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/checkedCast.hpp"
66 #include "utilities/events.hpp"
67
68 Array<Method*>* VM_RedefineClasses::_old_methods = nullptr;
69 Array<Method*>* VM_RedefineClasses::_new_methods = nullptr;
70 Method** VM_RedefineClasses::_matching_old_methods = nullptr;
71 Method** VM_RedefineClasses::_matching_new_methods = nullptr;
72 Method** VM_RedefineClasses::_deleted_methods = nullptr;
73 Method** VM_RedefineClasses::_added_methods = nullptr;
74 int VM_RedefineClasses::_matching_methods_length = 0;
75 int VM_RedefineClasses::_deleted_methods_length = 0;
76 int VM_RedefineClasses::_added_methods_length = 0;
77
78 // This flag is global as the constructor does not reset it:
79 bool VM_RedefineClasses::_has_redefined_Object = false;
80 u8 VM_RedefineClasses::_id_counter = 0;
81
82 VM_RedefineClasses::VM_RedefineClasses(jint class_count,
83 const jvmtiClassDefinition *class_defs,
84 JvmtiClassLoadKind class_load_kind) {
85 _class_count = class_count;
86 _class_defs = class_defs;
87 _class_load_kind = class_load_kind;
88 _any_class_has_resolved_methods = false;
89 _res = JVMTI_ERROR_NONE;
90 _the_class = nullptr;
91 _id = next_id();
92 }
93
94 static inline InstanceKlass* get_ik(jclass def) {
95 oop mirror = JNIHandles::resolve_non_null(def);
96 return InstanceKlass::cast(java_lang_Class::as_Klass(mirror));
97 }
98
99 // If any of the classes are being redefined, wait
100 // Parallel constant pool merging leads to indeterminate constant pools.
101 void VM_RedefineClasses::lock_classes() {
102 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
103 GrowableArray<Klass*>* redef_classes = state->get_classes_being_redefined();
104
105 MonitorLocker ml(RedefineClasses_lock);
106
107 if (redef_classes == nullptr) {
108 redef_classes = new (mtClass) GrowableArray<Klass*>(1, mtClass);
109 state->set_classes_being_redefined(redef_classes);
110 }
111
112 bool has_redefined;
113 do {
114 has_redefined = false;
115 // Go through classes each time until none are being redefined. Skip
116 // the ones that are being redefined by this thread currently. Class file
117 // load hook event may trigger new class redefine when we are redefining
118 // a class (after lock_classes()).
119 for (int i = 0; i < _class_count; i++) {
120 InstanceKlass* ik = get_ik(_class_defs[i].klass);
121 // Check if we are currently redefining the class in this thread already.
122 if (redef_classes->contains(ik)) {
123 assert(ik->is_being_redefined(), "sanity");
124 } else {
125 if (ik->is_being_redefined()) {
126 ml.wait();
127 has_redefined = true;
128 break; // for loop
129 }
130 }
131 }
132 } while (has_redefined);
133
134 for (int i = 0; i < _class_count; i++) {
135 InstanceKlass* ik = get_ik(_class_defs[i].klass);
136 redef_classes->push(ik); // Add to the _classes_being_redefined list
137 ik->set_is_being_redefined(true);
138 }
139 ml.notify_all();
140 }
141
142 void VM_RedefineClasses::unlock_classes() {
143 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
144 GrowableArray<Klass*>* redef_classes = state->get_classes_being_redefined();
145 assert(redef_classes != nullptr, "_classes_being_redefined is not allocated");
146
147 MonitorLocker ml(RedefineClasses_lock);
148
149 for (int i = _class_count - 1; i >= 0; i--) {
150 InstanceKlass* def_ik = get_ik(_class_defs[i].klass);
151 if (redef_classes->length() > 0) {
152 // Remove the class from _classes_being_redefined list
153 Klass* k = redef_classes->pop();
154 assert(def_ik == k, "unlocking wrong class");
155 }
156 assert(def_ik->is_being_redefined(),
157 "should be being redefined to get here");
158
159 // Unlock after we finish all redefines for this class within
160 // the thread. Same class can be pushed to the list multiple
161 // times (not more than once by each recursive redefinition).
162 if (!redef_classes->contains(def_ik)) {
163 def_ik->set_is_being_redefined(false);
164 }
165 }
166 ml.notify_all();
167 }
168
169 bool VM_RedefineClasses::doit_prologue() {
170 if (_class_count == 0) {
171 _res = JVMTI_ERROR_NONE;
172 return false;
173 }
174 if (_class_defs == nullptr) {
175 _res = JVMTI_ERROR_NULL_POINTER;
176 return false;
177 }
178
179 for (int i = 0; i < _class_count; i++) {
180 if (_class_defs[i].klass == nullptr) {
181 _res = JVMTI_ERROR_INVALID_CLASS;
182 return false;
183 }
184 if (_class_defs[i].class_byte_count == 0) {
185 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT;
186 return false;
187 }
188 if (_class_defs[i].class_bytes == nullptr) {
189 _res = JVMTI_ERROR_NULL_POINTER;
190 return false;
191 }
192
193 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass);
194 // classes for primitives, arrays, and hidden classes
195 // cannot be redefined.
196 if (!is_modifiable_class(mirror)) {
197 _res = JVMTI_ERROR_UNMODIFIABLE_CLASS;
198 return false;
199 }
200 }
201
202 // Start timer after all the sanity checks; not quite accurate, but
203 // better than adding a bunch of stop() calls.
204 if (log_is_enabled(Info, redefine, class, timer)) {
205 _timer_vm_op_prologue.start();
206 }
207
208 lock_classes();
209 // We first load new class versions in the prologue, because somewhere down the
210 // call chain it is required that the current thread is a Java thread.
211 _res = load_new_class_versions();
212 if (_res != JVMTI_ERROR_NONE) {
213 // free any successfully created classes, since none are redefined
214 for (int i = 0; i < _class_count; i++) {
215 if (_scratch_classes[i] != nullptr) {
216 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data();
217 // Free the memory for this class at class unloading time. Not before
218 // because CMS might think this is still live.
219 InstanceKlass* ik = get_ik(_class_defs[i].klass);
220 if (ik->get_cached_class_file() == _scratch_classes[i]->get_cached_class_file()) {
221 // Don't double-free cached_class_file copied from the original class if error.
222 _scratch_classes[i]->set_cached_class_file(nullptr);
223 }
224 cld->add_to_deallocate_list(InstanceKlass::cast(_scratch_classes[i]));
225 }
226 }
227 // Free os::malloc allocated memory in load_new_class_version.
228 os::free(_scratch_classes);
229 _timer_vm_op_prologue.stop();
230 unlock_classes();
231 return false;
232 }
233
234 _timer_vm_op_prologue.stop();
235 return true;
236 }
237
238 void VM_RedefineClasses::doit() {
239 Thread* current = Thread::current();
240
241 if (log_is_enabled(Info, redefine, class, timer)) {
242 _timer_vm_op_doit.start();
243 }
244
245 #if INCLUDE_CDS
246 if (UseSharedSpaces) {
247 // Sharing is enabled so we remap the shared readonly space to
248 // shared readwrite, private just in case we need to redefine
249 // a shared class. We do the remap during the doit() phase of
250 // the safepoint to be safer.
251 if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) {
252 log_info(redefine, class, load)("failed to remap shared readonly space to readwrite, private");
253 _res = JVMTI_ERROR_INTERNAL;
254 _timer_vm_op_doit.stop();
255 return;
256 }
257 }
258 #endif
259
260 // Mark methods seen on stack and everywhere else so old methods are not
261 // cleaned up if they're on the stack.
262 MetadataOnStackMark md_on_stack(/*walk_all_metadata*/true, /*redefinition_walk*/true);
263 HandleMark hm(current); // make sure any handles created are deleted
264 // before the stack walk again.
265
266 for (int i = 0; i < _class_count; i++) {
267 redefine_single_class(current, _class_defs[i].klass, _scratch_classes[i]);
268 }
269
270 // Flush all compiled code that depends on the classes redefined.
271 flush_dependent_code();
272
273 // Adjust constantpool caches and vtables for all classes
274 // that reference methods of the evolved classes.
275 // Have to do this after all classes are redefined and all methods that
276 // are redefined are marked as old.
277 AdjustAndCleanMetadata adjust_and_clean_metadata(current);
278 ClassLoaderDataGraph::classes_do(&adjust_and_clean_metadata);
279
280 // JSR-292 support
281 if (_any_class_has_resolved_methods) {
282 bool trace_name_printed = false;
283 ResolvedMethodTable::adjust_method_entries(&trace_name_printed);
284 }
285
286 // Increment flag indicating that some invariants are no longer true.
287 // See jvmtiExport.hpp for detailed explanation.
288 JvmtiExport::increment_redefinition_count();
289
290 // check_class() is optionally called for product bits, but is
291 // always called for non-product bits.
292 #ifdef PRODUCT
293 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
294 #endif
295 log_trace(redefine, class, obsolete, metadata)("calling check_class");
296 CheckClass check_class(current);
297 ClassLoaderDataGraph::classes_do(&check_class);
298 #ifdef PRODUCT
299 }
300 #endif
301
302 // Clean up any metadata now unreferenced while MetadataOnStackMark is set.
303 ClassLoaderDataGraph::clean_deallocate_lists(false);
304
305 _timer_vm_op_doit.stop();
306 }
307
308 void VM_RedefineClasses::doit_epilogue() {
309 unlock_classes();
310
311 // Free os::malloc allocated memory.
312 os::free(_scratch_classes);
313
314 // Reset the_class to null for error printing.
315 _the_class = nullptr;
316
317 if (log_is_enabled(Info, redefine, class, timer)) {
318 // Used to have separate timers for "doit" and "all", but the timer
319 // overhead skewed the measurements.
320 julong doit_time = _timer_vm_op_doit.milliseconds();
321 julong all_time = _timer_vm_op_prologue.milliseconds() + doit_time;
322
323 log_info(redefine, class, timer)
324 ("vm_op: all=" JULONG_FORMAT " prologue=" JULONG_FORMAT " doit=" JULONG_FORMAT,
325 all_time, (julong)_timer_vm_op_prologue.milliseconds(), doit_time);
326 log_info(redefine, class, timer)
327 ("redefine_single_class: phase1=" JULONG_FORMAT " phase2=" JULONG_FORMAT,
328 (julong)_timer_rsc_phase1.milliseconds(), (julong)_timer_rsc_phase2.milliseconds());
329 }
330 }
331
332 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) {
333 // classes for primitives cannot be redefined
334 if (java_lang_Class::is_primitive(klass_mirror)) {
335 return false;
336 }
337 Klass* k = java_lang_Class::as_Klass(klass_mirror);
338 // classes for arrays cannot be redefined
339 if (k == nullptr || !k->is_instance_klass()) {
340 return false;
341 }
342
343 // Cannot redefine or retransform a hidden class.
344 if (InstanceKlass::cast(k)->is_hidden()) {
345 return false;
346 }
347 if (InstanceKlass::cast(k) == vmClasses::Continuation_klass()) {
348 // Don't redefine Continuation class. See 8302779.
349 return false;
350 }
351 return true;
352 }
353
354 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p
355 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For
356 // direct CP entries, there is just the current entry to append. For
357 // indirect and double-indirect CP entries, there are zero or more
358 // referenced CP entries along with the current entry to append.
359 // Indirect and double-indirect CP entries are handled by recursive
360 // calls to append_entry() as needed. The referenced CP entries are
361 // always appended to *merge_cp_p before the referee CP entry. These
362 // referenced CP entries may already exist in *merge_cp_p in which case
363 // there is nothing extra to append and only the current entry is
364 // appended.
365 void VM_RedefineClasses::append_entry(const constantPoolHandle& scratch_cp,
366 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) {
367
368 // append is different depending on entry tag type
369 switch (scratch_cp->tag_at(scratch_i).value()) {
370
371 // The old verifier is implemented outside the VM. It loads classes,
372 // but does not resolve constant pool entries directly so we never
373 // see Class entries here with the old verifier. Similarly the old
374 // verifier does not like Class entries in the input constant pool.
375 // The split-verifier is implemented in the VM so it can optionally
376 // and directly resolve constant pool entries to load classes. The
377 // split-verifier can accept either Class entries or UnresolvedClass
378 // entries in the input constant pool. We revert the appended copy
379 // back to UnresolvedClass so that either verifier will be happy
380 // with the constant pool entry.
381 //
382 // this is an indirect CP entry so it needs special handling
383 case JVM_CONSTANT_Class:
384 case JVM_CONSTANT_UnresolvedClass:
385 {
386 int name_i = scratch_cp->klass_name_index_at(scratch_i);
387 int new_name_i = find_or_append_indirect_entry(scratch_cp, name_i, merge_cp_p,
388 merge_cp_length_p);
389
390 if (new_name_i != name_i) {
391 log_trace(redefine, class, constantpool)
392 ("Class entry@%d name_index change: %d to %d",
393 *merge_cp_length_p, name_i, new_name_i);
394 }
395
396 (*merge_cp_p)->temp_unresolved_klass_at_put(*merge_cp_length_p, new_name_i);
397 if (scratch_i != *merge_cp_length_p) {
398 // The new entry in *merge_cp_p is at a different index than
399 // the new entry in scratch_cp so we need to map the index values.
400 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
401 }
402 (*merge_cp_length_p)++;
403 } break;
404
405 // these are direct CP entries so they can be directly appended,
406 // but double and long take two constant pool entries
407 case JVM_CONSTANT_Double: // fall through
408 case JVM_CONSTANT_Long:
409 {
410 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p);
411
412 if (scratch_i != *merge_cp_length_p) {
413 // The new entry in *merge_cp_p is at a different index than
414 // the new entry in scratch_cp so we need to map the index values.
415 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
416 }
417 (*merge_cp_length_p) += 2;
418 } break;
419
420 // these are direct CP entries so they can be directly appended
421 case JVM_CONSTANT_Float: // fall through
422 case JVM_CONSTANT_Integer: // fall through
423 case JVM_CONSTANT_Utf8: // fall through
424
425 // This was an indirect CP entry, but it has been changed into
426 // Symbol*s so this entry can be directly appended.
427 case JVM_CONSTANT_String: // fall through
428 {
429 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p);
430
431 if (scratch_i != *merge_cp_length_p) {
432 // The new entry in *merge_cp_p is at a different index than
433 // the new entry in scratch_cp so we need to map the index values.
434 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
435 }
436 (*merge_cp_length_p)++;
437 } break;
438
439 // this is an indirect CP entry so it needs special handling
440 case JVM_CONSTANT_NameAndType:
441 {
442 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i);
443 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p,
444 merge_cp_length_p);
445
446 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i);
447 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i,
448 merge_cp_p, merge_cp_length_p);
449
450 // If the referenced entries already exist in *merge_cp_p, then
451 // both new_name_ref_i and new_signature_ref_i will both be 0.
452 // In that case, all we are appending is the current entry.
453 if (new_name_ref_i != name_ref_i) {
454 log_trace(redefine, class, constantpool)
455 ("NameAndType entry@%d name_ref_index change: %d to %d",
456 *merge_cp_length_p, name_ref_i, new_name_ref_i);
457 }
458 if (new_signature_ref_i != signature_ref_i) {
459 log_trace(redefine, class, constantpool)
460 ("NameAndType entry@%d signature_ref_index change: %d to %d",
461 *merge_cp_length_p, signature_ref_i, new_signature_ref_i);
462 }
463
464 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p,
465 new_name_ref_i, new_signature_ref_i);
466 if (scratch_i != *merge_cp_length_p) {
467 // The new entry in *merge_cp_p is at a different index than
468 // the new entry in scratch_cp so we need to map the index values.
469 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
470 }
471 (*merge_cp_length_p)++;
472 } break;
473
474 // this is a double-indirect CP entry so it needs special handling
475 case JVM_CONSTANT_Fieldref: // fall through
476 case JVM_CONSTANT_InterfaceMethodref: // fall through
477 case JVM_CONSTANT_Methodref:
478 {
479 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i);
480 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i,
481 merge_cp_p, merge_cp_length_p);
482
483 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i);
484 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i,
485 merge_cp_p, merge_cp_length_p);
486
487 const char *entry_name = nullptr;
488 switch (scratch_cp->tag_at(scratch_i).value()) {
489 case JVM_CONSTANT_Fieldref:
490 entry_name = "Fieldref";
491 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i,
492 new_name_and_type_ref_i);
493 break;
494 case JVM_CONSTANT_InterfaceMethodref:
495 entry_name = "IFMethodref";
496 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p,
497 new_klass_ref_i, new_name_and_type_ref_i);
498 break;
499 case JVM_CONSTANT_Methodref:
500 entry_name = "Methodref";
501 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i,
502 new_name_and_type_ref_i);
503 break;
504 default:
505 guarantee(false, "bad switch");
506 break;
507 }
508
509 if (klass_ref_i != new_klass_ref_i) {
510 log_trace(redefine, class, constantpool)
511 ("%s entry@%d class_index changed: %d to %d", entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i);
512 }
513 if (name_and_type_ref_i != new_name_and_type_ref_i) {
514 log_trace(redefine, class, constantpool)
515 ("%s entry@%d name_and_type_index changed: %d to %d",
516 entry_name, *merge_cp_length_p, name_and_type_ref_i, new_name_and_type_ref_i);
517 }
518
519 if (scratch_i != *merge_cp_length_p) {
520 // The new entry in *merge_cp_p is at a different index than
521 // the new entry in scratch_cp so we need to map the index values.
522 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
523 }
524 (*merge_cp_length_p)++;
525 } break;
526
527 // this is an indirect CP entry so it needs special handling
528 case JVM_CONSTANT_MethodType:
529 {
530 int ref_i = scratch_cp->method_type_index_at(scratch_i);
531 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
532 merge_cp_length_p);
533 if (new_ref_i != ref_i) {
534 log_trace(redefine, class, constantpool)
535 ("MethodType entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i);
536 }
537 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i);
538 if (scratch_i != *merge_cp_length_p) {
539 // The new entry in *merge_cp_p is at a different index than
540 // the new entry in scratch_cp so we need to map the index values.
541 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
542 }
543 (*merge_cp_length_p)++;
544 } break;
545
546 // this is an indirect CP entry so it needs special handling
547 case JVM_CONSTANT_MethodHandle:
548 {
549 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i);
550 int ref_i = scratch_cp->method_handle_index_at(scratch_i);
551 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
552 merge_cp_length_p);
553 if (new_ref_i != ref_i) {
554 log_trace(redefine, class, constantpool)
555 ("MethodHandle entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i);
556 }
557 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i);
558 if (scratch_i != *merge_cp_length_p) {
559 // The new entry in *merge_cp_p is at a different index than
560 // the new entry in scratch_cp so we need to map the index values.
561 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
562 }
563 (*merge_cp_length_p)++;
564 } break;
565
566 // this is an indirect CP entry so it needs special handling
567 case JVM_CONSTANT_Dynamic: // fall through
568 case JVM_CONSTANT_InvokeDynamic:
569 {
570 // Index of the bootstrap specifier in the operands array
571 int old_bs_i = scratch_cp->bootstrap_methods_attribute_index(scratch_i);
572 int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p,
573 merge_cp_length_p);
574 // The bootstrap method NameAndType_info index
575 int old_ref_i = scratch_cp->bootstrap_name_and_type_ref_index_at(scratch_i);
576 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
577 merge_cp_length_p);
578 if (new_bs_i != old_bs_i) {
579 log_trace(redefine, class, constantpool)
580 ("Dynamic entry@%d bootstrap_method_attr_index change: %d to %d",
581 *merge_cp_length_p, old_bs_i, new_bs_i);
582 }
583 if (new_ref_i != old_ref_i) {
584 log_trace(redefine, class, constantpool)
585 ("Dynamic entry@%d name_and_type_index change: %d to %d", *merge_cp_length_p, old_ref_i, new_ref_i);
586 }
587
588 if (scratch_cp->tag_at(scratch_i).is_dynamic_constant())
589 (*merge_cp_p)->dynamic_constant_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
590 else
591 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
592 if (scratch_i != *merge_cp_length_p) {
593 // The new entry in *merge_cp_p is at a different index than
594 // the new entry in scratch_cp so we need to map the index values.
595 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
596 }
597 (*merge_cp_length_p)++;
598 } break;
599
600 // At this stage, Class or UnresolvedClass could be in scratch_cp, but not
601 // ClassIndex
602 case JVM_CONSTANT_ClassIndex: // fall through
603
604 // Invalid is used as the tag for the second constant pool entry
605 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
606 // not be seen by itself.
607 case JVM_CONSTANT_Invalid: // fall through
608
609 // At this stage, String could be here, but not StringIndex
610 case JVM_CONSTANT_StringIndex: // fall through
611
612 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be here
613 case JVM_CONSTANT_UnresolvedClassInError: // fall through
614
615 default:
616 {
617 // leave a breadcrumb
618 jbyte bad_value = scratch_cp->tag_at(scratch_i).value();
619 ShouldNotReachHere();
620 } break;
621 } // end switch tag value
622 } // end append_entry()
623
624
625 u2 VM_RedefineClasses::find_or_append_indirect_entry(const constantPoolHandle& scratch_cp,
626 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) {
627
628 int new_ref_i = ref_i;
629 bool match = (ref_i < *merge_cp_length_p) &&
630 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i);
631
632 if (!match) {
633 // forward reference in *merge_cp_p or not a direct match
634 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p);
635 if (found_i != 0) {
636 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree");
637 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry.
638 new_ref_i = found_i;
639 map_index(scratch_cp, ref_i, found_i);
640 } else {
641 // no match found so we have to append this entry to *merge_cp_p
642 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p);
643 // The above call to append_entry() can only append one entry
644 // so the post call query of *merge_cp_length_p is only for
645 // the sake of consistency.
