1 /*
2 * Copyright (c) 2003, 2011, 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 "classfile/systemDictionary.hpp"
27 #include "classfile/verifier.hpp"
28 #include "code/codeCache.hpp"
29 #include "interpreter/oopMapCache.hpp"
30 #include "interpreter/rewriter.hpp"
31 #include "memory/gcLocker.hpp"
32 #include "memory/universe.inline.hpp"
33 #include "oops/klassVtable.hpp"
34 #include "prims/jvmtiImpl.hpp"
35 #include "prims/jvmtiRedefineClasses.hpp"
36 #include "prims/methodComparator.hpp"
37 #include "runtime/deoptimization.hpp"
38 #include "runtime/relocator.hpp"
39 #include "utilities/bitMap.inline.hpp"
40
41
42 objArrayOop VM_RedefineClasses::_old_methods = NULL;
43 objArrayOop VM_RedefineClasses::_new_methods = NULL;
44 methodOop* VM_RedefineClasses::_matching_old_methods = NULL;
45 methodOop* VM_RedefineClasses::_matching_new_methods = NULL;
46 methodOop* VM_RedefineClasses::_deleted_methods = NULL;
47 methodOop* VM_RedefineClasses::_added_methods = NULL;
48 int VM_RedefineClasses::_matching_methods_length = 0;
49 int VM_RedefineClasses::_deleted_methods_length = 0;
50 int VM_RedefineClasses::_added_methods_length = 0;
51 klassOop VM_RedefineClasses::_the_class_oop = NULL;
52
53
54 VM_RedefineClasses::VM_RedefineClasses(jint class_count,
55 const jvmtiClassDefinition *class_defs,
56 JvmtiClassLoadKind class_load_kind) {
57 _class_count = class_count;
58 _class_defs = class_defs;
59 _class_load_kind = class_load_kind;
60 _res = JVMTI_ERROR_NONE;
61 }
62
63 bool VM_RedefineClasses::doit_prologue() {
64 if (_class_count == 0) {
65 _res = JVMTI_ERROR_NONE;
66 return false;
67 }
68 if (_class_defs == NULL) {
69 _res = JVMTI_ERROR_NULL_POINTER;
70 return false;
71 }
72 for (int i = 0; i < _class_count; i++) {
73 if (_class_defs[i].klass == NULL) {
74 _res = JVMTI_ERROR_INVALID_CLASS;
75 return false;
76 }
77 if (_class_defs[i].class_byte_count == 0) {
78 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT;
79 return false;
80 }
81 if (_class_defs[i].class_bytes == NULL) {
82 _res = JVMTI_ERROR_NULL_POINTER;
83 return false;
84 }
85 }
86
87 // Start timer after all the sanity checks; not quite accurate, but
88 // better than adding a bunch of stop() calls.
89 RC_TIMER_START(_timer_vm_op_prologue);
90
91 // We first load new class versions in the prologue, because somewhere down the
92 // call chain it is required that the current thread is a Java thread.
93 _res = load_new_class_versions(Thread::current());
94 if (_res != JVMTI_ERROR_NONE) {
95 // Free os::malloc allocated memory in load_new_class_version.
96 os::free(_scratch_classes);
97 RC_TIMER_STOP(_timer_vm_op_prologue);
98 return false;
99 }
100
101 RC_TIMER_STOP(_timer_vm_op_prologue);
102 return true;
103 }
104
105 void VM_RedefineClasses::doit() {
106 Thread *thread = Thread::current();
107
108 if (UseSharedSpaces) {
109 // Sharing is enabled so we remap the shared readonly space to
110 // shared readwrite, private just in case we need to redefine
111 // a shared class. We do the remap during the doit() phase of
112 // the safepoint to be safer.
113 if (!CompactingPermGenGen::remap_shared_readonly_as_readwrite()) {
114 RC_TRACE_WITH_THREAD(0x00000001, thread,
115 ("failed to remap shared readonly space to readwrite, private"));
116 _res = JVMTI_ERROR_INTERNAL;
117 return;
118 }
119 }
120
121 for (int i = 0; i < _class_count; i++) {
122 redefine_single_class(_class_defs[i].klass, _scratch_classes[i], thread);
123 }
124 // Disable any dependent concurrent compilations
125 SystemDictionary::notice_modification();
126
127 // Set flag indicating that some invariants are no longer true.
128 // See jvmtiExport.hpp for detailed explanation.
129 JvmtiExport::set_has_redefined_a_class();
130
131 #ifdef ASSERT
132 SystemDictionary::classes_do(check_class, thread);
133 #endif
134 }
135
136 void VM_RedefineClasses::doit_epilogue() {
137 // Free os::malloc allocated memory.
138 // The memory allocated in redefine will be free'ed in next VM operation.
139 os::free(_scratch_classes);
140
141 if (RC_TRACE_ENABLED(0x00000004)) {
142 // Used to have separate timers for "doit" and "all", but the timer
143 // overhead skewed the measurements.
144 jlong doit_time = _timer_rsc_phase1.milliseconds() +
145 _timer_rsc_phase2.milliseconds();
146 jlong all_time = _timer_vm_op_prologue.milliseconds() + doit_time;
147
148 RC_TRACE(0x00000004, ("vm_op: all=" UINT64_FORMAT
149 " prologue=" UINT64_FORMAT " doit=" UINT64_FORMAT, all_time,
150 _timer_vm_op_prologue.milliseconds(), doit_time));
151 RC_TRACE(0x00000004,
152 ("redefine_single_class: phase1=" UINT64_FORMAT " phase2=" UINT64_FORMAT,
153 _timer_rsc_phase1.milliseconds(), _timer_rsc_phase2.milliseconds()));
154 }
155 }
156
157 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) {
158 // classes for primitives cannot be redefined
159 if (java_lang_Class::is_primitive(klass_mirror)) {
160 return false;
161 }
162 klassOop the_class_oop = java_lang_Class::as_klassOop(klass_mirror);
163 // classes for arrays cannot be redefined
164 if (the_class_oop == NULL || !Klass::cast(the_class_oop)->oop_is_instance()) {
165 return false;
166 }
167 return true;
168 }
169
170 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p
171 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For
172 // direct CP entries, there is just the current entry to append. For
173 // indirect and double-indirect CP entries, there are zero or more
174 // referenced CP entries along with the current entry to append.
175 // Indirect and double-indirect CP entries are handled by recursive
176 // calls to append_entry() as needed. The referenced CP entries are
177 // always appended to *merge_cp_p before the referee CP entry. These
178 // referenced CP entries may already exist in *merge_cp_p in which case
179 // there is nothing extra to append and only the current entry is
180 // appended.
181 void VM_RedefineClasses::append_entry(constantPoolHandle scratch_cp,
182 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p,
183 TRAPS) {
184
185 // append is different depending on entry tag type
186 switch (scratch_cp->tag_at(scratch_i).value()) {
187
188 // The old verifier is implemented outside the VM. It loads classes,
189 // but does not resolve constant pool entries directly so we never
190 // see Class entries here with the old verifier. Similarly the old
191 // verifier does not like Class entries in the input constant pool.
192 // The split-verifier is implemented in the VM so it can optionally
193 // and directly resolve constant pool entries to load classes. The
194 // split-verifier can accept either Class entries or UnresolvedClass
195 // entries in the input constant pool. We revert the appended copy
196 // back to UnresolvedClass so that either verifier will be happy
197 // with the constant pool entry.
198 case JVM_CONSTANT_Class:
199 {
200 // revert the copy to JVM_CONSTANT_UnresolvedClass
201 (*merge_cp_p)->unresolved_klass_at_put(*merge_cp_length_p,
202 scratch_cp->klass_name_at(scratch_i));
203
204 if (scratch_i != *merge_cp_length_p) {
205 // The new entry in *merge_cp_p is at a different index than
206 // the new entry in scratch_cp so we need to map the index values.
207 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
208 }
209 (*merge_cp_length_p)++;
210 } break;
211
212 // these are direct CP entries so they can be directly appended,
213 // but double and long take two constant pool entries
214 case JVM_CONSTANT_Double: // fall through
215 case JVM_CONSTANT_Long:
216 {
217 constantPoolOopDesc::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
218 THREAD);
219
220 if (scratch_i != *merge_cp_length_p) {
221 // The new entry in *merge_cp_p is at a different index than
222 // the new entry in scratch_cp so we need to map the index values.
223 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
224 }
225 (*merge_cp_length_p) += 2;
226 } break;
227
228 // these are direct CP entries so they can be directly appended
229 case JVM_CONSTANT_Float: // fall through
230 case JVM_CONSTANT_Integer: // fall through
231 case JVM_CONSTANT_Utf8: // fall through
232
233 // This was an indirect CP entry, but it has been changed into
234 // an interned string so this entry can be directly appended.
235 case JVM_CONSTANT_String: // fall through
236
237 // These were indirect CP entries, but they have been changed into
238 // Symbol*s so these entries can be directly appended.
239 case JVM_CONSTANT_UnresolvedClass: // fall through
240 case JVM_CONSTANT_UnresolvedString:
241 {
242 constantPoolOopDesc::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
243 THREAD);
244
245 if (scratch_i != *merge_cp_length_p) {
246 // The new entry in *merge_cp_p is at a different index than
247 // the new entry in scratch_cp so we need to map the index values.
248 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
249 }
250 (*merge_cp_length_p)++;
251 } break;
252
253 // this is an indirect CP entry so it needs special handling
254 case JVM_CONSTANT_NameAndType:
255 {
256 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i);
257 int new_name_ref_i = 0;
258 bool match = (name_ref_i < *merge_cp_length_p) &&
259 scratch_cp->compare_entry_to(name_ref_i, *merge_cp_p, name_ref_i,
260 THREAD);
261 if (!match) {
262 // forward reference in *merge_cp_p or not a direct match
263
264 int found_i = scratch_cp->find_matching_entry(name_ref_i, *merge_cp_p,
265 THREAD);
266 if (found_i != 0) {
267 guarantee(found_i != name_ref_i,
268 "compare_entry_to() and find_matching_entry() do not agree");
269
270 // Found a matching entry somewhere else in *merge_cp_p so
271 // just need a mapping entry.
272 new_name_ref_i = found_i;
273 map_index(scratch_cp, name_ref_i, found_i);
274 } else {
275 // no match found so we have to append this entry to *merge_cp_p
276 append_entry(scratch_cp, name_ref_i, merge_cp_p, merge_cp_length_p,
277 THREAD);
278 // The above call to append_entry() can only append one entry
279 // so the post call query of *merge_cp_length_p is only for
280 // the sake of consistency.
281 new_name_ref_i = *merge_cp_length_p - 1;
282 }
283 }
284
285 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i);
286 int new_signature_ref_i = 0;
287 match = (signature_ref_i < *merge_cp_length_p) &&
288 scratch_cp->compare_entry_to(signature_ref_i, *merge_cp_p,
289 signature_ref_i, THREAD);
290 if (!match) {
291 // forward reference in *merge_cp_p or not a direct match
292
293 int found_i = scratch_cp->find_matching_entry(signature_ref_i,
294 *merge_cp_p, THREAD);
295 if (found_i != 0) {
296 guarantee(found_i != signature_ref_i,
297 "compare_entry_to() and find_matching_entry() do not agree");
298
299 // Found a matching entry somewhere else in *merge_cp_p so
300 // just need a mapping entry.
301 new_signature_ref_i = found_i;
302 map_index(scratch_cp, signature_ref_i, found_i);
303 } else {
304 // no match found so we have to append this entry to *merge_cp_p
305 append_entry(scratch_cp, signature_ref_i, merge_cp_p,
306 merge_cp_length_p, THREAD);
307 // The above call to append_entry() can only append one entry
308 // so the post call query of *merge_cp_length_p is only for
309 // the sake of consistency.
310 new_signature_ref_i = *merge_cp_length_p - 1;
311 }
312 }
313
314 // If the referenced entries already exist in *merge_cp_p, then
315 // both new_name_ref_i and new_signature_ref_i will both be 0.
316 // In that case, all we are appending is the current entry.
317 if (new_name_ref_i == 0) {
318 new_name_ref_i = name_ref_i;
319 } else {
320 RC_TRACE(0x00080000,
321 ("NameAndType entry@%d name_ref_index change: %d to %d",
322 *merge_cp_length_p, name_ref_i, new_name_ref_i));
323 }
324 if (new_signature_ref_i == 0) {
325 new_signature_ref_i = signature_ref_i;
326 } else {
327 RC_TRACE(0x00080000,
328 ("NameAndType entry@%d signature_ref_index change: %d to %d",
329 *merge_cp_length_p, signature_ref_i, new_signature_ref_i));
330 }
331
332 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p,
333 new_name_ref_i, new_signature_ref_i);
334 if (scratch_i != *merge_cp_length_p) {
335 // The new entry in *merge_cp_p is at a different index than
336 // the new entry in scratch_cp so we need to map the index values.
337 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
338 }
339 (*merge_cp_length_p)++;
340 } break;
341
342 // this is a double-indirect CP entry so it needs special handling
343 case JVM_CONSTANT_Fieldref: // fall through
344 case JVM_CONSTANT_InterfaceMethodref: // fall through
345 case JVM_CONSTANT_Methodref:
346 {
347 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i);
348 int new_klass_ref_i = 0;
349 bool match = (klass_ref_i < *merge_cp_length_p) &&
350 scratch_cp->compare_entry_to(klass_ref_i, *merge_cp_p, klass_ref_i,
351 THREAD);
352 if (!match) {
353 // forward reference in *merge_cp_p or not a direct match
354
355 int found_i = scratch_cp->find_matching_entry(klass_ref_i, *merge_cp_p,
356 THREAD);
357 if (found_i != 0) {
358 guarantee(found_i != klass_ref_i,
359 "compare_entry_to() and find_matching_entry() do not agree");
360
361 // Found a matching entry somewhere else in *merge_cp_p so
362 // just need a mapping entry.
363 new_klass_ref_i = found_i;
364 map_index(scratch_cp, klass_ref_i, found_i);
365 } else {
366 // no match found so we have to append this entry to *merge_cp_p
367 append_entry(scratch_cp, klass_ref_i, merge_cp_p, merge_cp_length_p,
368 THREAD);
369 // The above call to append_entry() can only append one entry
370 // so the post call query of *merge_cp_length_p is only for
371 // the sake of consistency. Without the optimization where we
372 // use JVM_CONSTANT_UnresolvedClass, then up to two entries
373 // could be appended.
374 new_klass_ref_i = *merge_cp_length_p - 1;
375 }
376 }
377
378 int name_and_type_ref_i =
379 scratch_cp->uncached_name_and_type_ref_index_at(scratch_i);
380 int new_name_and_type_ref_i = 0;
381 match = (name_and_type_ref_i < *merge_cp_length_p) &&
382 scratch_cp->compare_entry_to(name_and_type_ref_i, *merge_cp_p,
383 name_and_type_ref_i, THREAD);
384 if (!match) {
385 // forward reference in *merge_cp_p or not a direct match
386
387 int found_i = scratch_cp->find_matching_entry(name_and_type_ref_i,
388 *merge_cp_p, THREAD);
389 if (found_i != 0) {
390 guarantee(found_i != name_and_type_ref_i,
391 "compare_entry_to() and find_matching_entry() do not agree");
392
393 // Found a matching entry somewhere else in *merge_cp_p so
394 // just need a mapping entry.
395 new_name_and_type_ref_i = found_i;
396 map_index(scratch_cp, name_and_type_ref_i, found_i);
397 } else {
398 // no match found so we have to append this entry to *merge_cp_p
399 append_entry(scratch_cp, name_and_type_ref_i, merge_cp_p,
400 merge_cp_length_p, THREAD);
401 // The above call to append_entry() can append more than
402 // one entry so the post call query of *merge_cp_length_p
403 // is required in order to get the right index for the
404 // JVM_CONSTANT_NameAndType entry.
405 new_name_and_type_ref_i = *merge_cp_length_p - 1;
406 }
407 }
408
409 // If the referenced entries already exist in *merge_cp_p, then
410 // both new_klass_ref_i and new_name_and_type_ref_i will both be
411 // 0. In that case, all we are appending is the current entry.
