1 /*
2 * Copyright (c) 2003, 2013, 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/metadataOnStackMark.hpp"
27 #include "classfile/systemDictionary.hpp"
28 #include "classfile/verifier.hpp"
29 #include "code/codeCache.hpp"
30 #include "compiler/compileBroker.hpp"
31 #include "interpreter/oopMapCache.hpp"
32 #include "interpreter/rewriter.hpp"
33 #include "memory/gcLocker.hpp"
34 #include "memory/metadataFactory.hpp"
35 #include "memory/metaspaceShared.hpp"
36 #include "memory/universe.inline.hpp"
37 #include "oops/fieldStreams.hpp"
38 #include "oops/klassVtable.hpp"
39 #include "prims/jvmtiImpl.hpp"
40 #include "prims/jvmtiRedefineClasses.hpp"
41 #include "prims/methodComparator.hpp"
42 #include "runtime/deoptimization.hpp"
43 #include "runtime/relocator.hpp"
44 #include "utilities/bitMap.inline.hpp"
45
46
47 Array<Method*>* VM_RedefineClasses::_old_methods = NULL;
48 Array<Method*>* VM_RedefineClasses::_new_methods = NULL;
49 Method** VM_RedefineClasses::_matching_old_methods = NULL;
50 Method** VM_RedefineClasses::_matching_new_methods = NULL;
51 Method** VM_RedefineClasses::_deleted_methods = NULL;
52 Method** VM_RedefineClasses::_added_methods = NULL;
53 int VM_RedefineClasses::_matching_methods_length = 0;
54 int VM_RedefineClasses::_deleted_methods_length = 0;
55 int VM_RedefineClasses::_added_methods_length = 0;
56 Klass* VM_RedefineClasses::_the_class_oop = NULL;
57
58
59 VM_RedefineClasses::VM_RedefineClasses(jint class_count,
60 const jvmtiClassDefinition *class_defs,
61 JvmtiClassLoadKind class_load_kind) {
62 _class_count = class_count;
63 _class_defs = class_defs;
64 _class_load_kind = class_load_kind;
65 _res = JVMTI_ERROR_NONE;
66 }
67
68 bool VM_RedefineClasses::doit_prologue() {
69 if (_class_count == 0) {
70 _res = JVMTI_ERROR_NONE;
71 return false;
72 }
73 if (_class_defs == NULL) {
74 _res = JVMTI_ERROR_NULL_POINTER;
75 return false;
76 }
77 for (int i = 0; i < _class_count; i++) {
78 if (_class_defs[i].klass == NULL) {
79 _res = JVMTI_ERROR_INVALID_CLASS;
80 return false;
81 }
82 if (_class_defs[i].class_byte_count == 0) {
83 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT;
84 return false;
85 }
86 if (_class_defs[i].class_bytes == NULL) {
87 _res = JVMTI_ERROR_NULL_POINTER;
88 return false;
89 }
90 }
91
92 // Start timer after all the sanity checks; not quite accurate, but
93 // better than adding a bunch of stop() calls.
94 RC_TIMER_START(_timer_vm_op_prologue);
95
96 // We first load new class versions in the prologue, because somewhere down the
97 // call chain it is required that the current thread is a Java thread.
98 _res = load_new_class_versions(Thread::current());
99 if (_res != JVMTI_ERROR_NONE) {
100 // free any successfully created classes, since none are redefined
101 for (int i = 0; i < _class_count; i++) {
102 if (_scratch_classes[i] != NULL) {
103 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data();
104 // Free the memory for this class at class unloading time. Not before
105 // because CMS might think this is still live.
106 cld->add_to_deallocate_list((InstanceKlass*)_scratch_classes[i]);
107 }
108 }
109 // Free os::malloc allocated memory in load_new_class_version.
110 os::free(_scratch_classes);
111 RC_TIMER_STOP(_timer_vm_op_prologue);
112 return false;
113 }
114
115 RC_TIMER_STOP(_timer_vm_op_prologue);
116 return true;
117 }
118
119 void VM_RedefineClasses::doit() {
120 Thread *thread = Thread::current();
121
122 if (UseSharedSpaces) {
123 // Sharing is enabled so we remap the shared readonly space to
124 // shared readwrite, private just in case we need to redefine
125 // a shared class. We do the remap during the doit() phase of
126 // the safepoint to be safer.
127 if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) {
128 RC_TRACE_WITH_THREAD(0x00000001, thread,
129 ("failed to remap shared readonly space to readwrite, private"));
130 _res = JVMTI_ERROR_INTERNAL;
131 return;
132 }
133 }
134
135 // Mark methods seen on stack and everywhere else so old methods are not
136 // cleaned up if they're on the stack.
137 MetadataOnStackMark md_on_stack;
138 HandleMark hm(thread); // make sure any handles created are deleted
139 // before the stack walk again.
140
141 for (int i = 0; i < _class_count; i++) {
142 redefine_single_class(_class_defs[i].klass, _scratch_classes[i], thread);
143 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data();
144 // Free the memory for this class at class unloading time. Not before
145 // because CMS might think this is still live.
146 cld->add_to_deallocate_list((InstanceKlass*)_scratch_classes[i]);
147 _scratch_classes[i] = NULL;
148 }
149
150 // Disable any dependent concurrent compilations
151 SystemDictionary::notice_modification();
152
153 // Set flag indicating that some invariants are no longer true.
154 // See jvmtiExport.hpp for detailed explanation.
155 JvmtiExport::set_has_redefined_a_class();
156
157 #ifdef ASSERT
158 SystemDictionary::classes_do(check_class, thread);
159 #endif
160 }
161
162 void VM_RedefineClasses::doit_epilogue() {
163 // Free os::malloc allocated memory.
164 os::free(_scratch_classes);
165
166 if (RC_TRACE_ENABLED(0x00000004)) {
167 // Used to have separate timers for "doit" and "all", but the timer
168 // overhead skewed the measurements.
169 jlong doit_time = _timer_rsc_phase1.milliseconds() +
170 _timer_rsc_phase2.milliseconds();
171 jlong all_time = _timer_vm_op_prologue.milliseconds() + doit_time;
172
173 RC_TRACE(0x00000004, ("vm_op: all=" UINT64_FORMAT
174 " prologue=" UINT64_FORMAT " doit=" UINT64_FORMAT, all_time,
175 _timer_vm_op_prologue.milliseconds(), doit_time));
176 RC_TRACE(0x00000004,
177 ("redefine_single_class: phase1=" UINT64_FORMAT " phase2=" UINT64_FORMAT,
178 _timer_rsc_phase1.milliseconds(), _timer_rsc_phase2.milliseconds()));
179 }
180 }
181
182 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) {
183 // classes for primitives cannot be redefined
184 if (java_lang_Class::is_primitive(klass_mirror)) {
185 return false;
186 }
187 Klass* the_class_oop = java_lang_Class::as_Klass(klass_mirror);
188 // classes for arrays cannot be redefined
189 if (the_class_oop == NULL || !the_class_oop->oop_is_instance()) {
190 return false;
191 }
192 return true;
193 }
194
195 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p
196 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For
197 // direct CP entries, there is just the current entry to append. For
198 // indirect and double-indirect CP entries, there are zero or more
199 // referenced CP entries along with the current entry to append.
200 // Indirect and double-indirect CP entries are handled by recursive
201 // calls to append_entry() as needed. The referenced CP entries are
202 // always appended to *merge_cp_p before the referee CP entry. These
203 // referenced CP entries may already exist in *merge_cp_p in which case
204 // there is nothing extra to append and only the current entry is
205 // appended.
206 void VM_RedefineClasses::append_entry(constantPoolHandle scratch_cp,
207 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p,
208 TRAPS) {
209
210 // append is different depending on entry tag type
211 switch (scratch_cp->tag_at(scratch_i).value()) {
212
213 // The old verifier is implemented outside the VM. It loads classes,
214 // but does not resolve constant pool entries directly so we never
215 // see Class entries here with the old verifier. Similarly the old
216 // verifier does not like Class entries in the input constant pool.
217 // The split-verifier is implemented in the VM so it can optionally
218 // and directly resolve constant pool entries to load classes. The
219 // split-verifier can accept either Class entries or UnresolvedClass
220 // entries in the input constant pool. We revert the appended copy
221 // back to UnresolvedClass so that either verifier will be happy
222 // with the constant pool entry.
223 case JVM_CONSTANT_Class:
224 {
225 // revert the copy to JVM_CONSTANT_UnresolvedClass
226 (*merge_cp_p)->unresolved_klass_at_put(*merge_cp_length_p,
227 scratch_cp->klass_name_at(scratch_i));
228
229 if (scratch_i != *merge_cp_length_p) {
230 // The new entry in *merge_cp_p is at a different index than
231 // the new entry in scratch_cp so we need to map the index values.
232 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
233 }
234 (*merge_cp_length_p)++;
235 } break;
236
237 // these are direct CP entries so they can be directly appended,
238 // but double and long take two constant pool entries
239 case JVM_CONSTANT_Double: // fall through
240 case JVM_CONSTANT_Long:
241 {
242 ConstantPool::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) += 2;
251 } break;
252
253 // these are direct CP entries so they can be directly appended
254 case JVM_CONSTANT_Float: // fall through
255 case JVM_CONSTANT_Integer: // fall through
256 case JVM_CONSTANT_Utf8: // fall through
257
258 // This was an indirect CP entry, but it has been changed into
259 // Symbol*s so this entry can be directly appended.
260 case JVM_CONSTANT_String: // fall through
261
262 // These were indirect CP entries, but they have been changed into
263 // Symbol*s so these entries can be directly appended.
264 case JVM_CONSTANT_UnresolvedClass: // fall through
265 {
266 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
267 THREAD);
268
269 if (scratch_i != *merge_cp_length_p) {
270 // The new entry in *merge_cp_p is at a different index than
271 // the new entry in scratch_cp so we need to map the index values.
272 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
273 }
274 (*merge_cp_length_p)++;
275 } break;
276
277 // this is an indirect CP entry so it needs special handling
278 case JVM_CONSTANT_NameAndType:
279 {
280 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i);
281 int new_name_ref_i = 0;
282 bool match = (name_ref_i < *merge_cp_length_p) &&
283 scratch_cp->compare_entry_to(name_ref_i, *merge_cp_p, name_ref_i,
284 THREAD);
285 if (!match) {
286 // forward reference in *merge_cp_p or not a direct match
287
288 int found_i = scratch_cp->find_matching_entry(name_ref_i, *merge_cp_p,
289 THREAD);
290 if (found_i != 0) {
291 guarantee(found_i != name_ref_i,
292 "compare_entry_to() and find_matching_entry() do not agree");
293
294 // Found a matching entry somewhere else in *merge_cp_p so
295 // just need a mapping entry.
296 new_name_ref_i = found_i;
297 map_index(scratch_cp, name_ref_i, found_i);
298 } else {
299 // no match found so we have to append this entry to *merge_cp_p
300 append_entry(scratch_cp, name_ref_i, merge_cp_p, merge_cp_length_p,
301 THREAD);
302 // The above call to append_entry() can only append one entry
303 // so the post call query of *merge_cp_length_p is only for
304 // the sake of consistency.
305 new_name_ref_i = *merge_cp_length_p - 1;
306 }
307 }
308
309 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i);
310 int new_signature_ref_i = 0;
311 match = (signature_ref_i < *merge_cp_length_p) &&
312 scratch_cp->compare_entry_to(signature_ref_i, *merge_cp_p,
313 signature_ref_i, THREAD);
314 if (!match) {
315 // forward reference in *merge_cp_p or not a direct match
316
317 int found_i = scratch_cp->find_matching_entry(signature_ref_i,
318 *merge_cp_p, THREAD);
319 if (found_i != 0) {
320 guarantee(found_i != signature_ref_i,
321 "compare_entry_to() and find_matching_entry() do not agree");
322
323 // Found a matching entry somewhere else in *merge_cp_p so
324 // just need a mapping entry.
325 new_signature_ref_i = found_i;
326 map_index(scratch_cp, signature_ref_i, found_i);
327 } else {
328 // no match found so we have to append this entry to *merge_cp_p
329 append_entry(scratch_cp, signature_ref_i, merge_cp_p,
330 merge_cp_length_p, THREAD);
331 // The above call to append_entry() can only append one entry
332 // so the post call query of *merge_cp_length_p is only for
333 // the sake of consistency.
334 new_signature_ref_i = *merge_cp_length_p - 1;
335 }
336 }
337
338 // If the referenced entries already exist in *merge_cp_p, then
339 // both new_name_ref_i and new_signature_ref_i will both be 0.
340 // In that case, all we are appending is the current entry.
341 if (new_name_ref_i == 0) {
342 new_name_ref_i = name_ref_i;
343 } else {
344 RC_TRACE(0x00080000,
345 ("NameAndType entry@%d name_ref_index change: %d to %d",
346 *merge_cp_length_p, name_ref_i, new_name_ref_i));
347 }
348 if (new_signature_ref_i == 0) {
349 new_signature_ref_i = signature_ref_i;
350 } else {
351 RC_TRACE(0x00080000,
352 ("NameAndType entry@%d signature_ref_index change: %d to %d",
353 *merge_cp_length_p, signature_ref_i, new_signature_ref_i));
354 }
355
356 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p,
357 new_name_ref_i, new_signature_ref_i);
358 if (scratch_i != *merge_cp_length_p) {
359 // The new entry in *merge_cp_p is at a different index than
360 // the new entry in scratch_cp so we need to map the index values.
361 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
362 }
363 (*merge_cp_length_p)++;
364 } break;
365
366 // this is a double-indirect CP entry so it needs special handling
367 case JVM_CONSTANT_Fieldref: // fall through
368 case JVM_CONSTANT_InterfaceMethodref: // fall through
369 case JVM_CONSTANT_Methodref:
370 {
371 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i);
372 int new_klass_ref_i = 0;
373 bool match = (klass_ref_i < *merge_cp_length_p) &&
374 scratch_cp->compare_entry_to(klass_ref_i, *merge_cp_p, klass_ref_i,
375 THREAD);
376 if (!match) {
377 // forward reference in *merge_cp_p or not a direct match
378
379 int found_i = scratch_cp->find_matching_entry(klass_ref_i, *merge_cp_p,
380 THREAD);
381 if (found_i != 0) {
382 guarantee(found_i != klass_ref_i,
383 "compare_entry_to() and find_matching_entry() do not agree");
384
385 // Found a matching entry somewhere else in *merge_cp_p so
386 // just need a mapping entry.
387 new_klass_ref_i = found_i;
388 map_index(scratch_cp, klass_ref_i, found_i);
389 } else {
390 // no match found so we have to append this entry to *merge_cp_p
391 append_entry(scratch_cp, klass_ref_i, merge_cp_p, merge_cp_length_p,
392 THREAD);
393 // The above call to append_entry() can only append one entry
394 // so the post call query of *merge_cp_length_p is only for
395 // the sake of consistency. Without the optimization where we
396 // use JVM_CONSTANT_UnresolvedClass, then up to two entries
397 // could be appended.
398 new_klass_ref_i = *merge_cp_length_p - 1;
399 }
400 }
401
402 int name_and_type_ref_i =
403 scratch_cp->uncached_name_and_type_ref_index_at(scratch_i);
404 int new_name_and_type_ref_i = 0;
405 match = (name_and_type_ref_i < *merge_cp_length_p) &&
406 scratch_cp->compare_entry_to(name_and_type_ref_i, *merge_cp_p,
407 name_and_type_ref_i, THREAD);
408 if (!match) {
409 // forward reference in *merge_cp_p or not a direct match
410
411 int found_i = scratch_cp->find_matching_entry(name_and_type_ref_i,
412 *merge_cp_p, THREAD);
413 if (found_i != 0) {
414 guarantee(found_i != name_and_type_ref_i,
415 "compare_entry_to() and find_matching_entry() do not agree");
416
417 // Found a matching entry somewhere else in *merge_cp_p so
418 // just need a mapping entry.