646 new_ref_i = *merge_cp_length_p - 1;
647 }
648 }
649
650 // constant pool indices are u2, unless the merged constant pool overflows which
651 // we don't check for.
652 return checked_cast<u2>(new_ref_i);
653 } // end find_or_append_indirect_entry()
654
655
656 // Append a bootstrap specifier into the merge_cp operands that is semantically equal
657 // to the scratch_cp operands bootstrap specifier passed by the old_bs_i index.
658 // Recursively append new merge_cp entries referenced by the new bootstrap specifier.
659 void VM_RedefineClasses::append_operand(const constantPoolHandle& scratch_cp, int old_bs_i,
660 constantPoolHandle *merge_cp_p, int *merge_cp_length_p) {
661
662 u2 old_ref_i = scratch_cp->operand_bootstrap_method_ref_index_at(old_bs_i);
663 u2 new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
664 merge_cp_length_p);
665 if (new_ref_i != old_ref_i) {
666 log_trace(redefine, class, constantpool)
667 ("operands entry@%d bootstrap method ref_index change: %d to %d", _operands_cur_length, old_ref_i, new_ref_i);
668 }
669
670 Array<u2>* merge_ops = (*merge_cp_p)->operands();
671 int new_bs_i = _operands_cur_length;
672 // We have _operands_cur_length == 0 when the merge_cp operands is empty yet.
673 // However, the operand_offset_at(0) was set in the extend_operands() call.
674 int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0)
675 : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1);
676 u2 argc = scratch_cp->operand_argument_count_at(old_bs_i);
677
678 ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base);
679 merge_ops->at_put(new_base++, new_ref_i);
680 merge_ops->at_put(new_base++, argc);
681
682 for (int i = 0; i < argc; i++) {
683 u2 old_arg_ref_i = scratch_cp->operand_argument_index_at(old_bs_i, i);
684 u2 new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p,
685 merge_cp_length_p);
686 merge_ops->at_put(new_base++, new_arg_ref_i);
687 if (new_arg_ref_i != old_arg_ref_i) {
688 log_trace(redefine, class, constantpool)
689 ("operands entry@%d bootstrap method argument ref_index change: %d to %d",
690 _operands_cur_length, old_arg_ref_i, new_arg_ref_i);
691 }
692 }
693 if (old_bs_i != _operands_cur_length) {
694 // The bootstrap specifier in *merge_cp_p is at a different index than
695 // that in scratch_cp so we need to map the index values.
696 map_operand_index(old_bs_i, new_bs_i);
697 }
698 _operands_cur_length++;
699 } // end append_operand()
700
701
702 int VM_RedefineClasses::find_or_append_operand(const constantPoolHandle& scratch_cp,
703 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) {
704
705 int new_bs_i = old_bs_i; // bootstrap specifier index
706 bool match = (old_bs_i < _operands_cur_length) &&
707 scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i);
708
709 if (!match) {
710 // forward reference in *merge_cp_p or not a direct match
711 int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p,
712 _operands_cur_length);
713 if (found_i != -1) {
714 guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree");
715 // found a matching operand somewhere else in *merge_cp_p so just need a mapping
716 new_bs_i = found_i;
717 map_operand_index(old_bs_i, found_i);
718 } else {
719 // no match found so we have to append this bootstrap specifier to *merge_cp_p
720 append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p);
721 new_bs_i = _operands_cur_length - 1;
722 }
723 }
724 return new_bs_i;
725 } // end find_or_append_operand()
726
727
728 void VM_RedefineClasses::finalize_operands_merge(const constantPoolHandle& merge_cp, TRAPS) {
729 if (merge_cp->operands() == nullptr) {
730 return;
731 }
732 // Shrink the merge_cp operands
733 merge_cp->shrink_operands(_operands_cur_length, CHECK);
734
735 if (log_is_enabled(Trace, redefine, class, constantpool)) {
736 // don't want to loop unless we are tracing
737 int count = 0;
738 for (int i = 1; i < _operands_index_map_p->length(); i++) {
739 int value = _operands_index_map_p->at(i);
740 if (value != -1) {
741 log_trace(redefine, class, constantpool)("operands_index_map[%d]: old=%d new=%d", count, i, value);
742 count++;
743 }
744 }
745 }
746 // Clean-up
747 _operands_index_map_p = nullptr;
748 _operands_cur_length = 0;
749 _operands_index_map_count = 0;
750 } // end finalize_operands_merge()
751
752 // Symbol* comparator for qsort
753 // The caller must have an active ResourceMark.
754 static int symcmp(const void* a, const void* b) {
755 char* astr = (*(Symbol**)a)->as_C_string();
756 char* bstr = (*(Symbol**)b)->as_C_string();
757 return strcmp(astr, bstr);
758 }
759
760 // The caller must have an active ResourceMark.
761 static jvmtiError check_attribute_arrays(const char* attr_name,
762 InstanceKlass* the_class, InstanceKlass* scratch_class,
763 Array<u2>* the_array, Array<u2>* scr_array) {
764 bool the_array_exists = the_array != Universe::the_empty_short_array();
765 bool scr_array_exists = scr_array != Universe::the_empty_short_array();
766
767 int array_len = the_array->length();
768 if (the_array_exists && scr_array_exists) {
769 if (array_len != scr_array->length()) {
770 log_trace(redefine, class)
771 ("redefined class %s attribute change error: %s len=%d changed to len=%d",
772 the_class->external_name(), attr_name, array_len, scr_array->length());
773 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
774 }
775
776 // The order of entries in the attribute array is not specified so we
777 // have to explicitly check for the same contents. We do this by copying
778 // the referenced symbols into their own arrays, sorting them and then
779 // comparing each element pair.
780
781 Symbol** the_syms = NEW_RESOURCE_ARRAY_RETURN_NULL(Symbol*, array_len);
782 Symbol** scr_syms = NEW_RESOURCE_ARRAY_RETURN_NULL(Symbol*, array_len);
783
784 if (the_syms == nullptr || scr_syms == nullptr) {
785 return JVMTI_ERROR_OUT_OF_MEMORY;
786 }
787
788 for (int i = 0; i < array_len; i++) {
789 int the_cp_index = the_array->at(i);
790 int scr_cp_index = scr_array->at(i);
791 the_syms[i] = the_class->constants()->klass_name_at(the_cp_index);
792 scr_syms[i] = scratch_class->constants()->klass_name_at(scr_cp_index);
793 }
794
795 qsort(the_syms, array_len, sizeof(Symbol*), symcmp);
796 qsort(scr_syms, array_len, sizeof(Symbol*), symcmp);
797
798 for (int i = 0; i < array_len; i++) {
799 if (the_syms[i] != scr_syms[i]) {
800 log_info(redefine, class)
801 ("redefined class %s attribute change error: %s[%d]: %s changed to %s",
802 the_class->external_name(), attr_name, i,
803 the_syms[i]->as_C_string(), scr_syms[i]->as_C_string());
804 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
805 }
806 }
807 } else if (the_array_exists ^ scr_array_exists) {
808 const char* action_str = (the_array_exists) ? "removed" : "added";
809 log_info(redefine, class)
810 ("redefined class %s attribute change error: %s attribute %s",
811 the_class->external_name(), attr_name, action_str);
812 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
813 }
814 return JVMTI_ERROR_NONE;
815 }
816
817 static jvmtiError check_nest_attributes(InstanceKlass* the_class,
818 InstanceKlass* scratch_class) {
819 // Check whether the class NestHost attribute has been changed.
820 Thread* thread = Thread::current();
821 ResourceMark rm(thread);
822 u2 the_nest_host_idx = the_class->nest_host_index();
823 u2 scr_nest_host_idx = scratch_class->nest_host_index();
824
825 if (the_nest_host_idx != 0 && scr_nest_host_idx != 0) {
826 Symbol* the_sym = the_class->constants()->klass_name_at(the_nest_host_idx);
827 Symbol* scr_sym = scratch_class->constants()->klass_name_at(scr_nest_host_idx);
828 if (the_sym != scr_sym) {
829 log_info(redefine, class, nestmates)
830 ("redefined class %s attribute change error: NestHost class: %s replaced with: %s",
831 the_class->external_name(), the_sym->as_C_string(), scr_sym->as_C_string());
832 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
833 }
834 } else if ((the_nest_host_idx == 0) ^ (scr_nest_host_idx == 0)) {
835 const char* action_str = (the_nest_host_idx != 0) ? "removed" : "added";
836 log_info(redefine, class, nestmates)
837 ("redefined class %s attribute change error: NestHost attribute %s",
838 the_class->external_name(), action_str);
839 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
840 }
841
842 // Check whether the class NestMembers attribute has been changed.
843 return check_attribute_arrays("NestMembers",
844 the_class, scratch_class,
845 the_class->nest_members(),
846 scratch_class->nest_members());
847 }
848
849 // Return an error status if the class Record attribute was changed.
850 static jvmtiError check_record_attribute(InstanceKlass* the_class, InstanceKlass* scratch_class) {
851 // Get lists of record components.
852 Array<RecordComponent*>* the_record = the_class->record_components();
853 Array<RecordComponent*>* scr_record = scratch_class->record_components();
854 bool the_record_exists = the_record != nullptr;
855 bool scr_record_exists = scr_record != nullptr;
856
857 if (the_record_exists && scr_record_exists) {
858 int the_num_components = the_record->length();
859 int scr_num_components = scr_record->length();
860 if (the_num_components != scr_num_components) {
861 log_info(redefine, class, record)
862 ("redefined class %s attribute change error: Record num_components=%d changed to num_components=%d",
863 the_class->external_name(), the_num_components, scr_num_components);
864 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
865 }
866
867 // Compare each field in each record component.
868 ConstantPool* the_cp = the_class->constants();
869 ConstantPool* scr_cp = scratch_class->constants();
870 for (int x = 0; x < the_num_components; x++) {
871 RecordComponent* the_component = the_record->at(x);
872 RecordComponent* scr_component = scr_record->at(x);
873 const Symbol* const the_name = the_cp->symbol_at(the_component->name_index());
874 const Symbol* const scr_name = scr_cp->symbol_at(scr_component->name_index());
875 const Symbol* const the_descr = the_cp->symbol_at(the_component->descriptor_index());
876 const Symbol* const scr_descr = scr_cp->symbol_at(scr_component->descriptor_index());
877 if (the_name != scr_name || the_descr != scr_descr) {
878 log_info(redefine, class, record)
879 ("redefined class %s attribute change error: Record name_index, descriptor_index, and/or attributes_count changed",
880 the_class->external_name());
881 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
882 }
883
884 int the_gen_sig = the_component->generic_signature_index();
885 int scr_gen_sig = scr_component->generic_signature_index();
886 const Symbol* const the_gen_sig_sym = (the_gen_sig == 0 ? nullptr :
887 the_cp->symbol_at(the_component->generic_signature_index()));
888 const Symbol* const scr_gen_sig_sym = (scr_gen_sig == 0 ? nullptr :
889 scr_cp->symbol_at(scr_component->generic_signature_index()));
890 if (the_gen_sig_sym != scr_gen_sig_sym) {
891 log_info(redefine, class, record)
892 ("redefined class %s attribute change error: Record generic_signature attribute changed",
893 the_class->external_name());
894 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
895 }
896
897 // It's okay if a record component's annotations were changed.
898 }
899
900 } else if (the_record_exists ^ scr_record_exists) {
901 const char* action_str = (the_record_exists) ? "removed" : "added";
902 log_info(redefine, class, record)
903 ("redefined class %s attribute change error: Record attribute %s",
904 the_class->external_name(), action_str);
905 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
906 }
907
908 return JVMTI_ERROR_NONE;
909 }
910
911
912 static jvmtiError check_permitted_subclasses_attribute(InstanceKlass* the_class,
913 InstanceKlass* scratch_class) {
914 Thread* thread = Thread::current();
915 ResourceMark rm(thread);
916
917 // Check whether the class PermittedSubclasses attribute has been changed.
918 return check_attribute_arrays("PermittedSubclasses",
919 the_class, scratch_class,
920 the_class->permitted_subclasses(),
921 scratch_class->permitted_subclasses());
922 }
923
924 static jvmtiError check_preload_attribute(InstanceKlass* the_class,
925 InstanceKlass* scratch_class) {
926 Thread* thread = Thread::current();
927 ResourceMark rm(thread);
928
929 // Check whether the class Preload attribute has been changed.
930 return check_attribute_arrays("Preload",
931 the_class, scratch_class,
932 the_class->preload_classes(),
933 scratch_class->preload_classes());
934 }
935
936 static bool can_add_or_delete(Method* m) {
937 // Compatibility mode
938 return (AllowRedefinitionToAddDeleteMethods &&
939 (m->is_private() && (m->is_static() || m->is_final())));
940 }
941
942 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions(
943 InstanceKlass* the_class,
944 InstanceKlass* scratch_class) {
945 int i;
946
947 // Check superclasses, or rather their names, since superclasses themselves can be
948 // requested to replace.
949 // Check for null superclass first since this might be java.lang.Object
950 if (the_class->super() != scratch_class->super() &&
951 (the_class->super() == nullptr || scratch_class->super() == nullptr ||
952 the_class->super()->name() !=
953 scratch_class->super()->name())) {
954 log_info(redefine, class, normalize)
955 ("redefined class %s superclass change error: superclass changed from %s to %s.",
956 the_class->external_name(),
957 the_class->super() == nullptr ? "null" : the_class->super()->external_name(),
958 scratch_class->super() == nullptr ? "null" : scratch_class->super()->external_name());
959 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
960 }
961
962 // Check if the number, names and order of directly implemented interfaces are the same.
963 // I think in principle we should just check if the sets of names of directly implemented
964 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the
965 // .java file, also changes in .class file) should not matter. However, comparing sets is
966 // technically a bit more difficult, and, more importantly, I am not sure at present that the
967 // order of interfaces does not matter on the implementation level, i.e. that the VM does not
968 // rely on it somewhere.
969 Array<InstanceKlass*>* k_interfaces = the_class->local_interfaces();
970 Array<InstanceKlass*>* k_new_interfaces = scratch_class->local_interfaces();
971 int n_intfs = k_interfaces->length();
972 if (n_intfs != k_new_interfaces->length()) {
973 log_info(redefine, class, normalize)
974 ("redefined class %s interfaces change error: number of implemented interfaces changed from %d to %d.",
975 the_class->external_name(), n_intfs, k_new_interfaces->length());
976 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
977 }
978 for (i = 0; i < n_intfs; i++) {
979 if (k_interfaces->at(i)->name() !=
980 k_new_interfaces->at(i)->name()) {
981 log_info(redefine, class, normalize)
982 ("redefined class %s interfaces change error: interface changed from %s to %s.",
983 the_class->external_name(),
984 k_interfaces->at(i)->external_name(), k_new_interfaces->at(i)->external_name());
985 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
986 }
987 }
988
989 // Check whether class is in the error init state.
990 if (the_class->is_in_error_state()) {
991 log_info(redefine, class, normalize)
992 ("redefined class %s is in error init state.", the_class->external_name());
993 // TBD #5057930: special error code is needed in 1.6
994 return JVMTI_ERROR_INVALID_CLASS;
995 }
996
997 // Check whether the nest-related attributes have been changed.
998 jvmtiError err = check_nest_attributes(the_class, scratch_class);
999 if (err != JVMTI_ERROR_NONE) {
1000 return err;
1001 }
1002
1003 // Check whether the Record attribute has been changed.
1004 err = check_record_attribute(the_class, scratch_class);
1005 if (err != JVMTI_ERROR_NONE) {
1006 return err;
1007 }
1008
1009 // Check whether the PermittedSubclasses attribute has been changed.
1010 err = check_permitted_subclasses_attribute(the_class, scratch_class);
1011 if (err != JVMTI_ERROR_NONE) {
1012 return err;
1013 }
1014
1015 // Check whether the Preload attribute has been changed.
1016 err = check_preload_attribute(the_class, scratch_class);
1017 if (err != JVMTI_ERROR_NONE) {
1018 return err;
1019 }
1020
1021 // Check whether class modifiers are the same.
1022 jushort old_flags = (jushort) the_class->access_flags().get_flags();
1023 jushort new_flags = (jushort) scratch_class->access_flags().get_flags();
1024 if (old_flags != new_flags) {
1025 log_info(redefine, class, normalize)
1026 ("redefined class %s modifiers change error: modifiers changed from %d to %d.",
1027 the_class->external_name(), old_flags, new_flags);
1028 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED;
1029 }
1030
1031 // Check if the number, names, types and order of fields declared in these classes
1032 // are the same.
1033 JavaFieldStream old_fs(the_class);
1034 JavaFieldStream new_fs(scratch_class);
1035 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) {
1036 // name and signature
1037 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index());
1038 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index());
1039 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index());
1040 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index());
1041 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) {
1042 log_info(redefine, class, normalize)
1043 ("redefined class %s fields change error: field %s %s changed to %s %s.",
1044 the_class->external_name(),
1045 sig_sym1->as_C_string(), name_sym1->as_C_string(),
1046 sig_sym2->as_C_string(), name_sym2->as_C_string());
1047 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
1048 }
1049 // offset
1050 if (old_fs.offset() != new_fs.offset()) {
1051 log_info(redefine, class, normalize)
1052 ("redefined class %s field %s change error: offset changed from %d to %d.",
1053 the_class->external_name(), name_sym2->as_C_string(), old_fs.offset(), new_fs.offset());
1054 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
1055 }
1056 // access
1057 old_flags = old_fs.access_flags().as_short();
1058 new_flags = new_fs.access_flags().as_short();
1059 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) {
1060 log_info(redefine, class, normalize)
1061 ("redefined class %s field %s change error: modifiers changed from %d to %d.",
1062 the_class->external_name(), name_sym2->as_C_string(), old_flags, new_flags);
1063 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
1064 }
1065 }
1066
1067 // If both streams aren't done then we have a differing number of
1068 // fields.
1069 if (!old_fs.done() || !new_fs.done()) {
1070 const char* action = old_fs.done() ? "added" : "deleted";
1071 log_info(redefine, class, normalize)
1072 ("redefined class %s fields change error: some fields were %s.",
1073 the_class->external_name(), action);
1074 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
1075 }
1076
1077 // Do a parallel walk through the old and new methods. Detect
1078 // cases where they match (exist in both), have been added in
1079 // the new methods, or have been deleted (exist only in the
1080 // old methods). The class file parser places methods in order
1081 // by method name, but does not order overloaded methods by
1082 // signature. In order to determine what fate befell the methods,
1083 // this code places the overloaded new methods that have matching
1084 // old methods in the same order as the old methods and places
1085 // new overloaded methods at the end of overloaded methods of
1086 // that name. The code for this order normalization is adapted
1087 // from the algorithm used in InstanceKlass::find_method().
1088 // Since we are swapping out of order entries as we find them,
1089 // we only have to search forward through the overloaded methods.
1090 // Methods which are added and have the same name as an existing
1091 // method (but different signature) will be put at the end of
1092 // the methods with that name, and the name mismatch code will
1093 // handle them.
1094 Array<Method*>* k_old_methods(the_class->methods());
1095 Array<Method*>* k_new_methods(scratch_class->methods());
1096 int n_old_methods = k_old_methods->length();
1097 int n_new_methods = k_new_methods->length();
1098 Thread* thread = Thread::current();
1099
1100 int ni = 0;
1101 int oi = 0;
1102 while (true) {
1103 Method* k_old_method;
1104 Method* k_new_method;
1105 enum { matched, added, deleted, undetermined } method_was = undetermined;
1106
1107 if (oi >= n_old_methods) {
1108 if (ni >= n_new_methods) {
1109 break; // we've looked at everything, done
1110 }
1111 // New method at the end
1112 k_new_method = k_new_methods->at(ni);
1113 method_was = added;
1114 } else if (ni >= n_new_methods) {
1115 // Old method, at the end, is deleted
1116 k_old_method = k_old_methods->at(oi);
1117 method_was = deleted;
1118 } else {
1119 // There are more methods in both the old and new lists
1120 k_old_method = k_old_methods->at(oi);
1121 k_new_method = k_new_methods->at(ni);
1122 if (k_old_method->name() != k_new_method->name()) {
1123 // Methods are sorted by method name, so a mismatch means added
1124 // or deleted
1125 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) {
1126 method_was = added;
1127 } else {
1128 method_was = deleted;
1129 }
1130 } else if (k_old_method->signature() == k_new_method->signature()) {
1131 // Both the name and signature match
1132 method_was = matched;
1133 } else {
1134 // The name matches, but the signature doesn't, which means we have to
1135 // search forward through the new overloaded methods.
