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 // check_class() is optionally called for product bits, but is
158 // always called for non-product bits.
159 #ifdef PRODUCT
160 if (RC_TRACE_ENABLED(0x00004000)) {
161 #endif
162 RC_TRACE_WITH_THREAD(0x00004000, thread, ("calling check_class"));
163 SystemDictionary::classes_do(check_class, thread);
164 #ifdef PRODUCT
165 }
166 #endif
167 }
168
169 void VM_RedefineClasses::doit_epilogue() {
170 // Free os::malloc allocated memory.
171 os::free(_scratch_classes);
172
173 if (RC_TRACE_ENABLED(0x00000004)) {
174 // Used to have separate timers for "doit" and "all", but the timer
175 // overhead skewed the measurements.
176 jlong doit_time = _timer_rsc_phase1.milliseconds() +
177 _timer_rsc_phase2.milliseconds();
178 jlong all_time = _timer_vm_op_prologue.milliseconds() + doit_time;
179
180 RC_TRACE(0x00000004, ("vm_op: all=" UINT64_FORMAT
181 " prologue=" UINT64_FORMAT " doit=" UINT64_FORMAT, all_time,
182 _timer_vm_op_prologue.milliseconds(), doit_time));
183 RC_TRACE(0x00000004,
184 ("redefine_single_class: phase1=" UINT64_FORMAT " phase2=" UINT64_FORMAT,
185 _timer_rsc_phase1.milliseconds(), _timer_rsc_phase2.milliseconds()));
186 }
187 }
188
189 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) {
190 // classes for primitives cannot be redefined
191 if (java_lang_Class::is_primitive(klass_mirror)) {
192 return false;
193 }
194 Klass* the_class_oop = java_lang_Class::as_Klass(klass_mirror);
195 // classes for arrays cannot be redefined
196 if (the_class_oop == NULL || !the_class_oop->oop_is_instance()) {
197 return false;
198 }
199 return true;
200 }
201
202 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p
203 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For
204 // direct CP entries, there is just the current entry to append. For
205 // indirect and double-indirect CP entries, there are zero or more
206 // referenced CP entries along with the current entry to append.
207 // Indirect and double-indirect CP entries are handled by recursive
208 // calls to append_entry() as needed. The referenced CP entries are
209 // always appended to *merge_cp_p before the referee CP entry. These
210 // referenced CP entries may already exist in *merge_cp_p in which case
211 // there is nothing extra to append and only the current entry is
212 // appended.
213 void VM_RedefineClasses::append_entry(constantPoolHandle scratch_cp,
214 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p,
215 TRAPS) {
216
217 // append is different depending on entry tag type
218 switch (scratch_cp->tag_at(scratch_i).value()) {
219
220 // The old verifier is implemented outside the VM. It loads classes,
221 // but does not resolve constant pool entries directly so we never
222 // see Class entries here with the old verifier. Similarly the old
223 // verifier does not like Class entries in the input constant pool.
224 // The split-verifier is implemented in the VM so it can optionally
225 // and directly resolve constant pool entries to load classes. The
226 // split-verifier can accept either Class entries or UnresolvedClass
227 // entries in the input constant pool. We revert the appended copy
228 // back to UnresolvedClass so that either verifier will be happy
229 // with the constant pool entry.
230 case JVM_CONSTANT_Class:
231 {
232 // revert the copy to JVM_CONSTANT_UnresolvedClass
233 (*merge_cp_p)->unresolved_klass_at_put(*merge_cp_length_p,
234 scratch_cp->klass_name_at(scratch_i));
235
236 if (scratch_i != *merge_cp_length_p) {
237 // The new entry in *merge_cp_p is at a different index than
238 // the new entry in scratch_cp so we need to map the index values.
239 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
240 }
241 (*merge_cp_length_p)++;
242 } break;
243
244 // these are direct CP entries so they can be directly appended,
245 // but double and long take two constant pool entries
246 case JVM_CONSTANT_Double: // fall through
247 case JVM_CONSTANT_Long:
248 {
249 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
250 THREAD);
251
252 if (scratch_i != *merge_cp_length_p) {
253 // The new entry in *merge_cp_p is at a different index than
254 // the new entry in scratch_cp so we need to map the index values.
255 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
256 }
257 (*merge_cp_length_p) += 2;
258 } break;
259
260 // these are direct CP entries so they can be directly appended
261 case JVM_CONSTANT_Float: // fall through
262 case JVM_CONSTANT_Integer: // fall through
263 case JVM_CONSTANT_Utf8: // fall through
264
265 // This was an indirect CP entry, but it has been changed into
266 // Symbol*s so this entry can be directly appended.
267 case JVM_CONSTANT_String: // fall through
268
269 // These were indirect CP entries, but they have been changed into
270 // Symbol*s so these entries can be directly appended.
271 case JVM_CONSTANT_UnresolvedClass: // fall through
272 {
273 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
274 THREAD);
275
276 if (scratch_i != *merge_cp_length_p) {
277 // The new entry in *merge_cp_p is at a different index than
278 // the new entry in scratch_cp so we need to map the index values.
279 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
280 }
281 (*merge_cp_length_p)++;
282 } break;
283
284 // this is an indirect CP entry so it needs special handling
285 case JVM_CONSTANT_NameAndType:
286 {
287 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i);
288 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p,
289 merge_cp_length_p, THREAD);
290
291 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i);
292 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i,
293 merge_cp_p, merge_cp_length_p,
294 THREAD);
295
296 // If the referenced entries already exist in *merge_cp_p, then
297 // both new_name_ref_i and new_signature_ref_i will both be 0.
298 // In that case, all we are appending is the current entry.
299 if (new_name_ref_i != name_ref_i) {
300 RC_TRACE(0x00080000,
301 ("NameAndType entry@%d name_ref_index change: %d to %d",
302 *merge_cp_length_p, name_ref_i, new_name_ref_i));
303 }
304 if (new_signature_ref_i != signature_ref_i) {
305 RC_TRACE(0x00080000,
306 ("NameAndType entry@%d signature_ref_index change: %d to %d",
307 *merge_cp_length_p, signature_ref_i, new_signature_ref_i));
308 }
309
310 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p,
311 new_name_ref_i, new_signature_ref_i);
312 if (scratch_i != *merge_cp_length_p) {
313 // The new entry in *merge_cp_p is at a different index than
314 // the new entry in scratch_cp so we need to map the index values.
315 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
316 }
317 (*merge_cp_length_p)++;
318 } break;
319
320 // this is a double-indirect CP entry so it needs special handling
321 case JVM_CONSTANT_Fieldref: // fall through
322 case JVM_CONSTANT_InterfaceMethodref: // fall through
323 case JVM_CONSTANT_Methodref:
324 {
325 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i);
326 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i,
327 merge_cp_p, merge_cp_length_p, THREAD);
328
329 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i);
330 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i,
331 merge_cp_p, merge_cp_length_p, THREAD);
332
333 const char *entry_name;
334 switch (scratch_cp->tag_at(scratch_i).value()) {
335 case JVM_CONSTANT_Fieldref:
336 entry_name = "Fieldref";
337 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i,
338 new_name_and_type_ref_i);
339 break;
340 case JVM_CONSTANT_InterfaceMethodref:
341 entry_name = "IFMethodref";
342 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p,
343 new_klass_ref_i, new_name_and_type_ref_i);
344 break;
345 case JVM_CONSTANT_Methodref:
346 entry_name = "Methodref";
347 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i,
348 new_name_and_type_ref_i);
349 break;
350 default:
351 guarantee(false, "bad switch");
352 break;
353 }
354
355 if (klass_ref_i != new_klass_ref_i) {
356 RC_TRACE(0x00080000, ("%s entry@%d class_index changed: %d to %d",
357 entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i));
358 }
359 if (name_and_type_ref_i != new_name_and_type_ref_i) {
360 RC_TRACE(0x00080000,
361 ("%s entry@%d name_and_type_index changed: %d to %d",
362 entry_name, *merge_cp_length_p, name_and_type_ref_i,
363 new_name_and_type_ref_i));
364 }
365
366 if (scratch_i != *merge_cp_length_p) {
367 // The new entry in *merge_cp_p is at a different index than
368 // the new entry in scratch_cp so we need to map the index values.
369 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
370 }
371 (*merge_cp_length_p)++;
372 } break;
373
374 // this is an indirect CP entry so it needs special handling
375 case JVM_CONSTANT_MethodType:
376 {
377 int ref_i = scratch_cp->method_type_index_at(scratch_i);
378 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
379 merge_cp_length_p, THREAD);
380 if (new_ref_i != ref_i) {
381 RC_TRACE(0x00080000,
382 ("MethodType entry@%d ref_index change: %d to %d",
383 *merge_cp_length_p, ref_i, new_ref_i));
384 }
385 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i);
386 if (scratch_i != *merge_cp_length_p) {
387 // The new entry in *merge_cp_p is at a different index than
388 // the new entry in scratch_cp so we need to map the index values.
389 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
390 }
391 (*merge_cp_length_p)++;
392 } break;
393
394 // this is an indirect CP entry so it needs special handling
395 case JVM_CONSTANT_MethodHandle:
396 {
397 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i);
398 int ref_i = scratch_cp->method_handle_index_at(scratch_i);
399 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
400 merge_cp_length_p, THREAD);
401 if (new_ref_i != ref_i) {
402 RC_TRACE(0x00080000,
403 ("MethodHandle entry@%d ref_index change: %d to %d",
404 *merge_cp_length_p, ref_i, new_ref_i));
405 }
406 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i);
407 if (scratch_i != *merge_cp_length_p) {
408 // The new entry in *merge_cp_p is at a different index than
409 // the new entry in scratch_cp so we need to map the index values.
410 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
411 }
412 (*merge_cp_length_p)++;
413 } break;
414
415 // this is an indirect CP entry so it needs special handling
416 case JVM_CONSTANT_InvokeDynamic:
417 {
418 // TBD: cross-checks and possible extra appends into CP and bsm operands
419 // are needed as well. This issue is tracked by a separate bug 8007037.
420 int bss_idx = scratch_cp->invoke_dynamic_bootstrap_specifier_index(scratch_i);
421
422 int ref_i = scratch_cp->invoke_dynamic_name_and_type_ref_index_at(scratch_i);
423 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
424 merge_cp_length_p, THREAD);
425 if (new_ref_i != ref_i) {
426 RC_TRACE(0x00080000,
427 ("InvokeDynamic entry@%d name_and_type ref_index change: %d to %d",
428 *merge_cp_length_p, ref_i, new_ref_i));
429 }
430
431 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, bss_idx, new_ref_i);
432 if (scratch_i != *merge_cp_length_p) {
433 // The new entry in *merge_cp_p is at a different index than
434 // the new entry in scratch_cp so we need to map the index values.
435 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
436 }
437 (*merge_cp_length_p)++;
438 } break;
439
440 // At this stage, Class or UnresolvedClass could be here, but not
441 // ClassIndex
442 case JVM_CONSTANT_ClassIndex: // fall through
443
444 // Invalid is used as the tag for the second constant pool entry
445 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
446 // not be seen by itself.
447 case JVM_CONSTANT_Invalid: // fall through
448
449 // At this stage, String could be here, but not StringIndex
450 case JVM_CONSTANT_StringIndex: // fall through
451
452 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be
453 // here
454 case JVM_CONSTANT_UnresolvedClassInError: // fall through
455
456 default:
457 {
458 // leave a breadcrumb
459 jbyte bad_value = scratch_cp->tag_at(scratch_i).value();
460 ShouldNotReachHere();
461 } break;
462 } // end switch tag value
463 } // end append_entry()
464
465
466 int VM_RedefineClasses::find_or_append_indirect_entry(constantPoolHandle scratch_cp,
467 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
468
469 int new_ref_i = ref_i;
470 bool match = (ref_i < *merge_cp_length_p) &&
471 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i, THREAD);
472
473 if (!match) {
474 // forward reference in *merge_cp_p or not a direct match
475 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p, THREAD);
476 if (found_i != 0) {
477 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree");
478 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry.
479 new_ref_i = found_i;
480 map_index(scratch_cp, ref_i, found_i);
481 } else {
482 // no match found so we have to append this entry to *merge_cp_p
483 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p, THREAD);
484 // The above call to append_entry() can only append one entry
485 // so the post call query of *merge_cp_length_p is only for
486 // the sake of consistency.
487 new_ref_i = *merge_cp_length_p - 1;
488 }
489 }
490
491 return new_ref_i;
492 } // end find_or_append_indirect_entry()
493
494
495 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions(
496 instanceKlassHandle the_class,
497 instanceKlassHandle scratch_class) {
498 int i;
499
500 // Check superclasses, or rather their names, since superclasses themselves can be
501 // requested to replace.
502 // Check for NULL superclass first since this might be java.lang.Object
503 if (the_class->super() != scratch_class->super() &&
504 (the_class->super() == NULL || scratch_class->super() == NULL ||
505 the_class->super()->name() !=
506 scratch_class->super()->name())) {
507 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
508 }
509
510 // Check if the number, names and order of directly implemented interfaces are the same.
511 // I think in principle we should just check if the sets of names of directly implemented
512 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the
513 // .java file, also changes in .class file) should not matter. However, comparing sets is
514 // technically a bit more difficult, and, more importantly, I am not sure at present that the
515 // order of interfaces does not matter on the implementation level, i.e. that the VM does not
516 // rely on it somewhere.
517 Array<Klass*>* k_interfaces = the_class->local_interfaces();
518 Array<Klass*>* k_new_interfaces = scratch_class->local_interfaces();
519 int n_intfs = k_interfaces->length();
520 if (n_intfs != k_new_interfaces->length()) {
521 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
522 }
523 for (i = 0; i < n_intfs; i++) {
524 if (k_interfaces->at(i)->name() !=
525 k_new_interfaces->at(i)->name()) {
526 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
527 }
528 }
529
530 // Check whether class is in the error init state.
531 if (the_class->is_in_error_state()) {
532 // TBD #5057930: special error code is needed in 1.6
533 return JVMTI_ERROR_INVALID_CLASS;
534 }
535
536 // Check whether class modifiers are the same.
537 jushort old_flags = (jushort) the_class->access_flags().get_flags();
538 jushort new_flags = (jushort) scratch_class->access_flags().get_flags();
539 if (old_flags != new_flags) {
540 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED;
541 }
542
543 // Check if the number, names, types and order of fields declared in these classes
544 // are the same.
545 JavaFieldStream old_fs(the_class);
546 JavaFieldStream new_fs(scratch_class);
547 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) {
548 // access
549 old_flags = old_fs.access_flags().as_short();
550 new_flags = new_fs.access_flags().as_short();
551 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) {
552 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
553 }
554 // offset
555 if (old_fs.offset() != new_fs.offset()) {
556 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
557 }
558 // name and signature
559 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index());
560 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index());
561 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index());
562 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index());
563 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) {
564 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
565 }
566 }
567
568 // If both streams aren't done then we have a differing number of
569 // fields.