419 new_name_and_type_ref_i = found_i;
420 map_index(scratch_cp, name_and_type_ref_i, found_i);
421 } else {
422 // no match found so we have to append this entry to *merge_cp_p
423 append_entry(scratch_cp, name_and_type_ref_i, merge_cp_p,
424 merge_cp_length_p, THREAD);
425 // The above call to append_entry() can append more than
426 // one entry so the post call query of *merge_cp_length_p
427 // is required in order to get the right index for the
428 // JVM_CONSTANT_NameAndType entry.
429 new_name_and_type_ref_i = *merge_cp_length_p - 1;
430 }
431 }
432
433 // If the referenced entries already exist in *merge_cp_p, then
434 // both new_klass_ref_i and new_name_and_type_ref_i will both be
435 // 0. In that case, all we are appending is the current entry.
436 if (new_klass_ref_i == 0) {
437 new_klass_ref_i = klass_ref_i;
438 }
439 if (new_name_and_type_ref_i == 0) {
440 new_name_and_type_ref_i = name_and_type_ref_i;
441 }
442
443 const char *entry_name;
444 switch (scratch_cp->tag_at(scratch_i).value()) {
445 case JVM_CONSTANT_Fieldref:
446 entry_name = "Fieldref";
447 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i,
448 new_name_and_type_ref_i);
449 break;
450 case JVM_CONSTANT_InterfaceMethodref:
451 entry_name = "IFMethodref";
452 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p,
453 new_klass_ref_i, new_name_and_type_ref_i);
454 break;
455 case JVM_CONSTANT_Methodref:
456 entry_name = "Methodref";
457 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i,
458 new_name_and_type_ref_i);
459 break;
460 default:
461 guarantee(false, "bad switch");
462 break;
463 }
464
465 if (klass_ref_i != new_klass_ref_i) {
466 RC_TRACE(0x00080000, ("%s entry@%d class_index changed: %d to %d",
467 entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i));
468 }
469 if (name_and_type_ref_i != new_name_and_type_ref_i) {
470 RC_TRACE(0x00080000,
471 ("%s entry@%d name_and_type_index changed: %d to %d",
472 entry_name, *merge_cp_length_p, name_and_type_ref_i,
473 new_name_and_type_ref_i));
474 }
475
476 if (scratch_i != *merge_cp_length_p) {
477 // The new entry in *merge_cp_p is at a different index than
478 // the new entry in scratch_cp so we need to map the index values.
479 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
480 }
481 (*merge_cp_length_p)++;
482 } break;
483
484 // At this stage, Class or UnresolvedClass could be here, but not
485 // ClassIndex
486 case JVM_CONSTANT_ClassIndex: // fall through
487
488 // Invalid is used as the tag for the second constant pool entry
489 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
490 // not be seen by itself.
491 case JVM_CONSTANT_Invalid: // fall through
492
493 // At this stage, String could be here, but not StringIndex
494 case JVM_CONSTANT_StringIndex: // fall through
495
496 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be
497 // here
498 case JVM_CONSTANT_UnresolvedClassInError: // fall through
499
500 default:
501 {
502 // leave a breadcrumb
503 jbyte bad_value = scratch_cp->tag_at(scratch_i).value();
504 ShouldNotReachHere();
505 } break;
506 } // end switch tag value
507 } // end append_entry()
508
509
510 void VM_RedefineClasses::swap_all_method_annotations(int i, int j, instanceKlassHandle scratch_class, TRAPS) {
511 AnnotationArray* save;
512
513 Annotations* sca = scratch_class->annotations();
514 if (sca == NULL) return;
515
516 save = sca->get_method_annotations_of(i);
517 sca->set_method_annotations_of(scratch_class, i, sca->get_method_annotations_of(j), CHECK);
518 sca->set_method_annotations_of(scratch_class, j, save, CHECK);
519
520 save = sca->get_method_parameter_annotations_of(i);
521 sca->set_method_parameter_annotations_of(scratch_class, i, sca->get_method_parameter_annotations_of(j), CHECK);
522 sca->set_method_parameter_annotations_of(scratch_class, j, save, CHECK);
523
524 save = sca->get_method_default_annotations_of(i);
525 sca->set_method_default_annotations_of(scratch_class, i, sca->get_method_default_annotations_of(j), CHECK);
526 sca->set_method_default_annotations_of(scratch_class, j, save, CHECK);
527 }
528
529
530 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions(
531 instanceKlassHandle the_class,
532 instanceKlassHandle scratch_class) {
533 int i;
534
535 // Check superclasses, or rather their names, since superclasses themselves can be
536 // requested to replace.
537 // Check for NULL superclass first since this might be java.lang.Object
538 if (the_class->super() != scratch_class->super() &&
539 (the_class->super() == NULL || scratch_class->super() == NULL ||
540 the_class->super()->name() !=
541 scratch_class->super()->name())) {
542 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
543 }
544
545 // Check if the number, names and order of directly implemented interfaces are the same.
546 // I think in principle we should just check if the sets of names of directly implemented
547 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the
548 // .java file, also changes in .class file) should not matter. However, comparing sets is
549 // technically a bit more difficult, and, more importantly, I am not sure at present that the
550 // order of interfaces does not matter on the implementation level, i.e. that the VM does not
551 // rely on it somewhere.
552 Array<Klass*>* k_interfaces = the_class->local_interfaces();
553 Array<Klass*>* k_new_interfaces = scratch_class->local_interfaces();
554 int n_intfs = k_interfaces->length();
555 if (n_intfs != k_new_interfaces->length()) {
556 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
557 }
558 for (i = 0; i < n_intfs; i++) {
559 if (k_interfaces->at(i)->name() !=
560 k_new_interfaces->at(i)->name()) {
561 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
562 }
563 }
564
565 // Check whether class is in the error init state.
566 if (the_class->is_in_error_state()) {
567 // TBD #5057930: special error code is needed in 1.6
568 return JVMTI_ERROR_INVALID_CLASS;
569 }
570
571 // Check whether class modifiers are the same.
572 jushort old_flags = (jushort) the_class->access_flags().get_flags();
573 jushort new_flags = (jushort) scratch_class->access_flags().get_flags();
574 if (old_flags != new_flags) {
575 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED;
576 }
577
578 // Check if the number, names, types and order of fields declared in these classes
579 // are the same.
580 JavaFieldStream old_fs(the_class);
581 JavaFieldStream new_fs(scratch_class);
582 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) {
583 // access
584 old_flags = old_fs.access_flags().as_short();
585 new_flags = new_fs.access_flags().as_short();
586 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) {
587 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
588 }
589 // offset
590 if (old_fs.offset() != new_fs.offset()) {
591 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
592 }
593 // name and signature
594 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index());
595 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index());
596 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index());
597 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index());
598 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) {
599 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
600 }
601 }
602
603 // If both streams aren't done then we have a differing number of
604 // fields.
605 if (!old_fs.done() || !new_fs.done()) {
606 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
607 }
608
609 // Do a parallel walk through the old and new methods. Detect
610 // cases where they match (exist in both), have been added in
611 // the new methods, or have been deleted (exist only in the
612 // old methods). The class file parser places methods in order
613 // by method name, but does not order overloaded methods by
614 // signature. In order to determine what fate befell the methods,
615 // this code places the overloaded new methods that have matching
616 // old methods in the same order as the old methods and places
617 // new overloaded methods at the end of overloaded methods of
618 // that name. The code for this order normalization is adapted
619 // from the algorithm used in InstanceKlass::find_method().
620 // Since we are swapping out of order entries as we find them,
621 // we only have to search forward through the overloaded methods.
622 // Methods which are added and have the same name as an existing
623 // method (but different signature) will be put at the end of
624 // the methods with that name, and the name mismatch code will
625 // handle them.
626 Array<Method*>* k_old_methods(the_class->methods());
627 Array<Method*>* k_new_methods(scratch_class->methods());
628 int n_old_methods = k_old_methods->length();
629 int n_new_methods = k_new_methods->length();
630 Thread* thread = Thread::current();
631
632 int ni = 0;
633 int oi = 0;
634 while (true) {
635 Method* k_old_method;
636 Method* k_new_method;
637 enum { matched, added, deleted, undetermined } method_was = undetermined;
638
639 if (oi >= n_old_methods) {
640 if (ni >= n_new_methods) {
641 break; // we've looked at everything, done
642 }
643 // New method at the end
644 k_new_method = k_new_methods->at(ni);
645 method_was = added;
646 } else if (ni >= n_new_methods) {
647 // Old method, at the end, is deleted
648 k_old_method = k_old_methods->at(oi);
649 method_was = deleted;
650 } else {
651 // There are more methods in both the old and new lists
652 k_old_method = k_old_methods->at(oi);
653 k_new_method = k_new_methods->at(ni);
654 if (k_old_method->name() != k_new_method->name()) {
655 // Methods are sorted by method name, so a mismatch means added
656 // or deleted
657 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) {
658 method_was = added;
659 } else {
660 method_was = deleted;
661 }
662 } else if (k_old_method->signature() == k_new_method->signature()) {
663 // Both the name and signature match
664 method_was = matched;
665 } else {
666 // The name matches, but the signature doesn't, which means we have to
667 // search forward through the new overloaded methods.
668 int nj; // outside the loop for post-loop check
669 for (nj = ni + 1; nj < n_new_methods; nj++) {
670 Method* m = k_new_methods->at(nj);
671 if (k_old_method->name() != m->name()) {
672 // reached another method name so no more overloaded methods
673 method_was = deleted;
674 break;
675 }
676 if (k_old_method->signature() == m->signature()) {
677 // found a match so swap the methods
678 k_new_methods->at_put(ni, m);
679 k_new_methods->at_put(nj, k_new_method);
680 k_new_method = m;
681 method_was = matched;
682 break;
683 }
684 }
685
686 if (nj >= n_new_methods) {
687 // reached the end without a match; so method was deleted
688 method_was = deleted;
689 }
690 }
691 }
692
693 switch (method_was) {
694 case matched:
695 // methods match, be sure modifiers do too
696 old_flags = (jushort) k_old_method->access_flags().get_flags();
697 new_flags = (jushort) k_new_method->access_flags().get_flags();
698 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) {
699 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED;
700 }
701 {
702 u2 new_num = k_new_method->method_idnum();
703 u2 old_num = k_old_method->method_idnum();
704 if (new_num != old_num) {
705 Method* idnum_owner = scratch_class->method_with_idnum(old_num);
706 if (idnum_owner != NULL) {
707 // There is already a method assigned this idnum -- switch them
708 idnum_owner->set_method_idnum(new_num);
709 }
710 k_new_method->set_method_idnum(old_num);
711 swap_all_method_annotations(old_num, new_num, scratch_class, thread);
712 if (thread->has_pending_exception()) {
713 return JVMTI_ERROR_OUT_OF_MEMORY;
714 }
715 }
716 }
717 RC_TRACE(0x00008000, ("Method matched: new: %s [%d] == old: %s [%d]",
718 k_new_method->name_and_sig_as_C_string(), ni,
719 k_old_method->name_and_sig_as_C_string(), oi));
720 // advance to next pair of methods
721 ++oi;
722 ++ni;
723 break;
724 case added:
725 // method added, see if it is OK
726 new_flags = (jushort) k_new_method->access_flags().get_flags();
727 if ((new_flags & JVM_ACC_PRIVATE) == 0
728 // hack: private should be treated as final, but alas
729 || (new_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
730 ) {
731 // new methods must be private
732 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
733 }
734 {
735 u2 num = the_class->next_method_idnum();
736 if (num == ConstMethod::UNSET_IDNUM) {
737 // cannot add any more methods
738 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
739 }
740 u2 new_num = k_new_method->method_idnum();
741 Method* idnum_owner = scratch_class->method_with_idnum(num);
742 if (idnum_owner != NULL) {
743 // There is already a method assigned this idnum -- switch them
744 idnum_owner->set_method_idnum(new_num);
745 }
746 k_new_method->set_method_idnum(num);
747 swap_all_method_annotations(new_num, num, scratch_class, thread);
748 if (thread->has_pending_exception()) {
749 return JVMTI_ERROR_OUT_OF_MEMORY;
750 }
751 }
752 RC_TRACE(0x00008000, ("Method added: new: %s [%d]",
753 k_new_method->name_and_sig_as_C_string(), ni));
754 ++ni; // advance to next new method
755 break;
756 case deleted:
757 // method deleted, see if it is OK
758 old_flags = (jushort) k_old_method->access_flags().get_flags();
759 if ((old_flags & JVM_ACC_PRIVATE) == 0
760 // hack: private should be treated as final, but alas
761 || (old_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
762 ) {
763 // deleted methods must be private
764 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED;
765 }
766 RC_TRACE(0x00008000, ("Method deleted: old: %s [%d]",
767 k_old_method->name_and_sig_as_C_string(), oi));
768 ++oi; // advance to next old method
769 break;
770 default:
771 ShouldNotReachHere();
772 }
773 }
774
775 return JVMTI_ERROR_NONE;
776 }
777
778
779 // Find new constant pool index value for old constant pool index value
780 // by seaching the index map. Returns zero (0) if there is no mapped
781 // value for the old constant pool index.
782 int VM_RedefineClasses::find_new_index(int old_index) {
783 if (_index_map_count == 0) {
784 // map is empty so nothing can be found
785 return 0;
786 }
787
788 if (old_index < 1 || old_index >= _index_map_p->length()) {
789 // The old_index is out of range so it is not mapped. This should
790 // not happen in regular constant pool merging use, but it can
791 // happen if a corrupt annotation is processed.
792 return 0;
793 }
794
795 int value = _index_map_p->at(old_index);
796 if (value == -1) {
797 // the old_index is not mapped
798 return 0;
799 }
800
801 return value;
802 } // end find_new_index()
803
804
805 // Returns true if the current mismatch is due to a resolved/unresolved
806 // class pair. Otherwise, returns false.
807 bool VM_RedefineClasses::is_unresolved_class_mismatch(constantPoolHandle cp1,
808 int index1, constantPoolHandle cp2, int index2) {
809
810 jbyte t1 = cp1->tag_at(index1).value();
811 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) {
812 return false; // wrong entry type; not our special case
813 }
814
815 jbyte t2 = cp2->tag_at(index2).value();
816 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) {
817 return false; // wrong entry type; not our special case
818 }
819
820 if (t1 == t2) {
821 return false; // not a mismatch; not our special case
822 }
823
824 char *s1 = cp1->klass_name_at(index1)->as_C_string();
825 char *s2 = cp2->klass_name_at(index2)->as_C_string();
826 if (strcmp(s1, s2) != 0) {
827 return false; // strings don't match; not our special case
828 }
829
830 return true; // made it through the gauntlet; this is our special case
831 } // end is_unresolved_class_mismatch()
832
833
834 jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) {
835
836 // For consistency allocate memory using os::malloc wrapper.
837 _scratch_classes = (Klass**)
838 os::malloc(sizeof(Klass*) * _class_count, mtClass);
839 if (_scratch_classes == NULL) {
840 return JVMTI_ERROR_OUT_OF_MEMORY;
841 }
842 // Zero initialize the _scratch_classes array.
843 for (int i = 0; i < _class_count; i++) {
844 _scratch_classes[i] = NULL;
845 }
846
847 ResourceMark rm(THREAD);
848
849 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
850 // state can only be NULL if the current thread is exiting which
851 // should not happen since we're trying to do a RedefineClasses
852 guarantee(state != NULL, "exiting thread calling load_new_class_versions");
853 for (int i = 0; i < _class_count; i++) {
854 // Create HandleMark so that any handles created while loading new class
855 // versions are deleted. Constant pools are deallocated while merging
856 // constant pools
857 HandleMark hm(THREAD);
858
859 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass);
860 // classes for primitives cannot be redefined
861 if (!is_modifiable_class(mirror)) {
862 return JVMTI_ERROR_UNMODIFIABLE_CLASS;
863 }
864 Klass* the_class_oop = java_lang_Class::as_Klass(mirror);
865 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
866 Symbol* the_class_sym = the_class->name();
867
868 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
869 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
870 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)",
871 the_class->external_name(), _class_load_kind,
872 os::available_memory() >> 10));
873
874 ClassFileStream st((u1*) _class_defs[i].class_bytes,
875 _class_defs[i].class_byte_count, (char *)"__VM_RedefineClasses__");
876
877 // Parse the stream.