1136 int nj; // outside the loop for post-loop check
1137 for (nj = ni + 1; nj < n_new_methods; nj++) {
1138 Method* m = k_new_methods->at(nj);
1139 if (k_old_method->name() != m->name()) {
1140 // reached another method name so no more overloaded methods
1141 method_was = deleted;
1142 break;
1143 }
1144 if (k_old_method->signature() == m->signature()) {
1145 // found a match so swap the methods
1146 k_new_methods->at_put(ni, m);
1147 k_new_methods->at_put(nj, k_new_method);
1148 k_new_method = m;
1149 method_was = matched;
1150 break;
1151 }
1152 }
1153
1154 if (nj >= n_new_methods) {
1155 // reached the end without a match; so method was deleted
1156 method_was = deleted;
1157 }
1158 }
1159 }
1160
1161 switch (method_was) {
1162 case matched:
1163 // methods match, be sure modifiers do too
1164 old_flags = (jushort) k_old_method->access_flags().get_flags();
1165 new_flags = (jushort) k_new_method->access_flags().get_flags();
1166 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) {
1167 log_info(redefine, class, normalize)
1168 ("redefined class %s method %s modifiers error: modifiers changed from %d to %d",
1169 the_class->external_name(), k_old_method->name_and_sig_as_C_string(), old_flags, new_flags);
1170 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED;
1171 }
1172 {
1173 u2 new_num = k_new_method->method_idnum();
1174 u2 old_num = k_old_method->method_idnum();
1175 if (new_num != old_num) {
1176 Method* idnum_owner = scratch_class->method_with_idnum(old_num);
1177 if (idnum_owner != nullptr) {
1178 // There is already a method assigned this idnum -- switch them
1179 // Take current and original idnum from the new_method
1180 idnum_owner->set_method_idnum(new_num);
1181 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum());
1182 }
1183 // Take current and original idnum from the old_method
1184 k_new_method->set_method_idnum(old_num);
1185 k_new_method->set_orig_method_idnum(k_old_method->orig_method_idnum());
1186 if (thread->has_pending_exception()) {
1187 return JVMTI_ERROR_OUT_OF_MEMORY;
1188 }
1189 }
1190 }
1191 log_trace(redefine, class, normalize)
1192 ("Method matched: new: %s [%d] == old: %s [%d]",
1193 k_new_method->name_and_sig_as_C_string(), ni, k_old_method->name_and_sig_as_C_string(), oi);
1194 // advance to next pair of methods
1195 ++oi;
1196 ++ni;
1197 break;
1198 case added:
1199 // method added, see if it is OK
1200 if (!can_add_or_delete(k_new_method)) {
1201 log_info(redefine, class, normalize)
1202 ("redefined class %s methods error: added method: %s [%d]",
1203 the_class->external_name(), k_new_method->name_and_sig_as_C_string(), ni);
1204 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
1205 }
1206 {
1207 u2 num = the_class->next_method_idnum();
1208 if (num == ConstMethod::UNSET_IDNUM) {
1209 // cannot add any more methods
1210 log_info(redefine, class, normalize)
1211 ("redefined class %s methods error: can't create ID for new method %s [%d]",
1212 the_class->external_name(), k_new_method->name_and_sig_as_C_string(), ni);
1213 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
1214 }
1215 u2 new_num = k_new_method->method_idnum();
1216 Method* idnum_owner = scratch_class->method_with_idnum(num);
1217 if (idnum_owner != nullptr) {
1218 // There is already a method assigned this idnum -- switch them
1219 // Take current and original idnum from the new_method
1220 idnum_owner->set_method_idnum(new_num);
1221 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum());
1222 }
1223 k_new_method->set_method_idnum(num);
1224 k_new_method->set_orig_method_idnum(num);
1225 if (thread->has_pending_exception()) {
1226 return JVMTI_ERROR_OUT_OF_MEMORY;
1227 }
1228 }
1229 log_trace(redefine, class, normalize)
1230 ("Method added: new: %s [%d]", k_new_method->name_and_sig_as_C_string(), ni);
1231 ++ni; // advance to next new method
1232 break;
1233 case deleted:
1234 // method deleted, see if it is OK
1235 if (!can_add_or_delete(k_old_method)) {
1236 log_info(redefine, class, normalize)
1237 ("redefined class %s methods error: deleted method %s [%d]",
1238 the_class->external_name(), k_old_method->name_and_sig_as_C_string(), oi);
1239 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED;
1240 }
1241 log_trace(redefine, class, normalize)
1242 ("Method deleted: old: %s [%d]", k_old_method->name_and_sig_as_C_string(), oi);
1243 ++oi; // advance to next old method
1244 break;
1245 default:
1246 ShouldNotReachHere();
1247 }
1248 }
1249
1250 return JVMTI_ERROR_NONE;
1251 }
1252
1253
1254 // Find new constant pool index value for old constant pool index value
1255 // by searching the index map. Returns zero (0) if there is no mapped
1256 // value for the old constant pool index.
1257 u2 VM_RedefineClasses::find_new_index(int old_index) {
1258 if (_index_map_count == 0) {
1259 // map is empty so nothing can be found
1260 return 0;
1261 }
1262
1263 if (old_index < 1 || old_index >= _index_map_p->length()) {
1264 // The old_index is out of range so it is not mapped. This should
1265 // not happen in regular constant pool merging use, but it can
1266 // happen if a corrupt annotation is processed.
1267 return 0;
1268 }
1269
1270 int value = _index_map_p->at(old_index);
1271 if (value == -1) {
1272 // the old_index is not mapped
1273 return 0;
1274 }
1275
1276 // constant pool indices are u2, unless the merged constant pool overflows which
1277 // we don't check for.
1278 return checked_cast<u2>(value);
1279 } // end find_new_index()
1280
1281
1282 // Find new bootstrap specifier index value for old bootstrap specifier index
1283 // value by searching the index map. Returns unused index (-1) if there is
1284 // no mapped value for the old bootstrap specifier index.
1285 int VM_RedefineClasses::find_new_operand_index(int old_index) {
1286 if (_operands_index_map_count == 0) {
1287 // map is empty so nothing can be found
1288 return -1;
1289 }
1290
1291 if (old_index == -1 || old_index >= _operands_index_map_p->length()) {
1292 // The old_index is out of range so it is not mapped.
1293 // This should not happen in regular constant pool merging use.
1294 return -1;
1295 }
1296
1297 int value = _operands_index_map_p->at(old_index);
1298 if (value == -1) {
1299 // the old_index is not mapped
1300 return -1;
1301 }
1302
1303 return value;
1304 } // end find_new_operand_index()
1305
1306
1307 // Returns true if the current mismatch is due to a resolved/unresolved
1308 // class pair. Otherwise, returns false.
1309 bool VM_RedefineClasses::is_unresolved_class_mismatch(const constantPoolHandle& cp1,
1310 int index1, const constantPoolHandle& cp2, int index2) {
1311
1312 jbyte t1 = cp1->tag_at(index1).value();
1313 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) {
1314 return false; // wrong entry type; not our special case
1315 }
1316
1317 jbyte t2 = cp2->tag_at(index2).value();
1318 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) {
1319 return false; // wrong entry type; not our special case
1320 }
1321
1322 if (t1 == t2) {
1323 return false; // not a mismatch; not our special case
1324 }
1325
1326 char *s1 = cp1->klass_name_at(index1)->as_C_string();
1327 char *s2 = cp2->klass_name_at(index2)->as_C_string();
1328 if (strcmp(s1, s2) != 0) {
1329 return false; // strings don't match; not our special case
1330 }
1331
1332 return true; // made it through the gauntlet; this is our special case
1333 } // end is_unresolved_class_mismatch()
1334
1335
1336 // The bug 6214132 caused the verification to fail.
1337 // 1. What's done in RedefineClasses() before verification:
1338 // a) A reference to the class being redefined (_the_class) and a
1339 // reference to new version of the class (_scratch_class) are
1340 // saved here for use during the bytecode verification phase of
1341 // RedefineClasses.
1342 // b) The _java_mirror field from _the_class is copied to the
1343 // _java_mirror field in _scratch_class. This means that a jclass
1344 // returned for _the_class or _scratch_class will refer to the
1345 // same Java mirror. The verifier will see the "one true mirror"
1346 // for the class being verified.
1347 // 2. See comments in JvmtiThreadState for what is done during verification.
1348
1349 class RedefineVerifyMark : public StackObj {
1350 private:
1351 JvmtiThreadState* _state;
1352 Klass* _scratch_class;
1353 OopHandle _scratch_mirror;
1354
1355 public:
1356
1357 RedefineVerifyMark(Klass* the_class, Klass* scratch_class,
1358 JvmtiThreadState* state) : _state(state), _scratch_class(scratch_class)
1359 {
1360 _state->set_class_versions_map(the_class, scratch_class);
1361 _scratch_mirror = the_class->java_mirror_handle(); // this is a copy that is swapped
1362 _scratch_class->swap_java_mirror_handle(_scratch_mirror);
1363 }
1364
1365 ~RedefineVerifyMark() {
1366 // Restore the scratch class's mirror, so when scratch_class is removed
1367 // the correct mirror pointing to it can be cleared.
1368 _scratch_class->swap_java_mirror_handle(_scratch_mirror);
1369 _state->clear_class_versions_map();
1370 }
1371 };
1372
1373
1374 jvmtiError VM_RedefineClasses::load_new_class_versions() {
1375
1376 // For consistency allocate memory using os::malloc wrapper.
1377 _scratch_classes = (InstanceKlass**)
1378 os::malloc(sizeof(InstanceKlass*) * _class_count, mtClass);
1379 if (_scratch_classes == nullptr) {
1380 return JVMTI_ERROR_OUT_OF_MEMORY;
1381 }
1382 // Zero initialize the _scratch_classes array.
1383 for (int i = 0; i < _class_count; i++) {
1384 _scratch_classes[i] = nullptr;
1385 }
1386
1387 JavaThread* current = JavaThread::current();
1388 ResourceMark rm(current);
1389
1390 JvmtiThreadState *state = JvmtiThreadState::state_for(current);
1391 // state can only be null if the current thread is exiting which
1392 // should not happen since we're trying to do a RedefineClasses
1393 guarantee(state != nullptr, "exiting thread calling load_new_class_versions");
1394 for (int i = 0; i < _class_count; i++) {
1395 // Create HandleMark so that any handles created while loading new class
1396 // versions are deleted. Constant pools are deallocated while merging
1397 // constant pools
1398 HandleMark hm(current);
1399 InstanceKlass* the_class = get_ik(_class_defs[i].klass);
1400
1401 log_debug(redefine, class, load)
1402 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)",
1403 the_class->external_name(), _class_load_kind, os::available_memory() >> 10);
1404
1405 ClassFileStream st((u1*)_class_defs[i].class_bytes,
1406 _class_defs[i].class_byte_count,
1407 "__VM_RedefineClasses__",
1408 ClassFileStream::verify);
1409
1410 // Set redefined class handle in JvmtiThreadState class.
1411 // This redefined class is sent to agent event handler for class file
1412 // load hook event.
1413 state->set_class_being_redefined(the_class, _class_load_kind);
1414
1415 JavaThread* THREAD = current; // For exception macros.
1416 ExceptionMark em(THREAD);
1417 Handle protection_domain(THREAD, the_class->protection_domain());
1418 ClassLoadInfo cl_info(protection_domain);
1419 // Parse and create a class from the bytes, but this class isn't added
1420 // to the dictionary, so do not call resolve_from_stream.
1421 InstanceKlass* scratch_class = KlassFactory::create_from_stream(&st,
1422 the_class->name(),
1423 the_class->class_loader_data(),
1424 cl_info,
1425 THREAD);
1426
1427 // Clear class_being_redefined just to be sure.
1428 state->clear_class_being_redefined();
1429
1430 // TODO: if this is retransform, and nothing changed we can skip it
1431
1432 // Need to clean up allocated InstanceKlass if there's an error so assign
1433 // the result here. Caller deallocates all the scratch classes in case of
1434 // an error.
1435 _scratch_classes[i] = scratch_class;
1436
1437 if (HAS_PENDING_EXCEPTION) {
1438 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1439 log_info(redefine, class, load, exceptions)("create_from_stream exception: '%s'", ex_name->as_C_string());
1440 CLEAR_PENDING_EXCEPTION;
1441
1442 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) {
1443 return JVMTI_ERROR_UNSUPPORTED_VERSION;
1444 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) {
1445 return JVMTI_ERROR_INVALID_CLASS_FORMAT;
1446 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) {
1447 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION;
1448 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
1449 // The message will be "XXX (wrong name: YYY)"
1450 return JVMTI_ERROR_NAMES_DONT_MATCH;
1451 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1452 return JVMTI_ERROR_OUT_OF_MEMORY;
1453 } else { // Just in case more exceptions can be thrown..
1454 return JVMTI_ERROR_FAILS_VERIFICATION;
1455 }
1456 }
1457
1458 // Ensure class is linked before redefine
1459 if (!the_class->is_linked()) {
1460 the_class->link_class(THREAD);
1461 if (HAS_PENDING_EXCEPTION) {
1462 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1463 oop message = java_lang_Throwable::message(PENDING_EXCEPTION);
1464 if (message != nullptr) {
1465 char* ex_msg = java_lang_String::as_utf8_string(message);
1466 log_info(redefine, class, load, exceptions)("link_class exception: '%s %s'",
1467 ex_name->as_C_string(), ex_msg);
1468 } else {
1469 log_info(redefine, class, load, exceptions)("link_class exception: '%s'",
1470 ex_name->as_C_string());
1471 }
1472 CLEAR_PENDING_EXCEPTION;
1473 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1474 return JVMTI_ERROR_OUT_OF_MEMORY;
1475 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
1476 return JVMTI_ERROR_INVALID_CLASS;
1477 } else {
1478 return JVMTI_ERROR_INTERNAL;
1479 }
1480 }
1481 }
1482
1483 // Do the validity checks in compare_and_normalize_class_versions()
1484 // before verifying the byte codes. By doing these checks first, we
1485 // limit the number of functions that require redirection from
1486 // the_class to scratch_class. In particular, we don't have to
1487 // modify JNI GetSuperclass() and thus won't change its performance.
1488 jvmtiError res = compare_and_normalize_class_versions(the_class,
1489 scratch_class);
1490 if (res != JVMTI_ERROR_NONE) {
1491 return res;
1492 }
1493
1494 // verify what the caller passed us
1495 {
1496 // The bug 6214132 caused the verification to fail.
1497 // Information about the_class and scratch_class is temporarily
1498 // recorded into jvmtiThreadState. This data is used to redirect
1499 // the_class to scratch_class in the JVM_* functions called by the
1500 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed
1501 // description.
1502 RedefineVerifyMark rvm(the_class, scratch_class, state);
1503 Verifier::verify(scratch_class, true, THREAD);
1504 }
1505
1506 if (HAS_PENDING_EXCEPTION) {
1507 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1508 log_info(redefine, class, load, exceptions)("verify_byte_codes exception: '%s'", ex_name->as_C_string());
1509 CLEAR_PENDING_EXCEPTION;
1510 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1511 return JVMTI_ERROR_OUT_OF_MEMORY;
1512 } else {
1513 // tell the caller the bytecodes are bad
1514 return JVMTI_ERROR_FAILS_VERIFICATION;
1515 }
1516 }
1517
1518 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD);
1519 if (HAS_PENDING_EXCEPTION) {
1520 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1521 log_info(redefine, class, load, exceptions)("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string());
1522 CLEAR_PENDING_EXCEPTION;
1523 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1524 return JVMTI_ERROR_OUT_OF_MEMORY;
1525 } else {
1526 return JVMTI_ERROR_INTERNAL;
1527 }
1528 }
1529
1530 #ifdef ASSERT
1531 {
1532 // verify what we have done during constant pool merging
1533 {
1534 RedefineVerifyMark rvm(the_class, scratch_class, state);
1535 Verifier::verify(scratch_class, true, THREAD);
1536 }
1537
1538 if (HAS_PENDING_EXCEPTION) {
1539 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1540 log_info(redefine, class, load, exceptions)
1541 ("verify_byte_codes post merge-CP exception: '%s'", ex_name->as_C_string());
1542 CLEAR_PENDING_EXCEPTION;
1543 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1544 return JVMTI_ERROR_OUT_OF_MEMORY;
1545 } else {
1546 // tell the caller that constant pool merging screwed up
1547 return JVMTI_ERROR_INTERNAL;
1548 }
1549 }
1550 }
1551 #endif // ASSERT
1552
1553 Rewriter::rewrite(scratch_class, THREAD);
1554 if (!HAS_PENDING_EXCEPTION) {
1555 scratch_class->link_methods(THREAD);
1556 }
1557 if (HAS_PENDING_EXCEPTION) {
1558 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1559 log_info(redefine, class, load, exceptions)
1560 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string());
1561 CLEAR_PENDING_EXCEPTION;
1562 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1563 return JVMTI_ERROR_OUT_OF_MEMORY;
1564 } else {
1565 return JVMTI_ERROR_INTERNAL;
1566 }
1567 }
1568
1569 log_debug(redefine, class, load)
1570 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)", the_class->external_name(), os::available_memory() >> 10);
1571 }
1572
1573 return JVMTI_ERROR_NONE;
1574 }
1575
1576
1577 // Map old_index to new_index as needed. scratch_cp is only needed
1578 // for log calls.
1579 void VM_RedefineClasses::map_index(const constantPoolHandle& scratch_cp,
1580 int old_index, int new_index) {
1581 if (find_new_index(old_index) != 0) {
1582 // old_index is already mapped
1583 return;
1584 }
1585
1586 if (old_index == new_index) {
1587 // no mapping is needed
1588 return;
1589 }
1590
1591 _index_map_p->at_put(old_index, new_index);
1592 _index_map_count++;
1593
1594 log_trace(redefine, class, constantpool)
1595 ("mapped tag %d at index %d to %d", scratch_cp->tag_at(old_index).value(), old_index, new_index);
1596 } // end map_index()
1597
1598
1599 // Map old_index to new_index as needed.
1600 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) {
1601 if (find_new_operand_index(old_index) != -1) {
1602 // old_index is already mapped
1603 return;
1604 }
1605
1606 if (old_index == new_index) {
1607 // no mapping is needed
1608 return;
1609 }
1610
1611 _operands_index_map_p->at_put(old_index, new_index);
1612 _operands_index_map_count++;
1613
1614 log_trace(redefine, class, constantpool)("mapped bootstrap specifier at index %d to %d", old_index, new_index);
1615 } // end map_index()
1616
1617
1618 // Merge old_cp and scratch_cp and return the results of the merge via
1619 // merge_cp_p. The number of entries in *merge_cp_p is returned via
1620 // merge_cp_length_p. The entries in old_cp occupy the same locations
1621 // in *merge_cp_p. Also creates a map of indices from entries in
1622 // scratch_cp to the corresponding entry in *merge_cp_p. Index map
1623 // entries are only created for entries in scratch_cp that occupy a
1624 // different location in *merged_cp_p.
1625 bool VM_RedefineClasses::merge_constant_pools(const constantPoolHandle& old_cp,
1626 const constantPoolHandle& scratch_cp, constantPoolHandle *merge_cp_p,
1627 int *merge_cp_length_p, TRAPS) {
1628
1629 if (merge_cp_p == nullptr) {
1630 assert(false, "caller must provide scratch constantPool");
1631 return false; // robustness
1632 }
1633 if (merge_cp_length_p == nullptr) {
1634 assert(false, "caller must provide scratch CP length");
1635 return false; // robustness
1636 }
1637 // Worst case we need old_cp->length() + scratch_cp()->length(),
1638 // but the caller might be smart so make sure we have at least
1639 // the minimum.
1640 if ((*merge_cp_p)->length() < old_cp->length()) {
1641 assert(false, "merge area too small");
1642 return false; // robustness
1643 }
1644
1645 log_info(redefine, class, constantpool)("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(), scratch_cp->length());
1646
1647 {
1648 // Pass 0:
1649 // The old_cp is copied to *merge_cp_p; this means that any code
1650 // using old_cp does not have to change. This work looks like a
1651 // perfect fit for ConstantPool*::copy_cp_to(), but we need to
1652 // handle one special case:
1653 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass
1654 // This will make verification happy.
1655
1656 int old_i; // index into old_cp
1657
1658 // index zero (0) is not used in constantPools
1659 for (old_i = 1; old_i < old_cp->length(); old_i++) {
1660 // leave debugging crumb
1661 jbyte old_tag = old_cp->tag_at(old_i).value();
1662 switch (old_tag) {
1663 case JVM_CONSTANT_Class:
1664 case JVM_CONSTANT_UnresolvedClass:
1665 // revert the copy to JVM_CONSTANT_UnresolvedClass
1666 // May be resolving while calling this so do the same for
1667 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition)
1668 (*merge_cp_p)->temp_unresolved_klass_at_put(old_i,
1669 old_cp->klass_name_index_at(old_i));
1670 break;
1671
1672 case JVM_CONSTANT_Double:
1673 case JVM_CONSTANT_Long:
1674 // just copy the entry to *merge_cp_p, but double and long take
1675 // two constant pool entries
1676 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i);
1677 old_i++;
1678 break;
1679
1680 default:
1681 // just copy the entry to *merge_cp_p
1682 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i);
1683 break;
1684 }
1685 } // end for each old_cp entry
1686
1687 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_false);
1688 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_false);
1689
1690 // We don't need to sanity check that *merge_cp_length_p is within
1691 // *merge_cp_p bounds since we have the minimum on-entry check above.
1692 (*merge_cp_length_p) = old_i;
1693 }
1694
1695 // merge_cp_len should be the same as old_cp->length() at this point
1696 // so this trace message is really a "warm-and-breathing" message.
1697 log_debug(redefine, class, constantpool)("after pass 0: merge_cp_len=%d", *merge_cp_length_p);
1698
1699 int scratch_i; // index into scratch_cp
1700 {
1701 // Pass 1a:
1702 // Compare scratch_cp entries to the old_cp entries that we have
1703 // already copied to *merge_cp_p. In this pass, we are eliminating
1704 // exact duplicates (matching entry at same index) so we only
1705 // compare entries in the common indice range.
1706 int increment = 1;
1707 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length());
1708 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) {
1709 switch (scratch_cp->tag_at(scratch_i).value()) {
1710 case JVM_CONSTANT_Double:
1711 case JVM_CONSTANT_Long:
1712 // double and long take two constant pool entries
1713 increment = 2;
1714 break;
1715
1716 default:
1717 increment = 1;
1718 break;
1719 }
1720
1721 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p, scratch_i);
1722 if (match) {
1723 // found a match at the same index so nothing more to do
1724 continue;
1725 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i,
1726 *merge_cp_p, scratch_i)) {
1727 // The mismatch in compare_entry_to() above is because of a
1728 // resolved versus unresolved class entry at the same index
1729 // with the same string value. Since Pass 0 reverted any
1730 // class entries to unresolved class entries in *merge_cp_p,
1731 // we go with the unresolved class entry.
