1 /*
2 * Copyright (c) 2003, 2025, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "cds/aotMetaspace.hpp"
26 #include "cds/cdsConfig.hpp"
27 #include "classfile/classFileStream.hpp"
28 #include "classfile/classLoaderDataGraph.hpp"
29 #include "classfile/classLoadInfo.hpp"
30 #include "classfile/javaClasses.inline.hpp"
31 #include "classfile/klassFactory.hpp"
32 #include "classfile/metadataOnStackMark.hpp"
33 #include "classfile/stackMapTable.hpp"
34 #include "classfile/symbolTable.hpp"
35 #include "classfile/verifier.hpp"
36 #include "classfile/vmClasses.hpp"
37 #include "classfile/vmSymbols.hpp"
38 #include "code/codeCache.hpp"
39 #include "compiler/compileBroker.hpp"
40 #include "interpreter/oopMapCache.hpp"
41 #include "interpreter/rewriter.hpp"
42 #include "jfr/jfrEvents.hpp"
43 #include "logging/logStream.hpp"
44 #include "memory/metadataFactory.hpp"
45 #include "memory/resourceArea.hpp"
46 #include "memory/universe.hpp"
47 #include "oops/annotations.hpp"
48 #include "oops/bsmAttribute.inline.hpp"
49 #include "oops/constantPool.inline.hpp"
50 #include "oops/fieldStreams.inline.hpp"
51 #include "oops/klass.inline.hpp"
52 #include "oops/klassVtable.hpp"
53 #include "oops/method.hpp"
54 #include "oops/oop.inline.hpp"
55 #include "oops/recordComponent.hpp"
56 #include "prims/jvmtiImpl.hpp"
57 #include "prims/jvmtiRedefineClasses.hpp"
58 #include "prims/jvmtiThreadState.inline.hpp"
59 #include "prims/methodComparator.hpp"
60 #include "prims/resolvedMethodTable.hpp"
61 #include "runtime/atomicAccess.hpp"
62 #include "runtime/deoptimization.hpp"
63 #include "runtime/handles.inline.hpp"
64 #include "runtime/jniHandles.inline.hpp"
65 #include "runtime/relocator.hpp"
66 #include "runtime/safepointVerifiers.hpp"
67 #include "utilities/bitMap.inline.hpp"
68 #include "utilities/checkedCast.hpp"
69 #include "utilities/events.hpp"
70 #include "utilities/macros.hpp"
71 #if INCLUDE_JFR
72 #include "jfr/jfr.hpp"
73 #endif
74
75 Array<Method*>* VM_RedefineClasses::_old_methods = nullptr;
76 Array<Method*>* VM_RedefineClasses::_new_methods = nullptr;
77 Method** VM_RedefineClasses::_matching_old_methods = nullptr;
78 Method** VM_RedefineClasses::_matching_new_methods = nullptr;
79 Method** VM_RedefineClasses::_deleted_methods = nullptr;
80 Method** VM_RedefineClasses::_added_methods = nullptr;
81 int VM_RedefineClasses::_matching_methods_length = 0;
82 int VM_RedefineClasses::_deleted_methods_length = 0;
83 int VM_RedefineClasses::_added_methods_length = 0;
84
85 // This flag is global as the constructor does not reset it:
86 bool VM_RedefineClasses::_has_redefined_Object = false;
87 u8 VM_RedefineClasses::_id_counter = 0;
88
89 VM_RedefineClasses::VM_RedefineClasses(jint class_count,
90 const jvmtiClassDefinition *class_defs,
91 JvmtiClassLoadKind class_load_kind) {
92 _class_count = class_count;
93 _class_defs = class_defs;
94 _class_load_kind = class_load_kind;
95 _any_class_has_resolved_methods = false;
96 _res = JVMTI_ERROR_NONE;
97 _the_class = nullptr;
98 _id = next_id();
99 }
100
101 static inline InstanceKlass* get_ik(jclass def) {
102 oop mirror = JNIHandles::resolve_non_null(def);
103 return java_lang_Class::as_InstanceKlass(mirror);
104 }
105
106 // If any of the classes are being redefined, wait
107 // Parallel constant pool merging leads to indeterminate constant pools.
108 void VM_RedefineClasses::lock_classes() {
109 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
110 GrowableArray<Klass*>* redef_classes = state->get_classes_being_redefined();
111
112 MonitorLocker ml(RedefineClasses_lock);
113
114 if (redef_classes == nullptr) {
115 redef_classes = new (mtClass) GrowableArray<Klass*>(1, mtClass);
116 state->set_classes_being_redefined(redef_classes);
117 }
118
119 bool has_redefined;
120 do {
121 has_redefined = false;
122 // Go through classes each time until none are being redefined. Skip
123 // the ones that are being redefined by this thread currently. Class file
124 // load hook event may trigger new class redefine when we are redefining
125 // a class (after lock_classes()).
126 for (int i = 0; i < _class_count; i++) {
127 InstanceKlass* ik = get_ik(_class_defs[i].klass);
128 // Check if we are currently redefining the class in this thread already.
129 if (redef_classes->contains(ik)) {
130 assert(ik->is_being_redefined(), "sanity");
131 } else {
132 if (ik->is_being_redefined()) {
133 ml.wait();
134 has_redefined = true;
135 break; // for loop
136 }
137 }
138 }
139 } while (has_redefined);
140
141 for (int i = 0; i < _class_count; i++) {
142 InstanceKlass* ik = get_ik(_class_defs[i].klass);
143 redef_classes->push(ik); // Add to the _classes_being_redefined list
144 ik->set_is_being_redefined(true);
145 }
146 ml.notify_all();
147 }
148
149 void VM_RedefineClasses::unlock_classes() {
150 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
151 GrowableArray<Klass*>* redef_classes = state->get_classes_being_redefined();
152 assert(redef_classes != nullptr, "_classes_being_redefined is not allocated");
153
154 MonitorLocker ml(RedefineClasses_lock);
155
156 for (int i = _class_count - 1; i >= 0; i--) {
157 InstanceKlass* def_ik = get_ik(_class_defs[i].klass);
158 if (redef_classes->length() > 0) {
159 // Remove the class from _classes_being_redefined list
160 Klass* k = redef_classes->pop();
161 assert(def_ik == k, "unlocking wrong class");
162 }
163 assert(def_ik->is_being_redefined(),
164 "should be being redefined to get here");
165
166 // Unlock after we finish all redefines for this class within
167 // the thread. Same class can be pushed to the list multiple
168 // times (not more than once by each recursive redefinition).
169 if (!redef_classes->contains(def_ik)) {
170 def_ik->set_is_being_redefined(false);
171 }
172 }
173 ml.notify_all();
174 }
175
176 bool VM_RedefineClasses::doit_prologue() {
177 if (_class_count == 0) {
178 _res = JVMTI_ERROR_NONE;
179 return false;
180 }
181 if (_class_defs == nullptr) {
182 _res = JVMTI_ERROR_NULL_POINTER;
183 return false;
184 }
185
186 for (int i = 0; i < _class_count; i++) {
187 if (_class_defs[i].klass == nullptr) {
188 _res = JVMTI_ERROR_INVALID_CLASS;
189 return false;
190 }
191 if (_class_defs[i].class_byte_count == 0) {
192 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT;
193 return false;
194 }
195 if (_class_defs[i].class_bytes == nullptr) {
196 _res = JVMTI_ERROR_NULL_POINTER;
197 return false;
198 }
199
200 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass);
201 // classes for primitives, arrays, and hidden classes
202 // cannot be redefined.
203 if (!is_modifiable_class(mirror)) {
204 _res = JVMTI_ERROR_UNMODIFIABLE_CLASS;
205 return false;
206 }
207 }
208
209 // Start timer after all the sanity checks; not quite accurate, but
210 // better than adding a bunch of stop() calls.
211 if (log_is_enabled(Info, redefine, class, timer)) {
212 _timer_vm_op_prologue.start();
213 }
214
215 lock_classes();
216 // We first load new class versions in the prologue, because somewhere down the
217 // call chain it is required that the current thread is a Java thread.
218 _res = load_new_class_versions();
219 if (_res != JVMTI_ERROR_NONE) {
220 // free any successfully created classes, since none are redefined
221 for (int i = 0; i < _class_count; i++) {
222 if (_scratch_classes[i] != nullptr) {
223 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data();
224 // Free the memory for this class at class unloading time. Not before
225 // because CMS might think this is still live.
226 InstanceKlass* ik = get_ik(_class_defs[i].klass);
227 if (ik->get_cached_class_file() == _scratch_classes[i]->get_cached_class_file()) {
228 // Don't double-free cached_class_file copied from the original class if error.
229 _scratch_classes[i]->set_cached_class_file(nullptr);
230 }
231 cld->add_to_deallocate_list(InstanceKlass::cast(_scratch_classes[i]));
232 }
233 }
234 // Free os::malloc allocated memory in load_new_class_version.
235 os::free(_scratch_classes);
236 _timer_vm_op_prologue.stop();
237 unlock_classes();
238 return false;
239 }
240
241 _timer_vm_op_prologue.stop();
242 return true;
243 }
244
245 void VM_RedefineClasses::doit() {
246 Thread* current = Thread::current();
247
248 if (log_is_enabled(Info, redefine, class, timer)) {
249 _timer_vm_op_doit.start();
250 }
251
252 #if INCLUDE_CDS
253 if (CDSConfig::is_using_archive()) {
254 // Sharing is enabled so we remap the shared readonly space to
255 // shared readwrite, private just in case we need to redefine
256 // a shared class. We do the remap during the doit() phase of
257 // the safepoint to be safer.
258 if (!AOTMetaspace::remap_shared_readonly_as_readwrite()) {
259 log_info(redefine, class, load)("failed to remap shared readonly space to readwrite, private");
260 _res = JVMTI_ERROR_INTERNAL;
261 _timer_vm_op_doit.stop();
262 return;
263 }
264 }
265 #endif
266
267 // Mark methods seen on stack and everywhere else so old methods are not
268 // cleaned up if they're on the stack.
269 MetadataOnStackMark md_on_stack(/*walk_all_metadata*/true, /*redefinition_walk*/true);
270 HandleMark hm(current); // make sure any handles created are deleted
271 // before the stack walk again.
272
273 for (int i = 0; i < _class_count; i++) {
274 redefine_single_class(current, _class_defs[i].klass, _scratch_classes[i]);
275 }
276
277 // Flush all compiled code that depends on the classes redefined.
278 flush_dependent_code();
279
280 // Adjust constantpool caches and vtables for all classes
281 // that reference methods of the evolved classes.
282 // Have to do this after all classes are redefined and all methods that
283 // are redefined are marked as old.
284 AdjustAndCleanMetadata adjust_and_clean_metadata(current);
285 ClassLoaderDataGraph::classes_do(&adjust_and_clean_metadata);
286
287 // JSR-292 support
288 if (_any_class_has_resolved_methods) {
289 bool trace_name_printed = false;
290 ResolvedMethodTable::adjust_method_entries(&trace_name_printed);
291 }
292
293 // Increment flag indicating that some invariants are no longer true.
294 // See jvmtiExport.hpp for detailed explanation.
295 JvmtiExport::increment_redefinition_count();
296
297 // check_class() is optionally called for product bits, but is
298 // always called for non-product bits.
299 #ifdef PRODUCT
300 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
301 #endif
302 log_trace(redefine, class, obsolete, metadata)("calling check_class");
303 CheckClass check_class(current);
304 ClassLoaderDataGraph::classes_do(&check_class);
305 #ifdef PRODUCT
306 }
307 #endif
308
309 // Clean up any metadata now unreferenced while MetadataOnStackMark is set.
310 ClassLoaderDataGraph::clean_deallocate_lists(false);
311
312 _timer_vm_op_doit.stop();
313 }
314
315 void VM_RedefineClasses::doit_epilogue() {
316 unlock_classes();
317
318 // Free os::malloc allocated memory.
319 os::free(_scratch_classes);
320
321 // Reset the_class to null for error printing.
322 _the_class = nullptr;
323
324 if (log_is_enabled(Info, redefine, class, timer)) {
325 // Used to have separate timers for "doit" and "all", but the timer
326 // overhead skewed the measurements.
327 julong doit_time = _timer_vm_op_doit.milliseconds();
328 julong all_time = _timer_vm_op_prologue.milliseconds() + doit_time;
329
330 log_info(redefine, class, timer)
331 ("vm_op: all=" JULONG_FORMAT " prologue=" JULONG_FORMAT " doit=" JULONG_FORMAT,
332 all_time, (julong)_timer_vm_op_prologue.milliseconds(), doit_time);
333 log_info(redefine, class, timer)
334 ("redefine_single_class: phase1=" JULONG_FORMAT " phase2=" JULONG_FORMAT,
335 (julong)_timer_rsc_phase1.milliseconds(), (julong)_timer_rsc_phase2.milliseconds());
336 }
337 }
338
339 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) {
340 // classes for primitives cannot be redefined
341 if (java_lang_Class::is_primitive(klass_mirror)) {
342 return false;
343 }
344 Klass* k = java_lang_Class::as_Klass(klass_mirror);
345 // classes for arrays cannot be redefined
346 if (k == nullptr || !k->is_instance_klass()) {
347 return false;
348 }
349
350 // Cannot redefine or retransform a hidden class.
351 if (InstanceKlass::cast(k)->is_hidden()) {
352 return false;
353 }
354 if (InstanceKlass::cast(k) == vmClasses::Continuation_klass()) {
355 // Don't redefine Continuation class. See 8302779.
356 return false;
357 }
358 return true;
359 }
360
361 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p
362 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For
363 // direct CP entries, there is just the current entry to append. For
364 // indirect and double-indirect CP entries, there are zero or more
365 // referenced CP entries along with the current entry to append.
366 // Indirect and double-indirect CP entries are handled by recursive
367 // calls to append_entry() as needed. The referenced CP entries are
368 // always appended to *merge_cp_p before the referee CP entry. These
369 // referenced CP entries may already exist in *merge_cp_p in which case
370 // there is nothing extra to append and only the current entry is
371 // appended.
372 void VM_RedefineClasses::append_entry(const constantPoolHandle& scratch_cp,
373 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) {
374
375 // append is different depending on entry tag type
376 switch (scratch_cp->tag_at(scratch_i).value()) {
377
378 // The old verifier is implemented outside the VM. It loads classes,
379 // but does not resolve constant pool entries directly so we never
380 // see Class entries here with the old verifier. Similarly the old
381 // verifier does not like Class entries in the input constant pool.
382 // The split-verifier is implemented in the VM so it can optionally
383 // and directly resolve constant pool entries to load classes. The
384 // split-verifier can accept either Class entries or UnresolvedClass
385 // entries in the input constant pool. We revert the appended copy
386 // back to UnresolvedClass so that either verifier will be happy
387 // with the constant pool entry.
388 //
389 // this is an indirect CP entry so it needs special handling
390 case JVM_CONSTANT_Class:
391 case JVM_CONSTANT_UnresolvedClass:
392 {
393 int name_i = scratch_cp->klass_name_index_at(scratch_i);
394 int new_name_i = find_or_append_indirect_entry(scratch_cp, name_i, merge_cp_p,
395 merge_cp_length_p);
396
397 if (new_name_i != name_i) {
398 log_trace(redefine, class, constantpool)
399 ("Class entry@%d name_index change: %d to %d",
400 *merge_cp_length_p, name_i, new_name_i);
401 }
402
403 (*merge_cp_p)->temp_unresolved_klass_at_put(*merge_cp_length_p, new_name_i);
404 if (scratch_i != *merge_cp_length_p) {
405 // The new entry in *merge_cp_p is at a different index than
406 // the new entry in scratch_cp so we need to map the index values.
407 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
408 }
409 (*merge_cp_length_p)++;
410 } break;
411
412 // these are direct CP entries so they can be directly appended,
413 // but double and long take two constant pool entries
414 case JVM_CONSTANT_Double: // fall through
415 case JVM_CONSTANT_Long:
416 {
417 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p);
418
419 if (scratch_i != *merge_cp_length_p) {
420 // The new entry in *merge_cp_p is at a different index than
421 // the new entry in scratch_cp so we need to map the index values.
422 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
423 }
424 (*merge_cp_length_p) += 2;
425 } break;
426
427 // these are direct CP entries so they can be directly appended
428 case JVM_CONSTANT_Float: // fall through
429 case JVM_CONSTANT_Integer: // fall through
430 case JVM_CONSTANT_Utf8: // fall through
431
432 // This was an indirect CP entry, but it has been changed into
433 // Symbol*s so this entry can be directly appended.
434 case JVM_CONSTANT_String: // fall through
435 {
436 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p);
437
438 if (scratch_i != *merge_cp_length_p) {
439 // The new entry in *merge_cp_p is at a different index than
440 // the new entry in scratch_cp so we need to map the index values.
441 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
442 }
443 (*merge_cp_length_p)++;
444 } break;
445
446 // this is an indirect CP entry so it needs special handling
447 case JVM_CONSTANT_NameAndType:
448 {
449 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i);
450 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p,
451 merge_cp_length_p);
452
453 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i);
454 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i,
455 merge_cp_p, merge_cp_length_p);
456
457 // If the referenced entries already exist in *merge_cp_p, then
458 // both new_name_ref_i and new_signature_ref_i will both be 0.
459 // In that case, all we are appending is the current entry.
460 if (new_name_ref_i != name_ref_i) {
461 log_trace(redefine, class, constantpool)
462 ("NameAndType entry@%d name_ref_index change: %d to %d",
463 *merge_cp_length_p, name_ref_i, new_name_ref_i);
464 }
465 if (new_signature_ref_i != signature_ref_i) {
466 log_trace(redefine, class, constantpool)
467 ("NameAndType entry@%d signature_ref_index change: %d to %d",
468 *merge_cp_length_p, signature_ref_i, new_signature_ref_i);
469 }
470
471 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p,
472 new_name_ref_i, new_signature_ref_i);
473 if (scratch_i != *merge_cp_length_p) {
474 // The new entry in *merge_cp_p is at a different index than
475 // the new entry in scratch_cp so we need to map the index values.
476 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
477 }
478 (*merge_cp_length_p)++;
479 } break;
480
481 // this is a double-indirect CP entry so it needs special handling
482 case JVM_CONSTANT_Fieldref: // fall through
483 case JVM_CONSTANT_InterfaceMethodref: // fall through
484 case JVM_CONSTANT_Methodref:
485 {
486 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i);
487 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i,
488 merge_cp_p, merge_cp_length_p);
489
490 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i);
491 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i,
492 merge_cp_p, merge_cp_length_p);
493
494 const char *entry_name = nullptr;
495 switch (scratch_cp->tag_at(scratch_i).value()) {
496 case JVM_CONSTANT_Fieldref:
497 entry_name = "Fieldref";
498 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i,
499 new_name_and_type_ref_i);
500 break;
501 case JVM_CONSTANT_InterfaceMethodref:
502 entry_name = "IFMethodref";
503 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p,
504 new_klass_ref_i, new_name_and_type_ref_i);
505 break;
506 case JVM_CONSTANT_Methodref:
507 entry_name = "Methodref";
508 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i,
509 new_name_and_type_ref_i);
510 break;
511 default:
512 guarantee(false, "bad switch");
513 break;
514 }
515
516 if (klass_ref_i != new_klass_ref_i) {
517 log_trace(redefine, class, constantpool)
518 ("%s entry@%d class_index changed: %d to %d", entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i);
519 }
520 if (name_and_type_ref_i != new_name_and_type_ref_i) {
521 log_trace(redefine, class, constantpool)
522 ("%s entry@%d name_and_type_index changed: %d to %d",
523 entry_name, *merge_cp_length_p, name_and_type_ref_i, new_name_and_type_ref_i);
524 }
525
526 if (scratch_i != *merge_cp_length_p) {
527 // The new entry in *merge_cp_p is at a different index than
528 // the new entry in scratch_cp so we need to map the index values.
529 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
530 }
531 (*merge_cp_length_p)++;
532 } break;
533
534 // this is an indirect CP entry so it needs special handling
535 case JVM_CONSTANT_MethodType:
536 {
537 int ref_i = scratch_cp->method_type_index_at(scratch_i);
538 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
539 merge_cp_length_p);
540 if (new_ref_i != ref_i) {
541 log_trace(redefine, class, constantpool)
542 ("MethodType entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i);
543 }
544 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i);
545 if (scratch_i != *merge_cp_length_p) {
546 // The new entry in *merge_cp_p is at a different index than
547 // the new entry in scratch_cp so we need to map the index values.
548 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
549 }
550 (*merge_cp_length_p)++;
551 } break;
552
553 // this is an indirect CP entry so it needs special handling
554 case JVM_CONSTANT_MethodHandle:
555 {
556 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i);
557 int ref_i = scratch_cp->method_handle_index_at(scratch_i);
558 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
559 merge_cp_length_p);
560 if (new_ref_i != ref_i) {
561 log_trace(redefine, class, constantpool)
562 ("MethodHandle entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i);
563 }
564 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i);
565 if (scratch_i != *merge_cp_length_p) {
566 // The new entry in *merge_cp_p is at a different index than
567 // the new entry in scratch_cp so we need to map the index values.
568 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
569 }
570 (*merge_cp_length_p)++;
571 } break;
572
573 // this is an indirect CP entry so it needs special handling
574 case JVM_CONSTANT_Dynamic: // fall through
575 case JVM_CONSTANT_InvokeDynamic:
576 {
577 // Index of the bootstrap specifier in the BSM array
578 int old_bs_i = scratch_cp->bootstrap_methods_attribute_index(scratch_i);
579 int new_bs_i = find_or_append_bsm_entry(scratch_cp, old_bs_i, merge_cp_p,
580 merge_cp_length_p);
581 // The bootstrap method NameAndType_info index
582 int old_ref_i = scratch_cp->bootstrap_name_and_type_ref_index_at(scratch_i);
583 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
584 merge_cp_length_p);
585 if (new_bs_i != old_bs_i) {
586 log_trace(redefine, class, constantpool)
587 ("Dynamic entry@%d bootstrap_method_attr_index change: %d to %d",
588 *merge_cp_length_p, old_bs_i, new_bs_i);
589 }
590 if (new_ref_i != old_ref_i) {
591 log_trace(redefine, class, constantpool)
592 ("Dynamic entry@%d name_and_type_index change: %d to %d", *merge_cp_length_p, old_ref_i, new_ref_i);
593 }
594
595 if (scratch_cp->tag_at(scratch_i).is_dynamic_constant()) {
596 (*merge_cp_p)->dynamic_constant_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
597 } else {
598 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
599 }
600 if (scratch_i != *merge_cp_length_p) {
601 // The new entry in *merge_cp_p is at a different index than
602 // the new entry in scratch_cp so we need to map the index values.