412 if (new_klass_ref_i == 0) {
413 new_klass_ref_i = klass_ref_i;
414 }
415 if (new_name_and_type_ref_i == 0) {
416 new_name_and_type_ref_i = name_and_type_ref_i;
417 }
418
419 const char *entry_name;
420 switch (scratch_cp->tag_at(scratch_i).value()) {
421 case JVM_CONSTANT_Fieldref:
422 entry_name = "Fieldref";
423 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i,
424 new_name_and_type_ref_i);
425 break;
426 case JVM_CONSTANT_InterfaceMethodref:
427 entry_name = "IFMethodref";
428 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p,
429 new_klass_ref_i, new_name_and_type_ref_i);
430 break;
431 case JVM_CONSTANT_Methodref:
432 entry_name = "Methodref";
433 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i,
434 new_name_and_type_ref_i);
435 break;
436 default:
437 guarantee(false, "bad switch");
438 break;
439 }
440
441 if (klass_ref_i != new_klass_ref_i) {
442 RC_TRACE(0x00080000, ("%s entry@%d class_index changed: %d to %d",
443 entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i));
444 }
445 if (name_and_type_ref_i != new_name_and_type_ref_i) {
446 RC_TRACE(0x00080000,
447 ("%s entry@%d name_and_type_index changed: %d to %d",
448 entry_name, *merge_cp_length_p, name_and_type_ref_i,
449 new_name_and_type_ref_i));
450 }
451
452 if (scratch_i != *merge_cp_length_p) {
453 // The new entry in *merge_cp_p is at a different index than
454 // the new entry in scratch_cp so we need to map the index values.
455 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
456 }
457 (*merge_cp_length_p)++;
458 } break;
459
460 // At this stage, Class or UnresolvedClass could be here, but not
461 // ClassIndex
462 case JVM_CONSTANT_ClassIndex: // fall through
463
464 // Invalid is used as the tag for the second constant pool entry
465 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
466 // not be seen by itself.
467 case JVM_CONSTANT_Invalid: // fall through
468
469 // At this stage, String or UnresolvedString could be here, but not
470 // StringIndex
471 case JVM_CONSTANT_StringIndex: // fall through
472
473 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be
474 // here
475 case JVM_CONSTANT_UnresolvedClassInError: // fall through
476
477 default:
478 {
479 // leave a breadcrumb
480 jbyte bad_value = scratch_cp->tag_at(scratch_i).value();
481 ShouldNotReachHere();
482 } break;
483 } // end switch tag value
484 } // end append_entry()
485
486
487 void VM_RedefineClasses::swap_all_method_annotations(int i, int j, instanceKlassHandle scratch_class) {
488 typeArrayOop save;
489
490 save = scratch_class->get_method_annotations_of(i);
491 scratch_class->set_method_annotations_of(i, scratch_class->get_method_annotations_of(j));
492 scratch_class->set_method_annotations_of(j, save);
493
494 save = scratch_class->get_method_parameter_annotations_of(i);
495 scratch_class->set_method_parameter_annotations_of(i, scratch_class->get_method_parameter_annotations_of(j));
496 scratch_class->set_method_parameter_annotations_of(j, save);
497
498 save = scratch_class->get_method_default_annotations_of(i);
499 scratch_class->set_method_default_annotations_of(i, scratch_class->get_method_default_annotations_of(j));
500 scratch_class->set_method_default_annotations_of(j, save);
501 }
502
503
504 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions(
505 instanceKlassHandle the_class,
506 instanceKlassHandle scratch_class) {
507 int i;
508
509 // Check superclasses, or rather their names, since superclasses themselves can be
510 // requested to replace.
511 // Check for NULL superclass first since this might be java.lang.Object
512 if (the_class->super() != scratch_class->super() &&
513 (the_class->super() == NULL || scratch_class->super() == NULL ||
514 Klass::cast(the_class->super())->name() !=
515 Klass::cast(scratch_class->super())->name())) {
516 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
517 }
518
519 // Check if the number, names and order of directly implemented interfaces are the same.
520 // I think in principle we should just check if the sets of names of directly implemented
521 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the
522 // .java file, also changes in .class file) should not matter. However, comparing sets is
523 // technically a bit more difficult, and, more importantly, I am not sure at present that the
524 // order of interfaces does not matter on the implementation level, i.e. that the VM does not
525 // rely on it somewhere.
526 objArrayOop k_interfaces = the_class->local_interfaces();
527 objArrayOop k_new_interfaces = scratch_class->local_interfaces();
528 int n_intfs = k_interfaces->length();
529 if (n_intfs != k_new_interfaces->length()) {
530 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
531 }
532 for (i = 0; i < n_intfs; i++) {
533 if (Klass::cast((klassOop) k_interfaces->obj_at(i))->name() !=
534 Klass::cast((klassOop) k_new_interfaces->obj_at(i))->name()) {
535 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
536 }
537 }
538
539 // Check whether class is in the error init state.
540 if (the_class->is_in_error_state()) {
541 // TBD #5057930: special error code is needed in 1.6
542 return JVMTI_ERROR_INVALID_CLASS;
543 }
544
545 // Check whether class modifiers are the same.
546 jushort old_flags = (jushort) the_class->access_flags().get_flags();
547 jushort new_flags = (jushort) scratch_class->access_flags().get_flags();
548 if (old_flags != new_flags) {
549 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED;
550 }
551
552 // Check if the number, names, types and order of fields declared in these classes
553 // are the same.
554 typeArrayOop k_old_fields = the_class->fields();
555 typeArrayOop k_new_fields = scratch_class->fields();
556 int n_fields = k_old_fields->length();
557 if (n_fields != k_new_fields->length()) {
558 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
559 }
560
561 for (i = 0; i < n_fields; i += instanceKlass::next_offset) {
562 // access
563 old_flags = k_old_fields->ushort_at(i + instanceKlass::access_flags_offset);
564 new_flags = k_new_fields->ushort_at(i + instanceKlass::access_flags_offset);
565 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) {
566 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
567 }
568 // offset
569 if (k_old_fields->short_at(i + instanceKlass::low_offset) !=
570 k_new_fields->short_at(i + instanceKlass::low_offset) ||
571 k_old_fields->short_at(i + instanceKlass::high_offset) !=
572 k_new_fields->short_at(i + instanceKlass::high_offset)) {
573 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
574 }
575 // name and signature
576 jshort name_index = k_old_fields->short_at(i + instanceKlass::name_index_offset);
577 jshort sig_index = k_old_fields->short_at(i +instanceKlass::signature_index_offset);
578 Symbol* name_sym1 = the_class->constants()->symbol_at(name_index);
579 Symbol* sig_sym1 = the_class->constants()->symbol_at(sig_index);
580 name_index = k_new_fields->short_at(i + instanceKlass::name_index_offset);
581 sig_index = k_new_fields->short_at(i + instanceKlass::signature_index_offset);
582 Symbol* name_sym2 = scratch_class->constants()->symbol_at(name_index);
583 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(sig_index);
584 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) {
585 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
586 }
587 }
588
589 // Do a parallel walk through the old and new methods. Detect
590 // cases where they match (exist in both), have been added in
591 // the new methods, or have been deleted (exist only in the
592 // old methods). The class file parser places methods in order
593 // by method name, but does not order overloaded methods by
594 // signature. In order to determine what fate befell the methods,
595 // this code places the overloaded new methods that have matching
596 // old methods in the same order as the old methods and places
597 // new overloaded methods at the end of overloaded methods of
598 // that name. The code for this order normalization is adapted
599 // from the algorithm used in instanceKlass::find_method().
600 // Since we are swapping out of order entries as we find them,
601 // we only have to search forward through the overloaded methods.
602 // Methods which are added and have the same name as an existing
603 // method (but different signature) will be put at the end of
604 // the methods with that name, and the name mismatch code will
605 // handle them.
606 objArrayHandle k_old_methods(the_class->methods());
607 objArrayHandle k_new_methods(scratch_class->methods());
608 int n_old_methods = k_old_methods->length();
609 int n_new_methods = k_new_methods->length();
610
611 int ni = 0;
612 int oi = 0;
613 while (true) {
614 methodOop k_old_method;
615 methodOop k_new_method;
616 enum { matched, added, deleted, undetermined } method_was = undetermined;
617
618 if (oi >= n_old_methods) {
619 if (ni >= n_new_methods) {
620 break; // we've looked at everything, done
621 }
622 // New method at the end
623 k_new_method = (methodOop) k_new_methods->obj_at(ni);
624 method_was = added;
625 } else if (ni >= n_new_methods) {
626 // Old method, at the end, is deleted
627 k_old_method = (methodOop) k_old_methods->obj_at(oi);
628 method_was = deleted;
629 } else {
630 // There are more methods in both the old and new lists
631 k_old_method = (methodOop) k_old_methods->obj_at(oi);
632 k_new_method = (methodOop) k_new_methods->obj_at(ni);
633 if (k_old_method->name() != k_new_method->name()) {
634 // Methods are sorted by method name, so a mismatch means added
635 // or deleted
636 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) {
637 method_was = added;
638 } else {
639 method_was = deleted;
640 }
641 } else if (k_old_method->signature() == k_new_method->signature()) {
642 // Both the name and signature match
643 method_was = matched;
644 } else {
645 // The name matches, but the signature doesn't, which means we have to
646 // search forward through the new overloaded methods.
647 int nj; // outside the loop for post-loop check
648 for (nj = ni + 1; nj < n_new_methods; nj++) {
649 methodOop m = (methodOop)k_new_methods->obj_at(nj);
650 if (k_old_method->name() != m->name()) {
651 // reached another method name so no more overloaded methods
652 method_was = deleted;
653 break;
654 }
655 if (k_old_method->signature() == m->signature()) {
656 // found a match so swap the methods
657 k_new_methods->obj_at_put(ni, m);
658 k_new_methods->obj_at_put(nj, k_new_method);
659 k_new_method = m;
660 method_was = matched;
661 break;
662 }
663 }
664
665 if (nj >= n_new_methods) {
666 // reached the end without a match; so method was deleted
667 method_was = deleted;
668 }
669 }
670 }
671
672 switch (method_was) {
673 case matched:
674 // methods match, be sure modifiers do too
675 old_flags = (jushort) k_old_method->access_flags().get_flags();
676 new_flags = (jushort) k_new_method->access_flags().get_flags();
677 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) {
678 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED;
679 }
680 {
681 u2 new_num = k_new_method->method_idnum();
682 u2 old_num = k_old_method->method_idnum();
683 if (new_num != old_num) {
684 methodOop idnum_owner = scratch_class->method_with_idnum(old_num);
685 if (idnum_owner != NULL) {
686 // There is already a method assigned this idnum -- switch them
687 idnum_owner->set_method_idnum(new_num);
688 }
689 k_new_method->set_method_idnum(old_num);
690 swap_all_method_annotations(old_num, new_num, scratch_class);
691 }
692 }
693 RC_TRACE(0x00008000, ("Method matched: new: %s [%d] == old: %s [%d]",
694 k_new_method->name_and_sig_as_C_string(), ni,
695 k_old_method->name_and_sig_as_C_string(), oi));
696 // advance to next pair of methods
697 ++oi;
698 ++ni;
699 break;
700 case added:
701 // method added, see if it is OK
702 new_flags = (jushort) k_new_method->access_flags().get_flags();
703 if ((new_flags & JVM_ACC_PRIVATE) == 0
704 // hack: private should be treated as final, but alas
705 || (new_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
706 ) {
707 // new methods must be private
708 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
709 }
710 {
711 u2 num = the_class->next_method_idnum();
712 if (num == constMethodOopDesc::UNSET_IDNUM) {
713 // cannot add any more methods
714 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
715 }
716 u2 new_num = k_new_method->method_idnum();
717 methodOop idnum_owner = scratch_class->method_with_idnum(num);
718 if (idnum_owner != NULL) {
719 // There is already a method assigned this idnum -- switch them
720 idnum_owner->set_method_idnum(new_num);
721 }
722 k_new_method->set_method_idnum(num);
723 swap_all_method_annotations(new_num, num, scratch_class);
724 }
725 RC_TRACE(0x00008000, ("Method added: new: %s [%d]",
726 k_new_method->name_and_sig_as_C_string(), ni));
727 ++ni; // advance to next new method
728 break;
729 case deleted:
730 // method deleted, see if it is OK
731 old_flags = (jushort) k_old_method->access_flags().get_flags();
732 if ((old_flags & JVM_ACC_PRIVATE) == 0
733 // hack: private should be treated as final, but alas
734 || (old_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
735 ) {
736 // deleted methods must be private
737 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED;
738 }
739 RC_TRACE(0x00008000, ("Method deleted: old: %s [%d]",
740 k_old_method->name_and_sig_as_C_string(), oi));
741 ++oi; // advance to next old method
742 break;
743 default:
744 ShouldNotReachHere();
745 }
746 }
747
748 return JVMTI_ERROR_NONE;
749 }
750
751
752 // Find new constant pool index value for old constant pool index value
753 // by seaching the index map. Returns zero (0) if there is no mapped
754 // value for the old constant pool index.
755 int VM_RedefineClasses::find_new_index(int old_index) {
756 if (_index_map_count == 0) {
757 // map is empty so nothing can be found
758 return 0;
759 }
760
761 if (old_index < 1 || old_index >= _index_map_p->length()) {
762 // The old_index is out of range so it is not mapped. This should
763 // not happen in regular constant pool merging use, but it can
764 // happen if a corrupt annotation is processed.
765 return 0;
766 }
767
768 int value = _index_map_p->at(old_index);
769 if (value == -1) {
770 // the old_index is not mapped
771 return 0;
772 }
773
774 return value;
775 } // end find_new_index()
776
777
778 // Returns true if the current mismatch is due to a resolved/unresolved
779 // class pair. Otherwise, returns false.
780 bool VM_RedefineClasses::is_unresolved_class_mismatch(constantPoolHandle cp1,
781 int index1, constantPoolHandle cp2, int index2) {
782
783 jbyte t1 = cp1->tag_at(index1).value();
784 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) {
785 return false; // wrong entry type; not our special case
786 }
787
788 jbyte t2 = cp2->tag_at(index2).value();
789 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) {
790 return false; // wrong entry type; not our special case
791 }
792
793 if (t1 == t2) {
794 return false; // not a mismatch; not our special case
795 }
796
797 char *s1 = cp1->klass_name_at(index1)->as_C_string();
798 char *s2 = cp2->klass_name_at(index2)->as_C_string();
799 if (strcmp(s1, s2) != 0) {
800 return false; // strings don't match; not our special case
801 }
802
803 return true; // made it through the gauntlet; this is our special case
804 } // end is_unresolved_class_mismatch()
805
806
807 // Returns true if the current mismatch is due to a resolved/unresolved
808 // string pair. Otherwise, returns false.
809 bool VM_RedefineClasses::is_unresolved_string_mismatch(constantPoolHandle cp1,
810 int index1, constantPoolHandle cp2, int index2) {
811
812 jbyte t1 = cp1->tag_at(index1).value();
813 if (t1 != JVM_CONSTANT_String && t1 != JVM_CONSTANT_UnresolvedString) {
814 return false; // wrong entry type; not our special case
815 }
816
817 jbyte t2 = cp2->tag_at(index2).value();
818 if (t2 != JVM_CONSTANT_String && t2 != JVM_CONSTANT_UnresolvedString) {
819 return false; // wrong entry type; not our special case
820 }
821
822 if (t1 == t2) {
823 return false; // not a mismatch; not our special case
824 }
825
826 char *s1 = cp1->string_at_noresolve(index1);
827 char *s2 = cp2->string_at_noresolve(index2);
828 if (strcmp(s1, s2) != 0) {
829 return false; // strings don't match; not our special case
830 }
831
832 return true; // made it through the gauntlet; this is our special case
833 } // end is_unresolved_string_mismatch()
834
835
836 jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) {
837 // For consistency allocate memory using os::malloc wrapper.
838 _scratch_classes = (instanceKlassHandle *)
839 os::malloc(sizeof(instanceKlassHandle) * _class_count);
840 if (_scratch_classes == NULL) {
841 return JVMTI_ERROR_OUT_OF_MEMORY;
842 }
843
844 ResourceMark rm(THREAD);
845
846 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
847 // state can only be NULL if the current thread is exiting which
848 // should not happen since we're trying to do a RedefineClasses
849 guarantee(state != NULL, "exiting thread calling load_new_class_versions");
850 for (int i = 0; i < _class_count; i++) {
851 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass);
852 // classes for primitives cannot be redefined
853 if (!is_modifiable_class(mirror)) {
854 return JVMTI_ERROR_UNMODIFIABLE_CLASS;
855 }
856 klassOop the_class_oop = java_lang_Class::as_klassOop(mirror);
857 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
858 Symbol* the_class_sym = the_class->name();
859
860 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
861 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
862 ("loading name=%s (avail_mem=" UINT64_FORMAT "K)",
863 the_class->external_name(), os::available_memory() >> 10));
864
865 ClassFileStream st((u1*) _class_defs[i].class_bytes,
866 _class_defs[i].class_byte_count, (char *)"__VM_RedefineClasses__");
867
868 // Parse the stream.
