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 = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p,
282 merge_cp_length_p, THREAD);
283
284 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i);
285 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i,
286 merge_cp_p, merge_cp_length_p,
287 THREAD);
288
289 // If the referenced entries already exist in *merge_cp_p, then
290 // both new_name_ref_i and new_signature_ref_i will both be 0.
291 // In that case, all we are appending is the current entry.
292 if (new_name_ref_i != name_ref_i) {
293 RC_TRACE(0x00080000,
294 ("NameAndType entry@%d name_ref_index change: %d to %d",
295 *merge_cp_length_p, name_ref_i, new_name_ref_i));
296 }
297 if (new_signature_ref_i != signature_ref_i) {
298 RC_TRACE(0x00080000,
299 ("NameAndType entry@%d signature_ref_index change: %d to %d",
300 *merge_cp_length_p, signature_ref_i, new_signature_ref_i));
301 }
302
303 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p,
304 new_name_ref_i, new_signature_ref_i);
305 if (scratch_i != *merge_cp_length_p) {
306 // The new entry in *merge_cp_p is at a different index than
307 // the new entry in scratch_cp so we need to map the index values.
308 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
309 }
310 (*merge_cp_length_p)++;
311 } break;
312
313 // this is a double-indirect CP entry so it needs special handling
314 case JVM_CONSTANT_Fieldref: // fall through
315 case JVM_CONSTANT_InterfaceMethodref: // fall through
316 case JVM_CONSTANT_Methodref:
317 {
318 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i);
319 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i,
320 merge_cp_p, merge_cp_length_p, THREAD);
321
322 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i);
323 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i,
324 merge_cp_p, merge_cp_length_p, THREAD);
325
326 const char *entry_name;
327 switch (scratch_cp->tag_at(scratch_i).value()) {
328 case JVM_CONSTANT_Fieldref:
329 entry_name = "Fieldref";
330 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i,
331 new_name_and_type_ref_i);
332 break;
333 case JVM_CONSTANT_InterfaceMethodref:
334 entry_name = "IFMethodref";
335 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p,
336 new_klass_ref_i, new_name_and_type_ref_i);
337 break;
338 case JVM_CONSTANT_Methodref:
339 entry_name = "Methodref";
340 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i,
341 new_name_and_type_ref_i);
342 break;
343 default:
344 guarantee(false, "bad switch");
345 break;
346 }
347
348 if (klass_ref_i != new_klass_ref_i) {
349 RC_TRACE(0x00080000, ("%s entry@%d class_index changed: %d to %d",
350 entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i));
351 }
352 if (name_and_type_ref_i != new_name_and_type_ref_i) {
353 RC_TRACE(0x00080000,
354 ("%s entry@%d name_and_type_index changed: %d to %d",
355 entry_name, *merge_cp_length_p, name_and_type_ref_i,
356 new_name_and_type_ref_i));
357 }
358
359 if (scratch_i != *merge_cp_length_p) {
360 // The new entry in *merge_cp_p is at a different index than
361 // the new entry in scratch_cp so we need to map the index values.
362 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
363 }
364 (*merge_cp_length_p)++;
365 } break;
366
367 // this is an indirect CP entry so it needs special handling
368 case JVM_CONSTANT_MethodType:
369 {
370 int ref_i = scratch_cp->method_type_index_at(scratch_i);
371 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
372 merge_cp_length_p, THREAD);
373 if (new_ref_i != ref_i) {
374 RC_TRACE(0x00080000,
375 ("MethodType entry@%d ref_index change: %d to %d",
376 *merge_cp_length_p, ref_i, new_ref_i));
377 }
378 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i);
379 if (scratch_i != *merge_cp_length_p) {
380 // The new entry in *merge_cp_p is at a different index than
381 // the new entry in scratch_cp so we need to map the index values.
382 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
383 }
384 (*merge_cp_length_p)++;
385 } break;
386
387 // this is an indirect CP entry so it needs special handling
388 case JVM_CONSTANT_MethodHandle:
389 {
390 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i);
391 int ref_i = scratch_cp->method_handle_index_at(scratch_i);
392 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
393 merge_cp_length_p, THREAD);
394 if (new_ref_i != ref_i) {
395 RC_TRACE(0x00080000,
396 ("MethodHandle entry@%d ref_index change: %d to %d",
397 *merge_cp_length_p, ref_i, new_ref_i));
398 }
399 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i);
400 if (scratch_i != *merge_cp_length_p) {
401 // The new entry in *merge_cp_p is at a different index than
402 // the new entry in scratch_cp so we need to map the index values.
403 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
404 }
405 (*merge_cp_length_p)++;
406 } break;
407
408 // this is an indirect CP entry so it needs special handling
409 case JVM_CONSTANT_InvokeDynamic:
410 {
411 // TBD: cross-checks and possible extra appends into CP and bsm operands
412 // are needed as well. This issue is tracked by a separate bug 8007037.
413 int bss_idx = scratch_cp->invoke_dynamic_bootstrap_specifier_index(scratch_i);
414
415 int ref_i = scratch_cp->invoke_dynamic_name_and_type_ref_index_at(scratch_i);
416 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
417 merge_cp_length_p, THREAD);
418 if (new_ref_i != ref_i) {
419 RC_TRACE(0x00080000,
420 ("InvokeDynamic entry@%d name_and_type ref_index change: %d to %d",
421 *merge_cp_length_p, ref_i, new_ref_i));
422 }
423
424 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, bss_idx, new_ref_i);
425 if (scratch_i != *merge_cp_length_p) {
426 // The new entry in *merge_cp_p is at a different index than
427 // the new entry in scratch_cp so we need to map the index values.
428 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
429 }
430 (*merge_cp_length_p)++;
431 } break;
432
433 // At this stage, Class or UnresolvedClass could be here, but not
434 // ClassIndex
435 case JVM_CONSTANT_ClassIndex: // fall through
436
437 // Invalid is used as the tag for the second constant pool entry
438 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
439 // not be seen by itself.
440 case JVM_CONSTANT_Invalid: // fall through
441
442 // At this stage, String could be here, but not StringIndex
443 case JVM_CONSTANT_StringIndex: // fall through
444
445 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be
446 // here
447 case JVM_CONSTANT_UnresolvedClassInError: // fall through
448
449 default:
450 {
451 // leave a breadcrumb
452 jbyte bad_value = scratch_cp->tag_at(scratch_i).value();
453 ShouldNotReachHere();
454 } break;
455 } // end switch tag value
456 } // end append_entry()
457
458
459 int VM_RedefineClasses::find_or_append_indirect_entry(constantPoolHandle scratch_cp,
460 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
461
462 int new_ref_i = ref_i;
463 bool match = (ref_i < *merge_cp_length_p) &&
464 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i, THREAD);
465
466 if (!match) {
467 // forward reference in *merge_cp_p or not a direct match
468 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p, THREAD);
469 if (found_i != 0) {
470 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree");
471 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry.
472 new_ref_i = found_i;
473 map_index(scratch_cp, ref_i, found_i);
474 } else {
475 // no match found so we have to append this entry to *merge_cp_p
476 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p, THREAD);
477 // The above call to append_entry() can only append one entry
478 // so the post call query of *merge_cp_length_p is only for
479 // the sake of consistency.
480 new_ref_i = *merge_cp_length_p - 1;
481 }
482 }
483
484 return new_ref_i;
485 } // end find_or_append_indirect_entry()
486
487
488 void VM_RedefineClasses::swap_all_method_annotations(int i, int j, instanceKlassHandle scratch_class, TRAPS) {
489 AnnotationArray* save;
490
491 Annotations* sca = scratch_class->annotations();
492 if (sca == NULL) return;
493
494 save = sca->get_method_annotations_of(i);
495 sca->set_method_annotations_of(scratch_class, i, sca->get_method_annotations_of(j), CHECK);
496 sca->set_method_annotations_of(scratch_class, j, save, CHECK);
497
498 save = sca->get_method_parameter_annotations_of(i);
499 sca->set_method_parameter_annotations_of(scratch_class, i, sca->get_method_parameter_annotations_of(j), CHECK);
500 sca->set_method_parameter_annotations_of(scratch_class, j, save, CHECK);
501
502 save = sca->get_method_default_annotations_of(i);
503 sca->set_method_default_annotations_of(scratch_class, i, sca->get_method_default_annotations_of(j), CHECK);
504 sca->set_method_default_annotations_of(scratch_class, j, save, CHECK);
505 }
506
507
508 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions(
509 instanceKlassHandle the_class,
510 instanceKlassHandle scratch_class) {
511 int i;
512
513 // Check superclasses, or rather their names, since superclasses themselves can be
514 // requested to replace.
515 // Check for NULL superclass first since this might be java.lang.Object
516 if (the_class->super() != scratch_class->super() &&
517 (the_class->super() == NULL || scratch_class->super() == NULL ||
518 the_class->super()->name() !=
519 scratch_class->super()->name())) {
520 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
521 }
522
523 // Check if the number, names and order of directly implemented interfaces are the same.
524 // I think in principle we should just check if the sets of names of directly implemented
525 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the
526 // .java file, also changes in .class file) should not matter. However, comparing sets is
527 // technically a bit more difficult, and, more importantly, I am not sure at present that the
528 // order of interfaces does not matter on the implementation level, i.e. that the VM does not
529 // rely on it somewhere.
530 Array<Klass*>* k_interfaces = the_class->local_interfaces();
531 Array<Klass*>* k_new_interfaces = scratch_class->local_interfaces();
532 int n_intfs = k_interfaces->length();
533 if (n_intfs != k_new_interfaces->length()) {
534 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
535 }
536 for (i = 0; i < n_intfs; i++) {
537 if (k_interfaces->at(i)->name() !=
538 k_new_interfaces->at(i)->name()) {
539 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
540 }
541 }
542
543 // Check whether class is in the error init state.
544 if (the_class->is_in_error_state()) {
545 // TBD #5057930: special error code is needed in 1.6
546 return JVMTI_ERROR_INVALID_CLASS;
547 }
548
549 // Check whether class modifiers are the same.
550 jushort old_flags = (jushort) the_class->access_flags().get_flags();
551 jushort new_flags = (jushort) scratch_class->access_flags().get_flags();
552 if (old_flags != new_flags) {
553 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED;
554 }
555
556 // Check if the number, names, types and order of fields declared in these classes
557 // are the same.
558 JavaFieldStream old_fs(the_class);
559 JavaFieldStream new_fs(scratch_class);
560 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) {
561 // access
562 old_flags = old_fs.access_flags().as_short();
563 new_flags = new_fs.access_flags().as_short();
564 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) {
565 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
566 }
567 // offset
568 if (old_fs.offset() != new_fs.offset()) {
569 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
570 }
571 // name and signature
572 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index());
573 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index());
574 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index());
575 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index());
576 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) {
577 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
578 }
579 }
580
581 // If both streams aren't done then we have a differing number of
582 // fields.
583 if (!old_fs.done() || !new_fs.done()) {
584 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
585 }
586
587 // Do a parallel walk through the old and new methods. Detect
588 // cases where they match (exist in both), have been added in
589 // the new methods, or have been deleted (exist only in the
590 // old methods). The class file parser places methods in order
591 // by method name, but does not order overloaded methods by
592 // signature. In order to determine what fate befell the methods,
593 // this code places the overloaded new methods that have matching
594 // old methods in the same order as the old methods and places
595 // new overloaded methods at the end of overloaded methods of
596 // that name. The code for this order normalization is adapted
597 // from the algorithm used in InstanceKlass::find_method().
598 // Since we are swapping out of order entries as we find them,
599 // we only have to search forward through the overloaded methods.
600 // Methods which are added and have the same name as an existing
601 // method (but different signature) will be put at the end of
602 // the methods with that name, and the name mismatch code will
603 // handle them.
604 Array<Method*>* k_old_methods(the_class->methods());
605 Array<Method*>* k_new_methods(scratch_class->methods());
606 int n_old_methods = k_old_methods->length();
607 int n_new_methods = k_new_methods->length();
608 Thread* thread = Thread::current();
609
610 int ni = 0;
611 int oi = 0;
612 while (true) {
613 Method* k_old_method;
614 Method* k_new_method;
615 enum { matched, added, deleted, undetermined } method_was = undetermined;
616
617 if (oi >= n_old_methods) {
618 if (ni >= n_new_methods) {
619 break; // we've looked at everything, done
620 }
621 // New method at the end
622 k_new_method = k_new_methods->at(ni);
623 method_was = added;
624 } else if (ni >= n_new_methods) {
625 // Old method, at the end, is deleted
626 k_old_method = k_old_methods->at(oi);
627 method_was = deleted;
628 } else {
629 // There are more methods in both the old and new lists
630 k_old_method = k_old_methods->at(oi);
631 k_new_method = k_new_methods->at(ni);
632 if (k_old_method->name() != k_new_method->name()) {
633 // Methods are sorted by method name, so a mismatch means added
634 // or deleted
635 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) {
636 method_was = added;
637 } else {
638 method_was = deleted;
639 }
640 } else if (k_old_method->signature() == k_new_method->signature()) {
641 // Both the name and signature match
642 method_was = matched;
643 } else {
644 // The name matches, but the signature doesn't, which means we have to
645 // search forward through the new overloaded methods.
