1 /*
2 * Copyright (c) 2003, 2023, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "cds/metaspaceShared.hpp"
27 #include "classfile/classFileStream.hpp"
28 #include "classfile/classLoaderDataGraph.hpp"
29 #include "classfile/classLoadInfo.hpp"
30 #include "classfile/javaClasses.inline.hpp"
31 #include "classfile/metadataOnStackMark.hpp"
32 #include "classfile/symbolTable.hpp"
33 #include "classfile/klassFactory.hpp"
34 #include "classfile/verifier.hpp"
35 #include "classfile/vmClasses.hpp"
36 #include "classfile/vmSymbols.hpp"
37 #include "code/codeCache.hpp"
38 #include "compiler/compileBroker.hpp"
39 #include "interpreter/oopMapCache.hpp"
40 #include "interpreter/rewriter.hpp"
41 #include "jfr/jfrEvents.hpp"
42 #include "logging/logStream.hpp"
43 #include "memory/metadataFactory.hpp"
44 #include "memory/resourceArea.hpp"
45 #include "memory/universe.hpp"
46 #include "oops/annotations.hpp"
47 #include "oops/constantPool.hpp"
48 #include "oops/fieldStreams.inline.hpp"
49 #include "oops/klass.inline.hpp"
50 #include "oops/klassVtable.hpp"
51 #include "oops/oop.inline.hpp"
52 #include "oops/recordComponent.hpp"
53 #include "prims/jvmtiImpl.hpp"
54 #include "prims/jvmtiRedefineClasses.hpp"
55 #include "prims/jvmtiThreadState.inline.hpp"
56 #include "prims/resolvedMethodTable.hpp"
57 #include "prims/methodComparator.hpp"
58 #include "runtime/atomic.hpp"
59 #include "runtime/deoptimization.hpp"
60 #include "runtime/handles.inline.hpp"
61 #include "runtime/jniHandles.inline.hpp"
62 #include "runtime/relocator.hpp"
63 #include "runtime/safepointVerifiers.hpp"
64 #include "utilities/bitMap.inline.hpp"
65 #include "utilities/events.hpp"
66
67 Array<Method*>* VM_RedefineClasses::_old_methods = nullptr;
68 Array<Method*>* VM_RedefineClasses::_new_methods = nullptr;
69 Method** VM_RedefineClasses::_matching_old_methods = nullptr;
70 Method** VM_RedefineClasses::_matching_new_methods = nullptr;
71 Method** VM_RedefineClasses::_deleted_methods = nullptr;
72 Method** VM_RedefineClasses::_added_methods = nullptr;
73 int VM_RedefineClasses::_matching_methods_length = 0;
74 int VM_RedefineClasses::_deleted_methods_length = 0;
75 int VM_RedefineClasses::_added_methods_length = 0;
76
77 // This flag is global as the constructor does not reset it:
78 bool VM_RedefineClasses::_has_redefined_Object = false;
79 u8 VM_RedefineClasses::_id_counter = 0;
80
81 VM_RedefineClasses::VM_RedefineClasses(jint class_count,
82 const jvmtiClassDefinition *class_defs,
83 JvmtiClassLoadKind class_load_kind) {
84 _class_count = class_count;
85 _class_defs = class_defs;
86 _class_load_kind = class_load_kind;
87 _any_class_has_resolved_methods = false;
88 _res = JVMTI_ERROR_NONE;
89 _the_class = nullptr;
90 _id = next_id();
91 }
92
93 static inline InstanceKlass* get_ik(jclass def) {
94 oop mirror = JNIHandles::resolve_non_null(def);
95 return InstanceKlass::cast(java_lang_Class::as_Klass(mirror));
96 }
97
98 // If any of the classes are being redefined, wait
99 // Parallel constant pool merging leads to indeterminate constant pools.
100 void VM_RedefineClasses::lock_classes() {
101 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
102 GrowableArray<Klass*>* redef_classes = state->get_classes_being_redefined();
103
104 MonitorLocker ml(RedefineClasses_lock);
105
106 if (redef_classes == nullptr) {
107 redef_classes = new (mtClass) GrowableArray<Klass*>(1, mtClass);
108 state->set_classes_being_redefined(redef_classes);
109 }
110
111 bool has_redefined;
112 do {
113 has_redefined = false;
114 // Go through classes each time until none are being redefined. Skip
115 // the ones that are being redefined by this thread currently. Class file
116 // load hook event may trigger new class redefine when we are redefining
117 // a class (after lock_classes()).
118 for (int i = 0; i < _class_count; i++) {
119 InstanceKlass* ik = get_ik(_class_defs[i].klass);
120 // Check if we are currently redefining the class in this thread already.
121 if (redef_classes->contains(ik)) {
122 assert(ik->is_being_redefined(), "sanity");
123 } else {
124 if (ik->is_being_redefined()) {
125 ml.wait();
126 has_redefined = true;
127 break; // for loop
128 }
129 }
130 }
131 } while (has_redefined);
132
133 for (int i = 0; i < _class_count; i++) {
134 InstanceKlass* ik = get_ik(_class_defs[i].klass);
135 redef_classes->push(ik); // Add to the _classes_being_redefined list
136 ik->set_is_being_redefined(true);
137 }
138 ml.notify_all();
139 }
140
141 void VM_RedefineClasses::unlock_classes() {
142 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
143 GrowableArray<Klass*>* redef_classes = state->get_classes_being_redefined();
144 assert(redef_classes != nullptr, "_classes_being_redefined is not allocated");
145
146 MonitorLocker ml(RedefineClasses_lock);
147
148 for (int i = _class_count - 1; i >= 0; i--) {
149 InstanceKlass* def_ik = get_ik(_class_defs[i].klass);
150 if (redef_classes->length() > 0) {
151 // Remove the class from _classes_being_redefined list
152 Klass* k = redef_classes->pop();
153 assert(def_ik == k, "unlocking wrong class");
154 }
155 assert(def_ik->is_being_redefined(),
156 "should be being redefined to get here");
157
158 // Unlock after we finish all redefines for this class within
159 // the thread. Same class can be pushed to the list multiple
160 // times (not more than once by each recursive redefinition).
161 if (!redef_classes->contains(def_ik)) {
162 def_ik->set_is_being_redefined(false);
163 }
164 }
165 ml.notify_all();
166 }
167
168 bool VM_RedefineClasses::doit_prologue() {
169 if (_class_count == 0) {
170 _res = JVMTI_ERROR_NONE;
171 return false;
172 }
173 if (_class_defs == nullptr) {
174 _res = JVMTI_ERROR_NULL_POINTER;
175 return false;
176 }
177
178 for (int i = 0; i < _class_count; i++) {
179 if (_class_defs[i].klass == nullptr) {
180 _res = JVMTI_ERROR_INVALID_CLASS;
181 return false;
182 }
183 if (_class_defs[i].class_byte_count == 0) {
184 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT;
185 return false;
186 }
187 if (_class_defs[i].class_bytes == nullptr) {
188 _res = JVMTI_ERROR_NULL_POINTER;
189 return false;
190 }
191
192 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass);
193 // classes for primitives, arrays, and hidden classes
194 // cannot be redefined.
195 if (!is_modifiable_class(mirror)) {
196 _res = JVMTI_ERROR_UNMODIFIABLE_CLASS;
197 return false;
198 }
199 }
200
201 // Start timer after all the sanity checks; not quite accurate, but
202 // better than adding a bunch of stop() calls.
203 if (log_is_enabled(Info, redefine, class, timer)) {
204 _timer_vm_op_prologue.start();
205 }
206
207 lock_classes();
208 // We first load new class versions in the prologue, because somewhere down the
209 // call chain it is required that the current thread is a Java thread.
210 _res = load_new_class_versions();
211 if (_res != JVMTI_ERROR_NONE) {
212 // free any successfully created classes, since none are redefined
213 for (int i = 0; i < _class_count; i++) {
214 if (_scratch_classes[i] != nullptr) {
215 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data();
216 // Free the memory for this class at class unloading time. Not before
217 // because CMS might think this is still live.
218 InstanceKlass* ik = get_ik(_class_defs[i].klass);
219 if (ik->get_cached_class_file() == _scratch_classes[i]->get_cached_class_file()) {
220 // Don't double-free cached_class_file copied from the original class if error.
221 _scratch_classes[i]->set_cached_class_file(nullptr);
222 }
223 cld->add_to_deallocate_list(InstanceKlass::cast(_scratch_classes[i]));
224 }
225 }
226 // Free os::malloc allocated memory in load_new_class_version.
227 os::free(_scratch_classes);
228 _timer_vm_op_prologue.stop();
229 unlock_classes();
230 return false;
231 }
232
233 _timer_vm_op_prologue.stop();
234 return true;
235 }
236
237 void VM_RedefineClasses::doit() {
238 Thread* current = Thread::current();
239
240 if (log_is_enabled(Info, redefine, class, timer)) {
241 _timer_vm_op_doit.start();
242 }
243
244 #if INCLUDE_CDS
245 if (UseSharedSpaces) {
246 // Sharing is enabled so we remap the shared readonly space to
247 // shared readwrite, private just in case we need to redefine
248 // a shared class. We do the remap during the doit() phase of
249 // the safepoint to be safer.
250 if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) {
251 log_info(redefine, class, load)("failed to remap shared readonly space to readwrite, private");
252 _res = JVMTI_ERROR_INTERNAL;
253 _timer_vm_op_doit.stop();
254 return;
255 }
256 }
257 #endif
258
259 // Mark methods seen on stack and everywhere else so old methods are not
260 // cleaned up if they're on the stack.
261 MetadataOnStackMark md_on_stack(/*walk_all_metadata*/true, /*redefinition_walk*/true);
262 HandleMark hm(current); // make sure any handles created are deleted
263 // before the stack walk again.
264
265 for (int i = 0; i < _class_count; i++) {
266 redefine_single_class(current, _class_defs[i].klass, _scratch_classes[i]);
267 }
268
269 // Flush all compiled code that depends on the classes redefined.
270 flush_dependent_code();
271
272 // Adjust constantpool caches and vtables for all classes
273 // that reference methods of the evolved classes.
274 // Have to do this after all classes are redefined and all methods that
275 // are redefined are marked as old.
276 AdjustAndCleanMetadata adjust_and_clean_metadata(current);
277 ClassLoaderDataGraph::classes_do(&adjust_and_clean_metadata);
278
279 // JSR-292 support
280 if (_any_class_has_resolved_methods) {
281 bool trace_name_printed = false;
282 ResolvedMethodTable::adjust_method_entries(&trace_name_printed);
283 }
284
285 // Increment flag indicating that some invariants are no longer true.
286 // See jvmtiExport.hpp for detailed explanation.
287 JvmtiExport::increment_redefinition_count();
288
289 // check_class() is optionally called for product bits, but is
290 // always called for non-product bits.
291 #ifdef PRODUCT
292 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
293 #endif
294 log_trace(redefine, class, obsolete, metadata)("calling check_class");
295 CheckClass check_class(current);
296 ClassLoaderDataGraph::classes_do(&check_class);
297 #ifdef PRODUCT
298 }
299 #endif
300
301 // Clean up any metadata now unreferenced while MetadataOnStackMark is set.
302 ClassLoaderDataGraph::clean_deallocate_lists(false);
303
304 _timer_vm_op_doit.stop();
305 }
306
307 void VM_RedefineClasses::doit_epilogue() {
308 unlock_classes();
309
310 // Free os::malloc allocated memory.
311 os::free(_scratch_classes);
312
313 // Reset the_class to null for error printing.
314 _the_class = nullptr;
315
316 if (log_is_enabled(Info, redefine, class, timer)) {
317 // Used to have separate timers for "doit" and "all", but the timer
318 // overhead skewed the measurements.
319 julong doit_time = _timer_vm_op_doit.milliseconds();
320 julong all_time = _timer_vm_op_prologue.milliseconds() + doit_time;
321
322 log_info(redefine, class, timer)
323 ("vm_op: all=" JULONG_FORMAT " prologue=" JULONG_FORMAT " doit=" JULONG_FORMAT,
324 all_time, (julong)_timer_vm_op_prologue.milliseconds(), doit_time);
325 log_info(redefine, class, timer)
326 ("redefine_single_class: phase1=" JULONG_FORMAT " phase2=" JULONG_FORMAT,
327 (julong)_timer_rsc_phase1.milliseconds(), (julong)_timer_rsc_phase2.milliseconds());
328 }
329 }
330
331 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) {
332 // classes for primitives cannot be redefined
333 if (java_lang_Class::is_primitive(klass_mirror)) {
334 return false;
335 }
336 Klass* k = java_lang_Class::as_Klass(klass_mirror);
337 // classes for arrays cannot be redefined
338 if (k == nullptr || !k->is_instance_klass()) {
339 return false;
340 }
341
342 // Cannot redefine or retransform a hidden class.
343 if (InstanceKlass::cast(k)->is_hidden()) {
344 return false;
345 }
346 if (InstanceKlass::cast(k) == vmClasses::Continuation_klass()) {
347 // Don't redefine Continuation class. See 8302779.
348 return false;
349 }
350 return true;
351 }
352
353 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p
354 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For
355 // direct CP entries, there is just the current entry to append. For
356 // indirect and double-indirect CP entries, there are zero or more
357 // referenced CP entries along with the current entry to append.
358 // Indirect and double-indirect CP entries are handled by recursive
359 // calls to append_entry() as needed. The referenced CP entries are
360 // always appended to *merge_cp_p before the referee CP entry. These
361 // referenced CP entries may already exist in *merge_cp_p in which case
362 // there is nothing extra to append and only the current entry is
363 // appended.
364 void VM_RedefineClasses::append_entry(const constantPoolHandle& scratch_cp,
365 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) {
366
367 // append is different depending on entry tag type
368 switch (scratch_cp->tag_at(scratch_i).value()) {
369
370 // The old verifier is implemented outside the VM. It loads classes,
371 // but does not resolve constant pool entries directly so we never
372 // see Class entries here with the old verifier. Similarly the old
373 // verifier does not like Class entries in the input constant pool.
374 // The split-verifier is implemented in the VM so it can optionally
375 // and directly resolve constant pool entries to load classes. The
376 // split-verifier can accept either Class entries or UnresolvedClass
377 // entries in the input constant pool. We revert the appended copy
378 // back to UnresolvedClass so that either verifier will be happy
379 // with the constant pool entry.
380 //
381 // this is an indirect CP entry so it needs special handling
382 case JVM_CONSTANT_Class:
383 case JVM_CONSTANT_UnresolvedClass:
384 {
385 int name_i = scratch_cp->klass_name_index_at(scratch_i);
386 int new_name_i = find_or_append_indirect_entry(scratch_cp, name_i, merge_cp_p,
387 merge_cp_length_p);
388
389 if (new_name_i != name_i) {
390 log_trace(redefine, class, constantpool)
391 ("Class entry@%d name_index change: %d to %d",
392 *merge_cp_length_p, name_i, new_name_i);
393 }
394
395 (*merge_cp_p)->temp_unresolved_klass_at_put(*merge_cp_length_p, new_name_i);
396 if (scratch_i != *merge_cp_length_p) {
397 // The new entry in *merge_cp_p is at a different index than
398 // the new entry in scratch_cp so we need to map the index values.
399 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
400 }
401 (*merge_cp_length_p)++;
402 } break;
403
404 // these are direct CP entries so they can be directly appended,
405 // but double and long take two constant pool entries
406 case JVM_CONSTANT_Double: // fall through
407 case JVM_CONSTANT_Long:
408 {
409 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p);
410
411 if (scratch_i != *merge_cp_length_p) {
412 // The new entry in *merge_cp_p is at a different index than
413 // the new entry in scratch_cp so we need to map the index values.
414 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
415 }
416 (*merge_cp_length_p) += 2;
417 } break;
418
419 // these are direct CP entries so they can be directly appended
420 case JVM_CONSTANT_Float: // fall through
421 case JVM_CONSTANT_Integer: // fall through
422 case JVM_CONSTANT_Utf8: // fall through
423
424 // This was an indirect CP entry, but it has been changed into
425 // Symbol*s so this entry can be directly appended.
426 case JVM_CONSTANT_String: // fall through
427 {
428 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p);
429
430 if (scratch_i != *merge_cp_length_p) {
431 // The new entry in *merge_cp_p is at a different index than
432 // the new entry in scratch_cp so we need to map the index values.
433 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
434 }
435 (*merge_cp_length_p)++;
436 } break;
437
438 // this is an indirect CP entry so it needs special handling
439 case JVM_CONSTANT_NameAndType:
440 {
441 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i);
442 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p,
443 merge_cp_length_p);
444
445 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i);
446 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i,
447 merge_cp_p, merge_cp_length_p);
448
449 // If the referenced entries already exist in *merge_cp_p, then
450 // both new_name_ref_i and new_signature_ref_i will both be 0.
451 // In that case, all we are appending is the current entry.
452 if (new_name_ref_i != name_ref_i) {
453 log_trace(redefine, class, constantpool)
454 ("NameAndType entry@%d name_ref_index change: %d to %d",
455 *merge_cp_length_p, name_ref_i, new_name_ref_i);
456 }
457 if (new_signature_ref_i != signature_ref_i) {
458 log_trace(redefine, class, constantpool)
459 ("NameAndType entry@%d signature_ref_index change: %d to %d",
460 *merge_cp_length_p, signature_ref_i, new_signature_ref_i);
461 }
462
463 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p,
464 new_name_ref_i, new_signature_ref_i);
465 if (scratch_i != *merge_cp_length_p) {
466 // The new entry in *merge_cp_p is at a different index than
467 // the new entry in scratch_cp so we need to map the index values.
468 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
469 }
470 (*merge_cp_length_p)++;
471 } break;
472
473 // this is a double-indirect CP entry so it needs special handling
474 case JVM_CONSTANT_Fieldref: // fall through
475 case JVM_CONSTANT_InterfaceMethodref: // fall through
476 case JVM_CONSTANT_Methodref:
477 {
478 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i);
479 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i,
480 merge_cp_p, merge_cp_length_p);
481
482 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i);
483 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i,
484 merge_cp_p, merge_cp_length_p);
485
486 const char *entry_name = nullptr;
487 switch (scratch_cp->tag_at(scratch_i).value()) {
488 case JVM_CONSTANT_Fieldref:
489 entry_name = "Fieldref";
490 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i,
491 new_name_and_type_ref_i);
492 break;
493 case JVM_CONSTANT_InterfaceMethodref:
494 entry_name = "IFMethodref";
495 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p,
496 new_klass_ref_i, new_name_and_type_ref_i);
497 break;
498 case JVM_CONSTANT_Methodref:
499 entry_name = "Methodref";
500 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i,
501 new_name_and_type_ref_i);
502 break;
503 default:
504 guarantee(false, "bad switch");
505 break;
506 }
507
508 if (klass_ref_i != new_klass_ref_i) {
509 log_trace(redefine, class, constantpool)
510 ("%s entry@%d class_index changed: %d to %d", entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i);
511 }
512 if (name_and_type_ref_i != new_name_and_type_ref_i) {
513 log_trace(redefine, class, constantpool)
514 ("%s entry@%d name_and_type_index changed: %d to %d",
515 entry_name, *merge_cp_length_p, name_and_type_ref_i, new_name_and_type_ref_i);
516 }
517
518 if (scratch_i != *merge_cp_length_p) {
519 // The new entry in *merge_cp_p is at a different index than
520 // the new entry in scratch_cp so we need to map the index values.
521 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
522 }
523 (*merge_cp_length_p)++;
524 } break;
525
526 // this is an indirect CP entry so it needs special handling
527 case JVM_CONSTANT_MethodType:
528 {
529 int ref_i = scratch_cp->method_type_index_at(scratch_i);
530 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
531 merge_cp_length_p);
532 if (new_ref_i != ref_i) {
533 log_trace(redefine, class, constantpool)
534 ("MethodType entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i);
535 }
536 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i);
537 if (scratch_i != *merge_cp_length_p) {
538 // The new entry in *merge_cp_p is at a different index than
539 // the new entry in scratch_cp so we need to map the index values.
540 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
541 }
542 (*merge_cp_length_p)++;
543 } break;
544
545 // this is an indirect CP entry so it needs special handling
546 case JVM_CONSTANT_MethodHandle:
547 {
548 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i);
549 int ref_i = scratch_cp->method_handle_index_at(scratch_i);
550 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
551 merge_cp_length_p);
552 if (new_ref_i != ref_i) {
553 log_trace(redefine, class, constantpool)
554 ("MethodHandle entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i);
555 }
556 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i);
557 if (scratch_i != *merge_cp_length_p) {
558 // The new entry in *merge_cp_p is at a different index than
559 // the new entry in scratch_cp so we need to map the index values.
560 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
561 }
562 (*merge_cp_length_p)++;
563 } break;
564
565 // this is an indirect CP entry so it needs special handling
566 case JVM_CONSTANT_Dynamic: // fall through
567 case JVM_CONSTANT_InvokeDynamic:
568 {
569 // Index of the bootstrap specifier in the operands array
570 int old_bs_i = scratch_cp->bootstrap_methods_attribute_index(scratch_i);
571 int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p,
572 merge_cp_length_p);
573 // The bootstrap method NameAndType_info index
574 int old_ref_i = scratch_cp->bootstrap_name_and_type_ref_index_at(scratch_i);
575 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
576 merge_cp_length_p);
577 if (new_bs_i != old_bs_i) {
578 log_trace(redefine, class, constantpool)
579 ("Dynamic entry@%d bootstrap_method_attr_index change: %d to %d",
580 *merge_cp_length_p, old_bs_i, new_bs_i);
581 }
582 if (new_ref_i != old_ref_i) {
583 log_trace(redefine, class, constantpool)
584 ("Dynamic entry@%d name_and_type_index change: %d to %d", *merge_cp_length_p, old_ref_i, new_ref_i);
585 }
586
587 if (scratch_cp->tag_at(scratch_i).is_dynamic_constant())
588 (*merge_cp_p)->dynamic_constant_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
589 else
590 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
591 if (scratch_i != *merge_cp_length_p) {
592 // The new entry in *merge_cp_p is at a different index than
593 // the new entry in scratch_cp so we need to map the index values.