869 Handle the_class_loader(THREAD, the_class->class_loader());
870 Handle protection_domain(THREAD, the_class->protection_domain());
871 // Set redefined class handle in JvmtiThreadState class.
872 // This redefined class is sent to agent event handler for class file
873 // load hook event.
874 state->set_class_being_redefined(&the_class, _class_load_kind);
875
876 klassOop k = SystemDictionary::parse_stream(the_class_sym,
877 the_class_loader,
878 protection_domain,
879 &st,
880 THREAD);
881 // Clear class_being_redefined just to be sure.
882 state->clear_class_being_redefined();
883
884 // TODO: if this is retransform, and nothing changed we can skip it
885
886 instanceKlassHandle scratch_class (THREAD, k);
887
888 if (HAS_PENDING_EXCEPTION) {
889 Symbol* ex_name = PENDING_EXCEPTION->klass()->klass_part()->name();
890 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
891 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("parse_stream exception: '%s'",
892 ex_name->as_C_string()));
893 CLEAR_PENDING_EXCEPTION;
894
895 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) {
896 return JVMTI_ERROR_UNSUPPORTED_VERSION;
897 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) {
898 return JVMTI_ERROR_INVALID_CLASS_FORMAT;
899 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) {
900 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION;
901 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
902 // The message will be "XXX (wrong name: YYY)"
903 return JVMTI_ERROR_NAMES_DONT_MATCH;
904 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
905 return JVMTI_ERROR_OUT_OF_MEMORY;
906 } else { // Just in case more exceptions can be thrown..
907 return JVMTI_ERROR_FAILS_VERIFICATION;
908 }
909 }
910
911 // Ensure class is linked before redefine
912 if (!the_class->is_linked()) {
913 the_class->link_class(THREAD);
914 if (HAS_PENDING_EXCEPTION) {
915 Symbol* ex_name = PENDING_EXCEPTION->klass()->klass_part()->name();
916 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
917 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("link_class exception: '%s'",
918 ex_name->as_C_string()));
919 CLEAR_PENDING_EXCEPTION;
920 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
921 return JVMTI_ERROR_OUT_OF_MEMORY;
922 } else {
923 return JVMTI_ERROR_INTERNAL;
924 }
925 }
926 }
927
928 // Do the validity checks in compare_and_normalize_class_versions()
929 // before verifying the byte codes. By doing these checks first, we
930 // limit the number of functions that require redirection from
931 // the_class to scratch_class. In particular, we don't have to
932 // modify JNI GetSuperclass() and thus won't change its performance.
933 jvmtiError res = compare_and_normalize_class_versions(the_class,
934 scratch_class);
935 if (res != JVMTI_ERROR_NONE) {
936 return res;
937 }
938
939 // verify what the caller passed us
940 {
941 // The bug 6214132 caused the verification to fail.
942 // Information about the_class and scratch_class is temporarily
943 // recorded into jvmtiThreadState. This data is used to redirect
944 // the_class to scratch_class in the JVM_* functions called by the
945 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed
946 // description.
947 RedefineVerifyMark rvm(&the_class, &scratch_class, state);
948 Verifier::verify(
949 scratch_class, Verifier::ThrowException, true, THREAD);
950 }
951
952 if (HAS_PENDING_EXCEPTION) {
953 Symbol* ex_name = PENDING_EXCEPTION->klass()->klass_part()->name();
954 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
955 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
956 ("verify_byte_codes exception: '%s'", ex_name->as_C_string()));
957 CLEAR_PENDING_EXCEPTION;
958 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
959 return JVMTI_ERROR_OUT_OF_MEMORY;
960 } else {
961 // tell the caller the bytecodes are bad
962 return JVMTI_ERROR_FAILS_VERIFICATION;
963 }
964 }
965
966 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD);
967 if (res != JVMTI_ERROR_NONE) {
968 return res;
969 }
970
971 if (VerifyMergedCPBytecodes) {
972 // verify what we have done during constant pool merging
973 {
974 RedefineVerifyMark rvm(&the_class, &scratch_class, state);
975 Verifier::verify(scratch_class, Verifier::ThrowException, true, THREAD);
976 }
977
978 if (HAS_PENDING_EXCEPTION) {
979 Symbol* ex_name = PENDING_EXCEPTION->klass()->klass_part()->name();
980 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
981 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
982 ("verify_byte_codes post merge-CP exception: '%s'",
983 ex_name->as_C_string()));
984 CLEAR_PENDING_EXCEPTION;
985 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
986 return JVMTI_ERROR_OUT_OF_MEMORY;
987 } else {
988 // tell the caller that constant pool merging screwed up
989 return JVMTI_ERROR_INTERNAL;
990 }
991 }
992 }
993
994 Rewriter::rewrite(scratch_class, THREAD);
995 if (HAS_PENDING_EXCEPTION) {
996 Symbol* ex_name = PENDING_EXCEPTION->klass()->klass_part()->name();
997 CLEAR_PENDING_EXCEPTION;
998 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
999 return JVMTI_ERROR_OUT_OF_MEMORY;
1000 } else {
1001 return JVMTI_ERROR_INTERNAL;
1002 }
1003 }
1004
1005 _scratch_classes[i] = scratch_class;
1006
1007 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1008 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
1009 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)",
1010 the_class->external_name(), os::available_memory() >> 10));
1011 }
1012
1013 return JVMTI_ERROR_NONE;
1014 }
1015
1016
1017 // Map old_index to new_index as needed. scratch_cp is only needed
1018 // for RC_TRACE() calls.
1019 void VM_RedefineClasses::map_index(constantPoolHandle scratch_cp,
1020 int old_index, int new_index) {
1021 if (find_new_index(old_index) != 0) {
1022 // old_index is already mapped
1023 return;
1024 }
1025
1026 if (old_index == new_index) {
1027 // no mapping is needed
1028 return;
1029 }
1030
1031 _index_map_p->at_put(old_index, new_index);
1032 _index_map_count++;
1033
1034 RC_TRACE(0x00040000, ("mapped tag %d at index %d to %d",
1035 scratch_cp->tag_at(old_index).value(), old_index, new_index));
1036 } // end map_index()
1037
1038
1039 // Merge old_cp and scratch_cp and return the results of the merge via
1040 // merge_cp_p. The number of entries in *merge_cp_p is returned via
1041 // merge_cp_length_p. The entries in old_cp occupy the same locations
1042 // in *merge_cp_p. Also creates a map of indices from entries in
1043 // scratch_cp to the corresponding entry in *merge_cp_p. Index map
1044 // entries are only created for entries in scratch_cp that occupy a
1045 // different location in *merged_cp_p.
1046 bool VM_RedefineClasses::merge_constant_pools(constantPoolHandle old_cp,
1047 constantPoolHandle scratch_cp, constantPoolHandle *merge_cp_p,
1048 int *merge_cp_length_p, TRAPS) {
1049
1050 if (merge_cp_p == NULL) {
1051 assert(false, "caller must provide scatch constantPool");
1052 return false; // robustness
1053 }
1054 if (merge_cp_length_p == NULL) {
1055 assert(false, "caller must provide scatch CP length");
1056 return false; // robustness
1057 }
1058 // Worst case we need old_cp->length() + scratch_cp()->length(),
1059 // but the caller might be smart so make sure we have at least
1060 // the minimum.
1061 if ((*merge_cp_p)->length() < old_cp->length()) {
1062 assert(false, "merge area too small");
1063 return false; // robustness
1064 }
1065
1066 RC_TRACE_WITH_THREAD(0x00010000, THREAD,
1067 ("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(),
1068 scratch_cp->length()));
1069
1070 {
1071 // Pass 0:
1072 // The old_cp is copied to *merge_cp_p; this means that any code
1073 // using old_cp does not have to change. This work looks like a
1074 // perfect fit for constantPoolOop::copy_cp_to(), but we need to
1075 // handle one special case:
1076 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass
1077 // This will make verification happy.
1078
1079 int old_i; // index into old_cp
1080
1081 // index zero (0) is not used in constantPools
1082 for (old_i = 1; old_i < old_cp->length(); old_i++) {
1083 // leave debugging crumb
1084 jbyte old_tag = old_cp->tag_at(old_i).value();
1085 switch (old_tag) {
1086 case JVM_CONSTANT_Class:
1087 case JVM_CONSTANT_UnresolvedClass:
1088 // revert the copy to JVM_CONSTANT_UnresolvedClass
1089 // May be resolving while calling this so do the same for
1090 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition)
1091 (*merge_cp_p)->unresolved_klass_at_put(old_i,
1092 old_cp->klass_name_at(old_i));
1093 break;
1094
1095 case JVM_CONSTANT_Double:
1096 case JVM_CONSTANT_Long:
1097 // just copy the entry to *merge_cp_p, but double and long take
1098 // two constant pool entries
1099 constantPoolOopDesc::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1100 old_i++;
1101 break;
1102
1103 default:
1104 // just copy the entry to *merge_cp_p
1105 constantPoolOopDesc::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1106 break;
1107 }
1108 } // end for each old_cp entry
1109
1110 // We don't need to sanity check that *merge_cp_length_p is within
1111 // *merge_cp_p bounds since we have the minimum on-entry check above.
1112 (*merge_cp_length_p) = old_i;
1113 }
1114
1115 // merge_cp_len should be the same as old_cp->length() at this point
1116 // so this trace message is really a "warm-and-breathing" message.
1117 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1118 ("after pass 0: merge_cp_len=%d", *merge_cp_length_p));
1119
1120 int scratch_i; // index into scratch_cp
1121 {
1122 // Pass 1a:
1123 // Compare scratch_cp entries to the old_cp entries that we have
1124 // already copied to *merge_cp_p. In this pass, we are eliminating
1125 // exact duplicates (matching entry at same index) so we only
1126 // compare entries in the common indice range.
1127 int increment = 1;
1128 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length());
1129 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) {
1130 switch (scratch_cp->tag_at(scratch_i).value()) {
1131 case JVM_CONSTANT_Double:
1132 case JVM_CONSTANT_Long:
1133 // double and long take two constant pool entries
1134 increment = 2;
1135 break;
1136
1137 default:
1138 increment = 1;
1139 break;
1140 }
1141
1142 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p,
1143 scratch_i, CHECK_0);
1144 if (match) {
1145 // found a match at the same index so nothing more to do
1146 continue;
1147 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i,
1148 *merge_cp_p, scratch_i)) {
1149 // The mismatch in compare_entry_to() above is because of a
1150 // resolved versus unresolved class entry at the same index
1151 // with the same string value. Since Pass 0 reverted any
1152 // class entries to unresolved class entries in *merge_cp_p,
1153 // we go with the unresolved class entry.
1154 continue;
1155 } else if (is_unresolved_string_mismatch(scratch_cp, scratch_i,
1156 *merge_cp_p, scratch_i)) {
1157 // The mismatch in compare_entry_to() above is because of a
1158 // resolved versus unresolved string entry at the same index
1159 // with the same string value. We can live with whichever
1160 // happens to be at scratch_i in *merge_cp_p.
1161 continue;
1162 }
1163
1164 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p,
1165 CHECK_0);
1166 if (found_i != 0) {
1167 guarantee(found_i != scratch_i,
1168 "compare_entry_to() and find_matching_entry() do not agree");
1169
1170 // Found a matching entry somewhere else in *merge_cp_p so
1171 // just need a mapping entry.
1172 map_index(scratch_cp, scratch_i, found_i);
1173 continue;
1174 }
1175
1176 // The find_matching_entry() call above could fail to find a match
1177 // due to a resolved versus unresolved class or string entry situation
1178 // like we solved above with the is_unresolved_*_mismatch() calls.
1179 // However, we would have to call is_unresolved_*_mismatch() over
1180 // all of *merge_cp_p (potentially) and that doesn't seem to be
1181 // worth the time.
1182
1183 // No match found so we have to append this entry and any unique
1184 // referenced entries to *merge_cp_p.
1185 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1186 CHECK_0);
1187 }
1188 }
1189
1190 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1191 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1192 *merge_cp_length_p, scratch_i, _index_map_count));
1193
1194 if (scratch_i < scratch_cp->length()) {
1195 // Pass 1b:
1196 // old_cp is smaller than scratch_cp so there are entries in
1197 // scratch_cp that we have not yet processed. We take care of
1198 // those now.
1199 int increment = 1;
1200 for (; scratch_i < scratch_cp->length(); scratch_i += increment) {
1201 switch (scratch_cp->tag_at(scratch_i).value()) {
1202 case JVM_CONSTANT_Double:
1203 case JVM_CONSTANT_Long:
1204 // double and long take two constant pool entries
1205 increment = 2;
1206 break;
1207
1208 default:
1209 increment = 1;
1210 break;
1211 }
1212
1213 int found_i =
1214 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0);
1215 if (found_i != 0) {
1216 // Found a matching entry somewhere else in *merge_cp_p so
1217 // just need a mapping entry.
1218 map_index(scratch_cp, scratch_i, found_i);
1219 continue;
1220 }
1221
1222 // No match found so we have to append this entry and any unique
1223 // referenced entries to *merge_cp_p.
1224 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1225 CHECK_0);
1226 }
1227
1228 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1229 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1230 *merge_cp_length_p, scratch_i, _index_map_count));
1231 }
1232
1233 return true;
1234 } // end merge_constant_pools()
1235
1236
1237 // Merge constant pools between the_class and scratch_class and
1238 // potentially rewrite bytecodes in scratch_class to use the merged
1239 // constant pool.
1240 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite(
1241 instanceKlassHandle the_class, instanceKlassHandle scratch_class,
1242 TRAPS) {
1243 // worst case merged constant pool length is old and new combined
1244 int merge_cp_length = the_class->constants()->length()
1245 + scratch_class->constants()->length();
1246
1247 constantPoolHandle old_cp(THREAD, the_class->constants());
1248 constantPoolHandle scratch_cp(THREAD, scratch_class->constants());
1249
1250 // Constant pools are not easily reused so we allocate a new one
1251 // each time.
1252 // merge_cp is created unsafe for concurrent GC processing. It
1253 // should be marked safe before discarding it. Even though
1254 // garbage, if it crosses a card boundary, it may be scanned
1255 // in order to find the start of the first complete object on the card.
1256 constantPoolHandle merge_cp(THREAD,
1257 oopFactory::new_constantPool(merge_cp_length,
1258 oopDesc::IsUnsafeConc,
1259 THREAD));
1260 int orig_length = old_cp->orig_length();
1261 if (orig_length == 0) {
1262 // This old_cp is an actual original constant pool. We save
1263 // the original length in the merged constant pool so that
1264 // merge_constant_pools() can be more efficient. If a constant
1265 // pool has a non-zero orig_length() value, then that constant
1266 // pool was created by a merge operation in RedefineClasses.
1267 merge_cp->set_orig_length(old_cp->length());
1268 } else {
1269 // This old_cp is a merged constant pool from a previous
1270 // RedefineClasses() calls so just copy the orig_length()
1271 // value.
1272 merge_cp->set_orig_length(old_cp->orig_length());
1273 }
1274
1275 ResourceMark rm(THREAD);
1276 _index_map_count = 0;
1277 _index_map_p = new intArray(scratch_cp->length(), -1);
1278
1279 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp,
1280 &merge_cp_length, THREAD);
1281 if (!result) {
1282 // The merge can fail due to memory allocation failure or due
1283 // to robustness checks.
1284 return JVMTI_ERROR_INTERNAL;
1285 }
1286
1287 RC_TRACE_WITH_THREAD(0x00010000, THREAD,
1288 ("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count));
1289
1290 if (_index_map_count == 0) {
1291 // there is nothing to map between the new and merged constant pools
1292
1293 if (old_cp->length() == scratch_cp->length()) {
1294 // The old and new constant pools are the same length and the
1295 // index map is empty. This means that the three constant pools
1296 // are equivalent (but not the same). Unfortunately, the new
1297 // constant pool has not gone through link resolution nor have
1298 // the new class bytecodes gone through constant pool cache
1299 // rewriting so we can't use the old constant pool with the new
1300 // class.