570 if (!old_fs.done() || !new_fs.done()) {
571 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
572 }
573
574 // Do a parallel walk through the old and new methods. Detect
575 // cases where they match (exist in both), have been added in
576 // the new methods, or have been deleted (exist only in the
577 // old methods). The class file parser places methods in order
578 // by method name, but does not order overloaded methods by
579 // signature. In order to determine what fate befell the methods,
580 // this code places the overloaded new methods that have matching
581 // old methods in the same order as the old methods and places
582 // new overloaded methods at the end of overloaded methods of
583 // that name. The code for this order normalization is adapted
584 // from the algorithm used in InstanceKlass::find_method().
585 // Since we are swapping out of order entries as we find them,
586 // we only have to search forward through the overloaded methods.
587 // Methods which are added and have the same name as an existing
588 // method (but different signature) will be put at the end of
589 // the methods with that name, and the name mismatch code will
590 // handle them.
591 Array<Method*>* k_old_methods(the_class->methods());
592 Array<Method*>* k_new_methods(scratch_class->methods());
593 int n_old_methods = k_old_methods->length();
594 int n_new_methods = k_new_methods->length();
595 Thread* thread = Thread::current();
596
597 int ni = 0;
598 int oi = 0;
599 while (true) {
600 Method* k_old_method;
601 Method* k_new_method;
602 enum { matched, added, deleted, undetermined } method_was = undetermined;
603
604 if (oi >= n_old_methods) {
605 if (ni >= n_new_methods) {
606 break; // we've looked at everything, done
607 }
608 // New method at the end
609 k_new_method = k_new_methods->at(ni);
610 method_was = added;
611 } else if (ni >= n_new_methods) {
612 // Old method, at the end, is deleted
613 k_old_method = k_old_methods->at(oi);
614 method_was = deleted;
615 } else {
616 // There are more methods in both the old and new lists
617 k_old_method = k_old_methods->at(oi);
618 k_new_method = k_new_methods->at(ni);
619 if (k_old_method->name() != k_new_method->name()) {
620 // Methods are sorted by method name, so a mismatch means added
621 // or deleted
622 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) {
623 method_was = added;
624 } else {
625 method_was = deleted;
626 }
627 } else if (k_old_method->signature() == k_new_method->signature()) {
628 // Both the name and signature match
629 method_was = matched;
630 } else {
631 // The name matches, but the signature doesn't, which means we have to
632 // search forward through the new overloaded methods.
633 int nj; // outside the loop for post-loop check
634 for (nj = ni + 1; nj < n_new_methods; nj++) {
635 Method* m = k_new_methods->at(nj);
636 if (k_old_method->name() != m->name()) {
637 // reached another method name so no more overloaded methods
638 method_was = deleted;
639 break;
640 }
641 if (k_old_method->signature() == m->signature()) {
642 // found a match so swap the methods
643 k_new_methods->at_put(ni, m);
644 k_new_methods->at_put(nj, k_new_method);
645 k_new_method = m;
646 method_was = matched;
647 break;
648 }
649 }
650
651 if (nj >= n_new_methods) {
652 // reached the end without a match; so method was deleted
653 method_was = deleted;
654 }
655 }
656 }
657
658 switch (method_was) {
659 case matched:
660 // methods match, be sure modifiers do too
661 old_flags = (jushort) k_old_method->access_flags().get_flags();
662 new_flags = (jushort) k_new_method->access_flags().get_flags();
663 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) {
664 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED;
665 }
666 {
667 u2 new_num = k_new_method->method_idnum();
668 u2 old_num = k_old_method->method_idnum();
669 if (new_num != old_num) {
670 Method* idnum_owner = scratch_class->method_with_idnum(old_num);
671 if (idnum_owner != NULL) {
672 // There is already a method assigned this idnum -- switch them
673 idnum_owner->set_method_idnum(new_num);
674 }
675 k_new_method->set_method_idnum(old_num);
676 if (thread->has_pending_exception()) {
677 return JVMTI_ERROR_OUT_OF_MEMORY;
678 }
679 }
680 }
681 RC_TRACE(0x00008000, ("Method matched: new: %s [%d] == old: %s [%d]",
682 k_new_method->name_and_sig_as_C_string(), ni,
683 k_old_method->name_and_sig_as_C_string(), oi));
684 // advance to next pair of methods
685 ++oi;
686 ++ni;
687 break;
688 case added:
689 // method added, see if it is OK
690 new_flags = (jushort) k_new_method->access_flags().get_flags();
691 if ((new_flags & JVM_ACC_PRIVATE) == 0
692 // hack: private should be treated as final, but alas
693 || (new_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
694 ) {
695 // new methods must be private
696 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
697 }
698 {
699 u2 num = the_class->next_method_idnum();
700 if (num == ConstMethod::UNSET_IDNUM) {
701 // cannot add any more methods
702 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
703 }
704 u2 new_num = k_new_method->method_idnum();
705 Method* idnum_owner = scratch_class->method_with_idnum(num);
706 if (idnum_owner != NULL) {
707 // There is already a method assigned this idnum -- switch them
708 idnum_owner->set_method_idnum(new_num);
709 }
710 k_new_method->set_method_idnum(num);
711 if (thread->has_pending_exception()) {
712 return JVMTI_ERROR_OUT_OF_MEMORY;
713 }
714 }
715 RC_TRACE(0x00008000, ("Method added: new: %s [%d]",
716 k_new_method->name_and_sig_as_C_string(), ni));
717 ++ni; // advance to next new method
718 break;
719 case deleted:
720 // method deleted, see if it is OK
721 old_flags = (jushort) k_old_method->access_flags().get_flags();
722 if ((old_flags & JVM_ACC_PRIVATE) == 0
723 // hack: private should be treated as final, but alas
724 || (old_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
725 ) {
726 // deleted methods must be private
727 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED;
728 }
729 RC_TRACE(0x00008000, ("Method deleted: old: %s [%d]",
730 k_old_method->name_and_sig_as_C_string(), oi));
731 ++oi; // advance to next old method
732 break;
733 default:
734 ShouldNotReachHere();
735 }
736 }
737
738 return JVMTI_ERROR_NONE;
739 }
740
741
742 // Find new constant pool index value for old constant pool index value
743 // by seaching the index map. Returns zero (0) if there is no mapped
744 // value for the old constant pool index.
745 int VM_RedefineClasses::find_new_index(int old_index) {
746 if (_index_map_count == 0) {
747 // map is empty so nothing can be found
748 return 0;
749 }
750
751 if (old_index < 1 || old_index >= _index_map_p->length()) {
752 // The old_index is out of range so it is not mapped. This should
753 // not happen in regular constant pool merging use, but it can
754 // happen if a corrupt annotation is processed.
755 return 0;
756 }
757
758 int value = _index_map_p->at(old_index);
759 if (value == -1) {
760 // the old_index is not mapped
761 return 0;
762 }
763
764 return value;
765 } // end find_new_index()
766
767
768 // Returns true if the current mismatch is due to a resolved/unresolved
769 // class pair. Otherwise, returns false.
770 bool VM_RedefineClasses::is_unresolved_class_mismatch(constantPoolHandle cp1,
771 int index1, constantPoolHandle cp2, int index2) {
772
773 jbyte t1 = cp1->tag_at(index1).value();
774 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) {
775 return false; // wrong entry type; not our special case
776 }
777
778 jbyte t2 = cp2->tag_at(index2).value();
779 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) {
780 return false; // wrong entry type; not our special case
781 }
782
783 if (t1 == t2) {
784 return false; // not a mismatch; not our special case
785 }
786
787 char *s1 = cp1->klass_name_at(index1)->as_C_string();
788 char *s2 = cp2->klass_name_at(index2)->as_C_string();
789 if (strcmp(s1, s2) != 0) {
790 return false; // strings don't match; not our special case
791 }
792
793 return true; // made it through the gauntlet; this is our special case
794 } // end is_unresolved_class_mismatch()
795
796
797 jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) {
798
799 // For consistency allocate memory using os::malloc wrapper.
800 _scratch_classes = (Klass**)
801 os::malloc(sizeof(Klass*) * _class_count, mtClass);
802 if (_scratch_classes == NULL) {
803 return JVMTI_ERROR_OUT_OF_MEMORY;
804 }
805 // Zero initialize the _scratch_classes array.
806 for (int i = 0; i < _class_count; i++) {
807 _scratch_classes[i] = NULL;
808 }
809
810 ResourceMark rm(THREAD);
811
812 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
813 // state can only be NULL if the current thread is exiting which
814 // should not happen since we're trying to do a RedefineClasses
815 guarantee(state != NULL, "exiting thread calling load_new_class_versions");
816 for (int i = 0; i < _class_count; i++) {
817 // Create HandleMark so that any handles created while loading new class
818 // versions are deleted. Constant pools are deallocated while merging
819 // constant pools
820 HandleMark hm(THREAD);
821
822 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass);
823 // classes for primitives cannot be redefined
824 if (!is_modifiable_class(mirror)) {
825 return JVMTI_ERROR_UNMODIFIABLE_CLASS;
826 }
827 Klass* the_class_oop = java_lang_Class::as_Klass(mirror);
828 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
829 Symbol* the_class_sym = the_class->name();
830
831 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
832 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
833 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)",
834 the_class->external_name(), _class_load_kind,
835 os::available_memory() >> 10));
836
837 ClassFileStream st((u1*) _class_defs[i].class_bytes,
838 _class_defs[i].class_byte_count, (char *)"__VM_RedefineClasses__");
839
840 // Parse the stream.
841 Handle the_class_loader(THREAD, the_class->class_loader());
842 Handle protection_domain(THREAD, the_class->protection_domain());
843 // Set redefined class handle in JvmtiThreadState class.
844 // This redefined class is sent to agent event handler for class file
845 // load hook event.
846 state->set_class_being_redefined(&the_class, _class_load_kind);
847
848 Klass* k = SystemDictionary::parse_stream(the_class_sym,
849 the_class_loader,
850 protection_domain,
851 &st,
852 THREAD);
853 // Clear class_being_redefined just to be sure.
854 state->clear_class_being_redefined();
855
856 // TODO: if this is retransform, and nothing changed we can skip it
857
858 instanceKlassHandle scratch_class (THREAD, k);
859
860 // Need to clean up allocated InstanceKlass if there's an error so assign
861 // the result here. Caller deallocates all the scratch classes in case of
862 // an error.
863 _scratch_classes[i] = k;
864
865 if (HAS_PENDING_EXCEPTION) {
866 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
867 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
868 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("parse_stream exception: '%s'",
869 ex_name->as_C_string()));
870 CLEAR_PENDING_EXCEPTION;
871
872 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) {
873 return JVMTI_ERROR_UNSUPPORTED_VERSION;
874 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) {
875 return JVMTI_ERROR_INVALID_CLASS_FORMAT;
876 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) {
877 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION;
878 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
879 // The message will be "XXX (wrong name: YYY)"
880 return JVMTI_ERROR_NAMES_DONT_MATCH;
881 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
882 return JVMTI_ERROR_OUT_OF_MEMORY;
883 } else { // Just in case more exceptions can be thrown..
884 return JVMTI_ERROR_FAILS_VERIFICATION;
885 }
886 }
887
888 // Ensure class is linked before redefine
889 if (!the_class->is_linked()) {
890 the_class->link_class(THREAD);
891 if (HAS_PENDING_EXCEPTION) {
892 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
893 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
894 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("link_class exception: '%s'",
895 ex_name->as_C_string()));
896 CLEAR_PENDING_EXCEPTION;
897 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
898 return JVMTI_ERROR_OUT_OF_MEMORY;
899 } else {
900 return JVMTI_ERROR_INTERNAL;
901 }
902 }
903 }
904
905 // Do the validity checks in compare_and_normalize_class_versions()
906 // before verifying the byte codes. By doing these checks first, we
907 // limit the number of functions that require redirection from
908 // the_class to scratch_class. In particular, we don't have to
909 // modify JNI GetSuperclass() and thus won't change its performance.
910 jvmtiError res = compare_and_normalize_class_versions(the_class,
911 scratch_class);
912 if (res != JVMTI_ERROR_NONE) {
913 return res;
914 }
915
916 // verify what the caller passed us
917 {
918 // The bug 6214132 caused the verification to fail.
919 // Information about the_class and scratch_class is temporarily
920 // recorded into jvmtiThreadState. This data is used to redirect
921 // the_class to scratch_class in the JVM_* functions called by the
922 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed
923 // description.
924 RedefineVerifyMark rvm(&the_class, &scratch_class, state);
925 Verifier::verify(
926 scratch_class, Verifier::ThrowException, true, THREAD);
927 }
928
929 if (HAS_PENDING_EXCEPTION) {
930 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
931 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
932 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
933 ("verify_byte_codes exception: '%s'", ex_name->as_C_string()));
934 CLEAR_PENDING_EXCEPTION;
935 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
936 return JVMTI_ERROR_OUT_OF_MEMORY;
937 } else {
938 // tell the caller the bytecodes are bad
939 return JVMTI_ERROR_FAILS_VERIFICATION;
940 }
941 }
942
943 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD);
944 if (res != JVMTI_ERROR_NONE) {
945 return res;
946 }
947
948 if (VerifyMergedCPBytecodes) {
949 // verify what we have done during constant pool merging
950 {
951 RedefineVerifyMark rvm(&the_class, &scratch_class, state);
952 Verifier::verify(scratch_class, Verifier::ThrowException, true, THREAD);
953 }
954
955 if (HAS_PENDING_EXCEPTION) {
956 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
957 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
958 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
959 ("verify_byte_codes post merge-CP exception: '%s'",
960 ex_name->as_C_string()));
961 CLEAR_PENDING_EXCEPTION;
962 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
963 return JVMTI_ERROR_OUT_OF_MEMORY;
964 } else {
965 // tell the caller that constant pool merging screwed up
966 return JVMTI_ERROR_INTERNAL;
967 }
968 }
969 }
970
971 Rewriter::rewrite(scratch_class, THREAD);
972 if (!HAS_PENDING_EXCEPTION) {
973 scratch_class->link_methods(THREAD);
974 }
975 if (HAS_PENDING_EXCEPTION) {
976 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
977 CLEAR_PENDING_EXCEPTION;
978 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
979 return JVMTI_ERROR_OUT_OF_MEMORY;
980 } else {
981 return JVMTI_ERROR_INTERNAL;
982 }
983 }
984
985 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
986 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
987 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)",
988 the_class->external_name(), os::available_memory() >> 10));
989 }
990
991 return JVMTI_ERROR_NONE;
992 }
993
994
995 // Map old_index to new_index as needed. scratch_cp is only needed
996 // for RC_TRACE() calls.
997 void VM_RedefineClasses::map_index(constantPoolHandle scratch_cp,
998 int old_index, int new_index) {
999 if (find_new_index(old_index) != 0) {
1000 // old_index is already mapped
1001 return;
1002 }
1003
1004 if (old_index == new_index) {
1005 // no mapping is needed
1006 return;
1007 }
1008
1009 _index_map_p->at_put(old_index, new_index);
1010 _index_map_count++;
1011
1012 RC_TRACE(0x00040000, ("mapped tag %d at index %d to %d",
1013 scratch_cp->tag_at(old_index).value(), old_index, new_index));
1014 } // end map_index()
1015
1016
1017 // Merge old_cp and scratch_cp and return the results of the merge via
1018 // merge_cp_p. The number of entries in *merge_cp_p is returned via
1019 // merge_cp_length_p. The entries in old_cp occupy the same locations
1020 // in *merge_cp_p. Also creates a map of indices from entries in
1021 // scratch_cp to the corresponding entry in *merge_cp_p. Index map
1022 // entries are only created for entries in scratch_cp that occupy a
1023 // different location in *merged_cp_p.