646 int nj; // outside the loop for post-loop check
647 for (nj = ni + 1; nj < n_new_methods; nj++) {
648 Method* m = k_new_methods->at(nj);
649 if (k_old_method->name() != m->name()) {
650 // reached another method name so no more overloaded methods
651 method_was = deleted;
652 break;
653 }
654 if (k_old_method->signature() == m->signature()) {
655 // found a match so swap the methods
656 k_new_methods->at_put(ni, m);
657 k_new_methods->at_put(nj, k_new_method);
658 k_new_method = m;
659 method_was = matched;
660 break;
661 }
662 }
663
664 if (nj >= n_new_methods) {
665 // reached the end without a match; so method was deleted
666 method_was = deleted;
667 }
668 }
669 }
670
671 switch (method_was) {
672 case matched:
673 // methods match, be sure modifiers do too
674 old_flags = (jushort) k_old_method->access_flags().get_flags();
675 new_flags = (jushort) k_new_method->access_flags().get_flags();
676 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) {
677 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED;
678 }
679 {
680 u2 new_num = k_new_method->method_idnum();
681 u2 old_num = k_old_method->method_idnum();
682 if (new_num != old_num) {
683 Method* idnum_owner = scratch_class->method_with_idnum(old_num);
684 if (idnum_owner != NULL) {
685 // There is already a method assigned this idnum -- switch them
686 idnum_owner->set_method_idnum(new_num);
687 }
688 k_new_method->set_method_idnum(old_num);
689 swap_all_method_annotations(old_num, new_num, scratch_class, thread);
690 if (thread->has_pending_exception()) {
691 return JVMTI_ERROR_OUT_OF_MEMORY;
692 }
693 }
694 }
695 RC_TRACE(0x00008000, ("Method matched: new: %s [%d] == old: %s [%d]",
696 k_new_method->name_and_sig_as_C_string(), ni,
697 k_old_method->name_and_sig_as_C_string(), oi));
698 // advance to next pair of methods
699 ++oi;
700 ++ni;
701 break;
702 case added:
703 // method added, see if it is OK
704 new_flags = (jushort) k_new_method->access_flags().get_flags();
705 if ((new_flags & JVM_ACC_PRIVATE) == 0
706 // hack: private should be treated as final, but alas
707 || (new_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
708 ) {
709 // new methods must be private
710 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
711 }
712 {
713 u2 num = the_class->next_method_idnum();
714 if (num == ConstMethod::UNSET_IDNUM) {
715 // cannot add any more methods
716 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
717 }
718 u2 new_num = k_new_method->method_idnum();
719 Method* idnum_owner = scratch_class->method_with_idnum(num);
720 if (idnum_owner != NULL) {
721 // There is already a method assigned this idnum -- switch them
722 idnum_owner->set_method_idnum(new_num);
723 }
724 k_new_method->set_method_idnum(num);
725 swap_all_method_annotations(new_num, num, scratch_class, thread);
726 if (thread->has_pending_exception()) {
727 return JVMTI_ERROR_OUT_OF_MEMORY;
728 }
729 }
730 RC_TRACE(0x00008000, ("Method added: new: %s [%d]",
731 k_new_method->name_and_sig_as_C_string(), ni));
732 ++ni; // advance to next new method
733 break;
734 case deleted:
735 // method deleted, see if it is OK
736 old_flags = (jushort) k_old_method->access_flags().get_flags();
737 if ((old_flags & JVM_ACC_PRIVATE) == 0
738 // hack: private should be treated as final, but alas
739 || (old_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
740 ) {
741 // deleted methods must be private
742 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED;
743 }
744 RC_TRACE(0x00008000, ("Method deleted: old: %s [%d]",
745 k_old_method->name_and_sig_as_C_string(), oi));
746 ++oi; // advance to next old method
747 break;
748 default:
749 ShouldNotReachHere();
750 }
751 }
752
753 return JVMTI_ERROR_NONE;
754 }
755
756
757 // Find new constant pool index value for old constant pool index value
758 // by seaching the index map. Returns zero (0) if there is no mapped
759 // value for the old constant pool index.
760 int VM_RedefineClasses::find_new_index(int old_index) {
761 if (_index_map_count == 0) {
762 // map is empty so nothing can be found
763 return 0;
764 }
765
766 if (old_index < 1 || old_index >= _index_map_p->length()) {
767 // The old_index is out of range so it is not mapped. This should
768 // not happen in regular constant pool merging use, but it can
769 // happen if a corrupt annotation is processed.
770 return 0;
771 }
772
773 int value = _index_map_p->at(old_index);
774 if (value == -1) {
775 // the old_index is not mapped
776 return 0;
777 }
778
779 return value;
780 } // end find_new_index()
781
782
783 // Returns true if the current mismatch is due to a resolved/unresolved
784 // class pair. Otherwise, returns false.
785 bool VM_RedefineClasses::is_unresolved_class_mismatch(constantPoolHandle cp1,
786 int index1, constantPoolHandle cp2, int index2) {
787
788 jbyte t1 = cp1->tag_at(index1).value();
789 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) {
790 return false; // wrong entry type; not our special case
791 }
792
793 jbyte t2 = cp2->tag_at(index2).value();
794 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) {
795 return false; // wrong entry type; not our special case
796 }
797
798 if (t1 == t2) {
799 return false; // not a mismatch; not our special case
800 }
801
802 char *s1 = cp1->klass_name_at(index1)->as_C_string();
803 char *s2 = cp2->klass_name_at(index2)->as_C_string();
804 if (strcmp(s1, s2) != 0) {
805 return false; // strings don't match; not our special case
806 }
807
808 return true; // made it through the gauntlet; this is our special case
809 } // end is_unresolved_class_mismatch()
810
811
812 jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) {
813
814 // For consistency allocate memory using os::malloc wrapper.
815 _scratch_classes = (Klass**)
816 os::malloc(sizeof(Klass*) * _class_count, mtClass);
817 if (_scratch_classes == NULL) {
818 return JVMTI_ERROR_OUT_OF_MEMORY;
819 }
820 // Zero initialize the _scratch_classes array.
821 for (int i = 0; i < _class_count; i++) {
822 _scratch_classes[i] = NULL;
823 }
824
825 ResourceMark rm(THREAD);
826
827 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
828 // state can only be NULL if the current thread is exiting which
829 // should not happen since we're trying to do a RedefineClasses
830 guarantee(state != NULL, "exiting thread calling load_new_class_versions");
831 for (int i = 0; i < _class_count; i++) {
832 // Create HandleMark so that any handles created while loading new class
833 // versions are deleted. Constant pools are deallocated while merging
834 // constant pools
835 HandleMark hm(THREAD);
836
837 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass);
838 // classes for primitives cannot be redefined
839 if (!is_modifiable_class(mirror)) {
840 return JVMTI_ERROR_UNMODIFIABLE_CLASS;
841 }
842 Klass* the_class_oop = java_lang_Class::as_Klass(mirror);
843 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
844 Symbol* the_class_sym = the_class->name();
845
846 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
847 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
848 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)",
849 the_class->external_name(), _class_load_kind,
850 os::available_memory() >> 10));
851
852 ClassFileStream st((u1*) _class_defs[i].class_bytes,
853 _class_defs[i].class_byte_count, (char *)"__VM_RedefineClasses__");
854
855 // Parse the stream.
856 Handle the_class_loader(THREAD, the_class->class_loader());
857 Handle protection_domain(THREAD, the_class->protection_domain());
858 // Set redefined class handle in JvmtiThreadState class.
859 // This redefined class is sent to agent event handler for class file
860 // load hook event.
861 state->set_class_being_redefined(&the_class, _class_load_kind);
862
863 Klass* k = SystemDictionary::parse_stream(the_class_sym,
864 the_class_loader,
865 protection_domain,
866 &st,
867 THREAD);
868 // Clear class_being_redefined just to be sure.
869 state->clear_class_being_redefined();
870
871 // TODO: if this is retransform, and nothing changed we can skip it
872
873 instanceKlassHandle scratch_class (THREAD, k);
874
875 // Need to clean up allocated InstanceKlass if there's an error so assign
876 // the result here. Caller deallocates all the scratch classes in case of
877 // an error.
878 _scratch_classes[i] = k;
879
880 if (HAS_PENDING_EXCEPTION) {
881 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
882 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
883 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("parse_stream exception: '%s'",
884 ex_name->as_C_string()));
885 CLEAR_PENDING_EXCEPTION;
886
887 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) {
888 return JVMTI_ERROR_UNSUPPORTED_VERSION;
889 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) {
890 return JVMTI_ERROR_INVALID_CLASS_FORMAT;
891 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) {
892 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION;
893 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
894 // The message will be "XXX (wrong name: YYY)"
895 return JVMTI_ERROR_NAMES_DONT_MATCH;
896 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
897 return JVMTI_ERROR_OUT_OF_MEMORY;
898 } else { // Just in case more exceptions can be thrown..
899 return JVMTI_ERROR_FAILS_VERIFICATION;
900 }
901 }
902
903 // Ensure class is linked before redefine
904 if (!the_class->is_linked()) {
905 the_class->link_class(THREAD);
906 if (HAS_PENDING_EXCEPTION) {
907 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
908 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
909 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("link_class exception: '%s'",
910 ex_name->as_C_string()));
911 CLEAR_PENDING_EXCEPTION;
912 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
913 return JVMTI_ERROR_OUT_OF_MEMORY;
914 } else {
915 return JVMTI_ERROR_INTERNAL;
916 }
917 }
918 }
919
920 // Do the validity checks in compare_and_normalize_class_versions()
921 // before verifying the byte codes. By doing these checks first, we
922 // limit the number of functions that require redirection from
923 // the_class to scratch_class. In particular, we don't have to
924 // modify JNI GetSuperclass() and thus won't change its performance.
925 jvmtiError res = compare_and_normalize_class_versions(the_class,
926 scratch_class);
927 if (res != JVMTI_ERROR_NONE) {
928 return res;
929 }
930
931 // verify what the caller passed us
932 {
933 // The bug 6214132 caused the verification to fail.
934 // Information about the_class and scratch_class is temporarily
935 // recorded into jvmtiThreadState. This data is used to redirect
936 // the_class to scratch_class in the JVM_* functions called by the
937 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed
938 // description.
939 RedefineVerifyMark rvm(&the_class, &scratch_class, state);
940 Verifier::verify(
941 scratch_class, Verifier::ThrowException, true, THREAD);
942 }
943
944 if (HAS_PENDING_EXCEPTION) {
945 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
946 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
947 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
948 ("verify_byte_codes exception: '%s'", ex_name->as_C_string()));
949 CLEAR_PENDING_EXCEPTION;
950 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
951 return JVMTI_ERROR_OUT_OF_MEMORY;
952 } else {
953 // tell the caller the bytecodes are bad
954 return JVMTI_ERROR_FAILS_VERIFICATION;
955 }
956 }
957
958 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD);
959 if (res != JVMTI_ERROR_NONE) {
960 return res;
961 }
962
963 if (VerifyMergedCPBytecodes) {
964 // verify what we have done during constant pool merging
965 {
966 RedefineVerifyMark rvm(&the_class, &scratch_class, state);
967 Verifier::verify(scratch_class, Verifier::ThrowException, true, THREAD);
968 }
969
970 if (HAS_PENDING_EXCEPTION) {
971 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
972 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
973 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
974 ("verify_byte_codes post merge-CP exception: '%s'",
975 ex_name->as_C_string()));
976 CLEAR_PENDING_EXCEPTION;
977 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
978 return JVMTI_ERROR_OUT_OF_MEMORY;
979 } else {
980 // tell the caller that constant pool merging screwed up
981 return JVMTI_ERROR_INTERNAL;
982 }
983 }
984 }
985
986 Rewriter::rewrite(scratch_class, THREAD);
987 if (!HAS_PENDING_EXCEPTION) {
988 scratch_class->link_methods(THREAD);
989 }
990 if (HAS_PENDING_EXCEPTION) {
991 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
992 CLEAR_PENDING_EXCEPTION;
993 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
994 return JVMTI_ERROR_OUT_OF_MEMORY;
995 } else {
996 return JVMTI_ERROR_INTERNAL;
997 }
998 }
999
1000 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1001 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
1002 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)",
1003 the_class->external_name(), os::available_memory() >> 10));
1004 }
1005
1006 return JVMTI_ERROR_NONE;
1007 }
1008
1009
1010 // Map old_index to new_index as needed. scratch_cp is only needed
1011 // for RC_TRACE() calls.
1012 void VM_RedefineClasses::map_index(constantPoolHandle scratch_cp,
1013 int old_index, int new_index) {
1014 if (find_new_index(old_index) != 0) {
1015 // old_index is already mapped
1016 return;
1017 }
1018
1019 if (old_index == new_index) {
1020 // no mapping is needed
1021 return;
1022 }
1023
1024 _index_map_p->at_put(old_index, new_index);
1025 _index_map_count++;
1026
1027 RC_TRACE(0x00040000, ("mapped tag %d at index %d to %d",
1028 scratch_cp->tag_at(old_index).value(), old_index, new_index));
1029 } // end map_index()
1030
1031
1032 // Merge old_cp and scratch_cp and return the results of the merge via
1033 // merge_cp_p. The number of entries in *merge_cp_p is returned via
1034 // merge_cp_length_p. The entries in old_cp occupy the same locations
1035 // in *merge_cp_p. Also creates a map of indices from entries in
1036 // scratch_cp to the corresponding entry in *merge_cp_p. Index map
1037 // entries are only created for entries in scratch_cp that occupy a
1038 // different location in *merged_cp_p.
1039 bool VM_RedefineClasses::merge_constant_pools(constantPoolHandle old_cp,
1040 constantPoolHandle scratch_cp, constantPoolHandle *merge_cp_p,
1041 int *merge_cp_length_p, TRAPS) {
1042
1043 if (merge_cp_p == NULL) {
1044 assert(false, "caller must provide scratch constantPool");
1045 return false; // robustness
1046 }
1047 if (merge_cp_length_p == NULL) {
1048 assert(false, "caller must provide scratch CP length");
1049 return false; // robustness
1050 }
1051 // Worst case we need old_cp->length() + scratch_cp()->length(),
1052 // but the caller might be smart so make sure we have at least
1053 // the minimum.
1054 if ((*merge_cp_p)->length() < old_cp->length()) {
1055 assert(false, "merge area too small");
1056 return false; // robustness
1057 }
1058
1059 RC_TRACE_WITH_THREAD(0x00010000, THREAD,
1060 ("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(),
1061 scratch_cp->length()));
1062
1063 {
1064 // Pass 0:
1065 // The old_cp is copied to *merge_cp_p; this means that any code
1066 // using old_cp does not have to change. This work looks like a
1067 // perfect fit for ConstantPool*::copy_cp_to(), but we need to
1068 // handle one special case:
1069 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass
1070 // This will make verification happy.
1071
1072 int old_i; // index into old_cp
1073
1074 // index zero (0) is not used in constantPools
1075 for (old_i = 1; old_i < old_cp->length(); old_i++) {
1076 // leave debugging crumb
1077 jbyte old_tag = old_cp->tag_at(old_i).value();
1078 switch (old_tag) {
1079 case JVM_CONSTANT_Class:
1080 case JVM_CONSTANT_UnresolvedClass:
1081 // revert the copy to JVM_CONSTANT_UnresolvedClass
1082 // May be resolving while calling this so do the same for
1083 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition)
1084 (*merge_cp_p)->unresolved_klass_at_put(old_i,
1085 old_cp->klass_name_at(old_i));
1086 break;
1087
1088 case JVM_CONSTANT_Double:
1089 case JVM_CONSTANT_Long:
1090 // just copy the entry to *merge_cp_p, but double and long take
1091 // two constant pool entries
1092 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1093 old_i++;
1094 break;
1095
1096 default:
1097 // just copy the entry to *merge_cp_p
1098 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1099 break;
1100 }
1101 } // end for each old_cp entry
1102
1103 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_0);
1104
1105 // We don't need to sanity check that *merge_cp_length_p is within
1106 // *merge_cp_p bounds since we have the minimum on-entry check above.