603 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
604 }
605 (*merge_cp_length_p)++;
606 } break;
607
608 // At this stage, Class or UnresolvedClass could be in scratch_cp, but not
609 // ClassIndex
610 case JVM_CONSTANT_ClassIndex: // fall through
611
612 // Invalid is used as the tag for the second constant pool entry
613 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
614 // not be seen by itself.
615 case JVM_CONSTANT_Invalid: // fall through
616
617 // At this stage, String could be here, but not StringIndex
618 case JVM_CONSTANT_StringIndex: // fall through
619
620 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be
621 // here
622 case JVM_CONSTANT_UnresolvedClassInError: // fall through
623
624 default:
625 {
626 // leave a breadcrumb
627 jbyte bad_value = scratch_cp->tag_at(scratch_i).value();
628 ShouldNotReachHere();
629 } break;
630 } // end switch tag value
631 } // end append_entry()
632
633
634 u2 VM_RedefineClasses::find_or_append_indirect_entry(const constantPoolHandle& scratch_cp,
635 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) {
636
637 int new_ref_i = ref_i;
638 bool match = (ref_i < *merge_cp_length_p) &&
639 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i);
640
641 if (!match) {
642 // forward reference in *merge_cp_p or not a direct match
643 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p);
644 if (found_i != 0) {
645 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree");
646 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry.
647 new_ref_i = found_i;
648 map_index(scratch_cp, ref_i, found_i);
649 } else {
650 // no match found so we have to append this entry to *merge_cp_p
651 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p);
652 // The above call to append_entry() can only append one entry
653 // so the post call query of *merge_cp_length_p is only for
654 // the sake of consistency.
655 new_ref_i = *merge_cp_length_p - 1;
656 }
657 }
658
659 // constant pool indices are u2, unless the merged constant pool overflows which
660 // we don't check for.
661 return checked_cast<u2>(new_ref_i);
662 } // end find_or_append_indirect_entry()
663
664
665 // Append a bootstrap specifier into the merge_cp BSM entries that is semantically equal
666 // to the scratch_cp BSM entries' bootstrap specifier passed by the old_bs_i index.
667 // Recursively append new merge_cp entries referenced by the new bootstrap specifier.
668 int VM_RedefineClasses::append_bsm_entry(const constantPoolHandle& scratch_cp, const int old_bs_i,
669 constantPoolHandle *merge_cp_p, int *merge_cp_length_p) {
670
671 BSMAttributeEntry* old_bsme = scratch_cp->bsm_attribute_entry(old_bs_i);
672 u2 old_ref_i = old_bsme->bootstrap_method_index();
673 u2 new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
674 merge_cp_length_p);
675 if (new_ref_i != old_ref_i) {
676 log_trace(redefine, class, constantpool)
677 ("BSM attribute entry@%d bootstrap method ref_index change: %d to %d", _bsmae_iter.current_offset() - 1, old_ref_i, new_ref_i);
678 }
679
680 const int new_bs_i = _bsmae_iter.current_offset();
681 BSMAttributeEntry* new_bsme =
682 _bsmae_iter.reserve_new_entry(new_ref_i, old_bsme->argument_count());
683 assert(new_bsme != nullptr, "must be");
684 for (int i = 0; i < new_bsme->argument_count(); i++) {
685 u2 old_arg_ref_i = old_bsme->argument(i);
686 u2 new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p,
687 merge_cp_length_p);
688 new_bsme->set_argument(i, new_arg_ref_i);
689
690 if (new_arg_ref_i != old_arg_ref_i) {
691 log_trace(redefine, class, constantpool)
692 ("BSM attribute entry@%d bootstrap method argument ref_index change: %d to %d",
693 _bsmae_iter.current_offset() - 1, old_arg_ref_i, new_arg_ref_i);
694 }
695 }
696 // This is only for the logging
697 map_bsm_index(old_bs_i, new_bs_i);
698 return new_bs_i;
699 } // end append_bsm_entry()
700
701
702 int VM_RedefineClasses::find_or_append_bsm_entry(const constantPoolHandle& scratch_cp,
703 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) {
704
705 const int max_offset_in_merge = _bsmae_iter.current_offset();
706 int new_bs_i = old_bs_i; // bootstrap specifier index
707 // Has the old_bs_i index been used already? Check if it's the same so we know
708 // whether or not a remapping is required.
709 bool match = (old_bs_i < max_offset_in_merge) &&
710 scratch_cp->compare_bootstrap_entry_to(old_bs_i, *merge_cp_p, old_bs_i);
711
712 if (!match) {
713 // forward reference in *merge_cp_p or not a direct match
714 int found_i = scratch_cp->find_matching_bsm_entry(old_bs_i, *merge_cp_p,
715 max_offset_in_merge);
716 if (found_i != -1) {
717 guarantee(found_i != old_bs_i, "compare_bootstrap_entry_to() and find_matching_bsm_entry() disagree");
718 // found a matching BSM entry somewhere else in *merge_cp_p so just need a mapping
719 new_bs_i = found_i;
720 map_bsm_index(old_bs_i, found_i);
721 } else {
722 // no match found so we have to append this bootstrap specifier to *merge_cp_p
723 new_bs_i = append_bsm_entry(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p);
724 }
725 }
726 return new_bs_i;
727 } // end find_or_append_bsm_entry()
728
729
730 void VM_RedefineClasses::finalize_bsm_entries_merge(const constantPoolHandle& merge_cp, TRAPS) {
731 if (merge_cp->bsm_entries().number_of_entries() == 0) {
732 return;
733 }
734 // Finished extending the BSMAEs
735 merge_cp->end_extension(_bsmae_iter, CHECK);
736
737 if (log_is_enabled(Trace, redefine, class, constantpool)) {
738 // don't want to loop unless we are tracing
739 int count = 0;
740 for (int i = 1; i < _bsm_index_map_p->length(); i++) {
741 int value = _bsm_index_map_p->at(i);
742 if (value != -1) {
743 log_trace(redefine, class, constantpool)("bsm_index_map[%d]: old=%d new=%d", count, i, value);
744 count++;
745 }
746 }
747 }
748 // Clean-up
749 _bsm_index_map_p = nullptr;
750 _bsm_index_map_count = 0;
751 _bsmae_iter = BSMAttributeEntries::InsertionIterator();
752 } // end finalize_bsmentries_merge()
753
754 // Symbol* comparator for qsort
755 // The caller must have an active ResourceMark.
756 static int symcmp(const void* a, const void* b) {
757 char* astr = (*(Symbol**)a)->as_C_string();
758 char* bstr = (*(Symbol**)b)->as_C_string();
759 return strcmp(astr, bstr);
760 }
761
762 // The caller must have an active ResourceMark.
763 static jvmtiError check_attribute_arrays(const char* attr_name,
764 InstanceKlass* the_class, InstanceKlass* scratch_class,
765 Array<u2>* the_array, Array<u2>* scr_array) {
766 bool the_array_exists = the_array != Universe::the_empty_short_array();
767 bool scr_array_exists = scr_array != Universe::the_empty_short_array();
768
769 int array_len = the_array->length();
770 if (the_array_exists && scr_array_exists) {
771 if (array_len != scr_array->length()) {
772 log_trace(redefine, class)
773 ("redefined class %s attribute change error: %s len=%d changed to len=%d",
774 the_class->external_name(), attr_name, array_len, scr_array->length());
775 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
776 }
777
778 // The order of entries in the attribute array is not specified so we
779 // have to explicitly check for the same contents. We do this by copying
780 // the referenced symbols into their own arrays, sorting them and then
781 // comparing each element pair.
782
783 Symbol** the_syms = NEW_RESOURCE_ARRAY_RETURN_NULL(Symbol*, array_len);
784 Symbol** scr_syms = NEW_RESOURCE_ARRAY_RETURN_NULL(Symbol*, array_len);
785
786 if (the_syms == nullptr || scr_syms == nullptr) {
787 return JVMTI_ERROR_OUT_OF_MEMORY;
788 }
789
790 for (int i = 0; i < array_len; i++) {
791 int the_cp_index = the_array->at(i);
792 int scr_cp_index = scr_array->at(i);
793 the_syms[i] = the_class->constants()->klass_name_at(the_cp_index);
794 scr_syms[i] = scratch_class->constants()->klass_name_at(scr_cp_index);
795 }
796
797 qsort(the_syms, array_len, sizeof(Symbol*), symcmp);
798 qsort(scr_syms, array_len, sizeof(Symbol*), symcmp);
799
800 for (int i = 0; i < array_len; i++) {
801 if (the_syms[i] != scr_syms[i]) {
802 log_info(redefine, class)
803 ("redefined class %s attribute change error: %s[%d]: %s changed to %s",
804 the_class->external_name(), attr_name, i,
805 the_syms[i]->as_C_string(), scr_syms[i]->as_C_string());
806 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
807 }
808 }
809 } else if (the_array_exists ^ scr_array_exists) {
810 const char* action_str = (the_array_exists) ? "removed" : "added";
811 log_info(redefine, class)
812 ("redefined class %s attribute change error: %s attribute %s",
813 the_class->external_name(), attr_name, action_str);
814 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
815 }
816 return JVMTI_ERROR_NONE;
817 }
818
819 static jvmtiError check_nest_attributes(InstanceKlass* the_class,
820 InstanceKlass* scratch_class) {
821 // Check whether the class NestHost attribute has been changed.
822 Thread* thread = Thread::current();
823 ResourceMark rm(thread);
824 u2 the_nest_host_idx = the_class->nest_host_index();
825 u2 scr_nest_host_idx = scratch_class->nest_host_index();
826
827 if (the_nest_host_idx != 0 && scr_nest_host_idx != 0) {
828 Symbol* the_sym = the_class->constants()->klass_name_at(the_nest_host_idx);
829 Symbol* scr_sym = scratch_class->constants()->klass_name_at(scr_nest_host_idx);
830 if (the_sym != scr_sym) {
831 log_info(redefine, class, nestmates)
832 ("redefined class %s attribute change error: NestHost class: %s replaced with: %s",
833 the_class->external_name(), the_sym->as_C_string(), scr_sym->as_C_string());
834 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
835 }
836 } else if ((the_nest_host_idx == 0) ^ (scr_nest_host_idx == 0)) {
837 const char* action_str = (the_nest_host_idx != 0) ? "removed" : "added";
838 log_info(redefine, class, nestmates)
839 ("redefined class %s attribute change error: NestHost attribute %s",
840 the_class->external_name(), action_str);
841 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
842 }
843
844 // Check whether the class NestMembers attribute has been changed.
845 return check_attribute_arrays("NestMembers",
846 the_class, scratch_class,
847 the_class->nest_members(),
848 scratch_class->nest_members());
849 }
850
851 // Return an error status if the class Record attribute was changed.
852 static jvmtiError check_record_attribute(InstanceKlass* the_class, InstanceKlass* scratch_class) {
853 // Get lists of record components.
854 Array<RecordComponent*>* the_record = the_class->record_components();
855 Array<RecordComponent*>* scr_record = scratch_class->record_components();
856 bool the_record_exists = the_record != nullptr;
857 bool scr_record_exists = scr_record != nullptr;
858
859 if (the_record_exists && scr_record_exists) {
860 int the_num_components = the_record->length();
861 int scr_num_components = scr_record->length();
862 if (the_num_components != scr_num_components) {
863 log_info(redefine, class, record)
864 ("redefined class %s attribute change error: Record num_components=%d changed to num_components=%d",
865 the_class->external_name(), the_num_components, scr_num_components);
866 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
867 }
868
869 // Compare each field in each record component.
870 ConstantPool* the_cp = the_class->constants();
871 ConstantPool* scr_cp = scratch_class->constants();
872 for (int x = 0; x < the_num_components; x++) {
873 RecordComponent* the_component = the_record->at(x);
874 RecordComponent* scr_component = scr_record->at(x);
875 const Symbol* const the_name = the_cp->symbol_at(the_component->name_index());
876 const Symbol* const scr_name = scr_cp->symbol_at(scr_component->name_index());
877 const Symbol* const the_descr = the_cp->symbol_at(the_component->descriptor_index());
878 const Symbol* const scr_descr = scr_cp->symbol_at(scr_component->descriptor_index());
879 if (the_name != scr_name || the_descr != scr_descr) {
880 log_info(redefine, class, record)
881 ("redefined class %s attribute change error: Record name_index, descriptor_index, and/or attributes_count changed",
882 the_class->external_name());
883 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
884 }
885
886 int the_gen_sig = the_component->generic_signature_index();
887 int scr_gen_sig = scr_component->generic_signature_index();
888 const Symbol* const the_gen_sig_sym = (the_gen_sig == 0 ? nullptr :
889 the_cp->symbol_at(the_component->generic_signature_index()));
890 const Symbol* const scr_gen_sig_sym = (scr_gen_sig == 0 ? nullptr :
891 scr_cp->symbol_at(scr_component->generic_signature_index()));
892 if (the_gen_sig_sym != scr_gen_sig_sym) {
893 log_info(redefine, class, record)
894 ("redefined class %s attribute change error: Record generic_signature attribute changed",
895 the_class->external_name());
896 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
897 }
898
899 // It's okay if a record component's annotations were changed.
900 }
901
902 } else if (the_record_exists ^ scr_record_exists) {
903 const char* action_str = (the_record_exists) ? "removed" : "added";
904 log_info(redefine, class, record)
905 ("redefined class %s attribute change error: Record attribute %s",
906 the_class->external_name(), action_str);
907 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
908 }
909
910 return JVMTI_ERROR_NONE;
911 }
912
913
914 static jvmtiError check_permitted_subclasses_attribute(InstanceKlass* the_class,
915 InstanceKlass* scratch_class) {
916 Thread* thread = Thread::current();
917 ResourceMark rm(thread);
918
919 // Check whether the class PermittedSubclasses attribute has been changed.
920 return check_attribute_arrays("PermittedSubclasses",
921 the_class, scratch_class,
922 the_class->permitted_subclasses(),
923 scratch_class->permitted_subclasses());
924 }
925
926 static bool can_add_or_delete(Method* m) {
927 // Compatibility mode
928 return (AllowRedefinitionToAddDeleteMethods &&
929 (m->is_private() && (m->is_static() || m->is_final())));
930 }
931
932 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions(
933 InstanceKlass* the_class,
934 InstanceKlass* scratch_class) {
935 int i;
936
937 // Check superclasses, or rather their names, since superclasses themselves can be
938 // requested to replace.
939 // Check for null superclass first since this might be java.lang.Object
940 if (the_class->super() != scratch_class->super() &&
941 (the_class->super() == nullptr || scratch_class->super() == nullptr ||
942 the_class->super()->name() !=
943 scratch_class->super()->name())) {
944 log_info(redefine, class, normalize)
945 ("redefined class %s superclass change error: superclass changed from %s to %s.",
946 the_class->external_name(),
947 the_class->super() == nullptr ? "null" : the_class->super()->external_name(),
948 scratch_class->super() == nullptr ? "null" : scratch_class->super()->external_name());
949 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
950 }
951
952 // Check if the number, names and order of directly implemented interfaces are the same.
953 // I think in principle we should just check if the sets of names of directly implemented
954 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the
955 // .java file, also changes in .class file) should not matter. However, comparing sets is
956 // technically a bit more difficult, and, more importantly, I am not sure at present that the
957 // order of interfaces does not matter on the implementation level, i.e. that the VM does not
958 // rely on it somewhere.
959 Array<InstanceKlass*>* k_interfaces = the_class->local_interfaces();
960 Array<InstanceKlass*>* k_new_interfaces = scratch_class->local_interfaces();
961 int n_intfs = k_interfaces->length();
962 if (n_intfs != k_new_interfaces->length()) {
963 log_info(redefine, class, normalize)
964 ("redefined class %s interfaces change error: number of implemented interfaces changed from %d to %d.",
965 the_class->external_name(), n_intfs, k_new_interfaces->length());
966 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
967 }
968 for (i = 0; i < n_intfs; i++) {
969 if (k_interfaces->at(i)->name() !=
970 k_new_interfaces->at(i)->name()) {
971 log_info(redefine, class, normalize)
972 ("redefined class %s interfaces change error: interface changed from %s to %s.",
973 the_class->external_name(),
974 k_interfaces->at(i)->external_name(), k_new_interfaces->at(i)->external_name());
975 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
976 }
977 }
978
979 // Check whether class is in the error init state.
980 if (the_class->is_in_error_state()) {
981 log_info(redefine, class, normalize)
982 ("redefined class %s is in error init state.", the_class->external_name());
983 // TBD #5057930: special error code is needed in 1.6
984 return JVMTI_ERROR_INVALID_CLASS;
985 }
986
987 // Check whether the nest-related attributes have been changed.
988 jvmtiError err = check_nest_attributes(the_class, scratch_class);
989 if (err != JVMTI_ERROR_NONE) {
990 return err;
991 }
992
993 // Check whether the Record attribute has been changed.
994 err = check_record_attribute(the_class, scratch_class);
995 if (err != JVMTI_ERROR_NONE) {
996 return err;
997 }
998
999 // Check whether the PermittedSubclasses attribute has been changed.
1000 err = check_permitted_subclasses_attribute(the_class, scratch_class);
1001 if (err != JVMTI_ERROR_NONE) {
1002 return err;
1003 }
1004
1005 // Check whether class modifiers are the same.
1006 u2 old_flags = the_class->access_flags().as_class_flags();
1007 u2 new_flags = scratch_class->access_flags().as_class_flags();
1008 if (old_flags != new_flags) {
1009 log_info(redefine, class, normalize)
1010 ("redefined class %s modifiers change error: modifiers changed from %d to %d.",
1011 the_class->external_name(), old_flags, new_flags);
1012 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED;
1013 }
1014
1015 // Check if the number, names, types and order of fields declared in these classes
1016 // are the same.
1017 JavaFieldStream old_fs(the_class);
1018 JavaFieldStream new_fs(scratch_class);
1019 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) {
1020 // name and signature
1021 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index());
1022 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index());
1023 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index());
1024 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index());
1025 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) {
1026 log_info(redefine, class, normalize)
1027 ("redefined class %s fields change error: field %s %s changed to %s %s.",
1028 the_class->external_name(),
1029 sig_sym1->as_C_string(), name_sym1->as_C_string(),
1030 sig_sym2->as_C_string(), name_sym2->as_C_string());
1031 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
1032 }
1033 // offset
1034 if (old_fs.offset() != new_fs.offset()) {
1035 log_info(redefine, class, normalize)
1036 ("redefined class %s field %s change error: offset changed from %d to %d.",
1037 the_class->external_name(), name_sym2->as_C_string(), old_fs.offset(), new_fs.offset());
1038 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
1039 }
1040 // access
1041 old_flags = old_fs.access_flags().as_field_flags();
1042 new_flags = new_fs.access_flags().as_field_flags();
1043 if (old_flags != new_flags) {
1044 log_info(redefine, class, normalize)
1045 ("redefined class %s field %s change error: modifiers changed from %d to %d.",
1046 the_class->external_name(), name_sym2->as_C_string(), old_flags, new_flags);
1047 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
1048 }
1049 }
1050
1051 // If both streams aren't done then we have a differing number of
1052 // fields.
1053 if (!old_fs.done() || !new_fs.done()) {
1054 const char* action = old_fs.done() ? "added" : "deleted";
1055 log_info(redefine, class, normalize)
1056 ("redefined class %s fields change error: some fields were %s.",
1057 the_class->external_name(), action);
1058 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
1059 }
1060
1061 // Do a parallel walk through the old and new methods. Detect
1062 // cases where they match (exist in both), have been added in
1063 // the new methods, or have been deleted (exist only in the
1064 // old methods). The class file parser places methods in order
1065 // by method name, but does not order overloaded methods by
1066 // signature. In order to determine what fate befell the methods,
1067 // this code places the overloaded new methods that have matching
1068 // old methods in the same order as the old methods and places
1069 // new overloaded methods at the end of overloaded methods of
1070 // that name. The code for this order normalization is adapted
1071 // from the algorithm used in InstanceKlass::find_method().
1072 // Since we are swapping out of order entries as we find them,
1073 // we only have to search forward through the overloaded methods.
1074 // Methods which are added and have the same name as an existing
1075 // method (but different signature) will be put at the end of
1076 // the methods with that name, and the name mismatch code will
1077 // handle them.
1078 Array<Method*>* k_old_methods(the_class->methods());
1079 Array<Method*>* k_new_methods(scratch_class->methods());
1080 int n_old_methods = k_old_methods->length();
1081 int n_new_methods = k_new_methods->length();
1082 Thread* thread = Thread::current();
1083
1084 int ni = 0;
1085 int oi = 0;
1086 while (true) {
1087 Method* k_old_method;
1088 Method* k_new_method;
1089 enum { matched, added, deleted, undetermined } method_was = undetermined;
1090
1091 if (oi >= n_old_methods) {
1092 if (ni >= n_new_methods) {
1093 break; // we've looked at everything, done
1094 }
1095 // New method at the end
1096 k_new_method = k_new_methods->at(ni);
1097 method_was = added;
1098 } else if (ni >= n_new_methods) {
1099 // Old method, at the end, is deleted
1100 k_old_method = k_old_methods->at(oi);
1101 method_was = deleted;
1102 } else {
1103 // There are more methods in both the old and new lists
1104 k_old_method = k_old_methods->at(oi);
1105 k_new_method = k_new_methods->at(ni);
1106 if (k_old_method->name() != k_new_method->name()) {
1107 // Methods are sorted by method name, so a mismatch means added
1108 // or deleted
1109 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) {
1110 method_was = added;
1111 } else {
1112 method_was = deleted;
1113 }
1114 } else if (k_old_method->signature() == k_new_method->signature()) {
1115 // Both the name and signature match
1116 method_was = matched;
1117 } else {
1118 // The name matches, but the signature doesn't, which means we have to
1119 // search forward through the new overloaded methods.