878 Handle the_class_loader(THREAD, the_class->class_loader());
879 Handle protection_domain(THREAD, the_class->protection_domain());
880 // Set redefined class handle in JvmtiThreadState class.
881 // This redefined class is sent to agent event handler for class file
882 // load hook event.
883 state->set_class_being_redefined(&the_class, _class_load_kind);
884
885 Klass* k = SystemDictionary::parse_stream(the_class_sym,
886 the_class_loader,
887 protection_domain,
888 &st,
889 THREAD);
890 // Clear class_being_redefined just to be sure.
891 state->clear_class_being_redefined();
892
893 // TODO: if this is retransform, and nothing changed we can skip it
894
895 instanceKlassHandle scratch_class (THREAD, k);
896
897 // Need to clean up allocated InstanceKlass if there's an error so assign
898 // the result here. Caller deallocates all the scratch classes in case of
899 // an error.
900 _scratch_classes[i] = k;
901
902 if (HAS_PENDING_EXCEPTION) {
903 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
904 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
905 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("parse_stream exception: '%s'",
906 ex_name->as_C_string()));
907 CLEAR_PENDING_EXCEPTION;
908
909 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) {
910 return JVMTI_ERROR_UNSUPPORTED_VERSION;
911 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) {
912 return JVMTI_ERROR_INVALID_CLASS_FORMAT;
913 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) {
914 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION;
915 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
916 // The message will be "XXX (wrong name: YYY)"
917 return JVMTI_ERROR_NAMES_DONT_MATCH;
918 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
919 return JVMTI_ERROR_OUT_OF_MEMORY;
920 } else { // Just in case more exceptions can be thrown..
921 return JVMTI_ERROR_FAILS_VERIFICATION;
922 }
923 }
924
925 // Ensure class is linked before redefine
926 if (!the_class->is_linked()) {
927 the_class->link_class(THREAD);
928 if (HAS_PENDING_EXCEPTION) {
929 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
930 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
931 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("link_class exception: '%s'",
932 ex_name->as_C_string()));
933 CLEAR_PENDING_EXCEPTION;
934 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
935 return JVMTI_ERROR_OUT_OF_MEMORY;
936 } else {
937 return JVMTI_ERROR_INTERNAL;
938 }
939 }
940 }
941
942 // Do the validity checks in compare_and_normalize_class_versions()
943 // before verifying the byte codes. By doing these checks first, we
944 // limit the number of functions that require redirection from
945 // the_class to scratch_class. In particular, we don't have to
946 // modify JNI GetSuperclass() and thus won't change its performance.
947 jvmtiError res = compare_and_normalize_class_versions(the_class,
948 scratch_class);
949 if (res != JVMTI_ERROR_NONE) {
950 return res;
951 }
952
953 // verify what the caller passed us
954 {
955 // The bug 6214132 caused the verification to fail.
956 // Information about the_class and scratch_class is temporarily
957 // recorded into jvmtiThreadState. This data is used to redirect
958 // the_class to scratch_class in the JVM_* functions called by the
959 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed
960 // description.
961 RedefineVerifyMark rvm(&the_class, &scratch_class, state);
962 Verifier::verify(
963 scratch_class, Verifier::ThrowException, true, THREAD);
964 }
965
966 if (HAS_PENDING_EXCEPTION) {
967 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
968 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
969 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
970 ("verify_byte_codes exception: '%s'", ex_name->as_C_string()));
971 CLEAR_PENDING_EXCEPTION;
972 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
973 return JVMTI_ERROR_OUT_OF_MEMORY;
974 } else {
975 // tell the caller the bytecodes are bad
976 return JVMTI_ERROR_FAILS_VERIFICATION;
977 }
978 }
979
980 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD);
981 if (res != JVMTI_ERROR_NONE) {
982 return res;
983 }
984
985 if (VerifyMergedCPBytecodes) {
986 // verify what we have done during constant pool merging
987 {
988 RedefineVerifyMark rvm(&the_class, &scratch_class, state);
989 Verifier::verify(scratch_class, Verifier::ThrowException, true, THREAD);
990 }
991
992 if (HAS_PENDING_EXCEPTION) {
993 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
994 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
995 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
996 ("verify_byte_codes post merge-CP exception: '%s'",
997 ex_name->as_C_string()));
998 CLEAR_PENDING_EXCEPTION;
999 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1000 return JVMTI_ERROR_OUT_OF_MEMORY;
1001 } else {
1002 // tell the caller that constant pool merging screwed up
1003 return JVMTI_ERROR_INTERNAL;
1004 }
1005 }
1006 }
1007
1008 Rewriter::rewrite(scratch_class, THREAD);
1009 if (!HAS_PENDING_EXCEPTION) {
1010 scratch_class->link_methods(THREAD);
1011 }
1012 if (HAS_PENDING_EXCEPTION) {
1013 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1014 CLEAR_PENDING_EXCEPTION;
1015 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1016 return JVMTI_ERROR_OUT_OF_MEMORY;
1017 } else {
1018 return JVMTI_ERROR_INTERNAL;
1019 }
1020 }
1021
1022 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1023 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
1024 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)",
1025 the_class->external_name(), os::available_memory() >> 10));
1026 }
1027
1028 return JVMTI_ERROR_NONE;
1029 }
1030
1031
1032 // Map old_index to new_index as needed. scratch_cp is only needed
1033 // for RC_TRACE() calls.
1034 void VM_RedefineClasses::map_index(constantPoolHandle scratch_cp,
1035 int old_index, int new_index) {
1036 if (find_new_index(old_index) != 0) {
1037 // old_index is already mapped
1038 return;
1039 }
1040
1041 if (old_index == new_index) {
1042 // no mapping is needed
1043 return;
1044 }
1045
1046 _index_map_p->at_put(old_index, new_index);
1047 _index_map_count++;
1048
1049 RC_TRACE(0x00040000, ("mapped tag %d at index %d to %d",
1050 scratch_cp->tag_at(old_index).value(), old_index, new_index));
1051 } // end map_index()
1052
1053
1054 // Merge old_cp and scratch_cp and return the results of the merge via
1055 // merge_cp_p. The number of entries in *merge_cp_p is returned via
1056 // merge_cp_length_p. The entries in old_cp occupy the same locations
1057 // in *merge_cp_p. Also creates a map of indices from entries in
1058 // scratch_cp to the corresponding entry in *merge_cp_p. Index map
1059 // entries are only created for entries in scratch_cp that occupy a
1060 // different location in *merged_cp_p.
1061 bool VM_RedefineClasses::merge_constant_pools(constantPoolHandle old_cp,
1062 constantPoolHandle scratch_cp, constantPoolHandle *merge_cp_p,
1063 int *merge_cp_length_p, TRAPS) {
1064
1065 if (merge_cp_p == NULL) {
1066 assert(false, "caller must provide scratch constantPool");
1067 return false; // robustness
1068 }
1069 if (merge_cp_length_p == NULL) {
1070 assert(false, "caller must provide scratch CP length");
1071 return false; // robustness
1072 }
1073 // Worst case we need old_cp->length() + scratch_cp()->length(),
1074 // but the caller might be smart so make sure we have at least
1075 // the minimum.
1076 if ((*merge_cp_p)->length() < old_cp->length()) {
1077 assert(false, "merge area too small");
1078 return false; // robustness
1079 }
1080
1081 RC_TRACE_WITH_THREAD(0x00010000, THREAD,
1082 ("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(),
1083 scratch_cp->length()));
1084
1085 {
1086 // Pass 0:
1087 // The old_cp is copied to *merge_cp_p; this means that any code
1088 // using old_cp does not have to change. This work looks like a
1089 // perfect fit for ConstantPool*::copy_cp_to(), but we need to
1090 // handle one special case:
1091 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass
1092 // This will make verification happy.
1093
1094 int old_i; // index into old_cp
1095
1096 // index zero (0) is not used in constantPools
1097 for (old_i = 1; old_i < old_cp->length(); old_i++) {
1098 // leave debugging crumb
1099 jbyte old_tag = old_cp->tag_at(old_i).value();
1100 switch (old_tag) {
1101 case JVM_CONSTANT_Class:
1102 case JVM_CONSTANT_UnresolvedClass:
1103 // revert the copy to JVM_CONSTANT_UnresolvedClass
1104 // May be resolving while calling this so do the same for
1105 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition)
1106 (*merge_cp_p)->unresolved_klass_at_put(old_i,
1107 old_cp->klass_name_at(old_i));
1108 break;
1109
1110 case JVM_CONSTANT_Double:
1111 case JVM_CONSTANT_Long:
1112 // just copy the entry to *merge_cp_p, but double and long take
1113 // two constant pool entries
1114 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1115 old_i++;
1116 break;
1117
1118 default:
1119 // just copy the entry to *merge_cp_p
1120 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1121 break;
1122 }
1123 } // end for each old_cp entry
1124
1125 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_0);
1126
1127 // We don't need to sanity check that *merge_cp_length_p is within
1128 // *merge_cp_p bounds since we have the minimum on-entry check above.
1129 (*merge_cp_length_p) = old_i;
1130 }
1131
1132 // merge_cp_len should be the same as old_cp->length() at this point
1133 // so this trace message is really a "warm-and-breathing" message.
1134 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1135 ("after pass 0: merge_cp_len=%d", *merge_cp_length_p));
1136
1137 int scratch_i; // index into scratch_cp
1138 {
1139 // Pass 1a:
1140 // Compare scratch_cp entries to the old_cp entries that we have
1141 // already copied to *merge_cp_p. In this pass, we are eliminating
1142 // exact duplicates (matching entry at same index) so we only
1143 // compare entries in the common indice range.
1144 int increment = 1;
1145 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length());
1146 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) {
1147 switch (scratch_cp->tag_at(scratch_i).value()) {
1148 case JVM_CONSTANT_Double:
1149 case JVM_CONSTANT_Long:
1150 // double and long take two constant pool entries
1151 increment = 2;
1152 break;
1153
1154 default:
1155 increment = 1;
1156 break;
1157 }
1158
1159 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p,
1160 scratch_i, CHECK_0);
1161 if (match) {
1162 // found a match at the same index so nothing more to do
1163 continue;
1164 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i,
1165 *merge_cp_p, scratch_i)) {
1166 // The mismatch in compare_entry_to() above is because of a
1167 // resolved versus unresolved class entry at the same index
1168 // with the same string value. Since Pass 0 reverted any
1169 // class entries to unresolved class entries in *merge_cp_p,
1170 // we go with the unresolved class entry.
1171 continue;
1172 }
1173
1174 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p,
1175 CHECK_0);
1176 if (found_i != 0) {
1177 guarantee(found_i != scratch_i,
1178 "compare_entry_to() and find_matching_entry() do not agree");
1179
1180 // Found a matching entry somewhere else in *merge_cp_p so
1181 // just need a mapping entry.
1182 map_index(scratch_cp, scratch_i, found_i);
1183 continue;
1184 }
1185
1186 // The find_matching_entry() call above could fail to find a match
1187 // due to a resolved versus unresolved class or string entry situation
1188 // like we solved above with the is_unresolved_*_mismatch() calls.
1189 // However, we would have to call is_unresolved_*_mismatch() over
1190 // all of *merge_cp_p (potentially) and that doesn't seem to be
1191 // worth the time.
1192
1193 // No match found so we have to append this entry and any unique
1194 // referenced entries to *merge_cp_p.
1195 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1196 CHECK_0);
1197 }
1198 }
1199
1200 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1201 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1202 *merge_cp_length_p, scratch_i, _index_map_count));
1203
1204 if (scratch_i < scratch_cp->length()) {
1205 // Pass 1b:
1206 // old_cp is smaller than scratch_cp so there are entries in
1207 // scratch_cp that we have not yet processed. We take care of
1208 // those now.
1209 int increment = 1;
1210 for (; scratch_i < scratch_cp->length(); scratch_i += increment) {
1211 switch (scratch_cp->tag_at(scratch_i).value()) {
1212 case JVM_CONSTANT_Double:
1213 case JVM_CONSTANT_Long:
1214 // double and long take two constant pool entries
1215 increment = 2;
1216 break;
1217
1218 default:
1219 increment = 1;
1220 break;
1221 }
1222
1223 int found_i =
1224 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0);
1225 if (found_i != 0) {
1226 // Found a matching entry somewhere else in *merge_cp_p so
1227 // just need a mapping entry.
1228 map_index(scratch_cp, scratch_i, found_i);
1229 continue;
1230 }
1231
1232 // No match found so we have to append this entry and any unique
1233 // referenced entries to *merge_cp_p.
1234 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1235 CHECK_0);
1236 }
1237
1238 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1239 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1240 *merge_cp_length_p, scratch_i, _index_map_count));
1241 }
1242
1243 return true;
1244 } // end merge_constant_pools()
1245
1246
1247 // Scoped object to clean up the constant pool(s) created for merging
1248 class MergeCPCleaner {
1249 ClassLoaderData* _loader_data;
1250 ConstantPool* _cp;
1251 ConstantPool* _scratch_cp;
1252 public:
1253 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) :
1254 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {}
1255 ~MergeCPCleaner() {
1256 _loader_data->add_to_deallocate_list(_cp);
1257 if (_scratch_cp != NULL) {
1258 _loader_data->add_to_deallocate_list(_scratch_cp);
1259 }
1260 }
1261 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; }
1262 };
1263
1264 // Merge constant pools between the_class and scratch_class and
1265 // potentially rewrite bytecodes in scratch_class to use the merged
1266 // constant pool.
1267 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite(
1268 instanceKlassHandle the_class, instanceKlassHandle scratch_class,
1269 TRAPS) {
1270 // worst case merged constant pool length is old and new combined
1271 int merge_cp_length = the_class->constants()->length()
1272 + scratch_class->constants()->length();
1273
1274 // Constant pools are not easily reused so we allocate a new one
1275 // each time.
1276 // merge_cp is created unsafe for concurrent GC processing. It
1277 // should be marked safe before discarding it. Even though
1278 // garbage, if it crosses a card boundary, it may be scanned
1279 // in order to find the start of the first complete object on the card.
1280 ClassLoaderData* loader_data = the_class->class_loader_data();
1281 ConstantPool* merge_cp_oop =
1282 ConstantPool::allocate(loader_data,
1283 merge_cp_length,
1284 THREAD);
1285 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop);
1286
1287 HandleMark hm(THREAD); // make sure handles are cleared before
1288 // MergeCPCleaner clears out merge_cp_oop
1289 constantPoolHandle merge_cp(THREAD, merge_cp_oop);
1290
1291 // Get constants() from the old class because it could have been rewritten
1292 // while we were at a safepoint allocating a new constant pool.
1293 constantPoolHandle old_cp(THREAD, the_class->constants());
1294 constantPoolHandle scratch_cp(THREAD, scratch_class->constants());
1295
1296 // If the length changed, the class was redefined out from under us. Return
1297 // an error.
1298 if (merge_cp_length != the_class->constants()->length()
1299 + scratch_class->constants()->length()) {
1300 return JVMTI_ERROR_INTERNAL;
1301 }
1302
1303 // Update the version number of the constant pool
1304 merge_cp->increment_and_save_version(old_cp->version());
1305
1306 ResourceMark rm(THREAD);
1307 _index_map_count = 0;
1308 _index_map_p = new intArray(scratch_cp->length(), -1);
1309
1310 // reference to the cp holder is needed for copy_operands()
1311 merge_cp->set_pool_holder(scratch_class());
1312 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp,
1313 &merge_cp_length, THREAD);
1314 merge_cp->set_pool_holder(NULL);
1315
1316 if (!result) {
1317 // The merge can fail due to memory allocation failure or due
1318 // to robustness checks.
1319 return JVMTI_ERROR_INTERNAL;
1320 }
1321
1322 RC_TRACE_WITH_THREAD(0x00010000, THREAD,
1323 ("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count));
1324
1325 if (_index_map_count == 0) {
1326 // there is nothing to map between the new and merged constant pools
1327
1328 if (old_cp->length() == scratch_cp->length()) {
1329 // The old and new constant pools are the same length and the
1330 // index map is empty. This means that the three constant pools
1331 // are equivalent (but not the same). Unfortunately, the new
1332 // constant pool has not gone through link resolution nor have
1333 // the new class bytecodes gone through constant pool cache
1334 // rewriting so we can't use the old constant pool with the new
1335 // class.