1107 (*merge_cp_length_p) = old_i;
1108 }
1109
1110 // merge_cp_len should be the same as old_cp->length() at this point
1111 // so this trace message is really a "warm-and-breathing" message.
1112 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1113 ("after pass 0: merge_cp_len=%d", *merge_cp_length_p));
1114
1115 int scratch_i; // index into scratch_cp
1116 {
1117 // Pass 1a:
1118 // Compare scratch_cp entries to the old_cp entries that we have
1119 // already copied to *merge_cp_p. In this pass, we are eliminating
1120 // exact duplicates (matching entry at same index) so we only
1121 // compare entries in the common indice range.
1122 int increment = 1;
1123 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length());
1124 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) {
1125 switch (scratch_cp->tag_at(scratch_i).value()) {
1126 case JVM_CONSTANT_Double:
1127 case JVM_CONSTANT_Long:
1128 // double and long take two constant pool entries
1129 increment = 2;
1130 break;
1131
1132 default:
1133 increment = 1;
1134 break;
1135 }
1136
1137 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p,
1138 scratch_i, CHECK_0);
1139 if (match) {
1140 // found a match at the same index so nothing more to do
1141 continue;
1142 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i,
1143 *merge_cp_p, scratch_i)) {
1144 // The mismatch in compare_entry_to() above is because of a
1145 // resolved versus unresolved class entry at the same index
1146 // with the same string value. Since Pass 0 reverted any
1147 // class entries to unresolved class entries in *merge_cp_p,
1148 // we go with the unresolved class entry.
1149 continue;
1150 }
1151
1152 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p,
1153 CHECK_0);
1154 if (found_i != 0) {
1155 guarantee(found_i != scratch_i,
1156 "compare_entry_to() and find_matching_entry() do not agree");
1157
1158 // Found a matching entry somewhere else in *merge_cp_p so
1159 // just need a mapping entry.
1160 map_index(scratch_cp, scratch_i, found_i);
1161 continue;
1162 }
1163
1164 // The find_matching_entry() call above could fail to find a match
1165 // due to a resolved versus unresolved class or string entry situation
1166 // like we solved above with the is_unresolved_*_mismatch() calls.
1167 // However, we would have to call is_unresolved_*_mismatch() over
1168 // all of *merge_cp_p (potentially) and that doesn't seem to be
1169 // worth the time.
1170
1171 // No match found so we have to append this entry and any unique
1172 // referenced entries to *merge_cp_p.
1173 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1174 CHECK_0);
1175 }
1176 }
1177
1178 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1179 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1180 *merge_cp_length_p, scratch_i, _index_map_count));
1181
1182 if (scratch_i < scratch_cp->length()) {
1183 // Pass 1b:
1184 // old_cp is smaller than scratch_cp so there are entries in
1185 // scratch_cp that we have not yet processed. We take care of
1186 // those now.
1187 int increment = 1;
1188 for (; scratch_i < scratch_cp->length(); scratch_i += increment) {
1189 switch (scratch_cp->tag_at(scratch_i).value()) {
1190 case JVM_CONSTANT_Double:
1191 case JVM_CONSTANT_Long:
1192 // double and long take two constant pool entries
1193 increment = 2;
1194 break;
1195
1196 default:
1197 increment = 1;
1198 break;
1199 }
1200
1201 int found_i =
1202 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0);
1203 if (found_i != 0) {
1204 // Found a matching entry somewhere else in *merge_cp_p so
1205 // just need a mapping entry.
1206 map_index(scratch_cp, scratch_i, found_i);
1207 continue;
1208 }
1209
1210 // No match found so we have to append this entry and any unique
1211 // referenced entries to *merge_cp_p.
1212 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1213 CHECK_0);
1214 }
1215
1216 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1217 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1218 *merge_cp_length_p, scratch_i, _index_map_count));
1219 }
1220
1221 return true;
1222 } // end merge_constant_pools()
1223
1224
1225 // Scoped object to clean up the constant pool(s) created for merging
1226 class MergeCPCleaner {
1227 ClassLoaderData* _loader_data;
1228 ConstantPool* _cp;
1229 ConstantPool* _scratch_cp;
1230 public:
1231 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) :
1232 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {}
1233 ~MergeCPCleaner() {
1234 _loader_data->add_to_deallocate_list(_cp);
1235 if (_scratch_cp != NULL) {
1236 _loader_data->add_to_deallocate_list(_scratch_cp);
1237 }
1238 }
1239 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; }
1240 };
1241
1242 // Merge constant pools between the_class and scratch_class and
1243 // potentially rewrite bytecodes in scratch_class to use the merged
1244 // constant pool.
1245 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite(
1246 instanceKlassHandle the_class, instanceKlassHandle scratch_class,
1247 TRAPS) {
1248 // worst case merged constant pool length is old and new combined
1249 int merge_cp_length = the_class->constants()->length()
1250 + scratch_class->constants()->length();
1251
1252 // Constant pools are not easily reused so we allocate a new one
1253 // each time.
1254 // merge_cp is created unsafe for concurrent GC processing. It
1255 // should be marked safe before discarding it. Even though
1256 // garbage, if it crosses a card boundary, it may be scanned
1257 // in order to find the start of the first complete object on the card.
1258 ClassLoaderData* loader_data = the_class->class_loader_data();
1259 ConstantPool* merge_cp_oop =
1260 ConstantPool::allocate(loader_data,
1261 merge_cp_length,
1262 THREAD);
1263 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop);
1264
1265 HandleMark hm(THREAD); // make sure handles are cleared before
1266 // MergeCPCleaner clears out merge_cp_oop
1267 constantPoolHandle merge_cp(THREAD, merge_cp_oop);
1268
1269 // Get constants() from the old class because it could have been rewritten
1270 // while we were at a safepoint allocating a new constant pool.
1271 constantPoolHandle old_cp(THREAD, the_class->constants());
1272 constantPoolHandle scratch_cp(THREAD, scratch_class->constants());
1273
1274 // If the length changed, the class was redefined out from under us. Return
1275 // an error.
1276 if (merge_cp_length != the_class->constants()->length()
1277 + scratch_class->constants()->length()) {
1278 return JVMTI_ERROR_INTERNAL;
1279 }
1280
1281 // Update the version number of the constant pool
1282 merge_cp->increment_and_save_version(old_cp->version());
1283
1284 ResourceMark rm(THREAD);
1285 _index_map_count = 0;
1286 _index_map_p = new intArray(scratch_cp->length(), -1);
1287
1288 // reference to the cp holder is needed for copy_operands()
1289 merge_cp->set_pool_holder(scratch_class());
1290 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp,
1291 &merge_cp_length, THREAD);
1292 merge_cp->set_pool_holder(NULL);
1293
1294 if (!result) {
1295 // The merge can fail due to memory allocation failure or due
1296 // to robustness checks.
1297 return JVMTI_ERROR_INTERNAL;
1298 }
1299
1300 RC_TRACE_WITH_THREAD(0x00010000, THREAD,
1301 ("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count));
1302
1303 if (_index_map_count == 0) {
1304 // there is nothing to map between the new and merged constant pools
1305
1306 if (old_cp->length() == scratch_cp->length()) {
1307 // The old and new constant pools are the same length and the
1308 // index map is empty. This means that the three constant pools
1309 // are equivalent (but not the same). Unfortunately, the new
1310 // constant pool has not gone through link resolution nor have
1311 // the new class bytecodes gone through constant pool cache
1312 // rewriting so we can't use the old constant pool with the new
1313 // class.
1314
1315 // toss the merged constant pool at return
1316 } else if (old_cp->length() < scratch_cp->length()) {
1317 // The old constant pool has fewer entries than the new constant
1318 // pool and the index map is empty. This means the new constant
1319 // pool is a superset of the old constant pool. However, the old
1320 // class bytecodes have already gone through constant pool cache
1321 // rewriting so we can't use the new constant pool with the old
1322 // class.
1323
1324 // toss the merged constant pool at return
1325 } else {
1326 // The old constant pool has more entries than the new constant
1327 // pool and the index map is empty. This means that both the old
1328 // and merged constant pools are supersets of the new constant
1329 // pool.
1330
1331 // Replace the new constant pool with a shrunken copy of the
1332 // merged constant pool
1333 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, THREAD);
1334 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1335 // It can't be cleaned up while there are handles to it.
1336 cp_cleaner.add_scratch_cp(scratch_cp());
1337 }
1338 } else {
1339 if (RC_TRACE_ENABLED(0x00040000)) {
1340 // don't want to loop unless we are tracing
1341 int count = 0;
1342 for (int i = 1; i < _index_map_p->length(); i++) {
1343 int value = _index_map_p->at(i);
1344
1345 if (value != -1) {
1346 RC_TRACE_WITH_THREAD(0x00040000, THREAD,
1347 ("index_map[%d]: old=%d new=%d", count, i, value));
1348 count++;
1349 }
1350 }
1351 }
1352
1353 // We have entries mapped between the new and merged constant pools
1354 // so we have to rewrite some constant pool references.
1355 if (!rewrite_cp_refs(scratch_class, THREAD)) {
1356 return JVMTI_ERROR_INTERNAL;
1357 }
1358
1359 // Replace the new constant pool with a shrunken copy of the
1360 // merged constant pool so now the rewritten bytecodes have
1361 // valid references; the previous new constant pool will get
1362 // GCed.
1363 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, THREAD);
1364 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1365 // It can't be cleaned up while there are handles to it.
1366 cp_cleaner.add_scratch_cp(scratch_cp());
1367 }
1368
1369 return JVMTI_ERROR_NONE;
1370 } // end merge_cp_and_rewrite()
1371
1372
1373 // Rewrite constant pool references in klass scratch_class.
1374 bool VM_RedefineClasses::rewrite_cp_refs(instanceKlassHandle scratch_class,
1375 TRAPS) {
1376
1377 // rewrite constant pool references in the methods:
1378 if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) {
1379 // propagate failure back to caller
1380 return false;
1381 }
1382
1383 // rewrite constant pool references in the class_annotations:
1384 if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) {
1385 // propagate failure back to caller
1386 return false;
1387 }
1388
1389 // rewrite constant pool references in the fields_annotations:
1390 if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) {
1391 // propagate failure back to caller
1392 return false;
1393 }
1394
1395 // rewrite constant pool references in the methods_annotations:
1396 if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) {
1397 // propagate failure back to caller
1398 return false;
1399 }
1400
1401 // rewrite constant pool references in the methods_parameter_annotations:
1402 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class,
1403 THREAD)) {
1404 // propagate failure back to caller
1405 return false;
1406 }
1407
1408 // rewrite constant pool references in the methods_default_annotations:
1409 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class,
1410 THREAD)) {
1411 // propagate failure back to caller
1412 return false;
1413 }
1414
1415 return true;
1416 } // end rewrite_cp_refs()
1417
1418
1419 // Rewrite constant pool references in the methods.
1420 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(
1421 instanceKlassHandle scratch_class, TRAPS) {
1422
1423 Array<Method*>* methods = scratch_class->methods();
1424
1425 if (methods == NULL || methods->length() == 0) {
1426 // no methods so nothing to do
1427 return true;
1428 }
1429
1430 // rewrite constant pool references in the methods:
1431 for (int i = methods->length() - 1; i >= 0; i--) {
1432 methodHandle method(THREAD, methods->at(i));
1433 methodHandle new_method;
1434 rewrite_cp_refs_in_method(method, &new_method, CHECK_false);
1435 if (!new_method.is_null()) {
1436 // the method has been replaced so save the new method version
1437 methods->at_put(i, new_method());
1438 }
1439 }
1440
1441 return true;
1442 }
1443
1444
1445 // Rewrite constant pool references in the specific method. This code
1446 // was adapted from Rewriter::rewrite_method().
1447 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method,
1448 methodHandle *new_method_p, TRAPS) {
1449
1450 *new_method_p = methodHandle(); // default is no new method
1451
1452 // We cache a pointer to the bytecodes here in code_base. If GC
1453 // moves the Method*, then the bytecodes will also move which
1454 // will likely cause a crash. We create a No_Safepoint_Verifier
1455 // object to detect whether we pass a possible safepoint in this
1456 // code block.
1457 No_Safepoint_Verifier nsv;
1458
1459 // Bytecodes and their length
1460 address code_base = method->code_base();
1461 int code_length = method->code_size();
1462
1463 int bc_length;
1464 for (int bci = 0; bci < code_length; bci += bc_length) {
1465 address bcp = code_base + bci;
1466 Bytecodes::Code c = (Bytecodes::Code)(*bcp);
1467
1468 bc_length = Bytecodes::length_for(c);
1469 if (bc_length == 0) {
1470 // More complicated bytecodes report a length of zero so
1471 // we have to try again a slightly different way.
1472 bc_length = Bytecodes::length_at(method(), bcp);
1473 }
1474
1475 assert(bc_length != 0, "impossible bytecode length");
1476
1477 switch (c) {
1478 case Bytecodes::_ldc:
1479 {
1480 int cp_index = *(bcp + 1);
1481 int new_index = find_new_index(cp_index);
1482
1483 if (StressLdcRewrite && new_index == 0) {
1484 // If we are stressing ldc -> ldc_w rewriting, then we
1485 // always need a new_index value.
1486 new_index = cp_index;
1487 }
1488 if (new_index != 0) {
1489 // the original index is mapped so we have more work to do
1490 if (!StressLdcRewrite && new_index <= max_jubyte) {
1491 // The new value can still use ldc instead of ldc_w
1492 // unless we are trying to stress ldc -> ldc_w rewriting
1493 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1494 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
1495 bcp, cp_index, new_index));
1496 *(bcp + 1) = new_index;
1497 } else {
1498 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1499 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d",
1500 Bytecodes::name(c), bcp, cp_index, new_index));
1501 // the new value needs ldc_w instead of ldc
1502 u_char inst_buffer[4]; // max instruction size is 4 bytes
1503 bcp = (address)inst_buffer;
1504 // construct new instruction sequence
1505 *bcp = Bytecodes::_ldc_w;
1506 bcp++;
1507 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w.
1508 // See comment below for difference between put_Java_u2()
1509 // and put_native_u2().
