1 /*
2 * Copyright (c) 2003, 2025, 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 "cds/aotMetaspace.hpp"
26 #include "cds/cdsConfig.hpp"
27 #include "classfile/classFileStream.hpp"
28 #include "classfile/classLoaderDataGraph.hpp"
29 #include "classfile/classLoadInfo.hpp"
30 #include "classfile/javaClasses.inline.hpp"
31 #include "classfile/klassFactory.hpp"
32 #include "classfile/metadataOnStackMark.hpp"
33 #include "classfile/stackMapTable.hpp"
34 #include "classfile/symbolTable.hpp"
35 #include "classfile/verifier.hpp"
36 #include "classfile/vmClasses.hpp"
37 #include "classfile/vmSymbols.hpp"
38 #include "code/codeCache.hpp"
39 #include "compiler/compileBroker.hpp"
40 #include "interpreter/oopMapCache.hpp"
41 #include "interpreter/rewriter.hpp"
42 #include "jfr/jfrEvents.hpp"
43 #include "logging/logStream.hpp"
44 #include "memory/metadataFactory.hpp"
45 #include "memory/resourceArea.hpp"
46 #include "memory/universe.hpp"
47 #include "oops/annotations.hpp"
48 #include "oops/bsmAttribute.inline.hpp"
49 #include "oops/constantPool.inline.hpp"
50 #include "oops/fieldStreams.inline.hpp"
51 #include "oops/klass.inline.hpp"
52 #include "oops/klassVtable.hpp"
53 #include "oops/method.hpp"
54 #include "oops/oop.inline.hpp"
55 #include "oops/recordComponent.hpp"
56 #include "oops/trainingData.hpp"
57 #include "prims/jvmtiImpl.hpp"
58 #include "prims/jvmtiRedefineClasses.hpp"
59 #include "prims/jvmtiThreadState.inline.hpp"
60 #include "prims/methodComparator.hpp"
61 #include "prims/resolvedMethodTable.hpp"
62 #include "runtime/atomicAccess.hpp"
63 #include "runtime/deoptimization.hpp"
64 #include "runtime/handles.inline.hpp"
65 #include "runtime/jniHandles.inline.hpp"
66 #include "runtime/relocator.hpp"
67 #include "runtime/safepointVerifiers.hpp"
68 #include "utilities/bitMap.inline.hpp"
69 #include "utilities/checkedCast.hpp"
70 #include "utilities/events.hpp"
71 #include "utilities/macros.hpp"
72 #if INCLUDE_JFR
73 #include "jfr/jfr.hpp"
74 #endif
75
76 Array<Method*>* VM_RedefineClasses::_old_methods = nullptr;
77 Array<Method*>* VM_RedefineClasses::_new_methods = nullptr;
78 Method** VM_RedefineClasses::_matching_old_methods = nullptr;
79 Method** VM_RedefineClasses::_matching_new_methods = nullptr;
80 Method** VM_RedefineClasses::_deleted_methods = nullptr;
81 Method** VM_RedefineClasses::_added_methods = nullptr;
82 int VM_RedefineClasses::_matching_methods_length = 0;
83 int VM_RedefineClasses::_deleted_methods_length = 0;
84 int VM_RedefineClasses::_added_methods_length = 0;
85
86 // This flag is global as the constructor does not reset it:
87 bool VM_RedefineClasses::_has_redefined_Object = false;
88 u8 VM_RedefineClasses::_id_counter = 0;
89
90 VM_RedefineClasses::VM_RedefineClasses(jint class_count,
91 const jvmtiClassDefinition *class_defs,
92 JvmtiClassLoadKind class_load_kind) {
93 _class_count = class_count;
94 _class_defs = class_defs;
95 _class_load_kind = class_load_kind;
96 _any_class_has_resolved_methods = false;
97 _res = JVMTI_ERROR_NONE;
98 _the_class = nullptr;
99 _id = next_id();
100 }
101
102 static inline InstanceKlass* get_ik(jclass def) {
103 oop mirror = JNIHandles::resolve_non_null(def);
104 return java_lang_Class::as_InstanceKlass(mirror);
105 }
106
107 // If any of the classes are being redefined, wait
108 // Parallel constant pool merging leads to indeterminate constant pools.
109 void VM_RedefineClasses::lock_classes() {
110 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
111 GrowableArray<Klass*>* redef_classes = state->get_classes_being_redefined();
112
113 MonitorLocker ml(RedefineClasses_lock);
114
115 if (redef_classes == nullptr) {
116 redef_classes = new (mtClass) GrowableArray<Klass*>(1, mtClass);
117 state->set_classes_being_redefined(redef_classes);
118 }
119
120 bool has_redefined;
121 do {
122 has_redefined = false;
123 // Go through classes each time until none are being redefined. Skip
124 // the ones that are being redefined by this thread currently. Class file
125 // load hook event may trigger new class redefine when we are redefining
126 // a class (after lock_classes()).
127 for (int i = 0; i < _class_count; i++) {
128 InstanceKlass* ik = get_ik(_class_defs[i].klass);
129 // Check if we are currently redefining the class in this thread already.
130 if (redef_classes->contains(ik)) {
131 assert(ik->is_being_redefined(), "sanity");
132 } else {
133 if (ik->is_being_redefined()) {
134 ml.wait();
135 has_redefined = true;
136 break; // for loop
137 }
138 }
139 }
140 } while (has_redefined);
141
142 for (int i = 0; i < _class_count; i++) {
143 InstanceKlass* ik = get_ik(_class_defs[i].klass);
144 redef_classes->push(ik); // Add to the _classes_being_redefined list
145 ik->set_is_being_redefined(true);
146 }
147 ml.notify_all();
148 }
149
150 void VM_RedefineClasses::unlock_classes() {
151 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
152 GrowableArray<Klass*>* redef_classes = state->get_classes_being_redefined();
153 assert(redef_classes != nullptr, "_classes_being_redefined is not allocated");
154
155 MonitorLocker ml(RedefineClasses_lock);
156
157 for (int i = _class_count - 1; i >= 0; i--) {
158 InstanceKlass* def_ik = get_ik(_class_defs[i].klass);
159 if (redef_classes->length() > 0) {
160 // Remove the class from _classes_being_redefined list
161 Klass* k = redef_classes->pop();
162 assert(def_ik == k, "unlocking wrong class");
163 }
164 assert(def_ik->is_being_redefined(),
165 "should be being redefined to get here");
166
167 // Unlock after we finish all redefines for this class within
168 // the thread. Same class can be pushed to the list multiple
169 // times (not more than once by each recursive redefinition).
170 if (!redef_classes->contains(def_ik)) {
171 def_ik->set_is_being_redefined(false);
172 }
173 }
174 ml.notify_all();
175 }
176
177 bool VM_RedefineClasses::doit_prologue() {
178 if (_class_count == 0) {
179 _res = JVMTI_ERROR_NONE;
180 return false;
181 }
182 if (_class_defs == nullptr) {
183 _res = JVMTI_ERROR_NULL_POINTER;
184 return false;
185 }
186
187 for (int i = 0; i < _class_count; i++) {
188 if (_class_defs[i].klass == nullptr) {
189 _res = JVMTI_ERROR_INVALID_CLASS;
190 return false;
191 }
192 if (_class_defs[i].class_byte_count == 0) {
193 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT;
194 return false;
195 }
196 if (_class_defs[i].class_bytes == nullptr) {
197 _res = JVMTI_ERROR_NULL_POINTER;
198 return false;
199 }
200
201 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass);
202 // classes for primitives, arrays, and hidden classes
203 // cannot be redefined.
204 if (!is_modifiable_class(mirror)) {
205 _res = JVMTI_ERROR_UNMODIFIABLE_CLASS;
206 return false;
207 }
208 }
209
210 // Start timer after all the sanity checks; not quite accurate, but
211 // better than adding a bunch of stop() calls.
212 if (log_is_enabled(Info, redefine, class, timer)) {
213 _timer_vm_op_prologue.start();
214 }
215
216 lock_classes();
217 // We first load new class versions in the prologue, because somewhere down the
218 // call chain it is required that the current thread is a Java thread.
219 _res = load_new_class_versions();
220 if (_res != JVMTI_ERROR_NONE) {
221 // free any successfully created classes, since none are redefined
222 for (int i = 0; i < _class_count; i++) {
223 if (_scratch_classes[i] != nullptr) {
224 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data();
225 // Free the memory for this class at class unloading time. Not before
226 // because CMS might think this is still live.
227 InstanceKlass* ik = get_ik(_class_defs[i].klass);
228 if (ik->get_cached_class_file() == _scratch_classes[i]->get_cached_class_file()) {
229 // Don't double-free cached_class_file copied from the original class if error.
230 _scratch_classes[i]->set_cached_class_file(nullptr);
231 }
232 cld->add_to_deallocate_list(InstanceKlass::cast(_scratch_classes[i]));
233 }
234 }
235 // Free os::malloc allocated memory in load_new_class_version.
236 os::free(_scratch_classes);
237 _timer_vm_op_prologue.stop();
238 unlock_classes();
239 return false;
240 }
241
242 _timer_vm_op_prologue.stop();
243 return true;
244 }
245
246 void VM_RedefineClasses::doit() {
247 Thread* current = Thread::current();
248
249 if (log_is_enabled(Info, redefine, class, timer)) {
250 _timer_vm_op_doit.start();
251 }
252
253 #if INCLUDE_CDS
254 if (CDSConfig::is_using_archive()) {
255 // Sharing is enabled so we remap the shared readonly space to
256 // shared readwrite, private just in case we need to redefine
257 // a shared class. We do the remap during the doit() phase of
258 // the safepoint to be safer.
259 if (!AOTMetaspace::remap_shared_readonly_as_readwrite()) {
260 log_info(redefine, class, load)("failed to remap shared readonly space to readwrite, private");
261 _res = JVMTI_ERROR_INTERNAL;
262 _timer_vm_op_doit.stop();
263 return;
264 }
265 }
266 #endif
267
268 // Mark methods seen on stack and everywhere else so old methods are not
269 // cleaned up if they're on the stack.
270 MetadataOnStackMark md_on_stack(/*walk_all_metadata*/true, /*redefinition_walk*/true);
271 HandleMark hm(current); // make sure any handles created are deleted
272 // before the stack walk again.
273
274 for (int i = 0; i < _class_count; i++) {
275 redefine_single_class(current, _class_defs[i].klass, _scratch_classes[i]);
276 }
277
278 #if INCLUDE_CDS
279 TrainingData::cleanup_after_redefinition();
280 #endif
281
282 // Flush all compiled code that depends on the classes redefined.
283 flush_dependent_code();
284
285 // Adjust constantpool caches and vtables for all classes
286 // that reference methods of the evolved classes.
287 // Have to do this after all classes are redefined and all methods that
288 // are redefined are marked as old.
289 AdjustAndCleanMetadata adjust_and_clean_metadata(current);
290 ClassLoaderDataGraph::classes_do(&adjust_and_clean_metadata);
291
292 // JSR-292 support
293 if (_any_class_has_resolved_methods) {
294 bool trace_name_printed = false;
295 ResolvedMethodTable::adjust_method_entries(&trace_name_printed);
296 }
297
298 // Increment flag indicating that some invariants are no longer true.
299 // See jvmtiExport.hpp for detailed explanation.
300 JvmtiExport::increment_redefinition_count();
301
302 // check_class() is optionally called for product bits, but is
303 // always called for non-product bits.
304 #ifdef PRODUCT
305 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
306 #endif
307 log_trace(redefine, class, obsolete, metadata)("calling check_class");
308 CheckClass check_class(current);
309 ClassLoaderDataGraph::classes_do(&check_class);
310 #ifdef PRODUCT
311 }
312 #endif
313
314 // Clean up any metadata now unreferenced while MetadataOnStackMark is set.
315 ClassLoaderDataGraph::clean_deallocate_lists(false);
316
317 _timer_vm_op_doit.stop();
318 }
319
320 void VM_RedefineClasses::doit_epilogue() {
321 unlock_classes();
322
323 // Free os::malloc allocated memory.
324 os::free(_scratch_classes);
325
326 // Reset the_class to null for error printing.
327 _the_class = nullptr;
328
329 if (log_is_enabled(Info, redefine, class, timer)) {
330 // Used to have separate timers for "doit" and "all", but the timer
331 // overhead skewed the measurements.
332 julong doit_time = _timer_vm_op_doit.milliseconds();
333 julong all_time = _timer_vm_op_prologue.milliseconds() + doit_time;
334
335 log_info(redefine, class, timer)
336 ("vm_op: all=" JULONG_FORMAT " prologue=" JULONG_FORMAT " doit=" JULONG_FORMAT,
337 all_time, (julong)_timer_vm_op_prologue.milliseconds(), doit_time);
338 log_info(redefine, class, timer)
339 ("redefine_single_class: phase1=" JULONG_FORMAT " phase2=" JULONG_FORMAT,
340 (julong)_timer_rsc_phase1.milliseconds(), (julong)_timer_rsc_phase2.milliseconds());
341 }
342 }
343
344 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) {
345 // classes for primitives cannot be redefined
346 if (java_lang_Class::is_primitive(klass_mirror)) {
347 return false;
348 }
349 Klass* k = java_lang_Class::as_Klass(klass_mirror);
350 // classes for arrays cannot be redefined
351 if (k == nullptr || !k->is_instance_klass()) {
352 return false;
353 }
354
355 // Cannot redefine or retransform a hidden class.
356 if (InstanceKlass::cast(k)->is_hidden()) {
357 return false;
358 }
359 if (InstanceKlass::cast(k) == vmClasses::Continuation_klass()) {
360 // Don't redefine Continuation class. See 8302779.
361 return false;
362 }
363 return true;
364 }
365
366 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p
367 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For
368 // direct CP entries, there is just the current entry to append. For
369 // indirect and double-indirect CP entries, there are zero or more
370 // referenced CP entries along with the current entry to append.
371 // Indirect and double-indirect CP entries are handled by recursive
372 // calls to append_entry() as needed. The referenced CP entries are
373 // always appended to *merge_cp_p before the referee CP entry. These
374 // referenced CP entries may already exist in *merge_cp_p in which case
375 // there is nothing extra to append and only the current entry is
376 // appended.
377 void VM_RedefineClasses::append_entry(const constantPoolHandle& scratch_cp,
378 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) {
379
380 // append is different depending on entry tag type
381 switch (scratch_cp->tag_at(scratch_i).value()) {
382
383 // The old verifier is implemented outside the VM. It loads classes,
384 // but does not resolve constant pool entries directly so we never
385 // see Class entries here with the old verifier. Similarly the old
386 // verifier does not like Class entries in the input constant pool.
387 // The split-verifier is implemented in the VM so it can optionally
388 // and directly resolve constant pool entries to load classes. The
389 // split-verifier can accept either Class entries or UnresolvedClass
390 // entries in the input constant pool. We revert the appended copy
391 // back to UnresolvedClass so that either verifier will be happy
392 // with the constant pool entry.
393 //
394 // this is an indirect CP entry so it needs special handling
395 case JVM_CONSTANT_Class:
396 case JVM_CONSTANT_UnresolvedClass:
397 {
398 int name_i = scratch_cp->klass_name_index_at(scratch_i);
399 int new_name_i = find_or_append_indirect_entry(scratch_cp, name_i, merge_cp_p,
400 merge_cp_length_p);
401
402 if (new_name_i != name_i) {
403 log_trace(redefine, class, constantpool)
404 ("Class entry@%d name_index change: %d to %d",
405 *merge_cp_length_p, name_i, new_name_i);
406 }
407
408 (*merge_cp_p)->temp_unresolved_klass_at_put(*merge_cp_length_p, new_name_i);
409 if (scratch_i != *merge_cp_length_p) {
410 // The new entry in *merge_cp_p is at a different index than
411 // the new entry in scratch_cp so we need to map the index values.
412 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
413 }
414 (*merge_cp_length_p)++;
415 } break;
416
417 // these are direct CP entries so they can be directly appended,
418 // but double and long take two constant pool entries
419 case JVM_CONSTANT_Double: // fall through
420 case JVM_CONSTANT_Long:
421 {
422 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p);
423
424 if (scratch_i != *merge_cp_length_p) {
425 // The new entry in *merge_cp_p is at a different index than
426 // the new entry in scratch_cp so we need to map the index values.
427 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
428 }
429 (*merge_cp_length_p) += 2;
430 } break;
431
432 // these are direct CP entries so they can be directly appended
433 case JVM_CONSTANT_Float: // fall through
434 case JVM_CONSTANT_Integer: // fall through
435 case JVM_CONSTANT_Utf8: // fall through
436
437 // This was an indirect CP entry, but it has been changed into
438 // Symbol*s so this entry can be directly appended.
439 case JVM_CONSTANT_String: // fall through
440 {
441 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p);
442
443 if (scratch_i != *merge_cp_length_p) {
444 // The new entry in *merge_cp_p is at a different index than
445 // the new entry in scratch_cp so we need to map the index values.
446 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
447 }
448 (*merge_cp_length_p)++;
449 } break;
450
451 // this is an indirect CP entry so it needs special handling
452 case JVM_CONSTANT_NameAndType:
453 {
454 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i);
455 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p,
456 merge_cp_length_p);
457
458 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i);
459 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i,
460 merge_cp_p, merge_cp_length_p);
461
462 // If the referenced entries already exist in *merge_cp_p, then
463 // both new_name_ref_i and new_signature_ref_i will both be 0.
464 // In that case, all we are appending is the current entry.
465 if (new_name_ref_i != name_ref_i) {
466 log_trace(redefine, class, constantpool)
467 ("NameAndType entry@%d name_ref_index change: %d to %d",
468 *merge_cp_length_p, name_ref_i, new_name_ref_i);
469 }
470 if (new_signature_ref_i != signature_ref_i) {
471 log_trace(redefine, class, constantpool)
472 ("NameAndType entry@%d signature_ref_index change: %d to %d",
473 *merge_cp_length_p, signature_ref_i, new_signature_ref_i);
474 }
475
476 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p,
477 new_name_ref_i, new_signature_ref_i);
478 if (scratch_i != *merge_cp_length_p) {
479 // The new entry in *merge_cp_p is at a different index than
480 // the new entry in scratch_cp so we need to map the index values.
481 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
482 }
483 (*merge_cp_length_p)++;
484 } break;
485
486 // this is a double-indirect CP entry so it needs special handling
487 case JVM_CONSTANT_Fieldref: // fall through
488 case JVM_CONSTANT_InterfaceMethodref: // fall through
489 case JVM_CONSTANT_Methodref:
490 {
491 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i);
492 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i,
493 merge_cp_p, merge_cp_length_p);
494
495 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i);
496 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i,
497 merge_cp_p, merge_cp_length_p);
498
499 const char *entry_name = nullptr;
500 switch (scratch_cp->tag_at(scratch_i).value()) {
501 case JVM_CONSTANT_Fieldref:
502 entry_name = "Fieldref";
503 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i,
504 new_name_and_type_ref_i);
505 break;
506 case JVM_CONSTANT_InterfaceMethodref:
507 entry_name = "IFMethodref";
508 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p,
509 new_klass_ref_i, new_name_and_type_ref_i);
510 break;
511 case JVM_CONSTANT_Methodref:
512 entry_name = "Methodref";
513 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i,
514 new_name_and_type_ref_i);
515 break;
516 default:
517 guarantee(false, "bad switch");
518 break;
519 }
520
521 if (klass_ref_i != new_klass_ref_i) {
522 log_trace(redefine, class, constantpool)
523 ("%s entry@%d class_index changed: %d to %d", entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i);
524 }
525 if (name_and_type_ref_i != new_name_and_type_ref_i) {
526 log_trace(redefine, class, constantpool)
527 ("%s entry@%d name_and_type_index changed: %d to %d",
528 entry_name, *merge_cp_length_p, name_and_type_ref_i, new_name_and_type_ref_i);
529 }
530
531 if (scratch_i != *merge_cp_length_p) {
532 // The new entry in *merge_cp_p is at a different index than
533 // the new entry in scratch_cp so we need to map the index values.
534 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
535 }
536 (*merge_cp_length_p)++;
537 } break;
538
539 // this is an indirect CP entry so it needs special handling
540 case JVM_CONSTANT_MethodType:
541 {
542 int ref_i = scratch_cp->method_type_index_at(scratch_i);
543 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
544 merge_cp_length_p);
545 if (new_ref_i != ref_i) {
546 log_trace(redefine, class, constantpool)
547 ("MethodType entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i);
548 }
549 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i);
550 if (scratch_i != *merge_cp_length_p) {
551 // The new entry in *merge_cp_p is at a different index than
552 // the new entry in scratch_cp so we need to map the index values.
553 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
554 }
555 (*merge_cp_length_p)++;
556 } break;
557
558 // this is an indirect CP entry so it needs special handling
559 case JVM_CONSTANT_MethodHandle:
560 {
561 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i);
562 int ref_i = scratch_cp->method_handle_index_at(scratch_i);
563 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
564 merge_cp_length_p);
565 if (new_ref_i != ref_i) {
566 log_trace(redefine, class, constantpool)
567 ("MethodHandle entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i);
568 }
569 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i);
570 if (scratch_i != *merge_cp_length_p) {
571 // The new entry in *merge_cp_p is at a different index than
572 // the new entry in scratch_cp so we need to map the index values.
573 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
574 }
575 (*merge_cp_length_p)++;
576 } break;
577
578 // this is an indirect CP entry so it needs special handling
579 case JVM_CONSTANT_Dynamic: // fall through
580 case JVM_CONSTANT_InvokeDynamic:
581 {
582 // Index of the bootstrap specifier in the BSM array
583 int old_bs_i = scratch_cp->bootstrap_methods_attribute_index(scratch_i);
584 int new_bs_i = find_or_append_bsm_entry(scratch_cp, old_bs_i, merge_cp_p,
585 merge_cp_length_p);
586 // The bootstrap method NameAndType_info index
587 int old_ref_i = scratch_cp->bootstrap_name_and_type_ref_index_at(scratch_i);
588 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
589 merge_cp_length_p);
590 if (new_bs_i != old_bs_i) {
591 log_trace(redefine, class, constantpool)
592 ("Dynamic entry@%d bootstrap_method_attr_index change: %d to %d",
593 *merge_cp_length_p, old_bs_i, new_bs_i);
594 }
595 if (new_ref_i != old_ref_i) {
596 log_trace(redefine, class, constantpool)
597 ("Dynamic entry@%d name_and_type_index change: %d to %d", *merge_cp_length_p, old_ref_i, new_ref_i);
598 }
599
600 if (scratch_cp->tag_at(scratch_i).is_dynamic_constant()) {
601 (*merge_cp_p)->dynamic_constant_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
602 } else {
603 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
604 }
605 if (scratch_i != *merge_cp_length_p) {
606 // The new entry in *merge_cp_p is at a different index than
607 // the new entry in scratch_cp so we need to map the index values.