1120 int nj; // outside the loop for post-loop check
1121 for (nj = ni + 1; nj < n_new_methods; nj++) {
1122 Method* m = k_new_methods->at(nj);
1123 if (k_old_method->name() != m->name()) {
1124 // reached another method name so no more overloaded methods
1125 method_was = deleted;
1126 break;
1127 }
1128 if (k_old_method->signature() == m->signature()) {
1129 // found a match so swap the methods
1130 k_new_methods->at_put(ni, m);
1131 k_new_methods->at_put(nj, k_new_method);
1132 k_new_method = m;
1133 method_was = matched;
1134 break;
1135 }
1136 }
1137
1138 if (nj >= n_new_methods) {
1139 // reached the end without a match; so method was deleted
1140 method_was = deleted;
1141 }
1142 }
1143 }
1144
1145 switch (method_was) {
1146 case matched:
1147 // methods match, be sure modifiers do too
1148 old_flags = k_old_method->access_flags().as_method_flags();
1149 new_flags = k_new_method->access_flags().as_method_flags();
1150 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) {
1151 log_info(redefine, class, normalize)
1152 ("redefined class %s method %s modifiers error: modifiers changed from %d to %d",
1153 the_class->external_name(), k_old_method->name_and_sig_as_C_string(), old_flags, new_flags);
1154 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED;
1155 }
1156 {
1157 u2 new_num = k_new_method->method_idnum();
1158 u2 old_num = k_old_method->method_idnum();
1159 if (new_num != old_num) {
1160 Method* idnum_owner = scratch_class->method_with_idnum(old_num);
1161 if (idnum_owner != nullptr) {
1162 // There is already a method assigned this idnum -- switch them
1163 // Take current and original idnum from the new_method
1164 idnum_owner->set_method_idnum(new_num);
1165 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum());
1166 }
1167 // Take current and original idnum from the old_method
1168 k_new_method->set_method_idnum(old_num);
1169 k_new_method->set_orig_method_idnum(k_old_method->orig_method_idnum());
1170 if (thread->has_pending_exception()) {
1171 return JVMTI_ERROR_OUT_OF_MEMORY;
1172 }
1173 }
1174 }
1175 log_trace(redefine, class, normalize)
1176 ("Method matched: new: %s [%d] == old: %s [%d]",
1177 k_new_method->name_and_sig_as_C_string(), ni, k_old_method->name_and_sig_as_C_string(), oi);
1178 // advance to next pair of methods
1179 ++oi;
1180 ++ni;
1181 break;
1182 case added:
1183 // method added, see if it is OK
1184 if (!can_add_or_delete(k_new_method)) {
1185 log_info(redefine, class, normalize)
1186 ("redefined class %s methods error: added method: %s [%d]",
1187 the_class->external_name(), k_new_method->name_and_sig_as_C_string(), ni);
1188 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
1189 }
1190 {
1191 u2 num = the_class->next_method_idnum();
1192 if (num == ConstMethod::UNSET_IDNUM) {
1193 // cannot add any more methods
1194 log_info(redefine, class, normalize)
1195 ("redefined class %s methods error: can't create ID for new method %s [%d]",
1196 the_class->external_name(), k_new_method->name_and_sig_as_C_string(), ni);
1197 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
1198 }
1199 u2 new_num = k_new_method->method_idnum();
1200 Method* idnum_owner = scratch_class->method_with_idnum(num);
1201 if (idnum_owner != nullptr) {
1202 // There is already a method assigned this idnum -- switch them
1203 // Take current and original idnum from the new_method
1204 idnum_owner->set_method_idnum(new_num);
1205 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum());
1206 }
1207 k_new_method->set_method_idnum(num);
1208 k_new_method->set_orig_method_idnum(num);
1209 if (thread->has_pending_exception()) {
1210 return JVMTI_ERROR_OUT_OF_MEMORY;
1211 }
1212 }
1213 log_trace(redefine, class, normalize)
1214 ("Method added: new: %s [%d]", k_new_method->name_and_sig_as_C_string(), ni);
1215 ++ni; // advance to next new method
1216 break;
1217 case deleted:
1218 // method deleted, see if it is OK
1219 if (!can_add_or_delete(k_old_method)) {
1220 log_info(redefine, class, normalize)
1221 ("redefined class %s methods error: deleted method %s [%d]",
1222 the_class->external_name(), k_old_method->name_and_sig_as_C_string(), oi);
1223 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED;
1224 }
1225 log_trace(redefine, class, normalize)
1226 ("Method deleted: old: %s [%d]", k_old_method->name_and_sig_as_C_string(), oi);
1227 ++oi; // advance to next old method
1228 break;
1229 default:
1230 ShouldNotReachHere();
1231 }
1232 }
1233
1234 return JVMTI_ERROR_NONE;
1235 }
1236
1237
1238 // Find new constant pool index value for old constant pool index value
1239 // by searching the index map. Returns zero (0) if there is no mapped
1240 // value for the old constant pool index.
1241 u2 VM_RedefineClasses::find_new_index(int old_index) {
1242 if (_index_map_count == 0) {
1243 // map is empty so nothing can be found
1244 return 0;
1245 }
1246
1247 if (old_index < 1 || old_index >= _index_map_p->length()) {
1248 // The old_index is out of range so it is not mapped. This should
1249 // not happen in regular constant pool merging use, but it can
1250 // happen if a corrupt annotation is processed.
1251 return 0;
1252 }
1253
1254 int value = _index_map_p->at(old_index);
1255 if (value == -1) {
1256 // the old_index is not mapped
1257 return 0;
1258 }
1259
1260 // constant pool indices are u2, unless the merged constant pool overflows which
1261 // we don't check for.
1262 return checked_cast<u2>(value);
1263 } // end find_new_index()
1264
1265
1266 // Find new bootstrap specifier index value for old bootstrap specifier index
1267 // value by searching the index map. Returns unused index (-1) if there is
1268 // no mapped value for the old bootstrap specifier index.
1269 int VM_RedefineClasses::find_new_bsm_index(int old_index) {
1270 if (_bsm_index_map_count == 0) {
1271 // map is empty so nothing can be found
1272 return -1;
1273 }
1274
1275 if (old_index == -1 || old_index >= _bsm_index_map_p->length()) {
1276 // The old_index is out of range so it is not mapped.
1277 // This should not happen in regular constant pool merging use.
1278 return -1;
1279 }
1280
1281 int value = _bsm_index_map_p->at(old_index);
1282 if (value == -1) {
1283 // the old_index is not mapped
1284 return -1;
1285 }
1286
1287 return value;
1288 } // end find_new_bsm_index()
1289
1290
1291 // The bug 6214132 caused the verification to fail.
1292 // 1. What's done in RedefineClasses() before verification:
1293 // a) A reference to the class being redefined (_the_class) and a
1294 // reference to new version of the class (_scratch_class) are
1295 // saved here for use during the bytecode verification phase of
1296 // RedefineClasses.
1297 // b) The _java_mirror field from _the_class is copied to the
1298 // _java_mirror field in _scratch_class. This means that a jclass
1299 // returned for _the_class or _scratch_class will refer to the
1300 // same Java mirror. The verifier will see the "one true mirror"
1301 // for the class being verified.
1302 // 2. See comments in JvmtiThreadState for what is done during verification.
1303
1304 class RedefineVerifyMark : public StackObj {
1305 private:
1306 JvmtiThreadState* _state;
1307 InstanceKlass* _scratch_class;
1308 OopHandle _scratch_mirror;
1309
1310 public:
1311
1312 RedefineVerifyMark(InstanceKlass* the_class, InstanceKlass* scratch_class,
1313 JvmtiThreadState* state) : _state(state), _scratch_class(scratch_class)
1314 {
1315 _state->set_class_versions_map(the_class, scratch_class);
1316 _scratch_mirror = the_class->java_mirror_handle(); // this is a copy that is swapped
1317 _scratch_class->swap_java_mirror_handle(_scratch_mirror);
1318 }
1319
1320 ~RedefineVerifyMark() {
1321 // Restore the scratch class's mirror, so when scratch_class is removed
1322 // the correct mirror pointing to it can be cleared.
1323 _scratch_class->swap_java_mirror_handle(_scratch_mirror);
1324 _state->clear_class_versions_map();
1325 }
1326 };
1327
1328
1329 jvmtiError VM_RedefineClasses::load_new_class_versions() {
1330
1331 // For consistency allocate memory using os::malloc wrapper.
1332 _scratch_classes = (InstanceKlass**)
1333 os::malloc(sizeof(InstanceKlass*) * _class_count, mtClass);
1334 if (_scratch_classes == nullptr) {
1335 return JVMTI_ERROR_OUT_OF_MEMORY;
1336 }
1337 // Zero initialize the _scratch_classes array.
1338 for (int i = 0; i < _class_count; i++) {
1339 _scratch_classes[i] = nullptr;
1340 }
1341
1342 JavaThread* current = JavaThread::current();
1343 ResourceMark rm(current);
1344
1345 JvmtiThreadState *state = JvmtiThreadState::state_for(current);
1346 // state can only be null if the current thread is exiting which
1347 // should not happen since we're trying to do a RedefineClasses
1348 guarantee(state != nullptr, "exiting thread calling load_new_class_versions");
1349 for (int i = 0; i < _class_count; i++) {
1350 // Create HandleMark so that any handles created while loading new class
1351 // versions are deleted. Constant pools are deallocated while merging
1352 // constant pools
1353 HandleMark hm(current);
1354 InstanceKlass* the_class = get_ik(_class_defs[i].klass);
1355 physical_memory_size_type avail_mem = 0;
1356 // Return value ignored - defaulting to 0 on failure.
1357 (void)os::available_memory(avail_mem);
1358 log_debug(redefine, class, load)
1359 ("loading name=%s kind=%d (avail_mem=" PHYS_MEM_TYPE_FORMAT "K)",
1360 the_class->external_name(), _class_load_kind, avail_mem >> 10);
1361
1362 ClassFileStream st((u1*)_class_defs[i].class_bytes,
1363 _class_defs[i].class_byte_count,
1364 "__VM_RedefineClasses__");
1365
1366 // Set redefined class handle in JvmtiThreadState class.
1367 // This redefined class is sent to agent event handler for class file
1368 // load hook event.
1369 state->set_class_being_redefined(the_class, _class_load_kind);
1370
1371 JavaThread* THREAD = current; // For exception macros.
1372 ExceptionMark em(THREAD);
1373 Handle protection_domain(THREAD, the_class->protection_domain());
1374 ClassLoadInfo cl_info(protection_domain);
1375 // Parse and create a class from the bytes, but this class isn't added
1376 // to the dictionary, so do not call resolve_from_stream.
1377 InstanceKlass* scratch_class = KlassFactory::create_from_stream(&st,
1378 the_class->name(),
1379 the_class->class_loader_data(),
1380 cl_info,
1381 THREAD);
1382
1383 // Clear class_being_redefined just to be sure.
1384 state->clear_class_being_redefined();
1385
1386 // TODO: if this is retransform, and nothing changed we can skip it
1387
1388 // Need to clean up allocated InstanceKlass if there's an error so assign
1389 // the result here. Caller deallocates all the scratch classes in case of
1390 // an error.
1391 _scratch_classes[i] = scratch_class;
1392
1393 if (HAS_PENDING_EXCEPTION) {
1394 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1395 log_info(redefine, class, load, exceptions)("create_from_stream exception: '%s'", ex_name->as_C_string());
1396 CLEAR_PENDING_EXCEPTION;
1397
1398 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) {
1399 return JVMTI_ERROR_UNSUPPORTED_VERSION;
1400 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) {
1401 return JVMTI_ERROR_INVALID_CLASS_FORMAT;
1402 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) {
1403 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION;
1404 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
1405 // The message will be "XXX (wrong name: YYY)"
1406 return JVMTI_ERROR_NAMES_DONT_MATCH;
1407 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1408 return JVMTI_ERROR_OUT_OF_MEMORY;
1409 } else { // Just in case more exceptions can be thrown..
1410 return JVMTI_ERROR_FAILS_VERIFICATION;
1411 }
1412 }
1413
1414 // Ensure class is linked before redefine
1415 if (!the_class->is_linked()) {
1416 the_class->link_class(THREAD);
1417 if (HAS_PENDING_EXCEPTION) {
1418 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1419 oop message = java_lang_Throwable::message(PENDING_EXCEPTION);
1420 if (message != nullptr) {
1421 char* ex_msg = java_lang_String::as_utf8_string(message);
1422 log_info(redefine, class, load, exceptions)("link_class exception: '%s %s'",
1423 ex_name->as_C_string(), ex_msg);
1424 } else {
1425 log_info(redefine, class, load, exceptions)("link_class exception: '%s'",
1426 ex_name->as_C_string());
1427 }
1428 CLEAR_PENDING_EXCEPTION;
1429 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1430 return JVMTI_ERROR_OUT_OF_MEMORY;
1431 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
1432 return JVMTI_ERROR_INVALID_CLASS;
1433 } else {
1434 return JVMTI_ERROR_INTERNAL;
1435 }
1436 }
1437 }
1438
1439 // Do the validity checks in compare_and_normalize_class_versions()
1440 // before verifying the byte codes. By doing these checks first, we
1441 // limit the number of functions that require redirection from
1442 // the_class to scratch_class. In particular, we don't have to
1443 // modify JNI GetSuperclass() and thus won't change its performance.
1444 jvmtiError res = compare_and_normalize_class_versions(the_class,
1445 scratch_class);
1446 if (res != JVMTI_ERROR_NONE) {
1447 return res;
1448 }
1449
1450 // verify what the caller passed us
1451 {
1452 // The bug 6214132 caused the verification to fail.
1453 // Information about the_class and scratch_class is temporarily
1454 // recorded into jvmtiThreadState. This data is used to redirect
1455 // the_class to scratch_class in the JVM_* functions called by the
1456 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed
1457 // description.
1458 RedefineVerifyMark rvm(the_class, scratch_class, state);
1459 Verifier::verify(scratch_class, true, THREAD);
1460 }
1461
1462 if (HAS_PENDING_EXCEPTION) {
1463 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1464 log_info(redefine, class, load, exceptions)("verify_byte_codes exception: '%s'", ex_name->as_C_string());
1465 CLEAR_PENDING_EXCEPTION;
1466 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1467 return JVMTI_ERROR_OUT_OF_MEMORY;
1468 } else {
1469 // tell the caller the bytecodes are bad
1470 return JVMTI_ERROR_FAILS_VERIFICATION;
1471 }
1472 }
1473
1474 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD);
1475 if (HAS_PENDING_EXCEPTION) {
1476 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1477 log_info(redefine, class, load, exceptions)("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string());
1478 CLEAR_PENDING_EXCEPTION;
1479 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1480 return JVMTI_ERROR_OUT_OF_MEMORY;
1481 } else {
1482 return JVMTI_ERROR_INTERNAL;
1483 }
1484 }
1485
1486 #ifdef ASSERT
1487 {
1488 // verify what we have done during constant pool merging
1489 {
1490 RedefineVerifyMark rvm(the_class, scratch_class, state);
1491 Verifier::verify(scratch_class, true, THREAD);
1492 }
1493
1494 if (HAS_PENDING_EXCEPTION) {
1495 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1496 log_info(redefine, class, load, exceptions)
1497 ("verify_byte_codes post merge-CP exception: '%s'", ex_name->as_C_string());
1498 CLEAR_PENDING_EXCEPTION;
1499 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1500 return JVMTI_ERROR_OUT_OF_MEMORY;
1501 } else {
1502 // tell the caller that constant pool merging screwed up
1503 return JVMTI_ERROR_INTERNAL;
1504 }
1505 }
1506 }
1507 #endif // ASSERT
1508
1509 Rewriter::rewrite(scratch_class, THREAD);
1510 if (!HAS_PENDING_EXCEPTION) {
1511 scratch_class->link_methods(THREAD);
1512 }
1513 if (HAS_PENDING_EXCEPTION) {
1514 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1515 log_info(redefine, class, load, exceptions)
1516 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string());
1517 CLEAR_PENDING_EXCEPTION;
1518 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1519 return JVMTI_ERROR_OUT_OF_MEMORY;
1520 } else {
1521 return JVMTI_ERROR_INTERNAL;
1522 }
1523 }
1524 // Return value ignored - defaulting to 0 on failure.
1525 (void)os::available_memory(avail_mem);
1526 log_debug(redefine, class, load)
1527 ("loaded name=%s (avail_mem=" PHYS_MEM_TYPE_FORMAT "K)", the_class->external_name(), avail_mem >> 10);
1528 }
1529
1530 return JVMTI_ERROR_NONE;
1531 }
1532
1533
1534 // Map old_index to new_index as needed. scratch_cp is only needed
1535 // for log calls.
1536 void VM_RedefineClasses::map_index(const constantPoolHandle& scratch_cp,
1537 int old_index, int new_index) {
1538 if (find_new_index(old_index) != 0) {
1539 // old_index is already mapped
1540 return;
1541 }
1542
1543 if (old_index == new_index) {
1544 // no mapping is needed
1545 return;
1546 }
1547
1548 _index_map_p->at_put(old_index, new_index);
1549 _index_map_count++;
1550
1551 log_trace(redefine, class, constantpool)
1552 ("mapped tag %d at index %d to %d", scratch_cp->tag_at(old_index).value(), old_index, new_index);
1553 } // end map_index()
1554
1555
1556 // Map old_index to new_index as needed.
1557 void VM_RedefineClasses::map_bsm_index(int old_index, int new_index) {
1558 if (old_index == new_index) {
1559 // no mapping is needed
1560 return;
1561 }
1562 _bsm_index_map_p->at_put(old_index, new_index);
1563 _bsm_index_map_count++;
1564 log_trace(redefine, class, constantpool)("mapped bootstrap specifier at index %d to %d", old_index, new_index);
1565 } // end map_bsm_index()
1566
1567
1568 // Merge old_cp and scratch_cp and return the results of the merge via
1569 // merge_cp_p. The number of entries in merge_cp_p is returned via
1570 // merge_cp_length_p. The entries in old_cp occupy the same locations
1571 // in merge_cp_p. Also creates a map of indices from entries in
1572 // scratch_cp to the corresponding entry in merge_cp_p. Index map
1573 // entries are only created for entries in scratch_cp that occupy a
1574 // different location in merged_cp_p.
1575 bool VM_RedefineClasses::merge_constant_pools(const constantPoolHandle& old_cp,
1576 const constantPoolHandle& scratch_cp, constantPoolHandle& merge_cp_p,
1577 int& merge_cp_length_p, TRAPS) {
1578
1579 // Worst case we need old_cp->length() + scratch_cp()->length(),
1580 // but the caller might be smart so make sure we have at least
1581 // the minimum.
1582 if (merge_cp_p->length() < old_cp->length()) {
1583 assert(false, "merge area too small");
1584 return false; // robustness
1585 }
1586
1587 log_info(redefine, class, constantpool)("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(), scratch_cp->length());
1588
1589 {
1590 // Pass 0:
1591 // The old_cp is copied to *merge_cp_p; this means that any code
1592 // using old_cp does not have to change. This work looks like a
1593 // perfect fit for ConstantPool*::copy_cp_to(), but we need to
1594 // handle one special case:
1595 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass
1596 // This will make verification happy.
1597
1598 int old_i; // index into old_cp
1599
1600 // index zero (0) is not used in constantPools
1601 for (old_i = 1; old_i < old_cp->length(); old_i++) {
1602 // leave debugging crumb
1603 jbyte old_tag = old_cp->tag_at(old_i).value();
1604 switch (old_tag) {
1605 case JVM_CONSTANT_Class:
1606 case JVM_CONSTANT_UnresolvedClass:
1607 // revert the copy to JVM_CONSTANT_UnresolvedClass
1608 // May be resolving while calling this so do the same for
1609 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition)
1610 merge_cp_p->temp_unresolved_klass_at_put(old_i,
1611 old_cp->klass_name_index_at(old_i));
1612 break;
1613
1614 case JVM_CONSTANT_Double:
1615 case JVM_CONSTANT_Long:
1616 // just copy the entry to merge_cp_p, but double and long take
1617 // two constant pool entries
1618 ConstantPool::copy_entry_to(old_cp, old_i, merge_cp_p, old_i);
1619 old_i++;
1620 break;
1621
1622 default:
1623 // just copy the entry to merge_cp_p
1624 ConstantPool::copy_entry_to(old_cp, old_i, merge_cp_p, old_i);
1625 break;
1626 }
1627 } // end for each old_cp entry
1628
1629 ConstantPool::copy_bsm_entries(old_cp, merge_cp_p, CHECK_false);
1630 _bsmae_iter = merge_cp_p->start_extension(scratch_cp, CHECK_false);
1631
1632 // We don't need to sanity check that *merge_cp_length_p is within
1633 // *merge_cp_p bounds since we have the minimum on-entry check above.
1634 merge_cp_length_p = old_i;
1635 }
1636
1637 // merge_cp_len should be the same as old_cp->length() at this point
1638 // so this trace message is really a "warm-and-breathing" message.
1639 log_debug(redefine, class, constantpool)("after pass 0: merge_cp_len=%d", merge_cp_length_p);
1640
1641 int scratch_i; // index into scratch_cp
1642 {
1643 // Pass 1a:
1644 // Compare scratch_cp entries to the old_cp entries that we have
1645 // already copied to *merge_cp_p. In this pass, we are eliminating
1646 // exact duplicates (matching entry at same index) so we only
1647 // compare entries in the common indice range.