594 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
595 }
596 (*merge_cp_length_p)++;
597 } break;
598
599 // At this stage, Class or UnresolvedClass could be in scratch_cp, but not
600 // ClassIndex
601 case JVM_CONSTANT_ClassIndex: // fall through
602
603 // Invalid is used as the tag for the second constant pool entry
604 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
605 // not be seen by itself.
606 case JVM_CONSTANT_Invalid: // fall through
607
608 // At this stage, String could be here, but not StringIndex
609 case JVM_CONSTANT_StringIndex: // fall through
610
611 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be here
612 case JVM_CONSTANT_UnresolvedClassInError: // fall through
613
614 default:
615 {
616 // leave a breadcrumb
617 jbyte bad_value = scratch_cp->tag_at(scratch_i).value();
618 ShouldNotReachHere();
619 } break;
620 } // end switch tag value
621 } // end append_entry()
622
623
624 int VM_RedefineClasses::find_or_append_indirect_entry(const constantPoolHandle& scratch_cp,
625 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) {
626
627 int new_ref_i = ref_i;
628 bool match = (ref_i < *merge_cp_length_p) &&
629 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i);
630
631 if (!match) {
632 // forward reference in *merge_cp_p or not a direct match
633 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p);
634 if (found_i != 0) {
635 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree");
636 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry.
637 new_ref_i = found_i;
638 map_index(scratch_cp, ref_i, found_i);
639 } else {
640 // no match found so we have to append this entry to *merge_cp_p
641 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p);
642 // The above call to append_entry() can only append one entry
643 // so the post call query of *merge_cp_length_p is only for
644 // the sake of consistency.
645 new_ref_i = *merge_cp_length_p - 1;
646 }
647 }
648
649 return new_ref_i;
650 } // end find_or_append_indirect_entry()
651
652
653 // Append a bootstrap specifier into the merge_cp operands that is semantically equal
654 // to the scratch_cp operands bootstrap specifier passed by the old_bs_i index.
655 // Recursively append new merge_cp entries referenced by the new bootstrap specifier.
656 void VM_RedefineClasses::append_operand(const constantPoolHandle& scratch_cp, int old_bs_i,
657 constantPoolHandle *merge_cp_p, int *merge_cp_length_p) {
658
659 int old_ref_i = scratch_cp->operand_bootstrap_method_ref_index_at(old_bs_i);
660 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
661 merge_cp_length_p);
662 if (new_ref_i != old_ref_i) {
663 log_trace(redefine, class, constantpool)
664 ("operands entry@%d bootstrap method ref_index change: %d to %d", _operands_cur_length, old_ref_i, new_ref_i);
665 }
666
667 Array<u2>* merge_ops = (*merge_cp_p)->operands();
668 int new_bs_i = _operands_cur_length;
669 // We have _operands_cur_length == 0 when the merge_cp operands is empty yet.
670 // However, the operand_offset_at(0) was set in the extend_operands() call.
671 int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0)
672 : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1);
673 int argc = scratch_cp->operand_argument_count_at(old_bs_i);
674
675 ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base);
676 merge_ops->at_put(new_base++, new_ref_i);
677 merge_ops->at_put(new_base++, argc);
678
679 for (int i = 0; i < argc; i++) {
680 int old_arg_ref_i = scratch_cp->operand_argument_index_at(old_bs_i, i);
681 int new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p,
682 merge_cp_length_p);
683 merge_ops->at_put(new_base++, new_arg_ref_i);
684 if (new_arg_ref_i != old_arg_ref_i) {
685 log_trace(redefine, class, constantpool)
686 ("operands entry@%d bootstrap method argument ref_index change: %d to %d",
687 _operands_cur_length, old_arg_ref_i, new_arg_ref_i);
688 }
689 }
690 if (old_bs_i != _operands_cur_length) {
691 // The bootstrap specifier in *merge_cp_p is at a different index than
692 // that in scratch_cp so we need to map the index values.
693 map_operand_index(old_bs_i, new_bs_i);
694 }
695 _operands_cur_length++;
696 } // end append_operand()
697
698
699 int VM_RedefineClasses::find_or_append_operand(const constantPoolHandle& scratch_cp,
700 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) {
701
702 int new_bs_i = old_bs_i; // bootstrap specifier index
703 bool match = (old_bs_i < _operands_cur_length) &&
704 scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i);
705
706 if (!match) {
707 // forward reference in *merge_cp_p or not a direct match
708 int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p,
709 _operands_cur_length);
710 if (found_i != -1) {
711 guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree");
712 // found a matching operand somewhere else in *merge_cp_p so just need a mapping
713 new_bs_i = found_i;
714 map_operand_index(old_bs_i, found_i);
715 } else {
716 // no match found so we have to append this bootstrap specifier to *merge_cp_p
717 append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p);
718 new_bs_i = _operands_cur_length - 1;
719 }
720 }
721 return new_bs_i;
722 } // end find_or_append_operand()
723
724
725 void VM_RedefineClasses::finalize_operands_merge(const constantPoolHandle& merge_cp, TRAPS) {
726 if (merge_cp->operands() == nullptr) {
727 return;
728 }
729 // Shrink the merge_cp operands
730 merge_cp->shrink_operands(_operands_cur_length, CHECK);
731
732 if (log_is_enabled(Trace, redefine, class, constantpool)) {
733 // don't want to loop unless we are tracing
734 int count = 0;
735 for (int i = 1; i < _operands_index_map_p->length(); i++) {
736 int value = _operands_index_map_p->at(i);
737 if (value != -1) {
738 log_trace(redefine, class, constantpool)("operands_index_map[%d]: old=%d new=%d", count, i, value);
739 count++;
740 }
741 }
742 }
743 // Clean-up
744 _operands_index_map_p = nullptr;
745 _operands_cur_length = 0;
746 _operands_index_map_count = 0;
747 } // end finalize_operands_merge()
748
749 // Symbol* comparator for qsort
750 // The caller must have an active ResourceMark.
751 static int symcmp(const void* a, const void* b) {
752 char* astr = (*(Symbol**)a)->as_C_string();
753 char* bstr = (*(Symbol**)b)->as_C_string();
754 return strcmp(astr, bstr);
755 }
756
757 // The caller must have an active ResourceMark.
758 static jvmtiError check_attribute_arrays(const char* attr_name,
759 InstanceKlass* the_class, InstanceKlass* scratch_class,
760 Array<u2>* the_array, Array<u2>* scr_array) {
761 bool the_array_exists = the_array != Universe::the_empty_short_array();
762 bool scr_array_exists = scr_array != Universe::the_empty_short_array();
763
764 int array_len = the_array->length();
765 if (the_array_exists && scr_array_exists) {
766 if (array_len != scr_array->length()) {
767 log_trace(redefine, class)
768 ("redefined class %s attribute change error: %s len=%d changed to len=%d",
769 the_class->external_name(), attr_name, array_len, scr_array->length());
770 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
771 }
772
773 // The order of entries in the attribute array is not specified so we
774 // have to explicitly check for the same contents. We do this by copying
775 // the referenced symbols into their own arrays, sorting them and then
776 // comparing each element pair.
777
778 Symbol** the_syms = NEW_RESOURCE_ARRAY_RETURN_NULL(Symbol*, array_len);
779 Symbol** scr_syms = NEW_RESOURCE_ARRAY_RETURN_NULL(Symbol*, array_len);
780
781 if (the_syms == nullptr || scr_syms == nullptr) {
782 return JVMTI_ERROR_OUT_OF_MEMORY;
783 }
784
785 for (int i = 0; i < array_len; i++) {
786 int the_cp_index = the_array->at(i);
787 int scr_cp_index = scr_array->at(i);
788 the_syms[i] = the_class->constants()->klass_name_at(the_cp_index);
789 scr_syms[i] = scratch_class->constants()->klass_name_at(scr_cp_index);
790 }
791
792 qsort(the_syms, array_len, sizeof(Symbol*), symcmp);
793 qsort(scr_syms, array_len, sizeof(Symbol*), symcmp);
794
795 for (int i = 0; i < array_len; i++) {
796 if (the_syms[i] != scr_syms[i]) {
797 log_info(redefine, class)
798 ("redefined class %s attribute change error: %s[%d]: %s changed to %s",
799 the_class->external_name(), attr_name, i,
800 the_syms[i]->as_C_string(), scr_syms[i]->as_C_string());
801 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
802 }
803 }
804 } else if (the_array_exists ^ scr_array_exists) {
805 const char* action_str = (the_array_exists) ? "removed" : "added";
806 log_info(redefine, class)
807 ("redefined class %s attribute change error: %s attribute %s",
808 the_class->external_name(), attr_name, action_str);
809 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
810 }
811 return JVMTI_ERROR_NONE;
812 }
813
814 static jvmtiError check_nest_attributes(InstanceKlass* the_class,
815 InstanceKlass* scratch_class) {
816 // Check whether the class NestHost attribute has been changed.
817 Thread* thread = Thread::current();
818 ResourceMark rm(thread);
819 u2 the_nest_host_idx = the_class->nest_host_index();
820 u2 scr_nest_host_idx = scratch_class->nest_host_index();
821
822 if (the_nest_host_idx != 0 && scr_nest_host_idx != 0) {
823 Symbol* the_sym = the_class->constants()->klass_name_at(the_nest_host_idx);
824 Symbol* scr_sym = scratch_class->constants()->klass_name_at(scr_nest_host_idx);
825 if (the_sym != scr_sym) {
826 log_info(redefine, class, nestmates)
827 ("redefined class %s attribute change error: NestHost class: %s replaced with: %s",
828 the_class->external_name(), the_sym->as_C_string(), scr_sym->as_C_string());
829 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
830 }
831 } else if ((the_nest_host_idx == 0) ^ (scr_nest_host_idx == 0)) {
832 const char* action_str = (the_nest_host_idx != 0) ? "removed" : "added";
833 log_info(redefine, class, nestmates)
834 ("redefined class %s attribute change error: NestHost attribute %s",
835 the_class->external_name(), action_str);
836 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
837 }
838
839 // Check whether the class NestMembers attribute has been changed.
840 return check_attribute_arrays("NestMembers",
841 the_class, scratch_class,
842 the_class->nest_members(),
843 scratch_class->nest_members());
844 }
845
846 // Return an error status if the class Record attribute was changed.
847 static jvmtiError check_record_attribute(InstanceKlass* the_class, InstanceKlass* scratch_class) {
848 // Get lists of record components.
849 Array<RecordComponent*>* the_record = the_class->record_components();
850 Array<RecordComponent*>* scr_record = scratch_class->record_components();
851 bool the_record_exists = the_record != nullptr;
852 bool scr_record_exists = scr_record != nullptr;
853
854 if (the_record_exists && scr_record_exists) {
855 int the_num_components = the_record->length();
856 int scr_num_components = scr_record->length();
857 if (the_num_components != scr_num_components) {
858 log_info(redefine, class, record)
859 ("redefined class %s attribute change error: Record num_components=%d changed to num_components=%d",
860 the_class->external_name(), the_num_components, scr_num_components);
861 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
862 }
863
864 // Compare each field in each record component.
865 ConstantPool* the_cp = the_class->constants();
866 ConstantPool* scr_cp = scratch_class->constants();
867 for (int x = 0; x < the_num_components; x++) {
868 RecordComponent* the_component = the_record->at(x);
869 RecordComponent* scr_component = scr_record->at(x);
870 const Symbol* const the_name = the_cp->symbol_at(the_component->name_index());
871 const Symbol* const scr_name = scr_cp->symbol_at(scr_component->name_index());
872 const Symbol* const the_descr = the_cp->symbol_at(the_component->descriptor_index());
873 const Symbol* const scr_descr = scr_cp->symbol_at(scr_component->descriptor_index());
874 if (the_name != scr_name || the_descr != scr_descr) {
875 log_info(redefine, class, record)
876 ("redefined class %s attribute change error: Record name_index, descriptor_index, and/or attributes_count changed",
877 the_class->external_name());
878 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
879 }
880
881 int the_gen_sig = the_component->generic_signature_index();
882 int scr_gen_sig = scr_component->generic_signature_index();
883 const Symbol* const the_gen_sig_sym = (the_gen_sig == 0 ? nullptr :
884 the_cp->symbol_at(the_component->generic_signature_index()));
885 const Symbol* const scr_gen_sig_sym = (scr_gen_sig == 0 ? nullptr :
886 scr_cp->symbol_at(scr_component->generic_signature_index()));
887 if (the_gen_sig_sym != scr_gen_sig_sym) {
888 log_info(redefine, class, record)
889 ("redefined class %s attribute change error: Record generic_signature attribute changed",
890 the_class->external_name());
891 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
892 }
893
894 // It's okay if a record component's annotations were changed.
895 }
896
897 } else if (the_record_exists ^ scr_record_exists) {
898 const char* action_str = (the_record_exists) ? "removed" : "added";
899 log_info(redefine, class, record)
900 ("redefined class %s attribute change error: Record attribute %s",
901 the_class->external_name(), action_str);
902 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
903 }
904
905 return JVMTI_ERROR_NONE;
906 }
907
908
909 static jvmtiError check_permitted_subclasses_attribute(InstanceKlass* the_class,
910 InstanceKlass* scratch_class) {
911 Thread* thread = Thread::current();
912 ResourceMark rm(thread);
913
914 // Check whether the class PermittedSubclasses attribute has been changed.
915 return check_attribute_arrays("PermittedSubclasses",
916 the_class, scratch_class,
917 the_class->permitted_subclasses(),
918 scratch_class->permitted_subclasses());
919 }
920
921 static jvmtiError check_preload_attribute(InstanceKlass* the_class,
922 InstanceKlass* scratch_class) {
923 Thread* thread = Thread::current();
924 ResourceMark rm(thread);
925
926 // Check whether the class Preload attribute has been changed.
927 return check_attribute_arrays("Preload",
928 the_class, scratch_class,
929 the_class->preload_classes(),
930 scratch_class->preload_classes());
931 }
932
933 static bool can_add_or_delete(Method* m) {
934 // Compatibility mode
935 return (AllowRedefinitionToAddDeleteMethods &&
936 (m->is_private() && (m->is_static() || m->is_final())));
937 }
938
939 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions(
940 InstanceKlass* the_class,
941 InstanceKlass* scratch_class) {
942 int i;
943
944 // Check superclasses, or rather their names, since superclasses themselves can be
945 // requested to replace.
946 // Check for null superclass first since this might be java.lang.Object
947 if (the_class->super() != scratch_class->super() &&
948 (the_class->super() == nullptr || scratch_class->super() == nullptr ||
949 the_class->super()->name() !=
950 scratch_class->super()->name())) {
951 log_info(redefine, class, normalize)
952 ("redefined class %s superclass change error: superclass changed from %s to %s.",
953 the_class->external_name(),
954 the_class->super() == nullptr ? "null" : the_class->super()->external_name(),
955 scratch_class->super() == nullptr ? "null" : scratch_class->super()->external_name());
956 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
957 }
958
959 // Check if the number, names and order of directly implemented interfaces are the same.
960 // I think in principle we should just check if the sets of names of directly implemented
961 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the
962 // .java file, also changes in .class file) should not matter. However, comparing sets is
963 // technically a bit more difficult, and, more importantly, I am not sure at present that the
964 // order of interfaces does not matter on the implementation level, i.e. that the VM does not
965 // rely on it somewhere.
966 Array<InstanceKlass*>* k_interfaces = the_class->local_interfaces();
967 Array<InstanceKlass*>* k_new_interfaces = scratch_class->local_interfaces();
968 int n_intfs = k_interfaces->length();
969 if (n_intfs != k_new_interfaces->length()) {
970 log_info(redefine, class, normalize)
971 ("redefined class %s interfaces change error: number of implemented interfaces changed from %d to %d.",
972 the_class->external_name(), n_intfs, k_new_interfaces->length());
973 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
974 }
975 for (i = 0; i < n_intfs; i++) {
976 if (k_interfaces->at(i)->name() !=
977 k_new_interfaces->at(i)->name()) {
978 log_info(redefine, class, normalize)
979 ("redefined class %s interfaces change error: interface changed from %s to %s.",
980 the_class->external_name(),
981 k_interfaces->at(i)->external_name(), k_new_interfaces->at(i)->external_name());
982 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
983 }
984 }
985
986 // Check whether class is in the error init state.
987 if (the_class->is_in_error_state()) {
988 log_info(redefine, class, normalize)
989 ("redefined class %s is in error init state.", the_class->external_name());
990 // TBD #5057930: special error code is needed in 1.6
991 return JVMTI_ERROR_INVALID_CLASS;
992 }
993
994 // Check whether the nest-related attributes have been changed.
995 jvmtiError err = check_nest_attributes(the_class, scratch_class);
996 if (err != JVMTI_ERROR_NONE) {
997 return err;
998 }
999
1000 // Check whether the Record attribute has been changed.
1001 err = check_record_attribute(the_class, scratch_class);
1002 if (err != JVMTI_ERROR_NONE) {
1003 return err;
1004 }
1005
1006 // Check whether the PermittedSubclasses attribute has been changed.
1007 err = check_permitted_subclasses_attribute(the_class, scratch_class);
1008 if (err != JVMTI_ERROR_NONE) {
1009 return err;
1010 }
1011
1012 // Check whether the Preload attribute has been changed.
1013 err = check_preload_attribute(the_class, scratch_class);
1014 if (err != JVMTI_ERROR_NONE) {
1015 return err;
1016 }
1017
1018 // Check whether class modifiers are the same.
1019 jushort old_flags = (jushort) the_class->access_flags().get_flags();
1020 jushort new_flags = (jushort) scratch_class->access_flags().get_flags();
1021 if (old_flags != new_flags) {
1022 log_info(redefine, class, normalize)
1023 ("redefined class %s modifiers change error: modifiers changed from %d to %d.",
1024 the_class->external_name(), old_flags, new_flags);
1025 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED;
1026 }
1027
1028 // Check if the number, names, types and order of fields declared in these classes
1029 // are the same.
1030 JavaFieldStream old_fs(the_class);
1031 JavaFieldStream new_fs(scratch_class);
1032 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) {
1033 // name and signature
1034 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index());
1035 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index());
1036 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index());
1037 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index());
1038 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) {
1039 log_info(redefine, class, normalize)
1040 ("redefined class %s fields change error: field %s %s changed to %s %s.",
1041 the_class->external_name(),
1042 sig_sym1->as_C_string(), name_sym1->as_C_string(),
1043 sig_sym2->as_C_string(), name_sym2->as_C_string());
1044 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
1045 }
1046 // offset
1047 if (old_fs.offset() != new_fs.offset()) {
1048 log_info(redefine, class, normalize)
1049 ("redefined class %s field %s change error: offset changed from %d to %d.",
1050 the_class->external_name(), name_sym2->as_C_string(), old_fs.offset(), new_fs.offset());
1051 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
1052 }
1053 // access
1054 old_flags = old_fs.access_flags().as_short();
1055 new_flags = new_fs.access_flags().as_short();
1056 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) {
1057 log_info(redefine, class, normalize)
1058 ("redefined class %s field %s change error: modifiers changed from %d to %d.",
1059 the_class->external_name(), name_sym2->as_C_string(), old_flags, new_flags);
1060 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
1061 }
1062 }
1063
1064 // If both streams aren't done then we have a differing number of
1065 // fields.
1066 if (!old_fs.done() || !new_fs.done()) {
1067 const char* action = old_fs.done() ? "added" : "deleted";
1068 log_info(redefine, class, normalize)
1069 ("redefined class %s fields change error: some fields were %s.",
1070 the_class->external_name(), action);
1071 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
1072 }
1073
1074 // Do a parallel walk through the old and new methods. Detect
1075 // cases where they match (exist in both), have been added in
1076 // the new methods, or have been deleted (exist only in the
1077 // old methods). The class file parser places methods in order
1078 // by method name, but does not order overloaded methods by
1079 // signature. In order to determine what fate befell the methods,
1080 // this code places the overloaded new methods that have matching
1081 // old methods in the same order as the old methods and places
1082 // new overloaded methods at the end of overloaded methods of
1083 // that name. The code for this order normalization is adapted
1084 // from the algorithm used in InstanceKlass::find_method().
1085 // Since we are swapping out of order entries as we find them,
1086 // we only have to search forward through the overloaded methods.
1087 // Methods which are added and have the same name as an existing
1088 // method (but different signature) will be put at the end of
1089 // the methods with that name, and the name mismatch code will
1090 // handle them.
1091 Array<Method*>* k_old_methods(the_class->methods());
1092 Array<Method*>* k_new_methods(scratch_class->methods());
1093 int n_old_methods = k_old_methods->length();
1094 int n_new_methods = k_new_methods->length();
1095 Thread* thread = Thread::current();
1096
1097 int ni = 0;
1098 int oi = 0;
1099 while (true) {
1100 Method* k_old_method;
1101 Method* k_new_method;
1102 enum { matched, added, deleted, undetermined } method_was = undetermined;
1103
1104 if (oi >= n_old_methods) {
1105 if (ni >= n_new_methods) {
1106 break; // we've looked at everything, done
1107 }
1108 // New method at the end
1109 k_new_method = k_new_methods->at(ni);
1110 method_was = added;
1111 } else if (ni >= n_new_methods) {
1112 // Old method, at the end, is deleted
1113 k_old_method = k_old_methods->at(oi);
1114 method_was = deleted;
1115 } else {
1116 // There are more methods in both the old and new lists
1117 k_old_method = k_old_methods->at(oi);
1118 k_new_method = k_new_methods->at(ni);
1119 if (k_old_method->name() != k_new_method->name()) {
1120 // Methods are sorted by method name, so a mismatch means added
1121 // or deleted
1122 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) {
1123 method_was = added;
1124 } else {
1125 method_was = deleted;
1126 }
1127 } else if (k_old_method->signature() == k_new_method->signature()) {
1128 // Both the name and signature match
1129 method_was = matched;
1130 } else {
1131 // The name matches, but the signature doesn't, which means we have to
1132 // search forward through the new overloaded methods.
