typeArray->adr_at(byte_i_ref)); 1861 byte_i_ref += 2; 1862 1863 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1864 ("num_annotations=%d", num_annotations)); 1865 1866 int calc_num_annotations = 0; 1867 for (; calc_num_annotations < num_annotations; calc_num_annotations++) { 1868 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, 1869 byte_i_ref, THREAD)) { 1870 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1871 ("bad annotation_struct at %d", calc_num_annotations)); 1872 // propagate failure back to caller 1873 return false; 1874 } 1875 } 1876 assert(num_annotations == calc_num_annotations, "sanity check"); 1877 1878 return true; 1879 } // end rewrite_cp_refs_in_annotations_typeArray() 1880 1881 1882 // Rewrite constant pool references in the annotation struct portion of 1883 // an annotations_typeArray. This "structure" is from section 4.8.15 of 1884 // the 2nd-edition of the VM spec: 1885 // 1886 // struct annotation { 1887 // u2 type_index; 1888 // u2 num_element_value_pairs; 1889 // { 1890 // u2 element_name_index; 1891 // element_value value; 1892 // } element_value_pairs[num_element_value_pairs]; 1893 // } 1894 // 1895 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct( 1896 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) { 1897 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) { 1898 // not enough room for smallest annotation_struct 1899 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1900 ("length() is too small for annotation_struct")); 1901 return false; 1902 } 1903 1904 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray, 1905 byte_i_ref, "mapped old type_index=%d", THREAD); 1906 1907 u2 num_element_value_pairs = Bytes::get_Java_u2((address) 1908 annotations_typeArray->adr_at(byte_i_ref)); 1909 byte_i_ref += 2; 1910 1911 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1912 ("type_index=%d num_element_value_pairs=%d", type_index, 1913 num_element_value_pairs)); 1914 1915 int calc_num_element_value_pairs = 0; 1916 for (; calc_num_element_value_pairs < num_element_value_pairs; 1917 calc_num_element_value_pairs++) { 1918 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 1919 // not enough room for another element_name_index, let alone 1920 // the rest of another component 1921 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1922 ("length() is too small for element_name_index")); 1923 return false; 1924 } 1925 1926 u2 element_name_index = rewrite_cp_ref_in_annotation_data( 1927 annotations_typeArray, byte_i_ref, 1928 "mapped old element_name_index=%d", THREAD); 1929 1930 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1931 ("element_name_index=%d", element_name_index)); 1932 1933 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, 1934 byte_i_ref, THREAD)) { 1935 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 1936 ("bad element_value at %d", calc_num_element_value_pairs)); 1937 // propagate failure back to caller 1938 return false; 1939 } 1940 } // end for each component 1941 assert(num_element_value_pairs == calc_num_element_value_pairs, 1942 "sanity check"); 1943 1944 return true; 1945 } // end rewrite_cp_refs_in_annotation_struct() 1946 1947 1948 // Rewrite a constant pool reference at the current position in 1949 // annotations_typeArray if needed. Returns the original constant 1950 // pool reference if a rewrite was not needed or the new constant 1951 // pool reference if a rewrite was needed. 1952 PRAGMA_DIAG_PUSH 1953 PRAGMA_FORMAT_NONLITERAL_IGNORED 1954 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data( 1955 AnnotationArray* annotations_typeArray, int &byte_i_ref, 1956 const char * trace_mesg, TRAPS) { 1957 1958 address cp_index_addr = (address) 1959 annotations_typeArray->adr_at(byte_i_ref); 1960 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr); 1961 u2 new_cp_index = find_new_index(old_cp_index); 1962 if (new_cp_index != 0) { 1963 RC_TRACE_WITH_THREAD(0x02000000, THREAD, (trace_mesg, old_cp_index)); 1964 Bytes::put_Java_u2(cp_index_addr, new_cp_index); 1965 old_cp_index = new_cp_index; 1966 } 1967 byte_i_ref += 2; 1968 return old_cp_index; 1969 } 1970 PRAGMA_DIAG_POP 1971 1972 1973 // Rewrite constant pool references in the element_value portion of an 1974 // annotations_typeArray. This "structure" is from section 4.8.15.1 of 1975 // the 2nd-edition of the VM spec: 1976 // 1977 // struct element_value { 1978 // u1 tag; 1979 // union { 1980 // u2 const_value_index; 1981 // { 1982 // u2 type_name_index; 1983 // u2 const_name_index; 1984 // } enum_const_value; 1985 // u2 class_info_index; 1986 // annotation annotation_value; 1987 // struct { 1988 // u2 num_values; 1989 // element_value values[num_values]; 1990 // } array_value; 1991 // } value; 1992 // } 1993 // 1994 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value( 1995 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) { 1996 1997 if ((byte_i_ref + 1) > annotations_typeArray->length()) { 1998 // not enough room for a tag let alone the rest of an element_value 1999 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2000 ("length() is too small for a tag")); 2001 return false; 2002 } 2003 2004 u1 tag = annotations_typeArray->at(byte_i_ref); 2005 byte_i_ref++; 2006 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("tag='%c'", tag)); 2007 2008 switch (tag) { 2009 // These BaseType tag values are from Table 4.2 in VM spec: 2010 case 'B': // byte 2011 case 'C': // char 2012 case 'D': // double 2013 case 'F': // float 2014 case 'I': // int 2015 case 'J': // long 2016 case 'S': // short 2017 case 'Z': // boolean 2018 2019 // The remaining tag values are from Table 4.8 in the 2nd-edition of 2020 // the VM spec: 2021 case 's': 2022 { 2023 // For the above tag values (including the BaseType values), 2024 // value.const_value_index is right union field. 2025 2026 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2027 // not enough room for a const_value_index 2028 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2029 ("length() is too small for a const_value_index")); 2030 return false; 2031 } 2032 2033 u2 const_value_index = rewrite_cp_ref_in_annotation_data( 2034 annotations_typeArray, byte_i_ref, 2035 "mapped old const_value_index=%d", THREAD); 2036 2037 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2038 ("const_value_index=%d", const_value_index)); 2039 } break; 2040 2041 case 'e': 2042 { 2043 // for the above tag value, value.enum_const_value is right union field 2044 2045 if ((byte_i_ref + 4) > annotations_typeArray->length()) { 2046 // not enough room for a enum_const_value 2047 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2048 ("length() is too small for a enum_const_value")); 2049 return false; 2050 } 2051 2052 u2 type_name_index = rewrite_cp_ref_in_annotation_data( 2053 annotations_typeArray, byte_i_ref, 2054 "mapped old type_name_index=%d", THREAD); 2055 2056 u2 const_name_index = rewrite_cp_ref_in_annotation_data( 2057 annotations_typeArray, byte_i_ref, 2058 "mapped old const_name_index=%d", THREAD); 2059 2060 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2061 ("type_name_index=%d const_name_index=%d", type_name_index, 2062 const_name_index)); 2063 } break; 2064 2065 case 'c': 2066 { 2067 // for the above tag value, value.class_info_index is right union field 2068 2069 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2070 // not enough room for a class_info_index 2071 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2072 ("length() is too small for a class_info_index")); 2073 return false; 2074 } 2075 2076 u2 class_info_index = rewrite_cp_ref_in_annotation_data( 2077 annotations_typeArray, byte_i_ref, 2078 "mapped old class_info_index=%d", THREAD); 2079 2080 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2081 ("class_info_index=%d", class_info_index)); 2082 } break; 2083 2084 case '@': 2085 // For the above tag value, value.attr_value is the right union 2086 // field. This is a nested annotation. 2087 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, 2088 byte_i_ref, THREAD)) { 2089 // propagate failure back to caller 2090 return false; 2091 } 2092 break; 2093 2094 case '[': 2095 { 2096 if ((byte_i_ref + 2) > annotations_typeArray->length()) { 2097 // not enough room for a num_values field 2098 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2099 ("length() is too small for a num_values field")); 2100 return false; 2101 } 2102 2103 // For the above tag value, value.array_value is the right union 2104 // field. This is an array of nested element_value. 2105 u2 num_values = Bytes::get_Java_u2((address) 2106 annotations_typeArray->adr_at(byte_i_ref)); 2107 byte_i_ref += 2; 2108 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("num_values=%d", num_values)); 2109 2110 int calc_num_values = 0; 2111 for (; calc_num_values < num_values; calc_num_values++) { 2112 if (!rewrite_cp_refs_in_element_value( 2113 annotations_typeArray, byte_i_ref, THREAD)) { 2114 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2115 ("bad nested element_value at %d", calc_num_values)); 2116 // propagate failure back to caller 2117 return false; 2118 } 2119 } 2120 assert(num_values == calc_num_values, "sanity check"); 2121 } break; 2122 2123 default: 2124 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("bad tag=0x%x", tag)); 2125 return false; 2126 } // end decode tag field 2127 2128 return true; 2129 } // end rewrite_cp_refs_in_element_value() 2130 2131 2132 // Rewrite constant pool references in a fields_annotations field. 2133 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations( 2134 instanceKlassHandle scratch_class, TRAPS) { 2135 2136 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations(); 2137 2138 if (fields_annotations == NULL || fields_annotations->length() == 0) { 2139 // no fields_annotations so nothing to do 2140 return true; 2141 } 2142 2143 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2144 ("fields_annotations length=%d", fields_annotations->length())); 2145 2146 for (int i = 0; i < fields_annotations->length(); i++) { 2147 AnnotationArray* field_annotations = fields_annotations->at(i); 2148 if (field_annotations == NULL || field_annotations->length() == 0) { 2149 // this field does not have any annotations so skip it 2150 continue; 2151 } 2152 2153 int byte_i = 0; // byte index into field_annotations 2154 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i, 2155 THREAD)) { 2156 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2157 ("bad field_annotations at %d", i)); 2158 // propagate failure back to caller 2159 return false; 2160 } 2161 } 2162 2163 return true; 2164 } // end rewrite_cp_refs_in_fields_annotations() 2165 2166 2167 // Rewrite constant pool references in a methods_annotations field. 