1 /*
2 * Copyright (c) 2003, 2017, 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 = 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 to null for error printing.
231 _the_class = 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 InstanceKlass* the_class,
661 InstanceKlass* 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 = (InstanceKlass**)
997 os::malloc(sizeof(InstanceKlass*) * _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 InstanceKlass* the_class = 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 InstanceKlass* scratch_class = SystemDictionary::parse_stream(
1038 the_class_sym,
1039 the_class_loader,
1040 protection_domain,
1041 &st,
1042 THREAD);
1043 // Clear class_being_redefined just to be sure.
1044 state->clear_class_being_redefined();
1045
1046 // TODO: if this is retransform, and nothing changed we can skip it
1047
1048 // Need to clean up allocated InstanceKlass if there's an error so assign
1049 // the result here. Caller deallocates all the scratch classes in case of
1050 // an error.
1051 _scratch_classes[i] = scratch_class;
1052
1053 if (HAS_PENDING_EXCEPTION) {
1054 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1055 log_info(redefine, class, load, exceptions)("parse_stream exception: '%s'", ex_name->as_C_string());
1056 CLEAR_PENDING_EXCEPTION;
1057
1058 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) {
1059 return JVMTI_ERROR_UNSUPPORTED_VERSION;
1060 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) {
1061 return JVMTI_ERROR_INVALID_CLASS_FORMAT;
1062 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) {
1063 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION;
1064 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
1065 // The message will be "XXX (wrong name: YYY)"
1066 return JVMTI_ERROR_NAMES_DONT_MATCH;
1067 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1068 return JVMTI_ERROR_OUT_OF_MEMORY;
1069 } else { // Just in case more exceptions can be thrown..
1070 return JVMTI_ERROR_FAILS_VERIFICATION;
1071 }
1072 }
1073
1074 // Ensure class is linked before redefine
1075 if (!the_class->is_linked()) {
1076 the_class->link_class(THREAD);
1077 if (HAS_PENDING_EXCEPTION) {
1078 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1079 log_info(redefine, class, load, exceptions)("link_class exception: '%s'", ex_name->as_C_string());
1080 CLEAR_PENDING_EXCEPTION;
1081 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1082 return JVMTI_ERROR_OUT_OF_MEMORY;
1083 } else {
1084 return JVMTI_ERROR_INTERNAL;
1085 }
1086 }
1087 }
1088
1089 // Do the validity checks in compare_and_normalize_class_versions()
1090 // before verifying the byte codes. By doing these checks first, we
1091 // limit the number of functions that require redirection from
1092 // the_class to scratch_class. In particular, we don't have to
1093 // modify JNI GetSuperclass() and thus won't change its performance.
1094 jvmtiError res = compare_and_normalize_class_versions(the_class,
1095 scratch_class);
1096 if (res != JVMTI_ERROR_NONE) {
1097 return res;
1098 }
1099
1100 // verify what the caller passed us
1101 {
1102 // The bug 6214132 caused the verification to fail.
1103 // Information about the_class and scratch_class is temporarily
1104 // recorded into jvmtiThreadState. This data is used to redirect
1105 // the_class to scratch_class in the JVM_* functions called by the
1106 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed
1107 // description.
1108 RedefineVerifyMark rvm(the_class, scratch_class, state);
1109 Verifier::verify(
1110 scratch_class, Verifier::ThrowException, true, THREAD);
1111 }
1112
1113 if (HAS_PENDING_EXCEPTION) {
1114 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1115 log_info(redefine, class, load, exceptions)("verify_byte_codes exception: '%s'", ex_name->as_C_string());
1116 CLEAR_PENDING_EXCEPTION;
1117 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1118 return JVMTI_ERROR_OUT_OF_MEMORY;
1119 } else {
1120 // tell the caller the bytecodes are bad
1121 return JVMTI_ERROR_FAILS_VERIFICATION;
1122 }
1123 }
1124
1125 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD);
1126 if (HAS_PENDING_EXCEPTION) {
1127 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1128 log_info(redefine, class, load, exceptions)("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string());
1129 CLEAR_PENDING_EXCEPTION;
1130 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1131 return JVMTI_ERROR_OUT_OF_MEMORY;
1132 } else {
1133 return JVMTI_ERROR_INTERNAL;
1134 }
1135 }
1136
1137 if (VerifyMergedCPBytecodes) {
1138 // verify what we have done during constant pool merging
1139 {
1140 RedefineVerifyMark rvm(the_class, scratch_class, state);
1141 Verifier::verify(scratch_class, Verifier::ThrowException, true, THREAD);
1142 }
1143
1144 if (HAS_PENDING_EXCEPTION) {
1145 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1146 log_info(redefine, class, load, exceptions)
1147 ("verify_byte_codes post merge-CP exception: '%s'", ex_name->as_C_string());
1148 CLEAR_PENDING_EXCEPTION;
1149 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1150 return JVMTI_ERROR_OUT_OF_MEMORY;
1151 } else {
1152 // tell the caller that constant pool merging screwed up
1153 return JVMTI_ERROR_INTERNAL;
1154 }
1155 }
1156 }
1157
1158 Rewriter::rewrite(scratch_class, THREAD);
1159 if (!HAS_PENDING_EXCEPTION) {
1160 scratch_class->link_methods(THREAD);
1161 }
1162 if (HAS_PENDING_EXCEPTION) {
1163 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1164 log_info(redefine, class, load, exceptions)
1165 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string());
1166 CLEAR_PENDING_EXCEPTION;
1167 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1168 return JVMTI_ERROR_OUT_OF_MEMORY;
1169 } else {
1170 return JVMTI_ERROR_INTERNAL;
1171 }
1172 }
1173
1174 log_debug(redefine, class, load)
1175 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)", the_class->external_name(), os::available_memory() >> 10);
1176 }
1177
1178 return JVMTI_ERROR_NONE;
1179 }
1180
1181
1182 // Map old_index to new_index as needed. scratch_cp is only needed
1183 // for log calls.
1184 void VM_RedefineClasses::map_index(const constantPoolHandle& scratch_cp,
1185 int old_index, int new_index) {
1186 if (find_new_index(old_index) != 0) {
1187 // old_index is already mapped
1188 return;
1189 }
1190
1191 if (old_index == new_index) {
1192 // no mapping is needed
1193 return;
1194 }
1195
1196 _index_map_p->at_put(old_index, new_index);
1197 _index_map_count++;
1198
1199 log_trace(redefine, class, constantpool)
1200 ("mapped tag %d at index %d to %d", scratch_cp->tag_at(old_index).value(), old_index, new_index);
1201 } // end map_index()
1202
1203
1204 // Map old_index to new_index as needed.
1205 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) {
1206 if (find_new_operand_index(old_index) != -1) {
1207 // old_index is already mapped
1208 return;
1209 }
1210
1211 if (old_index == new_index) {
1212 // no mapping is needed
1213 return;
1214 }
1215
1216 _operands_index_map_p->at_put(old_index, new_index);
1217 _operands_index_map_count++;
1218
1219 log_trace(redefine, class, constantpool)("mapped bootstrap specifier at index %d to %d", old_index, new_index);
1220 } // end map_index()
1221
1222
1223 // Merge old_cp and scratch_cp and return the results of the merge via
1224 // merge_cp_p. The number of entries in *merge_cp_p is returned via
1225 // merge_cp_length_p. The entries in old_cp occupy the same locations
1226 // in *merge_cp_p. Also creates a map of indices from entries in
1227 // scratch_cp to the corresponding entry in *merge_cp_p. Index map
1228 // entries are only created for entries in scratch_cp that occupy a
1229 // different location in *merged_cp_p.
1230 bool VM_RedefineClasses::merge_constant_pools(const constantPoolHandle& old_cp,
1231 const constantPoolHandle& scratch_cp, constantPoolHandle *merge_cp_p,
1232 int *merge_cp_length_p, TRAPS) {
1233
1234 if (merge_cp_p == NULL) {
1235 assert(false, "caller must provide scratch constantPool");
1236 return false; // robustness
1237 }
1238 if (merge_cp_length_p == NULL) {
1239 assert(false, "caller must provide scratch CP length");
1240 return false; // robustness
1241 }
1242 // Worst case we need old_cp->length() + scratch_cp()->length(),
1243 // but the caller might be smart so make sure we have at least
1244 // the minimum.
1245 if ((*merge_cp_p)->length() < old_cp->length()) {
1246 assert(false, "merge area too small");
1247 return false; // robustness
1248 }
1249
1250 log_info(redefine, class, constantpool)("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(), scratch_cp->length());
1251
1252 {
1253 // Pass 0:
1254 // The old_cp is copied to *merge_cp_p; this means that any code
1255 // using old_cp does not have to change. This work looks like a
1256 // perfect fit for ConstantPool*::copy_cp_to(), but we need to
1257 // handle one special case:
1258 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass
1259 // This will make verification happy.
1260
1261 int old_i; // index into old_cp
1262
1263 // index zero (0) is not used in constantPools
1264 for (old_i = 1; old_i < old_cp->length(); old_i++) {
1265 // leave debugging crumb
1266 jbyte old_tag = old_cp->tag_at(old_i).value();
1267 switch (old_tag) {
1268 case JVM_CONSTANT_Class:
1269 case JVM_CONSTANT_UnresolvedClass:
1270 // revert the copy to JVM_CONSTANT_UnresolvedClass
1271 // May be resolving while calling this so do the same for
1272 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition)
1273 (*merge_cp_p)->unresolved_klass_at_put(old_i,
1274 old_cp->klass_name_at(old_i));
1275 break;
1276
1277 case JVM_CONSTANT_Double:
1278 case JVM_CONSTANT_Long:
1279 // just copy the entry to *merge_cp_p, but double and long take
1280 // two constant pool entries
1281 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1282 old_i++;
1283 break;
1284
1285 default:
1286 // just copy the entry to *merge_cp_p
1287 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1288 break;
1289 }
1290 } // end for each old_cp entry
1291
1292 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_0);
1293 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_0);
1294
1295 // We don't need to sanity check that *merge_cp_length_p is within
1296 // *merge_cp_p bounds since we have the minimum on-entry check above.
1297 (*merge_cp_length_p) = old_i;
1298 }
1299
1300 // merge_cp_len should be the same as old_cp->length() at this point
1301 // so this trace message is really a "warm-and-breathing" message.
1302 log_debug(redefine, class, constantpool)("after pass 0: merge_cp_len=%d", *merge_cp_length_p);
1303
1304 int scratch_i; // index into scratch_cp
1305 {
1306 // Pass 1a:
1307 // Compare scratch_cp entries to the old_cp entries that we have
1308 // already copied to *merge_cp_p. In this pass, we are eliminating
1309 // exact duplicates (matching entry at same index) so we only
1310 // compare entries in the common indice range.
1311 int increment = 1;
1312 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length());
1313 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) {
1314 switch (scratch_cp->tag_at(scratch_i).value()) {
1315 case JVM_CONSTANT_Double:
1316 case JVM_CONSTANT_Long:
1317 // double and long take two constant pool entries
1318 increment = 2;
1319 break;
1320
1321 default:
1322 increment = 1;
1323 break;
1324 }
1325
1326 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p,
1327 scratch_i, CHECK_0);
1328 if (match) {
1329 // found a match at the same index so nothing more to do
1330 continue;
1331 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i,
1332 *merge_cp_p, scratch_i)) {
1333 // The mismatch in compare_entry_to() above is because of a
1334 // resolved versus unresolved class entry at the same index
1335 // with the same string value. Since Pass 0 reverted any
1336 // class entries to unresolved class entries in *merge_cp_p,
1337 // we go with the unresolved class entry.
1338 continue;
1339 }
1340
1341 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p,
1342 CHECK_0);
1343 if (found_i != 0) {
1344 guarantee(found_i != scratch_i,
1345 "compare_entry_to() and find_matching_entry() do not agree");
1346
1347 // Found a matching entry somewhere else in *merge_cp_p so
1348 // just need a mapping entry.
1349 map_index(scratch_cp, scratch_i, found_i);
1350 continue;
1351 }
1352
1353 // The find_matching_entry() call above could fail to find a match
1354 // due to a resolved versus unresolved class or string entry situation
1355 // like we solved above with the is_unresolved_*_mismatch() calls.
1356 // However, we would have to call is_unresolved_*_mismatch() over
1357 // all of *merge_cp_p (potentially) and that doesn't seem to be
1358 // worth the time.
1359
1360 // No match found so we have to append this entry and any unique
1361 // referenced entries to *merge_cp_p.
1362 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1363 CHECK_0);
1364 }
1365 }
1366
1367 log_debug(redefine, class, constantpool)
1368 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1369 *merge_cp_length_p, scratch_i, _index_map_count);
1370
1371 if (scratch_i < scratch_cp->length()) {
1372 // Pass 1b:
1373 // old_cp is smaller than scratch_cp so there are entries in
1374 // scratch_cp that we have not yet processed. We take care of
1375 // those now.
1376 int increment = 1;
1377 for (; scratch_i < scratch_cp->length(); scratch_i += increment) {
1378 switch (scratch_cp->tag_at(scratch_i).value()) {
1379 case JVM_CONSTANT_Double:
1380 case JVM_CONSTANT_Long:
1381 // double and long take two constant pool entries
1382 increment = 2;
1383 break;
1384
1385 default:
1386 increment = 1;
1387 break;
1388 }
1389
1390 int found_i =
1391 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0);
1392 if (found_i != 0) {
1393 // Found a matching entry somewhere else in *merge_cp_p so
1394 // just need a mapping entry.
1395 map_index(scratch_cp, scratch_i, found_i);
1396 continue;
1397 }
1398
1399 // No match found so we have to append this entry and any unique
1400 // referenced entries to *merge_cp_p.
1401 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1402 CHECK_0);
1403 }
1404
1405 log_debug(redefine, class, constantpool)
1406 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1407 *merge_cp_length_p, scratch_i, _index_map_count);
1408 }
1409 finalize_operands_merge(*merge_cp_p, THREAD);
1410
1411 return true;
1412 } // end merge_constant_pools()
1413
1414
1415 // Scoped object to clean up the constant pool(s) created for merging
1416 class MergeCPCleaner {
1417 ClassLoaderData* _loader_data;
1418 ConstantPool* _cp;
1419 ConstantPool* _scratch_cp;
1420 public:
1421 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) :
1422 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {}
1423 ~MergeCPCleaner() {
1424 _loader_data->add_to_deallocate_list(_cp);
1425 if (_scratch_cp != NULL) {
1426 _loader_data->add_to_deallocate_list(_scratch_cp);
1427 }
1428 }
1429 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; }
1430 };
1431
1432 // Merge constant pools between the_class and scratch_class and
1433 // potentially rewrite bytecodes in scratch_class to use the merged
1434 // constant pool.
