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/cdsConfig.hpp"
26 #include "cds/metaspaceShared.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/constantPool.hpp"
49 #include "oops/fieldStreams.inline.hpp"
50 #include "oops/klass.inline.hpp"
51 #include "oops/klassVtable.hpp"
52 #include "oops/method.hpp"
53 #include "oops/oop.inline.hpp"
54 #include "oops/recordComponent.hpp"
55 #include "prims/jvmtiImpl.hpp"
56 #include "prims/jvmtiRedefineClasses.hpp"
57 #include "prims/jvmtiThreadState.inline.hpp"
58 #include "prims/methodComparator.hpp"
59 #include "prims/resolvedMethodTable.hpp"
60 #include "runtime/atomic.hpp"
61 #include "runtime/deoptimization.hpp"
62 #include "runtime/handles.inline.hpp"
63 #include "runtime/jniHandles.inline.hpp"
64 #include "runtime/relocator.hpp"
65 #include "runtime/safepointVerifiers.hpp"
66 #include "utilities/bitMap.inline.hpp"
67 #include "utilities/checkedCast.hpp"
68 #include "utilities/events.hpp"
69 #include "utilities/macros.hpp"
70 #if INCLUDE_JFR
71 #include "jfr/jfr.hpp"
72 #endif
73
74 Array<Method*>* VM_RedefineClasses::_old_methods = nullptr;
75 Array<Method*>* VM_RedefineClasses::_new_methods = nullptr;
76 Method** VM_RedefineClasses::_matching_old_methods = nullptr;
77 Method** VM_RedefineClasses::_matching_new_methods = nullptr;
78 Method** VM_RedefineClasses::_deleted_methods = nullptr;
79 Method** VM_RedefineClasses::_added_methods = nullptr;
80 int VM_RedefineClasses::_matching_methods_length = 0;
81 int VM_RedefineClasses::_deleted_methods_length = 0;
82 int VM_RedefineClasses::_added_methods_length = 0;
83
84 // This flag is global as the constructor does not reset it:
85 bool VM_RedefineClasses::_has_redefined_Object = false;
86 u8 VM_RedefineClasses::_id_counter = 0;
87
88 VM_RedefineClasses::VM_RedefineClasses(jint class_count,
89 const jvmtiClassDefinition *class_defs,
90 JvmtiClassLoadKind class_load_kind) {
91 _class_count = class_count;
92 _class_defs = class_defs;
93 _class_load_kind = class_load_kind;
94 _any_class_has_resolved_methods = false;
95 _res = JVMTI_ERROR_NONE;
96 _the_class = nullptr;
97 _id = next_id();
98 }
99
100 static inline InstanceKlass* get_ik(jclass def) {
101 oop mirror = JNIHandles::resolve_non_null(def);
102 return InstanceKlass::cast(java_lang_Class::as_Klass(mirror));
103 }
104
105 // If any of the classes are being redefined, wait
106 // Parallel constant pool merging leads to indeterminate constant pools.
107 void VM_RedefineClasses::lock_classes() {
108 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
109 GrowableArray<Klass*>* redef_classes = state->get_classes_being_redefined();
110
111 MonitorLocker ml(RedefineClasses_lock);
112
113 if (redef_classes == nullptr) {
114 redef_classes = new (mtClass) GrowableArray<Klass*>(1, mtClass);
115 state->set_classes_being_redefined(redef_classes);
116 }
117
118 bool has_redefined;
119 do {
120 has_redefined = false;
121 // Go through classes each time until none are being redefined. Skip
122 // the ones that are being redefined by this thread currently. Class file
123 // load hook event may trigger new class redefine when we are redefining
124 // a class (after lock_classes()).
125 for (int i = 0; i < _class_count; i++) {
126 InstanceKlass* ik = get_ik(_class_defs[i].klass);
127 // Check if we are currently redefining the class in this thread already.
128 if (redef_classes->contains(ik)) {
129 assert(ik->is_being_redefined(), "sanity");
130 } else {
131 if (ik->is_being_redefined()) {
132 ml.wait();
133 has_redefined = true;
134 break; // for loop
135 }
136 }
137 }
138 } while (has_redefined);
139
140 for (int i = 0; i < _class_count; i++) {
141 InstanceKlass* ik = get_ik(_class_defs[i].klass);
142 redef_classes->push(ik); // Add to the _classes_being_redefined list
143 ik->set_is_being_redefined(true);
144 }
145 ml.notify_all();
146 }
147
148 void VM_RedefineClasses::unlock_classes() {
149 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
150 GrowableArray<Klass*>* redef_classes = state->get_classes_being_redefined();
151 assert(redef_classes != nullptr, "_classes_being_redefined is not allocated");
152
153 MonitorLocker ml(RedefineClasses_lock);
154
155 for (int i = _class_count - 1; i >= 0; i--) {
156 InstanceKlass* def_ik = get_ik(_class_defs[i].klass);
157 if (redef_classes->length() > 0) {
158 // Remove the class from _classes_being_redefined list
159 Klass* k = redef_classes->pop();
160 assert(def_ik == k, "unlocking wrong class");
161 }
162 assert(def_ik->is_being_redefined(),
163 "should be being redefined to get here");
164
165 // Unlock after we finish all redefines for this class within
166 // the thread. Same class can be pushed to the list multiple
167 // times (not more than once by each recursive redefinition).
168 if (!redef_classes->contains(def_ik)) {
169 def_ik->set_is_being_redefined(false);
170 }
171 }
172 ml.notify_all();
173 }
174
175 bool VM_RedefineClasses::doit_prologue() {
176 if (_class_count == 0) {
177 _res = JVMTI_ERROR_NONE;
178 return false;
179 }
180 if (_class_defs == nullptr) {
181 _res = JVMTI_ERROR_NULL_POINTER;
182 return false;
183 }
184
185 for (int i = 0; i < _class_count; i++) {
186 if (_class_defs[i].klass == nullptr) {
187 _res = JVMTI_ERROR_INVALID_CLASS;
188 return false;
189 }
190 if (_class_defs[i].class_byte_count == 0) {
191 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT;
192 return false;
193 }
194 if (_class_defs[i].class_bytes == nullptr) {
195 _res = JVMTI_ERROR_NULL_POINTER;
196 return false;
197 }
198
199 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass);
200 // classes for primitives, arrays, and hidden classes
201 // cannot be redefined.
202 if (!is_modifiable_class(mirror)) {
203 _res = JVMTI_ERROR_UNMODIFIABLE_CLASS;
204 return false;
205 }
206 }
207
208 // Start timer after all the sanity checks; not quite accurate, but
209 // better than adding a bunch of stop() calls.
210 if (log_is_enabled(Info, redefine, class, timer)) {
211 _timer_vm_op_prologue.start();
212 }
213
214 lock_classes();
215 // We first load new class versions in the prologue, because somewhere down the
216 // call chain it is required that the current thread is a Java thread.
217 _res = load_new_class_versions();
218 if (_res != JVMTI_ERROR_NONE) {
219 // free any successfully created classes, since none are redefined
220 for (int i = 0; i < _class_count; i++) {
221 if (_scratch_classes[i] != nullptr) {
222 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data();
223 // Free the memory for this class at class unloading time. Not before
224 // because CMS might think this is still live.
225 InstanceKlass* ik = get_ik(_class_defs[i].klass);
226 if (ik->get_cached_class_file() == _scratch_classes[i]->get_cached_class_file()) {
227 // Don't double-free cached_class_file copied from the original class if error.
228 _scratch_classes[i]->set_cached_class_file(nullptr);
229 }
230 cld->add_to_deallocate_list(InstanceKlass::cast(_scratch_classes[i]));
231 }
232 }
233 // Free os::malloc allocated memory in load_new_class_version.
234 os::free(_scratch_classes);
235 _timer_vm_op_prologue.stop();
236 unlock_classes();
237 return false;
238 }
239
240 _timer_vm_op_prologue.stop();
241 return true;
242 }
243
244 void VM_RedefineClasses::doit() {
245 Thread* current = Thread::current();
246
247 if (log_is_enabled(Info, redefine, class, timer)) {
248 _timer_vm_op_doit.start();
249 }
250
251 #if INCLUDE_CDS
252 if (CDSConfig::is_using_archive()) {
253 // Sharing is enabled so we remap the shared readonly space to
254 // shared readwrite, private just in case we need to redefine
255 // a shared class. We do the remap during the doit() phase of
256 // the safepoint to be safer.
257 if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) {
258 log_info(redefine, class, load)("failed to remap shared readonly space to readwrite, private");
259 _res = JVMTI_ERROR_INTERNAL;
260 _timer_vm_op_doit.stop();
261 return;
262 }
263 }
264 #endif
265
266 // Mark methods seen on stack and everywhere else so old methods are not
267 // cleaned up if they're on the stack.
268 MetadataOnStackMark md_on_stack(/*walk_all_metadata*/true, /*redefinition_walk*/true);
269 HandleMark hm(current); // make sure any handles created are deleted
270 // before the stack walk again.
271
272 for (int i = 0; i < _class_count; i++) {
273 redefine_single_class(current, _class_defs[i].klass, _scratch_classes[i]);
274 }
275
276 // Flush all compiled code that depends on the classes redefined.
277 flush_dependent_code();
278
279 // Adjust constantpool caches and vtables for all classes
280 // that reference methods of the evolved classes.
281 // Have to do this after all classes are redefined and all methods that
282 // are redefined are marked as old.
283 AdjustAndCleanMetadata adjust_and_clean_metadata(current);
284 ClassLoaderDataGraph::classes_do(&adjust_and_clean_metadata);
285
286 // JSR-292 support
287 if (_any_class_has_resolved_methods) {
288 bool trace_name_printed = false;
289 ResolvedMethodTable::adjust_method_entries(&trace_name_printed);
290 }
291
292 // Increment flag indicating that some invariants are no longer true.
293 // See jvmtiExport.hpp for detailed explanation.
294 JvmtiExport::increment_redefinition_count();
295
296 // check_class() is optionally called for product bits, but is
297 // always called for non-product bits.
298 #ifdef PRODUCT
299 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
300 #endif
301 log_trace(redefine, class, obsolete, metadata)("calling check_class");
302 CheckClass check_class(current);
303 ClassLoaderDataGraph::classes_do(&check_class);
304 #ifdef PRODUCT
305 }
306 #endif
307
308 // Clean up any metadata now unreferenced while MetadataOnStackMark is set.
309 ClassLoaderDataGraph::clean_deallocate_lists(false);
310
311 _timer_vm_op_doit.stop();
312 }
313
314 void VM_RedefineClasses::doit_epilogue() {
315 unlock_classes();
316
317 // Free os::malloc allocated memory.
318 os::free(_scratch_classes);
319
320 // Reset the_class to null for error printing.
321 _the_class = nullptr;
322
323 if (log_is_enabled(Info, redefine, class, timer)) {
324 // Used to have separate timers for "doit" and "all", but the timer
325 // overhead skewed the measurements.
326 julong doit_time = _timer_vm_op_doit.milliseconds();
327 julong all_time = _timer_vm_op_prologue.milliseconds() + doit_time;
328
329 log_info(redefine, class, timer)
330 ("vm_op: all=" JULONG_FORMAT " prologue=" JULONG_FORMAT " doit=" JULONG_FORMAT,
331 all_time, (julong)_timer_vm_op_prologue.milliseconds(), doit_time);
332 log_info(redefine, class, timer)
333 ("redefine_single_class: phase1=" JULONG_FORMAT " phase2=" JULONG_FORMAT,
334 (julong)_timer_rsc_phase1.milliseconds(), (julong)_timer_rsc_phase2.milliseconds());
335 }
336 }
337
338 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) {
339 // classes for primitives cannot be redefined
340 if (java_lang_Class::is_primitive(klass_mirror)) {
341 return false;
342 }
343 Klass* k = java_lang_Class::as_Klass(klass_mirror);
344 // classes for arrays cannot be redefined
345 if (k == nullptr || !k->is_instance_klass()) {
346 return false;
347 }
348
349 // Cannot redefine or retransform a hidden class.
350 if (InstanceKlass::cast(k)->is_hidden()) {
351 return false;
352 }
353 if (InstanceKlass::cast(k) == vmClasses::Continuation_klass()) {
354 // Don't redefine Continuation class. See 8302779.
355 return false;
356 }
357 return true;
358 }
359
360 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p
361 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For
362 // direct CP entries, there is just the current entry to append. For
363 // indirect and double-indirect CP entries, there are zero or more
364 // referenced CP entries along with the current entry to append.
365 // Indirect and double-indirect CP entries are handled by recursive
366 // calls to append_entry() as needed. The referenced CP entries are
367 // always appended to *merge_cp_p before the referee CP entry. These
368 // referenced CP entries may already exist in *merge_cp_p in which case
369 // there is nothing extra to append and only the current entry is
370 // appended.
371 void VM_RedefineClasses::append_entry(const constantPoolHandle& scratch_cp,
372 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) {
373
374 // append is different depending on entry tag type
375 switch (scratch_cp->tag_at(scratch_i).value()) {
376
377 // The old verifier is implemented outside the VM. It loads classes,
378 // but does not resolve constant pool entries directly so we never
379 // see Class entries here with the old verifier. Similarly the old
380 // verifier does not like Class entries in the input constant pool.
381 // The split-verifier is implemented in the VM so it can optionally
382 // and directly resolve constant pool entries to load classes. The
383 // split-verifier can accept either Class entries or UnresolvedClass
384 // entries in the input constant pool. We revert the appended copy
385 // back to UnresolvedClass so that either verifier will be happy
386 // with the constant pool entry.
387 //
388 // this is an indirect CP entry so it needs special handling
389 case JVM_CONSTANT_Class:
390 case JVM_CONSTANT_UnresolvedClass:
391 {
392 int name_i = scratch_cp->klass_name_index_at(scratch_i);
393 int new_name_i = find_or_append_indirect_entry(scratch_cp, name_i, merge_cp_p,
394 merge_cp_length_p);
395
396 if (new_name_i != name_i) {
397 log_trace(redefine, class, constantpool)
398 ("Class entry@%d name_index change: %d to %d",
399 *merge_cp_length_p, name_i, new_name_i);
400 }
401
402 (*merge_cp_p)->temp_unresolved_klass_at_put(*merge_cp_length_p, new_name_i);
403 if (scratch_i != *merge_cp_length_p) {
404 // The new entry in *merge_cp_p is at a different index than
405 // the new entry in scratch_cp so we need to map the index values.
406 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
407 }
408 (*merge_cp_length_p)++;
409 } break;
410
411 // these are direct CP entries so they can be directly appended,
412 // but double and long take two constant pool entries
413 case JVM_CONSTANT_Double: // fall through
414 case JVM_CONSTANT_Long:
415 {
416 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p);
417
418 if (scratch_i != *merge_cp_length_p) {
419 // The new entry in *merge_cp_p is at a different index than
420 // the new entry in scratch_cp so we need to map the index values.
421 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
422 }
423 (*merge_cp_length_p) += 2;
424 } break;
425
426 // these are direct CP entries so they can be directly appended
427 case JVM_CONSTANT_Float: // fall through
428 case JVM_CONSTANT_Integer: // fall through
429 case JVM_CONSTANT_Utf8: // fall through
430
431 // This was an indirect CP entry, but it has been changed into
432 // Symbol*s so this entry can be directly appended.
433 case JVM_CONSTANT_String: // fall through
434 {
435 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p);
436
437 if (scratch_i != *merge_cp_length_p) {
438 // The new entry in *merge_cp_p is at a different index than
439 // the new entry in scratch_cp so we need to map the index values.
440 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
441 }
442 (*merge_cp_length_p)++;
443 } break;
444
445 // this is an indirect CP entry so it needs special handling
446 case JVM_CONSTANT_NameAndType:
447 {
448 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i);
449 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p,
450 merge_cp_length_p);
451
452 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i);
453 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i,
454 merge_cp_p, merge_cp_length_p);
455
456 // If the referenced entries already exist in *merge_cp_p, then
457 // both new_name_ref_i and new_signature_ref_i will both be 0.
458 // In that case, all we are appending is the current entry.
459 if (new_name_ref_i != name_ref_i) {
460 log_trace(redefine, class, constantpool)
461 ("NameAndType entry@%d name_ref_index change: %d to %d",
462 *merge_cp_length_p, name_ref_i, new_name_ref_i);
463 }
464 if (new_signature_ref_i != signature_ref_i) {
465 log_trace(redefine, class, constantpool)
466 ("NameAndType entry@%d signature_ref_index change: %d to %d",
467 *merge_cp_length_p, signature_ref_i, new_signature_ref_i);
468 }
469
470 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p,
471 new_name_ref_i, new_signature_ref_i);
472 if (scratch_i != *merge_cp_length_p) {
473 // The new entry in *merge_cp_p is at a different index than
474 // the new entry in scratch_cp so we need to map the index values.
475 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
476 }
477 (*merge_cp_length_p)++;
478 } break;
479
480 // this is a double-indirect CP entry so it needs special handling
481 case JVM_CONSTANT_Fieldref: // fall through
482 case JVM_CONSTANT_InterfaceMethodref: // fall through
483 case JVM_CONSTANT_Methodref:
484 {
485 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i);
486 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i,
487 merge_cp_p, merge_cp_length_p);
488
489 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i);
490 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i,
491 merge_cp_p, merge_cp_length_p);
492
493 const char *entry_name = nullptr;
494 switch (scratch_cp->tag_at(scratch_i).value()) {
495 case JVM_CONSTANT_Fieldref:
496 entry_name = "Fieldref";
497 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i,
498 new_name_and_type_ref_i);
499 break;
500 case JVM_CONSTANT_InterfaceMethodref:
501 entry_name = "IFMethodref";
502 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p,
503 new_klass_ref_i, new_name_and_type_ref_i);
504 break;
505 case JVM_CONSTANT_Methodref:
506 entry_name = "Methodref";
507 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i,
508 new_name_and_type_ref_i);
509 break;
510 default:
511 guarantee(false, "bad switch");
512 break;
513 }
514
515 if (klass_ref_i != new_klass_ref_i) {
516 log_trace(redefine, class, constantpool)
517 ("%s entry@%d class_index changed: %d to %d", entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i);
518 }
519 if (name_and_type_ref_i != new_name_and_type_ref_i) {
520 log_trace(redefine, class, constantpool)
521 ("%s entry@%d name_and_type_index changed: %d to %d",
522 entry_name, *merge_cp_length_p, name_and_type_ref_i, new_name_and_type_ref_i);
523 }
524
525 if (scratch_i != *merge_cp_length_p) {
526 // The new entry in *merge_cp_p is at a different index than
527 // the new entry in scratch_cp so we need to map the index values.