1510 Bytes::put_Java_u2(bcp, new_index);
1511
1512 Relocator rc(method, NULL /* no RelocatorListener needed */);
1513 methodHandle m;
1514 {
1515 Pause_No_Safepoint_Verifier pnsv(&nsv);
1516
1517 // ldc is 2 bytes and ldc_w is 3 bytes
1518 m = rc.insert_space_at(bci, 3, inst_buffer, THREAD);
1519 if (m.is_null() || HAS_PENDING_EXCEPTION) {
1520 guarantee(false, "insert_space_at() failed");
1521 }
1522 }
1523
1524 // return the new method so that the caller can update
1525 // the containing class
1526 *new_method_p = method = m;
1527 // switch our bytecode processing loop from the old method
1528 // to the new method
1529 code_base = method->code_base();
1530 code_length = method->code_size();
1531 bcp = code_base + bci;
1532 c = (Bytecodes::Code)(*bcp);
1533 bc_length = Bytecodes::length_for(c);
1534 assert(bc_length != 0, "sanity check");
1535 } // end we need ldc_w instead of ldc
1536 } // end if there is a mapped index
1537 } break;
1538
1539 // these bytecodes have a two-byte constant pool index
1540 case Bytecodes::_anewarray : // fall through
1541 case Bytecodes::_checkcast : // fall through
1542 case Bytecodes::_getfield : // fall through
1543 case Bytecodes::_getstatic : // fall through
1544 case Bytecodes::_instanceof : // fall through
1545 case Bytecodes::_invokedynamic : // fall through
1546 case Bytecodes::_invokeinterface: // fall through
1547 case Bytecodes::_invokespecial : // fall through
1548 case Bytecodes::_invokestatic : // fall through
1549 case Bytecodes::_invokevirtual : // fall through
1550 case Bytecodes::_ldc_w : // fall through
1551 case Bytecodes::_ldc2_w : // fall through
1552 case Bytecodes::_multianewarray : // fall through
1553 case Bytecodes::_new : // fall through
1554 case Bytecodes::_putfield : // fall through
1555 case Bytecodes::_putstatic :
1556 {
1557 address p = bcp + 1;
1558 int cp_index = Bytes::get_Java_u2(p);
1559 int new_index = find_new_index(cp_index);
1560 if (new_index != 0) {
1561 // the original index is mapped so update w/ new value
1562 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1563 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
1564 bcp, cp_index, new_index));
1565 // Rewriter::rewrite_method() uses put_native_u2() in this
1566 // situation because it is reusing the constant pool index
1567 // location for a native index into the constantPoolCache.
1568 // Since we are updating the constant pool index prior to
1569 // verification and constantPoolCache initialization, we
1570 // need to keep the new index in Java byte order.
1571 Bytes::put_Java_u2(p, new_index);
1572 }
1573 } break;
1574 }
1575 } // end for each bytecode
1576 } // end rewrite_cp_refs_in_method()
1577
1578
1579 // Rewrite constant pool references in the class_annotations field.
1580 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(
1581 instanceKlassHandle scratch_class, TRAPS) {
1582
1583 AnnotationArray* class_annotations = scratch_class->class_annotations();
1584 if (class_annotations == NULL || class_annotations->length() == 0) {
1585 // no class_annotations so nothing to do
1586 return true;
1587 }
1588
1589 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1590 ("class_annotations length=%d", class_annotations->length()));
1591
1592 int byte_i = 0; // byte index into class_annotations
1593 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i,
1594 THREAD);
1595 }
1596
1597
1598 // Rewrite constant pool references in an annotations typeArray. This
1599 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute
1600 // that is described in section 4.8.15 of the 2nd-edition of the VM spec:
1601 //
1602 // annotations_typeArray {
1603 // u2 num_annotations;
1604 // annotation annotations[num_annotations];
1605 // }
1606 //
1607 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray(
1608 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1609
1610 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1611 // not enough room for num_annotations field
1612 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1613 ("length() is too small for num_annotations field"));
1614 return false;
1615 }
1616
1617 u2 num_annotations = Bytes::get_Java_u2((address)
1618 annotations_typeArray->adr_at(byte_i_ref));
1619 byte_i_ref += 2;
1620
1621 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1622 ("num_annotations=%d", num_annotations));
1623
1624 int calc_num_annotations = 0;
1625 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
1626 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
1627 byte_i_ref, THREAD)) {
1628 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1629 ("bad annotation_struct at %d", calc_num_annotations));
1630 // propagate failure back to caller
1631 return false;
1632 }
1633 }
1634 assert(num_annotations == calc_num_annotations, "sanity check");
1635
1636 return true;
1637 } // end rewrite_cp_refs_in_annotations_typeArray()
1638
1639
1640 // Rewrite constant pool references in the annotation struct portion of
1641 // an annotations_typeArray. This "structure" is from section 4.8.15 of
1642 // the 2nd-edition of the VM spec:
1643 //
1644 // struct annotation {
1645 // u2 type_index;
1646 // u2 num_element_value_pairs;
1647 // {
1648 // u2 element_name_index;
1649 // element_value value;
1650 // } element_value_pairs[num_element_value_pairs];
1651 // }
1652 //
1653 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct(
1654 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1655 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) {
1656 // not enough room for smallest annotation_struct
1657 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1658 ("length() is too small for annotation_struct"));
1659 return false;
1660 }
1661
1662 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray,
1663 byte_i_ref, "mapped old type_index=%d", THREAD);
1664
1665 u2 num_element_value_pairs = Bytes::get_Java_u2((address)
1666 annotations_typeArray->adr_at(byte_i_ref));
1667 byte_i_ref += 2;
1668
1669 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1670 ("type_index=%d num_element_value_pairs=%d", type_index,
1671 num_element_value_pairs));
1672
1673 int calc_num_element_value_pairs = 0;
1674 for (; calc_num_element_value_pairs < num_element_value_pairs;
1675 calc_num_element_value_pairs++) {
1676 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1677 // not enough room for another element_name_index, let alone
1678 // the rest of another component
1679 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1680 ("length() is too small for element_name_index"));
1681 return false;
1682 }
1683
1684 u2 element_name_index = rewrite_cp_ref_in_annotation_data(
1685 annotations_typeArray, byte_i_ref,
1686 "mapped old element_name_index=%d", THREAD);
1687
1688 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1689 ("element_name_index=%d", element_name_index));
1690
1691 if (!rewrite_cp_refs_in_element_value(annotations_typeArray,
1692 byte_i_ref, THREAD)) {
1693 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1694 ("bad element_value at %d", calc_num_element_value_pairs));
1695 // propagate failure back to caller
1696 return false;
1697 }
1698 } // end for each component
1699 assert(num_element_value_pairs == calc_num_element_value_pairs,
1700 "sanity check");
1701
1702 return true;
1703 } // end rewrite_cp_refs_in_annotation_struct()
1704
1705
1706 // Rewrite a constant pool reference at the current position in
1707 // annotations_typeArray if needed. Returns the original constant
1708 // pool reference if a rewrite was not needed or the new constant
1709 // pool reference if a rewrite was needed.
1710 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data(
1711 AnnotationArray* annotations_typeArray, int &byte_i_ref,
1712 const char * trace_mesg, TRAPS) {
1713
1714 address cp_index_addr = (address)
1715 annotations_typeArray->adr_at(byte_i_ref);
1716 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr);
1717 u2 new_cp_index = find_new_index(old_cp_index);
1718 if (new_cp_index != 0) {
1719 RC_TRACE_WITH_THREAD(0x02000000, THREAD, (trace_mesg, old_cp_index));
1720 Bytes::put_Java_u2(cp_index_addr, new_cp_index);
1721 old_cp_index = new_cp_index;
1722 }
1723 byte_i_ref += 2;
1724 return old_cp_index;
1725 }
1726
1727
1728 // Rewrite constant pool references in the element_value portion of an
1729 // annotations_typeArray. This "structure" is from section 4.8.15.1 of
1730 // the 2nd-edition of the VM spec:
1731 //
1732 // struct element_value {
1733 // u1 tag;
1734 // union {
1735 // u2 const_value_index;
1736 // {
1737 // u2 type_name_index;
1738 // u2 const_name_index;
1739 // } enum_const_value;
1740 // u2 class_info_index;
1741 // annotation annotation_value;
1742 // struct {
1743 // u2 num_values;
1744 // element_value values[num_values];
1745 // } array_value;
1746 // } value;
1747 // }
1748 //
1749 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value(
1750 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1751
1752 if ((byte_i_ref + 1) > annotations_typeArray->length()) {
1753 // not enough room for a tag let alone the rest of an element_value
1754 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1755 ("length() is too small for a tag"));
1756 return false;
1757 }
1758
1759 u1 tag = annotations_typeArray->at(byte_i_ref);
1760 byte_i_ref++;
1761 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("tag='%c'", tag));
1762
1763 switch (tag) {
1764 // These BaseType tag values are from Table 4.2 in VM spec:
1765 case 'B': // byte
1766 case 'C': // char
1767 case 'D': // double
1768 case 'F': // float
1769 case 'I': // int
1770 case 'J': // long
1771 case 'S': // short
1772 case 'Z': // boolean
1773
1774 // The remaining tag values are from Table 4.8 in the 2nd-edition of
1775 // the VM spec:
1776 case 's':
1777 {
1778 // For the above tag values (including the BaseType values),
1779 // value.const_value_index is right union field.
1780
1781 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1782 // not enough room for a const_value_index
1783 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1784 ("length() is too small for a const_value_index"));
1785 return false;
1786 }
1787
1788 u2 const_value_index = rewrite_cp_ref_in_annotation_data(
1789 annotations_typeArray, byte_i_ref,
1790 "mapped old const_value_index=%d", THREAD);
1791
1792 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1793 ("const_value_index=%d", const_value_index));
1794 } break;
1795
1796 case 'e':
1797 {
1798 // for the above tag value, value.enum_const_value is right union field
1799
1800 if ((byte_i_ref + 4) > annotations_typeArray->length()) {
1801 // not enough room for a enum_const_value
1802 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1803 ("length() is too small for a enum_const_value"));
1804 return false;
1805 }
1806
1807 u2 type_name_index = rewrite_cp_ref_in_annotation_data(
1808 annotations_typeArray, byte_i_ref,
1809 "mapped old type_name_index=%d", THREAD);
1810
1811 u2 const_name_index = rewrite_cp_ref_in_annotation_data(
1812 annotations_typeArray, byte_i_ref,
1813 "mapped old const_name_index=%d", THREAD);
1814
1815 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1816 ("type_name_index=%d const_name_index=%d", type_name_index,
1817 const_name_index));
1818 } break;
1819
1820 case 'c':
1821 {
1822 // for the above tag value, value.class_info_index is right union field
1823
1824 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1825 // not enough room for a class_info_index
1826 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1827 ("length() is too small for a class_info_index"));
1828 return false;
1829 }
1830
1831 u2 class_info_index = rewrite_cp_ref_in_annotation_data(
1832 annotations_typeArray, byte_i_ref,
1833 "mapped old class_info_index=%d", THREAD);
1834
1835 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1836 ("class_info_index=%d", class_info_index));
1837 } break;
1838
1839 case '@':
1840 // For the above tag value, value.attr_value is the right union
1841 // field. This is a nested annotation.
1842 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
1843 byte_i_ref, THREAD)) {
1844 // propagate failure back to caller
1845 return false;
1846 }
1847 break;
1848
1849 case '[':
1850 {
1851 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1852 // not enough room for a num_values field
1853 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1854 ("length() is too small for a num_values field"));
1855 return false;
1856 }
1857
1858 // For the above tag value, value.array_value is the right union
1859 // field. This is an array of nested element_value.
1860 u2 num_values = Bytes::get_Java_u2((address)
1861 annotations_typeArray->adr_at(byte_i_ref));
1862 byte_i_ref += 2;
1863 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("num_values=%d", num_values));
1864
1865 int calc_num_values = 0;
1866 for (; calc_num_values < num_values; calc_num_values++) {
1867 if (!rewrite_cp_refs_in_element_value(
1868 annotations_typeArray, byte_i_ref, THREAD)) {
1869 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1870 ("bad nested element_value at %d", calc_num_values));
1871 // propagate failure back to caller
1872 return false;
1873 }
1874 }
1875 assert(num_values == calc_num_values, "sanity check");
1876 } break;
1877
1878 default:
1879 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("bad tag=0x%x", tag));
1880 return false;
1881 } // end decode tag field
1882
1883 return true;
1884 } // end rewrite_cp_refs_in_element_value()
1885
1886
1887 // Rewrite constant pool references in a fields_annotations field.
1888 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations(
1889 instanceKlassHandle scratch_class, TRAPS) {
1890
1891 Annotations* sca = scratch_class->annotations();
1892 if (sca == NULL) return true;
1893
1894 Array<AnnotationArray*>* fields_annotations = sca->fields_annotations();
1895
1896 if (fields_annotations == NULL || fields_annotations->length() == 0) {
1897 // no fields_annotations so nothing to do
1898 return true;
1899 }
1900
1901 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1902 ("fields_annotations length=%d", fields_annotations->length()));
1903
1904 for (int i = 0; i < fields_annotations->length(); i++) {
1905 AnnotationArray* field_annotations = fields_annotations->at(i);
1906 if (field_annotations == NULL || field_annotations->length() == 0) {
1907 // this field does not have any annotations so skip it
1908 continue;
1909 }
1910
1911 int byte_i = 0; // byte index into field_annotations
1912 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i,
1913 THREAD)) {
1914 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1915 ("bad field_annotations at %d", i));
1916 // propagate failure back to caller
1917 return false;
1918 }
1919 }
1920
1921 return true;
1922 } // end rewrite_cp_refs_in_fields_annotations()
1923
1924
1925 // Rewrite constant pool references in a methods_annotations field.