1435 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite(
1436 InstanceKlass* the_class, InstanceKlass* scratch_class,
1437 TRAPS) {
1438 // worst case merged constant pool length is old and new combined
1439 int merge_cp_length = the_class->constants()->length()
1440 + scratch_class->constants()->length();
1441
1442 // Constant pools are not easily reused so we allocate a new one
1443 // each time.
1444 // merge_cp is created unsafe for concurrent GC processing. It
1445 // should be marked safe before discarding it. Even though
1446 // garbage, if it crosses a card boundary, it may be scanned
1447 // in order to find the start of the first complete object on the card.
1448 ClassLoaderData* loader_data = the_class->class_loader_data();
1449 ConstantPool* merge_cp_oop =
1450 ConstantPool::allocate(loader_data,
1451 merge_cp_length,
1452 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1453 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop);
1454
1455 HandleMark hm(THREAD); // make sure handles are cleared before
1456 // MergeCPCleaner clears out merge_cp_oop
1457 constantPoolHandle merge_cp(THREAD, merge_cp_oop);
1458
1459 // Get constants() from the old class because it could have been rewritten
1460 // while we were at a safepoint allocating a new constant pool.
1461 constantPoolHandle old_cp(THREAD, the_class->constants());
1462 constantPoolHandle scratch_cp(THREAD, scratch_class->constants());
1463
1464 // If the length changed, the class was redefined out from under us. Return
1465 // an error.
1466 if (merge_cp_length != the_class->constants()->length()
1467 + scratch_class->constants()->length()) {
1468 return JVMTI_ERROR_INTERNAL;
1469 }
1470
1471 // Update the version number of the constant pools (may keep scratch_cp)
1472 merge_cp->increment_and_save_version(old_cp->version());
1473 scratch_cp->increment_and_save_version(old_cp->version());
1474
1475 ResourceMark rm(THREAD);
1476 _index_map_count = 0;
1477 _index_map_p = new intArray(scratch_cp->length(), scratch_cp->length(), -1);
1478
1479 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands());
1480 _operands_index_map_count = 0;
1481 int operands_index_map_len = ConstantPool::operand_array_length(scratch_cp->operands());
1482 _operands_index_map_p = new intArray(operands_index_map_len, operands_index_map_len, -1);
1483
1484 // reference to the cp holder is needed for copy_operands()
1485 merge_cp->set_pool_holder(scratch_class);
1486 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp,
1487 &merge_cp_length, THREAD);
1488 merge_cp->set_pool_holder(NULL);
1489
1490 if (!result) {
1491 // The merge can fail due to memory allocation failure or due
1492 // to robustness checks.
1493 return JVMTI_ERROR_INTERNAL;
1494 }
1495
1496 log_info(redefine, class, constantpool)("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count);
1497
1498 if (_index_map_count == 0) {
1499 // there is nothing to map between the new and merged constant pools
1500
1501 if (old_cp->length() == scratch_cp->length()) {
1502 // The old and new constant pools are the same length and the
1503 // index map is empty. This means that the three constant pools
1504 // are equivalent (but not the same). Unfortunately, the new
1505 // constant pool has not gone through link resolution nor have
1506 // the new class bytecodes gone through constant pool cache
1507 // rewriting so we can't use the old constant pool with the new
1508 // class.
1509
1510 // toss the merged constant pool at return
1511 } else if (old_cp->length() < scratch_cp->length()) {
1512 // The old constant pool has fewer entries than the new constant
1513 // pool and the index map is empty. This means the new constant
1514 // pool is a superset of the old constant pool. However, the old
1515 // class bytecodes have already gone through constant pool cache
1516 // rewriting so we can't use the new constant pool with the old
1517 // class.
1518
1519 // toss the merged constant pool at return
1520 } else {
1521 // The old constant pool has more entries than the new constant
1522 // pool and the index map is empty. This means that both the old
1523 // and merged constant pools are supersets of the new constant
1524 // pool.
1525
1526 // Replace the new constant pool with a shrunken copy of the
1527 // merged constant pool
1528 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1529 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1530 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1531 // It can't be cleaned up while there are handles to it.
1532 cp_cleaner.add_scratch_cp(scratch_cp());
1533 }
1534 } else {
1535 if (log_is_enabled(Trace, redefine, class, constantpool)) {
1536 // don't want to loop unless we are tracing
1537 int count = 0;
1538 for (int i = 1; i < _index_map_p->length(); i++) {
1539 int value = _index_map_p->at(i);
1540
1541 if (value != -1) {
1542 log_trace(redefine, class, constantpool)("index_map[%d]: old=%d new=%d", count, i, value);
1543 count++;
1544 }
1545 }
1546 }
1547
1548 // We have entries mapped between the new and merged constant pools
1549 // so we have to rewrite some constant pool references.
1550 if (!rewrite_cp_refs(scratch_class, THREAD)) {
1551 return JVMTI_ERROR_INTERNAL;
1552 }
1553
1554 // Replace the new constant pool with a shrunken copy of the
1555 // merged constant pool so now the rewritten bytecodes have
1556 // valid references; the previous new constant pool will get
1557 // GCed.
1558 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1559 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1560 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1561 // It can't be cleaned up while there are handles to it.
1562 cp_cleaner.add_scratch_cp(scratch_cp());
1563 }
1564
1565 return JVMTI_ERROR_NONE;
1566 } // end merge_cp_and_rewrite()
1567
1568
1569 // Rewrite constant pool references in klass scratch_class.
1570 bool VM_RedefineClasses::rewrite_cp_refs(InstanceKlass* scratch_class,
1571 TRAPS) {
1572
1573 // rewrite constant pool references in the methods:
1574 if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) {
1575 // propagate failure back to caller
1576 return false;
1577 }
1578
1579 // rewrite constant pool references in the class_annotations:
1580 if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) {
1581 // propagate failure back to caller
1582 return false;
1583 }
1584
1585 // rewrite constant pool references in the fields_annotations:
1586 if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) {
1587 // propagate failure back to caller
1588 return false;
1589 }
1590
1591 // rewrite constant pool references in the methods_annotations:
1592 if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) {
1593 // propagate failure back to caller
1594 return false;
1595 }
1596
1597 // rewrite constant pool references in the methods_parameter_annotations:
1598 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class,
1599 THREAD)) {
1600 // propagate failure back to caller
1601 return false;
1602 }
1603
1604 // rewrite constant pool references in the methods_default_annotations:
1605 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class,
1606 THREAD)) {
1607 // propagate failure back to caller
1608 return false;
1609 }
1610
1611 // rewrite constant pool references in the class_type_annotations:
1612 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class, THREAD)) {
1613 // propagate failure back to caller
1614 return false;
1615 }
1616
1617 // rewrite constant pool references in the fields_type_annotations:
1618 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class, THREAD)) {
1619 // propagate failure back to caller
1620 return false;
1621 }
1622
1623 // rewrite constant pool references in the methods_type_annotations:
1624 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class, THREAD)) {
1625 // propagate failure back to caller
1626 return false;
1627 }
1628
1629 // There can be type annotations in the Code part of a method_info attribute.
1630 // These annotations are not accessible, even by reflection.
1631 // Currently they are not even parsed by the ClassFileParser.
1632 // If runtime access is added they will also need to be rewritten.
1633
1634 // rewrite source file name index:
1635 u2 source_file_name_idx = scratch_class->source_file_name_index();
1636 if (source_file_name_idx != 0) {
1637 u2 new_source_file_name_idx = find_new_index(source_file_name_idx);
1638 if (new_source_file_name_idx != 0) {
1639 scratch_class->set_source_file_name_index(new_source_file_name_idx);
1640 }
1641 }
1642
1643 // rewrite class generic signature index:
1644 u2 generic_signature_index = scratch_class->generic_signature_index();
1645 if (generic_signature_index != 0) {
1646 u2 new_generic_signature_index = find_new_index(generic_signature_index);
1647 if (new_generic_signature_index != 0) {
1648 scratch_class->set_generic_signature_index(new_generic_signature_index);
1649 }
1650 }
1651
1652 return true;
1653 } // end rewrite_cp_refs()
1654
1655 // Rewrite constant pool references in the methods.
1656 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(
1657 InstanceKlass* scratch_class, TRAPS) {
1658
1659 Array<Method*>* methods = scratch_class->methods();
1660
1661 if (methods == NULL || methods->length() == 0) {
1662 // no methods so nothing to do
1663 return true;
1664 }
1665
1666 // rewrite constant pool references in the methods:
1667 for (int i = methods->length() - 1; i >= 0; i--) {
1668 methodHandle method(THREAD, methods->at(i));
1669 methodHandle new_method;
1670 rewrite_cp_refs_in_method(method, &new_method, THREAD);
1671 if (!new_method.is_null()) {
1672 // the method has been replaced so save the new method version
1673 // even in the case of an exception. original method is on the
1674 // deallocation list.
1675 methods->at_put(i, new_method());
1676 }
1677 if (HAS_PENDING_EXCEPTION) {
1678 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1679 log_info(redefine, class, load, exceptions)("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string());
1680 // Need to clear pending exception here as the super caller sets
1681 // the JVMTI_ERROR_INTERNAL if the returned value is false.
1682 CLEAR_PENDING_EXCEPTION;
1683 return false;
1684 }
1685 }
1686
1687 return true;
1688 }
1689
1690
1691 // Rewrite constant pool references in the specific method. This code
1692 // was adapted from Rewriter::rewrite_method().
1693 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method,
1694 methodHandle *new_method_p, TRAPS) {
1695
1696 *new_method_p = methodHandle(); // default is no new method
1697
1698 // We cache a pointer to the bytecodes here in code_base. If GC
1699 // moves the Method*, then the bytecodes will also move which
1700 // will likely cause a crash. We create a NoSafepointVerifier
1701 // object to detect whether we pass a possible safepoint in this
1702 // code block.
1703 NoSafepointVerifier nsv;
1704
1705 // Bytecodes and their length
1706 address code_base = method->code_base();
1707 int code_length = method->code_size();
1708
1709 int bc_length;
1710 for (int bci = 0; bci < code_length; bci += bc_length) {
1711 address bcp = code_base + bci;
1712 Bytecodes::Code c = (Bytecodes::Code)(*bcp);
1713
1714 bc_length = Bytecodes::length_for(c);
1715 if (bc_length == 0) {
1716 // More complicated bytecodes report a length of zero so
1717 // we have to try again a slightly different way.
1718 bc_length = Bytecodes::length_at(method(), bcp);
1719 }
1720
1721 assert(bc_length != 0, "impossible bytecode length");
1722
1723 switch (c) {
1724 case Bytecodes::_ldc:
1725 {
1726 int cp_index = *(bcp + 1);
1727 int new_index = find_new_index(cp_index);
1728
1729 if (StressLdcRewrite && new_index == 0) {
1730 // If we are stressing ldc -> ldc_w rewriting, then we
1731 // always need a new_index value.
1732 new_index = cp_index;
1733 }
1734 if (new_index != 0) {
1735 // the original index is mapped so we have more work to do
1736 if (!StressLdcRewrite && new_index <= max_jubyte) {
1737 // The new value can still use ldc instead of ldc_w
1738 // unless we are trying to stress ldc -> ldc_w rewriting
1739 log_trace(redefine, class, constantpool)
1740 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index);
1741 *(bcp + 1) = new_index;
1742 } else {
1743 log_trace(redefine, class, constantpool)
1744 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index);
1745 // the new value needs ldc_w instead of ldc
1746 u_char inst_buffer[4]; // max instruction size is 4 bytes
1747 bcp = (address)inst_buffer;
1748 // construct new instruction sequence
1749 *bcp = Bytecodes::_ldc_w;
1750 bcp++;
1751 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w.
1752 // See comment below for difference between put_Java_u2()
1753 // and put_native_u2().
1754 Bytes::put_Java_u2(bcp, new_index);
1755
1756 Relocator rc(method, NULL /* no RelocatorListener needed */);
1757 methodHandle m;
1758 {
1759 PauseNoSafepointVerifier pnsv(&nsv);
1760
1761 // ldc is 2 bytes and ldc_w is 3 bytes
1762 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK);
1763 }
1764
1765 // return the new method so that the caller can update
1766 // the containing class
1767 *new_method_p = method = m;
1768 // switch our bytecode processing loop from the old method
1769 // to the new method
1770 code_base = method->code_base();
1771 code_length = method->code_size();
1772 bcp = code_base + bci;
1773 c = (Bytecodes::Code)(*bcp);
1774 bc_length = Bytecodes::length_for(c);
1775 assert(bc_length != 0, "sanity check");
1776 } // end we need ldc_w instead of ldc
1777 } // end if there is a mapped index
1778 } break;
1779
1780 // these bytecodes have a two-byte constant pool index
1781 case Bytecodes::_anewarray : // fall through
1782 case Bytecodes::_checkcast : // fall through
1783 case Bytecodes::_getfield : // fall through
1784 case Bytecodes::_getstatic : // fall through
1785 case Bytecodes::_instanceof : // fall through
1786 case Bytecodes::_invokedynamic : // fall through
1787 case Bytecodes::_invokeinterface: // fall through
1788 case Bytecodes::_invokespecial : // fall through
1789 case Bytecodes::_invokestatic : // fall through
1790 case Bytecodes::_invokevirtual : // fall through
1791 case Bytecodes::_ldc_w : // fall through
1792 case Bytecodes::_ldc2_w : // fall through
1793 case Bytecodes::_multianewarray : // fall through
1794 case Bytecodes::_new : // fall through
1795 case Bytecodes::_putfield : // fall through
1796 case Bytecodes::_putstatic :
1797 {
1798 address p = bcp + 1;
1799 int cp_index = Bytes::get_Java_u2(p);
1800 int new_index = find_new_index(cp_index);
1801 if (new_index != 0) {
1802 // the original index is mapped so update w/ new value
1803 log_trace(redefine, class, constantpool)
1804 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),p2i(bcp), cp_index, new_index);
1805 // Rewriter::rewrite_method() uses put_native_u2() in this
1806 // situation because it is reusing the constant pool index
1807 // location for a native index into the ConstantPoolCache.
1808 // Since we are updating the constant pool index prior to
1809 // verification and ConstantPoolCache initialization, we
1810 // need to keep the new index in Java byte order.