1133 int nj; // outside the loop for post-loop check
1134 for (nj = ni + 1; nj < n_new_methods; nj++) {
1135 Method* m = k_new_methods->at(nj);
1136 if (k_old_method->name() != m->name()) {
1137 // reached another method name so no more overloaded methods
1138 method_was = deleted;
1139 break;
1140 }
1141 if (k_old_method->signature() == m->signature()) {
1142 // found a match so swap the methods
1143 k_new_methods->at_put(ni, m);
1144 k_new_methods->at_put(nj, k_new_method);
1145 k_new_method = m;
1146 method_was = matched;
1147 break;
1148 }
1149 }
1150
1151 if (nj >= n_new_methods) {
1152 // reached the end without a match; so method was deleted
1153 method_was = deleted;
1154 }
1155 }
1156 }
1157
1158 switch (method_was) {
1159 case matched:
1160 // methods match, be sure modifiers do too
1161 old_flags = (jushort) k_old_method->access_flags().get_flags();
1162 new_flags = (jushort) k_new_method->access_flags().get_flags();
1163 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) {
1164 log_info(redefine, class, normalize)
1165 ("redefined class %s method %s modifiers error: modifiers changed from %d to %d",
1166 the_class->external_name(), k_old_method->name_and_sig_as_C_string(), old_flags, new_flags);
1167 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED;
1168 }
1169 {
1170 u2 new_num = k_new_method->method_idnum();
1171 u2 old_num = k_old_method->method_idnum();
1172 if (new_num != old_num) {
1173 Method* idnum_owner = scratch_class->method_with_idnum(old_num);
1174 if (idnum_owner != nullptr) {
1175 // There is already a method assigned this idnum -- switch them
1176 // Take current and original idnum from the new_method
1177 idnum_owner->set_method_idnum(new_num);
1178 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum());
1179 }
1180 // Take current and original idnum from the old_method
1181 k_new_method->set_method_idnum(old_num);
1182 k_new_method->set_orig_method_idnum(k_old_method->orig_method_idnum());
1183 if (thread->has_pending_exception()) {
1184 return JVMTI_ERROR_OUT_OF_MEMORY;
1185 }
1186 }
1187 }
1188 log_trace(redefine, class, normalize)
1189 ("Method matched: new: %s [%d] == old: %s [%d]",
1190 k_new_method->name_and_sig_as_C_string(), ni, k_old_method->name_and_sig_as_C_string(), oi);
1191 // advance to next pair of methods
1192 ++oi;
1193 ++ni;
1194 break;
1195 case added:
1196 // method added, see if it is OK
1197 if (!can_add_or_delete(k_new_method)) {
1198 log_info(redefine, class, normalize)
1199 ("redefined class %s methods error: added method: %s [%d]",
1200 the_class->external_name(), k_new_method->name_and_sig_as_C_string(), ni);
1201 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
1202 }
1203 {
1204 u2 num = the_class->next_method_idnum();
1205 if (num == ConstMethod::UNSET_IDNUM) {
1206 // cannot add any more methods
1207 log_info(redefine, class, normalize)
1208 ("redefined class %s methods error: can't create ID for new method %s [%d]",
1209 the_class->external_name(), k_new_method->name_and_sig_as_C_string(), ni);
1210 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
1211 }
1212 u2 new_num = k_new_method->method_idnum();
1213 Method* idnum_owner = scratch_class->method_with_idnum(num);
1214 if (idnum_owner != nullptr) {
1215 // There is already a method assigned this idnum -- switch them
1216 // Take current and original idnum from the new_method
1217 idnum_owner->set_method_idnum(new_num);
1218 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum());
1219 }
1220 k_new_method->set_method_idnum(num);
1221 k_new_method->set_orig_method_idnum(num);
1222 if (thread->has_pending_exception()) {
1223 return JVMTI_ERROR_OUT_OF_MEMORY;
1224 }
1225 }
1226 log_trace(redefine, class, normalize)
1227 ("Method added: new: %s [%d]", k_new_method->name_and_sig_as_C_string(), ni);
1228 ++ni; // advance to next new method
1229 break;
1230 case deleted:
1231 // method deleted, see if it is OK
1232 if (!can_add_or_delete(k_old_method)) {
1233 log_info(redefine, class, normalize)
1234 ("redefined class %s methods error: deleted method %s [%d]",
1235 the_class->external_name(), k_old_method->name_and_sig_as_C_string(), oi);
1236 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED;
1237 }
1238 log_trace(redefine, class, normalize)
1239 ("Method deleted: old: %s [%d]", k_old_method->name_and_sig_as_C_string(), oi);
1240 ++oi; // advance to next old method
1241 break;
1242 default:
1243 ShouldNotReachHere();
1244 }
1245 }
1246
1247 return JVMTI_ERROR_NONE;
1248 }
1249
1250
1251 // Find new constant pool index value for old constant pool index value
1252 // by searching the index map. Returns zero (0) if there is no mapped
1253 // value for the old constant pool index.
1254 int VM_RedefineClasses::find_new_index(int old_index) {
1255 if (_index_map_count == 0) {
1256 // map is empty so nothing can be found
1257 return 0;
1258 }
1259
1260 if (old_index < 1 || old_index >= _index_map_p->length()) {
1261 // The old_index is out of range so it is not mapped. This should
1262 // not happen in regular constant pool merging use, but it can
1263 // happen if a corrupt annotation is processed.
1264 return 0;
1265 }
1266
1267 int value = _index_map_p->at(old_index);
1268 if (value == -1) {
1269 // the old_index is not mapped
1270 return 0;
1271 }
1272
1273 return value;
1274 } // end find_new_index()
1275
1276
1277 // Find new bootstrap specifier index value for old bootstrap specifier index
1278 // value by searching the index map. Returns unused index (-1) if there is
1279 // no mapped value for the old bootstrap specifier index.
1280 int VM_RedefineClasses::find_new_operand_index(int old_index) {
1281 if (_operands_index_map_count == 0) {
1282 // map is empty so nothing can be found
1283 return -1;
1284 }
1285
1286 if (old_index == -1 || old_index >= _operands_index_map_p->length()) {
1287 // The old_index is out of range so it is not mapped.
1288 // This should not happen in regular constant pool merging use.
1289 return -1;
1290 }
1291
1292 int value = _operands_index_map_p->at(old_index);
1293 if (value == -1) {
1294 // the old_index is not mapped
1295 return -1;
1296 }
1297
1298 return value;
1299 } // end find_new_operand_index()
1300
1301
1302 // Returns true if the current mismatch is due to a resolved/unresolved
1303 // class pair. Otherwise, returns false.
1304 bool VM_RedefineClasses::is_unresolved_class_mismatch(const constantPoolHandle& cp1,
1305 int index1, const constantPoolHandle& cp2, int index2) {
1306
1307 jbyte t1 = cp1->tag_at(index1).value();
1308 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) {
1309 return false; // wrong entry type; not our special case
1310 }
1311
1312 jbyte t2 = cp2->tag_at(index2).value();
1313 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) {
1314 return false; // wrong entry type; not our special case
1315 }
1316
1317 if (t1 == t2) {
1318 return false; // not a mismatch; not our special case
1319 }
1320
1321 char *s1 = cp1->klass_name_at(index1)->as_C_string();
1322 char *s2 = cp2->klass_name_at(index2)->as_C_string();
1323 if (strcmp(s1, s2) != 0) {
1324 return false; // strings don't match; not our special case
1325 }
1326
1327 return true; // made it through the gauntlet; this is our special case
1328 } // end is_unresolved_class_mismatch()
1329
1330
1331 // The bug 6214132 caused the verification to fail.
1332 // 1. What's done in RedefineClasses() before verification:
1333 // a) A reference to the class being redefined (_the_class) and a
1334 // reference to new version of the class (_scratch_class) are
1335 // saved here for use during the bytecode verification phase of
1336 // RedefineClasses.
1337 // b) The _java_mirror field from _the_class is copied to the
1338 // _java_mirror field in _scratch_class. This means that a jclass
1339 // returned for _the_class or _scratch_class will refer to the
1340 // same Java mirror. The verifier will see the "one true mirror"
1341 // for the class being verified.
1342 // 2. See comments in JvmtiThreadState for what is done during verification.
1343
1344 class RedefineVerifyMark : public StackObj {
1345 private:
1346 JvmtiThreadState* _state;
1347 Klass* _scratch_class;
1348 OopHandle _scratch_mirror;
1349
1350 public:
1351
1352 RedefineVerifyMark(Klass* the_class, Klass* scratch_class,
1353 JvmtiThreadState* state) : _state(state), _scratch_class(scratch_class)
1354 {
1355 _state->set_class_versions_map(the_class, scratch_class);
1356 _scratch_mirror = the_class->java_mirror_handle(); // this is a copy that is swapped
1357 _scratch_class->swap_java_mirror_handle(_scratch_mirror);
1358 }
1359
1360 ~RedefineVerifyMark() {
1361 // Restore the scratch class's mirror, so when scratch_class is removed
1362 // the correct mirror pointing to it can be cleared.
1363 _scratch_class->swap_java_mirror_handle(_scratch_mirror);
1364 _state->clear_class_versions_map();
1365 }
1366 };
1367
1368
1369 jvmtiError VM_RedefineClasses::load_new_class_versions() {
1370
1371 // For consistency allocate memory using os::malloc wrapper.
1372 _scratch_classes = (InstanceKlass**)
1373 os::malloc(sizeof(InstanceKlass*) * _class_count, mtClass);
1374 if (_scratch_classes == nullptr) {
1375 return JVMTI_ERROR_OUT_OF_MEMORY;
1376 }
1377 // Zero initialize the _scratch_classes array.
1378 for (int i = 0; i < _class_count; i++) {
1379 _scratch_classes[i] = nullptr;
1380 }
1381
1382 JavaThread* current = JavaThread::current();
1383 ResourceMark rm(current);
1384
1385 JvmtiThreadState *state = JvmtiThreadState::state_for(current);
1386 // state can only be null if the current thread is exiting which
1387 // should not happen since we're trying to do a RedefineClasses
1388 guarantee(state != nullptr, "exiting thread calling load_new_class_versions");
1389 for (int i = 0; i < _class_count; i++) {
1390 // Create HandleMark so that any handles created while loading new class
1391 // versions are deleted. Constant pools are deallocated while merging
1392 // constant pools
1393 HandleMark hm(current);
1394 InstanceKlass* the_class = get_ik(_class_defs[i].klass);
1395
1396 log_debug(redefine, class, load)
1397 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)",
1398 the_class->external_name(), _class_load_kind, os::available_memory() >> 10);
1399
1400 ClassFileStream st((u1*)_class_defs[i].class_bytes,
1401 _class_defs[i].class_byte_count,
1402 "__VM_RedefineClasses__",
1403 ClassFileStream::verify);
1404
1405 // Set redefined class handle in JvmtiThreadState class.
1406 // This redefined class is sent to agent event handler for class file
1407 // load hook event.
1408 state->set_class_being_redefined(the_class, _class_load_kind);
1409
1410 JavaThread* THREAD = current; // For exception macros.
1411 ExceptionMark em(THREAD);
1412 Handle protection_domain(THREAD, the_class->protection_domain());
1413 ClassLoadInfo cl_info(protection_domain);
1414 // Parse and create a class from the bytes, but this class isn't added
1415 // to the dictionary, so do not call resolve_from_stream.
1416 InstanceKlass* scratch_class = KlassFactory::create_from_stream(&st,
1417 the_class->name(),
1418 the_class->class_loader_data(),
1419 cl_info,
1420 THREAD);
1421
1422 // Clear class_being_redefined just to be sure.
1423 state->clear_class_being_redefined();
1424
1425 // TODO: if this is retransform, and nothing changed we can skip it
1426
1427 // Need to clean up allocated InstanceKlass if there's an error so assign
1428 // the result here. Caller deallocates all the scratch classes in case of
1429 // an error.
1430 _scratch_classes[i] = scratch_class;
1431
1432 if (HAS_PENDING_EXCEPTION) {
1433 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1434 log_info(redefine, class, load, exceptions)("create_from_stream exception: '%s'", ex_name->as_C_string());
1435 CLEAR_PENDING_EXCEPTION;
1436
1437 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) {
1438 return JVMTI_ERROR_UNSUPPORTED_VERSION;
1439 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) {
1440 return JVMTI_ERROR_INVALID_CLASS_FORMAT;
1441 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) {
1442 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION;
1443 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
1444 // The message will be "XXX (wrong name: YYY)"
1445 return JVMTI_ERROR_NAMES_DONT_MATCH;
1446 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1447 return JVMTI_ERROR_OUT_OF_MEMORY;
1448 } else { // Just in case more exceptions can be thrown..
1449 return JVMTI_ERROR_FAILS_VERIFICATION;
1450 }
1451 }
1452
1453 // Ensure class is linked before redefine
1454 if (!the_class->is_linked()) {
1455 the_class->link_class(THREAD);
1456 if (HAS_PENDING_EXCEPTION) {
1457 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1458 oop message = java_lang_Throwable::message(PENDING_EXCEPTION);
1459 if (message != nullptr) {
1460 char* ex_msg = java_lang_String::as_utf8_string(message);
1461 log_info(redefine, class, load, exceptions)("link_class exception: '%s %s'",
1462 ex_name->as_C_string(), ex_msg);
1463 } else {
1464 log_info(redefine, class, load, exceptions)("link_class exception: '%s'",
1465 ex_name->as_C_string());
1466 }
1467 CLEAR_PENDING_EXCEPTION;
1468 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1469 return JVMTI_ERROR_OUT_OF_MEMORY;
1470 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
1471 return JVMTI_ERROR_INVALID_CLASS;
1472 } else {
1473 return JVMTI_ERROR_INTERNAL;
1474 }
1475 }
1476 }
1477
1478 // Do the validity checks in compare_and_normalize_class_versions()
1479 // before verifying the byte codes. By doing these checks first, we
1480 // limit the number of functions that require redirection from
1481 // the_class to scratch_class. In particular, we don't have to
1482 // modify JNI GetSuperclass() and thus won't change its performance.
1483 jvmtiError res = compare_and_normalize_class_versions(the_class,
1484 scratch_class);
1485 if (res != JVMTI_ERROR_NONE) {
1486 return res;
1487 }
1488
1489 // verify what the caller passed us
1490 {
1491 // The bug 6214132 caused the verification to fail.
1492 // Information about the_class and scratch_class is temporarily
1493 // recorded into jvmtiThreadState. This data is used to redirect
1494 // the_class to scratch_class in the JVM_* functions called by the
1495 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed
1496 // description.
1497 RedefineVerifyMark rvm(the_class, scratch_class, state);
1498 Verifier::verify(scratch_class, true, THREAD);
1499 }
1500
1501 if (HAS_PENDING_EXCEPTION) {
1502 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1503 log_info(redefine, class, load, exceptions)("verify_byte_codes exception: '%s'", ex_name->as_C_string());
1504 CLEAR_PENDING_EXCEPTION;
1505 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1506 return JVMTI_ERROR_OUT_OF_MEMORY;
1507 } else {
1508 // tell the caller the bytecodes are bad
1509 return JVMTI_ERROR_FAILS_VERIFICATION;
1510 }
1511 }
1512
1513 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD);
1514 if (HAS_PENDING_EXCEPTION) {
1515 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1516 log_info(redefine, class, load, exceptions)("merge_cp_and_rewrite 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
1525 #ifdef ASSERT
1526 {
1527 // verify what we have done during constant pool merging
1528 {
1529 RedefineVerifyMark rvm(the_class, scratch_class, state);
1530 Verifier::verify(scratch_class, true, THREAD);
1531 }
1532
1533 if (HAS_PENDING_EXCEPTION) {
1534 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1535 log_info(redefine, class, load, exceptions)
1536 ("verify_byte_codes post merge-CP exception: '%s'", ex_name->as_C_string());
1537 CLEAR_PENDING_EXCEPTION;
1538 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1539 return JVMTI_ERROR_OUT_OF_MEMORY;
1540 } else {
1541 // tell the caller that constant pool merging screwed up
1542 return JVMTI_ERROR_INTERNAL;
1543 }
1544 }
1545 }
1546 #endif // ASSERT
1547
1548 Rewriter::rewrite(scratch_class, THREAD);
1549 if (!HAS_PENDING_EXCEPTION) {
1550 scratch_class->link_methods(THREAD);
1551 }
1552 if (HAS_PENDING_EXCEPTION) {
1553 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1554 log_info(redefine, class, load, exceptions)
1555 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string());
1556 CLEAR_PENDING_EXCEPTION;
1557 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1558 return JVMTI_ERROR_OUT_OF_MEMORY;
1559 } else {
1560 return JVMTI_ERROR_INTERNAL;
1561 }
1562 }
1563
1564 log_debug(redefine, class, load)
1565 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)", the_class->external_name(), os::available_memory() >> 10);
1566 }
1567
1568 return JVMTI_ERROR_NONE;
1569 }
1570
1571
1572 // Map old_index to new_index as needed. scratch_cp is only needed
1573 // for log calls.
1574 void VM_RedefineClasses::map_index(const constantPoolHandle& scratch_cp,
1575 int old_index, int new_index) {
1576 if (find_new_index(old_index) != 0) {
1577 // old_index is already mapped
1578 return;
1579 }
1580
1581 if (old_index == new_index) {
1582 // no mapping is needed
1583 return;
1584 }
1585
1586 _index_map_p->at_put(old_index, new_index);
1587 _index_map_count++;
1588
1589 log_trace(redefine, class, constantpool)
1590 ("mapped tag %d at index %d to %d", scratch_cp->tag_at(old_index).value(), old_index, new_index);
1591 } // end map_index()
1592
1593
1594 // Map old_index to new_index as needed.
1595 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) {
1596 if (find_new_operand_index(old_index) != -1) {
1597 // old_index is already mapped
1598 return;
1599 }
1600
1601 if (old_index == new_index) {
1602 // no mapping is needed
1603 return;
1604 }
1605
1606 _operands_index_map_p->at_put(old_index, new_index);
1607 _operands_index_map_count++;
1608
1609 log_trace(redefine, class, constantpool)("mapped bootstrap specifier at index %d to %d", old_index, new_index);
1610 } // end map_index()
1611
1612
1613 // Merge old_cp and scratch_cp and return the results of the merge via
1614 // merge_cp_p. The number of entries in *merge_cp_p is returned via
1615 // merge_cp_length_p. The entries in old_cp occupy the same locations
1616 // in *merge_cp_p. Also creates a map of indices from entries in
1617 // scratch_cp to the corresponding entry in *merge_cp_p. Index map
1618 // entries are only created for entries in scratch_cp that occupy a
1619 // different location in *merged_cp_p.
1620 bool VM_RedefineClasses::merge_constant_pools(const constantPoolHandle& old_cp,
1621 const constantPoolHandle& scratch_cp, constantPoolHandle *merge_cp_p,
1622 int *merge_cp_length_p, TRAPS) {
1623
1624 if (merge_cp_p == nullptr) {
1625 assert(false, "caller must provide scratch constantPool");
1626 return false; // robustness
1627 }
1628 if (merge_cp_length_p == nullptr) {
1629 assert(false, "caller must provide scratch CP length");
1630 return false; // robustness
1631 }
1632 // Worst case we need old_cp->length() + scratch_cp()->length(),
1633 // but the caller might be smart so make sure we have at least
1634 // the minimum.
1635 if ((*merge_cp_p)->length() < old_cp->length()) {
1636 assert(false, "merge area too small");
1637 return false; // robustness
1638 }
1639
1640 log_info(redefine, class, constantpool)("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(), scratch_cp->length());
1641
1642 {
1643 // Pass 0:
1644 // The old_cp is copied to *merge_cp_p; this means that any code
1645 // using old_cp does not have to change. This work looks like a
1646 // perfect fit for ConstantPool*::copy_cp_to(), but we need to
1647 // handle one special case:
1648 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass
1649 // This will make verification happy.
1650
1651 int old_i; // index into old_cp
1652
1653 // index zero (0) is not used in constantPools
1654 for (old_i = 1; old_i < old_cp->length(); old_i++) {
1655 // leave debugging crumb
1656 jbyte old_tag = old_cp->tag_at(old_i).value();
1657 switch (old_tag) {
1658 case JVM_CONSTANT_Class:
1659 case JVM_CONSTANT_UnresolvedClass:
1660 // revert the copy to JVM_CONSTANT_UnresolvedClass
1661 // May be resolving while calling this so do the same for
1662 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition)
1663 (*merge_cp_p)->temp_unresolved_klass_at_put(old_i,
1664 old_cp->klass_name_index_at(old_i));
1665 break;
1666
1667 case JVM_CONSTANT_Double:
1668 case JVM_CONSTANT_Long:
1669 // just copy the entry to *merge_cp_p, but double and long take
1670 // two constant pool entries
1671 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i);
1672 old_i++;
1673 break;
1674
1675 default:
1676 // just copy the entry to *merge_cp_p
1677 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i);
1678 break;
1679 }
1680 } // end for each old_cp entry
1681
1682 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_false);
1683 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_false);
1684
1685 // We don't need to sanity check that *merge_cp_length_p is within
1686 // *merge_cp_p bounds since we have the minimum on-entry check above.
1687 (*merge_cp_length_p) = old_i;
1688 }
1689
1690 // merge_cp_len should be the same as old_cp->length() at this point
1691 // so this trace message is really a "warm-and-breathing" message.