1926 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations(
1927 instanceKlassHandle scratch_class, TRAPS) {
1928
1929 Annotations* sca = scratch_class->annotations();
1930 if (sca == NULL) return true;
1931
1932 Array<AnnotationArray*>* methods_annotations = sca->methods_annotations();
1933
1934 if (methods_annotations == NULL || methods_annotations->length() == 0) {
1935 // no methods_annotations so nothing to do
1936 return true;
1937 }
1938
1939 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1940 ("methods_annotations length=%d", methods_annotations->length()));
1941
1942 for (int i = 0; i < methods_annotations->length(); i++) {
1943 AnnotationArray* method_annotations = methods_annotations->at(i);
1944 if (method_annotations == NULL || method_annotations->length() == 0) {
1945 // this method does not have any annotations so skip it
1946 continue;
1947 }
1948
1949 int byte_i = 0; // byte index into method_annotations
1950 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i,
1951 THREAD)) {
1952 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1953 ("bad method_annotations at %d", i));
1954 // propagate failure back to caller
1955 return false;
1956 }
1957 }
1958
1959 return true;
1960 } // end rewrite_cp_refs_in_methods_annotations()
1961
1962
1963 // Rewrite constant pool references in a methods_parameter_annotations
1964 // field. This "structure" is adapted from the
1965 // RuntimeVisibleParameterAnnotations_attribute described in section
1966 // 4.8.17 of the 2nd-edition of the VM spec:
1967 //
1968 // methods_parameter_annotations_typeArray {
1969 // u1 num_parameters;
1970 // {
1971 // u2 num_annotations;
1972 // annotation annotations[num_annotations];
1973 // } parameter_annotations[num_parameters];
1974 // }
1975 //
1976 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations(
1977 instanceKlassHandle scratch_class, TRAPS) {
1978
1979 Annotations* sca = scratch_class->annotations();
1980 if (sca == NULL) return true;
1981
1982 Array<AnnotationArray*>* methods_parameter_annotations =
1983 sca->methods_parameter_annotations();
1984
1985 if (methods_parameter_annotations == NULL
1986 || methods_parameter_annotations->length() == 0) {
1987 // no methods_parameter_annotations so nothing to do
1988 return true;
1989 }
1990
1991 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1992 ("methods_parameter_annotations length=%d",
1993 methods_parameter_annotations->length()));
1994
1995 for (int i = 0; i < methods_parameter_annotations->length(); i++) {
1996 AnnotationArray* method_parameter_annotations = methods_parameter_annotations->at(i);
1997 if (method_parameter_annotations == NULL
1998 || method_parameter_annotations->length() == 0) {
1999 // this method does not have any parameter annotations so skip it
2000 continue;
2001 }
2002
2003 if (method_parameter_annotations->length() < 1) {
2004 // not enough room for a num_parameters field
2005 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2006 ("length() is too small for a num_parameters field at %d", i));
2007 return false;
2008 }
2009
2010 int byte_i = 0; // byte index into method_parameter_annotations
2011
2012 u1 num_parameters = method_parameter_annotations->at(byte_i);
2013 byte_i++;
2014
2015 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2016 ("num_parameters=%d", num_parameters));
2017
2018 int calc_num_parameters = 0;
2019 for (; calc_num_parameters < num_parameters; calc_num_parameters++) {
2020 if (!rewrite_cp_refs_in_annotations_typeArray(
2021 method_parameter_annotations, byte_i, THREAD)) {
2022 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2023 ("bad method_parameter_annotations at %d", calc_num_parameters));
2024 // propagate failure back to caller
2025 return false;
2026 }
2027 }
2028 assert(num_parameters == calc_num_parameters, "sanity check");
2029 }
2030
2031 return true;
2032 } // end rewrite_cp_refs_in_methods_parameter_annotations()
2033
2034
2035 // Rewrite constant pool references in a methods_default_annotations
2036 // field. This "structure" is adapted from the AnnotationDefault_attribute
2037 // that is described in section 4.8.19 of the 2nd-edition of the VM spec:
2038 //
2039 // methods_default_annotations_typeArray {
2040 // element_value default_value;
2041 // }
2042 //
2043 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations(
2044 instanceKlassHandle scratch_class, TRAPS) {
2045
2046 Annotations* sca = scratch_class->annotations();
2047 if (sca == NULL) return true;
2048
2049 Array<AnnotationArray*>* methods_default_annotations =
2050 sca->methods_default_annotations();
2051
2052 if (methods_default_annotations == NULL
2053 || methods_default_annotations->length() == 0) {
2054 // no methods_default_annotations so nothing to do
2055 return true;
2056 }
2057
2058 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2059 ("methods_default_annotations length=%d",
2060 methods_default_annotations->length()));
2061
2062 for (int i = 0; i < methods_default_annotations->length(); i++) {
2063 AnnotationArray* method_default_annotations = methods_default_annotations->at(i);
2064 if (method_default_annotations == NULL
2065 || method_default_annotations->length() == 0) {
2066 // this method does not have any default annotations so skip it
2067 continue;
2068 }
2069
2070 int byte_i = 0; // byte index into method_default_annotations
2071
2072 if (!rewrite_cp_refs_in_element_value(
2073 method_default_annotations, byte_i, THREAD)) {
2074 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2075 ("bad default element_value at %d", i));
2076 // propagate failure back to caller
2077 return false;
2078 }
2079 }
2080
2081 return true;
2082 } // end rewrite_cp_refs_in_methods_default_annotations()
2083
2084
2085 // Rewrite constant pool references in the method's stackmap table.
2086 // These "structures" are adapted from the StackMapTable_attribute that
2087 // is described in section 4.8.4 of the 6.0 version of the VM spec
2088 // (dated 2005.10.26):
2089 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2090 //
2091 // stack_map {
2092 // u2 number_of_entries;
2093 // stack_map_frame entries[number_of_entries];
2094 // }
2095 //
2096 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table(
2097 methodHandle method, TRAPS) {
2098
2099 if (!method->has_stackmap_table()) {
2100 return;
2101 }
2102
2103 AnnotationArray* stackmap_data = method->stackmap_data();
2104 address stackmap_p = (address)stackmap_data->adr_at(0);
2105 address stackmap_end = stackmap_p + stackmap_data->length();
2106
2107 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries");
2108 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p);
2109 stackmap_p += 2;
2110
2111 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2112 ("number_of_entries=%u", number_of_entries));
2113
2114 // walk through each stack_map_frame
2115 u2 calc_number_of_entries = 0;
2116 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) {
2117 // The stack_map_frame structure is a u1 frame_type followed by
2118 // 0 or more bytes of data:
2119 //
2120 // union stack_map_frame {
2121 // same_frame;
2122 // same_locals_1_stack_item_frame;
2123 // same_locals_1_stack_item_frame_extended;
2124 // chop_frame;
2125 // same_frame_extended;
2126 // append_frame;
2127 // full_frame;
2128 // }
2129
2130 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type");
2131 // The Linux compiler does not like frame_type to be u1 or u2. It
2132 // issues the following warning for the first if-statement below:
2133 //
2134 // "warning: comparison is always true due to limited range of data type"
2135 //
2136 u4 frame_type = *stackmap_p;
2137 stackmap_p++;
2138
2139 // same_frame {
2140 // u1 frame_type = SAME; /* 0-63 */
2141 // }
2142 if (frame_type >= 0 && frame_type <= 63) {
2143 // nothing more to do for same_frame
2144 }
2145
2146 // same_locals_1_stack_item_frame {
2147 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */
2148 // verification_type_info stack[1];
2149 // }
2150 else if (frame_type >= 64 && frame_type <= 127) {
2151 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2152 calc_number_of_entries, frame_type, THREAD);
2153 }
2154
2155 // reserved for future use
2156 else if (frame_type >= 128 && frame_type <= 246) {
2157 // nothing more to do for reserved frame_types
2158 }
2159
2160 // same_locals_1_stack_item_frame_extended {
2161 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */
2162 // u2 offset_delta;
2163 // verification_type_info stack[1];
2164 // }
2165 else if (frame_type == 247) {
2166 stackmap_p += 2;
2167 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2168 calc_number_of_entries, frame_type, THREAD);
2169 }
2170
2171 // chop_frame {
2172 // u1 frame_type = CHOP; /* 248-250 */
2173 // u2 offset_delta;
2174 // }
2175 else if (frame_type >= 248 && frame_type <= 250) {
2176 stackmap_p += 2;
2177 }
2178
2179 // same_frame_extended {
2180 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/
2181 // u2 offset_delta;
2182 // }
2183 else if (frame_type == 251) {
2184 stackmap_p += 2;
2185 }
2186
2187 // append_frame {
2188 // u1 frame_type = APPEND; /* 252-254 */
2189 // u2 offset_delta;
2190 // verification_type_info locals[frame_type - 251];
2191 // }
2192 else if (frame_type >= 252 && frame_type <= 254) {
2193 assert(stackmap_p + 2 <= stackmap_end,
2194 "no room for offset_delta");
2195 stackmap_p += 2;
2196 u1 len = frame_type - 251;
2197 for (u1 i = 0; i < len; i++) {
2198 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2199 calc_number_of_entries, frame_type, THREAD);
2200 }
2201 }
2202
2203 // full_frame {
2204 // u1 frame_type = FULL_FRAME; /* 255 */
2205 // u2 offset_delta;
2206 // u2 number_of_locals;
2207 // verification_type_info locals[number_of_locals];
2208 // u2 number_of_stack_items;
2209 // verification_type_info stack[number_of_stack_items];
2210 // }
2211 else if (frame_type == 255) {
2212 assert(stackmap_p + 2 + 2 <= stackmap_end,
2213 "no room for smallest full_frame");
2214 stackmap_p += 2;
2215
2216 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p);
2217 stackmap_p += 2;
2218
2219 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) {
2220 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2221 calc_number_of_entries, frame_type, THREAD);
2222 }
2223
2224 // Use the largest size for the number_of_stack_items, but only get
2225 // the right number of bytes.
2226 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p);
2227 stackmap_p += 2;
2228
2229 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) {
2230 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2231 calc_number_of_entries, frame_type, THREAD);
2232 }
2233 }
2234 } // end while there is a stack_map_frame
2235 assert(number_of_entries == calc_number_of_entries, "sanity check");
2236 } // end rewrite_cp_refs_in_stack_map_table()
2237
2238
2239 // Rewrite constant pool references in the verification type info
2240 // portion of the method's stackmap table. These "structures" are
2241 // adapted from the StackMapTable_attribute that is described in
2242 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26):
2243 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2244 //
2245 // The verification_type_info structure is a u1 tag followed by 0 or
2246 // more bytes of data:
2247 //
2248 // union verification_type_info {
2249 // Top_variable_info;
2250 // Integer_variable_info;
2251 // Float_variable_info;
2252 // Long_variable_info;
2253 // Double_variable_info;
2254 // Null_variable_info;
2255 // UninitializedThis_variable_info;
2256 // Object_variable_info;
2257 // Uninitialized_variable_info;
2258 // }
2259 //
2260 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info(
2261 address& stackmap_p_ref, address stackmap_end, u2 frame_i,
2262 u1 frame_type, TRAPS) {
2263
2264 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag");
2265 u1 tag = *stackmap_p_ref;
2266 stackmap_p_ref++;
2267
2268 switch (tag) {
2269 // Top_variable_info {
2270 // u1 tag = ITEM_Top; /* 0 */
2271 // }
2272 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top
2273 case 0: // fall through
2274
2275 // Integer_variable_info {
2276 // u1 tag = ITEM_Integer; /* 1 */
2277 // }
2278 case ITEM_Integer: // fall through
2279
2280 // Float_variable_info {
2281 // u1 tag = ITEM_Float; /* 2 */
2282 // }
2283 case ITEM_Float: // fall through
2284
2285 // Double_variable_info {
2286 // u1 tag = ITEM_Double; /* 3 */
2287 // }
2288 case ITEM_Double: // fall through
2289
2290 // Long_variable_info {
2291 // u1 tag = ITEM_Long; /* 4 */
2292 // }
2293 case ITEM_Long: // fall through
2294
2295 // Null_variable_info {
2296 // u1 tag = ITEM_Null; /* 5 */
2297 // }
2298 case ITEM_Null: // fall through
2299
2300 // UninitializedThis_variable_info {
2301 // u1 tag = ITEM_UninitializedThis; /* 6 */
2302 // }
2303 case ITEM_UninitializedThis:
2304 // nothing more to do for the above tag types
2305 break;
2306
2307 // Object_variable_info {
2308 // u1 tag = ITEM_Object; /* 7 */
2309 // u2 cpool_index;
2310 // }
2311 case ITEM_Object:
2312 {
2313 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index");
2314 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref);
2315 u2 new_cp_index = find_new_index(cpool_index);
2316 if (new_cp_index != 0) {
2317 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2318 ("mapped old cpool_index=%d", cpool_index));
2319 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
2320 cpool_index = new_cp_index;
2321 }
2322 stackmap_p_ref += 2;
2323
2324 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2325 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i,
2326 frame_type, cpool_index));
2327 } break;
2328
2329 // Uninitialized_variable_info {
2330 // u1 tag = ITEM_Uninitialized; /* 8 */
2331 // u2 offset;
2332 // }
2333 case ITEM_Uninitialized:
2334 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset");
2335 stackmap_p_ref += 2;
2336 break;
2337
2338 default:
2339 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2340 ("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag));
2341 ShouldNotReachHere();
2342 break;
2343 } // end switch (tag)
2344 } // end rewrite_cp_refs_in_verification_type_info()
2345
2346
2347 // Change the constant pool associated with klass scratch_class to
2348 // scratch_cp. If shrink is true, then scratch_cp_length elements
2349 // are copied from scratch_cp to a smaller constant pool and the
2350 // smaller constant pool is associated with scratch_class.
2351 void VM_RedefineClasses::set_new_constant_pool(
2352 ClassLoaderData* loader_data,
2353 instanceKlassHandle scratch_class, constantPoolHandle scratch_cp,
2354 int scratch_cp_length, TRAPS) {
2355 assert(scratch_cp->length() >= scratch_cp_length, "sanity check");
2356
2357 // scratch_cp is a merged constant pool and has enough space for a
2358 // worst case merge situation. We want to associate the minimum
2359 // sized constant pool with the klass to save space.