1336
1337 // toss the merged constant pool at return
1338 } else if (old_cp->length() < scratch_cp->length()) {
1339 // The old constant pool has fewer entries than the new constant
1340 // pool and the index map is empty. This means the new constant
1341 // pool is a superset of the old constant pool. However, the old
1342 // class bytecodes have already gone through constant pool cache
1343 // rewriting so we can't use the new constant pool with the old
1344 // class.
1345
1346 // toss the merged constant pool at return
1347 } else {
1348 // The old constant pool has more entries than the new constant
1349 // pool and the index map is empty. This means that both the old
1350 // and merged constant pools are supersets of the new constant
1351 // pool.
1352
1353 // Replace the new constant pool with a shrunken copy of the
1354 // merged constant pool
1355 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, THREAD);
1356 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1357 // It can't be cleaned up while there are handles to it.
1358 cp_cleaner.add_scratch_cp(scratch_cp());
1359 }
1360 } else {
1361 if (RC_TRACE_ENABLED(0x00040000)) {
1362 // don't want to loop unless we are tracing
1363 int count = 0;
1364 for (int i = 1; i < _index_map_p->length(); i++) {
1365 int value = _index_map_p->at(i);
1366
1367 if (value != -1) {
1368 RC_TRACE_WITH_THREAD(0x00040000, THREAD,
1369 ("index_map[%d]: old=%d new=%d", count, i, value));
1370 count++;
1371 }
1372 }
1373 }
1374
1375 // We have entries mapped between the new and merged constant pools
1376 // so we have to rewrite some constant pool references.
1377 if (!rewrite_cp_refs(scratch_class, THREAD)) {
1378 return JVMTI_ERROR_INTERNAL;
1379 }
1380
1381 // Replace the new constant pool with a shrunken copy of the
1382 // merged constant pool so now the rewritten bytecodes have
1383 // valid references; the previous new constant pool will get
1384 // GCed.
1385 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, THREAD);
1386 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1387 // It can't be cleaned up while there are handles to it.
1388 cp_cleaner.add_scratch_cp(scratch_cp());
1389 }
1390
1391 return JVMTI_ERROR_NONE;
1392 } // end merge_cp_and_rewrite()
1393
1394
1395 // Rewrite constant pool references in klass scratch_class.
1396 bool VM_RedefineClasses::rewrite_cp_refs(instanceKlassHandle scratch_class,
1397 TRAPS) {
1398
1399 // rewrite constant pool references in the methods:
1400 if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) {
1401 // propagate failure back to caller
1402 return false;
1403 }
1404
1405 // rewrite constant pool references in the class_annotations:
1406 if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) {
1407 // propagate failure back to caller
1408 return false;
1409 }
1410
1411 // rewrite constant pool references in the fields_annotations:
1412 if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) {
1413 // propagate failure back to caller
1414 return false;
1415 }
1416
1417 // rewrite constant pool references in the methods_annotations:
1418 if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) {
1419 // propagate failure back to caller
1420 return false;
1421 }
1422
1423 // rewrite constant pool references in the methods_parameter_annotations:
1424 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class,
1425 THREAD)) {
1426 // propagate failure back to caller
1427 return false;
1428 }
1429
1430 // rewrite constant pool references in the methods_default_annotations:
1431 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class,
1432 THREAD)) {
1433 // propagate failure back to caller
1434 return false;
1435 }
1436
1437 return true;
1438 } // end rewrite_cp_refs()
1439
1440
1441 // Rewrite constant pool references in the methods.
1442 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(
1443 instanceKlassHandle scratch_class, TRAPS) {
1444
1445 Array<Method*>* methods = scratch_class->methods();
1446
1447 if (methods == NULL || methods->length() == 0) {
1448 // no methods so nothing to do
1449 return true;
1450 }
1451
1452 // rewrite constant pool references in the methods:
1453 for (int i = methods->length() - 1; i >= 0; i--) {
1454 methodHandle method(THREAD, methods->at(i));
1455 methodHandle new_method;
1456 rewrite_cp_refs_in_method(method, &new_method, CHECK_false);
1457 if (!new_method.is_null()) {
1458 // the method has been replaced so save the new method version
1459 methods->at_put(i, new_method());
1460 }
1461 }
1462
1463 return true;
1464 }
1465
1466
1467 // Rewrite constant pool references in the specific method. This code
1468 // was adapted from Rewriter::rewrite_method().
1469 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method,
1470 methodHandle *new_method_p, TRAPS) {
1471
1472 *new_method_p = methodHandle(); // default is no new method
1473
1474 // We cache a pointer to the bytecodes here in code_base. If GC
1475 // moves the Method*, then the bytecodes will also move which
1476 // will likely cause a crash. We create a No_Safepoint_Verifier
1477 // object to detect whether we pass a possible safepoint in this
1478 // code block.
1479 No_Safepoint_Verifier nsv;
1480
1481 // Bytecodes and their length
1482 address code_base = method->code_base();
1483 int code_length = method->code_size();
1484
1485 int bc_length;
1486 for (int bci = 0; bci < code_length; bci += bc_length) {
1487 address bcp = code_base + bci;
1488 Bytecodes::Code c = (Bytecodes::Code)(*bcp);
1489
1490 bc_length = Bytecodes::length_for(c);
1491 if (bc_length == 0) {
1492 // More complicated bytecodes report a length of zero so
1493 // we have to try again a slightly different way.
1494 bc_length = Bytecodes::length_at(method(), bcp);
1495 }
1496
1497 assert(bc_length != 0, "impossible bytecode length");
1498
1499 switch (c) {
1500 case Bytecodes::_ldc:
1501 {
1502 int cp_index = *(bcp + 1);
1503 int new_index = find_new_index(cp_index);
1504
1505 if (StressLdcRewrite && new_index == 0) {
1506 // If we are stressing ldc -> ldc_w rewriting, then we
1507 // always need a new_index value.
1508 new_index = cp_index;
1509 }
1510 if (new_index != 0) {
1511 // the original index is mapped so we have more work to do
1512 if (!StressLdcRewrite && new_index <= max_jubyte) {
1513 // The new value can still use ldc instead of ldc_w
1514 // unless we are trying to stress ldc -> ldc_w rewriting
1515 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1516 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
1517 bcp, cp_index, new_index));
1518 *(bcp + 1) = new_index;
1519 } else {
1520 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1521 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d",
1522 Bytecodes::name(c), bcp, cp_index, new_index));
1523 // the new value needs ldc_w instead of ldc
1524 u_char inst_buffer[4]; // max instruction size is 4 bytes
1525 bcp = (address)inst_buffer;
1526 // construct new instruction sequence
1527 *bcp = Bytecodes::_ldc_w;
1528 bcp++;
1529 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w.
1530 // See comment below for difference between put_Java_u2()
1531 // and put_native_u2().
1532 Bytes::put_Java_u2(bcp, new_index);
1533
1534 Relocator rc(method, NULL /* no RelocatorListener needed */);
1535 methodHandle m;
1536 {
1537 Pause_No_Safepoint_Verifier pnsv(&nsv);
1538
1539 // ldc is 2 bytes and ldc_w is 3 bytes
1540 m = rc.insert_space_at(bci, 3, inst_buffer, THREAD);
1541 if (m.is_null() || HAS_PENDING_EXCEPTION) {
1542 guarantee(false, "insert_space_at() failed");
1543 }
1544 }
1545
1546 // return the new method so that the caller can update
1547 // the containing class
1548 *new_method_p = method = m;
1549 // switch our bytecode processing loop from the old method
1550 // to the new method
1551 code_base = method->code_base();
1552 code_length = method->code_size();
1553 bcp = code_base + bci;
1554 c = (Bytecodes::Code)(*bcp);
1555 bc_length = Bytecodes::length_for(c);
1556 assert(bc_length != 0, "sanity check");
1557 } // end we need ldc_w instead of ldc
1558 } // end if there is a mapped index
1559 } break;
1560
1561 // these bytecodes have a two-byte constant pool index
1562 case Bytecodes::_anewarray : // fall through
1563 case Bytecodes::_checkcast : // fall through
1564 case Bytecodes::_getfield : // fall through
1565 case Bytecodes::_getstatic : // fall through
1566 case Bytecodes::_instanceof : // fall through
1567 case Bytecodes::_invokeinterface: // fall through
1568 case Bytecodes::_invokespecial : // fall through
1569 case Bytecodes::_invokestatic : // fall through
1570 case Bytecodes::_invokevirtual : // fall through
1571 case Bytecodes::_ldc_w : // fall through
1572 case Bytecodes::_ldc2_w : // fall through
1573 case Bytecodes::_multianewarray : // fall through
1574 case Bytecodes::_new : // fall through
1575 case Bytecodes::_putfield : // fall through
1576 case Bytecodes::_putstatic :
1577 {
1578 address p = bcp + 1;
1579 int cp_index = Bytes::get_Java_u2(p);
1580 int new_index = find_new_index(cp_index);
1581 if (new_index != 0) {
1582 // the original index is mapped so update w/ new value
1583 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1584 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
1585 bcp, cp_index, new_index));
1586 // Rewriter::rewrite_method() uses put_native_u2() in this
1587 // situation because it is reusing the constant pool index
1588 // location for a native index into the constantPoolCache.
1589 // Since we are updating the constant pool index prior to
1590 // verification and constantPoolCache initialization, we
1591 // need to keep the new index in Java byte order.
1592 Bytes::put_Java_u2(p, new_index);
1593 }
1594 } break;
1595 }
1596 } // end for each bytecode
1597 } // end rewrite_cp_refs_in_method()
1598
1599
1600 // Rewrite constant pool references in the class_annotations field.
1601 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(
1602 instanceKlassHandle scratch_class, TRAPS) {
1603
1604 AnnotationArray* class_annotations = scratch_class->class_annotations();
1605 if (class_annotations == NULL || class_annotations->length() == 0) {
1606 // no class_annotations so nothing to do
1607 return true;
1608 }
1609
1610 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1611 ("class_annotations length=%d", class_annotations->length()));
1612
1613 int byte_i = 0; // byte index into class_annotations
1614 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i,
1615 THREAD);
1616 }
1617
1618
1619 // Rewrite constant pool references in an annotations typeArray. This
1620 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute
1621 // that is described in section 4.8.15 of the 2nd-edition of the VM spec:
1622 //
1623 // annotations_typeArray {
1624 // u2 num_annotations;
1625 // annotation annotations[num_annotations];
1626 // }
1627 //
1628 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray(
1629 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1630
1631 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1632 // not enough room for num_annotations field
1633 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1634 ("length() is too small for num_annotations field"));
1635 return false;
1636 }
1637
1638 u2 num_annotations = Bytes::get_Java_u2((address)
1639 annotations_typeArray->adr_at(byte_i_ref));
1640 byte_i_ref += 2;
1641
1642 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1643 ("num_annotations=%d", num_annotations));
1644
1645 int calc_num_annotations = 0;
1646 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
1647 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
1648 byte_i_ref, THREAD)) {
1649 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1650 ("bad annotation_struct at %d", calc_num_annotations));
1651 // propagate failure back to caller
1652 return false;
1653 }
1654 }
1655 assert(num_annotations == calc_num_annotations, "sanity check");
1656
1657 return true;
1658 } // end rewrite_cp_refs_in_annotations_typeArray()
1659
1660
1661 // Rewrite constant pool references in the annotation struct portion of
1662 // an annotations_typeArray. This "structure" is from section 4.8.15 of
1663 // the 2nd-edition of the VM spec:
1664 //
1665 // struct annotation {
1666 // u2 type_index;
1667 // u2 num_element_value_pairs;
1668 // {
1669 // u2 element_name_index;
1670 // element_value value;
1671 // } element_value_pairs[num_element_value_pairs];
1672 // }
1673 //
1674 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct(
1675 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1676 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) {
1677 // not enough room for smallest annotation_struct
1678 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1679 ("length() is too small for annotation_struct"));
1680 return false;
1681 }
1682
1683 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray,
1684 byte_i_ref, "mapped old type_index=%d", THREAD);
1685
1686 u2 num_element_value_pairs = Bytes::get_Java_u2((address)
1687 annotations_typeArray->adr_at(byte_i_ref));
1688 byte_i_ref += 2;
1689
1690 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1691 ("type_index=%d num_element_value_pairs=%d", type_index,
1692 num_element_value_pairs));
1693
1694 int calc_num_element_value_pairs = 0;
1695 for (; calc_num_element_value_pairs < num_element_value_pairs;
1696 calc_num_element_value_pairs++) {
1697 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1698 // not enough room for another element_name_index, let alone
1699 // the rest of another component
1700 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1701 ("length() is too small for element_name_index"));
1702 return false;
1703 }
1704
1705 u2 element_name_index = rewrite_cp_ref_in_annotation_data(
1706 annotations_typeArray, byte_i_ref,
1707 "mapped old element_name_index=%d", THREAD);
1708
1709 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1710 ("element_name_index=%d", element_name_index));
1711
1712 if (!rewrite_cp_refs_in_element_value(annotations_typeArray,
1713 byte_i_ref, THREAD)) {
1714 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1715 ("bad element_value at %d", calc_num_element_value_pairs));
1716 // propagate failure back to caller
1717 return false;
1718 }
1719 } // end for each component
1720 assert(num_element_value_pairs == calc_num_element_value_pairs,
1721 "sanity check");
1722
1723 return true;
1724 } // end rewrite_cp_refs_in_annotation_struct()
1725
1726
1727 // Rewrite a constant pool reference at the current position in
1728 // annotations_typeArray if needed. Returns the original constant
1729 // pool reference if a rewrite was not needed or the new constant
1730 // pool reference if a rewrite was needed.
1731 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data(
1732 AnnotationArray* annotations_typeArray, int &byte_i_ref,
1733 const char * trace_mesg, TRAPS) {
1734
1735 address cp_index_addr = (address)
1736 annotations_typeArray->adr_at(byte_i_ref);
1737 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr);
1738 u2 new_cp_index = find_new_index(old_cp_index);
1739 if (new_cp_index != 0) {
1740 RC_TRACE_WITH_THREAD(0x02000000, THREAD, (trace_mesg, old_cp_index));
1741 Bytes::put_Java_u2(cp_index_addr, new_cp_index);
1742 old_cp_index = new_cp_index;
1743 }
1744 byte_i_ref += 2;
1745 return old_cp_index;
1746 }
1747
1748
1749 // Rewrite constant pool references in the element_value portion of an
1750 // annotations_typeArray. This "structure" is from section 4.8.15.1 of
1751 // the 2nd-edition of the VM spec:
1752 //
1753 // struct element_value {
1754 // u1 tag;
1755 // union {
1756 // u2 const_value_index;
1757 // {
1758 // u2 type_name_index;
1759 // u2 const_name_index;
1760 // } enum_const_value;
1761 // u2 class_info_index;
1762 // annotation annotation_value;
1763 // struct {
1764 // u2 num_values;
1765 // element_value values[num_values];
1766 // } array_value;
1767 // } value;
1768 // }
1769 //
1770 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value(
1771 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1772
1773 if ((byte_i_ref + 1) > annotations_typeArray->length()) {
1774 // not enough room for a tag let alone the rest of an element_value
1775 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1776 ("length() is too small for a tag"));
1777 return false;
1778 }
1779
1780 u1 tag = annotations_typeArray->at(byte_i_ref);
1781 byte_i_ref++;
1782 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("tag='%c'", tag));
1783
1784 switch (tag) {
1785 // These BaseType tag values are from Table 4.2 in VM spec:
1786 case 'B': // byte
1787 case 'C': // char
1788 case 'D': // double
1789 case 'F': // float
1790 case 'I': // int
1791 case 'J': // long
1792 case 'S': // short
1793 case 'Z': // boolean
1794
1795 // The remaining tag values are from Table 4.8 in the 2nd-edition of
1796 // the VM spec:
1797 case 's':
1798 {
1799 // For the above tag values (including the BaseType values),
1800 // value.const_value_index is right union field.