1732 continue;
1733 }
1734
1735 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p);
1736 if (found_i != 0) {
1737 guarantee(found_i != scratch_i,
1738 "compare_entry_to() and find_matching_entry() do not agree");
1739
1740 // Found a matching entry somewhere else in *merge_cp_p so
1741 // just need a mapping entry.
1742 map_index(scratch_cp, scratch_i, found_i);
1743 continue;
1744 }
1745
1746 // The find_matching_entry() call above could fail to find a match
1747 // due to a resolved versus unresolved class or string entry situation
1748 // like we solved above with the is_unresolved_*_mismatch() calls.
1749 // However, we would have to call is_unresolved_*_mismatch() over
1750 // all of *merge_cp_p (potentially) and that doesn't seem to be
1751 // worth the time.
1752
1753 // No match found so we have to append this entry and any unique
1754 // referenced entries to *merge_cp_p.
1755 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p);
1756 }
1757 }
1758
1759 log_debug(redefine, class, constantpool)
1760 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1761 *merge_cp_length_p, scratch_i, _index_map_count);
1762
1763 if (scratch_i < scratch_cp->length()) {
1764 // Pass 1b:
1765 // old_cp is smaller than scratch_cp so there are entries in
1766 // scratch_cp that we have not yet processed. We take care of
1767 // those now.
1768 int increment = 1;
1769 for (; scratch_i < scratch_cp->length(); scratch_i += increment) {
1770 switch (scratch_cp->tag_at(scratch_i).value()) {
1771 case JVM_CONSTANT_Double:
1772 case JVM_CONSTANT_Long:
1773 // double and long take two constant pool entries
1774 increment = 2;
1775 break;
1776
1777 default:
1778 increment = 1;
1779 break;
1780 }
1781
1782 int found_i =
1783 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p);
1784 if (found_i != 0) {
1785 // Found a matching entry somewhere else in *merge_cp_p so
1786 // just need a mapping entry.
1787 map_index(scratch_cp, scratch_i, found_i);
1788 continue;
1789 }
1790
1791 // No match found so we have to append this entry and any unique
1792 // referenced entries to *merge_cp_p.
1793 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p);
1794 }
1795
1796 log_debug(redefine, class, constantpool)
1797 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1798 *merge_cp_length_p, scratch_i, _index_map_count);
1799 }
1800 finalize_operands_merge(*merge_cp_p, CHECK_false);
1801
1802 return true;
1803 } // end merge_constant_pools()
1804
1805
1806 // Scoped object to clean up the constant pool(s) created for merging
1807 class MergeCPCleaner {
1808 ClassLoaderData* _loader_data;
1809 ConstantPool* _cp;
1810 ConstantPool* _scratch_cp;
1811 public:
1812 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) :
1813 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(nullptr) {}
1814 ~MergeCPCleaner() {
1815 _loader_data->add_to_deallocate_list(_cp);
1816 if (_scratch_cp != nullptr) {
1817 _loader_data->add_to_deallocate_list(_scratch_cp);
1818 }
1819 }
1820 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; }
1821 };
1822
1823 // Merge constant pools between the_class and scratch_class and
1824 // potentially rewrite bytecodes in scratch_class to use the merged
1825 // constant pool.
1826 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite(
1827 InstanceKlass* the_class, InstanceKlass* scratch_class,
1828 TRAPS) {
1829 // worst case merged constant pool length is old and new combined
1830 int merge_cp_length = the_class->constants()->length()
1831 + scratch_class->constants()->length();
1832
1833 // Constant pools are not easily reused so we allocate a new one
1834 // each time.
1835 // merge_cp is created unsafe for concurrent GC processing. It
1836 // should be marked safe before discarding it. Even though
1837 // garbage, if it crosses a card boundary, it may be scanned
1838 // in order to find the start of the first complete object on the card.
1839 ClassLoaderData* loader_data = the_class->class_loader_data();
1840 ConstantPool* merge_cp_oop =
1841 ConstantPool::allocate(loader_data,
1842 merge_cp_length,
1843 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1844 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop);
1845
1846 HandleMark hm(THREAD); // make sure handles are cleared before
1847 // MergeCPCleaner clears out merge_cp_oop
1848 constantPoolHandle merge_cp(THREAD, merge_cp_oop);
1849
1850 // Get constants() from the old class because it could have been rewritten
1851 // while we were at a safepoint allocating a new constant pool.
1852 constantPoolHandle old_cp(THREAD, the_class->constants());
1853 constantPoolHandle scratch_cp(THREAD, scratch_class->constants());
1854
1855 // If the length changed, the class was redefined out from under us. Return
1856 // an error.
1857 if (merge_cp_length != the_class->constants()->length()
1858 + scratch_class->constants()->length()) {
1859 return JVMTI_ERROR_INTERNAL;
1860 }
1861
1862 // Update the version number of the constant pools (may keep scratch_cp)
1863 merge_cp->increment_and_save_version(old_cp->version());
1864 scratch_cp->increment_and_save_version(old_cp->version());
1865
1866 ResourceMark rm(THREAD);
1867 _index_map_count = 0;
1868 _index_map_p = new intArray(scratch_cp->length(), scratch_cp->length(), -1);
1869
1870 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands());
1871 _operands_index_map_count = 0;
1872 int operands_index_map_len = ConstantPool::operand_array_length(scratch_cp->operands());
1873 _operands_index_map_p = new intArray(operands_index_map_len, operands_index_map_len, -1);
1874
1875 // reference to the cp holder is needed for copy_operands()
1876 merge_cp->set_pool_holder(scratch_class);
1877 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp,
1878 &merge_cp_length, THREAD);
1879 merge_cp->set_pool_holder(nullptr);
1880
1881 if (!result) {
1882 // The merge can fail due to memory allocation failure or due
1883 // to robustness checks.
1884 return JVMTI_ERROR_INTERNAL;
1885 }
1886
1887 // Set dynamic constants attribute from the original CP.
1888 if (old_cp->has_dynamic_constant()) {
1889 scratch_cp->set_has_dynamic_constant();
1890 }
1891
1892 log_info(redefine, class, constantpool)("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count);
1893
1894 if (_index_map_count == 0) {
1895 // there is nothing to map between the new and merged constant pools
1896
1897 // Copy attributes from scratch_cp to merge_cp
1898 merge_cp->copy_fields(scratch_cp());
1899
1900 if (old_cp->length() == scratch_cp->length()) {
1901 // The old and new constant pools are the same length and the
1902 // index map is empty. This means that the three constant pools
1903 // are equivalent (but not the same). Unfortunately, the new
1904 // constant pool has not gone through link resolution nor have
1905 // the new class bytecodes gone through constant pool cache
1906 // rewriting so we can't use the old constant pool with the new
1907 // class.
1908
1909 // toss the merged constant pool at return
1910 } else if (old_cp->length() < scratch_cp->length()) {
1911 // The old constant pool has fewer entries than the new constant
1912 // pool and the index map is empty. This means the new constant
1913 // pool is a superset of the old constant pool. However, the old
1914 // class bytecodes have already gone through constant pool cache
1915 // rewriting so we can't use the new constant pool with the old
1916 // class.
1917
1918 // toss the merged constant pool at return
1919 } else {
1920 // The old constant pool has more entries than the new constant
1921 // pool and the index map is empty. This means that both the old
1922 // and merged constant pools are supersets of the new constant
1923 // pool.
1924
1925 // Replace the new constant pool with a shrunken copy of the
1926 // merged constant pool
1927 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1928 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1929 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1930 // It can't be cleaned up while there are handles to it.
1931 cp_cleaner.add_scratch_cp(scratch_cp());
1932 }
1933 } else {
1934 if (log_is_enabled(Trace, redefine, class, constantpool)) {
1935 // don't want to loop unless we are tracing
1936 int count = 0;
1937 for (int i = 1; i < _index_map_p->length(); i++) {
1938 int value = _index_map_p->at(i);
1939
1940 if (value != -1) {
1941 log_trace(redefine, class, constantpool)("index_map[%d]: old=%d new=%d", count, i, value);
1942 count++;
1943 }
1944 }
1945 }
1946
1947 // We have entries mapped between the new and merged constant pools
1948 // so we have to rewrite some constant pool references.
1949 if (!rewrite_cp_refs(scratch_class)) {
1950 return JVMTI_ERROR_INTERNAL;
1951 }
1952
1953 // Copy attributes from scratch_cp to merge_cp (should be done after rewrite_cp_refs())
1954 merge_cp->copy_fields(scratch_cp());
1955
1956 // Replace the new constant pool with a shrunken copy of the
1957 // merged constant pool so now the rewritten bytecodes have
1958 // valid references; the previous new constant pool will get
1959 // GCed.
1960 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1961 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1962 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1963 // It can't be cleaned up while there are handles to it.
1964 cp_cleaner.add_scratch_cp(scratch_cp());
1965 }
1966
1967 return JVMTI_ERROR_NONE;
1968 } // end merge_cp_and_rewrite()
1969
1970
1971 // Rewrite constant pool references in klass scratch_class.
1972 bool VM_RedefineClasses::rewrite_cp_refs(InstanceKlass* scratch_class) {
1973
1974 // rewrite constant pool references in the nest attributes:
1975 if (!rewrite_cp_refs_in_nest_attributes(scratch_class)) {
1976 // propagate failure back to caller
1977 return false;
1978 }
1979
1980 // rewrite constant pool references in the Record attribute:
1981 if (!rewrite_cp_refs_in_record_attribute(scratch_class)) {
1982 // propagate failure back to caller
1983 return false;
1984 }
1985
1986 // rewrite constant pool references in the PermittedSubclasses attribute:
1987 if (!rewrite_cp_refs_in_permitted_subclasses_attribute(scratch_class)) {
1988 // propagate failure back to caller
1989 return false;
1990 }
1991
1992 // rewrite constant pool references in the Preload attribute:
1993 if (!rewrite_cp_refs_in_preload_attribute(scratch_class)) {
1994 // propagate failure back to caller
1995 return false;
1996 }
1997
1998 // rewrite constant pool references in the methods:
1999 if (!rewrite_cp_refs_in_methods(scratch_class)) {
2000 // propagate failure back to caller
2001 return false;
2002 }
2003
2004 // rewrite constant pool references in the class_annotations:
2005 if (!rewrite_cp_refs_in_class_annotations(scratch_class)) {
2006 // propagate failure back to caller
2007 return false;
2008 }
2009
2010 // rewrite constant pool references in the fields_annotations:
2011 if (!rewrite_cp_refs_in_fields_annotations(scratch_class)) {
2012 // propagate failure back to caller
2013 return false;
2014 }
2015
2016 // rewrite constant pool references in the methods_annotations:
2017 if (!rewrite_cp_refs_in_methods_annotations(scratch_class)) {
2018 // propagate failure back to caller
2019 return false;
2020 }
2021
2022 // rewrite constant pool references in the methods_parameter_annotations:
2023 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class)) {
2024 // propagate failure back to caller
2025 return false;
2026 }
2027
2028 // rewrite constant pool references in the methods_default_annotations:
2029 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class)) {
2030 // propagate failure back to caller
2031 return false;
2032 }
2033
2034 // rewrite constant pool references in the class_type_annotations:
2035 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class)) {
2036 // propagate failure back to caller
2037 return false;
2038 }
2039
2040 // rewrite constant pool references in the fields_type_annotations:
2041 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class)) {
2042 // propagate failure back to caller
2043 return false;
2044 }
2045
2046 // rewrite constant pool references in the methods_type_annotations:
2047 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class)) {
2048 // propagate failure back to caller
2049 return false;
2050 }
2051
2052 // There can be type annotations in the Code part of a method_info attribute.
2053 // These annotations are not accessible, even by reflection.
2054 // Currently they are not even parsed by the ClassFileParser.
2055 // If runtime access is added they will also need to be rewritten.
2056
2057 // rewrite source file name index:
2058 u2 source_file_name_idx = scratch_class->source_file_name_index();
2059 if (source_file_name_idx != 0) {
2060 u2 new_source_file_name_idx = find_new_index(source_file_name_idx);
2061 if (new_source_file_name_idx != 0) {
2062 scratch_class->set_source_file_name_index(new_source_file_name_idx);
2063 }
2064 }
2065
2066 // rewrite class generic signature index:
2067 u2 generic_signature_index = scratch_class->generic_signature_index();
2068 if (generic_signature_index != 0) {
2069 u2 new_generic_signature_index = find_new_index(generic_signature_index);
2070 if (new_generic_signature_index != 0) {
2071 scratch_class->set_generic_signature_index(new_generic_signature_index);
2072 }
2073 }
2074
2075 return true;
2076 } // end rewrite_cp_refs()
2077
2078 // Rewrite constant pool references in the NestHost and NestMembers attributes.
2079 bool VM_RedefineClasses::rewrite_cp_refs_in_nest_attributes(
2080 InstanceKlass* scratch_class) {
2081
2082 u2 cp_index = scratch_class->nest_host_index();
2083 if (cp_index != 0) {
2084 scratch_class->set_nest_host_index(find_new_index(cp_index));
2085 }
2086 Array<u2>* nest_members = scratch_class->nest_members();
2087 for (int i = 0; i < nest_members->length(); i++) {
2088 u2 cp_index = nest_members->at(i);
2089 nest_members->at_put(i, find_new_index(cp_index));
2090 }
2091 return true;
2092 }
2093
2094 // Rewrite constant pool references in the Record attribute.
2095 bool VM_RedefineClasses::rewrite_cp_refs_in_record_attribute(InstanceKlass* scratch_class) {
2096 Array<RecordComponent*>* components = scratch_class->record_components();
2097 if (components != nullptr) {
2098 for (int i = 0; i < components->length(); i++) {
2099 RecordComponent* component = components->at(i);
2100 u2 cp_index = component->name_index();
2101 component->set_name_index(find_new_index(cp_index));
2102 cp_index = component->descriptor_index();
2103 component->set_descriptor_index(find_new_index(cp_index));
2104 cp_index = component->generic_signature_index();
2105 if (cp_index != 0) {
2106 component->set_generic_signature_index(find_new_index(cp_index));
2107 }
2108
2109 AnnotationArray* annotations = component->annotations();
2110 if (annotations != nullptr && annotations->length() != 0) {
2111 int byte_i = 0; // byte index into annotations
2112 if (!rewrite_cp_refs_in_annotations_typeArray(annotations, byte_i)) {
2113 log_debug(redefine, class, annotation)("bad record_component_annotations at %d", i);
2114 // propagate failure back to caller
2115 return false;
2116 }
2117 }
2118
2119 AnnotationArray* type_annotations = component->type_annotations();
2120 if (type_annotations != nullptr && type_annotations->length() != 0) {
2121 int byte_i = 0; // byte index into annotations
2122 if (!rewrite_cp_refs_in_annotations_typeArray(type_annotations, byte_i)) {
2123 log_debug(redefine, class, annotation)("bad record_component_type_annotations at %d", i);
2124 // propagate failure back to caller
2125 return false;
2126 }
2127 }
2128 }
2129 }
2130 return true;
2131 }
2132
2133 // Rewrite constant pool references in the PermittedSubclasses attribute.
2134 bool VM_RedefineClasses::rewrite_cp_refs_in_permitted_subclasses_attribute(
2135 InstanceKlass* scratch_class) {
2136
2137 Array<u2>* permitted_subclasses = scratch_class->permitted_subclasses();
2138 assert(permitted_subclasses != nullptr, "unexpected null permitted_subclasses");
2139 for (int i = 0; i < permitted_subclasses->length(); i++) {
2140 u2 cp_index = permitted_subclasses->at(i);
2141 permitted_subclasses->at_put(i, find_new_index(cp_index));
2142 }
2143 return true;
2144 }
2145
2146 // Rewrite constant pool references in the Preload attribute.
2147 bool VM_RedefineClasses::rewrite_cp_refs_in_preload_attribute(
2148 InstanceKlass* scratch_class) {
2149
2150 Array<u2>* preload_classes = scratch_class->preload_classes();
2151 assert(preload_classes != nullptr, "unexpected null preload_classes");
2152 for (int i = 0; i < preload_classes->length(); i++) {
2153 u2 cp_index = preload_classes->at(i);
2154 preload_classes->at_put(i, find_new_index(cp_index));
2155 }
2156 return true;
2157 }
2158
2159 // Rewrite constant pool references in the methods.
2160 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(InstanceKlass* scratch_class) {
2161
2162 Array<Method*>* methods = scratch_class->methods();
2163
2164 if (methods == nullptr || methods->length() == 0) {
2165 // no methods so nothing to do
2166 return true;
2167 }
2168
2169 JavaThread* THREAD = JavaThread::current(); // For exception macros.
2170 ExceptionMark em(THREAD);
2171
2172 // rewrite constant pool references in the methods:
2173 for (int i = methods->length() - 1; i >= 0; i--) {
2174 methodHandle method(THREAD, methods->at(i));
2175 methodHandle new_method;
2176 rewrite_cp_refs_in_method(method, &new_method, THREAD);
2177 if (!new_method.is_null()) {
2178 // the method has been replaced so save the new method version
2179 // even in the case of an exception. original method is on the
2180 // deallocation list.
2181 methods->at_put(i, new_method());
2182 }
2183 if (HAS_PENDING_EXCEPTION) {
2184 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
2185 log_info(redefine, class, load, exceptions)("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string());
2186 // Need to clear pending exception here as the super caller sets
2187 // the JVMTI_ERROR_INTERNAL if the returned value is false.
2188 CLEAR_PENDING_EXCEPTION;
2189 return false;
2190 }
2191 }
2192
2193 return true;
2194 }
2195
2196
2197 // Rewrite constant pool references in the specific method. This code
2198 // was adapted from Rewriter::rewrite_method().
2199 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method,
2200 methodHandle *new_method_p, TRAPS) {
2201
2202 *new_method_p = methodHandle(); // default is no new method
2203
2204 // We cache a pointer to the bytecodes here in code_base. If GC
2205 // moves the Method*, then the bytecodes will also move which
2206 // will likely cause a crash. We create a NoSafepointVerifier
2207 // object to detect whether we pass a possible safepoint in this
2208 // code block.
2209 NoSafepointVerifier nsv;
2210
2211 // Bytecodes and their length
2212 address code_base = method->code_base();
2213 int code_length = method->code_size();
2214
2215 int bc_length;
2216 for (int bci = 0; bci < code_length; bci += bc_length) {
2217 address bcp = code_base + bci;
2218 Bytecodes::Code c = (Bytecodes::Code)(*bcp);
2219
2220 bc_length = Bytecodes::length_for(c);
2221 if (bc_length == 0) {
2222 // More complicated bytecodes report a length of zero so
2223 // we have to try again a slightly different way.
2224 bc_length = Bytecodes::length_at(method(), bcp);
2225 }
2226
2227 assert(bc_length != 0, "impossible bytecode length");
2228
2229 switch (c) {
2230 case Bytecodes::_ldc:
2231 {
2232 u1 cp_index = *(bcp + 1);
2233 u2 new_index = find_new_index(cp_index);
2234
2235 if (StressLdcRewrite && new_index == 0) {
2236 // If we are stressing ldc -> ldc_w rewriting, then we
2237 // always need a new_index value.
2238 new_index = cp_index;
2239 }
2240 if (new_index != 0) {
2241 // the original index is mapped so we have more work to do
2242 if (!StressLdcRewrite && new_index <= max_jubyte) {
2243 // The new value can still use ldc instead of ldc_w
2244 // unless we are trying to stress ldc -> ldc_w rewriting
2245 log_trace(redefine, class, constantpool)
2246 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index);
2247 // We checked that new_index fits in a u1 so this cast is safe
2248 *(bcp + 1) = (u1)new_index;
2249 } else {
2250 log_trace(redefine, class, constantpool)
2251 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index);
2252 // the new value needs ldc_w instead of ldc
2253 u_char inst_buffer[4]; // max instruction size is 4 bytes
2254 bcp = (address)inst_buffer;
2255 // construct new instruction sequence
2256 *bcp = Bytecodes::_ldc_w;
2257 bcp++;
2258 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w.
2259 // See comment below for difference between put_Java_u2()
2260 // and put_native_u2().
2261 Bytes::put_Java_u2(bcp, new_index);
2262
2263 Relocator rc(method, nullptr /* no RelocatorListener needed */);
2264 methodHandle m;
2265 {
2266 PauseNoSafepointVerifier pnsv(&nsv);
2267
2268 // ldc is 2 bytes and ldc_w is 3 bytes
2269 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK);
2270 }
2271
2272 // return the new method so that the caller can update
2273 // the containing class
2274 *new_method_p = method = m;
2275 // switch our bytecode processing loop from the old method
2276 // to the new method
2277 code_base = method->code_base();
2278 code_length = method->code_size();
2279 bcp = code_base + bci;
2280 c = (Bytecodes::Code)(*bcp);
2281 bc_length = Bytecodes::length_for(c);
2282 assert(bc_length != 0, "sanity check");
2283 } // end we need ldc_w instead of ldc
2284 } // end if there is a mapped index
2285 } break;
2286
2287 // these bytecodes have a two-byte constant pool index
2288 case Bytecodes::_anewarray : // fall through
2289 case Bytecodes::_checkcast : // fall through
2290 case Bytecodes::_getfield : // fall through
2291 case Bytecodes::_getstatic : // fall through
2292 case Bytecodes::_aconst_init : // fall through
2293 case Bytecodes::_withfield : // fall through
2294 case Bytecodes::_instanceof : // fall through
2295 case Bytecodes::_invokedynamic : // fall through
2296 case Bytecodes::_invokeinterface: // fall through
2297 case Bytecodes::_invokespecial : // fall through
2298 case Bytecodes::_invokestatic : // fall through
2299 case Bytecodes::_invokevirtual : // fall through
2300 case Bytecodes::_ldc_w : // fall through
2301 case Bytecodes::_ldc2_w : // fall through
2302 case Bytecodes::_multianewarray : // fall through
2303 case Bytecodes::_new : // fall through
2304 case Bytecodes::_putfield : // fall through
2305 case Bytecodes::_putstatic :
2306 {
2307 address p = bcp + 1;
2308 int cp_index = Bytes::get_Java_u2(p);
2309 u2 new_index = find_new_index(cp_index);
2310 if (new_index != 0) {
2311 // the original index is mapped so update w/ new value
2312 log_trace(redefine, class, constantpool)
2313 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),p2i(bcp), cp_index, new_index);
2314 // Rewriter::rewrite_method() uses put_native_u2() in this
2315 // situation because it is reusing the constant pool index
2316 // location for a native index into the ConstantPoolCache.