1301
1302 merge_cp()->set_is_conc_safe(true);
1303 merge_cp = constantPoolHandle(); // toss the merged constant pool
1304 } else if (old_cp->length() < scratch_cp->length()) {
1305 // The old constant pool has fewer entries than the new constant
1306 // pool and the index map is empty. This means the new constant
1307 // pool is a superset of the old constant pool. However, the old
1308 // class bytecodes have already gone through constant pool cache
1309 // rewriting so we can't use the new constant pool with the old
1310 // class.
1311
1312 merge_cp()->set_is_conc_safe(true);
1313 merge_cp = constantPoolHandle(); // toss the merged constant pool
1314 } else {
1315 // The old constant pool has more entries than the new constant
1316 // pool and the index map is empty. This means that both the old
1317 // and merged constant pools are supersets of the new constant
1318 // pool.
1319
1320 // Replace the new constant pool with a shrunken copy of the
1321 // merged constant pool; the previous new constant pool will
1322 // get GCed.
1323 set_new_constant_pool(scratch_class, merge_cp, merge_cp_length, true,
1324 THREAD);
1325 // drop local ref to the merged constant pool
1326 merge_cp()->set_is_conc_safe(true);
1327 merge_cp = constantPoolHandle();
1328 }
1329 } else {
1330 if (RC_TRACE_ENABLED(0x00040000)) {
1331 // don't want to loop unless we are tracing
1332 int count = 0;
1333 for (int i = 1; i < _index_map_p->length(); i++) {
1334 int value = _index_map_p->at(i);
1335
1336 if (value != -1) {
1337 RC_TRACE_WITH_THREAD(0x00040000, THREAD,
1338 ("index_map[%d]: old=%d new=%d", count, i, value));
1339 count++;
1340 }
1341 }
1342 }
1343
1344 // We have entries mapped between the new and merged constant pools
1345 // so we have to rewrite some constant pool references.
1346 if (!rewrite_cp_refs(scratch_class, THREAD)) {
1347 return JVMTI_ERROR_INTERNAL;
1348 }
1349
1350 // Replace the new constant pool with a shrunken copy of the
1351 // merged constant pool so now the rewritten bytecodes have
1352 // valid references; the previous new constant pool will get
1353 // GCed.
1354 set_new_constant_pool(scratch_class, merge_cp, merge_cp_length, true,
1355 THREAD);
1356 merge_cp()->set_is_conc_safe(true);
1357 }
1358 assert(old_cp()->is_conc_safe(), "Just checking");
1359 assert(scratch_cp()->is_conc_safe(), "Just checking");
1360
1361 return JVMTI_ERROR_NONE;
1362 } // end merge_cp_and_rewrite()
1363
1364
1365 // Rewrite constant pool references in klass scratch_class.
1366 bool VM_RedefineClasses::rewrite_cp_refs(instanceKlassHandle scratch_class,
1367 TRAPS) {
1368
1369 // rewrite constant pool references in the methods:
1370 if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) {
1371 // propagate failure back to caller
1372 return false;
1373 }
1374
1375 // rewrite constant pool references in the class_annotations:
1376 if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) {
1377 // propagate failure back to caller
1378 return false;
1379 }
1380
1381 // rewrite constant pool references in the fields_annotations:
1382 if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) {
1383 // propagate failure back to caller
1384 return false;
1385 }
1386
1387 // rewrite constant pool references in the methods_annotations:
1388 if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) {
1389 // propagate failure back to caller
1390 return false;
1391 }
1392
1393 // rewrite constant pool references in the methods_parameter_annotations:
1394 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class,
1395 THREAD)) {
1396 // propagate failure back to caller
1397 return false;
1398 }
1399
1400 // rewrite constant pool references in the methods_default_annotations:
1401 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class,
1402 THREAD)) {
1403 // propagate failure back to caller
1404 return false;
1405 }
1406
1407 return true;
1408 } // end rewrite_cp_refs()
1409
1410
1411 // Rewrite constant pool references in the methods.
1412 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(
1413 instanceKlassHandle scratch_class, TRAPS) {
1414
1415 objArrayHandle methods(THREAD, scratch_class->methods());
1416
1417 if (methods.is_null() || methods->length() == 0) {
1418 // no methods so nothing to do
1419 return true;
1420 }
1421
1422 // rewrite constant pool references in the methods:
1423 for (int i = methods->length() - 1; i >= 0; i--) {
1424 methodHandle method(THREAD, (methodOop)methods->obj_at(i));
1425 methodHandle new_method;
1426 rewrite_cp_refs_in_method(method, &new_method, CHECK_false);
1427 if (!new_method.is_null()) {
1428 // the method has been replaced so save the new method version
1429 methods->obj_at_put(i, new_method());
1430 }
1431 }
1432
1433 return true;
1434 }
1435
1436
1437 // Rewrite constant pool references in the specific method. This code
1438 // was adapted from Rewriter::rewrite_method().
1439 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method,
1440 methodHandle *new_method_p, TRAPS) {
1441
1442 *new_method_p = methodHandle(); // default is no new method
1443
1444 // We cache a pointer to the bytecodes here in code_base. If GC
1445 // moves the methodOop, then the bytecodes will also move which
1446 // will likely cause a crash. We create a No_Safepoint_Verifier
1447 // object to detect whether we pass a possible safepoint in this
1448 // code block.
1449 No_Safepoint_Verifier nsv;
1450
1451 // Bytecodes and their length
1452 address code_base = method->code_base();
1453 int code_length = method->code_size();
1454
1455 int bc_length;
1456 for (int bci = 0; bci < code_length; bci += bc_length) {
1457 address bcp = code_base + bci;
1458 Bytecodes::Code c = (Bytecodes::Code)(*bcp);
1459
1460 bc_length = Bytecodes::length_for(c);
1461 if (bc_length == 0) {
1462 // More complicated bytecodes report a length of zero so
1463 // we have to try again a slightly different way.
1464 bc_length = Bytecodes::length_at(method(), bcp);
1465 }
1466
1467 assert(bc_length != 0, "impossible bytecode length");
1468
1469 switch (c) {
1470 case Bytecodes::_ldc:
1471 {
1472 int cp_index = *(bcp + 1);
1473 int new_index = find_new_index(cp_index);
1474
1475 if (StressLdcRewrite && new_index == 0) {
1476 // If we are stressing ldc -> ldc_w rewriting, then we
1477 // always need a new_index value.
1478 new_index = cp_index;
1479 }
1480 if (new_index != 0) {
1481 // the original index is mapped so we have more work to do
1482 if (!StressLdcRewrite && new_index <= max_jubyte) {
1483 // The new value can still use ldc instead of ldc_w
1484 // unless we are trying to stress ldc -> ldc_w rewriting
1485 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1486 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
1487 bcp, cp_index, new_index));
1488 *(bcp + 1) = new_index;
1489 } else {
1490 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1491 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d",
1492 Bytecodes::name(c), bcp, cp_index, new_index));
1493 // the new value needs ldc_w instead of ldc
1494 u_char inst_buffer[4]; // max instruction size is 4 bytes
1495 bcp = (address)inst_buffer;
1496 // construct new instruction sequence
1497 *bcp = Bytecodes::_ldc_w;
1498 bcp++;
1499 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w.
1500 // See comment below for difference between put_Java_u2()
1501 // and put_native_u2().
1502 Bytes::put_Java_u2(bcp, new_index);
1503
1504 Relocator rc(method, NULL /* no RelocatorListener needed */);
1505 methodHandle m;
1506 {
1507 Pause_No_Safepoint_Verifier pnsv(&nsv);
1508
1509 // ldc is 2 bytes and ldc_w is 3 bytes
1510 m = rc.insert_space_at(bci, 3, inst_buffer, THREAD);
1511 if (m.is_null() || HAS_PENDING_EXCEPTION) {
1512 guarantee(false, "insert_space_at() failed");
1513 }
1514 }
1515
1516 // return the new method so that the caller can update
1517 // the containing class
1518 *new_method_p = method = m;
1519 // switch our bytecode processing loop from the old method
1520 // to the new method
1521 code_base = method->code_base();
1522 code_length = method->code_size();
1523 bcp = code_base + bci;
1524 c = (Bytecodes::Code)(*bcp);
1525 bc_length = Bytecodes::length_for(c);
1526 assert(bc_length != 0, "sanity check");
1527 } // end we need ldc_w instead of ldc
1528 } // end if there is a mapped index
1529 } break;
1530
1531 // these bytecodes have a two-byte constant pool index
1532 case Bytecodes::_anewarray : // fall through
1533 case Bytecodes::_checkcast : // fall through
1534 case Bytecodes::_getfield : // fall through
1535 case Bytecodes::_getstatic : // fall through
1536 case Bytecodes::_instanceof : // fall through
1537 case Bytecodes::_invokeinterface: // fall through
1538 case Bytecodes::_invokespecial : // fall through
1539 case Bytecodes::_invokestatic : // fall through
1540 case Bytecodes::_invokevirtual : // fall through
1541 case Bytecodes::_ldc_w : // fall through
1542 case Bytecodes::_ldc2_w : // fall through
1543 case Bytecodes::_multianewarray : // fall through
1544 case Bytecodes::_new : // fall through
1545 case Bytecodes::_putfield : // fall through
1546 case Bytecodes::_putstatic :
1547 {
1548 address p = bcp + 1;
1549 int cp_index = Bytes::get_Java_u2(p);
1550 int new_index = find_new_index(cp_index);
1551 if (new_index != 0) {
1552 // the original index is mapped so update w/ new value
1553 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1554 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
1555 bcp, cp_index, new_index));
1556 // Rewriter::rewrite_method() uses put_native_u2() in this
1557 // situation because it is reusing the constant pool index
1558 // location for a native index into the constantPoolCache.
1559 // Since we are updating the constant pool index prior to
1560 // verification and constantPoolCache initialization, we
1561 // need to keep the new index in Java byte order.
1562 Bytes::put_Java_u2(p, new_index);
1563 }
1564 } break;
1565 }
1566 } // end for each bytecode
1567 } // end rewrite_cp_refs_in_method()
1568
1569
1570 // Rewrite constant pool references in the class_annotations field.
1571 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(
1572 instanceKlassHandle scratch_class, TRAPS) {
1573
1574 typeArrayHandle class_annotations(THREAD,
1575 scratch_class->class_annotations());
1576 if (class_annotations.is_null() || class_annotations->length() == 0) {
1577 // no class_annotations so nothing to do
1578 return true;
1579 }
1580
1581 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1582 ("class_annotations length=%d", class_annotations->length()));
1583
1584 int byte_i = 0; // byte index into class_annotations
1585 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i,
1586 THREAD);
1587 }
1588
1589
1590 // Rewrite constant pool references in an annotations typeArray. This
1591 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute
1592 // that is described in section 4.8.15 of the 2nd-edition of the VM spec:
1593 //
1594 // annotations_typeArray {
1595 // u2 num_annotations;
1596 // annotation annotations[num_annotations];
1597 // }
1598 //
1599 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray(
1600 typeArrayHandle annotations_typeArray, int &byte_i_ref, TRAPS) {
1601
1602 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1603 // not enough room for num_annotations field
1604 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1605 ("length() is too small for num_annotations field"));
1606 return false;
1607 }
1608
1609 u2 num_annotations = Bytes::get_Java_u2((address)
1610 annotations_typeArray->byte_at_addr(byte_i_ref));
1611 byte_i_ref += 2;
1612
1613 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1614 ("num_annotations=%d", num_annotations));
1615
1616 int calc_num_annotations = 0;
1617 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
1618 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
1619 byte_i_ref, THREAD)) {
1620 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1621 ("bad annotation_struct at %d", calc_num_annotations));
1622 // propagate failure back to caller
1623 return false;
1624 }
1625 }
1626 assert(num_annotations == calc_num_annotations, "sanity check");
1627
1628 return true;
1629 } // end rewrite_cp_refs_in_annotations_typeArray()
1630
1631
1632 // Rewrite constant pool references in the annotation struct portion of
1633 // an annotations_typeArray. This "structure" is from section 4.8.15 of
1634 // the 2nd-edition of the VM spec:
1635 //
1636 // struct annotation {
1637 // u2 type_index;
1638 // u2 num_element_value_pairs;
1639 // {
1640 // u2 element_name_index;
1641 // element_value value;
1642 // } element_value_pairs[num_element_value_pairs];
1643 // }
1644 //
1645 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct(
1646 typeArrayHandle annotations_typeArray, int &byte_i_ref, TRAPS) {
1647 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) {
1648 // not enough room for smallest annotation_struct
1649 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1650 ("length() is too small for annotation_struct"));
1651 return false;
1652 }
1653
1654 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray,
1655 byte_i_ref, "mapped old type_index=%d", THREAD);
1656
1657 u2 num_element_value_pairs = Bytes::get_Java_u2((address)
1658 annotations_typeArray->byte_at_addr(
1659 byte_i_ref));
1660 byte_i_ref += 2;
1661
1662 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1663 ("type_index=%d num_element_value_pairs=%d", type_index,
1664 num_element_value_pairs));
1665
1666 int calc_num_element_value_pairs = 0;
1667 for (; calc_num_element_value_pairs < num_element_value_pairs;
1668 calc_num_element_value_pairs++) {
1669 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1670 // not enough room for another element_name_index, let alone
1671 // the rest of another component
1672 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1673 ("length() is too small for element_name_index"));
1674 return false;
1675 }
1676
1677 u2 element_name_index = rewrite_cp_ref_in_annotation_data(
1678 annotations_typeArray, byte_i_ref,
1679 "mapped old element_name_index=%d", THREAD);
1680
1681 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1682 ("element_name_index=%d", element_name_index));
1683
1684 if (!rewrite_cp_refs_in_element_value(annotations_typeArray,
1685 byte_i_ref, THREAD)) {
1686 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1687 ("bad element_value at %d", calc_num_element_value_pairs));
1688 // propagate failure back to caller
1689 return false;
1690 }
1691 } // end for each component
1692 assert(num_element_value_pairs == calc_num_element_value_pairs,
1693 "sanity check");
1694
1695 return true;
1696 } // end rewrite_cp_refs_in_annotation_struct()
1697
1698
1699 // Rewrite a constant pool reference at the current position in
1700 // annotations_typeArray if needed. Returns the original constant
1701 // pool reference if a rewrite was not needed or the new constant
1702 // pool reference if a rewrite was needed.
1703 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data(
1704 typeArrayHandle annotations_typeArray, int &byte_i_ref,
1705 const char * trace_mesg, TRAPS) {
1706
1707 address cp_index_addr = (address)
1708 annotations_typeArray->byte_at_addr(byte_i_ref);
1709 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr);
1710 u2 new_cp_index = find_new_index(old_cp_index);
1711 if (new_cp_index != 0) {
1712 RC_TRACE_WITH_THREAD(0x02000000, THREAD, (trace_mesg, old_cp_index));
1713 Bytes::put_Java_u2(cp_index_addr, new_cp_index);
1714 old_cp_index = new_cp_index;
1715 }
1716 byte_i_ref += 2;
1717 return old_cp_index;
1718 }
1719
1720
1721 // Rewrite constant pool references in the element_value portion of an
1722 // annotations_typeArray. This "structure" is from section 4.8.15.1 of
1723 // the 2nd-edition of the VM spec:
1724 //
1725 // struct element_value {
1726 // u1 tag;
1727 // union {
1728 // u2 const_value_index;
1729 // {
1730 // u2 type_name_index;
1731 // u2 const_name_index;
1732 // } enum_const_value;
1733 // u2 class_info_index;
1734 // annotation annotation_value;
1735 // struct {
1736 // u2 num_values;
1737 // element_value values[num_values];
1738 // } array_value;
1739 // } value;
1740 // }
1741 //
1742 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value(
1743 typeArrayHandle annotations_typeArray, int &byte_i_ref, TRAPS) {
1744
1745 if ((byte_i_ref + 1) > annotations_typeArray->length()) {
1746 // not enough room for a tag let alone the rest of an element_value
1747 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1748 ("length() is too small for a tag"));
1749 return false;
1750 }
1751
1752 u1 tag = annotations_typeArray->byte_at(byte_i_ref);
1753 byte_i_ref++;
1754 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("tag='%c'", tag));
1755
1756 switch (tag) {
1757 // These BaseType tag values are from Table 4.2 in VM spec:
1758 case 'B': // byte
1759 case 'C': // char
1760 case 'D': // double
1761 case 'F': // float
1762 case 'I': // int
1763 case 'J': // long
1764 case 'S': // short
1765 case 'Z': // boolean
1766
1767 // The remaining tag values are from Table 4.8 in the 2nd-edition of
1768 // the VM spec:
1769 case 's':
1770 {
1771 // For the above tag values (including the BaseType values),
1772 // value.const_value_index is right union field.