608 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
609 }
610 (*merge_cp_length_p)++;
611 } break;
612
613 // At this stage, Class or UnresolvedClass could be in scratch_cp, but not
614 // ClassIndex
615 case JVM_CONSTANT_ClassIndex: // fall through
616
617 // Invalid is used as the tag for the second constant pool entry
618 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
619 // not be seen by itself.
620 case JVM_CONSTANT_Invalid: // fall through
621
622 // At this stage, String could be here, but not StringIndex
623 case JVM_CONSTANT_StringIndex: // fall through
624
625 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be
626 // here
627 case JVM_CONSTANT_UnresolvedClassInError: // fall through
628
629 default:
630 {
631 // leave a breadcrumb
632 jbyte bad_value = scratch_cp->tag_at(scratch_i).value();
633 ShouldNotReachHere();
634 } break;
635 } // end switch tag value
636 } // end append_entry()
637
638
639 u2 VM_RedefineClasses::find_or_append_indirect_entry(const constantPoolHandle& scratch_cp,
640 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) {
641
642 int new_ref_i = ref_i;
643 bool match = (ref_i < *merge_cp_length_p) &&
644 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i);
645
646 if (!match) {
647 // forward reference in *merge_cp_p or not a direct match
648 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p);
649 if (found_i != 0) {
650 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree");
651 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry.
652 new_ref_i = found_i;
653 map_index(scratch_cp, ref_i, found_i);
654 } else {
655 // no match found so we have to append this entry to *merge_cp_p
656 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p);
657 // The above call to append_entry() can only append one entry
658 // so the post call query of *merge_cp_length_p is only for
659 // the sake of consistency.
660 new_ref_i = *merge_cp_length_p - 1;
661 }
662 }
663
664 // constant pool indices are u2, unless the merged constant pool overflows which
665 // we don't check for.
666 return checked_cast<u2>(new_ref_i);
667 } // end find_or_append_indirect_entry()
668
669
670 // Append a bootstrap specifier into the merge_cp BSM entries that is semantically equal
671 // to the scratch_cp BSM entries' bootstrap specifier passed by the old_bs_i index.
672 // Recursively append new merge_cp entries referenced by the new bootstrap specifier.
673 int VM_RedefineClasses::append_bsm_entry(const constantPoolHandle& scratch_cp, const int old_bs_i,
674 constantPoolHandle *merge_cp_p, int *merge_cp_length_p) {
675
676 BSMAttributeEntry* old_bsme = scratch_cp->bsm_attribute_entry(old_bs_i);
677 u2 old_ref_i = old_bsme->bootstrap_method_index();
678 u2 new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
679 merge_cp_length_p);
680 if (new_ref_i != old_ref_i) {
681 log_trace(redefine, class, constantpool)
682 ("BSM attribute entry@%d bootstrap method ref_index change: %d to %d", _bsmae_iter.current_offset() - 1, old_ref_i, new_ref_i);
683 }
684
685 const int new_bs_i = _bsmae_iter.current_offset();
686 BSMAttributeEntry* new_bsme =
687 _bsmae_iter.reserve_new_entry(new_ref_i, old_bsme->argument_count());
688 assert(new_bsme != nullptr, "must be");
689 for (int i = 0; i < new_bsme->argument_count(); i++) {
690 u2 old_arg_ref_i = old_bsme->argument(i);
691 u2 new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p,
692 merge_cp_length_p);
693 new_bsme->set_argument(i, new_arg_ref_i);
694
695 if (new_arg_ref_i != old_arg_ref_i) {
696 log_trace(redefine, class, constantpool)
697 ("BSM attribute entry@%d bootstrap method argument ref_index change: %d to %d",
698 _bsmae_iter.current_offset() - 1, old_arg_ref_i, new_arg_ref_i);
699 }
700 }
701 // This is only for the logging
702 map_bsm_index(old_bs_i, new_bs_i);
703 return new_bs_i;
704 } // end append_bsm_entry()
705
706
707 int VM_RedefineClasses::find_or_append_bsm_entry(const constantPoolHandle& scratch_cp,
708 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) {
709
710 const int max_offset_in_merge = _bsmae_iter.current_offset();
711 int new_bs_i = old_bs_i; // bootstrap specifier index
712 // Has the old_bs_i index been used already? Check if it's the same so we know
713 // whether or not a remapping is required.
714 bool match = (old_bs_i < max_offset_in_merge) &&
715 scratch_cp->compare_bootstrap_entry_to(old_bs_i, *merge_cp_p, old_bs_i);
716
717 if (!match) {
718 // forward reference in *merge_cp_p or not a direct match
719 int found_i = scratch_cp->find_matching_bsm_entry(old_bs_i, *merge_cp_p,
720 max_offset_in_merge);
721 if (found_i != -1) {
722 guarantee(found_i != old_bs_i, "compare_bootstrap_entry_to() and find_matching_bsm_entry() disagree");
723 // found a matching BSM entry somewhere else in *merge_cp_p so just need a mapping
724 new_bs_i = found_i;
725 map_bsm_index(old_bs_i, found_i);
726 } else {
727 // no match found so we have to append this bootstrap specifier to *merge_cp_p
728 new_bs_i = append_bsm_entry(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p);
729 }
730 }
731 return new_bs_i;
732 } // end find_or_append_bsm_entry()
733
734
735 void VM_RedefineClasses::finalize_bsm_entries_merge(const constantPoolHandle& merge_cp, TRAPS) {
736 if (merge_cp->bsm_entries().number_of_entries() == 0) {
737 return;
738 }
739 // Finished extending the BSMAEs
740 merge_cp->end_extension(_bsmae_iter, CHECK);
741
742 if (log_is_enabled(Trace, redefine, class, constantpool)) {
743 // don't want to loop unless we are tracing
744 int count = 0;
745 for (int i = 1; i < _bsm_index_map_p->length(); i++) {
746 int value = _bsm_index_map_p->at(i);
747 if (value != -1) {
748 log_trace(redefine, class, constantpool)("bsm_index_map[%d]: old=%d new=%d", count, i, value);
749 count++;
750 }
751 }
752 }
753 // Clean-up
754 _bsm_index_map_p = nullptr;
755 _bsm_index_map_count = 0;
756 _bsmae_iter = BSMAttributeEntries::InsertionIterator();
757 } // end finalize_bsmentries_merge()
758
759 // Symbol* comparator for qsort
760 // The caller must have an active ResourceMark.
761 static int symcmp(const void* a, const void* b) {
762 char* astr = (*(Symbol**)a)->as_C_string();
763 char* bstr = (*(Symbol**)b)->as_C_string();
764 return strcmp(astr, bstr);
765 }
766
767 // The caller must have an active ResourceMark.
768 static jvmtiError check_attribute_arrays(const char* attr_name,
769 InstanceKlass* the_class, InstanceKlass* scratch_class,
770 Array<u2>* the_array, Array<u2>* scr_array) {
771 bool the_array_exists = the_array != Universe::the_empty_short_array();
772 bool scr_array_exists = scr_array != Universe::the_empty_short_array();
773
774 int array_len = the_array->length();
775 if (the_array_exists && scr_array_exists) {
776 if (array_len != scr_array->length()) {
777 log_trace(redefine, class)
778 ("redefined class %s attribute change error: %s len=%d changed to len=%d",
779 the_class->external_name(), attr_name, array_len, scr_array->length());
780 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
781 }
782
783 // The order of entries in the attribute array is not specified so we
784 // have to explicitly check for the same contents. We do this by copying
785 // the referenced symbols into their own arrays, sorting them and then
786 // comparing each element pair.
787
788 Symbol** the_syms = NEW_RESOURCE_ARRAY_RETURN_NULL(Symbol*, array_len);
789 Symbol** scr_syms = NEW_RESOURCE_ARRAY_RETURN_NULL(Symbol*, array_len);
790
791 if (the_syms == nullptr || scr_syms == nullptr) {
792 return JVMTI_ERROR_OUT_OF_MEMORY;
793 }
794
795 for (int i = 0; i < array_len; i++) {
796 int the_cp_index = the_array->at(i);
797 int scr_cp_index = scr_array->at(i);
798 the_syms[i] = the_class->constants()->klass_name_at(the_cp_index);
799 scr_syms[i] = scratch_class->constants()->klass_name_at(scr_cp_index);
800 }
801
802 qsort(the_syms, array_len, sizeof(Symbol*), symcmp);
803 qsort(scr_syms, array_len, sizeof(Symbol*), symcmp);
804
805 for (int i = 0; i < array_len; i++) {
806 if (the_syms[i] != scr_syms[i]) {
807 log_info(redefine, class)
808 ("redefined class %s attribute change error: %s[%d]: %s changed to %s",
809 the_class->external_name(), attr_name, i,
810 the_syms[i]->as_C_string(), scr_syms[i]->as_C_string());
811 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
812 }
813 }
814 } else if (the_array_exists ^ scr_array_exists) {
815 const char* action_str = (the_array_exists) ? "removed" : "added";
816 log_info(redefine, class)
817 ("redefined class %s attribute change error: %s attribute %s",
818 the_class->external_name(), attr_name, action_str);
819 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
820 }
821 return JVMTI_ERROR_NONE;
822 }
823
824 static jvmtiError check_nest_attributes(InstanceKlass* the_class,
825 InstanceKlass* scratch_class) {
826 // Check whether the class NestHost attribute has been changed.
827 Thread* thread = Thread::current();
828 ResourceMark rm(thread);
829 u2 the_nest_host_idx = the_class->nest_host_index();
830 u2 scr_nest_host_idx = scratch_class->nest_host_index();
831
832 if (the_nest_host_idx != 0 && scr_nest_host_idx != 0) {
833 Symbol* the_sym = the_class->constants()->klass_name_at(the_nest_host_idx);
834 Symbol* scr_sym = scratch_class->constants()->klass_name_at(scr_nest_host_idx);
835 if (the_sym != scr_sym) {
836 log_info(redefine, class, nestmates)
837 ("redefined class %s attribute change error: NestHost class: %s replaced with: %s",
838 the_class->external_name(), the_sym->as_C_string(), scr_sym->as_C_string());
839 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
840 }
841 } else if ((the_nest_host_idx == 0) ^ (scr_nest_host_idx == 0)) {
842 const char* action_str = (the_nest_host_idx != 0) ? "removed" : "added";
843 log_info(redefine, class, nestmates)
844 ("redefined class %s attribute change error: NestHost attribute %s",
845 the_class->external_name(), action_str);
846 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
847 }
848
849 // Check whether the class NestMembers attribute has been changed.
850 return check_attribute_arrays("NestMembers",
851 the_class, scratch_class,
852 the_class->nest_members(),
853 scratch_class->nest_members());
854 }
855
856 // Return an error status if the class Record attribute was changed.
857 static jvmtiError check_record_attribute(InstanceKlass* the_class, InstanceKlass* scratch_class) {
858 // Get lists of record components.
859 Array<RecordComponent*>* the_record = the_class->record_components();
860 Array<RecordComponent*>* scr_record = scratch_class->record_components();
861 bool the_record_exists = the_record != nullptr;
862 bool scr_record_exists = scr_record != nullptr;
863
864 if (the_record_exists && scr_record_exists) {
865 int the_num_components = the_record->length();
866 int scr_num_components = scr_record->length();
867 if (the_num_components != scr_num_components) {
868 log_info(redefine, class, record)
869 ("redefined class %s attribute change error: Record num_components=%d changed to num_components=%d",
870 the_class->external_name(), the_num_components, scr_num_components);
871 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
872 }
873
874 // Compare each field in each record component.
875 ConstantPool* the_cp = the_class->constants();
876 ConstantPool* scr_cp = scratch_class->constants();
877 for (int x = 0; x < the_num_components; x++) {
878 RecordComponent* the_component = the_record->at(x);
879 RecordComponent* scr_component = scr_record->at(x);
880 const Symbol* const the_name = the_cp->symbol_at(the_component->name_index());
881 const Symbol* const scr_name = scr_cp->symbol_at(scr_component->name_index());
882 const Symbol* const the_descr = the_cp->symbol_at(the_component->descriptor_index());
883 const Symbol* const scr_descr = scr_cp->symbol_at(scr_component->descriptor_index());
884 if (the_name != scr_name || the_descr != scr_descr) {
885 log_info(redefine, class, record)
886 ("redefined class %s attribute change error: Record name_index, descriptor_index, and/or attributes_count changed",
887 the_class->external_name());
888 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
889 }
890
891 int the_gen_sig = the_component->generic_signature_index();
892 int scr_gen_sig = scr_component->generic_signature_index();
893 const Symbol* const the_gen_sig_sym = (the_gen_sig == 0 ? nullptr :
894 the_cp->symbol_at(the_component->generic_signature_index()));
895 const Symbol* const scr_gen_sig_sym = (scr_gen_sig == 0 ? nullptr :
896 scr_cp->symbol_at(scr_component->generic_signature_index()));
897 if (the_gen_sig_sym != scr_gen_sig_sym) {
898 log_info(redefine, class, record)
899 ("redefined class %s attribute change error: Record generic_signature attribute changed",
900 the_class->external_name());
901 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
902 }
903
904 // It's okay if a record component's annotations were changed.
905 }
906
907 } else if (the_record_exists ^ scr_record_exists) {
908 const char* action_str = (the_record_exists) ? "removed" : "added";
909 log_info(redefine, class, record)
910 ("redefined class %s attribute change error: Record attribute %s",
911 the_class->external_name(), action_str);
912 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
913 }
914
915 return JVMTI_ERROR_NONE;
916 }
917
918
919 static jvmtiError check_permitted_subclasses_attribute(InstanceKlass* the_class,
920 InstanceKlass* scratch_class) {
921 Thread* thread = Thread::current();
922 ResourceMark rm(thread);
923
924 // Check whether the class PermittedSubclasses attribute has been changed.
925 return check_attribute_arrays("PermittedSubclasses",
926 the_class, scratch_class,
927 the_class->permitted_subclasses(),
928 scratch_class->permitted_subclasses());
929 }
930
931 static bool can_add_or_delete(Method* m) {
932 // Compatibility mode
933 return (AllowRedefinitionToAddDeleteMethods &&
934 (m->is_private() && (m->is_static() || m->is_final())));
935 }
936
937 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions(
938 InstanceKlass* the_class,
939 InstanceKlass* scratch_class) {
940 int i;
941
942 // Check superclasses, or rather their names, since superclasses themselves can be
943 // requested to replace.
944 // Check for null superclass first since this might be java.lang.Object
945 if (the_class->super() != scratch_class->super() &&
946 (the_class->super() == nullptr || scratch_class->super() == nullptr ||
947 the_class->super()->name() !=
948 scratch_class->super()->name())) {
949 log_info(redefine, class, normalize)
950 ("redefined class %s superclass change error: superclass changed from %s to %s.",
951 the_class->external_name(),
952 the_class->super() == nullptr ? "null" : the_class->super()->external_name(),
953 scratch_class->super() == nullptr ? "null" : scratch_class->super()->external_name());
954 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
955 }
956
957 // Check if the number, names and order of directly implemented interfaces are the same.
958 // I think in principle we should just check if the sets of names of directly implemented
959 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the
960 // .java file, also changes in .class file) should not matter. However, comparing sets is
961 // technically a bit more difficult, and, more importantly, I am not sure at present that the
962 // order of interfaces does not matter on the implementation level, i.e. that the VM does not
963 // rely on it somewhere.
964 Array<InstanceKlass*>* k_interfaces = the_class->local_interfaces();
965 Array<InstanceKlass*>* k_new_interfaces = scratch_class->local_interfaces();
966 int n_intfs = k_interfaces->length();
967 if (n_intfs != k_new_interfaces->length()) {
968 log_info(redefine, class, normalize)
969 ("redefined class %s interfaces change error: number of implemented interfaces changed from %d to %d.",
970 the_class->external_name(), n_intfs, k_new_interfaces->length());
971 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
972 }
973 for (i = 0; i < n_intfs; i++) {
974 if (k_interfaces->at(i)->name() !=
975 k_new_interfaces->at(i)->name()) {
976 log_info(redefine, class, normalize)
977 ("redefined class %s interfaces change error: interface changed from %s to %s.",
978 the_class->external_name(),
979 k_interfaces->at(i)->external_name(), k_new_interfaces->at(i)->external_name());
980 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
981 }
982 }
983
984 // Check whether class is in the error init state.
985 if (the_class->is_in_error_state()) {
986 log_info(redefine, class, normalize)
987 ("redefined class %s is in error init state.", the_class->external_name());
988 // TBD #5057930: special error code is needed in 1.6
989 return JVMTI_ERROR_INVALID_CLASS;
990 }
991
992 // Check whether the nest-related attributes have been changed.
993 jvmtiError err = check_nest_attributes(the_class, scratch_class);
994 if (err != JVMTI_ERROR_NONE) {
995 return err;
996 }
997
998 // Check whether the Record attribute has been changed.
999 err = check_record_attribute(the_class, scratch_class);
1000 if (err != JVMTI_ERROR_NONE) {
1001 return err;
1002 }
1003
1004 // Check whether the PermittedSubclasses attribute has been changed.
1005 err = check_permitted_subclasses_attribute(the_class, scratch_class);
1006 if (err != JVMTI_ERROR_NONE) {
1007 return err;
1008 }
1009
1010 // Check whether class modifiers are the same.
1011 u2 old_flags = the_class->access_flags().as_class_flags();
1012 u2 new_flags = scratch_class->access_flags().as_class_flags();
1013 if (old_flags != new_flags) {
1014 log_info(redefine, class, normalize)
1015 ("redefined class %s modifiers change error: modifiers changed from %d to %d.",
1016 the_class->external_name(), old_flags, new_flags);
1017 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED;
1018 }
1019
1020 // Check if the number, names, types and order of fields declared in these classes
1021 // are the same.
1022 JavaFieldStream old_fs(the_class);
1023 JavaFieldStream new_fs(scratch_class);
1024 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) {
1025 // name and signature
1026 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index());
1027 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index());
1028 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index());
1029 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index());
1030 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) {
1031 log_info(redefine, class, normalize)
1032 ("redefined class %s fields change error: field %s %s changed to %s %s.",
1033 the_class->external_name(),
1034 sig_sym1->as_C_string(), name_sym1->as_C_string(),
1035 sig_sym2->as_C_string(), name_sym2->as_C_string());
1036 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
1037 }
1038 // offset
1039 if (old_fs.offset() != new_fs.offset()) {
1040 log_info(redefine, class, normalize)
1041 ("redefined class %s field %s change error: offset changed from %d to %d.",
1042 the_class->external_name(), name_sym2->as_C_string(), old_fs.offset(), new_fs.offset());
1043 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
1044 }
1045 // access
1046 old_flags = old_fs.access_flags().as_field_flags();
1047 new_flags = new_fs.access_flags().as_field_flags();
1048 if (old_flags != new_flags) {
1049 log_info(redefine, class, normalize)
1050 ("redefined class %s field %s change error: modifiers changed from %d to %d.",
1051 the_class->external_name(), name_sym2->as_C_string(), old_flags, new_flags);
1052 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
1053 }
1054 }
1055
1056 // If both streams aren't done then we have a differing number of
1057 // fields.
1058 if (!old_fs.done() || !new_fs.done()) {
1059 const char* action = old_fs.done() ? "added" : "deleted";
1060 log_info(redefine, class, normalize)
1061 ("redefined class %s fields change error: some fields were %s.",
1062 the_class->external_name(), action);
1063 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
1064 }
1065
1066 // Do a parallel walk through the old and new methods. Detect
1067 // cases where they match (exist in both), have been added in
1068 // the new methods, or have been deleted (exist only in the
1069 // old methods). The class file parser places methods in order
1070 // by method name, but does not order overloaded methods by
1071 // signature. In order to determine what fate befell the methods,
1072 // this code places the overloaded new methods that have matching
1073 // old methods in the same order as the old methods and places
1074 // new overloaded methods at the end of overloaded methods of
1075 // that name. The code for this order normalization is adapted
1076 // from the algorithm used in InstanceKlass::find_method().
1077 // Since we are swapping out of order entries as we find them,
1078 // we only have to search forward through the overloaded methods.
1079 // Methods which are added and have the same name as an existing
1080 // method (but different signature) will be put at the end of
1081 // the methods with that name, and the name mismatch code will
1082 // handle them.
1083 Array<Method*>* k_old_methods(the_class->methods());
1084 Array<Method*>* k_new_methods(scratch_class->methods());
1085 int n_old_methods = k_old_methods->length();
1086 int n_new_methods = k_new_methods->length();
1087 Thread* thread = Thread::current();
1088
1089 int ni = 0;
1090 int oi = 0;
1091 while (true) {
1092 Method* k_old_method;
1093 Method* k_new_method;
1094 enum { matched, added, deleted, undetermined } method_was = undetermined;
1095
1096 if (oi >= n_old_methods) {
1097 if (ni >= n_new_methods) {
1098 break; // we've looked at everything, done
1099 }
1100 // New method at the end
1101 k_new_method = k_new_methods->at(ni);
1102 method_was = added;
1103 } else if (ni >= n_new_methods) {
1104 // Old method, at the end, is deleted
1105 k_old_method = k_old_methods->at(oi);
1106 method_was = deleted;
1107 } else {
1108 // There are more methods in both the old and new lists
1109 k_old_method = k_old_methods->at(oi);
1110 k_new_method = k_new_methods->at(ni);
1111 if (k_old_method->name() != k_new_method->name()) {
1112 // Methods are sorted by method name, so a mismatch means added
1113 // or deleted
1114 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) {
1115 method_was = added;
1116 } else {
1117 method_was = deleted;
1118 }
1119 } else if (k_old_method->signature() == k_new_method->signature()) {
1120 // Both the name and signature match
1121 method_was = matched;
1122 } else {
1123 // The name matches, but the signature doesn't, which means we have to
1124 // search forward through the new overloaded methods.
