1 /*
2 * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "cds/metaspaceShared.hpp"
27 #include "classfile/classFileStream.hpp"
28 #include "classfile/classLoaderDataGraph.hpp"
29 #include "classfile/classLoadInfo.hpp"
30 #include "classfile/javaClasses.inline.hpp"
31 #include "classfile/metadataOnStackMark.hpp"
32 #include "classfile/symbolTable.hpp"
33 #include "classfile/klassFactory.hpp"
34 #include "classfile/verifier.hpp"
35 #include "classfile/vmClasses.hpp"
36 #include "classfile/vmSymbols.hpp"
37 #include "code/codeCache.hpp"
38 #include "compiler/compileBroker.hpp"
39 #include "interpreter/oopMapCache.hpp"
40 #include "interpreter/rewriter.hpp"
41 #include "jfr/jfrEvents.hpp"
42 #include "logging/logStream.hpp"
43 #include "memory/metadataFactory.hpp"
44 #include "memory/resourceArea.hpp"
45 #include "memory/universe.hpp"
46 #include "oops/annotations.hpp"
47 #include "oops/constantPool.hpp"
48 #include "oops/fieldStreams.inline.hpp"
49 #include "oops/klass.inline.hpp"
50 #include "oops/klassVtable.hpp"
51 #include "oops/oop.inline.hpp"
52 #include "oops/recordComponent.hpp"
53 #include "prims/jvmtiImpl.hpp"
54 #include "prims/jvmtiRedefineClasses.hpp"
55 #include "prims/jvmtiThreadState.inline.hpp"
56 #include "prims/resolvedMethodTable.hpp"
57 #include "prims/methodComparator.hpp"
58 #include "runtime/atomic.hpp"
59 #include "runtime/deoptimization.hpp"
60 #include "runtime/handles.inline.hpp"
61 #include "runtime/jniHandles.inline.hpp"
62 #include "runtime/relocator.hpp"
63 #include "runtime/safepointVerifiers.hpp"
64 #include "utilities/bitMap.inline.hpp"
65 #include "utilities/events.hpp"
66
67 Array<Method*>* VM_RedefineClasses::_old_methods = NULL;
68 Array<Method*>* VM_RedefineClasses::_new_methods = NULL;
69 Method** VM_RedefineClasses::_matching_old_methods = NULL;
70 Method** VM_RedefineClasses::_matching_new_methods = NULL;
71 Method** VM_RedefineClasses::_deleted_methods = NULL;
72 Method** VM_RedefineClasses::_added_methods = NULL;
73 int VM_RedefineClasses::_matching_methods_length = 0;
74 int VM_RedefineClasses::_deleted_methods_length = 0;
75 int VM_RedefineClasses::_added_methods_length = 0;
76
77 // This flag is global as the constructor does not reset it:
78 bool VM_RedefineClasses::_has_redefined_Object = false;
79 u8 VM_RedefineClasses::_id_counter = 0;
80
81 VM_RedefineClasses::VM_RedefineClasses(jint class_count,
82 const jvmtiClassDefinition *class_defs,
83 JvmtiClassLoadKind class_load_kind) {
84 _class_count = class_count;
85 _class_defs = class_defs;
86 _class_load_kind = class_load_kind;
87 _any_class_has_resolved_methods = false;
88 _res = JVMTI_ERROR_NONE;
89 _the_class = NULL;
90 _id = next_id();
91 }
92
93 static inline InstanceKlass* get_ik(jclass def) {
94 oop mirror = JNIHandles::resolve_non_null(def);
95 return InstanceKlass::cast(java_lang_Class::as_Klass(mirror));
96 }
97
98 // If any of the classes are being redefined, wait
99 // Parallel constant pool merging leads to indeterminate constant pools.
100 void VM_RedefineClasses::lock_classes() {
101 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
102 GrowableArray<Klass*>* redef_classes = state->get_classes_being_redefined();
103
104 MonitorLocker ml(RedefineClasses_lock);
105
106 if (redef_classes == NULL) {
107 redef_classes = new(ResourceObj::C_HEAP, mtClass) GrowableArray<Klass*>(1, mtClass);
108 state->set_classes_being_redefined(redef_classes);
109 }
110
111 bool has_redefined;
112 do {
113 has_redefined = false;
114 // Go through classes each time until none are being redefined. Skip
115 // the ones that are being redefined by this thread currently. Class file
116 // load hook event may trigger new class redefine when we are redefining
117 // a class (after lock_classes()).
118 for (int i = 0; i < _class_count; i++) {
119 InstanceKlass* ik = get_ik(_class_defs[i].klass);
120 // Check if we are currently redefining the class in this thread already.
121 if (redef_classes->contains(ik)) {
122 assert(ik->is_being_redefined(), "sanity");
123 } else {
124 if (ik->is_being_redefined()) {
125 ml.wait();
126 has_redefined = true;
127 break; // for loop
128 }
129 }
130 }
131 } while (has_redefined);
132
133 for (int i = 0; i < _class_count; i++) {
134 InstanceKlass* ik = get_ik(_class_defs[i].klass);
135 redef_classes->push(ik); // Add to the _classes_being_redefined list
136 ik->set_is_being_redefined(true);
137 }
138 ml.notify_all();
139 }
140
141 void VM_RedefineClasses::unlock_classes() {
142 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
143 GrowableArray<Klass*>* redef_classes = state->get_classes_being_redefined();
144 assert(redef_classes != NULL, "_classes_being_redefined is not allocated");
145
146 MonitorLocker ml(RedefineClasses_lock);
147
148 for (int i = _class_count - 1; i >= 0; i--) {
149 InstanceKlass* def_ik = get_ik(_class_defs[i].klass);
150 if (redef_classes->length() > 0) {
151 // Remove the class from _classes_being_redefined list
152 Klass* k = redef_classes->pop();
153 assert(def_ik == k, "unlocking wrong class");
154 }
155 assert(def_ik->is_being_redefined(),
156 "should be being redefined to get here");
157
158 // Unlock after we finish all redefines for this class within
159 // the thread. Same class can be pushed to the list multiple
160 // times (not more than once by each recursive redefinition).
161 if (!redef_classes->contains(def_ik)) {
162 def_ik->set_is_being_redefined(false);
163 }
164 }
165 ml.notify_all();
166 }
167
168 bool VM_RedefineClasses::doit_prologue() {
169 if (_class_count == 0) {
170 _res = JVMTI_ERROR_NONE;
171 return false;
172 }
173 if (_class_defs == NULL) {
174 _res = JVMTI_ERROR_NULL_POINTER;
175 return false;
176 }
177
178 for (int i = 0; i < _class_count; i++) {
179 if (_class_defs[i].klass == NULL) {
180 _res = JVMTI_ERROR_INVALID_CLASS;
181 return false;
182 }
183 if (_class_defs[i].class_byte_count == 0) {
184 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT;
185 return false;
186 }
187 if (_class_defs[i].class_bytes == NULL) {
188 _res = JVMTI_ERROR_NULL_POINTER;
189 return false;
190 }
191
192 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass);
193 // classes for primitives, arrays, and hidden classes
194 // cannot be redefined.
195 if (!is_modifiable_class(mirror)) {
196 _res = JVMTI_ERROR_UNMODIFIABLE_CLASS;
197 return false;
198 }
199 }
200
201 // Start timer after all the sanity checks; not quite accurate, but
202 // better than adding a bunch of stop() calls.
203 if (log_is_enabled(Info, redefine, class, timer)) {
204 _timer_vm_op_prologue.start();
205 }
206
207 lock_classes();
208 // We first load new class versions in the prologue, because somewhere down the
209 // call chain it is required that the current thread is a Java thread.
210 _res = load_new_class_versions();
211 if (_res != JVMTI_ERROR_NONE) {
212 // free any successfully created classes, since none are redefined
213 for (int i = 0; i < _class_count; i++) {
214 if (_scratch_classes[i] != NULL) {
215 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data();
216 // Free the memory for this class at class unloading time. Not before
217 // because CMS might think this is still live.
218 InstanceKlass* ik = get_ik(_class_defs[i].klass);
219 if (ik->get_cached_class_file() == _scratch_classes[i]->get_cached_class_file()) {
220 // Don't double-free cached_class_file copied from the original class if error.
221 _scratch_classes[i]->set_cached_class_file(NULL);
222 }
223 cld->add_to_deallocate_list(InstanceKlass::cast(_scratch_classes[i]));
224 }
225 }
226 // Free os::malloc allocated memory in load_new_class_version.
227 os::free(_scratch_classes);
228 _timer_vm_op_prologue.stop();
229 unlock_classes();
230 return false;
231 }
232
233 _timer_vm_op_prologue.stop();
234 return true;
235 }
236
237 void VM_RedefineClasses::doit() {
238 Thread* current = Thread::current();
239
240 #if INCLUDE_CDS
241 if (UseSharedSpaces) {
242 // Sharing is enabled so we remap the shared readonly space to
243 // shared readwrite, private just in case we need to redefine
244 // a shared class. We do the remap during the doit() phase of
245 // the safepoint to be safer.
246 if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) {
247 log_info(redefine, class, load)("failed to remap shared readonly space to readwrite, private");
248 _res = JVMTI_ERROR_INTERNAL;
249 return;
250 }
251 }
252 #endif
253
254 // Mark methods seen on stack and everywhere else so old methods are not
255 // cleaned up if they're on the stack.
256 MetadataOnStackMark md_on_stack(/*walk_all_metadata*/true, /*redefinition_walk*/true);
257 HandleMark hm(current); // make sure any handles created are deleted
258 // before the stack walk again.
259
260 for (int i = 0; i < _class_count; i++) {
261 redefine_single_class(current, _class_defs[i].klass, _scratch_classes[i]);
262 }
263
264 // Flush all compiled code that depends on the classes redefined.
265 flush_dependent_code();
266
267 // Adjust constantpool caches and vtables for all classes
268 // that reference methods of the evolved classes.
269 // Have to do this after all classes are redefined and all methods that
270 // are redefined are marked as old.
271 AdjustAndCleanMetadata adjust_and_clean_metadata(current);
272 ClassLoaderDataGraph::classes_do(&adjust_and_clean_metadata);
273
274 // JSR-292 support
275 if (_any_class_has_resolved_methods) {
276 bool trace_name_printed = false;
277 ResolvedMethodTable::adjust_method_entries(&trace_name_printed);
278 }
279
280 // Increment flag indicating that some invariants are no longer true.
281 // See jvmtiExport.hpp for detailed explanation.
282 JvmtiExport::increment_redefinition_count();
283
284 // check_class() is optionally called for product bits, but is
285 // always called for non-product bits.
286 #ifdef PRODUCT
287 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
288 #endif
289 log_trace(redefine, class, obsolete, metadata)("calling check_class");
290 CheckClass check_class(current);
291 ClassLoaderDataGraph::classes_do(&check_class);
292 #ifdef PRODUCT
293 }
294 #endif
295
296 // Clean up any metadata now unreferenced while MetadataOnStackMark is set.
297 ClassLoaderDataGraph::clean_deallocate_lists(false);
298 }
299
300 void VM_RedefineClasses::doit_epilogue() {
301 unlock_classes();
302
303 // Free os::malloc allocated memory.
304 os::free(_scratch_classes);
305
306 // Reset the_class to null for error printing.
307 _the_class = NULL;
308
309 if (log_is_enabled(Info, redefine, class, timer)) {
310 // Used to have separate timers for "doit" and "all", but the timer
311 // overhead skewed the measurements.
312 julong doit_time = _timer_rsc_phase1.milliseconds() +
313 _timer_rsc_phase2.milliseconds();
314 julong all_time = _timer_vm_op_prologue.milliseconds() + doit_time;
315
316 log_info(redefine, class, timer)
317 ("vm_op: all=" JULONG_FORMAT " prologue=" JULONG_FORMAT " doit=" JULONG_FORMAT,
318 all_time, (julong)_timer_vm_op_prologue.milliseconds(), doit_time);
319 log_info(redefine, class, timer)
320 ("redefine_single_class: phase1=" JULONG_FORMAT " phase2=" JULONG_FORMAT,
321 (julong)_timer_rsc_phase1.milliseconds(), (julong)_timer_rsc_phase2.milliseconds());
322 }
323 }
324
325 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) {
326 // classes for primitives cannot be redefined
327 if (java_lang_Class::is_primitive(klass_mirror)) {
328 return false;
329 }
330 Klass* k = java_lang_Class::as_Klass(klass_mirror);
331 // classes for arrays cannot be redefined
332 if (k == NULL || !k->is_instance_klass()) {
333 return false;
334 }
335
336 // Cannot redefine or retransform a hidden class.
337 if (InstanceKlass::cast(k)->is_hidden()) {
338 return false;
339 }
340 return true;
341 }
342
343 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p
344 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For
345 // direct CP entries, there is just the current entry to append. For
346 // indirect and double-indirect CP entries, there are zero or more
347 // referenced CP entries along with the current entry to append.
348 // Indirect and double-indirect CP entries are handled by recursive
349 // calls to append_entry() as needed. The referenced CP entries are
350 // always appended to *merge_cp_p before the referee CP entry. These
351 // referenced CP entries may already exist in *merge_cp_p in which case
352 // there is nothing extra to append and only the current entry is
353 // appended.
354 void VM_RedefineClasses::append_entry(const constantPoolHandle& scratch_cp,
355 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) {
356
357 // append is different depending on entry tag type
358 switch (scratch_cp->tag_at(scratch_i).value()) {
359
360 // The old verifier is implemented outside the VM. It loads classes,
361 // but does not resolve constant pool entries directly so we never
362 // see Class entries here with the old verifier. Similarly the old
363 // verifier does not like Class entries in the input constant pool.
364 // The split-verifier is implemented in the VM so it can optionally
365 // and directly resolve constant pool entries to load classes. The
366 // split-verifier can accept either Class entries or UnresolvedClass
367 // entries in the input constant pool. We revert the appended copy
368 // back to UnresolvedClass so that either verifier will be happy
369 // with the constant pool entry.
370 //
371 // this is an indirect CP entry so it needs special handling
372 case JVM_CONSTANT_Class:
373 case JVM_CONSTANT_UnresolvedClass:
374 {
375 int name_i = scratch_cp->klass_name_index_at(scratch_i);
376 int new_name_i = find_or_append_indirect_entry(scratch_cp, name_i, merge_cp_p,
377 merge_cp_length_p);
378
379 if (new_name_i != name_i) {
380 log_trace(redefine, class, constantpool)
381 ("Class entry@%d name_index change: %d to %d",
382 *merge_cp_length_p, name_i, new_name_i);
383 }
384
385 (*merge_cp_p)->temp_unresolved_klass_at_put(*merge_cp_length_p, new_name_i);
386 if (scratch_i != *merge_cp_length_p) {
387 // The new entry in *merge_cp_p is at a different index than
388 // the new entry in scratch_cp so we need to map the index values.
389 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
390 }
391 (*merge_cp_length_p)++;
392 } break;
393
394 // these are direct CP entries so they can be directly appended,
395 // but double and long take two constant pool entries
396 case JVM_CONSTANT_Double: // fall through
397 case JVM_CONSTANT_Long:
398 {
399 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p);
400
401 if (scratch_i != *merge_cp_length_p) {
402 // The new entry in *merge_cp_p is at a different index than
403 // the new entry in scratch_cp so we need to map the index values.
404 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
405 }
406 (*merge_cp_length_p) += 2;
407 } break;
408
409 // these are direct CP entries so they can be directly appended
410 case JVM_CONSTANT_Float: // fall through
411 case JVM_CONSTANT_Integer: // fall through
412 case JVM_CONSTANT_Utf8: // fall through
413
414 // This was an indirect CP entry, but it has been changed into
415 // Symbol*s so this entry can be directly appended.
416 case JVM_CONSTANT_String: // fall through
417 {
418 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p);
419
420 if (scratch_i != *merge_cp_length_p) {
421 // The new entry in *merge_cp_p is at a different index than
422 // the new entry in scratch_cp so we need to map the index values.
423 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
424 }
425 (*merge_cp_length_p)++;
426 } break;
427
428 // this is an indirect CP entry so it needs special handling
429 case JVM_CONSTANT_NameAndType:
430 {
431 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i);
432 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p,
433 merge_cp_length_p);
434
435 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i);
436 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i,
437 merge_cp_p, merge_cp_length_p);
438
439 // If the referenced entries already exist in *merge_cp_p, then
440 // both new_name_ref_i and new_signature_ref_i will both be 0.
441 // In that case, all we are appending is the current entry.
442 if (new_name_ref_i != name_ref_i) {
443 log_trace(redefine, class, constantpool)
444 ("NameAndType entry@%d name_ref_index change: %d to %d",
445 *merge_cp_length_p, name_ref_i, new_name_ref_i);
446 }
447 if (new_signature_ref_i != signature_ref_i) {
448 log_trace(redefine, class, constantpool)
449 ("NameAndType entry@%d signature_ref_index change: %d to %d",
450 *merge_cp_length_p, signature_ref_i, new_signature_ref_i);
451 }
452
453 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p,
454 new_name_ref_i, new_signature_ref_i);
455 if (scratch_i != *merge_cp_length_p) {
456 // The new entry in *merge_cp_p is at a different index than
457 // the new entry in scratch_cp so we need to map the index values.
458 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
459 }
460 (*merge_cp_length_p)++;
461 } break;
462
463 // this is a double-indirect CP entry so it needs special handling
464 case JVM_CONSTANT_Fieldref: // fall through
465 case JVM_CONSTANT_InterfaceMethodref: // fall through
466 case JVM_CONSTANT_Methodref:
467 {
468 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i);
469 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i,
470 merge_cp_p, merge_cp_length_p);
471
472 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i);
473 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i,
474 merge_cp_p, merge_cp_length_p);
475
476 const char *entry_name = NULL;
477 switch (scratch_cp->tag_at(scratch_i).value()) {
478 case JVM_CONSTANT_Fieldref:
479 entry_name = "Fieldref";
480 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i,
481 new_name_and_type_ref_i);
482 break;
483 case JVM_CONSTANT_InterfaceMethodref:
484 entry_name = "IFMethodref";
485 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p,
486 new_klass_ref_i, new_name_and_type_ref_i);
487 break;
488 case JVM_CONSTANT_Methodref:
489 entry_name = "Methodref";
490 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i,
491 new_name_and_type_ref_i);
492 break;
493 default:
494 guarantee(false, "bad switch");
495 break;
496 }
497
498 if (klass_ref_i != new_klass_ref_i) {
499 log_trace(redefine, class, constantpool)
500 ("%s entry@%d class_index changed: %d to %d", entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i);
501 }
502 if (name_and_type_ref_i != new_name_and_type_ref_i) {
503 log_trace(redefine, class, constantpool)
504 ("%s entry@%d name_and_type_index changed: %d to %d",
505 entry_name, *merge_cp_length_p, name_and_type_ref_i, new_name_and_type_ref_i);
506 }
507
508 if (scratch_i != *merge_cp_length_p) {
509 // The new entry in *merge_cp_p is at a different index than
510 // the new entry in scratch_cp so we need to map the index values.
511 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
512 }
513 (*merge_cp_length_p)++;
514 } break;
515
516 // this is an indirect CP entry so it needs special handling
517 case JVM_CONSTANT_MethodType:
518 {
519 int ref_i = scratch_cp->method_type_index_at(scratch_i);
520 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
521 merge_cp_length_p);
522 if (new_ref_i != ref_i) {
523 log_trace(redefine, class, constantpool)
524 ("MethodType entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i);
525 }
526 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i);
527 if (scratch_i != *merge_cp_length_p) {
528 // The new entry in *merge_cp_p is at a different index than
529 // the new entry in scratch_cp so we need to map the index values.
530 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
531 }
532 (*merge_cp_length_p)++;
533 } break;
534
535 // this is an indirect CP entry so it needs special handling
536 case JVM_CONSTANT_MethodHandle:
537 {
538 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i);
539 int ref_i = scratch_cp->method_handle_index_at(scratch_i);
540 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
541 merge_cp_length_p);
542 if (new_ref_i != ref_i) {
543 log_trace(redefine, class, constantpool)
544 ("MethodHandle entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i);
545 }
546 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i);
547 if (scratch_i != *merge_cp_length_p) {
548 // The new entry in *merge_cp_p is at a different index than
549 // the new entry in scratch_cp so we need to map the index values.
550 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
551 }
552 (*merge_cp_length_p)++;
553 } break;
554
555 // this is an indirect CP entry so it needs special handling
556 case JVM_CONSTANT_Dynamic: // fall through
557 case JVM_CONSTANT_InvokeDynamic:
558 {
559 // Index of the bootstrap specifier in the operands array
560 int old_bs_i = scratch_cp->bootstrap_methods_attribute_index(scratch_i);
561 int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p,
562 merge_cp_length_p);
563 // The bootstrap method NameAndType_info index
564 int old_ref_i = scratch_cp->bootstrap_name_and_type_ref_index_at(scratch_i);
565 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
566 merge_cp_length_p);
567 if (new_bs_i != old_bs_i) {
568 log_trace(redefine, class, constantpool)
569 ("Dynamic entry@%d bootstrap_method_attr_index change: %d to %d",
570 *merge_cp_length_p, old_bs_i, new_bs_i);
571 }
572 if (new_ref_i != old_ref_i) {
573 log_trace(redefine, class, constantpool)
574 ("Dynamic entry@%d name_and_type_index change: %d to %d", *merge_cp_length_p, old_ref_i, new_ref_i);
575 }
576
577 if (scratch_cp->tag_at(scratch_i).is_dynamic_constant())
578 (*merge_cp_p)->dynamic_constant_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
579 else
580 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
581 if (scratch_i != *merge_cp_length_p) {
582 // The new entry in *merge_cp_p is at a different index than
583 // the new entry in scratch_cp so we need to map the index values.