1811 Bytes::put_Java_u2(p, new_index);
1812 }
1813 } break;
1814 }
1815 } // end for each bytecode
1816
1817 // We also need to rewrite the parameter name indexes, if there is
1818 // method parameter data present
1819 if(method->has_method_parameters()) {
1820 const int len = method->method_parameters_length();
1821 MethodParametersElement* elem = method->method_parameters_start();
1822
1823 for (int i = 0; i < len; i++) {
1824 const u2 cp_index = elem[i].name_cp_index;
1825 const u2 new_cp_index = find_new_index(cp_index);
1826 if (new_cp_index != 0) {
1827 elem[i].name_cp_index = new_cp_index;
1828 }
1829 }
1830 }
1831 } // end rewrite_cp_refs_in_method()
1832
1833
1834 // Rewrite constant pool references in the class_annotations field.
1835 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(
1836 InstanceKlass* scratch_class, TRAPS) {
1837
1838 AnnotationArray* class_annotations = scratch_class->class_annotations();
1839 if (class_annotations == NULL || class_annotations->length() == 0) {
1840 // no class_annotations so nothing to do
1841 return true;
1842 }
1843
1844 log_debug(redefine, class, annotation)("class_annotations length=%d", class_annotations->length());
1845
1846 int byte_i = 0; // byte index into class_annotations
1847 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i,
1848 THREAD);
1849 }
1850
1851
1852 // Rewrite constant pool references in an annotations typeArray. This
1853 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute
1854 // that is described in section 4.8.15 of the 2nd-edition of the VM spec:
1855 //
1856 // annotations_typeArray {
1857 // u2 num_annotations;
1858 // annotation annotations[num_annotations];
1859 // }
1860 //
1861 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray(
1862 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1863
1864 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1865 // not enough room for num_annotations field
1866 log_debug(redefine, class, annotation)("length() is too small for num_annotations field");
1867 return false;
1868 }
1869
1870 u2 num_annotations = Bytes::get_Java_u2((address)
1871 annotations_typeArray->adr_at(byte_i_ref));
1872 byte_i_ref += 2;
1873
1874 log_debug(redefine, class, annotation)("num_annotations=%d", num_annotations);
1875
1876 int calc_num_annotations = 0;
1877 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
1878 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
1879 byte_i_ref, THREAD)) {
1880 log_debug(redefine, class, annotation)("bad annotation_struct at %d", calc_num_annotations);
1881 // propagate failure back to caller
1882 return false;
1883 }
1884 }
1885 assert(num_annotations == calc_num_annotations, "sanity check");
1886
1887 return true;
1888 } // end rewrite_cp_refs_in_annotations_typeArray()
1889
1890
1891 // Rewrite constant pool references in the annotation struct portion of
1892 // an annotations_typeArray. This "structure" is from section 4.8.15 of
1893 // the 2nd-edition of the VM spec:
1894 //
1895 // struct annotation {
1896 // u2 type_index;
1897 // u2 num_element_value_pairs;
1898 // {
1899 // u2 element_name_index;
1900 // element_value value;
1901 // } element_value_pairs[num_element_value_pairs];
1902 // }
1903 //
1904 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct(
1905 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1906 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) {
1907 // not enough room for smallest annotation_struct
1908 log_debug(redefine, class, annotation)("length() is too small for annotation_struct");
1909 return false;
1910 }
1911
1912 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray,
1913 byte_i_ref, "type_index", THREAD);
1914
1915 u2 num_element_value_pairs = Bytes::get_Java_u2((address)
1916 annotations_typeArray->adr_at(byte_i_ref));
1917 byte_i_ref += 2;
1918
1919 log_debug(redefine, class, annotation)
1920 ("type_index=%d num_element_value_pairs=%d", type_index, num_element_value_pairs);
1921
1922 int calc_num_element_value_pairs = 0;
1923 for (; calc_num_element_value_pairs < num_element_value_pairs;
1924 calc_num_element_value_pairs++) {
1925 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1926 // not enough room for another element_name_index, let alone
1927 // the rest of another component
1928 log_debug(redefine, class, annotation)("length() is too small for element_name_index");
1929 return false;
1930 }
1931
1932 u2 element_name_index = rewrite_cp_ref_in_annotation_data(
1933 annotations_typeArray, byte_i_ref,
1934 "element_name_index", THREAD);
1935
1936 log_debug(redefine, class, annotation)("element_name_index=%d", element_name_index);
1937
1938 if (!rewrite_cp_refs_in_element_value(annotations_typeArray,
1939 byte_i_ref, THREAD)) {
1940 log_debug(redefine, class, annotation)("bad element_value at %d", calc_num_element_value_pairs);
1941 // propagate failure back to caller
1942 return false;
1943 }
1944 } // end for each component
1945 assert(num_element_value_pairs == calc_num_element_value_pairs,
1946 "sanity check");
1947
1948 return true;
1949 } // end rewrite_cp_refs_in_annotation_struct()
1950
1951
1952 // Rewrite a constant pool reference at the current position in
1953 // annotations_typeArray if needed. Returns the original constant
1954 // pool reference if a rewrite was not needed or the new constant
1955 // pool reference if a rewrite was needed.
1956 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data(
1957 AnnotationArray* annotations_typeArray, int &byte_i_ref,
1958 const char * trace_mesg, TRAPS) {
1959
1960 address cp_index_addr = (address)
1961 annotations_typeArray->adr_at(byte_i_ref);
1962 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr);
1963 u2 new_cp_index = find_new_index(old_cp_index);
1964 if (new_cp_index != 0) {
1965 log_debug(redefine, class, annotation)("mapped old %s=%d", trace_mesg, old_cp_index);
1966 Bytes::put_Java_u2(cp_index_addr, new_cp_index);
1967 old_cp_index = new_cp_index;
1968 }
1969 byte_i_ref += 2;
1970 return old_cp_index;
1971 }
1972
1973
1974 // Rewrite constant pool references in the element_value portion of an
1975 // annotations_typeArray. This "structure" is from section 4.8.15.1 of
1976 // the 2nd-edition of the VM spec:
1977 //
1978 // struct element_value {
1979 // u1 tag;
1980 // union {
1981 // u2 const_value_index;
1982 // {
1983 // u2 type_name_index;
1984 // u2 const_name_index;
1985 // } enum_const_value;
1986 // u2 class_info_index;
1987 // annotation annotation_value;
1988 // struct {
1989 // u2 num_values;
1990 // element_value values[num_values];
1991 // } array_value;
1992 // } value;
1993 // }
1994 //
1995 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value(
1996 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1997
1998 if ((byte_i_ref + 1) > annotations_typeArray->length()) {
1999 // not enough room for a tag let alone the rest of an element_value
2000 log_debug(redefine, class, annotation)("length() is too small for a tag");
2001 return false;
2002 }
2003
2004 u1 tag = annotations_typeArray->at(byte_i_ref);
2005 byte_i_ref++;
2006 log_debug(redefine, class, annotation)("tag='%c'", tag);
2007
2008 switch (tag) {
2009 // These BaseType tag values are from Table 4.2 in VM spec:
2010 case 'B': // byte
2011 case 'C': // char
2012 case 'D': // double
2013 case 'F': // float
2014 case 'I': // int
2015 case 'J': // long
2016 case 'S': // short
2017 case 'Z': // boolean
2018
2019 // The remaining tag values are from Table 4.8 in the 2nd-edition of
2020 // the VM spec:
2021 case 's':
2022 {
2023 // For the above tag values (including the BaseType values),
2024 // value.const_value_index is right union field.
2025
2026 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2027 // not enough room for a const_value_index
2028 log_debug(redefine, class, annotation)("length() is too small for a const_value_index");
2029 return false;
2030 }
2031
2032 u2 const_value_index = rewrite_cp_ref_in_annotation_data(
2033 annotations_typeArray, byte_i_ref,
2034 "const_value_index", THREAD);
2035
2036 log_debug(redefine, class, annotation)("const_value_index=%d", const_value_index);
2037 } break;
2038
2039 case 'e':
2040 {
2041 // for the above tag value, value.enum_const_value is right union field
2042
2043 if ((byte_i_ref + 4) > annotations_typeArray->length()) {
2044 // not enough room for a enum_const_value
2045 log_debug(redefine, class, annotation)("length() is too small for a enum_const_value");
2046 return false;
2047 }
2048
2049 u2 type_name_index = rewrite_cp_ref_in_annotation_data(
2050 annotations_typeArray, byte_i_ref,
2051 "type_name_index", THREAD);
2052
2053 u2 const_name_index = rewrite_cp_ref_in_annotation_data(
2054 annotations_typeArray, byte_i_ref,
2055 "const_name_index", THREAD);
2056
2057 log_debug(redefine, class, annotation)
2058 ("type_name_index=%d const_name_index=%d", type_name_index, const_name_index);
2059 } break;
2060
2061 case 'c':
2062 {
2063 // for the above tag value, value.class_info_index is right union field
2064
2065 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2066 // not enough room for a class_info_index
2067 log_debug(redefine, class, annotation)("length() is too small for a class_info_index");
2068 return false;
2069 }
2070
2071 u2 class_info_index = rewrite_cp_ref_in_annotation_data(
2072 annotations_typeArray, byte_i_ref,
2073 "class_info_index", THREAD);
2074
2075 log_debug(redefine, class, annotation)("class_info_index=%d", class_info_index);
2076 } break;
2077
2078 case '@':
2079 // For the above tag value, value.attr_value is the right union
2080 // field. This is a nested annotation.
2081 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
2082 byte_i_ref, THREAD)) {
2083 // propagate failure back to caller
2084 return false;
2085 }
2086 break;
2087
2088 case '[':
2089 {
2090 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2091 // not enough room for a num_values field
2092 log_debug(redefine, class, annotation)("length() is too small for a num_values field");
2093 return false;
2094 }
2095
2096 // For the above tag value, value.array_value is the right union
2097 // field. This is an array of nested element_value.
2098 u2 num_values = Bytes::get_Java_u2((address)
2099 annotations_typeArray->adr_at(byte_i_ref));
2100 byte_i_ref += 2;
2101 log_debug(redefine, class, annotation)("num_values=%d", num_values);
2102
2103 int calc_num_values = 0;
2104 for (; calc_num_values < num_values; calc_num_values++) {
2105 if (!rewrite_cp_refs_in_element_value(
2106 annotations_typeArray, byte_i_ref, THREAD)) {
2107 log_debug(redefine, class, annotation)("bad nested element_value at %d", calc_num_values);
2108 // propagate failure back to caller
2109 return false;
2110 }
2111 }
2112 assert(num_values == calc_num_values, "sanity check");
2113 } break;
2114
2115 default:
2116 log_debug(redefine, class, annotation)("bad tag=0x%x", tag);
2117 return false;
2118 } // end decode tag field
2119
2120 return true;
2121 } // end rewrite_cp_refs_in_element_value()
2122
2123
2124 // Rewrite constant pool references in a fields_annotations field.
2125 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations(
2126 InstanceKlass* scratch_class, TRAPS) {
2127
2128 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations();
2129
2130 if (fields_annotations == NULL || fields_annotations->length() == 0) {
2131 // no fields_annotations so nothing to do
2132 return true;
2133 }
2134
2135 log_debug(redefine, class, annotation)("fields_annotations length=%d", fields_annotations->length());
2136
2137 for (int i = 0; i < fields_annotations->length(); i++) {
2138 AnnotationArray* field_annotations = fields_annotations->at(i);
2139 if (field_annotations == NULL || field_annotations->length() == 0) {
2140 // this field does not have any annotations so skip it
2141 continue;
2142 }
2143
2144 int byte_i = 0; // byte index into field_annotations
2145 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i,
2146 THREAD)) {
2147 log_debug(redefine, class, annotation)("bad field_annotations at %d", i);
2148 // propagate failure back to caller
2149 return false;
2150 }
2151 }
2152
2153 return true;
2154 } // end rewrite_cp_refs_in_fields_annotations()
2155
2156
2157 // Rewrite constant pool references in a methods_annotations field.
2158 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations(
2159 InstanceKlass* scratch_class, TRAPS) {
2160
2161 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2162 Method* m = scratch_class->methods()->at(i);
2163 AnnotationArray* method_annotations = m->constMethod()->method_annotations();
2164
2165 if (method_annotations == NULL || method_annotations->length() == 0) {
2166 // this method does not have any annotations so skip it
2167 continue;
2168 }
2169
2170 int byte_i = 0; // byte index into method_annotations
2171 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i,
2172 THREAD)) {
2173 log_debug(redefine, class, annotation)("bad method_annotations at %d", i);
2174 // propagate failure back to caller
2175 return false;
2176 }
2177 }
2178
2179 return true;
2180 } // end rewrite_cp_refs_in_methods_annotations()
2181
2182
2183 // Rewrite constant pool references in a methods_parameter_annotations
2184 // field. This "structure" is adapted from the
2185 // RuntimeVisibleParameterAnnotations_attribute described in section
2186 // 4.8.17 of the 2nd-edition of the VM spec:
2187 //
2188 // methods_parameter_annotations_typeArray {
2189 // u1 num_parameters;
2190 // {
2191 // u2 num_annotations;
2192 // annotation annotations[num_annotations];
2193 // } parameter_annotations[num_parameters];
2194 // }
2195 //
2196 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations(
2197 InstanceKlass* scratch_class, TRAPS) {
2198
2199 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2200 Method* m = scratch_class->methods()->at(i);
2201 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations();
2202 if (method_parameter_annotations == NULL
2203 || method_parameter_annotations->length() == 0) {
2204 // this method does not have any parameter annotations so skip it
2205 continue;
2206 }
2207
2208 if (method_parameter_annotations->length() < 1) {
2209 // not enough room for a num_parameters field
2210 log_debug(redefine, class, annotation)("length() is too small for a num_parameters field at %d", i);
2211 return false;
2212 }
2213
2214 int byte_i = 0; // byte index into method_parameter_annotations
2215
2216 u1 num_parameters = method_parameter_annotations->at(byte_i);
2217 byte_i++;
2218
2219 log_debug(redefine, class, annotation)("num_parameters=%d", num_parameters);
2220
2221 int calc_num_parameters = 0;
2222 for (; calc_num_parameters < num_parameters; calc_num_parameters++) {
2223 if (!rewrite_cp_refs_in_annotations_typeArray(
2224 method_parameter_annotations, byte_i, THREAD)) {
2225 log_debug(redefine, class, annotation)("bad method_parameter_annotations at %d", calc_num_parameters);
2226 // propagate failure back to caller
2227 return false;
2228 }
2229 }
2230 assert(num_parameters == calc_num_parameters, "sanity check");
2231 }
2232
2233 return true;
2234 } // end rewrite_cp_refs_in_methods_parameter_annotations()
2235
2236
2237 // Rewrite constant pool references in a methods_default_annotations
2238 // field. This "structure" is adapted from the AnnotationDefault_attribute
2239 // that is described in section 4.8.19 of the 2nd-edition of the VM spec:
2240 //
2241 // methods_default_annotations_typeArray {
2242 // element_value default_value;
2243 // }
2244 //
2245 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations(
2246 InstanceKlass* scratch_class, TRAPS) {
2247
2248 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2249 Method* m = scratch_class->methods()->at(i);
2250 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations();
2251 if (method_default_annotations == NULL
2252 || method_default_annotations->length() == 0) {
2253 // this method does not have any default annotations so skip it
2254 continue;
2255 }
2256
2257 int byte_i = 0; // byte index into method_default_annotations
2258
2259 if (!rewrite_cp_refs_in_element_value(
2260 method_default_annotations, byte_i, THREAD)) {
2261 log_debug(redefine, class, annotation)("bad default element_value at %d", i);
2262 // propagate failure back to caller
2263 return false;
2264 }
2265 }
2266
2267 return true;
2268 } // end rewrite_cp_refs_in_methods_default_annotations()
2269
2270
2271 // Rewrite constant pool references in a class_type_annotations field.
