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 //
296 // this is an indirect CP entry so it needs special handling
297 case JVM_CONSTANT_Class:
298 case JVM_CONSTANT_UnresolvedClass:
299 {
300 int name_i = scratch_cp->klass_name_index_at(scratch_i);
301 int new_name_i = find_or_append_indirect_entry(scratch_cp, name_i, merge_cp_p,
302 merge_cp_length_p, THREAD);
303
304 if (new_name_i != name_i) {
305 log_trace(redefine, class, constantpool)
306 ("Class entry@%d name_index change: %d to %d",
307 *merge_cp_length_p, name_i, new_name_i);
308 }
309
310 (*merge_cp_p)->temp_unresolved_klass_at_put(*merge_cp_length_p, new_name_i);
311 if (scratch_i != *merge_cp_length_p) {
312 // The new entry in *merge_cp_p is at a different index than
313 // the new entry in scratch_cp so we need to map the index values.
314 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
315 }
316 (*merge_cp_length_p)++;
317 } break;
318
319 // these are direct CP entries so they can be directly appended,
320 // but double and long take two constant pool entries
321 case JVM_CONSTANT_Double: // fall through
322 case JVM_CONSTANT_Long:
323 {
324 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
325 THREAD);
326
327 if (scratch_i != *merge_cp_length_p) {
328 // The new entry in *merge_cp_p is at a different index than
329 // the new entry in scratch_cp so we need to map the index values.
330 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
331 }
332 (*merge_cp_length_p) += 2;
333 } break;
334
335 // these are direct CP entries so they can be directly appended
336 case JVM_CONSTANT_Float: // fall through
337 case JVM_CONSTANT_Integer: // fall through
338 case JVM_CONSTANT_Utf8: // fall through
339
340 // This was an indirect CP entry, but it has been changed into
341 // Symbol*s so this entry can be directly appended.
342 case JVM_CONSTANT_String: // fall through
343 {
344 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
345 THREAD);
346
347 if (scratch_i != *merge_cp_length_p) {
348 // The new entry in *merge_cp_p is at a different index than
349 // the new entry in scratch_cp so we need to map the index values.
350 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
351 }
352 (*merge_cp_length_p)++;
353 } break;
354
355 // this is an indirect CP entry so it needs special handling
356 case JVM_CONSTANT_NameAndType:
357 {
358 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i);
359 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p,
360 merge_cp_length_p, THREAD);
361
362 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i);
363 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i,
364 merge_cp_p, merge_cp_length_p,
365 THREAD);
366
367 // If the referenced entries already exist in *merge_cp_p, then
368 // both new_name_ref_i and new_signature_ref_i will both be 0.
369 // In that case, all we are appending is the current entry.
370 if (new_name_ref_i != name_ref_i) {
371 log_trace(redefine, class, constantpool)
372 ("NameAndType entry@%d name_ref_index change: %d to %d",
373 *merge_cp_length_p, name_ref_i, new_name_ref_i);
374 }
375 if (new_signature_ref_i != signature_ref_i) {
376 log_trace(redefine, class, constantpool)
377 ("NameAndType entry@%d signature_ref_index change: %d to %d",
378 *merge_cp_length_p, signature_ref_i, new_signature_ref_i);
379 }
380
381 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p,
382 new_name_ref_i, new_signature_ref_i);
383 if (scratch_i != *merge_cp_length_p) {
384 // The new entry in *merge_cp_p is at a different index than
385 // the new entry in scratch_cp so we need to map the index values.
386 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
387 }
388 (*merge_cp_length_p)++;
389 } break;
390
391 // this is a double-indirect CP entry so it needs special handling
392 case JVM_CONSTANT_Fieldref: // fall through
393 case JVM_CONSTANT_InterfaceMethodref: // fall through
394 case JVM_CONSTANT_Methodref:
395 {
396 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i);
397 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i,
398 merge_cp_p, merge_cp_length_p, THREAD);
399
400 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i);
401 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i,
402 merge_cp_p, merge_cp_length_p, THREAD);
403
404 const char *entry_name = NULL;
405 switch (scratch_cp->tag_at(scratch_i).value()) {
406 case JVM_CONSTANT_Fieldref:
407 entry_name = "Fieldref";
408 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i,
409 new_name_and_type_ref_i);
410 break;
411 case JVM_CONSTANT_InterfaceMethodref:
412 entry_name = "IFMethodref";
413 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p,
414 new_klass_ref_i, new_name_and_type_ref_i);
415 break;
416 case JVM_CONSTANT_Methodref:
417 entry_name = "Methodref";
418 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i,
419 new_name_and_type_ref_i);
420 break;
421 default:
422 guarantee(false, "bad switch");
423 break;
424 }
425
426 if (klass_ref_i != new_klass_ref_i) {
427 log_trace(redefine, class, constantpool)
428 ("%s entry@%d class_index changed: %d to %d", entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i);
429 }
430 if (name_and_type_ref_i != new_name_and_type_ref_i) {
431 log_trace(redefine, class, constantpool)
432 ("%s entry@%d name_and_type_index changed: %d to %d",
433 entry_name, *merge_cp_length_p, name_and_type_ref_i, new_name_and_type_ref_i);
434 }
435
436 if (scratch_i != *merge_cp_length_p) {
437 // The new entry in *merge_cp_p is at a different index than
438 // the new entry in scratch_cp so we need to map the index values.
439 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
440 }
441 (*merge_cp_length_p)++;
442 } break;
443
444 // this is an indirect CP entry so it needs special handling
445 case JVM_CONSTANT_MethodType:
446 {
447 int ref_i = scratch_cp->method_type_index_at(scratch_i);
448 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
449 merge_cp_length_p, THREAD);
450 if (new_ref_i != ref_i) {
451 log_trace(redefine, class, constantpool)
452 ("MethodType entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i);
453 }
454 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i);
455 if (scratch_i != *merge_cp_length_p) {
456 // The new entry in *merge_cp_p is at a different index than
457 // the new entry in scratch_cp so we need to map the index values.
458 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
459 }
460 (*merge_cp_length_p)++;
461 } break;
462
463 // this is an indirect CP entry so it needs special handling
464 case JVM_CONSTANT_MethodHandle:
465 {
466 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i);
467 int ref_i = scratch_cp->method_handle_index_at(scratch_i);
468 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
469 merge_cp_length_p, THREAD);
470 if (new_ref_i != ref_i) {
471 log_trace(redefine, class, constantpool)
472 ("MethodHandle entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i);
473 }
474 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i);
475 if (scratch_i != *merge_cp_length_p) {
476 // The new entry in *merge_cp_p is at a different index than
477 // the new entry in scratch_cp so we need to map the index values.
478 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
479 }
480 (*merge_cp_length_p)++;
481 } break;
482
483 // this is an indirect CP entry so it needs special handling
484 case JVM_CONSTANT_InvokeDynamic:
485 {
486 // Index of the bootstrap specifier in the operands array
487 int old_bs_i = scratch_cp->invoke_dynamic_bootstrap_specifier_index(scratch_i);
488 int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p,
489 merge_cp_length_p, THREAD);
490 // The bootstrap method NameAndType_info index
491 int old_ref_i = scratch_cp->invoke_dynamic_name_and_type_ref_index_at(scratch_i);
492 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
493 merge_cp_length_p, THREAD);
494 if (new_bs_i != old_bs_i) {
495 log_trace(redefine, class, constantpool)
496 ("InvokeDynamic entry@%d bootstrap_method_attr_index change: %d to %d",
497 *merge_cp_length_p, old_bs_i, new_bs_i);
498 }
499 if (new_ref_i != old_ref_i) {
500 log_trace(redefine, class, constantpool)
501 ("InvokeDynamic entry@%d name_and_type_index change: %d to %d", *merge_cp_length_p, old_ref_i, new_ref_i);
502 }
503
504 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
505 if (scratch_i != *merge_cp_length_p) {
506 // The new entry in *merge_cp_p is at a different index than
507 // the new entry in scratch_cp so we need to map the index values.
508 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
509 }
510 (*merge_cp_length_p)++;
511 } break;
512
513 // At this stage, Class or UnresolvedClass could be in scratch_cp, but not
514 // ClassIndex
515 case JVM_CONSTANT_ClassIndex: // fall through
516
517 // Invalid is used as the tag for the second constant pool entry
518 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
519 // not be seen by itself.
520 case JVM_CONSTANT_Invalid: // fall through
521
522 // At this stage, String could be here, but not StringIndex
523 case JVM_CONSTANT_StringIndex: // fall through
524
525 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be
526 // here
527 case JVM_CONSTANT_UnresolvedClassInError: // fall through
528
529 default:
530 {
531 // leave a breadcrumb
532 jbyte bad_value = scratch_cp->tag_at(scratch_i).value();
533 ShouldNotReachHere();
534 } break;
535 } // end switch tag value
536 } // end append_entry()
537
538
539 int VM_RedefineClasses::find_or_append_indirect_entry(const constantPoolHandle& scratch_cp,
540 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
541
542 int new_ref_i = ref_i;
543 bool match = (ref_i < *merge_cp_length_p) &&
544 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i, THREAD);
545
546 if (!match) {
547 // forward reference in *merge_cp_p or not a direct match
548 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p, THREAD);
549 if (found_i != 0) {
550 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree");
551 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry.
552 new_ref_i = found_i;
553 map_index(scratch_cp, ref_i, found_i);
554 } else {
555 // no match found so we have to append this entry to *merge_cp_p
556 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p, THREAD);
557 // The above call to append_entry() can only append one entry
558 // so the post call query of *merge_cp_length_p is only for
559 // the sake of consistency.
560 new_ref_i = *merge_cp_length_p - 1;
561 }
562 }
563
564 return new_ref_i;
565 } // end find_or_append_indirect_entry()
566
567
568 // Append a bootstrap specifier into the merge_cp operands that is semantically equal
569 // to the scratch_cp operands bootstrap specifier passed by the old_bs_i index.
570 // Recursively append new merge_cp entries referenced by the new bootstrap specifier.
571 void VM_RedefineClasses::append_operand(const constantPoolHandle& scratch_cp, int old_bs_i,
572 constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
573
574 int old_ref_i = scratch_cp->operand_bootstrap_method_ref_index_at(old_bs_i);
575 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
576 merge_cp_length_p, THREAD);
577 if (new_ref_i != old_ref_i) {
578 log_trace(redefine, class, constantpool)
579 ("operands entry@%d bootstrap method ref_index change: %d to %d", _operands_cur_length, old_ref_i, new_ref_i);
580 }
581
582 Array<u2>* merge_ops = (*merge_cp_p)->operands();
583 int new_bs_i = _operands_cur_length;
584 // We have _operands_cur_length == 0 when the merge_cp operands is empty yet.
585 // However, the operand_offset_at(0) was set in the extend_operands() call.
586 int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0)
587 : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1);
588 int argc = scratch_cp->operand_argument_count_at(old_bs_i);
589
590 ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base);
591 merge_ops->at_put(new_base++, new_ref_i);
592 merge_ops->at_put(new_base++, argc);
593
594 for (int i = 0; i < argc; i++) {
595 int old_arg_ref_i = scratch_cp->operand_argument_index_at(old_bs_i, i);
596 int new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p,
597 merge_cp_length_p, THREAD);
598 merge_ops->at_put(new_base++, new_arg_ref_i);
599 if (new_arg_ref_i != old_arg_ref_i) {
600 log_trace(redefine, class, constantpool)
601 ("operands entry@%d bootstrap method argument ref_index change: %d to %d",
602 _operands_cur_length, old_arg_ref_i, new_arg_ref_i);
603 }
604 }
605 if (old_bs_i != _operands_cur_length) {
606 // The bootstrap specifier in *merge_cp_p is at a different index than
607 // that in scratch_cp so we need to map the index values.
608 map_operand_index(old_bs_i, new_bs_i);
609 }
610 _operands_cur_length++;
611 } // end append_operand()
612
613
614 int VM_RedefineClasses::find_or_append_operand(const constantPoolHandle& scratch_cp,
615 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
616
617 int new_bs_i = old_bs_i; // bootstrap specifier index
618 bool match = (old_bs_i < _operands_cur_length) &&
619 scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i, THREAD);
620
621 if (!match) {
622 // forward reference in *merge_cp_p or not a direct match
623 int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p,
624 _operands_cur_length, THREAD);
625 if (found_i != -1) {
626 guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree");
627 // found a matching operand somewhere else in *merge_cp_p so just need a mapping
628 new_bs_i = found_i;
629 map_operand_index(old_bs_i, found_i);
630 } else {
631 // no match found so we have to append this bootstrap specifier to *merge_cp_p
632 append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p, THREAD);
633 new_bs_i = _operands_cur_length - 1;
634 }
635 }
636 return new_bs_i;
637 } // end find_or_append_operand()
638
639
640 void VM_RedefineClasses::finalize_operands_merge(const constantPoolHandle& merge_cp, TRAPS) {
641 if (merge_cp->operands() == NULL) {
642 return;
643 }
644 // Shrink the merge_cp operands
645 merge_cp->shrink_operands(_operands_cur_length, CHECK);
646
647 if (log_is_enabled(Trace, redefine, class, constantpool)) {
648 // don't want to loop unless we are tracing
649 int count = 0;
650 for (int i = 1; i < _operands_index_map_p->length(); i++) {
651 int value = _operands_index_map_p->at(i);
652 if (value != -1) {
653 log_trace(redefine, class, constantpool)("operands_index_map[%d]: old=%d new=%d", count, i, value);
654 count++;
655 }
656 }
657 }
658 // Clean-up
659 _operands_index_map_p = NULL;
660 _operands_cur_length = 0;
661 _operands_index_map_count = 0;
662 } // end finalize_operands_merge()
663
664
665 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions(
666 InstanceKlass* the_class,
667 InstanceKlass* scratch_class) {
668 int i;
669
670 // Check superclasses, or rather their names, since superclasses themselves can be
671 // requested to replace.
672 // Check for NULL superclass first since this might be java.lang.Object
673 if (the_class->super() != scratch_class->super() &&
674 (the_class->super() == NULL || scratch_class->super() == NULL ||
675 the_class->super()->name() !=
676 scratch_class->super()->name())) {
677 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
678 }
679
680 // Check if the number, names and order of directly implemented interfaces are the same.
681 // I think in principle we should just check if the sets of names of directly implemented
682 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the
683 // .java file, also changes in .class file) should not matter. However, comparing sets is
684 // technically a bit more difficult, and, more importantly, I am not sure at present that the
685 // order of interfaces does not matter on the implementation level, i.e. that the VM does not
686 // rely on it somewhere.
687 Array<Klass*>* k_interfaces = the_class->local_interfaces();
688 Array<Klass*>* k_new_interfaces = scratch_class->local_interfaces();
689 int n_intfs = k_interfaces->length();
690 if (n_intfs != k_new_interfaces->length()) {
691 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
692 }
693 for (i = 0; i < n_intfs; i++) {
694 if (k_interfaces->at(i)->name() !=
695 k_new_interfaces->at(i)->name()) {
696 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
697 }
698 }
699
700 // Check whether class is in the error init state.
701 if (the_class->is_in_error_state()) {
702 // TBD #5057930: special error code is needed in 1.6
703 return JVMTI_ERROR_INVALID_CLASS;
704 }
705
706 // Check whether class modifiers are the same.
707 jushort old_flags = (jushort) the_class->access_flags().get_flags();
708 jushort new_flags = (jushort) scratch_class->access_flags().get_flags();
709 if (old_flags != new_flags) {
710 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED;
711 }
712
713 // Check if the number, names, types and order of fields declared in these classes
714 // are the same.
715 JavaFieldStream old_fs(the_class);
716 JavaFieldStream new_fs(scratch_class);
717 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) {
718 // access
719 old_flags = old_fs.access_flags().as_short();
720 new_flags = new_fs.access_flags().as_short();
721 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) {
722 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
723 }
724 // offset
725 if (old_fs.offset() != new_fs.offset()) {
726 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
727 }
728 // name and signature
729 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index());
730 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index());
731 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index());
732 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index());
733 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) {
734 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
735 }
736 }
737
738 // If both streams aren't done then we have a differing number of
739 // fields.
740 if (!old_fs.done() || !new_fs.done()) {
741 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
742 }
743
744 // Do a parallel walk through the old and new methods. Detect
745 // cases where they match (exist in both), have been added in
746 // the new methods, or have been deleted (exist only in the
747 // old methods). The class file parser places methods in order
748 // by method name, but does not order overloaded methods by
749 // signature. In order to determine what fate befell the methods,
750 // this code places the overloaded new methods that have matching
751 // old methods in the same order as the old methods and places
752 // new overloaded methods at the end of overloaded methods of
753 // that name. The code for this order normalization is adapted
754 // from the algorithm used in InstanceKlass::find_method().
755 // Since we are swapping out of order entries as we find them,
756 // we only have to search forward through the overloaded methods.
757 // Methods which are added and have the same name as an existing
758 // method (but different signature) will be put at the end of
759 // the methods with that name, and the name mismatch code will
760 // handle them.
761 Array<Method*>* k_old_methods(the_class->methods());
762 Array<Method*>* k_new_methods(scratch_class->methods());
763 int n_old_methods = k_old_methods->length();
764 int n_new_methods = k_new_methods->length();
765 Thread* thread = Thread::current();
766
767 int ni = 0;
768 int oi = 0;
769 while (true) {
770 Method* k_old_method;
771 Method* k_new_method;
772 enum { matched, added, deleted, undetermined } method_was = undetermined;
773
774 if (oi >= n_old_methods) {
775 if (ni >= n_new_methods) {
776 break; // we've looked at everything, done
777 }
778 // New method at the end
779 k_new_method = k_new_methods->at(ni);
780 method_was = added;
781 } else if (ni >= n_new_methods) {
782 // Old method, at the end, is deleted
783 k_old_method = k_old_methods->at(oi);
784 method_was = deleted;
785 } else {
786 // There are more methods in both the old and new lists
787 k_old_method = k_old_methods->at(oi);
788 k_new_method = k_new_methods->at(ni);
789 if (k_old_method->name() != k_new_method->name()) {
790 // Methods are sorted by method name, so a mismatch means added
791 // or deleted
792 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) {
793 method_was = added;
794 } else {
795 method_was = deleted;
796 }
797 } else if (k_old_method->signature() == k_new_method->signature()) {
798 // Both the name and signature match
799 method_was = matched;
800 } else {
801 // The name matches, but the signature doesn't, which means we have to
802 // search forward through the new overloaded methods.