584 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
585 }
586 (*merge_cp_length_p)++;
587 } break;
588
589 // At this stage, Class or UnresolvedClass could be in scratch_cp, but not
590 // ClassIndex
591 case JVM_CONSTANT_ClassIndex: // fall through
592
593 // Invalid is used as the tag for the second constant pool entry
594 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
595 // not be seen by itself.
596 case JVM_CONSTANT_Invalid: // fall through
597
598 // At this stage, String could be here, but not StringIndex
599 case JVM_CONSTANT_StringIndex: // fall through
600
601 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be here
602 case JVM_CONSTANT_UnresolvedClassInError: // fall through
603
604 default:
605 {
606 // leave a breadcrumb
607 jbyte bad_value = scratch_cp->tag_at(scratch_i).value();
608 ShouldNotReachHere();
609 } break;
610 } // end switch tag value
611 } // end append_entry()
612
613
614 int VM_RedefineClasses::find_or_append_indirect_entry(const constantPoolHandle& scratch_cp,
615 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) {
616
617 int new_ref_i = ref_i;
618 bool match = (ref_i < *merge_cp_length_p) &&
619 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i);
620
621 if (!match) {
622 // forward reference in *merge_cp_p or not a direct match
623 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p);
624 if (found_i != 0) {
625 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree");
626 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry.
627 new_ref_i = found_i;
628 map_index(scratch_cp, ref_i, found_i);
629 } else {
630 // no match found so we have to append this entry to *merge_cp_p
631 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p);
632 // The above call to append_entry() can only append one entry
633 // so the post call query of *merge_cp_length_p is only for
634 // the sake of consistency.
635 new_ref_i = *merge_cp_length_p - 1;
636 }
637 }
638
639 return new_ref_i;
640 } // end find_or_append_indirect_entry()
641
642
643 // Append a bootstrap specifier into the merge_cp operands that is semantically equal
644 // to the scratch_cp operands bootstrap specifier passed by the old_bs_i index.
645 // Recursively append new merge_cp entries referenced by the new bootstrap specifier.
646 void VM_RedefineClasses::append_operand(const constantPoolHandle& scratch_cp, int old_bs_i,
647 constantPoolHandle *merge_cp_p, int *merge_cp_length_p) {
648
649 int old_ref_i = scratch_cp->operand_bootstrap_method_ref_index_at(old_bs_i);
650 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
651 merge_cp_length_p);
652 if (new_ref_i != old_ref_i) {
653 log_trace(redefine, class, constantpool)
654 ("operands entry@%d bootstrap method ref_index change: %d to %d", _operands_cur_length, old_ref_i, new_ref_i);
655 }
656
657 Array<u2>* merge_ops = (*merge_cp_p)->operands();
658 int new_bs_i = _operands_cur_length;
659 // We have _operands_cur_length == 0 when the merge_cp operands is empty yet.
660 // However, the operand_offset_at(0) was set in the extend_operands() call.
661 int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0)
662 : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1);
663 int argc = scratch_cp->operand_argument_count_at(old_bs_i);
664
665 ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base);
666 merge_ops->at_put(new_base++, new_ref_i);
667 merge_ops->at_put(new_base++, argc);
668
669 for (int i = 0; i < argc; i++) {
670 int old_arg_ref_i = scratch_cp->operand_argument_index_at(old_bs_i, i);
671 int new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p,
672 merge_cp_length_p);
673 merge_ops->at_put(new_base++, new_arg_ref_i);
674 if (new_arg_ref_i != old_arg_ref_i) {
675 log_trace(redefine, class, constantpool)
676 ("operands entry@%d bootstrap method argument ref_index change: %d to %d",
677 _operands_cur_length, old_arg_ref_i, new_arg_ref_i);
678 }
679 }
680 if (old_bs_i != _operands_cur_length) {
681 // The bootstrap specifier in *merge_cp_p is at a different index than
682 // that in scratch_cp so we need to map the index values.
683 map_operand_index(old_bs_i, new_bs_i);
684 }
685 _operands_cur_length++;
686 } // end append_operand()
687
688
689 int VM_RedefineClasses::find_or_append_operand(const constantPoolHandle& scratch_cp,
690 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p) {
691
692 int new_bs_i = old_bs_i; // bootstrap specifier index
693 bool match = (old_bs_i < _operands_cur_length) &&
694 scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i);
695
696 if (!match) {
697 // forward reference in *merge_cp_p or not a direct match
698 int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p,
699 _operands_cur_length);
700 if (found_i != -1) {
701 guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree");
702 // found a matching operand somewhere else in *merge_cp_p so just need a mapping
703 new_bs_i = found_i;
704 map_operand_index(old_bs_i, found_i);
705 } else {
706 // no match found so we have to append this bootstrap specifier to *merge_cp_p
707 append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p);
708 new_bs_i = _operands_cur_length - 1;
709 }
710 }
711 return new_bs_i;
712 } // end find_or_append_operand()
713
714
715 void VM_RedefineClasses::finalize_operands_merge(const constantPoolHandle& merge_cp, TRAPS) {
716 if (merge_cp->operands() == NULL) {
717 return;
718 }
719 // Shrink the merge_cp operands
720 merge_cp->shrink_operands(_operands_cur_length, CHECK);
721
722 if (log_is_enabled(Trace, redefine, class, constantpool)) {
723 // don't want to loop unless we are tracing
724 int count = 0;
725 for (int i = 1; i < _operands_index_map_p->length(); i++) {
726 int value = _operands_index_map_p->at(i);
727 if (value != -1) {
728 log_trace(redefine, class, constantpool)("operands_index_map[%d]: old=%d new=%d", count, i, value);
729 count++;
730 }
731 }
732 }
733 // Clean-up
734 _operands_index_map_p = NULL;
735 _operands_cur_length = 0;
736 _operands_index_map_count = 0;
737 } // end finalize_operands_merge()
738
739 // Symbol* comparator for qsort
740 // The caller must have an active ResourceMark.
741 static int symcmp(const void* a, const void* b) {
742 char* astr = (*(Symbol**)a)->as_C_string();
743 char* bstr = (*(Symbol**)b)->as_C_string();
744 return strcmp(astr, bstr);
745 }
746
747 // The caller must have an active ResourceMark.
748 static jvmtiError check_attribute_arrays(const char* attr_name,
749 InstanceKlass* the_class, InstanceKlass* scratch_class,
750 Array<u2>* the_array, Array<u2>* scr_array) {
751 bool the_array_exists = the_array != Universe::the_empty_short_array();
752 bool scr_array_exists = scr_array != Universe::the_empty_short_array();
753
754 int array_len = the_array->length();
755 if (the_array_exists && scr_array_exists) {
756 if (array_len != scr_array->length()) {
757 log_trace(redefine, class)
758 ("redefined class %s attribute change error: %s len=%d changed to len=%d",
759 the_class->external_name(), attr_name, array_len, scr_array->length());
760 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
761 }
762
763 // The order of entries in the attribute array is not specified so we
764 // have to explicitly check for the same contents. We do this by copying
765 // the referenced symbols into their own arrays, sorting them and then
766 // comparing each element pair.
767
768 Symbol** the_syms = NEW_RESOURCE_ARRAY_RETURN_NULL(Symbol*, array_len);
769 Symbol** scr_syms = NEW_RESOURCE_ARRAY_RETURN_NULL(Symbol*, array_len);
770
771 if (the_syms == NULL || scr_syms == NULL) {
772 return JVMTI_ERROR_OUT_OF_MEMORY;
773 }
774
775 for (int i = 0; i < array_len; i++) {
776 int the_cp_index = the_array->at(i);
777 int scr_cp_index = scr_array->at(i);
778 the_syms[i] = the_class->constants()->klass_name_at(the_cp_index);
779 scr_syms[i] = scratch_class->constants()->klass_name_at(scr_cp_index);
780 }
781
782 qsort(the_syms, array_len, sizeof(Symbol*), symcmp);
783 qsort(scr_syms, array_len, sizeof(Symbol*), symcmp);
784
785 for (int i = 0; i < array_len; i++) {
786 if (the_syms[i] != scr_syms[i]) {
787 log_info(redefine, class)
788 ("redefined class %s attribute change error: %s[%d]: %s changed to %s",
789 the_class->external_name(), attr_name, i,
790 the_syms[i]->as_C_string(), scr_syms[i]->as_C_string());
791 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
792 }
793 }
794 } else if (the_array_exists ^ scr_array_exists) {
795 const char* action_str = (the_array_exists) ? "removed" : "added";
796 log_info(redefine, class)
797 ("redefined class %s attribute change error: %s attribute %s",
798 the_class->external_name(), attr_name, action_str);
799 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
800 }
801 return JVMTI_ERROR_NONE;
802 }
803
804 static jvmtiError check_nest_attributes(InstanceKlass* the_class,
805 InstanceKlass* scratch_class) {
806 // Check whether the class NestHost attribute has been changed.
807 Thread* thread = Thread::current();
808 ResourceMark rm(thread);
809 u2 the_nest_host_idx = the_class->nest_host_index();
810 u2 scr_nest_host_idx = scratch_class->nest_host_index();
811
812 if (the_nest_host_idx != 0 && scr_nest_host_idx != 0) {
813 Symbol* the_sym = the_class->constants()->klass_name_at(the_nest_host_idx);
814 Symbol* scr_sym = scratch_class->constants()->klass_name_at(scr_nest_host_idx);
815 if (the_sym != scr_sym) {
816 log_info(redefine, class, nestmates)
817 ("redefined class %s attribute change error: NestHost class: %s replaced with: %s",
818 the_class->external_name(), the_sym->as_C_string(), scr_sym->as_C_string());
819 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
820 }
821 } else if ((the_nest_host_idx == 0) ^ (scr_nest_host_idx == 0)) {
822 const char* action_str = (the_nest_host_idx != 0) ? "removed" : "added";
823 log_info(redefine, class, nestmates)
824 ("redefined class %s attribute change error: NestHost attribute %s",
825 the_class->external_name(), action_str);
826 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
827 }
828
829 // Check whether the class NestMembers attribute has been changed.
830 return check_attribute_arrays("NestMembers",
831 the_class, scratch_class,
832 the_class->nest_members(),
833 scratch_class->nest_members());
834 }
835
836 // Return an error status if the class Record attribute was changed.
837 static jvmtiError check_record_attribute(InstanceKlass* the_class, InstanceKlass* scratch_class) {
838 // Get lists of record components.
839 Array<RecordComponent*>* the_record = the_class->record_components();
840 Array<RecordComponent*>* scr_record = scratch_class->record_components();
841 bool the_record_exists = the_record != NULL;
842 bool scr_record_exists = scr_record != NULL;
843
844 if (the_record_exists && scr_record_exists) {
845 int the_num_components = the_record->length();
846 int scr_num_components = scr_record->length();
847 if (the_num_components != scr_num_components) {
848 log_info(redefine, class, record)
849 ("redefined class %s attribute change error: Record num_components=%d changed to num_components=%d",
850 the_class->external_name(), the_num_components, scr_num_components);
851 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
852 }
853
854 // Compare each field in each record component.
855 ConstantPool* the_cp = the_class->constants();
856 ConstantPool* scr_cp = scratch_class->constants();
857 for (int x = 0; x < the_num_components; x++) {
858 RecordComponent* the_component = the_record->at(x);
859 RecordComponent* scr_component = scr_record->at(x);
860 const Symbol* const the_name = the_cp->symbol_at(the_component->name_index());
861 const Symbol* const scr_name = scr_cp->symbol_at(scr_component->name_index());
862 const Symbol* const the_descr = the_cp->symbol_at(the_component->descriptor_index());
863 const Symbol* const scr_descr = scr_cp->symbol_at(scr_component->descriptor_index());
864 if (the_name != scr_name || the_descr != scr_descr) {
865 log_info(redefine, class, record)
866 ("redefined class %s attribute change error: Record name_index, descriptor_index, and/or attributes_count changed",
867 the_class->external_name());
868 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
869 }
870
871 int the_gen_sig = the_component->generic_signature_index();
872 int scr_gen_sig = scr_component->generic_signature_index();
873 const Symbol* const the_gen_sig_sym = (the_gen_sig == 0 ? NULL :
874 the_cp->symbol_at(the_component->generic_signature_index()));
875 const Symbol* const scr_gen_sig_sym = (scr_gen_sig == 0 ? NULL :
876 scr_cp->symbol_at(scr_component->generic_signature_index()));
877 if (the_gen_sig_sym != scr_gen_sig_sym) {
878 log_info(redefine, class, record)
879 ("redefined class %s attribute change error: Record generic_signature attribute changed",
880 the_class->external_name());
881 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
882 }
883
884 // It's okay if a record component's annotations were changed.
885 }
886
887 } else if (the_record_exists ^ scr_record_exists) {
888 const char* action_str = (the_record_exists) ? "removed" : "added";
889 log_info(redefine, class, record)
890 ("redefined class %s attribute change error: Record attribute %s",
891 the_class->external_name(), action_str);
892 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
893 }
894
895 return JVMTI_ERROR_NONE;
896 }
897
898
899 static jvmtiError check_permitted_subclasses_attribute(InstanceKlass* the_class,
900 InstanceKlass* scratch_class) {
901 Thread* thread = Thread::current();
902 ResourceMark rm(thread);
903
904 // Check whether the class PermittedSubclasses attribute has been changed.
905 return check_attribute_arrays("PermittedSubclasses",
906 the_class, scratch_class,
907 the_class->permitted_subclasses(),
908 scratch_class->permitted_subclasses());
909 }
910
911 static jvmtiError check_preload_attribute(InstanceKlass* the_class,
912 InstanceKlass* scratch_class) {
913 Thread* thread = Thread::current();
914 ResourceMark rm(thread);
915
916 // Check whether the class Preload attribute has been changed.
917 return check_attribute_arrays("Preload",
918 the_class, scratch_class,
919 the_class->preload_classes(),
920 scratch_class->preload_classes());
921 }
922
923 static bool can_add_or_delete(Method* m) {
924 // Compatibility mode
925 return (AllowRedefinitionToAddDeleteMethods &&
926 (m->is_private() && (m->is_static() || m->is_final())));
927 }
928
929 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions(
930 InstanceKlass* the_class,
931 InstanceKlass* scratch_class) {
932 int i;
933
934 // Check superclasses, or rather their names, since superclasses themselves can be
935 // requested to replace.
936 // Check for NULL superclass first since this might be java.lang.Object
937 if (the_class->super() != scratch_class->super() &&
938 (the_class->super() == NULL || scratch_class->super() == NULL ||
939 the_class->super()->name() !=
940 scratch_class->super()->name())) {
941 log_info(redefine, class, normalize)
942 ("redefined class %s superclass change error: superclass changed from %s to %s.",
943 the_class->external_name(),
944 the_class->super() == NULL ? "NULL" : the_class->super()->external_name(),
945 scratch_class->super() == NULL ? "NULL" : scratch_class->super()->external_name());
946 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
947 }
948
949 // Check if the number, names and order of directly implemented interfaces are the same.
950 // I think in principle we should just check if the sets of names of directly implemented
951 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the
952 // .java file, also changes in .class file) should not matter. However, comparing sets is
953 // technically a bit more difficult, and, more importantly, I am not sure at present that the
954 // order of interfaces does not matter on the implementation level, i.e. that the VM does not
955 // rely on it somewhere.
956 Array<InstanceKlass*>* k_interfaces = the_class->local_interfaces();
957 Array<InstanceKlass*>* k_new_interfaces = scratch_class->local_interfaces();
958 int n_intfs = k_interfaces->length();
959 if (n_intfs != k_new_interfaces->length()) {
960 log_info(redefine, class, normalize)
961 ("redefined class %s interfaces change error: number of implemented interfaces changed from %d to %d.",
962 the_class->external_name(), n_intfs, k_new_interfaces->length());
963 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
964 }
965 for (i = 0; i < n_intfs; i++) {
966 if (k_interfaces->at(i)->name() !=
967 k_new_interfaces->at(i)->name()) {
968 log_info(redefine, class, normalize)
969 ("redefined class %s interfaces change error: interface changed from %s to %s.",
970 the_class->external_name(),
971 k_interfaces->at(i)->external_name(), k_new_interfaces->at(i)->external_name());
972 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
973 }
974 }
975
976 // Check whether class is in the error init state.
977 if (the_class->is_in_error_state()) {
978 log_info(redefine, class, normalize)
979 ("redefined class %s is in error init state.", the_class->external_name());
980 // TBD #5057930: special error code is needed in 1.6
981 return JVMTI_ERROR_INVALID_CLASS;
982 }
983
984 // Check whether the nest-related attributes have been changed.
985 jvmtiError err = check_nest_attributes(the_class, scratch_class);
986 if (err != JVMTI_ERROR_NONE) {
987 return err;
988 }
989
990 // Check whether the Record attribute has been changed.
991 err = check_record_attribute(the_class, scratch_class);
992 if (err != JVMTI_ERROR_NONE) {
993 return err;
994 }
995
996 // Check whether the PermittedSubclasses attribute has been changed.
997 err = check_permitted_subclasses_attribute(the_class, scratch_class);
998 if (err != JVMTI_ERROR_NONE) {
999 return err;
1000 }
1001
1002 // Check whether the Preload attribute has been changed.
1003 err = check_preload_attribute(the_class, scratch_class);
1004 if (err != JVMTI_ERROR_NONE) {
1005 return err;
1006 }
1007
1008 // Check whether class modifiers are the same.
1009 jushort old_flags = (jushort) the_class->access_flags().get_flags();
1010 jushort new_flags = (jushort) scratch_class->access_flags().get_flags();
1011 if (old_flags != new_flags) {
1012 log_info(redefine, class, normalize)
1013 ("redefined class %s modifiers change error: modifiers changed from %d to %d.",
1014 the_class->external_name(), old_flags, new_flags);
1015 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED;
1016 }
1017
1018 // Check if the number, names, types and order of fields declared in these classes
1019 // are the same.
1020 JavaFieldStream old_fs(the_class);
1021 JavaFieldStream new_fs(scratch_class);
1022 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) {
1023 // name and signature
1024 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index());
1025 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index());
1026 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index());
1027 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index());
1028 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) {
1029 log_info(redefine, class, normalize)
1030 ("redefined class %s fields change error: field %s %s changed to %s %s.",
1031 the_class->external_name(),
1032 sig_sym1->as_C_string(), name_sym1->as_C_string(),
1033 sig_sym2->as_C_string(), name_sym2->as_C_string());
1034 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
1035 }
1036 // offset
1037 if (old_fs.offset() != new_fs.offset()) {
1038 log_info(redefine, class, normalize)
1039 ("redefined class %s field %s change error: offset changed from %d to %d.",
1040 the_class->external_name(), name_sym2->as_C_string(), old_fs.offset(), new_fs.offset());
1041 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
1042 }
1043 // access
1044 old_flags = old_fs.access_flags().as_short();
1045 new_flags = new_fs.access_flags().as_short();
1046 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) {
1047 log_info(redefine, class, normalize)
1048 ("redefined class %s field %s change error: modifiers changed from %d to %d.",
1049 the_class->external_name(), name_sym2->as_C_string(), old_flags, new_flags);
1050 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
1051 }
1052 }
1053
1054 // If both streams aren't done then we have a differing number of
1055 // fields.
1056 if (!old_fs.done() || !new_fs.done()) {
1057 const char* action = old_fs.done() ? "added" : "deleted";
1058 log_info(redefine, class, normalize)
1059 ("redefined class %s fields change error: some fields were %s.",
1060 the_class->external_name(), action);
1061 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
1062 }
1063
1064 // Do a parallel walk through the old and new methods. Detect
1065 // cases where they match (exist in both), have been added in
1066 // the new methods, or have been deleted (exist only in the
1067 // old methods). The class file parser places methods in order
1068 // by method name, but does not order overloaded methods by
1069 // signature. In order to determine what fate befell the methods,
1070 // this code places the overloaded new methods that have matching
1071 // old methods in the same order as the old methods and places
1072 // new overloaded methods at the end of overloaded methods of
1073 // that name. The code for this order normalization is adapted
1074 // from the algorithm used in InstanceKlass::find_method().
1075 // Since we are swapping out of order entries as we find them,
1076 // we only have to search forward through the overloaded methods.
1077 // Methods which are added and have the same name as an existing
1078 // method (but different signature) will be put at the end of
1079 // the methods with that name, and the name mismatch code will
1080 // handle them.
1081 Array<Method*>* k_old_methods(the_class->methods());
1082 Array<Method*>* k_new_methods(scratch_class->methods());
1083 int n_old_methods = k_old_methods->length();
1084 int n_new_methods = k_new_methods->length();
1085 Thread* thread = Thread::current();
1086
1087 int ni = 0;
1088 int oi = 0;
1089 while (true) {
1090 Method* k_old_method;
1091 Method* k_new_method;
1092 enum { matched, added, deleted, undetermined } method_was = undetermined;
1093
1094 if (oi >= n_old_methods) {
1095 if (ni >= n_new_methods) {
1096 break; // we've looked at everything, done
1097 }
1098 // New method at the end
1099 k_new_method = k_new_methods->at(ni);
1100 method_was = added;
1101 } else if (ni >= n_new_methods) {
1102 // Old method, at the end, is deleted
1103 k_old_method = k_old_methods->at(oi);
1104 method_was = deleted;
1105 } else {
1106 // There are more methods in both the old and new lists
1107 k_old_method = k_old_methods->at(oi);
1108 k_new_method = k_new_methods->at(ni);
1109 if (k_old_method->name() != k_new_method->name()) {
1110 // Methods are sorted by method name, so a mismatch means added
1111 // or deleted
1112 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) {
1113 method_was = added;
1114 } else {
1115 method_was = deleted;
1116 }
1117 } else if (k_old_method->signature() == k_new_method->signature()) {
1118 // Both the name and signature match
1119 method_was = matched;
1120 } else {
1121 // The name matches, but the signature doesn't, which means we have to
1122 // search forward through the new overloaded methods.