1125 int nj; // outside the loop for post-loop check
1126 for (nj = ni + 1; nj < n_new_methods; nj++) {
1127 Method* m = k_new_methods->at(nj);
1128 if (k_old_method->name() != m->name()) {
1129 // reached another method name so no more overloaded methods
1130 method_was = deleted;
1131 break;
1132 }
1133 if (k_old_method->signature() == m->signature()) {
1134 // found a match so swap the methods
1135 k_new_methods->at_put(ni, m);
1136 k_new_methods->at_put(nj, k_new_method);
1137 k_new_method = m;
1138 method_was = matched;
1139 break;
1140 }
1141 }
1142
1143 if (nj >= n_new_methods) {
1144 // reached the end without a match; so method was deleted
1145 method_was = deleted;
1146 }
1147 }
1148 }
1149
1150 switch (method_was) {
1151 case matched:
1152 // methods match, be sure modifiers do too
1153 old_flags = k_old_method->access_flags().as_method_flags();
1154 new_flags = k_new_method->access_flags().as_method_flags();
1155 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) {
1156 log_info(redefine, class, normalize)
1157 ("redefined class %s method %s modifiers error: modifiers changed from %d to %d",
1158 the_class->external_name(), k_old_method->name_and_sig_as_C_string(), old_flags, new_flags);
1159 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED;
1160 }
1161 {
1162 u2 new_num = k_new_method->method_idnum();
1163 u2 old_num = k_old_method->method_idnum();
1164 if (new_num != old_num) {
1165 Method* idnum_owner = scratch_class->method_with_idnum(old_num);
1166 if (idnum_owner != nullptr) {
1167 // There is already a method assigned this idnum -- switch them
1168 // Take current and original idnum from the new_method
1169 idnum_owner->set_method_idnum(new_num);
1170 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum());
1171 }
1172 // Take current and original idnum from the old_method
1173 k_new_method->set_method_idnum(old_num);
1174 k_new_method->set_orig_method_idnum(k_old_method->orig_method_idnum());
1175 if (thread->has_pending_exception()) {
1176 return JVMTI_ERROR_OUT_OF_MEMORY;
1177 }
1178 }
1179 }
1180 log_trace(redefine, class, normalize)
1181 ("Method matched: new: %s [%d] == old: %s [%d]",
1182 k_new_method->name_and_sig_as_C_string(), ni, k_old_method->name_and_sig_as_C_string(), oi);
1183 // advance to next pair of methods
1184 ++oi;
1185 ++ni;
1186 break;
1187 case added:
1188 // method added, see if it is OK
1189 if (!can_add_or_delete(k_new_method)) {
1190 log_info(redefine, class, normalize)
1191 ("redefined class %s methods error: added method: %s [%d]",
1192 the_class->external_name(), k_new_method->name_and_sig_as_C_string(), ni);
1193 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
1194 }
1195 {
1196 u2 num = the_class->next_method_idnum();
1197 if (num == ConstMethod::UNSET_IDNUM) {
1198 // cannot add any more methods
1199 log_info(redefine, class, normalize)
1200 ("redefined class %s methods error: can't create ID for new method %s [%d]",
1201 the_class->external_name(), k_new_method->name_and_sig_as_C_string(), ni);
1202 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
1203 }
1204 u2 new_num = k_new_method->method_idnum();
1205 Method* idnum_owner = scratch_class->method_with_idnum(num);
1206 if (idnum_owner != nullptr) {
1207 // There is already a method assigned this idnum -- switch them
1208 // Take current and original idnum from the new_method
1209 idnum_owner->set_method_idnum(new_num);
1210 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum());
1211 }
1212 k_new_method->set_method_idnum(num);
1213 k_new_method->set_orig_method_idnum(num);
1214 if (thread->has_pending_exception()) {
1215 return JVMTI_ERROR_OUT_OF_MEMORY;
1216 }
1217 }
1218 log_trace(redefine, class, normalize)
1219 ("Method added: new: %s [%d]", k_new_method->name_and_sig_as_C_string(), ni);
1220 ++ni; // advance to next new method
1221 break;
1222 case deleted:
1223 // method deleted, see if it is OK
1224 if (!can_add_or_delete(k_old_method)) {
1225 log_info(redefine, class, normalize)
1226 ("redefined class %s methods error: deleted method %s [%d]",
1227 the_class->external_name(), k_old_method->name_and_sig_as_C_string(), oi);
1228 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED;
1229 }
1230 log_trace(redefine, class, normalize)
1231 ("Method deleted: old: %s [%d]", k_old_method->name_and_sig_as_C_string(), oi);
1232 ++oi; // advance to next old method
1233 break;
1234 default:
1235 ShouldNotReachHere();
1236 }
1237 }
1238
1239 return JVMTI_ERROR_NONE;
1240 }
1241
1242
1243 // Find new constant pool index value for old constant pool index value
1244 // by searching the index map. Returns zero (0) if there is no mapped
1245 // value for the old constant pool index.
1246 u2 VM_RedefineClasses::find_new_index(int old_index) {
1247 if (_index_map_count == 0) {
1248 // map is empty so nothing can be found
1249 return 0;
1250 }
1251
1252 if (old_index < 1 || old_index >= _index_map_p->length()) {
1253 // The old_index is out of range so it is not mapped. This should
1254 // not happen in regular constant pool merging use, but it can
1255 // happen if a corrupt annotation is processed.
1256 return 0;
1257 }
1258
1259 int value = _index_map_p->at(old_index);
1260 if (value == -1) {
1261 // the old_index is not mapped
1262 return 0;
1263 }
1264
1265 // constant pool indices are u2, unless the merged constant pool overflows which
1266 // we don't check for.
1267 return checked_cast<u2>(value);
1268 } // end find_new_index()
1269
1270
1271 // Find new bootstrap specifier index value for old bootstrap specifier index
1272 // value by searching the index map. Returns unused index (-1) if there is
1273 // no mapped value for the old bootstrap specifier index.
1274 int VM_RedefineClasses::find_new_bsm_index(int old_index) {
1275 if (_bsm_index_map_count == 0) {
1276 // map is empty so nothing can be found
1277 return -1;
1278 }
1279
1280 if (old_index == -1 || old_index >= _bsm_index_map_p->length()) {
1281 // The old_index is out of range so it is not mapped.
1282 // This should not happen in regular constant pool merging use.
1283 return -1;
1284 }
1285
1286 int value = _bsm_index_map_p->at(old_index);
1287 if (value == -1) {
1288 // the old_index is not mapped
1289 return -1;
1290 }
1291
1292 return value;
1293 } // end find_new_bsm_index()
1294
1295
1296 // The bug 6214132 caused the verification to fail.
1297 // 1. What's done in RedefineClasses() before verification:
1298 // a) A reference to the class being redefined (_the_class) and a
1299 // reference to new version of the class (_scratch_class) are
1300 // saved here for use during the bytecode verification phase of
1301 // RedefineClasses.
1302 // b) The _java_mirror field from _the_class is copied to the
1303 // _java_mirror field in _scratch_class. This means that a jclass
1304 // returned for _the_class or _scratch_class will refer to the
1305 // same Java mirror. The verifier will see the "one true mirror"
1306 // for the class being verified.
1307 // 2. See comments in JvmtiThreadState for what is done during verification.
1308
1309 class RedefineVerifyMark : public StackObj {
1310 private:
1311 JvmtiThreadState* _state;
1312 InstanceKlass* _scratch_class;
1313 OopHandle _scratch_mirror;
1314
1315 public:
1316
1317 RedefineVerifyMark(InstanceKlass* the_class, InstanceKlass* scratch_class,
1318 JvmtiThreadState* state) : _state(state), _scratch_class(scratch_class)
1319 {
1320 _state->set_class_versions_map(the_class, scratch_class);
1321 _scratch_mirror = the_class->java_mirror_handle(); // this is a copy that is swapped
1322 _scratch_class->swap_java_mirror_handle(_scratch_mirror);
1323 }
1324
1325 ~RedefineVerifyMark() {
1326 // Restore the scratch class's mirror, so when scratch_class is removed
1327 // the correct mirror pointing to it can be cleared.
1328 _scratch_class->swap_java_mirror_handle(_scratch_mirror);
1329 _state->clear_class_versions_map();
1330 }
1331 };
1332
1333
1334 jvmtiError VM_RedefineClasses::load_new_class_versions() {
1335
1336 // For consistency allocate memory using os::malloc wrapper.
1337 _scratch_classes = (InstanceKlass**)
1338 os::malloc(sizeof(InstanceKlass*) * _class_count, mtClass);
1339 if (_scratch_classes == nullptr) {
1340 return JVMTI_ERROR_OUT_OF_MEMORY;
1341 }
1342 // Zero initialize the _scratch_classes array.
1343 for (int i = 0; i < _class_count; i++) {
1344 _scratch_classes[i] = nullptr;
1345 }
1346
1347 JavaThread* current = JavaThread::current();
1348 ResourceMark rm(current);
1349
1350 JvmtiThreadState *state = JvmtiThreadState::state_for(current);
1351 // state can only be null if the current thread is exiting which
1352 // should not happen since we're trying to do a RedefineClasses
1353 guarantee(state != nullptr, "exiting thread calling load_new_class_versions");
1354 for (int i = 0; i < _class_count; i++) {
1355 // Create HandleMark so that any handles created while loading new class
1356 // versions are deleted. Constant pools are deallocated while merging
1357 // constant pools
1358 HandleMark hm(current);
1359 InstanceKlass* the_class = get_ik(_class_defs[i].klass);
1360 physical_memory_size_type avail_mem = 0;
1361 // Return value ignored - defaulting to 0 on failure.
1362 (void)os::available_memory(avail_mem);
1363 log_debug(redefine, class, load)
1364 ("loading name=%s kind=%d (avail_mem=" PHYS_MEM_TYPE_FORMAT "K)",
1365 the_class->external_name(), _class_load_kind, avail_mem >> 10);
1366
1367 ClassFileStream st((u1*)_class_defs[i].class_bytes,
1368 _class_defs[i].class_byte_count,
1369 "__VM_RedefineClasses__");
1370
1371 // Set redefined class handle in JvmtiThreadState class.
1372 // This redefined class is sent to agent event handler for class file
1373 // load hook event.
1374 state->set_class_being_redefined(the_class, _class_load_kind);
1375
1376 JavaThread* THREAD = current; // For exception macros.
1377 ExceptionMark em(THREAD);
1378 Handle protection_domain(THREAD, the_class->protection_domain());
1379 ClassLoadInfo cl_info(protection_domain);
1380 // Parse and create a class from the bytes, but this class isn't added
1381 // to the dictionary, so do not call resolve_from_stream.
1382 InstanceKlass* scratch_class = KlassFactory::create_from_stream(&st,
1383 the_class->name(),
1384 the_class->class_loader_data(),
1385 cl_info,
1386 THREAD);
1387
1388 // Clear class_being_redefined just to be sure.
1389 state->clear_class_being_redefined();
1390
1391 // TODO: if this is retransform, and nothing changed we can skip it
1392
1393 // Need to clean up allocated InstanceKlass if there's an error so assign
1394 // the result here. Caller deallocates all the scratch classes in case of
1395 // an error.
1396 _scratch_classes[i] = scratch_class;
1397
1398 if (HAS_PENDING_EXCEPTION) {
1399 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1400 log_info(redefine, class, load, exceptions)("create_from_stream exception: '%s'", ex_name->as_C_string());
1401 CLEAR_PENDING_EXCEPTION;
1402
1403 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) {
1404 return JVMTI_ERROR_UNSUPPORTED_VERSION;
1405 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) {
1406 return JVMTI_ERROR_INVALID_CLASS_FORMAT;
1407 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) {
1408 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION;
1409 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
1410 // The message will be "XXX (wrong name: YYY)"
1411 return JVMTI_ERROR_NAMES_DONT_MATCH;
1412 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1413 return JVMTI_ERROR_OUT_OF_MEMORY;
1414 } else { // Just in case more exceptions can be thrown..
1415 return JVMTI_ERROR_FAILS_VERIFICATION;
1416 }
1417 }
1418
1419 // Ensure class is linked before redefine
1420 if (!the_class->is_linked()) {
1421 the_class->link_class(THREAD);
1422 if (HAS_PENDING_EXCEPTION) {
1423 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1424 oop message = java_lang_Throwable::message(PENDING_EXCEPTION);
1425 if (message != nullptr) {
1426 char* ex_msg = java_lang_String::as_utf8_string(message);
1427 log_info(redefine, class, load, exceptions)("link_class exception: '%s %s'",
1428 ex_name->as_C_string(), ex_msg);
1429 } else {
1430 log_info(redefine, class, load, exceptions)("link_class exception: '%s'",
1431 ex_name->as_C_string());
1432 }
1433 CLEAR_PENDING_EXCEPTION;
1434 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1435 return JVMTI_ERROR_OUT_OF_MEMORY;
1436 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
1437 return JVMTI_ERROR_INVALID_CLASS;
1438 } else {
1439 return JVMTI_ERROR_INTERNAL;
1440 }
1441 }
1442 }
1443
1444 // Do the validity checks in compare_and_normalize_class_versions()
1445 // before verifying the byte codes. By doing these checks first, we
1446 // limit the number of functions that require redirection from
1447 // the_class to scratch_class. In particular, we don't have to
1448 // modify JNI GetSuperclass() and thus won't change its performance.
1449 jvmtiError res = compare_and_normalize_class_versions(the_class,
1450 scratch_class);
1451 if (res != JVMTI_ERROR_NONE) {
1452 return res;
1453 }
1454
1455 // verify what the caller passed us
1456 {
1457 // The bug 6214132 caused the verification to fail.
1458 // Information about the_class and scratch_class is temporarily
1459 // recorded into jvmtiThreadState. This data is used to redirect
1460 // the_class to scratch_class in the JVM_* functions called by the
1461 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed
1462 // description.
1463 RedefineVerifyMark rvm(the_class, scratch_class, state);
1464 Verifier::verify(scratch_class, true, THREAD);
1465 }
1466
1467 if (HAS_PENDING_EXCEPTION) {
1468 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1469 log_info(redefine, class, load, exceptions)("verify_byte_codes exception: '%s'", ex_name->as_C_string());
1470 CLEAR_PENDING_EXCEPTION;
1471 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1472 return JVMTI_ERROR_OUT_OF_MEMORY;
1473 } else {
1474 // tell the caller the bytecodes are bad
1475 return JVMTI_ERROR_FAILS_VERIFICATION;
1476 }
1477 }
1478
1479 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD);
1480 if (HAS_PENDING_EXCEPTION) {
1481 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1482 log_info(redefine, class, load, exceptions)("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string());
1483 CLEAR_PENDING_EXCEPTION;
1484 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1485 return JVMTI_ERROR_OUT_OF_MEMORY;
1486 } else {
1487 return JVMTI_ERROR_INTERNAL;
1488 }
1489 } else if (res != JVMTI_ERROR_NONE) {
1490 return res;
1491 }
1492
1493 #ifdef ASSERT
1494 {
1495 // verify what we have done during constant pool merging
1496 {
1497 RedefineVerifyMark rvm(the_class, scratch_class, state);
1498 Verifier::verify(scratch_class, true, THREAD);
1499 }
1500
1501 if (HAS_PENDING_EXCEPTION) {
1502 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1503 log_info(redefine, class, load, exceptions)
1504 ("verify_byte_codes post merge-CP exception: '%s'", ex_name->as_C_string());
1505 CLEAR_PENDING_EXCEPTION;
1506 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1507 return JVMTI_ERROR_OUT_OF_MEMORY;
1508 } else {
1509 // tell the caller that constant pool merging screwed up
1510 return JVMTI_ERROR_INTERNAL;
1511 }
1512 }
1513 }
1514 #endif // ASSERT
1515
1516 Rewriter::rewrite(scratch_class, THREAD);
1517 if (!HAS_PENDING_EXCEPTION) {
1518 scratch_class->link_methods(THREAD);
1519 }
1520 if (HAS_PENDING_EXCEPTION) {
1521 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1522 log_info(redefine, class, load, exceptions)
1523 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string());
1524 CLEAR_PENDING_EXCEPTION;
1525 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1526 return JVMTI_ERROR_OUT_OF_MEMORY;
1527 } else {
1528 return JVMTI_ERROR_INTERNAL;
1529 }
1530 }
1531 // Return value ignored - defaulting to 0 on failure.
1532 (void)os::available_memory(avail_mem);
1533 log_debug(redefine, class, load)
1534 ("loaded name=%s (avail_mem=" PHYS_MEM_TYPE_FORMAT "K)", the_class->external_name(), avail_mem >> 10);
1535 }
1536
1537 return JVMTI_ERROR_NONE;
1538 }
1539
1540
1541 // Map old_index to new_index as needed. scratch_cp is only needed
1542 // for log calls.
1543 void VM_RedefineClasses::map_index(const constantPoolHandle& scratch_cp,
1544 int old_index, int new_index) {
1545 if (find_new_index(old_index) != 0) {
1546 // old_index is already mapped
1547 return;
1548 }
1549
1550 if (old_index == new_index) {
1551 // no mapping is needed
1552 return;
1553 }
1554
1555 _index_map_p->at_put(old_index, new_index);
1556 _index_map_count++;
1557
1558 log_trace(redefine, class, constantpool)
1559 ("mapped tag %d at index %d to %d", scratch_cp->tag_at(old_index).value(), old_index, new_index);
1560 } // end map_index()
1561
1562
1563 // Map old_index to new_index as needed.
1564 void VM_RedefineClasses::map_bsm_index(int old_index, int new_index) {
1565 if (old_index == new_index) {
1566 // no mapping is needed
1567 return;
1568 }
1569 _bsm_index_map_p->at_put(old_index, new_index);
1570 _bsm_index_map_count++;
1571 log_trace(redefine, class, constantpool)("mapped bootstrap specifier at index %d to %d", old_index, new_index);
1572 } // end map_bsm_index()
1573
1574
1575 // Merge old_cp and scratch_cp and return the results of the merge via
1576 // merge_cp_p. The number of entries in merge_cp_p is returned via
1577 // merge_cp_length_p. The entries in old_cp occupy the same locations
1578 // in merge_cp_p. Also creates a map of indices from entries in
1579 // scratch_cp to the corresponding entry in merge_cp_p. Index map
1580 // entries are only created for entries in scratch_cp that occupy a
1581 // different location in merged_cp_p.
1582 bool VM_RedefineClasses::merge_constant_pools(const constantPoolHandle& old_cp,
1583 const constantPoolHandle& scratch_cp, constantPoolHandle& merge_cp_p,
1584 int& merge_cp_length_p, TRAPS) {
1585
1586 // Worst case we need old_cp->length() + scratch_cp()->length(),
1587 // but the caller might be smart so make sure we have at least
1588 // the minimum.
1589 if (merge_cp_p->length() < old_cp->length()) {
1590 assert(false, "merge area too small");
1591 return false; // robustness
1592 }
1593
1594 log_info(redefine, class, constantpool)("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(), scratch_cp->length());
1595
1596 {
1597 // Pass 0:
1598 // The old_cp is copied to *merge_cp_p; this means that any code
1599 // using old_cp does not have to change. This work looks like a
1600 // perfect fit for ConstantPool*::copy_cp_to(), but we need to
1601 // handle one special case:
1602 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass
1603 // This will make verification happy.
1604
1605 int old_i; // index into old_cp
1606
1607 // index zero (0) is not used in constantPools
1608 for (old_i = 1; old_i < old_cp->length(); old_i++) {
1609 // leave debugging crumb
1610 jbyte old_tag = old_cp->tag_at(old_i).value();
1611 switch (old_tag) {
1612 case JVM_CONSTANT_Class:
1613 case JVM_CONSTANT_UnresolvedClass:
1614 // revert the copy to JVM_CONSTANT_UnresolvedClass
1615 // May be resolving while calling this so do the same for
1616 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition)
1617 merge_cp_p->temp_unresolved_klass_at_put(old_i,
1618 old_cp->klass_name_index_at(old_i));
1619 break;
1620
1621 case JVM_CONSTANT_Double:
1622 case JVM_CONSTANT_Long:
1623 // just copy the entry to merge_cp_p, but double and long take
1624 // two constant pool entries
1625 ConstantPool::copy_entry_to(old_cp, old_i, merge_cp_p, old_i);
1626 old_i++;
1627 break;
1628
1629 default:
1630 // just copy the entry to merge_cp_p
1631 ConstantPool::copy_entry_to(old_cp, old_i, merge_cp_p, old_i);
1632 break;
1633 }
1634 } // end for each old_cp entry
1635
1636 ConstantPool::copy_bsm_entries(old_cp, merge_cp_p, CHECK_false);
1637 _bsmae_iter = merge_cp_p->start_extension(scratch_cp, CHECK_false);
1638
1639 // We don't need to sanity check that *merge_cp_length_p is within
1640 // *merge_cp_p bounds since we have the minimum on-entry check above.
1641 merge_cp_length_p = old_i;
1642 }
1643
1644 // merge_cp_len should be the same as old_cp->length() at this point
1645 // so this trace message is really a "warm-and-breathing" message.
1646 log_debug(redefine, class, constantpool)("after pass 0: merge_cp_len=%d", merge_cp_length_p);
1647
1648 int scratch_i; // index into scratch_cp
1649 {
1650 // Pass 1a:
1651 // Compare scratch_cp entries to the old_cp entries that we have
1652 // already copied to *merge_cp_p. In this pass, we are eliminating
1653 // exact duplicates (matching entry at same index) so we only
1654 // compare entries in the common indice range.