1648 int increment = 1;
1649 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length());
1650 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) {
1651 switch (scratch_cp->tag_at(scratch_i).value()) {
1652 case JVM_CONSTANT_Double:
1653 case JVM_CONSTANT_Long:
1654 // double and long take two constant pool entries
1655 increment = 2;
1656 break;
1657
1658 default:
1659 increment = 1;
1660 break;
1661 }
1662
1663 bool match = scratch_cp->compare_entry_to(scratch_i, merge_cp_p, scratch_i);
1664 if (match) {
1665 // found a match at the same index so nothing more to do
1666 continue;
1667 }
1668
1669 int found_i = scratch_cp->find_matching_entry(scratch_i, merge_cp_p);
1670 if (found_i != 0) {
1671 guarantee(found_i != scratch_i,
1672 "compare_entry_to() and find_matching_entry() do not agree");
1673
1674 // Found a matching entry somewhere else in *merge_cp_p so
1675 // just need a mapping entry.
1676 map_index(scratch_cp, scratch_i, found_i);
1677 continue;
1678 }
1679
1680 // No match found so we have to append this entry and any unique
1681 // referenced entries to merge_cp_p.
1682 append_entry(scratch_cp, scratch_i, &merge_cp_p, &merge_cp_length_p);
1683 }
1684 }
1685
1686 log_debug(redefine, class, constantpool)
1687 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1688 merge_cp_length_p, scratch_i, _index_map_count);
1689
1690 if (scratch_i < scratch_cp->length()) {
1691 // Pass 1b:
1692 // old_cp is smaller than scratch_cp so there are entries in
1693 // scratch_cp that we have not yet processed. We take care of
1694 // those now.
1695 int increment = 1;
1696 for (; scratch_i < scratch_cp->length(); scratch_i += increment) {
1697 switch (scratch_cp->tag_at(scratch_i).value()) {
1698 case JVM_CONSTANT_Double:
1699 case JVM_CONSTANT_Long:
1700 // double and long take two constant pool entries
1701 increment = 2;
1702 break;
1703
1704 default:
1705 increment = 1;
1706 break;
1707 }
1708
1709 int found_i =
1710 scratch_cp->find_matching_entry(scratch_i, merge_cp_p);
1711 if (found_i != 0) {
1712 // Found a matching entry somewhere else in merge_cp_p so
1713 // just need a mapping entry.
1714 map_index(scratch_cp, scratch_i, found_i);
1715 continue;
1716 }
1717
1718 // No match found so we have to append this entry and any unique
1719 // referenced entries to merge_cp_p.
1720 append_entry(scratch_cp, scratch_i, &merge_cp_p, &merge_cp_length_p);
1721 }
1722
1723 log_debug(redefine, class, constantpool)
1724 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1725 merge_cp_length_p, scratch_i, _index_map_count);
1726 }
1727 finalize_bsm_entries_merge(merge_cp_p, CHECK_false);
1728
1729 return true;
1730 } // end merge_constant_pools()
1731
1732
1733 // Scoped object to clean up the constant pool(s) created for merging
1734 class MergeCPCleaner {
1735 ClassLoaderData* _loader_data;
1736 ConstantPool* _cp;
1737 ConstantPool* _scratch_cp;
1738 public:
1739 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) :
1740 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(nullptr) {}
1741 ~MergeCPCleaner() {
1742 _loader_data->add_to_deallocate_list(_cp);
1743 if (_scratch_cp != nullptr) {
1744 _loader_data->add_to_deallocate_list(_scratch_cp);
1745 }
1746 }
1747 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; }
1748 };
1749
1750 // Merge constant pools between the_class and scratch_class and
1751 // potentially rewrite bytecodes in scratch_class to use the merged
1752 // constant pool.
1753 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite(
1754 InstanceKlass* the_class, InstanceKlass* scratch_class,
1755 TRAPS) {
1756 // worst case merged constant pool length is old and new combined
1757 int merge_cp_length = the_class->constants()->length()
1758 + scratch_class->constants()->length();
1759
1760 // Constant pools are not easily reused so we allocate a new one
1761 // each time.
1762 // merge_cp is created unsafe for concurrent GC processing. It
1763 // should be marked safe before discarding it. Even though
1764 // garbage, if it crosses a card boundary, it may be scanned
1765 // in order to find the start of the first complete object on the card.
1766 ClassLoaderData* loader_data = the_class->class_loader_data();
1767 ConstantPool* merge_cp_oop =
1768 ConstantPool::allocate(loader_data,
1769 merge_cp_length,
1770 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1771 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop);
1772
1773 HandleMark hm(THREAD); // make sure handles are cleared before
1774 // MergeCPCleaner clears out merge_cp_oop
1775 constantPoolHandle merge_cp(THREAD, merge_cp_oop);
1776
1777 // Get constants() from the old class because it could have been rewritten
1778 // while we were at a safepoint allocating a new constant pool.
1779 constantPoolHandle old_cp(THREAD, the_class->constants());
1780 constantPoolHandle scratch_cp(THREAD, scratch_class->constants());
1781
1782 // If the length changed, the class was redefined out from under us. Return
1783 // an error.
1784 if (merge_cp_length != the_class->constants()->length()
1785 + scratch_class->constants()->length()) {
1786 return JVMTI_ERROR_INTERNAL;
1787 }
1788
1789 // Update the version number of the constant pools (may keep scratch_cp)
1790 merge_cp->increment_and_save_version(old_cp->version());
1791 scratch_cp->increment_and_save_version(old_cp->version());
1792
1793 ResourceMark rm(THREAD);
1794 _index_map_count = 0;
1795 _index_map_p = new intArray(scratch_cp->length(), scratch_cp->length(), -1);
1796
1797 _bsm_index_map_count = 0;
1798 int bsm_data_len = scratch_cp->bsm_entries().array_length();
1799 _bsm_index_map_p = new intArray(bsm_data_len, bsm_data_len, -1);
1800
1801 // reference to the cp holder is needed for reallocating the BSM attribute
1802 merge_cp->set_pool_holder(scratch_class);
1803 bool result = merge_constant_pools(old_cp, scratch_cp, merge_cp,
1804 merge_cp_length, THREAD);
1805 merge_cp->set_pool_holder(nullptr);
1806
1807 if (!result) {
1808 // The merge can fail due to memory allocation failure or due
1809 // to robustness checks.
1810 return JVMTI_ERROR_INTERNAL;
1811 }
1812
1813 // ensure merged constant pool size does not overflow u2
1814 if (merge_cp_length > 0xFFFF) {
1815 log_warning(redefine, class, constantpool)("Merged constant pool overflow: %d entries", merge_cp_length);
1816 return JVMTI_ERROR_INTERNAL;
1817 }
1818
1819 // Set dynamic constants attribute from the original CP.
1820 if (old_cp->has_dynamic_constant()) {
1821 scratch_cp->set_has_dynamic_constant();
1822 }
1823
1824 log_info(redefine, class, constantpool)("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count);
1825
1826 if (_index_map_count == 0) {
1827 // there is nothing to map between the new and merged constant pools
1828
1829 // Copy attributes from scratch_cp to merge_cp
1830 merge_cp->copy_fields(scratch_cp());
1831
1832 if (old_cp->length() == scratch_cp->length()) {
1833 // The old and new constant pools are the same length and the
1834 // index map is empty. This means that the three constant pools
1835 // are equivalent (but not the same). Unfortunately, the new
1836 // constant pool has not gone through link resolution nor have
1837 // the new class bytecodes gone through constant pool cache
1838 // rewriting so we can't use the old constant pool with the new
1839 // class.
1840
1841 // toss the merged constant pool at return
1842 } else if (old_cp->length() < scratch_cp->length()) {
1843 // The old constant pool has fewer entries than the new constant
1844 // pool and the index map is empty. This means the new constant
1845 // pool is a superset of the old constant pool. However, the old
1846 // class bytecodes have already gone through constant pool cache
1847 // rewriting so we can't use the new constant pool with the old
1848 // class.
1849
1850 // toss the merged constant pool at return
1851 } else {
1852 // The old constant pool has more entries than the new constant
1853 // pool and the index map is empty. This means that both the old
1854 // and merged constant pools are supersets of the new constant
1855 // pool.
1856
1857 // Replace the new constant pool with a shrunken copy of the
1858 // merged constant pool
1859 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1860 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1861 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1862 // It can't be cleaned up while there are handles to it.
1863 cp_cleaner.add_scratch_cp(scratch_cp());
1864 }
1865 } else {
1866 if (log_is_enabled(Trace, redefine, class, constantpool)) {
1867 // don't want to loop unless we are tracing
1868 int count = 0;
1869 for (int i = 1; i < _index_map_p->length(); i++) {
1870 int value = _index_map_p->at(i);
1871
1872 if (value != -1) {
1873 log_trace(redefine, class, constantpool)("index_map[%d]: old=%d new=%d", count, i, value);
1874 count++;
1875 }
1876 }
1877 }
1878
1879 // We have entries mapped between the new and merged constant pools
1880 // so we have to rewrite some constant pool references.
1881 if (!rewrite_cp_refs(scratch_class)) {
1882 return JVMTI_ERROR_INTERNAL;
1883 }
1884
1885 // Copy attributes from scratch_cp to merge_cp (should be done after rewrite_cp_refs())
1886 merge_cp->copy_fields(scratch_cp());
1887
1888 // Replace the new constant pool with a shrunken copy of the
1889 // merged constant pool so now the rewritten bytecodes have
1890 // valid references; the previous new constant pool will get
1891 // GCed.
1892 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1893 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1894 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1895 // It can't be cleaned up while there are handles to it.
1896 cp_cleaner.add_scratch_cp(scratch_cp());
1897 }
1898
1899 return JVMTI_ERROR_NONE;
1900 } // end merge_cp_and_rewrite()
1901
1902
1903 // Rewrite constant pool references in klass scratch_class.
1904 bool VM_RedefineClasses::rewrite_cp_refs(InstanceKlass* scratch_class) {
1905
1906 // rewrite constant pool references in the nest attributes:
1907 if (!rewrite_cp_refs_in_nest_attributes(scratch_class)) {
1908 // propagate failure back to caller
1909 return false;
1910 }
1911
1912 // rewrite constant pool references in the Record attribute:
1913 if (!rewrite_cp_refs_in_record_attribute(scratch_class)) {
1914 // propagate failure back to caller
1915 return false;
1916 }
1917
1918 // rewrite constant pool references in the PermittedSubclasses attribute:
1919 if (!rewrite_cp_refs_in_permitted_subclasses_attribute(scratch_class)) {
1920 // propagate failure back to caller
1921 return false;
1922 }
1923
1924 // rewrite constant pool references in the methods:
1925 if (!rewrite_cp_refs_in_methods(scratch_class)) {
1926 // propagate failure back to caller
1927 return false;
1928 }
1929
1930 // rewrite constant pool references in the class_annotations:
1931 if (!rewrite_cp_refs_in_class_annotations(scratch_class)) {
1932 // propagate failure back to caller
1933 return false;
1934 }
1935
1936 // rewrite constant pool references in the fields_annotations:
1937 if (!rewrite_cp_refs_in_fields_annotations(scratch_class)) {
1938 // propagate failure back to caller
1939 return false;
1940 }
1941
1942 // rewrite constant pool references in the methods_annotations:
1943 if (!rewrite_cp_refs_in_methods_annotations(scratch_class)) {
1944 // propagate failure back to caller
1945 return false;
1946 }
1947
1948 // rewrite constant pool references in the methods_parameter_annotations:
1949 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class)) {
1950 // propagate failure back to caller
1951 return false;
1952 }
1953
1954 // rewrite constant pool references in the methods_default_annotations:
1955 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class)) {
1956 // propagate failure back to caller
1957 return false;
1958 }
1959
1960 // rewrite constant pool references in the class_type_annotations:
1961 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class)) {
1962 // propagate failure back to caller
1963 return false;
1964 }
1965
1966 // rewrite constant pool references in the fields_type_annotations:
1967 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class)) {
1968 // propagate failure back to caller
1969 return false;
1970 }
1971
1972 // rewrite constant pool references in the methods_type_annotations:
1973 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class)) {
1974 // propagate failure back to caller
1975 return false;
1976 }
1977
1978 // There can be type annotations in the Code part of a method_info attribute.
1979 // These annotations are not accessible, even by reflection.
1980 // Currently they are not even parsed by the ClassFileParser.
1981 // If runtime access is added they will also need to be rewritten.
1982
1983 // rewrite source file name index:
1984 u2 source_file_name_idx = scratch_class->source_file_name_index();
1985 if (source_file_name_idx != 0) {
1986 u2 new_source_file_name_idx = find_new_index(source_file_name_idx);
1987 if (new_source_file_name_idx != 0) {
1988 scratch_class->set_source_file_name_index(new_source_file_name_idx);
1989 }
1990 }
1991
1992 // rewrite class generic signature index:
1993 u2 generic_signature_index = scratch_class->generic_signature_index();
1994 if (generic_signature_index != 0) {
1995 u2 new_generic_signature_index = find_new_index(generic_signature_index);
1996 if (new_generic_signature_index != 0) {
1997 scratch_class->set_generic_signature_index(new_generic_signature_index);
1998 }
1999 }
2000
2001 return true;
2002 } // end rewrite_cp_refs()
2003
2004 // Rewrite constant pool references in the NestHost and NestMembers attributes.
2005 bool VM_RedefineClasses::rewrite_cp_refs_in_nest_attributes(
2006 InstanceKlass* scratch_class) {
2007
2008 u2 cp_index = scratch_class->nest_host_index();
2009 if (cp_index != 0) {
2010 scratch_class->set_nest_host_index(find_new_index(cp_index));
2011 }
2012 Array<u2>* nest_members = scratch_class->nest_members();
2013 for (int i = 0; i < nest_members->length(); i++) {
2014 u2 cp_index = nest_members->at(i);
2015 nest_members->at_put(i, find_new_index(cp_index));
2016 }
2017 return true;
2018 }
2019
2020 // Rewrite constant pool references in the Record attribute.
2021 bool VM_RedefineClasses::rewrite_cp_refs_in_record_attribute(InstanceKlass* scratch_class) {
2022 Array<RecordComponent*>* components = scratch_class->record_components();
2023 if (components != nullptr) {
2024 for (int i = 0; i < components->length(); i++) {
2025 RecordComponent* component = components->at(i);
2026 u2 cp_index = component->name_index();
2027 component->set_name_index(find_new_index(cp_index));
2028 cp_index = component->descriptor_index();
2029 component->set_descriptor_index(find_new_index(cp_index));
2030 cp_index = component->generic_signature_index();
2031 if (cp_index != 0) {
2032 component->set_generic_signature_index(find_new_index(cp_index));
2033 }
2034
2035 AnnotationArray* annotations = component->annotations();
2036 if (annotations != nullptr && annotations->length() != 0) {
2037 int byte_i = 0; // byte index into annotations
2038 if (!rewrite_cp_refs_in_annotations_typeArray(annotations, byte_i)) {
2039 log_debug(redefine, class, annotation)("bad record_component_annotations at %d", i);
2040 // propagate failure back to caller
2041 return false;
2042 }
2043 }
2044
2045 AnnotationArray* type_annotations = component->type_annotations();
2046 if (type_annotations != nullptr && type_annotations->length() != 0) {
2047 int byte_i = 0; // byte index into annotations
2048 if (!rewrite_cp_refs_in_annotations_typeArray(type_annotations, byte_i)) {
2049 log_debug(redefine, class, annotation)("bad record_component_type_annotations at %d", i);
2050 // propagate failure back to caller
2051 return false;
2052 }
2053 }
2054 }
2055 }
2056 return true;
2057 }
2058
2059 // Rewrite constant pool references in the PermittedSubclasses attribute.
2060 bool VM_RedefineClasses::rewrite_cp_refs_in_permitted_subclasses_attribute(
2061 InstanceKlass* scratch_class) {
2062
2063 Array<u2>* permitted_subclasses = scratch_class->permitted_subclasses();
2064 assert(permitted_subclasses != nullptr, "unexpected null permitted_subclasses");
2065 for (int i = 0; i < permitted_subclasses->length(); i++) {
2066 u2 cp_index = permitted_subclasses->at(i);
2067 permitted_subclasses->at_put(i, find_new_index(cp_index));
2068 }
2069 return true;
2070 }
2071
2072 // Rewrite constant pool references in the methods.
2073 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(InstanceKlass* scratch_class) {
2074
2075 Array<Method*>* methods = scratch_class->methods();
2076
2077 if (methods == nullptr || methods->length() == 0) {
2078 // no methods so nothing to do
2079 return true;
2080 }
2081
2082 JavaThread* THREAD = JavaThread::current(); // For exception macros.
2083 ExceptionMark em(THREAD);
2084
2085 // rewrite constant pool references in the methods:
2086 for (int i = methods->length() - 1; i >= 0; i--) {
2087 methodHandle method(THREAD, methods->at(i));
2088 methodHandle new_method;
2089 rewrite_cp_refs_in_method(method, &new_method, THREAD);
2090 if (!new_method.is_null()) {
2091 // the method has been replaced so save the new method version
2092 // even in the case of an exception. original method is on the
2093 // deallocation list.
2094 methods->at_put(i, new_method());
2095 }
2096 if (HAS_PENDING_EXCEPTION) {
2097 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
2098 log_info(redefine, class, load, exceptions)("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string());
2099 // Need to clear pending exception here as the super caller sets
2100 // the JVMTI_ERROR_INTERNAL if the returned value is false.
2101 CLEAR_PENDING_EXCEPTION;
2102 return false;
2103 }
2104 }
2105
2106 return true;
2107 }
2108
2109
2110 // Rewrite constant pool references in the specific method. This code
2111 // was adapted from Rewriter::rewrite_method().
2112 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method,
2113 methodHandle *new_method_p, TRAPS) {
2114
2115 *new_method_p = methodHandle(); // default is no new method
2116
2117 // We cache a pointer to the bytecodes here in code_base. If GC
2118 // moves the Method*, then the bytecodes will also move which
2119 // will likely cause a crash. We create a NoSafepointVerifier
2120 // object to detect whether we pass a possible safepoint in this
2121 // code block.
2122 NoSafepointVerifier nsv;
2123
2124 // Bytecodes and their length
2125 address code_base = method->code_base();
2126 int code_length = method->code_size();
2127
2128 int bc_length;
2129 for (int bci = 0; bci < code_length; bci += bc_length) {
2130 address bcp = code_base + bci;
2131 Bytecodes::Code c = (Bytecodes::Code)(*bcp);
2132
2133 bc_length = Bytecodes::length_for(c);
2134 if (bc_length == 0) {
2135 // More complicated bytecodes report a length of zero so
2136 // we have to try again a slightly different way.
2137 bc_length = Bytecodes::length_at(method(), bcp);
2138 }
2139
2140 assert(bc_length != 0, "impossible bytecode length");
2141
2142 switch (c) {
2143 case Bytecodes::_ldc:
2144 {
2145 u1 cp_index = *(bcp + 1);
2146 u2 new_index = find_new_index(cp_index);
2147
2148 if (StressLdcRewrite && new_index == 0) {
2149 // If we are stressing ldc -> ldc_w rewriting, then we
2150 // always need a new_index value.
2151 new_index = cp_index;
2152 }
2153 if (new_index != 0) {
2154 // the original index is mapped so we have more work to do
2155 if (!StressLdcRewrite && new_index <= max_jubyte) {
2156 // The new value can still use ldc instead of ldc_w
2157 // unless we are trying to stress ldc -> ldc_w rewriting
2158 log_trace(redefine, class, constantpool)
2159 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index);
2160 // We checked that new_index fits in a u1 so this cast is safe
2161 *(bcp + 1) = (u1)new_index;
2162 } else {
2163 log_trace(redefine, class, constantpool)
2164 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index);
2165 // the new value needs ldc_w instead of ldc
2166 u_char inst_buffer[4]; // max instruction size is 4 bytes
2167 bcp = (address)inst_buffer;
2168 // construct new instruction sequence
2169 *bcp = Bytecodes::_ldc_w;
2170 bcp++;
2171 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w.
2172 // See comment below for difference between put_Java_u2()
2173 // and put_native_u2().
2174 Bytes::put_Java_u2(bcp, new_index);
2175
2176 Relocator rc(method, nullptr /* no RelocatorListener needed */);
2177 methodHandle m;
2178 {
2179 PauseNoSafepointVerifier pnsv(&nsv);
2180
2181 // ldc is 2 bytes and ldc_w is 3 bytes
2182 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK);
2183 }
2184
2185 // return the new method so that the caller can update
2186 // the containing class
2187 *new_method_p = method = m;
2188 // switch our bytecode processing loop from the old method
2189 // to the new method
2190 code_base = method->code_base();
2191 code_length = method->code_size();
2192 bcp = code_base + bci;
2193 c = (Bytecodes::Code)(*bcp);
2194 bc_length = Bytecodes::length_for(c);
2195 assert(bc_length != 0, "sanity check");
2196 } // end we need ldc_w instead of ldc
2197 } // end if there is a mapped index
2198 } break;
2199
2200 // these bytecodes have a two-byte constant pool index
2201 case Bytecodes::_anewarray : // fall through
2202 case Bytecodes::_checkcast : // fall through
2203 case Bytecodes::_getfield : // fall through
2204 case Bytecodes::_getstatic : // fall through
2205 case Bytecodes::_instanceof : // fall through
2206 case Bytecodes::_invokedynamic : // fall through
2207 case Bytecodes::_invokeinterface: // fall through
2208 case Bytecodes::_invokespecial : // fall through
2209 case Bytecodes::_invokestatic : // fall through
2210 case Bytecodes::_invokevirtual : // fall through
2211 case Bytecodes::_ldc_w : // fall through
2212 case Bytecodes::_ldc2_w : // fall through
2213 case Bytecodes::_multianewarray : // fall through
2214 case Bytecodes::_new : // fall through
2215 case Bytecodes::_putfield : // fall through
2216 case Bytecodes::_putstatic :
2217 {
2218 address p = bcp + 1;
2219 int cp_index = Bytes::get_Java_u2(p);
2220 u2 new_index = find_new_index(cp_index);
2221 if (new_index != 0) {
2222 // the original index is mapped so update w/ new value
2223 log_trace(redefine, class, constantpool)
2224 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),p2i(bcp), cp_index, new_index);
2225 // Rewriter::rewrite_method() uses put_native_u2() in this
2226 // situation because it is reusing the constant pool index
2227 // location for a native index into the ConstantPoolCache.