1123 int nj; // outside the loop for post-loop check
1124 for (nj = ni + 1; nj < n_new_methods; nj++) {
1125 Method* m = k_new_methods->at(nj);
1126 if (k_old_method->name() != m->name()) {
1127 // reached another method name so no more overloaded methods
1128 method_was = deleted;
1129 break;
1130 }
1131 if (k_old_method->signature() == m->signature()) {
1132 // found a match so swap the methods
1133 k_new_methods->at_put(ni, m);
1134 k_new_methods->at_put(nj, k_new_method);
1135 k_new_method = m;
1136 method_was = matched;
1137 break;
1138 }
1139 }
1140
1141 if (nj >= n_new_methods) {
1142 // reached the end without a match; so method was deleted
1143 method_was = deleted;
1144 }
1145 }
1146 }
1147
1148 switch (method_was) {
1149 case matched:
1150 // methods match, be sure modifiers do too
1151 old_flags = (jushort) k_old_method->access_flags().get_flags();
1152 new_flags = (jushort) k_new_method->access_flags().get_flags();
1153 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) {
1154 log_info(redefine, class, normalize)
1155 ("redefined class %s method %s modifiers error: modifiers changed from %d to %d",
1156 the_class->external_name(), k_old_method->name_and_sig_as_C_string(), old_flags, new_flags);
1157 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED;
1158 }
1159 {
1160 u2 new_num = k_new_method->method_idnum();
1161 u2 old_num = k_old_method->method_idnum();
1162 if (new_num != old_num) {
1163 Method* idnum_owner = scratch_class->method_with_idnum(old_num);
1164 if (idnum_owner != NULL) {
1165 // There is already a method assigned this idnum -- switch them
1166 // Take current and original idnum from the new_method
1167 idnum_owner->set_method_idnum(new_num);
1168 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum());
1169 }
1170 // Take current and original idnum from the old_method
1171 k_new_method->set_method_idnum(old_num);
1172 k_new_method->set_orig_method_idnum(k_old_method->orig_method_idnum());
1173 if (thread->has_pending_exception()) {
1174 return JVMTI_ERROR_OUT_OF_MEMORY;
1175 }
1176 }
1177 }
1178 log_trace(redefine, class, normalize)
1179 ("Method matched: new: %s [%d] == old: %s [%d]",
1180 k_new_method->name_and_sig_as_C_string(), ni, k_old_method->name_and_sig_as_C_string(), oi);
1181 // advance to next pair of methods
1182 ++oi;
1183 ++ni;
1184 break;
1185 case added:
1186 // method added, see if it is OK
1187 if (!can_add_or_delete(k_new_method)) {
1188 log_info(redefine, class, normalize)
1189 ("redefined class %s methods error: added method: %s [%d]",
1190 the_class->external_name(), k_new_method->name_and_sig_as_C_string(), ni);
1191 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
1192 }
1193 {
1194 u2 num = the_class->next_method_idnum();
1195 if (num == ConstMethod::UNSET_IDNUM) {
1196 // cannot add any more methods
1197 log_info(redefine, class, normalize)
1198 ("redefined class %s methods error: can't create ID for new method %s [%d]",
1199 the_class->external_name(), k_new_method->name_and_sig_as_C_string(), ni);
1200 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
1201 }
1202 u2 new_num = k_new_method->method_idnum();
1203 Method* idnum_owner = scratch_class->method_with_idnum(num);
1204 if (idnum_owner != NULL) {
1205 // There is already a method assigned this idnum -- switch them
1206 // Take current and original idnum from the new_method
1207 idnum_owner->set_method_idnum(new_num);
1208 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum());
1209 }
1210 k_new_method->set_method_idnum(num);
1211 k_new_method->set_orig_method_idnum(num);
1212 if (thread->has_pending_exception()) {
1213 return JVMTI_ERROR_OUT_OF_MEMORY;
1214 }
1215 }
1216 log_trace(redefine, class, normalize)
1217 ("Method added: new: %s [%d]", k_new_method->name_and_sig_as_C_string(), ni);
1218 ++ni; // advance to next new method
1219 break;
1220 case deleted:
1221 // method deleted, see if it is OK
1222 if (!can_add_or_delete(k_old_method)) {
1223 log_info(redefine, class, normalize)
1224 ("redefined class %s methods error: deleted method %s [%d]",
1225 the_class->external_name(), k_old_method->name_and_sig_as_C_string(), oi);
1226 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED;
1227 }
1228 log_trace(redefine, class, normalize)
1229 ("Method deleted: old: %s [%d]", k_old_method->name_and_sig_as_C_string(), oi);
1230 ++oi; // advance to next old method
1231 break;
1232 default:
1233 ShouldNotReachHere();
1234 }
1235 }
1236
1237 return JVMTI_ERROR_NONE;
1238 }
1239
1240
1241 // Find new constant pool index value for old constant pool index value
1242 // by seaching the index map. Returns zero (0) if there is no mapped
1243 // value for the old constant pool index.
1244 int VM_RedefineClasses::find_new_index(int old_index) {
1245 if (_index_map_count == 0) {
1246 // map is empty so nothing can be found
1247 return 0;
1248 }
1249
1250 if (old_index < 1 || old_index >= _index_map_p->length()) {
1251 // The old_index is out of range so it is not mapped. This should
1252 // not happen in regular constant pool merging use, but it can
1253 // happen if a corrupt annotation is processed.
1254 return 0;
1255 }
1256
1257 int value = _index_map_p->at(old_index);
1258 if (value == -1) {
1259 // the old_index is not mapped
1260 return 0;
1261 }
1262
1263 return value;
1264 } // end find_new_index()
1265
1266
1267 // Find new bootstrap specifier index value for old bootstrap specifier index
1268 // value by seaching the index map. Returns unused index (-1) if there is
1269 // no mapped value for the old bootstrap specifier index.
1270 int VM_RedefineClasses::find_new_operand_index(int old_index) {
1271 if (_operands_index_map_count == 0) {
1272 // map is empty so nothing can be found
1273 return -1;
1274 }
1275
1276 if (old_index == -1 || old_index >= _operands_index_map_p->length()) {
1277 // The old_index is out of range so it is not mapped.
1278 // This should not happen in regular constant pool merging use.
1279 return -1;
1280 }
1281
1282 int value = _operands_index_map_p->at(old_index);
1283 if (value == -1) {
1284 // the old_index is not mapped
1285 return -1;
1286 }
1287
1288 return value;
1289 } // end find_new_operand_index()
1290
1291
1292 // Returns true if the current mismatch is due to a resolved/unresolved
1293 // class pair. Otherwise, returns false.
1294 bool VM_RedefineClasses::is_unresolved_class_mismatch(const constantPoolHandle& cp1,
1295 int index1, const constantPoolHandle& cp2, int index2) {
1296
1297 jbyte t1 = cp1->tag_at(index1).value();
1298 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) {
1299 return false; // wrong entry type; not our special case
1300 }
1301
1302 jbyte t2 = cp2->tag_at(index2).value();
1303 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) {
1304 return false; // wrong entry type; not our special case
1305 }
1306
1307 if (t1 == t2) {
1308 return false; // not a mismatch; not our special case
1309 }
1310
1311 char *s1 = cp1->klass_name_at(index1)->as_C_string();
1312 char *s2 = cp2->klass_name_at(index2)->as_C_string();
1313 if (strcmp(s1, s2) != 0) {
1314 return false; // strings don't match; not our special case
1315 }
1316
1317 return true; // made it through the gauntlet; this is our special case
1318 } // end is_unresolved_class_mismatch()
1319
1320
1321 // The bug 6214132 caused the verification to fail.
1322 // 1. What's done in RedefineClasses() before verification:
1323 // a) A reference to the class being redefined (_the_class) and a
1324 // reference to new version of the class (_scratch_class) are
1325 // saved here for use during the bytecode verification phase of
1326 // RedefineClasses.
1327 // b) The _java_mirror field from _the_class is copied to the
1328 // _java_mirror field in _scratch_class. This means that a jclass
1329 // returned for _the_class or _scratch_class will refer to the
1330 // same Java mirror. The verifier will see the "one true mirror"
1331 // for the class being verified.
1332 // 2. See comments in JvmtiThreadState for what is done during verification.
1333
1334 class RedefineVerifyMark : public StackObj {
1335 private:
1336 JvmtiThreadState* _state;
1337 Klass* _scratch_class;
1338 Handle _scratch_mirror;
1339
1340 public:
1341
1342 RedefineVerifyMark(Klass* the_class, Klass* scratch_class,
1343 JvmtiThreadState* state) : _state(state), _scratch_class(scratch_class)
1344 {
1345 _state->set_class_versions_map(the_class, scratch_class);
1346 _scratch_mirror = Handle(_state->get_thread(), _scratch_class->java_mirror());
1347 _scratch_class->replace_java_mirror(the_class->java_mirror());
1348 }
1349
1350 ~RedefineVerifyMark() {
1351 // Restore the scratch class's mirror, so when scratch_class is removed
1352 // the correct mirror pointing to it can be cleared.
1353 _scratch_class->replace_java_mirror(_scratch_mirror());
1354 _state->clear_class_versions_map();
1355 }
1356 };
1357
1358
1359 jvmtiError VM_RedefineClasses::load_new_class_versions() {
1360
1361 // For consistency allocate memory using os::malloc wrapper.
1362 _scratch_classes = (InstanceKlass**)
1363 os::malloc(sizeof(InstanceKlass*) * _class_count, mtClass);
1364 if (_scratch_classes == NULL) {
1365 return JVMTI_ERROR_OUT_OF_MEMORY;
1366 }
1367 // Zero initialize the _scratch_classes array.
1368 for (int i = 0; i < _class_count; i++) {
1369 _scratch_classes[i] = NULL;
1370 }
1371
1372 JavaThread* current = JavaThread::current();
1373 ResourceMark rm(current);
1374
1375 JvmtiThreadState *state = JvmtiThreadState::state_for(current);
1376 // state can only be NULL if the current thread is exiting which
1377 // should not happen since we're trying to do a RedefineClasses
1378 guarantee(state != NULL, "exiting thread calling load_new_class_versions");
1379 for (int i = 0; i < _class_count; i++) {
1380 // Create HandleMark so that any handles created while loading new class
1381 // versions are deleted. Constant pools are deallocated while merging
1382 // constant pools
1383 HandleMark hm(current);
1384 InstanceKlass* the_class = get_ik(_class_defs[i].klass);
1385
1386 log_debug(redefine, class, load)
1387 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)",
1388 the_class->external_name(), _class_load_kind, os::available_memory() >> 10);
1389
1390 ClassFileStream st((u1*)_class_defs[i].class_bytes,
1391 _class_defs[i].class_byte_count,
1392 "__VM_RedefineClasses__",
1393 ClassFileStream::verify);
1394
1395 // Set redefined class handle in JvmtiThreadState class.
1396 // This redefined class is sent to agent event handler for class file
1397 // load hook event.
1398 state->set_class_being_redefined(the_class, _class_load_kind);
1399
1400 JavaThread* THREAD = current; // For exception macros.
1401 ExceptionMark em(THREAD);
1402 Handle protection_domain(THREAD, the_class->protection_domain());
1403 ClassLoadInfo cl_info(protection_domain);
1404 // Parse and create a class from the bytes, but this class isn't added
1405 // to the dictionary, so do not call resolve_from_stream.
1406 InstanceKlass* scratch_class = KlassFactory::create_from_stream(&st,
1407 the_class->name(),
1408 the_class->class_loader_data(),
1409 cl_info,
1410 THREAD);
1411
1412 // Clear class_being_redefined just to be sure.
1413 state->clear_class_being_redefined();
1414
1415 // TODO: if this is retransform, and nothing changed we can skip it
1416
1417 // Need to clean up allocated InstanceKlass if there's an error so assign
1418 // the result here. Caller deallocates all the scratch classes in case of
1419 // an error.
1420 _scratch_classes[i] = scratch_class;
1421
1422 if (HAS_PENDING_EXCEPTION) {
1423 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1424 log_info(redefine, class, load, exceptions)("create_from_stream exception: '%s'", ex_name->as_C_string());
1425 CLEAR_PENDING_EXCEPTION;
1426
1427 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) {
1428 return JVMTI_ERROR_UNSUPPORTED_VERSION;
1429 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) {
1430 return JVMTI_ERROR_INVALID_CLASS_FORMAT;
1431 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) {
1432 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION;
1433 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
1434 // The message will be "XXX (wrong name: YYY)"
1435 return JVMTI_ERROR_NAMES_DONT_MATCH;
1436 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1437 return JVMTI_ERROR_OUT_OF_MEMORY;
1438 } else { // Just in case more exceptions can be thrown..
1439 return JVMTI_ERROR_FAILS_VERIFICATION;
1440 }
1441 }
1442
1443 // Ensure class is linked before redefine
1444 if (!the_class->is_linked()) {
1445 the_class->link_class(THREAD);
1446 if (HAS_PENDING_EXCEPTION) {
1447 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1448 oop message = java_lang_Throwable::message(PENDING_EXCEPTION);
1449 if (message != NULL) {
1450 char* ex_msg = java_lang_String::as_utf8_string(message);
1451 log_info(redefine, class, load, exceptions)("link_class exception: '%s %s'",
1452 ex_name->as_C_string(), ex_msg);
1453 } else {
1454 log_info(redefine, class, load, exceptions)("link_class exception: '%s'",
1455 ex_name->as_C_string());
1456 }
1457 CLEAR_PENDING_EXCEPTION;
1458 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1459 return JVMTI_ERROR_OUT_OF_MEMORY;
1460 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
1461 return JVMTI_ERROR_INVALID_CLASS;
1462 } else {
1463 return JVMTI_ERROR_INTERNAL;
1464 }
1465 }
1466 }
1467
1468 // Do the validity checks in compare_and_normalize_class_versions()
1469 // before verifying the byte codes. By doing these checks first, we
1470 // limit the number of functions that require redirection from
1471 // the_class to scratch_class. In particular, we don't have to
1472 // modify JNI GetSuperclass() and thus won't change its performance.
1473 jvmtiError res = compare_and_normalize_class_versions(the_class,
1474 scratch_class);
1475 if (res != JVMTI_ERROR_NONE) {
1476 return res;
1477 }
1478
1479 // verify what the caller passed us
1480 {
1481 // The bug 6214132 caused the verification to fail.
1482 // Information about the_class and scratch_class is temporarily
1483 // recorded into jvmtiThreadState. This data is used to redirect
1484 // the_class to scratch_class in the JVM_* functions called by the
1485 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed
1486 // description.
1487 RedefineVerifyMark rvm(the_class, scratch_class, state);
1488 Verifier::verify(scratch_class, true, THREAD);
1489 }
1490
1491 if (HAS_PENDING_EXCEPTION) {
1492 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1493 log_info(redefine, class, load, exceptions)("verify_byte_codes exception: '%s'", ex_name->as_C_string());
1494 CLEAR_PENDING_EXCEPTION;
1495 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1496 return JVMTI_ERROR_OUT_OF_MEMORY;
1497 } else {
1498 // tell the caller the bytecodes are bad
1499 return JVMTI_ERROR_FAILS_VERIFICATION;
1500 }
1501 }
1502
1503 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD);
1504 if (HAS_PENDING_EXCEPTION) {
1505 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1506 log_info(redefine, class, load, exceptions)("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string());
1507 CLEAR_PENDING_EXCEPTION;
1508 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1509 return JVMTI_ERROR_OUT_OF_MEMORY;
1510 } else {
1511 return JVMTI_ERROR_INTERNAL;
1512 }
1513 }
1514
1515 #ifdef ASSERT
1516 {
1517 // verify what we have done during constant pool merging
1518 {
1519 RedefineVerifyMark rvm(the_class, scratch_class, state);
1520 Verifier::verify(scratch_class, true, THREAD);
1521 }
1522
1523 if (HAS_PENDING_EXCEPTION) {
1524 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1525 log_info(redefine, class, load, exceptions)
1526 ("verify_byte_codes post merge-CP exception: '%s'", ex_name->as_C_string());
1527 CLEAR_PENDING_EXCEPTION;
1528 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1529 return JVMTI_ERROR_OUT_OF_MEMORY;
1530 } else {
1531 // tell the caller that constant pool merging screwed up
1532 return JVMTI_ERROR_INTERNAL;
1533 }
1534 }
1535 }
1536 #endif // ASSERT
1537
1538 Rewriter::rewrite(scratch_class, THREAD);
1539 if (!HAS_PENDING_EXCEPTION) {
1540 scratch_class->link_methods(THREAD);
1541 }
1542 if (HAS_PENDING_EXCEPTION) {
1543 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1544 log_info(redefine, class, load, exceptions)
1545 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string());
1546 CLEAR_PENDING_EXCEPTION;
1547 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1548 return JVMTI_ERROR_OUT_OF_MEMORY;
1549 } else {
1550 return JVMTI_ERROR_INTERNAL;
1551 }
1552 }
1553
1554 log_debug(redefine, class, load)
1555 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)", the_class->external_name(), os::available_memory() >> 10);
1556 }
1557
1558 return JVMTI_ERROR_NONE;
1559 }
1560
1561
1562 // Map old_index to new_index as needed. scratch_cp is only needed
1563 // for log calls.
1564 void VM_RedefineClasses::map_index(const constantPoolHandle& scratch_cp,
1565 int old_index, int new_index) {
1566 if (find_new_index(old_index) != 0) {
1567 // old_index is already mapped
1568 return;
1569 }
1570
1571 if (old_index == new_index) {
1572 // no mapping is needed
1573 return;
1574 }
1575
1576 _index_map_p->at_put(old_index, new_index);
1577 _index_map_count++;
1578
1579 log_trace(redefine, class, constantpool)
1580 ("mapped tag %d at index %d to %d", scratch_cp->tag_at(old_index).value(), old_index, new_index);
1581 } // end map_index()
1582
1583
1584 // Map old_index to new_index as needed.
1585 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) {
1586 if (find_new_operand_index(old_index) != -1) {
1587 // old_index is already mapped
1588 return;
1589 }
1590
1591 if (old_index == new_index) {
1592 // no mapping is needed
1593 return;
1594 }
1595
1596 _operands_index_map_p->at_put(old_index, new_index);
1597 _operands_index_map_count++;
1598
1599 log_trace(redefine, class, constantpool)("mapped bootstrap specifier at index %d to %d", old_index, new_index);
1600 } // end map_index()
1601
1602
1603 // Merge old_cp and scratch_cp and return the results of the merge via
1604 // merge_cp_p. The number of entries in *merge_cp_p is returned via
1605 // merge_cp_length_p. The entries in old_cp occupy the same locations
1606 // in *merge_cp_p. Also creates a map of indices from entries in
1607 // scratch_cp to the corresponding entry in *merge_cp_p. Index map
1608 // entries are only created for entries in scratch_cp that occupy a
1609 // different location in *merged_cp_p.
1610 bool VM_RedefineClasses::merge_constant_pools(const constantPoolHandle& old_cp,
1611 const constantPoolHandle& scratch_cp, constantPoolHandle *merge_cp_p,
1612 int *merge_cp_length_p, TRAPS) {
1613
1614 if (merge_cp_p == NULL) {
1615 assert(false, "caller must provide scratch constantPool");
1616 return false; // robustness
1617 }
1618 if (merge_cp_length_p == NULL) {
1619 assert(false, "caller must provide scratch CP length");
1620 return false; // robustness
1621 }
1622 // Worst case we need old_cp->length() + scratch_cp()->length(),
1623 // but the caller might be smart so make sure we have at least
1624 // the minimum.
1625 if ((*merge_cp_p)->length() < old_cp->length()) {
1626 assert(false, "merge area too small");
1627 return false; // robustness
1628 }
1629
1630 log_info(redefine, class, constantpool)("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(), scratch_cp->length());
1631
1632 {
1633 // Pass 0:
1634 // The old_cp is copied to *merge_cp_p; this means that any code
1635 // using old_cp does not have to change. This work looks like a
1636 // perfect fit for ConstantPool*::copy_cp_to(), but we need to
1637 // handle one special case:
1638 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass
1639 // This will make verification happy.
1640
1641 int old_i; // index into old_cp
1642
1643 // index zero (0) is not used in constantPools
1644 for (old_i = 1; old_i < old_cp->length(); old_i++) {
1645 // leave debugging crumb
1646 jbyte old_tag = old_cp->tag_at(old_i).value();
1647 switch (old_tag) {
1648 case JVM_CONSTANT_Class:
1649 case JVM_CONSTANT_UnresolvedClass:
1650 // revert the copy to JVM_CONSTANT_UnresolvedClass
1651 // May be resolving while calling this so do the same for
1652 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition)
1653 (*merge_cp_p)->temp_unresolved_klass_at_put(old_i,
1654 old_cp->klass_name_index_at(old_i));
1655 break;
1656
1657 case JVM_CONSTANT_Double:
1658 case JVM_CONSTANT_Long:
1659 // just copy the entry to *merge_cp_p, but double and long take
1660 // two constant pool entries
1661 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i);
1662 old_i++;
1663 break;
1664
1665 default:
1666 // just copy the entry to *merge_cp_p
1667 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i);
1668 break;
1669 }
1670 } // end for each old_cp entry
1671
1672 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_false);
1673 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_false);
1674
1675 // We don't need to sanity check that *merge_cp_length_p is within
1676 // *merge_cp_p bounds since we have the minimum on-entry check above.
1677 (*merge_cp_length_p) = old_i;
1678 }
1679
1680 // merge_cp_len should be the same as old_cp->length() at this point
1681 // so this trace message is really a "warm-and-breathing" message.