1692 log_debug(redefine, class, constantpool)("after pass 0: merge_cp_len=%d", *merge_cp_length_p);
1693
1694 int scratch_i; // index into scratch_cp
1695 {
1696 // Pass 1a:
1697 // Compare scratch_cp entries to the old_cp entries that we have
1698 // already copied to *merge_cp_p. In this pass, we are eliminating
1699 // exact duplicates (matching entry at same index) so we only
1700 // compare entries in the common indice range.
1701 int increment = 1;
1702 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length());
1703 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) {
1704 switch (scratch_cp->tag_at(scratch_i).value()) {
1705 case JVM_CONSTANT_Double:
1706 case JVM_CONSTANT_Long:
1707 // double and long take two constant pool entries
1708 increment = 2;
1709 break;
1710
1711 default:
1712 increment = 1;
1713 break;
1714 }
1715
1716 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p, scratch_i);
1717 if (match) {
1718 // found a match at the same index so nothing more to do
1719 continue;
1720 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i,
1721 *merge_cp_p, scratch_i)) {
1722 // The mismatch in compare_entry_to() above is because of a
1723 // resolved versus unresolved class entry at the same index
1724 // with the same string value. Since Pass 0 reverted any
1725 // class entries to unresolved class entries in *merge_cp_p,
1726 // we go with the unresolved class entry.
1727 continue;
1728 }
1729
1730 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p);
1731 if (found_i != 0) {
1732 guarantee(found_i != scratch_i,
1733 "compare_entry_to() and find_matching_entry() do not agree");
1734
1735 // Found a matching entry somewhere else in *merge_cp_p so
1736 // just need a mapping entry.
1737 map_index(scratch_cp, scratch_i, found_i);
1738 continue;
1739 }
1740
1741 // The find_matching_entry() call above could fail to find a match
1742 // due to a resolved versus unresolved class or string entry situation
1743 // like we solved above with the is_unresolved_*_mismatch() calls.
1744 // However, we would have to call is_unresolved_*_mismatch() over
1745 // all of *merge_cp_p (potentially) and that doesn't seem to be
1746 // worth the time.
1747
1748 // No match found so we have to append this entry and any unique
1749 // referenced entries to *merge_cp_p.
1750 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p);
1751 }
1752 }
1753
1754 log_debug(redefine, class, constantpool)
1755 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1756 *merge_cp_length_p, scratch_i, _index_map_count);
1757
1758 if (scratch_i < scratch_cp->length()) {
1759 // Pass 1b:
1760 // old_cp is smaller than scratch_cp so there are entries in
1761 // scratch_cp that we have not yet processed. We take care of
1762 // those now.
1763 int increment = 1;
1764 for (; scratch_i < scratch_cp->length(); scratch_i += increment) {
1765 switch (scratch_cp->tag_at(scratch_i).value()) {
1766 case JVM_CONSTANT_Double:
1767 case JVM_CONSTANT_Long:
1768 // double and long take two constant pool entries
1769 increment = 2;
1770 break;
1771
1772 default:
1773 increment = 1;
1774 break;
1775 }
1776
1777 int found_i =
1778 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p);
1779 if (found_i != 0) {
1780 // Found a matching entry somewhere else in *merge_cp_p so
1781 // just need a mapping entry.
1782 map_index(scratch_cp, scratch_i, found_i);
1783 continue;
1784 }
1785
1786 // No match found so we have to append this entry and any unique
1787 // referenced entries to *merge_cp_p.
1788 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p);
1789 }
1790
1791 log_debug(redefine, class, constantpool)
1792 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1793 *merge_cp_length_p, scratch_i, _index_map_count);
1794 }
1795 finalize_operands_merge(*merge_cp_p, CHECK_false);
1796
1797 return true;
1798 } // end merge_constant_pools()
1799
1800
1801 // Scoped object to clean up the constant pool(s) created for merging
1802 class MergeCPCleaner {
1803 ClassLoaderData* _loader_data;
1804 ConstantPool* _cp;
1805 ConstantPool* _scratch_cp;
1806 public:
1807 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) :
1808 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(nullptr) {}
1809 ~MergeCPCleaner() {
1810 _loader_data->add_to_deallocate_list(_cp);
1811 if (_scratch_cp != nullptr) {
1812 _loader_data->add_to_deallocate_list(_scratch_cp);
1813 }
1814 }
1815 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; }
1816 };
1817
1818 // Merge constant pools between the_class and scratch_class and
1819 // potentially rewrite bytecodes in scratch_class to use the merged
1820 // constant pool.
1821 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite(
1822 InstanceKlass* the_class, InstanceKlass* scratch_class,
1823 TRAPS) {
1824 // worst case merged constant pool length is old and new combined
1825 int merge_cp_length = the_class->constants()->length()
1826 + scratch_class->constants()->length();
1827
1828 // Constant pools are not easily reused so we allocate a new one
1829 // each time.
1830 // merge_cp is created unsafe for concurrent GC processing. It
1831 // should be marked safe before discarding it. Even though
1832 // garbage, if it crosses a card boundary, it may be scanned
1833 // in order to find the start of the first complete object on the card.
1834 ClassLoaderData* loader_data = the_class->class_loader_data();
1835 ConstantPool* merge_cp_oop =
1836 ConstantPool::allocate(loader_data,
1837 merge_cp_length,
1838 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1839 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop);
1840
1841 HandleMark hm(THREAD); // make sure handles are cleared before
1842 // MergeCPCleaner clears out merge_cp_oop
1843 constantPoolHandle merge_cp(THREAD, merge_cp_oop);
1844
1845 // Get constants() from the old class because it could have been rewritten
1846 // while we were at a safepoint allocating a new constant pool.
1847 constantPoolHandle old_cp(THREAD, the_class->constants());
1848 constantPoolHandle scratch_cp(THREAD, scratch_class->constants());
1849
1850 // If the length changed, the class was redefined out from under us. Return
1851 // an error.
1852 if (merge_cp_length != the_class->constants()->length()
1853 + scratch_class->constants()->length()) {
1854 return JVMTI_ERROR_INTERNAL;
1855 }
1856
1857 // Update the version number of the constant pools (may keep scratch_cp)
1858 merge_cp->increment_and_save_version(old_cp->version());
1859 scratch_cp->increment_and_save_version(old_cp->version());
1860
1861 ResourceMark rm(THREAD);
1862 _index_map_count = 0;
1863 _index_map_p = new intArray(scratch_cp->length(), scratch_cp->length(), -1);
1864
1865 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands());
1866 _operands_index_map_count = 0;
1867 int operands_index_map_len = ConstantPool::operand_array_length(scratch_cp->operands());
1868 _operands_index_map_p = new intArray(operands_index_map_len, operands_index_map_len, -1);
1869
1870 // reference to the cp holder is needed for copy_operands()
1871 merge_cp->set_pool_holder(scratch_class);
1872 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp,
1873 &merge_cp_length, THREAD);
1874 merge_cp->set_pool_holder(nullptr);
1875
1876 if (!result) {
1877 // The merge can fail due to memory allocation failure or due
1878 // to robustness checks.
1879 return JVMTI_ERROR_INTERNAL;
1880 }
1881
1882 // Set dynamic constants attribute from the original CP.
1883 if (old_cp->has_dynamic_constant()) {
1884 scratch_cp->set_has_dynamic_constant();
1885 }
1886
1887 log_info(redefine, class, constantpool)("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count);
1888
1889 if (_index_map_count == 0) {
1890 // there is nothing to map between the new and merged constant pools
1891
1892 // Copy attributes from scratch_cp to merge_cp
1893 merge_cp->copy_fields(scratch_cp());
1894
1895 if (old_cp->length() == scratch_cp->length()) {
1896 // The old and new constant pools are the same length and the
1897 // index map is empty. This means that the three constant pools
1898 // are equivalent (but not the same). Unfortunately, the new
1899 // constant pool has not gone through link resolution nor have
1900 // the new class bytecodes gone through constant pool cache
1901 // rewriting so we can't use the old constant pool with the new
1902 // class.
1903
1904 // toss the merged constant pool at return
1905 } else if (old_cp->length() < scratch_cp->length()) {
1906 // The old constant pool has fewer entries than the new constant
1907 // pool and the index map is empty. This means the new constant
1908 // pool is a superset of the old constant pool. However, the old
1909 // class bytecodes have already gone through constant pool cache
1910 // rewriting so we can't use the new constant pool with the old
1911 // class.
1912
1913 // toss the merged constant pool at return
1914 } else {
1915 // The old constant pool has more entries than the new constant
1916 // pool and the index map is empty. This means that both the old
1917 // and merged constant pools are supersets of the new constant
1918 // pool.
1919
1920 // Replace the new constant pool with a shrunken copy of the
1921 // merged constant pool
1922 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1923 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1924 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1925 // It can't be cleaned up while there are handles to it.
1926 cp_cleaner.add_scratch_cp(scratch_cp());
1927 }
1928 } else {
1929 if (log_is_enabled(Trace, redefine, class, constantpool)) {
1930 // don't want to loop unless we are tracing
1931 int count = 0;
1932 for (int i = 1; i < _index_map_p->length(); i++) {
1933 int value = _index_map_p->at(i);
1934
1935 if (value != -1) {
1936 log_trace(redefine, class, constantpool)("index_map[%d]: old=%d new=%d", count, i, value);
1937 count++;
1938 }
1939 }
1940 }
1941
1942 // We have entries mapped between the new and merged constant pools
1943 // so we have to rewrite some constant pool references.
1944 if (!rewrite_cp_refs(scratch_class)) {
1945 return JVMTI_ERROR_INTERNAL;
1946 }
1947
1948 // Copy attributes from scratch_cp to merge_cp (should be done after rewrite_cp_refs())
1949 merge_cp->copy_fields(scratch_cp());
1950
1951 // Replace the new constant pool with a shrunken copy of the
1952 // merged constant pool so now the rewritten bytecodes have
1953 // valid references; the previous new constant pool will get
1954 // GCed.
1955 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1956 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1957 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1958 // It can't be cleaned up while there are handles to it.
1959 cp_cleaner.add_scratch_cp(scratch_cp());
1960 }
1961
1962 return JVMTI_ERROR_NONE;
1963 } // end merge_cp_and_rewrite()
1964
1965
1966 // Rewrite constant pool references in klass scratch_class.
1967 bool VM_RedefineClasses::rewrite_cp_refs(InstanceKlass* scratch_class) {
1968
1969 // rewrite constant pool references in the nest attributes:
1970 if (!rewrite_cp_refs_in_nest_attributes(scratch_class)) {
1971 // propagate failure back to caller
1972 return false;
1973 }
1974
1975 // rewrite constant pool references in the Record attribute:
1976 if (!rewrite_cp_refs_in_record_attribute(scratch_class)) {
1977 // propagate failure back to caller
1978 return false;
1979 }
1980
1981 // rewrite constant pool references in the PermittedSubclasses attribute:
1982 if (!rewrite_cp_refs_in_permitted_subclasses_attribute(scratch_class)) {
1983 // propagate failure back to caller
1984 return false;
1985 }
1986
1987 // rewrite constant pool references in the Preload attribute:
1988 if (!rewrite_cp_refs_in_preload_attribute(scratch_class)) {
1989 // propagate failure back to caller
1990 return false;
1991 }
1992
1993 // rewrite constant pool references in the methods:
1994 if (!rewrite_cp_refs_in_methods(scratch_class)) {
1995 // propagate failure back to caller
1996 return false;
1997 }
1998
1999 // rewrite constant pool references in the class_annotations:
2000 if (!rewrite_cp_refs_in_class_annotations(scratch_class)) {
2001 // propagate failure back to caller
2002 return false;
2003 }
2004
2005 // rewrite constant pool references in the fields_annotations:
2006 if (!rewrite_cp_refs_in_fields_annotations(scratch_class)) {
2007 // propagate failure back to caller
2008 return false;
2009 }
2010
2011 // rewrite constant pool references in the methods_annotations:
2012 if (!rewrite_cp_refs_in_methods_annotations(scratch_class)) {
2013 // propagate failure back to caller
2014 return false;
2015 }
2016
2017 // rewrite constant pool references in the methods_parameter_annotations:
2018 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class)) {
2019 // propagate failure back to caller
2020 return false;
2021 }
2022
2023 // rewrite constant pool references in the methods_default_annotations:
2024 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class)) {
2025 // propagate failure back to caller
2026 return false;
2027 }
2028
2029 // rewrite constant pool references in the class_type_annotations:
2030 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class)) {
2031 // propagate failure back to caller
2032 return false;
2033 }
2034
2035 // rewrite constant pool references in the fields_type_annotations:
2036 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class)) {
2037 // propagate failure back to caller
2038 return false;
2039 }
2040
2041 // rewrite constant pool references in the methods_type_annotations:
2042 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class)) {
2043 // propagate failure back to caller
2044 return false;
2045 }
2046
2047 // There can be type annotations in the Code part of a method_info attribute.
2048 // These annotations are not accessible, even by reflection.
2049 // Currently they are not even parsed by the ClassFileParser.
2050 // If runtime access is added they will also need to be rewritten.
2051
2052 // rewrite source file name index:
2053 u2 source_file_name_idx = scratch_class->source_file_name_index();
2054 if (source_file_name_idx != 0) {
2055 u2 new_source_file_name_idx = find_new_index(source_file_name_idx);
2056 if (new_source_file_name_idx != 0) {
2057 scratch_class->set_source_file_name_index(new_source_file_name_idx);
2058 }
2059 }
2060
2061 // rewrite class generic signature index:
2062 u2 generic_signature_index = scratch_class->generic_signature_index();
2063 if (generic_signature_index != 0) {
2064 u2 new_generic_signature_index = find_new_index(generic_signature_index);
2065 if (new_generic_signature_index != 0) {
2066 scratch_class->set_generic_signature_index(new_generic_signature_index);
2067 }
2068 }
2069
2070 return true;
2071 } // end rewrite_cp_refs()
2072
2073 // Rewrite constant pool references in the NestHost and NestMembers attributes.
2074 bool VM_RedefineClasses::rewrite_cp_refs_in_nest_attributes(
2075 InstanceKlass* scratch_class) {
2076
2077 u2 cp_index = scratch_class->nest_host_index();
2078 if (cp_index != 0) {
2079 scratch_class->set_nest_host_index(find_new_index(cp_index));
2080 }
2081 Array<u2>* nest_members = scratch_class->nest_members();
2082 for (int i = 0; i < nest_members->length(); i++) {
2083 u2 cp_index = nest_members->at(i);
2084 nest_members->at_put(i, find_new_index(cp_index));
2085 }
2086 return true;
2087 }
2088
2089 // Rewrite constant pool references in the Record attribute.
2090 bool VM_RedefineClasses::rewrite_cp_refs_in_record_attribute(InstanceKlass* scratch_class) {
2091 Array<RecordComponent*>* components = scratch_class->record_components();
2092 if (components != nullptr) {
2093 for (int i = 0; i < components->length(); i++) {
2094 RecordComponent* component = components->at(i);
2095 u2 cp_index = component->name_index();
2096 component->set_name_index(find_new_index(cp_index));
2097 cp_index = component->descriptor_index();
2098 component->set_descriptor_index(find_new_index(cp_index));
2099 cp_index = component->generic_signature_index();
2100 if (cp_index != 0) {
2101 component->set_generic_signature_index(find_new_index(cp_index));
2102 }
2103
2104 AnnotationArray* annotations = component->annotations();
2105 if (annotations != nullptr && annotations->length() != 0) {
2106 int byte_i = 0; // byte index into annotations
2107 if (!rewrite_cp_refs_in_annotations_typeArray(annotations, byte_i)) {
2108 log_debug(redefine, class, annotation)("bad record_component_annotations at %d", i);
2109 // propagate failure back to caller
2110 return false;
2111 }
2112 }
2113
2114 AnnotationArray* type_annotations = component->type_annotations();
2115 if (type_annotations != nullptr && type_annotations->length() != 0) {
2116 int byte_i = 0; // byte index into annotations
2117 if (!rewrite_cp_refs_in_annotations_typeArray(type_annotations, byte_i)) {
2118 log_debug(redefine, class, annotation)("bad record_component_type_annotations at %d", i);
2119 // propagate failure back to caller
2120 return false;
2121 }
2122 }
2123 }
2124 }
2125 return true;
2126 }
2127
2128 // Rewrite constant pool references in the PermittedSubclasses attribute.
2129 bool VM_RedefineClasses::rewrite_cp_refs_in_permitted_subclasses_attribute(
2130 InstanceKlass* scratch_class) {
2131
2132 Array<u2>* permitted_subclasses = scratch_class->permitted_subclasses();
2133 assert(permitted_subclasses != nullptr, "unexpected null permitted_subclasses");
2134 for (int i = 0; i < permitted_subclasses->length(); i++) {
2135 u2 cp_index = permitted_subclasses->at(i);
2136 permitted_subclasses->at_put(i, find_new_index(cp_index));
2137 }
2138 return true;
2139 }
2140
2141 // Rewrite constant pool references in the Preload attribute.
2142 bool VM_RedefineClasses::rewrite_cp_refs_in_preload_attribute(
2143 InstanceKlass* scratch_class) {
2144
2145 Array<u2>* preload_classes = scratch_class->preload_classes();
2146 assert(preload_classes != NULL, "unexpected null preload_classes");
2147 for (int i = 0; i < preload_classes->length(); i++) {
2148 u2 cp_index = preload_classes->at(i);
2149 preload_classes->at_put(i, find_new_index(cp_index));
2150 }
2151 return true;
2152 }
2153
2154 // Rewrite constant pool references in the methods.
2155 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(InstanceKlass* scratch_class) {
2156
2157 Array<Method*>* methods = scratch_class->methods();
2158
2159 if (methods == nullptr || methods->length() == 0) {
2160 // no methods so nothing to do
2161 return true;
2162 }
2163
2164 JavaThread* THREAD = JavaThread::current(); // For exception macros.
2165 ExceptionMark em(THREAD);
2166
2167 // rewrite constant pool references in the methods:
2168 for (int i = methods->length() - 1; i >= 0; i--) {
2169 methodHandle method(THREAD, methods->at(i));
2170 methodHandle new_method;
2171 rewrite_cp_refs_in_method(method, &new_method, THREAD);
2172 if (!new_method.is_null()) {
2173 // the method has been replaced so save the new method version
2174 // even in the case of an exception. original method is on the
2175 // deallocation list.
2176 methods->at_put(i, new_method());
2177 }
2178 if (HAS_PENDING_EXCEPTION) {
2179 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
2180 log_info(redefine, class, load, exceptions)("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string());
2181 // Need to clear pending exception here as the super caller sets
2182 // the JVMTI_ERROR_INTERNAL if the returned value is false.
2183 CLEAR_PENDING_EXCEPTION;
2184 return false;
2185 }
2186 }
2187
2188 return true;
2189 }
2190
2191
2192 // Rewrite constant pool references in the specific method. This code
2193 // was adapted from Rewriter::rewrite_method().
2194 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method,
2195 methodHandle *new_method_p, TRAPS) {
2196
2197 *new_method_p = methodHandle(); // default is no new method
2198
2199 // We cache a pointer to the bytecodes here in code_base. If GC
2200 // moves the Method*, then the bytecodes will also move which
2201 // will likely cause a crash. We create a NoSafepointVerifier
2202 // object to detect whether we pass a possible safepoint in this
2203 // code block.
2204 NoSafepointVerifier nsv;
2205
2206 // Bytecodes and their length
2207 address code_base = method->code_base();
2208 int code_length = method->code_size();
2209
2210 int bc_length;
2211 for (int bci = 0; bci < code_length; bci += bc_length) {
2212 address bcp = code_base + bci;
2213 Bytecodes::Code c = (Bytecodes::Code)(*bcp);
2214
2215 bc_length = Bytecodes::length_for(c);
2216 if (bc_length == 0) {
2217 // More complicated bytecodes report a length of zero so
2218 // we have to try again a slightly different way.
2219 bc_length = Bytecodes::length_at(method(), bcp);
2220 }
2221
2222 assert(bc_length != 0, "impossible bytecode length");
2223
2224 switch (c) {
2225 case Bytecodes::_ldc:
2226 {
2227 int cp_index = *(bcp + 1);
2228 int new_index = find_new_index(cp_index);
2229
2230 if (StressLdcRewrite && new_index == 0) {
2231 // If we are stressing ldc -> ldc_w rewriting, then we
2232 // always need a new_index value.
2233 new_index = cp_index;
2234 }
2235 if (new_index != 0) {
2236 // the original index is mapped so we have more work to do
2237 if (!StressLdcRewrite && new_index <= max_jubyte) {
2238 // The new value can still use ldc instead of ldc_w
2239 // unless we are trying to stress ldc -> ldc_w rewriting
2240 log_trace(redefine, class, constantpool)
2241 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index);
2242 *(bcp + 1) = new_index;
2243 } else {
2244 log_trace(redefine, class, constantpool)
2245 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index);
2246 // the new value needs ldc_w instead of ldc
2247 u_char inst_buffer[4]; // max instruction size is 4 bytes
2248 bcp = (address)inst_buffer;
2249 // construct new instruction sequence
2250 *bcp = Bytecodes::_ldc_w;
2251 bcp++;
2252 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w.
2253 // See comment below for difference between put_Java_u2()
2254 // and put_native_u2().