2228 // Since we are updating the constant pool index prior to
2229 // verification and ConstantPoolCache initialization, we
2230 // need to keep the new index in Java byte order.
2231 Bytes::put_Java_u2(p, new_index);
2232 }
2233 } break;
2234 default:
2235 break;
2236 }
2237 } // end for each bytecode
2238 } // end rewrite_cp_refs_in_method()
2239
2240
2241 // Rewrite constant pool references in the class_annotations field.
2242 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(InstanceKlass* scratch_class) {
2243
2244 AnnotationArray* class_annotations = scratch_class->class_annotations();
2245 if (class_annotations == nullptr || class_annotations->length() == 0) {
2246 // no class_annotations so nothing to do
2247 return true;
2248 }
2249
2250 log_debug(redefine, class, annotation)("class_annotations length=%d", class_annotations->length());
2251
2252 int byte_i = 0; // byte index into class_annotations
2253 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i);
2254 }
2255
2256
2257 // Rewrite constant pool references in an annotations typeArray. This
2258 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute
2259 // that is described in section 4.8.15 of the 2nd-edition of the VM spec:
2260 //
2261 // annotations_typeArray {
2262 // u2 num_annotations;
2263 // annotation annotations[num_annotations];
2264 // }
2265 //
2266 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray(
2267 AnnotationArray* annotations_typeArray, int &byte_i_ref) {
2268
2269 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2270 // not enough room for num_annotations field
2271 log_debug(redefine, class, annotation)("length() is too small for num_annotations field");
2272 return false;
2273 }
2274
2275 u2 num_annotations = Bytes::get_Java_u2((address)
2276 annotations_typeArray->adr_at(byte_i_ref));
2277 byte_i_ref += 2;
2278
2279 log_debug(redefine, class, annotation)("num_annotations=%d", num_annotations);
2280
2281 int calc_num_annotations = 0;
2282 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
2283 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, byte_i_ref)) {
2284 log_debug(redefine, class, annotation)("bad annotation_struct at %d", calc_num_annotations);
2285 // propagate failure back to caller
2286 return false;
2287 }
2288 }
2289 assert(num_annotations == calc_num_annotations, "sanity check");
2290
2291 return true;
2292 } // end rewrite_cp_refs_in_annotations_typeArray()
2293
2294
2295 // Rewrite constant pool references in the annotation struct portion of
2296 // an annotations_typeArray. This "structure" is from section 4.8.15 of
2297 // the 2nd-edition of the VM spec:
2298 //
2299 // struct annotation {
2300 // u2 type_index;
2301 // u2 num_element_value_pairs;
2302 // {
2303 // u2 element_name_index;
2304 // element_value value;
2305 // } element_value_pairs[num_element_value_pairs];
2306 // }
2307 //
2308 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct(
2309 AnnotationArray* annotations_typeArray, int &byte_i_ref) {
2310 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) {
2311 // not enough room for smallest annotation_struct
2312 log_debug(redefine, class, annotation)("length() is too small for annotation_struct");
2313 return false;
2314 }
2315
2316 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray,
2317 byte_i_ref, "type_index");
2318
2319 u2 num_element_value_pairs = Bytes::get_Java_u2((address)
2320 annotations_typeArray->adr_at(byte_i_ref));
2321 byte_i_ref += 2;
2322
2323 log_debug(redefine, class, annotation)
2324 ("type_index=%d num_element_value_pairs=%d", type_index, num_element_value_pairs);
2325
2326 int calc_num_element_value_pairs = 0;
2327 for (; calc_num_element_value_pairs < num_element_value_pairs;
2328 calc_num_element_value_pairs++) {
2329 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2330 // not enough room for another element_name_index, let alone
2331 // the rest of another component
2332 log_debug(redefine, class, annotation)("length() is too small for element_name_index");
2333 return false;
2334 }
2335
2336 u2 element_name_index = rewrite_cp_ref_in_annotation_data(
2337 annotations_typeArray, byte_i_ref,
2338 "element_name_index");
2339
2340 log_debug(redefine, class, annotation)("element_name_index=%d", element_name_index);
2341
2342 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, byte_i_ref)) {
2343 log_debug(redefine, class, annotation)("bad element_value at %d", calc_num_element_value_pairs);
2344 // propagate failure back to caller
2345 return false;
2346 }
2347 } // end for each component
2348 assert(num_element_value_pairs == calc_num_element_value_pairs,
2349 "sanity check");
2350
2351 return true;
2352 } // end rewrite_cp_refs_in_annotation_struct()
2353
2354
2355 // Rewrite a constant pool reference at the current position in
2356 // annotations_typeArray if needed. Returns the original constant
2357 // pool reference if a rewrite was not needed or the new constant
2358 // pool reference if a rewrite was needed.
2359 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data(
2360 AnnotationArray* annotations_typeArray, int &byte_i_ref,
2361 const char * trace_mesg) {
2362
2363 address cp_index_addr = (address)
2364 annotations_typeArray->adr_at(byte_i_ref);
2365 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr);
2366 u2 new_cp_index = find_new_index(old_cp_index);
2367 if (new_cp_index != 0) {
2368 log_debug(redefine, class, annotation)("mapped old %s=%d", trace_mesg, old_cp_index);
2369 Bytes::put_Java_u2(cp_index_addr, new_cp_index);
2370 old_cp_index = new_cp_index;
2371 }
2372 byte_i_ref += 2;
2373 return old_cp_index;
2374 }
2375
2376
2377 // Rewrite constant pool references in the element_value portion of an
2378 // annotations_typeArray. This "structure" is from section 4.8.15.1 of
2379 // the 2nd-edition of the VM spec:
2380 //
2381 // struct element_value {
2382 // u1 tag;
2383 // union {
2384 // u2 const_value_index;
2385 // {
2386 // u2 type_name_index;
2387 // u2 const_name_index;
2388 // } enum_const_value;
2389 // u2 class_info_index;
2390 // annotation annotation_value;
2391 // struct {
2392 // u2 num_values;
2393 // element_value values[num_values];
2394 // } array_value;
2395 // } value;
2396 // }
2397 //
2398 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value(
2399 AnnotationArray* annotations_typeArray, int &byte_i_ref) {
2400
2401 if ((byte_i_ref + 1) > annotations_typeArray->length()) {
2402 // not enough room for a tag let alone the rest of an element_value
2403 log_debug(redefine, class, annotation)("length() is too small for a tag");
2404 return false;
2405 }
2406
2407 u1 tag = annotations_typeArray->at(byte_i_ref);
2408 byte_i_ref++;
2409 log_debug(redefine, class, annotation)("tag='%c'", tag);
2410
2411 switch (tag) {
2412 // These BaseType tag values are from Table 4.2 in VM spec:
2413 case JVM_SIGNATURE_BYTE:
2414 case JVM_SIGNATURE_CHAR:
2415 case JVM_SIGNATURE_DOUBLE:
2416 case JVM_SIGNATURE_FLOAT:
2417 case JVM_SIGNATURE_INT:
2418 case JVM_SIGNATURE_LONG:
2419 case JVM_SIGNATURE_SHORT:
2420 case JVM_SIGNATURE_BOOLEAN:
2421
2422 // The remaining tag values are from Table 4.8 in the 2nd-edition of
2423 // the VM spec:
2424 case 's':
2425 {
2426 // For the above tag values (including the BaseType values),
2427 // value.const_value_index is right union field.
2428
2429 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2430 // not enough room for a const_value_index
2431 log_debug(redefine, class, annotation)("length() is too small for a const_value_index");
2432 return false;
2433 }
2434
2435 u2 const_value_index = rewrite_cp_ref_in_annotation_data(
2436 annotations_typeArray, byte_i_ref,
2437 "const_value_index");
2438
2439 log_debug(redefine, class, annotation)("const_value_index=%d", const_value_index);
2440 } break;
2441
2442 case 'e':
2443 {
2444 // for the above tag value, value.enum_const_value is right union field
2445
2446 if ((byte_i_ref + 4) > annotations_typeArray->length()) {
2447 // not enough room for a enum_const_value
2448 log_debug(redefine, class, annotation)("length() is too small for a enum_const_value");
2449 return false;
2450 }
2451
2452 u2 type_name_index = rewrite_cp_ref_in_annotation_data(
2453 annotations_typeArray, byte_i_ref,
2454 "type_name_index");
2455
2456 u2 const_name_index = rewrite_cp_ref_in_annotation_data(
2457 annotations_typeArray, byte_i_ref,
2458 "const_name_index");
2459
2460 log_debug(redefine, class, annotation)
2461 ("type_name_index=%d const_name_index=%d", type_name_index, const_name_index);
2462 } break;
2463
2464 case 'c':
2465 {
2466 // for the above tag value, value.class_info_index is right union field
2467
2468 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2469 // not enough room for a class_info_index
2470 log_debug(redefine, class, annotation)("length() is too small for a class_info_index");
2471 return false;
2472 }
2473
2474 u2 class_info_index = rewrite_cp_ref_in_annotation_data(
2475 annotations_typeArray, byte_i_ref,
2476 "class_info_index");
2477
2478 log_debug(redefine, class, annotation)("class_info_index=%d", class_info_index);
2479 } break;
2480
2481 case '@':
2482 // For the above tag value, value.attr_value is the right union
2483 // field. This is a nested annotation.
2484 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, byte_i_ref)) {
2485 // propagate failure back to caller
2486 return false;
2487 }
2488 break;
2489
2490 case JVM_SIGNATURE_ARRAY:
2491 {
2492 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2493 // not enough room for a num_values field
2494 log_debug(redefine, class, annotation)("length() is too small for a num_values field");
2495 return false;
2496 }
2497
2498 // For the above tag value, value.array_value is the right union
2499 // field. This is an array of nested element_value.
2500 u2 num_values = Bytes::get_Java_u2((address)
2501 annotations_typeArray->adr_at(byte_i_ref));
2502 byte_i_ref += 2;
2503 log_debug(redefine, class, annotation)("num_values=%d", num_values);
2504
2505 int calc_num_values = 0;
2506 for (; calc_num_values < num_values; calc_num_values++) {
2507 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, byte_i_ref)) {
2508 log_debug(redefine, class, annotation)("bad nested element_value at %d", calc_num_values);
2509 // propagate failure back to caller
2510 return false;
2511 }
2512 }
2513 assert(num_values == calc_num_values, "sanity check");
2514 } break;
2515
2516 default:
2517 log_debug(redefine, class, annotation)("bad tag=0x%x", tag);
2518 return false;
2519 } // end decode tag field
2520
2521 return true;
2522 } // end rewrite_cp_refs_in_element_value()
2523
2524
2525 // Rewrite constant pool references in a fields_annotations field.
2526 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations(
2527 InstanceKlass* scratch_class) {
2528
2529 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations();
2530
2531 if (fields_annotations == nullptr || fields_annotations->length() == 0) {
2532 // no fields_annotations so nothing to do
2533 return true;
2534 }
2535
2536 log_debug(redefine, class, annotation)("fields_annotations length=%d", fields_annotations->length());
2537
2538 for (int i = 0; i < fields_annotations->length(); i++) {
2539 AnnotationArray* field_annotations = fields_annotations->at(i);
2540 if (field_annotations == nullptr || field_annotations->length() == 0) {
2541 // this field does not have any annotations so skip it
2542 continue;
2543 }
2544
2545 int byte_i = 0; // byte index into field_annotations
2546 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i)) {
2547 log_debug(redefine, class, annotation)("bad field_annotations at %d", i);
2548 // propagate failure back to caller
2549 return false;
2550 }
2551 }
2552
2553 return true;
2554 } // end rewrite_cp_refs_in_fields_annotations()
2555
2556
2557 // Rewrite constant pool references in a methods_annotations field.
2558 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations(
2559 InstanceKlass* scratch_class) {
2560
2561 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2562 Method* m = scratch_class->methods()->at(i);
2563 AnnotationArray* method_annotations = m->constMethod()->method_annotations();
2564
2565 if (method_annotations == nullptr || method_annotations->length() == 0) {
2566 // this method does not have any annotations so skip it
2567 continue;
2568 }
2569
2570 int byte_i = 0; // byte index into method_annotations
2571 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i)) {
2572 log_debug(redefine, class, annotation)("bad method_annotations at %d", i);
2573 // propagate failure back to caller
2574 return false;
2575 }
2576 }
2577
2578 return true;
2579 } // end rewrite_cp_refs_in_methods_annotations()
2580
2581
2582 // Rewrite constant pool references in a methods_parameter_annotations
2583 // field. This "structure" is adapted from the
2584 // RuntimeVisibleParameterAnnotations_attribute described in section
2585 // 4.8.17 of the 2nd-edition of the VM spec:
2586 //
2587 // methods_parameter_annotations_typeArray {
2588 // u1 num_parameters;
2589 // {
2590 // u2 num_annotations;
2591 // annotation annotations[num_annotations];
2592 // } parameter_annotations[num_parameters];
2593 // }
2594 //
2595 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations(
2596 InstanceKlass* scratch_class) {
2597
2598 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2599 Method* m = scratch_class->methods()->at(i);
2600 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations();
2601 if (method_parameter_annotations == nullptr
2602 || method_parameter_annotations->length() == 0) {
2603 // this method does not have any parameter annotations so skip it
2604 continue;
2605 }
2606
2607 if (method_parameter_annotations->length() < 1) {
2608 // not enough room for a num_parameters field
2609 log_debug(redefine, class, annotation)("length() is too small for a num_parameters field at %d", i);
2610 return false;
2611 }
2612
2613 int byte_i = 0; // byte index into method_parameter_annotations
2614
2615 u1 num_parameters = method_parameter_annotations->at(byte_i);
2616 byte_i++;
2617
2618 log_debug(redefine, class, annotation)("num_parameters=%d", num_parameters);
2619
2620 int calc_num_parameters = 0;
2621 for (; calc_num_parameters < num_parameters; calc_num_parameters++) {
2622 if (!rewrite_cp_refs_in_annotations_typeArray(method_parameter_annotations, byte_i)) {
2623 log_debug(redefine, class, annotation)("bad method_parameter_annotations at %d", calc_num_parameters);
2624 // propagate failure back to caller
2625 return false;
2626 }
2627 }
2628 assert(num_parameters == calc_num_parameters, "sanity check");
2629 }
2630
2631 return true;
2632 } // end rewrite_cp_refs_in_methods_parameter_annotations()
2633
2634
2635 // Rewrite constant pool references in a methods_default_annotations
2636 // field. This "structure" is adapted from the AnnotationDefault_attribute
2637 // that is described in section 4.8.19 of the 2nd-edition of the VM spec:
2638 //
2639 // methods_default_annotations_typeArray {
2640 // element_value default_value;
2641 // }
2642 //
2643 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations(
2644 InstanceKlass* scratch_class) {
2645
2646 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2647 Method* m = scratch_class->methods()->at(i);
2648 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations();
2649 if (method_default_annotations == nullptr
2650 || method_default_annotations->length() == 0) {
2651 // this method does not have any default annotations so skip it
2652 continue;
2653 }
2654
2655 int byte_i = 0; // byte index into method_default_annotations
2656
2657 if (!rewrite_cp_refs_in_element_value(
2658 method_default_annotations, byte_i)) {
2659 log_debug(redefine, class, annotation)("bad default element_value at %d", i);
2660 // propagate failure back to caller
2661 return false;
2662 }
2663 }
2664
2665 return true;
2666 } // end rewrite_cp_refs_in_methods_default_annotations()
2667
2668
2669 // Rewrite constant pool references in a class_type_annotations field.
2670 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations(
2671 InstanceKlass* scratch_class) {
2672
2673 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations();
2674 if (class_type_annotations == nullptr || class_type_annotations->length() == 0) {
2675 // no class_type_annotations so nothing to do
2676 return true;
2677 }
2678
2679 log_debug(redefine, class, annotation)("class_type_annotations length=%d", class_type_annotations->length());
2680
2681 int byte_i = 0; // byte index into class_type_annotations
2682 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations,
2683 byte_i, "ClassFile");
2684 } // end rewrite_cp_refs_in_class_type_annotations()
2685
2686
2687 // Rewrite constant pool references in a fields_type_annotations field.
2688 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations(InstanceKlass* scratch_class) {
2689
2690 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations();
2691 if (fields_type_annotations == nullptr || fields_type_annotations->length() == 0) {
2692 // no fields_type_annotations so nothing to do
2693 return true;
2694 }
2695
2696 log_debug(redefine, class, annotation)("fields_type_annotations length=%d", fields_type_annotations->length());
2697
2698 for (int i = 0; i < fields_type_annotations->length(); i++) {
2699 AnnotationArray* field_type_annotations = fields_type_annotations->at(i);
2700 if (field_type_annotations == nullptr || field_type_annotations->length() == 0) {
2701 // this field does not have any annotations so skip it
2702 continue;
2703 }
2704
2705 int byte_i = 0; // byte index into field_type_annotations
2706 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations,
2707 byte_i, "field_info")) {
2708 log_debug(redefine, class, annotation)("bad field_type_annotations at %d", i);
2709 // propagate failure back to caller
2710 return false;
2711 }
2712 }
2713
2714 return true;
2715 } // end rewrite_cp_refs_in_fields_type_annotations()
2716
2717
2718 // Rewrite constant pool references in a methods_type_annotations field.
2719 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations(
2720 InstanceKlass* scratch_class) {
2721
2722 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2723 Method* m = scratch_class->methods()->at(i);
2724 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations();
2725
2726 if (method_type_annotations == nullptr || method_type_annotations->length() == 0) {
2727 // this method does not have any annotations so skip it
2728 continue;
2729 }
2730
2731 log_debug(redefine, class, annotation)("methods type_annotations length=%d", method_type_annotations->length());
2732
2733 int byte_i = 0; // byte index into method_type_annotations
2734 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations,
2735 byte_i, "method_info")) {
2736 log_debug(redefine, class, annotation)("bad method_type_annotations at %d", i);
2737 // propagate failure back to caller
2738 return false;
2739 }
2740 }
2741
2742 return true;
2743 } // end rewrite_cp_refs_in_methods_type_annotations()
2744
2745
2746 // Rewrite constant pool references in a type_annotations
2747 // field. This "structure" is adapted from the
2748 // RuntimeVisibleTypeAnnotations_attribute described in
2749 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2750 //
2751 // type_annotations_typeArray {
2752 // u2 num_annotations;
2753 // type_annotation annotations[num_annotations];
2754 // }
2755 //
2756 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray(
2757 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2758 const char * location_mesg) {
2759
2760 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2761 // not enough room for num_annotations field
2762 log_debug(redefine, class, annotation)("length() is too small for num_annotations field");
2763 return false;
2764 }
2765
2766 u2 num_annotations = Bytes::get_Java_u2((address)
2767 type_annotations_typeArray->adr_at(byte_i_ref));
2768 byte_i_ref += 2;
2769
2770 log_debug(redefine, class, annotation)("num_type_annotations=%d", num_annotations);
2771
2772 int calc_num_annotations = 0;
2773 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
2774 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray,
2775 byte_i_ref, location_mesg)) {
2776 log_debug(redefine, class, annotation)("bad type_annotation_struct at %d", calc_num_annotations);
2777 // propagate failure back to caller
2778 return false;
2779 }
2780 }
2781 assert(num_annotations == calc_num_annotations, "sanity check");
2782
2783 if (byte_i_ref != type_annotations_typeArray->length()) {
2784 log_debug(redefine, class, annotation)
2785 ("read wrong amount of bytes at end of processing type_annotations_typeArray (%d of %d bytes were read)",
2786 byte_i_ref, type_annotations_typeArray->length());
2787 return false;
2788 }
2789
2790 return true;
2791 } // end rewrite_cp_refs_in_type_annotations_typeArray()
2792
2793
2794 // Rewrite constant pool references in a type_annotation
2795 // field. This "structure" is adapted from the
2796 // RuntimeVisibleTypeAnnotations_attribute described in
2797 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2798 //
2799 // type_annotation {
2800 // u1 target_type;
2801 // union {
2802 // type_parameter_target;
2803 // supertype_target;
2804 // type_parameter_bound_target;
2805 // empty_target;
2806 // method_formal_parameter_target;
2807 // throws_target;
2808 // localvar_target;
2809 // catch_target;
2810 // offset_target;
2811 // type_argument_target;
2812 // } target_info;
2813 // type_path target_path;
2814 // annotation anno;
2815 // }
2816 //
2817 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct(
2818 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2819 const char * location_mesg) {
2820
2821 if (!skip_type_annotation_target(type_annotations_typeArray,
2822 byte_i_ref, location_mesg)) {
2823 return false;
2824 }
2825
2826 if (!skip_type_annotation_type_path(type_annotations_typeArray, byte_i_ref)) {
2827 return false;
2828 }
2829
2830 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray, byte_i_ref)) {
2831 return false;
2832 }
2833
2834 return true;
2835 } // end rewrite_cp_refs_in_type_annotation_struct()
2836
2837
2838 // Read, verify and skip over the target_type and target_info part
2839 // so that rewriting can continue in the later parts of the struct.