803 int nj; // outside the loop for post-loop check
804 for (nj = ni + 1; nj < n_new_methods; nj++) {
805 Method* m = k_new_methods->at(nj);
806 if (k_old_method->name() != m->name()) {
807 // reached another method name so no more overloaded methods
808 method_was = deleted;
809 break;
810 }
811 if (k_old_method->signature() == m->signature()) {
812 // found a match so swap the methods
813 k_new_methods->at_put(ni, m);
814 k_new_methods->at_put(nj, k_new_method);
815 k_new_method = m;
816 method_was = matched;
817 break;
818 }
819 }
820
821 if (nj >= n_new_methods) {
822 // reached the end without a match; so method was deleted
823 method_was = deleted;
824 }
825 }
826 }
827
828 switch (method_was) {
829 case matched:
830 // methods match, be sure modifiers do too
831 old_flags = (jushort) k_old_method->access_flags().get_flags();
832 new_flags = (jushort) k_new_method->access_flags().get_flags();
833 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) {
834 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED;
835 }
836 {
837 u2 new_num = k_new_method->method_idnum();
838 u2 old_num = k_old_method->method_idnum();
839 if (new_num != old_num) {
840 Method* idnum_owner = scratch_class->method_with_idnum(old_num);
841 if (idnum_owner != NULL) {
842 // There is already a method assigned this idnum -- switch them
843 // Take current and original idnum from the new_method
844 idnum_owner->set_method_idnum(new_num);
845 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum());
846 }
847 // Take current and original idnum from the old_method
848 k_new_method->set_method_idnum(old_num);
849 k_new_method->set_orig_method_idnum(k_old_method->orig_method_idnum());
850 if (thread->has_pending_exception()) {
851 return JVMTI_ERROR_OUT_OF_MEMORY;
852 }
853 }
854 }
855 log_trace(redefine, class, normalize)
856 ("Method matched: new: %s [%d] == old: %s [%d]",
857 k_new_method->name_and_sig_as_C_string(), ni, k_old_method->name_and_sig_as_C_string(), oi);
858 // advance to next pair of methods
859 ++oi;
860 ++ni;
861 break;
862 case added:
863 // method added, see if it is OK
864 new_flags = (jushort) k_new_method->access_flags().get_flags();
865 if ((new_flags & JVM_ACC_PRIVATE) == 0
866 // hack: private should be treated as final, but alas
867 || (new_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
868 ) {
869 // new methods must be private
870 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
871 }
872 {
873 u2 num = the_class->next_method_idnum();
874 if (num == ConstMethod::UNSET_IDNUM) {
875 // cannot add any more methods
876 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
877 }
878 u2 new_num = k_new_method->method_idnum();
879 Method* idnum_owner = scratch_class->method_with_idnum(num);
880 if (idnum_owner != NULL) {
881 // There is already a method assigned this idnum -- switch them
882 // Take current and original idnum from the new_method
883 idnum_owner->set_method_idnum(new_num);
884 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum());
885 }
886 k_new_method->set_method_idnum(num);
887 k_new_method->set_orig_method_idnum(num);
888 if (thread->has_pending_exception()) {
889 return JVMTI_ERROR_OUT_OF_MEMORY;
890 }
891 }
892 log_trace(redefine, class, normalize)
893 ("Method added: new: %s [%d]", k_new_method->name_and_sig_as_C_string(), ni);
894 ++ni; // advance to next new method
895 break;
896 case deleted:
897 // method deleted, see if it is OK
898 old_flags = (jushort) k_old_method->access_flags().get_flags();
899 if ((old_flags & JVM_ACC_PRIVATE) == 0
900 // hack: private should be treated as final, but alas
901 || (old_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
902 ) {
903 // deleted methods must be private
904 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED;
905 }
906 log_trace(redefine, class, normalize)
907 ("Method deleted: old: %s [%d]", k_old_method->name_and_sig_as_C_string(), oi);
908 ++oi; // advance to next old method
909 break;
910 default:
911 ShouldNotReachHere();
912 }
913 }
914
915 return JVMTI_ERROR_NONE;
916 }
917
918
919 // Find new constant pool index value for old constant pool index value
920 // by seaching the index map. Returns zero (0) if there is no mapped
921 // value for the old constant pool index.
922 int VM_RedefineClasses::find_new_index(int old_index) {
923 if (_index_map_count == 0) {
924 // map is empty so nothing can be found
925 return 0;
926 }
927
928 if (old_index < 1 || old_index >= _index_map_p->length()) {
929 // The old_index is out of range so it is not mapped. This should
930 // not happen in regular constant pool merging use, but it can
931 // happen if a corrupt annotation is processed.
932 return 0;
933 }
934
935 int value = _index_map_p->at(old_index);
936 if (value == -1) {
937 // the old_index is not mapped
938 return 0;
939 }
940
941 return value;
942 } // end find_new_index()
943
944
945 // Find new bootstrap specifier index value for old bootstrap specifier index
946 // value by seaching the index map. Returns unused index (-1) if there is
947 // no mapped value for the old bootstrap specifier index.
948 int VM_RedefineClasses::find_new_operand_index(int old_index) {
949 if (_operands_index_map_count == 0) {
950 // map is empty so nothing can be found
951 return -1;
952 }
953
954 if (old_index == -1 || old_index >= _operands_index_map_p->length()) {
955 // The old_index is out of range so it is not mapped.
956 // This should not happen in regular constant pool merging use.
957 return -1;
958 }
959
960 int value = _operands_index_map_p->at(old_index);
961 if (value == -1) {
962 // the old_index is not mapped
963 return -1;
964 }
965
966 return value;
967 } // end find_new_operand_index()
968
969
970 // Returns true if the current mismatch is due to a resolved/unresolved
971 // class pair. Otherwise, returns false.
972 bool VM_RedefineClasses::is_unresolved_class_mismatch(const constantPoolHandle& cp1,
973 int index1, const constantPoolHandle& cp2, int index2) {
974
975 jbyte t1 = cp1->tag_at(index1).value();
976 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) {
977 return false; // wrong entry type; not our special case
978 }
979
980 jbyte t2 = cp2->tag_at(index2).value();
981 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) {
982 return false; // wrong entry type; not our special case
983 }
984
985 if (t1 == t2) {
986 return false; // not a mismatch; not our special case
987 }
988
989 char *s1 = cp1->klass_name_at(index1)->as_C_string();
990 char *s2 = cp2->klass_name_at(index2)->as_C_string();
991 if (strcmp(s1, s2) != 0) {
992 return false; // strings don't match; not our special case
993 }
994
995 return true; // made it through the gauntlet; this is our special case
996 } // end is_unresolved_class_mismatch()
997
998
999 jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) {
1000
1001 // For consistency allocate memory using os::malloc wrapper.
1002 _scratch_classes = (InstanceKlass**)
1003 os::malloc(sizeof(InstanceKlass*) * _class_count, mtClass);
1004 if (_scratch_classes == NULL) {
1005 return JVMTI_ERROR_OUT_OF_MEMORY;
1006 }
1007 // Zero initialize the _scratch_classes array.
1008 for (int i = 0; i < _class_count; i++) {
1009 _scratch_classes[i] = NULL;
1010 }
1011
1012 ResourceMark rm(THREAD);
1013
1014 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
1015 // state can only be NULL if the current thread is exiting which
1016 // should not happen since we're trying to do a RedefineClasses
1017 guarantee(state != NULL, "exiting thread calling load_new_class_versions");
1018 for (int i = 0; i < _class_count; i++) {
1019 // Create HandleMark so that any handles created while loading new class
1020 // versions are deleted. Constant pools are deallocated while merging
1021 // constant pools
1022 HandleMark hm(THREAD);
1023 InstanceKlass* the_class = get_ik(_class_defs[i].klass);
1024 Symbol* the_class_sym = the_class->name();
1025
1026 log_debug(redefine, class, load)
1027 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)",
1028 the_class->external_name(), _class_load_kind, os::available_memory() >> 10);
1029
1030 ClassFileStream st((u1*)_class_defs[i].class_bytes,
1031 _class_defs[i].class_byte_count,
1032 "__VM_RedefineClasses__",
1033 ClassFileStream::verify);
1034
1035 // Parse the stream.
1036 Handle the_class_loader(THREAD, the_class->class_loader());
1037 Handle protection_domain(THREAD, the_class->protection_domain());
1038 // Set redefined class handle in JvmtiThreadState class.
1039 // This redefined class is sent to agent event handler for class file
1040 // load hook event.
1041 state->set_class_being_redefined(the_class, _class_load_kind);
1042
1043 InstanceKlass* scratch_class = SystemDictionary::parse_stream(
1044 the_class_sym,
1045 the_class_loader,
1046 protection_domain,
1047 &st,
1048 THREAD);
1049 // Clear class_being_redefined just to be sure.
1050 state->clear_class_being_redefined();
1051
1052 // TODO: if this is retransform, and nothing changed we can skip it
1053
1054 // Need to clean up allocated InstanceKlass if there's an error so assign
1055 // the result here. Caller deallocates all the scratch classes in case of
1056 // an error.
1057 _scratch_classes[i] = scratch_class;
1058
1059 if (HAS_PENDING_EXCEPTION) {
1060 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1061 log_info(redefine, class, load, exceptions)("parse_stream exception: '%s'", ex_name->as_C_string());
1062 CLEAR_PENDING_EXCEPTION;
1063
1064 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) {
1065 return JVMTI_ERROR_UNSUPPORTED_VERSION;
1066 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) {
1067 return JVMTI_ERROR_INVALID_CLASS_FORMAT;
1068 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) {
1069 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION;
1070 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
1071 // The message will be "XXX (wrong name: YYY)"
1072 return JVMTI_ERROR_NAMES_DONT_MATCH;
1073 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1074 return JVMTI_ERROR_OUT_OF_MEMORY;
1075 } else { // Just in case more exceptions can be thrown..
1076 return JVMTI_ERROR_FAILS_VERIFICATION;
1077 }
1078 }
1079
1080 // Ensure class is linked before redefine
1081 if (!the_class->is_linked()) {
1082 the_class->link_class(THREAD);
1083 if (HAS_PENDING_EXCEPTION) {
1084 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1085 log_info(redefine, class, load, exceptions)("link_class exception: '%s'", ex_name->as_C_string());
1086 CLEAR_PENDING_EXCEPTION;
1087 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1088 return JVMTI_ERROR_OUT_OF_MEMORY;
1089 } else {
1090 return JVMTI_ERROR_INTERNAL;
1091 }
1092 }
1093 }
1094
1095 // Do the validity checks in compare_and_normalize_class_versions()
1096 // before verifying the byte codes. By doing these checks first, we
1097 // limit the number of functions that require redirection from
1098 // the_class to scratch_class. In particular, we don't have to
1099 // modify JNI GetSuperclass() and thus won't change its performance.
1100 jvmtiError res = compare_and_normalize_class_versions(the_class,
1101 scratch_class);
1102 if (res != JVMTI_ERROR_NONE) {
1103 return res;
1104 }
1105
1106 // verify what the caller passed us
1107 {
1108 // The bug 6214132 caused the verification to fail.
1109 // Information about the_class and scratch_class is temporarily
1110 // recorded into jvmtiThreadState. This data is used to redirect
1111 // the_class to scratch_class in the JVM_* functions called by the
1112 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed
1113 // description.
1114 RedefineVerifyMark rvm(the_class, scratch_class, state);
1115 Verifier::verify(
1116 scratch_class, Verifier::ThrowException, true, THREAD);
1117 }
1118
1119 if (HAS_PENDING_EXCEPTION) {
1120 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1121 log_info(redefine, class, load, exceptions)("verify_byte_codes exception: '%s'", ex_name->as_C_string());
1122 CLEAR_PENDING_EXCEPTION;
1123 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1124 return JVMTI_ERROR_OUT_OF_MEMORY;
1125 } else {
1126 // tell the caller the bytecodes are bad
1127 return JVMTI_ERROR_FAILS_VERIFICATION;
1128 }
1129 }
1130
1131 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD);
1132 if (HAS_PENDING_EXCEPTION) {
1133 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1134 log_info(redefine, class, load, exceptions)("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string());
1135 CLEAR_PENDING_EXCEPTION;
1136 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1137 return JVMTI_ERROR_OUT_OF_MEMORY;
1138 } else {
1139 return JVMTI_ERROR_INTERNAL;
1140 }
1141 }
1142
1143 if (VerifyMergedCPBytecodes) {
1144 // verify what we have done during constant pool merging
1145 {
1146 RedefineVerifyMark rvm(the_class, scratch_class, state);
1147 Verifier::verify(scratch_class, Verifier::ThrowException, true, THREAD);
1148 }
1149
1150 if (HAS_PENDING_EXCEPTION) {
1151 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1152 log_info(redefine, class, load, exceptions)
1153 ("verify_byte_codes post merge-CP exception: '%s'", ex_name->as_C_string());
1154 CLEAR_PENDING_EXCEPTION;
1155 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1156 return JVMTI_ERROR_OUT_OF_MEMORY;
1157 } else {
1158 // tell the caller that constant pool merging screwed up
1159 return JVMTI_ERROR_INTERNAL;
1160 }
1161 }
1162 }
1163
1164 Rewriter::rewrite(scratch_class, THREAD);
1165 if (!HAS_PENDING_EXCEPTION) {
1166 scratch_class->link_methods(THREAD);
1167 }
1168 if (HAS_PENDING_EXCEPTION) {
1169 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1170 log_info(redefine, class, load, exceptions)
1171 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string());
1172 CLEAR_PENDING_EXCEPTION;
1173 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1174 return JVMTI_ERROR_OUT_OF_MEMORY;
1175 } else {
1176 return JVMTI_ERROR_INTERNAL;
1177 }
1178 }
1179
1180 log_debug(redefine, class, load)
1181 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)", the_class->external_name(), os::available_memory() >> 10);
1182 }
1183
1184 return JVMTI_ERROR_NONE;
1185 }
1186
1187
1188 // Map old_index to new_index as needed. scratch_cp is only needed
1189 // for log calls.
1190 void VM_RedefineClasses::map_index(const constantPoolHandle& scratch_cp,
1191 int old_index, int new_index) {
1192 if (find_new_index(old_index) != 0) {
1193 // old_index is already mapped
1194 return;
1195 }
1196
1197 if (old_index == new_index) {
1198 // no mapping is needed
1199 return;
1200 }
1201
1202 _index_map_p->at_put(old_index, new_index);
1203 _index_map_count++;
1204
1205 log_trace(redefine, class, constantpool)
1206 ("mapped tag %d at index %d to %d", scratch_cp->tag_at(old_index).value(), old_index, new_index);
1207 } // end map_index()
1208
1209
1210 // Map old_index to new_index as needed.
1211 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) {
1212 if (find_new_operand_index(old_index) != -1) {
1213 // old_index is already mapped
1214 return;
1215 }
1216
1217 if (old_index == new_index) {
1218 // no mapping is needed
1219 return;
1220 }
1221
1222 _operands_index_map_p->at_put(old_index, new_index);
1223 _operands_index_map_count++;
1224
1225 log_trace(redefine, class, constantpool)("mapped bootstrap specifier at index %d to %d", old_index, new_index);
1226 } // end map_index()
1227
1228
1229 // Merge old_cp and scratch_cp and return the results of the merge via
1230 // merge_cp_p. The number of entries in *merge_cp_p is returned via
1231 // merge_cp_length_p. The entries in old_cp occupy the same locations
1232 // in *merge_cp_p. Also creates a map of indices from entries in
1233 // scratch_cp to the corresponding entry in *merge_cp_p. Index map
1234 // entries are only created for entries in scratch_cp that occupy a
1235 // different location in *merged_cp_p.
1236 bool VM_RedefineClasses::merge_constant_pools(const constantPoolHandle& old_cp,
1237 const constantPoolHandle& scratch_cp, constantPoolHandle *merge_cp_p,
1238 int *merge_cp_length_p, TRAPS) {
1239
1240 if (merge_cp_p == NULL) {
1241 assert(false, "caller must provide scratch constantPool");
1242 return false; // robustness
1243 }
1244 if (merge_cp_length_p == NULL) {
1245 assert(false, "caller must provide scratch CP length");
1246 return false; // robustness
1247 }
1248 // Worst case we need old_cp->length() + scratch_cp()->length(),
1249 // but the caller might be smart so make sure we have at least
1250 // the minimum.
1251 if ((*merge_cp_p)->length() < old_cp->length()) {
1252 assert(false, "merge area too small");
1253 return false; // robustness
1254 }
1255
1256 log_info(redefine, class, constantpool)("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(), scratch_cp->length());
1257
1258 {
1259 // Pass 0:
1260 // The old_cp is copied to *merge_cp_p; this means that any code
1261 // using old_cp does not have to change. This work looks like a
1262 // perfect fit for ConstantPool*::copy_cp_to(), but we need to
1263 // handle one special case:
1264 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass
1265 // This will make verification happy.