1024 bool VM_RedefineClasses::merge_constant_pools(constantPoolHandle old_cp,
1025 constantPoolHandle scratch_cp, constantPoolHandle *merge_cp_p,
1026 int *merge_cp_length_p, TRAPS) {
1027
1028 if (merge_cp_p == NULL) {
1029 assert(false, "caller must provide scratch constantPool");
1030 return false; // robustness
1031 }
1032 if (merge_cp_length_p == NULL) {
1033 assert(false, "caller must provide scratch CP length");
1034 return false; // robustness
1035 }
1036 // Worst case we need old_cp->length() + scratch_cp()->length(),
1037 // but the caller might be smart so make sure we have at least
1038 // the minimum.
1039 if ((*merge_cp_p)->length() < old_cp->length()) {
1040 assert(false, "merge area too small");
1041 return false; // robustness
1042 }
1043
1044 RC_TRACE_WITH_THREAD(0x00010000, THREAD,
1045 ("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(),
1046 scratch_cp->length()));
1047
1048 {
1049 // Pass 0:
1050 // The old_cp is copied to *merge_cp_p; this means that any code
1051 // using old_cp does not have to change. This work looks like a
1052 // perfect fit for ConstantPool*::copy_cp_to(), but we need to
1053 // handle one special case:
1054 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass
1055 // This will make verification happy.
1056
1057 int old_i; // index into old_cp
1058
1059 // index zero (0) is not used in constantPools
1060 for (old_i = 1; old_i < old_cp->length(); old_i++) {
1061 // leave debugging crumb
1062 jbyte old_tag = old_cp->tag_at(old_i).value();
1063 switch (old_tag) {
1064 case JVM_CONSTANT_Class:
1065 case JVM_CONSTANT_UnresolvedClass:
1066 // revert the copy to JVM_CONSTANT_UnresolvedClass
1067 // May be resolving while calling this so do the same for
1068 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition)
1069 (*merge_cp_p)->unresolved_klass_at_put(old_i,
1070 old_cp->klass_name_at(old_i));
1071 break;
1072
1073 case JVM_CONSTANT_Double:
1074 case JVM_CONSTANT_Long:
1075 // just copy the entry to *merge_cp_p, but double and long take
1076 // two constant pool entries
1077 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1078 old_i++;
1079 break;
1080
1081 default:
1082 // just copy the entry to *merge_cp_p
1083 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1084 break;
1085 }
1086 } // end for each old_cp entry
1087
1088 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_0);
1089
1090 // We don't need to sanity check that *merge_cp_length_p is within
1091 // *merge_cp_p bounds since we have the minimum on-entry check above.
1092 (*merge_cp_length_p) = old_i;
1093 }
1094
1095 // merge_cp_len should be the same as old_cp->length() at this point
1096 // so this trace message is really a "warm-and-breathing" message.
1097 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1098 ("after pass 0: merge_cp_len=%d", *merge_cp_length_p));
1099
1100 int scratch_i; // index into scratch_cp
1101 {
1102 // Pass 1a:
1103 // Compare scratch_cp entries to the old_cp entries that we have
1104 // already copied to *merge_cp_p. In this pass, we are eliminating
1105 // exact duplicates (matching entry at same index) so we only
1106 // compare entries in the common indice range.
1107 int increment = 1;
1108 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length());
1109 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) {
1110 switch (scratch_cp->tag_at(scratch_i).value()) {
1111 case JVM_CONSTANT_Double:
1112 case JVM_CONSTANT_Long:
1113 // double and long take two constant pool entries
1114 increment = 2;
1115 break;
1116
1117 default:
1118 increment = 1;
1119 break;
1120 }
1121
1122 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p,
1123 scratch_i, CHECK_0);
1124 if (match) {
1125 // found a match at the same index so nothing more to do
1126 continue;
1127 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i,
1128 *merge_cp_p, scratch_i)) {
1129 // The mismatch in compare_entry_to() above is because of a
1130 // resolved versus unresolved class entry at the same index
1131 // with the same string value. Since Pass 0 reverted any
1132 // class entries to unresolved class entries in *merge_cp_p,
1133 // we go with the unresolved class entry.
1134 continue;
1135 }
1136
1137 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p,
1138 CHECK_0);
1139 if (found_i != 0) {
1140 guarantee(found_i != scratch_i,
1141 "compare_entry_to() and find_matching_entry() do not agree");
1142
1143 // Found a matching entry somewhere else in *merge_cp_p so
1144 // just need a mapping entry.
1145 map_index(scratch_cp, scratch_i, found_i);
1146 continue;
1147 }
1148
1149 // The find_matching_entry() call above could fail to find a match
1150 // due to a resolved versus unresolved class or string entry situation
1151 // like we solved above with the is_unresolved_*_mismatch() calls.
1152 // However, we would have to call is_unresolved_*_mismatch() over
1153 // all of *merge_cp_p (potentially) and that doesn't seem to be
1154 // worth the time.
1155
1156 // No match found so we have to append this entry and any unique
1157 // referenced entries to *merge_cp_p.
1158 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1159 CHECK_0);
1160 }
1161 }
1162
1163 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1164 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1165 *merge_cp_length_p, scratch_i, _index_map_count));
1166
1167 if (scratch_i < scratch_cp->length()) {
1168 // Pass 1b:
1169 // old_cp is smaller than scratch_cp so there are entries in
1170 // scratch_cp that we have not yet processed. We take care of
1171 // those now.
1172 int increment = 1;
1173 for (; scratch_i < scratch_cp->length(); scratch_i += increment) {
1174 switch (scratch_cp->tag_at(scratch_i).value()) {
1175 case JVM_CONSTANT_Double:
1176 case JVM_CONSTANT_Long:
1177 // double and long take two constant pool entries
1178 increment = 2;
1179 break;
1180
1181 default:
1182 increment = 1;
1183 break;
1184 }
1185
1186 int found_i =
1187 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0);
1188 if (found_i != 0) {
1189 // Found a matching entry somewhere else in *merge_cp_p so
1190 // just need a mapping entry.
1191 map_index(scratch_cp, scratch_i, found_i);
1192 continue;
1193 }
1194
1195 // No match found so we have to append this entry and any unique
1196 // referenced entries to *merge_cp_p.
1197 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1198 CHECK_0);
1199 }
1200
1201 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1202 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1203 *merge_cp_length_p, scratch_i, _index_map_count));
1204 }
1205
1206 return true;
1207 } // end merge_constant_pools()
1208
1209
1210 // Scoped object to clean up the constant pool(s) created for merging
1211 class MergeCPCleaner {
1212 ClassLoaderData* _loader_data;
1213 ConstantPool* _cp;
1214 ConstantPool* _scratch_cp;
1215 public:
1216 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) :
1217 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {}
1218 ~MergeCPCleaner() {
1219 _loader_data->add_to_deallocate_list(_cp);
1220 if (_scratch_cp != NULL) {
1221 _loader_data->add_to_deallocate_list(_scratch_cp);
1222 }
1223 }
1224 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; }
1225 };
1226
1227 // Merge constant pools between the_class and scratch_class and
1228 // potentially rewrite bytecodes in scratch_class to use the merged
1229 // constant pool.
1230 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite(
1231 instanceKlassHandle the_class, instanceKlassHandle scratch_class,
1232 TRAPS) {
1233 // worst case merged constant pool length is old and new combined
1234 int merge_cp_length = the_class->constants()->length()
1235 + scratch_class->constants()->length();
1236
1237 // Constant pools are not easily reused so we allocate a new one
1238 // each time.
1239 // merge_cp is created unsafe for concurrent GC processing. It
1240 // should be marked safe before discarding it. Even though
1241 // garbage, if it crosses a card boundary, it may be scanned
1242 // in order to find the start of the first complete object on the card.
1243 ClassLoaderData* loader_data = the_class->class_loader_data();
1244 ConstantPool* merge_cp_oop =
1245 ConstantPool::allocate(loader_data,
1246 merge_cp_length,
1247 THREAD);
1248 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop);
1249
1250 HandleMark hm(THREAD); // make sure handles are cleared before
1251 // MergeCPCleaner clears out merge_cp_oop
1252 constantPoolHandle merge_cp(THREAD, merge_cp_oop);
1253
1254 // Get constants() from the old class because it could have been rewritten
1255 // while we were at a safepoint allocating a new constant pool.
1256 constantPoolHandle old_cp(THREAD, the_class->constants());
1257 constantPoolHandle scratch_cp(THREAD, scratch_class->constants());
1258
1259 // If the length changed, the class was redefined out from under us. Return
1260 // an error.
1261 if (merge_cp_length != the_class->constants()->length()
1262 + scratch_class->constants()->length()) {
1263 return JVMTI_ERROR_INTERNAL;
1264 }
1265
1266 // Update the version number of the constant pool
1267 merge_cp->increment_and_save_version(old_cp->version());
1268
1269 ResourceMark rm(THREAD);
1270 _index_map_count = 0;
1271 _index_map_p = new intArray(scratch_cp->length(), -1);
1272
1273 // reference to the cp holder is needed for copy_operands()
1274 merge_cp->set_pool_holder(scratch_class());
1275 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp,
1276 &merge_cp_length, THREAD);
1277 merge_cp->set_pool_holder(NULL);
1278
1279 if (!result) {
1280 // The merge can fail due to memory allocation failure or due
1281 // to robustness checks.
1282 return JVMTI_ERROR_INTERNAL;
1283 }
1284
1285 RC_TRACE_WITH_THREAD(0x00010000, THREAD,
1286 ("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count));
1287
1288 if (_index_map_count == 0) {
1289 // there is nothing to map between the new and merged constant pools
1290
1291 if (old_cp->length() == scratch_cp->length()) {
1292 // The old and new constant pools are the same length and the
1293 // index map is empty. This means that the three constant pools
1294 // are equivalent (but not the same). Unfortunately, the new
1295 // constant pool has not gone through link resolution nor have
1296 // the new class bytecodes gone through constant pool cache
1297 // rewriting so we can't use the old constant pool with the new
1298 // class.
1299
1300 // toss the merged constant pool at return
1301 } else if (old_cp->length() < scratch_cp->length()) {
1302 // The old constant pool has fewer entries than the new constant
1303 // pool and the index map is empty. This means the new constant
1304 // pool is a superset of the old constant pool. However, the old
1305 // class bytecodes have already gone through constant pool cache
1306 // rewriting so we can't use the new constant pool with the old
1307 // class.
1308
1309 // toss the merged constant pool at return
1310 } else {
1311 // The old constant pool has more entries than the new constant
1312 // pool and the index map is empty. This means that both the old
1313 // and merged constant pools are supersets of the new constant
1314 // pool.
1315
1316 // Replace the new constant pool with a shrunken copy of the
1317 // merged constant pool
1318 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, THREAD);
1319 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1320 // It can't be cleaned up while there are handles to it.
1321 cp_cleaner.add_scratch_cp(scratch_cp());
1322 }
1323 } else {
1324 if (RC_TRACE_ENABLED(0x00040000)) {
1325 // don't want to loop unless we are tracing
1326 int count = 0;
1327 for (int i = 1; i < _index_map_p->length(); i++) {
1328 int value = _index_map_p->at(i);
1329
1330 if (value != -1) {
1331 RC_TRACE_WITH_THREAD(0x00040000, THREAD,
1332 ("index_map[%d]: old=%d new=%d", count, i, value));
1333 count++;
1334 }
1335 }
1336 }
1337
1338 // We have entries mapped between the new and merged constant pools
1339 // so we have to rewrite some constant pool references.
1340 if (!rewrite_cp_refs(scratch_class, THREAD)) {
1341 return JVMTI_ERROR_INTERNAL;
1342 }
1343
1344 // Replace the new constant pool with a shrunken copy of the
1345 // merged constant pool so now the rewritten bytecodes have
1346 // valid references; the previous new constant pool will get
1347 // GCed.
1348 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, THREAD);
1349 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1350 // It can't be cleaned up while there are handles to it.
1351 cp_cleaner.add_scratch_cp(scratch_cp());
1352 }
1353
1354 return JVMTI_ERROR_NONE;
1355 } // end merge_cp_and_rewrite()
1356
1357
1358 // Rewrite constant pool references in klass scratch_class.
1359 bool VM_RedefineClasses::rewrite_cp_refs(instanceKlassHandle scratch_class,
1360 TRAPS) {
1361
1362 // rewrite constant pool references in the methods:
1363 if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) {
1364 // propagate failure back to caller
1365 return false;
1366 }
1367
1368 // rewrite constant pool references in the class_annotations:
1369 if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) {
1370 // propagate failure back to caller
1371 return false;
1372 }
1373
1374 // rewrite constant pool references in the fields_annotations:
1375 if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) {
1376 // propagate failure back to caller
1377 return false;
1378 }
1379
1380 // rewrite constant pool references in the methods_annotations:
1381 if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) {
1382 // propagate failure back to caller
1383 return false;
1384 }
1385
1386 // rewrite constant pool references in the methods_parameter_annotations:
1387 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class,
1388 THREAD)) {
1389 // propagate failure back to caller
1390 return false;
1391 }
1392
1393 // rewrite constant pool references in the methods_default_annotations:
1394 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class,
1395 THREAD)) {
1396 // propagate failure back to caller
1397 return false;
1398 }
1399
1400 return true;
1401 } // end rewrite_cp_refs()
1402
1403
1404 // Rewrite constant pool references in the methods.
1405 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(
1406 instanceKlassHandle scratch_class, TRAPS) {
1407
1408 Array<Method*>* methods = scratch_class->methods();
1409
1410 if (methods == NULL || methods->length() == 0) {
1411 // no methods so nothing to do
1412 return true;
1413 }
1414
1415 // rewrite constant pool references in the methods:
1416 for (int i = methods->length() - 1; i >= 0; i--) {
1417 methodHandle method(THREAD, methods->at(i));
1418 methodHandle new_method;
1419 rewrite_cp_refs_in_method(method, &new_method, CHECK_false);
1420 if (!new_method.is_null()) {
1421 // the method has been replaced so save the new method version
1422 methods->at_put(i, new_method());
1423 }
1424 }
1425
1426 return true;
1427 }
1428
1429
1430 // Rewrite constant pool references in the specific method. This code
1431 // was adapted from Rewriter::rewrite_method().
1432 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method,
1433 methodHandle *new_method_p, TRAPS) {
1434
1435 *new_method_p = methodHandle(); // default is no new method
1436
1437 // We cache a pointer to the bytecodes here in code_base. If GC
1438 // moves the Method*, then the bytecodes will also move which
1439 // will likely cause a crash. We create a No_Safepoint_Verifier
1440 // object to detect whether we pass a possible safepoint in this
1441 // code block.