1655 int increment = 1;
1656 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length());
1657 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) {
1658 switch (scratch_cp->tag_at(scratch_i).value()) {
1659 case JVM_CONSTANT_Double:
1660 case JVM_CONSTANT_Long:
1661 // double and long take two constant pool entries
1662 increment = 2;
1663 break;
1664
1665 default:
1666 increment = 1;
1667 break;
1668 }
1669
1670 bool match = scratch_cp->compare_entry_to(scratch_i, merge_cp_p, scratch_i);
1671 if (match) {
1672 // found a match at the same index so nothing more to do
1673 continue;
1674 }
1675
1676 int found_i = scratch_cp->find_matching_entry(scratch_i, merge_cp_p);
1677 if (found_i != 0) {
1678 guarantee(found_i != scratch_i,
1679 "compare_entry_to() and find_matching_entry() do not agree");
1680
1681 // Found a matching entry somewhere else in *merge_cp_p so
1682 // just need a mapping entry.
1683 map_index(scratch_cp, scratch_i, found_i);
1684 continue;
1685 }
1686
1687 // No match found so we have to append this entry and any unique
1688 // referenced entries to merge_cp_p.
1689 append_entry(scratch_cp, scratch_i, &merge_cp_p, &merge_cp_length_p);
1690 }
1691 }
1692
1693 log_debug(redefine, class, constantpool)
1694 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1695 merge_cp_length_p, scratch_i, _index_map_count);
1696
1697 if (scratch_i < scratch_cp->length()) {
1698 // Pass 1b:
1699 // old_cp is smaller than scratch_cp so there are entries in
1700 // scratch_cp that we have not yet processed. We take care of
1701 // those now.
1702 int increment = 1;
1703 for (; scratch_i < scratch_cp->length(); scratch_i += increment) {
1704 switch (scratch_cp->tag_at(scratch_i).value()) {
1705 case JVM_CONSTANT_Double:
1706 case JVM_CONSTANT_Long:
1707 // double and long take two constant pool entries
1708 increment = 2;
1709 break;
1710
1711 default:
1712 increment = 1;
1713 break;
1714 }
1715
1716 int found_i =
1717 scratch_cp->find_matching_entry(scratch_i, merge_cp_p);
1718 if (found_i != 0) {
1719 // Found a matching entry somewhere else in merge_cp_p so
1720 // just need a mapping entry.
1721 map_index(scratch_cp, scratch_i, found_i);
1722 continue;
1723 }
1724
1725 // No match found so we have to append this entry and any unique
1726 // referenced entries to merge_cp_p.
1727 append_entry(scratch_cp, scratch_i, &merge_cp_p, &merge_cp_length_p);
1728 }
1729
1730 log_debug(redefine, class, constantpool)
1731 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1732 merge_cp_length_p, scratch_i, _index_map_count);
1733 }
1734 finalize_bsm_entries_merge(merge_cp_p, CHECK_false);
1735
1736 return true;
1737 } // end merge_constant_pools()
1738
1739
1740 // Scoped object to clean up the constant pool(s) created for merging
1741 class MergeCPCleaner {
1742 ClassLoaderData* _loader_data;
1743 ConstantPool* _cp;
1744 ConstantPool* _scratch_cp;
1745 public:
1746 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) :
1747 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(nullptr) {}
1748 ~MergeCPCleaner() {
1749 _loader_data->add_to_deallocate_list(_cp);
1750 if (_scratch_cp != nullptr) {
1751 _loader_data->add_to_deallocate_list(_scratch_cp);
1752 }
1753 }
1754 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; }
1755 };
1756
1757 // Merge constant pools between the_class and scratch_class and
1758 // potentially rewrite bytecodes in scratch_class to use the merged
1759 // constant pool.
1760 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite(
1761 InstanceKlass* the_class, InstanceKlass* scratch_class,
1762 TRAPS) {
1763 // worst case merged constant pool length is old and new combined
1764 int merge_cp_length = the_class->constants()->length()
1765 + scratch_class->constants()->length();
1766
1767 // Constant pools are not easily reused so we allocate a new one
1768 // each time.
1769 // merge_cp is created unsafe for concurrent GC processing. It
1770 // should be marked safe before discarding it. Even though
1771 // garbage, if it crosses a card boundary, it may be scanned
1772 // in order to find the start of the first complete object on the card.
1773 ClassLoaderData* loader_data = the_class->class_loader_data();
1774 ConstantPool* merge_cp_oop =
1775 ConstantPool::allocate(loader_data,
1776 merge_cp_length,
1777 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1778 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop);
1779
1780 HandleMark hm(THREAD); // make sure handles are cleared before
1781 // MergeCPCleaner clears out merge_cp_oop
1782 constantPoolHandle merge_cp(THREAD, merge_cp_oop);
1783
1784 // Get constants() from the old class because it could have been rewritten
1785 // while we were at a safepoint allocating a new constant pool.
1786 constantPoolHandle old_cp(THREAD, the_class->constants());
1787 constantPoolHandle scratch_cp(THREAD, scratch_class->constants());
1788
1789 // If the length changed, the class was redefined out from under us. Return
1790 // an error.
1791 if (merge_cp_length != the_class->constants()->length()
1792 + scratch_class->constants()->length()) {
1793 return JVMTI_ERROR_INTERNAL;
1794 }
1795
1796 // Update the version number of the constant pools (may keep scratch_cp)
1797 merge_cp->increment_and_save_version(old_cp->version());
1798 scratch_cp->increment_and_save_version(old_cp->version());
1799
1800 ResourceMark rm(THREAD);
1801 _index_map_count = 0;
1802 _index_map_p = new intArray(scratch_cp->length(), scratch_cp->length(), -1);
1803
1804 _bsm_index_map_count = 0;
1805 int bsm_data_len = scratch_cp->bsm_entries().array_length();
1806 _bsm_index_map_p = new intArray(bsm_data_len, bsm_data_len, -1);
1807
1808 // reference to the cp holder is needed for reallocating the BSM attribute
1809 merge_cp->set_pool_holder(scratch_class);
1810 bool result = merge_constant_pools(old_cp, scratch_cp, merge_cp,
1811 merge_cp_length, THREAD);
1812 merge_cp->set_pool_holder(nullptr);
1813
1814 if (!result) {
1815 // The merge can fail due to memory allocation failure or due
1816 // to robustness checks.
1817 return JVMTI_ERROR_INTERNAL;
1818 }
1819
1820 // ensure merged constant pool size does not overflow u2
1821 if (merge_cp_length > 0xFFFF) {
1822 log_warning(redefine, class, constantpool)("Merged constant pool overflow: %d entries", merge_cp_length);
1823 return JVMTI_ERROR_INTERNAL;
1824 }
1825
1826 // Set dynamic constants attribute from the original CP.
1827 if (old_cp->has_dynamic_constant()) {
1828 scratch_cp->set_has_dynamic_constant();
1829 }
1830
1831 log_info(redefine, class, constantpool)("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count);
1832
1833 if (_index_map_count == 0) {
1834 // there is nothing to map between the new and merged constant pools
1835
1836 // Copy attributes from scratch_cp to merge_cp
1837 merge_cp->copy_fields(scratch_cp());
1838
1839 if (old_cp->length() == scratch_cp->length()) {
1840 // The old and new constant pools are the same length and the
1841 // index map is empty. This means that the three constant pools
1842 // are equivalent (but not the same). Unfortunately, the new
1843 // constant pool has not gone through link resolution nor have
1844 // the new class bytecodes gone through constant pool cache
1845 // rewriting so we can't use the old constant pool with the new
1846 // class.
1847
1848 // toss the merged constant pool at return
1849 } else if (old_cp->length() < scratch_cp->length()) {
1850 // The old constant pool has fewer entries than the new constant
1851 // pool and the index map is empty. This means the new constant
1852 // pool is a superset of the old constant pool. However, the old
1853 // class bytecodes have already gone through constant pool cache
1854 // rewriting so we can't use the new constant pool with the old
1855 // class.
1856
1857 // toss the merged constant pool at return
1858 } else {
1859 // The old constant pool has more entries than the new constant
1860 // pool and the index map is empty. This means that both the old
1861 // and merged constant pools are supersets of the new constant
1862 // pool.
1863
1864 // Replace the new constant pool with a shrunken copy of the
1865 // merged constant pool
1866 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1867 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1868 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1869 // It can't be cleaned up while there are handles to it.
1870 cp_cleaner.add_scratch_cp(scratch_cp());
1871 }
1872 } else {
1873 if (log_is_enabled(Trace, redefine, class, constantpool)) {
1874 // don't want to loop unless we are tracing
1875 int count = 0;
1876 for (int i = 1; i < _index_map_p->length(); i++) {
1877 int value = _index_map_p->at(i);
1878
1879 if (value != -1) {
1880 log_trace(redefine, class, constantpool)("index_map[%d]: old=%d new=%d", count, i, value);
1881 count++;
1882 }
1883 }
1884 }
1885
1886 // We have entries mapped between the new and merged constant pools
1887 // so we have to rewrite some constant pool references.
1888 if (!rewrite_cp_refs(scratch_class)) {
1889 return JVMTI_ERROR_INTERNAL;
1890 }
1891
1892 // Copy attributes from scratch_cp to merge_cp (should be done after rewrite_cp_refs())
1893 merge_cp->copy_fields(scratch_cp());
1894
1895 // Replace the new constant pool with a shrunken copy of the
1896 // merged constant pool so now the rewritten bytecodes have
1897 // valid references; the previous new constant pool will get
1898 // GCed.
1899 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1900 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1901 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1902 // It can't be cleaned up while there are handles to it.
1903 cp_cleaner.add_scratch_cp(scratch_cp());
1904 }
1905
1906 return JVMTI_ERROR_NONE;
1907 } // end merge_cp_and_rewrite()
1908
1909
1910 // Rewrite constant pool references in klass scratch_class.
1911 bool VM_RedefineClasses::rewrite_cp_refs(InstanceKlass* scratch_class) {
1912
1913 // rewrite constant pool references in the nest attributes:
1914 if (!rewrite_cp_refs_in_nest_attributes(scratch_class)) {
1915 // propagate failure back to caller
1916 return false;
1917 }
1918
1919 // rewrite constant pool references in the Record attribute:
1920 if (!rewrite_cp_refs_in_record_attribute(scratch_class)) {
1921 // propagate failure back to caller
1922 return false;
1923 }
1924
1925 // rewrite constant pool references in the PermittedSubclasses attribute:
1926 if (!rewrite_cp_refs_in_permitted_subclasses_attribute(scratch_class)) {
1927 // propagate failure back to caller
1928 return false;
1929 }
1930
1931 // rewrite constant pool references in the methods:
1932 if (!rewrite_cp_refs_in_methods(scratch_class)) {
1933 // propagate failure back to caller
1934 return false;
1935 }
1936
1937 // rewrite constant pool references in the class_annotations:
1938 if (!rewrite_cp_refs_in_class_annotations(scratch_class)) {
1939 // propagate failure back to caller
1940 return false;
1941 }
1942
1943 // rewrite constant pool references in the fields_annotations:
1944 if (!rewrite_cp_refs_in_fields_annotations(scratch_class)) {
1945 // propagate failure back to caller
1946 return false;
1947 }
1948
1949 // rewrite constant pool references in the methods_annotations:
1950 if (!rewrite_cp_refs_in_methods_annotations(scratch_class)) {
1951 // propagate failure back to caller
1952 return false;
1953 }
1954
1955 // rewrite constant pool references in the methods_parameter_annotations:
1956 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class)) {
1957 // propagate failure back to caller
1958 return false;
1959 }
1960
1961 // rewrite constant pool references in the methods_default_annotations:
1962 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class)) {
1963 // propagate failure back to caller
1964 return false;
1965 }
1966
1967 // rewrite constant pool references in the class_type_annotations:
1968 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class)) {
1969 // propagate failure back to caller
1970 return false;
1971 }
1972
1973 // rewrite constant pool references in the fields_type_annotations:
1974 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class)) {
1975 // propagate failure back to caller
1976 return false;
1977 }
1978
1979 // rewrite constant pool references in the methods_type_annotations:
1980 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class)) {
1981 // propagate failure back to caller
1982 return false;
1983 }
1984
1985 // There can be type annotations in the Code part of a method_info attribute.
1986 // These annotations are not accessible, even by reflection.
1987 // Currently they are not even parsed by the ClassFileParser.
1988 // If runtime access is added they will also need to be rewritten.
1989
1990 // rewrite source file name index:
1991 u2 source_file_name_idx = scratch_class->source_file_name_index();
1992 if (source_file_name_idx != 0) {
1993 u2 new_source_file_name_idx = find_new_index(source_file_name_idx);
1994 if (new_source_file_name_idx != 0) {
1995 scratch_class->set_source_file_name_index(new_source_file_name_idx);
1996 }
1997 }
1998
1999 // rewrite class generic signature index:
2000 u2 generic_signature_index = scratch_class->generic_signature_index();
2001 if (generic_signature_index != 0) {
2002 u2 new_generic_signature_index = find_new_index(generic_signature_index);
2003 if (new_generic_signature_index != 0) {
2004 scratch_class->set_generic_signature_index(new_generic_signature_index);
2005 }
2006 }
2007
2008 return true;
2009 } // end rewrite_cp_refs()
2010
2011 // Rewrite constant pool references in the NestHost and NestMembers attributes.
2012 bool VM_RedefineClasses::rewrite_cp_refs_in_nest_attributes(
2013 InstanceKlass* scratch_class) {
2014
2015 u2 cp_index = scratch_class->nest_host_index();
2016 if (cp_index != 0) {
2017 scratch_class->set_nest_host_index(find_new_index(cp_index));
2018 }
2019 Array<u2>* nest_members = scratch_class->nest_members();
2020 for (int i = 0; i < nest_members->length(); i++) {
2021 u2 cp_index = nest_members->at(i);
2022 nest_members->at_put(i, find_new_index(cp_index));
2023 }
2024 return true;
2025 }
2026
2027 // Rewrite constant pool references in the Record attribute.
2028 bool VM_RedefineClasses::rewrite_cp_refs_in_record_attribute(InstanceKlass* scratch_class) {
2029 Array<RecordComponent*>* components = scratch_class->record_components();
2030 if (components != nullptr) {
2031 for (int i = 0; i < components->length(); i++) {
2032 RecordComponent* component = components->at(i);
2033 u2 cp_index = component->name_index();
2034 component->set_name_index(find_new_index(cp_index));
2035 cp_index = component->descriptor_index();
2036 component->set_descriptor_index(find_new_index(cp_index));
2037 cp_index = component->generic_signature_index();
2038 if (cp_index != 0) {
2039 component->set_generic_signature_index(find_new_index(cp_index));
2040 }
2041
2042 AnnotationArray* annotations = component->annotations();
2043 if (annotations != nullptr && annotations->length() != 0) {
2044 int byte_i = 0; // byte index into annotations
2045 if (!rewrite_cp_refs_in_annotations_typeArray(annotations, byte_i)) {
2046 log_debug(redefine, class, annotation)("bad record_component_annotations at %d", i);
2047 // propagate failure back to caller
2048 return false;
2049 }
2050 }
2051
2052 AnnotationArray* type_annotations = component->type_annotations();
2053 if (type_annotations != nullptr && type_annotations->length() != 0) {
2054 int byte_i = 0; // byte index into annotations
2055 if (!rewrite_cp_refs_in_type_annotations_typeArray(type_annotations, byte_i, "record_info")) {
2056 log_debug(redefine, class, annotation)("bad record_component_type_annotations at %d", i);
2057 // propagate failure back to caller
2058 return false;
2059 }
2060 }
2061 }
2062 }
2063 return true;
2064 }
2065
2066 // Rewrite constant pool references in the PermittedSubclasses attribute.
2067 bool VM_RedefineClasses::rewrite_cp_refs_in_permitted_subclasses_attribute(
2068 InstanceKlass* scratch_class) {
2069
2070 Array<u2>* permitted_subclasses = scratch_class->permitted_subclasses();
2071 assert(permitted_subclasses != nullptr, "unexpected null permitted_subclasses");
2072 for (int i = 0; i < permitted_subclasses->length(); i++) {
2073 u2 cp_index = permitted_subclasses->at(i);
2074 permitted_subclasses->at_put(i, find_new_index(cp_index));
2075 }
2076 return true;
2077 }
2078
2079 // Rewrite constant pool references in the methods.
2080 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(InstanceKlass* scratch_class) {
2081
2082 Array<Method*>* methods = scratch_class->methods();
2083
2084 if (methods == nullptr || methods->length() == 0) {
2085 // no methods so nothing to do
2086 return true;
2087 }
2088
2089 JavaThread* THREAD = JavaThread::current(); // For exception macros.
2090 ExceptionMark em(THREAD);
2091
2092 // rewrite constant pool references in the methods:
2093 for (int i = methods->length() - 1; i >= 0; i--) {
2094 methodHandle method(THREAD, methods->at(i));
2095 methodHandle new_method;
2096 rewrite_cp_refs_in_method(method, &new_method, THREAD);
2097 if (!new_method.is_null()) {
2098 // the method has been replaced so save the new method version
2099 // even in the case of an exception. original method is on the
2100 // deallocation list.
2101 methods->at_put(i, new_method());
2102 }
2103 if (HAS_PENDING_EXCEPTION) {
2104 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
2105 log_info(redefine, class, load, exceptions)("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string());
2106 // Need to clear pending exception here as the super caller sets
2107 // the JVMTI_ERROR_INTERNAL if the returned value is false.
2108 CLEAR_PENDING_EXCEPTION;
2109 return false;
2110 }
2111 }
2112
2113 return true;
2114 }
2115
2116
2117 // Rewrite constant pool references in the specific method. This code
2118 // was adapted from Rewriter::rewrite_method().
2119 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method,
2120 methodHandle *new_method_p, TRAPS) {
2121
2122 *new_method_p = methodHandle(); // default is no new method
2123
2124 // We cache a pointer to the bytecodes here in code_base. If GC
2125 // moves the Method*, then the bytecodes will also move which
2126 // will likely cause a crash. We create a NoSafepointVerifier
2127 // object to detect whether we pass a possible safepoint in this
2128 // code block.
2129 NoSafepointVerifier nsv;
2130
2131 // Bytecodes and their length
2132 address code_base = method->code_base();
2133 int code_length = method->code_size();
2134
2135 int bc_length;
2136 for (int bci = 0; bci < code_length; bci += bc_length) {
2137 address bcp = code_base + bci;
2138 Bytecodes::Code c = (Bytecodes::Code)(*bcp);
2139
2140 bc_length = Bytecodes::length_for(c);
2141 if (bc_length == 0) {
2142 // More complicated bytecodes report a length of zero so
2143 // we have to try again a slightly different way.
2144 bc_length = Bytecodes::length_at(method(), bcp);
2145 }
2146
2147 assert(bc_length != 0, "impossible bytecode length");
2148
2149 switch (c) {
2150 case Bytecodes::_ldc:
2151 {
2152 u1 cp_index = *(bcp + 1);
2153 u2 new_index = find_new_index(cp_index);
2154
2155 if (StressLdcRewrite && new_index == 0) {
2156 // If we are stressing ldc -> ldc_w rewriting, then we
2157 // always need a new_index value.
2158 new_index = cp_index;
2159 }
2160 if (new_index != 0) {
2161 // the original index is mapped so we have more work to do
2162 if (!StressLdcRewrite && new_index <= max_jubyte) {
2163 // The new value can still use ldc instead of ldc_w
2164 // unless we are trying to stress ldc -> ldc_w rewriting
2165 log_trace(redefine, class, constantpool)
2166 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index);
2167 // We checked that new_index fits in a u1 so this cast is safe
2168 *(bcp + 1) = (u1)new_index;
2169 } else {
2170 log_trace(redefine, class, constantpool)
2171 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index);
2172 // the new value needs ldc_w instead of ldc
2173 u_char inst_buffer[4]; // max instruction size is 4 bytes
2174 bcp = (address)inst_buffer;
2175 // construct new instruction sequence
2176 *bcp = Bytecodes::_ldc_w;
2177 bcp++;
2178 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w.
2179 // See comment below for difference between put_Java_u2()
2180 // and put_native_u2().
2181 Bytes::put_Java_u2(bcp, new_index);
2182
2183 Relocator rc(method, nullptr /* no RelocatorListener needed */);
2184 methodHandle m;
2185 {
2186 PauseNoSafepointVerifier pnsv(&nsv);
2187
2188 // ldc is 2 bytes and ldc_w is 3 bytes
2189 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK);
2190 }
2191
2192 // return the new method so that the caller can update
2193 // the containing class
2194 *new_method_p = method = m;
2195 // switch our bytecode processing loop from the old method
2196 // to the new method
2197 code_base = method->code_base();
2198 code_length = method->code_size();
2199 bcp = code_base + bci;
2200 c = (Bytecodes::Code)(*bcp);
2201 bc_length = Bytecodes::length_for(c);
2202 assert(bc_length != 0, "sanity check");
2203 } // end we need ldc_w instead of ldc
2204 } // end if there is a mapped index
2205 } break;
2206
2207 // these bytecodes have a two-byte constant pool index
2208 case Bytecodes::_anewarray : // fall through
2209 case Bytecodes::_checkcast : // fall through
2210 case Bytecodes::_getfield : // fall through
2211 case Bytecodes::_getstatic : // fall through
2212 case Bytecodes::_instanceof : // fall through
2213 case Bytecodes::_invokedynamic : // fall through
2214 case Bytecodes::_invokeinterface: // fall through
2215 case Bytecodes::_invokespecial : // fall through
2216 case Bytecodes::_invokestatic : // fall through
2217 case Bytecodes::_invokevirtual : // fall through
2218 case Bytecodes::_ldc_w : // fall through
2219 case Bytecodes::_ldc2_w : // fall through
2220 case Bytecodes::_multianewarray : // fall through
2221 case Bytecodes::_new : // fall through
2222 case Bytecodes::_putfield : // fall through
2223 case Bytecodes::_putstatic :
2224 {
2225 address p = bcp + 1;
2226 int cp_index = Bytes::get_Java_u2(p);
2227 u2 new_index = find_new_index(cp_index);
2228 if (new_index != 0) {
2229 // the original index is mapped so update w/ new value
2230 log_trace(redefine, class, constantpool)
2231 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),p2i(bcp), cp_index, new_index);
2232 // Rewriter::rewrite_method() uses put_native_u2() in this
2233 // situation because it is reusing the constant pool index
2234 // location for a native index into the ConstantPoolCache.