1773
1774 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1775 // not enough room for a const_value_index
1776 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1777 ("length() is too small for a const_value_index"));
1778 return false;
1779 }
1780
1781 u2 const_value_index = rewrite_cp_ref_in_annotation_data(
1782 annotations_typeArray, byte_i_ref,
1783 "mapped old const_value_index=%d", THREAD);
1784
1785 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1786 ("const_value_index=%d", const_value_index));
1787 } break;
1788
1789 case 'e':
1790 {
1791 // for the above tag value, value.enum_const_value is right union field
1792
1793 if ((byte_i_ref + 4) > annotations_typeArray->length()) {
1794 // not enough room for a enum_const_value
1795 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1796 ("length() is too small for a enum_const_value"));
1797 return false;
1798 }
1799
1800 u2 type_name_index = rewrite_cp_ref_in_annotation_data(
1801 annotations_typeArray, byte_i_ref,
1802 "mapped old type_name_index=%d", THREAD);
1803
1804 u2 const_name_index = rewrite_cp_ref_in_annotation_data(
1805 annotations_typeArray, byte_i_ref,
1806 "mapped old const_name_index=%d", THREAD);
1807
1808 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1809 ("type_name_index=%d const_name_index=%d", type_name_index,
1810 const_name_index));
1811 } break;
1812
1813 case 'c':
1814 {
1815 // for the above tag value, value.class_info_index is right union field
1816
1817 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1818 // not enough room for a class_info_index
1819 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1820 ("length() is too small for a class_info_index"));
1821 return false;
1822 }
1823
1824 u2 class_info_index = rewrite_cp_ref_in_annotation_data(
1825 annotations_typeArray, byte_i_ref,
1826 "mapped old class_info_index=%d", THREAD);
1827
1828 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1829 ("class_info_index=%d", class_info_index));
1830 } break;
1831
1832 case '@':
1833 // For the above tag value, value.attr_value is the right union
1834 // field. This is a nested annotation.
1835 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
1836 byte_i_ref, THREAD)) {
1837 // propagate failure back to caller
1838 return false;
1839 }
1840 break;
1841
1842 case '[':
1843 {
1844 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1845 // not enough room for a num_values field
1846 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1847 ("length() is too small for a num_values field"));
1848 return false;
1849 }
1850
1851 // For the above tag value, value.array_value is the right union
1852 // field. This is an array of nested element_value.
1853 u2 num_values = Bytes::get_Java_u2((address)
1854 annotations_typeArray->byte_at_addr(byte_i_ref));
1855 byte_i_ref += 2;
1856 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("num_values=%d", num_values));
1857
1858 int calc_num_values = 0;
1859 for (; calc_num_values < num_values; calc_num_values++) {
1860 if (!rewrite_cp_refs_in_element_value(
1861 annotations_typeArray, byte_i_ref, THREAD)) {
1862 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1863 ("bad nested element_value at %d", calc_num_values));
1864 // propagate failure back to caller
1865 return false;
1866 }
1867 }
1868 assert(num_values == calc_num_values, "sanity check");
1869 } break;
1870
1871 default:
1872 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("bad tag=0x%x", tag));
1873 return false;
1874 } // end decode tag field
1875
1876 return true;
1877 } // end rewrite_cp_refs_in_element_value()
1878
1879
1880 // Rewrite constant pool references in a fields_annotations field.
1881 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations(
1882 instanceKlassHandle scratch_class, TRAPS) {
1883
1884 objArrayHandle fields_annotations(THREAD,
1885 scratch_class->fields_annotations());
1886
1887 if (fields_annotations.is_null() || fields_annotations->length() == 0) {
1888 // no fields_annotations so nothing to do
1889 return true;
1890 }
1891
1892 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1893 ("fields_annotations length=%d", fields_annotations->length()));
1894
1895 for (int i = 0; i < fields_annotations->length(); i++) {
1896 typeArrayHandle field_annotations(THREAD,
1897 (typeArrayOop)fields_annotations->obj_at(i));
1898 if (field_annotations.is_null() || field_annotations->length() == 0) {
1899 // this field does not have any annotations so skip it
1900 continue;
1901 }
1902
1903 int byte_i = 0; // byte index into field_annotations
1904 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i,
1905 THREAD)) {
1906 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1907 ("bad field_annotations at %d", i));
1908 // propagate failure back to caller
1909 return false;
1910 }
1911 }
1912
1913 return true;
1914 } // end rewrite_cp_refs_in_fields_annotations()
1915
1916
1917 // Rewrite constant pool references in a methods_annotations field.
1918 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations(
1919 instanceKlassHandle scratch_class, TRAPS) {
1920
1921 objArrayHandle methods_annotations(THREAD,
1922 scratch_class->methods_annotations());
1923
1924 if (methods_annotations.is_null() || methods_annotations->length() == 0) {
1925 // no methods_annotations so nothing to do
1926 return true;
1927 }
1928
1929 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1930 ("methods_annotations length=%d", methods_annotations->length()));
1931
1932 for (int i = 0; i < methods_annotations->length(); i++) {
1933 typeArrayHandle method_annotations(THREAD,
1934 (typeArrayOop)methods_annotations->obj_at(i));
1935 if (method_annotations.is_null() || method_annotations->length() == 0) {
1936 // this method does not have any annotations so skip it
1937 continue;
1938 }
1939
1940 int byte_i = 0; // byte index into method_annotations
1941 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i,
1942 THREAD)) {
1943 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1944 ("bad method_annotations at %d", i));
1945 // propagate failure back to caller
1946 return false;
1947 }
1948 }
1949
1950 return true;
1951 } // end rewrite_cp_refs_in_methods_annotations()
1952
1953
1954 // Rewrite constant pool references in a methods_parameter_annotations
1955 // field. This "structure" is adapted from the
1956 // RuntimeVisibleParameterAnnotations_attribute described in section
1957 // 4.8.17 of the 2nd-edition of the VM spec:
1958 //
1959 // methods_parameter_annotations_typeArray {
1960 // u1 num_parameters;
1961 // {
1962 // u2 num_annotations;
1963 // annotation annotations[num_annotations];
1964 // } parameter_annotations[num_parameters];
1965 // }
1966 //
1967 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations(
1968 instanceKlassHandle scratch_class, TRAPS) {
1969
1970 objArrayHandle methods_parameter_annotations(THREAD,
1971 scratch_class->methods_parameter_annotations());
1972
1973 if (methods_parameter_annotations.is_null()
1974 || methods_parameter_annotations->length() == 0) {
1975 // no methods_parameter_annotations so nothing to do
1976 return true;
1977 }
1978
1979 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1980 ("methods_parameter_annotations length=%d",
1981 methods_parameter_annotations->length()));
1982
1983 for (int i = 0; i < methods_parameter_annotations->length(); i++) {
1984 typeArrayHandle method_parameter_annotations(THREAD,
1985 (typeArrayOop)methods_parameter_annotations->obj_at(i));
1986 if (method_parameter_annotations.is_null()
1987 || method_parameter_annotations->length() == 0) {
1988 // this method does not have any parameter annotations so skip it
1989 continue;
1990 }
1991
1992 if (method_parameter_annotations->length() < 1) {
1993 // not enough room for a num_parameters field
1994 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1995 ("length() is too small for a num_parameters field at %d", i));
1996 return false;
1997 }
1998
1999 int byte_i = 0; // byte index into method_parameter_annotations
2000
2001 u1 num_parameters = method_parameter_annotations->byte_at(byte_i);
2002 byte_i++;
2003
2004 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2005 ("num_parameters=%d", num_parameters));
2006
2007 int calc_num_parameters = 0;
2008 for (; calc_num_parameters < num_parameters; calc_num_parameters++) {
2009 if (!rewrite_cp_refs_in_annotations_typeArray(
2010 method_parameter_annotations, byte_i, THREAD)) {
2011 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2012 ("bad method_parameter_annotations at %d", calc_num_parameters));
2013 // propagate failure back to caller
2014 return false;
2015 }
2016 }
2017 assert(num_parameters == calc_num_parameters, "sanity check");
2018 }
2019
2020 return true;
2021 } // end rewrite_cp_refs_in_methods_parameter_annotations()
2022
2023
2024 // Rewrite constant pool references in a methods_default_annotations
2025 // field. This "structure" is adapted from the AnnotationDefault_attribute
2026 // that is described in section 4.8.19 of the 2nd-edition of the VM spec:
2027 //
2028 // methods_default_annotations_typeArray {
2029 // element_value default_value;
2030 // }
2031 //
2032 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations(
2033 instanceKlassHandle scratch_class, TRAPS) {
2034
2035 objArrayHandle methods_default_annotations(THREAD,
2036 scratch_class->methods_default_annotations());
2037
2038 if (methods_default_annotations.is_null()
2039 || methods_default_annotations->length() == 0) {
2040 // no methods_default_annotations so nothing to do
2041 return true;
2042 }
2043
2044 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2045 ("methods_default_annotations length=%d",
2046 methods_default_annotations->length()));
2047
2048 for (int i = 0; i < methods_default_annotations->length(); i++) {
2049 typeArrayHandle method_default_annotations(THREAD,
2050 (typeArrayOop)methods_default_annotations->obj_at(i));
2051 if (method_default_annotations.is_null()
2052 || method_default_annotations->length() == 0) {
2053 // this method does not have any default annotations so skip it
2054 continue;
2055 }
2056
2057 int byte_i = 0; // byte index into method_default_annotations
2058
2059 if (!rewrite_cp_refs_in_element_value(
2060 method_default_annotations, byte_i, THREAD)) {
2061 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2062 ("bad default element_value at %d", i));
2063 // propagate failure back to caller
2064 return false;
2065 }
2066 }
2067
2068 return true;
2069 } // end rewrite_cp_refs_in_methods_default_annotations()
2070
2071
2072 // Rewrite constant pool references in the method's stackmap table.
2073 // These "structures" are adapted from the StackMapTable_attribute that
2074 // is described in section 4.8.4 of the 6.0 version of the VM spec
2075 // (dated 2005.10.26):
2076 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2077 //
2078 // stack_map {
2079 // u2 number_of_entries;
2080 // stack_map_frame entries[number_of_entries];
2081 // }
2082 //
2083 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table(
2084 methodHandle method, TRAPS) {
2085
2086 if (!method->has_stackmap_table()) {
2087 return;
2088 }
2089
2090 typeArrayOop stackmap_data = method->stackmap_data();
2091 address stackmap_p = (address)stackmap_data->byte_at_addr(0);
2092 address stackmap_end = stackmap_p + stackmap_data->length();
2093
2094 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries");
2095 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p);
2096 stackmap_p += 2;
2097
2098 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2099 ("number_of_entries=%u", number_of_entries));
2100
2101 // walk through each stack_map_frame
2102 u2 calc_number_of_entries = 0;
2103 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) {
2104 // The stack_map_frame structure is a u1 frame_type followed by
2105 // 0 or more bytes of data:
2106 //
2107 // union stack_map_frame {
2108 // same_frame;
2109 // same_locals_1_stack_item_frame;
2110 // same_locals_1_stack_item_frame_extended;
2111 // chop_frame;
2112 // same_frame_extended;
2113 // append_frame;
2114 // full_frame;
2115 // }
2116
2117 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type");
2118 // The Linux compiler does not like frame_type to be u1 or u2. It
2119 // issues the following warning for the first if-statement below:
2120 //
2121 // "warning: comparison is always true due to limited range of data type"
2122 //
2123 u4 frame_type = *stackmap_p;
2124 stackmap_p++;
2125
2126 // same_frame {
2127 // u1 frame_type = SAME; /* 0-63 */
2128 // }
2129 if (frame_type >= 0 && frame_type <= 63) {
2130 // nothing more to do for same_frame
2131 }
2132
2133 // same_locals_1_stack_item_frame {
2134 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */
2135 // verification_type_info stack[1];
2136 // }
2137 else if (frame_type >= 64 && frame_type <= 127) {
2138 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2139 calc_number_of_entries, frame_type, THREAD);
2140 }
2141
2142 // reserved for future use
2143 else if (frame_type >= 128 && frame_type <= 246) {
2144 // nothing more to do for reserved frame_types
2145 }
2146
2147 // same_locals_1_stack_item_frame_extended {
2148 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */
2149 // u2 offset_delta;
2150 // verification_type_info stack[1];
2151 // }
2152 else if (frame_type == 247) {
2153 stackmap_p += 2;
2154 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2155 calc_number_of_entries, frame_type, THREAD);
2156 }
2157
2158 // chop_frame {
2159 // u1 frame_type = CHOP; /* 248-250 */
2160 // u2 offset_delta;
2161 // }
2162 else if (frame_type >= 248 && frame_type <= 250) {
2163 stackmap_p += 2;
2164 }
2165
2166 // same_frame_extended {
2167 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/
2168 // u2 offset_delta;
2169 // }
2170 else if (frame_type == 251) {
2171 stackmap_p += 2;
2172 }
2173
2174 // append_frame {
2175 // u1 frame_type = APPEND; /* 252-254 */
2176 // u2 offset_delta;
2177 // verification_type_info locals[frame_type - 251];
2178 // }
2179 else if (frame_type >= 252 && frame_type <= 254) {
2180 assert(stackmap_p + 2 <= stackmap_end,
2181 "no room for offset_delta");
2182 stackmap_p += 2;
2183 u1 len = frame_type - 251;
2184 for (u1 i = 0; i < len; i++) {
2185 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2186 calc_number_of_entries, frame_type, THREAD);
2187 }
2188 }
2189
2190 // full_frame {
2191 // u1 frame_type = FULL_FRAME; /* 255 */
2192 // u2 offset_delta;
2193 // u2 number_of_locals;
2194 // verification_type_info locals[number_of_locals];
2195 // u2 number_of_stack_items;
2196 // verification_type_info stack[number_of_stack_items];
2197 // }
2198 else if (frame_type == 255) {
2199 assert(stackmap_p + 2 + 2 <= stackmap_end,
2200 "no room for smallest full_frame");
2201 stackmap_p += 2;
2202
2203 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p);
2204 stackmap_p += 2;
2205
2206 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) {
2207 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2208 calc_number_of_entries, frame_type, THREAD);
2209 }
2210
2211 // Use the largest size for the number_of_stack_items, but only get
2212 // the right number of bytes.
