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