2255 Bytes::put_Java_u2(bcp, new_index);
2256
2257 Relocator rc(method, nullptr /* no RelocatorListener needed */);
2258 methodHandle m;
2259 {
2260 PauseNoSafepointVerifier pnsv(&nsv);
2261
2262 // ldc is 2 bytes and ldc_w is 3 bytes
2263 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK);
2264 }
2265
2266 // return the new method so that the caller can update
2267 // the containing class
2268 *new_method_p = method = m;
2269 // switch our bytecode processing loop from the old method
2270 // to the new method
2271 code_base = method->code_base();
2272 code_length = method->code_size();
2273 bcp = code_base + bci;
2274 c = (Bytecodes::Code)(*bcp);
2275 bc_length = Bytecodes::length_for(c);
2276 assert(bc_length != 0, "sanity check");
2277 } // end we need ldc_w instead of ldc
2278 } // end if there is a mapped index
2279 } break;
2280
2281 // these bytecodes have a two-byte constant pool index
2282 case Bytecodes::_anewarray : // fall through
2283 case Bytecodes::_checkcast : // fall through
2284 case Bytecodes::_getfield : // fall through
2285 case Bytecodes::_getstatic : // fall through
2286 case Bytecodes::_aconst_init : // fall through
2287 case Bytecodes::_withfield : // fall through
2288 case Bytecodes::_instanceof : // fall through
2289 case Bytecodes::_invokedynamic : // fall through
2290 case Bytecodes::_invokeinterface: // fall through
2291 case Bytecodes::_invokespecial : // fall through
2292 case Bytecodes::_invokestatic : // fall through
2293 case Bytecodes::_invokevirtual : // fall through
2294 case Bytecodes::_ldc_w : // fall through
2295 case Bytecodes::_ldc2_w : // fall through
2296 case Bytecodes::_multianewarray : // fall through
2297 case Bytecodes::_new : // fall through
2298 case Bytecodes::_putfield : // fall through
2299 case Bytecodes::_putstatic :
2300 {
2301 address p = bcp + 1;
2302 int cp_index = Bytes::get_Java_u2(p);
2303 int new_index = find_new_index(cp_index);
2304 if (new_index != 0) {
2305 // the original index is mapped so update w/ new value
2306 log_trace(redefine, class, constantpool)
2307 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),p2i(bcp), cp_index, new_index);
2308 // Rewriter::rewrite_method() uses put_native_u2() in this
2309 // situation because it is reusing the constant pool index
2310 // location for a native index into the ConstantPoolCache.
2311 // Since we are updating the constant pool index prior to
2312 // verification and ConstantPoolCache initialization, we
2313 // need to keep the new index in Java byte order.
2314 Bytes::put_Java_u2(p, new_index);
2315 }
2316 } break;
2317 default:
2318 break;
2319 }
2320 } // end for each bytecode
2321 } // end rewrite_cp_refs_in_method()
2322
2323
2324 // Rewrite constant pool references in the class_annotations field.
2325 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(InstanceKlass* scratch_class) {
2326
2327 AnnotationArray* class_annotations = scratch_class->class_annotations();
2328 if (class_annotations == nullptr || class_annotations->length() == 0) {
2329 // no class_annotations so nothing to do
2330 return true;
2331 }
2332
2333 log_debug(redefine, class, annotation)("class_annotations length=%d", class_annotations->length());
2334
2335 int byte_i = 0; // byte index into class_annotations
2336 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i);
2337 }
2338
2339
2340 // Rewrite constant pool references in an annotations typeArray. This
2341 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute
2342 // that is described in section 4.8.15 of the 2nd-edition of the VM spec:
2343 //
2344 // annotations_typeArray {
2345 // u2 num_annotations;
2346 // annotation annotations[num_annotations];
2347 // }
2348 //
2349 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray(
2350 AnnotationArray* annotations_typeArray, int &byte_i_ref) {
2351
2352 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2353 // not enough room for num_annotations field
2354 log_debug(redefine, class, annotation)("length() is too small for num_annotations field");
2355 return false;
2356 }
2357
2358 u2 num_annotations = Bytes::get_Java_u2((address)
2359 annotations_typeArray->adr_at(byte_i_ref));
2360 byte_i_ref += 2;
2361
2362 log_debug(redefine, class, annotation)("num_annotations=%d", num_annotations);
2363
2364 int calc_num_annotations = 0;
2365 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
2366 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, byte_i_ref)) {
2367 log_debug(redefine, class, annotation)("bad annotation_struct at %d", calc_num_annotations);
2368 // propagate failure back to caller
2369 return false;
2370 }
2371 }
2372 assert(num_annotations == calc_num_annotations, "sanity check");
2373
2374 return true;
2375 } // end rewrite_cp_refs_in_annotations_typeArray()
2376
2377
2378 // Rewrite constant pool references in the annotation struct portion of
2379 // an annotations_typeArray. This "structure" is from section 4.8.15 of
2380 // the 2nd-edition of the VM spec:
2381 //
2382 // struct annotation {
2383 // u2 type_index;
2384 // u2 num_element_value_pairs;
2385 // {
2386 // u2 element_name_index;
2387 // element_value value;
2388 // } element_value_pairs[num_element_value_pairs];
2389 // }
2390 //
2391 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct(
2392 AnnotationArray* annotations_typeArray, int &byte_i_ref) {
2393 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) {
2394 // not enough room for smallest annotation_struct
2395 log_debug(redefine, class, annotation)("length() is too small for annotation_struct");
2396 return false;
2397 }
2398
2399 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray,
2400 byte_i_ref, "type_index");
2401
2402 u2 num_element_value_pairs = Bytes::get_Java_u2((address)
2403 annotations_typeArray->adr_at(byte_i_ref));
2404 byte_i_ref += 2;
2405
2406 log_debug(redefine, class, annotation)
2407 ("type_index=%d num_element_value_pairs=%d", type_index, num_element_value_pairs);
2408
2409 int calc_num_element_value_pairs = 0;
2410 for (; calc_num_element_value_pairs < num_element_value_pairs;
2411 calc_num_element_value_pairs++) {
2412 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2413 // not enough room for another element_name_index, let alone
2414 // the rest of another component
2415 log_debug(redefine, class, annotation)("length() is too small for element_name_index");
2416 return false;
2417 }
2418
2419 u2 element_name_index = rewrite_cp_ref_in_annotation_data(
2420 annotations_typeArray, byte_i_ref,
2421 "element_name_index");
2422
2423 log_debug(redefine, class, annotation)("element_name_index=%d", element_name_index);
2424
2425 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, byte_i_ref)) {
2426 log_debug(redefine, class, annotation)("bad element_value at %d", calc_num_element_value_pairs);
2427 // propagate failure back to caller
2428 return false;
2429 }
2430 } // end for each component
2431 assert(num_element_value_pairs == calc_num_element_value_pairs,
2432 "sanity check");
2433
2434 return true;
2435 } // end rewrite_cp_refs_in_annotation_struct()
2436
2437
2438 // Rewrite a constant pool reference at the current position in
2439 // annotations_typeArray if needed. Returns the original constant
2440 // pool reference if a rewrite was not needed or the new constant
2441 // pool reference if a rewrite was needed.
2442 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data(
2443 AnnotationArray* annotations_typeArray, int &byte_i_ref,
2444 const char * trace_mesg) {
2445
2446 address cp_index_addr = (address)
2447 annotations_typeArray->adr_at(byte_i_ref);
2448 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr);
2449 u2 new_cp_index = find_new_index(old_cp_index);
2450 if (new_cp_index != 0) {
2451 log_debug(redefine, class, annotation)("mapped old %s=%d", trace_mesg, old_cp_index);
2452 Bytes::put_Java_u2(cp_index_addr, new_cp_index);
2453 old_cp_index = new_cp_index;
2454 }
2455 byte_i_ref += 2;
2456 return old_cp_index;
2457 }
2458
2459
2460 // Rewrite constant pool references in the element_value portion of an
2461 // annotations_typeArray. This "structure" is from section 4.8.15.1 of
2462 // the 2nd-edition of the VM spec:
2463 //
2464 // struct element_value {
2465 // u1 tag;
2466 // union {
2467 // u2 const_value_index;
2468 // {
2469 // u2 type_name_index;
2470 // u2 const_name_index;
2471 // } enum_const_value;
2472 // u2 class_info_index;
2473 // annotation annotation_value;
2474 // struct {
2475 // u2 num_values;
2476 // element_value values[num_values];
2477 // } array_value;
2478 // } value;
2479 // }
2480 //
2481 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value(
2482 AnnotationArray* annotations_typeArray, int &byte_i_ref) {
2483
2484 if ((byte_i_ref + 1) > annotations_typeArray->length()) {
2485 // not enough room for a tag let alone the rest of an element_value
2486 log_debug(redefine, class, annotation)("length() is too small for a tag");
2487 return false;
2488 }
2489
2490 u1 tag = annotations_typeArray->at(byte_i_ref);
2491 byte_i_ref++;
2492 log_debug(redefine, class, annotation)("tag='%c'", tag);
2493
2494 switch (tag) {
2495 // These BaseType tag values are from Table 4.2 in VM spec:
2496 case JVM_SIGNATURE_BYTE:
2497 case JVM_SIGNATURE_CHAR:
2498 case JVM_SIGNATURE_DOUBLE:
2499 case JVM_SIGNATURE_FLOAT:
2500 case JVM_SIGNATURE_INT:
2501 case JVM_SIGNATURE_LONG:
2502 case JVM_SIGNATURE_SHORT:
2503 case JVM_SIGNATURE_BOOLEAN:
2504
2505 // The remaining tag values are from Table 4.8 in the 2nd-edition of
2506 // the VM spec:
2507 case 's':
2508 {
2509 // For the above tag values (including the BaseType values),
2510 // value.const_value_index is right union field.
2511
2512 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2513 // not enough room for a const_value_index
2514 log_debug(redefine, class, annotation)("length() is too small for a const_value_index");
2515 return false;
2516 }
2517
2518 u2 const_value_index = rewrite_cp_ref_in_annotation_data(
2519 annotations_typeArray, byte_i_ref,
2520 "const_value_index");
2521
2522 log_debug(redefine, class, annotation)("const_value_index=%d", const_value_index);
2523 } break;
2524
2525 case 'e':
2526 {
2527 // for the above tag value, value.enum_const_value is right union field
2528
2529 if ((byte_i_ref + 4) > annotations_typeArray->length()) {
2530 // not enough room for a enum_const_value
2531 log_debug(redefine, class, annotation)("length() is too small for a enum_const_value");
2532 return false;
2533 }
2534
2535 u2 type_name_index = rewrite_cp_ref_in_annotation_data(
2536 annotations_typeArray, byte_i_ref,
2537 "type_name_index");
2538
2539 u2 const_name_index = rewrite_cp_ref_in_annotation_data(
2540 annotations_typeArray, byte_i_ref,
2541 "const_name_index");
2542
2543 log_debug(redefine, class, annotation)
2544 ("type_name_index=%d const_name_index=%d", type_name_index, const_name_index);
2545 } break;
2546
2547 case 'c':
2548 {
2549 // for the above tag value, value.class_info_index is right union field
2550
2551 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2552 // not enough room for a class_info_index
2553 log_debug(redefine, class, annotation)("length() is too small for a class_info_index");
2554 return false;
2555 }
2556
2557 u2 class_info_index = rewrite_cp_ref_in_annotation_data(
2558 annotations_typeArray, byte_i_ref,
2559 "class_info_index");
2560
2561 log_debug(redefine, class, annotation)("class_info_index=%d", class_info_index);
2562 } break;
2563
2564 case '@':
2565 // For the above tag value, value.attr_value is the right union
2566 // field. This is a nested annotation.
2567 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, byte_i_ref)) {
2568 // propagate failure back to caller
2569 return false;
2570 }
2571 break;
2572
2573 case JVM_SIGNATURE_ARRAY:
2574 {
2575 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2576 // not enough room for a num_values field
2577 log_debug(redefine, class, annotation)("length() is too small for a num_values field");
2578 return false;
2579 }
2580
2581 // For the above tag value, value.array_value is the right union
2582 // field. This is an array of nested element_value.
2583 u2 num_values = Bytes::get_Java_u2((address)
2584 annotations_typeArray->adr_at(byte_i_ref));
2585 byte_i_ref += 2;
2586 log_debug(redefine, class, annotation)("num_values=%d", num_values);
2587
2588 int calc_num_values = 0;
2589 for (; calc_num_values < num_values; calc_num_values++) {
2590 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, byte_i_ref)) {
2591 log_debug(redefine, class, annotation)("bad nested element_value at %d", calc_num_values);
2592 // propagate failure back to caller
2593 return false;
2594 }
2595 }
2596 assert(num_values == calc_num_values, "sanity check");
2597 } break;
2598
2599 default:
2600 log_debug(redefine, class, annotation)("bad tag=0x%x", tag);
2601 return false;
2602 } // end decode tag field
2603
2604 return true;
2605 } // end rewrite_cp_refs_in_element_value()
2606
2607
2608 // Rewrite constant pool references in a fields_annotations field.
2609 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations(
2610 InstanceKlass* scratch_class) {
2611
2612 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations();
2613
2614 if (fields_annotations == nullptr || fields_annotations->length() == 0) {
2615 // no fields_annotations so nothing to do
2616 return true;
2617 }
2618
2619 log_debug(redefine, class, annotation)("fields_annotations length=%d", fields_annotations->length());
2620
2621 for (int i = 0; i < fields_annotations->length(); i++) {
2622 AnnotationArray* field_annotations = fields_annotations->at(i);
2623 if (field_annotations == nullptr || field_annotations->length() == 0) {
2624 // this field does not have any annotations so skip it
2625 continue;
2626 }
2627
2628 int byte_i = 0; // byte index into field_annotations
2629 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i)) {
2630 log_debug(redefine, class, annotation)("bad field_annotations at %d", i);
2631 // propagate failure back to caller
2632 return false;
2633 }
2634 }
2635
2636 return true;
2637 } // end rewrite_cp_refs_in_fields_annotations()
2638
2639
2640 // Rewrite constant pool references in a methods_annotations field.
2641 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations(
2642 InstanceKlass* scratch_class) {
2643
2644 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2645 Method* m = scratch_class->methods()->at(i);
2646 AnnotationArray* method_annotations = m->constMethod()->method_annotations();
2647
2648 if (method_annotations == nullptr || method_annotations->length() == 0) {
2649 // this method does not have any annotations so skip it
2650 continue;
2651 }
2652
2653 int byte_i = 0; // byte index into method_annotations
2654 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i)) {
2655 log_debug(redefine, class, annotation)("bad method_annotations at %d", i);
2656 // propagate failure back to caller
2657 return false;
2658 }
2659 }
2660
2661 return true;
2662 } // end rewrite_cp_refs_in_methods_annotations()
2663
2664
2665 // Rewrite constant pool references in a methods_parameter_annotations
2666 // field. This "structure" is adapted from the
2667 // RuntimeVisibleParameterAnnotations_attribute described in section
2668 // 4.8.17 of the 2nd-edition of the VM spec:
2669 //
2670 // methods_parameter_annotations_typeArray {
2671 // u1 num_parameters;
2672 // {
2673 // u2 num_annotations;
2674 // annotation annotations[num_annotations];
2675 // } parameter_annotations[num_parameters];
2676 // }
2677 //
2678 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations(
2679 InstanceKlass* scratch_class) {
2680
2681 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2682 Method* m = scratch_class->methods()->at(i);
2683 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations();
2684 if (method_parameter_annotations == nullptr
2685 || method_parameter_annotations->length() == 0) {
2686 // this method does not have any parameter annotations so skip it
2687 continue;
2688 }
2689
2690 if (method_parameter_annotations->length() < 1) {
2691 // not enough room for a num_parameters field
2692 log_debug(redefine, class, annotation)("length() is too small for a num_parameters field at %d", i);
2693 return false;
2694 }
2695
2696 int byte_i = 0; // byte index into method_parameter_annotations
2697
2698 u1 num_parameters = method_parameter_annotations->at(byte_i);
2699 byte_i++;
2700
2701 log_debug(redefine, class, annotation)("num_parameters=%d", num_parameters);
2702
2703 int calc_num_parameters = 0;
2704 for (; calc_num_parameters < num_parameters; calc_num_parameters++) {
2705 if (!rewrite_cp_refs_in_annotations_typeArray(method_parameter_annotations, byte_i)) {
2706 log_debug(redefine, class, annotation)("bad method_parameter_annotations at %d", calc_num_parameters);
2707 // propagate failure back to caller
2708 return false;
2709 }
2710 }
2711 assert(num_parameters == calc_num_parameters, "sanity check");
2712 }
2713
2714 return true;
2715 } // end rewrite_cp_refs_in_methods_parameter_annotations()
2716
2717
2718 // Rewrite constant pool references in a methods_default_annotations
2719 // field. This "structure" is adapted from the AnnotationDefault_attribute
2720 // that is described in section 4.8.19 of the 2nd-edition of the VM spec:
2721 //
2722 // methods_default_annotations_typeArray {
2723 // element_value default_value;
2724 // }
2725 //
2726 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations(
2727 InstanceKlass* scratch_class) {
2728
2729 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2730 Method* m = scratch_class->methods()->at(i);
2731 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations();
2732 if (method_default_annotations == nullptr
2733 || method_default_annotations->length() == 0) {
2734 // this method does not have any default annotations so skip it
2735 continue;
2736 }
2737
2738 int byte_i = 0; // byte index into method_default_annotations
2739
2740 if (!rewrite_cp_refs_in_element_value(
2741 method_default_annotations, byte_i)) {
2742 log_debug(redefine, class, annotation)("bad default element_value at %d", i);
2743 // propagate failure back to caller
2744 return false;
2745 }
2746 }
2747
2748 return true;
2749 } // end rewrite_cp_refs_in_methods_default_annotations()
2750
2751
2752 // Rewrite constant pool references in a class_type_annotations field.
2753 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations(
2754 InstanceKlass* scratch_class) {
2755
2756 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations();
2757 if (class_type_annotations == nullptr || class_type_annotations->length() == 0) {
2758 // no class_type_annotations so nothing to do
2759 return true;
2760 }
2761
2762 log_debug(redefine, class, annotation)("class_type_annotations length=%d", class_type_annotations->length());
2763
2764 int byte_i = 0; // byte index into class_type_annotations
2765 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations,
2766 byte_i, "ClassFile");
2767 } // end rewrite_cp_refs_in_class_type_annotations()
2768
2769
2770 // Rewrite constant pool references in a fields_type_annotations field.
2771 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations(InstanceKlass* scratch_class) {
2772
2773 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations();
2774 if (fields_type_annotations == nullptr || fields_type_annotations->length() == 0) {
2775 // no fields_type_annotations so nothing to do
2776 return true;
2777 }
2778
2779 log_debug(redefine, class, annotation)("fields_type_annotations length=%d", fields_type_annotations->length());
2780
2781 for (int i = 0; i < fields_type_annotations->length(); i++) {
2782 AnnotationArray* field_type_annotations = fields_type_annotations->at(i);
2783 if (field_type_annotations == nullptr || field_type_annotations->length() == 0) {
2784 // this field does not have any annotations so skip it
2785 continue;
2786 }
2787
2788 int byte_i = 0; // byte index into field_type_annotations
2789 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations,
2790 byte_i, "field_info")) {
2791 log_debug(redefine, class, annotation)("bad field_type_annotations at %d", i);
2792 // propagate failure back to caller
2793 return false;
2794 }
2795 }
2796
2797 return true;
2798 } // end rewrite_cp_refs_in_fields_type_annotations()
2799
2800
2801 // Rewrite constant pool references in a methods_type_annotations field.
2802 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations(
2803 InstanceKlass* scratch_class) {
2804
2805 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2806 Method* m = scratch_class->methods()->at(i);
2807 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations();
2808
2809 if (method_type_annotations == nullptr || method_type_annotations->length() == 0) {
2810 // this method does not have any annotations so skip it
2811 continue;
2812 }
2813
2814 log_debug(redefine, class, annotation)("methods type_annotations length=%d", method_type_annotations->length());
2815
2816 int byte_i = 0; // byte index into method_type_annotations
2817 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations,
2818 byte_i, "method_info")) {
2819 log_debug(redefine, class, annotation)("bad method_type_annotations at %d", i);
2820 // propagate failure back to caller
2821 return false;
2822 }
2823 }
2824
2825 return true;
2826 } // end rewrite_cp_refs_in_methods_type_annotations()
2827
2828
2829 // Rewrite constant pool references in a type_annotations
2830 // field. This "structure" is adapted from the
2831 // RuntimeVisibleTypeAnnotations_attribute described in
2832 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2833 //
2834 // type_annotations_typeArray {
2835 // u2 num_annotations;
2836 // type_annotation annotations[num_annotations];
2837 // }
2838 //
2839 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray(
2840 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2841 const char * location_mesg) {
2842
2843 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2844 // not enough room for num_annotations field
2845 log_debug(redefine, class, annotation)("length() is too small for num_annotations field");
2846 return false;
2847 }
2848
2849 u2 num_annotations = Bytes::get_Java_u2((address)
2850 type_annotations_typeArray->adr_at(byte_i_ref));
2851 byte_i_ref += 2;
2852
2853 log_debug(redefine, class, annotation)("num_type_annotations=%d", num_annotations);
2854
2855 int calc_num_annotations = 0;
2856 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
2857 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray,
2858 byte_i_ref, location_mesg)) {
2859 log_debug(redefine, class, annotation)("bad type_annotation_struct at %d", calc_num_annotations);
2860 // propagate failure back to caller
2861 return false;
2862 }
2863 }
2864 assert(num_annotations == calc_num_annotations, "sanity check");
2865
2866 if (byte_i_ref != type_annotations_typeArray->length()) {
2867 log_debug(redefine, class, annotation)
2868 ("read wrong amount of bytes at end of processing type_annotations_typeArray (%d of %d bytes were read)",
2869 byte_i_ref, type_annotations_typeArray->length());
2870 return false;
2871 }
2872
2873 return true;
2874 } // end rewrite_cp_refs_in_type_annotations_typeArray()
2875
2876
2877 // Rewrite constant pool references in a type_annotation
2878 // field. This "structure" is adapted from the
2879 // RuntimeVisibleTypeAnnotations_attribute described in
2880 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2881 //
2882 // type_annotation {
2883 // u1 target_type;
2884 // union {
2885 // type_parameter_target;
2886 // supertype_target;
2887 // type_parameter_bound_target;
2888 // empty_target;
2889 // method_formal_parameter_target;
2890 // throws_target;
2891 // localvar_target;
2892 // catch_target;
2893 // offset_target;
2894 // type_argument_target;
2895 // } target_info;
2896 // type_path target_path;
2897 // annotation anno;
2898 // }
2899 //
2900 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct(
2901 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2902 const char * location_mesg) {
2903
2904 if (!skip_type_annotation_target(type_annotations_typeArray,
2905 byte_i_ref, location_mesg)) {
2906 return false;
2907 }
2908
2909 if (!skip_type_annotation_type_path(type_annotations_typeArray, byte_i_ref)) {
2910 return false;
2911 }
2912
2913 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray, byte_i_ref)) {
2914 return false;
2915 }
2916
2917 return true;
2918 } // end rewrite_cp_refs_in_type_annotation_struct()
2919
2920
2921 // Read, verify and skip over the target_type and target_info part
2922 // so that rewriting can continue in the later parts of the struct.