2168 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations( 2169 instanceKlassHandle scratch_class, TRAPS) { 2170 2171 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2172 Method* m = scratch_class->methods()->at(i); 2173 AnnotationArray* method_annotations = m->constMethod()->method_annotations(); 2174 2175 if (method_annotations == NULL || method_annotations->length() == 0) { 2176 // this method does not have any annotations so skip it 2177 continue; 2178 } 2179 2180 int byte_i = 0; // byte index into method_annotations 2181 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i, 2182 THREAD)) { 2183 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2184 ("bad method_annotations at %d", i)); 2185 // propagate failure back to caller 2186 return false; 2187 } 2188 } 2189 2190 return true; 2191 } // end rewrite_cp_refs_in_methods_annotations() 2192 2193 2194 // Rewrite constant pool references in a methods_parameter_annotations 2195 // field. This "structure" is adapted from the 2196 // RuntimeVisibleParameterAnnotations_attribute described in section 2197 // 4.8.17 of the 2nd-edition of the VM spec: 2198 // 2199 // methods_parameter_annotations_typeArray { 2200 // u1 num_parameters; 2201 // { 2202 // u2 num_annotations; 2203 // annotation annotations[num_annotations]; 2204 // } parameter_annotations[num_parameters]; 2205 // } 2206 // 2207 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations( 2208 instanceKlassHandle scratch_class, TRAPS) { 2209 2210 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2211 Method* m = scratch_class->methods()->at(i); 2212 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations(); 2213 if (method_parameter_annotations == NULL 2214 || method_parameter_annotations->length() == 0) { 2215 // this method does not have any parameter annotations so skip it 2216 continue; 2217 } 2218 2219 if (method_parameter_annotations->length() < 1) { 2220 // not enough room for a num_parameters field 2221 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2222 ("length() is too small for a num_parameters field at %d", i)); 2223 return false; 2224 } 2225 2226 int byte_i = 0; // byte index into method_parameter_annotations 2227 2228 u1 num_parameters = method_parameter_annotations->at(byte_i); 2229 byte_i++; 2230 2231 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2232 ("num_parameters=%d", num_parameters)); 2233 2234 int calc_num_parameters = 0; 2235 for (; calc_num_parameters < num_parameters; calc_num_parameters++) { 2236 if (!rewrite_cp_refs_in_annotations_typeArray( 2237 method_parameter_annotations, byte_i, THREAD)) { 2238 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2239 ("bad method_parameter_annotations at %d", calc_num_parameters)); 2240 // propagate failure back to caller 2241 return false; 2242 } 2243 } 2244 assert(num_parameters == calc_num_parameters, "sanity check"); 2245 } 2246 2247 return true; 2248 } // end rewrite_cp_refs_in_methods_parameter_annotations() 2249 2250 2251 // Rewrite constant pool references in a methods_default_annotations 2252 // field. This "structure" is adapted from the AnnotationDefault_attribute 2253 // that is described in section 4.8.19 of the 2nd-edition of the VM spec: 2254 // 2255 // methods_default_annotations_typeArray { 2256 // element_value default_value; 2257 // } 2258 // 2259 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations( 2260 instanceKlassHandle scratch_class, TRAPS) { 2261 2262 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2263 Method* m = scratch_class->methods()->at(i); 2264 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations(); 2265 if (method_default_annotations == NULL 2266 || method_default_annotations->length() == 0) { 2267 // this method does not have any default annotations so skip it 2268 continue; 2269 } 2270 2271 int byte_i = 0; // byte index into method_default_annotations 2272 2273 if (!rewrite_cp_refs_in_element_value( 2274 method_default_annotations, byte_i, THREAD)) { 2275 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2276 ("bad default element_value at %d", i)); 2277 // propagate failure back to caller 2278 return false; 2279 } 2280 } 2281 2282 return true; 2283 } // end rewrite_cp_refs_in_methods_default_annotations() 2284 2285 2286 // Rewrite constant pool references in a class_type_annotations field. 2287 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations( 2288 instanceKlassHandle scratch_class, TRAPS) { 2289 2290 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations(); 2291 if (class_type_annotations == NULL || class_type_annotations->length() == 0) { 2292 // no class_type_annotations so nothing to do 2293 return true; 2294 } 2295 2296 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2297 ("class_type_annotations length=%d", class_type_annotations->length())); 2298 2299 int byte_i = 0; // byte index into class_type_annotations 2300 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations, 2301 byte_i, "ClassFile", THREAD); 2302 } // end rewrite_cp_refs_in_class_type_annotations() 2303 2304 2305 // Rewrite constant pool references in a fields_type_annotations field. 2306 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations( 2307 instanceKlassHandle scratch_class, TRAPS) { 2308 2309 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations(); 2310 if (fields_type_annotations == NULL || fields_type_annotations->length() == 0) { 2311 // no fields_type_annotations so nothing to do 2312 return true; 2313 } 2314 2315 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2316 ("fields_type_annotations length=%d", fields_type_annotations->length())); 2317 2318 for (int i = 0; i < fields_type_annotations->length(); i++) { 2319 AnnotationArray* field_type_annotations = fields_type_annotations->at(i); 2320 if (field_type_annotations == NULL || field_type_annotations->length() == 0) { 2321 // this field does not have any annotations so skip it 2322 continue; 2323 } 2324 2325 int byte_i = 0; // byte index into field_type_annotations 2326 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations, 2327 byte_i, "field_info", THREAD)) { 2328 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2329 ("bad field_type_annotations at %d", i)); 2330 // propagate failure back to caller 2331 return false; 2332 } 2333 } 2334 2335 return true; 2336 } // end rewrite_cp_refs_in_fields_type_annotations() 2337 2338 2339 // Rewrite constant pool references in a methods_type_annotations field. 2340 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations( 2341 instanceKlassHandle scratch_class, TRAPS) { 2342 2343 for (int i = 0; i < scratch_class->methods()->length(); i++) { 2344 Method* m = scratch_class->methods()->at(i); 2345 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations(); 2346 2347 if (method_type_annotations == NULL || method_type_annotations->length() == 0) { 2348 // this method does not have any annotations so skip it 2349 continue; 2350 } 2351 2352 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2353 ("methods type_annotations length=%d", method_type_annotations->length())); 2354 2355 int byte_i = 0; // byte index into method_type_annotations 2356 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations, 2357 byte_i, "method_info", THREAD)) { 2358 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2359 ("bad method_type_annotations at %d", i)); 2360 // propagate failure back to caller 2361 return false; 2362 } 2363 } 2364 2365 return true; 2366 } // end rewrite_cp_refs_in_methods_type_annotations() 2367 2368 2369 // Rewrite constant pool references in a type_annotations 2370 // field. This "structure" is adapted from the 2371 // RuntimeVisibleTypeAnnotations_attribute described in 2372 // section 4.7.20 of the Java SE 8 Edition of the VM spec: 2373 // 2374 // type_annotations_typeArray { 2375 // u2 num_annotations; 2376 // type_annotation annotations[num_annotations]; 2377 // } 2378 // 2379 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray( 2380 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2381 const char * location_mesg, TRAPS) { 2382 2383 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2384 // not enough room for num_annotations field 2385 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2386 ("length() is too small for num_annotations field")); 2387 return false; 2388 } 2389 2390 u2 num_annotations = Bytes::get_Java_u2((address) 2391 type_annotations_typeArray->adr_at(byte_i_ref)); 2392 byte_i_ref += 2; 2393 2394 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2395 ("num_type_annotations=%d", num_annotations)); 2396 2397 int calc_num_annotations = 0; 2398 for (; calc_num_annotations < num_annotations; calc_num_annotations++) { 2399 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray, 2400 byte_i_ref, location_mesg, THREAD)) { 2401 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2402 ("bad type_annotation_struct at %d", calc_num_annotations)); 2403 // propagate failure back to caller 2404 return false; 2405 } 2406 } 2407 assert(num_annotations == calc_num_annotations, "sanity check"); 2408 2409 if (byte_i_ref != type_annotations_typeArray->length()) { 2410 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2411 ("read wrong amount of bytes at end of processing " 2412 "type_annotations_typeArray (%d of %d bytes were read)", 2413 byte_i_ref, type_annotations_typeArray->length())); 2414 return false; 2415 } 2416 2417 return true; 2418 } // end rewrite_cp_refs_in_type_annotations_typeArray() 2419 2420 2421 // Rewrite constant pool references in a type_annotation 2422 // field. This "structure" is adapted from the 2423 // RuntimeVisibleTypeAnnotations_attribute described in 2424 // section 4.7.20 of the Java SE 8 Edition of the VM spec: 2425 // 2426 // type_annotation { 2427 // u1 target_type; 2428 // union { 2429 // type_parameter_target; 2430 // supertype_target; 2431 // type_parameter_bound_target; 2432 // empty_target; 2433 // method_formal_parameter_target; 2434 // throws_target; 2435 // localvar_target; 2436 // catch_target; 2437 // offset_target; 2438 // type_argument_target; 2439 // } target_info; 2440 // type_path target_path; 2441 // annotation anno; 2442 // } 2443 // 2444 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct( 2445 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2446 const char * location_mesg, TRAPS) { 2447 2448 if (!skip_type_annotation_target(type_annotations_typeArray, 2449 byte_i_ref, location_mesg, THREAD)) { 2450 return false; 2451 } 2452 2453 if (!skip_type_annotation_type_path(type_annotations_typeArray, 2454 byte_i_ref, THREAD)) { 2455 return false; 2456 } 2457 2458 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray, 2459 byte_i_ref, THREAD)) { 2460 return false; 2461 } 2462 2463 return true; 2464 } // end rewrite_cp_refs_in_type_annotation_struct() 2465 2466 2467 // Read, verify and skip over the target_type and target_info part 2468 // so that rewriting can continue in the later parts of the struct. 