1 /*
2 * Copyright (c) 2003, 2016, 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 "aot/aotLoader.hpp"
27 #include "classfile/classFileStream.hpp"
28 #include "classfile/metadataOnStackMark.hpp"
29 #include "classfile/systemDictionary.hpp"
30 #include "classfile/verifier.hpp"
31 #include "code/codeCache.hpp"
32 #include "compiler/compileBroker.hpp"
33 #include "gc/shared/gcLocker.hpp"
34 #include "interpreter/oopMapCache.hpp"
35 #include "interpreter/rewriter.hpp"
36 #include "logging/logStream.hpp"
37 #include "memory/metadataFactory.hpp"
38 #include "memory/metaspaceShared.hpp"
39 #include "memory/resourceArea.hpp"
40 #include "memory/universe.inline.hpp"
41 #include "oops/fieldStreams.hpp"
42 #include "oops/klassVtable.hpp"
43 #include "oops/oop.inline.hpp"
44 #include "prims/jvmtiImpl.hpp"
45 #include "prims/jvmtiRedefineClasses.hpp"
46 #include "prims/methodComparator.hpp"
47 #include "runtime/deoptimization.hpp"
48 #include "runtime/relocator.hpp"
49 #include "utilities/bitMap.inline.hpp"
50 #include "utilities/events.hpp"
51
52 Array<Method*>* VM_RedefineClasses::_old_methods = NULL;
53 Array<Method*>* VM_RedefineClasses::_new_methods = NULL;
54 Method** VM_RedefineClasses::_matching_old_methods = NULL;
55 Method** VM_RedefineClasses::_matching_new_methods = NULL;
56 Method** VM_RedefineClasses::_deleted_methods = NULL;
57 Method** VM_RedefineClasses::_added_methods = NULL;
58 int VM_RedefineClasses::_matching_methods_length = 0;
59 int VM_RedefineClasses::_deleted_methods_length = 0;
60 int VM_RedefineClasses::_added_methods_length = 0;
61 Klass* VM_RedefineClasses::_the_class_oop = NULL;
62
63
64 VM_RedefineClasses::VM_RedefineClasses(jint class_count,
65 const jvmtiClassDefinition *class_defs,
66 JvmtiClassLoadKind class_load_kind) {
67 _class_count = class_count;
68 _class_defs = class_defs;
69 _class_load_kind = class_load_kind;
70 _res = JVMTI_ERROR_NONE;
71 }
72
73 static inline InstanceKlass* get_ik(jclass def) {
74 oop mirror = JNIHandles::resolve_non_null(def);
75 return InstanceKlass::cast(java_lang_Class::as_Klass(mirror));
76 }
77
78 // If any of the classes are being redefined, wait
79 // Parallel constant pool merging leads to indeterminate constant pools.
80 void VM_RedefineClasses::lock_classes() {
81 MutexLocker ml(RedefineClasses_lock);
82 bool has_redefined;
83 do {
84 has_redefined = false;
85 // Go through classes each time until none are being redefined.
86 for (int i = 0; i < _class_count; i++) {
87 if (get_ik(_class_defs[i].klass)->is_being_redefined()) {
88 RedefineClasses_lock->wait();
89 has_redefined = true;
90 break; // for loop
91 }
92 }
93 } while (has_redefined);
94 for (int i = 0; i < _class_count; i++) {
95 get_ik(_class_defs[i].klass)->set_is_being_redefined(true);
96 }
97 RedefineClasses_lock->notify_all();
98 }
99
100 void VM_RedefineClasses::unlock_classes() {
101 MutexLocker ml(RedefineClasses_lock);
102 for (int i = 0; i < _class_count; i++) {
103 assert(get_ik(_class_defs[i].klass)->is_being_redefined(),
104 "should be being redefined to get here");
105 get_ik(_class_defs[i].klass)->set_is_being_redefined(false);
106 }
107 RedefineClasses_lock->notify_all();
108 }
109
110 bool VM_RedefineClasses::doit_prologue() {
111 if (_class_count == 0) {
112 _res = JVMTI_ERROR_NONE;
113 return false;
114 }
115 if (_class_defs == NULL) {
116 _res = JVMTI_ERROR_NULL_POINTER;
117 return false;
118 }
119 for (int i = 0; i < _class_count; i++) {
120 if (_class_defs[i].klass == NULL) {
121 _res = JVMTI_ERROR_INVALID_CLASS;
122 return false;
123 }
124 if (_class_defs[i].class_byte_count == 0) {
125 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT;
126 return false;
127 }
128 if (_class_defs[i].class_bytes == NULL) {
129 _res = JVMTI_ERROR_NULL_POINTER;
130 return false;
131 }
132
133 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass);
134 // classes for primitives and arrays and vm anonymous classes cannot be redefined
135 // check here so following code can assume these classes are InstanceKlass
136 if (!is_modifiable_class(mirror)) {
137 _res = JVMTI_ERROR_UNMODIFIABLE_CLASS;
138 return false;
139 }
140 }
141
142 // Start timer after all the sanity checks; not quite accurate, but
143 // better than adding a bunch of stop() calls.
144 if (log_is_enabled(Info, redefine, class, timer)) {
145 _timer_vm_op_prologue.start();
146 }
147
148 lock_classes();
149 // We first load new class versions in the prologue, because somewhere down the
150 // call chain it is required that the current thread is a Java thread.
151 _res = load_new_class_versions(Thread::current());
152 if (_res != JVMTI_ERROR_NONE) {
153 // free any successfully created classes, since none are redefined
154 for (int i = 0; i < _class_count; i++) {
155 if (_scratch_classes[i] != NULL) {
156 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data();
157 // Free the memory for this class at class unloading time. Not before
158 // because CMS might think this is still live.
159 cld->add_to_deallocate_list(InstanceKlass::cast(_scratch_classes[i]));
160 }
161 }
162 // Free os::malloc allocated memory in load_new_class_version.
163 os::free(_scratch_classes);
164 _timer_vm_op_prologue.stop();
165 unlock_classes();
166 return false;
167 }
168
169 _timer_vm_op_prologue.stop();
170 return true;
171 }
172
173 void VM_RedefineClasses::doit() {
174 Thread *thread = Thread::current();
175
176 if (UseSharedSpaces) {
177 // Sharing is enabled so we remap the shared readonly space to
178 // shared readwrite, private just in case we need to redefine
179 // a shared class. We do the remap during the doit() phase of
180 // the safepoint to be safer.
181 if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) {
182 log_info(redefine, class, load)("failed to remap shared readonly space to readwrite, private");
183 _res = JVMTI_ERROR_INTERNAL;
184 return;
185 }
186 }
187
188 // Mark methods seen on stack and everywhere else so old methods are not
189 // cleaned up if they're on the stack.
190 MetadataOnStackMark md_on_stack(true);
191 HandleMark hm(thread); // make sure any handles created are deleted
192 // before the stack walk again.
193
194 for (int i = 0; i < _class_count; i++) {
195 redefine_single_class(_class_defs[i].klass, _scratch_classes[i], thread);
196 }
197
198 // Clean out MethodData pointing to old Method*
199 // Have to do this after all classes are redefined and all methods that
200 // are redefined are marked as old.
201 MethodDataCleaner clean_weak_method_links;
202 ClassLoaderDataGraph::classes_do(&clean_weak_method_links);
203
204 // Disable any dependent concurrent compilations
205 SystemDictionary::notice_modification();
206
207 // Set flag indicating that some invariants are no longer true.
208 // See jvmtiExport.hpp for detailed explanation.
209 JvmtiExport::set_has_redefined_a_class();
210
211 // check_class() is optionally called for product bits, but is
212 // always called for non-product bits.
213 #ifdef PRODUCT
214 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
215 #endif
216 log_trace(redefine, class, obsolete, metadata)("calling check_class");
217 CheckClass check_class(thread);
218 ClassLoaderDataGraph::classes_do(&check_class);
219 #ifdef PRODUCT
220 }
221 #endif
222 }
223
224 void VM_RedefineClasses::doit_epilogue() {
225 unlock_classes();
226
227 // Free os::malloc allocated memory.
228 os::free(_scratch_classes);
229
230 // Reset the_class_oop to null for error printing.
231 _the_class_oop = NULL;
232
233 if (log_is_enabled(Info, redefine, class, timer)) {
234 // Used to have separate timers for "doit" and "all", but the timer
235 // overhead skewed the measurements.
236 jlong doit_time = _timer_rsc_phase1.milliseconds() +
237 _timer_rsc_phase2.milliseconds();
238 jlong all_time = _timer_vm_op_prologue.milliseconds() + doit_time;
239
240 log_info(redefine, class, timer)
241 ("vm_op: all=" UINT64_FORMAT " prologue=" UINT64_FORMAT " doit=" UINT64_FORMAT,
242 all_time, _timer_vm_op_prologue.milliseconds(), doit_time);
243 log_info(redefine, class, timer)
244 ("redefine_single_class: phase1=" UINT64_FORMAT " phase2=" UINT64_FORMAT,
245 _timer_rsc_phase1.milliseconds(), _timer_rsc_phase2.milliseconds());
246 }
247 }
248
249 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) {
250 // classes for primitives cannot be redefined
251 if (java_lang_Class::is_primitive(klass_mirror)) {
252 return false;
253 }
254 Klass* k = java_lang_Class::as_Klass(klass_mirror);
255 // classes for arrays cannot be redefined
256 if (k == NULL || !k->is_instance_klass()) {
257 return false;
258 }
259
260 // Cannot redefine or retransform an anonymous class.
261 if (InstanceKlass::cast(k)->is_anonymous()) {
262 return false;
263 }
264 return true;
265 }
266
267 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p
268 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For
269 // direct CP entries, there is just the current entry to append. For
270 // indirect and double-indirect CP entries, there are zero or more
271 // referenced CP entries along with the current entry to append.
272 // Indirect and double-indirect CP entries are handled by recursive
273 // calls to append_entry() as needed. The referenced CP entries are
274 // always appended to *merge_cp_p before the referee CP entry. These
275 // referenced CP entries may already exist in *merge_cp_p in which case
276 // there is nothing extra to append and only the current entry is
277 // appended.
278 void VM_RedefineClasses::append_entry(const constantPoolHandle& scratch_cp,
279 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p,
280 TRAPS) {
281
282 // append is different depending on entry tag type
283 switch (scratch_cp->tag_at(scratch_i).value()) {
284
285 // The old verifier is implemented outside the VM. It loads classes,
286 // but does not resolve constant pool entries directly so we never
287 // see Class entries here with the old verifier. Similarly the old
288 // verifier does not like Class entries in the input constant pool.
289 // The split-verifier is implemented in the VM so it can optionally
290 // and directly resolve constant pool entries to load classes. The
291 // split-verifier can accept either Class entries or UnresolvedClass
292 // entries in the input constant pool. We revert the appended copy
293 // back to UnresolvedClass so that either verifier will be happy
294 // with the constant pool entry.
295 case JVM_CONSTANT_Class:
296 {
297 // revert the copy to JVM_CONSTANT_UnresolvedClass
298 (*merge_cp_p)->unresolved_klass_at_put(*merge_cp_length_p,
299 scratch_cp->klass_name_at(scratch_i));
300
301 if (scratch_i != *merge_cp_length_p) {
302 // The new entry in *merge_cp_p is at a different index than
303 // the new entry in scratch_cp so we need to map the index values.
304 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
305 }
306 (*merge_cp_length_p)++;
307 } break;
308
309 // these are direct CP entries so they can be directly appended,
310 // but double and long take two constant pool entries
311 case JVM_CONSTANT_Double: // fall through
312 case JVM_CONSTANT_Long:
313 {
314 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
315 THREAD);
316
317 if (scratch_i != *merge_cp_length_p) {
318 // The new entry in *merge_cp_p is at a different index than
319 // the new entry in scratch_cp so we need to map the index values.
320 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
321 }
322 (*merge_cp_length_p) += 2;
323 } break;
324
325 // these are direct CP entries so they can be directly appended
326 case JVM_CONSTANT_Float: // fall through
327 case JVM_CONSTANT_Integer: // fall through
328 case JVM_CONSTANT_Utf8: // fall through
329
330 // This was an indirect CP entry, but it has been changed into
331 // Symbol*s so this entry can be directly appended.
332 case JVM_CONSTANT_String: // fall through
333
334 // These were indirect CP entries, but they have been changed into
335 // Symbol*s so these entries can be directly appended.
336 case JVM_CONSTANT_UnresolvedClass: // fall through
337 {
338 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
339 THREAD);
340
341 if (scratch_i != *merge_cp_length_p) {
342 // The new entry in *merge_cp_p is at a different index than
343 // the new entry in scratch_cp so we need to map the index values.
344 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
345 }
346 (*merge_cp_length_p)++;
347 } break;
348
349 // this is an indirect CP entry so it needs special handling
350 case JVM_CONSTANT_NameAndType:
351 {
352 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i);
353 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p,
354 merge_cp_length_p, THREAD);
355
356 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i);
357 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i,
358 merge_cp_p, merge_cp_length_p,
359 THREAD);
360
361 // If the referenced entries already exist in *merge_cp_p, then
362 // both new_name_ref_i and new_signature_ref_i will both be 0.
363 // In that case, all we are appending is the current entry.
364 if (new_name_ref_i != name_ref_i) {
365 log_trace(redefine, class, constantpool)
366 ("NameAndType entry@%d name_ref_index change: %d to %d",
367 *merge_cp_length_p, name_ref_i, new_name_ref_i);
368 }
369 if (new_signature_ref_i != signature_ref_i) {
370 log_trace(redefine, class, constantpool)
371 ("NameAndType entry@%d signature_ref_index change: %d to %d",
372 *merge_cp_length_p, signature_ref_i, new_signature_ref_i);
373 }
374
375 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p,
376 new_name_ref_i, new_signature_ref_i);
377 if (scratch_i != *merge_cp_length_p) {
378 // The new entry in *merge_cp_p is at a different index than
379 // the new entry in scratch_cp so we need to map the index values.
380 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
381 }
382 (*merge_cp_length_p)++;
383 } break;
384
385 // this is a double-indirect CP entry so it needs special handling
386 case JVM_CONSTANT_Fieldref: // fall through
387 case JVM_CONSTANT_InterfaceMethodref: // fall through
388 case JVM_CONSTANT_Methodref:
389 {
390 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i);
391 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i,
392 merge_cp_p, merge_cp_length_p, THREAD);
393
394 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i);
395 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i,
396 merge_cp_p, merge_cp_length_p, THREAD);
397
398 const char *entry_name = NULL;
399 switch (scratch_cp->tag_at(scratch_i).value()) {
400 case JVM_CONSTANT_Fieldref:
401 entry_name = "Fieldref";
402 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i,
403 new_name_and_type_ref_i);
404 break;
405 case JVM_CONSTANT_InterfaceMethodref:
406 entry_name = "IFMethodref";
407 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p,
408 new_klass_ref_i, new_name_and_type_ref_i);
409 break;
410 case JVM_CONSTANT_Methodref:
411 entry_name = "Methodref";
412 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i,
413 new_name_and_type_ref_i);
414 break;
415 default:
416 guarantee(false, "bad switch");
417 break;
418 }
419
420 if (klass_ref_i != new_klass_ref_i) {
421 log_trace(redefine, class, constantpool)
422 ("%s entry@%d class_index changed: %d to %d", entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i);
423 }
424 if (name_and_type_ref_i != new_name_and_type_ref_i) {
425 log_trace(redefine, class, constantpool)
426 ("%s entry@%d name_and_type_index changed: %d to %d",
427 entry_name, *merge_cp_length_p, name_and_type_ref_i, new_name_and_type_ref_i);
428 }
429
430 if (scratch_i != *merge_cp_length_p) {
431 // The new entry in *merge_cp_p is at a different index than
432 // the new entry in scratch_cp so we need to map the index values.
433 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
434 }
435 (*merge_cp_length_p)++;
436 } break;
437
438 // this is an indirect CP entry so it needs special handling
439 case JVM_CONSTANT_MethodType:
440 {
441 int ref_i = scratch_cp->method_type_index_at(scratch_i);
442 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
443 merge_cp_length_p, THREAD);
444 if (new_ref_i != ref_i) {
445 log_trace(redefine, class, constantpool)
446 ("MethodType entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i);
447 }
448 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i);
449 if (scratch_i != *merge_cp_length_p) {
450 // The new entry in *merge_cp_p is at a different index than
451 // the new entry in scratch_cp so we need to map the index values.
452 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
453 }
454 (*merge_cp_length_p)++;
455 } break;
456
457 // this is an indirect CP entry so it needs special handling
458 case JVM_CONSTANT_MethodHandle:
459 {
460 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i);
461 int ref_i = scratch_cp->method_handle_index_at(scratch_i);
462 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
463 merge_cp_length_p, THREAD);
464 if (new_ref_i != ref_i) {
465 log_trace(redefine, class, constantpool)
466 ("MethodHandle entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i);
467 }
468 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i);
469 if (scratch_i != *merge_cp_length_p) {
470 // The new entry in *merge_cp_p is at a different index than
471 // the new entry in scratch_cp so we need to map the index values.
472 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
473 }
474 (*merge_cp_length_p)++;
475 } break;
476
477 // this is an indirect CP entry so it needs special handling
478 case JVM_CONSTANT_InvokeDynamic:
479 {
480 // Index of the bootstrap specifier in the operands array
481 int old_bs_i = scratch_cp->invoke_dynamic_bootstrap_specifier_index(scratch_i);
482 int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p,
483 merge_cp_length_p, THREAD);
484 // The bootstrap method NameAndType_info index
485 int old_ref_i = scratch_cp->invoke_dynamic_name_and_type_ref_index_at(scratch_i);
486 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
487 merge_cp_length_p, THREAD);
488 if (new_bs_i != old_bs_i) {
489 log_trace(redefine, class, constantpool)
490 ("InvokeDynamic entry@%d bootstrap_method_attr_index change: %d to %d",
491 *merge_cp_length_p, old_bs_i, new_bs_i);
492 }
493 if (new_ref_i != old_ref_i) {
494 log_trace(redefine, class, constantpool)
495 ("InvokeDynamic entry@%d name_and_type_index change: %d to %d", *merge_cp_length_p, old_ref_i, new_ref_i);
496 }
497
498 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
499 if (scratch_i != *merge_cp_length_p) {
500 // The new entry in *merge_cp_p is at a different index than
501 // the new entry in scratch_cp so we need to map the index values.
502 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
503 }
504 (*merge_cp_length_p)++;
505 } break;
506
507 // At this stage, Class or UnresolvedClass could be here, but not
508 // ClassIndex
509 case JVM_CONSTANT_ClassIndex: // fall through
510
511 // Invalid is used as the tag for the second constant pool entry
512 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
513 // not be seen by itself.
514 case JVM_CONSTANT_Invalid: // fall through
515
516 // At this stage, String could be here, but not StringIndex
517 case JVM_CONSTANT_StringIndex: // fall through
518
519 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be
520 // here
521 case JVM_CONSTANT_UnresolvedClassInError: // fall through
522
523 default:
524 {
525 // leave a breadcrumb
526 jbyte bad_value = scratch_cp->tag_at(scratch_i).value();
527 ShouldNotReachHere();
528 } break;
529 } // end switch tag value
530 } // end append_entry()
531
532
533 int VM_RedefineClasses::find_or_append_indirect_entry(const constantPoolHandle& scratch_cp,
534 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
535
536 int new_ref_i = ref_i;
537 bool match = (ref_i < *merge_cp_length_p) &&
538 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i, THREAD);
539
540 if (!match) {
541 // forward reference in *merge_cp_p or not a direct match
542 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p, THREAD);
543 if (found_i != 0) {
544 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree");
545 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry.