2923 //
2924 // u1 target_type;
2925 // union {
2926 // type_parameter_target;
2927 // supertype_target;
2928 // type_parameter_bound_target;
2929 // empty_target;
2930 // method_formal_parameter_target;
2931 // throws_target;
2932 // localvar_target;
2933 // catch_target;
2934 // offset_target;
2935 // type_argument_target;
2936 // } target_info;
2937 //
2938 bool VM_RedefineClasses::skip_type_annotation_target(
2939 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2940 const char * location_mesg) {
2941
2942 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2943 // not enough room for a target_type let alone the rest of a type_annotation
2944 log_debug(redefine, class, annotation)("length() is too small for a target_type");
2945 return false;
2946 }
2947
2948 u1 target_type = type_annotations_typeArray->at(byte_i_ref);
2949 byte_i_ref += 1;
2950 log_debug(redefine, class, annotation)("target_type=0x%.2x", target_type);
2951 log_debug(redefine, class, annotation)("location=%s", location_mesg);
2952
2953 // Skip over target_info
2954 switch (target_type) {
2955 case 0x00:
2956 // kind: type parameter declaration of generic class or interface
2957 // location: ClassFile
2958 case 0x01:
2959 // kind: type parameter declaration of generic method or constructor
2960 // location: method_info
2961
2962 {
2963 // struct:
2964 // type_parameter_target {
2965 // u1 type_parameter_index;
2966 // }
2967 //
2968 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2969 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_target");
2970 return false;
2971 }
2972
2973 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2974 byte_i_ref += 1;
2975
2976 log_debug(redefine, class, annotation)("type_parameter_target: type_parameter_index=%d", type_parameter_index);
2977 } break;
2978
2979 case 0x10:
2980 // kind: type in extends clause of class or interface declaration
2981 // or in implements clause of interface declaration
2982 // location: ClassFile
2983
2984 {
2985 // struct:
2986 // supertype_target {
2987 // u2 supertype_index;
2988 // }
2989 //
2990 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2991 log_debug(redefine, class, annotation)("length() is too small for a supertype_target");
2992 return false;
2993 }
2994
2995 u2 supertype_index = Bytes::get_Java_u2((address)
2996 type_annotations_typeArray->adr_at(byte_i_ref));
2997 byte_i_ref += 2;
2998
2999 log_debug(redefine, class, annotation)("supertype_target: supertype_index=%d", supertype_index);
3000 } break;
3001
3002 case 0x11:
3003 // kind: type in bound of type parameter declaration of generic class or interface
3004 // location: ClassFile
3005 case 0x12:
3006 // kind: type in bound of type parameter declaration of generic method or constructor
3007 // location: method_info
3008
3009 {
3010 // struct:
3011 // type_parameter_bound_target {
3012 // u1 type_parameter_index;
3013 // u1 bound_index;
3014 // }
3015 //
3016 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
3017 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_bound_target");
3018 return false;
3019 }
3020
3021 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
3022 byte_i_ref += 1;
3023 u1 bound_index = type_annotations_typeArray->at(byte_i_ref);
3024 byte_i_ref += 1;
3025
3026 log_debug(redefine, class, annotation)
3027 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d", type_parameter_index, bound_index);
3028 } break;
3029
3030 case 0x13:
3031 // kind: type in field declaration
3032 // location: field_info
3033 case 0x14:
3034 // kind: return type of method, or type of newly constructed object
3035 // location: method_info
3036 case 0x15:
3037 // kind: receiver type of method or constructor
3038 // location: method_info
3039
3040 {
3041 // struct:
3042 // empty_target {
3043 // }
3044 //
3045 log_debug(redefine, class, annotation)("empty_target");
3046 } break;
3047
3048 case 0x16:
3049 // kind: type in formal parameter declaration of method, constructor, or lambda expression
3050 // location: method_info
3051
3052 {
3053 // struct:
3054 // formal_parameter_target {
3055 // u1 formal_parameter_index;
3056 // }
3057 //
3058 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
3059 log_debug(redefine, class, annotation)("length() is too small for a formal_parameter_target");
3060 return false;
3061 }
3062
3063 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref);
3064 byte_i_ref += 1;
3065
3066 log_debug(redefine, class, annotation)
3067 ("formal_parameter_target: formal_parameter_index=%d", formal_parameter_index);
3068 } break;
3069
3070 case 0x17:
3071 // kind: type in throws clause of method or constructor
3072 // location: method_info
3073
3074 {
3075 // struct:
3076 // throws_target {
3077 // u2 throws_type_index
3078 // }
3079 //
3080 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
3081 log_debug(redefine, class, annotation)("length() is too small for a throws_target");
3082 return false;
3083 }
3084
3085 u2 throws_type_index = Bytes::get_Java_u2((address)
3086 type_annotations_typeArray->adr_at(byte_i_ref));
3087 byte_i_ref += 2;
3088
3089 log_debug(redefine, class, annotation)("throws_target: throws_type_index=%d", throws_type_index);
3090 } break;
3091
3092 case 0x40:
3093 // kind: type in local variable declaration
3094 // location: Code
3095 case 0x41:
3096 // kind: type in resource variable declaration
3097 // location: Code
3098
3099 {
3100 // struct:
3101 // localvar_target {
3102 // u2 table_length;
3103 // struct {
3104 // u2 start_pc;
3105 // u2 length;
3106 // u2 index;
3107 // } table[table_length];
3108 // }
3109 //
3110 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
3111 // not enough room for a table_length let alone the rest of a localvar_target
3112 log_debug(redefine, class, annotation)("length() is too small for a localvar_target table_length");
3113 return false;
3114 }
3115
3116 u2 table_length = Bytes::get_Java_u2((address)
3117 type_annotations_typeArray->adr_at(byte_i_ref));
3118 byte_i_ref += 2;
3119
3120 log_debug(redefine, class, annotation)("localvar_target: table_length=%d", table_length);
3121
3122 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry
3123 int table_size = table_length * table_struct_size;
3124
3125 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) {
3126 // not enough room for a table
3127 log_debug(redefine, class, annotation)("length() is too small for a table array of length %d", table_length);
3128 return false;
3129 }
3130
3131 // Skip over table
3132 byte_i_ref += table_size;
3133 } break;
3134
3135 case 0x42:
3136 // kind: type in exception parameter declaration
3137 // location: Code
3138
3139 {
3140 // struct:
3141 // catch_target {
3142 // u2 exception_table_index;
3143 // }
3144 //
3145 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
3146 log_debug(redefine, class, annotation)("length() is too small for a catch_target");
3147 return false;
3148 }
3149
3150 u2 exception_table_index = Bytes::get_Java_u2((address)
3151 type_annotations_typeArray->adr_at(byte_i_ref));
3152 byte_i_ref += 2;
3153
3154 log_debug(redefine, class, annotation)("catch_target: exception_table_index=%d", exception_table_index);
3155 } break;
3156
3157 case 0x43:
3158 // kind: type in instanceof expression
3159 // location: Code
3160 case 0x44:
3161 // kind: type in new expression
3162 // location: Code
3163 case 0x45:
3164 // kind: type in method reference expression using ::new
3165 // location: Code
3166 case 0x46:
3167 // kind: type in method reference expression using ::Identifier
3168 // location: Code
3169
3170 {
3171 // struct:
3172 // offset_target {
3173 // u2 offset;
3174 // }
3175 //
3176 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
3177 log_debug(redefine, class, annotation)("length() is too small for a offset_target");
3178 return false;
3179 }
3180
3181 u2 offset = Bytes::get_Java_u2((address)
3182 type_annotations_typeArray->adr_at(byte_i_ref));
3183 byte_i_ref += 2;
3184
3185 log_debug(redefine, class, annotation)("offset_target: offset=%d", offset);
3186 } break;
3187
3188 case 0x47:
3189 // kind: type in cast expression
3190 // location: Code
3191 case 0x48:
3192 // kind: type argument for generic constructor in new expression or
3193 // explicit constructor invocation statement
3194 // location: Code
3195 case 0x49:
3196 // kind: type argument for generic method in method invocation expression
3197 // location: Code
3198 case 0x4A:
3199 // kind: type argument for generic constructor in method reference expression using ::new
3200 // location: Code
3201 case 0x4B:
3202 // kind: type argument for generic method in method reference expression using ::Identifier
3203 // location: Code
3204
3205 {
3206 // struct:
3207 // type_argument_target {
3208 // u2 offset;
3209 // u1 type_argument_index;
3210 // }
3211 //
3212 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) {
3213 log_debug(redefine, class, annotation)("length() is too small for a type_argument_target");
3214 return false;
3215 }
3216
3217 u2 offset = Bytes::get_Java_u2((address)
3218 type_annotations_typeArray->adr_at(byte_i_ref));
3219 byte_i_ref += 2;
3220 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
3221 byte_i_ref += 1;
3222
3223 log_debug(redefine, class, annotation)
3224 ("type_argument_target: offset=%d, type_argument_index=%d", offset, type_argument_index);
3225 } break;
3226
3227 default:
3228 log_debug(redefine, class, annotation)("unknown target_type");
3229 #ifdef ASSERT
3230 ShouldNotReachHere();
3231 #endif
3232 return false;
3233 }
3234
3235 return true;
3236 } // end skip_type_annotation_target()
3237
3238
3239 // Read, verify and skip over the type_path part so that rewriting
3240 // can continue in the later parts of the struct.
3241 //
3242 // type_path {
3243 // u1 path_length;
3244 // {
3245 // u1 type_path_kind;
3246 // u1 type_argument_index;
3247 // } path[path_length];
3248 // }
3249 //
3250 bool VM_RedefineClasses::skip_type_annotation_type_path(
3251 AnnotationArray* type_annotations_typeArray, int &byte_i_ref) {
3252
3253 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
3254 // not enough room for a path_length let alone the rest of the type_path
3255 log_debug(redefine, class, annotation)("length() is too small for a type_path");
3256 return false;
3257 }
3258
3259 u1 path_length = type_annotations_typeArray->at(byte_i_ref);
3260 byte_i_ref += 1;
3261
3262 log_debug(redefine, class, annotation)("type_path: path_length=%d", path_length);
3263
3264 int calc_path_length = 0;
3265 for (; calc_path_length < path_length; calc_path_length++) {
3266 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) {
3267 // not enough room for a path
3268 log_debug(redefine, class, annotation)
3269 ("length() is too small for path entry %d of %d", calc_path_length, path_length);
3270 return false;
3271 }
3272
3273 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref);
3274 byte_i_ref += 1;
3275 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
3276 byte_i_ref += 1;
3277
3278 log_debug(redefine, class, annotation)
3279 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d",
3280 calc_path_length, type_path_kind, type_argument_index);
3281
3282 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) {
3283 // not enough room for a path
3284 log_debug(redefine, class, annotation)("inconsistent type_path values");
3285 return false;
3286 }
3287 }
3288 assert(path_length == calc_path_length, "sanity check");
3289
3290 return true;
3291 } // end skip_type_annotation_type_path()
3292
3293
3294 // Rewrite constant pool references in the method's stackmap table.
3295 // These "structures" are adapted from the StackMapTable_attribute that
3296 // is described in section 4.8.4 of the 6.0 version of the VM spec
3297 // (dated 2005.10.26):
3298 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
3299 //
3300 // stack_map {
3301 // u2 number_of_entries;
3302 // stack_map_frame entries[number_of_entries];
3303 // }
3304 //
3305 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table(
3306 const methodHandle& method) {
3307
3308 if (!method->has_stackmap_table()) {
3309 return;
3310 }
3311
3312 AnnotationArray* stackmap_data = method->stackmap_data();
3313 address stackmap_p = (address)stackmap_data->adr_at(0);
3314 address stackmap_end = stackmap_p + stackmap_data->length();
3315
3316 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries");
3317 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p);
3318 stackmap_p += 2;
3319
3320 log_debug(redefine, class, stackmap)("number_of_entries=%u", number_of_entries);
3321
3322 // walk through each stack_map_frame
3323 u2 calc_number_of_entries = 0;
3324 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) {
3325 // The stack_map_frame structure is a u1 frame_type followed by
3326 // 0 or more bytes of data:
3327 //
3328 // union stack_map_frame {
3329 // same_frame;
3330 // same_locals_1_stack_item_frame;
3331 // same_locals_1_stack_item_frame_extended;
3332 // chop_frame;
3333 // same_frame_extended;
3334 // append_frame;
3335 // full_frame;
3336 // }
3337
3338 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type");
3339 u1 frame_type = *stackmap_p;
3340 stackmap_p++;
3341
3342 // same_frame {
3343 // u1 frame_type = SAME; /* 0-63 */
3344 // }
3345 if (frame_type <= 63) {
3346 // nothing more to do for same_frame
3347 }
3348
3349 // same_locals_1_stack_item_frame {
3350 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */
3351 // verification_type_info stack[1];
3352 // }
3353 else if (frame_type >= 64 && frame_type <= 127) {
3354 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3355 calc_number_of_entries, frame_type);
3356 }
3357
3358 // reserved for future use
3359 else if (frame_type >= 128 && frame_type <= 246) {
3360 // nothing more to do for reserved frame_types
3361 }
3362
3363 // same_locals_1_stack_item_frame_extended {
3364 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */
3365 // u2 offset_delta;
3366 // verification_type_info stack[1];
3367 // }
3368 else if (frame_type == 247) {
3369 stackmap_p += 2;
3370 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3371 calc_number_of_entries, frame_type);
3372 }
3373
3374 // chop_frame {
3375 // u1 frame_type = CHOP; /* 248-250 */
3376 // u2 offset_delta;
3377 // }
3378 else if (frame_type >= 248 && frame_type <= 250) {
3379 stackmap_p += 2;
3380 }
3381
3382 // same_frame_extended {
3383 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/
3384 // u2 offset_delta;
3385 // }
3386 else if (frame_type == 251) {
3387 stackmap_p += 2;
3388 }
3389
3390 // append_frame {
3391 // u1 frame_type = APPEND; /* 252-254 */
3392 // u2 offset_delta;
3393 // verification_type_info locals[frame_type - 251];
3394 // }
3395 else if (frame_type >= 252 && frame_type <= 254) {
3396 assert(stackmap_p + 2 <= stackmap_end,
3397 "no room for offset_delta");
3398 stackmap_p += 2;
3399 u1 len = frame_type - 251;
3400 for (u1 i = 0; i < len; i++) {
3401 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3402 calc_number_of_entries, frame_type);
3403 }
3404 }
3405
3406 // full_frame {
3407 // u1 frame_type = FULL_FRAME; /* 255 */
3408 // u2 offset_delta;
3409 // u2 number_of_locals;
3410 // verification_type_info locals[number_of_locals];
3411 // u2 number_of_stack_items;
3412 // verification_type_info stack[number_of_stack_items];
3413 // }
3414 else if (frame_type == 255) {
3415 assert(stackmap_p + 2 + 2 <= stackmap_end,
3416 "no room for smallest full_frame");
3417 stackmap_p += 2;
3418
3419 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p);
3420 stackmap_p += 2;
3421
3422 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) {
3423 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3424 calc_number_of_entries, frame_type);
3425 }
3426
3427 // Use the largest size for the number_of_stack_items, but only get
3428 // the right number of bytes.
3429 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p);
3430 stackmap_p += 2;
3431
3432 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) {
3433 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3434 calc_number_of_entries, frame_type);
3435 }
3436 }
3437 } // end while there is a stack_map_frame
3438 assert(number_of_entries == calc_number_of_entries, "sanity check");
3439 } // end rewrite_cp_refs_in_stack_map_table()
3440
3441
3442 // Rewrite constant pool references in the verification type info
3443 // portion of the method's stackmap table. These "structures" are
3444 // adapted from the StackMapTable_attribute that is described in
3445 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26):
3446 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
3447 //
3448 // The verification_type_info structure is a u1 tag followed by 0 or
3449 // more bytes of data:
3450 //
3451 // union verification_type_info {
3452 // Top_variable_info;
3453 // Integer_variable_info;
3454 // Float_variable_info;
3455 // Long_variable_info;
3456 // Double_variable_info;
3457 // Null_variable_info;
3458 // UninitializedThis_variable_info;
3459 // Object_variable_info;
3460 // Uninitialized_variable_info;
3461 // }
3462 //
3463 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info(
3464 address& stackmap_p_ref, address stackmap_end, u2 frame_i,
3465 u1 frame_type) {
3466
3467 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag");
3468 u1 tag = *stackmap_p_ref;
3469 stackmap_p_ref++;
3470
3471 switch (tag) {
3472 // Top_variable_info {
3473 // u1 tag = ITEM_Top; /* 0 */
3474 // }
3475 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top
3476 case 0: // fall through
3477
3478 // Integer_variable_info {
3479 // u1 tag = ITEM_Integer; /* 1 */
3480 // }
3481 case ITEM_Integer: // fall through
3482
3483 // Float_variable_info {
3484 // u1 tag = ITEM_Float; /* 2 */
3485 // }
3486 case ITEM_Float: // fall through
3487
3488 // Double_variable_info {
3489 // u1 tag = ITEM_Double; /* 3 */
3490 // }
3491 case ITEM_Double: // fall through
3492
3493 // Long_variable_info {
3494 // u1 tag = ITEM_Long; /* 4 */
3495 // }
3496 case ITEM_Long: // fall through
3497
3498 // Null_variable_info {
3499 // u1 tag = ITEM_Null; /* 5 */
3500 // }
3501 case ITEM_Null: // fall through
3502
3503 // UninitializedThis_variable_info {
3504 // u1 tag = ITEM_UninitializedThis; /* 6 */
3505 // }
3506 case ITEM_UninitializedThis:
3507 // nothing more to do for the above tag types
3508 break;
3509
3510 // Object_variable_info {
3511 // u1 tag = ITEM_Object; /* 7 */
3512 // u2 cpool_index;
3513 // }
3514 case ITEM_Object:
3515 {
3516 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index");
3517 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref);
3518 u2 new_cp_index = find_new_index(cpool_index);
3519 if (new_cp_index != 0) {
3520 log_debug(redefine, class, stackmap)("mapped old cpool_index=%d", cpool_index);
3521 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
3522 cpool_index = new_cp_index;
3523 }
3524 stackmap_p_ref += 2;
3525
3526 log_debug(redefine, class, stackmap)
3527 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i, frame_type, cpool_index);
3528 } break;
3529
3530 // Uninitialized_variable_info {
3531 // u1 tag = ITEM_Uninitialized; /* 8 */
3532 // u2 offset;
3533 // }
3534 case ITEM_Uninitialized:
3535 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset");
3536 stackmap_p_ref += 2;
3537 break;
3538
3539 default:
3540 log_debug(redefine, class, stackmap)("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag);
3541 ShouldNotReachHere();
3542 break;
3543 } // end switch (tag)
3544 } // end rewrite_cp_refs_in_verification_type_info()
3545
3546
3547 // Change the constant pool associated with klass scratch_class to scratch_cp.
3548 // scratch_cp_length elements are copied from scratch_cp to a smaller constant pool
3549 // and the smaller constant pool is associated with scratch_class.
3550 void VM_RedefineClasses::set_new_constant_pool(
3551 ClassLoaderData* loader_data,
3552 InstanceKlass* scratch_class, constantPoolHandle scratch_cp,
3553 int scratch_cp_length, TRAPS) {
3554 assert(scratch_cp->length() >= scratch_cp_length, "sanity check");
3555
3556 // scratch_cp is a merged constant pool and has enough space for a
3557 // worst case merge situation. We want to associate the minimum
3558 // sized constant pool with the klass to save space.