2469 // 2470 // u1 target_type; 2471 // union { 2472 // type_parameter_target; 2473 // supertype_target; 2474 // type_parameter_bound_target; 2475 // empty_target; 2476 // method_formal_parameter_target; 2477 // throws_target; 2478 // localvar_target; 2479 // catch_target; 2480 // offset_target; 2481 // type_argument_target; 2482 // } target_info; 2483 // 2484 bool VM_RedefineClasses::skip_type_annotation_target( 2485 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, 2486 const char * location_mesg, TRAPS) { 2487 2488 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2489 // not enough room for a target_type let alone the rest of a type_annotation 2490 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2491 ("length() is too small for a target_type")); 2492 return false; 2493 } 2494 2495 u1 target_type = type_annotations_typeArray->at(byte_i_ref); 2496 byte_i_ref += 1; 2497 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("target_type=0x%.2x", target_type)); 2498 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("location=%s", location_mesg)); 2499 2500 // Skip over target_info 2501 switch (target_type) { 2502 case 0x00: 2503 // kind: type parameter declaration of generic class or interface 2504 // location: ClassFile 2505 case 0x01: 2506 // kind: type parameter declaration of generic method or constructor 2507 // location: method_info 2508 2509 { 2510 // struct: 2511 // type_parameter_target { 2512 // u1 type_parameter_index; 2513 // } 2514 // 2515 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2516 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2517 ("length() is too small for a type_parameter_target")); 2518 return false; 2519 } 2520 2521 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2522 byte_i_ref += 1; 2523 2524 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2525 ("type_parameter_target: type_parameter_index=%d", 2526 type_parameter_index)); 2527 } break; 2528 2529 case 0x10: 2530 // kind: type in extends clause of class or interface declaration 2531 // (including the direct superclass of an anonymous class declaration), 2532 // or in implements clause of interface declaration 2533 // location: ClassFile 2534 2535 { 2536 // struct: 2537 // supertype_target { 2538 // u2 supertype_index; 2539 // } 2540 // 2541 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2542 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2543 ("length() is too small for a supertype_target")); 2544 return false; 2545 } 2546 2547 u2 supertype_index = Bytes::get_Java_u2((address) 2548 type_annotations_typeArray->adr_at(byte_i_ref)); 2549 byte_i_ref += 2; 2550 2551 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2552 ("supertype_target: supertype_index=%d", supertype_index)); 2553 } break; 2554 2555 case 0x11: 2556 // kind: type in bound of type parameter declaration of generic class or interface 2557 // location: ClassFile 2558 case 0x12: 2559 // kind: type in bound of type parameter declaration of generic method or constructor 2560 // location: method_info 2561 2562 { 2563 // struct: 2564 // type_parameter_bound_target { 2565 // u1 type_parameter_index; 2566 // u1 bound_index; 2567 // } 2568 // 2569 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2570 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2571 ("length() is too small for a type_parameter_bound_target")); 2572 return false; 2573 } 2574 2575 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2576 byte_i_ref += 1; 2577 u1 bound_index = type_annotations_typeArray->at(byte_i_ref); 2578 byte_i_ref += 1; 2579 2580 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2581 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d", 2582 type_parameter_index, bound_index)); 2583 } break; 2584 2585 case 0x13: 2586 // kind: type in field declaration 2587 // location: field_info 2588 case 0x14: 2589 // kind: return type of method, or type of newly constructed object 2590 // location: method_info 2591 case 0x15: 2592 // kind: receiver type of method or constructor 2593 // location: method_info 2594 2595 { 2596 // struct: 2597 // empty_target { 2598 // } 2599 // 2600 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2601 ("empty_target")); 2602 } break; 2603 2604 case 0x16: 2605 // kind: type in formal parameter declaration of method, constructor, or lambda expression 2606 // location: method_info 2607 2608 { 2609 // struct: 2610 // formal_parameter_target { 2611 // u1 formal_parameter_index; 2612 // } 2613 // 2614 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2615 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2616 ("length() is too small for a formal_parameter_target")); 2617 return false; 2618 } 2619 2620 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref); 2621 byte_i_ref += 1; 2622 2623 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2624 ("formal_parameter_target: formal_parameter_index=%d", 2625 formal_parameter_index)); 2626 } break; 2627 2628 case 0x17: 2629 // kind: type in throws clause of method or constructor 2630 // location: method_info 2631 2632 { 2633 // struct: 2634 // throws_target { 2635 // u2 throws_type_index 2636 // } 2637 // 2638 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2639 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2640 ("length() is too small for a throws_target")); 2641 return false; 2642 } 2643 2644 u2 throws_type_index = Bytes::get_Java_u2((address) 2645 type_annotations_typeArray->adr_at(byte_i_ref)); 2646 byte_i_ref += 2; 2647 2648 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2649 ("throws_target: throws_type_index=%d", throws_type_index)); 2650 } break; 2651 2652 case 0x40: 2653 // kind: type in local variable declaration 2654 // location: Code 2655 case 0x41: 2656 // kind: type in resource variable declaration 2657 // location: Code 2658 2659 { 2660 // struct: 2661 // localvar_target { 2662 // u2 table_length; 2663 // struct { 2664 // u2 start_pc; 2665 // u2 length; 2666 // u2 index; 2667 // } table[table_length]; 2668 // } 2669 // 2670 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2671 // not enough room for a table_length let alone the rest of a localvar_target 2672 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2673 ("length() is too small for a localvar_target table_length")); 2674 return false; 2675 } 2676 2677 u2 table_length = Bytes::get_Java_u2((address) 2678 type_annotations_typeArray->adr_at(byte_i_ref)); 2679 byte_i_ref += 2; 2680 2681 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2682 ("localvar_target: table_length=%d", table_length)); 2683 2684 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry 2685 int table_size = table_length * table_struct_size; 2686 2687 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) { 2688 // not enough room for a table 2689 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2690 ("length() is too small for a table array of length %d", table_length)); 2691 return false; 2692 } 2693 2694 // Skip over table 2695 byte_i_ref += table_size; 2696 } break; 2697 2698 case 0x42: 2699 // kind: type in exception parameter declaration 2700 // location: Code 2701 2702 { 2703 // struct: 2704 // catch_target { 2705 // u2 exception_table_index; 2706 // } 2707 // 2708 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2709 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2710 ("length() is too small for a catch_target")); 2711 return false; 2712 } 2713 2714 u2 exception_table_index = Bytes::get_Java_u2((address) 2715 type_annotations_typeArray->adr_at(byte_i_ref)); 2716 byte_i_ref += 2; 2717 2718 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2719 ("catch_target: exception_table_index=%d", exception_table_index)); 2720 } break; 2721 2722 case 0x43: 2723 // kind: type in instanceof expression 2724 // location: Code 2725 case 0x44: 2726 // kind: type in new expression 2727 // location: Code 2728 case 0x45: 2729 // kind: type in method reference expression using ::new 2730 // location: Code 2731 case 0x46: 2732 // kind: type in method reference expression using ::Identifier 2733 // location: Code 2734 2735 { 2736 // struct: 2737 // offset_target { 2738 // u2 offset; 2739 // } 2740 // 2741 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { 2742 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2743 ("length() is too small for a offset_target")); 2744 return false; 2745 } 2746 2747 u2 offset = Bytes::get_Java_u2((address) 2748 type_annotations_typeArray->adr_at(byte_i_ref)); 2749 byte_i_ref += 2; 2750 2751 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2752 ("offset_target: offset=%d", offset)); 2753 } break; 2754 2755 case 0x47: 2756 // kind: type in cast expression 2757 // location: Code 2758 case 0x48: 2759 // kind: type argument for generic constructor in new expression or 2760 // explicit constructor invocation statement 2761 // location: Code 2762 case 0x49: 2763 // kind: type argument for generic method in method invocation expression 2764 // location: Code 2765 case 0x4A: 2766 // kind: type argument for generic constructor in method reference expression using ::new 2767 // location: Code 2768 case 0x4B: 2769 // kind: type argument for generic method in method reference expression using ::Identifier 2770 // location: Code 2771 2772 { 2773 // struct: 2774 // type_argument_target { 2775 // u2 offset; 2776 // u1 type_argument_index; 2777 // } 2778 // 2779 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) { 2780 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2781 ("length() is too small for a type_argument_target")); 2782 return false; 2783 } 2784 2785 u2 offset = Bytes::get_Java_u2((address) 2786 type_annotations_typeArray->adr_at(byte_i_ref)); 2787 byte_i_ref += 2; 2788 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref); 2789 byte_i_ref += 1; 2790 2791 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2792 ("type_argument_target: offset=%d, type_argument_index=%d", 2793 offset, type_argument_index)); 2794 } break; 2795 2796 default: 2797 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2798 ("unknown target_type")); 2799 #ifdef ASSERT 2800 ShouldNotReachHere(); 2801 #endif 2802 return false; 2803 } 2804 2805 return true; 2806 } // end skip_type_annotation_target() 2807 2808 2809 // Read, verify and skip over the type_path part so that rewriting 2810 // can continue in the later parts of the struct. 2811 // 2812 // type_path { 2813 // u1 path_length; 2814 // { 2815 // u1 type_path_kind; 2816 // u1 type_argument_index; 2817 // } path[path_length]; 2818 // } 2819 // 2820 bool VM_RedefineClasses::skip_type_annotation_type_path( 2821 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, TRAPS) { 2822 2823 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { 2824 // not enough room for a path_length let alone the rest of the type_path 2825 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2826 ("length() is too small for a type_path")); 2827 return false; 2828 } 2829 2830 u1 path_length = type_annotations_typeArray->at(byte_i_ref); 2831 byte_i_ref += 1; 2832 2833 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2834 ("type_path: path_length=%d", path_length)); 2835 2836 int calc_path_length = 0; 2837 for (; calc_path_length < path_length; calc_path_length++) { 2838 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) { 2839 // not enough room for a path 2840 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2841 ("length() is too small for path entry %d of %d", 2842 calc_path_length, path_length)); 2843 return false; 2844 } 2845 2846 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref); 2847 byte_i_ref += 1; 2848 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref); 2849 byte_i_ref += 1; 2850 2851 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2852 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d", 2853 calc_path_length, type_path_kind, type_argument_index)); 2854 2855 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) { 2856 // not enough room for a path 2857 RC_TRACE_WITH_THREAD(0x02000000, THREAD, 2858 ("inconsistent type_path values")); 2859 return false; 2860 } 2861 } 2862 assert(path_length == calc_path_length, "sanity check"); 2863 2864 return true; 2865 } // end skip_type_annotation_type_path() 2866 2867 2868 // Rewrite constant pool references in the method's stackmap table. 