1682 log_debug(redefine, class, constantpool)("after pass 0: merge_cp_len=%d", *merge_cp_length_p);
1683
1684 int scratch_i; // index into scratch_cp
1685 {
1686 // Pass 1a:
1687 // Compare scratch_cp entries to the old_cp entries that we have
1688 // already copied to *merge_cp_p. In this pass, we are eliminating
1689 // exact duplicates (matching entry at same index) so we only
1690 // compare entries in the common indice range.
1691 int increment = 1;
1692 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length());
1693 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) {
1694 switch (scratch_cp->tag_at(scratch_i).value()) {
1695 case JVM_CONSTANT_Double:
1696 case JVM_CONSTANT_Long:
1697 // double and long take two constant pool entries
1698 increment = 2;
1699 break;
1700
1701 default:
1702 increment = 1;
1703 break;
1704 }
1705
1706 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p, scratch_i);
1707 if (match) {
1708 // found a match at the same index so nothing more to do
1709 continue;
1710 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i,
1711 *merge_cp_p, scratch_i)) {
1712 // The mismatch in compare_entry_to() above is because of a
1713 // resolved versus unresolved class entry at the same index
1714 // with the same string value. Since Pass 0 reverted any
1715 // class entries to unresolved class entries in *merge_cp_p,
1716 // we go with the unresolved class entry.
1717 continue;
1718 }
1719
1720 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p);
1721 if (found_i != 0) {
1722 guarantee(found_i != scratch_i,
1723 "compare_entry_to() and find_matching_entry() do not agree");
1724
1725 // Found a matching entry somewhere else in *merge_cp_p so
1726 // just need a mapping entry.
1727 map_index(scratch_cp, scratch_i, found_i);
1728 continue;
1729 }
1730
1731 // The find_matching_entry() call above could fail to find a match
1732 // due to a resolved versus unresolved class or string entry situation
1733 // like we solved above with the is_unresolved_*_mismatch() calls.
1734 // However, we would have to call is_unresolved_*_mismatch() over
1735 // all of *merge_cp_p (potentially) and that doesn't seem to be
1736 // worth the time.
1737
1738 // No match found so we have to append this entry and any unique
1739 // referenced entries to *merge_cp_p.
1740 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p);
1741 }
1742 }
1743
1744 log_debug(redefine, class, constantpool)
1745 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1746 *merge_cp_length_p, scratch_i, _index_map_count);
1747
1748 if (scratch_i < scratch_cp->length()) {
1749 // Pass 1b:
1750 // old_cp is smaller than scratch_cp so there are entries in
1751 // scratch_cp that we have not yet processed. We take care of
1752 // those now.
1753 int increment = 1;
1754 for (; scratch_i < scratch_cp->length(); scratch_i += increment) {
1755 switch (scratch_cp->tag_at(scratch_i).value()) {
1756 case JVM_CONSTANT_Double:
1757 case JVM_CONSTANT_Long:
1758 // double and long take two constant pool entries
1759 increment = 2;
1760 break;
1761
1762 default:
1763 increment = 1;
1764 break;
1765 }
1766
1767 int found_i =
1768 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p);
1769 if (found_i != 0) {
1770 // Found a matching entry somewhere else in *merge_cp_p so
1771 // just need a mapping entry.
1772 map_index(scratch_cp, scratch_i, found_i);
1773 continue;
1774 }
1775
1776 // No match found so we have to append this entry and any unique
1777 // referenced entries to *merge_cp_p.
1778 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p);
1779 }
1780
1781 log_debug(redefine, class, constantpool)
1782 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1783 *merge_cp_length_p, scratch_i, _index_map_count);
1784 }
1785 finalize_operands_merge(*merge_cp_p, CHECK_false);
1786
1787 return true;
1788 } // end merge_constant_pools()
1789
1790
1791 // Scoped object to clean up the constant pool(s) created for merging
1792 class MergeCPCleaner {
1793 ClassLoaderData* _loader_data;
1794 ConstantPool* _cp;
1795 ConstantPool* _scratch_cp;
1796 public:
1797 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) :
1798 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {}
1799 ~MergeCPCleaner() {
1800 _loader_data->add_to_deallocate_list(_cp);
1801 if (_scratch_cp != NULL) {
1802 _loader_data->add_to_deallocate_list(_scratch_cp);
1803 }
1804 }
1805 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; }
1806 };
1807
1808 // Merge constant pools between the_class and scratch_class and
1809 // potentially rewrite bytecodes in scratch_class to use the merged
1810 // constant pool.
1811 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite(
1812 InstanceKlass* the_class, InstanceKlass* scratch_class,
1813 TRAPS) {
1814 // worst case merged constant pool length is old and new combined
1815 int merge_cp_length = the_class->constants()->length()
1816 + scratch_class->constants()->length();
1817
1818 // Constant pools are not easily reused so we allocate a new one
1819 // each time.
1820 // merge_cp is created unsafe for concurrent GC processing. It
1821 // should be marked safe before discarding it. Even though
1822 // garbage, if it crosses a card boundary, it may be scanned
1823 // in order to find the start of the first complete object on the card.
1824 ClassLoaderData* loader_data = the_class->class_loader_data();
1825 ConstantPool* merge_cp_oop =
1826 ConstantPool::allocate(loader_data,
1827 merge_cp_length,
1828 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1829 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop);
1830
1831 HandleMark hm(THREAD); // make sure handles are cleared before
1832 // MergeCPCleaner clears out merge_cp_oop
1833 constantPoolHandle merge_cp(THREAD, merge_cp_oop);
1834
1835 // Get constants() from the old class because it could have been rewritten
1836 // while we were at a safepoint allocating a new constant pool.
1837 constantPoolHandle old_cp(THREAD, the_class->constants());
1838 constantPoolHandle scratch_cp(THREAD, scratch_class->constants());
1839
1840 // If the length changed, the class was redefined out from under us. Return
1841 // an error.
1842 if (merge_cp_length != the_class->constants()->length()
1843 + scratch_class->constants()->length()) {
1844 return JVMTI_ERROR_INTERNAL;
1845 }
1846
1847 // Update the version number of the constant pools (may keep scratch_cp)
1848 merge_cp->increment_and_save_version(old_cp->version());
1849 scratch_cp->increment_and_save_version(old_cp->version());
1850
1851 ResourceMark rm(THREAD);
1852 _index_map_count = 0;
1853 _index_map_p = new intArray(scratch_cp->length(), scratch_cp->length(), -1);
1854
1855 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands());
1856 _operands_index_map_count = 0;
1857 int operands_index_map_len = ConstantPool::operand_array_length(scratch_cp->operands());
1858 _operands_index_map_p = new intArray(operands_index_map_len, operands_index_map_len, -1);
1859
1860 // reference to the cp holder is needed for copy_operands()
1861 merge_cp->set_pool_holder(scratch_class);
1862 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp,
1863 &merge_cp_length, THREAD);
1864 merge_cp->set_pool_holder(NULL);
1865
1866 if (!result) {
1867 // The merge can fail due to memory allocation failure or due
1868 // to robustness checks.
1869 return JVMTI_ERROR_INTERNAL;
1870 }
1871
1872 // Set dynamic constants attribute from the original CP.
1873 if (old_cp->has_dynamic_constant()) {
1874 scratch_cp->set_has_dynamic_constant();
1875 }
1876 // Copy attributes from scratch_cp to merge_cp
1877 merge_cp->copy_fields(scratch_cp());
1878
1879 log_info(redefine, class, constantpool)("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count);
1880
1881 if (_index_map_count == 0) {
1882 // there is nothing to map between the new and merged constant pools
1883
1884 if (old_cp->length() == scratch_cp->length()) {
1885 // The old and new constant pools are the same length and the
1886 // index map is empty. This means that the three constant pools
1887 // are equivalent (but not the same). Unfortunately, the new
1888 // constant pool has not gone through link resolution nor have
1889 // the new class bytecodes gone through constant pool cache
1890 // rewriting so we can't use the old constant pool with the new
1891 // class.
1892
1893 // toss the merged constant pool at return
1894 } else if (old_cp->length() < scratch_cp->length()) {
1895 // The old constant pool has fewer entries than the new constant
1896 // pool and the index map is empty. This means the new constant
1897 // pool is a superset of the old constant pool. However, the old
1898 // class bytecodes have already gone through constant pool cache
1899 // rewriting so we can't use the new constant pool with the old
1900 // class.
1901
1902 // toss the merged constant pool at return
1903 } else {
1904 // The old constant pool has more entries than the new constant
1905 // pool and the index map is empty. This means that both the old
1906 // and merged constant pools are supersets of the new constant
1907 // pool.
1908
1909 // Replace the new constant pool with a shrunken copy of the
1910 // merged constant pool
1911 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1912 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1913 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1914 // It can't be cleaned up while there are handles to it.
1915 cp_cleaner.add_scratch_cp(scratch_cp());
1916 }
1917 } else {
1918 if (log_is_enabled(Trace, redefine, class, constantpool)) {
1919 // don't want to loop unless we are tracing
1920 int count = 0;
1921 for (int i = 1; i < _index_map_p->length(); i++) {
1922 int value = _index_map_p->at(i);
1923
1924 if (value != -1) {
1925 log_trace(redefine, class, constantpool)("index_map[%d]: old=%d new=%d", count, i, value);
1926 count++;
1927 }
1928 }
1929 }
1930
1931 // We have entries mapped between the new and merged constant pools
1932 // so we have to rewrite some constant pool references.
1933 if (!rewrite_cp_refs(scratch_class)) {
1934 return JVMTI_ERROR_INTERNAL;
1935 }
1936
1937 // Replace the new constant pool with a shrunken copy of the
1938 // merged constant pool so now the rewritten bytecodes have
1939 // valid references; the previous new constant pool will get
1940 // GCed.
1941 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1942 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1943 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1944 // It can't be cleaned up while there are handles to it.
1945 cp_cleaner.add_scratch_cp(scratch_cp());
1946 }
1947
1948 return JVMTI_ERROR_NONE;
1949 } // end merge_cp_and_rewrite()
1950
1951
1952 // Rewrite constant pool references in klass scratch_class.
1953 bool VM_RedefineClasses::rewrite_cp_refs(InstanceKlass* scratch_class) {
1954
1955 // rewrite constant pool references in the nest attributes:
1956 if (!rewrite_cp_refs_in_nest_attributes(scratch_class)) {
1957 // propagate failure back to caller
1958 return false;
1959 }
1960
1961 // rewrite constant pool references in the Record attribute:
1962 if (!rewrite_cp_refs_in_record_attribute(scratch_class)) {
1963 // propagate failure back to caller
1964 return false;
1965 }
1966
1967 // rewrite constant pool references in the PermittedSubclasses attribute:
1968 if (!rewrite_cp_refs_in_permitted_subclasses_attribute(scratch_class)) {
1969 // propagate failure back to caller
1970 return false;
1971 }
1972
1973 // rewrite constant pool references in the Preload attribute:
1974 if (!rewrite_cp_refs_in_preload_attribute(scratch_class)) {
1975 // propagate failure back to caller
1976 return false;
1977 }
1978
1979 // rewrite constant pool references in the methods:
1980 if (!rewrite_cp_refs_in_methods(scratch_class)) {
1981 // propagate failure back to caller
1982 return false;
1983 }
1984
1985 // rewrite constant pool references in the class_annotations:
1986 if (!rewrite_cp_refs_in_class_annotations(scratch_class)) {
1987 // propagate failure back to caller
1988 return false;
1989 }
1990
1991 // rewrite constant pool references in the fields_annotations:
1992 if (!rewrite_cp_refs_in_fields_annotations(scratch_class)) {
1993 // propagate failure back to caller
1994 return false;
1995 }
1996
1997 // rewrite constant pool references in the methods_annotations:
1998 if (!rewrite_cp_refs_in_methods_annotations(scratch_class)) {
1999 // propagate failure back to caller
2000 return false;
2001 }
2002
2003 // rewrite constant pool references in the methods_parameter_annotations:
2004 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class)) {
2005 // propagate failure back to caller
2006 return false;
2007 }
2008
2009 // rewrite constant pool references in the methods_default_annotations:
2010 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class)) {
2011 // propagate failure back to caller
2012 return false;
2013 }
2014
2015 // rewrite constant pool references in the class_type_annotations:
2016 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class)) {
2017 // propagate failure back to caller
2018 return false;
2019 }
2020
2021 // rewrite constant pool references in the fields_type_annotations:
2022 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class)) {
2023 // propagate failure back to caller
2024 return false;
2025 }
2026
2027 // rewrite constant pool references in the methods_type_annotations:
2028 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class)) {
2029 // propagate failure back to caller
2030 return false;
2031 }
2032
2033 // There can be type annotations in the Code part of a method_info attribute.
2034 // These annotations are not accessible, even by reflection.
2035 // Currently they are not even parsed by the ClassFileParser.
2036 // If runtime access is added they will also need to be rewritten.
2037
2038 // rewrite source file name index:
2039 u2 source_file_name_idx = scratch_class->source_file_name_index();
2040 if (source_file_name_idx != 0) {
2041 u2 new_source_file_name_idx = find_new_index(source_file_name_idx);
2042 if (new_source_file_name_idx != 0) {
2043 scratch_class->set_source_file_name_index(new_source_file_name_idx);
2044 }
2045 }
2046
2047 // rewrite class generic signature index:
2048 u2 generic_signature_index = scratch_class->generic_signature_index();
2049 if (generic_signature_index != 0) {
2050 u2 new_generic_signature_index = find_new_index(generic_signature_index);
2051 if (new_generic_signature_index != 0) {
2052 scratch_class->set_generic_signature_index(new_generic_signature_index);
2053 }
2054 }
2055
2056 return true;
2057 } // end rewrite_cp_refs()
2058
2059 // Rewrite constant pool references in the NestHost and NestMembers attributes.
2060 bool VM_RedefineClasses::rewrite_cp_refs_in_nest_attributes(
2061 InstanceKlass* scratch_class) {
2062
2063 u2 cp_index = scratch_class->nest_host_index();
2064 if (cp_index != 0) {
2065 scratch_class->set_nest_host_index(find_new_index(cp_index));
2066 }
2067 Array<u2>* nest_members = scratch_class->nest_members();
2068 for (int i = 0; i < nest_members->length(); i++) {
2069 u2 cp_index = nest_members->at(i);
2070 nest_members->at_put(i, find_new_index(cp_index));
2071 }
2072 return true;
2073 }
2074
2075 // Rewrite constant pool references in the Record attribute.
2076 bool VM_RedefineClasses::rewrite_cp_refs_in_record_attribute(InstanceKlass* scratch_class) {
2077 Array<RecordComponent*>* components = scratch_class->record_components();
2078 if (components != NULL) {
2079 for (int i = 0; i < components->length(); i++) {
2080 RecordComponent* component = components->at(i);
2081 u2 cp_index = component->name_index();
2082 component->set_name_index(find_new_index(cp_index));
2083 cp_index = component->descriptor_index();
2084 component->set_descriptor_index(find_new_index(cp_index));
2085 cp_index = component->generic_signature_index();
2086 if (cp_index != 0) {
2087 component->set_generic_signature_index(find_new_index(cp_index));
2088 }
2089
2090 AnnotationArray* annotations = component->annotations();
2091 if (annotations != NULL && annotations->length() != 0) {
2092 int byte_i = 0; // byte index into annotations
2093 if (!rewrite_cp_refs_in_annotations_typeArray(annotations, byte_i)) {
2094 log_debug(redefine, class, annotation)("bad record_component_annotations at %d", i);
2095 // propagate failure back to caller
2096 return false;
2097 }
2098 }
2099
2100 AnnotationArray* type_annotations = component->type_annotations();
2101 if (type_annotations != NULL && type_annotations->length() != 0) {
2102 int byte_i = 0; // byte index into annotations
2103 if (!rewrite_cp_refs_in_annotations_typeArray(type_annotations, byte_i)) {
2104 log_debug(redefine, class, annotation)("bad record_component_type_annotations at %d", i);
2105 // propagate failure back to caller
2106 return false;
2107 }
2108 }
2109 }
2110 }
2111 return true;
2112 }
2113
2114 // Rewrite constant pool references in the PermittedSubclasses attribute.
2115 bool VM_RedefineClasses::rewrite_cp_refs_in_permitted_subclasses_attribute(
2116 InstanceKlass* scratch_class) {
2117
2118 Array<u2>* permitted_subclasses = scratch_class->permitted_subclasses();
2119 assert(permitted_subclasses != NULL, "unexpected null permitted_subclasses");
2120 for (int i = 0; i < permitted_subclasses->length(); i++) {
2121 u2 cp_index = permitted_subclasses->at(i);
2122 permitted_subclasses->at_put(i, find_new_index(cp_index));
2123 }
2124 return true;
2125 }
2126
2127 // Rewrite constant pool references in the Preload attribute.
2128 bool VM_RedefineClasses::rewrite_cp_refs_in_preload_attribute(
2129 InstanceKlass* scratch_class) {
2130
2131 Array<u2>* preload_classes = scratch_class->preload_classes();
2132 assert(preload_classes != NULL, "unexpected null preload_classes");
2133 for (int i = 0; i < preload_classes->length(); i++) {
2134 u2 cp_index = preload_classes->at(i);
2135 preload_classes->at_put(i, find_new_index(cp_index));
2136 }
2137 return true;
2138 }
2139
2140 // Rewrite constant pool references in the methods.
2141 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(InstanceKlass* scratch_class) {
2142
2143 Array<Method*>* methods = scratch_class->methods();
2144
2145 if (methods == NULL || methods->length() == 0) {
2146 // no methods so nothing to do
2147 return true;
2148 }
2149
2150 JavaThread* THREAD = JavaThread::current(); // For exception macros.
2151 ExceptionMark em(THREAD);
2152
2153 // rewrite constant pool references in the methods:
2154 for (int i = methods->length() - 1; i >= 0; i--) {
2155 methodHandle method(THREAD, methods->at(i));
2156 methodHandle new_method;
2157 rewrite_cp_refs_in_method(method, &new_method, THREAD);
2158 if (!new_method.is_null()) {
2159 // the method has been replaced so save the new method version
2160 // even in the case of an exception. original method is on the
2161 // deallocation list.
2162 methods->at_put(i, new_method());
2163 }
2164 if (HAS_PENDING_EXCEPTION) {
2165 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
2166 log_info(redefine, class, load, exceptions)("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string());
2167 // Need to clear pending exception here as the super caller sets
2168 // the JVMTI_ERROR_INTERNAL if the returned value is false.
2169 CLEAR_PENDING_EXCEPTION;
2170 return false;
2171 }
2172 }
2173
2174 return true;
2175 }
2176
2177
2178 // Rewrite constant pool references in the specific method. This code
2179 // was adapted from Rewriter::rewrite_method().
2180 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method,
2181 methodHandle *new_method_p, TRAPS) {
2182
2183 *new_method_p = methodHandle(); // default is no new method
2184
2185 // We cache a pointer to the bytecodes here in code_base. If GC
2186 // moves the Method*, then the bytecodes will also move which
2187 // will likely cause a crash. We create a NoSafepointVerifier
2188 // object to detect whether we pass a possible safepoint in this
2189 // code block.
2190 NoSafepointVerifier nsv;
2191
2192 // Bytecodes and their length
2193 address code_base = method->code_base();
2194 int code_length = method->code_size();
2195
2196 int bc_length;
2197 for (int bci = 0; bci < code_length; bci += bc_length) {
2198 address bcp = code_base + bci;
2199 Bytecodes::Code c = (Bytecodes::Code)(*bcp);
2200
2201 bc_length = Bytecodes::length_for(c);
2202 if (bc_length == 0) {
2203 // More complicated bytecodes report a length of zero so
2204 // we have to try again a slightly different way.
2205 bc_length = Bytecodes::length_at(method(), bcp);
2206 }
2207
2208 assert(bc_length != 0, "impossible bytecode length");
2209
2210 switch (c) {
2211 case Bytecodes::_ldc:
2212 {
2213 int cp_index = *(bcp + 1);
2214 int new_index = find_new_index(cp_index);
2215
2216 if (StressLdcRewrite && new_index == 0) {
2217 // If we are stressing ldc -> ldc_w rewriting, then we
2218 // always need a new_index value.
2219 new_index = cp_index;
2220 }
2221 if (new_index != 0) {
2222 // the original index is mapped so we have more work to do
2223 if (!StressLdcRewrite && new_index <= max_jubyte) {
2224 // The new value can still use ldc instead of ldc_w
2225 // unless we are trying to stress ldc -> ldc_w rewriting
2226 log_trace(redefine, class, constantpool)
2227 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index);
2228 *(bcp + 1) = new_index;
2229 } else {
2230 log_trace(redefine, class, constantpool)
2231 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index);
2232 // the new value needs ldc_w instead of ldc
2233 u_char inst_buffer[4]; // max instruction size is 4 bytes
2234 bcp = (address)inst_buffer;
2235 // construct new instruction sequence
2236 *bcp = Bytecodes::_ldc_w;
2237 bcp++;
2238 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w.
2239 // See comment below for difference between put_Java_u2()
2240 // and put_native_u2().