528 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
529 }
530 (*merge_cp_length_p)++;
531 } break;
532
533 // this is an indirect CP entry so it needs special handling
534 case JVM_CONSTANT_MethodType:
535 {
536 int ref_i = scratch_cp->method_type_index_at(scratch_i);
537 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
538 merge_cp_length_p);
539 if (new_ref_i != ref_i) {
540 log_trace(redefine, class, constantpool)
541 ("MethodType entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i);
542 }
543 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i);
544 if (scratch_i != *merge_cp_length_p) {
545 // The new entry in *merge_cp_p is at a different index than
546 // the new entry in scratch_cp so we need to map the index values.
547 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
548 }
549 (*merge_cp_length_p)++;
550 } break;
551
552 // this is an indirect CP entry so it needs special handling
553 case JVM_CONSTANT_MethodHandle:
554 {
555 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i);
556 int ref_i = scratch_cp->method_handle_index_at(scratch_i);
557 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
558 merge_cp_length_p);
559 if (new_ref_i != ref_i) {
560 log_trace(redefine, class, constantpool)
561 ("MethodHandle entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i);
562 }
563 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i);
564 if (scratch_i != *merge_cp_length_p) {
565 // The new entry in *merge_cp_p is at a different index than
566 // the new entry in scratch_cp so we need to map the index values.
567 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
568 }
569 (*merge_cp_length_p)++;
570 } break;
571
572 // this is an indirect CP entry so it needs special handling
573 case JVM_CONSTANT_Dynamic: // fall through
574 case JVM_CONSTANT_InvokeDynamic:
575 {
576 // Index of the bootstrap specifier in the operands array
577 int old_bs_i = scratch_cp->bootstrap_methods_attribute_index(scratch_i);
578 int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p,
579 merge_cp_length_p);
580 // The bootstrap method NameAndType_info index
581 int old_ref_i = scratch_cp->bootstrap_name_and_type_ref_index_at(scratch_i);
582 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
583 merge_cp_length_p);
584 if (new_bs_i != old_bs_i) {
585 log_trace(redefine, class, constantpool)
586 ("Dynamic entry@%d bootstrap_method_attr_index change: %d to %d",
587 *merge_cp_length_p, old_bs_i, new_bs_i);
588 }
589 if (new_ref_i != old_ref_i) {
590 log_trace(redefine, class, constantpool)
591 ("Dynamic entry@%d name_and_type_index change: %d to %d", *merge_cp_length_p, old_ref_i, new_ref_i);
592 }
593
594 if (scratch_cp->tag_at(scratch_i).is_dynamic_constant())
595 (*merge_cp_p)->dynamic_constant_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
596 else
597 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
598 if (scratch_i != *merge_cp_length_p) {
599 // The new entry in *merge_cp_p is at a different index than
600 // the new entry in scratch_cp so we need to map the index values.
601 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
602 }
603 (*merge_cp_length_p)++;
604 } break;
605
606 // At this stage, Class or UnresolvedClass could be in scratch_cp, but not
607 // ClassIndex
608 case JVM_CONSTANT_ClassIndex: // fall through
609
610 // Invalid is used as the tag for the second constant pool entry
611 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
612 // not be seen by itself.
613 case JVM_CONSTANT_Invalid: // fall through
614
615 // At this stage, String could be here, but not StringIndex
616 case JVM_CONSTANT_StringIndex: // fall through
617
618 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be here
619 case JVM_CONSTANT_UnresolvedClassInError: // fall through
620
621 default:
622 {
623 // leave a breadcrumb
624 jbyte bad_value = scratch_cp->tag_at(scratch_i).value();
625 ShouldNotReachHere();
626 } break;
627 } // end switch tag value
628 } // end append_entry()
629
630
631 u2 VM_RedefineClasses::find_or_append_indirect_entry(const constantPoolHandle& scratch_cp,
632 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) {
633
634 int new_ref_i = ref_i;
635 bool match = (ref_i < *merge_cp_length_p) &&
636 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i);
637
638 if (!match) {
639 // forward reference in *merge_cp_p or not a direct match
640 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p);
641 if (found_i != 0) {
642 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree");
643 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry.
644 new_ref_i = found_i;
645 map_index(scratch_cp, ref_i, found_i);
646 } else {
647 // no match found so we have to append this entry to *merge_cp_p
648 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p);
649 // The above call to append_entry() can only append one entry
650 // so the post call query of *merge_cp_length_p is only for
651 // the sake of consistency.
652 new_ref_i = *merge_cp_length_p - 1;
653 }
654 }
655
656 // constant pool indices are u2, unless the merged constant pool overflows which
657 // we don't check for.
658 return checked_cast<u2>(new_ref_i);
659 } // end find_or_append_indirect_entry()
660
661
662 // Append a bootstrap specifier into the merge_cp operands that is semantically equal
663 // to the scratch_cp operands bootstrap specifier passed by the old_bs_i index.
664 // Recursively append new merge_cp entries referenced by the new bootstrap specifier.
665 void VM_RedefineClasses::append_operand(const constantPoolHandle& scratch_cp, const int old_bs_i,
666 constantPoolHandle *merge_cp_p, int *merge_cp_length_p) {
667
668 BSMAttributeEntry* old_bsme = scratch_cp->bsm_attribute_entry(old_bs_i);
669 u2 old_ref_i = old_bsme->bootstrap_method_index();
670 u2 new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
671 merge_cp_length_p);
672 if (new_ref_i != old_ref_i) {
673 log_trace(redefine, class, constantpool)
674 ("operands entry@%d bootstrap method ref_index change: %d to %d", _operands_cur_length, old_ref_i, new_ref_i);
675 }
676
677 Array<u2>* merge_ops = (*merge_cp_p)->operands();
678 int new_bs_i = _operands_cur_length;
679 // We have _operands_cur_length == 0 when the merge_cp operands is empty yet.
680 // However, the operand_offset_at(0) was set in the extend_operands() call.
681 int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0)
682 : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1);
683 u2 argc = old_bsme->argument_count();
684
685 ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base);
686 merge_ops->at_put(new_base++, new_ref_i);
687 merge_ops->at_put(new_base++, argc);
688
689 for (int i = 0; i < argc; i++) {
690 u2 old_arg_ref_i = old_bsme->argument_index(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 merge_ops->at_put(new_base++, new_arg_ref_i);
694 if (new_arg_ref_i != old_arg_ref_i) {
695 log_trace(redefine, class, constantpool)
696 ("operands entry@%d bootstrap method argument ref_index change: %d to %d",
697 _operands_cur_length, old_arg_ref_i, new_arg_ref_i);
698 }
699 }
700 if (old_bs_i != _operands_cur_length) {
701 // The bootstrap specifier in *merge_cp_p is at a different index than
702 // that in scratch_cp so we need to map the index values.
703 map_operand_index(old_bs_i, new_bs_i);
704 }
705 _operands_cur_length++;
706 } // end append_operand()
707
708
709 int VM_RedefineClasses::find_or_append_operand(const constantPoolHandle& scratch_cp,
710 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) {
711
712 int new_bs_i = old_bs_i; // bootstrap specifier index
713 bool match = (old_bs_i < _operands_cur_length) &&
714 scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i);
715
716 if (!match) {
717 // forward reference in *merge_cp_p or not a direct match
718 int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p,
719 _operands_cur_length);
720 if (found_i != -1) {
721 guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree");
722 // found a matching operand somewhere else in *merge_cp_p so just need a mapping
723 new_bs_i = found_i;
724 map_operand_index(old_bs_i, found_i);
725 } else {
726 // no match found so we have to append this bootstrap specifier to *merge_cp_p
727 append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p);
728 new_bs_i = _operands_cur_length - 1;
729 }
730 }
731 return new_bs_i;
732 } // end find_or_append_operand()
733
734
735 void VM_RedefineClasses::finalize_operands_merge(const constantPoolHandle& merge_cp, TRAPS) {
736 if (merge_cp->operands() == nullptr) {
737 return;
738 }
739 // Shrink the merge_cp operands
740 merge_cp->shrink_operands(_operands_cur_length, 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 < _operands_index_map_p->length(); i++) {
746 int value = _operands_index_map_p->at(i);
747 if (value != -1) {
748 log_trace(redefine, class, constantpool)("operands_index_map[%d]: old=%d new=%d", count, i, value);
749 count++;
750 }
751 }
752 }
753 // Clean-up
754 _operands_index_map_p = nullptr;
755 _operands_cur_length = 0;
756 _operands_index_map_count = 0;
757 } // end finalize_operands_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_operand_index(int old_index) {
1275 if (_operands_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 >= _operands_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 = _operands_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_operand_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 Klass* _scratch_class;
1313 OopHandle _scratch_mirror;
1314
1315 public:
1316
1317 RedefineVerifyMark(Klass* the_class, Klass* 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 size_t 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=%zuK)",
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 }
1490
1491 #ifdef ASSERT
1492 {
1493 // verify what we have done during constant pool merging
1494 {
1495 RedefineVerifyMark rvm(the_class, scratch_class, state);
1496 Verifier::verify(scratch_class, true, THREAD);
1497 }
1498
1499 if (HAS_PENDING_EXCEPTION) {
1500 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1501 log_info(redefine, class, load, exceptions)
1502 ("verify_byte_codes post merge-CP exception: '%s'", ex_name->as_C_string());
1503 CLEAR_PENDING_EXCEPTION;
1504 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1505 return JVMTI_ERROR_OUT_OF_MEMORY;
1506 } else {
1507 // tell the caller that constant pool merging screwed up
1508 return JVMTI_ERROR_INTERNAL;
1509 }
1510 }
1511 }
1512 #endif // ASSERT
1513
1514 Rewriter::rewrite(scratch_class, THREAD);
1515 if (!HAS_PENDING_EXCEPTION) {
1516 scratch_class->link_methods(THREAD);
1517 }
1518 if (HAS_PENDING_EXCEPTION) {
1519 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1520 log_info(redefine, class, load, exceptions)
1521 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string());
1522 CLEAR_PENDING_EXCEPTION;
1523 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1524 return JVMTI_ERROR_OUT_OF_MEMORY;
1525 } else {
1526 return JVMTI_ERROR_INTERNAL;
1527 }
1528 }
1529 // Return value ignored - defaulting to 0 on failure.
1530 (void)os::available_memory(avail_mem);
1531 log_debug(redefine, class, load)
1532 ("loaded name=%s (avail_mem=%zuK)", the_class->external_name(), avail_mem >> 10);
1533 }
1534
1535 return JVMTI_ERROR_NONE;
1536 }
1537
1538
1539 // Map old_index to new_index as needed. scratch_cp is only needed
1540 // for log calls.
1541 void VM_RedefineClasses::map_index(const constantPoolHandle& scratch_cp,
1542 int old_index, int new_index) {
1543 if (find_new_index(old_index) != 0) {
1544 // old_index is already mapped
1545 return;
1546 }
1547
1548 if (old_index == new_index) {
1549 // no mapping is needed
1550 return;
1551 }
1552
1553 _index_map_p->at_put(old_index, new_index);
1554 _index_map_count++;
1555
1556 log_trace(redefine, class, constantpool)
1557 ("mapped tag %d at index %d to %d", scratch_cp->tag_at(old_index).value(), old_index, new_index);
1558 } // end map_index()
1559
1560
1561 // Map old_index to new_index as needed.
1562 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) {
1563 if (find_new_operand_index(old_index) != -1) {
1564 // old_index is already mapped
1565 return;
1566 }
1567
1568 if (old_index == new_index) {
1569 // no mapping is needed
1570 return;
1571 }
1572
1573 _operands_index_map_p->at_put(old_index, new_index);
1574 _operands_index_map_count++;
1575
1576 log_trace(redefine, class, constantpool)("mapped bootstrap specifier at index %d to %d", old_index, new_index);
1577 } // end map_index()
1578
1579
1580 // Merge old_cp and scratch_cp and return the results of the merge via
1581 // merge_cp_p. The number of entries in merge_cp_p is returned via
1582 // merge_cp_length_p. The entries in old_cp occupy the same locations
1583 // in merge_cp_p. Also creates a map of indices from entries in
1584 // scratch_cp to the corresponding entry in merge_cp_p. Index map
1585 // entries are only created for entries in scratch_cp that occupy a
1586 // different location in merged_cp_p.
1587 bool VM_RedefineClasses::merge_constant_pools(const constantPoolHandle& old_cp,
1588 const constantPoolHandle& scratch_cp, constantPoolHandle& merge_cp_p,
1589 int& merge_cp_length_p, TRAPS) {
1590
1591 // Worst case we need old_cp->length() + scratch_cp()->length(),
1592 // but the caller might be smart so make sure we have at least
1593 // the minimum.
1594 if (merge_cp_p->length() < old_cp->length()) {
1595 assert(false, "merge area too small");
1596 return false; // robustness
1597 }
1598
1599 log_info(redefine, class, constantpool)("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(), scratch_cp->length());
1600
1601 {
1602 // Pass 0:
1603 // The old_cp is copied to *merge_cp_p; this means that any code
1604 // using old_cp does not have to change. This work looks like a
1605 // perfect fit for ConstantPool*::copy_cp_to(), but we need to
1606 // handle one special case:
1607 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass
1608 // This will make verification happy.
1609
1610 int old_i; // index into old_cp
1611
1612 // index zero (0) is not used in constantPools
1613 for (old_i = 1; old_i < old_cp->length(); old_i++) {
1614 // leave debugging crumb
1615 jbyte old_tag = old_cp->tag_at(old_i).value();
1616 switch (old_tag) {
1617 case JVM_CONSTANT_Class:
1618 case JVM_CONSTANT_UnresolvedClass:
1619 // revert the copy to JVM_CONSTANT_UnresolvedClass
1620 // May be resolving while calling this so do the same for
1621 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition)
1622 merge_cp_p->temp_unresolved_klass_at_put(old_i,
1623 old_cp->klass_name_index_at(old_i));
1624 break;
1625
1626 case JVM_CONSTANT_Double:
1627 case JVM_CONSTANT_Long:
1628 // just copy the entry to merge_cp_p, but double and long take
1629 // two constant pool entries
1630 ConstantPool::copy_entry_to(old_cp, old_i, merge_cp_p, old_i);
1631 old_i++;
1632 break;
1633
1634 default:
1635 // just copy the entry to merge_cp_p
1636 ConstantPool::copy_entry_to(old_cp, old_i, merge_cp_p, old_i);
1637 break;
1638 }
1639 } // end for each old_cp entry
1640
1641 ConstantPool::copy_operands(old_cp, merge_cp_p, CHECK_false);
1642 merge_cp_p->extend_operands(scratch_cp, CHECK_false);
1643
1644 // We don't need to sanity check that *merge_cp_length_p is within
1645 // *merge_cp_p bounds since we have the minimum on-entry check above.
1646 merge_cp_length_p = old_i;
1647 }
1648
1649 // merge_cp_len should be the same as old_cp->length() at this point
1650 // so this trace message is really a "warm-and-breathing" message.
1651 log_debug(redefine, class, constantpool)("after pass 0: merge_cp_len=%d", merge_cp_length_p);
1652
1653 int scratch_i; // index into scratch_cp
1654 {
1655 // Pass 1a:
1656 // Compare scratch_cp entries to the old_cp entries that we have
1657 // already copied to *merge_cp_p. In this pass, we are eliminating
1658 // exact duplicates (matching entry at same index) so we only
1659 // compare entries in the common indice range.
1660 int increment = 1;
1661 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length());
1662 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) {
1663 switch (scratch_cp->tag_at(scratch_i).value()) {
1664 case JVM_CONSTANT_Double:
1665 case JVM_CONSTANT_Long:
1666 // double and long take two constant pool entries
1667 increment = 2;
1668 break;
1669
1670 default:
1671 increment = 1;
1672 break;
1673 }
1674
1675 bool match = scratch_cp->compare_entry_to(scratch_i, merge_cp_p, scratch_i);
1676 if (match) {
1677 // found a match at the same index so nothing more to do
1678 continue;
1679 }
1680
1681 int found_i = scratch_cp->find_matching_entry(scratch_i, merge_cp_p);
1682 if (found_i != 0) {
1683 guarantee(found_i != scratch_i,
1684 "compare_entry_to() and find_matching_entry() do not agree");
1685
1686 // Found a matching entry somewhere else in *merge_cp_p so
1687 // just need a mapping entry.
1688 map_index(scratch_cp, scratch_i, found_i);
1689 continue;
1690 }
1691
1692 // No match found so we have to append this entry and any unique
1693 // referenced entries to merge_cp_p.
1694 append_entry(scratch_cp, scratch_i, &merge_cp_p, &merge_cp_length_p);
1695 }
1696 }
1697
1698 log_debug(redefine, class, constantpool)
1699 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1700 merge_cp_length_p, scratch_i, _index_map_count);
1701
1702 if (scratch_i < scratch_cp->length()) {
1703 // Pass 1b:
1704 // old_cp is smaller than scratch_cp so there are entries in
1705 // scratch_cp that we have not yet processed. We take care of
1706 // those now.
1707 int increment = 1;
1708 for (; scratch_i < scratch_cp->length(); scratch_i += increment) {
1709 switch (scratch_cp->tag_at(scratch_i).value()) {
1710 case JVM_CONSTANT_Double:
1711 case JVM_CONSTANT_Long:
1712 // double and long take two constant pool entries
1713 increment = 2;
1714 break;
1715
1716 default:
1717 increment = 1;
1718 break;
1719 }
1720
1721 int found_i =
1722 scratch_cp->find_matching_entry(scratch_i, merge_cp_p);
1723 if (found_i != 0) {
1724 // Found a matching entry somewhere else in merge_cp_p so
1725 // just need a mapping entry.
1726 map_index(scratch_cp, scratch_i, found_i);
1727 continue;
1728 }
1729
1730 // No match found so we have to append this entry and any unique
1731 // referenced entries to merge_cp_p.