1442 No_Safepoint_Verifier nsv;
1443
1444 // Bytecodes and their length
1445 address code_base = method->code_base();
1446 int code_length = method->code_size();
1447
1448 int bc_length;
1449 for (int bci = 0; bci < code_length; bci += bc_length) {
1450 address bcp = code_base + bci;
1451 Bytecodes::Code c = (Bytecodes::Code)(*bcp);
1452
1453 bc_length = Bytecodes::length_for(c);
1454 if (bc_length == 0) {
1455 // More complicated bytecodes report a length of zero so
1456 // we have to try again a slightly different way.
1457 bc_length = Bytecodes::length_at(method(), bcp);
1458 }
1459
1460 assert(bc_length != 0, "impossible bytecode length");
1461
1462 switch (c) {
1463 case Bytecodes::_ldc:
1464 {
1465 int cp_index = *(bcp + 1);
1466 int new_index = find_new_index(cp_index);
1467
1468 if (StressLdcRewrite && new_index == 0) {
1469 // If we are stressing ldc -> ldc_w rewriting, then we
1470 // always need a new_index value.
1471 new_index = cp_index;
1472 }
1473 if (new_index != 0) {
1474 // the original index is mapped so we have more work to do
1475 if (!StressLdcRewrite && new_index <= max_jubyte) {
1476 // The new value can still use ldc instead of ldc_w
1477 // unless we are trying to stress ldc -> ldc_w rewriting
1478 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1479 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
1480 bcp, cp_index, new_index));
1481 *(bcp + 1) = new_index;
1482 } else {
1483 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1484 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d",
1485 Bytecodes::name(c), bcp, cp_index, new_index));
1486 // the new value needs ldc_w instead of ldc
1487 u_char inst_buffer[4]; // max instruction size is 4 bytes
1488 bcp = (address)inst_buffer;
1489 // construct new instruction sequence
1490 *bcp = Bytecodes::_ldc_w;
1491 bcp++;
1492 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w.
1493 // See comment below for difference between put_Java_u2()
1494 // and put_native_u2().
1495 Bytes::put_Java_u2(bcp, new_index);
1496
1497 Relocator rc(method, NULL /* no RelocatorListener needed */);
1498 methodHandle m;
1499 {
1500 Pause_No_Safepoint_Verifier pnsv(&nsv);
1501
1502 // ldc is 2 bytes and ldc_w is 3 bytes
1503 m = rc.insert_space_at(bci, 3, inst_buffer, THREAD);
1504 if (m.is_null() || HAS_PENDING_EXCEPTION) {
1505 guarantee(false, "insert_space_at() failed");
1506 }
1507 }
1508
1509 // return the new method so that the caller can update
1510 // the containing class
1511 *new_method_p = method = m;
1512 // switch our bytecode processing loop from the old method
1513 // to the new method
1514 code_base = method->code_base();
1515 code_length = method->code_size();
1516 bcp = code_base + bci;
1517 c = (Bytecodes::Code)(*bcp);
1518 bc_length = Bytecodes::length_for(c);
1519 assert(bc_length != 0, "sanity check");
1520 } // end we need ldc_w instead of ldc
1521 } // end if there is a mapped index
1522 } break;
1523
1524 // these bytecodes have a two-byte constant pool index
1525 case Bytecodes::_anewarray : // fall through
1526 case Bytecodes::_checkcast : // fall through
1527 case Bytecodes::_getfield : // fall through
1528 case Bytecodes::_getstatic : // fall through
1529 case Bytecodes::_instanceof : // fall through
1530 case Bytecodes::_invokedynamic : // fall through
1531 case Bytecodes::_invokeinterface: // fall through
1532 case Bytecodes::_invokespecial : // fall through
1533 case Bytecodes::_invokestatic : // fall through
1534 case Bytecodes::_invokevirtual : // fall through
1535 case Bytecodes::_ldc_w : // fall through
1536 case Bytecodes::_ldc2_w : // fall through
1537 case Bytecodes::_multianewarray : // fall through
1538 case Bytecodes::_new : // fall through
1539 case Bytecodes::_putfield : // fall through
1540 case Bytecodes::_putstatic :
1541 {
1542 address p = bcp + 1;
1543 int cp_index = Bytes::get_Java_u2(p);
1544 int new_index = find_new_index(cp_index);
1545 if (new_index != 0) {
1546 // the original index is mapped so update w/ new value
1547 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1548 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
1549 bcp, cp_index, new_index));
1550 // Rewriter::rewrite_method() uses put_native_u2() in this
1551 // situation because it is reusing the constant pool index
1552 // location for a native index into the ConstantPoolCache.
1553 // Since we are updating the constant pool index prior to
1554 // verification and ConstantPoolCache initialization, we
1555 // need to keep the new index in Java byte order.
1556 Bytes::put_Java_u2(p, new_index);
1557 }
1558 } break;
1559 }
1560 } // end for each bytecode
1561
1562 // We also need to rewrite the parameter name indexes, if there is
1563 // method parameter data present
1564 if(method->has_method_parameters()) {
1565 const int len = method->method_parameters_length();
1566 MethodParametersElement* elem = method->method_parameters_start();
1567
1568 for (int i = 0; i < len; i++) {
1569 const u2 cp_index = elem[i].name_cp_index;
1570 elem[i].name_cp_index = find_new_index(cp_index);
1571 }
1572 }
1573 } // end rewrite_cp_refs_in_method()
1574
1575
1576 // Rewrite constant pool references in the class_annotations field.
1577 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(
1578 instanceKlassHandle scratch_class, TRAPS) {
1579
1580 AnnotationArray* class_annotations = scratch_class->class_annotations();
1581 if (class_annotations == NULL || class_annotations->length() == 0) {
1582 // no class_annotations so nothing to do
1583 return true;
1584 }
1585
1586 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1587 ("class_annotations length=%d", class_annotations->length()));
1588
1589 int byte_i = 0; // byte index into class_annotations
1590 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i,
1591 THREAD);
1592 }
1593
1594
1595 // Rewrite constant pool references in an annotations typeArray. This
1596 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute
1597 // that is described in section 4.8.15 of the 2nd-edition of the VM spec:
1598 //
1599 // annotations_typeArray {
1600 // u2 num_annotations;
1601 // annotation annotations[num_annotations];
1602 // }
1603 //
1604 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray(
1605 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1606
1607 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1608 // not enough room for num_annotations field
1609 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1610 ("length() is too small for num_annotations field"));
1611 return false;
1612 }
1613
1614 u2 num_annotations = Bytes::get_Java_u2((address)
1615 annotations_typeArray->adr_at(byte_i_ref));
1616 byte_i_ref += 2;
1617
1618 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1619 ("num_annotations=%d", num_annotations));
1620
1621 int calc_num_annotations = 0;
1622 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
1623 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
1624 byte_i_ref, THREAD)) {
1625 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1626 ("bad annotation_struct at %d", calc_num_annotations));
1627 // propagate failure back to caller
1628 return false;
1629 }
1630 }
1631 assert(num_annotations == calc_num_annotations, "sanity check");
1632
1633 return true;
1634 } // end rewrite_cp_refs_in_annotations_typeArray()
1635
1636
1637 // Rewrite constant pool references in the annotation struct portion of
1638 // an annotations_typeArray. This "structure" is from section 4.8.15 of
1639 // the 2nd-edition of the VM spec:
1640 //
1641 // struct annotation {
1642 // u2 type_index;
1643 // u2 num_element_value_pairs;
1644 // {
1645 // u2 element_name_index;
1646 // element_value value;
1647 // } element_value_pairs[num_element_value_pairs];
1648 // }
1649 //
1650 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct(
1651 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1652 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) {
1653 // not enough room for smallest annotation_struct
1654 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1655 ("length() is too small for annotation_struct"));
1656 return false;
1657 }
1658
1659 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray,
1660 byte_i_ref, "mapped old type_index=%d", THREAD);
1661
1662 u2 num_element_value_pairs = Bytes::get_Java_u2((address)
1663 annotations_typeArray->adr_at(byte_i_ref));
1664 byte_i_ref += 2;
1665
1666 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1667 ("type_index=%d num_element_value_pairs=%d", type_index,
1668 num_element_value_pairs));
1669
1670 int calc_num_element_value_pairs = 0;
1671 for (; calc_num_element_value_pairs < num_element_value_pairs;
1672 calc_num_element_value_pairs++) {
1673 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1674 // not enough room for another element_name_index, let alone
1675 // the rest of another component
1676 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1677 ("length() is too small for element_name_index"));
1678 return false;
1679 }
1680
1681 u2 element_name_index = rewrite_cp_ref_in_annotation_data(
1682 annotations_typeArray, byte_i_ref,
1683 "mapped old element_name_index=%d", THREAD);
1684
1685 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1686 ("element_name_index=%d", element_name_index));
1687
1688 if (!rewrite_cp_refs_in_element_value(annotations_typeArray,
1689 byte_i_ref, THREAD)) {
1690 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1691 ("bad element_value at %d", calc_num_element_value_pairs));
1692 // propagate failure back to caller
1693 return false;
1694 }
1695 } // end for each component
1696 assert(num_element_value_pairs == calc_num_element_value_pairs,
1697 "sanity check");
1698
1699 return true;
1700 } // end rewrite_cp_refs_in_annotation_struct()
1701
1702
1703 // Rewrite a constant pool reference at the current position in
1704 // annotations_typeArray if needed. Returns the original constant
1705 // pool reference if a rewrite was not needed or the new constant
1706 // pool reference if a rewrite was needed.
1707 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data(
1708 AnnotationArray* annotations_typeArray, int &byte_i_ref,
1709 const char * trace_mesg, TRAPS) {
1710
1711 address cp_index_addr = (address)
1712 annotations_typeArray->adr_at(byte_i_ref);
1713 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr);
1714 u2 new_cp_index = find_new_index(old_cp_index);
1715 if (new_cp_index != 0) {
1716 RC_TRACE_WITH_THREAD(0x02000000, THREAD, (trace_mesg, old_cp_index));
1717 Bytes::put_Java_u2(cp_index_addr, new_cp_index);
1718 old_cp_index = new_cp_index;
1719 }
1720 byte_i_ref += 2;
1721 return old_cp_index;
1722 }
1723
1724
1725 // Rewrite constant pool references in the element_value portion of an
1726 // annotations_typeArray. This "structure" is from section 4.8.15.1 of
1727 // the 2nd-edition of the VM spec:
1728 //
1729 // struct element_value {
1730 // u1 tag;
1731 // union {
1732 // u2 const_value_index;
1733 // {
1734 // u2 type_name_index;
1735 // u2 const_name_index;
1736 // } enum_const_value;
1737 // u2 class_info_index;
1738 // annotation annotation_value;
1739 // struct {
1740 // u2 num_values;
1741 // element_value values[num_values];
1742 // } array_value;
1743 // } value;
1744 // }
1745 //
1746 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value(
1747 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1748
1749 if ((byte_i_ref + 1) > annotations_typeArray->length()) {
1750 // not enough room for a tag let alone the rest of an element_value
1751 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1752 ("length() is too small for a tag"));
1753 return false;
1754 }
1755
1756 u1 tag = annotations_typeArray->at(byte_i_ref);
1757 byte_i_ref++;
1758 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("tag='%c'", tag));
1759
1760 switch (tag) {
1761 // These BaseType tag values are from Table 4.2 in VM spec:
1762 case 'B': // byte
1763 case 'C': // char
1764 case 'D': // double
1765 case 'F': // float
1766 case 'I': // int
1767 case 'J': // long
1768 case 'S': // short
1769 case 'Z': // boolean
1770
1771 // The remaining tag values are from Table 4.8 in the 2nd-edition of
1772 // the VM spec:
1773 case 's':
1774 {
1775 // For the above tag values (including the BaseType values),
1776 // value.const_value_index is right union field.
1777
1778 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1779 // not enough room for a const_value_index
1780 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1781 ("length() is too small for a const_value_index"));
1782 return false;
1783 }
1784
1785 u2 const_value_index = rewrite_cp_ref_in_annotation_data(
1786 annotations_typeArray, byte_i_ref,
1787 "mapped old const_value_index=%d", THREAD);
1788
1789 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1790 ("const_value_index=%d", const_value_index));
1791 } break;
1792
1793 case 'e':
1794 {
1795 // for the above tag value, value.enum_const_value is right union field
1796
1797 if ((byte_i_ref + 4) > annotations_typeArray->length()) {
1798 // not enough room for a enum_const_value
1799 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1800 ("length() is too small for a enum_const_value"));
1801 return false;
1802 }
1803
1804 u2 type_name_index = rewrite_cp_ref_in_annotation_data(
1805 annotations_typeArray, byte_i_ref,
1806 "mapped old type_name_index=%d", THREAD);
1807
1808 u2 const_name_index = rewrite_cp_ref_in_annotation_data(
1809 annotations_typeArray, byte_i_ref,
1810 "mapped old const_name_index=%d", THREAD);
1811
1812 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1813 ("type_name_index=%d const_name_index=%d", type_name_index,
1814 const_name_index));
1815 } break;
1816
1817 case 'c':
1818 {
1819 // for the above tag value, value.class_info_index is right union field
1820
1821 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1822 // not enough room for a class_info_index
1823 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1824 ("length() is too small for a class_info_index"));
1825 return false;
1826 }
1827
1828 u2 class_info_index = rewrite_cp_ref_in_annotation_data(
1829 annotations_typeArray, byte_i_ref,
1830 "mapped old class_info_index=%d", THREAD);
1831
1832 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1833 ("class_info_index=%d", class_info_index));
1834 } break;
1835
1836 case '@':
1837 // For the above tag value, value.attr_value is the right union
1838 // field. This is a nested annotation.
1839 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
1840 byte_i_ref, THREAD)) {
1841 // propagate failure back to caller
1842 return false;
1843 }
1844 break;
1845
1846 case '[':
1847 {
1848 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1849 // not enough room for a num_values field
1850 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1851 ("length() is too small for a num_values field"));
1852 return false;
1853 }
1854
1855 // For the above tag value, value.array_value is the right union
1856 // field. This is an array of nested element_value.
1857 u2 num_values = Bytes::get_Java_u2((address)
1858 annotations_typeArray->adr_at(byte_i_ref));
1859 byte_i_ref += 2;
1860 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("num_values=%d", num_values));
1861
1862 int calc_num_values = 0;
1863 for (; calc_num_values < num_values; calc_num_values++) {
1864 if (!rewrite_cp_refs_in_element_value(
1865 annotations_typeArray, byte_i_ref, THREAD)) {
1866 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1867 ("bad nested element_value at %d", calc_num_values));
1868 // propagate failure back to caller
1869 return false;
1870 }
1871 }
1872 assert(num_values == calc_num_values, "sanity check");
1873 } break;
1874
1875 default:
1876 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("bad tag=0x%x", tag));
1877 return false;
1878 } // end decode tag field
1879
1880 return true;
1881 } // end rewrite_cp_refs_in_element_value()
1882
1883
1884 // Rewrite constant pool references in a fields_annotations field.