1801
1802 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1803 // not enough room for a const_value_index
1804 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1805 ("length() is too small for a const_value_index"));
1806 return false;
1807 }
1808
1809 u2 const_value_index = rewrite_cp_ref_in_annotation_data(
1810 annotations_typeArray, byte_i_ref,
1811 "mapped old const_value_index=%d", THREAD);
1812
1813 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1814 ("const_value_index=%d", const_value_index));
1815 } break;
1816
1817 case 'e':
1818 {
1819 // for the above tag value, value.enum_const_value is right union field
1820
1821 if ((byte_i_ref + 4) > annotations_typeArray->length()) {
1822 // not enough room for a enum_const_value
1823 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1824 ("length() is too small for a enum_const_value"));
1825 return false;
1826 }
1827
1828 u2 type_name_index = rewrite_cp_ref_in_annotation_data(
1829 annotations_typeArray, byte_i_ref,
1830 "mapped old type_name_index=%d", THREAD);
1831
1832 u2 const_name_index = rewrite_cp_ref_in_annotation_data(
1833 annotations_typeArray, byte_i_ref,
1834 "mapped old const_name_index=%d", THREAD);
1835
1836 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1837 ("type_name_index=%d const_name_index=%d", type_name_index,
1838 const_name_index));
1839 } break;
1840
1841 case 'c':
1842 {
1843 // for the above tag value, value.class_info_index is right union field
1844
1845 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1846 // not enough room for a class_info_index
1847 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1848 ("length() is too small for a class_info_index"));
1849 return false;
1850 }
1851
1852 u2 class_info_index = rewrite_cp_ref_in_annotation_data(
1853 annotations_typeArray, byte_i_ref,
1854 "mapped old class_info_index=%d", THREAD);
1855
1856 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1857 ("class_info_index=%d", class_info_index));
1858 } break;
1859
1860 case '@':
1861 // For the above tag value, value.attr_value is the right union
1862 // field. This is a nested annotation.
1863 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
1864 byte_i_ref, THREAD)) {
1865 // propagate failure back to caller
1866 return false;
1867 }
1868 break;
1869
1870 case '[':
1871 {
1872 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1873 // not enough room for a num_values field
1874 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1875 ("length() is too small for a num_values field"));
1876 return false;
1877 }
1878
1879 // For the above tag value, value.array_value is the right union
1880 // field. This is an array of nested element_value.
1881 u2 num_values = Bytes::get_Java_u2((address)
1882 annotations_typeArray->adr_at(byte_i_ref));
1883 byte_i_ref += 2;
1884 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("num_values=%d", num_values));
1885
1886 int calc_num_values = 0;
1887 for (; calc_num_values < num_values; calc_num_values++) {
1888 if (!rewrite_cp_refs_in_element_value(
1889 annotations_typeArray, byte_i_ref, THREAD)) {
1890 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1891 ("bad nested element_value at %d", calc_num_values));
1892 // propagate failure back to caller
1893 return false;
1894 }
1895 }
1896 assert(num_values == calc_num_values, "sanity check");
1897 } break;
1898
1899 default:
1900 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("bad tag=0x%x", tag));
1901 return false;
1902 } // end decode tag field
1903
1904 return true;
1905 } // end rewrite_cp_refs_in_element_value()
1906
1907
1908 // Rewrite constant pool references in a fields_annotations field.
1909 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations(
1910 instanceKlassHandle scratch_class, TRAPS) {
1911
1912 Annotations* sca = scratch_class->annotations();
1913 if (sca == NULL) return true;
1914
1915 Array<AnnotationArray*>* fields_annotations = sca->fields_annotations();
1916
1917 if (fields_annotations == NULL || fields_annotations->length() == 0) {
1918 // no fields_annotations so nothing to do
1919 return true;
1920 }
1921
1922 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1923 ("fields_annotations length=%d", fields_annotations->length()));
1924
1925 for (int i = 0; i < fields_annotations->length(); i++) {
1926 AnnotationArray* field_annotations = fields_annotations->at(i);
1927 if (field_annotations == NULL || field_annotations->length() == 0) {
1928 // this field does not have any annotations so skip it
1929 continue;
1930 }
1931
1932 int byte_i = 0; // byte index into field_annotations
1933 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i,
1934 THREAD)) {
1935 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1936 ("bad field_annotations at %d", i));
1937 // propagate failure back to caller
1938 return false;
1939 }
1940 }
1941
1942 return true;
1943 } // end rewrite_cp_refs_in_fields_annotations()
1944
1945
1946 // Rewrite constant pool references in a methods_annotations field.
1947 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations(
1948 instanceKlassHandle scratch_class, TRAPS) {
1949
1950 Annotations* sca = scratch_class->annotations();
1951 if (sca == NULL) return true;
1952
1953 Array<AnnotationArray*>* methods_annotations = sca->methods_annotations();
1954
1955 if (methods_annotations == NULL || methods_annotations->length() == 0) {
1956 // no methods_annotations so nothing to do
1957 return true;
1958 }
1959
1960 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1961 ("methods_annotations length=%d", methods_annotations->length()));
1962
1963 for (int i = 0; i < methods_annotations->length(); i++) {
1964 AnnotationArray* method_annotations = methods_annotations->at(i);
1965 if (method_annotations == NULL || method_annotations->length() == 0) {
1966 // this method does not have any annotations so skip it
1967 continue;
1968 }
1969
1970 int byte_i = 0; // byte index into method_annotations
1971 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i,
1972 THREAD)) {
1973 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1974 ("bad method_annotations at %d", i));
1975 // propagate failure back to caller
1976 return false;
1977 }
1978 }
1979
1980 return true;
1981 } // end rewrite_cp_refs_in_methods_annotations()
1982
1983
1984 // Rewrite constant pool references in a methods_parameter_annotations
1985 // field. This "structure" is adapted from the
1986 // RuntimeVisibleParameterAnnotations_attribute described in section
1987 // 4.8.17 of the 2nd-edition of the VM spec:
1988 //
1989 // methods_parameter_annotations_typeArray {
1990 // u1 num_parameters;
1991 // {
1992 // u2 num_annotations;
1993 // annotation annotations[num_annotations];
1994 // } parameter_annotations[num_parameters];
1995 // }
1996 //
1997 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations(
1998 instanceKlassHandle scratch_class, TRAPS) {
1999
2000 Annotations* sca = scratch_class->annotations();
2001 if (sca == NULL) return true;
2002
2003 Array<AnnotationArray*>* methods_parameter_annotations =
2004 sca->methods_parameter_annotations();
2005
2006 if (methods_parameter_annotations == NULL
2007 || methods_parameter_annotations->length() == 0) {
2008 // no methods_parameter_annotations so nothing to do
2009 return true;
2010 }
2011
2012 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2013 ("methods_parameter_annotations length=%d",
2014 methods_parameter_annotations->length()));
2015
2016 for (int i = 0; i < methods_parameter_annotations->length(); i++) {
2017 AnnotationArray* method_parameter_annotations = methods_parameter_annotations->at(i);
2018 if (method_parameter_annotations == NULL
2019 || method_parameter_annotations->length() == 0) {
2020 // this method does not have any parameter annotations so skip it
2021 continue;
2022 }
2023
2024 if (method_parameter_annotations->length() < 1) {
2025 // not enough room for a num_parameters field
2026 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2027 ("length() is too small for a num_parameters field at %d", i));
2028 return false;
2029 }
2030
2031 int byte_i = 0; // byte index into method_parameter_annotations
2032
2033 u1 num_parameters = method_parameter_annotations->at(byte_i);
2034 byte_i++;
2035
2036 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2037 ("num_parameters=%d", num_parameters));
2038
2039 int calc_num_parameters = 0;
2040 for (; calc_num_parameters < num_parameters; calc_num_parameters++) {
2041 if (!rewrite_cp_refs_in_annotations_typeArray(
2042 method_parameter_annotations, byte_i, THREAD)) {
2043 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2044 ("bad method_parameter_annotations at %d", calc_num_parameters));
2045 // propagate failure back to caller
2046 return false;
2047 }
2048 }
2049 assert(num_parameters == calc_num_parameters, "sanity check");
2050 }
2051
2052 return true;
2053 } // end rewrite_cp_refs_in_methods_parameter_annotations()
2054
2055
2056 // Rewrite constant pool references in a methods_default_annotations
2057 // field. This "structure" is adapted from the AnnotationDefault_attribute
2058 // that is described in section 4.8.19 of the 2nd-edition of the VM spec:
2059 //
2060 // methods_default_annotations_typeArray {
2061 // element_value default_value;
2062 // }
2063 //
2064 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations(
2065 instanceKlassHandle scratch_class, TRAPS) {
2066
2067 Annotations* sca = scratch_class->annotations();
2068 if (sca == NULL) return true;
2069
2070 Array<AnnotationArray*>* methods_default_annotations =
2071 sca->methods_default_annotations();
2072
2073 if (methods_default_annotations == NULL
2074 || methods_default_annotations->length() == 0) {
2075 // no methods_default_annotations so nothing to do
2076 return true;
2077 }
2078
2079 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2080 ("methods_default_annotations length=%d",
2081 methods_default_annotations->length()));
2082
2083 for (int i = 0; i < methods_default_annotations->length(); i++) {
2084 AnnotationArray* method_default_annotations = methods_default_annotations->at(i);
2085 if (method_default_annotations == NULL
2086 || method_default_annotations->length() == 0) {
2087 // this method does not have any default annotations so skip it
2088 continue;
2089 }
2090
2091 int byte_i = 0; // byte index into method_default_annotations
2092
2093 if (!rewrite_cp_refs_in_element_value(
2094 method_default_annotations, byte_i, THREAD)) {
2095 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2096 ("bad default element_value at %d", i));
2097 // propagate failure back to caller
2098 return false;
2099 }
2100 }
2101
2102 return true;
2103 } // end rewrite_cp_refs_in_methods_default_annotations()
2104
2105
2106 // Rewrite constant pool references in the method's stackmap table.
2107 // These "structures" are adapted from the StackMapTable_attribute that
2108 // is described in section 4.8.4 of the 6.0 version of the VM spec
2109 // (dated 2005.10.26):
2110 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2111 //
2112 // stack_map {
2113 // u2 number_of_entries;
2114 // stack_map_frame entries[number_of_entries];
2115 // }
2116 //
2117 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table(
2118 methodHandle method, TRAPS) {
2119
2120 if (!method->has_stackmap_table()) {
2121 return;
2122 }
2123
2124 AnnotationArray* stackmap_data = method->stackmap_data();
2125 address stackmap_p = (address)stackmap_data->adr_at(0);
2126 address stackmap_end = stackmap_p + stackmap_data->length();
2127
2128 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries");
2129 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p);
2130 stackmap_p += 2;
2131
2132 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2133 ("number_of_entries=%u", number_of_entries));
2134
2135 // walk through each stack_map_frame
2136 u2 calc_number_of_entries = 0;
2137 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) {
2138 // The stack_map_frame structure is a u1 frame_type followed by
2139 // 0 or more bytes of data:
2140 //
2141 // union stack_map_frame {
2142 // same_frame;
2143 // same_locals_1_stack_item_frame;
2144 // same_locals_1_stack_item_frame_extended;
2145 // chop_frame;
2146 // same_frame_extended;
2147 // append_frame;
2148 // full_frame;
2149 // }
2150
2151 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type");
2152 // The Linux compiler does not like frame_type to be u1 or u2. It
2153 // issues the following warning for the first if-statement below:
2154 //
2155 // "warning: comparison is always true due to limited range of data type"
2156 //
2157 u4 frame_type = *stackmap_p;
2158 stackmap_p++;
2159
2160 // same_frame {
2161 // u1 frame_type = SAME; /* 0-63 */
2162 // }
2163 if (frame_type >= 0 && frame_type <= 63) {
2164 // nothing more to do for same_frame
2165 }
2166
2167 // same_locals_1_stack_item_frame {
2168 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */
2169 // verification_type_info stack[1];
2170 // }
2171 else if (frame_type >= 64 && frame_type <= 127) {
2172 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2173 calc_number_of_entries, frame_type, THREAD);
2174 }
2175
2176 // reserved for future use
2177 else if (frame_type >= 128 && frame_type <= 246) {
2178 // nothing more to do for reserved frame_types
2179 }
2180
2181 // same_locals_1_stack_item_frame_extended {
2182 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */
2183 // u2 offset_delta;
2184 // verification_type_info stack[1];
2185 // }
2186 else if (frame_type == 247) {
2187 stackmap_p += 2;
2188 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2189 calc_number_of_entries, frame_type, THREAD);
2190 }
2191
2192 // chop_frame {
2193 // u1 frame_type = CHOP; /* 248-250 */
2194 // u2 offset_delta;
2195 // }
2196 else if (frame_type >= 248 && frame_type <= 250) {
2197 stackmap_p += 2;
2198 }
2199
2200 // same_frame_extended {
2201 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/
2202 // u2 offset_delta;
2203 // }
2204 else if (frame_type == 251) {
2205 stackmap_p += 2;
2206 }
2207
2208 // append_frame {
2209 // u1 frame_type = APPEND; /* 252-254 */
2210 // u2 offset_delta;
2211 // verification_type_info locals[frame_type - 251];
2212 // }
2213 else if (frame_type >= 252 && frame_type <= 254) {
2214 assert(stackmap_p + 2 <= stackmap_end,
2215 "no room for offset_delta");
2216 stackmap_p += 2;
2217 u1 len = frame_type - 251;
2218 for (u1 i = 0; i < len; i++) {
2219 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2220 calc_number_of_entries, frame_type, THREAD);
2221 }
2222 }
2223
2224 // full_frame {
2225 // u1 frame_type = FULL_FRAME; /* 255 */
2226 // u2 offset_delta;
2227 // u2 number_of_locals;
2228 // verification_type_info locals[number_of_locals];
2229 // u2 number_of_stack_items;
2230 // verification_type_info stack[number_of_stack_items];
2231 // }
2232 else if (frame_type == 255) {
2233 assert(stackmap_p + 2 + 2 <= stackmap_end,
2234 "no room for smallest full_frame");
2235 stackmap_p += 2;
2236
2237 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p);
2238 stackmap_p += 2;
2239
2240 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) {
2241 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2242 calc_number_of_entries, frame_type, THREAD);
2243 }
2244
2245 // Use the largest size for the number_of_stack_items, but only get
2246 // the right number of bytes.