1732 append_entry(scratch_cp, scratch_i, &merge_cp_p, &merge_cp_length_p);
1733 }
1734
1735 log_debug(redefine, class, constantpool)
1736 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1737 merge_cp_length_p, scratch_i, _index_map_count);
1738 }
1739 finalize_operands_merge(merge_cp_p, CHECK_false);
1740
1741 return true;
1742 } // end merge_constant_pools()
1743
1744
1745 // Scoped object to clean up the constant pool(s) created for merging
1746 class MergeCPCleaner {
1747 ClassLoaderData* _loader_data;
1748 ConstantPool* _cp;
1749 ConstantPool* _scratch_cp;
1750 public:
1751 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) :
1752 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(nullptr) {}
1753 ~MergeCPCleaner() {
1754 _loader_data->add_to_deallocate_list(_cp);
1755 if (_scratch_cp != nullptr) {
1756 _loader_data->add_to_deallocate_list(_scratch_cp);
1757 }
1758 }
1759 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; }
1760 };
1761
1762 // Merge constant pools between the_class and scratch_class and
1763 // potentially rewrite bytecodes in scratch_class to use the merged
1764 // constant pool.
1765 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite(
1766 InstanceKlass* the_class, InstanceKlass* scratch_class,
1767 TRAPS) {
1768 // worst case merged constant pool length is old and new combined
1769 int merge_cp_length = the_class->constants()->length()
1770 + scratch_class->constants()->length();
1771
1772 // Constant pools are not easily reused so we allocate a new one
1773 // each time.
1774 // merge_cp is created unsafe for concurrent GC processing. It
1775 // should be marked safe before discarding it. Even though
1776 // garbage, if it crosses a card boundary, it may be scanned
1777 // in order to find the start of the first complete object on the card.
1778 ClassLoaderData* loader_data = the_class->class_loader_data();
1779 ConstantPool* merge_cp_oop =
1780 ConstantPool::allocate(loader_data,
1781 merge_cp_length,
1782 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1783 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop);
1784
1785 HandleMark hm(THREAD); // make sure handles are cleared before
1786 // MergeCPCleaner clears out merge_cp_oop
1787 constantPoolHandle merge_cp(THREAD, merge_cp_oop);
1788
1789 // Get constants() from the old class because it could have been rewritten
1790 // while we were at a safepoint allocating a new constant pool.
1791 constantPoolHandle old_cp(THREAD, the_class->constants());
1792 constantPoolHandle scratch_cp(THREAD, scratch_class->constants());
1793
1794 // If the length changed, the class was redefined out from under us. Return
1795 // an error.
1796 if (merge_cp_length != the_class->constants()->length()
1797 + scratch_class->constants()->length()) {
1798 return JVMTI_ERROR_INTERNAL;
1799 }
1800
1801 // Update the version number of the constant pools (may keep scratch_cp)
1802 merge_cp->increment_and_save_version(old_cp->version());
1803 scratch_cp->increment_and_save_version(old_cp->version());
1804
1805 ResourceMark rm(THREAD);
1806 _index_map_count = 0;
1807 _index_map_p = new intArray(scratch_cp->length(), scratch_cp->length(), -1);
1808
1809 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands());
1810 _operands_index_map_count = 0;
1811 int operands_index_map_len = ConstantPool::operand_array_length(scratch_cp->operands());
1812 _operands_index_map_p = new intArray(operands_index_map_len, operands_index_map_len, -1);
1813
1814 // reference to the cp holder is needed for copy_operands()
1815 merge_cp->set_pool_holder(scratch_class);
1816 bool result = merge_constant_pools(old_cp, scratch_cp, merge_cp,
1817 merge_cp_length, THREAD);
1818 merge_cp->set_pool_holder(nullptr);
1819
1820 if (!result) {
1821 // The merge can fail due to memory allocation failure or due
1822 // to robustness checks.
1823 return JVMTI_ERROR_INTERNAL;
1824 }
1825
1826 // ensure merged constant pool size does not overflow u2
1827 if (merge_cp_length > 0xFFFF) {
1828 log_warning(redefine, class, constantpool)("Merged constant pool overflow: %d entries", merge_cp_length);
1829 return JVMTI_ERROR_INTERNAL;
1830 }
1831
1832 // Set dynamic constants attribute from the original CP.
1833 if (old_cp->has_dynamic_constant()) {
1834 scratch_cp->set_has_dynamic_constant();
1835 }
1836
1837 log_info(redefine, class, constantpool)("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count);
1838
1839 if (_index_map_count == 0) {
1840 // there is nothing to map between the new and merged constant pools
1841
1842 // Copy attributes from scratch_cp to merge_cp
1843 merge_cp->copy_fields(scratch_cp());
1844
1845 if (old_cp->length() == scratch_cp->length()) {
1846 // The old and new constant pools are the same length and the
1847 // index map is empty. This means that the three constant pools
1848 // are equivalent (but not the same). Unfortunately, the new
1849 // constant pool has not gone through link resolution nor have
1850 // the new class bytecodes gone through constant pool cache
1851 // rewriting so we can't use the old constant pool with the new
1852 // class.
1853
1854 // toss the merged constant pool at return
1855 } else if (old_cp->length() < scratch_cp->length()) {
1856 // The old constant pool has fewer entries than the new constant
1857 // pool and the index map is empty. This means the new constant
1858 // pool is a superset of the old constant pool. However, the old
1859 // class bytecodes have already gone through constant pool cache
1860 // rewriting so we can't use the new constant pool with the old
1861 // class.
1862
1863 // toss the merged constant pool at return
1864 } else {
1865 // The old constant pool has more entries than the new constant
1866 // pool and the index map is empty. This means that both the old
1867 // and merged constant pools are supersets of the new constant
1868 // pool.
1869
1870 // Replace the new constant pool with a shrunken copy of the
1871 // merged constant pool
1872 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1873 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1874 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1875 // It can't be cleaned up while there are handles to it.
1876 cp_cleaner.add_scratch_cp(scratch_cp());
1877 }
1878 } else {
1879 if (log_is_enabled(Trace, redefine, class, constantpool)) {
1880 // don't want to loop unless we are tracing
1881 int count = 0;
1882 for (int i = 1; i < _index_map_p->length(); i++) {
1883 int value = _index_map_p->at(i);
1884
1885 if (value != -1) {
1886 log_trace(redefine, class, constantpool)("index_map[%d]: old=%d new=%d", count, i, value);
1887 count++;
1888 }
1889 }
1890 }
1891
1892 // We have entries mapped between the new and merged constant pools
1893 // so we have to rewrite some constant pool references.
1894 if (!rewrite_cp_refs(scratch_class)) {
1895 return JVMTI_ERROR_INTERNAL;
1896 }
1897
1898 // Copy attributes from scratch_cp to merge_cp (should be done after rewrite_cp_refs())
1899 merge_cp->copy_fields(scratch_cp());
1900
1901 // Replace the new constant pool with a shrunken copy of the
1902 // merged constant pool so now the rewritten bytecodes have
1903 // valid references; the previous new constant pool will get
1904 // GCed.
1905 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1906 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1907 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1908 // It can't be cleaned up while there are handles to it.
1909 cp_cleaner.add_scratch_cp(scratch_cp());
1910 }
1911
1912 return JVMTI_ERROR_NONE;
1913 } // end merge_cp_and_rewrite()
1914
1915
1916 // Rewrite constant pool references in klass scratch_class.
1917 bool VM_RedefineClasses::rewrite_cp_refs(InstanceKlass* scratch_class) {
1918
1919 // rewrite constant pool references in the nest attributes:
1920 if (!rewrite_cp_refs_in_nest_attributes(scratch_class)) {
1921 // propagate failure back to caller
1922 return false;
1923 }
1924
1925 // rewrite constant pool references in the Record attribute:
1926 if (!rewrite_cp_refs_in_record_attribute(scratch_class)) {
1927 // propagate failure back to caller
1928 return false;
1929 }
1930
1931 // rewrite constant pool references in the PermittedSubclasses attribute:
1932 if (!rewrite_cp_refs_in_permitted_subclasses_attribute(scratch_class)) {
1933 // propagate failure back to caller
1934 return false;
1935 }
1936
1937 // rewrite constant pool references in the LoadableDescriptors attribute:
1938 if (!rewrite_cp_refs_in_loadable_descriptors_attribute(scratch_class)) {
1939 // propagate failure back to caller
1940 return false;
1941 }
1942
1943 // rewrite constant pool references in the methods:
1944 if (!rewrite_cp_refs_in_methods(scratch_class)) {
1945 // propagate failure back to caller
1946 return false;
1947 }
1948
1949 // rewrite constant pool references in the class_annotations:
1950 if (!rewrite_cp_refs_in_class_annotations(scratch_class)) {
1951 // propagate failure back to caller
1952 return false;
1953 }
1954
1955 // rewrite constant pool references in the fields_annotations:
1956 if (!rewrite_cp_refs_in_fields_annotations(scratch_class)) {
1957 // propagate failure back to caller
1958 return false;
1959 }
1960
1961 // rewrite constant pool references in the methods_annotations:
1962 if (!rewrite_cp_refs_in_methods_annotations(scratch_class)) {
1963 // propagate failure back to caller
1964 return false;
1965 }
1966
1967 // rewrite constant pool references in the methods_parameter_annotations:
1968 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class)) {
1969 // propagate failure back to caller
1970 return false;
1971 }
1972
1973 // rewrite constant pool references in the methods_default_annotations:
1974 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class)) {
1975 // propagate failure back to caller
1976 return false;
1977 }
1978
1979 // rewrite constant pool references in the class_type_annotations:
1980 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class)) {
1981 // propagate failure back to caller
1982 return false;
1983 }
1984
1985 // rewrite constant pool references in the fields_type_annotations:
1986 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class)) {
1987 // propagate failure back to caller
1988 return false;
1989 }
1990
1991 // rewrite constant pool references in the methods_type_annotations:
1992 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class)) {
1993 // propagate failure back to caller
1994 return false;
1995 }
1996
1997 // There can be type annotations in the Code part of a method_info attribute.
1998 // These annotations are not accessible, even by reflection.
1999 // Currently they are not even parsed by the ClassFileParser.
2000 // If runtime access is added they will also need to be rewritten.
2001
2002 // rewrite source file name index:
2003 u2 source_file_name_idx = scratch_class->source_file_name_index();
2004 if (source_file_name_idx != 0) {
2005 u2 new_source_file_name_idx = find_new_index(source_file_name_idx);
2006 if (new_source_file_name_idx != 0) {
2007 scratch_class->set_source_file_name_index(new_source_file_name_idx);
2008 }
2009 }
2010
2011 // rewrite class generic signature index:
2012 u2 generic_signature_index = scratch_class->generic_signature_index();
2013 if (generic_signature_index != 0) {
2014 u2 new_generic_signature_index = find_new_index(generic_signature_index);
2015 if (new_generic_signature_index != 0) {
2016 scratch_class->set_generic_signature_index(new_generic_signature_index);
2017 }
2018 }
2019
2020 return true;
2021 } // end rewrite_cp_refs()
2022
2023 // Rewrite constant pool references in the NestHost and NestMembers attributes.
2024 bool VM_RedefineClasses::rewrite_cp_refs_in_nest_attributes(
2025 InstanceKlass* scratch_class) {
2026
2027 u2 cp_index = scratch_class->nest_host_index();
2028 if (cp_index != 0) {
2029 scratch_class->set_nest_host_index(find_new_index(cp_index));
2030 }
2031 Array<u2>* nest_members = scratch_class->nest_members();
2032 for (int i = 0; i < nest_members->length(); i++) {
2033 u2 cp_index = nest_members->at(i);
2034 nest_members->at_put(i, find_new_index(cp_index));
2035 }
2036 return true;
2037 }
2038
2039 // Rewrite constant pool references in the Record attribute.
2040 bool VM_RedefineClasses::rewrite_cp_refs_in_record_attribute(InstanceKlass* scratch_class) {
2041 Array<RecordComponent*>* components = scratch_class->record_components();
2042 if (components != nullptr) {
2043 for (int i = 0; i < components->length(); i++) {
2044 RecordComponent* component = components->at(i);
2045 u2 cp_index = component->name_index();
2046 component->set_name_index(find_new_index(cp_index));
2047 cp_index = component->descriptor_index();
2048 component->set_descriptor_index(find_new_index(cp_index));
2049 cp_index = component->generic_signature_index();
2050 if (cp_index != 0) {
2051 component->set_generic_signature_index(find_new_index(cp_index));
2052 }
2053
2054 AnnotationArray* annotations = component->annotations();
2055 if (annotations != nullptr && annotations->length() != 0) {
2056 int byte_i = 0; // byte index into annotations
2057 if (!rewrite_cp_refs_in_annotations_typeArray(annotations, byte_i)) {
2058 log_debug(redefine, class, annotation)("bad record_component_annotations at %d", i);
2059 // propagate failure back to caller
2060 return false;
2061 }
2062 }
2063
2064 AnnotationArray* type_annotations = component->type_annotations();
2065 if (type_annotations != nullptr && type_annotations->length() != 0) {
2066 int byte_i = 0; // byte index into annotations
2067 if (!rewrite_cp_refs_in_annotations_typeArray(type_annotations, byte_i)) {
2068 log_debug(redefine, class, annotation)("bad record_component_type_annotations at %d", i);
2069 // propagate failure back to caller
2070 return false;
2071 }
2072 }
2073 }
2074 }
2075 return true;
2076 }
2077
2078 // Rewrite constant pool references in the PermittedSubclasses attribute.
2079 bool VM_RedefineClasses::rewrite_cp_refs_in_permitted_subclasses_attribute(
2080 InstanceKlass* scratch_class) {
2081
2082 Array<u2>* permitted_subclasses = scratch_class->permitted_subclasses();
2083 assert(permitted_subclasses != nullptr, "unexpected null permitted_subclasses");
2084 for (int i = 0; i < permitted_subclasses->length(); i++) {
2085 u2 cp_index = permitted_subclasses->at(i);
2086 permitted_subclasses->at_put(i, find_new_index(cp_index));
2087 }
2088 return true;
2089 }
2090
2091 // Rewrite constant pool references in the LoadableDescriptors attribute.
2092 bool VM_RedefineClasses::rewrite_cp_refs_in_loadable_descriptors_attribute(
2093 InstanceKlass* scratch_class) {
2094
2095 Array<u2>* loadable_descriptors = scratch_class->loadable_descriptors();
2096 assert(loadable_descriptors != nullptr, "unexpected null loadable_descriptors");
2097 for (int i = 0; i < loadable_descriptors->length(); i++) {
2098 u2 cp_index = loadable_descriptors->at(i);
2099 loadable_descriptors->at_put(i, find_new_index(cp_index));
2100 }
2101 return true;
2102 }
2103
2104 // Rewrite constant pool references in the methods.
2105 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(InstanceKlass* scratch_class) {
2106
2107 Array<Method*>* methods = scratch_class->methods();
2108
2109 if (methods == nullptr || methods->length() == 0) {
2110 // no methods so nothing to do
2111 return true;
2112 }
2113
2114 JavaThread* THREAD = JavaThread::current(); // For exception macros.
2115 ExceptionMark em(THREAD);
2116
2117 // rewrite constant pool references in the methods:
2118 for (int i = methods->length() - 1; i >= 0; i--) {
2119 methodHandle method(THREAD, methods->at(i));
2120 methodHandle new_method;
2121 rewrite_cp_refs_in_method(method, &new_method, THREAD);
2122 if (!new_method.is_null()) {
2123 // the method has been replaced so save the new method version
2124 // even in the case of an exception. original method is on the
2125 // deallocation list.
2126 methods->at_put(i, new_method());
2127 }
2128 if (HAS_PENDING_EXCEPTION) {
2129 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
2130 log_info(redefine, class, load, exceptions)("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string());
2131 // Need to clear pending exception here as the super caller sets
2132 // the JVMTI_ERROR_INTERNAL if the returned value is false.
2133 CLEAR_PENDING_EXCEPTION;
2134 return false;
2135 }
2136 }
2137
2138 return true;
2139 }
2140
2141
2142 // Rewrite constant pool references in the specific method. This code
2143 // was adapted from Rewriter::rewrite_method().
2144 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method,
2145 methodHandle *new_method_p, TRAPS) {
2146
2147 *new_method_p = methodHandle(); // default is no new method
2148
2149 // We cache a pointer to the bytecodes here in code_base. If GC
2150 // moves the Method*, then the bytecodes will also move which
2151 // will likely cause a crash. We create a NoSafepointVerifier
2152 // object to detect whether we pass a possible safepoint in this
2153 // code block.
2154 NoSafepointVerifier nsv;
2155
2156 // Bytecodes and their length
2157 address code_base = method->code_base();
2158 int code_length = method->code_size();
2159
2160 int bc_length;
2161 for (int bci = 0; bci < code_length; bci += bc_length) {
2162 address bcp = code_base + bci;
2163 Bytecodes::Code c = (Bytecodes::Code)(*bcp);
2164
2165 bc_length = Bytecodes::length_for(c);
2166 if (bc_length == 0) {
2167 // More complicated bytecodes report a length of zero so
2168 // we have to try again a slightly different way.
2169 bc_length = Bytecodes::length_at(method(), bcp);
2170 }
2171
2172 assert(bc_length != 0, "impossible bytecode length");
2173
2174 switch (c) {
2175 case Bytecodes::_ldc:
2176 {
2177 u1 cp_index = *(bcp + 1);
2178 u2 new_index = find_new_index(cp_index);
2179
2180 if (StressLdcRewrite && new_index == 0) {
2181 // If we are stressing ldc -> ldc_w rewriting, then we
2182 // always need a new_index value.
2183 new_index = cp_index;
2184 }
2185 if (new_index != 0) {
2186 // the original index is mapped so we have more work to do
2187 if (!StressLdcRewrite && new_index <= max_jubyte) {
2188 // The new value can still use ldc instead of ldc_w
2189 // unless we are trying to stress ldc -> ldc_w rewriting
2190 log_trace(redefine, class, constantpool)
2191 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index);
2192 // We checked that new_index fits in a u1 so this cast is safe
2193 *(bcp + 1) = (u1)new_index;
2194 } else {
2195 log_trace(redefine, class, constantpool)
2196 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index);
2197 // the new value needs ldc_w instead of ldc
2198 u_char inst_buffer[4]; // max instruction size is 4 bytes
2199 bcp = (address)inst_buffer;
2200 // construct new instruction sequence
2201 *bcp = Bytecodes::_ldc_w;
2202 bcp++;
2203 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w.
2204 // See comment below for difference between put_Java_u2()
2205 // and put_native_u2().