2317 // Since we are updating the constant pool index prior to
2318 // verification and ConstantPoolCache initialization, we
2319 // need to keep the new index in Java byte order.
2320 Bytes::put_Java_u2(p, new_index);
2321 }
2322 } break;
2323 default:
2324 break;
2325 }
2326 } // end for each bytecode
2327 } // end rewrite_cp_refs_in_method()
2328
2329
2330 // Rewrite constant pool references in the class_annotations field.
2331 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(InstanceKlass* scratch_class) {
2332
2333 AnnotationArray* class_annotations = scratch_class->class_annotations();
2334 if (class_annotations == nullptr || class_annotations->length() == 0) {
2335 // no class_annotations so nothing to do
2336 return true;
2337 }
2338
2339 log_debug(redefine, class, annotation)("class_annotations length=%d", class_annotations->length());
2340
2341 int byte_i = 0; // byte index into class_annotations
2342 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i);
2343 }
2344
2345
2346 // Rewrite constant pool references in an annotations typeArray. This
2347 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute
2348 // that is described in section 4.8.15 of the 2nd-edition of the VM spec:
2349 //
2350 // annotations_typeArray {
2351 // u2 num_annotations;
2352 // annotation annotations[num_annotations];
2353 // }
2354 //
2355 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray(
2356 AnnotationArray* annotations_typeArray, int &byte_i_ref) {
2357
2358 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2359 // not enough room for num_annotations field
2360 log_debug(redefine, class, annotation)("length() is too small for num_annotations field");
2361 return false;
2362 }
2363
2364 u2 num_annotations = Bytes::get_Java_u2((address)
2365 annotations_typeArray->adr_at(byte_i_ref));
2366 byte_i_ref += 2;
2367
2368 log_debug(redefine, class, annotation)("num_annotations=%d", num_annotations);
2369
2370 int calc_num_annotations = 0;
2371 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
2372 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, byte_i_ref)) {
2373 log_debug(redefine, class, annotation)("bad annotation_struct at %d", calc_num_annotations);
2374 // propagate failure back to caller
2375 return false;
2376 }
2377 }
2378 assert(num_annotations == calc_num_annotations, "sanity check");
2379
2380 return true;
2381 } // end rewrite_cp_refs_in_annotations_typeArray()
2382
2383
2384 // Rewrite constant pool references in the annotation struct portion of
2385 // an annotations_typeArray. This "structure" is from section 4.8.15 of
2386 // the 2nd-edition of the VM spec:
2387 //
2388 // struct annotation {
2389 // u2 type_index;
2390 // u2 num_element_value_pairs;
2391 // {
2392 // u2 element_name_index;
2393 // element_value value;
2394 // } element_value_pairs[num_element_value_pairs];
2395 // }
2396 //
2397 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct(
2398 AnnotationArray* annotations_typeArray, int &byte_i_ref) {
2399 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) {
2400 // not enough room for smallest annotation_struct
2401 log_debug(redefine, class, annotation)("length() is too small for annotation_struct");
2402 return false;
2403 }
2404
2405 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray,
2406 byte_i_ref, "type_index");
2407
2408 u2 num_element_value_pairs = Bytes::get_Java_u2((address)
2409 annotations_typeArray->adr_at(byte_i_ref));
2410 byte_i_ref += 2;
2411
2412 log_debug(redefine, class, annotation)
2413 ("type_index=%d num_element_value_pairs=%d", type_index, num_element_value_pairs);
2414
2415 int calc_num_element_value_pairs = 0;
2416 for (; calc_num_element_value_pairs < num_element_value_pairs;
2417 calc_num_element_value_pairs++) {
2418 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2419 // not enough room for another element_name_index, let alone
2420 // the rest of another component
2421 log_debug(redefine, class, annotation)("length() is too small for element_name_index");
2422 return false;
2423 }
2424
2425 u2 element_name_index = rewrite_cp_ref_in_annotation_data(
2426 annotations_typeArray, byte_i_ref,
2427 "element_name_index");
2428
2429 log_debug(redefine, class, annotation)("element_name_index=%d", element_name_index);
2430
2431 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, byte_i_ref)) {
2432 log_debug(redefine, class, annotation)("bad element_value at %d", calc_num_element_value_pairs);
2433 // propagate failure back to caller
2434 return false;
2435 }
2436 } // end for each component
2437 assert(num_element_value_pairs == calc_num_element_value_pairs,
2438 "sanity check");
2439
2440 return true;
2441 } // end rewrite_cp_refs_in_annotation_struct()
2442
2443
2444 // Rewrite a constant pool reference at the current position in
2445 // annotations_typeArray if needed. Returns the original constant
2446 // pool reference if a rewrite was not needed or the new constant
2447 // pool reference if a rewrite was needed.
2448 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data(
2449 AnnotationArray* annotations_typeArray, int &byte_i_ref,
2450 const char * trace_mesg) {
2451
2452 address cp_index_addr = (address)
2453 annotations_typeArray->adr_at(byte_i_ref);
2454 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr);
2455 u2 new_cp_index = find_new_index(old_cp_index);
2456 if (new_cp_index != 0) {
2457 log_debug(redefine, class, annotation)("mapped old %s=%d", trace_mesg, old_cp_index);
2458 Bytes::put_Java_u2(cp_index_addr, new_cp_index);
2459 old_cp_index = new_cp_index;
2460 }
2461 byte_i_ref += 2;
2462 return old_cp_index;
2463 }
2464
2465
2466 // Rewrite constant pool references in the element_value portion of an
2467 // annotations_typeArray. This "structure" is from section 4.8.15.1 of
2468 // the 2nd-edition of the VM spec:
2469 //
2470 // struct element_value {
2471 // u1 tag;
2472 // union {
2473 // u2 const_value_index;
2474 // {
2475 // u2 type_name_index;
2476 // u2 const_name_index;
2477 // } enum_const_value;
2478 // u2 class_info_index;
2479 // annotation annotation_value;
2480 // struct {
2481 // u2 num_values;
2482 // element_value values[num_values];
2483 // } array_value;
2484 // } value;
2485 // }
2486 //
2487 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value(
2488 AnnotationArray* annotations_typeArray, int &byte_i_ref) {
2489
2490 if ((byte_i_ref + 1) > annotations_typeArray->length()) {
2491 // not enough room for a tag let alone the rest of an element_value
2492 log_debug(redefine, class, annotation)("length() is too small for a tag");
2493 return false;
2494 }
2495
2496 u1 tag = annotations_typeArray->at(byte_i_ref);
2497 byte_i_ref++;
2498 log_debug(redefine, class, annotation)("tag='%c'", tag);
2499
2500 switch (tag) {
2501 // These BaseType tag values are from Table 4.2 in VM spec:
2502 case JVM_SIGNATURE_BYTE:
2503 case JVM_SIGNATURE_CHAR:
2504 case JVM_SIGNATURE_DOUBLE:
2505 case JVM_SIGNATURE_FLOAT:
2506 case JVM_SIGNATURE_INT:
2507 case JVM_SIGNATURE_LONG:
2508 case JVM_SIGNATURE_SHORT:
2509 case JVM_SIGNATURE_BOOLEAN:
2510
2511 // The remaining tag values are from Table 4.8 in the 2nd-edition of
2512 // the VM spec:
2513 case 's':
2514 {
2515 // For the above tag values (including the BaseType values),
2516 // value.const_value_index is right union field.
2517
2518 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2519 // not enough room for a const_value_index
2520 log_debug(redefine, class, annotation)("length() is too small for a const_value_index");
2521 return false;
2522 }
2523
2524 u2 const_value_index = rewrite_cp_ref_in_annotation_data(
2525 annotations_typeArray, byte_i_ref,
2526 "const_value_index");
2527
2528 log_debug(redefine, class, annotation)("const_value_index=%d", const_value_index);
2529 } break;
2530
2531 case 'e':
2532 {
2533 // for the above tag value, value.enum_const_value is right union field
2534
2535 if ((byte_i_ref + 4) > annotations_typeArray->length()) {
2536 // not enough room for a enum_const_value
2537 log_debug(redefine, class, annotation)("length() is too small for a enum_const_value");
2538 return false;
2539 }
2540
2541 u2 type_name_index = rewrite_cp_ref_in_annotation_data(
2542 annotations_typeArray, byte_i_ref,
2543 "type_name_index");
2544
2545 u2 const_name_index = rewrite_cp_ref_in_annotation_data(
2546 annotations_typeArray, byte_i_ref,
2547 "const_name_index");
2548
2549 log_debug(redefine, class, annotation)
2550 ("type_name_index=%d const_name_index=%d", type_name_index, const_name_index);
2551 } break;
2552
2553 case 'c':
2554 {
2555 // for the above tag value, value.class_info_index is right union field
2556
2557 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2558 // not enough room for a class_info_index
2559 log_debug(redefine, class, annotation)("length() is too small for a class_info_index");
2560 return false;
2561 }
2562
2563 u2 class_info_index = rewrite_cp_ref_in_annotation_data(
2564 annotations_typeArray, byte_i_ref,
2565 "class_info_index");
2566
2567 log_debug(redefine, class, annotation)("class_info_index=%d", class_info_index);
2568 } break;
2569
2570 case '@':
2571 // For the above tag value, value.attr_value is the right union
2572 // field. This is a nested annotation.
2573 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, byte_i_ref)) {
2574 // propagate failure back to caller
2575 return false;
2576 }
2577 break;
2578
2579 case JVM_SIGNATURE_ARRAY:
2580 {
2581 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2582 // not enough room for a num_values field
2583 log_debug(redefine, class, annotation)("length() is too small for a num_values field");
2584 return false;
2585 }
2586
2587 // For the above tag value, value.array_value is the right union
2588 // field. This is an array of nested element_value.
2589 u2 num_values = Bytes::get_Java_u2((address)
2590 annotations_typeArray->adr_at(byte_i_ref));
2591 byte_i_ref += 2;
2592 log_debug(redefine, class, annotation)("num_values=%d", num_values);
2593
2594 int calc_num_values = 0;
2595 for (; calc_num_values < num_values; calc_num_values++) {
2596 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, byte_i_ref)) {
2597 log_debug(redefine, class, annotation)("bad nested element_value at %d", calc_num_values);
2598 // propagate failure back to caller
2599 return false;
2600 }
2601 }
2602 assert(num_values == calc_num_values, "sanity check");
2603 } break;
2604
2605 default:
2606 log_debug(redefine, class, annotation)("bad tag=0x%x", tag);
2607 return false;
2608 } // end decode tag field
2609
2610 return true;
2611 } // end rewrite_cp_refs_in_element_value()
2612
2613
2614 // Rewrite constant pool references in a fields_annotations field.
2615 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations(
2616 InstanceKlass* scratch_class) {
2617
2618 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations();
2619
2620 if (fields_annotations == nullptr || fields_annotations->length() == 0) {
2621 // no fields_annotations so nothing to do
2622 return true;
2623 }
2624
2625 log_debug(redefine, class, annotation)("fields_annotations length=%d", fields_annotations->length());
2626
2627 for (int i = 0; i < fields_annotations->length(); i++) {
2628 AnnotationArray* field_annotations = fields_annotations->at(i);
2629 if (field_annotations == nullptr || field_annotations->length() == 0) {
2630 // this field does not have any annotations so skip it
2631 continue;
2632 }
2633
2634 int byte_i = 0; // byte index into field_annotations
2635 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i)) {
2636 log_debug(redefine, class, annotation)("bad field_annotations at %d", i);
2637 // propagate failure back to caller
2638 return false;
2639 }
2640 }
2641
2642 return true;
2643 } // end rewrite_cp_refs_in_fields_annotations()
2644
2645
2646 // Rewrite constant pool references in a methods_annotations field.
2647 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations(
2648 InstanceKlass* scratch_class) {
2649
2650 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2651 Method* m = scratch_class->methods()->at(i);
2652 AnnotationArray* method_annotations = m->constMethod()->method_annotations();
2653
2654 if (method_annotations == nullptr || method_annotations->length() == 0) {
2655 // this method does not have any annotations so skip it
2656 continue;
2657 }
2658
2659 int byte_i = 0; // byte index into method_annotations
2660 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i)) {
2661 log_debug(redefine, class, annotation)("bad method_annotations at %d", i);
2662 // propagate failure back to caller
2663 return false;
2664 }
2665 }
2666
2667 return true;
2668 } // end rewrite_cp_refs_in_methods_annotations()
2669
2670
2671 // Rewrite constant pool references in a methods_parameter_annotations
2672 // field. This "structure" is adapted from the
2673 // RuntimeVisibleParameterAnnotations_attribute described in section
2674 // 4.8.17 of the 2nd-edition of the VM spec:
2675 //
2676 // methods_parameter_annotations_typeArray {
2677 // u1 num_parameters;
2678 // {
2679 // u2 num_annotations;
2680 // annotation annotations[num_annotations];
2681 // } parameter_annotations[num_parameters];
2682 // }
2683 //
2684 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations(
2685 InstanceKlass* scratch_class) {
2686
2687 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2688 Method* m = scratch_class->methods()->at(i);
2689 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations();
2690 if (method_parameter_annotations == nullptr
2691 || method_parameter_annotations->length() == 0) {
2692 // this method does not have any parameter annotations so skip it
2693 continue;
2694 }
2695
2696 if (method_parameter_annotations->length() < 1) {
2697 // not enough room for a num_parameters field
2698 log_debug(redefine, class, annotation)("length() is too small for a num_parameters field at %d", i);
2699 return false;
2700 }
2701
2702 int byte_i = 0; // byte index into method_parameter_annotations
2703
2704 u1 num_parameters = method_parameter_annotations->at(byte_i);
2705 byte_i++;
2706
2707 log_debug(redefine, class, annotation)("num_parameters=%d", num_parameters);
2708
2709 int calc_num_parameters = 0;
2710 for (; calc_num_parameters < num_parameters; calc_num_parameters++) {
2711 if (!rewrite_cp_refs_in_annotations_typeArray(method_parameter_annotations, byte_i)) {
2712 log_debug(redefine, class, annotation)("bad method_parameter_annotations at %d", calc_num_parameters);
2713 // propagate failure back to caller
2714 return false;
2715 }
2716 }
2717 assert(num_parameters == calc_num_parameters, "sanity check");
2718 }
2719
2720 return true;
2721 } // end rewrite_cp_refs_in_methods_parameter_annotations()
2722
2723
2724 // Rewrite constant pool references in a methods_default_annotations
2725 // field. This "structure" is adapted from the AnnotationDefault_attribute
2726 // that is described in section 4.8.19 of the 2nd-edition of the VM spec:
2727 //
2728 // methods_default_annotations_typeArray {
2729 // element_value default_value;
2730 // }
2731 //
2732 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations(
2733 InstanceKlass* scratch_class) {
2734
2735 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2736 Method* m = scratch_class->methods()->at(i);
2737 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations();
2738 if (method_default_annotations == nullptr
2739 || method_default_annotations->length() == 0) {
2740 // this method does not have any default annotations so skip it
2741 continue;
2742 }
2743
2744 int byte_i = 0; // byte index into method_default_annotations
2745
2746 if (!rewrite_cp_refs_in_element_value(
2747 method_default_annotations, byte_i)) {
2748 log_debug(redefine, class, annotation)("bad default element_value at %d", i);
2749 // propagate failure back to caller
2750 return false;
2751 }
2752 }
2753
2754 return true;
2755 } // end rewrite_cp_refs_in_methods_default_annotations()
2756
2757
2758 // Rewrite constant pool references in a class_type_annotations field.
2759 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations(
2760 InstanceKlass* scratch_class) {
2761
2762 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations();
2763 if (class_type_annotations == nullptr || class_type_annotations->length() == 0) {
2764 // no class_type_annotations so nothing to do
2765 return true;
2766 }
2767
2768 log_debug(redefine, class, annotation)("class_type_annotations length=%d", class_type_annotations->length());
2769
2770 int byte_i = 0; // byte index into class_type_annotations
2771 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations,
2772 byte_i, "ClassFile");
2773 } // end rewrite_cp_refs_in_class_type_annotations()
2774
2775
2776 // Rewrite constant pool references in a fields_type_annotations field.
2777 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations(InstanceKlass* scratch_class) {
2778
2779 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations();
2780 if (fields_type_annotations == nullptr || fields_type_annotations->length() == 0) {
2781 // no fields_type_annotations so nothing to do
2782 return true;
2783 }
2784
2785 log_debug(redefine, class, annotation)("fields_type_annotations length=%d", fields_type_annotations->length());
2786
2787 for (int i = 0; i < fields_type_annotations->length(); i++) {
2788 AnnotationArray* field_type_annotations = fields_type_annotations->at(i);
2789 if (field_type_annotations == nullptr || field_type_annotations->length() == 0) {
2790 // this field does not have any annotations so skip it
2791 continue;
2792 }
2793
2794 int byte_i = 0; // byte index into field_type_annotations
2795 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations,
2796 byte_i, "field_info")) {
2797 log_debug(redefine, class, annotation)("bad field_type_annotations at %d", i);
2798 // propagate failure back to caller
2799 return false;
2800 }
2801 }
2802
2803 return true;
2804 } // end rewrite_cp_refs_in_fields_type_annotations()
2805
2806
2807 // Rewrite constant pool references in a methods_type_annotations field.
2808 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations(
2809 InstanceKlass* scratch_class) {
2810
2811 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2812 Method* m = scratch_class->methods()->at(i);
2813 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations();
2814
2815 if (method_type_annotations == nullptr || method_type_annotations->length() == 0) {
2816 // this method does not have any annotations so skip it
2817 continue;
2818 }
2819
2820 log_debug(redefine, class, annotation)("methods type_annotations length=%d", method_type_annotations->length());
2821
2822 int byte_i = 0; // byte index into method_type_annotations
2823 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations,
2824 byte_i, "method_info")) {
2825 log_debug(redefine, class, annotation)("bad method_type_annotations at %d", i);
2826 // propagate failure back to caller
2827 return false;
2828 }
2829 }
2830
2831 return true;
2832 } // end rewrite_cp_refs_in_methods_type_annotations()
2833
2834
2835 // Rewrite constant pool references in a type_annotations
2836 // field. This "structure" is adapted from the
2837 // RuntimeVisibleTypeAnnotations_attribute described in
2838 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2839 //
2840 // type_annotations_typeArray {
2841 // u2 num_annotations;
2842 // type_annotation annotations[num_annotations];
2843 // }
2844 //
2845 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray(
2846 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2847 const char * location_mesg) {
2848
2849 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2850 // not enough room for num_annotations field
2851 log_debug(redefine, class, annotation)("length() is too small for num_annotations field");
2852 return false;
2853 }
2854
2855 u2 num_annotations = Bytes::get_Java_u2((address)
2856 type_annotations_typeArray->adr_at(byte_i_ref));
2857 byte_i_ref += 2;
2858
2859 log_debug(redefine, class, annotation)("num_type_annotations=%d", num_annotations);
2860
2861 int calc_num_annotations = 0;
2862 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
2863 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray,
2864 byte_i_ref, location_mesg)) {
2865 log_debug(redefine, class, annotation)("bad type_annotation_struct at %d", calc_num_annotations);
2866 // propagate failure back to caller
2867 return false;
2868 }
2869 }
2870 assert(num_annotations == calc_num_annotations, "sanity check");
2871
2872 if (byte_i_ref != type_annotations_typeArray->length()) {
2873 log_debug(redefine, class, annotation)
2874 ("read wrong amount of bytes at end of processing type_annotations_typeArray (%d of %d bytes were read)",
2875 byte_i_ref, type_annotations_typeArray->length());
2876 return false;
2877 }
2878
2879 return true;
2880 } // end rewrite_cp_refs_in_type_annotations_typeArray()
2881
2882
2883 // Rewrite constant pool references in a type_annotation
2884 // field. This "structure" is adapted from the
2885 // RuntimeVisibleTypeAnnotations_attribute described in
2886 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2887 //
2888 // type_annotation {
2889 // u1 target_type;
2890 // union {
2891 // type_parameter_target;
2892 // supertype_target;
2893 // type_parameter_bound_target;
2894 // empty_target;
2895 // method_formal_parameter_target;
2896 // throws_target;
2897 // localvar_target;
2898 // catch_target;
2899 // offset_target;
2900 // type_argument_target;
2901 // } target_info;
2902 // type_path target_path;
2903 // annotation anno;
2904 // }
2905 //
2906 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct(
2907 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2908 const char * location_mesg) {
2909
2910 if (!skip_type_annotation_target(type_annotations_typeArray,
2911 byte_i_ref, location_mesg)) {
2912 return false;
2913 }
2914
2915 if (!skip_type_annotation_type_path(type_annotations_typeArray, byte_i_ref)) {
2916 return false;
2917 }
2918
2919 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray, byte_i_ref)) {
2920 return false;
2921 }
2922
2923 return true;
2924 } // end rewrite_cp_refs_in_type_annotation_struct()
2925
2926
2927 // Read, verify and skip over the target_type and target_info part
2928 // so that rewriting can continue in the later parts of the struct.