2247 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p);
2248 stackmap_p += 2;
2249
2250 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) {
2251 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2252 calc_number_of_entries, frame_type, THREAD);
2253 }
2254 }
2255 } // end while there is a stack_map_frame
2256 assert(number_of_entries == calc_number_of_entries, "sanity check");
2257 } // end rewrite_cp_refs_in_stack_map_table()
2258
2259
2260 // Rewrite constant pool references in the verification type info
2261 // portion of the method's stackmap table. These "structures" are
2262 // adapted from the StackMapTable_attribute that is described in
2263 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26):
2264 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2265 //
2266 // The verification_type_info structure is a u1 tag followed by 0 or
2267 // more bytes of data:
2268 //
2269 // union verification_type_info {
2270 // Top_variable_info;
2271 // Integer_variable_info;
2272 // Float_variable_info;
2273 // Long_variable_info;
2274 // Double_variable_info;
2275 // Null_variable_info;
2276 // UninitializedThis_variable_info;
2277 // Object_variable_info;
2278 // Uninitialized_variable_info;
2279 // }
2280 //
2281 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info(
2282 address& stackmap_p_ref, address stackmap_end, u2 frame_i,
2283 u1 frame_type, TRAPS) {
2284
2285 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag");
2286 u1 tag = *stackmap_p_ref;
2287 stackmap_p_ref++;
2288
2289 switch (tag) {
2290 // Top_variable_info {
2291 // u1 tag = ITEM_Top; /* 0 */
2292 // }
2293 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top
2294 case 0: // fall through
2295
2296 // Integer_variable_info {
2297 // u1 tag = ITEM_Integer; /* 1 */
2298 // }
2299 case ITEM_Integer: // fall through
2300
2301 // Float_variable_info {
2302 // u1 tag = ITEM_Float; /* 2 */
2303 // }
2304 case ITEM_Float: // fall through
2305
2306 // Double_variable_info {
2307 // u1 tag = ITEM_Double; /* 3 */
2308 // }
2309 case ITEM_Double: // fall through
2310
2311 // Long_variable_info {
2312 // u1 tag = ITEM_Long; /* 4 */
2313 // }
2314 case ITEM_Long: // fall through
2315
2316 // Null_variable_info {
2317 // u1 tag = ITEM_Null; /* 5 */
2318 // }
2319 case ITEM_Null: // fall through
2320
2321 // UninitializedThis_variable_info {
2322 // u1 tag = ITEM_UninitializedThis; /* 6 */
2323 // }
2324 case ITEM_UninitializedThis:
2325 // nothing more to do for the above tag types
2326 break;
2327
2328 // Object_variable_info {
2329 // u1 tag = ITEM_Object; /* 7 */
2330 // u2 cpool_index;
2331 // }
2332 case ITEM_Object:
2333 {
2334 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index");
2335 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref);
2336 u2 new_cp_index = find_new_index(cpool_index);
2337 if (new_cp_index != 0) {
2338 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2339 ("mapped old cpool_index=%d", cpool_index));
2340 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
2341 cpool_index = new_cp_index;
2342 }
2343 stackmap_p_ref += 2;
2344
2345 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2346 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i,
2347 frame_type, cpool_index));
2348 } break;
2349
2350 // Uninitialized_variable_info {
2351 // u1 tag = ITEM_Uninitialized; /* 8 */
2352 // u2 offset;
2353 // }
2354 case ITEM_Uninitialized:
2355 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset");
2356 stackmap_p_ref += 2;
2357 break;
2358
2359 default:
2360 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2361 ("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag));
2362 ShouldNotReachHere();
2363 break;
2364 } // end switch (tag)
2365 } // end rewrite_cp_refs_in_verification_type_info()
2366
2367
2368 // Change the constant pool associated with klass scratch_class to
2369 // scratch_cp. If shrink is true, then scratch_cp_length elements
2370 // are copied from scratch_cp to a smaller constant pool and the
2371 // smaller constant pool is associated with scratch_class.
2372 void VM_RedefineClasses::set_new_constant_pool(
2373 ClassLoaderData* loader_data,
2374 instanceKlassHandle scratch_class, constantPoolHandle scratch_cp,
2375 int scratch_cp_length, TRAPS) {
2376 assert(scratch_cp->length() >= scratch_cp_length, "sanity check");
2377
2378 // scratch_cp is a merged constant pool and has enough space for a
2379 // worst case merge situation. We want to associate the minimum
2380 // sized constant pool with the klass to save space.
2381 constantPoolHandle smaller_cp(THREAD,
2382 ConstantPool::allocate(loader_data, scratch_cp_length, THREAD));
2383
2384 // preserve version() value in the smaller copy
2385 int version = scratch_cp->version();
2386 assert(version != 0, "sanity check");
2387 smaller_cp->set_version(version);
2388
2389 // attach klass to new constant pool
2390 // reference to the cp holder is needed for copy_operands()
2391 smaller_cp->set_pool_holder(scratch_class());
2392
2393 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
2394 scratch_cp = smaller_cp;
2395
2396 // attach new constant pool to klass
2397 scratch_class->set_constants(scratch_cp());
2398
2399 int i; // for portability
2400
2401 // update each field in klass to use new constant pool indices as needed
2402 for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) {
2403 jshort cur_index = fs.name_index();
2404 jshort new_index = find_new_index(cur_index);
2405 if (new_index != 0) {
2406 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2407 ("field-name_index change: %d to %d", cur_index, new_index));
2408 fs.set_name_index(new_index);
2409 }
2410 cur_index = fs.signature_index();
2411 new_index = find_new_index(cur_index);
2412 if (new_index != 0) {
2413 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2414 ("field-signature_index change: %d to %d", cur_index, new_index));
2415 fs.set_signature_index(new_index);
2416 }
2417 cur_index = fs.initval_index();
2418 new_index = find_new_index(cur_index);
2419 if (new_index != 0) {
2420 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2421 ("field-initval_index change: %d to %d", cur_index, new_index));
2422 fs.set_initval_index(new_index);
2423 }
2424 cur_index = fs.generic_signature_index();
2425 new_index = find_new_index(cur_index);
2426 if (new_index != 0) {
2427 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2428 ("field-generic_signature change: %d to %d", cur_index, new_index));
2429 fs.set_generic_signature_index(new_index);
2430 }
2431 } // end for each field
2432
2433 // Update constant pool indices in the inner classes info to use
2434 // new constant indices as needed. The inner classes info is a
2435 // quadruple:
2436 // (inner_class_info, outer_class_info, inner_name, inner_access_flags)
2437 InnerClassesIterator iter(scratch_class);
2438 for (; !iter.done(); iter.next()) {
2439 int cur_index = iter.inner_class_info_index();
2440 if (cur_index == 0) {
2441 continue; // JVM spec. allows null inner class refs so skip it
2442 }
2443 int new_index = find_new_index(cur_index);
2444 if (new_index != 0) {
2445 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2446 ("inner_class_info change: %d to %d", cur_index, new_index));
2447 iter.set_inner_class_info_index(new_index);
2448 }
2449 cur_index = iter.outer_class_info_index();
2450 new_index = find_new_index(cur_index);
2451 if (new_index != 0) {
2452 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2453 ("outer_class_info change: %d to %d", cur_index, new_index));
2454 iter.set_outer_class_info_index(new_index);
2455 }
2456 cur_index = iter.inner_name_index();
2457 new_index = find_new_index(cur_index);
2458 if (new_index != 0) {
2459 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2460 ("inner_name change: %d to %d", cur_index, new_index));
2461 iter.set_inner_name_index(new_index);
2462 }
2463 } // end for each inner class
2464
2465 // Attach each method in klass to the new constant pool and update
2466 // to use new constant pool indices as needed:
2467 Array<Method*>* methods = scratch_class->methods();
2468 for (i = methods->length() - 1; i >= 0; i--) {
2469 methodHandle method(THREAD, methods->at(i));
2470 method->set_constants(scratch_cp());
2471
2472 int new_index = find_new_index(method->name_index());
2473 if (new_index != 0) {
2474 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2475 ("method-name_index change: %d to %d", method->name_index(),
2476 new_index));
2477 method->set_name_index(new_index);
2478 }
2479 new_index = find_new_index(method->signature_index());
2480 if (new_index != 0) {
2481 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2482 ("method-signature_index change: %d to %d",
2483 method->signature_index(), new_index));
2484 method->set_signature_index(new_index);
2485 }
2486 new_index = find_new_index(method->generic_signature_index());
2487 if (new_index != 0) {
2488 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2489 ("method-generic_signature_index change: %d to %d",
2490 method->generic_signature_index(), new_index));
2491 method->set_generic_signature_index(new_index);
2492 }
2493
2494 // Update constant pool indices in the method's checked exception
2495 // table to use new constant indices as needed.
2496 int cext_length = method->checked_exceptions_length();
2497 if (cext_length > 0) {
2498 CheckedExceptionElement * cext_table =
2499 method->checked_exceptions_start();
2500 for (int j = 0; j < cext_length; j++) {
2501 int cur_index = cext_table[j].class_cp_index;
2502 int new_index = find_new_index(cur_index);
2503 if (new_index != 0) {
2504 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2505 ("cext-class_cp_index change: %d to %d", cur_index, new_index));
2506 cext_table[j].class_cp_index = (u2)new_index;
2507 }
2508 } // end for each checked exception table entry
2509 } // end if there are checked exception table entries
2510
2511 // Update each catch type index in the method's exception table
2512 // to use new constant pool indices as needed. The exception table
2513 // holds quadruple entries of the form:
2514 // (beg_bci, end_bci, handler_bci, klass_index)
2515
2516 ExceptionTable ex_table(method());
2517 int ext_length = ex_table.length();
2518
2519 for (int j = 0; j < ext_length; j ++) {
2520 int cur_index = ex_table.catch_type_index(j);
2521 int new_index = find_new_index(cur_index);
2522 if (new_index != 0) {
2523 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2524 ("ext-klass_index change: %d to %d", cur_index, new_index));
2525 ex_table.set_catch_type_index(j, new_index);
2526 }
2527 } // end for each exception table entry
2528
2529 // Update constant pool indices in the method's local variable
2530 // table to use new constant indices as needed. The local variable
2531 // table hold sextuple entries of the form:
2532 // (start_pc, length, name_index, descriptor_index, signature_index, slot)
2533 int lvt_length = method->localvariable_table_length();
2534 if (lvt_length > 0) {
2535 LocalVariableTableElement * lv_table =
2536 method->localvariable_table_start();
2537 for (int j = 0; j < lvt_length; j++) {
2538 int cur_index = lv_table[j].name_cp_index;
2539 int new_index = find_new_index(cur_index);
2540 if (new_index != 0) {
2541 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2542 ("lvt-name_cp_index change: %d to %d", cur_index, new_index));
2543 lv_table[j].name_cp_index = (u2)new_index;
2544 }
2545 cur_index = lv_table[j].descriptor_cp_index;
2546 new_index = find_new_index(cur_index);
2547 if (new_index != 0) {
2548 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2549 ("lvt-descriptor_cp_index change: %d to %d", cur_index,
2550 new_index));
2551 lv_table[j].descriptor_cp_index = (u2)new_index;
2552 }
2553 cur_index = lv_table[j].signature_cp_index;
2554 new_index = find_new_index(cur_index);
2555 if (new_index != 0) {
2556 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2557 ("lvt-signature_cp_index change: %d to %d", cur_index, new_index));
2558 lv_table[j].signature_cp_index = (u2)new_index;
2559 }
2560 } // end for each local variable table entry
2561 } // end if there are local variable table entries
2562
2563 rewrite_cp_refs_in_stack_map_table(method, THREAD);
2564 } // end for each method
2565 } // end set_new_constant_pool()
2566
2567
2568 void VM_RedefineClasses::adjust_array_vtable(Klass* k_oop) {
2569 ArrayKlass* ak = ArrayKlass::cast(k_oop);
2570 bool trace_name_printed = false;
2571 ak->vtable()->adjust_method_entries(_matching_old_methods,
2572 _matching_new_methods,
2573 _matching_methods_length,
2574 &trace_name_printed);
2575 }
2576
2577 // Unevolving classes may point to methods of the_class directly
2578 // from their constant pool caches, itables, and/or vtables. We
2579 // use the SystemDictionary::classes_do() facility and this helper
2580 // to fix up these pointers.
2581 //
2582 // Note: We currently don't support updating the vtable in
2583 // arrayKlassOops. See Open Issues in jvmtiRedefineClasses.hpp.
2584 void VM_RedefineClasses::adjust_cpool_cache_and_vtable(Klass* k_oop,
2585 ClassLoaderData* initiating_loader,
2586 TRAPS) {
2587 Klass *k = k_oop;
2588 if (k->oop_is_instance()) {
2589 HandleMark hm(THREAD);
2590 InstanceKlass *ik = (InstanceKlass *) k;
2591
2592 // HotSpot specific optimization! HotSpot does not currently
2593 // support delegation from the bootstrap class loader to a
2594 // user-defined class loader. This means that if the bootstrap
2595 // class loader is the initiating class loader, then it will also
2596 // be the defining class loader. This also means that classes
2597 // loaded by the bootstrap class loader cannot refer to classes
2598 // loaded by a user-defined class loader. Note: a user-defined
2599 // class loader can delegate to the bootstrap class loader.
2600 //
2601 // If the current class being redefined has a user-defined class
2602 // loader as its defining class loader, then we can skip all
2603 // classes loaded by the bootstrap class loader.
2604 bool is_user_defined =
2605 InstanceKlass::cast(_the_class_oop)->class_loader() != NULL;
2606 if (is_user_defined && ik->class_loader() == NULL) {
2607 return;
2608 }
2609
2610 // If the class being redefined is java.lang.Object, we need to fix all
2611 // array class vtables also
2612 if (_the_class_oop == SystemDictionary::Object_klass()) {
2613 ik->array_klasses_do(adjust_array_vtable);
2614 }
2615
2616 // This is a very busy routine. We don't want too much tracing
2617 // printed out.
2618 bool trace_name_printed = false;
2619
2620 // Very noisy: only enable this call if you are trying to determine
2621 // that a specific class gets found by this routine.
2622 // RC_TRACE macro has an embedded ResourceMark
2623 // RC_TRACE_WITH_THREAD(0x00100000, THREAD,
2624 // ("adjust check: name=%s", ik->external_name()));
2625 // trace_name_printed = true;
2626
2627 // Fix the vtable embedded in the_class and subclasses of the_class,
2628 // if one exists. We discard scratch_class and we don't keep an
2629 // InstanceKlass around to hold obsolete methods so we don't have
2630 // any other InstanceKlass embedded vtables to update. The vtable
2631 // holds the Method*s for virtual (but not final) methods.
2632 if (ik->vtable_length() > 0 && ik->is_subtype_of(_the_class_oop)) {
2633 // ik->vtable() creates a wrapper object; rm cleans it up
2634 ResourceMark rm(THREAD);
2635 ik->vtable()->adjust_method_entries(_matching_old_methods,
2636 _matching_new_methods,
2637 _matching_methods_length,
2638 &trace_name_printed);
2639 }
2640
2641 // If the current class has an itable and we are either redefining an
2642 // interface or if the current class is a subclass of the_class, then
2643 // we potentially have to fix the itable. If we are redefining an
2644 // interface, then we have to call adjust_method_entries() for
2645 // every InstanceKlass that has an itable since there isn't a
2646 // subclass relationship between an interface and an InstanceKlass.
2647 if (ik->itable_length() > 0 && (_the_class_oop->is_interface()
2648 || ik->is_subclass_of(_the_class_oop))) {
2649 // ik->itable() creates a wrapper object; rm cleans it up
2650 ResourceMark rm(THREAD);
2651 ik->itable()->adjust_method_entries(_matching_old_methods,
2652 _matching_new_methods,
2653 _matching_methods_length,
2654 &trace_name_printed);
2655 }
2656
2657 // The constant pools in other classes (other_cp) can refer to
2658 // methods in the_class. We have to update method information in
2659 // other_cp's cache. If other_cp has a previous version, then we
2660 // have to repeat the process for each previous version. The
2661 // constant pool cache holds the Method*s for non-virtual
2662 // methods and for virtual, final methods.
2663 //
2664 // Special case: if the current class is the_class, then new_cp
2665 // has already been attached to the_class and old_cp has already
2666 // been added as a previous version. The new_cp doesn't have any
2667 // cached references to old methods so it doesn't need to be
2668 // updated. We can simply start with the previous version(s) in
2669 // that case.
2670 constantPoolHandle other_cp;
2671 ConstantPoolCache* cp_cache;
2672
2673 if (k_oop != _the_class_oop) {
2674 // this klass' constant pool cache may need adjustment
2675 other_cp = constantPoolHandle(ik->constants());
2676 cp_cache = other_cp->cache();
2677 if (cp_cache != NULL) {
2678 cp_cache->adjust_method_entries(_matching_old_methods,
2679 _matching_new_methods,
2680 _matching_methods_length,
2681 &trace_name_printed);
2682 }
2683 }
2684 {
2685 ResourceMark rm(THREAD);
2686 // PreviousVersionInfo objects returned via PreviousVersionWalker
2687 // contain a GrowableArray of handles. We have to clean up the
2688 // GrowableArray _after_ the PreviousVersionWalker destructor
2689 // has destroyed the handles.