2206 Bytes::put_Java_u2(bcp, new_index);
2207
2208 Relocator rc(method, nullptr /* no RelocatorListener needed */);
2209 methodHandle m;
2210 {
2211 PauseNoSafepointVerifier pnsv(&nsv);
2212
2213 // ldc is 2 bytes and ldc_w is 3 bytes
2214 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK);
2215 }
2216
2217 // return the new method so that the caller can update
2218 // the containing class
2219 *new_method_p = method = m;
2220 // switch our bytecode processing loop from the old method
2221 // to the new method
2222 code_base = method->code_base();
2223 code_length = method->code_size();
2224 bcp = code_base + bci;
2225 c = (Bytecodes::Code)(*bcp);
2226 bc_length = Bytecodes::length_for(c);
2227 assert(bc_length != 0, "sanity check");
2228 } // end we need ldc_w instead of ldc
2229 } // end if there is a mapped index
2230 } break;
2231
2232 // these bytecodes have a two-byte constant pool index
2233 case Bytecodes::_anewarray : // fall through
2234 case Bytecodes::_checkcast : // fall through
2235 case Bytecodes::_getfield : // fall through
2236 case Bytecodes::_getstatic : // fall through
2237 case Bytecodes::_instanceof : // fall through
2238 case Bytecodes::_invokedynamic : // fall through
2239 case Bytecodes::_invokeinterface: // fall through
2240 case Bytecodes::_invokespecial : // fall through
2241 case Bytecodes::_invokestatic : // fall through
2242 case Bytecodes::_invokevirtual : // fall through
2243 case Bytecodes::_ldc_w : // fall through
2244 case Bytecodes::_ldc2_w : // fall through
2245 case Bytecodes::_multianewarray : // fall through
2246 case Bytecodes::_new : // fall through
2247 case Bytecodes::_putfield : // fall through
2248 case Bytecodes::_putstatic :
2249 {
2250 address p = bcp + 1;
2251 int cp_index = Bytes::get_Java_u2(p);
2252 u2 new_index = find_new_index(cp_index);
2253 if (new_index != 0) {
2254 // the original index is mapped so update w/ new value
2255 log_trace(redefine, class, constantpool)
2256 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),p2i(bcp), cp_index, new_index);
2257 // Rewriter::rewrite_method() uses put_native_u2() in this
2258 // situation because it is reusing the constant pool index
2259 // location for a native index into the ConstantPoolCache.
2260 // Since we are updating the constant pool index prior to
2261 // verification and ConstantPoolCache initialization, we
2262 // need to keep the new index in Java byte order.
2263 Bytes::put_Java_u2(p, new_index);
2264 }
2265 } break;
2266 default:
2267 break;
2268 }
2269 } // end for each bytecode
2270 } // end rewrite_cp_refs_in_method()
2271
2272
2273 // Rewrite constant pool references in the class_annotations field.
2274 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(InstanceKlass* scratch_class) {
2275
2276 AnnotationArray* class_annotations = scratch_class->class_annotations();
2277 if (class_annotations == nullptr || class_annotations->length() == 0) {
2278 // no class_annotations so nothing to do
2279 return true;
2280 }
2281
2282 log_debug(redefine, class, annotation)("class_annotations length=%d", class_annotations->length());
2283
2284 int byte_i = 0; // byte index into class_annotations
2285 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i);
2286 }
2287
2288
2289 // Rewrite constant pool references in an annotations typeArray. This
2290 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute
2291 // that is described in section 4.8.15 of the 2nd-edition of the VM spec:
2292 //
2293 // annotations_typeArray {
2294 // u2 num_annotations;
2295 // annotation annotations[num_annotations];
2296 // }
2297 //
2298 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray(
2299 AnnotationArray* annotations_typeArray, int &byte_i_ref) {
2300
2301 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2302 // not enough room for num_annotations field
2303 log_debug(redefine, class, annotation)("length() is too small for num_annotations field");
2304 return false;
2305 }
2306
2307 u2 num_annotations = Bytes::get_Java_u2((address)
2308 annotations_typeArray->adr_at(byte_i_ref));
2309 byte_i_ref += 2;
2310
2311 log_debug(redefine, class, annotation)("num_annotations=%d", num_annotations);
2312
2313 int calc_num_annotations = 0;
2314 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
2315 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, byte_i_ref)) {
2316 log_debug(redefine, class, annotation)("bad annotation_struct at %d", calc_num_annotations);
2317 // propagate failure back to caller
2318 return false;
2319 }
2320 }
2321 assert(num_annotations == calc_num_annotations, "sanity check");
2322
2323 return true;
2324 } // end rewrite_cp_refs_in_annotations_typeArray()
2325
2326
2327 // Rewrite constant pool references in the annotation struct portion of
2328 // an annotations_typeArray. This "structure" is from section 4.8.15 of
2329 // the 2nd-edition of the VM spec:
2330 //
2331 // struct annotation {
2332 // u2 type_index;
2333 // u2 num_element_value_pairs;
2334 // {
2335 // u2 element_name_index;
2336 // element_value value;
2337 // } element_value_pairs[num_element_value_pairs];
2338 // }
2339 //
2340 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct(
2341 AnnotationArray* annotations_typeArray, int &byte_i_ref) {
2342 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) {
2343 // not enough room for smallest annotation_struct
2344 log_debug(redefine, class, annotation)("length() is too small for annotation_struct");
2345 return false;
2346 }
2347
2348 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray,
2349 byte_i_ref, "type_index");
2350
2351 u2 num_element_value_pairs = Bytes::get_Java_u2((address)
2352 annotations_typeArray->adr_at(byte_i_ref));
2353 byte_i_ref += 2;
2354
2355 log_debug(redefine, class, annotation)
2356 ("type_index=%d num_element_value_pairs=%d", type_index, num_element_value_pairs);
2357
2358 int calc_num_element_value_pairs = 0;
2359 for (; calc_num_element_value_pairs < num_element_value_pairs;
2360 calc_num_element_value_pairs++) {
2361 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2362 // not enough room for another element_name_index, let alone
2363 // the rest of another component
2364 log_debug(redefine, class, annotation)("length() is too small for element_name_index");
2365 return false;
2366 }
2367
2368 u2 element_name_index = rewrite_cp_ref_in_annotation_data(
2369 annotations_typeArray, byte_i_ref,
2370 "element_name_index");
2371
2372 log_debug(redefine, class, annotation)("element_name_index=%d", element_name_index);
2373
2374 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, byte_i_ref)) {
2375 log_debug(redefine, class, annotation)("bad element_value at %d", calc_num_element_value_pairs);
2376 // propagate failure back to caller
2377 return false;
2378 }
2379 } // end for each component
2380 assert(num_element_value_pairs == calc_num_element_value_pairs,
2381 "sanity check");
2382
2383 return true;
2384 } // end rewrite_cp_refs_in_annotation_struct()
2385
2386
2387 // Rewrite a constant pool reference at the current position in
2388 // annotations_typeArray if needed. Returns the original constant
2389 // pool reference if a rewrite was not needed or the new constant
2390 // pool reference if a rewrite was needed.
2391 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data(
2392 AnnotationArray* annotations_typeArray, int &byte_i_ref,
2393 const char * trace_mesg) {
2394
2395 address cp_index_addr = (address)
2396 annotations_typeArray->adr_at(byte_i_ref);
2397 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr);
2398 u2 new_cp_index = find_new_index(old_cp_index);
2399 if (new_cp_index != 0) {
2400 log_debug(redefine, class, annotation)("mapped old %s=%d", trace_mesg, old_cp_index);
2401 Bytes::put_Java_u2(cp_index_addr, new_cp_index);
2402 old_cp_index = new_cp_index;
2403 }
2404 byte_i_ref += 2;
2405 return old_cp_index;
2406 }
2407
2408
2409 // Rewrite constant pool references in the element_value portion of an
2410 // annotations_typeArray. This "structure" is from section 4.8.15.1 of
2411 // the 2nd-edition of the VM spec:
2412 //
2413 // struct element_value {
2414 // u1 tag;
2415 // union {
2416 // u2 const_value_index;
2417 // {
2418 // u2 type_name_index;
2419 // u2 const_name_index;
2420 // } enum_const_value;
2421 // u2 class_info_index;
2422 // annotation annotation_value;
2423 // struct {
2424 // u2 num_values;
2425 // element_value values[num_values];
2426 // } array_value;
2427 // } value;
2428 // }
2429 //
2430 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value(
2431 AnnotationArray* annotations_typeArray, int &byte_i_ref) {
2432
2433 if ((byte_i_ref + 1) > annotations_typeArray->length()) {
2434 // not enough room for a tag let alone the rest of an element_value
2435 log_debug(redefine, class, annotation)("length() is too small for a tag");
2436 return false;
2437 }
2438
2439 u1 tag = annotations_typeArray->at(byte_i_ref);
2440 byte_i_ref++;
2441 log_debug(redefine, class, annotation)("tag='%c'", tag);
2442
2443 switch (tag) {
2444 // These BaseType tag values are from Table 4.2 in VM spec:
2445 case JVM_SIGNATURE_BYTE:
2446 case JVM_SIGNATURE_CHAR:
2447 case JVM_SIGNATURE_DOUBLE:
2448 case JVM_SIGNATURE_FLOAT:
2449 case JVM_SIGNATURE_INT:
2450 case JVM_SIGNATURE_LONG:
2451 case JVM_SIGNATURE_SHORT:
2452 case JVM_SIGNATURE_BOOLEAN:
2453
2454 // The remaining tag values are from Table 4.8 in the 2nd-edition of
2455 // the VM spec:
2456 case 's':
2457 {
2458 // For the above tag values (including the BaseType values),
2459 // value.const_value_index is right union field.
2460
2461 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2462 // not enough room for a const_value_index
2463 log_debug(redefine, class, annotation)("length() is too small for a const_value_index");
2464 return false;
2465 }
2466
2467 u2 const_value_index = rewrite_cp_ref_in_annotation_data(
2468 annotations_typeArray, byte_i_ref,
2469 "const_value_index");
2470
2471 log_debug(redefine, class, annotation)("const_value_index=%d", const_value_index);
2472 } break;
2473
2474 case 'e':
2475 {
2476 // for the above tag value, value.enum_const_value is right union field
2477
2478 if ((byte_i_ref + 4) > annotations_typeArray->length()) {
2479 // not enough room for a enum_const_value
2480 log_debug(redefine, class, annotation)("length() is too small for a enum_const_value");
2481 return false;
2482 }
2483
2484 u2 type_name_index = rewrite_cp_ref_in_annotation_data(
2485 annotations_typeArray, byte_i_ref,
2486 "type_name_index");
2487
2488 u2 const_name_index = rewrite_cp_ref_in_annotation_data(
2489 annotations_typeArray, byte_i_ref,
2490 "const_name_index");
2491
2492 log_debug(redefine, class, annotation)
2493 ("type_name_index=%d const_name_index=%d", type_name_index, const_name_index);
2494 } break;
2495
2496 case 'c':
2497 {
2498 // for the above tag value, value.class_info_index is right union field
2499
2500 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2501 // not enough room for a class_info_index
2502 log_debug(redefine, class, annotation)("length() is too small for a class_info_index");
2503 return false;
2504 }
2505
2506 u2 class_info_index = rewrite_cp_ref_in_annotation_data(
2507 annotations_typeArray, byte_i_ref,
2508 "class_info_index");
2509
2510 log_debug(redefine, class, annotation)("class_info_index=%d", class_info_index);
2511 } break;
2512
2513 case '@':
2514 // For the above tag value, value.attr_value is the right union
2515 // field. This is a nested annotation.
2516 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, byte_i_ref)) {
2517 // propagate failure back to caller
2518 return false;
2519 }
2520 break;
2521
2522 case JVM_SIGNATURE_ARRAY:
2523 {
2524 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2525 // not enough room for a num_values field
2526 log_debug(redefine, class, annotation)("length() is too small for a num_values field");
2527 return false;
2528 }
2529
2530 // For the above tag value, value.array_value is the right union
2531 // field. This is an array of nested element_value.
2532 u2 num_values = Bytes::get_Java_u2((address)
2533 annotations_typeArray->adr_at(byte_i_ref));
2534 byte_i_ref += 2;
2535 log_debug(redefine, class, annotation)("num_values=%d", num_values);
2536
2537 int calc_num_values = 0;
2538 for (; calc_num_values < num_values; calc_num_values++) {
2539 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, byte_i_ref)) {
2540 log_debug(redefine, class, annotation)("bad nested element_value at %d", calc_num_values);
2541 // propagate failure back to caller
2542 return false;
2543 }
2544 }
2545 assert(num_values == calc_num_values, "sanity check");
2546 } break;
2547
2548 default:
2549 log_debug(redefine, class, annotation)("bad tag=0x%x", tag);
2550 return false;
2551 } // end decode tag field
2552
2553 return true;
2554 } // end rewrite_cp_refs_in_element_value()
2555
2556
2557 // Rewrite constant pool references in a fields_annotations field.
2558 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations(
2559 InstanceKlass* scratch_class) {
2560
2561 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations();
2562
2563 if (fields_annotations == nullptr || fields_annotations->length() == 0) {
2564 // no fields_annotations so nothing to do
2565 return true;
2566 }
2567
2568 log_debug(redefine, class, annotation)("fields_annotations length=%d", fields_annotations->length());
2569
2570 for (int i = 0; i < fields_annotations->length(); i++) {
2571 AnnotationArray* field_annotations = fields_annotations->at(i);
2572 if (field_annotations == nullptr || field_annotations->length() == 0) {
2573 // this field does not have any annotations so skip it
2574 continue;
2575 }
2576
2577 int byte_i = 0; // byte index into field_annotations
2578 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i)) {
2579 log_debug(redefine, class, annotation)("bad field_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_fields_annotations()
2587
2588
2589 // Rewrite constant pool references in a methods_annotations field.
2590 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations(
2591 InstanceKlass* scratch_class) {
2592
2593 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2594 Method* m = scratch_class->methods()->at(i);
2595 AnnotationArray* method_annotations = m->constMethod()->method_annotations();
2596
2597 if (method_annotations == nullptr || method_annotations->length() == 0) {
2598 // this method does not have any annotations so skip it
2599 continue;
2600 }
2601
2602 int byte_i = 0; // byte index into method_annotations
2603 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i)) {
2604 log_debug(redefine, class, annotation)("bad method_annotations at %d", i);
2605 // propagate failure back to caller
2606 return false;
2607 }
2608 }
2609
2610 return true;
2611 } // end rewrite_cp_refs_in_methods_annotations()
2612
2613
2614 // Rewrite constant pool references in a methods_parameter_annotations
2615 // field. This "structure" is adapted from the
2616 // RuntimeVisibleParameterAnnotations_attribute described in section
2617 // 4.8.17 of the 2nd-edition of the VM spec:
2618 //
2619 // methods_parameter_annotations_typeArray {
2620 // u1 num_parameters;
2621 // {
2622 // u2 num_annotations;
2623 // annotation annotations[num_annotations];
2624 // } parameter_annotations[num_parameters];
2625 // }
2626 //
2627 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations(
2628 InstanceKlass* scratch_class) {
2629
2630 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2631 Method* m = scratch_class->methods()->at(i);
2632 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations();
2633 if (method_parameter_annotations == nullptr
2634 || method_parameter_annotations->length() == 0) {
2635 // this method does not have any parameter annotations so skip it
2636 continue;
2637 }
2638
2639 if (method_parameter_annotations->length() < 1) {
2640 // not enough room for a num_parameters field
2641 log_debug(redefine, class, annotation)("length() is too small for a num_parameters field at %d", i);
2642 return false;
2643 }
2644
2645 int byte_i = 0; // byte index into method_parameter_annotations
2646
2647 u1 num_parameters = method_parameter_annotations->at(byte_i);
2648 byte_i++;
2649
2650 log_debug(redefine, class, annotation)("num_parameters=%d", num_parameters);
2651
2652 int calc_num_parameters = 0;
2653 for (; calc_num_parameters < num_parameters; calc_num_parameters++) {
2654 if (!rewrite_cp_refs_in_annotations_typeArray(method_parameter_annotations, byte_i)) {
2655 log_debug(redefine, class, annotation)("bad method_parameter_annotations at %d", calc_num_parameters);
2656 // propagate failure back to caller
2657 return false;
2658 }
2659 }
2660 assert(num_parameters == calc_num_parameters, "sanity check");
2661 }
2662
2663 return true;
2664 } // end rewrite_cp_refs_in_methods_parameter_annotations()
2665
2666
2667 // Rewrite constant pool references in a methods_default_annotations
2668 // field. This "structure" is adapted from the AnnotationDefault_attribute
2669 // that is described in section 4.8.19 of the 2nd-edition of the VM spec:
2670 //
2671 // methods_default_annotations_typeArray {
2672 // element_value default_value;
2673 // }
2674 //
2675 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations(
2676 InstanceKlass* scratch_class) {
2677
2678 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2679 Method* m = scratch_class->methods()->at(i);
2680 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations();
2681 if (method_default_annotations == nullptr
2682 || method_default_annotations->length() == 0) {
2683 // this method does not have any default annotations so skip it
2684 continue;
2685 }
2686
2687 int byte_i = 0; // byte index into method_default_annotations
2688
2689 if (!rewrite_cp_refs_in_element_value(
2690 method_default_annotations, byte_i)) {
2691 log_debug(redefine, class, annotation)("bad default element_value at %d", i);
2692 // propagate failure back to caller
2693 return false;
2694 }
2695 }
2696
2697 return true;
2698 } // end rewrite_cp_refs_in_methods_default_annotations()
2699
2700
2701 // Rewrite constant pool references in a class_type_annotations field.
2702 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations(
2703 InstanceKlass* scratch_class) {
2704
2705 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations();
2706 if (class_type_annotations == nullptr || class_type_annotations->length() == 0) {
2707 // no class_type_annotations so nothing to do
2708 return true;
2709 }
2710
2711 log_debug(redefine, class, annotation)("class_type_annotations length=%d", class_type_annotations->length());
2712
2713 int byte_i = 0; // byte index into class_type_annotations
2714 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations,
2715 byte_i, "ClassFile");
2716 } // end rewrite_cp_refs_in_class_type_annotations()
2717
2718
2719 // Rewrite constant pool references in a fields_type_annotations field.