2213 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p);
2214 stackmap_p += 2;
2215
2216 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) {
2217 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2218 calc_number_of_entries, frame_type, THREAD);
2219 }
2220 }
2221 } // end while there is a stack_map_frame
2222 assert(number_of_entries == calc_number_of_entries, "sanity check");
2223 } // end rewrite_cp_refs_in_stack_map_table()
2224
2225
2226 // Rewrite constant pool references in the verification type info
2227 // portion of the method's stackmap table. These "structures" are
2228 // adapted from the StackMapTable_attribute that is described in
2229 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26):
2230 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2231 //
2232 // The verification_type_info structure is a u1 tag followed by 0 or
2233 // more bytes of data:
2234 //
2235 // union verification_type_info {
2236 // Top_variable_info;
2237 // Integer_variable_info;
2238 // Float_variable_info;
2239 // Long_variable_info;
2240 // Double_variable_info;
2241 // Null_variable_info;
2242 // UninitializedThis_variable_info;
2243 // Object_variable_info;
2244 // Uninitialized_variable_info;
2245 // }
2246 //
2247 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info(
2248 address& stackmap_p_ref, address stackmap_end, u2 frame_i,
2249 u1 frame_type, TRAPS) {
2250
2251 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag");
2252 u1 tag = *stackmap_p_ref;
2253 stackmap_p_ref++;
2254
2255 switch (tag) {
2256 // Top_variable_info {
2257 // u1 tag = ITEM_Top; /* 0 */
2258 // }
2259 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top
2260 case 0: // fall through
2261
2262 // Integer_variable_info {
2263 // u1 tag = ITEM_Integer; /* 1 */
2264 // }
2265 case ITEM_Integer: // fall through
2266
2267 // Float_variable_info {
2268 // u1 tag = ITEM_Float; /* 2 */
2269 // }
2270 case ITEM_Float: // fall through
2271
2272 // Double_variable_info {
2273 // u1 tag = ITEM_Double; /* 3 */
2274 // }
2275 case ITEM_Double: // fall through
2276
2277 // Long_variable_info {
2278 // u1 tag = ITEM_Long; /* 4 */
2279 // }
2280 case ITEM_Long: // fall through
2281
2282 // Null_variable_info {
2283 // u1 tag = ITEM_Null; /* 5 */
2284 // }
2285 case ITEM_Null: // fall through
2286
2287 // UninitializedThis_variable_info {
2288 // u1 tag = ITEM_UninitializedThis; /* 6 */
2289 // }
2290 case ITEM_UninitializedThis:
2291 // nothing more to do for the above tag types
2292 break;
2293
2294 // Object_variable_info {
2295 // u1 tag = ITEM_Object; /* 7 */
2296 // u2 cpool_index;
2297 // }
2298 case ITEM_Object:
2299 {
2300 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index");
2301 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref);
2302 u2 new_cp_index = find_new_index(cpool_index);
2303 if (new_cp_index != 0) {
2304 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2305 ("mapped old cpool_index=%d", cpool_index));
2306 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
2307 cpool_index = new_cp_index;
2308 }
2309 stackmap_p_ref += 2;
2310
2311 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2312 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i,
2313 frame_type, cpool_index));
2314 } break;
2315
2316 // Uninitialized_variable_info {
2317 // u1 tag = ITEM_Uninitialized; /* 8 */
2318 // u2 offset;
2319 // }
2320 case ITEM_Uninitialized:
2321 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset");
2322 stackmap_p_ref += 2;
2323 break;
2324
2325 default:
2326 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2327 ("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag));
2328 ShouldNotReachHere();
2329 break;
2330 } // end switch (tag)
2331 } // end rewrite_cp_refs_in_verification_type_info()
2332
2333
2334 // Change the constant pool associated with klass scratch_class to
2335 // scratch_cp. If shrink is true, then scratch_cp_length elements
2336 // are copied from scratch_cp to a smaller constant pool and the
2337 // smaller constant pool is associated with scratch_class.
2338 void VM_RedefineClasses::set_new_constant_pool(
2339 instanceKlassHandle scratch_class, constantPoolHandle scratch_cp,
2340 int scratch_cp_length, bool shrink, TRAPS) {
2341 assert(!shrink || scratch_cp->length() >= scratch_cp_length, "sanity check");
2342
2343 if (shrink) {
2344 // scratch_cp is a merged constant pool and has enough space for a
2345 // worst case merge situation. We want to associate the minimum
2346 // sized constant pool with the klass to save space.
2347 constantPoolHandle smaller_cp(THREAD,
2348 oopFactory::new_constantPool(scratch_cp_length,
2349 oopDesc::IsUnsafeConc,
2350 THREAD));
2351 // preserve orig_length() value in the smaller copy
2352 int orig_length = scratch_cp->orig_length();
2353 assert(orig_length != 0, "sanity check");
2354 smaller_cp->set_orig_length(orig_length);
2355 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
2356 scratch_cp = smaller_cp;
2357 smaller_cp()->set_is_conc_safe(true);
2358 }
2359
2360 // attach new constant pool to klass
2361 scratch_cp->set_pool_holder(scratch_class());
2362
2363 // attach klass to new constant pool
2364 scratch_class->set_constants(scratch_cp());
2365
2366 int i; // for portability
2367
2368 // update each field in klass to use new constant pool indices as needed
2369 typeArrayHandle fields(THREAD, scratch_class->fields());
2370 int n_fields = fields->length();
2371 for (i = 0; i < n_fields; i += instanceKlass::next_offset) {
2372 jshort cur_index = fields->short_at(i + instanceKlass::name_index_offset);
2373 jshort new_index = find_new_index(cur_index);
2374 if (new_index != 0) {
2375 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2376 ("field-name_index change: %d to %d", cur_index, new_index));
2377 fields->short_at_put(i + instanceKlass::name_index_offset, new_index);
2378 }
2379 cur_index = fields->short_at(i + instanceKlass::signature_index_offset);
2380 new_index = find_new_index(cur_index);
2381 if (new_index != 0) {
2382 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2383 ("field-signature_index change: %d to %d", cur_index, new_index));
2384 fields->short_at_put(i + instanceKlass::signature_index_offset,
2385 new_index);
2386 }
2387 cur_index = fields->short_at(i + instanceKlass::initval_index_offset);
2388 new_index = find_new_index(cur_index);
2389 if (new_index != 0) {
2390 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2391 ("field-initval_index change: %d to %d", cur_index, new_index));
2392 fields->short_at_put(i + instanceKlass::initval_index_offset, new_index);
2393 }
2394 cur_index = fields->short_at(i + instanceKlass::generic_signature_offset);
2395 new_index = find_new_index(cur_index);
2396 if (new_index != 0) {
2397 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2398 ("field-generic_signature change: %d to %d", cur_index, new_index));
2399 fields->short_at_put(i + instanceKlass::generic_signature_offset,
2400 new_index);
2401 }
2402 } // end for each field
2403
2404 // Update constant pool indices in the inner classes info to use
2405 // new constant indices as needed. The inner classes info is a
2406 // quadruple:
2407 // (inner_class_info, outer_class_info, inner_name, inner_access_flags)
2408 typeArrayOop inner_class_list = scratch_class->inner_classes();
2409 int icl_length = (inner_class_list == NULL) ? 0 : inner_class_list->length();
2410 if (icl_length > 0) {
2411 typeArrayHandle inner_class_list_h(THREAD, inner_class_list);
2412 for (int i = 0; i < icl_length;
2413 i += instanceKlass::inner_class_next_offset) {
2414 int cur_index = inner_class_list_h->ushort_at(i
2415 + instanceKlass::inner_class_inner_class_info_offset);
2416 if (cur_index == 0) {
2417 continue; // JVM spec. allows null inner class refs so skip it
2418 }
2419 int new_index = find_new_index(cur_index);
2420 if (new_index != 0) {
2421 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2422 ("inner_class_info change: %d to %d", cur_index, new_index));
2423 inner_class_list_h->ushort_at_put(i
2424 + instanceKlass::inner_class_inner_class_info_offset, new_index);
2425 }
2426 cur_index = inner_class_list_h->ushort_at(i
2427 + instanceKlass::inner_class_outer_class_info_offset);
2428 new_index = find_new_index(cur_index);
2429 if (new_index != 0) {
2430 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2431 ("outer_class_info change: %d to %d", cur_index, new_index));
2432 inner_class_list_h->ushort_at_put(i
2433 + instanceKlass::inner_class_outer_class_info_offset, new_index);
2434 }
2435 cur_index = inner_class_list_h->ushort_at(i
2436 + instanceKlass::inner_class_inner_name_offset);
2437 new_index = find_new_index(cur_index);
2438 if (new_index != 0) {
2439 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2440 ("inner_name change: %d to %d", cur_index, new_index));
2441 inner_class_list_h->ushort_at_put(i
2442 + instanceKlass::inner_class_inner_name_offset, new_index);
2443 }
2444 } // end for each inner class
2445 } // end if we have inner classes
2446
2447 // Attach each method in klass to the new constant pool and update
2448 // to use new constant pool indices as needed:
2449 objArrayHandle methods(THREAD, scratch_class->methods());
2450 for (i = methods->length() - 1; i >= 0; i--) {
2451 methodHandle method(THREAD, (methodOop)methods->obj_at(i));
2452 method->set_constants(scratch_cp());
2453
2454 int new_index = find_new_index(method->name_index());
2455 if (new_index != 0) {
2456 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2457 ("method-name_index change: %d to %d", method->name_index(),
2458 new_index));
2459 method->set_name_index(new_index);
2460 }
2461 new_index = find_new_index(method->signature_index());
2462 if (new_index != 0) {
2463 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2464 ("method-signature_index change: %d to %d",
2465 method->signature_index(), new_index));
2466 method->set_signature_index(new_index);
2467 }
2468 new_index = find_new_index(method->generic_signature_index());
2469 if (new_index != 0) {
2470 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2471 ("method-generic_signature_index change: %d to %d",
2472 method->generic_signature_index(), new_index));
2473 method->set_generic_signature_index(new_index);
2474 }
2475
2476 // Update constant pool indices in the method's checked exception
2477 // table to use new constant indices as needed.
2478 int cext_length = method->checked_exceptions_length();
2479 if (cext_length > 0) {
2480 CheckedExceptionElement * cext_table =
2481 method->checked_exceptions_start();
2482 for (int j = 0; j < cext_length; j++) {
2483 int cur_index = cext_table[j].class_cp_index;
2484 int new_index = find_new_index(cur_index);
2485 if (new_index != 0) {
2486 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2487 ("cext-class_cp_index change: %d to %d", cur_index, new_index));
2488 cext_table[j].class_cp_index = (u2)new_index;
2489 }
2490 } // end for each checked exception table entry
2491 } // end if there are checked exception table entries
2492
2493 // Update each catch type index in the method's exception table
2494 // to use new constant pool indices as needed. The exception table
2495 // holds quadruple entries of the form:
2496 // (beg_bci, end_bci, handler_bci, klass_index)
2497 const int beg_bci_offset = 0;
2498 const int end_bci_offset = 1;
2499 const int handler_bci_offset = 2;
2500 const int klass_index_offset = 3;
2501 const int entry_size = 4;
2502
2503 typeArrayHandle ex_table (THREAD, method->exception_table());
2504 int ext_length = ex_table->length();
2505 assert(ext_length % entry_size == 0, "exception table format has changed");
2506
2507 for (int j = 0; j < ext_length; j += entry_size) {
2508 int cur_index = ex_table->int_at(j + klass_index_offset);
2509 int new_index = find_new_index(cur_index);
2510 if (new_index != 0) {
2511 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2512 ("ext-klass_index change: %d to %d", cur_index, new_index));
2513 ex_table->int_at_put(j + klass_index_offset, new_index);
2514 }
2515 } // end for each exception table entry
2516
2517 // Update constant pool indices in the method's local variable
2518 // table to use new constant indices as needed. The local variable
2519 // table hold sextuple entries of the form:
2520 // (start_pc, length, name_index, descriptor_index, signature_index, slot)
2521 int lvt_length = method->localvariable_table_length();
2522 if (lvt_length > 0) {
2523 LocalVariableTableElement * lv_table =
2524 method->localvariable_table_start();
2525 for (int j = 0; j < lvt_length; j++) {
2526 int cur_index = lv_table[j].name_cp_index;
2527 int new_index = find_new_index(cur_index);
2528 if (new_index != 0) {
2529 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2530 ("lvt-name_cp_index change: %d to %d", cur_index, new_index));
2531 lv_table[j].name_cp_index = (u2)new_index;
2532 }
2533 cur_index = lv_table[j].descriptor_cp_index;
2534 new_index = find_new_index(cur_index);
2535 if (new_index != 0) {
2536 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2537 ("lvt-descriptor_cp_index change: %d to %d", cur_index,
2538 new_index));
2539 lv_table[j].descriptor_cp_index = (u2)new_index;
2540 }
2541 cur_index = lv_table[j].signature_cp_index;
2542 new_index = find_new_index(cur_index);
2543 if (new_index != 0) {
2544 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2545 ("lvt-signature_cp_index change: %d to %d", cur_index, new_index));
2546 lv_table[j].signature_cp_index = (u2)new_index;
2547 }
2548 } // end for each local variable table entry
2549 } // end if there are local variable table entries
2550
2551 rewrite_cp_refs_in_stack_map_table(method, THREAD);
2552 } // end for each method
2553 assert(scratch_cp()->is_conc_safe(), "Just checking");
2554 } // end set_new_constant_pool()
2555
2556
2557 // Unevolving classes may point to methods of the_class directly
2558 // from their constant pool caches, itables, and/or vtables. We
2559 // use the SystemDictionary::classes_do() facility and this helper
2560 // to fix up these pointers.
2561 //
2562 // Note: We currently don't support updating the vtable in
2563 // arrayKlassOops. See Open Issues in jvmtiRedefineClasses.hpp.
2564 void VM_RedefineClasses::adjust_cpool_cache_and_vtable(klassOop k_oop,
2565 oop initiating_loader, TRAPS) {
2566 Klass *k = k_oop->klass_part();
2567 if (k->oop_is_instance()) {
2568 HandleMark hm(THREAD);
2569 instanceKlass *ik = (instanceKlass *) k;
2570
2571 // HotSpot specific optimization! HotSpot does not currently
2572 // support delegation from the bootstrap class loader to a
2573 // user-defined class loader. This means that if the bootstrap
2574 // class loader is the initiating class loader, then it will also
2575 // be the defining class loader. This also means that classes
2576 // loaded by the bootstrap class loader cannot refer to classes
2577 // loaded by a user-defined class loader. Note: a user-defined
2578 // class loader can delegate to the bootstrap class loader.
2579 //
2580 // If the current class being redefined has a user-defined class
2581 // loader as its defining class loader, then we can skip all
2582 // classes loaded by the bootstrap class loader.
2583 bool is_user_defined =
2584 instanceKlass::cast(_the_class_oop)->class_loader() != NULL;
2585 if (is_user_defined && ik->class_loader() == NULL) {
2586 return;
2587 }
2588
2589 // This is a very busy routine. We don't want too much tracing
2590 // printed out.
2591 bool trace_name_printed = false;
2592
2593 // Very noisy: only enable this call if you are trying to determine
2594 // that a specific class gets found by this routine.
2595 // RC_TRACE macro has an embedded ResourceMark
2596 // RC_TRACE_WITH_THREAD(0x00100000, THREAD,
2597 // ("adjust check: name=%s", ik->external_name()));
2598 // trace_name_printed = true;
2599
2600 // Fix the vtable embedded in the_class and subclasses of the_class,
2601 // if one exists. We discard scratch_class and we don't keep an
2602 // instanceKlass around to hold obsolete methods so we don't have
2603 // any other instanceKlass embedded vtables to update. The vtable
2604 // holds the methodOops for virtual (but not final) methods.
2605 if (ik->vtable_length() > 0 && ik->is_subtype_of(_the_class_oop)) {
2606 // ik->vtable() creates a wrapper object; rm cleans it up
2607 ResourceMark rm(THREAD);
2608 ik->vtable()->adjust_method_entries(_matching_old_methods,
2609 _matching_new_methods,
2610 _matching_methods_length,
2611 &trace_name_printed);
2612 }
2613
2614 // If the current class has an itable and we are either redefining an
2615 // interface or if the current class is a subclass of the_class, then
2616 // we potentially have to fix the itable. If we are redefining an
2617 // interface, then we have to call adjust_method_entries() for
2618 // every instanceKlass that has an itable since there isn't a
2619 // subclass relationship between an interface and an instanceKlass.
2620 if (ik->itable_length() > 0 && (Klass::cast(_the_class_oop)->is_interface()
2621 || ik->is_subclass_of(_the_class_oop))) {
2622 // ik->itable() creates a wrapper object; rm cleans it up
2623 ResourceMark rm(THREAD);
2624 ik->itable()->adjust_method_entries(_matching_old_methods,
2625 _matching_new_methods,
2626 _matching_methods_length,
2627 &trace_name_printed);
2628 }
2629
2630 // The constant pools in other classes (other_cp) can refer to
2631 // methods in the_class. We have to update method information in
2632 // other_cp's cache. If other_cp has a previous version, then we
2633 // have to repeat the process for each previous version. The
2634 // constant pool cache holds the methodOops for non-virtual
2635 // methods and for virtual, final methods.
2636 //
2637 // Special case: if the current class is the_class, then new_cp
2638 // has already been attached to the_class and old_cp has already
2639 // been added as a previous version. The new_cp doesn't have any
2640 // cached references to old methods so it doesn't need to be
2641 // updated. We can simply start with the previous version(s) in
2642 // that case.
2643 constantPoolHandle other_cp;
2644 constantPoolCacheOop cp_cache;
2645
2646 if (k_oop != _the_class_oop) {
2647 // this klass' constant pool cache may need adjustment
2648 other_cp = constantPoolHandle(ik->constants());
2649 cp_cache = other_cp->cache();
2650 if (cp_cache != NULL) {
2651 cp_cache->adjust_method_entries(_matching_old_methods,
2652 _matching_new_methods,
2653 _matching_methods_length,
2654 &trace_name_printed);
2655 }
2656 }
2657 {
2658 ResourceMark rm(THREAD);
2659 // PreviousVersionInfo objects returned via PreviousVersionWalker
2660 // contain a GrowableArray of handles. We have to clean up the
2661 // GrowableArray _after_ the PreviousVersionWalker destructor
2662 // has destroyed the handles.