2869 // These "structures" are adapted from the StackMapTable_attribute that 2870 // is described in section 4.8.4 of the 6.0 version of the VM spec 2871 // (dated 2005.10.26): 2872 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf 2873 // 2874 // stack_map { 2875 // u2 number_of_entries; 2876 // stack_map_frame entries[number_of_entries]; 2877 // } 2878 // 2879 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table( 2880 methodHandle method, TRAPS) { 2881 2882 if (!method->has_stackmap_table()) { 2883 return; 2884 } 2885 2886 AnnotationArray* stackmap_data = method->stackmap_data(); 2887 address stackmap_p = (address)stackmap_data->adr_at(0); 2888 address stackmap_end = stackmap_p + stackmap_data->length(); 2889 2890 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries"); 2891 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p); 2892 stackmap_p += 2; 2893 2894 RC_TRACE_WITH_THREAD(0x04000000, THREAD, 2895 ("number_of_entries=%u", number_of_entries)); 2896 2897 // walk through each stack_map_frame 2898 u2 calc_number_of_entries = 0; 2899 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) { 2900 // The stack_map_frame structure is a u1 frame_type followed by 2901 // 0 or more bytes of data: 2902 // 2903 // union stack_map_frame { 2904 // same_frame; 2905 // same_locals_1_stack_item_frame; 2906 // same_locals_1_stack_item_frame_extended; 2907 // chop_frame; 2908 // same_frame_extended; 2909 // append_frame; 2910 // full_frame; 2911 // } 2912 2913 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type"); 2914 // The Linux compiler does not like frame_type to be u1 or u2. It 2915 // issues the following warning for the first if-statement below: 2916 // 2917 // "warning: comparison is always true due to limited range of data type" 2918 // 2919 u4 frame_type = *stackmap_p; 2920 stackmap_p++; 2921 2922 // same_frame { 2923 // u1 frame_type = SAME; /* 0-63 */ 2924 // } 2925 if (frame_type >= 0 && frame_type <= 63) { 2926 // nothing more to do for same_frame 2927 } 2928 2929 // same_locals_1_stack_item_frame { 2930 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */ 2931 // verification_type_info stack[1]; 2932 // } 2933 else if (frame_type >= 64 && frame_type <= 127) { 2934 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2935 calc_number_of_entries, frame_type, THREAD); 2936 } 2937 2938 // reserved for future use 2939 else if (frame_type >= 128 && frame_type <= 246) { 2940 // nothing more to do for reserved frame_types 2941 } 2942 2943 // same_locals_1_stack_item_frame_extended { 2944 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */ 2945 // u2 offset_delta; 2946 // verification_type_info stack[1]; 2947 // } 2948 else if (frame_type == 247) { 2949 stackmap_p += 2; 2950 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2951 calc_number_of_entries, frame_type, THREAD); 2952 } 2953 2954 // chop_frame { 2955 // u1 frame_type = CHOP; /* 248-250 */ 2956 // u2 offset_delta; 2957 // } 2958 else if (frame_type >= 248 && frame_type <= 250) { 2959 stackmap_p += 2; 2960 } 2961 2962 // same_frame_extended { 2963 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/ 2964 // u2 offset_delta; 2965 // } 2966 else if (frame_type == 251) { 2967 stackmap_p += 2; 2968 } 2969 2970 // append_frame { 2971 // u1 frame_type = APPEND; /* 252-254 */ 2972 // u2 offset_delta; 2973 // verification_type_info locals[frame_type - 251]; 2974 // } 2975 else if (frame_type >= 252 && frame_type <= 254) { 2976 assert(stackmap_p + 2 <= stackmap_end, 2977 "no room for offset_delta"); 2978 stackmap_p += 2; 2979 u1 len = frame_type - 251; 2980 for (u1 i = 0; i < len; i++) { 2981 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 2982 calc_number_of_entries, frame_type, THREAD); 2983 } 2984 } 2985 2986 // full_frame { 2987 // u1 frame_type = FULL_FRAME; /* 255 */ 2988 // u2 offset_delta; 2989 // u2 number_of_locals; 2990 // verification_type_info locals[number_of_locals]; 2991 // u2 number_of_stack_items; 2992 // verification_type_info stack[number_of_stack_items]; 2993 // } 2994 else if (frame_type == 255) { 2995 assert(stackmap_p + 2 + 2 <= stackmap_end, 2996 "no room for smallest full_frame"); 2997 stackmap_p += 2; 2998 2999 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p); 3000 stackmap_p += 2; 3001 3002 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) { 3003 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3004 calc_number_of_entries, frame_type, THREAD); 3005 } 3006 3007 // Use the largest size for the number_of_stack_items, but only get 3008 // the right number of bytes. 3009 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p); 3010 stackmap_p += 2; 3011 3012 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) { 3013 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, 3014 calc_number_of_entries, frame_type, THREAD); 3015 } 3016 } 3017 } // end while there is a stack_map_frame 3018 assert(number_of_entries == calc_number_of_entries, "sanity check"); 3019 } // end rewrite_cp_refs_in_stack_map_table() 3020 3021 3022 // Rewrite constant pool references in the verification type info 3023 // portion of the method's stackmap table. These "structures" are 3024 // adapted from the StackMapTable_attribute that is described in 3025 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26): 3026 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf 3027 // 3028 // The verification_type_info structure is a u1 tag followed by 0 or 3029 // more bytes of data: 3030 // 3031 // union verification_type_info { 3032 // Top_variable_info; 3033 // Integer_variable_info; 3034 // Float_variable_info; 3035 // Long_variable_info; 3036 // Double_variable_info; 3037 // Null_variable_info; 3038 // UninitializedThis_variable_info; 3039 // Object_variable_info; 3040 // Uninitialized_variable_info; 3041 // } 3042 // 3043 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info( 3044 address& stackmap_p_ref, address stackmap_end, u2 frame_i, 3045 u1 frame_type, TRAPS) { 3046 3047 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag"); 3048 u1 tag = *stackmap_p_ref; 3049 stackmap_p_ref++; 3050 3051 switch (tag) { 3052 // Top_variable_info { 3053 // u1 tag = ITEM_Top; /* 0 */ 3054 // } 3055 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top 3056 case 0: // fall through 3057 3058 // Integer_variable_info { 3059 // u1 tag = ITEM_Integer; /* 1 */ 3060 // } 3061 case ITEM_Integer: // fall through 3062 3063 // Float_variable_info { 3064 // u1 tag = ITEM_Float; /* 2 */ 3065 // } 3066 case ITEM_Float: // fall through 3067 3068 // Double_variable_info { 3069 // u1 tag = ITEM_Double; /* 3 */ 3070 // } 3071 case ITEM_Double: // fall through 3072 3073 // Long_variable_info { 3074 // u1 tag = ITEM_Long; /* 4 */ 3075 // } 3076 case ITEM_Long: // fall through 3077 3078 // Null_variable_info { 3079 // u1 tag = ITEM_Null; /* 5 */ 3080 // } 3081 case ITEM_Null: // fall through 3082 3083 // UninitializedThis_variable_info { 3084 // u1 tag = ITEM_UninitializedThis; /* 6 */ 3085 // } 3086 case ITEM_UninitializedThis: 3087 // nothing more to do for the above tag types 3088 break; 3089 3090 // Object_variable_info { 3091 // u1 tag = ITEM_Object; /* 7 */ 3092 // u2 cpool_index; 3093 // } 3094 case ITEM_Object: 3095 { 3096 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index"); 3097 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref); 3098 u2 new_cp_index = find_new_index(cpool_index); 3099 if (new_cp_index != 0) { 3100 RC_TRACE_WITH_THREAD(0x04000000, THREAD, 3101 ("mapped old cpool_index=%d", cpool_index)); 3102 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index); 3103 cpool_index = new_cp_index; 3104 } 3105 stackmap_p_ref += 2; 3106 3107 RC_TRACE_WITH_THREAD(0x04000000, THREAD, 3108 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i, 3109 frame_type, cpool_index)); 3110 } break; 3111 3112 // Uninitialized_variable_info { 3113 // u1 tag = ITEM_Uninitialized; /* 8 */ 3114 // u2 offset; 3115 // } 3116 case ITEM_Uninitialized: 3117 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset"); 3118 stackmap_p_ref += 2; 3119 break; 3120 3121 default: 3122 RC_TRACE_WITH_THREAD(0x04000000, THREAD, 3123 ("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag)); 3124 ShouldNotReachHere(); 3125 break; 3126 } // end switch (tag) 3127 } // end rewrite_cp_refs_in_verification_type_info() 3128 3129 3130 // Change the constant pool associated with klass scratch_class to 3131 // scratch_cp. If shrink is true, then scratch_cp_length elements 3132 // are copied from scratch_cp to a smaller constant pool and the 3133 // smaller constant pool is associated with scratch_class. 3134 void VM_RedefineClasses::set_new_constant_pool( 3135 ClassLoaderData* loader_data, 3136 instanceKlassHandle scratch_class, constantPoolHandle scratch_cp, 3137 int scratch_cp_length, TRAPS) { 3138 assert(scratch_cp->length() >= scratch_cp_length, "sanity check"); 3139 3140 // scratch_cp is a merged constant pool and has enough space for a 3141 // worst case merge situation. We want to associate the minimum 3142 // sized constant pool with the klass to save space. 3143 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK); 3144 constantPoolHandle smaller_cp(THREAD, cp); 3145 3146 // preserve version() value in the smaller copy 3147 int version = scratch_cp->version(); 3148 assert(version != 0, "sanity check"); 3149 smaller_cp->set_version(version); 3150 3151 // attach klass to new constant pool 3152 // reference to the cp holder is needed for copy_operands() 3153 smaller_cp->set_pool_holder(scratch_class()); 3154 3155 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD); 3156 if (HAS_PENDING_EXCEPTION) { 3157 // Exception is handled in the caller 3158 loader_data->add_to_deallocate_list(smaller_cp()); 3159 return; 3160 } 3161 scratch_cp = smaller_cp; 3162 3163 // attach new constant pool to klass 3164 scratch_class->set_constants(scratch_cp()); 3165 3166 int i; // for portability 3167 3168 // update each field in klass to use new constant pool indices as needed 3169 for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) { 3170 jshort cur_index = fs.name_index(); 3171 jshort new_index = find_new_index(cur_index); 3172 if (new_index != 0) { 3173 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3174 ("field-name_index change: %d to %d", cur_index, new_index)); 3175 fs.set_name_index(new_index); 3176 } 3177 cur_index = fs.signature_index(); 3178 new_index = find_new_index(cur_index); 3179 if (new_index != 0) { 3180 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3181 ("field-signature_index change: %d to %d", cur_index, new_index)); 3182 fs.set_signature_index(new_index); 3183 } 3184 cur_index = fs.initval_index(); 3185 new_index = find_new_index(cur_index); 3186 if (new_index != 0) { 3187 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3188 ("field-initval_index change: %d to %d", cur_index, new_index)); 3189 fs.set_initval_index(new_index); 3190 } 3191 cur_index = fs.generic_signature_index(); 3192 new_index = find_new_index(cur_index); 3193 if (new_index != 0) { 3194 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3195 ("field-generic_signature change: %d to %d", cur_index, new_index)); 3196 fs.set_generic_signature_index(new_index); 3197 } 3198 } // end for each field 3199 3200 // Update constant pool indices in the inner classes info to use 3201 // new constant indices as needed. The inner classes info is a 3202 // quadruple: 3203 // (inner_class_info, outer_class_info, inner_name, inner_access_flags) 3204 InnerClassesIterator iter(scratch_class); 3205 for (; !iter.done(); iter.next()) { 