2272 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations(
2273 InstanceKlass* scratch_class, TRAPS) {
2274
2275 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations();
2276 if (class_type_annotations == NULL || class_type_annotations->length() == 0) {
2277 // no class_type_annotations so nothing to do
2278 return true;
2279 }
2280
2281 log_debug(redefine, class, annotation)("class_type_annotations length=%d", class_type_annotations->length());
2282
2283 int byte_i = 0; // byte index into class_type_annotations
2284 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations,
2285 byte_i, "ClassFile", THREAD);
2286 } // end rewrite_cp_refs_in_class_type_annotations()
2287
2288
2289 // Rewrite constant pool references in a fields_type_annotations field.
2290 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations(
2291 InstanceKlass* scratch_class, TRAPS) {
2292
2293 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations();
2294 if (fields_type_annotations == NULL || fields_type_annotations->length() == 0) {
2295 // no fields_type_annotations so nothing to do
2296 return true;
2297 }
2298
2299 log_debug(redefine, class, annotation)("fields_type_annotations length=%d", fields_type_annotations->length());
2300
2301 for (int i = 0; i < fields_type_annotations->length(); i++) {
2302 AnnotationArray* field_type_annotations = fields_type_annotations->at(i);
2303 if (field_type_annotations == NULL || field_type_annotations->length() == 0) {
2304 // this field does not have any annotations so skip it
2305 continue;
2306 }
2307
2308 int byte_i = 0; // byte index into field_type_annotations
2309 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations,
2310 byte_i, "field_info", THREAD)) {
2311 log_debug(redefine, class, annotation)("bad field_type_annotations at %d", i);
2312 // propagate failure back to caller
2313 return false;
2314 }
2315 }
2316
2317 return true;
2318 } // end rewrite_cp_refs_in_fields_type_annotations()
2319
2320
2321 // Rewrite constant pool references in a methods_type_annotations field.
2322 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations(
2323 InstanceKlass* scratch_class, TRAPS) {
2324
2325 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2326 Method* m = scratch_class->methods()->at(i);
2327 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations();
2328
2329 if (method_type_annotations == NULL || method_type_annotations->length() == 0) {
2330 // this method does not have any annotations so skip it
2331 continue;
2332 }
2333
2334 log_debug(redefine, class, annotation)("methods type_annotations length=%d", method_type_annotations->length());
2335
2336 int byte_i = 0; // byte index into method_type_annotations
2337 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations,
2338 byte_i, "method_info", THREAD)) {
2339 log_debug(redefine, class, annotation)("bad method_type_annotations at %d", i);
2340 // propagate failure back to caller
2341 return false;
2342 }
2343 }
2344
2345 return true;
2346 } // end rewrite_cp_refs_in_methods_type_annotations()
2347
2348
2349 // Rewrite constant pool references in a type_annotations
2350 // field. This "structure" is adapted from the
2351 // RuntimeVisibleTypeAnnotations_attribute described in
2352 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2353 //
2354 // type_annotations_typeArray {
2355 // u2 num_annotations;
2356 // type_annotation annotations[num_annotations];
2357 // }
2358 //
2359 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray(
2360 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2361 const char * location_mesg, TRAPS) {
2362
2363 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2364 // not enough room for num_annotations field
2365 log_debug(redefine, class, annotation)("length() is too small for num_annotations field");
2366 return false;
2367 }
2368
2369 u2 num_annotations = Bytes::get_Java_u2((address)
2370 type_annotations_typeArray->adr_at(byte_i_ref));
2371 byte_i_ref += 2;
2372
2373 log_debug(redefine, class, annotation)("num_type_annotations=%d", num_annotations);
2374
2375 int calc_num_annotations = 0;
2376 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
2377 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray,
2378 byte_i_ref, location_mesg, THREAD)) {
2379 log_debug(redefine, class, annotation)("bad type_annotation_struct at %d", calc_num_annotations);
2380 // propagate failure back to caller
2381 return false;
2382 }
2383 }
2384 assert(num_annotations == calc_num_annotations, "sanity check");
2385
2386 if (byte_i_ref != type_annotations_typeArray->length()) {
2387 log_debug(redefine, class, annotation)
2388 ("read wrong amount of bytes at end of processing type_annotations_typeArray (%d of %d bytes were read)",
2389 byte_i_ref, type_annotations_typeArray->length());
2390 return false;
2391 }
2392
2393 return true;
2394 } // end rewrite_cp_refs_in_type_annotations_typeArray()
2395
2396
2397 // Rewrite constant pool references in a type_annotation
2398 // field. This "structure" is adapted from the
2399 // RuntimeVisibleTypeAnnotations_attribute described in
2400 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2401 //
2402 // type_annotation {
2403 // u1 target_type;
2404 // union {
2405 // type_parameter_target;
2406 // supertype_target;
2407 // type_parameter_bound_target;
2408 // empty_target;
2409 // method_formal_parameter_target;
2410 // throws_target;
2411 // localvar_target;
2412 // catch_target;
2413 // offset_target;
2414 // type_argument_target;
2415 // } target_info;
2416 // type_path target_path;
2417 // annotation anno;
2418 // }
2419 //
2420 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct(
2421 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2422 const char * location_mesg, TRAPS) {
2423
2424 if (!skip_type_annotation_target(type_annotations_typeArray,
2425 byte_i_ref, location_mesg, THREAD)) {
2426 return false;
2427 }
2428
2429 if (!skip_type_annotation_type_path(type_annotations_typeArray,
2430 byte_i_ref, THREAD)) {
2431 return false;
2432 }
2433
2434 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray,
2435 byte_i_ref, THREAD)) {
2436 return false;
2437 }
2438
2439 return true;
2440 } // end rewrite_cp_refs_in_type_annotation_struct()
2441
2442
2443 // Read, verify and skip over the target_type and target_info part
2444 // so that rewriting can continue in the later parts of the struct.
2445 //
2446 // u1 target_type;
2447 // union {
2448 // type_parameter_target;
2449 // supertype_target;
2450 // type_parameter_bound_target;
2451 // empty_target;
2452 // method_formal_parameter_target;
2453 // throws_target;
2454 // localvar_target;
2455 // catch_target;
2456 // offset_target;
2457 // type_argument_target;
2458 // } target_info;
2459 //
2460 bool VM_RedefineClasses::skip_type_annotation_target(
2461 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2462 const char * location_mesg, TRAPS) {
2463
2464 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2465 // not enough room for a target_type let alone the rest of a type_annotation
2466 log_debug(redefine, class, annotation)("length() is too small for a target_type");
2467 return false;
2468 }
2469
2470 u1 target_type = type_annotations_typeArray->at(byte_i_ref);
2471 byte_i_ref += 1;
2472 log_debug(redefine, class, annotation)("target_type=0x%.2x", target_type);
2473 log_debug(redefine, class, annotation)("location=%s", location_mesg);
2474
2475 // Skip over target_info
2476 switch (target_type) {
2477 case 0x00:
2478 // kind: type parameter declaration of generic class or interface
2479 // location: ClassFile
2480 case 0x01:
2481 // kind: type parameter declaration of generic method or constructor
2482 // location: method_info
2483
2484 {
2485 // struct:
2486 // type_parameter_target {
2487 // u1 type_parameter_index;
2488 // }
2489 //
2490 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2491 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_target");
2492 return false;
2493 }
2494
2495 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2496 byte_i_ref += 1;
2497
2498 log_debug(redefine, class, annotation)("type_parameter_target: type_parameter_index=%d", type_parameter_index);
2499 } break;
2500
2501 case 0x10:
2502 // kind: type in extends clause of class or interface declaration
2503 // (including the direct superclass of an anonymous class declaration),
2504 // or in implements clause of interface declaration
2505 // location: ClassFile
2506
2507 {
2508 // struct:
2509 // supertype_target {
2510 // u2 supertype_index;
2511 // }
2512 //
2513 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2514 log_debug(redefine, class, annotation)("length() is too small for a supertype_target");
2515 return false;
2516 }
2517
2518 u2 supertype_index = Bytes::get_Java_u2((address)
2519 type_annotations_typeArray->adr_at(byte_i_ref));
2520 byte_i_ref += 2;
2521
2522 log_debug(redefine, class, annotation)("supertype_target: supertype_index=%d", supertype_index);
2523 } break;
2524
2525 case 0x11:
2526 // kind: type in bound of type parameter declaration of generic class or interface
2527 // location: ClassFile
2528 case 0x12:
2529 // kind: type in bound of type parameter declaration of generic method or constructor
2530 // location: method_info
2531
2532 {
2533 // struct:
2534 // type_parameter_bound_target {
2535 // u1 type_parameter_index;
2536 // u1 bound_index;
2537 // }
2538 //
2539 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2540 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_bound_target");
2541 return false;
2542 }
2543
2544 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2545 byte_i_ref += 1;
2546 u1 bound_index = type_annotations_typeArray->at(byte_i_ref);
2547 byte_i_ref += 1;
2548
2549 log_debug(redefine, class, annotation)
2550 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d", type_parameter_index, bound_index);
2551 } break;
2552
2553 case 0x13:
2554 // kind: type in field declaration
2555 // location: field_info
2556 case 0x14:
2557 // kind: return type of method, or type of newly constructed object
2558 // location: method_info
2559 case 0x15:
2560 // kind: receiver type of method or constructor
2561 // location: method_info
2562
2563 {
2564 // struct:
2565 // empty_target {
2566 // }
2567 //
2568 log_debug(redefine, class, annotation)("empty_target");
2569 } break;
2570
2571 case 0x16:
2572 // kind: type in formal parameter declaration of method, constructor, or lambda expression
2573 // location: method_info
2574
2575 {
2576 // struct:
2577 // formal_parameter_target {
2578 // u1 formal_parameter_index;
2579 // }
2580 //
2581 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2582 log_debug(redefine, class, annotation)("length() is too small for a formal_parameter_target");
2583 return false;
2584 }
2585
2586 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2587 byte_i_ref += 1;
2588
2589 log_debug(redefine, class, annotation)
2590 ("formal_parameter_target: formal_parameter_index=%d", formal_parameter_index);
2591 } break;
2592
2593 case 0x17:
2594 // kind: type in throws clause of method or constructor
2595 // location: method_info
2596
2597 {
2598 // struct:
2599 // throws_target {
2600 // u2 throws_type_index
2601 // }
2602 //
2603 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2604 log_debug(redefine, class, annotation)("length() is too small for a throws_target");
2605 return false;
2606 }
2607
2608 u2 throws_type_index = Bytes::get_Java_u2((address)
2609 type_annotations_typeArray->adr_at(byte_i_ref));
2610 byte_i_ref += 2;
2611
2612 log_debug(redefine, class, annotation)("throws_target: throws_type_index=%d", throws_type_index);
2613 } break;
2614
2615 case 0x40:
2616 // kind: type in local variable declaration
2617 // location: Code
2618 case 0x41:
2619 // kind: type in resource variable declaration
2620 // location: Code
2621
2622 {
2623 // struct:
2624 // localvar_target {
2625 // u2 table_length;
2626 // struct {
2627 // u2 start_pc;
2628 // u2 length;
2629 // u2 index;
2630 // } table[table_length];
2631 // }
2632 //
2633 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2634 // not enough room for a table_length let alone the rest of a localvar_target
2635 log_debug(redefine, class, annotation)("length() is too small for a localvar_target table_length");
2636 return false;
2637 }
2638
2639 u2 table_length = Bytes::get_Java_u2((address)
2640 type_annotations_typeArray->adr_at(byte_i_ref));
2641 byte_i_ref += 2;
2642
2643 log_debug(redefine, class, annotation)("localvar_target: table_length=%d", table_length);
2644
2645 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry
2646 int table_size = table_length * table_struct_size;
2647
2648 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) {
2649 // not enough room for a table
2650 log_debug(redefine, class, annotation)("length() is too small for a table array of length %d", table_length);
2651 return false;
2652 }
2653
2654 // Skip over table
2655 byte_i_ref += table_size;
2656 } break;
2657
2658 case 0x42:
2659 // kind: type in exception parameter declaration
2660 // location: Code
2661
2662 {
2663 // struct:
2664 // catch_target {
2665 // u2 exception_table_index;
2666 // }
2667 //
2668 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2669 log_debug(redefine, class, annotation)("length() is too small for a catch_target");
2670 return false;
2671 }
2672
2673 u2 exception_table_index = Bytes::get_Java_u2((address)
2674 type_annotations_typeArray->adr_at(byte_i_ref));
2675 byte_i_ref += 2;
2676
2677 log_debug(redefine, class, annotation)("catch_target: exception_table_index=%d", exception_table_index);
2678 } break;
2679
2680 case 0x43:
2681 // kind: type in instanceof expression
2682 // location: Code
2683 case 0x44:
2684 // kind: type in new expression
2685 // location: Code
2686 case 0x45:
2687 // kind: type in method reference expression using ::new
2688 // location: Code
2689 case 0x46:
2690 // kind: type in method reference expression using ::Identifier
2691 // location: Code
2692
2693 {
2694 // struct:
2695 // offset_target {
2696 // u2 offset;
2697 // }
2698 //
2699 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2700 log_debug(redefine, class, annotation)("length() is too small for a offset_target");
2701 return false;
2702 }
2703
2704 u2 offset = Bytes::get_Java_u2((address)
2705 type_annotations_typeArray->adr_at(byte_i_ref));
2706 byte_i_ref += 2;
2707
2708 log_debug(redefine, class, annotation)("offset_target: offset=%d", offset);
2709 } break;
2710
2711 case 0x47:
2712 // kind: type in cast expression
2713 // location: Code
2714 case 0x48:
2715 // kind: type argument for generic constructor in new expression or
2716 // explicit constructor invocation statement
2717 // location: Code
2718 case 0x49:
2719 // kind: type argument for generic method in method invocation expression
2720 // location: Code
2721 case 0x4A:
2722 // kind: type argument for generic constructor in method reference expression using ::new
2723 // location: Code
2724 case 0x4B:
2725 // kind: type argument for generic method in method reference expression using ::Identifier
2726 // location: Code
2727
2728 {
2729 // struct:
2730 // type_argument_target {
2731 // u2 offset;
2732 // u1 type_argument_index;
2733 // }
2734 //
2735 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) {
2736 log_debug(redefine, class, annotation)("length() is too small for a type_argument_target");
2737 return false;
2738 }
2739
2740 u2 offset = Bytes::get_Java_u2((address)
2741 type_annotations_typeArray->adr_at(byte_i_ref));
2742 byte_i_ref += 2;
2743 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
2744 byte_i_ref += 1;
2745
2746 log_debug(redefine, class, annotation)
2747 ("type_argument_target: offset=%d, type_argument_index=%d", offset, type_argument_index);
2748 } break;
2749
2750 default:
2751 log_debug(redefine, class, annotation)("unknown target_type");
2752 #ifdef ASSERT
2753 ShouldNotReachHere();
2754 #endif
2755 return false;
2756 }
2757
2758 return true;
2759 } // end skip_type_annotation_target()
2760
2761
2762 // Read, verify and skip over the type_path part so that rewriting
2763 // can continue in the later parts of the struct.