2235 // Since we are updating the constant pool index prior to
2236 // verification and ConstantPoolCache initialization, we
2237 // need to keep the new index in Java byte order.
2238 Bytes::put_Java_u2(p, new_index);
2239 }
2240 } break;
2241 default:
2242 break;
2243 }
2244 } // end for each bytecode
2245 } // end rewrite_cp_refs_in_method()
2246
2247
2248 // Rewrite constant pool references in the class_annotations field.
2249 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(InstanceKlass* scratch_class) {
2250
2251 AnnotationArray* class_annotations = scratch_class->class_annotations();
2252 if (class_annotations == nullptr || class_annotations->length() == 0) {
2253 // no class_annotations so nothing to do
2254 return true;
2255 }
2256
2257 log_debug(redefine, class, annotation)("class_annotations length=%d", class_annotations->length());
2258
2259 int byte_i = 0; // byte index into class_annotations
2260 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i);
2261 }
2262
2263
2264 // Rewrite constant pool references in an annotations typeArray. This
2265 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute
2266 // that is described in section 4.8.15 of the 2nd-edition of the VM spec:
2267 //
2268 // annotations_typeArray {
2269 // u2 num_annotations;
2270 // annotation annotations[num_annotations];
2271 // }
2272 //
2273 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray(
2274 AnnotationArray* annotations_typeArray, int &byte_i_ref) {
2275
2276 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2277 // not enough room for num_annotations field
2278 log_debug(redefine, class, annotation)("length() is too small for num_annotations field");
2279 return false;
2280 }
2281
2282 u2 num_annotations = Bytes::get_Java_u2((address)
2283 annotations_typeArray->adr_at(byte_i_ref));
2284 byte_i_ref += 2;
2285
2286 log_debug(redefine, class, annotation)("num_annotations=%d", num_annotations);
2287
2288 int calc_num_annotations = 0;
2289 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
2290 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, byte_i_ref)) {
2291 log_debug(redefine, class, annotation)("bad annotation_struct at %d", calc_num_annotations);
2292 // propagate failure back to caller
2293 return false;
2294 }
2295 }
2296 assert(num_annotations == calc_num_annotations, "sanity check");
2297
2298 return true;
2299 } // end rewrite_cp_refs_in_annotations_typeArray()
2300
2301
2302 // Rewrite constant pool references in the annotation struct portion of
2303 // an annotations_typeArray. This "structure" is from section 4.8.15 of
2304 // the 2nd-edition of the VM spec:
2305 //
2306 // struct annotation {
2307 // u2 type_index;
2308 // u2 num_element_value_pairs;
2309 // {
2310 // u2 element_name_index;
2311 // element_value value;
2312 // } element_value_pairs[num_element_value_pairs];
2313 // }
2314 //
2315 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct(
2316 AnnotationArray* annotations_typeArray, int &byte_i_ref) {
2317 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) {
2318 // not enough room for smallest annotation_struct
2319 log_debug(redefine, class, annotation)("length() is too small for annotation_struct");
2320 return false;
2321 }
2322
2323 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray,
2324 byte_i_ref, "type_index");
2325
2326 u2 num_element_value_pairs = Bytes::get_Java_u2((address)
2327 annotations_typeArray->adr_at(byte_i_ref));
2328 byte_i_ref += 2;
2329
2330 log_debug(redefine, class, annotation)
2331 ("type_index=%d num_element_value_pairs=%d", type_index, num_element_value_pairs);
2332
2333 int calc_num_element_value_pairs = 0;
2334 for (; calc_num_element_value_pairs < num_element_value_pairs;
2335 calc_num_element_value_pairs++) {
2336 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2337 // not enough room for another element_name_index, let alone
2338 // the rest of another component
2339 log_debug(redefine, class, annotation)("length() is too small for element_name_index");
2340 return false;
2341 }
2342
2343 u2 element_name_index = rewrite_cp_ref_in_annotation_data(
2344 annotations_typeArray, byte_i_ref,
2345 "element_name_index");
2346
2347 log_debug(redefine, class, annotation)("element_name_index=%d", element_name_index);
2348
2349 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, byte_i_ref)) {
2350 log_debug(redefine, class, annotation)("bad element_value at %d", calc_num_element_value_pairs);
2351 // propagate failure back to caller
2352 return false;
2353 }
2354 } // end for each component
2355 assert(num_element_value_pairs == calc_num_element_value_pairs,
2356 "sanity check");
2357
2358 return true;
2359 } // end rewrite_cp_refs_in_annotation_struct()
2360
2361
2362 // Rewrite a constant pool reference at the current position in
2363 // annotations_typeArray if needed. Returns the original constant
2364 // pool reference if a rewrite was not needed or the new constant
2365 // pool reference if a rewrite was needed.
2366 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data(
2367 AnnotationArray* annotations_typeArray, int &byte_i_ref,
2368 const char * trace_mesg) {
2369
2370 address cp_index_addr = (address)
2371 annotations_typeArray->adr_at(byte_i_ref);
2372 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr);
2373 u2 new_cp_index = find_new_index(old_cp_index);
2374 if (new_cp_index != 0) {
2375 log_debug(redefine, class, annotation)("mapped old %s=%d", trace_mesg, old_cp_index);
2376 Bytes::put_Java_u2(cp_index_addr, new_cp_index);
2377 old_cp_index = new_cp_index;
2378 }
2379 byte_i_ref += 2;
2380 return old_cp_index;
2381 }
2382
2383
2384 // Rewrite constant pool references in the element_value portion of an
2385 // annotations_typeArray. This "structure" is from section 4.8.15.1 of
2386 // the 2nd-edition of the VM spec:
2387 //
2388 // struct element_value {
2389 // u1 tag;
2390 // union {
2391 // u2 const_value_index;
2392 // {
2393 // u2 type_name_index;
2394 // u2 const_name_index;
2395 // } enum_const_value;
2396 // u2 class_info_index;
2397 // annotation annotation_value;
2398 // struct {
2399 // u2 num_values;
2400 // element_value values[num_values];
2401 // } array_value;
2402 // } value;
2403 // }
2404 //
2405 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value(
2406 AnnotationArray* annotations_typeArray, int &byte_i_ref) {
2407
2408 if ((byte_i_ref + 1) > annotations_typeArray->length()) {
2409 // not enough room for a tag let alone the rest of an element_value
2410 log_debug(redefine, class, annotation)("length() is too small for a tag");
2411 return false;
2412 }
2413
2414 u1 tag = annotations_typeArray->at(byte_i_ref);
2415 byte_i_ref++;
2416 log_debug(redefine, class, annotation)("tag='%c'", tag);
2417
2418 switch (tag) {
2419 // These BaseType tag values are from Table 4.2 in VM spec:
2420 case JVM_SIGNATURE_BYTE:
2421 case JVM_SIGNATURE_CHAR:
2422 case JVM_SIGNATURE_DOUBLE:
2423 case JVM_SIGNATURE_FLOAT:
2424 case JVM_SIGNATURE_INT:
2425 case JVM_SIGNATURE_LONG:
2426 case JVM_SIGNATURE_SHORT:
2427 case JVM_SIGNATURE_BOOLEAN:
2428
2429 // The remaining tag values are from Table 4.8 in the 2nd-edition of
2430 // the VM spec:
2431 case 's':
2432 {
2433 // For the above tag values (including the BaseType values),
2434 // value.const_value_index is right union field.
2435
2436 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2437 // not enough room for a const_value_index
2438 log_debug(redefine, class, annotation)("length() is too small for a const_value_index");
2439 return false;
2440 }
2441
2442 u2 const_value_index = rewrite_cp_ref_in_annotation_data(
2443 annotations_typeArray, byte_i_ref,
2444 "const_value_index");
2445
2446 log_debug(redefine, class, annotation)("const_value_index=%d", const_value_index);
2447 } break;
2448
2449 case 'e':
2450 {
2451 // for the above tag value, value.enum_const_value is right union field
2452
2453 if ((byte_i_ref + 4) > annotations_typeArray->length()) {
2454 // not enough room for a enum_const_value
2455 log_debug(redefine, class, annotation)("length() is too small for a enum_const_value");
2456 return false;
2457 }
2458
2459 u2 type_name_index = rewrite_cp_ref_in_annotation_data(
2460 annotations_typeArray, byte_i_ref,
2461 "type_name_index");
2462
2463 u2 const_name_index = rewrite_cp_ref_in_annotation_data(
2464 annotations_typeArray, byte_i_ref,
2465 "const_name_index");
2466
2467 log_debug(redefine, class, annotation)
2468 ("type_name_index=%d const_name_index=%d", type_name_index, const_name_index);
2469 } break;
2470
2471 case 'c':
2472 {
2473 // for the above tag value, value.class_info_index is right union field
2474
2475 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2476 // not enough room for a class_info_index
2477 log_debug(redefine, class, annotation)("length() is too small for a class_info_index");
2478 return false;
2479 }
2480
2481 u2 class_info_index = rewrite_cp_ref_in_annotation_data(
2482 annotations_typeArray, byte_i_ref,
2483 "class_info_index");
2484
2485 log_debug(redefine, class, annotation)("class_info_index=%d", class_info_index);
2486 } break;
2487
2488 case '@':
2489 // For the above tag value, value.attr_value is the right union
2490 // field. This is a nested annotation.
2491 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, byte_i_ref)) {
2492 // propagate failure back to caller
2493 return false;
2494 }
2495 break;
2496
2497 case JVM_SIGNATURE_ARRAY:
2498 {
2499 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2500 // not enough room for a num_values field
2501 log_debug(redefine, class, annotation)("length() is too small for a num_values field");
2502 return false;
2503 }
2504
2505 // For the above tag value, value.array_value is the right union
2506 // field. This is an array of nested element_value.
2507 u2 num_values = Bytes::get_Java_u2((address)
2508 annotations_typeArray->adr_at(byte_i_ref));
2509 byte_i_ref += 2;
2510 log_debug(redefine, class, annotation)("num_values=%d", num_values);
2511
2512 int calc_num_values = 0;
2513 for (; calc_num_values < num_values; calc_num_values++) {
2514 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, byte_i_ref)) {
2515 log_debug(redefine, class, annotation)("bad nested element_value at %d", calc_num_values);
2516 // propagate failure back to caller
2517 return false;
2518 }
2519 }
2520 assert(num_values == calc_num_values, "sanity check");
2521 } break;
2522
2523 default:
2524 log_debug(redefine, class, annotation)("bad tag=0x%x", tag);
2525 return false;
2526 } // end decode tag field
2527
2528 return true;
2529 } // end rewrite_cp_refs_in_element_value()
2530
2531
2532 // Rewrite constant pool references in a fields_annotations field.
2533 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations(
2534 InstanceKlass* scratch_class) {
2535
2536 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations();
2537
2538 if (fields_annotations == nullptr || fields_annotations->length() == 0) {
2539 // no fields_annotations so nothing to do
2540 return true;
2541 }
2542
2543 log_debug(redefine, class, annotation)("fields_annotations length=%d", fields_annotations->length());
2544
2545 for (int i = 0; i < fields_annotations->length(); i++) {
2546 AnnotationArray* field_annotations = fields_annotations->at(i);
2547 if (field_annotations == nullptr || field_annotations->length() == 0) {
2548 // this field does not have any annotations so skip it
2549 continue;
2550 }
2551
2552 int byte_i = 0; // byte index into field_annotations
2553 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i)) {
2554 log_debug(redefine, class, annotation)("bad field_annotations at %d", i);
2555 // propagate failure back to caller
2556 return false;
2557 }
2558 }
2559
2560 return true;
2561 } // end rewrite_cp_refs_in_fields_annotations()
2562
2563
2564 // Rewrite constant pool references in a methods_annotations field.
2565 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations(
2566 InstanceKlass* scratch_class) {
2567
2568 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2569 Method* m = scratch_class->methods()->at(i);
2570 AnnotationArray* method_annotations = m->constMethod()->method_annotations();
2571
2572 if (method_annotations == nullptr || method_annotations->length() == 0) {
2573 // this method does not have any annotations so skip it
2574 continue;
2575 }
2576
2577 int byte_i = 0; // byte index into method_annotations
2578 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i)) {
2579 log_debug(redefine, class, annotation)("bad method_annotations at %d", i);
2580 // propagate failure back to caller
2581 return false;
2582 }
2583 }
2584
2585 return true;
2586 } // end rewrite_cp_refs_in_methods_annotations()
2587
2588
2589 // Rewrite constant pool references in a methods_parameter_annotations
2590 // field. This "structure" is adapted from the
2591 // RuntimeVisibleParameterAnnotations_attribute described in section
2592 // 4.8.17 of the 2nd-edition of the VM spec:
2593 //
2594 // methods_parameter_annotations_typeArray {
2595 // u1 num_parameters;
2596 // {
2597 // u2 num_annotations;
2598 // annotation annotations[num_annotations];
2599 // } parameter_annotations[num_parameters];
2600 // }
2601 //
2602 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations(
2603 InstanceKlass* scratch_class) {
2604
2605 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2606 Method* m = scratch_class->methods()->at(i);
2607 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations();
2608 if (method_parameter_annotations == nullptr
2609 || method_parameter_annotations->length() == 0) {
2610 // this method does not have any parameter annotations so skip it
2611 continue;
2612 }
2613
2614 if (method_parameter_annotations->length() < 1) {
2615 // not enough room for a num_parameters field
2616 log_debug(redefine, class, annotation)("length() is too small for a num_parameters field at %d", i);
2617 return false;
2618 }
2619
2620 int byte_i = 0; // byte index into method_parameter_annotations
2621
2622 u1 num_parameters = method_parameter_annotations->at(byte_i);
2623 byte_i++;
2624
2625 log_debug(redefine, class, annotation)("num_parameters=%d", num_parameters);
2626
2627 int calc_num_parameters = 0;
2628 for (; calc_num_parameters < num_parameters; calc_num_parameters++) {
2629 if (!rewrite_cp_refs_in_annotations_typeArray(method_parameter_annotations, byte_i)) {
2630 log_debug(redefine, class, annotation)("bad method_parameter_annotations at %d", calc_num_parameters);
2631 // propagate failure back to caller
2632 return false;
2633 }
2634 }
2635 assert(num_parameters == calc_num_parameters, "sanity check");
2636 }
2637
2638 return true;
2639 } // end rewrite_cp_refs_in_methods_parameter_annotations()
2640
2641
2642 // Rewrite constant pool references in a methods_default_annotations
2643 // field. This "structure" is adapted from the AnnotationDefault_attribute
2644 // that is described in section 4.8.19 of the 2nd-edition of the VM spec:
2645 //
2646 // methods_default_annotations_typeArray {
2647 // element_value default_value;
2648 // }
2649 //
2650 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations(
2651 InstanceKlass* scratch_class) {
2652
2653 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2654 Method* m = scratch_class->methods()->at(i);
2655 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations();
2656 if (method_default_annotations == nullptr
2657 || method_default_annotations->length() == 0) {
2658 // this method does not have any default annotations so skip it
2659 continue;
2660 }
2661
2662 int byte_i = 0; // byte index into method_default_annotations
2663
2664 if (!rewrite_cp_refs_in_element_value(
2665 method_default_annotations, byte_i)) {
2666 log_debug(redefine, class, annotation)("bad default element_value at %d", i);
2667 // propagate failure back to caller
2668 return false;
2669 }
2670 }
2671
2672 return true;
2673 } // end rewrite_cp_refs_in_methods_default_annotations()
2674
2675
2676 // Rewrite constant pool references in a class_type_annotations field.
2677 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations(
2678 InstanceKlass* scratch_class) {
2679
2680 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations();
2681 if (class_type_annotations == nullptr || class_type_annotations->length() == 0) {
2682 // no class_type_annotations so nothing to do
2683 return true;
2684 }
2685
2686 log_debug(redefine, class, annotation)("class_type_annotations length=%d", class_type_annotations->length());
2687
2688 int byte_i = 0; // byte index into class_type_annotations
2689 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations,
2690 byte_i, "ClassFile");
2691 } // end rewrite_cp_refs_in_class_type_annotations()
2692
2693
2694 // Rewrite constant pool references in a fields_type_annotations field.
2695 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations(InstanceKlass* scratch_class) {
2696
2697 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations();
2698 if (fields_type_annotations == nullptr || fields_type_annotations->length() == 0) {
2699 // no fields_type_annotations so nothing to do
2700 return true;
2701 }
2702
2703 log_debug(redefine, class, annotation)("fields_type_annotations length=%d", fields_type_annotations->length());
2704
2705 for (int i = 0; i < fields_type_annotations->length(); i++) {
2706 AnnotationArray* field_type_annotations = fields_type_annotations->at(i);
2707 if (field_type_annotations == nullptr || field_type_annotations->length() == 0) {
2708 // this field does not have any annotations so skip it
2709 continue;
2710 }
2711
2712 int byte_i = 0; // byte index into field_type_annotations
2713 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations,
2714 byte_i, "field_info")) {
2715 log_debug(redefine, class, annotation)("bad field_type_annotations at %d", i);
2716 // propagate failure back to caller
2717 return false;
2718 }
2719 }
2720
2721 return true;
2722 } // end rewrite_cp_refs_in_fields_type_annotations()
2723
2724
2725 // Rewrite constant pool references in a methods_type_annotations field.
2726 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations(
2727 InstanceKlass* scratch_class) {
2728
2729 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2730 Method* m = scratch_class->methods()->at(i);
2731 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations();
2732
2733 if (method_type_annotations == nullptr || method_type_annotations->length() == 0) {
2734 // this method does not have any annotations so skip it
2735 continue;
2736 }
2737
2738 log_debug(redefine, class, annotation)("methods type_annotations length=%d", method_type_annotations->length());
2739
2740 int byte_i = 0; // byte index into method_type_annotations
2741 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations,
2742 byte_i, "method_info")) {
2743 log_debug(redefine, class, annotation)("bad method_type_annotations at %d", i);
2744 // propagate failure back to caller
2745 return false;
2746 }
2747 }
2748
2749 return true;
2750 } // end rewrite_cp_refs_in_methods_type_annotations()
2751
2752
2753 // Rewrite constant pool references in a type_annotations
2754 // field. This "structure" is adapted from the
2755 // RuntimeVisibleTypeAnnotations_attribute described in
2756 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2757 //
2758 // type_annotations_typeArray {
2759 // u2 num_annotations;
2760 // type_annotation annotations[num_annotations];
2761 // }
2762 //
2763 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray(
2764 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2765 const char * location_mesg) {
2766
2767 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2768 // not enough room for num_annotations field
2769 log_debug(redefine, class, annotation)("length() is too small for num_annotations field");
2770 return false;
2771 }
2772
2773 u2 num_annotations = Bytes::get_Java_u2((address)
2774 type_annotations_typeArray->adr_at(byte_i_ref));
2775 byte_i_ref += 2;
2776
2777 log_debug(redefine, class, annotation)("num_type_annotations=%d", num_annotations);
2778
2779 int calc_num_annotations = 0;
2780 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
2781 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray,
2782 byte_i_ref, location_mesg)) {
2783 log_debug(redefine, class, annotation)("bad type_annotation_struct at %d", calc_num_annotations);
2784 // propagate failure back to caller
2785 return false;
2786 }
2787 }
2788 assert(num_annotations == calc_num_annotations, "sanity check");
2789
2790 if (byte_i_ref != type_annotations_typeArray->length()) {
2791 log_debug(redefine, class, annotation)
2792 ("read wrong amount of bytes at end of processing type_annotations_typeArray (%d of %d bytes were read)",
2793 byte_i_ref, type_annotations_typeArray->length());
2794 return false;
2795 }
2796
2797 return true;
2798 } // end rewrite_cp_refs_in_type_annotations_typeArray()
2799
2800
2801 // Rewrite constant pool references in a type_annotation
2802 // field. This "structure" is adapted from the
2803 // RuntimeVisibleTypeAnnotations_attribute described in
2804 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2805 //
2806 // type_annotation {
2807 // u1 target_type;
2808 // union {
2809 // type_parameter_target;
2810 // supertype_target;
2811 // type_parameter_bound_target;
2812 // empty_target;
2813 // method_formal_parameter_target;
2814 // throws_target;
2815 // localvar_target;
2816 // catch_target;
2817 // offset_target;
2818 // type_argument_target;
2819 // } target_info;
2820 // type_path target_path;
2821 // annotation anno;
2822 // }
2823 //
2824 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct(
2825 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2826 const char * location_mesg) {
2827
2828 if (!skip_type_annotation_target(type_annotations_typeArray,
2829 byte_i_ref, location_mesg)) {
2830 return false;
2831 }
2832
2833 if (!skip_type_annotation_type_path(type_annotations_typeArray, byte_i_ref)) {
2834 return false;
2835 }
2836
2837 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray, byte_i_ref)) {
2838 return false;
2839 }
2840
2841 return true;
2842 } // end rewrite_cp_refs_in_type_annotation_struct()
2843
2844
2845 // Read, verify and skip over the target_type and target_info part
2846 // so that rewriting can continue in the later parts of the struct.