2840 //
2841 // u1 target_type;
2842 // union {
2843 // type_parameter_target;
2844 // supertype_target;
2845 // type_parameter_bound_target;
2846 // empty_target;
2847 // method_formal_parameter_target;
2848 // throws_target;
2849 // localvar_target;
2850 // catch_target;
2851 // offset_target;
2852 // type_argument_target;
2853 // } target_info;
2854 //
2855 bool VM_RedefineClasses::skip_type_annotation_target(
2856 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2857 const char * location_mesg) {
2858
2859 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2860 // not enough room for a target_type let alone the rest of a type_annotation
2861 log_debug(redefine, class, annotation)("length() is too small for a target_type");
2862 return false;
2863 }
2864
2865 u1 target_type = type_annotations_typeArray->at(byte_i_ref);
2866 byte_i_ref += 1;
2867 log_debug(redefine, class, annotation)("target_type=0x%.2x", target_type);
2868 log_debug(redefine, class, annotation)("location=%s", location_mesg);
2869
2870 // Skip over target_info
2871 switch (target_type) {
2872 case 0x00:
2873 // kind: type parameter declaration of generic class or interface
2874 // location: ClassFile
2875 case 0x01:
2876 // kind: type parameter declaration of generic method or constructor
2877 // location: method_info
2878
2879 {
2880 // struct:
2881 // type_parameter_target {
2882 // u1 type_parameter_index;
2883 // }
2884 //
2885 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2886 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_target");
2887 return false;
2888 }
2889
2890 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2891 byte_i_ref += 1;
2892
2893 log_debug(redefine, class, annotation)("type_parameter_target: type_parameter_index=%d", type_parameter_index);
2894 } break;
2895
2896 case 0x10:
2897 // kind: type in extends clause of class or interface declaration
2898 // or in implements clause of interface declaration
2899 // location: ClassFile
2900
2901 {
2902 // struct:
2903 // supertype_target {
2904 // u2 supertype_index;
2905 // }
2906 //
2907 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2908 log_debug(redefine, class, annotation)("length() is too small for a supertype_target");
2909 return false;
2910 }
2911
2912 u2 supertype_index = Bytes::get_Java_u2((address)
2913 type_annotations_typeArray->adr_at(byte_i_ref));
2914 byte_i_ref += 2;
2915
2916 log_debug(redefine, class, annotation)("supertype_target: supertype_index=%d", supertype_index);
2917 } break;
2918
2919 case 0x11:
2920 // kind: type in bound of type parameter declaration of generic class or interface
2921 // location: ClassFile
2922 case 0x12:
2923 // kind: type in bound of type parameter declaration of generic method or constructor
2924 // location: method_info
2925
2926 {
2927 // struct:
2928 // type_parameter_bound_target {
2929 // u1 type_parameter_index;
2930 // u1 bound_index;
2931 // }
2932 //
2933 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2934 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_bound_target");
2935 return false;
2936 }
2937
2938 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2939 byte_i_ref += 1;
2940 u1 bound_index = type_annotations_typeArray->at(byte_i_ref);
2941 byte_i_ref += 1;
2942
2943 log_debug(redefine, class, annotation)
2944 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d", type_parameter_index, bound_index);
2945 } break;
2946
2947 case 0x13:
2948 // kind: type in field declaration
2949 // location: field_info
2950 case 0x14:
2951 // kind: return type of method, or type of newly constructed object
2952 // location: method_info
2953 case 0x15:
2954 // kind: receiver type of method or constructor
2955 // location: method_info
2956
2957 {
2958 // struct:
2959 // empty_target {
2960 // }
2961 //
2962 log_debug(redefine, class, annotation)("empty_target");
2963 } break;
2964
2965 case 0x16:
2966 // kind: type in formal parameter declaration of method, constructor, or lambda expression
2967 // location: method_info
2968
2969 {
2970 // struct:
2971 // formal_parameter_target {
2972 // u1 formal_parameter_index;
2973 // }
2974 //
2975 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2976 log_debug(redefine, class, annotation)("length() is too small for a formal_parameter_target");
2977 return false;
2978 }
2979
2980 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2981 byte_i_ref += 1;
2982
2983 log_debug(redefine, class, annotation)
2984 ("formal_parameter_target: formal_parameter_index=%d", formal_parameter_index);
2985 } break;
2986
2987 case 0x17:
2988 // kind: type in throws clause of method or constructor
2989 // location: method_info
2990
2991 {
2992 // struct:
2993 // throws_target {
2994 // u2 throws_type_index
2995 // }
2996 //
2997 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2998 log_debug(redefine, class, annotation)("length() is too small for a throws_target");
2999 return false;
3000 }
3001
3002 u2 throws_type_index = Bytes::get_Java_u2((address)
3003 type_annotations_typeArray->adr_at(byte_i_ref));
3004 byte_i_ref += 2;
3005
3006 log_debug(redefine, class, annotation)("throws_target: throws_type_index=%d", throws_type_index);
3007 } break;
3008
3009 case 0x40:
3010 // kind: type in local variable declaration
3011 // location: Code
3012 case 0x41:
3013 // kind: type in resource variable declaration
3014 // location: Code
3015
3016 {
3017 // struct:
3018 // localvar_target {
3019 // u2 table_length;
3020 // struct {
3021 // u2 start_pc;
3022 // u2 length;
3023 // u2 index;
3024 // } table[table_length];
3025 // }
3026 //
3027 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
3028 // not enough room for a table_length let alone the rest of a localvar_target
3029 log_debug(redefine, class, annotation)("length() is too small for a localvar_target table_length");
3030 return false;
3031 }
3032
3033 u2 table_length = Bytes::get_Java_u2((address)
3034 type_annotations_typeArray->adr_at(byte_i_ref));
3035 byte_i_ref += 2;
3036
3037 log_debug(redefine, class, annotation)("localvar_target: table_length=%d", table_length);
3038
3039 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry
3040 int table_size = table_length * table_struct_size;
3041
3042 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) {
3043 // not enough room for a table
3044 log_debug(redefine, class, annotation)("length() is too small for a table array of length %d", table_length);
3045 return false;
3046 }
3047
3048 // Skip over table
3049 byte_i_ref += table_size;
3050 } break;
3051
3052 case 0x42:
3053 // kind: type in exception parameter declaration
3054 // location: Code
3055
3056 {
3057 // struct:
3058 // catch_target {
3059 // u2 exception_table_index;
3060 // }
3061 //
3062 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
3063 log_debug(redefine, class, annotation)("length() is too small for a catch_target");
3064 return false;
3065 }
3066
3067 u2 exception_table_index = Bytes::get_Java_u2((address)
3068 type_annotations_typeArray->adr_at(byte_i_ref));
3069 byte_i_ref += 2;
3070
3071 log_debug(redefine, class, annotation)("catch_target: exception_table_index=%d", exception_table_index);
3072 } break;
3073
3074 case 0x43:
3075 // kind: type in instanceof expression
3076 // location: Code
3077 case 0x44:
3078 // kind: type in new expression
3079 // location: Code
3080 case 0x45:
3081 // kind: type in method reference expression using ::new
3082 // location: Code
3083 case 0x46:
3084 // kind: type in method reference expression using ::Identifier
3085 // location: Code
3086
3087 {
3088 // struct:
3089 // offset_target {
3090 // u2 offset;
3091 // }
3092 //
3093 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
3094 log_debug(redefine, class, annotation)("length() is too small for a offset_target");
3095 return false;
3096 }
3097
3098 u2 offset = Bytes::get_Java_u2((address)
3099 type_annotations_typeArray->adr_at(byte_i_ref));
3100 byte_i_ref += 2;
3101
3102 log_debug(redefine, class, annotation)("offset_target: offset=%d", offset);
3103 } break;
3104
3105 case 0x47:
3106 // kind: type in cast expression
3107 // location: Code
3108 case 0x48:
3109 // kind: type argument for generic constructor in new expression or
3110 // explicit constructor invocation statement
3111 // location: Code
3112 case 0x49:
3113 // kind: type argument for generic method in method invocation expression
3114 // location: Code
3115 case 0x4A:
3116 // kind: type argument for generic constructor in method reference expression using ::new
3117 // location: Code
3118 case 0x4B:
3119 // kind: type argument for generic method in method reference expression using ::Identifier
3120 // location: Code
3121
3122 {
3123 // struct:
3124 // type_argument_target {
3125 // u2 offset;
3126 // u1 type_argument_index;
3127 // }
3128 //
3129 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) {
3130 log_debug(redefine, class, annotation)("length() is too small for a type_argument_target");
3131 return false;
3132 }
3133
3134 u2 offset = Bytes::get_Java_u2((address)
3135 type_annotations_typeArray->adr_at(byte_i_ref));
3136 byte_i_ref += 2;
3137 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
3138 byte_i_ref += 1;
3139
3140 log_debug(redefine, class, annotation)
3141 ("type_argument_target: offset=%d, type_argument_index=%d", offset, type_argument_index);
3142 } break;
3143
3144 default:
3145 log_debug(redefine, class, annotation)("unknown target_type");
3146 #ifdef ASSERT
3147 ShouldNotReachHere();
3148 #endif
3149 return false;
3150 }
3151
3152 return true;
3153 } // end skip_type_annotation_target()
3154
3155
3156 // Read, verify and skip over the type_path part so that rewriting
3157 // can continue in the later parts of the struct.
3158 //
3159 // type_path {
3160 // u1 path_length;
3161 // {
3162 // u1 type_path_kind;
3163 // u1 type_argument_index;
3164 // } path[path_length];
3165 // }
3166 //
3167 bool VM_RedefineClasses::skip_type_annotation_type_path(
3168 AnnotationArray* type_annotations_typeArray, int &byte_i_ref) {
3169
3170 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
3171 // not enough room for a path_length let alone the rest of the type_path
3172 log_debug(redefine, class, annotation)("length() is too small for a type_path");
3173 return false;
3174 }
3175
3176 u1 path_length = type_annotations_typeArray->at(byte_i_ref);
3177 byte_i_ref += 1;
3178
3179 log_debug(redefine, class, annotation)("type_path: path_length=%d", path_length);
3180
3181 int calc_path_length = 0;
3182 for (; calc_path_length < path_length; calc_path_length++) {
3183 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) {
3184 // not enough room for a path
3185 log_debug(redefine, class, annotation)
3186 ("length() is too small for path entry %d of %d", calc_path_length, path_length);
3187 return false;
3188 }
3189
3190 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref);
3191 byte_i_ref += 1;
3192 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
3193 byte_i_ref += 1;
3194
3195 log_debug(redefine, class, annotation)
3196 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d",
3197 calc_path_length, type_path_kind, type_argument_index);
3198
3199 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) {
3200 // not enough room for a path
3201 log_debug(redefine, class, annotation)("inconsistent type_path values");
3202 return false;
3203 }
3204 }
3205 assert(path_length == calc_path_length, "sanity check");
3206
3207 return true;
3208 } // end skip_type_annotation_type_path()
3209
3210
3211 // Rewrite constant pool references in the method's stackmap table.
3212 // These "structures" are adapted from the StackMapTable_attribute that
3213 // is described in section 4.8.4 of the 6.0 version of the VM spec
3214 // (dated 2005.10.26):
3215 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
3216 //
3217 // stack_map {
3218 // u2 number_of_entries;
3219 // stack_map_frame entries[number_of_entries];
3220 // }
3221 //
3222 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table(
3223 const methodHandle& method) {
3224
3225 if (!method->has_stackmap_table()) {
3226 return;
3227 }
3228
3229 AnnotationArray* stackmap_data = method->stackmap_data();
3230 address stackmap_p = (address)stackmap_data->adr_at(0);
3231 address stackmap_end = stackmap_p + stackmap_data->length();
3232
3233 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries");
3234 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p);
3235 stackmap_p += 2;
3236
3237 log_debug(redefine, class, stackmap)("number_of_entries=%u", number_of_entries);
3238
3239 // walk through each stack_map_frame
3240 u2 calc_number_of_entries = 0;
3241 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) {
3242 // The stack_map_frame structure is a u1 frame_type followed by
3243 // 0 or more bytes of data:
3244 //
3245 // union stack_map_frame {
3246 // same_frame;
3247 // same_locals_1_stack_item_frame;
3248 // same_locals_1_stack_item_frame_extended;
3249 // chop_frame;
3250 // same_frame_extended;
3251 // append_frame;
3252 // full_frame;
3253 // }
3254
3255 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type");
3256 u1 frame_type = *stackmap_p;
3257 stackmap_p++;
3258
3259 // same_frame {
3260 // u1 frame_type = SAME; /* 0-63 */
3261 // }
3262 if (frame_type <= StackMapReader::SAME_FRAME_END) {
3263 // nothing more to do for same_frame
3264 }
3265
3266 // same_locals_1_stack_item_frame {
3267 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */
3268 // verification_type_info stack[1];
3269 // }
3270 else if (frame_type >= StackMapReader::SAME_LOCALS_1_STACK_ITEM_FRAME_START &&
3271 frame_type <= StackMapReader::SAME_LOCALS_1_STACK_ITEM_FRAME_END) {
3272 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3273 calc_number_of_entries, frame_type);
3274 }
3275
3276 // reserved for future use
3277 else if (frame_type >= StackMapReader::RESERVED_START &&
3278 frame_type <= StackMapReader::RESERVED_END) {
3279 // nothing more to do for reserved frame_types
3280 }
3281
3282 // same_locals_1_stack_item_frame_extended {
3283 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */
3284 // u2 offset_delta;
3285 // verification_type_info stack[1];
3286 // }
3287 else if (frame_type == StackMapReader::SAME_LOCALS_1_STACK_ITEM_EXTENDED) {
3288 stackmap_p += 2;
3289 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3290 calc_number_of_entries, frame_type);
3291 }
3292
3293 // chop_frame {
3294 // u1 frame_type = CHOP; /* 248-250 */
3295 // u2 offset_delta;
3296 // }
3297 else if (frame_type >= StackMapReader::CHOP_FRAME_START &&
3298 frame_type <= StackMapReader::CHOP_FRAME_END) {
3299 stackmap_p += 2;
3300 }
3301
3302 // same_frame_extended {
3303 // u1 frame_type = SAME_EXTENDED; /* 251 */
3304 // u2 offset_delta;
3305 // }
3306 else if (frame_type == StackMapReader::SAME_FRAME_EXTENDED) {
3307 stackmap_p += 2;
3308 }
3309
3310 // append_frame {
3311 // u1 frame_type = APPEND; /* 252-254 */
3312 // u2 offset_delta;
3313 // verification_type_info locals[frame_type - SAME_EXTENDED];
3314 // }
3315 else if (frame_type >= StackMapReader::APPEND_FRAME_START &&
3316 frame_type <= StackMapReader::APPEND_FRAME_END) {
3317 assert(stackmap_p + 2 <= stackmap_end,
3318 "no room for offset_delta");
3319 stackmap_p += 2;
3320 u1 len = frame_type - StackMapReader::APPEND_FRAME_START + 1;
3321 for (u1 i = 0; i < len; i++) {
3322 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3323 calc_number_of_entries, frame_type);
3324 }
3325 }
3326
3327 // full_frame {
3328 // u1 frame_type = FULL_FRAME; /* 255 */
3329 // u2 offset_delta;
3330 // u2 number_of_locals;
3331 // verification_type_info locals[number_of_locals];
3332 // u2 number_of_stack_items;
3333 // verification_type_info stack[number_of_stack_items];
3334 // }
3335 else if (frame_type == StackMapReader::FULL_FRAME) {
3336 assert(stackmap_p + 2 + 2 <= stackmap_end,
3337 "no room for smallest full_frame");
3338 stackmap_p += 2;
3339
3340 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p);
3341 stackmap_p += 2;
3342
3343 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) {
3344 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3345 calc_number_of_entries, frame_type);
3346 }
3347
3348 // Use the largest size for the number_of_stack_items, but only get
3349 // the right number of bytes.
3350 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p);
3351 stackmap_p += 2;
3352
3353 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) {
3354 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3355 calc_number_of_entries, frame_type);
3356 }
3357 }
3358 } // end while there is a stack_map_frame
3359 assert(number_of_entries == calc_number_of_entries, "sanity check");
3360 } // end rewrite_cp_refs_in_stack_map_table()
3361
3362
3363 // Rewrite constant pool references in the verification type info
3364 // portion of the method's stackmap table. These "structures" are
3365 // adapted from the StackMapTable_attribute that is described in
3366 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26):
3367 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
3368 //
3369 // The verification_type_info structure is a u1 tag followed by 0 or
3370 // more bytes of data:
3371 //
3372 // union verification_type_info {
3373 // Top_variable_info;
3374 // Integer_variable_info;
3375 // Float_variable_info;
3376 // Long_variable_info;
3377 // Double_variable_info;
3378 // Null_variable_info;
3379 // UninitializedThis_variable_info;
3380 // Object_variable_info;
3381 // Uninitialized_variable_info;
3382 // }
3383 //
3384 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info(
3385 address& stackmap_p_ref, address stackmap_end, u2 frame_i,
3386 u1 frame_type) {
3387
3388 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag");
3389 u1 tag = *stackmap_p_ref;
3390 stackmap_p_ref++;
3391
3392 switch (tag) {
3393 // Top_variable_info {
3394 // u1 tag = ITEM_Top; /* 0 */
3395 // }
3396 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top
3397 case 0: // fall through
3398
3399 // Integer_variable_info {
3400 // u1 tag = ITEM_Integer; /* 1 */
3401 // }
3402 case ITEM_Integer: // fall through
3403
3404 // Float_variable_info {
3405 // u1 tag = ITEM_Float; /* 2 */
3406 // }
3407 case ITEM_Float: // fall through
3408
3409 // Double_variable_info {
3410 // u1 tag = ITEM_Double; /* 3 */
3411 // }
3412 case ITEM_Double: // fall through
3413
3414 // Long_variable_info {
3415 // u1 tag = ITEM_Long; /* 4 */
3416 // }
3417 case ITEM_Long: // fall through
3418
3419 // Null_variable_info {
3420 // u1 tag = ITEM_Null; /* 5 */
3421 // }
3422 case ITEM_Null: // fall through
3423
3424 // UninitializedThis_variable_info {
3425 // u1 tag = ITEM_UninitializedThis; /* 6 */
3426 // }
3427 case ITEM_UninitializedThis:
3428 // nothing more to do for the above tag types
3429 break;
3430
3431 // Object_variable_info {
3432 // u1 tag = ITEM_Object; /* 7 */
3433 // u2 cpool_index;
3434 // }
3435 case ITEM_Object:
3436 {
3437 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index");
3438 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref);
3439 u2 new_cp_index = find_new_index(cpool_index);
3440 if (new_cp_index != 0) {
3441 log_debug(redefine, class, stackmap)("mapped old cpool_index=%d", cpool_index);
3442 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
3443 cpool_index = new_cp_index;
3444 }
3445 stackmap_p_ref += 2;
3446
3447 log_debug(redefine, class, stackmap)
3448 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i, frame_type, cpool_index);
3449 } break;
3450
3451 // Uninitialized_variable_info {
3452 // u1 tag = ITEM_Uninitialized; /* 8 */
3453 // u2 offset;
3454 // }
3455 case ITEM_Uninitialized:
3456 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset");
3457 stackmap_p_ref += 2;
3458 break;
3459
3460 default:
3461 log_debug(redefine, class, stackmap)("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag);
3462 ShouldNotReachHere();
3463 break;
3464 } // end switch (tag)
3465 } // end rewrite_cp_refs_in_verification_type_info()
3466
3467
3468 // Change the constant pool associated with klass scratch_class to scratch_cp.
3469 // scratch_cp_length elements are copied from scratch_cp to a smaller constant pool
3470 // and the smaller constant pool is associated with scratch_class.
3471 void VM_RedefineClasses::set_new_constant_pool(
3472 ClassLoaderData* loader_data,
3473 InstanceKlass* scratch_class, constantPoolHandle scratch_cp,
3474 int scratch_cp_length, TRAPS) {
3475 assert(scratch_cp->length() >= scratch_cp_length, "sanity check");
3476
3477 // scratch_cp is a merged constant pool and has enough space for a
3478 // worst case merge situation. We want to associate the minimum
3479 // sized constant pool with the klass to save space.