2690 {
2691 // the previous versions' constant pool caches may need adjustment
2692 PreviousVersionWalker pvw(ik);
2693 for (PreviousVersionInfo * pv_info = pvw.next_previous_version();
2694 pv_info != NULL; pv_info = pvw.next_previous_version()) {
2695 other_cp = pv_info->prev_constant_pool_handle();
2696 cp_cache = other_cp->cache();
2697 if (cp_cache != NULL) {
2698 cp_cache->adjust_method_entries(_matching_old_methods,
2699 _matching_new_methods,
2700 _matching_methods_length,
2701 &trace_name_printed);
2702 }
2703 }
2704 } // pvw is cleaned up
2705 } // rm is cleaned up
2706 }
2707 }
2708
2709 void VM_RedefineClasses::update_jmethod_ids() {
2710 for (int j = 0; j < _matching_methods_length; ++j) {
2711 Method* old_method = _matching_old_methods[j];
2712 jmethodID jmid = old_method->find_jmethod_id_or_null();
2713 if (jmid != NULL) {
2714 // There is a jmethodID, change it to point to the new method
2715 methodHandle new_method_h(_matching_new_methods[j]);
2716 Method::change_method_associated_with_jmethod_id(jmid, new_method_h());
2717 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j],
2718 "should be replaced");
2719 }
2720 }
2721 }
2722
2723 void VM_RedefineClasses::check_methods_and_mark_as_obsolete(
2724 BitMap *emcp_methods, int * emcp_method_count_p) {
2725 *emcp_method_count_p = 0;
2726 int obsolete_count = 0;
2727 int old_index = 0;
2728 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
2729 Method* old_method = _matching_old_methods[j];
2730 Method* new_method = _matching_new_methods[j];
2731 Method* old_array_method;
2732
2733 // Maintain an old_index into the _old_methods array by skipping
2734 // deleted methods
2735 while ((old_array_method = _old_methods->at(old_index)) != old_method) {
2736 ++old_index;
2737 }
2738
2739 if (MethodComparator::methods_EMCP(old_method, new_method)) {
2740 // The EMCP definition from JSR-163 requires the bytecodes to be
2741 // the same with the exception of constant pool indices which may
2742 // differ. However, the constants referred to by those indices
2743 // must be the same.
2744 //
2745 // We use methods_EMCP() for comparison since constant pool
2746 // merging can remove duplicate constant pool entries that were
2747 // present in the old method and removed from the rewritten new
2748 // method. A faster binary comparison function would consider the
2749 // old and new methods to be different when they are actually
2750 // EMCP.
2751 //
2752 // The old and new methods are EMCP and you would think that we
2753 // could get rid of one of them here and now and save some space.
2754 // However, the concept of EMCP only considers the bytecodes and
2755 // the constant pool entries in the comparison. Other things,
2756 // e.g., the line number table (LNT) or the local variable table
2757 // (LVT) don't count in the comparison. So the new (and EMCP)
2758 // method can have a new LNT that we need so we can't just
2759 // overwrite the new method with the old method.
2760 //
2761 // When this routine is called, we have already attached the new
2762 // methods to the_class so the old methods are effectively
2763 // overwritten. However, if an old method is still executing,
2764 // then the old method cannot be collected until sometime after
2765 // the old method call has returned. So the overwriting of old
2766 // methods by new methods will save us space except for those
2767 // (hopefully few) old methods that are still executing.
2768 //
2769 // A method refers to a ConstMethod* and this presents another
2770 // possible avenue to space savings. The ConstMethod* in the
2771 // new method contains possibly new attributes (LNT, LVT, etc).
2772 // At first glance, it seems possible to save space by replacing
2773 // the ConstMethod* in the old method with the ConstMethod*
2774 // from the new method. The old and new methods would share the
2775 // same ConstMethod* and we would save the space occupied by
2776 // the old ConstMethod*. However, the ConstMethod* contains
2777 // a back reference to the containing method. Sharing the
2778 // ConstMethod* between two methods could lead to confusion in
2779 // the code that uses the back reference. This would lead to
2780 // brittle code that could be broken in non-obvious ways now or
2781 // in the future.
2782 //
2783 // Another possibility is to copy the ConstMethod* from the new
2784 // method to the old method and then overwrite the new method with
2785 // the old method. Since the ConstMethod* contains the bytecodes
2786 // for the method embedded in the oop, this option would change
2787 // the bytecodes out from under any threads executing the old
2788 // method and make the thread's bcp invalid. Since EMCP requires
2789 // that the bytecodes be the same modulo constant pool indices, it
2790 // is straight forward to compute the correct new bcp in the new
2791 // ConstMethod* from the old bcp in the old ConstMethod*. The
2792 // time consuming part would be searching all the frames in all
2793 // of the threads to find all of the calls to the old method.
2794 //
2795 // It looks like we will have to live with the limited savings
2796 // that we get from effectively overwriting the old methods
2797 // when the new methods are attached to the_class.
2798
2799 // track which methods are EMCP for add_previous_version() call
2800 emcp_methods->set_bit(old_index);
2801 (*emcp_method_count_p)++;
2802
2803 // An EMCP method is _not_ obsolete. An obsolete method has a
2804 // different jmethodID than the current method. An EMCP method
2805 // has the same jmethodID as the current method. Having the
2806 // same jmethodID for all EMCP versions of a method allows for
2807 // a consistent view of the EMCP methods regardless of which
2808 // EMCP method you happen to have in hand. For example, a
2809 // breakpoint set in one EMCP method will work for all EMCP
2810 // versions of the method including the current one.
2811 } else {
2812 // mark obsolete methods as such
2813 old_method->set_is_obsolete();
2814 obsolete_count++;
2815
2816 // obsolete methods need a unique idnum
2817 u2 num = InstanceKlass::cast(_the_class_oop)->next_method_idnum();
2818 if (num != ConstMethod::UNSET_IDNUM) {
2819 // u2 old_num = old_method->method_idnum();
2820 old_method->set_method_idnum(num);
2821 // TO DO: attach obsolete annotations to obsolete method's new idnum
2822 }
2823 // With tracing we try not to "yack" too much. The position of
2824 // this trace assumes there are fewer obsolete methods than
2825 // EMCP methods.
2826 RC_TRACE(0x00000100, ("mark %s(%s) as obsolete",
2827 old_method->name()->as_C_string(),
2828 old_method->signature()->as_C_string()));
2829 }
2830 old_method->set_is_old();
2831 }
2832 for (int i = 0; i < _deleted_methods_length; ++i) {
2833 Method* old_method = _deleted_methods[i];
2834
2835 assert(old_method->vtable_index() < 0,
2836 "cannot delete methods with vtable entries");;
2837
2838 // Mark all deleted methods as old and obsolete
2839 old_method->set_is_old();
2840 old_method->set_is_obsolete();
2841 ++obsolete_count;
2842 // With tracing we try not to "yack" too much. The position of
2843 // this trace assumes there are fewer obsolete methods than
2844 // EMCP methods.
2845 RC_TRACE(0x00000100, ("mark deleted %s(%s) as obsolete",
2846 old_method->name()->as_C_string(),
2847 old_method->signature()->as_C_string()));
2848 }
2849 assert((*emcp_method_count_p + obsolete_count) == _old_methods->length(),
2850 "sanity check");
2851 RC_TRACE(0x00000100, ("EMCP_cnt=%d, obsolete_cnt=%d", *emcp_method_count_p,
2852 obsolete_count));
2853 }
2854
2855 // This internal class transfers the native function registration from old methods
2856 // to new methods. It is designed to handle both the simple case of unchanged
2857 // native methods and the complex cases of native method prefixes being added and/or
2858 // removed.
2859 // It expects only to be used during the VM_RedefineClasses op (a safepoint).
2860 //
2861 // This class is used after the new methods have been installed in "the_class".
2862 //
2863 // So, for example, the following must be handled. Where 'm' is a method and
2864 // a number followed by an underscore is a prefix.
2865 //
2866 // Old Name New Name
2867 // Simple transfer to new method m -> m
2868 // Add prefix m -> 1_m
2869 // Remove prefix 1_m -> m
2870 // Simultaneous add of prefixes m -> 3_2_1_m
2871 // Simultaneous removal of prefixes 3_2_1_m -> m
2872 // Simultaneous add and remove 1_m -> 2_m
2873 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m
2874 //
2875 class TransferNativeFunctionRegistration {
2876 private:
2877 instanceKlassHandle the_class;
2878 int prefix_count;
2879 char** prefixes;
2880
2881 // Recursively search the binary tree of possibly prefixed method names.
2882 // Iteration could be used if all agents were well behaved. Full tree walk is
2883 // more resilent to agents not cleaning up intermediate methods.
2884 // Branch at each depth in the binary tree is:
2885 // (1) without the prefix.
2886 // (2) with the prefix.
2887 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
2888 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len,
2889 Symbol* signature) {
2890 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len);
2891 if (name_symbol != NULL) {
2892 Method* method = the_class()->lookup_method(name_symbol, signature);
2893 if (method != NULL) {
2894 // Even if prefixed, intermediate methods must exist.
2895 if (method->is_native()) {
2896 // Wahoo, we found a (possibly prefixed) version of the method, return it.
2897 return method;
2898 }
2899 if (depth < prefix_count) {
2900 // Try applying further prefixes (other than this one).
2901 method = search_prefix_name_space(depth+1, name_str, name_len, signature);
2902 if (method != NULL) {
2903 return method; // found
2904 }
2905
2906 // Try adding this prefix to the method name and see if it matches
2907 // another method name.
2908 char* prefix = prefixes[depth];
2909 size_t prefix_len = strlen(prefix);
2910 size_t trial_len = name_len + prefix_len;
2911 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
2912 strcpy(trial_name_str, prefix);
2913 strcat(trial_name_str, name_str);
2914 method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
2915 signature);
2916 if (method != NULL) {
2917 // If found along this branch, it was prefixed, mark as such
2918 method->set_is_prefixed_native();
2919 return method; // found
2920 }
2921 }
2922 }
2923 }
2924 return NULL; // This whole branch bore nothing
2925 }
2926
2927 // Return the method name with old prefixes stripped away.
2928 char* method_name_without_prefixes(Method* method) {
2929 Symbol* name = method->name();
2930 char* name_str = name->as_utf8();
2931
2932 // Old prefixing may be defunct, strip prefixes, if any.
2933 for (int i = prefix_count-1; i >= 0; i--) {
2934 char* prefix = prefixes[i];
2935 size_t prefix_len = strlen(prefix);
2936 if (strncmp(prefix, name_str, prefix_len) == 0) {
2937 name_str += prefix_len;
2938 }
2939 }
2940 return name_str;
2941 }
2942
2943 // Strip any prefixes off the old native method, then try to find a
2944 // (possibly prefixed) new native that matches it.
2945 Method* strip_and_search_for_new_native(Method* method) {
2946 ResourceMark rm;
2947 char* name_str = method_name_without_prefixes(method);
2948 return search_prefix_name_space(0, name_str, strlen(name_str),
2949 method->signature());
2950 }
2951
2952 public:
2953
2954 // Construct a native method transfer processor for this class.
2955 TransferNativeFunctionRegistration(instanceKlassHandle _the_class) {
2956 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
2957
2958 the_class = _the_class;
2959 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
2960 }
2961
2962 // Attempt to transfer any of the old or deleted methods that are native
2963 void transfer_registrations(Method** old_methods, int methods_length) {
2964 for (int j = 0; j < methods_length; j++) {
2965 Method* old_method = old_methods[j];
2966
2967 if (old_method->is_native() && old_method->has_native_function()) {
2968 Method* new_method = strip_and_search_for_new_native(old_method);
2969 if (new_method != NULL) {
2970 // Actually set the native function in the new method.
2971 // Redefine does not send events (except CFLH), certainly not this
2972 // behind the scenes re-registration.
2973 new_method->set_native_function(old_method->native_function(),
2974 !Method::native_bind_event_is_interesting);
2975 }
2976 }
2977 }
2978 }
2979 };
2980
2981 // Don't lose the association between a native method and its JNI function.
2982 void VM_RedefineClasses::transfer_old_native_function_registrations(instanceKlassHandle the_class) {
2983 TransferNativeFunctionRegistration transfer(the_class);
2984 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length);
2985 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length);
2986 }
2987
2988 // Deoptimize all compiled code that depends on this class.
2989 //
2990 // If the can_redefine_classes capability is obtained in the onload
2991 // phase then the compiler has recorded all dependencies from startup.
2992 // In that case we need only deoptimize and throw away all compiled code
2993 // that depends on the class.
2994 //
2995 // If can_redefine_classes is obtained sometime after the onload
2996 // phase then the dependency information may be incomplete. In that case
2997 // the first call to RedefineClasses causes all compiled code to be
2998 // thrown away. As can_redefine_classes has been obtained then
2999 // all future compilations will record dependencies so second and
3000 // subsequent calls to RedefineClasses need only throw away code
3001 // that depends on the class.
3002 //
3003 void VM_RedefineClasses::flush_dependent_code(instanceKlassHandle k_h, TRAPS) {
3004 assert_locked_or_safepoint(Compile_lock);
3005
3006 // All dependencies have been recorded from startup or this is a second or
3007 // subsequent use of RedefineClasses
3008 if (JvmtiExport::all_dependencies_are_recorded()) {
3009 Universe::flush_evol_dependents_on(k_h);
3010 } else {
3011 CodeCache::mark_all_nmethods_for_deoptimization();
3012
3013 ResourceMark rm(THREAD);
3014 DeoptimizationMarker dm;
3015
3016 // Deoptimize all activations depending on marked nmethods
3017 Deoptimization::deoptimize_dependents();
3018
3019 // Make the dependent methods not entrant (in VM_Deoptimize they are made zombies)
3020 CodeCache::make_marked_nmethods_not_entrant();
3021
3022 // From now on we know that the dependency information is complete
3023 JvmtiExport::set_all_dependencies_are_recorded(true);
3024 }
3025 }
3026
3027 void VM_RedefineClasses::compute_added_deleted_matching_methods() {
3028 Method* old_method;
3029 Method* new_method;
3030
3031 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3032 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3033 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length());
3034 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3035
3036 _matching_methods_length = 0;
3037 _deleted_methods_length = 0;
3038 _added_methods_length = 0;
3039
3040 int nj = 0;
3041 int oj = 0;
3042 while (true) {
3043 if (oj >= _old_methods->length()) {
3044 if (nj >= _new_methods->length()) {
3045 break; // we've looked at everything, done
3046 }
3047 // New method at the end
3048 new_method = _new_methods->at(nj);
3049 _added_methods[_added_methods_length++] = new_method;
3050 ++nj;
3051 } else if (nj >= _new_methods->length()) {
3052 // Old method, at the end, is deleted
3053 old_method = _old_methods->at(oj);
3054 _deleted_methods[_deleted_methods_length++] = old_method;
3055 ++oj;
3056 } else {
3057 old_method = _old_methods->at(oj);
3058 new_method = _new_methods->at(nj);
3059 if (old_method->name() == new_method->name()) {
3060 if (old_method->signature() == new_method->signature()) {
3061 _matching_old_methods[_matching_methods_length ] = old_method;
3062 _matching_new_methods[_matching_methods_length++] = new_method;
3063 ++nj;
3064 ++oj;
3065 } else {
3066 // added overloaded have already been moved to the end,
3067 // so this is a deleted overloaded method
3068 _deleted_methods[_deleted_methods_length++] = old_method;
3069 ++oj;
3070 }
3071 } else { // names don't match
3072 if (old_method->name()->fast_compare(new_method->name()) > 0) {
3073 // new method
3074 _added_methods[_added_methods_length++] = new_method;
3075 ++nj;
3076 } else {
3077 // deleted method
3078 _deleted_methods[_deleted_methods_length++] = old_method;
3079 ++oj;
3080 }
3081 }
3082 }
3083 }
3084 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
3085 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
3086 }
3087
3088
3089
3090 // Install the redefinition of a class:
3091 // - house keeping (flushing breakpoints and caches, deoptimizing
3092 // dependent compiled code)
3093 // - replacing parts in the_class with parts from scratch_class
3094 // - adding a weak reference to track the obsolete but interesting
3095 // parts of the_class
3096 // - adjusting constant pool caches and vtables in other classes
3097 // that refer to methods in the_class. These adjustments use the
3098 // SystemDictionary::classes_do() facility which only allows
3099 // a helper method to be specified. The interesting parameters
3100 // that we would like to pass to the helper method are saved in
3101 // static global fields in the VM operation.