2720 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations(InstanceKlass* scratch_class) {
2721
2722 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations();
2723 if (fields_type_annotations == nullptr || fields_type_annotations->length() == 0) {
2724 // no fields_type_annotations so nothing to do
2725 return true;
2726 }
2727
2728 log_debug(redefine, class, annotation)("fields_type_annotations length=%d", fields_type_annotations->length());
2729
2730 for (int i = 0; i < fields_type_annotations->length(); i++) {
2731 AnnotationArray* field_type_annotations = fields_type_annotations->at(i);
2732 if (field_type_annotations == nullptr || field_type_annotations->length() == 0) {
2733 // this field does not have any annotations so skip it
2734 continue;
2735 }
2736
2737 int byte_i = 0; // byte index into field_type_annotations
2738 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations,
2739 byte_i, "field_info")) {
2740 log_debug(redefine, class, annotation)("bad field_type_annotations at %d", i);
2741 // propagate failure back to caller
2742 return false;
2743 }
2744 }
2745
2746 return true;
2747 } // end rewrite_cp_refs_in_fields_type_annotations()
2748
2749
2750 // Rewrite constant pool references in a methods_type_annotations field.
2751 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations(
2752 InstanceKlass* scratch_class) {
2753
2754 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2755 Method* m = scratch_class->methods()->at(i);
2756 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations();
2757
2758 if (method_type_annotations == nullptr || method_type_annotations->length() == 0) {
2759 // this method does not have any annotations so skip it
2760 continue;
2761 }
2762
2763 log_debug(redefine, class, annotation)("methods type_annotations length=%d", method_type_annotations->length());
2764
2765 int byte_i = 0; // byte index into method_type_annotations
2766 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations,
2767 byte_i, "method_info")) {
2768 log_debug(redefine, class, annotation)("bad method_type_annotations at %d", i);
2769 // propagate failure back to caller
2770 return false;
2771 }
2772 }
2773
2774 return true;
2775 } // end rewrite_cp_refs_in_methods_type_annotations()
2776
2777
2778 // Rewrite constant pool references in a type_annotations
2779 // field. This "structure" is adapted from the
2780 // RuntimeVisibleTypeAnnotations_attribute described in
2781 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2782 //
2783 // type_annotations_typeArray {
2784 // u2 num_annotations;
2785 // type_annotation annotations[num_annotations];
2786 // }
2787 //
2788 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray(
2789 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2790 const char * location_mesg) {
2791
2792 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2793 // not enough room for num_annotations field
2794 log_debug(redefine, class, annotation)("length() is too small for num_annotations field");
2795 return false;
2796 }
2797
2798 u2 num_annotations = Bytes::get_Java_u2((address)
2799 type_annotations_typeArray->adr_at(byte_i_ref));
2800 byte_i_ref += 2;
2801
2802 log_debug(redefine, class, annotation)("num_type_annotations=%d", num_annotations);
2803
2804 int calc_num_annotations = 0;
2805 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
2806 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray,
2807 byte_i_ref, location_mesg)) {
2808 log_debug(redefine, class, annotation)("bad type_annotation_struct at %d", calc_num_annotations);
2809 // propagate failure back to caller
2810 return false;
2811 }
2812 }
2813 assert(num_annotations == calc_num_annotations, "sanity check");
2814
2815 if (byte_i_ref != type_annotations_typeArray->length()) {
2816 log_debug(redefine, class, annotation)
2817 ("read wrong amount of bytes at end of processing type_annotations_typeArray (%d of %d bytes were read)",
2818 byte_i_ref, type_annotations_typeArray->length());
2819 return false;
2820 }
2821
2822 return true;
2823 } // end rewrite_cp_refs_in_type_annotations_typeArray()
2824
2825
2826 // Rewrite constant pool references in a type_annotation
2827 // field. This "structure" is adapted from the
2828 // RuntimeVisibleTypeAnnotations_attribute described in
2829 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2830 //
2831 // type_annotation {
2832 // u1 target_type;
2833 // union {
2834 // type_parameter_target;
2835 // supertype_target;
2836 // type_parameter_bound_target;
2837 // empty_target;
2838 // method_formal_parameter_target;
2839 // throws_target;
2840 // localvar_target;
2841 // catch_target;
2842 // offset_target;
2843 // type_argument_target;
2844 // } target_info;
2845 // type_path target_path;
2846 // annotation anno;
2847 // }
2848 //
2849 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct(
2850 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2851 const char * location_mesg) {
2852
2853 if (!skip_type_annotation_target(type_annotations_typeArray,
2854 byte_i_ref, location_mesg)) {
2855 return false;
2856 }
2857
2858 if (!skip_type_annotation_type_path(type_annotations_typeArray, byte_i_ref)) {
2859 return false;
2860 }
2861
2862 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray, byte_i_ref)) {
2863 return false;
2864 }
2865
2866 return true;
2867 } // end rewrite_cp_refs_in_type_annotation_struct()
2868
2869
2870 // Read, verify and skip over the target_type and target_info part
2871 // so that rewriting can continue in the later parts of the struct.
2872 //
2873 // u1 target_type;
2874 // union {
2875 // type_parameter_target;
2876 // supertype_target;
2877 // type_parameter_bound_target;
2878 // empty_target;
2879 // method_formal_parameter_target;
2880 // throws_target;
2881 // localvar_target;
2882 // catch_target;
2883 // offset_target;
2884 // type_argument_target;
2885 // } target_info;
2886 //
2887 bool VM_RedefineClasses::skip_type_annotation_target(
2888 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2889 const char * location_mesg) {
2890
2891 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2892 // not enough room for a target_type let alone the rest of a type_annotation
2893 log_debug(redefine, class, annotation)("length() is too small for a target_type");
2894 return false;
2895 }
2896
2897 u1 target_type = type_annotations_typeArray->at(byte_i_ref);
2898 byte_i_ref += 1;
2899 log_debug(redefine, class, annotation)("target_type=0x%.2x", target_type);
2900 log_debug(redefine, class, annotation)("location=%s", location_mesg);
2901
2902 // Skip over target_info
2903 switch (target_type) {
2904 case 0x00:
2905 // kind: type parameter declaration of generic class or interface
2906 // location: ClassFile
2907 case 0x01:
2908 // kind: type parameter declaration of generic method or constructor
2909 // location: method_info
2910
2911 {
2912 // struct:
2913 // type_parameter_target {
2914 // u1 type_parameter_index;
2915 // }
2916 //
2917 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2918 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_target");
2919 return false;
2920 }
2921
2922 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2923 byte_i_ref += 1;
2924
2925 log_debug(redefine, class, annotation)("type_parameter_target: type_parameter_index=%d", type_parameter_index);
2926 } break;
2927
2928 case 0x10:
2929 // kind: type in extends clause of class or interface declaration
2930 // or in implements clause of interface declaration
2931 // location: ClassFile
2932
2933 {
2934 // struct:
2935 // supertype_target {
2936 // u2 supertype_index;
2937 // }
2938 //
2939 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2940 log_debug(redefine, class, annotation)("length() is too small for a supertype_target");
2941 return false;
2942 }
2943
2944 u2 supertype_index = Bytes::get_Java_u2((address)
2945 type_annotations_typeArray->adr_at(byte_i_ref));
2946 byte_i_ref += 2;
2947
2948 log_debug(redefine, class, annotation)("supertype_target: supertype_index=%d", supertype_index);
2949 } break;
2950
2951 case 0x11:
2952 // kind: type in bound of type parameter declaration of generic class or interface
2953 // location: ClassFile
2954 case 0x12:
2955 // kind: type in bound of type parameter declaration of generic method or constructor
2956 // location: method_info
2957
2958 {
2959 // struct:
2960 // type_parameter_bound_target {
2961 // u1 type_parameter_index;
2962 // u1 bound_index;
2963 // }
2964 //
2965 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2966 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_bound_target");
2967 return false;
2968 }
2969
2970 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2971 byte_i_ref += 1;
2972 u1 bound_index = type_annotations_typeArray->at(byte_i_ref);
2973 byte_i_ref += 1;
2974
2975 log_debug(redefine, class, annotation)
2976 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d", type_parameter_index, bound_index);
2977 } break;
2978
2979 case 0x13:
2980 // kind: type in field declaration
2981 // location: field_info
2982 case 0x14:
2983 // kind: return type of method, or type of newly constructed object
2984 // location: method_info
2985 case 0x15:
2986 // kind: receiver type of method or constructor
2987 // location: method_info
2988
2989 {
2990 // struct:
2991 // empty_target {
2992 // }
2993 //
2994 log_debug(redefine, class, annotation)("empty_target");
2995 } break;
2996
2997 case 0x16:
2998 // kind: type in formal parameter declaration of method, constructor, or lambda expression
2999 // location: method_info
3000
3001 {
3002 // struct:
3003 // formal_parameter_target {
3004 // u1 formal_parameter_index;
3005 // }
3006 //
3007 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
3008 log_debug(redefine, class, annotation)("length() is too small for a formal_parameter_target");
3009 return false;
3010 }
3011
3012 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref);
3013 byte_i_ref += 1;
3014
3015 log_debug(redefine, class, annotation)
3016 ("formal_parameter_target: formal_parameter_index=%d", formal_parameter_index);
3017 } break;
3018
3019 case 0x17:
3020 // kind: type in throws clause of method or constructor
3021 // location: method_info
3022
3023 {
3024 // struct:
3025 // throws_target {
3026 // u2 throws_type_index
3027 // }
3028 //
3029 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
3030 log_debug(redefine, class, annotation)("length() is too small for a throws_target");
3031 return false;
3032 }
3033
3034 u2 throws_type_index = Bytes::get_Java_u2((address)
3035 type_annotations_typeArray->adr_at(byte_i_ref));
3036 byte_i_ref += 2;
3037
3038 log_debug(redefine, class, annotation)("throws_target: throws_type_index=%d", throws_type_index);
3039 } break;
3040
3041 case 0x40:
3042 // kind: type in local variable declaration
3043 // location: Code
3044 case 0x41:
3045 // kind: type in resource variable declaration
3046 // location: Code
3047
3048 {
3049 // struct:
3050 // localvar_target {
3051 // u2 table_length;
3052 // struct {
3053 // u2 start_pc;
3054 // u2 length;
3055 // u2 index;
3056 // } table[table_length];
3057 // }
3058 //
3059 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
3060 // not enough room for a table_length let alone the rest of a localvar_target
3061 log_debug(redefine, class, annotation)("length() is too small for a localvar_target table_length");
3062 return false;
3063 }
3064
3065 u2 table_length = Bytes::get_Java_u2((address)
3066 type_annotations_typeArray->adr_at(byte_i_ref));
3067 byte_i_ref += 2;
3068
3069 log_debug(redefine, class, annotation)("localvar_target: table_length=%d", table_length);
3070
3071 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry
3072 int table_size = table_length * table_struct_size;
3073
3074 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) {
3075 // not enough room for a table
3076 log_debug(redefine, class, annotation)("length() is too small for a table array of length %d", table_length);
3077 return false;
3078 }
3079
3080 // Skip over table
3081 byte_i_ref += table_size;
3082 } break;
3083
3084 case 0x42:
3085 // kind: type in exception parameter declaration
3086 // location: Code
3087
3088 {
3089 // struct:
3090 // catch_target {
3091 // u2 exception_table_index;
3092 // }
3093 //
3094 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
3095 log_debug(redefine, class, annotation)("length() is too small for a catch_target");
3096 return false;
3097 }
3098
3099 u2 exception_table_index = Bytes::get_Java_u2((address)
3100 type_annotations_typeArray->adr_at(byte_i_ref));
3101 byte_i_ref += 2;
3102
3103 log_debug(redefine, class, annotation)("catch_target: exception_table_index=%d", exception_table_index);
3104 } break;
3105
3106 case 0x43:
3107 // kind: type in instanceof expression
3108 // location: Code
3109 case 0x44:
3110 // kind: type in new expression
3111 // location: Code
3112 case 0x45:
3113 // kind: type in method reference expression using ::new
3114 // location: Code
3115 case 0x46:
3116 // kind: type in method reference expression using ::Identifier
3117 // location: Code
3118
3119 {
3120 // struct:
3121 // offset_target {
3122 // u2 offset;
3123 // }
3124 //
3125 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
3126 log_debug(redefine, class, annotation)("length() is too small for a offset_target");
3127 return false;
3128 }
3129
3130 u2 offset = Bytes::get_Java_u2((address)
3131 type_annotations_typeArray->adr_at(byte_i_ref));
3132 byte_i_ref += 2;
3133
3134 log_debug(redefine, class, annotation)("offset_target: offset=%d", offset);
3135 } break;
3136
3137 case 0x47:
3138 // kind: type in cast expression
3139 // location: Code
3140 case 0x48:
3141 // kind: type argument for generic constructor in new expression or
3142 // explicit constructor invocation statement
3143 // location: Code
3144 case 0x49:
3145 // kind: type argument for generic method in method invocation expression
3146 // location: Code
3147 case 0x4A:
3148 // kind: type argument for generic constructor in method reference expression using ::new
3149 // location: Code
3150 case 0x4B:
3151 // kind: type argument for generic method in method reference expression using ::Identifier
3152 // location: Code
3153
3154 {
3155 // struct:
3156 // type_argument_target {
3157 // u2 offset;
3158 // u1 type_argument_index;
3159 // }
3160 //
3161 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) {
3162 log_debug(redefine, class, annotation)("length() is too small for a type_argument_target");
3163 return false;
3164 }
3165
3166 u2 offset = Bytes::get_Java_u2((address)
3167 type_annotations_typeArray->adr_at(byte_i_ref));
3168 byte_i_ref += 2;
3169 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
3170 byte_i_ref += 1;
3171
3172 log_debug(redefine, class, annotation)
3173 ("type_argument_target: offset=%d, type_argument_index=%d", offset, type_argument_index);
3174 } break;
3175
3176 default:
3177 log_debug(redefine, class, annotation)("unknown target_type");
3178 #ifdef ASSERT
3179 ShouldNotReachHere();
3180 #endif
3181 return false;
3182 }
3183
3184 return true;
3185 } // end skip_type_annotation_target()
3186
3187
3188 // Read, verify and skip over the type_path part so that rewriting
3189 // can continue in the later parts of the struct.
3190 //
3191 // type_path {
3192 // u1 path_length;
3193 // {
3194 // u1 type_path_kind;
3195 // u1 type_argument_index;
3196 // } path[path_length];
3197 // }
3198 //
3199 bool VM_RedefineClasses::skip_type_annotation_type_path(
3200 AnnotationArray* type_annotations_typeArray, int &byte_i_ref) {
3201
3202 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
3203 // not enough room for a path_length let alone the rest of the type_path
3204 log_debug(redefine, class, annotation)("length() is too small for a type_path");
3205 return false;
3206 }
3207
3208 u1 path_length = type_annotations_typeArray->at(byte_i_ref);
3209 byte_i_ref += 1;
3210
3211 log_debug(redefine, class, annotation)("type_path: path_length=%d", path_length);
3212
3213 int calc_path_length = 0;
3214 for (; calc_path_length < path_length; calc_path_length++) {
3215 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) {
3216 // not enough room for a path
3217 log_debug(redefine, class, annotation)
3218 ("length() is too small for path entry %d of %d", calc_path_length, path_length);
3219 return false;
3220 }
3221
3222 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref);
3223 byte_i_ref += 1;
3224 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
3225 byte_i_ref += 1;
3226
3227 log_debug(redefine, class, annotation)
3228 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d",
3229 calc_path_length, type_path_kind, type_argument_index);
3230
3231 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) {
3232 // not enough room for a path
3233 log_debug(redefine, class, annotation)("inconsistent type_path values");
3234 return false;
3235 }
3236 }
3237 assert(path_length == calc_path_length, "sanity check");
3238
3239 return true;
3240 } // end skip_type_annotation_type_path()
3241
3242
3243 // Rewrite constant pool references in the method's stackmap table.
3244 // These "structures" are adapted from the StackMapTable_attribute that
3245 // is described in section 4.8.4 of the 6.0 version of the VM spec
3246 // (dated 2005.10.26):
3247 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
3248 //
3249 // stack_map {
3250 // u2 number_of_entries;
3251 // stack_map_frame entries[number_of_entries];
3252 // }
3253 //
3254 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table(
3255 const methodHandle& method) {
3256
3257 if (!method->has_stackmap_table()) {
3258 return;
3259 }
3260
3261 AnnotationArray* stackmap_data = method->stackmap_data();
3262 address stackmap_p = (address)stackmap_data->adr_at(0);
3263 address stackmap_end = stackmap_p + stackmap_data->length();
3264
3265 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries");
3266 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p);
3267 stackmap_p += 2;
3268
3269 log_debug(redefine, class, stackmap)("number_of_entries=%u", number_of_entries);
3270
3271 // walk through each stack_map_frame
3272 u2 calc_number_of_entries = 0;
3273 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) {
3274 // The stack_map_frame structure is a u1 frame_type followed by
3275 // 0 or more bytes of data:
3276 //
3277 // union stack_map_frame {
3278 // same_frame;
3279 // same_locals_1_stack_item_frame;
3280 // same_locals_1_stack_item_frame_extended;
3281 // chop_frame;
3282 // same_frame_extended;
3283 // append_frame;
3284 // full_frame;
3285 // }
3286
3287 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type");
3288 u1 frame_type = *stackmap_p;
3289 stackmap_p++;
3290
3291 if (frame_type == 246) { // EARLY_LARVAL
3292 // rewrite_cp_refs in unset fields and fall through.
3293 rewrite_cp_refs_in_early_larval_stackmaps(stackmap_p, stackmap_end, calc_number_of_entries, frame_type);
3294 // The larval frames point to the next frame, so advance to the next frame and fall through.