2241 Bytes::put_Java_u2(bcp, new_index);
2242
2243 Relocator rc(method, NULL /* no RelocatorListener needed */);
2244 methodHandle m;
2245 {
2246 PauseNoSafepointVerifier pnsv(&nsv);
2247
2248 // ldc is 2 bytes and ldc_w is 3 bytes
2249 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK);
2250 }
2251
2252 // return the new method so that the caller can update
2253 // the containing class
2254 *new_method_p = method = m;
2255 // switch our bytecode processing loop from the old method
2256 // to the new method
2257 code_base = method->code_base();
2258 code_length = method->code_size();
2259 bcp = code_base + bci;
2260 c = (Bytecodes::Code)(*bcp);
2261 bc_length = Bytecodes::length_for(c);
2262 assert(bc_length != 0, "sanity check");
2263 } // end we need ldc_w instead of ldc
2264 } // end if there is a mapped index
2265 } break;
2266
2267 // these bytecodes have a two-byte constant pool index
2268 case Bytecodes::_anewarray : // fall through
2269 case Bytecodes::_checkcast : // fall through
2270 case Bytecodes::_getfield : // fall through
2271 case Bytecodes::_getstatic : // fall through
2272 case Bytecodes::_aconst_init : // fall through
2273 case Bytecodes::_withfield : // fall through
2274 case Bytecodes::_instanceof : // fall through
2275 case Bytecodes::_invokedynamic : // fall through
2276 case Bytecodes::_invokeinterface: // fall through
2277 case Bytecodes::_invokespecial : // fall through
2278 case Bytecodes::_invokestatic : // fall through
2279 case Bytecodes::_invokevirtual : // fall through
2280 case Bytecodes::_ldc_w : // fall through
2281 case Bytecodes::_ldc2_w : // fall through
2282 case Bytecodes::_multianewarray : // fall through
2283 case Bytecodes::_new : // fall through
2284 case Bytecodes::_putfield : // fall through
2285 case Bytecodes::_putstatic :
2286 {
2287 address p = bcp + 1;
2288 int cp_index = Bytes::get_Java_u2(p);
2289 int new_index = find_new_index(cp_index);
2290 if (new_index != 0) {
2291 // the original index is mapped so update w/ new value
2292 log_trace(redefine, class, constantpool)
2293 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),p2i(bcp), cp_index, new_index);
2294 // Rewriter::rewrite_method() uses put_native_u2() in this
2295 // situation because it is reusing the constant pool index
2296 // location for a native index into the ConstantPoolCache.
2297 // Since we are updating the constant pool index prior to
2298 // verification and ConstantPoolCache initialization, we
2299 // need to keep the new index in Java byte order.
2300 Bytes::put_Java_u2(p, new_index);
2301 }
2302 } break;
2303 default:
2304 break;
2305 }
2306 } // end for each bytecode
2307 } // end rewrite_cp_refs_in_method()
2308
2309
2310 // Rewrite constant pool references in the class_annotations field.
2311 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(InstanceKlass* scratch_class) {
2312
2313 AnnotationArray* class_annotations = scratch_class->class_annotations();
2314 if (class_annotations == NULL || class_annotations->length() == 0) {
2315 // no class_annotations so nothing to do
2316 return true;
2317 }
2318
2319 log_debug(redefine, class, annotation)("class_annotations length=%d", class_annotations->length());
2320
2321 int byte_i = 0; // byte index into class_annotations
2322 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i);
2323 }
2324
2325
2326 // Rewrite constant pool references in an annotations typeArray. This
2327 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute
2328 // that is described in section 4.8.15 of the 2nd-edition of the VM spec:
2329 //
2330 // annotations_typeArray {
2331 // u2 num_annotations;
2332 // annotation annotations[num_annotations];
2333 // }
2334 //
2335 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray(
2336 AnnotationArray* annotations_typeArray, int &byte_i_ref) {
2337
2338 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2339 // not enough room for num_annotations field
2340 log_debug(redefine, class, annotation)("length() is too small for num_annotations field");
2341 return false;
2342 }
2343
2344 u2 num_annotations = Bytes::get_Java_u2((address)
2345 annotations_typeArray->adr_at(byte_i_ref));
2346 byte_i_ref += 2;
2347
2348 log_debug(redefine, class, annotation)("num_annotations=%d", num_annotations);
2349
2350 int calc_num_annotations = 0;
2351 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
2352 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, byte_i_ref)) {
2353 log_debug(redefine, class, annotation)("bad annotation_struct at %d", calc_num_annotations);
2354 // propagate failure back to caller
2355 return false;
2356 }
2357 }
2358 assert(num_annotations == calc_num_annotations, "sanity check");
2359
2360 return true;
2361 } // end rewrite_cp_refs_in_annotations_typeArray()
2362
2363
2364 // Rewrite constant pool references in the annotation struct portion of
2365 // an annotations_typeArray. This "structure" is from section 4.8.15 of
2366 // the 2nd-edition of the VM spec:
2367 //
2368 // struct annotation {
2369 // u2 type_index;
2370 // u2 num_element_value_pairs;
2371 // {
2372 // u2 element_name_index;
2373 // element_value value;
2374 // } element_value_pairs[num_element_value_pairs];
2375 // }
2376 //
2377 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct(
2378 AnnotationArray* annotations_typeArray, int &byte_i_ref) {
2379 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) {
2380 // not enough room for smallest annotation_struct
2381 log_debug(redefine, class, annotation)("length() is too small for annotation_struct");
2382 return false;
2383 }
2384
2385 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray,
2386 byte_i_ref, "type_index");
2387
2388 u2 num_element_value_pairs = Bytes::get_Java_u2((address)
2389 annotations_typeArray->adr_at(byte_i_ref));
2390 byte_i_ref += 2;
2391
2392 log_debug(redefine, class, annotation)
2393 ("type_index=%d num_element_value_pairs=%d", type_index, num_element_value_pairs);
2394
2395 int calc_num_element_value_pairs = 0;
2396 for (; calc_num_element_value_pairs < num_element_value_pairs;
2397 calc_num_element_value_pairs++) {
2398 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2399 // not enough room for another element_name_index, let alone
2400 // the rest of another component
2401 log_debug(redefine, class, annotation)("length() is too small for element_name_index");
2402 return false;
2403 }
2404
2405 u2 element_name_index = rewrite_cp_ref_in_annotation_data(
2406 annotations_typeArray, byte_i_ref,
2407 "element_name_index");
2408
2409 log_debug(redefine, class, annotation)("element_name_index=%d", element_name_index);
2410
2411 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, byte_i_ref)) {
2412 log_debug(redefine, class, annotation)("bad element_value at %d", calc_num_element_value_pairs);
2413 // propagate failure back to caller
2414 return false;
2415 }
2416 } // end for each component
2417 assert(num_element_value_pairs == calc_num_element_value_pairs,
2418 "sanity check");
2419
2420 return true;
2421 } // end rewrite_cp_refs_in_annotation_struct()
2422
2423
2424 // Rewrite a constant pool reference at the current position in
2425 // annotations_typeArray if needed. Returns the original constant
2426 // pool reference if a rewrite was not needed or the new constant
2427 // pool reference if a rewrite was needed.
2428 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data(
2429 AnnotationArray* annotations_typeArray, int &byte_i_ref,
2430 const char * trace_mesg) {
2431
2432 address cp_index_addr = (address)
2433 annotations_typeArray->adr_at(byte_i_ref);
2434 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr);
2435 u2 new_cp_index = find_new_index(old_cp_index);
2436 if (new_cp_index != 0) {
2437 log_debug(redefine, class, annotation)("mapped old %s=%d", trace_mesg, old_cp_index);
2438 Bytes::put_Java_u2(cp_index_addr, new_cp_index);
2439 old_cp_index = new_cp_index;
2440 }
2441 byte_i_ref += 2;
2442 return old_cp_index;
2443 }
2444
2445
2446 // Rewrite constant pool references in the element_value portion of an
2447 // annotations_typeArray. This "structure" is from section 4.8.15.1 of
2448 // the 2nd-edition of the VM spec:
2449 //
2450 // struct element_value {
2451 // u1 tag;
2452 // union {
2453 // u2 const_value_index;
2454 // {
2455 // u2 type_name_index;
2456 // u2 const_name_index;
2457 // } enum_const_value;
2458 // u2 class_info_index;
2459 // annotation annotation_value;
2460 // struct {
2461 // u2 num_values;
2462 // element_value values[num_values];
2463 // } array_value;
2464 // } value;
2465 // }
2466 //
2467 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value(
2468 AnnotationArray* annotations_typeArray, int &byte_i_ref) {
2469
2470 if ((byte_i_ref + 1) > annotations_typeArray->length()) {
2471 // not enough room for a tag let alone the rest of an element_value
2472 log_debug(redefine, class, annotation)("length() is too small for a tag");
2473 return false;
2474 }
2475
2476 u1 tag = annotations_typeArray->at(byte_i_ref);
2477 byte_i_ref++;
2478 log_debug(redefine, class, annotation)("tag='%c'", tag);
2479
2480 switch (tag) {
2481 // These BaseType tag values are from Table 4.2 in VM spec:
2482 case JVM_SIGNATURE_BYTE:
2483 case JVM_SIGNATURE_CHAR:
2484 case JVM_SIGNATURE_DOUBLE:
2485 case JVM_SIGNATURE_FLOAT:
2486 case JVM_SIGNATURE_INT:
2487 case JVM_SIGNATURE_LONG:
2488 case JVM_SIGNATURE_SHORT:
2489 case JVM_SIGNATURE_BOOLEAN:
2490
2491 // The remaining tag values are from Table 4.8 in the 2nd-edition of
2492 // the VM spec:
2493 case 's':
2494 {
2495 // For the above tag values (including the BaseType values),
2496 // value.const_value_index is right union field.
2497
2498 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2499 // not enough room for a const_value_index
2500 log_debug(redefine, class, annotation)("length() is too small for a const_value_index");
2501 return false;
2502 }
2503
2504 u2 const_value_index = rewrite_cp_ref_in_annotation_data(
2505 annotations_typeArray, byte_i_ref,
2506 "const_value_index");
2507
2508 log_debug(redefine, class, annotation)("const_value_index=%d", const_value_index);
2509 } break;
2510
2511 case 'e':
2512 {
2513 // for the above tag value, value.enum_const_value is right union field
2514
2515 if ((byte_i_ref + 4) > annotations_typeArray->length()) {
2516 // not enough room for a enum_const_value
2517 log_debug(redefine, class, annotation)("length() is too small for a enum_const_value");
2518 return false;
2519 }
2520
2521 u2 type_name_index = rewrite_cp_ref_in_annotation_data(
2522 annotations_typeArray, byte_i_ref,
2523 "type_name_index");
2524
2525 u2 const_name_index = rewrite_cp_ref_in_annotation_data(
2526 annotations_typeArray, byte_i_ref,
2527 "const_name_index");
2528
2529 log_debug(redefine, class, annotation)
2530 ("type_name_index=%d const_name_index=%d", type_name_index, const_name_index);
2531 } break;
2532
2533 case 'c':
2534 {
2535 // for the above tag value, value.class_info_index is right union field
2536
2537 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2538 // not enough room for a class_info_index
2539 log_debug(redefine, class, annotation)("length() is too small for a class_info_index");
2540 return false;
2541 }
2542
2543 u2 class_info_index = rewrite_cp_ref_in_annotation_data(
2544 annotations_typeArray, byte_i_ref,
2545 "class_info_index");
2546
2547 log_debug(redefine, class, annotation)("class_info_index=%d", class_info_index);
2548 } break;
2549
2550 case '@':
2551 // For the above tag value, value.attr_value is the right union
2552 // field. This is a nested annotation.
2553 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, byte_i_ref)) {
2554 // propagate failure back to caller
2555 return false;
2556 }
2557 break;
2558
2559 case JVM_SIGNATURE_ARRAY:
2560 {
2561 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2562 // not enough room for a num_values field
2563 log_debug(redefine, class, annotation)("length() is too small for a num_values field");
2564 return false;
2565 }
2566
2567 // For the above tag value, value.array_value is the right union
2568 // field. This is an array of nested element_value.
2569 u2 num_values = Bytes::get_Java_u2((address)
2570 annotations_typeArray->adr_at(byte_i_ref));
2571 byte_i_ref += 2;
2572 log_debug(redefine, class, annotation)("num_values=%d", num_values);
2573
2574 int calc_num_values = 0;
2575 for (; calc_num_values < num_values; calc_num_values++) {
2576 if (!rewrite_cp_refs_in_element_value(annotations_typeArray, byte_i_ref)) {
2577 log_debug(redefine, class, annotation)("bad nested element_value at %d", calc_num_values);
2578 // propagate failure back to caller
2579 return false;
2580 }
2581 }
2582 assert(num_values == calc_num_values, "sanity check");
2583 } break;
2584
2585 default:
2586 log_debug(redefine, class, annotation)("bad tag=0x%x", tag);
2587 return false;
2588 } // end decode tag field
2589
2590 return true;
2591 } // end rewrite_cp_refs_in_element_value()
2592
2593
2594 // Rewrite constant pool references in a fields_annotations field.
2595 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations(
2596 InstanceKlass* scratch_class) {
2597
2598 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations();
2599
2600 if (fields_annotations == NULL || fields_annotations->length() == 0) {
2601 // no fields_annotations so nothing to do
2602 return true;
2603 }
2604
2605 log_debug(redefine, class, annotation)("fields_annotations length=%d", fields_annotations->length());
2606
2607 for (int i = 0; i < fields_annotations->length(); i++) {
2608 AnnotationArray* field_annotations = fields_annotations->at(i);
2609 if (field_annotations == NULL || field_annotations->length() == 0) {
2610 // this field does not have any annotations so skip it
2611 continue;
2612 }
2613
2614 int byte_i = 0; // byte index into field_annotations
2615 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i)) {
2616 log_debug(redefine, class, annotation)("bad field_annotations at %d", i);
2617 // propagate failure back to caller
2618 return false;
2619 }
2620 }
2621
2622 return true;
2623 } // end rewrite_cp_refs_in_fields_annotations()
2624
2625
2626 // Rewrite constant pool references in a methods_annotations field.
2627 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations(
2628 InstanceKlass* scratch_class) {
2629
2630 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2631 Method* m = scratch_class->methods()->at(i);
2632 AnnotationArray* method_annotations = m->constMethod()->method_annotations();
2633
2634 if (method_annotations == NULL || method_annotations->length() == 0) {
2635 // this method does not have any annotations so skip it
2636 continue;
2637 }
2638
2639 int byte_i = 0; // byte index into method_annotations
2640 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i)) {
2641 log_debug(redefine, class, annotation)("bad method_annotations at %d", i);
2642 // propagate failure back to caller
2643 return false;
2644 }
2645 }
2646
2647 return true;
2648 } // end rewrite_cp_refs_in_methods_annotations()
2649
2650
2651 // Rewrite constant pool references in a methods_parameter_annotations
2652 // field. This "structure" is adapted from the
2653 // RuntimeVisibleParameterAnnotations_attribute described in section
2654 // 4.8.17 of the 2nd-edition of the VM spec:
2655 //
2656 // methods_parameter_annotations_typeArray {
2657 // u1 num_parameters;
2658 // {
2659 // u2 num_annotations;
2660 // annotation annotations[num_annotations];
2661 // } parameter_annotations[num_parameters];
2662 // }
2663 //
2664 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations(
2665 InstanceKlass* scratch_class) {
2666
2667 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2668 Method* m = scratch_class->methods()->at(i);
2669 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations();
2670 if (method_parameter_annotations == NULL
2671 || method_parameter_annotations->length() == 0) {
2672 // this method does not have any parameter annotations so skip it
2673 continue;
2674 }
2675
2676 if (method_parameter_annotations->length() < 1) {
2677 // not enough room for a num_parameters field
2678 log_debug(redefine, class, annotation)("length() is too small for a num_parameters field at %d", i);
2679 return false;
2680 }
2681
2682 int byte_i = 0; // byte index into method_parameter_annotations
2683
2684 u1 num_parameters = method_parameter_annotations->at(byte_i);
2685 byte_i++;
2686
2687 log_debug(redefine, class, annotation)("num_parameters=%d", num_parameters);
2688
2689 int calc_num_parameters = 0;
2690 for (; calc_num_parameters < num_parameters; calc_num_parameters++) {
2691 if (!rewrite_cp_refs_in_annotations_typeArray(method_parameter_annotations, byte_i)) {
2692 log_debug(redefine, class, annotation)("bad method_parameter_annotations at %d", calc_num_parameters);
2693 // propagate failure back to caller
2694 return false;
2695 }
2696 }
2697 assert(num_parameters == calc_num_parameters, "sanity check");
2698 }
2699
2700 return true;
2701 } // end rewrite_cp_refs_in_methods_parameter_annotations()
2702
2703
2704 // Rewrite constant pool references in a methods_default_annotations
2705 // field. This "structure" is adapted from the AnnotationDefault_attribute
2706 // that is described in section 4.8.19 of the 2nd-edition of the VM spec:
2707 //
2708 // methods_default_annotations_typeArray {
2709 // element_value default_value;
2710 // }
2711 //
2712 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations(
2713 InstanceKlass* scratch_class) {
2714
2715 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2716 Method* m = scratch_class->methods()->at(i);
2717 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations();
2718 if (method_default_annotations == NULL
2719 || method_default_annotations->length() == 0) {
2720 // this method does not have any default annotations so skip it
2721 continue;
2722 }
2723
2724 int byte_i = 0; // byte index into method_default_annotations
2725
2726 if (!rewrite_cp_refs_in_element_value(
2727 method_default_annotations, byte_i)) {
2728 log_debug(redefine, class, annotation)("bad default element_value at %d", i);
2729 // propagate failure back to caller
2730 return false;
2731 }
2732 }
2733
2734 return true;
2735 } // end rewrite_cp_refs_in_methods_default_annotations()
2736
2737
2738 // Rewrite constant pool references in a class_type_annotations field.
2739 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations(
2740 InstanceKlass* scratch_class) {
2741
2742 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations();
2743 if (class_type_annotations == NULL || class_type_annotations->length() == 0) {
2744 // no class_type_annotations so nothing to do
2745 return true;
2746 }
2747
2748 log_debug(redefine, class, annotation)("class_type_annotations length=%d", class_type_annotations->length());
2749
2750 int byte_i = 0; // byte index into class_type_annotations
2751 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations,
2752 byte_i, "ClassFile");
2753 } // end rewrite_cp_refs_in_class_type_annotations()
2754
2755
2756 // Rewrite constant pool references in a fields_type_annotations field.
2757 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations(InstanceKlass* scratch_class) {
2758
2759 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations();
2760 if (fields_type_annotations == NULL || fields_type_annotations->length() == 0) {
2761 // no fields_type_annotations so nothing to do
2762 return true;
2763 }
2764
2765 log_debug(redefine, class, annotation)("fields_type_annotations length=%d", fields_type_annotations->length());
2766
2767 for (int i = 0; i < fields_type_annotations->length(); i++) {
2768 AnnotationArray* field_type_annotations = fields_type_annotations->at(i);
2769 if (field_type_annotations == NULL || field_type_annotations->length() == 0) {
2770 // this field does not have any annotations so skip it
2771 continue;
2772 }
2773
2774 int byte_i = 0; // byte index into field_type_annotations
2775 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations,
2776 byte_i, "field_info")) {
2777 log_debug(redefine, class, annotation)("bad field_type_annotations at %d", i);
2778 // propagate failure back to caller
2779 return false;
2780 }
2781 }
2782
2783 return true;
2784 } // end rewrite_cp_refs_in_fields_type_annotations()
2785
2786
2787 // Rewrite constant pool references in a methods_type_annotations field.
2788 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations(
2789 InstanceKlass* scratch_class) {
2790
2791 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2792 Method* m = scratch_class->methods()->at(i);
2793 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations();
2794
2795 if (method_type_annotations == NULL || method_type_annotations->length() == 0) {
2796 // this method does not have any annotations so skip it
2797 continue;
2798 }
2799
2800 log_debug(redefine, class, annotation)("methods type_annotations length=%d", method_type_annotations->length());
2801
2802 int byte_i = 0; // byte index into method_type_annotations
2803 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations,
2804 byte_i, "method_info")) {
2805 log_debug(redefine, class, annotation)("bad method_type_annotations at %d", i);
2806 // propagate failure back to caller
2807 return false;
2808 }
2809 }
2810
2811 return true;
2812 } // end rewrite_cp_refs_in_methods_type_annotations()
2813
2814
2815 // Rewrite constant pool references in a type_annotations
2816 // field. This "structure" is adapted from the
2817 // RuntimeVisibleTypeAnnotations_attribute described in
2818 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2819 //
2820 // type_annotations_typeArray {
2821 // u2 num_annotations;
2822 // type_annotation annotations[num_annotations];
2823 // }
2824 //
2825 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray(
2826 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2827 const char * location_mesg) {
2828
2829 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2830 // not enough room for num_annotations field
2831 log_debug(redefine, class, annotation)("length() is too small for num_annotations field");
2832 return false;
2833 }
2834
2835 u2 num_annotations = Bytes::get_Java_u2((address)
2836 type_annotations_typeArray->adr_at(byte_i_ref));
2837 byte_i_ref += 2;
2838
2839 log_debug(redefine, class, annotation)("num_type_annotations=%d", num_annotations);
2840
2841 int calc_num_annotations = 0;
2842 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
2843 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray,
2844 byte_i_ref, location_mesg)) {
2845 log_debug(redefine, class, annotation)("bad type_annotation_struct at %d", calc_num_annotations);
2846 // propagate failure back to caller
2847 return false;
2848 }
2849 }
2850 assert(num_annotations == calc_num_annotations, "sanity check");
2851
2852 if (byte_i_ref != type_annotations_typeArray->length()) {
2853 log_debug(redefine, class, annotation)
2854 ("read wrong amount of bytes at end of processing type_annotations_typeArray (%d of %d bytes were read)",
2855 byte_i_ref, type_annotations_typeArray->length());
2856 return false;
2857 }
2858
2859 return true;
2860 } // end rewrite_cp_refs_in_type_annotations_typeArray()
2861
2862
2863 // Rewrite constant pool references in a type_annotation
2864 // field. This "structure" is adapted from the
2865 // RuntimeVisibleTypeAnnotations_attribute described in
2866 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2867 //
2868 // type_annotation {
2869 // u1 target_type;
2870 // union {
2871 // type_parameter_target;
2872 // supertype_target;
2873 // type_parameter_bound_target;
2874 // empty_target;
2875 // method_formal_parameter_target;
2876 // throws_target;
2877 // localvar_target;
2878 // catch_target;
2879 // offset_target;
2880 // type_argument_target;
2881 // } target_info;
2882 // type_path target_path;
2883 // annotation anno;
2884 // }
2885 //
2886 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct(
2887 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2888 const char * location_mesg) {
2889
2890 if (!skip_type_annotation_target(type_annotations_typeArray,
2891 byte_i_ref, location_mesg)) {
2892 return false;
2893 }
2894
2895 if (!skip_type_annotation_type_path(type_annotations_typeArray, byte_i_ref)) {
2896 return false;
2897 }
2898
2899 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray, byte_i_ref)) {
2900 return false;
2901 }
2902
2903 return true;
2904 } // end rewrite_cp_refs_in_type_annotation_struct()
2905
2906
2907 // Read, verify and skip over the target_type and target_info part
2908 // so that rewriting can continue in the later parts of the struct.