2929 //
2930 // u1 target_type;
2931 // union {
2932 // type_parameter_target;
2933 // supertype_target;
2934 // type_parameter_bound_target;
2935 // empty_target;
2936 // method_formal_parameter_target;
2937 // throws_target;
2938 // localvar_target;
2939 // catch_target;
2940 // offset_target;
2941 // type_argument_target;
2942 // } target_info;
2943 //
2944 bool VM_RedefineClasses::skip_type_annotation_target(
2945 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2946 const char * location_mesg) {
2947
2948 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2949 // not enough room for a target_type let alone the rest of a type_annotation
2950 log_debug(redefine, class, annotation)("length() is too small for a target_type");
2951 return false;
2952 }
2953
2954 u1 target_type = type_annotations_typeArray->at(byte_i_ref);
2955 byte_i_ref += 1;
2956 log_debug(redefine, class, annotation)("target_type=0x%.2x", target_type);
2957 log_debug(redefine, class, annotation)("location=%s", location_mesg);
2958
2959 // Skip over target_info
2960 switch (target_type) {
2961 case 0x00:
2962 // kind: type parameter declaration of generic class or interface
2963 // location: ClassFile
2964 case 0x01:
2965 // kind: type parameter declaration of generic method or constructor
2966 // location: method_info
2967
2968 {
2969 // struct:
2970 // type_parameter_target {
2971 // u1 type_parameter_index;
2972 // }
2973 //
2974 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2975 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_target");
2976 return false;
2977 }
2978
2979 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2980 byte_i_ref += 1;
2981
2982 log_debug(redefine, class, annotation)("type_parameter_target: type_parameter_index=%d", type_parameter_index);
2983 } break;
2984
2985 case 0x10:
2986 // kind: type in extends clause of class or interface declaration
2987 // or in implements clause of interface declaration
2988 // location: ClassFile
2989
2990 {
2991 // struct:
2992 // supertype_target {
2993 // u2 supertype_index;
2994 // }
2995 //
2996 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2997 log_debug(redefine, class, annotation)("length() is too small for a supertype_target");
2998 return false;
2999 }
3000
3001 u2 supertype_index = Bytes::get_Java_u2((address)
3002 type_annotations_typeArray->adr_at(byte_i_ref));
3003 byte_i_ref += 2;
3004
3005 log_debug(redefine, class, annotation)("supertype_target: supertype_index=%d", supertype_index);
3006 } break;
3007
3008 case 0x11:
3009 // kind: type in bound of type parameter declaration of generic class or interface
3010 // location: ClassFile
3011 case 0x12:
3012 // kind: type in bound of type parameter declaration of generic method or constructor
3013 // location: method_info
3014
3015 {
3016 // struct:
3017 // type_parameter_bound_target {
3018 // u1 type_parameter_index;
3019 // u1 bound_index;
3020 // }
3021 //
3022 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
3023 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_bound_target");
3024 return false;
3025 }
3026
3027 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
3028 byte_i_ref += 1;
3029 u1 bound_index = type_annotations_typeArray->at(byte_i_ref);
3030 byte_i_ref += 1;
3031
3032 log_debug(redefine, class, annotation)
3033 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d", type_parameter_index, bound_index);
3034 } break;
3035
3036 case 0x13:
3037 // kind: type in field declaration
3038 // location: field_info
3039 case 0x14:
3040 // kind: return type of method, or type of newly constructed object
3041 // location: method_info
3042 case 0x15:
3043 // kind: receiver type of method or constructor
3044 // location: method_info
3045
3046 {
3047 // struct:
3048 // empty_target {
3049 // }
3050 //
3051 log_debug(redefine, class, annotation)("empty_target");
3052 } break;
3053
3054 case 0x16:
3055 // kind: type in formal parameter declaration of method, constructor, or lambda expression
3056 // location: method_info
3057
3058 {
3059 // struct:
3060 // formal_parameter_target {
3061 // u1 formal_parameter_index;
3062 // }
3063 //
3064 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
3065 log_debug(redefine, class, annotation)("length() is too small for a formal_parameter_target");
3066 return false;
3067 }
3068
3069 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref);
3070 byte_i_ref += 1;
3071
3072 log_debug(redefine, class, annotation)
3073 ("formal_parameter_target: formal_parameter_index=%d", formal_parameter_index);
3074 } break;
3075
3076 case 0x17:
3077 // kind: type in throws clause of method or constructor
3078 // location: method_info
3079
3080 {
3081 // struct:
3082 // throws_target {
3083 // u2 throws_type_index
3084 // }
3085 //
3086 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
3087 log_debug(redefine, class, annotation)("length() is too small for a throws_target");
3088 return false;
3089 }
3090
3091 u2 throws_type_index = Bytes::get_Java_u2((address)
3092 type_annotations_typeArray->adr_at(byte_i_ref));
3093 byte_i_ref += 2;
3094
3095 log_debug(redefine, class, annotation)("throws_target: throws_type_index=%d", throws_type_index);
3096 } break;
3097
3098 case 0x40:
3099 // kind: type in local variable declaration
3100 // location: Code
3101 case 0x41:
3102 // kind: type in resource variable declaration
3103 // location: Code
3104
3105 {
3106 // struct:
3107 // localvar_target {
3108 // u2 table_length;
3109 // struct {
3110 // u2 start_pc;
3111 // u2 length;
3112 // u2 index;
3113 // } table[table_length];
3114 // }
3115 //
3116 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
3117 // not enough room for a table_length let alone the rest of a localvar_target
3118 log_debug(redefine, class, annotation)("length() is too small for a localvar_target table_length");
3119 return false;
3120 }
3121
3122 u2 table_length = Bytes::get_Java_u2((address)
3123 type_annotations_typeArray->adr_at(byte_i_ref));
3124 byte_i_ref += 2;
3125
3126 log_debug(redefine, class, annotation)("localvar_target: table_length=%d", table_length);
3127
3128 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry
3129 int table_size = table_length * table_struct_size;
3130
3131 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) {
3132 // not enough room for a table
3133 log_debug(redefine, class, annotation)("length() is too small for a table array of length %d", table_length);
3134 return false;
3135 }
3136
3137 // Skip over table
3138 byte_i_ref += table_size;
3139 } break;
3140
3141 case 0x42:
3142 // kind: type in exception parameter declaration
3143 // location: Code
3144
3145 {
3146 // struct:
3147 // catch_target {
3148 // u2 exception_table_index;
3149 // }
3150 //
3151 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
3152 log_debug(redefine, class, annotation)("length() is too small for a catch_target");
3153 return false;
3154 }
3155
3156 u2 exception_table_index = Bytes::get_Java_u2((address)
3157 type_annotations_typeArray->adr_at(byte_i_ref));
3158 byte_i_ref += 2;
3159
3160 log_debug(redefine, class, annotation)("catch_target: exception_table_index=%d", exception_table_index);
3161 } break;
3162
3163 case 0x43:
3164 // kind: type in instanceof expression
3165 // location: Code
3166 case 0x44:
3167 // kind: type in new expression
3168 // location: Code
3169 case 0x45:
3170 // kind: type in method reference expression using ::new
3171 // location: Code
3172 case 0x46:
3173 // kind: type in method reference expression using ::Identifier
3174 // location: Code
3175
3176 {
3177 // struct:
3178 // offset_target {
3179 // u2 offset;
3180 // }
3181 //
3182 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
3183 log_debug(redefine, class, annotation)("length() is too small for a offset_target");
3184 return false;
3185 }
3186
3187 u2 offset = Bytes::get_Java_u2((address)
3188 type_annotations_typeArray->adr_at(byte_i_ref));
3189 byte_i_ref += 2;
3190
3191 log_debug(redefine, class, annotation)("offset_target: offset=%d", offset);
3192 } break;
3193
3194 case 0x47:
3195 // kind: type in cast expression
3196 // location: Code
3197 case 0x48:
3198 // kind: type argument for generic constructor in new expression or
3199 // explicit constructor invocation statement
3200 // location: Code
3201 case 0x49:
3202 // kind: type argument for generic method in method invocation expression
3203 // location: Code
3204 case 0x4A:
3205 // kind: type argument for generic constructor in method reference expression using ::new
3206 // location: Code
3207 case 0x4B:
3208 // kind: type argument for generic method in method reference expression using ::Identifier
3209 // location: Code
3210
3211 {
3212 // struct:
3213 // type_argument_target {
3214 // u2 offset;
3215 // u1 type_argument_index;
3216 // }
3217 //
3218 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) {
3219 log_debug(redefine, class, annotation)("length() is too small for a type_argument_target");
3220 return false;
3221 }
3222
3223 u2 offset = Bytes::get_Java_u2((address)
3224 type_annotations_typeArray->adr_at(byte_i_ref));
3225 byte_i_ref += 2;
3226 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
3227 byte_i_ref += 1;
3228
3229 log_debug(redefine, class, annotation)
3230 ("type_argument_target: offset=%d, type_argument_index=%d", offset, type_argument_index);
3231 } break;
3232
3233 default:
3234 log_debug(redefine, class, annotation)("unknown target_type");
3235 #ifdef ASSERT
3236 ShouldNotReachHere();
3237 #endif
3238 return false;
3239 }
3240
3241 return true;
3242 } // end skip_type_annotation_target()
3243
3244
3245 // Read, verify and skip over the type_path part so that rewriting
3246 // can continue in the later parts of the struct.
3247 //
3248 // type_path {
3249 // u1 path_length;
3250 // {
3251 // u1 type_path_kind;
3252 // u1 type_argument_index;
3253 // } path[path_length];
3254 // }
3255 //
3256 bool VM_RedefineClasses::skip_type_annotation_type_path(
3257 AnnotationArray* type_annotations_typeArray, int &byte_i_ref) {
3258
3259 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
3260 // not enough room for a path_length let alone the rest of the type_path
3261 log_debug(redefine, class, annotation)("length() is too small for a type_path");
3262 return false;
3263 }
3264
3265 u1 path_length = type_annotations_typeArray->at(byte_i_ref);
3266 byte_i_ref += 1;
3267
3268 log_debug(redefine, class, annotation)("type_path: path_length=%d", path_length);
3269
3270 int calc_path_length = 0;
3271 for (; calc_path_length < path_length; calc_path_length++) {
3272 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) {
3273 // not enough room for a path
3274 log_debug(redefine, class, annotation)
3275 ("length() is too small for path entry %d of %d", calc_path_length, path_length);
3276 return false;
3277 }
3278
3279 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref);
3280 byte_i_ref += 1;
3281 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
3282 byte_i_ref += 1;
3283
3284 log_debug(redefine, class, annotation)
3285 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d",
3286 calc_path_length, type_path_kind, type_argument_index);
3287
3288 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) {
3289 // not enough room for a path
3290 log_debug(redefine, class, annotation)("inconsistent type_path values");
3291 return false;
3292 }
3293 }
3294 assert(path_length == calc_path_length, "sanity check");
3295
3296 return true;
3297 } // end skip_type_annotation_type_path()
3298
3299
3300 // Rewrite constant pool references in the method's stackmap table.
3301 // These "structures" are adapted from the StackMapTable_attribute that
3302 // is described in section 4.8.4 of the 6.0 version of the VM spec
3303 // (dated 2005.10.26):
3304 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
3305 //
3306 // stack_map {
3307 // u2 number_of_entries;
3308 // stack_map_frame entries[number_of_entries];
3309 // }
3310 //
3311 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table(
3312 const methodHandle& method) {
3313
3314 if (!method->has_stackmap_table()) {
3315 return;
3316 }
3317
3318 AnnotationArray* stackmap_data = method->stackmap_data();
3319 address stackmap_p = (address)stackmap_data->adr_at(0);
3320 address stackmap_end = stackmap_p + stackmap_data->length();
3321
3322 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries");
3323 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p);
3324 stackmap_p += 2;
3325
3326 log_debug(redefine, class, stackmap)("number_of_entries=%u", number_of_entries);
3327
3328 // walk through each stack_map_frame
3329 u2 calc_number_of_entries = 0;
3330 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) {
3331 // The stack_map_frame structure is a u1 frame_type followed by
3332 // 0 or more bytes of data:
3333 //
3334 // union stack_map_frame {
3335 // same_frame;
3336 // same_locals_1_stack_item_frame;
3337 // same_locals_1_stack_item_frame_extended;
3338 // chop_frame;
3339 // same_frame_extended;
3340 // append_frame;
3341 // full_frame;
3342 // }
3343
3344 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type");
3345 u1 frame_type = *stackmap_p;
3346 stackmap_p++;
3347
3348 // same_frame {
3349 // u1 frame_type = SAME; /* 0-63 */
3350 // }
3351 if (frame_type <= 63) {
3352 // nothing more to do for same_frame
3353 }
3354
3355 // same_locals_1_stack_item_frame {
3356 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */
3357 // verification_type_info stack[1];
3358 // }
3359 else if (frame_type >= 64 && frame_type <= 127) {
3360 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3361 calc_number_of_entries, frame_type);
3362 }
3363
3364 // reserved for future use
3365 else if (frame_type >= 128 && frame_type <= 246) {
3366 // nothing more to do for reserved frame_types
3367 }
3368
3369 // same_locals_1_stack_item_frame_extended {
3370 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */
3371 // u2 offset_delta;
3372 // verification_type_info stack[1];
3373 // }
3374 else if (frame_type == 247) {
3375 stackmap_p += 2;
3376 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3377 calc_number_of_entries, frame_type);
3378 }
3379
3380 // chop_frame {
3381 // u1 frame_type = CHOP; /* 248-250 */
3382 // u2 offset_delta;
3383 // }
3384 else if (frame_type >= 248 && frame_type <= 250) {
3385 stackmap_p += 2;
3386 }
3387
3388 // same_frame_extended {
3389 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/
3390 // u2 offset_delta;
3391 // }
3392 else if (frame_type == 251) {
3393 stackmap_p += 2;
3394 }
3395
3396 // append_frame {
3397 // u1 frame_type = APPEND; /* 252-254 */
3398 // u2 offset_delta;
3399 // verification_type_info locals[frame_type - 251];
3400 // }
3401 else if (frame_type >= 252 && frame_type <= 254) {
3402 assert(stackmap_p + 2 <= stackmap_end,
3403 "no room for offset_delta");
3404 stackmap_p += 2;
3405 u1 len = frame_type - 251;
3406 for (u1 i = 0; i < len; i++) {
3407 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3408 calc_number_of_entries, frame_type);
3409 }
3410 }
3411
3412 // full_frame {
3413 // u1 frame_type = FULL_FRAME; /* 255 */
3414 // u2 offset_delta;
3415 // u2 number_of_locals;
3416 // verification_type_info locals[number_of_locals];
3417 // u2 number_of_stack_items;
3418 // verification_type_info stack[number_of_stack_items];
3419 // }
3420 else if (frame_type == 255) {
3421 assert(stackmap_p + 2 + 2 <= stackmap_end,
3422 "no room for smallest full_frame");
3423 stackmap_p += 2;
3424
3425 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p);
3426 stackmap_p += 2;
3427
3428 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) {
3429 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3430 calc_number_of_entries, frame_type);
3431 }
3432
3433 // Use the largest size for the number_of_stack_items, but only get
3434 // the right number of bytes.
3435 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p);
3436 stackmap_p += 2;
3437
3438 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) {
3439 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3440 calc_number_of_entries, frame_type);
3441 }
3442 }
3443 } // end while there is a stack_map_frame
3444 assert(number_of_entries == calc_number_of_entries, "sanity check");
3445 } // end rewrite_cp_refs_in_stack_map_table()
3446
3447
3448 // Rewrite constant pool references in the verification type info
3449 // portion of the method's stackmap table. These "structures" are
3450 // adapted from the StackMapTable_attribute that is described in
3451 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26):
3452 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
3453 //
3454 // The verification_type_info structure is a u1 tag followed by 0 or
3455 // more bytes of data:
3456 //
3457 // union verification_type_info {
3458 // Top_variable_info;
3459 // Integer_variable_info;
3460 // Float_variable_info;
3461 // Long_variable_info;
3462 // Double_variable_info;
3463 // Null_variable_info;
3464 // UninitializedThis_variable_info;
3465 // Object_variable_info;
3466 // Uninitialized_variable_info;
3467 // }
3468 //
3469 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info(
3470 address& stackmap_p_ref, address stackmap_end, u2 frame_i,
3471 u1 frame_type) {
3472
3473 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag");
3474 u1 tag = *stackmap_p_ref;
3475 stackmap_p_ref++;
3476
3477 switch (tag) {
3478 // Top_variable_info {
3479 // u1 tag = ITEM_Top; /* 0 */
3480 // }
3481 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top
3482 case 0: // fall through
3483
3484 // Integer_variable_info {
3485 // u1 tag = ITEM_Integer; /* 1 */
3486 // }
3487 case ITEM_Integer: // fall through
3488
3489 // Float_variable_info {
3490 // u1 tag = ITEM_Float; /* 2 */
3491 // }
3492 case ITEM_Float: // fall through
3493
3494 // Double_variable_info {
3495 // u1 tag = ITEM_Double; /* 3 */
3496 // }
3497 case ITEM_Double: // fall through
3498
3499 // Long_variable_info {
3500 // u1 tag = ITEM_Long; /* 4 */
3501 // }
3502 case ITEM_Long: // fall through
3503
3504 // Null_variable_info {
3505 // u1 tag = ITEM_Null; /* 5 */
3506 // }
3507 case ITEM_Null: // fall through
3508
3509 // UninitializedThis_variable_info {
3510 // u1 tag = ITEM_UninitializedThis; /* 6 */
3511 // }
3512 case ITEM_UninitializedThis:
3513 // nothing more to do for the above tag types
3514 break;
3515
3516 // Object_variable_info {
3517 // u1 tag = ITEM_Object; /* 7 */
3518 // u2 cpool_index;
3519 // }
3520 case ITEM_Object:
3521 {
3522 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index");
3523 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref);
3524 u2 new_cp_index = find_new_index(cpool_index);
3525 if (new_cp_index != 0) {
3526 log_debug(redefine, class, stackmap)("mapped old cpool_index=%d", cpool_index);
3527 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
3528 cpool_index = new_cp_index;
3529 }
3530 stackmap_p_ref += 2;
3531
3532 log_debug(redefine, class, stackmap)
3533 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i, frame_type, cpool_index);
3534 } break;
3535
3536 // Uninitialized_variable_info {
3537 // u1 tag = ITEM_Uninitialized; /* 8 */
3538 // u2 offset;
3539 // }
3540 case ITEM_Uninitialized:
3541 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset");
3542 stackmap_p_ref += 2;
3543 break;
3544
3545 default:
3546 log_debug(redefine, class, stackmap)("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag);
3547 ShouldNotReachHere();
3548 break;
3549 } // end switch (tag)
3550 } // end rewrite_cp_refs_in_verification_type_info()
3551
3552
3553 // Change the constant pool associated with klass scratch_class to scratch_cp.
3554 // scratch_cp_length elements are copied from scratch_cp to a smaller constant pool
3555 // and the smaller constant pool is associated with scratch_class.
3556 void VM_RedefineClasses::set_new_constant_pool(
3557 ClassLoaderData* loader_data,
3558 InstanceKlass* scratch_class, constantPoolHandle scratch_cp,
3559 int scratch_cp_length, TRAPS) {
3560 assert(scratch_cp->length() >= scratch_cp_length, "sanity check");
3561
3562 // scratch_cp is a merged constant pool and has enough space for a
3563 // worst case merge situation. We want to associate the minimum
3564 // sized constant pool with the klass to save space.