3295 frame_type = *stackmap_p;
3296 stackmap_p++;
3297 }
3298
3299 // same_frame {
3300 // u1 frame_type = SAME; /* 0-63 */
3301 // }
3302 if (frame_type <= StackMapReader::SAME_FRAME_END) {
3303 // nothing more to do for same_frame
3304 }
3305
3306 // same_locals_1_stack_item_frame {
3307 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */
3308 // verification_type_info stack[1];
3309 // }
3310 else if (frame_type >= StackMapReader::SAME_LOCALS_1_STACK_ITEM_FRAME_START &&
3311 frame_type <= StackMapReader::SAME_LOCALS_1_STACK_ITEM_FRAME_END) {
3312 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3313 calc_number_of_entries, frame_type);
3314 }
3315
3316 // reserved for future use
3317 else if (frame_type >= StackMapReader::RESERVED_START &&
3318 frame_type <= StackMapReader::RESERVED_END) {
3319 // nothing more to do for reserved frame_types
3320 }
3321
3322 // same_locals_1_stack_item_frame_extended {
3323 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */
3324 // u2 offset_delta;
3325 // verification_type_info stack[1];
3326 // }
3327 else if (frame_type == StackMapReader::SAME_LOCALS_1_STACK_ITEM_EXTENDED) {
3328 stackmap_p += 2;
3329 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3330 calc_number_of_entries, frame_type);
3331 }
3332
3333 // chop_frame {
3334 // u1 frame_type = CHOP; /* 248-250 */
3335 // u2 offset_delta;
3336 // }
3337 else if (frame_type >= StackMapReader::CHOP_FRAME_START &&
3338 frame_type <= StackMapReader::CHOP_FRAME_END) {
3339 stackmap_p += 2;
3340 }
3341
3342 // same_frame_extended {
3343 // u1 frame_type = SAME_EXTENDED; /* 251 */
3344 // u2 offset_delta;
3345 // }
3346 else if (frame_type == StackMapReader::SAME_FRAME_EXTENDED) {
3347 stackmap_p += 2;
3348 }
3349
3350 // append_frame {
3351 // u1 frame_type = APPEND; /* 252-254 */
3352 // u2 offset_delta;
3353 // verification_type_info locals[frame_type - SAME_EXTENDED];
3354 // }
3355 else if (frame_type >= StackMapReader::APPEND_FRAME_START &&
3356 frame_type <= StackMapReader::APPEND_FRAME_END) {
3357 assert(stackmap_p + 2 <= stackmap_end,
3358 "no room for offset_delta");
3359 stackmap_p += 2;
3360 u1 len = frame_type - StackMapReader::APPEND_FRAME_START + 1;
3361 for (u1 i = 0; i < len; i++) {
3362 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3363 calc_number_of_entries, frame_type);
3364 }
3365 }
3366
3367 // full_frame {
3368 // u1 frame_type = FULL_FRAME; /* 255 */
3369 // u2 offset_delta;
3370 // u2 number_of_locals;
3371 // verification_type_info locals[number_of_locals];
3372 // u2 number_of_stack_items;
3373 // verification_type_info stack[number_of_stack_items];
3374 // }
3375 else if (frame_type == StackMapReader::FULL_FRAME) {
3376 assert(stackmap_p + 2 + 2 <= stackmap_end,
3377 "no room for smallest full_frame");
3378 stackmap_p += 2;
3379
3380 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p);
3381 stackmap_p += 2;
3382
3383 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) {
3384 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3385 calc_number_of_entries, frame_type);
3386 }
3387
3388 // Use the largest size for the number_of_stack_items, but only get
3389 // the right number of bytes.
3390 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p);
3391 stackmap_p += 2;
3392
3393 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) {
3394 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3395 calc_number_of_entries, frame_type);
3396 }
3397 }
3398 } // end while there is a stack_map_frame
3399 assert(number_of_entries == calc_number_of_entries, "sanity check");
3400 } // end rewrite_cp_refs_in_stack_map_table()
3401
3402
3403 // Rewrite constant pool references in the verification type info
3404 // portion of the method's stackmap table. These "structures" are
3405 // adapted from the StackMapTable_attribute that is described in
3406 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26):
3407 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
3408 //
3409 // The verification_type_info structure is a u1 tag followed by 0 or
3410 // more bytes of data:
3411 //
3412 // union verification_type_info {
3413 // Top_variable_info;
3414 // Integer_variable_info;
3415 // Float_variable_info;
3416 // Long_variable_info;
3417 // Double_variable_info;
3418 // Null_variable_info;
3419 // UninitializedThis_variable_info;
3420 // Object_variable_info;
3421 // Uninitialized_variable_info;
3422 // }
3423 //
3424 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info(
3425 address& stackmap_p_ref, address stackmap_end, u2 frame_i,
3426 u1 frame_type) {
3427
3428 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag");
3429 u1 tag = *stackmap_p_ref;
3430 stackmap_p_ref++;
3431
3432 switch (tag) {
3433 // Top_variable_info {
3434 // u1 tag = ITEM_Top; /* 0 */
3435 // }
3436 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top
3437 case 0: // fall through
3438
3439 // Integer_variable_info {
3440 // u1 tag = ITEM_Integer; /* 1 */
3441 // }
3442 case ITEM_Integer: // fall through
3443
3444 // Float_variable_info {
3445 // u1 tag = ITEM_Float; /* 2 */
3446 // }
3447 case ITEM_Float: // fall through
3448
3449 // Double_variable_info {
3450 // u1 tag = ITEM_Double; /* 3 */
3451 // }
3452 case ITEM_Double: // fall through
3453
3454 // Long_variable_info {
3455 // u1 tag = ITEM_Long; /* 4 */
3456 // }
3457 case ITEM_Long: // fall through
3458
3459 // Null_variable_info {
3460 // u1 tag = ITEM_Null; /* 5 */
3461 // }
3462 case ITEM_Null: // fall through
3463
3464 // UninitializedThis_variable_info {
3465 // u1 tag = ITEM_UninitializedThis; /* 6 */
3466 // }
3467 case ITEM_UninitializedThis:
3468 // nothing more to do for the above tag types
3469 break;
3470
3471 // Object_variable_info {
3472 // u1 tag = ITEM_Object; /* 7 */
3473 // u2 cpool_index;
3474 // }
3475 case ITEM_Object:
3476 {
3477 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index");
3478 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref);
3479 u2 new_cp_index = find_new_index(cpool_index);
3480 if (new_cp_index != 0) {
3481 log_debug(redefine, class, stackmap)("mapped old cpool_index=%d", cpool_index);
3482 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
3483 cpool_index = new_cp_index;
3484 }
3485 stackmap_p_ref += 2;
3486
3487 log_debug(redefine, class, stackmap)
3488 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i, frame_type, cpool_index);
3489 } break;
3490
3491 // Uninitialized_variable_info {
3492 // u1 tag = ITEM_Uninitialized; /* 8 */
3493 // u2 offset;
3494 // }
3495 case ITEM_Uninitialized:
3496 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset");
3497 stackmap_p_ref += 2;
3498 break;
3499
3500 default:
3501 log_debug(redefine, class, stackmap)("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag);
3502 ShouldNotReachHere();
3503 break;
3504 } // end switch (tag)
3505 } // end rewrite_cp_refs_in_verification_type_info()
3506
3507
3508 void VM_RedefineClasses::rewrite_cp_refs_in_early_larval_stackmaps(
3509 address& stackmap_p_ref, address stackmap_end, u2 frame_i,
3510 u1 frame_type) {
3511
3512 u2 num_early_larval_stackmaps = Bytes::get_Java_u2(stackmap_p_ref);
3513 stackmap_p_ref += 2;
3514
3515 for (u2 i = 0; i < num_early_larval_stackmaps; i++) {
3516
3517 u2 name_and_ref_index = Bytes::get_Java_u2(stackmap_p_ref);
3518 u2 new_cp_index = find_new_index(name_and_ref_index);
3519 if (new_cp_index != 0) {
3520 log_debug(redefine, class, stackmap)("mapped old name_and_ref_index=%d", name_and_ref_index);
3521 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
3522 name_and_ref_index = new_cp_index;
3523 }
3524 log_debug(redefine, class, stackmap)
3525 ("frame_i=%u, frame_type=%u, name_and_ref_index=%d", frame_i, frame_type, name_and_ref_index);
3526
3527 stackmap_p_ref += 2;
3528 }
3529 } // rewrite_cp_refs_in_early_larval_stackmaps
3530
3531 // Change the constant pool associated with klass scratch_class to scratch_cp.
3532 // scratch_cp_length elements are copied from scratch_cp to a smaller constant pool
3533 // and the smaller constant pool is associated with scratch_class.
3534 void VM_RedefineClasses::set_new_constant_pool(
3535 ClassLoaderData* loader_data,
3536 InstanceKlass* scratch_class, constantPoolHandle scratch_cp,
3537 int scratch_cp_length, TRAPS) {
3538 assert(scratch_cp->length() >= scratch_cp_length, "sanity check");
3539
3540 // scratch_cp is a merged constant pool and has enough space for a
3541 // worst case merge situation. We want to associate the minimum
3542 // sized constant pool with the klass to save space.
3543 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK);
3544 constantPoolHandle smaller_cp(THREAD, cp);
3545
3546 // preserve version() value in the smaller copy
3547 int version = scratch_cp->version();
3548 assert(version != 0, "sanity check");
3549 smaller_cp->set_version(version);
3550
3551 // attach klass to new constant pool
3552 // reference to the cp holder is needed for copy_operands()
3553 smaller_cp->set_pool_holder(scratch_class);
3554
3555 smaller_cp->copy_fields(scratch_cp());
3556
3557 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
3558 if (HAS_PENDING_EXCEPTION) {
3559 // Exception is handled in the caller
3560 loader_data->add_to_deallocate_list(smaller_cp());
3561 return;
3562 }
3563 scratch_cp = smaller_cp;
3564
3565 // attach new constant pool to klass
3566 scratch_class->set_constants(scratch_cp());
3567 scratch_cp->initialize_unresolved_klasses(loader_data, CHECK);
3568
3569 int i; // for portability
3570
3571 // update each field in klass to use new constant pool indices as needed
3572 int java_fields;
3573 int injected_fields;
3574 bool update_required = false;
3575 GrowableArray<FieldInfo>* fields = FieldInfoStream::create_FieldInfoArray(scratch_class->fieldinfo_stream(), &java_fields, &injected_fields);
3576 for (int i = 0; i < java_fields; i++) {
3577 FieldInfo* fi = fields->adr_at(i);
3578 jshort cur_index = fi->name_index();
3579 jshort new_index = find_new_index(cur_index);
3580 if (new_index != 0) {
3581 log_trace(redefine, class, constantpool)("field-name_index change: %d to %d", cur_index, new_index);
3582 fi->set_name_index(new_index);
3583 update_required = true;
3584 }
3585 cur_index = fi->signature_index();
3586 new_index = find_new_index(cur_index);
3587 if (new_index != 0) {
3588 log_trace(redefine, class, constantpool)("field-signature_index change: %d to %d", cur_index, new_index);
3589 fi->set_signature_index(new_index);
3590 update_required = true;
3591 }
3592 cur_index = fi->initializer_index();
3593 new_index = find_new_index(cur_index);
3594 if (new_index != 0) {
3595 log_trace(redefine, class, constantpool)("field-initval_index change: %d to %d", cur_index, new_index);
3596 fi->set_initializer_index(new_index);
3597 update_required = true;
3598 }
3599 cur_index = fi->generic_signature_index();
3600 new_index = find_new_index(cur_index);
3601 if (new_index != 0) {
3602 log_trace(redefine, class, constantpool)("field-generic_signature change: %d to %d", cur_index, new_index);
3603 fi->set_generic_signature_index(new_index);
3604 update_required = true;
3605 }
3606 }
3607 if (update_required) {
3608 Array<u1>* old_stream = scratch_class->fieldinfo_stream();
3609 assert(fields->length() == (java_fields + injected_fields), "Must be");
3610 Array<u1>* new_fis = FieldInfoStream::create_FieldInfoStream(fields, java_fields, injected_fields, scratch_class->class_loader_data(), CHECK);
3611 scratch_class->set_fieldinfo_stream(new_fis);
3612 MetadataFactory::free_array<u1>(scratch_class->class_loader_data(), old_stream);
3613
3614 Array<u1>* old_table = scratch_class->fieldinfo_search_table();
3615 Array<u1>* search_table = FieldInfoStream::create_search_table(scratch_class->constants(), new_fis, scratch_class->class_loader_data(), CHECK);
3616 scratch_class->set_fieldinfo_search_table(search_table);
3617 MetadataFactory::free_array<u1>(scratch_class->class_loader_data(), old_table);
3618
3619 DEBUG_ONLY(FieldInfoStream::validate_search_table(scratch_class->constants(), new_fis, search_table));
3620 }
3621
3622 // Update constant pool indices in the inner classes info to use
3623 // new constant indices as needed. The inner classes info is a
3624 // quadruple:
3625 // (inner_class_info, outer_class_info, inner_name, inner_access_flags)
3626 InnerClassesIterator iter(scratch_class);
3627 for (; !iter.done(); iter.next()) {
3628 int cur_index = iter.inner_class_info_index();
3629 if (cur_index == 0) {
3630 continue; // JVM spec. allows null inner class refs so skip it
3631 }
3632 u2 new_index = find_new_index(cur_index);
3633 if (new_index != 0) {
3634 log_trace(redefine, class, constantpool)("inner_class_info change: %d to %d", cur_index, new_index);
3635 iter.set_inner_class_info_index(new_index);
3636 }
3637 cur_index = iter.outer_class_info_index();
3638 new_index = find_new_index(cur_index);
3639 if (new_index != 0) {
3640 log_trace(redefine, class, constantpool)("outer_class_info change: %d to %d", cur_index, new_index);
3641 iter.set_outer_class_info_index(new_index);
3642 }
3643 cur_index = iter.inner_name_index();
3644 new_index = find_new_index(cur_index);
3645 if (new_index != 0) {
3646 log_trace(redefine, class, constantpool)("inner_name change: %d to %d", cur_index, new_index);
3647 iter.set_inner_name_index(new_index);
3648 }
3649 } // end for each inner class
3650
3651 // Attach each method in klass to the new constant pool and update
3652 // to use new constant pool indices as needed:
3653 Array<Method*>* methods = scratch_class->methods();
3654 for (i = methods->length() - 1; i >= 0; i--) {
3655 methodHandle method(THREAD, methods->at(i));
3656 method->set_constants(scratch_cp());
3657
3658 u2 new_index = find_new_index(method->name_index());
3659 if (new_index != 0) {
3660 log_trace(redefine, class, constantpool)
3661 ("method-name_index change: %d to %d", method->name_index(), new_index);
3662 method->set_name_index(new_index);
3663 }
3664 new_index = find_new_index(method->signature_index());
3665 if (new_index != 0) {
3666 log_trace(redefine, class, constantpool)
3667 ("method-signature_index change: %d to %d", method->signature_index(), new_index);
3668 method->set_signature_index(new_index);
3669 }
3670 new_index = find_new_index(method->generic_signature_index());
3671 if (new_index != 0) {
3672 log_trace(redefine, class, constantpool)
3673 ("method-generic_signature_index change: %d to %d", method->generic_signature_index(), new_index);
3674 method->constMethod()->set_generic_signature_index(new_index);
3675 }
3676
3677 // Update constant pool indices in the method's checked exception
3678 // table to use new constant indices as needed.
3679 int cext_length = method->checked_exceptions_length();
3680 if (cext_length > 0) {
3681 CheckedExceptionElement * cext_table =
3682 method->checked_exceptions_start();
3683 for (int j = 0; j < cext_length; j++) {
3684 int cur_index = cext_table[j].class_cp_index;
3685 int new_index = find_new_index(cur_index);
3686 if (new_index != 0) {
3687 log_trace(redefine, class, constantpool)("cext-class_cp_index change: %d to %d", cur_index, new_index);
3688 cext_table[j].class_cp_index = (u2)new_index;
3689 }
3690 } // end for each checked exception table entry
3691 } // end if there are checked exception table entries
3692
3693 // Update each catch type index in the method's exception table
3694 // to use new constant pool indices as needed. The exception table
3695 // holds quadruple entries of the form:
3696 // (beg_bci, end_bci, handler_bci, klass_index)
3697
3698 ExceptionTable ex_table(method());
3699 int ext_length = ex_table.length();
3700
3701 for (int j = 0; j < ext_length; j ++) {
3702 int cur_index = ex_table.catch_type_index(j);
3703 u2 new_index = find_new_index(cur_index);
3704 if (new_index != 0) {
3705 log_trace(redefine, class, constantpool)("ext-klass_index change: %d to %d", cur_index, new_index);
3706 ex_table.set_catch_type_index(j, new_index);
3707 }
3708 } // end for each exception table entry
3709
3710 // Update constant pool indices in the method's local variable
3711 // table to use new constant indices as needed. The local variable
3712 // table hold sextuple entries of the form:
3713 // (start_pc, length, name_index, descriptor_index, signature_index, slot)
3714 int lvt_length = method->localvariable_table_length();
3715 if (lvt_length > 0) {
3716 LocalVariableTableElement * lv_table =
3717 method->localvariable_table_start();
3718 for (int j = 0; j < lvt_length; j++) {
3719 int cur_index = lv_table[j].name_cp_index;
3720 int new_index = find_new_index(cur_index);
3721 if (new_index != 0) {
3722 log_trace(redefine, class, constantpool)("lvt-name_cp_index change: %d to %d", cur_index, new_index);
3723 lv_table[j].name_cp_index = (u2)new_index;
3724 }
3725 cur_index = lv_table[j].descriptor_cp_index;
3726 new_index = find_new_index(cur_index);
3727 if (new_index != 0) {
3728 log_trace(redefine, class, constantpool)("lvt-descriptor_cp_index change: %d to %d", cur_index, new_index);
3729 lv_table[j].descriptor_cp_index = (u2)new_index;
3730 }
3731 cur_index = lv_table[j].signature_cp_index;
3732 new_index = find_new_index(cur_index);
3733 if (new_index != 0) {
3734 log_trace(redefine, class, constantpool)("lvt-signature_cp_index change: %d to %d", cur_index, new_index);
3735 lv_table[j].signature_cp_index = (u2)new_index;
3736 }
3737 } // end for each local variable table entry
3738 } // end if there are local variable table entries
3739
3740 // Update constant pool indices in the method's method_parameters.
3741 int mp_length = method->method_parameters_length();
3742 if (mp_length > 0) {
3743 MethodParametersElement* elem = method->method_parameters_start();
3744 for (int j = 0; j < mp_length; j++) {
3745 const int cp_index = elem[j].name_cp_index;
3746 const int new_cp_index = find_new_index(cp_index);
3747 if (new_cp_index != 0) {
3748 elem[j].name_cp_index = (u2)new_cp_index;
3749 }
3750 }
3751 }
3752
3753 rewrite_cp_refs_in_stack_map_table(method);
3754 } // end for each method
3755 } // end set_new_constant_pool()
3756
3757
3758 // Unevolving classes may point to methods of the_class directly
3759 // from their constant pool caches, itables, and/or vtables. We
3760 // use the ClassLoaderDataGraph::classes_do() facility and this helper
3761 // to fix up these pointers. MethodData also points to old methods and
3762 // must be cleaned.