2663 {
2664 // the previous versions' constant pool caches may need adjustment
2665 PreviousVersionWalker pvw(ik);
2666 for (PreviousVersionInfo * pv_info = pvw.next_previous_version();
2667 pv_info != NULL; pv_info = pvw.next_previous_version()) {
2668 other_cp = pv_info->prev_constant_pool_handle();
2669 cp_cache = other_cp->cache();
2670 if (cp_cache != NULL) {
2671 cp_cache->adjust_method_entries(_matching_old_methods,
2672 _matching_new_methods,
2673 _matching_methods_length,
2674 &trace_name_printed);
2675 }
2676 }
2677 } // pvw is cleaned up
2678 } // rm is cleaned up
2679 }
2680 }
2681
2682 void VM_RedefineClasses::update_jmethod_ids() {
2683 for (int j = 0; j < _matching_methods_length; ++j) {
2684 methodOop old_method = _matching_old_methods[j];
2685 jmethodID jmid = old_method->find_jmethod_id_or_null();
2686 if (jmid != NULL) {
2687 // There is a jmethodID, change it to point to the new method
2688 methodHandle new_method_h(_matching_new_methods[j]);
2689 JNIHandles::change_method_associated_with_jmethod_id(jmid, new_method_h);
2690 assert(JNIHandles::resolve_jmethod_id(jmid) == _matching_new_methods[j],
2691 "should be replaced");
2692 }
2693 }
2694 }
2695
2696 void VM_RedefineClasses::check_methods_and_mark_as_obsolete(
2697 BitMap *emcp_methods, int * emcp_method_count_p) {
2698 *emcp_method_count_p = 0;
2699 int obsolete_count = 0;
2700 int old_index = 0;
2701 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
2702 methodOop old_method = _matching_old_methods[j];
2703 methodOop new_method = _matching_new_methods[j];
2704 methodOop old_array_method;
2705
2706 // Maintain an old_index into the _old_methods array by skipping
2707 // deleted methods
2708 while ((old_array_method = (methodOop) _old_methods->obj_at(old_index))
2709 != old_method) {
2710 ++old_index;
2711 }
2712
2713 if (MethodComparator::methods_EMCP(old_method, new_method)) {
2714 // The EMCP definition from JSR-163 requires the bytecodes to be
2715 // the same with the exception of constant pool indices which may
2716 // differ. However, the constants referred to by those indices
2717 // must be the same.
2718 //
2719 // We use methods_EMCP() for comparison since constant pool
2720 // merging can remove duplicate constant pool entries that were
2721 // present in the old method and removed from the rewritten new
2722 // method. A faster binary comparison function would consider the
2723 // old and new methods to be different when they are actually
2724 // EMCP.
2725 //
2726 // The old and new methods are EMCP and you would think that we
2727 // could get rid of one of them here and now and save some space.
2728 // However, the concept of EMCP only considers the bytecodes and
2729 // the constant pool entries in the comparison. Other things,
2730 // e.g., the line number table (LNT) or the local variable table
2731 // (LVT) don't count in the comparison. So the new (and EMCP)
2732 // method can have a new LNT that we need so we can't just
2733 // overwrite the new method with the old method.
2734 //
2735 // When this routine is called, we have already attached the new
2736 // methods to the_class so the old methods are effectively
2737 // overwritten. However, if an old method is still executing,
2738 // then the old method cannot be collected until sometime after
2739 // the old method call has returned. So the overwriting of old
2740 // methods by new methods will save us space except for those
2741 // (hopefully few) old methods that are still executing.
2742 //
2743 // A method refers to a constMethodOop and this presents another
2744 // possible avenue to space savings. The constMethodOop in the
2745 // new method contains possibly new attributes (LNT, LVT, etc).
2746 // At first glance, it seems possible to save space by replacing
2747 // the constMethodOop in the old method with the constMethodOop
2748 // from the new method. The old and new methods would share the
2749 // same constMethodOop and we would save the space occupied by
2750 // the old constMethodOop. However, the constMethodOop contains
2751 // a back reference to the containing method. Sharing the
2752 // constMethodOop between two methods could lead to confusion in
2753 // the code that uses the back reference. This would lead to
2754 // brittle code that could be broken in non-obvious ways now or
2755 // in the future.
2756 //
2757 // Another possibility is to copy the constMethodOop from the new
2758 // method to the old method and then overwrite the new method with
2759 // the old method. Since the constMethodOop contains the bytecodes
2760 // for the method embedded in the oop, this option would change
2761 // the bytecodes out from under any threads executing the old
2762 // method and make the thread's bcp invalid. Since EMCP requires
2763 // that the bytecodes be the same modulo constant pool indices, it
2764 // is straight forward to compute the correct new bcp in the new
2765 // constMethodOop from the old bcp in the old constMethodOop. The
2766 // time consuming part would be searching all the frames in all
2767 // of the threads to find all of the calls to the old method.
2768 //
2769 // It looks like we will have to live with the limited savings
2770 // that we get from effectively overwriting the old methods
2771 // when the new methods are attached to the_class.
2772
2773 // track which methods are EMCP for add_previous_version() call
2774 emcp_methods->set_bit(old_index);
2775 (*emcp_method_count_p)++;
2776
2777 // An EMCP method is _not_ obsolete. An obsolete method has a
2778 // different jmethodID than the current method. An EMCP method
2779 // has the same jmethodID as the current method. Having the
2780 // same jmethodID for all EMCP versions of a method allows for
2781 // a consistent view of the EMCP methods regardless of which
2782 // EMCP method you happen to have in hand. For example, a
2783 // breakpoint set in one EMCP method will work for all EMCP
2784 // versions of the method including the current one.
2785 } else {
2786 // mark obsolete methods as such
2787 old_method->set_is_obsolete();
2788 obsolete_count++;
2789
2790 // obsolete methods need a unique idnum
2791 u2 num = instanceKlass::cast(_the_class_oop)->next_method_idnum();
2792 if (num != constMethodOopDesc::UNSET_IDNUM) {
2793 // u2 old_num = old_method->method_idnum();
2794 old_method->set_method_idnum(num);
2795 // TO DO: attach obsolete annotations to obsolete method's new idnum
2796 }
2797 // With tracing we try not to "yack" too much. The position of
2798 // this trace assumes there are fewer obsolete methods than
2799 // EMCP methods.
2800 RC_TRACE(0x00000100, ("mark %s(%s) as obsolete",
2801 old_method->name()->as_C_string(),
2802 old_method->signature()->as_C_string()));
2803 }
2804 old_method->set_is_old();
2805 }
2806 for (int i = 0; i < _deleted_methods_length; ++i) {
2807 methodOop old_method = _deleted_methods[i];
2808
2809 assert(old_method->vtable_index() < 0,
2810 "cannot delete methods with vtable entries");;
2811
2812 // Mark all deleted methods as old and obsolete
2813 old_method->set_is_old();
2814 old_method->set_is_obsolete();
2815 ++obsolete_count;
2816 // With tracing we try not to "yack" too much. The position of
2817 // this trace assumes there are fewer obsolete methods than
2818 // EMCP methods.
2819 RC_TRACE(0x00000100, ("mark deleted %s(%s) as obsolete",
2820 old_method->name()->as_C_string(),
2821 old_method->signature()->as_C_string()));
2822 }
2823 assert((*emcp_method_count_p + obsolete_count) == _old_methods->length(),
2824 "sanity check");
2825 RC_TRACE(0x00000100, ("EMCP_cnt=%d, obsolete_cnt=%d", *emcp_method_count_p,
2826 obsolete_count));
2827 }
2828
2829 // This internal class transfers the native function registration from old methods
2830 // to new methods. It is designed to handle both the simple case of unchanged
2831 // native methods and the complex cases of native method prefixes being added and/or
2832 // removed.
2833 // It expects only to be used during the VM_RedefineClasses op (a safepoint).
2834 //
2835 // This class is used after the new methods have been installed in "the_class".
2836 //
2837 // So, for example, the following must be handled. Where 'm' is a method and
2838 // a number followed by an underscore is a prefix.
2839 //
2840 // Old Name New Name
2841 // Simple transfer to new method m -> m
2842 // Add prefix m -> 1_m
2843 // Remove prefix 1_m -> m
2844 // Simultaneous add of prefixes m -> 3_2_1_m
2845 // Simultaneous removal of prefixes 3_2_1_m -> m
2846 // Simultaneous add and remove 1_m -> 2_m
2847 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m
2848 //
2849 class TransferNativeFunctionRegistration {
2850 private:
2851 instanceKlassHandle the_class;
2852 int prefix_count;
2853 char** prefixes;
2854
2855 // Recursively search the binary tree of possibly prefixed method names.
2856 // Iteration could be used if all agents were well behaved. Full tree walk is
2857 // more resilent to agents not cleaning up intermediate methods.
2858 // Branch at each depth in the binary tree is:
2859 // (1) without the prefix.
2860 // (2) with the prefix.
2861 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
2862 methodOop search_prefix_name_space(int depth, char* name_str, size_t name_len,
2863 Symbol* signature) {
2864 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len);
2865 if (name_symbol != NULL) {
2866 methodOop method = Klass::cast(the_class())->lookup_method(name_symbol, signature);
2867 if (method != NULL) {
2868 // Even if prefixed, intermediate methods must exist.
2869 if (method->is_native()) {
2870 // Wahoo, we found a (possibly prefixed) version of the method, return it.
2871 return method;
2872 }
2873 if (depth < prefix_count) {
2874 // Try applying further prefixes (other than this one).
2875 method = search_prefix_name_space(depth+1, name_str, name_len, signature);
2876 if (method != NULL) {
2877 return method; // found
2878 }
2879
2880 // Try adding this prefix to the method name and see if it matches
2881 // another method name.
2882 char* prefix = prefixes[depth];
2883 size_t prefix_len = strlen(prefix);
2884 size_t trial_len = name_len + prefix_len;
2885 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
2886 strcpy(trial_name_str, prefix);
2887 strcat(trial_name_str, name_str);
2888 method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
2889 signature);
2890 if (method != NULL) {
2891 // If found along this branch, it was prefixed, mark as such
2892 method->set_is_prefixed_native();
2893 return method; // found
2894 }
2895 }
2896 }
2897 }
2898 return NULL; // This whole branch bore nothing
2899 }
2900
2901 // Return the method name with old prefixes stripped away.
2902 char* method_name_without_prefixes(methodOop method) {
2903 Symbol* name = method->name();
2904 char* name_str = name->as_utf8();
2905
2906 // Old prefixing may be defunct, strip prefixes, if any.
2907 for (int i = prefix_count-1; i >= 0; i--) {
2908 char* prefix = prefixes[i];
2909 size_t prefix_len = strlen(prefix);
2910 if (strncmp(prefix, name_str, prefix_len) == 0) {
2911 name_str += prefix_len;
2912 }
2913 }
2914 return name_str;
2915 }
2916
2917 // Strip any prefixes off the old native method, then try to find a
2918 // (possibly prefixed) new native that matches it.
2919 methodOop strip_and_search_for_new_native(methodOop method) {
2920 ResourceMark rm;
2921 char* name_str = method_name_without_prefixes(method);
2922 return search_prefix_name_space(0, name_str, strlen(name_str),
2923 method->signature());
2924 }
2925
2926 public:
2927
2928 // Construct a native method transfer processor for this class.
2929 TransferNativeFunctionRegistration(instanceKlassHandle _the_class) {
2930 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
2931
2932 the_class = _the_class;
2933 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
2934 }
2935
2936 // Attempt to transfer any of the old or deleted methods that are native
2937 void transfer_registrations(methodOop* old_methods, int methods_length) {
2938 for (int j = 0; j < methods_length; j++) {
2939 methodOop old_method = old_methods[j];
2940
2941 if (old_method->is_native() && old_method->has_native_function()) {
2942 methodOop new_method = strip_and_search_for_new_native(old_method);
2943 if (new_method != NULL) {
2944 // Actually set the native function in the new method.
2945 // Redefine does not send events (except CFLH), certainly not this
2946 // behind the scenes re-registration.
2947 new_method->set_native_function(old_method->native_function(),
2948 !methodOopDesc::native_bind_event_is_interesting);
2949 }
2950 }
2951 }
2952 }
2953 };
2954
2955 // Don't lose the association between a native method and its JNI function.
2956 void VM_RedefineClasses::transfer_old_native_function_registrations(instanceKlassHandle the_class) {
2957 TransferNativeFunctionRegistration transfer(the_class);
2958 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length);
2959 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length);
2960 }
2961
2962 // Deoptimize all compiled code that depends on this class.
2963 //
2964 // If the can_redefine_classes capability is obtained in the onload
2965 // phase then the compiler has recorded all dependencies from startup.
2966 // In that case we need only deoptimize and throw away all compiled code
2967 // that depends on the class.
2968 //
2969 // If can_redefine_classes is obtained sometime after the onload
2970 // phase then the dependency information may be incomplete. In that case
2971 // the first call to RedefineClasses causes all compiled code to be
2972 // thrown away. As can_redefine_classes has been obtained then
2973 // all future compilations will record dependencies so second and
2974 // subsequent calls to RedefineClasses need only throw away code
2975 // that depends on the class.
2976 //
2977 void VM_RedefineClasses::flush_dependent_code(instanceKlassHandle k_h, TRAPS) {
2978 assert_locked_or_safepoint(Compile_lock);
2979
2980 // All dependencies have been recorded from startup or this is a second or
2981 // subsequent use of RedefineClasses
2982 if (JvmtiExport::all_dependencies_are_recorded()) {
2983 Universe::flush_evol_dependents_on(k_h);
2984 } else {
2985 CodeCache::mark_all_nmethods_for_deoptimization();
2986
2987 ResourceMark rm(THREAD);
2988 DeoptimizationMarker dm;
2989
2990 // Deoptimize all activations depending on marked nmethods
2991 Deoptimization::deoptimize_dependents();
2992
2993 // Make the dependent methods not entrant (in VM_Deoptimize they are made zombies)
2994 CodeCache::make_marked_nmethods_not_entrant();
2995
2996 // From now on we know that the dependency information is complete
2997 JvmtiExport::set_all_dependencies_are_recorded(true);
2998 }
2999 }
3000
3001 void VM_RedefineClasses::compute_added_deleted_matching_methods() {
3002 methodOop old_method;
3003 methodOop new_method;
3004
3005 _matching_old_methods = NEW_RESOURCE_ARRAY(methodOop, _old_methods->length());
3006 _matching_new_methods = NEW_RESOURCE_ARRAY(methodOop, _old_methods->length());
3007 _added_methods = NEW_RESOURCE_ARRAY(methodOop, _new_methods->length());
3008 _deleted_methods = NEW_RESOURCE_ARRAY(methodOop, _old_methods->length());
3009
3010 _matching_methods_length = 0;
3011 _deleted_methods_length = 0;
3012 _added_methods_length = 0;
3013
3014 int nj = 0;
3015 int oj = 0;
3016 while (true) {
3017 if (oj >= _old_methods->length()) {
3018 if (nj >= _new_methods->length()) {
3019 break; // we've looked at everything, done
3020 }
3021 // New method at the end
3022 new_method = (methodOop) _new_methods->obj_at(nj);
3023 _added_methods[_added_methods_length++] = new_method;
3024 ++nj;
3025 } else if (nj >= _new_methods->length()) {
3026 // Old method, at the end, is deleted
3027 old_method = (methodOop) _old_methods->obj_at(oj);
3028 _deleted_methods[_deleted_methods_length++] = old_method;
3029 ++oj;
3030 } else {
3031 old_method = (methodOop) _old_methods->obj_at(oj);
3032 new_method = (methodOop) _new_methods->obj_at(nj);
3033 if (old_method->name() == new_method->name()) {
3034 if (old_method->signature() == new_method->signature()) {
3035 _matching_old_methods[_matching_methods_length ] = old_method;
3036 _matching_new_methods[_matching_methods_length++] = new_method;
3037 ++nj;
3038 ++oj;
3039 } else {
3040 // added overloaded have already been moved to the end,
3041 // so this is a deleted overloaded method
3042 _deleted_methods[_deleted_methods_length++] = old_method;
3043 ++oj;
3044 }
3045 } else { // names don't match
3046 if (old_method->name()->fast_compare(new_method->name()) > 0) {
3047 // new method
3048 _added_methods[_added_methods_length++] = new_method;
3049 ++nj;
3050 } else {
3051 // deleted method
3052 _deleted_methods[_deleted_methods_length++] = old_method;
3053 ++oj;
3054 }
3055 }
3056 }
3057 }
3058 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
3059 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
3060 }
3061
3062
3063
3064 // Install the redefinition of a class:
3065 // - house keeping (flushing breakpoints and caches, deoptimizing
3066 // dependent compiled code)
3067 // - replacing parts in the_class with parts from scratch_class
3068 // - adding a weak reference to track the obsolete but interesting
3069 // parts of the_class
3070 // - adjusting constant pool caches and vtables in other classes
3071 // that refer to methods in the_class. These adjustments use the
3072 // SystemDictionary::classes_do() facility which only allows
3073 // a helper method to be specified. The interesting parameters
3074 // that we would like to pass to the helper method are saved in
3075 // static global fields in the VM operation.