3480 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK);
3481 constantPoolHandle smaller_cp(THREAD, cp);
3482
3483 // preserve version() value in the smaller copy
3484 int version = scratch_cp->version();
3485 assert(version != 0, "sanity check");
3486 smaller_cp->set_version(version);
3487
3488 // attach klass to new constant pool
3489 // reference to the cp holder is needed for reallocating the BSM attribute
3490 smaller_cp->set_pool_holder(scratch_class);
3491
3492 smaller_cp->copy_fields(scratch_cp());
3493
3494 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
3495 if (HAS_PENDING_EXCEPTION) {
3496 // Exception is handled in the caller
3497 loader_data->add_to_deallocate_list(smaller_cp());
3498 return;
3499 }
3500 scratch_cp = smaller_cp;
3501
3502 // attach new constant pool to klass
3503 scratch_class->set_constants(scratch_cp());
3504 scratch_cp->initialize_unresolved_klasses(loader_data, CHECK);
3505
3506 int i; // for portability
3507
3508 // update each field in klass to use new constant pool indices as needed
3509 int java_fields;
3510 int injected_fields;
3511 bool update_required = false;
3512 GrowableArray<FieldInfo>* fields = FieldInfoStream::create_FieldInfoArray(scratch_class->fieldinfo_stream(), &java_fields, &injected_fields);
3513 for (int i = 0; i < java_fields; i++) {
3514 FieldInfo* fi = fields->adr_at(i);
3515 jshort cur_index = fi->name_index();
3516 jshort new_index = find_new_index(cur_index);
3517 if (new_index != 0) {
3518 log_trace(redefine, class, constantpool)("field-name_index change: %d to %d", cur_index, new_index);
3519 fi->set_name_index(new_index);
3520 update_required = true;
3521 }
3522 cur_index = fi->signature_index();
3523 new_index = find_new_index(cur_index);
3524 if (new_index != 0) {
3525 log_trace(redefine, class, constantpool)("field-signature_index change: %d to %d", cur_index, new_index);
3526 fi->set_signature_index(new_index);
3527 update_required = true;
3528 }
3529 cur_index = fi->initializer_index();
3530 new_index = find_new_index(cur_index);
3531 if (new_index != 0) {
3532 log_trace(redefine, class, constantpool)("field-initval_index change: %d to %d", cur_index, new_index);
3533 fi->set_initializer_index(new_index);
3534 update_required = true;
3535 }
3536 cur_index = fi->generic_signature_index();
3537 new_index = find_new_index(cur_index);
3538 if (new_index != 0) {
3539 log_trace(redefine, class, constantpool)("field-generic_signature change: %d to %d", cur_index, new_index);
3540 fi->set_generic_signature_index(new_index);
3541 update_required = true;
3542 }
3543 }
3544 if (update_required) {
3545 Array<u1>* old_stream = scratch_class->fieldinfo_stream();
3546 assert(fields->length() == (java_fields + injected_fields), "Must be");
3547 Array<u1>* new_fis = FieldInfoStream::create_FieldInfoStream(fields, java_fields, injected_fields, scratch_class->class_loader_data(), CHECK);
3548 scratch_class->set_fieldinfo_stream(new_fis);
3549 MetadataFactory::free_array<u1>(scratch_class->class_loader_data(), old_stream);
3550
3551 Array<u1>* old_table = scratch_class->fieldinfo_search_table();
3552 Array<u1>* search_table = FieldInfoStream::create_search_table(scratch_class->constants(), new_fis, scratch_class->class_loader_data(), CHECK);
3553 scratch_class->set_fieldinfo_search_table(search_table);
3554 MetadataFactory::free_array<u1>(scratch_class->class_loader_data(), old_table);
3555
3556 DEBUG_ONLY(FieldInfoStream::validate_search_table(scratch_class->constants(), new_fis, search_table));
3557 }
3558
3559 // Update constant pool indices in the inner classes info to use
3560 // new constant indices as needed. The inner classes info is a
3561 // quadruple:
3562 // (inner_class_info, outer_class_info, inner_name, inner_access_flags)
3563 InnerClassesIterator iter(scratch_class);
3564 for (; !iter.done(); iter.next()) {
3565 int cur_index = iter.inner_class_info_index();
3566 if (cur_index == 0) {
3567 continue; // JVM spec. allows null inner class refs so skip it
3568 }
3569 u2 new_index = find_new_index(cur_index);
3570 if (new_index != 0) {
3571 log_trace(redefine, class, constantpool)("inner_class_info change: %d to %d", cur_index, new_index);
3572 iter.set_inner_class_info_index(new_index);
3573 }
3574 cur_index = iter.outer_class_info_index();
3575 new_index = find_new_index(cur_index);
3576 if (new_index != 0) {
3577 log_trace(redefine, class, constantpool)("outer_class_info change: %d to %d", cur_index, new_index);
3578 iter.set_outer_class_info_index(new_index);
3579 }
3580 cur_index = iter.inner_name_index();
3581 new_index = find_new_index(cur_index);
3582 if (new_index != 0) {
3583 log_trace(redefine, class, constantpool)("inner_name change: %d to %d", cur_index, new_index);
3584 iter.set_inner_name_index(new_index);
3585 }
3586 } // end for each inner class
3587
3588 // Attach each method in klass to the new constant pool and update
3589 // to use new constant pool indices as needed:
3590 Array<Method*>* methods = scratch_class->methods();
3591 for (i = methods->length() - 1; i >= 0; i--) {
3592 methodHandle method(THREAD, methods->at(i));
3593 method->set_constants(scratch_cp());
3594
3595 u2 new_index = find_new_index(method->name_index());
3596 if (new_index != 0) {
3597 log_trace(redefine, class, constantpool)
3598 ("method-name_index change: %d to %d", method->name_index(), new_index);
3599 method->set_name_index(new_index);
3600 }
3601 new_index = find_new_index(method->signature_index());
3602 if (new_index != 0) {
3603 log_trace(redefine, class, constantpool)
3604 ("method-signature_index change: %d to %d", method->signature_index(), new_index);
3605 method->set_signature_index(new_index);
3606 }
3607 new_index = find_new_index(method->generic_signature_index());
3608 if (new_index != 0) {
3609 log_trace(redefine, class, constantpool)
3610 ("method-generic_signature_index change: %d to %d", method->generic_signature_index(), new_index);
3611 method->constMethod()->set_generic_signature_index(new_index);
3612 }
3613
3614 // Update constant pool indices in the method's checked exception
3615 // table to use new constant indices as needed.
3616 int cext_length = method->checked_exceptions_length();
3617 if (cext_length > 0) {
3618 CheckedExceptionElement * cext_table =
3619 method->checked_exceptions_start();
3620 for (int j = 0; j < cext_length; j++) {
3621 int cur_index = cext_table[j].class_cp_index;
3622 int new_index = find_new_index(cur_index);
3623 if (new_index != 0) {
3624 log_trace(redefine, class, constantpool)("cext-class_cp_index change: %d to %d", cur_index, new_index);
3625 cext_table[j].class_cp_index = (u2)new_index;
3626 }
3627 } // end for each checked exception table entry
3628 } // end if there are checked exception table entries
3629
3630 // Update each catch type index in the method's exception table
3631 // to use new constant pool indices as needed. The exception table
3632 // holds quadruple entries of the form:
3633 // (beg_bci, end_bci, handler_bci, klass_index)
3634
3635 ExceptionTable ex_table(method());
3636 int ext_length = ex_table.length();
3637
3638 for (int j = 0; j < ext_length; j ++) {
3639 int cur_index = ex_table.catch_type_index(j);
3640 u2 new_index = find_new_index(cur_index);
3641 if (new_index != 0) {
3642 log_trace(redefine, class, constantpool)("ext-klass_index change: %d to %d", cur_index, new_index);
3643 ex_table.set_catch_type_index(j, new_index);
3644 }
3645 } // end for each exception table entry
3646
3647 // Update constant pool indices in the method's local variable
3648 // table to use new constant indices as needed. The local variable
3649 // table hold sextuple entries of the form:
3650 // (start_pc, length, name_index, descriptor_index, signature_index, slot)
3651 int lvt_length = method->localvariable_table_length();
3652 if (lvt_length > 0) {
3653 LocalVariableTableElement * lv_table =
3654 method->localvariable_table_start();
3655 for (int j = 0; j < lvt_length; j++) {
3656 int cur_index = lv_table[j].name_cp_index;
3657 int new_index = find_new_index(cur_index);
3658 if (new_index != 0) {
3659 log_trace(redefine, class, constantpool)("lvt-name_cp_index change: %d to %d", cur_index, new_index);
3660 lv_table[j].name_cp_index = (u2)new_index;
3661 }
3662 cur_index = lv_table[j].descriptor_cp_index;
3663 new_index = find_new_index(cur_index);
3664 if (new_index != 0) {
3665 log_trace(redefine, class, constantpool)("lvt-descriptor_cp_index change: %d to %d", cur_index, new_index);
3666 lv_table[j].descriptor_cp_index = (u2)new_index;
3667 }
3668 cur_index = lv_table[j].signature_cp_index;
3669 new_index = find_new_index(cur_index);
3670 if (new_index != 0) {
3671 log_trace(redefine, class, constantpool)("lvt-signature_cp_index change: %d to %d", cur_index, new_index);
3672 lv_table[j].signature_cp_index = (u2)new_index;
3673 }
3674 } // end for each local variable table entry
3675 } // end if there are local variable table entries
3676
3677 // Update constant pool indices in the method's method_parameters.
3678 int mp_length = method->method_parameters_length();
3679 if (mp_length > 0) {
3680 MethodParametersElement* elem = method->method_parameters_start();
3681 for (int j = 0; j < mp_length; j++) {
3682 const int cp_index = elem[j].name_cp_index;
3683 const int new_cp_index = find_new_index(cp_index);
3684 if (new_cp_index != 0) {
3685 elem[j].name_cp_index = (u2)new_cp_index;
3686 }
3687 }
3688 }
3689
3690 rewrite_cp_refs_in_stack_map_table(method);
3691 } // end for each method
3692 } // end set_new_constant_pool()
3693
3694
3695 // Unevolving classes may point to methods of the_class directly
3696 // from their constant pool caches, itables, and/or vtables. We
3697 // use the ClassLoaderDataGraph::classes_do() facility and this helper
3698 // to fix up these pointers. MethodData also points to old methods and
3699 // must be cleaned.
3700
3701 // Adjust cpools and vtables closure
3702 void VM_RedefineClasses::AdjustAndCleanMetadata::do_klass(Klass* k) {
3703
3704 // This is a very busy routine. We don't want too much tracing
3705 // printed out.
3706 bool trace_name_printed = false;
3707
3708 // If the class being redefined is java.lang.Object, we need to fix all
3709 // array class vtables also. The _has_redefined_Object flag is global.
3710 // Once the java.lang.Object has been redefined (by the current or one
3711 // of the previous VM_RedefineClasses operations) we have to always
3712 // adjust method entries for array classes.
3713 if (k->is_array_klass() && _has_redefined_Object) {
3714 k->vtable().adjust_method_entries(&trace_name_printed);
3715
3716 } else if (k->is_instance_klass()) {
3717 HandleMark hm(_thread);
3718 InstanceKlass *ik = InstanceKlass::cast(k);
3719
3720 // Clean MethodData of this class's methods so they don't refer to
3721 // old methods that are no longer running.
3722 Array<Method*>* methods = ik->methods();
3723 int num_methods = methods->length();
3724 for (int index = 0; index < num_methods; ++index) {
3725 if (methods->at(index)->method_data() != nullptr) {
3726 methods->at(index)->method_data()->clean_weak_method_links();
3727 }
3728 }
3729
3730 // Adjust all vtables, default methods and itables, to clean out old methods.
3731 ResourceMark rm(_thread);
3732 if (ik->vtable_length() > 0) {
3733 ik->vtable().adjust_method_entries(&trace_name_printed);
3734 ik->adjust_default_methods(&trace_name_printed);
3735 }
3736
3737 if (ik->itable_length() > 0) {
3738 ik->itable().adjust_method_entries(&trace_name_printed);
3739 }
3740
3741 // The constant pools in other classes (other_cp) can refer to
3742 // old methods. We have to update method information in
3743 // other_cp's cache. If other_cp has a previous version, then we
3744 // have to repeat the process for each previous version. The
3745 // constant pool cache holds the Method*s for non-virtual
3746 // methods and for virtual, final methods.
3747 //
3748 // Special case: if the current class is being redefined by the current
3749 // VM_RedefineClasses operation, then new_cp has already been attached
3750 // to the_class and old_cp has already been added as a previous version.
3751 // The new_cp doesn't have any cached references to old methods so it
3752 // doesn't need to be updated and we could optimize by skipping it.
3753 // However, the current class can be marked as being redefined by another
3754 // VM_RedefineClasses operation which has already executed its doit_prologue
3755 // and needs cpcache method entries adjusted. For simplicity, the cpcache
3756 // update is done unconditionally. It should result in doing nothing for
3757 // classes being redefined by the current VM_RedefineClasses operation.
3758 // Method entries in the previous version(s) are adjusted as well.
3759 ConstantPoolCache* cp_cache;
3760
3761 // this klass' constant pool cache may need adjustment
3762 ConstantPool* other_cp = ik->constants();
3763 cp_cache = other_cp->cache();
3764 if (cp_cache != nullptr) {
3765 cp_cache->adjust_method_entries(&trace_name_printed);
3766 }
3767
3768 // the previous versions' constant pool caches may need adjustment
3769 for (InstanceKlass* pv_node = ik->previous_versions();
3770 pv_node != nullptr;
3771 pv_node = pv_node->previous_versions()) {
3772 cp_cache = pv_node->constants()->cache();
3773 if (cp_cache != nullptr) {
3774 cp_cache->adjust_method_entries(&trace_name_printed);
3775 }
3776 }
3777 }
3778 }
3779
3780 void VM_RedefineClasses::update_jmethod_ids() {
3781 for (int j = 0; j < _matching_methods_length; ++j) {
3782 Method* old_method = _matching_old_methods[j];
3783 // The method_idnum should be within the range of 1..number-of-methods
3784 // until incremented later for obsolete methods.
3785 // The increment is so if a jmethodID is created for an old obsolete method
3786 // it gets a new jmethodID cache slot in the InstanceKlass.
3787 // They're cleaned out later when all methods of the previous version are purged.
3788 assert(old_method->method_idnum() <= _old_methods->length(),
3789 "shouldn't be incremented yet for obsolete methods");
3790 jmethodID jmid = old_method->find_jmethod_id_or_null();
3791 if (jmid != nullptr) {
3792 // There is a jmethodID, change it to point to the new method
3793 Method* new_method = _matching_new_methods[j];
3794 Method::change_method_associated_with_jmethod_id(jmid, new_method);
3795 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j],
3796 "should be replaced");
3797 }
3798 }
3799 }
3800
3801 int VM_RedefineClasses::check_methods_and_mark_as_obsolete() {
3802 int emcp_method_count = 0;
3803 int obsolete_count = 0;
3804 int old_index = 0;
3805 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
3806 Method* old_method = _matching_old_methods[j];
3807 Method* new_method = _matching_new_methods[j];
3808 Method* old_array_method;
3809
3810 // Maintain an old_index into the _old_methods array by skipping
3811 // deleted methods
3812 while ((old_array_method = _old_methods->at(old_index)) != old_method) {
3813 ++old_index;
3814 }
3815
3816 if (MethodComparator::methods_EMCP(old_method, new_method)) {
3817 // The EMCP definition from JSR-163 requires the bytecodes to be
3818 // the same with the exception of constant pool indices which may
3819 // differ. However, the constants referred to by those indices
3820 // must be the same.
3821 //
3822 // We use methods_EMCP() for comparison since constant pool
3823 // merging can remove duplicate constant pool entries that were
3824 // present in the old method and removed from the rewritten new
3825 // method. A faster binary comparison function would consider the
3826 // old and new methods to be different when they are actually
3827 // EMCP.
3828 //
3829 // The old and new methods are EMCP and you would think that we
3830 // could get rid of one of them here and now and save some space.
3831 // However, the concept of EMCP only considers the bytecodes and
3832 // the constant pool entries in the comparison. Other things,
3833 // e.g., the line number table (LNT) or the local variable table
3834 // (LVT) don't count in the comparison. So the new (and EMCP)
3835 // method can have a new LNT that we need so we can't just
3836 // overwrite the new method with the old method.
3837 //
3838 // When this routine is called, we have already attached the new
3839 // methods to the_class so the old methods are effectively
3840 // overwritten. However, if an old method is still executing,
3841 // then the old method cannot be collected until sometime after
3842 // the old method call has returned. So the overwriting of old
3843 // methods by new methods will save us space except for those
3844 // (hopefully few) old methods that are still executing.
3845 //
3846 // A method refers to a ConstMethod* and this presents another
3847 // possible avenue to space savings. The ConstMethod* in the
3848 // new method contains possibly new attributes (LNT, LVT, etc).
3849 // At first glance, it seems possible to save space by replacing
3850 // the ConstMethod* in the old method with the ConstMethod*
3851 // from the new method. The old and new methods would share the
3852 // same ConstMethod* and we would save the space occupied by
3853 // the old ConstMethod*. However, the ConstMethod* contains
3854 // a back reference to the containing method. Sharing the
3855 // ConstMethod* between two methods could lead to confusion in
3856 // the code that uses the back reference. This would lead to
3857 // brittle code that could be broken in non-obvious ways now or
3858 // in the future.
3859 //
3860 // Another possibility is to copy the ConstMethod* from the new
3861 // method to the old method and then overwrite the new method with
3862 // the old method. Since the ConstMethod* contains the bytecodes
3863 // for the method embedded in the oop, this option would change
3864 // the bytecodes out from under any threads executing the old
3865 // method and make the thread's bcp invalid. Since EMCP requires
3866 // that the bytecodes be the same modulo constant pool indices, it
3867 // is straight forward to compute the correct new bcp in the new
3868 // ConstMethod* from the old bcp in the old ConstMethod*. The
3869 // time consuming part would be searching all the frames in all
3870 // of the threads to find all of the calls to the old method.
3871 //
3872 // It looks like we will have to live with the limited savings
3873 // that we get from effectively overwriting the old methods
3874 // when the new methods are attached to the_class.
3875
3876 // Count number of methods that are EMCP. The method will be marked
3877 // old but not obsolete if it is EMCP.
3878 emcp_method_count++;
3879
3880 // An EMCP method is _not_ obsolete. An obsolete method has a
3881 // different jmethodID than the current method. An EMCP method
3882 // has the same jmethodID as the current method. Having the
3883 // same jmethodID for all EMCP versions of a method allows for
3884 // a consistent view of the EMCP methods regardless of which
3885 // EMCP method you happen to have in hand. For example, a
3886 // breakpoint set in one EMCP method will work for all EMCP
3887 // versions of the method including the current one.
3888 } else {
3889 // mark obsolete methods as such
3890 old_method->set_is_obsolete();
3891 obsolete_count++;
3892
3893 // obsolete methods need a unique idnum so they become new entries in
3894 // the jmethodID cache in InstanceKlass
3895 assert(old_method->method_idnum() == new_method->method_idnum(), "must match");
3896 u2 num = InstanceKlass::cast(_the_class)->next_method_idnum();
3897 if (num != ConstMethod::UNSET_IDNUM) {
3898 old_method->set_method_idnum(num);
3899 }
3900
3901 // With tracing we try not to "yack" too much. The position of
3902 // this trace assumes there are fewer obsolete methods than
3903 // EMCP methods.
3904 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) {
3905 ResourceMark rm;
3906 log_trace(redefine, class, obsolete, mark)
3907 ("mark %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string());
3908 }
3909 }
3910 old_method->set_is_old();
3911 }
3912 for (int i = 0; i < _deleted_methods_length; ++i) {
3913 Method* old_method = _deleted_methods[i];
3914
3915 assert(!old_method->has_vtable_index(),
3916 "cannot delete methods with vtable entries");;
3917
3918 // Mark all deleted methods as old, obsolete and deleted
3919 old_method->set_is_deleted();
3920 old_method->set_is_old();
3921 old_method->set_is_obsolete();
3922 ++obsolete_count;
3923 // With tracing we try not to "yack" too much. The position of
3924 // this trace assumes there are fewer obsolete methods than
3925 // EMCP methods.
3926 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) {
3927 ResourceMark rm;
3928 log_trace(redefine, class, obsolete, mark)
3929 ("mark deleted %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string());
3930 }
3931 }
3932 assert((emcp_method_count + obsolete_count) == _old_methods->length(),
3933 "sanity check");
3934 log_trace(redefine, class, obsolete, mark)("EMCP_cnt=%d, obsolete_cnt=%d", emcp_method_count, obsolete_count);
3935 return emcp_method_count;
3936 }
3937
3938 // This internal class transfers the native function registration from old methods
3939 // to new methods. It is designed to handle both the simple case of unchanged
3940 // native methods and the complex cases of native method prefixes being added and/or
3941 // removed.
3942 // It expects only to be used during the VM_RedefineClasses op (a safepoint).
3943 //
3944 // This class is used after the new methods have been installed in "the_class".
3945 //
3946 // So, for example, the following must be handled. Where 'm' is a method and
3947 // a number followed by an underscore is a prefix.
3948 //
3949 // Old Name New Name
3950 // Simple transfer to new method m -> m
3951 // Add prefix m -> 1_m
3952 // Remove prefix 1_m -> m
3953 // Simultaneous add of prefixes m -> 3_2_1_m
3954 // Simultaneous removal of prefixes 3_2_1_m -> m
3955 // Simultaneous add and remove 1_m -> 2_m
3956 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m
3957 //
3958 class TransferNativeFunctionRegistration {
3959 private:
3960 InstanceKlass* the_class;
3961 int prefix_count;
3962 char** prefixes;
3963
3964 // Recursively search the binary tree of possibly prefixed method names.
3965 // Iteration could be used if all agents were well behaved. Full tree walk is
3966 // more resilent to agents not cleaning up intermediate methods.
3967 // Branch at each depth in the binary tree is:
3968 // (1) without the prefix.
3969 // (2) with the prefix.
3970 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
3971 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len,
3972 Symbol* signature) {
3973 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len);
3974 if (name_symbol != nullptr) {
3975 Method* method = the_class->lookup_method(name_symbol, signature);
3976 if (method != nullptr) {
3977 // Even if prefixed, intermediate methods must exist.
3978 if (method->is_native()) {
3979 // Wahoo, we found a (possibly prefixed) version of the method, return it.
3980 return method;
3981 }
3982 if (depth < prefix_count) {
3983 // Try applying further prefixes (other than this one).
3984 method = search_prefix_name_space(depth+1, name_str, name_len, signature);
3985 if (method != nullptr) {
3986 return method; // found
3987 }
3988
3989 // Try adding this prefix to the method name and see if it matches
3990 // another method name.
3991 char* prefix = prefixes[depth];
3992 size_t prefix_len = strlen(prefix);
3993 size_t trial_len = name_len + prefix_len;
3994 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
3995 strcpy(trial_name_str, prefix);
3996 strcat(trial_name_str, name_str);
3997 method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
3998 signature);
3999 if (method != nullptr) {
4000 // If found along this branch, it was prefixed, mark as such
4001 method->set_is_prefixed_native();
4002 return method; // found
4003 }
4004 }
4005 }
4006 }
4007 return nullptr; // This whole branch bore nothing
4008 }
4009
4010 // Return the method name with old prefixes stripped away.
4011 char* method_name_without_prefixes(Method* method) {
4012 Symbol* name = method->name();
4013 char* name_str = name->as_utf8();
4014
4015 // Old prefixing may be defunct, strip prefixes, if any.
4016 for (int i = prefix_count-1; i >= 0; i--) {
4017 char* prefix = prefixes[i];
4018 size_t prefix_len = strlen(prefix);
4019 if (strncmp(prefix, name_str, prefix_len) == 0) {
4020 name_str += prefix_len;
4021 }
4022 }
4023 return name_str;
4024 }
4025
4026 // Strip any prefixes off the old native method, then try to find a
4027 // (possibly prefixed) new native that matches it.
4028 Method* strip_and_search_for_new_native(Method* method) {
4029 ResourceMark rm;
4030 char* name_str = method_name_without_prefixes(method);
4031 return search_prefix_name_space(0, name_str, strlen(name_str),
4032 method->signature());
4033 }
4034
4035 public:
4036
4037 // Construct a native method transfer processor for this class.
4038 TransferNativeFunctionRegistration(InstanceKlass* _the_class) {
4039 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
4040
4041 the_class = _the_class;
4042 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
4043 }
4044
4045 // Attempt to transfer any of the old or deleted methods that are native
4046 void transfer_registrations(Method** old_methods, int methods_length) {
4047 for (int j = 0; j < methods_length; j++) {
4048 Method* old_method = old_methods[j];
4049
4050 if (old_method->is_native() && old_method->has_native_function()) {
4051 Method* new_method = strip_and_search_for_new_native(old_method);
4052 if (new_method != nullptr) {
4053 // Actually set the native function in the new method.