2764 //
2765 // type_path {
2766 // u1 path_length;
2767 // {
2768 // u1 type_path_kind;
2769 // u1 type_argument_index;
2770 // } path[path_length];
2771 // }
2772 //
2773 bool VM_RedefineClasses::skip_type_annotation_type_path(
2774 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, TRAPS) {
2775
2776 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2777 // not enough room for a path_length let alone the rest of the type_path
2778 log_debug(redefine, class, annotation)("length() is too small for a type_path");
2779 return false;
2780 }
2781
2782 u1 path_length = type_annotations_typeArray->at(byte_i_ref);
2783 byte_i_ref += 1;
2784
2785 log_debug(redefine, class, annotation)("type_path: path_length=%d", path_length);
2786
2787 int calc_path_length = 0;
2788 for (; calc_path_length < path_length; calc_path_length++) {
2789 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) {
2790 // not enough room for a path
2791 log_debug(redefine, class, annotation)
2792 ("length() is too small for path entry %d of %d", calc_path_length, path_length);
2793 return false;
2794 }
2795
2796 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref);
2797 byte_i_ref += 1;
2798 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
2799 byte_i_ref += 1;
2800
2801 log_debug(redefine, class, annotation)
2802 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d",
2803 calc_path_length, type_path_kind, type_argument_index);
2804
2805 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) {
2806 // not enough room for a path
2807 log_debug(redefine, class, annotation)("inconsistent type_path values");
2808 return false;
2809 }
2810 }
2811 assert(path_length == calc_path_length, "sanity check");
2812
2813 return true;
2814 } // end skip_type_annotation_type_path()
2815
2816
2817 // Rewrite constant pool references in the method's stackmap table.
2818 // These "structures" are adapted from the StackMapTable_attribute that
2819 // is described in section 4.8.4 of the 6.0 version of the VM spec
2820 // (dated 2005.10.26):
2821 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2822 //
2823 // stack_map {
2824 // u2 number_of_entries;
2825 // stack_map_frame entries[number_of_entries];
2826 // }
2827 //
2828 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table(
2829 const methodHandle& method, TRAPS) {
2830
2831 if (!method->has_stackmap_table()) {
2832 return;
2833 }
2834
2835 AnnotationArray* stackmap_data = method->stackmap_data();
2836 address stackmap_p = (address)stackmap_data->adr_at(0);
2837 address stackmap_end = stackmap_p + stackmap_data->length();
2838
2839 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries");
2840 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p);
2841 stackmap_p += 2;
2842
2843 log_debug(redefine, class, stackmap)("number_of_entries=%u", number_of_entries);
2844
2845 // walk through each stack_map_frame
2846 u2 calc_number_of_entries = 0;
2847 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) {
2848 // The stack_map_frame structure is a u1 frame_type followed by
2849 // 0 or more bytes of data:
2850 //
2851 // union stack_map_frame {
2852 // same_frame;
2853 // same_locals_1_stack_item_frame;
2854 // same_locals_1_stack_item_frame_extended;
2855 // chop_frame;
2856 // same_frame_extended;
2857 // append_frame;
2858 // full_frame;
2859 // }
2860
2861 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type");
2862 u1 frame_type = *stackmap_p;
2863 stackmap_p++;
2864
2865 // same_frame {
2866 // u1 frame_type = SAME; /* 0-63 */
2867 // }
2868 if (frame_type <= 63) {
2869 // nothing more to do for same_frame
2870 }
2871
2872 // same_locals_1_stack_item_frame {
2873 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */
2874 // verification_type_info stack[1];
2875 // }
2876 else if (frame_type >= 64 && frame_type <= 127) {
2877 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2878 calc_number_of_entries, frame_type, THREAD);
2879 }
2880
2881 // reserved for future use
2882 else if (frame_type >= 128 && frame_type <= 246) {
2883 // nothing more to do for reserved frame_types
2884 }
2885
2886 // same_locals_1_stack_item_frame_extended {
2887 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */
2888 // u2 offset_delta;
2889 // verification_type_info stack[1];
2890 // }
2891 else if (frame_type == 247) {
2892 stackmap_p += 2;
2893 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2894 calc_number_of_entries, frame_type, THREAD);
2895 }
2896
2897 // chop_frame {
2898 // u1 frame_type = CHOP; /* 248-250 */
2899 // u2 offset_delta;
2900 // }
2901 else if (frame_type >= 248 && frame_type <= 250) {
2902 stackmap_p += 2;
2903 }
2904
2905 // same_frame_extended {
2906 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/
2907 // u2 offset_delta;
2908 // }
2909 else if (frame_type == 251) {
2910 stackmap_p += 2;
2911 }
2912
2913 // append_frame {
2914 // u1 frame_type = APPEND; /* 252-254 */
2915 // u2 offset_delta;
2916 // verification_type_info locals[frame_type - 251];
2917 // }
2918 else if (frame_type >= 252 && frame_type <= 254) {
2919 assert(stackmap_p + 2 <= stackmap_end,
2920 "no room for offset_delta");
2921 stackmap_p += 2;
2922 u1 len = frame_type - 251;
2923 for (u1 i = 0; i < len; i++) {
2924 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2925 calc_number_of_entries, frame_type, THREAD);
2926 }
2927 }
2928
2929 // full_frame {
2930 // u1 frame_type = FULL_FRAME; /* 255 */
2931 // u2 offset_delta;
2932 // u2 number_of_locals;
2933 // verification_type_info locals[number_of_locals];
2934 // u2 number_of_stack_items;
2935 // verification_type_info stack[number_of_stack_items];
2936 // }
2937 else if (frame_type == 255) {
2938 assert(stackmap_p + 2 + 2 <= stackmap_end,
2939 "no room for smallest full_frame");
2940 stackmap_p += 2;
2941
2942 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p);
2943 stackmap_p += 2;
2944
2945 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) {
2946 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2947 calc_number_of_entries, frame_type, THREAD);
2948 }
2949
2950 // Use the largest size for the number_of_stack_items, but only get
2951 // the right number of bytes.
2952 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p);
2953 stackmap_p += 2;
2954
2955 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) {
2956 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2957 calc_number_of_entries, frame_type, THREAD);
2958 }
2959 }
2960 } // end while there is a stack_map_frame
2961 assert(number_of_entries == calc_number_of_entries, "sanity check");
2962 } // end rewrite_cp_refs_in_stack_map_table()
2963
2964
2965 // Rewrite constant pool references in the verification type info
2966 // portion of the method's stackmap table. These "structures" are
2967 // adapted from the StackMapTable_attribute that is described in
2968 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26):
2969 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2970 //
2971 // The verification_type_info structure is a u1 tag followed by 0 or
2972 // more bytes of data:
2973 //
2974 // union verification_type_info {
2975 // Top_variable_info;
2976 // Integer_variable_info;
2977 // Float_variable_info;
2978 // Long_variable_info;
2979 // Double_variable_info;
2980 // Null_variable_info;
2981 // UninitializedThis_variable_info;
2982 // Object_variable_info;
2983 // Uninitialized_variable_info;
2984 // }
2985 //
2986 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info(
2987 address& stackmap_p_ref, address stackmap_end, u2 frame_i,
2988 u1 frame_type, TRAPS) {
2989
2990 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag");
2991 u1 tag = *stackmap_p_ref;
2992 stackmap_p_ref++;
2993
2994 switch (tag) {
2995 // Top_variable_info {
2996 // u1 tag = ITEM_Top; /* 0 */
2997 // }
2998 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top
2999 case 0: // fall through
3000
3001 // Integer_variable_info {
3002 // u1 tag = ITEM_Integer; /* 1 */
3003 // }
3004 case ITEM_Integer: // fall through
3005
3006 // Float_variable_info {
3007 // u1 tag = ITEM_Float; /* 2 */
3008 // }
3009 case ITEM_Float: // fall through
3010
3011 // Double_variable_info {
3012 // u1 tag = ITEM_Double; /* 3 */
3013 // }
3014 case ITEM_Double: // fall through
3015
3016 // Long_variable_info {
3017 // u1 tag = ITEM_Long; /* 4 */
3018 // }
3019 case ITEM_Long: // fall through
3020
3021 // Null_variable_info {
3022 // u1 tag = ITEM_Null; /* 5 */
3023 // }
3024 case ITEM_Null: // fall through
3025
3026 // UninitializedThis_variable_info {
3027 // u1 tag = ITEM_UninitializedThis; /* 6 */
3028 // }
3029 case ITEM_UninitializedThis:
3030 // nothing more to do for the above tag types
3031 break;
3032
3033 // Object_variable_info {
3034 // u1 tag = ITEM_Object; /* 7 */
3035 // u2 cpool_index;
3036 // }
3037 case ITEM_Object:
3038 {
3039 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index");
3040 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref);
3041 u2 new_cp_index = find_new_index(cpool_index);
3042 if (new_cp_index != 0) {
3043 log_debug(redefine, class, stackmap)("mapped old cpool_index=%d", cpool_index);
3044 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
3045 cpool_index = new_cp_index;
3046 }
3047 stackmap_p_ref += 2;
3048
3049 log_debug(redefine, class, stackmap)
3050 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i, frame_type, cpool_index);
3051 } break;
3052
3053 // Uninitialized_variable_info {
3054 // u1 tag = ITEM_Uninitialized; /* 8 */
3055 // u2 offset;
3056 // }
3057 case ITEM_Uninitialized:
3058 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset");
3059 stackmap_p_ref += 2;
3060 break;
3061
3062 default:
3063 log_debug(redefine, class, stackmap)("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag);
3064 ShouldNotReachHere();
3065 break;
3066 } // end switch (tag)
3067 } // end rewrite_cp_refs_in_verification_type_info()
3068
3069
3070 // Change the constant pool associated with klass scratch_class to
3071 // scratch_cp. If shrink is true, then scratch_cp_length elements
3072 // are copied from scratch_cp to a smaller constant pool and the
3073 // smaller constant pool is associated with scratch_class.
3074 void VM_RedefineClasses::set_new_constant_pool(
3075 ClassLoaderData* loader_data,
3076 InstanceKlass* scratch_class, constantPoolHandle scratch_cp,
3077 int scratch_cp_length, TRAPS) {
3078 assert(scratch_cp->length() >= scratch_cp_length, "sanity check");
3079
3080 // scratch_cp is a merged constant pool and has enough space for a
3081 // worst case merge situation. We want to associate the minimum
3082 // sized constant pool with the klass to save space.
3083 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK);
3084 constantPoolHandle smaller_cp(THREAD, cp);
3085
3086 // preserve version() value in the smaller copy
3087 int version = scratch_cp->version();
3088 assert(version != 0, "sanity check");
3089 smaller_cp->set_version(version);
3090
3091 // attach klass to new constant pool
3092 // reference to the cp holder is needed for copy_operands()
3093 smaller_cp->set_pool_holder(scratch_class);
3094
3095 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
3096 if (HAS_PENDING_EXCEPTION) {
3097 // Exception is handled in the caller
3098 loader_data->add_to_deallocate_list(smaller_cp());
3099 return;
3100 }
3101 scratch_cp = smaller_cp;
3102
3103 // attach new constant pool to klass
3104 scratch_class->set_constants(scratch_cp());
3105
3106 int i; // for portability
3107
3108 // update each field in klass to use new constant pool indices as needed
3109 for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) {
3110 jshort cur_index = fs.name_index();
3111 jshort new_index = find_new_index(cur_index);
3112 if (new_index != 0) {
3113 log_trace(redefine, class, constantpool)("field-name_index change: %d to %d", cur_index, new_index);
3114 fs.set_name_index(new_index);
3115 }
3116 cur_index = fs.signature_index();
3117 new_index = find_new_index(cur_index);
3118 if (new_index != 0) {
3119 log_trace(redefine, class, constantpool)("field-signature_index change: %d to %d", cur_index, new_index);
3120 fs.set_signature_index(new_index);
3121 }
3122 cur_index = fs.initval_index();
3123 new_index = find_new_index(cur_index);
3124 if (new_index != 0) {
3125 log_trace(redefine, class, constantpool)("field-initval_index change: %d to %d", cur_index, new_index);
3126 fs.set_initval_index(new_index);
3127 }
3128 cur_index = fs.generic_signature_index();
3129 new_index = find_new_index(cur_index);
3130 if (new_index != 0) {
3131 log_trace(redefine, class, constantpool)("field-generic_signature change: %d to %d", cur_index, new_index);
3132 fs.set_generic_signature_index(new_index);
3133 }
3134 } // end for each field
3135
3136 // Update constant pool indices in the inner classes info to use
3137 // new constant indices as needed. The inner classes info is a
3138 // quadruple:
3139 // (inner_class_info, outer_class_info, inner_name, inner_access_flags)
3140 InnerClassesIterator iter(scratch_class);
3141 for (; !iter.done(); iter.next()) {
3142 int cur_index = iter.inner_class_info_index();
3143 if (cur_index == 0) {
3144 continue; // JVM spec. allows null inner class refs so skip it
3145 }
3146 int new_index = find_new_index(cur_index);
3147 if (new_index != 0) {
3148 log_trace(redefine, class, constantpool)("inner_class_info change: %d to %d", cur_index, new_index);
3149 iter.set_inner_class_info_index(new_index);
3150 }
3151 cur_index = iter.outer_class_info_index();
3152 new_index = find_new_index(cur_index);
3153 if (new_index != 0) {
3154 log_trace(redefine, class, constantpool)("outer_class_info change: %d to %d", cur_index, new_index);
3155 iter.set_outer_class_info_index(new_index);
3156 }
3157 cur_index = iter.inner_name_index();
3158 new_index = find_new_index(cur_index);
3159 if (new_index != 0) {
3160 log_trace(redefine, class, constantpool)("inner_name change: %d to %d", cur_index, new_index);
3161 iter.set_inner_name_index(new_index);
3162 }
3163 } // end for each inner class
3164
3165 // Attach each method in klass to the new constant pool and update
3166 // to use new constant pool indices as needed:
3167 Array<Method*>* methods = scratch_class->methods();
3168 for (i = methods->length() - 1; i >= 0; i--) {
3169 methodHandle method(THREAD, methods->at(i));
3170 method->set_constants(scratch_cp());
3171
3172 int new_index = find_new_index(method->name_index());
3173 if (new_index != 0) {
3174 log_trace(redefine, class, constantpool)
3175 ("method-name_index change: %d to %d", method->name_index(), new_index);
3176 method->set_name_index(new_index);
3177 }
3178 new_index = find_new_index(method->signature_index());
3179 if (new_index != 0) {
3180 log_trace(redefine, class, constantpool)
3181 ("method-signature_index change: %d to %d", method->signature_index(), new_index);
3182 method->set_signature_index(new_index);
3183 }
3184 new_index = find_new_index(method->generic_signature_index());
3185 if (new_index != 0) {
3186 log_trace(redefine, class, constantpool)
3187 ("method-generic_signature_index change: %d to %d", method->generic_signature_index(), new_index);
3188 method->set_generic_signature_index(new_index);
3189 }
3190
3191 // Update constant pool indices in the method's checked exception
3192 // table to use new constant indices as needed.