1266
1267 int old_i; // index into old_cp
1268
1269 // index zero (0) is not used in constantPools
1270 for (old_i = 1; old_i < old_cp->length(); old_i++) {
1271 // leave debugging crumb
1272 jbyte old_tag = old_cp->tag_at(old_i).value();
1273 switch (old_tag) {
1274 case JVM_CONSTANT_Class:
1275 case JVM_CONSTANT_UnresolvedClass:
1276 // revert the copy to JVM_CONSTANT_UnresolvedClass
1277 // May be resolving while calling this so do the same for
1278 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition)
1279 (*merge_cp_p)->temp_unresolved_klass_at_put(old_i,
1280 old_cp->klass_name_index_at(old_i));
1281 break;
1282
1283 case JVM_CONSTANT_Double:
1284 case JVM_CONSTANT_Long:
1285 // just copy the entry to *merge_cp_p, but double and long take
1286 // two constant pool entries
1287 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1288 old_i++;
1289 break;
1290
1291 default:
1292 // just copy the entry to *merge_cp_p
1293 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1294 break;
1295 }
1296 } // end for each old_cp entry
1297
1298 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_0);
1299 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_0);
1300
1301 // We don't need to sanity check that *merge_cp_length_p is within
1302 // *merge_cp_p bounds since we have the minimum on-entry check above.
1303 (*merge_cp_length_p) = old_i;
1304 }
1305
1306 // merge_cp_len should be the same as old_cp->length() at this point
1307 // so this trace message is really a "warm-and-breathing" message.
1308 log_debug(redefine, class, constantpool)("after pass 0: merge_cp_len=%d", *merge_cp_length_p);
1309
1310 int scratch_i; // index into scratch_cp
1311 {
1312 // Pass 1a:
1313 // Compare scratch_cp entries to the old_cp entries that we have
1314 // already copied to *merge_cp_p. In this pass, we are eliminating
1315 // exact duplicates (matching entry at same index) so we only
1316 // compare entries in the common indice range.
1317 int increment = 1;
1318 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length());
1319 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) {
1320 switch (scratch_cp->tag_at(scratch_i).value()) {
1321 case JVM_CONSTANT_Double:
1322 case JVM_CONSTANT_Long:
1323 // double and long take two constant pool entries
1324 increment = 2;
1325 break;
1326
1327 default:
1328 increment = 1;
1329 break;
1330 }
1331
1332 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p,
1333 scratch_i, CHECK_0);
1334 if (match) {
1335 // found a match at the same index so nothing more to do
1336 continue;
1337 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i,
1338 *merge_cp_p, scratch_i)) {
1339 // The mismatch in compare_entry_to() above is because of a
1340 // resolved versus unresolved class entry at the same index
1341 // with the same string value. Since Pass 0 reverted any
1342 // class entries to unresolved class entries in *merge_cp_p,
1343 // we go with the unresolved class entry.
1344 continue;
1345 }
1346
1347 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p,
1348 CHECK_0);
1349 if (found_i != 0) {
1350 guarantee(found_i != scratch_i,
1351 "compare_entry_to() and find_matching_entry() do not agree");
1352
1353 // Found a matching entry somewhere else in *merge_cp_p so
1354 // just need a mapping entry.
1355 map_index(scratch_cp, scratch_i, found_i);
1356 continue;
1357 }
1358
1359 // The find_matching_entry() call above could fail to find a match
1360 // due to a resolved versus unresolved class or string entry situation
1361 // like we solved above with the is_unresolved_*_mismatch() calls.
1362 // However, we would have to call is_unresolved_*_mismatch() over
1363 // all of *merge_cp_p (potentially) and that doesn't seem to be
1364 // worth the time.
1365
1366 // No match found so we have to append this entry and any unique
1367 // referenced entries to *merge_cp_p.
1368 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1369 CHECK_0);
1370 }
1371 }
1372
1373 log_debug(redefine, class, constantpool)
1374 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1375 *merge_cp_length_p, scratch_i, _index_map_count);
1376
1377 if (scratch_i < scratch_cp->length()) {
1378 // Pass 1b:
1379 // old_cp is smaller than scratch_cp so there are entries in
1380 // scratch_cp that we have not yet processed. We take care of
1381 // those now.
1382 int increment = 1;
1383 for (; scratch_i < scratch_cp->length(); scratch_i += increment) {
1384 switch (scratch_cp->tag_at(scratch_i).value()) {
1385 case JVM_CONSTANT_Double:
1386 case JVM_CONSTANT_Long:
1387 // double and long take two constant pool entries
1388 increment = 2;
1389 break;
1390
1391 default:
1392 increment = 1;
1393 break;
1394 }
1395
1396 int found_i =
1397 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0);
1398 if (found_i != 0) {
1399 // Found a matching entry somewhere else in *merge_cp_p so
1400 // just need a mapping entry.
1401 map_index(scratch_cp, scratch_i, found_i);
1402 continue;
1403 }
1404
1405 // No match found so we have to append this entry and any unique
1406 // referenced entries to *merge_cp_p.
1407 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1408 CHECK_0);
1409 }
1410
1411 log_debug(redefine, class, constantpool)
1412 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1413 *merge_cp_length_p, scratch_i, _index_map_count);
1414 }
1415 finalize_operands_merge(*merge_cp_p, THREAD);
1416
1417 return true;
1418 } // end merge_constant_pools()
1419
1420
1421 // Scoped object to clean up the constant pool(s) created for merging
1422 class MergeCPCleaner {
1423 ClassLoaderData* _loader_data;
1424 ConstantPool* _cp;
1425 ConstantPool* _scratch_cp;
1426 public:
1427 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) :
1428 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {}
1429 ~MergeCPCleaner() {
1430 _loader_data->add_to_deallocate_list(_cp);
1431 if (_scratch_cp != NULL) {
1432 _loader_data->add_to_deallocate_list(_scratch_cp);
1433 }
1434 }
1435 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; }
1436 };
1437
1438 // Merge constant pools between the_class and scratch_class and
1439 // potentially rewrite bytecodes in scratch_class to use the merged
1440 // constant pool.
1441 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite(
1442 InstanceKlass* the_class, InstanceKlass* scratch_class,
1443 TRAPS) {
1444 // worst case merged constant pool length is old and new combined
1445 int merge_cp_length = the_class->constants()->length()
1446 + scratch_class->constants()->length();
1447
1448 // Constant pools are not easily reused so we allocate a new one
1449 // each time.
1450 // merge_cp is created unsafe for concurrent GC processing. It
1451 // should be marked safe before discarding it. Even though
1452 // garbage, if it crosses a card boundary, it may be scanned
1453 // in order to find the start of the first complete object on the card.
1454 ClassLoaderData* loader_data = the_class->class_loader_data();
1455 ConstantPool* merge_cp_oop =
1456 ConstantPool::allocate(loader_data,
1457 merge_cp_length,
1458 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1459 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop);
1460
1461 HandleMark hm(THREAD); // make sure handles are cleared before
1462 // MergeCPCleaner clears out merge_cp_oop
1463 constantPoolHandle merge_cp(THREAD, merge_cp_oop);
1464
1465 // Get constants() from the old class because it could have been rewritten
1466 // while we were at a safepoint allocating a new constant pool.
1467 constantPoolHandle old_cp(THREAD, the_class->constants());
1468 constantPoolHandle scratch_cp(THREAD, scratch_class->constants());
1469
1470 // If the length changed, the class was redefined out from under us. Return
1471 // an error.
1472 if (merge_cp_length != the_class->constants()->length()
1473 + scratch_class->constants()->length()) {
1474 return JVMTI_ERROR_INTERNAL;
1475 }
1476
1477 // Update the version number of the constant pools (may keep scratch_cp)
1478 merge_cp->increment_and_save_version(old_cp->version());
1479 scratch_cp->increment_and_save_version(old_cp->version());
1480
1481 ResourceMark rm(THREAD);
1482 _index_map_count = 0;
1483 _index_map_p = new intArray(scratch_cp->length(), scratch_cp->length(), -1);
1484
1485 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands());
1486 _operands_index_map_count = 0;
1487 int operands_index_map_len = ConstantPool::operand_array_length(scratch_cp->operands());
1488 _operands_index_map_p = new intArray(operands_index_map_len, operands_index_map_len, -1);
1489
1490 // reference to the cp holder is needed for copy_operands()
1491 merge_cp->set_pool_holder(scratch_class);
1492 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp,
1493 &merge_cp_length, THREAD);
1494 merge_cp->set_pool_holder(NULL);
1495
1496 if (!result) {
1497 // The merge can fail due to memory allocation failure or due
1498 // to robustness checks.
1499 return JVMTI_ERROR_INTERNAL;
1500 }
1501
1502 log_info(redefine, class, constantpool)("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count);
1503
1504 if (_index_map_count == 0) {
1505 // there is nothing to map between the new and merged constant pools
1506
1507 if (old_cp->length() == scratch_cp->length()) {
1508 // The old and new constant pools are the same length and the
1509 // index map is empty. This means that the three constant pools
1510 // are equivalent (but not the same). Unfortunately, the new
1511 // constant pool has not gone through link resolution nor have
1512 // the new class bytecodes gone through constant pool cache
1513 // rewriting so we can't use the old constant pool with the new
1514 // class.
1515
1516 // toss the merged constant pool at return
1517 } else if (old_cp->length() < scratch_cp->length()) {
1518 // The old constant pool has fewer entries than the new constant
1519 // pool and the index map is empty. This means the new constant
1520 // pool is a superset of the old constant pool. However, the old
1521 // class bytecodes have already gone through constant pool cache
1522 // rewriting so we can't use the new constant pool with the old
1523 // class.
1524
1525 // toss the merged constant pool at return
1526 } else {
1527 // The old constant pool has more entries than the new constant
1528 // pool and the index map is empty. This means that both the old
1529 // and merged constant pools are supersets of the new constant
1530 // pool.
1531
1532 // Replace the new constant pool with a shrunken copy of the
1533 // merged constant pool
1534 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1535 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1536 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1537 // It can't be cleaned up while there are handles to it.
1538 cp_cleaner.add_scratch_cp(scratch_cp());
1539 }
1540 } else {
1541 if (log_is_enabled(Trace, redefine, class, constantpool)) {
1542 // don't want to loop unless we are tracing
1543 int count = 0;
1544 for (int i = 1; i < _index_map_p->length(); i++) {
1545 int value = _index_map_p->at(i);
1546
1547 if (value != -1) {
1548 log_trace(redefine, class, constantpool)("index_map[%d]: old=%d new=%d", count, i, value);
1549 count++;
1550 }
1551 }
1552 }
1553
1554 // We have entries mapped between the new and merged constant pools
1555 // so we have to rewrite some constant pool references.
1556 if (!rewrite_cp_refs(scratch_class, THREAD)) {
1557 return JVMTI_ERROR_INTERNAL;
1558 }
1559
1560 // Replace the new constant pool with a shrunken copy of the
1561 // merged constant pool so now the rewritten bytecodes have
1562 // valid references; the previous new constant pool will get
1563 // GCed.
1564 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1565 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1566 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1567 // It can't be cleaned up while there are handles to it.
1568 cp_cleaner.add_scratch_cp(scratch_cp());
1569 }
1570
1571 return JVMTI_ERROR_NONE;
1572 } // end merge_cp_and_rewrite()
1573
1574
1575 // Rewrite constant pool references in klass scratch_class.
1576 bool VM_RedefineClasses::rewrite_cp_refs(InstanceKlass* scratch_class,
1577 TRAPS) {
1578
1579 // rewrite constant pool references in the methods:
1580 if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) {
1581 // propagate failure back to caller
1582 return false;
1583 }
1584
1585 // rewrite constant pool references in the class_annotations:
1586 if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) {
1587 // propagate failure back to caller
1588 return false;
1589 }
1590
1591 // rewrite constant pool references in the fields_annotations:
1592 if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) {
1593 // propagate failure back to caller
1594 return false;
1595 }
1596
1597 // rewrite constant pool references in the methods_annotations:
1598 if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) {
1599 // propagate failure back to caller
1600 return false;
1601 }
1602
1603 // rewrite constant pool references in the methods_parameter_annotations:
1604 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class,
1605 THREAD)) {
1606 // propagate failure back to caller
1607 return false;
1608 }
1609
1610 // rewrite constant pool references in the methods_default_annotations:
1611 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class,
1612 THREAD)) {
1613 // propagate failure back to caller
1614 return false;
1615 }
1616
1617 // rewrite constant pool references in the class_type_annotations:
1618 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class, THREAD)) {
1619 // propagate failure back to caller
1620 return false;
1621 }
1622
1623 // rewrite constant pool references in the fields_type_annotations:
1624 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class, THREAD)) {
1625 // propagate failure back to caller
1626 return false;
1627 }
1628
1629 // rewrite constant pool references in the methods_type_annotations:
1630 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class, THREAD)) {
1631 // propagate failure back to caller
1632 return false;
1633 }
1634
1635 // There can be type annotations in the Code part of a method_info attribute.
1636 // These annotations are not accessible, even by reflection.
1637 // Currently they are not even parsed by the ClassFileParser.
1638 // If runtime access is added they will also need to be rewritten.
1639
1640 // rewrite source file name index:
1641 u2 source_file_name_idx = scratch_class->source_file_name_index();
1642 if (source_file_name_idx != 0) {
1643 u2 new_source_file_name_idx = find_new_index(source_file_name_idx);
1644 if (new_source_file_name_idx != 0) {
1645 scratch_class->set_source_file_name_index(new_source_file_name_idx);
1646 }
1647 }
1648
1649 // rewrite class generic signature index:
1650 u2 generic_signature_index = scratch_class->generic_signature_index();
1651 if (generic_signature_index != 0) {
1652 u2 new_generic_signature_index = find_new_index(generic_signature_index);
1653 if (new_generic_signature_index != 0) {
1654 scratch_class->set_generic_signature_index(new_generic_signature_index);
1655 }
1656 }
1657
1658 return true;
1659 } // end rewrite_cp_refs()
1660
1661 // Rewrite constant pool references in the methods.
1662 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(
1663 InstanceKlass* scratch_class, TRAPS) {
1664
1665 Array<Method*>* methods = scratch_class->methods();
1666
1667 if (methods == NULL || methods->length() == 0) {
1668 // no methods so nothing to do
1669 return true;
1670 }
1671
1672 // rewrite constant pool references in the methods:
1673 for (int i = methods->length() - 1; i >= 0; i--) {
1674 methodHandle method(THREAD, methods->at(i));
1675 methodHandle new_method;
1676 rewrite_cp_refs_in_method(method, &new_method, THREAD);
1677 if (!new_method.is_null()) {
1678 // the method has been replaced so save the new method version
1679 // even in the case of an exception. original method is on the
1680 // deallocation list.
1681 methods->at_put(i, new_method());
1682 }
1683 if (HAS_PENDING_EXCEPTION) {
1684 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1685 log_info(redefine, class, load, exceptions)("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string());
1686 // Need to clear pending exception here as the super caller sets
1687 // the JVMTI_ERROR_INTERNAL if the returned value is false.
1688 CLEAR_PENDING_EXCEPTION;
1689 return false;
1690 }
1691 }
1692
1693 return true;
1694 }
1695
1696
1697 // Rewrite constant pool references in the specific method. This code
1698 // was adapted from Rewriter::rewrite_method().
1699 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method,
1700 methodHandle *new_method_p, TRAPS) {
1701
1702 *new_method_p = methodHandle(); // default is no new method
1703
1704 // We cache a pointer to the bytecodes here in code_base. If GC
1705 // moves the Method*, then the bytecodes will also move which
1706 // will likely cause a crash. We create a NoSafepointVerifier
1707 // object to detect whether we pass a possible safepoint in this
1708 // code block.
1709 NoSafepointVerifier nsv;
1710
1711 // Bytecodes and their length
1712 address code_base = method->code_base();
1713 int code_length = method->code_size();
1714
1715 int bc_length;
1716 for (int bci = 0; bci < code_length; bci += bc_length) {
1717 address bcp = code_base + bci;
1718 Bytecodes::Code c = (Bytecodes::Code)(*bcp);
1719
1720 bc_length = Bytecodes::length_for(c);
1721 if (bc_length == 0) {
1722 // More complicated bytecodes report a length of zero so
1723 // we have to try again a slightly different way.
1724 bc_length = Bytecodes::length_at(method(), bcp);
1725 }
1726
1727 assert(bc_length != 0, "impossible bytecode length");
1728
1729 switch (c) {
1730 case Bytecodes::_ldc:
1731 {
1732 int cp_index = *(bcp + 1);
1733 int new_index = find_new_index(cp_index);
1734
1735 if (StressLdcRewrite && new_index == 0) {
1736 // If we are stressing ldc -> ldc_w rewriting, then we
1737 // always need a new_index value.
1738 new_index = cp_index;
1739 }
1740 if (new_index != 0) {
1741 // the original index is mapped so we have more work to do
1742 if (!StressLdcRewrite && new_index <= max_jubyte) {
1743 // The new value can still use ldc instead of ldc_w
1744 // unless we are trying to stress ldc -> ldc_w rewriting
1745 log_trace(redefine, class, constantpool)
1746 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index);
1747 *(bcp + 1) = new_index;
1748 } else {
1749 log_trace(redefine, class, constantpool)
1750 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index);
1751 // the new value needs ldc_w instead of ldc
1752 u_char inst_buffer[4]; // max instruction size is 4 bytes
1753 bcp = (address)inst_buffer;
1754 // construct new instruction sequence
1755 *bcp = Bytecodes::_ldc_w;
1756 bcp++;
1757 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w.
1758 // See comment below for difference between put_Java_u2()
1759 // and put_native_u2().