1885 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations(
1886 instanceKlassHandle scratch_class, TRAPS) {
1887
1888 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations();
1889
1890 if (fields_annotations == NULL || fields_annotations->length() == 0) {
1891 // no fields_annotations so nothing to do
1892 return true;
1893 }
1894
1895 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1896 ("fields_annotations length=%d", fields_annotations->length()));
1897
1898 for (int i = 0; i < fields_annotations->length(); i++) {
1899 AnnotationArray* field_annotations = fields_annotations->at(i);
1900 if (field_annotations == NULL || field_annotations->length() == 0) {
1901 // this field does not have any annotations so skip it
1902 continue;
1903 }
1904
1905 int byte_i = 0; // byte index into field_annotations
1906 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i,
1907 THREAD)) {
1908 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1909 ("bad field_annotations at %d", i));
1910 // propagate failure back to caller
1911 return false;
1912 }
1913 }
1914
1915 return true;
1916 } // end rewrite_cp_refs_in_fields_annotations()
1917
1918
1919 // Rewrite constant pool references in a methods_annotations field.
1920 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations(
1921 instanceKlassHandle scratch_class, TRAPS) {
1922
1923 for (int i = 0; i < scratch_class->methods()->length(); i++) {
1924 Method* m = scratch_class->methods()->at(i);
1925 AnnotationArray* method_annotations = m->constMethod()->method_annotations();
1926
1927 if (method_annotations == NULL || method_annotations->length() == 0) {
1928 // this method does not have any annotations so skip it
1929 continue;
1930 }
1931
1932 int byte_i = 0; // byte index into method_annotations
1933 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i,
1934 THREAD)) {
1935 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1936 ("bad method_annotations at %d", i));
1937 // propagate failure back to caller
1938 return false;
1939 }
1940 }
1941
1942 return true;
1943 } // end rewrite_cp_refs_in_methods_annotations()
1944
1945
1946 // Rewrite constant pool references in a methods_parameter_annotations
1947 // field. This "structure" is adapted from the
1948 // RuntimeVisibleParameterAnnotations_attribute described in section
1949 // 4.8.17 of the 2nd-edition of the VM spec:
1950 //
1951 // methods_parameter_annotations_typeArray {
1952 // u1 num_parameters;
1953 // {
1954 // u2 num_annotations;
1955 // annotation annotations[num_annotations];
1956 // } parameter_annotations[num_parameters];
1957 // }
1958 //
1959 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations(
1960 instanceKlassHandle scratch_class, TRAPS) {
1961
1962 for (int i = 0; i < scratch_class->methods()->length(); i++) {
1963 Method* m = scratch_class->methods()->at(i);
1964 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations();
1965 if (method_parameter_annotations == NULL
1966 || method_parameter_annotations->length() == 0) {
1967 // this method does not have any parameter annotations so skip it
1968 continue;
1969 }
1970
1971 if (method_parameter_annotations->length() < 1) {
1972 // not enough room for a num_parameters field
1973 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1974 ("length() is too small for a num_parameters field at %d", i));
1975 return false;
1976 }
1977
1978 int byte_i = 0; // byte index into method_parameter_annotations
1979
1980 u1 num_parameters = method_parameter_annotations->at(byte_i);
1981 byte_i++;
1982
1983 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1984 ("num_parameters=%d", num_parameters));
1985
1986 int calc_num_parameters = 0;
1987 for (; calc_num_parameters < num_parameters; calc_num_parameters++) {
1988 if (!rewrite_cp_refs_in_annotations_typeArray(
1989 method_parameter_annotations, byte_i, THREAD)) {
1990 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1991 ("bad method_parameter_annotations at %d", calc_num_parameters));
1992 // propagate failure back to caller
1993 return false;
1994 }
1995 }
1996 assert(num_parameters == calc_num_parameters, "sanity check");
1997 }
1998
1999 return true;
2000 } // end rewrite_cp_refs_in_methods_parameter_annotations()
2001
2002
2003 // Rewrite constant pool references in a methods_default_annotations
2004 // field. This "structure" is adapted from the AnnotationDefault_attribute
2005 // that is described in section 4.8.19 of the 2nd-edition of the VM spec:
2006 //
2007 // methods_default_annotations_typeArray {
2008 // element_value default_value;
2009 // }
2010 //
2011 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations(
2012 instanceKlassHandle scratch_class, TRAPS) {
2013
2014 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2015 Method* m = scratch_class->methods()->at(i);
2016 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations();
2017 if (method_default_annotations == NULL
2018 || method_default_annotations->length() == 0) {
2019 // this method does not have any default annotations so skip it
2020 continue;
2021 }
2022
2023 int byte_i = 0; // byte index into method_default_annotations
2024
2025 if (!rewrite_cp_refs_in_element_value(
2026 method_default_annotations, byte_i, THREAD)) {
2027 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2028 ("bad default element_value at %d", i));
2029 // propagate failure back to caller
2030 return false;
2031 }
2032 }
2033
2034 return true;
2035 } // end rewrite_cp_refs_in_methods_default_annotations()
2036
2037
2038 // Rewrite constant pool references in the method's stackmap table.
2039 // These "structures" are adapted from the StackMapTable_attribute that
2040 // is described in section 4.8.4 of the 6.0 version of the VM spec
2041 // (dated 2005.10.26):
2042 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2043 //
2044 // stack_map {
2045 // u2 number_of_entries;
2046 // stack_map_frame entries[number_of_entries];
2047 // }
2048 //
2049 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table(
2050 methodHandle method, TRAPS) {
2051
2052 if (!method->has_stackmap_table()) {
2053 return;
2054 }
2055
2056 AnnotationArray* stackmap_data = method->stackmap_data();
2057 address stackmap_p = (address)stackmap_data->adr_at(0);
2058 address stackmap_end = stackmap_p + stackmap_data->length();
2059
2060 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries");
2061 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p);
2062 stackmap_p += 2;
2063
2064 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2065 ("number_of_entries=%u", number_of_entries));
2066
2067 // walk through each stack_map_frame
2068 u2 calc_number_of_entries = 0;
2069 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) {
2070 // The stack_map_frame structure is a u1 frame_type followed by
2071 // 0 or more bytes of data:
2072 //
2073 // union stack_map_frame {
2074 // same_frame;
2075 // same_locals_1_stack_item_frame;
2076 // same_locals_1_stack_item_frame_extended;
2077 // chop_frame;
2078 // same_frame_extended;
2079 // append_frame;
2080 // full_frame;
2081 // }
2082
2083 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type");
2084 // The Linux compiler does not like frame_type to be u1 or u2. It
2085 // issues the following warning for the first if-statement below:
2086 //
2087 // "warning: comparison is always true due to limited range of data type"
2088 //
2089 u4 frame_type = *stackmap_p;
2090 stackmap_p++;
2091
2092 // same_frame {
2093 // u1 frame_type = SAME; /* 0-63 */
2094 // }
2095 if (frame_type >= 0 && frame_type <= 63) {
2096 // nothing more to do for same_frame
2097 }
2098
2099 // same_locals_1_stack_item_frame {
2100 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */
2101 // verification_type_info stack[1];
2102 // }
2103 else if (frame_type >= 64 && frame_type <= 127) {
2104 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2105 calc_number_of_entries, frame_type, THREAD);
2106 }
2107
2108 // reserved for future use
2109 else if (frame_type >= 128 && frame_type <= 246) {
2110 // nothing more to do for reserved frame_types
2111 }
2112
2113 // same_locals_1_stack_item_frame_extended {
2114 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */
2115 // u2 offset_delta;
2116 // verification_type_info stack[1];
2117 // }
2118 else if (frame_type == 247) {
2119 stackmap_p += 2;
2120 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2121 calc_number_of_entries, frame_type, THREAD);
2122 }
2123
2124 // chop_frame {
2125 // u1 frame_type = CHOP; /* 248-250 */
2126 // u2 offset_delta;
2127 // }
2128 else if (frame_type >= 248 && frame_type <= 250) {
2129 stackmap_p += 2;
2130 }
2131
2132 // same_frame_extended {
2133 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/
2134 // u2 offset_delta;
2135 // }
2136 else if (frame_type == 251) {
2137 stackmap_p += 2;
2138 }
2139
2140 // append_frame {
2141 // u1 frame_type = APPEND; /* 252-254 */
2142 // u2 offset_delta;
2143 // verification_type_info locals[frame_type - 251];
2144 // }
2145 else if (frame_type >= 252 && frame_type <= 254) {
2146 assert(stackmap_p + 2 <= stackmap_end,
2147 "no room for offset_delta");
2148 stackmap_p += 2;
2149 u1 len = frame_type - 251;
2150 for (u1 i = 0; i < len; i++) {
2151 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2152 calc_number_of_entries, frame_type, THREAD);
2153 }
2154 }
2155
2156 // full_frame {
2157 // u1 frame_type = FULL_FRAME; /* 255 */
2158 // u2 offset_delta;
2159 // u2 number_of_locals;
2160 // verification_type_info locals[number_of_locals];
2161 // u2 number_of_stack_items;
2162 // verification_type_info stack[number_of_stack_items];
2163 // }
2164 else if (frame_type == 255) {
2165 assert(stackmap_p + 2 + 2 <= stackmap_end,
2166 "no room for smallest full_frame");
2167 stackmap_p += 2;
2168
2169 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p);
2170 stackmap_p += 2;
2171
2172 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) {
2173 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2174 calc_number_of_entries, frame_type, THREAD);
2175 }
2176
2177 // Use the largest size for the number_of_stack_items, but only get
2178 // the right number of bytes.
2179 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p);
2180 stackmap_p += 2;
2181
2182 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) {
2183 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2184 calc_number_of_entries, frame_type, THREAD);
2185 }
2186 }
2187 } // end while there is a stack_map_frame
2188 assert(number_of_entries == calc_number_of_entries, "sanity check");
2189 } // end rewrite_cp_refs_in_stack_map_table()
2190
2191
2192 // Rewrite constant pool references in the verification type info
2193 // portion of the method's stackmap table. These "structures" are
2194 // adapted from the StackMapTable_attribute that is described in
2195 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26):
2196 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2197 //
2198 // The verification_type_info structure is a u1 tag followed by 0 or
2199 // more bytes of data:
2200 //
2201 // union verification_type_info {
2202 // Top_variable_info;
2203 // Integer_variable_info;
2204 // Float_variable_info;
2205 // Long_variable_info;
2206 // Double_variable_info;
2207 // Null_variable_info;
2208 // UninitializedThis_variable_info;
2209 // Object_variable_info;
2210 // Uninitialized_variable_info;
2211 // }
2212 //
2213 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info(
2214 address& stackmap_p_ref, address stackmap_end, u2 frame_i,
2215 u1 frame_type, TRAPS) {
2216
2217 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag");
2218 u1 tag = *stackmap_p_ref;
2219 stackmap_p_ref++;
2220
2221 switch (tag) {
2222 // Top_variable_info {
2223 // u1 tag = ITEM_Top; /* 0 */
2224 // }
2225 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top
2226 case 0: // fall through
2227
2228 // Integer_variable_info {
2229 // u1 tag = ITEM_Integer; /* 1 */
2230 // }
2231 case ITEM_Integer: // fall through
2232
2233 // Float_variable_info {
2234 // u1 tag = ITEM_Float; /* 2 */
2235 // }
2236 case ITEM_Float: // fall through
2237
2238 // Double_variable_info {
2239 // u1 tag = ITEM_Double; /* 3 */
2240 // }
2241 case ITEM_Double: // fall through
2242
2243 // Long_variable_info {
2244 // u1 tag = ITEM_Long; /* 4 */
2245 // }
2246 case ITEM_Long: // fall through
2247
2248 // Null_variable_info {
2249 // u1 tag = ITEM_Null; /* 5 */
2250 // }
2251 case ITEM_Null: // fall through
2252
2253 // UninitializedThis_variable_info {
2254 // u1 tag = ITEM_UninitializedThis; /* 6 */
2255 // }
2256 case ITEM_UninitializedThis:
2257 // nothing more to do for the above tag types
2258 break;
2259
2260 // Object_variable_info {
2261 // u1 tag = ITEM_Object; /* 7 */
2262 // u2 cpool_index;
2263 // }
2264 case ITEM_Object:
2265 {
2266 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index");
2267 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref);
2268 u2 new_cp_index = find_new_index(cpool_index);
2269 if (new_cp_index != 0) {
2270 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2271 ("mapped old cpool_index=%d", cpool_index));
2272 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
2273 cpool_index = new_cp_index;
2274 }
2275 stackmap_p_ref += 2;
2276
2277 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2278 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i,
2279 frame_type, cpool_index));
2280 } break;
2281
2282 // Uninitialized_variable_info {
2283 // u1 tag = ITEM_Uninitialized; /* 8 */
2284 // u2 offset;
2285 // }
2286 case ITEM_Uninitialized:
2287 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset");
2288 stackmap_p_ref += 2;
2289 break;
2290
2291 default:
2292 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2293 ("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag));
2294 ShouldNotReachHere();
2295 break;
2296 } // end switch (tag)
2297 } // end rewrite_cp_refs_in_verification_type_info()
2298
2299
2300 // Change the constant pool associated with klass scratch_class to
2301 // scratch_cp. If shrink is true, then scratch_cp_length elements
2302 // are copied from scratch_cp to a smaller constant pool and the
2303 // smaller constant pool is associated with scratch_class.
2304 void VM_RedefineClasses::set_new_constant_pool(
2305 ClassLoaderData* loader_data,
2306 instanceKlassHandle scratch_class, constantPoolHandle scratch_cp,
2307 int scratch_cp_length, TRAPS) {
2308 assert(scratch_cp->length() >= scratch_cp_length, "sanity check");
2309
2310 // scratch_cp is a merged constant pool and has enough space for a
2311 // worst case merge situation. We want to associate the minimum
2312 // sized constant pool with the klass to save space.