2360 constantPoolHandle smaller_cp(THREAD,
2361 ConstantPool::allocate(loader_data, scratch_cp_length, THREAD));
2362
2363 // preserve version() value in the smaller copy
2364 int version = scratch_cp->version();
2365 assert(version != 0, "sanity check");
2366 smaller_cp->set_version(version);
2367
2368 // attach klass to new constant pool
2369 // reference to the cp holder is needed for copy_operands()
2370 smaller_cp->set_pool_holder(scratch_class());
2371
2372 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
2373 scratch_cp = smaller_cp;
2374
2375 // attach new constant pool to klass
2376 scratch_class->set_constants(scratch_cp());
2377
2378 int i; // for portability
2379
2380 // update each field in klass to use new constant pool indices as needed
2381 for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) {
2382 jshort cur_index = fs.name_index();
2383 jshort new_index = find_new_index(cur_index);
2384 if (new_index != 0) {
2385 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2386 ("field-name_index change: %d to %d", cur_index, new_index));
2387 fs.set_name_index(new_index);
2388 }
2389 cur_index = fs.signature_index();
2390 new_index = find_new_index(cur_index);
2391 if (new_index != 0) {
2392 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2393 ("field-signature_index change: %d to %d", cur_index, new_index));
2394 fs.set_signature_index(new_index);
2395 }
2396 cur_index = fs.initval_index();
2397 new_index = find_new_index(cur_index);
2398 if (new_index != 0) {
2399 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2400 ("field-initval_index change: %d to %d", cur_index, new_index));
2401 fs.set_initval_index(new_index);
2402 }
2403 cur_index = fs.generic_signature_index();
2404 new_index = find_new_index(cur_index);
2405 if (new_index != 0) {
2406 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2407 ("field-generic_signature change: %d to %d", cur_index, new_index));
2408 fs.set_generic_signature_index(new_index);
2409 }
2410 } // end for each field
2411
2412 // Update constant pool indices in the inner classes info to use
2413 // new constant indices as needed. The inner classes info is a
2414 // quadruple:
2415 // (inner_class_info, outer_class_info, inner_name, inner_access_flags)
2416 InnerClassesIterator iter(scratch_class);
2417 for (; !iter.done(); iter.next()) {
2418 int cur_index = iter.inner_class_info_index();
2419 if (cur_index == 0) {
2420 continue; // JVM spec. allows null inner class refs so skip it
2421 }
2422 int new_index = find_new_index(cur_index);
2423 if (new_index != 0) {
2424 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2425 ("inner_class_info change: %d to %d", cur_index, new_index));
2426 iter.set_inner_class_info_index(new_index);
2427 }
2428 cur_index = iter.outer_class_info_index();
2429 new_index = find_new_index(cur_index);
2430 if (new_index != 0) {
2431 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2432 ("outer_class_info change: %d to %d", cur_index, new_index));
2433 iter.set_outer_class_info_index(new_index);
2434 }
2435 cur_index = iter.inner_name_index();
2436 new_index = find_new_index(cur_index);
2437 if (new_index != 0) {
2438 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2439 ("inner_name change: %d to %d", cur_index, new_index));
2440 iter.set_inner_name_index(new_index);
2441 }
2442 } // end for each inner class
2443
2444 // Attach each method in klass to the new constant pool and update
2445 // to use new constant pool indices as needed:
2446 Array<Method*>* methods = scratch_class->methods();
2447 for (i = methods->length() - 1; i >= 0; i--) {
2448 methodHandle method(THREAD, methods->at(i));
2449 method->set_constants(scratch_cp());
2450
2451 int new_index = find_new_index(method->name_index());
2452 if (new_index != 0) {
2453 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2454 ("method-name_index change: %d to %d", method->name_index(),
2455 new_index));
2456 method->set_name_index(new_index);
2457 }
2458 new_index = find_new_index(method->signature_index());
2459 if (new_index != 0) {
2460 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2461 ("method-signature_index change: %d to %d",
2462 method->signature_index(), new_index));
2463 method->set_signature_index(new_index);
2464 }
2465 new_index = find_new_index(method->generic_signature_index());
2466 if (new_index != 0) {
2467 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2468 ("method-generic_signature_index change: %d to %d",
2469 method->generic_signature_index(), new_index));
2470 method->set_generic_signature_index(new_index);
2471 }
2472
2473 // Update constant pool indices in the method's checked exception
2474 // table to use new constant indices as needed.
2475 int cext_length = method->checked_exceptions_length();
2476 if (cext_length > 0) {
2477 CheckedExceptionElement * cext_table =
2478 method->checked_exceptions_start();
2479 for (int j = 0; j < cext_length; j++) {
2480 int cur_index = cext_table[j].class_cp_index;
2481 int new_index = find_new_index(cur_index);
2482 if (new_index != 0) {
2483 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2484 ("cext-class_cp_index change: %d to %d", cur_index, new_index));
2485 cext_table[j].class_cp_index = (u2)new_index;
2486 }
2487 } // end for each checked exception table entry
2488 } // end if there are checked exception table entries
2489
2490 // Update each catch type index in the method's exception table
2491 // to use new constant pool indices as needed. The exception table
2492 // holds quadruple entries of the form:
2493 // (beg_bci, end_bci, handler_bci, klass_index)
2494
2495 ExceptionTable ex_table(method());
2496 int ext_length = ex_table.length();
2497
2498 for (int j = 0; j < ext_length; j ++) {
2499 int cur_index = ex_table.catch_type_index(j);
2500 int new_index = find_new_index(cur_index);
2501 if (new_index != 0) {
2502 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2503 ("ext-klass_index change: %d to %d", cur_index, new_index));
2504 ex_table.set_catch_type_index(j, new_index);
2505 }
2506 } // end for each exception table entry
2507
2508 // Update constant pool indices in the method's local variable
2509 // table to use new constant indices as needed. The local variable
2510 // table hold sextuple entries of the form:
2511 // (start_pc, length, name_index, descriptor_index, signature_index, slot)
2512 int lvt_length = method->localvariable_table_length();
2513 if (lvt_length > 0) {
2514 LocalVariableTableElement * lv_table =
2515 method->localvariable_table_start();
2516 for (int j = 0; j < lvt_length; j++) {
2517 int cur_index = lv_table[j].name_cp_index;
2518 int new_index = find_new_index(cur_index);
2519 if (new_index != 0) {
2520 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2521 ("lvt-name_cp_index change: %d to %d", cur_index, new_index));
2522 lv_table[j].name_cp_index = (u2)new_index;
2523 }
2524 cur_index = lv_table[j].descriptor_cp_index;
2525 new_index = find_new_index(cur_index);
2526 if (new_index != 0) {
2527 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2528 ("lvt-descriptor_cp_index change: %d to %d", cur_index,
2529 new_index));
2530 lv_table[j].descriptor_cp_index = (u2)new_index;
2531 }
2532 cur_index = lv_table[j].signature_cp_index;
2533 new_index = find_new_index(cur_index);
2534 if (new_index != 0) {
2535 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2536 ("lvt-signature_cp_index change: %d to %d", cur_index, new_index));
2537 lv_table[j].signature_cp_index = (u2)new_index;
2538 }
2539 } // end for each local variable table entry
2540 } // end if there are local variable table entries
2541
2542 rewrite_cp_refs_in_stack_map_table(method, THREAD);
2543 } // end for each method
2544 } // end set_new_constant_pool()
2545
2546
2547 void VM_RedefineClasses::adjust_array_vtable(Klass* k_oop) {
2548 ArrayKlass* ak = ArrayKlass::cast(k_oop);
2549 bool trace_name_printed = false;
2550 ak->vtable()->adjust_method_entries(_matching_old_methods,
2551 _matching_new_methods,
2552 _matching_methods_length,
2553 &trace_name_printed);
2554 }
2555
2556 // Unevolving classes may point to methods of the_class directly
2557 // from their constant pool caches, itables, and/or vtables. We
2558 // use the SystemDictionary::classes_do() facility and this helper
2559 // to fix up these pointers.
2560 //
2561 // Note: We currently don't support updating the vtable in
2562 // arrayKlassOops. See Open Issues in jvmtiRedefineClasses.hpp.
2563 void VM_RedefineClasses::adjust_cpool_cache_and_vtable(Klass* k_oop,
2564 ClassLoaderData* initiating_loader,
2565 TRAPS) {
2566 Klass *k = k_oop;
2567 if (k->oop_is_instance()) {
2568 HandleMark hm(THREAD);
2569 InstanceKlass *ik = (InstanceKlass *) k;
2570
2571 // HotSpot specific optimization! HotSpot does not currently
2572 // support delegation from the bootstrap class loader to a
2573 // user-defined class loader. This means that if the bootstrap
2574 // class loader is the initiating class loader, then it will also
2575 // be the defining class loader. This also means that classes
2576 // loaded by the bootstrap class loader cannot refer to classes
2577 // loaded by a user-defined class loader. Note: a user-defined
2578 // class loader can delegate to the bootstrap class loader.
2579 //
2580 // If the current class being redefined has a user-defined class
2581 // loader as its defining class loader, then we can skip all
2582 // classes loaded by the bootstrap class loader.
2583 bool is_user_defined =
2584 InstanceKlass::cast(_the_class_oop)->class_loader() != NULL;
2585 if (is_user_defined && ik->class_loader() == NULL) {
2586 return;
2587 }
2588
2589 // If the class being redefined is java.lang.Object, we need to fix all
2590 // array class vtables also
2591 if (_the_class_oop == SystemDictionary::Object_klass()) {
2592 ik->array_klasses_do(adjust_array_vtable);
2593 }
2594
2595 // This is a very busy routine. We don't want too much tracing
2596 // printed out.
2597 bool trace_name_printed = false;
2598
2599 // Very noisy: only enable this call if you are trying to determine
2600 // that a specific class gets found by this routine.
2601 // RC_TRACE macro has an embedded ResourceMark
2602 // RC_TRACE_WITH_THREAD(0x00100000, THREAD,
2603 // ("adjust check: name=%s", ik->external_name()));
2604 // trace_name_printed = true;
2605
2606 // Fix the vtable embedded in the_class and subclasses of the_class,
2607 // if one exists. We discard scratch_class and we don't keep an
2608 // InstanceKlass around to hold obsolete methods so we don't have
2609 // any other InstanceKlass embedded vtables to update. The vtable
2610 // holds the Method*s for virtual (but not final) methods.
2611 if (ik->vtable_length() > 0 && ik->is_subtype_of(_the_class_oop)) {
2612 // ik->vtable() creates a wrapper object; rm cleans it up
2613 ResourceMark rm(THREAD);
2614 ik->vtable()->adjust_method_entries(_matching_old_methods,
2615 _matching_new_methods,
2616 _matching_methods_length,
2617 &trace_name_printed);
2618 }
2619
2620 // If the current class has an itable and we are either redefining an
2621 // interface or if the current class is a subclass of the_class, then
2622 // we potentially have to fix the itable. If we are redefining an
2623 // interface, then we have to call adjust_method_entries() for
2624 // every InstanceKlass that has an itable since there isn't a
2625 // subclass relationship between an interface and an InstanceKlass.
2626 if (ik->itable_length() > 0 && (_the_class_oop->is_interface()
2627 || ik->is_subclass_of(_the_class_oop))) {
2628 // ik->itable() creates a wrapper object; rm cleans it up
2629 ResourceMark rm(THREAD);
2630 ik->itable()->adjust_method_entries(_matching_old_methods,
2631 _matching_new_methods,
2632 _matching_methods_length,
2633 &trace_name_printed);
2634 }
2635
2636 // The constant pools in other classes (other_cp) can refer to
2637 // methods in the_class. We have to update method information in
2638 // other_cp's cache. If other_cp has a previous version, then we
2639 // have to repeat the process for each previous version. The
2640 // constant pool cache holds the Method*s for non-virtual
2641 // methods and for virtual, final methods.
2642 //
2643 // Special case: if the current class is the_class, then new_cp
2644 // has already been attached to the_class and old_cp has already
2645 // been added as a previous version. The new_cp doesn't have any
2646 // cached references to old methods so it doesn't need to be
2647 // updated. We can simply start with the previous version(s) in
2648 // that case.
2649 constantPoolHandle other_cp;
2650 ConstantPoolCache* cp_cache;
2651
2652 if (k_oop != _the_class_oop) {
2653 // this klass' constant pool cache may need adjustment
2654 other_cp = constantPoolHandle(ik->constants());
2655 cp_cache = other_cp->cache();
2656 if (cp_cache != NULL) {
2657 cp_cache->adjust_method_entries(_matching_old_methods,
2658 _matching_new_methods,
2659 _matching_methods_length,
2660 &trace_name_printed);
2661 }
2662 }
2663 {
2664 ResourceMark rm(THREAD);
2665 // PreviousVersionInfo objects returned via PreviousVersionWalker
2666 // contain a GrowableArray of handles. We have to clean up the
2667 // GrowableArray _after_ the PreviousVersionWalker destructor
2668 // has destroyed the handles.
2669 {
2670 // the previous versions' constant pool caches may need adjustment
2671 PreviousVersionWalker pvw(ik);
2672 for (PreviousVersionInfo * pv_info = pvw.next_previous_version();
2673 pv_info != NULL; pv_info = pvw.next_previous_version()) {
2674 other_cp = pv_info->prev_constant_pool_handle();
2675 cp_cache = other_cp->cache();
2676 if (cp_cache != NULL) {
2677 cp_cache->adjust_method_entries(_matching_old_methods,
2678 _matching_new_methods,
2679 _matching_methods_length,
2680 &trace_name_printed);
2681 }
2682 }
2683 } // pvw is cleaned up
2684 } // rm is cleaned up
2685 }
2686 }
2687
2688 void VM_RedefineClasses::update_jmethod_ids() {
2689 for (int j = 0; j < _matching_methods_length; ++j) {
2690 Method* old_method = _matching_old_methods[j];
2691 jmethodID jmid = old_method->find_jmethod_id_or_null();
2692 if (jmid != NULL) {
2693 // There is a jmethodID, change it to point to the new method
2694 methodHandle new_method_h(_matching_new_methods[j]);
2695 Method::change_method_associated_with_jmethod_id(jmid, new_method_h());
2696 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j],
2697 "should be replaced");
2698 }
2699 }
2700 }
2701
2702 void VM_RedefineClasses::check_methods_and_mark_as_obsolete(
2703 BitMap *emcp_methods, int * emcp_method_count_p) {
2704 *emcp_method_count_p = 0;
2705 int obsolete_count = 0;
2706 int old_index = 0;
2707 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
2708 Method* old_method = _matching_old_methods[j];
2709 Method* new_method = _matching_new_methods[j];
2710 Method* old_array_method;
2711
2712 // Maintain an old_index into the _old_methods array by skipping
2713 // deleted methods
2714 while ((old_array_method = _old_methods->at(old_index)) != old_method) {
2715 ++old_index;
2716 }
2717
2718 if (MethodComparator::methods_EMCP(old_method, new_method)) {
2719 // The EMCP definition from JSR-163 requires the bytecodes to be
2720 // the same with the exception of constant pool indices which may
2721 // differ. However, the constants referred to by those indices
2722 // must be the same.
2723 //
2724 // We use methods_EMCP() for comparison since constant pool
2725 // merging can remove duplicate constant pool entries that were
2726 // present in the old method and removed from the rewritten new
2727 // method. A faster binary comparison function would consider the
2728 // old and new methods to be different when they are actually
2729 // EMCP.
2730 //
2731 // The old and new methods are EMCP and you would think that we
2732 // could get rid of one of them here and now and save some space.
2733 // However, the concept of EMCP only considers the bytecodes and
2734 // the constant pool entries in the comparison. Other things,
2735 // e.g., the line number table (LNT) or the local variable table
2736 // (LVT) don't count in the comparison. So the new (and EMCP)
2737 // method can have a new LNT that we need so we can't just
2738 // overwrite the new method with the old method.
2739 //
2740 // When this routine is called, we have already attached the new
2741 // methods to the_class so the old methods are effectively
2742 // overwritten. However, if an old method is still executing,
2743 // then the old method cannot be collected until sometime after
2744 // the old method call has returned. So the overwriting of old
2745 // methods by new methods will save us space except for those
2746 // (hopefully few) old methods that are still executing.
2747 //
2748 // A method refers to a ConstMethod* and this presents another
2749 // possible avenue to space savings. The ConstMethod* in the
2750 // new method contains possibly new attributes (LNT, LVT, etc).