2909 //
2910 // u1 target_type;
2911 // union {
2912 // type_parameter_target;
2913 // supertype_target;
2914 // type_parameter_bound_target;
2915 // empty_target;
2916 // method_formal_parameter_target;
2917 // throws_target;
2918 // localvar_target;
2919 // catch_target;
2920 // offset_target;
2921 // type_argument_target;
2922 // } target_info;
2923 //
2924 bool VM_RedefineClasses::skip_type_annotation_target(
2925 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2926 const char * location_mesg) {
2927
2928 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2929 // not enough room for a target_type let alone the rest of a type_annotation
2930 log_debug(redefine, class, annotation)("length() is too small for a target_type");
2931 return false;
2932 }
2933
2934 u1 target_type = type_annotations_typeArray->at(byte_i_ref);
2935 byte_i_ref += 1;
2936 log_debug(redefine, class, annotation)("target_type=0x%.2x", target_type);
2937 log_debug(redefine, class, annotation)("location=%s", location_mesg);
2938
2939 // Skip over target_info
2940 switch (target_type) {
2941 case 0x00:
2942 // kind: type parameter declaration of generic class or interface
2943 // location: ClassFile
2944 case 0x01:
2945 // kind: type parameter declaration of generic method or constructor
2946 // location: method_info
2947
2948 {
2949 // struct:
2950 // type_parameter_target {
2951 // u1 type_parameter_index;
2952 // }
2953 //
2954 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2955 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_target");
2956 return false;
2957 }
2958
2959 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2960 byte_i_ref += 1;
2961
2962 log_debug(redefine, class, annotation)("type_parameter_target: type_parameter_index=%d", type_parameter_index);
2963 } break;
2964
2965 case 0x10:
2966 // kind: type in extends clause of class or interface declaration
2967 // or in implements clause of interface declaration
2968 // location: ClassFile
2969
2970 {
2971 // struct:
2972 // supertype_target {
2973 // u2 supertype_index;
2974 // }
2975 //
2976 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2977 log_debug(redefine, class, annotation)("length() is too small for a supertype_target");
2978 return false;
2979 }
2980
2981 u2 supertype_index = Bytes::get_Java_u2((address)
2982 type_annotations_typeArray->adr_at(byte_i_ref));
2983 byte_i_ref += 2;
2984
2985 log_debug(redefine, class, annotation)("supertype_target: supertype_index=%d", supertype_index);
2986 } break;
2987
2988 case 0x11:
2989 // kind: type in bound of type parameter declaration of generic class or interface
2990 // location: ClassFile
2991 case 0x12:
2992 // kind: type in bound of type parameter declaration of generic method or constructor
2993 // location: method_info
2994
2995 {
2996 // struct:
2997 // type_parameter_bound_target {
2998 // u1 type_parameter_index;
2999 // u1 bound_index;
3000 // }
3001 //
3002 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
3003 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_bound_target");
3004 return false;
3005 }
3006
3007 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
3008 byte_i_ref += 1;
3009 u1 bound_index = type_annotations_typeArray->at(byte_i_ref);
3010 byte_i_ref += 1;
3011
3012 log_debug(redefine, class, annotation)
3013 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d", type_parameter_index, bound_index);
3014 } break;
3015
3016 case 0x13:
3017 // kind: type in field declaration
3018 // location: field_info
3019 case 0x14:
3020 // kind: return type of method, or type of newly constructed object
3021 // location: method_info
3022 case 0x15:
3023 // kind: receiver type of method or constructor
3024 // location: method_info
3025
3026 {
3027 // struct:
3028 // empty_target {
3029 // }
3030 //
3031 log_debug(redefine, class, annotation)("empty_target");
3032 } break;
3033
3034 case 0x16:
3035 // kind: type in formal parameter declaration of method, constructor, or lambda expression
3036 // location: method_info
3037
3038 {
3039 // struct:
3040 // formal_parameter_target {
3041 // u1 formal_parameter_index;
3042 // }
3043 //
3044 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
3045 log_debug(redefine, class, annotation)("length() is too small for a formal_parameter_target");
3046 return false;
3047 }
3048
3049 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref);
3050 byte_i_ref += 1;
3051
3052 log_debug(redefine, class, annotation)
3053 ("formal_parameter_target: formal_parameter_index=%d", formal_parameter_index);
3054 } break;
3055
3056 case 0x17:
3057 // kind: type in throws clause of method or constructor
3058 // location: method_info
3059
3060 {
3061 // struct:
3062 // throws_target {
3063 // u2 throws_type_index
3064 // }
3065 //
3066 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
3067 log_debug(redefine, class, annotation)("length() is too small for a throws_target");
3068 return false;
3069 }
3070
3071 u2 throws_type_index = Bytes::get_Java_u2((address)
3072 type_annotations_typeArray->adr_at(byte_i_ref));
3073 byte_i_ref += 2;
3074
3075 log_debug(redefine, class, annotation)("throws_target: throws_type_index=%d", throws_type_index);
3076 } break;
3077
3078 case 0x40:
3079 // kind: type in local variable declaration
3080 // location: Code
3081 case 0x41:
3082 // kind: type in resource variable declaration
3083 // location: Code
3084
3085 {
3086 // struct:
3087 // localvar_target {
3088 // u2 table_length;
3089 // struct {
3090 // u2 start_pc;
3091 // u2 length;
3092 // u2 index;
3093 // } table[table_length];
3094 // }
3095 //
3096 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
3097 // not enough room for a table_length let alone the rest of a localvar_target
3098 log_debug(redefine, class, annotation)("length() is too small for a localvar_target table_length");
3099 return false;
3100 }
3101
3102 u2 table_length = Bytes::get_Java_u2((address)
3103 type_annotations_typeArray->adr_at(byte_i_ref));
3104 byte_i_ref += 2;
3105
3106 log_debug(redefine, class, annotation)("localvar_target: table_length=%d", table_length);
3107
3108 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry
3109 int table_size = table_length * table_struct_size;
3110
3111 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) {
3112 // not enough room for a table
3113 log_debug(redefine, class, annotation)("length() is too small for a table array of length %d", table_length);
3114 return false;
3115 }
3116
3117 // Skip over table
3118 byte_i_ref += table_size;
3119 } break;
3120
3121 case 0x42:
3122 // kind: type in exception parameter declaration
3123 // location: Code
3124
3125 {
3126 // struct:
3127 // catch_target {
3128 // u2 exception_table_index;
3129 // }
3130 //
3131 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
3132 log_debug(redefine, class, annotation)("length() is too small for a catch_target");
3133 return false;
3134 }
3135
3136 u2 exception_table_index = Bytes::get_Java_u2((address)
3137 type_annotations_typeArray->adr_at(byte_i_ref));
3138 byte_i_ref += 2;
3139
3140 log_debug(redefine, class, annotation)("catch_target: exception_table_index=%d", exception_table_index);
3141 } break;
3142
3143 case 0x43:
3144 // kind: type in instanceof expression
3145 // location: Code
3146 case 0x44:
3147 // kind: type in new expression
3148 // location: Code
3149 case 0x45:
3150 // kind: type in method reference expression using ::new
3151 // location: Code
3152 case 0x46:
3153 // kind: type in method reference expression using ::Identifier
3154 // location: Code
3155
3156 {
3157 // struct:
3158 // offset_target {
3159 // u2 offset;
3160 // }
3161 //
3162 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
3163 log_debug(redefine, class, annotation)("length() is too small for a offset_target");
3164 return false;
3165 }
3166
3167 u2 offset = Bytes::get_Java_u2((address)
3168 type_annotations_typeArray->adr_at(byte_i_ref));
3169 byte_i_ref += 2;
3170
3171 log_debug(redefine, class, annotation)("offset_target: offset=%d", offset);
3172 } break;
3173
3174 case 0x47:
3175 // kind: type in cast expression
3176 // location: Code
3177 case 0x48:
3178 // kind: type argument for generic constructor in new expression or
3179 // explicit constructor invocation statement
3180 // location: Code
3181 case 0x49:
3182 // kind: type argument for generic method in method invocation expression
3183 // location: Code
3184 case 0x4A:
3185 // kind: type argument for generic constructor in method reference expression using ::new
3186 // location: Code
3187 case 0x4B:
3188 // kind: type argument for generic method in method reference expression using ::Identifier
3189 // location: Code
3190
3191 {
3192 // struct:
3193 // type_argument_target {
3194 // u2 offset;
3195 // u1 type_argument_index;
3196 // }
3197 //
3198 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) {
3199 log_debug(redefine, class, annotation)("length() is too small for a type_argument_target");
3200 return false;
3201 }
3202
3203 u2 offset = Bytes::get_Java_u2((address)
3204 type_annotations_typeArray->adr_at(byte_i_ref));
3205 byte_i_ref += 2;
3206 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
3207 byte_i_ref += 1;
3208
3209 log_debug(redefine, class, annotation)
3210 ("type_argument_target: offset=%d, type_argument_index=%d", offset, type_argument_index);
3211 } break;
3212
3213 default:
3214 log_debug(redefine, class, annotation)("unknown target_type");
3215 #ifdef ASSERT
3216 ShouldNotReachHere();
3217 #endif
3218 return false;
3219 }
3220
3221 return true;
3222 } // end skip_type_annotation_target()
3223
3224
3225 // Read, verify and skip over the type_path part so that rewriting
3226 // can continue in the later parts of the struct.
3227 //
3228 // type_path {
3229 // u1 path_length;
3230 // {
3231 // u1 type_path_kind;
3232 // u1 type_argument_index;
3233 // } path[path_length];
3234 // }
3235 //
3236 bool VM_RedefineClasses::skip_type_annotation_type_path(
3237 AnnotationArray* type_annotations_typeArray, int &byte_i_ref) {
3238
3239 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
3240 // not enough room for a path_length let alone the rest of the type_path
3241 log_debug(redefine, class, annotation)("length() is too small for a type_path");
3242 return false;
3243 }
3244
3245 u1 path_length = type_annotations_typeArray->at(byte_i_ref);
3246 byte_i_ref += 1;
3247
3248 log_debug(redefine, class, annotation)("type_path: path_length=%d", path_length);
3249
3250 int calc_path_length = 0;
3251 for (; calc_path_length < path_length; calc_path_length++) {
3252 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) {
3253 // not enough room for a path
3254 log_debug(redefine, class, annotation)
3255 ("length() is too small for path entry %d of %d", calc_path_length, path_length);
3256 return false;
3257 }
3258
3259 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref);
3260 byte_i_ref += 1;
3261 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
3262 byte_i_ref += 1;
3263
3264 log_debug(redefine, class, annotation)
3265 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d",
3266 calc_path_length, type_path_kind, type_argument_index);
3267
3268 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) {
3269 // not enough room for a path
3270 log_debug(redefine, class, annotation)("inconsistent type_path values");
3271 return false;
3272 }
3273 }
3274 assert(path_length == calc_path_length, "sanity check");
3275
3276 return true;
3277 } // end skip_type_annotation_type_path()
3278
3279
3280 // Rewrite constant pool references in the method's stackmap table.
3281 // These "structures" are adapted from the StackMapTable_attribute that
3282 // is described in section 4.8.4 of the 6.0 version of the VM spec
3283 // (dated 2005.10.26):
3284 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
3285 //
3286 // stack_map {
3287 // u2 number_of_entries;
3288 // stack_map_frame entries[number_of_entries];
3289 // }
3290 //
3291 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table(
3292 const methodHandle& method) {
3293
3294 if (!method->has_stackmap_table()) {
3295 return;
3296 }
3297
3298 AnnotationArray* stackmap_data = method->stackmap_data();
3299 address stackmap_p = (address)stackmap_data->adr_at(0);
3300 address stackmap_end = stackmap_p + stackmap_data->length();
3301
3302 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries");
3303 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p);
3304 stackmap_p += 2;
3305
3306 log_debug(redefine, class, stackmap)("number_of_entries=%u", number_of_entries);
3307
3308 // walk through each stack_map_frame
3309 u2 calc_number_of_entries = 0;
3310 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) {
3311 // The stack_map_frame structure is a u1 frame_type followed by
3312 // 0 or more bytes of data:
3313 //
3314 // union stack_map_frame {
3315 // same_frame;
3316 // same_locals_1_stack_item_frame;
3317 // same_locals_1_stack_item_frame_extended;
3318 // chop_frame;
3319 // same_frame_extended;
3320 // append_frame;
3321 // full_frame;
3322 // }
3323
3324 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type");
3325 u1 frame_type = *stackmap_p;
3326 stackmap_p++;
3327
3328 // same_frame {
3329 // u1 frame_type = SAME; /* 0-63 */
3330 // }
3331 if (frame_type <= 63) {
3332 // nothing more to do for same_frame
3333 }
3334
3335 // same_locals_1_stack_item_frame {
3336 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */
3337 // verification_type_info stack[1];
3338 // }
3339 else if (frame_type >= 64 && frame_type <= 127) {
3340 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3341 calc_number_of_entries, frame_type);
3342 }
3343
3344 // reserved for future use
3345 else if (frame_type >= 128 && frame_type <= 246) {
3346 // nothing more to do for reserved frame_types
3347 }
3348
3349 // same_locals_1_stack_item_frame_extended {
3350 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */
3351 // u2 offset_delta;
3352 // verification_type_info stack[1];
3353 // }
3354 else if (frame_type == 247) {
3355 stackmap_p += 2;
3356 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3357 calc_number_of_entries, frame_type);
3358 }
3359
3360 // chop_frame {
3361 // u1 frame_type = CHOP; /* 248-250 */
3362 // u2 offset_delta;
3363 // }
3364 else if (frame_type >= 248 && frame_type <= 250) {
3365 stackmap_p += 2;
3366 }
3367
3368 // same_frame_extended {
3369 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/
3370 // u2 offset_delta;
3371 // }
3372 else if (frame_type == 251) {
3373 stackmap_p += 2;
3374 }
3375
3376 // append_frame {
3377 // u1 frame_type = APPEND; /* 252-254 */
3378 // u2 offset_delta;
3379 // verification_type_info locals[frame_type - 251];
3380 // }
3381 else if (frame_type >= 252 && frame_type <= 254) {
3382 assert(stackmap_p + 2 <= stackmap_end,
3383 "no room for offset_delta");
3384 stackmap_p += 2;
3385 u1 len = frame_type - 251;
3386 for (u1 i = 0; i < len; i++) {
3387 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3388 calc_number_of_entries, frame_type);
3389 }
3390 }
3391
3392 // full_frame {
3393 // u1 frame_type = FULL_FRAME; /* 255 */
3394 // u2 offset_delta;
3395 // u2 number_of_locals;
3396 // verification_type_info locals[number_of_locals];
3397 // u2 number_of_stack_items;
3398 // verification_type_info stack[number_of_stack_items];
3399 // }
3400 else if (frame_type == 255) {
3401 assert(stackmap_p + 2 + 2 <= stackmap_end,
3402 "no room for smallest full_frame");
3403 stackmap_p += 2;
3404
3405 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p);
3406 stackmap_p += 2;
3407
3408 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) {
3409 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3410 calc_number_of_entries, frame_type);
3411 }
3412
3413 // Use the largest size for the number_of_stack_items, but only get
3414 // the right number of bytes.
3415 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p);
3416 stackmap_p += 2;
3417
3418 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) {
3419 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3420 calc_number_of_entries, frame_type);
3421 }
3422 }
3423 } // end while there is a stack_map_frame
3424 assert(number_of_entries == calc_number_of_entries, "sanity check");
3425 } // end rewrite_cp_refs_in_stack_map_table()
3426
3427
3428 // Rewrite constant pool references in the verification type info
3429 // portion of the method's stackmap table. These "structures" are
3430 // adapted from the StackMapTable_attribute that is described in
3431 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26):
3432 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
3433 //
3434 // The verification_type_info structure is a u1 tag followed by 0 or
3435 // more bytes of data:
3436 //
3437 // union verification_type_info {
3438 // Top_variable_info;
3439 // Integer_variable_info;
3440 // Float_variable_info;
3441 // Long_variable_info;
3442 // Double_variable_info;
3443 // Null_variable_info;
3444 // UninitializedThis_variable_info;
3445 // Object_variable_info;
3446 // Uninitialized_variable_info;
3447 // }
3448 //
3449 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info(
3450 address& stackmap_p_ref, address stackmap_end, u2 frame_i,
3451 u1 frame_type) {
3452
3453 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag");
3454 u1 tag = *stackmap_p_ref;
3455 stackmap_p_ref++;
3456
3457 switch (tag) {
3458 // Top_variable_info {
3459 // u1 tag = ITEM_Top; /* 0 */
3460 // }
3461 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top
3462 case 0: // fall through
3463
3464 // Integer_variable_info {
3465 // u1 tag = ITEM_Integer; /* 1 */
3466 // }
3467 case ITEM_Integer: // fall through
3468
3469 // Float_variable_info {
3470 // u1 tag = ITEM_Float; /* 2 */
3471 // }
3472 case ITEM_Float: // fall through
3473
3474 // Double_variable_info {
3475 // u1 tag = ITEM_Double; /* 3 */
3476 // }
3477 case ITEM_Double: // fall through
3478
3479 // Long_variable_info {
3480 // u1 tag = ITEM_Long; /* 4 */
3481 // }
3482 case ITEM_Long: // fall through
3483
3484 // Null_variable_info {
3485 // u1 tag = ITEM_Null; /* 5 */
3486 // }
3487 case ITEM_Null: // fall through
3488
3489 // UninitializedThis_variable_info {
3490 // u1 tag = ITEM_UninitializedThis; /* 6 */
3491 // }
3492 case ITEM_UninitializedThis:
3493 // nothing more to do for the above tag types
3494 break;
3495
3496 // Object_variable_info {
3497 // u1 tag = ITEM_Object; /* 7 */
3498 // u2 cpool_index;
3499 // }
3500 case ITEM_Object:
3501 {
3502 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index");
3503 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref);
3504 u2 new_cp_index = find_new_index(cpool_index);
3505 if (new_cp_index != 0) {
3506 log_debug(redefine, class, stackmap)("mapped old cpool_index=%d", cpool_index);
3507 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
3508 cpool_index = new_cp_index;
3509 }
3510 stackmap_p_ref += 2;
3511
3512 log_debug(redefine, class, stackmap)
3513 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i, frame_type, cpool_index);
3514 } break;
3515
3516 // Uninitialized_variable_info {
3517 // u1 tag = ITEM_Uninitialized; /* 8 */
3518 // u2 offset;
3519 // }
3520 case ITEM_Uninitialized:
3521 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset");
3522 stackmap_p_ref += 2;
3523 break;
3524
3525 default:
3526 log_debug(redefine, class, stackmap)("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag);
3527 ShouldNotReachHere();
3528 break;
3529 } // end switch (tag)
3530 } // end rewrite_cp_refs_in_verification_type_info()
3531
3532
3533 // Change the constant pool associated with klass scratch_class to
3534 // scratch_cp. If shrink is true, then scratch_cp_length elements
3535 // are copied from scratch_cp to a smaller constant pool and the
3536 // smaller constant pool is associated with scratch_class.
3537 void VM_RedefineClasses::set_new_constant_pool(
3538 ClassLoaderData* loader_data,
3539 InstanceKlass* scratch_class, constantPoolHandle scratch_cp,
3540 int scratch_cp_length, TRAPS) {
3541 assert(scratch_cp->length() >= scratch_cp_length, "sanity check");
3542
3543 // scratch_cp is a merged constant pool and has enough space for a
3544 // worst case merge situation. We want to associate the minimum
3545 // sized constant pool with the klass to save space.