3763
3764 // Adjust cpools and vtables closure
3765 void VM_RedefineClasses::AdjustAndCleanMetadata::do_klass(Klass* k) {
3766
3767 // This is a very busy routine. We don't want too much tracing
3768 // printed out.
3769 bool trace_name_printed = false;
3770
3771 // If the class being redefined is java.lang.Object, we need to fix all
3772 // array class vtables also. The _has_redefined_Object flag is global.
3773 // Once the java.lang.Object has been redefined (by the current or one
3774 // of the previous VM_RedefineClasses operations) we have to always
3775 // adjust method entries for array classes.
3776 if (k->is_array_klass() && _has_redefined_Object) {
3777 k->vtable().adjust_method_entries(&trace_name_printed);
3778
3779 } else if (k->is_instance_klass()) {
3780 HandleMark hm(_thread);
3781 InstanceKlass *ik = InstanceKlass::cast(k);
3782
3783 // Clean MethodData of this class's methods so they don't refer to
3784 // old methods that are no longer running.
3785 Array<Method*>* methods = ik->methods();
3786 int num_methods = methods->length();
3787 for (int index = 0; index < num_methods; ++index) {
3788 if (methods->at(index)->method_data() != nullptr) {
3789 methods->at(index)->method_data()->clean_weak_method_links();
3790 }
3791 }
3792
3793 // Adjust all vtables, default methods and itables, to clean out old methods.
3794 ResourceMark rm(_thread);
3795 if (ik->vtable_length() > 0) {
3796 ik->vtable().adjust_method_entries(&trace_name_printed);
3797 ik->adjust_default_methods(&trace_name_printed);
3798 }
3799
3800 if (ik->itable_length() > 0) {
3801 ik->itable().adjust_method_entries(&trace_name_printed);
3802 }
3803
3804 // The constant pools in other classes (other_cp) can refer to
3805 // old methods. We have to update method information in
3806 // other_cp's cache. If other_cp has a previous version, then we
3807 // have to repeat the process for each previous version. The
3808 // constant pool cache holds the Method*s for non-virtual
3809 // methods and for virtual, final methods.
3810 //
3811 // Special case: if the current class is being redefined by the current
3812 // VM_RedefineClasses operation, then new_cp has already been attached
3813 // to the_class and old_cp has already been added as a previous version.
3814 // The new_cp doesn't have any cached references to old methods so it
3815 // doesn't need to be updated and we could optimize by skipping it.
3816 // However, the current class can be marked as being redefined by another
3817 // VM_RedefineClasses operation which has already executed its doit_prologue
3818 // and needs cpcache method entries adjusted. For simplicity, the cpcache
3819 // update is done unconditionally. It should result in doing nothing for
3820 // classes being redefined by the current VM_RedefineClasses operation.
3821 // Method entries in the previous version(s) are adjusted as well.
3822 ConstantPoolCache* cp_cache;
3823
3824 // this klass' constant pool cache may need adjustment
3825 ConstantPool* other_cp = ik->constants();
3826 cp_cache = other_cp->cache();
3827 if (cp_cache != nullptr) {
3828 cp_cache->adjust_method_entries(&trace_name_printed);
3829 }
3830
3831 // the previous versions' constant pool caches may need adjustment
3832 for (InstanceKlass* pv_node = ik->previous_versions();
3833 pv_node != nullptr;
3834 pv_node = pv_node->previous_versions()) {
3835 cp_cache = pv_node->constants()->cache();
3836 if (cp_cache != nullptr) {
3837 cp_cache->adjust_method_entries(&trace_name_printed);
3838 }
3839 }
3840 }
3841 }
3842
3843 void VM_RedefineClasses::update_jmethod_ids() {
3844 for (int j = 0; j < _matching_methods_length; ++j) {
3845 Method* old_method = _matching_old_methods[j];
3846 // The method_idnum should be within the range of 1..number-of-methods
3847 // until incremented later for obsolete methods.
3848 // The increment is so if a jmethodID is created for an old obsolete method
3849 // it gets a new jmethodID cache slot in the InstanceKlass.
3850 // They're cleaned out later when all methods of the previous version are purged.
3851 assert(old_method->method_idnum() <= _old_methods->length(),
3852 "shouldn't be incremented yet for obsolete methods");
3853 jmethodID jmid = old_method->find_jmethod_id_or_null();
3854 if (jmid != nullptr) {
3855 // There is a jmethodID, change it to point to the new method
3856 Method* new_method = _matching_new_methods[j];
3857 Method::change_method_associated_with_jmethod_id(jmid, new_method);
3858 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j],
3859 "should be replaced");
3860 }
3861 }
3862 }
3863
3864 int VM_RedefineClasses::check_methods_and_mark_as_obsolete() {
3865 int emcp_method_count = 0;
3866 int obsolete_count = 0;
3867 int old_index = 0;
3868 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
3869 Method* old_method = _matching_old_methods[j];
3870 Method* new_method = _matching_new_methods[j];
3871 Method* old_array_method;
3872
3873 // Maintain an old_index into the _old_methods array by skipping
3874 // deleted methods
3875 while ((old_array_method = _old_methods->at(old_index)) != old_method) {
3876 ++old_index;
3877 }
3878
3879 if (MethodComparator::methods_EMCP(old_method, new_method)) {
3880 // The EMCP definition from JSR-163 requires the bytecodes to be
3881 // the same with the exception of constant pool indices which may
3882 // differ. However, the constants referred to by those indices
3883 // must be the same.
3884 //
3885 // We use methods_EMCP() for comparison since constant pool
3886 // merging can remove duplicate constant pool entries that were
3887 // present in the old method and removed from the rewritten new
3888 // method. A faster binary comparison function would consider the
3889 // old and new methods to be different when they are actually
3890 // EMCP.
3891 //
3892 // The old and new methods are EMCP and you would think that we
3893 // could get rid of one of them here and now and save some space.
3894 // However, the concept of EMCP only considers the bytecodes and
3895 // the constant pool entries in the comparison. Other things,
3896 // e.g., the line number table (LNT) or the local variable table
3897 // (LVT) don't count in the comparison. So the new (and EMCP)
3898 // method can have a new LNT that we need so we can't just
3899 // overwrite the new method with the old method.
3900 //
3901 // When this routine is called, we have already attached the new
3902 // methods to the_class so the old methods are effectively
3903 // overwritten. However, if an old method is still executing,
3904 // then the old method cannot be collected until sometime after
3905 // the old method call has returned. So the overwriting of old
3906 // methods by new methods will save us space except for those
3907 // (hopefully few) old methods that are still executing.
3908 //
3909 // A method refers to a ConstMethod* and this presents another
3910 // possible avenue to space savings. The ConstMethod* in the
3911 // new method contains possibly new attributes (LNT, LVT, etc).
3912 // At first glance, it seems possible to save space by replacing
3913 // the ConstMethod* in the old method with the ConstMethod*
3914 // from the new method. The old and new methods would share the
3915 // same ConstMethod* and we would save the space occupied by
3916 // the old ConstMethod*. However, the ConstMethod* contains
3917 // a back reference to the containing method. Sharing the
3918 // ConstMethod* between two methods could lead to confusion in
3919 // the code that uses the back reference. This would lead to
3920 // brittle code that could be broken in non-obvious ways now or
3921 // in the future.
3922 //
3923 // Another possibility is to copy the ConstMethod* from the new
3924 // method to the old method and then overwrite the new method with
3925 // the old method. Since the ConstMethod* contains the bytecodes
3926 // for the method embedded in the oop, this option would change
3927 // the bytecodes out from under any threads executing the old
3928 // method and make the thread's bcp invalid. Since EMCP requires
3929 // that the bytecodes be the same modulo constant pool indices, it
3930 // is straight forward to compute the correct new bcp in the new
3931 // ConstMethod* from the old bcp in the old ConstMethod*. The
3932 // time consuming part would be searching all the frames in all
3933 // of the threads to find all of the calls to the old method.
3934 //
3935 // It looks like we will have to live with the limited savings
3936 // that we get from effectively overwriting the old methods
3937 // when the new methods are attached to the_class.
3938
3939 // Count number of methods that are EMCP. The method will be marked
3940 // old but not obsolete if it is EMCP.
3941 emcp_method_count++;
3942
3943 // An EMCP method is _not_ obsolete. An obsolete method has a
3944 // different jmethodID than the current method. An EMCP method
3945 // has the same jmethodID as the current method. Having the
3946 // same jmethodID for all EMCP versions of a method allows for
3947 // a consistent view of the EMCP methods regardless of which
3948 // EMCP method you happen to have in hand. For example, a
3949 // breakpoint set in one EMCP method will work for all EMCP
3950 // versions of the method including the current one.
3951 } else {
3952 // mark obsolete methods as such
3953 old_method->set_is_obsolete();
3954 obsolete_count++;
3955
3956 // obsolete methods need a unique idnum so they become new entries in
3957 // the jmethodID cache in InstanceKlass
3958 assert(old_method->method_idnum() == new_method->method_idnum(), "must match");
3959 u2 num = InstanceKlass::cast(_the_class)->next_method_idnum();
3960 if (num != ConstMethod::UNSET_IDNUM) {
3961 old_method->set_method_idnum(num);
3962 }
3963
3964 // With tracing we try not to "yack" too much. The position of
3965 // this trace assumes there are fewer obsolete methods than
3966 // EMCP methods.
3967 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) {
3968 ResourceMark rm;
3969 log_trace(redefine, class, obsolete, mark)
3970 ("mark %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string());
3971 }
3972 }
3973 old_method->set_is_old();
3974 }
3975 for (int i = 0; i < _deleted_methods_length; ++i) {
3976 Method* old_method = _deleted_methods[i];
3977
3978 assert(!old_method->has_vtable_index(),
3979 "cannot delete methods with vtable entries");;
3980
3981 // Mark all deleted methods as old, obsolete and deleted
3982 old_method->set_is_deleted();
3983 old_method->set_is_old();
3984 old_method->set_is_obsolete();
3985 ++obsolete_count;
3986 // With tracing we try not to "yack" too much. The position of
3987 // this trace assumes there are fewer obsolete methods than
3988 // EMCP methods.
3989 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) {
3990 ResourceMark rm;
3991 log_trace(redefine, class, obsolete, mark)
3992 ("mark deleted %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string());
3993 }
3994 }
3995 assert((emcp_method_count + obsolete_count) == _old_methods->length(),
3996 "sanity check");
3997 log_trace(redefine, class, obsolete, mark)("EMCP_cnt=%d, obsolete_cnt=%d", emcp_method_count, obsolete_count);
3998 return emcp_method_count;
3999 }
4000
4001 // This internal class transfers the native function registration from old methods
4002 // to new methods. It is designed to handle both the simple case of unchanged
4003 // native methods and the complex cases of native method prefixes being added and/or
4004 // removed.
4005 // It expects only to be used during the VM_RedefineClasses op (a safepoint).
4006 //
4007 // This class is used after the new methods have been installed in "the_class".
4008 //
4009 // So, for example, the following must be handled. Where 'm' is a method and
4010 // a number followed by an underscore is a prefix.
4011 //
4012 // Old Name New Name
4013 // Simple transfer to new method m -> m
4014 // Add prefix m -> 1_m
4015 // Remove prefix 1_m -> m
4016 // Simultaneous add of prefixes m -> 3_2_1_m
4017 // Simultaneous removal of prefixes 3_2_1_m -> m
4018 // Simultaneous add and remove 1_m -> 2_m
4019 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m
4020 //
4021 class TransferNativeFunctionRegistration {
4022 private:
4023 InstanceKlass* the_class;
4024 int prefix_count;
4025 char** prefixes;
4026
4027 // Recursively search the binary tree of possibly prefixed method names.
4028 // Iteration could be used if all agents were well behaved. Full tree walk is
4029 // more resilent to agents not cleaning up intermediate methods.
4030 // Branch at each depth in the binary tree is:
4031 // (1) without the prefix.
4032 // (2) with the prefix.
4033 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
4034 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len,
4035 Symbol* signature) {
4036 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len);
4037 if (name_symbol != nullptr) {
4038 Method* method = the_class->lookup_method(name_symbol, signature);
4039 if (method != nullptr) {
4040 // Even if prefixed, intermediate methods must exist.
4041 if (method->is_native()) {
4042 // Wahoo, we found a (possibly prefixed) version of the method, return it.
4043 return method;
4044 }
4045 if (depth < prefix_count) {
4046 // Try applying further prefixes (other than this one).
4047 method = search_prefix_name_space(depth+1, name_str, name_len, signature);
4048 if (method != nullptr) {
4049 return method; // found
4050 }
4051
4052 // Try adding this prefix to the method name and see if it matches
4053 // another method name.
4054 char* prefix = prefixes[depth];
4055 size_t prefix_len = strlen(prefix);
4056 size_t trial_len = name_len + prefix_len;
4057 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
4058 strcpy(trial_name_str, prefix);
4059 strcat(trial_name_str, name_str);
4060 method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
4061 signature);
4062 if (method != nullptr) {
4063 // If found along this branch, it was prefixed, mark as such
4064 method->set_is_prefixed_native();
4065 return method; // found
4066 }
4067 }
4068 }
4069 }
4070 return nullptr; // This whole branch bore nothing
4071 }
4072
4073 // Return the method name with old prefixes stripped away.
4074 char* method_name_without_prefixes(Method* method) {
4075 Symbol* name = method->name();
4076 char* name_str = name->as_utf8();
4077
4078 // Old prefixing may be defunct, strip prefixes, if any.
4079 for (int i = prefix_count-1; i >= 0; i--) {
4080 char* prefix = prefixes[i];
4081 size_t prefix_len = strlen(prefix);
4082 if (strncmp(prefix, name_str, prefix_len) == 0) {
4083 name_str += prefix_len;
4084 }
4085 }
4086 return name_str;
4087 }
4088
4089 // Strip any prefixes off the old native method, then try to find a
4090 // (possibly prefixed) new native that matches it.
4091 Method* strip_and_search_for_new_native(Method* method) {
4092 ResourceMark rm;
4093 char* name_str = method_name_without_prefixes(method);
4094 return search_prefix_name_space(0, name_str, strlen(name_str),
4095 method->signature());
4096 }
4097
4098 public:
4099
4100 // Construct a native method transfer processor for this class.
4101 TransferNativeFunctionRegistration(InstanceKlass* _the_class) {
4102 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
4103
4104 the_class = _the_class;
4105 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
4106 }
4107
4108 // Attempt to transfer any of the old or deleted methods that are native
4109 void transfer_registrations(Method** old_methods, int methods_length) {
4110 for (int j = 0; j < methods_length; j++) {
4111 Method* old_method = old_methods[j];
4112
4113 if (old_method->is_native() && old_method->has_native_function()) {
4114 Method* new_method = strip_and_search_for_new_native(old_method);
4115 if (new_method != nullptr) {
4116 // Actually set the native function in the new method.
4117 // Redefine does not send events (except CFLH), certainly not this
4118 // behind the scenes re-registration.
4119 new_method->set_native_function(old_method->native_function(),
4120 !Method::native_bind_event_is_interesting);
4121 }
4122 }
4123 }
4124 }
4125 };
4126
4127 // Don't lose the association between a native method and its JNI function.
4128 void VM_RedefineClasses::transfer_old_native_function_registrations(InstanceKlass* the_class) {
4129 TransferNativeFunctionRegistration transfer(the_class);
4130 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length);
4131 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length);
4132 }
4133
4134 // Deoptimize all compiled code that depends on the classes redefined.
4135 //
4136 // If the can_redefine_classes capability is obtained in the onload
4137 // phase or 'AlwaysRecordEvolDependencies' is true, then the compiler has
4138 // recorded all dependencies from startup. In that case we need only
4139 // deoptimize and throw away all compiled code that depends on the class.
4140 //
4141 // If can_redefine_classes is obtained sometime after the onload phase
4142 // (and 'AlwaysRecordEvolDependencies' is false) then the dependency
4143 // information may be incomplete. In that case the first call to
4144 // RedefineClasses causes all compiled code to be thrown away. As
4145 // can_redefine_classes has been obtained then all future compilations will
4146 // record dependencies so second and subsequent calls to RedefineClasses
4147 // need only throw away code that depends on the class.
4148 //
4149
4150 void VM_RedefineClasses::flush_dependent_code() {
4151 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
4152 assert(JvmtiExport::all_dependencies_are_recorded() || !AlwaysRecordEvolDependencies, "sanity check");
4153
4154 DeoptimizationScope deopt_scope;
4155
4156 // This is the first redefinition, mark all the nmethods for deoptimization
4157 if (!JvmtiExport::all_dependencies_are_recorded()) {
4158 CodeCache::mark_all_nmethods_for_evol_deoptimization(&deopt_scope);
4159 log_debug(redefine, class, nmethod)("Marked all nmethods for deopt");
4160 } else {
4161 CodeCache::mark_dependents_for_evol_deoptimization(&deopt_scope);
4162 log_debug(redefine, class, nmethod)("Marked dependent nmethods for deopt");
4163 }
4164
4165 deopt_scope.deoptimize_marked();
4166
4167 // From now on we know that the dependency information is complete
4168 JvmtiExport::set_all_dependencies_are_recorded(true);
4169 }
4170
4171 void VM_RedefineClasses::compute_added_deleted_matching_methods() {
4172 Method* old_method;
4173 Method* new_method;
4174
4175 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
4176 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
4177 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length());
4178 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
4179
4180 _matching_methods_length = 0;
4181 _deleted_methods_length = 0;
4182 _added_methods_length = 0;
4183
4184 int nj = 0;
4185 int oj = 0;
4186 while (true) {
4187 if (oj >= _old_methods->length()) {
4188 if (nj >= _new_methods->length()) {
4189 break; // we've looked at everything, done
4190 }
4191 // New method at the end
4192 new_method = _new_methods->at(nj);
4193 _added_methods[_added_methods_length++] = new_method;
4194 ++nj;
4195 } else if (nj >= _new_methods->length()) {
4196 // Old method, at the end, is deleted
4197 old_method = _old_methods->at(oj);
4198 _deleted_methods[_deleted_methods_length++] = old_method;
4199 ++oj;
4200 } else {
4201 old_method = _old_methods->at(oj);
4202 new_method = _new_methods->at(nj);
4203 if (old_method->name() == new_method->name()) {
4204 if (old_method->signature() == new_method->signature()) {
4205 _matching_old_methods[_matching_methods_length ] = old_method;
4206 _matching_new_methods[_matching_methods_length++] = new_method;
4207 ++nj;
4208 ++oj;
4209 } else {
4210 // added overloaded have already been moved to the end,
4211 // so this is a deleted overloaded method
4212 _deleted_methods[_deleted_methods_length++] = old_method;
4213 ++oj;
4214 }
4215 } else { // names don't match
4216 if (old_method->name()->fast_compare(new_method->name()) > 0) {
4217 // new method
4218 _added_methods[_added_methods_length++] = new_method;
4219 ++nj;
4220 } else {
4221 // deleted method
4222 _deleted_methods[_deleted_methods_length++] = old_method;
4223 ++oj;
4224 }
4225 }
4226 }
4227 }
4228 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
4229 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
4230 }
4231
4232
4233 void VM_RedefineClasses::swap_annotations(InstanceKlass* the_class,
4234 InstanceKlass* scratch_class) {
4235 // Swap annotation fields values
4236 Annotations* old_annotations = the_class->annotations();
4237 the_class->set_annotations(scratch_class->annotations());
4238 scratch_class->set_annotations(old_annotations);
4239 }
4240
4241
4242 // Install the redefinition of a class:
4243 // - house keeping (flushing breakpoints and caches, deoptimizing
4244 // dependent compiled code)
4245 // - replacing parts in the_class with parts from scratch_class
4246 // - adding a weak reference to track the obsolete but interesting
4247 // parts of the_class
4248 // - adjusting constant pool caches and vtables in other classes
4249 // that refer to methods in the_class. These adjustments use the
4250 // ClassLoaderDataGraph::classes_do() facility which only allows
4251 // a helper method to be specified. The interesting parameters
4252 // that we would like to pass to the helper method are saved in
4253 // static global fields in the VM operation.