2847 //
2848 // u1 target_type;
2849 // union {
2850 // type_parameter_target;
2851 // supertype_target;
2852 // type_parameter_bound_target;
2853 // empty_target;
2854 // method_formal_parameter_target;
2855 // throws_target;
2856 // localvar_target;
2857 // catch_target;
2858 // offset_target;
2859 // type_argument_target;
2860 // } target_info;
2861 //
2862 bool VM_RedefineClasses::skip_type_annotation_target(
2863 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2864 const char * location_mesg) {
2865
2866 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2867 // not enough room for a target_type let alone the rest of a type_annotation
2868 log_debug(redefine, class, annotation)("length() is too small for a target_type");
2869 return false;
2870 }
2871
2872 u1 target_type = type_annotations_typeArray->at(byte_i_ref);
2873 byte_i_ref += 1;
2874 log_debug(redefine, class, annotation)("target_type=0x%.2x", target_type);
2875 log_debug(redefine, class, annotation)("location=%s", location_mesg);
2876
2877 // Skip over target_info
2878 switch (target_type) {
2879 case 0x00:
2880 // kind: type parameter declaration of generic class or interface
2881 // location: ClassFile
2882 case 0x01:
2883 // kind: type parameter declaration of generic method or constructor
2884 // location: method_info
2885
2886 {
2887 // struct:
2888 // type_parameter_target {
2889 // u1 type_parameter_index;
2890 // }
2891 //
2892 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2893 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_target");
2894 return false;
2895 }
2896
2897 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2898 byte_i_ref += 1;
2899
2900 log_debug(redefine, class, annotation)("type_parameter_target: type_parameter_index=%d", type_parameter_index);
2901 } break;
2902
2903 case 0x10:
2904 // kind: type in extends clause of class or interface declaration
2905 // or in implements clause of interface declaration
2906 // location: ClassFile
2907
2908 {
2909 // struct:
2910 // supertype_target {
2911 // u2 supertype_index;
2912 // }
2913 //
2914 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2915 log_debug(redefine, class, annotation)("length() is too small for a supertype_target");
2916 return false;
2917 }
2918
2919 u2 supertype_index = Bytes::get_Java_u2((address)
2920 type_annotations_typeArray->adr_at(byte_i_ref));
2921 byte_i_ref += 2;
2922
2923 log_debug(redefine, class, annotation)("supertype_target: supertype_index=%d", supertype_index);
2924 } break;
2925
2926 case 0x11:
2927 // kind: type in bound of type parameter declaration of generic class or interface
2928 // location: ClassFile
2929 case 0x12:
2930 // kind: type in bound of type parameter declaration of generic method or constructor
2931 // location: method_info
2932
2933 {
2934 // struct:
2935 // type_parameter_bound_target {
2936 // u1 type_parameter_index;
2937 // u1 bound_index;
2938 // }
2939 //
2940 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2941 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_bound_target");
2942 return false;
2943 }
2944
2945 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2946 byte_i_ref += 1;
2947 u1 bound_index = type_annotations_typeArray->at(byte_i_ref);
2948 byte_i_ref += 1;
2949
2950 log_debug(redefine, class, annotation)
2951 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d", type_parameter_index, bound_index);
2952 } break;
2953
2954 case 0x13:
2955 // kind: type in field declaration
2956 // location: field_info
2957 case 0x14:
2958 // kind: return type of method, or type of newly constructed object
2959 // location: method_info
2960 case 0x15:
2961 // kind: receiver type of method or constructor
2962 // location: method_info
2963
2964 {
2965 // struct:
2966 // empty_target {
2967 // }
2968 //
2969 log_debug(redefine, class, annotation)("empty_target");
2970 } break;
2971
2972 case 0x16:
2973 // kind: type in formal parameter declaration of method, constructor, or lambda expression
2974 // location: method_info
2975
2976 {
2977 // struct:
2978 // formal_parameter_target {
2979 // u1 formal_parameter_index;
2980 // }
2981 //
2982 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2983 log_debug(redefine, class, annotation)("length() is too small for a formal_parameter_target");
2984 return false;
2985 }
2986
2987 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2988 byte_i_ref += 1;
2989
2990 log_debug(redefine, class, annotation)
2991 ("formal_parameter_target: formal_parameter_index=%d", formal_parameter_index);
2992 } break;
2993
2994 case 0x17:
2995 // kind: type in throws clause of method or constructor
2996 // location: method_info
2997
2998 {
2999 // struct:
3000 // throws_target {
3001 // u2 throws_type_index
3002 // }
3003 //
3004 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
3005 log_debug(redefine, class, annotation)("length() is too small for a throws_target");
3006 return false;
3007 }
3008
3009 u2 throws_type_index = Bytes::get_Java_u2((address)
3010 type_annotations_typeArray->adr_at(byte_i_ref));
3011 byte_i_ref += 2;
3012
3013 log_debug(redefine, class, annotation)("throws_target: throws_type_index=%d", throws_type_index);
3014 } break;
3015
3016 case 0x40:
3017 // kind: type in local variable declaration
3018 // location: Code
3019 case 0x41:
3020 // kind: type in resource variable declaration
3021 // location: Code
3022
3023 {
3024 // struct:
3025 // localvar_target {
3026 // u2 table_length;
3027 // struct {
3028 // u2 start_pc;
3029 // u2 length;
3030 // u2 index;
3031 // } table[table_length];
3032 // }
3033 //
3034 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
3035 // not enough room for a table_length let alone the rest of a localvar_target
3036 log_debug(redefine, class, annotation)("length() is too small for a localvar_target table_length");
3037 return false;
3038 }
3039
3040 u2 table_length = Bytes::get_Java_u2((address)
3041 type_annotations_typeArray->adr_at(byte_i_ref));
3042 byte_i_ref += 2;
3043
3044 log_debug(redefine, class, annotation)("localvar_target: table_length=%d", table_length);
3045
3046 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry
3047 int table_size = table_length * table_struct_size;
3048
3049 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) {
3050 // not enough room for a table
3051 log_debug(redefine, class, annotation)("length() is too small for a table array of length %d", table_length);
3052 return false;
3053 }
3054
3055 // Skip over table
3056 byte_i_ref += table_size;
3057 } break;
3058
3059 case 0x42:
3060 // kind: type in exception parameter declaration
3061 // location: Code
3062
3063 {
3064 // struct:
3065 // catch_target {
3066 // u2 exception_table_index;
3067 // }
3068 //
3069 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
3070 log_debug(redefine, class, annotation)("length() is too small for a catch_target");
3071 return false;
3072 }
3073
3074 u2 exception_table_index = Bytes::get_Java_u2((address)
3075 type_annotations_typeArray->adr_at(byte_i_ref));
3076 byte_i_ref += 2;
3077
3078 log_debug(redefine, class, annotation)("catch_target: exception_table_index=%d", exception_table_index);
3079 } break;
3080
3081 case 0x43:
3082 // kind: type in instanceof expression
3083 // location: Code
3084 case 0x44:
3085 // kind: type in new expression
3086 // location: Code
3087 case 0x45:
3088 // kind: type in method reference expression using ::new
3089 // location: Code
3090 case 0x46:
3091 // kind: type in method reference expression using ::Identifier
3092 // location: Code
3093
3094 {
3095 // struct:
3096 // offset_target {
3097 // u2 offset;
3098 // }
3099 //
3100 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
3101 log_debug(redefine, class, annotation)("length() is too small for a offset_target");
3102 return false;
3103 }
3104
3105 u2 offset = Bytes::get_Java_u2((address)
3106 type_annotations_typeArray->adr_at(byte_i_ref));
3107 byte_i_ref += 2;
3108
3109 log_debug(redefine, class, annotation)("offset_target: offset=%d", offset);
3110 } break;
3111
3112 case 0x47:
3113 // kind: type in cast expression
3114 // location: Code
3115 case 0x48:
3116 // kind: type argument for generic constructor in new expression or
3117 // explicit constructor invocation statement
3118 // location: Code
3119 case 0x49:
3120 // kind: type argument for generic method in method invocation expression
3121 // location: Code
3122 case 0x4A:
3123 // kind: type argument for generic constructor in method reference expression using ::new
3124 // location: Code
3125 case 0x4B:
3126 // kind: type argument for generic method in method reference expression using ::Identifier
3127 // location: Code
3128
3129 {
3130 // struct:
3131 // type_argument_target {
3132 // u2 offset;
3133 // u1 type_argument_index;
3134 // }
3135 //
3136 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) {
3137 log_debug(redefine, class, annotation)("length() is too small for a type_argument_target");
3138 return false;
3139 }
3140
3141 u2 offset = Bytes::get_Java_u2((address)
3142 type_annotations_typeArray->adr_at(byte_i_ref));
3143 byte_i_ref += 2;
3144 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
3145 byte_i_ref += 1;
3146
3147 log_debug(redefine, class, annotation)
3148 ("type_argument_target: offset=%d, type_argument_index=%d", offset, type_argument_index);
3149 } break;
3150
3151 default:
3152 log_debug(redefine, class, annotation)("unknown target_type");
3153 #ifdef ASSERT
3154 ShouldNotReachHere();
3155 #endif
3156 return false;
3157 }
3158
3159 return true;
3160 } // end skip_type_annotation_target()
3161
3162
3163 // Read, verify and skip over the type_path part so that rewriting
3164 // can continue in the later parts of the struct.
3165 //
3166 // type_path {
3167 // u1 path_length;
3168 // {
3169 // u1 type_path_kind;
3170 // u1 type_argument_index;
3171 // } path[path_length];
3172 // }
3173 //
3174 bool VM_RedefineClasses::skip_type_annotation_type_path(
3175 AnnotationArray* type_annotations_typeArray, int &byte_i_ref) {
3176
3177 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
3178 // not enough room for a path_length let alone the rest of the type_path
3179 log_debug(redefine, class, annotation)("length() is too small for a type_path");
3180 return false;
3181 }
3182
3183 u1 path_length = type_annotations_typeArray->at(byte_i_ref);
3184 byte_i_ref += 1;
3185
3186 log_debug(redefine, class, annotation)("type_path: path_length=%d", path_length);
3187
3188 int calc_path_length = 0;
3189 for (; calc_path_length < path_length; calc_path_length++) {
3190 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) {
3191 // not enough room for a path
3192 log_debug(redefine, class, annotation)
3193 ("length() is too small for path entry %d of %d", calc_path_length, path_length);
3194 return false;
3195 }
3196
3197 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref);
3198 byte_i_ref += 1;
3199 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
3200 byte_i_ref += 1;
3201
3202 log_debug(redefine, class, annotation)
3203 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d",
3204 calc_path_length, type_path_kind, type_argument_index);
3205
3206 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) {
3207 // not enough room for a path
3208 log_debug(redefine, class, annotation)("inconsistent type_path values");
3209 return false;
3210 }
3211 }
3212 assert(path_length == calc_path_length, "sanity check");
3213
3214 return true;
3215 } // end skip_type_annotation_type_path()
3216
3217
3218 // Rewrite constant pool references in the method's stackmap table.
3219 // These "structures" are adapted from the StackMapTable_attribute that
3220 // is described in section 4.8.4 of the 6.0 version of the VM spec
3221 // (dated 2005.10.26):
3222 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
3223 //
3224 // stack_map {
3225 // u2 number_of_entries;
3226 // stack_map_frame entries[number_of_entries];
3227 // }
3228 //
3229 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table(
3230 const methodHandle& method) {
3231
3232 if (!method->has_stackmap_table()) {
3233 return;
3234 }
3235
3236 AnnotationArray* stackmap_data = method->stackmap_data();
3237 address stackmap_p = (address)stackmap_data->adr_at(0);
3238 address stackmap_end = stackmap_p + stackmap_data->length();
3239
3240 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries");
3241 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p);
3242 stackmap_p += 2;
3243
3244 log_debug(redefine, class, stackmap)("number_of_entries=%u", number_of_entries);
3245
3246 // walk through each stack_map_frame
3247 u2 calc_number_of_entries = 0;
3248 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) {
3249 // The stack_map_frame structure is a u1 frame_type followed by
3250 // 0 or more bytes of data:
3251 //
3252 // union stack_map_frame {
3253 // same_frame;
3254 // same_locals_1_stack_item_frame;
3255 // same_locals_1_stack_item_frame_extended;
3256 // chop_frame;
3257 // same_frame_extended;
3258 // append_frame;
3259 // full_frame;
3260 // }
3261
3262 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type");
3263 u1 frame_type = *stackmap_p;
3264 stackmap_p++;
3265
3266 // same_frame {
3267 // u1 frame_type = SAME; /* 0-63 */
3268 // }
3269 if (frame_type <= StackMapReader::SAME_FRAME_END) {
3270 // nothing more to do for same_frame
3271 }
3272
3273 // same_locals_1_stack_item_frame {
3274 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */
3275 // verification_type_info stack[1];
3276 // }
3277 else if (frame_type >= StackMapReader::SAME_LOCALS_1_STACK_ITEM_FRAME_START &&
3278 frame_type <= StackMapReader::SAME_LOCALS_1_STACK_ITEM_FRAME_END) {
3279 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3280 calc_number_of_entries, frame_type);
3281 }
3282
3283 // reserved for future use
3284 else if (frame_type >= StackMapReader::RESERVED_START &&
3285 frame_type <= StackMapReader::RESERVED_END) {
3286 // nothing more to do for reserved frame_types
3287 }
3288
3289 // same_locals_1_stack_item_frame_extended {
3290 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */
3291 // u2 offset_delta;
3292 // verification_type_info stack[1];
3293 // }
3294 else if (frame_type == StackMapReader::SAME_LOCALS_1_STACK_ITEM_EXTENDED) {
3295 stackmap_p += 2;
3296 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3297 calc_number_of_entries, frame_type);
3298 }
3299
3300 // chop_frame {
3301 // u1 frame_type = CHOP; /* 248-250 */
3302 // u2 offset_delta;
3303 // }
3304 else if (frame_type >= StackMapReader::CHOP_FRAME_START &&
3305 frame_type <= StackMapReader::CHOP_FRAME_END) {
3306 stackmap_p += 2;
3307 }
3308
3309 // same_frame_extended {
3310 // u1 frame_type = SAME_EXTENDED; /* 251 */
3311 // u2 offset_delta;
3312 // }
3313 else if (frame_type == StackMapReader::SAME_FRAME_EXTENDED) {
3314 stackmap_p += 2;
3315 }
3316
3317 // append_frame {
3318 // u1 frame_type = APPEND; /* 252-254 */
3319 // u2 offset_delta;
3320 // verification_type_info locals[frame_type - SAME_EXTENDED];
3321 // }
3322 else if (frame_type >= StackMapReader::APPEND_FRAME_START &&
3323 frame_type <= StackMapReader::APPEND_FRAME_END) {
3324 assert(stackmap_p + 2 <= stackmap_end,
3325 "no room for offset_delta");
3326 stackmap_p += 2;
3327 u1 len = frame_type - StackMapReader::APPEND_FRAME_START + 1;
3328 for (u1 i = 0; i < len; i++) {
3329 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3330 calc_number_of_entries, frame_type);
3331 }
3332 }
3333
3334 // full_frame {
3335 // u1 frame_type = FULL_FRAME; /* 255 */
3336 // u2 offset_delta;
3337 // u2 number_of_locals;
3338 // verification_type_info locals[number_of_locals];
3339 // u2 number_of_stack_items;
3340 // verification_type_info stack[number_of_stack_items];
3341 // }
3342 else if (frame_type == StackMapReader::FULL_FRAME) {
3343 assert(stackmap_p + 2 + 2 <= stackmap_end,
3344 "no room for smallest full_frame");
3345 stackmap_p += 2;
3346
3347 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p);
3348 stackmap_p += 2;
3349
3350 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) {
3351 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3352 calc_number_of_entries, frame_type);
3353 }
3354
3355 // Use the largest size for the number_of_stack_items, but only get
3356 // the right number of bytes.
3357 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p);
3358 stackmap_p += 2;
3359
3360 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) {
3361 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3362 calc_number_of_entries, frame_type);
3363 }
3364 }
3365 } // end while there is a stack_map_frame
3366 assert(number_of_entries == calc_number_of_entries, "sanity check");
3367 } // end rewrite_cp_refs_in_stack_map_table()
3368
3369
3370 // Rewrite constant pool references in the verification type info
3371 // portion of the method's stackmap table. These "structures" are
3372 // adapted from the StackMapTable_attribute that is described in
3373 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26):
3374 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
3375 //
3376 // The verification_type_info structure is a u1 tag followed by 0 or
3377 // more bytes of data:
3378 //
3379 // union verification_type_info {
3380 // Top_variable_info;
3381 // Integer_variable_info;
3382 // Float_variable_info;
3383 // Long_variable_info;
3384 // Double_variable_info;
3385 // Null_variable_info;
3386 // UninitializedThis_variable_info;
3387 // Object_variable_info;
3388 // Uninitialized_variable_info;
3389 // }
3390 //
3391 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info(
3392 address& stackmap_p_ref, address stackmap_end, u2 frame_i,
3393 u1 frame_type) {
3394
3395 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag");
3396 u1 tag = *stackmap_p_ref;
3397 stackmap_p_ref++;
3398
3399 switch (tag) {
3400 // Top_variable_info {
3401 // u1 tag = ITEM_Top; /* 0 */
3402 // }
3403 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top
3404 case 0: // fall through
3405
3406 // Integer_variable_info {
3407 // u1 tag = ITEM_Integer; /* 1 */
3408 // }
3409 case ITEM_Integer: // fall through
3410
3411 // Float_variable_info {
3412 // u1 tag = ITEM_Float; /* 2 */
3413 // }
3414 case ITEM_Float: // fall through
3415
3416 // Double_variable_info {
3417 // u1 tag = ITEM_Double; /* 3 */
3418 // }
3419 case ITEM_Double: // fall through
3420
3421 // Long_variable_info {
3422 // u1 tag = ITEM_Long; /* 4 */
3423 // }
3424 case ITEM_Long: // fall through
3425
3426 // Null_variable_info {
3427 // u1 tag = ITEM_Null; /* 5 */
3428 // }
3429 case ITEM_Null: // fall through
3430
3431 // UninitializedThis_variable_info {
3432 // u1 tag = ITEM_UninitializedThis; /* 6 */
3433 // }
3434 case ITEM_UninitializedThis:
3435 // nothing more to do for the above tag types
3436 break;
3437
3438 // Object_variable_info {
3439 // u1 tag = ITEM_Object; /* 7 */
3440 // u2 cpool_index;
3441 // }
3442 case ITEM_Object:
3443 {
3444 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index");
3445 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref);
3446 u2 new_cp_index = find_new_index(cpool_index);
3447 if (new_cp_index != 0) {
3448 log_debug(redefine, class, stackmap)("mapped old cpool_index=%d", cpool_index);
3449 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
3450 cpool_index = new_cp_index;
3451 }
3452 stackmap_p_ref += 2;
3453
3454 log_debug(redefine, class, stackmap)
3455 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i, frame_type, cpool_index);
3456 } break;
3457
3458 // Uninitialized_variable_info {
3459 // u1 tag = ITEM_Uninitialized; /* 8 */
3460 // u2 offset;
3461 // }
3462 case ITEM_Uninitialized:
3463 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset");
3464 stackmap_p_ref += 2;
3465 break;
3466
3467 default:
3468 log_debug(redefine, class, stackmap)("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag);
3469 ShouldNotReachHere();
3470 break;
3471 } // end switch (tag)
3472 } // end rewrite_cp_refs_in_verification_type_info()
3473
3474
3475 // Change the constant pool associated with klass scratch_class to scratch_cp.
3476 // scratch_cp_length elements are copied from scratch_cp to a smaller constant pool
3477 // and the smaller constant pool is associated with scratch_class.
3478 void VM_RedefineClasses::set_new_constant_pool(
3479 ClassLoaderData* loader_data,
3480 InstanceKlass* scratch_class, constantPoolHandle scratch_cp,
3481 int scratch_cp_length, TRAPS) {
3482 assert(scratch_cp->length() >= scratch_cp_length, "sanity check");
3483
3484 // scratch_cp is a merged constant pool and has enough space for a
3485 // worst case merge situation. We want to associate the minimum
3486 // sized constant pool with the klass to save space.