546 new_ref_i = found_i;
547 map_index(scratch_cp, ref_i, found_i);
548 } else {
549 // no match found so we have to append this entry to *merge_cp_p
550 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p, THREAD);
551 // The above call to append_entry() can only append one entry
552 // so the post call query of *merge_cp_length_p is only for
553 // the sake of consistency.
554 new_ref_i = *merge_cp_length_p - 1;
555 }
556 }
557
558 return new_ref_i;
559 } // end find_or_append_indirect_entry()
560
561
562 // Append a bootstrap specifier into the merge_cp operands that is semantically equal
563 // to the scratch_cp operands bootstrap specifier passed by the old_bs_i index.
564 // Recursively append new merge_cp entries referenced by the new bootstrap specifier.
565 void VM_RedefineClasses::append_operand(const constantPoolHandle& scratch_cp, int old_bs_i,
566 constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
567
568 int old_ref_i = scratch_cp->operand_bootstrap_method_ref_index_at(old_bs_i);
569 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
570 merge_cp_length_p, THREAD);
571 if (new_ref_i != old_ref_i) {
572 log_trace(redefine, class, constantpool)
573 ("operands entry@%d bootstrap method ref_index change: %d to %d", _operands_cur_length, old_ref_i, new_ref_i);
574 }
575
576 Array<u2>* merge_ops = (*merge_cp_p)->operands();
577 int new_bs_i = _operands_cur_length;
578 // We have _operands_cur_length == 0 when the merge_cp operands is empty yet.
579 // However, the operand_offset_at(0) was set in the extend_operands() call.
580 int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0)
581 : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1);
582 int argc = scratch_cp->operand_argument_count_at(old_bs_i);
583
584 ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base);
585 merge_ops->at_put(new_base++, new_ref_i);
586 merge_ops->at_put(new_base++, argc);
587
588 for (int i = 0; i < argc; i++) {
589 int old_arg_ref_i = scratch_cp->operand_argument_index_at(old_bs_i, i);
590 int new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p,
591 merge_cp_length_p, THREAD);
592 merge_ops->at_put(new_base++, new_arg_ref_i);
593 if (new_arg_ref_i != old_arg_ref_i) {
594 log_trace(redefine, class, constantpool)
595 ("operands entry@%d bootstrap method argument ref_index change: %d to %d",
596 _operands_cur_length, old_arg_ref_i, new_arg_ref_i);
597 }
598 }
599 if (old_bs_i != _operands_cur_length) {
600 // The bootstrap specifier in *merge_cp_p is at a different index than
601 // that in scratch_cp so we need to map the index values.
602 map_operand_index(old_bs_i, new_bs_i);
603 }
604 _operands_cur_length++;
605 } // end append_operand()
606
607
608 int VM_RedefineClasses::find_or_append_operand(const constantPoolHandle& scratch_cp,
609 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
610
611 int new_bs_i = old_bs_i; // bootstrap specifier index
612 bool match = (old_bs_i < _operands_cur_length) &&
613 scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i, THREAD);
614
615 if (!match) {
616 // forward reference in *merge_cp_p or not a direct match
617 int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p,
618 _operands_cur_length, THREAD);
619 if (found_i != -1) {
620 guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree");
621 // found a matching operand somewhere else in *merge_cp_p so just need a mapping
622 new_bs_i = found_i;
623 map_operand_index(old_bs_i, found_i);
624 } else {
625 // no match found so we have to append this bootstrap specifier to *merge_cp_p
626 append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p, THREAD);
627 new_bs_i = _operands_cur_length - 1;
628 }
629 }
630 return new_bs_i;
631 } // end find_or_append_operand()
632
633
634 void VM_RedefineClasses::finalize_operands_merge(const constantPoolHandle& merge_cp, TRAPS) {
635 if (merge_cp->operands() == NULL) {
636 return;
637 }
638 // Shrink the merge_cp operands
639 merge_cp->shrink_operands(_operands_cur_length, CHECK);
640
641 if (log_is_enabled(Trace, redefine, class, constantpool)) {
642 // don't want to loop unless we are tracing
643 int count = 0;
644 for (int i = 1; i < _operands_index_map_p->length(); i++) {
645 int value = _operands_index_map_p->at(i);
646 if (value != -1) {
647 log_trace(redefine, class, constantpool)("operands_index_map[%d]: old=%d new=%d", count, i, value);
648 count++;
649 }
650 }
651 }
652 // Clean-up
653 _operands_index_map_p = NULL;
654 _operands_cur_length = 0;
655 _operands_index_map_count = 0;
656 } // end finalize_operands_merge()
657
658
659 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions(
660 instanceKlassHandle the_class,
661 instanceKlassHandle scratch_class) {
662 int i;
663
664 // Check superclasses, or rather their names, since superclasses themselves can be
665 // requested to replace.
666 // Check for NULL superclass first since this might be java.lang.Object
667 if (the_class->super() != scratch_class->super() &&
668 (the_class->super() == NULL || scratch_class->super() == NULL ||
669 the_class->super()->name() !=
670 scratch_class->super()->name())) {
671 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
672 }
673
674 // Check if the number, names and order of directly implemented interfaces are the same.
675 // I think in principle we should just check if the sets of names of directly implemented
676 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the
677 // .java file, also changes in .class file) should not matter. However, comparing sets is
678 // technically a bit more difficult, and, more importantly, I am not sure at present that the
679 // order of interfaces does not matter on the implementation level, i.e. that the VM does not
680 // rely on it somewhere.
681 Array<Klass*>* k_interfaces = the_class->local_interfaces();
682 Array<Klass*>* k_new_interfaces = scratch_class->local_interfaces();
683 int n_intfs = k_interfaces->length();
684 if (n_intfs != k_new_interfaces->length()) {
685 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
686 }
687 for (i = 0; i < n_intfs; i++) {
688 if (k_interfaces->at(i)->name() !=
689 k_new_interfaces->at(i)->name()) {
690 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
691 }
692 }
693
694 // Check whether class is in the error init state.
695 if (the_class->is_in_error_state()) {
696 // TBD #5057930: special error code is needed in 1.6
697 return JVMTI_ERROR_INVALID_CLASS;
698 }
699
700 // Check whether class modifiers are the same.
701 jushort old_flags = (jushort) the_class->access_flags().get_flags();
702 jushort new_flags = (jushort) scratch_class->access_flags().get_flags();
703 if (old_flags != new_flags) {
704 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED;
705 }
706
707 // Check if the number, names, types and order of fields declared in these classes
708 // are the same.
709 JavaFieldStream old_fs(the_class);
710 JavaFieldStream new_fs(scratch_class);
711 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) {
712 // access
713 old_flags = old_fs.access_flags().as_short();
714 new_flags = new_fs.access_flags().as_short();
715 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) {
716 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
717 }
718 // offset
719 if (old_fs.offset() != new_fs.offset()) {
720 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
721 }
722 // name and signature
723 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index());
724 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index());
725 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index());
726 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index());
727 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) {
728 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
729 }
730 }
731
732 // If both streams aren't done then we have a differing number of
733 // fields.
734 if (!old_fs.done() || !new_fs.done()) {
735 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
736 }
737
738 // Do a parallel walk through the old and new methods. Detect
739 // cases where they match (exist in both), have been added in
740 // the new methods, or have been deleted (exist only in the
741 // old methods). The class file parser places methods in order
742 // by method name, but does not order overloaded methods by
743 // signature. In order to determine what fate befell the methods,
744 // this code places the overloaded new methods that have matching
745 // old methods in the same order as the old methods and places
746 // new overloaded methods at the end of overloaded methods of
747 // that name. The code for this order normalization is adapted
748 // from the algorithm used in InstanceKlass::find_method().
749 // Since we are swapping out of order entries as we find them,
750 // we only have to search forward through the overloaded methods.
751 // Methods which are added and have the same name as an existing
752 // method (but different signature) will be put at the end of
753 // the methods with that name, and the name mismatch code will
754 // handle them.
755 Array<Method*>* k_old_methods(the_class->methods());
756 Array<Method*>* k_new_methods(scratch_class->methods());
757 int n_old_methods = k_old_methods->length();
758 int n_new_methods = k_new_methods->length();
759 Thread* thread = Thread::current();
760
761 int ni = 0;
762 int oi = 0;
763 while (true) {
764 Method* k_old_method;
765 Method* k_new_method;
766 enum { matched, added, deleted, undetermined } method_was = undetermined;
767
768 if (oi >= n_old_methods) {
769 if (ni >= n_new_methods) {
770 break; // we've looked at everything, done
771 }
772 // New method at the end
773 k_new_method = k_new_methods->at(ni);
774 method_was = added;
775 } else if (ni >= n_new_methods) {
776 // Old method, at the end, is deleted
777 k_old_method = k_old_methods->at(oi);
778 method_was = deleted;
779 } else {
780 // There are more methods in both the old and new lists
781 k_old_method = k_old_methods->at(oi);
782 k_new_method = k_new_methods->at(ni);
783 if (k_old_method->name() != k_new_method->name()) {
784 // Methods are sorted by method name, so a mismatch means added
785 // or deleted
786 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) {
787 method_was = added;
788 } else {
789 method_was = deleted;
790 }
791 } else if (k_old_method->signature() == k_new_method->signature()) {
792 // Both the name and signature match
793 method_was = matched;
794 } else {
795 // The name matches, but the signature doesn't, which means we have to
796 // search forward through the new overloaded methods.
797 int nj; // outside the loop for post-loop check
798 for (nj = ni + 1; nj < n_new_methods; nj++) {
799 Method* m = k_new_methods->at(nj);
800 if (k_old_method->name() != m->name()) {
801 // reached another method name so no more overloaded methods
802 method_was = deleted;
803 break;
804 }
805 if (k_old_method->signature() == m->signature()) {
806 // found a match so swap the methods
807 k_new_methods->at_put(ni, m);
808 k_new_methods->at_put(nj, k_new_method);
809 k_new_method = m;
810 method_was = matched;
811 break;
812 }
813 }
814
815 if (nj >= n_new_methods) {
816 // reached the end without a match; so method was deleted
817 method_was = deleted;
818 }
819 }
820 }
821
822 switch (method_was) {
823 case matched:
824 // methods match, be sure modifiers do too
825 old_flags = (jushort) k_old_method->access_flags().get_flags();
826 new_flags = (jushort) k_new_method->access_flags().get_flags();
827 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) {
828 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED;
829 }
830 {
831 u2 new_num = k_new_method->method_idnum();
832 u2 old_num = k_old_method->method_idnum();
833 if (new_num != old_num) {
834 Method* idnum_owner = scratch_class->method_with_idnum(old_num);
835 if (idnum_owner != NULL) {
836 // There is already a method assigned this idnum -- switch them
837 // Take current and original idnum from the new_method
838 idnum_owner->set_method_idnum(new_num);
839 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum());
840 }
841 // Take current and original idnum from the old_method
842 k_new_method->set_method_idnum(old_num);
843 k_new_method->set_orig_method_idnum(k_old_method->orig_method_idnum());
844 if (thread->has_pending_exception()) {
845 return JVMTI_ERROR_OUT_OF_MEMORY;
846 }
847 }
848 }
849 log_trace(redefine, class, normalize)
850 ("Method matched: new: %s [%d] == old: %s [%d]",
851 k_new_method->name_and_sig_as_C_string(), ni, k_old_method->name_and_sig_as_C_string(), oi);
852 // advance to next pair of methods
853 ++oi;
854 ++ni;
855 break;
856 case added:
857 // method added, see if it is OK
858 new_flags = (jushort) k_new_method->access_flags().get_flags();
859 if ((new_flags & JVM_ACC_PRIVATE) == 0
860 // hack: private should be treated as final, but alas
861 || (new_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
862 ) {
863 // new methods must be private
864 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
865 }
866 {
867 u2 num = the_class->next_method_idnum();
868 if (num == ConstMethod::UNSET_IDNUM) {
869 // cannot add any more methods
870 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
871 }
872 u2 new_num = k_new_method->method_idnum();
873 Method* idnum_owner = scratch_class->method_with_idnum(num);
874 if (idnum_owner != NULL) {
875 // There is already a method assigned this idnum -- switch them
876 // Take current and original idnum from the new_method
877 idnum_owner->set_method_idnum(new_num);
878 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum());
879 }
880 k_new_method->set_method_idnum(num);
881 k_new_method->set_orig_method_idnum(num);
882 if (thread->has_pending_exception()) {
883 return JVMTI_ERROR_OUT_OF_MEMORY;
884 }
885 }
886 log_trace(redefine, class, normalize)
887 ("Method added: new: %s [%d]", k_new_method->name_and_sig_as_C_string(), ni);
888 ++ni; // advance to next new method
889 break;
890 case deleted:
891 // method deleted, see if it is OK
892 old_flags = (jushort) k_old_method->access_flags().get_flags();
893 if ((old_flags & JVM_ACC_PRIVATE) == 0
894 // hack: private should be treated as final, but alas
895 || (old_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
896 ) {
897 // deleted methods must be private
898 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED;
899 }
900 log_trace(redefine, class, normalize)
901 ("Method deleted: old: %s [%d]", k_old_method->name_and_sig_as_C_string(), oi);
902 ++oi; // advance to next old method
903 break;
904 default:
905 ShouldNotReachHere();
906 }
907 }
908
909 return JVMTI_ERROR_NONE;
910 }
911
912
913 // Find new constant pool index value for old constant pool index value
914 // by seaching the index map. Returns zero (0) if there is no mapped
915 // value for the old constant pool index.
916 int VM_RedefineClasses::find_new_index(int old_index) {
917 if (_index_map_count == 0) {
918 // map is empty so nothing can be found
919 return 0;
920 }
921
922 if (old_index < 1 || old_index >= _index_map_p->length()) {
923 // The old_index is out of range so it is not mapped. This should
924 // not happen in regular constant pool merging use, but it can
925 // happen if a corrupt annotation is processed.
926 return 0;
927 }
928
929 int value = _index_map_p->at(old_index);
930 if (value == -1) {
931 // the old_index is not mapped
932 return 0;
933 }
934
935 return value;
936 } // end find_new_index()
937
938
939 // Find new bootstrap specifier index value for old bootstrap specifier index
940 // value by seaching the index map. Returns unused index (-1) if there is
941 // no mapped value for the old bootstrap specifier index.
942 int VM_RedefineClasses::find_new_operand_index(int old_index) {
943 if (_operands_index_map_count == 0) {
944 // map is empty so nothing can be found
945 return -1;
946 }
947
948 if (old_index == -1 || old_index >= _operands_index_map_p->length()) {
949 // The old_index is out of range so it is not mapped.
950 // This should not happen in regular constant pool merging use.
951 return -1;
952 }
953
954 int value = _operands_index_map_p->at(old_index);
955 if (value == -1) {
956 // the old_index is not mapped
957 return -1;
958 }
959
960 return value;
961 } // end find_new_operand_index()
962
963
964 // Returns true if the current mismatch is due to a resolved/unresolved
965 // class pair. Otherwise, returns false.
966 bool VM_RedefineClasses::is_unresolved_class_mismatch(const constantPoolHandle& cp1,
967 int index1, const constantPoolHandle& cp2, int index2) {
968
969 jbyte t1 = cp1->tag_at(index1).value();
970 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) {
971 return false; // wrong entry type; not our special case
972 }
973
974 jbyte t2 = cp2->tag_at(index2).value();
975 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) {
976 return false; // wrong entry type; not our special case
977 }
978
979 if (t1 == t2) {
980 return false; // not a mismatch; not our special case
981 }
982
983 char *s1 = cp1->klass_name_at(index1)->as_C_string();
984 char *s2 = cp2->klass_name_at(index2)->as_C_string();
985 if (strcmp(s1, s2) != 0) {
986 return false; // strings don't match; not our special case
987 }
988
989 return true; // made it through the gauntlet; this is our special case
990 } // end is_unresolved_class_mismatch()
991
992
993 jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) {
994
995 // For consistency allocate memory using os::malloc wrapper.
996 _scratch_classes = (Klass**)
997 os::malloc(sizeof(Klass*) * _class_count, mtClass);
998 if (_scratch_classes == NULL) {
999 return JVMTI_ERROR_OUT_OF_MEMORY;
1000 }
1001 // Zero initialize the _scratch_classes array.
1002 for (int i = 0; i < _class_count; i++) {
1003 _scratch_classes[i] = NULL;
1004 }
1005
1006 ResourceMark rm(THREAD);
1007
1008 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
1009 // state can only be NULL if the current thread is exiting which
1010 // should not happen since we're trying to do a RedefineClasses
1011 guarantee(state != NULL, "exiting thread calling load_new_class_versions");
1012 for (int i = 0; i < _class_count; i++) {
1013 // Create HandleMark so that any handles created while loading new class
1014 // versions are deleted. Constant pools are deallocated while merging
1015 // constant pools
1016 HandleMark hm(THREAD);
1017 instanceKlassHandle the_class(THREAD, get_ik(_class_defs[i].klass));
1018 Symbol* the_class_sym = the_class->name();
1019
1020 log_debug(redefine, class, load)
1021 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)",
1022 the_class->external_name(), _class_load_kind, os::available_memory() >> 10);
1023
1024 ClassFileStream st((u1*)_class_defs[i].class_bytes,
1025 _class_defs[i].class_byte_count,
1026 "__VM_RedefineClasses__",
1027 ClassFileStream::verify);
1028
1029 // Parse the stream.
1030 Handle the_class_loader(THREAD, the_class->class_loader());
1031 Handle protection_domain(THREAD, the_class->protection_domain());
1032 // Set redefined class handle in JvmtiThreadState class.
1033 // This redefined class is sent to agent event handler for class file
1034 // load hook event.
1035 state->set_class_being_redefined(&the_class, _class_load_kind);
1036
1037 Klass* k = SystemDictionary::parse_stream(the_class_sym,
1038 the_class_loader,
1039 protection_domain,
1040 &st,
1041 THREAD);
1042 // Clear class_being_redefined just to be sure.
1043 state->clear_class_being_redefined();
1044
1045 // TODO: if this is retransform, and nothing changed we can skip it
1046
1047 instanceKlassHandle scratch_class (THREAD, k);
1048
1049 // Need to clean up allocated InstanceKlass if there's an error so assign
1050 // the result here. Caller deallocates all the scratch classes in case of
1051 // an error.
1052 _scratch_classes[i] = k;
1053
1054 if (HAS_PENDING_EXCEPTION) {
1055 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1056 log_info(redefine, class, load, exceptions)("parse_stream exception: '%s'", ex_name->as_C_string());
1057 CLEAR_PENDING_EXCEPTION;
1058
1059 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) {
1060 return JVMTI_ERROR_UNSUPPORTED_VERSION;
1061 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) {
1062 return JVMTI_ERROR_INVALID_CLASS_FORMAT;
1063 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) {
1064 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION;
1065 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
1066 // The message will be "XXX (wrong name: YYY)"
1067 return JVMTI_ERROR_NAMES_DONT_MATCH;
1068 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1069 return JVMTI_ERROR_OUT_OF_MEMORY;
1070 } else { // Just in case more exceptions can be thrown..