2313 constantPoolHandle smaller_cp(THREAD,
2314 ConstantPool::allocate(loader_data, scratch_cp_length, THREAD));
2315
2316 // preserve version() value in the smaller copy
2317 int version = scratch_cp->version();
2318 assert(version != 0, "sanity check");
2319 smaller_cp->set_version(version);
2320
2321 // attach klass to new constant pool
2322 // reference to the cp holder is needed for copy_operands()
2323 smaller_cp->set_pool_holder(scratch_class());
2324
2325 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
2326 scratch_cp = smaller_cp;
2327
2328 // attach new constant pool to klass
2329 scratch_class->set_constants(scratch_cp());
2330
2331 int i; // for portability
2332
2333 // update each field in klass to use new constant pool indices as needed
2334 for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) {
2335 jshort cur_index = fs.name_index();
2336 jshort new_index = find_new_index(cur_index);
2337 if (new_index != 0) {
2338 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2339 ("field-name_index change: %d to %d", cur_index, new_index));
2340 fs.set_name_index(new_index);
2341 }
2342 cur_index = fs.signature_index();
2343 new_index = find_new_index(cur_index);
2344 if (new_index != 0) {
2345 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2346 ("field-signature_index change: %d to %d", cur_index, new_index));
2347 fs.set_signature_index(new_index);
2348 }
2349 cur_index = fs.initval_index();
2350 new_index = find_new_index(cur_index);
2351 if (new_index != 0) {
2352 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2353 ("field-initval_index change: %d to %d", cur_index, new_index));
2354 fs.set_initval_index(new_index);
2355 }
2356 cur_index = fs.generic_signature_index();
2357 new_index = find_new_index(cur_index);
2358 if (new_index != 0) {
2359 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2360 ("field-generic_signature change: %d to %d", cur_index, new_index));
2361 fs.set_generic_signature_index(new_index);
2362 }
2363 } // end for each field
2364
2365 // Update constant pool indices in the inner classes info to use
2366 // new constant indices as needed. The inner classes info is a
2367 // quadruple:
2368 // (inner_class_info, outer_class_info, inner_name, inner_access_flags)
2369 InnerClassesIterator iter(scratch_class);
2370 for (; !iter.done(); iter.next()) {
2371 int cur_index = iter.inner_class_info_index();
2372 if (cur_index == 0) {
2373 continue; // JVM spec. allows null inner class refs so skip it
2374 }
2375 int new_index = find_new_index(cur_index);
2376 if (new_index != 0) {
2377 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2378 ("inner_class_info change: %d to %d", cur_index, new_index));
2379 iter.set_inner_class_info_index(new_index);
2380 }
2381 cur_index = iter.outer_class_info_index();
2382 new_index = find_new_index(cur_index);
2383 if (new_index != 0) {
2384 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2385 ("outer_class_info change: %d to %d", cur_index, new_index));
2386 iter.set_outer_class_info_index(new_index);
2387 }
2388 cur_index = iter.inner_name_index();
2389 new_index = find_new_index(cur_index);
2390 if (new_index != 0) {
2391 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2392 ("inner_name change: %d to %d", cur_index, new_index));
2393 iter.set_inner_name_index(new_index);
2394 }
2395 } // end for each inner class
2396
2397 // Attach each method in klass to the new constant pool and update
2398 // to use new constant pool indices as needed:
2399 Array<Method*>* methods = scratch_class->methods();
2400 for (i = methods->length() - 1; i >= 0; i--) {
2401 methodHandle method(THREAD, methods->at(i));
2402 method->set_constants(scratch_cp());
2403
2404 int new_index = find_new_index(method->name_index());
2405 if (new_index != 0) {
2406 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2407 ("method-name_index change: %d to %d", method->name_index(),
2408 new_index));
2409 method->set_name_index(new_index);
2410 }
2411 new_index = find_new_index(method->signature_index());
2412 if (new_index != 0) {
2413 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2414 ("method-signature_index change: %d to %d",
2415 method->signature_index(), new_index));
2416 method->set_signature_index(new_index);
2417 }
2418 new_index = find_new_index(method->generic_signature_index());
2419 if (new_index != 0) {
2420 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2421 ("method-generic_signature_index change: %d to %d",
2422 method->generic_signature_index(), new_index));
2423 method->set_generic_signature_index(new_index);
2424 }
2425
2426 // Update constant pool indices in the method's checked exception
2427 // table to use new constant indices as needed.
2428 int cext_length = method->checked_exceptions_length();
2429 if (cext_length > 0) {
2430 CheckedExceptionElement * cext_table =
2431 method->checked_exceptions_start();
2432 for (int j = 0; j < cext_length; j++) {
2433 int cur_index = cext_table[j].class_cp_index;
2434 int new_index = find_new_index(cur_index);
2435 if (new_index != 0) {
2436 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2437 ("cext-class_cp_index change: %d to %d", cur_index, new_index));
2438 cext_table[j].class_cp_index = (u2)new_index;
2439 }
2440 } // end for each checked exception table entry
2441 } // end if there are checked exception table entries
2442
2443 // Update each catch type index in the method's exception table
2444 // to use new constant pool indices as needed. The exception table
2445 // holds quadruple entries of the form:
2446 // (beg_bci, end_bci, handler_bci, klass_index)
2447
2448 ExceptionTable ex_table(method());
2449 int ext_length = ex_table.length();
2450
2451 for (int j = 0; j < ext_length; j ++) {
2452 int cur_index = ex_table.catch_type_index(j);
2453 int new_index = find_new_index(cur_index);
2454 if (new_index != 0) {
2455 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2456 ("ext-klass_index change: %d to %d", cur_index, new_index));
2457 ex_table.set_catch_type_index(j, new_index);
2458 }
2459 } // end for each exception table entry
2460
2461 // Update constant pool indices in the method's local variable
2462 // table to use new constant indices as needed. The local variable
2463 // table hold sextuple entries of the form:
2464 // (start_pc, length, name_index, descriptor_index, signature_index, slot)
2465 int lvt_length = method->localvariable_table_length();
2466 if (lvt_length > 0) {
2467 LocalVariableTableElement * lv_table =
2468 method->localvariable_table_start();
2469 for (int j = 0; j < lvt_length; j++) {
2470 int cur_index = lv_table[j].name_cp_index;
2471 int new_index = find_new_index(cur_index);
2472 if (new_index != 0) {
2473 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2474 ("lvt-name_cp_index change: %d to %d", cur_index, new_index));
2475 lv_table[j].name_cp_index = (u2)new_index;
2476 }
2477 cur_index = lv_table[j].descriptor_cp_index;
2478 new_index = find_new_index(cur_index);
2479 if (new_index != 0) {
2480 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2481 ("lvt-descriptor_cp_index change: %d to %d", cur_index,
2482 new_index));
2483 lv_table[j].descriptor_cp_index = (u2)new_index;
2484 }
2485 cur_index = lv_table[j].signature_cp_index;
2486 new_index = find_new_index(cur_index);
2487 if (new_index != 0) {
2488 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2489 ("lvt-signature_cp_index change: %d to %d", cur_index, new_index));
2490 lv_table[j].signature_cp_index = (u2)new_index;
2491 }
2492 } // end for each local variable table entry
2493 } // end if there are local variable table entries
2494
2495 rewrite_cp_refs_in_stack_map_table(method, THREAD);
2496 } // end for each method
2497 } // end set_new_constant_pool()
2498
2499
2500 void VM_RedefineClasses::adjust_array_vtable(Klass* k_oop) {
2501 ArrayKlass* ak = ArrayKlass::cast(k_oop);
2502 bool trace_name_printed = false;
2503 ak->vtable()->adjust_method_entries(_matching_old_methods,
2504 _matching_new_methods,
2505 _matching_methods_length,
2506 &trace_name_printed);
2507 }
2508
2509 // Unevolving classes may point to methods of the_class directly
2510 // from their constant pool caches, itables, and/or vtables. We
2511 // use the SystemDictionary::classes_do() facility and this helper
2512 // to fix up these pointers.
2513 //
2514 // Note: We currently don't support updating the vtable in
2515 // arrayKlassOops. See Open Issues in jvmtiRedefineClasses.hpp.
2516 void VM_RedefineClasses::adjust_cpool_cache_and_vtable(Klass* k_oop,
2517 ClassLoaderData* initiating_loader,
2518 TRAPS) {
2519 Klass *k = k_oop;
2520 if (k->oop_is_instance()) {
2521 HandleMark hm(THREAD);
2522 InstanceKlass *ik = (InstanceKlass *) k;
2523
2524 // HotSpot specific optimization! HotSpot does not currently
2525 // support delegation from the bootstrap class loader to a
2526 // user-defined class loader. This means that if the bootstrap
2527 // class loader is the initiating class loader, then it will also
2528 // be the defining class loader. This also means that classes
2529 // loaded by the bootstrap class loader cannot refer to classes
2530 // loaded by a user-defined class loader. Note: a user-defined
2531 // class loader can delegate to the bootstrap class loader.
2532 //
2533 // If the current class being redefined has a user-defined class
2534 // loader as its defining class loader, then we can skip all
2535 // classes loaded by the bootstrap class loader.
2536 bool is_user_defined =
2537 InstanceKlass::cast(_the_class_oop)->class_loader() != NULL;
2538 if (is_user_defined && ik->class_loader() == NULL) {
2539 return;
2540 }
2541
2542 // If the class being redefined is java.lang.Object, we need to fix all
2543 // array class vtables also
2544 if (_the_class_oop == SystemDictionary::Object_klass()) {
2545 ik->array_klasses_do(adjust_array_vtable);
2546 }
2547
2548 // This is a very busy routine. We don't want too much tracing
2549 // printed out.
2550 bool trace_name_printed = false;
2551
2552 // Very noisy: only enable this call if you are trying to determine
2553 // that a specific class gets found by this routine.
2554 // RC_TRACE macro has an embedded ResourceMark
2555 // RC_TRACE_WITH_THREAD(0x00100000, THREAD,
2556 // ("adjust check: name=%s", ik->external_name()));
2557 // trace_name_printed = true;
2558
2559 // Fix the vtable embedded in the_class and subclasses of the_class,
2560 // if one exists. We discard scratch_class and we don't keep an
2561 // InstanceKlass around to hold obsolete methods so we don't have
2562 // any other InstanceKlass embedded vtables to update. The vtable
2563 // holds the Method*s for virtual (but not final) methods.
2564 if (ik->vtable_length() > 0 && ik->is_subtype_of(_the_class_oop)) {
2565 // ik->vtable() creates a wrapper object; rm cleans it up
2566 ResourceMark rm(THREAD);
2567 ik->vtable()->adjust_method_entries(_matching_old_methods,
2568 _matching_new_methods,
2569 _matching_methods_length,
2570 &trace_name_printed);
2571 }
2572
2573 // If the current class has an itable and we are either redefining an
2574 // interface or if the current class is a subclass of the_class, then
2575 // we potentially have to fix the itable. If we are redefining an
2576 // interface, then we have to call adjust_method_entries() for
2577 // every InstanceKlass that has an itable since there isn't a
2578 // subclass relationship between an interface and an InstanceKlass.
2579 if (ik->itable_length() > 0 && (_the_class_oop->is_interface()
2580 || ik->is_subclass_of(_the_class_oop))) {
2581 // ik->itable() creates a wrapper object; rm cleans it up
2582 ResourceMark rm(THREAD);
2583 ik->itable()->adjust_method_entries(_matching_old_methods,
2584 _matching_new_methods,
2585 _matching_methods_length,
2586 &trace_name_printed);
2587 }
2588
2589 // The constant pools in other classes (other_cp) can refer to
2590 // methods in the_class. We have to update method information in
2591 // other_cp's cache. If other_cp has a previous version, then we
2592 // have to repeat the process for each previous version. The
2593 // constant pool cache holds the Method*s for non-virtual
2594 // methods and for virtual, final methods.
2595 //
2596 // Special case: if the current class is the_class, then new_cp
2597 // has already been attached to the_class and old_cp has already
2598 // been added as a previous version. The new_cp doesn't have any
2599 // cached references to old methods so it doesn't need to be
2600 // updated. We can simply start with the previous version(s) in
2601 // that case.
2602 constantPoolHandle other_cp;
2603 ConstantPoolCache* cp_cache;
2604
2605 if (k_oop != _the_class_oop) {
2606 // this klass' constant pool cache may need adjustment
2607 other_cp = constantPoolHandle(ik->constants());
2608 cp_cache = other_cp->cache();
2609 if (cp_cache != NULL) {
2610 cp_cache->adjust_method_entries(_matching_old_methods,
2611 _matching_new_methods,
2612 _matching_methods_length,
2613 &trace_name_printed);
2614 }
2615 }
2616 {
2617 ResourceMark rm(THREAD);
2618 // PreviousVersionInfo objects returned via PreviousVersionWalker
2619 // contain a GrowableArray of handles. We have to clean up the
2620 // GrowableArray _after_ the PreviousVersionWalker destructor
2621 // has destroyed the handles.
2622 {
2623 // the previous versions' constant pool caches may need adjustment
2624 PreviousVersionWalker pvw(ik);
2625 for (PreviousVersionInfo * pv_info = pvw.next_previous_version();
2626 pv_info != NULL; pv_info = pvw.next_previous_version()) {
2627 other_cp = pv_info->prev_constant_pool_handle();
2628 cp_cache = other_cp->cache();
2629 if (cp_cache != NULL) {
2630 cp_cache->adjust_method_entries(_matching_old_methods,
2631 _matching_new_methods,
2632 _matching_methods_length,
2633 &trace_name_printed);
2634 }
2635 }
2636 } // pvw is cleaned up
2637 } // rm is cleaned up
2638 }
2639 }
2640
2641 void VM_RedefineClasses::update_jmethod_ids() {
2642 for (int j = 0; j < _matching_methods_length; ++j) {
2643 Method* old_method = _matching_old_methods[j];
2644 jmethodID jmid = old_method->find_jmethod_id_or_null();
2645 if (jmid != NULL) {
2646 // There is a jmethodID, change it to point to the new method
2647 methodHandle new_method_h(_matching_new_methods[j]);
2648 Method::change_method_associated_with_jmethod_id(jmid, new_method_h());
2649 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j],
2650 "should be replaced");
2651 }
2652 }
2653 }
2654
2655 void VM_RedefineClasses::check_methods_and_mark_as_obsolete(
2656 BitMap *emcp_methods, int * emcp_method_count_p) {
2657 *emcp_method_count_p = 0;
2658 int obsolete_count = 0;
2659 int old_index = 0;
2660 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
2661 Method* old_method = _matching_old_methods[j];
2662 Method* new_method = _matching_new_methods[j];
2663 Method* old_array_method;
2664
2665 // Maintain an old_index into the _old_methods array by skipping
2666 // deleted methods
2667 while ((old_array_method = _old_methods->at(old_index)) != old_method) {
2668 ++old_index;
2669 }
2670
2671 if (MethodComparator::methods_EMCP(old_method, new_method)) {
2672 // The EMCP definition from JSR-163 requires the bytecodes to be
2673 // the same with the exception of constant pool indices which may
2674 // differ. However, the constants referred to by those indices
2675 // must be the same.
2676 //
2677 // We use methods_EMCP() for comparison since constant pool
2678 // merging can remove duplicate constant pool entries that were
2679 // present in the old method and removed from the rewritten new
2680 // method. A faster binary comparison function would consider the
2681 // old and new methods to be different when they are actually
2682 // EMCP.
2683 //
2684 // The old and new methods are EMCP and you would think that we
2685 // could get rid of one of them here and now and save some space.
2686 // However, the concept of EMCP only considers the bytecodes and
2687 // the constant pool entries in the comparison. Other things,
2688 // e.g., the line number table (LNT) or the local variable table
2689 // (LVT) don't count in the comparison. So the new (and EMCP)
2690 // method can have a new LNT that we need so we can't just
2691 // overwrite the new method with the old method.
2692 //
2693 // When this routine is called, we have already attached the new
2694 // methods to the_class so the old methods are effectively
2695 // overwritten. However, if an old method is still executing,
2696 // then the old method cannot be collected until sometime after
2697 // the old method call has returned. So the overwriting of old
2698 // methods by new methods will save us space except for those
2699 // (hopefully few) old methods that are still executing.
2700 //
2701 // A method refers to a ConstMethod* and this presents another
2702 // possible avenue to space savings. The ConstMethod* in the
2703 // new method contains possibly new attributes (LNT, LVT, etc).
2704 // At first glance, it seems possible to save space by replacing
2705 // the ConstMethod* in the old method with the ConstMethod*
2706 // from the new method. The old and new methods would share the
2707 // same ConstMethod* and we would save the space occupied by
2708 // the old ConstMethod*. However, the ConstMethod* contains
2709 // a back reference to the containing method. Sharing the
2710 // ConstMethod* between two methods could lead to confusion in
2711 // the code that uses the back reference. This would lead to
2712 // brittle code that could be broken in non-obvious ways now or
2713 // in the future.