4254 void VM_RedefineClasses::redefine_single_class(Thread* current, jclass the_jclass,
4255 InstanceKlass* scratch_class) {
4256
4257 HandleMark hm(current); // make sure handles from this call are freed
4258
4259 if (log_is_enabled(Info, redefine, class, timer)) {
4260 _timer_rsc_phase1.start();
4261 }
4262
4263 InstanceKlass* the_class = get_ik(the_jclass);
4264
4265 // Set a flag to control and optimize adjusting method entries
4266 _has_redefined_Object |= the_class == vmClasses::Object_klass();
4267
4268 // Remove all breakpoints in methods of this class
4269 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
4270 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class);
4271
4272 _old_methods = the_class->methods();
4273 _new_methods = scratch_class->methods();
4274 _the_class = the_class;
4275 compute_added_deleted_matching_methods();
4276 update_jmethod_ids();
4277
4278 _any_class_has_resolved_methods = the_class->has_resolved_methods() || _any_class_has_resolved_methods;
4279
4280 // Attach new constant pool to the original klass. The original
4281 // klass still refers to the old constant pool (for now).
4282 scratch_class->constants()->set_pool_holder(the_class);
4283
4284 #if 0
4285 // In theory, with constant pool merging in place we should be able
4286 // to save space by using the new, merged constant pool in place of
4287 // the old constant pool(s). By "pool(s)" I mean the constant pool in
4288 // the klass version we are replacing now and any constant pool(s) in
4289 // previous versions of klass. Nice theory, doesn't work in practice.
4290 // When this code is enabled, even simple programs throw NullPointer
4291 // exceptions. I'm guessing that this is caused by some constant pool
4292 // cache difference between the new, merged constant pool and the
4293 // constant pool that was just being used by the klass. I'm keeping
4294 // this code around to archive the idea, but the code has to remain
4295 // disabled for now.
4296
4297 // Attach each old method to the new constant pool. This can be
4298 // done here since we are past the bytecode verification and
4299 // constant pool optimization phases.
4300 for (int i = _old_methods->length() - 1; i >= 0; i--) {
4301 Method* method = _old_methods->at(i);
4302 method->set_constants(scratch_class->constants());
4303 }
4304
4305 // NOTE: this doesn't work because you can redefine the same class in two
4306 // threads, each getting their own constant pool data appended to the
4307 // original constant pool. In order for the new methods to work when they
4308 // become old methods, they need to keep their updated copy of the constant pool.
4309
4310 {
4311 // walk all previous versions of the klass
4312 InstanceKlass *ik = the_class;
4313 PreviousVersionWalker pvw(ik);
4314 do {
4315 ik = pvw.next_previous_version();
4316 if (ik != nullptr) {
4317
4318 // attach previous version of klass to the new constant pool
4319 ik->set_constants(scratch_class->constants());
4320
4321 // Attach each method in the previous version of klass to the
4322 // new constant pool
4323 Array<Method*>* prev_methods = ik->methods();
4324 for (int i = prev_methods->length() - 1; i >= 0; i--) {
4325 Method* method = prev_methods->at(i);
4326 method->set_constants(scratch_class->constants());
4327 }
4328 }
4329 } while (ik != nullptr);
4330 }
4331 #endif
4332
4333 // Replace methods and constantpool
4334 the_class->set_methods(_new_methods);
4335 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods,
4336 // and to be able to undo operation easily.
4337
4338 Array<int>* old_ordering = the_class->method_ordering();
4339 the_class->set_method_ordering(scratch_class->method_ordering());
4340 scratch_class->set_method_ordering(old_ordering);
4341
4342 ConstantPool* old_constants = the_class->constants();
4343 the_class->set_constants(scratch_class->constants());
4344 scratch_class->set_constants(old_constants); // See the previous comment.
4345 #if 0
4346 // We are swapping the guts of "the new class" with the guts of "the
4347 // class". Since the old constant pool has just been attached to "the
4348 // new class", it seems logical to set the pool holder in the old
4349 // constant pool also. However, doing this will change the observable
4350 // class hierarchy for any old methods that are still executing. A
4351 // method can query the identity of its "holder" and this query uses
4352 // the method's constant pool link to find the holder. The change in
4353 // holding class from "the class" to "the new class" can confuse
4354 // things.
4355 //
4356 // Setting the old constant pool's holder will also cause
4357 // verification done during vtable initialization below to fail.
4358 // During vtable initialization, the vtable's class is verified to be
4359 // a subtype of the method's holder. The vtable's class is "the
4360 // class" and the method's holder is gotten from the constant pool
4361 // link in the method itself. For "the class"'s directly implemented
4362 // methods, the method holder is "the class" itself (as gotten from
4363 // the new constant pool). The check works fine in this case. The
4364 // check also works fine for methods inherited from super classes.
4365 //
4366 // Miranda methods are a little more complicated. A miranda method is
4367 // provided by an interface when the class implementing the interface
4368 // does not provide its own method. These interfaces are implemented
4369 // internally as an InstanceKlass. These special instanceKlasses
4370 // share the constant pool of the class that "implements" the
4371 // interface. By sharing the constant pool, the method holder of a
4372 // miranda method is the class that "implements" the interface. In a
4373 // non-redefine situation, the subtype check works fine. However, if
4374 // the old constant pool's pool holder is modified, then the check
4375 // fails because there is no class hierarchy relationship between the
4376 // vtable's class and "the new class".
4377
4378 old_constants->set_pool_holder(scratch_class());
4379 #endif
4380
4381 // track number of methods that are EMCP for add_previous_version() call below
4382 int emcp_method_count = check_methods_and_mark_as_obsolete();
4383 transfer_old_native_function_registrations(the_class);
4384
4385 if (scratch_class->get_cached_class_file() != the_class->get_cached_class_file()) {
4386 // 1. the_class doesn't have a cache yet, scratch_class does have a cache.
4387 // 2. The same class can be present twice in the scratch classes list or there
4388 // are multiple concurrent RetransformClasses calls on different threads.
4389 // the_class and scratch_class have the same cached bytes, but different buffers.
4390 // In such cases we need to deallocate one of the buffers.
4391 // 3. RedefineClasses and the_class has cached bytes from a previous transformation.
4392 // In the case we need to use class bytes from scratch_class.
4393 if (the_class->get_cached_class_file() != nullptr) {
4394 os::free(the_class->get_cached_class_file());
4395 }
4396 the_class->set_cached_class_file(scratch_class->get_cached_class_file());
4397 }
4398
4399 // null out in scratch class to not delete twice. The class to be redefined
4400 // always owns these bytes.
4401 scratch_class->set_cached_class_file(nullptr);
4402
4403 // Replace inner_classes
4404 Array<u2>* old_inner_classes = the_class->inner_classes();
4405 the_class->set_inner_classes(scratch_class->inner_classes());
4406 scratch_class->set_inner_classes(old_inner_classes);
4407
4408 // Initialize the vtable and interface table after
4409 // methods have been rewritten
4410 // no exception should happen here since we explicitly
4411 // do not check loader constraints.
4412 // compare_and_normalize_class_versions has already checked:
4413 // - classloaders unchanged, signatures unchanged
4414 // - all instanceKlasses for redefined classes reused & contents updated
4415 the_class->vtable().initialize_vtable();
4416 the_class->itable().initialize_itable();
4417
4418 // Update jmethodID cache if present.
4419 the_class->update_methods_jmethod_cache();
4420
4421 // Copy the "source debug extension" attribute from new class version
4422 the_class->set_source_debug_extension(
4423 scratch_class->source_debug_extension(),
4424 scratch_class->source_debug_extension() == nullptr ? 0 :
4425 (int)strlen(scratch_class->source_debug_extension()));
4426
4427 // Use of javac -g could be different in the old and the new
4428 if (scratch_class->has_localvariable_table() !=
4429 the_class->has_localvariable_table()) {
4430 the_class->set_has_localvariable_table(scratch_class->has_localvariable_table());
4431 }
4432
4433 swap_annotations(the_class, scratch_class);
4434
4435 // Replace minor version number of class file
4436 u2 old_minor_version = the_class->constants()->minor_version();
4437 the_class->constants()->set_minor_version(scratch_class->constants()->minor_version());
4438 scratch_class->constants()->set_minor_version(old_minor_version);
4439
4440 // Replace major version number of class file
4441 u2 old_major_version = the_class->constants()->major_version();
4442 the_class->constants()->set_major_version(scratch_class->constants()->major_version());
4443 scratch_class->constants()->set_major_version(old_major_version);
4444
4445 // Replace CP indexes for class and name+type of enclosing method
4446 u2 old_class_idx = the_class->enclosing_method_class_index();
4447 u2 old_method_idx = the_class->enclosing_method_method_index();
4448 the_class->set_enclosing_method_indices(
4449 scratch_class->enclosing_method_class_index(),
4450 scratch_class->enclosing_method_method_index());
4451 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx);
4452
4453 if (!the_class->has_been_redefined()) {
4454 the_class->set_has_been_redefined();
4455 }
4456
4457 // Scratch class is unloaded but still needs cleaning, and skipping for CDS.
4458 scratch_class->set_is_scratch_class();
4459
4460 // keep track of previous versions of this class
4461 the_class->add_previous_version(scratch_class, emcp_method_count);
4462
4463 JFR_ONLY(Jfr::on_klass_redefinition(the_class, scratch_class);)
4464
4465 _timer_rsc_phase1.stop();
4466 if (log_is_enabled(Info, redefine, class, timer)) {
4467 _timer_rsc_phase2.start();
4468 }
4469
4470 if (the_class->oop_map_cache() != nullptr) {
4471 // Flush references to any obsolete methods from the oop map cache
4472 // so that obsolete methods are not pinned.
4473 the_class->oop_map_cache()->flush_obsolete_entries();
4474 }
4475
4476 increment_class_counter(the_class);
4477
4478 if (EventClassRedefinition::is_enabled()) {
4479 EventClassRedefinition event;
4480 event.set_classModificationCount(java_lang_Class::classRedefinedCount(the_class->java_mirror()));
4481 event.set_redefinedClass(the_class);
4482 event.set_redefinitionId(_id);
4483 event.commit();
4484 }
4485
4486 {
4487 ResourceMark rm(current);
4488 // increment the classRedefinedCount field in the_class and in any
4489 // direct and indirect subclasses of the_class
4490 size_t avail_mem = 0;
4491 // Return value ignored - defaulting to 0 on failure.
4492 (void)os::available_memory(avail_mem);
4493 log_info(redefine, class, load)
4494 ("redefined name=%s, count=%d (avail_mem=%zuK)",
4495 the_class->external_name(), java_lang_Class::classRedefinedCount(the_class->java_mirror()), avail_mem >> 10);
4496 Events::log_redefinition(current, "redefined class name=%s, count=%d",
4497 the_class->external_name(),
4498 java_lang_Class::classRedefinedCount(the_class->java_mirror()));
4499
4500 }
4501 _timer_rsc_phase2.stop();
4502
4503 } // end redefine_single_class()
4504
4505
4506 // Increment the classRedefinedCount field in the specific InstanceKlass
4507 // and in all direct and indirect subclasses.
4508 void VM_RedefineClasses::increment_class_counter(InstanceKlass* ik) {
4509 for (ClassHierarchyIterator iter(ik); !iter.done(); iter.next()) {
4510 // Only update instanceKlasses
4511 Klass* sub = iter.klass();
4512 if (sub->is_instance_klass()) {
4513 oop class_mirror = InstanceKlass::cast(sub)->java_mirror();
4514 Klass* class_oop = java_lang_Class::as_Klass(class_mirror);
4515 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
4516 java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
4517
4518 if (class_oop != _the_class) {
4519 // _the_class count is printed at end of redefine_single_class()
4520 log_debug(redefine, class, subclass)("updated count in subclass=%s to %d", ik->external_name(), new_count);
4521 }
4522 }
4523 }
4524 }
4525
4526 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) {
4527 bool no_old_methods = true; // be optimistic
4528
4529 // Both array and instance classes have vtables.
4530 // a vtable should never contain old or obsolete methods
4531 ResourceMark rm(_thread);
4532 if (k->vtable_length() > 0 &&
4533 !k->vtable().check_no_old_or_obsolete_entries()) {
4534 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4535 log_trace(redefine, class, obsolete, metadata)
4536 ("klassVtable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4537 k->signature_name());
4538 k->vtable().dump_vtable();
4539 }
4540 no_old_methods = false;
4541 }
4542
4543 if (k->is_instance_klass()) {
4544 HandleMark hm(_thread);
4545 InstanceKlass *ik = InstanceKlass::cast(k);
4546
4547 // an itable should never contain old or obsolete methods
4548 if (ik->itable_length() > 0 &&
4549 !ik->itable().check_no_old_or_obsolete_entries()) {
4550 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4551 log_trace(redefine, class, obsolete, metadata)
4552 ("klassItable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4553 ik->signature_name());
4554 ik->itable().dump_itable();
4555 }
4556 no_old_methods = false;
4557 }
4558
4559 // the constant pool cache should never contain non-deleted old or obsolete methods
4560 if (ik->constants() != nullptr &&
4561 ik->constants()->cache() != nullptr &&
4562 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) {
4563 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4564 log_trace(redefine, class, obsolete, metadata)
4565 ("cp-cache::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4566 ik->signature_name());
4567 ik->constants()->cache()->dump_cache();
4568 }
4569 no_old_methods = false;
4570 }
4571 }
4572
4573 // print and fail guarantee if old methods are found.
4574 if (!no_old_methods) {
4575 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4576 dump_methods();
4577 } else {
4578 log_trace(redefine, class)("Use the '-Xlog:redefine+class*:' option "
4579 "to see more info about the following guarantee() failure.");
4580 }
4581 guarantee(false, "OLD and/or OBSOLETE method(s) found");
4582 }
4583 }
4584
4585 u8 VM_RedefineClasses::next_id() {
4586 while (true) {
4587 u8 id = _id_counter;
4588 u8 next_id = id + 1;
4589 u8 result = Atomic::cmpxchg(&_id_counter, id, next_id);
4590 if (result == id) {
4591 return next_id;
4592 }
4593 }
4594 }
4595
4596 void VM_RedefineClasses::dump_methods() {
4597 int j;
4598 log_trace(redefine, class, dump)("_old_methods --");
4599 for (j = 0; j < _old_methods->length(); ++j) {
4600 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4601 Method* m = _old_methods->at(j);
4602 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4603 m->access_flags().print_on(&log_stream);
4604 log_stream.print(" -- ");
4605 m->print_name(&log_stream);
4606 log_stream.cr();
4607 }
4608 log_trace(redefine, class, dump)("_new_methods --");
4609 for (j = 0; j < _new_methods->length(); ++j) {
4610 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4611 Method* m = _new_methods->at(j);
4612 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4613 m->access_flags().print_on(&log_stream);
4614 log_stream.print(" -- ");
4615 m->print_name(&log_stream);
4616 log_stream.cr();
4617 }
4618 log_trace(redefine, class, dump)("_matching_methods --");
4619 for (j = 0; j < _matching_methods_length; ++j) {
4620 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4621 Method* m = _matching_old_methods[j];
4622 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4623 m->access_flags().print_on(&log_stream);
4624 log_stream.print(" -- ");
4625 m->print_name();
4626 log_stream.cr();
4627
4628 m = _matching_new_methods[j];
4629 log_stream.print(" (%5d) ", m->vtable_index());
4630 m->access_flags().print_on(&log_stream);
4631 log_stream.cr();
4632 }
4633 log_trace(redefine, class, dump)("_deleted_methods --");
4634 for (j = 0; j < _deleted_methods_length; ++j) {
4635 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4636 Method* m = _deleted_methods[j];
4637 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4638 m->access_flags().print_on(&log_stream);
4639 log_stream.print(" -- ");
4640 m->print_name(&log_stream);
4641 log_stream.cr();
4642 }
4643 log_trace(redefine, class, dump)("_added_methods --");
4644 for (j = 0; j < _added_methods_length; ++j) {
4645 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4646 Method* m = _added_methods[j];
4647 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4648 m->access_flags().print_on(&log_stream);
4649 log_stream.print(" -- ");
4650 m->print_name(&log_stream);
4651 log_stream.cr();
4652 }
4653 }
4654
4655 void VM_RedefineClasses::print_on_error(outputStream* st) const {
4656 VM_Operation::print_on_error(st);
4657 if (_the_class != nullptr) {
4658 ResourceMark rm;
4659 st->print_cr(", redefining class %s", _the_class->external_name());
4660 }
4661 }