1760 Bytes::put_Java_u2(bcp, new_index);
1761
1762 Relocator rc(method, NULL /* no RelocatorListener needed */);
1763 methodHandle m;
1764 {
1765 PauseNoSafepointVerifier pnsv(&nsv);
1766
1767 // ldc is 2 bytes and ldc_w is 3 bytes
1768 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK);
1769 }
1770
1771 // return the new method so that the caller can update
1772 // the containing class
1773 *new_method_p = method = m;
1774 // switch our bytecode processing loop from the old method
1775 // to the new method
1776 code_base = method->code_base();
1777 code_length = method->code_size();
1778 bcp = code_base + bci;
1779 c = (Bytecodes::Code)(*bcp);
1780 bc_length = Bytecodes::length_for(c);
1781 assert(bc_length != 0, "sanity check");
1782 } // end we need ldc_w instead of ldc
1783 } // end if there is a mapped index
1784 } break;
1785
1786 // these bytecodes have a two-byte constant pool index
1787 case Bytecodes::_anewarray : // fall through
1788 case Bytecodes::_checkcast : // fall through
1789 case Bytecodes::_getfield : // fall through
1790 case Bytecodes::_getstatic : // fall through
1791 case Bytecodes::_instanceof : // fall through
1792 case Bytecodes::_invokedynamic : // fall through
1793 case Bytecodes::_invokeinterface: // fall through
1794 case Bytecodes::_invokespecial : // fall through
1795 case Bytecodes::_invokestatic : // fall through
1796 case Bytecodes::_invokevirtual : // fall through
1797 case Bytecodes::_ldc_w : // fall through
1798 case Bytecodes::_ldc2_w : // fall through
1799 case Bytecodes::_multianewarray : // fall through
1800 case Bytecodes::_new : // fall through
1801 case Bytecodes::_putfield : // fall through
1802 case Bytecodes::_putstatic :
1803 {
1804 address p = bcp + 1;
1805 int cp_index = Bytes::get_Java_u2(p);
1806 int new_index = find_new_index(cp_index);
1807 if (new_index != 0) {
1808 // the original index is mapped so update w/ new value
1809 log_trace(redefine, class, constantpool)
1810 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),p2i(bcp), cp_index, new_index);
1811 // Rewriter::rewrite_method() uses put_native_u2() in this
1812 // situation because it is reusing the constant pool index
1813 // location for a native index into the ConstantPoolCache.
1814 // Since we are updating the constant pool index prior to
1815 // verification and ConstantPoolCache initialization, we
1816 // need to keep the new index in Java byte order.
1817 Bytes::put_Java_u2(p, new_index);
1818 }
1819 } break;
1820 }
1821 } // end for each bytecode
1822
1823 // We also need to rewrite the parameter name indexes, if there is
1824 // method parameter data present
1825 if(method->has_method_parameters()) {
1826 const int len = method->method_parameters_length();
1827 MethodParametersElement* elem = method->method_parameters_start();
1828
1829 for (int i = 0; i < len; i++) {
1830 const u2 cp_index = elem[i].name_cp_index;
1831 const u2 new_cp_index = find_new_index(cp_index);
1832 if (new_cp_index != 0) {
1833 elem[i].name_cp_index = new_cp_index;
1834 }
1835 }
1836 }
1837 } // end rewrite_cp_refs_in_method()
1838
1839
1840 // Rewrite constant pool references in the class_annotations field.
1841 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(
1842 InstanceKlass* scratch_class, TRAPS) {
1843
1844 AnnotationArray* class_annotations = scratch_class->class_annotations();
1845 if (class_annotations == NULL || class_annotations->length() == 0) {
1846 // no class_annotations so nothing to do
1847 return true;
1848 }
1849
1850 log_debug(redefine, class, annotation)("class_annotations length=%d", class_annotations->length());
1851
1852 int byte_i = 0; // byte index into class_annotations
1853 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i,
1854 THREAD);
1855 }
1856
1857
1858 // Rewrite constant pool references in an annotations typeArray. This
1859 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute
1860 // that is described in section 4.8.15 of the 2nd-edition of the VM spec:
1861 //
1862 // annotations_typeArray {
1863 // u2 num_annotations;
1864 // annotation annotations[num_annotations];
1865 // }
1866 //
1867 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray(
1868 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1869
1870 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1871 // not enough room for num_annotations field
1872 log_debug(redefine, class, annotation)("length() is too small for num_annotations field");
1873 return false;
1874 }
1875
1876 u2 num_annotations = Bytes::get_Java_u2((address)
1877 annotations_typeArray->adr_at(byte_i_ref));
1878 byte_i_ref += 2;
1879
1880 log_debug(redefine, class, annotation)("num_annotations=%d", num_annotations);
1881
1882 int calc_num_annotations = 0;
1883 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
1884 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
1885 byte_i_ref, THREAD)) {
1886 log_debug(redefine, class, annotation)("bad annotation_struct at %d", calc_num_annotations);
1887 // propagate failure back to caller
1888 return false;
1889 }
1890 }
1891 assert(num_annotations == calc_num_annotations, "sanity check");
1892
1893 return true;
1894 } // end rewrite_cp_refs_in_annotations_typeArray()
1895
1896
1897 // Rewrite constant pool references in the annotation struct portion of
1898 // an annotations_typeArray. This "structure" is from section 4.8.15 of
1899 // the 2nd-edition of the VM spec:
1900 //
1901 // struct annotation {
1902 // u2 type_index;
1903 // u2 num_element_value_pairs;
1904 // {
1905 // u2 element_name_index;
1906 // element_value value;
1907 // } element_value_pairs[num_element_value_pairs];
1908 // }
1909 //
1910 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct(
1911 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1912 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) {
1913 // not enough room for smallest annotation_struct
1914 log_debug(redefine, class, annotation)("length() is too small for annotation_struct");
1915 return false;
1916 }
1917
1918 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray,
1919 byte_i_ref, "type_index", THREAD);
1920
1921 u2 num_element_value_pairs = Bytes::get_Java_u2((address)
1922 annotations_typeArray->adr_at(byte_i_ref));
1923 byte_i_ref += 2;
1924
1925 log_debug(redefine, class, annotation)
1926 ("type_index=%d num_element_value_pairs=%d", type_index, num_element_value_pairs);
1927
1928 int calc_num_element_value_pairs = 0;
1929 for (; calc_num_element_value_pairs < num_element_value_pairs;
1930 calc_num_element_value_pairs++) {
1931 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1932 // not enough room for another element_name_index, let alone
1933 // the rest of another component
1934 log_debug(redefine, class, annotation)("length() is too small for element_name_index");
1935 return false;
1936 }
1937
1938 u2 element_name_index = rewrite_cp_ref_in_annotation_data(
1939 annotations_typeArray, byte_i_ref,
1940 "element_name_index", THREAD);
1941
1942 log_debug(redefine, class, annotation)("element_name_index=%d", element_name_index);
1943
1944 if (!rewrite_cp_refs_in_element_value(annotations_typeArray,
1945 byte_i_ref, THREAD)) {
1946 log_debug(redefine, class, annotation)("bad element_value at %d", calc_num_element_value_pairs);
1947 // propagate failure back to caller
1948 return false;
1949 }
1950 } // end for each component
1951 assert(num_element_value_pairs == calc_num_element_value_pairs,
1952 "sanity check");
1953
1954 return true;
1955 } // end rewrite_cp_refs_in_annotation_struct()
1956
1957
1958 // Rewrite a constant pool reference at the current position in
1959 // annotations_typeArray if needed. Returns the original constant
1960 // pool reference if a rewrite was not needed or the new constant
1961 // pool reference if a rewrite was needed.
1962 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data(
1963 AnnotationArray* annotations_typeArray, int &byte_i_ref,
1964 const char * trace_mesg, TRAPS) {
1965
1966 address cp_index_addr = (address)
1967 annotations_typeArray->adr_at(byte_i_ref);
1968 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr);
1969 u2 new_cp_index = find_new_index(old_cp_index);
1970 if (new_cp_index != 0) {
1971 log_debug(redefine, class, annotation)("mapped old %s=%d", trace_mesg, old_cp_index);
1972 Bytes::put_Java_u2(cp_index_addr, new_cp_index);
1973 old_cp_index = new_cp_index;
1974 }
1975 byte_i_ref += 2;
1976 return old_cp_index;
1977 }
1978
1979
1980 // Rewrite constant pool references in the element_value portion of an
1981 // annotations_typeArray. This "structure" is from section 4.8.15.1 of
1982 // the 2nd-edition of the VM spec:
1983 //
1984 // struct element_value {
1985 // u1 tag;
1986 // union {
1987 // u2 const_value_index;
1988 // {
1989 // u2 type_name_index;
1990 // u2 const_name_index;
1991 // } enum_const_value;
1992 // u2 class_info_index;
1993 // annotation annotation_value;
1994 // struct {
1995 // u2 num_values;
1996 // element_value values[num_values];
1997 // } array_value;
1998 // } value;
1999 // }
2000 //
2001 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value(
2002 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
2003
2004 if ((byte_i_ref + 1) > annotations_typeArray->length()) {
2005 // not enough room for a tag let alone the rest of an element_value
2006 log_debug(redefine, class, annotation)("length() is too small for a tag");
2007 return false;
2008 }
2009
2010 u1 tag = annotations_typeArray->at(byte_i_ref);
2011 byte_i_ref++;
2012 log_debug(redefine, class, annotation)("tag='%c'", tag);
2013
2014 switch (tag) {
2015 // These BaseType tag values are from Table 4.2 in VM spec:
2016 case 'B': // byte
2017 case 'C': // char
2018 case 'D': // double
2019 case 'F': // float
2020 case 'I': // int
2021 case 'J': // long
2022 case 'S': // short
2023 case 'Z': // boolean
2024
2025 // The remaining tag values are from Table 4.8 in the 2nd-edition of
2026 // the VM spec:
2027 case 's':
2028 {
2029 // For the above tag values (including the BaseType values),
2030 // value.const_value_index is right union field.
2031
2032 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2033 // not enough room for a const_value_index
2034 log_debug(redefine, class, annotation)("length() is too small for a const_value_index");
2035 return false;
2036 }
2037
2038 u2 const_value_index = rewrite_cp_ref_in_annotation_data(
2039 annotations_typeArray, byte_i_ref,
2040 "const_value_index", THREAD);
2041
2042 log_debug(redefine, class, annotation)("const_value_index=%d", const_value_index);
2043 } break;
2044
2045 case 'e':
2046 {
2047 // for the above tag value, value.enum_const_value is right union field
2048
2049 if ((byte_i_ref + 4) > annotations_typeArray->length()) {
2050 // not enough room for a enum_const_value
2051 log_debug(redefine, class, annotation)("length() is too small for a enum_const_value");
2052 return false;
2053 }
2054
2055 u2 type_name_index = rewrite_cp_ref_in_annotation_data(
2056 annotations_typeArray, byte_i_ref,
2057 "type_name_index", THREAD);
2058
2059 u2 const_name_index = rewrite_cp_ref_in_annotation_data(
2060 annotations_typeArray, byte_i_ref,
2061 "const_name_index", THREAD);
2062
2063 log_debug(redefine, class, annotation)
2064 ("type_name_index=%d const_name_index=%d", type_name_index, const_name_index);
2065 } break;
2066
2067 case 'c':
2068 {
2069 // for the above tag value, value.class_info_index is right union field
2070
2071 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2072 // not enough room for a class_info_index
2073 log_debug(redefine, class, annotation)("length() is too small for a class_info_index");
2074 return false;
2075 }
2076
2077 u2 class_info_index = rewrite_cp_ref_in_annotation_data(
2078 annotations_typeArray, byte_i_ref,
2079 "class_info_index", THREAD);
2080
2081 log_debug(redefine, class, annotation)("class_info_index=%d", class_info_index);
2082 } break;
2083
2084 case '@':
2085 // For the above tag value, value.attr_value is the right union
2086 // field. This is a nested annotation.
2087 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
2088 byte_i_ref, THREAD)) {
2089 // propagate failure back to caller
2090 return false;
2091 }
2092 break;
2093
2094 case '[':
2095 {
2096 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2097 // not enough room for a num_values field
2098 log_debug(redefine, class, annotation)("length() is too small for a num_values field");
2099 return false;
2100 }
2101
2102 // For the above tag value, value.array_value is the right union
2103 // field. This is an array of nested element_value.
2104 u2 num_values = Bytes::get_Java_u2((address)
2105 annotations_typeArray->adr_at(byte_i_ref));
2106 byte_i_ref += 2;
2107 log_debug(redefine, class, annotation)("num_values=%d", num_values);
2108
2109 int calc_num_values = 0;
2110 for (; calc_num_values < num_values; calc_num_values++) {
2111 if (!rewrite_cp_refs_in_element_value(
2112 annotations_typeArray, byte_i_ref, THREAD)) {
2113 log_debug(redefine, class, annotation)("bad nested element_value at %d", calc_num_values);
2114 // propagate failure back to caller
2115 return false;
2116 }
2117 }
2118 assert(num_values == calc_num_values, "sanity check");
2119 } break;
2120
2121 default:
2122 log_debug(redefine, class, annotation)("bad tag=0x%x", tag);
2123 return false;
2124 } // end decode tag field
2125
2126 return true;
2127 } // end rewrite_cp_refs_in_element_value()
2128
2129
2130 // Rewrite constant pool references in a fields_annotations field.
2131 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations(
2132 InstanceKlass* scratch_class, TRAPS) {
2133
2134 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations();
2135
2136 if (fields_annotations == NULL || fields_annotations->length() == 0) {
2137 // no fields_annotations so nothing to do
2138 return true;
2139 }
2140
2141 log_debug(redefine, class, annotation)("fields_annotations length=%d", fields_annotations->length());
2142
2143 for (int i = 0; i < fields_annotations->length(); i++) {
2144 AnnotationArray* field_annotations = fields_annotations->at(i);
2145 if (field_annotations == NULL || field_annotations->length() == 0) {
2146 // this field does not have any annotations so skip it
2147 continue;
2148 }
2149
2150 int byte_i = 0; // byte index into field_annotations
2151 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i,
2152 THREAD)) {
2153 log_debug(redefine, class, annotation)("bad field_annotations at %d", i);
2154 // propagate failure back to caller
2155 return false;
2156 }
2157 }
2158
2159 return true;
2160 } // end rewrite_cp_refs_in_fields_annotations()
2161
2162
2163 // Rewrite constant pool references in a methods_annotations field.
2164 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations(
2165 InstanceKlass* scratch_class, TRAPS) {
2166
2167 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2168 Method* m = scratch_class->methods()->at(i);
2169 AnnotationArray* method_annotations = m->constMethod()->method_annotations();
2170
2171 if (method_annotations == NULL || method_annotations->length() == 0) {
2172 // this method does not have any annotations so skip it
2173 continue;
2174 }
2175
2176 int byte_i = 0; // byte index into method_annotations
2177 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i,
2178 THREAD)) {
2179 log_debug(redefine, class, annotation)("bad method_annotations at %d", i);
2180 // propagate failure back to caller
2181 return false;
2182 }
2183 }
2184
2185 return true;
2186 } // end rewrite_cp_refs_in_methods_annotations()
2187
2188
2189 // Rewrite constant pool references in a methods_parameter_annotations
2190 // field. This "structure" is adapted from the
2191 // RuntimeVisibleParameterAnnotations_attribute described in section
2192 // 4.8.17 of the 2nd-edition of the VM spec:
2193 //
2194 // methods_parameter_annotations_typeArray {
2195 // u1 num_parameters;
2196 // {
2197 // u2 num_annotations;
2198 // annotation annotations[num_annotations];
2199 // } parameter_annotations[num_parameters];
2200 // }
2201 //
2202 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations(
2203 InstanceKlass* scratch_class, TRAPS) {
2204
2205 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2206 Method* m = scratch_class->methods()->at(i);
2207 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations();
2208 if (method_parameter_annotations == NULL
2209 || method_parameter_annotations->length() == 0) {
2210 // this method does not have any parameter annotations so skip it
2211 continue;
2212 }
2213
2214 if (method_parameter_annotations->length() < 1) {
2215 // not enough room for a num_parameters field
2216 log_debug(redefine, class, annotation)("length() is too small for a num_parameters field at %d", i);
2217 return false;
2218 }
2219
2220 int byte_i = 0; // byte index into method_parameter_annotations
2221
2222 u1 num_parameters = method_parameter_annotations->at(byte_i);
2223 byte_i++;
2224
2225 log_debug(redefine, class, annotation)("num_parameters=%d", num_parameters);
2226
2227 int calc_num_parameters = 0;
2228 for (; calc_num_parameters < num_parameters; calc_num_parameters++) {
2229 if (!rewrite_cp_refs_in_annotations_typeArray(
2230 method_parameter_annotations, byte_i, THREAD)) {
2231 log_debug(redefine, class, annotation)("bad method_parameter_annotations at %d", calc_num_parameters);
2232 // propagate failure back to caller
2233 return false;
2234 }
2235 }
2236 assert(num_parameters == calc_num_parameters, "sanity check");
2237 }
2238
2239 return true;
2240 } // end rewrite_cp_refs_in_methods_parameter_annotations()
2241
2242
2243 // Rewrite constant pool references in a methods_default_annotations
2244 // field. This "structure" is adapted from the AnnotationDefault_attribute
2245 // that is described in section 4.8.19 of the 2nd-edition of the VM spec:
2246 //
2247 // methods_default_annotations_typeArray {
2248 // element_value default_value;
2249 // }
2250 //
2251 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations(
2252 InstanceKlass* scratch_class, TRAPS) {
2253
2254 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2255 Method* m = scratch_class->methods()->at(i);
2256 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations();
2257 if (method_default_annotations == NULL
2258 || method_default_annotations->length() == 0) {
2259 // this method does not have any default annotations so skip it
2260 continue;
2261 }
2262
2263 int byte_i = 0; // byte index into method_default_annotations
2264
2265 if (!rewrite_cp_refs_in_element_value(
2266 method_default_annotations, byte_i, THREAD)) {
2267 log_debug(redefine, class, annotation)("bad default element_value at %d", i);
2268 // propagate failure back to caller
2269 return false;
2270 }
2271 }
2272
2273 return true;
2274 } // end rewrite_cp_refs_in_methods_default_annotations()
2275
2276
2277 // Rewrite constant pool references in a class_type_annotations field.
2278 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations(
2279 InstanceKlass* scratch_class, TRAPS) {
2280
2281 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations();
2282 if (class_type_annotations == NULL || class_type_annotations->length() == 0) {
2283 // no class_type_annotations so nothing to do
2284 return true;
2285 }
2286
2287 log_debug(redefine, class, annotation)("class_type_annotations length=%d", class_type_annotations->length());
2288
2289 int byte_i = 0; // byte index into class_type_annotations
2290 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations,
2291 byte_i, "ClassFile", THREAD);
2292 } // end rewrite_cp_refs_in_class_type_annotations()
2293
2294
2295 // Rewrite constant pool references in a fields_type_annotations field.