2751 // At first glance, it seems possible to save space by replacing
2752 // the ConstMethod* in the old method with the ConstMethod*
2753 // from the new method. The old and new methods would share the
2754 // same ConstMethod* and we would save the space occupied by
2755 // the old ConstMethod*. However, the ConstMethod* contains
2756 // a back reference to the containing method. Sharing the
2757 // ConstMethod* between two methods could lead to confusion in
2758 // the code that uses the back reference. This would lead to
2759 // brittle code that could be broken in non-obvious ways now or
2760 // in the future.
2761 //
2762 // Another possibility is to copy the ConstMethod* from the new
2763 // method to the old method and then overwrite the new method with
2764 // the old method. Since the ConstMethod* contains the bytecodes
2765 // for the method embedded in the oop, this option would change
2766 // the bytecodes out from under any threads executing the old
2767 // method and make the thread's bcp invalid. Since EMCP requires
2768 // that the bytecodes be the same modulo constant pool indices, it
2769 // is straight forward to compute the correct new bcp in the new
2770 // ConstMethod* from the old bcp in the old ConstMethod*. The
2771 // time consuming part would be searching all the frames in all
2772 // of the threads to find all of the calls to the old method.
2773 //
2774 // It looks like we will have to live with the limited savings
2775 // that we get from effectively overwriting the old methods
2776 // when the new methods are attached to the_class.
2777
2778 // track which methods are EMCP for add_previous_version() call
2779 emcp_methods->set_bit(old_index);
2780 (*emcp_method_count_p)++;
2781
2782 // An EMCP method is _not_ obsolete. An obsolete method has a
2783 // different jmethodID than the current method. An EMCP method
2784 // has the same jmethodID as the current method. Having the
2785 // same jmethodID for all EMCP versions of a method allows for
2786 // a consistent view of the EMCP methods regardless of which
2787 // EMCP method you happen to have in hand. For example, a
2788 // breakpoint set in one EMCP method will work for all EMCP
2789 // versions of the method including the current one.
2790 } else {
2791 // mark obsolete methods as such
2792 old_method->set_is_obsolete();
2793 obsolete_count++;
2794
2795 // obsolete methods need a unique idnum
2796 u2 num = InstanceKlass::cast(_the_class_oop)->next_method_idnum();
2797 if (num != ConstMethod::UNSET_IDNUM) {
2798 // u2 old_num = old_method->method_idnum();
2799 old_method->set_method_idnum(num);
2800 // TO DO: attach obsolete annotations to obsolete method's new idnum
2801 }
2802 // With tracing we try not to "yack" too much. The position of
2803 // this trace assumes there are fewer obsolete methods than
2804 // EMCP methods.
2805 RC_TRACE(0x00000100, ("mark %s(%s) as obsolete",
2806 old_method->name()->as_C_string(),
2807 old_method->signature()->as_C_string()));
2808 }
2809 old_method->set_is_old();
2810 }
2811 for (int i = 0; i < _deleted_methods_length; ++i) {
2812 Method* old_method = _deleted_methods[i];
2813
2814 assert(old_method->vtable_index() < 0,
2815 "cannot delete methods with vtable entries");;
2816
2817 // Mark all deleted methods as old and obsolete
2818 old_method->set_is_old();
2819 old_method->set_is_obsolete();
2820 ++obsolete_count;
2821 // With tracing we try not to "yack" too much. The position of
2822 // this trace assumes there are fewer obsolete methods than
2823 // EMCP methods.
2824 RC_TRACE(0x00000100, ("mark deleted %s(%s) as obsolete",
2825 old_method->name()->as_C_string(),
2826 old_method->signature()->as_C_string()));
2827 }
2828 assert((*emcp_method_count_p + obsolete_count) == _old_methods->length(),
2829 "sanity check");
2830 RC_TRACE(0x00000100, ("EMCP_cnt=%d, obsolete_cnt=%d", *emcp_method_count_p,
2831 obsolete_count));
2832 }
2833
2834 // This internal class transfers the native function registration from old methods
2835 // to new methods. It is designed to handle both the simple case of unchanged
2836 // native methods and the complex cases of native method prefixes being added and/or
2837 // removed.
2838 // It expects only to be used during the VM_RedefineClasses op (a safepoint).
2839 //
2840 // This class is used after the new methods have been installed in "the_class".
2841 //
2842 // So, for example, the following must be handled. Where 'm' is a method and
2843 // a number followed by an underscore is a prefix.
2844 //
2845 // Old Name New Name
2846 // Simple transfer to new method m -> m
2847 // Add prefix m -> 1_m
2848 // Remove prefix 1_m -> m
2849 // Simultaneous add of prefixes m -> 3_2_1_m
2850 // Simultaneous removal of prefixes 3_2_1_m -> m
2851 // Simultaneous add and remove 1_m -> 2_m
2852 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m
2853 //
2854 class TransferNativeFunctionRegistration {
2855 private:
2856 instanceKlassHandle the_class;
2857 int prefix_count;
2858 char** prefixes;
2859
2860 // Recursively search the binary tree of possibly prefixed method names.
2861 // Iteration could be used if all agents were well behaved. Full tree walk is
2862 // more resilent to agents not cleaning up intermediate methods.
2863 // Branch at each depth in the binary tree is:
2864 // (1) without the prefix.
2865 // (2) with the prefix.
2866 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
2867 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len,
2868 Symbol* signature) {
2869 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len);
2870 if (name_symbol != NULL) {
2871 Method* method = the_class()->lookup_method(name_symbol, signature);
2872 if (method != NULL) {
2873 // Even if prefixed, intermediate methods must exist.
2874 if (method->is_native()) {
2875 // Wahoo, we found a (possibly prefixed) version of the method, return it.
2876 return method;
2877 }
2878 if (depth < prefix_count) {
2879 // Try applying further prefixes (other than this one).
2880 method = search_prefix_name_space(depth+1, name_str, name_len, signature);
2881 if (method != NULL) {
2882 return method; // found
2883 }
2884
2885 // Try adding this prefix to the method name and see if it matches
2886 // another method name.
2887 char* prefix = prefixes[depth];
2888 size_t prefix_len = strlen(prefix);
2889 size_t trial_len = name_len + prefix_len;
2890 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
2891 strcpy(trial_name_str, prefix);
2892 strcat(trial_name_str, name_str);
2893 method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
2894 signature);
2895 if (method != NULL) {
2896 // If found along this branch, it was prefixed, mark as such
2897 method->set_is_prefixed_native();
2898 return method; // found
2899 }
2900 }
2901 }
2902 }
2903 return NULL; // This whole branch bore nothing
2904 }
2905
2906 // Return the method name with old prefixes stripped away.
2907 char* method_name_without_prefixes(Method* method) {
2908 Symbol* name = method->name();
2909 char* name_str = name->as_utf8();
2910
2911 // Old prefixing may be defunct, strip prefixes, if any.
2912 for (int i = prefix_count-1; i >= 0; i--) {
2913 char* prefix = prefixes[i];
2914 size_t prefix_len = strlen(prefix);
2915 if (strncmp(prefix, name_str, prefix_len) == 0) {
2916 name_str += prefix_len;
2917 }
2918 }
2919 return name_str;
2920 }
2921
2922 // Strip any prefixes off the old native method, then try to find a
2923 // (possibly prefixed) new native that matches it.
2924 Method* strip_and_search_for_new_native(Method* method) {
2925 ResourceMark rm;
2926 char* name_str = method_name_without_prefixes(method);
2927 return search_prefix_name_space(0, name_str, strlen(name_str),
2928 method->signature());
2929 }
2930
2931 public:
2932
2933 // Construct a native method transfer processor for this class.
2934 TransferNativeFunctionRegistration(instanceKlassHandle _the_class) {
2935 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
2936
2937 the_class = _the_class;
2938 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
2939 }
2940
2941 // Attempt to transfer any of the old or deleted methods that are native
2942 void transfer_registrations(Method** old_methods, int methods_length) {
2943 for (int j = 0; j < methods_length; j++) {
2944 Method* old_method = old_methods[j];
2945
2946 if (old_method->is_native() && old_method->has_native_function()) {
2947 Method* new_method = strip_and_search_for_new_native(old_method);
2948 if (new_method != NULL) {
2949 // Actually set the native function in the new method.
2950 // Redefine does not send events (except CFLH), certainly not this
2951 // behind the scenes re-registration.
2952 new_method->set_native_function(old_method->native_function(),
2953 !Method::native_bind_event_is_interesting);
2954 }
2955 }
2956 }
2957 }
2958 };
2959
2960 // Don't lose the association between a native method and its JNI function.
2961 void VM_RedefineClasses::transfer_old_native_function_registrations(instanceKlassHandle the_class) {
2962 TransferNativeFunctionRegistration transfer(the_class);
2963 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length);
2964 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length);
2965 }
2966
2967 // Deoptimize all compiled code that depends on this class.
2968 //
2969 // If the can_redefine_classes capability is obtained in the onload
2970 // phase then the compiler has recorded all dependencies from startup.
2971 // In that case we need only deoptimize and throw away all compiled code
2972 // that depends on the class.
2973 //
2974 // If can_redefine_classes is obtained sometime after the onload
2975 // phase then the dependency information may be incomplete. In that case
2976 // the first call to RedefineClasses causes all compiled code to be
2977 // thrown away. As can_redefine_classes has been obtained then
2978 // all future compilations will record dependencies so second and
2979 // subsequent calls to RedefineClasses need only throw away code
2980 // that depends on the class.
2981 //
2982 void VM_RedefineClasses::flush_dependent_code(instanceKlassHandle k_h, TRAPS) {
2983 assert_locked_or_safepoint(Compile_lock);
2984
2985 // All dependencies have been recorded from startup or this is a second or
2986 // subsequent use of RedefineClasses
2987 if (JvmtiExport::all_dependencies_are_recorded()) {
2988 Universe::flush_evol_dependents_on(k_h);
2989 } else {
2990 CodeCache::mark_all_nmethods_for_deoptimization();
2991
2992 ResourceMark rm(THREAD);
2993 DeoptimizationMarker dm;
2994
2995 // Deoptimize all activations depending on marked nmethods
2996 Deoptimization::deoptimize_dependents();
2997
2998 // Make the dependent methods not entrant (in VM_Deoptimize they are made zombies)
2999 CodeCache::make_marked_nmethods_not_entrant();
3000
3001 // From now on we know that the dependency information is complete
3002 JvmtiExport::set_all_dependencies_are_recorded(true);
3003 }
3004 }
3005
3006 void VM_RedefineClasses::compute_added_deleted_matching_methods() {
3007 Method* old_method;
3008 Method* new_method;
3009
3010 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3011 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3012 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length());
3013 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3014
3015 _matching_methods_length = 0;
3016 _deleted_methods_length = 0;
3017 _added_methods_length = 0;
3018
3019 int nj = 0;
3020 int oj = 0;
3021 while (true) {
3022 if (oj >= _old_methods->length()) {
3023 if (nj >= _new_methods->length()) {
3024 break; // we've looked at everything, done
3025 }
3026 // New method at the end
3027 new_method = _new_methods->at(nj);
3028 _added_methods[_added_methods_length++] = new_method;
3029 ++nj;
3030 } else if (nj >= _new_methods->length()) {
3031 // Old method, at the end, is deleted
3032 old_method = _old_methods->at(oj);
3033 _deleted_methods[_deleted_methods_length++] = old_method;
3034 ++oj;
3035 } else {
3036 old_method = _old_methods->at(oj);
3037 new_method = _new_methods->at(nj);
3038 if (old_method->name() == new_method->name()) {
3039 if (old_method->signature() == new_method->signature()) {
3040 _matching_old_methods[_matching_methods_length ] = old_method;
3041 _matching_new_methods[_matching_methods_length++] = new_method;
3042 ++nj;
3043 ++oj;
3044 } else {
3045 // added overloaded have already been moved to the end,
3046 // so this is a deleted overloaded method
3047 _deleted_methods[_deleted_methods_length++] = old_method;
3048 ++oj;
3049 }
3050 } else { // names don't match
3051 if (old_method->name()->fast_compare(new_method->name()) > 0) {
3052 // new method
3053 _added_methods[_added_methods_length++] = new_method;
3054 ++nj;
3055 } else {
3056 // deleted method
3057 _deleted_methods[_deleted_methods_length++] = old_method;
3058 ++oj;
3059 }
3060 }
3061 }
3062 }
3063 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
3064 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
3065 }
3066
3067
3068
3069 // Install the redefinition of a class:
3070 // - house keeping (flushing breakpoints and caches, deoptimizing
3071 // dependent compiled code)
3072 // - replacing parts in the_class with parts from scratch_class
3073 // - adding a weak reference to track the obsolete but interesting
3074 // parts of the_class
3075 // - adjusting constant pool caches and vtables in other classes
3076 // that refer to methods in the_class. These adjustments use the
3077 // SystemDictionary::classes_do() facility which only allows
3078 // a helper method to be specified. The interesting parameters
3079 // that we would like to pass to the helper method are saved in
3080 // static global fields in the VM operation.
3081 void VM_RedefineClasses::redefine_single_class(jclass the_jclass,
3082 Klass* scratch_class_oop, TRAPS) {
3083
3084 HandleMark hm(THREAD); // make sure handles from this call are freed
3085 RC_TIMER_START(_timer_rsc_phase1);
3086
3087 instanceKlassHandle scratch_class(scratch_class_oop);
3088
3089 oop the_class_mirror = JNIHandles::resolve_non_null(the_jclass);
3090 Klass* the_class_oop = java_lang_Class::as_Klass(the_class_mirror);
3091 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
3092
3093 // Remove all breakpoints in methods of this class
3094 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
3095 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class_oop);
3096
3097 if (the_class_oop == Universe::reflect_invoke_cache()->klass()) {
3098 // We are redefining java.lang.reflect.Method. Method.invoke() is
3099 // cached and users of the cache care about each active version of
3100 // the method so we have to track this previous version.
3101 // Do this before methods get switched
3102 Universe::reflect_invoke_cache()->add_previous_version(
3103 the_class->method_with_idnum(Universe::reflect_invoke_cache()->method_idnum()));
3104 }
3105
3106 // Deoptimize all compiled code that depends on this class
3107 flush_dependent_code(the_class, THREAD);
3108
3109 _old_methods = the_class->methods();
3110 _new_methods = scratch_class->methods();
3111 _the_class_oop = the_class_oop;
3112 compute_added_deleted_matching_methods();
3113 update_jmethod_ids();
3114
3115 // Attach new constant pool to the original klass. The original
3116 // klass still refers to the old constant pool (for now).
3117 scratch_class->constants()->set_pool_holder(the_class());
3118
3119 #if 0
3120 // In theory, with constant pool merging in place we should be able
3121 // to save space by using the new, merged constant pool in place of
3122 // the old constant pool(s). By "pool(s)" I mean the constant pool in
3123 // the klass version we are replacing now and any constant pool(s) in
3124 // previous versions of klass. Nice theory, doesn't work in practice.