3193 int cext_length = method->checked_exceptions_length();
3194 if (cext_length > 0) {
3195 CheckedExceptionElement * cext_table =
3196 method->checked_exceptions_start();
3197 for (int j = 0; j < cext_length; j++) {
3198 int cur_index = cext_table[j].class_cp_index;
3199 int new_index = find_new_index(cur_index);
3200 if (new_index != 0) {
3201 log_trace(redefine, class, constantpool)("cext-class_cp_index change: %d to %d", cur_index, new_index);
3202 cext_table[j].class_cp_index = (u2)new_index;
3203 }
3204 } // end for each checked exception table entry
3205 } // end if there are checked exception table entries
3206
3207 // Update each catch type index in the method's exception table
3208 // to use new constant pool indices as needed. The exception table
3209 // holds quadruple entries of the form:
3210 // (beg_bci, end_bci, handler_bci, klass_index)
3211
3212 ExceptionTable ex_table(method());
3213 int ext_length = ex_table.length();
3214
3215 for (int j = 0; j < ext_length; j ++) {
3216 int cur_index = ex_table.catch_type_index(j);
3217 int new_index = find_new_index(cur_index);
3218 if (new_index != 0) {
3219 log_trace(redefine, class, constantpool)("ext-klass_index change: %d to %d", cur_index, new_index);
3220 ex_table.set_catch_type_index(j, new_index);
3221 }
3222 } // end for each exception table entry
3223
3224 // Update constant pool indices in the method's local variable
3225 // table to use new constant indices as needed. The local variable
3226 // table hold sextuple entries of the form:
3227 // (start_pc, length, name_index, descriptor_index, signature_index, slot)
3228 int lvt_length = method->localvariable_table_length();
3229 if (lvt_length > 0) {
3230 LocalVariableTableElement * lv_table =
3231 method->localvariable_table_start();
3232 for (int j = 0; j < lvt_length; j++) {
3233 int cur_index = lv_table[j].name_cp_index;
3234 int new_index = find_new_index(cur_index);
3235 if (new_index != 0) {
3236 log_trace(redefine, class, constantpool)("lvt-name_cp_index change: %d to %d", cur_index, new_index);
3237 lv_table[j].name_cp_index = (u2)new_index;
3238 }
3239 cur_index = lv_table[j].descriptor_cp_index;
3240 new_index = find_new_index(cur_index);
3241 if (new_index != 0) {
3242 log_trace(redefine, class, constantpool)("lvt-descriptor_cp_index change: %d to %d", cur_index, new_index);
3243 lv_table[j].descriptor_cp_index = (u2)new_index;
3244 }
3245 cur_index = lv_table[j].signature_cp_index;
3246 new_index = find_new_index(cur_index);
3247 if (new_index != 0) {
3248 log_trace(redefine, class, constantpool)("lvt-signature_cp_index change: %d to %d", cur_index, new_index);
3249 lv_table[j].signature_cp_index = (u2)new_index;
3250 }
3251 } // end for each local variable table entry
3252 } // end if there are local variable table entries
3253
3254 rewrite_cp_refs_in_stack_map_table(method, THREAD);
3255 } // end for each method
3256 } // end set_new_constant_pool()
3257
3258
3259 // Unevolving classes may point to methods of the_class directly
3260 // from their constant pool caches, itables, and/or vtables. We
3261 // use the ClassLoaderDataGraph::classes_do() facility and this helper
3262 // to fix up these pointers.
3263
3264 // Adjust cpools and vtables closure
3265 void VM_RedefineClasses::AdjustCpoolCacheAndVtable::do_klass(Klass* k) {
3266
3267 // This is a very busy routine. We don't want too much tracing
3268 // printed out.
3269 bool trace_name_printed = false;
3270 InstanceKlass *the_class = InstanceKlass::cast(_the_class);
3271
3272 // If the class being redefined is java.lang.Object, we need to fix all
3273 // array class vtables also
3274 if (k->is_array_klass() && _the_class == SystemDictionary::Object_klass()) {
3275 k->vtable()->adjust_method_entries(the_class, &trace_name_printed);
3276
3277 } else if (k->is_instance_klass()) {
3278 HandleMark hm(_thread);
3279 InstanceKlass *ik = InstanceKlass::cast(k);
3280
3281 // HotSpot specific optimization! HotSpot does not currently
3282 // support delegation from the bootstrap class loader to a
3283 // user-defined class loader. This means that if the bootstrap
3284 // class loader is the initiating class loader, then it will also
3285 // be the defining class loader. This also means that classes
3286 // loaded by the bootstrap class loader cannot refer to classes
3287 // loaded by a user-defined class loader. Note: a user-defined
3288 // class loader can delegate to the bootstrap class loader.
3289 //
3290 // If the current class being redefined has a user-defined class
3291 // loader as its defining class loader, then we can skip all
3292 // classes loaded by the bootstrap class loader.
3293 bool is_user_defined = (_the_class->class_loader() != NULL);
3294 if (is_user_defined && ik->class_loader() == NULL) {
3295 return;
3296 }
3297
3298 // Fix the vtable embedded in the_class and subclasses of the_class,
3299 // if one exists. We discard scratch_class and we don't keep an
3300 // InstanceKlass around to hold obsolete methods so we don't have
3301 // any other InstanceKlass embedded vtables to update. The vtable
3302 // holds the Method*s for virtual (but not final) methods.
3303 // Default methods, or concrete methods in interfaces are stored
3304 // in the vtable, so if an interface changes we need to check
3305 // adjust_method_entries() for every InstanceKlass, which will also
3306 // adjust the default method vtable indices.
3307 // We also need to adjust any default method entries that are
3308 // not yet in the vtable, because the vtable setup is in progress.
3309 // This must be done after we adjust the default_methods and
3310 // default_vtable_indices for methods already in the vtable.
3311 // If redefining Unsafe, walk all the vtables looking for entries.
3312 if (ik->vtable_length() > 0 && (_the_class->is_interface()
3313 || _the_class == SystemDictionary::internal_Unsafe_klass()
3314 || ik->is_subtype_of(_the_class))) {
3315 // ik->vtable() creates a wrapper object; rm cleans it up
3316 ResourceMark rm(_thread);
3317
3318 ik->vtable()->adjust_method_entries(the_class, &trace_name_printed);
3319 ik->adjust_default_methods(the_class, &trace_name_printed);
3320 }
3321
3322 // If the current class has an itable and we are either redefining an
3323 // interface or if the current class is a subclass of the_class, then
3324 // we potentially have to fix the itable. If we are redefining an
3325 // interface, then we have to call adjust_method_entries() for
3326 // every InstanceKlass that has an itable since there isn't a
3327 // subclass relationship between an interface and an InstanceKlass.
3328 // If redefining Unsafe, walk all the itables looking for entries.
3329 if (ik->itable_length() > 0 && (_the_class->is_interface()
3330 || _the_class == SystemDictionary::internal_Unsafe_klass()
3331 || ik->is_subclass_of(_the_class))) {
3332 // ik->itable() creates a wrapper object; rm cleans it up
3333 ResourceMark rm(_thread);
3334
3335 ik->itable()->adjust_method_entries(the_class, &trace_name_printed);
3336 }
3337
3338 // The constant pools in other classes (other_cp) can refer to
3339 // methods in the_class. We have to update method information in
3340 // other_cp's cache. If other_cp has a previous version, then we
3341 // have to repeat the process for each previous version. The
3342 // constant pool cache holds the Method*s for non-virtual
3343 // methods and for virtual, final methods.
3344 //
3345 // Special case: if the current class is the_class, then new_cp
3346 // has already been attached to the_class and old_cp has already
3347 // been added as a previous version. The new_cp doesn't have any
3348 // cached references to old methods so it doesn't need to be
3349 // updated. We can simply start with the previous version(s) in
3350 // that case.
3351 constantPoolHandle other_cp;
3352 ConstantPoolCache* cp_cache;
3353
3354 if (ik != _the_class) {
3355 // this klass' constant pool cache may need adjustment
3356 other_cp = constantPoolHandle(ik->constants());
3357 cp_cache = other_cp->cache();
3358 if (cp_cache != NULL) {
3359 cp_cache->adjust_method_entries(the_class, &trace_name_printed);
3360 }
3361 }
3362
3363 // the previous versions' constant pool caches may need adjustment
3364 for (InstanceKlass* pv_node = ik->previous_versions();
3365 pv_node != NULL;
3366 pv_node = pv_node->previous_versions()) {
3367 cp_cache = pv_node->constants()->cache();
3368 if (cp_cache != NULL) {
3369 cp_cache->adjust_method_entries(pv_node, &trace_name_printed);
3370 }
3371 }
3372 }
3373 }
3374
3375 // Clean method data for this class
3376 void VM_RedefineClasses::MethodDataCleaner::do_klass(Klass* k) {
3377 if (k->is_instance_klass()) {
3378 InstanceKlass *ik = InstanceKlass::cast(k);
3379 // Clean MethodData of this class's methods so they don't refer to
3380 // old methods that are no longer running.
3381 Array<Method*>* methods = ik->methods();
3382 int num_methods = methods->length();
3383 for (int index = 0; index < num_methods; ++index) {
3384 if (methods->at(index)->method_data() != NULL) {
3385 methods->at(index)->method_data()->clean_weak_method_links();
3386 }
3387 }
3388 }
3389 }
3390
3391 void VM_RedefineClasses::update_jmethod_ids() {
3392 for (int j = 0; j < _matching_methods_length; ++j) {
3393 Method* old_method = _matching_old_methods[j];
3394 jmethodID jmid = old_method->find_jmethod_id_or_null();
3395 if (jmid != NULL) {
3396 // There is a jmethodID, change it to point to the new method
3397 methodHandle new_method_h(_matching_new_methods[j]);
3398 Method::change_method_associated_with_jmethod_id(jmid, new_method_h());
3399 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j],
3400 "should be replaced");
3401 }
3402 }
3403 }
3404
3405 int VM_RedefineClasses::check_methods_and_mark_as_obsolete() {
3406 int emcp_method_count = 0;
3407 int obsolete_count = 0;
3408 int old_index = 0;
3409 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
3410 Method* old_method = _matching_old_methods[j];
3411 Method* new_method = _matching_new_methods[j];
3412 Method* old_array_method;
3413
3414 // Maintain an old_index into the _old_methods array by skipping
3415 // deleted methods
3416 while ((old_array_method = _old_methods->at(old_index)) != old_method) {
3417 ++old_index;
3418 }
3419
3420 if (MethodComparator::methods_EMCP(old_method, new_method)) {
3421 // The EMCP definition from JSR-163 requires the bytecodes to be
3422 // the same with the exception of constant pool indices which may
3423 // differ. However, the constants referred to by those indices
3424 // must be the same.
3425 //
3426 // We use methods_EMCP() for comparison since constant pool
3427 // merging can remove duplicate constant pool entries that were
3428 // present in the old method and removed from the rewritten new
3429 // method. A faster binary comparison function would consider the
3430 // old and new methods to be different when they are actually
3431 // EMCP.
3432 //
3433 // The old and new methods are EMCP and you would think that we
3434 // could get rid of one of them here and now and save some space.
3435 // However, the concept of EMCP only considers the bytecodes and
3436 // the constant pool entries in the comparison. Other things,
3437 // e.g., the line number table (LNT) or the local variable table
3438 // (LVT) don't count in the comparison. So the new (and EMCP)
3439 // method can have a new LNT that we need so we can't just
3440 // overwrite the new method with the old method.
3441 //
3442 // When this routine is called, we have already attached the new
3443 // methods to the_class so the old methods are effectively
3444 // overwritten. However, if an old method is still executing,
3445 // then the old method cannot be collected until sometime after
3446 // the old method call has returned. So the overwriting of old
3447 // methods by new methods will save us space except for those
3448 // (hopefully few) old methods that are still executing.
3449 //
3450 // A method refers to a ConstMethod* and this presents another
3451 // possible avenue to space savings. The ConstMethod* in the
3452 // new method contains possibly new attributes (LNT, LVT, etc).
3453 // At first glance, it seems possible to save space by replacing
3454 // the ConstMethod* in the old method with the ConstMethod*
3455 // from the new method. The old and new methods would share the
3456 // same ConstMethod* and we would save the space occupied by
3457 // the old ConstMethod*. However, the ConstMethod* contains
3458 // a back reference to the containing method. Sharing the
3459 // ConstMethod* between two methods could lead to confusion in
3460 // the code that uses the back reference. This would lead to
3461 // brittle code that could be broken in non-obvious ways now or
3462 // in the future.
3463 //
3464 // Another possibility is to copy the ConstMethod* from the new
3465 // method to the old method and then overwrite the new method with
3466 // the old method. Since the ConstMethod* contains the bytecodes
3467 // for the method embedded in the oop, this option would change
3468 // the bytecodes out from under any threads executing the old
3469 // method and make the thread's bcp invalid. Since EMCP requires
3470 // that the bytecodes be the same modulo constant pool indices, it
3471 // is straight forward to compute the correct new bcp in the new
3472 // ConstMethod* from the old bcp in the old ConstMethod*. The
3473 // time consuming part would be searching all the frames in all
3474 // of the threads to find all of the calls to the old method.