3546 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK);
3547 constantPoolHandle smaller_cp(THREAD, cp);
3548
3549 // preserve version() value in the smaller copy
3550 int version = scratch_cp->version();
3551 assert(version != 0, "sanity check");
3552 smaller_cp->set_version(version);
3553
3554 // attach klass to new constant pool
3555 // reference to the cp holder is needed for copy_operands()
3556 smaller_cp->set_pool_holder(scratch_class);
3557
3558 smaller_cp->copy_fields(scratch_cp());
3559
3560 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
3561 if (HAS_PENDING_EXCEPTION) {
3562 // Exception is handled in the caller
3563 loader_data->add_to_deallocate_list(smaller_cp());
3564 return;
3565 }
3566 scratch_cp = smaller_cp;
3567
3568 // attach new constant pool to klass
3569 scratch_class->set_constants(scratch_cp());
3570 scratch_cp->initialize_unresolved_klasses(loader_data, CHECK);
3571
3572 int i; // for portability
3573
3574 // update each field in klass to use new constant pool indices as needed
3575 for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) {
3576 jshort cur_index = fs.name_index();
3577 jshort new_index = find_new_index(cur_index);
3578 if (new_index != 0) {
3579 log_trace(redefine, class, constantpool)("field-name_index change: %d to %d", cur_index, new_index);
3580 fs.set_name_index(new_index);
3581 }
3582 cur_index = fs.signature_index();
3583 new_index = find_new_index(cur_index);
3584 if (new_index != 0) {
3585 log_trace(redefine, class, constantpool)("field-signature_index change: %d to %d", cur_index, new_index);
3586 fs.set_signature_index(new_index);
3587 }
3588 cur_index = fs.initval_index();
3589 new_index = find_new_index(cur_index);
3590 if (new_index != 0) {
3591 log_trace(redefine, class, constantpool)("field-initval_index change: %d to %d", cur_index, new_index);
3592 fs.set_initval_index(new_index);
3593 }
3594 cur_index = fs.generic_signature_index();
3595 new_index = find_new_index(cur_index);
3596 if (new_index != 0) {
3597 log_trace(redefine, class, constantpool)("field-generic_signature change: %d to %d", cur_index, new_index);
3598 fs.set_generic_signature_index(new_index);
3599 }
3600 } // end for each field
3601
3602 // Update constant pool indices in the inner classes info to use
3603 // new constant indices as needed. The inner classes info is a
3604 // quadruple:
3605 // (inner_class_info, outer_class_info, inner_name, inner_access_flags)
3606 InnerClassesIterator iter(scratch_class);
3607 for (; !iter.done(); iter.next()) {
3608 int cur_index = iter.inner_class_info_index();
3609 if (cur_index == 0) {
3610 continue; // JVM spec. allows null inner class refs so skip it
3611 }
3612 int new_index = find_new_index(cur_index);
3613 if (new_index != 0) {
3614 log_trace(redefine, class, constantpool)("inner_class_info change: %d to %d", cur_index, new_index);
3615 iter.set_inner_class_info_index(new_index);
3616 }
3617 cur_index = iter.outer_class_info_index();
3618 new_index = find_new_index(cur_index);
3619 if (new_index != 0) {
3620 log_trace(redefine, class, constantpool)("outer_class_info change: %d to %d", cur_index, new_index);
3621 iter.set_outer_class_info_index(new_index);
3622 }
3623 cur_index = iter.inner_name_index();
3624 new_index = find_new_index(cur_index);
3625 if (new_index != 0) {
3626 log_trace(redefine, class, constantpool)("inner_name change: %d to %d", cur_index, new_index);
3627 iter.set_inner_name_index(new_index);
3628 }
3629 } // end for each inner class
3630
3631 // Attach each method in klass to the new constant pool and update
3632 // to use new constant pool indices as needed:
3633 Array<Method*>* methods = scratch_class->methods();
3634 for (i = methods->length() - 1; i >= 0; i--) {
3635 methodHandle method(THREAD, methods->at(i));
3636 method->set_constants(scratch_cp());
3637
3638 int new_index = find_new_index(method->name_index());
3639 if (new_index != 0) {
3640 log_trace(redefine, class, constantpool)
3641 ("method-name_index change: %d to %d", method->name_index(), new_index);
3642 method->set_name_index(new_index);
3643 }
3644 new_index = find_new_index(method->signature_index());
3645 if (new_index != 0) {
3646 log_trace(redefine, class, constantpool)
3647 ("method-signature_index change: %d to %d", method->signature_index(), new_index);
3648 method->set_signature_index(new_index);
3649 }
3650 new_index = find_new_index(method->generic_signature_index());
3651 if (new_index != 0) {
3652 log_trace(redefine, class, constantpool)
3653 ("method-generic_signature_index change: %d to %d", method->generic_signature_index(), new_index);
3654 method->set_generic_signature_index(new_index);
3655 }
3656
3657 // Update constant pool indices in the method's checked exception
3658 // table to use new constant indices as needed.
3659 int cext_length = method->checked_exceptions_length();
3660 if (cext_length > 0) {
3661 CheckedExceptionElement * cext_table =
3662 method->checked_exceptions_start();
3663 for (int j = 0; j < cext_length; j++) {
3664 int cur_index = cext_table[j].class_cp_index;
3665 int new_index = find_new_index(cur_index);
3666 if (new_index != 0) {
3667 log_trace(redefine, class, constantpool)("cext-class_cp_index change: %d to %d", cur_index, new_index);
3668 cext_table[j].class_cp_index = (u2)new_index;
3669 }
3670 } // end for each checked exception table entry
3671 } // end if there are checked exception table entries
3672
3673 // Update each catch type index in the method's exception table
3674 // to use new constant pool indices as needed. The exception table
3675 // holds quadruple entries of the form:
3676 // (beg_bci, end_bci, handler_bci, klass_index)
3677
3678 ExceptionTable ex_table(method());
3679 int ext_length = ex_table.length();
3680
3681 for (int j = 0; j < ext_length; j ++) {
3682 int cur_index = ex_table.catch_type_index(j);
3683 int new_index = find_new_index(cur_index);
3684 if (new_index != 0) {
3685 log_trace(redefine, class, constantpool)("ext-klass_index change: %d to %d", cur_index, new_index);
3686 ex_table.set_catch_type_index(j, new_index);
3687 }
3688 } // end for each exception table entry
3689
3690 // Update constant pool indices in the method's local variable
3691 // table to use new constant indices as needed. The local variable
3692 // table hold sextuple entries of the form:
3693 // (start_pc, length, name_index, descriptor_index, signature_index, slot)
3694 int lvt_length = method->localvariable_table_length();
3695 if (lvt_length > 0) {
3696 LocalVariableTableElement * lv_table =
3697 method->localvariable_table_start();
3698 for (int j = 0; j < lvt_length; j++) {
3699 int cur_index = lv_table[j].name_cp_index;
3700 int new_index = find_new_index(cur_index);
3701 if (new_index != 0) {
3702 log_trace(redefine, class, constantpool)("lvt-name_cp_index change: %d to %d", cur_index, new_index);
3703 lv_table[j].name_cp_index = (u2)new_index;
3704 }
3705 cur_index = lv_table[j].descriptor_cp_index;
3706 new_index = find_new_index(cur_index);
3707 if (new_index != 0) {
3708 log_trace(redefine, class, constantpool)("lvt-descriptor_cp_index change: %d to %d", cur_index, new_index);
3709 lv_table[j].descriptor_cp_index = (u2)new_index;
3710 }
3711 cur_index = lv_table[j].signature_cp_index;
3712 new_index = find_new_index(cur_index);
3713 if (new_index != 0) {
3714 log_trace(redefine, class, constantpool)("lvt-signature_cp_index change: %d to %d", cur_index, new_index);
3715 lv_table[j].signature_cp_index = (u2)new_index;
3716 }
3717 } // end for each local variable table entry
3718 } // end if there are local variable table entries
3719
3720 // Update constant pool indices in the method's method_parameters.
3721 int mp_length = method->method_parameters_length();
3722 if (mp_length > 0) {
3723 MethodParametersElement* elem = method->method_parameters_start();
3724 for (int j = 0; j < mp_length; j++) {
3725 const int cp_index = elem[j].name_cp_index;
3726 const int new_cp_index = find_new_index(cp_index);
3727 if (new_cp_index != 0) {
3728 elem[j].name_cp_index = (u2)new_cp_index;
3729 }
3730 }
3731 }
3732
3733 rewrite_cp_refs_in_stack_map_table(method);
3734 } // end for each method
3735 } // end set_new_constant_pool()
3736
3737
3738 // Unevolving classes may point to methods of the_class directly
3739 // from their constant pool caches, itables, and/or vtables. We
3740 // use the ClassLoaderDataGraph::classes_do() facility and this helper
3741 // to fix up these pointers. MethodData also points to old methods and
3742 // must be cleaned.
3743
3744 // Adjust cpools and vtables closure
3745 void VM_RedefineClasses::AdjustAndCleanMetadata::do_klass(Klass* k) {
3746
3747 // This is a very busy routine. We don't want too much tracing
3748 // printed out.
3749 bool trace_name_printed = false;
3750
3751 // If the class being redefined is java.lang.Object, we need to fix all
3752 // array class vtables also. The _has_redefined_Object flag is global.
3753 // Once the java.lang.Object has been redefined (by the current or one
3754 // of the previous VM_RedefineClasses operations) we have to always
3755 // adjust method entries for array classes.
3756 if (k->is_array_klass() && _has_redefined_Object) {
3757 k->vtable().adjust_method_entries(&trace_name_printed);
3758
3759 } else if (k->is_instance_klass()) {
3760 HandleMark hm(_thread);
3761 InstanceKlass *ik = InstanceKlass::cast(k);
3762
3763 // Clean MethodData of this class's methods so they don't refer to
3764 // old methods that are no longer running.
3765 Array<Method*>* methods = ik->methods();
3766 int num_methods = methods->length();
3767 for (int index = 0; index < num_methods; ++index) {
3768 if (methods->at(index)->method_data() != NULL) {
3769 methods->at(index)->method_data()->clean_weak_method_links();
3770 }
3771 }
3772
3773 // Adjust all vtables, default methods and itables, to clean out old methods.
3774 ResourceMark rm(_thread);
3775 if (ik->vtable_length() > 0) {
3776 ik->vtable().adjust_method_entries(&trace_name_printed);
3777 ik->adjust_default_methods(&trace_name_printed);
3778 }
3779
3780 if (ik->itable_length() > 0) {
3781 ik->itable().adjust_method_entries(&trace_name_printed);
3782 }
3783
3784 // The constant pools in other classes (other_cp) can refer to
3785 // old methods. We have to update method information in
3786 // other_cp's cache. If other_cp has a previous version, then we
3787 // have to repeat the process for each previous version. The
3788 // constant pool cache holds the Method*s for non-virtual
3789 // methods and for virtual, final methods.
3790 //
3791 // Special case: if the current class is being redefined by the current
3792 // VM_RedefineClasses operation, then new_cp has already been attached
3793 // to the_class and old_cp has already been added as a previous version.
3794 // The new_cp doesn't have any cached references to old methods so it
3795 // doesn't need to be updated and we could optimize by skipping it.
3796 // However, the current class can be marked as being redefined by another
3797 // VM_RedefineClasses operation which has already executed its doit_prologue
3798 // and needs cpcache method entries adjusted. For simplicity, the cpcache
3799 // update is done unconditionally. It should result in doing nothing for
3800 // classes being redefined by the current VM_RedefineClasses operation.
3801 // Method entries in the previous version(s) are adjusted as well.
3802 ConstantPoolCache* cp_cache;
3803
3804 // this klass' constant pool cache may need adjustment
3805 ConstantPool* other_cp = ik->constants();
3806 cp_cache = other_cp->cache();
3807 if (cp_cache != NULL) {
3808 cp_cache->adjust_method_entries(&trace_name_printed);
3809 }
3810
3811 // the previous versions' constant pool caches may need adjustment
3812 for (InstanceKlass* pv_node = ik->previous_versions();
3813 pv_node != NULL;
3814 pv_node = pv_node->previous_versions()) {
3815 cp_cache = pv_node->constants()->cache();
3816 if (cp_cache != NULL) {
3817 cp_cache->adjust_method_entries(&trace_name_printed);
3818 }
3819 }
3820 }
3821 }
3822
3823 void VM_RedefineClasses::update_jmethod_ids() {
3824 for (int j = 0; j < _matching_methods_length; ++j) {
3825 Method* old_method = _matching_old_methods[j];
3826 jmethodID jmid = old_method->find_jmethod_id_or_null();
3827 if (jmid != NULL) {
3828 // There is a jmethodID, change it to point to the new method
3829 Method* new_method = _matching_new_methods[j];
3830 Method::change_method_associated_with_jmethod_id(jmid, new_method);
3831 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j],
3832 "should be replaced");
3833 }
3834 }
3835 }
3836
3837 int VM_RedefineClasses::check_methods_and_mark_as_obsolete() {
3838 int emcp_method_count = 0;
3839 int obsolete_count = 0;
3840 int old_index = 0;
3841 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
3842 Method* old_method = _matching_old_methods[j];
3843 Method* new_method = _matching_new_methods[j];
3844 Method* old_array_method;
3845
3846 // Maintain an old_index into the _old_methods array by skipping
3847 // deleted methods
3848 while ((old_array_method = _old_methods->at(old_index)) != old_method) {
3849 ++old_index;
3850 }
3851
3852 if (MethodComparator::methods_EMCP(old_method, new_method)) {
3853 // The EMCP definition from JSR-163 requires the bytecodes to be
3854 // the same with the exception of constant pool indices which may
3855 // differ. However, the constants referred to by those indices
3856 // must be the same.
3857 //
3858 // We use methods_EMCP() for comparison since constant pool
3859 // merging can remove duplicate constant pool entries that were
3860 // present in the old method and removed from the rewritten new
3861 // method. A faster binary comparison function would consider the
3862 // old and new methods to be different when they are actually
3863 // EMCP.
3864 //
3865 // The old and new methods are EMCP and you would think that we
3866 // could get rid of one of them here and now and save some space.
3867 // However, the concept of EMCP only considers the bytecodes and
3868 // the constant pool entries in the comparison. Other things,
3869 // e.g., the line number table (LNT) or the local variable table
3870 // (LVT) don't count in the comparison. So the new (and EMCP)
3871 // method can have a new LNT that we need so we can't just
3872 // overwrite the new method with the old method.
3873 //
3874 // When this routine is called, we have already attached the new
3875 // methods to the_class so the old methods are effectively
3876 // overwritten. However, if an old method is still executing,
3877 // then the old method cannot be collected until sometime after
3878 // the old method call has returned. So the overwriting of old
3879 // methods by new methods will save us space except for those
3880 // (hopefully few) old methods that are still executing.
3881 //
3882 // A method refers to a ConstMethod* and this presents another
3883 // possible avenue to space savings. The ConstMethod* in the
3884 // new method contains possibly new attributes (LNT, LVT, etc).
3885 // At first glance, it seems possible to save space by replacing
3886 // the ConstMethod* in the old method with the ConstMethod*
3887 // from the new method. The old and new methods would share the
3888 // same ConstMethod* and we would save the space occupied by
3889 // the old ConstMethod*. However, the ConstMethod* contains
3890 // a back reference to the containing method. Sharing the
3891 // ConstMethod* between two methods could lead to confusion in
3892 // the code that uses the back reference. This would lead to
3893 // brittle code that could be broken in non-obvious ways now or
3894 // in the future.
3895 //
3896 // Another possibility is to copy the ConstMethod* from the new
3897 // method to the old method and then overwrite the new method with
3898 // the old method. Since the ConstMethod* contains the bytecodes
3899 // for the method embedded in the oop, this option would change
3900 // the bytecodes out from under any threads executing the old
3901 // method and make the thread's bcp invalid. Since EMCP requires
3902 // that the bytecodes be the same modulo constant pool indices, it
3903 // is straight forward to compute the correct new bcp in the new
3904 // ConstMethod* from the old bcp in the old ConstMethod*. The
3905 // time consuming part would be searching all the frames in all
3906 // of the threads to find all of the calls to the old method.
3907 //
3908 // It looks like we will have to live with the limited savings
3909 // that we get from effectively overwriting the old methods
3910 // when the new methods are attached to the_class.
3911
3912 // Count number of methods that are EMCP. The method will be marked
3913 // old but not obsolete if it is EMCP.
3914 emcp_method_count++;
3915
3916 // An EMCP method is _not_ obsolete. An obsolete method has a
3917 // different jmethodID than the current method. An EMCP method
3918 // has the same jmethodID as the current method. Having the
3919 // same jmethodID for all EMCP versions of a method allows for
3920 // a consistent view of the EMCP methods regardless of which
3921 // EMCP method you happen to have in hand. For example, a
3922 // breakpoint set in one EMCP method will work for all EMCP
3923 // versions of the method including the current one.
3924 } else {
3925 // mark obsolete methods as such
3926 old_method->set_is_obsolete();
3927 obsolete_count++;
3928
3929 // obsolete methods need a unique idnum so they become new entries in
3930 // the jmethodID cache in InstanceKlass
3931 assert(old_method->method_idnum() == new_method->method_idnum(), "must match");
3932 u2 num = InstanceKlass::cast(_the_class)->next_method_idnum();
3933 if (num != ConstMethod::UNSET_IDNUM) {
3934 old_method->set_method_idnum(num);
3935 }
3936
3937 // With tracing we try not to "yack" too much. The position of
3938 // this trace assumes there are fewer obsolete methods than
3939 // EMCP methods.
3940 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) {
3941 ResourceMark rm;
3942 log_trace(redefine, class, obsolete, mark)
3943 ("mark %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string());
3944 }
3945 }
3946 old_method->set_is_old();
3947 }
3948 for (int i = 0; i < _deleted_methods_length; ++i) {
3949 Method* old_method = _deleted_methods[i];
3950
3951 assert(!old_method->has_vtable_index(),
3952 "cannot delete methods with vtable entries");;
3953
3954 // Mark all deleted methods as old, obsolete and deleted
3955 old_method->set_is_deleted();
3956 old_method->set_is_old();
3957 old_method->set_is_obsolete();
3958 ++obsolete_count;
3959 // With tracing we try not to "yack" too much. The position of
3960 // this trace assumes there are fewer obsolete methods than
3961 // EMCP methods.
3962 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) {
3963 ResourceMark rm;
3964 log_trace(redefine, class, obsolete, mark)
3965 ("mark deleted %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string());
3966 }
3967 }
3968 assert((emcp_method_count + obsolete_count) == _old_methods->length(),
3969 "sanity check");
3970 log_trace(redefine, class, obsolete, mark)("EMCP_cnt=%d, obsolete_cnt=%d", emcp_method_count, obsolete_count);
3971 return emcp_method_count;
3972 }
3973
3974 // This internal class transfers the native function registration from old methods
3975 // to new methods. It is designed to handle both the simple case of unchanged
3976 // native methods and the complex cases of native method prefixes being added and/or
3977 // removed.
3978 // It expects only to be used during the VM_RedefineClasses op (a safepoint).
3979 //
3980 // This class is used after the new methods have been installed in "the_class".
3981 //
3982 // So, for example, the following must be handled. Where 'm' is a method and
3983 // a number followed by an underscore is a prefix.
3984 //
3985 // Old Name New Name
3986 // Simple transfer to new method m -> m
3987 // Add prefix m -> 1_m
3988 // Remove prefix 1_m -> m
3989 // Simultaneous add of prefixes m -> 3_2_1_m
3990 // Simultaneous removal of prefixes 3_2_1_m -> m
3991 // Simultaneous add and remove 1_m -> 2_m
3992 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m
3993 //
3994 class TransferNativeFunctionRegistration {
3995 private:
3996 InstanceKlass* the_class;
3997 int prefix_count;
3998 char** prefixes;
3999
4000 // Recursively search the binary tree of possibly prefixed method names.
4001 // Iteration could be used if all agents were well behaved. Full tree walk is
4002 // more resilent to agents not cleaning up intermediate methods.
4003 // Branch at each depth in the binary tree is:
4004 // (1) without the prefix.
4005 // (2) with the prefix.
4006 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
4007 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len,
4008 Symbol* signature) {
4009 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len);
4010 if (name_symbol != NULL) {
4011 Method* method = the_class->lookup_method(name_symbol, signature);
4012 if (method != NULL) {
4013 // Even if prefixed, intermediate methods must exist.
4014 if (method->is_native()) {
4015 // Wahoo, we found a (possibly prefixed) version of the method, return it.
4016 return method;
4017 }
4018 if (depth < prefix_count) {
4019 // Try applying further prefixes (other than this one).
4020 method = search_prefix_name_space(depth+1, name_str, name_len, signature);
4021 if (method != NULL) {
4022 return method; // found
4023 }
4024
4025 // Try adding this prefix to the method name and see if it matches
4026 // another method name.
4027 char* prefix = prefixes[depth];
4028 size_t prefix_len = strlen(prefix);
4029 size_t trial_len = name_len + prefix_len;
4030 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
4031 strcpy(trial_name_str, prefix);
4032 strcat(trial_name_str, name_str);
4033 method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
4034 signature);
4035 if (method != NULL) {
4036 // If found along this branch, it was prefixed, mark as such
4037 method->set_is_prefixed_native();
4038 return method; // found
4039 }
4040 }
4041 }
4042 }
4043 return NULL; // This whole branch bore nothing
4044 }
4045
4046 // Return the method name with old prefixes stripped away.
4047 char* method_name_without_prefixes(Method* method) {
4048 Symbol* name = method->name();
4049 char* name_str = name->as_utf8();
4050
4051 // Old prefixing may be defunct, strip prefixes, if any.
4052 for (int i = prefix_count-1; i >= 0; i--) {
4053 char* prefix = prefixes[i];
4054 size_t prefix_len = strlen(prefix);
4055 if (strncmp(prefix, name_str, prefix_len) == 0) {
4056 name_str += prefix_len;
4057 }
4058 }
4059 return name_str;
4060 }
4061
4062 // Strip any prefixes off the old native method, then try to find a
4063 // (possibly prefixed) new native that matches it.
4064 Method* strip_and_search_for_new_native(Method* method) {
4065 ResourceMark rm;
4066 char* name_str = method_name_without_prefixes(method);
4067 return search_prefix_name_space(0, name_str, strlen(name_str),
4068 method->signature());
4069 }
4070
4071 public:
4072
4073 // Construct a native method transfer processor for this class.