1071 return JVMTI_ERROR_FAILS_VERIFICATION;
1072 }
1073 }
1074
1075 // Ensure class is linked before redefine
1076 if (!the_class->is_linked()) {
1077 the_class->link_class(THREAD);
1078 if (HAS_PENDING_EXCEPTION) {
1079 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1080 log_info(redefine, class, load, exceptions)("link_class exception: '%s'", ex_name->as_C_string());
1081 CLEAR_PENDING_EXCEPTION;
1082 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1083 return JVMTI_ERROR_OUT_OF_MEMORY;
1084 } else {
1085 return JVMTI_ERROR_INTERNAL;
1086 }
1087 }
1088 }
1089
1090 // Do the validity checks in compare_and_normalize_class_versions()
1091 // before verifying the byte codes. By doing these checks first, we
1092 // limit the number of functions that require redirection from
1093 // the_class to scratch_class. In particular, we don't have to
1094 // modify JNI GetSuperclass() and thus won't change its performance.
1095 jvmtiError res = compare_and_normalize_class_versions(the_class,
1096 scratch_class);
1097 if (res != JVMTI_ERROR_NONE) {
1098 return res;
1099 }
1100
1101 // verify what the caller passed us
1102 {
1103 // The bug 6214132 caused the verification to fail.
1104 // Information about the_class and scratch_class is temporarily
1105 // recorded into jvmtiThreadState. This data is used to redirect
1106 // the_class to scratch_class in the JVM_* functions called by the
1107 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed
1108 // description.
1109 RedefineVerifyMark rvm(&the_class, &scratch_class, state);
1110 Verifier::verify(
1111 scratch_class, Verifier::ThrowException, true, THREAD);
1112 }
1113
1114 if (HAS_PENDING_EXCEPTION) {
1115 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1116 log_info(redefine, class, load, exceptions)("verify_byte_codes exception: '%s'", ex_name->as_C_string());
1117 CLEAR_PENDING_EXCEPTION;
1118 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1119 return JVMTI_ERROR_OUT_OF_MEMORY;
1120 } else {
1121 // tell the caller the bytecodes are bad
1122 return JVMTI_ERROR_FAILS_VERIFICATION;
1123 }
1124 }
1125
1126 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD);
1127 if (HAS_PENDING_EXCEPTION) {
1128 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1129 log_info(redefine, class, load, exceptions)("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string());
1130 CLEAR_PENDING_EXCEPTION;
1131 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1132 return JVMTI_ERROR_OUT_OF_MEMORY;
1133 } else {
1134 return JVMTI_ERROR_INTERNAL;
1135 }
1136 }
1137
1138 if (VerifyMergedCPBytecodes) {
1139 // verify what we have done during constant pool merging
1140 {
1141 RedefineVerifyMark rvm(&the_class, &scratch_class, state);
1142 Verifier::verify(scratch_class, Verifier::ThrowException, true, THREAD);
1143 }
1144
1145 if (HAS_PENDING_EXCEPTION) {
1146 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1147 log_info(redefine, class, load, exceptions)
1148 ("verify_byte_codes post merge-CP exception: '%s'", ex_name->as_C_string());
1149 CLEAR_PENDING_EXCEPTION;
1150 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1151 return JVMTI_ERROR_OUT_OF_MEMORY;
1152 } else {
1153 // tell the caller that constant pool merging screwed up
1154 return JVMTI_ERROR_INTERNAL;
1155 }
1156 }
1157 }
1158
1159 Rewriter::rewrite(scratch_class, THREAD);
1160 if (!HAS_PENDING_EXCEPTION) {
1161 scratch_class->link_methods(THREAD);
1162 }
1163 if (HAS_PENDING_EXCEPTION) {
1164 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1165 log_info(redefine, class, load, exceptions)
1166 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string());
1167 CLEAR_PENDING_EXCEPTION;
1168 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1169 return JVMTI_ERROR_OUT_OF_MEMORY;
1170 } else {
1171 return JVMTI_ERROR_INTERNAL;
1172 }
1173 }
1174
1175 log_debug(redefine, class, load)
1176 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)", the_class->external_name(), os::available_memory() >> 10);
1177 }
1178
1179 return JVMTI_ERROR_NONE;
1180 }
1181
1182
1183 // Map old_index to new_index as needed. scratch_cp is only needed
1184 // for log calls.
1185 void VM_RedefineClasses::map_index(const constantPoolHandle& scratch_cp,
1186 int old_index, int new_index) {
1187 if (find_new_index(old_index) != 0) {
1188 // old_index is already mapped
1189 return;
1190 }
1191
1192 if (old_index == new_index) {
1193 // no mapping is needed
1194 return;
1195 }
1196
1197 _index_map_p->at_put(old_index, new_index);
1198 _index_map_count++;
1199
1200 log_trace(redefine, class, constantpool)
1201 ("mapped tag %d at index %d to %d", scratch_cp->tag_at(old_index).value(), old_index, new_index);
1202 } // end map_index()
1203
1204
1205 // Map old_index to new_index as needed.
1206 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) {
1207 if (find_new_operand_index(old_index) != -1) {
1208 // old_index is already mapped
1209 return;
1210 }
1211
1212 if (old_index == new_index) {
1213 // no mapping is needed
1214 return;
1215 }
1216
1217 _operands_index_map_p->at_put(old_index, new_index);
1218 _operands_index_map_count++;
1219
1220 log_trace(redefine, class, constantpool)("mapped bootstrap specifier at index %d to %d", old_index, new_index);
1221 } // end map_index()
1222
1223
1224 // Merge old_cp and scratch_cp and return the results of the merge via
1225 // merge_cp_p. The number of entries in *merge_cp_p is returned via
1226 // merge_cp_length_p. The entries in old_cp occupy the same locations
1227 // in *merge_cp_p. Also creates a map of indices from entries in
1228 // scratch_cp to the corresponding entry in *merge_cp_p. Index map
1229 // entries are only created for entries in scratch_cp that occupy a
1230 // different location in *merged_cp_p.
1231 bool VM_RedefineClasses::merge_constant_pools(const constantPoolHandle& old_cp,
1232 const constantPoolHandle& scratch_cp, constantPoolHandle *merge_cp_p,
1233 int *merge_cp_length_p, TRAPS) {
1234
1235 if (merge_cp_p == NULL) {
1236 assert(false, "caller must provide scratch constantPool");
1237 return false; // robustness
1238 }
1239 if (merge_cp_length_p == NULL) {
1240 assert(false, "caller must provide scratch CP length");
1241 return false; // robustness
1242 }
1243 // Worst case we need old_cp->length() + scratch_cp()->length(),
1244 // but the caller might be smart so make sure we have at least
1245 // the minimum.
1246 if ((*merge_cp_p)->length() < old_cp->length()) {
1247 assert(false, "merge area too small");
1248 return false; // robustness
1249 }
1250
1251 log_info(redefine, class, constantpool)("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(), scratch_cp->length());
1252
1253 {
1254 // Pass 0:
1255 // The old_cp is copied to *merge_cp_p; this means that any code
1256 // using old_cp does not have to change. This work looks like a
1257 // perfect fit for ConstantPool*::copy_cp_to(), but we need to
1258 // handle one special case:
1259 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass
1260 // This will make verification happy.
1261
1262 int old_i; // index into old_cp
1263
1264 // index zero (0) is not used in constantPools
1265 for (old_i = 1; old_i < old_cp->length(); old_i++) {
1266 // leave debugging crumb
1267 jbyte old_tag = old_cp->tag_at(old_i).value();
1268 switch (old_tag) {
1269 case JVM_CONSTANT_Class:
1270 case JVM_CONSTANT_UnresolvedClass:
1271 // revert the copy to JVM_CONSTANT_UnresolvedClass
1272 // May be resolving while calling this so do the same for
1273 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition)
1274 (*merge_cp_p)->unresolved_klass_at_put(old_i,
1275 old_cp->klass_name_at(old_i));
1276 break;
1277
1278 case JVM_CONSTANT_Double:
1279 case JVM_CONSTANT_Long:
1280 // just copy the entry to *merge_cp_p, but double and long take
1281 // two constant pool entries
1282 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1283 old_i++;
1284 break;
1285
1286 default:
1287 // just copy the entry to *merge_cp_p
1288 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1289 break;
1290 }
1291 } // end for each old_cp entry
1292
1293 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_0);
1294 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_0);
1295
1296 // We don't need to sanity check that *merge_cp_length_p is within
1297 // *merge_cp_p bounds since we have the minimum on-entry check above.
1298 (*merge_cp_length_p) = old_i;
1299 }
1300
1301 // merge_cp_len should be the same as old_cp->length() at this point
1302 // so this trace message is really a "warm-and-breathing" message.
1303 log_debug(redefine, class, constantpool)("after pass 0: merge_cp_len=%d", *merge_cp_length_p);
1304
1305 int scratch_i; // index into scratch_cp
1306 {
1307 // Pass 1a:
1308 // Compare scratch_cp entries to the old_cp entries that we have
1309 // already copied to *merge_cp_p. In this pass, we are eliminating
1310 // exact duplicates (matching entry at same index) so we only
1311 // compare entries in the common indice range.
1312 int increment = 1;
1313 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length());
1314 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) {
1315 switch (scratch_cp->tag_at(scratch_i).value()) {
1316 case JVM_CONSTANT_Double:
1317 case JVM_CONSTANT_Long:
1318 // double and long take two constant pool entries
1319 increment = 2;
1320 break;
1321
1322 default:
1323 increment = 1;
1324 break;
1325 }
1326
1327 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p,
1328 scratch_i, CHECK_0);
1329 if (match) {
1330 // found a match at the same index so nothing more to do
1331 continue;
1332 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i,
1333 *merge_cp_p, scratch_i)) {
1334 // The mismatch in compare_entry_to() above is because of a
1335 // resolved versus unresolved class entry at the same index
1336 // with the same string value. Since Pass 0 reverted any
1337 // class entries to unresolved class entries in *merge_cp_p,
1338 // we go with the unresolved class entry.
1339 continue;
1340 }
1341
1342 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p,
1343 CHECK_0);
1344 if (found_i != 0) {
1345 guarantee(found_i != scratch_i,
1346 "compare_entry_to() and find_matching_entry() do not agree");
1347
1348 // Found a matching entry somewhere else in *merge_cp_p so
1349 // just need a mapping entry.
1350 map_index(scratch_cp, scratch_i, found_i);
1351 continue;
1352 }
1353
1354 // The find_matching_entry() call above could fail to find a match
1355 // due to a resolved versus unresolved class or string entry situation
1356 // like we solved above with the is_unresolved_*_mismatch() calls.
1357 // However, we would have to call is_unresolved_*_mismatch() over
1358 // all of *merge_cp_p (potentially) and that doesn't seem to be
1359 // worth the time.
1360
1361 // No match found so we have to append this entry and any unique
1362 // referenced entries to *merge_cp_p.
1363 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1364 CHECK_0);
1365 }
1366 }
1367
1368 log_debug(redefine, class, constantpool)
1369 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1370 *merge_cp_length_p, scratch_i, _index_map_count);
1371
1372 if (scratch_i < scratch_cp->length()) {
1373 // Pass 1b:
1374 // old_cp is smaller than scratch_cp so there are entries in
1375 // scratch_cp that we have not yet processed. We take care of
1376 // those now.
1377 int increment = 1;
1378 for (; scratch_i < scratch_cp->length(); scratch_i += increment) {
1379 switch (scratch_cp->tag_at(scratch_i).value()) {
1380 case JVM_CONSTANT_Double:
1381 case JVM_CONSTANT_Long:
1382 // double and long take two constant pool entries
1383 increment = 2;
1384 break;
1385
1386 default:
1387 increment = 1;
1388 break;
1389 }
1390
1391 int found_i =
1392 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0);
1393 if (found_i != 0) {
1394 // Found a matching entry somewhere else in *merge_cp_p so
1395 // just need a mapping entry.
1396 map_index(scratch_cp, scratch_i, found_i);
1397 continue;
1398 }
1399
1400 // No match found so we have to append this entry and any unique
1401 // referenced entries to *merge_cp_p.
1402 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1403 CHECK_0);
1404 }
1405
1406 log_debug(redefine, class, constantpool)
1407 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1408 *merge_cp_length_p, scratch_i, _index_map_count);
1409 }
1410 finalize_operands_merge(*merge_cp_p, THREAD);
1411
1412 return true;
1413 } // end merge_constant_pools()
1414
1415
1416 // Scoped object to clean up the constant pool(s) created for merging
1417 class MergeCPCleaner {
1418 ClassLoaderData* _loader_data;
1419 ConstantPool* _cp;
1420 ConstantPool* _scratch_cp;
1421 public:
1422 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) :
1423 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {}
1424 ~MergeCPCleaner() {
1425 _loader_data->add_to_deallocate_list(_cp);
1426 if (_scratch_cp != NULL) {
1427 _loader_data->add_to_deallocate_list(_scratch_cp);
1428 }
1429 }
1430 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; }
1431 };
1432
1433 // Merge constant pools between the_class and scratch_class and
1434 // potentially rewrite bytecodes in scratch_class to use the merged
1435 // constant pool.
1436 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite(
1437 instanceKlassHandle the_class, instanceKlassHandle scratch_class,
1438 TRAPS) {
1439 // worst case merged constant pool length is old and new combined
1440 int merge_cp_length = the_class->constants()->length()
1441 + scratch_class->constants()->length();
1442
1443 // Constant pools are not easily reused so we allocate a new one
1444 // each time.
1445 // merge_cp is created unsafe for concurrent GC processing. It
1446 // should be marked safe before discarding it. Even though
1447 // garbage, if it crosses a card boundary, it may be scanned
1448 // in order to find the start of the first complete object on the card.
1449 ClassLoaderData* loader_data = the_class->class_loader_data();
1450 ConstantPool* merge_cp_oop =
1451 ConstantPool::allocate(loader_data,
1452 merge_cp_length,
1453 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1454 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop);
1455
1456 HandleMark hm(THREAD); // make sure handles are cleared before
1457 // MergeCPCleaner clears out merge_cp_oop
1458 constantPoolHandle merge_cp(THREAD, merge_cp_oop);
1459
1460 // Get constants() from the old class because it could have been rewritten
1461 // while we were at a safepoint allocating a new constant pool.
1462 constantPoolHandle old_cp(THREAD, the_class->constants());
1463 constantPoolHandle scratch_cp(THREAD, scratch_class->constants());
1464
1465 // If the length changed, the class was redefined out from under us. Return
1466 // an error.
1467 if (merge_cp_length != the_class->constants()->length()
1468 + scratch_class->constants()->length()) {
1469 return JVMTI_ERROR_INTERNAL;
1470 }
1471
1472 // Update the version number of the constant pools (may keep scratch_cp)
1473 merge_cp->increment_and_save_version(old_cp->version());
1474 scratch_cp->increment_and_save_version(old_cp->version());
1475
1476 ResourceMark rm(THREAD);
1477 _index_map_count = 0;
1478 _index_map_p = new intArray(scratch_cp->length(), scratch_cp->length(), -1);
1479
1480 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands());
1481 _operands_index_map_count = 0;
1482 int operands_index_map_len = ConstantPool::operand_array_length(scratch_cp->operands());
1483 _operands_index_map_p = new intArray(operands_index_map_len, operands_index_map_len, -1);
1484
1485 // reference to the cp holder is needed for copy_operands()
1486 merge_cp->set_pool_holder(scratch_class());
1487 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp,
1488 &merge_cp_length, THREAD);
1489 merge_cp->set_pool_holder(NULL);
1490
1491 if (!result) {
1492 // The merge can fail due to memory allocation failure or due
1493 // to robustness checks.
1494 return JVMTI_ERROR_INTERNAL;
1495 }
1496
1497 log_info(redefine, class, constantpool)("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count);
1498
1499 if (_index_map_count == 0) {
1500 // there is nothing to map between the new and merged constant pools
1501
1502 if (old_cp->length() == scratch_cp->length()) {
1503 // The old and new constant pools are the same length and the
1504 // index map is empty. This means that the three constant pools
1505 // are equivalent (but not the same). Unfortunately, the new
1506 // constant pool has not gone through link resolution nor have
1507 // the new class bytecodes gone through constant pool cache
1508 // rewriting so we can't use the old constant pool with the new
1509 // class.
1510
1511 // toss the merged constant pool at return
1512 } else if (old_cp->length() < scratch_cp->length()) {
1513 // The old constant pool has fewer entries than the new constant
1514 // pool and the index map is empty. This means the new constant
1515 // pool is a superset of the old constant pool. However, the old
1516 // class bytecodes have already gone through constant pool cache
1517 // rewriting so we can't use the new constant pool with the old
1518 // class.
1519
1520 // toss the merged constant pool at return
1521 } else {
1522 // The old constant pool has more entries than the new constant
1523 // pool and the index map is empty. This means that both the old
1524 // and merged constant pools are supersets of the new constant
1525 // pool.
1526
1527 // Replace the new constant pool with a shrunken copy of the
1528 // merged constant pool
1529 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1530 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1531 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1532 // It can't be cleaned up while there are handles to it.
1533 cp_cleaner.add_scratch_cp(scratch_cp());
1534 }
1535 } else {
1536 if (log_is_enabled(Trace, redefine, class, constantpool)) {
1537 // don't want to loop unless we are tracing
1538 int count = 0;
1539 for (int i = 1; i < _index_map_p->length(); i++) {
1540 int value = _index_map_p->at(i);
1541
1542 if (value != -1) {
1543 log_trace(redefine, class, constantpool)("index_map[%d]: old=%d new=%d", count, i, value);
1544 count++;
1545 }
1546 }
1547 }
1548
1549 // We have entries mapped between the new and merged constant pools
1550 // so we have to rewrite some constant pool references.
1551 if (!rewrite_cp_refs(scratch_class, THREAD)) {
1552 return JVMTI_ERROR_INTERNAL;
1553 }
1554
1555 // Replace the new constant pool with a shrunken copy of the
1556 // merged constant pool so now the rewritten bytecodes have
1557 // valid references; the previous new constant pool will get
1558 // GCed.
1559 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1560 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1561 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1562 // It can't be cleaned up while there are handles to it.
1563 cp_cleaner.add_scratch_cp(scratch_cp());
1564 }
1565
1566 return JVMTI_ERROR_NONE;
1567 } // end merge_cp_and_rewrite()
1568
1569
1570 // Rewrite constant pool references in klass scratch_class.