2714 //
2715 // Another possibility is to copy the ConstMethod* from the new
2716 // method to the old method and then overwrite the new method with
2717 // the old method. Since the ConstMethod* contains the bytecodes
2718 // for the method embedded in the oop, this option would change
2719 // the bytecodes out from under any threads executing the old
2720 // method and make the thread's bcp invalid. Since EMCP requires
2721 // that the bytecodes be the same modulo constant pool indices, it
2722 // is straight forward to compute the correct new bcp in the new
2723 // ConstMethod* from the old bcp in the old ConstMethod*. The
2724 // time consuming part would be searching all the frames in all
2725 // of the threads to find all of the calls to the old method.
2726 //
2727 // It looks like we will have to live with the limited savings
2728 // that we get from effectively overwriting the old methods
2729 // when the new methods are attached to the_class.
2730
2731 // track which methods are EMCP for add_previous_version() call
2732 emcp_methods->set_bit(old_index);
2733 (*emcp_method_count_p)++;
2734
2735 // An EMCP method is _not_ obsolete. An obsolete method has a
2736 // different jmethodID than the current method. An EMCP method
2737 // has the same jmethodID as the current method. Having the
2738 // same jmethodID for all EMCP versions of a method allows for
2739 // a consistent view of the EMCP methods regardless of which
2740 // EMCP method you happen to have in hand. For example, a
2741 // breakpoint set in one EMCP method will work for all EMCP
2742 // versions of the method including the current one.
2743 } else {
2744 // mark obsolete methods as such
2745 old_method->set_is_obsolete();
2746 obsolete_count++;
2747
2748 // obsolete methods need a unique idnum
2749 u2 num = InstanceKlass::cast(_the_class_oop)->next_method_idnum();
2750 if (num != ConstMethod::UNSET_IDNUM) {
2751 // u2 old_num = old_method->method_idnum();
2752 old_method->set_method_idnum(num);
2753 // TO DO: attach obsolete annotations to obsolete method's new idnum
2754 }
2755 // With tracing we try not to "yack" too much. The position of
2756 // this trace assumes there are fewer obsolete methods than
2757 // EMCP methods.
2758 RC_TRACE(0x00000100, ("mark %s(%s) as obsolete",
2759 old_method->name()->as_C_string(),
2760 old_method->signature()->as_C_string()));
2761 }
2762 old_method->set_is_old();
2763 }
2764 for (int i = 0; i < _deleted_methods_length; ++i) {
2765 Method* old_method = _deleted_methods[i];
2766
2767 assert(old_method->vtable_index() < 0,
2768 "cannot delete methods with vtable entries");;
2769
2770 // Mark all deleted methods as old and obsolete
2771 old_method->set_is_old();
2772 old_method->set_is_obsolete();
2773 ++obsolete_count;
2774 // With tracing we try not to "yack" too much. The position of
2775 // this trace assumes there are fewer obsolete methods than
2776 // EMCP methods.
2777 RC_TRACE(0x00000100, ("mark deleted %s(%s) as obsolete",
2778 old_method->name()->as_C_string(),
2779 old_method->signature()->as_C_string()));
2780 }
2781 assert((*emcp_method_count_p + obsolete_count) == _old_methods->length(),
2782 "sanity check");
2783 RC_TRACE(0x00000100, ("EMCP_cnt=%d, obsolete_cnt=%d", *emcp_method_count_p,
2784 obsolete_count));
2785 }
2786
2787 // This internal class transfers the native function registration from old methods
2788 // to new methods. It is designed to handle both the simple case of unchanged
2789 // native methods and the complex cases of native method prefixes being added and/or
2790 // removed.
2791 // It expects only to be used during the VM_RedefineClasses op (a safepoint).
2792 //
2793 // This class is used after the new methods have been installed in "the_class".
2794 //
2795 // So, for example, the following must be handled. Where 'm' is a method and
2796 // a number followed by an underscore is a prefix.
2797 //
2798 // Old Name New Name
2799 // Simple transfer to new method m -> m
2800 // Add prefix m -> 1_m
2801 // Remove prefix 1_m -> m
2802 // Simultaneous add of prefixes m -> 3_2_1_m
2803 // Simultaneous removal of prefixes 3_2_1_m -> m
2804 // Simultaneous add and remove 1_m -> 2_m
2805 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m
2806 //
2807 class TransferNativeFunctionRegistration {
2808 private:
2809 instanceKlassHandle the_class;
2810 int prefix_count;
2811 char** prefixes;
2812
2813 // Recursively search the binary tree of possibly prefixed method names.
2814 // Iteration could be used if all agents were well behaved. Full tree walk is
2815 // more resilent to agents not cleaning up intermediate methods.
2816 // Branch at each depth in the binary tree is:
2817 // (1) without the prefix.
2818 // (2) with the prefix.
2819 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
2820 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len,
2821 Symbol* signature) {
2822 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len);
2823 if (name_symbol != NULL) {
2824 Method* method = the_class()->lookup_method(name_symbol, signature);
2825 if (method != NULL) {
2826 // Even if prefixed, intermediate methods must exist.
2827 if (method->is_native()) {
2828 // Wahoo, we found a (possibly prefixed) version of the method, return it.
2829 return method;
2830 }
2831 if (depth < prefix_count) {
2832 // Try applying further prefixes (other than this one).
2833 method = search_prefix_name_space(depth+1, name_str, name_len, signature);
2834 if (method != NULL) {
2835 return method; // found
2836 }
2837
2838 // Try adding this prefix to the method name and see if it matches
2839 // another method name.
2840 char* prefix = prefixes[depth];
2841 size_t prefix_len = strlen(prefix);
2842 size_t trial_len = name_len + prefix_len;
2843 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
2844 strcpy(trial_name_str, prefix);
2845 strcat(trial_name_str, name_str);
2846 method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
2847 signature);
2848 if (method != NULL) {
2849 // If found along this branch, it was prefixed, mark as such
2850 method->set_is_prefixed_native();
2851 return method; // found
2852 }
2853 }
2854 }
2855 }
2856 return NULL; // This whole branch bore nothing
2857 }
2858
2859 // Return the method name with old prefixes stripped away.
2860 char* method_name_without_prefixes(Method* method) {
2861 Symbol* name = method->name();
2862 char* name_str = name->as_utf8();
2863
2864 // Old prefixing may be defunct, strip prefixes, if any.
2865 for (int i = prefix_count-1; i >= 0; i--) {
2866 char* prefix = prefixes[i];
2867 size_t prefix_len = strlen(prefix);
2868 if (strncmp(prefix, name_str, prefix_len) == 0) {
2869 name_str += prefix_len;
2870 }
2871 }
2872 return name_str;
2873 }
2874
2875 // Strip any prefixes off the old native method, then try to find a
2876 // (possibly prefixed) new native that matches it.
2877 Method* strip_and_search_for_new_native(Method* method) {
2878 ResourceMark rm;
2879 char* name_str = method_name_without_prefixes(method);
2880 return search_prefix_name_space(0, name_str, strlen(name_str),
2881 method->signature());
2882 }
2883
2884 public:
2885
2886 // Construct a native method transfer processor for this class.
2887 TransferNativeFunctionRegistration(instanceKlassHandle _the_class) {
2888 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
2889
2890 the_class = _the_class;
2891 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
2892 }
2893
2894 // Attempt to transfer any of the old or deleted methods that are native
2895 void transfer_registrations(Method** old_methods, int methods_length) {
2896 for (int j = 0; j < methods_length; j++) {
2897 Method* old_method = old_methods[j];
2898
2899 if (old_method->is_native() && old_method->has_native_function()) {
2900 Method* new_method = strip_and_search_for_new_native(old_method);
2901 if (new_method != NULL) {
2902 // Actually set the native function in the new method.
2903 // Redefine does not send events (except CFLH), certainly not this
2904 // behind the scenes re-registration.
2905 new_method->set_native_function(old_method->native_function(),
2906 !Method::native_bind_event_is_interesting);
2907 }
2908 }
2909 }
2910 }
2911 };
2912
2913 // Don't lose the association between a native method and its JNI function.
2914 void VM_RedefineClasses::transfer_old_native_function_registrations(instanceKlassHandle the_class) {
2915 TransferNativeFunctionRegistration transfer(the_class);
2916 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length);
2917 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length);
2918 }
2919
2920 // Deoptimize all compiled code that depends on this class.
2921 //
2922 // If the can_redefine_classes capability is obtained in the onload
2923 // phase then the compiler has recorded all dependencies from startup.
2924 // In that case we need only deoptimize and throw away all compiled code
2925 // that depends on the class.
2926 //
2927 // If can_redefine_classes is obtained sometime after the onload
2928 // phase then the dependency information may be incomplete. In that case
2929 // the first call to RedefineClasses causes all compiled code to be
2930 // thrown away. As can_redefine_classes has been obtained then
2931 // all future compilations will record dependencies so second and
2932 // subsequent calls to RedefineClasses need only throw away code
2933 // that depends on the class.
2934 //
2935 void VM_RedefineClasses::flush_dependent_code(instanceKlassHandle k_h, TRAPS) {
2936 assert_locked_or_safepoint(Compile_lock);
2937
2938 // All dependencies have been recorded from startup or this is a second or
2939 // subsequent use of RedefineClasses
2940 if (JvmtiExport::all_dependencies_are_recorded()) {
2941 Universe::flush_evol_dependents_on(k_h);
2942 } else {
2943 CodeCache::mark_all_nmethods_for_deoptimization();
2944
2945 ResourceMark rm(THREAD);
2946 DeoptimizationMarker dm;
2947
2948 // Deoptimize all activations depending on marked nmethods
2949 Deoptimization::deoptimize_dependents();
2950
2951 // Make the dependent methods not entrant (in VM_Deoptimize they are made zombies)
2952 CodeCache::make_marked_nmethods_not_entrant();
2953
2954 // From now on we know that the dependency information is complete
2955 JvmtiExport::set_all_dependencies_are_recorded(true);
2956 }
2957 }
2958
2959 void VM_RedefineClasses::compute_added_deleted_matching_methods() {
2960 Method* old_method;
2961 Method* new_method;
2962
2963 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
2964 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
2965 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length());
2966 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
2967
2968 _matching_methods_length = 0;
2969 _deleted_methods_length = 0;
2970 _added_methods_length = 0;
2971
2972 int nj = 0;
2973 int oj = 0;
2974 while (true) {
2975 if (oj >= _old_methods->length()) {
2976 if (nj >= _new_methods->length()) {
2977 break; // we've looked at everything, done
2978 }
2979 // New method at the end
2980 new_method = _new_methods->at(nj);
2981 _added_methods[_added_methods_length++] = new_method;
2982 ++nj;
2983 } else if (nj >= _new_methods->length()) {
2984 // Old method, at the end, is deleted
2985 old_method = _old_methods->at(oj);
2986 _deleted_methods[_deleted_methods_length++] = old_method;
2987 ++oj;
2988 } else {
2989 old_method = _old_methods->at(oj);
2990 new_method = _new_methods->at(nj);
2991 if (old_method->name() == new_method->name()) {
2992 if (old_method->signature() == new_method->signature()) {
2993 _matching_old_methods[_matching_methods_length ] = old_method;
2994 _matching_new_methods[_matching_methods_length++] = new_method;
2995 ++nj;
2996 ++oj;
2997 } else {
2998 // added overloaded have already been moved to the end,
2999 // so this is a deleted overloaded method
3000 _deleted_methods[_deleted_methods_length++] = old_method;
3001 ++oj;
3002 }
3003 } else { // names don't match
3004 if (old_method->name()->fast_compare(new_method->name()) > 0) {
3005 // new method
3006 _added_methods[_added_methods_length++] = new_method;
3007 ++nj;
3008 } else {
3009 // deleted method
3010 _deleted_methods[_deleted_methods_length++] = old_method;
3011 ++oj;
3012 }
3013 }
3014 }
3015 }
3016 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
3017 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
3018 }
3019
3020
3021 void VM_RedefineClasses::swap_annotations(instanceKlassHandle the_class,
3022 instanceKlassHandle scratch_class) {
3023 // Since there is currently no rewriting of type annotations indexes
3024 // into the CP, we null out type annotations on scratch_class before
3025 // we swap annotations with the_class rather than facing the
3026 // possibility of shipping annotations with broken indexes to
3027 // Java-land.
3028 ClassLoaderData* loader_data = scratch_class->class_loader_data();
3029 AnnotationArray* new_class_type_annotations = scratch_class->class_type_annotations();
3030 if (new_class_type_annotations != NULL) {
3031 MetadataFactory::free_array<u1>(loader_data, new_class_type_annotations);
3032 scratch_class->annotations()->set_class_type_annotations(NULL);
3033 }
3034 Array<AnnotationArray*>* new_field_type_annotations = scratch_class->fields_type_annotations();
3035 if (new_field_type_annotations != NULL) {
3036 Annotations::free_contents(loader_data, new_field_type_annotations);
3037 scratch_class->annotations()->set_fields_type_annotations(NULL);
3038 }
3039
3040 // Swap annotation fields values
3041 Annotations* old_annotations = the_class->annotations();
3042 the_class->set_annotations(scratch_class->annotations());
3043 scratch_class->set_annotations(old_annotations);
3044 }
3045
3046
3047 // Install the redefinition of a class:
3048 // - house keeping (flushing breakpoints and caches, deoptimizing
3049 // dependent compiled code)
3050 // - replacing parts in the_class with parts from scratch_class
3051 // - adding a weak reference to track the obsolete but interesting
3052 // parts of the_class
3053 // - adjusting constant pool caches and vtables in other classes
3054 // that refer to methods in the_class. These adjustments use the
3055 // SystemDictionary::classes_do() facility which only allows
3056 // a helper method to be specified. The interesting parameters
3057 // that we would like to pass to the helper method are saved in
3058 // static global fields in the VM operation.
3059 void VM_RedefineClasses::redefine_single_class(jclass the_jclass,
3060 Klass* scratch_class_oop, TRAPS) {
3061
3062 HandleMark hm(THREAD); // make sure handles from this call are freed
3063 RC_TIMER_START(_timer_rsc_phase1);
3064
3065 instanceKlassHandle scratch_class(scratch_class_oop);
3066
3067 oop the_class_mirror = JNIHandles::resolve_non_null(the_jclass);
3068 Klass* the_class_oop = java_lang_Class::as_Klass(the_class_mirror);
3069 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
3070
3071 // Remove all breakpoints in methods of this class
3072 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
3073 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class_oop);
3074
3075 if (the_class_oop == Universe::reflect_invoke_cache()->klass()) {
3076 // We are redefining java.lang.reflect.Method. Method.invoke() is
3077 // cached and users of the cache care about each active version of
3078 // the method so we have to track this previous version.
3079 // Do this before methods get switched
3080 Universe::reflect_invoke_cache()->add_previous_version(
3081 the_class->method_with_idnum(Universe::reflect_invoke_cache()->method_idnum()));
3082 }
3083
3084 // Deoptimize all compiled code that depends on this class
3085 flush_dependent_code(the_class, THREAD);
3086
3087 _old_methods = the_class->methods();
3088 _new_methods = scratch_class->methods();
3089 _the_class_oop = the_class_oop;
3090 compute_added_deleted_matching_methods();
3091 update_jmethod_ids();
3092
3093 // Attach new constant pool to the original klass. The original
3094 // klass still refers to the old constant pool (for now).