3487 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK);
3488 constantPoolHandle smaller_cp(THREAD, cp);
3489
3490 // preserve version() value in the smaller copy
3491 int version = scratch_cp->version();
3492 assert(version != 0, "sanity check");
3493 smaller_cp->set_version(version);
3494
3495 // attach klass to new constant pool
3496 // reference to the cp holder is needed for reallocating the BSM attribute
3497 smaller_cp->set_pool_holder(scratch_class);
3498
3499 smaller_cp->copy_fields(scratch_cp());
3500
3501 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
3502 if (HAS_PENDING_EXCEPTION) {
3503 // Exception is handled in the caller
3504 loader_data->add_to_deallocate_list(smaller_cp());
3505 return;
3506 }
3507 scratch_cp = smaller_cp;
3508
3509 // attach new constant pool to klass
3510 scratch_class->set_constants(scratch_cp());
3511 scratch_cp->initialize_unresolved_klasses(loader_data, CHECK);
3512
3513 int i; // for portability
3514
3515 // update each field in klass to use new constant pool indices as needed
3516 int java_fields;
3517 int injected_fields;
3518 bool update_required = false;
3519 GrowableArray<FieldInfo>* fields = FieldInfoStream::create_FieldInfoArray(scratch_class->fieldinfo_stream(), &java_fields, &injected_fields);
3520 for (int i = 0; i < java_fields; i++) {
3521 FieldInfo* fi = fields->adr_at(i);
3522 jshort cur_index = fi->name_index();
3523 jshort new_index = find_new_index(cur_index);
3524 if (new_index != 0) {
3525 log_trace(redefine, class, constantpool)("field-name_index change: %d to %d", cur_index, new_index);
3526 fi->set_name_index(new_index);
3527 update_required = true;
3528 }
3529 cur_index = fi->signature_index();
3530 new_index = find_new_index(cur_index);
3531 if (new_index != 0) {
3532 log_trace(redefine, class, constantpool)("field-signature_index change: %d to %d", cur_index, new_index);
3533 fi->set_signature_index(new_index);
3534 update_required = true;
3535 }
3536 cur_index = fi->initializer_index();
3537 new_index = find_new_index(cur_index);
3538 if (new_index != 0) {
3539 log_trace(redefine, class, constantpool)("field-initval_index change: %d to %d", cur_index, new_index);
3540 fi->set_initializer_index(new_index);
3541 update_required = true;
3542 }
3543 cur_index = fi->generic_signature_index();
3544 new_index = find_new_index(cur_index);
3545 if (new_index != 0) {
3546 log_trace(redefine, class, constantpool)("field-generic_signature change: %d to %d", cur_index, new_index);
3547 fi->set_generic_signature_index(new_index);
3548 update_required = true;
3549 }
3550 }
3551 if (update_required) {
3552 Array<u1>* old_stream = scratch_class->fieldinfo_stream();
3553 assert(fields->length() == (java_fields + injected_fields), "Must be");
3554 Array<u1>* new_fis = FieldInfoStream::create_FieldInfoStream(fields, java_fields, injected_fields, scratch_class->class_loader_data(), CHECK);
3555 scratch_class->set_fieldinfo_stream(new_fis);
3556 MetadataFactory::free_array<u1>(scratch_class->class_loader_data(), old_stream);
3557
3558 Array<u1>* old_table = scratch_class->fieldinfo_search_table();
3559 Array<u1>* search_table = FieldInfoStream::create_search_table(scratch_class->constants(), new_fis, scratch_class->class_loader_data(), CHECK);
3560 scratch_class->set_fieldinfo_search_table(search_table);
3561 MetadataFactory::free_array<u1>(scratch_class->class_loader_data(), old_table);
3562
3563 DEBUG_ONLY(FieldInfoStream::validate_search_table(scratch_class->constants(), new_fis, search_table));
3564 }
3565
3566 // Update constant pool indices in the inner classes info to use
3567 // new constant indices as needed. The inner classes info is a
3568 // quadruple:
3569 // (inner_class_info, outer_class_info, inner_name, inner_access_flags)
3570 InnerClassesIterator iter(scratch_class);
3571 for (; !iter.done(); iter.next()) {
3572 int cur_index = iter.inner_class_info_index();
3573 if (cur_index == 0) {
3574 continue; // JVM spec. allows null inner class refs so skip it
3575 }
3576 u2 new_index = find_new_index(cur_index);
3577 if (new_index != 0) {
3578 log_trace(redefine, class, constantpool)("inner_class_info change: %d to %d", cur_index, new_index);
3579 iter.set_inner_class_info_index(new_index);
3580 }
3581 cur_index = iter.outer_class_info_index();
3582 new_index = find_new_index(cur_index);
3583 if (new_index != 0) {
3584 log_trace(redefine, class, constantpool)("outer_class_info change: %d to %d", cur_index, new_index);
3585 iter.set_outer_class_info_index(new_index);
3586 }
3587 cur_index = iter.inner_name_index();
3588 new_index = find_new_index(cur_index);
3589 if (new_index != 0) {
3590 log_trace(redefine, class, constantpool)("inner_name change: %d to %d", cur_index, new_index);
3591 iter.set_inner_name_index(new_index);
3592 }
3593 } // end for each inner class
3594
3595 // Attach each method in klass to the new constant pool and update
3596 // to use new constant pool indices as needed:
3597 Array<Method*>* methods = scratch_class->methods();
3598 for (i = methods->length() - 1; i >= 0; i--) {
3599 methodHandle method(THREAD, methods->at(i));
3600 method->set_constants(scratch_cp());
3601
3602 u2 new_index = find_new_index(method->name_index());
3603 if (new_index != 0) {
3604 log_trace(redefine, class, constantpool)
3605 ("method-name_index change: %d to %d", method->name_index(), new_index);
3606 method->set_name_index(new_index);
3607 }
3608 new_index = find_new_index(method->signature_index());
3609 if (new_index != 0) {
3610 log_trace(redefine, class, constantpool)
3611 ("method-signature_index change: %d to %d", method->signature_index(), new_index);
3612 method->set_signature_index(new_index);
3613 }
3614 new_index = find_new_index(method->generic_signature_index());
3615 if (new_index != 0) {
3616 log_trace(redefine, class, constantpool)
3617 ("method-generic_signature_index change: %d to %d", method->generic_signature_index(), new_index);
3618 method->constMethod()->set_generic_signature_index(new_index);
3619 }
3620
3621 // Update constant pool indices in the method's checked exception
3622 // table to use new constant indices as needed.
3623 int cext_length = method->checked_exceptions_length();
3624 if (cext_length > 0) {
3625 CheckedExceptionElement * cext_table =
3626 method->checked_exceptions_start();
3627 for (int j = 0; j < cext_length; j++) {
3628 int cur_index = cext_table[j].class_cp_index;
3629 int new_index = find_new_index(cur_index);
3630 if (new_index != 0) {
3631 log_trace(redefine, class, constantpool)("cext-class_cp_index change: %d to %d", cur_index, new_index);
3632 cext_table[j].class_cp_index = (u2)new_index;
3633 }
3634 } // end for each checked exception table entry
3635 } // end if there are checked exception table entries
3636
3637 // Update each catch type index in the method's exception table
3638 // to use new constant pool indices as needed. The exception table
3639 // holds quadruple entries of the form:
3640 // (beg_bci, end_bci, handler_bci, klass_index)
3641
3642 ExceptionTable ex_table(method());
3643 int ext_length = ex_table.length();
3644
3645 for (int j = 0; j < ext_length; j ++) {
3646 int cur_index = ex_table.catch_type_index(j);
3647 u2 new_index = find_new_index(cur_index);
3648 if (new_index != 0) {
3649 log_trace(redefine, class, constantpool)("ext-klass_index change: %d to %d", cur_index, new_index);
3650 ex_table.set_catch_type_index(j, new_index);
3651 }
3652 } // end for each exception table entry
3653
3654 // Update constant pool indices in the method's local variable
3655 // table to use new constant indices as needed. The local variable
3656 // table hold sextuple entries of the form:
3657 // (start_pc, length, name_index, descriptor_index, signature_index, slot)
3658 int lvt_length = method->localvariable_table_length();
3659 if (lvt_length > 0) {
3660 LocalVariableTableElement * lv_table =
3661 method->localvariable_table_start();
3662 for (int j = 0; j < lvt_length; j++) {
3663 int cur_index = lv_table[j].name_cp_index;
3664 int new_index = find_new_index(cur_index);
3665 if (new_index != 0) {
3666 log_trace(redefine, class, constantpool)("lvt-name_cp_index change: %d to %d", cur_index, new_index);
3667 lv_table[j].name_cp_index = (u2)new_index;
3668 }
3669 cur_index = lv_table[j].descriptor_cp_index;
3670 new_index = find_new_index(cur_index);
3671 if (new_index != 0) {
3672 log_trace(redefine, class, constantpool)("lvt-descriptor_cp_index change: %d to %d", cur_index, new_index);
3673 lv_table[j].descriptor_cp_index = (u2)new_index;
3674 }
3675 cur_index = lv_table[j].signature_cp_index;
3676 new_index = find_new_index(cur_index);
3677 if (new_index != 0) {
3678 log_trace(redefine, class, constantpool)("lvt-signature_cp_index change: %d to %d", cur_index, new_index);
3679 lv_table[j].signature_cp_index = (u2)new_index;
3680 }
3681 } // end for each local variable table entry
3682 } // end if there are local variable table entries
3683
3684 // Update constant pool indices in the method's method_parameters.
3685 int mp_length = method->method_parameters_length();
3686 if (mp_length > 0) {
3687 MethodParametersElement* elem = method->method_parameters_start();
3688 for (int j = 0; j < mp_length; j++) {
3689 const int cp_index = elem[j].name_cp_index;
3690 const int new_cp_index = find_new_index(cp_index);
3691 if (new_cp_index != 0) {
3692 elem[j].name_cp_index = (u2)new_cp_index;
3693 }
3694 }
3695 }
3696
3697 rewrite_cp_refs_in_stack_map_table(method);
3698 } // end for each method
3699 } // end set_new_constant_pool()
3700
3701
3702 // Unevolving classes may point to methods of the_class directly
3703 // from their constant pool caches, itables, and/or vtables. We
3704 // use the ClassLoaderDataGraph::classes_do() facility and this helper
3705 // to fix up these pointers. MethodData also points to old methods and
3706 // must be cleaned.
3707
3708 // Adjust cpools and vtables closure
3709 void VM_RedefineClasses::AdjustAndCleanMetadata::do_klass(Klass* k) {
3710
3711 // This is a very busy routine. We don't want too much tracing
3712 // printed out.
3713 bool trace_name_printed = false;
3714
3715 // If the class being redefined is java.lang.Object, we need to fix all
3716 // array class vtables also. The _has_redefined_Object flag is global.
3717 // Once the java.lang.Object has been redefined (by the current or one
3718 // of the previous VM_RedefineClasses operations) we have to always
3719 // adjust method entries for array classes.
3720 if (k->is_array_klass() && _has_redefined_Object) {
3721 k->vtable().adjust_method_entries(&trace_name_printed);
3722
3723 } else if (k->is_instance_klass()) {
3724 HandleMark hm(_thread);
3725 InstanceKlass *ik = InstanceKlass::cast(k);
3726
3727 // Clean MethodData of this class's methods so they don't refer to
3728 // old methods that are no longer running.
3729 Array<Method*>* methods = ik->methods();
3730 int num_methods = methods->length();
3731 for (int index = 0; index < num_methods; ++index) {
3732 if (methods->at(index)->method_data() != nullptr) {
3733 methods->at(index)->method_data()->clean_weak_method_links();
3734 }
3735 }
3736
3737 // Adjust all vtables, default methods and itables, to clean out old methods.
3738 ResourceMark rm(_thread);
3739 if (ik->vtable_length() > 0) {
3740 ik->vtable().adjust_method_entries(&trace_name_printed);
3741 ik->adjust_default_methods(&trace_name_printed);
3742 }
3743
3744 if (ik->itable_length() > 0) {
3745 ik->itable().adjust_method_entries(&trace_name_printed);
3746 }
3747
3748 // The constant pools in other classes (other_cp) can refer to
3749 // old methods. We have to update method information in
3750 // other_cp's cache. If other_cp has a previous version, then we
3751 // have to repeat the process for each previous version. The
3752 // constant pool cache holds the Method*s for non-virtual
3753 // methods and for virtual, final methods.
3754 //
3755 // Special case: if the current class is being redefined by the current
3756 // VM_RedefineClasses operation, then new_cp has already been attached
3757 // to the_class and old_cp has already been added as a previous version.
3758 // The new_cp doesn't have any cached references to old methods so it
3759 // doesn't need to be updated and we could optimize by skipping it.
3760 // However, the current class can be marked as being redefined by another
3761 // VM_RedefineClasses operation which has already executed its doit_prologue
3762 // and needs cpcache method entries adjusted. For simplicity, the cpcache
3763 // update is done unconditionally. It should result in doing nothing for
3764 // classes being redefined by the current VM_RedefineClasses operation.
3765 // Method entries in the previous version(s) are adjusted as well.
3766 ConstantPoolCache* cp_cache;
3767
3768 // this klass' constant pool cache may need adjustment
3769 ConstantPool* other_cp = ik->constants();
3770 cp_cache = other_cp->cache();
3771 if (cp_cache != nullptr) {
3772 cp_cache->adjust_method_entries(&trace_name_printed);
3773 }
3774
3775 // the previous versions' constant pool caches may need adjustment
3776 for (InstanceKlass* pv_node = ik->previous_versions();
3777 pv_node != nullptr;
3778 pv_node = pv_node->previous_versions()) {
3779 cp_cache = pv_node->constants()->cache();
3780 if (cp_cache != nullptr) {
3781 cp_cache->adjust_method_entries(&trace_name_printed);
3782 }
3783 }
3784 }
3785 }
3786
3787 void VM_RedefineClasses::update_jmethod_ids() {
3788 for (int j = 0; j < _matching_methods_length; ++j) {
3789 Method* old_method = _matching_old_methods[j];
3790 // The method_idnum should be within the range of 1..number-of-methods
3791 // until incremented later for obsolete methods.
3792 // The increment is so if a jmethodID is created for an old obsolete method
3793 // it gets a new jmethodID cache slot in the InstanceKlass.
3794 // They're cleaned out later when all methods of the previous version are purged.
3795 assert(old_method->method_idnum() <= _old_methods->length(),
3796 "shouldn't be incremented yet for obsolete methods");
3797 jmethodID jmid = old_method->find_jmethod_id_or_null();
3798 if (jmid != nullptr) {
3799 // There is a jmethodID, change it to point to the new method
3800 Method* new_method = _matching_new_methods[j];
3801 Method::change_method_associated_with_jmethod_id(jmid, new_method);
3802 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j],
3803 "should be replaced");
3804 }
3805 }
3806 }
3807
3808 int VM_RedefineClasses::check_methods_and_mark_as_obsolete() {
3809 int emcp_method_count = 0;
3810 int obsolete_count = 0;
3811 int old_index = 0;
3812 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
3813 Method* old_method = _matching_old_methods[j];
3814 Method* new_method = _matching_new_methods[j];
3815 Method* old_array_method;
3816
3817 // Maintain an old_index into the _old_methods array by skipping
3818 // deleted methods
3819 while ((old_array_method = _old_methods->at(old_index)) != old_method) {
3820 ++old_index;
3821 }
3822
3823 if (MethodComparator::methods_EMCP(old_method, new_method)) {
3824 // The EMCP definition from JSR-163 requires the bytecodes to be
3825 // the same with the exception of constant pool indices which may
3826 // differ. However, the constants referred to by those indices
3827 // must be the same.
3828 //
3829 // We use methods_EMCP() for comparison since constant pool
3830 // merging can remove duplicate constant pool entries that were
3831 // present in the old method and removed from the rewritten new
3832 // method. A faster binary comparison function would consider the
3833 // old and new methods to be different when they are actually
3834 // EMCP.
3835 //
3836 // The old and new methods are EMCP and you would think that we
3837 // could get rid of one of them here and now and save some space.
3838 // However, the concept of EMCP only considers the bytecodes and
3839 // the constant pool entries in the comparison. Other things,
3840 // e.g., the line number table (LNT) or the local variable table
3841 // (LVT) don't count in the comparison. So the new (and EMCP)
3842 // method can have a new LNT that we need so we can't just
3843 // overwrite the new method with the old method.
3844 //
3845 // When this routine is called, we have already attached the new
3846 // methods to the_class so the old methods are effectively
3847 // overwritten. However, if an old method is still executing,
3848 // then the old method cannot be collected until sometime after
3849 // the old method call has returned. So the overwriting of old
3850 // methods by new methods will save us space except for those
3851 // (hopefully few) old methods that are still executing.
3852 //
3853 // A method refers to a ConstMethod* and this presents another
3854 // possible avenue to space savings. The ConstMethod* in the
3855 // new method contains possibly new attributes (LNT, LVT, etc).
3856 // At first glance, it seems possible to save space by replacing
3857 // the ConstMethod* in the old method with the ConstMethod*
3858 // from the new method. The old and new methods would share the
3859 // same ConstMethod* and we would save the space occupied by
3860 // the old ConstMethod*. However, the ConstMethod* contains
3861 // a back reference to the containing method. Sharing the
3862 // ConstMethod* between two methods could lead to confusion in
3863 // the code that uses the back reference. This would lead to
3864 // brittle code that could be broken in non-obvious ways now or
3865 // in the future.
3866 //
3867 // Another possibility is to copy the ConstMethod* from the new
3868 // method to the old method and then overwrite the new method with
3869 // the old method. Since the ConstMethod* contains the bytecodes
3870 // for the method embedded in the oop, this option would change
3871 // the bytecodes out from under any threads executing the old
3872 // method and make the thread's bcp invalid. Since EMCP requires
3873 // that the bytecodes be the same modulo constant pool indices, it
3874 // is straight forward to compute the correct new bcp in the new
3875 // ConstMethod* from the old bcp in the old ConstMethod*. The
3876 // time consuming part would be searching all the frames in all
3877 // of the threads to find all of the calls to the old method.
3878 //
3879 // It looks like we will have to live with the limited savings
3880 // that we get from effectively overwriting the old methods
3881 // when the new methods are attached to the_class.
3882
3883 // Count number of methods that are EMCP. The method will be marked
3884 // old but not obsolete if it is EMCP.
3885 emcp_method_count++;
3886
3887 // An EMCP method is _not_ obsolete. An obsolete method has a
3888 // different jmethodID than the current method. An EMCP method
3889 // has the same jmethodID as the current method. Having the
3890 // same jmethodID for all EMCP versions of a method allows for
3891 // a consistent view of the EMCP methods regardless of which
3892 // EMCP method you happen to have in hand. For example, a
3893 // breakpoint set in one EMCP method will work for all EMCP
3894 // versions of the method including the current one.
3895 } else {
3896 // mark obsolete methods as such
3897 old_method->set_is_obsolete();
3898 obsolete_count++;
3899
3900 // obsolete methods need a unique idnum so they become new entries in
3901 // the jmethodID cache in InstanceKlass
3902 assert(old_method->method_idnum() == new_method->method_idnum(), "must match");
3903 u2 num = InstanceKlass::cast(_the_class)->next_method_idnum();
3904 if (num != ConstMethod::UNSET_IDNUM) {
3905 old_method->set_method_idnum(num);
3906 }
3907
3908 // With tracing we try not to "yack" too much. The position of
3909 // this trace assumes there are fewer obsolete methods than
3910 // EMCP methods.
3911 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) {
3912 ResourceMark rm;
3913 log_trace(redefine, class, obsolete, mark)
3914 ("mark %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string());
3915 }
3916 }
3917 old_method->set_is_old();
3918 }
3919 for (int i = 0; i < _deleted_methods_length; ++i) {
3920 Method* old_method = _deleted_methods[i];
3921
3922 assert(!old_method->has_vtable_index(),
3923 "cannot delete methods with vtable entries");;
3924
3925 // Mark all deleted methods as old, obsolete and deleted
3926 old_method->set_is_deleted();
3927 old_method->set_is_old();
3928 old_method->set_is_obsolete();
3929 ++obsolete_count;
3930 // With tracing we try not to "yack" too much. The position of
3931 // this trace assumes there are fewer obsolete methods than
3932 // EMCP methods.
3933 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) {
3934 ResourceMark rm;
3935 log_trace(redefine, class, obsolete, mark)
3936 ("mark deleted %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string());
3937 }
3938 }
3939 assert((emcp_method_count + obsolete_count) == _old_methods->length(),
3940 "sanity check");
3941 log_trace(redefine, class, obsolete, mark)("EMCP_cnt=%d, obsolete_cnt=%d", emcp_method_count, obsolete_count);
3942 return emcp_method_count;
3943 }
3944
3945 // This internal class transfers the native function registration from old methods
3946 // to new methods. It is designed to handle both the simple case of unchanged
3947 // native methods and the complex cases of native method prefixes being added and/or
3948 // removed.
3949 // It expects only to be used during the VM_RedefineClasses op (a safepoint).
3950 //
3951 // This class is used after the new methods have been installed in "the_class".
3952 //
3953 // So, for example, the following must be handled. Where 'm' is a method and
3954 // a number followed by an underscore is a prefix.
3955 //
3956 // Old Name New Name
3957 // Simple transfer to new method m -> m
3958 // Add prefix m -> 1_m
3959 // Remove prefix 1_m -> m
3960 // Simultaneous add of prefixes m -> 3_2_1_m
3961 // Simultaneous removal of prefixes 3_2_1_m -> m
3962 // Simultaneous add and remove 1_m -> 2_m
3963 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m
3964 //
3965 class TransferNativeFunctionRegistration {
3966 private:
3967 InstanceKlass* the_class;
3968 int prefix_count;
3969 char** prefixes;
3970
3971 // Recursively search the binary tree of possibly prefixed method names.
3972 // Iteration could be used if all agents were well behaved. Full tree walk is
3973 // more resilent to agents not cleaning up intermediate methods.
3974 // Branch at each depth in the binary tree is:
3975 // (1) without the prefix.
3976 // (2) with the prefix.
3977 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
3978 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len,
3979 Symbol* signature) {
3980 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len);
3981 if (name_symbol != nullptr) {
3982 Method* method = the_class->lookup_method(name_symbol, signature);
3983 if (method != nullptr) {
3984 // Even if prefixed, intermediate methods must exist.
3985 if (method->is_native()) {
3986 // Wahoo, we found a (possibly prefixed) version of the method, return it.
3987 return method;
3988 }
3989 if (depth < prefix_count) {
3990 // Try applying further prefixes (other than this one).
3991 method = search_prefix_name_space(depth+1, name_str, name_len, signature);
3992 if (method != nullptr) {
3993 return method; // found
3994 }
3995
3996 // Try adding this prefix to the method name and see if it matches
3997 // another method name.
3998 char* prefix = prefixes[depth];
3999 size_t prefix_len = strlen(prefix);
4000 size_t trial_len = name_len + prefix_len;
4001 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
4002 strcpy(trial_name_str, prefix);
4003 strcat(trial_name_str, name_str);
4004 method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
4005 signature);
4006 if (method != nullptr) {
4007 // If found along this branch, it was prefixed, mark as such
4008 method->set_is_prefixed_native();
4009 return method; // found
4010 }
4011 }
4012 }
4013 }
4014 return nullptr; // This whole branch bore nothing
4015 }
4016
4017 // Return the method name with old prefixes stripped away.
4018 char* method_name_without_prefixes(Method* method) {
4019 Symbol* name = method->name();
4020 char* name_str = name->as_utf8();
4021
4022 // Old prefixing may be defunct, strip prefixes, if any.
4023 for (int i = prefix_count-1; i >= 0; i--) {
4024 char* prefix = prefixes[i];
4025 size_t prefix_len = strlen(prefix);
4026 if (strncmp(prefix, name_str, prefix_len) == 0) {
4027 name_str += prefix_len;
4028 }
4029 }
4030 return name_str;
4031 }
4032
4033 // Strip any prefixes off the old native method, then try to find a
4034 // (possibly prefixed) new native that matches it.
4035 Method* strip_and_search_for_new_native(Method* method) {
4036 ResourceMark rm;
4037 char* name_str = method_name_without_prefixes(method);
4038 return search_prefix_name_space(0, name_str, strlen(name_str),
4039 method->signature());
4040 }
4041
4042 public:
4043
4044 // Construct a native method transfer processor for this class.