1571 bool VM_RedefineClasses::rewrite_cp_refs(instanceKlassHandle scratch_class,
1572 TRAPS) {
1573
1574 // rewrite constant pool references in the methods:
1575 if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) {
1576 // propagate failure back to caller
1577 return false;
1578 }
1579
1580 // rewrite constant pool references in the class_annotations:
1581 if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) {
1582 // propagate failure back to caller
1583 return false;
1584 }
1585
1586 // rewrite constant pool references in the fields_annotations:
1587 if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) {
1588 // propagate failure back to caller
1589 return false;
1590 }
1591
1592 // rewrite constant pool references in the methods_annotations:
1593 if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) {
1594 // propagate failure back to caller
1595 return false;
1596 }
1597
1598 // rewrite constant pool references in the methods_parameter_annotations:
1599 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class,
1600 THREAD)) {
1601 // propagate failure back to caller
1602 return false;
1603 }
1604
1605 // rewrite constant pool references in the methods_default_annotations:
1606 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class,
1607 THREAD)) {
1608 // propagate failure back to caller
1609 return false;
1610 }
1611
1612 // rewrite constant pool references in the class_type_annotations:
1613 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class, THREAD)) {
1614 // propagate failure back to caller
1615 return false;
1616 }
1617
1618 // rewrite constant pool references in the fields_type_annotations:
1619 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class, THREAD)) {
1620 // propagate failure back to caller
1621 return false;
1622 }
1623
1624 // rewrite constant pool references in the methods_type_annotations:
1625 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class, THREAD)) {
1626 // propagate failure back to caller
1627 return false;
1628 }
1629
1630 // There can be type annotations in the Code part of a method_info attribute.
1631 // These annotations are not accessible, even by reflection.
1632 // Currently they are not even parsed by the ClassFileParser.
1633 // If runtime access is added they will also need to be rewritten.
1634
1635 // rewrite source file name index:
1636 u2 source_file_name_idx = scratch_class->source_file_name_index();
1637 if (source_file_name_idx != 0) {
1638 u2 new_source_file_name_idx = find_new_index(source_file_name_idx);
1639 if (new_source_file_name_idx != 0) {
1640 scratch_class->set_source_file_name_index(new_source_file_name_idx);
1641 }
1642 }
1643
1644 // rewrite class generic signature index:
1645 u2 generic_signature_index = scratch_class->generic_signature_index();
1646 if (generic_signature_index != 0) {
1647 u2 new_generic_signature_index = find_new_index(generic_signature_index);
1648 if (new_generic_signature_index != 0) {
1649 scratch_class->set_generic_signature_index(new_generic_signature_index);
1650 }
1651 }
1652
1653 return true;
1654 } // end rewrite_cp_refs()
1655
1656 // Rewrite constant pool references in the methods.
1657 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(
1658 instanceKlassHandle scratch_class, TRAPS) {
1659
1660 Array<Method*>* methods = scratch_class->methods();
1661
1662 if (methods == NULL || methods->length() == 0) {
1663 // no methods so nothing to do
1664 return true;
1665 }
1666
1667 // rewrite constant pool references in the methods:
1668 for (int i = methods->length() - 1; i >= 0; i--) {
1669 methodHandle method(THREAD, methods->at(i));
1670 methodHandle new_method;
1671 rewrite_cp_refs_in_method(method, &new_method, THREAD);
1672 if (!new_method.is_null()) {
1673 // the method has been replaced so save the new method version
1674 // even in the case of an exception. original method is on the
1675 // deallocation list.
1676 methods->at_put(i, new_method());
1677 }
1678 if (HAS_PENDING_EXCEPTION) {
1679 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1680 log_info(redefine, class, load, exceptions)("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string());
1681 // Need to clear pending exception here as the super caller sets
1682 // the JVMTI_ERROR_INTERNAL if the returned value is false.
1683 CLEAR_PENDING_EXCEPTION;
1684 return false;
1685 }
1686 }
1687
1688 return true;
1689 }
1690
1691
1692 // Rewrite constant pool references in the specific method. This code
1693 // was adapted from Rewriter::rewrite_method().
1694 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method,
1695 methodHandle *new_method_p, TRAPS) {
1696
1697 *new_method_p = methodHandle(); // default is no new method
1698
1699 // We cache a pointer to the bytecodes here in code_base. If GC
1700 // moves the Method*, then the bytecodes will also move which
1701 // will likely cause a crash. We create a NoSafepointVerifier
1702 // object to detect whether we pass a possible safepoint in this
1703 // code block.
1704 NoSafepointVerifier nsv;
1705
1706 // Bytecodes and their length
1707 address code_base = method->code_base();
1708 int code_length = method->code_size();
1709
1710 int bc_length;
1711 for (int bci = 0; bci < code_length; bci += bc_length) {
1712 address bcp = code_base + bci;
1713 Bytecodes::Code c = (Bytecodes::Code)(*bcp);
1714
1715 bc_length = Bytecodes::length_for(c);
1716 if (bc_length == 0) {
1717 // More complicated bytecodes report a length of zero so
1718 // we have to try again a slightly different way.
1719 bc_length = Bytecodes::length_at(method(), bcp);
1720 }
1721
1722 assert(bc_length != 0, "impossible bytecode length");
1723
1724 switch (c) {
1725 case Bytecodes::_ldc:
1726 {
1727 int cp_index = *(bcp + 1);
1728 int new_index = find_new_index(cp_index);
1729
1730 if (StressLdcRewrite && new_index == 0) {
1731 // If we are stressing ldc -> ldc_w rewriting, then we
1732 // always need a new_index value.
1733 new_index = cp_index;
1734 }
1735 if (new_index != 0) {
1736 // the original index is mapped so we have more work to do
1737 if (!StressLdcRewrite && new_index <= max_jubyte) {
1738 // The new value can still use ldc instead of ldc_w
1739 // unless we are trying to stress ldc -> ldc_w rewriting
1740 log_trace(redefine, class, constantpool)
1741 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index);
1742 *(bcp + 1) = new_index;
1743 } else {
1744 log_trace(redefine, class, constantpool)
1745 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index);
1746 // the new value needs ldc_w instead of ldc
1747 u_char inst_buffer[4]; // max instruction size is 4 bytes
1748 bcp = (address)inst_buffer;
1749 // construct new instruction sequence
1750 *bcp = Bytecodes::_ldc_w;
1751 bcp++;
1752 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w.
1753 // See comment below for difference between put_Java_u2()
1754 // and put_native_u2().
1755 Bytes::put_Java_u2(bcp, new_index);
1756
1757 Relocator rc(method, NULL /* no RelocatorListener needed */);
1758 methodHandle m;
1759 {
1760 PauseNoSafepointVerifier pnsv(&nsv);
1761
1762 // ldc is 2 bytes and ldc_w is 3 bytes
1763 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK);
1764 }
1765
1766 // return the new method so that the caller can update
1767 // the containing class
1768 *new_method_p = method = m;
1769 // switch our bytecode processing loop from the old method
1770 // to the new method
1771 code_base = method->code_base();
1772 code_length = method->code_size();
1773 bcp = code_base + bci;
1774 c = (Bytecodes::Code)(*bcp);
1775 bc_length = Bytecodes::length_for(c);
1776 assert(bc_length != 0, "sanity check");
1777 } // end we need ldc_w instead of ldc
1778 } // end if there is a mapped index
1779 } break;
1780
1781 // these bytecodes have a two-byte constant pool index
1782 case Bytecodes::_anewarray : // fall through
1783 case Bytecodes::_checkcast : // fall through
1784 case Bytecodes::_getfield : // fall through
1785 case Bytecodes::_getstatic : // fall through
1786 case Bytecodes::_instanceof : // fall through
1787 case Bytecodes::_invokedynamic : // fall through
1788 case Bytecodes::_invokeinterface: // fall through
1789 case Bytecodes::_invokespecial : // fall through
1790 case Bytecodes::_invokestatic : // fall through
1791 case Bytecodes::_invokevirtual : // fall through
1792 case Bytecodes::_ldc_w : // fall through
1793 case Bytecodes::_ldc2_w : // fall through
1794 case Bytecodes::_multianewarray : // fall through
1795 case Bytecodes::_new : // fall through
1796 case Bytecodes::_putfield : // fall through
1797 case Bytecodes::_putstatic :
1798 {
1799 address p = bcp + 1;
1800 int cp_index = Bytes::get_Java_u2(p);
1801 int new_index = find_new_index(cp_index);
1802 if (new_index != 0) {
1803 // the original index is mapped so update w/ new value
1804 log_trace(redefine, class, constantpool)
1805 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),p2i(bcp), cp_index, new_index);
1806 // Rewriter::rewrite_method() uses put_native_u2() in this
1807 // situation because it is reusing the constant pool index
1808 // location for a native index into the ConstantPoolCache.
1809 // Since we are updating the constant pool index prior to
1810 // verification and ConstantPoolCache initialization, we
1811 // need to keep the new index in Java byte order.
1812 Bytes::put_Java_u2(p, new_index);
1813 }
1814 } break;
1815 }
1816 } // end for each bytecode
1817
1818 // We also need to rewrite the parameter name indexes, if there is
1819 // method parameter data present
1820 if(method->has_method_parameters()) {
1821 const int len = method->method_parameters_length();
1822 MethodParametersElement* elem = method->method_parameters_start();
1823
1824 for (int i = 0; i < len; i++) {
1825 const u2 cp_index = elem[i].name_cp_index;
1826 const u2 new_cp_index = find_new_index(cp_index);
1827 if (new_cp_index != 0) {
1828 elem[i].name_cp_index = new_cp_index;
1829 }
1830 }
1831 }
1832 } // end rewrite_cp_refs_in_method()
1833
1834
1835 // Rewrite constant pool references in the class_annotations field.
1836 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(
1837 instanceKlassHandle scratch_class, TRAPS) {
1838
1839 AnnotationArray* class_annotations = scratch_class->class_annotations();
1840 if (class_annotations == NULL || class_annotations->length() == 0) {
1841 // no class_annotations so nothing to do
1842 return true;
1843 }
1844
1845 log_debug(redefine, class, annotation)("class_annotations length=%d", class_annotations->length());
1846
1847 int byte_i = 0; // byte index into class_annotations
1848 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i,
1849 THREAD);
1850 }
1851
1852
1853 // Rewrite constant pool references in an annotations typeArray. This
1854 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute
1855 // that is described in section 4.8.15 of the 2nd-edition of the VM spec:
1856 //
1857 // annotations_typeArray {
1858 // u2 num_annotations;
1859 // annotation annotations[num_annotations];
1860 // }
1861 //
1862 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray(
1863 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1864
1865 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1866 // not enough room for num_annotations field
1867 log_debug(redefine, class, annotation)("length() is too small for num_annotations field");
1868 return false;
1869 }
1870
1871 u2 num_annotations = Bytes::get_Java_u2((address)
1872 annotations_typeArray->adr_at(byte_i_ref));
1873 byte_i_ref += 2;
1874
1875 log_debug(redefine, class, annotation)("num_annotations=%d", num_annotations);
1876
1877 int calc_num_annotations = 0;
1878 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
1879 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
1880 byte_i_ref, THREAD)) {
1881 log_debug(redefine, class, annotation)("bad annotation_struct at %d", calc_num_annotations);
1882 // propagate failure back to caller
1883 return false;
1884 }
1885 }
1886 assert(num_annotations == calc_num_annotations, "sanity check");
1887
1888 return true;
1889 } // end rewrite_cp_refs_in_annotations_typeArray()
1890
1891
1892 // Rewrite constant pool references in the annotation struct portion of
1893 // an annotations_typeArray. This "structure" is from section 4.8.15 of
1894 // the 2nd-edition of the VM spec:
1895 //
1896 // struct annotation {
1897 // u2 type_index;
1898 // u2 num_element_value_pairs;
1899 // {
1900 // u2 element_name_index;
1901 // element_value value;
1902 // } element_value_pairs[num_element_value_pairs];
1903 // }
1904 //
1905 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct(
1906 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1907 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) {
1908 // not enough room for smallest annotation_struct
1909 log_debug(redefine, class, annotation)("length() is too small for annotation_struct");
1910 return false;
1911 }
1912
1913 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray,
1914 byte_i_ref, "type_index", THREAD);
1915
1916 u2 num_element_value_pairs = Bytes::get_Java_u2((address)
1917 annotations_typeArray->adr_at(byte_i_ref));
1918 byte_i_ref += 2;
1919
1920 log_debug(redefine, class, annotation)
1921 ("type_index=%d num_element_value_pairs=%d", type_index, num_element_value_pairs);
1922
1923 int calc_num_element_value_pairs = 0;
1924 for (; calc_num_element_value_pairs < num_element_value_pairs;
1925 calc_num_element_value_pairs++) {
1926 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1927 // not enough room for another element_name_index, let alone
1928 // the rest of another component
1929 log_debug(redefine, class, annotation)("length() is too small for element_name_index");
1930 return false;
1931 }
1932
1933 u2 element_name_index = rewrite_cp_ref_in_annotation_data(
1934 annotations_typeArray, byte_i_ref,
1935 "element_name_index", THREAD);
1936
1937 log_debug(redefine, class, annotation)("element_name_index=%d", element_name_index);
1938
1939 if (!rewrite_cp_refs_in_element_value(annotations_typeArray,
1940 byte_i_ref, THREAD)) {
1941 log_debug(redefine, class, annotation)("bad element_value at %d", calc_num_element_value_pairs);
1942 // propagate failure back to caller
1943 return false;
1944 }
1945 } // end for each component
1946 assert(num_element_value_pairs == calc_num_element_value_pairs,
1947 "sanity check");
1948
1949 return true;
1950 } // end rewrite_cp_refs_in_annotation_struct()
1951
1952
1953 // Rewrite a constant pool reference at the current position in
1954 // annotations_typeArray if needed. Returns the original constant
1955 // pool reference if a rewrite was not needed or the new constant
1956 // pool reference if a rewrite was needed.
1957 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data(
1958 AnnotationArray* annotations_typeArray, int &byte_i_ref,
1959 const char * trace_mesg, TRAPS) {
1960
1961 address cp_index_addr = (address)
1962 annotations_typeArray->adr_at(byte_i_ref);
1963 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr);
1964 u2 new_cp_index = find_new_index(old_cp_index);
1965 if (new_cp_index != 0) {
1966 log_debug(redefine, class, annotation)("mapped old %s=%d", trace_mesg, old_cp_index);
1967 Bytes::put_Java_u2(cp_index_addr, new_cp_index);
1968 old_cp_index = new_cp_index;
1969 }
1970 byte_i_ref += 2;
1971 return old_cp_index;
1972 }
1973
1974
1975 // Rewrite constant pool references in the element_value portion of an
1976 // annotations_typeArray. This "structure" is from section 4.8.15.1 of
1977 // the 2nd-edition of the VM spec:
1978 //
1979 // struct element_value {
1980 // u1 tag;
1981 // union {
1982 // u2 const_value_index;
1983 // {
1984 // u2 type_name_index;
1985 // u2 const_name_index;
1986 // } enum_const_value;
1987 // u2 class_info_index;
1988 // annotation annotation_value;
1989 // struct {
1990 // u2 num_values;
1991 // element_value values[num_values];
1992 // } array_value;
1993 // } value;
1994 // }
1995 //
1996 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value(
1997 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1998
1999 if ((byte_i_ref + 1) > annotations_typeArray->length()) {
2000 // not enough room for a tag let alone the rest of an element_value
2001 log_debug(redefine, class, annotation)("length() is too small for a tag");
2002 return false;
2003 }
2004
2005 u1 tag = annotations_typeArray->at(byte_i_ref);
2006 byte_i_ref++;
2007 log_debug(redefine, class, annotation)("tag='%c'", tag);
2008
2009 switch (tag) {
2010 // These BaseType tag values are from Table 4.2 in VM spec:
2011 case 'B': // byte
2012 case 'C': // char
2013 case 'D': // double
2014 case 'F': // float
2015 case 'I': // int
2016 case 'J': // long
2017 case 'S': // short
2018 case 'Z': // boolean
2019
2020 // The remaining tag values are from Table 4.8 in the 2nd-edition of
2021 // the VM spec:
2022 case 's':
2023 {
2024 // For the above tag values (including the BaseType values),
2025 // value.const_value_index is right union field.
2026
2027 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2028 // not enough room for a const_value_index
2029 log_debug(redefine, class, annotation)("length() is too small for a const_value_index");
2030 return false;
2031 }
2032
2033 u2 const_value_index = rewrite_cp_ref_in_annotation_data(
2034 annotations_typeArray, byte_i_ref,
2035 "const_value_index", THREAD);
2036
2037 log_debug(redefine, class, annotation)("const_value_index=%d", const_value_index);
2038 } break;
2039
2040 case 'e':
2041 {
2042 // for the above tag value, value.enum_const_value is right union field
2043
2044 if ((byte_i_ref + 4) > annotations_typeArray->length()) {
2045 // not enough room for a enum_const_value
2046 log_debug(redefine, class, annotation)("length() is too small for a enum_const_value");
2047 return false;
2048 }
2049
2050 u2 type_name_index = rewrite_cp_ref_in_annotation_data(
2051 annotations_typeArray, byte_i_ref,
2052 "type_name_index", THREAD);
2053
2054 u2 const_name_index = rewrite_cp_ref_in_annotation_data(
2055 annotations_typeArray, byte_i_ref,
2056 "const_name_index", THREAD);
2057
2058 log_debug(redefine, class, annotation)
2059 ("type_name_index=%d const_name_index=%d", type_name_index, const_name_index);
2060 } break;
2061
2062 case 'c':
2063 {
2064 // for the above tag value, value.class_info_index is right union field
2065
2066 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2067 // not enough room for a class_info_index
2068 log_debug(redefine, class, annotation)("length() is too small for a class_info_index");
2069 return false;
2070 }
2071
2072 u2 class_info_index = rewrite_cp_ref_in_annotation_data(
2073 annotations_typeArray, byte_i_ref,
2074 "class_info_index", THREAD);
2075
2076 log_debug(redefine, class, annotation)("class_info_index=%d", class_info_index);
2077 } break;
2078
2079 case '@':
2080 // For the above tag value, value.attr_value is the right union
2081 // field. This is a nested annotation.
2082 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
2083 byte_i_ref, THREAD)) {
2084 // propagate failure back to caller
2085 return false;
2086 }
2087 break;
2088
2089 case '[':
2090 {
2091 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2092 // not enough room for a num_values field
2093 log_debug(redefine, class, annotation)("length() is too small for a num_values field");
2094 return false;
2095 }
2096
2097 // For the above tag value, value.array_value is the right union
2098 // field. This is an array of nested element_value.
2099 u2 num_values = Bytes::get_Java_u2((address)
2100 annotations_typeArray->adr_at(byte_i_ref));
2101 byte_i_ref += 2;
2102 log_debug(redefine, class, annotation)("num_values=%d", num_values);
2103
2104 int calc_num_values = 0;
2105 for (; calc_num_values < num_values; calc_num_values++) {
2106 if (!rewrite_cp_refs_in_element_value(
2107 annotations_typeArray, byte_i_ref, THREAD)) {
2108 log_debug(redefine, class, annotation)("bad nested element_value at %d", calc_num_values);
2109 // propagate failure back to caller
2110 return false;
2111 }
2112 }
2113 assert(num_values == calc_num_values, "sanity check");
2114 } break;
2115
2116 default:
2117 log_debug(redefine, class, annotation)("bad tag=0x%x", tag);
2118 return false;
2119 } // end decode tag field
2120
2121 return true;
2122 } // end rewrite_cp_refs_in_element_value()
2123
2124
2125 // Rewrite constant pool references in a fields_annotations field.