4074 TransferNativeFunctionRegistration(InstanceKlass* _the_class) {
4075 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
4076
4077 the_class = _the_class;
4078 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
4079 }
4080
4081 // Attempt to transfer any of the old or deleted methods that are native
4082 void transfer_registrations(Method** old_methods, int methods_length) {
4083 for (int j = 0; j < methods_length; j++) {
4084 Method* old_method = old_methods[j];
4085
4086 if (old_method->is_native() && old_method->has_native_function()) {
4087 Method* new_method = strip_and_search_for_new_native(old_method);
4088 if (new_method != NULL) {
4089 // Actually set the native function in the new method.
4090 // Redefine does not send events (except CFLH), certainly not this
4091 // behind the scenes re-registration.
4092 new_method->set_native_function(old_method->native_function(),
4093 !Method::native_bind_event_is_interesting);
4094 }
4095 }
4096 }
4097 }
4098 };
4099
4100 // Don't lose the association between a native method and its JNI function.
4101 void VM_RedefineClasses::transfer_old_native_function_registrations(InstanceKlass* the_class) {
4102 TransferNativeFunctionRegistration transfer(the_class);
4103 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length);
4104 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length);
4105 }
4106
4107 // Deoptimize all compiled code that depends on the classes redefined.
4108 //
4109 // If the can_redefine_classes capability is obtained in the onload
4110 // phase then the compiler has recorded all dependencies from startup.
4111 // In that case we need only deoptimize and throw away all compiled code
4112 // that depends on the class.
4113 //
4114 // If can_redefine_classes is obtained sometime after the onload
4115 // phase then the dependency information may be incomplete. In that case
4116 // the first call to RedefineClasses causes all compiled code to be
4117 // thrown away. As can_redefine_classes has been obtained then
4118 // all future compilations will record dependencies so second and
4119 // subsequent calls to RedefineClasses need only throw away code
4120 // that depends on the class.
4121 //
4122
4123 void VM_RedefineClasses::flush_dependent_code() {
4124 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
4125
4126 bool deopt_needed;
4127
4128 // This is the first redefinition, mark all the nmethods for deoptimization
4129 if (!JvmtiExport::all_dependencies_are_recorded()) {
4130 log_debug(redefine, class, nmethod)("Marked all nmethods for deopt");
4131 CodeCache::mark_all_nmethods_for_evol_deoptimization();
4132 deopt_needed = true;
4133 } else {
4134 int deopt = CodeCache::mark_dependents_for_evol_deoptimization();
4135 log_debug(redefine, class, nmethod)("Marked %d dependent nmethods for deopt", deopt);
4136 deopt_needed = (deopt != 0);
4137 }
4138
4139 if (deopt_needed) {
4140 CodeCache::flush_evol_dependents();
4141 }
4142
4143 // From now on we know that the dependency information is complete
4144 JvmtiExport::set_all_dependencies_are_recorded(true);
4145 }
4146
4147 void VM_RedefineClasses::compute_added_deleted_matching_methods() {
4148 Method* old_method;
4149 Method* new_method;
4150
4151 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
4152 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
4153 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length());
4154 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
4155
4156 _matching_methods_length = 0;
4157 _deleted_methods_length = 0;
4158 _added_methods_length = 0;
4159
4160 int nj = 0;
4161 int oj = 0;
4162 while (true) {
4163 if (oj >= _old_methods->length()) {
4164 if (nj >= _new_methods->length()) {
4165 break; // we've looked at everything, done
4166 }
4167 // New method at the end
4168 new_method = _new_methods->at(nj);
4169 _added_methods[_added_methods_length++] = new_method;
4170 ++nj;
4171 } else if (nj >= _new_methods->length()) {
4172 // Old method, at the end, is deleted
4173 old_method = _old_methods->at(oj);
4174 _deleted_methods[_deleted_methods_length++] = old_method;
4175 ++oj;
4176 } else {
4177 old_method = _old_methods->at(oj);
4178 new_method = _new_methods->at(nj);
4179 if (old_method->name() == new_method->name()) {
4180 if (old_method->signature() == new_method->signature()) {
4181 _matching_old_methods[_matching_methods_length ] = old_method;
4182 _matching_new_methods[_matching_methods_length++] = new_method;
4183 ++nj;
4184 ++oj;
4185 } else {
4186 // added overloaded have already been moved to the end,
4187 // so this is a deleted overloaded method
4188 _deleted_methods[_deleted_methods_length++] = old_method;
4189 ++oj;
4190 }
4191 } else { // names don't match
4192 if (old_method->name()->fast_compare(new_method->name()) > 0) {
4193 // new method
4194 _added_methods[_added_methods_length++] = new_method;
4195 ++nj;
4196 } else {
4197 // deleted method
4198 _deleted_methods[_deleted_methods_length++] = old_method;
4199 ++oj;
4200 }
4201 }
4202 }
4203 }
4204 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
4205 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
4206 }
4207
4208
4209 void VM_RedefineClasses::swap_annotations(InstanceKlass* the_class,
4210 InstanceKlass* scratch_class) {
4211 // Swap annotation fields values
4212 Annotations* old_annotations = the_class->annotations();
4213 the_class->set_annotations(scratch_class->annotations());
4214 scratch_class->set_annotations(old_annotations);
4215 }
4216
4217
4218 // Install the redefinition of a class:
4219 // - house keeping (flushing breakpoints and caches, deoptimizing
4220 // dependent compiled code)
4221 // - replacing parts in the_class with parts from scratch_class
4222 // - adding a weak reference to track the obsolete but interesting
4223 // parts of the_class
4224 // - adjusting constant pool caches and vtables in other classes
4225 // that refer to methods in the_class. These adjustments use the
4226 // ClassLoaderDataGraph::classes_do() facility which only allows
4227 // a helper method to be specified. The interesting parameters
4228 // that we would like to pass to the helper method are saved in
4229 // static global fields in the VM operation.
4230 void VM_RedefineClasses::redefine_single_class(Thread* current, jclass the_jclass,
4231 InstanceKlass* scratch_class) {
4232
4233 HandleMark hm(current); // make sure handles from this call are freed
4234
4235 if (log_is_enabled(Info, redefine, class, timer)) {
4236 _timer_rsc_phase1.start();
4237 }
4238
4239 InstanceKlass* the_class = get_ik(the_jclass);
4240
4241 // Set a flag to control and optimize adjusting method entries
4242 _has_redefined_Object |= the_class == vmClasses::Object_klass();
4243
4244 // Remove all breakpoints in methods of this class
4245 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
4246 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class);
4247
4248 _old_methods = the_class->methods();
4249 _new_methods = scratch_class->methods();
4250 _the_class = the_class;
4251 compute_added_deleted_matching_methods();
4252 update_jmethod_ids();
4253
4254 _any_class_has_resolved_methods = the_class->has_resolved_methods() || _any_class_has_resolved_methods;
4255
4256 // Attach new constant pool to the original klass. The original
4257 // klass still refers to the old constant pool (for now).
4258 scratch_class->constants()->set_pool_holder(the_class);
4259
4260 #if 0
4261 // In theory, with constant pool merging in place we should be able
4262 // to save space by using the new, merged constant pool in place of
4263 // the old constant pool(s). By "pool(s)" I mean the constant pool in
4264 // the klass version we are replacing now and any constant pool(s) in
4265 // previous versions of klass. Nice theory, doesn't work in practice.
4266 // When this code is enabled, even simple programs throw NullPointer
4267 // exceptions. I'm guessing that this is caused by some constant pool
4268 // cache difference between the new, merged constant pool and the
4269 // constant pool that was just being used by the klass. I'm keeping
4270 // this code around to archive the idea, but the code has to remain
4271 // disabled for now.
4272
4273 // Attach each old method to the new constant pool. This can be
4274 // done here since we are past the bytecode verification and
4275 // constant pool optimization phases.
4276 for (int i = _old_methods->length() - 1; i >= 0; i--) {
4277 Method* method = _old_methods->at(i);
4278 method->set_constants(scratch_class->constants());
4279 }
4280
4281 // NOTE: this doesn't work because you can redefine the same class in two
4282 // threads, each getting their own constant pool data appended to the
4283 // original constant pool. In order for the new methods to work when they
4284 // become old methods, they need to keep their updated copy of the constant pool.
4285
4286 {
4287 // walk all previous versions of the klass
4288 InstanceKlass *ik = the_class;
4289 PreviousVersionWalker pvw(ik);
4290 do {
4291 ik = pvw.next_previous_version();
4292 if (ik != NULL) {
4293
4294 // attach previous version of klass to the new constant pool
4295 ik->set_constants(scratch_class->constants());
4296
4297 // Attach each method in the previous version of klass to the
4298 // new constant pool
4299 Array<Method*>* prev_methods = ik->methods();
4300 for (int i = prev_methods->length() - 1; i >= 0; i--) {
4301 Method* method = prev_methods->at(i);
4302 method->set_constants(scratch_class->constants());
4303 }
4304 }
4305 } while (ik != NULL);
4306 }
4307 #endif
4308
4309 // Replace methods and constantpool
4310 the_class->set_methods(_new_methods);
4311 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods,
4312 // and to be able to undo operation easily.
4313
4314 Array<int>* old_ordering = the_class->method_ordering();
4315 the_class->set_method_ordering(scratch_class->method_ordering());
4316 scratch_class->set_method_ordering(old_ordering);
4317
4318 ConstantPool* old_constants = the_class->constants();
4319 the_class->set_constants(scratch_class->constants());
4320 scratch_class->set_constants(old_constants); // See the previous comment.
4321 #if 0
4322 // We are swapping the guts of "the new class" with the guts of "the
4323 // class". Since the old constant pool has just been attached to "the
4324 // new class", it seems logical to set the pool holder in the old
4325 // constant pool also. However, doing this will change the observable
4326 // class hierarchy for any old methods that are still executing. A
4327 // method can query the identity of its "holder" and this query uses
4328 // the method's constant pool link to find the holder. The change in
4329 // holding class from "the class" to "the new class" can confuse
4330 // things.
4331 //
4332 // Setting the old constant pool's holder will also cause
4333 // verification done during vtable initialization below to fail.
4334 // During vtable initialization, the vtable's class is verified to be
4335 // a subtype of the method's holder. The vtable's class is "the
4336 // class" and the method's holder is gotten from the constant pool
4337 // link in the method itself. For "the class"'s directly implemented
4338 // methods, the method holder is "the class" itself (as gotten from
4339 // the new constant pool). The check works fine in this case. The
4340 // check also works fine for methods inherited from super classes.
4341 //
4342 // Miranda methods are a little more complicated. A miranda method is
4343 // provided by an interface when the class implementing the interface
4344 // does not provide its own method. These interfaces are implemented
4345 // internally as an InstanceKlass. These special instanceKlasses
4346 // share the constant pool of the class that "implements" the
4347 // interface. By sharing the constant pool, the method holder of a
4348 // miranda method is the class that "implements" the interface. In a
4349 // non-redefine situation, the subtype check works fine. However, if
4350 // the old constant pool's pool holder is modified, then the check
4351 // fails because there is no class hierarchy relationship between the
4352 // vtable's class and "the new class".
4353
4354 old_constants->set_pool_holder(scratch_class());
4355 #endif
4356
4357 // track number of methods that are EMCP for add_previous_version() call below
4358 int emcp_method_count = check_methods_and_mark_as_obsolete();
4359 transfer_old_native_function_registrations(the_class);
4360
4361 // The class file bytes from before any retransformable agents mucked
4362 // with them was cached on the scratch class, move to the_class.
4363 // Note: we still want to do this if nothing needed caching since it
4364 // should get cleared in the_class too.
4365 if (the_class->get_cached_class_file() == 0) {
4366 // the_class doesn't have a cache yet so copy it
4367 the_class->set_cached_class_file(scratch_class->get_cached_class_file());
4368 }
4369 else if (scratch_class->get_cached_class_file() !=
4370 the_class->get_cached_class_file()) {
4371 // The same class can be present twice in the scratch classes list or there
4372 // are multiple concurrent RetransformClasses calls on different threads.
4373 // In such cases we have to deallocate scratch_class cached_class_file.
4374 os::free(scratch_class->get_cached_class_file());
4375 }
4376
4377 // NULL out in scratch class to not delete twice. The class to be redefined
4378 // always owns these bytes.
4379 scratch_class->set_cached_class_file(NULL);
4380
4381 // Replace inner_classes
4382 Array<u2>* old_inner_classes = the_class->inner_classes();
4383 the_class->set_inner_classes(scratch_class->inner_classes());
4384 scratch_class->set_inner_classes(old_inner_classes);
4385
4386 // Initialize the vtable and interface table after
4387 // methods have been rewritten
4388 // no exception should happen here since we explicitly
4389 // do not check loader constraints.
4390 // compare_and_normalize_class_versions has already checked:
4391 // - classloaders unchanged, signatures unchanged
4392 // - all instanceKlasses for redefined classes reused & contents updated
4393 the_class->vtable().initialize_vtable();
4394 the_class->itable().initialize_itable();
4395
4396 // Leave arrays of jmethodIDs and itable index cache unchanged
4397
4398 // Copy the "source file name" attribute from new class version
4399 the_class->set_source_file_name_index(
4400 scratch_class->source_file_name_index());
4401
4402 // Copy the "source debug extension" attribute from new class version
4403 the_class->set_source_debug_extension(
4404 scratch_class->source_debug_extension(),
4405 scratch_class->source_debug_extension() == NULL ? 0 :
4406 (int)strlen(scratch_class->source_debug_extension()));
4407
4408 // Use of javac -g could be different in the old and the new
4409 if (scratch_class->access_flags().has_localvariable_table() !=
4410 the_class->access_flags().has_localvariable_table()) {
4411
4412 AccessFlags flags = the_class->access_flags();
4413 if (scratch_class->access_flags().has_localvariable_table()) {
4414 flags.set_has_localvariable_table();
4415 } else {
4416 flags.clear_has_localvariable_table();
4417 }
4418 the_class->set_access_flags(flags);
4419 }
4420
4421 swap_annotations(the_class, scratch_class);
4422
4423 // Replace minor version number of class file
4424 u2 old_minor_version = the_class->constants()->minor_version();
4425 the_class->constants()->set_minor_version(scratch_class->constants()->minor_version());
4426 scratch_class->constants()->set_minor_version(old_minor_version);
4427
4428 // Replace major version number of class file
4429 u2 old_major_version = the_class->constants()->major_version();
4430 the_class->constants()->set_major_version(scratch_class->constants()->major_version());
4431 scratch_class->constants()->set_major_version(old_major_version);
4432
4433 // Replace CP indexes for class and name+type of enclosing method
4434 u2 old_class_idx = the_class->enclosing_method_class_index();
4435 u2 old_method_idx = the_class->enclosing_method_method_index();
4436 the_class->set_enclosing_method_indices(
4437 scratch_class->enclosing_method_class_index(),
4438 scratch_class->enclosing_method_method_index());
4439 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx);
4440
4441 the_class->set_has_been_redefined();
4442
4443 // Scratch class is unloaded but still needs cleaning, and skipping for CDS.
4444 scratch_class->set_is_scratch_class();
4445
4446 // keep track of previous versions of this class
4447 the_class->add_previous_version(scratch_class, emcp_method_count);
4448
4449 _timer_rsc_phase1.stop();
4450 if (log_is_enabled(Info, redefine, class, timer)) {
4451 _timer_rsc_phase2.start();
4452 }
4453
4454 if (the_class->oop_map_cache() != NULL) {
4455 // Flush references to any obsolete methods from the oop map cache
4456 // so that obsolete methods are not pinned.
4457 the_class->oop_map_cache()->flush_obsolete_entries();
4458 }
4459
4460 increment_class_counter(the_class);
4461
4462 if (EventClassRedefinition::is_enabled()) {
4463 EventClassRedefinition event;
4464 event.set_classModificationCount(java_lang_Class::classRedefinedCount(the_class->java_mirror()));
4465 event.set_redefinedClass(the_class);
4466 event.set_redefinitionId(_id);
4467 event.commit();
4468 }
4469
4470 {
4471 ResourceMark rm(current);
4472 // increment the classRedefinedCount field in the_class and in any
4473 // direct and indirect subclasses of the_class
4474 log_info(redefine, class, load)
4475 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)",
4476 the_class->external_name(), java_lang_Class::classRedefinedCount(the_class->java_mirror()), os::available_memory() >> 10);
4477 Events::log_redefinition(current, "redefined class name=%s, count=%d",
4478 the_class->external_name(),
4479 java_lang_Class::classRedefinedCount(the_class->java_mirror()));
4480
4481 }
4482 _timer_rsc_phase2.stop();
4483
4484 } // end redefine_single_class()
4485
4486
4487 // Increment the classRedefinedCount field in the specific InstanceKlass
4488 // and in all direct and indirect subclasses.
4489 void VM_RedefineClasses::increment_class_counter(InstanceKlass* ik) {
4490 for (ClassHierarchyIterator iter(ik); !iter.done(); iter.next()) {
4491 // Only update instanceKlasses
4492 Klass* sub = iter.klass();
4493 if (sub->is_instance_klass()) {
4494 oop class_mirror = InstanceKlass::cast(sub)->java_mirror();
4495 Klass* class_oop = java_lang_Class::as_Klass(class_mirror);
4496 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
4497 java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
4498
4499 if (class_oop != _the_class) {
4500 // _the_class count is printed at end of redefine_single_class()
4501 log_debug(redefine, class, subclass)("updated count in subclass=%s to %d", ik->external_name(), new_count);
4502 }
4503 }
4504 }
4505 }
4506
4507 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) {
4508 bool no_old_methods = true; // be optimistic
4509
4510 // Both array and instance classes have vtables.
4511 // a vtable should never contain old or obsolete methods
4512 ResourceMark rm(_thread);
4513 if (k->vtable_length() > 0 &&
4514 !k->vtable().check_no_old_or_obsolete_entries()) {
4515 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4516 log_trace(redefine, class, obsolete, metadata)
4517 ("klassVtable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4518 k->signature_name());
4519 k->vtable().dump_vtable();
4520 }
4521 no_old_methods = false;
4522 }
4523
4524 if (k->is_instance_klass()) {
4525 HandleMark hm(_thread);
4526 InstanceKlass *ik = InstanceKlass::cast(k);
4527
4528 // an itable should never contain old or obsolete methods
4529 if (ik->itable_length() > 0 &&
4530 !ik->itable().check_no_old_or_obsolete_entries()) {
4531 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4532 log_trace(redefine, class, obsolete, metadata)
4533 ("klassItable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4534 ik->signature_name());
4535 ik->itable().dump_itable();
4536 }
4537 no_old_methods = false;
4538 }
4539
4540 // the constant pool cache should never contain non-deleted old or obsolete methods
4541 if (ik->constants() != NULL &&
4542 ik->constants()->cache() != NULL &&
4543 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) {
4544 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4545 log_trace(redefine, class, obsolete, metadata)
4546 ("cp-cache::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4547 ik->signature_name());
4548 ik->constants()->cache()->dump_cache();
4549 }
4550 no_old_methods = false;
4551 }
4552 }
4553
4554 // print and fail guarantee if old methods are found.
4555 if (!no_old_methods) {
4556 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4557 dump_methods();
4558 } else {
4559 log_trace(redefine, class)("Use the '-Xlog:redefine+class*:' option "
4560 "to see more info about the following guarantee() failure.");
4561 }
4562 guarantee(false, "OLD and/or OBSOLETE method(s) found");
4563 }
4564 }
4565
4566 u8 VM_RedefineClasses::next_id() {
4567 while (true) {
4568 u8 id = _id_counter;
4569 u8 next_id = id + 1;
4570 u8 result = Atomic::cmpxchg(&_id_counter, id, next_id);
4571 if (result == id) {
4572 return next_id;
4573 }
4574 }
4575 }
4576
4577 void VM_RedefineClasses::dump_methods() {
4578 int j;
4579 log_trace(redefine, class, dump)("_old_methods --");
4580 for (j = 0; j < _old_methods->length(); ++j) {
4581 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4582 Method* m = _old_methods->at(j);
4583 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4584 m->access_flags().print_on(&log_stream);
4585 log_stream.print(" -- ");
4586 m->print_name(&log_stream);
4587 log_stream.cr();
4588 }
4589 log_trace(redefine, class, dump)("_new_methods --");
4590 for (j = 0; j < _new_methods->length(); ++j) {
4591 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4592 Method* m = _new_methods->at(j);
4593 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4594 m->access_flags().print_on(&log_stream);
4595 log_stream.print(" -- ");
4596 m->print_name(&log_stream);
4597 log_stream.cr();
4598 }
4599 log_trace(redefine, class, dump)("_matching_methods --");
4600 for (j = 0; j < _matching_methods_length; ++j) {
4601 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4602 Method* m = _matching_old_methods[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();
4607 log_stream.cr();
4608
4609 m = _matching_new_methods[j];
4610 log_stream.print(" (%5d) ", m->vtable_index());
4611 m->access_flags().print_on(&log_stream);
4612 log_stream.cr();
4613 }
4614 log_trace(redefine, class, dump)("_deleted_methods --");
4615 for (j = 0; j < _deleted_methods_length; ++j) {
4616 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4617 Method* m = _deleted_methods[j];
4618 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4619 m->access_flags().print_on(&log_stream);
4620 log_stream.print(" -- ");
4621 m->print_name(&log_stream);
4622 log_stream.cr();
4623 }
4624 log_trace(redefine, class, dump)("_added_methods --");
4625 for (j = 0; j < _added_methods_length; ++j) {
4626 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4627 Method* m = _added_methods[j];
4628 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4629 m->access_flags().print_on(&log_stream);
4630 log_stream.print(" -- ");
4631 m->print_name(&log_stream);
4632 log_stream.cr();
4633 }
4634 }
4635
4636 void VM_RedefineClasses::print_on_error(outputStream* st) const {
4637 VM_Operation::print_on_error(st);
4638 if (_the_class != NULL) {
4639 ResourceMark rm;
4640 st->print_cr(", redefining class %s", _the_class->external_name());
4641 }
4642 }