3206 int cur_index = iter.inner_class_info_index(); 3207 if (cur_index == 0) { 3208 continue; // JVM spec. allows null inner class refs so skip it 3209 } 3210 int new_index = find_new_index(cur_index); 3211 if (new_index != 0) { 3212 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3213 ("inner_class_info change: %d to %d", cur_index, new_index)); 3214 iter.set_inner_class_info_index(new_index); 3215 } 3216 cur_index = iter.outer_class_info_index(); 3217 new_index = find_new_index(cur_index); 3218 if (new_index != 0) { 3219 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3220 ("outer_class_info change: %d to %d", cur_index, new_index)); 3221 iter.set_outer_class_info_index(new_index); 3222 } 3223 cur_index = iter.inner_name_index(); 3224 new_index = find_new_index(cur_index); 3225 if (new_index != 0) { 3226 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3227 ("inner_name change: %d to %d", cur_index, new_index)); 3228 iter.set_inner_name_index(new_index); 3229 } 3230 } // end for each inner class 3231 3232 // Attach each method in klass to the new constant pool and update 3233 // to use new constant pool indices as needed: 3234 Array<Method*>* methods = scratch_class->methods(); 3235 for (i = methods->length() - 1; i >= 0; i--) { 3236 methodHandle method(THREAD, methods->at(i)); 3237 method->set_constants(scratch_cp()); 3238 3239 int new_index = find_new_index(method->name_index()); 3240 if (new_index != 0) { 3241 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3242 ("method-name_index change: %d to %d", method->name_index(), 3243 new_index)); 3244 method->set_name_index(new_index); 3245 } 3246 new_index = find_new_index(method->signature_index()); 3247 if (new_index != 0) { 3248 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3249 ("method-signature_index change: %d to %d", 3250 method->signature_index(), new_index)); 3251 method->set_signature_index(new_index); 3252 } 3253 new_index = find_new_index(method->generic_signature_index()); 3254 if (new_index != 0) { 3255 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3256 ("method-generic_signature_index change: %d to %d", 3257 method->generic_signature_index(), new_index)); 3258 method->set_generic_signature_index(new_index); 3259 } 3260 3261 // Update constant pool indices in the method's checked exception 3262 // table to use new constant indices as needed. 3263 int cext_length = method->checked_exceptions_length(); 3264 if (cext_length > 0) { 3265 CheckedExceptionElement * cext_table = 3266 method->checked_exceptions_start(); 3267 for (int j = 0; j < cext_length; j++) { 3268 int cur_index = cext_table[j].class_cp_index; 3269 int new_index = find_new_index(cur_index); 3270 if (new_index != 0) { 3271 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3272 ("cext-class_cp_index change: %d to %d", cur_index, new_index)); 3273 cext_table[j].class_cp_index = (u2)new_index; 3274 } 3275 } // end for each checked exception table entry 3276 } // end if there are checked exception table entries 3277 3278 // Update each catch type index in the method's exception table 3279 // to use new constant pool indices as needed. The exception table 3280 // holds quadruple entries of the form: 3281 // (beg_bci, end_bci, handler_bci, klass_index) 3282 3283 ExceptionTable ex_table(method()); 3284 int ext_length = ex_table.length(); 3285 3286 for (int j = 0; j < ext_length; j ++) { 3287 int cur_index = ex_table.catch_type_index(j); 3288 int new_index = find_new_index(cur_index); 3289 if (new_index != 0) { 3290 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3291 ("ext-klass_index change: %d to %d", cur_index, new_index)); 3292 ex_table.set_catch_type_index(j, new_index); 3293 } 3294 } // end for each exception table entry 3295 3296 // Update constant pool indices in the method's local variable 3297 // table to use new constant indices as needed. The local variable 3298 // table hold sextuple entries of the form: 3299 // (start_pc, length, name_index, descriptor_index, signature_index, slot) 3300 int lvt_length = method->localvariable_table_length(); 3301 if (lvt_length > 0) { 3302 LocalVariableTableElement * lv_table = 3303 method->localvariable_table_start(); 3304 for (int j = 0; j < lvt_length; j++) { 3305 int cur_index = lv_table[j].name_cp_index; 3306 int new_index = find_new_index(cur_index); 3307 if (new_index != 0) { 3308 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3309 ("lvt-name_cp_index change: %d to %d", cur_index, new_index)); 3310 lv_table[j].name_cp_index = (u2)new_index; 3311 } 3312 cur_index = lv_table[j].descriptor_cp_index; 3313 new_index = find_new_index(cur_index); 3314 if (new_index != 0) { 3315 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3316 ("lvt-descriptor_cp_index change: %d to %d", cur_index, 3317 new_index)); 3318 lv_table[j].descriptor_cp_index = (u2)new_index; 3319 } 3320 cur_index = lv_table[j].signature_cp_index; 3321 new_index = find_new_index(cur_index); 3322 if (new_index != 0) { 3323 RC_TRACE_WITH_THREAD(0x00080000, THREAD, 3324 ("lvt-signature_cp_index change: %d to %d", cur_index, new_index)); 3325 lv_table[j].signature_cp_index = (u2)new_index; 3326 } 3327 } // end for each local variable table entry 3328 } // end if there are local variable table entries 3329 3330 rewrite_cp_refs_in_stack_map_table(method, THREAD); 3331 } // end for each method 3332 } // end set_new_constant_pool() 3333 3334 3335 // Unevolving classes may point to methods of the_class directly 3336 // from their constant pool caches, itables, and/or vtables. We 3337 // use the ClassLoaderDataGraph::classes_do() facility and this helper 3338 // to fix up these pointers. 3339 3340 // Adjust cpools and vtables closure 3341 void VM_RedefineClasses::AdjustCpoolCacheAndVtable::do_klass(Klass* k) { 3342 3343 // This is a very busy routine. We don't want too much tracing 3344 // printed out. 3345 bool trace_name_printed = false; 3346 InstanceKlass *the_class = InstanceKlass::cast(_the_class_oop); 3347 3348 // Very noisy: only enable this call if you are trying to determine 3349 // that a specific class gets found by this routine. 3350 // RC_TRACE macro has an embedded ResourceMark 3351 // RC_TRACE_WITH_THREAD(0x00100000, THREAD, 3352 // ("adjust check: name=%s", k->external_name())); 3353 // trace_name_printed = true; 3354 3355 // If the class being redefined is java.lang.Object, we need to fix all 3356 // array class vtables also 3357 if (k->oop_is_array() && _the_class_oop == SystemDictionary::Object_klass()) { 3358 k->vtable()->adjust_method_entries(the_class, &trace_name_printed); 3359 3360 } else if (k->oop_is_instance()) { 3361 HandleMark hm(_thread); 3362 InstanceKlass *ik = InstanceKlass::cast(k); 3363 3364 // HotSpot specific optimization! HotSpot does not currently 3365 // support delegation from the bootstrap class loader to a 3366 // user-defined class loader. This means that if the bootstrap 3367 // class loader is the initiating class loader, then it will also 3368 // be the defining class loader. This also means that classes 3369 // loaded by the bootstrap class loader cannot refer to classes 3370 // loaded by a user-defined class loader. Note: a user-defined 3371 // class loader can delegate to the bootstrap class loader. 3372 // 3373 // If the current class being redefined has a user-defined class 3374 // loader as its defining class loader, then we can skip all 3375 // classes loaded by the bootstrap class loader. 3376 bool is_user_defined = 3377 InstanceKlass::cast(_the_class_oop)->class_loader() != NULL; 3378 if (is_user_defined && ik->class_loader() == NULL) { 3379 return; 3380 } 3381 3382 // Fix the vtable embedded in the_class and subclasses of the_class, 3383 // if one exists. We discard scratch_class and we don't keep an 3384 // InstanceKlass around to hold obsolete methods so we don't have 3385 // any other InstanceKlass embedded vtables to update. The vtable 3386 // holds the Method*s for virtual (but not final) methods. 3387 // Default methods, or concrete methods in interfaces are stored 3388 // in the vtable, so if an interface changes we need to check 3389 // adjust_method_entries() for every InstanceKlass, which will also 3390 // adjust the default method vtable indices. 3391 // We also need to adjust any default method entries that are 3392 // not yet in the vtable, because the vtable setup is in progress. 3393 // This must be done after we adjust the default_methods and 3394 // default_vtable_indices for methods already in the vtable. 3395 // If redefining Unsafe, walk all the vtables looking for entries. 3396 if (ik->vtable_length() > 0 && (_the_class_oop->is_interface() 3397 || _the_class_oop == SystemDictionary::misc_Unsafe_klass() 3398 || ik->is_subtype_of(_the_class_oop))) { 3399 // ik->vtable() creates a wrapper object; rm cleans it up 3400 ResourceMark rm(_thread); 3401 3402 ik->vtable()->adjust_method_entries(the_class, &trace_name_printed); 3403 ik->adjust_default_methods(the_class, &trace_name_printed); 3404 } 3405 3406 // If the current class has an itable and we are either redefining an 3407 // interface or if the current class is a subclass of the_class, then 3408 // we potentially have to fix the itable. If we are redefining an 3409 // interface, then we have to call adjust_method_entries() for 3410 // every InstanceKlass that has an itable since there isn't a 3411 // subclass relationship between an interface and an InstanceKlass. 3412 // If redefining Unsafe, walk all the itables looking for entries. 3413 if (ik->itable_length() > 0 && (_the_class_oop->is_interface() 3414 || _the_class_oop == SystemDictionary::misc_Unsafe_klass() 3415 || ik->is_subclass_of(_the_class_oop))) { 3416 // ik->itable() creates a wrapper object; rm cleans it up 3417 ResourceMark rm(_thread); 3418 3419 ik->itable()->adjust_method_entries(the_class, &trace_name_printed); 3420 } 3421 3422 // The constant pools in other classes (other_cp) can refer to 3423 // methods in the_class. We have to update method information in 3424 // other_cp's cache. If other_cp has a previous version, then we 3425 // have to repeat the process for each previous version. The 3426 // constant pool cache holds the Method*s for non-virtual 3427 // methods and for virtual, final methods. 