2126 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations(
2127 instanceKlassHandle scratch_class, TRAPS) {
2128
2129 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations();
2130
2131 if (fields_annotations == NULL || fields_annotations->length() == 0) {
2132 // no fields_annotations so nothing to do
2133 return true;
2134 }
2135
2136 log_debug(redefine, class, annotation)("fields_annotations length=%d", fields_annotations->length());
2137
2138 for (int i = 0; i < fields_annotations->length(); i++) {
2139 AnnotationArray* field_annotations = fields_annotations->at(i);
2140 if (field_annotations == NULL || field_annotations->length() == 0) {
2141 // this field does not have any annotations so skip it
2142 continue;
2143 }
2144
2145 int byte_i = 0; // byte index into field_annotations
2146 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i,
2147 THREAD)) {
2148 log_debug(redefine, class, annotation)("bad field_annotations at %d", i);
2149 // propagate failure back to caller
2150 return false;
2151 }
2152 }
2153
2154 return true;
2155 } // end rewrite_cp_refs_in_fields_annotations()
2156
2157
2158 // Rewrite constant pool references in a methods_annotations field.
2159 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations(
2160 instanceKlassHandle scratch_class, TRAPS) {
2161
2162 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2163 Method* m = scratch_class->methods()->at(i);
2164 AnnotationArray* method_annotations = m->constMethod()->method_annotations();
2165
2166 if (method_annotations == NULL || method_annotations->length() == 0) {
2167 // this method does not have any annotations so skip it
2168 continue;
2169 }
2170
2171 int byte_i = 0; // byte index into method_annotations
2172 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i,
2173 THREAD)) {
2174 log_debug(redefine, class, annotation)("bad method_annotations at %d", i);
2175 // propagate failure back to caller
2176 return false;
2177 }
2178 }
2179
2180 return true;
2181 } // end rewrite_cp_refs_in_methods_annotations()
2182
2183
2184 // Rewrite constant pool references in a methods_parameter_annotations
2185 // field. This "structure" is adapted from the
2186 // RuntimeVisibleParameterAnnotations_attribute described in section
2187 // 4.8.17 of the 2nd-edition of the VM spec:
2188 //
2189 // methods_parameter_annotations_typeArray {
2190 // u1 num_parameters;
2191 // {
2192 // u2 num_annotations;
2193 // annotation annotations[num_annotations];
2194 // } parameter_annotations[num_parameters];
2195 // }
2196 //
2197 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations(
2198 instanceKlassHandle scratch_class, TRAPS) {
2199
2200 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2201 Method* m = scratch_class->methods()->at(i);
2202 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations();
2203 if (method_parameter_annotations == NULL
2204 || method_parameter_annotations->length() == 0) {
2205 // this method does not have any parameter annotations so skip it
2206 continue;
2207 }
2208
2209 if (method_parameter_annotations->length() < 1) {
2210 // not enough room for a num_parameters field
2211 log_debug(redefine, class, annotation)("length() is too small for a num_parameters field at %d", i);
2212 return false;
2213 }
2214
2215 int byte_i = 0; // byte index into method_parameter_annotations
2216
2217 u1 num_parameters = method_parameter_annotations->at(byte_i);
2218 byte_i++;
2219
2220 log_debug(redefine, class, annotation)("num_parameters=%d", num_parameters);
2221
2222 int calc_num_parameters = 0;
2223 for (; calc_num_parameters < num_parameters; calc_num_parameters++) {
2224 if (!rewrite_cp_refs_in_annotations_typeArray(
2225 method_parameter_annotations, byte_i, THREAD)) {
2226 log_debug(redefine, class, annotation)("bad method_parameter_annotations at %d", calc_num_parameters);
2227 // propagate failure back to caller
2228 return false;
2229 }
2230 }
2231 assert(num_parameters == calc_num_parameters, "sanity check");
2232 }
2233
2234 return true;
2235 } // end rewrite_cp_refs_in_methods_parameter_annotations()
2236
2237
2238 // Rewrite constant pool references in a methods_default_annotations
2239 // field. This "structure" is adapted from the AnnotationDefault_attribute
2240 // that is described in section 4.8.19 of the 2nd-edition of the VM spec:
2241 //
2242 // methods_default_annotations_typeArray {
2243 // element_value default_value;
2244 // }
2245 //
2246 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations(
2247 instanceKlassHandle scratch_class, TRAPS) {
2248
2249 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2250 Method* m = scratch_class->methods()->at(i);
2251 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations();
2252 if (method_default_annotations == NULL
2253 || method_default_annotations->length() == 0) {
2254 // this method does not have any default annotations so skip it
2255 continue;
2256 }
2257
2258 int byte_i = 0; // byte index into method_default_annotations
2259
2260 if (!rewrite_cp_refs_in_element_value(
2261 method_default_annotations, byte_i, THREAD)) {
2262 log_debug(redefine, class, annotation)("bad default element_value at %d", i);
2263 // propagate failure back to caller
2264 return false;
2265 }
2266 }
2267
2268 return true;
2269 } // end rewrite_cp_refs_in_methods_default_annotations()
2270
2271
2272 // Rewrite constant pool references in a class_type_annotations field.
2273 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations(
2274 instanceKlassHandle scratch_class, TRAPS) {
2275
2276 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations();
2277 if (class_type_annotations == NULL || class_type_annotations->length() == 0) {
2278 // no class_type_annotations so nothing to do
2279 return true;
2280 }
2281
2282 log_debug(redefine, class, annotation)("class_type_annotations length=%d", class_type_annotations->length());
2283
2284 int byte_i = 0; // byte index into class_type_annotations
2285 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations,
2286 byte_i, "ClassFile", THREAD);
2287 } // end rewrite_cp_refs_in_class_type_annotations()
2288
2289
2290 // Rewrite constant pool references in a fields_type_annotations field.
2291 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations(
2292 instanceKlassHandle scratch_class, TRAPS) {
2293
2294 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations();
2295 if (fields_type_annotations == NULL || fields_type_annotations->length() == 0) {
2296 // no fields_type_annotations so nothing to do
2297 return true;
2298 }
2299
2300 log_debug(redefine, class, annotation)("fields_type_annotations length=%d", fields_type_annotations->length());
2301
2302 for (int i = 0; i < fields_type_annotations->length(); i++) {
2303 AnnotationArray* field_type_annotations = fields_type_annotations->at(i);
2304 if (field_type_annotations == NULL || field_type_annotations->length() == 0) {
2305 // this field does not have any annotations so skip it
2306 continue;
2307 }
2308
2309 int byte_i = 0; // byte index into field_type_annotations
2310 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations,
2311 byte_i, "field_info", THREAD)) {
2312 log_debug(redefine, class, annotation)("bad field_type_annotations at %d", i);
2313 // propagate failure back to caller
2314 return false;
2315 }
2316 }
2317
2318 return true;
2319 } // end rewrite_cp_refs_in_fields_type_annotations()
2320
2321
2322 // Rewrite constant pool references in a methods_type_annotations field.
2323 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations(
2324 instanceKlassHandle scratch_class, TRAPS) {
2325
2326 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2327 Method* m = scratch_class->methods()->at(i);
2328 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations();
2329
2330 if (method_type_annotations == NULL || method_type_annotations->length() == 0) {
2331 // this method does not have any annotations so skip it
2332 continue;
2333 }
2334
2335 log_debug(redefine, class, annotation)("methods type_annotations length=%d", method_type_annotations->length());
2336
2337 int byte_i = 0; // byte index into method_type_annotations
2338 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations,
2339 byte_i, "method_info", THREAD)) {
2340 log_debug(redefine, class, annotation)("bad method_type_annotations at %d", i);
2341 // propagate failure back to caller
2342 return false;
2343 }
2344 }
2345
2346 return true;
2347 } // end rewrite_cp_refs_in_methods_type_annotations()
2348
2349
2350 // Rewrite constant pool references in a type_annotations
2351 // field. This "structure" is adapted from the
2352 // RuntimeVisibleTypeAnnotations_attribute described in
2353 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2354 //
2355 // type_annotations_typeArray {
2356 // u2 num_annotations;
2357 // type_annotation annotations[num_annotations];
2358 // }
2359 //
2360 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray(
2361 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2362 const char * location_mesg, TRAPS) {
2363
2364 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2365 // not enough room for num_annotations field
2366 log_debug(redefine, class, annotation)("length() is too small for num_annotations field");
2367 return false;
2368 }
2369
2370 u2 num_annotations = Bytes::get_Java_u2((address)
2371 type_annotations_typeArray->adr_at(byte_i_ref));
2372 byte_i_ref += 2;
2373
2374 log_debug(redefine, class, annotation)("num_type_annotations=%d", num_annotations);
2375
2376 int calc_num_annotations = 0;
2377 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
2378 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray,
2379 byte_i_ref, location_mesg, THREAD)) {
2380 log_debug(redefine, class, annotation)("bad type_annotation_struct at %d", calc_num_annotations);
2381 // propagate failure back to caller
2382 return false;
2383 }
2384 }
2385 assert(num_annotations == calc_num_annotations, "sanity check");
2386
2387 if (byte_i_ref != type_annotations_typeArray->length()) {
2388 log_debug(redefine, class, annotation)
2389 ("read wrong amount of bytes at end of processing type_annotations_typeArray (%d of %d bytes were read)",
2390 byte_i_ref, type_annotations_typeArray->length());
2391 return false;
2392 }
2393
2394 return true;
2395 } // end rewrite_cp_refs_in_type_annotations_typeArray()
2396
2397
2398 // Rewrite constant pool references in a type_annotation
2399 // field. This "structure" is adapted from the
2400 // RuntimeVisibleTypeAnnotations_attribute described in
2401 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2402 //
2403 // type_annotation {
2404 // u1 target_type;
2405 // union {
2406 // type_parameter_target;
2407 // supertype_target;
2408 // type_parameter_bound_target;
2409 // empty_target;
2410 // method_formal_parameter_target;
2411 // throws_target;
2412 // localvar_target;
2413 // catch_target;
2414 // offset_target;
2415 // type_argument_target;
2416 // } target_info;
2417 // type_path target_path;
2418 // annotation anno;
2419 // }
2420 //
2421 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct(
2422 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2423 const char * location_mesg, TRAPS) {
2424
2425 if (!skip_type_annotation_target(type_annotations_typeArray,
2426 byte_i_ref, location_mesg, THREAD)) {
2427 return false;
2428 }
2429
2430 if (!skip_type_annotation_type_path(type_annotations_typeArray,
2431 byte_i_ref, THREAD)) {
2432 return false;
2433 }
2434
2435 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray,
2436 byte_i_ref, THREAD)) {
2437 return false;
2438 }
2439
2440 return true;
2441 } // end rewrite_cp_refs_in_type_annotation_struct()
2442
2443
2444 // Read, verify and skip over the target_type and target_info part
2445 // so that rewriting can continue in the later parts of the struct.
2446 //
2447 // u1 target_type;
2448 // union {
2449 // type_parameter_target;
2450 // supertype_target;
2451 // type_parameter_bound_target;
2452 // empty_target;
2453 // method_formal_parameter_target;
2454 // throws_target;
2455 // localvar_target;
2456 // catch_target;
2457 // offset_target;
2458 // type_argument_target;
2459 // } target_info;
2460 //
2461 bool VM_RedefineClasses::skip_type_annotation_target(
2462 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2463 const char * location_mesg, TRAPS) {
2464
2465 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2466 // not enough room for a target_type let alone the rest of a type_annotation
2467 log_debug(redefine, class, annotation)("length() is too small for a target_type");
2468 return false;
2469 }
2470
2471 u1 target_type = type_annotations_typeArray->at(byte_i_ref);
2472 byte_i_ref += 1;
2473 log_debug(redefine, class, annotation)("target_type=0x%.2x", target_type);
2474 log_debug(redefine, class, annotation)("location=%s", location_mesg);
2475
2476 // Skip over target_info
2477 switch (target_type) {
2478 case 0x00:
2479 // kind: type parameter declaration of generic class or interface
2480 // location: ClassFile
2481 case 0x01:
2482 // kind: type parameter declaration of generic method or constructor
2483 // location: method_info
2484
2485 {
2486 // struct:
2487 // type_parameter_target {
2488 // u1 type_parameter_index;
2489 // }
2490 //
2491 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2492 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_target");
2493 return false;
2494 }
2495
2496 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2497 byte_i_ref += 1;
2498
2499 log_debug(redefine, class, annotation)("type_parameter_target: type_parameter_index=%d", type_parameter_index);
2500 } break;
2501
2502 case 0x10:
2503 // kind: type in extends clause of class or interface declaration
2504 // (including the direct superclass of an anonymous class declaration),
2505 // or in implements clause of interface declaration
2506 // location: ClassFile
2507
2508 {
2509 // struct:
2510 // supertype_target {
2511 // u2 supertype_index;
2512 // }
2513 //
2514 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2515 log_debug(redefine, class, annotation)("length() is too small for a supertype_target");
2516 return false;
2517 }
2518
2519 u2 supertype_index = Bytes::get_Java_u2((address)
2520 type_annotations_typeArray->adr_at(byte_i_ref));
2521 byte_i_ref += 2;
2522
2523 log_debug(redefine, class, annotation)("supertype_target: supertype_index=%d", supertype_index);
2524 } break;
2525
2526 case 0x11:
2527 // kind: type in bound of type parameter declaration of generic class or interface
2528 // location: ClassFile
2529 case 0x12:
2530 // kind: type in bound of type parameter declaration of generic method or constructor
2531 // location: method_info
2532
2533 {
2534 // struct:
2535 // type_parameter_bound_target {
2536 // u1 type_parameter_index;
2537 // u1 bound_index;
2538 // }
2539 //
2540 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2541 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_bound_target");
2542 return false;
2543 }
2544
2545 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2546 byte_i_ref += 1;
2547 u1 bound_index = type_annotations_typeArray->at(byte_i_ref);
2548 byte_i_ref += 1;
2549
2550 log_debug(redefine, class, annotation)
2551 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d", type_parameter_index, bound_index);
2552 } break;
2553
2554 case 0x13:
2555 // kind: type in field declaration
2556 // location: field_info
2557 case 0x14:
2558 // kind: return type of method, or type of newly constructed object
2559 // location: method_info
2560 case 0x15:
2561 // kind: receiver type of method or constructor
2562 // location: method_info
2563
2564 {
2565 // struct:
2566 // empty_target {
2567 // }
2568 //
2569 log_debug(redefine, class, annotation)("empty_target");
2570 } break;
2571
2572 case 0x16:
2573 // kind: type in formal parameter declaration of method, constructor, or lambda expression
2574 // location: method_info
2575
2576 {
2577 // struct:
2578 // formal_parameter_target {
2579 // u1 formal_parameter_index;
2580 // }
2581 //
2582 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2583 log_debug(redefine, class, annotation)("length() is too small for a formal_parameter_target");
2584 return false;
2585 }
2586
2587 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2588 byte_i_ref += 1;
2589
2590 log_debug(redefine, class, annotation)
2591 ("formal_parameter_target: formal_parameter_index=%d", formal_parameter_index);
2592 } break;
2593
2594 case 0x17:
2595 // kind: type in throws clause of method or constructor
2596 // location: method_info
2597
2598 {
2599 // struct:
2600 // throws_target {
2601 // u2 throws_type_index
2602 // }
2603 //
2604 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2605 log_debug(redefine, class, annotation)("length() is too small for a throws_target");
2606 return false;
2607 }
2608
2609 u2 throws_type_index = Bytes::get_Java_u2((address)
2610 type_annotations_typeArray->adr_at(byte_i_ref));
2611 byte_i_ref += 2;
2612
2613 log_debug(redefine, class, annotation)("throws_target: throws_type_index=%d", throws_type_index);
2614 } break;
2615
2616 case 0x40:
2617 // kind: type in local variable declaration
2618 // location: Code
2619 case 0x41:
2620 // kind: type in resource variable declaration
2621 // location: Code
2622
2623 {
2624 // struct:
2625 // localvar_target {
2626 // u2 table_length;
2627 // struct {
2628 // u2 start_pc;
2629 // u2 length;
2630 // u2 index;
2631 // } table[table_length];
2632 // }
2633 //
2634 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2635 // not enough room for a table_length let alone the rest of a localvar_target
2636 log_debug(redefine, class, annotation)("length() is too small for a localvar_target table_length");
2637 return false;
2638 }
2639
2640 u2 table_length = Bytes::get_Java_u2((address)
2641 type_annotations_typeArray->adr_at(byte_i_ref));
2642 byte_i_ref += 2;
2643
2644 log_debug(redefine, class, annotation)("localvar_target: table_length=%d", table_length);
2645
2646 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry
2647 int table_size = table_length * table_struct_size;
2648
2649 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) {
2650 // not enough room for a table
2651 log_debug(redefine, class, annotation)("length() is too small for a table array of length %d", table_length);
2652 return false;
2653 }
2654
2655 // Skip over table
2656 byte_i_ref += table_size;
2657 } break;
2658
2659 case 0x42:
2660 // kind: type in exception parameter declaration
2661 // location: Code
2662
2663 {
2664 // struct:
2665 // catch_target {
2666 // u2 exception_table_index;
2667 // }
2668 //
2669 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2670 log_debug(redefine, class, annotation)("length() is too small for a catch_target");
2671 return false;
2672 }
2673
2674 u2 exception_table_index = Bytes::get_Java_u2((address)
2675 type_annotations_typeArray->adr_at(byte_i_ref));
2676 byte_i_ref += 2;
2677
2678 log_debug(redefine, class, annotation)("catch_target: exception_table_index=%d", exception_table_index);
2679 } break;
2680
2681 case 0x43:
2682 // kind: type in instanceof expression
2683 // location: Code
2684 case 0x44:
2685 // kind: type in new expression
2686 // location: Code
2687 case 0x45:
2688 // kind: type in method reference expression using ::new
2689 // location: Code
2690 case 0x46:
2691 // kind: type in method reference expression using ::Identifier
2692 // location: Code
2693
2694 {
2695 // struct:
2696 // offset_target {
2697 // u2 offset;
2698 // }
2699 //
2700 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2701 log_debug(redefine, class, annotation)("length() is too small for a offset_target");
2702 return false;
2703 }
2704
2705 u2 offset = Bytes::get_Java_u2((address)
2706 type_annotations_typeArray->adr_at(byte_i_ref));
2707 byte_i_ref += 2;
2708
2709 log_debug(redefine, class, annotation)("offset_target: offset=%d", offset);
2710 } break;
2711
2712 case 0x47:
2713 // kind: type in cast expression
2714 // location: Code
2715 case 0x48:
2716 // kind: type argument for generic constructor in new expression or
2717 // explicit constructor invocation statement
2718 // location: Code
2719 case 0x49:
2720 // kind: type argument for generic method in method invocation expression
2721 // location: Code
2722 case 0x4A:
2723 // kind: type argument for generic constructor in method reference expression using ::new
2724 // location: Code
2725 case 0x4B:
2726 // kind: type argument for generic method in method reference expression using ::Identifier
2727 // location: Code
2728
2729 {
2730 // struct:
2731 // type_argument_target {
2732 // u2 offset;
2733 // u1 type_argument_index;
2734 // }
2735 //
2736 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) {
2737 log_debug(redefine, class, annotation)("length() is too small for a type_argument_target");
2738 return false;
2739 }
2740
2741 u2 offset = Bytes::get_Java_u2((address)
2742 type_annotations_typeArray->adr_at(byte_i_ref));
2743 byte_i_ref += 2;
2744 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
2745 byte_i_ref += 1;
2746
2747 log_debug(redefine, class, annotation)
2748 ("type_argument_target: offset=%d, type_argument_index=%d", offset, type_argument_index);
2749 } break;
2750
2751 default:
2752 log_debug(redefine, class, annotation)("unknown target_type");
2753 #ifdef ASSERT
2754 ShouldNotReachHere();
2755 #endif
2756 return false;
2757 }
2758
2759 return true;
2760 } // end skip_type_annotation_target()
2761
2762
2763 // Read, verify and skip over the type_path part so that rewriting
2764 // can continue in the later parts of the struct.