3125 // When this code is enabled, even simple programs throw NullPointer
3126 // exceptions. I'm guessing that this is caused by some constant pool
3127 // cache difference between the new, merged constant pool and the
3128 // constant pool that was just being used by the klass. I'm keeping
3129 // this code around to archive the idea, but the code has to remain
3130 // disabled for now.
3131
3132 // Attach each old method to the new constant pool. This can be
3133 // done here since we are past the bytecode verification and
3134 // constant pool optimization phases.
3135 for (int i = _old_methods->length() - 1; i >= 0; i--) {
3136 Method* method = _old_methods->at(i);
3137 method->set_constants(scratch_class->constants());
3138 }
3139
3140 {
3141 // walk all previous versions of the klass
3142 InstanceKlass *ik = (InstanceKlass *)the_class();
3143 PreviousVersionWalker pvw(ik);
3144 instanceKlassHandle ikh;
3145 do {
3146 ikh = pvw.next_previous_version();
3147 if (!ikh.is_null()) {
3148 ik = ikh();
3149
3150 // attach previous version of klass to the new constant pool
3151 ik->set_constants(scratch_class->constants());
3152
3153 // Attach each method in the previous version of klass to the
3154 // new constant pool
3155 Array<Method*>* prev_methods = ik->methods();
3156 for (int i = prev_methods->length() - 1; i >= 0; i--) {
3157 Method* method = prev_methods->at(i);
3158 method->set_constants(scratch_class->constants());
3159 }
3160 }
3161 } while (!ikh.is_null());
3162 }
3163 #endif
3164
3165 // Replace methods and constantpool
3166 the_class->set_methods(_new_methods);
3167 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods,
3168 // and to be able to undo operation easily.
3169
3170 ConstantPool* old_constants = the_class->constants();
3171 the_class->set_constants(scratch_class->constants());
3172 scratch_class->set_constants(old_constants); // See the previous comment.
3173 #if 0
3174 // We are swapping the guts of "the new class" with the guts of "the
3175 // class". Since the old constant pool has just been attached to "the
3176 // new class", it seems logical to set the pool holder in the old
3177 // constant pool also. However, doing this will change the observable
3178 // class hierarchy for any old methods that are still executing. A
3179 // method can query the identity of its "holder" and this query uses
3180 // the method's constant pool link to find the holder. The change in
3181 // holding class from "the class" to "the new class" can confuse
3182 // things.
3183 //
3184 // Setting the old constant pool's holder will also cause
3185 // verification done during vtable initialization below to fail.
3186 // During vtable initialization, the vtable's class is verified to be
3187 // a subtype of the method's holder. The vtable's class is "the
3188 // class" and the method's holder is gotten from the constant pool
3189 // link in the method itself. For "the class"'s directly implemented
3190 // methods, the method holder is "the class" itself (as gotten from
3191 // the new constant pool). The check works fine in this case. The
3192 // check also works fine for methods inherited from super classes.
3193 //
3194 // Miranda methods are a little more complicated. A miranda method is
3195 // provided by an interface when the class implementing the interface
3196 // does not provide its own method. These interfaces are implemented
3197 // internally as an InstanceKlass. These special instanceKlasses
3198 // share the constant pool of the class that "implements" the
3199 // interface. By sharing the constant pool, the method holder of a
3200 // miranda method is the class that "implements" the interface. In a
3201 // non-redefine situation, the subtype check works fine. However, if
3202 // the old constant pool's pool holder is modified, then the check
3203 // fails because there is no class hierarchy relationship between the
3204 // vtable's class and "the new class".
3205
3206 old_constants->set_pool_holder(scratch_class());
3207 #endif
3208
3209 // track which methods are EMCP for add_previous_version() call below
3210 BitMap emcp_methods(_old_methods->length());
3211 int emcp_method_count = 0;
3212 emcp_methods.clear(); // clears 0..(length() - 1)
3213 check_methods_and_mark_as_obsolete(&emcp_methods, &emcp_method_count);
3214 transfer_old_native_function_registrations(the_class);
3215
3216 // The class file bytes from before any retransformable agents mucked
3217 // with them was cached on the scratch class, move to the_class.
3218 // Note: we still want to do this if nothing needed caching since it
3219 // should get cleared in the_class too.
3220 if (the_class->get_cached_class_file_bytes() == 0) {
3221 // the_class doesn't have a cache yet so copy it
3222 the_class->set_cached_class_file(
3223 scratch_class->get_cached_class_file_bytes(),
3224 scratch_class->get_cached_class_file_len());
3225 }
3226 #ifndef PRODUCT
3227 else {
3228 assert(the_class->get_cached_class_file_bytes() ==
3229 scratch_class->get_cached_class_file_bytes(), "cache ptrs must match");
3230 assert(the_class->get_cached_class_file_len() ==
3231 scratch_class->get_cached_class_file_len(), "cache lens must match");
3232 }
3233 #endif
3234
3235 // Replace inner_classes
3236 Array<u2>* old_inner_classes = the_class->inner_classes();
3237 the_class->set_inner_classes(scratch_class->inner_classes());
3238 scratch_class->set_inner_classes(old_inner_classes);
3239
3240 // Initialize the vtable and interface table after
3241 // methods have been rewritten
3242 {
3243 ResourceMark rm(THREAD);
3244 // no exception should happen here since we explicitly
3245 // do not check loader constraints.
3246 // compare_and_normalize_class_versions has already checked:
3247 // - classloaders unchanged, signatures unchanged
3248 // - all instanceKlasses for redefined classes reused & contents updated
3249 the_class->vtable()->initialize_vtable(false, THREAD);
3250 the_class->itable()->initialize_itable(false, THREAD);
3251 assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())), "redefine exception");
3252 }
3253
3254 // Leave arrays of jmethodIDs and itable index cache unchanged
3255
3256 // Copy the "source file name" attribute from new class version
3257 the_class->set_source_file_name(scratch_class->source_file_name());
3258
3259 // Copy the "source debug extension" attribute from new class version
3260 the_class->set_source_debug_extension(
3261 scratch_class->source_debug_extension(),
3262 scratch_class->source_debug_extension() == NULL ? 0 :
3263 (int)strlen(scratch_class->source_debug_extension()));
3264
3265 // Use of javac -g could be different in the old and the new
3266 if (scratch_class->access_flags().has_localvariable_table() !=
3267 the_class->access_flags().has_localvariable_table()) {
3268
3269 AccessFlags flags = the_class->access_flags();
3270 if (scratch_class->access_flags().has_localvariable_table()) {
3271 flags.set_has_localvariable_table();
3272 } else {
3273 flags.clear_has_localvariable_table();
3274 }
3275 the_class->set_access_flags(flags);
3276 }
3277
3278 // Since there is currently no rewriting of type annotations indexes
3279 // into the CP, we null out type annotations on scratch_class before
3280 // we swap annotations with the_class rather than facing the
3281 // possibility of shipping annotations with broken indexes to
3282 // Java-land.
3283 Annotations* new_annotations = scratch_class->annotations();
3284 if (new_annotations != NULL) {
3285 Annotations* new_type_annotations = new_annotations->type_annotations();
3286 if (new_type_annotations != NULL) {
3287 MetadataFactory::free_metadata(scratch_class->class_loader_data(), new_type_annotations);
3288 new_annotations->set_type_annotations(NULL);
3289 }
3290 }
3291 // Swap annotation fields values
3292 Annotations* old_annotations = the_class->annotations();
3293 the_class->set_annotations(scratch_class->annotations());
3294 scratch_class->set_annotations(old_annotations);
3295
3296 // Replace minor version number of class file
3297 u2 old_minor_version = the_class->minor_version();
3298 the_class->set_minor_version(scratch_class->minor_version());
3299 scratch_class->set_minor_version(old_minor_version);
3300
3301 // Replace major version number of class file
3302 u2 old_major_version = the_class->major_version();
3303 the_class->set_major_version(scratch_class->major_version());
3304 scratch_class->set_major_version(old_major_version);
3305
3306 // Replace CP indexes for class and name+type of enclosing method
3307 u2 old_class_idx = the_class->enclosing_method_class_index();
3308 u2 old_method_idx = the_class->enclosing_method_method_index();
3309 the_class->set_enclosing_method_indices(
3310 scratch_class->enclosing_method_class_index(),
3311 scratch_class->enclosing_method_method_index());
3312 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx);
3313
3314 // keep track of previous versions of this class
3315 the_class->add_previous_version(scratch_class, &emcp_methods,
3316 emcp_method_count);
3317
3318 RC_TIMER_STOP(_timer_rsc_phase1);
3319 RC_TIMER_START(_timer_rsc_phase2);
3320
3321 // Adjust constantpool caches and vtables for all classes
3322 // that reference methods of the evolved class.
3323 SystemDictionary::classes_do(adjust_cpool_cache_and_vtable, THREAD);
3324
3325 // Fix Resolution Error table also to remove old constant pools
3326 SystemDictionary::delete_resolution_error(old_constants);
3327
3328 if (the_class->oop_map_cache() != NULL) {
3329 // Flush references to any obsolete methods from the oop map cache
3330 // so that obsolete methods are not pinned.
3331 the_class->oop_map_cache()->flush_obsolete_entries();
3332 }
3333
3334 // increment the classRedefinedCount field in the_class and in any
3335 // direct and indirect subclasses of the_class
3336 increment_class_counter((InstanceKlass *)the_class(), THREAD);
3337
3338 // RC_TRACE macro has an embedded ResourceMark
3339 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
3340 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)",
3341 the_class->external_name(),
3342 java_lang_Class::classRedefinedCount(the_class_mirror),
3343 os::available_memory() >> 10));
3344
3345 RC_TIMER_STOP(_timer_rsc_phase2);
3346 } // end redefine_single_class()
3347
3348
3349 // Increment the classRedefinedCount field in the specific InstanceKlass
3350 // and in all direct and indirect subclasses.
3351 void VM_RedefineClasses::increment_class_counter(InstanceKlass *ik, TRAPS) {
3352 oop class_mirror = ik->java_mirror();
3353 Klass* class_oop = java_lang_Class::as_Klass(class_mirror);
3354 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
3355 java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
3356
3357 if (class_oop != _the_class_oop) {
3358 // _the_class_oop count is printed at end of redefine_single_class()
3359 RC_TRACE_WITH_THREAD(0x00000008, THREAD,
3360 ("updated count in subclass=%s to %d", ik->external_name(), new_count));
3361 }
3362
3363 for (Klass *subk = ik->subklass(); subk != NULL;
3364 subk = subk->next_sibling()) {
3365 if (subk->oop_is_instance()) {
3366 // Only update instanceKlasses
3367 InstanceKlass *subik = (InstanceKlass*)subk;
3368 // recursively do subclasses of the current subclass
3369 increment_class_counter(subik, THREAD);
3370 }
3371 }
3372 }
3373
3374 #ifndef PRODUCT
3375 void VM_RedefineClasses::check_class(Klass* k_oop,
3376 ClassLoaderData* initiating_loader,
3377 TRAPS) {
3378 Klass *k = k_oop;
3379 if (k->oop_is_instance()) {
3380 HandleMark hm(THREAD);
3381 InstanceKlass *ik = (InstanceKlass *) k;
3382
3383 if (ik->vtable_length() > 0) {
3384 ResourceMark rm(THREAD);
3385 if (!ik->vtable()->check_no_old_entries()) {
3386 tty->print_cr("klassVtable::check_no_old_entries failure -- OLD method found -- class: %s", ik->signature_name());
3387 ik->vtable()->dump_vtable();
3388 assert(false, "OLD method found");
3389 }
3390 }
3391 if (ik->itable_length() > 0) {
3392 ResourceMark rm(THREAD);
3393 if (!ik->itable()->check_no_old_entries()) {
3394 tty->print_cr("klassItable::check_no_old_entries failure -- OLD method found -- class: %s", ik->signature_name());
3395 assert(false, "OLD method found");
3396 }
3397 }
3398 // Check that the constant pool cache has no deleted entries.
3399 if (ik->constants() != NULL &&
3400 ik->constants()->cache() != NULL &&
3401 !ik->constants()->cache()->check_no_old_entries()) {
3402 tty->print_cr("klassVtable::check_no_old_entries failure -- OLD method found -- class: %s", ik->signature_name());
3403 assert(false, "OLD method found");
3404 }
3405 }
3406 }
3407
3408 void VM_RedefineClasses::dump_methods() {
3409 int j;
3410 tty->print_cr("_old_methods --");
3411 for (j = 0; j < _old_methods->length(); ++j) {
3412 Method* m = _old_methods->at(j);
3413 tty->print("%4d (%5d) ", j, m->vtable_index());
3414 m->access_flags().print_on(tty);
3415 tty->print(" -- ");
3416 m->print_name(tty);
3417 tty->cr();
3418 }
3419 tty->print_cr("_new_methods --");
3420 for (j = 0; j < _new_methods->length(); ++j) {
3421 Method* m = _new_methods->at(j);
3422 tty->print("%4d (%5d) ", j, m->vtable_index());
3423 m->access_flags().print_on(tty);
3424 tty->print(" -- ");
3425 m->print_name(tty);
3426 tty->cr();
3427 }
3428 tty->print_cr("_matching_(old/new)_methods --");
3429 for (j = 0; j < _matching_methods_length; ++j) {
3430 Method* m = _matching_old_methods[j];
3431 tty->print("%4d (%5d) ", j, m->vtable_index());
3432 m->access_flags().print_on(tty);
3433 tty->print(" -- ");
3434 m->print_name(tty);
3435 tty->cr();
3436 m = _matching_new_methods[j];
3437 tty->print(" (%5d) ", m->vtable_index());
3438 m->access_flags().print_on(tty);
3439 tty->cr();
3440 }
3441 tty->print_cr("_deleted_methods --");
3442 for (j = 0; j < _deleted_methods_length; ++j) {
3443 Method* m = _deleted_methods[j];
3444 tty->print("%4d (%5d) ", j, m->vtable_index());
3445 m->access_flags().print_on(tty);
3446 tty->print(" -- ");
3447 m->print_name(tty);
3448 tty->cr();
3449 }
3450 tty->print_cr("_added_methods --");
3451 for (j = 0; j < _added_methods_length; ++j) {
3452 Method* m = _added_methods[j];
3453 tty->print("%4d (%5d) ", j, m->vtable_index());
3454 m->access_flags().print_on(tty);
3455 tty->print(" -- ");
3456 m->print_name(tty);
3457 tty->cr();
3458 }
3459 }
3460 #endif
--- EOF ---