2296 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations(
2297 InstanceKlass* scratch_class, TRAPS) {
2298
2299 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations();
2300 if (fields_type_annotations == NULL || fields_type_annotations->length() == 0) {
2301 // no fields_type_annotations so nothing to do
2302 return true;
2303 }
2304
2305 log_debug(redefine, class, annotation)("fields_type_annotations length=%d", fields_type_annotations->length());
2306
2307 for (int i = 0; i < fields_type_annotations->length(); i++) {
2308 AnnotationArray* field_type_annotations = fields_type_annotations->at(i);
2309 if (field_type_annotations == NULL || field_type_annotations->length() == 0) {
2310 // this field does not have any annotations so skip it
2311 continue;
2312 }
2313
2314 int byte_i = 0; // byte index into field_type_annotations
2315 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations,
2316 byte_i, "field_info", THREAD)) {
2317 log_debug(redefine, class, annotation)("bad field_type_annotations at %d", i);
2318 // propagate failure back to caller
2319 return false;
2320 }
2321 }
2322
2323 return true;
2324 } // end rewrite_cp_refs_in_fields_type_annotations()
2325
2326
2327 // Rewrite constant pool references in a methods_type_annotations field.
2328 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations(
2329 InstanceKlass* scratch_class, TRAPS) {
2330
2331 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2332 Method* m = scratch_class->methods()->at(i);
2333 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations();
2334
2335 if (method_type_annotations == NULL || method_type_annotations->length() == 0) {
2336 // this method does not have any annotations so skip it
2337 continue;
2338 }
2339
2340 log_debug(redefine, class, annotation)("methods type_annotations length=%d", method_type_annotations->length());
2341
2342 int byte_i = 0; // byte index into method_type_annotations
2343 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations,
2344 byte_i, "method_info", THREAD)) {
2345 log_debug(redefine, class, annotation)("bad method_type_annotations at %d", i);
2346 // propagate failure back to caller
2347 return false;
2348 }
2349 }
2350
2351 return true;
2352 } // end rewrite_cp_refs_in_methods_type_annotations()
2353
2354
2355 // Rewrite constant pool references in a type_annotations
2356 // field. This "structure" is adapted from the
2357 // RuntimeVisibleTypeAnnotations_attribute described in
2358 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2359 //
2360 // type_annotations_typeArray {
2361 // u2 num_annotations;
2362 // type_annotation annotations[num_annotations];
2363 // }
2364 //
2365 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray(
2366 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2367 const char * location_mesg, TRAPS) {
2368
2369 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2370 // not enough room for num_annotations field
2371 log_debug(redefine, class, annotation)("length() is too small for num_annotations field");
2372 return false;
2373 }
2374
2375 u2 num_annotations = Bytes::get_Java_u2((address)
2376 type_annotations_typeArray->adr_at(byte_i_ref));
2377 byte_i_ref += 2;
2378
2379 log_debug(redefine, class, annotation)("num_type_annotations=%d", num_annotations);
2380
2381 int calc_num_annotations = 0;
2382 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
2383 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray,
2384 byte_i_ref, location_mesg, THREAD)) {
2385 log_debug(redefine, class, annotation)("bad type_annotation_struct at %d", calc_num_annotations);
2386 // propagate failure back to caller
2387 return false;
2388 }
2389 }
2390 assert(num_annotations == calc_num_annotations, "sanity check");
2391
2392 if (byte_i_ref != type_annotations_typeArray->length()) {
2393 log_debug(redefine, class, annotation)
2394 ("read wrong amount of bytes at end of processing type_annotations_typeArray (%d of %d bytes were read)",
2395 byte_i_ref, type_annotations_typeArray->length());
2396 return false;
2397 }
2398
2399 return true;
2400 } // end rewrite_cp_refs_in_type_annotations_typeArray()
2401
2402
2403 // Rewrite constant pool references in a type_annotation
2404 // field. This "structure" is adapted from the
2405 // RuntimeVisibleTypeAnnotations_attribute described in
2406 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2407 //
2408 // type_annotation {
2409 // u1 target_type;
2410 // union {
2411 // type_parameter_target;
2412 // supertype_target;
2413 // type_parameter_bound_target;
2414 // empty_target;
2415 // method_formal_parameter_target;
2416 // throws_target;
2417 // localvar_target;
2418 // catch_target;
2419 // offset_target;
2420 // type_argument_target;
2421 // } target_info;
2422 // type_path target_path;
2423 // annotation anno;
2424 // }
2425 //
2426 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct(
2427 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2428 const char * location_mesg, TRAPS) {
2429
2430 if (!skip_type_annotation_target(type_annotations_typeArray,
2431 byte_i_ref, location_mesg, THREAD)) {
2432 return false;
2433 }
2434
2435 if (!skip_type_annotation_type_path(type_annotations_typeArray,
2436 byte_i_ref, THREAD)) {
2437 return false;
2438 }
2439
2440 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray,
2441 byte_i_ref, THREAD)) {
2442 return false;
2443 }
2444
2445 return true;
2446 } // end rewrite_cp_refs_in_type_annotation_struct()
2447
2448
2449 // Read, verify and skip over the target_type and target_info part
2450 // so that rewriting can continue in the later parts of the struct.
2451 //
2452 // u1 target_type;
2453 // union {
2454 // type_parameter_target;
2455 // supertype_target;
2456 // type_parameter_bound_target;
2457 // empty_target;
2458 // method_formal_parameter_target;
2459 // throws_target;
2460 // localvar_target;
2461 // catch_target;
2462 // offset_target;
2463 // type_argument_target;
2464 // } target_info;
2465 //
2466 bool VM_RedefineClasses::skip_type_annotation_target(
2467 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2468 const char * location_mesg, TRAPS) {
2469
2470 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2471 // not enough room for a target_type let alone the rest of a type_annotation
2472 log_debug(redefine, class, annotation)("length() is too small for a target_type");
2473 return false;
2474 }
2475
2476 u1 target_type = type_annotations_typeArray->at(byte_i_ref);
2477 byte_i_ref += 1;
2478 log_debug(redefine, class, annotation)("target_type=0x%.2x", target_type);
2479 log_debug(redefine, class, annotation)("location=%s", location_mesg);
2480
2481 // Skip over target_info
2482 switch (target_type) {
2483 case 0x00:
2484 // kind: type parameter declaration of generic class or interface
2485 // location: ClassFile
2486 case 0x01:
2487 // kind: type parameter declaration of generic method or constructor
2488 // location: method_info
2489
2490 {
2491 // struct:
2492 // type_parameter_target {
2493 // u1 type_parameter_index;
2494 // }
2495 //
2496 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2497 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_target");
2498 return false;
2499 }
2500
2501 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2502 byte_i_ref += 1;
2503
2504 log_debug(redefine, class, annotation)("type_parameter_target: type_parameter_index=%d", type_parameter_index);
2505 } break;
2506
2507 case 0x10:
2508 // kind: type in extends clause of class or interface declaration
2509 // (including the direct superclass of an anonymous class declaration),
2510 // or in implements clause of interface declaration
2511 // location: ClassFile
2512
2513 {
2514 // struct:
2515 // supertype_target {
2516 // u2 supertype_index;
2517 // }
2518 //
2519 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2520 log_debug(redefine, class, annotation)("length() is too small for a supertype_target");
2521 return false;
2522 }
2523
2524 u2 supertype_index = Bytes::get_Java_u2((address)
2525 type_annotations_typeArray->adr_at(byte_i_ref));
2526 byte_i_ref += 2;
2527
2528 log_debug(redefine, class, annotation)("supertype_target: supertype_index=%d", supertype_index);
2529 } break;
2530
2531 case 0x11:
2532 // kind: type in bound of type parameter declaration of generic class or interface
2533 // location: ClassFile
2534 case 0x12:
2535 // kind: type in bound of type parameter declaration of generic method or constructor
2536 // location: method_info
2537
2538 {
2539 // struct:
2540 // type_parameter_bound_target {
2541 // u1 type_parameter_index;
2542 // u1 bound_index;
2543 // }
2544 //
2545 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2546 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_bound_target");
2547 return false;
2548 }
2549
2550 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2551 byte_i_ref += 1;
2552 u1 bound_index = type_annotations_typeArray->at(byte_i_ref);
2553 byte_i_ref += 1;
2554
2555 log_debug(redefine, class, annotation)
2556 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d", type_parameter_index, bound_index);
2557 } break;
2558
2559 case 0x13:
2560 // kind: type in field declaration
2561 // location: field_info
2562 case 0x14:
2563 // kind: return type of method, or type of newly constructed object
2564 // location: method_info
2565 case 0x15:
2566 // kind: receiver type of method or constructor
2567 // location: method_info
2568
2569 {
2570 // struct:
2571 // empty_target {
2572 // }
2573 //
2574 log_debug(redefine, class, annotation)("empty_target");
2575 } break;
2576
2577 case 0x16:
2578 // kind: type in formal parameter declaration of method, constructor, or lambda expression
2579 // location: method_info
2580
2581 {
2582 // struct:
2583 // formal_parameter_target {
2584 // u1 formal_parameter_index;
2585 // }
2586 //
2587 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2588 log_debug(redefine, class, annotation)("length() is too small for a formal_parameter_target");
2589 return false;
2590 }
2591
2592 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2593 byte_i_ref += 1;
2594
2595 log_debug(redefine, class, annotation)
2596 ("formal_parameter_target: formal_parameter_index=%d", formal_parameter_index);
2597 } break;
2598
2599 case 0x17:
2600 // kind: type in throws clause of method or constructor
2601 // location: method_info
2602
2603 {
2604 // struct:
2605 // throws_target {
2606 // u2 throws_type_index
2607 // }
2608 //
2609 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2610 log_debug(redefine, class, annotation)("length() is too small for a throws_target");
2611 return false;
2612 }
2613
2614 u2 throws_type_index = Bytes::get_Java_u2((address)
2615 type_annotations_typeArray->adr_at(byte_i_ref));
2616 byte_i_ref += 2;
2617
2618 log_debug(redefine, class, annotation)("throws_target: throws_type_index=%d", throws_type_index);
2619 } break;
2620
2621 case 0x40:
2622 // kind: type in local variable declaration
2623 // location: Code
2624 case 0x41:
2625 // kind: type in resource variable declaration
2626 // location: Code
2627
2628 {
2629 // struct:
2630 // localvar_target {
2631 // u2 table_length;
2632 // struct {
2633 // u2 start_pc;
2634 // u2 length;
2635 // u2 index;
2636 // } table[table_length];
2637 // }
2638 //
2639 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2640 // not enough room for a table_length let alone the rest of a localvar_target
2641 log_debug(redefine, class, annotation)("length() is too small for a localvar_target table_length");
2642 return false;
2643 }
2644
2645 u2 table_length = Bytes::get_Java_u2((address)
2646 type_annotations_typeArray->adr_at(byte_i_ref));
2647 byte_i_ref += 2;
2648
2649 log_debug(redefine, class, annotation)("localvar_target: table_length=%d", table_length);
2650
2651 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry
2652 int table_size = table_length * table_struct_size;
2653
2654 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) {
2655 // not enough room for a table
2656 log_debug(redefine, class, annotation)("length() is too small for a table array of length %d", table_length);
2657 return false;
2658 }
2659
2660 // Skip over table
2661 byte_i_ref += table_size;
2662 } break;
2663
2664 case 0x42:
2665 // kind: type in exception parameter declaration
2666 // location: Code
2667
2668 {
2669 // struct:
2670 // catch_target {
2671 // u2 exception_table_index;
2672 // }
2673 //
2674 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2675 log_debug(redefine, class, annotation)("length() is too small for a catch_target");
2676 return false;
2677 }
2678
2679 u2 exception_table_index = Bytes::get_Java_u2((address)
2680 type_annotations_typeArray->adr_at(byte_i_ref));
2681 byte_i_ref += 2;
2682
2683 log_debug(redefine, class, annotation)("catch_target: exception_table_index=%d", exception_table_index);
2684 } break;
2685
2686 case 0x43:
2687 // kind: type in instanceof expression
2688 // location: Code
2689 case 0x44:
2690 // kind: type in new expression
2691 // location: Code
2692 case 0x45:
2693 // kind: type in method reference expression using ::new
2694 // location: Code
2695 case 0x46:
2696 // kind: type in method reference expression using ::Identifier
2697 // location: Code
2698
2699 {
2700 // struct:
2701 // offset_target {
2702 // u2 offset;
2703 // }
2704 //
2705 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2706 log_debug(redefine, class, annotation)("length() is too small for a offset_target");
2707 return false;
2708 }
2709
2710 u2 offset = Bytes::get_Java_u2((address)
2711 type_annotations_typeArray->adr_at(byte_i_ref));
2712 byte_i_ref += 2;
2713
2714 log_debug(redefine, class, annotation)("offset_target: offset=%d", offset);
2715 } break;
2716
2717 case 0x47:
2718 // kind: type in cast expression
2719 // location: Code
2720 case 0x48:
2721 // kind: type argument for generic constructor in new expression or
2722 // explicit constructor invocation statement
2723 // location: Code
2724 case 0x49:
2725 // kind: type argument for generic method in method invocation expression
2726 // location: Code
2727 case 0x4A:
2728 // kind: type argument for generic constructor in method reference expression using ::new
2729 // location: Code
2730 case 0x4B:
2731 // kind: type argument for generic method in method reference expression using ::Identifier
2732 // location: Code
2733
2734 {
2735 // struct:
2736 // type_argument_target {
2737 // u2 offset;
2738 // u1 type_argument_index;
2739 // }
2740 //
2741 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) {
2742 log_debug(redefine, class, annotation)("length() is too small for a type_argument_target");
2743 return false;
2744 }
2745
2746 u2 offset = Bytes::get_Java_u2((address)
2747 type_annotations_typeArray->adr_at(byte_i_ref));
2748 byte_i_ref += 2;
2749 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
2750 byte_i_ref += 1;
2751
2752 log_debug(redefine, class, annotation)
2753 ("type_argument_target: offset=%d, type_argument_index=%d", offset, type_argument_index);
2754 } break;
2755
2756 default:
2757 log_debug(redefine, class, annotation)("unknown target_type");
2758 #ifdef ASSERT
2759 ShouldNotReachHere();
2760 #endif
2761 return false;
2762 }
2763
2764 return true;
2765 } // end skip_type_annotation_target()
2766
2767
2768 // Read, verify and skip over the type_path part so that rewriting
2769 // can continue in the later parts of the struct.
2770 //
2771 // type_path {
2772 // u1 path_length;
2773 // {
2774 // u1 type_path_kind;
2775 // u1 type_argument_index;
2776 // } path[path_length];
2777 // }
2778 //
2779 bool VM_RedefineClasses::skip_type_annotation_type_path(
2780 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, TRAPS) {
2781
2782 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2783 // not enough room for a path_length let alone the rest of the type_path
2784 log_debug(redefine, class, annotation)("length() is too small for a type_path");
2785 return false;
2786 }
2787
2788 u1 path_length = type_annotations_typeArray->at(byte_i_ref);
2789 byte_i_ref += 1;
2790
2791 log_debug(redefine, class, annotation)("type_path: path_length=%d", path_length);
2792
2793 int calc_path_length = 0;
2794 for (; calc_path_length < path_length; calc_path_length++) {
2795 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) {
2796 // not enough room for a path
2797 log_debug(redefine, class, annotation)
2798 ("length() is too small for path entry %d of %d", calc_path_length, path_length);
2799 return false;
2800 }
2801
2802 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref);
2803 byte_i_ref += 1;
2804 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
2805 byte_i_ref += 1;
2806
2807 log_debug(redefine, class, annotation)
2808 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d",
2809 calc_path_length, type_path_kind, type_argument_index);
2810
2811 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) {
2812 // not enough room for a path
2813 log_debug(redefine, class, annotation)("inconsistent type_path values");
2814 return false;
2815 }
2816 }
2817 assert(path_length == calc_path_length, "sanity check");
2818
2819 return true;
2820 } // end skip_type_annotation_type_path()
2821
2822
2823 // Rewrite constant pool references in the method's stackmap table.