3565 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK);
3566 constantPoolHandle smaller_cp(THREAD, cp);
3567
3568 // preserve version() value in the smaller copy
3569 int version = scratch_cp->version();
3570 assert(version != 0, "sanity check");
3571 smaller_cp->set_version(version);
3572
3573 // attach klass to new constant pool
3574 // reference to the cp holder is needed for copy_operands()
3575 smaller_cp->set_pool_holder(scratch_class);
3576
3577 smaller_cp->copy_fields(scratch_cp());
3578
3579 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
3580 if (HAS_PENDING_EXCEPTION) {
3581 // Exception is handled in the caller
3582 loader_data->add_to_deallocate_list(smaller_cp());
3583 return;
3584 }
3585 scratch_cp = smaller_cp;
3586
3587 // attach new constant pool to klass
3588 scratch_class->set_constants(scratch_cp());
3589 scratch_cp->initialize_unresolved_klasses(loader_data, CHECK);
3590
3591 int i; // for portability
3592
3593 // update each field in klass to use new constant pool indices as needed
3594 int java_fields;
3595 int injected_fields;
3596 bool update_required = false;
3597 GrowableArray<FieldInfo>* fields = FieldInfoStream::create_FieldInfoArray(scratch_class->fieldinfo_stream(), &java_fields, &injected_fields);
3598 for (int i = 0; i < java_fields; i++) {
3599 FieldInfo* fi = fields->adr_at(i);
3600 jshort cur_index = fi->name_index();
3601 jshort new_index = find_new_index(cur_index);
3602 if (new_index != 0) {
3603 log_trace(redefine, class, constantpool)("field-name_index change: %d to %d", cur_index, new_index);
3604 fi->set_name_index(new_index);
3605 update_required = true;
3606 }
3607 cur_index = fi->signature_index();
3608 new_index = find_new_index(cur_index);
3609 if (new_index != 0) {
3610 log_trace(redefine, class, constantpool)("field-signature_index change: %d to %d", cur_index, new_index);
3611 fi->set_signature_index(new_index);
3612 update_required = true;
3613 }
3614 cur_index = fi->initializer_index();
3615 new_index = find_new_index(cur_index);
3616 if (new_index != 0) {
3617 log_trace(redefine, class, constantpool)("field-initval_index change: %d to %d", cur_index, new_index);
3618 fi->set_initializer_index(new_index);
3619 update_required = true;
3620 }
3621 cur_index = fi->generic_signature_index();
3622 new_index = find_new_index(cur_index);
3623 if (new_index != 0) {
3624 log_trace(redefine, class, constantpool)("field-generic_signature change: %d to %d", cur_index, new_index);
3625 fi->set_generic_signature_index(new_index);
3626 update_required = true;
3627 }
3628 }
3629 if (update_required) {
3630 Array<u1>* old_stream = scratch_class->fieldinfo_stream();
3631 assert(fields->length() == (java_fields + injected_fields), "Must be");
3632 Array<u1>* new_fis = FieldInfoStream::create_FieldInfoStream(fields, java_fields, injected_fields, scratch_class->class_loader_data(), CHECK);
3633 scratch_class->set_fieldinfo_stream(new_fis);
3634 MetadataFactory::free_array<u1>(scratch_class->class_loader_data(), old_stream);
3635 }
3636
3637 // Update constant pool indices in the inner classes info to use
3638 // new constant indices as needed. The inner classes info is a
3639 // quadruple:
3640 // (inner_class_info, outer_class_info, inner_name, inner_access_flags)
3641 InnerClassesIterator iter(scratch_class);
3642 for (; !iter.done(); iter.next()) {
3643 int cur_index = iter.inner_class_info_index();
3644 if (cur_index == 0) {
3645 continue; // JVM spec. allows null inner class refs so skip it
3646 }
3647 u2 new_index = find_new_index(cur_index);
3648 if (new_index != 0) {
3649 log_trace(redefine, class, constantpool)("inner_class_info change: %d to %d", cur_index, new_index);
3650 iter.set_inner_class_info_index(new_index);
3651 }
3652 cur_index = iter.outer_class_info_index();
3653 new_index = find_new_index(cur_index);
3654 if (new_index != 0) {
3655 log_trace(redefine, class, constantpool)("outer_class_info change: %d to %d", cur_index, new_index);
3656 iter.set_outer_class_info_index(new_index);
3657 }
3658 cur_index = iter.inner_name_index();
3659 new_index = find_new_index(cur_index);
3660 if (new_index != 0) {
3661 log_trace(redefine, class, constantpool)("inner_name change: %d to %d", cur_index, new_index);
3662 iter.set_inner_name_index(new_index);
3663 }
3664 } // end for each inner class
3665
3666 // Attach each method in klass to the new constant pool and update
3667 // to use new constant pool indices as needed:
3668 Array<Method*>* methods = scratch_class->methods();
3669 for (i = methods->length() - 1; i >= 0; i--) {
3670 methodHandle method(THREAD, methods->at(i));
3671 method->set_constants(scratch_cp());
3672
3673 u2 new_index = find_new_index(method->name_index());
3674 if (new_index != 0) {
3675 log_trace(redefine, class, constantpool)
3676 ("method-name_index change: %d to %d", method->name_index(), new_index);
3677 method->set_name_index(new_index);
3678 }
3679 new_index = find_new_index(method->signature_index());
3680 if (new_index != 0) {
3681 log_trace(redefine, class, constantpool)
3682 ("method-signature_index change: %d to %d", method->signature_index(), new_index);
3683 method->set_signature_index(new_index);
3684 }
3685 new_index = find_new_index(method->generic_signature_index());
3686 if (new_index != 0) {
3687 log_trace(redefine, class, constantpool)
3688 ("method-generic_signature_index change: %d to %d", method->generic_signature_index(), new_index);
3689 method->constMethod()->set_generic_signature_index(new_index);
3690 }
3691
3692 // Update constant pool indices in the method's checked exception
3693 // table to use new constant indices as needed.
3694 int cext_length = method->checked_exceptions_length();
3695 if (cext_length > 0) {
3696 CheckedExceptionElement * cext_table =
3697 method->checked_exceptions_start();
3698 for (int j = 0; j < cext_length; j++) {
3699 int cur_index = cext_table[j].class_cp_index;
3700 int new_index = find_new_index(cur_index);
3701 if (new_index != 0) {
3702 log_trace(redefine, class, constantpool)("cext-class_cp_index change: %d to %d", cur_index, new_index);
3703 cext_table[j].class_cp_index = (u2)new_index;
3704 }
3705 } // end for each checked exception table entry
3706 } // end if there are checked exception table entries
3707
3708 // Update each catch type index in the method's exception table
3709 // to use new constant pool indices as needed. The exception table
3710 // holds quadruple entries of the form:
3711 // (beg_bci, end_bci, handler_bci, klass_index)
3712
3713 ExceptionTable ex_table(method());
3714 int ext_length = ex_table.length();
3715
3716 for (int j = 0; j < ext_length; j ++) {
3717 int cur_index = ex_table.catch_type_index(j);
3718 u2 new_index = find_new_index(cur_index);
3719 if (new_index != 0) {
3720 log_trace(redefine, class, constantpool)("ext-klass_index change: %d to %d", cur_index, new_index);
3721 ex_table.set_catch_type_index(j, new_index);
3722 }
3723 } // end for each exception table entry
3724
3725 // Update constant pool indices in the method's local variable
3726 // table to use new constant indices as needed. The local variable
3727 // table hold sextuple entries of the form:
3728 // (start_pc, length, name_index, descriptor_index, signature_index, slot)
3729 int lvt_length = method->localvariable_table_length();
3730 if (lvt_length > 0) {
3731 LocalVariableTableElement * lv_table =
3732 method->localvariable_table_start();
3733 for (int j = 0; j < lvt_length; j++) {
3734 int cur_index = lv_table[j].name_cp_index;
3735 int new_index = find_new_index(cur_index);
3736 if (new_index != 0) {
3737 log_trace(redefine, class, constantpool)("lvt-name_cp_index change: %d to %d", cur_index, new_index);
3738 lv_table[j].name_cp_index = (u2)new_index;
3739 }
3740 cur_index = lv_table[j].descriptor_cp_index;
3741 new_index = find_new_index(cur_index);
3742 if (new_index != 0) {
3743 log_trace(redefine, class, constantpool)("lvt-descriptor_cp_index change: %d to %d", cur_index, new_index);
3744 lv_table[j].descriptor_cp_index = (u2)new_index;
3745 }
3746 cur_index = lv_table[j].signature_cp_index;
3747 new_index = find_new_index(cur_index);
3748 if (new_index != 0) {
3749 log_trace(redefine, class, constantpool)("lvt-signature_cp_index change: %d to %d", cur_index, new_index);
3750 lv_table[j].signature_cp_index = (u2)new_index;
3751 }
3752 } // end for each local variable table entry
3753 } // end if there are local variable table entries
3754
3755 // Update constant pool indices in the method's method_parameters.
3756 int mp_length = method->method_parameters_length();
3757 if (mp_length > 0) {
3758 MethodParametersElement* elem = method->method_parameters_start();
3759 for (int j = 0; j < mp_length; j++) {
3760 const int cp_index = elem[j].name_cp_index;
3761 const int new_cp_index = find_new_index(cp_index);
3762 if (new_cp_index != 0) {
3763 elem[j].name_cp_index = (u2)new_cp_index;
3764 }
3765 }
3766 }
3767
3768 rewrite_cp_refs_in_stack_map_table(method);
3769 } // end for each method
3770 } // end set_new_constant_pool()
3771
3772
3773 // Unevolving classes may point to methods of the_class directly
3774 // from their constant pool caches, itables, and/or vtables. We
3775 // use the ClassLoaderDataGraph::classes_do() facility and this helper
3776 // to fix up these pointers. MethodData also points to old methods and
3777 // must be cleaned.
3778
3779 // Adjust cpools and vtables closure
3780 void VM_RedefineClasses::AdjustAndCleanMetadata::do_klass(Klass* k) {
3781
3782 // This is a very busy routine. We don't want too much tracing
3783 // printed out.
3784 bool trace_name_printed = false;
3785
3786 // If the class being redefined is java.lang.Object, we need to fix all
3787 // array class vtables also. The _has_redefined_Object flag is global.
3788 // Once the java.lang.Object has been redefined (by the current or one
3789 // of the previous VM_RedefineClasses operations) we have to always
3790 // adjust method entries for array classes.
3791 if (k->is_array_klass() && _has_redefined_Object) {
3792 k->vtable().adjust_method_entries(&trace_name_printed);
3793
3794 } else if (k->is_instance_klass()) {
3795 HandleMark hm(_thread);
3796 InstanceKlass *ik = InstanceKlass::cast(k);
3797
3798 // Clean MethodData of this class's methods so they don't refer to
3799 // old methods that are no longer running.
3800 Array<Method*>* methods = ik->methods();
3801 int num_methods = methods->length();
3802 for (int index = 0; index < num_methods; ++index) {
3803 if (methods->at(index)->method_data() != nullptr) {
3804 methods->at(index)->method_data()->clean_weak_method_links();
3805 }
3806 }
3807
3808 // Adjust all vtables, default methods and itables, to clean out old methods.
3809 ResourceMark rm(_thread);
3810 if (ik->vtable_length() > 0) {
3811 ik->vtable().adjust_method_entries(&trace_name_printed);
3812 ik->adjust_default_methods(&trace_name_printed);
3813 }
3814
3815 if (ik->itable_length() > 0) {
3816 ik->itable().adjust_method_entries(&trace_name_printed);
3817 }
3818
3819 // The constant pools in other classes (other_cp) can refer to
3820 // old methods. We have to update method information in
3821 // other_cp's cache. If other_cp has a previous version, then we
3822 // have to repeat the process for each previous version. The
3823 // constant pool cache holds the Method*s for non-virtual
3824 // methods and for virtual, final methods.
3825 //
3826 // Special case: if the current class is being redefined by the current
3827 // VM_RedefineClasses operation, then new_cp has already been attached
3828 // to the_class and old_cp has already been added as a previous version.
3829 // The new_cp doesn't have any cached references to old methods so it
3830 // doesn't need to be updated and we could optimize by skipping it.
3831 // However, the current class can be marked as being redefined by another
3832 // VM_RedefineClasses operation which has already executed its doit_prologue
3833 // and needs cpcache method entries adjusted. For simplicity, the cpcache
3834 // update is done unconditionally. It should result in doing nothing for
3835 // classes being redefined by the current VM_RedefineClasses operation.
3836 // Method entries in the previous version(s) are adjusted as well.
3837 ConstantPoolCache* cp_cache;
3838
3839 // this klass' constant pool cache may need adjustment
3840 ConstantPool* other_cp = ik->constants();
3841 cp_cache = other_cp->cache();
3842 if (cp_cache != nullptr) {
3843 cp_cache->adjust_method_entries(&trace_name_printed);
3844 }
3845
3846 // the previous versions' constant pool caches may need adjustment
3847 for (InstanceKlass* pv_node = ik->previous_versions();
3848 pv_node != nullptr;
3849 pv_node = pv_node->previous_versions()) {
3850 cp_cache = pv_node->constants()->cache();
3851 if (cp_cache != nullptr) {
3852 cp_cache->adjust_method_entries(&trace_name_printed);
3853 }
3854 }
3855 }
3856 }
3857
3858 void VM_RedefineClasses::update_jmethod_ids() {
3859 for (int j = 0; j < _matching_methods_length; ++j) {
3860 Method* old_method = _matching_old_methods[j];
3861 jmethodID jmid = old_method->find_jmethod_id_or_null();
3862 if (jmid != nullptr) {
3863 // There is a jmethodID, change it to point to the new method
3864 Method* new_method = _matching_new_methods[j];
3865 Method::change_method_associated_with_jmethod_id(jmid, new_method);
3866 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j],
3867 "should be replaced");
3868 }
3869 }
3870 }
3871
3872 int VM_RedefineClasses::check_methods_and_mark_as_obsolete() {
3873 int emcp_method_count = 0;
3874 int obsolete_count = 0;
3875 int old_index = 0;
3876 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
3877 Method* old_method = _matching_old_methods[j];
3878 Method* new_method = _matching_new_methods[j];
3879 Method* old_array_method;
3880
3881 // Maintain an old_index into the _old_methods array by skipping
3882 // deleted methods
3883 while ((old_array_method = _old_methods->at(old_index)) != old_method) {
3884 ++old_index;
3885 }
3886
3887 if (MethodComparator::methods_EMCP(old_method, new_method)) {
3888 // The EMCP definition from JSR-163 requires the bytecodes to be
3889 // the same with the exception of constant pool indices which may
3890 // differ. However, the constants referred to by those indices
3891 // must be the same.
3892 //
3893 // We use methods_EMCP() for comparison since constant pool
3894 // merging can remove duplicate constant pool entries that were
3895 // present in the old method and removed from the rewritten new
3896 // method. A faster binary comparison function would consider the
3897 // old and new methods to be different when they are actually
3898 // EMCP.
3899 //
3900 // The old and new methods are EMCP and you would think that we
3901 // could get rid of one of them here and now and save some space.
3902 // However, the concept of EMCP only considers the bytecodes and
3903 // the constant pool entries in the comparison. Other things,
3904 // e.g., the line number table (LNT) or the local variable table
3905 // (LVT) don't count in the comparison. So the new (and EMCP)
3906 // method can have a new LNT that we need so we can't just
3907 // overwrite the new method with the old method.
3908 //
3909 // When this routine is called, we have already attached the new
3910 // methods to the_class so the old methods are effectively
3911 // overwritten. However, if an old method is still executing,
3912 // then the old method cannot be collected until sometime after
3913 // the old method call has returned. So the overwriting of old
3914 // methods by new methods will save us space except for those
3915 // (hopefully few) old methods that are still executing.
3916 //
3917 // A method refers to a ConstMethod* and this presents another
3918 // possible avenue to space savings. The ConstMethod* in the
3919 // new method contains possibly new attributes (LNT, LVT, etc).
3920 // At first glance, it seems possible to save space by replacing
3921 // the ConstMethod* in the old method with the ConstMethod*
3922 // from the new method. The old and new methods would share the
3923 // same ConstMethod* and we would save the space occupied by
3924 // the old ConstMethod*. However, the ConstMethod* contains
3925 // a back reference to the containing method. Sharing the
3926 // ConstMethod* between two methods could lead to confusion in
3927 // the code that uses the back reference. This would lead to
3928 // brittle code that could be broken in non-obvious ways now or
3929 // in the future.
3930 //
3931 // Another possibility is to copy the ConstMethod* from the new
3932 // method to the old method and then overwrite the new method with
3933 // the old method. Since the ConstMethod* contains the bytecodes
3934 // for the method embedded in the oop, this option would change
3935 // the bytecodes out from under any threads executing the old
3936 // method and make the thread's bcp invalid. Since EMCP requires
3937 // that the bytecodes be the same modulo constant pool indices, it
3938 // is straight forward to compute the correct new bcp in the new
3939 // ConstMethod* from the old bcp in the old ConstMethod*. The
3940 // time consuming part would be searching all the frames in all
3941 // of the threads to find all of the calls to the old method.
3942 //
3943 // It looks like we will have to live with the limited savings
3944 // that we get from effectively overwriting the old methods
3945 // when the new methods are attached to the_class.
3946
3947 // Count number of methods that are EMCP. The method will be marked
3948 // old but not obsolete if it is EMCP.
3949 emcp_method_count++;
3950
3951 // An EMCP method is _not_ obsolete. An obsolete method has a
3952 // different jmethodID than the current method. An EMCP method
3953 // has the same jmethodID as the current method. Having the
3954 // same jmethodID for all EMCP versions of a method allows for
3955 // a consistent view of the EMCP methods regardless of which
3956 // EMCP method you happen to have in hand. For example, a
3957 // breakpoint set in one EMCP method will work for all EMCP
3958 // versions of the method including the current one.
3959 } else {
3960 // mark obsolete methods as such
3961 old_method->set_is_obsolete();
3962 obsolete_count++;
3963
3964 // obsolete methods need a unique idnum so they become new entries in
3965 // the jmethodID cache in InstanceKlass
3966 assert(old_method->method_idnum() == new_method->method_idnum(), "must match");
3967 u2 num = InstanceKlass::cast(_the_class)->next_method_idnum();
3968 if (num != ConstMethod::UNSET_IDNUM) {
3969 old_method->set_method_idnum(num);
3970 }
3971
3972 // With tracing we try not to "yack" too much. The position of
3973 // this trace assumes there are fewer obsolete methods than
3974 // EMCP methods.
3975 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) {
3976 ResourceMark rm;
3977 log_trace(redefine, class, obsolete, mark)
3978 ("mark %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string());
3979 }
3980 }
3981 old_method->set_is_old();
3982 }
3983 for (int i = 0; i < _deleted_methods_length; ++i) {
3984 Method* old_method = _deleted_methods[i];
3985
3986 assert(!old_method->has_vtable_index(),
3987 "cannot delete methods with vtable entries");;
3988
3989 // Mark all deleted methods as old, obsolete and deleted
3990 old_method->set_is_deleted();
3991 old_method->set_is_old();
3992 old_method->set_is_obsolete();
3993 ++obsolete_count;
3994 // With tracing we try not to "yack" too much. The position of
3995 // this trace assumes there are fewer obsolete methods than
3996 // EMCP methods.
3997 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) {
3998 ResourceMark rm;
3999 log_trace(redefine, class, obsolete, mark)
4000 ("mark deleted %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string());
4001 }
4002 }
4003 assert((emcp_method_count + obsolete_count) == _old_methods->length(),
4004 "sanity check");
4005 log_trace(redefine, class, obsolete, mark)("EMCP_cnt=%d, obsolete_cnt=%d", emcp_method_count, obsolete_count);
4006 return emcp_method_count;
4007 }
4008
4009 // This internal class transfers the native function registration from old methods
4010 // to new methods. It is designed to handle both the simple case of unchanged
4011 // native methods and the complex cases of native method prefixes being added and/or
4012 // removed.
4013 // It expects only to be used during the VM_RedefineClasses op (a safepoint).
4014 //
4015 // This class is used after the new methods have been installed in "the_class".
4016 //
4017 // So, for example, the following must be handled. Where 'm' is a method and
4018 // a number followed by an underscore is a prefix.
4019 //
4020 // Old Name New Name
4021 // Simple transfer to new method m -> m
4022 // Add prefix m -> 1_m
4023 // Remove prefix 1_m -> m
4024 // Simultaneous add of prefixes m -> 3_2_1_m
4025 // Simultaneous removal of prefixes 3_2_1_m -> m
4026 // Simultaneous add and remove 1_m -> 2_m
4027 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m
4028 //
4029 class TransferNativeFunctionRegistration {
4030 private:
4031 InstanceKlass* the_class;
4032 int prefix_count;
4033 char** prefixes;
4034
4035 // Recursively search the binary tree of possibly prefixed method names.
4036 // Iteration could be used if all agents were well behaved. Full tree walk is
4037 // more resilent to agents not cleaning up intermediate methods.
4038 // Branch at each depth in the binary tree is:
4039 // (1) without the prefix.
4040 // (2) with the prefix.
4041 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
4042 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len,
4043 Symbol* signature) {
4044 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len);
4045 if (name_symbol != nullptr) {
4046 Method* method = the_class->lookup_method(name_symbol, signature);
4047 if (method != nullptr) {
4048 // Even if prefixed, intermediate methods must exist.
4049 if (method->is_native()) {
4050 // Wahoo, we found a (possibly prefixed) version of the method, return it.
4051 return method;
4052 }
4053 if (depth < prefix_count) {
4054 // Try applying further prefixes (other than this one).
4055 method = search_prefix_name_space(depth+1, name_str, name_len, signature);
4056 if (method != nullptr) {
4057 return method; // found
4058 }
4059
4060 // Try adding this prefix to the method name and see if it matches
4061 // another method name.
4062 char* prefix = prefixes[depth];
4063 size_t prefix_len = strlen(prefix);
4064 size_t trial_len = name_len + prefix_len;
4065 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
4066 strcpy(trial_name_str, prefix);
4067 strcat(trial_name_str, name_str);
4068 method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
4069 signature);
4070 if (method != nullptr) {
4071 // If found along this branch, it was prefixed, mark as such
4072 method->set_is_prefixed_native();
4073 return method; // found
4074 }
4075 }
4076 }
4077 }
4078 return nullptr; // This whole branch bore nothing
4079 }
4080
4081 // Return the method name with old prefixes stripped away.
4082 char* method_name_without_prefixes(Method* method) {
4083 Symbol* name = method->name();
4084 char* name_str = name->as_utf8();
4085
4086 // Old prefixing may be defunct, strip prefixes, if any.
4087 for (int i = prefix_count-1; i >= 0; i--) {
4088 char* prefix = prefixes[i];
4089 size_t prefix_len = strlen(prefix);
4090 if (strncmp(prefix, name_str, prefix_len) == 0) {
4091 name_str += prefix_len;
4092 }
4093 }
4094 return name_str;
4095 }
4096
4097 // Strip any prefixes off the old native method, then try to find a
4098 // (possibly prefixed) new native that matches it.
4099 Method* strip_and_search_for_new_native(Method* method) {
4100 ResourceMark rm;
4101 char* name_str = method_name_without_prefixes(method);
4102 return search_prefix_name_space(0, name_str, strlen(name_str),
4103 method->signature());
4104 }
4105
4106 public:
4107
4108 // Construct a native method transfer processor for this class.