3475 //
3476 // It looks like we will have to live with the limited savings
3477 // that we get from effectively overwriting the old methods
3478 // when the new methods are attached to the_class.
3479
3480 // Count number of methods that are EMCP. The method will be marked
3481 // old but not obsolete if it is EMCP.
3482 emcp_method_count++;
3483
3484 // An EMCP method is _not_ obsolete. An obsolete method has a
3485 // different jmethodID than the current method. An EMCP method
3486 // has the same jmethodID as the current method. Having the
3487 // same jmethodID for all EMCP versions of a method allows for
3488 // a consistent view of the EMCP methods regardless of which
3489 // EMCP method you happen to have in hand. For example, a
3490 // breakpoint set in one EMCP method will work for all EMCP
3491 // versions of the method including the current one.
3492 } else {
3493 // mark obsolete methods as such
3494 old_method->set_is_obsolete();
3495 obsolete_count++;
3496
3497 // obsolete methods need a unique idnum so they become new entries in
3498 // the jmethodID cache in InstanceKlass
3499 assert(old_method->method_idnum() == new_method->method_idnum(), "must match");
3500 u2 num = InstanceKlass::cast(_the_class)->next_method_idnum();
3501 if (num != ConstMethod::UNSET_IDNUM) {
3502 old_method->set_method_idnum(num);
3503 }
3504
3505 // With tracing we try not to "yack" too much. The position of
3506 // this trace assumes there are fewer obsolete methods than
3507 // EMCP methods.
3508 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) {
3509 ResourceMark rm;
3510 log_trace(redefine, class, obsolete, mark)
3511 ("mark %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string());
3512 }
3513 }
3514 old_method->set_is_old();
3515 }
3516 for (int i = 0; i < _deleted_methods_length; ++i) {
3517 Method* old_method = _deleted_methods[i];
3518
3519 assert(!old_method->has_vtable_index(),
3520 "cannot delete methods with vtable entries");;
3521
3522 // Mark all deleted methods as old, obsolete and deleted
3523 old_method->set_is_deleted();
3524 old_method->set_is_old();
3525 old_method->set_is_obsolete();
3526 ++obsolete_count;
3527 // With tracing we try not to "yack" too much. The position of
3528 // this trace assumes there are fewer obsolete methods than
3529 // EMCP methods.
3530 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) {
3531 ResourceMark rm;
3532 log_trace(redefine, class, obsolete, mark)
3533 ("mark deleted %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string());
3534 }
3535 }
3536 assert((emcp_method_count + obsolete_count) == _old_methods->length(),
3537 "sanity check");
3538 log_trace(redefine, class, obsolete, mark)("EMCP_cnt=%d, obsolete_cnt=%d", emcp_method_count, obsolete_count);
3539 return emcp_method_count;
3540 }
3541
3542 // This internal class transfers the native function registration from old methods
3543 // to new methods. It is designed to handle both the simple case of unchanged
3544 // native methods and the complex cases of native method prefixes being added and/or
3545 // removed.
3546 // It expects only to be used during the VM_RedefineClasses op (a safepoint).
3547 //
3548 // This class is used after the new methods have been installed in "the_class".
3549 //
3550 // So, for example, the following must be handled. Where 'm' is a method and
3551 // a number followed by an underscore is a prefix.
3552 //
3553 // Old Name New Name
3554 // Simple transfer to new method m -> m
3555 // Add prefix m -> 1_m
3556 // Remove prefix 1_m -> m
3557 // Simultaneous add of prefixes m -> 3_2_1_m
3558 // Simultaneous removal of prefixes 3_2_1_m -> m
3559 // Simultaneous add and remove 1_m -> 2_m
3560 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m
3561 //
3562 class TransferNativeFunctionRegistration {
3563 private:
3564 InstanceKlass* the_class;
3565 int prefix_count;
3566 char** prefixes;
3567
3568 // Recursively search the binary tree of possibly prefixed method names.
3569 // Iteration could be used if all agents were well behaved. Full tree walk is
3570 // more resilent to agents not cleaning up intermediate methods.
3571 // Branch at each depth in the binary tree is:
3572 // (1) without the prefix.
3573 // (2) with the prefix.
3574 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
3575 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len,
3576 Symbol* signature) {
3577 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len);
3578 if (name_symbol != NULL) {
3579 Method* method = the_class->lookup_method(name_symbol, signature);
3580 if (method != NULL) {
3581 // Even if prefixed, intermediate methods must exist.
3582 if (method->is_native()) {
3583 // Wahoo, we found a (possibly prefixed) version of the method, return it.
3584 return method;
3585 }
3586 if (depth < prefix_count) {
3587 // Try applying further prefixes (other than this one).
3588 method = search_prefix_name_space(depth+1, name_str, name_len, signature);
3589 if (method != NULL) {
3590 return method; // found
3591 }
3592
3593 // Try adding this prefix to the method name and see if it matches
3594 // another method name.
3595 char* prefix = prefixes[depth];
3596 size_t prefix_len = strlen(prefix);
3597 size_t trial_len = name_len + prefix_len;
3598 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
3599 strcpy(trial_name_str, prefix);
3600 strcat(trial_name_str, name_str);
3601 method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
3602 signature);
3603 if (method != NULL) {
3604 // If found along this branch, it was prefixed, mark as such
3605 method->set_is_prefixed_native();
3606 return method; // found
3607 }
3608 }
3609 }
3610 }
3611 return NULL; // This whole branch bore nothing
3612 }
3613
3614 // Return the method name with old prefixes stripped away.
3615 char* method_name_without_prefixes(Method* method) {
3616 Symbol* name = method->name();
3617 char* name_str = name->as_utf8();
3618
3619 // Old prefixing may be defunct, strip prefixes, if any.
3620 for (int i = prefix_count-1; i >= 0; i--) {
3621 char* prefix = prefixes[i];
3622 size_t prefix_len = strlen(prefix);
3623 if (strncmp(prefix, name_str, prefix_len) == 0) {
3624 name_str += prefix_len;
3625 }
3626 }
3627 return name_str;
3628 }
3629
3630 // Strip any prefixes off the old native method, then try to find a
3631 // (possibly prefixed) new native that matches it.
3632 Method* strip_and_search_for_new_native(Method* method) {
3633 ResourceMark rm;
3634 char* name_str = method_name_without_prefixes(method);
3635 return search_prefix_name_space(0, name_str, strlen(name_str),
3636 method->signature());
3637 }
3638
3639 public:
3640
3641 // Construct a native method transfer processor for this class.
3642 TransferNativeFunctionRegistration(InstanceKlass* _the_class) {
3643 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
3644
3645 the_class = _the_class;
3646 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
3647 }
3648
3649 // Attempt to transfer any of the old or deleted methods that are native
3650 void transfer_registrations(Method** old_methods, int methods_length) {
3651 for (int j = 0; j < methods_length; j++) {
3652 Method* old_method = old_methods[j];
3653
3654 if (old_method->is_native() && old_method->has_native_function()) {
3655 Method* new_method = strip_and_search_for_new_native(old_method);
3656 if (new_method != NULL) {
3657 // Actually set the native function in the new method.
3658 // Redefine does not send events (except CFLH), certainly not this
3659 // behind the scenes re-registration.
3660 new_method->set_native_function(old_method->native_function(),
3661 !Method::native_bind_event_is_interesting);
3662 }
3663 }
3664 }
3665 }
3666 };
3667
3668 // Don't lose the association between a native method and its JNI function.
3669 void VM_RedefineClasses::transfer_old_native_function_registrations(InstanceKlass* the_class) {
3670 TransferNativeFunctionRegistration transfer(the_class);
3671 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length);
3672 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length);
3673 }
3674
3675 // Deoptimize all compiled code that depends on this class.
3676 //
3677 // If the can_redefine_classes capability is obtained in the onload
3678 // phase then the compiler has recorded all dependencies from startup.
3679 // In that case we need only deoptimize and throw away all compiled code
3680 // that depends on the class.
3681 //
3682 // If can_redefine_classes is obtained sometime after the onload
3683 // phase then the dependency information may be incomplete. In that case
3684 // the first call to RedefineClasses causes all compiled code to be
3685 // thrown away. As can_redefine_classes has been obtained then
3686 // all future compilations will record dependencies so second and
3687 // subsequent calls to RedefineClasses need only throw away code
3688 // that depends on the class.
3689 //
3690 void VM_RedefineClasses::flush_dependent_code(InstanceKlass* ik, TRAPS) {
3691 assert_locked_or_safepoint(Compile_lock);
3692
3693 // All dependencies have been recorded from startup or this is a second or
3694 // subsequent use of RedefineClasses
3695 if (JvmtiExport::all_dependencies_are_recorded()) {
3696 CodeCache::flush_evol_dependents_on(ik);
3697 } else {
3698 CodeCache::mark_all_nmethods_for_deoptimization();
3699
3700 ResourceMark rm(THREAD);
3701 DeoptimizationMarker dm;
3702
3703 // Deoptimize all activations depending on marked nmethods
3704 Deoptimization::deoptimize_dependents();
3705
3706 // Make the dependent methods not entrant
3707 CodeCache::make_marked_nmethods_not_entrant();
3708
3709 // From now on we know that the dependency information is complete
3710 JvmtiExport::set_all_dependencies_are_recorded(true);
3711 }
3712 }
3713
3714 void VM_RedefineClasses::compute_added_deleted_matching_methods() {
3715 Method* old_method;
3716 Method* new_method;
3717
3718 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3719 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3720 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length());
3721 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3722
3723 _matching_methods_length = 0;
3724 _deleted_methods_length = 0;
3725 _added_methods_length = 0;
3726
3727 int nj = 0;
3728 int oj = 0;
3729 while (true) {
3730 if (oj >= _old_methods->length()) {
3731 if (nj >= _new_methods->length()) {
3732 break; // we've looked at everything, done
3733 }
3734 // New method at the end
3735 new_method = _new_methods->at(nj);
3736 _added_methods[_added_methods_length++] = new_method;
3737 ++nj;
3738 } else if (nj >= _new_methods->length()) {
3739 // Old method, at the end, is deleted
3740 old_method = _old_methods->at(oj);
3741 _deleted_methods[_deleted_methods_length++] = old_method;
3742 ++oj;
3743 } else {
3744 old_method = _old_methods->at(oj);
3745 new_method = _new_methods->at(nj);
3746 if (old_method->name() == new_method->name()) {
3747 if (old_method->signature() == new_method->signature()) {
3748 _matching_old_methods[_matching_methods_length ] = old_method;
3749 _matching_new_methods[_matching_methods_length++] = new_method;
3750 ++nj;
3751 ++oj;
3752 } else {
3753 // added overloaded have already been moved to the end,
3754 // so this is a deleted overloaded method
3755 _deleted_methods[_deleted_methods_length++] = old_method;
3756 ++oj;
3757 }
3758 } else { // names don't match
3759 if (old_method->name()->fast_compare(new_method->name()) > 0) {
3760 // new method
3761 _added_methods[_added_methods_length++] = new_method;
3762 ++nj;
3763 } else {
3764 // deleted method
3765 _deleted_methods[_deleted_methods_length++] = old_method;
3766 ++oj;
3767 }
3768 }
3769 }
3770 }
3771 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
3772 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
3773 }
3774
3775
3776 void VM_RedefineClasses::swap_annotations(InstanceKlass* the_class,
3777 InstanceKlass* scratch_class) {
3778 // Swap annotation fields values
3779 Annotations* old_annotations = the_class->annotations();
3780 the_class->set_annotations(scratch_class->annotations());
3781 scratch_class->set_annotations(old_annotations);
3782 }
3783
3784
3785 // Install the redefinition of a class:
3786 // - house keeping (flushing breakpoints and caches, deoptimizing
3787 // dependent compiled code)
3788 // - replacing parts in the_class with parts from scratch_class
3789 // - adding a weak reference to track the obsolete but interesting
3790 // parts of the_class
3791 // - adjusting constant pool caches and vtables in other classes
3792 // that refer to methods in the_class. These adjustments use the
3793 // ClassLoaderDataGraph::classes_do() facility which only allows
3794 // a helper method to be specified. The interesting parameters
3795 // that we would like to pass to the helper method are saved in
3796 // static global fields in the VM operation.
3797 void VM_RedefineClasses::redefine_single_class(jclass the_jclass,
3798 InstanceKlass* scratch_class, TRAPS) {
3799
3800 HandleMark hm(THREAD); // make sure handles from this call are freed
3801
3802 if (log_is_enabled(Info, redefine, class, timer)) {
3803 _timer_rsc_phase1.start();
3804 }
3805
3806 InstanceKlass* the_class = get_ik(the_jclass);
3807
3808 // Remove all breakpoints in methods of this class
3809 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
3810 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class);
3811
3812 // Deoptimize all compiled code that depends on this class
3813 flush_dependent_code(the_class, THREAD);
3814
3815 _old_methods = the_class->methods();
3816 _new_methods = scratch_class->methods();
3817 _the_class = the_class;
3818 compute_added_deleted_matching_methods();
3819 update_jmethod_ids();
3820
3821 // Attach new constant pool to the original klass. The original
3822 // klass still refers to the old constant pool (for now).
3823 scratch_class->constants()->set_pool_holder(the_class);
3824
3825 #if 0
3826 // In theory, with constant pool merging in place we should be able
3827 // to save space by using the new, merged constant pool in place of
3828 // the old constant pool(s). By "pool(s)" I mean the constant pool in
3829 // the klass version we are replacing now and any constant pool(s) in
3830 // previous versions of klass. Nice theory, doesn't work in practice.
3831 // When this code is enabled, even simple programs throw NullPointer
3832 // exceptions. I'm guessing that this is caused by some constant pool
3833 // cache difference between the new, merged constant pool and the
3834 // constant pool that was just being used by the klass. I'm keeping
3835 // this code around to archive the idea, but the code has to remain
3836 // disabled for now.
3837
3838 // Attach each old method to the new constant pool. This can be
3839 // done here since we are past the bytecode verification and
3840 // constant pool optimization phases.
3841 for (int i = _old_methods->length() - 1; i >= 0; i--) {
3842 Method* method = _old_methods->at(i);
3843 method->set_constants(scratch_class->constants());
3844 }
3845
3846 // NOTE: this doesn't work because you can redefine the same class in two
3847 // threads, each getting their own constant pool data appended to the
3848 // original constant pool. In order for the new methods to work when they
3849 // become old methods, they need to keep their updated copy of the constant pool.