3095 scratch_class->constants()->set_pool_holder(the_class());
3096
3097 #if 0
3098 // In theory, with constant pool merging in place we should be able
3099 // to save space by using the new, merged constant pool in place of
3100 // the old constant pool(s). By "pool(s)" I mean the constant pool in
3101 // the klass version we are replacing now and any constant pool(s) in
3102 // previous versions of klass. Nice theory, doesn't work in practice.
3103 // When this code is enabled, even simple programs throw NullPointer
3104 // exceptions. I'm guessing that this is caused by some constant pool
3105 // cache difference between the new, merged constant pool and the
3106 // constant pool that was just being used by the klass. I'm keeping
3107 // this code around to archive the idea, but the code has to remain
3108 // disabled for now.
3109
3110 // Attach each old method to the new constant pool. This can be
3111 // done here since we are past the bytecode verification and
3112 // constant pool optimization phases.
3113 for (int i = _old_methods->length() - 1; i >= 0; i--) {
3114 Method* method = _old_methods->at(i);
3115 method->set_constants(scratch_class->constants());
3116 }
3117
3118 {
3119 // walk all previous versions of the klass
3120 InstanceKlass *ik = (InstanceKlass *)the_class();
3121 PreviousVersionWalker pvw(ik);
3122 instanceKlassHandle ikh;
3123 do {
3124 ikh = pvw.next_previous_version();
3125 if (!ikh.is_null()) {
3126 ik = ikh();
3127
3128 // attach previous version of klass to the new constant pool
3129 ik->set_constants(scratch_class->constants());
3130
3131 // Attach each method in the previous version of klass to the
3132 // new constant pool
3133 Array<Method*>* prev_methods = ik->methods();
3134 for (int i = prev_methods->length() - 1; i >= 0; i--) {
3135 Method* method = prev_methods->at(i);
3136 method->set_constants(scratch_class->constants());
3137 }
3138 }
3139 } while (!ikh.is_null());
3140 }
3141 #endif
3142
3143 // Replace methods and constantpool
3144 the_class->set_methods(_new_methods);
3145 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods,
3146 // and to be able to undo operation easily.
3147
3148 ConstantPool* old_constants = the_class->constants();
3149 the_class->set_constants(scratch_class->constants());
3150 scratch_class->set_constants(old_constants); // See the previous comment.
3151 #if 0
3152 // We are swapping the guts of "the new class" with the guts of "the
3153 // class". Since the old constant pool has just been attached to "the
3154 // new class", it seems logical to set the pool holder in the old
3155 // constant pool also. However, doing this will change the observable
3156 // class hierarchy for any old methods that are still executing. A
3157 // method can query the identity of its "holder" and this query uses
3158 // the method's constant pool link to find the holder. The change in
3159 // holding class from "the class" to "the new class" can confuse
3160 // things.
3161 //
3162 // Setting the old constant pool's holder will also cause
3163 // verification done during vtable initialization below to fail.
3164 // During vtable initialization, the vtable's class is verified to be
3165 // a subtype of the method's holder. The vtable's class is "the
3166 // class" and the method's holder is gotten from the constant pool
3167 // link in the method itself. For "the class"'s directly implemented
3168 // methods, the method holder is "the class" itself (as gotten from
3169 // the new constant pool). The check works fine in this case. The
3170 // check also works fine for methods inherited from super classes.
3171 //
3172 // Miranda methods are a little more complicated. A miranda method is
3173 // provided by an interface when the class implementing the interface
3174 // does not provide its own method. These interfaces are implemented
3175 // internally as an InstanceKlass. These special instanceKlasses
3176 // share the constant pool of the class that "implements" the
3177 // interface. By sharing the constant pool, the method holder of a
3178 // miranda method is the class that "implements" the interface. In a
3179 // non-redefine situation, the subtype check works fine. However, if
3180 // the old constant pool's pool holder is modified, then the check
3181 // fails because there is no class hierarchy relationship between the
3182 // vtable's class and "the new class".
3183
3184 old_constants->set_pool_holder(scratch_class());
3185 #endif
3186
3187 // track which methods are EMCP for add_previous_version() call below
3188 BitMap emcp_methods(_old_methods->length());
3189 int emcp_method_count = 0;
3190 emcp_methods.clear(); // clears 0..(length() - 1)
3191 check_methods_and_mark_as_obsolete(&emcp_methods, &emcp_method_count);
3192 transfer_old_native_function_registrations(the_class);
3193
3194 // The class file bytes from before any retransformable agents mucked
3195 // with them was cached on the scratch class, move to the_class.
3196 // Note: we still want to do this if nothing needed caching since it
3197 // should get cleared in the_class too.
3198 if (the_class->get_cached_class_file_bytes() == 0) {
3199 // the_class doesn't have a cache yet so copy it
3200 the_class->set_cached_class_file(
3201 scratch_class->get_cached_class_file_bytes(),
3202 scratch_class->get_cached_class_file_len());
3203 }
3204 #ifndef PRODUCT
3205 else {
3206 assert(the_class->get_cached_class_file_bytes() ==
3207 scratch_class->get_cached_class_file_bytes(), "cache ptrs must match");
3208 assert(the_class->get_cached_class_file_len() ==
3209 scratch_class->get_cached_class_file_len(), "cache lens must match");
3210 }
3211 #endif
3212
3213 // Replace inner_classes
3214 Array<u2>* old_inner_classes = the_class->inner_classes();
3215 the_class->set_inner_classes(scratch_class->inner_classes());
3216 scratch_class->set_inner_classes(old_inner_classes);
3217
3218 // Initialize the vtable and interface table after
3219 // methods have been rewritten
3220 {
3221 ResourceMark rm(THREAD);
3222 // no exception should happen here since we explicitly
3223 // do not check loader constraints.
3224 // compare_and_normalize_class_versions has already checked:
3225 // - classloaders unchanged, signatures unchanged
3226 // - all instanceKlasses for redefined classes reused & contents updated
3227 the_class->vtable()->initialize_vtable(false, THREAD);
3228 the_class->itable()->initialize_itable(false, THREAD);
3229 assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())), "redefine exception");
3230 }
3231
3232 // Leave arrays of jmethodIDs and itable index cache unchanged
3233
3234 // Copy the "source file name" attribute from new class version
3235 the_class->set_source_file_name(scratch_class->source_file_name());
3236
3237 // Copy the "source debug extension" attribute from new class version
3238 the_class->set_source_debug_extension(
3239 scratch_class->source_debug_extension(),
3240 scratch_class->source_debug_extension() == NULL ? 0 :
3241 (int)strlen(scratch_class->source_debug_extension()));
3242
3243 // Use of javac -g could be different in the old and the new
3244 if (scratch_class->access_flags().has_localvariable_table() !=
3245 the_class->access_flags().has_localvariable_table()) {
3246
3247 AccessFlags flags = the_class->access_flags();
3248 if (scratch_class->access_flags().has_localvariable_table()) {
3249 flags.set_has_localvariable_table();
3250 } else {
3251 flags.clear_has_localvariable_table();
3252 }
3253 the_class->set_access_flags(flags);
3254 }
3255
3256 swap_annotations(the_class, scratch_class);
3257
3258 // Replace minor version number of class file
3259 u2 old_minor_version = the_class->minor_version();
3260 the_class->set_minor_version(scratch_class->minor_version());
3261 scratch_class->set_minor_version(old_minor_version);
3262
3263 // Replace major version number of class file
3264 u2 old_major_version = the_class->major_version();
3265 the_class->set_major_version(scratch_class->major_version());
3266 scratch_class->set_major_version(old_major_version);
3267
3268 // Replace CP indexes for class and name+type of enclosing method
3269 u2 old_class_idx = the_class->enclosing_method_class_index();
3270 u2 old_method_idx = the_class->enclosing_method_method_index();
3271 the_class->set_enclosing_method_indices(
3272 scratch_class->enclosing_method_class_index(),
3273 scratch_class->enclosing_method_method_index());
3274 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx);
3275
3276 // keep track of previous versions of this class
3277 the_class->add_previous_version(scratch_class, &emcp_methods,
3278 emcp_method_count);
3279
3280 RC_TIMER_STOP(_timer_rsc_phase1);
3281 RC_TIMER_START(_timer_rsc_phase2);
3282
3283 // Adjust constantpool caches and vtables for all classes
3284 // that reference methods of the evolved class.
3285 SystemDictionary::classes_do(adjust_cpool_cache_and_vtable, THREAD);
3286
3287 // Fix Resolution Error table also to remove old constant pools
3288 SystemDictionary::delete_resolution_error(old_constants);
3289
3290 if (the_class->oop_map_cache() != NULL) {
3291 // Flush references to any obsolete methods from the oop map cache
3292 // so that obsolete methods are not pinned.
3293 the_class->oop_map_cache()->flush_obsolete_entries();
3294 }
3295
3296 // increment the classRedefinedCount field in the_class and in any
3297 // direct and indirect subclasses of the_class
3298 increment_class_counter((InstanceKlass *)the_class(), THREAD);
3299
3300 // RC_TRACE macro has an embedded ResourceMark
3301 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
3302 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)",
3303 the_class->external_name(),
3304 java_lang_Class::classRedefinedCount(the_class_mirror),
3305 os::available_memory() >> 10));
3306
3307 RC_TIMER_STOP(_timer_rsc_phase2);
3308 } // end redefine_single_class()
3309
3310
3311 // Increment the classRedefinedCount field in the specific InstanceKlass
3312 // and in all direct and indirect subclasses.
3313 void VM_RedefineClasses::increment_class_counter(InstanceKlass *ik, TRAPS) {
3314 oop class_mirror = ik->java_mirror();
3315 Klass* class_oop = java_lang_Class::as_Klass(class_mirror);
3316 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
3317 java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
3318
3319 if (class_oop != _the_class_oop) {
3320 // _the_class_oop count is printed at end of redefine_single_class()
3321 RC_TRACE_WITH_THREAD(0x00000008, THREAD,
3322 ("updated count in subclass=%s to %d", ik->external_name(), new_count));
3323 }
3324
3325 for (Klass *subk = ik->subklass(); subk != NULL;
3326 subk = subk->next_sibling()) {
3327 if (subk->oop_is_instance()) {
3328 // Only update instanceKlasses
3329 InstanceKlass *subik = (InstanceKlass*)subk;
3330 // recursively do subclasses of the current subclass
3331 increment_class_counter(subik, THREAD);
3332 }
3333 }
3334 }
3335
3336 void VM_RedefineClasses::check_class(Klass* k_oop,
3337 ClassLoaderData* initiating_loader,
3338 TRAPS) {
3339 Klass *k = k_oop;
3340 if (k->oop_is_instance()) {
3341 HandleMark hm(THREAD);
3342 InstanceKlass *ik = (InstanceKlass *) k;
3343 bool no_old_methods = true; // be optimistic
3344 ResourceMark rm(THREAD);
3345
3346 // a vtable should never contain old or obsolete methods
3347 if (ik->vtable_length() > 0 &&
3348 !ik->vtable()->check_no_old_or_obsolete_entries()) {
3349 if (RC_TRACE_ENABLED(0x00004000)) {
3350 RC_TRACE_WITH_THREAD(0x00004000, THREAD,
3351 ("klassVtable::check_no_old_or_obsolete_entries failure"
3352 " -- OLD or OBSOLETE method found -- class: %s",
3353 ik->signature_name()));
3354 ik->vtable()->dump_vtable();
3355 }
3356 no_old_methods = false;
3357 }
3358
3359 // an itable should never contain old or obsolete methods
3360 if (ik->itable_length() > 0 &&
3361 !ik->itable()->check_no_old_or_obsolete_entries()) {
3362 if (RC_TRACE_ENABLED(0x00004000)) {
3363 RC_TRACE_WITH_THREAD(0x00004000, THREAD,
3364 ("klassItable::check_no_old_or_obsolete_entries failure"
3365 " -- OLD or OBSOLETE method found -- class: %s",
3366 ik->signature_name()));
3367 ik->itable()->dump_itable();
3368 }
3369 no_old_methods = false;
3370 }
3371
3372 // the constant pool cache should never contain old or obsolete methods
3373 if (ik->constants() != NULL &&
3374 ik->constants()->cache() != NULL &&
3375 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) {
3376 if (RC_TRACE_ENABLED(0x00004000)) {
3377 RC_TRACE_WITH_THREAD(0x00004000, THREAD,
3378 ("cp-cache::check_no_old_or_obsolete_entries failure"
3379 " -- OLD or OBSOLETE method found -- class: %s",
3380 ik->signature_name()));
3381 ik->constants()->cache()->dump_cache();
3382 }
3383 no_old_methods = false;
3384 }
3385
3386 if (!no_old_methods) {
3387 if (RC_TRACE_ENABLED(0x00004000)) {
3388 dump_methods();
3389 } else {
3390 tty->print_cr("INFO: use the '-XX:TraceRedefineClasses=16384' option "
3391 "to see more info about the following guarantee() failure.");
3392 }
3393 guarantee(false, "OLD and/or OBSOLETE method(s) found");
3394 }
3395 }
3396 }
3397
3398 void VM_RedefineClasses::dump_methods() {
3399 int j;
3400 RC_TRACE(0x00004000, ("_old_methods --"));
3401 for (j = 0; j < _old_methods->length(); ++j) {
3402 Method* m = _old_methods->at(j);
3403 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
3404 m->access_flags().print_on(tty);
3405 tty->print(" -- ");
3406 m->print_name(tty);
3407 tty->cr();
3408 }
3409 RC_TRACE(0x00004000, ("_new_methods --"));
3410 for (j = 0; j < _new_methods->length(); ++j) {
3411 Method* m = _new_methods->at(j);
3412 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
3413 m->access_flags().print_on(tty);
3414 tty->print(" -- ");
3415 m->print_name(tty);
3416 tty->cr();
3417 }
3418 RC_TRACE(0x00004000, ("_matching_(old/new)_methods --"));
3419 for (j = 0; j < _matching_methods_length; ++j) {
3420 Method* m = _matching_old_methods[j];
3421 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
3422 m->access_flags().print_on(tty);
3423 tty->print(" -- ");
3424 m->print_name(tty);
3425 tty->cr();
3426 m = _matching_new_methods[j];
3427 RC_TRACE_NO_CR(0x00004000, (" (%5d) ", m->vtable_index()));
3428 m->access_flags().print_on(tty);
3429 tty->cr();
3430 }
3431 RC_TRACE(0x00004000, ("_deleted_methods --"));
3432 for (j = 0; j < _deleted_methods_length; ++j) {
3433 Method* m = _deleted_methods[j];
3434 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
3435 m->access_flags().print_on(tty);
3436 tty->print(" -- ");
3437 m->print_name(tty);
3438 tty->cr();
3439 }
3440 RC_TRACE(0x00004000, ("_added_methods --"));
3441 for (j = 0; j < _added_methods_length; ++j) {
3442 Method* m = _added_methods[j];
3443 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
3444 m->access_flags().print_on(tty);
3445 tty->print(" -- ");
3446 m->print_name(tty);
3447 tty->cr();
3448 }
3449 }