3102 void VM_RedefineClasses::redefine_single_class(jclass the_jclass,
3103 Klass* scratch_class_oop, TRAPS) {
3104
3105 HandleMark hm(THREAD); // make sure handles from this call are freed
3106 RC_TIMER_START(_timer_rsc_phase1);
3107
3108 instanceKlassHandle scratch_class(scratch_class_oop);
3109
3110 oop the_class_mirror = JNIHandles::resolve_non_null(the_jclass);
3111 Klass* the_class_oop = java_lang_Class::as_Klass(the_class_mirror);
3112 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
3113
3114 // Remove all breakpoints in methods of this class
3115 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
3116 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class_oop);
3117
3118 if (the_class_oop == Universe::reflect_invoke_cache()->klass()) {
3119 // We are redefining java.lang.reflect.Method. Method.invoke() is
3120 // cached and users of the cache care about each active version of
3121 // the method so we have to track this previous version.
3122 // Do this before methods get switched
3123 Universe::reflect_invoke_cache()->add_previous_version(
3124 the_class->method_with_idnum(Universe::reflect_invoke_cache()->method_idnum()));
3125 }
3126
3127 // Deoptimize all compiled code that depends on this class
3128 flush_dependent_code(the_class, THREAD);
3129
3130 _old_methods = the_class->methods();
3131 _new_methods = scratch_class->methods();
3132 _the_class_oop = the_class_oop;
3133 compute_added_deleted_matching_methods();
3134 update_jmethod_ids();
3135
3136 // Attach new constant pool to the original klass. The original
3137 // klass still refers to the old constant pool (for now).
3138 scratch_class->constants()->set_pool_holder(the_class());
3139
3140 #if 0
3141 // In theory, with constant pool merging in place we should be able
3142 // to save space by using the new, merged constant pool in place of
3143 // the old constant pool(s). By "pool(s)" I mean the constant pool in
3144 // the klass version we are replacing now and any constant pool(s) in
3145 // previous versions of klass. Nice theory, doesn't work in practice.
3146 // When this code is enabled, even simple programs throw NullPointer
3147 // exceptions. I'm guessing that this is caused by some constant pool
3148 // cache difference between the new, merged constant pool and the
3149 // constant pool that was just being used by the klass. I'm keeping
3150 // this code around to archive the idea, but the code has to remain
3151 // disabled for now.
3152
3153 // Attach each old method to the new constant pool. This can be
3154 // done here since we are past the bytecode verification and
3155 // constant pool optimization phases.
3156 for (int i = _old_methods->length() - 1; i >= 0; i--) {
3157 Method* method = _old_methods->at(i);
3158 method->set_constants(scratch_class->constants());
3159 }
3160
3161 {
3162 // walk all previous versions of the klass
3163 InstanceKlass *ik = (InstanceKlass *)the_class();
3164 PreviousVersionWalker pvw(ik);
3165 instanceKlassHandle ikh;
3166 do {
3167 ikh = pvw.next_previous_version();
3168 if (!ikh.is_null()) {
3169 ik = ikh();
3170
3171 // attach previous version of klass to the new constant pool
3172 ik->set_constants(scratch_class->constants());
3173
3174 // Attach each method in the previous version of klass to the
3175 // new constant pool
3176 Array<Method*>* prev_methods = ik->methods();
3177 for (int i = prev_methods->length() - 1; i >= 0; i--) {
3178 Method* method = prev_methods->at(i);
3179 method->set_constants(scratch_class->constants());
3180 }
3181 }
3182 } while (!ikh.is_null());
3183 }
3184 #endif
3185
3186 // Replace methods and constantpool
3187 the_class->set_methods(_new_methods);
3188 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods,
3189 // and to be able to undo operation easily.
3190
3191 ConstantPool* old_constants = the_class->constants();
3192 the_class->set_constants(scratch_class->constants());
3193 scratch_class->set_constants(old_constants); // See the previous comment.
3194 #if 0
3195 // We are swapping the guts of "the new class" with the guts of "the
3196 // class". Since the old constant pool has just been attached to "the
3197 // new class", it seems logical to set the pool holder in the old
3198 // constant pool also. However, doing this will change the observable
3199 // class hierarchy for any old methods that are still executing. A
3200 // method can query the identity of its "holder" and this query uses
3201 // the method's constant pool link to find the holder. The change in
3202 // holding class from "the class" to "the new class" can confuse
3203 // things.
3204 //
3205 // Setting the old constant pool's holder will also cause
3206 // verification done during vtable initialization below to fail.
3207 // During vtable initialization, the vtable's class is verified to be
3208 // a subtype of the method's holder. The vtable's class is "the
3209 // class" and the method's holder is gotten from the constant pool
3210 // link in the method itself. For "the class"'s directly implemented
3211 // methods, the method holder is "the class" itself (as gotten from
3212 // the new constant pool). The check works fine in this case. The
3213 // check also works fine for methods inherited from super classes.
3214 //
3215 // Miranda methods are a little more complicated. A miranda method is
3216 // provided by an interface when the class implementing the interface
3217 // does not provide its own method. These interfaces are implemented
3218 // internally as an InstanceKlass. These special instanceKlasses
3219 // share the constant pool of the class that "implements" the
3220 // interface. By sharing the constant pool, the method holder of a
3221 // miranda method is the class that "implements" the interface. In a
3222 // non-redefine situation, the subtype check works fine. However, if
3223 // the old constant pool's pool holder is modified, then the check
3224 // fails because there is no class hierarchy relationship between the
3225 // vtable's class and "the new class".
3226
3227 old_constants->set_pool_holder(scratch_class());
3228 #endif
3229
3230 // track which methods are EMCP for add_previous_version() call below
3231 BitMap emcp_methods(_old_methods->length());
3232 int emcp_method_count = 0;
3233 emcp_methods.clear(); // clears 0..(length() - 1)
3234 check_methods_and_mark_as_obsolete(&emcp_methods, &emcp_method_count);
3235 transfer_old_native_function_registrations(the_class);
3236
3237 // The class file bytes from before any retransformable agents mucked
3238 // with them was cached on the scratch class, move to the_class.
3239 // Note: we still want to do this if nothing needed caching since it
3240 // should get cleared in the_class too.
3241 if (the_class->get_cached_class_file_bytes() == 0) {
3242 // the_class doesn't have a cache yet so copy it
3243 the_class->set_cached_class_file(
3244 scratch_class->get_cached_class_file_bytes(),
3245 scratch_class->get_cached_class_file_len());
3246 }
3247 #ifndef PRODUCT
3248 else {
3249 assert(the_class->get_cached_class_file_bytes() ==
3250 scratch_class->get_cached_class_file_bytes(), "cache ptrs must match");
3251 assert(the_class->get_cached_class_file_len() ==
3252 scratch_class->get_cached_class_file_len(), "cache lens must match");
3253 }
3254 #endif
3255
3256 // Replace inner_classes
3257 Array<u2>* old_inner_classes = the_class->inner_classes();
3258 the_class->set_inner_classes(scratch_class->inner_classes());
3259 scratch_class->set_inner_classes(old_inner_classes);
3260
3261 // Initialize the vtable and interface table after
3262 // methods have been rewritten
3263 {
3264 ResourceMark rm(THREAD);
3265 // no exception should happen here since we explicitly
3266 // do not check loader constraints.
3267 // compare_and_normalize_class_versions has already checked:
3268 // - classloaders unchanged, signatures unchanged
3269 // - all instanceKlasses for redefined classes reused & contents updated
3270 the_class->vtable()->initialize_vtable(false, THREAD);
3271 the_class->itable()->initialize_itable(false, THREAD);
3272 assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())), "redefine exception");
3273 }
3274
3275 // Leave arrays of jmethodIDs and itable index cache unchanged
3276
3277 // Copy the "source file name" attribute from new class version
3278 the_class->set_source_file_name(scratch_class->source_file_name());
3279
3280 // Copy the "source debug extension" attribute from new class version
3281 the_class->set_source_debug_extension(
3282 scratch_class->source_debug_extension(),
3283 scratch_class->source_debug_extension() == NULL ? 0 :
3284 (int)strlen(scratch_class->source_debug_extension()));
3285
3286 // Use of javac -g could be different in the old and the new
3287 if (scratch_class->access_flags().has_localvariable_table() !=
3288 the_class->access_flags().has_localvariable_table()) {
3289
3290 AccessFlags flags = the_class->access_flags();
3291 if (scratch_class->access_flags().has_localvariable_table()) {
3292 flags.set_has_localvariable_table();
3293 } else {
3294 flags.clear_has_localvariable_table();
3295 }
3296 the_class->set_access_flags(flags);
3297 }
3298
3299 // Since there is currently no rewriting of type annotations indexes
3300 // into the CP, we null out type annotations on scratch_class before
3301 // we swap annotations with the_class rather than facing the
3302 // possibility of shipping annotations with broken indexes to
3303 // Java-land.
3304 Annotations* new_annotations = scratch_class->annotations();
3305 if (new_annotations != NULL) {
3306 Annotations* new_type_annotations = new_annotations->type_annotations();
3307 if (new_type_annotations != NULL) {
3308 MetadataFactory::free_metadata(scratch_class->class_loader_data(), new_type_annotations);
3309 new_annotations->set_type_annotations(NULL);
3310 }
3311 }
3312 // Swap annotation fields values
3313 Annotations* old_annotations = the_class->annotations();
3314 the_class->set_annotations(scratch_class->annotations());
3315 scratch_class->set_annotations(old_annotations);
3316
3317 // Replace minor version number of class file
3318 u2 old_minor_version = the_class->minor_version();
3319 the_class->set_minor_version(scratch_class->minor_version());
3320 scratch_class->set_minor_version(old_minor_version);
3321
3322 // Replace major version number of class file
3323 u2 old_major_version = the_class->major_version();
3324 the_class->set_major_version(scratch_class->major_version());
3325 scratch_class->set_major_version(old_major_version);
3326
3327 // Replace CP indexes for class and name+type of enclosing method
3328 u2 old_class_idx = the_class->enclosing_method_class_index();
3329 u2 old_method_idx = the_class->enclosing_method_method_index();
3330 the_class->set_enclosing_method_indices(
3331 scratch_class->enclosing_method_class_index(),
3332 scratch_class->enclosing_method_method_index());
3333 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx);
3334
3335 // keep track of previous versions of this class
3336 the_class->add_previous_version(scratch_class, &emcp_methods,
3337 emcp_method_count);
3338
3339 RC_TIMER_STOP(_timer_rsc_phase1);
3340 RC_TIMER_START(_timer_rsc_phase2);
3341
3342 // Adjust constantpool caches and vtables for all classes
3343 // that reference methods of the evolved class.
3344 SystemDictionary::classes_do(adjust_cpool_cache_and_vtable, THREAD);
3345
3346 // Fix Resolution Error table also to remove old constant pools
3347 SystemDictionary::delete_resolution_error(old_constants);
3348
3349 if (the_class->oop_map_cache() != NULL) {
3350 // Flush references to any obsolete methods from the oop map cache
3351 // so that obsolete methods are not pinned.
3352 the_class->oop_map_cache()->flush_obsolete_entries();
3353 }
3354
3355 // increment the classRedefinedCount field in the_class and in any
3356 // direct and indirect subclasses of the_class
3357 increment_class_counter((InstanceKlass *)the_class(), THREAD);
3358
3359 // RC_TRACE macro has an embedded ResourceMark
3360 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
3361 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)",
3362 the_class->external_name(),
3363 java_lang_Class::classRedefinedCount(the_class_mirror),
3364 os::available_memory() >> 10));
3365
3366 RC_TIMER_STOP(_timer_rsc_phase2);
3367 } // end redefine_single_class()
3368
3369
3370 // Increment the classRedefinedCount field in the specific InstanceKlass
3371 // and in all direct and indirect subclasses.
3372 void VM_RedefineClasses::increment_class_counter(InstanceKlass *ik, TRAPS) {
3373 oop class_mirror = ik->java_mirror();
3374 Klass* class_oop = java_lang_Class::as_Klass(class_mirror);
3375 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
3376 java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
3377
3378 if (class_oop != _the_class_oop) {
3379 // _the_class_oop count is printed at end of redefine_single_class()
3380 RC_TRACE_WITH_THREAD(0x00000008, THREAD,
3381 ("updated count in subclass=%s to %d", ik->external_name(), new_count));
3382 }
3383
3384 for (Klass *subk = ik->subklass(); subk != NULL;
3385 subk = subk->next_sibling()) {
3386 if (subk->oop_is_instance()) {
3387 // Only update instanceKlasses
3388 InstanceKlass *subik = (InstanceKlass*)subk;
3389 // recursively do subclasses of the current subclass
3390 increment_class_counter(subik, THREAD);
3391 }
3392 }
3393 }
3394
3395 #ifndef PRODUCT
3396 void VM_RedefineClasses::check_class(Klass* k_oop,
3397 ClassLoaderData* initiating_loader,
3398 TRAPS) {
3399 Klass *k = k_oop;
3400 if (k->oop_is_instance()) {
3401 HandleMark hm(THREAD);
3402 InstanceKlass *ik = (InstanceKlass *) k;
3403
3404 if (ik->vtable_length() > 0) {
3405 ResourceMark rm(THREAD);
3406 if (!ik->vtable()->check_no_old_entries()) {
3407 tty->print_cr("klassVtable::check_no_old_entries failure -- OLD method found -- class: %s", ik->signature_name());
3408 ik->vtable()->dump_vtable();
3409 assert(false, "OLD method found");
3410 }
3411 }
3412 if (ik->itable_length() > 0) {
3413 ResourceMark rm(THREAD);
3414 if (!ik->itable()->check_no_old_entries()) {
3415 tty->print_cr("klassItable::check_no_old_entries failure -- OLD method found -- class: %s", ik->signature_name());
3416 assert(false, "OLD method found");
3417 }
3418 }
3419 // Check that the constant pool cache has no deleted entries.
3420 if (ik->constants() != NULL &&
3421 ik->constants()->cache() != NULL &&
3422 !ik->constants()->cache()->check_no_old_entries()) {
3423 tty->print_cr("klassVtable::check_no_old_entries failure -- OLD method found -- class: %s", ik->signature_name());
3424 assert(false, "OLD method found");
3425 }
3426 }
3427 }
3428
3429 void VM_RedefineClasses::dump_methods() {
3430 int j;
3431 tty->print_cr("_old_methods --");
3432 for (j = 0; j < _old_methods->length(); ++j) {
3433 Method* m = _old_methods->at(j);
3434 tty->print("%4d (%5d) ", j, m->vtable_index());
3435 m->access_flags().print_on(tty);
3436 tty->print(" -- ");
3437 m->print_name(tty);
3438 tty->cr();
3439 }
3440 tty->print_cr("_new_methods --");
3441 for (j = 0; j < _new_methods->length(); ++j) {
3442 Method* m = _new_methods->at(j);
3443 tty->print("%4d (%5d) ", j, m->vtable_index());
3444 m->access_flags().print_on(tty);
3445 tty->print(" -- ");
3446 m->print_name(tty);
3447 tty->cr();
3448 }
3449 tty->print_cr("_matching_(old/new)_methods --");
3450 for (j = 0; j < _matching_methods_length; ++j) {
3451 Method* m = _matching_old_methods[j];
3452 tty->print("%4d (%5d) ", j, m->vtable_index());
3453 m->access_flags().print_on(tty);
3454 tty->print(" -- ");
3455 m->print_name(tty);
3456 tty->cr();
3457 m = _matching_new_methods[j];
3458 tty->print(" (%5d) ", m->vtable_index());
3459 m->access_flags().print_on(tty);
3460 tty->cr();
3461 }
3462 tty->print_cr("_deleted_methods --");
3463 for (j = 0; j < _deleted_methods_length; ++j) {
3464 Method* m = _deleted_methods[j];
3465 tty->print("%4d (%5d) ", j, m->vtable_index());
3466 m->access_flags().print_on(tty);
3467 tty->print(" -- ");
3468 m->print_name(tty);
3469 tty->cr();
3470 }
3471 tty->print_cr("_added_methods --");
3472 for (j = 0; j < _added_methods_length; ++j) {
3473 Method* m = _added_methods[j];
3474 tty->print("%4d (%5d) ", j, m->vtable_index());
3475 m->access_flags().print_on(tty);
3476 tty->print(" -- ");
3477 m->print_name(tty);
3478 tty->cr();
3479 }
3480 }
3481 #endif
--- EOF ---