4109 TransferNativeFunctionRegistration(InstanceKlass* _the_class) {
4110 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
4111
4112 the_class = _the_class;
4113 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
4114 }
4115
4116 // Attempt to transfer any of the old or deleted methods that are native
4117 void transfer_registrations(Method** old_methods, int methods_length) {
4118 for (int j = 0; j < methods_length; j++) {
4119 Method* old_method = old_methods[j];
4120
4121 if (old_method->is_native() && old_method->has_native_function()) {
4122 Method* new_method = strip_and_search_for_new_native(old_method);
4123 if (new_method != nullptr) {
4124 // Actually set the native function in the new method.
4125 // Redefine does not send events (except CFLH), certainly not this
4126 // behind the scenes re-registration.
4127 new_method->set_native_function(old_method->native_function(),
4128 !Method::native_bind_event_is_interesting);
4129 }
4130 }
4131 }
4132 }
4133 };
4134
4135 // Don't lose the association between a native method and its JNI function.
4136 void VM_RedefineClasses::transfer_old_native_function_registrations(InstanceKlass* the_class) {
4137 TransferNativeFunctionRegistration transfer(the_class);
4138 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length);
4139 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length);
4140 }
4141
4142 // Deoptimize all compiled code that depends on the classes redefined.
4143 //
4144 // If the can_redefine_classes capability is obtained in the onload
4145 // phase then the compiler has recorded all dependencies from startup.
4146 // In that case we need only deoptimize and throw away all compiled code
4147 // that depends on the class.
4148 //
4149 // If can_redefine_classes is obtained sometime after the onload
4150 // phase then the dependency information may be incomplete. In that case
4151 // the first call to RedefineClasses causes all compiled code to be
4152 // thrown away. As can_redefine_classes has been obtained then
4153 // all future compilations will record dependencies so second and
4154 // subsequent calls to RedefineClasses need only throw away code
4155 // that depends on the class.
4156 //
4157
4158 void VM_RedefineClasses::flush_dependent_code() {
4159 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
4160
4161 DeoptimizationScope deopt_scope;
4162
4163 // This is the first redefinition, mark all the nmethods for deoptimization
4164 if (!JvmtiExport::all_dependencies_are_recorded()) {
4165 CodeCache::mark_all_nmethods_for_evol_deoptimization(&deopt_scope);
4166 log_debug(redefine, class, nmethod)("Marked all nmethods for deopt");
4167 } else {
4168 CodeCache::mark_dependents_for_evol_deoptimization(&deopt_scope);
4169 log_debug(redefine, class, nmethod)("Marked dependent nmethods for deopt");
4170 }
4171
4172 deopt_scope.deoptimize_marked();
4173
4174 // From now on we know that the dependency information is complete
4175 JvmtiExport::set_all_dependencies_are_recorded(true);
4176 }
4177
4178 void VM_RedefineClasses::compute_added_deleted_matching_methods() {
4179 Method* old_method;
4180 Method* new_method;
4181
4182 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
4183 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
4184 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length());
4185 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
4186
4187 _matching_methods_length = 0;
4188 _deleted_methods_length = 0;
4189 _added_methods_length = 0;
4190
4191 int nj = 0;
4192 int oj = 0;
4193 while (true) {
4194 if (oj >= _old_methods->length()) {
4195 if (nj >= _new_methods->length()) {
4196 break; // we've looked at everything, done
4197 }
4198 // New method at the end
4199 new_method = _new_methods->at(nj);
4200 _added_methods[_added_methods_length++] = new_method;
4201 ++nj;
4202 } else if (nj >= _new_methods->length()) {
4203 // Old method, at the end, is deleted
4204 old_method = _old_methods->at(oj);
4205 _deleted_methods[_deleted_methods_length++] = old_method;
4206 ++oj;
4207 } else {
4208 old_method = _old_methods->at(oj);
4209 new_method = _new_methods->at(nj);
4210 if (old_method->name() == new_method->name()) {
4211 if (old_method->signature() == new_method->signature()) {
4212 _matching_old_methods[_matching_methods_length ] = old_method;
4213 _matching_new_methods[_matching_methods_length++] = new_method;
4214 ++nj;
4215 ++oj;
4216 } else {
4217 // added overloaded have already been moved to the end,
4218 // so this is a deleted overloaded method
4219 _deleted_methods[_deleted_methods_length++] = old_method;
4220 ++oj;
4221 }
4222 } else { // names don't match
4223 if (old_method->name()->fast_compare(new_method->name()) > 0) {
4224 // new method
4225 _added_methods[_added_methods_length++] = new_method;
4226 ++nj;
4227 } else {
4228 // deleted method
4229 _deleted_methods[_deleted_methods_length++] = old_method;
4230 ++oj;
4231 }
4232 }
4233 }
4234 }
4235 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
4236 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
4237 }
4238
4239
4240 void VM_RedefineClasses::swap_annotations(InstanceKlass* the_class,
4241 InstanceKlass* scratch_class) {
4242 // Swap annotation fields values
4243 Annotations* old_annotations = the_class->annotations();
4244 the_class->set_annotations(scratch_class->annotations());
4245 scratch_class->set_annotations(old_annotations);
4246 }
4247
4248
4249 // Install the redefinition of a class:
4250 // - house keeping (flushing breakpoints and caches, deoptimizing
4251 // dependent compiled code)
4252 // - replacing parts in the_class with parts from scratch_class
4253 // - adding a weak reference to track the obsolete but interesting
4254 // parts of the_class
4255 // - adjusting constant pool caches and vtables in other classes
4256 // that refer to methods in the_class. These adjustments use the
4257 // ClassLoaderDataGraph::classes_do() facility which only allows
4258 // a helper method to be specified. The interesting parameters
4259 // that we would like to pass to the helper method are saved in
4260 // static global fields in the VM operation.
4261 void VM_RedefineClasses::redefine_single_class(Thread* current, jclass the_jclass,
4262 InstanceKlass* scratch_class) {
4263
4264 HandleMark hm(current); // make sure handles from this call are freed
4265
4266 if (log_is_enabled(Info, redefine, class, timer)) {
4267 _timer_rsc_phase1.start();
4268 }
4269
4270 InstanceKlass* the_class = get_ik(the_jclass);
4271
4272 // Set a flag to control and optimize adjusting method entries
4273 _has_redefined_Object |= the_class == vmClasses::Object_klass();
4274
4275 // Remove all breakpoints in methods of this class
4276 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
4277 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class);
4278
4279 _old_methods = the_class->methods();
4280 _new_methods = scratch_class->methods();
4281 _the_class = the_class;
4282 compute_added_deleted_matching_methods();
4283 update_jmethod_ids();
4284
4285 _any_class_has_resolved_methods = the_class->has_resolved_methods() || _any_class_has_resolved_methods;
4286
4287 // Attach new constant pool to the original klass. The original
4288 // klass still refers to the old constant pool (for now).
4289 scratch_class->constants()->set_pool_holder(the_class);
4290
4291 #if 0
4292 // In theory, with constant pool merging in place we should be able
4293 // to save space by using the new, merged constant pool in place of
4294 // the old constant pool(s). By "pool(s)" I mean the constant pool in
4295 // the klass version we are replacing now and any constant pool(s) in
4296 // previous versions of klass. Nice theory, doesn't work in practice.
4297 // When this code is enabled, even simple programs throw NullPointer
4298 // exceptions. I'm guessing that this is caused by some constant pool
4299 // cache difference between the new, merged constant pool and the
4300 // constant pool that was just being used by the klass. I'm keeping
4301 // this code around to archive the idea, but the code has to remain
4302 // disabled for now.
4303
4304 // Attach each old method to the new constant pool. This can be
4305 // done here since we are past the bytecode verification and
4306 // constant pool optimization phases.
4307 for (int i = _old_methods->length() - 1; i >= 0; i--) {
4308 Method* method = _old_methods->at(i);
4309 method->set_constants(scratch_class->constants());
4310 }
4311
4312 // NOTE: this doesn't work because you can redefine the same class in two
4313 // threads, each getting their own constant pool data appended to the
4314 // original constant pool. In order for the new methods to work when they
4315 // become old methods, they need to keep their updated copy of the constant pool.
4316
4317 {
4318 // walk all previous versions of the klass
4319 InstanceKlass *ik = the_class;
4320 PreviousVersionWalker pvw(ik);
4321 do {
4322 ik = pvw.next_previous_version();
4323 if (ik != nullptr) {
4324
4325 // attach previous version of klass to the new constant pool
4326 ik->set_constants(scratch_class->constants());
4327
4328 // Attach each method in the previous version of klass to the
4329 // new constant pool
4330 Array<Method*>* prev_methods = ik->methods();
4331 for (int i = prev_methods->length() - 1; i >= 0; i--) {
4332 Method* method = prev_methods->at(i);
4333 method->set_constants(scratch_class->constants());
4334 }
4335 }
4336 } while (ik != nullptr);
4337 }
4338 #endif
4339
4340 // Replace methods and constantpool
4341 the_class->set_methods(_new_methods);
4342 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods,
4343 // and to be able to undo operation easily.
4344
4345 Array<int>* old_ordering = the_class->method_ordering();
4346 the_class->set_method_ordering(scratch_class->method_ordering());
4347 scratch_class->set_method_ordering(old_ordering);
4348
4349 ConstantPool* old_constants = the_class->constants();
4350 the_class->set_constants(scratch_class->constants());
4351 scratch_class->set_constants(old_constants); // See the previous comment.
4352 #if 0
4353 // We are swapping the guts of "the new class" with the guts of "the
4354 // class". Since the old constant pool has just been attached to "the
4355 // new class", it seems logical to set the pool holder in the old
4356 // constant pool also. However, doing this will change the observable
4357 // class hierarchy for any old methods that are still executing. A
4358 // method can query the identity of its "holder" and this query uses
4359 // the method's constant pool link to find the holder. The change in
4360 // holding class from "the class" to "the new class" can confuse
4361 // things.
4362 //
4363 // Setting the old constant pool's holder will also cause
4364 // verification done during vtable initialization below to fail.
4365 // During vtable initialization, the vtable's class is verified to be
4366 // a subtype of the method's holder. The vtable's class is "the
4367 // class" and the method's holder is gotten from the constant pool
4368 // link in the method itself. For "the class"'s directly implemented
4369 // methods, the method holder is "the class" itself (as gotten from
4370 // the new constant pool). The check works fine in this case. The
4371 // check also works fine for methods inherited from super classes.
4372 //
4373 // Miranda methods are a little more complicated. A miranda method is
4374 // provided by an interface when the class implementing the interface
4375 // does not provide its own method. These interfaces are implemented
4376 // internally as an InstanceKlass. These special instanceKlasses
4377 // share the constant pool of the class that "implements" the
4378 // interface. By sharing the constant pool, the method holder of a
4379 // miranda method is the class that "implements" the interface. In a
4380 // non-redefine situation, the subtype check works fine. However, if
4381 // the old constant pool's pool holder is modified, then the check
4382 // fails because there is no class hierarchy relationship between the
4383 // vtable's class and "the new class".
4384
4385 old_constants->set_pool_holder(scratch_class());
4386 #endif
4387
4388 // track number of methods that are EMCP for add_previous_version() call below
4389 int emcp_method_count = check_methods_and_mark_as_obsolete();
4390 transfer_old_native_function_registrations(the_class);
4391
4392 if (scratch_class->get_cached_class_file() != the_class->get_cached_class_file()) {
4393 // 1. the_class doesn't have a cache yet, scratch_class does have a cache.
4394 // 2. The same class can be present twice in the scratch classes list or there
4395 // are multiple concurrent RetransformClasses calls on different threads.
4396 // the_class and scratch_class have the same cached bytes, but different buffers.
4397 // In such cases we need to deallocate one of the buffers.
4398 // 3. RedefineClasses and the_class has cached bytes from a previous transformation.
4399 // In the case we need to use class bytes from scratch_class.
4400 if (the_class->get_cached_class_file() != nullptr) {
4401 os::free(the_class->get_cached_class_file());
4402 }
4403 the_class->set_cached_class_file(scratch_class->get_cached_class_file());
4404 }
4405
4406 // null out in scratch class to not delete twice. The class to be redefined
4407 // always owns these bytes.
4408 scratch_class->set_cached_class_file(nullptr);
4409
4410 // Replace inner_classes
4411 Array<u2>* old_inner_classes = the_class->inner_classes();
4412 the_class->set_inner_classes(scratch_class->inner_classes());
4413 scratch_class->set_inner_classes(old_inner_classes);
4414
4415 // Initialize the vtable and interface table after
4416 // methods have been rewritten
4417 // no exception should happen here since we explicitly
4418 // do not check loader constraints.
4419 // compare_and_normalize_class_versions has already checked:
4420 // - classloaders unchanged, signatures unchanged
4421 // - all instanceKlasses for redefined classes reused & contents updated
4422 the_class->vtable().initialize_vtable();
4423 the_class->itable().initialize_itable();
4424
4425 // Leave arrays of jmethodIDs and itable index cache unchanged
4426
4427 // Copy the "source debug extension" attribute from new class version
4428 the_class->set_source_debug_extension(
4429 scratch_class->source_debug_extension(),
4430 scratch_class->source_debug_extension() == nullptr ? 0 :
4431 (int)strlen(scratch_class->source_debug_extension()));
4432
4433 // Use of javac -g could be different in the old and the new
4434 if (scratch_class->has_localvariable_table() !=
4435 the_class->has_localvariable_table()) {
4436 the_class->set_has_localvariable_table(scratch_class->has_localvariable_table());
4437 }
4438
4439 swap_annotations(the_class, scratch_class);
4440
4441 // Replace minor version number of class file
4442 u2 old_minor_version = the_class->constants()->minor_version();
4443 the_class->constants()->set_minor_version(scratch_class->constants()->minor_version());
4444 scratch_class->constants()->set_minor_version(old_minor_version);
4445
4446 // Replace major version number of class file
4447 u2 old_major_version = the_class->constants()->major_version();
4448 the_class->constants()->set_major_version(scratch_class->constants()->major_version());
4449 scratch_class->constants()->set_major_version(old_major_version);
4450
4451 // Replace CP indexes for class and name+type of enclosing method
4452 u2 old_class_idx = the_class->enclosing_method_class_index();
4453 u2 old_method_idx = the_class->enclosing_method_method_index();
4454 the_class->set_enclosing_method_indices(
4455 scratch_class->enclosing_method_class_index(),
4456 scratch_class->enclosing_method_method_index());
4457 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx);
4458
4459 if (!the_class->has_been_redefined()) {
4460 the_class->set_has_been_redefined();
4461 }
4462
4463 // Scratch class is unloaded but still needs cleaning, and skipping for CDS.
4464 scratch_class->set_is_scratch_class();
4465
4466 // keep track of previous versions of this class
4467 the_class->add_previous_version(scratch_class, emcp_method_count);
4468
4469 _timer_rsc_phase1.stop();
4470 if (log_is_enabled(Info, redefine, class, timer)) {
4471 _timer_rsc_phase2.start();
4472 }
4473
4474 if (the_class->oop_map_cache() != nullptr) {
4475 // Flush references to any obsolete methods from the oop map cache
4476 // so that obsolete methods are not pinned.
4477 the_class->oop_map_cache()->flush_obsolete_entries();
4478 }
4479
4480 increment_class_counter(the_class);
4481
4482 if (EventClassRedefinition::is_enabled()) {
4483 EventClassRedefinition event;
4484 event.set_classModificationCount(java_lang_Class::classRedefinedCount(the_class->java_mirror()));
4485 event.set_redefinedClass(the_class);
4486 event.set_redefinitionId(_id);
4487 event.commit();
4488 }
4489
4490 {
4491 ResourceMark rm(current);
4492 // increment the classRedefinedCount field in the_class and in any
4493 // direct and indirect subclasses of the_class
4494 log_info(redefine, class, load)
4495 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)",
4496 the_class->external_name(), java_lang_Class::classRedefinedCount(the_class->java_mirror()), os::available_memory() >> 10);
4497 Events::log_redefinition(current, "redefined class name=%s, count=%d",
4498 the_class->external_name(),
4499 java_lang_Class::classRedefinedCount(the_class->java_mirror()));
4500
4501 }
4502 _timer_rsc_phase2.stop();
4503
4504 } // end redefine_single_class()
4505
4506
4507 // Increment the classRedefinedCount field in the specific InstanceKlass
4508 // and in all direct and indirect subclasses.
4509 void VM_RedefineClasses::increment_class_counter(InstanceKlass* ik) {
4510 for (ClassHierarchyIterator iter(ik); !iter.done(); iter.next()) {
4511 // Only update instanceKlasses
4512 Klass* sub = iter.klass();
4513 if (sub->is_instance_klass()) {
4514 oop class_mirror = InstanceKlass::cast(sub)->java_mirror();
4515 Klass* class_oop = java_lang_Class::as_Klass(class_mirror);
4516 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
4517 java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
4518
4519 if (class_oop != _the_class) {
4520 // _the_class count is printed at end of redefine_single_class()
4521 log_debug(redefine, class, subclass)("updated count in subclass=%s to %d", ik->external_name(), new_count);
4522 }
4523 }
4524 }
4525 }
4526
4527 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) {
4528 bool no_old_methods = true; // be optimistic
4529
4530 // Both array and instance classes have vtables.
4531 // a vtable should never contain old or obsolete methods
4532 ResourceMark rm(_thread);
4533 if (k->vtable_length() > 0 &&
4534 !k->vtable().check_no_old_or_obsolete_entries()) {
4535 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4536 log_trace(redefine, class, obsolete, metadata)
4537 ("klassVtable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4538 k->signature_name());
4539 k->vtable().dump_vtable();
4540 }
4541 no_old_methods = false;
4542 }
4543
4544 if (k->is_instance_klass()) {
4545 HandleMark hm(_thread);
4546 InstanceKlass *ik = InstanceKlass::cast(k);
4547
4548 // an itable should never contain old or obsolete methods
4549 if (ik->itable_length() > 0 &&
4550 !ik->itable().check_no_old_or_obsolete_entries()) {
4551 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4552 log_trace(redefine, class, obsolete, metadata)
4553 ("klassItable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4554 ik->signature_name());
4555 ik->itable().dump_itable();
4556 }
4557 no_old_methods = false;
4558 }
4559
4560 // the constant pool cache should never contain non-deleted old or obsolete methods
4561 if (ik->constants() != nullptr &&
4562 ik->constants()->cache() != nullptr &&
4563 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) {
4564 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4565 log_trace(redefine, class, obsolete, metadata)
4566 ("cp-cache::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4567 ik->signature_name());
4568 ik->constants()->cache()->dump_cache();
4569 }
4570 no_old_methods = false;
4571 }
4572 }
4573
4574 // print and fail guarantee if old methods are found.
4575 if (!no_old_methods) {
4576 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4577 dump_methods();
4578 } else {
4579 log_trace(redefine, class)("Use the '-Xlog:redefine+class*:' option "
4580 "to see more info about the following guarantee() failure.");
4581 }
4582 guarantee(false, "OLD and/or OBSOLETE method(s) found");
4583 }
4584 }
4585
4586 u8 VM_RedefineClasses::next_id() {
4587 while (true) {
4588 u8 id = _id_counter;
4589 u8 next_id = id + 1;
4590 u8 result = Atomic::cmpxchg(&_id_counter, id, next_id);
4591 if (result == id) {
4592 return next_id;
4593 }
4594 }
4595 }
4596
4597 void VM_RedefineClasses::dump_methods() {
4598 int j;
4599 log_trace(redefine, class, dump)("_old_methods --");
4600 for (j = 0; j < _old_methods->length(); ++j) {
4601 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4602 Method* m = _old_methods->at(j);
4603 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4604 m->access_flags().print_on(&log_stream);
4605 log_stream.print(" -- ");
4606 m->print_name(&log_stream);
4607 log_stream.cr();
4608 }
4609 log_trace(redefine, class, dump)("_new_methods --");
4610 for (j = 0; j < _new_methods->length(); ++j) {
4611 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4612 Method* m = _new_methods->at(j);
4613 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4614 m->access_flags().print_on(&log_stream);
4615 log_stream.print(" -- ");
4616 m->print_name(&log_stream);
4617 log_stream.cr();
4618 }
4619 log_trace(redefine, class, dump)("_matching_methods --");
4620 for (j = 0; j < _matching_methods_length; ++j) {
4621 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4622 Method* m = _matching_old_methods[j];
4623 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4624 m->access_flags().print_on(&log_stream);
4625 log_stream.print(" -- ");
4626 m->print_name();
4627 log_stream.cr();
4628
4629 m = _matching_new_methods[j];
4630 log_stream.print(" (%5d) ", m->vtable_index());
4631 m->access_flags().print_on(&log_stream);
4632 log_stream.cr();
4633 }
4634 log_trace(redefine, class, dump)("_deleted_methods --");
4635 for (j = 0; j < _deleted_methods_length; ++j) {
4636 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4637 Method* m = _deleted_methods[j];
4638 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4639 m->access_flags().print_on(&log_stream);
4640 log_stream.print(" -- ");
4641 m->print_name(&log_stream);
4642 log_stream.cr();
4643 }
4644 log_trace(redefine, class, dump)("_added_methods --");
4645 for (j = 0; j < _added_methods_length; ++j) {
4646 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4647 Method* m = _added_methods[j];
4648 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4649 m->access_flags().print_on(&log_stream);
4650 log_stream.print(" -- ");
4651 m->print_name(&log_stream);
4652 log_stream.cr();
4653 }
4654 }
4655
4656 void VM_RedefineClasses::print_on_error(outputStream* st) const {
4657 VM_Operation::print_on_error(st);
4658 if (_the_class != nullptr) {
4659 ResourceMark rm;
4660 st->print_cr(", redefining class %s", _the_class->external_name());
4661 }
4662 }