3428 // 3429 // Special case: if the current class is the_class, then new_cp 3430 // has already been attached to the_class and old_cp has already 3431 // been added as a previous version. The new_cp doesn't have any 3432 // cached references to old methods so it doesn't need to be 3433 // updated. We can simply start with the previous version(s) in 3434 // that case. 3435 constantPoolHandle other_cp; 3436 ConstantPoolCache* cp_cache; 3437 3438 if (ik != _the_class_oop) { 3439 // this klass' constant pool cache may need adjustment 3440 other_cp = constantPoolHandle(ik->constants()); 3441 cp_cache = other_cp->cache(); 3442 if (cp_cache != NULL) { 3443 cp_cache->adjust_method_entries(the_class, &trace_name_printed); 3444 } 3445 } 3446 3447 // the previous versions' constant pool caches may need adjustment 3448 for (InstanceKlass* pv_node = ik->previous_versions(); 3449 pv_node != NULL; 3450 pv_node = pv_node->previous_versions()) { 3451 cp_cache = pv_node->constants()->cache(); 3452 if (cp_cache != NULL) { 3453 cp_cache->adjust_method_entries(pv_node, &trace_name_printed); 3454 } 3455 } 3456 } 3457 } 3458 3459 void VM_RedefineClasses::update_jmethod_ids() { 3460 for (int j = 0; j < _matching_methods_length; ++j) { 3461 Method* old_method = _matching_old_methods[j]; 3462 jmethodID jmid = old_method->find_jmethod_id_or_null(); 3463 if (jmid != NULL) { 3464 // There is a jmethodID, change it to point to the new method 3465 methodHandle new_method_h(_matching_new_methods[j]); 3466 Method::change_method_associated_with_jmethod_id(jmid, new_method_h()); 3467 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j], 3468 "should be replaced"); 3469 } 3470 } 3471 } 3472 3473 int VM_RedefineClasses::check_methods_and_mark_as_obsolete() { 3474 int emcp_method_count = 0; 3475 int obsolete_count = 0; 3476 int old_index = 0; 3477 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) { 3478 Method* old_method = _matching_old_methods[j]; 3479 Method* new_method = _matching_new_methods[j]; 3480 Method* old_array_method; 3481 3482 // Maintain an old_index into the _old_methods array by skipping 3483 // deleted methods 3484 while ((old_array_method = _old_methods->at(old_index)) != old_method) { 3485 ++old_index; 3486 } 3487 3488 if (MethodComparator::methods_EMCP(old_method, new_method)) { 3489 // The EMCP definition from JSR-163 requires the bytecodes to be 3490 // the same with the exception of constant pool indices which may 3491 // differ. However, the constants referred to by those indices 3492 // must be the same. 3493 // 3494 // We use methods_EMCP() for comparison since constant pool 3495 // merging can remove duplicate constant pool entries that were 3496 // present in the old method and removed from the rewritten new 3497 // method. A faster binary comparison function would consider the 3498 // old and new methods to be different when they are actually 3499 // EMCP. 3500 // 3501 // The old and new methods are EMCP and you would think that we 3502 // could get rid of one of them here and now and save some space. 3503 // However, the concept of EMCP only considers the bytecodes and 3504 // the constant pool entries in the comparison. Other things, 3505 // e.g., the line number table (LNT) or the local variable table 3506 // (LVT) don't count in the comparison. So the new (and EMCP) 3507 // method can have a new LNT that we need so we can't just 3508 // overwrite the new method with the old method. 3509 // 3510 // When this routine is called, we have already attached the new 3511 // methods to the_class so the old methods are effectively 3512 // overwritten. However, if an old method is still executing, 3513 // then the old method cannot be collected until sometime after 3514 // the old method call has returned. So the overwriting of old 3515 // methods by new methods will save us space except for those 3516 // (hopefully few) old methods that are still executing. 3517 // 3518 // A method refers to a ConstMethod* and this presents another 3519 // possible avenue to space savings. The ConstMethod* in the 3520 // new method contains possibly new attributes (LNT, LVT, etc). 3521 // At first glance, it seems possible to save space by replacing 3522 // the ConstMethod* in the old method with the ConstMethod* 3523 // from the new method. The old and new methods would share the 3524 // same ConstMethod* and we would save the space occupied by 3525 // the old ConstMethod*. However, the ConstMethod* contains 3526 // a back reference to the containing method. Sharing the 3527 // ConstMethod* between two methods could lead to confusion in 3528 // the code that uses the back reference. This would lead to 3529 // brittle code that could be broken in non-obvious ways now or 3530 // in the future. 3531 // 3532 // Another possibility is to copy the ConstMethod* from the new 3533 // method to the old method and then overwrite the new method with 3534 // the old method. Since the ConstMethod* contains the bytecodes 3535 // for the method embedded in the oop, this option would change 3536 // the bytecodes out from under any threads executing the old 3537 // method and make the thread's bcp invalid. Since EMCP requires 3538 // that the bytecodes be the same modulo constant pool indices, it 3539 // is straight forward to compute the correct new bcp in the new 3540 // ConstMethod* from the old bcp in the old ConstMethod*. The 3541 // time consuming part would be searching all the frames in all 3542 // of the threads to find all of the calls to the old method. 3543 // 3544 // It looks like we will have to live with the limited savings 3545 // that we get from effectively overwriting the old methods 3546 // when the new methods are attached to the_class. 3547 3548 // Count number of methods that are EMCP. The method will be marked 3549 // old but not obsolete if it is EMCP. 3550 emcp_method_count++; 3551 3552 // An EMCP method is _not_ obsolete. An obsolete method has a 3553 // different jmethodID than the current method. An EMCP method 3554 // has the same jmethodID as the current method. Having the 3555 // same jmethodID for all EMCP versions of a method allows for 3556 // a consistent view of the EMCP methods regardless of which 3557 // EMCP method you happen to have in hand. For example, a 3558 // breakpoint set in one EMCP method will work for all EMCP 3559 // versions of the method including the current one. 3560 } else { 3561 // mark obsolete methods as such 3562 old_method->set_is_obsolete(); 3563 obsolete_count++; 3564 3565 // obsolete methods need a unique idnum so they become new entries in 3566 // the jmethodID cache in InstanceKlass 3567 assert(old_method->method_idnum() == new_method->method_idnum(), "must match"); 3568 u2 num = InstanceKlass::cast(_the_class_oop)->next_method_idnum(); 3569 if (num != ConstMethod::UNSET_IDNUM) { 3570 old_method->set_method_idnum(num); 3571 } 3572 3573 // With tracing we try not to "yack" too much. The position of 3574 // this trace assumes there are fewer obsolete methods than 3575 // EMCP methods. 3576 RC_TRACE(0x00000100, ("mark %s(%s) as obsolete", 3577 old_method->name()->as_C_string(), 3578 old_method->signature()->as_C_string())); 3579 } 3580 old_method->set_is_old(); 3581 } 3582 for (int i = 0; i < _deleted_methods_length; ++i) { 3583 Method* old_method = _deleted_methods[i]; 3584 3585 assert(!old_method->has_vtable_index(), 3586 "cannot delete methods with vtable entries");; 3587 3588 // Mark all deleted methods as old, obsolete and deleted 3589 old_method->set_is_deleted(); 3590 old_method->set_is_old(); 3591 old_method->set_is_obsolete(); 3592 ++obsolete_count; 3593 // With tracing we try not to "yack" too much. The position of 3594 // this trace assumes there are fewer obsolete methods than 3595 // EMCP methods. 3596 RC_TRACE(0x00000100, ("mark deleted %s(%s) as obsolete", 3597 old_method->name()->as_C_string(), 3598 old_method->signature()->as_C_string())); 3599 } 3600 assert((emcp_method_count + obsolete_count) == _old_methods->length(), 3601 "sanity check"); 3602 RC_TRACE(0x00000100, ("EMCP_cnt=%d, obsolete_cnt=%d", emcp_method_count, 3603 obsolete_count)); 3604 return emcp_method_count; 3605 } 3606 3607 // This internal class transfers the native function registration from old methods 3608 // to new methods. It is designed to handle both the simple case of unchanged 3609 // native methods and the complex cases of native method prefixes being added and/or 3610 // removed. 3611 // It expects only to be used during the VM_RedefineClasses op (a safepoint). 3612 // 3613 // This class is used after the new methods have been installed in "the_class". 3614 // 3615 // So, for example, the following must be handled. Where 'm' is a method and 3616 // a number followed by an underscore is a prefix. 3617 // 3618 // Old Name New Name 3619 // Simple transfer to new method m -> m 3620 // Add prefix m -> 1_m 3621 // Remove prefix 1_m -> m 3622 // Simultaneous add of prefixes m -> 3_2_1_m 3623 // Simultaneous removal of prefixes 3_2_1_m -> m 3624 // Simultaneous add and remove 1_m -> 2_m 3625 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m 3626 // 3627 class TransferNativeFunctionRegistration { 3628 private: 3629 instanceKlassHandle the_class; 3630 int prefix_count; 3631 char** prefixes; 3632 3633 // Recursively search the binary tree of possibly prefixed method names. 3634 // Iteration could be used if all agents were well behaved. Full tree walk is 3635 // more resilent to agents not cleaning up intermediate methods. 3636 // Branch at each depth in the binary tree is: 3637 // (1) without the prefix. 3638 // (2) with the prefix. 3639 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...) 3640 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len, 3641 Symbol* signature) { 3642 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len); 3643 if (name_symbol != NULL) { 3644 Method* method = the_class()->lookup_method(name_symbol, signature); 3645 if (method != NULL) { 3646 // Even if prefixed, intermediate methods must exist. 3647 if (method->is_native()) { 3648 // Wahoo, we found a (possibly prefixed) version of the method, return it. 3649 return method; 3650 } 3651 if (depth < prefix_count) { 3652 // Try applying further prefixes (other than this one). 3653 method = search_prefix_name_space(depth+1, name_str, name_len, signature); 3654 if (method != NULL) { 3655 return method; // found 3656 } 3657 3658 // Try adding this prefix to the method name and see if it matches 3659 // another method name. 3660 char* prefix = prefixes[depth]; 3661 size_t prefix_len = strlen(prefix); 3662 size_t trial_len = name_len + prefix_len; 3663 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1); 3664 strcpy(trial_name_str, prefix); 3665 strcat(trial_name_str, name_str); 3666 method = search_prefix_name_space(depth+1, trial_name_str, trial_len, 3667 signature); 3668 if (method != NULL) { 3669 // If found along this branch, it was prefixed, mark as such 3670 method->set_is_prefixed_native(); 3671 return method; // found 3672 } 3673 } 3674 } 3675 } 3676 return NULL; // This whole branch bore nothing 3677 } 3678 3679 // Return the method name with old prefixes stripped away. 3680 char* method_name_without_prefixes(Method* method) { 3681 Symbol* name = method->name(); 3682 char* name_str = name->as_utf8(); 3683 3684 // Old prefixing may be defunct, strip prefixes, if any. 3685 for (int i = prefix_count-1; i >= 0; i--) { 3686 char* prefix = prefixes[i]; 3687 size_t prefix_len = strlen(prefix); 3688 if (strncmp(prefix, name_str, prefix_len) == 0) { 3689 name_str += prefix_len; 3690 } 3691 } 3692 return name_str; 3693 } 3694 3695 // Strip any prefixes off the old native method, then try to find a 3696 // (possibly prefixed) new native that matches it. 3697 Method* strip_and_search_for_new_native(Method* method) { 3698 ResourceMark rm; 3699 char* name_str = method_name_without_prefixes(method); 3700 return search_prefix_name_space(0, name_str, strlen(name_str), 3701 method->signature()); 3702 } 3703 3704 public: 3705 3706 // Construct a native method transfer processor for this class. 3707 TransferNativeFunctionRegistration(instanceKlassHandle _the_class) { 3708 assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); 3709 3710 the_class = _the_class; 3711 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count); 3712 } 3713 3714 // Attempt to transfer any of the old or deleted methods that are native 3715 void transfer_registrations(Method** old_methods, int methods_length) { 3716 for (int j = 0; j < methods_length; j++) { 3717 Method* old_method = old_methods[j]; 3718 3719 if (old_method->is_native() && old_method->has_native_function()) { 3720 Method* new_method = strip_and_search_for_new_native(old_method); 3721 if (new_method != NULL) { 3722 // Actually set the native function in the new method. 