2765 //
2766 // type_path {
2767 // u1 path_length;
2768 // {
2769 // u1 type_path_kind;
2770 // u1 type_argument_index;
2771 // } path[path_length];
2772 // }
2773 //
2774 bool VM_RedefineClasses::skip_type_annotation_type_path(
2775 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, TRAPS) {
2776
2777 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2778 // not enough room for a path_length let alone the rest of the type_path
2779 log_debug(redefine, class, annotation)("length() is too small for a type_path");
2780 return false;
2781 }
2782
2783 u1 path_length = type_annotations_typeArray->at(byte_i_ref);
2784 byte_i_ref += 1;
2785
2786 log_debug(redefine, class, annotation)("type_path: path_length=%d", path_length);
2787
2788 int calc_path_length = 0;
2789 for (; calc_path_length < path_length; calc_path_length++) {
2790 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) {
2791 // not enough room for a path
2792 log_debug(redefine, class, annotation)
2793 ("length() is too small for path entry %d of %d", calc_path_length, path_length);
2794 return false;
2795 }
2796
2797 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref);
2798 byte_i_ref += 1;
2799 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
2800 byte_i_ref += 1;
2801
2802 log_debug(redefine, class, annotation)
2803 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d",
2804 calc_path_length, type_path_kind, type_argument_index);
2805
2806 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) {
2807 // not enough room for a path
2808 log_debug(redefine, class, annotation)("inconsistent type_path values");
2809 return false;
2810 }
2811 }
2812 assert(path_length == calc_path_length, "sanity check");
2813
2814 return true;
2815 } // end skip_type_annotation_type_path()
2816
2817
2818 // Rewrite constant pool references in the method's stackmap table.
2819 // These "structures" are adapted from the StackMapTable_attribute that
2820 // is described in section 4.8.4 of the 6.0 version of the VM spec
2821 // (dated 2005.10.26):
2822 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2823 //
2824 // stack_map {
2825 // u2 number_of_entries;
2826 // stack_map_frame entries[number_of_entries];
2827 // }
2828 //
2829 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table(
2830 const methodHandle& method, TRAPS) {
2831
2832 if (!method->has_stackmap_table()) {
2833 return;
2834 }
2835
2836 AnnotationArray* stackmap_data = method->stackmap_data();
2837 address stackmap_p = (address)stackmap_data->adr_at(0);
2838 address stackmap_end = stackmap_p + stackmap_data->length();
2839
2840 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries");
2841 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p);
2842 stackmap_p += 2;
2843
2844 log_debug(redefine, class, stackmap)("number_of_entries=%u", number_of_entries);
2845
2846 // walk through each stack_map_frame
2847 u2 calc_number_of_entries = 0;
2848 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) {
2849 // The stack_map_frame structure is a u1 frame_type followed by
2850 // 0 or more bytes of data:
2851 //
2852 // union stack_map_frame {
2853 // same_frame;
2854 // same_locals_1_stack_item_frame;
2855 // same_locals_1_stack_item_frame_extended;
2856 // chop_frame;
2857 // same_frame_extended;
2858 // append_frame;
2859 // full_frame;
2860 // }
2861
2862 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type");
2863 u1 frame_type = *stackmap_p;
2864 stackmap_p++;
2865
2866 // same_frame {
2867 // u1 frame_type = SAME; /* 0-63 */
2868 // }
2869 if (frame_type <= 63) {
2870 // nothing more to do for same_frame
2871 }
2872
2873 // same_locals_1_stack_item_frame {
2874 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */
2875 // verification_type_info stack[1];
2876 // }
2877 else if (frame_type >= 64 && frame_type <= 127) {
2878 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2879 calc_number_of_entries, frame_type, THREAD);
2880 }
2881
2882 // reserved for future use
2883 else if (frame_type >= 128 && frame_type <= 246) {
2884 // nothing more to do for reserved frame_types
2885 }
2886
2887 // same_locals_1_stack_item_frame_extended {
2888 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */
2889 // u2 offset_delta;
2890 // verification_type_info stack[1];
2891 // }
2892 else if (frame_type == 247) {
2893 stackmap_p += 2;
2894 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2895 calc_number_of_entries, frame_type, THREAD);
2896 }
2897
2898 // chop_frame {
2899 // u1 frame_type = CHOP; /* 248-250 */
2900 // u2 offset_delta;
2901 // }
2902 else if (frame_type >= 248 && frame_type <= 250) {
2903 stackmap_p += 2;
2904 }
2905
2906 // same_frame_extended {
2907 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/
2908 // u2 offset_delta;
2909 // }
2910 else if (frame_type == 251) {
2911 stackmap_p += 2;
2912 }
2913
2914 // append_frame {
2915 // u1 frame_type = APPEND; /* 252-254 */
2916 // u2 offset_delta;
2917 // verification_type_info locals[frame_type - 251];
2918 // }
2919 else if (frame_type >= 252 && frame_type <= 254) {
2920 assert(stackmap_p + 2 <= stackmap_end,
2921 "no room for offset_delta");
2922 stackmap_p += 2;
2923 u1 len = frame_type - 251;
2924 for (u1 i = 0; i < len; i++) {
2925 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2926 calc_number_of_entries, frame_type, THREAD);
2927 }
2928 }
2929
2930 // full_frame {
2931 // u1 frame_type = FULL_FRAME; /* 255 */
2932 // u2 offset_delta;
2933 // u2 number_of_locals;
2934 // verification_type_info locals[number_of_locals];
2935 // u2 number_of_stack_items;
2936 // verification_type_info stack[number_of_stack_items];
2937 // }
2938 else if (frame_type == 255) {
2939 assert(stackmap_p + 2 + 2 <= stackmap_end,
2940 "no room for smallest full_frame");
2941 stackmap_p += 2;
2942
2943 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p);
2944 stackmap_p += 2;
2945
2946 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) {
2947 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2948 calc_number_of_entries, frame_type, THREAD);
2949 }
2950
2951 // Use the largest size for the number_of_stack_items, but only get
2952 // the right number of bytes.
2953 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p);
2954 stackmap_p += 2;
2955
2956 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) {
2957 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2958 calc_number_of_entries, frame_type, THREAD);
2959 }
2960 }
2961 } // end while there is a stack_map_frame
2962 assert(number_of_entries == calc_number_of_entries, "sanity check");
2963 } // end rewrite_cp_refs_in_stack_map_table()
2964
2965
2966 // Rewrite constant pool references in the verification type info
2967 // portion of the method's stackmap table. These "structures" are
2968 // adapted from the StackMapTable_attribute that is described in
2969 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26):
2970 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2971 //
2972 // The verification_type_info structure is a u1 tag followed by 0 or
2973 // more bytes of data:
2974 //
2975 // union verification_type_info {
2976 // Top_variable_info;
2977 // Integer_variable_info;
2978 // Float_variable_info;
2979 // Long_variable_info;
2980 // Double_variable_info;
2981 // Null_variable_info;
2982 // UninitializedThis_variable_info;
2983 // Object_variable_info;
2984 // Uninitialized_variable_info;
2985 // }
2986 //
2987 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info(
2988 address& stackmap_p_ref, address stackmap_end, u2 frame_i,
2989 u1 frame_type, TRAPS) {
2990
2991 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag");
2992 u1 tag = *stackmap_p_ref;
2993 stackmap_p_ref++;
2994
2995 switch (tag) {
2996 // Top_variable_info {
2997 // u1 tag = ITEM_Top; /* 0 */
2998 // }
2999 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top
3000 case 0: // fall through
3001
3002 // Integer_variable_info {
3003 // u1 tag = ITEM_Integer; /* 1 */
3004 // }
3005 case ITEM_Integer: // fall through
3006
3007 // Float_variable_info {
3008 // u1 tag = ITEM_Float; /* 2 */
3009 // }
3010 case ITEM_Float: // fall through
3011
3012 // Double_variable_info {
3013 // u1 tag = ITEM_Double; /* 3 */
3014 // }
3015 case ITEM_Double: // fall through
3016
3017 // Long_variable_info {
3018 // u1 tag = ITEM_Long; /* 4 */
3019 // }
3020 case ITEM_Long: // fall through
3021
3022 // Null_variable_info {
3023 // u1 tag = ITEM_Null; /* 5 */
3024 // }
3025 case ITEM_Null: // fall through
3026
3027 // UninitializedThis_variable_info {
3028 // u1 tag = ITEM_UninitializedThis; /* 6 */
3029 // }
3030 case ITEM_UninitializedThis:
3031 // nothing more to do for the above tag types
3032 break;
3033
3034 // Object_variable_info {
3035 // u1 tag = ITEM_Object; /* 7 */
3036 // u2 cpool_index;
3037 // }
3038 case ITEM_Object:
3039 {
3040 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index");
3041 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref);
3042 u2 new_cp_index = find_new_index(cpool_index);
3043 if (new_cp_index != 0) {
3044 log_debug(redefine, class, stackmap)("mapped old cpool_index=%d", cpool_index);
3045 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
3046 cpool_index = new_cp_index;
3047 }
3048 stackmap_p_ref += 2;
3049
3050 log_debug(redefine, class, stackmap)
3051 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i, frame_type, cpool_index);
3052 } break;
3053
3054 // Uninitialized_variable_info {
3055 // u1 tag = ITEM_Uninitialized; /* 8 */
3056 // u2 offset;
3057 // }
3058 case ITEM_Uninitialized:
3059 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset");
3060 stackmap_p_ref += 2;
3061 break;
3062
3063 default:
3064 log_debug(redefine, class, stackmap)("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag);
3065 ShouldNotReachHere();
3066 break;
3067 } // end switch (tag)
3068 } // end rewrite_cp_refs_in_verification_type_info()
3069
3070
3071 // Change the constant pool associated with klass scratch_class to
3072 // scratch_cp. If shrink is true, then scratch_cp_length elements
3073 // are copied from scratch_cp to a smaller constant pool and the
3074 // smaller constant pool is associated with scratch_class.
3075 void VM_RedefineClasses::set_new_constant_pool(
3076 ClassLoaderData* loader_data,
3077 instanceKlassHandle scratch_class, constantPoolHandle scratch_cp,
3078 int scratch_cp_length, TRAPS) {
3079 assert(scratch_cp->length() >= scratch_cp_length, "sanity check");
3080
3081 // scratch_cp is a merged constant pool and has enough space for a
3082 // worst case merge situation. We want to associate the minimum
3083 // sized constant pool with the klass to save space.
3084 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK);
3085 constantPoolHandle smaller_cp(THREAD, cp);
3086
3087 // preserve version() value in the smaller copy
3088 int version = scratch_cp->version();
3089 assert(version != 0, "sanity check");
3090 smaller_cp->set_version(version);
3091
3092 // attach klass to new constant pool
3093 // reference to the cp holder is needed for copy_operands()
3094 smaller_cp->set_pool_holder(scratch_class());
3095
3096 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
3097 if (HAS_PENDING_EXCEPTION) {
3098 // Exception is handled in the caller
3099 loader_data->add_to_deallocate_list(smaller_cp());
3100 return;
3101 }
3102 scratch_cp = smaller_cp;
3103
3104 // attach new constant pool to klass
3105 scratch_class->set_constants(scratch_cp());
3106
3107 int i; // for portability
3108
3109 // update each field in klass to use new constant pool indices as needed
3110 for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) {
3111 jshort cur_index = fs.name_index();
3112 jshort new_index = find_new_index(cur_index);
3113 if (new_index != 0) {
3114 log_trace(redefine, class, constantpool)("field-name_index change: %d to %d", cur_index, new_index);
3115 fs.set_name_index(new_index);
3116 }
3117 cur_index = fs.signature_index();
3118 new_index = find_new_index(cur_index);
3119 if (new_index != 0) {
3120 log_trace(redefine, class, constantpool)("field-signature_index change: %d to %d", cur_index, new_index);
3121 fs.set_signature_index(new_index);
3122 }
3123 cur_index = fs.initval_index();
3124 new_index = find_new_index(cur_index);
3125 if (new_index != 0) {
3126 log_trace(redefine, class, constantpool)("field-initval_index change: %d to %d", cur_index, new_index);
3127 fs.set_initval_index(new_index);
3128 }
3129 cur_index = fs.generic_signature_index();
3130 new_index = find_new_index(cur_index);
3131 if (new_index != 0) {
3132 log_trace(redefine, class, constantpool)("field-generic_signature change: %d to %d", cur_index, new_index);
3133 fs.set_generic_signature_index(new_index);
3134 }
3135 } // end for each field
3136
3137 // Update constant pool indices in the inner classes info to use
3138 // new constant indices as needed. The inner classes info is a
3139 // quadruple:
3140 // (inner_class_info, outer_class_info, inner_name, inner_access_flags)
3141 InnerClassesIterator iter(scratch_class);
3142 for (; !iter.done(); iter.next()) {
3143 int cur_index = iter.inner_class_info_index();
3144 if (cur_index == 0) {
3145 continue; // JVM spec. allows null inner class refs so skip it
3146 }
3147 int new_index = find_new_index(cur_index);
3148 if (new_index != 0) {
3149 log_trace(redefine, class, constantpool)("inner_class_info change: %d to %d", cur_index, new_index);
3150 iter.set_inner_class_info_index(new_index);
3151 }
3152 cur_index = iter.outer_class_info_index();
3153 new_index = find_new_index(cur_index);
3154 if (new_index != 0) {
3155 log_trace(redefine, class, constantpool)("outer_class_info change: %d to %d", cur_index, new_index);
3156 iter.set_outer_class_info_index(new_index);
3157 }
3158 cur_index = iter.inner_name_index();
3159 new_index = find_new_index(cur_index);
3160 if (new_index != 0) {
3161 log_trace(redefine, class, constantpool)("inner_name change: %d to %d", cur_index, new_index);
3162 iter.set_inner_name_index(new_index);
3163 }
3164 } // end for each inner class
3165
3166 // Attach each method in klass to the new constant pool and update
3167 // to use new constant pool indices as needed:
3168 Array<Method*>* methods = scratch_class->methods();
3169 for (i = methods->length() - 1; i >= 0; i--) {
3170 methodHandle method(THREAD, methods->at(i));
3171 method->set_constants(scratch_cp());
3172
3173 int new_index = find_new_index(method->name_index());
3174 if (new_index != 0) {
3175 log_trace(redefine, class, constantpool)
3176 ("method-name_index change: %d to %d", method->name_index(), new_index);
3177 method->set_name_index(new_index);
3178 }
3179 new_index = find_new_index(method->signature_index());
3180 if (new_index != 0) {
3181 log_trace(redefine, class, constantpool)
3182 ("method-signature_index change: %d to %d", method->signature_index(), new_index);
3183 method->set_signature_index(new_index);
3184 }
3185 new_index = find_new_index(method->generic_signature_index());
3186 if (new_index != 0) {
3187 log_trace(redefine, class, constantpool)
3188 ("method-generic_signature_index change: %d to %d", method->generic_signature_index(), new_index);
3189 method->set_generic_signature_index(new_index);
3190 }
3191
3192 // Update constant pool indices in the method's checked exception
3193 // table to use new constant indices as needed.
3194 int cext_length = method->checked_exceptions_length();
3195 if (cext_length > 0) {
3196 CheckedExceptionElement * cext_table =
3197 method->checked_exceptions_start();
3198 for (int j = 0; j < cext_length; j++) {
3199 int cur_index = cext_table[j].class_cp_index;
3200 int new_index = find_new_index(cur_index);
3201 if (new_index != 0) {
3202 log_trace(redefine, class, constantpool)("cext-class_cp_index change: %d to %d", cur_index, new_index);
3203 cext_table[j].class_cp_index = (u2)new_index;
3204 }
3205 } // end for each checked exception table entry
3206 } // end if there are checked exception table entries
3207
3208 // Update each catch type index in the method's exception table
3209 // to use new constant pool indices as needed. The exception table
3210 // holds quadruple entries of the form:
3211 // (beg_bci, end_bci, handler_bci, klass_index)
3212
3213 ExceptionTable ex_table(method());
3214 int ext_length = ex_table.length();
3215
3216 for (int j = 0; j < ext_length; j ++) {
3217 int cur_index = ex_table.catch_type_index(j);
3218 int new_index = find_new_index(cur_index);
3219 if (new_index != 0) {
3220 log_trace(redefine, class, constantpool)("ext-klass_index change: %d to %d", cur_index, new_index);
3221 ex_table.set_catch_type_index(j, new_index);
3222 }
3223 } // end for each exception table entry
3224
3225 // Update constant pool indices in the method's local variable
3226 // table to use new constant indices as needed. The local variable
3227 // table hold sextuple entries of the form:
3228 // (start_pc, length, name_index, descriptor_index, signature_index, slot)
3229 int lvt_length = method->localvariable_table_length();
3230 if (lvt_length > 0) {
3231 LocalVariableTableElement * lv_table =
3232 method->localvariable_table_start();
3233 for (int j = 0; j < lvt_length; j++) {
3234 int cur_index = lv_table[j].name_cp_index;
3235 int new_index = find_new_index(cur_index);
3236 if (new_index != 0) {
3237 log_trace(redefine, class, constantpool)("lvt-name_cp_index change: %d to %d", cur_index, new_index);
3238 lv_table[j].name_cp_index = (u2)new_index;
3239 }
3240 cur_index = lv_table[j].descriptor_cp_index;
3241 new_index = find_new_index(cur_index);
3242 if (new_index != 0) {
3243 log_trace(redefine, class, constantpool)("lvt-descriptor_cp_index change: %d to %d", cur_index, new_index);
3244 lv_table[j].descriptor_cp_index = (u2)new_index;
3245 }
3246 cur_index = lv_table[j].signature_cp_index;
3247 new_index = find_new_index(cur_index);
3248 if (new_index != 0) {
3249 log_trace(redefine, class, constantpool)("lvt-signature_cp_index change: %d to %d", cur_index, new_index);
3250 lv_table[j].signature_cp_index = (u2)new_index;
3251 }
3252 } // end for each local variable table entry
3253 } // end if there are local variable table entries
3254
3255 rewrite_cp_refs_in_stack_map_table(method, THREAD);
3256 } // end for each method
3257 } // end set_new_constant_pool()
3258
3259
3260 // Unevolving classes may point to methods of the_class directly
3261 // from their constant pool caches, itables, and/or vtables. We
3262 // use the ClassLoaderDataGraph::classes_do() facility and this helper
3263 // to fix up these pointers.
3264
3265 // Adjust cpools and vtables closure
3266 void VM_RedefineClasses::AdjustCpoolCacheAndVtable::do_klass(Klass* k) {
3267
3268 // This is a very busy routine. We don't want too much tracing
3269 // printed out.