2824 // These "structures" are adapted from the StackMapTable_attribute that
2825 // is described in section 4.8.4 of the 6.0 version of the VM spec
2826 // (dated 2005.10.26):
2827 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2828 //
2829 // stack_map {
2830 // u2 number_of_entries;
2831 // stack_map_frame entries[number_of_entries];
2832 // }
2833 //
2834 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table(
2835 const methodHandle& method, TRAPS) {
2836
2837 if (!method->has_stackmap_table()) {
2838 return;
2839 }
2840
2841 AnnotationArray* stackmap_data = method->stackmap_data();
2842 address stackmap_p = (address)stackmap_data->adr_at(0);
2843 address stackmap_end = stackmap_p + stackmap_data->length();
2844
2845 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries");
2846 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p);
2847 stackmap_p += 2;
2848
2849 log_debug(redefine, class, stackmap)("number_of_entries=%u", number_of_entries);
2850
2851 // walk through each stack_map_frame
2852 u2 calc_number_of_entries = 0;
2853 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) {
2854 // The stack_map_frame structure is a u1 frame_type followed by
2855 // 0 or more bytes of data:
2856 //
2857 // union stack_map_frame {
2858 // same_frame;
2859 // same_locals_1_stack_item_frame;
2860 // same_locals_1_stack_item_frame_extended;
2861 // chop_frame;
2862 // same_frame_extended;
2863 // append_frame;
2864 // full_frame;
2865 // }
2866
2867 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type");
2868 u1 frame_type = *stackmap_p;
2869 stackmap_p++;
2870
2871 // same_frame {
2872 // u1 frame_type = SAME; /* 0-63 */
2873 // }
2874 if (frame_type <= 63) {
2875 // nothing more to do for same_frame
2876 }
2877
2878 // same_locals_1_stack_item_frame {
2879 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */
2880 // verification_type_info stack[1];
2881 // }
2882 else if (frame_type >= 64 && frame_type <= 127) {
2883 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2884 calc_number_of_entries, frame_type, THREAD);
2885 }
2886
2887 // reserved for future use
2888 else if (frame_type >= 128 && frame_type <= 246) {
2889 // nothing more to do for reserved frame_types
2890 }
2891
2892 // same_locals_1_stack_item_frame_extended {
2893 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */
2894 // u2 offset_delta;
2895 // verification_type_info stack[1];
2896 // }
2897 else if (frame_type == 247) {
2898 stackmap_p += 2;
2899 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2900 calc_number_of_entries, frame_type, THREAD);
2901 }
2902
2903 // chop_frame {
2904 // u1 frame_type = CHOP; /* 248-250 */
2905 // u2 offset_delta;
2906 // }
2907 else if (frame_type >= 248 && frame_type <= 250) {
2908 stackmap_p += 2;
2909 }
2910
2911 // same_frame_extended {
2912 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/
2913 // u2 offset_delta;
2914 // }
2915 else if (frame_type == 251) {
2916 stackmap_p += 2;
2917 }
2918
2919 // append_frame {
2920 // u1 frame_type = APPEND; /* 252-254 */
2921 // u2 offset_delta;
2922 // verification_type_info locals[frame_type - 251];
2923 // }
2924 else if (frame_type >= 252 && frame_type <= 254) {
2925 assert(stackmap_p + 2 <= stackmap_end,
2926 "no room for offset_delta");
2927 stackmap_p += 2;
2928 u1 len = frame_type - 251;
2929 for (u1 i = 0; i < len; i++) {
2930 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2931 calc_number_of_entries, frame_type, THREAD);
2932 }
2933 }
2934
2935 // full_frame {
2936 // u1 frame_type = FULL_FRAME; /* 255 */
2937 // u2 offset_delta;
2938 // u2 number_of_locals;
2939 // verification_type_info locals[number_of_locals];
2940 // u2 number_of_stack_items;
2941 // verification_type_info stack[number_of_stack_items];
2942 // }
2943 else if (frame_type == 255) {
2944 assert(stackmap_p + 2 + 2 <= stackmap_end,
2945 "no room for smallest full_frame");
2946 stackmap_p += 2;
2947
2948 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p);
2949 stackmap_p += 2;
2950
2951 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) {
2952 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2953 calc_number_of_entries, frame_type, THREAD);
2954 }
2955
2956 // Use the largest size for the number_of_stack_items, but only get
2957 // the right number of bytes.
2958 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p);
2959 stackmap_p += 2;
2960
2961 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) {
2962 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2963 calc_number_of_entries, frame_type, THREAD);
2964 }
2965 }
2966 } // end while there is a stack_map_frame
2967 assert(number_of_entries == calc_number_of_entries, "sanity check");
2968 } // end rewrite_cp_refs_in_stack_map_table()
2969
2970
2971 // Rewrite constant pool references in the verification type info
2972 // portion of the method's stackmap table. These "structures" are
2973 // adapted from the StackMapTable_attribute that is described in
2974 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26):
2975 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2976 //
2977 // The verification_type_info structure is a u1 tag followed by 0 or
2978 // more bytes of data:
2979 //
2980 // union verification_type_info {
2981 // Top_variable_info;
2982 // Integer_variable_info;
2983 // Float_variable_info;
2984 // Long_variable_info;
2985 // Double_variable_info;
2986 // Null_variable_info;
2987 // UninitializedThis_variable_info;
2988 // Object_variable_info;
2989 // Uninitialized_variable_info;
2990 // }
2991 //
2992 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info(
2993 address& stackmap_p_ref, address stackmap_end, u2 frame_i,
2994 u1 frame_type, TRAPS) {
2995
2996 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag");
2997 u1 tag = *stackmap_p_ref;
2998 stackmap_p_ref++;
2999
3000 switch (tag) {
3001 // Top_variable_info {
3002 // u1 tag = ITEM_Top; /* 0 */
3003 // }
3004 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top
3005 case 0: // fall through
3006
3007 // Integer_variable_info {
3008 // u1 tag = ITEM_Integer; /* 1 */
3009 // }
3010 case ITEM_Integer: // fall through
3011
3012 // Float_variable_info {
3013 // u1 tag = ITEM_Float; /* 2 */
3014 // }
3015 case ITEM_Float: // fall through
3016
3017 // Double_variable_info {
3018 // u1 tag = ITEM_Double; /* 3 */
3019 // }
3020 case ITEM_Double: // fall through
3021
3022 // Long_variable_info {
3023 // u1 tag = ITEM_Long; /* 4 */
3024 // }
3025 case ITEM_Long: // fall through
3026
3027 // Null_variable_info {
3028 // u1 tag = ITEM_Null; /* 5 */
3029 // }
3030 case ITEM_Null: // fall through
3031
3032 // UninitializedThis_variable_info {
3033 // u1 tag = ITEM_UninitializedThis; /* 6 */
3034 // }
3035 case ITEM_UninitializedThis:
3036 // nothing more to do for the above tag types
3037 break;
3038
3039 // Object_variable_info {
3040 // u1 tag = ITEM_Object; /* 7 */
3041 // u2 cpool_index;
3042 // }
3043 case ITEM_Object:
3044 {
3045 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index");
3046 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref);
3047 u2 new_cp_index = find_new_index(cpool_index);
3048 if (new_cp_index != 0) {
3049 log_debug(redefine, class, stackmap)("mapped old cpool_index=%d", cpool_index);
3050 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
3051 cpool_index = new_cp_index;
3052 }
3053 stackmap_p_ref += 2;
3054
3055 log_debug(redefine, class, stackmap)
3056 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i, frame_type, cpool_index);
3057 } break;
3058
3059 // Uninitialized_variable_info {
3060 // u1 tag = ITEM_Uninitialized; /* 8 */
3061 // u2 offset;
3062 // }
3063 case ITEM_Uninitialized:
3064 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset");
3065 stackmap_p_ref += 2;
3066 break;
3067
3068 default:
3069 log_debug(redefine, class, stackmap)("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag);
3070 ShouldNotReachHere();
3071 break;
3072 } // end switch (tag)
3073 } // end rewrite_cp_refs_in_verification_type_info()
3074
3075
3076 // Change the constant pool associated with klass scratch_class to
3077 // scratch_cp. If shrink is true, then scratch_cp_length elements
3078 // are copied from scratch_cp to a smaller constant pool and the
3079 // smaller constant pool is associated with scratch_class.
3080 void VM_RedefineClasses::set_new_constant_pool(
3081 ClassLoaderData* loader_data,
3082 InstanceKlass* scratch_class, constantPoolHandle scratch_cp,
3083 int scratch_cp_length, TRAPS) {
3084 assert(scratch_cp->length() >= scratch_cp_length, "sanity check");
3085
3086 // scratch_cp is a merged constant pool and has enough space for a
3087 // worst case merge situation. We want to associate the minimum
3088 // sized constant pool with the klass to save space.
3089 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK);
3090 constantPoolHandle smaller_cp(THREAD, cp);
3091
3092 // preserve version() value in the smaller copy
3093 int version = scratch_cp->version();
3094 assert(version != 0, "sanity check");
3095 smaller_cp->set_version(version);
3096
3097 // attach klass to new constant pool
3098 // reference to the cp holder is needed for copy_operands()
3099 smaller_cp->set_pool_holder(scratch_class);
3100
3101 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
3102 if (HAS_PENDING_EXCEPTION) {
3103 // Exception is handled in the caller
3104 loader_data->add_to_deallocate_list(smaller_cp());
3105 return;
3106 }
3107 scratch_cp = smaller_cp;
3108
3109 // attach new constant pool to klass
3110 scratch_class->set_constants(scratch_cp());
3111 scratch_cp->initialize_unresolved_klasses(loader_data, CHECK);
3112
3113 int i; // for portability
3114
3115 // update each field in klass to use new constant pool indices as needed
3116 for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) {
3117 jshort cur_index = fs.name_index();
3118 jshort new_index = find_new_index(cur_index);
3119 if (new_index != 0) {
3120 log_trace(redefine, class, constantpool)("field-name_index change: %d to %d", cur_index, new_index);
3121 fs.set_name_index(new_index);
3122 }
3123 cur_index = fs.signature_index();
3124 new_index = find_new_index(cur_index);
3125 if (new_index != 0) {
3126 log_trace(redefine, class, constantpool)("field-signature_index change: %d to %d", cur_index, new_index);
3127 fs.set_signature_index(new_index);
3128 }
3129 cur_index = fs.initval_index();
3130 new_index = find_new_index(cur_index);
3131 if (new_index != 0) {
3132 log_trace(redefine, class, constantpool)("field-initval_index change: %d to %d", cur_index, new_index);
3133 fs.set_initval_index(new_index);
3134 }
3135 cur_index = fs.generic_signature_index();
3136 new_index = find_new_index(cur_index);
3137 if (new_index != 0) {
3138 log_trace(redefine, class, constantpool)("field-generic_signature change: %d to %d", cur_index, new_index);
3139 fs.set_generic_signature_index(new_index);
3140 }
3141 } // end for each field
3142
3143 // Update constant pool indices in the inner classes info to use
3144 // new constant indices as needed. The inner classes info is a
3145 // quadruple:
3146 // (inner_class_info, outer_class_info, inner_name, inner_access_flags)
3147 InnerClassesIterator iter(scratch_class);
3148 for (; !iter.done(); iter.next()) {
3149 int cur_index = iter.inner_class_info_index();
3150 if (cur_index == 0) {
3151 continue; // JVM spec. allows null inner class refs so skip it
3152 }
3153 int new_index = find_new_index(cur_index);
3154 if (new_index != 0) {
3155 log_trace(redefine, class, constantpool)("inner_class_info change: %d to %d", cur_index, new_index);
3156 iter.set_inner_class_info_index(new_index);
3157 }
3158 cur_index = iter.outer_class_info_index();
3159 new_index = find_new_index(cur_index);
3160 if (new_index != 0) {
3161 log_trace(redefine, class, constantpool)("outer_class_info change: %d to %d", cur_index, new_index);
3162 iter.set_outer_class_info_index(new_index);
3163 }
3164 cur_index = iter.inner_name_index();
3165 new_index = find_new_index(cur_index);
3166 if (new_index != 0) {
3167 log_trace(redefine, class, constantpool)("inner_name change: %d to %d", cur_index, new_index);
3168 iter.set_inner_name_index(new_index);
3169 }
3170 } // end for each inner class
3171
3172 // Attach each method in klass to the new constant pool and update
3173 // to use new constant pool indices as needed:
3174 Array<Method*>* methods = scratch_class->methods();
3175 for (i = methods->length() - 1; i >= 0; i--) {
3176 methodHandle method(THREAD, methods->at(i));
3177 method->set_constants(scratch_cp());
3178
3179 int new_index = find_new_index(method->name_index());
3180 if (new_index != 0) {
3181 log_trace(redefine, class, constantpool)
3182 ("method-name_index change: %d to %d", method->name_index(), new_index);
3183 method->set_name_index(new_index);
3184 }
3185 new_index = find_new_index(method->signature_index());
3186 if (new_index != 0) {
3187 log_trace(redefine, class, constantpool)
3188 ("method-signature_index change: %d to %d", method->signature_index(), new_index);
3189 method->set_signature_index(new_index);
3190 }
3191 new_index = find_new_index(method->generic_signature_index());
3192 if (new_index != 0) {
3193 log_trace(redefine, class, constantpool)
3194 ("method-generic_signature_index change: %d to %d", method->generic_signature_index(), new_index);
3195 method->set_generic_signature_index(new_index);
3196 }
3197
3198 // Update constant pool indices in the method's checked exception
3199 // table to use new constant indices as needed.
3200 int cext_length = method->checked_exceptions_length();
3201 if (cext_length > 0) {
3202 CheckedExceptionElement * cext_table =
3203 method->checked_exceptions_start();
3204 for (int j = 0; j < cext_length; j++) {
3205 int cur_index = cext_table[j].class_cp_index;
3206 int new_index = find_new_index(cur_index);
3207 if (new_index != 0) {
3208 log_trace(redefine, class, constantpool)("cext-class_cp_index change: %d to %d", cur_index, new_index);
3209 cext_table[j].class_cp_index = (u2)new_index;
3210 }
3211 } // end for each checked exception table entry
3212 } // end if there are checked exception table entries
3213
3214 // Update each catch type index in the method's exception table
3215 // to use new constant pool indices as needed. The exception table
3216 // holds quadruple entries of the form:
3217 // (beg_bci, end_bci, handler_bci, klass_index)
3218
3219 ExceptionTable ex_table(method());
3220 int ext_length = ex_table.length();
3221
3222 for (int j = 0; j < ext_length; j ++) {
3223 int cur_index = ex_table.catch_type_index(j);
3224 int new_index = find_new_index(cur_index);
3225 if (new_index != 0) {
3226 log_trace(redefine, class, constantpool)("ext-klass_index change: %d to %d", cur_index, new_index);
3227 ex_table.set_catch_type_index(j, new_index);
3228 }
3229 } // end for each exception table entry
3230
3231 // Update constant pool indices in the method's local variable
3232 // table to use new constant indices as needed. The local variable
3233 // table hold sextuple entries of the form:
3234 // (start_pc, length, name_index, descriptor_index, signature_index, slot)
3235 int lvt_length = method->localvariable_table_length();
3236 if (lvt_length > 0) {
3237 LocalVariableTableElement * lv_table =
3238 method->localvariable_table_start();
3239 for (int j = 0; j < lvt_length; j++) {
3240 int cur_index = lv_table[j].name_cp_index;
3241 int new_index = find_new_index(cur_index);
3242 if (new_index != 0) {
3243 log_trace(redefine, class, constantpool)("lvt-name_cp_index change: %d to %d", cur_index, new_index);
3244 lv_table[j].name_cp_index = (u2)new_index;
3245 }
3246 cur_index = lv_table[j].descriptor_cp_index;
3247 new_index = find_new_index(cur_index);
3248 if (new_index != 0) {
3249 log_trace(redefine, class, constantpool)("lvt-descriptor_cp_index change: %d to %d", cur_index, new_index);
3250 lv_table[j].descriptor_cp_index = (u2)new_index;
3251 }
3252 cur_index = lv_table[j].signature_cp_index;
3253 new_index = find_new_index(cur_index);
3254 if (new_index != 0) {
3255 log_trace(redefine, class, constantpool)("lvt-signature_cp_index change: %d to %d", cur_index, new_index);
3256 lv_table[j].signature_cp_index = (u2)new_index;
3257 }
3258 } // end for each local variable table entry
3259 } // end if there are local variable table entries
3260
3261 rewrite_cp_refs_in_stack_map_table(method, THREAD);
3262 } // end for each method
3263 } // end set_new_constant_pool()
3264
3265
3266 // Unevolving classes may point to methods of the_class directly
3267 // from their constant pool caches, itables, and/or vtables. We
3268 // use the ClassLoaderDataGraph::classes_do() facility and this helper
3269 // to fix up these pointers.
3270
3271 // Adjust cpools and vtables closure
3272 void VM_RedefineClasses::AdjustCpoolCacheAndVtable::do_klass(Klass* k) {
3273
3274 // This is a very busy routine. We don't want too much tracing
3275 // printed out.
3276 bool trace_name_printed = false;
3277 InstanceKlass *the_class = InstanceKlass::cast(_the_class);
3278
3279 // If the class being redefined is java.lang.Object, we need to fix all
3280 // array class vtables also
3281 if (k->is_array_klass() && _the_class == SystemDictionary::Object_klass()) {
3282 k->vtable()->adjust_method_entries(the_class, &trace_name_printed);
3283
3284 } else if (k->is_instance_klass()) {
3285 HandleMark hm(_thread);
3286 InstanceKlass *ik = InstanceKlass::cast(k);
3287
3288 // HotSpot specific optimization! HotSpot does not currently
3289 // support delegation from the bootstrap class loader to a
3290 // user-defined class loader. This means that if the bootstrap
3291 // class loader is the initiating class loader, then it will also
3292 // be the defining class loader. This also means that classes
3293 // loaded by the bootstrap class loader cannot refer to classes
3294 // loaded by a user-defined class loader. Note: a user-defined
3295 // class loader can delegate to the bootstrap class loader.
3296 //
3297 // If the current class being redefined has a user-defined class
3298 // loader as its defining class loader, then we can skip all
3299 // classes loaded by the bootstrap class loader.
3300 bool is_user_defined = (_the_class->class_loader() != NULL);
3301 if (is_user_defined && ik->class_loader() == NULL) {
3302 return;
3303 }
3304
3305 // Fix the vtable embedded in the_class and subclasses of the_class,
3306 // if one exists. We discard scratch_class and we don't keep an
3307 // InstanceKlass around to hold obsolete methods so we don't have
3308 // any other InstanceKlass embedded vtables to update. The vtable
3309 // holds the Method*s for virtual (but not final) methods.
3310 // Default methods, or concrete methods in interfaces are stored
3311 // in the vtable, so if an interface changes we need to check
3312 // adjust_method_entries() for every InstanceKlass, which will also
3313 // adjust the default method vtable indices.
3314 // We also need to adjust any default method entries that are
3315 // not yet in the vtable, because the vtable setup is in progress.
3316 // This must be done after we adjust the default_methods and
3317 // default_vtable_indices for methods already in the vtable.
3318 // If redefining Unsafe, walk all the vtables looking for entries.