3723 // Redefine does not send events (except CFLH), certainly not this 3724 // behind the scenes re-registration. 3725 new_method->set_native_function(old_method->native_function(), 3726 !Method::native_bind_event_is_interesting); 3727 } 3728 } 3729 } 3730 } 3731 }; 3732 3733 // Don't lose the association between a native method and its JNI function. 3734 void VM_RedefineClasses::transfer_old_native_function_registrations(instanceKlassHandle the_class) { 3735 TransferNativeFunctionRegistration transfer(the_class); 3736 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length); 3737 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length); 3738 } 3739 3740 // Deoptimize all compiled code that depends on this class. 3741 // 3742 // If the can_redefine_classes capability is obtained in the onload 3743 // phase then the compiler has recorded all dependencies from startup. 3744 // In that case we need only deoptimize and throw away all compiled code 3745 // that depends on the class. 3746 // 3747 // If can_redefine_classes is obtained sometime after the onload 3748 // phase then the dependency information may be incomplete. In that case 3749 // the first call to RedefineClasses causes all compiled code to be 3750 // thrown away. As can_redefine_classes has been obtained then 3751 // all future compilations will record dependencies so second and 3752 // subsequent calls to RedefineClasses need only throw away code 3753 // that depends on the class. 3754 // 3755 void VM_RedefineClasses::flush_dependent_code(instanceKlassHandle k_h, TRAPS) { 3756 assert_locked_or_safepoint(Compile_lock); 3757 3758 // All dependencies have been recorded from startup or this is a second or 3759 // subsequent use of RedefineClasses 3760 if (JvmtiExport::all_dependencies_are_recorded()) { 3761 Universe::flush_evol_dependents_on(k_h); 3762 } else { 3763 CodeCache::mark_all_nmethods_for_deoptimization(); 3764 3765 ResourceMark rm(THREAD); 3766 DeoptimizationMarker dm; 3767 3768 // Deoptimize all activations depending on marked nmethods 3769 Deoptimization::deoptimize_dependents(); 3770 3771 // Make the dependent methods not entrant 3772 CodeCache::make_marked_nmethods_not_entrant(); 3773 3774 // From now on we know that the dependency information is complete 3775 JvmtiExport::set_all_dependencies_are_recorded(true); 3776 } 3777 } 3778 3779 void VM_RedefineClasses::compute_added_deleted_matching_methods() { 3780 Method* old_method; 3781 Method* new_method; 3782 3783 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 3784 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 3785 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length()); 3786 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); 3787 3788 _matching_methods_length = 0; 3789 _deleted_methods_length = 0; 3790 _added_methods_length = 0; 3791 3792 int nj = 0; 3793 int oj = 0; 3794 while (true) { 3795 if (oj >= _old_methods->length()) { 3796 if (nj >= _new_methods->length()) { 3797 break; // we've looked at everything, done 3798 } 3799 // New method at the end 3800 new_method = _new_methods->at(nj); 3801 _added_methods[_added_methods_length++] = new_method; 3802 ++nj; 3803 } else if (nj >= _new_methods->length()) { 3804 // Old method, at the end, is deleted 3805 old_method = _old_methods->at(oj); 3806 _deleted_methods[_deleted_methods_length++] = old_method; 3807 ++oj; 3808 } else { 3809 old_method = _old_methods->at(oj); 3810 new_method = _new_methods->at(nj); 3811 if (old_method->name() == new_method->name()) { 3812 if (old_method->signature() == new_method->signature()) { 3813 _matching_old_methods[_matching_methods_length ] = old_method; 3814 _matching_new_methods[_matching_methods_length++] = new_method; 3815 ++nj; 3816 ++oj; 3817 } else { 3818 // added overloaded have already been moved to the end, 3819 // so this is a deleted overloaded method 3820 _deleted_methods[_deleted_methods_length++] = old_method; 3821 ++oj; 3822 } 3823 } else { // names don't match 3824 if (old_method->name()->fast_compare(new_method->name()) > 0) { 3825 // new method 3826 _added_methods[_added_methods_length++] = new_method; 3827 ++nj; 3828 } else { 3829 // deleted method 3830 _deleted_methods[_deleted_methods_length++] = old_method; 3831 ++oj; 3832 } 3833 } 3834 } 3835 } 3836 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity"); 3837 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity"); 3838 } 3839 3840 3841 void VM_RedefineClasses::swap_annotations(instanceKlassHandle the_class, 3842 instanceKlassHandle scratch_class) { 3843 // Swap annotation fields values 3844 Annotations* old_annotations = the_class->annotations(); 3845 the_class->set_annotations(scratch_class->annotations()); 3846 scratch_class->set_annotations(old_annotations); 3847 } 3848 3849 3850 // Install the redefinition of a class: 3851 // - house keeping (flushing breakpoints and caches, deoptimizing 3852 // dependent compiled code) 3853 // - replacing parts in the_class with parts from scratch_class 3854 // - adding a weak reference to track the obsolete but interesting 3855 // parts of the_class 3856 // - adjusting constant pool caches and vtables in other classes 3857 // that refer to methods in the_class. These adjustments use the 3858 // ClassLoaderDataGraph::classes_do() facility which only allows 3859 // a helper method to be specified. The interesting parameters 3860 // that we would like to pass to the helper method are saved in 3861 // static global fields in the VM operation. 3862 void VM_RedefineClasses::redefine_single_class(jclass the_jclass, 3863 Klass* scratch_class_oop, TRAPS) { 3864 3865 HandleMark hm(THREAD); // make sure handles from this call are freed 3866 RC_TIMER_START(_timer_rsc_phase1); 3867 3868 instanceKlassHandle scratch_class(scratch_class_oop); 3869 3870 oop the_class_mirror = JNIHandles::resolve_non_null(the_jclass); 3871 Klass* the_class_oop = java_lang_Class::as_Klass(the_class_mirror); 3872 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop); 3873 3874 // Remove all breakpoints in methods of this class 3875 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints(); 3876 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class_oop); 3877 3878 // Deoptimize all compiled code that depends on this class 3879 flush_dependent_code(the_class, THREAD); 3880 3881 _old_methods = the_class->methods(); 3882 _new_methods = scratch_class->methods(); 3883 _the_class_oop = the_class_oop; 3884 compute_added_deleted_matching_methods(); 3885 update_jmethod_ids(); 3886 3887 // Attach new constant pool to the original klass. The original 3888 // klass still refers to the old constant pool (for now). 3889 scratch_class->constants()->set_pool_holder(the_class()); 3890 3891 #if 0 3892 // In theory, with constant pool merging in place we should be able 3893 // to save space by using the new, merged constant pool in place of 3894 // the old constant pool(s). By "pool(s)" I mean the constant pool in 3895 // the klass version we are replacing now and any constant pool(s) in 3896 // previous versions of klass. Nice theory, doesn't work in practice. 3897 // When this code is enabled, even simple programs throw NullPointer 3898 // exceptions. I'm guessing that this is caused by some constant pool 3899 // cache difference between the new, merged constant pool and the 3900 // constant pool that was just being used by the klass. I'm keeping 3901 // this code around to archive the idea, but the code has to remain 3902 // disabled for now. 3903 3904 // Attach each old method to the new constant pool. This can be 3905 // done here since we are past the bytecode verification and 3906 // constant pool optimization phases. 3907 for (int i = _old_methods->length() - 1; i >= 0; i--) { 3908 Method* method = _old_methods->at(i); 3909 method->set_constants(scratch_class->constants()); 3910 } 3911 3912 { 3913 // walk all previous versions of the klass 3914 InstanceKlass *ik = (InstanceKlass *)the_class(); 3915 PreviousVersionWalker pvw(ik); 3916 instanceKlassHandle ikh; 3917 do { 3918 ikh = pvw.next_previous_version(); 3919 if (!ikh.is_null()) { 3920 ik = ikh(); 3921 3922 // attach previous version of klass to the new constant pool 3923 ik->set_constants(scratch_class->constants()); 3924 3925 // Attach each method in the previous version of klass to the 3926 // new constant pool 3927 Array<Method*>* prev_methods = ik->methods(); 3928 for (int i = prev_methods->length() - 1; i >= 0; i--) { 3929 Method* method = prev_methods->at(i); 3930 method->set_constants(scratch_class->constants()); 3931 } 3932 } 3933 } while (!ikh.is_null()); 3934 } 3935 #endif 3936 3937 // Replace methods and constantpool 3938 the_class->set_methods(_new_methods); 3939 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods, 3940 // and to be able to undo operation easily. 3941 3942 Array<int>* old_ordering = the_class->method_ordering(); 3943 the_class->set_method_ordering(scratch_class->method_ordering()); 3944 scratch_class->set_method_ordering(old_ordering); 3945 3946 ConstantPool* old_constants = the_class->constants(); 3947 the_class->set_constants(scratch_class->constants()); 3948 scratch_class->set_constants(old_constants); // See the previous comment. 3949 #if 0 3950 // We are swapping the guts of "the new class" with the guts of "the 3951 // class". Since the old constant pool has just been attached to "the 3952 // new class", it seems logical to set the pool holder in the old 3953 // constant pool also. However, doing this will change the observable 3954 // class hierarchy for any old methods that are still executing. A 3955 // method can query the identity of its "holder" and this query uses 3956 // the method's constant pool link to find the holder. The change in 3957 // holding class from "the class" to "the new class" can confuse 3958 // things. 3959 // 3960 // Setting the old constant pool's holder will also cause 3961 // verification done during vtable initialization below to fail. 3962 // During vtable initialization, the vtable's class is verified to be 3963 // a subtype of the method's holder. The vtable's class is "the 3964 // class" and the method's holder is gotten from the constant pool 3965 // link in the method itself. For "the class"'s directly implemented 3966 // methods, the method holder is "the class" itself (as gotten from 3967 // the new constant pool). The check works fine in this case. The 3968 // check also works fine for methods inherited from super classes. 3969 // 3970 // Miranda methods are a little more complicated. A miranda method is 3971 // provided by an interface when the class implementing the interface 3972 // does not provide its own method. These interfaces are implemented 3973 // internally as an InstanceKlass. These special instanceKlasses 3974 // share the constant pool of the class that "implements" the 3975 // interface. By sharing the constant pool, the method holder of a 3976 // miranda method is the class that "implements" the interface. In a 3977 // non-redefine situation, the subtype check works fine. However, if 3978 // the old constant pool's pool holder is modified, then the check 3979 // fails because there is no class hierarchy relationship between the 3980 // vtable's class and "the new class". 