4054 // Redefine does not send events (except CFLH), certainly not this
4055 // behind the scenes re-registration.
4056 new_method->set_native_function(old_method->native_function(),
4057 !Method::native_bind_event_is_interesting);
4058 }
4059 }
4060 }
4061 }
4062 };
4063
4064 // Don't lose the association between a native method and its JNI function.
4065 void VM_RedefineClasses::transfer_old_native_function_registrations(InstanceKlass* the_class) {
4066 TransferNativeFunctionRegistration transfer(the_class);
4067 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length);
4068 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length);
4069 }
4070
4071 // Deoptimize all compiled code that depends on the classes redefined.
4072 //
4073 // If the can_redefine_classes capability is obtained in the onload
4074 // phase or 'AlwaysRecordEvolDependencies' is true, then the compiler has
4075 // recorded all dependencies from startup. In that case we need only
4076 // deoptimize and throw away all compiled code that depends on the class.
4077 //
4078 // If can_redefine_classes is obtained sometime after the onload phase
4079 // (and 'AlwaysRecordEvolDependencies' is false) then the dependency
4080 // information may be incomplete. In that case the first call to
4081 // RedefineClasses causes all compiled code to be thrown away. As
4082 // can_redefine_classes has been obtained then all future compilations will
4083 // record dependencies so second and subsequent calls to RedefineClasses
4084 // need only throw away code that depends on the class.
4085 //
4086
4087 void VM_RedefineClasses::flush_dependent_code() {
4088 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
4089 assert(JvmtiExport::all_dependencies_are_recorded() || !AlwaysRecordEvolDependencies, "sanity check");
4090
4091 DeoptimizationScope deopt_scope;
4092
4093 // This is the first redefinition, mark all the nmethods for deoptimization
4094 if (!JvmtiExport::all_dependencies_are_recorded()) {
4095 CodeCache::mark_all_nmethods_for_evol_deoptimization(&deopt_scope);
4096 log_debug(redefine, class, nmethod)("Marked all nmethods for deopt");
4097 } else {
4098 CodeCache::mark_dependents_for_evol_deoptimization(&deopt_scope);
4099 log_debug(redefine, class, nmethod)("Marked dependent nmethods for deopt");
4100 }
4101
4102 deopt_scope.deoptimize_marked();
4103
4104 // From now on we know that the dependency information is complete
4105 JvmtiExport::set_all_dependencies_are_recorded(true);
4106 }
4107
4108 void VM_RedefineClasses::compute_added_deleted_matching_methods() {
4109 Method* old_method;
4110 Method* new_method;
4111
4112 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
4113 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
4114 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length());
4115 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
4116
4117 _matching_methods_length = 0;
4118 _deleted_methods_length = 0;
4119 _added_methods_length = 0;
4120
4121 int nj = 0;
4122 int oj = 0;
4123 while (true) {
4124 if (oj >= _old_methods->length()) {
4125 if (nj >= _new_methods->length()) {
4126 break; // we've looked at everything, done
4127 }
4128 // New method at the end
4129 new_method = _new_methods->at(nj);
4130 _added_methods[_added_methods_length++] = new_method;
4131 ++nj;
4132 } else if (nj >= _new_methods->length()) {
4133 // Old method, at the end, is deleted
4134 old_method = _old_methods->at(oj);
4135 _deleted_methods[_deleted_methods_length++] = old_method;
4136 ++oj;
4137 } else {
4138 old_method = _old_methods->at(oj);
4139 new_method = _new_methods->at(nj);
4140 if (old_method->name() == new_method->name()) {
4141 if (old_method->signature() == new_method->signature()) {
4142 _matching_old_methods[_matching_methods_length ] = old_method;
4143 _matching_new_methods[_matching_methods_length++] = new_method;
4144 ++nj;
4145 ++oj;
4146 } else {
4147 // added overloaded have already been moved to the end,
4148 // so this is a deleted overloaded method
4149 _deleted_methods[_deleted_methods_length++] = old_method;
4150 ++oj;
4151 }
4152 } else { // names don't match
4153 if (old_method->name()->fast_compare(new_method->name()) > 0) {
4154 // new method
4155 _added_methods[_added_methods_length++] = new_method;
4156 ++nj;
4157 } else {
4158 // deleted method
4159 _deleted_methods[_deleted_methods_length++] = old_method;
4160 ++oj;
4161 }
4162 }
4163 }
4164 }
4165 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
4166 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
4167 }
4168
4169
4170 void VM_RedefineClasses::swap_annotations(InstanceKlass* the_class,
4171 InstanceKlass* scratch_class) {
4172 // Swap annotation fields values
4173 Annotations* old_annotations = the_class->annotations();
4174 the_class->set_annotations(scratch_class->annotations());
4175 scratch_class->set_annotations(old_annotations);
4176 }
4177
4178
4179 // Install the redefinition of a class:
4180 // - house keeping (flushing breakpoints and caches, deoptimizing
4181 // dependent compiled code)
4182 // - replacing parts in the_class with parts from scratch_class
4183 // - adding a weak reference to track the obsolete but interesting
4184 // parts of the_class
4185 // - adjusting constant pool caches and vtables in other classes
4186 // that refer to methods in the_class. These adjustments use the
4187 // ClassLoaderDataGraph::classes_do() facility which only allows
4188 // a helper method to be specified. The interesting parameters
4189 // that we would like to pass to the helper method are saved in
4190 // static global fields in the VM operation.
4191 void VM_RedefineClasses::redefine_single_class(Thread* current, jclass the_jclass,
4192 InstanceKlass* scratch_class) {
4193
4194 HandleMark hm(current); // make sure handles from this call are freed
4195
4196 if (log_is_enabled(Info, redefine, class, timer)) {
4197 _timer_rsc_phase1.start();
4198 }
4199
4200 InstanceKlass* the_class = get_ik(the_jclass);
4201
4202 // Set a flag to control and optimize adjusting method entries
4203 _has_redefined_Object |= the_class == vmClasses::Object_klass();
4204
4205 // Remove all breakpoints in methods of this class
4206 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
4207 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class);
4208
4209 _old_methods = the_class->methods();
4210 _new_methods = scratch_class->methods();
4211 _the_class = the_class;
4212 compute_added_deleted_matching_methods();
4213 update_jmethod_ids();
4214
4215 _any_class_has_resolved_methods = the_class->has_resolved_methods() || _any_class_has_resolved_methods;
4216
4217 // Attach new constant pool to the original klass. The original
4218 // klass still refers to the old constant pool (for now).
4219 scratch_class->constants()->set_pool_holder(the_class);
4220
4221 #if 0
4222 // In theory, with constant pool merging in place we should be able
4223 // to save space by using the new, merged constant pool in place of
4224 // the old constant pool(s). By "pool(s)" I mean the constant pool in
4225 // the klass version we are replacing now and any constant pool(s) in
4226 // previous versions of klass. Nice theory, doesn't work in practice.
4227 // When this code is enabled, even simple programs throw NullPointer
4228 // exceptions. I'm guessing that this is caused by some constant pool
4229 // cache difference between the new, merged constant pool and the
4230 // constant pool that was just being used by the klass. I'm keeping
4231 // this code around to archive the idea, but the code has to remain
4232 // disabled for now.
4233
4234 // Attach each old method to the new constant pool. This can be
4235 // done here since we are past the bytecode verification and
4236 // constant pool optimization phases.
4237 for (int i = _old_methods->length() - 1; i >= 0; i--) {
4238 Method* method = _old_methods->at(i);
4239 method->set_constants(scratch_class->constants());
4240 }
4241
4242 // NOTE: this doesn't work because you can redefine the same class in two
4243 // threads, each getting their own constant pool data appended to the
4244 // original constant pool. In order for the new methods to work when they
4245 // become old methods, they need to keep their updated copy of the constant pool.
4246
4247 {
4248 // walk all previous versions of the klass
4249 InstanceKlass *ik = the_class;
4250 PreviousVersionWalker pvw(ik);
4251 do {
4252 ik = pvw.next_previous_version();
4253 if (ik != nullptr) {
4254
4255 // attach previous version of klass to the new constant pool
4256 ik->set_constants(scratch_class->constants());
4257
4258 // Attach each method in the previous version of klass to the
4259 // new constant pool
4260 Array<Method*>* prev_methods = ik->methods();
4261 for (int i = prev_methods->length() - 1; i >= 0; i--) {
4262 Method* method = prev_methods->at(i);
4263 method->set_constants(scratch_class->constants());
4264 }
4265 }
4266 } while (ik != nullptr);
4267 }
4268 #endif
4269
4270 // Replace methods and constantpool
4271 the_class->set_methods(_new_methods);
4272 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods,
4273 // and to be able to undo operation easily.
4274
4275 Array<int>* old_ordering = the_class->method_ordering();
4276 the_class->set_method_ordering(scratch_class->method_ordering());
4277 scratch_class->set_method_ordering(old_ordering);
4278
4279 ConstantPool* old_constants = the_class->constants();
4280 the_class->set_constants(scratch_class->constants());
4281 scratch_class->set_constants(old_constants); // See the previous comment.
4282 #if 0
4283 // We are swapping the guts of "the new class" with the guts of "the
4284 // class". Since the old constant pool has just been attached to "the
4285 // new class", it seems logical to set the pool holder in the old
4286 // constant pool also. However, doing this will change the observable
4287 // class hierarchy for any old methods that are still executing. A
4288 // method can query the identity of its "holder" and this query uses
4289 // the method's constant pool link to find the holder. The change in
4290 // holding class from "the class" to "the new class" can confuse
4291 // things.
4292 //
4293 // Setting the old constant pool's holder will also cause
4294 // verification done during vtable initialization below to fail.
4295 // During vtable initialization, the vtable's class is verified to be
4296 // a subtype of the method's holder. The vtable's class is "the
4297 // class" and the method's holder is gotten from the constant pool
4298 // link in the method itself. For "the class"'s directly implemented
4299 // methods, the method holder is "the class" itself (as gotten from
4300 // the new constant pool). The check works fine in this case. The
4301 // check also works fine for methods inherited from super classes.
4302 //
4303 // Miranda methods are a little more complicated. A miranda method is
4304 // provided by an interface when the class implementing the interface
4305 // does not provide its own method. These interfaces are implemented
4306 // internally as an InstanceKlass. These special instanceKlasses
4307 // share the constant pool of the class that "implements" the
4308 // interface. By sharing the constant pool, the method holder of a
4309 // miranda method is the class that "implements" the interface. In a
4310 // non-redefine situation, the subtype check works fine. However, if
4311 // the old constant pool's pool holder is modified, then the check
4312 // fails because there is no class hierarchy relationship between the
4313 // vtable's class and "the new class".
4314
4315 old_constants->set_pool_holder(scratch_class());
4316 #endif
4317
4318 // track number of methods that are EMCP for add_previous_version() call below
4319 int emcp_method_count = check_methods_and_mark_as_obsolete();
4320 transfer_old_native_function_registrations(the_class);
4321
4322 if (scratch_class->get_cached_class_file() != the_class->get_cached_class_file()) {
4323 // 1. the_class doesn't have a cache yet, scratch_class does have a cache.
4324 // 2. The same class can be present twice in the scratch classes list or there
4325 // are multiple concurrent RetransformClasses calls on different threads.
4326 // the_class and scratch_class have the same cached bytes, but different buffers.
4327 // In such cases we need to deallocate one of the buffers.
4328 // 3. RedefineClasses and the_class has cached bytes from a previous transformation.
4329 // In the case we need to use class bytes from scratch_class.
4330 if (the_class->get_cached_class_file() != nullptr) {
4331 os::free(the_class->get_cached_class_file());
4332 }
4333 the_class->set_cached_class_file(scratch_class->get_cached_class_file());
4334 }
4335
4336 // null out in scratch class to not delete twice. The class to be redefined
4337 // always owns these bytes.
4338 scratch_class->set_cached_class_file(nullptr);
4339
4340 // Replace inner_classes
4341 Array<u2>* old_inner_classes = the_class->inner_classes();
4342 the_class->set_inner_classes(scratch_class->inner_classes());
4343 scratch_class->set_inner_classes(old_inner_classes);
4344
4345 // Initialize the vtable and interface table after
4346 // methods have been rewritten
4347 // no exception should happen here since we explicitly
4348 // do not check loader constraints.
4349 // compare_and_normalize_class_versions has already checked:
4350 // - classloaders unchanged, signatures unchanged
4351 // - all instanceKlasses for redefined classes reused & contents updated
4352 the_class->vtable().initialize_vtable();
4353 the_class->itable().initialize_itable();
4354
4355 // Update jmethodID cache if present.
4356 the_class->update_methods_jmethod_cache();
4357
4358 // Copy the "source debug extension" attribute from new class version
4359 the_class->set_source_debug_extension(
4360 scratch_class->source_debug_extension(),
4361 scratch_class->source_debug_extension() == nullptr ? 0 :
4362 (int)strlen(scratch_class->source_debug_extension()));
4363
4364 // Use of javac -g could be different in the old and the new
4365 if (scratch_class->has_localvariable_table() !=
4366 the_class->has_localvariable_table()) {
4367 the_class->set_has_localvariable_table(scratch_class->has_localvariable_table());
4368 }
4369
4370 swap_annotations(the_class, scratch_class);
4371
4372 // Replace minor version number of class file
4373 u2 old_minor_version = the_class->constants()->minor_version();
4374 the_class->constants()->set_minor_version(scratch_class->constants()->minor_version());
4375 scratch_class->constants()->set_minor_version(old_minor_version);
4376
4377 // Replace major version number of class file
4378 u2 old_major_version = the_class->constants()->major_version();
4379 the_class->constants()->set_major_version(scratch_class->constants()->major_version());
4380 scratch_class->constants()->set_major_version(old_major_version);
4381
4382 // Replace CP indexes for class and name+type of enclosing method
4383 u2 old_class_idx = the_class->enclosing_method_class_index();
4384 u2 old_method_idx = the_class->enclosing_method_method_index();
4385 the_class->set_enclosing_method_indices(
4386 scratch_class->enclosing_method_class_index(),
4387 scratch_class->enclosing_method_method_index());
4388 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx);
4389
4390 if (!the_class->has_been_redefined()) {
4391 the_class->set_has_been_redefined();
4392 }
4393
4394 // Scratch class is unloaded but still needs cleaning, and skipping for CDS.
4395 scratch_class->set_is_scratch_class();
4396
4397 // keep track of previous versions of this class
4398 the_class->add_previous_version(scratch_class, emcp_method_count);
4399
4400 JFR_ONLY(Jfr::on_klass_redefinition(the_class, scratch_class);)
4401
4402 _timer_rsc_phase1.stop();
4403 if (log_is_enabled(Info, redefine, class, timer)) {
4404 _timer_rsc_phase2.start();
4405 }
4406
4407 if (the_class->oop_map_cache() != nullptr) {
4408 // Flush references to any obsolete methods from the oop map cache
4409 // so that obsolete methods are not pinned.
4410 the_class->oop_map_cache()->flush_obsolete_entries();
4411 }
4412
4413 increment_class_counter(the_class);
4414
4415 if (EventClassRedefinition::is_enabled()) {
4416 EventClassRedefinition event;
4417 event.set_classModificationCount(java_lang_Class::classRedefinedCount(the_class->java_mirror()));
4418 event.set_redefinedClass(the_class);
4419 event.set_redefinitionId(_id);
4420 event.commit();
4421 }
4422
4423 {
4424 ResourceMark rm(current);
4425 // increment the classRedefinedCount field in the_class and in any
4426 // direct and indirect subclasses of the_class
4427 physical_memory_size_type avail_mem = 0;
4428 // Return value ignored - defaulting to 0 on failure.
4429 (void)os::available_memory(avail_mem);
4430 log_info(redefine, class, load)
4431 ("redefined name=%s, count=%d (avail_mem=" PHYS_MEM_TYPE_FORMAT "K)",
4432 the_class->external_name(), java_lang_Class::classRedefinedCount(the_class->java_mirror()), avail_mem >> 10);
4433 Events::log_redefinition(current, "redefined class name=%s, count=%d",
4434 the_class->external_name(),
4435 java_lang_Class::classRedefinedCount(the_class->java_mirror()));
4436
4437 }
4438 _timer_rsc_phase2.stop();
4439
4440 } // end redefine_single_class()
4441
4442
4443 // Increment the classRedefinedCount field in the specific InstanceKlass
4444 // and in all direct and indirect subclasses.
4445 void VM_RedefineClasses::increment_class_counter(InstanceKlass* ik) {
4446 for (ClassHierarchyIterator iter(ik); !iter.done(); iter.next()) {
4447 // Only update instanceKlasses
4448 Klass* sub = iter.klass();
4449 if (sub->is_instance_klass()) {
4450 oop class_mirror = InstanceKlass::cast(sub)->java_mirror();
4451 Klass* class_oop = java_lang_Class::as_Klass(class_mirror);
4452 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
4453 java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
4454
4455 if (class_oop != _the_class) {
4456 // _the_class count is printed at end of redefine_single_class()
4457 log_debug(redefine, class, subclass)("updated count in subclass=%s to %d", ik->external_name(), new_count);
4458 }
4459 }
4460 }
4461 }
4462
4463 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) {
4464 bool no_old_methods = true; // be optimistic
4465
4466 // Both array and instance classes have vtables.
4467 // a vtable should never contain old or obsolete methods
4468 ResourceMark rm(_thread);
4469 if (k->vtable_length() > 0 &&
4470 !k->vtable().check_no_old_or_obsolete_entries()) {
4471 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4472 log_trace(redefine, class, obsolete, metadata)
4473 ("klassVtable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4474 k->signature_name());
4475 k->vtable().dump_vtable();
4476 }
4477 no_old_methods = false;
4478 }
4479
4480 if (k->is_instance_klass()) {
4481 HandleMark hm(_thread);
4482 InstanceKlass *ik = InstanceKlass::cast(k);
4483
4484 // an itable should never contain old or obsolete methods
4485 if (ik->itable_length() > 0 &&
4486 !ik->itable().check_no_old_or_obsolete_entries()) {
4487 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4488 log_trace(redefine, class, obsolete, metadata)
4489 ("klassItable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4490 ik->signature_name());
4491 ik->itable().dump_itable();
4492 }
4493 no_old_methods = false;
4494 }
4495
4496 // the constant pool cache should never contain non-deleted old or obsolete methods
4497 if (ik->constants() != nullptr &&
4498 ik->constants()->cache() != nullptr &&
4499 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) {
4500 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4501 log_trace(redefine, class, obsolete, metadata)
4502 ("cp-cache::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4503 ik->signature_name());
4504 ik->constants()->cache()->dump_cache();
4505 }
4506 no_old_methods = false;
4507 }
4508 }
4509
4510 // print and fail guarantee if old methods are found.
4511 if (!no_old_methods) {
4512 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4513 dump_methods();
4514 } else {
4515 log_trace(redefine, class)("Use the '-Xlog:redefine+class*:' option "
4516 "to see more info about the following guarantee() failure.");
4517 }
4518 guarantee(false, "OLD and/or OBSOLETE method(s) found");
4519 }
4520 }
4521
4522 u8 VM_RedefineClasses::next_id() {
4523 while (true) {
4524 u8 id = _id_counter;
4525 u8 next_id = id + 1;
4526 u8 result = AtomicAccess::cmpxchg(&_id_counter, id, next_id);
4527 if (result == id) {
4528 return next_id;
4529 }
4530 }
4531 }
4532
4533 void VM_RedefineClasses::dump_methods() {
4534 int j;
4535 log_trace(redefine, class, dump)("_old_methods --");
4536 for (j = 0; j < _old_methods->length(); ++j) {
4537 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4538 Method* m = _old_methods->at(j);
4539 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4540 m->access_flags().print_on(&log_stream);
4541 log_stream.print(" -- ");
4542 m->print_name(&log_stream);
4543 log_stream.cr();
4544 }
4545 log_trace(redefine, class, dump)("_new_methods --");
4546 for (j = 0; j < _new_methods->length(); ++j) {
4547 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4548 Method* m = _new_methods->at(j);
4549 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4550 m->access_flags().print_on(&log_stream);
4551 log_stream.print(" -- ");
4552 m->print_name(&log_stream);
4553 log_stream.cr();
4554 }
4555 log_trace(redefine, class, dump)("_matching_methods --");
4556 for (j = 0; j < _matching_methods_length; ++j) {
4557 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4558 Method* m = _matching_old_methods[j];
4559 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4560 m->access_flags().print_on(&log_stream);
4561 log_stream.print(" -- ");
4562 m->print_name();
4563 log_stream.cr();
4564
4565 m = _matching_new_methods[j];
4566 log_stream.print(" (%5d) ", m->vtable_index());
4567 m->access_flags().print_on(&log_stream);
4568 log_stream.cr();
4569 }
4570 log_trace(redefine, class, dump)("_deleted_methods --");
4571 for (j = 0; j < _deleted_methods_length; ++j) {
4572 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4573 Method* m = _deleted_methods[j];
4574 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4575 m->access_flags().print_on(&log_stream);
4576 log_stream.print(" -- ");
4577 m->print_name(&log_stream);
4578 log_stream.cr();
4579 }
4580 log_trace(redefine, class, dump)("_added_methods --");
4581 for (j = 0; j < _added_methods_length; ++j) {
4582 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4583 Method* m = _added_methods[j];
4584 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4585 m->access_flags().print_on(&log_stream);
4586 log_stream.print(" -- ");
4587 m->print_name(&log_stream);
4588 log_stream.cr();
4589 }
4590 }
4591
4592 void VM_RedefineClasses::print_on_error(outputStream* st) const {
4593 VM_Operation::print_on_error(st);
4594 if (_the_class != nullptr) {
4595 ResourceMark rm;
4596 st->print_cr(", redefining class %s", _the_class->external_name());
4597 }
4598 }