3850
3851 {
3852 // walk all previous versions of the klass
3853 InstanceKlass *ik = the_class;
3854 PreviousVersionWalker pvw(ik);
3855 do {
3856 ik = pvw.next_previous_version();
3857 if (ik != NULL) {
3858
3859 // attach previous version of klass to the new constant pool
3860 ik->set_constants(scratch_class->constants());
3861
3862 // Attach each method in the previous version of klass to the
3863 // new constant pool
3864 Array<Method*>* prev_methods = ik->methods();
3865 for (int i = prev_methods->length() - 1; i >= 0; i--) {
3866 Method* method = prev_methods->at(i);
3867 method->set_constants(scratch_class->constants());
3868 }
3869 }
3870 } while (ik != NULL);
3871 }
3872 #endif
3873
3874 // Replace methods and constantpool
3875 the_class->set_methods(_new_methods);
3876 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods,
3877 // and to be able to undo operation easily.
3878
3879 Array<int>* old_ordering = the_class->method_ordering();
3880 the_class->set_method_ordering(scratch_class->method_ordering());
3881 scratch_class->set_method_ordering(old_ordering);
3882
3883 ConstantPool* old_constants = the_class->constants();
3884 the_class->set_constants(scratch_class->constants());
3885 scratch_class->set_constants(old_constants); // See the previous comment.
3886 #if 0
3887 // We are swapping the guts of "the new class" with the guts of "the
3888 // class". Since the old constant pool has just been attached to "the
3889 // new class", it seems logical to set the pool holder in the old
3890 // constant pool also. However, doing this will change the observable
3891 // class hierarchy for any old methods that are still executing. A
3892 // method can query the identity of its "holder" and this query uses
3893 // the method's constant pool link to find the holder. The change in
3894 // holding class from "the class" to "the new class" can confuse
3895 // things.
3896 //
3897 // Setting the old constant pool's holder will also cause
3898 // verification done during vtable initialization below to fail.
3899 // During vtable initialization, the vtable's class is verified to be
3900 // a subtype of the method's holder. The vtable's class is "the
3901 // class" and the method's holder is gotten from the constant pool
3902 // link in the method itself. For "the class"'s directly implemented
3903 // methods, the method holder is "the class" itself (as gotten from
3904 // the new constant pool). The check works fine in this case. The
3905 // check also works fine for methods inherited from super classes.
3906 //
3907 // Miranda methods are a little more complicated. A miranda method is
3908 // provided by an interface when the class implementing the interface
3909 // does not provide its own method. These interfaces are implemented
3910 // internally as an InstanceKlass. These special instanceKlasses
3911 // share the constant pool of the class that "implements" the
3912 // interface. By sharing the constant pool, the method holder of a
3913 // miranda method is the class that "implements" the interface. In a
3914 // non-redefine situation, the subtype check works fine. However, if
3915 // the old constant pool's pool holder is modified, then the check
3916 // fails because there is no class hierarchy relationship between the
3917 // vtable's class and "the new class".
3918
3919 old_constants->set_pool_holder(scratch_class());
3920 #endif
3921
3922 // track number of methods that are EMCP for add_previous_version() call below
3923 int emcp_method_count = check_methods_and_mark_as_obsolete();
3924 transfer_old_native_function_registrations(the_class);
3925
3926 // The class file bytes from before any retransformable agents mucked
3927 // with them was cached on the scratch class, move to the_class.
3928 // Note: we still want to do this if nothing needed caching since it
3929 // should get cleared in the_class too.
3930 if (the_class->get_cached_class_file_bytes() == 0) {
3931 // the_class doesn't have a cache yet so copy it
3932 the_class->set_cached_class_file(scratch_class->get_cached_class_file());
3933 }
3934 else if (scratch_class->get_cached_class_file_bytes() !=
3935 the_class->get_cached_class_file_bytes()) {
3936 // The same class can be present twice in the scratch classes list or there
3937 // are multiple concurrent RetransformClasses calls on different threads.
3938 // In such cases we have to deallocate scratch_class cached_class_file.
3939 os::free(scratch_class->get_cached_class_file());
3940 }
3941
3942 // NULL out in scratch class to not delete twice. The class to be redefined
3943 // always owns these bytes.
3944 scratch_class->set_cached_class_file(NULL);
3945
3946 // Replace inner_classes
3947 Array<u2>* old_inner_classes = the_class->inner_classes();
3948 the_class->set_inner_classes(scratch_class->inner_classes());
3949 scratch_class->set_inner_classes(old_inner_classes);
3950
3951 // Initialize the vtable and interface table after
3952 // methods have been rewritten
3953 {
3954 ResourceMark rm(THREAD);
3955 // no exception should happen here since we explicitly
3956 // do not check loader constraints.
3957 // compare_and_normalize_class_versions has already checked:
3958 // - classloaders unchanged, signatures unchanged
3959 // - all instanceKlasses for redefined classes reused & contents updated
3960 the_class->vtable()->initialize_vtable(false, THREAD);
3961 the_class->itable()->initialize_itable(false, THREAD);
3962 assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())), "redefine exception");
3963 }
3964
3965 // Leave arrays of jmethodIDs and itable index cache unchanged
3966
3967 // Copy the "source file name" attribute from new class version
3968 the_class->set_source_file_name_index(
3969 scratch_class->source_file_name_index());
3970
3971 // Copy the "source debug extension" attribute from new class version
3972 the_class->set_source_debug_extension(
3973 scratch_class->source_debug_extension(),
3974 scratch_class->source_debug_extension() == NULL ? 0 :
3975 (int)strlen(scratch_class->source_debug_extension()));
3976
3977 // Use of javac -g could be different in the old and the new
3978 if (scratch_class->access_flags().has_localvariable_table() !=
3979 the_class->access_flags().has_localvariable_table()) {
3980
3981 AccessFlags flags = the_class->access_flags();
3982 if (scratch_class->access_flags().has_localvariable_table()) {
3983 flags.set_has_localvariable_table();
3984 } else {
3985 flags.clear_has_localvariable_table();
3986 }
3987 the_class->set_access_flags(flags);
3988 }
3989
3990 swap_annotations(the_class, scratch_class);
3991
3992 // Replace minor version number of class file
3993 u2 old_minor_version = the_class->minor_version();
3994 the_class->set_minor_version(scratch_class->minor_version());
3995 scratch_class->set_minor_version(old_minor_version);
3996
3997 // Replace major version number of class file
3998 u2 old_major_version = the_class->major_version();
3999 the_class->set_major_version(scratch_class->major_version());
4000 scratch_class->set_major_version(old_major_version);
4001
4002 // Replace CP indexes for class and name+type of enclosing method
4003 u2 old_class_idx = the_class->enclosing_method_class_index();
4004 u2 old_method_idx = the_class->enclosing_method_method_index();
4005 the_class->set_enclosing_method_indices(
4006 scratch_class->enclosing_method_class_index(),
4007 scratch_class->enclosing_method_method_index());
4008 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx);
4009
4010 // Replace fingerprint data
4011 the_class->set_has_passed_fingerprint_check(scratch_class->has_passed_fingerprint_check());
4012 the_class->store_fingerprint(scratch_class->get_stored_fingerprint());
4013
4014 the_class->set_has_been_redefined();
4015
4016 if (!the_class->should_be_initialized()) {
4017 // Class was already initialized, so AOT has only seen the original version.
4018 // We need to let AOT look at it again.
4019 AOTLoader::load_for_klass(the_class, THREAD);
4020 }
4021
4022 // keep track of previous versions of this class
4023 the_class->add_previous_version(scratch_class, emcp_method_count);
4024
4025 _timer_rsc_phase1.stop();
4026 if (log_is_enabled(Info, redefine, class, timer)) {
4027 _timer_rsc_phase2.start();
4028 }
4029
4030 // Adjust constantpool caches and vtables for all classes
4031 // that reference methods of the evolved class.
4032 AdjustCpoolCacheAndVtable adjust_cpool_cache_and_vtable(THREAD);
4033 ClassLoaderDataGraph::classes_do(&adjust_cpool_cache_and_vtable);
4034
4035 // JSR-292 support
4036 MemberNameTable* mnt = the_class->member_names();
4037 if (mnt != NULL) {
4038 bool trace_name_printed = false;
4039 mnt->adjust_method_entries(the_class, &trace_name_printed);
4040 }
4041
4042 if (the_class->oop_map_cache() != NULL) {
4043 // Flush references to any obsolete methods from the oop map cache
4044 // so that obsolete methods are not pinned.
4045 the_class->oop_map_cache()->flush_obsolete_entries();
4046 }
4047
4048 increment_class_counter((InstanceKlass *)the_class, THREAD);
4049 {
4050 ResourceMark rm(THREAD);
4051 // increment the classRedefinedCount field in the_class and in any
4052 // direct and indirect subclasses of the_class
4053 log_info(redefine, class, load)
4054 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)",
4055 the_class->external_name(), java_lang_Class::classRedefinedCount(the_class->java_mirror()), os::available_memory() >> 10);
4056 Events::log_redefinition(THREAD, "redefined class name=%s, count=%d",
4057 the_class->external_name(),
4058 java_lang_Class::classRedefinedCount(the_class->java_mirror()));
4059
4060 }
4061 _timer_rsc_phase2.stop();
4062 } // end redefine_single_class()
4063
4064
4065 // Increment the classRedefinedCount field in the specific InstanceKlass
4066 // and in all direct and indirect subclasses.
4067 void VM_RedefineClasses::increment_class_counter(InstanceKlass *ik, TRAPS) {
4068 oop class_mirror = ik->java_mirror();
4069 Klass* class_oop = java_lang_Class::as_Klass(class_mirror);
4070 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
4071 java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
4072
4073 if (class_oop != _the_class) {
4074 // _the_class count is printed at end of redefine_single_class()
4075 log_debug(redefine, class, subclass)("updated count in subclass=%s to %d", ik->external_name(), new_count);
4076 }
4077
4078 for (Klass *subk = ik->subklass(); subk != NULL;
4079 subk = subk->next_sibling()) {
4080 if (subk->is_instance_klass()) {
4081 // Only update instanceKlasses
4082 InstanceKlass *subik = InstanceKlass::cast(subk);
4083 // recursively do subclasses of the current subclass
4084 increment_class_counter(subik, THREAD);
4085 }
4086 }
4087 }
4088
4089 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) {
4090 bool no_old_methods = true; // be optimistic
4091
4092 // Both array and instance classes have vtables.
4093 // a vtable should never contain old or obsolete methods
4094 ResourceMark rm(_thread);
4095 if (k->vtable_length() > 0 &&
4096 !k->vtable()->check_no_old_or_obsolete_entries()) {
4097 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4098 log_trace(redefine, class, obsolete, metadata)
4099 ("klassVtable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4100 k->signature_name());
4101 k->vtable()->dump_vtable();
4102 }
4103 no_old_methods = false;
4104 }
4105
4106 if (k->is_instance_klass()) {
4107 HandleMark hm(_thread);
4108 InstanceKlass *ik = InstanceKlass::cast(k);
4109
4110 // an itable should never contain old or obsolete methods
4111 if (ik->itable_length() > 0 &&
4112 !ik->itable()->check_no_old_or_obsolete_entries()) {
4113 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4114 log_trace(redefine, class, obsolete, metadata)
4115 ("klassItable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4116 ik->signature_name());
4117 ik->itable()->dump_itable();
4118 }
4119 no_old_methods = false;
4120 }
4121
4122 // the constant pool cache should never contain non-deleted old or obsolete methods
4123 if (ik->constants() != NULL &&
4124 ik->constants()->cache() != NULL &&
4125 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) {
4126 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4127 log_trace(redefine, class, obsolete, metadata)
4128 ("cp-cache::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4129 ik->signature_name());
4130 ik->constants()->cache()->dump_cache();
4131 }
4132 no_old_methods = false;
4133 }
4134 }
4135
4136 // print and fail guarantee if old methods are found.
4137 if (!no_old_methods) {
4138 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4139 dump_methods();
4140 } else {
4141 log_trace(redefine, class)("Use the '-Xlog:redefine+class*:' option "
4142 "to see more info about the following guarantee() failure.");
4143 }
4144 guarantee(false, "OLD and/or OBSOLETE method(s) found");
4145 }
4146 }
4147
4148
4149 void VM_RedefineClasses::dump_methods() {
4150 int j;
4151 log_trace(redefine, class, dump)("_old_methods --");
4152 for (j = 0; j < _old_methods->length(); ++j) {
4153 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4154 Method* m = _old_methods->at(j);
4155 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4156 m->access_flags().print_on(&log_stream);
4157 log_stream.print(" -- ");
4158 m->print_name(&log_stream);
4159 log_stream.cr();
4160 }
4161 log_trace(redefine, class, dump)("_new_methods --");
4162 for (j = 0; j < _new_methods->length(); ++j) {
4163 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4164 Method* m = _new_methods->at(j);
4165 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4166 m->access_flags().print_on(&log_stream);
4167 log_stream.print(" -- ");
4168 m->print_name(&log_stream);
4169 log_stream.cr();
4170 }
4171 log_trace(redefine, class, dump)("_matching_methods --");
4172 for (j = 0; j < _matching_methods_length; ++j) {
4173 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4174 Method* m = _matching_old_methods[j];
4175 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4176 m->access_flags().print_on(&log_stream);
4177 log_stream.print(" -- ");
4178 m->print_name();
4179 log_stream.cr();
4180
4181 m = _matching_new_methods[j];
4182 log_stream.print(" (%5d) ", m->vtable_index());
4183 m->access_flags().print_on(&log_stream);
4184 log_stream.cr();
4185 }
4186 log_trace(redefine, class, dump)("_deleted_methods --");
4187 for (j = 0; j < _deleted_methods_length; ++j) {
4188 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4189 Method* m = _deleted_methods[j];
4190 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4191 m->access_flags().print_on(&log_stream);
4192 log_stream.print(" -- ");
4193 m->print_name(&log_stream);
4194 log_stream.cr();
4195 }
4196 log_trace(redefine, class, dump)("_added_methods --");
4197 for (j = 0; j < _added_methods_length; ++j) {
4198 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4199 Method* m = _added_methods[j];
4200 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4201 m->access_flags().print_on(&log_stream);
4202 log_stream.print(" -- ");
4203 m->print_name(&log_stream);
4204 log_stream.cr();
4205 }
4206 }
4207
4208 void VM_RedefineClasses::print_on_error(outputStream* st) const {
4209 VM_Operation::print_on_error(st);
4210 if (_the_class != NULL) {
4211 ResourceMark rm;
4212 st->print_cr(", redefining class %s", _the_class->external_name());
4213 }
4214 }