3981 3982 old_constants->set_pool_holder(scratch_class()); 3983 #endif 3984 3985 // track number of methods that are EMCP for add_previous_version() call below 3986 int emcp_method_count = check_methods_and_mark_as_obsolete(); 3987 transfer_old_native_function_registrations(the_class); 3988 3989 // The class file bytes from before any retransformable agents mucked 3990 // with them was cached on the scratch class, move to the_class. 3991 // Note: we still want to do this if nothing needed caching since it 3992 // should get cleared in the_class too. 3993 if (the_class->get_cached_class_file() == 0) { 3994 // the_class doesn't have a cache yet so copy it 3995 the_class->set_cached_class_file(scratch_class->get_cached_class_file()); 3996 } 3997 else if (scratch_class->get_cached_class_file() != 3998 the_class->get_cached_class_file()) { 3999 // The same class can be present twice in the scratch classes list or there 4000 // are multiple concurrent RetransformClasses calls on different threads. 4001 // In such cases we have to deallocate scratch_class cached_class_file. 4002 os::free(scratch_class->get_cached_class_file()); 4003 } 4004 4005 // NULL out in scratch class to not delete twice. The class to be redefined 4006 // always owns these bytes. 4007 scratch_class->set_cached_class_file(NULL); 4008 4009 // Replace inner_classes 4010 Array<u2>* old_inner_classes = the_class->inner_classes(); 4011 the_class->set_inner_classes(scratch_class->inner_classes()); 4012 scratch_class->set_inner_classes(old_inner_classes); 4013 4014 // Initialize the vtable and interface table after 4015 // methods have been rewritten 4016 { 4017 ResourceMark rm(THREAD); 4018 // no exception should happen here since we explicitly 4019 // do not check loader constraints. 4020 // compare_and_normalize_class_versions has already checked: 4021 // - classloaders unchanged, signatures unchanged 4022 // - all instanceKlasses for redefined classes reused & contents updated 4023 the_class->vtable()->initialize_vtable(false, THREAD); 4024 the_class->itable()->initialize_itable(false, THREAD); 4025 assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())), "redefine exception"); 4026 } 4027 4028 // Leave arrays of jmethodIDs and itable index cache unchanged 4029 4030 // Copy the "source file name" attribute from new class version 4031 the_class->set_source_file_name_index( 4032 scratch_class->source_file_name_index()); 4033 4034 // Copy the "source debug extension" attribute from new class version 4035 the_class->set_source_debug_extension( 4036 scratch_class->source_debug_extension(), 4037 scratch_class->source_debug_extension() == NULL ? 0 : 4038 (int)strlen(scratch_class->source_debug_extension())); 4039 4040 // Use of javac -g could be different in the old and the new 4041 if (scratch_class->access_flags().has_localvariable_table() != 4042 the_class->access_flags().has_localvariable_table()) { 4043 4044 AccessFlags flags = the_class->access_flags(); 4045 if (scratch_class->access_flags().has_localvariable_table()) { 4046 flags.set_has_localvariable_table(); 4047 } else { 4048 flags.clear_has_localvariable_table(); 4049 } 4050 the_class->set_access_flags(flags); 4051 } 4052 4053 swap_annotations(the_class, scratch_class); 4054 4055 // Replace minor version number of class file 4056 u2 old_minor_version = the_class->minor_version(); 4057 the_class->set_minor_version(scratch_class->minor_version()); 4058 scratch_class->set_minor_version(old_minor_version); 4059 4060 // Replace major version number of class file 4061 u2 old_major_version = the_class->major_version(); 4062 the_class->set_major_version(scratch_class->major_version()); 4063 scratch_class->set_major_version(old_major_version); 4064 4065 // Replace CP indexes for class and name+type of enclosing method 4066 u2 old_class_idx = the_class->enclosing_method_class_index(); 4067 u2 old_method_idx = the_class->enclosing_method_method_index(); 4068 the_class->set_enclosing_method_indices( 4069 scratch_class->enclosing_method_class_index(), 4070 scratch_class->enclosing_method_method_index()); 4071 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx); 4072 4073 the_class->set_has_been_redefined(); 4074 4075 // keep track of previous versions of this class 4076 the_class->add_previous_version(scratch_class, emcp_method_count); 4077 4078 RC_TIMER_STOP(_timer_rsc_phase1); 4079 RC_TIMER_START(_timer_rsc_phase2); 4080 4081 // Adjust constantpool caches and vtables for all classes 4082 // that reference methods of the evolved class. 4083 AdjustCpoolCacheAndVtable adjust_cpool_cache_and_vtable(THREAD); 4084 ClassLoaderDataGraph::classes_do(&adjust_cpool_cache_and_vtable); 4085 4086 // JSR-292 support 4087 MemberNameTable* mnt = the_class->member_names(); 4088 if (mnt != NULL) { 4089 bool trace_name_printed = false; 4090 mnt->adjust_method_entries(the_class(), &trace_name_printed); 4091 } 4092 4093 if (the_class->oop_map_cache() != NULL) { 4094 // Flush references to any obsolete methods from the oop map cache 4095 // so that obsolete methods are not pinned. 4096 the_class->oop_map_cache()->flush_obsolete_entries(); 4097 } 4098 4099 // increment the classRedefinedCount field in the_class and in any 4100 // direct and indirect subclasses of the_class 4101 increment_class_counter((InstanceKlass *)the_class(), THREAD); 4102 4103 // RC_TRACE macro has an embedded ResourceMark 4104 RC_TRACE_WITH_THREAD(0x00000001, THREAD, 4105 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)", 4106 the_class->external_name(), 4107 java_lang_Class::classRedefinedCount(the_class_mirror), 4108 os::available_memory() >> 10)); 4109 4110 { 4111 ResourceMark rm(THREAD); 4112 Events::log_redefinition(THREAD, "redefined class name=%s, count=%d", 4113 the_class->external_name(), 4114 java_lang_Class::classRedefinedCount(the_class_mirror)); 4115 4116 } 4117 RC_TIMER_STOP(_timer_rsc_phase2); 4118 } // end redefine_single_class() 4119 4120 4121 // Increment the classRedefinedCount field in the specific InstanceKlass 4122 // and in all direct and indirect subclasses. 4123 void VM_RedefineClasses::increment_class_counter(InstanceKlass *ik, TRAPS) { 4124 oop class_mirror = ik->java_mirror(); 4125 Klass* class_oop = java_lang_Class::as_Klass(class_mirror); 4126 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1; 4127 java_lang_Class::set_classRedefinedCount(class_mirror, new_count); 4128 4129 if (class_oop != _the_class_oop) { 4130 // _the_class_oop count is printed at end of redefine_single_class() 4131 RC_TRACE_WITH_THREAD(0x00000008, THREAD, 4132 ("updated count in subclass=%s to %d", ik->external_name(), new_count)); 4133 } 4134 4135 for (Klass *subk = ik->subklass(); subk != NULL; 4136 subk = subk->next_sibling()) { 4137 if (subk->oop_is_instance()) { 4138 // Only update instanceKlasses 4139 InstanceKlass *subik = (InstanceKlass*)subk; 4140 // recursively do subclasses of the current subclass 4141 increment_class_counter(subik, THREAD); 4142 } 4143 } 4144 } 4145 4146 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) { 4147 bool no_old_methods = true; // be optimistic 4148 4149 // Both array and instance classes have vtables. 4150 // a vtable should never contain old or obsolete methods 4151 ResourceMark rm(_thread); 4152 if (k->vtable_length() > 0 && 4153 !k->vtable()->check_no_old_or_obsolete_entries()) { 4154 if (RC_TRACE_ENABLED(0x00004000)) { 4155 RC_TRACE_WITH_THREAD(0x00004000, _thread, 4156 ("klassVtable::check_no_old_or_obsolete_entries failure" 4157 " -- OLD or OBSOLETE method found -- class: %s", 4158 k->signature_name())); 4159 k->vtable()->dump_vtable(); 4160 } 4161 no_old_methods = false; 4162 } 4163 4164 if (k->oop_is_instance()) { 4165 HandleMark hm(_thread); 4166 InstanceKlass *ik = InstanceKlass::cast(k); 4167 4168 // an itable should never contain old or obsolete methods 4169 if (ik->itable_length() > 0 && 4170 !ik->itable()->check_no_old_or_obsolete_entries()) { 4171 if (RC_TRACE_ENABLED(0x00004000)) { 4172 RC_TRACE_WITH_THREAD(0x00004000, _thread, 4173 ("klassItable::check_no_old_or_obsolete_entries failure" 4174 " -- OLD or OBSOLETE method found -- class: %s", 4175 ik->signature_name())); 4176 ik->itable()->dump_itable(); 4177 } 4178 no_old_methods = false; 4179 } 4180 4181 // the constant pool cache should never contain non-deleted old or obsolete methods 4182 if (ik->constants() != NULL && 4183 ik->constants()->cache() != NULL && 4184 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) { 4185 if (RC_TRACE_ENABLED(0x00004000)) { 4186 RC_TRACE_WITH_THREAD(0x00004000, _thread, 4187 ("cp-cache::check_no_old_or_obsolete_entries failure" 4188 " -- OLD or OBSOLETE method found -- class: %s", 4189 ik->signature_name())); 4190 ik->constants()->cache()->dump_cache(); 4191 } 4192 no_old_methods = false; 4193 } 4194 } 4195 4196 // print and fail guarantee if old methods are found. 4197 if (!no_old_methods) { 4198 if (RC_TRACE_ENABLED(0x00004000)) { 4199 dump_methods(); 4200 } else { 4201 tty->print_cr("INFO: use the '-XX:TraceRedefineClasses=16384' option " 4202 "to see more info about the following guarantee() failure."); 4203 } 4204 guarantee(false, "OLD and/or OBSOLETE method(s) found"); 4205 } 4206 } 4207 4208 4209 void VM_RedefineClasses::dump_methods() { 4210 int j; 4211 RC_TRACE(0x00004000, ("_old_methods --")); 4212 for (j = 0; j < _old_methods->length(); ++j) { 4213 Method* m = _old_methods->at(j); 4214 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index())); 4215 m->access_flags().print_on(tty); 4216 tty->print(" -- "); 4217 m->print_name(tty); 4218 tty->cr(); 4219 } 4220 RC_TRACE(0x00004000, ("_new_methods --")); 4221 for (j = 0; j < _new_methods->length(); ++j) { 4222 Method* m = _new_methods->at(j); 4223 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index())); 4224 m->access_flags().print_on(tty); 4225 tty->print(" -- "); 4226 m->print_name(tty); 4227 tty->cr(); 4228 } 4229 RC_TRACE(0x00004000, ("_matching_(old/new)_methods --")); 4230 for (j = 0; j < _matching_methods_length; ++j) { 4231 Method* m = _matching_old_methods[j]; 4232 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index())); 4233 m->access_flags().print_on(tty); 4234 tty->print(" -- "); 4235 m->print_name(tty); 4236 tty->cr(); 4237 m = _matching_new_methods[j]; 4238 RC_TRACE_NO_CR(0x00004000, (" (%5d) ", m->vtable_index())); 4239 m->access_flags().print_on(tty); 4240 tty->cr(); 4241 } 4242 RC_TRACE(0x00004000, ("_deleted_methods --")); 4243 for (j = 0; j < _deleted_methods_length; ++j) { 4244 Method* m = _deleted_methods[j]; 4245 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index())); 4246 m->access_flags().print_on(tty); 4247 tty->print(" -- "); 4248 m->print_name(tty); 4249 tty->cr(); 4250 } 4251 RC_TRACE(0x00004000, ("_added_methods --")); 4252 for (j = 0; j < _added_methods_length; ++j) { 4253 Method* m = _added_methods[j]; 4254 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index())); 4255 m->access_flags().print_on(tty); 4256 tty->print(" -- "); 4257 m->print_name(tty); 4258 tty->cr(); 4259 } 4260 } 4261 4262 void VM_RedefineClasses::print_on_error(outputStream* st) const { 4263 VM_Operation::print_on_error(st); 4264 if (_the_class_oop != NULL) { 4265 ResourceMark rm; 4266 st->print_cr(", redefining class %s", _the_class_oop->external_name()); 4267 } 4268 }