3559 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK);
3560 constantPoolHandle smaller_cp(THREAD, cp);
3561
3562 // preserve version() value in the smaller copy
3563 int version = scratch_cp->version();
3564 assert(version != 0, "sanity check");
3565 smaller_cp->set_version(version);
3566
3567 // attach klass to new constant pool
3568 // reference to the cp holder is needed for copy_operands()
3569 smaller_cp->set_pool_holder(scratch_class);
3570
3571 smaller_cp->copy_fields(scratch_cp());
3572
3573 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
3574 if (HAS_PENDING_EXCEPTION) {
3575 // Exception is handled in the caller
3576 loader_data->add_to_deallocate_list(smaller_cp());
3577 return;
3578 }
3579 scratch_cp = smaller_cp;
3580
3581 // attach new constant pool to klass
3582 scratch_class->set_constants(scratch_cp());
3583 scratch_cp->initialize_unresolved_klasses(loader_data, CHECK);
3584
3585 int i; // for portability
3586
3587 // update each field in klass to use new constant pool indices as needed
3588 int java_fields;
3589 int injected_fields;
3590 bool update_required = false;
3591 GrowableArray<FieldInfo>* fields = FieldInfoStream::create_FieldInfoArray(scratch_class->fieldinfo_stream(), &java_fields, &injected_fields);
3592 for (int i = 0; i < java_fields; i++) {
3593 FieldInfo* fi = fields->adr_at(i);
3594 jshort cur_index = fi->name_index();
3595 jshort new_index = find_new_index(cur_index);
3596 if (new_index != 0) {
3597 log_trace(redefine, class, constantpool)("field-name_index change: %d to %d", cur_index, new_index);
3598 fi->set_name_index(new_index);
3599 update_required = true;
3600 }
3601 cur_index = fi->signature_index();
3602 new_index = find_new_index(cur_index);
3603 if (new_index != 0) {
3604 log_trace(redefine, class, constantpool)("field-signature_index change: %d to %d", cur_index, new_index);
3605 fi->set_signature_index(new_index);
3606 update_required = true;
3607 }
3608 cur_index = fi->initializer_index();
3609 new_index = find_new_index(cur_index);
3610 if (new_index != 0) {
3611 log_trace(redefine, class, constantpool)("field-initval_index change: %d to %d", cur_index, new_index);
3612 fi->set_initializer_index(new_index);
3613 update_required = true;
3614 }
3615 cur_index = fi->generic_signature_index();
3616 new_index = find_new_index(cur_index);
3617 if (new_index != 0) {
3618 log_trace(redefine, class, constantpool)("field-generic_signature change: %d to %d", cur_index, new_index);
3619 fi->set_generic_signature_index(new_index);
3620 update_required = true;
3621 }
3622 }
3623 if (update_required) {
3624 Array<u1>* old_stream = scratch_class->fieldinfo_stream();
3625 assert(fields->length() == (java_fields + injected_fields), "Must be");
3626 Array<u1>* new_fis = FieldInfoStream::create_FieldInfoStream(fields, java_fields, injected_fields, scratch_class->class_loader_data(), CHECK);
3627 scratch_class->set_fieldinfo_stream(new_fis);
3628 MetadataFactory::free_array<u1>(scratch_class->class_loader_data(), old_stream);
3629 }
3630
3631 // Update constant pool indices in the inner classes info to use
3632 // new constant indices as needed. The inner classes info is a
3633 // quadruple:
3634 // (inner_class_info, outer_class_info, inner_name, inner_access_flags)
3635 InnerClassesIterator iter(scratch_class);
3636 for (; !iter.done(); iter.next()) {
3637 int cur_index = iter.inner_class_info_index();
3638 if (cur_index == 0) {
3639 continue; // JVM spec. allows null inner class refs so skip it
3640 }
3641 int new_index = find_new_index(cur_index);
3642 if (new_index != 0) {
3643 log_trace(redefine, class, constantpool)("inner_class_info change: %d to %d", cur_index, new_index);
3644 iter.set_inner_class_info_index(new_index);
3645 }
3646 cur_index = iter.outer_class_info_index();
3647 new_index = find_new_index(cur_index);
3648 if (new_index != 0) {
3649 log_trace(redefine, class, constantpool)("outer_class_info change: %d to %d", cur_index, new_index);
3650 iter.set_outer_class_info_index(new_index);
3651 }
3652 cur_index = iter.inner_name_index();
3653 new_index = find_new_index(cur_index);
3654 if (new_index != 0) {
3655 log_trace(redefine, class, constantpool)("inner_name change: %d to %d", cur_index, new_index);
3656 iter.set_inner_name_index(new_index);
3657 }
3658 } // end for each inner class
3659
3660 // Attach each method in klass to the new constant pool and update
3661 // to use new constant pool indices as needed:
3662 Array<Method*>* methods = scratch_class->methods();
3663 for (i = methods->length() - 1; i >= 0; i--) {
3664 methodHandle method(THREAD, methods->at(i));
3665 method->set_constants(scratch_cp());
3666
3667 int new_index = find_new_index(method->name_index());
3668 if (new_index != 0) {
3669 log_trace(redefine, class, constantpool)
3670 ("method-name_index change: %d to %d", method->name_index(), new_index);
3671 method->set_name_index(new_index);
3672 }
3673 new_index = find_new_index(method->signature_index());
3674 if (new_index != 0) {
3675 log_trace(redefine, class, constantpool)
3676 ("method-signature_index change: %d to %d", method->signature_index(), new_index);
3677 method->set_signature_index(new_index);
3678 }
3679 new_index = find_new_index(method->generic_signature_index());
3680 if (new_index != 0) {
3681 log_trace(redefine, class, constantpool)
3682 ("method-generic_signature_index change: %d to %d", method->generic_signature_index(), new_index);
3683 method->set_generic_signature_index(new_index);
3684 }
3685
3686 // Update constant pool indices in the method's checked exception
3687 // table to use new constant indices as needed.
3688 int cext_length = method->checked_exceptions_length();
3689 if (cext_length > 0) {
3690 CheckedExceptionElement * cext_table =
3691 method->checked_exceptions_start();
3692 for (int j = 0; j < cext_length; j++) {
3693 int cur_index = cext_table[j].class_cp_index;
3694 int new_index = find_new_index(cur_index);
3695 if (new_index != 0) {
3696 log_trace(redefine, class, constantpool)("cext-class_cp_index change: %d to %d", cur_index, new_index);
3697 cext_table[j].class_cp_index = (u2)new_index;
3698 }
3699 } // end for each checked exception table entry
3700 } // end if there are checked exception table entries
3701
3702 // Update each catch type index in the method's exception table
3703 // to use new constant pool indices as needed. The exception table
3704 // holds quadruple entries of the form:
3705 // (beg_bci, end_bci, handler_bci, klass_index)
3706
3707 ExceptionTable ex_table(method());
3708 int ext_length = ex_table.length();
3709
3710 for (int j = 0; j < ext_length; j ++) {
3711 int cur_index = ex_table.catch_type_index(j);
3712 int new_index = find_new_index(cur_index);
3713 if (new_index != 0) {
3714 log_trace(redefine, class, constantpool)("ext-klass_index change: %d to %d", cur_index, new_index);
3715 ex_table.set_catch_type_index(j, new_index);
3716 }
3717 } // end for each exception table entry
3718
3719 // Update constant pool indices in the method's local variable
3720 // table to use new constant indices as needed. The local variable
3721 // table hold sextuple entries of the form:
3722 // (start_pc, length, name_index, descriptor_index, signature_index, slot)
3723 int lvt_length = method->localvariable_table_length();
3724 if (lvt_length > 0) {
3725 LocalVariableTableElement * lv_table =
3726 method->localvariable_table_start();
3727 for (int j = 0; j < lvt_length; j++) {
3728 int cur_index = lv_table[j].name_cp_index;
3729 int new_index = find_new_index(cur_index);
3730 if (new_index != 0) {
3731 log_trace(redefine, class, constantpool)("lvt-name_cp_index change: %d to %d", cur_index, new_index);
3732 lv_table[j].name_cp_index = (u2)new_index;
3733 }
3734 cur_index = lv_table[j].descriptor_cp_index;
3735 new_index = find_new_index(cur_index);
3736 if (new_index != 0) {
3737 log_trace(redefine, class, constantpool)("lvt-descriptor_cp_index change: %d to %d", cur_index, new_index);
3738 lv_table[j].descriptor_cp_index = (u2)new_index;
3739 }
3740 cur_index = lv_table[j].signature_cp_index;
3741 new_index = find_new_index(cur_index);
3742 if (new_index != 0) {
3743 log_trace(redefine, class, constantpool)("lvt-signature_cp_index change: %d to %d", cur_index, new_index);
3744 lv_table[j].signature_cp_index = (u2)new_index;
3745 }
3746 } // end for each local variable table entry
3747 } // end if there are local variable table entries
3748
3749 // Update constant pool indices in the method's method_parameters.
3750 int mp_length = method->method_parameters_length();
3751 if (mp_length > 0) {
3752 MethodParametersElement* elem = method->method_parameters_start();
3753 for (int j = 0; j < mp_length; j++) {
3754 const int cp_index = elem[j].name_cp_index;
3755 const int new_cp_index = find_new_index(cp_index);
3756 if (new_cp_index != 0) {
3757 elem[j].name_cp_index = (u2)new_cp_index;
3758 }
3759 }
3760 }
3761
3762 rewrite_cp_refs_in_stack_map_table(method);
3763 } // end for each method
3764 } // end set_new_constant_pool()
3765
3766
3767 // Unevolving classes may point to methods of the_class directly
3768 // from their constant pool caches, itables, and/or vtables. We
3769 // use the ClassLoaderDataGraph::classes_do() facility and this helper
3770 // to fix up these pointers. MethodData also points to old methods and
3771 // must be cleaned.
3772
3773 // Adjust cpools and vtables closure
3774 void VM_RedefineClasses::AdjustAndCleanMetadata::do_klass(Klass* k) {
3775
3776 // This is a very busy routine. We don't want too much tracing
3777 // printed out.
3778 bool trace_name_printed = false;
3779
3780 // If the class being redefined is java.lang.Object, we need to fix all
3781 // array class vtables also. The _has_redefined_Object flag is global.
3782 // Once the java.lang.Object has been redefined (by the current or one
3783 // of the previous VM_RedefineClasses operations) we have to always
3784 // adjust method entries for array classes.
3785 if (k->is_array_klass() && _has_redefined_Object) {
3786 k->vtable().adjust_method_entries(&trace_name_printed);
3787
3788 } else if (k->is_instance_klass()) {
3789 HandleMark hm(_thread);
3790 InstanceKlass *ik = InstanceKlass::cast(k);
3791
3792 // Clean MethodData of this class's methods so they don't refer to
3793 // old methods that are no longer running.
3794 Array<Method*>* methods = ik->methods();
3795 int num_methods = methods->length();
3796 for (int index = 0; index < num_methods; ++index) {
3797 if (methods->at(index)->method_data() != nullptr) {
3798 methods->at(index)->method_data()->clean_weak_method_links();
3799 }
3800 }
3801
3802 // Adjust all vtables, default methods and itables, to clean out old methods.
3803 ResourceMark rm(_thread);
3804 if (ik->vtable_length() > 0) {
3805 ik->vtable().adjust_method_entries(&trace_name_printed);
3806 ik->adjust_default_methods(&trace_name_printed);
3807 }
3808
3809 if (ik->itable_length() > 0) {
3810 ik->itable().adjust_method_entries(&trace_name_printed);
3811 }
3812
3813 // The constant pools in other classes (other_cp) can refer to
3814 // old methods. We have to update method information in
3815 // other_cp's cache. If other_cp has a previous version, then we
3816 // have to repeat the process for each previous version. The
3817 // constant pool cache holds the Method*s for non-virtual
3818 // methods and for virtual, final methods.
3819 //
3820 // Special case: if the current class is being redefined by the current
3821 // VM_RedefineClasses operation, then new_cp has already been attached
3822 // to the_class and old_cp has already been added as a previous version.
3823 // The new_cp doesn't have any cached references to old methods so it
3824 // doesn't need to be updated and we could optimize by skipping it.
3825 // However, the current class can be marked as being redefined by another
3826 // VM_RedefineClasses operation which has already executed its doit_prologue
3827 // and needs cpcache method entries adjusted. For simplicity, the cpcache
3828 // update is done unconditionally. It should result in doing nothing for
3829 // classes being redefined by the current VM_RedefineClasses operation.
3830 // Method entries in the previous version(s) are adjusted as well.
3831 ConstantPoolCache* cp_cache;
3832
3833 // this klass' constant pool cache may need adjustment
3834 ConstantPool* other_cp = ik->constants();
3835 cp_cache = other_cp->cache();
3836 if (cp_cache != nullptr) {
3837 cp_cache->adjust_method_entries(&trace_name_printed);
3838 }
3839
3840 // the previous versions' constant pool caches may need adjustment
3841 for (InstanceKlass* pv_node = ik->previous_versions();
3842 pv_node != nullptr;
3843 pv_node = pv_node->previous_versions()) {
3844 cp_cache = pv_node->constants()->cache();
3845 if (cp_cache != nullptr) {
3846 cp_cache->adjust_method_entries(&trace_name_printed);
3847 }
3848 }
3849 }
3850 }
3851
3852 void VM_RedefineClasses::update_jmethod_ids() {
3853 for (int j = 0; j < _matching_methods_length; ++j) {
3854 Method* old_method = _matching_old_methods[j];
3855 jmethodID jmid = old_method->find_jmethod_id_or_null();
3856 if (jmid != nullptr) {
3857 // There is a jmethodID, change it to point to the new method
3858 Method* new_method = _matching_new_methods[j];
3859 Method::change_method_associated_with_jmethod_id(jmid, new_method);
3860 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j],
3861 "should be replaced");
3862 }
3863 }
3864 }
3865
3866 int VM_RedefineClasses::check_methods_and_mark_as_obsolete() {
3867 int emcp_method_count = 0;
3868 int obsolete_count = 0;
3869 int old_index = 0;
3870 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
3871 Method* old_method = _matching_old_methods[j];
3872 Method* new_method = _matching_new_methods[j];
3873 Method* old_array_method;
3874
3875 // Maintain an old_index into the _old_methods array by skipping
3876 // deleted methods
3877 while ((old_array_method = _old_methods->at(old_index)) != old_method) {
3878 ++old_index;
3879 }
3880
3881 if (MethodComparator::methods_EMCP(old_method, new_method)) {
3882 // The EMCP definition from JSR-163 requires the bytecodes to be
3883 // the same with the exception of constant pool indices which may
3884 // differ. However, the constants referred to by those indices
3885 // must be the same.
3886 //
3887 // We use methods_EMCP() for comparison since constant pool
3888 // merging can remove duplicate constant pool entries that were
3889 // present in the old method and removed from the rewritten new
3890 // method. A faster binary comparison function would consider the
3891 // old and new methods to be different when they are actually
3892 // EMCP.
3893 //
3894 // The old and new methods are EMCP and you would think that we
3895 // could get rid of one of them here and now and save some space.
3896 // However, the concept of EMCP only considers the bytecodes and
3897 // the constant pool entries in the comparison. Other things,
3898 // e.g., the line number table (LNT) or the local variable table
3899 // (LVT) don't count in the comparison. So the new (and EMCP)
3900 // method can have a new LNT that we need so we can't just
3901 // overwrite the new method with the old method.
3902 //
3903 // When this routine is called, we have already attached the new
3904 // methods to the_class so the old methods are effectively
3905 // overwritten. However, if an old method is still executing,
3906 // then the old method cannot be collected until sometime after
3907 // the old method call has returned. So the overwriting of old
3908 // methods by new methods will save us space except for those
3909 // (hopefully few) old methods that are still executing.
3910 //
3911 // A method refers to a ConstMethod* and this presents another
3912 // possible avenue to space savings. The ConstMethod* in the
3913 // new method contains possibly new attributes (LNT, LVT, etc).
3914 // At first glance, it seems possible to save space by replacing
3915 // the ConstMethod* in the old method with the ConstMethod*
3916 // from the new method. The old and new methods would share the
3917 // same ConstMethod* and we would save the space occupied by
3918 // the old ConstMethod*. However, the ConstMethod* contains
3919 // a back reference to the containing method. Sharing the
3920 // ConstMethod* between two methods could lead to confusion in
3921 // the code that uses the back reference. This would lead to
3922 // brittle code that could be broken in non-obvious ways now or
3923 // in the future.
3924 //
3925 // Another possibility is to copy the ConstMethod* from the new
3926 // method to the old method and then overwrite the new method with
3927 // the old method. Since the ConstMethod* contains the bytecodes
3928 // for the method embedded in the oop, this option would change
3929 // the bytecodes out from under any threads executing the old
3930 // method and make the thread's bcp invalid. Since EMCP requires
3931 // that the bytecodes be the same modulo constant pool indices, it
3932 // is straight forward to compute the correct new bcp in the new
3933 // ConstMethod* from the old bcp in the old ConstMethod*. The
3934 // time consuming part would be searching all the frames in all
3935 // of the threads to find all of the calls to the old method.
3936 //
3937 // It looks like we will have to live with the limited savings
3938 // that we get from effectively overwriting the old methods
3939 // when the new methods are attached to the_class.
3940
3941 // Count number of methods that are EMCP. The method will be marked
3942 // old but not obsolete if it is EMCP.
3943 emcp_method_count++;
3944
3945 // An EMCP method is _not_ obsolete. An obsolete method has a
3946 // different jmethodID than the current method. An EMCP method
3947 // has the same jmethodID as the current method. Having the
3948 // same jmethodID for all EMCP versions of a method allows for
3949 // a consistent view of the EMCP methods regardless of which
3950 // EMCP method you happen to have in hand. For example, a
3951 // breakpoint set in one EMCP method will work for all EMCP
3952 // versions of the method including the current one.
3953 } else {
3954 // mark obsolete methods as such
3955 old_method->set_is_obsolete();
3956 obsolete_count++;
3957
3958 // obsolete methods need a unique idnum so they become new entries in
3959 // the jmethodID cache in InstanceKlass
3960 assert(old_method->method_idnum() == new_method->method_idnum(), "must match");
3961 u2 num = InstanceKlass::cast(_the_class)->next_method_idnum();
3962 if (num != ConstMethod::UNSET_IDNUM) {
3963 old_method->set_method_idnum(num);
3964 }
3965
3966 // With tracing we try not to "yack" too much. The position of
3967 // this trace assumes there are fewer obsolete methods than
3968 // EMCP methods.
3969 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) {
3970 ResourceMark rm;
3971 log_trace(redefine, class, obsolete, mark)
3972 ("mark %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string());
3973 }
3974 }
3975 old_method->set_is_old();
3976 }
3977 for (int i = 0; i < _deleted_methods_length; ++i) {
3978 Method* old_method = _deleted_methods[i];
3979
3980 assert(!old_method->has_vtable_index(),
3981 "cannot delete methods with vtable entries");;
3982
3983 // Mark all deleted methods as old, obsolete and deleted
3984 old_method->set_is_deleted();
3985 old_method->set_is_old();
3986 old_method->set_is_obsolete();
3987 ++obsolete_count;
3988 // With tracing we try not to "yack" too much. The position of
3989 // this trace assumes there are fewer obsolete methods than
3990 // EMCP methods.
3991 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) {
3992 ResourceMark rm;
3993 log_trace(redefine, class, obsolete, mark)
3994 ("mark deleted %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string());
3995 }
3996 }
3997 assert((emcp_method_count + obsolete_count) == _old_methods->length(),
3998 "sanity check");
3999 log_trace(redefine, class, obsolete, mark)("EMCP_cnt=%d, obsolete_cnt=%d", emcp_method_count, obsolete_count);
4000 return emcp_method_count;
4001 }
4002
4003 // This internal class transfers the native function registration from old methods
4004 // to new methods. It is designed to handle both the simple case of unchanged
4005 // native methods and the complex cases of native method prefixes being added and/or
4006 // removed.
4007 // It expects only to be used during the VM_RedefineClasses op (a safepoint).
4008 //
4009 // This class is used after the new methods have been installed in "the_class".
4010 //
4011 // So, for example, the following must be handled. Where 'm' is a method and
4012 // a number followed by an underscore is a prefix.
4013 //
4014 // Old Name New Name
4015 // Simple transfer to new method m -> m
4016 // Add prefix m -> 1_m
4017 // Remove prefix 1_m -> m
4018 // Simultaneous add of prefixes m -> 3_2_1_m
4019 // Simultaneous removal of prefixes 3_2_1_m -> m
4020 // Simultaneous add and remove 1_m -> 2_m
4021 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m
4022 //
4023 class TransferNativeFunctionRegistration {
4024 private:
4025 InstanceKlass* the_class;
4026 int prefix_count;
4027 char** prefixes;
4028
4029 // Recursively search the binary tree of possibly prefixed method names.
4030 // Iteration could be used if all agents were well behaved. Full tree walk is
4031 // more resilent to agents not cleaning up intermediate methods.
4032 // Branch at each depth in the binary tree is:
4033 // (1) without the prefix.
4034 // (2) with the prefix.
4035 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
4036 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len,
4037 Symbol* signature) {
4038 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len);
4039 if (name_symbol != nullptr) {
4040 Method* method = the_class->lookup_method(name_symbol, signature);
4041 if (method != nullptr) {
4042 // Even if prefixed, intermediate methods must exist.
4043 if (method->is_native()) {
4044 // Wahoo, we found a (possibly prefixed) version of the method, return it.
4045 return method;
4046 }
4047 if (depth < prefix_count) {
4048 // Try applying further prefixes (other than this one).
4049 method = search_prefix_name_space(depth+1, name_str, name_len, signature);
4050 if (method != nullptr) {
4051 return method; // found
4052 }
4053
4054 // Try adding this prefix to the method name and see if it matches
4055 // another method name.
4056 char* prefix = prefixes[depth];
4057 size_t prefix_len = strlen(prefix);
4058 size_t trial_len = name_len + prefix_len;
4059 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
4060 strcpy(trial_name_str, prefix);
4061 strcat(trial_name_str, name_str);
4062 method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
4063 signature);
4064 if (method != nullptr) {
4065 // If found along this branch, it was prefixed, mark as such
4066 method->set_is_prefixed_native();
4067 return method; // found
4068 }
4069 }
4070 }
4071 }
4072 return nullptr; // This whole branch bore nothing
4073 }
4074
4075 // Return the method name with old prefixes stripped away.
4076 char* method_name_without_prefixes(Method* method) {
4077 Symbol* name = method->name();
4078 char* name_str = name->as_utf8();
4079
4080 // Old prefixing may be defunct, strip prefixes, if any.
4081 for (int i = prefix_count-1; i >= 0; i--) {
4082 char* prefix = prefixes[i];
4083 size_t prefix_len = strlen(prefix);
4084 if (strncmp(prefix, name_str, prefix_len) == 0) {
4085 name_str += prefix_len;
4086 }
4087 }
4088 return name_str;
4089 }
4090
4091 // Strip any prefixes off the old native method, then try to find a
4092 // (possibly prefixed) new native that matches it.
4093 Method* strip_and_search_for_new_native(Method* method) {
4094 ResourceMark rm;
4095 char* name_str = method_name_without_prefixes(method);
4096 return search_prefix_name_space(0, name_str, strlen(name_str),
4097 method->signature());
4098 }
4099
4100 public:
4101
4102 // Construct a native method transfer processor for this class.