3319 if (ik->vtable_length() > 0 && (_the_class->is_interface()
3320 || _the_class == SystemDictionary::internal_Unsafe_klass()
3321 || ik->is_subtype_of(_the_class))) {
3322 // ik->vtable() creates a wrapper object; rm cleans it up
3323 ResourceMark rm(_thread);
3324
3325 ik->vtable()->adjust_method_entries(the_class, &trace_name_printed);
3326 ik->adjust_default_methods(the_class, &trace_name_printed);
3327 }
3328
3329 // If the current class has an itable and we are either redefining an
3330 // interface or if the current class is a subclass of the_class, then
3331 // we potentially have to fix the itable. If we are redefining an
3332 // interface, then we have to call adjust_method_entries() for
3333 // every InstanceKlass that has an itable since there isn't a
3334 // subclass relationship between an interface and an InstanceKlass.
3335 // If redefining Unsafe, walk all the itables looking for entries.
3336 if (ik->itable_length() > 0 && (_the_class->is_interface()
3337 || _the_class == SystemDictionary::internal_Unsafe_klass()
3338 || ik->is_subclass_of(_the_class))) {
3339 // ik->itable() creates a wrapper object; rm cleans it up
3340 ResourceMark rm(_thread);
3341
3342 ik->itable()->adjust_method_entries(the_class, &trace_name_printed);
3343 }
3344
3345 // The constant pools in other classes (other_cp) can refer to
3346 // methods in the_class. We have to update method information in
3347 // other_cp's cache. If other_cp has a previous version, then we
3348 // have to repeat the process for each previous version. The
3349 // constant pool cache holds the Method*s for non-virtual
3350 // methods and for virtual, final methods.
3351 //
3352 // Special case: if the current class is the_class, then new_cp
3353 // has already been attached to the_class and old_cp has already
3354 // been added as a previous version. The new_cp doesn't have any
3355 // cached references to old methods so it doesn't need to be
3356 // updated. We can simply start with the previous version(s) in
3357 // that case.
3358 constantPoolHandle other_cp;
3359 ConstantPoolCache* cp_cache;
3360
3361 if (ik != _the_class) {
3362 // this klass' constant pool cache may need adjustment
3363 other_cp = constantPoolHandle(ik->constants());
3364 cp_cache = other_cp->cache();
3365 if (cp_cache != NULL) {
3366 cp_cache->adjust_method_entries(the_class, &trace_name_printed);
3367 }
3368 }
3369
3370 // the previous versions' constant pool caches may need adjustment
3371 for (InstanceKlass* pv_node = ik->previous_versions();
3372 pv_node != NULL;
3373 pv_node = pv_node->previous_versions()) {
3374 cp_cache = pv_node->constants()->cache();
3375 if (cp_cache != NULL) {
3376 cp_cache->adjust_method_entries(pv_node, &trace_name_printed);
3377 }
3378 }
3379 }
3380 }
3381
3382 // Clean method data for this class
3383 void VM_RedefineClasses::MethodDataCleaner::do_klass(Klass* k) {
3384 if (k->is_instance_klass()) {
3385 InstanceKlass *ik = InstanceKlass::cast(k);
3386 // Clean MethodData of this class's methods so they don't refer to
3387 // old methods that are no longer running.
3388 Array<Method*>* methods = ik->methods();
3389 int num_methods = methods->length();
3390 for (int index = 0; index < num_methods; ++index) {
3391 if (methods->at(index)->method_data() != NULL) {
3392 methods->at(index)->method_data()->clean_weak_method_links();
3393 }
3394 }
3395 }
3396 }
3397
3398 void VM_RedefineClasses::update_jmethod_ids() {
3399 for (int j = 0; j < _matching_methods_length; ++j) {
3400 Method* old_method = _matching_old_methods[j];
3401 jmethodID jmid = old_method->find_jmethod_id_or_null();
3402 if (jmid != NULL) {
3403 // There is a jmethodID, change it to point to the new method
3404 methodHandle new_method_h(_matching_new_methods[j]);
3405 Method::change_method_associated_with_jmethod_id(jmid, new_method_h());
3406 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j],
3407 "should be replaced");
3408 }
3409 }
3410 }
3411
3412 int VM_RedefineClasses::check_methods_and_mark_as_obsolete() {
3413 int emcp_method_count = 0;
3414 int obsolete_count = 0;
3415 int old_index = 0;
3416 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
3417 Method* old_method = _matching_old_methods[j];
3418 Method* new_method = _matching_new_methods[j];
3419 Method* old_array_method;
3420
3421 // Maintain an old_index into the _old_methods array by skipping
3422 // deleted methods
3423 while ((old_array_method = _old_methods->at(old_index)) != old_method) {
3424 ++old_index;
3425 }
3426
3427 if (MethodComparator::methods_EMCP(old_method, new_method)) {
3428 // The EMCP definition from JSR-163 requires the bytecodes to be
3429 // the same with the exception of constant pool indices which may
3430 // differ. However, the constants referred to by those indices
3431 // must be the same.
3432 //
3433 // We use methods_EMCP() for comparison since constant pool
3434 // merging can remove duplicate constant pool entries that were
3435 // present in the old method and removed from the rewritten new
3436 // method. A faster binary comparison function would consider the
3437 // old and new methods to be different when they are actually
3438 // EMCP.
3439 //
3440 // The old and new methods are EMCP and you would think that we
3441 // could get rid of one of them here and now and save some space.
3442 // However, the concept of EMCP only considers the bytecodes and
3443 // the constant pool entries in the comparison. Other things,
3444 // e.g., the line number table (LNT) or the local variable table
3445 // (LVT) don't count in the comparison. So the new (and EMCP)
3446 // method can have a new LNT that we need so we can't just
3447 // overwrite the new method with the old method.
3448 //
3449 // When this routine is called, we have already attached the new
3450 // methods to the_class so the old methods are effectively
3451 // overwritten. However, if an old method is still executing,
3452 // then the old method cannot be collected until sometime after
3453 // the old method call has returned. So the overwriting of old
3454 // methods by new methods will save us space except for those
3455 // (hopefully few) old methods that are still executing.
3456 //
3457 // A method refers to a ConstMethod* and this presents another
3458 // possible avenue to space savings. The ConstMethod* in the
3459 // new method contains possibly new attributes (LNT, LVT, etc).
3460 // At first glance, it seems possible to save space by replacing
3461 // the ConstMethod* in the old method with the ConstMethod*
3462 // from the new method. The old and new methods would share the
3463 // same ConstMethod* and we would save the space occupied by
3464 // the old ConstMethod*. However, the ConstMethod* contains
3465 // a back reference to the containing method. Sharing the
3466 // ConstMethod* between two methods could lead to confusion in
3467 // the code that uses the back reference. This would lead to
3468 // brittle code that could be broken in non-obvious ways now or
3469 // in the future.
3470 //
3471 // Another possibility is to copy the ConstMethod* from the new
3472 // method to the old method and then overwrite the new method with
3473 // the old method. Since the ConstMethod* contains the bytecodes
3474 // for the method embedded in the oop, this option would change
3475 // the bytecodes out from under any threads executing the old
3476 // method and make the thread's bcp invalid. Since EMCP requires
3477 // that the bytecodes be the same modulo constant pool indices, it
3478 // is straight forward to compute the correct new bcp in the new
3479 // ConstMethod* from the old bcp in the old ConstMethod*. The
3480 // time consuming part would be searching all the frames in all
3481 // of the threads to find all of the calls to the old method.
3482 //
3483 // It looks like we will have to live with the limited savings
3484 // that we get from effectively overwriting the old methods
3485 // when the new methods are attached to the_class.
3486
3487 // Count number of methods that are EMCP. The method will be marked
3488 // old but not obsolete if it is EMCP.
3489 emcp_method_count++;
3490
3491 // An EMCP method is _not_ obsolete. An obsolete method has a
3492 // different jmethodID than the current method. An EMCP method
3493 // has the same jmethodID as the current method. Having the
3494 // same jmethodID for all EMCP versions of a method allows for
3495 // a consistent view of the EMCP methods regardless of which
3496 // EMCP method you happen to have in hand. For example, a
3497 // breakpoint set in one EMCP method will work for all EMCP
3498 // versions of the method including the current one.
3499 } else {
3500 // mark obsolete methods as such
3501 old_method->set_is_obsolete();
3502 obsolete_count++;
3503
3504 // obsolete methods need a unique idnum so they become new entries in
3505 // the jmethodID cache in InstanceKlass
3506 assert(old_method->method_idnum() == new_method->method_idnum(), "must match");
3507 u2 num = InstanceKlass::cast(_the_class)->next_method_idnum();
3508 if (num != ConstMethod::UNSET_IDNUM) {
3509 old_method->set_method_idnum(num);
3510 }
3511
3512 // With tracing we try not to "yack" too much. The position of
3513 // this trace assumes there are fewer obsolete methods than
3514 // EMCP methods.
3515 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) {
3516 ResourceMark rm;
3517 log_trace(redefine, class, obsolete, mark)
3518 ("mark %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string());
3519 }
3520 }
3521 old_method->set_is_old();
3522 }
3523 for (int i = 0; i < _deleted_methods_length; ++i) {
3524 Method* old_method = _deleted_methods[i];
3525
3526 assert(!old_method->has_vtable_index(),
3527 "cannot delete methods with vtable entries");;
3528
3529 // Mark all deleted methods as old, obsolete and deleted
3530 old_method->set_is_deleted();
3531 old_method->set_is_old();
3532 old_method->set_is_obsolete();
3533 ++obsolete_count;
3534 // With tracing we try not to "yack" too much. The position of
3535 // this trace assumes there are fewer obsolete methods than
3536 // EMCP methods.
3537 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) {
3538 ResourceMark rm;
3539 log_trace(redefine, class, obsolete, mark)
3540 ("mark deleted %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string());
3541 }
3542 }
3543 assert((emcp_method_count + obsolete_count) == _old_methods->length(),
3544 "sanity check");
3545 log_trace(redefine, class, obsolete, mark)("EMCP_cnt=%d, obsolete_cnt=%d", emcp_method_count, obsolete_count);
3546 return emcp_method_count;
3547 }
3548
3549 // This internal class transfers the native function registration from old methods
3550 // to new methods. It is designed to handle both the simple case of unchanged
3551 // native methods and the complex cases of native method prefixes being added and/or
3552 // removed.
3553 // It expects only to be used during the VM_RedefineClasses op (a safepoint).
3554 //
3555 // This class is used after the new methods have been installed in "the_class".
3556 //
3557 // So, for example, the following must be handled. Where 'm' is a method and
3558 // a number followed by an underscore is a prefix.
3559 //
3560 // Old Name New Name
3561 // Simple transfer to new method m -> m
3562 // Add prefix m -> 1_m
3563 // Remove prefix 1_m -> m
3564 // Simultaneous add of prefixes m -> 3_2_1_m
3565 // Simultaneous removal of prefixes 3_2_1_m -> m
3566 // Simultaneous add and remove 1_m -> 2_m
3567 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m
3568 //
3569 class TransferNativeFunctionRegistration {
3570 private:
3571 InstanceKlass* the_class;
3572 int prefix_count;
3573 char** prefixes;
3574
3575 // Recursively search the binary tree of possibly prefixed method names.
3576 // Iteration could be used if all agents were well behaved. Full tree walk is
3577 // more resilent to agents not cleaning up intermediate methods.
3578 // Branch at each depth in the binary tree is:
3579 // (1) without the prefix.
3580 // (2) with the prefix.
3581 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
3582 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len,
3583 Symbol* signature) {
3584 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len);
3585 if (name_symbol != NULL) {
3586 Method* method = the_class->lookup_method(name_symbol, signature);
3587 if (method != NULL) {
3588 // Even if prefixed, intermediate methods must exist.
3589 if (method->is_native()) {
3590 // Wahoo, we found a (possibly prefixed) version of the method, return it.
3591 return method;
3592 }
3593 if (depth < prefix_count) {
3594 // Try applying further prefixes (other than this one).
3595 method = search_prefix_name_space(depth+1, name_str, name_len, signature);
3596 if (method != NULL) {
3597 return method; // found
3598 }
3599
3600 // Try adding this prefix to the method name and see if it matches
3601 // another method name.
3602 char* prefix = prefixes[depth];
3603 size_t prefix_len = strlen(prefix);
3604 size_t trial_len = name_len + prefix_len;
3605 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
3606 strcpy(trial_name_str, prefix);
3607 strcat(trial_name_str, name_str);
3608 method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
3609 signature);
3610 if (method != NULL) {
3611 // If found along this branch, it was prefixed, mark as such
3612 method->set_is_prefixed_native();
3613 return method; // found
3614 }
3615 }
3616 }
3617 }
3618 return NULL; // This whole branch bore nothing
3619 }
3620
3621 // Return the method name with old prefixes stripped away.
3622 char* method_name_without_prefixes(Method* method) {
3623 Symbol* name = method->name();
3624 char* name_str = name->as_utf8();
3625
3626 // Old prefixing may be defunct, strip prefixes, if any.
3627 for (int i = prefix_count-1; i >= 0; i--) {
3628 char* prefix = prefixes[i];
3629 size_t prefix_len = strlen(prefix);
3630 if (strncmp(prefix, name_str, prefix_len) == 0) {
3631 name_str += prefix_len;
3632 }
3633 }
3634 return name_str;
3635 }
3636
3637 // Strip any prefixes off the old native method, then try to find a
3638 // (possibly prefixed) new native that matches it.
3639 Method* strip_and_search_for_new_native(Method* method) {
3640 ResourceMark rm;
3641 char* name_str = method_name_without_prefixes(method);
3642 return search_prefix_name_space(0, name_str, strlen(name_str),
3643 method->signature());
3644 }
3645
3646 public:
3647
3648 // Construct a native method transfer processor for this class.
3649 TransferNativeFunctionRegistration(InstanceKlass* _the_class) {
3650 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
3651
3652 the_class = _the_class;
3653 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
3654 }
3655
3656 // Attempt to transfer any of the old or deleted methods that are native
3657 void transfer_registrations(Method** old_methods, int methods_length) {
3658 for (int j = 0; j < methods_length; j++) {
3659 Method* old_method = old_methods[j];
3660
3661 if (old_method->is_native() && old_method->has_native_function()) {
3662 Method* new_method = strip_and_search_for_new_native(old_method);
3663 if (new_method != NULL) {
3664 // Actually set the native function in the new method.
3665 // Redefine does not send events (except CFLH), certainly not this
3666 // behind the scenes re-registration.
3667 new_method->set_native_function(old_method->native_function(),
3668 !Method::native_bind_event_is_interesting);
3669 }
3670 }
3671 }
3672 }
3673 };
3674
3675 // Don't lose the association between a native method and its JNI function.
3676 void VM_RedefineClasses::transfer_old_native_function_registrations(InstanceKlass* the_class) {
3677 TransferNativeFunctionRegistration transfer(the_class);
3678 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length);
3679 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length);
3680 }
3681
3682 // Deoptimize all compiled code that depends on this class.
3683 //
3684 // If the can_redefine_classes capability is obtained in the onload
3685 // phase then the compiler has recorded all dependencies from startup.
3686 // In that case we need only deoptimize and throw away all compiled code
3687 // that depends on the class.
3688 //
3689 // If can_redefine_classes is obtained sometime after the onload
3690 // phase then the dependency information may be incomplete. In that case
3691 // the first call to RedefineClasses causes all compiled code to be
3692 // thrown away. As can_redefine_classes has been obtained then
3693 // all future compilations will record dependencies so second and
3694 // subsequent calls to RedefineClasses need only throw away code
3695 // that depends on the class.
3696 //
3697 void VM_RedefineClasses::flush_dependent_code(InstanceKlass* ik, TRAPS) {
3698 assert_locked_or_safepoint(Compile_lock);
3699
3700 // All dependencies have been recorded from startup or this is a second or
3701 // subsequent use of RedefineClasses
3702 if (JvmtiExport::all_dependencies_are_recorded()) {
3703 CodeCache::flush_evol_dependents_on(ik);
3704 } else {
3705 CodeCache::mark_all_nmethods_for_deoptimization();
3706
3707 ResourceMark rm(THREAD);
3708 DeoptimizationMarker dm;
3709
3710 // Deoptimize all activations depending on marked nmethods
3711 Deoptimization::deoptimize_dependents();
3712
3713 // Make the dependent methods not entrant
3714 CodeCache::make_marked_nmethods_not_entrant();
3715
3716 // From now on we know that the dependency information is complete
3717 JvmtiExport::set_all_dependencies_are_recorded(true);
3718 }
3719 }
3720
3721 void VM_RedefineClasses::compute_added_deleted_matching_methods() {
3722 Method* old_method;
3723 Method* new_method;
3724
3725 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3726 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3727 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length());
3728 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3729
3730 _matching_methods_length = 0;
3731 _deleted_methods_length = 0;
3732 _added_methods_length = 0;
3733
3734 int nj = 0;
3735 int oj = 0;
3736 while (true) {
3737 if (oj >= _old_methods->length()) {
3738 if (nj >= _new_methods->length()) {
3739 break; // we've looked at everything, done
3740 }
3741 // New method at the end
3742 new_method = _new_methods->at(nj);
3743 _added_methods[_added_methods_length++] = new_method;
3744 ++nj;
3745 } else if (nj >= _new_methods->length()) {
3746 // Old method, at the end, is deleted
3747 old_method = _old_methods->at(oj);
3748 _deleted_methods[_deleted_methods_length++] = old_method;
3749 ++oj;
3750 } else {
3751 old_method = _old_methods->at(oj);
3752 new_method = _new_methods->at(nj);
3753 if (old_method->name() == new_method->name()) {
3754 if (old_method->signature() == new_method->signature()) {
3755 _matching_old_methods[_matching_methods_length ] = old_method;
3756 _matching_new_methods[_matching_methods_length++] = new_method;
3757 ++nj;
3758 ++oj;
3759 } else {
3760 // added overloaded have already been moved to the end,
3761 // so this is a deleted overloaded method
3762 _deleted_methods[_deleted_methods_length++] = old_method;
3763 ++oj;
3764 }
3765 } else { // names don't match
3766 if (old_method->name()->fast_compare(new_method->name()) > 0) {
3767 // new method
3768 _added_methods[_added_methods_length++] = new_method;
3769 ++nj;
3770 } else {
3771 // deleted method
3772 _deleted_methods[_deleted_methods_length++] = old_method;
3773 ++oj;
3774 }
3775 }
3776 }
3777 }
3778 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
3779 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
3780 }
3781
3782
3783 void VM_RedefineClasses::swap_annotations(InstanceKlass* the_class,
3784 InstanceKlass* scratch_class) {
3785 // Swap annotation fields values
3786 Annotations* old_annotations = the_class->annotations();
3787 the_class->set_annotations(scratch_class->annotations());
3788 scratch_class->set_annotations(old_annotations);
3789 }
3790
3791
3792 // Install the redefinition of a class:
3793 // - house keeping (flushing breakpoints and caches, deoptimizing
3794 // dependent compiled code)
3795 // - replacing parts in the_class with parts from scratch_class
3796 // - adding a weak reference to track the obsolete but interesting
3797 // parts of the_class
3798 // - adjusting constant pool caches and vtables in other classes
3799 // that refer to methods in the_class. These adjustments use the
3800 // ClassLoaderDataGraph::classes_do() facility which only allows
3801 // a helper method to be specified. The interesting parameters
3802 // that we would like to pass to the helper method are saved in
3803 // static global fields in the VM operation.