3270 bool trace_name_printed = false;
3271 InstanceKlass *the_class = InstanceKlass::cast(_the_class_oop);
3272
3273 // If the class being redefined is java.lang.Object, we need to fix all
3274 // array class vtables also
3275 if (k->is_array_klass() && _the_class_oop == SystemDictionary::Object_klass()) {
3276 k->vtable()->adjust_method_entries(the_class, &trace_name_printed);
3277
3278 } else if (k->is_instance_klass()) {
3279 HandleMark hm(_thread);
3280 InstanceKlass *ik = InstanceKlass::cast(k);
3281
3282 // HotSpot specific optimization! HotSpot does not currently
3283 // support delegation from the bootstrap class loader to a
3284 // user-defined class loader. This means that if the bootstrap
3285 // class loader is the initiating class loader, then it will also
3286 // be the defining class loader. This also means that classes
3287 // loaded by the bootstrap class loader cannot refer to classes
3288 // loaded by a user-defined class loader. Note: a user-defined
3289 // class loader can delegate to the bootstrap class loader.
3290 //
3291 // If the current class being redefined has a user-defined class
3292 // loader as its defining class loader, then we can skip all
3293 // classes loaded by the bootstrap class loader.
3294 bool is_user_defined =
3295 InstanceKlass::cast(_the_class_oop)->class_loader() != NULL;
3296 if (is_user_defined && ik->class_loader() == NULL) {
3297 return;
3298 }
3299
3300 // Fix the vtable embedded in the_class and subclasses of the_class,
3301 // if one exists. We discard scratch_class and we don't keep an
3302 // InstanceKlass around to hold obsolete methods so we don't have
3303 // any other InstanceKlass embedded vtables to update. The vtable
3304 // holds the Method*s for virtual (but not final) methods.
3305 // Default methods, or concrete methods in interfaces are stored
3306 // in the vtable, so if an interface changes we need to check
3307 // adjust_method_entries() for every InstanceKlass, which will also
3308 // adjust the default method vtable indices.
3309 // We also need to adjust any default method entries that are
3310 // not yet in the vtable, because the vtable setup is in progress.
3311 // This must be done after we adjust the default_methods and
3312 // default_vtable_indices for methods already in the vtable.
3313 // If redefining Unsafe, walk all the vtables looking for entries.
3314 if (ik->vtable_length() > 0 && (_the_class_oop->is_interface()
3315 || _the_class_oop == SystemDictionary::internal_Unsafe_klass()
3316 || ik->is_subtype_of(_the_class_oop))) {
3317 // ik->vtable() creates a wrapper object; rm cleans it up
3318 ResourceMark rm(_thread);
3319
3320 ik->vtable()->adjust_method_entries(the_class, &trace_name_printed);
3321 ik->adjust_default_methods(the_class, &trace_name_printed);
3322 }
3323
3324 // If the current class has an itable and we are either redefining an
3325 // interface or if the current class is a subclass of the_class, then
3326 // we potentially have to fix the itable. If we are redefining an
3327 // interface, then we have to call adjust_method_entries() for
3328 // every InstanceKlass that has an itable since there isn't a
3329 // subclass relationship between an interface and an InstanceKlass.
3330 // If redefining Unsafe, walk all the itables looking for entries.
3331 if (ik->itable_length() > 0 && (_the_class_oop->is_interface()
3332 || _the_class_oop == SystemDictionary::internal_Unsafe_klass()
3333 || ik->is_subclass_of(_the_class_oop))) {
3334 // ik->itable() creates a wrapper object; rm cleans it up
3335 ResourceMark rm(_thread);
3336
3337 ik->itable()->adjust_method_entries(the_class, &trace_name_printed);
3338 }
3339
3340 // The constant pools in other classes (other_cp) can refer to
3341 // methods in the_class. We have to update method information in
3342 // other_cp's cache. If other_cp has a previous version, then we
3343 // have to repeat the process for each previous version. The
3344 // constant pool cache holds the Method*s for non-virtual
3345 // methods and for virtual, final methods.
3346 //
3347 // Special case: if the current class is the_class, then new_cp
3348 // has already been attached to the_class and old_cp has already
3349 // been added as a previous version. The new_cp doesn't have any
3350 // cached references to old methods so it doesn't need to be
3351 // updated. We can simply start with the previous version(s) in
3352 // that case.
3353 constantPoolHandle other_cp;
3354 ConstantPoolCache* cp_cache;
3355
3356 if (ik != _the_class_oop) {
3357 // this klass' constant pool cache may need adjustment
3358 other_cp = constantPoolHandle(ik->constants());
3359 cp_cache = other_cp->cache();
3360 if (cp_cache != NULL) {
3361 cp_cache->adjust_method_entries(the_class, &trace_name_printed);
3362 }
3363 }
3364
3365 // the previous versions' constant pool caches may need adjustment
3366 for (InstanceKlass* pv_node = ik->previous_versions();
3367 pv_node != NULL;
3368 pv_node = pv_node->previous_versions()) {
3369 cp_cache = pv_node->constants()->cache();
3370 if (cp_cache != NULL) {
3371 cp_cache->adjust_method_entries(pv_node, &trace_name_printed);
3372 }
3373 }
3374 }
3375 }
3376
3377 // Clean method data for this class
3378 void VM_RedefineClasses::MethodDataCleaner::do_klass(Klass* k) {
3379 if (k->is_instance_klass()) {
3380 InstanceKlass *ik = InstanceKlass::cast(k);
3381 // Clean MethodData of this class's methods so they don't refer to
3382 // old methods that are no longer running.
3383 Array<Method*>* methods = ik->methods();
3384 int num_methods = methods->length();
3385 for (int index = 0; index < num_methods; ++index) {
3386 if (methods->at(index)->method_data() != NULL) {
3387 methods->at(index)->method_data()->clean_weak_method_links();
3388 }
3389 }
3390 }
3391 }
3392
3393 void VM_RedefineClasses::update_jmethod_ids() {
3394 for (int j = 0; j < _matching_methods_length; ++j) {
3395 Method* old_method = _matching_old_methods[j];
3396 jmethodID jmid = old_method->find_jmethod_id_or_null();
3397 if (jmid != NULL) {
3398 // There is a jmethodID, change it to point to the new method
3399 methodHandle new_method_h(_matching_new_methods[j]);
3400 Method::change_method_associated_with_jmethod_id(jmid, new_method_h());
3401 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j],
3402 "should be replaced");
3403 }
3404 }
3405 }
3406
3407 int VM_RedefineClasses::check_methods_and_mark_as_obsolete() {
3408 int emcp_method_count = 0;
3409 int obsolete_count = 0;
3410 int old_index = 0;
3411 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
3412 Method* old_method = _matching_old_methods[j];
3413 Method* new_method = _matching_new_methods[j];
3414 Method* old_array_method;
3415
3416 // Maintain an old_index into the _old_methods array by skipping
3417 // deleted methods
3418 while ((old_array_method = _old_methods->at(old_index)) != old_method) {
3419 ++old_index;
3420 }
3421
3422 if (MethodComparator::methods_EMCP(old_method, new_method)) {
3423 // The EMCP definition from JSR-163 requires the bytecodes to be
3424 // the same with the exception of constant pool indices which may
3425 // differ. However, the constants referred to by those indices
3426 // must be the same.
3427 //
3428 // We use methods_EMCP() for comparison since constant pool
3429 // merging can remove duplicate constant pool entries that were
3430 // present in the old method and removed from the rewritten new
3431 // method. A faster binary comparison function would consider the
3432 // old and new methods to be different when they are actually
3433 // EMCP.
3434 //
3435 // The old and new methods are EMCP and you would think that we
3436 // could get rid of one of them here and now and save some space.
3437 // However, the concept of EMCP only considers the bytecodes and
3438 // the constant pool entries in the comparison. Other things,
3439 // e.g., the line number table (LNT) or the local variable table
3440 // (LVT) don't count in the comparison. So the new (and EMCP)
3441 // method can have a new LNT that we need so we can't just
3442 // overwrite the new method with the old method.
3443 //
3444 // When this routine is called, we have already attached the new
3445 // methods to the_class so the old methods are effectively
3446 // overwritten. However, if an old method is still executing,
3447 // then the old method cannot be collected until sometime after
3448 // the old method call has returned. So the overwriting of old
3449 // methods by new methods will save us space except for those
3450 // (hopefully few) old methods that are still executing.
3451 //
3452 // A method refers to a ConstMethod* and this presents another
3453 // possible avenue to space savings. The ConstMethod* in the
3454 // new method contains possibly new attributes (LNT, LVT, etc).
3455 // At first glance, it seems possible to save space by replacing
3456 // the ConstMethod* in the old method with the ConstMethod*
3457 // from the new method. The old and new methods would share the
3458 // same ConstMethod* and we would save the space occupied by
3459 // the old ConstMethod*. However, the ConstMethod* contains
3460 // a back reference to the containing method. Sharing the
3461 // ConstMethod* between two methods could lead to confusion in
3462 // the code that uses the back reference. This would lead to
3463 // brittle code that could be broken in non-obvious ways now or
3464 // in the future.
3465 //
3466 // Another possibility is to copy the ConstMethod* from the new
3467 // method to the old method and then overwrite the new method with
3468 // the old method. Since the ConstMethod* contains the bytecodes
3469 // for the method embedded in the oop, this option would change
3470 // the bytecodes out from under any threads executing the old
3471 // method and make the thread's bcp invalid. Since EMCP requires
3472 // that the bytecodes be the same modulo constant pool indices, it
3473 // is straight forward to compute the correct new bcp in the new
3474 // ConstMethod* from the old bcp in the old ConstMethod*. The
3475 // time consuming part would be searching all the frames in all
3476 // of the threads to find all of the calls to the old method.
3477 //
3478 // It looks like we will have to live with the limited savings
3479 // that we get from effectively overwriting the old methods
3480 // when the new methods are attached to the_class.
3481
3482 // Count number of methods that are EMCP. The method will be marked
3483 // old but not obsolete if it is EMCP.
3484 emcp_method_count++;
3485
3486 // An EMCP method is _not_ obsolete. An obsolete method has a
3487 // different jmethodID than the current method. An EMCP method
3488 // has the same jmethodID as the current method. Having the
3489 // same jmethodID for all EMCP versions of a method allows for
3490 // a consistent view of the EMCP methods regardless of which
3491 // EMCP method you happen to have in hand. For example, a
3492 // breakpoint set in one EMCP method will work for all EMCP
3493 // versions of the method including the current one.
3494 } else {
3495 // mark obsolete methods as such
3496 old_method->set_is_obsolete();
3497 obsolete_count++;
3498
3499 // obsolete methods need a unique idnum so they become new entries in
3500 // the jmethodID cache in InstanceKlass
3501 assert(old_method->method_idnum() == new_method->method_idnum(), "must match");
3502 u2 num = InstanceKlass::cast(_the_class_oop)->next_method_idnum();
3503 if (num != ConstMethod::UNSET_IDNUM) {
3504 old_method->set_method_idnum(num);
3505 }
3506
3507 // With tracing we try not to "yack" too much. The position of
3508 // this trace assumes there are fewer obsolete methods than
3509 // EMCP methods.
3510 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) {
3511 ResourceMark rm;
3512 log_trace(redefine, class, obsolete, mark)
3513 ("mark %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string());
3514 }
3515 }
3516 old_method->set_is_old();
3517 }
3518 for (int i = 0; i < _deleted_methods_length; ++i) {
3519 Method* old_method = _deleted_methods[i];
3520
3521 assert(!old_method->has_vtable_index(),
3522 "cannot delete methods with vtable entries");;
3523
3524 // Mark all deleted methods as old, obsolete and deleted
3525 old_method->set_is_deleted();
3526 old_method->set_is_old();
3527 old_method->set_is_obsolete();
3528 ++obsolete_count;
3529 // With tracing we try not to "yack" too much. The position of
3530 // this trace assumes there are fewer obsolete methods than
3531 // EMCP methods.
3532 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) {
3533 ResourceMark rm;
3534 log_trace(redefine, class, obsolete, mark)
3535 ("mark deleted %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string());
3536 }
3537 }
3538 assert((emcp_method_count + obsolete_count) == _old_methods->length(),
3539 "sanity check");
3540 log_trace(redefine, class, obsolete, mark)("EMCP_cnt=%d, obsolete_cnt=%d", emcp_method_count, obsolete_count);
3541 return emcp_method_count;
3542 }
3543
3544 // This internal class transfers the native function registration from old methods
3545 // to new methods. It is designed to handle both the simple case of unchanged
3546 // native methods and the complex cases of native method prefixes being added and/or
3547 // removed.
3548 // It expects only to be used during the VM_RedefineClasses op (a safepoint).
3549 //
3550 // This class is used after the new methods have been installed in "the_class".
3551 //
3552 // So, for example, the following must be handled. Where 'm' is a method and
3553 // a number followed by an underscore is a prefix.
3554 //
3555 // Old Name New Name
3556 // Simple transfer to new method m -> m
3557 // Add prefix m -> 1_m
3558 // Remove prefix 1_m -> m
3559 // Simultaneous add of prefixes m -> 3_2_1_m
3560 // Simultaneous removal of prefixes 3_2_1_m -> m
3561 // Simultaneous add and remove 1_m -> 2_m
3562 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m
3563 //
3564 class TransferNativeFunctionRegistration {
3565 private:
3566 instanceKlassHandle the_class;
3567 int prefix_count;
3568 char** prefixes;
3569
3570 // Recursively search the binary tree of possibly prefixed method names.
3571 // Iteration could be used if all agents were well behaved. Full tree walk is
3572 // more resilent to agents not cleaning up intermediate methods.
3573 // Branch at each depth in the binary tree is:
3574 // (1) without the prefix.
3575 // (2) with the prefix.
3576 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
3577 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len,
3578 Symbol* signature) {
3579 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len);
3580 if (name_symbol != NULL) {
3581 Method* method = the_class()->lookup_method(name_symbol, signature);
3582 if (method != NULL) {
3583 // Even if prefixed, intermediate methods must exist.
3584 if (method->is_native()) {
3585 // Wahoo, we found a (possibly prefixed) version of the method, return it.
3586 return method;
3587 }
3588 if (depth < prefix_count) {
3589 // Try applying further prefixes (other than this one).
3590 method = search_prefix_name_space(depth+1, name_str, name_len, signature);
3591 if (method != NULL) {
3592 return method; // found
3593 }
3594
3595 // Try adding this prefix to the method name and see if it matches
3596 // another method name.
3597 char* prefix = prefixes[depth];
3598 size_t prefix_len = strlen(prefix);
3599 size_t trial_len = name_len + prefix_len;
3600 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
3601 strcpy(trial_name_str, prefix);
3602 strcat(trial_name_str, name_str);
3603 method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
3604 signature);
3605 if (method != NULL) {
3606 // If found along this branch, it was prefixed, mark as such
3607 method->set_is_prefixed_native();
3608 return method; // found
3609 }
3610 }
3611 }
3612 }
3613 return NULL; // This whole branch bore nothing
3614 }
3615
3616 // Return the method name with old prefixes stripped away.
3617 char* method_name_without_prefixes(Method* method) {
3618 Symbol* name = method->name();
3619 char* name_str = name->as_utf8();
3620
3621 // Old prefixing may be defunct, strip prefixes, if any.
3622 for (int i = prefix_count-1; i >= 0; i--) {
3623 char* prefix = prefixes[i];
3624 size_t prefix_len = strlen(prefix);
3625 if (strncmp(prefix, name_str, prefix_len) == 0) {
3626 name_str += prefix_len;
3627 }
3628 }
3629 return name_str;
3630 }
3631
3632 // Strip any prefixes off the old native method, then try to find a
3633 // (possibly prefixed) new native that matches it.
3634 Method* strip_and_search_for_new_native(Method* method) {
3635 ResourceMark rm;
3636 char* name_str = method_name_without_prefixes(method);
3637 return search_prefix_name_space(0, name_str, strlen(name_str),
3638 method->signature());
3639 }
3640
3641 public:
3642
3643 // Construct a native method transfer processor for this class.
3644 TransferNativeFunctionRegistration(instanceKlassHandle _the_class) {
3645 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
3646
3647 the_class = _the_class;
3648 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
3649 }
3650
3651 // Attempt to transfer any of the old or deleted methods that are native
3652 void transfer_registrations(Method** old_methods, int methods_length) {
3653 for (int j = 0; j < methods_length; j++) {
3654 Method* old_method = old_methods[j];
3655
3656 if (old_method->is_native() && old_method->has_native_function()) {
3657 Method* new_method = strip_and_search_for_new_native(old_method);
3658 if (new_method != NULL) {
3659 // Actually set the native function in the new method.
3660 // Redefine does not send events (except CFLH), certainly not this
3661 // behind the scenes re-registration.
3662 new_method->set_native_function(old_method->native_function(),
3663 !Method::native_bind_event_is_interesting);
3664 }
3665 }
3666 }
3667 }
3668 };
3669
3670 // Don't lose the association between a native method and its JNI function.
3671 void VM_RedefineClasses::transfer_old_native_function_registrations(instanceKlassHandle the_class) {
3672 TransferNativeFunctionRegistration transfer(the_class);
3673 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length);
3674 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length);
3675 }
3676
3677 // Deoptimize all compiled code that depends on this class.
3678 //
3679 // If the can_redefine_classes capability is obtained in the onload
3680 // phase then the compiler has recorded all dependencies from startup.
3681 // In that case we need only deoptimize and throw away all compiled code
3682 // that depends on the class.
3683 //
3684 // If can_redefine_classes is obtained sometime after the onload
3685 // phase then the dependency information may be incomplete. In that case
3686 // the first call to RedefineClasses causes all compiled code to be
3687 // thrown away. As can_redefine_classes has been obtained then
3688 // all future compilations will record dependencies so second and
3689 // subsequent calls to RedefineClasses need only throw away code
3690 // that depends on the class.