4045 TransferNativeFunctionRegistration(InstanceKlass* _the_class) {
4046 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
4047
4048 the_class = _the_class;
4049 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
4050 }
4051
4052 // Attempt to transfer any of the old or deleted methods that are native
4053 void transfer_registrations(Method** old_methods, int methods_length) {
4054 for (int j = 0; j < methods_length; j++) {
4055 Method* old_method = old_methods[j];
4056
4057 if (old_method->is_native() && old_method->has_native_function()) {
4058 Method* new_method = strip_and_search_for_new_native(old_method);
4059 if (new_method != nullptr) {
4060 // Actually set the native function in the new method.
4061 // Redefine does not send events (except CFLH), certainly not this
4062 // behind the scenes re-registration.
4063 new_method->set_native_function(old_method->native_function(),
4064 !Method::native_bind_event_is_interesting);
4065 }
4066 }
4067 }
4068 }
4069 };
4070
4071 // Don't lose the association between a native method and its JNI function.
4072 void VM_RedefineClasses::transfer_old_native_function_registrations(InstanceKlass* the_class) {
4073 TransferNativeFunctionRegistration transfer(the_class);
4074 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length);
4075 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length);
4076 }
4077
4078 // Deoptimize all compiled code that depends on the classes redefined.
4079 //
4080 // If the can_redefine_classes capability is obtained in the onload
4081 // phase or 'AlwaysRecordEvolDependencies' is true, then the compiler has
4082 // recorded all dependencies from startup. In that case we need only
4083 // deoptimize and throw away all compiled code that depends on the class.
4084 //
4085 // If can_redefine_classes is obtained sometime after the onload phase
4086 // (and 'AlwaysRecordEvolDependencies' is false) then the dependency
4087 // information may be incomplete. In that case the first call to
4088 // RedefineClasses causes all compiled code to be thrown away. As
4089 // can_redefine_classes has been obtained then all future compilations will
4090 // record dependencies so second and subsequent calls to RedefineClasses
4091 // need only throw away code that depends on the class.
4092 //
4093
4094 void VM_RedefineClasses::flush_dependent_code() {
4095 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
4096 assert(JvmtiExport::all_dependencies_are_recorded() || !AlwaysRecordEvolDependencies, "sanity check");
4097
4098 DeoptimizationScope deopt_scope;
4099
4100 // This is the first redefinition, mark all the nmethods for deoptimization
4101 if (!JvmtiExport::all_dependencies_are_recorded()) {
4102 CodeCache::mark_all_nmethods_for_evol_deoptimization(&deopt_scope);
4103 log_debug(redefine, class, nmethod)("Marked all nmethods for deopt");
4104 } else {
4105 CodeCache::mark_dependents_for_evol_deoptimization(&deopt_scope);
4106 log_debug(redefine, class, nmethod)("Marked dependent nmethods for deopt");
4107 }
4108
4109 deopt_scope.deoptimize_marked();
4110
4111 // From now on we know that the dependency information is complete
4112 JvmtiExport::set_all_dependencies_are_recorded(true);
4113 }
4114
4115 void VM_RedefineClasses::compute_added_deleted_matching_methods() {
4116 Method* old_method;
4117 Method* new_method;
4118
4119 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
4120 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
4121 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length());
4122 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
4123
4124 _matching_methods_length = 0;
4125 _deleted_methods_length = 0;
4126 _added_methods_length = 0;
4127
4128 int nj = 0;
4129 int oj = 0;
4130 while (true) {
4131 if (oj >= _old_methods->length()) {
4132 if (nj >= _new_methods->length()) {
4133 break; // we've looked at everything, done
4134 }
4135 // New method at the end
4136 new_method = _new_methods->at(nj);
4137 _added_methods[_added_methods_length++] = new_method;
4138 ++nj;
4139 } else if (nj >= _new_methods->length()) {
4140 // Old method, at the end, is deleted
4141 old_method = _old_methods->at(oj);
4142 _deleted_methods[_deleted_methods_length++] = old_method;
4143 ++oj;
4144 } else {
4145 old_method = _old_methods->at(oj);
4146 new_method = _new_methods->at(nj);
4147 if (old_method->name() == new_method->name()) {
4148 if (old_method->signature() == new_method->signature()) {
4149 _matching_old_methods[_matching_methods_length ] = old_method;
4150 _matching_new_methods[_matching_methods_length++] = new_method;
4151 ++nj;
4152 ++oj;
4153 } else {
4154 // added overloaded have already been moved to the end,
4155 // so this is a deleted overloaded method
4156 _deleted_methods[_deleted_methods_length++] = old_method;
4157 ++oj;
4158 }
4159 } else { // names don't match
4160 if (old_method->name()->fast_compare(new_method->name()) > 0) {
4161 // new method
4162 _added_methods[_added_methods_length++] = new_method;
4163 ++nj;
4164 } else {
4165 // deleted method
4166 _deleted_methods[_deleted_methods_length++] = old_method;
4167 ++oj;
4168 }
4169 }
4170 }
4171 }
4172 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
4173 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
4174 }
4175
4176
4177 void VM_RedefineClasses::swap_annotations(InstanceKlass* the_class,
4178 InstanceKlass* scratch_class) {
4179 // Swap annotation fields values
4180 Annotations* old_annotations = the_class->annotations();
4181 the_class->set_annotations(scratch_class->annotations());
4182 scratch_class->set_annotations(old_annotations);
4183 }
4184
4185
4186 // Install the redefinition of a class:
4187 // - house keeping (flushing breakpoints and caches, deoptimizing
4188 // dependent compiled code)
4189 // - replacing parts in the_class with parts from scratch_class
4190 // - adding a weak reference to track the obsolete but interesting
4191 // parts of the_class
4192 // - adjusting constant pool caches and vtables in other classes
4193 // that refer to methods in the_class. These adjustments use the
4194 // ClassLoaderDataGraph::classes_do() facility which only allows
4195 // a helper method to be specified. The interesting parameters
4196 // that we would like to pass to the helper method are saved in
4197 // static global fields in the VM operation.
4198 void VM_RedefineClasses::redefine_single_class(Thread* current, jclass the_jclass,
4199 InstanceKlass* scratch_class) {
4200
4201 HandleMark hm(current); // make sure handles from this call are freed
4202
4203 if (log_is_enabled(Info, redefine, class, timer)) {
4204 _timer_rsc_phase1.start();
4205 }
4206
4207 InstanceKlass* the_class = get_ik(the_jclass);
4208
4209 // Set a flag to control and optimize adjusting method entries
4210 _has_redefined_Object |= the_class == vmClasses::Object_klass();
4211
4212 // Remove all breakpoints in methods of this class
4213 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
4214 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class);
4215
4216 _old_methods = the_class->methods();
4217 _new_methods = scratch_class->methods();
4218 _the_class = the_class;
4219 compute_added_deleted_matching_methods();
4220 update_jmethod_ids();
4221
4222 _any_class_has_resolved_methods = the_class->has_resolved_methods() || _any_class_has_resolved_methods;
4223
4224 // Attach new constant pool to the original klass. The original
4225 // klass still refers to the old constant pool (for now).
4226 scratch_class->constants()->set_pool_holder(the_class);
4227
4228 #if 0
4229 // In theory, with constant pool merging in place we should be able
4230 // to save space by using the new, merged constant pool in place of
4231 // the old constant pool(s). By "pool(s)" I mean the constant pool in
4232 // the klass version we are replacing now and any constant pool(s) in
4233 // previous versions of klass. Nice theory, doesn't work in practice.
4234 // When this code is enabled, even simple programs throw NullPointer
4235 // exceptions. I'm guessing that this is caused by some constant pool
4236 // cache difference between the new, merged constant pool and the
4237 // constant pool that was just being used by the klass. I'm keeping
4238 // this code around to archive the idea, but the code has to remain
4239 // disabled for now.
4240
4241 // Attach each old method to the new constant pool. This can be
4242 // done here since we are past the bytecode verification and
4243 // constant pool optimization phases.
4244 for (int i = _old_methods->length() - 1; i >= 0; i--) {
4245 Method* method = _old_methods->at(i);
4246 method->set_constants(scratch_class->constants());
4247 }
4248
4249 // NOTE: this doesn't work because you can redefine the same class in two
4250 // threads, each getting their own constant pool data appended to the
4251 // original constant pool. In order for the new methods to work when they
4252 // become old methods, they need to keep their updated copy of the constant pool.
4253
4254 {
4255 // walk all previous versions of the klass
4256 InstanceKlass *ik = the_class;
4257 PreviousVersionWalker pvw(ik);
4258 do {
4259 ik = pvw.next_previous_version();
4260 if (ik != nullptr) {
4261
4262 // attach previous version of klass to the new constant pool
4263 ik->set_constants(scratch_class->constants());
4264
4265 // Attach each method in the previous version of klass to the
4266 // new constant pool
4267 Array<Method*>* prev_methods = ik->methods();
4268 for (int i = prev_methods->length() - 1; i >= 0; i--) {
4269 Method* method = prev_methods->at(i);
4270 method->set_constants(scratch_class->constants());
4271 }
4272 }
4273 } while (ik != nullptr);
4274 }
4275 #endif
4276
4277 // Replace methods and constantpool
4278 the_class->set_methods(_new_methods);
4279 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods,
4280 // and to be able to undo operation easily.
4281
4282 Array<int>* old_ordering = the_class->method_ordering();
4283 the_class->set_method_ordering(scratch_class->method_ordering());
4284 scratch_class->set_method_ordering(old_ordering);
4285
4286 ConstantPool* old_constants = the_class->constants();
4287 the_class->set_constants(scratch_class->constants());
4288 scratch_class->set_constants(old_constants); // See the previous comment.
4289 #if 0
4290 // We are swapping the guts of "the new class" with the guts of "the
4291 // class". Since the old constant pool has just been attached to "the
4292 // new class", it seems logical to set the pool holder in the old
4293 // constant pool also. However, doing this will change the observable
4294 // class hierarchy for any old methods that are still executing. A
4295 // method can query the identity of its "holder" and this query uses
4296 // the method's constant pool link to find the holder. The change in
4297 // holding class from "the class" to "the new class" can confuse
4298 // things.
4299 //
4300 // Setting the old constant pool's holder will also cause
4301 // verification done during vtable initialization below to fail.
4302 // During vtable initialization, the vtable's class is verified to be
4303 // a subtype of the method's holder. The vtable's class is "the
4304 // class" and the method's holder is gotten from the constant pool
4305 // link in the method itself. For "the class"'s directly implemented
4306 // methods, the method holder is "the class" itself (as gotten from
4307 // the new constant pool). The check works fine in this case. The
4308 // check also works fine for methods inherited from super classes.
4309 //
4310 // Miranda methods are a little more complicated. A miranda method is
4311 // provided by an interface when the class implementing the interface
4312 // does not provide its own method. These interfaces are implemented
4313 // internally as an InstanceKlass. These special instanceKlasses
4314 // share the constant pool of the class that "implements" the
4315 // interface. By sharing the constant pool, the method holder of a
4316 // miranda method is the class that "implements" the interface. In a
4317 // non-redefine situation, the subtype check works fine. However, if
4318 // the old constant pool's pool holder is modified, then the check
4319 // fails because there is no class hierarchy relationship between the
4320 // vtable's class and "the new class".
4321
4322 old_constants->set_pool_holder(scratch_class());
4323 #endif
4324
4325 // track number of methods that are EMCP for add_previous_version() call below
4326 int emcp_method_count = check_methods_and_mark_as_obsolete();
4327 transfer_old_native_function_registrations(the_class);
4328
4329 if (scratch_class->get_cached_class_file() != the_class->get_cached_class_file()) {
4330 // 1. the_class doesn't have a cache yet, scratch_class does have a cache.
4331 // 2. The same class can be present twice in the scratch classes list or there
4332 // are multiple concurrent RetransformClasses calls on different threads.
4333 // the_class and scratch_class have the same cached bytes, but different buffers.
4334 // In such cases we need to deallocate one of the buffers.
4335 // 3. RedefineClasses and the_class has cached bytes from a previous transformation.
4336 // In the case we need to use class bytes from scratch_class.
4337 if (the_class->get_cached_class_file() != nullptr) {
4338 os::free(the_class->get_cached_class_file());
4339 }
4340 the_class->set_cached_class_file(scratch_class->get_cached_class_file());
4341 }
4342
4343 // null out in scratch class to not delete twice. The class to be redefined
4344 // always owns these bytes.
4345 scratch_class->set_cached_class_file(nullptr);
4346
4347 // Replace inner_classes
4348 Array<u2>* old_inner_classes = the_class->inner_classes();
4349 the_class->set_inner_classes(scratch_class->inner_classes());
4350 scratch_class->set_inner_classes(old_inner_classes);
4351
4352 // Initialize the vtable and interface table after
4353 // methods have been rewritten
4354 // no exception should happen here since we explicitly
4355 // do not check loader constraints.
4356 // compare_and_normalize_class_versions has already checked:
4357 // - classloaders unchanged, signatures unchanged
4358 // - all instanceKlasses for redefined classes reused & contents updated
4359 the_class->vtable().initialize_vtable();
4360 the_class->itable().initialize_itable();
4361
4362 // Update jmethodID cache if present.
4363 the_class->update_methods_jmethod_cache();
4364
4365 // Copy the "source debug extension" attribute from new class version
4366 the_class->set_source_debug_extension(
4367 scratch_class->source_debug_extension(),
4368 scratch_class->source_debug_extension() == nullptr ? 0 :
4369 (int)strlen(scratch_class->source_debug_extension()));
4370
4371 // Use of javac -g could be different in the old and the new
4372 if (scratch_class->has_localvariable_table() !=
4373 the_class->has_localvariable_table()) {
4374 the_class->set_has_localvariable_table(scratch_class->has_localvariable_table());
4375 }
4376
4377 swap_annotations(the_class, scratch_class);
4378
4379 // Replace minor version number of class file
4380 u2 old_minor_version = the_class->constants()->minor_version();
4381 the_class->constants()->set_minor_version(scratch_class->constants()->minor_version());
4382 scratch_class->constants()->set_minor_version(old_minor_version);
4383
4384 // Replace major version number of class file
4385 u2 old_major_version = the_class->constants()->major_version();
4386 the_class->constants()->set_major_version(scratch_class->constants()->major_version());
4387 scratch_class->constants()->set_major_version(old_major_version);
4388
4389 // Replace CP indexes for class and name+type of enclosing method
4390 u2 old_class_idx = the_class->enclosing_method_class_index();
4391 u2 old_method_idx = the_class->enclosing_method_method_index();
4392 the_class->set_enclosing_method_indices(
4393 scratch_class->enclosing_method_class_index(),
4394 scratch_class->enclosing_method_method_index());
4395 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx);
4396
4397 if (!the_class->has_been_redefined()) {
4398 the_class->set_has_been_redefined();
4399 }
4400
4401 // Scratch class is unloaded but still needs cleaning, and skipping for CDS.
4402 scratch_class->set_is_scratch_class();
4403
4404 // keep track of previous versions of this class
4405 the_class->add_previous_version(scratch_class, emcp_method_count);
4406
4407 JFR_ONLY(Jfr::on_klass_redefinition(the_class, scratch_class);)
4408
4409 _timer_rsc_phase1.stop();
4410 if (log_is_enabled(Info, redefine, class, timer)) {
4411 _timer_rsc_phase2.start();
4412 }
4413
4414 if (the_class->oop_map_cache() != nullptr) {
4415 // Flush references to any obsolete methods from the oop map cache
4416 // so that obsolete methods are not pinned.
4417 the_class->oop_map_cache()->flush_obsolete_entries();
4418 }
4419
4420 increment_class_counter(the_class);
4421
4422 if (EventClassRedefinition::is_enabled()) {
4423 EventClassRedefinition event;
4424 event.set_classModificationCount(java_lang_Class::classRedefinedCount(the_class->java_mirror()));
4425 event.set_redefinedClass(the_class);
4426 event.set_redefinitionId(_id);
4427 event.commit();
4428 }
4429
4430 {
4431 ResourceMark rm(current);
4432 // increment the classRedefinedCount field in the_class and in any
4433 // direct and indirect subclasses of the_class
4434 physical_memory_size_type avail_mem = 0;
4435 // Return value ignored - defaulting to 0 on failure.
4436 (void)os::available_memory(avail_mem);
4437 log_info(redefine, class, load)
4438 ("redefined name=%s, count=%d (avail_mem=" PHYS_MEM_TYPE_FORMAT "K)",
4439 the_class->external_name(), java_lang_Class::classRedefinedCount(the_class->java_mirror()), avail_mem >> 10);
4440 Events::log_redefinition(current, "redefined class name=%s, count=%d",
4441 the_class->external_name(),
4442 java_lang_Class::classRedefinedCount(the_class->java_mirror()));
4443
4444 }
4445 _timer_rsc_phase2.stop();
4446
4447 } // end redefine_single_class()
4448
4449
4450 // Increment the classRedefinedCount field in the specific InstanceKlass
4451 // and in all direct and indirect subclasses.
4452 void VM_RedefineClasses::increment_class_counter(InstanceKlass* ik) {
4453 for (ClassHierarchyIterator iter(ik); !iter.done(); iter.next()) {
4454 // Only update instanceKlasses
4455 Klass* sub = iter.klass();
4456 if (sub->is_instance_klass()) {
4457 oop class_mirror = InstanceKlass::cast(sub)->java_mirror();
4458 Klass* class_oop = java_lang_Class::as_Klass(class_mirror);
4459 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
4460 java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
4461
4462 if (class_oop != _the_class) {
4463 // _the_class count is printed at end of redefine_single_class()
4464 log_debug(redefine, class, subclass)("updated count in subclass=%s to %d", ik->external_name(), new_count);
4465 }
4466 }
4467 }
4468 }
4469
4470 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) {
4471 bool no_old_methods = true; // be optimistic
4472
4473 // Both array and instance classes have vtables.
4474 // a vtable should never contain old or obsolete methods
4475 ResourceMark rm(_thread);
4476 if (k->vtable_length() > 0 &&
4477 !k->vtable().check_no_old_or_obsolete_entries()) {
4478 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4479 log_trace(redefine, class, obsolete, metadata)
4480 ("klassVtable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4481 k->signature_name());
4482 k->vtable().dump_vtable();
4483 }
4484 no_old_methods = false;
4485 }
4486
4487 if (k->is_instance_klass()) {
4488 HandleMark hm(_thread);
4489 InstanceKlass *ik = InstanceKlass::cast(k);
4490
4491 // an itable should never contain old or obsolete methods
4492 if (ik->itable_length() > 0 &&
4493 !ik->itable().check_no_old_or_obsolete_entries()) {
4494 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4495 log_trace(redefine, class, obsolete, metadata)
4496 ("klassItable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4497 ik->signature_name());
4498 ik->itable().dump_itable();
4499 }
4500 no_old_methods = false;
4501 }
4502
4503 // the constant pool cache should never contain non-deleted old or obsolete methods
4504 if (ik->constants() != nullptr &&
4505 ik->constants()->cache() != nullptr &&
4506 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) {
4507 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4508 log_trace(redefine, class, obsolete, metadata)
4509 ("cp-cache::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4510 ik->signature_name());
4511 ik->constants()->cache()->dump_cache();
4512 }
4513 no_old_methods = false;
4514 }
4515 }
4516
4517 // print and fail guarantee if old methods are found.
4518 if (!no_old_methods) {
4519 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4520 dump_methods();
4521 } else {
4522 log_trace(redefine, class)("Use the '-Xlog:redefine+class*:' option "
4523 "to see more info about the following guarantee() failure.");
4524 }
4525 guarantee(false, "OLD and/or OBSOLETE method(s) found");
4526 }
4527 }
4528
4529 u8 VM_RedefineClasses::next_id() {
4530 while (true) {
4531 u8 id = _id_counter;
4532 u8 next_id = id + 1;
4533 u8 result = AtomicAccess::cmpxchg(&_id_counter, id, next_id);
4534 if (result == id) {
4535 return next_id;
4536 }
4537 }
4538 }
4539
4540 void VM_RedefineClasses::dump_methods() {
4541 int j;
4542 log_trace(redefine, class, dump)("_old_methods --");
4543 for (j = 0; j < _old_methods->length(); ++j) {
4544 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4545 Method* m = _old_methods->at(j);
4546 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4547 m->access_flags().print_on(&log_stream);
4548 log_stream.print(" -- ");
4549 m->print_name(&log_stream);
4550 log_stream.cr();
4551 }
4552 log_trace(redefine, class, dump)("_new_methods --");
4553 for (j = 0; j < _new_methods->length(); ++j) {
4554 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4555 Method* m = _new_methods->at(j);
4556 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4557 m->access_flags().print_on(&log_stream);
4558 log_stream.print(" -- ");
4559 m->print_name(&log_stream);
4560 log_stream.cr();
4561 }
4562 log_trace(redefine, class, dump)("_matching_methods --");
4563 for (j = 0; j < _matching_methods_length; ++j) {
4564 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4565 Method* m = _matching_old_methods[j];
4566 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4567 m->access_flags().print_on(&log_stream);
4568 log_stream.print(" -- ");
4569 m->print_name();
4570 log_stream.cr();
4571
4572 m = _matching_new_methods[j];
4573 log_stream.print(" (%5d) ", m->vtable_index());
4574 m->access_flags().print_on(&log_stream);
4575 log_stream.cr();
4576 }
4577 log_trace(redefine, class, dump)("_deleted_methods --");
4578 for (j = 0; j < _deleted_methods_length; ++j) {
4579 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4580 Method* m = _deleted_methods[j];
4581 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4582 m->access_flags().print_on(&log_stream);
4583 log_stream.print(" -- ");
4584 m->print_name(&log_stream);
4585 log_stream.cr();
4586 }
4587 log_trace(redefine, class, dump)("_added_methods --");
4588 for (j = 0; j < _added_methods_length; ++j) {
4589 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4590 Method* m = _added_methods[j];
4591 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4592 m->access_flags().print_on(&log_stream);
4593 log_stream.print(" -- ");
4594 m->print_name(&log_stream);
4595 log_stream.cr();
4596 }
4597 }
4598
4599 void VM_RedefineClasses::print_on_error(outputStream* st) const {
4600 VM_Operation::print_on_error(st);
4601 if (_the_class != nullptr) {
4602 ResourceMark rm;
4603 st->print_cr(", redefining class %s", _the_class->external_name());
4604 }
4605 }