4103 TransferNativeFunctionRegistration(InstanceKlass* _the_class) {
4104 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
4105
4106 the_class = _the_class;
4107 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
4108 }
4109
4110 // Attempt to transfer any of the old or deleted methods that are native
4111 void transfer_registrations(Method** old_methods, int methods_length) {
4112 for (int j = 0; j < methods_length; j++) {
4113 Method* old_method = old_methods[j];
4114
4115 if (old_method->is_native() && old_method->has_native_function()) {
4116 Method* new_method = strip_and_search_for_new_native(old_method);
4117 if (new_method != nullptr) {
4118 // Actually set the native function in the new method.
4119 // Redefine does not send events (except CFLH), certainly not this
4120 // behind the scenes re-registration.
4121 new_method->set_native_function(old_method->native_function(),
4122 !Method::native_bind_event_is_interesting);
4123 }
4124 }
4125 }
4126 }
4127 };
4128
4129 // Don't lose the association between a native method and its JNI function.
4130 void VM_RedefineClasses::transfer_old_native_function_registrations(InstanceKlass* the_class) {
4131 TransferNativeFunctionRegistration transfer(the_class);
4132 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length);
4133 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length);
4134 }
4135
4136 // Deoptimize all compiled code that depends on the classes redefined.
4137 //
4138 // If the can_redefine_classes capability is obtained in the onload
4139 // phase then the compiler has recorded all dependencies from startup.
4140 // In that case we need only deoptimize and throw away all compiled code
4141 // that depends on the class.
4142 //
4143 // If can_redefine_classes is obtained sometime after the onload
4144 // phase then the dependency information may be incomplete. In that case
4145 // the first call to RedefineClasses causes all compiled code to be
4146 // thrown away. As can_redefine_classes has been obtained then
4147 // all future compilations will record dependencies so second and
4148 // subsequent calls to RedefineClasses need only throw away code
4149 // that depends on the class.
4150 //
4151
4152 void VM_RedefineClasses::flush_dependent_code() {
4153 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
4154
4155 DeoptimizationScope deopt_scope;
4156
4157 // This is the first redefinition, mark all the nmethods for deoptimization
4158 if (!JvmtiExport::all_dependencies_are_recorded()) {
4159 CodeCache::mark_all_nmethods_for_evol_deoptimization(&deopt_scope);
4160 log_debug(redefine, class, nmethod)("Marked all nmethods for deopt");
4161 } else {
4162 CodeCache::mark_dependents_for_evol_deoptimization(&deopt_scope);
4163 log_debug(redefine, class, nmethod)("Marked dependent nmethods for deopt");
4164 }
4165
4166 deopt_scope.deoptimize_marked();
4167
4168 // From now on we know that the dependency information is complete
4169 JvmtiExport::set_all_dependencies_are_recorded(true);
4170 }
4171
4172 void VM_RedefineClasses::compute_added_deleted_matching_methods() {
4173 Method* old_method;
4174 Method* new_method;
4175
4176 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
4177 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
4178 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length());
4179 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
4180
4181 _matching_methods_length = 0;
4182 _deleted_methods_length = 0;
4183 _added_methods_length = 0;
4184
4185 int nj = 0;
4186 int oj = 0;
4187 while (true) {
4188 if (oj >= _old_methods->length()) {
4189 if (nj >= _new_methods->length()) {
4190 break; // we've looked at everything, done
4191 }
4192 // New method at the end
4193 new_method = _new_methods->at(nj);
4194 _added_methods[_added_methods_length++] = new_method;
4195 ++nj;
4196 } else if (nj >= _new_methods->length()) {
4197 // Old method, at the end, is deleted
4198 old_method = _old_methods->at(oj);
4199 _deleted_methods[_deleted_methods_length++] = old_method;
4200 ++oj;
4201 } else {
4202 old_method = _old_methods->at(oj);
4203 new_method = _new_methods->at(nj);
4204 if (old_method->name() == new_method->name()) {
4205 if (old_method->signature() == new_method->signature()) {
4206 _matching_old_methods[_matching_methods_length ] = old_method;
4207 _matching_new_methods[_matching_methods_length++] = new_method;
4208 ++nj;
4209 ++oj;
4210 } else {
4211 // added overloaded have already been moved to the end,
4212 // so this is a deleted overloaded method
4213 _deleted_methods[_deleted_methods_length++] = old_method;
4214 ++oj;
4215 }
4216 } else { // names don't match
4217 if (old_method->name()->fast_compare(new_method->name()) > 0) {
4218 // new method
4219 _added_methods[_added_methods_length++] = new_method;
4220 ++nj;
4221 } else {
4222 // deleted method
4223 _deleted_methods[_deleted_methods_length++] = old_method;
4224 ++oj;
4225 }
4226 }
4227 }
4228 }
4229 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
4230 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
4231 }
4232
4233
4234 void VM_RedefineClasses::swap_annotations(InstanceKlass* the_class,
4235 InstanceKlass* scratch_class) {
4236 // Swap annotation fields values
4237 Annotations* old_annotations = the_class->annotations();
4238 the_class->set_annotations(scratch_class->annotations());
4239 scratch_class->set_annotations(old_annotations);
4240 }
4241
4242
4243 // Install the redefinition of a class:
4244 // - house keeping (flushing breakpoints and caches, deoptimizing
4245 // dependent compiled code)
4246 // - replacing parts in the_class with parts from scratch_class
4247 // - adding a weak reference to track the obsolete but interesting
4248 // parts of the_class
4249 // - adjusting constant pool caches and vtables in other classes
4250 // that refer to methods in the_class. These adjustments use the
4251 // ClassLoaderDataGraph::classes_do() facility which only allows
4252 // a helper method to be specified. The interesting parameters
4253 // that we would like to pass to the helper method are saved in
4254 // static global fields in the VM operation.
4255 void VM_RedefineClasses::redefine_single_class(Thread* current, jclass the_jclass,
4256 InstanceKlass* scratch_class) {
4257
4258 HandleMark hm(current); // make sure handles from this call are freed
4259
4260 if (log_is_enabled(Info, redefine, class, timer)) {
4261 _timer_rsc_phase1.start();
4262 }
4263
4264 InstanceKlass* the_class = get_ik(the_jclass);
4265
4266 // Set a flag to control and optimize adjusting method entries
4267 _has_redefined_Object |= the_class == vmClasses::Object_klass();
4268
4269 // Remove all breakpoints in methods of this class
4270 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
4271 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class);
4272
4273 _old_methods = the_class->methods();
4274 _new_methods = scratch_class->methods();
4275 _the_class = the_class;
4276 compute_added_deleted_matching_methods();
4277 update_jmethod_ids();
4278
4279 _any_class_has_resolved_methods = the_class->has_resolved_methods() || _any_class_has_resolved_methods;
4280
4281 // Attach new constant pool to the original klass. The original
4282 // klass still refers to the old constant pool (for now).
4283 scratch_class->constants()->set_pool_holder(the_class);
4284
4285 #if 0
4286 // In theory, with constant pool merging in place we should be able
4287 // to save space by using the new, merged constant pool in place of
4288 // the old constant pool(s). By "pool(s)" I mean the constant pool in
4289 // the klass version we are replacing now and any constant pool(s) in
4290 // previous versions of klass. Nice theory, doesn't work in practice.
4291 // When this code is enabled, even simple programs throw NullPointer
4292 // exceptions. I'm guessing that this is caused by some constant pool
4293 // cache difference between the new, merged constant pool and the
4294 // constant pool that was just being used by the klass. I'm keeping
4295 // this code around to archive the idea, but the code has to remain
4296 // disabled for now.
4297
4298 // Attach each old method to the new constant pool. This can be
4299 // done here since we are past the bytecode verification and
4300 // constant pool optimization phases.
4301 for (int i = _old_methods->length() - 1; i >= 0; i--) {
4302 Method* method = _old_methods->at(i);
4303 method->set_constants(scratch_class->constants());
4304 }
4305
4306 // NOTE: this doesn't work because you can redefine the same class in two
4307 // threads, each getting their own constant pool data appended to the
4308 // original constant pool. In order for the new methods to work when they
4309 // become old methods, they need to keep their updated copy of the constant pool.
4310
4311 {
4312 // walk all previous versions of the klass
4313 InstanceKlass *ik = the_class;
4314 PreviousVersionWalker pvw(ik);
4315 do {
4316 ik = pvw.next_previous_version();
4317 if (ik != nullptr) {
4318
4319 // attach previous version of klass to the new constant pool
4320 ik->set_constants(scratch_class->constants());
4321
4322 // Attach each method in the previous version of klass to the
4323 // new constant pool
4324 Array<Method*>* prev_methods = ik->methods();
4325 for (int i = prev_methods->length() - 1; i >= 0; i--) {
4326 Method* method = prev_methods->at(i);
4327 method->set_constants(scratch_class->constants());
4328 }
4329 }
4330 } while (ik != nullptr);
4331 }
4332 #endif
4333
4334 // Replace methods and constantpool
4335 the_class->set_methods(_new_methods);
4336 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods,
4337 // and to be able to undo operation easily.
4338
4339 Array<int>* old_ordering = the_class->method_ordering();
4340 the_class->set_method_ordering(scratch_class->method_ordering());
4341 scratch_class->set_method_ordering(old_ordering);
4342
4343 ConstantPool* old_constants = the_class->constants();
4344 the_class->set_constants(scratch_class->constants());
4345 scratch_class->set_constants(old_constants); // See the previous comment.
4346 #if 0
4347 // We are swapping the guts of "the new class" with the guts of "the
4348 // class". Since the old constant pool has just been attached to "the
4349 // new class", it seems logical to set the pool holder in the old
4350 // constant pool also. However, doing this will change the observable
4351 // class hierarchy for any old methods that are still executing. A
4352 // method can query the identity of its "holder" and this query uses
4353 // the method's constant pool link to find the holder. The change in
4354 // holding class from "the class" to "the new class" can confuse
4355 // things.
4356 //
4357 // Setting the old constant pool's holder will also cause
4358 // verification done during vtable initialization below to fail.
4359 // During vtable initialization, the vtable's class is verified to be
4360 // a subtype of the method's holder. The vtable's class is "the
4361 // class" and the method's holder is gotten from the constant pool
4362 // link in the method itself. For "the class"'s directly implemented
4363 // methods, the method holder is "the class" itself (as gotten from
4364 // the new constant pool). The check works fine in this case. The
4365 // check also works fine for methods inherited from super classes.
4366 //
4367 // Miranda methods are a little more complicated. A miranda method is
4368 // provided by an interface when the class implementing the interface
4369 // does not provide its own method. These interfaces are implemented
4370 // internally as an InstanceKlass. These special instanceKlasses
4371 // share the constant pool of the class that "implements" the
4372 // interface. By sharing the constant pool, the method holder of a
4373 // miranda method is the class that "implements" the interface. In a
4374 // non-redefine situation, the subtype check works fine. However, if
4375 // the old constant pool's pool holder is modified, then the check
4376 // fails because there is no class hierarchy relationship between the
4377 // vtable's class and "the new class".
4378
4379 old_constants->set_pool_holder(scratch_class());
4380 #endif
4381
4382 // track number of methods that are EMCP for add_previous_version() call below
4383 int emcp_method_count = check_methods_and_mark_as_obsolete();
4384 transfer_old_native_function_registrations(the_class);
4385
4386 if (scratch_class->get_cached_class_file() != the_class->get_cached_class_file()) {
4387 // 1. the_class doesn't have a cache yet, scratch_class does have a cache.
4388 // 2. The same class can be present twice in the scratch classes list or there
4389 // are multiple concurrent RetransformClasses calls on different threads.
4390 // the_class and scratch_class have the same cached bytes, but different buffers.
4391 // In such cases we need to deallocate one of the buffers.
4392 // 3. RedefineClasses and the_class has cached bytes from a previous transformation.
4393 // In the case we need to use class bytes from scratch_class.
4394 if (the_class->get_cached_class_file() != nullptr) {
4395 os::free(the_class->get_cached_class_file());
4396 }
4397 the_class->set_cached_class_file(scratch_class->get_cached_class_file());
4398 }
4399
4400 // null out in scratch class to not delete twice. The class to be redefined
4401 // always owns these bytes.
4402 scratch_class->set_cached_class_file(nullptr);
4403
4404 // Replace inner_classes
4405 Array<u2>* old_inner_classes = the_class->inner_classes();
4406 the_class->set_inner_classes(scratch_class->inner_classes());
4407 scratch_class->set_inner_classes(old_inner_classes);
4408
4409 // Initialize the vtable and interface table after
4410 // methods have been rewritten
4411 // no exception should happen here since we explicitly
4412 // do not check loader constraints.
4413 // compare_and_normalize_class_versions has already checked:
4414 // - classloaders unchanged, signatures unchanged
4415 // - all instanceKlasses for redefined classes reused & contents updated
4416 the_class->vtable().initialize_vtable();
4417 the_class->itable().initialize_itable();
4418
4419 // Leave arrays of jmethodIDs and itable index cache unchanged
4420
4421 // Copy the "source debug extension" attribute from new class version
4422 the_class->set_source_debug_extension(
4423 scratch_class->source_debug_extension(),
4424 scratch_class->source_debug_extension() == nullptr ? 0 :
4425 (int)strlen(scratch_class->source_debug_extension()));
4426
4427 // Use of javac -g could be different in the old and the new
4428 if (scratch_class->has_localvariable_table() !=
4429 the_class->has_localvariable_table()) {
4430 the_class->set_has_localvariable_table(scratch_class->has_localvariable_table());
4431 }
4432
4433 swap_annotations(the_class, scratch_class);
4434
4435 // Replace minor version number of class file
4436 u2 old_minor_version = the_class->constants()->minor_version();
4437 the_class->constants()->set_minor_version(scratch_class->constants()->minor_version());
4438 scratch_class->constants()->set_minor_version(old_minor_version);
4439
4440 // Replace major version number of class file
4441 u2 old_major_version = the_class->constants()->major_version();
4442 the_class->constants()->set_major_version(scratch_class->constants()->major_version());
4443 scratch_class->constants()->set_major_version(old_major_version);
4444
4445 // Replace CP indexes for class and name+type of enclosing method
4446 u2 old_class_idx = the_class->enclosing_method_class_index();
4447 u2 old_method_idx = the_class->enclosing_method_method_index();
4448 the_class->set_enclosing_method_indices(
4449 scratch_class->enclosing_method_class_index(),
4450 scratch_class->enclosing_method_method_index());
4451 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx);
4452
4453 if (!the_class->has_been_redefined()) {
4454 the_class->set_has_been_redefined();
4455 }
4456
4457 // Scratch class is unloaded but still needs cleaning, and skipping for CDS.
4458 scratch_class->set_is_scratch_class();
4459
4460 // keep track of previous versions of this class
4461 the_class->add_previous_version(scratch_class, emcp_method_count);
4462
4463 _timer_rsc_phase1.stop();
4464 if (log_is_enabled(Info, redefine, class, timer)) {
4465 _timer_rsc_phase2.start();
4466 }
4467
4468 if (the_class->oop_map_cache() != nullptr) {
4469 // Flush references to any obsolete methods from the oop map cache
4470 // so that obsolete methods are not pinned.
4471 the_class->oop_map_cache()->flush_obsolete_entries();
4472 }
4473
4474 increment_class_counter(the_class);
4475
4476 if (EventClassRedefinition::is_enabled()) {
4477 EventClassRedefinition event;
4478 event.set_classModificationCount(java_lang_Class::classRedefinedCount(the_class->java_mirror()));
4479 event.set_redefinedClass(the_class);
4480 event.set_redefinitionId(_id);
4481 event.commit();
4482 }
4483
4484 {
4485 ResourceMark rm(current);
4486 // increment the classRedefinedCount field in the_class and in any
4487 // direct and indirect subclasses of the_class
4488 log_info(redefine, class, load)
4489 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)",
4490 the_class->external_name(), java_lang_Class::classRedefinedCount(the_class->java_mirror()), os::available_memory() >> 10);
4491 Events::log_redefinition(current, "redefined class name=%s, count=%d",
4492 the_class->external_name(),
4493 java_lang_Class::classRedefinedCount(the_class->java_mirror()));
4494
4495 }
4496 _timer_rsc_phase2.stop();
4497
4498 } // end redefine_single_class()
4499
4500
4501 // Increment the classRedefinedCount field in the specific InstanceKlass
4502 // and in all direct and indirect subclasses.
4503 void VM_RedefineClasses::increment_class_counter(InstanceKlass* ik) {
4504 for (ClassHierarchyIterator iter(ik); !iter.done(); iter.next()) {
4505 // Only update instanceKlasses
4506 Klass* sub = iter.klass();
4507 if (sub->is_instance_klass()) {
4508 oop class_mirror = InstanceKlass::cast(sub)->java_mirror();
4509 Klass* class_oop = java_lang_Class::as_Klass(class_mirror);
4510 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
4511 java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
4512
4513 if (class_oop != _the_class) {
4514 // _the_class count is printed at end of redefine_single_class()
4515 log_debug(redefine, class, subclass)("updated count in subclass=%s to %d", ik->external_name(), new_count);
4516 }
4517 }
4518 }
4519 }
4520
4521 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) {
4522 bool no_old_methods = true; // be optimistic
4523
4524 // Both array and instance classes have vtables.
4525 // a vtable should never contain old or obsolete methods
4526 ResourceMark rm(_thread);
4527 if (k->vtable_length() > 0 &&
4528 !k->vtable().check_no_old_or_obsolete_entries()) {
4529 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4530 log_trace(redefine, class, obsolete, metadata)
4531 ("klassVtable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4532 k->signature_name());
4533 k->vtable().dump_vtable();
4534 }
4535 no_old_methods = false;
4536 }
4537
4538 if (k->is_instance_klass()) {
4539 HandleMark hm(_thread);
4540 InstanceKlass *ik = InstanceKlass::cast(k);
4541
4542 // an itable should never contain old or obsolete methods
4543 if (ik->itable_length() > 0 &&
4544 !ik->itable().check_no_old_or_obsolete_entries()) {
4545 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4546 log_trace(redefine, class, obsolete, metadata)
4547 ("klassItable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4548 ik->signature_name());
4549 ik->itable().dump_itable();
4550 }
4551 no_old_methods = false;
4552 }
4553
4554 // the constant pool cache should never contain non-deleted old or obsolete methods
4555 if (ik->constants() != nullptr &&
4556 ik->constants()->cache() != nullptr &&
4557 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) {
4558 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4559 log_trace(redefine, class, obsolete, metadata)
4560 ("cp-cache::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4561 ik->signature_name());
4562 ik->constants()->cache()->dump_cache();
4563 }
4564 no_old_methods = false;
4565 }
4566 }
4567
4568 // print and fail guarantee if old methods are found.
4569 if (!no_old_methods) {
4570 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4571 dump_methods();
4572 } else {
4573 log_trace(redefine, class)("Use the '-Xlog:redefine+class*:' option "
4574 "to see more info about the following guarantee() failure.");
4575 }
4576 guarantee(false, "OLD and/or OBSOLETE method(s) found");
4577 }
4578 }
4579
4580 u8 VM_RedefineClasses::next_id() {
4581 while (true) {
4582 u8 id = _id_counter;
4583 u8 next_id = id + 1;
4584 u8 result = Atomic::cmpxchg(&_id_counter, id, next_id);
4585 if (result == id) {
4586 return next_id;
4587 }
4588 }
4589 }
4590
4591 void VM_RedefineClasses::dump_methods() {
4592 int j;
4593 log_trace(redefine, class, dump)("_old_methods --");
4594 for (j = 0; j < _old_methods->length(); ++j) {
4595 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4596 Method* m = _old_methods->at(j);
4597 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4598 m->access_flags().print_on(&log_stream);
4599 log_stream.print(" -- ");
4600 m->print_name(&log_stream);
4601 log_stream.cr();
4602 }
4603 log_trace(redefine, class, dump)("_new_methods --");
4604 for (j = 0; j < _new_methods->length(); ++j) {
4605 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4606 Method* m = _new_methods->at(j);
4607 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4608 m->access_flags().print_on(&log_stream);
4609 log_stream.print(" -- ");
4610 m->print_name(&log_stream);
4611 log_stream.cr();
4612 }
4613 log_trace(redefine, class, dump)("_matching_methods --");
4614 for (j = 0; j < _matching_methods_length; ++j) {
4615 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4616 Method* m = _matching_old_methods[j];
4617 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4618 m->access_flags().print_on(&log_stream);
4619 log_stream.print(" -- ");
4620 m->print_name();
4621 log_stream.cr();
4622
4623 m = _matching_new_methods[j];
4624 log_stream.print(" (%5d) ", m->vtable_index());
4625 m->access_flags().print_on(&log_stream);
4626 log_stream.cr();
4627 }
4628 log_trace(redefine, class, dump)("_deleted_methods --");
4629 for (j = 0; j < _deleted_methods_length; ++j) {
4630 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4631 Method* m = _deleted_methods[j];
4632 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4633 m->access_flags().print_on(&log_stream);
4634 log_stream.print(" -- ");
4635 m->print_name(&log_stream);
4636 log_stream.cr();
4637 }
4638 log_trace(redefine, class, dump)("_added_methods --");
4639 for (j = 0; j < _added_methods_length; ++j) {
4640 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4641 Method* m = _added_methods[j];
4642 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4643 m->access_flags().print_on(&log_stream);
4644 log_stream.print(" -- ");
4645 m->print_name(&log_stream);
4646 log_stream.cr();
4647 }
4648 }
4649
4650 void VM_RedefineClasses::print_on_error(outputStream* st) const {
4651 VM_Operation::print_on_error(st);
4652 if (_the_class != nullptr) {
4653 ResourceMark rm;
4654 st->print_cr(", redefining class %s", _the_class->external_name());
4655 }
4656 }