3691 //
3692 void VM_RedefineClasses::flush_dependent_code(instanceKlassHandle k_h, TRAPS) {
3693 assert_locked_or_safepoint(Compile_lock);
3694
3695 // All dependencies have been recorded from startup or this is a second or
3696 // subsequent use of RedefineClasses
3697 if (JvmtiExport::all_dependencies_are_recorded()) {
3698 CodeCache::flush_evol_dependents_on(k_h);
3699 } else {
3700 CodeCache::mark_all_nmethods_for_deoptimization();
3701
3702 ResourceMark rm(THREAD);
3703 DeoptimizationMarker dm;
3704
3705 // Deoptimize all activations depending on marked nmethods
3706 Deoptimization::deoptimize_dependents();
3707
3708 // Make the dependent methods not entrant
3709 CodeCache::make_marked_nmethods_not_entrant();
3710
3711 // From now on we know that the dependency information is complete
3712 JvmtiExport::set_all_dependencies_are_recorded(true);
3713 }
3714 }
3715
3716 void VM_RedefineClasses::compute_added_deleted_matching_methods() {
3717 Method* old_method;
3718 Method* new_method;
3719
3720 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3721 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3722 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length());
3723 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3724
3725 _matching_methods_length = 0;
3726 _deleted_methods_length = 0;
3727 _added_methods_length = 0;
3728
3729 int nj = 0;
3730 int oj = 0;
3731 while (true) {
3732 if (oj >= _old_methods->length()) {
3733 if (nj >= _new_methods->length()) {
3734 break; // we've looked at everything, done
3735 }
3736 // New method at the end
3737 new_method = _new_methods->at(nj);
3738 _added_methods[_added_methods_length++] = new_method;
3739 ++nj;
3740 } else if (nj >= _new_methods->length()) {
3741 // Old method, at the end, is deleted
3742 old_method = _old_methods->at(oj);
3743 _deleted_methods[_deleted_methods_length++] = old_method;
3744 ++oj;
3745 } else {
3746 old_method = _old_methods->at(oj);
3747 new_method = _new_methods->at(nj);
3748 if (old_method->name() == new_method->name()) {
3749 if (old_method->signature() == new_method->signature()) {
3750 _matching_old_methods[_matching_methods_length ] = old_method;
3751 _matching_new_methods[_matching_methods_length++] = new_method;
3752 ++nj;
3753 ++oj;
3754 } else {
3755 // added overloaded have already been moved to the end,
3756 // so this is a deleted overloaded method
3757 _deleted_methods[_deleted_methods_length++] = old_method;
3758 ++oj;
3759 }
3760 } else { // names don't match
3761 if (old_method->name()->fast_compare(new_method->name()) > 0) {
3762 // new method
3763 _added_methods[_added_methods_length++] = new_method;
3764 ++nj;
3765 } else {
3766 // deleted method
3767 _deleted_methods[_deleted_methods_length++] = old_method;
3768 ++oj;
3769 }
3770 }
3771 }
3772 }
3773 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
3774 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
3775 }
3776
3777
3778 void VM_RedefineClasses::swap_annotations(instanceKlassHandle the_class,
3779 instanceKlassHandle scratch_class) {
3780 // Swap annotation fields values
3781 Annotations* old_annotations = the_class->annotations();
3782 the_class->set_annotations(scratch_class->annotations());
3783 scratch_class->set_annotations(old_annotations);
3784 }
3785
3786
3787 // Install the redefinition of a class:
3788 // - house keeping (flushing breakpoints and caches, deoptimizing
3789 // dependent compiled code)
3790 // - replacing parts in the_class with parts from scratch_class
3791 // - adding a weak reference to track the obsolete but interesting
3792 // parts of the_class
3793 // - adjusting constant pool caches and vtables in other classes
3794 // that refer to methods in the_class. These adjustments use the
3795 // ClassLoaderDataGraph::classes_do() facility which only allows
3796 // a helper method to be specified. The interesting parameters
3797 // that we would like to pass to the helper method are saved in
3798 // static global fields in the VM operation.
3799 void VM_RedefineClasses::redefine_single_class(jclass the_jclass,
3800 Klass* scratch_class_oop, TRAPS) {
3801
3802 HandleMark hm(THREAD); // make sure handles from this call are freed
3803
3804 if (log_is_enabled(Info, redefine, class, timer)) {
3805 _timer_rsc_phase1.start();
3806 }
3807
3808 instanceKlassHandle scratch_class(THREAD, scratch_class_oop);
3809 instanceKlassHandle the_class(THREAD, get_ik(the_jclass));
3810
3811 // Remove all breakpoints in methods of this class
3812 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
3813 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class());
3814
3815 // Deoptimize all compiled code that depends on this class
3816 flush_dependent_code(the_class, THREAD);
3817
3818 _old_methods = the_class->methods();
3819 _new_methods = scratch_class->methods();
3820 _the_class_oop = the_class();
3821 compute_added_deleted_matching_methods();
3822 update_jmethod_ids();
3823
3824 // Attach new constant pool to the original klass. The original
3825 // klass still refers to the old constant pool (for now).
3826 scratch_class->constants()->set_pool_holder(the_class());
3827
3828 #if 0
3829 // In theory, with constant pool merging in place we should be able
3830 // to save space by using the new, merged constant pool in place of
3831 // the old constant pool(s). By "pool(s)" I mean the constant pool in
3832 // the klass version we are replacing now and any constant pool(s) in
3833 // previous versions of klass. Nice theory, doesn't work in practice.
3834 // When this code is enabled, even simple programs throw NullPointer
3835 // exceptions. I'm guessing that this is caused by some constant pool
3836 // cache difference between the new, merged constant pool and the
3837 // constant pool that was just being used by the klass. I'm keeping
3838 // this code around to archive the idea, but the code has to remain
3839 // disabled for now.
3840
3841 // Attach each old method to the new constant pool. This can be
3842 // done here since we are past the bytecode verification and
3843 // constant pool optimization phases.
3844 for (int i = _old_methods->length() - 1; i >= 0; i--) {
3845 Method* method = _old_methods->at(i);
3846 method->set_constants(scratch_class->constants());
3847 }
3848
3849 // NOTE: this doesn't work because you can redefine the same class in two
3850 // threads, each getting their own constant pool data appended to the
3851 // original constant pool. In order for the new methods to work when they
3852 // become old methods, they need to keep their updated copy of the constant pool.
3853
3854 {
3855 // walk all previous versions of the klass
3856 InstanceKlass *ik = (InstanceKlass *)the_class();
3857 PreviousVersionWalker pvw(ik);
3858 instanceKlassHandle ikh;
3859 do {
3860 ikh = pvw.next_previous_version();
3861 if (!ikh.is_null()) {
3862 ik = ikh();
3863
3864 // attach previous version of klass to the new constant pool
3865 ik->set_constants(scratch_class->constants());
3866
3867 // Attach each method in the previous version of klass to the
3868 // new constant pool
3869 Array<Method*>* prev_methods = ik->methods();
3870 for (int i = prev_methods->length() - 1; i >= 0; i--) {
3871 Method* method = prev_methods->at(i);
3872 method->set_constants(scratch_class->constants());
3873 }
3874 }
3875 } while (!ikh.is_null());
3876 }
3877 #endif
3878
3879 // Replace methods and constantpool
3880 the_class->set_methods(_new_methods);
3881 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods,
3882 // and to be able to undo operation easily.
3883
3884 Array<int>* old_ordering = the_class->method_ordering();
3885 the_class->set_method_ordering(scratch_class->method_ordering());
3886 scratch_class->set_method_ordering(old_ordering);
3887
3888 ConstantPool* old_constants = the_class->constants();
3889 the_class->set_constants(scratch_class->constants());
3890 scratch_class->set_constants(old_constants); // See the previous comment.
3891 #if 0
3892 // We are swapping the guts of "the new class" with the guts of "the
3893 // class". Since the old constant pool has just been attached to "the
3894 // new class", it seems logical to set the pool holder in the old
3895 // constant pool also. However, doing this will change the observable
3896 // class hierarchy for any old methods that are still executing. A
3897 // method can query the identity of its "holder" and this query uses
3898 // the method's constant pool link to find the holder. The change in
3899 // holding class from "the class" to "the new class" can confuse
3900 // things.
3901 //
3902 // Setting the old constant pool's holder will also cause
3903 // verification done during vtable initialization below to fail.
3904 // During vtable initialization, the vtable's class is verified to be
3905 // a subtype of the method's holder. The vtable's class is "the
3906 // class" and the method's holder is gotten from the constant pool
3907 // link in the method itself. For "the class"'s directly implemented
3908 // methods, the method holder is "the class" itself (as gotten from
3909 // the new constant pool). The check works fine in this case. The
3910 // check also works fine for methods inherited from super classes.
3911 //
3912 // Miranda methods are a little more complicated. A miranda method is
3913 // provided by an interface when the class implementing the interface
3914 // does not provide its own method. These interfaces are implemented
3915 // internally as an InstanceKlass. These special instanceKlasses
3916 // share the constant pool of the class that "implements" the
3917 // interface. By sharing the constant pool, the method holder of a
3918 // miranda method is the class that "implements" the interface. In a
3919 // non-redefine situation, the subtype check works fine. However, if
3920 // the old constant pool's pool holder is modified, then the check
3921 // fails because there is no class hierarchy relationship between the
3922 // vtable's class and "the new class".
3923
3924 old_constants->set_pool_holder(scratch_class());
3925 #endif
3926
3927 // track number of methods that are EMCP for add_previous_version() call below
3928 int emcp_method_count = check_methods_and_mark_as_obsolete();
3929 transfer_old_native_function_registrations(the_class);
3930
3931 // The class file bytes from before any retransformable agents mucked
3932 // with them was cached on the scratch class, move to the_class.
3933 // Note: we still want to do this if nothing needed caching since it
3934 // should get cleared in the_class too.
3935 if (the_class->get_cached_class_file_bytes() == 0) {
3936 // the_class doesn't have a cache yet so copy it
3937 the_class->set_cached_class_file(scratch_class->get_cached_class_file());
3938 }
3939 else if (scratch_class->get_cached_class_file_bytes() !=
3940 the_class->get_cached_class_file_bytes()) {
3941 // The same class can be present twice in the scratch classes list or there
3942 // are multiple concurrent RetransformClasses calls on different threads.
3943 // In such cases we have to deallocate scratch_class cached_class_file.
3944 os::free(scratch_class->get_cached_class_file());
3945 }
3946
3947 // NULL out in scratch class to not delete twice. The class to be redefined
3948 // always owns these bytes.
3949 scratch_class->set_cached_class_file(NULL);
3950
3951 // Replace inner_classes
3952 Array<u2>* old_inner_classes = the_class->inner_classes();
3953 the_class->set_inner_classes(scratch_class->inner_classes());
3954 scratch_class->set_inner_classes(old_inner_classes);
3955
3956 // Initialize the vtable and interface table after
3957 // methods have been rewritten
3958 {
3959 ResourceMark rm(THREAD);
3960 // no exception should happen here since we explicitly
3961 // do not check loader constraints.
3962 // compare_and_normalize_class_versions has already checked:
3963 // - classloaders unchanged, signatures unchanged
3964 // - all instanceKlasses for redefined classes reused & contents updated
3965 the_class->vtable()->initialize_vtable(false, THREAD);
3966 the_class->itable()->initialize_itable(false, THREAD);
3967 assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())), "redefine exception");
3968 }
3969
3970 // Leave arrays of jmethodIDs and itable index cache unchanged
3971
3972 // Copy the "source file name" attribute from new class version
3973 the_class->set_source_file_name_index(
3974 scratch_class->source_file_name_index());
3975
3976 // Copy the "source debug extension" attribute from new class version
3977 the_class->set_source_debug_extension(
3978 scratch_class->source_debug_extension(),
3979 scratch_class->source_debug_extension() == NULL ? 0 :
3980 (int)strlen(scratch_class->source_debug_extension()));
3981
3982 // Use of javac -g could be different in the old and the new
3983 if (scratch_class->access_flags().has_localvariable_table() !=
3984 the_class->access_flags().has_localvariable_table()) {
3985
3986 AccessFlags flags = the_class->access_flags();
3987 if (scratch_class->access_flags().has_localvariable_table()) {
3988 flags.set_has_localvariable_table();
3989 } else {
3990 flags.clear_has_localvariable_table();
3991 }
3992 the_class->set_access_flags(flags);
3993 }
3994
3995 swap_annotations(the_class, scratch_class);
3996
3997 // Replace minor version number of class file
3998 u2 old_minor_version = the_class->minor_version();
3999 the_class->set_minor_version(scratch_class->minor_version());
4000 scratch_class->set_minor_version(old_minor_version);
4001
4002 // Replace major version number of class file
4003 u2 old_major_version = the_class->major_version();
4004 the_class->set_major_version(scratch_class->major_version());
4005 scratch_class->set_major_version(old_major_version);
4006
4007 // Replace CP indexes for class and name+type of enclosing method
4008 u2 old_class_idx = the_class->enclosing_method_class_index();
4009 u2 old_method_idx = the_class->enclosing_method_method_index();
4010 the_class->set_enclosing_method_indices(
4011 scratch_class->enclosing_method_class_index(),
4012 scratch_class->enclosing_method_method_index());
4013 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx);
4014
4015 // Replace fingerprint data
4016 the_class->set_has_passed_fingerprint_check(scratch_class->has_passed_fingerprint_check());
4017 the_class->store_fingerprint(scratch_class->get_stored_fingerprint());
4018
4019 the_class->set_has_been_redefined();
4020
4021 if (!the_class->should_be_initialized()) {
4022 // Class was already initialized, so AOT has only seen the original version.
4023 // We need to let AOT look at it again.
4024 AOTLoader::load_for_klass(the_class, THREAD);
4025 }
4026
4027 // keep track of previous versions of this class
4028 the_class->add_previous_version(scratch_class, emcp_method_count);
4029
4030 _timer_rsc_phase1.stop();
4031 if (log_is_enabled(Info, redefine, class, timer)) {
4032 _timer_rsc_phase2.start();
4033 }
4034
4035 // Adjust constantpool caches and vtables for all classes
4036 // that reference methods of the evolved class.
4037 AdjustCpoolCacheAndVtable adjust_cpool_cache_and_vtable(THREAD);
4038 ClassLoaderDataGraph::classes_do(&adjust_cpool_cache_and_vtable);
4039
4040 // JSR-292 support
4041 MemberNameTable* mnt = the_class->member_names();
4042 if (mnt != NULL) {
4043 bool trace_name_printed = false;
4044 mnt->adjust_method_entries(the_class(), &trace_name_printed);
4045 }
4046
4047 if (the_class->oop_map_cache() != NULL) {
4048 // Flush references to any obsolete methods from the oop map cache
4049 // so that obsolete methods are not pinned.
4050 the_class->oop_map_cache()->flush_obsolete_entries();
4051 }
4052
4053 {
4054 ResourceMark rm(THREAD);
4055 // increment the classRedefinedCount field in the_class and in any
4056 // direct and indirect subclasses of the_class
4057 increment_class_counter((InstanceKlass *)the_class(), THREAD);
4058 log_info(redefine, class, load)
4059 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)",
4060 the_class->external_name(), java_lang_Class::classRedefinedCount(the_class->java_mirror()), os::available_memory() >> 10);
4061 Events::log_redefinition(THREAD, "redefined class name=%s, count=%d",
4062 the_class->external_name(),
4063 java_lang_Class::classRedefinedCount(the_class->java_mirror()));
4064
4065 }
4066 _timer_rsc_phase2.stop();
4067 } // end redefine_single_class()
4068
4069
4070 // Increment the classRedefinedCount field in the specific InstanceKlass
4071 // and in all direct and indirect subclasses.
4072 void VM_RedefineClasses::increment_class_counter(InstanceKlass *ik, TRAPS) {
4073 oop class_mirror = ik->java_mirror();
4074 Klass* class_oop = java_lang_Class::as_Klass(class_mirror);
4075 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
4076 java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
4077
4078 if (class_oop != _the_class_oop) {
4079 // _the_class_oop count is printed at end of redefine_single_class()
4080 log_debug(redefine, class, subclass)("updated count in subclass=%s to %d", ik->external_name(), new_count);
4081 }
4082
4083 for (Klass *subk = ik->subklass(); subk != NULL;
4084 subk = subk->next_sibling()) {
4085 if (subk->is_instance_klass()) {
4086 // Only update instanceKlasses
4087 InstanceKlass *subik = InstanceKlass::cast(subk);
4088 // recursively do subclasses of the current subclass
4089 increment_class_counter(subik, THREAD);
4090 }
4091 }
4092 }
4093
4094 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) {
4095 bool no_old_methods = true; // be optimistic
4096
4097 // Both array and instance classes have vtables.
4098 // a vtable should never contain old or obsolete methods
4099 ResourceMark rm(_thread);
4100 if (k->vtable_length() > 0 &&
4101 !k->vtable()->check_no_old_or_obsolete_entries()) {
4102 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4103 log_trace(redefine, class, obsolete, metadata)
4104 ("klassVtable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4105 k->signature_name());
4106 k->vtable()->dump_vtable();
4107 }
4108 no_old_methods = false;
4109 }
4110
4111 if (k->is_instance_klass()) {
4112 HandleMark hm(_thread);
4113 InstanceKlass *ik = InstanceKlass::cast(k);
4114
4115 // an itable should never contain old or obsolete methods
4116 if (ik->itable_length() > 0 &&
4117 !ik->itable()->check_no_old_or_obsolete_entries()) {
4118 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4119 log_trace(redefine, class, obsolete, metadata)
4120 ("klassItable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4121 ik->signature_name());
4122 ik->itable()->dump_itable();
4123 }
4124 no_old_methods = false;
4125 }
4126
4127 // the constant pool cache should never contain non-deleted old or obsolete methods
4128 if (ik->constants() != NULL &&
4129 ik->constants()->cache() != NULL &&
4130 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) {
4131 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4132 log_trace(redefine, class, obsolete, metadata)
4133 ("cp-cache::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4134 ik->signature_name());
4135 ik->constants()->cache()->dump_cache();
4136 }
4137 no_old_methods = false;
4138 }
4139 }
4140
4141 // print and fail guarantee if old methods are found.
4142 if (!no_old_methods) {
4143 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4144 dump_methods();
4145 } else {
4146 log_trace(redefine, class)("Use the '-Xlog:redefine+class*:' option "
4147 "to see more info about the following guarantee() failure.");
4148 }
4149 guarantee(false, "OLD and/or OBSOLETE method(s) found");
4150 }
4151 }
4152
4153
4154 void VM_RedefineClasses::dump_methods() {
4155 int j;
4156 log_trace(redefine, class, dump)("_old_methods --");
4157 for (j = 0; j < _old_methods->length(); ++j) {
4158 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4159 Method* m = _old_methods->at(j);
4160 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4161 m->access_flags().print_on(&log_stream);
4162 log_stream.print(" -- ");
4163 m->print_name(&log_stream);
4164 log_stream.cr();
4165 }
4166 log_trace(redefine, class, dump)("_new_methods --");
4167 for (j = 0; j < _new_methods->length(); ++j) {
4168 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4169 Method* m = _new_methods->at(j);
4170 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4171 m->access_flags().print_on(&log_stream);
4172 log_stream.print(" -- ");
4173 m->print_name(&log_stream);
4174 log_stream.cr();
4175 }
4176 log_trace(redefine, class, dump)("_matching_methods --");
4177 for (j = 0; j < _matching_methods_length; ++j) {
4178 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4179 Method* m = _matching_old_methods[j];
4180 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4181 m->access_flags().print_on(&log_stream);
4182 log_stream.print(" -- ");
4183 m->print_name();
4184 log_stream.cr();
4185
4186 m = _matching_new_methods[j];
4187 log_stream.print(" (%5d) ", m->vtable_index());
4188 m->access_flags().print_on(&log_stream);
4189 log_stream.cr();
4190 }
4191 log_trace(redefine, class, dump)("_deleted_methods --");
4192 for (j = 0; j < _deleted_methods_length; ++j) {
4193 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4194 Method* m = _deleted_methods[j];
4195 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4196 m->access_flags().print_on(&log_stream);
4197 log_stream.print(" -- ");
4198 m->print_name(&log_stream);
4199 log_stream.cr();
4200 }
4201 log_trace(redefine, class, dump)("_added_methods --");
4202 for (j = 0; j < _added_methods_length; ++j) {
4203 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4204 Method* m = _added_methods[j];
4205 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4206 m->access_flags().print_on(&log_stream);
4207 log_stream.print(" -- ");
4208 m->print_name(&log_stream);
4209 log_stream.cr();
4210 }
4211 }
4212
4213 void VM_RedefineClasses::print_on_error(outputStream* st) const {
4214 VM_Operation::print_on_error(st);
4215 if (_the_class_oop != NULL) {
4216 ResourceMark rm;
4217 st->print_cr(", redefining class %s", _the_class_oop->external_name());
4218 }
4219 }