3076 void VM_RedefineClasses::redefine_single_class(jclass the_jclass,
3077 instanceKlassHandle scratch_class, TRAPS) {
3078
3079 RC_TIMER_START(_timer_rsc_phase1);
3080
3081 oop the_class_mirror = JNIHandles::resolve_non_null(the_jclass);
3082 klassOop the_class_oop = java_lang_Class::as_klassOop(the_class_mirror);
3083 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
3084
3085 #ifndef JVMTI_KERNEL
3086 // Remove all breakpoints in methods of this class
3087 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
3088 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class_oop);
3089 #endif // !JVMTI_KERNEL
3090
3091 if (the_class_oop == Universe::reflect_invoke_cache()->klass()) {
3092 // We are redefining java.lang.reflect.Method. Method.invoke() is
3093 // cached and users of the cache care about each active version of
3094 // the method so we have to track this previous version.
3095 // Do this before methods get switched
3096 Universe::reflect_invoke_cache()->add_previous_version(
3097 the_class->method_with_idnum(Universe::reflect_invoke_cache()->method_idnum()));
3098 }
3099
3100 // Deoptimize all compiled code that depends on this class
3101 flush_dependent_code(the_class, THREAD);
3102
3103 _old_methods = the_class->methods();
3104 _new_methods = scratch_class->methods();
3105 _the_class_oop = the_class_oop;
3106 compute_added_deleted_matching_methods();
3107 update_jmethod_ids();
3108
3109 // Attach new constant pool to the original klass. The original
3110 // klass still refers to the old constant pool (for now).
3111 scratch_class->constants()->set_pool_holder(the_class());
3112
3113 #if 0
3114 // In theory, with constant pool merging in place we should be able
3115 // to save space by using the new, merged constant pool in place of
3116 // the old constant pool(s). By "pool(s)" I mean the constant pool in
3117 // the klass version we are replacing now and any constant pool(s) in
3118 // previous versions of klass. Nice theory, doesn't work in practice.
3119 // When this code is enabled, even simple programs throw NullPointer
3120 // exceptions. I'm guessing that this is caused by some constant pool
3121 // cache difference between the new, merged constant pool and the
3122 // constant pool that was just being used by the klass. I'm keeping
3123 // this code around to archive the idea, but the code has to remain
3124 // disabled for now.
3125
3126 // Attach each old method to the new constant pool. This can be
3127 // done here since we are past the bytecode verification and
3128 // constant pool optimization phases.
3129 for (int i = _old_methods->length() - 1; i >= 0; i--) {
3130 methodOop method = (methodOop)_old_methods->obj_at(i);
3131 method->set_constants(scratch_class->constants());
3132 }
3133
3134 {
3135 // walk all previous versions of the klass
3136 instanceKlass *ik = (instanceKlass *)the_class()->klass_part();
3137 PreviousVersionWalker pvw(ik);
3138 instanceKlassHandle ikh;
3139 do {
3140 ikh = pvw.next_previous_version();
3141 if (!ikh.is_null()) {
3142 ik = ikh();
3143
3144 // attach previous version of klass to the new constant pool
3145 ik->set_constants(scratch_class->constants());
3146
3147 // Attach each method in the previous version of klass to the
3148 // new constant pool
3149 objArrayOop prev_methods = ik->methods();
3150 for (int i = prev_methods->length() - 1; i >= 0; i--) {
3151 methodOop method = (methodOop)prev_methods->obj_at(i);
3152 method->set_constants(scratch_class->constants());
3153 }
3154 }
3155 } while (!ikh.is_null());
3156 }
3157 #endif
3158
3159 // Replace methods and constantpool
3160 the_class->set_methods(_new_methods);
3161 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods,
3162 // and to be able to undo operation easily.
3163
3164 constantPoolOop old_constants = the_class->constants();
3165 the_class->set_constants(scratch_class->constants());
3166 scratch_class->set_constants(old_constants); // See the previous comment.
3167 #if 0
3168 // We are swapping the guts of "the new class" with the guts of "the
3169 // class". Since the old constant pool has just been attached to "the
3170 // new class", it seems logical to set the pool holder in the old
3171 // constant pool also. However, doing this will change the observable
3172 // class hierarchy for any old methods that are still executing. A
3173 // method can query the identity of its "holder" and this query uses
3174 // the method's constant pool link to find the holder. The change in
3175 // holding class from "the class" to "the new class" can confuse
3176 // things.
3177 //
3178 // Setting the old constant pool's holder will also cause
3179 // verification done during vtable initialization below to fail.
3180 // During vtable initialization, the vtable's class is verified to be
3181 // a subtype of the method's holder. The vtable's class is "the
3182 // class" and the method's holder is gotten from the constant pool
3183 // link in the method itself. For "the class"'s directly implemented
3184 // methods, the method holder is "the class" itself (as gotten from
3185 // the new constant pool). The check works fine in this case. The
3186 // check also works fine for methods inherited from super classes.
3187 //
3188 // Miranda methods are a little more complicated. A miranda method is
3189 // provided by an interface when the class implementing the interface
3190 // does not provide its own method. These interfaces are implemented
3191 // internally as an instanceKlass. These special instanceKlasses
3192 // share the constant pool of the class that "implements" the
3193 // interface. By sharing the constant pool, the method holder of a
3194 // miranda method is the class that "implements" the interface. In a
3195 // non-redefine situation, the subtype check works fine. However, if
3196 // the old constant pool's pool holder is modified, then the check
3197 // fails because there is no class hierarchy relationship between the
3198 // vtable's class and "the new class".
3199
3200 old_constants->set_pool_holder(scratch_class());
3201 #endif
3202
3203 // track which methods are EMCP for add_previous_version() call below
3204 BitMap emcp_methods(_old_methods->length());
3205 int emcp_method_count = 0;
3206 emcp_methods.clear(); // clears 0..(length() - 1)
3207 check_methods_and_mark_as_obsolete(&emcp_methods, &emcp_method_count);
3208 transfer_old_native_function_registrations(the_class);
3209
3210 // The class file bytes from before any retransformable agents mucked
3211 // with them was cached on the scratch class, move to the_class.
3212 // Note: we still want to do this if nothing needed caching since it
3213 // should get cleared in the_class too.
3214 the_class->set_cached_class_file(scratch_class->get_cached_class_file_bytes(),
3215 scratch_class->get_cached_class_file_len());
3216
3217 // Replace inner_classes
3218 typeArrayOop old_inner_classes = the_class->inner_classes();
3219 the_class->set_inner_classes(scratch_class->inner_classes());
3220 scratch_class->set_inner_classes(old_inner_classes);
3221
3222 // Initialize the vtable and interface table after
3223 // methods have been rewritten
3224 {
3225 ResourceMark rm(THREAD);
3226 // no exception should happen here since we explicitly
3227 // do not check loader constraints.
3228 // compare_and_normalize_class_versions has already checked:
3229 // - classloaders unchanged, signatures unchanged
3230 // - all instanceKlasses for redefined classes reused & contents updated
3231 the_class->vtable()->initialize_vtable(false, THREAD);
3232 the_class->itable()->initialize_itable(false, THREAD);
3233 assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())), "redefine exception");
3234 }
3235
3236 // Leave arrays of jmethodIDs and itable index cache unchanged
3237
3238 // Copy the "source file name" attribute from new class version
3239 the_class->set_source_file_name(scratch_class->source_file_name());
3240
3241 // Copy the "source debug extension" attribute from new class version
3242 the_class->set_source_debug_extension(
3243 scratch_class->source_debug_extension());
3244
3245 // Use of javac -g could be different in the old and the new
3246 if (scratch_class->access_flags().has_localvariable_table() !=
3247 the_class->access_flags().has_localvariable_table()) {
3248
3249 AccessFlags flags = the_class->access_flags();
3250 if (scratch_class->access_flags().has_localvariable_table()) {
3251 flags.set_has_localvariable_table();
3252 } else {
3253 flags.clear_has_localvariable_table();
3254 }
3255 the_class->set_access_flags(flags);
3256 }
3257
3258 // Replace class annotation fields values
3259 typeArrayOop old_class_annotations = the_class->class_annotations();
3260 the_class->set_class_annotations(scratch_class->class_annotations());
3261 scratch_class->set_class_annotations(old_class_annotations);
3262
3263 // Replace fields annotation fields values
3264 objArrayOop old_fields_annotations = the_class->fields_annotations();
3265 the_class->set_fields_annotations(scratch_class->fields_annotations());
3266 scratch_class->set_fields_annotations(old_fields_annotations);
3267
3268 // Replace methods annotation fields values
3269 objArrayOop old_methods_annotations = the_class->methods_annotations();
3270 the_class->set_methods_annotations(scratch_class->methods_annotations());
3271 scratch_class->set_methods_annotations(old_methods_annotations);
3272
3273 // Replace methods parameter annotation fields values
3274 objArrayOop old_methods_parameter_annotations =
3275 the_class->methods_parameter_annotations();
3276 the_class->set_methods_parameter_annotations(
3277 scratch_class->methods_parameter_annotations());
3278 scratch_class->set_methods_parameter_annotations(old_methods_parameter_annotations);
3279
3280 // Replace methods default annotation fields values
3281 objArrayOop old_methods_default_annotations =
3282 the_class->methods_default_annotations();
3283 the_class->set_methods_default_annotations(
3284 scratch_class->methods_default_annotations());
3285 scratch_class->set_methods_default_annotations(old_methods_default_annotations);
3286
3287 // Replace minor version number of class file
3288 u2 old_minor_version = the_class->minor_version();
3289 the_class->set_minor_version(scratch_class->minor_version());
3290 scratch_class->set_minor_version(old_minor_version);
3291
3292 // Replace major version number of class file
3293 u2 old_major_version = the_class->major_version();
3294 the_class->set_major_version(scratch_class->major_version());
3295 scratch_class->set_major_version(old_major_version);
3296
3297 // Replace CP indexes for class and name+type of enclosing method
3298 u2 old_class_idx = the_class->enclosing_method_class_index();
3299 u2 old_method_idx = the_class->enclosing_method_method_index();
3300 the_class->set_enclosing_method_indices(
3301 scratch_class->enclosing_method_class_index(),
3302 scratch_class->enclosing_method_method_index());
3303 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx);
3304
3305 // keep track of previous versions of this class
3306 the_class->add_previous_version(scratch_class, &emcp_methods,
3307 emcp_method_count);
3308
3309 RC_TIMER_STOP(_timer_rsc_phase1);
3310 RC_TIMER_START(_timer_rsc_phase2);
3311
3312 // Adjust constantpool caches and vtables for all classes
3313 // that reference methods of the evolved class.
3314 SystemDictionary::classes_do(adjust_cpool_cache_and_vtable, THREAD);
3315
3316 if (the_class->oop_map_cache() != NULL) {
3317 // Flush references to any obsolete methods from the oop map cache
3318 // so that obsolete methods are not pinned.
3319 the_class->oop_map_cache()->flush_obsolete_entries();
3320 }
3321
3322 // increment the classRedefinedCount field in the_class and in any
3323 // direct and indirect subclasses of the_class
3324 increment_class_counter((instanceKlass *)the_class()->klass_part(), THREAD);
3325
3326 // RC_TRACE macro has an embedded ResourceMark
3327 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
3328 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)",
3329 the_class->external_name(),
3330 java_lang_Class::classRedefinedCount(the_class_mirror),
3331 os::available_memory() >> 10));
3332
3333 RC_TIMER_STOP(_timer_rsc_phase2);
3334 } // end redefine_single_class()
3335
3336
3337 // Increment the classRedefinedCount field in the specific instanceKlass
3338 // and in all direct and indirect subclasses.
3339 void VM_RedefineClasses::increment_class_counter(instanceKlass *ik, TRAPS) {
3340 oop class_mirror = ik->java_mirror();
3341 klassOop class_oop = java_lang_Class::as_klassOop(class_mirror);
3342 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
3343 java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
3344
3345 if (class_oop != _the_class_oop) {
3346 // _the_class_oop count is printed at end of redefine_single_class()
3347 RC_TRACE_WITH_THREAD(0x00000008, THREAD,
3348 ("updated count in subclass=%s to %d", ik->external_name(), new_count));
3349 }
3350
3351 for (Klass *subk = ik->subklass(); subk != NULL;
3352 subk = subk->next_sibling()) {
3353 klassOop sub = subk->as_klassOop();
3354 instanceKlass *subik = (instanceKlass *)sub->klass_part();
3355
3356 // recursively do subclasses of the current subclass
3357 increment_class_counter(subik, THREAD);
3358 }
3359 }
3360
3361 #ifndef PRODUCT
3362 void VM_RedefineClasses::check_class(klassOop k_oop,
3363 oop initiating_loader, TRAPS) {
3364 Klass *k = k_oop->klass_part();
3365 if (k->oop_is_instance()) {
3366 HandleMark hm(THREAD);
3367 instanceKlass *ik = (instanceKlass *) k;
3368
3369 if (ik->vtable_length() > 0) {
3370 ResourceMark rm(THREAD);
3371 if (!ik->vtable()->check_no_old_entries()) {
3372 tty->print_cr("klassVtable::check_no_old_entries failure -- OLD method found -- class: %s", ik->signature_name());
3373 ik->vtable()->dump_vtable();
3374 dump_methods();
3375 assert(false, "OLD method found");
3376 }
3377 }
3378 }
3379 }
3380
3381 void VM_RedefineClasses::dump_methods() {
3382 int j;
3383 tty->print_cr("_old_methods --");
3384 for (j = 0; j < _old_methods->length(); ++j) {
3385 methodOop m = (methodOop) _old_methods->obj_at(j);
3386 tty->print("%4d (%5d) ", j, m->vtable_index());
3387 m->access_flags().print_on(tty);
3388 tty->print(" -- ");
3389 m->print_name(tty);
3390 tty->cr();
3391 }
3392 tty->print_cr("_new_methods --");
3393 for (j = 0; j < _new_methods->length(); ++j) {
3394 methodOop m = (methodOop) _new_methods->obj_at(j);
3395 tty->print("%4d (%5d) ", j, m->vtable_index());
3396 m->access_flags().print_on(tty);
3397 tty->print(" -- ");
3398 m->print_name(tty);
3399 tty->cr();
3400 }
3401 tty->print_cr("_matching_(old/new)_methods --");
3402 for (j = 0; j < _matching_methods_length; ++j) {
3403 methodOop m = _matching_old_methods[j];
3404 tty->print("%4d (%5d) ", j, m->vtable_index());
3405 m->access_flags().print_on(tty);
3406 tty->print(" -- ");
3407 m->print_name(tty);
3408 tty->cr();
3409 m = _matching_new_methods[j];
3410 tty->print(" (%5d) ", m->vtable_index());
3411 m->access_flags().print_on(tty);
3412 tty->cr();
3413 }
3414 tty->print_cr("_deleted_methods --");
3415 for (j = 0; j < _deleted_methods_length; ++j) {
3416 methodOop m = _deleted_methods[j];
3417 tty->print("%4d (%5d) ", j, m->vtable_index());
3418 m->access_flags().print_on(tty);
3419 tty->print(" -- ");
3420 m->print_name(tty);
3421 tty->cr();
3422 }
3423 tty->print_cr("_added_methods --");
3424 for (j = 0; j < _added_methods_length; ++j) {
3425 methodOop m = _added_methods[j];
3426 tty->print("%4d (%5d) ", j, m->vtable_index());
3427 m->access_flags().print_on(tty);
3428 tty->print(" -- ");
3429 m->print_name(tty);
3430 tty->cr();
3431 }
3432 }
3433 #endif