3804 void VM_RedefineClasses::redefine_single_class(jclass the_jclass,
3805 InstanceKlass* scratch_class, TRAPS) {
3806
3807 HandleMark hm(THREAD); // make sure handles from this call are freed
3808
3809 if (log_is_enabled(Info, redefine, class, timer)) {
3810 _timer_rsc_phase1.start();
3811 }
3812
3813 InstanceKlass* the_class = get_ik(the_jclass);
3814
3815 // Remove all breakpoints in methods of this class
3816 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
3817 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class);
3818
3819 // Deoptimize all compiled code that depends on this class
3820 flush_dependent_code(the_class, THREAD);
3821
3822 _old_methods = the_class->methods();
3823 _new_methods = scratch_class->methods();
3824 _the_class = the_class;
3825 compute_added_deleted_matching_methods();
3826 update_jmethod_ids();
3827
3828 // Attach new constant pool to the original klass. The original
3829 // klass still refers to the old constant pool (for now).
3830 scratch_class->constants()->set_pool_holder(the_class);
3831
3832 #if 0
3833 // In theory, with constant pool merging in place we should be able
3834 // to save space by using the new, merged constant pool in place of
3835 // the old constant pool(s). By "pool(s)" I mean the constant pool in
3836 // the klass version we are replacing now and any constant pool(s) in
3837 // previous versions of klass. Nice theory, doesn't work in practice.
3838 // When this code is enabled, even simple programs throw NullPointer
3839 // exceptions. I'm guessing that this is caused by some constant pool
3840 // cache difference between the new, merged constant pool and the
3841 // constant pool that was just being used by the klass. I'm keeping
3842 // this code around to archive the idea, but the code has to remain
3843 // disabled for now.
3844
3845 // Attach each old method to the new constant pool. This can be
3846 // done here since we are past the bytecode verification and
3847 // constant pool optimization phases.
3848 for (int i = _old_methods->length() - 1; i >= 0; i--) {
3849 Method* method = _old_methods->at(i);
3850 method->set_constants(scratch_class->constants());
3851 }
3852
3853 // NOTE: this doesn't work because you can redefine the same class in two
3854 // threads, each getting their own constant pool data appended to the
3855 // original constant pool. In order for the new methods to work when they
3856 // become old methods, they need to keep their updated copy of the constant pool.
3857
3858 {
3859 // walk all previous versions of the klass
3860 InstanceKlass *ik = the_class;
3861 PreviousVersionWalker pvw(ik);
3862 do {
3863 ik = pvw.next_previous_version();
3864 if (ik != NULL) {
3865
3866 // attach previous version of klass to the new constant pool
3867 ik->set_constants(scratch_class->constants());
3868
3869 // Attach each method in the previous version of klass to the
3870 // new constant pool
3871 Array<Method*>* prev_methods = ik->methods();
3872 for (int i = prev_methods->length() - 1; i >= 0; i--) {
3873 Method* method = prev_methods->at(i);
3874 method->set_constants(scratch_class->constants());
3875 }
3876 }
3877 } while (ik != NULL);
3878 }
3879 #endif
3880
3881 // Replace methods and constantpool
3882 the_class->set_methods(_new_methods);
3883 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods,
3884 // and to be able to undo operation easily.
3885
3886 Array<int>* old_ordering = the_class->method_ordering();
3887 the_class->set_method_ordering(scratch_class->method_ordering());
3888 scratch_class->set_method_ordering(old_ordering);
3889
3890 ConstantPool* old_constants = the_class->constants();
3891 the_class->set_constants(scratch_class->constants());
3892 scratch_class->set_constants(old_constants); // See the previous comment.
3893 #if 0
3894 // We are swapping the guts of "the new class" with the guts of "the
3895 // class". Since the old constant pool has just been attached to "the
3896 // new class", it seems logical to set the pool holder in the old
3897 // constant pool also. However, doing this will change the observable
3898 // class hierarchy for any old methods that are still executing. A
3899 // method can query the identity of its "holder" and this query uses
3900 // the method's constant pool link to find the holder. The change in
3901 // holding class from "the class" to "the new class" can confuse
3902 // things.
3903 //
3904 // Setting the old constant pool's holder will also cause
3905 // verification done during vtable initialization below to fail.
3906 // During vtable initialization, the vtable's class is verified to be
3907 // a subtype of the method's holder. The vtable's class is "the
3908 // class" and the method's holder is gotten from the constant pool
3909 // link in the method itself. For "the class"'s directly implemented
3910 // methods, the method holder is "the class" itself (as gotten from
3911 // the new constant pool). The check works fine in this case. The
3912 // check also works fine for methods inherited from super classes.
3913 //
3914 // Miranda methods are a little more complicated. A miranda method is
3915 // provided by an interface when the class implementing the interface
3916 // does not provide its own method. These interfaces are implemented
3917 // internally as an InstanceKlass. These special instanceKlasses
3918 // share the constant pool of the class that "implements" the
3919 // interface. By sharing the constant pool, the method holder of a
3920 // miranda method is the class that "implements" the interface. In a
3921 // non-redefine situation, the subtype check works fine. However, if
3922 // the old constant pool's pool holder is modified, then the check
3923 // fails because there is no class hierarchy relationship between the
3924 // vtable's class and "the new class".
3925
3926 old_constants->set_pool_holder(scratch_class());
3927 #endif
3928
3929 // track number of methods that are EMCP for add_previous_version() call below
3930 int emcp_method_count = check_methods_and_mark_as_obsolete();
3931 transfer_old_native_function_registrations(the_class);
3932
3933 // The class file bytes from before any retransformable agents mucked
3934 // with them was cached on the scratch class, move to the_class.
3935 // Note: we still want to do this if nothing needed caching since it
3936 // should get cleared in the_class too.
3937 if (the_class->get_cached_class_file_bytes() == 0) {
3938 // the_class doesn't have a cache yet so copy it
3939 the_class->set_cached_class_file(scratch_class->get_cached_class_file());
3940 }
3941 else if (scratch_class->get_cached_class_file_bytes() !=
3942 the_class->get_cached_class_file_bytes()) {
3943 // The same class can be present twice in the scratch classes list or there
3944 // are multiple concurrent RetransformClasses calls on different threads.
3945 // In such cases we have to deallocate scratch_class cached_class_file.
3946 os::free(scratch_class->get_cached_class_file());
3947 }
3948
3949 // NULL out in scratch class to not delete twice. The class to be redefined
3950 // always owns these bytes.
3951 scratch_class->set_cached_class_file(NULL);
3952
3953 // Replace inner_classes
3954 Array<u2>* old_inner_classes = the_class->inner_classes();
3955 the_class->set_inner_classes(scratch_class->inner_classes());
3956 scratch_class->set_inner_classes(old_inner_classes);
3957
3958 // Initialize the vtable and interface table after
3959 // methods have been rewritten
3960 {
3961 ResourceMark rm(THREAD);
3962 // no exception should happen here since we explicitly
3963 // do not check loader constraints.
3964 // compare_and_normalize_class_versions has already checked:
3965 // - classloaders unchanged, signatures unchanged
3966 // - all instanceKlasses for redefined classes reused & contents updated
3967 the_class->vtable()->initialize_vtable(false, THREAD);
3968 the_class->itable()->initialize_itable(false, THREAD);
3969 assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())), "redefine exception");
3970 }
3971
3972 // Leave arrays of jmethodIDs and itable index cache unchanged
3973
3974 // Copy the "source file name" attribute from new class version
3975 the_class->set_source_file_name_index(
3976 scratch_class->source_file_name_index());
3977
3978 // Copy the "source debug extension" attribute from new class version
3979 the_class->set_source_debug_extension(
3980 scratch_class->source_debug_extension(),
3981 scratch_class->source_debug_extension() == NULL ? 0 :
3982 (int)strlen(scratch_class->source_debug_extension()));
3983
3984 // Use of javac -g could be different in the old and the new
3985 if (scratch_class->access_flags().has_localvariable_table() !=
3986 the_class->access_flags().has_localvariable_table()) {
3987
3988 AccessFlags flags = the_class->access_flags();
3989 if (scratch_class->access_flags().has_localvariable_table()) {
3990 flags.set_has_localvariable_table();
3991 } else {
3992 flags.clear_has_localvariable_table();
3993 }
3994 the_class->set_access_flags(flags);
3995 }
3996
3997 swap_annotations(the_class, scratch_class);
3998
3999 // Replace minor version number of class file
4000 u2 old_minor_version = the_class->minor_version();
4001 the_class->set_minor_version(scratch_class->minor_version());
4002 scratch_class->set_minor_version(old_minor_version);
4003
4004 // Replace major version number of class file
4005 u2 old_major_version = the_class->major_version();
4006 the_class->set_major_version(scratch_class->major_version());
4007 scratch_class->set_major_version(old_major_version);
4008
4009 // Replace CP indexes for class and name+type of enclosing method
4010 u2 old_class_idx = the_class->enclosing_method_class_index();
4011 u2 old_method_idx = the_class->enclosing_method_method_index();
4012 the_class->set_enclosing_method_indices(
4013 scratch_class->enclosing_method_class_index(),
4014 scratch_class->enclosing_method_method_index());
4015 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx);
4016
4017 // Replace fingerprint data
4018 the_class->set_has_passed_fingerprint_check(scratch_class->has_passed_fingerprint_check());
4019 the_class->store_fingerprint(scratch_class->get_stored_fingerprint());
4020
4021 the_class->set_has_been_redefined();
4022
4023 if (!the_class->should_be_initialized()) {
4024 // Class was already initialized, so AOT has only seen the original version.
4025 // We need to let AOT look at it again.
4026 AOTLoader::load_for_klass(the_class, THREAD);
4027 }
4028
4029 // keep track of previous versions of this class
4030 the_class->add_previous_version(scratch_class, emcp_method_count);
4031
4032 _timer_rsc_phase1.stop();
4033 if (log_is_enabled(Info, redefine, class, timer)) {
4034 _timer_rsc_phase2.start();
4035 }
4036
4037 // Adjust constantpool caches and vtables for all classes
4038 // that reference methods of the evolved class.
4039 AdjustCpoolCacheAndVtable adjust_cpool_cache_and_vtable(THREAD);
4040 ClassLoaderDataGraph::classes_do(&adjust_cpool_cache_and_vtable);
4041
4042 // JSR-292 support
4043 MemberNameTable* mnt = the_class->member_names();
4044 if (mnt != NULL) {
4045 bool trace_name_printed = false;
4046 mnt->adjust_method_entries(the_class, &trace_name_printed);
4047 }
4048
4049 if (the_class->oop_map_cache() != NULL) {
4050 // Flush references to any obsolete methods from the oop map cache
4051 // so that obsolete methods are not pinned.
4052 the_class->oop_map_cache()->flush_obsolete_entries();
4053 }
4054
4055 increment_class_counter((InstanceKlass *)the_class, THREAD);
4056 {
4057 ResourceMark rm(THREAD);
4058 // increment the classRedefinedCount field in the_class and in any
4059 // direct and indirect subclasses of the_class
4060 log_info(redefine, class, load)
4061 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)",
4062 the_class->external_name(), java_lang_Class::classRedefinedCount(the_class->java_mirror()), os::available_memory() >> 10);
4063 Events::log_redefinition(THREAD, "redefined class name=%s, count=%d",
4064 the_class->external_name(),
4065 java_lang_Class::classRedefinedCount(the_class->java_mirror()));
4066
4067 }
4068 _timer_rsc_phase2.stop();
4069 } // end redefine_single_class()
4070
4071
4072 // Increment the classRedefinedCount field in the specific InstanceKlass
4073 // and in all direct and indirect subclasses.
4074 void VM_RedefineClasses::increment_class_counter(InstanceKlass *ik, TRAPS) {
4075 oop class_mirror = ik->java_mirror();
4076 Klass* class_oop = java_lang_Class::as_Klass(class_mirror);
4077 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
4078 java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
4079
4080 if (class_oop != _the_class) {
4081 // _the_class count is printed at end of redefine_single_class()
4082 log_debug(redefine, class, subclass)("updated count in subclass=%s to %d", ik->external_name(), new_count);
4083 }
4084
4085 for (Klass *subk = ik->subklass(); subk != NULL;
4086 subk = subk->next_sibling()) {
4087 if (subk->is_instance_klass()) {
4088 // Only update instanceKlasses
4089 InstanceKlass *subik = InstanceKlass::cast(subk);
4090 // recursively do subclasses of the current subclass
4091 increment_class_counter(subik, THREAD);
4092 }
4093 }
4094 }
4095
4096 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) {
4097 bool no_old_methods = true; // be optimistic
4098
4099 // Both array and instance classes have vtables.
4100 // a vtable should never contain old or obsolete methods
4101 ResourceMark rm(_thread);
4102 if (k->vtable_length() > 0 &&
4103 !k->vtable()->check_no_old_or_obsolete_entries()) {
4104 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4105 log_trace(redefine, class, obsolete, metadata)
4106 ("klassVtable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4107 k->signature_name());
4108 k->vtable()->dump_vtable();
4109 }
4110 no_old_methods = false;
4111 }
4112
4113 if (k->is_instance_klass()) {
4114 HandleMark hm(_thread);
4115 InstanceKlass *ik = InstanceKlass::cast(k);
4116
4117 // an itable should never contain old or obsolete methods
4118 if (ik->itable_length() > 0 &&
4119 !ik->itable()->check_no_old_or_obsolete_entries()) {
4120 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4121 log_trace(redefine, class, obsolete, metadata)
4122 ("klassItable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4123 ik->signature_name());
4124 ik->itable()->dump_itable();
4125 }
4126 no_old_methods = false;
4127 }
4128
4129 // the constant pool cache should never contain non-deleted old or obsolete methods
4130 if (ik->constants() != NULL &&
4131 ik->constants()->cache() != NULL &&
4132 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) {
4133 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4134 log_trace(redefine, class, obsolete, metadata)
4135 ("cp-cache::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4136 ik->signature_name());
4137 ik->constants()->cache()->dump_cache();
4138 }
4139 no_old_methods = false;
4140 }
4141 }
4142
4143 // print and fail guarantee if old methods are found.
4144 if (!no_old_methods) {
4145 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4146 dump_methods();
4147 } else {
4148 log_trace(redefine, class)("Use the '-Xlog:redefine+class*:' option "
4149 "to see more info about the following guarantee() failure.");
4150 }
4151 guarantee(false, "OLD and/or OBSOLETE method(s) found");
4152 }
4153 }
4154
4155
4156 void VM_RedefineClasses::dump_methods() {
4157 int j;
4158 log_trace(redefine, class, dump)("_old_methods --");
4159 for (j = 0; j < _old_methods->length(); ++j) {
4160 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4161 Method* m = _old_methods->at(j);
4162 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4163 m->access_flags().print_on(&log_stream);
4164 log_stream.print(" -- ");
4165 m->print_name(&log_stream);
4166 log_stream.cr();
4167 }
4168 log_trace(redefine, class, dump)("_new_methods --");
4169 for (j = 0; j < _new_methods->length(); ++j) {
4170 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4171 Method* m = _new_methods->at(j);
4172 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4173 m->access_flags().print_on(&log_stream);
4174 log_stream.print(" -- ");
4175 m->print_name(&log_stream);
4176 log_stream.cr();
4177 }
4178 log_trace(redefine, class, dump)("_matching_methods --");
4179 for (j = 0; j < _matching_methods_length; ++j) {
4180 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4181 Method* m = _matching_old_methods[j];
4182 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4183 m->access_flags().print_on(&log_stream);
4184 log_stream.print(" -- ");
4185 m->print_name();
4186 log_stream.cr();
4187
4188 m = _matching_new_methods[j];
4189 log_stream.print(" (%5d) ", m->vtable_index());
4190 m->access_flags().print_on(&log_stream);
4191 log_stream.cr();
4192 }
4193 log_trace(redefine, class, dump)("_deleted_methods --");
4194 for (j = 0; j < _deleted_methods_length; ++j) {
4195 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4196 Method* m = _deleted_methods[j];
4197 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4198 m->access_flags().print_on(&log_stream);
4199 log_stream.print(" -- ");
4200 m->print_name(&log_stream);
4201 log_stream.cr();
4202 }
4203 log_trace(redefine, class, dump)("_added_methods --");
4204 for (j = 0; j < _added_methods_length; ++j) {
4205 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4206 Method* m = _added_methods[j];
4207 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4208 m->access_flags().print_on(&log_stream);
4209 log_stream.print(" -- ");
4210 m->print_name(&log_stream);
4211 log_stream.cr();
4212 }
4213 }
4214
4215 void VM_RedefineClasses::print_on_error(outputStream* st) const {
4216 VM_Operation::print_on_error(st);
4217 if (_the_class != NULL) {
4218 ResourceMark rm;
4219 st->print_cr(", redefining class %s", _the_class->external_name());
4220 }
4221 }